Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/07/12
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
849 PM MST THU DEC 6 2012
.UPDATE...FORECAST ON TRACK. CURRENT SATELLITE SHOWS WAVE CLOUDS
BEGINNING TO SPREAD DOWN THE FRONT RANGE AS UPPER LEVEL MOISTURE
INCREASES. WE SHOULD SEE A DECENT MOUNTAIN WAVE DEVELOP LATER
TONIGHT WITH INCREASING PRESSURE GRADIENT AND 30-40 KT CROSS
MOUNTAIN FLOW...BUT STABLE LAYER IS A LITTLE TOO HIGH FOR
SIGNIFICANT ENHANCEMENT. IN ANY CASE...ENOUGH CROSS MOUNTAIN
FLOW TO BOOST WIND FORECAST ABOUT 5-10 MPH FOR THE MOUNTAINS AND
FOOTHILLS TONIGHT INTO FRIDAY.
&&
.AVIATION...CURRENT TAFS AND PREVIOUS AVIATION DISCUSSION LOOK
GOOD. NO CHANGES.
&&
.PREV DISCUSSION... /ISSUED 303 PM MST THU DEC 6 2012/
SHORT TERM...MID LEVEL SHORT WAVE MOVING INTO CENTRAL PLAINS WITH
DRYING AND SUBSIDENCE OVERTAKING CFWA. SNOW SHOWERS ACROSS
MOUNTAINS HAVE BEEN ON THE DECREASE BUT STILL DECENT OROGRAPHICS
FOR SOME LIGHT SNOW HUGGING CONTINENTAL DIVIDE AS SHOWN BE WEB
CAMS. ALSO SOME SHOWERS ACROSS PARK COUNTY. MODEL CROSS SECTIONS
SHOW A DECREASE IN MOISTURE THROUGH THE EVENING...SO TREND OF
DECREASING SNOW STILL LOOKING REASONABLE. FLOW ALOFT INCREASES
AFTER MIDNIGHT WITH RUC CROSS SECTIONS SHOWING CROSS MOUNTAIN FLOW
INCREASING TO 40 KTS AT MOUNTAIN TOP BY 08Z. FORECAST SOUNDINGS
SHOWING MOUNTAIN TOP INVERSION DEVELOPING AFTER 06Z WITH POTENTIAL
FOR A MOUNTAIN WAVE. WITH INCREASING MID LEVEL SUBSIDENCE
EXPECTED...SHOULD SEE WINDS INCREASE AFTER MIDNIGHT...ESPECIALLY
ACROSS MOUNTAINS AND NORTHERN FOOTHILLS BUT SHOULD STAY BELOW HIGH
WIND CRITERIA. ON FRIDAY... MODERATE WESTERLY FLOW ALOFT TO
CONTINUE. WINDS TO REMAIN GUSTY ACROSS THE MOUNTAINS AND ALONG
FOOTHILLS...WITH A SLIGHT DECREASE BY THE AFTERNOON. MODEL CROSS
SECTIONS SHOW MOISTURE INCREASING DURING THE MORNING ALONG WITH
SOME INCREASE IN MID LEVEL QG ASCENT. WITH FAVORABLE OROGRAPHICS
EXPECTED ACROSS MOUNTAINS...SHOULD SEE SNOW CHANCES INCREASE BY
THE AFTERNOON. ANY ACCUMULATIONS EXPECTED TO BE LIGHT AND
CONFINED THE THE WEST FACING SLOPES. ACROSS PLAINS...DRY
CONDITIONS TO PREVAIL WITH A GRADUAL INCREASE IN CLOUD COVER.
TEMPERATURE AND THICKNESS GUIDANCE SHOWING LITTLE CHANGE FROM
TODAY`S READINGS...PERHAPS A FEW DEGREES WARMER ACROSS PLAINS.
LONG TERM...TO START OFF...THERE`S A POSSIBILITY OF STRONG IF NOT
HIGH WINDS IN THE MTNS AND FRONT RANGE FOOTHILLS FRIDAY NIGHT AND
SATURDAY MORNING. MODELS SHOW A +120KT POLAR JET ROUNDING THE
SOUTH SIDE OF POTENT UPPER LEVEL TROUGH TRANSLATES SOUTHWARD OVER
THE FORECAST AREA LATE ON FRIDAY. THE CORE OF THIS JET IS PROGGED
TO PASS OVER THE FRONT RANGE BETWEEN 06Z-12Z/SATURDAY. AT THE
SAME TIME...AS THE MTN LAYER GROWS INCREASINGLY STABLE AND CROSS
SECTIONS SHOW A HIGH AMPLITUDE MTN WAVE FORMING OVER THE FRONT
RANGE WITH A CROSS BARRIER WIND COMPONENT OF 60-75 KTS WITHIN THE
700-550 MB LAYER. MAY BE NECESSARY TO ISSUE A HIGH WIND WATCH FOR
THE RIDGES AND EAST SLOPES OF MTN ZONES 33..34 AND FOOTHILL ZONES
35 AND 36 SHOULD THE NEXT MODEL RUN CONTINUE TO INDICATE WINDS OF
THIS MAGNITUDE. ATTENTION NEXT TURNS TO THE APPROACHING TROUGH/S
IMPACT ON THE FORECAST AREA THIS WEEKEND. STARTING WITH SATURDAY...
STG AND GUSTY WEST-NORTHWEST WINDS IN THE MTNS AND FTHLS SHOULD
EASE WITH THE JET CONTINUING TO MIGRATE SOUTH. AN POCKET OF
MODERATE QG ASCENT COUPLED WITH UPSLOPE FORCING SHOULD BEGIN TO
CRANK OUT SNOW IN THE NRN MTN RANGES BY EARLY AFTERNOON ON
SATURDAY...IF NOT SOONER. THROUGH THE DAY SHOW SEE THIS SNOW FIELD
SPREADING SOUTHWARD AS COLD AIR SPILLS IN FROM WYOMING. ON THE
PLAINS...CONDITIONS LOOK DRY IN THE MORNING WITH LIGHT DOWNSLOPE
FLOW. HOWEVER BY LATE IN THE DAY COULD SEE A FEW SHOWERS DRIFTING
OFF THE NRN FRONT RANGE AND OVER PORTIONS OF THE I-25 URBAN
CORRIDOR. TEMPERATURES STILL LOOK TOO WARM FOR ANYTHING BUT
RAIN...ALTHOUGH RIDGE UP AGAINST THE FOOTHILLS AND NEAR THE WY
BORDER...COULD SEE A RAIN/SNOW MIX BEFORE SUNSET. THEN
OVERNIGHT...FORCING FOR ASCENT INCREASES AS THE CORE OF THE UPPER
TROUGH MAKES ITS WAY OVER SRN WY/NRN COLORADO. A MAJORITY OF THE
MODELS ALSO SHOW A STRONG COLD FRONT DROP SOUTH ACROSS THE PLAINS
DURING THE ERLY EVENING HOURS. THIS SETS IN PLAY AT LEAST 9 HRS OF
ANTICYCLONIC UPSLOPE FLOW FOR AREAS ROUGHLY EAST OF THE
CONTINENTAL DIVIDE. BEST OROGRAPHIC LIFT OCCURS FM 06Z TO
15Z/SUNDAY. THIS IS THE PERIOD WHEN MODELS GENERATE THE BULK OF
PCPN/SNOWFALL FOR THE FORECAST AREA. SNOW TOTALS...STILL
TENTATIVE...VARY FROM 3-9 INCHES IN THE HIGH COUNTRY...TO A TRACE
UP TO 5 INCHES ON THE PLAINS. MAY SEE A BIT MORE FOR THE PALMER
DIVIDE WHERE N-NELY BNDRY FLOW WOULD FAVOR MORE SNOW FORMATION.
ON SUNDAY...MODELS SHOW THE TROUGH DROPPING SOUTH-SOUTHEAST WHICH
PULLS INCREASINGLY COLDER AIR DOWN FOR WYOMING THROUGH THE DAY.
SUNDAY APPEARS TO BE THE COLDEST DAY FOR THE NEXT SEVERAL DAYS
WITH HIGHS ON SUNDAY AS MUCH AS 15-25F BELOW AVERAGE...WITH
COLDEST DAYTIME TEMPERATURES EAST OF THE MTNS. BY SUNDAY NIGHT
UNDER CLEARING SKIES EVERYWHERE WILL BE IN THE GRIPS OF THE VERY
COLD AIRMASS. WILL LIKELY SEE SUBZERO READINGS IN THE MTN VALLEYS
AND POSSIBLY NEAR ZERO LOWS IN LOW AREAS ON THE PLAINS.
MONDAY STILLS LOOKS COLD WITH TEMPS SEVERAL DEGREES BELOW
AVERAGE. THROUGH THE DAY COULD SEE SKIES QUICKLY CLOUDING UP AGAIN
AS ANOTHER CLIPPER RACES SOUTH OUT OF THE MONTANA ROCKIES. COULD
SEE SNOW DEVELOPING IN THE NRN MTNS BY THE AFTERNOON AND POSSIBLY
ON THE PLAINS BY EVENING. WITH SO MUCH OCCURRING TO THIS POINT
WILL STOP FOR NOW.
AVIATION...SOUTHEAST WINDS TO WEAKEN ACROSS THE AREA AND BECOME
SOUTHERLY AS DRAINAGE FLOW DEVELOPS. THE DIRECTION WILL BE MORE
WESTERLY AT BJC AS DOWNSLOPE PREVAILS. SPEEDS OF AROUND 8 KTS TO
PREVAIL...THOUGH SOME GUSTS TO 20 KTS WILL BE POSSIBLE AT BJC
BETWEEN 08Z AND 16Z. BY 18Z WINDS TO BECOME NORTHWESTERLY AND
SHOULD CONTINUE THROUGH THE AFTERNOON. VFR TO PREVAIL WITH A
GRADUAL INCREASE IN MID AND HIGH LEVEL MOISTURE. CEILINGS TO
REMAIN UNLIMITED.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....BAKER
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
341 PM MST WED DEC 5 2012
.SHORT TERM...MODERATE WESTERLY FLOW CURRENTLY ALOFT ACROSS
COLORADO WITH DECENT PRESSURE FALLS AHEAD OF APPROACHING MID LEVEL
TROUGH. WINDS A BIT GUSTY ACROSS MOUNTAINS AND FOOTHILLS AS WELL
AS WESTERN SECTIONS OF URBAN CORRIDOR. 1500M GJT-DEN PRESSURE
GRADIENTS CURRENTLY AT 8.09 MB...HAS BEEN INCREASING SINCE 20Z.
LATEST RUC CROSS SECTIONS SHOWING CROSS MOUNTAIN FLOW 55 KTS AT
MOUNTAIN TOP THROUGH 02Z THEN DECREASING TO AROUND 40 KTS BY 04Z.
SO WINDS TO REMAIN GUSTY INTO THE EVENING HOURS ESPECIALLY ACROSS
MOUNTAINS AND ALONG FOOTHILLS...BEFORE DECREASING DURING THE
EVENING. OTHERWISE...MOISTURE TO CONTINUE TO INCREASE THROUGH THE
EVENING AS TROUGH MOVES INTO THE GREAT BASIN. THE DEEPER AND MORE
SUBSTANTIAL MOISTURE WILL BEGIN ADVECTING INTO THE MOUNTAINS AFTER
00Z. COMBINATION OF SOME COLDER AIR ALOFT AND INCREASING LIFT
WILL HELP WITH PRECIPITATION DEVELOPMENT ACROSS MOUNTAINS.
POTENTIAL FOR SOME BANDED PRECIPITATION ACROSS THE NORTHERN
MOUNTAINS AFTER MIDNIGHT...WILL KEEP THE HIGHER POPS THERE. SYSTEM
INITIALLY FAIRLY WARM...SO SNOW ACCUMULATIONS TO BE LIGHT. ACROSS
PLAINS...STILL SOME THREAT FOR LIGHT RAIN NEAR THE WYOMING BORDER
WHERE SOME BANDED PRECIP COULD OCCUR. OTHERWISE...THINGS LOOK DRY
OVERNIGHT. MODELS STILL SHOWING WEAK FRONT MOVING ACROSS AREA
AFTER MIDNIGHT WITH WINDS SHIFTING TO THE NORTH. SOME WEAK UPSLOPE
TO DEVELOP BEHIND FRONT...THOUGH 12Z MODEL CROSS SECTIONS SHOW
FAIRLY DRY LOW LEVELS. ON THURSDAY...MODEL CROSS SECTIONS SHOW
DECENT MOUNTAIN OROGRAPHICS WITH GOOD MOISTURE. THOUGH MOST OF THE
LIFT MOVES ACROSS WYOMING...THERE IS ENOUGH LIFT ACROSS THE
MOUNTAINS DURING THE MORNING TO HELP WITH SNOWFALL. THE LIKELY
POPS STILL LOOKING REASONABLE WITH UP TO 2 INCHES POSSIBLE...
MAINLY WEST FACING SLOPES. BY AFTERNOON...MODELS SHOW OROGRAPHICS
WEAKENING AS LIFT MOVES EAST OF THE AREA...SO SNOW CHANCES TO
DECREASE DURING THE AFTERNOON. ACROSS PLAINS...LIFT TO MOVE ACROSS
AREA DURING THE MORNING AS WEAK UPSLOPE CONTINUES. COULD SEE SOME
PRECIPITATION THROUGH 18Z...THOUGH LIFT AND UPSLOPE NOT VERY
IMPRESSIVE. LATEST MODELS CONTINUE TO SHOW SOME LIGHT QPF...SEEMS
TO BE OVERDONE. ALSO TEMPERATURES LOOK TO BE WARM ENOUGH FOR
RAIN...EXCEPT PERHAPS ALONG PALMER DIVIDE AND CHEYENNE RIDGE.
AFTER 18Z LIFT IS EAST OF AREA WITH SUBSIDENCE OVERHEAD. THIS
SHOULD NEGATE ANY PRECIP CHANCES. COOLER AIRMASS WILL BE OVER AREA
WITH TEMPERATURES ROUGHLY 15 TO 20 DEGREES COLDER THAN TODAY`S
READINGS ACROSS PLAINS WITH HIGHS IN THE UPPER 40S AND LOWER 5OS.
THIS IS STILL ABOVE NORMAL.
.LONG TERM...A WEST-NORTHWEST FLOW ALOFT WILL PREVAIL THURSDAY
NIGHT THROUGH SATURDAY. MOISTURE EMBEDDED IN THE FLOW ALOFT WILL
BRING SOME LIGHT OROGRAPHIC SNOW TO THE MOUNTAINS AT TIMES
THURSDAY NIGHT THROUGH FRIDAY NIGHT. LAPSE RATES ARE JUST ALRIGHT
AT 5-7 C/KM...SO EXPECT SNOWFALL AMOUNTS TO STAY ON THE LIGHT
SIDE. A COLD FRONT WILL PUSH SOUTH ACROSS EASTERN COLORADO FRIDAY.
THIS WILL LOWER TEMPERATURES ANOTHER 5-10 DEGREES FROM THURSDAYS
HIGHS.
MOISTURE WILL INCREASE LATE FRIDAY NIGHT AND SATURDAY AS AN UPPER
LEVEL TROUGH MOVES SOUTHEAST OVER THE UTAH WYOMING AREA. EXPECT
SNOW TO INCREASE SATURDAY OVER THE MOUNTAINS. AT THE SURFACE...A
STRONG COLD FRONT WILL DROP SOUTH ACROSS EASTERN COLORADO SATURDAY
AFTERNOON. THIS WILL BRING GUSTY NORTHERLY WINDS BEHIND. AS
UPSLOPE WINDS AND MOISTURE SET UP EXPECT SNOW TO START SATURDAY
AFTERNOON OR EVENING. THE UPPER LEVEL TROUGH AXIS WILL PASS OVER
COLORADO SATURDAY NIGHT. DOWNWARD MOTION BEHIND THE TROUGH WILL
BRING THE SNOW TO AN END LATE SATURDAY NIGHT OR SNOW MORNING.
MOST OF THE MODELS SHOW IT WILL DRY OUT QUICKLY BEHIND THE FRONT
ON SUNDAY. WILL KEEP LOW POPS IN FOR THE EARLY PART OF THE SUNDAY
FOR THE POSSIBLILITY OF LINGERING SNOW. IF THE CLOUDS CLEAR OUT
SUNDAY NIGHT IT MAY GET QUITE COLD AND BE THE COLDEST NIGHT SO
FAR THIS SEASON.
FOR EARLY NEXT WEEK...AN ACTIVE NORTHWEST FLOW ALOFT WILL
PREVAIL. WEAK DISTURBANCES WILL PASS OVER THE STATE IN THIS
PATTERN. LITTLE TOO EARLY TO GET A GOOD TIMING ON THESE
SYSTEMS...SO WILL BROADDRUSH LOW POPS FOR THE MOUNTAINS. AT THIS
TIME...IT APPEARS THESE WAVES WILL BE TOO WEAK TO BRING SNOW TO
THE FRONT RANGE AND WILL KEEP THE MENTION OF SNOW OUT OF THE
FORECAST. TEMPERATURES WILL REMAIN NEAR TO BELOW NORMAL EARLY NEXT
WEEK. WOULD EXPECT WINDY CONDITIONS AT TIMES ALONG THE EAST
SLOPES UNDER THIS PATTERN.
&&
.AVIATION...WINDS TO REMAIN GUSTY THROUGH 02Z WITH GUSTS TO 20
KTS POSSIBLE AT DEN AND APA...AND UP TO 30 KTS AT BJC. WINDS TO
CONTINUE TO SHIFT TO THE NORTHWEST. AFTER 02Z WINDS TO WEAKEN AS
GRADIENT WEAKENS THOUGH MAY STILL BE A BIT GUSTY AT BJC. WEAK
FRONT TO MOVE ACROSS THE PLAINS AFTER 06Z WITH WINDS BECOMING
NORTHEAST. CEILINGS TO LOWER TO AROUND 6000 FEET AGL BY 12Z WITH A
SLIGHT CHANCE OF LIGHT RAIN. CONDITIONS WILL REMAIN VFR ALTHOUGH
ILS CONDITIONS POSSIBLE DUE TO CEILINGS. CONDITIONS TO IMPROVE BY
18Z WITH LIGHT EAST TO SOUTHEAST WINDS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....MEIER
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1012 AM MST WED DEC 5 2012
.UPDATE...
ISSUED AT 1008 AM MST WED DEC 5 2012
12Z NAM GUIDANCE SHOWING MUCH LESS PRECIP ACROSS FORECAST AREA
WITH THIS NEXT LITTLE DISTURBANCE EXCEPT FOR THE FLATTOPS AND
MOUNTAINS SURROUNDING STEAMBOAT SPRINGS. GFS SHOWS MORE AREAL
COVERAGE...TO INCLUDE UNCOMPAHGRE PLATEAU...BUT MUCH LESS QPF
AMOUNTS. HRRR AND EC ALSO FOLLOWING SUIT SO LOWERED POPS WITH THIS
UPDATE TO EXTREME NRN ZONES TODAY WITH ONSET OF PROLONGED PRECIP
STARTING AROUND 03Z THIS EVENING FOR THOSE AREAS MENTIONED ABOVE.
SNOWFALL AMOUNTS OF 2 TO 4 INCHES AT HIGHER ELEVATIONS WILL BE
COMMON FOR THE NORTHERN MOUNTAINS/FLATTOPS WHILE 1 TO 3 IS
EXPECTED FOR CENTRAL MOUNTAINS.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 300 AM MST WED DEC 5 2012
THE BEGINNING OF A PATTERN CHANGE STARTS TODAY AS THE UPPER LEVEL
LOW THAT HAS BEEN POSITIONED JUST OFF THE PACNW/B.C. COAST FOR QUITE
SOME TIME IS FINALLY PROGRESSING ACROSS CANADA THIS AFTERNOON. THIS
WILL PUSH ANOTHER PIECE OF ENERGY ACROSS OUR CWA THIS EVENING INTO
THURSDAY AFTERNOON. THIS MORNING WILL SEE SOME BREAKS IN THE CLOUD
COVER AS LOW LEVELS START OFF DRY...BUT THIS WILL ALL CHANGE THIS
AFTERNOON THROUGH THE EVENING AS CLOUDS INCREASE FROM THE
WEST...THICKEN AND LOWER AHEAD OF THE APPROACHING DISTURBANCE.
AFTERNOON TEMPERATURES WILL BE WARMER THAN YESTERDAYS WITH ABOVE
NORMAL READINGS IN THE MILD SOUTHWEST FLOW OUT AHEAD OF THE
APPROACHING DISTURBANCE.
THIS DISTURBANCE WILL BE MORE ROBUST THAN THE PAST FEW WEAK WAVES
THAT WERE EJECTED FROM THE PREVIOUSLY STATIONARY UPPER LOW. PLENTY
OF MOISTURE WILL BE IN PLACE WITH SPECIFIC HUMIDITIES IN THE 3.5 TO
4.0 G/KG RANGE AND SUFFICIENT SATURATION THROUGH THE DENDRITIC
LAYER...WHICH ACCORDING TO TIME HEIGHTS IS WELL ABOVE MOUNTAIN TOP
LEVEL AT AROUND 550MB OR 16.5KFT. TEMPS AT 700MB OR MOUNTAIN TOP
LEVEL IS AROUND -4C ACROSS THE NORTHERN MTNS AND AROUND 0C ACROSS
THE CENTRAL MTNS. THIS PUTS SNOW LEVELS AT AROUND 7 OR 8KFT. 700MB
WINDS WILL BE OUT OF THE WSW AT 25 TO 30 KTS MAINLY ACROSS THE
NORTHERN AND CENTRAL AREAS...SO THIS WILL FAVOR WEST-FACING SLOPES.
ISENTROPIC UPGLIDE IS EVIDENT AS WELL AS OMEGA WITH BETTER LIFT
ACROSS THE NORTHERN MOUNTAINS THAN THE CENTRAL MOUNTAINS. THE BEST
FORCING LOOKS TO OCCUR BETWEEN 09Z AND 15Z...RIGHT ON EITHER SIDE OF
SUNRISE THURSDAY MORNING. WHAT THIS ALL AMOUNTS TO IS ABOUT 3 TO 6
OVER THE FLATTOPS...ELKHEADS...AND PARK RANGES...WITH 2 TO 4 OVER
THE GRAND MESA. THESE AREAS LOOK FAVORED FOR BEST SNOW ACCUMS WITH
THE REST OF THE MOUNTAINS ABOVE 7 TO 8KFT RECEIVING 1 TO 3. LIGHT
RAIN SHOWERS ARE EXPECTED IN SOME NORTHERN AND CENTRAL VALLEYS WITH
SOME SNOW MIXING IN BUT NOT AMOUNTING TO MUCH AS THE GROUND IS
STILL FAIRLY WARM DUE TO RECENT ABOVE NORMAL TEMPS. INCREASED CLOUD
COVER SHOULD HELP TO KEEP TEMPS ABOVE FREEZING IN THE LOWER VALLEYS
TONIGHT.
BY THURSDAY AFTERNOON...SKIES WILL STILL REMAIN FAIRLY CLOUDY AS A
MOIST WESTERLY FLOW STAYS ON TOP OF US WITH SOME OROGRAPHIC SNOW
SHOWERS LIMITED TO THE HIGHER TERRAIN IN WESTERN COLORADO CLOSER AND
ALONG THE DIVIDE. TEMPERATURES WILL BE COOLER AND WILL NOT RECOVER
MUCH WITH A COOLING TREND EVIDENT AS THAT AIR FILTERS IN FROM THE
NORTHWEST THROUGH THE DAY. MORE DISCUSSION ON THIS IN THE LONG TERM
DISCUSSION BELOW.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 300 AM MST WED DEC 5 2012
MOIST WESTERLY FLOW WILL CONTINUE OVER THE REGION WITH SNOW
SHOWERS LINGERING OVER THE NORTHERN MOUNTAINS THROUGH FRIDAY. WITH
THE PERSISTENT NATURE OF THE SNOW SHOWERS...MAY SEE A FEW INCHES
OF ACCUMULATIONS THURSDAY NIGHT AND AGAIN FRIDAY...BUT BELOW
HIGHLIGHT CRITERIA. FOCUS WILL GENERALLY BE FROM VAIL PASS
NORTHWARD...WITH THE FLAT TOPS...PARK AND GORE RANGES FAVORED.
RISING HEIGHTS OFF THE WEST COAST WILL EVENTUALLY OPEN THE DOOR
FOR A MUCH COLDER SYSTEM TO SLIDE SOUTHEAST OUT OF SOUTHERN
ALASKA. THE NEW 00Z RUNS OF THE GFS AND ECMWF HAVE FLOPPED AGAIN
SHOWING A MORE PROGRESSIVE AND EVENTUALLY WEAK SYSTEM LATE
SATURDAY AND SUNDAY VERSUS DIGGING THE SYSTEM INTO THE SOUTHERN
GREAT BASIN. IN EITHER CASE...THE TREND IS TOWARD MUCH COOLER
WEATHER WITH MOUNTAIN SNOWFALL LIKELY TO CONTINUE THROUGH THE
WEEKEND...IN MOIST W AND EVENTUALLY NW FLOW. BEST FORCING ARRIVES
WITH THE COLDER AIR SATURDAY NIGHT AND EARLY SUNDAY AND THIS WOULD
BE THE TIMEFRAME FOR ANY POTENTIAL HIGHLIGHTS.
ANOTHER WAVE EJECTS OUT OF THE GULF ON MONDAY...BRINGING ANOTHER
CHANCE OF SNOW TO THE REGION BY TUESDAY...ALONG WITH A REINFORCING
SHOT OF COLDER AIR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z NOON THURSDAY)
ISSUED AT 300 AM MST WED DEC 5 2012
SCATTERED TO BROKEN SKIES WILL CONTINUE TODAY THOUGH THEY WILL
BECOME PREDOMINATELY BROKEN TO OVERCAST AS THE DAY TURNS INTO
EVENING. THESE CLOUDS WILL VFR HOWEVER SO NO OPERATIONAL IMPACTS
ARE EXPECTED AT ANY AERODROMES. BY 06Z HOWEVER...AREAS NORTH OF
I-70 WILL SEE TIMES OF MVFR AND IFR UNDER HEAVIER RAIN/SNOW
SHOWERS AS VIS AND CIGS DROP. KVEL...KEGE...AND KASE WILL BE UNDER
THE GUN TONIGHT FOR THESE IFR CONDITIONS. CONDITIONS WILL IMPROVE
FROM 18Z ONWARDS TOMORROW.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...TGR
LONG TERM...JDC
AVIATION...TGR
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1037 PM MST TUE DEC 4 2012
.UPDATE...
ISSUED AT 923 PM MST TUE DEC 4 2012
LATEST HRRR AND RAP MODEL DATA INDICATE THAT SOME LIGHT SNOW
SHOWERS WILL OCCUR MAINLY BETWEEN 06Z AND 12Z IN UTZ023 AND
COZ004...PARTICULARLY THE ELKHEADS...WHILE THE REST OF THE
NORTHERN MOUNTAINS WILL BE LIMITED TO SOME FLURRIES AT THE
HIGHEST PEAKS. NOT ENOUGH FORCING EVIDENT TO WARRANT A MENTION OF
POPS IN THE FLATTOPS OR OTHER SUBSEQUENT ZONES...SO REMOVED
MENTION OF POPS IN ALL BUT UTZ023 AND COZ004 TONIGHT. THE REST OF
THE FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 335 PM MST TUE DEC 4 2012
AN UPPER LOW REMAINS OFF THE WEST COAST OF CANADA AND CONTINUES TO
DIRECT A STEADY STREAM OF PACIFIC MOISTURE AND EMBEDDED DISTURBANCES
INLAND. ERN UT/WRN CO WERE BETWEEN WEAK DISTURBANCES THIS AFTERNOON
FOR PARTLY SUNNY SKIES. AN AREA OF MAINLY LIGHT PRECIPITATION
PERSISTED ACROSS PARTS OF NE NV/SRN ID/NW UT THIS AFTERNOON.
CLOUDS WILL THICKEN AGAIN TONIGHT AS THE NEXT WAVE REACHES THE AREA.
WILL CARRY A LOW-END CHANCE OF SNOW FOR THE ERN UINTAS/FLATTOPS/
PARK/ELKHEAD MTNS LATE TONIGHT WITH THE PASSAGE OF THIS NEXT
WAVE...BUT WITH 700 MB FORECAST WARMING ABOVE FREEZING... SNOW
LEVELS WILL BE HIGH. CLOUDS TONIGHT WILL KEEP LOW TEMPS WARMER THAN
LAST NIGHT.
A BETTER CHANCE OF PRECIPITATION ARRIVES WEDNESDAY NIGHT AS A BETTER
DEFINED BUT WEAKENING WAVE APPROACHES. MAY SEE A BIT OF A BREAK
IN CLOUDS LATER WED MORNING BETWEEN DISTURBANCES AGAIN...BUT THEN
CLOUDS INCREASING FROM THE WEST WED AFTERNOON. ISENTROPIC ANALYSIS
REVEALED THE DEEPER RIBBON OF MOISTURE SLIDING OVER NE UT/NW CO WED
EVENING IN NEUTRAL TO WARM ADVECTION FOR AN INCREASING CHANCE OF
PRECIPITATION WED EVENING. 700 MB WINDS REMAIN WEST-SOUTHWEST MOST
OF WED NIGHT AND NOT THE BEST FOR OROGRAPHIC FORCING IN THE MTNS
AROUND STEAMBOAT SPRINGS...BUT ENOUGH MOISTURE AND Q-G FORCING LOOK
PRESENT FOR 1-4 INCHES OF NEW SNOW ACROSS THE NORTHERN CO MTNS
AFTER MIDNIGHT WED NIGHT...WITH A CHANCE OF SNOW IN THE CENTRAL
MTNS. THE EASTERN UINTA MTNS LOOK TO REMAIN SHADOWED BY THE HIGHER
MTNS TO THEIR WEST. A CHANCE OF RAIN OR RAIN/SNOW FOR THE CENTRAL
AND NORTHERN VALLEYS WED NIGHT AS CLOUDS HELP LOW TEMPS STAY ABOVE
NORMAL.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 335 PM MST TUE DEC 4 2012
THE PERSISTENT AREA OF LOW PRESSURE HANGING IN THE NORTHEAST
PACIFIC/GULF OF ALASKA THE PAST FEW WEEKS WILL BE REPLACED BY
RIDGING BEGINNING THURSDAY AND LASTING THROUGH EARLY NEXT WEEK.
THIS PATTERN CHANGE WILL TRANSLATE TO A MORE STORMY PATTERN OVER
THE CENTRAL ROCKIES WITH A MUCH COOLER AIRMASS ARRIVING TO OUR CWA
MID WEEKEND INTO EARLY NEXT WEEK. THERE ARE STILL DETAILS TO BE
WORKED OUT BUT THERE APPEARS TO BE A GOOD CHANCE THAT THE COLORADO
MOUNTAINS WILL BE RECEIVING SOME MUCH NEEDED SNOWFALL AS WINTER
LIKE WEATHER RETURNS AND POSSIBLY LINGERS THROUGH MUCH OF NEXT
WEEK.
THE WEAKENING SYSTEM WED NIGHT INTO THURSDAY STILL HAS A DECENT TAP
TO THE RICH MOISTURE SOURCE CURRENTLY POUNDING THE WEST COAST.
MIXING RATIOS NEAR THE 4G/KG RANGE WILL BE TRANSPORTED INTO
NORTHERN COLORADO PER THETA SURFACES AROUND 300K BY THURSDAY
MORNING. MAXIMIZED LARGE SCALE ASCENT WILL BE CROSSING THE
NORTHERN COLORADO BORDER BY SUNRISE AHEAD OF THE MAIN SHORT WAVE
ENERGY...AND LOOKS TO BE ENHANCED BY A COUPLED JET STRUCTURE.
THEREFORE THE HIGH POPS OVER THE NORTHERN MOUNTAINS EARLY IN THE
DAY LOOK ON TRACK AND ONLY MADE A FEW TWEAKS. LIFT AND SATURATION
THROUGH THE DENDRITIC LAYER WILL DECREASE THROUGH THE DAY BUT WEAK
INSTABILITY AND OROGRAPHICS SHOULD KEEP SOME SHOWERS GOING THROUGH
SUNSET AS THE HIGH COUNTRY LOOKS TO REMAIN MOIST. H7 TEMPS NOT ALL
THAT COLD BEHIND WAVE BUT MAY SEE A FEW SNOW SHOWERS IN THE HIGH
VALLEYS WITH ANOTHER 1-3 INCHES POSSIBLE ON WEST FACING SLOPES OF
HIGHER PEAKS. TEMPERATURES LOOK TO FALL OFF AROUND 5 TO 7 DEGREES.
THURSDAY NIGHT INTO FRIDAY THINGS AGAIN LOOK INTERESTING AS A
VIGOROUS WAVE DIVES OUT OF THE NORTHWEST INTO THE NORTHERN ROCKIES.
MODEL CONSENSUS HOWEVER IS LESS THAN PERFECT WITH NATIONAL GUIDANCE
LEANING TOWARD A MORE DAMPED WAVE PATTERN LIKE THE EURO. NAM SLIDES
CLOSER TO THE THIS SOLN WITH THE GFS DIGGING THE STRONGEST ENERGY
OVER NORTHERN COLORADO BY FRIDAY MORNING. FOR NOW HAVE DECREASING
PRECIPITATION TREND EARLY IN THE OVERNIGHT PERIOD WITH LOSS OF
INSTABILITY AND THE MOISTURE TAP BEING FORCED SOUTHWARD. THEN LIFT
SHOULD INCREASE AFTER MIDNIGHT AS THE WAVE BRUSHES BY TO THE
NORTH AND MOIST WESTERLY FLOW BEGINS OROGRAPHIC SHOWERS IN THE
NORTHERN MOUNTAINS. THE NAM DOES SHOW A SHALLOW FRONT MOVING INTO
THE NORTHWEST ZONES UNDER A WEAK MID LEVEL FRONTO BAND...BUT DEEP
LIFT IS LACKING WITH JET AND MAIN FORCING FARTHER NORTH. GFS HAS
THESE FEATURES COMING TOGETHER FOR THE FAR NORTHERN ZONES AND
PRODUCES SOME BRIEF MODERATE TO HEAVY SNOW. THIS SOLUTION IGNORED
AS AN OUTLIER ATTM BUT SHOULD BE MONITORED FOR TRENDS. SIDING
OUTSIDE THE GFS...DRIER AIR MOVES IN FRIDAY AFTERNOON ALONG WITH
WEAK SUBSIDENCE LEAVING ONLY SOME LIGHT OROGRAPHIC SHOWERS
POSSIBLE IN THE NORTHERN AND CENTRAL MOUNTAINS THAT ARE FAVORED IN
NW FLOW. AFTERNOON TEMPERATURES AGAIN LOOK TO TAKE ANOTHER HIT
AROUND 5 DEGREES.
THE BIG CHANGES COME SATURDAY AS THE MAIN PORTION OF THE REMNANT
PACIFIC LOW DIGS INTO THE GREAT BASIN BY AN AMPLIFYING RIDGE ALONG
THE WEST COAST. THIS ENERGY IN CONJUNCTION WITH THE POLAR VORTEX WILL
SEND A SHOT OF THE COLDEST AIR OF THE SEASON SOUTHWARD AND SPREAD
SNOWFALL ACROSS THE EASTERN UTAH AND WESTERN COLORADO MOUNTAINS.
AGAIN THIS FAR OUT MODEL CONSENSUS IS TIGHTENING NOW THAT THE GFS HAS
FLOPPED BACK TOWARD IT/S 00Z FORECAST...AND NOW CLOSER RESEMBLES
THE EURO...BUT AGAIN IT WILL BE IMPORTANT TO WATCH THESE TRENDS.
FOR NOW LARGE SCALE ASCENT IS MAXIMIZED IN THE SATURDAY MORNING TO
SUNDAY MORNING TIME FRAME WITH THE GFS ON THE EARLY SIDE. THIS
LIFT WILL BE ENHANCED BY THE STRONG COLD FRONT AND POSSIBLY SOME
DECENT POTENTIAL INSTABILITY...DEPENDING ON THE UPPER TROF
LOCATION. THE BIGGEST CONCERN NOW IS MOISTURE AVAILABILITY BUT
THE VERY COLD AIR SHOULD MAKE SNOW PRODUCTION MORE EFFICIENT. FOR
NOW THE OUTLOOK SHOWS SOME CLEARING SUNDAY NIGHT INTO MONDAY AS
THE SYSTEM SHIFT SOUTHEASTWARD. THE TEMPERATURE REGIME WILL BE
WELL BELOW NORMAL SUNDAY INTO EARLY NEXT WEEK WITH ANOTHER SHOT OF
SNOW POSSIBLE MONDAY NIGHT INTO TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1033 PM MST TUE DEC 4 2012
VFR CONDITIONS WILL CONTINUE AT ALL TAF SITES THROUGH WEDNESDAY
EVENING UNDER MOIST WESTERLY FLOW ALOFT. CLOUDS WILL LOWER ACROSS
THE NORTH WITH AREAS OF MVFR CIGS AND LOCAL -SN POSSIBLE OVER THE
NORTHERN MTNS BETWEEN THROUGH 15Z WED.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...MDA
SHORT TERM...JAD
LONG TERM...15
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
923 PM MST TUE DEC 4 2012
.UPDATE...
&&
.SHORT TERM...SFC PRESSURE ACROSS NERN COLORADO CONTINUED TO FALL
SLOWLY THIS EVENING. AS OF 03Z THE DEN-GJT 1500METER PRESSURE
GRADIENT HAD INCREASED TO 6.35 MBS. MODELS CONTINUE THIS TREND
THE NEXT FEW HRS BEFORE REVERSING AFTER MIDNIGHT AS RADIATIONAL
COOLING ON THE PLAINS LEADS TO RISING PRESSURES. RUC AND NAM CROSS
SECTIONS SHOW A GRADUAL INCREASE IN THE WESTERLY WIND COMPONENT
AT MTN TOP LEVEL THROUGH THE NIGHT...PEAKING AROUND 35KT AS OF
12Z/WED. MAY SEE WEST WINDS GUSTING 35-40 MPH ON THE RIDGETOPS
AND CANYONS OF THE FRONT RANGE...AND 25-35 MPH OCCASIONALLY NEAR
THE BASE OF THE FOOTHILLS IN NORTHERN JEFFERSON...BOULDER...
LARIMER COUNTIES. OTHERWISE MID AND HIGH LEVEL MOISTURE PASSING
THROUGH THE MTN WAVE WILL ALSO PRODUCE PERIODS OF MTN WAVE CLOUDS
OVER AND ALONG THE FRONT RANGE. THE DOWNSLOPE BREEZES AND THE
CLOUD COVER WILL HELP TO HOLD MIN TEMPS UP ALONG THE BASE OF THE
FOOTHILLS.
.AVIATION...VFR CONDITIONS AND LIGHT DRAINAGE WINDS UNDER 12KTS
EXPECTED AT DENVER AREA AIRPORTS OVERNIGHT. WILL ALSO SEE OF
PERIODS OF MID AND HIGH MTN WAVE CLOUDINESS OVER THE METRO AREA
THROUGH THE NIGHT. BJC NEAR THE BASE OF THE FOOTHILLS COULD SEE
WEST WINDS GUSTING OCCASIONALLY 25-35 MPH.
&&
.PREV DISCUSSION... /ISSUED 350 PM MST TUE DEC 4 2012/
SHORT TERM...MODERATE WEST TO NORTHWEST FLOW ALOFT ACROSS REGION
WITH SHORT WAVE RIDGE OVER GREAT BASIN. WEAK STABLE LAYER
CURRENTLY AT MOUNTAIN TOP WITH RADAR SHOWING SOME SIGNS OF A
MOUNTAIN WAVE. WINDS ALOFT NOT VERY STRONG WITH CROSS MOUNTAIN
FLOW 30-35 KTS AT MOUNTAIN TOP. SOME RECENT GUSTS TO 40 MPH BEING
REPORTED IN THE ESTES PARK AREA...BUT APPEAR LOCALIZED AND PERHAPS
TERRAIN DRIVEN. LATEST RUC CROSS SECTIONS INDICATE WINDS ALOFT
GRADUALLY DECREASING AFTER 02Z WITH CROSS MOUNTAIN WINDS AROUND 25
KTS NEAR RIDGE TOP AND ALONG HIGHER FOOTHILLS BY 06Z. THUS SHOULD
SEE WIND GUSTS GRADUALLY DECREASE DURING THE EVENING THOUGH THE
TERRAIN MAY KEEP THINGS A BIT GUSTY. SHOULD ALSO SEE A GRADUAL
INCREASE IN HUMIDITY AS TEMPERATURES COOL. LATEST SATELLITE LOOPS
SHOW CLOUDS HAVE THINNED ACROSS THE AREA WITH REMNANTS OF WAVE
CLOUD EAST OF URBAN CORRIDOR. MORE MOISTURE UPSTREAM...WITH
INCREASING HIGH LEVEL MOISTURE OVERNIGHT. WRF SYNTHETIC SATELLITE
IMAGERY SUGGESTING THE WAVE CLOUD REDEVELOPS ALONG FOOTHILLS AFTER
08Z. ON WEDNESDAY...FLOW ALOFT BECOMES WESTERLY AS RIDGE MOVES
SOUTH AND EAST OF COLORADO. CROSS SECTIONS SHOW MOISTURE
INCREASING ACROSS THE AREA WITH SOME LOWERING OF THE MOISTURE
ACROSS MOUNTAINS DURING THE MORNING...MAINLY NORTH OF INTERSTATE
70. MAY BE ENOUGH OROGRAPHICS TO GENERATE SOME SHOWERS ACROSS ZONE
31. OTHERWISE WINDS ALOFT TO INCREASE WITH CROSS MOUNTAIN FLOW AROUND
40 KTS AT MOUNTAIN TOP BY 18Z. THUS WINDS TO BE GUSTY ACROSS THE
MOUNTAINS AND HIGHER FOOTHILLS WITH LOCAL GUSTS AROUND 45 MPH
POSSIBLE DURING THE AFTERNOON. THE GUSTY WINDS WILL KEEP THE FIRE
DANGER ELEVATED ALONG THE FOOTHILLS...BUT HUMIDITY SHOULD REMAIN
ABOVE CRITICAL FIRE WEATHER THRESHOLDS. TEMPERATURE AND THICKNESS
PROGS AS WELL AS GUIDANCE SHOWING HIGHS IN THE 60S ACROSS THE
PLAINS. THIS LOOKING REASONABLE. CURRENT TEMPERATURE GRIDS IN LINE
WITH GUIDANCE...ONLY MINOR CHANGES NEEDED.
LONG TERM...WESTERLY FLOW ALOFT WILL PREVAIL WEDNESDAY NIGHT AND
THURSDAY. WINDS WILL INCREASE WEDNESDAY NIGHT OVER THE MOUNTAINS AND
FOOTHILLS AS A COLD FRONT MOVES THROUGH THE STATE. A WEAK SHORT
WAVE TROUGH MAY BRING LIGHT SNOW TO THE MOUNTAINS AND PERHAPS SOME
LIGHT RAIN OVER EASTERN COLORADO THURSDAY.
THE WESTERLY JET WILL SINK SOUTH AS AN UPPER LEVEL TROUGH MOVES ONTO
THE PACIFIC NORTHWEST COAST. THIS WILL BRING COOLER CONDITIONS ON
FRIDAY WITH HIGHS IN THE 40S. ANOTHER WEAK DISTURBANCE EMBEDDED IN
THE FLOW ALOFT WILL BRING ANOTHER CHANCE FOR LIGHT PRECIPITATION.
THE UPPER LEVEL TROUGH OVER THE PACIFIC NORTHWEST WILL DIVE SOUTH
ACROSS THE GREAT BASIN SATURDAY AND END UP OVER THE SOUTHERN ROCKIES
SUNDAY. THIS WILL PUSH A STRONG COLD FRONT ACROSS COLORADO. STILL
SOME DIFFERENCE ON TRACK AND TIMING...BUT WILL BE ENOUGH ENERGY TO
BRING A PERIOD OF SNOW TO THE AREA. BIGGEST QUESTIONS ARE WHEN AND
HOW MUCH. APPEARS THE SNOW WILL BEGIN SOMETIME SATURDAY AND COME TO
AN END EARLY SUNDAY. MAY SEE SOME HEAVIER SNOW BANDS SATURDAY AS THE
JEST SINKS SOUTH ACROSS COLORADO. WILL CENTER THE HIGHEST POPS
AROUND SATURDAY NIGHT WHEN THE BEST CHANCE WILL BE ACCORDING TO THE
MODELS. COLD AIR WILL MOVE IN WITH THIS SYSTEM AND HIGHS WILL LIKELY
REMAIN BELOW FREEZING SUNDAY AND EARLY NEXT WEEK. NORTHWEST FLOW MAY
BRING LIGHT OROGRAPHIC SNOW EARLY NEXT WEEK...OTHERWISE JUST DRY AND
COOL CONDITIONS ARE EXPECTED FOR MONDAY AND TUESDAY.
AVIATION...LIGHT EASTERLY WINDS AT APA AND DEN TO WEAK AND BECOME
SOUTHERLY AS DRAINAGE PATTERN DEVELOPS. WINDS TO REMAIN WESTERLY
AT BJC. ON WEDNESDAY...WINDS TO BECOME NORTHWEST AFTER 18Z WITH
SPEEDS AROUND 8 KTS. HIGH LEVEL MOISTURE TO INCREASE AFTER 06Z
WITH THE POTENTIAL FOR A WAVE CLOUD ALONG FOOTHILLS BY 10Z. VFR TO
CONTINUE WITH CEILINGS UNLIMITED.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER/D_L
LONG TERM....MEIER
AVIATION...BAKER/D_L
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1025 AM EST WED DEC 5 2012
.DISCUSSION...
CURRENT...WEAK LOW LEVEL TROUGH WHICH WAS NOTED OVER THE ATLC IN THE
TUE AFTERNOON AFD PUSHED ONSHORE EARLY THIS MORNING...AND PRODUCED
DECENT AMOUNT OF SHOWER ACTIVITY ALONG COASTAL AREAS. THIS WEAK LOW
LEVEL FEATURE IS EVIDENT IN SFC METARS AND RUC LOW LEVEL (H925-H850)
WIND/VORT ANALYSES AND HAS PIVOTED NWWD AND IS LIFTING ACROSS THE
NRN CWA. WEAK LOW LEVEL CONVG/ASCENT ASCD WITH THIS FEATURE IS
PRODUCING QUITE BIT OF LOW TO MID LEVEL BKN-OVC CLOUDINESS FROM
OSCEOLA/BREVARD COUNTIES NORTHWARD AS THE MID LEVEL DECK "PANCAKES"
UNDERNEATH THE STILL STOUT CAP BETWEEN H80-H70. LATEST RADAR IMAGERY
SHOWS THAT PRECIP HAS PRETTY MUCH DISSIPATED OVER LAND AS IT MOVES
SLOWLY NW.
REST OF TODAY...LOCAL MESOMODEL GUIDANCE SHOWS THE WEAK TROUGH WILL
BE SLOW TO DAMPEN OUT THIS AFTERNOON...WHICH WOULD RESULT IN BROKEN
MID LEVEL CLOUD COVER PERSISTING ACROSS THE NORTHERN HALF CWA LONGER
THAN ADVERTISED...WHICH MAY ALSO RESULT IN MAX TEMPS A DEG OR SO
LOWER. SINCE BREAKUP OF THE LOW-MID CLOUDS IS EXPECTED TO TAKE A BIT
LONGER WILL GO AHEAD AND TWEAK SKY COVER AND TEMP GRIDS TOWARD THIS
END. WITH RESPECT TO POPS...WILL LIKELY TWEAK THEM DOWN TO 20 PCT
AWAY FROM THE CURRENT POSITION OF THE TROUGH.
&&
.AVIATION...STUBBORN IFR STRATUS DECK BKN-OVC004-007 STILL NOTED IN
METARS ALONG COASTAL VOLUSIA/NORTH BREVARD (OMN-DAB-EVB-TTS-TIX).
ALTHOUGH IT`S BEEN SLOW TO BREAK UP THUS FAR BECAUSE OF THE OVC-BKN
DECK ABOVE IT (6-7KFT) IT SHOULD DO SO SHORTLY VIA DIURNAL HEATING/
MIXING. WILL PROBABLY NEED TO HANG ON TO VFR CIGS BKN060-070 ALONG
/NORTH OF MLB-ISM INTO THIS AFTERNOON.
&&
.MARINE...WINDS CONTINUE TO DECREASE TODAY. ESE AROUND 10KT OR LESS
TODAY THROUGH TONIGHT. SEAS 3-5 FT IN LINGERING SWELL.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...CRISTALDI
LONG TERM/IMPACT WX....WEITLICH
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
335 AM EST WED DEC 5 2012
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOW A NORTHERN STREAM TROUGH
FRACTURE UNDERWAY ACROSS THE MIDDLE/SOUTHERN MS VALLEY EARLY THIS
MORNING. RESULTING DETACHED SHORTWAVE ON THE SOUTHERN PORTION OF THE
ORIGINAL TROUGH IS SLOWING TRANSLATING EAST AND SOUTHEASTWARD OVER
THE NORTHERN GULF OF MEXICO. UPPER LEVEL RIDGE THAT HAS BEEN
DOMINANT IN OUR WEATHER THE PAST SEVERAL DAYS IS STILL OVERHEAD...
BUT WILL BE REPLACED RAPIDLY DURING THE NEXT 6-12 HOURS BY
INCREASING CYCLONIC FLOW AHEAD OF THE SHORTWAVE. 05/00Z KTBW
SOUNDING PROFILE STILL SHOWED THE RIDGE INFLUENCE IN THE FORM OF A
WELL-DEFINED SUBSIDENCE INVERSION JUST ABOVE 800MB. WOULD EXPECT
THAT THIS LARGE SCALE SUBSIDENCE IS ALREADY WEAKENING OVER OUR HEADS
THIS MORNING...AND WILL BEGIN TO SEE A NEW PROFILE EMERGE WITH THE
12Z SOUNDING.
AT THE SURFACE...RIDGE OF HIGH PRESSURE CONTINUES TO EXTEND FROM
OFF THE SOUTHEAST COAST BACK TO SOUTHERN GA...BUT IS BEGINNING TO
WEAKEN AND BECOME LESS DEFINED IN RESPONSE TO THE APPROACH OF A
SURFACE COLD FRONT MOVING OUT OF THE TN VALLEY. ALTHOUGH THE RIDGE
IS WEAKENING...GRADIENT FLOW SOUTH OF THE AXIS CONTINUES TO PROVIDE
THE REGION WITH A LIGHT EASTERLY BOUNDARY LAYER WIND AND ABUNDANT
LOW LEVEL ATLANTIC MOISTURE. SKIES THIS MORNING ARE GENERALLY PARTLY
CLOUDY WITH AREAS OF 4-6KFT STRATOCU MOVING ACROSS THE PENINSULA
WITHIN LOW LEVEL FLOW.
&&
.SHORT TERM (TODAY - FRIDAY)...
TODAY...LARGE SCALE MID/UPPER LEVEL FLOW WILL BECOME INCREASINGLY
CYCLONIC IN NATURE THROUGH THE DAY WITH RESULTING WEAK SYNOPTIC
SUPPORT ALLOWING FOR ISOLATED/WIDELY SCT LIGHT SHOWER/SPRINKLE
DEVELOPMENT. OVERALL COLUMN MOISTURE WILL STILL NOT BE ALL THAT
IMPRESSIVE...BUT ENOUGH INGREDIENTS COMING TOGETHER TO SUPPORT A
SLIGHT CHANCE 20-30% CHANCE OF SHOWERS. THIS SOLUTION IS SHOWN BY
THE HI-RES CONVECTIVE ALLOWING GUIDANCE SUITE...AND SEE LITTLE
REASON TO ARGUE WITH THE CONSENSUS. BEST CHANCES FOR SHOWERS WILL
LIKELY BE ACROSS THE EASTERN HALF OF THE FORECAST AREA DURING THE
AFTERNOON ASSOCIATED WITH ACTIVITY MOVING INLAND FROM THE EAST
COAST. THE IMPACT OF ANY SHOWERS SHOULD BE MINIMAL...WITH VERY
LITTLE IN THE WAY OF RAINFALL ACCUMULATION FOR THOSE SPOTS THAT DO
SEE A BRIEF SHOWER. MORE IN THE WAY OF CLOUDS TODAY COMPARED TO
PREVIOUS DAYS...HOWEVER STILL EXPECT ENOUGH SUNNY BREAKS TO ALLOW
TEMPERATURES TO REACH WELL UP INTO THE 70S...AND PERHAPS NEAR 80 AT
WARMER LOCATIONS.
TONIGHT/THURSDAY...SHORTWAVE AXIS MOVES OVER THE EASTERN GULF OF
MEXICO OVERNIGHT AND THEN APPROACHES THE FL PENINSULA THURSDAY
MORNING. GFS/ECMWF SHOWING THE BEST ASSOCIATED QG FORCING/SYNOPTIC
SUPPORT COINCIDENT WITH DEEP LAYER MOISTURE COMING TOGETHER OVER THE
SOUTHERN HALF OF THE FL PENINSULA. WITH THIS IN MIND WILL KEEP THE
BEST SHOWER CHANCES (30-40%) TO THE SOUTH OF TAMPA BAY THROUGH THE
MORNING HOURS. AS THIS LARGE SCALE FORCING BEGINS TO PIVOT EASTWARD
LATER IN THE DAY...IT SHOULD FURTHER AID THE DEVELOPMENT OF SHOWERS
MOVING INLAND FROM THE EAST COAST. SOUTHERN AND EASTERN ZONES WILL
SHOW 30-40% POPS FOR THE AFTERNOON WITH 20% ISOLATED SHOWER CHANCES
FOR TAMPA BAY AND THE NATURE COAST ZONES. ONCE AGAIN...RAINFALL
AMOUNTS WILL GENERALLY BE LOW WITH ANY SHOWERS AND A DROUGHT BUSTER
THIS EVENT WILL NOT BE.
FRIDAY...SHORTWAVE ENERGY SHEARS OUT AND EXITS TO OUR EAST EARLY IN
THE DAY. THE MOVEMENT OF THIS ENERGY OVER THE GULF STREAM THURSDAY
NIGHT SHOULD ENHANCE THE DEVELOPMENT OF AN INVERTED SURFACE TROUGH
ALONG THE FL EAST COAST. HIGH PRESSURE WILL BE BUILDING TO OUR NORTH
BACK DOWN THE EASTERN SEABOARD DURING THIS TIME. INCREASING EASTERLY
LOW LEVEL FLOW SHOULD THEN HELP PUSH THIS SURFACE TROUGH SLOWLY BACK
TO THE WEST THROUGH THE DAY. SO...DESPITE THE LARGE SCALE SUBSIDENCE
OVERSPREADING THE REGION IN THE WAKE OF THE SHORTWAVE...THE LOW
LEVEL FOCUS ALONG THE INVERTED TROUGH AND INCREASING EASTERLY FLOW
SHOULD PROMOTE FURTHER SHALLOW SHOWER DEVELOPMENT ALONG THE FL EAST
COAST. AFTER A BREAK EARLY FRIDAY...WILL BRING ISOLATED SHOWER
MENTION ALONG THE WEST COAST AND SCT SHOWERS INLAND BACK INTO THE
FORECAST BY FRIDAY AFTERNOON.
&&
.LONG TERM (SATURDAY - NEXT TUESDAY)...
NO MAJOR PROBLEMS THROUGH THE WEEKEND AS SURFACE RIDGING CONTINUES
FROM THE ATLANTIC WESTWARD TO FLORIDA WHILE UPPER-LEVEL ENERGY
REMAINS TO OUR WEST. THERE WILL BE A FEW SHOWERS AROUND BOTH DAYS AS
A MOIST LOW-LEVEL SOUTHEASTERLY FLOW MOVES ACROSS THE HEATED
SURFACE. THE TRICKY PART OF THE FORECAST COMES DURING THE
MONDAY/TUESDAY TIMEFRAME WHEN MODELS START TO DISAGREE ON AN
APPROACHING UPPER-LEVEL TROUGH.
THE MODELS AS A WHOLE HAVE TRENDED A LITTLE FASTER/MORE PROGRESSIVE
WITH THE TROUGH WHICH RESULTS IN A FRONTAL PASSAGE LATE MONDAY OR ON
TUESDAY. THE GFS IS THE FASTER OF THE MODELS AND HAS THE FRONT
APPROACHING THE TAMPA BAY AREA MONDAY EVENING. THE EARLIER 12Z ECMWF
WAS MUCH SLOWER...BUT THE MORE RECENT 00Z RUN HAS SPLIT THE
DIFFERENCE NOW WITH THE FRONT REACHING TAMPA BAY TUESDAY MORNING.
THE 12 HOUR DIFFERENCE IN TIMING WILL RESULT IN SIGNIFICANT
DIFFERENCES IN WHEN THE BEST RAIN CHANCES WILL BE AND WHEN THE
COOLER AIR MOVES IN. HAVE LEANED MOST HEAVILY ON THE 00Z ECMWF BUT
DID BLEND THE GFS/MEX TEMPERATURES IN WHICH WERE COOLER THAN THE
ECMWF. HIGHEST RAIN CHANCES SHOULD BE CENTERED ON MONDAY NIGHT...
BUT THINK WE WILL SEE SOME SHOWERS AHEAD OF THE FRONT MONDAY.
SHOWERS SHOULD BEGIN TO TAPER OFF FROM NORTH TO SOUTH...AT LEAST
INITIALLY...BEHIND THE FRONT ON TUESDAY.
BOTH MODELS RAPIDLY HALT THE SOUTHWARD PROGRESSION OF THE FRONT
BEYOND DAY 7 AND SHOW THE POTENTIAL FOR SOME OVER-RUNNING RAINS FOR
THE MIDDLE TO END OF NEXT WEEK.
&&
.AVIATION...
MAINLY VFR NEXT 24 HOURS. SLIGHT CHANCE OF SOME EARLY MORNING PATCHY
FOG MAINLY NEAR PGD AND LAL BUT CONFIDENCE TOO LOW TO INCLUDE IN
TAFS AT THIS TIME.
&&
.MARINE...
HIGH PRESSURE TO THE NORTH OF THE REGION WILL WEAKEN TODAY AND
THURSDAY HELPING TO KEEP WINDS AND SEAS BELOW HEADLINE CRITERIA THE
NEXT SEVERAL DAYS. HIGH PRESSURE WILL ONCE AGAIN BUILD TO OUR NORTH
DURING THE UPCOMING WEEKEND...BUT SHOULD NOT BE STRONG ENOUGH TO
RESULT IN ANY SIGNIFICANT MARINE CONCERNS. THE NEXT COLD FRONT IS
ANTICIPATED TO ARRIVE OVER THE EASTERN GULF OF MEXICO DURING THE
EARLY PORTION OF NEXT WEEK.
&&
.FIRE WEATHER...
NO SIGNIFICANT FIRE WEATHER CONCERNS ARE ANTICIPATED THROUGH THE
REMAINDER OF THE WEEK. A GENERAL EASTERLY FLOW WILL CONTINUE TO
TRANSPORT ATLANTIC MOISTURE INTO THE REGION AND PREVENT CRITICAL
LEVELS OF RELATIVE HUMIDITY. ISOLATED TO WIDELY SCATTERED SHOWERS
WILL BE IN THE FORECAST THE NEXT SEVERAL DAYS...HOWEVER NO
SIGNIFICANT RAINFALL ACCUMULATIONS ARE EXPECTED.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 79 60 79 60 / 20 10 20 10
FMY 80 59 80 60 / 20 20 30 10
GIF 79 56 80 57 / 20 20 30 20
SRQ 78 59 79 61 / 10 10 20 10
BKV 79 55 80 55 / 20 10 20 10
SPG 77 63 77 62 / 10 10 20 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS DES MOINES IA
536 PM CST THU DEC 6 2012
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
WEAK SHORTWAVE WILL CONTINUE TO PUSH EAST OF THE FORECAST AREA LATE
THIS AFTERNOON INTO THE EARLY EVENING WHILE A SECOND SHORTWAVE WILL
MOVE ACROSS SOUTHERN IOWA/NORTHERN MISSOURI THROUGH 09Z FRIDAY.
WEAK BOUNDARY ASSOCIATED WITH THE FIRST SHORTWAVE LOOKS TO BE INTO
NORTHERN MISSOURI AND FAR SOUTHEAST IOWA BY 00Z FRIDAY. SLIGHTLY
BETTER FORCING WITH THE SECOND VORT MAX LOOKS TO BE CONFINED TO
SOUTHEAST IOWA. THIS IS EVIDENT ALONG THE 295K TO 305K ISENTROPIC
SURFACE WHICH COINCIDES TO THE WEAK THETA-E ADVECTION AOA 700MB.
BUFR SOUNDINGS SATURATED ABOVE 700MB SO PRECIP WILL BE HIGH BASED
THIS EVENING. THE HI-RES MODELS RUNS OF THE NMM/ARW WRF AND HRRR ARE
IN GOOD AGREEMENT WITH SOME LIGHT PRECIP OVER THE SOUTH THROUGH 09Z
FRIDAY AND INCREASED POPS TO LIKELIES THROUGH 06Z IN THIS AREA.
THE WRF SIMULATED GOES-R PRODUCTS ARE DEPICTING A CLEAR SLOT MOVING
INTO CENTRAL IOWA FROM WEST TO EAST LATE TONIGHT INTO THE OVERNIGHT
HOURS AND SOMEWHAT AGREE THERE SHOULD BE A BRIEF PERIOD OF CLEAR
SKIES B/T 03-09Z. HOWEVER...THE SIMULATED PRODUCTS DO NOT HAVE A
GOOD HANDLE ON CURRENT SATELLITE TRENDS WRT TO HIGHER CLOUDS IN
NORTHWEST IOWA. SO DID NOT GO COMPLETELY CLEAR IN THE NORTH WITH
ANOTHER WAVE MOVING INTO NORTHERN IOWA FRIDAY. LEANED TOWARD THE
COOLER NAM12 FOR LOWS TONIGHT IN NORTHERN IOWA AND THE NISH
VALLEY...THEN CLOSER TO THE GFS ACROSS THE SOUTHEAST.
.LONG TERM /FRIDAY THROUGH THURSDAY/...
MORE WRINKLES FOR THE WEEKEND EVENT...THOUGH SOME CONSENSUS
BEGINNING TO SHOW UP REGARDING PREFERRED SOLUTION AND FORECAST.
FIRST OF ALL THE SYSTEM ON FRIDAY APPEARS TO BE GRAZING THE FAR
NORTH WITH SOME LIGHT SNOW AS MORE OF THE FORCING IN THE PAST TWO
RUNS WILL OCCUR OVER SOUTHERN MINNESOTA...WITH JUST SOME LIGHT
PRECIPITATION REACHING THE FAR NORTHERN COUNTIES OF THE FORECAST
AREA AS THE SYSTEM PASSES TO THE EAST. THIS WILL LIMIT ANY SNOWFALL
ACCUMULATIONS TO AN INCH OR LESS WITH THE FIRST WAVE DROPPING EAST
SOUTHEAST WITH TIME TOMORROW. ONE OF THE WRINKLES IN THE UPCOMING
FORECAST HAS BEEN A SHIFT TO LESS COLD AIR ARRIVING IN THE NEXT 48
HOURS AHEAD OF THE LATE WEEKEND WAVES. THIS WILL MODERATE BOTH
HIGHS AND LOWS...RESULTING IN A SLIGHTLY LONGER CHANGEOVER FROM
LIQUID TO FROZEN PRECIPITATION ON SUNDAY. THIS IS MAINLY DUE TO THE
LACK OF UPPER LEVEL ENERGY PHASING WHICH KEEPS THE NORTHERN STREAM
SHORT WAVE STRONGER AND THE COLD AIR FROM DRIVING SOUTH BEHIND THE
SYSTEM FAST ENOUGH TO INTERACT WITH THE SOUTHERN STREAM. THUS...WITH
LITTLE COLD AIR ADVECTION IN THE OFFING UNTIL THE STORM PASSES TO
THE EAST SUNDAY EVENING...THERE WILL BE LITTLE AMPLIFICATION OF THE
ENTIRE SYSTEM AND LESSER AMOUNTS OF FORCING...QPF...AND SNOWFALL
PRODUCTION OVER THE FORECAST AREA. NEVER THE LESS...SOME
ACCUMULATION IS EXPECTED AS THE TIMING OVER THE NORTH FAVORS A
QUICKER CHANGEOVER COMPARED TO THE SOUTH. WITH CONTINUED UNCERTAINTY
IN BOTH TIMING AND AREAL COVERAGE OF PRECIPITATION OVER THE RANGE OF
MODEL SOLUTIONS... HAVE OPTED TO LEAN TOWARD A MANUAL BLEND OF THE
EURO/NAM/GEM WITH LESS EMPHASIS ON THE GFS WHICH HAS DONE A COMPLETE
REVERSAL SINCE YESTERDAY. THE ONLY TREND IN THE MODELS NOW IS LITTLE
TO NO PHASING OF THE NORTHERN AND SOUTHERN STREAMS AND SLIGHTLY
WARMER TEMPS AS PREVIOUSLY MENTIONED. THUS...SOME LIGHT SNOW WITH A
POTENTIAL FOR A BRIEF PERIOD OF HEAVIER RAIN OR SNOW SATURDAY NIGHT
LATE NORTHEAST IS EXPECTED AS THE SYSTEM ROLLS ON THROUGH. SUNDAY
FOR THE MOST PART WILL EXPERIENCE FALLING TEMPERATURES WITH LESS
INTENSE PRECIPITATION. LIGHT ACCUMULATIONS OF SNOW WILL OCCUR BOTH
SATURDAY NIGHT AND SUNDAY OVER THE FORECAST AREA AND AMOUNTS WILL
RANGE FROM NEAR ONE HALF INCH IN THE SOUTH TO NEARLY 1.5 TO 2 INCHES
IN THE NORTHEAST. THOUGH THE COLD AIR FINALLY ARRIVES BY SUNDAY
NIGHT AND MONDAY...SOME MODERATION IS ALREADY EXPECTED TO OCCUR BY
TUESDAY THROUGH THURSDAY WHEN HIGHS REACH THE 30S TO LOWER 40S OVER
THE REGION SO WHAT SNOW DOES FALL THIS WEEKEND WILL SLOWLY DISAPPEAR
TOWARD NEXT THURSDAY. LITTLE TO NO PRECIPITATION WILL OCCUR AFTER
THE STORM SUNDAY...SO THE BALANCE OF THE EXTENDED FORECAST LOOKS
DRY.
&&
.AVIATION...07/00Z
-RA WILL CONTINUE TO AFFECT SOUTHERN SITES KDSM AND KOTM AS BOUNDARY
PUSHES SOUTH. CONDITIONS WILL REMAIN VFR AT SITES...WITH LOW
CEILINGS PUSHING THROUGH. WINDS WILL SHIFT TO THE NORTH BEHIND
BOUNDARY AND BE LIGHT. A SECONDARY SYSTEM WILL PUSH ACROSS THE NORTH
FOR LATE IN THE PERIOD...WITH CHANCES FOR LOW VFR CEILINGS AND
POSSIBLY PRECIPITATION...BUT NOT ENOUGH CONFIDENCE IN EASTWARD
EXTENT TO INCLUDE MENTION ATTM.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS JACKSON KY
1247 AM EST WED DEC 5 2012
.UPDATE...
ISSUED AT 1247 AM EST WED DEC 5 2012
UPDATED THE FORECAST TO BETTER TIME THE SYSTEM THROUGH THE AREA. WHEN
THE FRONT MOVES THROUGH...THERE HAS BE ABOUT A 2 HOUR PERIOD OF WIND
GUSTS GREATER THAN 20 MPH. THE FRONT SHOULD CONTINUE MOVING TO THE SE
AND WILL BE MOVE INTO VA AND TN BETWEEN BY 1:30 AM. THERE
PRECIPITATION EXTENDS ABOUT 80 MILES NORTHWEST OF THE FRONT...SO RAIN
SHOULD CONTINUE A FEW HOURS AFTER THE FRONT HAS PASSED. HAVE A LITTLE
CONCERN THAT THE CLOUDS MAY HANG IN LONGER DUE TO THE FLOW BECOMING
MORE NORTHEASTERLY BEHIND THE FRONT.
UPDATE ISSUED AT 1050 PM EST TUE DEC 4 2012
RAIN HAS FILLED BACK IN ALONG THE FRONT AND WILL ONLY NEED TO FINE
TUNE THE TIMING OF THE BACK EDGE TO THE PRECIP IN OUR HOURLY GRIDDED
DATABASE AS MAJORITY OF THE FORECAST IS ON TRACK TONIGHT. IT DOES
APPEAR BASED ON RADAR TRENDS THAT THE FRONT IS HANGING UP A BIT MORE
THAN EARLIER THOUGHT SO WILL PROLONG A SLIGHT CHANCE OF SHOWERS INTO
TOMORROW MORNING FOR OUR VA AND TN BORDER COUNTIES. OTHERWISE...NO
SUBSTANTIVE CHANGES ARE NEEDED. HAVE A GOOD NIGHT...
UPDATE ISSUED AT 823 PM EST TUE DEC 4 2012
THE COLD FRONT HAS NOW PASSED INTO OUR NORTHWEST COUNTIES HOWEVER
THE SOLID MASS OF RAINFALL THAT WAS ACCOMPANYING THE FRONT EARLIER
HAS WITHERED SUBSTANTIALLY AS IT HAS ENTERED EAST KENTUCKY. THERE IS
STILL ENOUGH PRECIP RIGHT ALONG THE FRONT TO JUSTIFY 100 POPS BUT
FORECAST QPF HAS BEEN REDUCED TO A QUARTER INCH OR LESS FOR MOST
LOCATIONS. TEMPS WILL REMAIN IN THE 60S UNTIL THE FRONT PASSES AND
THEN DROP QUICKLY THROUGH THE 50S. OUR HOURLY TEMP DATA WAS MASSAGED
USING THE RUC13 TIMING BUT THIS WILL NOT ALTER OUR MIN TEMP FORECAST
FOR NOW.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 255 PM EST TUE DEC 4 2012
SURFACE COLD FRONT IS CURRENTLY ALIGNED FROM NORTHWEST OHIO DOWN
THROUGH WESTERN KENTUCKY AND TENNESSEE. THE MAIN BAND OF
PRECIPITATION ASSOCIATED WITH THIS BOUNDARY IS STILL A FEW HOURS
AWAY...WITH MOST OF THIS ACTIVITY WORKING THROUGH IN THE 7 PM TO 12AM
TIME FRAME...AND THEN LINGERING A BIT LONGER IN THE SOUTHEAST AS THE
BOUNDARY SLOWS DOWN ALONG THE TERRAIN. EVERYONE WILL MEASURE OUT OF
THIS...SO SEE NO REASON TO NOT MAINTAIN NEAR 100 POPS. THERE HAS BEEN
SOME LIGHTNING ACTIVITY EMBEDDED WITHIN THE LINE...HOWEVER EXPECT
THESE TO WEAKEN AS IT COMES THROUGH EASTERN KENTUCKY...SO WILL LEAVE
OUT THE MENTION.
HIGH PRESSURE TRAVERSING THE GREAT LAKES AND OHIO VALLEY WILL THEN
PROVIDE DRY WEATHER ACROSS THE AREA FOR WEDNESDAY AND WEDNESDAY
NIGHT. TEMPERATURES WILL BE COOLER THAN WE HAVE BEEN SEEING
LATELY...BUT WILL STILL AVERAGE ABOVE NORMAL...WITH HIGHS GENERALLY
IN THE MID TO UPPER 50S...WITH A FEW LOWER 60S SOUTH ON WEDNESDAY.
LOWS WEDNESDAY NIGHT WILL DROP DOWN TO BELOW 30 IN SOME OF THE MORE
SHELTERED VALLEYS ALONG AND NORTH OF THE MOUNTAIN PARKWAY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 255 PM EST TUE DEC 4 2012
MODEL PATTERN BEGINS ON THU MORNING WITH A WEAK 50H RIDGE OVER THE
NRN APPALACHIAN MTS AND NEARLY ZONAL FLOW FROM THE PLAINS TO THE
OHIO VALLEY. A WEAK AREA OF LOW PRESSURE OVER THE ERN GULF IS THE
IMPETUS FOR A FEW RETURN FLOW SHOWERS IN THE TENN VALLEY AROUND THE
BACK SIDE OF THE SFC HIGH OVER ERN PA/NY. WEATHER SHOULD REMAIN DRY
AND WARM ALTHOUGH A FEW SPRINKLES COULD BE FOUND LATE THU. BY FRI...
AN AREA OF LOW PRESSURE...ACCOMPANIED BY A LEE SIDE TROUGH...WILL
FORM IN THE SRN PLAINS. THE SFC HIGH WILL HAVE MOVED TO THE ATLANTIC
AND A WARM FRONT WILL BEGIN FORMING FROM OK TO PA. LIFT OVER THE
WARM FRONT FROM THE PREVAILING SOUTHERLY WIND WILL CAUSE A BETTER
CHANCE OF PCPN TO FORM OVER THE OHIO RIVER WITH A GOOD CHANCE OF
RAIN OVER OUR NRN COUNTIES. WAVES ALONG THE FRONTAL BOUNDARY WILL
ENHANCE THE CHANCE FOR PCPN THRU THE REMINDER OF THE EXTENDED FCST.
TIMING OF EACH WAVE WILL BE THE DETERMINING FACTOR FOR TIMING OF
PCPN AND THERE IS LITTLE CONFIDENCE WITH THE FAST FLOW FOR PLACEMENT
OF PCPN IN THIS FCST. HAVE WORKED WITH THE 00Z ECMWF TO TRY TO TIME
PCPN INTO THE REGION AS THE ECMWF HAS BEEN FAIRLY CONSISTENT WITH
RUN TO RUN DETAILS. NEXT MAJOR FRONTAL PASSAGE WILL OCCUR TUE BUT
TIMING IS IN QUESTION EVEN HERE WITH THE ECMWF ABOUT 6 HOURS FASTER
THAN THE GFS AND MUCH CLEANER WITH THE PASSAGE AS THE PARENT LOW IS
FARTHER NORTH AND WEST OF THE GFS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1247 AM EST WED DEC 5 2012
THE FRONT SHOULD CONTINUE MOVING TO THE SE AND WILL BE MOVE INTO VA
AND TN BETWEEN BY 1:30 AM. THERE PRECIPITATION EXTENDS ABOUT 80
MILES NORTHWEST OF THE FRONT...SO RAIN SHOULD CONTINUE A FEW HOURS
AFTER THE FRONT HAS PASSED. HAVE A LITTLE CONCERN THAT THE CLOUDS
MAY HANG IN LONGER DUE TO THE FLOW BECOMING MORE NORTHEASTERLY
BEHIND THE FRONT. SKIES WILL CLEAR QUICKLY BY OR SHORTLY AFTER DAWN
AT THE TAF SITES WITH A LIGHT NORTHEAST WIND FORECAST THROUGH THE DAY
ON WEDNESDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJ
SHORT TERM...GEOGERIAN
LONG TERM....DUSTY
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS CARIBOU ME
258 PM EST WED DEC 5 2012
.SYNOPSIS...
A SECOND COLD FRONT WILL CROSS THE REGION THIS EVENING. HIGH
PRESSURE WILL BUILD ACROSS THE REGION ON THURSDAY AND THEN MOVE
EAST FRIDAY. LOW PRESSURE WILL APPROACH THE AREA SOUTHWEST ON SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
CHALLENGE WILL BE SNOW SHOWERS AND TEMPERATURES.
2ND COLD FRONT IS MOVING ACROSS THE NORTHERN 1/2 OF THE CWA ATTM
AND IS EXPECTED TO BE ACROSS DOWNEAST AND THE COAST LATER THIS
EVENING AND EARLY EVENING. SNOW SHOWERS MOVED ACROSS NORTHERN AND
WESTERN AREAS THIS AFTERNOON W/GUSTS UP TO 35 MPH AT KFVE. STRONG
LAPSE RATES AND CAA WILL LEAD TO GUSTY WINDS RIGHT INTO THE EVENING.
THE ASSOCIATED UPPER TROF IS SHOWN BY THE RUC AND CANADIAN
GEM(HANDLING THIS SET THE BEST) TO MOVE THROUGH THE REGION EARLY
TONIGHT. SOUNDINGS INDICATED LLVL RH IN PLACE AND SOME WEAK LIFT
TO CONTINUE W/ON AND OFF SNOW SHOWERS THROUGH 06Z. DECIDED TO KEEP
30% IN THERE UP THROUGH THIS TIME AND THEN THINGS DRY OUT
W/CLEARING EXPECTED. WINDS WILL STAY UP OVERNIGHT 10-20 MPH. THIS
WILL KEEP THE ATMOSPHERE MIXED KEEPING TEMPERATURES FROM DROPPING
OFF TOO FAR. MIDNIGHT CREW`S MINS LOOKED OK W/AN ADJUSTMENT UPWARD
TO ACCOUNT FOR THE WINDS. THIS MEANS UPPER TEENS NORTH TO AROUND
20 CENTRAL AREAS WHILE DOWNEAST AND THE COAST WILL SEE LOW/MID 20S.
THURSDAY WILL BE A SUNNY DAY BUT AT LEAST 15 DEGREES COLDER THAN
TODAY AS HIGH PRES BUILDS E AND COLD AIR IS IN PLACE. ONCE AGAIN,
MIDNIGHT CREW`S TEMPERATURES LOOKED FINE AND STAYED THE COURSE
W/UPPER 20S TO LOWER 30S NORTH WHILE MID 30S LOOK LIKE A GOOD FIT
FOR CENTRAL AND DOWNEAST. MUCH COLDER THURSDAY NIGHT AS HIGH PRES
SLIDES E AND OUR REGION GETS UNDER THE START OF WAA. THE
NUMERICAL MODELS TEND TO WARM THE LLVLS UP TO FAST W/THIS SETUP
AND STRONG INVERSION SETTING UP. ALSO, THE GUIDANCE APPEARS TO BE
TOO QUICK IN BRING HIGHER CLOUDS IN TOO FAST. THEREFORE, UNDERCUT
MINS THURSDAY NIGHT FROM WHAT THE MIDNIGHT CREW HAD BY SOME 3-5
DEGREES. THIS MEANS LOW/MID TEENS NORTH W/AROUND 20 FOR CENTRAL
AND DOWNEAST AREAS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
HIGH PRESSURE MOVES EAST OF THE AREA ON FRIDAY WITH WARMER
SOUTHWEST FLOW AND PARTLY CLOUDY SKIES. MOISTURE INCREASES FRIDAY
NIGHT AND INTO SATURDAY AHEAD OF OUR NEXT SYSTEM, WITH CONTINUED
WARM AIR ADVECTION ALOFT. HOWEVER, MODELS HAVE BEEN IN VERY POOR
AGREEMENT ON THE DETAILS OF THIS SYSTEM. EITHER WAY, THOUGH,
PRECIP AMOUNTS LOOK FAIRLY LIGHT WITH THE SYSTEM FRIDAY NIGHT
THROUGH SATURDAY NIGHT. MENTIONED FREEZING RAIN FOR LATE FRIDAY
NIGHT INTO SATURDAY MORNING DUE TO WARM AIR ALOFT BUT LIGHT WINDS
AND POOR MIXING NEAR THE SURFACE. PRECIP AMOUNTS WILL BE FAIRLY
LIGHT THOUGH.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
SYSTEM KICKS EAST OF THE AREA LATE SATURDAY NIGHT WITH A DRY AND
SEASONABLY COOL DAY FOR SUNDAY. HIGH PRESSURE BUILDS OVERHEAD FOR
LATE SUNDAY, BUT QUICKLY MOVES EAST. PRECIP CHANCES RETURN LATE
SUNDAY NIGHT AND CONTINUE THROUGH EARLY TUESDAY. HOWEVER, MODELS
ARE STILL HAVING TROUBLE WITH THIS SYSTEM. MODEL TREND, HOWEVER,
HAS BEEN FOR A WARMER SYSTEM WITH A POTENT SURFACE LOW TRACKING
FROM SOUTHWEST TO NORTHEAST FROM THE GREAT LAKES TO THE SAINT
LAWRENCE. THIS WOULD PUT US ON THE WARM SIDE OF THE STORM WITH
FREEZING RAIN CHANGING TO RAIN AND THEN BACK TO SNOW AT THE VERY
END.
