Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/09/12
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 COLUMBIA SC
1018 PM EST SAT DEC 8 2012
.SYNOPSIS...
WEAK SURFACE HIGH PRESSURE WILL REMAIN OVER THE REGION TONIGHT AND
SUNDAY. A COLD FRONT WILL SLOWLY COME THROUGH MONDAY NIGHT AND
TUESDAY...STALLING JUST TO OUR SOUTH THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
WEAK SURFACE HIGH PRESSURE THAT HAS BEEN OVER THE REGION IS
BEGINNING TO GRADUALLY PUSH OFFSHORE. MODEL TIME SECTIONS INDICATE
A LIGHT SOUTH/SOUTH-SOUTHWEST FLOW OVERNIGHT...WITH INCREASING LOW
LEVEL MOISTURE TOWARD SUNDAY MORNING. SATELLITE LOOP/OBS SHOW SOME
LOW CLOUDS ACROSS THE UPSTATE/GA WITH CIRRUS STREAMING OVERHEAD.
AMOUNT OF CLOUD COVER STILL A BIT UNCERTAIN OVERNIGHT INTO
SUNDAY...BUT EXPECT SOME OF THE LOW/MID CLOUDS ACROSS GA TO
EVENTUALLY PUSH NORTH/NORTHEAST TO THE CSRA AND EVENTUALLY INTO
THE MIDLANDS. AS FOR FOG POTENTIAL...WITH SOME AREAS MOSTLY
CLEAR...EXPECT SOME PATCHY/AREAS OF FOG TO FORM AFTER MIDNIGHT AND
LINGER THROUGH THE EARLY MORNING HOURS ON SUNDAY.
&&
.SHORT TERM /SUNDAY NIGHT/...
WEAK HIGH PRESSURE TO SHIFT TO THE EAST SOME SUNDAY AHEAD OF AN
APPROACHING FRONT. A SW LOW TO MID LEVEL FLOW TO PROVIDE WARM
TEMPS. MODELS OUTPUT SUGGESTS A WEAK UPPER DISTURBANCE...ALONG
WITH SOME LOW LEVEL MOISTURE FLUX AND WEAK INSTABILITY MAY PRODUCE
A FEW SHOWERS. CONFIDENCE LIMITED...BUT USED A MOS BLEND TO
INDICATE A SLIGHT CHANCE OF A SHOWER OVER PORTIONS OF THE FA.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
MODELS CONTINUE TREND OF SLOWING DOWN THE APPROACH OF THE NEXT
FRONTAL BOUNDARY...NOW PROGGED TO SLOWLY COME THROUGH MONDAY
NIGHT AND TUESDAY. MAINTAINED MENTION OF CHANCE SHOWERS...WITH
SLIGHT CHANCE THUNDER...LATE MONDAY INTO TUE. WITH A SW FLOW
ALOFT...PARALLEL TO THE FRONT...THE FRONT WILL BE SLOW TO MOVE
THROUGH...AND GFS/ECMWF SUGGEST IT WILL STALL JUST SOUTH OF OUR
REGION. CONTINUED TO ACCEPT HPC GUIDANCE...WHICH PREFERS ECMWF
SOLUTION. ECMWF INDICATES ANOTHER WAVE TO MOVE ALONG THE FRONT
LATE WED AND THU.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
DECREASING MID LEVEL CLOUDS THIS EVENING. WATER VAPOR INDICATING ANOTHER
SHORT WAVE TO CROSS THE REGION OVERNIGHT...KEEPING HIGH CLOUDS IN
THE AREA TO INHIBIT FOG DEVELOPMENT. AT THE SAME TIME FOG AND
STRATUS OVER NORTHERN FL AND SOUTHERN GA MAKING SOME PROGRESS
NORTHWARD. BOTH NAM AND RAP MODELS BRING FOG/STRATUS INTO THE
SAVANNAH RIVER AREA 06Z-09Z AND CONTINUES TO SPREAD LIFR CONDITIONS
ACROSS ALL TAF SITES. CONFIDENCE IS IMPROVING FOR IFR OR LOWER
CONDITIONS OVERSPREADING THE TAF SITES OVERNIGHT INTO SUNDAY
MORNING. SHOULD SEE IMPROVING CONDITIONS TO VFR 16Z-20Z.
EXTENDED AVIATION OUTLOOK...HIGH LOW-LEVEL MOISTURE IS FORECAST TO
RESULT IN WIDESPREAD IFR/LIFR CONDITIONS SUNDAY NIGHT INTO LATE
MONDAY MORNING. FURTHER RESTRICTIONS POSSIBLE IN SHOWERS ASSOCIATED
WITH A COLD FRONT MONDAY INTO WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
931 PM EST SAT DEC 8 2012
.SYNOPSIS...
WEAK SURFACE HIGH PRESSURE WILL REMAIN OVER THE REGION TONIGHT AND
SUNDAY. A COLD FRONT WILL SLOWLY COME THROUGH MONDAY NIGHT AND
TUESDAY...STALLING JUST TO OUR SOUTH THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
WEAK SURFACE HIGH PRESSURE THAT HAS BEEN OVER THE REGION IS
BEGINNING TO GRADUALLY PUSH OFFSHORE. MODEL TIME SECTIONS INDICATE
A LIGHT SOUTH/SOUTH-SOUTHWEST FLOW OVERNIGHT...WITH INCREASING LOW
LEVEL MOISTURE TOWARD SUNDAY MORNING. SATELLITE LOOP/OBS SHOW SOME
LOW CLOUDS ACROSS THE UPSTATE/GA WITH CIRRUS STREAMING OVERHEAD.
AMOUNT OF CLOUD COVER STILL A BIT UNCERTAIN OVERNIGHT INTO
SUNDAY...BUT EXPECT SOME OF THE LOW/MID CLOUDS ACROSS GA TO
EVENTUALLY PUSH NORTH/NORTHEAST TO THE CSRA AND EVENTUALLY INTO
THE MIDLANDS. AS FOR FOG POTENTIAL...WITH SOME AREAS MOSTLY
CLEAR...EXPECT SOME PATCHY/AREAS OF FOG TO FORM AFTER MIDNIGHT AND
LINGER THROUGH THE EARLY MORNING HOURS ON SUNDAY.
&&
.SHORT TERM /SUNDAY NIGHT/...
WEAK HIGH PRESSURE TO SHIFT TO THE EAST SOME SUNDAY AHEAD OF AN
APPROACHING FRONT. A SW LOW TO MID LEVEL FLOW TO PROVIDE WARM
TEMPS. MODELS OUTPUT SUGGESTS A WEAK UPPER DISTURBANCE...ALONG
WITH SOME LOW LEVEL MOISTURE FLUX AND WEAK INSTABILITY MAY PRODUCE
A FEW SHOWERS. CONFIDENCE LIMITED...BUT USED A MOS BLEND TO
INDICATE A SLIGHT CHANCE OF A SHOWER OVER PORTIONS OF THE FA.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
MODELS CONTINUE TREND OF SLOWING DOWN THE APPROACH OF THE NEXT
FRONTAL BOUNDARY...NOW PROGGED TO SLOWLY COME THROUGH MONDAY
NIGHT AND TUESDAY. MAINTAINED MENTION OF CHANCE SHOWERS...WITH
SLIGHT CHANCE THUNDER...LATE MONDAY INTO TUE. WITH A SW FLOW
ALOFT...PARALLEL TO THE FRONT...THE FRONT WILL BE SLOW TO MOVE
THROUGH...AND GFS/ECMWF SUGGEST IT WILL STALL JUST SOUTH OF OUR
REGION. CONTINUED TO ACCEPT HPC GUIDANCE...WHICH PREFERS ECMWF
SOLUTION. ECMWF INDICATES ANOTHER WAVE TO MOVE ALONG THE FRONT
LATE WED AND THU.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
PLENTY OF MID-LEVEL CLOUDS AFFECTING THE TAF SITES WITH LIGHT WINDS
THIS EVENING. WATER VAPOR APPEARS TO KEEP MID/UPPER LEVEL MOISTURE
ACROSS THE REGION THROUGH 06Z...PRECLUDING FOG DEVELOPMENT.
MAY SEE ENOUGH DRYING ALOFT FOR RADIATIONAL COOLING AFTER 06Z.
BOTH NAM AND RAP BUFKIT DEPICTS MORE STRATUS DEVELOPMENT THAN FOG
BETWEEN 06Z AND 09Z. HIGH CONFIDENCE THAT AT LEAST MVFR VISIBILITY
CONDITIONS WILL DEVELOP AFTER 06Z...WITH IFR OR LIFR VISIBILITY AND
CEILINGS FROM THE 10Z TO 14Z PERIOD AT ALL TERMINAL LOCATIONS.
IMPROVING CONDITIONS TO VFR 15Z-17Z.
EXTENDED AVIATION OUTLOOK...HIGH LOW-LEVEL MOISTURE MAY RESULT IN
WIDESPREAD IFR CONDITIONS MAINLY DURING THE EARLY MORNING MONDAY.
FURTHER RESTRICTIONS POSSIBLE IN SHOWERS ASSOCIATED WITH A COLD FRONT
MONDAY INTO WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
77
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
648 PM EST SAT DEC 8 2012
.SYNOPSIS...
WEAK SURFACE HIGH PRESSURE WILL REMAIN OVER THE REGION TONIGHT AND
SUNDAY. A COLD FRONT WILL SLOWLY COME THROUGH MONDAY NIGHT AND
TUESDAY...STALLING JUST TO OUR SOUTH THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
WEAK SURFACE HIGH PRESSURE CURRENTLY OVER THE REGION. PLENTIFUL
LOW LEVEL MOISTURE AND A WEAK UPPER DISTURBANCE PROVIDING SCT TO
BKN CLOUDS. STILL UNCERTAIN ABOUT AMOUNT OF CLOUD COVER
OVERNIGHT...BUT AS MENTIONED PLENTY OF LOW LEVEL MOISTURE ALONG
WITH SOME WEAK ISENTROPIC LIFT OVERNIGHT. ANY CLEARING WOULD
PROVIDE POTENTIAL FOR FOG DEVELOPMENT. SO EXPECT A COMBINATION OF
MOSTLY CLOUDY SKIES AND PATCHY/AREAS OF FOG AFTER MIDNIGHT THROUGH
SUNDAY MORNING.
&&
.SHORT TERM /SUNDAY NIGHT/...
WEAK HIGH PRESSURE TO SHIFT TO THE EAST SOME SUNDAY AHEAD OF AN
APPROACHING FRONT. A SW LOW TO MID LEVEL FLOW TO PROVIDE WARM
TEMPS. MODELS OUTPUT SUGGESTS A WEAK UPPER DISTURBANCE...ALONG
WITH SOME LOW LEVEL MOISTURE FLUX AND WEAK INSTABILITY MAY PRODUCE
A FEW SHOWERS. CONFIDENCE LIMITED...BUT USED A MOS BLEND TO
INDICATE A SLIGHT CHANCE OF A SHOWER OVER PORTIONS OF THE FA.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
MODELS CONTINUE TREND OF SLOWING DOWN THE APPROACH OF THE NEXT
FRONTAL BOUNDARY...NOW PROGGED TO SLOWLY COME THROUGH MONDAY
NIGHT AND TUESDAY. MAINTAINED MENTION OF CHANCE SHOWERS...WITH
SLIGHT CHANCE THUNDER...LATE MONDAY INTO TUE. WITH A SW FLOW
ALOFT...PARALLEL TO THE FRONT...THE FRONT WILL BE SLOW TO MOVE
THROUGH...AND GFS/ECMWF SUGGEST IT WILL STALL JUST SOUTH OF OUR
REGION. CONTINUED TO ACCEPT HPC GUIDANCE...WHICH PREFERS ECMWF
SOLUTION. ECMWF INDICATES ANOTHER WAVE TO MOVE ALONG THE FRONT
LATE WED AND THU.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
PLENTY OF MID-LEVEL CLOUDS AFFECTING THE TAF SITES WITH LIGHT WINDS
THIS EVENING. WATER VAPOR APPEARS TO KEEP MID/UPPER LEVEL MOISTURE
ACROSS THE REGION THROUGH 06Z...PRECLUDING FOG DEVELOPMENT.
MAY SEE ENOUGH DRYING ALOFT FOR RADIATIONAL COOLING AFTER 06Z.
BOTH NAM AND RAP BUFKIT DEPICTS MORE STRATUS DEVELOPMENT THAN FOG
BETWEEN 06Z AND 09Z. HIGH CONFIDENCE THAT AT LEAST MVFR VISIBILITY
CONDITIONS WILL DEVELOP AFTER 06Z...WITH IFR OR LIFR VISIBILITY AND
CEILINGS FROM THE 10Z TO 14Z PERIOD AT ALL TERMINAL LOCATIONS.
IMPROVING CONDITIONS TO VFR 15Z-17Z.
EXTENDED AVIATION OUTLOOK...HIGH LOW-LEVEL MOISTURE MAY RESULT IN
WIDESPREAD IFR CONDITIONS MAINLY DURING THE EARLY MORNING MONDAY.
FURTHER RESTRICTIONS POSSIBLE IN SHOWERS ASSOCIATED WITH A COLD FRONT
MONDAY INTO WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
904 PM CST SAT DEC 8 2012
.UPDATE...
NO BIG CHANGES WITH EVENING UPDATE BUT HAVE NUDGED UP THE SNOW
AMOUNTS NE IN THE MASON CITY AND WATERLOO AREAS. SMALL AREA OF
PRECIP THAT MOVED THROUGH CENTRAL IA RECENTLY WAS MAINLY RAIN AT THE
AIRPORT...BUT PRIMARILY SNOW JUST TO THE NORTH HERE AT THE
OFFICE...AT BOONE AND AMES. MAINLY MELTED BUT JUST STUCK A LITTLE
IN SOME AREAS. EXPECT THIS TO CONTINUE AS IT WORKS NE LATER TONIGHT
AS 02Z RAP 2.5KM LAYER MAX WET BULB TEMP CHANGES LITTLE OVERNIGHT.
THIS SUGGESTS CURRENT SNOW AND RAIN/SNOW LINES ARE A TAD TOO FAR
NORTH AND HAVE SHIFTED THEM A BIT SOUTHWARD RESULTING IN A HALF INCH
OR MORE INCREASE IN SNOW AMOUNTS THERE. LATEST NAM...DEV HRRR AND
WRF RUNS ALL SUGGEST LOBE OF FORCING CURRENTLY PRODUCING PRECIP FROM
SW MN INTO IA WILL FURTHER SATURATE AND THEN PHASE WITH MATURING
SERN IA PRECIP WITH MORE WIDESPREAD COVERAGE OVER NERN IA TOWARD
DAYBREAK.
&&
.SHORT TERM /TONIGHT/...
BAND OF STRONG THETA-E ADVECTION IS MOVING INTO WESTERN IOWA THIS
AFTERNOON AND WILL CONTINUE TO MOVE ACROSS THE STATE THIS EVENING.
RADAR ECHOES HAVE BEEN INTENSIFYING WITH THIS MID LEVEL FORCING FROM
SOUTHWEST IOWA THROUGH SOUTHEAST SOUTH DAKOTA AND AT THIS
TIME...ONLY PRECIPITATION REPORTS ARE FROM THE NORTHERN EDGE WITH
CLOUD HEIGHTS REMAINING AOA 7KFT FARTHER SOUTH. EXPECT SOME LIGHT
PRECIPITATION TO FALL OVER THE NORTHWEST THIRD TO HALF THIS EVENING
ALONG THE INITIAL MOISTURE SURGE. SOME OF THIS PRECIPITATION COULD
BE LIGHT SNOW GIVEN WETBULB PROFILES AS FAR SOUTH AS HIGHWAY 30
THOUGH NO ACCUMULATIONS ARE EXPECTED THIS EVENING EXCEPT FOR
POSSIBLY THE FAR NORTH. A SECONDARY THETA-E SURGE WILL FOLLOW AFTER
MIDNIGHT. THIS WILL HELP KEEP LOW LEVEL TEMPERATURES ABOVE FREEZING
OVER THE CENTRAL AND SOUTH AND KEEP WETBULBS IN THE LOWEST
1500-2500FT 34F OR HIGHER. THIS LAYER WILL BE ENOUGH TO MELT ANY
SNOW THROUGH THIS REGION. COLDER PROFILES YET NORTH WHERE
PRECIPITATION WILL BE EXPANDING WITH THE ARRIVAL OF INCREASING
KINEMATICS WITH THE APPROACH OF THE UPPER LEVEL SHORT WAVE. THE
PRECIPITATION WILL BE ALL SNOW OVER THE NORTH. EXPECT SEASONAL TO
SLIGHTLY HIGHER SNOW RATIOS OVER THE NORTH OF 13-15 TO 1 AND COULD
HAVE ACCUMULATIONS BY 12Z OF 0.5 TO 1.5 INCHES ALONG AND NORTH OF A
DENISON TO FORT DODGE TO WAVERLY LINE. NON-DIURNAL TEMPERATURE
TRENDS OVERNIGHT WITH HIGHER DEWPOINTS MOVING INTO THE STATE.
.LONG TERM /SUNDAY THROUGH FRIDAY/...
THERE ARE TWO SYSTEMS TO FOCUS ON IN THE EXTENDED. THE FIRST IS THE
SYSTEM FROM TONIGHT THAT WILL BE QUICKLY PUSHING ACROSS THE CWA
DURING THE MORNING HOURS FOLLOWED BY STRONG COLD ADVECTION.
SOUNDINGS AT 12Z SHOW TEMPERATURES AT OR JUST ABOVE FREEZING ACROSS
THE FORECAST AREA. A COLD FRONT WILL SWEEP THE CWA THROUGH THE
MORNING AND SOUNDING LOCATIONS WEST OF I-35 DRY OUT BEHIND THE FRONT
WITH TEMPERATURES FALLING THROUGHOUT THE LATE MORNING AND THE REST
OF THE DAY. FORCING WEAKENS THROUGHOUT THE DAY BUT POCKETS OF
BETTER FORCING REMAIN ACROSS CENTRAL IOWA THROUGH MOST OF THE DAY.
THE PROBLEM IS THAT WE LOSE OUR DEEPER MOISTURE QUICKLY IN THE
MORNING. AS A RESULT...I AM NOT LOOKING FOR MUCH IN THE WAY OF
PRECIPITATION/SNOW ACCUMULATION OUT OF THIS SYSTEM. WE COULD SEE A
COUPLE OF INCHES ACROSS THE NORTH AT BEST WITH TRACE AMOUNTS
ELSEWHERE AS PRECIP TRANSITIONS TO SNOW BEFORE ENDING. THE SURFACE
LOW IS TOO FAR NORTH AND THE UPPER WAVE IS NOT DEEP ENOUGH TO DO
MUCH MORE THAN THAT. WINDS ON THE OTHER HAND MAY BE PROBLEMATIC
SUNDAY...ESPECIALLY COMBINED WITH THE COLD AIR MOVING IN. WIND
CHILLS WILL FALL INTO THE TEENS DURING THE AFTERNOON.
TUESDAY THROUGH THURSDAY...THERE WILL BE A LONG WAVE TROUGH PASSING
ACROSS THE REGION WITH A RIDGE BUILDING INTO THE WEST TUESDAY AND
SHIFTING ACROSS THE MIDWEST THROUGH THURSDAY AS A LARGE TROUGH
CARVES OUT OVER THE WEST. THIS WILL BE A PLAYER IN OUR WEATHER INTO
THE WEEKEND.
THEN LATER IN THE WEEK...IN THE FRIDAY TO SATURDAY NIGHT TIME FRAME
A SECOND POTENTIALLY STRONG SYSTEM WILL AFFECT CENTRAL IOWA. THERE
ARE SIGNIFICANT DIFFERENCES BETWEEN THE MODELS...AT LEAST INITIALLY
AS TO THE EVOLUTION OF THE UPPER LEVEL WAVE...THE SURFACE LOW AND
THE FRONTAL BOUNDARY WITH THE SYSTEM. THE GFS LEAVES THIS AN OPEN
WAVE THROUGH FRIDAY THEN DEVELOPS A LOW OVER SOUTH DAKOTA AS THE
SYSTEM WRAPS UP WHILE THE EURO DEVELOPS A DEEP LOW OVER KANSAS AND
LIFTS IT NORTHEAST. BOTH MODELS PUT THE UPPER LOW OVER SE MN AT 00Z
BUT HOW IT GETS THERE IS AN QUESTION. THE EURO DEVELOPS A MUCH
BETTER DEFORMATION ZONE OVER NORTHERN INTO WEST CENTRAL IOWA WHILE
THE GFS HAS THIS FURTHER NORTH.
THE SURFACE LOW POSITION IS ALSO QUITE DIFFERENT IN PLACEMENT AND
INTENSITY. BOTH MODELS POINT AT SOUTHERN IOWA AND LOCATIONS SOUTH
AND EAST BEING IN A WARM ADVECTION ZONE WITH PRETTY IMPRESSIVE CAPE
FOR MID DECEMBER. THEREFORE I HAD TO PUT IN ISOLATED THUNDER ACROSS
THE SOUTH. PTYPE ELSEWHERE IS VERY DIFFICULT TO PINPOINT AT THIS
POINT. THE NORTH INTO WEST CENTRAL COULD HAVE A MIXED BAG OF PRECIP
CHANGING TO SNOW AND ACCUMULATING. A RAIN/SNOW TRANSITION WILL
OCCUR BETWEEN THERE AND SOUTH BUT THERE IS NOT ENOUGH AGREEMENT
BETWEEN THE MODELS TO SAY WITH ANY CERTAINTY. AT THIS POINT IT
LOOKS MESSY WITH A POTENTIAL FOR SEVERAL PTYPES ACROSS IOWA AND
THUNDER SOUTH. HOWEVER THE MODELS DID SOMETHING SIMILAR WITH THIS
CURRENT SYSTEM AT THAT FAR OUT.
&&
.AVIATION...09/00Z
VFR CONDITIONS IN PLACE ACROSS TAF SITES AT 00Z AND ARE EXPECTED TO
REMAIN THAT WAY INTO THE EVENING. PRECIP...MAINLY VIRGA...WILL
TRAVERSE THE STATE THIS EVENING ALTHOUGH IT MAY REACH THE GROUND IN
ISOLATED INSTANCES OF TRACE AMOUNTS. HOWEVER OVERNIGHT CONDITIONS
ARE EXPECTED TO DETERIORATE QUICKLY DROPPING TO IFR AS MORE
PRECIPITATION DEVELOPS. PRECIP WINDOW IS EXPECTED TO BE AROUND 6-7
HOURS ENDING AT ALL STIES BY MIDDAY. THIS WILL BE FOLLOWED BY WINDS
BECOMING NW WITH GUSTS INTO THE 20S DURING THE AFTERNOON.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...DONAVON
LONG TERM...FAB
AVIATION...SMALL
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 WICHITA KS
926 PM CST SAT DEC 8 2012
.UPDATE...
LOW CLOUDS AND DRIZZLE HAVE OVERSPREAD MUCH OF CENTRAL AND SOUTH
CENTRAL KS THIS EVENING...AS ISENTROPIC LIFT CONTINUES IN THE
295-300K LAYER. THIS WEAK LIFT HAS LED TO SOME SATURATION IN THE
LOWEST LAYERS OF THE ATMOSPHERE...WITH WIDESPREAD STRATUS BUILDING
DOWN AS THE EVENING PROGRESSES WITH DRIZZLE AND SOME AREAS OF FOG.
THIS DRIZZLE AND FOG WILL BE SHORT LIVED...ESPECIALLY ACROSS CENTRAL
KS...AS A STRONG COLD FRONT PUSHES INTO CENTRAL KS BY AROUND 06Z/SUN
AND KEEPS PUSHING SOUTH ACROSS THE REST OF THE REGION LATE TONIGHT
OR EARLY ON SUN. THIS FRONT WILL SHIFT THE WINDS RAPIDLY AROUND TO
THE NORTH AND BECOME GUSTY AT 20 TO 30 MPH. IT WILL ALSO HELP SCOUR
OUT MOST OF THE LOW LEVEL MOISTURE IS IT PUSHES SOUTH...ENDING THE
DRIZZLE AND FOG AS IT MOVES SOUTH.
AS THIS FRONT APPROACHES...WITH A SHORTWAVE PUSHING ACROSS NEB. LIFT
ASSOCIATED WITH THIS FRONT AND SHORTWAVE COULD LEAD TO SOME LIGHT
RAIN ACROSS CEN KS. COULD SEE THIS LIGHT RAIN CHANCE POSSIBLY TURN
OVER OR MIX WITH SOME LIGHT SNOW...AS COLDER AIR ALOFT MOVES ACROSS
NEB BY EARLY ON SUN. BUT LACK OF DEEP MOISTURE WILL MAINLY LEAD TO
VERY LIGHT PRECIPITATION...WITH MAINLY FLURRIES AS IT TURNS OVER TO
SNOW.
KETCHAM
&&
.PREV DISCUSSION... /ISSUED 556 PM CST SAT DEC 8 2012/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
LOW LEVEL ISENTROPIC LIFT FROM THE SOUTH-SOUTHWEST WILL LEAD TO
DETERIORATING FLIGHT CONDITIONS THIS EVENING...AS WIDESPREAD MVFR
CIGS/VSBYS AND AREAS OF IFR CIGS PUSH INTO THE AREA THROUGH THE
EVENING HOURS. BOTH THE NAM/WRF AND GFS NOT HANDLING THIS LOWER
CEILING TREND VERY WELL...WITH THE LATEST RUC40 CLOSER TO REALITY.
EVEN WENT MORE PESSIMISTIC THAN THE RUC ON CEILINGS AND FOG.
A COLD FRONTAL BOUNDARY LOOKS TO ARRIVE AFTER 06Z/SUN ACROSS CENTRAL
KANSAS...AND FURTHER SOUTH ACROSS SOUTH CENTRAL KS AFTER
09-10Z/SUN. THIS WILL LEAD TO CEILINGS BEGINNING TO LIFT WITH
MVFR/VFR CEILINGS FOR THE MORNING HOURS ON SUN. WINDS BEHIND THE
FRONT WILL INCREASE TO 20-30 KTS WITH SOME LIGHT SNOW DEVELOPING
ACROSS PORTIONS OF CENTRAL KANSAS ON SUNDAY. NOT EXPECTING THE LIGHT
SNOW TO RESTRICT VSBYS MUCH...AS THIS WILL BE MAINLY A LIGHT SNOW
EVENT/FLURRY EVENT.
KETCHAM
PREV DISCUSSION... /ISSUED 311 PM CST SAT DEC 8 2012/
DISCUSSION...
MAIN FORECAST CONCERNS ARE PRECIP CHANCES AND TYPE TONIGHT THROUGH
SUN ALONG WITH HOW COLD TO GO FOR SUN-MON.
SYNOPSIS:
STRONG SHORTWAVE IS DIVING OVER THE NORTHERN ROCKIES AND APPROACHING
THE NORTHERN HIGH PLAINS. AT THE SURFACE...TROUGHING EXTENDS FROM SW
SD INTO EASTERN CO. THIS HAS LEFT WARM MOIST FLOW OVER THE SOUTHERN
AND CENTRAL PLAINS WHICH HAS ALLOWED LOW CLOUDS TO MOVE BACK IN
ACROSS MUCH OF THE FORECAST AREA.
TONIGHT-SUN NIGHT:
WITH THE LOW LEVEL WARM MOIST FLOW REMAINING IN PLACE...THINKING
THAT THE LOW CLOUDS WILL MAINTAIN AND WILL LIKELY LOWER A BIT THIS EVENING.
IN ADDITION ALSO FEEL THAT AFTER DARK SOME LIGHT FOG AND DRIZZLE
WILL ACCOMPANY THE LOW CIGS. MID LEVEL LIFT WILL COMMENCE OVER
CENTRAL AND NORTHEAST KS THIS EVENING WHICH SHOULD RESULT IN SOME
LIGHT SHOWERS WITH SOME OF THESE SHOWERS TRANSITIONING TO SOME LIGHT
SNOW AFTER AFTER 3 AM AS MUCH COLDER AIR STARTS TO SPILL-IN FROM THE
NORTH. NOT EXPECTING ANYTHING IN THE WAY OF ACCUMULATION OVERNIGHT.
JUST LIKE THE LAST FEW MODEL RUNS...THE MAIN PIECE OF ENERGY IS
EXPECTED TO BREAK OFF INTO TWO PIECES. ONE WILL MOVE TOWARDS THE
GREAT LAKES WHILE THE OTHER DIVES OVER THE DESERT SW AND EVENTUALLY
THE SOUTHERN PLAINS. STILL THINKING THAT THE PRECIP ON SUN WILL
PRIMARILY BE IN THE FORM OR FLURRIES AND SPRINKLES. THE EXCEPTION
WOULD BE THE EAST AND NORTHEAST FRINGES OF THE FORECAST AREA WHERE
THE DEEPER LIFT AND MOISTURE WILL BE SITUATED. EVEN THE LOCATIONS
THAT DO SEEM SOME SNOW SHOWERS CAN EXPECT TO ONLY PICKUP VERY LIGHT
AMOUNTS. THE MAIN STORY WITH THIS SYSTEM WILL CONTINUE TO BE THE
COLDEST TEMPS OF THE SEASON SO FAR WITH SINGLE DIGITS A GOOD BET FOR
MUCH OF CENTRAL KS MON MORNING.
MON-SAT:
THE LONGWAVE TROUGH IS EXPECTED TO POSITION ITSELF OVER THE CENTRAL
CONUS TO START THE WORK WEEK AS ADDITIONAL UPPER IMPULSES DIVE DOWN
THE BACKSIDE OF THE TROUGH AND ACROSS THE SOUTHERN PLAINS FOR MON
NIGHT INTO TUE. THIS PATTERN WILL RESULT IN A CONTINUATION OF BELOW
NORMAL TEMPS WITH THE MOISTURE AND ASSOCIATED PRECIP CHANCES PUSHED
WELL EAST OF THE FORECAST AREA. BY MID WEEK THE UPPER PATTERN WILL
QUICKLY TRANSITION FROM NW FLOW ALOFT TO SW FLOW BY WED AFTERNOON AS
OUR NEXT SHORTWAVE DIGS OVER THE WEST COAST. THIS WILL GET THE
PLAINS BACK INTO A WARMING PATTERN THAT WILL CONTINUE FOR THU INTO
FRI.
THE SHORTWAVE WILL START TO DIRECTLY IMPACT THE AREA BY FRI INTO
SAT. THE ECMWF IS MUCH MORE COMPACT THE MORE PROGRESSIVE WITH THIS
WAVE COMPARED TO THE GFS. REGARDLESS OF WHICH ONE VERIFIES IT
APPEARS THE BEST SNOW CHANCES WILL BE NORTH OF THE FORECAST AREA
WITH SOME SHOWERS AND EVEN A FEW STORMS POSSIBLE FOR
FRI...TRANSITIONING TO SOME LIGHT SNOW OR FLURRIES FOR FRI NIGHT.
LAWSON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 35 38 13 35 / 10 10 10 0
HUTCHINSON 34 35 12 36 / 10 10 10 0
NEWTON 34 37 12 35 / 10 20 10 0
ELDORADO 36 39 14 34 / 10 20 10 0
WINFIELD-KWLD 37 39 15 36 / 10 20 10 0
RUSSELL 28 32 6 39 / 20 10 10 0
GREAT BEND 31 33 7 38 / 10 10 10 0
SALINA 31 32 10 37 / 20 10 10 0
MCPHERSON 34 35 11 36 / 20 10 10 0
COFFEYVILLE 44 45 19 36 / 10 30 10 10
CHANUTE 42 43 18 34 / 10 30 10 10
IOLA 41 43 17 33 / 10 30 10 10
PARSONS-KPPF 43 44 18 35 / 10 30 10 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
802 PM MST SAT DEC 8 2012
.UPDATE...
ISSUED AT 757 PM MST SAT DEC 8 2012
PER SATELLITE AND LATEST MODEL DATA INCREASED CLOUD COVER THROUGH
TOMORROW MORNING. LOOKING AT CURRENT SURFACE OBSERVATION DATA AND
CONSIDERING THE HIGHER WINDS/MORE CLOUD COVER...CHOSE TO RAISE
MINS A LITTLE WHICH DOES FIT WITH SOME OF THE NEWER GUIDANCE.
CURRENT PRECIPITATION FORECAST LOOKS FINE. WINDS WILL BEGIN
GUSTING TO JUST UNDER WIND ADVISORY CRITERIA. IT LOOKS CLOSE FOR
WIND ADVISORY AND WILL LET THE OVERNIGHT SHIFT ADDRESS THAT. GRIDS
ARE ALREADY REFLECTING IT.
UPDATE ISSUED AT 605 PM MST SAT DEC 8 2012
JUST COMPLETED AN UPDATE. FIRST FRONT IN A SERIES OF FRONTS
ALREADY BLASTING THROUGH WHICH IS FASTER THAN ANY MODEL DEPICTION
OR WHAT THE GRIDS HAD WHICH IS NOT UNCOMMON IN THIS SCENARIO. NOT
ONLY IS THE FRONT THROUGH...BUT WIND SPEEDS ALREADY TO NEAR 40 MPH
IN SOME LOCATIONS. RUC WAS THE FASTEST MODEL BUT WAS STILL A LITTLE
SLOW AND UNDERDONE ON THE SPEEDS. SO USED IT AND MODIFIED WITH
REALITY. HOPEFULLY NEWER MODEL DATA WILL CATCH UP WITH THIS. ALSO
INCREASED SPEEDS FOR LATER TONIGHT AND TOMORROW AS WELL WITH WHAT
LOOKS TO BE DECENT MIXING. CONSIDERING THE COLD AIR ADVECTION
ALREADY OCCURRING...THERE MAY NOT BE ANY LOW LEVEL INVERSION TO
OVERCOME AND WIND SPEEDS MAY BE EVEN HIGHER THAN WHAT I HAVE
DEPICTED. WILL CONTINUE TO WATCH AND TWEAK AS NEWER DATA COMES IN.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 1059 AM MST SAT DEC 8 2012
EXCEPT FOR THE COLD AIR MOVING IN BEHIND THE FRONT THIS EVENING
AND OVERNIGHT...THIS EVENT IS BEGINNING TO LOOK MORE LIKE A NON-
EVENT. HAVE TONED DOWN THE MENTION OF ANY ACCUMULATING SNOW AND
HAVE PUT IN A MENTION OF SPRINKLES OR FLURRIES IN THE FAR
NORTHWEST CORNER OF THE FORECAST AREA BEFORE 00Z WITH A MORE
EXTENSIVE AREA OF FLURRIES ALONG AND BEHIND THE FRONT AS IT MOVES
THROUGH THE FORECAST AREA TONIGHT. THE NAM CONTINUES TO BE DRY WITH THE
ECMWF AND GFS ONLY PRODUCING AROUND ONE HUNDREDTH OF QPF ALONG THE
NORTHERN AND WESTERN FRINGES OF THE FORECAST AREA. FLURRIES WILL
DIMINISH EARLY SUNDAY WITH SKIES BEGINNING TO CLEAR BY LATE SUNDAY
AFTERNOON AS SURFACE HIGH PRESSURE BEGINS TO MOVE INTO THE REGION.
BECAUSE OF THE DECREASING CLOUDS COVER AND SLACKENING WINDS SUNDAY
NIGHT...EXPECT THE COLDEST TEMPERATURES OF THE SEASON WITH LOWS
DROPPING DOWN TO AROUND ZERO IN SOME LOCATIONS. WIND CHILL BELOW
ZERO WILL BE COMMON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 112 PM MST SAT DEC 8 2012
SUNDAY NIGHT THROUGH TUESDAY NIGHT THE BASE OF THE LONG WAVE TROUGH
WILL REMAIN OVER THE AREA.
SUNDAY NIGHT THE TROUGH AXIS...FROM THE SHORT WAVE TROUGH
RESPONSIBLE FOR THE WINTER STORM OVER THE NORTHERN PLAINS...WILL
MOVE THROUGH THE AREA. UNFORTUNATELY DRIER AIR WILL BE OVER THE
AREA BY THE TIME THE TROUGH AXIS MOVES THROUGH AND THE LEFT
ENTRANCE OF THE 500-300MB JET WILL BE OVER THE AREA AHEAD OF THE
TROUGH AXIS...LEADING TO DRY CONDITIONS FOR THE AREA. WINDS WILL
DECREASE DURING THE EVENING AS A SURFACE HIGH BUILDS INTO THE
AREA. WITH LITTLE TO NO WIND AND CLEAR SKIES...TEMPERATURES WILL
FALL TO THE SINGLE DIGITS. ANY WIND THAT DOES DEVELOP WILL PRODUCE
WIND CHILL VALUES NEAR 15 BELOW ZERO.
MONDAY SEVERAL WEAKER SHORT WAVE TROUGHS MOVE THROUGH...BUT THERE
WILL BE LITTLE TO NO MOISTURE TO WORK WITH. DURING THE LATE
AFTERNOON/EVENING AREA SOUNDINGS SATURATE AS MOISTURE MOVES INTO THE
AREA BEHIND A SURFACE AND UPPER LEVEL TROUGH. HOWEVER THE
INCREASED MOISTURE WILL BE IN THE SUBSIDENCE AREA BEHIND THE SHORT
WAVE TROUGH.
FOR THE TUESDAY THROUGH SATURDAY PERIOD...DRY CONDITIONS WILL
CONTINUE TO PREVAIL. THE LONG WAVE TROUGH MOVES EAST TUESDAY
ALLOWING A LONG WAVE RIDGE TO MOVE OVER THE CENTRAL PLAINS THROUGH
THE MAJORITY OF NEXT WEEK. MEANWHILE THE NEXT SHORT WAVE TROUGH
MOVES ONSHORE WEDNESDAY...APPROACHING THE AREA FRIDAY. MODELS AGREE
WITH THE TRACK OF THE TROUGH...MOVING IT OVER THE TEXAS AND OKLAHOMA
PANHANDLES. THE POSITION OF THE TROUGH IS STILL TOO FAR SOUTH FOR
THE AREA TO RECEIVE ANY PRECIPITATION. HOWEVER THE MODELS HAVE
TRENDED FURTHER NORTH WITH THE TROUGH SINCE YESTERDAY. FRIDAY NIGHT
THE GEFS MEMBERS INDICATED A SLIGHT CHANCE FOR SOME PRECIPITATION
OVER THE EASTERN PART OF THE AREA. GFS ISENTROPIC LIFT DOES SHOW
SOME LIFT AND MOISTURE CO-LOCATED AROUND 600MB OVER THOSE
LOCATIONS. IF THIS FEATURE IS STILL THERE TOMORROW...SLIGHT CHANCES
MAY NEED TO BE ADDED FOR THE EAST FRIDAY NIGHT.
TEMPERATURES WILL BE NEAR NORMAL...WITH A SMALL WARMING TREND
THROUGH THE PERIOD. A COLD FRONT WILL MOVE THROUGH FRIDAY BEHIND
THE UPPER LEVEL TROUGH...BUT THE COOLER AIR MASS BEHIND THE FRONT
WILL QUICKLY MOVE EAST FOLLOWING THE UPPER LEVEL TROUGH. THIS WILL
ALLOW TEMPERATURES FOR SATURDAY TO REMAIN LARGELY UNAFFECTED BY THE
FRONTAL PASSAGE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 440 PM MST SAT DEC 8 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. A SERIES OF COLD
FRONTS WILL PUSH ACROSS THE AREA THROUGH THE MORNING HOURS. LITTLE
LEVEL MOISTURE IS AVIALABLE FOR LIFT WITH SOME FLURRIES POSSIBLE
AS THE INITIAL STRONG PUSHES ACROSS THE AREA DURING THE LATE TO
MID EVENING HOURS. EXPECT THE FLURRIES AND ANY LOW CLOUDS...WHICH
AM NOT EXPECTING A LOT OF AT THIS TIME...WILL PUSH THROUGH RAPIDLY
AND WILL BE DONE BY 06Z OR 07Z. OTHERWISE...GUSTY NORTH TO
NORTHWEST WINDS WILL BE IN PLACE FOR A MAJORITY OF THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...LOCKHART
LONG TERM...JTL
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
615 PM MST SAT DEC 8 2012
.UPDATE...
ISSUED AT 605 PM MST SAT DEC 8 2012
JUST COMPLETED AN UPDATE. FIRST FRONT IN A SERIES OF FRONTS
ALREADY BLASTING THROUGH WHICH IS FASTER THAN ANY MODEL DEPICTION
OR WHAT THE GRIDS HAD WHICH IS NOT UNCOMMON IN THIS SCENARIO. NOT
ONLY IS THE FRONT THROUGH...BUT WIND SPEEDS ALREADY TO NEAR 40 MPH
IN SOME LOCATIONS. RUC WAS THE FASTEST MODEL BUT WAS STILL A LITTLE
SLOW AND UNDERDONE ON THE SPEEDS. SO USED IT AND MODIFIED WITH
REALITY. HOPEFULLY NEWER MODEL DATA WILL CATCH UP WITH THIS. ALSO
INCREASED SPEEDS FOR LATER TONIGHT AND TOMORROW AS WELL WITH WHAT
LOOKS TO BE DECENT MIXING. CONSIDERING THE COLD AIR ADVECTION
ALREADY OCCURRING...THERE MAY NOT BE ANY LOW LEVEL INVERSION TO
OVERCOME AND WIND SPEEDS MAY BE EVEN HIGHER THAN WHAT I HAVE
DEPICTED. WILL CONTINUE TO WATCH AND TWEAK AS NEWER DATA COMES IN.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 1059 AM MST SAT DEC 8 2012
EXCEPT FOR THE COLD AIR MOVING IN BEHIND THE FRONT THIS EVENING
AND OVERNIGHT...THIS EVENT IS BEGINNING TO LOOK MORE LIKE A NON-
EVENT. HAVE TONED DOWN THE MENTION OF ANY ACCUMULATING SNOW AND
HAVE PUT IN A MENTION OF SPRINKLES OR FLURRIES IN THE FAR
NORTHWEST CORNER OF THE FORECAST AREA BEFORE 00Z WITH A MORE
EXTENSIVE AREA OF FLURRIES ALONG AND BEHIND THE FRONT AS IT MOVES
THROUGH THE FORECAST AREA TONIGHT. THE NAM CONTINUES TO BE DRY WITH THE
ECMWF AND GFS ONLY PRODUCING AROUND ONE HUNDREDTH OF QPF ALONG THE
NORTHERN AND WESTERN FRINGES OF THE FORECAST AREA. FLURRIES WILL
DIMINISH EARLY SUNDAY WITH SKIES BEGINNING TO CLEAR BY LATE SUNDAY
AFTERNOON AS SURFACE HIGH PRESSURE BEGINS TO MOVE INTO THE REGION.
BECAUSE OF THE DECREASING CLOUDS COVER AND SLACKENING WINDS SUNDAY
NIGHT...EXPECT THE COLDEST TEMPERATURES OF THE SEASON WITH LOWS
DROPPING DOWN TO AROUND ZERO IN SOME LOCATIONS. WIND CHILL BELOW
ZERO WILL BE COMMON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 112 PM MST SAT DEC 8 2012
SUNDAY NIGHT THROUGH TUESDAY NIGHT THE BASE OF THE LONG WAVE TROUGH
WILL REMAIN OVER THE AREA.
SUNDAY NIGHT THE TROUGH AXIS...FROM THE SHORT WAVE TROUGH
RESPONSIBLE FOR THE WINTER STORM OVER THE NORTHERN PLAINS...WILL
MOVE THROUGH THE AREA. UNFORTUNATELY DRIER AIR WILL BE OVER THE
AREA BY THE TIME THE TROUGH AXIS MOVES THROUGH AND THE LEFT
ENTRANCE OF THE 500-300MB JET WILL BE OVER THE AREA AHEAD OF THE
TROUGH AXIS...LEADING TO DRY CONDITIONS FOR THE AREA. WINDS WILL
DECREASE DURING THE EVENING AS A SURFACE HIGH BUILDS INTO THE
AREA. WITH LITTLE TO NO WIND AND CLEAR SKIES...TEMPERATURES WILL
FALL TO THE SINGLE DIGITS. ANY WIND THAT DOES DEVELOP WILL PRODUCE
WIND CHILL VALUES NEAR 15 BELOW ZERO.