DRY WEATHER FOR WEDNESDAY WITH COOL TEMPERATURES, BUT READINGS
RISING AS WE HEAD INTO THURSDAY AND FRIDAY.
&&
.AVIATION /19Z WEDNESDAY THROUGH SATURDAY/...
NEAR TERM: MAINLY VFR THROUGH THROUGH THURSDAY NIGHT W/A BRIEF
PERIOD OF MVFR THIS EVENING FOR SNOW SHOWERS. LLWS WILL BE A
CONCERN THROUGH 06Z AS THE COLD FRONT PASSES THROUGH.
SHORT TERM:
VFR FOR FRIDAY, BUT CONDITIONS WILL DETERIORATE TO MVFR AND
POSSIBLY IFR LATE FRIDAY NIGHT AS ONSHORE FLOW DEVELOPS. MVFR AND
IFR EXPECTED FOR SATURDAY WITH LIGHT PRECIPITATION AND LOW
CEILINGS.
&&
.MARINE...
NEAR TERM: KEPT THE SCA UP THROUGH 12Z THURSDAY. WINDS HAVE
DROPPED BELOW 20S KTS W/WAVE HEIGHTS 6-7 FT(COMBINED SEA/SWELL
STATE). EXPECTING WINDS TO COME BACK UP TONIGHT AS THE FRONT AND
CAA HIT THE WATERS. STAYED W/GUSTS TO 30 KTS THIS EVENING AND THEN
BROUGHT WINDS DOWN AFT 12Z AS HIGH PRES PUSHES QUICKLY E. THE SEAS
WILL BE SLOWER TO RESPOND INITIALLY HOLDING UP TO 3-5 FT AND THEN
FALLING BACK BY EARLY THURSDAY AFTERNOON INTO THURSDAY NIGHT.
SHORT TERM:
WINDS AND SEAS EXPECTED TO INCREASE TO SMALL CRAFT LEVELS FRIDAY
BUT DIMINISH TO JUST UNDER SMALL CRAFT LEVELS ON SATURDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR ANZ050>052.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...FOISY
LONG TERM...JORDAN
AVIATION...HEWITT/FOISY
MARINE...HEWITT/FOISY
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
332 AM EST WED DEC 5 2012
.SYNOPSIS...
ISSUED AT 332 AM EST WED DEC 5 2012
HIGH PRESSURE OVER MICHIGAN WILL MEAN PARTLY CLOUDY SKIES TODAY.
HIGH TEMPERATURES IN THE MID TO UPPER 30S WILL SLOWLY RISE TO THE
LOWER 40S THURSDAY AS THE HIGH SLIPS EAST AND WARMER AIR RETURNS TO
THE AREA. MIXED RAIN AND SNOW ARE POSSIBLE OVER THE WEEKEND AS A
STORM SYSTEM MOVES NORTHEAST TOWARD THE GREAT LAKES.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 332 AM EST WED DEC 5 2012
FORECAST CONCERNS DEAL WITH PCPN TRENDS THURSDAY NIGHT AND FRIDAY.
THE CORE OF THE COLD AIR MOVING OVER LOWER MICHIGAN AND CAUSING SOME
STRATOCU WILL DRIFT EAST TODAY LEADING TO PT CLDY SKIES. THE NEXT
WEATHER SYSTEM WILL BE THE APPROACH OF BOTH A COLD FRONT AND A WAVE
OF LOW PRESSURE THURSDAY NIGHT. ISENTROPIC LIFT NEAR THE FRONTAL
BOUNDARY LEADS TO LOW CONDENSATION PRESSURE DEFICITS AND RAIN
THURSDAY NIGHT ACROSS THE CWA. APPROACHING LOW PRESSURE FROM THE SRN
PLAINS WILL ALSO DRAW SOME MOISTURE NWD. AS THE WAVES MOVES BY
FRIDAY...SOME COLDER AIR WILL WORK INTO THE SYSTEM RESULTING IN
MIXED RAIN AND SNOW OVER THE NRN CWA.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 332 AM EST WED DEC 5 2012
WE WILL MAINTAIN LOW POPS FOR SOME MIXED LIGHT RAIN AND LIGHT SNOW
SHOWERS FRIDAY NIGHT THROUGH SATURDAY. THIS WITH A NEARLY STATIONARY
BOUNDARY DRAPED ACROSS THE LWR OH VALLEY REGION AND SOME LIGHT
OVERRUNNING PCPN EXPECTED WELL TO THE NORTH OF THAT BOUNDARY INTO
SOUTHERN LWR MI.
THE FCST FOR LATE IN THE WEEKEND INTO EARLY NEXT WEEK IS COMPLICATED
DUE TO MEDIUM RANGE GUIDANCE DISCREPANCIES AND LACK OF RUN TO RUN
CONSISTENCY. WE WILL LEAN TOWARD THE 00Z ECMWF WHICH SUGGESTS THAT
THE BOUNDARY WILL LIFT NORTHWARD WITH A LOW PRESSURE WAVE SUNDAY
CAUSING PCPN TO CHANGE TO MAINLY PLAIN RAIN SHOWERS.
THE UPPER LEVEL PATTERN WILL BECOME MORE AMPLIFIED SUNDAY INTO EARLY
NEXT WEEK AS AN UPPER LEVEL TROUGH DEEPENS OVER THE PLAINS STATES
AND SHIFTS EAST INTO OUR REGION TOWARD TUESDAY. THIS PATTERN COULD
BE CONDUCIVE TO CYCLOGENESIS OVER THE ARKLATEX REGION SATURDAY
NIGHT/SUNDAY AND THAT LOW PRESSURE SYSTEM WILL TRACK NORTHEASTWARD.
00Z GFS GUIDANCE SUGGESTS THIS SYSTEM COULD BRING SOME ACCUMULATING
SNOW INTO PORTIONS OF LWR MI AS EARLY AS LATE SUNDAY AND MAINLY FOR
MONDAY AND TUESDAY. HOWEVER IT IS NOTED THAT THE 00Z ECMWF ONLY
SHOWS A FAIRLY WEAK LOW TRACKING NE THRU OUR REGION SUNDAY NIGHT
(MUCH FASTER THAN THE 12Z EC) AND DOES NOT SHOW NEARLY AS MUCH
POTENTIAL FOR ACCUMULATING SNOW EARLY NEXT WEEK.
TEMPS WILL AVERAGE A LITTLE ABOVE NORMAL FRIDAY NIGHT THROUGH SUNDAY
BEFORE RETURNING TO NEAR TO EVEN POTENTIALLY A LITTLE BELOW NORMAL
FOR EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1144 PM EST TUE DEC 4 2012
LITTLE CHANGE IN THINKING FROM THE PREVIOUS FORECAST. THE AREA OF
LOW CLOUDS IS TRYING TO MOVE SOUTH BUT SEEMS TO BE STRUGGLING TO
GET SOUTH OF ROUTE 10...WHICH IS WHAT THE NAM12 IS SUGGESTING
WOULD HAPPEN (THROUGH 06Z). THE RAP MODEL BRING THE LOW CLOUDS
FARTHER SOUTH BUT STILL ONLY BRINGS THEM TO I-96 FOR THE MOST
PART. SO I DID NOT CHANGE MY OVERALL TAF SITE FORECAST... BRINGING
MVFR CIGS MKG...GRR AND LAN AND KEEPING AZO...BTL AND JXN CLEAR
THROUGH WEDNESDAY.
&&
.MARINE...
ISSUED AT 332 AM EST WED DEC 5 2012
THE SCA REMAINS IN EFFECT THROUGH THIS AFTERNOON. WAVES WILL
GRADUALLY DECREASE THROUGHOUT THE DAY. HOWEVER...A SCA MAY BE NEEDED
AGAIN TONIGHT AS WINDS INCREASE AHEAD OF THE NEXT COLD FRONT.
&&
.HYDROLOGY...
ISSUED AT 332 AM EST WED DEC 5 2012
NO HYDRO ISSUES EXPECTED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
LMZ844>849.
&&
$$
SYNOPSIS...93
SHORT TERM...93
LONG TERM...LAURENS
AVIATION...WDM
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1144 PM EST TUE DEC 4 2012
.SYNOPSIS...
ISSUED AT 335 PM EST TUE DEC 4 2012
COLD AIR WILL SETTLE OVER THE REGION TONIGHT BEHIND A COLD FRONT
EXITING TO THE SOUTHEAST. OVERNIGHT LOWS WILL FALL INTO THE 20S...
WHICH IS ABOUT 20 DEGREES COLDER THAN LAST NIGHTS LOWS. HIGH
PRESSURE WILL PROVIDE DRY WEATHER FOR WEDNESDAY AND THURSDAY BEFORE
ANOTHER CHANCE OF LIGHT RAIN OR MIXED LIGHT RAIN AND SNOW RETURNS
FOR THE END OF WEEK.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 335 PM EST TUE DEC 4 2012
CLEARING CONTINUES TO ADVANCE EAST THIS AFTERNOON AND MUCH DRIER AIR
WITH DEW POINTS IN THE 20S/TEENS IS NOTED UPSTREAM. THIS SETS THE
STAGE FOR A COLD NIGHT...BUT THE NW FLOW COLD ADVECTION MAY ALSO
GENERATE SOME LAKE EFFECT STRATUS LATER TONIGHT WHEN H8 TEMPS AROUND
-10C ARRIVE FROM THE NORTH.
THE CHANCE FOR SNOW SHOWERS WITH THESE CLOUDS IS QUITE LOW DUE TO
VERY SHALLOW MOISTURE DEPTH... BUT WILL CARRY A FEW FLURRIES IN THE
FAR NRN CWFA. THE BUFKIT PROFILE AT CADILLAC DOES SHOW ICE
NUCLEATION
AT THE TOP OF THE CLOUDS AFTER MIDNIGHT... BUT ELSEWHERE IN THE CWFA
THERE IS NO NUCLEATION PRESENT. ITS ALSO QUESTIONABLE IF THE CLOUDS
WILL MAKE IT MUCH FARTHER SOUTH THAN ABOUT I-96.
WHATEVER LAKE CLOUDS/FLURRIES ARE PRESENT ON WEDNESDAY MORNING
SHOULD DIMINISH IN THE AFTERNOON AS THE SFC HIGH BUILDS IN AND THE
LOW LEVEL WINDS BECOME NORTHEASTERLY/ANTICYCLONIC.
ISENTROPIC LIFT DEVELOPS ON THURSDAY NIGHT WHICH MAY RESULT IN SOME
LIGHT RAIN BREAKING OUT AS CONDENSATION PRESSURE DEFICITS GRADUALLY
LOWER.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 335 PM EST TUE DEC 4 2012
UPPER PATTERN IS FORECAST TO TRANSITION FROM A ZONAL FLOW TO AN
UPPER TROUGH AS WE MOVE THROUGH THE PERIOD. THE DETAILS OF THE
EVOLUTION THOUGH REMAIN DIFFICULT TO DISCERN AS THERE ARE
DISCREPANCIES BETWEEN THE ECWMF AND THE GFS. BY EARLY NEXT WEEK
TROUGHING IS FORECAST TO STRETCH THROUGH THE PLAINS STATES WITH
LOWER MICHIGAN ON THE DOWNSTREAM SIDE OF THE TROUGH IN A LOCATION
WHERE SYSTEM EJECTING FROM THE LONGWAVE TROUGH WILL MOVE THROUGH.
THE TIMING AND TRAJECTORY OF THESE SYSTEMS ARE WHERE FORECAST
PROBLEMS DEVELOP.
IN GENERAL TRIED TO TREND THE FORECAST TOWARD THE ECMWF GIVEN ITS
BETTER PERFORMANCE IN THE LONG RANGE. OVERALL THOUGH DID NOT MAKE
SIGNIFICANT CHANGES GIVEN MODEL DISPARITY.
FRIDAY INTO SATURDAY THE GFS LIFTS A LOW ALONG A BOUNDARY THROUGH
THE GREAT LAKES REGION...WHILE THE ECMWF DOES NOT GENERATE A LOW
KEEPING A BOUNDARY IN THE OHIO VALLEY. HAVE CHANCE POPS FOR RAIN AND
SNOW GIVEN THE FACT THAT WE WILL BE NEAR THE TRANSITION ZONE.
SUNDAY INTO SUNDAY NIGHT THE ECMWF LIFTS A LOW THROUGH THE AREA WITH
A WEAKER PATTERN NOTED IN THE GFS. AGAIN...FORECAST CONFIDENCE IS
LOW GIVEN THE LACK OF CONSISTENCY AMONGST THE OPERATIONAL MODELS.
A STRONGER DEEPER LOW IS FORECAST TO LIFT OUT OF THE LONGWAVE TROUGH
AND PUSH OUR DIRECTION MONDAY NIGHT INTO TUESDAY. THE ECMWF IS
FURTHER NORTH WITH THE TRACK AND WOULD PUT DOWN SOME SNOW ACROSS OUR
FORECAST AREA. AT FURTHER RANGES LIKE NEXT TUESDAY THOUGH CONFIDENCE
IS LOW.
OVERALL PERIODS OF RAIN/SNOW THROUGH THE LONG TERM WITH TEMPERATURES
NEAR TO SLIGHTLY ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1144 PM EST TUE DEC 4 2012
LITTLE CHANGE IN THINKING FROM THE PREVIOUS FORECAST. THE AREA OF
LOW CLOUDS IS TRYING TO MOVE SOUTH BUT SEEMS TO BE STRUGGLING TO
GET SOUTH OF ROUTE 10...WHICH IS WHAT THE NAM12 IS SUGGESTING
WOULD HAPPEN (THROUGH 06Z). THE RAP MODEL BRING THE LOW CLOUDS
FARTHER SOUTH BUT STILL ONLY BRINGS THEM TO I-96 FOR THE MOST
PART. SO I DID NOT CHANGE MY OVERALL TAF SITE FORECAST... BRINGING
MVFR CIGS MKG...GRR AND LAN AND KEEPING AZO...BTL AND JXN CLEAR
THROUGH WEDNESDAY.
&&
.MARINE...
ISSUED AT 335 PM EST TUE DEC 4 2012
SMALL CRAFT ADVISORIES ARE IN EFFECT THROUGH WEDNESDAY FOR NORTHWEST
FLOW COLD ADVECTION BEHIND THE EXITING COLD FRONT. THE SFC HIGH WILL
BRING DECREASING WINDS/WAVES LATE WEDNESDAY INTO WEDNESDAY NIGHT.
&&
.HYDROLOGY...
ISSUED AT 335 PM EST TUE DEC 4 2012
TWO NARROW SWATHS OF HEAVIER RAIN WITH AMOUNTS NEAR ONE INCH FELL
LAST NIGHT. ONE WAS FROM PENTWATER TO TUSTIN AND ANOTHER ONE WAS
FROM THREE RIVERS TO MARSHALL. ELSEWHERE RAIN AMOUNTS WERE MOSTLY
UNDER 0.25 INCH. NO HYDRO PROBLEMS NOTED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST WEDNESDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...DUKE
AVIATION...WDM
HYDROLOGY...MEADE
MARINE...MEADE
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
924 PM CST THU DEC 6 2012
.DISCUSSION...
Now appears after the fact that the 18z model runs were out to lunch
as far as the rain is concerned for tonight. 00z TOP raob was pretty
dry below 700mb except for the small layer of moisture around 850mb.
00z NAM and RAP are much much drier and barely eke out any qpf
overnight. Best chance for light rain this evening will be across
far northern MO and even then that area doesn`t look to promising.
After midnight some light rain or sprinkles may try to form over
parts of west central and central MO as the moisture thickens around
850mb. Latest satellite data shows a weak mid level shortwave now in
far eastern KS and as it passes by it strips away the deeper
moisture and thus ends the threat of rain. Appears the upper jet
dynamics associated with the southern stream don`t trump the lack of
decent moisture.
Bottom-line is need to lower pops and even where slight chance pops
remain it may be more of a case of a few sprinkles. Otherwise, no
major changes made to any of the other elements.
MJ
&&
.PREV DISCUSSION...
Short Term (Tonight and Friday)...
In the near term, the primary forecast concern will be precipitation
chances for tonight through midday Friday. Pacific midlevel moisture
streaming through the Plains states has combined with a small amount
of energy ejecting out of the semi-permanent lee-side trough feature
over the southern High Plains to create light showers across
portions of eastern Nebraska, eastern Kansas, western Missouri, and
Iowa this afternoon. However, dry near-surface conditions has led to
a large amount of evaporation below cloud base, keeping the amount of
rain that reaches the surface nominal. Forcing for precipitation from
the southern shortwave trough looks strongest across the majority of
the forecast area in the 03z-09z time frame, while relative low-level
moisture also increases, slightly increasing the chance for any
measurable precipitation. The overall chance of showers remains low
through the period, but occurs over an extended period of time from
this afternoon through Friday afternoon as the southern jet slowly
drops southeast. Rain chances associated with this system should end
altogether sometime late Friday afternoon or evening.
Fairly extensive cloud cover should keep high temperatures muted
throughout the period (albeit above normal), and low temperatures
mild. The only exception will be over the northwest on Friday night,
as clouds gradually clear and temperatures begin to drop.
Laflin
Long Term (Saturday-Thursday)...
Consistency among forecast model guidance has increased over the
last couple of runs with forecast confidence also increasing with
regards to weekend precipitation chances. Forecast confidence
remains high for significant cooler weather Sunday into early next
week before temperatures begin to moderate the middle of next week.
Strong shortwave energy moving through the Pacific Northwest into
the Central Rockies will deepen a broad upper trough in the Plains
and the Ohio Valley. In response to height falls aloft, surface low
pressure is progged to develop across the Northern Plains and track
through the upper Midwest with the potential of another surface low
to move through the Southern Plains into the Lower and Middle
Mississippi Valley. An associated strong cold front will move
through the Plains entering Northwest Missouri early Sunday morning.
Strong cold air advection behind the front will likely produce
falling temperatures Sunday afternoon.
Precipitation amounts are expected to remain light. Initially
precipitation will be driven by warm air advection and moisture
transport processes ahead of the frontogenetic forcing. Due to the
progressive movement of the upper trough...only shallow moisture
return is anticipated in Northeast Kansas and Northwest Missouri
with deeper moisture return occurring across the Lower and Middle
Mississippi River Valley. Thus have continued with precipitation
amounts generally less than a quarter of an inch. While light snow
will be possible post frontal passage, drier air will rapidly advect
into the dendritic zone. This drier air intrusion along with low
snowfall rates and warm ground temperatures from the recent above
normal temperatures will limit any accumulation to around a half
inch or less where snow occurs.
Below normal temperatures are likely Monday and Tuesday before
temperatures begin to rebound with high pressure building east and
southerly return flow developing with a lee side trough in the High
Plains.
Angle
&&
.AVIATION...
For the 00z TAFs, favorable upper jet dynamics aloft and a
moistening of the airmass below the mid cloud deck has resulted in
MVFR cigs across eastern KS and west central MO. Latest NAM/GFS Bufr
soundings even more negative and lower cigs to below 1500ft
overnight. Will need to see more rain develop than what we currently
see to get cigs that low. So far models have been overly generous on
qpf. So, will go with MVFR cigs overnight but increase the risk of
rain occurring at KMCI/KMKC. Rain chances should end by sunrise as
upper level impulse moves east and southern stream jet segment
shifts south and east.
Lack of drying behind the inverted surface trough currently sagging
south through the terminals suggest MVFR cigs will hang around
through the day on Friday.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
331 AM MST WED DEC 5 2012
.SHORT TERM...VALID FOR TDY AND THU...
THE ENERGETIC SHORT WAVE TROUGH OBSERVED OVER BRITISH COLUMBIA AT
10 UTC WILL HELP DRIVE A PATTERN CHANGE THE NEXT FEW DAYS...WHICH
WILL BEGIN WITH A COLD FRONTAL PASSAGE THIS AFTERNOON.
TODAY...A LOW- AND MID-LEVEL THERMAL RIDGE WILL CROSS THE AREA IN
ADVANCE OF A SURFACE COLD FRONT...WITH 850-HPA TEMPERATURES OF 10
TO 12 C IN PLACE ACROSS THE AREA AROUND 18 UTC. ALL OF THE 00 UTC
GUIDANCE IS A BIT FASTER WITH THE FRONTAL PASSAGE...SUGGESTING IT
COULD BE ALL THE WAY THROUGH SOUTHEASTERN MT BY 00 UTC. HIGHS ARE
THUS A BIT DIFFICULT TO PIN DOWN TODAY...AND WITH THE UNCERTAINTY
IN FRONTAL TIMING AND POTENTIAL FOR ABUNDANT CLOUDS WE FELT USING
THE 00 UTC MULTI-MODEL CONSENSUS WAS THE BEST APPROACH FOR HIGHS.
MOISTURE CHANNEL IMAGERY AT 10 UTC SHOWS SUBTLE DRYING ALOFT OVER
NORTHERN CA...WHICH IS LIKELY ASSOCIATED WITH A NARROW 80+ KT JET
STREAK THAT MOST 00 UTC GUIDANCE PICKED UP ON. THE EXIT REGION OF
THAT JET CIRCULATION IS EXPECTED TO CROSS THE AREA DURING THE MID
TO LATE AFTERNOON...FAVORABLY TIMING ITS PASSAGE WITH THE FRONTAL
ZONE. THAT SHOULD CREATE AN ENVIRONMENT FAVORABLE FOR SOME SHOWER
ACTIVITY...MUCH LIKE THE 03 UTC SREF AND RECENT RAP RUNS SUGGEST.
CLIMATOLOGICALLY...DOWNSLOPE FLOW WILL USUALLY FAVOR SHOWERS EAST
OF BILLINGS...AND EVEN THE 03 UTC SREF PICKS UP ON THAT...SO POPS
ARE RELATIVELY HIGHER /IN THE 30 PERCENT RANGE/ FOR MILES CITY...
HYSHAM...AND BROADUS AFTER 18 UTC. NOTE THAT THE JET STREAK COULD
HELP ENHANCE SNOW OVER THE MOUNTAINS FOR A TIME TOO...AND MOST OF
THE 00 UTC GUIDANCE SUPPORTS ONE TO TWO INCHES NEAR COOKE CITY.
AS FOR WINDS...WE DECIDED TO LEAVE THE ADVISORY UP FOR LIVINGSTON
AND NYE WITH THE MORNING FORECAST SINCE OBSERVED SPEEDS AT 10 UTC
ARE NEAR CRITERIA. THERE IS OFTEN A BIT OF A BUMP UP IN GAP WINDS
NEAR AND JUST AFTER SUNRISE AND THAT IS POSSIBLE IN THIS CASE TOO
WITH THE INVERSION ABOVE THE VALLEY FLOORS IN PLACE UNTIL 15 UTC.
AFTER THAT TIME...THE STABLE LAYER ERODES AND THE GRADIENT SHOULD
BECOME UNFAVORABLE FOR GAP-INDUCED WINDS. MIXING WILL KEEP THINGS
GUSTY THOUGH...AND IN FACT THE ENTIRE AREA COULD HAVE A PERIOD OF
GUSTY WINDS BETWEEN ABOUT 21 AND 03 UTC AS A 4 HPA/3 HOUR SURFACE
PRESSURE RISE MAXIMUM FOLLOWS THE COLD FRONT.
TONIGHT...WEAK FRONTOGENESIS IS EXPECTED FROM ABOUT LIVINGSTON TO
SHERIDAN...SO SOME LOW POPS ARE ADVERTISED FOR THOSE AREAS. WINDS
ALOFT SHIFT A BIT WEST-NORTHWESTERLY...WHICH SHOULD HELP MOISTURE
DIMINISH IN THE MOUNTAINS.
THU AND THU NIGHT...OUR MAIN FOCUS IS ON THE POTENTIAL FOR A BAND
OF ACCUMULATING SNOW...MAINLY SOUTH OF A LINE FROM LIVINGSTON AND
BILLINGS TO BROADUS. THE LAST SEVERAL MODEL CYCLES HAVE AGREED ON
A BURST OF MID-LEVEL FRONTOGENESIS CENTERED AROUND 700 HPA ACROSS
THE AREA BETWEEN ABOUT 18 AND 06 UTC...WITH VERTICAL MOTION AIDED
BY THE EXIT REGION OF A 120 KT 300-HPA JET STREAK DIVING INTO WY.
THE 00 UTC GUIDANCE GENERALLY PUSHED THE FRONTOGENESIS JUST A BIT
FURTHER SOUTH...AND THUS HAS THE HIGHER QPF SOUTH OF BILLINGS. WE
KEPT LIKELY POPS IN THE FORECAST EVEN FOR BILLINGS THOUGH BECAUSE
TRENDS LIKE THIS CAN SOMETIMES BE MISLEADING WITH A FRONTOGENESIS
BAND. WET BULB ZERO HEIGHTS SUGGEST ALL OF THE PRECIPITATION WILL
BE IN THE FORM OF SNOW...EVEN WHEN SURFACE TEMPERATURES ARE ABOVE
32 F ON THU AFTERNOON...SO WE DID DECIDE TO FORGO ANY MIX OF RAIN
AND SNOW IN THE FORECAST. TAKEN AT FACE VALUE...THE 00 UTC MODELS
ACTUALLY SHOW WET BULB ZERO HEIGHTS JUST HIGH ENOUGH FOR A MIX IN
THE PARADISE VALLEY DURING THE DAY THU...BUT THE 03 UTC SREF ONLY
SHOWS SNOW WITH THE NCEP PRECIPITATION-TYPE ALGORITHM...WHICH WAS
ENOUGH FOR US TO KEEP THINGS AS ALL SNOW FOR NOW. ALTHOUGH QPF IS
NOT EXPECTED TO BE SIGNIFICANT...GFS FORECAST SOUNDINGS SIMULATED
MOST OF THE OMEGA WITHIN THE DENDRITIC GROWTH ZONE THU NIGHT. THE
SNOW-TO-LIQUID RATIOS DERIVED FROM 03 UTC SREF OUTPUT WERE AROUND
15 TO 1 ON THU NIGHT TOO...SO WE COULD EASILY PICK UP ONE TO FOUR
INCHES OF SNOW IN SOME AREAS. THIS COULD REQUIRE AN ADVISORY DOWN
THE ROAD...ONCE WE ARE CONFIDENT IN THE PLACEMENT OF THE FORCING.
HOWEVER...LOW-LEVEL UPSLOPE FLOW WILL BE LACKING...AND DEEP-LAYER
MOISTURE IS MODEST WITH PRECIPITABLE WATER VALUES OF 0.25 INCHES.
THUS...THIS EVENT IS FAR FROM A SLAM DUNK. SCHULTZ
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
MEDIUM RANGE GUIDANCE REMAINS IN FAIRLY GOOD AGREEMENT WITH A
SPEEDY NORTHWEST FLOW DOMINATING THE REGION. NUMEROUS DISTURBANCES
WILL RIDE THE FLOW ALL THE WAY THROUGH THE MIDDLE OF NEXT WEEK
AND BEYOND. WHILE THE PATTERN WILL BE ACTIVE AND CHALLENGING WITH
TIMING AND STRENGTH OF EACH SYSTEM...NO WIDESPREAD AND SIGNIFICANT
WEATHER IMPACTS ARE ANTICIPATED AT THIS TIME. ALTHOUGH...NORTHWEST
FLOW CAN BE TRICKY AND WILL HAVE TO BE MONITORED FOR POTENTIAL
STRENGTHENING OF ANY PARTICULAR WAVE AS WE PROGRESS THROUGH TIME.
ITS ADVISED TO STAY TUNED TO THE FORECAST.
FORCING WITH EACH WAVE SHOULD BE ENOUGH TO PRODUCE PERIODIC
EPISODES OF LIGHT SNOWFALL. WITH THE ADVERTISED STRENGTH AND SPEED
OF THESE DISTURBANCES...NO PARTICULAR SYSTEM RIGHT NOW LOOKS TO
BE ABLE TO PRODUCE MORE THAN A AN INCH OR TWO OF SNOW AT
BEST...MORE IN SOME FAVORED FOOTHILLS AND MOUNTAINS. IT LOOKS LIKE
IT WILL BE A WINDY PERIOD AS WELL WITH EACH PASSING SURFACE LOW
PRESSURE AND COLD FRONTS. THIS COULD BE AN ADDED IMPACT TO WATCH
FOR LOCAL BLOWING SNOW AT TIMES. THE FLOW WILL ALSO KEEP
TEMPERATURES IN CHECK THROUGH THE PERIOD...SLIGHTLY BELOW OUR
NORMALS.
FRIEDERS
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL OVER THE NEXT 24 HOUR PERIOD. A
COLD FRONT THAT WILL MOVE THROUGH THE AREA THIS AFTERNOON MAY
PRODUCE WIDELY SCATTERED RAIN AND SNOW SHOWERS INTO TONIGHT. THEY
ARE NEXT EXPECTED TO IMPACT CEILINGS OR VISIBILITIES EXCEPT FOR
OCCASIONAL MOUNTAIN OBSCURATIONS. GUSTY WINDS WILL CONTINUE TO
PLAGUE AREAS IN AND AROUND LIVINGSTON WITH GUSTS GREATER THAN 40
KTS POSSIBLE THROUGH MID DAY TODAY. FRIEDERS
&&
.PRELIMINARY POINT TEMP/POPS...
TDY THU FRI SAT SUN MON TUE
-------------------------------------------------------
BIL 058 028/036 024/034 026/029 011/024 019/032 021/037
2/W 14/S 63/S 24/S 31/B 13/S 11/B
LVM 053 026/034 019/034 026/026 008/023 015/031 015/033
2/W 26/S 63/S 44/S 32/S 34/S 31/E
HDN 059 029/037 025/035 020/029 009/023 015/030 017/035
3/W 22/S 63/S 24/S 31/B 13/S 11/B
MLS 055 025/037 021/032 019/029 011/021 015/029 019/033
3/W 22/S 43/S 24/S 31/B 13/S 11/B
4BQ 057 027/038 021/034 019/029 011/022 011/028 017/032
3/W 32/S 64/S 14/S 31/B 13/S 11/B
BHK 056 022/035 020/032 017/028 011/020 011/026 017/030
3/W 21/B 32/S 24/S 31/B 13/S 11/E
SHR 056 027/036 019/033 015/028 007/018 009/024 011/033
2/W 22/S 63/S 14/S 31/B 13/S 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY IN EFFECT UNTIL 6 PM MST THIS EVENING FOR ZONES
65-66.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1020 AM CST WED DEC 5 2012
.DISCUSSION...
WIND...TEMPERATURES AND LIGHT PRECIPITATION CONTINUE TO BE A
CHALLENGE TODAY. MODELS ARE IN GOOD AGREEMENT...BUT WILL LEAN ON
HIGH RESOLUTION RAP FOR FORECAST DETAILS.
15 UTC RAP SHOWS A NARROW CORRIDOR OF 40 TO 50 KTS AT 925 HPA
SLIDE ACROSS THE FORECAST AREA TODAY. MODEL SOUNDINGS SUGGEST A
VERY SHALLOW MIXED LAYER...UP TO 950 HPA AT 18 UTC AND BRIEFLY
REACHING 925 HPA BY 21 UTC. THE STRONGEST WINDS WILL BE ACROSS THE
NORTHERN VALLEY WITH NEARLY 40 KTS AT THE TOP OF THE MIXED LAYER
BY MID-AFTERNOON. WIND ADVISORY CRITERIA MAY BE REACHED BRIEFLY
ACROSS PORTIONS OF PEMBINA/KITTSON/WALSH/MARSHALL COUNTIES...BUT
CONFIDENCE NOT HIGH ENOUGH TO ISSUE AT THIS TIME. WILL MONITOR
OBSERVATIONS CLOSELY AND ISSUE HEADLINES THIS AFTERNOON IF
NECESSARY. EITHER WAY...IT WILL BE BREEZY TO LOCALLY WINDY
TODAY...ESPECIALLY ALONG THE VALLEY FLOOR.
TEMPERATURES ALREADY IN THE UPPER TEENS TO MID 20S AND WITH STRONG
LOW-LEVEL WARM AIR ADVECTION AND SOME FILTERED SUN THROUGH MID-
HIGH LEVEL CLOUD COVER...AFTERNOON HIGHS WILL APPROACH 30 DEGREES
ACROSS THE CANADIAN BORDER AND THE MID TO UPPER 30S ACROSS THE
SOUTHERN VALLEY.
TRIMMED 20 POPS LATE AFTERNOON AS IT APPEARS ANY LIGHT FREEZING
RAIN SHOULD HOLD OFF UNTIL AFTER 0O UTC. WILL FURTHER ADDRESS
FREEZING PRECIPITATION WITH AFTERNOON FORECAST PACKAGE.
&&
.AVIATION...
EXPECTING MAINLY VFR MID/HIGH CLOUD COVER TODAY WITH SOME LOWER VFR
CIGS MOVING INTO NW FA LATE AFTERNOON. WINDS WILL INCREASE OUT OF
THE SE AND WILL BE BREEZY TO WINDY THIS AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 340 AM CST WED DEC 5 2012/
DISCUSSION...
FORECAST CHALLENGE CONCERNS LOW PCPN CHANCES LATE AFTERNOON INTO
TONIGHT...WIND AND TEMPERATURES.
MODELS OVERALL IN FAIR AGREEMENT AND WILL USE BLEND.
NEXT SHORTWAVE CROSSING NORTHERN ROCKIES WILL SPREAD ACROSS FA LATE
THIS AFTERNOON INTO TONIGHT. AS ASSOCIATED COLD FRONT APPROACHES
LATE THIS AFTERNOON MODELS PAINTING SOME LIGHT QPF ENTERING FA.
BASED ON GOOD MODEL AGREEMENT WILL DELAY ANY CHANCES UNTIL CLOSER TO
EVENING. MOISTURE THROUGH COLUMN NOT VERY IMPRESSIVE SO WILL NOT BE
INCREASING POPS. UNTIL THEN MIXING/WARM ADVECTION INCREASES DURING
THE DAY. WILL BE BREEZY TO WINDY HOWEVER NOT ANTICIPATING ADVISORY
CRITERIA WINDS AS MIXED LAYER VERY SHALLOW WITH STEEP INVERSION.
MOST WARM ADVECTION TODAY WILL BE ALOFT HOWEVER WITH MIXING/FILTERED
SOLAR AND LACK OF SNOW COVER TEMPERATURES ACROSS NORTH SHOULD RANGE
AROUND FREEZING AND CLOSE TO 40 ACROSS THE SOUTH. SURFACE
TEMPERATURES WILL DETERMINE WHETHER ANY PCPN WILL BE -SHRA OR PATCHY
FREEZING RAIN LATER TODAY.
COLD FRONT SCOOTS ACROSS FA TONIGHT. MODELS CONTINUE TO SHOW QUICK
SHOT OF PCPN ALONG AND AHEAD OF BOUNDARY. MOISTURE CONTINUES TO LOOK
VERY LIMITED BASED ON SOUNDING PROFILES. BEST CHANCES FOR ANY
FREEZING PCPN LOOKS TO BE ACROSS THE NORTH CLOSER TO UPPER SUPPORT.
ANY PCPN WHICH DOES OCCUR LOOKS TO BE LIGHT AND QUICK MOVING SO AT
THIS POINT NOT ANTICIPATING ANY HEADLINES BUT WILL NEED TO MONITOR.
BASED ON TIMING DID BACK UP SLIGHT CHANCE POPS FARTHER WEST BUT
CONFIDENCE LOW. CLOUDS AND MIXING SHOULD OFFSET COLD ADVECTION
KEEPING MINIMUMS RELATIVELY MILD.
HIGH BUILDS IN THURSDAY. COLUMN COOLER AND COULD SEE SOME CU
DEVELOPMENT WITH CONVECTIVE TEMPERATURES AROUND 30F. THIS SHOULD
KEEP TEMPERATURES A FEW DEGREES COOLER THAN TODAY. LACK OF SNOW
COVER ALWAYS A CHALLENGE THIS TIME OF SEASON FOR TEMPERATURES SO
WILL NOT GO AS COOL AS FAVORED GUIDANCE SUGGESTS.
SECONDARY COLD FRONT BEGINS TO PULL COLDER TEMPERATURES SOUTHWARD
THURSDAY NIGHT/FRIDAY WHICH SHOULD KEEP TEMPERATURES CLOSER TO
AVERAGE. WITH SURFACE HIGH PUSHING IN MODELS GENERALLY TRENDING
FARTHER SOUTH WITH NEXT PCPN CHANCES FRIDAY AND HAVE TRIMMED POPS
BACK CLOSER TO THE ND/SD/MN BORDER AREA.
LONG TERM...SATURDAY THROUGH TUESDAY.
GENERAL PATTERN CHANGE WITH LONG WAVE TROUGH OVER THE ROCKIES ON SAT
WILL SHIFT INTO THE PLAINS BY TUE. SPLIT FLOW EXPECTED THIS PERIOD.
UPPER AIR PATTERN AS WELL AS THE LOW LEVEL THERMAL FIELD WERE
FASTER WITH THE ECMWF THAN THE GFS IN BOTH STREAMS. WILL PREFER THE
SLOWER GFS.
WILL SLOW DOWN PRECIPITATION FOR MON. WILL LEAVE THE REST OF THE
PERIOD AS IS FOR PRECIPITATION.
WENT WARMER SAT...MON AND TUE BY A COUPLE DEGREES AND A LITTLE
COOLER FOR SUN.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
ROGERS/VOELKER
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
936 PM EST THU DEC 6 2012
.SYNOPSIS...
INCREASING MOISTURE FROM THE SOUTH WILL COMBINE WITH A COLD FRONT
DROPPING THROUGH THE GREAT LAKES TO PRODUCE WIDESPREAD
PRECIPITATION ACROSS THE AREA THROUGH THE WEEKEND. THE FRONT WILL
OSCILLATE ACROSS THE AREA UNTIL A STRONG LOW PRESSURE SYSTEM
PUSHES IT EASTWARD ON MONDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
SCATTERED SHOWERS ARE BEGINNING TO BECOME A BIT MORE WIDESPREAD
OVER SOUTHEAST HALF OF CWA BUT ARE STILL HIT AND MISS THIS LATER
EVENING. THE COVERAGE OF THE SHOWERS WILL GRADUALLY INCREASE
THROUGH THE NIGHT AS CONVERGENCE AND UPWARD MOTION COMBINE WITH
THE INCREASED MOISTURE BEING PULLED UP FROM THE SOUTH. MODELS ARE
ALL IN PRETTY FAIR AGREEMENT THAT THERE WILL BE AN AXIS OF HIGHER
RAINFALL ALONG THE INDIANA/KENTUCKY BORDER NORTHEAST TO COLUMBUS
FOLOWING I-71 AND THEN EAST TO WHEELING ALONG I-70. RAINFALL AT
TIMES LATER TONIGHT AND MORE TOWARDS TOMORROW WILL BECOME MORE
CONTINUOUS WITH SOME HEAVIER PERIODS AT TIMES.
ENDED UP LOWERING MIN TEMPERATURES OVER THE NORTH TO COOINCIDE
WITH CURRENT READINGS AND EXPECT A GRADUAL MOISTENING AND
SUBSEQUENT WARMING OF THIS AREA THROUGH THE NIGHT.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
THIS ITERATION OF THE FORECAST PACKAGE FOCUSED ON BRINGING MORE
DETAIL INTO THE PRECIPITATION PATTERNS OVER THE NEXT FEW DAYS. THE
06.12Z NAM APPEARS TO BE AN OUTLIER AFTER FRIDAY AND WAS LARGELY
DISCOUNTED. OTHERWISE MODELS ARE IN SIMILAR AGREEMENT UNTIL LATE
SATURDAY...WHEN THERE IS SOME DISAGREEMENT HOW FAR SOUTH THE
FRONT MAKES IT.
THE FOCUS OF RAINFALL ON FRIDAY WILL CONTINUE ALONG AN AXIS FROM
CENTRAL KENTUCKY TO SOUTHEAST OHIO. CONCENTRATED LOW LEVEL FORCING
WILL COMBINE WITH PRECIPITABLE WATER VALUES EXCEEDING 200 PERCENT
OF NORMAL TO PRODUCE A PROLONGED PERIOD OF MODERATE RAIN.
PRECIPITATION ACROSS THE NORTH WILL BE LIGHT UNTIL AN EMBEDDED
DISTURBANCE IN THE WSW FLOW ALOFT PERTURBS A SFC WAVE ALONG FRONT
(WHICH BY THIS TIME HAS STALLED ITS SOUTHERN PROGRESS)...WHICH WILL
APPROACH THE AREA FRIDAY AFTERNOON AND PROVIDE ADDITIONAL LIFT. BY
THAT TIME...EVERYONE HAS AT LEAST CATEGORICAL POPS. WE WILL REMAIN
ON THE WARM SIDE OF THE STALLED FRONT...WHICH WILL SUPPORT ABOVE
NORMAL TEMPERATURES IN THE 50S.
THE LOW CROSSES THE AREA FRIDAY NIGHT. SOME WEAK INSTABILITY IS
DRAWN NORTHWARD AHEAD OF THE LOW. THIS WILL RETURN PRECIPITATION
TO A MORE SHOWERY NATURE AND PERHAPS INCLUDE SOME EMBEDDED RUMBLES
OF THUNDER ACROSS THE SOUTH. LOWS WILL ONLY FALL A HANDFUL OF
DEGREES FROM THE DAYTIME TEMPERATURES.
THE HIGHEST PRECIPITATION CHANCES WILL SINK SOUTH ON SATURDAY AND
SATURDAY NIGHT AS THE AFOREMENTIONED LOW PULLS THE FRONT SLIGHTLY
SOUTHWARD. THE MODELS ARE IN BETTER AGREEMENT ON THIS BREAK IN THE
ACTION (IN THE NORTH ANYWAY)...WHEREAS SOME PREVIOUS FORECASTS
SUGGESTED AN ALL-WEEKEND EVENT. THE 06.12Z GFS IS FARTHEST SOUTH
AND BRINGS IN A GOOD DEAL OF MID LEVEL DRY AIR...EFFECTIVELY
SHUTTING PRECIPITATION OFF ACROSS A GOOD PORTION OF THE AREA.
HOWEVER...I FEEL THE OTHER MODELS ARE MORE REALISTIC TO FOLLOW AT
THIS TIME...AS COPIOUS MOISTURE REMAINS NEAR THE AREA...THE FRONT
IS NEARBY...AND EMBEDDED DISTURBANCES CONTINUE TO TRACK THROUGH
THE FAST FLOW ALOFT. THEREFORE I KEPT LIKELY POPS IN THE SOUTH
FOR THE REMAINDER OF THE PERIOD. COLD AIR IS NOT DIRECTLY TIED TO
THE SFC FRONT AND TEMPERATURES ARE EXPECTED TO REMAIN ABOVE
NORMAL.
BY SATURDAY NIGHT...STORM TOTAL RAINFALL IS EXPECTED TO RANGE FROM
NEAR A HALF INCH IN THE NORTH TO GREATER THAN 1.5 INCHES IN THE
SOUTH. DUE TO THE INITIALLY DRY CONDITIONS...THE LONG DURATION OF
THE EVENT...AND LOW CONFIDENCE OF ANY HEAVY BANDING/REPEATED
DELUGES IN ANY PARTICULAR LOCATION...THE PROBABILITY OF FLOODING
APPEARS LOW AT THIS TIME.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AN ACTIVE AND WET PATTERN WILL CONTINUE FOR THE FIRST HALF OF THE
LONG TERM PERIOD...BEFORE DRIER CONDITIONS SETTLE IN BEHIND A COLD
FRONTAL PASSAGE ON MONDAY.
A BROAD MID-LEVEL TROUGH WILL EXIST ACROSS MOST OF THE CONUS AT THE
START OF THE PERIOD. THIS TROUGH IS CHARACTERIZED BY SEVERAL
SHORTWAVES WITH VARIOUS AMPLITUDES AT DIFFERENT LATITUDES...MOVING
QUICKLY EAST IN THE QUICK FLOW.
A GREATER DEGREE OF SEPARATION BETWEEN THE SHORT TERM SYSTEM (SEE
DISCUSSION ABOVE) AND THE SYSTEM ON SUNDAY AND MONDAY IS BEING
FORECAST BY VARIOUS MODEL RUNS TODAY. A LEFTOVER SURFACE BOUNDARY
WILL BEGIN MOVING NORTH ON SUNDAY...LEADING TO HIGH CHANCES OF
PRECIPITATION AS A VERY MOIST SOUTHERLY FLOW BEGINS.
COLD FRONTAL TIMING HAS COME INTO STRONG AGREEMENT WITH THE 12Z
MODEL SUITE...WITH THE PASSAGE THROUGH THE ILN CWA OCCURRING DURING
THE MORNING HOURS ON MONDAY. THROUGH THIS TIME PERIOD...CATEGORICAL
POPS ARE BEING FORECAST (80-90 PERCENT)...AND THERE APPEARS TO BE
ENOUGH ELEVATED INSTABILITY TO SUPPORT A SLIGHT CHANCE OF THUNDER
(UNTIL THE COLD FRONT MOVES THROUGH). PRECIPITATION WILL LIKELY
EXIST BEHIND THE FRONT AS WELL.
THE MID LEVEL TROUGH THAT WILL FOLLOW THE FRONT (AND ITS ATTACHED
SURFACE LOW MOVING THROUGH THE GREAT LAKES) HAS BEEN MODELED WITH A
FEW SUBTLE DIFFERENCES...PRESENTING SOME CHALLENGES IN THE
PRECIPITATION FORECAST ON THE BACK SIDE OF THE FRONT. THOUGH ONE
AXIS CAN BE DEPICTED NEAR AND ASSOCIATED WITH THE PRIMARY SURFACE
LOW...THE 12Z ECMWF DEPICTS A SHARPER AXIS WITH THE BASE OF THE
TROUGH BEHIND THE COLD FRONT. THIS LEADS TO THE GENESIS OF A SURFACE
LOW OVER THE TENNESSEE VALLEY AND SOUTHERN APPALACHIANS...WHICH HAS
ENOUGH OF AN IMPACT OVER OUR REGION TO SPREAD ADDITIONAL
PRECIPITATION IN BEHIND THE FRONT. THIS FEATURE IS ALSO SHOWN ON THE
12Z GFS...THOUGH IT IS NOT AS AMPLIFIED. IF THIS OCCURS...THE
CHANCES OF SNOW WILL INCREASE...AS TEMPERATURES MONDAY NIGHT ARE
CERTAINLY COLD ENOUGH TO SUPPORT SNOW AS THE PRIMARY (OR ONLY)
PRECIPITATION TYPE.
IN ADDITION TO THE 0.5-1.5 INCHES OF RAINFALL FORECAST IN THE SHORT
TERM...AN ADDITIONAL SIMILAR AMOUNT IS EXPECTED DURING THE SYSTEM ON
SUNDAY AND MONDAY. GIVEN THE PROLONGED NATURE OF THE PAIR OF
EVENTS...AND THE BREAK IN BETWEEN THE TWO...WIDESPREAD FLOODING
STILL APPEARS UNLIKELY. IT IS MUCH TOO EARLY TO FOCUS ON THE
POSSIBILITIES OF CONVECTIVE OR MESOSCALE FEATURES ENHANCING THE
FLOOD THREAT IN CERTAIN LOCATIONS.
THE TEMPERATURE FORECAST THROUGH THE PERIOD IS FAIRLY MILD ASIDE
FROM DIRECTLY BEHIND THE FRONT. A NON-DIURNAL TEMPERATURE TRACE
(WITH A VERY SHARP GRADIENT) WAS DRAWN IN FOR SUNDAY NIGHT THROUGH
MONDAY NIGHT. BY THE MIDDLE OF THE WEEK...HIGH PRESSURE NOSING IN
FROM THE SOUTH WILL ALLOW SOUTHWESTERLY FLOW TO BRING TEMPERATURES
NEAR AND THEN ABOVE NORMAL ONCE AGAIN.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
WHILE NOT EXTREME IN COVERAGE BY ANY SENSE...SCATTERED SHOWERS
OVER KY WILL CONTINUE TO STREAM NORTHEAST INTO OHIO AND THE TAF
SITES THIS EVENING AS THEY INCREASE IN AREA. USED THE HRRR MODEL
TO TRY TO LIMIT THE ONSET OF THE SHOWERS TO MORE AFTER 4Z IN THE
SOUTH AND THEN NOT HAVE THEM PREVAIL UNTIL 9Z. TIMING IS SLIGHTLY
LATER IN THE NORTH AND A GOOD BIT OF THE SHOWERS COULD SKIP DAYTON
AND POSSIBLY WILMINGTON UNTIL DAYBREAK. ONCE THE ATMOSPHERE
MOISTENS UP HOWEVER...THE RAIN WILL PREVAIL AND LOW CIGS AND
REDUCE VSBYS WILL GO FROM MVFR TO IFR GRADUALLY THROUGH THE DAY.
OUTLOOK...MVFR/IFR CIGS AND VSBYS POSSIBLE FRIDAY AFTERNOON INTO MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...SNYDER
NEAR TERM...FRANKS/SNYDER
SHORT TERM...SNYDER
LONG TERM...HATZOS
AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
731 PM EST THU DEC 6 2012
.SYNOPSIS...
INCREASING MOISTURE FROM THE SOUTH WILL COMBINE WITH A COLD FRONT
DROPPING THROUGH THE GREAT LAKES TO PRODUCE WIDESPREAD
PRECIPITATION ACROSS THE AREA THROUGH THE WEEKEND. THE FRONT WILL
OSCILLATE ACROSS THE AREA UNTIL A STRONG LOW PRESSURE SYSTEM
PUSHES IT EASTWARD ON MONDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE REGION WILL REMAIN IN A RETURN FLOW PATTERN TONIGHT AROUND
HIGH PRESSURE LOCATED ALONG THE EAST COAST. THIS WILL DRAW
INCREASING MOISTURE FROM THE GULF OF MEXICO INTO THE REGION.
A LOW LEVEL JET WILL BEGIN TO FOCUS THIS MOISTURE ALONG THE OHIO
RIVER LATE THIS EVENING AND THROUGH THE OVERNIGHT HOURS. MEANWHILE
THE LEFT EXIT REGION OF THE SUBTROPICAL JET WILL APPROACH THE AREA
AS A BROAD UPPER LEVEL TROUGH BEGINS TO BE CARVED OUT ACROSS THE
CENTRAL CONUS. INITIALLY SHOWERY PRECIPITATION WILL BECOME MORE
WIDESPREAD AS THE MOISTURE AND ASCENT INCREASE...SETTING UP A
PSEUDO-WARM FRONT. THE ACTUAL COLD FRONT TRAILING LOW PRESSURE
WELL TO THE NORTH IN CANADA WILL STAY TO OUR NORTHWEST TONIGHT.
OUR NORTHERN COUNTIES MAY STAY DRY UNTIL THESE TWO AREAS OF ASCENT
CONVERGE ON FRIDAY...ALTHOUGH A FEW SHOWERS CANNOT BE TOTALLY
RULED OUT LATER TONIGHT. TEMPERATURES WILL HOLD NEARLY STEADY IN
THE UPPER 40S TO NEAR 50 IN THE SOUTH TONIGHT. SOME UPPER 30S
COULD BE FOUND ACROSS THE NORTH WHERE CLOUDS AND DEW POINTS WILL
BE LAST TO INCREASE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
THIS ITERATION OF THE FORECAST PACKAGE FOCUSED ON BRINGING MORE
DETAIL INTO THE PRECIPITATION PATTERNS OVER THE NEXT FEW DAYS. THE
06.12Z NAM APPEARS TO BE AN OUTLIER AFTER FRIDAY AND WAS LARGELY
DISCOUNTED. OTHERWISE MODELS ARE IN SIMILAR AGREEMENT UNTIL LATE
SATURDAY...WHEN THERE IS SOME DISAGREEMENT HOW FAR SOUTH THE
FRONT MAKES IT.
THE FOCUS OF RAINFALL ON FRIDAY WILL CONTINUE ALONG AN AXIS FROM
CENTRAL KENTUCKY TO SOUTHEAST OHIO. CONCENTRATED LOW LEVEL FORCING
WILL COMBINE WITH PRECIPITABLE WATER VALUES EXCEEDING 200 PERCENT
OF NORMAL TO PRODUCE A PROLONGED PERIOD OF MODERATE RAIN.
PRECIPITATION ACROSS THE NORTH WILL BE LIGHT UNTIL AN EMBEDDED
DISTURBANCE IN THE WSW FLOW ALOFT PERTURBS A SFC WAVE ALONG FRONT
(WHICH BY THIS TIME HAS STALLED ITS SOUTHERN PROGRESS)...WHICH WILL
APPROACH THE AREA FRIDAY AFTERNOON AND PROVIDE ADDITIONAL LIFT. BY
THAT TIME...EVERYONE HAS AT LEAST CATEGORICAL POPS. WE WILL REMAIN
ON THE WARM SIDE OF THE STALLED FRONT...WHICH WILL SUPPORT ABOVE
NORMAL TEMPERATURES IN THE 50S.
THE LOW CROSSES THE AREA FRIDAY NIGHT. SOME WEAK INSTABILITY IS
DRAWN NORTHWARD AHEAD OF THE LOW. THIS WILL RETURN PRECIPITATION
TO A MORE SHOWERY NATURE AND PERHAPS INCLUDE SOME EMBEDDED RUMBLES
OF THUNDER ACROSS THE SOUTH. LOWS WILL ONLY FALL A HANDFUL OF
DEGREES FROM THE DAYTIME TEMPERATURES.
THE HIGHEST PRECIPITATION CHANCES WILL SINK SOUTH ON SATURDAY AND
SATURDAY NIGHT AS THE AFOREMENTIONED LOW PULLS THE FRONT SLIGHTLY
SOUTHWARD. THE MODELS ARE IN BETTER AGREEMENT ON THIS BREAK IN THE
ACTION (IN THE NORTH ANYWAY)...WHEREAS SOME PREVIOUS FORECASTS
SUGGESTED AN ALL-WEEKEND EVENT. THE 06.12Z GFS IS FARTHEST SOUTH
AND BRINGS IN A GOOD DEAL OF MID LEVEL DRY AIR...EFFECTIVELY
SHUTTING PRECIPITATION OFF ACROSS A GOOD PORTION OF THE AREA.
HOWEVER...I FEEL THE OTHER MODELS ARE MORE REALISTIC TO FOLLOW AT
THIS TIME...AS COPIOUS MOISTURE REMAINS NEAR THE AREA...THE FRONT
IS NEARBY...AND EMBEDDED DISTURBANCES CONTINUE TO TRACK THROUGH
THE FAST FLOW ALOFT. THEREFORE I KEPT LIKELY POPS IN THE SOUTH
FOR THE REMAINDER OF THE PERIOD. COLD AIR IS NOT DIRECTLY TIED TO
THE SFC FRONT AND TEMPERATURES ARE EXPECTED TO REMAIN ABOVE
NORMAL.
BY SATURDAY NIGHT...STORM TOTAL RAINFALL IS EXPECTED TO RANGE FROM
NEAR A HALF INCH IN THE NORTH TO GREATER THAN 1.5 INCHES IN THE
SOUTH. DUE TO THE INITIALLY DRY CONDITIONS...THE LONG DURATION OF
THE EVENT...AND LOW CONFIDENCE OF ANY HEAVY BANDING/REPEATED
DELUGES IN ANY PARTICULAR LOCATION...THE PROBABILITY OF FLOODING
APPEARS LOW AT THIS TIME.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AN ACTIVE AND WET PATTERN WILL CONTINUE FOR THE FIRST HALF OF THE
LONG TERM PERIOD...BEFORE DRIER CONDITIONS SETTLE IN BEHIND A COLD
FRONTAL PASSAGE ON MONDAY.
A BROAD MID-LEVEL TROUGH WILL EXIST ACROSS MOST OF THE CONUS AT THE
START OF THE PERIOD. THIS TROUGH IS CHARACTERIZED BY SEVERAL
SHORTWAVES WITH VARIOUS AMPLITUDES AT DIFFERENT LATITUDES...MOVING
QUICKLY EAST IN THE QUICK FLOW.
A GREATER DEGREE OF SEPARATION BETWEEN THE SHORT TERM SYSTEM (SEE
DISCUSSION ABOVE) AND THE SYSTEM ON SUNDAY AND MONDAY IS BEING
FORECAST BY VARIOUS MODEL RUNS TODAY. A LEFTOVER SURFACE BOUNDARY
WILL BEGIN MOVING NORTH ON SUNDAY...LEADING TO HIGH CHANCES OF
PRECIPITATION AS A VERY MOIST SOUTHERLY FLOW BEGINS.
COLD FRONTAL TIMING HAS COME INTO STRONG AGREEMENT WITH THE 12Z
MODEL SUITE...WITH THE PASSAGE THROUGH THE ILN CWA OCCURRING DURING
THE MORNING HOURS ON MONDAY. THROUGH THIS TIME PERIOD...CATEGORICAL
POPS ARE BEING FORECAST (80-90 PERCENT)...AND THERE APPEARS TO BE
ENOUGH ELEVATED INSTABILITY TO SUPPORT A SLIGHT CHANCE OF THUNDER
(UNTIL THE COLD FRONT MOVES THROUGH). PRECIPITATION WILL LIKELY
EXIST BEHIND THE FRONT AS WELL.
THE MID LEVEL TROUGH THAT WILL FOLLOW THE FRONT (AND ITS ATTACHED
SURFACE LOW MOVING THROUGH THE GREAT LAKES) HAS BEEN MODELED WITH A
FEW SUBTLE DIFFERENCES...PRESENTING SOME CHALLENGES IN THE
PRECIPITATION FORECAST ON THE BACK SIDE OF THE FRONT. THOUGH ONE
AXIS CAN BE DEPICTED NEAR AND ASSOCIATED WITH THE PRIMARY SURFACE
LOW...THE 12Z ECMWF DEPICTS A SHARPER AXIS WITH THE BASE OF THE
TROUGH BEHIND THE COLD FRONT. THIS LEADS TO THE GENESIS OF A SURFACE
LOW OVER THE TENNESSEE VALLEY AND SOUTHERN APPALACHIANS...WHICH HAS
ENOUGH OF AN IMPACT OVER OUR REGION TO SPREAD ADDITIONAL
PRECIPITATION IN BEHIND THE FRONT. THIS FEATURE IS ALSO SHOWN ON THE
12Z GFS...THOUGH IT IS NOT AS AMPLIFIED. IF THIS OCCURS...THE
CHANCES OF SNOW WILL INCREASE...AS TEMPERATURES MONDAY NIGHT ARE
CERTAINLY COLD ENOUGH TO SUPPORT SNOW AS THE PRIMARY (OR ONLY)
PRECIPITATION TYPE.
IN ADDITION TO THE 0.5-1.5 INCHES OF RAINFALL FORECAST IN THE SHORT
TERM...AN ADDITIONAL SIMILAR AMOUNT IS EXPECTED DURING THE SYSTEM ON
SUNDAY AND MONDAY. GIVEN THE PROLONGED NATURE OF THE PAIR OF
EVENTS...AND THE BREAK IN BETWEEN THE TWO...WIDESPREAD FLOODING
STILL APPEARS UNLIKELY. IT IS MUCH TOO EARLY TO FOCUS ON THE
POSSIBILITIES OF CONVECTIVE OR MESOSCALE FEATURES ENHANCING THE
FLOOD THREAT IN CERTAIN LOCATIONS.
THE TEMPERATURE FORECAST THROUGH THE PERIOD IS FAIRLY MILD ASIDE
FROM DIRECTLY BEHIND THE FRONT. A NON-DIURNAL TEMPERATURE TRACE
(WITH A VERY SHARP GRADIENT) WAS DRAWN IN FOR SUNDAY NIGHT THROUGH
MONDAY NIGHT. BY THE MIDDLE OF THE WEEK...HIGH PRESSURE NOSING IN
FROM THE SOUTH WILL ALLOW SOUTHWESTERLY FLOW TO BRING TEMPERATURES
NEAR AND THEN ABOVE NORMAL ONCE AGAIN.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
WHILE NOT EXTREME IN COVERAGE BY ANY SENSE...SCATTERED SHOWERS
OVER KY WILL CONTINUE TO STREAM NORTHEAST INTO OHIO AND THE TAF
SITES THIS EVENING AS THEY INCREASE IN AREA. USED THE HRRR MODEL
TO TRY TO LIMIT THE ONSET OF THE SHOWERS TO MORE AFTER 4Z IN THE
SOUTH AND THEN NOT HAVE THEM PREVAIL UNTIL 9Z. TIMING IS SLIGHTLY
LATER IN THE NORTH AND A GOOD BIT OF THE SHOWERS COULD SKIP DAYTON
AND POSSIBLY WILMINGTON UNTIL DAYBREAK. ONCE THE ATMOSPHERE
MOISTENS UP HOWEVER...THE RAIN WILL PREVAIL AND LOW CIGS AND
REDUCE VSBYS WILL GO FROM MVFR TO IFR GRADUALLY THROUGH THE DAY.
OUTLOOK...MVFR/IFR CIGS AND VSBYS POSSIBLE FRIDAY AFTERNOON INTO MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...SNYDER
NEAR TERM...SNYDER
SHORT TERM...SNYDER
LONG TERM...HATZOS
AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1050 PM EST THU DEC 6 2012
.SYNOPSIS...
A COLD FRONTAL BOUNDARY OVER THE UPPER GREAT LAKES AND MID
MISSISSIPPI VALLEY WILL DRIFT SOUTHEAST AND STALL OUT FROM THE OHIO
VALLEY TO PENNSYLVANIA FOR THE WEEKEND. WHILE THIS WILL BE A
RELATIVELY MILD PERIOD...IT WILL ALSO BE A WET PATTERN AS A FEW
WAVES OF LOW PRESSURE RIPPLE NORTHEAST ALONG THE FRONTAL BOUNDARY.
A STRONG COLD FRONTAL PASSAGE ON MONDAY WILL RETURN TEMPERATURES TO
SEASONAL NORMALS DURING THE FIRST PART OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 7 AM FRIDAY MORNING/...
A HIGH CLOUD SHIELD HAS SPREAD ACROSS ALL OF CENTRAL AND WESTERN
PENN...AND WILL LOWER/THICKEN-UP LATE TONIGHT.
THIN SPOTS IN THE HIGH OVC ACROSS THE EASTERN HALF OF THE CWA WILL
ALLOW TEMPS TO COOL OFF MOST THERE. MIN TEMPS AROUND DAYBREAK WILL
BE IN THE MID 20S ACROSS THE NCENT MTNS AND MIDDLE SUSQ VALLEY...AND
28-30F THROUGHOUT THE CENTRAL MTNS AND LOWER SUSQ REGION. SIMILAR
MIN TEMPS IN THE UPPER 20S TO AROUND 30F ACROSS THE WESTERN MTNS
WILL OCCUR SHORTLY AFTER MIDNIGHT...THEN JUMP DURING THE PREDAWN
HOURS AS A SSE SFC WIND FRESHENS TO 6-8KTS AND MIXES UP/BREAKS
THE SHALLOW LLVL INVERSION.
WEAK ISENTROPIC LIFT WITHIN THE 285-295K THETA LAYER WILL DEVELOP
AFTER 06Z ACROSS THE WESTERN PORTIONS OF THE CWA...AND THROUGHOUT
THE CENTRAL MTNS BEGINNING AROUND 09Z. THE NOSE OF ONE-INCH PWAT AIR
WILL BE ADVECTING NE FROM THE MIDDLE OHIO RIVER VALLEY IN THE 06-12Z
PERIOD VIA A MEAN LLVL SWRLY 20-30KT FLOW.
THIS LIFT AND INCREASING MOISTURE...COMBINED WITH MEAN WET BULB
TEMPS CLIMBING TO A FEW TO SVRL DEG C ABOVE ZERO IN THAT SAME LAYER
WILL CAUSE PRECIP TO FALL TWD THE SFC AS PLAIN RAIN ACROSS THE
WESTERN MTNS.
LOWER/COOLER MEMBERS OF THE SREF PLUMES...AND THE LATEST HRRR AND
NAM SFC WET BULBS...INDICATE THAT POCKETS OF SLIGHTLY SUB-FREEZING
TEMPS WILL OCCUR THROUGHOUT THE CENTRAL/NRN MTNS AND MIDDLE SUSQ
REGION AS LIGHT PRECIP STREAMS IN DURING THE EARLY TO MID MORNING
HOURS FRIDAY. THIS WILL CREATE THE THREAT FOR A THIN GLAZING OF
FREEZING RAIN ON COLDER/UNTREATED SFCS. THE SFC TEMPS SHOULD ONLY BE
AOB FZG FOR A 2-3 HR PERIOD WHEN THE LIGHT RAIN IS FALLING.
THE WESTERN MTS WILL MOST LIKELY BE SLIGHTLY ABOVE FREEZING WHEN THE
RAIN ARRIVES AFTER 06Z FRI...SO WILL CONTINUE WITH NO ADVY THERE.
&&
.SHORT TERM /7 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
TEMPS WILL WARM ENOUGH TO ELIMINATE ANY THREAT FOR FZRA/ICE ACCUM IN
THE MORNING. RAIN/INCREASING LLVL DEWPOINTS WILL WILL MAKE IT
SOMEWHAT FOGGY ON THE RIDGES DURING THE DAY AND INTO THE NIGHT.
TEMPS WILL BE SLIGHTLY COOLER THAN NORMAL FRIDAY WITHOUT MUCH SOLAR
HEATING.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
ENTERING INTO THE LONG TERM PERIOD...SOUTHWESTERLY FLOW WILL
DOMINATE THE PATTERN AND PERSIST INTO EARLY NEXT.
A WEAK TROUGH WILL PROPAGATE THROUGH THE REGION AS A VIGOROUS
PACIFIC DISTURBANCE COMING ONSHORE OVER WESTERN BRITISH COLUMBIA
ON FRIDAY WILL DIG INTO THE CENTRAL AND NORTHERN U.S. ROCKIES THIS
WEEKEND. THIS WILL BEGIN ITS TREK THROUGH THE EAST EARLY NEXT
WEEK.
WHILE CONSIDERABLE UNCERTAINTY REMAINS OVER THE EVOLUTION OF THE
FLOW PATTERN FOR THE EARLY TO MIDDLE OF NEXT WEEK...THE MAIN FOCUS OF
THE LONG TERM PATTERN WILL BE A CONTINUATION OF ABOVE NORMAL
TEMPERATURES AND TRANSITION TO A WETTER PATTERN THIS WEEKEND.
WHAT HAS BEEN MOST CONSISTENT OVER THE PAST FEW DAYS...HAS BEEN
THE SOLUTION THAT A FRONT WILL APPROACH/CROSS INTO PA BY SATURDAY
AND CONTINUE TO REMAIN ACROSS THE STATE INTO SUNDAY. THIS WILL BE
FOLLOWED BY A SECOND COLD FRONT MOVING ACROSS THE STATE ON MONDAY.
THIS WILL BRING THE LONGEST STRETCH OF WET WEATHER TO THE
COMMONWEALTH. EXPECT THE PRECIPITATION TO BE RAIN THROUGH THIS
PERIOD...WITH COLDER AIR FILLING IN BEHIND THE FRONT MONDAY NIGHT
INTO TUESDAY. THIS WILL BRING TEMPERATURES BACK TO AROUND
NORMAL...WITH NORTHWEST FLOW BEHIND THE FRONT...LAKE ENHANCED SNOW
WILL BE POSSIBLE.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
SFC HIGH PRESSURE WILL MAINTAIN VFR FLYING OVER CENTRAL PA
AIRSPACE INTO TONIGHT. A MOISTENING RETURN FLOW ON THE BACKSIDE
OF THE DEPARTING SFC HIGH WILL INTERACT WITH AN APPROACHING UPPER
LEVEL TROUGH TO PRODUCE A THICKENING/LOWERING CLOUD DECK LATE
TONIGHT WITH RAIN ARRIVING ARND DAWN. TEMPS MAY BE JUST COLD
ENOUGH AT GROUND LEVEL TO SUPPORT AN INITIAL PERIOD OF FZRA BTWN
09Z-14Z FOR AREAS NORTH AND WEST OF MDT.
THE MOIST...SERLY FLOW WILL INTERACT WITH A DYING COLD FRONT
APPROACHING FROM THE GRT LKS TO PRODUCE PERIODS OF RAIN DURING THE
DAYLIGHT HRS OF FRIDAY. LATEST MDL DATA SUGGESTS THE STEADIEST
RAIN WILL FALL ACROSS THE NORTHERN HALF OF THE STATE...WHERE SREF
DATA SUPPORTS IFR CONDS. ACROSS THE SOUTH...MVFR CONDS APPEAR MORE
LIKELY.
OUTLOOK...
SAT...AM -RA/LOW CIGS/VSBYS...THEN IMPROVEMENT BY AFTN ESP SOUTH.
SUN...AM FOG POSSIBLE. RAIN/LOW CIGS POSSIBLE LATE.
MON...RAIN/LOW CIGS POSSIBLE...ESP W MTNS.
TUE...SLIGHT CHC OF RAIN OR SNOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY FROM 6 AM TO 11 AM EST FRIDAY FOR
PAZ006-011-012-037-041-042-045-046-049>053-058.
FREEZING RAIN ADVISORY FROM 4 AM TO 9 AM EST FRIDAY FOR PAZ018-
019-025>028-034-035.
&&
$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...DANGELO
LONG TERM...DEVOIR/CERU
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
919 PM EST THU DEC 6 2012
.SYNOPSIS...
A COLD FRONTAL BOUNDARY OVER THE UPPER GREAT LAKES AND MID
MISSISSIPPI VALLEY WILL DRIFT SOUTHEAST AND STALL OUT FROM THE OHIO
VALLEY TO PENNSYLVANIA FOR THE WEEKEND. WHILE THIS WILL BE A
RELATIVELY MILD PERIOD...IT WILL ALSO BE A WET PATTERN AS A FEW
WAVES OF LOW PRESSURE RIPPLE NORTHEAST ALONG THE FRONTAL BOUNDARY.
A STRONG COLD FRONTAL PASSAGE ON MONDAY WILL RETURN TEMPERATURES TO
SEASONAL NORMALS DURING THE FIRST PART OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 7 AM FRIDAY MORNING/...
A HIGH CLOUD SHIELD HAS SPREAD ACROSS ALL OF CENTRAL AND WESTERN
PENN...AND WILL LOWER/THICKEN-UP LATE TONIGHT.
THIN SPOTS IN THE HIGH OVC ACROSS THE EASTERN HALF OF THE CWA WILL
ALLOW TEMPS TO COOL OFF MOST THERE. MIN TEMPS AROUND DAYBREAK WILL
BE IN THE MID 20S ACROSS THE NCENT MTNS AND MIDDLE SUSQ VALLEY...AND
28-30F THROUGHOUT THE CENTRAL MTNS AND LOWER SUSQ REGION. SIMILAR
MIN TEMPS IN THE UPPER 20S TO AROUND 30F ACROSS THE WESTERN MTNS
WILL OCCUR SHORTLY AFTER MIDNIGHT...THEN JUMP DURING THE PREDAWN
HOURS AS A SSE SFC WIND FRESHENS TO 6-8KTS AND MIXES UP/BREAKS
THE SHALLOW LLVL INVERSION.
WEAK ISENTROPIC LIFT WITHIN THE 285-295K THETA LAYER WILL DEVELOP
AFTER 06Z ACROSS THE WESTERN PORTIONS OF THE CWA...AND THROUGHOUT
THE CENTRAL MTNS BEGINNING AROUND 09Z. THE NOSE OF ONE-INCH PWAT AIR
WILL BE ADVECTING NE FROM THE MIDDLE OHIO RIVER VALLEY IN THE 06-12Z
PERIOD VIA A MEAN LLVL SWRLY 20-30KT FLOW.
THIS LIFT AND INCREASING MOISTURE...COMBINED WITH MEAN WET BULB
TEMPS CLIMBING TO A FEW TO SVRL DEG C ABOVE ZERO IN THAT SAME LAYER
WILL CAUSE PRECIP TO FALL TWD THE SFC AS PLAIN RAIN ACROSS THE
WESTERN MTNS.
LOWER/COOLER MEMBERS OF THE SREF PLUMES...AND THE LATEST HRRR AND
NAM SFC WET BULBS...INDICATE THAT POCKETS OF SLIGHTLY SUB-FREEZING
TEMPS WILL OCCUR THROUGHOUT THE CENTRAL/NRN MTNS AND MIDDLE SUSQ
REGION AS LIGHT PRECIP STREAMS IN DURING THE EARLY TO MID MORNING
HOURS FRIDAY. THIS WILL CREATE THE THREAT FOR A THIN GLAZING OF
FREEZING RAIN ON COLDER/UNTREATED SFCS. THE SFC TEMPS SHOULD ONLY BE
AOB FZG FOR A 2-3 HR PERIOD WHEN THE LIGHT RAIN IS FALLING.
THE WESTERN MTS WILL MOST LIKELY BE SLIGHTLY ABOVE FREEZING WHEN THE
RAIN ARRIVES AFTER 06Z FRI...SO WILL CONTINUE WITH NO ADVY THERE.
&&
.SHORT TERM /7 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
TEMPS WILL WARM ENOUGH TO ELIMINATE ANY THREAT FOR FZRA/ICE ACCUM IN
THE MORNING. RAIN/INCREASING LLVL DEWPOINTS WILL WILL MAKE IT
SOMEWHAT FOGGY ON THE RIDGES DURING THE DAY AND INTO THE NIGHT.
TEMPS WILL BE SLIGHTLY COOLER THAN NORMAL FRIDAY WITHOUT MUCH SOLAR
HEATING.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
ENTERING INTO THE LONG TERM PERIOD...SOUTHWESTERLY FLOW WILL
DOMINATE THE PATTERN AND PERSIST INTO EARLY NEXT.
A WEAK TROUGH WILL PROPAGATE THROUGH THE REGION AS A VIGOROUS
PACIFIC DISTURBANCE COMING ONSHORE OVER WESTERN BRITISH COLUMBIA
ON FRIDAY WILL DIG INTO THE CENTRAL AND NORTHERN U.S. ROCKIES THIS
WEEKEND. THIS WILL BEGIN ITS TREK THROUGH THE EAST EARLY NEXT
WEEK.
WHILE CONSIDERABLE UNCERTAINTY REMAINS OVER THE EVOLUTION OF THE
FLOW PATTERN FOR THE EARLY TO MIDDLE OF NEXT WEEK...THE MAIN FOCUS OF
THE LONG TERM PATTERN WILL BE A CONTINUATION OF ABOVE NORMAL
TEMPERATURES AND TRANSITION TO A WETTER PATTERN THIS WEEKEND.
WHAT HAS BEEN MOST CONSISTENT OVER THE PAST FEW DAYS...HAS BEEN
THE SOLUTION THAT A FRONT WILL APPROACH/CROSS INTO PA BY SATURDAY
AND CONTINUE TO REMAIN ACROSS THE STATE INTO SUNDAY. THIS WILL BE
FOLLOWED BY A SECOND COLD FRONT MOVING ACROSS THE STATE ON MONDAY.
THIS WILL BRING THE LONGEST STRETCH OF WET WEATHER TO THE
COMMONWEALTH. EXPECT THE PRECIPITATION TO BE RAIN THROUGH THIS
PERIOD...WITH COLDER AIR FILLING IN BEHIND THE FRONT MONDAY NIGHT
INTO TUESDAY. THIS WILL BRING TEMPERATURES BACK TO AROUND
NORMAL...WITH NORTHWEST FLOW BEHIND THE FRONT...LAKE ENHANCED SNOW
WILL BE POSSIBLE.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
SFC HIGH PRESSURE WILL MAINTAIN VFR FLYING OVER CENTRAL PA
AIRSPACE INTO TONIGHT. A MOISTENING RETURN FLOW ON THE BACKSIDE
OF THE DEPARTING SFC HIGH WILL INTERACT WITH AN APPROACHING UPPER
LEVEL TROUGH TO PRODUCE A THICKENING/LOWERING CLOUD DECK LATE
TONIGHT WITH RAIN ARRIVING ARND DAWN. TEMPS MAY BE JUST COLD
ENOUGH AT GROUND LEVEL TO SUPPORT AN INITIAL PERIOD OF FZRA BTWN
09Z-14Z FOR AREAS NORTH AND WEST OF MDT.
THE MOIST...SERLY FLOW WILL INTERACT WITH A DYING COLD FRONT
APPROACHING FROM THE GRT LKS TO PRODUCE PERIODS OF RAIN DURING THE
DAYLIGHT HRS OF FRIDAY. LATEST MDL DATA SUGGESTS THE STEADIEST
RAIN WILL FALL ACROSS THE NORTHERN HALF OF THE STATE...WHERE SREF
DATA SUPPORTS IFR CONDS. ACROSS THE SOUTH...MVFR CONDS APPEAR MORE
LIKELY.
OUTLOOK...
SAT...AM -RA/LOW CIGS/VSBYS...THEN IMPROVEMENT BY AFTN ESP SOUTH.
SUN...AM FOG POSSIBLE. RAIN/LOW CIGS POSSIBLE LATE.
MON...RAIN/LOW CIGS POSSIBLE...ESP W MTNS.
TUE...SLIGHT CHC OF RAIN OR SNOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY FROM 6 AM TO 11 AM EST FRIDAY FOR
PAZ006-011-012-037-041-042-045-046-049>053-058.
FREEZING RAIN ADVISORY FROM 4 AM TO 9 AM EST FRIDAY FOR PAZ018-
019-025>028-034-035.
&&
$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT/DANGELO
LONG TERM...DEVOIR/CERU
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
255 PM EST WED DEC 5 2012
.SYNOPSIS...
A COLD FRONT WILL REACH THE SOUTH CAROLINA COAST THIS EVENING. HIGH
PRESSURE WILL RETURN OVER THE AREA FOR THURSDAY AND FRIDAY. EXPECT
THIS HIGH TO BECOME CENTERED OFF THE EAST COAST WHICH WILL RESULT IN
A STRONG SOUTHERLY FLOW OF WARM AND MOIST AIR OVER THE WEEKEND.
ANOTHER COLD FRONT WILL APPROACH THE REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AT 230 PM... FOR THE REMAINDER OF THE AFTERNOON... SHOWERS AND
POSSIBLY AN ISOLATED THUNDERSTORM OR TWO WILL ADVANCE ACROSS THE
PIEDMONT AS THE LEADING EDGE OF THE FRONTAL BOUNDARY SINKS SLOWLY
SOUTHWARD THROUGH THE SOUTH CAROLINA ZONES. RAP INDICATES SURFACE
DEWPOINTS CLOSE TO 60 DEGREES WILL POOL IN THE UPSTATE DUE TO
CONVERGENCE IN THE FRONTAL ZONE. THIS IS THE AREA WITH CAPES IN THE
150 TO 300 J/KG RANGE. THUS... ANY THUNDER THAT DOES OCCUR IS MOST
LIKELY ACROSS THE SOUTHERN PIEDMONT OF NORTH CAROLINA AND THE
UPSTATE OF SOUTH CAROLINA THROUGH EARLY EVENING. OTHERWISE... DRIER
AIR WILL SPREAD INTO THE NORTHERN ZONES AND PARTIAL CLEARING WILL
OCCUR THERE TONIGHT.
500 MB FLOW ACROSS THE CWA DURING THE NEAR TERM PART OF THE FORECAST
WILL BE PRIMARILY FROM THE WEST. THE TROUGH ALOFT MOVING ACROSS THE
GULF OF MEXICO TONIGHT AND THURSDAY WILL NOT BE A MAJOR PLAYER IN
OUR WEATHER. A STRONG SHORT WAVE TROUGH MOVING THROUGH NEW ENGLAND
AND EASTERN CANADA WILL BE THE MAIN FEATURE PUSHING THE COLD FRONT
SOUTH OF THE AREA THIS EVENING. SURFACE HIGH BEHIND THE FRONT WILL
BE OVER THE GREAT LAKES THIS EVENING MOVING TO A POSITION OVER THE
MID-ATLANTIC STATES AND NEW ENGLAND THURSDAY AFTERNOON. THE COLD AIR
DAMMING PATTERN THAT DEVELOPS WILL RESULT IN A NORTHEAST WIND AND
TEMPERATURES TOMORROW THAT ARE MUCH CLOSER TO NORMAL THAN THE
TEMPERATURES OF RECENT DAYS. BY THE END OF THE PERIOD... THE HIGH
CENTER IS ALREADY SHOWING SIGNS OF DRIFTING OFFSHORE... BUT THE
SOUTHWESTERN NOSE OF THE HIGH WILL CONTINUE TO EXTEND SOUTHWESTWARD
INT THE CWA DURING EARLY EVENING THURSDAY. THE FRONTAL ZONE TO OUR
SOUTH WILL NEVER QUITE CLEAR THE FAR WESTERN ZONES AND THE AIR MASS
CHANGE THERE WILL BE LESS NOTICEABLE THAN EAST OF THE MOUNTAINS.
QUITE A BIT OF FRONTAL ZONE MOISTURE WILL REMAIN OVER THE AREA...
BUT NORTHERN ZONES WILL HAVE A PERIOD OF NEARLY CLOUD FREE SKIES
BEFORE CLOUDS RETURN DURING THURSDAY AS ISENTROPIC LIFT DEVELOPS
OVER THE SOUTHWESTERN PERIPHERY OF THE OFFSHORE HIGH.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 145 PM WEDNESDAY...SFC RIDGING...NOSED SSWWD INTO THE CWFA...
WILL LINGER THRU THURSDAY NIGHT. FORCING FOR ANY PCPN WILL BE IN THE
FORM OF WEAK UPGLIDE/UPSLOPE...RESULTING IN SCATTERED LIGHT
RAIN/SHOWER/DRIZZLE POSSIBILITIES...MAINLY ACRS THE MTNS/FTHLS.
MOUNTAIN MIN TEMPS SHOULD EXPERIENCE A NEGATIVE VALLEY TO RIDGETOP
LAPSE RATE...AND AT THIS JUNCTURE...WE ARE EXPECTING EVEN THE
COLDEST NC MTN VALLEYS TO REMAIN JUST ABOVE FREEZING. LLVL WAA FLOW
REGIME IS PROGGED TO LINGER ATOP WEAKENING SFC RIDGE ON FRIDAY.
SHORT RANGE MODELS CONTINUE TO ADVERTISE SPOTTY RESPONSE AND WOULD
EXPECT THE PROSPECT FOR ANYTHING MORE THAN FILTERED OR DIM SUNSHINE
DEVELOPMENT TO BE LOW. NONETHELESS...TEMPERATURES SHOULD MODERATE
SOME FROM THURSDAY/S CHILLY READINGS...WITH A MOS BLEND SUPPORTING
ABOUT A 5 DEG F BUMP. A DEEPER/QUICKENING WSW FLOW WILL DEVELOP ATOP
THE SE CONUS ON SATURDAY ERODING THE LINGERING COOL WEDGE AND
CONTRIBUTING TO TEMPERATURES WARMING TO 10 DEG F ABOVE CLIMO. A
FRONTAL BNDRY IS PROGGED TO MAKE A PUSH TOWARD THE MTNS LATE IN THE
DAY BUT SHOULD STALL WELL NW OF THE AREA. PLUME OF WEAK INSTABILITY
AHEAD OF THIS FEATURE COMBINED WITH TERRAIN LIFT COULD BE ENOUGH TO
TRIGGER A FEW MTN SHOWERS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 230 PM WEDNESDAY...MODELS HAVE CONVERGED ON THE TIMING OF A
COLD FROPA ON MONDAY...AS A LOW PRES SYSTEM TRACKS FROM THE SOUTHERN
PLAINS TO THE GREAT LAKES OVER THE WEEKEND. BEFORE THE FRONT
ARRIVES...PERSISTENT DEEP SWLY FLOW WILL CONTINUE ACRS THE FA. MOS
SEEMS OVERDONE ON POPS THRU SUNDAY NIGHT...AS THE ONLY FORCING FOR
PRECIP WILL BE UPSLOPE IN THE SW NC MTNS. I AM UNDERCUTTING THE
GUIDANCE ON POPS SATURDAY NIGHT THRU SUNDAY NIGHT.
THE LATEST MODEL CONSENSUS HAS THE FRONT CROSSING THE CWFA FROM WEST
TO EAST DURING THE DAY ON MONDAY. A FAIRLY GOOD MOISTURE PLUME WILL
ACCOMPANY THE FRONT WITH STRONG UPPER LEVEL DIVERGENCE. SO POPS ARE
RAMPED UP TO LIKELY IN THE MTNS AND HIGH-END CHC EAST. THIS WOULD BE
A MORE FAVORABLE TIME OF DAY FOR INSTBY. WITH THAT SAID...THE MODELS
ARE STILL MEAGER ON SBCAPE...WITH THE GFS AND ECMWF HAVING 100-200
J/KG AHEAD OF THE FRONT. SHEAR DOES LOOK GOOD THO...WITH SWLY 0-6KM
BULK SHEAR 50-60 KTS IN THE PIEDMONT AND EVEN GREATER TO THE WEST.
THE GFS FCST SNDG SHOWS SOME DIRECTIONAL SHEAR AS WELL WITH 0-3KM
HELICITY IN THE 150-250 M2/S2 RANGE. SO EVEN A LITTLE INSTBY COULD
BE ENUF FOR A HIGH-SHEAR/LOW-CAPE SEVERE EVENT. USING THE GFS CAPE
AS A GUIDE...DID ADD SOME MENTION OF THUNDER FOR MONDAY.
MONDAY NIGHT INTO TUESDAY...AS THE LOW WRAPS UP OVR THE EASTERN
GREAT LAKES...NWLY LLVL FLOW WILL USHER IN COLD AIR ACRS THE AREA.
GUIDANCE SEEMS TO INDICATE THAT THE COLD AIR WILL CHASE THE
MOISTURE...SUCH THAT VERY LITTLE IF ANY SNOW WILL FOLLOW BEHIND THE
FROPA. I GRADUALLY RAMP POPS DOWN INTO TUESDAY...WITH SNOW LEVELS
POSSIBLY FALLING TO 3500 FT BEFORE DAYBREAK TUESDAY. NO SIGNIFICANT
ACCUMS ARE EXPECTED. TUESDAY WILL BE COOLER WITH TEMPS NEAR OR
SLIGHTLY BELOW NORMAL. DRY HIGH PRES BUILDS IN FOR WEDNESDAY.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
AT KCLT... LEADING EDGE OF SURFACE FRONTAL ZONE HAS MOVED SOUTH OF
KCLT SO THE WIND WILL SETTLE INTO A NORTHEAST DIRECTION THAT WILL
CONTINUE THROUGH THE REMAINDER OF THE AFTERNOON. SPEED WILL REMAIN
AROUND 10 KT OR LOWER. FRONTAL CLOUDS WILL CONTINUE TO AFFECT THE
TERMINAL WITH CEILING GENERALLY 5-7 KT FT. A BAND OF LIGHT RAIN AND
SHOWERS WILL AFFECT THE AIRFIELD THROUGH 22Z. AN AREA OF CAPES NEAR
300 J/KG WILL EXIST TO THE SOUTH OF THE AIRFIELD... BUT CAPES IN THE
IMMEDIATE VICINITY APPEAR TOO LOW TO SUPPORT THUNDER. THUS... CHANCE
OF A THUNDERSTORM IS NOT IN THE TAF AT THIS TIME. DURING THE
OVERNIGHT PERIOD... WEAK ISENTROPIC LIFT ASSOCIATED WITH COLD AIR
DAMMING WILL PRODUCE CLOUD BASES NEAR 5K FT. BY 09Z A SCATTERED TO
BROKEN LAYER AROUND 2K FT IS POSSIBLE BUT VISIBILITY SHOULD REMAIN
UNRESTRICTED.
ELSEWHERE... SURFACE FRONT WILL MOVE SOUTH OF KGSP/KGMU/KAND DURING
LATE AFTERNOON AND THIS EVENING. CEILINGS WILL GENERALLY BE IN THE
5-7K FT RANGE EXCEPT SCATTERED CEILING 3-4K FT IN SHOWERS AND
ISOLATED THUNDERSTORMS. DRIER AIR SPREADING INTO AREA FROM THE
NORTHEAST WILL RESULT IN CLOUDS SCATTERING OUT AT KHKY AFT 00Z...
BUT A 5K FT CEILING WILL RETURN THURSDAY MORNING. EVEN THOUGH FRONT
WILL BE SOUTH OF AREA... FRONTAL CLOUD BAND WILL REMAIN OVER THE
FORECAST AREA AS A RELATIVELY SHORT COLD AIR DAMMING PATTERN
DEVELOPS. WINDS WILL BECOME NORTHEAST AT ALL TERMINALS EXCEPT KAVL
WHERE NORTH TO NORTHWEST WIND WITH GUSTS TO 20 KT WILL CONTINUE INTO
TONIGHT.
OUTLOOK... WIDELY SCATTERED SHOWERS WITH CEILING AND VISIBILITY
RESTRICTIONS POSSIBLE OVER THE MOUNTAINS FRIDAY AND SATURDAY.
STRATUS AND FOG COULD OCCUR BOTH DAYS DUE TO WEAKENING COLD AIR
DAMMING. COLD FRONT CROSSING THE AREA MONDAY WILL PRODUCE SCATTERED
SHOWERS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...LGL
SHORT TERM...CSH
LONG TERM...ARK
AVIATION...LGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
119 PM EST WED DEC 5 2012
.SYNOPSIS...
A COLD FRONT WILL DRIFT SOUTHEAST ACROSS THE AREA TODAY AND REACH
THE SOUTH CAROLINA COAST THIS EVENING. HIGH PRESSURE WILL RETURN
THURSDAY AND FRIDAY. EXPECT THIS HIGH TO BECOME CENTERED OFF THE
EAST COAST WHICH WILL RESULT IN A STRONG SOUTHERLY FLOW OF WARM AND
MOIST AIR OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 105 PM... EARLY AFTERNOON UPDATE CARRIES CHANCE POPS ACROSS NC
PIEDMONT AND SC UPSTATE AS SHOWERS ASSOCIATED WITH COLD FRONT
ADVANCE THROUGH THE AREA. CAPES ARE QUITE LOW... 100 TO 250 J/KG
ESPECIALLY ACROSS NORTHERN UPSTATE WHERE HIGHER DEWPOINTS ARE
COLLECTING IN FRONTAL CONVERGENCE ZONE. LIGHT RAIN OR SHOWERS SHOULD
BE THE PREDOMINANT FORM OF PRECIPITATION... BUT ISOLATED THUNDER
WILL BE MENTIONED TO ACCOUNT FOR MARGINALLY FAVORABLE AIR MASS.
AS OF 935 AM...RADAR SHOWING SHRA OVER THE NC PIEDMONT AND NE GA AND
NWRN UPSTATE AHEAD OF THE COLD FRONT SLOWLY MOVING ACROSS THE AREA.
EXPECT THE SHRA TO DIMINISH ACROSS THE NC PIEDMONT THIS MORNING
LEAVING ONLY SCT SHRA. THE SHRA OVER GA/SC WILL CONTINUE THRU THE
AFTERNOON AND MOVE EAST AND SOUTH ACROSS THAT AREA AS THE FRONT
SLOWLY SAGS SWD. WITH MOISTURE POOLING ALONG THE FRONT OVER THAT
AREA...DEW POINTS WILL REMAIN RELATIVELY HIGH FOR THIS TIME OF YEAR.
12Z RAOBS SHOW ELEVATED INSTABILITY OVER THE AREA WITH WEAK LAPSE
RATE INCREASE DUE TO COOLING MID LEVELS. HAVE RETAINED TSRA WORDING
ACROSS NE GA/UPSTATE IN LINE WITH THESE TRENDS. TEMPS WILL BE TRICKY
WITH THE FRONTAL MOVEMENT AND VERY WARM START TO THE DAY. UPDATED
HIGHS BASED ON CURRENT GUIDANCE WHICH DID MAKE SOME MINOR CHANGES.
AS OF 635 AM EST WEDNESDAY...LOCAL RADAR...SFC OBS AND IFLOWS
OBSERVATIONS SHOW THAT SHOWERS HAVE INCREASED OVER THE NC AND NE GA
MTNS THE PAST FEW HOURS. THIS IS IN LINE WITH THE FORECAST. SOME
LIGHTER SHOWERS ARE ALSO FALLING OVER THE FOOTHILLS AND
PIEDMONT...BUT THEY ARE LIGHTER. A MORE CONCENTRATED AREA OF RAIN
HAS DEVELOPED OVER NRN GA AND SHOULD MOVE INTO RABUN...HABERSHAM AND
OCONEE COUNTIES OVER THE NEXT COUPLE HOURS.
AS OF 435 AM EST WEDNESDAY...ADJUSTED MIN TEMPS UP A COUPLE DEGREES
BASED ON INCREASING CLOUD COVER. PATCHY LIGHT RAIN AND A FEW HEAVIER
SHOWERS ARE DEVELOPING OVER WRN NC AND ALONG THE TN LINE. THIS LINES
UP FAIRLY WELL WITH THE GRADUALLY INCREASING POP TREND IN THE GRIDS.
PREVIOUS DISCUSSION...
A STRONG TROUGH WILL MOVE ACROSS THE NEW ENGLAND STATES
TODAY...WHILE A CUT-OFF SRN STREAM LOW DRIFTS DOWN INTO THE NRN GULF
OF MEXICO. A SFC FRONT WILL STALL OVER THE MOUNTAINS THIS
MORNING...THOUGH HEIGHT RISES ACROSS THE MID-ATLANTIC STATES WILL
SEND THE THE FRONT SURGING SOUTHWARD A LITTLE LATER IN THE DAY. WEAK
H8 FRONTOGENESIS WILL ACCOMPANY THE BNDRY...THOUGH THE DEEP LAYER
FORCING LOOKS WEAK. LOW LEVEL CONVERGENCE WILL POOL MOISTURE AHEAD
OF THE FRONT AND MOST OF THE NUMERICAL MODELS DEVELOP ENOUGH
INSTABILITY OVER THE UPSTATE...SRN NC MTNS AND NE GA TO SUPPORT
SHOWERS AND EVEN A FEW TSTMS THIS AFTERNOON. THE NAM IS A LITTLE
FASTER THAN THE GFS...WHILE THE RUC IS A HAIR SLOWER THAN EITHER
MODEL. I HAVE EXTENDED THUNDER CHANCES UP ACROSS THE SRN NC MTNS AS
I DON/T SEE THE BNDRY MAKING IT THROUGH THESE AREAS UNTIL LATE AFTN.
IN FACT...THE FRONT WILL MAKE IT THROUGH CHARLOTTE AND THE NE
UPSTATE BEFORE THE CLEARS THE ESCARPMENT. CONVECTION IS EXPECTED TO
THEN SETTLE SOUTHWARD ACROSS THE UPSTATE AND NE GA. ATTM I DON/T
EXPECT ANYTHING SEVERE OWING TO THE MOIST MID-LEVELS AND WEAK LAPSE
RATES.
HIGH PRESSURE WILL CONTINUE TO RIDGE DOWN THE EAST SLOPES OF THE
APPALACHIANS TONIGHT. THE 1031 MB SFC HIGH CENTERS OVER PENNSYLVANIA
QUALIFIES AS A CLASSICAL COLD AIR DAMMING...AND IT WILL BRING A GOOD
INFLUX AND COOL AND DRY LOW LEVEL AIR INTO THE REGION. SKIES SHOULD
CLEAR OVERNIGHT ACROSS MUCH OF NORTH CAROLINA...AT LEAST NORTH OF A
LINE FROM CHARLOTTE TO ASHEVILLE...WHILE SKIES REMAIN CLOUDY OVER
THE UPSTATE AND NE GA ATOP THE DAMMING AIRMASS. THE MOISTURE LOOKS
SHALLOW AND PCPN CHANCES WILL BE LOW AND CONFINED TO THE SRN MOST
ZONES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 245 AM WEDNESDAY...SHORT RANGE MODELS BEGIN THE SHORT RANGE
PERIOD...12Z THURS...IN GOOD AGREEMENT WITH THE POSITION OF THE BACK
DOOR COLD FRONT ACROSS THE UPPER SAVANNAH RIVER VALLEY AND SFC HIGH
PRESSURE CENTERED OVER THE MID ATLANTIC AND NEW ENGLAND STATES. AT
H5...A TROF IS EXPECTED TO PIVOT OVER THE NRN GULF...SUPPORTING THE
FORMATION OF A WEAK LOW NEAR THE MISSISSIPPI DELTA DURING THE
DAYLIGHT HOURS. AT 295K...WEAK ISENTROPIC LIFT IS EXPECTED TO
CONTINUE OVER NE GA AND THE WESTERN CAROLINAS THROUGH THURSDAY.
FORECAST SOUNDINGS INDICATE THAT THE CLOUD LAYER MAY RANGE BETWEEN
5-10 KFT...WITH LLVL NE FLOW. LLVL LIFT AND THICK MOISTURE MAY YIELD
PATCHES OF -RA TO SPRINKLES...BUT MEASURABLE QPF SEEMS UNLIKELY.
HOWEVER...GIVEN THE THICK CLOUD COVER FROM SUNRISE TO SUNSET AND
PERSISTENT NE FLOW...HIGH TEMPERATURES SHOULD VERIFY FAIRLY UNIFORM
ACROSS THE CWA ON THURSDAY. I WILL POPULATE TEMPS FROM THE NAM 2M
TEMPS...YIELDING HIGH TEMPERATURE FORECAST FROM THE MID 50S ALONG
AND EAST OF I-85 TO NEAR 50 ALONG AND NORTH OF I-40.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...THE CENTER OF HIGH PRESSURE SHOULD
SLIDE OVER THE WESTERN ATLANTIC AS LOW PRESSURE DEVELOPS OVER THE
CENTRAL PLAIN AND MID MISSISSIPPI RIVER VALLEY. FORECAST SOUNDINGS
INDICATE THAT CLOUD COVER WILL REMAIN PLENTIFUL ACROSS THE CWA
THROUGH THE PERIOD. LLVL LIFT AND SYNOPTIC SCALE FORCING WILL REMAIN
VERY WEAK...SUPPORTING MAINLY SCHC POPS ACROSS THE MTNS AND
FOOTHILLS. TEMPERATURES WILL GRADUALLY MODERATE THROUGH THE
PERIOD...REMAINING WELL ABOVE NORMAL AT NIGHT AND NEAR NORMAL FOR
FRIDAY HIGHS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 240 AM WEDNESDAY...THE MEDIUM RANGE WILL BE A PERIOD OF TIME
UNDER THE INFLUENCE OF A SOUTHERLY FLOW PRIOR TO THE ARRIVAL OF A
COLD FRONT IN THE FIRST HALF OF THE WEEK. HIGH PRESSURE WILL BE
CENTERED NEAR BERMUDA WITH A SOUTHERLY FLOW WHICH WILL CONTINUE
THROUGH THE WEEKEND AND TO START THE WEEK AHEAD OF THE FRONT. ALL
MODELS AGREE ON THE GENERAL WEEKEND SCENARIO WITH THE WARMTH AND
MOISTURE ADVECTION AND SLIGHT TO LOW CHANCE POPS FROM NE GA TO
ACROSS THE WESTERN CAROLINAS.
THE GFS MODEL IS MOST PROGRESSIVE WITH THE FRONT MOVING EAST OF OUR
AREA MONDAY EVENING. SOME CAPE VALUES OF AROUND 20 ON GFS SATURDAY
AFTERNOON IN THE NC MTNS THEN RISE TO AROUND 160 OVER THE SMOKIES
SUNDAY AFTERNOON. IT ALL COMES TOGETHER ON THE GFS MONDAY AFTERNOON
WITH CAPES OF AROUND 160 FROM NE GA TO THE NC MTNS AND 850MB WIND 40
TO 50 KTS AND 700MB WIND 55 TO 65 KTS.
THE LATEST ECMWF WHICH JUST ARRIVED IS CLOSER TO THE GFS NOW IN
TIMING AND HAS THE FRONT EAST OF OUR AREA EARLY TUESDAY MORNING.
EARLIER RUN HAD THE FRONT ARRIVING EARLY TUESDAY AFTERNOON. WIND
SPEEDS ARE COMPARABLE TO THE GFS AND NOW SINCE THE ECMWF FRONT
ARRIVES EARLIER THE CAPES ARE HIGHER AS WELL. ECMWF HAS CAPES OF
400 TO 600 MONDAY AFTERNOON ALONG THE I-85 CORRIDOR. SINCE BOTH ARE
IN BETTER AGREEMENT...WILL INCREASE POPS LATE MONDAY AND THEN
DECREASE POPS TUESDAY AS THE FRONT SHOULD BE OUT OF THE AREA TO
EAST.
TEMPERATURES WILL BE 10 OR MORE DEGREES ABOVE NORMAL AHEAD OF THE
FRONT AND THEN STARTING A COOLING TREND BEHIND THE FRONT ON DAY 7
TUESDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AT KCLT... LEADING EDGE OF SURFACE FRONTAL ZONE HAS MOVED SOUTH OF
KCLT SO THE WIND WILL GRADUALLY SHIFT FROM NORTHWEST TO NORTHEAST
THROUGH THE REMAINDER OF THE AFTERNOON. SPEED WILL REMAIN AROUND 10
KT OR LOWER. FRONTAL CLOUDS WILL CONTINUE TO AFFECT THE TERMINAL
WITH CEILING GENERALLY 5-7 KT FT. SHOWERS THAT WERE CONSOLIDATING
WEST OF KCLT... OVER THE FOOTHILLS... COULD AFFECT THE AIRFIELD BY
20Z OR SO. AN AMENDMENT WILL BE ISSUED IF THEY HOLD TOGETHER. DURING
THE OVERNIGHT PERIOD... WEAK ISENTROPIC LIFT ASSOCIATED WITH COLD
AIR DAMMING WILL PRODUCE CLOUD BASES NEAR 5K FT. BY 09Z A SCATTERED
TO BROKEN LAYER AROUND 2K FT IS POSSIBLE BUT VISIBILITY SHOULD
REMAIN UNRESTRICTED.
ELSEWHERE... SURFACE FRONT WILL MOVE SOUTH OF KGSP/KGMU/KAND DURING
MID TO LATE AFTERNOON. CEILINGS WILL GENERALLY BE IN THE 5-7K FT
RANGE EXCEPT SCATTERED CEILING 3-4K FT IN SHOWERS. DRIER AIR
SPREADING INTO AREA FROM THE NORTHEAST WILL RESULT IN CLOUDS
SCATTERING OUT AT KHKY AFT 00Z... BUT EVEN THEIR CEILING NEAR 5K FT
WILL RETURN THURSDAY MORNING. EVEN THOUGH FRONT WILL BE SOUTH OF
AREA... FRONTAL CLOUD BAND WILL REMAIN OVER AREA AS CA RELATIVELY
SHORT COLD AIR DAMMING PATTERN DEVELOPS. FOLLOWING FRONTAL
PASSAGE... WINDS WILL BECOME NORTHEAST AT ALL TERMINALS EXCEPT KAVL
WHERE NORTH TO NORTHWEST WIND GUSTY TO 20 KT AT TIMES WILL CONTINUE
INTO TONIGHT.
OUTLOOK...COLD AIR DAMMING MAY RESTRICT CIGS WEDNESDAY NIGHT INTO
FRIDAY. MORNING RESTRICTIONS IN FOG AND STRATUS ARE POSSIBLE EARLY
SATURDAY AND SUNDAY WITH FAIR CONDITIONS EXPECTED DURING THE
AFTERNOONS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...LGL
SHORT TERM...NED
LONG TERM...DEO
AVIATION...LGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
943 AM EST WED DEC 5 2012
.SYNOPSIS...
A COLD FRONT WILL DRIFT SOUTHEAST ACROSS THE AREA TODAY AND REACH
THE SOUTH CAROLINA COAST THIS EVENING. HIGH PRESSURE WILL RETURN
THURSDAY AND FRIDAY. EXPECT THIS HIGH TO BECOME CENTERED OFF THE
EAST COAST WHICH WILL RESULT IN A STRONG SOUTHERLY FLOW OF WARM AND
MOIST AIR OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 935 AM...RADAR SHOWING SHRA OVER THE NC PIEDMONT AND NE GA AND
NWRN UPSTATE AHEAD OF THE COLD FRONT SLOWLY MOVING ACROSS THE AREA.
EXPECT THE SHRA TO DIMINISH ACROSS THE NC PIEDMONT THIS MORNING
LEAVING ONLY SCT SHRA. THE SHRA OVER GA/SC WILL CONTINUE THRU THE
AFTERNOON AND MOVE EAST AND SOUTH ACROSS THAT AREA AS THE FRONT
SLOWLY SAGS SWD. WITH MOISTURE POOLING ALONG THE FRONT OVER THAT
AREA...DEW POINTS WILL REMAIN RELATIVELY HIGH FOR THIS TIME OF YEAR.
12Z RAOBS SHOW ELEVATED INSTABILITY OVER THE AREA WITH WEAK LAPSE
RATE INCREASE DUE TO COOLING MID LEVELS. HAVE RETAINED TSRA WORDING
ACROSS NE GA/UPSTATE IN LINE WITH THESE TRENDS. TEMPS WILL BE TRICKY
WITH THE FRONTAL MOVEMENT AND VERY WARM START TO THE DAY. UPDATED
HIGHS BASED ON CURRENT GUIDANCE WHICH DID MAKE SOME MINOR CHANGES.
AS OF 635 AM EST WEDNESDAY...LOCAL RADAR...SFC OBS AND IFLOWS
OBSERVATIONS SHOW THAT SHOWERS HAVE INCREASED OVER THE NC AND NE GA
MTNS THE PAST FEW HOURS. THIS IS IN LINE WITH THE FORECAST. SOME
LIGHTER SHOWERS ARE ALSO FALLING OVER THE FOOTHILLS AND
PIEDMONT...BUT THEY ARE LIGHTER. A MORE CONCENTRATED AREA OF RAIN
HAS DEVELOPED OVER NRN GA AND SHOULD MOVE INTO RABUN...HABERSHAM AND
OCONEE COUNTIES OVER THE NEXT COUPLE HOURS.
AS OF 435 AM EST WEDNESDAY...ADJUSTED MIN TEMPS UP A COUPLE DEGREES
BASED ON INCREASING CLOUD COVER. PATCHY LIGHT RAIN AND A FEW HEAVIER
SHOWERS ARE DEVELOPING OVER WRN NC AND ALONG THE TN LINE. THIS LINES
UP FAIRLY WELL WITH THE GRADUALLY INCREASING POP TREND IN THE GRIDS.
PREVIOUS DISCUSSION...
A STRONG TROUGH WILL MOVE ACROSS THE NEW ENGLAND STATES
TODAY...WHILE A CUT-OFF SRN STREAM LOW DRIFTS DOWN INTO THE NRN GULF
OF MEXICO. A SFC FRONT WILL STALL OVER THE MOUNTAINS THIS
MORNING...THOUGH HEIGHT RISES ACROSS THE MID-ATLANTIC STATES WILL
SEND THE THE FRONT SURGING SOUTHWARD A LITTLE LATER IN THE DAY. WEAK
H8 FRONTOGENESIS WILL ACCOMPANY THE BNDRY...THOUGH THE DEEP LAYER
FORCING LOOKS WEAK. LOW LEVEL CONVERGENCE WILL POOL MOISTURE AHEAD
OF THE FRONT AND MOST OF THE NUMERICAL MODELS DEVELOP ENOUGH
INSTABILITY OVER THE UPSTATE...SRN NC MTNS AND NE GA TO SUPPORT
SHOWERS AND EVEN A FEW TSTMS THIS AFTERNOON. THE NAM IS A LITTLE
FASTER THAN THE GFS...WHILE THE RUC IS A HAIR SLOWER THAN EITHER
MODEL. I HAVE EXTENDED THUNDER CHANCES UP ACROSS THE SRN NC MTNS AS
I DON/T SEE THE BNDRY MAKING IT THROUGH THESE AREAS UNTIL LATE AFTN.
IN FACT...THE FRONT WILL MAKE IT THROUGH CHARLOTTE AND THE NE
UPSTATE BEFORE THE CLEARS THE ESCARPMENT. CONVECTION IS EXPECTED TO
THEN SETTLE SOUTHWARD ACROSS THE UPSTATE AND NE GA. ATTM I DON/T
EXPECT ANYTHING SEVERE OWING TO THE MOIST MID-LEVELS AND WEAK LAPSE
RATES.
HIGH PRESSURE WILL CONTINUE TO RIDGE DOWN THE EAST SLOPES OF THE
APPALACHIANS TONIGHT. THE 1031 MB SFC HIGH CENTERS OVER PENNSYLVANIA
QUALIFIES AS A CLASSICAL COLD AIR DAMMING...AND IT WILL BRING A GOOD
INFLUX AND COOL AND DRY LOW LEVEL AIR INTO THE REGION. SKIES SHOULD
CLEAR OVERNIGHT ACROSS MUCH OF NORTH CAROLINA...AT LEAST NORTH OF A
LINE FROM CHARLOTTE TO ASHEVILLE...WHILE SKIES REMAIN CLOUDY OVER
THE UPSTATE AND NE GA ATOP THE DAMMING AIRMASS. THE MOISTURE LOOKS
SHALLOW AND PCPN CHANCES WILL BE LOW AND CONFINED TO THE SRN MOST
ZONES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 245 AM WEDNESDAY...SHORT RANGE MODELS BEGIN THE SHORT RANGE
PERIOD...12Z THURS...IN GOOD AGREEMENT WITH THE POSITION OF THE BACK
DOOR COLD FRONT ACROSS THE UPPER SAVANNAH RIVER VALLEY AND SFC HIGH
PRESSURE CENTERED OVER THE MID ATLANTIC AND NEW ENGLAND STATES. AT
H5...A TROF IS EXPECTED TO PIVOT OVER THE NRN GULF...SUPPORTING THE
FORMATION OF A WEAK LOW NEAR THE MISSISSIPPI DELTA DURING THE
DAYLIGHT HOURS. AT 295K...WEAK ISENTROPIC LIFT IS EXPECTED TO
CONTINUE OVER NE GA AND THE WESTERN CAROLINAS THROUGH THURSDAY.
FORECAST SOUNDINGS INDICATE THAT THE CLOUD LAYER MAY RANGE BETWEEN
5-10 KFT...WITH LLVL NE FLOW. LLVL LIFT AND THICK MOISTURE MAY YIELD
PATCHES OF -RA TO SPRINKLES...BUT MEASURABLE QPF SEEMS UNLIKELY.
HOWEVER...GIVEN THE THICK CLOUD COVER FROM SUNRISE TO SUNSET AND
PERSISTENT NE FLOW...HIGH TEMPERATURES SHOULD VERIFY FAIRLY UNIFORM
ACROSS THE CWA ON THURSDAY. I WILL POPULATE TEMPS FROM THE NAM 2M
TEMPS...YIELDING HIGH TEMPERATURE FORECAST FROM THE MID 50S ALONG
AND EAST OF I-85 TO NEAR 50 ALONG AND NORTH OF I-40.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...THE CENTER OF HIGH PRESSURE SHOULD
SLIDE OVER THE WESTERN ATLANTIC AS LOW PRESSURE DEVELOPS OVER THE
CENTRAL PLAIN AND MID MISSISSIPPI RIVER VALLEY. FORECAST SOUNDINGS
INDICATE THAT CLOUD COVER WILL REMAIN PLENTIFUL ACROSS THE CWA
THROUGH THE PERIOD. LLVL LIFT AND SYNOPTIC SCALE FORCING WILL REMAIN
VERY WEAK...SUPPORTING MAINLY SCHC POPS ACROSS THE MTNS AND
FOOTHILLS. TEMPERATURES WILL GRADUALLY MODERATE THROUGH THE
PERIOD...REMAINING WELL ABOVE NORMAL AT NIGHT AND NEAR NORMAL FOR
FRIDAY HIGHS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 240 AM WEDNESDAY...THE MEDIUM RANGE WILL BE A PERIOD OF TIME
UNDER THE INFLUENCE OF A SOUTHERLY FLOW PRIOR TO THE ARRIVAL OF A
COLD FRONT IN THE FIRST HALF OF THE WEEK. HIGH PRESSURE WILL BE
CENTERED NEAR BERMUDA WITH A SOUTHERLY FLOW WHICH WILL CONTINUE
THROUGH THE WEEKEND AND TO START THE WEEK AHEAD OF THE FRONT. ALL
MODELS AGREE ON THE GENERAL WEEKEND SCENARIO WITH THE WARMTH AND
MOISTURE ADVECTION AND SLIGHT TO LOW CHANCE POPS FROM NE GA TO
ACROSS THE WESTERN CAROLINAS.
THE GFS MODEL IS MOST PROGRESSIVE WITH THE FRONT MOVING EAST OF OUR
AREA MONDAY EVENING. SOME CAPE VALUES OF AROUND 20 ON GFS SATURDAY
AFTERNOON IN THE NC MTNS THEN RISE TO AROUND 160 OVER THE SMOKIES
SUNDAY AFTERNOON. IT ALL COMES TOGETHER ON THE GFS MONDAY AFTERNOON
WITH CAPES OF AROUND 160 FROM NE GA TO THE NC MTNS AND 850MB WIND 40
TO 50 KTS AND 700MB WIND 55 TO 65 KTS.
THE LATEST ECMWF WHICH JUST ARRIVED IS CLOSER TO THE GFS NOW IN
TIMING AND HAS THE FRONT EAST OF OUR AREA EARLY TUESDAY MORNING.
EARLIER RUN HAD THE FRONT ARRIVING EARLY TUESDAY AFTERNOON. WIND
SPEEDS ARE COMPARABLE TO THE GFS AND NOW SINCE THE ECMWF FRONT
ARRIVES EARLIER THE CAPES ARE HIGHER AS WELL. ECMWF HAS CAPES OF
400 TO 600 MONDAY AFTERNOON ALONG THE I-85 CORRIDOR. SINCE BOTH ARE
IN BETTER AGREEMENT...WILL INCREASE POPS LATE MONDAY AND THEN
DECREASE POPS TUESDAY AS THE FRONT SHOULD BE OUT OF THE AREA TO
EAST.
TEMPERATURES WILL BE 10 OR MORE DEGREES ABOVE NORMAL AHEAD OF THE
FRONT AND THEN STARTING A COOLING TREND BEHIND THE FRONT ON DAY 7
TUESDAY.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...MAIN AREA OF SHRA SHUD REMAIN NORTH OF THE AIRFIELD THIS
MORNING. CANNOT RULE OUT AN SHRA AS THE FRONT MOVES THRU...BUT CHC
OF ANY VSBY RESTRICTIONS WITH PRECIP IS VERY LOW. AS THE COLD FRONT
MOVES IN FROM THE NORTH DURING THE EARLY AFTERNOON...WINDS TURN FROM
SOUTHWEST TO NORTHEAST AROUND 18 UTC. LATEST GUIDANCE SHOWS CIGS
WITH THE FRONT TO REMAIN VFR...BUT COULD BE LOW VFR CAUSING SOME
RESTRICTIONS. CIGS LIFTING ABOUT TO AROUND 7-8KFT DURING THE LATE
EVENING HOURS. WINDS WILL AVERAGE AROUND 8KTS BEHIND THE FRONT.
SHOWERS AND TSTMS WILL INCREASE ALONG THE FRONT THIS AFTN...BUT THAT
SHOULD BE AFTER IT MOVES SOUTH OF THE AIRFIELD.
ELSEWHERE...SHOWERS CONTINUE OVER NORTHERN GA AND THE NWRN UPSTATE
THIS MORNING. CIGS WILL LOWER SOME THIS MORNING...BUT PROBABLY NOT
LOWER THAN ABOUT 5KFT. SCT TSTMS WILL DEVELOP IN THE VICINITY OF THE
UPSTATE TAF SITES BY MID AFTN WITH CIGS FALLING TO 3-4KFT. MEANWHILE
DRIER AIR WILL WORK INTO KHKY WITH GRADUALLY RISING CIGS. BY EARLY
EVENING THE STORMS WILL MOVE SOUTH OF ALL THE AIRFIELDS. DRIER LOW
LEVEL AIR WILL BRING CIGS UP TO AROUND 5KFT FEET AT ALL SOUTHERN TAF
SITES THROUGH THE NIGHT.
OUTLOOK...COLD AIR DAMMING MAY RESTRICT CIGS WEDNESDAY NIGHT INTO
FRIDAY. MORNING RESTRICTIONS IN FOG AND STRATUS ARE POSSIBLE EARLY
SATURDAY AND SUNDAY WITH FAIR CONDITIONS EXPECTED DURING THE
AFTERNOONS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...MCAVOY/RWH
SHORT TERM...NED
LONG TERM...DEO
AVIATION...MCAVOY/RWH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
638 AM EST WED DEC 5 2012
.SYNOPSIS...
A COLD FRONT WILL DRIFT SOUTHEAST ACROSS THE AREA TODAY AND REACH
THE SOUTH CAROLINA COAST THIS EVENING. HIGH PRESSURE WILL RETURN
THURSDAY AND FRIDAY. EXPECT THIS HIGH TO BECOME CENTERED OFF THE
EAST COAST WHICH WILL RESULT IN A STRONG SOUTHERLY FLOW OF WARM AND
MOIST AIR OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 635 AM EST WEDNESDAY...LOCAL RADAR...SFC OBS AND IFLOWS
OBSERVATIONS SHOW THAT SHOWERS HAVE INCREASED OVER THE NC AND NE GA
MTNS THE PAST FEW HOURS. THIS IS IN LINE WITH THE FORECAST. SOME
LIGHTER SHOWERS ARE ALSO FALLING OVER THE FOOTHILLS AND
PIEDMONT...BUT THEY ARE LIGHTER. A MORE CONCENTRATED AREA OF RAIN
HAS DEVELOPED OVER NRN GA AND SHOULD MOVE INTO RABUN...HABERSHAM AND
OCONEE COUNTIES OVER THE NEXT COUPLE HOURS.
AS OF 435 AM EST WEDNESDAY...ADJUSTED MIN TEMPS UP A COUPLE DEGREES
BASED ON INCREASING CLOUD COVER. PATCHY LIGHT RAIN AND A FEW HEAVIER
SHOWERS ARE DEVELOPING OVER WRN NC AND ALONG THE TN LINE. THIS LINES
UP FAIRLY WELL WITH THE GRADUALLY INCREASING POP TREND IN THE GRIDS.
PREVIOUS DISCUSSION...
A STRONG TROUGH WILL MOVE ACROSS THE NEW ENGLAND STATES
TODAY...WHILE A CUT-OFF SRN STREAM LOW DRIFTS DOWN INTO THE NRN GULF
OF MEXICO. A SFC FRONT WILL STALL OVER THE MOUNTAINS THIS
MORNING...THOUGH HEIGHT RISES ACROSS THE MID-ATLANTIC STATES WILL
SEND THE THE FRONT SURGING SOUTHWARD A LITTLE LATER IN THE DAY. WEAK
H8 FRONTOGENESIS WILL ACCOMPANY THE BNDRY...THOUGH THE DEEP LAYER
FORCING LOOKS WEAK. LOW LEVEL CONVERGENCE WILL POOL MOISTURE AHEAD
OF THE FRONT AND MOST OF THE NUMERICAL MODELS DEVELOP ENOUGH
INSTABILITY OVER THE UPSTATE...SRN NC MTNS AND NE GA TO SUPPORT
SHOWERS AND EVEN A FEW TSTMS THIS AFTERNOON. THE NAM IS A LITTLE
FASTER THAN THE GFS...WHILE THE RUC IS A HAIR SLOWER THAN EITHER
MODEL. I HAVE EXTENDED THUNDER CHANCES UP ACROSS THE SRN NC MTNS AS
I DON/T SEE THE BNDRY MAKING IT THROUGH THESE AREAS UNTIL LATE AFTN.
IN FACT...THE FRONT WILL MAKE IT THROUGH CHARLOTTE AND THE NE
UPSTATE BEFORE THE CLEARS THE ESCARPMENT. CONVECTION IS EXPECTED TO
THEN SETTLE SOUTHWARD ACROSS THE UPSTATE AND NE GA. ATTM I DON/T
EXPECT ANYTHING SEVERE OWING TO THE MOIST MID-LEVELS AND WEAK LAPSE
RATES.
HIGH PRESSURE WILL CONTINUE TO RIDGE DOWN THE EAST SLOPES OF THE
APPALACHIANS TONIGHT. THE 1031 MB SFC HIGH CENTERS OVER PENNSYLVANIA
QUALIFIES AS A CLASSICAL COLD AIR DAMMING...AND IT WILL BRING A GOOD
INFLUX AND COOL AND DRY LOW LEVEL AIR INTO THE REGION. SKIES SHOULD
CLEAR OVERNIGHT ACROSS MUCH OF NORTH CAROLINA...AT LEAST NORTH OF A
LINE FROM CHARLOTTE TO ASHEVILLE...WHILE SKIES REMAIN CLOUDY OVER
THE UPSTATE AND NE GA ATOP THE DAMMING AIRMASS. THE MOISTURE LOOKS
SHALLOW AND PCPN CHANCES WILL BE LOW AND CONFINED TO THE SRN MOST
ZONES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 245 AM WEDNESDAY...SHORT RANGE MODELS BEGIN THE SHORT RANGE
PERIOD...12Z THURS...IN GOOD AGREEMENT WITH THE POSITION OF THE BACK
DOOR COLD FRONT ACROSS THE UPPER SAVANNAH RIVER VALLEY AND SFC HIGH
PRESSURE CENTERED OVER THE MID ATLANTIC AND NEW ENGLAND STATES. AT
H5...A TROF IS EXPECTED TO PIVOT OVER THE NRN GULF...SUPPORTING THE
FORMATION OF A WEAK LOW NEAR THE MISSISSIPPI DELTA DURING THE
DAYLIGHT HOURS. AT 295K...WEAK ISENTROPIC LIFT IS EXPECTED TO
CONTINUE OVER NE GA AND THE WESTERN CAROLINAS THROUGH THURSDAY.
FORECAST SOUNDINGS INDICATE THAT THE CLOUD LAYER MAY RANGE BETWEEN
5-10 KFT...WITH LLVL NE FLOW. LLVL LIFT AND THICK MOISTURE MAY YIELD
PATCHES OF -RA TO SPRINKLES...BUT MEASURABLE QPF SEEMS UNLIKELY.
HOWEVER...GIVEN THE THICK CLOUD COVER FROM SUNRISE TO SUNSET AND
PERSISTENT NE FLOW...HIGH TEMPERATURES SHOULD VERIFY FAIRLY UNIFORM
ACROSS THE CWA ON THURSDAY. I WILL POPULATE TEMPS FROM THE NAM 2M
TEMPS...YIELDING HIGH TEMPERATURE FORECAST FROM THE MID 50S ALONG
AND EAST OF I-85 TO NEAR 50 ALONG AND NORTH OF I-40.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...THE CENTER OF HIGH PRESSURE SHOULD
SLIDE OVER THE WESTERN ATLANTIC AS LOW PRESSURE DEVELOPS OVER THE
CENTRAL PLAIN AND MID MISSISSIPPI RIVER VALLEY. FORECAST SOUNDINGS
INDICATE THAT CLOUD COVER WILL REMAIN PLENTIFUL ACROSS THE CWA
THROUGH THE PERIOD. LLVL LIFT AND SYNOPTIC SCALE FORCING WILL REMAIN
VERY WEAK...SUPPORTING MAINLY SCHC POPS ACROSS THE MTNS AND
FOOTHILLS. TEMPERATURES WILL GRADUALLY MODERATE THROUGH THE
PERIOD...REMAINING WELL ABOVE NORMAL AT NIGHT AND NEAR NORMAL FOR
FRIDAY HIGHS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 240 AM WEDNESDAY...THE MEDIUM RANGE WILL BE A PERIOD OF TIME
UNDER THE INFLUENCE OF A SOUTHERLY FLOW PRIOR TO THE ARRIVAL OF A
COLD FRONT IN THE FIRST HALF OF THE WEEK. HIGH PRESSURE WILL BE
CENTERED NEAR BERMUDA WITH A SOUTHERLY FLOW WHICH WILL CONTINUE
THROUGH THE WEEKEND AND TO START THE WEEK AHEAD OF THE FRONT. ALL
MODELS AGREE ON THE GENERAL WEEKEND SCENARIO WITH THE WARMTH AND
MOISTURE ADVECTION AND SLIGHT TO LOW CHANCE POPS FROM NE GA TO
ACROSS THE WESTERN CAROLINAS.
THE GFS MODEL IS MOST PROGRESSIVE WITH THE FRONT MOVING EAST OF OUR
AREA MONDAY EVENING. SOME CAPE VALUES OF AROUND 20 ON GFS SATURDAY
AFTERNOON IN THE NC MTNS THEN RISE TO AROUND 160 OVER THE SMOKIES
SUNDAY AFTERNOON. IT ALL COMES TOGETHER ON THE GFS MONDAY AFTERNOON
WITH CAPES OF AROUND 160 FROM NE GA TO THE NC MTNS AND 850MB WIND 40
TO 50 KTS AND 700MB WIND 55 TO 65 KTS.
THE LATEST ECMWF WHICH JUST ARRIVED IS CLOSER TO THE GFS NOW IN
TIMING AND HAS THE FRONT EAST OF OUR AREA EARLY TUESDAY MORNING.
EARLIER RUN HAD THE FRONT ARRIVING EARLY TUESDAY AFTERNOON. WIND
SPEEDS ARE COMPARABLE TO THE GFS AND NOW SINCE THE ECMWF FRONT
ARRIVES EARLIER THE CAPES ARE HIGHER AS WELL. ECMWF HAS CAPES OF
400 TO 600 MONDAY AFTERNOON ALONG THE I-85 CORRIDOR. SINCE BOTH ARE
IN BETTER AGREEMENT...WILL INCREASE POPS LATE MONDAY AND THEN
DECREASE POPS TUESDAY AS THE FRONT SHOULD BE OUT OF THE AREA TO
EAST.
TEMPERATURES WILL BE 10 OR MORE DEGREES ABOVE NORMAL AHEAD OF THE
FRONT AND THEN STARTING A COOLING TREND BEHIND THE FRONT ON DAY 7
TUESDAY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...A CIG UP AROUND 10KFT SHOULD LOWER TO 5-6KFT OVER THE NEXT
FEW HOURS. A FEW LIGHT SHOWERS WILL PERSIST AROUND THE AIRFIELD THIS
MORNING...THOUGH FOR NOW I THINK VCSH CAN HANDLE IT. A COLD FRONT
WILL MOVE IN FROM THE NORTH DURING THE EARLY AFTERNOON...TURNING
WINDS FROM SOUTHWEST TO NORTHEAST AROUND 18 UTC. CIGS WITH THE FRONT
ARE EXPECTED TO DROP INTO THE MVFR RANGE FOR A FEW HOURS...WITH CIGS
LIFTING ABOUT TO AROUND 7-8KFT DURING THE LATE EVENING HOURS. WINDS
WILL AVERAGE AROUND 8KTS BEHIND THE FRONT. SHOWERS AND TSTMS WILL
INCREASE ALONG THE FRONT THIS AFTN...BUT THAT SHOULD BE AFTER IT
MOVES SOUTH OF THE AIRFIELD.
ELSEWHERE...SHOWERS HAVE BEEN GRADUALLY INCREASING OVER THE
MOUNTAINS AND NORTHERN GA THIS MORNING. PREVAILING SHRA HAVE BEEN
ADDED TO KAVL WITH VCSH AT THE OTHER AIRFIELDS. CIGS WILL LOWER SOME
THIS MORNING...BUT PROBABLY NOT LOWER THAN ABOUT 5KFT. SCT TSTMS
WILL DEVELOP IN THE VICINITY OF THE UPSTATE TAF SITES BY MID AFTN
WITH CIGS FALLING TO 3-4KFT. MEANWHILE DRIER AIR WILL WORK INTO KHKY
WITH GRADUALLY RISING CIGS. BY EARLY EVENING THE STORMS WILL MOVE
SOUTH OF ALL THE AIRFIELDS. DRIER LOW LEVEL AIR WILL BRING CIGS UP
TO AROUND 5KFT FEET AT ALL SOUTHERN TAF SITES THROUGH THE NIGHT.
OUTLOOK...COLD AIR DAMMING MAY RESTRICT CIGS WEDNESDAY NIGHT INTO
FRIDAY. MORNING RESTRICTIONS IN FOG AND STRATUS ARE POSSIBLE EARLY
SATURDAY AND SUNDAY WITH FAIR CONDITIONS EXPECTED DURING THE
AFTERNOONS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...MCAVOY
SHORT TERM...NED
LONG TERM...DEO
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
443 AM EST WED DEC 5 2012
.SYNOPSIS...
A COLD FRONT WILL DRIFT SOUTHEAST ACROSS THE AREA TODAY AND REACH
THE SOUTH CAROLINA COAST THIS EVENING. HIGH PRESSURE WILL RETURN
THURSDAY AND FRIDAY. EXPECT THIS HIGH TO BECOME CENTERED OFF THE
EAST COAST WHICH WILL RESULT IN A STRONG SOUTHERLY FLOW OF WARM AND
MOIST AIR OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 435 AM EST WEDNESDAY...ADJUSTED MIN TEMPS UP A COUPLE DEGREES
BASED ON INCREASING CLOUD COVER. PATCHY LIGHT RAIN AND A FEW HEAVIER
SHOWERS ARE DEVELOPING OVER WRN NC AND ALONG THE TN LINE. THIS LINES
UP FAIRLY WELL WITH THE GRADUALLY INCREASING POP TREND IN THE GRIDS.
PREVIOUS DISCUSSION...
A STRONG TROUGH WILL MOVE ACROSS THE NEW ENGLAND STATES
TODAY...WHILE A CUT-OFF SRN STREAM LOW DRIFTS DOWN INTO THE NRN GULF
OF MEXICO. A SFC FRONT WILL STALL OVER THE MOUNTAINS THIS
MORNING...THOUGH HEIGHT RISES ACROSS THE MID-ATLANTIC STATES WILL
SEND THE THE FRONT SURGING SOUTHWARD A LITTLE LATER IN THE DAY. WEAK
H8 FRONTOGENESIS WILL ACCOMPANY THE BNDRY...THOUGH THE DEEP LAYER
FORCING LOOKS WEAK. LOW LEVEL CONVERGENCE WILL POOL MOISTURE AHEAD
OF THE FRONT AND MOST OF THE NUMERICAL MODELS DEVELOP ENOUGH
INSTABILITY OVER THE UPSTATE...SRN NC MTNS AND NE GA TO SUPPORT
SHOWERS AND EVEN A FEW TSTMS THIS AFTERNOON. THE NAM IS A LITTLE
FASTER THAN THE GFS...WHILE THE RUC IS A HAIR SLOWER THAN EITHER
MODEL. I HAVE EXTENDED THUNDER CHANCES UP ACROSS THE SRN NC MTNS AS
I DON/T SEE THE BNDRY MAKING IT THROUGH THESE AREAS UNTIL LATE AFTN.
IN FACT...THE FRONT WILL MAKE IT THROUGH CHARLOTTE AND THE NE
UPSTATE BEFORE THE CLEARS THE ESCARPMENT. CONVECTION IS EXPECTED TO
THEN SETTLE SOUTHWARD ACROSS THE UPSTATE AND NE GA. ATTM I DON/T
EXPECT ANYTHING SEVERE OWING TO THE MOIST MID-LEVELS AND WEAK LAPSE
RATES.
HIGH PRESSURE WILL CONTINUE TO RIDGE DOWN THE EAST SLOPES OF THE
APPALACHIANS TONIGHT. THE 1031 MB SFC HIGH CENTERS OVER PENNSYLVANIA
QUALIFIES AS A CLASSICAL COLD AIR DAMMING...AND IT WILL BRING A GOOD
INFLUX AND COOL AND DRY LOW LEVEL AIR INTO THE REGION. SKIES SHOULD
CLEAR OVERNIGHT ACROSS MUCH OF NORTH CAROLINA...AT LEAST NORTH OF A
LINE FROM CHARLOTTE TO ASHEVILLE...WHILE SKIES REMAIN CLOUDY OVER
THE UPSTATE AND NE GA ATOP THE DAMMING AIRMASS. THE MOISTURE LOOKS
SHALLOW AND PCPN CHANCES WILL BE LOW AND CONFINED TO THE SRN MOST
ZONES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 245 AM WEDNESDAY...SHORT RANGE MODELS BEGIN THE SHORT RANGE
PERIOD...12Z THURS...IN GOOD AGREEMENT WITH THE POSITION OF THE BACK
DOOR COLD FRONT ACROSS THE UPPER SAVANNAH RIVER VALLEY AND SFC HIGH
PRESSURE CENTERED OVER THE MID ATLANTIC AND NEW ENGLAND STATES. AT
H5...A TROF IS EXPECTED TO PIVOT OVER THE NRN GULF...SUPPORTING THE
FORMATION OF A WEAK LOW NEAR THE MISSISSIPPI DELTA DURING THE
DAYLIGHT HOURS. AT 295K...WEAK ISENTROPIC LIFT IS EXPECTED TO
CONTINUE OVER NE GA AND THE WESTERN CAROLINAS THROUGH THURSDAY.
FORECAST SOUNDINGS INDICATE THAT THE CLOUD LAYER MAY RANGE BETWEEN
5-10 KFT...WITH LLVL NE FLOW. LLVL LIFT AND THICK MOISTURE MAY YIELD
PATCHES OF -RA TO SPRINKLES...BUT MEASURABLE QPF SEEMS UNLIKELY.
HOWEVER...GIVEN THE THICK CLOUD COVER FROM SUNRISE TO SUNSET AND
PERSISTENT NE FLOW...HIGH TEMPERATURES SHOULD VERIFY FAIRLY UNIFORM
ACROSS THE CWA ON THURSDAY. I WILL POPULATE TEMPS FROM THE NAM 2M
TEMPS...YIELDING HIGH TEMPERATURE FORECAST FROM THE MID 50S ALONG
AND EAST OF I-85 TO NEAR 50 ALONG AND NORTH OF I-40.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...THE CENTER OF HIGH PRESSURE SHOULD
SLIDE OVER THE WESTERN ATLANTIC AS LOW PRESSURE DEVELOPS OVER THE
CENTRAL PLAIN AND MID MISSISSIPPI RIVER VALLEY. FORECAST SOUNDINGS
INDICATE THAT CLOUD COVER WILL REMAIN PLENTIFUL ACROSS THE CWA
THROUGH THE PERIOD. LLVL LIFT AND SYNOPTIC SCALE FORCING WILL REMAIN
VERY WEAK...SUPPORTING MAINLY SCHC POPS ACROSS THE MTNS AND
FOOTHILLS. TEMPERATURES WILL GRADUALLY MODERATE THROUGH THE
PERIOD...REMAINING WELL ABOVE NORMAL AT NIGHT AND NEAR NORMAL FOR
FRIDAY HIGHS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 240 AM WEDNESDAY...THE MEDIUM RANGE WILL BE A PERIOD OF TIME
UNDER THE INFLUENCE OF A SOUTHERLY FLOW PRIOR TO THE ARRIVAL OF A
COLD FRONT IN THE FIRST HALF OF THE WEEK. HIGH PRESSURE WILL BE
CENTERED NEAR BERMUDA WITH A SOUTHERLY FLOW WHICH WILL CONTINUE
THROUGH THE WEEKEND AND TO START THE WEEK AHEAD OF THE FRONT. ALL
MODELS AGREE ON THE GENERAL WEEKEND SCENARIO WITH THE WARMTH AND
MOISTURE ADVECTION AND SLIGHT TO LOW CHANCE POPS FROM NE GA TO
ACROSS THE WESTERN CAROLINAS.
THE GFS MODEL IS MOST PROGRESSIVE WITH THE FRONT MOVING EAST OF OUR
AREA MONDAY EVENING. SOME CAPE VALUES OF AROUND 20 ON GFS SATURDAY
AFTERNOON IN THE NC MTNS THEN RISE TO AROUND 160 OVER THE SMOKIES
SUNDAY AFTERNOON. IT ALL COMES TOGETHER ON THE GFS MONDAY AFTERNOON
WITH CAPES OF AROUND 160 FROM NE GA TO THE NC MTNS AND 850MB WIND 40
TO 50 KTS AND 700MB WIND 55 TO 65 KTS.
THE LATEST ECMWF WHICH JUST ARRIVED IS CLOSER TO THE GFS NOW IN
TIMING AND HAS THE FRONT EAST OF OUR AREA EARLY TUESDAY MORNING.
EARLIER RUN HAD THE FRONT ARRIVING EARLY TUESDAY AFTERNOON. WIND
SPEEDS ARE COMPARABLE TO THE GFS AND NOW SINCE THE ECMWF FRONT
ARRIVES EARLIER THE CAPES ARE HIGHER AS WELL. ECMWF HAS CAPES OF
400 TO 600 MONDAY AFTERNOON ALONG THE I-85 CORRIDOR. SINCE BOTH ARE
IN BETTER AGREEMENT...WILL INCREASE POPS LATE MONDAY AND THEN
DECREASE POPS TUESDAY AS THE FRONT SHOULD BE OUT OF THE AREA TO
EAST.
TEMPERATURES WILL BE 10 OR MORE DEGREES ABOVE NORMAL AHEAD OF THE
FRONT AND THEN STARTING A COOLING TREND BEHIND THE FRONT ON DAY 7
TUESDAY.
&&
.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...INCREASING SOUTHWESTERLY FLOW JUST ABOVE THE SURFACE
WILL KEEP CONDITIONS MIXED THROUGH SUNRISE. A DECK OF ALTO-CU WILL
MOVE IN WITHIN THE NEXT COUPLE HOURS. MUCH LIKE LAST NIGHT...THE
HIGHER CLOUDS SHOULD KEEP ANY FOG OR LOW STRATUS FROM DEVELOPING.
SHOWERS ALONG THE COLD FRONT WEST OF THE MOUNTAINS HAVE LARGELY
DISSIPATED THIS MORNING. THE FRONT WILL HANG UP OVER THE MTNS WITH
THE BIG PUSH COMING OUT OF THE NORTH LATER IN THE DAY AND WINDS
SHOULD SHIFT TO THE NE AROUND 18 UTC. SHOWERS AND TSTMS WILL
EVENTUALLY DEVELOP ALONG THE FRONT...BUT THE STRONGER CONVECTION
SHOULD STAY SOUTH OF THE AIRFIELD. A PERIOD OF MVFR CIGS IS EXPECTED
TO ACCOMPANY THE FRONT.
ELSEWHERE...CLOUDS BETWEEN 6-10KFT WILL CONTINUE TO OVERSPREAD THE
REGION TONIGHT. THIS SHOULD PREVENT FOG OR RESTRICTIVE CIGS FROM
DEVELOPING AT ANY OF THE AIRFIELDS THROUGH SUNRISE. RAINFALL ALONG
THE COLD FRONT OVER ERN TN HAS LARGELY DISSIPATED. THE NEXT CHANCE
FOR SIGNIFICATION PCPN ALONG THE BNDRY WILL COME THIS AFTN AS
SHOWERS AND FEW TSTMS DEVELOP ALONG IT AS IT DROPS SOUTH ACROSS THE
REGION. I HAVEN/T ADDED THUNDER TO ANY TAFS YET...BUT IT MAY BE
NEEDED AT THE UPSTATE SITES WITH SUBSEQUENT FORECASTS. THE WINDS
WILL BE SOUTHWEST THIS MORNING...SHIFTING TO NE BEHIND THE FRONT.
NOT EXPECTING AND RESTRICTIVE CIGS OR VSBYS EXPECT PERHAPS IN A
HEAVIER SHOWER.
OUTLOOK...COLD AIR DAMMING MAY RESTRICT CIGS WEDNESDAY NIGHT INTO
FRIDAY. MORNING RESTRICTIONS IN FOG AND STRATUS ARE POSSIBLE EARLY
SATURDAY AND SUNDAY WITH FAIR CONDITIONS EXPECTED DURING THE
AFTERNOONS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...MCAVOY
SHORT TERM...NED
LONG TERM...DEO
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
302 AM EST WED DEC 5 2012
.SYNOPSIS...
A COLD FRONT WILL DRIFT SOUTHEAST ACROSS THE AREA TODAY AND REACH
THE SOUTH CAROLINA COAST THIS EVENING. HIGH PRESSURE WILL RETURN
THURSDAY AND FRIDAY. EXPECT THIS HIGH TO BECOME CENTERED OFF THE
EAST COAST WHICH WILL RESULT IN A STRONG SOUTHERLY FLOW OF WARM AND
MOIST AIR OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
A STRONG TROUGH WILL MOVE ACROSS THE NEW ENGLAND STATES
TODAY...WHILE A CUT-OFF SRN STREAM LOW DRIFTS DOWN INTO THE NRN GULF
OF MEXICO. A SFC FRONT WILL STALL OVER THE MOUNTAINS THIS
MORNING...THOUGH HEIGHT RISES ACROSS THE MID-ATLANTIC STATES WILL
SEND THE THE FRONT SURGING SOUTHWARD A LITTLE LATER IN THE DAY. WEAK
H8 FRONTOGENESIS WILL ACCOMPANY THE BNDRY...THOUGH THE DEEP LAYER
FORCING LOOKS WEAK. LOW LEVEL CONVERGENCE WILL POOL MOISTURE AHEAD
OF THE FRONT AND MOST OF THE NUMERICAL MODELS DEVELOP ENOUGH
INSTABILITY OVER THE UPSTATE...SRN NC MTNS AND NE GA TO SUPPORT
SHOWERS AND EVEN A FEW TSTMS THIS AFTERNOON. THE NAM IS A LITTLE
FASTER THAN THE GFS...WHILE THE RUC IS A HAIR SLOWER THAN EITHER
MODEL. I HAVE EXTENDED THUNDER CHANCES UP ACROSS THE SRN NC MTNS AS
I DON/T SEE THE BNDRY MAKING IT THROUGH THESE AREAS UNTIL LATE AFTN.
IN FACT...THE FRONT WILL MAKE IT THROUGH CHARLOTTE AND THE NE
UPSTATE BEFORE THE CLEARS THE ESCARPMENT. CONVECTION IS EXPECTED TO
THEN SETTLE SOUTHWARD ACROSS THE UPSTATE AND NE GA. ATTM I DON/T
EXPECT ANYTHING SEVERE OWING TO THE MOIST MID-LEVELS AND WEAK LAPSE
RATES.
HIGH PRESSURE WILL CONTINUE TO RIDGE DOWN THE EAST SLOPES OF THE
APPALACHIANS TONIGHT. THE 1031 MB SFC HIGH CENTERS OVER PENNSYLVANIA
QUALIFIES AS A CLASSICAL COLD AIR DAMMING...AND IT WILL BRING A GOOD
INFLUX AND COOL AND DRY LOW LEVEL AIR INTO THE REGION. SKIES SHOULD
CLEAR OVERNIGHT ACROSS MUCH OF NORTH CAROLINA...AT LEAST NORTH OF A
LINE FROM CHARLOTTE TO ASHEVILLE...WHILE SKIES REMAIN CLOUDY OVER
THE UPSTATE AND NE GA ATOP THE DAMMING AIRMASS. THE MOISTURE LOOKS
SHALLOW AND PCPN CHANCES WILL BE LOW AND CONFINED TO THE SRN MOST
ZONES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 245 AM WEDNESDAY...SHORT RANGE MODELS BEGIN THE SHORT RANGE
PERIOD...12Z THURS...IN GOOD AGREEMENT WITH THE POSITION OF THE BACK
DOOR COLD FRONT ACROSS THE UPPER SAVANNAH RIVER VALLEY AND SFC HIGH
PRESSURE CENTERED OVER THE MID ATLANTIC AND NEW ENGLAND STATES. AT
H5...A TROF IS EXPECTED TO PIVOT OVER THE NRN GULF...SUPPORTING THE
FORMATION OF A WEAK LOW NEAR THE MISSISSIPPI DELTA DURING THE
DAYLIGHT HOURS. AT 295K...WEAK ISENTROPIC LIFT IS EXPECTED TO
CONTINUE OVER NE GA AND THE WESTERN CAROLINAS THROUGH THURSDAY.
FORECAST SOUNDINGS INDICATE THAT THE CLOUD LAYER MAY RANGE BETWEEN
5-10 KFT...WITH LLVL NE FLOW. LLVL LIFT AND THICK MOISTURE MAY YIELD
PATCHES OF -RA TO SPRINKLES...BUT MEASURABLE QPF SEEMS UNLIKELY.
HOWEVER...GIVEN THE THICK CLOUD COVER FROM SUNRISE TO SUNSET AND
PERSISTENT NE FLOW...HIGH TEMPERATURES SHOULD VERIFY FAIRLY UNIFORM
ACROSS THE CWA ON THURSDAY. I WILL POPULATE TEMPS FROM THE NAM 2M
TEMPS...YIELDING HIGH TEMPERATURE FORECAST FROM THE MID 50S ALONG
AND EAST OF I-85 TO NEAR 50 ALONG AND NORTH OF I-40.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...THE CENTER OF HIGH PRESSURE SHOULD
SLIDE OVER THE WESTERN ATLANTIC AS LOW PRESSURE DEVELOPS OVER THE
CENTRAL PLAIN AND MID MISSISSIPPI RIVER VALLEY. FORECAST SOUNDINGS
INDICATE THAT CLOUD COVER WILL REMAIN PLENTIFUL ACROSS THE CWA
THROUGH THE PERIOD. LLVL LIFT AND SYNOPTIC SCALE FORCING WILL REMAIN
VERY WEAK...SUPPORTING MAINLY SCHC POPS ACROSS THE MTNS AND
FOOTHILLS. TEMPERATURES WILL GRADUALLY MODERATE THROUGH THE
PERIOD...REMAINING WELL ABOVE NORMAL AT NIGHT AND NEAR NORMAL FOR
FRIDAY HIGHS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 240 AM WEDNESDAY...THE MEDIUM RANGE WILL BE A PERIOD OF TIME
UNDER THE INFLUENCE OF A SOUTHERLY FLOW PRIOR TO THE ARRIVAL OF A
COLD FRONT IN THE FIRST HALF OF THE WEEK. HIGH PRESSURE WILL BE
CENTERED NEAR BERMUDA WITH A SOUTHERLY FLOW WHICH WILL CONTINUE
THROUGH THE WEEKEND AND TO START THE WEEK AHEAD OF THE FRONT. ALL
MODELS AGREE ON THE GENERAL WEEKEND SCENARIO WITH THE WARMTH AND
MOISTURE ADVECTION AND SLIGHT TO LOW CHANCE POPS FROM NE GA TO
ACROSS THE WESTERN CAROLINAS.
THE GFS MODEL IS MOST PROGRESSIVE WITH THE FRONT MOVING EAST OF OUR
AREA MONDAY EVENING. SOME CAPE VALUES OF AROUND 20 ON GFS SATURDAY
AFTERNOON IN THE NC MTNS THEN RISE TO AROUND 160 OVER THE SMOKIES
SUNDAY AFTERNOON. IT ALL COMES TOGETHER ON THE GFS MONDAY AFTERNOON
WITH CAPES OF AROUND 160 FROM NE GA TO THE NC MTNS AND 850MB WIND 40
TO 50 KTS AND 700MB WIND 55 TO 65 KTS.
THE LATEST ECMWF WHICH JUST ARRIVED IS CLOSER TO THE GFS NOW IN
TIMING AND HAS THE FRONT EAST OF OUR AREA EARLY TUESDAY MORNING.
EARLIER RUN HAD THE FRONT ARRIVING EARLY TUESDAY AFTERNOON. WIND
SPEEDS ARE COMPARABLE TO THE GFS AND NOW SINCE THE ECMWF FRONT
ARRIVES EARLIER THE CAPES ARE HIGHER AS WELL. ECMWF HAS CAPES OF
400 TO 600 MONDAY AFTERNOON ALONG THE I-85 CORRIDOR. SINCE BOTH ARE
IN BETTER AGREEMENT...WILL INCREASE POPS LATE MONDAY AND THEN
DECREASE POPS TUESDAY AS THE FRONT SHOULD BE OUT OF THE AREA TO
EAST.
TEMPERATURES WILL BE 10 OR MORE DEGREES ABOVE NORMAL AHEAD OF THE
FRONT AND THEN STARTING A COOLING TREND BEHIND THE FRONT ON DAY 7
TUESDAY.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...INCREASING SOUTHWESTERLY FLOW JUST ABOVE THE SURFACE
WILL KEEP CONDITIONS MIXED THROUGH SUNRISE. A DECK OF ALTO-CU WILL
MOVE IN WITHIN THE NEXT COUPLE HOURS. MUCH LIKE LAST NIGHT...THE
HIGHER CLOUDS SHOULD KEEP ANY FOG OR LOW STRATUS FROM DEVELOPING.
SHOWERS ALONG THE COLD FRONT WEST OF THE MOUNTAINS HAVE LARGELY
DISSIPATED THIS MORNING. THE FRONT WILL HANG UP OVER THE MTNS WITH
THE BIG PUSH COMING OUT OF THE NORTH LATER IN THE DAY AND WINDS
SHOULD SHIFT TO THE NE AROUND 18 UTC. SHOWERS AND TSTMS WILL
EVENTUALLY DEVELOP ALONG THE FRONT...BUT THE STRONGER CONVECTION
SHOULD STAY SOUTH OF THE AIRFIELD. A PERIOD OF MVFR CIGS IS EXPECTED
TO ACCOMPANY THE FRONT.
ELSEWHERE...CLOUDS BETWEEN 6-10KFT WILL CONTINUE TO OVERSPREAD THE
REGION TONIGHT. THIS SHOULD PREVENT FOG OR RESTRICTIVE CIGS FROM
DEVELOPING AT ANY OF THE AIRFIELDS THROUGH SUNRISE. RAINFALL ALONG
THE COLD FRONT OVER ERN TN HAS LARGELY DISSIPATED. THE NEXT CHANCE
FOR SIGNIFICATION PCPN ALONG THE BNDRY WILL COME THIS AFTN AS
SHOWERS AND FEW TSTMS DEVELOP ALONG IT AS IT DROPS SOUTH ACROSS THE
REGION. I HAVEN/T ADDED THUNDER TO ANY TAFS YET...BUT IT MAY BE
NEEDED AT THE UPSTATE SITES WITH SUBSEQUENT FORECASTS. THE WINDS
WILL BE SOUTHWEST THIS MORNING...SHIFTING TO NE BEHIND THE FRONT.
NOT EXPECTING AND RESTRICTIVE CIGS OR VSBYS EXPECT PERHAPS IN A
HEAVIER SHOWER.
OUTLOOK...COLD AIR DAMMING MAY RESTRICT CIGS WEDNESDAY NIGHT INTO
FRIDAY. MORNING RESTRICTIONS IN FOG AND STRATUS ARE POSSIBLE EARLY
SATURDAY AND SUNDAY WITH FAIR CONDITIONS EXPECTED DURING THE
AFTERNOONS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...MCAVOY
SHORT TERM...NED
LONG TERM...DEO
AVIATION...MCAVOY
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1206 PM CST WED DEC 5 2012
.AVIATION...
CHALLENGES WILL BE WINDS AND FOG POTENTIAL OVERNIGHT INTO EARLY
THURSDAY AS WEAK WARM ADVECTION BEGINS ACROSS THE AREA.
AXIS OF RICHEST MOISTURE UNDERNEATH OLD FRONTAL INVERSION REMAINS
EAST OF I-35 AND APPEARS ITS RETREATING SLOWLY BACK EAST. WILL NOT
CARRY ANY MVFR THIS AFTERNOON AND KEEP LIGHT E/NE WINDS AND VFR
THROUGH MID-LATE EVENING.
SURFACE RIDGE SLIDES JUST SOUTHEAST OF ALL TERMINALS AFTER MIDNIGHT
WITH WEAK SE WINDS AT THE SURFACE AND WEAK WAA WITHIN THE BOUNDARY
LAYER BETWEEN 0.5-1.5 KM. THIS IS USUALLY A SET UP FOR AT LEAST
PATCHY AND POSSIBLY DENSE ADVECTION FOG...ESPECIALLY ON THE
PERIPHERY OF RICH BOUNDARY LAYER MOISTURE THAT OUR AIRPORTS WILL BE
WITHIN. THE RAP MODEL IS HANDLING BEST TODAY AND WILL FOLLOW THE
CLOSEST...AS MOS GUIDANCE AND EVEN MODEL BUFR SOUNDINGS ARE
STRUGGLING SOME ON WHAT TO FORECAST. EXPECT MVFR VSBYS LATER THIS
EVENING FALLING INTO IFR BEFORE SUNRISE.
CONFIDENCE IS LOW REGARDING TIMING AND HOW LOW CONDITIONS GET AND
WE MAY BE IMPROVING CONDITIONS TOO SOON CONSIDERING TIME OF YEAR.
SOUTH WINDS WILL INCREASE TO NEAR 10 KT LATE MORNING WITH WARMING
TEMPS AND VFR CONDITIONS RETURNING. TIMING AND RESTRICTION TRENDS
WILL CONTINUE TO BE EVALUATED THROUGH THIS EVENING.
05/
&&
.PREV DISCUSSION... /ISSUED 349 AM CST WED DEC 5 2012/
TODAY WILL BE A COOLER DAY BEHIND YESTERDAY/S COLD FRONT.
TEMPERATURES WILL CLIMB INTO THE 60S AND LOWER 70S THIS AFTERNOON.
SOME OF THE COOLEST AFTERNOON TEMPERATURES WILL LIKELY BE FOUND
OVER THE SOUTHEASTERN COUNTIES WHERE CLOUD COVER MAY PERSIST FOR
MUCH OF THE DAY. TONIGHT...THE RETURN OF SOUTHERLY WINDS IN THE
LOWER LEVELS OF THE ATMOSPHERE WILL BRING LOW-LEVEL MOISTURE
SURGING NORTH OVER THE REGION. HOWEVER...WITH THE SURFACE WIND
SPEEDS REMAINING BELOW 5 KTS...FOG COULD LIKELY DEVELOP OVER A
GOOD PORTION OF THE AREA. FOR NOW...HAVE HIGHLIGHTED ROUGHLY THE
SOUTHEASTERN HALF OF THE CWA WITH A MENTION OF FOG IN THE
ZONES...AND THE BEST CHANCES FOR WIDESPREAD FOG WILL BE SOUTH OF A
LINE FROM GOLDTHWAITE TO CANTON. IT IS POSSIBLE AREAS OF DENSE FOG
COULD DEVELOP AND WILL CONTINUE TO ASSESS THIS POTENTIAL TODAY. A
QUICK WARM-UP IS EXPECTED TOMORROW AS THE UPPER LEVEL PATTERN
RETURNS TO NEAR ZONAL FLOW AND SOUTHWEST WINDS AT H850 BRING
WARMER TEMPERATURES OVER THE REGION. TEMPERATURES TOMORROW WILL BE
IN THE 70S REGION-WIDE.
A FRONT THAT WILL DEVELOP TONIGHT OVER THE NORTHERN ROCKIES WILL
PUSH INTO THE NORTHWEST QUADRANT OF NORTH TEXAS ON FRIDAY. THERE
IS CONSIDERABLE UNCERTAINTY AMONGST THE MODELS ON HOW EACH HANDLES
THE FRONT BUT THE OVERALL IMPACTS ARE RELATIVELY MINIMAL. THE GFS
AND NAM PUSH THIS WEAK FRONT THROUGH MOST OF THE CWA WHILE THE
ECMWF AND GEM HANG THE FRONT OVER THE NORTHERN HALF OF THE CWA.
GIVEN THE FORECASTED MODIFIED AIR BEHIND THIS FRONT AND THE UPPER
LEVEL ZONAL FLOW PATTERN...WILL SIDE WITH THE ECMWF/GEM FOR NOW
AND STALL THE FRONT GENERALLY NORTH OF I-20 FRIDAY NIGHT AND
SATURDAY. THERE IS A SLIGHT CHANCE FOR RAIN EAST OF HIGHWAY 75 AND
INTERSTATE 45 FRIDAY AFTERNOON AND NIGHT AS THE FRONT MOVES IN
AND A WEAK SHORTWAVE MOVES OVER THE REGION. PWATS WILL BE HIGHEST
OVER THE EASTERN COUNTIES BUT APPRECIABLE RAINFALL IS NOT
EXPECTED. WILL ONLY MENTION SHOWERS FOR NOW BUT AN ISOLATED
THUNDERSTORM IS POSSIBLE.
THE FORECAST FOR FRIDAY THROUGH SATURDAY NIGHT IS A LITTLE COMPLICATED
BY THE MODEL DISCREPANCIES WITH THE FRONT. ASIDE FROM THE
DIFFERENCE IN FRONTAL POSITION...THEY ALSO DIFFER IN CLOUD COVER
AND TEMPERATURES. WILL KEEP AREAS AHEAD OF THE FRONT PARTLY TO
MOSTLY CLOUDY WITH HIGHS IN THE MID TO UPPER 70S AND LOWS IN THE
50S AND 60S. BEHIND THE FRONT...TEMPERATURES WILL BE SLIGHTLY
LOWER WITH HIGHS IN THE LOWER 70S AND LOWS IN THE 40S TO AROUND 50
DEGREES.