MONDAY SEVERAL WEAKER SHORT WAVE TROUGHS MOVE THROUGH...BUT THERE
WILL BE LITTLE TO NO MOISTURE TO WORK WITH. DURING THE LATE
AFTERNOON/EVENING AREA SOUNDINGS SATURATE AS MOISTURE MOVES INTO THE
AREA BEHIND A SURFACE AND UPPER LEVEL TROUGH. HOWEVER THE
INCREASED MOISTURE WILL BE IN THE SUBSIDENCE AREA BEHIND THE SHORT
WAVE TROUGH.
FOR THE TUESDAY THROUGH SATURDAY PERIOD...DRY CONDITIONS WILL
CONTINUE TO PREVAIL. THE LONG WAVE TROUGH MOVES EAST TUESDAY
ALLOWING A LONG WAVE RIDGE TO MOVE OVER THE CENTRAL PLAINS THROUGH
THE MAJORITY OF NEXT WEEK. MEANWHILE THE NEXT SHORT WAVE TROUGH
MOVES ONSHORE WEDNESDAY...APPROACHING THE AREA FRIDAY. MODELS AGREE
WITH THE TRACK OF THE TROUGH...MOVING IT OVER THE TEXAS AND OKLAHOMA
PANHANDLES. THE POSITION OF THE TROUGH IS STILL TOO FAR SOUTH FOR
THE AREA TO RECEIVE ANY PRECIPITATION. HOWEVER THE MODELS HAVE
TRENDED FURTHER NORTH WITH THE TROUGH SINCE YESTERDAY. FRIDAY NIGHT
THE GEFS MEMBERS INDICATED A SLIGHT CHANCE FOR SOME PRECIPITATION
OVER THE EASTERN PART OF THE AREA. GFS ISENTROPIC LIFT DOES SHOW
SOME LIFT AND MOISTURE CO-LOCATED AROUND 600MB OVER THOSE
LOCATIONS. IF THIS FEATURE IS STILL THERE TOMORROW...SLIGHT CHANCES
MAY NEED TO BE ADDED FOR THE EAST FRIDAY NIGHT.
TEMPERATURES WILL BE NEAR NORMAL...WITH A SMALL WARMING TREND
THROUGH THE PERIOD. A COLD FRONT WILL MOVE THROUGH FRIDAY BEHIND
THE UPPER LEVEL TROUGH...BUT THE COOLER AIR MASS BEHIND THE FRONT
WILL QUICKLY MOVE EAST FOLLOWING THE UPPER LEVEL TROUGH. THIS WILL
ALLOW TEMPERATURES FOR SATURDAY TO REMAIN LARGELY UNAFFECTED BY THE
FRONTAL PASSAGE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 440 PM MST SAT DEC 8 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. A SERIES OF COLD
FRONTS WILL PUSH ACROSS THE AREA THROUGH THE MORNING HOURS. LITTLE
LEVEL MOISTURE IS AVIALABLE FOR LIFT WITH SOME FLURRIES POSSIBLE
AS THE INITIAL STRONG PUSHES ACROSS THE AREA DURING THE LATE TO
MID EVENING HOURS. EXPECT THE FLURRIES AND ANY LOW CLOUDS...WHICH
AM NOT EXPECTING A LOT OF AT THIS TIME...WILL PUSH THROUGH RAPIDLY
AND WILL BE DONE BY 06Z OR 07Z. OTHERWISE...GUSTY NORTH TO
NORTHWEST WINDS WILL BE IN PLACE FOR A MAJORITY OF THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...LOCKHART
LONG TERM...JTL
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS WICHITA KS
556 PM CST SAT DEC 8 2012
.AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
LOW LEVEL ISENTROPIC LIFT FROM THE SOUTH-SOUTHWEST WILL LEAD TO
DETERIORATING FLIGHT CONDITIONS THIS EVENING...AS WIDESPREAD MVFR
CIGS/VSBYS AND AREAS OF IFR CIGS PUSH INTO THE AREA THROUGH THE
EVENING HOURS. BOTH THE NAM/WRF AND GFS NOT HANDLING THIS LOWER
CEILING TREND VERY WELL...WITH THE LATEST RUC40 CLOSER TO REALITY.
EVEN WENT MORE PESSIMISTIC THAN THE RUC ON CEILINGS AND FOG.
A COLD FRONTAL BOUNDARY LOOKS TO ARRIVE AFTER 06Z/SUN ACROSS CENTRAL
KANSAS...AND FURTHER SOUTH ACROSS SOUTH CENTRAL KS AFTER
09-10Z/SUN. THIS WILL LEAD TO CEILINGS BEGINNING TO LIFT WITH
MVFR/VFR CEILINGS FOR THE MORNING HOURS ON SUN. WINDS BEHIND THE
FRONT WILL INCREASE TO 20-30 KTS WITH SOME LIGHT SNOW DEVELOPING
ACROSS PORTIONS OF CENTRAL KANSAS ON SUNDAY. NOT EXPECTING THE LIGHT
SNOW TO RESTRICT VSBYS MUCH...AS THIS WILL BE MAINLY A LIGHT SNOW
EVENT/FLURRY EVENT.
KETCHAM
&&
.PREV DISCUSSION... /ISSUED 311 PM CST SAT DEC 8 2012/
DISCUSSION...
MAIN FORECAST CONCERNS ARE PRECIP CHANCES AND TYPE TONIGHT THROUGH
SUN ALONG WITH HOW COLD TO GO FOR SUN-MON.
SYNOPSIS:
STRONG SHORTWAVE IS DIVING OVER THE NORTHERN ROCKIES AND APPROACHING
THE NORTHERN HIGH PLAINS. AT THE SURFACE...TROUGHING EXTENDS FROM SW
SD INTO EASTERN CO. THIS HAS LEFT WARM MOIST FLOW OVER THE SOUTHERN
AND CENTRAL PLAINS WHICH HAS ALLOWED LOW CLOUDS TO MOVE BACK IN
ACROSS MUCH OF THE FORECAST AREA.
TONIGHT-SUN NIGHT:
WITH THE LOW LEVEL WARM MOIST FLOW REMAINING IN PLACE...THINKING
THAT THE LOW CLOUDS WILL MAINTAIN AND WILL LIKELY LOWER A BIT THIS EVENING.
IN ADDITION ALSO FEEL THAT AFTER DARK SOME LIGHT FOG AND DRIZZLE
WILL ACCOMPANY THE LOW CIGS. MID LEVEL LIFT WILL COMMENCE OVER
CENTRAL AND NORTHEAST KS THIS EVENING WHICH SHOULD RESULT IN SOME
LIGHT SHOWERS WITH SOME OF THESE SHOWERS TRANSITIONING TO SOME LIGHT
SNOW AFTER AFTER 3 AM AS MUCH COLDER AIR STARTS TO SPILL-IN FROM THE
NORTH. NOT EXPECTING ANYTHING IN THE WAY OF ACCUMULATION OVERNIGHT.
JUST LIKE THE LAST FEW MODEL RUNS...THE MAIN PIECE OF ENERGY IS
EXPECTED TO BREAK OFF INTO TWO PIECES. ONE WILL MOVE TOWARDS THE
GREAT LAKES WHILE THE OTHER DIVES OVER THE DESERT SW AND EVENTUALLY
THE SOUTHERN PLAINS. STILL THINKING THAT THE PRECIP ON SUN WILL
PRIMARILY BE IN THE FORM OR FLURRIES AND SPRINKLES. THE EXCEPTION
WOULD BE THE EAST AND NORTHEAST FRINGES OF THE FORECAST AREA WHERE
THE DEEPER LIFT AND MOISTURE WILL BE SITUATED. EVEN THE LOCATIONS
THAT DO SEEM SOME SNOW SHOWERS CAN EXPECT TO ONLY PICKUP VERY LIGHT
AMOUNTS. THE MAIN STORY WITH THIS SYSTEM WILL CONTINUE TO BE THE
COLDEST TEMPS OF THE SEASON SO FAR WITH SINGLE DIGITS A GOOD BET FOR
MUCH OF CENTRAL KS MON MORNING.
MON-SAT:
THE LONGWAVE TROUGH IS EXPECTED TO POSITION ITSELF OVER THE CENTRAL
CONUS TO START THE WORK WEEK AS ADDITIONAL UPPER IMPULSES DIVE DOWN
THE BACKSIDE OF THE TROUGH AND ACROSS THE SOUTHERN PLAINS FOR MON
NIGHT INTO TUE. THIS PATTERN WILL RESULT IN A CONTINUATION OF BELOW
NORMAL TEMPS WITH THE MOISTURE AND ASSOCIATED PRECIP CHANCES PUSHED
WELL EAST OF THE FORECAST AREA. BY MID WEEK THE UPPER PATTERN WILL
QUICKLY TRANSITION FROM NW FLOW ALOFT TO SW FLOW BY WED AFTERNOON AS
OUR NEXT SHORTWAVE DIGS OVER THE WEST COAST. THIS WILL GET THE
PLAINS BACK INTO A WARMING PATTERN THAT WILL CONTINUE FOR THU INTO
FRI.
THE SHORTWAVE WILL START TO DIRECTLY IMPACT THE AREA BY FRI INTO
SAT. THE ECMWF IS MUCH MORE COMPACT THE MORE PROGRESSIVE WITH THIS
WAVE COMPARED TO THE GFS. REGARDLESS OF WHICH ONE VERIFIES IT
APPEARS THE BEST SNOW CHANCES WILL BE NORTH OF THE FORECAST AREA
WITH SOME SHOWERS AND EVEN A FEW STORMS POSSIBLE FOR
FRI...TRANSITIONING TO SOME LIGHT SNOW OR FLURRIES FOR FRI NIGHT.
LAWSON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 35 38 13 35 / 10 10 10 0
HUTCHINSON 34 35 12 36 / 10 10 10 0
NEWTON 34 37 12 35 / 10 20 10 0
ELDORADO 36 39 14 34 / 10 20 10 0
WINFIELD-KWLD 37 39 15 36 / 10 20 10 0
RUSSELL 28 30 6 39 / 20 10 10 0
GREAT BEND 31 30 7 38 / 10 10 10 0
SALINA 31 32 10 37 / 20 10 10 0
MCPHERSON 34 35 11 36 / 20 10 10 0
COFFEYVILLE 44 45 19 36 / 10 30 10 10
CHANUTE 42 43 18 34 / 10 30 10 10
IOLA 41 43 17 33 / 10 30 10 10
PARSONS-KPPF 43 44 18 35 / 10 30 10 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
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 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
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 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 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 MARQUETTE MI
741 PM EST SAT DEC 8 2012
.UPDATE...
ISSUED AT 739 PM EST SAT DEC 8 2012
WITH MOCLR SKIES OVER THE W HALF OF UPR MI UNDER SFC RDG AXIS/PWAT
0.18 INCH AS OBSVD ON THE 00Z GRB RAOB...SFC TEMPS HAVE ALREADY
REACHED FCST MINS EARLY THIS EVNG. SO TENDED TO LOWER THESE NUMBERS
A COUPLE OF DEGREES OVER THE W HALF BEFORE INCRSG HI CLDS FM THE SW
ARRIVE BY MIDNGT AND AT LEAST STEADY OFF THE TEMP DROP.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 340 PM EST SAT DEC 8 2012
HIGH PRESSURE IS CURRENTLY LOCATED IN MANITOBA AND ONTARIO...WITH A
RIDGE STRETCHING SOUTHEAST INTO WESTERN UPPER MI AND WI. LIGHT
NORTHWEST FLOW...WITH RUC ANALYZED H850 OF -10 TO -12C...HAS LED TO
LAKE EFFECT CLOUDS AND LIGHT SNOW SHOWERS THROUGH THIS AFTERNOON IN
THE TRADITIONAL NORTHWEST FLOW LOCATIONS.
UPSTREAM...PV ANOMALY IN SRN SD AND NW NEBRASKA WILL SHIFT ENE
TONIGHT AND INTO MN BY 12Z SUNDAY...WITH THE SURFACE LOW FOLLOWING
SUIT. THIS ANOMALY WILL SHIFT NORTHEAST THROUGH WESTERN UPPER
MICHIGAN THROUGH THE DAY ON SUNDAY AND BE WEAKENING DUE TO INFLUENCE
OF SECOND ANOMALY ENTERING NORTHERN MN AND THE SOUTHERN WAVE
BECOMING MORE DOMINATE AS IT DIVES SOUTHEAST THROUGH THE CENTRAL
ROCKIES DURING THE DAY ON SUNDAY. THIS...COMBINED WITH A
STRENGTHENING JET OVER THE OHIO VALLEY ON SUNDAY...WILL ALLOW A
SECONDARY LOW TO DEVELOP IN THE OHIO VALLEY REGION DURING THE DAY
AND PRODUCE A BROAD AREA OF LOW PRESSURE WHICH TRANSITIONS THE LOW
OVER OUR AREA TO A TROUGH. STILL DIFFERENCES IN THE MODELS...BOTH
RUN-TO-RUN AND BETWEEN MODELS...WITH THE POTENTIAL WEAKENING/SPEED
OF THE PV ANOMALY AND THE LOCATION OF THE ASSOCIATED SURFACE TROUGH
HEADING INTO SUNDAY AFTERNOON/EVENING. LATEST TRENDS IN THE MODELS
ARE FOR A SLOWER MOVEMENT OF THE PV ANOMALY THROUGH UPPER MICHIGAN
ON SUNDAY...WHICH KEEPS THE SURFACE TROUGH AXIS OVER
NORTHERN/CENTRAL WISCONSIN.
TONIGHT...THE HIGH PRESSURE RIDGE EXITING TO THE NORTHEAST WILL
PRODUCE QUIET WEATHER BEFORE THE SYSTEM. UPSTREAM DRYING THIS
AFTERNOON HAS ATE AWAY AT SOME OF THE LAKE EFFECT CLOUDS OVER THE
WEST AND ONCE DAYTIME HEATING IS LOST...EXPECT THE SAME TO OCCUR
OVER THE INTERIOR LOCATIONS THIS EVENING. THIS CLEARING WILL MAKE
FOR TRICKY LOW TEMPERATURES TONIGHT AND FOLLOWED THE PREVIOUS SHIFT
BY TRENDED THEM DOWN A LITTLE MORE AS PWATS 65 PERCENT OF NORMAL
AND THERE ARE LIGHT WINDS. WENT WITH LOWS IN UPPER TEENS...BUT BASED
OFF HOW QUICKLY TEMPS FELL THIS MORNING IN CLEARING AREAS...THAT MAY
NOT BE COLD ENOUGH. OTHERWISE...MID/HIGH LEVEL CLOUDS WILL BE ON THE
INCREASE FROM THE SOUTHWEST WITH THE APPROACHING SYSTEM.
SUNDAY...PRECIPITATION BUILDS IN FROM SOUTHWEST TO NORTHEAST THROUGH
THE DAY. STARTING BETWEEN 12-15Z NEAR KIWD...LATE MORNING OR EARLY
AFTERNOON OVER THE CENTRAL...AND MID/LATE AFTERNOON OVER THE EAST.
WITH THE LATEST SLOWER TRENDS...HAVE DELAYED THE START A COUPLE OF
HOURS FROM THE PREVIOUS SHIFT. PLENTY OF COLD AIR ALOFT...SO EXPECT
PRECIPITATION TO BE AS ALL SNOW. AS FOR FORCING...BEST MID LEVEL WAA
IS FOCUSED OVER THE SOUTH CENTRAL AND NEAR LAKE MICHIGAN THROUGH
THE DAY. THIS LINES UP WITH WEAK FGEN BETWEEN H850-650 OVER THE AREA
FOR THE AFTERNOON...BUT SEEMS TO FOCUS OVER THE SOUTHEAST HALF OF
THE CWA LATE IN THE AFTERNOON. IN ADDITION...BROAD 280-290K
ISENTROPIC ASCENT WILL SPREAD OVER THE CWA DURING THE DAY.
FINALLY...H850 TEMPS AROUND -9C SHOULD FAVOR SOME LAKE ENHANCEMENT
FOR THE KEWEENAW AND ALSO FOR LOCATIONS NEAR LAKE MICHIGAN FAVORED
BY ESE WINDS.
WITH THE SLIGHT DELAY WITH THE SLOWER ARRIVAL OF THE PV ANOMALY AND
SURFACE TROUGH BEING A LITTLE FARTHER SOUTH...BEST PRECIPITATION
STRADDLES THE SHORT/LONG TERM TRANSITION. ALL IN ALL...MODEL QPF
FOR SUNDAY INTO SUNDAY NIGHT WITH THE SYNOPTIC FEATURES IS IN THE
0.25-0.4IN FOR MOST AREAS AND WHEN COMBINED WITH A SNOW RATIO AROUND
13-15 TO 1...WOULD PUT 3 TO 6 INCHES OF SYNOPTIC SNOW OVER THE
AREA THROUGH SUNDAY EVENING. OUTSIDE OF ANY LAKE ENHANCEMENT...THE
HIGHEST AMOUNTS SHOULD LINE UP ALONG THE WISCONSIN BORDER WITH THE
SLIGHT SOUTH SHIFT OF THE SURFACE TROUGH. THE LONG TERM DISCUSSION
WILL COVER THE BULK OF THE HEADLINES...BUT DID DROP THE WATCH OVER
THE WESTERN COUNTIES AND HAVE STARTED A LONGER PERIOD ADVISORY FROM
WEST TO EAST THROUGH THE DAY ON SUNDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 PM EST SAT DEC 8 2012
MAIN CONCERN IS WITH SNOWFALL FORECAST FOR THE FIRST 24 HOURS OF THE
LONG TERM.
SUN NIGHT/MON...IN GENERAL...MODELS ARE IN GOOD AGREEMENT...BUT
THERE ARE SUBTLE VARIATIONS AT SMALLER SCALES THAT BECOME MAGNIFIED
IN THE SNOWFALL FORECAST. THE DIFFICULTY AND UNCERTAINTY IS DUE TO
THE FACT THAT THE SYSTEM OVER THE REGION SUN NIGHT WILL BE MERGING
WITH A SRN STREAM SYSTEM OVER THE OHIO VALLEY...PLUS THE FACT THAT
MODELS HAVE A HARD TIME CONSISTENTLY HANDLING THE PV ANOMALIES THAT
WILL DRIVE A GOOD PORTS OF THE SNOWFALL WITH THIS SYSTEM. LATEST
RUNS OF THE GFS/NAM/REGIONAL GEM/REGIONAL WRF ARE NOW IN BETTER
AGREEMENT IN BRINGING THE WEAKENING PRIMARY PV ANOMALY FROM NW WI AT
00Z MON TO CENTRAL UPPER MI AROUND 06Z MON...THEN SHEARING IT OUT
AND PUSHING IT NORTHEAST BY 12Z MON. MEANWHILE...THE SECONDARY PV
ANOMALY WILL ROTATE INTO CENTRAL/SRN WI...FARTHER S THAN PREVIOUS
RUNS OF THE MODELS. THE TIMING/LOCATION OF THE PV ANOMALIES IS
CONSISTENT WITH THE OVERALL TREND OVER THE LAST FEW RUNS OF THE
MODELS IN SLOWING THE SYSTEM DOWN AND MOVING IT FARTHER S. THE
RESULTING SFC TROUGH LOOKS TO STAY TO THE S OF THE CWA OVER
CENTRAL/NRN WI. LOW LEVEL FLOW WILL GENERALLY BE ELY AT 00Z MON WITH
850MB TEMPS AROUND -9C. BY 06Z MON...LOW LEVEL WINDS BACK TO MORE
ENE...THEN TO NNE BY 12Z MON AS 850MB TEMPS FALL TO -11C. SYNOPTIC
SNOWFALL AMOUNTS WILL BE HIGHEST OVER THE SRN HALF OF UPPER MI SUN
NIGHT...BUT THAT SHOULD BE OFFSET SOME BY UPSLOPE FLOW IN SOME NRN
LOCATIONS...PARTICULARLY NCENTRAL UPPER MI AND THE KEWEENAW...THEN
OVER THE WRN U.P. LATER SUN NIGHT. 850MB TEMPS FALL ANOTHER COUPLE
OF DEGREES THROUGH THE DAY MON WHILE FLOW BECOMES INCREASING
ANTICYCLONIC AS THE SFC TROUGH MOVES QUICKLY E AND A RIDGE MOVES
OVER WRN LAKE SUPERIOR BY 00Z TUE. THUS...EXPECT LES FROM NNW WINDS
MON MORNING...DIMINISHING THROUGH MON EVENING. WITH THIS TYPE OF
SYSTEM THERE IS INHERENT UNCERTAINTY THAT WILL PROBABLY NOT BE
RESOLVED UNTIL THE SYSTEM IS ON THE DOORSTEP OF THE CWA...SO
CONFIDENCE IN SNOWFALL AMOUNTS IS STILL SOMEWHAT LIMITED. STORM
TOTAL SNOWFALL AMOUNTS OF 3 TO 6 INCHES IS EXPECTED...WITH SOME
LOCALLY HIGHER AMOUNTS POSSIBLE IN THE HIGHER TERRAIN OF WRN
GOGEBIC/ONTONAGON COUNTIES AND NW MARQUETTE/NE BARAGA COUNTIES.
DECIDED IN COORDINATION WITH SHORT TERM SHIFT TO ISSUE WINTER WX
ADVISORIES OVER THE ENTIRE CWA. COULD SEE SOME LOCATIONS GO SLIGHTLY
ABOVE ADVISORY CRITERIA...BUT NOT CONFIDENT ENOUGH IN THAT TO
JUSTIFY WARNING. ALSO...THE TIME THAT THE HEAVIEST SNOW WILL FALL
/SUN EVENING AND EARLY SUN NIGHT/ IS NOT A HIGH IMPACT TIME TRAVEL
WISE...PLUS THE FACT THAT THE STORM TOTAL WILL OCCUR OVER 24 HOURS
OR MORE. ALSO DECIDED ON THE ADVISORY WITH THE IDEA THAT IT WOULD BE
EASIER TO UPGRADE TO A WARNING IF NEEDED THAN HAVE TO CANCEL
WARNINGS AND ISSUE AN ADVISORY IF THE BORDERLINE WARNING AMOUNTS DO
NOT OCCUR...WHICH WOULD LEAD TO A MISSED EVENT FOR
VERIFICATION...SORT OF THE PATH OF LEAST REGRET.
A VERY WEAK SHORTWAVE TROUGH MOVES ACROSS THE AREA TUE INTO TUE
NIGHT...BRINGING SE FLOW OFF LAKE MICHIGAN FROM 12Z TUE INTO WED.
THIS SHOULD LEAD TO LES OFF LAKE MI INTO ERN UPPER MI...ESPECIALLY
SERN SCHOOLCRAFT COUNTY. INVERSION HEIGHTS SHOULD BE AROUND 10KFT
ACCORDING TO THE NAM/GFS WITH UNIDIRECTIONAL WINDS. THE RESULTING
LES BAND SHOULD BE A LARGER MORE DOMINANT ONE...BUT SHOULD ALSO NOT
STAY IN ONE PLACE TOO LONG AS WINDS STEADILY VEER. EVEN SO...MAY END
UP BEING CLOSE TO ADVISORY AMOUNTS. WINDS WILL BECOME WLY ENOUGH
BEHIND THE TROUGH BY 06Z WED TO BRING LES TO NW UPPER MI...BUT WINDS
QUICKLY BECOME ANTICYCLONIC BY 12Z WED AS A SFC RIDGE MOVES TO WRN
LAKE SUPERIOR...SO LIGHTER SNOW AMOUNTS ARE EXPECTED THERE.
A SLIGHTLY STRONGER SYSTEM WILL MOVE N OF THE AREA THU AND DRAW
WARMER TEMPS IN THE CWA...BUT NO SIGNIFICANT PRECIP IS EXPECTED.
HIGHS IN THE MID TO UPPER 30S SEEMS REASONABLE. PRETTY QUIET AFTER
THAT UNTIL MODELS INDICATE A MUCH STRONGER LOW PRESSURE SYSTEM
MOVING NEARBY ON SAT. MODELS ARE IN GOOD AGREEMENT FOR HOW FAR OUT
THE SYSTEM IS...SO WILL USE CONSENSUS OF MODELS FOR THE FORECAST
PAST TUE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 622 PM EST SAT DEC 8 2012
ALTHOUGH SOME INTERVALS OF MVFR CIGS ARE POSSIBLE TNGT...EXPECT
PREDOMINANT VFR CONDITIONS THRU 12Z AT ALL THE TAF SITES WITH RDG OF
HI PRES/AXIS OF LLVL DRY AIR DOMINATING. THEN ON SUN...APRCH OF LO
PRES WL BRING SN LOWER CIGS/VSBYS SW-NE TO UPR MI. ALTHOUGH SAW IS
FARTHER TO THE NE...UPSLOPE ESE WIND MIGHT RESULT IN AN EARLIER
ARRIVAL OF THE PCPN/MVFR CIGS. BY LATE IN THE AFTN...CONDITIONS
SHOULD DETERIORATE TO IFR AND POSSIBLY LIFR AT ALL 3 LOCATIONS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 340 PM EST SAT DEC 8 2012
AN AREA OF LOW PRESSURE MOVING OUT OF SOUTHWEST SOUTH DAKOTA WILL
ENTER MN TOMORROW MORNING AND THEN MERGE WITH A LOW DEVELOPING IN
THE GREAT LAKES TO LEAVE A TROUGH OVER NORTHERN WISCONSIN. THIS
TROUGH WILL INCREASE WINDS OUT OF THE EAST AND THEN NORTHEAST
DIRECTION SUNDAY INTO SUNDAY NIGHT. AT THIS TIME...THINKING WINDS
WILL BE IN THE 20-30KT RANGE...ALTHOUGH THERE COULD BE A FEW GALE
FORCE GUSTS TO 35KTS OVER THE WEST AS THE TROUGH SHARPENS LATE
SUNDAY NIGHT. BEHIND THIS FEATURE...A SERIES OF WEAK RIDGES AND
TROUGHS WILL AFFECT LAKE SUPERIOR DURING THE REST OF THE WORK WEEK
AND KEEP WINDS BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 PM SUNDAY TO 7 AM EST MONDAY FOR
MIZ006-007-013-014-085.
WINTER WEATHER ADVISORY FROM 10 AM EST /9 AM CST/ SUNDAY TO 7 AM
EST /6 AM CST/ MONDAY FOR MIZ001-003-004-010-084.
WINTER WEATHER ADVISORY FROM 1 PM SUNDAY TO 1 PM EST MONDAY FOR
MIZ005.
WINTER WEATHER ADVISORY FROM 7 AM EST /6 AM CST/ SUNDAY TO 5 PM
EST /4 PM CST/ MONDAY FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM 9 AM SUNDAY TO 3 AM CST MONDAY FOR
MIZ011-012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...SRF
LONG TERM...TITUS
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
624 PM EST SAT DEC 8 2012
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 340 PM EST SAT DEC 8 2012
HIGH PRESSURE IS CURRENTLY LOCATED IN MANITOBA AND ONTARIO...WITH A
RIDGE STRETCHING SOUTHEAST INTO WESTERN UPPER MI AND WI. LIGHT
NORTHWEST FLOW...WITH RUC ANALYZED H850 OF -10 TO -12C...HAS LED TO
LAKE EFFECT CLOUDS AND LIGHT SNOW SHOWERS THROUGH THIS AFTERNOON IN
THE TRADITIONAL NORTHWEST FLOW LOCATIONS.
UPSTREAM...PV ANOMALY IN SRN SD AND NW NEBRASKA WILL SHIFT ENE
TONIGHT AND INTO MN BY 12Z SUNDAY...WITH THE SURFACE LOW FOLLOWING
SUIT. THIS ANOMALY WILL SHIFT NORTHEAST THROUGH WESTERN UPPER
MICHIGAN THROUGH THE DAY ON SUNDAY AND BE WEAKENING DUE TO INFLUENCE
OF SECOND ANOMALY ENTERING NORTHERN MN AND THE SOUTHERN WAVE
BECOMING MORE DOMINATE AS IT DIVES SOUTHEAST THROUGH THE CENTRAL
ROCKIES DURING THE DAY ON SUNDAY. THIS...COMBINED WITH A
STRENGTHENING JET OVER THE OHIO VALLEY ON SUNDAY...WILL ALLOW A
SECONDARY LOW TO DEVELOP IN THE OHIO VALLEY REGION DURING THE DAY
AND PRODUCE A BROAD AREA OF LOW PRESSURE WHICH TRANSITIONS THE LOW
OVER OUR AREA TO A TROUGH. STILL DIFFERENCES IN THE MODELS...BOTH
RUN-TO-RUN AND BETWEEN MODELS...WITH THE POTENTIAL WEAKENING/SPEED
OF THE PV ANOMALY AND THE LOCATION OF THE ASSOCIATED SURFACE TROUGH
HEADING INTO SUNDAY AFTERNOON/EVENING. LATEST TRENDS IN THE MODELS
ARE FOR A SLOWER MOVEMENT OF THE PV ANOMALY THROUGH UPPER MICHIGAN
ON SUNDAY...WHICH KEEPS THE SURFACE TROUGH AXIS OVER
NORTHERN/CENTRAL WISCONSIN.
TONIGHT...THE HIGH PRESSURE RIDGE EXITING TO THE NORTHEAST WILL
PRODUCE QUIET WEATHER BEFORE THE SYSTEM. UPSTREAM DRYING THIS
AFTERNOON HAS ATE AWAY AT SOME OF THE LAKE EFFECT CLOUDS OVER THE
WEST AND ONCE DAYTIME HEATING IS LOST...EXPECT THE SAME TO OCCUR
OVER THE INTERIOR LOCATIONS THIS EVENING. THIS CLEARING WILL MAKE
FOR TRICKY LOW TEMPERATURES TONIGHT AND FOLLOWED THE PREVIOUS SHIFT
BY TRENDED THEM DOWN A LITTLE MORE AS PWATS 65 PERCENT OF NORMAL
AND THERE ARE LIGHT WINDS. WENT WITH LOWS IN UPPER TEENS...BUT BASED
OFF HOW QUICKLY TEMPS FELL THIS MORNING IN CLEARING AREAS...THAT MAY
NOT BE COLD ENOUGH. OTHERWISE...MID/HIGH LEVEL CLOUDS WILL BE ON THE
INCREASE FROM THE SOUTHWEST WITH THE APPROACHING SYSTEM.
SUNDAY...PRECIPITATION BUILDS IN FROM SOUTHWEST TO NORTHEAST THROUGH
THE DAY. STARTING BETWEEN 12-15Z NEAR KIWD...LATE MORNING OR EARLY
AFTERNOON OVER THE CENTRAL...AND MID/LATE AFTERNOON OVER THE EAST.
WITH THE LATEST SLOWER TRENDS...HAVE DELAYED THE START A COUPLE OF
HOURS FROM THE PREVIOUS SHIFT. PLENTY OF COLD AIR ALOFT...SO EXPECT
PRECIPITATION TO BE AS ALL SNOW. AS FOR FORCING...BEST MID LEVEL WAA
IS FOCUSED OVER THE SOUTH CENTRAL AND NEAR LAKE MICHIGAN THROUGH
THE DAY. THIS LINES UP WITH WEAK FGEN BETWEEN H850-650 OVER THE AREA
FOR THE AFTERNOON...BUT SEEMS TO FOCUS OVER THE SOUTHEAST HALF OF
THE CWA LATE IN THE AFTERNOON. IN ADDITION...BROAD 280-290K
ISENTROPIC ASCENT WILL SPREAD OVER THE CWA DURING THE DAY.
FINALLY...H850 TEMPS AROUND -9C SHOULD FAVOR SOME LAKE ENHANCEMENT
FOR THE KEWEENAW AND ALSO FOR LOCATIONS NEAR LAKE MICHIGAN FAVORED
BY ESE WINDS.
WITH THE SLIGHT DELAY WITH THE SLOWER ARRIVAL OF THE PV ANOMALY AND
SURFACE TROUGH BEING A LITTLE FARTHER SOUTH...BEST PRECIPITATION
STRADDLES THE SHORT/LONG TERM TRANSITION. ALL IN ALL...MODEL QPF
FOR SUNDAY INTO SUNDAY NIGHT WITH THE SYNOPTIC FEATURES IS IN THE
0.25-0.4IN FOR MOST AREAS AND WHEN COMBINED WITH A SNOW RATIO AROUND
13-15 TO 1...WOULD PUT 3 TO 6 INCHES OF SYNOPTIC SNOW OVER THE
AREA THROUGH SUNDAY EVENING. OUTSIDE OF ANY LAKE ENHANCEMENT...THE
HIGHEST AMOUNTS SHOULD LINE UP ALONG THE WISCONSIN BORDER WITH THE
SLIGHT SOUTH SHIFT OF THE SURFACE TROUGH. THE LONG TERM DISCUSSION
WILL COVER THE BULK OF THE HEADLINES...BUT DID DROP THE WATCH OVER
THE WESTERN COUNTIES AND HAVE STARTED A LONGER PERIOD ADVISORY FROM
WEST TO EAST THROUGH THE DAY ON SUNDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 PM EST SAT DEC 8 2012
MAIN CONCERN IS WITH SNOWFALL FORECAST FOR THE FIRST 24 HOURS OF THE
LONG TERM.
SUN NIGHT/MON...IN GENERAL...MODELS ARE IN GOOD AGREEMENT...BUT
THERE ARE SUBTLE VARIATIONS AT SMALLER SCALES THAT BECOME MAGNIFIED
IN THE SNOWFALL FORECAST. THE DIFFICULTY AND UNCERTAINTY IS DUE TO
THE FACT THAT THE SYSTEM OVER THE REGION SUN NIGHT WILL BE MERGING
WITH A SRN STREAM SYSTEM OVER THE OHIO VALLEY...PLUS THE FACT THAT
MODELS HAVE A HARD TIME CONSISTENTLY HANDLING THE PV ANOMALIES THAT
WILL DRIVE A GOOD PORTS OF THE SNOWFALL WITH THIS SYSTEM. LATEST
RUNS OF THE GFS/NAM/REGIONAL GEM/REGIONAL WRF ARE NOW IN BETTER
AGREEMENT IN BRINGING THE WEAKENING PRIMARY PV ANOMALY FROM NW WI AT
00Z MON TO CENTRAL UPPER MI AROUND 06Z MON...THEN SHEARING IT OUT
AND PUSHING IT NORTHEAST BY 12Z MON. MEANWHILE...THE SECONDARY PV
ANOMALY WILL ROTATE INTO CENTRAL/SRN WI...FARTHER S THAN PREVIOUS
RUNS OF THE MODELS. THE TIMING/LOCATION OF THE PV ANOMALIES IS
CONSISTENT WITH THE OVERALL TREND OVER THE LAST FEW RUNS OF THE
MODELS IN SLOWING THE SYSTEM DOWN AND MOVING IT FARTHER S. THE
RESULTING SFC TROUGH LOOKS TO STAY TO THE S OF THE CWA OVER
CENTRAL/NRN WI. LOW LEVEL FLOW WILL GENERALLY BE ELY AT 00Z MON WITH
850MB TEMPS AROUND -9C. BY 06Z MON...LOW LEVEL WINDS BACK TO MORE
ENE...THEN TO NNE BY 12Z MON AS 850MB TEMPS FALL TO -11C. SYNOPTIC
SNOWFALL AMOUNTS WILL BE HIGHEST OVER THE SRN HALF OF UPPER MI SUN
NIGHT...BUT THAT SHOULD BE OFFSET SOME BY UPSLOPE FLOW IN SOME NRN
LOCATIONS...PARTICULARLY NCENTRAL UPPER MI AND THE KEWEENAW...THEN
OVER THE WRN U.P. LATER SUN NIGHT. 850MB TEMPS FALL ANOTHER COUPLE
OF DEGREES THROUGH THE DAY MON WHILE FLOW BECOMES INCREASING
ANTICYCLONIC AS THE SFC TROUGH MOVES QUICKLY E AND A RIDGE MOVES
OVER WRN LAKE SUPERIOR BY 00Z TUE. THUS...EXPECT LES FROM NNW WINDS
MON MORNING...DIMINISHING THROUGH MON EVENING. WITH THIS TYPE OF
SYSTEM THERE IS INHERENT UNCERTAINTY THAT WILL PROBABLY NOT BE
RESOLVED UNTIL THE SYSTEM IS ON THE DOORSTEP OF THE CWA...SO
CONFIDENCE IN SNOWFALL AMOUNTS IS STILL SOMEWHAT LIMITED. STORM
TOTAL SNOWFALL AMOUNTS OF 3 TO 6 INCHES IS EXPECTED...WITH SOME
LOCALLY HIGHER AMOUNTS POSSIBLE IN THE HIGHER TERRAIN OF WRN
GOGEBIC/ONTONAGON COUNTIES AND NW MARQUETTE/NE BARAGA COUNTIES.
DECIDED IN COORDINATION WITH SHORT TERM SHIFT TO ISSUE WINTER WX
ADVISORIES OVER THE ENTIRE CWA. COULD SEE SOME LOCATIONS GO SLIGHTLY
ABOVE ADVISORY CRITERIA...BUT NOT CONFIDENT ENOUGH IN THAT TO
JUSTIFY WARNING. ALSO...THE TIME THAT THE HEAVIEST SNOW WILL FALL
/SUN EVENING AND EARLY SUN NIGHT/ IS NOT A HIGH IMPACT TIME TRAVEL
WISE...PLUS THE FACT THAT THE STORM TOTAL WILL OCCUR OVER 24 HOURS
OR MORE. ALSO DECIDED ON THE ADVISORY WITH THE IDEA THAT IT WOULD BE
EASIER TO UPGRADE TO A WARNING IF NEEDED THAN HAVE TO CANCEL
WARNINGS AND ISSUE AN ADVISORY IF THE BORDERLINE WARNING AMOUNTS DO
NOT OCCUR...WHICH WOULD LEAD TO A MISSED EVENT FOR
VERIFICATION...SORT OF THE PATH OF LEAST REGRET.
A VERY WEAK SHORTWAVE TROUGH MOVES ACROSS THE AREA TUE INTO TUE
NIGHT...BRINGING SE FLOW OFF LAKE MICHIGAN FROM 12Z TUE INTO WED.
THIS SHOULD LEAD TO LES OFF LAKE MI INTO ERN UPPER MI...ESPECIALLY
SERN SCHOOLCRAFT COUNTY. INVERSION HEIGHTS SHOULD BE AROUND 10KFT
ACCORDING TO THE NAM/GFS WITH UNIDIRECTIONAL WINDS. THE RESULTING
LES BAND SHOULD BE A LARGER MORE DOMINANT ONE...BUT SHOULD ALSO NOT
STAY IN ONE PLACE TOO LONG AS WINDS STEADILY VEER. EVEN SO...MAY END
UP BEING CLOSE TO ADVISORY AMOUNTS. WINDS WILL BECOME WLY ENOUGH
BEHIND THE TROUGH BY 06Z WED TO BRING LES TO NW UPPER MI...BUT WINDS
QUICKLY BECOME ANTICYCLONIC BY 12Z WED AS A SFC RIDGE MOVES TO WRN
LAKE SUPERIOR...SO LIGHTER SNOW AMOUNTS ARE EXPECTED THERE.
A SLIGHTLY STRONGER SYSTEM WILL MOVE N OF THE AREA THU AND DRAW
WARMER TEMPS IN THE CWA...BUT NO SIGNIFICANT PRECIP IS EXPECTED.
HIGHS IN THE MID TO UPPER 30S SEEMS REASONABLE. PRETTY QUIET AFTER
THAT UNTIL MODELS INDICATE A MUCH STRONGER LOW PRESSURE SYSTEM
MOVING NEARBY ON SAT. MODELS ARE IN GOOD AGREEMENT FOR HOW FAR OUT
THE SYSTEM IS...SO WILL USE CONSENSUS OF MODELS FOR THE FORECAST
PAST TUE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 622 PM EST SAT DEC 8 2012
ALTHOUGH SOME INTERVALS OF MVFR CIGS ARE POSSIBLE TNGT...EXPECT
PREDOMINANT VFR CONDITIONS THRU 12Z AT ALL THE TAF SITES WITH RDG OF
HI PRES/AXIS OF LLVL DRY AIR DOMINATING. THEN ON SUN...APRCH OF LO
PRES WL BRING SN LOWER CIGS/VSBYS SW-NE TO UPR MI. ALTHOUGH SAW IS
FARTHER TO THE NE...UPSLOPE ESE WIND MIGHT RESULT IN AN EARLIER
ARRIVAL OF THE PCPN/MVFR CIGS. BY LATE IN THE AFTN...CONDITIONS
SHOULD DETERIORATE TO IFR AND POSSIBLY LIFR AT ALL 3 LOCATIONS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 340 PM EST SAT DEC 8 2012
AN AREA OF LOW PRESSURE MOVING OUT OF SOUTHWEST SOUTH DAKOTA WILL
ENTER MN TOMORROW MORNING AND THEN MERGE WITH A LOW DEVELOPING IN
THE GREAT LAKES TO LEAVE A TROUGH OVER NORTHERN WISCONSIN. THIS
TROUGH WILL INCREASE WINDS OUT OF THE EAST AND THEN NORTHEAST
DIRECTION SUNDAY INTO SUNDAY NIGHT. AT THIS TIME...THINKING WINDS
WILL BE IN THE 20-30KT RANGE...ALTHOUGH THERE COULD BE A FEW GALE
FORCE GUSTS TO 35KTS OVER THE WEST AS THE TROUGH SHARPENS LATE
SUNDAY NIGHT. BEHIND THIS FEATURE...A SERIES OF WEAK RIDGES AND
TROUGHS WILL AFFECT LAKE SUPERIOR DURING THE REST OF THE WORK WEEK
AND KEEP WINDS BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 PM SUNDAY TO 7 AM EST MONDAY FOR
MIZ006-007-013-014-085.
WINTER WEATHER ADVISORY FROM 10 AM EST /9 AM CST/ SUNDAY TO 7 AM
EST /6 AM CST/ MONDAY FOR MIZ001-003-004-010-084.
WINTER WEATHER ADVISORY FROM 1 PM SUNDAY TO 1 PM EST MONDAY FOR
MIZ005.
WINTER WEATHER ADVISORY FROM 7 AM EST /6 AM CST/ SUNDAY TO 5 PM
EST /4 PM CST/ MONDAY FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM 9 AM SUNDAY TO 3 AM CST MONDAY FOR
MIZ011-012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...TITUS
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
646 PM CST SAT DEC 8 2012
.UPDATE...
00Z AVIATION DISCUSSION ADDED BELOW.
&&
.PREV DISCUSSION...
/ISSUED 447 PM CST SAT DEC 8 2012/
..DANGEROUS WINTER STORM TO IMPACT THE UPPER MISSISSIPPI VALLEY
TONIGHT THROUGH SUNDAY NIGHT...
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT.
LOW PRESSURE LOCATED NEAR VALENTINE NEBRASKA LATE THIS AFTERNOON WILL
TRACK ALMOST DUE EAST TONIGHT AND SUNDAY...TRACKING ROUGHLY ALONG
THE I-90 CORRIDOR. THIS IS A SIGNIFICANT SHIFT SOUTH FROM WHAT
MODELS WERE SHOWING YESTERDAY...WITH THE NAM REMAINING THE LONE
NORTHERN OUTLIER TRACKING IT ACROSS THE TWIN CITIES METRO. IN
ADDITION...QPF HAS INCREASED MARKEDLY FROM 00Z RUNS AND NOW
AVERAGES BETWEEN A HALF AND AT LEAST THREE QUARTERS OF AN INCH
FROM WILLMAR TO NEAR LADYSMITH...OR JUST NORTH OF THE METRO.
ELSEWHERE...QPF AVERAGES 0.3 TO 0.5 INCHES. THE 18Z GFS IS COMING
IN SURPRISINGLY HIGH AT NEARLY ONE INCH AND AGAIN JUST A BIT FURTHER
SOUTH FROM PREVIOUS RUNS...NOW THROUGH THE METRO. EVEN THE EC WHICH
WAS THE DRY OUTLIER YESTERDAY IS SHOWING AT LEAST 0.6 INCHES OVER
MUCH OF THE CENTRAL AREAS. MODEL INCONSISTENCY FROM RUN TO RUN
SHOULD NOW BE ABOUT COMPLETE...LEAVING A VERY HIGH PROBABILITY
FOR A MAJOR WINTER STORM ACROSS MUCH OF THE AREA TONIGHT INTO
SUNDAY EVENING.