THE BIG STORY IN THE FORECAST CONTINUES TO BE THE CANADIAN FRONT
THAT WILL COME SCREAMING THROUGH THE REGION EARLY NEXT WEEK. THE
TIMING OF THE FRONT TONIGHT IS FASTER WITH AN ARRIVAL NOW ON
SUNDAY. THE ECMWF IS SLIGHTLY SLOWER WITH THE FRONT THAN THE GFS
AND GEM AND WILL SIDE WITH THE GFS/GEM FOR NOW AS THESE FRONTS
TYPICALLY DO ARRIVE FASTER. FORECASTED HIGH TEMPERATURES ON SUNDAY
WILL BE REACHED EARLY IN THE DAY WITH THE FRONT ARRIVING DURING
THE MORNING HOURS. THE FORECAST SOUNDINGS DO NOT LOOK FAVORABLE
FOR ANY HOPE OF DECENT RAIN WHEN THE FRONT COMES THROUGH. THE
SOUNDINGS ARE PRETTY DRY WITH PWATS BELOW AN INCH...EXCEPT FOR IN
THE SOUTHEASTERN COUNTIES WHERE PWATS ARE 1-1.25 INCHES. HAVE
POPS SUNDAY AFTERNOON OVER ROUGHLY THE EASTERN 2/3RDS OF THE
CWA...THEN OVER THE FAR SOUTHERN COUNTIES ON SUNDAY NIGHT AS THE
FRONT CONTINUES TO PUSH SOUTH. AFTER THAT...A RAPID DRYING TREND
IS EXPECTED AS THE FRONT PUSHES INTO THE GULF OF MEXICO AND
FORECAST SOUNDINGS QUICKLY DRY OUT THE ATMOSPHERIC COLUMN. THE
ECMWF IS FAIRLY AGGRESSIVE WITH POST- FRONTAL PRECIPITATION
OCCURRING SUNDAY NIGHT BUT WILL KEEP THE FORECAST DRY BEHIND THE
FRONT DUE TO THE QUICK DRYING TREND ADVERTISED BY THE OTHER
MODELS. IF THERE WAS TO BE SOME POST- FRONTAL PRECIP...THE ECMWF
SUGGESTS IT WOULD BE A COLD RAIN IN OUR AREA. HOPEFULLY WE WILL
REACH SOME BETTER MODEL AGREEMENT WITH THE TIMING AND PRECIP BY
THE WEEKEND BUT WITH THE LATEST MODEL RUNS...THE CHANCE FOR
BENEFICIAL RAIN LOOKS PRETTY BLEAK.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 68 49 75 55 76 / 0 0 0 5 10
WACO, TX 70 45 76 54 77 / 0 0 0 5 10
PARIS, TX 66 43 71 52 73 / 0 0 0 5 20
DENTON, TX 68 45 74 54 74 / 0 0 0 5 10
MCKINNEY, TX 67 44 73 54 73 / 0 0 0 5 10
DALLAS, TX 68 50 75 56 77 / 0 0 0 5 10
TERRELL, TX 66 46 73 55 74 / 0 0 0 5 10
CORSICANA, TX 65 49 74 56 76 / 0 0 0 5 10
TEMPLE, TX 71 45 76 54 78 / 0 0 0 5 10
MINERAL WELLS, TX 68 42 78 50 73 / 0 0 0 5 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/82
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
726 AM CST WED DEC 5 2012
.AVIATION...
CIGS ARE ERODING JUST BEFORE THEY GET TO THE TAF SITES AND HAVE
REMOVED THEIR MENTION.
.../PREVIOUS AVIATION DISCUSSION/...
PRIMARY FORECAST CONCERN IS THE MVFR CIG MOVING TOWARD THE TAF
SITES FROM THE EAST. RAP HAS FINALLY PICKED UP ON THESE CLOUDS AND
FORECAST APPEARS REASONABLE. CIGS WILL LIKELY MAKE IT TO KDAL
AND KACT THIS MORNING...BUT SHOULD BEGIN TO DISPERSE AS THEY MOVE
WEST OF THE 35 CORRIDOR. OBVIOUSLY THIS WILL HAVE TO BE WATCHED...
BUT FOR NOW HAVE INCLUDED A TEMPO BKN020 FROM MID-LATE MORNING FOR
DFW/ACT AND PREVAILED BKN020 AT DAL. PROVIDED CIGS BREAK UP WITH
SOME HEATING TODAY...VFR SHOULD PREVAIL THIS AFTERNOON/EVENING AT
ALL TAF SITES WITH NORTH WINDS 5-10KT. OTHERWISE WILL NEED TO KEEP
AN EYE ON FOG POTENTIAL TONIGHT. WACO HAS THE BEST CHANCE FOR FOG
AND WILL INTRODUCE MVFR VSBY AFTER 9Z TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 349 AM CST WED DEC 5 2012/
TODAY WILL BE A COOLER DAY BEHIND YESTERDAY/S COLD FRONT.
TEMPERATURES WILL CLIMB INTO THE 60S AND LOWER 70S THIS AFTERNOON.
SOME OF THE COOLEST AFTERNOON TEMPERATURES WILL LIKELY BE FOUND
OVER THE SOUTHEASTERN COUNTIES WHERE CLOUD COVER MAY PERSIST FOR
MUCH OF THE DAY. TONIGHT...THE RETURN OF SOUTHERLY WINDS IN THE
LOWER LEVELS OF THE ATMOSPHERE WILL BRING LOW-LEVEL MOISTURE
SURGING NORTH OVER THE REGION. HOWEVER...WITH THE SURFACE WIND
SPEEDS REMAINING BELOW 5 KTS...FOG COULD LIKELY DEVELOP OVER A
GOOD PORTION OF THE AREA. FOR NOW...HAVE HIGHLIGHTED ROUGHLY THE
SOUTHEASTERN HALF OF THE CWA WITH A MENTION OF FOG IN THE
ZONES...AND THE BEST CHANCES FOR WIDESPREAD FOG WILL BE SOUTH OF A
LINE FROM GOLDTHWAITE TO CANTON. IT IS POSSIBLE AREAS OF DENSE FOG
COULD DEVELOP AND WILL CONTINUE TO ASSESS THIS POTENTIAL TODAY. A
QUICK WARMUP IS EXPECTED TOMORROW AS THE UPPER LEVEL PATTERN
RETURNS TO NEAR ZONAL FLOW AND SOUTHWEST WINDS AT H850 BRING
WARMER TEMPERATURES OVER THE REGION. TEMPERATURES TOMORROW WILL BE
IN THE 70S REGION-WIDE.
A FRONT THAT WILL DEVELOP TONIGHT OVER THE NORTHERN ROCKIES WILL
PUSH INTO THE NORTHWEST QUADRANT OF NORTH TEXAS ON FRIDAY. THERE
IS CONSIDERABLE UNCERTAINTY AMONGST THE MODELS ON HOW EACH HANDLES
THE FRONT BUT THE OVERALL IMPACTS ARE RELATIVELY MINIMAL. THE GFS
AND NAM PUSH THIS WEAK FRONT THROUGH MOST OF THE CWA WHILE THE
ECMWF AND GEM HANG THE FRONT OVER THE NORTHERN HALF OF THE CWA.
GIVEN THE FORECASTED MODIFIED AIR BEHIND THIS FRONT AND THE UPPER
LEVEL ZONAL FLOW PATTERN...WILL SIDE WITH THE ECMWF/GEM FOR NOW
AND STALL THE FRONT GENERALLY NORTH OF I-20 FRIDAY NIGHT AND
SATURDAY. THERE IS A SLIGHT CHANCE FOR RAIN EAST OF HIGHWAY 75 AND
INTERSTATE 45 FRIDAY AFTERNOON AND NIGHT AS THE FRONT MOVES IN
AND A WEAK SHORTWAVE MOVES OVER THE REGION. PWATS WILL BE HIGHEST
OVER THE EASTERN COUNTIES BUT APPRECIABLE RAINFALL IS NOT
EXPECTED. WILL ONLY MENTION SHOWERS FOR NOW BUT AN ISOLATED
THUNDERSTORM IS POSSIBLE.
THE FORECAST FOR FRIDAY THROUGH SATURDAY NIGHT IS A LITTLE COMPLICATED
BY THE MODEL DISCREPANCIES WITH THE FRONT. ASIDE FROM THE
DIFFERENCE IN FRONTAL POSITION...THEY ALSO DIFFER IN CLOUD COVER
AND TEMPERATURES. WILL KEEP AREAS AHEAD OF THE FRONT PARTLY TO
MOSTLY CLOUDY WITH HIGHS IN THE MID TO UPPER 70S AND LOWS IN THE
50S AND 60S. BEHIND THE FRONT...TEMPERATURES WILL BE SLIGHTLY
LOWER WITH HIGHS IN THE LOWER 70S AND LOWS IN THE 40S TO AROUND 50
DEGREES.
THE BIG STORY IN THE FORECAST CONTINUES TO BE THE CANADIAN FRONT
THAT WILL COME SCREAMING THROUGH THE REGION EARLY NEXT WEEK. THE
TIMING OF THE FRONT TONIGHT IS FASTER WITH AN ARRIVAL NOW ON
SUNDAY. THE ECMWF IS SLIGHTLY SLOWER WITH THE FRONT THAN THE GFS
AND GEM AND WILL SIDE WITH THE GFS/GEM FOR NOW AS THESE FRONTS
TYPICALLY DO ARRIVE FASTER. FORECASTED HIGH TEMPERATURES ON SUNDAY
WILL BE REACHED EARLY IN THE DAY WITH THE FRONT ARRIVING DURING
THE MORNING HOURS. THE FORECAST SOUNDINGS DO NOT LOOK FAVORABLE
FOR ANY HOPE OF DECENT RAIN WHEN THE FRONT COMES THROUGH. THE
SOUNDINGS ARE PRETTY DRY WITH PWATS BELOW AN INCH...EXCEPT FOR IN
THE SOUTHEASTERN COUNTIES WHERE PWATS ARE 1-1.25 INCHES. HAVE
POPS SUNDAY AFTERNOON OVER ROUGHLY THE EASTERN 2/3RDS OF THE
CWA...THEN OVER THE FAR SOUTHERN COUNTIES ON SUNDAY NIGHT AS THE
FRONT CONTINUES TO PUSH SOUTH. AFTER THAT...A RAPID DRYING TREND
IS EXPECTED AS THE FRONT PUSHES INTO THE GULF OF MEXICO AND
FORECAST SOUNDINGS QUICKLY DRY OUT THE ATMOSPHERIC COLUMN. THE
ECMWF IS FAIRLY AGGRESSIVE WITH POST- FRONTAL PRECIPITATION
OCCURRING SUNDAY NIGHT BUT WILL KEEP THE FORECAST DRY BEHIND THE
FRONT DUE TO THE QUICK DRYING TREND ADVERTISED BY THE OTHER
MODELS. IF THERE WAS TO BE SOME POST- FRONTAL PRECIP...THE ECMWF
SUGGESTS IT WOULD BE A COLD RAIN IN OUR AREA. HOPEFULLY WE WILL
REACH SOME BETTER MODEL AGREEMENT WITH THE TIMING AND PRECIP BY
THE WEEKEND BUT WITH THE LATEST MODEL RUNS...THE CHANCE FOR
BENEFICIAL RAIN LOOKS PRETTY BLEAK.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 68 49 75 55 76 / 0 0 0 5 10
WACO, TX 70 45 76 54 77 / 0 0 0 5 10
PARIS, TX 66 43 71 52 73 / 0 0 0 5 20
DENTON, TX 68 45 74 54 74 / 0 0 0 5 10
MCKINNEY, TX 67 44 73 54 73 / 0 0 0 5 10
DALLAS, TX 68 50 75 56 77 / 0 0 0 5 10
TERRELL, TX 66 46 73 55 74 / 0 0 0 5 10
CORSICANA, TX 65 49 74 56 76 / 0 0 0 5 10
TEMPLE, TX 71 45 76 54 78 / 0 0 0 5 10
MINERAL WELLS, TX 68 42 78 50 73 / 0 0 0 5 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
527 AM CST WED DEC 5 2012
.AVIATION...
PRIMARY FORECAST CONCERN IS THE MVFR CIG MOVING TOWARD THE TAF
SITES FROM THE EAST. RAP HAS FINALLY PICKED UP ON THESE CLOUDS AND
FORECAST APPEARS REASONABLE. CIGS WILL LIKELY MAKE IT TO KDAL
AND KACT THIS MORNING...BUT SHOULD BEGIN TO DISPERSE AS THEY MOVE
WEST OF THE 35 CORRIDOR. OBVIOUSLY THIS WILL HAVE TO BE WATCHED...
BUT FOR NOW HAVE INCLUDED A TEMPO BKN020 FROM MID-LATE MORNING FOR
DFW/ACT AND PREVAILED BKN020 AT DAL. PROVIDED CIGS BREAK UP WITH
SOME HEATING TODAY...VFR SHOULD PREVAIL THIS AFTERNOON/EVENING AT
ALL TAF SITES WITH NORTH WINDS 5-10KT. OTHERWISE WILL NEED TO KEEP
AN EYE ON FOG POTENTIAL TONIGHT. WACO HAS THE BEST CHANCE FOR FOG
AND WILL INTRODUCE MVFR VSBY AFTER 9Z TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 349 AM CST WED DEC 5 2012/
TODAY WILL BE A COOLER DAY BEHIND YESTERDAY/S COLD FRONT.
TEMPERATURES WILL CLIMB INTO THE 60S AND LOWER 70S THIS AFTERNOON.
SOME OF THE COOLEST AFTERNOON TEMPERATURES WILL LIKELY BE FOUND
OVER THE SOUTHEASTERN COUNTIES WHERE CLOUD COVER MAY PERSIST FOR
MUCH OF THE DAY. TONIGHT...THE RETURN OF SOUTHERLY WINDS IN THE
LOWER LEVELS OF THE ATMOSPHERE WILL BRING LOW-LEVEL MOISTURE
SURGING NORTH OVER THE REGION. HOWEVER...WITH THE SURFACE WIND
SPEEDS REMAINING BELOW 5 KTS...FOG COULD LIKELY DEVELOP OVER A
GOOD PORTION OF THE AREA. FOR NOW...HAVE HIGHLIGHTED ROUGHLY THE
SOUTHEASTERN HALF OF THE CWA WITH A MENTION OF FOG IN THE
ZONES...AND THE BEST CHANCES FOR WIDESPREAD FOG WILL BE SOUTH OF A
LINE FROM GOLDTHWAITE TO CANTON. IT IS POSSIBLE AREAS OF DENSE FOG
COULD DEVELOP AND WILL CONTINUE TO ASSESS THIS POTENTIAL TODAY. A
QUICK WARMUP IS EXPECTED TOMORROW AS THE UPPER LEVEL PATTERN
RETURNS TO NEAR ZONAL FLOW AND SOUTHWEST WINDS AT H850 BRING
WARMER TEMPERATURES OVER THE REGION. TEMPERATURES TOMORROW WILL BE
IN THE 70S REGION-WIDE.
A FRONT THAT WILL DEVELOP TONIGHT OVER THE NORTHERN ROCKIES WILL
PUSH INTO THE NORTHWEST QUADRANT OF NORTH TEXAS ON FRIDAY. THERE
IS CONSIDERABLE UNCERTAINTY AMONGST THE MODELS ON HOW EACH HANDLES
THE FRONT BUT THE OVERALL IMPACTS ARE RELATIVELY MINIMAL. THE GFS
AND NAM PUSH THIS WEAK FRONT THROUGH MOST OF THE CWA WHILE THE
ECMWF AND GEM HANG THE FRONT OVER THE NORTHERN HALF OF THE CWA.
GIVEN THE FORECASTED MODIFIED AIR BEHIND THIS FRONT AND THE UPPER
LEVEL ZONAL FLOW PATTERN...WILL SIDE WITH THE ECMWF/GEM FOR NOW
AND STALL THE FRONT GENERALLY NORTH OF I-20 FRIDAY NIGHT AND
SATURDAY. THERE IS A SLIGHT CHANCE FOR RAIN EAST OF HIGHWAY 75 AND
INTERSTATE 45 FRIDAY AFTERNOON AND NIGHT AS THE FRONT MOVES IN
AND A WEAK SHORTWAVE MOVES OVER THE REGION. PWATS WILL BE HIGHEST
OVER THE EASTERN COUNTIES BUT APPRECIABLE RAINFALL IS NOT
EXPECTED. WILL ONLY MENTION SHOWERS FOR NOW BUT AN ISOLATED
THUNDERSTORM IS POSSIBLE.
THE FORECAST FOR FRIDAY THROUGH SATURDAY NIGHT IS A LITTLE COMPLICATED
BY THE MODEL DISCREPANCIES WITH THE FRONT. ASIDE FROM THE
DIFFERENCE IN FRONTAL POSITION...THEY ALSO DIFFER IN CLOUD COVER
AND TEMPERATURES. WILL KEEP AREAS AHEAD OF THE FRONT PARTLY TO
MOSTLY CLOUDY WITH HIGHS IN THE MID TO UPPER 70S AND LOWS IN THE
50S AND 60S. BEHIND THE FRONT...TEMPERATURES WILL BE SLIGHTLY
LOWER WITH HIGHS IN THE LOWER 70S AND LOWS IN THE 40S TO AROUND 50
DEGREES.
THE BIG STORY IN THE FORECAST CONTINUES TO BE THE CANADIAN FRONT
THAT WILL COME SCREAMING THROUGH THE REGION EARLY NEXT WEEK. THE
TIMING OF THE FRONT TONIGHT IS FASTER WITH AN ARRIVAL NOW ON
SUNDAY. THE ECMWF IS SLIGHTLY SLOWER WITH THE FRONT THAN THE GFS
AND GEM AND WILL SIDE WITH THE GFS/GEM FOR NOW AS THESE FRONTS
TYPICALLY DO ARRIVE FASTER. FORECASTED HIGH TEMPERATURES ON SUNDAY
WILL BE REACHED EARLY IN THE DAY WITH THE FRONT ARRIVING DURING
THE MORNING HOURS. THE FORECAST SOUNDINGS DO NOT LOOK FAVORABLE
FOR ANY HOPE OF DECENT RAIN WHEN THE FRONT COMES THROUGH. THE
SOUNDINGS ARE PRETTY DRY WITH PWATS BELOW AN INCH...EXCEPT FOR IN
THE SOUTHEASTERN COUNTIES WHERE PWATS ARE 1-1.25 INCHES. HAVE
POPS SUNDAY AFTERNOON OVER ROUGHLY THE EASTERN 2/3RDS OF THE
CWA...THEN OVER THE FAR SOUTHERN COUNTIES ON SUNDAY NIGHT AS THE
FRONT CONTINUES TO PUSH SOUTH. AFTER THAT...A RAPID DRYING TREND
IS EXPECTED AS THE FRONT PUSHES INTO THE GULF OF MEXICO AND
FORECAST SOUNDINGS QUICKLY DRY OUT THE ATMOSPHERIC COLUMN. THE
ECMWF IS FAIRLY AGGRESSIVE WITH POST- FRONTAL PRECIPITATION
OCCURRING SUNDAY NIGHT BUT WILL KEEP THE FORECAST DRY BEHIND THE
FRONT DUE TO THE QUICK DRYING TREND ADVERTISED BY THE OTHER
MODELS. IF THERE WAS TO BE SOME POST- FRONTAL PRECIP...THE ECMWF
SUGGESTS IT WOULD BE A COLD RAIN IN OUR AREA. HOPEFULLY WE WILL
REACH SOME BETTER MODEL AGREEMENT WITH THE TIMING AND PRECIP BY
THE WEEKEND BUT WITH THE LATEST MODEL RUNS...THE CHANCE FOR
BENEFICIAL RAIN LOOKS PRETTY BLEAK.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 68 49 75 55 76 / 0 0 0 5 10
WACO, TX 70 45 76 54 77 / 0 0 0 5 10
PARIS, TX 66 43 71 52 73 / 0 0 0 5 20
DENTON, TX 68 45 74 54 74 / 0 0 0 5 10
MCKINNEY, TX 67 44 73 54 73 / 0 0 0 5 10
DALLAS, TX 68 50 75 56 77 / 0 0 0 5 10
TERRELL, TX 66 46 73 55 74 / 0 0 0 5 10
CORSICANA, TX 65 49 74 56 76 / 0 0 0 5 10
TEMPLE, TX 71 45 76 54 78 / 0 0 0 5 10
MINERAL WELLS, TX 68 42 78 50 73 / 0 0 0 5 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
902 PM CST THU DEC 6 2012
.UPDATE...
THE WEAK COLD FRONT CONTINUES TO DRIFT ACROSS THE AREA THIS
EVENING...STRETCHING FROM ABOUT GREEN BAY TO MINERAL POINT AT
9 PM. THIS IS ON SCHEDULE AND SHOULD EXIT THE SOUTHEAST CORNER OF
THE STATE BY OR SHORTLY AFTER 06Z. THIS GUY IS COMING THROUGH DRY
WITH ONLY SOME VERY HIGH BASED CLOUDS PRODUCING SOME VIRGA...
MAINLY SOUTH. THE MAIN CONCERN...AND IT/S NOT MUCH...IS WHAT IMPACT
A LAGGING 700MB TROF WILL HAVE AS IT COMES THROUGH LATER TONIGHT.
SOME OF THE MODELS PULL UP SOME HIGHER RH/LIGHT QPF INTO THE FAR
SOUTHEAST CORNER WITHIN A ZONE OF WEAK ISENTROPIC LIFT. IF IT
OCCURS...IT WILL BE EXCEPTIONALLY LIGHT STUFF AND IN THE FORM OF
RAIN AS TEMPS WILL BE TOO WARM FOR SNOW.
&&
.AVIATION/06Z TAFS/...
A COLD FRONT MOVING ACROSS THE AREA THIS EVENING WILL EXIT SOUTHEAST
WISCONSIN BY 06-07Z THIS EVENING. THIS IS COMING THROUGH DRY. THERE
IS A NARROW LOWER CLOUD DECK THAT HAS RECENTLY FORMED THAT IS ALIGNED
WITH THE FRONT THAT WILL BRING A BRIEF PERIOD OF MVFR CIGS AS IT
COMES THROUGH. OTHERWISE...AFTER FROPA...EXPECT VFR CONDITIONS.
THE CAVEAT IS NEAR LAKE MICHIGAN WHERE AN ONSHORE FLOW LATER
FRIDAY AFTERNOON AND NIGHT COULD RESULT IN SOME LAKE EFFECT MVFR
CIGS.
&&
.PREV DISCUSSION... /ISSUED 243 PM CST THU DEC 6 2012/
SHORT TERM...
TONIGHT - CONFIDENCE...MEDIUM
RUC/WATER VAPOR COMBO SHOWS DECENT JET MAX RACING NORTHEAST FROM IOWA
INTO WISCONSIN. RUC SHOWS A COUPLE DIFFERENT VORT CENTERS...ONE IN
CENTRAL WI AND ANOTHER IN WESTERN IOWA. SURFACE/850 TROUGHS EXIT TO
THE EAST. MODELS ALL LINGER A BIT OF QPF IN THE FAR SOUTHEAST SO
WILL KEEP SOME SMALL POPS THERE. STILL QUITE A BIT OF MID CLOUDS
UPSTREAM SO THINK CLOUDY/MOSTLY CLOUDY MUCH OF THE NIGHT.
FRIDAY - CONFIDENCE...MEDIUM
GENTLE COLD ADVECTION WITH BROAD RIDGE OF HIGH PRESSURE ACROSS THE
AREA. WITH A BRISK WSW UPPER FLOW EXPECT TO SEE A SOME MID CLOUDS
AROUND. BUFKIT/RH PROGS AND MOS IMPLY THIS. 925 TEMPS HANG AROUND 0.
LIGHT NE WIND REGIME.
FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE MEDIUM
GFS EUROPEAN AND NAM MODELS IN GOOD AGREEMENT THAT A WEAK SURFACE
COLD FRONT MOVES ACROSS THE AREA FRIDAY NIGHT ASSOCIATED WITH
SURFACE LOW PRESSURE NORTH OF THE GREAT LAKES. MODELS DEPICT THIS
DRY FRONTAL PASSAGE DEVELOPING SOME PRECIPITATION AS IT MOVES INTO
ILLINOIS SATURDAY...SO SLIGHT CHANCE OF RAIN SNOW MIX OVER EXTREME
SOUTHEAST WISCONSIN EARLY SATURDAY POSSIBLE. LIGHT NORTH WINDS
EARLY SATURDAY BECOME EAST IN THE AFTERNOON. EASTERLY WINDS OFF OF
LAKE MICHIGAN WHICH IS IN THE LOWER 40S SHOULD KEEP HIGH
TEMPERATURES IN THE 40S.
SATURDAY NIGHT THROUGH SUNDAY NIGHT...FORECAST CONFIDENCE HIGH FOR
PRECIPITATION...MEDIUM FOR PRECIPITATION TYPE
THIS IS THE BEST TIME FOR SIGNIFICANT PRECIPITATION. MOSTLY RAIN IN
THE EXTREME SOUTHEAST BECOMING A RAIN AND SNOW MIX AROUND MADISON
AND FARTHER NORTHWEST INRO CENTRAL WISCONSIN. A COMPLEX MULTIPLE
SURFACE LOW CENTERED OVER MINNESOTA TO WESTERN ILLINOIS SATURDAY
NIGHT WILL MOVE ACROSS WISCONSIN SUNDAY AHEAD OF A STRONG MID
LEVEL SHORTWAVE TROUGH.
RELATIVELY WARM SOUTHEASTERLY WINDS SATURDAY NIGHT WILL BECOME
SOUTHERLY BY SUNDAY MORNING. THE FORECAST CHALLENGE IS DETERMINGING
THE TIMING AND LOCATION OF A RAIN SNOW BOUNDARY WHICH WILL MOVE
NORTHWARD SUNDAY ACROSS SOUTHEASTERN WISCONSIN...BRINGING RAIN TO
SOUTHEAST WISCONSIN CHANGING TO RAIN SNOW MIX IN SOUTH CENTRAL
WISCONSIN. TOTAL PRECIPITATION AMOUNTS OF ONE-QUARTER TO ONE-HALF
INCH ARE EXPECTED FROM SATURDAY NIGHT TROUGH SUNDAY NIGHT WITH
HEAVIEST PRECIPITAION RATES EXPECTED EARLY SUNDAY. AS THE SUFACE
LOW MOVES ACROSS THE AREA SUNDAY AFTERNOON WINDS WILL BECOME
NORTHERLY AND SURFACE TEMPERATURES ABOVE FREEZING ACROSS THE
COUNTY WARNING AREA SUNDAY WILL DROP BELOW FREEZING OVERNIGHT AS
THE PRECIPITATION MOVES EASWARD AND ENDS SUNDAY NIGHT. NO SNOW
ACCUMULATION EXPECTED IN SOUTHEAST WISCONSIN...SOME MINOR
ACCUMULATIONS POSSIBLE LATE SUNDAY NORTHWEST OF MADISON.
LONG TERM...
MONDAY THROUGH THURSDAY...FORECAST CONFIDENCE...MEDIUM
NORTHWEST WINDS MONDAY WILL KEEP HIGH TEMPERATURES AROUND
FREEZING CLOSE TO LAKE MICHIGAN TO UPPER 20S INLAND AS SURFACE
HIGH PRESSURE BUILDS OVER THE REGION MONDAY AND MONDAY NIGHT.
SURFACE HIGH PRESSURE SOUTHEAST OF THE REGION WITH THE JET STREAM
NORTH ALONG THE CANADIAN BORDER KEEPS UPPER DISTURBANCES NORTH OF
THE AREA TUESDAY THROUGH THURSDAY.
LITTLE CHANCE OF PRECIPITATION MIDWEEK WITH SEASONABLE
TEMPERATURES.
AVIATION/00Z TAFS/...
MID DECK CONTINUES TO STREAM ACROSS SRN WI WITH UPPER JET MAX AND
SHORTWAVE TROUGH SWINGING THROUGH. PRECIP REPORTS SPOTTY AT BEST
WITH DRY LOW LEVELS. MODELS TEND TO DRY THE PRECIP UP AS IT MAKES
A MORE EASTWARD TREK FURTHER THROUGH SRN WI.
MARINE...WILL TRIM OFF THE SRN PORTION OF THE SCA AS WINDS HAVE
EASED UP. HOWEVER STILL QUITE GUSTY AROUND SHEBOYGAN SO WILL LET
THAT PORTION RIDE FOR NOW.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR LMZ643.
&&
$$
UPDATE...DAVIS
TONIGHT/FRIDAY AND AVIATION/MARINE...COLLAR
FRIDAY NIGHT THROUGH THURSDAY...HENTZ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
356 PM CST WED DEC 5 2012
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
355 PM CST WED DEC 5 2012
AT 3 PM...WATER VAPOR IMAGERY SHOWS A SHORT WAVE MOVING EAST
ACROSS EASTERN MONTANA. THE HIGH CLOUDS ASSOCIATED WITH THIS
SYSTEM HAS ALREADY ADVANCED EASTWARD INTO THE FORECAST AREA.
BUFKIT SOUNDINGS SHOW PLENTY OF DRY AIR BELOW 20K FEET. THE
MODELS ARE FAIRLY GOOD AGREEMENT THAT MODERATE TO STRONG 280-305K
ISENTROPIC LIFT WILL DEVELOP ACROSS THE AREA LATE THIS EVENING AND
THEN CONTINUE INTO MONDAY MORNING. IN ADDITION...THERE WILL
MODERATE TO STRONG 700-600 FRONTOGENESIS AROUND MIDNIGHT AND 900
TO 800 MB FRONTOGENSIS TOWARD MORNING. MUCH OF THIS LIFT GOES TO
SATURATION. AS A RESULT...NOT EXPECTING TOO MUCH PRECIPITATION
UNTIL AFTER 3 AM THURSDAY MORNING. THIS WILL BE MAINLY CONFINED
NORTH OF THE INTERSTATE 90 CORRIDOR. SOUNDINGS SUGGEST THAT THERE
WILL BE AN ELEVATED WARM LAYER. NORTH OF INTERSTATE 94...THE
HYDROMETERS WILL PARTIALLY MELT LEADING TO A MIXTURE OF
SLEET...SNOW...AND FREEZING RAIN. AS SURFACE TEMPERATURES WARM ON
THURSDAY MORNING...EXPECT THIS PRECIPITATION TO CHANGE OVER TO
RAIN. FOR THE REMAINDER OF THE AREA...THE WARM LAYER AND THE
SURFACE TEMPERATURES WILL BE WARM ENOUGH FOR THE PRECIPITATION TO
BE ALL RAIN.
ON THURSDAY AFTERNOON...A SURFACE COLD FRONT WILL BE LOCATED
ACROSS SOUTHWEST AND CENTRAL WISCONSIN AND NORTHEAST IOWA. HOWEVER
BY THIS TIME MUCH OF THE FORCING ALOFT WILL HAVE ALREADY MOVED
EAST OF THE AREA. AS A RESULT...LOWERED THE PRECIPITATION CHANCES
DOWN TO SLIGHT CHANCES.
ON THURSDAY NIGHT...THE GFS...GEM...AND ECMWF MOVE THE FRONT WELL
SOUTHEAST OF THE AREA. MEANWHILE THE NAM/WRF HOLDS THE FRONT JUST
SOUTHEAST OF THE FORECAST AREA. DUE TO THE NAM/WRF...HELD ONTO THE
20 AND 30 PERCENT PRECIPITATION PROBABILITIES FOR SNOW FOR
SOUTHWEST WISCONSIN AND NORTHEAST IOWA.
FROM FRIDAY INTO FRIDAY NIGHT...THE NAM/WRF HAS A STRONG
BAROCLINIC ZONE AND FROTOGENESIS ACROSS NORTHERN IOWA...SOUTHERN
WISCONSIN...AND NORTHERN ILLINOIS. DUE TO THIS...THEY SHOW STRONG
SURFACE CYCLOGENESIS DEVELOPING ALONG THIS BOUNDARY. AS A
RESULT...IT GENERATES A SWATH OF 2 TO 4 INCH SNOW ACROSS THE AREA
ON FRIDAY AND FRIDAY EVENING. MEANWHILE THE GFS...GEM...AND ECMWF
HAVE A MUCH WEAKER WAVE. IN ADDITION...THEY ARE ABOUT 6 HOURS
SLOWER WITH THIS WAVE. AS A RESULT...THE SNOW DOES NOT MOVE INTO
THE AREA UNTIL FRIDAY AFTERNOON AND THEN LINGERS INTO FRIDAY
NIGHT. LOOKING AT THE OPERATIONAL MODELS AND THE GFS
ENSEMBLE...BELIEVE THAT THE NAM/WRF IS AN OUTLIER...SO TRENDED
TOWARD THE OTHER SOLUTIONS. WITH THIS IN MIND...EXPECT SNOW
AMOUNTS UP TO AN INCH FROM THIS SYSTEM.
.LONG TERM...SATURDAY THROUGH WEDNESDAY
355 PM CST WED DEC 5 2012
ON SATURDAY...THE 05.12Z MODELS ARE IN GOOD AGREEMENT THAT WE WILL
SEE QUITE A BIT OF SUBSIDENCE IN THE WAKE OF THE SHORT WAVE. AS A
RESULT...TOOK OUT THE MENTION OF SNOW FOR THIS DAY.
FROM LATE SATURDAY NIGHT INTO MONDAY...THE MODELS CONTINUE TO
STRUGGLE WITH THIS TIME PERIOD. MUCH OF THIS HAS TO DEAL WHETHER
THERE WILL BE ANY PHASING OF THE NORTHERN AND SOUTHERN STREAM
SYSTEMS. BOTH THE GEM AND EMCMWF SUGGEST THAT THESE WAVES WILL NOT
PHASE...AND THE AREA WILL SEE SOME SNOW AS AN INVERTED TROUGH
MOVES NORTHEAST ACROSS THE AREA. MEANWHILE THE OPERATIONAL GFS
CONTINUES TO SHOW THAT THESE TWO SYSTEMS WILL PHASE. THIS RESULT
IN A MUCH STRONGER AND FURTHER NORTHWEST TRACK. IF THIS SCENARIO
DOES OCCUR...THERE COULD BE A BAND OF HEAVY SNOW ACROSS THE AREA.
HOWEVER THE GFS ENSEMBLE FAMILY ALSO SHOW A WIDE VARIETY OF
SOLUTIONS. ONLY 3 OF 12 WOULD SUPPORT THE OPERATIONAL GFS.
MEANWHILE THE REMAINDER EITHER SHOW THAT THE THE SOUTHERN STREAM
SYSTEM WILL BE WELL TO OUR SOUTHEAST...AND WE EITHER GET A LIGHT
DUSTING FROM THE NORTHERN STREAM OR SNOW AT ALL. AS A
RESULT...THERE IS MUCH LOWER CONFIDENCE IN THIS TIME PERIOD THAN
ONE MIGHT EXPECT BY JUST LOOKING AT THE OPERATIONAL MODELS.
&&
.AVIATION...THROUGH 18Z THURSDAY
1139 AM CST WED DEC 5 2012
MAIN AVIATION CONCERN IS WIND SHEAR THIS EVENING AND INCREASING
SOUTHERLY WINDS THIS AFTERNOON/EVENING AT BOTH LSE AND RST TAF
SITES. COLD FRONT OVER THE WESTERN DAKOTAS WILL PUSH EAST INTO
WESTERN WISCONSIN AND EASTERN IOWA THROUGH TAF FORECAST PERIOD. OUT
AHEAD OF THE COLD FRONT...A TIGHT SURFACE PRESSURE GRADIENT WILL
INCREASE SOUTHERLY WINDS THIS AFTERNOON AND EVENING WITH SUSTAINED
WINDS OF 13 TO 19 KNOTS AND GUSTS OF 20 TO 25 KNOTS EXPECTED. LATEST
05.12Z NAM AND 05.15Z RAP BUFKIT SOUNDINGS SHOW WIND SPEEDS AT
AROUND 2000 FEET ABOVE GROUND LEVEL TO BE NEAR 50 TO 55 KNOTS BY 04Z
TO 05Z THURSDAY AT BOTH TAF SITES. HAVE KEPT WIND SHEAR AT BOTH TAF
SITES. NEXT CONCERN IS PRECIPITATION CHANCES AND LOWERING OF CEILING
HEIGHTS AT TAF SITES. BOTH THE 05.12Z NAM AND 05.15Z RAP BUFKIT
SOUNDINGS INDICATE CEILING HEIGHTS LOWERING...HOWEVER THE CEILING
HEIGHTS WILL REMAIN IN THE VFR RANGE AT BOTH TAF SITES TONIGHT INTO
THURSDAY MORNING. BOTH THE 05.12Z GFS/NAM BUFKIT SOUNDINGS SHOW
ENOUGH LIFT...SATURATION OF ATMOSPHERE COLUMN AND ABOVE FREEZING
TEMPERATURES TO PRODUCE SOME RAIN SHOWERS ACROSS THE AREA AFTER
13Z THURSDAY. HAVE INTRODUCE RAIN SHOWERS AT TAF SITES AFTER 13Z
AND 15Z THURSDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
355 PM CST WED DEC 5 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...DTJ
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1211 PM CST WED DEC 5 2012
.UPDATE...
LAKE CLOUDS HAVE COME IN A BIT FARTHER AND MORE DENSE THAN
EXPECTED. WITH WIND SHIFTING TO ALLOW A LESS FAVORABLE FETCH AND
THE DELTA T DECREASING THINKING LOW CLOUDS WILL DIMINISH LATE THIS
AFTERNOON OR EARLY THIS EVENING. OTHERWISE...NO MAJOR CHANGES TO
THE FORECAST.
&&
.AVIATION/18Z TAFS/...
LAKE CLOUDS HAVE MOVED WELL ON SHORE...PARTICULARLY IN OZAUKEE AND
MILWAUKEE COUNTIES. HAVE KEPT A BROKEN DECK AT 2KFT FOR MKE AND
ENW THROUGH 21Z...THEN SCATTERED. HOPING FOR THE LESS FAVORABLE
WIND DIRECTION AND DELTA T TO HELP DIMINISH CLOUDS. HOWEVER...THE
LOW BROKEN DECK MAY PERSIST INTO THE EARLY EVENING.
DID NOT MENTION LOW LEVEL WIND SHEAR IN THE TAFS FOR TONIGHT...AS
IT LOOKS MARGINAL. WILL HAVE TO KEEP AN EYE OUT FOR IT...MAINLY IN
THE NORTHWEST AREA...AT MSN. HIGHEST WIND SPEEDS AROUND 2KFT DON/T
COME UNTIL ABOUT 10Z. BY THAT POINT...THE WARM AIR ADVECTION MAY
ALLOW ENOUGH MIXING TO RAISE SURFACE WINDS.
&&
.MARINE...
A SMALL CRAFT ADVISORY IS IN EFFECT FROM 08Z THURSDAY TO 00Z
FRIDAY. SOUTH WINDS WILL INCREASE AHEAD OF A LOW PRESSURE
DEEPENING AS IT TRACKS EASTWARD ACROSS SOUTHERN CANADA. WINDS WILL
BUILD HIGH WAVES FROM MILWAUKEE NORTH. SOUTH OF NORTH POINT THE
SHORTER FETCH IS EXPECTED TO KEEP WAVES JUST BELOW CRITERIA. THERE
WILL LIKELY STILL BE A FEW GUSTS TO 25 KNOTS SOUTH OF NORTH POINT
THOUGH. WINDS TURN SW AROUND 18Z THURSDAY AND DIMINISH BELOW
CRITERIA THROUGH THE AFTERNOON...BUT 00Z FRIDAY END TIME WILL
ALLOW WAVES TO SUBSIDE.
&&
.PREV DISCUSSION... /ISSUED 329 AM CST WED DEC 5 2012/
SHORT TERM...
TODAY.....FORECAST CONFIDENCE HIGH.
A DRY DAY WITH MID-UPPER LEVEL RIDGING BUILDING OVER REGION... AS
SURFACE HIGH PRESSURE SLIDES ACROSS THE WESTERN GREAT LAKES.
WATCHING BAND OF LAKE-EFFECT CUMULUS AROUND 3K FT DROPPING SOUTH
THROUGH LOWER MICHIGAN AND ERN HALF OF LAKE MI ON IR SATELLITE
IMAGERY. COULD BE SOME TWO-LAKE MOISTURE FEEDING THESE CLOUDS THAT
ARE ON LEADING EDGE OF POOL OF COLDEST 850 MB TEMPS THAT SLIDES BY
TO THE NORTHEAST TODAY. NW WINDS VEER NE BELOW 3K FT BY 15Z...BUT
WITH RELATIVELY WARM 850 MB TEMPS STAYING AROUND 0C WITH SUBSIDENCE
INVERSION DELTA T/S REMAIN AROUND 7C TO 9C. STEEP LAPSE RATES BELOW
2K FT/930 MB/ BUT LIMITED MOISTURE. EXCEPTION ARE RAP SOUNDINGS
WHICH INDICATE A BROKEN DECK FORMING MID AFTERNOON INTO THE EVENING.
WILL KEEP SKY COVER NO MORE THAN 50 PERCENT FOR NOW AND KEEP AN EYE
ON TRENDS.
WARM AIR ADVECTION BEGINS THIS AFTERNOON...WITH A 925 MB TEMPERATURE
GRADIENT SOUTHWEST TO NORTHEAST YIELDING NO BETTER THAN MID 30 HIGHS
IN THE NORTHEAST WITH AROUND 40 IN THE SOUTHWEST.
TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH.
WAA BRINGS MID TO HIGH LEVEL CLOUDS ACROSS THE FORECAST AREA THIS
EVENING...WITH 1-2 UBAR/SEC ISENTROPIC ADIABATIC OMEGA BRUSHING THE
NORTHWEST HALF OF CWA BETWEEN 06Z AND 12Z THURSDAY. HOWEVER MODEL
SOUNDINGS SHOW A VERY DRY LAYER BELOW 6-7K FT THAT NEVER
SATURATES...SUPPORTED BY CONDENSATION PRESSURE DEFICITS THAT NEVER
LOWER BELOW 100 MB ON 280K AND 285K SURFACES. WILL LIMIT SLIGHT
CHANCE POPS TO FAR NW. INCREASING CLOUDS AND WARM AIR ADVECTION ON
STRENGTHENING SOUTH WINDS LEADS TO A NON-DIURNAL TREND TO
TEMPERATURES...WITH LOWS AROUND 03Z THEN A SLOW RISE THROUGH
DAYBREAK.
THURSDAY THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM
STRONG LOW PRESSURE WILL ONCE AGAIN TRAVERSE EWD ACROSS CANADA
DURING THIS PERIOD BRINGING SSWLY FLOW AND LOW TO MID LEVEL WARM
ADVECTION FOR THU. THE WARM ADVECTION WILL LEAD TO WIDESPREAD
CLOUDS AND SMALL CHANCES OF RAIN FOR THU. THE CLOUDS WILL KEEP THE
TEMPS IN THE 40S THIS TIME AROUND. THE TRAILING COLD FRONT WILL
THEN SLOWLY MOVE SWD THROUGH THE AREA THU NT. MORE IMPORTANTLY...850-700
MB FRONTOGENESIS WILL BECOME ORGANIZED VIA CONFLUENT FLOW IN THAT
LAYER AS THE POLAR JET STREAM DROPS MORE SWD INTO THE USA. MOST
MODELS PRODUCE A SW TO NE BAND OF LGT RAIN THU NT SO WENT WITH
LIKELY POPS FOR THE CENTRAL AND SOUTHERN PORTIONS OF THE CWA.
LONG TERM...
FRIDAY NIGHT THROUGH TUESDAY...FORECAST CONFIDENCE LOW TO MEDIUM
A SHORTWAVE TROUGH WILL PASS FROM THE NRN PLAINS THROUGH WI FOR
FRI NT INTO SATURDAY BRINGING SMALL CHANCES OF LGT SNOW WITH THE
EXCEPTION OF A MIXTURE SAT AFTERNOON. AT THE SURFACE...WEAK HIGH
PRESSURE WILL BUILD INTO THE REGION.
DURING THE WEEKEND AN UPPER TROUGH WILL DIG INTO THE PLAINS AND
THEN SWING NEWD TOWARD THE OHIO RIVER VALLEY AND ERN GREAT LAKES.
AT THE SFC A MORE ORGANIZED SFC LOW WILL DEVELOP TO ERN IL BY 00Z MON
AND THEN NEWD THROUGH MI AND INTO QUEBEC FOR LATE ON MON. TIMING
AND STRENGTH DIFFERENCES REMAIN AMONG THE MODELS BUT NONETHELESS
SHOWING BETTER AGREEMENT. THIS SCENARIO RESULTS IN BETTER CHANCES
OF JUST SNOW AWAY FROM FAR SE WI BUT WILL STILL MENTION RAIN AND
SNOW OVER MOST OF THE AREA DUE TO UNCERTAINTY. PCPN TYPE WILL BE MAINLY
LIGHT SNOW FOR SUN NT THROUGH TUE WHILE ON THE BASKSIDE OF THE LOW
AND ANOTHER WEAK SHORTWAVE TROUGH FOR TUE.
AVIATION/12Z TAFS/...
WILL KEEP VFR CONDITIONS THROUGH THE FORECAST. CONCERN WITH
POTENTIAL MVFR LAKE-CLOUDS AS NORTH-NORTHWEST WINDS TURN NORTHEAST
LATE THIS MORNING...THEN EAST MID-AFTERNOON. SUBSIDENCE INVERSION
HOLDS STEEPER LAPSE RATES TO 2K FT OR LESS WITH LITTLE DEPTH TO
SATURATED LAYER ON NAM AND GFS SOUNDINGS...THOUGH RAP SOUNDINGS
INDICATE POTENTIAL FOR A BROKEN DECK AROUND 2K FT THIS AFTERNOON.
WITH COLD POOL THAT IS GENERATING CLOUDS OVER LOWER MICHIGAN SLIDING
BY TO THE NORTHEAST...WILL KEEP CURRENT SCATTERED 2K FT FOR TODAY
AND MONITOR DEVELOPMENTS TOWARD ISSUANCE.
COULD BE A PERIOD OF LOW-LEVEL WIND SHEAR THIS EVENING WITH 925 MB
WINDS INCREASING TO 30-35 KNOTS...BEFORE WARM AIR ADVECTION ALLOWS
ENOUGH MIXING TO RAISE SURFACE WINDS. DIFFERENTIAL IS HOVERING NEAR
BUT JUST BELOW CRITERIA SO WILL LEAVE OUT FOR NOW BUT BRIEF NEXT
SHIFT TO WATCH LATER MODEL RUNS.
MARINE...
QUIET TODAY...WITH NORTHWEST WINDS VEERING NORTHEAST AND THEN EAST
DURING THE DAY. ISSUED A SMALL CRAFT ADVISORY FOR THE NORTHERN TWO
NEARSHORE ZONES FOR 08Z THURSDAY TO 00Z FRIDAY AS SOUTH WINDS
INCREASE AHEAD OF LOW PRESSURE DEEPENING AS IT TRACKS FROM NEAR LAKE
WINNIPEG TO HUDSON BAY. THE WINDS WILL BUILD HIGH WAVES FROM
MILWAUKEE NORTH. THOUGH THERE WILL BE A FEW GUSTS TO 25 KNOTS...
WAVES SHOULD REMAIN JUST BELOW CRITERIA SOUTH OF MILWAUKEE DUE TO
MORE LIMITED FETCH. WINDS TURN SW AROUND 18Z THURSDAY AND DIMINISH
BELOW CRITERIA THROUGH THE AFTERNOON...BUT 00Z FRIDAY END TIME WILL
ALLOW WAVES TO SUBSIDE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 2 AM TO 6 PM CST THURSDAY FOR LMZ643-
644.
&&
$$
UPDATE...BROOKS
TODAY/TONIGHT AND AVIATION/MARINE...REM
THURSDAY THROUGH TUESDAY...GEHRING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1139 AM CST WED DEC 5 2012
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
348 AM CST WED DEC 5 2012
MAIN FORECAST CONCERNS THIS PACKAGE....PRECIP CHANCES/TYPES FOR ALL
OR PARTS OF THE FCST AREA AND TEMPERATURES THRU THE PERIOD.
DATA ANALYSIS AT 06Z HAD CAN HIGH PRESSURE CENTERED OVER MN WHILE
LEE TROUGHING WAS DEVELOPING OVER ALBERTA INTO MT/WY. SOME LAKE
EFFECT CLOUDS/FLURRIES OVER NORTHEAST WI...OTHERWISE CLEAR SKIES OR
SOME CIRRUS OVER THE REGION EARLY THIS MORNING. LIGHT WINDS AND THE
CLEAR/MOSTLY CLEAR SKIES WITH THE HIGH ALLOWING TEMPS TO DROP
CLOSER TO EARLY DEC LOWS THIS MORNING...WITH TEENS TO MID 20S COMMON
ACROSS MUCH OF MN/IA/WI.
NO PROBLEMS NOTED WITH 05.00Z MODEL INITIALIZATIONS. IN FACT ALL
LOOK QUITE GOOD. EVEN WITH A GOOD COMMON START...MODELS ALREADY
DIFFER FOR TONIGHT/THU WITH THE LOWER LEVEL MOISTURE AND PRECIP
CHANCES FOR THE AREA. SOME DIFFERENCES CONTINUE INTO FRI NIGHT BUT
THEY DO NOT LOOK TO GROW PROGRESSIVELY BIGGER FROM THOSE OF
TONIGHT/THU. DPROG/DT OF 500MB HGTS AT 05.00Z SHOWED THE MODEL RUNS
OF 03.00Z AND 04.00Z VERIFIED WELL ACROSS NOAM/EASTERN PAC. MODEL
CONSENSUS HAS TRENDED TOWARD FASTER OF EARLIER RUNS WITH FEATURES
FROM THE NORTHEAST CONUS TO EASTERN PAC. MODELS CONTINUE GENERAL
TREND OF DEVELOPING TROUGHING OVER THE CENTRAL/WESTERN CONUS IN THE
THU NIGHT TO FRI NIGHT PERIOD BUT PLENTY OF DIFFERENCES REMAIN WITH
STRENGTH/TIMING OF SHORTWAVE FEATURES THRU THIS FLOW. TREND FAVORS A
STRONGER FEATURE TO MOVE TOWARD/ACROSS THE UPPER MIDWEST FRI/FRI
NIGHT AND MORE RIDGING IN THE EASTERN PAC BY 12Z SAT. SOMEWHAT
BETTER RUN-TO-RUN CONSISTENCY BY ECMWF. PER SFC OBS...MODELS ALL
LOOKED TO BE PERFORMING QUITE WELL WITH THE SFC MASS FIELDS AT 06Z.
WV IMAGERY SHOWED ALL LOOKED GOOD WITH THE NOAM/ EASTERN PAC
SHORTWAVE DETAILS. NO CLEAR MODEL FAVORITE AGAIN...PERHAPS A SLIGHT
LEAN TOWARD THE ECMWF...THUS FAVORED THE MODEL/ENSEMBLE CONSENSUS.
GIVEN THE DETAIL DIFFERENCES ALREADY TONIGHT AND IMPACTS ON SENSIBLE
WEATHER...SHORT-TERM FCST CONFIDENCE AVERAGE THIS CYCLE.
IN THE SHORT TERM...ANOTHER QUIET DAY TODAY AS THE SFC HIGH SLIPS
SOUTHEAST OF THE AREA BUT A DRY SFC-700MB AIRMASS REMAINS OVER THE
AREA. SFC-700MB RIDGE AXIS MOVES EAST OF THE AREA BY 18Z WITH
INCREASING LOW LEVEL WARM ADVECTION SPREADING OVER THE AREA DURING
THE AFTERNOON. 925MB TEMPS ALREADY WARM TO -2C TO +4C BY 00Z THU...
BUT THIS WARMING OFFSET BY AN INCREASE OF HIGH LEVEL MOISTURE/
CLOUDS STREAMING EAST AHEAD OF THE NEXT TROUGH MOVING ACROSS THE
NORTHERN ROCKIES. WITH THE SNOW-FREE GROUND AND SOME SUNSHINE THIS
MORNING...HIGHS TODAY WILL AGAIN BE ABOVE NORMAL.
STRONGEST OF THE 925-700MB WARM ADVECTION/THERMO-DYNAMIC FORCING
MOVES ACROSS THE AREA TONIGHT. MUCH OF THIS CONTINUES TO GO INTO
WARMING...WITH 925MB TEMPS IN THE +2C TO +6C RANGE BY 12Z THU. WITH
THE LOWER LEVEL AIR MASS SOURCE REGION FROM THE CENTRAL PLAINS...
SFC-700MB LAYER STRUGGLES TO SATURATE...ESPECIALLY OVER THE SOUTHERN
2/3 OF THE FCST AREA. EVEN WITH THE DETAIL DIFFERENCES...BETTER
MODEL SIGNAL THAT SOME SFC-700MB SATURATION WILL OCCUR OVER THE FAR
NORTH END OF THE FCST AREA LATER TONIGHT/EARLY THU WHEN THE
STRONGEST OF THE LOWER LEVEL THERMO-DYNAMIC FORCING/LIFT PASS.
RAISED PRECIP CHANCES ACROSS THE NORTH END OF THE FCST AREA INTO THE
50-60 PERCENT RANGE LATE TONIGHT/THU MORNING WHILE MAINTAINING LOWER
PRECIP CHANCES OR A DRY FCST OVER THE CENTRAL/SOUTH PORTIONS OF THE
FCST AREA. THERMAL PROFILES ACROSS THE FAR NORTH END OF THE FCST
AREA CONTINUE TO INDICATE POTENTIAL FOR A WINTRY MIX...DEPENDING
ON HOW MUCH EVAPORATIVE COOLING OCCURS AS THE LOWER LEVEL SATURATE
FROM ABOVE. CONTINUED THE -RA/-FZRA/IP/-SN MENTION OVER THE
NORTH/EAST ENDS OF THE FCST AREA LATE TONIGHT/EARLY THU MORNING
UNTIL THE COLUMN AND/OR BOUNDARY LAYER BECOMES TOO WARM FOR THE
MIXED TYPES. ANY PRECIP AMOUNT AGAIN LOOK TO BE QUITE LIGHT.
SFC-500MB TROUGH AXIS SLIDES SOUTHEAST ACROSS THE AREA THU WITH
SOME 850-700MB FN CONVERGENCE AND GREATER 925-700MB MOISTURE/
SATURATION. CONTINUED RAIN CHANCES IN THE 25-50 PERCENT RANGE THU
AFTERNOON AND OVER THE SOUTHEAST END OF THE FCST AREA THU EVENING.
BRIEF BREAK FROM THE PRECIP CHANCES LATE THU NIGHT/FRI MORNING
BEFORE THE NEXT SHORTWAVE AND STRONGER ROUND OF 850-500MB FN
CONVERGENCE MOVE INTO THE AREA ALREADY FRI AFTERNOON. QUESTIONS/
DIFFERENCES AGAIN REMAIN WITH AMOUNT OF MOISTURE/SATURATION IN THE
SFC-700MB LAYER FRI AFTERNOON/EVENING BUT MODEL TREND IS TOWARD MORE
MOISTURE/SATURATION AND PRECIP PRODUCTION THESE PERIODS. MODEL
DIFFERENCES ALSO CONTINUE WITH THE LOWER LEVEL THERMAL PROFILES FRI
AFTERNOON/NIGHT...SOME COLD ENOUGH FOR ALL -SN SOME WITH A -RA/-SN
MIX BECOMING ALL SNOW. ADDED A 20-30 PERCENT -RA/-SN CHANCE TO MUCH
OF THE FCST AREA FOR FRI AFTERNOON AND CONTINUED THE 30 PERCENT -SN
CHANCE FRI NIGHT. IF THE COLDER...MORE MOIST SOLUTIONS ARE MORE
CORRECT...MUCH OF THE FCST AREA COULD SEE AND INCH OR TWO OF
SNOWFALL FRI AFTERNOON/ NIGHT.
FAVORING THE MODEL/ENSEMBLE CONSENSUS...GENERALLY FAVORED A BLEND OF
THE NUMERICAL TEMP GUIDANCE FOR HIGHS/LOWS TODAY THRU FRI NIGHT.
WITH THE PRECIP/SNOW CHANCES FRI AFTERNOON...DID TREND TOWARD COOLER
OF GUIDANCE HIGHS ON FRI.
.LONG TERM...SATURDAY THROUGH TUESDAY
348 AM CST WED DEC 5 2012
AS PREVIOUS FORECASTER STATED...A LOT OF UNCERTAINTY REMAINS IN THE
EXTENDED FORECAST. 05.00Z MEDIUM RANGE MODELS ARE SIMILAR ENOUGH
WITH THE BIG PICTURE OF A LONGWAVE TROUGH DEVELOPING INTO THE
CENTRAL CONUS BY SUN THEN MOVING IT INTO THE EASTERN CONUS BY TUE.
PLENTY OF TIMING/STRENGTH DETAIL DIFFERENCES WITH THE EVOLUTION OF
SHORTWAVES DROPPING INTO AND THRU THIS TROUGH BY SUN-TUE. THESE
DIFFERENCES BIG ENOUGH TO HAVE LARGE IMPACTS ON THE RESULTING
SENSIBLE WEATHER ON DAYS 5 THRU 7...THUS LONG-TERM FCST CONFIDENCE
REMAINS BELOW AVERAGE.
SOME CONSENSUS FOR WEAK HIGH PRESSURE AND SHORTWAVE RIDGING ALOFT
TO BUILD ACROSS THE UPPER MIDWEST IN THE WAKE OF THE FRI/FRI NIGHT
SYSTEM. GIVEN THE DETAIL DIFFERENCES FRI...A LINGERING SMALL -SN
CHANCE ON SAT PER THE MODEL/ENSEMBLE CONSENSUS LOOKS REASONABLE FOR
NOW. FOR SUN THRU TUE...ONE OR MORE OF THE MODELS SWING A
SIGNIFICANT MID LEVEL SHORTWAVE...SFC LOW/TROUGH AND DEEP LAYERED
FORCING/LIFT NORTHEAST NEAR OR ACROSS THE UPPER MIDWEST. MODEL
TRENDS SHOWING THE AIRMASS OVER THE AREA DURING THIS TIME WOULD BE
COLD ENOUGH FOR THE BULK OF ANY PRECIP IN SUN-TUE TIME-FRAME WOULD
FALL AS SNOW. WITH ALL THE DIFFERENCES...MADE NO CHANGES
TO THE MODEL/ENSEMBLE CONSENSUS DATA...BOTH PRECIP CHANCES AND
HIGHS/LOWS...IN THE DAY 5-7 FCST GRIDS.
&&
.AVIATION...THROUGH 18Z THURSDAY
1139 AM CST WED DEC 5 2012
MAIN AVIATION CONCERN IS WIND SHEAR THIS EVENING AND INCREASING
SOUTHERLY WINDS THIS AFTERNOON/EVENING AT BOTH LSE AND RST TAF
SITES. COLD FRONT OVER THE WESTERN DAKOTAS WILL PUSH EAST INTO
WESTERN WISCONSIN AND EASTERN IOWA THROUGH TAF FORECAST PERIOD. OUT
AHEAD OF THE COLD FRONT...A TIGHT SURFACE PRESSURE GRADIENT WILL
INCREASE SOUTHERLY WINDS THIS AFTERNOON AND EVENING WITH SUSTAINED
WINDS OF 13 TO 19 KNOTS AND GUSTS OF 20 TO 25 KNOTS EXPECTED. LATEST
05.12Z NAM AND 05.15Z RAP BUFKIT SOUNDINGS SHOW WIND SPEEDS AT
AROUND 2000 FEET ABOVE GROUND LEVEL TO BE NEAR 50 TO 55 KNOTS BY 04Z
TO 05Z THURSDAY AT BOTH TAF SITES. HAVE KEPT WIND SHEAR AT BOTH TAF
SITES. NEXT CONCERN IS PRECIPITATION CHANCES AND LOWERING OF CEILING
HEIGHTS AT TAF SITES. BOTH THE 05.12Z NAM AND 05.15Z RAP BUFKIT
SOUNDINGS INDICATE CEILING HEIGHTS LOWERING...HOWEVER THE CEILING
HEIGHTS WILL REMAIN IN THE VFR RANGE AT BOTH TAF SITES TONIGHT INTO
THURSDAY MORNING. BOTH THE 05.12Z GFS/NAM BUFKIT SOUNDINGS SHOW
ENOUGH LIFT...SATURATION OF ATMOSPHERE COLUMN AND ABOVE FREEZING
TEMPERATURES TO PRODUCE SOME RAIN SHOWERS ACROSS THE AREA AFTER
13Z THURSDAY. HAVE INTRODUCE RAIN SHOWERS AT TAF SITES AFTER 13Z
AND 15Z THURSDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
348 AM CST WED DEC 5 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...DTJ
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
329 AM CST WED DEC 5 2012
.SHORT TERM...
TODAY.....FORECAST CONFIDENCE HIGH.
A DRY DAY WITH MID-UPPER LEVEL RIDGING BUILDING OVER REGION... AS
SURFACE HIGH PRESSURE SLIDES ACROSS THE WESTERN GREAT LAKES.
WATCHING BAND OF LAKE-EFFECT CUMULUS AROUND 3K FT DROPPING SOUTH
THROUGH LOWER MICHIGAN AND ERN HALF OF LAKE MI ON IR SATELLITE
IMAGERY. COULD BE SOME TWO-LAKE MOISTURE FEEDING THESE CLOUDS THAT
ARE ON LEADING EDGE OF POOL OF COLDEST 850 MB TEMPS THAT SLIDES BY
TO THE NORTHEAST TODAY. NW WINDS VEER NE BELOW 3K FT BY 15Z...BUT
WITH RELATIVELY WARM 850 MB TEMPS STAYING AROUND 0C WITH SUBSIDENCE
INVERSION DELTA T/S REMAIN AROUND 7C TO 9C. STEEP LAPSE RATES BELOW
2K FT/930 MB/ BUT LIMITED MOISTURE. EXCEPTION ARE RAP SOUNDINGS
WHICH INDICATE A BROKEN DECK FORMING MID AFTERNOON INTO THE EVENING.
WILL KEEP SKY COVER NO MORE THAN 50 PERCENT FOR NOW AND KEEP AN EYE
ON TRENDS.
WARM AIR ADVECTION BEGINS THIS AFTERNOON...WITH A 925 MB TEMPERATURE
GRADIENT SOUTHWEST TO NORTHEAST YIELDING NO BETTER THAN MID 30 HIGHS
IN THE NORTHEAST WITH AROUND 40 IN THE SOUTHWEST.
TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH.
WAA BRINGS MID TO HIGH LEVEL CLOUDS ACROSS THE FORECAST AREA THIS
EVENING...WITH 1-2 UBAR/SEC ISENTROPIC ADIABATIC OMEGA BRUSHING THE
NORTHWEST HALF OF CWA BETWEEN 06Z AND 12Z THURSDAY. HOWEVER MODEL
SOUNDINGS SHOW A VERY DRY LAYER BELOW 6-7K FT THAT NEVER
SATURATES...SUPPORTED BY CONDENSATION PRESSURE DEFICITS THAT NEVER
LOWER BELOW 100 MB ON 280K AND 285K SURFACES. WILL LIMIT SLIGHT
CHANCE POPS TO FAR NW. INCREASING CLOUDS AND WARM AIR ADVECTION ON
STRENGTHENING SOUTH WINDS LEADS TO A NON-DIURNAL TREND TO
TEMPERATURES...WITH LOWS AROUND 03Z THEN A SLOW RISE THROUGH
DAYBREAK.
THURSDAY THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM
STRONG LOW PRESSURE WILL ONCE AGAIN TRAVERSE EWD ACROSS CANADA
DURING THIS PERIOD BRINGING SSWLY FLOW AND LOW TO MID LEVEL WARM
ADVECTION FOR THU. THE WARM ADVECTION WILL LEAD TO WIDESPREAD
CLOUDS AND SMALL CHANCES OF RAIN FOR THU. THE CLOUDS WILL KEEP THE
TEMPS IN THE 40S THIS TIME AROUND. THE TRAILING COLD FRONT WILL
THEN SLOWLY MOVE SWD THROUGH THE AREA THU NT. MORE IMPORTANTLY...850-700
MB FRONTOGENESIS WILL BECOME ORGANIZED VIA CONFLUENT FLOW IN THAT
LAYER AS THE POLAR JET STREAM DROPS MORE SWD INTO THE USA. MOST
MODELS PRODUCE A SW TO NE BAND OF LGT RAIN THU NT SO WENT WITH
LIKELY POPS FOR THE CENTRAL AND SOUTHERN PORTIONS OF THE CWA.
.LONG TERM...
FRIDAY NIGHT THROUGH TUESDAY...FORECAST CONFIDENCE LOW TO MEDIUM
A SHORTWAVE TROUGH WILL PASS FROM THE NRN PLAINS THROUGH WI FOR
FRI NT INTO SATURDAY BRINGING SMALL CHANCES OF LGT SNOW WITH THE
EXCEPTION OF A MIXTURE SAT AFTERNOON. AT THE SURFACE...WEAK HIGH
PRESSURE WILL BUILD INTO THE REGION.
DURING THE WEEKEND AN UPPER TROUGH WILL DIG INTO THE PLAINS AND
THEN SWING NEWD TOWARD THE OHIO RIVER VALLEY AND ERN GREAT LAKES.
AT THE SFC A MORE ORGANIZED SFC LOW WILL DEVELOP TO ERN IL BY 00Z MON
AND THEN NEWD THROUGH MI AND INTO QUEBEC FOR LATE ON MON. TIMING
AND STRENGTH DIFFERENCES REMAIN AMONG THE MODELS BUT NONETHELESS
SHOWING BETTER AGREEMENT. THIS SCENARIO RESULTS IN BETTER CHANCES
OF JUST SNOW AWAY FROM FAR SE WI BUT WILL STILL MENTION RAIN AND
SNOW OVER MOST OF THE AREA DUE TO UNCERTAINTY. PCPN TYPE WILL BE MAINLY
LIGHT SNOW FOR SUN NT THROUGH TUE WHILE ON THE BASKSIDE OF THE LOW
AND ANOTHER WEAK SHORTWAVE TROUGH FOR TUE.
&&
.AVIATION/12Z TAFS/...
WILL KEEP VFR CONDITIONS THROUGH THE FORECAST. CONCERN WITH
POTENTIAL MVFR LAKE-CLOUDS AS NORTH-NORTHWEST WINDS TURN NORTHEAST
LATE THIS MORNING...THEN EAST MID-AFTERNOON. SUBSIDENCE INVERSION
HOLDS STEEPER LAPSE RATES TO 2K FT OR LESS WITH LITTLE DEPTH TO
SATURATED LAYER ON NAM AND GFS SOUNDINGS...THOUGH RAP SOUNDINGS
INDICATE POTENTIAL FOR A BROKEN DECK AROUND 2K FT THIS AFTERNOON.
WITH COLD POOL THAT IS GENERATING CLOUDS OVER LOWER MICHIGAN SLIDING
BY TO THE NORTHEAST...WILL KEEP CURRENT SCATTERED 2K FT FOR TODAY
AND MONITOR DEVELOPMENTS TOWARD ISSUANCE.
COULD BE A PERIOD OF LOW-LEVEL WIND SHEAR THIS EVENING WITH 925 MB
WINDS INCREASING TO 30-35 KNOTS...BEFORE WARM AIR ADVECTION ALLOWS
ENOUGH MIXING TO RAISE SURFACE WINDS. DIFFERENTIAL IS HOVERING NEAR
BUT JUST BELOW CRITERIA SO WILL LEAVE OUT FOR NOW BUT BRIEF NEXT
SHIFT TO WATCH LATER MODEL RUNS.
&&
.MARINE...
QUIET TODAY...WITH NORTHWEST WINDS VEERING NORTHEAST AND THEN EAST
DURING THE DAY. ISSUED A SMALL CRAFT ADVISORY FOR THE NORTHERN TWO
NEARSHORE ZONES FOR 08Z THURSDAY TO 00Z FRIDAY AS SOUTH WINDS
INCREASE AHEAD OF LOW PRESSURE DEEPENING AS IT TRACKS FROM NEAR LAKE
WINNIPEG TO HUDSON BAY. THE WINDS WILL BUILD HIGH WAVES FROM
MILWAUKEE NORTH. THOUGH THERE WILL BE A FEW GUSTS TO 25 KNOTS...
WAVES SHOULD REMAIN JUST BELOW CRITERIA SOUTH OF MILWAUKEE DUE TO
MORE LIMITED FETCH. WINDS TURN SW AROUND 18Z THURSDAY AND DIMINISH
BELOW CRITERIA THROUGH THE AFTERNOON...BUT 00Z FRIDAY END TIME WILL
ALLOW WAVES TO SUBSIDE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 2 AM TO 6 PM CST THURSDAY FOR LMZ643-
644.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...REM
THURSDAY THROUGH TUESDAY...GEHRING
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
859 PM MST THU DEC 6 2012
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 345 PM MST THU DEC 6 2012
DENDRITIC LAYER IS DRYING OUT ACROSS THE NORTHERN CWA THIS AFTERNOON
WITH MOST AREAS NORTH OF HIGHWAY 50 SEEING MAINLY CLOUDS AT MOUNTAIN
TOP LEVEL AND SOME ISOLATED OROGRAPHIC SHOWERS. DOWN SOUTH...MOIST
UNSTABLE FLOW CONTINUES TO PROGRESS SLOWLY SOUTHWARD ACROSS THE SAN
JUANS. WEB CAMS AROUND TEX AND ALONG THE RED MOUNTAIN PASS INDICATED
THE CONVECTION WAS AIDING THE DENDRITIC GROWTH WITH BIG FLAKES
COMING DOWN. WARM LOW LEVEL ROAD TEMPERATURES HOWEVER HAVE NOT BEEN
FAVORABLE FOR THE SNOW TO ACCUMULATE BELOW 9000 FEET. SNOTEL DATA
NOT MUCH HELP IN THIS WARM AIRMASS BUT SWE HAS BEEN INCREASING
ACROSS THE HIGHER LOCATIONS BY A FEW TENTHS. THERE SHOULD BE A
DECREASING TREND THROUGH THE EVENING AS THE MOISTURE PLUME CONTINUES
TO BE FORCED SOUTHWARD AND THE CONVECTIVE ELEMENT WANES.
12Z U/A ANALYSIS CONTINUED TO SHOW TWO MAIN VORTICES OVER
NOAM ...ONE ACROSS THE GULF AND LANDMASS OF AK AND THE OTHER
CENTERED NORTH OF HUDSON BAY. THESE TWO FEATURES WILL BEGIN TO
INTERACT MORE DIRECTLY OVER THE NEXT 24 TO 48 HOURS AND PULL BOTH
MOISTURE AND VERY COLD AIR INTO THE WESTERN CONUS AND BRING THE MUCH
ANTICIPATED PATTERN CHANGE.
DARKENING IN WATER VAPOR IMAGERY ACROSS WESTERN WASHINGTON THIS
AFTERNOON INDICATES THE PUSH OF THE BRANCH OF THE POLAR JET MAX
INTO THE WEST. THIS BROAD CYCLONIC JET WILL PUSH ACROSS THE
NORTHERN ROCKIES INTO THE PLAINS BEGINNING TONIGHT AND SLOWLY SAG
TOWARD THE NORTHERN COLORADO BORDER THROUGH TOMORROW NIGHT. 305K
MOISTURE TRANSPORT VECTORS SHOWS A CONTINUAL FEED OF PACIFIC
MOISTURE BEING PULLED ALONG WITH THIS JET DIRECTED AT NORTHERN
UTAH AND COLORADO WELL INTO THE WEEKEND. WHAT WILL BE LACKING WITH
THIS MOISTURE TONIGHT WILL BE LARGE SCALE ASCENT. 1.5 PVU PRESSURE
PLOTS SHOW THE LEAD PIECE OF ENERGY FROM THE DECAYING WESTERN LOW
TRANSLATING ACROSS ACROSS THE NORTHERN ROCKIES. HOWEVER THIS WAVE
WILL CONTRIBUTE AN INCREASE TO THE WESTERLY MID LEVEL FLOW OVER
NORTHERN UTAH AND COLORADO AND PUSH IN COLDER AIR ALOFT. WITH THE
THE LACK OF STRONG DYNAMICS AND A SURFACE FOCUS...THE NORTHERN AND
CENTRAL HIGH COUNTRY LOOK FAVORED FOR PERIODIC OROGRAPHIC SNOW
SHOWERS THROUGH SATURDAY MORNING. THE SOUTHERN MOUNTAIN WILL BE ON
THE OUTSIDE LOOKING IN DURING THIS TIME. DENDRITIC SATURATION
LOOKS TO TAKE PLACE ACROSS THE NORTHERN MOUNTAINS AFTER MIDNIGHT
AND SPREAD SOUTHWARD TOWARD THE I-70 CORRIDOR BY TOMORROW
AFTERNOON. H7 TEMPS WILL BE COOLING TO THE -6 TO -10 BY MID
MORNING ON FRIDAY SO SOME SNOWFALL MAY MAKE IT DOWN THE SBS AND
HDN AREAS FOR A DUSTING OF SNOW. THE MAIN FOCUS HOWEVER WILL BE
OVER THE FLAT TOPS...PARK AND GORE RANGES WHERE GENERALLY 2 TO 3
INCHES IS EXPECTED BY TOMORROW EVENING...WITH LOCALLY HIGHER
AMOUNTS POSSIBLE ON NORTHWEST FACING SLOPES.
LARGE SCALE ASCENT WILL INCREASE OVER THE NORTH FRIDAY NIGHT AS
THE RR OF THE UPPER JET MOVES OVER SOUTHERN WYOMING AND THE NEXT
UPSTREAM WAVE PUSHES INTO THE NW WYOMING. MOIST WESTERLY
OROGRAPHICS ARE STILL IN PLACE SO SNOW SHOWERS ACROSS THE NORTHERN
COLORADO MOUNTAINS STILL A GOOD BET AND RAISED POPS. THESE WILL
ONLY INCREASE THROUGH THE DAY AS THE COLD FRONT FROM THE NORTH
APPROACHES. TEMPERATURES WILL BE A BIT COOLER THE NEXT WITH LESS
CLOUD COVER TONIGHT AND COOLER AIR ARRIVING FRIDAY NIGHT. HIGHS
TOMORROW WILL BEGIN A DONN WARD TREND BY A FEW DEGREES BUT STILL
REMAIN ABOVE EARLY DECEMBER NORMALS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 345 PM MST THU DEC 6 2012
MODELS REMAIN CONSISTENT IN SHOWING A CHANGE TO COLDER AND POSSIBLY
UNSETTLED WEATHER FOR ERN UT/WRN CO...BEGINNING THIS WEEKEND AND
CONTINUING THROUGH MUCH OF NEXT WEEK. GFS AND ECMWF ENSEMBLES
INDICATE THE DEVELOPMENT OF A LARGE TROUGH ACROSS MUCH OF THE CONUS
WHILE AN UPPER RIDGE AMPLIFIES IN THE NERN PACIFIC OCEAN. THE
CHALLENGE REMAINS THE TRACK OF THE PERIODIC SHORTWAVES THAT TOP THE
RIDGE AND DROP INTO THE WESTERN AND CENTRAL USA.
SATURDAY-SUNDAY: THE FIRST OF THESE SHORTWAVES DROPS OUT OF THE GULF
OF AK AND SWINGS ACROSS THE NORTHERN ROCKIES ON SATURDAY...
EVENTUALLY DEVELOPING A SURFACE LOW OVER THE DAKOTAS. THE TRAILING
COLD FRONT LOOKS TO DROP INTO THE NORTH DURING THE DAY ON
SATURDAY....THEN SWEEP ACROSS THE REMAINDER OF THE FORECAST AREA SAT
NIGHT AS THE UPPER JET DIGS A POSITIVE-TILTED TROUGH SOUTH ACROSS
THE AREA. AS DESCRIBED IN LAST NIGHT/S DISCUSSION...DYNAMIC AND
FRONTAL FORCING COMBINED WITH OROGRAPHIC LIFT PROVIDED BY STRONG
WESTERLIES AND A MOISTENING AND LOWERING DENDRITIC SNOW GROWTH
REGION WILL BRING MEASURABLE SNOW TO THE NORTHERN MOUNTAIN BY
SATURDAY AFTERNOON. STRONG GUSTY WEST WINDS WILL CREATE AREAS OF
BLOWING SNOW SAT AFTERNOON. SNOW THEN SPREADS INTO THE CENTRAL AND
SOUTHERN MOUNTAINS SAT NIGHT...WITH FLOW SHIFTING TO THE NW AND N.
COLDER AIR BEHIND THE FRONT WILL QUICKLY DROP SNOW LEVELS TO VALLEY
FLOORS. NW-N FLOW SHOULD KEEP SOME SNOW SNOW SHOWERS OVER THE CO
MTNS ON SUNDAY WHILE DRYING AND SUBSIDENCE MOVE INTO ERN UT AND NW
CO BEHIND THE UPPER TROUGH.
A BIT SURPRISED AT THE PAUCITY OF SNOWFALL GENERATED BY THE 12Z NAM
AND PREFERRED THE GFS/ECMWF WHICH TRACKED THE DIGGING TROUGH SAT
NIGHT A LITTLE FARTHER WEST. BUT BECAUSE OF THIS...UNCERTAINTY
PERSISTS. INITIAL ESTIMATES FOR SNOW ACCUMS FOR SAT-SUNDAY MORNING
LOOK TO BE 5-10 INCHES FOR THE NRN CO MTNS AND THE CENTRAL MTNS NEAR
THE DIVIDE. LESSER AMOUNTS ELSEWHERE THOUGH AREAS TO WATCH ARE THE
NORTH SIDES OF GRAND MESA AND THE SAN JUANS IN THE NW-N FLOW. ERN
UT...HOWEVER...LOOKS TO RECEIVE THE LEAST.
COLDER TEMPS ARRIVE BEHIND THE FRONT WITH HIGH TEMPS SUNDAY PERHAPS
15-20 DEGREES COLDER THAN THE HIGH TEMPS ON FRIDAY. OVERNIGHT LOWS
IN THE SINGLE DIGITS AND TEENS ARE EXPECTED SUNDAY NIGHT AREA-WIDE.
ISSUED A SPECIAL WEATHER STATEMENT EARLIER THIS AFTERNOON TO ADDRESS
THE UPCOMING CHANGE TO COLDER WEATHER AND POSSIBILITY OF SIGNIFICANT
SNOWFALL.
MONDAY-THURSDAY: COOL NORTHWESTERLY FLOW EXPECTED THROUGH MIDWEEK.
ANOTHER SHORTWAVE DIVES THROUGH THE REGION ABOUT MONDAY NIGHT. GFS
BRINGS A THIRD INTO THE GREAT BASIN TOWARD THU...BUT THE 12Z ECMWF
DEVELOPS THIS INTO A CLOSED LOW ALONG THE WEST COAST. WITH MODEL
INCONSISTENCIES NEXT WEEK...USED THE CONSENSUS MODEL FOR A RATHER
BROAD BRUSH AND VARYING CHANCE OF PRECIPITATION FOR MAINLY THE MTNS
NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 859 PM MST THU DEC 6 2012
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH FRIDAY NIGHT.
OROGRAPHIC LOW AND MID CLOUD WILL STILL REMAIN TRAPPED AGAINST
WEST-FACING SLOPES TONIGHT...PRODUCING AREAS OF MOUNTAIN
OBSCURATION...MVFR CIGS AND VSBYS IN SHOWERS AND LOCAL IFR CIGS
AND VSBYS IN THE MOUNTAINS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...15
LONG TERM...JAD
AVIATION...CC
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1135 PM CST THU DEC 6 2012
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
WEAK SHORTWAVE WILL CONTINUE TO PUSH EAST OF THE FORECAST AREA LATE
THIS AFTERNOON INTO THE EARLY EVENING WHILE A SECOND SHORTWAVE WILL
MOVE ACROSS SOUTHERN IOWA/NORTHERN MISSOURI THROUGH 09Z FRIDAY.
WEAK BOUNDARY ASSOCIATED WITH THE FIRST SHORTWAVE LOOKS TO BE INTO
NORTHERN MISSOURI AND FAR SOUTHEAST IOWA BY 00Z FRIDAY. SLIGHTLY
BETTER FORCING WITH THE SECOND VORT MAX LOOKS TO BE CONFINED TO
SOUTHEAST IOWA. THIS IS EVIDENT ALONG THE 295K TO 305K ISENTROPIC
SURFACE WHICH COINCIDES TO THE WEAK THETA-E ADVECTION AOA 700MB.
BUFR SOUNDINGS SATURATED ABOVE 700MB SO PRECIP WILL BE HIGH BASED
THIS EVENING. THE HI-RES MODELS RUNS OF THE NMM/ARW WRF AND HRRR ARE
IN GOOD AGREEMENT WITH SOME LIGHT PRECIP OVER THE SOUTH THROUGH 09Z
FRIDAY AND INCREASED POPS TO LIKELIES THROUGH 06Z IN THIS AREA.
THE WRF SIMULATED GOES-R PRODUCTS ARE DEPICTING A CLEAR SLOT MOVING
INTO CENTRAL IOWA FROM WEST TO EAST LATE TONIGHT INTO THE OVERNIGHT
HOURS AND SOMEWHAT AGREE THERE SHOULD BE A BRIEF PERIOD OF CLEAR
SKIES B/T 03-09Z. HOWEVER...THE SIMULATED PRODUCTS DO NOT HAVE A
GOOD HANDLE ON CURRENT SATELLITE TRENDS WRT TO HIGHER CLOUDS IN
NORTHWEST IOWA. SO DID NOT GO COMPLETELY CLEAR IN THE NORTH WITH
ANOTHER WAVE MOVING INTO NORTHERN IOWA FRIDAY. LEANED TOWARD THE
COOLER NAM12 FOR LOWS TONIGHT IN NORTHERN IOWA AND THE NISH
VALLEY...THEN CLOSER TO THE GFS ACROSS THE SOUTHEAST.
.LONG TERM /FRIDAY THROUGH THURSDAY/...
MORE WRINKLES FOR THE WEEKEND EVENT...THOUGH SOME CONSENSUS
BEGINNING TO SHOW UP REGARDING PREFERRED SOLUTION AND FORECAST.
FIRST OF ALL THE SYSTEM ON FRIDAY APPEARS TO BE GRAZING THE FAR
NORTH WITH SOME LIGHT SNOW AS MORE OF THE FORCING IN THE PAST TWO
RUNS WILL OCCUR OVER SOUTHERN MINNESOTA...WITH JUST SOME LIGHT
PRECIPITATION REACHING THE FAR NORTHERN COUNTIES OF THE FORECAST
AREA AS THE SYSTEM PASSES TO THE EAST. THIS WILL LIMIT ANY SNOWFALL
ACCUMULATIONS TO AN INCH OR LESS WITH THE FIRST WAVE DROPPING EAST
SOUTHEAST WITH TIME TOMORROW. ONE OF THE WRINKLES IN THE UPCOMING
FORECAST HAS BEEN A SHIFT TO LESS COLD AIR ARRIVING IN THE NEXT 48
HOURS AHEAD OF THE LATE WEEKEND WAVES. THIS WILL MODERATE BOTH
HIGHS AND LOWS...RESULTING IN A SLIGHTLY LONGER CHANGEOVER FROM
LIQUID TO FROZEN PRECIPITATION ON SUNDAY. THIS IS MAINLY DUE TO THE
LACK OF UPPER LEVEL ENERGY PHASING WHICH KEEPS THE NORTHERN STREAM
SHORT WAVE STRONGER AND THE COLD AIR FROM DRIVING SOUTH BEHIND THE
SYSTEM FAST ENOUGH TO INTERACT WITH THE SOUTHERN STREAM. THUS...WITH
LITTLE COLD AIR ADVECTION IN THE OFFING UNTIL THE STORM PASSES TO
THE EAST SUNDAY EVENING...THERE WILL BE LITTLE AMPLIFICATION OF THE
ENTIRE SYSTEM AND LESSER AMOUNTS OF FORCING...QPF...AND SNOWFALL
PRODUCTION OVER THE FORECAST AREA. NEVER THE LESS...SOME
ACCUMULATION IS EXPECTED AS THE TIMING OVER THE NORTH FAVORS A
QUICKER CHANGEOVER COMPARED TO THE SOUTH. WITH CONTINUED UNCERTAINTY
IN BOTH TIMING AND AREAL COVERAGE OF PRECIPITATION OVER THE RANGE OF
MODEL SOLUTIONS... HAVE OPTED TO LEAN TOWARD A MANUAL BLEND OF THE
EURO/NAM/GEM WITH LESS EMPHASIS ON THE GFS WHICH HAS DONE A COMPLETE
REVERSAL SINCE YESTERDAY. THE ONLY TREND IN THE MODELS NOW IS LITTLE
TO NO PHASING OF THE NORTHERN AND SOUTHERN STREAMS AND SLIGHTLY
WARMER TEMPS AS PREVIOUSLY MENTIONED. THUS...SOME LIGHT SNOW WITH A
POTENTIAL FOR A BRIEF PERIOD OF HEAVIER RAIN OR SNOW SATURDAY NIGHT
LATE NORTHEAST IS EXPECTED AS THE SYSTEM ROLLS ON THROUGH. SUNDAY
FOR THE MOST PART WILL EXPERIENCE FALLING TEMPERATURES WITH LESS
INTENSE PRECIPITATION. LIGHT ACCUMULATIONS OF SNOW WILL OCCUR BOTH
SATURDAY NIGHT AND SUNDAY OVER THE FORECAST AREA AND AMOUNTS WILL
RANGE FROM NEAR ONE HALF INCH IN THE SOUTH TO NEARLY 1.5 TO 2 INCHES
IN THE NORTHEAST. THOUGH THE COLD AIR FINALLY ARRIVES BY SUNDAY
NIGHT AND MONDAY...SOME MODERATION IS ALREADY EXPECTED TO OCCUR BY
TUESDAY THROUGH THURSDAY WHEN HIGHS REACH THE 30S TO LOWER 40S OVER
THE REGION SO WHAT SNOW DOES FALL THIS WEEKEND WILL SLOWLY DISAPPEAR
TOWARD NEXT THURSDAY. LITTLE TO NO PRECIPITATION WILL OCCUR AFTER
THE STORM SUNDAY...SO THE BALANCE OF THE EXTENDED FORECAST LOOKS
DRY.
&&
.AVIATION...07/06Z
-RA ASSOCIATED WITH WEAK BOUNDARY WILL QUICKLY PUSH OUT OF
KOTM...WITH VFR CEILINGS THROUGH PERIOD...THOUGH LOW VFR CEILINGS
WILL PUSH IN TOWARDS END OF PERIOD. A WAVE PUSHING ACROSS THE NORTH
WILL BRING PRECIPITATION CHANCES TO NORTHERN SITES KMCW/KALO LATE IN
PERIOD...ALONG WITH POSSIBLE MVFR CEILINGS. HAVE NOT INCLUDED
MENTION ATTM WITH UNCERTAINTIES.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
436 AM EST FRI DEC 7 2012
.SYNOPSIS...
A STATIONARY FRONT DRAPED OVER THE OHIO VALLEY WILL BE THE FOCUS
FOR PERIODIC RAIN INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RAIN CONTINUES TO MOVE EASTWARD ALONG FRONTAL BOUNDARY WHICH IS
DRAPED OVER THE UPPER OHIO VALLEY. RAIN IS DEVELOPING ALONG THE
SFC BOUNDARY...BUT AHEAD OF AN UPPER LEVEL WAVE WHICH WILL MOVE
THROUGH W PA THIS MORNING. ADDITIONALLY...A LOW LEVEL JET HAS
DEVELOPED TO THE SOUTH OF THE FRONT AND WILL CONTINUE TO PUMP
MOISTURE NORTHWARD INTO THE BOUNDARY.
EVEN AT THIS POINT...THERE STILL REMAIN DIFFERENCES IN MODEL
SOLUTIONS WITH THE POSITION OF THE FRONT AND WHEN AND WHERE THE
RAIN WILL FALL. WILL FIND COMMON GROUND AND STICK CLOSE TO 21Z
SREF...WHICH IS PROVIDING A "HAPPY MEDIUM" BETWEEN THE DIFFERING
SOLUTIONS.
THERE WILL BE A SERIES OF UPPER LEVEL WAVES THAT WILL MOVE THROUGH
TODAY...KEEPING WIDESPREAD SHOWERS IN THE FORECAST.
WITH THE SURGE OF WARMER AIR IN THE LOWEST LEVELS...TEMPS ACROSS
MUCH OF THE REGION WILL BE ABOVE NORMAL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
MILD AND WET WEA WL DOMINATE THE SHORT TERM PD AS A SERIES OF
DISTURBANCES TRIGGER WARM...MOIST ADVCTN AND PCPN AS THEY MOVE
ALONG A NEAR-STATIONARY FRONT PROJECTED OVR THE UPR OH VALLEY REGION.
BREAKS IN THE PCPN CAN BE EXPECTED WITH PASSAGE OF THE INDIVIDUAL
SHORTWAVES.
WARM TEMPS WERE FORECAST USING A MIX OF SREF/MAV NUMBERS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
CLOUDS AND WET WEATHER CONTINUE INTO EARLY NEXT WEEK. SHORTWAVE
THAT IS PROJECTED ACRS THE GREAT LAKES ON MONDAY INTO TUESDAY IS
FORECAST TO PUSH THE FRONT SUFFICIENTLY EWD TO END THE WET SPELL.
COLD ADVCTN IN THE WAKE OF THE FRONT WITH UPSLOPE/LAKE ENHANCEMENT
MAY SPPRT SOME SNOW SHOWERS FOR TUE AND TUE NGT...BUT DO NOT
FORESEE MUCH ACCUM AT THIS JUNCTURE AS THE MAGNITUDE AND DEPTH OF
THE COLD POOL RMNS QNABLE.
SEASONAL TEMPERATURES AND DRY WX ARE EXPECTED TO QUICKLY RTN THOUGH
AS SW FLOW RESUMES WED AND CONTS THROUGH THE BALANCE OF THE
PERIOD.
&&
.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
RECENT RADAR AND SURFACE DATA...COUPLED WITH RECENT RAP AND WRF-
NMM MODEL OUTPUT...SHOWS THE INITIAL SURGE OF RAIN ALONG THE
DEVELOPING STATIONARY FRONT NEAR THE I-70 CORRIDOR WILL CONTINUE
TO SPREAD NORTHEASTWARD ACROSS THE UPPER OHIO VALLEY. THIS HAS
CAUSED CONDITIONS TO LOWER TO MAINLY MVFR. AS SURFACE LAYER
SATURATES..CONDITIONS WILL LOWER TO MAINLY IFR BY 14Z.
WRF-NMM AND SREF MODEL OUTPUT SHOW THERE WILL BE ADDITIONAL SURGES
OF IFR RAIN TONIGHT AND SATURDAY...AS LOW PRESSURE WAVES MOVE
EASTWARD ALONG THE STATIONARY FRONT.
SURFACE WINDS WILL BE MAINLY FROM THE SOUTH AT NO MORE THAN 10
KTS.
.OUTLOOK.../SATURDAY NIGHT THROUGH TUESDAY/...
FREQUENT IFR RESTRICTIONS DUE TO RAIN FOG AND STRATUS WILL CONTINUE
INTO TUESDAY DUE TO A SERIES OF LOW PRESSURE SYSTEMS MOVING EASTWARD
ALONG THE STALLED FRONT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1100 PM CST THU DEC 6 2012
.UPDATE...
06Z AVIATION DISCUSSION ADDED BELOW.
&&
.PREV DISCUSSION...
/ISSUED 417 PM CST THU DEC 6 2012/
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT.
ZONAL FLOW ACROSS MOST OF THE CONUS HAS LED TO RELATIVELY TRANQUIL
WEATHER TODAY...ASIDE FROM A COLD FRONT MOVING ACROSS WRN WI THIS
AFTERNOON. THE COLD FRONT IS ASSOCIATED WITH LOW PRESSURE OVER
HUDSON BAY WHICH IS PUSHING NORTHEAST FAIRLY RAPIDLY. LOTS OF
CLOUDS ARE EMBEDDED WITHIN THE WESTERLY FLOW SO NOT ANTICIPATING
THE CLEARING CURRENTLY OVER SRN MN TO LAST MUCH BEYOND EARLY
EVENING...ESPECIALLY WITH THE NEXT SHORT WAVE CURRENTLY OVER
NORTHWESTERN WASHINGTON STATE MOVING INTO THE NORTHERN PLAINS BY
EARLY FRIDAY MORNING. KEPT TEMPS A TOUCH ABOVE MOS CONSENSUS WITH
LOWS GENERALLY IN THE LOW TO MID 20S.
THE SHORT WAVE WILL CONTINUE HEADING EAST FRIDAY...BUT IT WON/T
BEGIN TO REALLY AFFECT THE AREA UNTIL FRIDAY AFTERNOON. MODELS
CONTINUE TO SHOW THIS FEATURE WEAKENING AS IT PUSHES INTO SRN
MN...WITH QPF RANGING FROM 0.15 INCHES NEAR REDWOOD FALLS TO
LESS THAN 0.05 INCHES OVER WRN WI. GOOD LIFT ARRIVES FAIRLY
EARLY...BUT CONSIDERABLE DRY AIR IN THE BOUNDARY LAYER WILL
INHIBIT MUCH SNOW FROM REACHING THE GROUND UNTIL AFTER 18Z IN SWRN
MN AND AFTER 21-00Z ACROSS ERN MN AND FAR WRN WI. THE BEST OVERLAP
OF THESE TWO CRITICAL ELEMENTS WILL LAST ABOUT 6 HOURS OVER WRN MN
BUT WEAKENING LIFT WITH TIME WILL LEAVE THE EAST /INCLUDING THE
TWIN CITIES METRO/ WITH A FEW HOUR WINDOW. UNFORTUNATELY THIS
COMES DURING RUSH HOUR...BETWEEN 23-02Z. TOTAL SNOWFALL AMOUNTS
WITH THIS FEATURE WILL RANGE FROM 1 TO 2 INCHES ACROSS SWRN MN...TO
UP TO ONE HALF INCH NORTHEAST OF A LINE FROM ALEXANDRIA...
HUTCHINSON...AND MANKATO. AS THIS IS BEING WRITTEN...THE 18Z GFS
CAME IN WITH MUCH HIGHER QPF AND 0.15 INCHES NOW EXTENDS NORTH TO
AXN/STC/RNH. WHILE THIS RUN IS AN OUTLIER...TRENDS WILL NEED TO BE
MONITORED FOR LATER FORECASTS.
THAT SHORT WAVE WILL DISSIPATE FRIDAY EVENING WITH DRY CONDITIONS
EXPECTED LATE FRIDAY NIGHT AS HIGH RH IS LOST IN THE DGZ LAYER AND
ABOVE.
LONG TERM...SATURDAY THROUGH THURSDAY.
THE BETTER SYSTEM OF THE TWO STILL LOOKS LIKE IT WILL IMPACT THE
AREA SATURDAY AFTERNOON THROUGH SUNDAY...BUT PRECISE DETAILS ARE
FAR FROM CERTAIN. MODELS HAVE...HOWEVER...COME INTO BETTER
AGREEMENT WITH THE OVERALL EVOLUTION OF THIS STORM FROM PREVIOUS
RUNS. AS A 160 KT UPPER JET DIVES DOWN THE WESTERN ROCKIES...A MID
LEVEL DISTURBANCE WILL EJECT EASTWARD ACROSS CENTRAL MINNESOTA
SATURDAY EVENING. IT WILL REMAIN LARGELY DETACHED FROM ANOTHER
DISTURBANCE HANGING BACK IN THE DEEP TROUGH OVER THE FOUR CORNERS ON
SUNDAY AFTERNOON...SO AN IMPRESSIVE WINTER STORM IS NOT ANTICIPATED
BUT ACCUMULATING SNOW IS STILL FORECAST...ESPECIALLY OVER ERN/CNTRL
MN AND WRN WI.
DECENT ISENTROPIC LIFT IS STILL BEING SEEN ON THE 285 AND 290K
SURFACES EARLY SATURDAY AFTERNOON OVER WRN MN WHICH WILL SPREAD
EASTWARD SATURDAY NIGHT. THIS LIFT SHOULD PRODUCE A BAND OF SNOW
THAT WILL PROPAGATE ACROSS THE AREA FROM WEST TO EAST SATURDAY
AFTERNOON INTO SUNDAY. BETTER LIFT AND HIGHER MOISTURE CONTENT
WITH THIS SYSTEM SHOULD OVERCOME DRY AIR IN THE BOUNDARY LAYER
FAIRLY QUICKLY...WITH MODERATE TO HEAVY SNOWFALL RATES POSSIBLE
SIMILAR TO THE THANKSGIVING SYSTEM. INTENSITY WILL MAKE UP FOR THE
DURATION WHICH IS ONLY EXPECTED TO BE ABOUT 6-12 HOURS...EXCEPT OVER
WRN WI WHERE IT MAY LINGER A BIT LONGER. MID LEVEL DRY SLOT PUNCHING
IN FROM THE SOUTHWEST BEHIND THE LOW WILL CLEAR OUT ANY STEADY SNOW
LATE SATURDAY NIGHT AND SUNDAY MORNING ACROSS CENTRAL AND WESTERN
MN. THE DRY SLOT SHOULD REACH WRN WI BY SUNDAY AFTERNOON. WRAP
AROUND SNOW SHOWERS COULD DROP DOWN ALONG THE ARCTIC COLD FRONT
SUNDAY AFTERNOON.
TAKING AN AVERAGE OF QPF FROM THE MODELS BRINGS BETWEEN A TENTH
AND A THIRD OF AN INCH...MOST BEING ACROSS WRN WI AND LEAST ACROSS
SWRN MN. USING ROUGHLY A 13:1 RATIO /POSSIBLY LOWER IF THE NAM BL
TEMPS IN THE MID/UPPER 30S VERIFY/ WOULD BRING AN INCH ACROSS SWRN
MN...ABOUT 2 INCHES IN THE TC METRO...AND 3 TO 4 INCHES OVER WRN
WI. USING THE GARCIA METHOD OF DOUBLING THE AVERAGE MIXING RATIO
OVER A 12 HR PERIOD WOULD RESULT IN 4-5 INCHES OF SNOW...BUT CUTTING
THAT IN HALF FOR A 6-HR DURATION BRINGS ABOUT 2 INCHES WHICH MATCHES
THE CURRENT THINKING.
BEHIND THE ARCTIC FRONT...THE FIRST REAL TASTE OF WINTER WILL
ARRIVE ON SUSTAINED 20 KT WINDS...WITH SOME GUSTS TO 30 KTS OVER
WRN MN SUNDAY AFTERNOON. DEPENDING ON THE QUALITY OF THE
SNOW...COULD SEE SOME BLOWING AND DRIFTING SUNDAY AFTERNOON.
TEMPERATURES WILL PLUMMET FROM THE 20S AND 30S TO THE SINGLE
DIGITS NORTHWEST AND LOWER 20S IN WRN WI BY EARLY EVENING WITH
WIND CHILL READINGS AS LOW AS 15 BELOW NEAR THE SD BORDER. WHILE
WINDS WILL SUBSIDE A BIT SUNDAY NIGHT...HIGH PRESSURE BUILDING IN
AND TEMPERATURES FALLING INTO THE -3 TO +11 RANGE WILL BRING
SUBZERO WC READINGS EVERYWHERE...BUT COULD APPROACH WIND CHILL
ADVY CRITERIA /-20 TO -25F/ OVER WRN AND CNTRL MN IF WIND SPEEDS
REMAIN ABOVE 10 KTS.
AFTER A COLD DAY MONDAY...A MILDER AIRMASS WILL RETURN FOR MIDWEEK
AS A SERIES OF WEATHER SYSTEMS TRAVERSE THE FAR NORTHERN CONUS. AT
THIS POINT...THE BEST CHANCES FOR ACCUMULATING SNOW WILL REMAIN
NORTH OF THE CWA.
&&
.AVIATION.../06Z TAF ISSUANCE/
MAIN CHANGE WITH 06Z TAFS...IS THAT 00Z NAM/GFS ALONG WITH LAST
FEW RUNS OF THE HRRR IS STARTING TO INCREASE CONFIDENCE IN -SN
OCCURRING AT ALL TERMINALS. TIMING IN TAFS STILL LOOKS GOOD AS WELL.
GFS/NAM ALONG WITH THE HRRR SEEM TO BE HONING IN ON A BAND OF -SN
COMING OUT OF CENTRAL SODAK...THEN DUE EAST ACROSS THE MPX AREA FRI
AFTERNOON/EVENING. AXN/STC MAY BE JUST NORTH OF THE HEAVIEST
SNOW...BUT A QUICK 1-3 INCHES IS LOOKING MORE PLAUSIBLE FOR RWF
AND MSP. FOR WI...MODELS CONTINUE TO SHOW FORCING AND SNOW WANING
AS THINGS GET INTO WI...SO LEFT VIS RESTRICTIONS ANT RNH/EAU AT
MVFR. CIGS WILL BE SLOW TO DESCEND...BUT BY FRIDAY NIGHT...925-850
RH FROM THE GFS/NAM ALONG WITH SREF PROBS FOR CIGS LESS THAN 3K FT
WOULD INDICATE THAT A BAND OF IFR/MVFR MAY GET HUNG UP ACROSS
MN...SO DID TREND CIGS DOWNWARD...ESPECIALLY FOR AXN/RWF.
KMSP...290/295K ISENTROPIC SFCS ALONG WITH MID-LEVEL FGEN WOULD
SAY SNOW COULD START AS EARLY AS 18Z AT MSP...BUT BEST FORCING
STILL WAITS UNTIL 00Z TO BRING IN BEST FORCING...SO BROUGHT IN IFR
VSBYS THEN. LOOKS LIKE THE EVENING RUSH COULD SEE 1-3 INCHES OF
SNOW IF CURRENT GFS/NAM PANS OUT. FOR WINDS...THEY WILL BE LIGHT
WITH HIGH PRESSURE SLIDING BY THROUGH THE PERIOD WITH JUST A
GRADUAL VEERING OF WINDS FROM NW TO SE THROUGH THE PERIOD.
DIRECTIONS LOOK TO CROSS AN 040 DIRECTION AROUND 3Z.
/OUTLOOK FOR KMSP/
SAT...MVFR CIGS ENDING MID MORNING...THEN VFR. MVFR/IFR CIGS/VIS
DEVELOPING OVERNIGHT WITH SN. WINDS SE AT 10KTS.
SUN...SN ENDING IN MORNING...1-3 IN POSSIBLE. MVFR/IFR CIGS/VIS IN
MORNING. MVFR CIGS AFTERNOON. WINDS BCMG NW 20G30KTS.
MON...MVFR CIGS EARLY...BECOMING VFR IN AFTERNOON. WINDS NW 15KTS
IN MORNING...BCMG SW AT 5 KTS IN AFTERNOON.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BORGHOFF/MPG
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1141 PM CST THU DEC 6 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Now appears after the fact that the 18z model runs were out to lunch
as far as the rain is concerned for tonight. 00z TOP raob was pretty
dry below 700mb except for the small layer of moisture around 850mb.
00z NAM and RAP are much much drier and barely eke out any qpf
overnight. Best chance for light rain this evening will be across
far northern MO and even then that area doesn`t look to promising.
After midnight some light rain or sprinkles may try to form over
parts of west central and central MO as the moisture thickens around
850mb. Latest satellite data shows a weak mid level shortwave now in
far eastern KS and as it passes by it strips away the deeper
moisture and thus ends the threat of rain. Appears the upper jet
dynamics associated with the southern stream don`t trump the lack of
decent moisture.
Bottom-line is need to lower pops and even where slight chance pops
remain it may be more of a case of a few sprinkles. Otherwise, no
major changes made to any of the other elements.
MJ
&&
.PREV DISCUSSION...
Short Term (Tonight and Friday)...
In the near term, the primary forecast concern will be precipitation
chances for tonight through midday Friday. Pacific midlevel moisture
streaming through the Plains states has combined with a small amount
of energy ejecting out of the semi-permanent lee-side trough feature
over the southern High Plains to create light showers across
portions of eastern Nebraska, eastern Kansas, western Missouri, and
Iowa this afternoon. However, dry near-surface conditions has led to
a large amount of evaporation below cloud base, keeping the amount of
rain that reaches the surface nominal. Forcing for precipitation from
the southern shortwave trough looks strongest across the majority of
the forecast area in the 03z-09z time frame, while relative low-level
moisture also increases, slightly increasing the chance for any
measurable precipitation. The overall chance of showers remains low
through the period, but occurs over an extended period of time from
this afternoon through Friday afternoon as the southern jet slowly
drops southeast. Rain chances associated with this system should end
altogether sometime late Friday afternoon or evening.
Fairly extensive cloud cover should keep high temperatures muted
throughout the period (albeit above normal), and low temperatures
mild. The only exception will be over the northwest on Friday night,
as clouds gradually clear and temperatures begin to drop.
Laflin
Long Term (Saturday-Thursday)...
Consistency among forecast model guidance has increased over the
last couple of runs with forecast confidence also increasing with
regards to weekend precipitation chances. Forecast confidence
remains high for significant cooler weather Sunday into early next
week before temperatures begin to moderate the middle of next week.
Strong shortwave energy moving through the Pacific Northwest into
the Central Rockies will deepen a broad upper trough in the Plains
and the Ohio Valley. In response to height falls aloft, surface low
pressure is progged to develop across the Northern Plains and track
through the upper Midwest with the potential of another surface low
to move through the Southern Plains into the Lower and Middle
Mississippi Valley. An associated strong cold front will move
through the Plains entering Northwest Missouri early Sunday morning.
Strong cold air advection behind the front will likely produce
falling temperatures Sunday afternoon.
Precipitation amounts are expected to remain light. Initially
precipitation will be driven by warm air advection and moisture
transport processes ahead of the frontogenetic forcing. Due to the
progressive movement of the upper trough...only shallow moisture
return is anticipated in Northeast Kansas and Northwest Missouri
with deeper moisture return occurring across the Lower and Middle
Mississippi River Valley. Thus have continued with precipitation
amounts generally less than a quarter of an inch. While light snow
will be possible post frontal passage, drier air will rapidly advect
into the dendritic zone. This drier air intrusion along with low
snowfall rates and warm ground temperatures from the recent above
normal temperatures will limit any accumulation to around a half
inch or less where snow occurs.
Below normal temperatures are likely Monday and Tuesday before
temperatures begin to rebound with high pressure building east and
southerly return flow developing with a lee side trough in the High
Plains.
Angle
&&
.AVIATION...
For the 06z TAFs, rain chances have decreased considerably for the
overnight hours as a shortwave trough moves east across the MO/KS
state line. Earlier models were overly generous on saturating a deep
layer of the atmosphere. 00z TOP raob was dry below 700mb and latest
model runs/radar trends now confirm a basically dry forecast.
Main concern is how long will MVFR cigs last. NEF analysis shows
MVFR cigs forming over south central IA and trajectories will likely
advect this moisture into the terminals overnight. This supports the
00z Bufr soundings so will maintain MVFR cigs until at least mid
morning Friday. Should see drier air gradually work in from the
north and allow cigs to rise to low end VFR by late morning or early
afternoon...eventually scattering out by late in the day.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
444 AM EST FRI DEC 7 2012
.SYNOPSIS...
AN APPROACHING WARM FRONT WILL LEAD TO SCATTERED SHOWERS ACROSS
THE REGION TODAY. THIS WILL MARK THE BEGINNING OF A RATHER
UNSETTLED PERIOD WITH SCATTERED SHOWERS POSSIBLE EACH DAY AS
SEVERAL DISTURBANCES INTERACT WITH THE STALLED FRONT. TEMPERATURES
THROUGH THE WEEKEND WILL REMAIN ABOVE NORMAL AS ANY COLD AIR
REMAINS DISPLACED WELL TO OUR WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MAIN CONCERN IN THE NEAR TERM CONTINUES TO BE APPROACHING FRONTAL
WAVE AND ASSOCIATED PRECIP LATER THIS MORNING. LATEST REGIONAL
RADAR IMAGES SHOWING LEADING EDGE OF RAIN NOW EAST OF PIT AND
WORKING TOWARDS JST IN SW PA. AHEAD OF THIS PRECIP...A SUBSTANTIAL
AMOUNT OF DRY AIR REMAINS IN PLACE AS EVIDENCED BY 00Z PIT AND BUF
RAOBS. PRECIP IS BEING FORCED LARGELY BY ISENTROPIC ASCENT ALONG
THE 285-295 THETA SURFACES AS INCREASING WINDS AT THE 925 AND
850-MB LEVELS ASCEND THE APPROACHING FRONTAL BOUNDARY. WITH THE
AMOUNT OF DRY AIR IN PLACE...HAVE ELECTED TO TRIM BACK TIMING OF
PRECIP ARRIVAL TIME FROM THE TWIN TIERS AND POINTS SOUTH. IT NOW
APPEARS THAT PRECIP WILL NOT MAKE INTO THE CWA BEFORE 12Z AS
SUFFICIENT TIME WILL BE REQUIRED TO MOISTEN THE ATMOSPHERIC
COLUMN.
THE ABOVE SAID...MAIN ATTENTION CONTINUES TO FOCUS ON FZRA
POTENTIAL AS INITIAL BATCH OF PRECIP MOVES IN. CLOSE INSPECTION OF
BOTH RR AND WRF THETA SURFACES AND MODEL CONDENSATION PRESSURE
DEFICITS REVEALS APPROPRIATE SATURATION ALONG THE 285 SFC WILL NOT
OCCUR UNTIL 13Z AT THE EARLIEST. BY THIS TIME...DIURNAL TEMPS
SHOULD BEGIN REBOUNDING AS DAYTIME HEATING COMMENCES WHICH SHOULD
ONLY RESULT IN A VERY BRIEF PERIOD WHERE SFC TEMPS MAY BE COLD
ENOUGH TO SUPPORT FZRA ALONG THE ELEVATED SURFACES OF THE NORTHERN
TIER AND LOWER WYOMING VALLEY REGIONS OF NE PA. CONSIDERING THAT
ANY FZRA WILL BE VERY SHORTLIVED...ALONG WITH THE FACT THAT
OVERALL CONFIDENCE REMAINS BELOW 25%...HAVE ELECTED FOR FORGO ANY
WINTER WX HEADLINES FOR THE TIME BEING. IF TRENDS SUGGEST A BETTER
POTENTIAL FOR FREEZING PRECIP IN THE COMING HRS...A QUICK WSW
STATEMENT OR SPS CAN BE ISSUED AS NEEDED. HOWEVER WITH SUCH DRY
AIR IN PLACE AHEAD OF THE FRONT AND LATER ARRIVAL
TIME...CONFIDENCE IS JUST NOT HIGH ENOUGH TO WARRANT ANY HEADLINES
ATTM.
BEYOND THIS...RA WILL GRADUALLY OVERSPREAD THE REGION THROUGH THE
MORNING AND AFTERNOON HRS. UP NORTH...PRECIP WILL LIKELY HOLD OFF
UNTIL EARLY AFTERNOON AFTER WHICH...WEAK SHORTWAVE ENERGY RIDING
ALONG THE FRONT SHOULD EVENTUALLY ALLOW PRECIP TO EXTEND AS FAR
NORTH AS THE SYR AND RME AREAS. RAINFALL AMOUNTS THROUGH THE DAY WILL
LIKELY REMAIN UNDER 2 TENTH OF AN INCH AT MOST LOCATIONS...WITH
EVEN LOWER AMOUNTS EXPECTED ACROSS THE NORTHERN FINGER LAKES AND
WESTERN MOHAWK VALLEY AS MAX FRONTAL FORCING REMAINS SOUTH. HIGH
TEMPS WILL TOP OUT IN LOWER 40S ACROSS THE NORTHERN FINGER LAKES
AND LAKE PLAIN...WITH MIDDLE TO UPPER 30S DOMINATE ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
FAIRLY ACTIVE PERIOD CONTINUING TO TAKE SHAPE THROUGH THE UPCOMING
WEEKEND AS THE NEXT IN A SERIES OF SFC LOWS LIFTS NORTH ALONG A
STALLED FRONT TO OUR WEST BEGINNING TONIGHT. THAT SAID...RA ACROSS
THE REGION SHOULD BECOME A LITTLE BIT MORE ORGANIZED INITIALLY
THIS EVENING AS SFC LOW LIFTS NORTH FROM THE LWR OHIO VLY INTO THE
LWR GREAT LAKES. AS THIS OCCURS...FORCING CONTRIBUTIONS FROM BOTH
THE POLAR AND SUBTROPICAL JETS WILL TRANSCEND ACROSS THE REGION
WITH ADDITIONAL FORCING ARRIVING FROM CONTINUED ISENTROPIC ASCENT
ALONG THE PREVIOUSLY MENTIONED WARM FRONT. THERMAL PROFILES FROM
ACROSS THE REGION INDICATE SFC TEMPS WILL REMAIN ABOVE FREEZING AS
WARM AIR ADVECTION CONTINUES. THIS SHOULD KEEP ANY PRECIP IN
LIQUID FORM.
SFC LOW PROGGED TO PASS TO OUR WEST ON SATURDAY WITH INCREASING
SOUTHWESTERLY FLOW FINALLY ALLOWING WARM FRONT TO LIFT NORTH
THROUGH THE ENTIRE CWA. AS A RESULT...EXPECT A WARMER DAY WITH
TEMPS TOPPING OUT IN THE UPPER 40S TO LOWER 50S ACROSS MUCH OF THE
AREA. WITH BEST FORCING FOR ASCENT ARRIVING FROM A NORTHERN STREAM
SHORTWAVE ACROSS THE UPPER GREAT LAKES...BEST CHANCES FOR
ORGANIZED PRECIP WILL LIKELY REMAIN NORTH AND WEST OF OUR AREA.
DESPITE THIS HOWEVER...SHORT TERM MODELS INDICATE A DEVELOPING SECONDARY
LOW OFF THE NJ COAST THROUGH THE DAY WHICH COMBINED WITH A WEAKER
SHORTWAVE IMPULSE PASSING OVERHEAD SHOULD KEEP THE CHC FOR SHWRS
ACROSS THE AREA THROUGH THE DAY. MAIN LOW EXPECTED TO PASS TO OUR
NORTH OVERNIGHT WHICH WILL SEND A COLD FRONT SOUTH ACROSS THE FCST
AREA. MODELS AGREE A QUICK COOL DOWN WILL OCCUR AFTER PASSAGE WITH
850-MB TEMPS QUICKLY FALLING TO -4C ACROSS THE FAR NORTH. HIGHLY
SHEARED FLOW COMBINED WITH THE INFLUX OF DRY AIR AND ONLY MARGINAL
TEMP DIFFERENCES WILL NEGATE ANY LAKE RESPONSE AND THUS HAVE DRIED
THINGS OUT FROM NORTH TO SOUTH OVERNIGHT EARLY SUN.
NEXT MORE POTENT WAVE TO LIFT NORTH FROM THE OHIO VLY ON SUN WHICH
WILL ONCE AGAIN LIFT THE FRONT BACK NORTH THROUGH BEGINNING SUN
NGT. AS SUCH...EXPECT INCREASING CHANCES FOR RAIN ONCE AGAIN SUN
AFTERNOON AND EVENING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
430 AM UPDATE...
NO CHGS NEEDED TO LONG TERM AT THIS TIME AS FRONT MVS THRU MON
EVNG WITH LKLY RAIN SHOWERS. NW FLOW KICKS IN FOLLOWING FROPA TO RESULT
IN LK EFFECT PCPN. BOTH 12Z AND NOW 00Z EC INDICATE DVLPNG SFC
LOPRES RIDING UP ALONG SFC BNDRY JUST OFF THE EAST COAST BY EARLY
WEEK, ALTHO NO OTHER MED RANGE MODELS HV THIS FEATURE.
PREV DISCUSSION BLO...
MEDIUM RANGE MODELS CONTINUE TO SHOW FAIR AGREEMENT THROUGH THE
EXTENDED PERIOD.
SUNDAY NIGHT THROUGH MONDAY, SFC LOW PRES WILL TRACK FROM THE OHIO
VALLEY NORTHEAST ACROSS LAKE ERIE INTO NEARBY SOUTHERN ONTARIO.
WILL CARRY LIKELY POPS BOTH PERIODS WITH RAIN LIKELY SUNDAY NIGHT
FOLLOWED BY RAIN SHOWERS ON MONDAY AS TRAILING COLD FRONT CROSSES
AREA MONDAY AFTERNOON AND EVENING. THROUGH MONDAY EVENING TEMPS
WILL REMAIN WARM ENOUGH FOR JUST LIQUID PRECIP TO FALL. MONDAY
NIGHT AS TEMPS LOWER UNDER CAA AND NORTHWEST FLOW, A WEAK LAKE
RESPONSE MAY OCCUR INTO TUESDAY.
TUESDAY NIGHT THROUGH THURSDAY, LOOKS DRY WITH SFC HIGH PRES
STRETCHING FROM THE MID ATLANTIC REGION INTO NEW ENGLAND.
TEMPS THROUGH THE PERIOD WILL START WELL ABOVE NORMAL THEN FALL TO
SEASONAL LEVELS TUESDAY AND WEDNESDAY BEFORE MODERATING AGAIN ON
THURSDAY.
&&
.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
VFR EXPECTED THROUGH LATE MORNING/EARLY AFTERNOON BEFORE RAIN AND
LOW CLOUDS BEGIN TO APPROACH FROM THE SOUTHWEST. LIGHT RAIN WILL
MOVE INTO PA TERMINALS BY 15Z THEN NORTH INTO KELM BY 16Z, KBGM BY
17Z, AND KITH BY 18Z. SIGNIFICANT DRY AIR WILL BE IN PLACE ACROSS
NORTHERN SITES WHERE RAIN WILL NOT MOVE IN UNTIL AFTER 00Z. BY THE
TIME THE RAIN STARTS, SURFACE TEMPERATURES WILL LIKELY RISE ABOVE
FREEZING TO PREVENT FREEZING RAIN AT AREA TERMINALS TODAY.
MVFR CIGS WILL SPREAD INTO HIGHER ELEVATION TERMINALS (KBGM AND
KITH) AFTER 18Z WITH REMAINING TERMINALS DELAYED UNTIL AFTER 20Z.
SOUTHEAST WIND WILL SLOWLY COME AROUND TO A MORE SOUTHERLY
DIRECTION THIS AFTERNOON AROUND 10KTS.
OUTLOOK...
SATURDAY...MVFR IN SHRA.
SATURDAY NIGHT/SUNDAY MORNING...PRIMARILY VFR.
SUNDAY AFTERNOON THROUGH MONDAY EVENING...RESTRICTIONS EXPECTED IN
RAIN.
TUESDAY...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG
SHORT TERM...CMG
LONG TERM...PVN/RRM
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
421 AM EST FRI DEC 7 2012
.SYNOPSIS...
AN APPROACHING WARM FRONT WILL LEAD TO SCATTERED SHOWERS ACROSS
THE REGION TODAY. THIS WILL MARK THE BEGINNING OF A RATHER
UNSETTLED PERIOD WITH SCATTERED SHOWERS POSSIBLE EACH DAY AS
SEVERAL DISTURBANCES INTERACT WITH THE STALLED FRONT. TEMPERATURES
THROUGH THE WEEKEND WILL REMAIN ABOVE NORMAL AS ANY COLD AIR
REMAINS DISPLACED WELL TO OUR WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MAIN CONCERN IN THE NEAR TERM CONTINUES TO BE APPROACHING FRONTAL
WAVE AND ASSOCIATED PRECIP LATER THIS MORNING. LATEST REGIONAL
RADAR IMAGES SHOWING LEADING EDGE OF RAIN NOW EAST OF PIT AND
WORKING TOWARDS JST IN SW PA. AHEAD OF THIS PRECIP...A SUBSTANTIAL
AMOUNT OF DRY AIR REMAINS IN PLACE AS EVIDENCED BY 00Z PIT AND BUF
RAOBS. PRECIP IS BEING FORCED LARGELY BY ISENTROPIC ASCENT ALONG
THE 285-295 THETA SURFACES AS INCREASING WINDS AT THE 925 AND
850-MB LEVELS ASCEND THE APPROACHING FRONTAL BOUNDARY. WITH THE
AMOUNT OF DRY AIR IN PLACE...HAVE ELECTED TO TRIM BACK TIMING OF
PRECIP ARRIVAL TIME FROM THE TWIN TIERS AND POINTS SOUTH. IT NOW
APPEARS THAT PRECIP WILL NOT MAKE INTO THE CWA BEFORE 12Z AS
SUFFICIENT TIME WILL BE REQUIRED TO MOISTEN THE ATMOSPHERIC
COLUMN.
THE ABOVE SAID...MAIN ATTENTION CONTINUES TO FOCUS ON FZRA
POTENTIAL AS INITIAL BATCH OF PRECIP MOVES IN. CLOSE INSPECTION OF
BOTH RR AND WRF THETA SURFACES AND MODEL CONDENSATION PRESSURE
DEFICITS REVEALS APPROPRIATE SATURATION ALONG THE 285 SFC WILL NOT
OCCUR UNTIL 13Z AT THE EARLIEST. BY THIS TIME...DIURNAL TEMPS
SHOULD BEGIN REBOUNDING AS DAYTIME HEATING COMMENCES WHICH SHOULD
ONLY RESULT IN A VERY BRIEF PERIOD WHERE SFC TEMPS MAY BE COLD
ENOUGH TO SUPPORT FZRA ALONG THE ELEVATED SURFACES OF THE NORTHERN
TIER AND LOWER WYOMING VALLEY REGIONS OF NE PA. CONSIDERING THAT
ANY FZRA WILL BE VERY SHORTLIVED...ALONG WITH THE FACT THAT
OVERALL CONFIDENCE REMAINS BELOW 25%...HAVE ELECTED FOR FORGO ANY
WINTER WX HEADLINES FOR THE TIME BEING. IF TRENDS SUGGEST A BETTER
POTENTIAL FOR FREEZING PRECIP IN THE COMING HRS...A QUICK WSW
STATEMENT OR SPS CAN BE ISSUED AS NEEDED. HOWEVER WITH SUCH DRY
AIR IN PLACE AHEAD OF THE FRONT AND LATER ARRIVAL
TIME...CONFIDENCE IS JUST NOT HIGH ENOUGH TO WARRANT ANY HEADLINES
ATTM.
BEYOND THIS...RA WILL GRADUALLY OVERSPREAD THE REGION THROUGH THE
MORNING AND AFTERNOON HRS. UP NORTH...PRECIP WILL LIKELY HOLD OFF
UNTIL EARLY AFTERNOON AFTER WHICH...WEAK SHORTWAVE ENERGY RIDING
ALONG THE FRONT SHOULD EVENTUALLY ALLOW PRECIP TO EXTEND AS FAR
NORTH AS THE SYR AND RME AREAS. RAINFALL AMOUNTS THROUGH THE DAY WILL
LIKELY REMAIN UNDER 2 TENTH OF AN INCH AT MOST LOCATIONS...WITH
EVEN LOWER AMOUNTS EXPECTED ACROSS THE NORTHERN FINGER LAKES AND
WESTERN MOHAWK VALLEY AS MAX FRONTAL FORCING REMAINS SOUTH. HIGH
TEMPS WILL TOP OUT IN LOWER 40S ACROSS THE NORTHERN FINGER LAKES
AND LAKE PLAIN...WITH MIDDLE TO UPPER 30S DOMINATE ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
FAIRLY ACTIVE PERIOD CONTINUING TO TAKE SHAPE THROUGH THE UPCOMING
WEEKEND AS THE NEXT IN A SERIES OF SFC LOWS LIFTS NORTH ALONG A
STALLED FRONT TO OUR WEST BEGINNING TONIGHT. THAT SAID...RA ACROSS
THE REGION SHOULD BECOME A LITTLE BIT MORE ORGANIZED INITIALLY
THIS EVENING AS SFC LOW LIFTS NORTH FROM THE LWR OHIO VLY INTO THE
LWR GREAT LAKES. AS THIS OCCURS...FORCING CONTRIBUTIONS FROM BOTH
THE POLAR AND SUBTROPICAL JETS WILL TRANSCEND ACROSS THE REGION
WITH ADDITIONAL FORCING ARRIVING FROM CONTINUED ISENTROPIC ASCENT
ALONG THE PREVIOUSLY MENTIONED WARM FRONT. THERMAL PROFILES FROM
ACROSS THE REGION INDICATE SFC TEMPS WILL REMAIN ABOVE FREEZING AS
WARM AIR ADVECTION CONTINUES. THIS SHOULD KEEP ANY PRECIP IN
LIQUID FORM.
SFC LOW PROGGED TO PASS TO OUR WEST ON SATURDAY WITH INCREASING
SOUTHWESTERLY FLOW FINALLY ALLOWING WARM FRONT TO LIFT NORTH
THROUGH THE ENTIRE CWA. AS A RESULT...EXPECT A WARMER DAY WITH
TEMPS TOPPING OUT IN THE UPPER 40S TO LOWER 50S ACROSS MUCH OF THE
AREA. WITH BEST FORCING FOR ASCENT ARRIVING FROM A NORTHERN STREAM
SHORTWAVE ACROSS THE UPPER GREAT LAKES...BEST CHANCES FOR
ORGANIZED PRECIP WILL LIKELY REMAIN NORTH AND WEST OF OUR AREA.
DESPITE THIS HOWEVER...SHORT TERM MODELS INDICATE A DEVELOPING SECONDARY
LOW OFF THE NJ COAST THROUGH THE DAY WHICH COMBINED WITH A WEAKER
SHORTWAVE IMPULSE PASSING OVERHEAD SHOULD KEEP THE CHC FOR SHWRS
ACROSS THE AREA THROUGH THE DAY. MAIN LOW EXPECTED TO PASS TO OUR
NORTH OVERNIGHT WHICH WILL SEND A COLD FRONT SOUTH ACROSS THE FCST
AREA. MODELS AGREE A QUICK COOL DOWN WILL OCCUR AFTER PASSAGE WITH
850-MB TEMPS QUICKLY FALLING TO -4C ACROSS THE FAR NORTH. HIGHLY
SHEARED FLOW COMBINED WITH THE INFLUX OF DRY AIR AND ONLY MARGINAL
TEMP DIFFERENCES WILL NEGATE ANY LAKE RESPONSE AND THUS HAVE DRIED
THINGS OUT FROM NORTH TO SOUTH OVERNIGHT EARLY SUN.
NEXT MORE POTENT WAVE TO LIFT NORTH FROM THE OHIO VLY ON SUN WHICH
WILL ONCE AGAIN LIFT THE FRONT BACK NORTH THROUGH BEGINNING SUN
NGT. AS SUCH...EXPECT INCREASING CHANCES FOR RAIN ONCE AGAIN SUN
AFTERNOON AND EVENING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
MEDIUM RANGE MODELS CONTINUE TO SHOW FAIR AGREEMENT THROUGH THE
EXTENDED PERIOD.
SUNDAY NIGHT THROUGH MONDAY, SFC LOW PRES WILL TRACK FROM THE OHIO
VALLEY NORTHEAST ACROSS LAKE ERIE INTO NEARBY SOUTHERN ONTARIO.
WILL CARRY LIKELY POPS BOTH PERIODS WITH RAIN LIKELY SUNDAY NIGHT
FOLLOWED BY RAIN SHOWERS ON MONDAY AS TRAILING COLD FRONT CROSSES
AREA MONDAY AFTERNOON AND EVENING. THROUGH MONDAY EVENING TEMPS
WILL REMAIN WARM ENOUGH FOR JUST LIQUID PRECIP TO FALL. MONDAY
NIGHT AS TEMPS LOWER UNDER CAA AND NORTHWEST FLOW, A WEAK LAKE
RESPONSE MAY OCCUR INTO TUESDAY.
TUESDAY NIGHT THROUGH THURSDAY, LOOKS DRY WITH SFC HIGH PRES
STRETCHING FROM THE MID ATLANTIC REGION INTO NEW ENGLAND.
TEMPS THROUGH THE PERIOD WILL START WELL ABOVE NORMAL THEN FALL TO
SEASONAL LEVELS TUESDAY AND WEDNESDAY BEFORE MODERATING AGAIN ON
THURSDAY.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
VFR EXPECTED THROUGH LATE MORNING/EARLY AFTERNOON BEFORE RAIN AND
LOW CLOUDS BEGIN TO APPROACH FROM THE SOUTHWEST. LIGHT RAIN WILL
MOVE INTO PA TERMINALS BY 15Z THEN NORTH INTO KELM BY 16Z, KBGM BY
17Z, AND KITH BY 18Z. SIGNIFICANT DRY AIR WILL BE IN PLACE ACROSS
NORTHERN SITES WHERE RAIN WILL NOT MOVE IN UNTIL AFTER 00Z. BY THE
TIME THE RAIN STARTS, SURFACE TEMPERATURES WILL LIKELY RISE ABOVE
FREEZING TO PREVENT FREEZING RAIN AT AREA TERMINALS TODAY.
MVFR CIGS WILL SPREAD INTO HIGHER ELEVATION TERMINALS (KBGM AND
KITH) AFTER 18Z WITH REMAINING TERMINALS DELAYED UNTIL AFTER 20Z.
SOUTHEAST WIND WILL SLOWLY COME AROUND TO A MORE SOUTHERLY
DIRECTION THIS AFTERNOON AROUND 10KTS.
OUTLOOK...
SATURDAY...MVFR IN SHRA.
SATURDAY NIGHT/SUNDAY MORNING...PRIMARILY VFR.
SUNDAY AFTERNOON THROUGH MONDAY EVENING...RESTRICTIONS EXPECTED IN
RAIN.
TUESDAY...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG
SHORT TERM...CMG
LONG TERM...RRM
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1239 AM EST FRI DEC 7 2012
.SYNOPSIS...
WARMER AIR WILL MOVE INTO THE REGION FRIDAY AS A WEDGE OF HIGH
PRESSURE WEAKENS. ABOVE NORMAL TEMPERATURES WILL RETURN THIS WEEKEND
AS THE HIGH PUSHES OFFSHORE AND SOUTHERLY WINDS DEVELOP. A COLD
FRONT IS EXPECTED TO END THE WARMTH LATE TUESDAY...FOLLOWED BY HIGH
PRESSURE AND NEAR NORMAL TEMPERATURES NEXT WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 1230 AM FRIDAY...LARGE HOLES HAVE OPENED UP IN THE OVERCAST
CLOUD DECK ALONG THE COAST. A QUICK GLANCE OUT IN THE WEATHER OFFICE
PARKING LOT CONFIRMS TWINKLING STARS ABOVE WITH CLOUDS NEAR THE
HORIZON. SATELLITE IMAGERY SHOWS THIS IS PROBABLY A SHORT-LIVED
PHENOMENON...AS CONTINUED MOISTURE ADVECTION FROM THE SOUTH AND
SOUTHEAST SHOULD CLOSE THESE HOLES SOON WITH CLOUDY SKIES EXPECTED
MOST OF THE NIGHT. A BATCH OF RAIN AND EMBEDDED SHOWERS SOUTH OF
CAPE FEAR IS ASSOCIATED WITH WEAK ISENTROPIC LIFT PLUS SOME
CONVECTIVE INSTABILITY OUT TOWARD THE GULF STREAM. DESPITE THE
OVERLY-BULLISH HRRR FORECASTS OF RAIN DUMPING ACROSS THE GRAND
STRAND AND CAPE FEAR REGION THE REMAINDER OF THE NIGHT...I AM ONLY
FORECASTING 20-40 PERCENT COVERAGE OF RAIN TONIGHT...HIGHEST CHANCES
NEAR SOUTHPORT. TEMPERATURES ARE VIRTUALLY AT THEIR LOWS
CURRENTLY...AND STEADY TEMPERATURES IN THE 45-50 DEGREE RANGE ARE
ANTICIPATED THROUGH DAYBREAK. PREVIOUS DISCUSSION FOLLOWS...
OVERCAST CLOUD COVER FOR THE REMAINDER OF THE OVERNIGHT BASED ON
LATEST SAT IMAGERY TRENDS AND 1ST LOOK AT 00Z MODEL RH FIELDS. MILD
MOIST AIR TO OVERRIDE THE COOL SFC BASED LAYER TO LESS THAN 2K FT IN
DEPTH WEDGE DURING THE REMAINDER OF THE OVERNIGHT. LOW LEVEL CLOUD
DECK WILL DOMINATE IN THE 1K TO 3K FOOT LEVEL. WILL CONTINUE TO
CARRY PATCHY LIGHT RAIN OR DRIZZLE...WITH THE HIGHER CHANCE POPS
ALONG THE IMMEDIATE COAST. THIS A RESULT OF PCPN ACTIVITY DEVELOPING
ALONG THE INVERTED TROF JUST OFFSHORE...THAT COULD OCCASIONALLY
SPILL ONSHORE AS THE ENTIRE AREA OF PCPN GENERALLY LIFTS NORTHWARD.
850MB AND 925MB MODEL TEMP PROGS INDICATE WAA TO OCCUR
OVERNIGHT...HOWEVER THE DEPTH OF THE SFC BASED COOL AIR WILL
PREVENT THAT MILDER AIR FROM MIXING TO THE SFC. AS A
RESULT...TEMPS MAY DROP A DEGREE OR 3 FROM CURRENT VALUES...
BUT OVERALL TEMPS FOR THE REMAINDER OF THE NIGHT WILL LIKELY
REMAIN STEADY.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...BIT OF A TRICKY FORECAST FOR MOST OF THE
PERIOD MOST NOTABLY ON FRIDAY WITH SHALLOW COOL WEDGE IN PLACE.
SUCH FEATURES ARE NOTORIOUS FOR BEING DIFFICULT TO FORECAST WITH
REGARDS TO THEIR EROSION. ONE FACTOR ACTING TO SLIGHTLY BOLSTER THE
STRENGTH OF THE WEDGE IS FALLING PRESSURES UP AND DOWN THE EAST
COAST AS A WEAKENING UPPER LOW MOVES EAST OF FLORIDA. GUIDANCE IN
PRETTY GOOD AGREEMENT THOUGH IN BRINGING THIS FEATURE ASHORE LATE IN
THE DAY AND THE MILDER AIR ALONG WITH IT...POSSIBLY FOR A
NON-DIURNAL LATE DAY RISE IN TEMPS...TO A FEW DEGREES ABOVE CLIMO
EVEN. GIVEN THE WEDGE SCENARIO STAYED CLOSER TO/SLIGHTLY BELOW THE
COOLER NUMBERS. BUT ALSO SEEING HOW THIN THE MOISTURE IS WITH LARGE
BINOVCS OVER SOUTHERN ZONES A REPEAT PERFORMANCE TOMORROW VERY WELL
COULD LEAD TO A SLIGHTLY MILD LATE AFTERNOON. THE ABOVE SETUP ALWAYS
MAKES SOME LIGHT RAIN TO RULE OUT BUT SOME DRYNESS IN THE MID LEVEL
SHOULD KEEP IT TO THE VERY LIGHT/NON-MEASURABLE REALM FOR THE MOST
PART. CONFIDENCE IS HIGHER THAT THE WEDGE WILL BREAK DOWN FRIDAY
NIGHT INTO SATURDAY BRINGING A BETTER CHANCE OF SOME UNSEASONABLE
WARMTH. THE COPIOUS MOISTURE THAT HAD BEEN AROUND DURING MUCH OF
FRIDAY IN ASSOCIATION WITH THE WEDGE WILL HAVE LITTLE TO SCOUR IT
OUT SO THE SKY MAY STAY FAIRLY CLOUDY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 3 PM THURSDAY...UNSEASONABLY WARM WEATHER SUN AND MON...A
RESULT OF WEAK SURFACE AND MID LEVEL RIDGING...WILL BE REPLACED BY
CONDITIONS MORE TYPICAL OF EARLY DECEMBER IN THE CAROLINAS FOR THE
REMAINDER OF THE PERIOD. COLD FRONT CROSSES THE REGION TUE MORNING
AHEAD OF MID LEVEL LONG WAVE TROUGH MOVING EAST ACROSS EASTERN
CONUS. FRONT WILL PROBABLY BE ACCOMPANIED BY A BROKEN LINE OF
CONVECTION...HOW VIGOROUS THIS LINE IS REMAINS TO BE SEEN. FRONT
PASSES EARLIER IN THE DAY WITH THE BEST DYNAMICS AND MOISTURE TO THE
NORTH. BEST PRECIP CHANCES MAY END UP BEING ASSOCIATED WITH DIURNAL
CONVECTION IN THE WARM SECTOR MON AFTERNOON. HOWEVER GIVEN THE TIME
RANGE AND UNCERTAINTY WILL HOLD SLIGHT CHANCE/LOW CHANCE MON THROUGH
TUE FOR NOW.
MEDIUM RANGE GUIDANCE DIFFERING A BIT ON WHETHER POSITIVELY TILTED
MID LEVEL TROUGH HOLDS THE FRONT NEAR THE COAST TUE NIGHT AND WED
BEFORE PASSAGE OF SHORTWAVE WED NIGHT HELPS KICK THE TROUGH AXIS
FARTHER OFFSHORE. EITHER WAY THE AREA SHOULD REMAIN DRY...BUT FRONT
STALLED CLOSER TO THE COAST WOULD RESULT IN MORE CLOUD COVER AND
COOLER HIGHS. PERIOD ENDS WITH PROGRESSIVE PATTERN ALOFT AND SURFACE
HIGH BUILDING IN FROM THE NORTH.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...PREDOMINANTLY MVFR CIGS ACROSS THE AREA WITH NORTHEAST
SFC WINDS 5-10 KNOTS. CIGS ARE EXPECTED TO LOWER TO IFR ALONG THE
COAST AROUND 10Z...HOPEFULLY REMAINING JUST AT/JUST ABOVE 1000 FT
INLAND. THE NAM/RUC FORECASTS HAVE BEEN CONSISTENT WITH IFR CIGS AT
KMYR/KCRE AND KILM. CIGS SHOULD GRADUALLY LIFT TO MVFR/VFR LEVELS BY
LATE MORNING/EARLY AFTERNOON. AN INVERTED COASTAL TROUGH IS EXPECTED
TO PRODUCE SHOWER ACTIVITY MAINLY OFFSHORE...BUT HAVE INCLUDED VCSH
AT CRE/MYR AND SOME LIGHT SHOWERS AT ILM BEFORE DAYBREAK. AFTER 00Z
TONIGHT...FOG/STRATUS WILL LIKELY IMPACT THE AREA THROUGH AND AFTER
06Z.
EXTENDED OUTLOOK...MORNING FOG/STRATUS POSSIBLE SATURDAY THROUGH
MONDAY. SHOWERS POSSIBLE TUESDAY ASSOCIATED WITH A COLD FRONT.
OTHERWISE VFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 1230 AM FRIDAY...VIRTUALLY NO CHANGES HAVE BEEN MADE TO THE
FORECAST AT THIS EARLY HOUR. THE PREVIOUS FORECAST REMAINS IN GOOD
SHAPE. PREVIOUS DISCUSSION FOLLOWS...
A TIGHTENED SFC PG WILL RESIDE ACROSS THE LOCAL WATERS FOR THE
REMAINDER OF THE OVERNIGHT. THIS DUE TO A SFC RIDGE AXIS...AKA THE
WEDGE...EXTENDING NE-SW ACROSS THE CENTRAL CAROLINAS...AND THE
INVERTED SFC TROF AXIS JUST OFFSHORE AND PARALLEL TO THE CAROLINA
COASTLINES. WINDS WILL RUN NE 15 TO 25 KT AND SIGNIFICANT SEAS OF
3 TO 6 FT. EXCEPT...UP TO 7 FT ACROSS THE OUTER WATERS OFF CAPE
FEAR. 41013 HAS REPORTED 8 FT SEAS THIS AFTERNOON AND ALL THIS
EVENING. NEAR SHORE...SEAS WILL RUN 2 TO 3 FT SOUTH OF CAPE FEAR
TO LITTLE RIVER INLET. SIGNIFICANT SEAS WILL PRIMARILY BE A
FUNCTION OF THE LOCALLY PRODUCED WIND WAVES EXHIBITING 7 SECOND
DOMINATING PERIODS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...A WEDGE OF SURFACE HIGH PRESSURE WILL STAY
ENTRENCHED ACROSS THE LANDMASS FOR MOST OF FRIDAY. MEANWHILE A
SURFACE FRONT/TROUGH WILL STRENGTHEN OFFSHORE AND BEGIN TO MOVE
TOWARDS THE COAST. THE SPEED AT WHICH THIS HAPPENS IS A LITTLE
UNCERTAIN SINCE SHALLOW WEDGES OF COOL AIR ARE NOTORIOUSLY POORLY
MODELED AND TEND TO EXIST LONGER THAN FORECASTED. MAIN EFFECT ON THE
LOCAL FORECAST AREA WILL BE THE TIMING OF THE WINDS GOING FROM NE TO
EAST AS THE BOUNDARY DRAWS NEARER TO THE COAST. ADDITIONAL VEERING
TO SOUTHERLY IS THEN SLATED FOR FRIDAY NIGHT ALONG WITH A SMALL
INCREASE IN THE WIND SPEED AS THE WEDGE LIFTS OUT AND THE LARGE HIGH
OVER THE WESTERN ATLANTIC MAKES A SMALL PRESENCE ALONG THE COAST. AS
A RESULT THERE COULD BE A SHORT WINDOW OF SCEC-WORTHY SEAS ALONG
NORTHERN ZONES. WEST ATLANTIC HIGH PRESSURE WILL BRING EITHER SW OR
W WINDS ON SATURDAY DEPENDING ON HOW FAR SOUTH A BACKDOOR COLD FRONT
SINKS SOUTH OF THE MASON-DIXON LINE.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 3 PM THURSDAY...SOUTHERLY FLOW ACROSS THE WATERS SUN AND SUN
NIGHT BECOMES SOUTHWEST AND INCREASES MON AS GRADIENT TIGHTENS AHEAD
OF APPROACHING COLD FRONT. ANTICIPATE A SOLID 20 KT LATER MON WITH
SEAS LIKELY EXCEEDING 6 FT ACROSS WATERS OPEN TO SOUTHWEST FETCH.
WOULD EXPECT SCA HEADLINE FOR ALL ZONES BEGINNING MON AFTERNOON THEN
ENDING TUE MORNING AS FRONT PUSHES OFF THE COAST AND FLOW BECOMES
OFFSHORE. LIMITED COLD ADVECTION IN THE WAKE OF THE FRONT WILL KEEP
WINDS AND SEAS BELOW HEADLINE CRITERIA.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR AMZ256.
SMALL CRAFT ADVISORY UNTIL 3 AM EST FRIDAY FOR AMZ250-252-254.
&&
$$
SYNOPSIS...TRA
NEAR TERM...DCH/TRA
SHORT TERM...MBB
LONG TERM...III
AVIATION...BJR/TRA
AREA FORECAST DISCUSSION
NWS GOODLAND KS
758 AM MST FRI DEC 7 2012
.UPDATE...
ISSUED AT 748 AM MST FRI DEC 7 2012
RADAR IMAGERY OVER THE LAST HOUR HAS SHOWN SOME WEAK ECHOES OVER
THE MCCOOK AND NORTON AREAS. SURFACE TEMPERATURES HAVE BEEN AROUND
30 DEGREES AND THE RUC SOUNDING FROM MCCOOK INDICATED NO ICE BEING
INTRODUCED INTO THE MID/LOW LEVEL CLOUDS. CALLED THE MCCOOK
DISPATCH WHO REPORTED DRIZZLE...WITH NO ICE ACCUMULATING EVEN ON
ELEVATED SURFACES. WITH THIS IN MIND...AND TEMPERATURES CONTINUING
TO WARM...DECIDED TO CALL THIS DRIZZLE FOR THE FORECAST.
ISENTROPIC ANALYSIS INDICATES THE LIFT FOR THIS AREA WILL LAST
THROUGH THE MORNING THEN MOVE EAST OUT OF THE AREA DURING THE
EARLY AFTERNOON AHEAD OF THE WEAK COLD FRONT. ALSO MENTION
SLIGHTLY REDUCED VISIBILITIES IN THE DRIZZLE DUE TO MCCOOK
REPORTING 4 MILES BRIEFLY THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 231 AM MST FRI DEC 7 2012
AS OF 2 AM...SKIES ACROSS THE TRI-STATE AREA WERE PARTLY CLOUDY TO
MOSTLY CLOUDY. TEMPERATURES WERE IN THE MID 20S TO MID 30S ACROSS
THE REGION. WINDS WERE GENERALLY LIGHT BUT SOUTH WINDS HAVE STARTED
TO PICK UP A LITTLE OVER EASTERN COLORADO AHEAD OF A DEVELOPING
LEE TROUGH.
THE LEE TROUGH WILL MOVE ACROSS THE REGION THIS AFTERNOON...ALLOWING
SOUTH WINDS TO BECOME NORTHWEST WINDS AFTER THE TROUGH PASSAGE. SKY
FORECAST FOR TODAY IS SOMEWHAT TRICKY AND LARGELY DEPENDS ON THE
AMOUNT OF CIRRUS THAT DEVELOPS TO THE WEST. WENT WITH PARTLY CLOUDY
SKIES FOR MOST OF THE DAY. HIGH TEMPERATURES WILL BE IN THE LOW TO
MID 50S FOR TODAY. THIS WILL BE THE WARMEST DAY FOR AT LEAST THE
NEXT WEEK AS A FEW COLD FRONTS WILL MOVE THROUGH AND KEEP THINGS
QUITE COLD.
A LARGE LONGWAVE TROUGH WILL BEGIN PUSHING INTO THE AREA ON
SATURDAY. MODELS ARE BEGINNING TO AGREE ON A SOLUTION THAT IS NOT
TOO FAVORABLE FOR PRECIPITATION IN THE REGION. MODELS ARE
PROJECTING A SPLIT FLOW PATTERN WITH THE TRI-STATE AREA IN THE
MIDDLE. ALL MODELS ALSO SHOW THAT TWO SEPARATE LOW PRESSURE
SYSTEMS WILL DEVELOP AHEAD OF THIS UPPER LEVEL DISTURBANCE. THE
FIRST WILL DEVELOP OVER THE NORTHERN PLAINS. THIS LOW PRESSURE
WILL MOVE TOWARDS MINNESOTA AND KEEP MOST OF THE BEST FORCING AND
PRECIPITATION OVER NEBRASKA AND SOUTH DAKOTA. THE SECOND LOW
PRESSURE WILL DEVELOP TO THE SOUTH...OVER THE TEXAS PANHANDLE.
THIS SECOND SOLUTION WOULD FAVOR A BETTER CHANCE FOR PRECIPITATION
ACROSS KANSAS. MODELS DISAGREE ON HOW STRONG THE LOW PRESSURES
WILL BE. THE EUROPEAN IS THE ONLY MODEL THAT SHOWS THE SOUTHERN
LOW BECOMING THE DOMINANT LOW...WHICH WOULD BE MORE FAVORABLE FOR
PRECIPITATION HERE IN THE TRI-STATE AREA. UNFORTUNATELY...THE
PRECIPITATION FOR THE EUROPEAN MODEL LOOKS A LITTLE OVERDONE
CONSIDERING THE AMOUNT OF DRY AIR THAT WILL MOVE IN WITH THIS
FRONT. AS A RESULT...HAVE LEANED TOWARDS THE DRIER SOLUTIONS OF
THE NAM...CANADIAN AND GFS MODELS. THE MODELS DO HAVE SOME
VARIABLES THAT WOULD FAVOR HIGHER SNOWFALL AMOUNTS...HOWEVER THE
AMOUNT OF DRY AIR LOOKS LIKE TOO MUCH TO OVERCOME AT THE PRESENT
MOMENT. MODEL CONSISTENCY IS INCREASING WITH THE EUROPEAN
REMAINING AS THE ONLY OUTLIER.
THE COLD FRONT WILL PASS THROUGH LATE SATURDAY EVENING AND INTO
SATURDAY NIGHT. SOME SNOW SHOWERS ARE POSSIBLE ALONG THE
FRONT...HOWEVER DUE TO THE DRY AIR ACCUMULATIONS WILL LIKELY BE ONE
INCH OR LESS. TEMPERATURES WILL BE QUITE COLD BEHIND THE FRONT WITH
STRONG NORTH WINDS. HIGH TEMPERATURES ON SUNDAY WILL LIKELY NOT MAKE
IT INTO THE 30S. LOW TEMPERATURES ON SUNDAY NIGHT WILL FALL INTO THE
SINGLE DIGITS ACROSS MOST OF THE REGION...WITH WIND CHILL READINGS
AS LOW AS ZERO OR POSSIBLY BELOW ZERO. LOW TEMPERATURES COULD
FALL LOWER THAN FORECAST IF SKIES CLEAR QUICKER THAN EXPECTED AS A
DRY SLOT MOVES INTO THE BACK OF THE DEPARTING WEATHER SYSTEM.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 231 AM MST FRI DEC 7 2012
TROUGH WILL REMAIN IN PLACE ACROSS THE HIGH/CENTRAL PLAINS THROUGH
TUESDAY WITH SHORTWAVE RIDGE BUILDING BACK INTO THE INTER-MOUNTAIN
WEST BY WEDNESDAY. RESULT WILL BE A GRADUAL WARM-UP WITH BELOW
NORMAL HIGH TEMPS IN THE 30S MONDAY AND UPPER 30S/LOW 40S TUESDAY.
THERE IS QUITE A BIT OF SPREAD BETWEEN ECMWF AND GFS REGARDING
SHORTWAVE RIDGE WED. FOR NOW ABOVE NORMAL TEMPS IN THE UPPER 40S ARE
FORECAST...HOWEVER SPREAD IN GUIDANCE COULD SUPPORT TEMPS 5F COOLER
OR WARMER THAN THIS. HIGH TEMPS SHOULD BE NEAR SEASONAL LEVELS
THU...THOUGH THERE IS INDICATION FROM PREVIOUS MODEL RUNS OF
POSSIBLE FROPA THAT COULD RESULT IN SLIGHTLY COOLER TEMPS THAN
CURRENTLY IN THERE. NOT ENOUGH CONFIDENCE TO GO LOWER THAN UPPER
30S/LOW 40S FOR HIGHS THU. SUBSIDENCE AND DRY AIR MASS SHOULD BE IN
PLACE THROUGH THURSDAY...SO I LEFT FORECAST DRY.
BY THE END OF NEXT WEEK ANOTHER TROUGH WILL BUILD OVER THE WESTERN
US TOWARDS THE INTER-MOUNTAIN WEST THAT COULD BRING ANOTHER ARCTIC
AIR MASS AND POSSIBLE SNOW CHANCES BY NEXT WEEKEND. THIS IS
PRIMARILY OUTSIDE THE VALID FORECAST PERIOD...SO WILL NOT AFFECT THE
ONGOING FORECAST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 423 AM MST FRI DEC 7 2012
VFR CONDITIONS ARE EXPECTED TO CONTINUE FOR THE NEXT 24 HOURS.
MID-LEVEL CLOUDS HAVE DEVELOPED OVER THE TAF SITES THIS MORNING
BUT SHOULD DISSIPATE LATER THIS MORNING. HIGH-LEVEL CIRRUS WILL
CONTINUE TO STREAM OVER WITH MID-LEVEL CLOUDS EXPECTED TO DEVELOP
AGAIN TONIGHT. SOUTH WINDS WILL BECOME NORTH WINDS ON THE BACK
SIDE OF A LEE TROUGH THAT WILL MOVE THROUGH THIS AFTERNOON. WINDS
WILL AGAIN BECOME SOUTH DURING THE OVERNIGHT HOURS TONIGHT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...RRH
LONG TERM...DR
AVIATION...RRH
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
936 AM CST FRI DEC 7 2012
.UPDATE...
FOG IS BEGINNING TO LIFT THIS MORNING AND WILL END THE DENSE FOG
ADVISORY. OTHERWISE SKIES WILL BE CLEARING ALLOWING TEMPERATURES
TO WARM INTO THE MID 70S TODAY. WE ARE IN THIS SAME PATTERN FOR
TOMORROW WITH CHANGES IN THE WEATHER TO BEGIN ON SUNDAY AS
ANOTHER COLD FRONT DROPS DOWN FROM THE PLAINS STATES.
&&
.PREV DISCUSSION... /ISSUED 608 AM CST FRI DEC 7 2012/
AVIATION...BLO MINS CONDITIONS EXCEPT BPT WHERE STRATCU CIGS
STAYED IN MOST OF THE NIGHT AND WINDS WERE A BIT STRONGER AND SWLY
AT GRADIENT LEVELS. OTHERWISE IMPROVEMENT ABV MINS SHORTLY AT AEX,
AND IN A COUPLE OF HOURS AT LCH AS SWLY BOUNDARY LEVEL FLOW
BEGINS TO LIFT THE FOG TOWARDS MVFR.
BY MID MORNING ACADIANA AIRPORTS ARA AND LFT SHOULD FOLLOW SUIT
AS TEMPS APPROACH BURNOFF OF 65F/18C. STILL LOOKING VFR FOR AEX AS
WELL AS LFT AND ARA THIS AFTERNOON. MVFR CIGS SHOULD HANG IN THE REST OF
THE DAY AT BPT AND LCH LOOKING AT LATEST RUC TRENDS. VLIFR
CONDITIONS SHOULD REPEAT STARTING LATE EVENING AS THE WEAK DECEMBER
SUN AND AN INVERSION HAS TRAPPED LOW LEVEL MOISTURE IN PLACE.
SWEENEY
PREV DISCUSSION... /ISSUED 412 AM CST FRI DEC 7 2012/
SYNOPSIS...
AN ATLANTIC DOME OF HIGH PRESSURE...LOCATED OFFSHORE THE
CAROLINA`S...RIDGES WESTWARD THROUGH SOUTHEAST LOUISIANA.
DISCUSSION...
DRY MEXICAN AIR IS RIDING IN ON A LOW LEVEL SOUTHWESTERLY AIRSTREAM.
THE OVERRIDING DRY AIR IS TRAPPING MOISTURE NEAR THE SURFACE.
PATCHY DENSE FOG IS BEING REPORTED THROUGH MOST OF SOUTHWEST LOUISIANA.
A DENSE FOG ADVISORY WILL REMAIN IN EFFECT.
OTHERWISE...A WARM CONVEYOR BELT AIRSTREAM IS BECOMING BETTER
ESTABLISHED WITHIN THE SURFACE LAYER. CAMPECHE AIR IS RIDING IN ON
INCREASING SOUTHERLY WINDS.
THE AFTERNOON READINGS WILL BE RUNNING FROM 10 TO 15 DEGREES ABOVE
NORMAL. THE AFTERNOON HUMIDITIES WILL BE RUNNING WELL ABOVE NORMAL.
FOR TONIGHT...PATCHY FOG IS EXPECTED TO RETURN. OTHERWISE...THE
OVERNIGHT MINIMUMS WILL BE RUNNING FROM 15 TO 20 DEGREES ABOVE NORMAL.
OUTLOOK...
A STRONG CANADIAN FRONT WILL TRAVEL THROUGH THE FORECAST AREA
DURING THE OVERNIGHT HOURS ON SUNDAY.
NUMEROUS SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THIS SYSTEM.
21
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 75 60 78 61 77 / 10 10 10 10 20
KBPT 75 61 78 63 77 / 10 10 20 10 20
KAEX 74 57 77 59 77 / 10 10 10 10 20
KLFT 75 59 78 59 77 / 10 10 10 10 20
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
608 AM CST FRI DEC 7 2012
.AVIATION...BLO MINS CONDITIONS EXCEPT BPT WHERE STRATCU CIGS
STAYED IN MOST OF THE NIGHT AND WINDS WERE A BIT STRONGER AND SWLY
AT GRADIENT LEVELS. OTHERWISE IMPROVEMENT ABV MINS SHORTLY AT AEX,
AND IN A COUPLE OF HOURS AT LCH AS SWLY BOUNDARY LEVEL FLOW
BEGINS TO LIFT THE FOG TOWARDS MVFR.
BY MID MORNING ACADIANA AIRPORTS ARA AND LFT SHOULD FOLLOW SUIT
AS TEMPS APPROACH BURNOFF OF 65F/18C. STILL LOOKING VFR FOR AEX AS
WELL AS LFT AND ARA THIS AFTERNOON. MVFR CIGS SHOULD HANG IN THE REST OF
THE DAY AT BPT AND LCH LOOKING AT LATEST RUC TRENDS. VLIFR
CONDTIONS SHOULD REPEAT STARTING LATE EVENING AS THE WEAK DECEMBER
SUN AND AN INVERSION HAS TRAPPED LOW LEVEL MOISTURE IN PLACE.
SWEENEY
&&
.PREV DISCUSSION... /ISSUED 412 AM CST FRI DEC 7 2012/
SYNOPSIS...
AN ATLANTIC DOME OF HIGH PRESSURE...LOCATED OFFSHORE THE
CAROLINAS...RIDGES WESTWARD THROUGH SOUTHEAST LOUISIANA.
DISCUSSION...
DRY MEXICAN AIR IS RIDING IN ON A LOW LEVEL SOUTHWESTERLY AIRSTREAM.
THE OVERRIDING DRY AIR IS TRAPPING MOISTURE NEAR THE SURFACE.
PATCHY DENSE FOG IS BEING REPORTED THROUGH MOST OF SOUTHWEST LOUISIANA.
A DENSE FOG ADVISORY WILL REMAIN IN EFFECT.
OTHERWISE...A WARM CONVEYOR BELT AIRSTREAM IS BECOMING BETTER
ESTABLISHED WITHIN THE SURFACE LAYER. CAMPECHE AIR IS RIDING IN ON
INCREASING SOUTHERLY WINDS.
THE AFTERNOON READINGS WILL BE RUNNING FROM 10 TO 15 DEGREES ABOVE
NORMAL. THE AFTERNOON HUMIDITIES WILL BE RUNNING WELL ABOVE NORMAL.
FOR TONIGHT...PATCHY FOG IS EXPECTED TO RETURN. OTHERWISE...THE
OVERNIGHT MINIMUMS WILL BE RUNNING FROM 15 TO 20 DEGREES ABOVE NORMAL.
OUTLOOK...
A STRONG CANADIAN FRONT WILL TRAVEL THROUGH THE FORECAST AREA
DURING THE OVERNIGHT HOURS ON SUNDAY.
NUMEROUS SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THIS SYSTEM.
21
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 75 60 78 61 77 / 10 10 10 10 20
KBPT 75 61 78 63 77 / 10 10 20 10 20
KAEX 74 57 77 59 77 / 10 10 10 10 20
KLFT 75 59 78 59 77 / 10 10 10 10 20
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING
ZONES: ACADIA...ALLEN...AVOYELLES...BEAUREGARD...
CALCASIEU...EAST CAMERON...EVANGELINE...IBERIA...JEFFERSON
DAVIS...LAFAYETTE...LOWER ST. MARTIN...RAPIDES...ST.
LANDRY...ST. MARY...UPPER ST. MARTIN...VERMILION...VERNON...
WEST CAMERON.
TX...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
902 AM EST FRI DEC 7 2012
.SYNOPSIS...
A STATIONARY FRONT WILL BE THE FOCUS FOR PERIODS OF RAIN ACROSS
THE UPPER OHIO VALLEY INTO EARLY NEXT WEEK...AS A SERIES OF LOW
PRESSURE SYSTEMS MOVE EASTWARD ALONG THE STALLED FRONT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MORNING UPDATE TO REMOVE ANY MENTION OF FREEZING RAIN OR DRIZZLE
ACROSS THE FAR NORTH. BUMPED UP MAX TEMPERATURES A DEGREE OR SO
ACROSS THE FAR SOUTH MAINLY KMGW TO ACCOUNT FOR CURRENT READINGS.