THE ARC OF SNOW EXPECTED TO PROPAGATE INTO WESTERN MINNESOTA DURING
THE NEXT FEW HOURS IS EXPANDING IN SIZE AND PRODUCING MODERATE TO
HEAVY SNOWFALL RATES WITHIN EMBEDDED BANDS. WITH TIME...THIS AREA
OF SNOW WILL EXPAND WITH WIDESPREAD MODERATE TO HEAVY SNOW
EXPECTED TO SPREAD EAST ACROSS THE AREA LATER THIS EVENING AND
OVERNIGHT. FRONTOGENESIS WITHIN THE DENDRITIC GROWTH ZONE IS
RATHER IMPRESSIVE SO EMBEDDED BANDS OF VERY HEAVY SNOW WITH
GREATER THAN ONE INCH HOURLY RATES ARE POSSIBLE THROUGH SUNDAY
MORNING. BECAUSE THE TRACK OF THE LOW WILL BE CONFINED TO ABOUT
I-90...THE THREAT FOR DRY SLOTTING INTO THE SOUTHERN AREAS IS A
BIT LOWER ALTHOUGH STILL POSSIBLE FOR THE SOUTHERN TWO TIERS OF MN
COUNTIES COME SUNDAY MORNING. STORM TRACK HAS SLOWED A BIT AS
WELL...THUS DEFORMATION SNOW WILL HELP PILE ON THE INCHES A BIT
LONGER THAN ANTICIPATED YESTERDAY. OCCASIONAL SNOW OR SNOW SHOWERS
ARE EXPECTED THROUGH AT LEAST EARLY SUNDAY AFTERNOON AND POSSIBLY
THROUGH THE EVENING OVER WESTERN WISCONSIN.
PREDICTED SNOWFALL AMOUNTS MAY BE CONSERVATIVE IF THE HIGHER QPF
DEPICTIONS PAN OUT...BUT STILL EXPECTING 6 TO 9 INCHES ACROSS
CENTRAL MN AND WESTERN WISCONSIN...AND 3 TO 5 INCHES NEAR THE
IOWA BORDER. COULD SEE SOME ISOLATED TOTALS EXCEED 9 OR 10 INCHES
IN LOCALLY FAVORED BANDING AREAS.
THEREFORE...EXPANDED THE WINTER STORM WARNING SOUTH TO ABOUT A
LINE FROM REDWOOD FALLS...TO RED WING..AND EAU CLAIRE WITH A
WINTER WEATHER ADVISORY SOUTH OF THAT TO THE IOWA BORDER. THESE
HEADLINES DEAL WITH SNOWFALL TOTALS ONLY.
THE BIG CHANGE TO THIS FORECAST PACKAGE WAS TO ISSUE A BLIZZARD
WARNING FROM LATE SUNDAY MORNING THROUGH SUNDAY EVENING WEST OF A
LINE FROM ALEXANDRIA TO WILLMAR AND MANKATO. MODELS HAVE BEEN
CONSISTENT IN SHOWING POTENTIAL FOR 40 KT WINDS WITHIN THE MIXED
LAYER BEHIND THE SYSTEM AND THINK GUSTS TO AT LEAST 35 KTS WILL BE
FREQUENT. COUPLE THAT WITH FRESHLY FALLEN SNOW AND POTENTIALLY
ADDITIONAL LIGHT SNOW...CONFIDENCE HAS INCREASED THAT BLIZZARD
CONDITIONS WILL BE COMMON WITH NEAR ZERO VISIBILITIES IN OPEN
AREAS SUNDAY AFTERNOON AND EARLY EVENING /ESPECIALLY IF GUSTS
EXCEED 45 MPH/. TEMPERATURES WILL PLUMMET BELOW ZERO SUNDAY
EVENING AS WELL...THREATENING THE LIVES OF ANY STUCK TRAVELERS.
KEPT THE BLIZZARD WARNING CONFINED TO AREAS WITH A HIGH
LIKELIHOOD OF AT LEAST 4 INCHES OF SNOW WHICH IS GENERALLY NEEDED
FOR CONSIDERABLE BLOWING AND DRIFTING.
THE SYSTEM WILL PULL OUT SUNDAY NIGHT AS THE RIDGE QUICKLY BUILDS
INTO THE WEST. SOME SNOW IS STILL POSSIBLE OVER WRN WI IN CYCLONIC
FLOW...BUT CLEARING SKIES WILL ALLOW FOR A BITTER COLD NIGHT WITH
LOWS IN THE TEENS BELOW OVER WRN MN AND NEAR ZERO AS FAR EAST AS
I-35. WINDS SHOULD REMAIN ELEVATED ENOUGH TO BRING WIND CHILL
VALUES DOWN INTO THE 20S AND POSSIBLY LOW 30S BELOW NEAR THE SOUTH
DAKOTA BORDER...WITH TEENS BELOW TO I-35. WIND CHILL ADVISORIES
WILL BE NEEDED AFTER THE OTHER WINTER HEADLINES EXPIRE.
WILL REMAIN COLD DESPITE SUNSHINE ON MONDAY UNDER THE RIDGE
AXIS...BUT RETURN FLOW MONDAY EVENING SHOULD KEEP TEMPS STEADY OR
SLOWLY RISE OVERNIGHT. A WEAK SYSTEM PASSING THROUGH THE UPPER
MISSISSIPPI VALLEY TUESDAY COULD BRING A LITTLE LIGHT SNOW OR
FLURRIES WITH NO ACCUMULATIONS ARE EXPECTED.
LONG TERM...WEDNESDAY THROUGH SATURDAY.
UPPER LEVEL RIDGING WILL BE IN PLACE ACROSS THE GULF OF ALASKA BY
MIDWEEK...WITH A DEEP TROUGH DIGGING DOWN THE WEST COAST.
SOUTHWEST FLOW WILL STREAM ACROSS THE CENTRAL CONUS...WITH WARM
AIR ADVECTION SPREADING OVERHEAD ALLOWING HIGH TEMPS TO MAKE A RUN
AT THE THAWING MARK FOR BOTH WEDNESDAY AND THURSDAY. BY FRIDAY A
WELL ESTABLISHED EAST/WEST TEMPERATURE GRADIENT WILL BE IN PLACE
OVER THE UPPER MIDWEST...AND THE AFOREMENTIONED WEST COAST TROUGH
WILL MOVE INLAND OVER THE FOUR CORNERS REGION. THIS WILL BE THE
MAIN PLAYER IN THE WEEKEND WEATHER AS BOTH THE GFS AND ECMWF 08.12
EJECT THIS WAVE TOWARDS THE GREAT LAKES REGION. THIS PV ANOMALY
WILL ACT ON THE LOW LEVEL TEMPERATURE GRADIENT AND CAUSE A SURFACE
CYCLONE TO DEVELOP AND TRACK SOUTH AND EAST OF THE CWA. THIS WOULD
PUT CENTRAL MINNESOTA AND WESTERN WISCONSIN IN A FAVORABLE REGION
FOR ANOTHER POTENTIAL WEEKEND SNOW STORM. FORECAST SOUNDINGS AND
NORTH/SOUTH CROSS SECTIONS VIA THE GFS SHOW A WARM LAYER CENTERED
AROUND H850 WITH THE 0C LINE EXTENDING AS FAR NORTH AS THE METRO
AREA. THEREFORE HAVE INCLUDED THE CHANCE OF MIXED PRECIP FOR
SATURDAY MORNING ACROSS THE SOUTHEAST HALF OF THE CWA WITH THE
INITIAL SURGE OF LOW LEVEL THETA_E ADVECTION...AND THEN TRANSITION
TO ALL SNOW BY THE AFTERNOON. ALSO INCREASED POPS ABOVE GUIDANCE
GIVEN THE REMARKABLE AGREEMENT BY THE LONG RANGE MODELS.
&&
.AVIATION.../06Z TAF ISSUANCE/
WINTER STORM STILL ON TRACK TO IMPACT ALL TERMINALS THIS
PERIOD...WITH VERY POOR WEATHER CONDITIONS EXPECTED. TIMED SNOW IN
BASED ON THE LOCAL WRF AND HIRES-ARW FORECAST...WHICH RESULTED IN
A SLIGHT DELAY IN SNOW ONSET. LOOKING AT OBS IN SODAK...WITHIN AN
HOUR OF ONSET OF SNOW...VIS WILL DROP TO 1/2SM OR LESS...SO
QUICKLY DROPPED CONDITIONS IN TAFS. THE RAP SHOWS HOURLY SNOWFALL
ACCUMS OF AN 1"+ PER HOUR TONIGHT INTO THE MORNING...AND IF THIS
IS TO BE THE CASE...THEN PERIODS OF 1/4SM OR LESS VIS IN HEAVY
SNOW WILL BE LIKELY WITHIN PERIOD WHERE 1/2SM PREVAILING CONDS ARE
MENTIONED. SFC LOW NOW SOUTH OF PIERRE...AND BY THE AFTERNOON IT
SHOULD BE PASSING VERY NEAR MSP. EXPECT HEAVIEST SNOW OUT AHEAD OF
THE LOW...WITH DEFORMATION BAND PROLONGING REDUCED CONDITIONS AT
AXN/STC. SNOW TOTALS AT ALL TERMINALS LOOKS TO BE IN THE 5 TO 8
INCH RANGE. FOR WINDS...STRONG CAA LOOKS TO PROMOTE GUSTS WELL
OVER 30KTS AT AXN/RWF AFTER 18Z...WHICH WILL LEAD TO REDUCED VSBY
ISSUES WITH BLSN THERE. CONFIDENCE DOES DECREASE DURING THE DAY
TOMORROW...WITH PRIMARY AMOUNT OF TIME SPENT PINNING DOWN TIMING
OF THE ONSET OF SN.
KMSP...SIGNIFICANT IMPACTS EXPECTED WITH WINTER STORM THIS
PERIOD. IN ALL LIKELIHOOD...SNOW RATES WILL BE IN EXCESS OF 3/4 OF
AN INCH AN HOUR...SO AN AWW WILL BE NEEDED AT SOME POINT AROUND
6Z. AS SFC LOW NEARS THE FIELD...MAY SEE A WINDOW BETWEEN 15Z AND
20Z WHERE SNOW CUTS OFF AND VIS INCREASES...BEFORE WRAP AROUND
SNOW AND STRONG NW WINDS SEND VIS BACK DOWN IN -SN AND BLSN.
/OUTLOOK FOR KMSP/
MON...MVFR/IFR CIGS POSSIBLE EARLY. THEN VFR. WINDS WNW AT 10G15KTS.
TUE...MVFR/IFR CIGS POSSIBLE. WINDS SW AT 10G15KTS.
WED...VFR. WINDS SE AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST
SUNDAY NIGHT FOR BLUE EARTH-FARIBAULT-FREEBORN-GOODHUE-LE
SUEUR-RICE-STEELE-WASECA.
WINTER STORM WARNING UNTIL 11 AM CST SUNDAY FOR CHIPPEWA-DOUGLAS-
KANDIYOHI-LAC QUI PARLE-POPE-RENVILLE-SIBLEY-STEVENS-SWIFT-
YELLOW MEDICINE.
BLIZZARD WARNING FROM 11 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT
FOR BROWN-CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-NICOLLET-
POPE-REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE.
WINTER STORM WARNING UNTIL MIDNIGHT CST SUNDAY NIGHT FOR BENTON-
CHISAGO-ISANTI-KANABEC-MCLEOD-MEEKER-MILLE LACS-MORRISON-
SHERBURNE-STEARNS-TODD-WRIGHT.
WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO MIDNIGHT CST
SUNDAY NIGHT FOR ANOKA-CARVER-DAKOTA-HENNEPIN-RAMSEY-SCOTT-
WASHINGTON.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST SUNDAY NIGHT FOR
MARTIN-WATONWAN.
WINTER WEATHER ADVISORY UNTIL 11 AM CST SUNDAY FOR BROWN-
NICOLLET-REDWOOD.
WI...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO MIDNIGHT CST
SUNDAY NIGHT FOR BARRON-CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-
PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
BORGHOFF/MPG
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 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
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...UPDATED
NWS ST LOUIS MO
850 PM CST SAT DEC 8 2012
.UPDATE...
ISSUED AT 849 PM CST SAT DEC 8 2012
MUCH OF THE CWA HAS BEEN DRY SO FAR THIS EVENING WITH LOW CLOUDS
AND SOME PATCHY FOG. STILL BELIEVE THAT RAIN CHANCES WILL INCREASE
SIGNIFICANTLY LATER THIS EVENING AND OVER NIGHT AS LARGE SCALE
ASCENT INCREASES AHEAD OF SHORTWAVE MOVING ACROSS THE CENTRAL
PLAINS. RAP HAS BEEN CONSISTENT IN SHOWING AN INCREASE IN LOW
LEVEL MOISTURE CONVERGENCE ALONG 850MB WARM FRONT TONIGHT. ONLY
CHANGE IN FORECAST IS TO REFLECT NEAR TERM PRECIPITATION AND
TEMPERATURE TRENDS.
BRITT
&&
.SHORT TERM...
ISSUED AT 213 PM CST SAT DEC 8 2012
(TONIGHT)
SHORTWAVE DIVING THROUGH EASTERN MONTANA AT THIS TIME IS FORCING
CYCLOGENESIS OVER THE NORTHERN PLAINS. SOUTHWESTERLY LOW LEVEL
FLOW WILL BEGIN TO INCREASE OVER THE LOWER MISSISSIPPI VALLEY
TONIGHT IN RESPONSE TO THE STRENGTHENING LOW. THIS WILL BRING THE
QUASI-STATIONARY FRONT HANGING OVER ARKANSAS BACK NORTH INTO OUR
AREA BY EARLY SUNDAY MORNING. LOW LEVEL JET RAMPS UP AROUND 30KTS
THIS EVENING PRODUCING DECENT 850MB MOISTURE CONVERGENCE OVER THE
AREA. AT FIRST IT`S RATHER WEAK AND DIFFUSE...BUT BECOMES STRONGER
OVER NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS LATE TONIGHT AS
THE 850MB TEMP GRADIENT TIGHTENS UP. EXPECT WIDELY SCATTERED
SHOWERS TO DEVELOP THIS EVENING OVER SOUTHEAST
MISSOURI...OVERSPREADING THE ENTIRE AREA AND INCREASING IN AREAL
COVERAGE IN RESPONSE TO THE INCREASING MOISTURE CONVERGENCE. COULD
SEE A LITTLE THUNDER AS WELL...PRIMARILY OVER SOUTHEAST MISSOURI
AND SOUTHERN ILLINOIS WHERE MUCAPE IS FORECAST TO EXCEED 250 J/KG.
TEMPERATURES WILL TAKE AN INITIAL DIP THIS EVENING...BUT SHOULD
LEVEL OUT AND POSSIBLY RISE SLIGHTLY AS THE WARM FRONT MOVES UP
INTO THE BI-STATE REGION LATE TONIGHT.
CARNEY
&&
.LONG TERM...
ISSUED AT 213 PM CST SAT DEC 8 2012
SUNDAY AND SUNDAY NIGHT...
THE WARM FRONTAL BOUNDARY WILL BE LOCATED ACROSS THE SOUTHERN
PORTION OF THE CWA BY 12Z...WITH THE OVERNIGHT WARM ADVECTION
PRECIPITATION BEGINNING TO LIFT NORTH AND EAST OF THE CWA. THINK
THERE WILL BE A LULL IN THE RAIN BY MIDMORNING ACROSS A GOOD AMOUNT
OF THE CWA UNTIL A STRONG COLD FRONT MOVES SOUTHEAST ACROSS THE AREA
IN THE AFTERNOON AND EVENING. THIS FRONT WILL REINFORCE THE
BAROCLINICITY TO OUR SOUTHEAST AND LEAD TO LIGHT RAIN REDEVELOPING
ACROSS AT LEAST THE SOUTHEAST HALF OF THE CWA FOR THE AFTERNOON AND
EARLY EVENING HOURS. LUCKILY...ALL INDICATIONS ARE THAT THE RAIN
WILL TURN TO COLD SUNDAY NIGHT AS DEEP MOISTURE IS SHUNTED TO THE
SOUTHEAST AS THE WINTER BLAST ARRIVES AND COLD AIR DEEPENS ACROSS
THE CWA.
MONDAY THROUGH THURSDAY...
A RAW WINTER DAY IS ON TAP FOR MONDAY AS TEMPERATURES STRUGGLE TO
RISE BACK ABOVE FREEZING WITH STRONG COLD ADVECTION AND A GUSTY
NORTHWEST WIND. THE WINTER CHILL SHOULD BE BRIEF THOUGH...AS
TEMPERATURES WILL ALREADY BEGIN MODERATING BY MIDWEEK DESPITE A TROF
MOVING ACROSS THE MIDWEST. TEMPERATURES WILL RISE BACK ABOVE NORMAL
FOR THE END OF THE WEEK AS THE UPPER FLOW BECOMES SOUTHWEST IN
RESPONSE TO A STRONG STORM SYSTEM DIGGING SOUTH ALONG THE WEST COAST.
FRIDAY THROUGH SATURDAY...
NEARLY ALL OF THE MEDIUM RANGE GUIDANCE DEPICTS A STRONG SHORTWAVE
AND SURFACE LOW PASSING TO THE WEST OF THE CWA FRIDAY NIGHT. THIS
PATTERN IS INDICATIVE OF ABOVE NORMAL TEMPERATURES AND A GOOD CHANCE
OF SHOWERS AND THUNDERSTORMS.
CVKING
&&
.AVIATION...
ISSUED AT 541 PM CST SAT DEC 8 2012
STRATUS CLOUDS AROUND 1500 FT WILL GRADUALLY LOWER TGT ALONG WITH
THE DEVELOPMENT OF FOG. LIGHT RAIN WILL ALSO MOVE BACK INTO THE
AREA LATE TGT AS THE STATIONARY FRONT ACROSS NRN AR LIFTS BACK NWD
INTO SRN MO AND A SWLY LOW LEVEL JET BRINGS INCREASING AND
DEEPENING LOW LEVEL MOISTURE INTO THE AREA. CEILINGS WILL LIKELY
LOWER TO AROUND 500 FT WITH VSBYS OF 1-3SM IN LIGHT RAIN AND FOG.
THE E-NELY SFC WIND WILL GRADUALLY VEER AROUND TO AN E-SELY
DIRECTION. THE RAIN SHOULD END IN UIN AND COU BY LATE SUN MRNG AS
A SFC WAVE ALONG THE FRONT MOVES E OF THE AREA...WHILE A STRONG
COLD FRONT DROPS SEWD INTO THE REGION. RAIN WILL LIKELY CONTINUE
IN THE ST LOUIS METRO AREA SUN AFTN UNTIL THE COLD FRONT MOVES SE
OF THE AREA WITH CAA AND DRYING OF THE LOW LEVELS BEHIND THE COLD
FRONT. THE SFC WIND WILL VEER AROUND TO A NWLY DIRECTION AS THE
SFC WAVE SHIFTS E OF THE AREA...AND THEN STRENGTHENS AFTER
PASSAGE OF THE STRONG COLD FRONT SUN AFTN. WILL SEE AN IMPROVEMENT
IN VSBYS LATE SUN MRNG AND AFTN...BUT ONLY A VERY GRADUAL RISE IN
CEILING HEIGHTS WITH CIGS RISING TO AROUND 1000 FT BY EARLY AFTN.
SPECIFICS FOR KSTL...CIG HEIGHTS SHOULD LOWER LATER THIS EVNG WITH
FOG DEVELOPING. THE CIGS SHOULD LOWER TO AROUND 500 FT LATE TGT
WITH VSBYS FALLING TO AROUND 2SM AS LIGHT RAIN MOVES INTO THE
AREA. THE NELY SFC WIND WILL GRADUALLY VEER AROUND TO AN ELY
DIRECTION LATER THIS EVNG...AND A SELY DIRECTION LATE TGT AS A
SFC RIDGE SHIFTS WELL NE OF OUR AREA WHILE A WARM FRONT APPROACHES
STL FROM THE S. THE RAIN SHOULD END BY SUN EVNG AS A SFC WAVE
ALONG THIS FRONT SHIFTS WELL NE OF STL AND A STRONG COLD FRONT
MOVES SE OF STL CAUSING THE SFC WIND TO VEER AROUND TO A W-NWLY
DIRECTION AND STRENGTHEN DURING THE AFTN AND EVNG HOURS. THE VSBYS
WILL IMPROVE DURING THE LATE MRNG AND AFTN HOURS WITH THE CLOUD CEILING
RISING TO AROUND 1000 FT BY AFTN AND 1500 FT BY SUN EVNG.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
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 NORTH PLATTE NE
606 PM CST SAT DEC 8 2012
.AVIATION...FOR THE KLBF AND KVTN TERMINALS THROUGH 00Z MONDAY.
AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL TRACK ACROSS THE CENTRAL
AND NORTHERN PLAINS OVER THE NEXT 24 HOURS...LEADING TO ABUNDANT
CLOUDINESS AND WINDY CONDITIONS ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA. AT THE KLBF TERMINAL...EXPECT CIGS AON 10000 FT AGL
THROUGH 10Z TONIGHT...DROPPING DOWN TO AROUND 4000 FT AGL. CIGS WILL
BEGIN TO SCATTER OUT AFTER 17Z SATURDAY. AT THE KVTN TERMINAL...CIGS
WILL DROP FROM 5000 FT AGL DOWN TO 1500 FT AGL OVERNIGHT AND REMAIN
THERE THROUGH MIDDAY SUNDAY. SKIES WILL BEGIN TO SCATTER OUT BY LATE
AFTERNOON. FOR BOTH TERMINALS...LOOK FOR NORTHERLY WINDS TO INCREASE
TO 15 TO 25 KTS TONIGHT WITH PERIODIC GUSTS TO AROUND 30 KTS AT BOTH
TERMINALS. WINDS WILL GRADUALLY DIMINISH LATE SUNDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 244 PM CST SAT DEC 8 2012/
...MUCH COLDER WITH WINDY CONDITIONS LATE TONIGHT AND SUNDAY...
SYNOPSIS... SURFACE LOW PRESSURE RESIDES ACROSS THE CENTRAL HIGH
PLAINS WITH MAIN LOW FORMING NEAR PINE RIDGE SOUTH DAKOTA. LEADING
EDGE OF COLD FRONT JUST PASSED CHADRON. STEEP LAPSE RATES
ATTRIBUTING TO CONVECTIVE SNOW SHOWERS PANHANDLE INTO NORTH
CENTRAL. MUCH OF RADAR ECHOES NOT REACHING GROUND EFFECTIVELY DUE
TO FAIRLY LARGE TEMPERATURES AND DEWPOINT SPREAD. NEVERTHELESS...
THIS HAS BEEN MOISTENING UP THE ATMOSPHERE FOR UPSTREAM
DEVELOPMENT TO TAKE ADVANTAGE OF FOR LATE AFTERNOON INTO THIS
EVENING.
DISCUSSION...
SHORT TERM...TONIGHT THROUGH TUESDAY. MAIN FORECAST CONCERNS OVER
THE NEXT 36 HOURS INVOLVES THE THREAT OF LIGHT SNOW...A RETURN OF
COLD TEMPERATURES...AND THE POTENTIAL OF ADVISORY CRITERIA WIND
SPEEDS.
MODELS CONTINUE TO SHOW GOOD AGREEMENT IN THE NEAR TERM IN WHICH THE
SHORTWAVE TROUGH CURRENTLY LOCATED FROM CENTRAL SOUTH DAKOTA INTO
EASTERN MONTANA AND ASSOCIATED SURFACE LOW DEEPEN AND EJECT EAST
ACROSS THE NORTHERN PLAINS...DRAGGING A STRONG COLD FRONT THROUGH
THE CWA OVERNIGHT TONIGHT. THE RAP MODEL CONTINUES TO INDICATE THE
SURFACE LOW NEAR AND SOUTH OF I90 TONIGHT WHICH REMAINS FARTHER SOUTH
THAN OTHER SHORT TERM MODELS. AN H3 JET MAX ACROSS NORTHERN
COLORADO AND SOUTHERN NEBRASKA THIS EVENING WILL BE FAVORABLE FOR
ASCENT IN THE LEFT EXIT REGION OF JET ACROSS NORTH CENTRAL
NEBRASKA. AS SUGGESTED BY THE RAP MODEL...REGIONAL GEM AND TO A
LESSER EXTEND THE NAM...BANDED SNOWFALL IS FAVORABLE FROM NEAR
MULLEN THROUGH BASSETT. LOCAL SNOWFALL AMOUNTS NEAR AN INCH
POSSIBLE IN THESE BANDED AREAS. OTHERWISE...LIGHT SNOW ALSO
FORECAST TO DEVELOP AND DROP SOUTH INTO FAR NORTHERN NEBRASKA LATE
TONIGHT INTO SUNDAY MORNING. THIS IS WITHIN SOUTHERN PERIPHERY OF
DEFORMATION ZONE TO BE ACROSS EASTERN SOUTH DAKOTA INTO SOUTH
CENTRAL SOUTH DAKOTA. ANY ASSOCIATED SNOWFALL WOULD REMAIN A HALF
INCH OR LESS. ACROSS THE SOUTHERN HALF OF FORECAST AREA...ANY
LINGERING SNOW OR FLURRIES FROM THIS EVENING SHOULD END SOON
AFTER MIDNIGHT.
STRONG COLD AIR ADVECTION AND LOW LEVEL PRESSURE RISES WILL
FOLLOW THE SURFACE BOUNDARY PASSAGE OVERNIGHT TONIGHT. THE
PRESSURE RISES WILL HELP TIGHTEN THE SURFACE GRADIENT AND ALLOW
FOR GUSTY CONDITIONS LATER TONIGHT INTO SUNDAY. THE MODELS HAVE
SHOWN A SLIGHT SOUTHWARD TREND IN THE TRACK OF THE SURFACE
LOW...NOW ACROSS FAR SOUTHWEST MINNESOTA. THIS TRACK FAVORS
SLIGHTLY STRONGER SURFACE WINDS THAN PREVIOUSLY ANTICIPATED. WILL
KEEP WIND SPEEDS JUST BELOW ADVISORY CRITERIA...ESPECIALLY SINCE
THE STRONGEST PRESSURE RISES ARE EXPECTED DURING THE EARLY MORNING
HOURS...DIURNALLY UNFAVORABLE FOR ADVISORY CRITERIA WIND.
BUT...WIDESPREAD SUB ZERO WIND CHILLS WILL OCCUR...WITH THE
POTENTIAL OF SOME OF THE LOWEST READINGS APPROACHING MINUS TEN OR
COLDER THROUGH SUNDAY MORNING ACROSS OUR NORTHERN ZONES. HIGHS ON
SUNDAY WILL BE COLD...WITH READINGS TRENDED DOWN TO NEAR 15 AT
VALENTINE TO THE MID 20S FAR SOUTH. WE WILL NEED TO WATCH LOW
TEMPERATURES FOR MONDAY MORNING...AS ANY SNOWFALL WOULD ALLOW
READINGS TO PLUMMET...TO POSSIBLY BELOW ZERO. CURRENT FORECAST HAS
LOWS 1 TO 5 ABOVE MOST AREAS...AS WIDESPREAD ACCUMULATING SNOW IS
NOT ANTICIPATED. TEMPERATURES BEGIN TO MODERATE SLOWLY MONDAY
AFTERNOON AS WEAK WAA INFILTRATES FROM THE WEST IN ADVANCE OF THE
NEXT SHORTWAVE TROUGH. HIGHS TO RANGE IN THE 30S. THEN A WESTERLY
DOWNSLOPE TUESDAY TO WARM READINGS TO THE MID 30S TO LOWER 40S.
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY. SHORTWAVE RIDGING AND
WAA TAKE HOLD WEDNESDAY THROUGH THURSDAY...WITH TEMPERATURES SLIGHTLY
ABOVE SEASONAL NORMS WEDNESDAY AND NEAR NORMAL THURSDAY. WILL NEED
TO MONITOR IF A BACK DOOR COLD FRONT DROPS INTO NORTH CENTRAL
NEBRASKA THURSDAY. THE ECMWF AND GEM KEEP COLDER AIR TO THE NORTH
INTO SOUTH DAKOTA...WHILE THE GFS BRINGS IT SOUTH INTO NORTHERN
NEBRASKA. THE NEXT SIGNIFICANT TROUGH IS SHOWN TO REACH THE FOUR
CORNERS REGION 12Z FRIDAY AND TRACK INTO NORTHWEST MISSOURI AS A
NEGATIVELY TILTED CLOSED LOW BY 12Z SATURDAY PER THE ECMWF
SOLUTION. THE GFS ALSO INDICATES A NEGATIVELY TILTED
TROUGH...ALTHOUGH AS AN OPEN WAVE FROM WESTERN SOUTH DAKOTA INTO
NORTHERN NEBRASKA. PRECIPITATION CHANCES NOW BROUGHT INTO EASTERN
NEBRASKA FRIDAY NIGHT INCLUDING FAR EASTERN PORTIONS OF NORTH
CENTRAL NEBRASKA. HIGHS FRIDAY FORECAST TO RANGE IN THE 30S AND
MID 30S TO LOW 40S SATURDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...ROBERG
AVIATION...BUTTLER
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
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 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 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 RALEIGH NC
920 PM EST SAT DEC 8 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE SOUTHEAST WILL MOVE OFFSHORE SUNDAY. A WARM
MOIST SOUTHERLY FLOW AHEAD OF AN APPROACHING COLD FRONT WILL RESULT
IN MILD TEMPERATURES THROUGH MONDAY. THE COLD FRONT WILL CROSS THE
REGION ON TUESDAY.
&&
.NEAR TERM /TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 920 PM SATURDAY...
THE MAIN UPDATES TO THE FORECAST THIS EVENING WILL BE TO ADDRESS
CLOUD COVER AND RAPIDLY FALLING TEMPS. MID CLOUDS UPSTREAM EARLIER
THIS EVENING WERE MORE ROBUST AND EVENING PRODUCING SOME VERY LIGHT
PRECIP OVER SOUTHWESTERN NC...BUT HAVE SINCE DECREASED IN COVERAGE
AS THEY DRIFT SOUTHWEST TO NORTHEAST ACROSS THE AREA. IN AREAS
WHERE SKIES HAVE BEEN MOSTLY CLEAR...PARTICULARLY OVER THE EASTERN
HALF OF THE CWA...TEMPS HAVE QUICKLY FALLEN INTO THE UPPER 40S AND
LOWER 50S. THE LATEST RAP CONTINUES TO INDICATE MOISTURE UPSTREAM
INTO THE AREA WITH A PERIOD OF ISENTROPIC LIFT SUFFICIENT FOR
SCATTERED SHOWERS...MAINLY AROUND THE WESTERN PIEDMONT. DUE TO THE
EXPECTED INCREASE IN MID LEVEL CLOUD COVER...IN THE 4000-6000 FT
RANGE BASED ON UPSTREAM OBS AND FORECAST SOUNDINGS...THERE IS STILL
SOME UNCERTAINTY REGARDING THE COVERAGE OF FOG/STRATUS. WHERE SKIES
ARE CLEAR...VISIBILITIES HAVE FALLEN INTO THE 3 TO 6 MILE RANGE IN
SOME SPOTS...BUT NO FURTHER. WILL CONTINUE TO MONITOR THESE TRENDS
TO SEE IF A DENSE FOG ADVISORY IS NEED LATER TONIGHT....BUT CURRENT
THINKING IS THAT IT MAY BE MORE LIKELY OVER EASTERN AREAS.
WITH TEMPS APPROACHING FORECAST MINS IN SOME OUTLYING AREAS...ALSO
IN RESPONSE TO THE CLEAR SKIES...WILL LOWER MIN TEMPS A COUPLE
DEGREES. HOWEVER...IF CLOUDS MOVE IN AS EXPECTED...TEMPS SHOULD
BEGIN TO LEVEL OUT AND REMAIN IN THE UPPER 40S AND LOWER 50S. -BLS
AFTER THE MORNING LOW CLOUDS/FOG LIFT AND DISPERSE AND ISOLATED
SHOWER ACTIVITY EXITS THE AREA...A MIX OF SUN AND CLOUDS WILL
SUPPORT DAYTIME HIGHS IN THE MID TO UPPER 60S NORTH TO LOWER/MID 70S
SOUTH.
THE UPSTREAM TROUGH WILL BEGIN TO DIG INTO THE SOUTHERN PLAINS
SUNDAY NIGHT WITH ATTENDANT SFC COLD FRONT ADVANCING EAST INTO THE
TN VALLEY. RISING PWATS FROM STRENGTHENING WARM MOIST AIR
ADVECTION...INCREASING RIGHT-ENTRANCE REGION DYNAMICS...THE
POTENTIAL FOR WEAK INSTABILITY ALOFT ALONG WITH THE PROSPECTS OF
SOME WEAK SHORTWAVE DISTURBANCES TO MOVE THROUGH THE AREA IN THE
SWLY FLOW ALOFT WILL SUPPORT ISOLATED SHOWERS...MAINLY IN THE WEST
LATE SUNDAY NIGHT.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SATURDAY...
A COLD FRONT WILL APPROACH AND CROSS THE REGION OVERNIGHT MONDAY
INTO TUESDAY...ALTHOUGH THERE ARE STILL SOME TIMING DIFFERENCES
AMONG THE MODELS...BUT THERE CONTINUES TO SOME TREND OF A SLOWER
PASSAGE. AHEAD OF THE FRONT...INCREASING SOUTHWESTERLY WINDS WILL
USHER IN MOISTURE AND EVEN MORE WARMTH DURING THE DAY ON MONDAY.
TEMPS ARE EXPECTED TO RANGE FROM THE LOW 70S ACROSS THE NORTHWEST TO
THE MID 70S FURTHER SOUTH AND EAST. THERE COULD EVEN BE SOME UPPER
70S ACROSS THE SOUTHEAST...ALTHOUGH THE AMOUNT OF CLOUD COVER WILL
BE THE DETERMINING FACTOR AND AT THIS TIME...IT LOOKS LIKE THERE
WILL BE SUFFICIENT CLOUD COVER TO HOLD TEMPS DOWN SOME. HEATING MAY
ALSO BE TEMPERED SOME IN THIS REGION AS DEWPOINTS RISE INTO THE
LOWER 60S.
PRECIP CHANCES WILL INCREASE DURING THE DAY ON MONDAY AS WARM AIR
ADVECTION INCREASES ACROSS THE REGION...WITH SOME SPOTTY SHOWERS
POSSIBLE DURING THE DAY. THE BEST CHANCE OF PRECIP WILL COME
OVERNIGHT ON MONDAY AND INTO EARLY TUESDAY AS THE FRONT CROSSES THE
AREA. AS STATED ABOVE...THERE ARE SOME TIMING DIFFERENCES WITH
RESPECT TO THE SPEED OF THE FRONT...BUT WILL CONTINUE TO SHOW PRECIP
CHANCES TRENDING DOWNWARD LATE TUESDAY AFTERNOON/EVENING.
INSTABILITY APPEARS TO BE MARGINAL (AT BEST) AS THE FRONT CROSSES
THE AREA MONDAY NIGHT...BUT CANNOT COMPLETELY RULE OUT AN ISOLATED
THUNDERSTORM OR TWO.
TEMPS MONDAY NIGHT AND TUESDAY WILL ULTIMATELY BE DETERMINED BY THE
TIMING OF THE FRONT AND ASSOCIATED PRECIP AND EVENTUAL CAA. WITH THE
SLIGHTLY SLOWER FRONTAL TIMING...WILL SHOW MILD TEMPS MONDAY
NIGHT...GENERALLY IN THE 50S. HIGHS ON TUESDAY ARE EXPECTED TO BE IN
THE MID/UPPER 50S TO LOW/MID 60S AND MAY VERY WELL OCCUR IN THE
MORNING AND THEN FALL THROUGHOUT THE DAY. OVERNIGHT LOWS TUESDAY
NIGHT WILL LIKELY BE IN THE MID/UPPER 30S TO NEAR 40 DEGREES.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...
WEDNESDAY THROUGH THURSDAY...THEN THERE IS QUITE A BIT OF
UNCERTAINTY WITH RESPECT TO THE WEATHER FOR THIS TIME FRAME. BOTH
THE GFS AND ECMWF SHOW THE FRONT HANGING NEAR THE COAST WITH
MULTIPLE LOW PRESSURE WAVES TRACKING ALONG IT AND SPREADING PRECIP
INTO EASTERN NC...ALTHOUGH HOW FAR EAST IS IN QUESTION. THE GFS THEN
SHOWS A MID LEVEL KICKER WAVE MOVING INTO THE AREA WEDNESDAY WHICH
WOULD PUSH THE FRONT AND ASSOCIATED PRECIP OUT TO SEA. THE ECMWF IS
ALMOST 12-18 HOURS SLOWER WITH THIS MID LEVEL WAVE...HOWEVER THIS IS
SLIGHTLY FASTER THAN PREVIOUS RUNS OF THE ECMWF...SO THIS WILL HAVE
TO BE MONITORED. FOR NOW...WILL GO NO MORE THAN SLIGHT CHANCE POPS
FOR THIS TIME FRAME UNTIL MODELS COME INTO BETTER AGREEMENT AND WILL
JUST KEEP POPS CONFINED TO THE EASTERN PORTIONS OF THE FORECAST
AREA. TEMPS WILL LIKELY BE NEAR TO SLIGHTLY ABOVE NORMAL DURING THIS
TIME FRAME.
FRIDAY THOUGH SATURDAY...CONDITIONS THEN LOOK TO IMPROVE FOR THE END
OF THE WORK WEEK AS SURFACE HIGH PRESSURE AND MID LEVEL RIDGING
BUILD INTO THE AREA. MODELS THEN SHOW THE NEXT SYSTEM APPROACHING
THE REGION OVER THE WEEKEND...WITH CLOUDS AND PRECIP CHANCES
POSSIBLY BEGINNING TO INCREASE LATE SATURDAY (ALTHOUGH TIMING THIS
FAR OUT IS ALWAYS IN QUESTION). TEMPS WILL SLOWLY MODERATE AT THE
END OF THE WEEK AND ESPECIALLY INTO SATURDAY AS THE SURFACE HIGH
MOVES OFFSHORE AND SOUTHERLY FLOW RETURNS TO THE AREA.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 655 PM SATURDAY...
LOWER-THAN-USUAL CONFIDENCE IN THE AVIATION FORECAST DUE TO
CONFLICTING MODEL GUIDANCE. VFR CONDITIONS CURRENTLY IN PLACE OVER
ALL CENTRAL NC FORECAST LOCATIONS IS LIKELY TO DROP TO SUB-VFR
MAINLY AFTER MIDNIGHT. HOWEVER... JUST HOW LOW CIGS/VSBYS WILL GET
WILL DEPEND ON THE EXTENT OF MID AND HIGH CLOUDS NOW MOVING INTO THE
AREA FROM THE SW... WHICH WOULD FAVOR LESS RADIATIONAL COOLING AND
WOULD FAVOR CIGS/VSBYS FALLING TO MVFR OR IFR RATHER THAN LIFR
TONIGHT. FORECAST SOUNDINGS SUGGEST LIFR CONDITIONS... WHEREAS THE
SREF PROBABILITIES AND STATISTICAL GUIDANCE FAVOR MVFR OR IFR. TAFS
REFLECT A LEAN TOWARD THE LATTER SOLUTION WITH CIGS FALLING AFTER
04-06Z TO 1-2SM IN FOG/MIST WHILE CIGS DROP TO MVFR THEN IFR...
AROUND 8 HUNDRED FT AGL. A FEW SHOWERS ARE POSSIBLE NEAR INT/GSO/RDU
BETWEEN 07Z AND 14Z. AS SW SURFACE WINDS INCREASE TO 5-10 KTS AFTER
14Z... VSBYS WILL IMPROVE TO VFR WHILE CIGS RISE TO MVFR SLOWLY
BEFORE RISING ABOVE 3 THOUSAND FT AGL AFTER 17Z... LASTING THROUGH
THE AFTERNOON/EARLY EVENING.
LOOKING BEYOND 00Z MONDAY... PERIODS OF ADVERSE AVIATION CONDITIONS
ARE APT TO PERSIST THROUGH MID WEEK. A BREEZE FROM THE SW WILL HOLD
SUNDAY EVENING AND NIGHT WITH A HIGH CHANCE OF IFR/LIFR CONDITIONS
RETURNING AFTER 05Z. CIGS WILL SLOWLY RISE TO VFR BY 18Z MONDAY...
THEN DROP BACK TO IFR/LIFR MONDAY EVENING AHEAD OF THE INCOMING COLD
FRONT. CIGS WILL SLOWLY RISE TO MVFR THEN VFR ON TUESDAY WITH
FRONTAL PASSAGE AND JUST BEHIND THE FRONT. MVFR CONDITIONS MAY
RETURN TUESDAY NIGHT INTO WEDNESDAY MORNING. THEN... VFR CONDITIONS
WITH HIGH PRESSURE IS LIKELY LATE WEDNESDAY THROUGH THURSDAY. -GIH
&&
.CLIMATE...
DAILY RECORD HIGHS FOR MONDAY (DECEMBER 10):
RDU: 81 (2007)
GSO: 78 (2007)
FAY 79 (2007)
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL/SEC
NEAR TERM...CBL/BLS
SHORT TERM...KRR
LONG TERM....KRR
AVIATION...HARTFIELD
CLIMATE...RAH
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 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...UPDATED
NWS GRAND FORKS ND
919 PM CST SAT DEC 8 2012
.DISCUSSION...CONFIENCE IS NOW VERY HIGH WITH THE TRACK OF THIS
SYSTEM GIVEN CURRENT OBSERVATIONS AND INCOMING 00Z MODEL RUNS. SFC
LOW ACROSS SOUTHCENTRAL SOUTH DAKOTA WILL PROPAGATE EAST INTO
SOUTHERN MINNESOTA ON SUNDAY. THIS PLACES THE STRONGEST FORCING
(DEFORMATION) SOUTH OF THE FA WITH THE EXTREME SOUTHERN FA ON THE
NORTHERN EDGE OF THE SIGNIFICANT SNOWFALL. AREAS ACROSS THE
SOUTHERN PORTION OF THE WINTER STORM WARNING SHOULD GET 5-8 INCHES
OF SNOW...WHILE AREAS ACROSS THE NORTHERN PORTION OF THE WARNING
GET 2-5 INCHES. STRONG 850MB FRONTOGENESIS TO THE NORTH WILL
SLOWLY SINK SOUTH INTO SUNDAY MORNING. ALTHOUGH SYNOPTIC FORCING
IS WEAK WITHIN THIS FORCING...HIGHER SNOW RATIOS (15:1-20:1) WILL
LIKELY LEAD TO 2-4 INCHES OF NEW SNOW FOR AREAS NORTH OF THE
WARNING. THESE SNOWFALL TOTALS ARE CLOSE TO THE PREVIOUS FORECAST
AND ONLY MINOR ADJUSTMENTS WERE PERFORMED. WINDS WILL NOT BE QUITE
AS STRONG ACROSS THE FAR NORTHERN FA WITH THE EXPECTED TRACK OF
THE SFC LOW FURTHER SOUTH...AND WILL REPLACE THE WINTER WEATHER
ADVISORY WITH A WIND CHILL ADVISORY ACROSS THIS AREA (WIND CHILL
VALUES -25F TO -35F) THROUGH 18Z.