PER RECENT RADAR DATA AND RAP MODEL OUTPUT...EXPECT FREQUENT
PERIODS OF RAIN ACROSS THE UPPER OHIO VALLEY...AS THE INITIAL LOW
PRESSURE CENTER MOVES NORTHEASTWARD ALONG THE STATIONARY FRONT
THAT STRADDLES THE I-70 CORRIDOR.
HIGHER ELEVATIONS CAN BE SHROUDED IN LOW CLOUDS...SO HAVE ADDED
PATCHY FOG THIS MORNING FOR AREAS HIGHER THAN 2500 FT MSL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
MILD AND WET WEA WL DOMINATE THE SHORT TERM PD AS A SERIES OF
DISTURBANCES TRIGGER WARM...MOIST ADVCTN AND PCPN AS THEY MOVE
ALONG A NEAR-STATIONARY FRONT PROJECTED OVR THE UPR OH VALLEY REGION.
BREAKS IN THE PCPN CAN BE EXPECTED WITH PASSAGE OF THE INDIVIDUAL
SHORTWAVES.
WARM TEMPS WERE FORECAST USING A MIX OF SREF/MAV NUMBERS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
CLOUDS AND WET WEATHER CONTINUE INTO EARLY NEXT WEEK. SHORTWAVE
THAT IS PROJECTED ACRS THE GREAT LAKES ON MONDAY INTO TUESDAY IS
FORECAST TO PUSH THE FRONT SUFFICIENTLY EWD TO END THE WET SPELL.
COLD ADVCTN IN THE WAKE OF THE FRONT WITH UPSLOPE/LAKE ENHANCEMENT
MAY SPPRT SOME SNOW SHOWERS FOR TUE AND TUE NGT...BUT DO NOT
FORESEE MUCH ACCUM AT THIS JUNCTURE AS THE MAGNITUDE AND DEPTH OF
THE COLD POOL RMNS QNABLE.
SEASONAL TEMPERATURES AND DRY WX ARE EXPECTED TO QUICKLY RTN THOUGH
AS SW FLOW RESUMES WED AND CONTS THROUGH THE BALANCE OF THE
PERIOD.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
RECENT RADAR AND SURFACE DATA...COUPLED WITH RECENT RAP AND WRF-
NMM MODEL OUTPUT...SHOWS SURGES OF RAIN...ASSOCIATED WITH LOW
PRESSURE CENTERS MOVING NORTHEASTWARD ALONG THE I-70 STATIONARY
FRONT...WILL CONTINUE TO MOVE NORTHEASTWARD ACROSS THE UPPER OHIO
VALLEY TODAY INTO FRIDAY. AS RAIN-MOISTENED SURFACE LAYER
SATURATES..CONDITIONS WILL LOWER TO MAINLY IFR BY 14Z...AND
PERHAPS LIFR TONIGHT.
SURFACE WINDS WILL BE MAINLY FROM THE SOUTH AT NO MORE THAN 10
KTS.
.OUTLOOK.../SATURDAY NIGHT THROUGH TUESDAY/...
FREQUENT IFR RESTRICTIONS DUE TO RAIN FOG AND STRATUS WILL CONTINUE
INTO TUESDAY DUE TO A SERIES OF LOW PRESSURE SYSTEMS MOVING EASTWARD
ALONG THE STALLED FRONT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
610 AM EST FRI DEC 7 2012
.SYNOPSIS...
A STATIONARY FRONT WILL BE THE FOCUS FOR PERIODS OF RAIN ACROSS
THE UPPER OHIO VALLEY INTO EARLY NEXT WEEK...AS A SERIES OF LOW
PRESSURE SYSTEMS MOVE EASTWARD ALONG THE STALLED FRONT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PER RECENT RADAR DATA AND RAP MODEL OUTPUT...EXPECT FREQUENT PERIODS
OF RAIN ACROSS THE UPPER OHIO VALLEY...AS THE INITIAL LOW PRESSURE
CENTER MOVES NORTHEASTWARD ALONG THE STATIONARY FRONT THAT
STRADDLES THE I-70 CORRIDOR.
SURFACE DATA SUGGESTS AIR TEMPERATURES NEAR FREEZING CLOSE TO THE
APPALACHIAN MOUNTAINS. HOWEVER ROAD SENSORS SUGGEST PAVEMENTS CAN
BE WARMER. SO EXPECT ANY PATCHES OF FREEZING RAIN WILL HAVE ENDED
BY DAYBREAK AT 7 AM...WITH TEMPERATURES CLIMBING TO VALUES UP TO
10 DEGREES WARMER THAN NORMAL THIS AFTERNOON PER RECENT GFS AND
NAM MOS.
HIGHER ELEVATIONS CAN BE SHROUDED IN LOW CLOUDS...SO HAVE ADDED
PATCHY FOG THIS MORNING FOR AREAS HIGHER THAN 2500 FT MSL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
MILD AND WET WEA WL DOMINATE THE SHORT TERM PD AS A SERIES OF
DISTURBANCES TRIGGER WARM...MOIST ADVCTN AND PCPN AS THEY MOVE
ALONG A NEAR-STATIONARY FRONT PROJECTED OVR THE UPR OH VALLEY REGION.
BREAKS IN THE PCPN CAN BE EXPECTED WITH PASSAGE OF THE INDIVIDUAL
SHORTWAVES.
WARM TEMPS WERE FORECAST USING A MIX OF SREF/MAV NUMBERS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
CLOUDS AND WET WEATHER CONTINUE INTO EARLY NEXT WEEK. SHORTWAVE
THAT IS PROJECTED ACRS THE GREAT LAKES ON MONDAY INTO TUESDAY IS
FORECAST TO PUSH THE FRONT SUFFICIENTLY EWD TO END THE WET SPELL.
COLD ADVCTN IN THE WAKE OF THE FRONT WITH UPSLOPE/LAKE ENHANCEMENT
MAY SPPRT SOME SNOW SHOWERS FOR TUE AND TUE NGT...BUT DO NOT
FORESEE MUCH ACCUM AT THIS JUNCTURE AS THE MAGNITUDE AND DEPTH OF
THE COLD POOL RMNS QNABLE.
SEASONAL TEMPERATURES AND DRY WX ARE EXPECTED TO QUICKLY RTN THOUGH
AS SW FLOW RESUMES WED AND CONTS THROUGH THE BALANCE OF THE
PERIOD.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
RECENT RADAR AND SURFACE DATA...COUPLED WITH RECENT RAP AND WRF-
NMM MODEL OUTPUT...SHOWS SURGES OF RAIN...ASSOCIATED WITH LOW
PRESSURE CENTERS MOVING NORTHEASTWARD ALONG THE I-70 STATIONARY
FRONT...WILL CONTINUE TO MOVE NORTHEASTWARD ACROSS THE UPPER OHIO
VALLEY TODAY INTO FRIDAY. AS RAIN-MOISTENED SURFACE LAYER
SATURATES..CONDITIONS WILL LOWER TO MAINLY IFR BY 14Z...AND
PERHAPS LIFR TONIGHT.
SURFACE WINDS WILL BE MAINLY FROM THE SOUTH AT NO MORE THAN 10
KTS.
.OUTLOOK.../SATURDAY NIGHT THROUGH TUESDAY/...
FREQUENT IFR RESTRICTIONS DUE TO RAIN FOG AND STRATUS WILL CONTINUE
INTO TUESDAY DUE TO A SERIES OF LOW PRESSURE SYSTEMS MOVING EASTWARD
ALONG THE STALLED FRONT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
545 AM CST FRI DEC 7 2012
.UPDATED FOR THE 12Z AVIATION DISCUSSION BELOW...
.DISCUSSION...
PLENTY OF CONCERNS THIS MORNING WITH TWO WEATHER SYSTEMS MOVING
THROUGH FROM TODAY THROUGH SUNDAY.
THE FIRST IS A MID LEVEL LOW APPROACHING CENTRAL SD EARLY THIS
MORNING. THIS FEATURE IS PROGGED TO MOVE EAST AND PASS ACROSS
SOUTHERN MN THIS EVENING. ACCOMPANYING THE LOW IS A FAIRLY STRONG
BAND OF FRONTOGENESIS AND OMEGA AT -15 DEG C. THE PROBLEM IS THE
FORCING AND MODEL QPF...ESPECIALLY FROM THE GFS...ARE NOT IN SYNC.
IN ADDITION...THERE IS GOOD CONSENSUS ON A PV MAX MOVING ACROSS
SOUTHERN MN ALONG WITH A 120M HEIGHT FALL CENTER. RAP GUIDANCE
POINTS TO SW AND SOUTH CENTRAL MN FOR THE MOST QPF WHICH AGREES
MUCH BETTER WITH THE FORCING. PRECIP AMOUNTS ARE IN THE .10 TO .25
INCH RANGE WITH THE MOST IN OUR FAR SW MN COUNTIES. THE NAM AND
GFS ARE SIMILAR BUT MUCH FARTHER NORTH. FOLLOWING THE FORCING
SEEMS TO BE THE MOST CORRECT THING TO DO AND THIS WOULD PLACE NEAR
ADVISORY SNOWFALL OVER SW AND PARTS OF SOUTH CENTRAL MN DURING THE
AFTERNOON AND EVENING. THE TREND ON THIS WEATHER SYSTEM OVER THE
PAST TWO NIGHTS HAS BEEN GETTING STRONGER AND TAKING LONGER TO
WEAKEN DURING THE OVERNIGHT HOURS. THERE IS ALSO QUITE THE SNOW
BAND IN WESTERN/CENTRAL SD NORTH OF I-90. THEREFORE..USED
FORECASTER DISCRETION AND ISSUED A WINTER WEATHER ADVISORY FROM
WEST CENTRAL INTO SOUTH CENTRAL MN FOR THIS AFTERNOON AND EVENING.
WE CURRENTLY HAVE 2 TO 2.5 INCHES IN THE ADVISORY AREA...BUT
CONCERNED AMOUNTS MAY BE HIGHER IN THE BAND OF MID LEVEL -FN
VECTOR DIVERGENCE. STILL HAVE SNOW SPREADING ACROSS THE TWIN
CITIES DURING THE AFTERNOON AND EVENING WITH AMOUNTS UP TO ONE
INCH.
THE SECOND CONCERN IS A MUCH STRONGER LOW PRESSURE SYSTEM FORECAST
ACROSS THE REGION SATURDAY NIGHT AND SUNDAY. NAM/GFS/ECMWF STILL
SHOW A MID LEVEL LOW PASSING ACROSS CENTRAL MN AND NORTHERN WI
DURING THIS PERIOD. A BAND OF WAA SNOW WILL PRECEDE THE LOW WITH
DEFORMATION SNOW CONTINUING FROM WEST CENTRAL MN INTO THE
ARROWHEAD ON SUNDAY. THE TOP THREE CIPS ANALOGS ALL HAD 6+ INCHES
OF SNOW ACROSS CENTRAL MN WITH A FOOT OR MORE FOR THE NORTH. THE
TREND ON THIS WEATHER SYSTEM OVER THE PAST FEW NIGHT IS FARTHER
SOUTH WITH THE SFC/MID LEVEL LOW PRESSURE. THIS SYSTEM IS
ACCOMPANIED BY A VERY STRONG PV BOOT SATURDAY NIGHT AND SUNDAY
POINTING INTO WEST CENTRAL AND NORTHERN AREAS OF MN. THE SURFACE
GRADIENT THAT DEVELOPS OVER WESTERN MN SUNDAY MORNING IS ALARMING.
BUFKIT NAM/GFS PROFILE DATA FOR KMOX SHOW WINDS JUST OFF THE
SURFACE IN THE 25-29 KNOT RANGE WITH TOP OF THE CHANNEL IN THE
38-43 KNOT RANGE. DEPENDING ON HOW MUCH SNOW FALLS...AND IF THE
WINDS VERIFY...THIS COULD END UP BEING A BLIZZARD FOR PARTS OF THE
WEST ON SUNDAY. TEMPERATURES WILL ALSO BE STEADY OR FALLING IN
THE TEENS WITH BELOW ZERO TEMPERATURES EXPECTED SUNDAY NIGHT.
AFTER QUITE A BIT OF COLLABORATION WITH KDLH...KARX AND KABR...WE
FELT IT WAS PRUDENT TO ISSUE A WINTER STORM WATCH FOR SATURDAY
NIGHT AND SUNDAY. CURRENT SNOW ACCUMULATION GRIDS ARE IN THE 5 TO
7 INCH RANGE ACROSS CENTRAL MN AND PARTS OF WEST CENTRAL WI.
CURRENTLY HAVE 4 TO 5 INCHES FOR THE TWIN CITIES.
LITTLE TIME SPENT ON LONGER TERM GRIDS WITH THE CRH EXTEND
ACCEPTED. A QUICK GLANCE FOR THE MONDAY THROUGH THURSDAY PERIOD
SHOWS ONLY WEAK WEATHER SYSTEM PASSING BY AND MAINLY TO THE NORTH.
TEMPERATURES BELOW NORMAL FOR MUCH OF NEXT WEEK.
&&
.AVIATION... /06Z TAF ISSUANCE/
SOME MINOR ADJUSTMENTS TO GOING FORECAST. MAY SEE A SLOWER START
TIME FARTHER EAST...BUT STILL DROP CEILINGS TO MVFR OVER THE
REGION...MOST LIKELY IFR VSBYS. KRWF MAY SEE IFR CONDITIONS INTO HE
AFTERNOON AS HEAVIER SNOW BAND FORECAST ALONG THE MINNESOTA RIVER
VALLEY...PERHAPS INTO SOUTHERN METRO BY LATE AFTERNOON. WILL HAVE TO
MONITOR BAND AS IT WORKS OVER THE DAKOTAS THIS MORNING. SNOW COMING
IN LATE AFTERNOON/EVENING OVER EASTERN TAF SITES...SHOULD TAPER
FARTHER EAST AS WAVE MOVES THROUGH DRY AIR AND WEAKENS A BIT. SNOW
SHOULD END TO THE WEST EARLY EVENING AND AFTER 06Z TO THE
EAST...WITH MVFR CEILINGS REMAINING FOR NOW AHEAD OF THE NEXT
STRONGER SYSTEM FOR SATURDAY. LIGHT WINDS BECOMING MORE
NORTHEAST/EAST AHEAD OF WAVE AND EVENTUALLY SOUTHEAST TO SOUTH ON
SATURDAY.
KMSP...ONLY MINOR ADJUSTMENT TO TIMING OF SNOW. SHOULD MOVE IN BY
22Z AND EXIT AFTER 06Z2. IFR VSBYS IN HEAVIER SNOW THIS
EVENING...THEN IMPROVING LATE. MAYBE AN INCH ACCUMULATION.
LIGHT WINDS BECOMING NORTHEAST TO EAST DURING THE DAY AND SOUTHEAST
INTO SATURDAY.
/OUTLOOK FOR KMSP/
SAT...MVFR CIGS ENDING IN THE MORNING...THEN VFR. MVFR/IFR CIGS/VIS
DEVELOPING OVERNIGHT WITH SN. WINDS SE AT 10KTS.
SUN...SN ENDING IN THE AFTERNOON...2-4 IN POSSIBLE. MVFR/IFR
CIGS/VIS IN MORNING. MVFR CIGS AFTERNOON. WINDS BCMG NW
20G30KTS.
MON...MVFR CIGS EARLY...BECOMING VFR IN AFTERNOON. WINDS NW 15KTS
IN MORNING...BCMG SW AT 5 KTS IN AFTERNOON.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT CST TONIGHT
FOR BLUE EARTH-BROWN-CHIPPEWA-FARIBAULT-LAC QUI PARLE-LE
SUEUR-MARTIN-NICOLLET-REDWOOD-RENVILLE-SIBLEY-WASECA-
WATONWAN-YELLOW MEDICINE.
WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY
AFTERNOON FOR ANOKA-BENTON-CHIPPEWA-CHISAGO-DOUGLAS-ISANTI-
KANABEC-KANDIYOHI-LAC QUI PARLE-MCLEOD-MEEKER-MILLE LACS-
MORRISON-POPE-REDWOOD-RENVILLE-SHERBURNE-STEARNS-STEVENS-
SWIFT-TODD-WRIGHT-YELLOW MEDICINE.
WI...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY
EVENING FOR BARRON-CHIPPEWA-POLK-RUSK.
&&
$$
RAH/DE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
411 AM CST FRI DEC 7 2012
.DISCUSSION...
PLENTY OF CONCERNS THIS MORNING WITH TWO WEATHER SYSTEMS MOVING
THROUGH FROM TODAY THROUGH SUNDAY.
THE FIRST IS A MID LEVEL LOW APPROACHING CENTRAL SD EARLY THIS
MORNING. THIS FEATURE IS PROGGED TO MOVE EAST AND PASS ACROSS
SOUTHERN MN THIS EVENING. ACCOMPANYING THE LOW IS A FAIRLY STRONG
BAND OF FRONTOGENESIS AND OMEGA AT -15 DEG C. THE PROBLEM IS THE
FORCING AND MODEL QPF...ESPECIALLY FROM THE GFS...ARE NOT IN SYNC.
IN ADDITION...THERE IS GOOD CONSENSUS ON A PV MAX MOVING ACROSS
SOUTHERN MN ALONG WITH A 120M HEIGHT FALL CENTER. RAP GUIDANCE
POINTS TO SW AND SOUTH CENTRAL MN FOR THE MOST QPF WHICH AGREES
MUCH BETTER WITH THE FORCING. PRECIP AMOUNTS ARE IN THE .10 TO .25
INCH RANGE WITH THE MOST IN OUR FAR SW MN COUNTIES. THE NAM AND
GFS ARE SIMILAR BUT MUCH FARTHER NORTH. FOLLOWING THE FORCING
SEEMS TO BE THE MOST CORRECT THING TO DO AND THIS WOULD PLACE NEAR
ADVISORY SNOWFALL OVER SW AND PARTS OF SOUTH CENTRAL MN DURING THE
AFTERNOON AND EVENING. THE TREND ON THIS WEATHER SYSTEM OVER THE
PAST TWO NIGHTS HAS BEEN GETTING STRONGER AND TAKING LONGER TO
WEAKEN DURING THE OVERNIGHT HOURS. THERE IS ALSO QUITE THE SNOW
BAND IN WESTERN/CENTRAL SD NORTH OF I-90. THEREFORE..USED
FORECASTER DISCRETION AND ISSUED A WINTER WEATHER ADVISORY FROM
WEST CENTRAL INTO SOUTH CENTRAL MN FOR THIS AFTERNOON AND EVENING.
WE CURRENTLY HAVE 2 TO 2.5 INCHES IN THE ADVISORY AREA...BUT
CONCERNED AMOUNTS MAY BE HIGHER IN THE BAND OF MID LEVEL -FN
VECTOR DIVERGENCE. STILL HAVE SNOW SPREADING ACROSS THE TWIN
CITIES DURING THE AFTERNOON AND EVENING WITH AMOUNTS UP TO ONE
INCH.
THE SECOND CONCERN IS A MUCH STRONGER LOW PRESSURE SYSTEM FORECAST
ACROSS THE REGION SATURDAY NIGHT AND SUNDAY. NAM/GFS/ECMWF STILL
SHOW A MID LEVEL LOW PASSING ACROSS CENTRAL MN AND NORTHERN WI
DURING THIS PERIOD. A BAND OF WAA SNOW WILL PRECEDE THE LOW WITH
DEFORMATION SNOW CONTINUING FROM WEST CENTRAL MN INTO THE
ARROWHEAD ON SUNDAY. THE TOP THREE CIPS ANALOGS ALL HAD 6+ INCHES
OF SNOW ACROSS CENTRAL MN WITH A FOOT OR MORE FOR THE NORTH. THE
TREND ON THIS WEATHER SYSTEM OVER THE PAST FEW NIGHT IS FARTHER
SOUTH WITH THE SFC/MID LEVEL LOW PRESSURE. THIS SYSTEM IS
ACCOMPANIED BY A VERY STRONG PV BOOT SATURDAY NIGHT AND SUNDAY
POINTING INTO WEST CENTRAL AND NORTHERN AREAS OF MN. THE SURFACE
GRADIENT THAT DEVELOPS OVER WESTERN MN SUNDAY MORNING IS ALARMING.
BUFKIT NAM/GFS PROFILE DATA FOR KMOX SHOW WINDS JUST OFF THE
SURFACE IN THE 25-29 KNOT RANGE WITH TOP OF THE CHANNEL IN THE
38-43 KNOT RANGE. DEPENDING ON HOW MUCH SNOW FALLS...AND IF THE
WINDS VERIFY...THIS COULD END UP BEING A BLIZZARD FOR PARTS OF THE
WEST ON SUNDAY. TEMPERATURES WILL ALSO BE STEADY OR FALLING IN
THE TEENS WITH BELOW ZERO TEMPERATURES EXPECTED SUNDAY NIGHT.
AFTER QUITE A BIT OF COLLABORATION WITH KDLH...KARX AND KABR...WE
FELT IT WAS PRUDENT TO ISSUE A WINTER STORM WATCH FOR SATURDAY
NIGHT AND SUNDAY. CURRENT SNOW ACCUMULATION GRIDS ARE IN THE 5 TO
7 INCH RANGE ACROSS CENTRAL MN AND PARTS OF WEST CENTRAL WI.
CURRENTLY HAVE 4 TO 5 INCHES FOR THE TWIN CITIES.
LITTLE TIME SPENT ON LONGER TERM GRIDS WITH THE CRH EXTEND
ACCEPTED. A QUICK GLANCE FOR THE MONDAY THROUGH THURSDAY PERIOD
SHOWS ONLY WEAK WEATHER SYSTEM PASSING BY AND MAINLY TO THE NORTH.
TEMPERATURES BELOW NORMAL FOR MUCH OF NEXT WEEK.
&&
.AVIATION... /06Z TAF ISSUANCE/
MAIN CHANGE WITH 06Z TAFS...IS THAT 00Z NAM/GFS ALONG WITH LAST
FEW RUNS OF THE HRRR IS STARTING TO INCREASE CONFIDENCE IN -SN
OCCURRING AT ALL TERMINALS. TIMING IN TAFS STILL LOOKS GOOD AS WELL.
GFS/NAM ALONG WITH THE HRRR SEEM TO BE HONING IN ON A BAND OF -SN
COMING OUT OF CENTRAL SODAK...THEN DUE EAST ACROSS THE MPX AREA FRI
AFTERNOON/EVENING. AXN/STC MAY BE JUST NORTH OF THE HEAVIEST
SNOW...BUT A QUICK 1-3 INCHES IS LOOKING MORE PLAUSIBLE FOR RWF
AND MSP. FOR WI...MODELS CONTINUE TO SHOW FORCING AND SNOW WANING
AS THINGS GET INTO WI...SO LEFT VIS RESTRICTIONS ANT RNH/EAU AT
MVFR. CIGS WILL BE SLOW TO DESCEND...BUT BY FRIDAY NIGHT...925-850
RH FROM THE GFS/NAM ALONG WITH SREF PROBS FOR CIGS LESS THAN 3K FT
WOULD INDICATE THAT A BAND OF IFR/MVFR MAY GET HUNG UP ACROSS
MN...SO DID TREND CIGS DOWNWARD...ESPECIALLY FOR AXN/RWF.
KMSP...290/295K ISENTROPIC SFCS ALONG WITH MID-LEVEL FGEN WOULD
SAY SNOW COULD START AS EARLY AS 18Z AT MSP...BUT BEST FORCING
STILL WAITS UNTIL 00Z TO BRING IN BEST FORCING...SO BROUGHT IN IFR
VSBYS THEN. LOOKS LIKE THE EVENING RUSH COULD SEE 1-3 INCHES OF
SNOW IF CURRENT GFS/NAM PANS OUT. FOR WINDS...THEY WILL BE LIGHT
WITH HIGH PRESSURE SLIDING BY THROUGH THE PERIOD WITH JUST A
GRADUAL VEERING OF WINDS FROM NW TO SE THROUGH THE PERIOD.
DIRECTIONS LOOK TO CROSS AN 040 DIRECTION AROUND 3Z.
/OUTLOOK FOR KMSP/
SAT...MVFR CIGS ENDING MID MORNING...THEN VFR. MVFR/IFR CIGS/VIS
DEVELOPING OVERNIGHT WITH SN. WINDS SE AT 10KTS.
SUN...SN ENDING IN MORNING...1-3 IN POSSIBLE. MVFR/IFR CIGS/VIS IN
MORNING. MVFR CIGS AFTERNOON. WINDS BCMG NW 20G30KTS.
MON...MVFR CIGS EARLY...BECOMING VFR IN AFTERNOON. WINDS NW 15KTS
IN MORNING...BCMG SW AT 5 KTS IN AFTERNOON.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT CST TONIGHT
FOR BLUE EARTH-BROWN-CHIPPEWA-FARIBAULT-LAC QUI PARLE-LE
SUEUR-MARTIN-NICOLLET-REDWOOD-RENVILLE-SIBLEY-WASECA-
WATONWAN-YELLOW MEDICINE.
WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY
AFTERNOON FOR ANOKA-BENTON-CHIPPEWA-CHISAGO-DOUGLAS-ISANTI-
KANABEC-KANDIYOHI-LAC QUI PARLE-MCLEOD-MEEKER-MILLE LACS-
MORRISON-POPE-REDWOOD-RENVILLE-SHERBURNE-STEARNS-STEVENS-
SWIFT-TODD-WRIGHT-YELLOW MEDICINE.
WI...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY
EVENING FOR BARRON-CHIPPEWA-POLK-RUSK.
&&
$$
RAH/MPG
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
524 AM CST FRI DEC 7 2012
.UPDATE...
.AVIATION...
VFR IS EXPECTED MOST AREAS TODAY AND TONIGHT.
THE GENERAL MODEL CONSENSUS SUGGESTS MVFR CIGS WILL DEVELOP THIS
AFTERNOON ACROSS NORTHERN NEB...GENERALLY ALONG AND NORTH OF
HIGHWAY 20. THIS RESTRICTION IS ASSOCIATED WITH A COLD FRONT
FORECAST TO DROP THROUGH THE FCST AREA. THE RAP MODEL AND OTHERS
SUGGEST THE MVFR CIGS WILL SPREAD EAST AND SOUTH THIS AFTN AND
THIS EVENING. THE PROBLEM IN THE MODELS REVOLVES AROUND THE
DURATION OF THE MVFR. SO AS A GENERAL GUIDELINE...CEILINGS ARE
EXPECTED TO IMPROVE TO VFR ALL AREAS TONIGHT...BETWEEN 01Z-06Z.
&&
.PREV DISCUSSION... /ISSUED 245 AM CST FRI DEC 7 2012/
SYNOPSIS...
AT 08Z...SURFACE ANALYSIS SHOWED LOW PRESSURE CENTERED OVER
SOUTHEAST WYOMING WITH A STATIONARY FRONT EXTENDING INTO EASTERN
COLORADO. AN INVERTED TROUGH EXTENDED FROM THE LOW CENTER TO
NORTHEAST SOUTH DAKOTA. IN THE UPPER LEVELS...WATER VAPOR IMAGERY
INDICATED A BROAD STREAM OF MID-LEVEL MOISTURE COMING ACROSS THE
ROCKIES FROM THE PACIFIC NORTHWEST. IN THE WEST...AN UPPER TROUGH
WAS DIGGING ALONG THE CALIFORNIA COAST. RADAR SHOWED SOME ECHOES
MOVING ACROSS NORTHERN NEBRASKA JUST SOUTH AND EAST OF THE INVERTED
TROUGH.
DISCUSSION...
AS AN OVERVIEW...THE STATIONARY FRONT ALONG THE EASTERN SLOPES
OF THE ROCKIES WILL BE THE PLAYER IN THE FORECAST THROUGH SUNDAY AS
IT OSCILLATES ACROSS THE HIGH PLAINS. WITH EACH OSCILLATION...THE
DYNAMICS IN THE AREA BECOME SUFFICIENT FOR PRODUCING SIGNIFICANT
LIFT.
SHORT RANGE...TODAY AND TONIGHT.
AS THE FRONT ALONG THE EASTERN SLOPE MAKES ITS WAY NORTHEASTWARD
ACROSS NEBRASKA...SIGNIFICANT ISENTROPIC UPGLIDE DEVELOPS EARLY THIS
MORNING AS INDICATED BY MOISTURE TRANSPORT VECTORS ON THE 290K AND
295K SURFACES. THE SOURCE OF THE MOISTURE TRANSPORT IS THE NORTHWEST
U.S. AND THE EXTREME SOUTHWEST. AS A RESULT...THE WESTERN MOST AIR
WILL BE DRY WITH SATURATION DEFICITS OF 50-120MB IN THE 290-300K
LAYER. IT SATURATES NEAR A MERRIMAN-THEDFORD-LEXINGTON LINE. IN
FACT...CURRENT RADAR ECHOES IN NORTHERN NEBRASKA INDICATE THAT
SATURATION HAS BEEN REACHED IN THE LIFTED LAYER. AT THIS TIME...IT
APPEARS THAT SOME CHANCE OF LIGHT SNOW IS APPROPRIATE THIS MORNING.
ACCUMULATIONS WILL BE LIMITED BECAUSE THE COVERAGE IS NOT HIGH.
NORTHEAST-SOUTHWEST CROSS SECTIONS INDICATE A TEMPERATURE PROFILE
FAVORABLE FOR SNOW THIS MORNING. HOWEVER...THE SAME CROSS SECTIONS
INDICATE A SHALLOW VERY DRY LAYER NEAR THE SURFACE...SO THE NEAR
SURFACE LAYER WILL NEED TO MOISTEN BEFORE PRECIPITATION CAN
REACH THE SURFACE. WITH THE MIXING RATIO OF 2-3G/KG...NOT A LOT OF
MOISTURE IS AVAILABLE AND THE SYSTEM IS LIKELY TO BE OUT OF CENTRAL
AND SOUTHWEST NEBRASKA BEFORE THAT SATURATION CAN OCCUR.
THEREFORE...THE CHANCES OF PRECIPITATION TODAY WILL BE VERY LOW IF
NOT COMPLETELY NON-EXISTENT FOR CENTRAL AND SOUTHWEST NEBRASKA.
BEHIND THE WARM FRONT...A COLD FRONT PLUNGES THROUGH NORTH
CENTRAL THROUGH SOUTHWEST NEBRASKA BY EARLY THIS AFTERNOON.
ALTHOUGH SYSTEM RELATIVE ISENTROPIC LIFT IS SIGNIFICANT AND ENHANCED
WITH FRONTOGENETIC FORCING...THE AIR BEING LIFTED IS DRY AND
PRECIPITATION IS UNLIKELY.
MEDIUM RANGE...SATURDAY THROUGH SUNDAY NIGHT.
WE ARE STILL GETTING SOME MIXED SIGNALS REGARDING THE SYSTEM
SATURDAY AND SUNDAY FROM THE MEDIUM RANGE MODEL OUTPUT.
FOR A BRIEF PERIOD SATURDAY MORNING...THE FRONT RETURNS TO SOUTH
CENTRAL AND SOUTHWEST NEBRASKA AND SOME ISENTROPIC UPGLIDE IS
INDICATED ONCE AGAIN UNTIL THE COLD FRONT PLUNGES THROUGH. THE COLD
FRONT IS VERY STRONG AND SYSTEM-RELATIVE ISENTROPIC LIFT WILL ALSO
BE STRONG WITH FRONTOGENETIC ENHANCEMENT LIKELY. THE NORTH-SOUTH
CROSS SECTION THROUGH OGALLALA INDICATES AN UNSTABLE LAYER 288-297K
AND THE SATURATED AIR IS LIFTED INTO THE DENDRITIC LAYER 291-294K.
THEREFORE...THERE WILL BE NO DIFFICULTY FOR SNOW CRYSTAL FORMATION.
HOWEVER...ONCE AGAIN...THE LOWEST LAYERS ARE VERY DRY. STILL...
LATENT HEAT ABSORPTION COULD COOL THE LOWEST LAYERS TO NEAR
SATURATION AND ALLOW SNOW TO REACH THE SURFACE. THE BOTTOM LINE IS
THAT WE DO NOT HAVE HIGH CONFIDENCE IN THE OCCURRENCE OF
PRECIPITATION AND...IF IT DOES OCCUR...AMOUNTS WILL BE LOW.
WITH THE PASSAGE OF THE FRONT...WINDY CONDITIONS ARE EXPECTED. A
STRONG PRESSURE GRADIENT IS INDICATED AND STRONG COLD ADVECTION WILL
KEEP THE SURFACE TO 2KM LAYER WELL MIXED.
EXTENDED...SUNDAY NIGHT THROUGH THURSDAY.
AFTER THE FRONT PUSHES THROUGH...NORTH-NORTHWEST FLOW ALOFT WILL
STEER COLD AIR MASSES ONTO THE HIGH WITH A TRAJECTORY FROM NORTHERN
BRITISH COLUMBIA AND THE SOUTHERN YUKON SUNDAY NIGHT THROUGH
TUESDAY. IF ANY SNOW OCCURS SATURDAY AND SUNDAY...TEMPERATURES
MONDAY MORNING AND TUESDAY MORNING COULD BE THE COLDEST OF THE
SEASON. AT THIS TIME...WE ARE NOT GOING TO SINGLE DIGITS BECAUSE OF
THE LACK OF CONFIDENCE THAT SNOW WILL OCCUR.
SOME WARMING CAN BE EXPECTED WEDNESDAY AND THURSDAY THOUGH NOT
ANYWHERE NEAR THE HIGH TEMPERATURES THAT WERE OBSERVED LAST WEEK.
AVIATION...
VFR IS EXPECTED MOST AREAS TODAY AND TONIGHT.
THE GENERAL MODEL CONSENSUS SUGGESTS MVFR CIGS WILL DEVELOP THIS
AFTERNOON ALONG AND NORTH OF HIGHWAY 20. THIS RESTRICTION IS
ASSOCIATED WITH A COLD FRONT FORECAST TO DROP THROUGH THE FCST AREA.
CEILINGS ARE EXPECTED TO IMPROVE TO VFR ALL AREAS TONIGHT...BETWEEN
01Z-06Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1010 AM EST FRI DEC 7 2012
.SYNOPSIS...
A WARM FRONT WILL BRING RAIN TO MUCH OF THE REGION TODAY. AREAS
OF FREEZING RAIN ARE LIKELY IN THE HIGHER ELEVATIONS UNTIL NOON ACROSS
NORTHEAST PENNSYLVANIA, THE SOUTHERN TIER AND CATSKILLS. THIS WILL
MARK THE BEGINNING OF A RATHER UNSETTLED PERIOD WITH SCATTERED
SHOWERS POSSIBLE EACH DAY AS SEVERAL DISTURBANCES INTERACT WITH
THE STALLED FRONT. TEMPERATURES THROUGH THE WEEKEND WILL REMAIN
ABOVE NORMAL AS ANY COLD AIR REMAINS DISPLACED WELL TO OUR WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
10 AM UPDATE...BASED ON LOCAL MESONET OBS ACROSS NE PA AND PARTS OF
THE SOUTHERN TIER AND WESTERN CATSKILLS DECIDED TO EXTEND THE FREEZING
RAIN ADV UNTIL MIDDAY. THE HIGHER ELEVATIONS PRIMARILY ABOVE 1200 FT
AND THE WESTERN CATSKILLS INCLUDING SULLIVAN COUNTY WILL SEE THE
MOST FREEZING RAIN DURING THE NEXT COUPLE OF HOURS. BY EARLY
AFTERNOON, COMBINATION OF WARMING ALOFT AND SFC TEMPS RISING
ABOVE THE FREEZING MARK WILL END THE FREEZING RAIN THREAT.
830 AM UPDATE...ISSUED FREEZING RAIN ADVISORY FOR TIOGA, BROOME,
CHENANGO AND OTSEGO COUNTIES UNTIL 11 AM. LIGHT PRECIP IS NOW
SPREADING ACROSS THE ABOVE MENTIONED AREAS WITH TEMPS NEAR
FREEZING AND DEW POINTS IN THE LOWER TO MIDDLE 20S. THE LOW
DEW POINTS WILL ALLOW TEMPS TO REMAIN STEADY OR DROP SLIGHTLY AS THE
LIGHT PRECIP BEGINS WITH AREAS OF FREEZING RAIN LIKELY UNTIL LATE
MORNING ESPECIALLY AT THE HIGHER ELEVATIONS. BY LATE MORNING WARM
LAYER ALOFT AND DIURNAL HEATING WILL END THE THREAT FOR FREEZING
RAIN.
650 AM UPDATE...
BASED ON TEMP TRENDS FROM LOCAL MESONET OBSERVATIONS...HAVE
ELECTED TO GO WITH AN FREEZING RAIN ADVISORY FOR ALL OF NE PA AND
THE CATSKILLS OF EASTERN NY. AS PRECIP CONTINUES TO MOVE
IN...CANNOT RULE OUT VERY LIGHT ICE ACCUMULATIONS FOR ELEVATIONS
GRATER THAN 1000 FEET. FOR NOW HAVE HELD OFF FOR THE CENTRAL AND
EASTERN SOUTHERN TIER AS BULK OF INITIAL BATCH OF RA WILL LIKELY
PASS JUST TO THE SOUTH. AFTER THIS...TEMPS SHOULD WARM ABOVE
FREEZING HOPEFULLY NEGATING ANY FREEZING RAIN CONCERNS FOR THESE
AREAS. NO OTHER SIGNIFICANT CHANGES NEEDED AT THE PRESENT TIME.
PREVIOUS NEAR TERM DISCUSSION...
MAIN CONCERN IN THE NEAR TERM CONTINUES TO BE APPROACHING FRONTAL
WAVE AND ASSOCIATED PRECIP LATER THIS MORNING. LATEST REGIONAL
RADAR IMAGES SHOWING LEADING EDGE OF RAIN NOW EAST OF PIT AND
WORKING TOWARDS JST IN SW PA. AHEAD OF THIS PRECIP...A SUBSTANTIAL
AMOUNT OF DRY AIR REMAINS IN PLACE AS EVIDENCED BY 00Z PIT AND BUF
RAOBS. PRECIP IS BEING FORCED LARGELY BY ISENTROPIC ASCENT ALONG
THE 285-295 THETA SURFACES AS INCREASING WINDS AT THE 925 AND
850-MB LEVELS ASCEND THE APPROACHING FRONTAL BOUNDARY. WITH THE
AMOUNT OF DRY AIR IN PLACE...HAVE ELECTED TO TRIM BACK TIMING OF
PRECIP ARRIVAL TIME FROM THE TWIN TIERS AND POINTS SOUTH. IT NOW
APPEARS THAT PRECIP WILL NOT MAKE INTO THE CWA BEFORE 12Z AS
SUFFICIENT TIME WILL BE REQUIRED TO MOISTEN THE ATMOSPHERIC
COLUMN.
THE ABOVE SAID...MAIN ATTENTION CONTINUES TO FOCUS ON FZRA
POTENTIAL AS INITIAL BATCH OF PRECIP MOVES IN. CLOSE INSPECTION OF
BOTH RR AND WRF THETA SURFACES AND MODEL CONDENSATION PRESSURE
DEFICITS REVEALS APPROPRIATE SATURATION ALONG THE 285 SFC WILL NOT
OCCUR UNTIL 12-13Z AT THE EARLIEST. BY THIS TIME...DIURNAL TEMPS
SHOULD BEGIN REBOUNDING AS DAYTIME HEATING COMMENCES WHICH SHOULD
ONLY RESULT IN A VERY BRIEF PERIOD WHERE SFC TEMPS MAY BE COLD
ENOUGH TO SUPPORT FZRA ALONG THE ELEVATED SURFACES OF THE NORTHERN
TIER AND LOWER WYOMING VALLEY REGIONS OF NE PA.
BEYOND THIS...RA WILL GRADUALLY OVERSPREAD THE REGION THROUGH THE
MORNING AND AFTERNOON HRS. UP NORTH...PRECIP WILL LIKELY HOLD OFF
UNTIL EARLY AFTERNOON AFTER WHICH...WEAK SHORTWAVE ENERGY RIDING
ALONG THE FRONT SHOULD EVENTUALLY ALLOW PRECIP TO EXTEND AS FAR
NORTH AS THE SYR AND RME AREAS. RAINFALL AMOUNTS THROUGH THE DAY WILL
LIKELY REMAIN UNDER 2 TENTH OF AN INCH AT MOST LOCATIONS...WITH
EVEN LOWER AMOUNTS EXPECTED ACROSS THE NORTHERN FINGER LAKES AND
WESTERN MOHAWK VALLEY AS MAX FRONTAL FORCING REMAINS SOUTH. HIGH
TEMPS WILL TOP OUT IN LOWER 40S ACROSS THE NORTHERN FINGER LAKES
AND LAKE PLAIN...WITH MIDDLE TO UPPER 30S DOMINATE ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
FAIRLY ACTIVE PERIOD CONTINUING TO TAKE SHAPE THROUGH THE UPCOMING
WEEKEND AS THE NEXT IN A SERIES OF SFC LOWS LIFTS NORTH ALONG A
STALLED FRONT TO OUR WEST BEGINNING TONIGHT. THAT SAID...RA ACROSS
THE REGION SHOULD BECOME A LITTLE BIT MORE ORGANIZED INITIALLY
THIS EVENING AS SFC LOW LIFTS NORTH FROM THE LWR OHIO VLY INTO THE
LWR GREAT LAKES. AS THIS OCCURS...FORCING CONTRIBUTIONS FROM BOTH
THE POLAR AND SUBTROPICAL JETS WILL TRANSCEND ACROSS THE REGION
WITH ADDITIONAL FORCING ARRIVING FROM CONTINUED ISENTROPIC ASCENT
ALONG THE PREVIOUSLY MENTIONED WARM FRONT. THERMAL PROFILES FROM
ACROSS THE REGION INDICATE SFC TEMPS WILL REMAIN ABOVE FREEZING AS
WARM AIR ADVECTION CONTINUES. THIS SHOULD KEEP ANY PRECIP IN
LIQUID FORM.
SFC LOW PROGGED TO PASS TO OUR WEST ON SATURDAY WITH INCREASING
SOUTHWESTERLY FLOW FINALLY ALLOWING WARM FRONT TO LIFT NORTH
THROUGH THE ENTIRE CWA. AS A RESULT...EXPECT A WARMER DAY WITH
TEMPS TOPPING OUT IN THE UPPER 40S TO LOWER 50S ACROSS MUCH OF THE
AREA. WITH BEST FORCING FOR ASCENT ARRIVING FROM A NORTHERN STREAM
SHORTWAVE ACROSS THE UPPER GREAT LAKES...BEST CHANCES FOR
ORGANIZED PRECIP WILL LIKELY REMAIN NORTH AND WEST OF OUR AREA.
DESPITE THIS HOWEVER...SHORT TERM MODELS INDICATE A DEVELOPING SECONDARY
LOW OFF THE NJ COAST THROUGH THE DAY WHICH COMBINED WITH A WEAKER
SHORTWAVE IMPULSE PASSING OVERHEAD SHOULD KEEP THE CHC FOR SHWRS
ACROSS THE AREA THROUGH THE DAY. MAIN LOW EXPECTED TO PASS TO OUR
NORTH OVERNIGHT WHICH WILL SEND A COLD FRONT SOUTH ACROSS THE FCST
AREA. MODELS AGREE A QUICK COOL DOWN WILL OCCUR AFTER PASSAGE WITH
850-MB TEMPS QUICKLY FALLING TO -4C ACROSS THE FAR NORTH. HIGHLY
SHEARED FLOW COMBINED WITH THE INFLUX OF DRY AIR AND ONLY MARGINAL
TEMP DIFFERENCES WILL NEGATE ANY LAKE RESPONSE AND THUS HAVE DRIED
THINGS OUT FROM NORTH TO SOUTH OVERNIGHT EARLY SUN.
NEXT MORE POTENT WAVE TO LIFT NORTH FROM THE OHIO VLY ON SUN WHICH
WILL ONCE AGAIN LIFT THE FRONT BACK NORTH THROUGH BEGINNING SUN
NGT. AS SUCH...EXPECT INCREASING CHANCES FOR RAIN ONCE AGAIN SUN
AFTERNOON AND EVENING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
430 AM UPDATE...
NO CHGS NEEDED TO LONG TERM AT THIS TIME AS FRONT MVS THRU MON
EVNG WITH LKLY RAIN SHOWERS. NW FLOW KICKS IN FOLLOWING FROPA TO RESULT
IN LK EFFECT PCPN. BOTH 12Z AND NOW 00Z EC INDICATE DVLPNG SFC
LOPRES RIDING UP ALONG SFC BNDRY JUST OFF THE EAST COAST BY EARLY
WEEK, ALTHO NO OTHER MED RANGE MODELS HV THIS FEATURE.
PREV DISCUSSION BLO...
MEDIUM RANGE MODELS CONTINUE TO SHOW FAIR AGREEMENT THROUGH THE
EXTENDED PERIOD.
SUNDAY NIGHT THROUGH MONDAY, SFC LOW PRES WILL TRACK FROM THE OHIO
VALLEY NORTHEAST ACROSS LAKE ERIE INTO NEARBY SOUTHERN ONTARIO.
WILL CARRY LIKELY POPS BOTH PERIODS WITH RAIN LIKELY SUNDAY NIGHT
FOLLOWED BY RAIN SHOWERS ON MONDAY AS TRAILING COLD FRONT CROSSES
AREA MONDAY AFTERNOON AND EVENING. THROUGH MONDAY EVENING TEMPS
WILL REMAIN WARM ENOUGH FOR JUST LIQUID PRECIP TO FALL. MONDAY
NIGHT AS TEMPS LOWER UNDER CAA AND NORTHWEST FLOW, A WEAK LAKE
RESPONSE MAY OCCUR INTO TUESDAY.
TUESDAY NIGHT THROUGH THURSDAY, LOOKS DRY WITH SFC HIGH PRES
STRETCHING FROM THE MID ATLANTIC REGION INTO NEW ENGLAND.
TEMPS THROUGH THE PERIOD WILL START WELL ABOVE NORMAL THEN FALL TO
SEASONAL LEVELS TUESDAY AND WEDNESDAY BEFORE MODERATING AGAIN ON
THURSDAY.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
12Z UPDATE...
VFR INITIALLY WILL GIVE WAY TO MVFR CIGS LATE THIS MORNING. AS
PCPN MOVES FROM SOUTH TO NORTH IT WILL BRING MVFR VSBYS TO
TERMINALS AFTER 18Z. LIGHT RAIN WILL CONTINUE THROUGH THE DAY WITH
MVFR CONDITIONS EXPECTED. HIGHER TERMINALS WILL LIKELY SEE THESE
CIGS DECREASE TO IFR AFTER 05Z AS LOW LEVEL MOISTURE REMAINS
ENTRENCHED ACROSS THE AREA.
SOUTH WINDS AROUND 5 KTS WILL INCREASE TO NEAR 10KTS THIS
AFTERNOON THEN DIMINISH TO LGT/VRB AFTER 06Z.
OUTLOOK...
SATURDAY...MVFR IN SHRA.
SATURDAY NIGHT/SUNDAY MORNING...PRIMARILY VFR.
SUNDAY AFTERNOON THROUGH MONDAY EVENING...RESTRICTIONS EXPECTED IN
RAIN.
TUESDAY...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR PAZ038>040-043-
044-047-048-072.
NY...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR NYZ045-046-
055>057-062.
&&
$$
SYNOPSIS...CMG/RRM
NEAR TERM...CMG/RRM
SHORT TERM...CMG
LONG TERM...PVN/RRM
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
837 AM EST FRI DEC 7 2012
.SYNOPSIS...
AN APPROACHING WARM FRONT WILL LEAD TO SCATTERED SHOWERS ACROSS
THE REGION TODAY. AREAS OF FREEZING RAIN ARE LIKELY IN THE HIGHER
ELEVATIONS THROUGH LATE MORNING ACROSS NORTHEAST PENNSYLVANIA, THE
SOUTHERN TIER AND CATSKILLS. THIS WILL MARK THE BEGINNING OF A
RATHER UNSETTLED PERIOD WITH SCATTERED SHOWERS POSSIBLE EACH DAY
AS SEVERAL DISTURBANCES INTERACT WITH THE STALLED FRONT.
TEMPERATURES THROUGH THE WEEKEND WILL REMAIN ABOVE NORMAL AS ANY
COLD AIR REMAINS DISPLACED WELL TO OUR WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
830 AM UPDATE...ISSUED FREEZING RAIN ADVISORY FOR TIOGA, BROOME,
CHENANGO AND OTSEGO COUNTIES UNTIL 11 AM. LIGHT PRECIP IS NOW
SPREADING ACROSS THE ABOVE MENTIONED AREAS WITH TEMPS NEAR
FREEZING AND DEW POINTS IN THE LOWER TO MIDDLE 20S. THE LOW
DEW POINTS WILL ALLOW TEMPS TO REMAIN STEADY OR DROP SLIGHTLY AS THE
LIGHT PRECIP BEGINS WITH AREAS OF FREEZING RAIN LIKELY UNTIL LATE
MORNING ESPECIALLY AT THE HIGHER ELEVATIONS. BY LATE MORNING WARM
LAYER ALOFT AND DIURNAL HEATING WILL END THE THREAT FOR FREEZING
RAIN.
650 AM UPDATE...
BASED ON TEMP TRENDS FROM LOCAL MESONET OBSERVATIONS...HAVE
ELECTED TO GO WITH AN FREEZING RAIN ADVISORY FOR ALL OF NE PA AND
THE CATSKILLS OF EASTERN NY. AS PRECIP CONTINUES TO MOVE
IN...CANNOT RULE OUT VERY LIGHT ICE ACCUMULATIONS FOR ELEVATIONS
GRATER THAN 1000 FEET. FOR NOW HAVE HELD OFF FOR THE CENTRAL AND
EASTERN SOUTHERN TIER AS BULK OF INITIAL BATCH OF RA WILL LIKELY
PASS JUST TO THE SOUTH. AFTER THIS...TEMPS SHOULD WARM ABOVE
FREEZING HOPEFULLY NEGATING ANY FREEZING RAIN CONCERNS FOR THESE
AREAS. NO OTHER SIGNIFICANT CHANGES NEEDED AT THE PRESENT TIME.
PREVIOUS NEAR TERM DISCUSSION...
MAIN CONCERN IN THE NEAR TERM CONTINUES TO BE APPROACHING FRONTAL
WAVE AND ASSOCIATED PRECIP LATER THIS MORNING. LATEST REGIONAL
RADAR IMAGES SHOWING LEADING EDGE OF RAIN NOW EAST OF PIT AND
WORKING TOWARDS JST IN SW PA. AHEAD OF THIS PRECIP...A SUBSTANTIAL
AMOUNT OF DRY AIR REMAINS IN PLACE AS EVIDENCED BY 00Z PIT AND BUF
RAOBS. PRECIP IS BEING FORCED LARGELY BY ISENTROPIC ASCENT ALONG
THE 285-295 THETA SURFACES AS INCREASING WINDS AT THE 925 AND
850-MB LEVELS ASCEND THE APPROACHING FRONTAL BOUNDARY. WITH THE
AMOUNT OF DRY AIR IN PLACE...HAVE ELECTED TO TRIM BACK TIMING OF
PRECIP ARRIVAL TIME FROM THE TWIN TIERS AND POINTS SOUTH. IT NOW
APPEARS THAT PRECIP WILL NOT MAKE INTO THE CWA BEFORE 12Z AS
SUFFICIENT TIME WILL BE REQUIRED TO MOISTEN THE ATMOSPHERIC
COLUMN.
THE ABOVE SAID...MAIN ATTENTION CONTINUES TO FOCUS ON FZRA
POTENTIAL AS INITIAL BATCH OF PRECIP MOVES IN. CLOSE INSPECTION OF
BOTH RR AND WRF THETA SURFACES AND MODEL CONDENSATION PRESSURE
DEFICITS REVEALS APPROPRIATE SATURATION ALONG THE 285 SFC WILL NOT
OCCUR UNTIL 12-13Z AT THE EARLIEST. BY THIS TIME...DIURNAL TEMPS
SHOULD BEGIN REBOUNDING AS DAYTIME HEATING COMMENCES WHICH SHOULD
ONLY RESULT IN A VERY BRIEF PERIOD WHERE SFC TEMPS MAY BE COLD
ENOUGH TO SUPPORT FZRA ALONG THE ELEVATED SURFACES OF THE NORTHERN
TIER AND LOWER WYOMING VALLEY REGIONS OF NE PA.
BEYOND THIS...RA WILL GRADUALLY OVERSPREAD THE REGION THROUGH THE
MORNING AND AFTERNOON HRS. UP NORTH...PRECIP WILL LIKELY HOLD OFF
UNTIL EARLY AFTERNOON AFTER WHICH...WEAK SHORTWAVE ENERGY RIDING
ALONG THE FRONT SHOULD EVENTUALLY ALLOW PRECIP TO EXTEND AS FAR
NORTH AS THE SYR AND RME AREAS. RAINFALL AMOUNTS THROUGH THE DAY WILL
LIKELY REMAIN UNDER 2 TENTH OF AN INCH AT MOST LOCATIONS...WITH
EVEN LOWER AMOUNTS EXPECTED ACROSS THE NORTHERN FINGER LAKES AND
WESTERN MOHAWK VALLEY AS MAX FRONTAL FORCING REMAINS SOUTH. HIGH
TEMPS WILL TOP OUT IN LOWER 40S ACROSS THE NORTHERN FINGER LAKES
AND LAKE PLAIN...WITH MIDDLE TO UPPER 30S DOMINATE ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
FAIRLY ACTIVE PERIOD CONTINUING TO TAKE SHAPE THROUGH THE UPCOMING
WEEKEND AS THE NEXT IN A SERIES OF SFC LOWS LIFTS NORTH ALONG A
STALLED FRONT TO OUR WEST BEGINNING TONIGHT. THAT SAID...RA ACROSS
THE REGION SHOULD BECOME A LITTLE BIT MORE ORGANIZED INITIALLY
THIS EVENING AS SFC LOW LIFTS NORTH FROM THE LWR OHIO VLY INTO THE
LWR GREAT LAKES. AS THIS OCCURS...FORCING CONTRIBUTIONS FROM BOTH
THE POLAR AND SUBTROPICAL JETS WILL TRANSCEND ACROSS THE REGION
WITH ADDITIONAL FORCING ARRIVING FROM CONTINUED ISENTROPIC ASCENT
ALONG THE PREVIOUSLY MENTIONED WARM FRONT. THERMAL PROFILES FROM
ACROSS THE REGION INDICATE SFC TEMPS WILL REMAIN ABOVE FREEZING AS
WARM AIR ADVECTION CONTINUES. THIS SHOULD KEEP ANY PRECIP IN
LIQUID FORM.
SFC LOW PROGGED TO PASS TO OUR WEST ON SATURDAY WITH INCREASING
SOUTHWESTERLY FLOW FINALLY ALLOWING WARM FRONT TO LIFT NORTH
THROUGH THE ENTIRE CWA. AS A RESULT...EXPECT A WARMER DAY WITH
TEMPS TOPPING OUT IN THE UPPER 40S TO LOWER 50S ACROSS MUCH OF THE
AREA. WITH BEST FORCING FOR ASCENT ARRIVING FROM A NORTHERN STREAM
SHORTWAVE ACROSS THE UPPER GREAT LAKES...BEST CHANCES FOR
ORGANIZED PRECIP WILL LIKELY REMAIN NORTH AND WEST OF OUR AREA.
DESPITE THIS HOWEVER...SHORT TERM MODELS INDICATE A DEVELOPING SECONDARY
LOW OFF THE NJ COAST THROUGH THE DAY WHICH COMBINED WITH A WEAKER
SHORTWAVE IMPULSE PASSING OVERHEAD SHOULD KEEP THE CHC FOR SHWRS
ACROSS THE AREA THROUGH THE DAY. MAIN LOW EXPECTED TO PASS TO OUR
NORTH OVERNIGHT WHICH WILL SEND A COLD FRONT SOUTH ACROSS THE FCST
AREA. MODELS AGREE A QUICK COOL DOWN WILL OCCUR AFTER PASSAGE WITH
850-MB TEMPS QUICKLY FALLING TO -4C ACROSS THE FAR NORTH. HIGHLY
SHEARED FLOW COMBINED WITH THE INFLUX OF DRY AIR AND ONLY MARGINAL
TEMP DIFFERENCES WILL NEGATE ANY LAKE RESPONSE AND THUS HAVE DRIED
THINGS OUT FROM NORTH TO SOUTH OVERNIGHT EARLY SUN.
NEXT MORE POTENT WAVE TO LIFT NORTH FROM THE OHIO VLY ON SUN WHICH
WILL ONCE AGAIN LIFT THE FRONT BACK NORTH THROUGH BEGINNING SUN
NGT. AS SUCH...EXPECT INCREASING CHANCES FOR RAIN ONCE AGAIN SUN
AFTERNOON AND EVENING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
430 AM UPDATE...
NO CHGS NEEDED TO LONG TERM AT THIS TIME AS FRONT MVS THRU MON
EVNG WITH LKLY RAIN SHOWERS. NW FLOW KICKS IN FOLLOWING FROPA TO RESULT
IN LK EFFECT PCPN. BOTH 12Z AND NOW 00Z EC INDICATE DVLPNG SFC
LOPRES RIDING UP ALONG SFC BNDRY JUST OFF THE EAST COAST BY EARLY
WEEK, ALTHO NO OTHER MED RANGE MODELS HV THIS FEATURE.
PREV DISCUSSION BLO...
MEDIUM RANGE MODELS CONTINUE TO SHOW FAIR AGREEMENT THROUGH THE
EXTENDED PERIOD.
SUNDAY NIGHT THROUGH MONDAY, SFC LOW PRES WILL TRACK FROM THE OHIO
VALLEY NORTHEAST ACROSS LAKE ERIE INTO NEARBY SOUTHERN ONTARIO.
WILL CARRY LIKELY POPS BOTH PERIODS WITH RAIN LIKELY SUNDAY NIGHT
FOLLOWED BY RAIN SHOWERS ON MONDAY AS TRAILING COLD FRONT CROSSES
AREA MONDAY AFTERNOON AND EVENING. THROUGH MONDAY EVENING TEMPS
WILL REMAIN WARM ENOUGH FOR JUST LIQUID PRECIP TO FALL. MONDAY
NIGHT AS TEMPS LOWER UNDER CAA AND NORTHWEST FLOW, A WEAK LAKE
RESPONSE MAY OCCUR INTO TUESDAY.
TUESDAY NIGHT THROUGH THURSDAY, LOOKS DRY WITH SFC HIGH PRES
STRETCHING FROM THE MID ATLANTIC REGION INTO NEW ENGLAND.
TEMPS THROUGH THE PERIOD WILL START WELL ABOVE NORMAL THEN FALL TO
SEASONAL LEVELS TUESDAY AND WEDNESDAY BEFORE MODERATING AGAIN ON
THURSDAY.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
12Z UPDATE...
VFR INITIALLY WILL GIVE WAY TO MVFR CIGS LATE THIS MORNING. AS
PCPN MOVES FROM SOUTH TO NORTH IT WILL BRING MVFR VSBYS TO
TERMINALS AFTER 18Z. LIGHT RAIN WILL CONTINUE THROUGH THE DAY WITH
MVFR CONDITIONS EXPECTED. HIGHER TERMINALS WILL LIKELY SEE THESE
CIGS DECREASE TO IFR AFTER 05Z AS LOW LEVEL MOISTURE REMAINS
ENTRENCHED ACROSS THE AREA.
SOUTH WINDS AROUND 5 KTS WILL INCREASE TO NEAR 10KTS THIS
AFTERNOON THEN DIMINISH TO LGT/VRB AFTER 06Z.
OUTLOOK...
SATURDAY...MVFR IN SHRA.
SATURDAY NIGHT/SUNDAY MORNING...PRIMARILY VFR.
SUNDAY AFTERNOON THROUGH MONDAY EVENING...RESTRICTIONS EXPECTED IN
RAIN.
TUESDAY...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FREEZING RAIN ADVISORY UNTIL 11 AM EST THIS MORNING FOR PAZ040-
048-072.
FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ038-
039-043-044-047.
NY...FREEZING RAIN ADVISORY UNTIL 11 AM EST THIS MORNING FOR NYZ057-
062.
FREEZING RAIN ADVISORY UNTIL 11 AM EST THIS MORNING FOR NYZ045-
046-055-056.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG/RRM
SHORT TERM...CMG
LONG TERM...PVN/RRM
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
649 AM EST FRI DEC 7 2012
.SYNOPSIS...
AN APPROACHING WARM FRONT WILL LEAD TO SCATTERED SHOWERS ACROSS
THE REGION TODAY. THIS WILL MARK THE BEGINNING OF A RATHER
UNSETTLED PERIOD WITH SCATTERED SHOWERS POSSIBLE EACH DAY AS
SEVERAL DISTURBANCES INTERACT WITH THE STALLED FRONT. TEMPERATURES
THROUGH THE WEEKEND WILL REMAIN ABOVE NORMAL AS ANY COLD AIR
REMAINS DISPLACED WELL TO OUR WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
650 AM UPDATE...
BASED ON TEMP TRENDS FROM LOCAL MESONET OBSERVATIONS...HAVE
ELECTED TO GO WITH AN FREEZING RAIN ADVISORY FOR ALL OF NE PA AND
THE CATSKILLS OF EASTERN NY. AS PRECIP CONTINUES TO MOVE
IN...CANNOT RULE OUT VERY LIGHT ICE ACCUMULATIONS FOR ELEVATIONS
GRATER THAN 1000 FEET. FOR NOW HAVE HELD OFF FOR THE CENTRAL AND
EASTERN SOUTHERN TIER AS BULK OF INITIAL BATCH OF RA WILL LIKELY
PASS JUST TO THE SOUTH. AFTER THIS...TEMPS SHOULD WARM ABOVE
FREEZING HOPEFULLY NEGATING ANY FREEZING RAIN CONCERNS FOR THESE
AREAS. NO OTHER SIGNIFICANT CHANGES NEEDED AT THE PRESENT TIME.
PREVIOUS NEAR TERM DISCUSSION...
MAIN CONCERN IN THE NEAR TERM CONTINUES TO BE APPROACHING FRONTAL
WAVE AND ASSOCIATED PRECIP LATER THIS MORNING. LATEST REGIONAL
RADAR IMAGES SHOWING LEADING EDGE OF RAIN NOW EAST OF PIT AND
WORKING TOWARDS JST IN SW PA. AHEAD OF THIS PRECIP...A SUBSTANTIAL
AMOUNT OF DRY AIR REMAINS IN PLACE AS EVIDENCED BY 00Z PIT AND BUF
RAOBS. PRECIP IS BEING FORCED LARGELY BY ISENTROPIC ASCENT ALONG
THE 285-295 THETA SURFACES AS INCREASING WINDS AT THE 925 AND
850-MB LEVELS ASCEND THE APPROACHING FRONTAL BOUNDARY. WITH THE
AMOUNT OF DRY AIR IN PLACE...HAVE ELECTED TO TRIM BACK TIMING OF
PRECIP ARRIVAL TIME FROM THE TWIN TIERS AND POINTS SOUTH. IT NOW
APPEARS THAT PRECIP WILL NOT MAKE INTO THE CWA BEFORE 12Z AS
SUFFICIENT TIME WILL BE REQUIRED TO MOISTEN THE ATMOSPHERIC
COLUMN.
THE ABOVE SAID...MAIN ATTENTION CONTINUES TO FOCUS ON FZRA
POTENTIAL AS INITIAL BATCH OF PRECIP MOVES IN. CLOSE INSPECTION OF
BOTH RR AND WRF THETA SURFACES AND MODEL CONDENSATION PRESSURE
DEFICITS REVEALS APPROPRIATE SATURATION ALONG THE 285 SFC WILL NOT
OCCUR UNTIL 12-13Z AT THE EARLIEST. BY THIS TIME...DIURNAL TEMPS
SHOULD BEGIN REBOUNDING AS DAYTIME HEATING COMMENCES WHICH SHOULD
ONLY RESULT IN A VERY BRIEF PERIOD WHERE SFC TEMPS MAY BE COLD
ENOUGH TO SUPPORT FZRA ALONG THE ELEVATED SURFACES OF THE NORTHERN
TIER AND LOWER WYOMING VALLEY REGIONS OF NE PA.
BEYOND THIS...RA WILL GRADUALLY OVERSPREAD THE REGION THROUGH THE
MORNING AND AFTERNOON HRS. UP NORTH...PRECIP WILL LIKELY HOLD OFF
UNTIL EARLY AFTERNOON AFTER WHICH...WEAK SHORTWAVE ENERGY RIDING
ALONG THE FRONT SHOULD EVENTUALLY ALLOW PRECIP TO EXTEND AS FAR
NORTH AS THE SYR AND RME AREAS. RAINFALL AMOUNTS THROUGH THE DAY WILL
LIKELY REMAIN UNDER 2 TENTH OF AN INCH AT MOST LOCATIONS...WITH
EVEN LOWER AMOUNTS EXPECTED ACROSS THE NORTHERN FINGER LAKES AND
WESTERN MOHAWK VALLEY AS MAX FRONTAL FORCING REMAINS SOUTH. HIGH
TEMPS WILL TOP OUT IN LOWER 40S ACROSS THE NORTHERN FINGER LAKES
AND LAKE PLAIN...WITH MIDDLE TO UPPER 30S DOMINATE ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
FAIRLY ACTIVE PERIOD CONTINUING TO TAKE SHAPE THROUGH THE UPCOMING
WEEKEND AS THE NEXT IN A SERIES OF SFC LOWS LIFTS NORTH ALONG A
STALLED FRONT TO OUR WEST BEGINNING TONIGHT. THAT SAID...RA ACROSS
THE REGION SHOULD BECOME A LITTLE BIT MORE ORGANIZED INITIALLY
THIS EVENING AS SFC LOW LIFTS NORTH FROM THE LWR OHIO VLY INTO THE
LWR GREAT LAKES. AS THIS OCCURS...FORCING CONTRIBUTIONS FROM BOTH
THE POLAR AND SUBTROPICAL JETS WILL TRANSCEND ACROSS THE REGION
WITH ADDITIONAL FORCING ARRIVING FROM CONTINUED ISENTROPIC ASCENT
ALONG THE PREVIOUSLY MENTIONED WARM FRONT. THERMAL PROFILES FROM
ACROSS THE REGION INDICATE SFC TEMPS WILL REMAIN ABOVE FREEZING AS
WARM AIR ADVECTION CONTINUES. THIS SHOULD KEEP ANY PRECIP IN
LIQUID FORM.
SFC LOW PROGGED TO PASS TO OUR WEST ON SATURDAY WITH INCREASING
SOUTHWESTERLY FLOW FINALLY ALLOWING WARM FRONT TO LIFT NORTH
THROUGH THE ENTIRE CWA. AS A RESULT...EXPECT A WARMER DAY WITH
TEMPS TOPPING OUT IN THE UPPER 40S TO LOWER 50S ACROSS MUCH OF THE
AREA. WITH BEST FORCING FOR ASCENT ARRIVING FROM A NORTHERN STREAM
SHORTWAVE ACROSS THE UPPER GREAT LAKES...BEST CHANCES FOR
ORGANIZED PRECIP WILL LIKELY REMAIN NORTH AND WEST OF OUR AREA.
DESPITE THIS HOWEVER...SHORT TERM MODELS INDICATE A DEVELOPING SECONDARY
LOW OFF THE NJ COAST THROUGH THE DAY WHICH COMBINED WITH A WEAKER
SHORTWAVE IMPULSE PASSING OVERHEAD SHOULD KEEP THE CHC FOR SHWRS
ACROSS THE AREA THROUGH THE DAY. MAIN LOW EXPECTED TO PASS TO OUR
NORTH OVERNIGHT WHICH WILL SEND A COLD FRONT SOUTH ACROSS THE FCST
AREA. MODELS AGREE A QUICK COOL DOWN WILL OCCUR AFTER PASSAGE WITH
850-MB TEMPS QUICKLY FALLING TO -4C ACROSS THE FAR NORTH. HIGHLY
SHEARED FLOW COMBINED WITH THE INFLUX OF DRY AIR AND ONLY MARGINAL
TEMP DIFFERENCES WILL NEGATE ANY LAKE RESPONSE AND THUS HAVE DRIED
THINGS OUT FROM NORTH TO SOUTH OVERNIGHT EARLY SUN.
NEXT MORE POTENT WAVE TO LIFT NORTH FROM THE OHIO VLY ON SUN WHICH
WILL ONCE AGAIN LIFT THE FRONT BACK NORTH THROUGH BEGINNING SUN
NGT. AS SUCH...EXPECT INCREASING CHANCES FOR RAIN ONCE AGAIN SUN
AFTERNOON AND EVENING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
430 AM UPDATE...
NO CHGS NEEDED TO LONG TERM AT THIS TIME AS FRONT MVS THRU MON
EVNG WITH LKLY RAIN SHOWERS. NW FLOW KICKS IN FOLLOWING FROPA TO RESULT
IN LK EFFECT PCPN. BOTH 12Z AND NOW 00Z EC INDICATE DVLPNG SFC
LOPRES RIDING UP ALONG SFC BNDRY JUST OFF THE EAST COAST BY EARLY
WEEK, ALTHO NO OTHER MED RANGE MODELS HV THIS FEATURE.
PREV DISCUSSION BLO...
MEDIUM RANGE MODELS CONTINUE TO SHOW FAIR AGREEMENT THROUGH THE
EXTENDED PERIOD.
SUNDAY NIGHT THROUGH MONDAY, SFC LOW PRES WILL TRACK FROM THE OHIO
VALLEY NORTHEAST ACROSS LAKE ERIE INTO NEARBY SOUTHERN ONTARIO.
WILL CARRY LIKELY POPS BOTH PERIODS WITH RAIN LIKELY SUNDAY NIGHT
FOLLOWED BY RAIN SHOWERS ON MONDAY AS TRAILING COLD FRONT CROSSES
AREA MONDAY AFTERNOON AND EVENING. THROUGH MONDAY EVENING TEMPS
WILL REMAIN WARM ENOUGH FOR JUST LIQUID PRECIP TO FALL. MONDAY
NIGHT AS TEMPS LOWER UNDER CAA AND NORTHWEST FLOW, A WEAK LAKE
RESPONSE MAY OCCUR INTO TUESDAY.
TUESDAY NIGHT THROUGH THURSDAY, LOOKS DRY WITH SFC HIGH PRES
STRETCHING FROM THE MID ATLANTIC REGION INTO NEW ENGLAND.
TEMPS THROUGH THE PERIOD WILL START WELL ABOVE NORMAL THEN FALL TO
SEASONAL LEVELS TUESDAY AND WEDNESDAY BEFORE MODERATING AGAIN ON
THURSDAY.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
12Z UPDATE...
VFR INITIALLY WILL GIVE WAY TO MVFR CIGS LATE THIS MORNING. AS
PCPN MOVES FROM SOUTH TO NORTH IT WILL BRING MVFR VSBYS TO
TERMINALS AFTER 18Z. LIGHT RAIN WILL CONTINUE THROUGH THE DAY WITH
MVFR CONDITIONS EXPECTED. HIGHER TERMINALS WILL LIKELY SEE THESE
CIGS DECREASE TO IFR AFTER 05Z AS LOW LEVEL MOISTURE REMAINS
ENTRENCHED ACROSS THE AREA.
SOUTH WINDS AROUND 5 KTS WILL INCREASE TO NEAR 10KTS THIS
AFTERNOON THEN DIMINISH TO LGT/VRB AFTER 06Z.
OUTLOOK...
SATURDAY...MVFR IN SHRA.
SATURDAY NIGHT/SUNDAY MORNING...PRIMARILY VFR.
SUNDAY AFTERNOON THROUGH MONDAY EVENING...RESTRICTIONS EXPECTED IN
RAIN.
TUESDAY...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FREEZING RAIN ADVISORY UNTIL 11 AM EST THIS MORNING FOR PAZ040-
048-072.
FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ038-
039-043-044-047.
NY...FREEZING RAIN ADVISORY UNTIL 11 AM EST THIS MORNING FOR NYZ057-
062.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG
SHORT TERM...CMG
LONG TERM...PVN/RRM
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
639 AM EST FRI DEC 7 2012
.SYNOPSIS...
AN APPROACHING WARM FRONT WILL LEAD TO SCATTERED SHOWERS ACROSS
THE REGION TODAY. THIS WILL MARK THE BEGINNING OF A RATHER
UNSETTLED PERIOD WITH SCATTERED SHOWERS POSSIBLE EACH DAY AS
SEVERAL DISTURBANCES INTERACT WITH THE STALLED FRONT. TEMPERATURES
THROUGH THE WEEKEND WILL REMAIN ABOVE NORMAL AS ANY COLD AIR
REMAINS DISPLACED WELL TO OUR WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MAIN CONCERN IN THE NEAR TERM CONTINUES TO BE APPROACHING FRONTAL
WAVE AND ASSOCIATED PRECIP LATER THIS MORNING. LATEST REGIONAL
RADAR IMAGES SHOWING LEADING EDGE OF RAIN NOW EAST OF PIT AND
WORKING TOWARDS JST IN SW PA. AHEAD OF THIS PRECIP...A SUBSTANTIAL
AMOUNT OF DRY AIR REMAINS IN PLACE AS EVIDENCED BY 00Z PIT AND BUF
RAOBS. PRECIP IS BEING FORCED LARGELY BY ISENTROPIC ASCENT ALONG
THE 285-295 THETA SURFACES AS INCREASING WINDS AT THE 925 AND
850-MB LEVELS ASCEND THE APPROACHING FRONTAL BOUNDARY. WITH THE
AMOUNT OF DRY AIR IN PLACE...HAVE ELECTED TO TRIM BACK TIMING OF
PRECIP ARRIVAL TIME FROM THE TWIN TIERS AND POINTS SOUTH. IT NOW
APPEARS THAT PRECIP WILL NOT MAKE INTO THE CWA BEFORE 12Z AS
SUFFICIENT TIME WILL BE REQUIRED TO MOISTEN THE ATMOSPHERIC
COLUMN.
THE ABOVE SAID...MAIN ATTENTION CONTINUES TO FOCUS ON FZRA
POTENTIAL AS INITIAL BATCH OF PRECIP MOVES IN. CLOSE INSPECTION OF
BOTH RR AND WRF THETA SURFACES AND MODEL CONDENSATION PRESSURE
DEFICITS REVEALS APPROPRIATE SATURATION ALONG THE 285 SFC WILL NOT
OCCUR UNTIL 13Z AT THE EARLIEST. BY THIS TIME...DIURNAL TEMPS
SHOULD BEGIN REBOUNDING AS DAYTIME HEATING COMMENCES WHICH SHOULD
ONLY RESULT IN A VERY BRIEF PERIOD WHERE SFC TEMPS MAY BE COLD
ENOUGH TO SUPPORT FZRA ALONG THE ELEVATED SURFACES OF THE NORTHERN
TIER AND LOWER WYOMING VALLEY REGIONS OF NE PA. CONSIDERING THAT
ANY FZRA WILL BE VERY SHORTLIVED...ALONG WITH THE FACT THAT
OVERALL CONFIDENCE REMAINS BELOW 25%...HAVE ELECTED FOR FORGO ANY
WINTER WX HEADLINES FOR THE TIME BEING. IF TRENDS SUGGEST A BETTER
POTENTIAL FOR FREEZING PRECIP IN THE COMING HRS...A QUICK WSW
STATEMENT OR SPS CAN BE ISSUED AS NEEDED. HOWEVER WITH SUCH DRY
AIR IN PLACE AHEAD OF THE FRONT AND LATER ARRIVAL
TIME...CONFIDENCE IS JUST NOT HIGH ENOUGH TO WARRANT ANY HEADLINES
ATTM.
BEYOND THIS...RA WILL GRADUALLY OVERSPREAD THE REGION THROUGH THE
MORNING AND AFTERNOON HRS. UP NORTH...PRECIP WILL LIKELY HOLD OFF
UNTIL EARLY AFTERNOON AFTER WHICH...WEAK SHORTWAVE ENERGY RIDING
ALONG THE FRONT SHOULD EVENTUALLY ALLOW PRECIP TO EXTEND AS FAR
NORTH AS THE SYR AND RME AREAS. RAINFALL AMOUNTS THROUGH THE DAY WILL
LIKELY REMAIN UNDER 2 TENTH OF AN INCH AT MOST LOCATIONS...WITH
EVEN LOWER AMOUNTS EXPECTED ACROSS THE NORTHERN FINGER LAKES AND
WESTERN MOHAWK VALLEY AS MAX FRONTAL FORCING REMAINS SOUTH. HIGH
TEMPS WILL TOP OUT IN LOWER 40S ACROSS THE NORTHERN FINGER LAKES
AND LAKE PLAIN...WITH MIDDLE TO UPPER 30S DOMINATE ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
FAIRLY ACTIVE PERIOD CONTINUING TO TAKE SHAPE THROUGH THE UPCOMING
WEEKEND AS THE NEXT IN A SERIES OF SFC LOWS LIFTS NORTH ALONG A
STALLED FRONT TO OUR WEST BEGINNING TONIGHT. THAT SAID...RA ACROSS
THE REGION SHOULD BECOME A LITTLE BIT MORE ORGANIZED INITIALLY
THIS EVENING AS SFC LOW LIFTS NORTH FROM THE LWR OHIO VLY INTO THE
LWR GREAT LAKES. AS THIS OCCURS...FORCING CONTRIBUTIONS FROM BOTH
THE POLAR AND SUBTROPICAL JETS WILL TRANSCEND ACROSS THE REGION
WITH ADDITIONAL FORCING ARRIVING FROM CONTINUED ISENTROPIC ASCENT
ALONG THE PREVIOUSLY MENTIONED WARM FRONT. THERMAL PROFILES FROM
ACROSS THE REGION INDICATE SFC TEMPS WILL REMAIN ABOVE FREEZING AS
WARM AIR ADVECTION CONTINUES. THIS SHOULD KEEP ANY PRECIP IN
LIQUID FORM.
SFC LOW PROGGED TO PASS TO OUR WEST ON SATURDAY WITH INCREASING
SOUTHWESTERLY FLOW FINALLY ALLOWING WARM FRONT TO LIFT NORTH
THROUGH THE ENTIRE CWA. AS A RESULT...EXPECT A WARMER DAY WITH
TEMPS TOPPING OUT IN THE UPPER 40S TO LOWER 50S ACROSS MUCH OF THE
AREA. WITH BEST FORCING FOR ASCENT ARRIVING FROM A NORTHERN STREAM
SHORTWAVE ACROSS THE UPPER GREAT LAKES...BEST CHANCES FOR
ORGANIZED PRECIP WILL LIKELY REMAIN NORTH AND WEST OF OUR AREA.
DESPITE THIS HOWEVER...SHORT TERM MODELS INDICATE A DEVELOPING SECONDARY
LOW OFF THE NJ COAST THROUGH THE DAY WHICH COMBINED WITH A WEAKER
SHORTWAVE IMPULSE PASSING OVERHEAD SHOULD KEEP THE CHC FOR SHWRS
ACROSS THE AREA THROUGH THE DAY. MAIN LOW EXPECTED TO PASS TO OUR
NORTH OVERNIGHT WHICH WILL SEND A COLD FRONT SOUTH ACROSS THE FCST
AREA. MODELS AGREE A QUICK COOL DOWN WILL OCCUR AFTER PASSAGE WITH
850-MB TEMPS QUICKLY FALLING TO -4C ACROSS THE FAR NORTH. HIGHLY
SHEARED FLOW COMBINED WITH THE INFLUX OF DRY AIR AND ONLY MARGINAL
TEMP DIFFERENCES WILL NEGATE ANY LAKE RESPONSE AND THUS HAVE DRIED
THINGS OUT FROM NORTH TO SOUTH OVERNIGHT EARLY SUN.