THIS LEADS TO THE MAIN QUESTION...ARE THE EXPECTED WINDS ENOUGH
FOR A BLIZZARD WARNING ACROSS SOUTHEAST NORTH DAKOTA AND THE
SOUTHERN RED RIVER VALLEY (SOUTH OF FARGO). CANADIAN BLOWING SNOW
MODEL SUGGESTS WIND SPEEDS AROUND 32 KNOTS WILL BE NEEDED FOR A
WIDESPREAD BLIZZARD. SUSTAINED WINDS LIKELY WILL BE AROUND 26
KNOTS...WITH GUSTS TO AROUND 40 KNOTS. SO...WILL THE GUSTS BE
FREQUENT ENOUGH TO CREATE BLIZZARD CONDITIONS. STRONGEST SFC
PRESSURE RISE MAXIMUM AND 925MB COLD AIR ADVECTION LOOK TO PASS
JUST SOUTH OF THE FA...WHICH WOULD LIMIT MIXING POTENTIAL ACROSS
OUR SOUTHERN FA. THIS ALL SUGGESTS THAT A WARNING IS STILL THE
BEST OPTION. WILL NEED TO MONITOR THE SITUATION CLOSELY...AND NEAR
BLIZZARD CONDITIONS ARE LIKELY NEAR THE SOUTH DAKOTA BORDER...BUT
A WINTER STORM WARNING TAKES CARE OF THE SITUATION BEST AT THIS
POINT. DID REMOVE THE BLOWING SNOW MENTION ACROSS PORTIONS OF THE
NORTHERN FA WITH WIND SPEEDS SLIGHTLY LESS HERE.
&&
.AVIATION...MVFR/IFR CONDITIONS ACROSS ALL TAF SITES ALONG WITH
LIGHT SNOW WILL CONTINUE THROUGH MUCH OF THE NIGHT INTO SUNDAY
MORNING. CLEARING SKIES WILL MOVE IN FROM THE NORTH...LATE TONIGHT
INTO SUNDAY. WINDS WILL INCREASE FROM THE NORTH ALONG THE
VALLEY...WITH BLOWING SNOW LIKELY FOR KGFK AND KFAR.
&&
.PREV DISCUSSION... /ISSUED 309 PM CST SAT DEC 8 2012/
SHORT TERM...
QUITE CHALLENGING TODAY. MODELS KEEP TRACKING LOW A BIT FARTHER
SOUTH EACH RUN AND 12Z GFS AND LATEST RAP MODEL GO ALONG WITH 00Z
AND 12Z EURO IN HAVING LOW JUST NORTH OR NORTHEAST OF SIOUX FALLS
AT 12Z SUN. TRACK OF MID LEVEL LOW WOULD BRING HEAVIEST SNOW INTO
MOSTLY NORTHERN INTO NORTHEAST AND EAST CENTRAL SOUTH DAKOTA
TOWARD PERHAPS ST CLOUD AND THE NRN TWIN CITIES METRO AREA
OVERNIGHT INTO SUNDAY. THUS HEAVIEST SNOW NOW JUST CLIPS THE FAR
SOUTH FCST AREA IN WARNING AREA. FARTHER SOUTH TRACK GIVES A BIT
MORE CONFIDENCE NOW TO LEAVING STRETCH FROM VALLEY CITY TO FARGO
TO PARK RAPIDS IN ADVISORY FOR UP TO 4 INCHES WITH LESS FARTHER
NORTH.
NOW WILL ADD A FEW COUNTIES IN THE FAR NORTH ALONG ND/MB
BORDER TO WINTER WX ADVISORY TONIGHT AS AREA THERE RECEIVED 4
INCHES OF FLUFF ACCORDING TO SPOTTERS AND WILL EASILY BLOW AROUND
TONIGHT AS WINDS UP THERE INCREASE TO AROUND 20 MPH. PLUS WIND
CHILLS WILL DROP TO BELOW -25F LATER TONIGHT.
925 MB WINDS FARTHER SOUTH WILL INCREASE GREATLY 06Z TO 09Z FROM
NEAR GRAND FORKS SOUTH INTO ERN SD WITH 40-45 KTS THERE AND DUE TO
PRESSURE GRADIENT AND COLD ADVECTION SHOULD SEE GUSTS OVER 30 KTS
ESP IN SE ND IN THAT 09Z TO 18Z PERIOD. WINDS WILL HIT AFTER THE
MAIN SNOW AND WITH MAIN SNOW BEING LESS IN ALL BUT FAR SOUTH THAN
EARLIER THINKING STILL THINK ADV OK RIGHT NOW. COULD SEE BLIZZARD
CONDITIONS DEVELOP HOWEVER BUT QUITE IFFY ON THIS...MORE OF AN
OPEN COUNTRY THING VS IN TOWN AS MAIN SNOWFALL ITSELF IS JUST A
BIT SOUTH. EVE SHIFT CAN MONITOR.
SYSTEM WILL MOVE EAST SUNDAY AND SNOW AND WIND WILL
DIMINISH...SNOW FIRST THEN WIND. VERY COLD WITH 12Z-18Z WIND
CHILLS TO -30 IN THE FAR NORTHWEST FCST AREA. WILL LET MID SHIFT
ISSUE ANY WC HEADLINES. DIDNT WANT TO EXTEND WINTER WX HEADLINES
PAST 12Z SUN UP IN THE FAR NORTHWEST AS WINDS WILL DIMINISH THERE
FIRST.
HIGH PRESSURE WILL MOVE IN SUN NIGHT AND SOME SPOTS WILL GET INTO
THE NEGATIVE TEENS. CLOUDS WILL MOVE IN LATE SUN NIGHT INTO MONDAY
AND TUESDAY AS SEVERAL SHORT WAVES MOVE THROUGH BUT DOES LOOK
MAINLY DRY. COULD BE A FEW SPITS OF -SN BUT DID NOT MENTION YET.
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
12 UTC GFS/ECMWF IN REASONABLE AGREEMENT NEXT WEEK...BOTH SHOWING
NORTHWEST FLOW ALOFT SHIFTING TO THE WEST/SOUTHWEST THROUGH THE
PERIOD. BEST CHANCE FOR SNOW WILL BE ALONG AND NORTH OF THE HIGHWAY
2 CORRIDOR ON WEDNESDAY AS A WEAK SHORT-WAVE MOVES ACROSS SOUTHERN
CANADA. THURSDAY INTO EARLY NEXT WEEKEND LOOK MAINLY DRY AS MAJORITY
OF ENERGY ALOFT GETS SHUNTED TO THE SOUTH WITH FOUR CORNERS TROUGH.
THIS FEATURE EJECTS NORTHEASTWARD AND INTO SOUTHEAST MN/WEST CENTRAL
WI BY SATURDAY...SO WILL NEED TO WATCH FOR ANY NORTHWARD OR WESTWARD
SHIFTS...REQUIRING AN INCREASE IN THE CURRENT ALL BLEND 20 POPS.
TEMPERATURES WILL BE SEASONABLE ON WEDNESDAY WITH HIGHS IN THE 20S
BEFORE A COOL-DOWN FOR THE LATTER HALF OF THE WEEK AFTER A COLD
FRONT MOVES THROUGH WEDNESDAY NIGHT. HIGHS THURSDAY/FRIDAY WILL
RANGE FROM THE SINGLE DIGITS ABOVE ZERO TO THE UPPER TEENS TO NEAR
20 DEGREES.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 6 PM CST SUNDAY FOR NDZ024-026>030-
038-039.
WINTER STORM WARNING UNTIL 6 PM CST SUNDAY FOR NDZ049-052-053.
WIND CHILL ADVISORY UNTIL NOON CST SUNDAY FOR NDZ006>008-014>016-
054.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST SUNDAY FOR MNZ001>003-
013>017-022>024-027-028.
WINTER STORM WARNING UNTIL 6 PM CST SUNDAY FOR MNZ029>032-040.
WIND CHILL ADVISORY UNTIL NOON CST SUNDAY FOR MNZ004-007.
&&
$$
TG
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1011 PM EST SAT DEC 8 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE GREAT LAKES IN THE WAKE OF A
DEPARTING COLD FRONT TONIGHT. THIS WILL GIVE A BRIEF RESPITE TO
THE RAINFALL UNTIL A WARM FRONT DEVELOPS OVER KENTUCKY EARLY
SUNDAY AND THEN LIFTS NORTHWARD. LOW PRESSURE WILL THEN TRACK
NORTHEAST THROUGH THE OHIO VALLEY AND ANOTHER COLD FRONT OVER THE
AREA WILL BE THE FOCUS FOR MORE RAINFALL SUNDAY NIGHT AND MONDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
SHOWERS AND A FEW THUNDERSTORMS HAVE BEEN DEVELOPING ACROSS
KENTUCKY OVER THE PAST FEW HOURS WITH A WARM FRONT OVER THE AREA.
EXPECT THE SHOWERS TO REMAIN MAINLY ALONG AND SOUTH OF THE OHIO
RIVER INTO THE EARLY MORNING HOURS PER THE LATEST HRRR AND RAP13
RUNS...BUT THE RAIN WILL LIKELY BEGIN TO SPREAD FURTHER NORTH
TOWARDS DAYBREAK. BUMPED UP POPS A BIT TO ACCOUNT FOR THIS. REST
OF FORECAST LARGELY REMAINS ON TRACK WITH ONLY A FEW MINOR TWEAKS.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
WARM FRONT OVER KENTUCKY LIFTS NORTH THROUGH OHIO DURING THE DAY
SUNDAY AND A SURFACE LOW TRACKS EAST ALONG IT AS IT DOES. THE
COMBINATION OF THE TWO WILL MEAN ANOTHER MILD DAY WITH AN EVER-
INCREASING CHANCE FOR SHOWERS.
ONCE THE LOW REACHES LAKE ERIE SUNDAY NIGHT...A COLD FRONT
ORIENTED ALONG THE I-71 CORRIDOR WILL BE A FOCUS FOR SHOWERS AND
EVEN SOME THUNDERSTORMS. RAIN AT TIMES COULD BE MODERATE IN
INTENSITY AND RIVERS AND STREAMS THAT MAY BE RUNNING HIGH WILL
NEED TO BE MONITORED A LITTLE CLOSER AS THE NEXT ROUND OF RAIN
COMES IN. THE MODERATE RAINFALL WILL PROBABLY OCCUR IN THE LATER
EVENING AS THE FLOW AT THE SURFACE AND ALOFT IS NEAR PARALLEL
SOUTHWEST TO NORTHEAST. THIS WILL TAP THE AVAILABLE GULF MOISTURE
WITH A STRONG TRANSPORT WIND OVER THE REGION UNTIL THE SURFACE
GRADUALLY SHOWS AND EASTWARD PROGRESSION ON MONDAY IN RESPONSE TO
THE COLDER AIR BEING USHERED IN ON NORTHWEST WINDS.
A LARGE PORTION OF THE ATMOSPHERE WILL SEE QUITE A BIT OF
SLANTWISE CONVECTION AND THE THREAT FOR THUNDER IN THESE SHOWERS
IS HIGHER THAN AVERAGE...THOUGH THE SEVERE THREAT INHERENT WITH
THUNDERSTORMS WILL BE QUITE MINIMAL IF IT DOES EXIST AT ALL. I
TOOK NAM CAPE VALUES OVER 30 TO INDICATE THE THREAT FOR THUNDER.
WITH REGARDS TO THE HEAVIER RAIN...THIS STARTED SUNDAY EVENING AND
RAN THROUGH MONDAY EVENING WHERE POPS LIKELY OR HIGHER WERE BEING
FORECAST. THE RAIN WILL TURN OFF NORTHWEST TO SOUTHEAST ON MONDAY
WITH VERY LITTLE ACTIVITY SLATED TO REMAIN MONDAY NIGHT. THE
DEEPER COLD AIR IS WELL BEHIND THE RAINFALL SO I HAVE REMOVED
MENTION OF ANY SNOW.
TEMPERATURES WERE ONLY MINORLY ADJUSTED AND ARE SHOWING A PRETTY
GOOD CONSISTENCY BETWEEN GUIDANCE VALUES AND THE PREVIOUS
FORECAST.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS THE PERIOD BEGINS...THE MODELS ARE SHOWING SFC HIGH PRESSURE
BEGINNING TO PUSH INTO THE REGION. THE HIGH STRENGTHENS IT GRIP OVER
THE REGION DURING THE DAY TUESDAY. THE CENTER OF THE HIGH WILL
STRETCH OVER THE UPPER OHIO VALLEY BY DAYBREAK ON WEDNESDAY AND HIGH
PRESSURE WILL CONTROL THE REGIONS WEATHER INTO FRIDAY.
RIGHT NOW MODELS ARE IN GOOD AGREEMENT IN FORMING A SFC LOW IN THE
PLAINS ON FRIDAY AND EJECTING IT OUT INTO THE WESTERN LAKES BY
SATURDAY. FA WILL ONCE AGAIN BE ON THE WARM SIDE OF THE SYSTEM...SO
IT LOOKS LIKE A ANOTHER SHOT OF RAIN FOR NEXT SATURDAY.
TUESDAY SHOULD BE THE COLDEST DAY OF THE WEEK WITH CAA BEHIND THE
DEPARTING SYSTEM. HIGH WILL ONLY BE IN THE MID 30S TO AROUND 40.
MOSTLY CLEAR SKIES TUESDAY WITH THE BUILDING HIGH SHOULD ALLOW
TEMPERATURES TO FALL BACK INTO THE LOWER TO MID 20S. A GRADUAL WARM
UP THEN BEGINS ON WEDNESDAY AS HIGH ARE EXPECTED TO PUSH INTO THE
LOWER TO MID 40S. HIGHS WILL PUSH INTO THE UPPER 40S TO LOWER 50S BY
THE END OF THE WEEK.
ANOTHER COOL NIGHT IS EXPECTED WEDNESDAY NIGHT WITH TEMPERATURES
FALLING BACK INTO THE 20S BEFORE THE WARMER AIR BEGINS TO WORK IN
AHEAD OF THE DEVELOPING SYSTEM BY THE END OF THE PERIOD.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
MVFR CEILINGS SHOULD PERSIST THROUGH THE EARLY PART OF THE TAF
PERIOD. LATER IN THE EXPECT CEILINGS AND VISIBILITIES TO LOWER AS
A WARM FRONT STRENGTHENS TO THE SOUTH OF THE REGION. SOME SHOWERS
WILL LIFT NORTH AHEAD OF THE WARM FRONT. BUT MAIN CONCERN WILL BE
IFR CEILINGS WHICH FOR THE MOST PART WILL NOT BE ABLE TO LIFT TO
OR ABOVE 1000 FT UNTIL AFTER THE WARM FRONT PASSES. AND THAT IS
NOT FORECAST UNTIL 15Z OR LATER. ADDITIONAL SHOWERS WILL DEVELOP
LATE IN THE TAF PERIOD AS AN AREA OF LOW PRESSURE APPROACHES FROM
THE WEST. SOME INSTABILITY IS EXPECTED TO DEVELOP AHEAD OF THIS
LOW WHICH COULD LEAD TO A FEW THUNDERSTORMS. AT THIS POINT THE
GREATEST PROBABILITY IS IN THE CINCINNATI AREA BUT A STORM CANNOT
BE RULED OUT AT ANY OF THE TERMINALS.
OUTLOOK...IFR CEILINGS AND MVFR VISIBILITIES LIKELY SUNDAY NIGHT
WITH IMPROVEMENT TO MVFR CEILINGS ON MONDAY. MVFR CEILINGS MAY
LINGER INTO MONDAY NIGHT AND TUESDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...KURZ
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...
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 GREENVILLE-SPARTANBURG SC
726 PM EST SAT DEC 8 2012
.SYNOPSIS...
WARMING SOUTHWEST FLOW WILL PERSIST OVER THE REGION THIS WEEKEND.
SHOWER CHANCES ARE EXPECTED TO INCREASE BY MONDAY OUT AHEAD OF AN
APPROACHING COLD FRONT. COOLER HIGH PRESSURE WILL MOVE BACK INTO
THE CAROLIANS FOR MID WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
645 PM UPDATE...THE SHOWER ACTIVITY HAS DECREASED OVER THE AREA THIS
EVENING AND THUS POPS HAVE BEEN LOWERED ACCORDINGLY. STILL EXPECT
MOSTLY CLOUDY SKIES WITH AREAS OF FOG DEVELOPING ACROSS MUCH OF OUR
CWA THROUGH THE OVERNIGHT. THE FOG COULD BECOME DENSE BY LATE
TONIGHT MAINLY OVER LAKE REGIONS AND NC MOUNTAIN VALLEYS AND
NORTHERN NC PIEDMONT.
500 PM UPDATE...A BAND OF LIGHT PRECIP HAS MOVED INTO THE UPSTATE SC
AND NE GEORGIA THIS AFTERNOON AND IT WILL CONTINUE TO PROGRESS EAST
ACROSS SC PEDIMENT THROUGH TONIGHT. PRECIP AMOUNTS SHOULD BE LIGHT
AND SOME LOCAL PATCHES OF FOG COULD ACCOMPANY THE BAND OF PRECIP.
THE LATEST RUC INDICATES THAT THE SHOWER ACTIVITY WILL DECREASE BY
LATE TONIGHT. ANOTHER AREAS OF FOG WILL DEVELOP ACROSS MUCH OF OUR
CWA TONIGHT INTO TOMORROW MORNING.
AS OF 200 PM...A PLUME OF GULF MOISTURE CAN BE SEEN ON VISIBLE
SATELLITE IMAGERY STREAMING WITHIN LLVL SWLY RETURN FLOW...WITH
LEADING EDGE OF STRATUS AND LGT SHWRS ENTERING THE WRN PORTIONS OF
THE CWFA. BOTH THE NAM AND GFS KEEP MOST OF THE ASSOCIATED ISENT
LIFT AND RH CONFINED TO THE SW NC MTNS AND UPR SAVANNAH VLY INTO
THIS EVENING...AS FLOW HAS ANTICYCLONIC CURVATURE AND HAS DOWNSLOPE
COMPONENT TO THE EAST. WITH THAT SAID...OVERALL INCREASING CLOUD
COVER AND POP IS EXPECTED ACRS THE ENTIRE AREA TNGT...AS A BRIEF
PERIOD OF ISENT LIFT AND RH TRANSLATES WEST TO EAST ACRS THE AREA.
TEMPS WILL BE 10-15 DEG ABOVE NORMAL OVERNIGHT...DROPPING ONLY INTO
THE MID 40S TO LWR 50S.
SUNDAY...GUIDANCE SHOWS THE CWFA COMPLETELY WITHIN THE WARM SECTOR
OF A DEVELOPING LOW PRES SYS OVR THE MID MS VLY. ISENT LIFT WEAKENS
AND DEEPER RH SHIFTS EAST. FCST SNDGS DO SHOW SOME SBCAPE...ESP ACRS
THE PIEDMONT...AS CLOUDS BREAK OUT AND TEMPS WARM INTO THE UPR 60S
TO NEAR 70. HOWEVER...A MID LVL INVERSION IS LIKELY TO CAP ANY
DEEPER CONVECTION. BESIDES LIMITED INSTBY...NO SIGNIFICANT MID OR
UPR LVL FORCING....AND LLVL LIFT WILL BE CONFINED TO SWLY UPSLOPE
FLOW IN THE SW NC MTNS. SO I HAVE POPS TAPERING OFF FROM CHC MTNS
AND SLGT CHC PIEDMONT IN THE MORNING TO ONLY A SLGT CHC IN THE NC
FOOTHILLS/NW PIEDMONT BY EARLY EVENING.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 300 PM SATURDAY...THE MAIN FEATURE FOR THE SHORT RANGE
CONTINUES TO BE THE COLD FRONTAL PASSAGE LATE MONDAY OR MONDAY NITE.
THE GUIDANCE IN GENERAL SEEMS TO HAVE SLOWED SLIGHTLY WITH FROPA.
THAT SAID...THERE IS STILL SOME SPREAD IN THE TIMING OF THE FRONT.
THERE IS ALSO DISAGREEMENT ON THE DEVELOPMENT OF A SFC WAVE AND
WHETHER OR NOT IT MOVES ACROSS THE CWFA. THE GUIDANCE DOES AGREE
THAT ANY LINGERING LIGHT PRECIP SUNDAY EVENING WILL END BEFORE
MIDNIGHT AS LIFT DIMINISHES AND LOW LEVEL MOISTURE BECOMES SHALLOW.
HOWEVER...DEEPER MOISTURE AND FORCING ASSOCIATED WITH THE
APPROACHING FRONT WILL MOVE INTO THE MTNS AFTER MIDNIGHT SO PRECIP
CHC RETURNS BY DAYBREAK. WITH THE CONTINUED CLOUDS...SLY FLOW AND
HIGH THICKNESS VALUES...LOWS WILL BE 10 TO 20 DEGREES ABOVE NORMAL.
WITH THE FROPA TENDING TO SLOW...THIS ALSO SLOWS THE INCREASE IN
MOISTURE AND FORCING OUTSIDE OF THE MTNS. THEREFORE...DO NOT BRING
ANY CHC POP TO THE NC PIEDMONT AND ERN UPSTATE UNTIL LATE AFTERNOON
WITH CHC ACROSS THE FOOTHILLS AND WRN UPSTATE BY EARLY AFTERNOON.
THERE IS AGREEMENT THAT THE MTNS WILL SEE PRECIP ON MONDAY...BUT IT
IS SLOWED AS WELL...SO SHOW A SLOW INCREASE THRU LIKELY TO CAT POP
BY LATE IN THE DAY. THERE IS STILL LITTLE IN THE WAY OF SFC
INSTABILITY...BUT THERE LOOKS TO BE SOME WEAK ELEVATED INSTABILITY
AS LAPSE RATES INCREASE THRU THE DAY. THUNDER COULD DEVELOP JUST
ABOUT ANYWHERE EXCEPT THE NRN FOOTHILLS AND ALL BUT THE FAR SWRN NC
MTNS. THE FRONT LOOKS TO MOVE ACROSS THE CWFA MON NITE. SHEAR STILL
EXPECTED TO BE VERY STRONG WITH SOME HELICITY DEVELOPING. WITH THE
WEAK ELEVATED INSTABILITY...SVR QLCS STORMS COULD DEVELOP. IF THE
SFC LOW FORMS ALONG THE FRONT AND MOVES ACROSS THE I-85 OR SOUTH
CORRIDOR...THEN SVR CHC WOULD INCREASE AS LOW LEVEL FORCING AND
HELICITY COULD BE HIGHER. THIS COULD ALSO SLOW THE MOVEMENT OF THE
FRONT KEEPING SVR CHC INTO THE EVENING OR EVEN LATER. HAVE LIMITED
CAT POP TO THE MTNS FOR THE EVENING AND LIKELY ALL OTHER AREAS GIVEN
THE EXPECT TIMING UNCERTAINTY. THE GUIDANCE AGREES THAT LOWS MON
NITE AND PARTIAL THICKNESSES WILL BE HIGHER THAN PREV FCST. IN
ADDITION...GUIDANCE IS TRENDING AWAY FROM ANY TRADITIONAL NW FLOW
TYPE PRECIP. THEREFORE... HAVE REMOVED ANY SNOW MENTION LATE MON
NITE.
PRECIP SHUD DIMINISH TUE MORNING WITH ONLY SOME LINGERING ISOLATED
SHRA TUE AFTERNOON SOUTH OF I-85. HIGHS SHUD BE WARMER THAN EARLIER
EXPECTED AS WELL...NEAR NORMAL MTNS AND 5 TO 10 DEGREES ABOVE NORMAL
ELSEWHERE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AT 240 PM EST SATURDAY...THE AFOREMENTIONED FRONTAL BOUNDARY SHOULD
GRADUALLY GET A PUSH EAST TUESDAY NIGHT...AS A SECONDARY UPSTREAM
TROF INFLUENCES SENSIBLE WEATHER. THIS SHOULD CONCLUDE PRECIPITATION
CHANCES ACROSS OUR FORECAST AREA (FA). ALTHOUGH PRECIPITATION WILL
EITHER END OR EXIT...SOUNDING DATA SUGGESTS CLOUDS WILL LINGER MUCH
OF TUESDAY NIGHT...AND PLAN TO HOLD THAT LINE.
A LARGE AREA OF SURFACE HIGH PRESSURE WILL THEN SETTLE ACROSS OUR
FORECAST AREA (FA) WEDNESDAY AND THURSDAY...WHILE A FLAT 500 MB
RIDGE PREVAILS. THIS SHOULD SPELL QUIET WEATHER CONDITIONS DURING
MID WEEK.
AS WE REACH TOWARD THE START OF NEXT WEEKEND...THE H5 RIDGE WILL
HAVE SHIFTED OFF INTO THE ATLANTIC...AS WELL AS THE SURFACE HIGH.
SOUTHWESTERLY FLOW AT THE SURFACE AND ALOFT WILL BEGIN TO DRIVE
DEEPER MOISTURE INTO OUR REGION FRIDAY NIGHT...AND WILL PROBABLY
LAST THROUGH MUCH OF THE WEEKEND.
WARM AIR ADVECTION PRECIPITATION MAY BREAK OUT OVER THE NC MOUNTAINS
IN THE WEE HOURS SATURDAY MORNING. INCOMING CLOUDS SHOULD CAP
TEMPERATURES ABOVE FREEZING...SO AT THIS POINT WE ARE PAINTING
LIQUID AS THE PRECIPITATION TYPE. THE WARM AIR ADVECTION PATTERN
WILL THEN GRADUALLY ENCOMPASS MUCH OF OUR FA SATURDAY AND SATURDAY
NIGHT WITH A CHANCE OF SHOWERS. WILL HOLD POPS IN THE CHANCE FIELD
THIS FAR OUT...BUT WOULD NOT BE SURPRISED FOR A MORE ROBUST EPISODE.
A COLD FRONT WILL THEN BE APPROACHING / OR CROSSING / OUR REGION
LATE SATURDAY NIGHT OR BEYOND.
THE GFS IS VERY ROBUST WITH ITS PRECIPITATION FIELDS WHILE THE NEW
EUROPEAN MODEL...ALTHOUGH NOT AS BULLISH...HAS BROUGHT MORE QPF INTO
OUR FA AT THE START OF NEXT WEEKEND...COMPARED TO ITS 00Z RUN.
THERE SEEMS TO BE VERY LITTLE TO QUIBBLE WITH AS FAR AS TEMPERATURES
ARE CONCERNING...WITH SOME MINOR ADJUSTMENTS DURING THOSE PERIODS
WHEN CLOUDS ARE EXITING OR ENTERING THE FA.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
AT KCLT...VFR CONDITIONS WILL CONTINUE OVERNIGHT AND INTO SUN
MORNING. THE LATEST GUIDANCE INDICATES THAT LIGHT SW WINDS WILL
CONTINUE THROUGH THE OVERNIGHT HOURS WHICH SHOULD LEAD TO PREVAILING
VFR CEILINGS AND VIS. SOME PATCHY FOG MAY DEVELOP TOWARD DAYBREAK
BUT NOT EXPECTING ANY VSBY RESTRICTIONS AT THIS TIME. INCREASING
SOUTHERLY ISENTROPIC LIFT WILL RESULT IN CLOUD CEILINGS LOWERING TO
2K FT IN MVFR CONDITION BY 18Z.
ELSEWHERE...LIGHT SCATTERED SHOWERS HAVE DIMINISHED ACROSS SC
PIEDMONT THIS EVENING. HOWEVER ANOTHER ROUND OF SHOWER ACTIVITY MAY
RETURN TO NE GA AND WESTERN NC MTNS BY LATE TONIGHT. GUIDANCE
INDICATES THAT AREAS OF DENSE FOG WILL DEVELOP ACROSS NC MOUNTAIN
VALLEYS AND NORTHERN NC PIEDMONT TOWARD DAYBREAK WHICH SHOULD LEAD
TO VSBY RESTRICTIONS OVER KAVL AND KHKY TERMINALS. ELSEWHERE WILL
SEE PREVAILING VFR CONDITIONS OVERNIGHT THOUGH PATCHY FOG IN BRIEF
MVFR CONDITIONS MAY DEVELOP TOWARD DAYBREAK. ANY FOG SHOULD BURN OFF
SHORTLY AFTER SUNRISE. INCREASING SOUTHERLY ISENTROPIC LIFT AND LLVL
MOISTURE ADVECTION WILL SUPPORT MVFR CEILINGS BY LATE SUN
MORNING..IF NOT BY EARLY AFTERNOON. LIGHT SW WINDS WILL CONTINUE
OVERNIGHT ACROSS THE PIEDMONT WITH CALM CONDITIONS OVER NC VALLEYS.
WINDS WILL INCREASE ACROSS ALL TERMINALS BY EARLY SUN AFTERNOON.
OUTLOOK...CONDITIONS ARE EXPECTED TO IMPROVE TO VFR ON SUNDAY. THEN
PATCHY FOG AND STRATUS WILL BE POSSIBLE AGAIN MONDAY MORNING. A
STRONG COLD FRONT WILL ENTER THE REGION ON MONDAY AND PUSH THRU
OVERNIGHT MONDAY NIGHT...ACCOMPANIED BY SHOWERS AND THUNDERSTORMS
ALONG WITH GUSTY WINDS.
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...ARK/JOH
SHORT TERM...RWH
LONG TERM...TS
AVIATION...JOH
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
AREA FORECAST DISCUSSION
NWS SPOKANE WA
407 PM PST Sat Dec 8 2012
.SYNOPSIS...
Clearing skies tonight with a cool and dry air mass will bring
frosty morning temperatures Sunday. A cool and active early
winter weather pattern will bring a series of relatively weak
weather systems through the upcoming week...each capable of
producing relatively minor accumulations of snow.
&&
.DISCUSSION...
Quick update to the forecast, mainly to add more potential fog to
the northern valleys. Surface dew point analysis shows that while
the Spokane/CdA area has mid-teens dew points, the northern
valleys have mid-20s dew points with some areas of clear skies.
Fog should form rapidly in these areas in the next few hours.
Whether it can last the night is a more difficult call. Went with
patchy fog for the rest of the night and Sunday morning hours but
confidence in this is low.
Afternoon weather balloon showed very air above the surface, which
argues against much fog or low clouds tonight. This is also drier
than what the 18Z models expected. But they show a surge of low
level moisture from the south later tonight in response to
southerly winds ahead of the next weather system. 22Z RAP model
shows the same idea. Will check out 00Z runs before I make any
more changes to the forecast in this regard.
Temperatures will be cold tonight. Have to adjust Deer Park
downward significantly. RJ
&&
.AVIATION...
00Z TAFS: A mean northwesterly flow over the region will continue
to spread some middle and high clouds across the Inland Northwest,
with some localized MVFR stratocu toward the WA/ID border. Low
pressure approaching overnight into Sunday is expected to
gradually turn lower level flow toward the southeast. With a
modest temperatures and dew point spread around sunset Saturday
evening but the potential for effective radiational cooling in the
less dense middle and higher clouds brings the thought of stratus
and/or fog. The lower level atmosphere is relatively dry and these
features are not expected to be widespread. However all guidance
is showing some moisture creeping up the Palouse toward the
KGEG-KCOE area toward morning with the increase low level
southeast flow. While confidence is only fair, I have added some
MVFR stratus to this region for at least a brief period around
Sunday morning. As the system moves in late in the day, expected
thickening clouds from the west. A few flurries or a brief snow
shower may develop before 00Z Monday, however the risk is slight.
/J. Cote`
&&
.PREV DISCUSSION... /ISSUED 347 PM PST Sat Dec 8 2012/
SYNOPSIS...
Clearing skies tonight with a cool and dry air mass will bring
frosty morning temperatures Sunday. A cool and active early
winter weather pattern will bring a series of relatively weak
weather systems through the upcoming week...each capable of
producing relatively minor accumulations of snow.
DISCUSSION...
Tonight through Sunday...North/northwest flow aloft has developed
over the forecast area under the eastern flank of a broad eastern
Pacific ridge. Models are in good general agreement depicting a
flattening of this flow to a more west/northwest direction on
Sunday. Satellite imagery depicts this northerly flow but also
indicates this is a rather dirty ridge with plenty of at least mid
and high altitude moisture associated with the polar jet axis
diving down this ridge flank. At the surface high pressure over
the Canadian prairie is providing a shot of dry low level
continental air into the forecast area. The combination of this
dry low level air ans increasing subsidence aloft under the ridge
should allow a clear and frost night to evolve with good
radiational cooling conditions especially at snow covered
locations. Current lingering orographic snow showers will minor out
overnight.
On Sunday models are in decent agreement in in transiting an weak
mid level disturbance through the flow from wet to east across
the forecast area during the day. A lack of dynamic support and
with an anemic moisture feed in this traditionally dry flow regime
will cause this wave to weaken further as it crosses the region
during the day Sunday. While scattered snow showers will probably
result over the northern tier high terrain...and a few flurries
are possible over the northern basin...there is no compelling
reason to expect any significant accumulations from this feature.
Sunday will likely be another seasonably cool day of increasing
clouds with most of the light precipitation threat (snow...not rain)
over the northern mountains...Idaho Panhandle mountains and
Cascades higher terrain. /Fugazzi
Sunday night through Tuesday: A strong ridge offshore will keep a
dominant northwest flow across the Inland Northwest through early
next week. With the departure of the upper level trough, gradual
warming will be underway as a weak warm front pushes through
region late Sunday night into Monday morning. In the wake of the
front, low level moisture will be difficult to scrub out and
sounding profiles show the small chance of freezing drizzle in the
northern valleys early Monday morning before the low clouds mix
out. Meanwhile, isentropic lift coupled with orographics will
bring another shot of snow to the Idaho panhandle especially for
the central Panhandle mountains and the Camas Prairie, where there
is the potential for snow advisory amounts Sunday night through
Monday morning. Drier air will move across the region allowing the
snow showers to taper off over north Idaho by Monday afternoon.
This will be short lived as the next warm front reaches the region
from the north late Monday night, followed by an occluded front
sliding across the region on Tuesday. This will bring another good
shot of snow to much of the northern and Panhandle mountains.
Enough west to northwest flow will keep a rain shadow in the lee
of the Cascades into the western Basin. Meanwhile a wintry mix is
possible across the eastern Columbia Basin and Palouse on Tuesday
morning, before the front slides through and changes precipitation
types to valley rain and mountain snow by Tuesday afternoon.
Temperatures will be moderating slightly above seasonal normals by
Tuesday. /rfox.
Tuesday night through Thursday: The Inland Northwest will remain
in a northwest flow and in the path of systems dropping in from
the Gulf of Alaska. An amplified and relatively strong system
drops into the western United States Tuesday night and Wednesday.
The brunt of the lift dives into Oregon and California, yet the
Inland Northwest gets it fair share. Regional 700-500mb omega
peaks at the beginning of this period between -3 to -11
microbars/second, along and ahead of the incoming cold front and
upper trough axis. The strongest of this lift is directed across
the southeast. This is accompanied by deep layer moisture, with
PWATs peaking between 110-140% of normal. These ingredients will
keep the threat of precipitation high across eastern third of
Washington and Idaho, as well as the Cascade crest in the onshore
flow, Tuesday evening. The focus shifts to the southeast third of
Washington and central and southern Panhandle overnight into
Wednesday as the cold front shifts southeast. Some drier air
invades the middle to upper levels of the atmosphere. Yet an
inverted surface trough/deformation axis extending from southeast
Idaho to the eastern Washington will help to focus the still
modest sfc-700mb moisture and continued high precipitation chances
over the eastern forecast area. Wednesday night into Thursday a
shortwave ridge builds in and the inverted surface trough and
precipitation will gradually weaken and peter out to that by
Thursday mainly light orographic snow showers linger around the
Panhandle through the Blue Mountains.
Milder air in advance of this system will generally favor snow
levels between 2000-3500 feet along and south of the I-90 corridor
Tuesday evening, while snow levels further north of here remain
between valley floors and 2000 feet. This supports snow or
rain/snow mix along the I-90 corridor northward and rain and
mountain snow south of I-90 early Tuesday evening. However from
late evening into Wednesday morning snow levels are expected to
drop. The primary rain/snow threat will shift to the southeast
third of Washington and lower Panhandle overnight and by Wednesday
cooling aloft will bring mainly a snow threat. Temperatures warm
to near freezing or a degree or two above by Wednesday afternoon,
potentially limiting any accumulations. However banding under the
inverted surface trough could allow for some modest snow rates and
at least light accumulations, or possibly more. Between Tuesday
night and Wednesday the area that may receive the most impacts
from snow would be the central Panhandle, higher Palouse and
southern portions of Spokane and Kootenai county. These details
are apt to wobble so stay tuned; but estimating snow amounts
suggest marginal snow amounts for a highlight.
Thursday night and Friday: The next shortwave system comes in
from the northwest. Models begin to diverge over the precise
timing and track and strength, but overall this system appears
weaker than the Tuesday night-Wednesday system. The frontal wave
occludes and stretches on approach Thursday evening and skims by
the region overnight into Friday. This will renew the threat of
precipitation throughout the region. The best threat will be over
the Cascades, with a secondary modest threat across the eastern
third of Washington and north Idaho, with the lee of the Cascades
and Basin once again finding a minimal threat. Precipitation
amounts will depend on the strength of the system and this will
come into better focus as models come into better agreement.
However precipitation is expected to be mainly in the form of snow
with the colder air brought in with the prior system. /J. Cote`
Saturday and Sunday...Another in a series of troughs will swing
through the Inland Northwest next weekend, with high chances
for additional mountain snow and valley rain and snow. A warm front
lifting north into at least the southern portions of Washington
may play havoc with which areas get rain and snow or just snow.
However, given this is the extended extended went with a general
trend, didn`t stray far from the previous forecast, which also matched
up well with our neighbors. Temperatures look to be right around
mid- December normals. ty
AVIATION...
00Z TAFS: A mean northwesterly flow over the region will continue
to spread some middle and high clouds across the Inland Northwest,
with some localized MVFR stratocu toward the WA/ID border. Low
pressure approaching overnight into Sunday is expected to
gradually turn lower level flow toward the southeast. With a
modest temperatures and dew point spread around sunset Saturday
evening but the potential for effective radiational cooling in the
less dense middle and higher clouds brings the thought of stratus
and/or fog. The lower level atmosphere is relatively dry and these
features are not expected to be widespread. However all guidance
is showing some moisture creeping up the Palouse toward the
KGEG-KCOE area toward morning with the increase low level
southeast flow. While confidence is only fair, I have added some
MVFR stratus to this region for at least a brief period around
Sunday morning. As the system moves in late in the day, expected
thickening clouds from the west. A few flurries or a brief snow
shower may develop before 00Z Monday, however the risk is slight.
/J. Cote`
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 18 32 24 33 28 35 / 10 10 40 10 20 60
Coeur d`Alene 16 32 23 34 29 34 / 10 20 50 20 20 60
Pullman 19 31 26 38 30 38 / 10 10 50 20 10 50
Lewiston 24 40 31 43 33 44 / 10 10 30 20 10 40
Colville 19 32 23 34 28 38 / 10 20 40 10 30 60
Sandpoint 17 33 24 31 27 35 / 10 20 70 20 50 60
Kellogg 16 28 23 32 29 33 / 10 20 80 50 40 70
Moses Lake 21 36 23 36 27 38 / 10 10 10 0 10 10
Wenatchee 24 37 25 37 27 39 / 10 10 10 10 10 10
Omak 19 32 20 34 23 34 / 10 10 10 10 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
803 PM CST SAT DEC 8 2012
.UPDATE...
CLEAR SKIES AND LIGHT WINDS EARLY THIS EVENING ALLOWING TEMPS TO
DROP QUICKLY TO BELOW FORECAST MINS. MADE UPDATE WITH THOUGHTS
THAT TEMPS WOULD REBOUND A BIT AS WINDS AND CLOUDS INCREASE
THROUGH THE NIGHT. RAP HAS NOT CAUGHT UP WITH THIS TREND YET. NO
CHANGES TO HEADLINES ATTM WITH SNOW NOW MOVING INTO WESTERN MN.
NEW NAM JUST ARRIVING.
TE
&&
.PREV DISCUSSION...ISSUED AT 538 PM CST SAT DEC 8 2012...
SYNOPSIS...SNOW TOMORROW...THEN QUIET WEATHER FOR THE START OF
THE WORK WEEK.
THE LARGE SCALE PATTERN ACRS NOAM WAS DOMINATED BY RIDGES NR BOTH
COASTS...WITH FAIRLY BROAD TROF OVER THE MIDDLE OF THE CONTINENT.
THAT GENERAL PATTERN WL CONT FOR THE FCST PERIOD...THOUGH THE
TREND WL BE FOR A LITTLE MORE SPLITTING OF THE FLOW WITHIN THE
BASE OF THE UPR TROF TO OCCUR DURING THE LATTER PART OF THE
PERIOD. THE MAIN WX MAKERS WL BE A SERIES OF MJR SHRTWVS/CYCLONES
MOVG THRU THE PATTERN. A FAIRLY SIG PCPN EVENT IS LIKELY WITH EACH
CYCLONE...RESULTING IN NR NORMAL AMNTS FOR THE PERIOD. TEMPS WL
LIKLEY END UP A LITTLE ABV NORMAL FOR THE PERIOD.
SHORT TERM...TONIGHT AND SUNDAY.
THE MAIN CONCERN DURING THIS PART OF THE FORECAST IS THE SYSTEM
THAT WILL BRING SNOW TO THE AREA STARTING SUNDAY MORNING.
ESPECIALLY SINCE GETTING THIS ONE WRONG COULD REFLECT POORLY ON
OUR OFFICE WITH GREEN BAY IN THE NATIONAL SPOTLIGHT.
A WEAK UPPER LEVEL RIDGE AND HIGH PRESSURE AT THE SURFACE WILL
MOVE EAST TONIGHT AND SUNDAY. AN UPPER LEVEL SHORT WAVE IS
EXPECTED TO MOVE INTO WISCONSIN DURING THE DAY ON SUNDAY. A
SURFACE LOW PRESSURE SYSTEM WAS FORECAST TO WEAKEN AS IT MOVES
ACROSS THE PLAINS BEFORE BEING ABSORBED BY THE LOW MOVING THROUGH
ILLINOIS. THE RESULTANT PRESSURE PATTERN HAS A LOW OVER SOUTHERN
LAKE MICHIGAN AT 00Z MONDAY WITH A TROUGH EXTENDING NORTHWEST INTO
NORTHERN MINNESOTA. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE
LEFT EXIT REGION OF A JET MAX WILL HELP ENHANCE LIFT OVER THE
NORTHWEST PART OF THE FORECAST AREA DURING THE DAY ON SUNDAY.
HPC WINTER WEATHER ACCUMULATIONS SHOWED AN AREA OF 4 TO 6 INCHES
ACROSS PART OF NORTH CENTRAL WISCONSIN WITH 2 TO 4 INCHES COVERING
THE REST OF THE AREA FOR THE 24 HOUR PERIOD ENDING AT 00Z MONDAY.
THIS SEEMED PRETTY GOOD BASED ON MODEL QPF. MODEL TIMING
DIFFERENCES MADE THE FORECAST FOR THE START OF THE WINTER WEATHER
ADVISORY CHALLENGING. ENDED UP KEEPING 12Z FOR A START TIME IN THE
WEST AND 15Z FARTHER EAST. STORM SNOWFALL TOTALS COULD REACH
WARNING CRITERIA IF THE SNOW WERE TO FALL IN A 12 HOUR
PERIOD...BUT THINK ACCUMULATION WOULD BE OVER A LONGER PERIOD THAN
THAT.
LONG TERM...SUN NGT THRU NEXT SAT. CYCLONE WL BE CROSSING THE RGN
SUN NGT. UPR JET WL BE RIGHT ACRS THE AREA...SO THE SRN PART OF
THE FCST AREA MAY BE AFFECTED BY UPR/MID-LVL DRY SLOT. ALTHOUGH
THERMAL PROFILES WL BE COLD ENOUGH FOR SNOW...LACK OF SEEDING OF
THE LOWER CLDS WITH ICE CRYSTALS WL PROBABLY LEAD TO SOME DZ/FZDZ
/DEPENDING ON SFC TEMPS/ ACRS E-C AND MAYBE C WI DURING THE
EVENING. THAT COULD LINGER PAST MIDNIGHT...BUT MID-LVL MOISTURE FM
REMNANTS OF COMMA HEAD SHOULD SWING BACK SE ACRS THE AREA DURING
THE NGT...SO KEPT PCPN LATER IN THE NGT AS SHSN.