NEXT MORE POTENT WAVE TO LIFT NORTH FROM THE OHIO VLY ON SUN WHICH
WILL ONCE AGAIN LIFT THE FRONT BACK NORTH THROUGH BEGINNING SUN
NGT. AS SUCH...EXPECT INCREASING CHANCES FOR RAIN ONCE AGAIN SUN
AFTERNOON AND EVENING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
430 AM UPDATE...
NO CHGS NEEDED TO LONG TERM AT THIS TIME AS FRONT MVS THRU MON
EVNG WITH LKLY RAIN SHOWERS. NW FLOW KICKS IN FOLLOWING FROPA TO RESULT
IN LK EFFECT PCPN. BOTH 12Z AND NOW 00Z EC INDICATE DVLPNG SFC
LOPRES RIDING UP ALONG SFC BNDRY JUST OFF THE EAST COAST BY EARLY
WEEK, ALTHO NO OTHER MED RANGE MODELS HV THIS FEATURE.
PREV DISCUSSION BLO...
MEDIUM RANGE MODELS CONTINUE TO SHOW FAIR AGREEMENT THROUGH THE
EXTENDED PERIOD.
SUNDAY NIGHT THROUGH MONDAY, SFC LOW PRES WILL TRACK FROM THE OHIO
VALLEY NORTHEAST ACROSS LAKE ERIE INTO NEARBY SOUTHERN ONTARIO.
WILL CARRY LIKELY POPS BOTH PERIODS WITH RAIN LIKELY SUNDAY NIGHT
FOLLOWED BY RAIN SHOWERS ON MONDAY AS TRAILING COLD FRONT CROSSES
AREA MONDAY AFTERNOON AND EVENING. THROUGH MONDAY EVENING TEMPS
WILL REMAIN WARM ENOUGH FOR JUST LIQUID PRECIP TO FALL. MONDAY
NIGHT AS TEMPS LOWER UNDER CAA AND NORTHWEST FLOW, A WEAK LAKE
RESPONSE MAY OCCUR INTO TUESDAY.
TUESDAY NIGHT THROUGH THURSDAY, LOOKS DRY WITH SFC HIGH PRES
STRETCHING FROM THE MID ATLANTIC REGION INTO NEW ENGLAND.
TEMPS THROUGH THE PERIOD WILL START WELL ABOVE NORMAL THEN FALL TO
SEASONAL LEVELS TUESDAY AND WEDNESDAY BEFORE MODERATING AGAIN ON
THURSDAY.
&&
.AVIATION /11Z FRIDAY THROUGH TUESDAY/...
12Z UPDATE...
VFR INITIALLY WILL GIVE WAY TO MVFR CIGS LATE THIS MORNING. AS
PCPN MOVES FROM SOUTH TO NORTH IT WILL BRING MVFR VSBYS TO
TERMINALS AFTER 18Z. LIGHT RAIN WILL CONTINUE THROUGH THE DAY WITH
MVFR CONDITIONS EXPECTED. HIGHER TERMINALS WILL LIKELY SEE THESE
CIGS DECREASE TO IFR AFTER 05Z AS LOW LEVEL MOISTURE REMAINS
ENTRENCHED ACROSS THE AREA.
SOUTH WINDS AROUND 5 KTS WILL INCREASE TO NEAR 10KTS THIS
AFTERNOON THEN DIMINISH TO LGT/VRB AFTER 06Z.
OUTLOOK...
SATURDAY...MVFR IN SHRA.
SATURDAY NIGHT/SUNDAY MORNING...PRIMARILY VFR.
SUNDAY AFTERNOON THROUGH MONDAY EVENING...RESTRICTIONS EXPECTED IN
RAIN.
TUESDAY...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG
SHORT TERM...CMG
LONG TERM...PVN/RRM
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
646 AM EST FRI DEC 7 2012
.SYNOPSIS...
A WARM FRONT WILL MOVE WESTWARD AND INTO COASTAL PORTIONS OF THE
CAROLINAS LATER TODAY. WEAK LOW PRESSURE WILL FORM ALONG THE FRONT
THIS EVENING...PUSHING THE BOUNDARY BACK OFFSHORE TONIGHT. WARM AND
DRY CONDITIONS ARE EXPECTED SATURDAY AFTERNOON INTO EARLY TUESDAY. A
COLD FRONT WILL MOVE THROUGH FROM THE WEST TUESDAY...ACCOMPANIED BY
BETTER RAIN CHANCES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...LATEST MODELS WERE NOT UNANIMOUS WITH THEIR
FORECAST FRONTAL POSITION FOR THIS AFTERNOON. 21Z FORECAST POSITIONS
RANGE FROM THE RUC (15 MILES WEST OF ILM TO 15 MILES EAST OF MYR) TO
THE GFS/NAM SOLUTION (GEORGETOWN TO CONWAY...WHITEVILLE AND
ELIZABETHTOWN.) WHILE OUR FORECAST HIGHS TODAY HAVE A MODERATE
DEGREE OF CONFIDENCE IN WILMINGTON (SHOULD BE ON THE WARM SIDE OF
THE BOUNDARY) AND IN FLORENCE (SHOULD BE ON THE COLD SIDE OF THE
BOUNDARY) THE AREA IN BETWEEN REMAINS LOW CONFIDENCE. PREVIOUS
DISCUSSION FROM 300 AM FOLLOWS...
IT IS A LOW-CONFIDENCE FORECAST TODAY OWING TO POOR MODEL
INITIALIZATION...LARGE MODEL SPREAD...AND TIGHT GRADIENTS IN SURFACE
TEMPERATURE EXPECTED ALONG A COASTAL FRONT. THE FRONT HAS JUST
PUSHED WEST ACROSS THE FRYING PAN SHOALS BUOY IN THE PAST HOUR WHERE
WINDS ARE NOW EASTERLY AND TEMPERATURES HAVE RISEN TO ALMOST 70
DEGREES.
RADAR COMPOSITES SHOW AN EXPANDING AREA OF LIGHT RAIN JUST SOUTH OF
CAPE FEAR PRODUCED BY LIFT ALONG THE 290-295K ISENTROPIC SURFACES.
AIR PARCELS ORIGINATING AT 925 MB EAST OF GEORGETOWN ARE BEING
FORCED TO ASCEND TO 850 MB BY THE TIME THEY MOVE NORTH OVER
LUMBERTON. THAT`S ABOUT 75 MB OF ASCENT IN 8 HOURS TIME AND SHOULD
RESULT IN SIGNIFICANT CLOUD COVER THROUGH THE DAY. PATCHES OF LIGHT
RAIN SHOULD ALSO DEVELOP AND SPREAD WEST TO THE I-95 CORRIDOR BY
EARLY AFTERNOON. RADAR ALSO REVEALS EMBEDDED HEAVIER SHOWERS WELL
OFFSHORE...ROOTED IN CONVECTIVE INSTABILITY ENHANCED BY THE WARM
WATER OF THE GULF STREAM. THESE HEAVIER SHOWERS SHOULD REMAIN OFF
THE COAST THROUGH TONIGHT.
HIGHS TODAY WILL BE HIGHLY DEPENDENT ON HOW MUCH INLAND PROGRESS THE
COASTAL FRONT MAKES BY LATE AFTERNOON. THE 00Z GFS AND NAM APPEAR TO
BE MOVING THE BOUNDARY TOO FAR INLAND...ERODING THE COLD AIR INLAND
TOO QUICKLY GIVEN THE AMOUNT OF CLOUD COVER ANTICIPATED TO LINGER
TODAY. THE BEST MODEL I CAN FIND IS THE 00Z NMM-EAST EXPERIMENTAL
RUN THAT SHOWS THE FRONT AT 7 PM THIS EVENING ABOUT 25 MILES INLAND
ACROSS SOUTHEASTERN NORTH CAROLINA...EXTENDING SOUTH ACROSS MYRTLE
BEACH AND GEORGETOWN. WITH THIS IN MIND...HIGHS SHOULD RANGE FROM
THE UPPER 60S IN WILMINGTON...TO THE UPPER 50S WEST OF I-95 WHERE
LOW CLOUDS AND THE COOL WEDGE AIRMASS SHOULD HOLD FIRM. THE BEACHES
WILL RUN AT LEAST 5 DEGREES COOLER THAN POINTS JUST A FEW MILES
INLAND DUE TO WINDS BLOWING IN FROM THE COOL SHALLOW WATER NEAR THE
COAST.
WEAK LOW PRESSURE WILL DEVELOP OFF THE SOUTH CAROLINA COAST ALONG
THE FRONT THIS EVENING. AS THE LOW MOVES NORTH OF CAPE FEAR AFTER
MIDNIGHT THE FRONT WILL BE PUSHED BACK OUT TO SEA...WITH THE OLD
WEDGE AIRMASS ADVECTING BACK TO THE COAST AND OFFSHORE. ANY
REMAINING RAIN NEAR THE COAST SHOULD ALSO END AS THE LOW PULLS THE
FRONT THROUGH. LOWS SHOULD FALL INTO THE UPPER 40S INLAND TO LOWER
50S NEAR THE COAST.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 2:45 AM FRIDAY...A WEST TO SLIGHTLY SOUTHWESTERLY FLOW WILL
PREVAIL THROUGH THE PERIOD AT THE MID LEVELS AS WEAK HIGH PRESSURE
WILL BE THE FEATURE OF NOTE AT THE SURFACE. THERE WILL BE INTERVALS
OF MID AND HIGH LEVEL CLOUDINESS FROM THE MOISTURE SLOWLY BUILDING
FROM THE WEST...OTHERWISE...LITTLE IN THE WAY OF SIGNIFICANT
WEATHER. SOUNDINGS DO SUPPORT A DECENT FOG EVENT FOR SUNDAY
MORNING...BUT THE AFOREMENTIONED CLOUDINESS MAY PROVE TO BE AN
IMPEDIMENT TO FORMATION. TEMPERATURE GUIDANCE IS STILL SUPPORTING
WIDESPREAD 70S SUNDAY. SATURDAY THE 70S WILL MOST LIKELY BE CONFINED
TO SOUTHWESTERN AREAS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 2:45 AM FRIDAY...EXTENDED FORECAST CONTINUES TO CENTER AROUND
THE COLD FRONT MOVING ACROSS THE AREA LATE MONDAY. MEDIUM RANGE
GUIDANCE SHOWS THE GFS THE MORE PROGRESSIVE SOLUTION AND THE ECMWF
SOMEWHAT SLOWER. THE 0000 UTC CYCLE OF THE OPERATIONAL GFS ALSO
INTRODUCES A SECONDARY WAVE ALONG THE SOUTHERN END OF THE FRONT
WHICH COULD EXTEND POPS INTO TUESDAY. IT IS CERTAINLY PLAUSIBLE AS
THE UNCERTAINTY IN THIS FORECAST FOR DAYS NOW HAS BEEN THE TIMING
OF SPEED MAX FEATURES ROUNDING THE PACIFIC RIDGE AND DIVING INTO
THE MEAN TROUGH. OTHERWISE THE EXTENDED REMAINS ESSENTIALLY
UNCHANGED WITH THE MORNING UPDATE. CHANCE POPS MONDAY FOLLOWED BY
A RETURN TO SEASONAL TEMPERATURES.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 12Z...IFR/NEAR IFR CEILINGS AT THE MYRTLES...WITH MAINLY MVFR
AT THE OTHER SITES. LOOK FOR A DIURNAL RISE TO MVFR AT THE MYRTLES
IN A COUPLE OF HOURS. COASTAL TROUGH CURRENTLY KICKING UP CONVECTION
MAINLY OVER THE GULF AT THIS TIME. NSSL WRF SHOWS CONVECTION
SKIRTING THE COAST THIS AFTERNOON AS THE TROUGH DRIFTS WESTWARD.
WILL INTRODUCE A TEMPO GROUP THIS AFTERNOON FOR SHOWERS.
TONIGHT...MODELS INDICATING ANOTHER ROUND OF IFR STRATUS AFTER
MIDNIGHT.
EXTENDED OUTLOOK...MORNING FOG/STRATUS POSSIBLE SATURDAY THROUGH
MONDAY. SHOWERS POSSIBLE TUESDAY ASSOCIATED WITH A COLD FRONT.
OTHERWISE VFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...NO SIGNIFICANT CHANGES HAVE BEEN MADE TO THE
FORECAST. SEAS AT THE FRYING PAN SHOALS BUOY REMAIN AROUND 6 FT...SO
THE ADVISORY WILL RUN FOR ANOTHER COUPLE OF HOURS. PREVIOUS
DISCUSSION FROM 300 AM FOLLOWS...
STRONG NORTHEAST WINDS OVER THE PAST 24 HOURS ARE FINALLY TAPERING
OFF AS HIGH PRESSURE OVER COASTAL NEW ENGLAND LOSES ITS GRIP ON THE
CAROLINAS. A COASTAL TROUGH LOCATED 35-45 MILES OFFSHORE WILL MOVE
WESTWARD TODAY...REACHING THE NC BEACHES BY EARLY AFTERNOON...AND
THE SC BEACHES BY EARLY THIS EVENING. WINDS SHOULD DIE DOWN
SUBSTANTIALLY FROM THE CURRENT 15-20 KNOT SPEEDS AS THE PRESSURE
GRADIENT IS MUCH MORE SLACK AROUND THE FRONT. WEAK LOW PRESSURE WILL
DEVELOP THIS EVENING ALONG THE FRONT OFF THE SOUTH CAROLINA
COAST...MOVING NORTHEAST OF CAPE FEAR AFTER MIDNIGHT. THIS WILL PULL
THE COASTAL FRONT OFFSHORE...WITH WEST TO NORTHWEST WINDS DEVELOPING
THROUGH DAYBREAK SATURDAY.
THE SMALL CRAFT ADVISORY HAS BEEN EXTENDED THROUGH 9 AM THIS MORNING
FOR ALL BUT THE HORRY COUNTY SC COASTAL WATERS TO ACCOUNT FOR
RESIDUAL 6-FOOT SEAS STILL INFERRED FROM AREA BUOY OBSERVATIONS. IN
ADDITION TO LOCAL SHORT PERIOD WIND WAVES...A 1-2 FOOT 10-SECOND
EASTERLY SWELL WILL CONTINUE TO PUSH TOWARD THE COAST THROUGH
TONIGHT.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 2:45 AM FRIDAY...RATHER UNEVENTFUL CONDITIONS FOR MARINERS
FOR THE WEEKEND AS A MODEST WESTERLY FLOW DEVELOPS
SATURDAY...AROUND TEN KNOTS AT BEST...FOLLOWED BY VERY WEAK WINDS
SUNDAY MORNING. SUNDAY WILL SEE MORE OF A SOUTHEAST FLOW TAKE
SHAPE ALBEIT SLOWLY AS THE NEXT SIGNIFICANT SYSTEM ORGANIZES WELL
TO THE WEST. SEAS OF 2-3 FEET CAN BE EXPECTED.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 2:45 AM FRIDAY...MAIN FEATURE FOR THE MARINE COMMUNITY WILL BE
THE COLD FRONT MOVING ACROSS THE WATERS LATE MONDAY. SOUTHWEST WINDS
OF 15-20 KNOTS WILL PRECEDE THE FRONT AND PROBABLY TOWARD THE HIGHER
END OF THE RANGE. SOME MEDIUM RANGE GUIDANCE HAS BEEN TRENDING
SLOWER SO THERE IS A POSSIBILITY OF A MORE PROLONGED PERIOD OF THIS
SOUTHWEST FLOW. FOR TUESDAY...A SOMEWHAT MUTED NORTHWESTERLY FLOW OF
10-15 KNOTS. SEAS WILL BE HIGHEST MONDAY WITH 4-7 FEET AND THE NEED
FOR A SMALL CRAFT ADVISORY. THE OFFSHORE FLOW TUESDAY WILL DIMINISH
SEAS TO A RANGE OF 2-4 FEET.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EST THIS MORNING FOR AMZ250-
252-256.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...43
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
352 PM MST FRI DEC 7 2012
.SHORT TERM...SNOW STILL ONGOING ACROSS MOUNTAINS...WITH SOME
ENHANCEMENT SHOWING UP ON RADAR ALONG THE CONTINENTAL DIVIDE.
LATEST WATER VAPOR INDICATE SOME SORT OF WAVE MOVING ACROSS
WYOMING WHICH MAY BE HELPING WITH THE SNOWFALL. ACROSS
PLAINS...SURGE MOVED ACROSS AREA WITH NORTHEAST WINDS UP TO THE
FOOTHILLS. LATEST RUC CROSS SECTIONS CONTINUE TO SHOW GOOD
MOISTURE ACROSS THE MOUNTAINS THROUGH TONIGHT AND OROGRAPHICS
SHOULD HELP TO KEEP SOME SNOW GOING THOUGH THERE APPEARS FROM
UPSTREAM OBSERVATIONS AND SATELLITE OF A BREAK IN THE MOISTURE. SO
THERE MAY BE SOME DECREASE IN THE SNOW AND WILL MAINTAIN THE
CHANCE POPS. WINDS TO INCREASE TONIGHT AHEAD OF AN APPROACHING
SYSTEM. LATEST MODELS CONTINUE TO SHOW THE DEVELOPMENT OF A DECENT
MOUNTAIN WAVE AND MOUNTAIN TOP INVERSION AFTER MIDNIGHT...WITH RUC
CROSS SECTIONS INDICATING 40 KTS OF CROSS MOUNTAIN FLOW BY 08Z.
LATEST NAM CROSS SECTIONS INDICATING EVEN STRONGER CROSS MOUNTAIN
FLOW OVERNIGHT AND INTO MUCH OF SATURDAY...AROUND 45 KTS AT
MOUNTAIN TOP AT 09Z TO A WHOPPING 75 KTS FROM 15Z TO ROUGHLY 21Z.
THESE VALUES LOOK A BIT OVERDONE...BUT MODELS ARE STILL SIMILAR IN
SHOWING HIGH WIND POTENTIAL FOR THE MOUNTAINS AS WELL AS THE
FOOTHILLS...THOUGH THE SHEAR MAY NOT IDEAL AND INVERSION MAY BE
BREAKING UP AS PATTERN TRANSITIONS FROM A CHINOOK PATTERN
OVERNIGHT TO A BORA PATTERN BY SATURDAY AFTERNOON WHEN THE MID
LEVEL ASCENT INCREASES. BEST TIME FOR THE HIGH WINDS THREAT WILL
BE 09Z TO 21Z SATURDAY. WILL ISSUE A HIGH WIND WARNING FOR THE
MOUNTAINS AND FOOTHILLS FROM 06Z FRIDAY THROUGH 00Z SUNDAY...OR
BASICALLY ALL OF SATURDAY. SHOULD SEE GUSTS OF AT LEAST 75 MPH
DURING THIS TIME FRAME. SHOULD ALSO SEE SNOW INCREASE AROUND 18Z
SATURDAY ACROSS THE MOUNTAINS AS THE JET SAGS INTO THE STATE AND
LIFT INCREASES WITH UP TO 4 INCHES POSSIBLE BY THE EVENING. WINDS
WILL ALSO CREATE BLOWING SNOW...MAINLY DURING THE AFTERNOON.
ACROSS PLAINS...CLOUDS TO GRADUALLY INCREASE THIS EVENING AS WINDS
SHIFT TO A DRAINAGE PATTERN. WINDS MAY GET A BIT GUSTY NEAR THE
FOOTHILLS OVERNIGHT AS DOWNSLOPE WINDS DEVELOP. ON
SATURDAY...MODELS CONTINUE TO SNOW CANADIAN FRONT MOVING ACROSS
THE AREA DURING THE AFTERNOON...WITH NORTHEAST UPSLOPE WINDS
HOLDING OFF UNTIL THE EVENING. GFS SHOWS SOME PRECIP ALONG THE
NORTHEAST CORNER LATE IN THE AFTERNOON. FOR NOW WILL KEEP THINGS
DRY THROUGH THE AFTERNOON. COLDER AIR TO MOVING INTO THE AREA
AFTER 00Z.
.LONG TERM...A SWIFT RIVER OF MOIST PACIFIC AIR ROUNDING THE
SOUTH SIDE OF A BROAD UPPER LEVEL TROUGH IS FORECAST TO BECOME
POSITIONED OVER NORTHERN COLORADO SATURDAY NIGHT. MODELS SHOW A
110-130KT WEST- EAST ORIENTED JET AT THE CORE OF THIS FLOW OVER
THE COLORADO FRONT RANGE MTNS FOR MOST OF SATURDAY NIGHT. HOWEVER
THROUGH THE NIGHT MODELS SHOW THE UPPER TROUGH DIGGING SOUTHWARD
TOWARD THE FOUR CORNERS WITH THE MEAN FLOW ALOFT BECOMING
PROGRESSIVELY MORE NORTHERLY IN DIRECTION AND SPEEDS DECREASING
SUBSTANTIALLY SUNDAY MORNING WITH THE BACK SIDE OF TROUGH SHIFTING
EASTWARD. CROSS SECTIONS INDICATE CROSS BARRIER WINDS OVERNIGHT ON
THE ORDER OF 45- 55KTS AT MTN TIME LEVEL. THE STRONG WINDS WILL
LIKELY COMBINE WITH SNOWFALL AND LIGHT TO MODERATE ACCUMULATIONS
TO PRODUCE AREAS OF BLOWING SNOW IN THE HIGH
COUNTRY...PARTICULARLY ON THE HIGH MTN PASSES AND UP AROUND THE
EISENHOWER TUNNEL OVERNIGHT. MAY BECOME NECESSARY TO HOIST A
WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW FOR THE MTN AND
FTHLS ZONES SHOULD THE NEXT MODEL RUN INDICATE A SIMILAR SETUP. AT
LOWER ELEVATIONS EAST OF THE MTNS...CANADIAN COLD FRONT DROPS
SOUTH ACROSS THE NORTHEAST PLAINS OF COLORADO EARLY SATURDAY AS
PER LATEST MODEL GUIDANCE FOLLOWED BY 6-9 HOURS OF NORTH-
NORTHEAST SFC-700 MB FLOW. SNOW CHANCES AND AMOUNTS EAST OF THE
MTNS LOOKING LESS IMPRESSIVE WITH THE 12Z AND 18Z MODEL RUNS.
MODEL SNOW GRIDS CONFINE THE BULK OF SNOW ACCUMULATION RIGHT UP
AGAINST THE FRONT RANGE FOOTHILLS AND OVER THE PALMER DIVIDE.
MODELS BARELY SHOW ANY SNOW ACCUMULATION EAST OF I-25 OR NORTH OF
U.S. HIGHWAY 6 FOR THIS STORM SYSTEM. OVERALL MODELS HAVE BEEN ALL
OVER THE PLACE WITH SNOW TOTALS AND COVERAGE...BUT ONE MODEL...THE
NAM...HAS CONSISTENTLY SHOWED LITTLE IF ANY SNOW EAST OF THE MTNS.
FOR THIS FCST PACKAGE LARGELY RELIED ON THE SREF TO LOAD QPF AND
SNOW AMTS IN THE FORECAST GRIDS.
LOOKING AHEAD TO SUNDAY...SHOULD SEE SNOWFALL DIMINISHING FORM NORTH
TO SOUTH IN THE MTNS AND NEARBY PLAINS THROUGH THE DAY...WITH LITTLE
ADDITIONAL ACCUMULATION ANTICIPATED. MAIN CONCERN ON SUNDAY WILL BE
THE MUCH BELOW AVERAGE TEMPERATURES AND BITTER WIND CHILLS WITH
NORTHERLY WINDS OF 10-25 MPH. DO NOT EXPECTED TO SEE DAYTIME
TEMPERATURES CLIMBING ABOVE THE UPPER 20S ANYWHERE IN THE FORECAST
AREA. WITH CLEARING SKIES OVERNIGHT...GOOD BET WE/LL SEE THE COLDEST
TEMPERATURES DO THE WINTER SEASON THUS FAR...WITH MTN VALLEYS
MERCURY READINGS WELL BELOW ZERO BY MORNING.
FOR MONDAY...ANOTHER SYSTEM RACES OUT OF THE PACIFIC NORTHWEST AND
ACROSS COLORADO BRINGING ANOTHER SHOT OF SNOW AND WIND TO THE MTNS
AND HIGH VALLEYS. COULD SEE A BIT OF LIGHT SNOW DURING THE
AFTERNOON/EVENING ON THE NORTHEAST PLAINS WITH ANTICYCLONIC UPSLOPE
FLOW FOR A TIME. NEW ACCUMULATIONS SHOULD BE LIGHT AND CONFINED TO
AREAS ABOVE TIMBERLINE AND NORTHWEST FACING MTN SLOPES.
LATER IN THE WEEK...SHOULD SEE A GRADUAL RETURN TO WARMER AND DRIER
CONDITIONS.
&&
.AVIATION...EASTERLY WINDS TO GRADUALLY DECREASE AND SWITCH TO
DRAINAGE DURING THE EVENING. SPEEDS OF AROUND 10 KTS TO PREVAIL
THOUGH SOME GUSTS TO 25 KTS POSSIBLE AT BJC AS DOWNSLOPE FLOW
DEVELOPS. WINDS TO SHIFT TO THE NORTHWEST BY 18Z THEN NORTH AROUND
21Z AS FRONT MOVES ACROSS AREA. COULD SEE SOME GUSTS TO 25 KTS
WITH FRONTAL PASSAGE. VFR CONDITIONS TO PREVAIL WITH A GRADUAL
INCREASE IN MID AND HIGH LEVEL MOISTURE. CEILINGS OF AROUND 6000
FEET COULD DEVELOP AFTER 21Z WITH POTENTIAL FOR ILS IMPACTS.
PRECIPITATION SHOULD HOLD OFF UNTIL THE EVENING WHEN THE COLDER
AIR MOVES OVER THE AREA.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING FROM 11 PM THIS EVENING TO 5 PM MST SATURDAY
FOR COZ033>036.
&&
$$
SHORT TERM...D-L
LONG TERM....BAKER
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1237 PM MST FRI DEC 7 2012
.UPDATE...
&&
.SHORT TERM...NORTHEAST SURGE CURRENTLY PUSHING SOUTH AND WEST
ACROSS PLAINS...A BIT STRONGER THAN PREVIOUSLY THOUGHT...WITH SOME
GUSTS AROUND 22 KTS. UPDATED WIND GRIDS FOR THIS CHANGE. SHOULD
SEE SOME DECREASE IN SPEEDS AFTER 21Z...PER LATEST RUC. THE RUC
ALSO BEGINNING TO GENERATE SOME LIGHT QPF ACROSS PORTIONS OF THE PLAINS
THROUGH 02Z. FOR NOW WILL KEEP OUT OF GRIDS BUT WILL NEED TO
MONITOR.
.AVIATION...TAFS UPDATED FOR STRONGER NORTHEAST PUSH ACROSS AREA
AIRPORTS...WITH DECREASING SPEEDS BY 21Z AS WINDS SHIFT TO THE
SOUTHEAST. BEGINNING TO SEE SOME CEILINGS AROUND 7000 FEET AGL
DEVELOPING NORTH AND EAST OF DENVER. WILL NEED TO MONITOR IF LOWER
CEILINGS DEVELOP.
&&
.PREV DISCUSSION... /ISSUED 948 AM MST FRI DEC 7 2012/
UPDATE...
SHORT TERM...WAVE CURRENTLY ACROSS EASTERN PLAINS WITH MID LEVEL
SUBSIDENCE SPREADING ACROSS MOUNTAINS AND FOOTHILLS. WEB CAMS
SHOWING MOUNTAIN SNOW ON THE DECREASE WITH LOSS OF LIFT. STILL
GOOD OROGRAPHICS FOR SOME SNOW TO CONTINUE THROUGH THE AFTERNOON
MAINLY WEST FACING SLOPES. ANY ADDITIONAL ACCUMULATION TO BE
MINIMAL. WINDS GUSTY ACROSS RIDGES AND ALONG FOOTHILLS IN WAKE OF
THE WAVE...BEING ENHANCED BY THE SUBSIDENCE. MODELS SHOW SOME
DECREASE IN THE WINDS BELOW THE RIDGES BY THE AFTERNOON. OVERALL
CURRENT FORECASTS SEEM TO BE HANDLING THE TRENDS NICELY...THOUGH
WINDS MAY NEED A BIT OF TWEEKING. STRONGER WINDS STILL EXPECTED
AFTER MIDNIGHT AHEAD OF A STRONGER SYSTEM. STILL SOME QUESTION
WHETHER SPEEDS WILL REACH HIGH WIND CRITERIA LATE TONIGHT INTO
SATURDAY MORNING DUE TO RATHER UNFAVORABLE SHEAR PROFILE. FOR NOW
THE CURRENT GUSTS IN THE 40 TO 60 MPH IN THE FOOTHILLS SEEM
REASONABLE. WILL LOOK FURTHER INTO THIS FOR THE AFTERNOON
ISSUANCE.
AVIATION...CURRENT TAF TRENDS STILL LOOKING ON TRACK. MODELS
CONTINUE TO SHOW WINDS TRANSITIONING TO THE NORTH NORTHWEST BY
18Z...THEN EAST TO SOUTHEAST AROUND 00Z. RUC DOES HOLD ONTO THE
NORTHERLIES THROUGH 02Z. WILL CONTINUE THE ONGOING TAF TRENDS FOR
THE UPCOMING ISSUANCE.
PREV DISCUSSION... /ISSUED 455 AM MST FRI DEC 7 2012/
SHORT TERM...ANOTHER WEAK SHORTWAVE IS PASSING OVER THIS
MORNING...ENOUGH TO KEEP SOME MID LEVEL CLOUD AROUND IN ADDITION
TO THE UBIQUITOUS WAVE CLOUDS...AND A COUPLE BANDS OF SNOW SHOWERS
DRAGGING ACROSS THE NORTHERN MOUNTAINS THIS MORNING. WEBCAMS SHOW
SOME ACCUMULATION AT THE EISENHOWER TUNNEL OVER THE LAST 3
HOURS...BUT TOTALS SHOULD BE 2 INCHES OR LESS. SOME DECREASE IN
THE MOISTURE AS WEAK SUBSIDENCE BEHIND THE WAVE COMES IN THIS
AFTERNOON...BUT THERE WILL LIKELY STILL BE SOME CLOUDS ESPECIALLY
UPSTREAM OF THE MOUNTAINS. SURFACE PRESSURE FALL/RISE COUPLET WITH
TODAYS WAVE IS MAINLY PASSING NORTH OF US...BUT WILL STILL SERVE
TO GIVE US A NORTHERLY COMPONENT TO THE LOW LEVEL WINDS ON THE
PLAINS TODAY AND A LITTLE COOLING BOTH AT THE SURFACE AND ALOFT
ALONG THE NORTHERN BORDER. WILL HANG ON TO THE HIGHS WE HAVE
FORECAST...BUT IF THE CLOUD COVER REMAINS THICK WE WILL NEED TO
TRIM THEM BACK A BIT.
TONIGHT THE WINDS INCREASE AHEAD OF THE STRONGER WEEKEND SYSTEM.
GOOD PROFILE FOR A MOUNTAIN WAVE OVERNIGHT...THOUGH THE MID LEVEL
FLOW IS NOT TOO STRONG UNTIL MORNING...AND BY THEN THE INVERSION
IS BREAKING DOWN AS COLD ADVECTION DEVELOPS. SHEAR IS ALSO A BIT
STRONGER THAN OPTIMAL...BUT NOT TOO MUCH. SO WE WILL BE
TRANSITIONING FROM A CHINOOK LIKE WAVE SETUP OVERNIGHT TO MORE OF
A BORA/BRUTE FORCE DOWNSLOPE TYPE WAVE SATURDAY MORNING THAT
SHOULD BRING HIGHER SPEEDS INTO THE LOWER FOOTHILLS...WHILE THE
PROSPECT FOR MUCH AMPLIFICATION SHOULD BE LESSENING. HIGH WIND
THREAT IS PROBABLY GREATEST IN THIS TRANSITION TIME EARLY
SATURDAY...AT THIS POINT IT LOOKS LIKE THE HIGH WIND THREAT IS
GREATEST IN THE HIGHER ELEVATIONS OF THE FRONT RANGE...SO I WILL
BE INCREASING SPEEDS BUT WILL NOT GO WITH A WATCH AT THIS
TIME...THINKING GUSTS OF 40-60 MPH IN THE FOOTHILLS OVERNIGHT.
MOISTURE WILL ALSO BE INCREASING AGAIN WITH THICKENING CLOUDS AND
A BETTER CHANCE OF LIGHT SNOW AGAIN IN THE MOUNTAINS TOWARD
MORNING.
LONG TERM...MODELS SHOW A WESTERLY JET MAXIMUM TO SAG SOUTHWARD
INTO THE NORTHERN CWA THROUGH THE DAY SATURDAY AS A MEAN UPPER
TROUGH DEVELOPS OVER A GOOD PORTION OF NORTH AMERICA. THIS JET
MAX CONTINUES PUSHING SOUTHWARD SATURDAY NIGHT AND OUT OF THE CWA
BY 12Z SUNDAY MORNING. SPEEDS ARE IN THE 100-110 KNOT RANGE. ON
SUNDAY...THE UPPER TROUGH AXIS MOVES EASTWARD ACROSS THE CWA. BY
EARLY SUNDAY EVENING IT IS EAST OF COLORADO AND STRONG NORTH-
NORTHWESTERLY FLOW ALOFT IS AT HAND FOR THE CWA. THE QG VERTICAL
VELOCITY FIELDS HAVE A BATCH OF WEAK UPWARD MOTION PROGGED
SATURDAY MORNING...THEN ANOTHER SHOT FROM 06Z TO 18Z SUNDAY
MORNING. BY SUNDAY AFTERNOON AND EVENING...DOWNWARD MOTION IS
PROGGED. THE LOW LEVEL WINDS ARE PROGGED TO BE DOWNSLOPING MUCH OF
SATURDAY...SOUTHWESTERLY OR WESTERLY IN DIRECTION. THERE IS STILL
A LINGERING MOUNTAIN WAVE SET UP SATURDAY MORNING. THIS SHOULD
BRING PRETTY STRONG DOWNSLOPING FLOW TO THE HIGHER FOOTHILLS AND
MOUNTAINS. A COLD FRONT AND UPSLOPE IS EXPECTED TO MOVE INTO THE
CWA LATE SATURDAY. THE NAM SHOWS MORE OF A 330-340 DEGREE WIND
DIRECTION IN THE BOUNDARY LAYER. THE GFS AND ECMWF SHOW MORE TEXT
BOOK UPSLOPE...360 TO 030 DEGREES. THE NORTHERLY LOW LEVEL FLOW IS
PROGGED TO CONTINUE THROUGH SUNDAY...WITH DOWNSLOPING SUNDAY
NIGHT AFTER THE UPPER TROUGH AXIS PASSES. THE UPSLOPE FLOW IS
FAIRLY DEEP...UP TO AROUND 600 MB ON THE MODELS. FOR MOISTURE
.MODELS ARE SOMEWHAT DRIER OVERALL COMPARED TO YESTERDAY`S 00Z
RUNS. MOISTURE INCREASES THROUGH THE DAY ON SATURDAY IN THE
MOUNTAINS...GETTING PRETTY DEEP BY 00Z SATURDAY EARLY EVENING. THE
PLAINS JUST HAVE SOME MOISTURE AROUND IN THE MID LEVELS AT THAT
TIME. MOISTURE GETS FAIRLY DEEP OVER THE PLAINS SATURDAY NIGHT
INTO HALF OF SUNDAY ON THE GFS AND ECMWF...THE NAM IS STILL WAY
DRIER. THE MOUNTAINS HAVE DEEP MOISTURE SATURDAY INTO EARLY
SUNDAY TOO. BY SUNDAY AFTERNOON...MOISTURE DECREASES OVER ALL THE
CWA...THIS TREND CONTINUES SUNDAY NIGHT AS WELL. THE QPF FIELDS
SHOW THE BEST ACCUMULATIONS IN THE MOUNTAINS AND FOOTHILLS
SATURDAY THROUGH SUNDAY AFTERNOON...ALTHOUGH VALUES ARE NOT
SIGNIFICANT. THE NAM HAS LESS THAN THE GFS AND ECMWF. THERE IS NO
MEASURABLE PRECIPITATION ON THE QPF FIELDS SUNDAY NIGHT. FOR
POPS...WILL STAY THE COURSE...BUT WILL KEEP THE PLAINS DRY ALL DAY
SATURDAY...JUST A TAD IN THE FOOTHILLS BY LATER AFTERNOON. THE
ONLY "LIKELY"S WILL STILL BE IN THE MOUNTAINS FOR THIS UPDATE.
WILL END ALL POPS BY LATE SUNDAY AFTERNOON. NO HIGHLIGHTS NEEDED.
IT SHOULD SNOW. I AM JUST RELUCTANT TO GO ALL OUT WITH THE NAM
BEING TO OUT OF SINK AND EVEN THE LATEST GFS SHOWING LESS
MOISTURE. FOR TEMPERATURES...SATURDAY`S HIGHS WILL BE 1-3 C COOLER
THAN TODAY`S. SUNDAY`S HIGHS WILL BE 10-14 C COLDER THAN
SATURDAY`S. IF SUNDAY NIGHT DOES INDEED CLEAR OUT...LOWS IN THE
GFE GRIDS FOR THAT PERIOD MAY NEED TO BE LOWERED YET MORE. FOR THE
LATER DAYS...MONDAY THROUGH THURSDAY...MODELS KEEP WEST-
NORTHWESTERLY FLOW ALOFT OVER THE CWA MONDAY INTO TUESDAY. A WEAK
TROUGH IS PROGGED TO MOVE ACROSS COLORADO TUESDAY AFTERNOON.
DIFFERENT FROM YESTERDAY. THERE IS SOME UPPER RIDGING ON
WEDNESDAY. BY WEDNESDAY NIGHT AND THURSDAY...PRETTY STRONG WEST-
SOUTHWESTERLY FLOW ALOFT IS PROGGED FOR THE FORECAST AREA AS AN
UPPER TROUGH DEVELOPS IN THE GREAT BASIN. THE GFS HAS QUITE A BIT
OF MOUNTAIN MOISTURE IN PLACE BY MONDAY AFTERNOON...THE ECMWF NOT
UNTIL MONDAY NIGHT. THE MOISTURE IS MOSTLY GONE BY MID DAY
TUESDAY. THEN IS IT PRETTY DRY WELL INTO THURSDAY. TEMPERATURES
COULD GET TO OR A TAD ABOVE NORMALS ON WEDNESDAY ONLY. THURSDAY
COOLS BACK DOWN.
AVIATION...VFR CONDITIONS WITH LIGHT WINDS TODAY...THERE MAY BE
SOME VARIABILITY IN THE WINDS BUT THE GENERAL TREND WILL BE TO
ROTATE FROM WEST OR NORTHWEST THIS MORNING THROUGH NORTH OR
NORTHEAST THIS AFTERNOON AND BACK AROUND TO SOUTH THIS EVENING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
948 AM MST FRI DEC 7 2012
.UPDATE...
&&
.SHORT TERM...WAVE CURRENTLY ACROSS EASTERN PLAINS WITH MID LEVEL
SUBSIDENCE SPREADING ACROSS MOUNTAINS AND FOOTHILLS. WEB CAMS
SHOWING MOUNTAIN SNOW ON THE DECREASE WITH LOSS OF LIFT. STILL
GOOD OROGRAPHICS FOR SOME SNOW TO CONTINUE THROUGH THE AFTERNOON
MAINLY WEST FACING SLOPES. ANY ADDITIONAL ACCUMULATION TO BE
MINIMAL. WINDS GUSTY ACROSS RIDGES AND ALONG FOOTHILLS IN WAKE OF
THE WAVE...BEING ENHANCED BY THE SUBSIDENCE. MODELS SHOW SOME
DECREASE IN THE WINDS BELOW THE RIDGES BY THE AFTERNOON. OVERALL
CURRENT FORECASTS SEEM TO BE HANDLING THE TRENDS NICELY...THOUGH
WINDS MAY NEED A BIT OF TWEEKING. STRONGER WINDS STILL EXPECTED
AFTER MIDNIGHT AHEAD OF A STRONGER SYSTEM. STILL SOME QUESTION
WHETHER SPEEDS WILL REACH HIGH WIND CRITERIA LATE TONIGHT INTO
SATURDAY MORNING DUE TO RATHER UNFAVORABLE SHEAR PROFILE. FOR NOW
THE CURRENT GUSTS IN THE 40 TO 60 MPH IN THE FOOTHILLS SEEM
REASONABLE. WILL LOOK FURTHER INTO THIS FOR THE AFTERNOON
ISSUANCE.
.AVIATION...CURRENT TAF TRENDS STILL LOOKING ON TRACK. MODELS
CONTINUE TO SHOW WINDS TRANSITIONING TO THE NORTH NORTHWEST BY
18Z...THEN EAST TO SOUTHEAST AROUND 00Z. RUC DOES HOLD ONTO THE
NORTHERLIES THROUGH 02Z. WILL CONTINUE THE ONGOING TAF TRENDS FOR
THE UPCOMING ISSUANCE.
&&
.PREV DISCUSSION... /ISSUED 455 AM MST FRI DEC 7 2012/
SHORT TERM...ANOTHER WEAK SHORTWAVE IS PASSING OVER THIS
MORNING...ENOUGH TO KEEP SOME MID LEVEL CLOUD AROUND IN ADDITION
TO THE UBIQUITOUS WAVE CLOUDS...AND A COUPLE BANDS OF SNOW SHOWERS
DRAGGING ACROSS THE NORTHERN MOUNTAINS THIS MORNING. WEBCAMS SHOW
SOME ACCUMULATION AT THE EISENHOWER TUNNEL OVER THE LAST 3
HOURS...BUT TOTALS SHOULD BE 2 INCHES OR LESS. SOME DECREASE IN
THE MOISTURE AS WEAK SUBSIDENCE BEHIND THE WAVE COMES IN THIS
AFTERNOON...BUT THERE WILL LIKELY STILL BE SOME CLOUDS ESPECIALLY
UPSTREAM OF THE MOUNTAINS. SURFACE PRESSURE FALL/RISE COUPLET WITH
TODAYS WAVE IS MAINLY PASSING NORTH OF US...BUT WILL STILL SERVE
TO GIVE US A NORTHERLY COMPONENT TO THE LOW LEVEL WINDS ON THE
PLAINS TODAY AND A LITTLE COOLING BOTH AT THE SURFACE AND ALOFT
ALONG THE NORTHERN BORDER. WILL HANG ON TO THE HIGHS WE HAVE
FORECAST...BUT IF THE CLOUD COVER REMAINS THICK WE WILL NEED TO
TRIM THEM BACK A BIT.
TONIGHT THE WINDS INCREASE AHEAD OF THE STRONGER WEEKEND SYSTEM.
GOOD PROFILE FOR A MOUNTAIN WAVE OVERNIGHT...THOUGH THE MID LEVEL
FLOW IS NOT TOO STRONG UNTIL MORNING...AND BY THEN THE INVERSION
IS BREAKING DOWN AS COLD ADVECTION DEVELOPS. SHEAR IS ALSO A BIT
STRONGER THAN OPTIMAL...BUT NOT TOO MUCH. SO WE WILL BE
TRANSITIONING FROM A CHINOOK LIKE WAVE SETUP OVERNIGHT TO MORE OF
A BORA/BRUTE FORCE DOWNSLOPE TYPE WAVE SATURDAY MORNING THAT
SHOULD BRING HIGHER SPEEDS INTO THE LOWER FOOTHILLS...WHILE THE
PROSPECT FOR MUCH AMPLIFICATION SHOULD BE LESSENING. HIGH WIND
THREAT IS PROBABLY GREATEST IN THIS TRANSITION TIME EARLY
SATURDAY...AT THIS POINT IT LOOKS LIKE THE HIGH WIND THREAT IS
GREATEST IN THE HIGHER ELEVATIONS OF THE FRONT RANGE...SO I WILL
BE INCREASING SPEEDS BUT WILL NOT GO WITH A WATCH AT THIS
TIME...THINKING GUSTS OF 40-60 MPH IN THE FOOTHILLS OVERNIGHT.
MOISTURE WILL ALSO BE INCREASING AGAIN WITH THICKENING CLOUDS AND
A BETTER CHANCE OF LIGHT SNOW AGAIN IN THE MOUNTAINS TOWARD
MORNING.
LONG TERM...MODELS SHOW A WESTERLY JET MAXIMUM TO SAG SOUTHWARD
INTO THE NORTHERN CWA THROUGH THE DAY SATURDAY AS A MEAN UPPER
TROUGH DEVELOPS OVER A GOOD PORTION OF NORTH AMERICA. THIS JET
MAX CONTINUES PUSHING SOUTHWARD SATURDAY NIGHT AND OUT OF THE CWA
BY 12Z SUNDAY MORNING. SPEEDS ARE IN THE 100-110 KNOT RANGE. ON
SUNDAY...THE UPPER TROUGH AXIS MOVES EASTWARD ACROSS THE CWA. BY
EARLY SUNDAY EVENING IT IS EAST OF COLORADO AND STRONG NORTH-
NORTHWESTERLY FLOW ALOFT IS AT HAND FOR THE CWA. THE QG VERTICAL
VELOCITY FIELDS HAVE A BATCH OF WEAK UPWARD MOTION PROGGED
SATURDAY MORNING...THEN ANOTHER SHOT FROM 06Z TO 18Z SUNDAY
MORNING. BY SUNDAY AFTERNOON AND EVENING...DOWNWARD MOTION IS
PROGGED. THE LOW LEVEL WINDS ARE PROGGED TO BE DOWNSLOPING MUCH OF
SATURDAY...SOUTHWESTERLY OR WESTERLY IN DIRECTION. THERE IS STILL
A LINGERING MOUNTAIN WAVE SET UP SATURDAY MORNING. THIS SHOULD
BRING PRETTY STRONG DOWNSLOPING FLOW TO THE HIGHER FOOTHILLS AND
MOUNTAINS. A COLD FRONT AND UPSLOPE IS EXPECTED TO MOVE INTO THE
CWA LATE SATURDAY. THE NAM SHOWS MORE OF A 330-340 DEGREE WIND
DIRECTION IN THE BOUNDARY LAYER. THE GFS AND ECMWF SHOW MORE TEXT
BOOK UPSLOPE...360 TO 030 DEGREES. THE NORTHERLY LOW LEVEL FLOW IS
PROGGED TO CONTINUE THROUGH SUNDAY...WITH DOWNSLOPING SUNDAY
NIGHT AFTER THE UPPER TROUGH AXIS PASSES. THE UPSLOPE FLOW IS
FAIRLY DEEP...UP TO AROUND 600 MB ON THE MODELS. FOR MOISTURE
..MODELS ARE SOMEWHAT DRIER OVERALL COMPARED TO YESTERDAY`S 00Z
RUNS. MOISTURE INCREASES THROUGH THE DAY ON SATURDAY IN THE
MOUNTAINS...GETTING PRETTY DEEP BY 00Z SATURDAY EARLY EVENING. THE
PLAINS JUST HAVE SOME MOISTURE AROUND IN THE MID LEVELS AT THAT
TIME. MOISTURE GETS FAIRLY DEEP OVER THE PLAINS SATURDAY NIGHT
INTO HALF OF SUNDAY ON THE GFS AND ECMWF...THE NAM IS STILL WAY
DRIER. THE MOUNTAINS HAVE DEEP MOISTURE SATURDAY INTO EARLY
SUNDAY TOO. BY SUNDAY AFTERNOON...MOISTURE DECREASES OVER ALL THE
CWA...THIS TREND CONTINUES SUNDAY NIGHT AS WELL. THE QPF FIELDS
SHOW THE BEST ACCUMULATIONS IN THE MOUNTAINS AND FOOTHILLS
SATURDAY THROUGH SUNDAY AFTERNOON...ALTHOUGH VALUES ARE NOT
SIGNIFICANT. THE NAM HAS LESS THAN THE GFS AND ECMWF. THERE IS NO
MEASURABLE PRECIPITATION ON THE QPF FIELDS SUNDAY NIGHT. FOR
POPS...WILL STAY THE COURSE...BUT WILL KEEP THE PLAINS DRY ALL DAY
SATURDAY...JUST A TAD IN THE FOOTHILLS BY LATER AFTERNOON. THE
ONLY "LIKELY"S WILL STILL BE IN THE MOUNTAINS FOR THIS UPDATE.
WILL END ALL POPS BY LATE SUNDAY AFTERNOON. NO HIGHLIGHTS NEEDED.
IT SHOULD SNOW. I AM JUST RELUCTANT TO GO ALL OUT WITH THE NAM
BEING TO OUT OF SINK AND EVEN THE LATEST GFS SHOWING LESS
MOISTURE. FOR TEMPERATURES...SATURDAY`S HIGHS WILL BE 1-3 C COOLER
THAN TODAY`S. SUNDAY`S HIGHS WILL BE 10-14 C COLDER THAN
SATURDAY`S. IF SUNDAY NIGHT DOES INDEED CLEAR OUT...LOWS IN THE
GFE GRIDS FOR THAT PERIOD MAY NEED TO BE LOWERED YET MORE. FOR THE
LATER DAYS...MONDAY THROUGH THURSDAY...MODELS KEEP WEST-
NORTHWESTERLY FLOW ALOFT OVER THE CWA MONDAY INTO TUESDAY. A WEAK
TROUGH IS PROGGED TO MOVE ACROSS COLORADO TUESDAY AFTERNOON.
DIFFERENT FROM YESTERDAY. THERE IS SOME UPPER RIDGING ON
WEDNESDAY. BY WEDNESDAY NIGHT AND THURSDAY...PRETTY STRONG WEST-
SOUTHWESTERLY FLOW ALOFT IS PROGGED FOR THE FORECAST AREA AS AN
UPPER TROUGH DEVELOPS IN THE GREAT BASIN. THE GFS HAS QUITE A BIT
OF MOUNTAIN MOISTURE IN PLACE BY MONDAY AFTERNOON...THE ECMWF NOT
UNTIL MONDAY NIGHT. THE MOISTURE IS MOSTLY GONE BY MID DAY
TUESDAY. THEN IS IT PRETTY DRY WELL INTO THURSDAY. TEMPERATURES
COULD GET TO OR A TAD ABOVE NORMALS ON WEDNESDAY ONLY. THURSDAY
COOLS BACK DOWN.
AVIATION...VFR CONDITIONS WITH LIGHT WINDS TODAY...THERE MAY BE
SOME VARIABILITY IN THE WINDS BUT THE GENERAL TREND WILL BE TO
ROTATE FROM WEST OR NORTHWEST THIS MORNING THROUGH NORTH OR
NORTHEAST THIS AFTERNOON AND BACK AROUND TO SOUTH THIS EVENING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
317 PM EST Fri Dec 7 2012
.NEAR TERM [Tonight]...
Objective RUC analysis shows a subtle surface convergence zone
coincident with a ribbon of higher 0-1km mixing ratios stretching
from coastal MS/AL southeastward into the eastern Gulf of Mexico.
There have been some scattered showers in this area for the bulk of
the day, and they are expected to continue overnight and into
Saturday morning. For tonight, they should remain mostly in our
western marine zones. However over time the 0-1km flow will veer to
a more southerly direction, which should allow some of the showers
to begin affecting our far western land zones (SE AL and the western
FL Panhandle). This is expected to be after 12z Saturday, so the
overnight forecast was kept dry for now. The only other concern is
for some fog, but at this time the pattern doesn`t seem to favor any
large areas of dense fog. Therefore, generic fog wording was added
to the grids overnight. Lows will be mild for another consecutive
night - around 56 at TLH (compared with a normal low of 43).
&&
.SHORT TERM [Saturday Through Monday]...
The current, mainly zonal 500 mb pattern will become much more
amplified by Monday, with a trough approaching our forecast area
over the central CONUS. Until then, there is excellent agreement
among the different sets of MOS in a continuation of above-average
temperatures for our region, with highs in the mid to upper 70s inland
(around 70 at the beaches), and lows in the mid to upper 50s
inland (around 60 at the beaches). The only reason we won`t
forecast even warmer high temperatures is because of the potential
for fog and low clouds to linger into the early afternoon hours in
some areas.
We did make a slight change to our previous forecast for Saturday,
as it now appears there will be at least a 20-30% chance of
showers, especially in our western zones. The forcing for this is
subtle, but it will apparently come from a combination of a weak
500 mb short wave translating rapidly eastward, a surface ridge axis
termination zone, and just boundary layer moisture and
instability to support moist convection. The latest Convection
Allowing Models are quite bullish of this rain, though they have
been known to over-forecast rain somewhat in this type of
synoptic pattern. Still, the fact that we`ve already observed
scattered showers over our Gulf coastal waters today indicates
that, at least over the water, the thermodynamics could support
shallow moist convection. Otherwise, rain chances will hold off
until Monday, when an approaching cold front will help trigger
scattered showers. The PoP will range from 50% just northwest of
our forecast area, to 20% in Valdosta and Cross City.
&&
.LONG TERM [Monday Night through Friday]...
The extended period will begin with a broad, but amplifying, trough
encompassing the entire country. Embedded within the large scale
trough will be several shortwaves. More notably for the local area
will be the disturbance positioned over the Four Corners region
Sunday night. It will move across the Gulf Coast states through
Monday, before exiting the Mid-Atlantic coast on Tuesday morning. At
about the same time, another disturbance will also position itself
over the Four Corners region before taking a similar path across the
Gulf Coast states through the remainder of next week. At the
surface, the effect from all of this will be a weakening surface
ridge on Monday, being replaced with an approaching cold front
likely to pass through the local area some time Monday night through
Tuesday morning. There is much less confidence in the forecast for
the remainder of the week, related to the second disturbance
mentioned above. However, it will likely result in a gloomy mid to
late week next week, with a possibility of disturbed weather through
Friday. Overall, this pattern will be a welcomed change, bringing a
chance for rain several days in the extended period. Additionally,
the abnormal heat will come to an end in the wake of the first
system, likely bringing temps back down to seasonal levels.
&&
.AVIATION [through 18z Saturday]...
Stratus has eroded across most of the area as of 20z, except
around the DHN and ECP terminals. We expect a period of VFR late
this afternoon and in the early evening at most, if not all,
terminals. After that, the forecast becomes a bit tricky with
signals from the model guidance rather inconsistent. Given that,
we generally trended all of the terminals down into the MVFR range
later tonight.
&&
.MARINE...
Winds and seas have been a bit higher than expected so far today,
as the pressure gradient appears to have tighten locally near the
trough south of the FL Panhandle. All of the NWP guidance,
including the few high resolution models that initialized the
stronger winds the best, insist that winds will quickly subside
this evening, and remain quite low through this weekend.
&&
.FIRE WEATHER...
RH will remain above 35% through at least Tuesday, with increasing
rain chances on Monday and Tuesday, so the fire weather concerns are
minimal for the next four days.
&&
.HYDROLOGY...
River stages continued to be well below action stage, and this is
likely to continue through at least the weekend.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 56 77 54 78 57 / 0 10 10 10 10
Panama City 61 74 60 75 62 / 10 20 10 10 10
Dothan 57 76 56 76 60 / 10 30 10 10 10
Albany 53 78 55 78 58 / 10 20 10 10 10
Valdosta 54 77 56 78 57 / 0 20 10 10 10
Cross City 55 78 54 80 56 / 0 20 10 10 10
Apalachicola 61 71 60 72 61 / 10 10 10 10 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM/AVIATION/FIRE WX...Lamers
SHORT TERM/HYDROLOGY...Fournier
LONG TERM...Harrigan
AREA FORECAST DISCUSSION
NWS GOODLAND KS
309 PM MST FRI DEC 7 2012
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 144 PM MST FRI DEC 7 2012
LATEST SATELLITE IMAGERY DEPICTS AN UPPER LEVEL TROUGH AXIS
EXTENDING FROM SOUTHEASTERN COLORADO NORTHEAST INTO NORTHERN MINNESOTA.
BEHIND THE TROUGH AXIS RUC ANALYSIS PLACES A SHORT WAVE TROUGH OVER
THE NE/SD LINE. AT THE SURFACE A PRE-FRONTAL TROUGH WAS MOVING
SOUTHEAST THROUGH THE PLAINS. SUBSIDENCE BEHIND THE SHORT WAVE TROUGH
AND TROUGH AXIS HAS LEAD TO CLEARING SKIES BEHIND THE SURFACE
FEATURE.
LATE THIS EVENING A WEAK SHORT WAVE TROUGH WILL DEVELOP OVER EASTERN
COLORADO AND PROGRESS ACROSS THE WESTERN HALF OF THE TRI-STATE
AREA. SREF/NAM ISENTROPIC ANALYSIS INDICATES LIFT AHEAD OF THE
SHORT WAVE TROUGH AROUND 700MB WHERE POINT SOUNDINGS ALSO SATURATE.
THE DRAWBACK IS A DRY LAYER BELOW THIS WHICH WILL LIMIT HOW MUCH
SNOW WILL REACH THE GROUND. THE MCCOOK AND NORTON AREA HAD A
SIMILAR SETUP THIS MORNING...WITH THE MCCOOK AIRPORT REPORTING
DRIZZLE. WITH THIS IN MIND WILL PLACE A MENTION OF FLURRIES AHEAD
OF THE SHORT WAVE TROUGH. THE FLURRIES WILL GENERALLY MOVE FROM
SOUTHWEST TO NORTHEAST DURING THE NIGHT OVER THE WESTERN HALF OF THE
AREA.
SATURDAY THE SHORT WAVE TROUGH WILL CONTINUE TO MOVE ACROSS THE AREA
DURING THE MORNING. HAVE THE FLURRIES CHANGING TO DRIZZLE
DURING THE LATE MORNING AS SURFACE TEMPERATURES WARM INTO THE LOWER
30S. THE ISENTROPIC LIFT AHEAD OF THE TROUGH WILL EXIT THE AREA BY
EARLY AFTERNOON. SOUTH WINDS WILL BE BREEZY DURING THE AFTERNOON AS
25KT 850MB WINDS MIX TO THE GROUND AND THE SURFACE PRESSURE GRADIENT
TIGHTENS. THE BREEZY WINDS WILL HELP WARM TEMPERATURES AHEAD OF THE
NEXT COLD FRONT...WHICH WILL MOVE INTO THE AREA DURING THE MID TO
LATE AFTERNOON. LIFTING AND MOISTURE WILL BE BEST ALONG AND SHORTLY
BEHIND THE FRONT. HOWEVER MODELS SHOW A FAIRLY DEEP DRY LAYER AS
THE FRONT MOVES THROUGH...WHICH MAY LIMIT THE AMOUNT OF RAIN THAT
REACHES THE GROUND. MODELS SHOW RAPID PRESSURE RISE BEHIND THE COLD
FRONT...WHICH WILL CAUSE WINDS TO STRENGTHEN BEHIND THE FRONT.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 247 PM MST
FRI DEC 7 2012
THE COLD FRONT WILL CONTINUE TO PUSH ACROSS THE FORECAST AREA
SATURDAY NIGHT. THE FAVORED AREA OF PRECIPITATION WILL INITIALLY BE
ACROSS THE NORTHERN SECTIONS OF THE FORECAST AREA IN THE VICINITY
OF THE FRONT WITH LIGHT RAIN CHANGING QUICKLY OVER TO LIGHT SNOW
AROUND SUNSET. A SLIGHT CHANCE OF LIGHT SNOW WILL SPREAD ACROSS THE
FORECAST AREA WITH THE FRONT...WITH THE BEST CHANCE OF
PRECIPITATION REMAINING ALONG THE NORTHERN TIER OF COUNTIES WHERE
THE SYNOPTIC SCALE LIFT REMAINS GREATER AS A SERIES OF SHORT WAVES
SHEAR OUT ACROSS THE PLAINS AHEAD OF THE MAIN UPPER TROUGH. THE
POSSIBILITY OF PRECIPITATION DECREASES THROUGH THE REMAINDER OF
SATURDAY NIGHT AND SUNDAY MORNING...WITH LIGHT SNOW ENDING BY MID
DAY ON SUNDAY. WITH THE STEEP PRESSURE GRADIENT REMAINING OVER THE
CENTRAL HIGH PLAINS REGION...EXPECT NORTH WINDS OF 20-30 MPH WILL
BE COMMON DURING THE DAY ON SUNDAY.
THE PRIMARY DEEP UPPER TROUGH SWEEPS QUICKLY THROUGH THE REGION
SUNDAY NIGHT WITH A COLD AREA OF HIGH PRESSURE MOVING IN BEHIND
THE FRONT. OVERNIGHT LOW TEMPERATURES WILL DROP INTO THE SINGLE
DIGITS AS SKIES ALSO BEGIN TO CLEAR OUT AND WINDS SLACKEN SUNDAY
NIGHT.
A SERIES OF OPEN WAVES WILL MOVE THROUGH THE UPPER FLOW NEXT
WEEK. ALTHOUGH THE PATTERN REMAINS ACTIVE...NO ADDITIONAL
PRECIPITATION IS EXPECTED THROUGH NEXT WEEK. COLDER TEMPERATURES
WILL CONTINUE INTO THE BEGINNING OF NEXT WEEK WITH A GRADUAL
WARMING BRINGING TEMPERATURES BACK TO NEAR AVERAGE FOR THIS TIME
OF YEAR THROUGH THE MIDDLE AND END OF NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1042 AM MST FRI DEC 7 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD AT BOTH GLD AND
MCK. A LEE SURFACE TROUGH WILL SOON PUSH THROUGH BOTH
TERMINALS...TURNING WINDS FROM THE SOUTHWEST TO NORTH-NORTHWEST.
SKIES WILL BE CLEAR TODAY BEHIND THE TROUGH BEFORE MID LEVEL CLOUDS
INCREASE LATE TONIGHT DUE TO A WEAK MID-LEVEL DISTURBANCE. WINDS
WILL TURN BACK TO THE SOUTH-SOUTHWEST BY TOMORROW MORNING BEHIND
THIS DISTURBANCE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JTL
LONG TERM...LOCKHART
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
156 PM MST FRI DEC 7 2012
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 144 PM MST FRI DEC 7 2012
LATEST SATELLITE IMAGERY DEPICTS AN UPPER LEVEL TROUGH AXIS
EXTENDING FROM SOUTHEASTERN COLORADO NORTHEAST INTO NORTHERN MINNESOTA.
BEHIND THE TROUGH AXIS RUC ANALYSIS PLACES A SHORT WAVE TROUGH OVER
THE NE/SD LINE. AT THE SURFACE A PRE-FRONTAL TROUGH WAS MOVING
SOUTHEAST THROUGH THE PLAINS. SUBSIDENCE BEHIND THE SHORT WAVE TROUGH
AND TROUGH AXIS HAS LEAD TO CLEARING SKIES BEHIND THE SURFACE
FEATURE.
LATE THIS EVENING A WEAK SHORT WAVE TROUGH WILL DEVELOP OVER EASTERN
COLORADO AND PROGRESS ACROSS THE WESTERN HALF OF THE TRI-STATE
AREA. SREF/NAM ISENTROPIC ANALYSIS INDICATES LIFT AHEAD OF THE
SHORT WAVE TROUGH AROUND 700MB WHERE POINT SOUNDINGS ALSO SATURATE.
THE DRAWBACK IS A DRY LAYER BELOW THIS WHICH WILL LIMIT HOW MUCH
SNOW WILL REACH THE GROUND. THE MCCOOK AND NORTON AREA HAD A
SIMILAR SETUP THIS MORNING...WITH THE MCCOOK AIRPORT REPORTING
DRIZZLE. WITH THIS IN MIND WILL PLACE A MENTION OF FLURRIES AHEAD
OF THE SHORT WAVE TROUGH. THE FLURRIES WILL GENERALLY MOVE FROM
SOUTHWEST TO NORTHEAST DURING THE NIGHT OVER THE WESTERN HALF OF THE
AREA.
SATURDAY THE SHORT WAVE TROUGH WILL CONTINUE TO MOVE ACROSS THE AREA
DURING THE MORNING. HAVE THE FLURRIES CHANGING TO DRIZZLE
DURING THE LATE MORNING AS SURFACE TEMPERATURES WARM INTO THE LOWER
30S. THE ISENTROPIC LIFT AHEAD OF THE TROUGH WILL EXIT THE AREA BY
EARLY AFTERNOON. SOUTH WINDS WILL BE BREEZY DURING THE AFTERNOON AS
25KT 850MB WINDS MIX TO THE GROUND AND THE SURFACE PRESSURE GRADIENT
TIGHTENS. THE BREEZY WINDS WILL HELP WARM TEMPERATURES AHEAD OF THE
NEXT COLD FRONT...WHICH WILL MOVE INTO THE AREA DURING THE MID TO
LATE AFTERNOON. LIFTING AND MOISTURE WILL BE BEST ALONG AND SHORTLY
BEHIND THE FRONT. HOWEVER MODELS SHOW A FAIRLY DEEP DRY LAYER AS
THE FRONT MOVES THROUGH...WHICH MAY LIMIT THE AMOUNT OF RAIN THAT
REACHES THE GROUND. MODELS SHOW RAPID PRESSURE RISE BEHIND THE COLD
FRONT...WHICH WILL CAUSE WINDS TO STRENGTHEN BEHIND THE FRONT.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 231 AM MST FRI DEC 7 2012
TROUGH WILL REMAIN IN PLACE ACROSS THE HIGH/CENTRAL PLAINS THROUGH
TUESDAY WITH SHORTWAVE RIDGE BUILDING BACK INTO THE INTER-MOUNTAIN
WEST BY WEDNESDAY. RESULT WILL BE A GRADUAL WARM-UP WITH BELOW
NORMAL HIGH TEMPS IN THE 30S MONDAY AND UPPER 30S/LOW 40S TUESDAY.
THERE IS QUITE A BIT OF SPREAD BETWEEN ECMWF AND GFS REGARDING
SHORTWAVE RIDGE WED. FOR NOW ABOVE NORMAL TEMPS IN THE UPPER 40S ARE
FORECAST...HOWEVER SPREAD IN GUIDANCE COULD SUPPORT TEMPS 5F COOLER
OR WARMER THAN THIS. HIGH TEMPS SHOULD BE NEAR SEASONAL LEVELS
THU...THOUGH THERE IS INDICATION FROM PREVIOUS MODEL RUNS OF
POSSIBLE FROPA THAT COULD RESULT IN SLIGHTLY COOLER TEMPS THAN
CURRENTLY IN THERE. NOT ENOUGH CONFIDENCE TO GO LOWER THAN UPPER
30S/LOW 40S FOR HIGHS THU. SUBSIDENCE AND DRY AIR MASS SHOULD BE IN
PLACE THROUGH THURSDAY...SO I LEFT FORECAST DRY.
BY THE END OF NEXT WEEK ANOTHER TROUGH WILL BUILD OVER THE WESTERN
US TOWARDS THE INTER-MOUNTAIN WEST THAT COULD BRING ANOTHER ARCTIC
AIR MASS AND POSSIBLE SNOW CHANCES BY NEXT WEEKEND. THIS IS
PRIMARILY OUTSIDE THE VALID FORECAST PERIOD...SO WILL NOT AFFECT THE
ONGOING FORECAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1042 AM MST FRI DEC 7 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD AT BOTH GLD AND
MCK. A LEE SURFACE TROUGH WILL SOON PUSH THROUGH BOTH
TERMINALS...TURNING WINDS FROM THE SOUTHWEST TO NORTH-NORTHWEST.
SKIES WILL BE CLEAR TODAY BEHIND THE TROUGH BEFORE MID LEVEL CLOUDS
INCREASE LATE TONIGHT DUE TO A WEAK MID-LEVEL DISTURBANCE. WINDS
WILL TURN BACK TO THE SOUTH-SOUTHWEST BY TOMORROW MORNING BEHIND
THIS DISTURBANCE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JTL
LONG TERM...DR
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1042 AM MST FRI DEC 7 2012
.UPDATE...
ISSUED AT 748 AM MST FRI DEC 7 2012
RADAR IMAGERY OVER THE LAST HOUR HAS SHOWN SOME WEAK ECHOES OVER
THE MCCOOK AND NORTON AREAS. SURFACE TEMPERATURES HAVE BEEN AROUND
30 DEGREES AND THE RUC SOUNDING FROM MCCOOK INDICATED NO ICE BEING
INTRODUCED INTO THE MID/LOW LEVEL CLOUDS. CALLED THE MCCOOK
DISPATCH WHO REPORTED DRIZZLE...WITH NO ICE ACCUMULATING EVEN ON
ELEVATED SURFACES. WITH THIS IN MIND...AND TEMPERATURES CONTINUING
TO WARM...DECIDED TO CALL THIS DRIZZLE FOR THE FORECAST.
ISENTROPIC ANALYSIS INDICATES THE LIFT FOR THIS AREA WILL LAST
THROUGH THE MORNING THEN MOVE EAST OUT OF THE AREA DURING THE
EARLY AFTERNOON AHEAD OF THE WEAK COLD FRONT. ALSO MENTION
SLIGHTLY REDUCED VISIBILITIES IN THE DRIZZLE DUE TO MCCOOK
REPORTING 4 MILES BRIEFLY THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 231 AM MST FRI DEC 7 2012
AS OF 2 AM...SKIES ACROSS THE TRI-STATE AREA WERE PARTLY CLOUDY TO
MOSTLY CLOUDY. TEMPERATURES WERE IN THE MID 20S TO MID 30S ACROSS
THE REGION. WINDS WERE GENERALLY LIGHT BUT SOUTH WINDS HAVE STARTED
TO PICK UP A LITTLE OVER EASTERN COLORADO AHEAD OF A DEVELOPING
LEE TROUGH.
THE LEE TROUGH WILL MOVE ACROSS THE REGION THIS AFTERNOON...ALLOWING
SOUTH WINDS TO BECOME NORTHWEST WINDS AFTER THE TROUGH PASSAGE. SKY
FORECAST FOR TODAY IS SOMEWHAT TRICKY AND LARGELY DEPENDS ON THE
AMOUNT OF CIRRUS THAT DEVELOPS TO THE WEST. WENT WITH PARTLY CLOUDY
SKIES FOR MOST OF THE DAY. HIGH TEMPERATURES WILL BE IN THE LOW TO
MID 50S FOR TODAY. THIS WILL BE THE WARMEST DAY FOR AT LEAST THE
NEXT WEEK AS A FEW COLD FRONTS WILL MOVE THROUGH AND KEEP THINGS
QUITE COLD.
A LARGE LONGWAVE TROUGH WILL BEGIN PUSHING INTO THE AREA ON
SATURDAY. MODELS ARE BEGINNING TO AGREE ON A SOLUTION THAT IS NOT
TOO FAVORABLE FOR PRECIPITATION IN THE REGION. MODELS ARE
PROJECTING A SPLIT FLOW PATTERN WITH THE TRI-STATE AREA IN THE
MIDDLE. ALL MODELS ALSO SHOW THAT TWO SEPARATE LOW PRESSURE
SYSTEMS WILL DEVELOP AHEAD OF THIS UPPER LEVEL DISTURBANCE. THE
FIRST WILL DEVELOP OVER THE NORTHERN PLAINS. THIS LOW PRESSURE
WILL MOVE TOWARDS MINNESOTA AND KEEP MOST OF THE BEST FORCING AND
PRECIPITATION OVER NEBRASKA AND SOUTH DAKOTA. THE SECOND LOW
PRESSURE WILL DEVELOP TO THE SOUTH...OVER THE TEXAS PANHANDLE.
THIS SECOND SOLUTION WOULD FAVOR A BETTER CHANCE FOR PRECIPITATION
ACROSS KANSAS. MODELS DISAGREE ON HOW STRONG THE LOW PRESSURES
WILL BE. THE EUROPEAN IS THE ONLY MODEL THAT SHOWS THE SOUTHERN
LOW BECOMING THE DOMINANT LOW...WHICH WOULD BE MORE FAVORABLE FOR
PRECIPITATION HERE IN THE TRI-STATE AREA. UNFORTUNATELY...THE
PRECIPITATION FOR THE EUROPEAN MODEL LOOKS A LITTLE OVERDONE
CONSIDERING THE AMOUNT OF DRY AIR THAT WILL MOVE IN WITH THIS
FRONT. AS A RESULT...HAVE LEANED TOWARDS THE DRIER SOLUTIONS OF
THE NAM...CANADIAN AND GFS MODELS. THE MODELS DO HAVE SOME
VARIABLES THAT WOULD FAVOR HIGHER SNOWFALL AMOUNTS...HOWEVER THE
AMOUNT OF DRY AIR LOOKS LIKE TOO MUCH TO OVERCOME AT THE PRESENT
MOMENT. MODEL CONSISTENCY IS INCREASING WITH THE EUROPEAN
REMAINING AS THE ONLY OUTLIER.
THE COLD FRONT WILL PASS THROUGH LATE SATURDAY EVENING AND INTO
SATURDAY NIGHT. SOME SNOW SHOWERS ARE POSSIBLE ALONG THE
FRONT...HOWEVER DUE TO THE DRY AIR ACCUMULATIONS WILL LIKELY BE ONE
INCH OR LESS. TEMPERATURES WILL BE QUITE COLD BEHIND THE FRONT WITH
STRONG NORTH WINDS. HIGH TEMPERATURES ON SUNDAY WILL LIKELY NOT MAKE
IT INTO THE 30S. LOW TEMPERATURES ON SUNDAY NIGHT WILL FALL INTO THE
SINGLE DIGITS ACROSS MOST OF THE REGION...WITH WIND CHILL READINGS
AS LOW AS ZERO OR POSSIBLY BELOW ZERO. LOW TEMPERATURES COULD
FALL LOWER THAN FORECAST IF SKIES CLEAR QUICKER THAN EXPECTED AS A
DRY SLOT MOVES INTO THE BACK OF THE DEPARTING WEATHER SYSTEM.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 231 AM MST FRI DEC 7 2012
TROUGH WILL REMAIN IN PLACE ACROSS THE HIGH/CENTRAL PLAINS THROUGH
TUESDAY WITH SHORTWAVE RIDGE BUILDING BACK INTO THE INTER-MOUNTAIN
WEST BY WEDNESDAY. RESULT WILL BE A GRADUAL WARM-UP WITH BELOW
NORMAL HIGH TEMPS IN THE 30S MONDAY AND UPPER 30S/LOW 40S TUESDAY.
THERE IS QUITE A BIT OF SPREAD BETWEEN ECMWF AND GFS REGARDING
SHORTWAVE RIDGE WED. FOR NOW ABOVE NORMAL TEMPS IN THE UPPER 40S ARE
FORECAST...HOWEVER SPREAD IN GUIDANCE COULD SUPPORT TEMPS 5F COOLER
OR WARMER THAN THIS. HIGH TEMPS SHOULD BE NEAR SEASONAL LEVELS
THU...THOUGH THERE IS INDICATION FROM PREVIOUS MODEL RUNS OF
POSSIBLE FROPA THAT COULD RESULT IN SLIGHTLY COOLER TEMPS THAN
CURRENTLY IN THERE. NOT ENOUGH CONFIDENCE TO GO LOWER THAN UPPER
30S/LOW 40S FOR HIGHS THU. SUBSIDENCE AND DRY AIR MASS SHOULD BE IN
PLACE THROUGH THURSDAY...SO I LEFT FORECAST DRY.
BY THE END OF NEXT WEEK ANOTHER TROUGH WILL BUILD OVER THE WESTERN
US TOWARDS THE INTER-MOUNTAIN WEST THAT COULD BRING ANOTHER ARCTIC
AIR MASS AND POSSIBLE SNOW CHANCES BY NEXT WEEKEND. THIS IS
PRIMARILY OUTSIDE THE VALID FORECAST PERIOD...SO WILL NOT AFFECT THE
ONGOING FORECAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1042 AM MST FRI DEC 7 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD AT BOTH GLD AND
MCK. A LEE SURFACE TROUGH WILL SOON PUSH THROUGH BOTH
TERMINALS...TURNING WINDS FROM THE SOUTHWEST TO NORTH-NORTHWEST.
SKIES WILL BE CLEAR TODAY BEHIND THE TROUGH BEFORE MID LEVEL CLOUDS
INCREASE LATE TONIGHT DUE TO A WEAK MID-LEVEL DISTURBANCE. WINDS
WILL TURN BACK TO THE SOUTH-SOUTHWEST BY TOMORROW MORNING BEHIND
THIS DISTURBANCE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...RRH
LONG TERM...DR
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1143 AM CST FRI DEC 7 2012
.AVIATION...A CU FIELD IS CURRENTLY DEVELOPING ACROSS SE TX AND IS
SPREADING INTO LA. THIS TREND WILL CONTINUE THROUGH THE NEXT FEW
HRS AS HEATING OCCURS. MVFR CEILINGS WILL BE POSSIBLE INTO THE
LATE AFTERNOON TO EARLY EVENING. THE CU WILL BREAK UP AROUND
SUNSET, HOWEVER FOG WILL BEGIN TO DEVELOP BEFORE MIDNIGHT. HIGH
CLOUDS MAY INHIBIT SOME FOG, HOWEVER MOST TERMINALS WILL STILL BE
AFFECTED. IFR AND POTENTIALLY LIFR CONDITIONS WILL BE POSSIBLE
INTO SAT MORNING. WINDS WILL BE SE TO S AT 10KTS OR LESS.
&&
.PREV DISCUSSION... /ISSUED 936 AM CST FRI DEC 7 2012/
UPDATE...
FOG IS BEGINNING TO LIFT THIS MORNING AND WILL END THE DENSE FOG
ADVISORY. OTHERWISE SKIES WILL BE CLEARING ALLOWING TEMPERATURES
TO WARM INTO THE MID 70S TODAY. WE ARE IN THIS SAME PATTERN FOR
TOMORROW WITH CHANGES IN THE WEATHER TO BEGIN ON SUNDAY AS
ANOTHER COLD FRONT DROPS DOWN FROM THE PLAINS STATES.
PREV DISCUSSION... /ISSUED 608 AM CST FRI DEC 7 2012/
AVIATION...BLO MINS CONDITIONS EXCEPT BPT WHERE STRATCU CIGS
STAYED IN MOST OF THE NIGHT AND WINDS WERE A BIT STRONGER AND SWLY
AT GRADIENT LEVELS. OTHERWISE IMPROVEMENT ABV MINS SHORTLY AT AEX,
AND IN A COUPLE OF HOURS AT LCH AS SWLY BOUNDARY LEVEL FLOW
BEGINS TO LIFT THE FOG TOWARDS MVFR.
BY MID MORNING ACADIANA AIRPORTS ARA AND LFT SHOULD FOLLOW SUIT
AS TEMPS APPROACH BURNOFF OF 65F/18C. STILL LOOKING VFR FOR AEX AS
WELL AS LFT AND ARA THIS AFTERNOON. MVFR CIGS SHOULD HANG IN THE REST OF
THE DAY AT BPT AND LCH LOOKING AT LATEST RUC TRENDS. VLIFR
CONDITIONS SHOULD REPEAT STARTING LATE EVENING AS THE WEAK DECEMBER
SUN AND AN INVERSION HAS TRAPPED LOW LEVEL MOISTURE IN PLACE.
SWEENEY
PREV DISCUSSION... /ISSUED 412 AM CST FRI DEC 7 2012/
SYNOPSIS...
AN ATLANTIC DOME OF HIGH PRESSURE...LOCATED OFFSHORE THE
CAROLINA`S...RIDGES WESTWARD THROUGH SOUTHEAST LOUISIANA.
DISCUSSION...
DRY MEXICAN AIR IS RIDING IN ON A LOW LEVEL SOUTHWESTERLY AIRSTREAM.
THE OVERRIDING DRY AIR IS TRAPPING MOISTURE NEAR THE SURFACE.
PATCHY DENSE FOG IS BEING REPORTED THROUGH MOST OF SOUTHWEST LOUISIANA.
A DENSE FOG ADVISORY WILL REMAIN IN EFFECT.
OTHERWISE...A WARM CONVEYOR BELT AIRSTREAM IS BECOMING BETTER
ESTABLISHED WITHIN THE SURFACE LAYER. CAMPECHE AIR IS RIDING IN ON
INCREASING SOUTHERLY WINDS.
THE AFTERNOON READINGS WILL BE RUNNING FROM 10 TO 15 DEGREES ABOVE
NORMAL. THE AFTERNOON HUMIDITIES WILL BE RUNNING WELL ABOVE NORMAL.
FOR TONIGHT...PATCHY FOG IS EXPECTED TO RETURN. OTHERWISE...THE
OVERNIGHT MINIMUMS WILL BE RUNNING FROM 15 TO 20 DEGREES ABOVE NORMAL.
OUTLOOK...
A STRONG CANADIAN FRONT WILL TRAVEL THROUGH THE FORECAST AREA
DURING THE OVERNIGHT HOURS ON SUNDAY.
NUMEROUS SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THIS SYSTEM.
21
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 75 60 78 61 77 / 10 10 10 10 20
KBPT 75 61 78 63 77 / 10 10 20 10 20
KAEX 74 57 77 59 77 / 10 10 10 10 20
KLFT 75 59 78 59 77 / 10 10 10 10 20
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1207 PM CST FRI DEC 7 2012
.UPDATED FOR 18Z AVIATION AND WINTER STORM WATCH...
.DISCUSSION...
EXPANDED THE WINTER STORM WATCH SOUTHWARD A FEW ROWS OF COUNTIES
GIVEN CONTINUED TRENDS OF 12Z MODELS. THINK THE 12Z NAM QPF IS A
BIT TOO BULLISH AND LEANING TOWARD THE GFS. GIVEN THAT...EXPANDED
IT SOUTHWARD TO AREAS WITH ROUGHLY 0.4 INCH QPF WHICH WOULD
TRANSLATE TO AROUND 5 INCHES OF SNOW. IN ADDITION...WITH WINDS
INCREASING SUNDAY...BLOWING SNOW WILL BECOME A PROBLEM PARTICULARLY
OVER THE WESTERN HALF OF MINNESOTA. STILL WILL SEE A DRY SLOT
PUNCH INTO THE SOUTHWEST CWA NEAR MANKATO SUNDAY MORNING WHICH
WOULD LIMIT ACCUMULATION TO PERHAPS 4 INCHES...BUT WINDS WILL BE
MAXIMIZED IN THAT AREA WHICH WOULD BRING A LARGER BLOWING SNOW
THREAT. SOMETHING INTERESTING OF NOTE...A WELL-PERFORMING
EXPERIMENTAL MODEL FAILS TO PRODUCE A LOW WITHIN THE INVERTED
TROUGH OVER CENTRAL MN WHICH RESULTS IN A DEFORMATION BAND FURTHER
SOUTH FROM WILLMAR TO MSP TO EAU CLAIRE. WHILE THIS IS AN OUTLIER
SCENARIO...IT STILL ADDS TO THE POTENTIAL FOR SIGNIFICANT
ACCUMULATIONS FURTHER SOUTH.-BORGHOFF
/PREVIOUS DISCUSSION ISSUED AT 411 AM CST FRI DEC 07 2012/
PLENTY OF CONCERNS THIS MORNING WITH TWO WEATHER SYSTEMS MOVING
THROUGH FROM TODAY THROUGH SUNDAY.
THE FIRST IS A MID LEVEL LOW APPROACHING CENTRAL SD EARLY THIS
MORNING. THIS FEATURE IS PROGGED TO MOVE EAST AND PASS ACROSS
SOUTHERN MN THIS EVENING. ACCOMPANYING THE LOW IS A FAIRLY STRONG
BAND OF FRONTOGENESIS AND OMEGA AT -15 DEG C. THE PROBLEM IS THE
FORCING AND MODEL QPF...ESPECIALLY FROM THE GFS...ARE NOT IN SYNC.
IN ADDITION...THERE IS GOOD CONSENSUS ON A PV MAX MOVING ACROSS
SOUTHERN MN ALONG WITH A 120M HEIGHT FALL CENTER. RAP GUIDANCE
POINTS TO SW AND SOUTH CENTRAL MN FOR THE MOST QPF WHICH AGREES
MUCH BETTER WITH THE FORCING. PRECIP AMOUNTS ARE IN THE .10 TO .25
INCH RANGE WITH THE MOST IN OUR FAR SW MN COUNTIES. THE NAM AND
GFS ARE SIMILAR BUT MUCH FARTHER NORTH. FOLLOWING THE FORCING
SEEMS TO BE THE MOST CORRECT THING TO DO AND THIS WOULD PLACE NEAR
ADVISORY SNOWFALL OVER SW AND PARTS OF SOUTH CENTRAL MN DURING THE
AFTERNOON AND EVENING. THE TREND ON THIS WEATHER SYSTEM OVER THE
PAST TWO NIGHTS HAS BEEN GETTING STRONGER AND TAKING LONGER TO
WEAKEN DURING THE OVERNIGHT HOURS. THERE IS ALSO QUITE THE SNOW
BAND IN WESTERN/CENTRAL SD NORTH OF I-90. THEREFORE..USED
FORECASTER DISCRETION AND ISSUED A WINTER WEATHER ADVISORY FROM
WEST CENTRAL INTO SOUTH CENTRAL MN FOR THIS AFTERNOON AND EVENING.
WE CURRENTLY HAVE 2 TO 2.5 INCHES IN THE ADVISORY AREA...BUT
CONCERNED AMOUNTS MAY BE HIGHER IN THE BAND OF MID LEVEL -FN
VECTOR DIVERGENCE. STILL HAVE SNOW SPREADING ACROSS THE TWIN
CITIES DURING THE AFTERNOON AND EVENING WITH AMOUNTS UP TO ONE
INCH.
THE SECOND CONCERN IS A MUCH STRONGER LOW PRESSURE SYSTEM FORECAST
ACROSS THE REGION SATURDAY NIGHT AND SUNDAY. NAM/GFS/ECMWF STILL
SHOW A MID LEVEL LOW PASSING ACROSS CENTRAL MN AND NORTHERN WI
DURING THIS PERIOD. A BAND OF WAA SNOW WILL PRECEDE THE LOW WITH
DEFORMATION SNOW CONTINUING FROM WEST CENTRAL MN INTO THE
ARROWHEAD ON SUNDAY. THE TOP THREE CIPS ANALOGS ALL HAD 6+ INCHES
OF SNOW ACROSS CENTRAL MN WITH A FOOT OR MORE FOR THE NORTH. THE
TREND ON THIS WEATHER SYSTEM OVER THE PAST FEW NIGHT IS FARTHER
SOUTH WITH THE SFC/MID LEVEL LOW PRESSURE. THIS SYSTEM IS
ACCOMPANIED BY A VERY STRONG PV BOOT SATURDAY NIGHT AND SUNDAY
POINTING INTO WEST CENTRAL AND NORTHERN AREAS OF MN. THE SURFACE
GRADIENT THAT DEVELOPS OVER WESTERN MN SUNDAY MORNING IS ALARMING.
BUFKIT NAM/GFS PROFILE DATA FOR KMOX SHOW WINDS JUST OFF THE
SURFACE IN THE 25-29 KNOT RANGE WITH TOP OF THE CHANNEL IN THE
38-43 KNOT RANGE. DEPENDING ON HOW MUCH SNOW FALLS...AND IF THE
WINDS VERIFY...THIS COULD END UP BEING A BLIZZARD FOR PARTS OF THE
WEST ON SUNDAY. TEMPERATURES WILL ALSO BE STEADY OR FALLING IN
THE TEENS WITH BELOW ZERO TEMPERATURES EXPECTED SUNDAY NIGHT.
AFTER QUITE A BIT OF COLLABORATION WITH KDLH...KARX AND KABR...WE
FELT IT WAS PRUDENT TO ISSUE A WINTER STORM WATCH FOR SATURDAY
NIGHT AND SUNDAY. CURRENT SNOW ACCUMULATION GRIDS ARE IN THE 5 TO
7 INCH RANGE ACROSS CENTRAL MN AND PARTS OF WEST CENTRAL WI.
CURRENTLY HAVE 4 TO 5 INCHES FOR THE TWIN CITIES.
LITTLE TIME SPENT ON LONGER TERM GRIDS WITH THE CRH EXTEND
ACCEPTED. A QUICK GLANCE FOR THE MONDAY THROUGH THURSDAY PERIOD
SHOWS ONLY WEAK WEATHER SYSTEM PASSING BY AND MAINLY TO THE NORTH.
TEMPERATURES BELOW NORMAL FOR MUCH OF NEXT WEEK.
&&
.AVIATION.../18Z TAF ISSUANCE/
MAIN CONCERN WILL BE THE ONSET...INTENSITY..AND DURATION OF
SNOWFALL THAT WILL MOVE EASTWARD ACROSS THE FORECAST AREA TODAY.
AS OF LATE MORNING IFR CONDITIONS WERE ONGOING ACROSS SOUTHWEST
MINNESOTA. EXPECT MAINLY 1 TO 2SM VISBYS...WITH A HALF MILE
POSSIBLE AT TIMES. WINDS WILL BE LIGHT THROUGH THE OVERNIGHT
HOURS...AND GRADUALLY TAKE ON A SOUTHERLY DIRECTION BY LATE
SATURDAY MORNING.
KMSP...
MOVED UP THE ONSET TIME OF THE SNOWFALL AT KMSP GIVEN THE RECENT
TRENDS DEPICTED ON RADAR. TOTAL SNOWFALL SHOULD BE AROUND AN
INCH...AND NOT ANTICIPATING ANY RATES OVER 3/4 IN/HR. LOW CLOUDS
WILL ACCOMPANY THE SNOWFALL...AND SHOULD DROP BELOW 1700 FEET FOR
THE MAJORITY OF THE OVERNIGHT HOURS BEFORE IMPROVING SATURDAY
MORNING.
/OUTLOOK FOR KMSP/
SAT NIGHT...IFR AND -SN WITH POSSIBLE LIFR AND +SN. WINDS SE AT
10KTS.
SUN...IFR AND -SN WITH POSSIBLE LIFR AND +SN EARLY. WINDS SE AT
05KTS BECOMING NW AT 20G30KTS AFTER 18Z.
MON...MVFR WITH -SHSN EARLY...THEN VFR. WINDS W AT 10G15KTS.
TUE...MVFR WITH -SN POSSIBLE. WINDS W AT 10G15KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BLUE
EARTH-BROWN-CHIPPEWA-FARIBAULT-LAC QUI PARLE-LE SUEUR-
MARTIN-NICOLLET-REDWOOD-RENVILLE-SIBLEY-WASECA-WATONWAN-
YELLOW MEDICINE.
WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY
AFTERNOON FOR ANOKA-BENTON-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-STEVENS-SWIFT-TODD-WASHINGTON-WRIGHT-YELLOW
MEDICINE.
WI...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY
EVENING FOR BARRON-CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-
POLK-RUSK-ST. CROIX.
&&
$$
BB/RAH/JRB
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1105 AM CST FRI DEC 7 2012
.UPDATE...
EXPANDED THE WINTER STORM WATCH SOUTHWARD A FEW ROWS OF COUNTIES
GIVEN CONTINUED TRENDS OF 12Z MODELS. THINK THE 12Z NAM QPF IS A
BIT TOO BULLISH AND LEANING TOWARD THE GFS. GIVEN THAT...EXPANDED
IT SOUTHWARD TO AREAS WITH ROUGHLY 0.4 INCH QPF WHICH WOULD
TRANSLATE TO AROUND 5 INCHES OF SNOW. IN ADDITION...WITH WINDS
INCREASING SUNDAY...BLOWING SNOW WILL BECOME A PROBLEM PARTICULARLY
OVER THE WESTERN HALF OF MINNESOTA. STILL WILL SEE A DRY SLOT
PUNCH INTO THE SOUTHWEST CWA NEAR MANKATO SUNDAY MORNING WHICH
WOULD LIMIT ACCUMULATION TO PERHAPS 4 INCHES...BUT WINDS WILL BE
MAXIMIZED IN THAT AREA WHICH WOULD BRING A LARGER BLOWING SNOW
THREAT. SOMETHING INTERESTING OF NOTE...A WELL-PERFORMING
EXPERIMENTAL MODEL FAILS TO PRODUCE A LOW WITHIN THE INVERTED
TROUGH OVER CENTRAL MN WHICH RESULTS IN A DEFORMATION BAND FURTHER
SOUTH FROM WILLMAR TO MSP TO EAU CLAIRE. WHILE THIS IS AN OUTLIER
SCENARIO...IT STILL ADDS TO THE POTENTIAL FOR SIGNIFICANT
ACCUMULATIONS FURTHER SOUTH.
BORGHOFF
&&
.AVIATION... /12Z TAF ISSUANCE/
SOME MINOR ADJUSTMENTS TO GOING FORECAST. MAY SEE A SLOWER START
TIME FARTHER EAST...BUT STILL DROP CEILINGS TO MVFR OVER THE
REGION...MOST LIKELY IFR VSBYS. KRWF MAY SEE IFR CONDITIONS INTO HE
AFTERNOON AS HEAVIER SNOW BAND FORECAST ALONG THE MINNESOTA RIVER
VALLEY...PERHAPS INTO SOUTHERN METRO BY LATE AFTERNOON. WILL HAVE TO
MONITOR BAND AS IT WORKS OVER THE DAKOTAS THIS MORNING. SNOW COMING
IN LATE AFTERNOON/EVENING OVER EASTERN TAF SITES...SHOULD TAPER
FARTHER EAST AS WAVE MOVES THROUGH DRY AIR AND WEAKENS A BIT. SNOW
SHOULD END TO THE WEST EARLY EVENING AND AFTER 06Z TO THE
EAST...WITH MVFR CEILINGS REMAINING FOR NOW AHEAD OF THE NEXT
STRONGER SYSTEM FOR SATURDAY. LIGHT WINDS BECOMING MORE
NORTHEAST/EAST AHEAD OF WAVE AND EVENTUALLY SOUTHEAST TO SOUTH ON
SATURDAY.
KMSP...ONLY MINOR ADJUSTMENT TO TIMING OF SNOW. SHOULD MOVE IN BY
22Z AND EXIT AFTER 06Z2. IFR VSBYS IN HEAVIER SNOW THIS
EVENING...THEN IMPROVING LATE. MAYBE AN INCH ACCUMULATION.
LIGHT WINDS BECOMING NORTHEAST TO EAST DURING THE DAY AND SOUTHEAST
INTO SATURDAY.
/OUTLOOK FOR KMSP/
SAT...MVFR CIGS ENDING IN THE MORNING...THEN VFR. MVFR/IFR CIGS/VIS
DEVELOPING OVERNIGHT WITH SN. WINDS SE AT 10KTS.
SUN...SN ENDING IN THE AFTERNOON...2-4 IN POSSIBLE. MVFR/IFR
CIGS/VIS IN MORNING. MVFR CIGS AFTERNOON. WINDS BCMG NW
20G30KTS.
MON...MVFR CIGS EARLY...BECOMING VFR IN AFTERNOON. WINDS NW 15KTS
IN MORNING...BCMG SW AT 5 KTS IN AFTERNOON.
&&
.PREV DISCUSSION...
/ISSUED 545 AM CST FRI DEC 7 2012/
PLENTY OF CONCERNS THIS MORNING WITH TWO WEATHER SYSTEMS MOVING
THROUGH FROM TODAY THROUGH SUNDAY.
THE FIRST IS A MID LEVEL LOW APPROACHING CENTRAL SD EARLY THIS
MORNING. THIS FEATURE IS PROGGED TO MOVE EAST AND PASS ACROSS
SOUTHERN MN THIS EVENING. ACCOMPANYING THE LOW IS A FAIRLY STRONG
BAND OF FRONTOGENESIS AND OMEGA AT -15 DEG C. THE PROBLEM IS THE
FORCING AND MODEL QPF...ESPECIALLY FROM THE GFS...ARE NOT IN SYNC.
IN ADDITION...THERE IS GOOD CONSENSUS ON A PV MAX MOVING ACROSS
SOUTHERN MN ALONG WITH A 120M HEIGHT FALL CENTER. RAP GUIDANCE
POINTS TO SW AND SOUTH CENTRAL MN FOR THE MOST QPF WHICH AGREES
MUCH BETTER WITH THE FORCING. PRECIP AMOUNTS ARE IN THE .10 TO .25
INCH RANGE WITH THE MOST IN OUR FAR SW MN COUNTIES. THE NAM AND
GFS ARE SIMILAR BUT MUCH FARTHER NORTH. FOLLOWING THE FORCING
SEEMS TO BE THE MOST CORRECT THING TO DO AND THIS WOULD PLACE NEAR
ADVISORY SNOWFALL OVER SW AND PARTS OF SOUTH CENTRAL MN DURING THE
AFTERNOON AND EVENING. THE TREND ON THIS WEATHER SYSTEM OVER THE
PAST TWO NIGHTS HAS BEEN GETTING STRONGER AND TAKING LONGER TO
WEAKEN DURING THE OVERNIGHT HOURS. THERE IS ALSO QUITE THE SNOW
BAND IN WESTERN/CENTRAL SD NORTH OF I-90. THEREFORE..USED
FORECASTER DISCRETION AND ISSUED A WINTER WEATHER ADVISORY FROM
WEST CENTRAL INTO SOUTH CENTRAL MN FOR THIS AFTERNOON AND EVENING.
WE CURRENTLY HAVE 2 TO 2.5 INCHES IN THE ADVISORY AREA...BUT
CONCERNED AMOUNTS MAY BE HIGHER IN THE BAND OF MID LEVEL -FN
VECTOR DIVERGENCE. STILL HAVE SNOW SPREADING ACROSS THE TWIN
CITIES DURING THE AFTERNOON AND EVENING WITH AMOUNTS UP TO ONE
INCH.
THE SECOND CONCERN IS A MUCH STRONGER LOW PRESSURE SYSTEM FORECAST
ACROSS THE REGION SATURDAY NIGHT AND SUNDAY. NAM/GFS/ECMWF STILL
SHOW A MID LEVEL LOW PASSING ACROSS CENTRAL MN AND NORTHERN WI
DURING THIS PERIOD. A BAND OF WAA SNOW WILL PRECEDE THE LOW WITH
DEFORMATION SNOW CONTINUING FROM WEST CENTRAL MN INTO THE
ARROWHEAD ON SUNDAY. THE TOP THREE CIPS ANALOGS ALL HAD 6+ INCHES
OF SNOW ACROSS CENTRAL MN WITH A FOOT OR MORE FOR THE NORTH. THE
TREND ON THIS WEATHER SYSTEM OVER THE PAST FEW NIGHT IS FARTHER
SOUTH WITH THE SFC/MID LEVEL LOW PRESSURE. THIS SYSTEM IS
ACCOMPANIED BY A VERY STRONG PV BOOT SATURDAY NIGHT AND SUNDAY
POINTING INTO WEST CENTRAL AND NORTHERN AREAS OF MN. THE SURFACE
GRADIENT THAT DEVELOPS OVER WESTERN MN SUNDAY MORNING IS ALARMING.
BUFKIT NAM/GFS PROFILE DATA FOR KMOX SHOW WINDS JUST OFF THE
SURFACE IN THE 25-29 KNOT RANGE WITH TOP OF THE CHANNEL IN THE
38-43 KNOT RANGE. DEPENDING ON HOW MUCH SNOW FALLS...AND IF THE
WINDS VERIFY...THIS COULD END UP BEING A BLIZZARD FOR PARTS OF THE
WEST ON SUNDAY. TEMPERATURES WILL ALSO BE STEADY OR FALLING IN
THE TEENS WITH BELOW ZERO TEMPERATURES EXPECTED SUNDAY NIGHT.
AFTER QUITE A BIT OF COLLABORATION WITH KDLH...KARX AND KABR...WE
FELT IT WAS PRUDENT TO ISSUE A WINTER STORM WATCH FOR SATURDAY
NIGHT AND SUNDAY. CURRENT SNOW ACCUMULATION GRIDS ARE IN THE 5 TO
7 INCH RANGE ACROSS CENTRAL MN AND PARTS OF WEST CENTRAL WI.
CURRENTLY HAVE 4 TO 5 INCHES FOR THE TWIN CITIES.
LITTLE TIME SPENT ON LONGER TERM GRIDS WITH THE CRH EXTEND
ACCEPTED. A QUICK GLANCE FOR THE MONDAY THROUGH THURSDAY PERIOD
SHOWS ONLY WEAK WEATHER SYSTEM PASSING BY AND MAINLY TO THE NORTH.
TEMPERATURES BELOW NORMAL FOR MUCH OF NEXT WEEK.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BLUE
EARTH-BROWN-CHIPPEWA-FARIBAULT-LAC QUI PARLE-LE SUEUR-
MARTIN-NICOLLET-REDWOOD-RENVILLE-SIBLEY-WASECA-WATONWAN-
YELLOW MEDICINE.
WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY
AFTERNOON FOR ANOKA-BENTON-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-STEVENS-SWIFT-TODD-WASHINGTON-WRIGHT-YELLOW
MEDICINE.
WI...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY
EVENING FOR BARRON-CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-
POLK-RUSK-ST. CROIX.
&&
$$
RAH/DWE
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1247 PM EST FRI DEC 7 2012
.SYNOPSIS...
A WARM FRONT WILL BRING RAIN TO MUCH OF THE REGION TODAY. THIS
WILL MARK THE BEGINNING OF A RATHER UNSETTLED PERIOD WITH
SCATTERED SHOWERS POSSIBLE EACH DAY AS SEVERAL DISTURBANCES
INTERACT WITH THE STALLED FRONT. TEMPERATURES THROUGH THE WEEKEND
WILL REMAIN ABOVE NORMAL AS ANY COLD AIR REMAINS DISPLACED WELL TO
OUR WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
12 PM UPDATE...ALL THE FREEZING RAIN ADV HAVE EXPIRED AS TEMPS ARE
NOW IN THE LOWER TO MIDDLE 30S. IN THE HIGHER ELEVATIONS OF
OTSEGO, DELAWARE AND SULLIVAN COUNTIES POCKETS OF FREEZING RAIN
ARE STILL POSSIBLE THROUGH EARLY AFTERNOON.
10 AM UPDATE...BASED ON LOCAL MESONET OBS ACROSS NE PA AND PARTS OF
THE SOUTHERN TIER AND WESTERN CATSKILLS DECIDED TO EXTEND THE FREEZING
RAIN ADV UNTIL MIDDAY. THE HIGHER ELEVATIONS PRIMARILY ABOVE 1200 FT
AND THE WESTERN CATSKILLS INCLUDING SULLIVAN COUNTY WILL SEE THE
MOST FREEZING RAIN DURING THE NEXT COUPLE OF HOURS. BY EARLY
AFTERNOON, COMBINATION OF WARMING ALOFT AND SFC TEMPS RISING
ABOVE THE FREEZING MARK WILL END THE FREEZING RAIN THREAT.
830 AM UPDATE...ISSUED FREEZING RAIN ADVISORY FOR TIOGA, BROOME,
CHENANGO AND OTSEGO COUNTIES UNTIL 11 AM. LIGHT PRECIP IS NOW
SPREADING ACROSS THE ABOVE MENTIONED AREAS WITH TEMPS NEAR
FREEZING AND DEW POINTS IN THE LOWER TO MIDDLE 20S. THE LOW
DEW POINTS WILL ALLOW TEMPS TO REMAIN STEADY OR DROP SLIGHTLY AS THE
LIGHT PRECIP BEGINS WITH AREAS OF FREEZING RAIN LIKELY UNTIL LATE
MORNING ESPECIALLY AT THE HIGHER ELEVATIONS. BY LATE MORNING WARM
LAYER ALOFT AND DIURNAL HEATING WILL END THE THREAT FOR FREEZING
RAIN.
650 AM UPDATE...
BASED ON TEMP TRENDS FROM LOCAL MESONET OBSERVATIONS...HAVE
ELECTED TO GO WITH AN FREEZING RAIN ADVISORY FOR ALL OF NE PA AND
THE CATSKILLS OF EASTERN NY. AS PRECIP CONTINUES TO MOVE
IN...CANNOT RULE OUT VERY LIGHT ICE ACCUMULATIONS FOR ELEVATIONS
GRATER THAN 1000 FEET. FOR NOW HAVE HELD OFF FOR THE CENTRAL AND
EASTERN SOUTHERN TIER AS BULK OF INITIAL BATCH OF RA WILL LIKELY
PASS JUST TO THE SOUTH. AFTER THIS...TEMPS SHOULD WARM ABOVE
FREEZING HOPEFULLY NEGATING ANY FREEZING RAIN CONCERNS FOR THESE
AREAS. NO OTHER SIGNIFICANT CHANGES NEEDED AT THE PRESENT TIME.
PREVIOUS NEAR TERM DISCUSSION...
MAIN CONCERN IN THE NEAR TERM CONTINUES TO BE APPROACHING FRONTAL
WAVE AND ASSOCIATED PRECIP LATER THIS MORNING. LATEST REGIONAL
RADAR IMAGES SHOWING LEADING EDGE OF RAIN NOW EAST OF PIT AND
WORKING TOWARDS JST IN SW PA. AHEAD OF THIS PRECIP...A SUBSTANTIAL
AMOUNT OF DRY AIR REMAINS IN PLACE AS EVIDENCED BY 00Z PIT AND BUF
RAOBS. PRECIP IS BEING FORCED LARGELY BY ISENTROPIC ASCENT ALONG
THE 285-295 THETA SURFACES AS INCREASING WINDS AT THE 925 AND
850-MB LEVELS ASCEND THE APPROACHING FRONTAL BOUNDARY. WITH THE
AMOUNT OF DRY AIR IN PLACE...HAVE ELECTED TO TRIM BACK TIMING OF
PRECIP ARRIVAL TIME FROM THE TWIN TIERS AND POINTS SOUTH. IT NOW
APPEARS THAT PRECIP WILL NOT MAKE INTO THE CWA BEFORE 12Z AS
SUFFICIENT TIME WILL BE REQUIRED TO MOISTEN THE ATMOSPHERIC
COLUMN.
THE ABOVE SAID...MAIN ATTENTION CONTINUES TO FOCUS ON FZRA
POTENTIAL AS INITIAL BATCH OF PRECIP MOVES IN. CLOSE INSPECTION OF
BOTH RR AND WRF THETA SURFACES AND MODEL CONDENSATION PRESSURE
DEFICITS REVEALS APPROPRIATE SATURATION ALONG THE 285 SFC WILL NOT
OCCUR UNTIL 12-13Z AT THE EARLIEST. BY THIS TIME...DIURNAL TEMPS
SHOULD BEGIN REBOUNDING AS DAYTIME HEATING COMMENCES WHICH SHOULD
ONLY RESULT IN A VERY BRIEF PERIOD WHERE SFC TEMPS MAY BE COLD
ENOUGH TO SUPPORT FZRA ALONG THE ELEVATED SURFACES OF THE NORTHERN
TIER AND LOWER WYOMING VALLEY REGIONS OF NE PA.
BEYOND THIS...RA WILL GRADUALLY OVERSPREAD THE REGION THROUGH THE
MORNING AND AFTERNOON HRS. UP NORTH...PRECIP WILL LIKELY HOLD OFF
UNTIL EARLY AFTERNOON AFTER WHICH...WEAK SHORTWAVE ENERGY RIDING
ALONG THE FRONT SHOULD EVENTUALLY ALLOW PRECIP TO EXTEND AS FAR
NORTH AS THE SYR AND RME AREAS. RAINFALL AMOUNTS THROUGH THE DAY WILL
LIKELY REMAIN UNDER 2 TENTH OF AN INCH AT MOST LOCATIONS...WITH
EVEN LOWER AMOUNTS EXPECTED ACROSS THE NORTHERN FINGER LAKES AND
WESTERN MOHAWK VALLEY AS MAX FRONTAL FORCING REMAINS SOUTH. HIGH
TEMPS WILL TOP OUT IN LOWER 40S ACROSS THE NORTHERN FINGER LAKES
AND LAKE PLAIN...WITH MIDDLE TO UPPER 30S DOMINATE ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
FAIRLY ACTIVE PERIOD CONTINUING TO TAKE SHAPE THROUGH THE UPCOMING
WEEKEND AS THE NEXT IN A SERIES OF SFC LOWS LIFTS NORTH ALONG A
STALLED FRONT TO OUR WEST BEGINNING TONIGHT. THAT SAID...RA ACROSS
THE REGION SHOULD BECOME A LITTLE BIT MORE ORGANIZED INITIALLY
THIS EVENING AS SFC LOW LIFTS NORTH FROM THE LWR OHIO VLY INTO THE
LWR GREAT LAKES. AS THIS OCCURS...FORCING CONTRIBUTIONS FROM BOTH
THE POLAR AND SUBTROPICAL JETS WILL TRANSCEND ACROSS THE REGION
WITH ADDITIONAL FORCING ARRIVING FROM CONTINUED ISENTROPIC ASCENT
ALONG THE PREVIOUSLY MENTIONED WARM FRONT. THERMAL PROFILES FROM
ACROSS THE REGION INDICATE SFC TEMPS WILL REMAIN ABOVE FREEZING AS
WARM AIR ADVECTION CONTINUES. THIS SHOULD KEEP ANY PRECIP IN
LIQUID FORM.
SFC LOW PROGGED TO PASS TO OUR WEST ON SATURDAY WITH INCREASING
SOUTHWESTERLY FLOW FINALLY ALLOWING WARM FRONT TO LIFT NORTH
THROUGH THE ENTIRE CWA. AS A RESULT...EXPECT A WARMER DAY WITH
TEMPS TOPPING OUT IN THE UPPER 40S TO LOWER 50S ACROSS MUCH OF THE
AREA. WITH BEST FORCING FOR ASCENT ARRIVING FROM A NORTHERN STREAM
SHORTWAVE ACROSS THE UPPER GREAT LAKES...BEST CHANCES FOR
ORGANIZED PRECIP WILL LIKELY REMAIN NORTH AND WEST OF OUR AREA.
DESPITE THIS HOWEVER...SHORT TERM MODELS INDICATE A DEVELOPING SECONDARY
LOW OFF THE NJ COAST THROUGH THE DAY WHICH COMBINED WITH A WEAKER
SHORTWAVE IMPULSE PASSING OVERHEAD SHOULD KEEP THE CHC FOR SHWRS
ACROSS THE AREA THROUGH THE DAY. MAIN LOW EXPECTED TO PASS TO OUR
NORTH OVERNIGHT WHICH WILL SEND A COLD FRONT SOUTH ACROSS THE FCST
AREA. MODELS AGREE A QUICK COOL DOWN WILL OCCUR AFTER PASSAGE WITH
850-MB TEMPS QUICKLY FALLING TO -4C ACROSS THE FAR NORTH. HIGHLY
SHEARED FLOW COMBINED WITH THE INFLUX OF DRY AIR AND ONLY MARGINAL
TEMP DIFFERENCES WILL NEGATE ANY LAKE RESPONSE AND THUS HAVE DRIED
THINGS OUT FROM NORTH TO SOUTH OVERNIGHT EARLY SUN.
NEXT MORE POTENT WAVE TO LIFT NORTH FROM THE OHIO VLY ON SUN WHICH
WILL ONCE AGAIN LIFT THE FRONT BACK NORTH THROUGH BEGINNING SUN
NGT. AS SUCH...EXPECT INCREASING CHANCES FOR RAIN ONCE AGAIN SUN
AFTERNOON AND EVENING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
LOW PRES WILL TRACK NEWD INTO ERN CANADA ON MONDAY...SWINGING A
CDFNT THUR THE RGN. AFTER FROPA...SOME LINGERING -SHSN WILL BE
PSBL IN THE NW FLOW ON TUE ACRS CNTRL NY. OTRW...A DRY PD XPCTD AS
HI PRES SETS UP OVER THE MID ATLC RGN WITH TEMPS AVERAGING ARND OR
SLIGHTLY ABV SEASONAL NORMS. UTILIZED HPC GRIDS FOR THE MED RNG
FCST BUT TRENDED MORE OPTIMISTIC FOR CLD CVR GIVEN LATEST
GUIDANCE.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
WDSPRD IFR/MVFR XPCTD AT ALL SITES THRU 18Z SAT IN -RA/DZ/BR/CIGS.
AT 18Z SYR/RME ARE STILL VFR BUT XPCT MVFR CIGS TO MOV INTO THAT
AREA AFTER 21Z. ELSEWHERE IFR/MVFR FIRMLY ENTRENCHED ACRS THE FCST
AREA...AND CONDITIONS AT MOST LOCATIONS ACRS THE SRN TIER AND NE
PA WILL GO BLO AIRPORT MINS. 2ND WAVE LATER TNGT WILL DELIVER
ANOTHER ROUND OF RAIN...WITH MOST OF THE STEADIER PCPN EXITING THE
RGN BY DAYBREAK WITH RESIDUAL LOW CIGS/-DZ PERSISTING INTO THE
EARLY AFTN HRS. WINDS WILL BE ON THE LGT SIDE...GNRLY FROM THE S
OR SE ARND 5 KTS.
OUTLOOK...
SATURDAY NIGHT...MVFR MAINLY ACRS CNTRL NY.
SUNDAY...VFR.
SUNDAY NIGHT/MON...IFR/MVFR IN RAIN.
TUESDAY...PATCHY MVFR ACRS CNTRL NY.
WED...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG/RRM
NEAR TERM...CMG/RRM
SHORT TERM...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1215 PM EST FRI DEC 7 2012
.SYNOPSIS...
A WARM FRONT WILL BRING RAIN TO MUCH OF THE REGION TODAY. THIS
WILL MARK THE BEGINNING OF A RATHER UNSETTLED PERIOD WITH
SCATTERED SHOWERS POSSIBLE EACH DAY AS SEVERAL DISTURBANCES
INTERACT WITH THE STALLED FRONT. TEMPERATURES THROUGH THE WEEKEND
WILL REMAIN ABOVE NORMAL AS ANY COLD AIR REMAINS DISPLACED WELL TO
OUR WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
12 PM UPDATE...ALL THE FREEZING RAIN ADV HAVE EXPIRED AS TEMPS ARE
NOW IN THE LOWER TO MIDDLE 30S. IN THE HIGHER ELEVATIONS OF
OTSEGO, DELAWARE AND SULLIVAN COUNTIES POCKETS OF FREEZING RAIN
ARE STILL POSSIBLE THROUGH EARLY AFTERNOON.
10 AM UPDATE...BASED ON LOCAL MESONET OBS ACROSS NE PA AND PARTS OF
THE SOUTHERN TIER AND WESTERN CATSKILLS DECIDED TO EXTEND THE FREEZING
RAIN ADV UNTIL MIDDAY. THE HIGHER ELEVATIONS PRIMARILY ABOVE 1200 FT
AND THE WESTERN CATSKILLS INCLUDING SULLIVAN COUNTY WILL SEE THE
MOST FREEZING RAIN DURING THE NEXT COUPLE OF HOURS. BY EARLY
AFTERNOON, COMBINATION OF WARMING ALOFT AND SFC TEMPS RISING
ABOVE THE FREEZING MARK WILL END THE FREEZING RAIN THREAT.
830 AM UPDATE...ISSUED FREEZING RAIN ADVISORY FOR TIOGA, BROOME,
CHENANGO AND OTSEGO COUNTIES UNTIL 11 AM. LIGHT PRECIP IS NOW
SPREADING ACROSS THE ABOVE MENTIONED AREAS WITH TEMPS NEAR
FREEZING AND DEW POINTS IN THE LOWER TO MIDDLE 20S. THE LOW
DEW POINTS WILL ALLOW TEMPS TO REMAIN STEADY OR DROP SLIGHTLY AS THE
LIGHT PRECIP BEGINS WITH AREAS OF FREEZING RAIN LIKELY UNTIL LATE
MORNING ESPECIALLY AT THE HIGHER ELEVATIONS. BY LATE MORNING WARM
LAYER ALOFT AND DIURNAL HEATING WILL END THE THREAT FOR FREEZING
RAIN.
650 AM UPDATE...
BASED ON TEMP TRENDS FROM LOCAL MESONET OBSERVATIONS...HAVE
ELECTED TO GO WITH AN FREEZING RAIN ADVISORY FOR ALL OF NE PA AND
THE CATSKILLS OF EASTERN NY. AS PRECIP CONTINUES TO MOVE
IN...CANNOT RULE OUT VERY LIGHT ICE ACCUMULATIONS FOR ELEVATIONS
GRATER THAN 1000 FEET. FOR NOW HAVE HELD OFF FOR THE CENTRAL AND
EASTERN SOUTHERN TIER AS BULK OF INITIAL BATCH OF RA WILL LIKELY
PASS JUST TO THE SOUTH. AFTER THIS...TEMPS SHOULD WARM ABOVE
FREEZING HOPEFULLY NEGATING ANY FREEZING RAIN CONCERNS FOR THESE
AREAS. NO OTHER SIGNIFICANT CHANGES NEEDED AT THE PRESENT TIME.
PREVIOUS NEAR TERM DISCUSSION...
MAIN CONCERN IN THE NEAR TERM CONTINUES TO BE APPROACHING FRONTAL
WAVE AND ASSOCIATED PRECIP LATER THIS MORNING. LATEST REGIONAL
RADAR IMAGES SHOWING LEADING EDGE OF RAIN NOW EAST OF PIT AND
WORKING TOWARDS JST IN SW PA. AHEAD OF THIS PRECIP...A SUBSTANTIAL
AMOUNT OF DRY AIR REMAINS IN PLACE AS EVIDENCED BY 00Z PIT AND BUF
RAOBS. PRECIP IS BEING FORCED LARGELY BY ISENTROPIC ASCENT ALONG
THE 285-295 THETA SURFACES AS INCREASING WINDS AT THE 925 AND
850-MB LEVELS ASCEND THE APPROACHING FRONTAL BOUNDARY. WITH THE
AMOUNT OF DRY AIR IN PLACE...HAVE ELECTED TO TRIM BACK TIMING OF
PRECIP ARRIVAL TIME FROM THE TWIN TIERS AND POINTS SOUTH. IT NOW
APPEARS THAT PRECIP WILL NOT MAKE INTO THE CWA BEFORE 12Z AS
SUFFICIENT TIME WILL BE REQUIRED TO MOISTEN THE ATMOSPHERIC
COLUMN.
THE ABOVE SAID...MAIN ATTENTION CONTINUES TO FOCUS ON FZRA
POTENTIAL AS INITIAL BATCH OF PRECIP MOVES IN. CLOSE INSPECTION OF
BOTH RR AND WRF THETA SURFACES AND MODEL CONDENSATION PRESSURE
DEFICITS REVEALS APPROPRIATE SATURATION ALONG THE 285 SFC WILL NOT
OCCUR UNTIL 12-13Z AT THE EARLIEST. BY THIS TIME...DIURNAL TEMPS
SHOULD BEGIN REBOUNDING AS DAYTIME HEATING COMMENCES WHICH SHOULD
ONLY RESULT IN A VERY BRIEF PERIOD WHERE SFC TEMPS MAY BE COLD
ENOUGH TO SUPPORT FZRA ALONG THE ELEVATED SURFACES OF THE NORTHERN
TIER AND LOWER WYOMING VALLEY REGIONS OF NE PA.
BEYOND THIS...RA WILL GRADUALLY OVERSPREAD THE REGION THROUGH THE
MORNING AND AFTERNOON HRS. UP NORTH...PRECIP WILL LIKELY HOLD OFF
UNTIL EARLY AFTERNOON AFTER WHICH...WEAK SHORTWAVE ENERGY RIDING
ALONG THE FRONT SHOULD EVENTUALLY ALLOW PRECIP TO EXTEND AS FAR
NORTH AS THE SYR AND RME AREAS. RAINFALL AMOUNTS THROUGH THE DAY WILL
LIKELY REMAIN UNDER 2 TENTH OF AN INCH AT MOST LOCATIONS...WITH
EVEN LOWER AMOUNTS EXPECTED ACROSS THE NORTHERN FINGER LAKES AND
WESTERN MOHAWK VALLEY AS MAX FRONTAL FORCING REMAINS SOUTH. HIGH
TEMPS WILL TOP OUT IN LOWER 40S ACROSS THE NORTHERN FINGER LAKES
AND LAKE PLAIN...WITH MIDDLE TO UPPER 30S DOMINATE ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
FAIRLY ACTIVE PERIOD CONTINUING TO TAKE SHAPE THROUGH THE UPCOMING
WEEKEND AS THE NEXT IN A SERIES OF SFC LOWS LIFTS NORTH ALONG A
STALLED FRONT TO OUR WEST BEGINNING TONIGHT. THAT SAID...RA ACROSS
THE REGION SHOULD BECOME A LITTLE BIT MORE ORGANIZED INITIALLY
THIS EVENING AS SFC LOW LIFTS NORTH FROM THE LWR OHIO VLY INTO THE
LWR GREAT LAKES. AS THIS OCCURS...FORCING CONTRIBUTIONS FROM BOTH
THE POLAR AND SUBTROPICAL JETS WILL TRANSCEND ACROSS THE REGION
WITH ADDITIONAL FORCING ARRIVING FROM CONTINUED ISENTROPIC ASCENT
ALONG THE PREVIOUSLY MENTIONED WARM FRONT. THERMAL PROFILES FROM
ACROSS THE REGION INDICATE SFC TEMPS WILL REMAIN ABOVE FREEZING AS
WARM AIR ADVECTION CONTINUES. THIS SHOULD KEEP ANY PRECIP IN
LIQUID FORM.
SFC LOW PROGGED TO PASS TO OUR WEST ON SATURDAY WITH INCREASING
SOUTHWESTERLY FLOW FINALLY ALLOWING WARM FRONT TO LIFT NORTH
THROUGH THE ENTIRE CWA. AS A RESULT...EXPECT A WARMER DAY WITH
TEMPS TOPPING OUT IN THE UPPER 40S TO LOWER 50S ACROSS MUCH OF THE
AREA. WITH BEST FORCING FOR ASCENT ARRIVING FROM A NORTHERN STREAM
SHORTWAVE ACROSS THE UPPER GREAT LAKES...BEST CHANCES FOR
ORGANIZED PRECIP WILL LIKELY REMAIN NORTH AND WEST OF OUR AREA.
DESPITE THIS HOWEVER...SHORT TERM MODELS INDICATE A DEVELOPING SECONDARY
LOW OFF THE NJ COAST THROUGH THE DAY WHICH COMBINED WITH A WEAKER
SHORTWAVE IMPULSE PASSING OVERHEAD SHOULD KEEP THE CHC FOR SHWRS
ACROSS THE AREA THROUGH THE DAY. MAIN LOW EXPECTED TO PASS TO OUR
NORTH OVERNIGHT WHICH WILL SEND A COLD FRONT SOUTH ACROSS THE FCST
AREA. MODELS AGREE A QUICK COOL DOWN WILL OCCUR AFTER PASSAGE WITH
850-MB TEMPS QUICKLY FALLING TO -4C ACROSS THE FAR NORTH. HIGHLY
SHEARED FLOW COMBINED WITH THE INFLUX OF DRY AIR AND ONLY MARGINAL
TEMP DIFFERENCES WILL NEGATE ANY LAKE RESPONSE AND THUS HAVE DRIED
THINGS OUT FROM NORTH TO SOUTH OVERNIGHT EARLY SUN.
NEXT MORE POTENT WAVE TO LIFT NORTH FROM THE OHIO VLY ON SUN WHICH
WILL ONCE AGAIN LIFT THE FRONT BACK NORTH THROUGH BEGINNING SUN
NGT. AS SUCH...EXPECT INCREASING CHANCES FOR RAIN ONCE AGAIN SUN
AFTERNOON AND EVENING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
430 AM UPDATE...
NO CHGS NEEDED TO LONG TERM AT THIS TIME AS FRONT MVS THRU MON
EVNG WITH LKLY RAIN SHOWERS. NW FLOW KICKS IN FOLLOWING FROPA TO RESULT
IN LK EFFECT PCPN. BOTH 12Z AND NOW 00Z EC INDICATE DVLPNG SFC
LOPRES RIDING UP ALONG SFC BNDRY JUST OFF THE EAST COAST BY EARLY
WEEK, ALTHO NO OTHER MED RANGE MODELS HV THIS FEATURE.
PREV DISCUSSION BLO...
MEDIUM RANGE MODELS CONTINUE TO SHOW FAIR AGREEMENT THROUGH THE
EXTENDED PERIOD.
SUNDAY NIGHT THROUGH MONDAY, SFC LOW PRES WILL TRACK FROM THE OHIO
VALLEY NORTHEAST ACROSS LAKE ERIE INTO NEARBY SOUTHERN ONTARIO.
WILL CARRY LIKELY POPS BOTH PERIODS WITH RAIN LIKELY SUNDAY NIGHT
FOLLOWED BY RAIN SHOWERS ON MONDAY AS TRAILING COLD FRONT CROSSES
AREA MONDAY AFTERNOON AND EVENING. THROUGH MONDAY EVENING TEMPS
WILL REMAIN WARM ENOUGH FOR JUST LIQUID PRECIP TO FALL. MONDAY
NIGHT AS TEMPS LOWER UNDER CAA AND NORTHWEST FLOW, A WEAK LAKE
RESPONSE MAY OCCUR INTO TUESDAY.
TUESDAY NIGHT THROUGH THURSDAY, LOOKS DRY WITH SFC HIGH PRES
STRETCHING FROM THE MID ATLANTIC REGION INTO NEW ENGLAND.
TEMPS THROUGH THE PERIOD WILL START WELL ABOVE NORMAL THEN FALL TO
SEASONAL LEVELS TUESDAY AND WEDNESDAY BEFORE MODERATING AGAIN ON
THURSDAY.
&&
.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
12Z UPDATE...
VFR INITIALLY WILL GIVE WAY TO MVFR CIGS LATE THIS MORNING. AS
PCPN MOVES FROM SOUTH TO NORTH IT WILL BRING MVFR VSBYS TO
TERMINALS AFTER 18Z. LIGHT RAIN WILL CONTINUE THROUGH THE DAY WITH
MVFR CONDITIONS EXPECTED. HIGHER TERMINALS WILL LIKELY SEE THESE
CIGS DECREASE TO IFR AFTER 05Z AS LOW LEVEL MOISTURE REMAINS
ENTRENCHED ACROSS THE AREA.
SOUTH WINDS AROUND 5 KTS WILL INCREASE TO NEAR 10KTS THIS
AFTERNOON THEN DIMINISH TO LGT/VRB AFTER 06Z.
OUTLOOK...
SATURDAY...MVFR IN SHRA.
SATURDAY NIGHT/SUNDAY MORNING...PRIMARILY VFR.
SUNDAY AFTERNOON THROUGH MONDAY EVENING...RESTRICTIONS EXPECTED IN
RAIN.
TUESDAY...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG/RRM
NEAR TERM...CMG/RRM
SHORT TERM...CMG
LONG TERM...PVN/RRM
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
357 PM EST FRI DEC 7 2012
.SYNOPSIS...
THE WEATHER PATTERN WILL REMAIN UNSETTLED THROUGH THE WEEKEND AS
WAVES OF LOW PRESSURE AND ASSOCIATED FRONTAL SYSTEMS MOVE ACROSS
THE GREAT LAKES AND THE OHIO VALLEY REGION. TEMPERATURES WILL
REMAIN ABOVE NORMAL THROUGH THE WEEKEND FOLLOWED BY MUCH COLDER
TEMPERATURES BY EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
LOCAL AND MOSAIC RADAR CONTINUE TO SHOW RAIN ACROSS THE REGION.
THIS PCPN WAS THE RESULT OF A MOIST AIRMASS IN PLACE COUPLED WITH
LOW LEVEL JET FORCING AND WEAK EMBEDDED DISTURBANCES WITHIN THE
WEST/SOUTHWEST FLOW ALOFT. FOR TONIGHT...A WEAK AREA OF LOW
PRESSURE IS FORECAST TO RIPPLE ALONG A FRONTAL BOUNDARY NEAR OUR
NORTHWEST...BEING PERTURBED BY A LITTLE STRONGER S/WV PUSHES ACRS
THE GREAT LAKES. HAVE GONE WITH MAINLY CATEGORICAL POPS THIS
EVENING...ALTHOUGH THE LATEST HRRR SUGGESTS THAT WIDESPREAD PCPN
MAY BRIEFLY TAPER LATE THIS EVENING/EARLY MORNING BEFORE THE WAVE
OF LOW PRESSURE ARRIVES AND BRINGS ANOTHER ROUND OF RAIN. WILL
CONTINUE TO MONITOR FOR POTENTIAL SHORT TERM ENHANCEMENT. THE
OTHER WEATHER ISSUE TONIGHT WILL BE FOG POTENTIAL. DENSE FOG
FORMED LAST NIGHT ACRS THE WHITEWATER AND MIAMI RIVER VALLEYS AS
WELL AS INTO CENTRAL OHIO. THIS COULD HAPPEN AGAIN ANYWHERE ACRS
THE AREA TONIGHT IF PCPN TAPERS OFF LONG ENOUGH AND WINDS STAY
RELATIVELY LIGHT. DUE TO UNCERTAINTY...HAVE PLACED AREAS OF FOG IN
THE FORECAST AND UPDATED THE HWO PRODUCT FOR POTENTIAL DENSE FOG
OVERNIGHT IF CONDITIONS COME TOGETHER. TEMPERATURES TONIGHT WILL
EITHER REMAIN STEADY STATE OR SLOWLY RISE AHEAD OF THE APPROACHING
LOW PRESSURE WAVE.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
MODELS ARE IN FAIRLY DECENT AGREEMENT IN TERMS OF PLACEMENT...MOVEMENT
AND TIMING OF MAJOR SYNOPTIC SCALE SYSTEMS THROUGH THE SHORT TERM.
HAVE TAKEN A BLEND OF THE NAM...GFS AND ECMWF.
WAVE OF LOW PRESSURE WILL PUSH OFF TO THE NORTHEAST ON SATURDAY.
THIS WILL ALLOW A COLD FRONT TO SAG SOUTHEAST INTO THE REGION.
MODELS SUGGEST THAT THE BEST CHANCE OF PCPN ON SATURDAY WILL BE
ALONG AND AHEAD OF THE FRONT. THUS...HAVE LIKELY POPS GOING FOR
THE ERN/SRN LOCATIONS...MAINLY FOR THE FIRST PART OF THE DAY.
FOR SATURDAY NIGHT...IT LOOKS LIKE THE NRN LOCATIONS WILL HAVE A
RESPITE IN THE PCPN AS COLD FRONTAL SETTLES SOUTH OF THE OHIO
RIVER BEFORE MOVING BACK AS A WARM FRONT ON SUNDAY.
FOR SUNDAY INTO SUNDAY NIGHT...A MORE SIGNIFICANT S/WV IS EXPECTED
TO MOVE FROM THE CENTRAL PLAINS INTO THE GREAT LAKES. THIS
SCENARIO WILL PERTURB A WAVE OF LOW PRESSURE OVER THE MID MS VLY.
THIS PROCESS WILL PUSH OLD FRONTAL BOUNDARY NORTH THROUGH THE
REGION ON SUNDAY. RETURN MOISTURE AND A MODEST LOW LEVEL JET WILL
INCREASE SHOWERS FROM SOUTH TO NORTH DURING THE DAY. THERE SHOULD
BE ENOUGH INSTABILITY TO MENTION THUNDER. THE SFC LOW WILL DEEPEN
AS TI MOVE NE SUNDAY NIGHT...DRAGGING A COLD FRONT SE INTO THE
REGION. LARGE SCALE FRONTAL CONVERGENCE AND UPPER SUPPORT WILL
RESULT IN WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS.
THERE HAS BEEN SOME CONCERN ON HOW MUCH RAIN THE REGION WILL
RECEIVE THROUGH MONDAY DUE TO THE CUMULATIVE EFFECTS OF THE
WEATHER SYSTEMS MOVING THROUGH THE GREAT LAKES AND OHIO VALLEY. IT
APPEARS THAT AN ADDITIONAL 1 TO 2 INCHES ARE EXPECTED TONIGHT
THROUGH MONDAY WITH THE HEAVIEST AMOUNTS OCCURRING ALONG AND SE OF
I-71. GIVEN THAT NOVEMBER WAS DRY AND RIVER/STREAMS ARE STILL
FAIRLY LOW...BELIEVE THAT THE ADDITIONAL RAINFALL WILL NOT LEAD TO
ANY SUBSTANTIAL FLOODING ISSUES...ESPECIALLY WHEN IT COMES TO MAIN
STEM RIVERS. ANY POTENTIAL FLOODING WOULD LIKELY BE MESOSCALE
DRIVEN SUNDAY AFTERNOON AND NIGHT WHICH COULD LEAD TO MINOR ISSUES
IF THE SAME LOCATIONS RECEIVE ROUNDS OF MODERATE TO LOCALLY HEAVY
RAINFALL.
AS FOR TEMPERATURES...HAVE GENERALLY USED A NON-DIURNAL APPROACH
THROUGH THE PERIOD WITH A BLEND OF THE 2 M RAW NAM...GFS AND ECMWF.
IT WILL BE ABOVE NORMAL THROUGH THE WEEKEND WITH HIGHS IN THE 50S
TO THE LOWER 60S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
A WET WEATHER PERIOD WILL COME TO AN END MONDAY...LEADING TO DRY
CONDITIONS AND INCREASING TEMPERATURES THROUGH THE REST OF THE WEEK.
THE OVERALL MODEL TREND IN THE PAST 24 HOURS HAS BEEN FOR A SLIGHTLY
EARLIER COLD FRONTAL PASSAGE ON MONDAY MORNING. THE TIMING
DIFFERENCES ARE STILL QUITE SMALL BETWEEN THE VARIOUS MODELS...SO
CONFIDENCE IN THE MONDAY FORECAST IS FAIRLY HIGH. BY 12Z...THE FRONT
WILL BE CLOSE TO CLEARING THE CWA...SO ANY THREAT FOR THUNDER WILL
BE LIMITED TO THE FIRST FEW HOURS AFTER DAYBREAK IN THE FAR
SOUTHEAST CORNER. TEMPERATURES WILL FALL THROUGH THE DAY...THANKS TO
THE COLD ADVECTION BEHIND THE FRONT...THOUGH TEMPS IN THE NORTHWEST
MAY END UP STEADY BY AFTERNOON (BEFORE THE TYPICAL DIURNAL
TEMPERATURE DROPS BEGIN).
THE FORECAST COMPLICATION FOR THIS WEATHER SYSTEM REMAINS WITH THE
BACK SIDE SHORTWAVE ON MONDAY NIGHT INTO TUESDAY. THE MID LEVEL
TROUGH THAT WILL FOLLOW THE COLD FRONT (AND ITS ATTACHED SURFACE LOW
MOVING THROUGH THE LOWER GREAT LAKES) HAS BEEN MODELED WITH A FEW
SUBTLE DIFFERENCES...PRESENTING SOME CHALLENGES IN THE PRECIPITATION
FORECAST ON THE BACK SIDE OF THE FRONT. THIS SECONDARY TROUGH AXIS
(AS OPPOSED TO THE ONE DRIVING THE SURFACE LOW) HAS CONSISTENTLY
BEEN DEPICTED WITH A GREATER SHARPNESS ON THE ECMWF (HIGHER
AMPLITUDE AND SHORTER WAVELENGTH). THE GFS DEPICTION IS MUCH
BROADER...AND DOES NOT ALLOW FOR ADDITIONAL SURFACE LOW PRESSURE
DEVELOPMENT OVER THE SOUTHERN APPALACHIANS LIKE THE ECMWF.
TEMPERATURES MONDAY NIGHT ARE CERTAINLY COLD ENOUGH TO SUPPORT
SNOW...SO IF THE ECMWF SOLUTION WERE TO VERIFY...SOME LIGHT
ACCUMULATIONS WOULD BE POSSIBLE.
THE LONGWAVE PATTERN WILL FLIP FROM TROUGH TO RIDGE OVER THE EASTERN
CONUS BY THE MIDDLE OF THE WEEK. THE LARGE SCALE PATTERN HAS BEEN
STABLE IN THE VARIOUS SOLUTIONS...AND THOUGH THE GFSE MEMBERS SHOW
SOME SPREAD IN THE NUMBERS...THE PATTERN IS IDENTICAL IN ALMOST ALL
CASES. THIS LEADS TO INCREASING CONFIDENCE IN DRY WEATHER WITH
SURFACE HIGH PRESSURE NOSING IN FROM THE SOUTH...AND BECOMING FIRMLY
ESTABLISHED OVER THE EASTERN CONUS BY THURSDAY. THIS WILL ALLOW FOR
SOUTHWESTERLY FLOW TO INCREASE TEMPERATURES OVER THE OHIO
VALLEY...GOING ABOVE NORMAL BY THE END OF THE WEEK.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
BROAD SCALE LIFT AHEAD A STALLED CDFNT CONTINUES TO PRODUCE A
LARGE AREA OF RAIN AND IFR CLOUDS OVER THE TAFS. LATEST RADAR LOOP
IS SHOWING A BREAK FROM THE STEADIER RAINS WORKING NE FROM CENTRAL
KY. MIGHT SEE CIGS RISE TO MVFR OVER THE NEXT FEW HOURS AS THIS
AREA WORKS INTO CVG/LUK.
OVERNIGHT A SFC WAVE WORKS NE ALONG THE FRONT. MODELS ARE USING
THIS AS MEANS TO KICK THE PCPN EWD. THE NAM AND RAP ARE THE MOST
AGGRESSIVE WITH THE DRYING BEFORE 12Z...WHILE THE OTHER MODELS LINGER
PCPN CHANCE THRU 18Z. WENT WITH A BLEND OF THE SOLUTIONS...BY
BACKING OFF ON THE PREVAILING PCPN AFT 00Z...BUT KEPT A VCSH.
AM AFRAID WITH THE PCPN CHANCE LOWERING OVERNIGHT THAT THE DENSE
FOG THAT AFFECTED MANY OF THE TAFS THIS MORNING WILL RETURN.
BROUGHT LIFR VSBYS AND CIGS BACK INTO THE NRN TAFS AROUND 06Z.
AS SFC WAVE GOES BY AROUND 12Z SATURDAY...WINDS PICK UP AND TURN
TO A WESTERLY DIRECTION. THIS SHOULD HELP DISSIPATE THE DENSE FOG
DURING SATURDAY MORNING.
OUTLOOK...MVFR/IFR CIGS AND VSBYS POSSIBLE SATURDAY NIGHT INTO
MONDAY. A THUNDERSTORM IS POSSIBLE LATE SUNDAY AFTERNOON INTO
SUNDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...HATZOS
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
124 PM EST FRI DEC 7 2012
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN DRAPED ACROSS THE OHIO VALLEY
THROUGH THE WEEKEND. MOIST SOUTHWESTERLY FLOW WILL INTERACT WITH THE
BOUNDARY TO PRODUCE WIDESPREAD PRECIPITATION ACROSS THE REGION. A
COLD FRONT WILL PUSH EAST THROUGH THE AREA ON MONDAY...RESULTING
IN A DECREASING CHANCE OF PRECIPITATION AND COLDER TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AREAS OF DENSE FOG CONTINUE TO LINGER ACROSS SECTIONS OF THE FA.
THE LATEST ROUND OF OBSERVATIONS SHOWED SOME
IMPROVEMENTS...ESPECIALLY IN WEST CENTRAL OHIO OVER TO CENTRAL
OHIO. ACROSS THE WHITEWATER AND MIAMI VALLEYS THERE WERE STILL
NUMEROUS 1/4 MILE OBS. HOWEVER THE TREND LOOKS LIKE THINGS ARE
BEGINNING TO IMPROVE...SO ALLOWED THE DENSE FOG ADVISORY TO EXPIRE
AND COVERED THE FOG WITH A SPECIAL WEATHER STATEMENT.
THE STEADIER RAINS HAVE BEEN CONFINED TO NRN KY AND SE INDIANA
INTO SRN OH. MODELS ARE INDICATING THAT THE PCPN SHOULD INCREASE IN
COVERAGE AS THE DAY PROGRESSES AND THE LATEST RADAR LOOP IS
SHOWING SOME SIGNS OF THAT. LEFT OVERALL POPS THE SAME...100
ACROSS THE S AND 80 TO 90 IN THE NW.
DROPPED TEMPS A COUPLE OF DEGREES TODAY BASED ON CURRENT
TEMPERATURES AND LATEST TEMPERATURE GUIDANCE. WENT WITH HIGHS IN
THE UPPER 40S N AND MID 50S IN NRN KY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
A WAVE OF LOW PRESSURE WILL RIDE EASTWARD ALONG THE BOUNDARY THIS
EVENING...KEEPING WIDESPREAD PCPN GOING THROUGH MUCH OF TONIGHT.
AS THE WAVE PUSHES OFF TO THE EAST LATER TONIGHT THOUGH...WE COULD
BEGIN TO SEE PCPN TAPER OFF FROM THE NORTHWEST LATE TONIGHT INTO
SATURDAY MORNING AS THE BETTER LOW LEVEL JET DYNAMICS ALSO SHIFT
OFF TO THE EAST. WILL THEREFORE TRIM POPS BACK A BIT FOR
SATURDAY...PARTICULARLY ACROSS THE NORTH. HOWEVER...THE BOUNDARY
WILL REMAIN DRAPED ALONG THE OHIO RIVER SO WILL HANG ON TO SOME
BETTER POPS THERE. MODELS HAVE BACKED OFF SOME WITH THE ELEVATED
CAPES...ALTHOUGH 850 MB LI/S DO APPROACH ZERO UP TO ABOUT THE OHIO
RIVER. WILL THEREFORE TRIM BACK THUNDER CHANCES TO JUST OUR FAR
SOUTH...PRIMARILY FOR SATURDAY AFTERNOON.
A STRONGER SURFACE LOW WILL WORK EAST ALONG THE BOUNDARY SATURDAY
NIGHT INTO SUNDAY...BRINGING YET ANOTHER WAVE OF PCPN TO OUR
REGION. SOME MODEL DIFFERENCES DO EXIST ON THE EXACT TRACK OF THIS
LOW...BUT THE GENERAL TREND IS FOR IT TO LIFT UP ACROSS
NORTHWESTERN PORTIONS OF OUR FA. THIS WILL HELP AT LEAST THE
SOUTHEASTERN PORTION OF OUR FA TO GET INTO THE WARM SECTOR
THROUGH THE DAY ON SUNDAY. THIS WILL ALLOW FOR SOME SLIGHTLY
WARMER TEMPERATURES AND THE POSSIBILITY OF AN ISOLATED
THUNDERSTORM AS WE MAY DESTABILIZE A BIT. AS THE LOW LIFTS OFF TO
THE NORTHEAST...IT WILL HELP PULL A COLD FRONT DOWN ACROSS OUR
AREA LATE SUNDAY NIGHT INTO MONDAY. PCPN CHANCES WILL BEGIN TO
DECREASE FROM THE NORTHWEST THROUGH THE DAY ON MONDAY AS DRIER AIR
PUSHES IN BEHIND THE FRONT. THIS WILL ALSO BE ACCOMPANIED BY SOME
CAA...BUT LOW LEVELS SHOULD REMAIN WARM ENOUGH TO KEEP ANY PCPN
RAIN THROUGH THE DAY ON MONDAY.
IT LOOKS LIKE THE HEAVIEST PCPN THROUGH THE WEEKEND WILL SET UP
ACROSS THE SOUTHEASTERN HALF OF OUR FA. PWS WILL BE RUNNING 200 TO
250 PERCENT OF NORMAL AT TIMES THROUGH SUNDAY AND AS A
RESULT...SOME LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. BY THE TIME
THE RAIN ENDS...WE MAY VERY WELL END UP WITH A SWATH OF 3 TO 4 INCHES OF
RAIN SOMEWHERE ACROSS OUR SOUTHEAST. GIVEN THE RECENT DRY
CONDITIONS THOUGH...12 HOUR FFG IS MAINLY RUNNING IN THE 2.5 TO 4
INCH RANGE WITH 24 HR FFG EVEN HIGHER. THUS...UNLESS PCPN BECOMES
MORE CONVECTIVE THAN CURRENT THINKING...BELIEVE OVERALL FLOOD
THREAT WILL REMAIN ON THE LOW END.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
THE MID LEVEL TROUGH THAT WILL FOLLOW THE FRONT (AND ITS ATTACHED
SURFACE LOW MOVING THROUGH THE GREAT LAKES) HAS BEEN MODELED WITH
A FEW SUBTLE DIFFERENCES...PRESENTING SOME CHALLENGES IN THE
PRECIPITATION FORECAST ON THE BACK SIDE OF THE FRONT. THOUGH ONE
AXIS CAN BE DEPICTED NEAR AND ASSOCIATED WITH THE PRIMARY SURFACE
LOW...THE 12Z ECMWF DEPICTS A SHARPER AXIS WITH THE BASE OF THE
TROUGH BEHIND THE COLD FRONT. THIS LEADS TO THE GENESIS OF A
SURFACE LOW OVER THE TENNESSEE VALLEY AND SOUTHERN
APPALACHIANS...WHICH HAS ENOUGH OF AN IMPACT OVER OUR REGION TO
SPREAD ADDITIONAL PRECIPITATION IN BEHIND THE FRONT. THIS FEATURE
IS ALSO SHOWN ON THE 12Z GFS...THOUGH IT IS NOT AS AMPLIFIED. IF
THIS OCCURS...THE CHANCES OF SNOW WILL INCREASE...AS TEMPERATURES
MONDAY NIGHT ARE CERTAINLY COLD ENOUGH TO SUPPORT SNOW AS THE
PRIMARY (OR ONLY) PRECIPITATION TYPE.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
BROAD SCALE LIFT AHEAD A STALLED CDFNT CONTINUES TO PRODUCE A
LARGE AREA OF RAIN AND IFR CLOUDS OVER THE TAFS. LATEST RADAR LOOP
IS SHOWING A BREAK FROM THE STEADIER RAINS WORKING NE FROM CENTRAL
KY. MIGHT SEE CIGS RISE TO MVFR OVER THE NEXT FEW HOURS AS THIS
AREA WORKS INTO CVG/LUK.
OVERNIGHT A SFC WAVE WORKS NE ALONG THE FRONT. MODELS ARE USING
THIS AS MEANS TO KICK THE PCPN EWD. THE NAM AND RAP ARE THE MOST
AGGRESSIVE WITH THE DRYING BEFORE 12Z...WHILE THE OTHER MODELS LINGER
PCPN CHANCE THRU 18Z. WENT WITH A BLEND OF THE SOLUTIONS...BY
BACKING OFF ON THE PREVAILING PCPN AFT 00Z...BUT KEPT A VCSH.
AM AFRAID WITH THE PCPN CHANCE LOWERING OVERNIGHT THAT THE DENSE
FOG THAT AFFECTED MANY OF THE TAFS THIS MORNING WILL RETURN.
BROUGHT LIFR VSBYS AND CIGS BACK INTO THE NRN TAFS AROUND 06Z.
AS SFC WAVE GOES BY AROUND 12Z SATURDAY...WINDS PICK UP AND TURN
TO A WESTERLY DIRECTION. THIS SHOULD HELP DISSIPATE THE DENSE FOG
DURING SATURDAY MORNING.
OUTLOOK...MVFR/IFR CIGS AND VSBYS POSSIBLE SATURDAY NIGHT INTO
MONDAY. A THUNDERSTORM IS POSSIBLE LATE SUNDAY AFTERNOON INTO
SUNDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...SITES
SHORT TERM...JGL
LONG TERM...HATZOS
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1247 PM CST FRI DEC 7 2012
.UPDATE...
LATEST SATELLITE AND SURFACE DATA INDICATE CONDITIONS ARE
IMPROVING ACROSS WEST CENTRAL TEXAS. THE STRATUS HAS ALL BUT
DISSIPATED...WITH ONLY REMNANTS REMAINING OVER THE HEARTLAND.
ALOFT...SATELLITE DATA INDICATE HIGHER CLOUD STREAKS CONTINUE
ACROSS MUCH OF WEST TEXAS. AT THE SURFACE ACROSS WEST CENTRAL
TEXAS...TEMPERATURES AND DEWPOINT HAVE INCREASED SLIGHTLY FASTER
THAN WE WERE THINKING. PLUS...SURFACE WINDS ACROSS WEST CENTRAL
TEXAS ARE STILL VERY LIGHT AND VARIABLE. BASED ON SURFACE DEWPOINT
ANALYSIS...THE OLD FRONTAL BOUNDARY LIKELY LIES SOMEWHERE NEAR A
COLEMAN TO ROBERT LEE LINE. THE RUC INDICATES SURFACE WINDS WILL
REMAIN VERY LIGHT AND VARIABLE FOR THE REMAINDER OF TODAY. I MADE
SOME ADJUSTMENTS TO A FEW GRID ELEMENTS FOR THE REMAINDER OF TODAY
TO BRING THEM IN LINE WITH TRENDS OVER THE LAST COUPLE HOURS. I
BELIEVE AFTERNOON HIGHS STILL LOOK REASONABLE. SO...I DID NOT
CHANGE THAT GRID. THE LATEST ZONE...POINT FORECAST MATRIX...AND
TABULAR STATE FORECAST PRODUCTS REFLECT MY GRID ADJUSTMENTS.
HUBER
&&
.PREV DISCUSSION... /ISSUED 1202 PM CST FRI DEC 7 2012/
DISCUSSION...
LOOK FOR STRATUS TO BRING MVFR CEILINGS BACK TO SOME AREAS OF WEST
CENTRAL TEXAS EARLY TOMORROW MORNING. AVIATION BELOW HAS DETAILS.
AVIATION...
EXPECT VFR CONDITIONS THIS AFTERNOON AND TONIGHT ACROSS WEST CENTRAL
TEXAS...BEFORE RETURNING STRATUS BRINGS MVFR CEILINGS BACK INTO
SOME OF WEST CENTRAL TEXAS EARLY TOMORROW MORNING. A STALLED
FRONTAL BOUNDARY IS PRODUCING VERY LIGHT AND VARIABLE SURFACE
WINDS ACROSS WEST CENTRAL TEXAS THIS MORNING. THE NAM AND RUC
SURFACE DATA INDICATE THIS SURFACE BOUNDARY WILL REMAIN OVER WEST
CENTRAL TEXAS FOR MOST OF THE NEXT 24 HOURS. THUS...PLAN FOR
MAINLY LIGHT AND VARIABLE SURFACE WINDS FOR THE NEXT 24 HOURS.
AROUND SUNRISE TOMORROW MORNING...WATCH FOR STRATUS TO MOVE INTO
THE SAME AREAS AS THIS MORNING. NEITHER THE NAM-BASED OR THE GFS-
BASED AVIATION GUIDANCE INDICATE STRATUS FOR THE SAN ANGELO
TERMINAL. HOWEVER...I DECIDED TO INCLUDE MVFR CEILINGS FOR THE SAN
ANGELO TERMINAL BEGINNING AT 13Z BASED MAINLY ON PERSISTENCE. FOR
OUR OTHER THREE SOUTHERN TERMINALS...THE MODELS DO INDICATE MVFR
CEILINGS. SO...MY CONFIDENCE IS MUCH HIGHER FOR STRATUS RETURN TO
THOSE THREE.
HUBER
PREV DISCUSSION... /ISSUED 533 AM CST FRI DEC 7 2012/
UPDATE...
ANALYSIS OF RECENT VAD WINDS AND SODAR DATA INDICATES THAT THE
WEDGE OF COOLER AIR NORTH OF THE FRONTAL BOUNDARY IS ONLY ABOUT
700 FT DEEP AS FAR NORTH AS SAN ANGELO. WITH THE BOUNDARY LOSING
MOMENTUM AND STALLING...IT SHOULD NOT TAKE LONG TO MIX OUT THE
COOLER AIR ACROSS THE SOUTHERN ZONES. LOW CLOUDS ARE JUST MAKING
THEIR WAY INTO MASON COUNTY BUT DEWPOINTS ARE IN THE LOW/MID 60S
JUST SOUTH OF I-10 /KECU AND KERV/. AS THE COLD DOME ERODES...
LOW LEVEL MOISTURE WILL INCREASE AND MAY RESULT IN THE DEVELOPMENT
OF A STRATO CU DECK ACROSS THE I-10 CORRIDOR AND INTO THE
HEARTLAND COUNTIES. FARTHER NORTH...THIS AIRMASS IS AT LEAST 1000
FT DEEPER AND WILL BE MORE DIFFICULT TO MIX OUT TODAY.
JOHNSON
AVIATION...
GENERALLY VFR CONDITIONS ARE ANTICIPATED THROUGH THE TAF PERIOD.
THE PRIMARY EXCEPTION IS THE POTENTIAL FOR LOW CIGS FOR A FEW
HOURS THIS MORNING /AND AGAIN LATE TONIGHT/ AT KJCT. HIGH CLOUDS
ARE MASKING THE STRATUS ON THE SATELLITE IMAGERY BUT IT DOES
APPEAR THAT THE LOW CLOUDS HAVE MADE IT INTO MASON COUNTY.
OTHERWISE...EXPECT MAINLY BROKEN HIGH CLOUDS THIS MORNING BECOMING
SCATTERED DURING THE DAY. WINDS WILL REMAIN LESS THAN 10 KTS WITH
THE QUASI STATIONARY BOUNDARY IN THE VICINITY. NORTHWEST WINDS
WILL CONTINUE AT KABI WITH SOUTH WINDS EVENTUALLY DEVELOPING AT
THE OTHER FORECAST TERMINALS.
JOHNSON
PREV DISCUSSION... /ISSUED 340 AM CST FRI DEC 7 2012/
SHORT TERM...
WE CONTINUE TO SEE STRONG QUASI ZONAL FLOW ALOFT ACROSS THE
CENTRAL CONUS DOWNSTREAM OF AN OPEN...POSITIVELY TITLED TROUGH
THAT IS TRAVERSING THE FOUR CORNERS. A WEAK COLD FRONT HAS MOVED
INTO WEST CENTRAL TX AS FAR SOUTH OF THE I-10 CORRIDOR BUT HAS
BECOME RATHER DIFFUSE AT THIS TIME GIVEN THE TYPICAL LIGHT
NOCTURNAL WINDS OVER THE SOUTHERN ZONES. THE LOW STRATUS THAT IS
DEVELOPING OVER THE HILL COUNTRY IS EXPECTED TO MOVE NORTH INTO
THE SOUTHEAST CORNER OF THE CWA AND MAY OVERRUN THE SHALLOW
FRONTAL ZONE THROUGH THE EARLY MORNING HOURS. HOWEVER...THESE
CLOUDS ARE FORECAST TO ERODE BY MID/LATE MORNING. A 100 KT JET
STREAK CURRENTLY EXTENDS FROM SOUTHERN NM TO MO...WITH WEAK
SURFACE CYCLOGENESIS UNDERWAY IN THE RIGHT ENTRANCE REGION OVER
SOUTHWEST TX. THE SOUTHERLY FLOW ON THE EASTERN FLANK SHOULD PUSH
THIS BOUNDARY BACK TO THE NORTH TODAY...STALLING SOMEWHERE IN THE
VICINITY OF A STERLING CITY TO BROWNWOOD LINE. TEMPS SOUTH OF THE
FRONT ARE EXPECTED TO WARM INTO THE LOW TO MID 70S WHILE MID/UPPER
60S AND ANTICIPATED NORTH OF THE BOUNDARY. WINDS WILL REMAIN LESS
THAN 10 MPH THROUGHOUT THE DAY AREAWIDE. THE HIGH CLOUDS
ASSOCIATED WITH THE AFOREMENTIONED SUBTROPIC JET WILL ERODE DURING
THE DAY...RESULTING IN PARTLY CLOUDY SKIES BY THE AFTERNOON HOURS.
AS THE SUN SETS AND THE BOUNDARY LAYER COOLS...THIS QUASI
STATIONARY FRONT MAY TRY TO SLIDE SOUTH BACK INTO THE CONCHO
VALLEY. IT REALLY SHOULD HAVE LITTLE IMPACT OTHER THAN SERVING TO
LOWER DEWPOINTS. MIN TEMPS WILL REMAIN UNSEASONABLY MILD...RANGING
FROM THE LOWER 40S TO THE NEAR 50 DEGREES. THE MODELS CONTINUE TO
BRING DEWPOINTS BACK INTO THE LOWER 50S ALONG THE I-10 CORRIDOR
BUT THEY HAVE BEEN QUITE POOR AS OF LATE...EVEN WITH MODEL
INITIALIZATIONS. ANY STRATUS AND/OR FOG SHOULD BE CONFINED TO THE
SOUTHEAST QUADRANT OF THE CWA TONIGHT WITH MOSTLY CLEAR SKIES
ELSEWHERE.
JOHNSON
LONG TERM...
BY SATURDAY MORNING THE FLOW ALOFT OVER THE FORECAST AREA WILL BE
ZONAL...BEGINNING TO BACK TO THE SOUTHWEST AHEAD OF AN UPPER
TROUGH DIGGING SOUTH OVER THE SOUTHWESTERN STATES. WILL HAVE
WARMING TEMPERATURES SATURDAY WITH AFTERNOON HIGHS WELL ABOVE
SEASONAL NORMS IN THE LOWER 70S TO THE LOWER 80S UNDER MOSTLY
SUNNY SKIES. AS THE UPPER TROUGH MOVES EAST ACROSS THE CWA SUNDAY
IT WILL PUSH A STRONG COLD FRONT SOUTH THROUGH THE FORECAST AREA
SUNDAY...EXITING OUR SOUTHERN TIER OF COUNTIES SUNDAY EVENING.
MODELS ARE SHOWING SATURATED SOUNDINGS TO AROUND 500MB AFTER
MIDNIGHT ON SUNDAY AND INTO MONDAY MORNING OVER THE BIG COUNTRY.
HAVE INCLUDED A SLIGHT CHANCE OF LIGHT SNOW OVER THE BIG COUNTRY
AFTER MIDNIGHT...ENDING AROUND MID-MORNING ON MONDAY. GIVEN WARM
GROUND CONDITIONS AHEAD OF THE FRONTAL PASSAGE...NOT EXPECTING ANY
SNOW ACCUMULATION WITH THIS SYSTEM. HOWEVER...WILL SEE THIS
SEASONS COLDEST TEMPERATURES. MONDAY MORNING TEMPERATURES WILL
RANGE FROM THE UPPER 20S TO AROUND 30 DEGREES WITH THE COLDEST
MORNING TEMPERATURES ON TUESDAY...WITH LOWS IN THE LOWER 20S
ACROSS THE ENTIRE FORECAST AREA. AFTERNOON HIGHS ON MONDAY WILL
ONLY BE IN THE 40S WITH TUESDAY AFTERNOON HIGHS IN THE 50S.
FOR THE REMAINDER OF THE WEEK WE WILL HAVE SEASONAL AFTERNOON
HIGHS IN THE LOWER 60S AND CLOSE TO SEASONAL MORNING LOWS
GENERALLY IN THE MID 30S. NO ADDITIONAL PRECIPITATION IS
EXPECTED THROUGH THE END OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 42 75 50 59 29 / 0 0 0 10 10
SAN ANGELO 43 81 51 67 31 / 0 0 0 5 10
JUNCTION 48 82 52 73 32 / 0 5 0 10 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
HUBER