LAKE-EFFECT POTENTIAL FOR THE LAKE-SUPERIOR SNOWBELT IS SOMEWHAT
MUDDLED. FLOW WL PROBABLY BECOME TOO ELY FOR A TIME. THEN THE
WINDS WL SWING BACK ARND THROUGH A MORE FAVORABLE DIRECTION...BUT
CONT BACKING AND PROBABLY BECOME LGT BY LATE MON. AT THIS POINT
OPTED TO FOCUS THE HEADLINE ON THE SYSTEM SNOWS...AND FOREGO
EXTENDING IT TO COVER THE POSSIBLE SHORT-LIVED LAKE-EFFECT EVENT
MONDAY.
TEMPS ALSO TRICKY. NOT ANTICIPATING THAT A LOT OF CLEARING WL BE
ABLE TO OCCUR BEFORE THE SFC RIDGE WORKS INTO THE RGN. IN
ADDITION...THE STRONGEST SURGE OF THE COLDER AIR FLOWING SWD IN
THE WAKE OF THE DEPARTING SYSTEM WL BE S AND W OF THE FCST AREA.
SO WITH THE EXPECTATION OF HAVING PLENTY OF CLDS AND ONLY WK
CAA...RAISED TEMPS FOR THE NEXT SEVERAL PERIODS...ESP AT NGT. OF
COURSE IF WE WERE TO SOMEHOW CLEAR OUT AND HAVE LGT WINDS WITH THE
FRESH SNOW COVER...TEMPS COULD EASILY DROP 20+ F DEGREES BELOW
FCST MINS. BUT THE CHC OF THAT HAPPENING JUST DOES NOT SEEM GREAT
ENOUGH TO EVEN HEDGE THE FCST IN THAT DIRECTION.
THE NEXT MAJOR SYSTEM HEADING NEWD OUT OF THE PLAINS WL PROBABLY
ARRIVE NEXT WEEKEND.
&&
.AVIATION...VFR CONDITIONS TO CONTINUE THROUGH THE NIGHT...WITH
HIGH AND MID CLOUDS OVERTAKING THE SKY. INCOMING LOW PRESSURE WILL
BRING SNOW TO THE AREA BEGINNING SUN MORN. EXPECT RAPID
DETERIOATION OF CIGS AND VSBY WITH SNOW. ACCUMULATING SNOW AND
GUSTY EAST WINDS EXPECTED AT ALL TAF SITES THROUGH SUN AFTN.
TE
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 AM SUNDAY TO 6 AM CST MONDAY FOR
WIZ005-010-011-018-019-030-035-036.
WINTER WEATHER ADVISORY FROM 9 AM SUNDAY TO 6 AM CST MONDAY FOR
WIZ012-013-020-021-031-037-045-073-074.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1035 PM MST SAT DEC 8 2012
.UPDATE...
ISSUED AT 1000 PM MST SAT DEC 8 2012
AT 10 PM DROPPED THE WARNINGS FOR ZONE 4 AND 13, THE ADVISORY FOR
ZONE 5 AND ADDED A LOW END ADVISORY FOR ZONE 8 WHERE THE ROADS
THROUGH GLENWOOD CANYON TO AVON APPEAR TO BE A MESS.
THE COLD FRONT IS THROUGH THE I-70 CORRIDOR APPROACHING GUNNISON
AND TELLURIDE AT 9PM. GOOD SNOWFALL IS OCCURRING FROM GLENWOOD
CANYON TO VAIL PASS AND ALSO IN THE ROARING FORK.
SNOW HAS STOPPED FROM STEAMBOAT SPRINGS NORTHWARD IN THE NEW COLD
DRY AIR MASS. SNOW AMOUNTS IN THE PARK RANGE ARE 1-7 INCHES WITH
COLUMBINE PASS RECEIVING 9 INCHES. WINDS GUSTED INTO THE 50-57MPH
RANGE WITH THE FRONT THIS AFTERNOON BUT ARE ONLY IN THE 20S NOW.
THE CENTRAL MOUNTAINS SO FAR HAVE RECEIVED GENERALLY 2-3 INCHES
ON THE GRAND MESA, 4-5 INDEPENDENCE AND SCHOFIELD PASSES. SOUTHERN
MTNS TRACE TO 3 INCHES.
THE 00Z NAM AND THE 02Z RAP SHOW 0-1 INCHES FOR THE MOUNTAINS
NORTH OF STEAMBOAT THROUGH SUNDAY. THE BEST FRONTAL FORCING AND
JET SUPPORT MOVE TO THE CONTINENTAL DIVIDE AND EAST AFTER
MIDNIGHT. THE NW SAN JUANS MAY GET 3-6 INCHES BUT THE SW SAN
JUANS WILL BE CLOSER TO 0-2 INCHES. THE GUNNISON BASIN WILL LIKELY
GET 0-1 BUT CERRO SUMMIT WILL LIKELY GET 2-5 INCHES.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 328 PM MST SAT DEC 8 2012
A STRONG COLD FRONT AND UPPER TROUGH WILL MOVE THROUGH THE AREA
TONIGHT THROUGH SUNDAY. THE BRUNT OF THE SYSTEM MOVED STEADILY
INTO NW CO AND NE UT LATE THIS AFTERNOON AND WILL MARCH SOUTH
THROUGHOUT THE NIGHT. A STRONG WIND BAND ALOFT WILL REMAIN OVER
MUCH OF WRN CO AND ERN UT ABOVE THE SURFACE FRONT...THUS GOOD
WESTERLY OROGRAPHICS ARE EXPECTED. THE WIND ADVY OVER THE CO NW
PLATEAU WILL CONTINUE TIL NIGHTFALL.
SATELLITE IMAGERY SHOWS INDICATIONS OF A JET MAX AND DEVELOPING
SHORTWAVE TROUGH DROPPING DOWN THE WEST SIDE OF THE STORM. IT
SHOULD MOVE AND CONTINUE DIGGING FROM ITS CURRENT POSITION OVER
NRN NV/SE OREGON INTO UT AND THEN THE FOUR CORNERS LATER TONIGHT.
THIS WILL SHIFT THE FOCUS FOR SNOWFALL TO THE SOUTHERN AND CENTRAL
MOUNTAINS. THE WINTER WEATHER ADVISORY FOR THE NORTHERN CO MTNS WAS
UPGRADED TO A WARNING BECAUSE OF THE OROGRAPHIC ENHANCEMENT
EXPECTED. A SNOW ADVY WAS ADDED FOR MUCH OF THE CO CENTRAL AND
SOUTHERN MOUNTAINS ASSOCIATED WITH THE SECONDARY TROUGH EXPECTED
TO DIG IN TONIGHT. WINTER CONDITIONS SHOULD BEGIN DIMINISHING
NORTH OF I-70 LATE TONIGHT AS THE FRONT MOVES SOUTH. SNOWFALL
SHOULD DIMINISH SOUTH OF I-70 SUNDAY AFTERNOON AND EVENING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 328 PM MST SAT DEC 8 2012
THE GRADIENT WILL REMAIN TIGHT THROUGH MONDAY/MONDAY NIGHT AS THE
ROUGHLY NORTH-SOUTH ORIENTED JET PUSHES ANOTHER EMBEDDED COLD SHOT
ACROSS THE AREA. AT 500 MB -30C AIR IS PROGGED TO MOVE SOUTH OF
THE I-70 CORRIDOR MON EVENING INTO THE OVERNIGHT PERIOD. THE
COMBINATION OF THE COLD AIR ALOFT FOR REDUCED STABILITY...AND
STRONG OROGRAPHICS WILL PRODUCE ANOTHER ROUND OF SNOW OVER THE
FAVORED NORTHERN AND CENTRAL MOUNTAINS...ESPECIALLY ALONG THE
DIVIDE. THE LIMITING FACTOR WILL BE THE AVAILABILITY OF MOISTURE
WITH GENERALLY LESS THAN 2 G/KG. HOWEVER AT THESE TEMPERATURES IT
WILL NOT TAKE MUCH TO PRODUCE WIDESPREAD...BUT GENERALLY LIGHT
SNOW ALONG THE NORTHWEST FACING SLOPES. ON THE PLUS
SIDE...FORECAST SOUNDINGS DO INDICATE THAT THE DENDRITIC GROWTH
REGION WILL BECOME SATURATED BY MONDAY AFTERNOON IN THE STEAMBOAT
AND ASPEN AREAS...AND REMAIN SATURATED OVERNIGHT.
SNOW WILL DIMINISH BY MIDDAY ON TUE...WITH TEMPERATURES BEGINNING TO
MODIFY A LITTLE. THE PATTERN REMAINS PROGRESSIVE WITH A SHORTWAVE
RIDGE MOVING ACROSS THE REGION TUE NIGHT INTO WED. THE FLOW BECOMES
SOUTHWEST BY WED AFTERNOON AS THE NEXT LOW PRESSURE SYSTEM DIGS
ALONG THE COAST. THESE PERIODS WILL BE DRY AND WARMER DUE TO WAA
FROM THE SOUTHWEST.
MODELS SHOW THAT THE WESTERN LOW PRESSURE SYSTEM WILL SPLIT AS IT DROPS
ALONG THE COAST WED/WED NIGHT AND INTO THE GREAT BASIN ON THU. THIS
SYSTEM HAS THE POTENTIAL TO FAVOR THE SOUTHERN MOUNTAINS AS THE
SPLIT LOW TRACKS FROM THE GREAT BASIN EASTWARD. HOWEVER THERE IS
STILL QUITE A BIT OF UNCERTAINTY. THE ECMWF SHOWS A CLOSED LOW OVER
THE FOUR CORNERS EARLY FRI. THE GFS SHOWS MORE OF A TWO PRONGED OPEN
DISTURBANCE WITH THE FIRST IMPULSE THU NIGHT...AND THE SECOND FRI
NIGHT. THE GFS TRACK IS A LITTLE FARTHER NORTH AS WELL...WITH A
SLIGHT CHANCE OF PRECIPITATION INTO SAT.
TEMPERATURES SHOULD CLIMB ABOVE NORMAL WED AND THU...THEN FALL BELOW
NORMAL AGAIN BEHIND THE TROUGH AXIS ON FRI AND SAT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 920 PM MST SAT DEC 8 2012
AT 04Z THE COLD FRONT WAS THROUGH THE I-70 CORRIDOR AND
APPROACHING HIGHWAY 50. IT WILL WORK THROUGH THE REMAINDER OF
WESTERN COLORADO AND EASTERN UTAH BEFORE 12Z. SHSN HAVE BECOME
ISOLATED ALONG AND NORTH OF KVEL KHDN KSBS. STILL LOW CLOUD
CEILINGS LINGER WITH MTN OBSCURATIONS LIKELY THROUGH 14Z.
SHSN WITH MVFR/IFR CIGS AND VSBY WILL CONTINUE FOR KEGE AND KASE
THROUGH 10Z THEN IMPROVING INTO THE MORNING. KRIL WILL SEE
OCCASIONAL MVFR CIGS WITH SHSN TO THE EAST OF THAT AIRPORT. KGJT
AND KMTJ ARE IN VFR CONDITIONS WELL WEST OF THE ACTION. EXPECT MTN
OBSCURATIONS THROUGH 15Z FOR ALL MTNS EAST OF A LINE FROM KGJT TO
KCEZ.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 3 PM MST SUNDAY FOR COZ012-018-019.
WINTER WEATHER ADVISORY UNTIL 8 AM MST SUNDAY FOR COZ004-008-009-
013-014-017.
WINTER STORM WARNING UNTIL 8 AM MST SUNDAY FOR COZ010.
UT...NONE.
&&
$$
UPDATE...JOE
SHORT TERM...CC/PF
LONG TERM...EH
AVIATION...JOE
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1004 PM MST SAT DEC 8 2012
.UPDATE...
ISSUED AT 1000 PM MST SAT DEC 8 2012
AT 10 PM DROPPED THE WARNINGS FOR ZONE 4 AND 13, THE ADVISORY FOR
ZONE 5 AND ADDED A LOW END ADVISORY FOR ZONE 8 WHERE THE ROADS
THROUGH GLENWOOD CANYON TO AVON APPEAR TO BE A MESS.
THE COLD FRONT IS THROUGH THE I-70 CORRIDOR APPROACHING GUNNISON
AND TELLURIDE AT 9PM. GOOD SNOWFALL IS OCCURRING FROM GLENWOOD
CANYON TO VAIL PASS AND ALSO IN THE ROARING FORK.
SNOW HAS STOPPED FROM STEAMBOAT SPRINGS NORTHWARD IN THE NEW COLD
DRY AIR MASS. SNOW AMOUNTS IN THE PARK RANGE ARE 1-7 INCHES WITH
COLUMBINE PASS RECEIVING 9 INCHES. WINDS GUSTED INTO THE 50-57MPH
RANGE WITH THE FRONT THIS AFTERNOON BUT ARE ONLY IN THE 20S NOW.
THE CENTRAL MOUNTAINS SO FAR HAVE RECEIVED GENERALLY 2-3 INCHES
ON THE GRAND MESA, 4-5 INDEPENDENCE AND SCHOFIELD PASSES. SOUTHERN
MTNS TRACE TO 3 INCHES.
THE 00Z NAM AND THE 02Z RAP SHOW 0-1 INCHES FOR THE MOUNTAINS
NORTH OF STEAMBOAT THROUGH SUNDAY. THE BEST FRONTAL FORCING AND
JET SUPPORT MOVE TO THE CONTINENTAL DIVIDE AND EAST AFTER
MIDNIGHT. THE NW SAN JUANS MAY GET 3-6 INCHES BUT THE SW SAN
JUANS WILL BE CLOSER TO 0-2 INCHES. THE GUNNISON BASIN WILL LIKELY
GET 0-1 BUT CERRO SUMMIT WILL LIKELY GET 2-5 INCHES.
STILL CONTEMPLATING HOW TO HANDLE THE STRONG-LEANING HIGHLIGHTS
THAT ARE CURRENTLY IN EFFECT. COORDINATED WITH CYS TO LOWER THE
WARNING OVER ZONE 4. ZONE 5 STEAMBOAT ALSO SEEMS TO BE DONE WITH
SIGNIFICANT SNOW ACCUMULATION.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 328 PM MST SAT DEC 8 2012
A STRONG COLD FRONT AND UPPER TROUGH WILL MOVE THROUGH THE AREA
TONIGHT THROUGH SUNDAY. THE BRUNT OF THE SYSTEM MOVED STEADILY
INTO NW CO AND NE UT LATE THIS AFTERNOON AND WILL MARCH SOUTH
THROUGHOUT THE NIGHT. A STRONG WIND BAND ALOFT WILL REMAIN OVER
MUCH OF WRN CO AND ERN UT ABOVE THE SURFACE FRONT...THUS GOOD
WESTERLY OROGRAPHICS ARE EXPECTED. THE WIND ADVY OVER THE CO NW
PLATEAU WILL CONTINUE TIL NIGHTFALL.
SATELLITE IMAGERY SHOWS INDICATIONS OF A JET MAX AND DEVELOPING
SHORTWAVE TROUGH DROPPING DOWN THE WEST SIDE OF THE STORM. IT
SHOULD MOVE AND CONTINUE DIGGING FROM ITS CURRENT POSITION OVER
NRN NV/SE OREGON INTO UT AND THEN THE FOUR CORNERS LATER TONIGHT.
THIS WILL SHIFT THE FOCUS FOR SNOWFALL TO THE SOUTHERN AND CENTRAL
MOUNTAINS. THE WINTER WEATHER ADVISORY FOR THE NORTHERN CO MTNS WAS
UPGRADED TO A WARNING BECAUSE OF THE OROGRAPHIC ENHANCEMENT
EXPECTED. A SNOW ADVY WAS ADDED FOR MUCH OF THE CO CENTRAL AND
SOUTHERN MOUNTAINS ASSOCIATED WITH THE SECONDARY TROUGH EXPECTED
TO DIG IN TONIGHT. WINTER CONDITIONS SHOULD BEGIN DIMINISHING
NORTH OF I-70 LATE TONIGHT AS THE FRONT MOVES SOUTH. SNOWFALL
SHOULD DIMINISH SOUTH OF I-70 SUNDAY AFTERNOON AND EVENING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 328 PM MST SAT DEC 8 2012
THE GRADIENT WILL REMAIN TIGHT THROUGH MONDAY/MONDAY NIGHT AS THE
ROUGHLY NORTH-SOUTH ORIENTED JET PUSHES ANOTHER EMBEDDED COLD SHOT
ACROSS THE AREA. AT 500 MB -30C AIR IS PROGGED TO MOVE SOUTH OF
THE I-70 CORRIDOR MON EVENING INTO THE OVERNIGHT PERIOD. THE
COMBINATION OF THE COLD AIR ALOFT FOR REDUCED STABILITY...AND
STRONG OROGRAPHICS WILL PRODUCE ANOTHER ROUND OF SNOW OVER THE
FAVORED NORTHERN AND CENTRAL MOUNTAINS...ESPECIALLY ALONG THE
DIVIDE. THE LIMITING FACTOR WILL BE THE AVAILABILITY OF MOISTURE
WITH GENERALLY LESS THAN 2 G/KG. HOWEVER AT THESE TEMPERATURES IT
WILL NOT TAKE MUCH TO PRODUCE WIDESPREAD...BUT GENERALLY LIGHT
SNOW ALONG THE NORTHWEST FACING SLOPES. ON THE PLUS
SIDE...FORECAST SOUNDINGS DO INDICATE THAT THE DENDRITIC GROWTH
REGION WILL BECOME SATURATED BY MONDAY AFTERNOON IN THE STEAMBOAT
AND ASPEN AREAS...AND REMAIN SATURATED OVERNIGHT.
SNOW WILL DIMINISH BY MIDDAY ON TUE...WITH TEMPERATURES BEGINNING TO
MODIFY A LITTLE. THE PATTERN REMAINS PROGRESSIVE WITH A SHORTWAVE
RIDGE MOVING ACROSS THE REGION TUE NIGHT INTO WED. THE FLOW BECOMES
SOUTHWEST BY WED AFTERNOON AS THE NEXT LOW PRESSURE SYSTEM DIGS
ALONG THE COAST. THESE PERIODS WILL BE DRY AND WARMER DUE TO WAA
FROM THE SOUTHWEST.
MODELS SHOW THAT THE WESTERN LOW PRESSURE SYSTEM WILL SPLIT AS IT DROPS
ALONG THE COAST WED/WED NIGHT AND INTO THE GREAT BASIN ON THU. THIS
SYSTEM HAS THE POTENTIAL TO FAVOR THE SOUTHERN MOUNTAINS AS THE
SPLIT LOW TRACKS FROM THE GREAT BASIN EASTWARD. HOWEVER THERE IS
STILL QUITE A BIT OF UNCERTAINTY. THE ECMWF SHOWS A CLOSED LOW OVER
THE FOUR CORNERS EARLY FRI. THE GFS SHOWS MORE OF A TWO PRONGED OPEN
DISTURBANCE WITH THE FIRST IMPULSE THU NIGHT...AND THE SECOND FRI
NIGHT. THE GFS TRACK IS A LITTLE FARTHER NORTH AS WELL...WITH A
SLIGHT CHANCE OF PRECIPITATION INTO SAT.
TEMPERATURES SHOULD CLIMB ABOVE NORMAL WED AND THU...THEN FALL BELOW
NORMAL AGAIN BEHIND THE TROUGH AXIS ON FRI AND SAT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 920 PM MST SAT DEC 8 2012
AT 04Z THE COLD FRONT WAS THROUGH THE I-70 CORRIDOR AND
APPROACHING HIGHWAY 50. IT WILL WORK THROUGH THE REMAINDER OF
WESTERN COLORADO AND EASTERN UTAH BEFORE 12Z. SHSN HAVE BECOME
ISOLATED ALONG AND NORTH OF KVEL KHDN KSBS. STILL LOW CLOUD
CEILINGS LINGER WITH MTN OBSCURATIONS LIKELY THROUGH 14Z.
SHSN WITH MVFR/IFR CIGS AND VSBY WILL CONTINUE FOR KEGE AND KASE
THROUGH 10Z THEN IMPROVING INTO THE MORNING. KRIL WILL SEE
OCCASIONAL MVFR CIGS WITH SHSN TO THE EAST OF THAT AIRPORT. KGJT
AND KMTJ ARE IN VFR CONDITIONS WELL WEST OF THE ACTION. EXPECT MTN
OBSCURATIONS THROUGH 15Z FOR ALL MTNS EAST OF A LINE FROM KGJT TO
KCEZ.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 3 PM MST SUNDAY FOR COZ012-018-019.
WINTER WEATHER ADVISORY UNTIL 8 AM MST SUNDAY FOR COZ004-008-009-
013-014-017.
WINTER STORM WARNING UNTIL 8 AM MST SUNDAY FOR COZ010.
UT...NONE.
&&
$$
UPDATE...JOE
SHORT TERM...CC/PF
LONG TERM...EH
AVIATION...JOE
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
921 PM MST SAT DEC 8 2012
.UPDATE...
ISSUED AT 920 PM MST SAT DEC 8 2012
THE COLD FRONT IS THROUGH THE I-70 CORRIDOR APPROACHING GUNNISON
AND TELLURIDE AT 9PM. GOOD SNOWFALL IS OCCURRING FROM GLENWOOD
CANYON TO VAIL PASS AND ALSO IN THE ROARING FORK.
SNOW HAS STOPPED FROM STEAMBOAT SPRINGS NORTHWARD IN THE NEW COLD
DRY AIR MASS. SNOW AMOUNTS IN THE PARK RANGE ARE 1-7 INCHES WITH
COLUMBINE PASS RECEIVING 9 INCHES. WINDS GUSTED INTO THE 50-57MPH
RANGE WITH THE FRONT THIS AFTERNOON BUT ARE ONLY IN THE 20S NOW.
THE CENTRAL MOUNTAINS SO FAR HAVE RECEIVED GENERALLY 2-3 INCHES
ON THE GRAND MESA, 4-5 INDEPENDENCE AND SCHOFIELD PASSES. SOUTHERN
MTNS TRACE TO 3 INCHES.
THE 00Z NAM AND THE 02Z RAP SHOW 0-1 INCHES FOR THE MOUNTAINS
NORTH OF STEAMBOAT THROUGH SUNDAY. THE BEST FRONTAL FORCING AND
JET SUPPORT MOVE TO THE CONTINENTAL DIVIDE AND EAST AFTER
MIDNIGHT. THE NW SAN JUANS MAY GET 3-6 INCHES BUT THE SW SAN
JUANS WILL BE CLOSER TO 0-2 INCHES. THE GUNNISON BASIN WILL LIKELY
GET 0-1 BUT CERRO SUMMIT WILL LIKELY GET 2-5 INCHES.
STILL CONTEMPLATING HOW TO HANDLE THE STRONG-LEANING HIGHLIGHTS
THAT ARE CURRENTLY IN EFFECT. COORDINATED WITH CYS TO LOWER THE
WARNING OVER ZONE 4. ZONE 5 STEAMBOAT ALSO SEEMS TO BE DONE WITH
SIGNIFICANT SNOW ACCUMULATION.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 328 PM MST SAT DEC 8 2012
A STRONG COLD FRONT AND UPPER TROUGH WILL MOVE THROUGH THE AREA
TONIGHT THROUGH SUNDAY. THE BRUNT OF THE SYSTEM MOVED STEADILY
INTO NW CO AND NE UT LATE THIS AFTERNOON AND WILL MARCH SOUTH
THROUGHOUT THE NIGHT. A STRONG WIND BAND ALOFT WILL REMAIN OVER
MUCH OF WRN CO AND ERN UT ABOVE THE SURFACE FRONT...THUS GOOD
WESTERLY OROGRAPHICS ARE EXPECTED. THE WIND ADVY OVER THE CO NW
PLATEAU WILL CONTINUE TIL NIGHTFALL.
SATELLITE IMAGERY SHOWS INDICATIONS OF A JET MAX AND DEVELOPING
SHORTWAVE TROUGH DROPPING DOWN THE WEST SIDE OF THE STORM. IT
SHOULD MOVE AND CONTINUE DIGGING FROM ITS CURRENT POSITION OVER
NRN NV/SE OREGON INTO UT AND THEN THE FOUR CORNERS LATER TONIGHT.
THIS WILL SHIFT THE FOCUS FOR SNOWFALL TO THE SOUTHERN AND CENTRAL
MOUNTAINS. THE WINTER WEATHER ADVISORY FOR THE NORTHERN CO MTNS WAS
UPGRADED TO A WARNING BECAUSE OF THE OROGRAPHIC ENHANCEMENT
EXPECTED. A SNOW ADVY WAS ADDED FOR MUCH OF THE CO CENTRAL AND
SOUTHERN MOUNTAINS ASSOCIATED WITH THE SECONDARY TROUGH EXPECTED
TO DIG IN TONIGHT. WINTER CONDITIONS SHOULD BEGIN DIMINISHING
NORTH OF I-70 LATE TONIGHT AS THE FRONT MOVES SOUTH. SNOWFALL
SHOULD DIMINISH SOUTH OF I-70 SUNDAY AFTERNOON AND EVENING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 328 PM MST SAT DEC 8 2012
THE GRADIENT WILL REMAIN TIGHT THROUGH MONDAY/MONDAY NIGHT AS THE
ROUGHLY NORTH-SOUTH ORIENTED JET PUSHES ANOTHER EMBEDDED COLD SHOT
ACROSS THE AREA. AT 500 MB -30C AIR IS PROGGED TO MOVE SOUTH OF
THE I-70 CORRIDOR MON EVENING INTO THE OVERNIGHT PERIOD. THE
COMBINATION OF THE COLD AIR ALOFT FOR REDUCED STABILITY...AND
STRONG OROGRAPHICS WILL PRODUCE ANOTHER ROUND OF SNOW OVER THE
FAVORED NORTHERN AND CENTRAL MOUNTAINS...ESPECIALLY ALONG THE
DIVIDE. THE LIMITING FACTOR WILL BE THE AVAILABILITY OF MOISTURE
WITH GENERALLY LESS THAN 2 G/KG. HOWEVER AT THESE TEMPERATURES IT
WILL NOT TAKE MUCH TO PRODUCE WIDESPREAD...BUT GENERALLY LIGHT
SNOW ALONG THE NORTHWEST FACING SLOPES. ON THE PLUS
SIDE...FORECAST SOUNDINGS DO INDICATE THAT THE DENDRITIC GROWTH
REGION WILL BECOME SATURATED BY MONDAY AFTERNOON IN THE STEAMBOAT
AND ASPEN AREAS...AND REMAIN SATURATED OVERNIGHT.
SNOW WILL DIMINISH BY MIDDAY ON TUE...WITH TEMPERATURES BEGINNING TO
MODIFY A LITTLE. THE PATTERN REMAINS PROGRESSIVE WITH A SHORTWAVE
RIDGE MOVING ACROSS THE REGION TUE NIGHT INTO WED. THE FLOW BECOMES
SOUTHWEST BY WED AFTERNOON AS THE NEXT LOW PRESSURE SYSTEM DIGS
ALONG THE COAST. THESE PERIODS WILL BE DRY AND WARMER DUE TO WAA
FROM THE SOUTHWEST.
MODELS SHOW THAT THE WESTERN LOW PRESSURE SYSTEM WILL SPLIT AS IT DROPS
ALONG THE COAST WED/WED NIGHT AND INTO THE GREAT BASIN ON THU. THIS
SYSTEM HAS THE POTENTIAL TO FAVOR THE SOUTHERN MOUNTAINS AS THE
SPLIT LOW TRACKS FROM THE GREAT BASIN EASTWARD. HOWEVER THERE IS
STILL QUITE A BIT OF UNCERTAINTY. THE ECMWF SHOWS A CLOSED LOW OVER
THE FOUR CORNERS EARLY FRI. THE GFS SHOWS MORE OF A TWO PRONGED OPEN
DISTURBANCE WITH THE FIRST IMPULSE THU NIGHT...AND THE SECOND FRI
NIGHT. THE GFS TRACK IS A LITTLE FARTHER NORTH AS WELL...WITH A
SLIGHT CHANCE OF PRECIPITATION INTO SAT.
TEMPERATURES SHOULD CLIMB ABOVE NORMAL WED AND THU...THEN FALL BELOW
NORMAL AGAIN BEHIND THE TROUGH AXIS ON FRI AND SAT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 920 PM MST SAT DEC 8 2012
AT 04Z THE COLD FRONT WAS THROUGH THE I-70 CORRIDOR AND
APPROACHING HIGHWAY 50. IT WILL WORK THROUGH THE REMAINDER OF
WESTERN COLORADO AND EASTERN UTAH BEFORE 12Z. SHSN HAVE BECOME
ISOLATED ALONG AND NORTH OF KVEL KHDN KSBS. STILL LOW CLOUD
CEILINGS LINGER WITH MTN OBSCURATIONS LIKELY THROUGH 14Z.
SHSN WITH MVFR/IFR CIGS AND VSBY WILL CONTINUE FOR KEGE AND KASE
THROUGH 10Z THEN IMPROVING INTO THE MORNING. KRIL WILL SEE
OCCASIONAL MVFR CIGS WITH SHSN TO THE EAST OF THAT AIRPORT. KGJT
AND KMTJ ARE IN VFR CONDITIONS WELL WEST OF THE ACTION. EXPECT MTN
OBSCURATIONS THROUGH 15Z FOR ALL MTNS EAST OF A LINE FROM KGJT TO
KCEZ.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 3 PM MST SUNDAY FOR COZ012-018-019.
WINTER WEATHER ADVISORY UNTIL 8 AM MST SUNDAY FOR COZ009-014-017.
WINTER STORM WARNING UNTIL 8 AM MST SUNDAY FOR COZ004-010-013.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ005.
UT...NONE.
&&
$$
UPDATE...JOE
SHORT TERM...CC/PF
LONG TERM...EH
AVIATION...JOE
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1138 PM CST SAT DEC 8 2012
.UPDATE...
ADDED 06Z TAF DISCUSSION.
NO BIG CHANGES WITH EVENING UPDATE BUT HAVE NUDGED UP THE SNOW
AMOUNTS NE IN THE MASON CITY AND WATERLOO AREAS. SMALL AREA OF
PRECIP THAT MOVED THROUGH CENTRAL IA RECENTLY WAS MAINLY RAIN AT THE
AIRPORT...BUT PRIMARILY SNOW JUST TO THE NORTH HERE AT THE
OFFICE...AT BOONE AND AMES. MAINLY MELTED BUT JUST STUCK A LITTLE
IN SOME AREAS. EXPECT THIS TO CONTINUE AS IT WORKS NE LATER TONIGHT
AS 02Z RAP 2.5KM LAYER MAX WET BULB TEMP CHANGES LITTLE OVERNIGHT.
THIS SUGGESTS CURRENT SNOW AND RAIN/SNOW LINES ARE A TAD TOO FAR
NORTH AND HAVE SHIFTED THEM A BIT SOUTHWARD RESULTING IN A HALF INCH
OR MORE INCREASE IN SNOW AMOUNTS THERE. LATEST NAM...DEV HRRR AND
WRF RUNS ALL SUGGEST LOBE OF FORCING CURRENTLY PRODUCING PRECIP FROM
SW MN INTO IA WILL FURTHER SATURATE AND THEN PHASE WITH MATURING
SERN IA PRECIP WITH MORE WIDESPREAD COVERAGE OVER NERN IA TOWARD
DAYBREAK.
&&
.SHORT TERM /TONIGHT/...
BAND OF STRONG THETA-E ADVECTION IS MOVING INTO WESTERN IOWA THIS
AFTERNOON AND WILL CONTINUE TO MOVE ACROSS THE STATE THIS EVENING.
RADAR ECHOES HAVE BEEN INTENSIFYING WITH THIS MID LEVEL FORCING FROM
SOUTHWEST IOWA THROUGH SOUTHEAST SOUTH DAKOTA AND AT THIS
TIME...ONLY PRECIPITATION REPORTS ARE FROM THE NORTHERN EDGE WITH
CLOUD HEIGHTS REMAINING AOA 7KFT FARTHER SOUTH. EXPECT SOME LIGHT
PRECIPITATION TO FALL OVER THE NORTHWEST THIRD TO HALF THIS EVENING
ALONG THE INITIAL MOISTURE SURGE. SOME OF THIS PRECIPITATION COULD
BE LIGHT SNOW GIVEN WETBULB PROFILES AS FAR SOUTH AS HIGHWAY 30
THOUGH NO ACCUMULATIONS ARE EXPECTED THIS EVENING EXCEPT FOR
POSSIBLY THE FAR NORTH. A SECONDARY THETA-E SURGE WILL FOLLOW AFTER
MIDNIGHT. THIS WILL HELP KEEP LOW LEVEL TEMPERATURES ABOVE FREEZING
OVER THE CENTRAL AND SOUTH AND KEEP WETBULBS IN THE LOWEST
1500-2500FT 34F OR HIGHER. THIS LAYER WILL BE ENOUGH TO MELT ANY
SNOW THROUGH THIS REGION. COLDER PROFILES YET NORTH WHERE
PRECIPITATION WILL BE EXPANDING WITH THE ARRIVAL OF INCREASING
KINEMATICS WITH THE APPROACH OF THE UPPER LEVEL SHORT WAVE. THE
PRECIPITATION WILL BE ALL SNOW OVER THE NORTH. EXPECT SEASONAL TO
SLIGHTLY HIGHER SNOW RATIOS OVER THE NORTH OF 13-15 TO 1 AND COULD
HAVE ACCUMULATIONS BY 12Z OF 0.5 TO 1.5 INCHES ALONG AND NORTH OF A
DENISON TO FORT DODGE TO WAVERLY LINE. NON-DIURNAL TEMPERATURE
TRENDS OVERNIGHT WITH HIGHER DEWPOINTS MOVING INTO THE STATE.
.LONG TERM /SUNDAY THROUGH FRIDAY/...
THERE ARE TWO SYSTEMS TO FOCUS ON IN THE EXTENDED. THE FIRST IS THE
SYSTEM FROM TONIGHT THAT WILL BE QUICKLY PUSHING ACROSS THE CWA
DURING THE MORNING HOURS FOLLOWED BY STRONG COLD ADVECTION.
SOUNDINGS AT 12Z SHOW TEMPERATURES AT OR JUST ABOVE FREEZING ACROSS
THE FORECAST AREA. A COLD FRONT WILL SWEEP THE CWA THROUGH THE
MORNING AND SOUNDING LOCATIONS WEST OF I-35 DRY OUT BEHIND THE FRONT
WITH TEMPERATURES FALLING THROUGHOUT THE LATE MORNING AND THE REST
OF THE DAY. FORCING WEAKENS THROUGHOUT THE DAY BUT POCKETS OF
BETTER FORCING REMAIN ACROSS CENTRAL IOWA THROUGH MOST OF THE DAY.
THE PROBLEM IS THAT WE LOSE OUR DEEPER MOISTURE QUICKLY IN THE
MORNING. AS A RESULT...I AM NOT LOOKING FOR MUCH IN THE WAY OF
PRECIPITATION/SNOW ACCUMULATION OUT OF THIS SYSTEM. WE COULD SEE A
COUPLE OF INCHES ACROSS THE NORTH AT BEST WITH TRACE AMOUNTS
ELSEWHERE AS PRECIP TRANSITIONS TO SNOW BEFORE ENDING. THE SURFACE
LOW IS TOO FAR NORTH AND THE UPPER WAVE IS NOT DEEP ENOUGH TO DO
MUCH MORE THAN THAT. WINDS ON THE OTHER HAND MAY BE PROBLEMATIC
SUNDAY...ESPECIALLY COMBINED WITH THE COLD AIR MOVING IN. WIND
CHILLS WILL FALL INTO THE TEENS DURING THE AFTERNOON.
TUESDAY THROUGH THURSDAY...THERE WILL BE A LONG WAVE TROUGH PASSING
ACROSS THE REGION WITH A RIDGE BUILDING INTO THE WEST TUESDAY AND
SHIFTING ACROSS THE MIDWEST THROUGH THURSDAY AS A LARGE TROUGH
CARVES OUT OVER THE WEST. THIS WILL BE A PLAYER IN OUR WEATHER INTO
THE WEEKEND.
THEN LATER IN THE WEEK...IN THE FRIDAY TO SATURDAY NIGHT TIME FRAME
A SECOND POTENTIALLY STRONG SYSTEM WILL AFFECT CENTRAL IOWA. THERE
ARE SIGNIFICANT DIFFERENCES BETWEEN THE MODELS...AT LEAST INITIALLY
AS TO THE EVOLUTION OF THE UPPER LEVEL WAVE...THE SURFACE LOW AND
THE FRONTAL BOUNDARY WITH THE SYSTEM. THE GFS LEAVES THIS AN OPEN
WAVE THROUGH FRIDAY THEN DEVELOPS A LOW OVER SOUTH DAKOTA AS THE
SYSTEM WRAPS UP WHILE THE EURO DEVELOPS A DEEP LOW OVER KANSAS AND
LIFTS IT NORTHEAST. BOTH MODELS PUT THE UPPER LOW OVER SE MN AT 00Z
BUT HOW IT GETS THERE IS AN QUESTION. THE EURO DEVELOPS A MUCH
BETTER DEFORMATION ZONE OVER NORTHERN INTO WEST CENTRAL IOWA WHILE
THE GFS HAS THIS FURTHER NORTH.
THE SURFACE LOW POSITION IS ALSO QUITE DIFFERENT IN PLACEMENT AND
INTENSITY. BOTH MODELS POINT AT SOUTHERN IOWA AND LOCATIONS SOUTH
AND EAST BEING IN A WARM ADVECTION ZONE WITH PRETTY IMPRESSIVE CAPE
FOR MID DECEMBER. THEREFORE I HAD TO PUT IN ISOLATED THUNDER ACROSS
THE SOUTH. PTYPE ELSEWHERE IS VERY DIFFICULT TO PINPOINT AT THIS
POINT. THE NORTH INTO WEST CENTRAL COULD HAVE A MIXED BAG OF PRECIP
CHANGING TO SNOW AND ACCUMULATING. A RAIN/SNOW TRANSITION WILL
OCCUR BETWEEN THERE AND SOUTH BUT THERE IS NOT ENOUGH AGREEMENT
BETWEEN THE MODELS TO SAY WITH ANY CERTAINTY. AT THIS POINT IT
LOOKS MESSY WITH A POTENTIAL FOR SEVERAL PTYPES ACROSS IOWA AND
THUNDER SOUTH. HOWEVER THE MODELS DID SOMETHING SIMILAR WITH THIS
CURRENT SYSTEM AT THAT FAR OUT.
&&
.AVIATION...09/06Z
CONDITIONS HAVE DETERIORATED THIS EVENING AND NOW MAINLY VARY FROM
LIFR-MVFR. ALTHOUGH PATCHY LIGHT PRECIP WILL CONTINUE JUST AFTER
MIDNIGHT ADDITIONAL PRECIP IS EXPECTED DEVELOP AFTER 09Z IN
KMCW/KALO AREA...MAINLY IN THE FORM OF SNOW. ONCE THIS OCCURS MANY
LOCATIONS WILL LIKELY DIP TO LIFR OR AT LEAST IFR. PRECIP SHOULD
END 14-16Z FOLLOWED BY WINDS BECOMING NW WITH GUSTS INTO THE 20S
INTO THE AFTERNOON AND EVENING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE/AVIATION...SMALL
SHORT TERM...DONAVON
LONG TERM...FAB
AREA FORECAST DISCUSSION
NWS WICHITA KS
329 AM CST SUN DEC 9 2012
.DISCUSSION...
TODAY-THIS EVENING:
THE GUSTY NORTHWEST WINDS AND COLDEST AIR IS LAGGING BEHIND THE
INITIAL WIND SHIFT. PRECIPITATION SO FAR HAS BEEN EXTREMELY LIMITED
AND BASED ON LATEST MODEL RUNS...LOW LEVEL DRY AIR WILL LIKELY BE
TOUGH TO OVERCOME. HOWEVER BEST SATURATION/LIFT IN TRAILING BAND
FAIRLY IMPRESSIVE...BUT SO IS THE 10KFT OF DRY AIR BELOW IT. WHILE
LIGHT SNOW IS LIKELY ALOFT...BELIEVE IT WILL BE VERY DIFFICULT TO
GET MORE THAN SCATTERED FLURRIES TO THE GROUND. MID/UPPER LEVEL LIFT
ACTUALLY INCREASES A BIT TOWARDS 0000 UTC...AND WILL LINGER
FLURRIES UNTIL MIDNIGHT ACROSS EASTERN SECTIONS. TEMPERATURES WILL
GENERALLY FALL THROUGHOUT THE DAY WITH COLD AIR ADVECTION FROM THE
GUSTY NORTHWEST WINDS.
LATE TONIGHT:
TEMPERATURES WILL CONTINUE TO TUMBLE DURING THE NIGHT WITH CLEARING
SKIES AND DECREASING WINDS. MODEL OUTPUT STATISTICS GUIDANCE IN
GOOD AGREEMENT FOR SINGLE DIGITS FOR FAR NORTHWEST SECTIONS.
MON-SAT:
AFTER VERY CHILLY START TO MONDAY...EXPECT A GRADUAL MODERATION OF
THE COLD AIRMASS. SHORTWAVE MOVING THROUGH MIDWEEK STILL APPEARS TO
BE MOISTURE STARVED WITH ONLY SOME INCREASE IN CLOUDS. DECENT
WARMUP ANTICIPATED WITH COMBINATION OF DRY AIR AND FAVORABLE SW
FLOW AT H85 ON THU. MODELS HAVE DIVERGED WITH TRACK/TIMING OF
SYSTEM LATE IN THE WEEK. UNFORTUNATELY...OVERALL TREND HAS LOWER
CHANCES FOR PRECIPITATION ACROSS WESTERN HALF OF FORECAST AREA AS
SURFACE CYCLOGENSIS DEVELOPS DRY SLOT OVER MUCH OF THE FORECAST
AREA. BEST CHANCE STILL APPEARS TO BE IN SOUTHEAST KS. -HOWERTON
&&
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
LOW LEVEL ISENTROPIC LIFT FROM THE SOUTH-SOUTHWEST HAS LED TO
WIDESPREAD IFR CONDITIONS ACROSS THE REGION LATE THIS EVENING. BOTH
THE NAM/WRF AND GFS NOT HANDLING THIS LOW LEVEL MOISTURE VERY
WELL...WITH THE LATEST RUC40 CLOSER TO REALITY. THE CEILINGS EVEN
DROPPED LOWER THAN THE PESSIMISTIC RUC ON CEILINGS TO AROUND 6-9K FT
AGL.
EXPECT THE IFR CONDITIONS TO BE SHORT LIVED...AS A COLD FRONTAL
BOUNDARY LOOKS TO ARRIVE AFTER 08Z-09/SUN ACROSS CENTRAL
KANSAS...AND PLUNGE SOUTH ACROSS SOUTH CENTRAL KS AFTER 09-11Z/SUN.
THIS WILL LEAD TO CEILINGS BEGINNING TO RAPIDLY LIFT WITH MVFR/VFR
CEILINGS RETURNING BY THE MORNING HOURS ON SUN...AS LOW LEVELS
QUICKLY DRY OUT. WINDS BEHIND THE FRONT WILL INCREASE TO 20-30 KTS
WITH SOME LIGHT SNOW DEVELOPING ACROSS PORTIONS OF CENTRAL KANSAS
EARLY SUNDAY. NOT EXPECTING THE LIGHT SNOW TO RESTRICT VSBYS MUCH
WITH VFR CONDITIONS EXPECTED...AS THIS WILL BE MAINLY A LIGHT
SNOW/FLURRY EVENT.
KETCHAM
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 38 13 37 19 / 10 10 0 0
HUTCHINSON 35 11 37 21 / 10 10 0 0
NEWTON 35 12 35 20 / 10 10 0 0
ELDORADO 38 13 35 18 / 10 10 0 0
WINFIELD-KWLD 41 14 37 21 / 10 10 0 0
RUSSELL 33 4 37 19 / 10 0 0 0
GREAT BEND 33 7 37 22 / 20 0 0 0
SALINA 35 10 37 20 / 10 10 0 0
MCPHERSON 34 11 37 20 / 10 10 0 0
COFFEYVILLE 46 20 36 19 / 20 10 0 0
CHANUTE 43 16 34 18 / 20 10 0 0
IOLA 42 16 34 20 / 20 10 0 0
PARSONS-KPPF 44 17 35 16 / 20 10 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1139 PM CST SAT DEC 8 2012
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
LOW LEVEL ISENTROPIC LIFT FROM THE SOUTH-SOUTHWEST HAS LED TO
WIDESPREAD IFR CONDITIONS ACROSS THE REGION LATE THIS EVENING. BOTH
THE NAM/WRF AND GFS NOT HANDLING THIS LOW LEVEL MOISTURE VERY
WELL...WITH THE LATEST RUC40 CLOSER TO REALITY. THE CEILINGS EVEN
DROPPED LOWER THAN THE PESSIMISTIC RUC ON CEILINGS TO AROUND 6-9K FT
AGL.
EXPECT THE IFR CONDITIONS TO BE SHORT LIVED...AS A COLD FRONTAL
BOUNDARY LOOKS TO ARRIVE AFTER 08Z-09/SUN ACROSS CENTRAL
KANSAS...AND PLUNGE SOUTH ACROSS SOUTH CENTRAL KS AFTER 09-11Z/SUN.
THIS WILL LEAD TO CEILINGS BEGINNING TO RAPIDLY LIFT WITH MVFR/VFR
CEILINGS RETURNING BY THE MORNING HOURS ON SUN...AS LOW LEVELS
QUICKLY DRY OUT. WINDS BEHIND THE FRONT WILL INCREASE TO 20-30 KTS
WITH SOME LIGHT SNOW DEVELOPING ACROSS PORTIONS OF CENTRAL KANSAS
EARLY SUNDAY. NOT EXPECTING THE LIGHT SNOW TO RESTRICT VSBYS MUCH
WITH VFR CONDITIONS EXPECTED...AS THIS WILL BE MAINLY A LIGHT
SNOW/FLURRY EVENT.
KETCHAM
&&
.PREV DISCUSSION... /ISSUED 926 PM CST SAT DEC 8 2012/
UPDATE...
LOW CLOUDS AND DRIZZLE HAVE OVERSPREAD MUCH OF CENTRAL AND SOUTH
CENTRAL KS THIS EVENING...AS ISENTROPIC LIFT CONTINUES IN THE
295-300K LAYER. THIS WEAK LIFT HAS LED TO SOME SATURATION IN THE
LOWEST LAYERS OF THE ATMOSPHERE...WITH WIDESPREAD STRATUS BUILDING
DOWN AS THE EVENING PROGRESSES WITH DRIZZLE AND SOME AREAS OF FOG.
THIS DRIZZLE AND FOG WILL BE SHORT LIVED...ESPECIALLY ACROSS CENTRAL
KS...AS A STRONG COLD FRONT PUSHES INTO CENTRAL KS BY AROUND 06Z/SUN
AND KEEPS PUSHING SOUTH ACROSS THE REST OF THE REGION LATE TONIGHT
OR EARLY ON SUN. THIS FRONT WILL SHIFT THE WINDS RAPIDLY AROUND TO
THE NORTH AND BECOME GUSTY AT 20 TO 30 MPH. IT WILL ALSO HELP SCOUR
OUT MOST OF THE LOW LEVEL MOISTURE IS IT PUSHES SOUTH...ENDING THE
DRIZZLE AND FOG AS IT MOVES SOUTH.
AS THIS FRONT APPROACHES...WITH A SHORTWAVE PUSHING ACROSS NEB. LIFT
ASSOCIATED WITH THIS FRONT AND SHORTWAVE COULD LEAD TO SOME LIGHT
RAIN ACROSS CEN KS. COULD SEE THIS LIGHT RAIN CHANCE POSSIBLY TURN
OVER OR MIX WITH SOME LIGHT SNOW...AS COLDER AIR ALOFT MOVES ACROSS
NEB BY EARLY ON SUN. BUT LACK OF DEEP MOISTURE WILL MAINLY LEAD TO
VERY LIGHT PRECIPITATION...WITH MAINLY FLURRIES AS IT TURNS OVER TO
SNOW.
KETCHAM
PREV DISCUSSION... /ISSUED 556 PM CST SAT DEC 8 2012/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
LOW LEVEL ISENTROPIC LIFT FROM THE SOUTH-SOUTHWEST WILL LEAD TO
DETERIORATING FLIGHT CONDITIONS THIS EVENING...AS WIDESPREAD MVFR
CIGS/VSBYS AND AREAS OF IFR CIGS PUSH INTO THE AREA THROUGH THE
EVENING HOURS. BOTH THE NAM/WRF AND GFS NOT HANDLING THIS LOWER
CEILING TREND VERY WELL...WITH THE LATEST RUC40 CLOSER TO REALITY.
EVEN WENT MORE PESSIMISTIC THAN THE RUC ON CEILINGS AND FOG.
A COLD FRONTAL BOUNDARY LOOKS TO ARRIVE AFTER 06Z/SUN ACROSS CENTRAL
KANSAS...AND FURTHER SOUTH ACROSS SOUTH CENTRAL KS AFTER
09-10Z/SUN. THIS WILL LEAD TO CEILINGS BEGINNING TO LIFT WITH
MVFR/VFR CEILINGS FOR THE MORNING HOURS ON SUN. WINDS BEHIND THE
FRONT WILL INCREASE TO 20-30 KTS WITH SOME LIGHT SNOW DEVELOPING
ACROSS PORTIONS OF CENTRAL KANSAS ON SUNDAY. NOT EXPECTING THE LIGHT
SNOW TO RESTRICT VSBYS MUCH...AS THIS WILL BE MAINLY A LIGHT SNOW
EVENT/FLURRY EVENT.
KETCHAM
PREV DISCUSSION... /ISSUED 311 PM CST SAT DEC 8 2012/
DISCUSSION...
MAIN FORECAST CONCERNS ARE PRECIP CHANCES AND TYPE TONIGHT THROUGH
SUN ALONG WITH HOW COLD TO GO FOR SUN-MON.
SYNOPSIS:
STRONG SHORTWAVE IS DIVING OVER THE NORTHERN ROCKIES AND APPROACHING
THE NORTHERN HIGH PLAINS. AT THE SURFACE...TROUGHING EXTENDS FROM SW
SD INTO EASTERN CO. THIS HAS LEFT WARM MOIST FLOW OVER THE SOUTHERN
AND CENTRAL PLAINS WHICH HAS ALLOWED LOW CLOUDS TO MOVE BACK IN
ACROSS MUCH OF THE FORECAST AREA.
TONIGHT-SUN NIGHT:
WITH THE LOW LEVEL WARM MOIST FLOW REMAINING IN PLACE...THINKING
THAT THE LOW CLOUDS WILL MAINTAIN AND WILL LIKELY LOWER A BIT THIS EVENING.
IN ADDITION ALSO FEEL THAT AFTER DARK SOME LIGHT FOG AND DRIZZLE
WILL ACCOMPANY THE LOW CIGS. MID LEVEL LIFT WILL COMMENCE OVER
CENTRAL AND NORTHEAST KS THIS EVENING WHICH SHOULD RESULT IN SOME
LIGHT SHOWERS WITH SOME OF THESE SHOWERS TRANSITIONING TO SOME LIGHT
SNOW AFTER AFTER 3 AM AS MUCH COLDER AIR STARTS TO SPILL-IN FROM THE
NORTH. NOT EXPECTING ANYTHING IN THE WAY OF ACCUMULATION OVERNIGHT.
JUST LIKE THE LAST FEW MODEL RUNS...THE MAIN PIECE OF ENERGY IS
EXPECTED TO BREAK OFF INTO TWO PIECES. ONE WILL MOVE TOWARDS THE
GREAT LAKES WHILE THE OTHER DIVES OVER THE DESERT SW AND EVENTUALLY
THE SOUTHERN PLAINS. STILL THINKING THAT THE PRECIP ON SUN WILL
PRIMARILY BE IN THE FORM OR FLURRIES AND SPRINKLES. THE EXCEPTION
WOULD BE THE EAST AND NORTHEAST FRINGES OF THE FORECAST AREA WHERE
THE DEEPER LIFT AND MOISTURE WILL BE SITUATED. EVEN THE LOCATIONS
THAT DO SEEM SOME SNOW SHOWERS CAN EXPECT TO ONLY PICKUP VERY LIGHT
AMOUNTS. THE MAIN STORY WITH THIS SYSTEM WILL CONTINUE TO BE THE
COLDEST TEMPS OF THE SEASON SO FAR WITH SINGLE DIGITS A GOOD BET FOR
MUCH OF CENTRAL KS MON MORNING.
MON-SAT:
THE LONGWAVE TROUGH IS EXPECTED TO POSITION ITSELF OVER THE CENTRAL
CONUS TO START THE WORK WEEK AS ADDITIONAL UPPER IMPULSES DIVE DOWN
THE BACKSIDE OF THE TROUGH AND ACROSS THE SOUTHERN PLAINS FOR MON
NIGHT INTO TUE. THIS PATTERN WILL RESULT IN A CONTINUATION OF BELOW
NORMAL TEMPS WITH THE MOISTURE AND ASSOCIATED PRECIP CHANCES PUSHED
WELL EAST OF THE FORECAST AREA. BY MID WEEK THE UPPER PATTERN WILL
QUICKLY TRANSITION FROM NW FLOW ALOFT TO SW FLOW BY WED AFTERNOON AS
OUR NEXT SHORTWAVE DIGS OVER THE WEST COAST. THIS WILL GET THE
PLAINS BACK INTO A WARMING PATTERN THAT WILL CONTINUE FOR THU INTO
FRI.
THE SHORTWAVE WILL START TO DIRECTLY IMPACT THE AREA BY FRI INTO
SAT. THE ECMWF IS MUCH MORE COMPACT THE MORE PROGRESSIVE WITH THIS
WAVE COMPARED TO THE GFS. REGARDLESS OF WHICH ONE VERIFIES IT
APPEARS THE BEST SNOW CHANCES WILL BE NORTH OF THE FORECAST AREA
WITH SOME SHOWERS AND EVEN A FEW STORMS POSSIBLE FOR
FRI...TRANSITIONING TO SOME LIGHT SNOW OR FLURRIES FOR FRI NIGHT.
LAWSON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 35 38 13 35 / 10 10 10 0
HUTCHINSON 34 35 12 36 / 10 10 10 0
NEWTON 34 37 12 35 / 10 20 10 0
ELDORADO 36 39 14 34 / 10 20 10 0
WINFIELD-KWLD 37 39 15 36 / 10 20 10 0
RUSSELL 28 32 6 39 / 20 10 10 0
GREAT BEND 31 33 7 38 / 10 10 10 0
SALINA 31 32 10 37 / 20 10 10 0
MCPHERSON 34 35 11 36 / 20 10 10 0
COFFEYVILLE 44 45 19 36 / 10 30 10 10
CHANUTE 42 43 18 34 / 10 30 10 10
IOLA 41 43 17 33 / 10 30 10 10
PARSONS-KPPF 43 44 18 35 / 10 30 10 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1018 PM MST SAT DEC 8 2012
.UPDATE...
ISSUED AT 757 PM MST SAT DEC 8 2012
PER SATELLITE AND LATEST MODEL DATA INCREASED CLOUD COVER THROUGH
TOMORROW MORNING. LOOKING AT CURRENT SURFACE OBSERVATION DATA AND
CONSIDERING THE HIGHER WINDS/MORE CLOUD COVER...CHOSE TO RAISE
MINS A LITTLE WHICH DOES FIT WITH SOME OF THE NEWER GUIDANCE.
CURRENT PRECIPITATION FORECAST LOOKS FINE. WINDS WILL BEGIN
GUSTING TO JUST UNDER WIND ADVISORY CRITERIA. IT LOOKS CLOSE FOR
WIND ADVISORY AND WILL LET THE OVERNIGHT SHIFT ADDRESS THAT. GRIDS
ARE ALREADY REFLECTING IT.
UPDATE ISSUED AT 605 PM MST SAT DEC 8 2012
JUST COMPLETED AN UPDATE. FIRST FRONT IN A SERIES OF FRONTS
ALREADY BLASTING THROUGH WHICH IS FASTER THAN ANY MODEL DEPICTION
OR WHAT THE GRIDS HAD WHICH IS NOT UNCOMMON IN THIS SCENARIO. NOT
ONLY IS THE FRONT THROUGH...BUT WIND SPEEDS ALREADY TO NEAR 40 MPH
IN SOME LOCATIONS. RUC WAS THE FASTEST MODEL BUT WAS STILL A LITTLE
SLOW AND UNDERDONE ON THE SPEEDS. SO USED IT AND MODIFIED WITH
REALITY. HOPEFULLY NEWER MODEL DATA WILL CATCH UP WITH THIS. ALSO
INCREASED SPEEDS FOR LATER TONIGHT AND TOMORROW AS WELL WITH WHAT
LOOKS TO BE DECENT MIXING. CONSIDERING THE COLD AIR ADVECTION
ALREADY OCCURRING...THERE MAY NOT BE ANY LOW LEVEL INVERSION TO
OVERCOME AND WIND SPEEDS MAY BE EVEN HIGHER THAN WHAT I HAVE
DEPICTED. WILL CONTINUE TO WATCH AND TWEAK AS NEWER DATA COMES IN.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 1059 AM MST SAT DEC 8 2012
EXCEPT FOR THE COLD AIR MOVING IN BEHIND THE FRONT THIS EVENING
AND OVERNIGHT...THIS EVENT IS BEGINNING TO LOOK MORE LIKE A NON-
EVENT. HAVE TONED DOWN THE MENTION OF ANY ACCUMULATING SNOW AND
HAVE PUT IN A MENTION OF SPRINKLES OR FLURRIES IN THE FAR
NORTHWEST CORNER OF THE FORECAST AREA BEFORE 00Z WITH A MORE
EXTENSIVE AREA OF FLURRIES ALONG AND BEHIND THE FRONT AS IT MOVES
THROUGH THE FORECAST AREA TONIGHT. THE NAM CONTINUES TO BE DRY WITH THE
ECMWF AND GFS ONLY PRODUCING AROUND ONE HUNDREDTH OF QPF ALONG THE
NORTHERN AND WESTERN FRINGES OF THE FORECAST AREA. FLURRIES WILL
DIMINISH EARLY SUNDAY WITH SKIES BEGINNING TO CLEAR BY LATE SUNDAY
AFTERNOON AS SURFACE HIGH PRESSURE BEGINS TO MOVE INTO THE REGION.
BECAUSE OF THE DECREASING CLOUDS COVER AND SLACKENING WINDS SUNDAY
NIGHT...EXPECT THE COLDEST TEMPERATURES OF THE SEASON WITH LOWS
DROPPING DOWN TO AROUND ZERO IN SOME LOCATIONS. WIND CHILL BELOW
ZERO WILL BE COMMON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 112 PM MST SAT DEC 8 2012
SUNDAY NIGHT THROUGH TUESDAY NIGHT THE BASE OF THE LONG WAVE TROUGH
WILL REMAIN OVER THE AREA.
SUNDAY NIGHT THE TROUGH AXIS...FROM THE SHORT WAVE TROUGH
RESPONSIBLE FOR THE WINTER STORM OVER THE NORTHERN PLAINS...WILL
MOVE THROUGH THE AREA. UNFORTUNATELY DRIER AIR WILL BE OVER THE
AREA BY THE TIME THE TROUGH AXIS MOVES THROUGH AND THE LEFT
ENTRANCE OF THE 500-300MB JET WILL BE OVER THE AREA AHEAD OF THE
TROUGH AXIS...LEADING TO DRY CONDITIONS FOR THE AREA. WINDS WILL
DECREASE DURING THE EVENING AS A SURFACE HIGH BUILDS INTO THE
AREA. WITH LITTLE TO NO WIND AND CLEAR SKIES...TEMPERATURES WILL
FALL TO THE SINGLE DIGITS. ANY WIND THAT DOES DEVELOP WILL PRODUCE
WIND CHILL VALUES NEAR 15 BELOW ZERO.
MONDAY SEVERAL WEAKER SHORT WAVE TROUGHS MOVE THROUGH...BUT THERE
WILL BE LITTLE TO NO MOISTURE TO WORK WITH. DURING THE LATE
AFTERNOON/EVENING AREA SOUNDINGS SATURATE AS MOISTURE MOVES INTO THE
AREA BEHIND A SURFACE AND UPPER LEVEL TROUGH. HOWEVER THE
INCREASED MOISTURE WILL BE IN THE SUBSIDENCE AREA BEHIND THE SHORT
WAVE TROUGH.
FOR THE TUESDAY THROUGH SATURDAY PERIOD...DRY CONDITIONS WILL
CONTINUE TO PREVAIL. THE LONG WAVE TROUGH MOVES EAST TUESDAY
ALLOWING A LONG WAVE RIDGE TO MOVE OVER THE CENTRAL PLAINS THROUGH
THE MAJORITY OF NEXT WEEK. MEANWHILE THE NEXT SHORT WAVE TROUGH
MOVES ONSHORE WEDNESDAY...APPROACHING THE AREA FRIDAY. MODELS AGREE
WITH THE TRACK OF THE TROUGH...MOVING IT OVER THE TEXAS AND OKLAHOMA
PANHANDLES. THE POSITION OF THE TROUGH IS STILL TOO FAR SOUTH FOR
THE AREA TO RECEIVE ANY PRECIPITATION. HOWEVER THE MODELS HAVE
TRENDED FURTHER NORTH WITH THE TROUGH SINCE YESTERDAY. FRIDAY NIGHT
THE GEFS MEMBERS INDICATED A SLIGHT CHANCE FOR SOME PRECIPITATION
OVER THE EASTERN PART OF THE AREA. GFS ISENTROPIC LIFT DOES SHOW
SOME LIFT AND MOISTURE CO-LOCATED AROUND 600MB OVER THOSE
LOCATIONS. IF THIS FEATURE IS STILL THERE TOMORROW...SLIGHT CHANCES
MAY NEED TO BE ADDED FOR THE EAST FRIDAY NIGHT.
TEMPERATURES WILL BE NEAR NORMAL...WITH A SMALL WARMING TREND
THROUGH THE PERIOD. A COLD FRONT WILL MOVE THROUGH FRIDAY BEHIND
THE UPPER LEVEL TROUGH...BUT THE COOLER AIR MASS BEHIND THE FRONT
WILL QUICKLY MOVE EAST FOLLOWING THE UPPER LEVEL TROUGH. THIS WILL
ALLOW TEMPERATURES FOR SATURDAY TO REMAIN LARGELY UNAFFECTED BY THE
FRONTAL PASSAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1016 PM MST SAT DEC 8 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. SOME LOW CLOUDS
COULD OCCUR BUT ARE EXPECTED TO SCATTERED AND NEAR TO SLIGHTLY
ABOVE MVFR. STRONG AND GUSTY NORTH TO NORTHWEST WILL CONTINUE NEAR
SUNSET.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...LOCKHART
LONG TERM...JTL
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
456 AM EST SUN DEC 9 2012
.SYNOPSIS...
LOW PRESSURE COMING NORTHEAST FROM MISSOURI WILL BRING THE UPPER OHIO
VALLEY...MILD TEMPERATURES AND BOUTS OF RAIN INTO MONDAY...
FOLLOWED BY A COOL DOWN TO SEASONABLE TEMPERATURES TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BASED OF BLEND OF RECENT SREF MODEL OUTPUT...WITH DETAILS FROM
RECENT RAP WRF-NMM AND NAM MODEL RUNS...SHOW A LOW PRESSURE
SYSTEM WILL BE MOVING FROM MISSOURI THIS MORNING TO OHIO THIS
EVENING. WARM FRONT CONVERGENCE ENHANCED BY JETSTREAM DYNAMICS
ALOFT WILL SPAWN A SURGE OF RAIN TO SPREAD NORTHWARD ACROSS THE UPPER
OHIO TODAY. LOCATIONS SOUTH OF THE I-70 CORRIDOR CAN EXPECT BOUTS
OF RAIN STARTING THIS MORNING...WHILE LOCATIONS FARTHER NORTH MAY
NOT GET MUCH RAIN UNTIL AFTERNOON.
HAVE ADDED MENTION OF DENSE FOG ACROSS THE HIGHER ELEVATIONS OF
TUCKER WV COUNTY AND GARRETT CO MD COUNTY...BASED ON RECENT
SURFACE DATA. FOG SHOULD CONTINUE INTO MID MORNING WHEN FIRST BOUT
OF RAIN LESSENS.
TEMPERATURES WILL CONTINUE TO BE MILD WITH HIGHS THIS AFTERNOON
ABOUT 15 DEGREES WARMER THAN NORMAL...PER BLEND OF GFS AND NAM
MOS AND RAP AND GFS LAMP HOURLY VALUES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
RECENT SREF MODEL OUTPUT SHOWS A NORTHEAST SURGE OF MODERATE RAIN
ACROSS THE UPPER OHIO TONIGHT AND MONDAY...UNTIL THE LOW PRESSURE
CENTER PASSES NORTHEAST TO NEW YORK STATE MONDAY AFTERNOON. CONCUR
WITH HPC THAT RAIN AMOUNTS FOR THIS EVENT CAN BE ON THE ORDER OF
1.0 TO 1.3 INCHES.
TEMPERATURES WILL REMAIN MILD WITH VALUES MAINLY IN THE UPPER 40S
TO MID 50S INTO MIDDAY MONDAY. ONCE THE LOW PRESSURE CENTER EXITS
NORTHEAST...A COLD FRONTAL PASSAGE WILL ENSUE MONDAY
AFTERNOON. THE COOL DOWN CAN BEGIN MONDAY AFTERNOON WITH VALUES
LATE MONDAY NIGHT INTO WEDNESDAY NEAR OR SLIGHTLY COLDER THAN
NORMAL.
CONSEQUENTLY REMAINING POSTFRONTAL SHOWERS MONDAY NIGHT CAN TURN
TO SNOW SHOWERS LATE. THE POSTFRONTAL COLD POOL CAN REMAIN ACROSS
THE UPPER OHIO VALLEY INTO WEDNESDAY...KEEPING SKIES MAINLY
CLOUDY. HOWEVER CONDITIONS TUESDAY INTO WEDNESDAY SHOULD BE DRY AS
INCOMING HIGH PRESSURE SUBSIDENCE AND LOW LEVEL WESTERLY WINDS
WILL MITIGATE CHANCES OF LAKE EFFECT SNOW SHOWER DEVELOPMENT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS ECMWF AND CANADIAN MODEL OUTPUT CONCUR THAT NEARBY HIGH
PRESSURE WILL PROMOTE DRY CONDITIONS WEDNESDAY NIGHT INTO FRIDAY.
ECMWF AND GFS AGREE THAT A CLOSED MID-LEVEL LOW WILL DEVELOP
ACROSS THE CENTRAL PLAINS ON FRIDAY NIGHT AND SHIFT INTO THE GREAT
LAKES REGION BY SATURDAY. AHEAD OF THIS FEATURE...CHANCE POPS
RETURN TO THE AREA. MODEL PREDICTABILITY A WEEK OUT MAKES IT
DIFFICULT TO PIN DOWN SPECIFICS IN FRONTAL PLACEMENT...HOWEVER
THIS PATTERN FAVORS THE POTENTIAL FOR OVERRUNNING ALONG WITH WARM
FRONTAL RAIN SHOWERS WELL AHEAD OF THE LOW.
TEMPERATURES WILL REBOUND TO WARMER THAN NORMAL THIS PERIOD WITH
VALUES FRIDAY AND SATURDAY ANYWHERE FROM 5 TO 10 DEGREES ABOVE
NORMAL.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
CONDITIONS SHOULD REMAIN MVFR THROUGH MUCH OF THE DAY. ALTHOUGH CURRENT
TAFS DEPICT RAIN BEGINNING TO AFFECT TERMINALS BY NOON...INCOMING
MODEL RUNS SUGGEST THAT IT MAY TAKE LONGER FOR SHOWERS ASSOCIATED
WITH A WARM FRONT TO MOVE INTO THE AREA. CEILINGS WILL LOWER TO
IFR AFTER A FEW HOURS OF RAIN.
WINDS WILL SHIFT FROM NORTHEAST TO THE SOUTHEAST DURING THE
DAY...WHICH COULD ALLOW FOR A BRIEF INCREASE OF WINDS AT KLBE DUE
TO DOWNSLOPING. WINDS WILL BECOME SOUTHERLY ONCE THE WARM FRONT
MOVES THROUGH THIS EVENING.
.OUTLOOK.../MONDAY THROUGH THURSDAY/...
MVFR AND PSBL IFR RESTRICTIONS WL CONTINUE WITH RAIN MONDAY AS A
COLD FRONT MOVES THROUGH. MVFR CONDITIONS ARE EXPECTED MONDAY NIGHT
INTO TUESDAY. LINGERING RAIN SHOWERS MAY CHANGE TO SCATTERED SNOW
SHOWERS BEFORE ENDING EARLY TUESDAY. HIGH PRES AND VFR CONDS ARE
EXPECTED LATER TUESDAY THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
420 AM EST SUN DEC 9 2012
.SYNOPSIS...
LOW PRESSURE COMING NORTHEAST FROM MISSOURI WILL BRING THE UPPER OHIO
VALLEY...MILD TEMPERATURES AND BOUTS OF RAIN INTO MONDAY...
FOLLOWED BY A COOL DOWN TO SEASONABLE TEMPERATURES TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BASED OF BLEND OF RECENT SREF MODEL OUTPUT...WITH DETAILS FROM
RECENT RAP WRF-NMM AND NAM MODEL RUNS...SHOW A LOW PRESSURE
SYSTEM WILL BE MOVING FROM MISSOURI THIS MORNING TO OHIO THIS
EVENING. WARM FRONT CONVERGENCE ENHANCED BY JETSTREAM DYNAMICS
ALOFT WILL SPAWN A SURGE OF RAIN TO SPREAD NORTHWARD ACROSS THE UPPER
OHIO TODAY. LOCATIONS SOUTH OF THE I-70 CORRIDOR CAN EXPECT BOUTS
OF RAIN STARTING THIS MORNING...WHILE LOCATIONS FARTHER NORTH MAY
NOT GET MUCH RAIN UNTIL AFTERNOON.
TEMPERATURES WILL CONTINUE TO BE MILD WITH HIGHS THIS AFTERNOON
ABOUT 15 DEGREES WARMER THAN NORMAL...PER BLEND OF GFS AND NAM
MOS AND RAP AND GFS LAMP HOURLY VALUES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
RECENT SREF MODEL OUTPUT SHOWS A NORTHEAST SURGE OF MODERATE RAIN
ACROSS THE UPPER OHIO TONIGHT AND MONDAY...UNTIL THE LOW PRESSURE
CENTER PASSES NORTHEAST TO NEW YORK STATE MONDAY AFTERNOON. CONCUR
WITH HPC THAT RAIN AMOUNTS FOR THIS EVENT CAN BE ON THE ORDER OF
1.0 TO 1.3 INCHES.
TEMPERATURES WILL REMAIN MILD WITH VALUES MAINLY IN THE UPPER 40S
TO MID 50S INTO MIDDAY MONDAY. ONCE THE LOW PRESSURE CENTER EXITS
NORTHEAST...A COLD FRONTAL PASSAGE WILL ENSUE MONDAY
AFTERNOON. THE COOL DOWN CAN BEGIN MONDAY AFTERNOON WITH VALUES
LATE MONDAY NIGHT INTO WEDNESDAY NEAR OR SLIGHTLY COLDER THAN
NORMAL.
CONSEQUENTLY REMAINING POSTFRONTAL SHOWERS MONDAY NIGHT CAN TURN
TO SNOW SHOWERS LATE. THE POSTFRONTAL COLD POOL CAN REMAIN ACROSS
THE UPPER OHIO VALLEY INTO WEDNESDAY...KEEPING SKIES MAINLY
CLOUDY. HOWEVER CONDITIONS TUESDAY INTO WEDNESDAY SHOULD BE DRY AS
INCOMING HIGH PRESSURE SUBSIDENCE AND LOW LEVEL WESTERLY WINDS
WILL MITIGATE CHANCES OF LAKE EFFECT SNOW SHOWER DEVELOPMENT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS ECMWF AND CANADIAN MODEL OUTPUT CONCUR THAT NEARBY HIGH
PRESSURE WILL PROMOTE DRY CONDITIONS WEDNESDAY NIGHT INTO FRIDAY.
ECMWF AND GFS AGREE THAT A CLOSED MID-LEVEL LOW WILL DEVELOP
ACROSS THE CENTRAL PLAINS ON FRIDAY NIGHT AND SHIFT INTO THE GREAT
LAKES REGION BY SATURDAY. AHEAD OF THIS FEATURE...CHANCE POPS
RETURN TO THE AREA. MODEL PREDICTABILITY A WEEK OUT MAKES IT
DIFFICULT TO PIN DOWN SPECIFICS IN FRONTAL PLACEMENT...HOWEVER
THIS PATTERN FAVORS THE POTENTIAL FOR OVERRUNNING ALONG WITH WARM
FRONTAL RAIN SHOWERS WELL AHEAD OF THE LOW.
TEMPERATURES WILL REBOUND TO WARMER THAN NORMAL THIS PERIOD WITH
VALUES FRIDAY AND SATURDAY ANYWHERE FROM 5 TO 10 DEGREES ABOVE
NORMAL.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
CONDITIONS SHOULD REMAIN MVFR THROUGH MUCH OF THE DAY. ALTHOUGH CURRENT
TAFS DEPICT RAIN BEGINNING TO AFFECT TERMINALS BY NOON...INCOMING
MODEL RUNS SUGGEST THAT IT MAY TAKE LONGER FOR SHOWERS ASSOCIATED
WITH A WARM FRONT TO MOVE INTO THE AREA. CEILINGS WILL LOWER TO
IFR AFTER A FEW HOURS OF RAIN.
WINDS WILL SHIFT FROM NORTHEAST TO THE SOUTHEAST DURING THE
DAY...WHICH COULD ALLOW FOR A BRIEF INCREASE OF WINDS AT KLBE DUE
TO DOWNSLOPING. WINDS WILL BECOME SOUTHERLY ONCE THE WARM FRONT
MOVES THROUGH THIS EVENING.
.OUTLOOK.../MONDAY THROUGH THURSDAY/...
MVFR AND PSBL IFR RESTRICTIONS WL CONTINUE WITH RAIN MONDAY AS A
COLD FRONT MOVES THROUGH. MVFR CONDITIONS ARE EXPECTED MONDAY NIGHT
INTO TUESDAY. LINGERING RAIN SHOWERS MAY CHANGE TO SCATTERED SNOW
SHOWERS BEFORE ENDING EARLY TUESDAY. HIGH PRES AND VFR CONDS ARE
EXPECTED LATER TUESDAY THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
117 AM EST SUN DEC 9 2012
.SYNOPSIS...
A NORTHEASTBOUND LOW PRESSURE SYSTEM FROM ARKANSAS WILL BRING MILD
TEMPERATURES AND BOUTS OF RAIN TO THE UPPER OHIO VALLEY INTO
MONDAY...THEN A COOL DOWN TO SEASONABLE TEMPERATURES TUESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
HAVE FORECASTED A SLIGHTLY SLOWER NORTHWARD SPREAD OF RAIN ACROSS
THE UPPER OHIO VALLEY TODAY...BASED ON BLEND OF RECENT SREF MODEL
OUTPUT WITH DETAILS FROM RECENT RAP WRF-NMM AND NAM MODEL RUNS.
TEMPERATURES WILL CONTINUE MILD WITH NEAR STEADY TEMPERATURES
OVERNIGHT AND HIGHS SUNDAY AFTERNOON ABOUT 15 DEGREES WARMER THAN
NORMAL.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
EXPECT WIDESPREAD RAIN TO CONTINUE SUNDAY NIGHT INTO MONDAY AS
FRONT GRADUALLY CROSSES REGION AS MAIN SURFACE LOW MOVES TO NEW
ENGLAND AND UPPER TROUGH SLOWLY SHIFTS EAST.
RAIN WILL BEGIN TO SHIFT SOUTHEAST WITH FRONT LATE DAY MONDAY AND
AS COLDER AIR WORKS IN SOME CHANGE OVER TO SNOW SHOWERS WILL OCCUR
MONDAY NIGHT.
TOTAL RAINFALL FOR THE EVENT WILL BE AROUND AN INCH
BUT WILL BE SPREAD OVER A 24 TO 36 HOUR PERIOD SO NO FLOOD
PROBLEMS EXPECTED.
SCATTERED SNOW SHOWERS MONDAY NIGHT INTO TUESDAY WILL NOT AMOUNT
TO MUCH AS DEEP MOISTURE WILL HAVE BEEN SHUNTED WELL EAST. FLOW
OFF THE LAKES WILL BE WEAK MONDAY NIGHT AND TUESDAY DESPITE 85OMB
TEMPS REACHING -9C ACROSS THE LAKES BY 12Z TUESDAY.
QUITE MILD SUNDAY NIGHT AHEAD OF THE FRONT THEN A GRADUAL FALL
WITH FROPA MONDAY. BACK TO NEAR NORMAL FOR MONDAY NIGHT AND TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
GFS/ECMWF/CANADIAN ARE IN AGREEMENT THAT A SURFACE HIGH WILL BUILD
IN FROM THE SOUTHWEST TUESDAY NIGHT INTO WEDNESDAY AND BECOME
CENTERED OVER THE UPPER OHIO VALLEY BY AROUND 00Z THURSDAY. THERE
ARE SOME MODEL INCONSISTENCIES IN THE PASSAGE OF AN UPPER
TROUGH...HOWEVER SUBSIDENCE AND DRY AIR IN THE LOWER LEVEL WILL KEEP
THE FORECAST DRY REGARDLESS OF ITS TIMING. THUS...A DRY FORECAST IS
IN PLACE THROUGH FRIDAY.
ECMWF/GFS AGREE THAT A CLOSED MID-LEVEL LOW WILL DEVELOP ACROSS THE
CENTRAL PLAINS ON FRIDAY NIGHT AND SHIFT INTO THE GREAT LAKES REGION
BY SATURDAY. AHEAD OF THIS FEATURE...CHANCE POPS RETURN TO THE AREA.
MODEL PREDICTABILITY A WEEK OUT MAKES IT DIFFICULT TO PIN DOWN
SPECIFICS IN FRONTAL PLACEMENT...HOWEVER THIS PATTERN FAVORS THE
POTENTIAL FOR OVERRUNNING ALONG WITH WARM FRONTAL RAIN SHOWERS WELL
AHEAD OF THE LOW.
TEMPERATURES WILL BE NEAR SEASONAL NORMALS ON WEDNESDAY WITH THE
POST-FRONTAL CANADIAN AIR MASS STILL IN PLACE BEHIND THE FRONT AND
SOME INCREASED CLOUDINESS FROM THE PASSING MID-LEVEL TROUGH. THE
MID-LEVEL FLOW WILL BECOME MORE SOUTHWESTERLY THURSDAY THROUGH
SATURDAY...ALLOWING FOR TEMPS TO BE AROUND 5 TO 10 DEGREES ABOVE
NORMAL.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
SFC ANALYSIS SHOWING A COLD FRONT FROM SW PA INTO NRN WV. THE
FRONT WL CONTINUE TO DRIFT SWD TONIGHT. EXPECTING MVFR NR THE
FRONT...WITH A BRIEF PD OF VFR BEHIND THE FRONT. MVFR...AND EVEN
SOME IFR AT THE NRN TAF SITES...WL THEN RETURN AND PERSIST MUCH OF
THE NIGHT.
THE FRONT STARTS TO RETURN N AS A WARM FRONT ERLY SUN
MRNG. THIS WL SPREAD RAIN INTO THE SRN TAF SITES. MOST OF THE RAIN
ELSEWHERE SHOULD MOVE IN DURING THE MID-LATE AFTN SUN WITH LOW
END MVFR. EXPECTING GRADUALLY VEERING WINDS THROUGH THE PD.
.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
MVFR AND PSBL IFR RESTRICTIONS WL CONTINUE WITH RAIN SUNDAY NIGHT
INTO MONDAY AS A COLD FRONT MOVES THROUGH. MVFR CONDS AND A FEW
SNOW SHOWERS ARE PSBL MONDAY NIGHT INTO ERLY TUE. HIGH PRES AND
VFR CONDS ARE EXPECTED LATER TUE THROUGH THU.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1240 AM EST SUN DEC 9 2012
.UPDATE...
ISSUED AT 739 PM EST SAT DEC 8 2012
WITH MOCLR SKIES OVER THE W HALF OF UPR MI UNDER SFC RDG AXIS/PWAT
0.18 INCH AS OBSVD ON THE 00Z GRB RAOB...SFC TEMPS HAVE ALREADY
REACHED FCST MINS EARLY THIS EVNG. SO TENDED TO LOWER THESE NUMBERS
A COUPLE OF DEGREES OVER THE W HALF BEFORE INCRSG HI CLDS FM THE SW
ARRIVE BY MIDNGT AND AT LEAST STEADY OFF THE TEMP DROP.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 340 PM EST SAT DEC 8 2012
HIGH PRESSURE IS CURRENTLY LOCATED IN MANITOBA AND ONTARIO...WITH A
RIDGE STRETCHING SOUTHEAST INTO WESTERN UPPER MI AND WI. LIGHT
NORTHWEST FLOW...WITH RUC ANALYZED H850 OF -10 TO -12C...HAS LED TO
LAKE EFFECT CLOUDS AND LIGHT SNOW SHOWERS THROUGH THIS AFTERNOON IN
THE TRADITIONAL NORTHWEST FLOW LOCATIONS.
UPSTREAM...PV ANOMALY IN SRN SD AND NW NEBRASKA WILL SHIFT ENE
TONIGHT AND INTO MN BY 12Z SUNDAY...WITH THE SURFACE LOW FOLLOWING
SUIT. THIS ANOMALY WILL SHIFT NORTHEAST THROUGH WESTERN UPPER
MICHIGAN THROUGH THE DAY ON SUNDAY AND BE WEAKENING DUE TO INFLUENCE
OF SECOND ANOMALY ENTERING NORTHERN MN AND THE SOUTHERN WAVE
BECOMING MORE DOMINATE AS IT DIVES SOUTHEAST THROUGH THE CENTRAL
ROCKIES DURING THE DAY ON SUNDAY. THIS...COMBINED WITH A
STRENGTHENING JET OVER THE OHIO VALLEY ON SUNDAY...WILL ALLOW A
SECONDARY LOW TO DEVELOP IN THE OHIO VALLEY REGION DURING THE DAY
AND PRODUCE A BROAD AREA OF LOW PRESSURE WHICH TRANSITIONS THE LOW
OVER OUR AREA TO A TROUGH. STILL DIFFERENCES IN THE MODELS...BOTH
RUN-TO-RUN AND BETWEEN MODELS...WITH THE POTENTIAL WEAKENING/SPEED
OF THE PV ANOMALY AND THE LOCATION OF THE ASSOCIATED SURFACE TROUGH
HEADING INTO SUNDAY AFTERNOON/EVENING. LATEST TRENDS IN THE MODELS
ARE FOR A SLOWER MOVEMENT OF THE PV ANOMALY THROUGH UPPER MICHIGAN
ON SUNDAY...WHICH KEEPS THE SURFACE TROUGH AXIS OVER
NORTHERN/CENTRAL WISCONSIN.
TONIGHT...THE HIGH PRESSURE RIDGE EXITING TO THE NORTHEAST WILL
PRODUCE QUIET WEATHER BEFORE THE SYSTEM. UPSTREAM DRYING THIS
AFTERNOON HAS ATE AWAY AT SOME OF THE LAKE EFFECT CLOUDS OVER THE
WEST AND ONCE DAYTIME HEATING IS LOST...EXPECT THE SAME TO OCCUR
OVER THE INTERIOR LOCATIONS THIS EVENING. THIS CLEARING WILL MAKE
FOR TRICKY LOW TEMPERATURES TONIGHT AND FOLLOWED THE PREVIOUS SHIFT
BY TRENDED THEM DOWN A LITTLE MORE AS PWATS 65 PERCENT OF NORMAL
AND THERE ARE LIGHT WINDS. WENT WITH LOWS IN UPPER TEENS...BUT BASED
OFF HOW QUICKLY TEMPS FELL THIS MORNING IN CLEARING AREAS...THAT MAY
NOT BE COLD ENOUGH. OTHERWISE...MID/HIGH LEVEL CLOUDS WILL BE ON THE
INCREASE FROM THE SOUTHWEST WITH THE APPROACHING SYSTEM.
SUNDAY...PRECIPITATION BUILDS IN FROM SOUTHWEST TO NORTHEAST THROUGH
THE DAY. STARTING BETWEEN 12-15Z NEAR KIWD...LATE MORNING OR EARLY
AFTERNOON OVER THE CENTRAL...AND MID/LATE AFTERNOON OVER THE EAST.
WITH THE LATEST SLOWER TRENDS...HAVE DELAYED THE START A COUPLE OF
HOURS FROM THE PREVIOUS SHIFT. PLENTY OF COLD AIR ALOFT...SO EXPECT
PRECIPITATION TO BE AS ALL SNOW. AS FOR FORCING...BEST MID LEVEL WAA
IS FOCUSED OVER THE SOUTH CENTRAL AND NEAR LAKE MICHIGAN THROUGH
THE DAY. THIS LINES UP WITH WEAK FGEN BETWEEN H850-650 OVER THE AREA
FOR THE AFTERNOON...BUT SEEMS TO FOCUS OVER THE SOUTHEAST HALF OF
THE CWA LATE IN THE AFTERNOON. IN ADDITION...BROAD 280-290K
ISENTROPIC ASCENT WILL SPREAD OVER THE CWA DURING THE DAY.
FINALLY...H850 TEMPS AROUND -9C SHOULD FAVOR SOME LAKE ENHANCEMENT
FOR THE KEWEENAW AND ALSO FOR LOCATIONS NEAR LAKE MICHIGAN FAVORED
BY ESE WINDS.
WITH THE SLIGHT DELAY WITH THE SLOWER ARRIVAL OF THE PV ANOMALY AND
SURFACE TROUGH BEING A LITTLE FARTHER SOUTH...BEST PRECIPITATION
STRADDLES THE SHORT/LONG TERM TRANSITION. ALL IN ALL...MODEL QPF
FOR SUNDAY INTO SUNDAY NIGHT WITH THE SYNOPTIC FEATURES IS IN THE
0.25-0.4IN FOR MOST AREAS AND WHEN COMBINED WITH A SNOW RATIO AROUND
13-15 TO 1...WOULD PUT 3 TO 6 INCHES OF SYNOPTIC SNOW OVER THE
AREA THROUGH SUNDAY EVENING. OUTSIDE OF ANY LAKE ENHANCEMENT...THE
HIGHEST AMOUNTS SHOULD LINE UP ALONG THE WISCONSIN BORDER WITH THE
SLIGHT SOUTH SHIFT OF THE SURFACE TROUGH. THE LONG TERM DISCUSSION
WILL COVER THE BULK OF THE HEADLINES...BUT DID DROP THE WATCH OVER
THE WESTERN COUNTIES AND HAVE STARTED A LONGER PERIOD ADVISORY FROM
WEST TO EAST THROUGH THE DAY ON SUNDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 PM EST SAT DEC 8 2012
MAIN CONCERN IS WITH SNOWFALL FORECAST FOR THE FIRST 24 HOURS OF THE
LONG TERM.
SUN NIGHT/MON...IN GENERAL...MODELS ARE IN GOOD AGREEMENT...BUT
THERE ARE SUBTLE VARIATIONS AT SMALLER SCALES THAT BECOME MAGNIFIED
IN THE SNOWFALL FORECAST. THE DIFFICULTY AND UNCERTAINTY IS DUE TO
THE FACT THAT THE SYSTEM OVER THE REGION SUN NIGHT WILL BE MERGING
WITH A SRN STREAM SYSTEM OVER THE OHIO VALLEY...PLUS THE FACT THAT
MODELS HAVE A HARD TIME CONSISTENTLY HANDLING THE PV ANOMALIES THAT
WILL DRIVE A GOOD PORTS OF THE SNOWFALL WITH THIS SYSTEM. LATEST
RUNS OF THE GFS/NAM/REGIONAL GEM/REGIONAL WRF ARE NOW IN BETTER
AGREEMENT IN BRINGING THE WEAKENING PRIMARY PV ANOMALY FROM NW WI AT
00Z MON TO CENTRAL UPPER MI AROUND 06Z MON...THEN SHEARING IT OUT
AND PUSHING IT NORTHEAST BY 12Z MON. MEANWHILE...THE SECONDARY PV
ANOMALY WILL ROTATE INTO CENTRAL/SRN WI...FARTHER S THAN PREVIOUS
RUNS OF THE MODELS. THE TIMING/LOCATION OF THE PV ANOMALIES IS
CONSISTENT WITH THE OVERALL TREND OVER THE LAST FEW RUNS OF THE
MODELS IN SLOWING THE SYSTEM DOWN AND MOVING IT FARTHER S. THE
RESULTING SFC TROUGH LOOKS TO STAY TO THE S OF THE CWA OVER
CENTRAL/NRN WI. LOW LEVEL FLOW WILL GENERALLY BE ELY AT 00Z MON WITH
850MB TEMPS AROUND -9C. BY 06Z MON...LOW LEVEL WINDS BACK TO MORE
ENE...THEN TO NNE BY 12Z MON AS 850MB TEMPS FALL TO -11C. SYNOPTIC
SNOWFALL AMOUNTS WILL BE HIGHEST OVER THE SRN HALF OF UPPER MI SUN
NIGHT...BUT THAT SHOULD BE OFFSET SOME BY UPSLOPE FLOW IN SOME NRN
LOCATIONS...PARTICULARLY NCENTRAL UPPER MI AND THE KEWEENAW...THEN
OVER THE WRN U.P. LATER SUN NIGHT. 850MB TEMPS FALL ANOTHER COUPLE
OF DEGREES THROUGH THE DAY MON WHILE FLOW BECOMES INCREASING
ANTICYCLONIC AS THE SFC TROUGH MOVES QUICKLY E AND A RIDGE MOVES
OVER WRN LAKE SUPERIOR BY 00Z TUE. THUS...EXPECT LES FROM NNW WINDS
MON MORNING...DIMINISHING THROUGH MON EVENING. WITH THIS TYPE OF
SYSTEM THERE IS INHERENT UNCERTAINTY THAT WILL PROBABLY NOT BE
RESOLVED UNTIL THE SYSTEM IS ON THE DOORSTEP OF THE CWA...SO
CONFIDENCE IN SNOWFALL AMOUNTS IS STILL SOMEWHAT LIMITED. STORM
TOTAL SNOWFALL AMOUNTS OF 3 TO 6 INCHES IS EXPECTED...WITH SOME
LOCALLY HIGHER AMOUNTS POSSIBLE IN THE HIGHER TERRAIN OF WRN
GOGEBIC/ONTONAGON COUNTIES AND NW MARQUETTE/NE BARAGA COUNTIES.
DECIDED IN COORDINATION WITH SHORT TERM SHIFT TO ISSUE WINTER WX
ADVISORIES OVER THE ENTIRE CWA. COULD SEE SOME LOCATIONS GO SLIGHTLY
ABOVE ADVISORY CRITERIA...BUT NOT CONFIDENT ENOUGH IN THAT TO
JUSTIFY WARNING. ALSO...THE TIME THAT THE HEAVIEST SNOW WILL FALL
/SUN EVENING AND EARLY SUN NIGHT/ IS NOT A HIGH IMPACT TIME TRAVEL
WISE...PLUS THE FACT THAT THE STORM TOTAL WILL OCCUR OVER 24 HOURS
OR MORE. ALSO DECIDED ON THE ADVISORY WITH THE IDEA THAT IT WOULD BE
EASIER TO UPGRADE TO A WARNING IF NEEDED THAN HAVE TO CANCEL
WARNINGS AND ISSUE AN ADVISORY IF THE BORDERLINE WARNING AMOUNTS DO
NOT OCCUR...WHICH WOULD LEAD TO A MISSED EVENT FOR
VERIFICATION...SORT OF THE PATH OF LEAST REGRET.
A VERY WEAK SHORTWAVE TROUGH MOVES ACROSS THE AREA TUE INTO TUE
NIGHT...BRINGING SE FLOW OFF LAKE MICHIGAN FROM 12Z TUE INTO WED.
THIS SHOULD LEAD TO LES OFF LAKE MI INTO ERN UPPER MI...ESPECIALLY
SERN SCHOOLCRAFT COUNTY. INVERSION HEIGHTS SHOULD BE AROUND 10KFT
ACCORDING TO THE NAM/GFS WITH UNIDIRECTIONAL WINDS. THE RESULTING
LES BAND SHOULD BE A LARGER MORE DOMINANT ONE...BUT SHOULD ALSO NOT
STAY IN ONE PLACE TOO LONG AS WINDS STEADILY VEER. EVEN SO...MAY END
UP BEING CLOSE TO ADVISORY AMOUNTS. WINDS WILL BECOME WLY ENOUGH
BEHIND THE TROUGH BY 06Z WED TO BRING LES TO NW UPPER MI...BUT WINDS
QUICKLY BECOME ANTICYCLONIC BY 12Z WED AS A SFC RIDGE MOVES TO WRN
LAKE SUPERIOR...SO LIGHTER SNOW AMOUNTS ARE EXPECTED THERE.
A SLIGHTLY STRONGER SYSTEM WILL MOVE N OF THE AREA THU AND DRAW
WARMER TEMPS IN THE CWA...BUT NO SIGNIFICANT PRECIP IS EXPECTED.
HIGHS IN THE MID TO UPPER 30S SEEMS REASONABLE. PRETTY QUIET AFTER
THAT UNTIL MODELS INDICATE A MUCH STRONGER LOW PRESSURE SYSTEM
MOVING NEARBY ON SAT. MODELS ARE IN GOOD AGREEMENT FOR HOW FAR OUT
THE SYSTEM IS...SO WILL USE CONSENSUS OF MODELS FOR THE FORECAST
PAST TUE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1239 AM EST SUN DEC 9 2012
EXPECT PREDOMINANT VFR CONDITIONS THRU AT LEAST THIS MRNG AT ALL THE
TAF SITES WITH RDG OF HI PRES/AXIS OF LLVL DRY AIR DOMINATING. THEN
LATER TODAY...APRCH OF LO PRES WL BRING SN AND LOWER CIGS/VSBYS
SW-NE TO UPR MI. TENDED TO SLOW DOWN THE ONSET OF SN/LOWER
CONDITIONS BASED ON NUMERICAL MODEL TRENDS SHOWING A FARTHER S TRACK
FOR THE LO PRES/MORE RESILIENT DRY AIR OVER THE UPR LKS. ALTHOUGH
SAW IS FARTHER TO THE NE...UPSLOPE ESE WIND MIGHT RESULT IN AN
EARLIER ARRIVAL OF THE PCPN/MVFR CIGS. BY EARLY EVNG...CONDITIONS
SHOULD DETERIORATE TO IFR AT ALL 3 LOCATIONS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 340 PM EST SAT DEC 8 2012
AN AREA OF LOW PRESSURE MOVING OUT OF SOUTHWEST SOUTH DAKOTA WILL
ENTER MN TOMORROW MORNING AND THEN MERGE WITH A LOW DEVELOPING IN
THE GREAT LAKES TO LEAVE A TROUGH OVER NORTHERN WISCONSIN. THIS
TROUGH WILL INCREASE WINDS OUT OF THE EAST AND THEN NORTHEAST
DIRECTION SUNDAY INTO SUNDAY NIGHT. AT THIS TIME...THINKING WINDS
WILL BE IN THE 20-30KT RANGE...ALTHOUGH THERE COULD BE A FEW GALE
FORCE GUSTS TO 35KTS OVER THE WEST AS THE TROUGH SHARPENS LATE
SUNDAY NIGHT. BEHIND THIS FEATURE...A SERIES OF WEAK RIDGES AND
TROUGHS WILL AFFECT LAKE SUPERIOR DURING THE REST OF THE WORK WEEK
AND KEEP WINDS BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ006-007-013-014-085.
WINTER WEATHER ADVISORY FROM 10 AM EST /9 AM CST/ THIS MORNING
TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ001-003-004-010-084.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 1 PM EST
MONDAY FOR MIZ005.
WINTER WEATHER ADVISORY FROM 7 AM EST /6 AM CST/ THIS MORNING TO
5 PM EST /4 PM CST/ MONDAY FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM 9 AM SUNDAY TO 3 AM CST MONDAY FOR
MIZ011-012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...SRF
LONG TERM...TITUS
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1135 PM CST SAT DEC 8 2012
.UPDATE...
06Z AVIATION DISCUSSION ADDED BELOW.
&&
.PREV DISCUSSION...
/ISSUED 447 PM CST SAT DEC 8 2012/
..DANGEROUS WINTER STORM TO IMPACT THE UPPER MISSISSIPPI VALLEY
TONIGHT THROUGH SUNDAY NIGHT...
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT.
LOW PRESSURE LOCATED NEAR VALENTINE NEBRASKA LATE THIS AFTERNOON WILL
TRACK ALMOST DUE EAST TONIGHT AND SUNDAY...TRACKING ROUGHLY ALONG
THE I-90 CORRIDOR. THIS IS A SIGNIFICANT SHIFT SOUTH FROM WHAT
MODELS WERE SHOWING YESTERDAY...WITH THE NAM REMAINING THE LONE
NORTHERN OUTLIER TRACKING IT ACROSS THE TWIN CITIES METRO. IN
ADDITION...QPF HAS INCREASED MARKEDLY FROM 00Z RUNS AND NOW
AVERAGES BETWEEN A HALF AND AT LEAST THREE QUARTERS OF AN INCH
FROM WILLMAR TO NEAR LADYSMITH...OR JUST NORTH OF THE METRO.
ELSEWHERE...QPF AVERAGES 0.3 TO 0.5 INCHES. THE 18Z GFS IS COMING
IN SURPRISINGLY HIGH AT NEARLY ONE INCH AND AGAIN JUST A BIT FURTHER
SOUTH FROM PREVIOUS RUNS...NOW THROUGH THE METRO. EVEN THE EC WHICH
WAS THE DRY OUTLIER YESTERDAY IS SHOWING AT LEAST 0.6 INCHES OVER
MUCH OF THE CENTRAL AREAS. MODEL INCONSISTENCY FROM RUN TO RUN
SHOULD NOW BE ABOUT COMPLETE...LEAVING A VERY HIGH PROBABILITY
FOR A MAJOR WINTER STORM ACROSS MUCH OF THE AREA TONIGHT INTO
SUNDAY EVENING.
THE ARC OF SNOW EXPECTED TO PROPAGATE INTO WESTERN MINNESOTA DURING
THE NEXT FEW HOURS IS EXPANDING IN SIZE AND PRODUCING MODERATE TO
HEAVY SNOWFALL RATES WITHIN EMBEDDED BANDS. WITH TIME...THIS AREA
OF SNOW WILL EXPAND WITH WIDESPREAD MODERATE TO HEAVY SNOW
EXPECTED TO SPREAD EAST ACROSS THE AREA LATER THIS EVENING AND
OVERNIGHT. FRONTOGENESIS WITHIN THE DENDRITIC GROWTH ZONE IS
RATHER IMPRESSIVE SO EMBEDDED BANDS OF VERY HEAVY SNOW WITH
GREATER THAN ONE INCH HOURLY RATES ARE POSSIBLE THROUGH SUNDAY
MORNING. BECAUSE THE TRACK OF THE LOW WILL BE CONFINED TO ABOUT
I-90...THE THREAT FOR DRY SLOTTING INTO THE SOUTHERN AREAS IS A
BIT LOWER ALTHOUGH STILL POSSIBLE FOR THE SOUTHERN TWO TIERS OF MN
COUNTIES COME SUNDAY MORNING. STORM TRACK HAS SLOWED A BIT AS
WELL...THUS DEFORMATION SNOW WILL HELP PILE ON THE INCHES A BIT
LONGER THAN ANTICIPATED YESTERDAY. OCCASIONAL SNOW OR SNOW SHOWERS
ARE EXPECTED THROUGH AT LEAST EARLY SUNDAY AFTERNOON AND POSSIBLY
THROUGH THE EVENING OVER WESTERN WISCONSIN.
PREDICTED SNOWFALL AMOUNTS MAY BE CONSERVATIVE IF THE HIGHER QPF
DEPICTIONS PAN OUT...BUT STILL EXPECTING 6 TO 9 INCHES ACROSS
CENTRAL MN AND WESTERN WISCONSIN...AND 3 TO 5 INCHES NEAR THE
IOWA BORDER. COULD SEE SOME ISOLATED TOTALS EXCEED 9 OR 10 INCHES
IN LOCALLY FAVORED BANDING AREAS.
THEREFORE...EXPANDED THE WINTER STORM WARNING SOUTH TO ABOUT A
LINE FROM REDWOOD FALLS...TO RED WING..AND EAU CLAIRE WITH A
WINTER WEATHER ADVISORY SOUTH OF THAT TO THE IOWA BORDER. THESE
HEADLINES DEAL WITH SNOWFALL TOTALS ONLY.
THE BIG CHANGE TO THIS FORECAST PACKAGE WAS TO ISSUE A BLIZZARD
WARNING FROM LATE SUNDAY MORNING THROUGH SUNDAY EVENING WEST OF A
LINE FROM ALEXANDRIA TO WILLMAR AND MANKATO. MODELS HAVE BEEN
CONSISTENT IN SHOWING POTENTIAL FOR 40 KT WINDS WITHIN THE MIXED
LAYER BEHIND THE SYSTEM AND THINK GUSTS TO AT LEAST 35 KTS WILL BE
FREQUENT. COUPLE THAT WITH FRESHLY FALLEN SNOW AND POTENTIALLY
ADDITIONAL LIGHT SNOW...CONFIDENCE HAS INCREASED THAT BLIZZARD
CONDITIONS WILL BE COMMON WITH NEAR ZERO VISIBILITIES IN OPEN
AREAS SUNDAY AFTERNOON AND EARLY EVENING /ESPECIALLY IF GUSTS
EXCEED 45 MPH/. TEMPERATURES WILL PLUMMET BELOW ZERO SUNDAY
EVENING AS WELL...THREATENING THE LIVES OF ANY STUCK TRAVELERS.
KEPT THE BLIZZARD WARNING CONFINED TO AREAS WITH A HIGH
LIKELIHOOD OF AT LEAST 4 INCHES OF SNOW WHICH IS GENERALLY NEEDED
FOR CONSIDERABLE BLOWING AND DRIFTING.
THE SYSTEM WILL PULL OUT SUNDAY NIGHT AS THE RIDGE QUICKLY BUILDS
INTO THE WEST. SOME SNOW IS STILL POSSIBLE OVER WRN WI IN CYCLONIC
FLOW...BUT CLEARING SKIES WILL ALLOW FOR A BITTER COLD NIGHT WITH
LOWS IN THE TEENS BELOW OVER WRN MN AND NEAR ZERO AS FAR EAST AS
I-35. WINDS SHOULD REMAIN ELEVATED ENOUGH TO BRING WIND CHILL
VALUES DOWN INTO THE 20S AND POSSIBLY LOW 30S BELOW NEAR THE SOUTH
DAKOTA BORDER...WITH TEENS BELOW TO I-35. WIND CHILL ADVISORIES
WILL BE NEEDED AFTER THE OTHER WINTER HEADLINES EXPIRE.
WILL REMAIN COLD DESPITE SUNSHINE ON MONDAY UNDER THE RIDGE
AXIS...BUT RETURN FLOW MONDAY EVENING SHOULD KEEP TEMPS STEADY OR
SLOWLY RISE OVERNIGHT. A WEAK SYSTEM PASSING THROUGH THE UPPER
MISSISSIPPI VALLEY TUESDAY COULD BRING A LITTLE LIGHT SNOW OR
FLURRIES WITH NO ACCUMULATIONS ARE EXPECTED.
LONG TERM...WEDNESDAY THROUGH SATURDAY.
UPPER LEVEL RIDGING WILL BE IN PLACE ACROSS THE GULF OF ALASKA BY
MIDWEEK...WITH A DEEP TROUGH DIGGING DOWN THE WEST COAST.
SOUTHWEST FLOW WILL STREAM ACROSS THE CENTRAL CONUS...WITH WARM
AIR ADVECTION SPREADING OVERHEAD ALLOWING HIGH TEMPS TO MAKE A RUN
AT THE THAWING MARK FOR BOTH WEDNESDAY AND THURSDAY. BY FRIDAY A
WELL ESTABLISHED EAST/WEST TEMPERATURE GRADIENT WILL BE IN PLACE
OVER THE UPPER MIDWEST...AND THE AFOREMENTIONED WEST COAST TROUGH
WILL MOVE INLAND OVER THE FOUR CORNERS REGION. THIS WILL BE THE
MAIN PLAYER IN THE WEEKEND WEATHER AS BOTH THE GFS AND ECMWF 08.12
EJECT THIS WAVE TOWARDS THE GREAT LAKES REGION. THIS PV ANOMALY
WILL ACT ON THE LOW LEVEL TEMPERATURE GRADIENT AND CAUSE A SURFACE
CYCLONE TO DEVELOP AND TRACK SOUTH AND EAST OF THE CWA. THIS WOULD
PUT CENTRAL MINNESOTA AND WESTERN WISCONSIN IN A FAVORABLE REGION
FOR ANOTHER POTENTIAL WEEKEND SNOW STORM. FORECAST SOUNDINGS AND
NORTH/SOUTH CROSS SECTIONS VIA THE GFS SHOW A WARM LAYER CENTERED
AROUND H850 WITH THE 0C LINE EXTENDING AS FAR NORTH AS THE METRO
AREA. THEREFORE HAVE INCLUDED THE CHANCE OF MIXED PRECIP FOR
SATURDAY MORNING ACROSS THE SOUTHEAST HALF OF THE CWA WITH THE
INITIAL SURGE OF LOW LEVEL THETA_E ADVECTION...AND THEN TRANSITION
TO ALL SNOW BY THE AFTERNOON. ALSO INCREASED POPS ABOVE GUIDANCE
GIVEN THE REMARKABLE AGREEMENT BY THE LONG RANGE MODELS.
&&
.AVIATION.../06Z TAF ISSUANCE/
SIGNIFICANT SOUTHERN SHIFT ALONG WITH A BIT OF A SLOWING OCCURRED
WITH 00Z MODEL RUNS AND THIS PLACES ALL MPX TERMINALS WITHIN THE
HEART OF WHAT LOOKS TO BE AN IMPRESSIVE SNOW BAND...WITH 6-10 INCH
SNOW TOTALS /AND POSSIBLY MORE AT STC...MSP...RNH/ NOW EXPECTED. SFC
LOW RIGHT NOW IS CENTERED ALONG I-90 NEAR CHAMBERLAIN...SD. 00Z
NAM/GFS ALONG WITH THE RAP TRACK THIS LOW RIGHT DOWN I-90 THROUGH
THE DAY SUNDAY...PLACING THE MPX TERMINALS WITHIN THE HEAVIEST
SNOW. HAVE ALREADY BEEN GETTING SNOWFALL RATES OF AN INCH PLUS PER
HOUR IN WRN MN...SO CONTINUED TO ADVERTISE PROLONGED PERIODS OF
1/2SM VIS AT ALL TERMINALS...BUT TENDED TO SHIFT THAT MENTION OUT
IN TIME WITH THE SLOWING. ANOTHER ASPECT OF THE SLOWING WAS THE
NEED TO SLOW THE BACKING OF WINDS FROM THE EAST OVER TO THE
NW...ALONG WITH A TEMPERING OF SPEEDS SOME...AS NAM NOW SHOWING
GUST POTENTIAL GREATER THAN 35 KTS AT ONLY RWF. AS THIS TAF PERIOD
COMES TO AN END...CLEARING WILL START WORKING INTO WRN MN...WITH
VFR CONDITIONS EXPECTED AS WE START GOING A LITTLE BEYOND THIS TAF
PERIOD.
KMSP...ALL GUIDANCE NOW PUTTING MSP IN THE CROSS-HAIRS FOR THE
HEAVIEST SNOW WITH THIS EVENT...SO SIGNIFICANTLY DEGRADED
TAF...WITH LIFR VIS SNOW NOW EXTENDING WELL OUT INTO THE
AFTERNOON. LOOKING AT THE NAM ALONG WITH CURRENT RADAR...EXPECTING
TWO BURSTS OF SNOW THIS PERIOD. FIRST WILL COME BETWEEN 8Z AND 12Z
AS WARM ADVECTIVE WING OF PRECIP SWINGS THROUGH...WITH THE
NEXT...MORE PROLONGED BOUT OF HEAVY SNOW HITTING BETWEEN 14Z AND
22Z AS THE MAIN UPPER FORCING MOVES IN. THIS IS WHEN MAJORITY OF
ACCUMULATIONS SHOULD OCCUR...WITH SEVERAL OF THESE HOURS LIKELY
SEEING RATES AROUND 1 INCH AN HOUR. THIS TAF MAY A BIT PESSIMISTIC
WITH THE LENGTH OF 1/2SM VIS...BUT FEEL PRETTY CONFIDENT IN
WINDOWS OF HEAVIER SNOW THAT ARE INDICATED WITH TAF. AVIATION
WEATHER WARNING WILL ALSO BE ISSUED SHORTLY FOR ACCUMULATIONS
EXCEEDING 3/4 OF AN INCH PER HOUR. AS FOR STORM TOTAL...WOULD PUT
MSP ON THE HIGHER END OF THE SCALE WITH 8-10 INCHES LOOKING MORE
AND MORE LIKELY.
/OUTLOOK FOR KMSP/
MON...MVFR/IFR CIGS POSSIBLE EARLY. THEN VFR. WINDS WNW AT 10G15KTS.
TUE...MVFR/IFR CIGS POSSIBLE. WINDS SW AT 10G15KTS.
WED...VFR. WINDS SE AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST SUNDAY NIGHT FOR BLUE
EARTH-FARIBAULT-FREEBORN-GOODHUE-LE SUEUR-RICE-STEELE-
WASECA.
WINTER STORM WARNING UNTIL 11 AM CST SUNDAY FOR CHIPPEWA-DOUGLAS-
KANDIYOHI-LAC QUI PARLE-POPE-RENVILLE-SIBLEY-STEVENS-SWIFT-
YELLOW MEDICINE.
BLIZZARD WARNING FROM 11 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT
FOR BROWN-CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-NICOLLET-
POPE-REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE.
WINTER STORM WARNING UNTIL MIDNIGHT CST SUNDAY NIGHT FOR BENTON-
CHISAGO-ISANTI-KANABEC-MCLEOD-MEEKER-MILLE LACS-MORRISON-
SHERBURNE-STEARNS-TODD-WRIGHT.
WINTER STORM WARNING UNTIL MIDNIGHT CST SUNDAY NIGHT FOR ANOKA-
CARVER-DAKOTA-HENNEPIN-RAMSEY-SCOTT-WASHINGTON.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST SUNDAY NIGHT FOR
MARTIN-WATONWAN.
WINTER WEATHER ADVISORY UNTIL 11 AM CST SUNDAY FOR BROWN-
NICOLLET-REDWOOD.
WI...WINTER STORM WARNING UNTIL MIDNIGHT CST SUNDAY NIGHT FOR BARRON-
CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
BORGHOFF/MPG
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1117 PM CST SAT DEC 8 2012
.UPDATE...
ISSUED AT 849 PM CST SAT DEC 8 2012
MUCH OF THE CWA HAS BEEN DRY SO FAR THIS EVENING WITH LOW CLOUDS
AND SOME PATCHY FOG. STILL BELIEVE THAT RAIN CHANCES WILL INCREASE
SIGNIFICANTLY LATER THIS EVENING AND OVER NIGHT AS LARGE SCALE
ASCENT INCREASES AHEAD OF SHORTWAVE MOVING ACROSS THE CENTRAL
PLAINS. RAP HAS BEEN CONSISTENT IN SHOWING AN INCREASE IN LOW
LEVEL MOISTURE CONVERGENCE ALONG 850MB WARM FRONT TONIGHT. ONLY
CHANGE IN FORECAST IS TO REFLECT NEAR TERM PRECIPITATION AND
TEMPERATURE TRENDS.
BRITT
&&
.SHORT TERM...
ISSUED AT 213 PM CST SAT DEC 8 2012
(TONIGHT)
SHORTWAVE DIVING THROUGH EASTERN MONTANA AT THIS TIME IS FORCING
CYCLOGENESIS OVER THE NORTHERN PLAINS. SOUTHWESTERLY LOW LEVEL
FLOW WILL BEGIN TO INCREASE OVER THE LOWER MISSISSIPPI VALLEY
TONIGHT IN RESPONSE TO THE STRENGTHENING LOW. THIS WILL BRING THE
QUASI-STATIONARY FRONT HANGING OVER ARKANSAS BACK NORTH INTO OUR
AREA BY EARLY SUNDAY MORNING. LOW LEVEL JET RAMPS UP AROUND 30KTS
THIS EVENING PRODUCING DECENT 850MB MOISTURE CONVERGENCE OVER THE
AREA. AT FIRST IT`S RATHER WEAK AND DIFFUSE...BUT BECOMES STRONGER
OVER NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS LATE TONIGHT AS
THE 850MB TEMP GRADIENT TIGHTENS UP. EXPECT WIDELY SCATTERED
SHOWERS TO DEVELOP THIS EVENING OVER SOUTHEAST
MISSOURI...OVERSPREADING THE ENTIRE AREA AND INCREASING IN AREAL
COVERAGE IN RESPONSE TO THE INCREASING MOISTURE CONVERGENCE. COULD
SEE A LITTLE THUNDER AS WELL...PRIMARILY OVER SOUTHEAST MISSOURI
AND SOUTHERN ILLINOIS WHERE MUCAPE IS FORECAST TO EXCEED 250 J/KG.
TEMPERATURES WILL TAKE AN INITIAL DIP THIS EVENING...BUT SHOULD
LEVEL OUT AND POSSIBLY RISE SLIGHTLY AS THE WARM FRONT MOVES UP
INTO THE BI-STATE REGION LATE TONIGHT.
CARNEY
&&
.LONG TERM...
ISSUED AT 213 PM CST SAT DEC 8 2012
SUNDAY AND SUNDAY NIGHT...
THE WARM FRONTAL BOUNDARY WILL BE LOCATED ACROSS THE SOUTHERN
PORTION OF THE CWA BY 12Z...WITH THE OVERNIGHT WARM ADVECTION
PRECIPITATION BEGINNING TO LIFT NORTH AND EAST OF THE CWA. THINK
THERE WILL BE A LULL IN THE RAIN BY MIDMORNING ACROSS A GOOD AMOUNT
OF THE CWA UNTIL A STRONG COLD FRONT MOVES SOUTHEAST ACROSS THE AREA
IN THE AFTERNOON AND EVENING. THIS FRONT WILL REINFORCE THE
BAROCLINICITY TO OUR SOUTHEAST AND LEAD TO LIGHT RAIN REDEVELOPING
ACROSS AT LEAST THE SOUTHEAST HALF OF THE CWA FOR THE AFTERNOON AND
EARLY EVENING HOURS. LUCKILY...ALL INDICATIONS ARE THAT THE RAIN
WILL TURN TO COLD SUNDAY NIGHT AS DEEP MOISTURE IS SHUNTED TO THE
SOUTHEAST AS THE WINTER BLAST ARRIVES AND COLD AIR DEEPENS ACROSS
THE CWA.
MONDAY THROUGH THURSDAY...
A RAW WINTER DAY IS ON TAP FOR MONDAY AS TEMPERATURES STRUGGLE TO
RISE BACK ABOVE FREEZING WITH STRONG COLD ADVECTION AND A GUSTY
NORTHWEST WIND. THE WINTER CHILL SHOULD BE BRIEF THOUGH...AS
TEMPERATURES WILL ALREADY BEGIN MODERATING BY MIDWEEK DESPITE A TROF
MOVING ACROSS THE MIDWEST. TEMPERATURES WILL RISE BACK ABOVE NORMAL
FOR THE END OF THE WEEK AS THE UPPER FLOW BECOMES SOUTHWEST IN
RESPONSE TO A STRONG STORM SYSTEM DIGGING SOUTH ALONG THE WEST COAST.
FRIDAY THROUGH SATURDAY...
NEARLY ALL OF THE MEDIUM RANGE GUIDANCE DEPICTS A STRONG SHORTWAVE
AND SURFACE LOW PASSING TO THE WEST OF THE CWA FRIDAY NIGHT. THIS
PATTERN IS INDICATIVE OF ABOVE NORMAL TEMPERATURES AND A GOOD CHANCE
OF SHOWERS AND THUNDERSTORMS.
CVKING
&&
.AVIATION...
ISSUED AT 1033 PM CST SAT DEC 8 2012
STRATUS CLOUDS WERE SLOWLY LOWERING THIS EVNG...EXCEPT AT UIN
WHERE RAIN DEVELOPED AND CAUSED THE CEILINGS TO TEMPORARILY RISE.
THE CEILING AT UIN SHOULD LOWER AGAIN LATE TGT BEFORE THE NEXT
ROUND OF RAIN MOVES IN. MORE LIGHT RAIN WILL DEVELOP LATE TGT AS
THE STATIONARY FRONT ACROSS NRN AR LIFTS BACK NWD INTO SRN MO AND
A SWLY LOW LEVEL JET BRINGS INCREASING AND DEEPENING LOW LEVEL
MOISTURE INTO THE AREA. CEILINGS WILL LIKELY LOWER TO 500 TO
1000 FT WITH VSBYS OF 2-4SM IN LIGHT RAIN AND FOG. E-SELY SFC
WIND WILL CONTINUE LATE TGT. THE RAIN SHOULD END IN UIN AND COU BY
LATE SUN MRNG AS A SFC WAVE ALONG THE FRONT MOVES E OF THE
AREA...WHILE A STRONG COLD FRONT DROPS SEWD INTO THE REGION. RAIN
WILL LIKELY CONTINUE IN THE ST LOUIS METRO AREA SUN AFTN UNTIL THE
COLD FRONT MOVES SE OF THE AREA WITH CAA AND DRYING OF THE LOW
LEVELS BEHIND THE COLD FRONT. THE SFC WIND WILL VEER AROUND TO A
NWLY DIRECTION AS THE SFC WAVE SHIFTS E OF THE AREA...AND THEN
STRENGTHENS AFTER PASSAGE OF THE STRONG COLD FRONT SUN AFTN. WILL
SEE AN IMPROVEMENT IN VSBYS LATE SUN MRNG AND AFTN...BUT ONLY A
VERY GRADUAL RISE IN CEILING HEIGHTS WITH CIGS RISING TO AROUND
1000 FT BY EARLY AFTN. THE CEILING WILL CONTINUE TO RISE...INTO
THE MVFR CATAGORY BY LATE AFTN AND TO THE VFR CATAGORY SUN EVNG.
SPECIFICS FOR KSTL...CIG HEIGHTS SHOULD CONTINUE TO LOWER LATE TGT
WITH FOG DEVELOPING. THE CIGS SHOULD LOWER TO AROUND 500-1000 FT
LATE TGT WITH VSBYS FALLING TO AROUND 2-4SM AS LIGHT RAIN MOVES
INTO THE AREA. AN E-SELY SFC WIND WILL CONTINUE LATE TGT AS A SFC
RIDGE SHIFTS WELL NE OF OUR AREA WHILE A WARM FRONT APPROACHES STL
FROM THE S. THE RAIN SHOULD END BY SUN EVNG AS A SFC WAVE ALONG
THIS FRONT SHIFTS WELL NE OF STL AND A STRONG COLD FRONT MOVES SE
OF STL CAUSING THE SFC WIND TO VEER AROUND TO A W-NWLY DIRECTION
AND STRENGTHEN DURING THE AFTN AND EVNG HOURS. THE VSBYS WILL
IMPROVE DURING THE LATE MRNG AND AFTN HOURS WITH THE CLOUD CEILING
RISING TO AROUND 1000 FT BY AFTN AND 1500 FT BY SUN EVNG. THE
CEILING SHOULD FINALY RISE INTO THE VFR CATAGORY LATE SUN NGT.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1120 PM CST SAT DEC 8 2012
.AVIATION...FOR THE KLBF AND KVTN TERMINALS THROUGH 06Z MONDAY.
AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL TRACK ACROSS THE CENTRAL
AND NORTHERN PLAINS OVER THE NEXT 24 HOURS...LEADING TO ABUNDANT
CLOUDINESS AND WINDY CONDITIONS ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA THROUGH SUNDAY AFTERNOON. AT THE KLBF TERMINAL...EXPECT
CIGS AON 10000 FT AGL THROUGH 13Z SUNDAY MORNING...DROPPING DOWN TO
AROUND 3000 FT AGL. CIGS WILL BEGIN TO SCATTER OUT AFTER 22Z
SUNDAY...CLEARING OUT SUNDAY EVENING. AT THE KVTN TERMINAL...LIGHT
SNOW IS EXPECTED OVER THE NEXT 2 TO 4 HOURS...AND IS EXPECTED TO
EXIT THE TERMINAL AFTER 10Z SUNDAY. CIGS WILL REMAIN AON 1500 FT AGL
THROUGH SUNDAY MORNING...RISING TO 2500 FT AGL. SKIES WILL SCATTER
OUT SUNDAY AFTERNOON...CLEARING SUNDAY EVENING. STRONG NORTHERLY
WINDS OF 20 TO 25 KTS...WITH GUSTS UP TO 33 KTS ARE LIKELY FOR THE
REST OF TONIGHT THROUGH SUNDAY AFTERNOON. WINDS WILL QUICKLY
DIMINISH SUNDAY EVENING AFTER SUNDOWN.
&&
.PREV DISCUSSION... /ISSUED 1009 PM CST SAT DEC 8 2012/
UPDATE...BASED ON PRESSURE TRENDS ACROSS EASTERN SOUTH DAKOTA AND
THE LATEST NAM AND MAV GUIDANCE...DECIDED TO HOIST A WIND ADVISORY
FOR SUNDAY MORNING THROUGH SUNDAY AFTERNOON ACROSS A LARGE PORTION
OF NORTH CENTRAL AND CENTRAL NEBRASKA. STRONG PRESSURE RISES OF 3 TO
6 MB/3HR WILL TRACK FROM NORTH CENTRAL NEBRASKA INTO NORTHEASTERN
NEBRASKA FROM 12Z THROUGH 18Z SUNDAY. WINDS WILL PEAK AROUND NOON
TIME...THEN SLOWLY DECLINE INTO THE LATE AFTERNOON HOURS. IN
ADDITION TO STRONG WINDS...HIGHS SUNDAY WILL BE IN THE TEENS AND
20S...PRODUCING WIND CHILLS OF ZERO TO MINUS 10 IN THE ADVISORY
AREA. STILL WELL ABOVE CRITERIA FOR A WIND CHILL ADVISORY...BUT
WORTH MENTIONING IN THE HWO AND NPW/WIND ADVISORY PRODUCT. BULK OF
THE SNOW WILL REMAIN NORTH OF THE BORDER OVERNIGHT WITH ONLY A
DUSTING EXPECTED ALONG THE NEBR/SD BORDER.
&&
.PREV DISCUSSION... /ISSUED 606 PM CST SAT DEC 8 2012/
AVIATION...FOR THE KLBF AND KVTN TERMINALS THROUGH 00Z MONDAY.
AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL TRACK ACROSS THE CENTRAL
AND NORTHERN PLAINS OVER THE NEXT 24 HOURS...LEADING TO ABUNDANT
CLOUDINESS AND WINDY CONDITIONS ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA. AT THE KLBF TERMINAL...EXPECT CIGS AON 10000 FT AGL
THROUGH 10Z TONIGHT...DROPPING DOWN TO AROUND 4000 FT AGL. CIGS WILL
BEGIN TO SCATTER OUT AFTER 17Z SATURDAY. AT THE KVTN TERMINAL...CIGS
WILL DROP FROM 5000 FT AGL DOWN TO 1500 FT AGL OVERNIGHT AND REMAIN
THERE THROUGH MIDDAY SUNDAY. SKIES WILL BEGIN TO SCATTER OUT BY LATE
AFTERNOON. FOR BOTH TERMINALS...LOOK FOR NORTHERLY WINDS TO INCREASE
TO 15 TO 25 KTS TONIGHT WITH PERIODIC GUSTS TO AROUND 30 KTS AT BOTH
TERMINALS. WINDS WILL GRADUALLY DIMINISH LATE SUNDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 244 PM CST SAT DEC 8 2012/
...MUCH COLDER WITH WINDY CONDITIONS LATE TONIGHT AND SUNDAY...
SYNOPSIS... SURFACE LOW PRESSURE RESIDES ACROSS THE CENTRAL HIGH
PLAINS WITH MAIN LOW FORMING NEAR PINE RIDGE SOUTH DAKOTA. LEADING
EDGE OF COLD FRONT JUST PASSED CHADRON. STEEP LAPSE RATES
ATTRIBUTING TO CONVECTIVE SNOW SHOWERS PANHANDLE INTO NORTH
CENTRAL. MUCH OF RADAR ECHOES NOT REACHING GROUND EFFECTIVELY DUE
TO FAIRLY LARGE TEMPERATURES AND DEWPOINT SPREAD. NEVERTHELESS...
THIS HAS BEEN MOISTENING UP THE ATMOSPHERE FOR UPSTREAM
DEVELOPMENT TO TAKE ADVANTAGE OF FOR LATE AFTERNOON INTO THIS
EVENING.
DISCUSSION...
SHORT TERM...TONIGHT THROUGH TUESDAY. MAIN FORECAST CONCERNS OVER
THE NEXT 36 HOURS INVOLVES THE THREAT OF LIGHT SNOW...A RETURN OF
COLD TEMPERATURES...AND THE POTENTIAL OF ADVISORY CRITERIA WIND
SPEEDS.
MODELS CONTINUE TO SHOW GOOD AGREEMENT IN THE NEAR TERM IN WHICH THE
SHORTWAVE TROUGH CURRENTLY LOCATED FROM CENTRAL SOUTH DAKOTA INTO
EASTERN MONTANA AND ASSOCIATED SURFACE LOW DEEPEN AND EJECT EAST
ACROSS THE NORTHERN PLAINS...DRAGGING A STRONG COLD FRONT THROUGH
THE CWA OVERNIGHT TONIGHT. THE RAP MODEL CONTINUES TO INDICATE THE
SURFACE LOW NEAR AND SOUTH OF I90 TONIGHT WHICH REMAINS FARTHER SOUTH
THAN OTHER SHORT TERM MODELS. AN H3 JET MAX ACROSS NORTHERN
COLORADO AND SOUTHERN NEBRASKA THIS EVENING WILL BE FAVORABLE FOR
ASCENT IN THE LEFT EXIT REGION OF JET ACROSS NORTH CENTRAL
NEBRASKA. AS SUGGESTED BY THE RAP MODEL...REGIONAL GEM AND TO A
LESSER EXTEND THE NAM...BANDED SNOWFALL IS FAVORABLE FROM NEAR
MULLEN THROUGH BASSETT. LOCAL SNOWFALL AMOUNTS NEAR AN INCH
POSSIBLE IN THESE BANDED AREAS. OTHERWISE...LIGHT SNOW ALSO
FORECAST TO DEVELOP AND DROP SOUTH INTO FAR NORTHERN NEBRASKA LATE
TONIGHT INTO SUNDAY MORNING. THIS IS WITHIN SOUTHERN PERIPHERY OF
DEFORMATION ZONE TO BE ACROSS EASTERN SOUTH DAKOTA INTO SOUTH
CENTRAL SOUTH DAKOTA. ANY ASSOCIATED SNOWFALL WOULD REMAIN A HALF
INCH OR LESS. ACROSS THE SOUTHERN HALF OF FORECAST AREA...ANY
LINGERING SNOW OR FLURRIES FROM THIS EVENING SHOULD END SOON
AFTER MIDNIGHT.
STRONG COLD AIR ADVECTION AND LOW LEVEL PRESSURE RISES WILL
FOLLOW THE SURFACE BOUNDARY PASSAGE OVERNIGHT TONIGHT. THE
PRESSURE RISES WILL HELP TIGHTEN THE SURFACE GRADIENT AND ALLOW
FOR GUSTY CONDITIONS LATER TONIGHT INTO SUNDAY. THE MODELS HAVE
SHOWN A SLIGHT SOUTHWARD TREND IN THE TRACK OF THE SURFACE
LOW...NOW ACROSS FAR SOUTHWEST MINNESOTA. THIS TRACK FAVORS
SLIGHTLY STRONGER SURFACE WINDS THAN PREVIOUSLY ANTICIPATED. WILL
KEEP WIND SPEEDS JUST BELOW ADVISORY CRITERIA...ESPECIALLY SINCE
THE STRONGEST PRESSURE RISES ARE EXPECTED DURING THE EARLY MORNING
HOURS...DIURNALLY UNFAVORABLE FOR ADVISORY CRITERIA WIND.
BUT...WIDESPREAD SUB ZERO WIND CHILLS WILL OCCUR...WITH THE
POTENTIAL OF SOME OF THE LOWEST READINGS APPROACHING MINUS TEN OR
COLDER THROUGH SUNDAY MORNING ACROSS OUR NORTHERN ZONES. HIGHS ON
SUNDAY WILL BE COLD...WITH READINGS TRENDED DOWN TO NEAR 15 AT
VALENTINE TO THE MID 20S FAR SOUTH. WE WILL NEED TO WATCH LOW
TEMPERATURES FOR MONDAY MORNING...AS ANY SNOWFALL WOULD ALLOW
READINGS TO PLUMMET...TO POSSIBLY BELOW ZERO. CURRENT FORECAST HAS
LOWS 1 TO 5 ABOVE MOST AREAS...AS WIDESPREAD ACCUMULATING SNOW IS
NOT ANTICIPATED. TEMPERATURES BEGIN TO MODERATE SLOWLY MONDAY
AFTERNOON AS WEAK WAA INFILTRATES FROM THE WEST IN ADVANCE OF THE
NEXT SHORTWAVE TROUGH. HIGHS TO RANGE IN THE 30S. THEN A WESTERLY
DOWNSLOPE TUESDAY TO WARM READINGS TO THE MID 30S TO LOWER 40S.
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY. SHORTWAVE RIDGING AND
WAA TAKE HOLD WEDNESDAY THROUGH THURSDAY...WITH TEMPERATURES SLIGHTLY
ABOVE SEASONAL NORMS WEDNESDAY AND NEAR NORMAL THURSDAY. WILL NEED
TO MONITOR IF A BACK DOOR COLD FRONT DROPS INTO NORTH CENTRAL
NEBRASKA THURSDAY. THE ECMWF AND GEM KEEP COLDER AIR TO THE NORTH
INTO SOUTH DAKOTA...WHILE THE GFS BRINGS IT SOUTH INTO NORTHERN
NEBRASKA. THE NEXT SIGNIFICANT TROUGH IS SHOWN TO REACH THE FOUR
CORNERS REGION 12Z FRIDAY AND TRACK INTO NORTHWEST MISSOURI AS A
NEGATIVELY TILTED CLOSED LOW BY 12Z SATURDAY PER THE ECMWF
SOLUTION. THE GFS ALSO INDICATES A NEGATIVELY TILTED
TROUGH...ALTHOUGH AS AN OPEN WAVE FROM WESTERN SOUTH DAKOTA INTO
NORTHERN NEBRASKA. PRECIPITATION CHANCES NOW BROUGHT INTO EASTERN
NEBRASKA FRIDAY NIGHT INCLUDING FAR EASTERN PORTIONS OF NORTH
CENTRAL NEBRASKA. HIGHS FRIDAY FORECAST TO RANGE IN THE 30S AND
MID 30S TO LOW 40S SATURDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY IN EFFECT FROM 4 AM
CST SUNDAY MORNING THROUGH 5 PM CST SUNDAY AFTERNOON FOR ZONES
NEZ005>010-025>029-037-038.
&&
$$
SHORT TERM/EXTENDED...ROBERG
AVIATION AND UPDATE...BUTTLER
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1009 PM CST SAT DEC 8 2012
.UPDATE...BASED ON PRESSURE TRENDS ACROSS EASTERN SOUTH DAKOTA AND
THE LATEST NAM AND MAV GUIDANCE...DECIDED TO HOIST A WIND ADVISORY
FOR SUNDAY MORNING THROUGH SUNDAY AFTERNOON ACROSS A LARGE PORTION
OF NORTH CENTRAL AND CENTRAL NEBRASKA. STRONG PRESSURE RISES OF 3 TO
6 MB/3HR WILL TRACK FROM NORTH CENTRAL NEBRASKA INTO NORTHEASTERN
NEBRASKA FROM 12Z THROUGH 18Z SUNDAY. WINDS WILL PEAK AROUND NOON
TIME...THEN SLOWLY DECLINE INTO THE LATE AFTERNOON HOURS. IN
ADDITION TO STRONG WINDS...HIGHS SUNDAY WILL BE IN THE TEENS AND
20S...PRODUCING WIND CHILLS OF ZERO TO MINUS 10 IN THE ADVISORY
AREA. STILL WELL ABOVE CRITERIA FOR A WIND CHILL ADVISORY...BUT
WORTH MENTIONING IN THE HWO AND NPW/WIND ADVISORY PRODUCT. BULK OF
THE SNOW WILL REMAIN NORTH OF THE BORDER OVERNIGHT WITH ONLY A
DUSTING EXPECTED ALONG THE NEBR/SD BORDER.
&&
.PREV DISCUSSION... /ISSUED 606 PM CST SAT DEC 8 2012/
AVIATION...FOR THE KLBF AND KVTN TERMINALS THROUGH 00Z MONDAY.
AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL TRACK ACROSS THE CENTRAL
AND NORTHERN PLAINS OVER THE NEXT 24 HOURS...LEADING TO ABUNDANT
CLOUDINESS AND WINDY CONDITIONS ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA. AT THE KLBF TERMINAL...EXPECT CIGS AON 10000 FT AGL
THROUGH 10Z TONIGHT...DROPPING DOWN TO AROUND 4000 FT AGL. CIGS WILL
BEGIN TO SCATTER OUT AFTER 17Z SATURDAY. AT THE KVTN TERMINAL...CIGS
WILL DROP FROM 5000 FT AGL DOWN TO 1500 FT AGL OVERNIGHT AND REMAIN
THERE THROUGH MIDDAY SUNDAY. SKIES WILL BEGIN TO SCATTER OUT BY LATE
AFTERNOON. FOR BOTH TERMINALS...LOOK FOR NORTHERLY WINDS TO INCREASE
TO 15 TO 25 KTS TONIGHT WITH PERIODIC GUSTS TO AROUND 30 KTS AT BOTH
TERMINALS. WINDS WILL GRADUALLY DIMINISH LATE SUNDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 244 PM CST SAT DEC 8 2012/
...MUCH COLDER WITH WINDY CONDITIONS LATE TONIGHT AND SUNDAY...
SYNOPSIS... SURFACE LOW PRESSURE RESIDES ACROSS THE CENTRAL HIGH
PLAINS WITH MAIN LOW FORMING NEAR PINE RIDGE SOUTH DAKOTA. LEADING
EDGE OF COLD FRONT JUST PASSED CHADRON. STEEP LAPSE RATES
ATTRIBUTING TO CONVECTIVE SNOW SHOWERS PANHANDLE INTO NORTH
CENTRAL. MUCH OF RADAR ECHOES NOT REACHING GROUND EFFECTIVELY DUE
TO FAIRLY LARGE TEMPERATURES AND DEWPOINT SPREAD. NEVERTHELESS...
THIS HAS BEEN MOISTENING UP THE ATMOSPHERE FOR UPSTREAM
DEVELOPMENT TO TAKE ADVANTAGE OF FOR LATE AFTERNOON INTO THIS
EVENING.
DISCUSSION...
SHORT TERM...TONIGHT THROUGH TUESDAY. MAIN FORECAST CONCERNS OVER
THE NEXT 36 HOURS INVOLVES THE THREAT OF LIGHT SNOW...A RETURN OF
COLD TEMPERATURES...AND THE POTENTIAL OF ADVISORY CRITERIA WIND
SPEEDS.
MODELS CONTINUE TO SHOW GOOD AGREEMENT IN THE NEAR TERM IN WHICH THE
SHORTWAVE TROUGH CURRENTLY LOCATED FROM CENTRAL SOUTH DAKOTA INTO
EASTERN MONTANA AND ASSOCIATED SURFACE LOW DEEPEN AND EJECT EAST
ACROSS THE NORTHERN PLAINS...DRAGGING A STRONG COLD FRONT THROUGH
THE CWA OVERNIGHT TONIGHT. THE RAP MODEL CONTINUES TO INDICATE THE
SURFACE LOW NEAR AND SOUTH OF I90 TONIGHT WHICH REMAINS FARTHER SOUTH
THAN OTHER SHORT TERM MODELS. AN H3 JET MAX ACROSS NORTHERN
COLORADO AND SOUTHERN NEBRASKA THIS EVENING WILL BE FAVORABLE FOR
ASCENT IN THE LEFT EXIT REGION OF JET ACROSS NORTH CENTRAL
NEBRASKA. AS SUGGESTED BY THE RAP MODEL...REGIONAL GEM AND TO A
LESSER EXTEND THE NAM...BANDED SNOWFALL IS FAVORABLE FROM NEAR
MULLEN THROUGH BASSETT. LOCAL SNOWFALL AMOUNTS NEAR AN INCH
POSSIBLE IN THESE BANDED AREAS. OTHERWISE...LIGHT SNOW ALSO
FORECAST TO DEVELOP AND DROP SOUTH INTO FAR NORTHERN NEBRASKA LATE
TONIGHT INTO SUNDAY MORNING. THIS IS WITHIN SOUTHERN PERIPHERY OF
DEFORMATION ZONE TO BE ACROSS EASTERN SOUTH DAKOTA INTO SOUTH
CENTRAL SOUTH DAKOTA. ANY ASSOCIATED SNOWFALL WOULD REMAIN A HALF
INCH OR LESS. ACROSS THE SOUTHERN HALF OF FORECAST AREA...ANY
LINGERING SNOW OR FLURRIES FROM THIS EVENING SHOULD END SOON
AFTER MIDNIGHT.
STRONG COLD AIR ADVECTION AND LOW LEVEL PRESSURE RISES WILL
FOLLOW THE SURFACE BOUNDARY PASSAGE OVERNIGHT TONIGHT. THE
PRESSURE RISES WILL HELP TIGHTEN THE SURFACE GRADIENT AND ALLOW
FOR GUSTY CONDITIONS LATER TONIGHT INTO SUNDAY. THE MODELS HAVE
SHOWN A SLIGHT SOUTHWARD TREND IN THE TRACK OF THE SURFACE
LOW...NOW ACROSS FAR SOUTHWEST MINNESOTA. THIS TRACK FAVORS
SLIGHTLY STRONGER SURFACE WINDS THAN PREVIOUSLY ANTICIPATED. WILL
KEEP WIND SPEEDS JUST BELOW ADVISORY CRITERIA...ESPECIALLY SINCE
THE STRONGEST PRESSURE RISES ARE EXPECTED DURING THE EARLY MORNING
HOURS...DIURNALLY UNFAVORABLE FOR ADVISORY CRITERIA WIND.
BUT...WIDESPREAD SUB ZERO WIND CHILLS WILL OCCUR...WITH THE
POTENTIAL OF SOME OF THE LOWEST READINGS APPROACHING MINUS TEN OR
COLDER THROUGH SUNDAY MORNING ACROSS OUR NORTHERN ZONES. HIGHS ON
SUNDAY WILL BE COLD...WITH READINGS TRENDED DOWN TO NEAR 15 AT
VALENTINE TO THE MID 20S FAR SOUTH. WE WILL NEED TO WATCH LOW
TEMPERATURES FOR MONDAY MORNING...AS ANY SNOWFALL WOULD ALLOW
READINGS TO PLUMMET...TO POSSIBLY BELOW ZERO. CURRENT FORECAST HAS
LOWS 1 TO 5 ABOVE MOST AREAS...AS WIDESPREAD ACCUMULATING SNOW IS
NOT ANTICIPATED. TEMPERATURES BEGIN TO MODERATE SLOWLY MONDAY
AFTERNOON AS WEAK WAA INFILTRATES FROM THE WEST IN ADVANCE OF THE
NEXT SHORTWAVE TROUGH. HIGHS TO RANGE IN THE 30S. THEN A WESTERLY
DOWNSLOPE TUESDAY TO WARM READINGS TO THE MID 30S TO LOWER 40S.
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY. SHORTWAVE RIDGING AND
WAA TAKE HOLD WEDNESDAY THROUGH THURSDAY...WITH TEMPERATURES SLIGHTLY
ABOVE SEASONAL NORMS WEDNESDAY AND NEAR NORMAL THURSDAY. WILL NEED
TO MONITOR IF A BACK DOOR COLD FRONT DROPS INTO NORTH CENTRAL
NEBRASKA THURSDAY. THE ECMWF AND GEM KEEP COLDER AIR TO THE NORTH
INTO SOUTH DAKOTA...WHILE THE GFS BRINGS IT SOUTH INTO NORTHERN
NEBRASKA. THE NEXT SIGNIFICANT TROUGH IS SHOWN TO REACH THE FOUR
CORNERS REGION 12Z FRIDAY AND TRACK INTO NORTHWEST MISSOURI AS A
NEGATIVELY TILTED CLOSED LOW BY 12Z SATURDAY PER THE ECMWF
SOLUTION. THE GFS ALSO INDICATES A NEGATIVELY TILTED
TROUGH...ALTHOUGH AS AN OPEN WAVE FROM WESTERN SOUTH DAKOTA INTO
NORTHERN NEBRASKA. PRECIPITATION CHANCES NOW BROUGHT INTO EASTERN
NEBRASKA FRIDAY NIGHT INCLUDING FAR EASTERN PORTIONS OF NORTH
CENTRAL NEBRASKA. HIGHS FRIDAY FORECAST TO RANGE IN THE 30S AND
MID 30S TO LOW 40S SATURDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY IN EFFECT FROM 4 AM
CST SUNDAY MORNING THROUGH 5 PM CST SUNDAY AFTERNOON FOR ZONES
NEZ005>010-025>029-037-038.
&&
$$
SHORT TERM/EXTENDED...ROBERG
AVIATION AND UPDATE...BUTTLER
AREA FORECAST DISCUSSION
NWS RALEIGH NC
255 AM EST SUN DEC 9 2012
.SYNOPSIS...
A WARM MOIST SOUTHERLY FLOW AHEAD OF AN APPROACHING COLD FRONT WILL
RESULT IN ABOVE NORMAL TEMPERATURES THROUGH MONDAY. THE COLD FRONT
WILL CROSS THE REGION MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 920 PM SATURDAY...
THE MAIN UPDATES TO THE FORECAST THIS EVENING WILL BE TO ADDRESS
CLOUD COVER AND RAPIDLY FALLING TEMPS. MID CLOUDS UPSTREAM EARLIER
THIS EVENING WERE MORE ROBUST AND EVENING PRODUCING SOME VERY LIGHT
PRECIP OVER SOUTHWESTERN NC...BUT HAVE SINCE DECREASED IN COVERAGE
AS THEY DRIFT SOUTHWEST TO NORTHEAST ACROSS THE AREA. IN AREAS
WHERE SKIES HAVE BEEN MOSTLY CLEAR...PARTICULARLY OVER THE EASTERN
HALF OF THE CWA...TEMPS HAVE QUICKLY FALLEN INTO THE UPPER 40S AND
LOWER 50S. THE LATEST RAP CONTINUES TO INDICATE MOISTURE UPSTREAM
INTO THE AREA WITH A PERIOD OF ISENTROPIC LIFT SUFFICIENT FOR
SCATTERED SHOWERS...MAINLY AROUND THE WESTERN PIEDMONT. DUE TO THE
EXPECTED INCREASE IN MID LEVEL CLOUD COVER...IN THE 4000-6000 FT
RANGE BASED ON UPSTREAM OBS AND FORECAST SOUNDINGS...THERE IS STILL
SOME UNCERTAINTY REGARDING THE COVERAGE OF FOG/STRATUS. WHERE SKIES
ARE CLEAR...VISIBILITIES HAVE FALLEN INTO THE 3 TO 6 MILE RANGE IN
SOME SPOTS...BUT NO FURTHER. WILL CONTINUE TO MONITOR THESE TRENDS
TO SEE IF A DENSE FOG ADVISORY IS NEED LATER TONIGHT....BUT CURRENT
THINKING IS THAT IT MAY BE MORE LIKELY OVER EASTERN AREAS.
WITH TEMPS APPROACHING FORECAST MINS IN SOME OUTLYING AREAS...ALSO
IN RESPONSE TO THE CLEAR SKIES...WILL LOWER MIN TEMPS A COUPLE
DEGREES. HOWEVER...IF CLOUDS MOVE IN AS EXPECTED...TEMPS SHOULD
BEGIN TO LEVEL OUT AND REMAIN IN THE UPPER 40S AND LOWER 50S. -BLS
AFTER THE MORNING LOW CLOUDS/FOG LIFT AND DISPERSE AND ISOLATED
SHOWER ACTIVITY EXITS THE AREA...A MIX OF SUN AND CLOUDS WILL
SUPPORT DAYTIME HIGHS IN THE MID TO UPPER 60S NORTH TO LOWER/MID 70S
SOUTH.
THE UPSTREAM TROUGH WILL BEGIN TO DIG INTO THE SOUTHERN PLAINS
SUNDAY NIGHT WITH ATTENDANT SFC COLD FRONT ADVANCING EAST INTO THE
TN VALLEY. RISING PWATS FROM STRENGTHENING WARM MOIST AIR
ADVECTION...INCREASING RIGHT-ENTRANCE REGION DYNAMICS...THE
POTENTIAL FOR WEAK INSTABILITY ALOFT ALONG WITH THE PROSPECTS OF
SOME WEAK SHORTWAVE DISTURBANCES TO MOVE THROUGH THE AREA IN THE
SWLY FLOW ALOFT WILL SUPPORT ISOLATED SHOWERS...MAINLY IN THE WEST
LATE SUNDAY NIGHT.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM SUNDAY...
THE FAVORED EC MODEL CONTINUES TO SHOW LESS AND LESS IN THE WAY OF
SIGNIFICANT RAIN FOR CENTRAL NC WITH THE PASSAGE OF THE COLD FRONT
MONDAY NIGHT AND TUESDAY. EVEN TUESDAY IS MOSTLY DRY NOW WITH VERY
LITTLE IN THE WAY OF ANY POST-FRONTAL RAIN NOW FORECAST. THESE
TRENDS ARE SUPPORTED BY THE OPERATIONAL GFS/NAM.
TIMING OF THE FRONT... THE FRONT STILL APPEARS ON TARGET TO REACH
INTO THE NW PIEDMONT BY AROUND SUNSET MONDAY NIGHT. OUT AHEAD OF THE
FRONT... WARM AND BREEZY CONDITIONS ARE EXPECTED. HIGHS SHOULD
THREATEN DAILY RECORDS. SEE THE LIST BELOW IN THE CLIMATE SECTION.
THEN... A LINE OF SHOWERS IS EXPECTED TO PRECEDE THE FRONT INTO THE
WESTERN PIEDMONT BY SUNSET... THEN DIE OUT AS IT MOVES INTO THE MORE
STABLE AIR OUT OVER THE PIEDMONT. WE WILL KEEP LIKELY POP FOR LATE
MON AND MON EVENING IN THE WEST... WITH ONLY CHANCE POPS EAST.
THERE IS STILL A CHANCE OF SHOWERS INTO EARLY TUESDAY... OR PATCHY
LIGHT RAIN... BUT QPF SHOULD BE LESS THAN 0.25 FOR THE EVENT FOR
CENTRAL NC. LOCALLY UP TO 0.50 MAY FALL JUST TO OUR WEST IN THE
FOOTHILLS.
EXPECT SKIES TO BECOME PARTLY SUNNY TUESDAY... BREEZY AND COOLER.
HIGHS IN THE 50S.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
THE LATEST MODELS ARE COMING MORE IN LINE WITH A SOLUTION THAT KEEPS
THE BEST CHANCE OF SIGNIFICANT RAIN ALONG THE COAST WEDNESDAY AND
WEDNESDAY NIGHT. EVEN THE LATEST AND FAVORED OPERATIONAL EUROPEAN
MODEL KEEPS THE BEST RAIN ALONG THE COAST AND OFFSHORE WHERE THE
MAIN WAVES OF LOW PRESSURE FORM ALONG THE BAROCLINIC ZONE. IT IS
LOOKING MORE AND MORE LIKE A DRY WEEK FOR CENTRAL NC.
WE WILL MAINTAIN A CHANCE OF RAIN IN THE EAST LATE TUESDAY NIGHT AND
WEDNESDAY... WITH ONLY A SLIGHT CHANCE INTO THE SE PIEDMONT AND
COASTAL PLAIN. OTHERWISE... GENERALLY DRY WEATHER IS EXPECTED
TUESDAY... THURSDAY AND FRIDAY WITH COOLER TEMPS BACK TOWARD
SEASONAL NORMALS.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 235 AM SUNDAY...
24-HR TAF PERIOD:
A FAIR AMOUNT OF UNCERTAINTY PERSISTS WITH REGARD TO HOW LOW
CEILINGS AND VISBYS WILL FALL THROUGH 12Z THIS MORNING. INCREASING
LOW AND MID-LEVEL CLOUD COVER SHOULD PREVENT VISBYS LOWER THAN
MVFR/IFR IN MOST LOCATIONS...EXCEPT PERHAPS AT THE RWI AND FAY
TERMINALS. REGARDLESS OF VISBYS...MVFR/IFR CEILINGS WILL BE POSSIBLE
AT THE RDU/INT/GSO TERMINALS BETWEEN 06-12Z...PRIMARILY AT INT/GSO
WHERE ELEVATED SHOWER ACTIVITY WILL BE POSSIBLE. EXPECT SUB-VFR FOG
OR CEILINGS TO LIFT AND IMPROVE BETWEEN 12-15Z...WITH VFR CONDITIONS
LIKELY IN MOST AREAS BY 15-18Z...EXCEPT PERHAPS AT THE INT/GSO
TERMINALS WHERE MVFR CEILINGS MAY PERSIST INTO THE AFTERNOON.
CEILINGS ARE EXPECTED TO DETERIORATE TO LIFR BETWEEN 03-12Z MONDAY
AS SOUTHWESTERLY FLOW ADVECTS LOW-LEVEL MOISTURE INTO
LOOKING AHEAD:
LIFR CEILINGS ARE EXPECTED TO LIFT AND IMPROVE TO MVFR...PERHAPS
VFR...BETWEEN 12-18Z MONDAY AS A COLD FRONT APPROACHES THE MOUNTAINS
FROM THE WEST AND SOUTHWESTERLY WINDS STRENGTHEN TO 15-20 KT WITH
GUSTS UP TO 30 KT. A PERIOD OF MVFR CEILINGS AND SHOWER ACTIVITY
WILL BE POSSIBLE AS THE FRONT CROSSES THROUGH THE CAROLINAS MONDAY
NIGHT AND TUESDAY MORNING...WITH A POTENTIAL FOR A PROLONGED PERIOD
OF MVFR/IFR CEILINGS AT THE FAY/RWI TERMINALS TUESDAY INTO WEDNESDAY
AS THE FRONT TEMPORARILY STALLS NEAR OR JUST OFFSHORE THE CAROLINA
COAST. -VINCENT
&&
.CLIMATE...
DAILY RECORD HIGHS FOR MONDAY (DECEMBER 10):
RDU: 81 (2007)
GSO: 78 (2007)
FAY 79 (2007)
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...CBL/BLS
SHORT TERM...BADGETT
LONG TERM....BADGETT
AVIATION...VINCENT
CLIMATE...BADGETT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
237 AM EST SUN DEC 9 2012
.SYNOPSIS...
A WARM MOIST SOUTHERLY FLOW AHEAD OF AN APPROACHING COLD FRONT WILL
RESULT IN ABOVE NORMAL TEMPERATURES THROUGH MONDAY. THE COLD FRONT
WILL CROSS THE REGION MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 920 PM SATURDAY...
THE MAIN UPDATES TO THE FORECAST THIS EVENING WILL BE TO ADDRESS
CLOUD COVER AND RAPIDLY FALLING TEMPS. MID CLOUDS UPSTREAM EARLIER
THIS EVENING WERE MORE ROBUST AND EVENING PRODUCING SOME VERY LIGHT
PRECIP OVER SOUTHWESTERN NC...BUT HAVE SINCE DECREASED IN COVERAGE
AS THEY DRIFT SOUTHWEST TO NORTHEAST ACROSS THE AREA. IN AREAS
WHERE SKIES HAVE BEEN MOSTLY CLEAR...PARTICULARLY OVER THE EASTERN
HALF OF THE CWA...TEMPS HAVE QUICKLY FALLEN INTO THE UPPER 40S AND
LOWER 50S. THE LATEST RAP CONTINUES TO INDICATE MOISTURE UPSTREAM
INTO THE AREA WITH A PERIOD OF ISENTROPIC LIFT SUFFICIENT FOR
SCATTERED SHOWERS...MAINLY AROUND THE WESTERN PIEDMONT. DUE TO THE
EXPECTED INCREASE IN MID LEVEL CLOUD COVER...IN THE 4000-6000 FT
RANGE BASED ON UPSTREAM OBS AND FORECAST SOUNDINGS...THERE IS STILL
SOME UNCERTAINTY REGARDING THE COVERAGE OF FOG/STRATUS. WHERE SKIES
ARE CLEAR...VISIBILITIES HAVE FALLEN INTO THE 3 TO 6 MILE RANGE IN
SOME SPOTS...BUT NO FURTHER. WILL CONTINUE TO MONITOR THESE TRENDS
TO SEE IF A DENSE FOG ADVISORY IS NEED LATER TONIGHT....BUT CURRENT
THINKING IS THAT IT MAY BE MORE LIKELY OVER EASTERN AREAS.
WITH TEMPS APPROACHING FORECAST MINS IN SOME OUTLYING AREAS...ALSO
IN RESPONSE TO THE CLEAR SKIES...WILL LOWER MIN TEMPS A COUPLE
DEGREES. HOWEVER...IF CLOUDS MOVE IN AS EXPECTED...TEMPS SHOULD
BEGIN TO LEVEL OUT AND REMAIN IN THE UPPER 40S AND LOWER 50S. -BLS
AFTER THE MORNING LOW CLOUDS/FOG LIFT AND DISPERSE AND ISOLATED
SHOWER ACTIVITY EXITS THE AREA...A MIX OF SUN AND CLOUDS WILL
SUPPORT DAYTIME HIGHS IN THE MID TO UPPER 60S NORTH TO LOWER/MID 70S
SOUTH.
THE UPSTREAM TROUGH WILL BEGIN TO DIG INTO THE SOUTHERN PLAINS
SUNDAY NIGHT WITH ATTENDANT SFC COLD FRONT ADVANCING EAST INTO THE
TN VALLEY. RISING PWATS FROM STRENGTHENING WARM MOIST AIR
ADVECTION...INCREASING RIGHT-ENTRANCE REGION DYNAMICS...THE
POTENTIAL FOR WEAK INSTABILITY ALOFT ALONG WITH THE PROSPECTS OF
SOME WEAK SHORTWAVE DISTURBANCES TO MOVE THROUGH THE AREA IN THE
SWLY FLOW ALOFT WILL SUPPORT ISOLATED SHOWERS...MAINLY IN THE WEST
LATE SUNDAY NIGHT.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SATURDAY...
A COLD FRONT WILL APPROACH AND CROSS THE REGION OVERNIGHT MONDAY
INTO TUESDAY...ALTHOUGH THERE ARE STILL SOME TIMING DIFFERENCES
AMONG THE MODELS...BUT THERE CONTINUES TO SOME TREND OF A SLOWER
PASSAGE. AHEAD OF THE FRONT...INCREASING SOUTHWESTERLY WINDS WILL
USHER IN MOISTURE AND EVEN MORE WARMTH DURING THE DAY ON MONDAY.
TEMPS ARE EXPECTED TO RANGE FROM THE LOW 70S ACROSS THE NORTHWEST TO
THE MID 70S FURTHER SOUTH AND EAST. THERE COULD EVEN BE SOME UPPER
70S ACROSS THE SOUTHEAST...ALTHOUGH THE AMOUNT OF CLOUD COVER WILL
BE THE DETERMINING FACTOR AND AT THIS TIME...IT LOOKS LIKE THERE
WILL BE SUFFICIENT CLOUD COVER TO HOLD TEMPS DOWN SOME. HEATING MAY
ALSO BE TEMPERED SOME IN THIS REGION AS DEWPOINTS RISE INTO THE
LOWER 60S.
PRECIP CHANCES WILL INCREASE DURING THE DAY ON MONDAY AS WARM AIR
ADVECTION INCREASES ACROSS THE REGION...WITH SOME SPOTTY SHOWERS
POSSIBLE DURING THE DAY. THE BEST CHANCE OF PRECIP WILL COME
OVERNIGHT ON MONDAY AND INTO EARLY TUESDAY AS THE FRONT CROSSES THE
AREA. AS STATED ABOVE...THERE ARE SOME TIMING DIFFERENCES WITH
RESPECT TO THE SPEED OF THE FRONT...BUT WILL CONTINUE TO SHOW PRECIP
CHANCES TRENDING DOWNWARD LATE TUESDAY AFTERNOON/EVENING.
INSTABILITY APPEARS TO BE MARGINAL (AT BEST) AS THE FRONT CROSSES
THE AREA MONDAY NIGHT...BUT CANNOT COMPLETELY RULE OUT AN ISOLATED
THUNDERSTORM OR TWO.
TEMPS MONDAY NIGHT AND TUESDAY WILL ULTIMATELY BE DETERMINED BY THE
TIMING OF THE FRONT AND ASSOCIATED PRECIP AND EVENTUAL CAA. WITH THE
SLIGHTLY SLOWER FRONTAL TIMING...WILL SHOW MILD TEMPS MONDAY
NIGHT...GENERALLY IN THE 50S. HIGHS ON TUESDAY ARE EXPECTED TO BE IN
THE MID/UPPER 50S TO LOW/MID 60S AND MAY VERY WELL OCCUR IN THE
MORNING AND THEN FALL THROUGHOUT THE DAY. OVERNIGHT LOWS TUESDAY
NIGHT WILL LIKELY BE IN THE MID/UPPER 30S TO NEAR 40 DEGREES.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...
WEDNESDAY THROUGH THURSDAY...THEN THERE IS QUITE A BIT OF
UNCERTAINTY WITH RESPECT TO THE WEATHER FOR THIS TIME FRAME. BOTH
THE GFS AND ECMWF SHOW THE FRONT HANGING NEAR THE COAST WITH
MULTIPLE LOW PRESSURE WAVES TRACKING ALONG IT AND SPREADING PRECIP
INTO EASTERN NC...ALTHOUGH HOW FAR EAST IS IN QUESTION. THE GFS THEN
SHOWS A MID LEVEL KICKER WAVE MOVING INTO THE AREA WEDNESDAY WHICH
WOULD PUSH THE FRONT AND ASSOCIATED PRECIP OUT TO SEA. THE ECMWF IS
ALMOST 12-18 HOURS SLOWER WITH THIS MID LEVEL WAVE...HOWEVER THIS IS
SLIGHTLY FASTER THAN PREVIOUS RUNS OF THE ECMWF...SO THIS WILL HAVE
TO BE MONITORED. FOR NOW...WILL GO NO MORE THAN SLIGHT CHANCE POPS
FOR THIS TIME FRAME UNTIL MODELS COME INTO BETTER AGREEMENT AND WILL
JUST KEEP POPS CONFINED TO THE EASTERN PORTIONS OF THE FORECAST
AREA. TEMPS WILL LIKELY BE NEAR TO SLIGHTLY ABOVE NORMAL DURING THIS
TIME FRAME.
FRIDAY THOUGH SATURDAY...CONDITIONS THEN LOOK TO IMPROVE FOR THE END
OF THE WORK WEEK AS SURFACE HIGH PRESSURE AND MID LEVEL RIDGING
BUILD INTO THE AREA. MODELS THEN SHOW THE NEXT SYSTEM APPROACHING
THE REGION OVER THE WEEKEND...WITH CLOUDS AND PRECIP CHANCES
POSSIBLY BEGINNING TO INCREASE LATE SATURDAY (ALTHOUGH TIMING THIS
FAR OUT IS ALWAYS IN QUESTION). TEMPS WILL SLOWLY MODERATE AT THE
END OF THE WEEK AND ESPECIALLY INTO SATURDAY AS THE SURFACE HIGH
MOVES OFFSHORE AND SOUTHERLY FLOW RETURNS TO THE AREA.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 235 AM SUNDAY...
24-HR TAF PERIOD:
A FAIR AMOUNT OF UNCERTAINTY PERSISTS WITH REGARD TO HOW LOW
CEILINGS AND VISBYS WILL FALL THROUGH 12Z THIS MORNING. INCREASING
LOW AND MID-LEVEL CLOUD COVER SHOULD PREVENT VISBYS LOWER THAN
MVFR/IFR IN MOST LOCATIONS...EXCEPT PERHAPS AT THE RWI AND FAY
TERMINALS. REGARDLESS OF VISBYS...MVFR/IFR CEILINGS WILL BE POSSIBLE
AT THE RDU/INT/GSO TERMINALS BETWEEN 06-12Z...PRIMARILY AT INT/GSO
WHERE ELEVATED SHOWER ACTIVITY WILL BE POSSIBLE. EXPECT SUB-VFR FOG
OR CEILINGS TO LIFT AND IMPROVE BETWEEN 12-15Z...WITH VFR CONDITIONS
LIKELY IN MOST AREAS BY 15-18Z...EXCEPT PERHAPS AT THE INT/GSO
TERMINALS WHERE MVFR CEILINGS MAY PERSIST INTO THE AFTERNOON.
CEILINGS ARE EXPECTED TO DETERIORATE TO LIFR BETWEEN 03-12Z MONDAY
AS SOUTHWESTERLY FLOW ADVECTS LOW-LEVEL MOISTURE INTO
LOOKING AHEAD:
LIFR CEILINGS ARE EXPECTED TO LIFT AND IMPROVE TO MVFR...PERHAPS
VFR...BETWEEN 12-18Z MONDAY AS A COLD FRONT APPROACHES THE MOUNTAINS
FROM THE WEST AND SOUTHWESTERLY WINDS STRENGTHEN TO 15-20 KT WITH
GUSTS UP TO 30 KT. A PERIOD OF MVFR CEILINGS AND SHOWER ACTIVITY
WILL BE POSSIBLE AS THE FRONT CROSSES THROUGH THE CAROLINAS MONDAY
NIGHT AND TUESDAY MORNING...WITH A POTENTIAL FOR A PROLONGED PERIOD
OF MVFR/IFR CEILINGS AT THE FAY/RWI TERMINALS TUESDAY INTO WEDNESDAY
AS THE FRONT TEMPORARILY STALLS NEAR OR JUST OFFSHORE THE CAROLINA
COAST. -VINCENT
&&
.CLIMATE...
DAILY RECORD HIGHS FOR MONDAY (DECEMBER 10):
RDU: 81 (2007)
GSO: 78 (2007)
FAY 79 (2007)
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...CBL/BLS
SHORT TERM...KRR
LONG TERM....KRR
AVIATION...VINCENT
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1253 AM EST SUN DEC 9 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE GREAT LAKES IN THE WAKE OF A
DEPARTING COLD FRONT TONIGHT. THIS WILL GIVE A BRIEF RESPITE TO
THE RAINFALL UNTIL A WARM FRONT DEVELOPS OVER KENTUCKY EARLY
SUNDAY AND THEN LIFTS NORTHWARD. LOW PRESSURE WILL THEN TRACK
NORTHEAST THROUGH THE OHIO VALLEY AND ANOTHER COLD FRONT OVER THE
AREA WILL BE THE FOCUS FOR MORE RAINFALL SUNDAY NIGHT AND MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SHOWERS AND A FEW THUNDERSTORMS HAVE BEEN DEVELOPING ACROSS
KENTUCKY OVER THE PAST FEW HOURS WITH A WARM FRONT OVER THE AREA.
EXPECT THE SHOWERS TO REMAIN MAINLY ALONG AND SOUTH OF THE OHIO
RIVER INTO THE EARLY MORNING HOURS PER THE LATEST HRRR AND RAP13
RUNS...BUT THE RAIN WILL LIKELY BEGIN TO SPREAD FURTHER NORTH
TOWARDS DAYBREAK. BUMPED UP POPS A BIT TO ACCOUNT FOR THIS. REST
OF FORECAST LARGELY REMAINS ON TRACK WITH ONLY A FEW MINOR TWEAKS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
WARM FRONT OVER KENTUCKY LIFTS NORTH THROUGH OHIO DURING THE DAY
SUNDAY AND A SURFACE LOW TRACKS EAST ALONG IT AS IT DOES. THE
COMBINATION OF THE TWO WILL MEAN ANOTHER MILD DAY WITH AN EVER-
INCREASING CHANCE FOR SHOWERS.
ONCE THE LOW REACHES LAKE ERIE SUNDAY NIGHT...A COLD FRONT
ORIENTED ALONG THE I-71 CORRIDOR WILL BE A FOCUS FOR SHOWERS AND
EVEN SOME THUNDERSTORMS. RAIN AT TIMES COULD BE MODERATE IN
INTENSITY AND RIVERS AND STREAMS THAT MAY BE RUNNING HIGH WILL
NEED TO BE MONITORED A LITTLE CLOSER AS THE NEXT ROUND OF RAIN
COMES IN. THE MODERATE RAINFALL WILL PROBABLY OCCUR IN THE LATER
EVENING AS THE FLOW AT THE SURFACE AND ALOFT IS NEAR PARALLEL
SOUTHWEST TO NORTHEAST. THIS WILL TAP THE AVAILABLE GULF MOISTURE
WITH A STRONG TRANSPORT WIND OVER THE REGION UNTIL THE SURFACE
GRADUALLY SHOWS AND EASTWARD PROGRESSION ON MONDAY IN RESPONSE TO
THE COLDER AIR BEING USHERED IN ON NORTHWEST WINDS.
A LARGE PORTION OF THE ATMOSPHERE WILL SEE QUITE A BIT OF
SLANTWISE CONVECTION AND THE THREAT FOR THUNDER IN THESE SHOWERS
IS HIGHER THAN AVERAGE...THOUGH THE SEVERE THREAT INHERENT WITH
THUNDERSTORMS WILL BE QUITE MINIMAL IF IT DOES EXIST AT ALL. I
TOOK NAM CAPE VALUES OVER 30 TO INDICATE THE THREAT FOR THUNDER.
WITH REGARDS TO THE HEAVIER RAIN...THIS STARTED SUNDAY EVENING AND
RAN THROUGH MONDAY EVENING WHERE POPS LIKELY OR HIGHER WERE BEING
FORECAST. THE RAIN WILL TURN OFF NORTHWEST TO SOUTHEAST ON MONDAY
WITH VERY LITTLE ACTIVITY SLATED TO REMAIN MONDAY NIGHT. THE
DEEPER COLD AIR IS WELL BEHIND THE RAINFALL SO I HAVE REMOVED
MENTION OF ANY SNOW.
TEMPERATURES WERE ONLY MINORLY ADJUSTED AND ARE SHOWING A PRETTY
GOOD CONSISTENCY BETWEEN GUIDANCE VALUES AND THE PREVIOUS
FORECAST.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS THE PERIOD BEGINS...THE MODELS ARE SHOWING SFC HIGH PRESSURE
BEGINNING TO PUSH INTO THE REGION. THE HIGH STRENGTHENS IT GRIP OVER
THE REGION DURING THE DAY TUESDAY. THE CENTER OF THE HIGH WILL
STRETCH OVER THE UPPER OHIO VALLEY BY DAYBREAK ON WEDNESDAY AND HIGH
PRESSURE WILL CONTROL THE REGIONS WEATHER INTO FRIDAY.
RIGHT NOW MODELS ARE IN GOOD AGREEMENT IN FORMING A SFC LOW IN THE
PLAINS ON FRIDAY AND EJECTING IT OUT INTO THE WESTERN LAKES BY
SATURDAY. FA WILL ONCE AGAIN BE ON THE WARM SIDE OF THE SYSTEM...SO
IT LOOKS LIKE A ANOTHER SHOT OF RAIN FOR NEXT SATURDAY.
TUESDAY SHOULD BE THE COLDEST DAY OF THE WEEK WITH CAA BEHIND THE
DEPARTING SYSTEM. HIGH WILL ONLY BE IN THE MID 30S TO AROUND 40.
MOSTLY CLEAR SKIES TUESDAY WITH THE BUILDING HIGH SHOULD ALLOW
TEMPERATURES TO FALL BACK INTO THE LOWER TO MID 20S. A GRADUAL WARM
UP THEN BEGINS ON WEDNESDAY AS HIGH ARE EXPECTED TO PUSH INTO THE
LOWER TO MID 40S. HIGHS WILL PUSH INTO THE UPPER 40S TO LOWER 50S BY
THE END OF THE WEEK.
ANOTHER COOL NIGHT IS EXPECTED WEDNESDAY NIGHT WITH TEMPERATURES
FALLING BACK INTO THE 20S BEFORE THE WARMER AIR BEGINS TO WORK IN
AHEAD OF THE DEVELOPING SYSTEM BY THE END OF THE PERIOD.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
REMAINING MVFR CIGS WILL GRADUALLY LOWER TO IFR THIS MORNING AS A
WARM FRONT TO OUR SOUTH BEGINS TO LIFT NORTHWARD ACROSS THE AREA.
SHOWERS ALONG THIS FRONT SHOULD REMAIN CONFINED TO THE SOUTHERN
TERMINALS THIS MORNING. AREAS OF MVFR MIST WILL BE LIKELY ACROSS
THE KDAY/KILN THROUGHOUT TONIGHT. AS THE WARM FRONT LIFTS NORTH OF
THE TERMINALS DURING THE LATE MORNING...CIGS SHOULD RAISE BACK TO
MVFR. THE WARM FRONT MAY NOT MAKE IT AS FAR AS KDAY...SO KEPT IFR
CIGS IN THEIR FORECAST THROUGHOUT THE DAY. BY LATE THIS
AFTERNOON...SHOWERS AND POSSIBLY IFR CIGS WILL SPREAD ACROSS ALL
TERMINALS AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM. THERE MAY BE
ENOUGH INSTABILITY ACROSS THE SOUTHERN TERMINALS LATE THIS
AFTERNOON TO PRODUCE SOME THUNDER AS WELL. PRECIPITATION IS
EXPECTED TO AFFECT ALL TERMINALS THEREAFTER THROUGH THE END OF THE
TAF PERIOD.
OUTLOOK...IFR CEILINGS AND MVFR VISIBILITIES LIKELY LATE SUNDAY
NIGHT WITH IMPROVEMENT TO MVFR CEILINGS ON MONDAY. MVFR CEILINGS
MAY LINGER INTO MONDAY NIGHT AND TUESDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...KURZ
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
455 AM EST SUN DEC 9 2012
.SYNOPSIS...
A COLD FRONT FROM NEW ENGLAND TO THE TENNESSEE VALLEY WILL MOVE
SLOWLY SOUTHEAST TODAY BEFORE STALLING AND PUSHING BACK NORTH AS
WARM FRONT TONIGHT. A MUCH STRONGER COLD FRONT WILL CROSS THROUGH
THE AREA FROM THE WEST MONDAY EVENING. COOL HIGH PRESSURE WILL BUILD
IN BEHIND THE FRONT FOR TUESDAY INTO FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 430 AM EST SATURDAY...
SCATTERED TO NUMEROUS SHOWERS...ASSOCIATED WITH A SHORT WAVE
MOVING THROUGH WEST VIRGINIA...WERE TRACKING NORTHEAST ACROSS THE
WESTERN COUNTY WARNING AREA EARLY THIS MORNING. WATER VAPOR LOOP
SHOWED ANOTHER SHORT WAVE JUST ENTERING WESTERN KENTUCKY AND
TENNESSEE WHICH MODELS TAKE ALONG THE SAME TRACK. THIS SHOULD
BRING MORE SHOWERS TO THE WESTERN COUNTY WARNING AREA THIS
AFTERNOON.
SCATTERED SHOWERS WERE ALSO MOVING THROUGH SOUTHSIDE VIRGINIA.
ONCE THESE SHOWERS MOVE THROUGH THIS MORNING THE CHANCE OF
PRECIPITATION WILL BE LOWER IN THIS PART OF THE FORECAST AREA FOR
THE REST OF THE DAY.
THE COLD FRONT EXTENDED FRONT NEW JERSEY TO CENTRAL KENTUCKY.
ONCE THE WEST VIRGINIA SHORT WAVE MOVES SLIGHTLY FARTHER
NORTH...THE FRONT WILL ADVANCE SOUTH INTO THE FOOTHILLS THIS
MORNING. LOCAL WRK AND LATEST RAP SHOWED THE WEDGE REACHING THE
ROANOKE RIVER BY THE END OF THE DAY BEFORE ADVANCING SLOWLY BACK
NORTH TONIGHT.
HAVE MORE CLOUD COVER AND COOLER TEMPERATURES NORTH OF THE FRONT
TODAY AND MORE FOG OVERNIGHT TONIGHT. USED A NON DIURNAL TREND FOR
HOURLY TEMPERATURES OVERNIGHT. THOSE LOCATIONS THAT PULL OUT OF
THE WEDGE WILL LIKELY WARM UP AS THEY GET BACK INTO THE WARM
SECTOR.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 330 AM EST SUNDAY...
PRIMARY FOCUS FOR THE SHORT TERM FORECAST WAS ON THE TIMING OF THE
COLD FRONT MOVING THROUGH THE FORECAST AREA LATE MONDAY AND MONDAY
NIGHT. WITH SFC WAVES RIDING UP THE SFC BOUNDARY AND
INITIAL UPPER LEVEL SHORTWAVE LIFTING NORTH WITH MORE
ENERGY DIGGING INTO THE BASE OF THE UPPER LEVEL TROF IN THE CENTRAL
U.S....CONTINUED TO LEAN TOWARD THE SLOWER MODEL SOLUTIONS.
FOR THIS FORECAST PACKAGE...THE SLOWER NAM AND SREF WERE
PREFERRED.
AS WINDS VEER IN RESPONSE TO THE APPROACH OF THE UPPER LEVEL
TROF...SFC WEDGE SHOULD HAVE ERODED BY 12Z MONDAY...OR SHORTLY
THEREAFTER...LEAVING THE ENTIRE FORECAST FIRMLY ENTRENCHED IN THE
WARM SECTOR. A DEEP SOUTHWEST FLOW ALONG WITH SOME BREAKS IN THE
CLOUDS IN THE EAST SHOULD ALLOW TEMPS TO SOAR WELL ABOVE
NORMAL...BUT STILL BELOW RECORDS FOR 12/10.
BEST 850-300MB OMEGA PER THE NAM ARRIVES IN THE WEST AROUND 18Z
MONDAY...BUT LIFTS TO THE NORTH AFTERWARDS WITH UPPER LEVEL
SHORTWAVE. THIS LEAVES UNCERTAINTY ON HOW FAR EAST PRECIPITATION
SHIELD CAN TRAVEL. AS A RESULT...KEPT MUCH HIGHER POPS IN THE
MOUNTAINS...WITH HIGH CHANCE POPS IN THE EAST LATE MONDAY AND MONDAY
NIGHT.
NAM FORECAST SOUNDINGS INDICATE THE LOWER LEVEL OF THE ATMOSPHERE
BEGINS DRYING WHEN TEMPS COLD ENOUGH FOR SNOW BEGINS TO ARRIVE
ALONG THE WESTERN SLOPES. MAY STILL BE ABLE TO SQUEEZE OUT SOME
LIGHT SNOW SHOWERS IN THE HIGHEST ELEVATIONS OF SOUTHEAST
WV/ALLEGHANY HIGHS FOR A FEW HOURS TUESDAY MORNING.
EVEN THE SLOWEST SREF KEEPS SFC BOUNDARY WELL SOUTHEAST OF THE
FORECAST AREA ON TUESDAY. WEAK SFC WAVES MOVING THROUGH EASTERN
NC/VA ON TUESDAY WILL KEEP SOME CLOUDS IN THE FAR EAST...BUT LOW
LEVEL NORTHWEST WINDS WILL KEEP THE FORECAST AREA DRY BY 18Z.
AS SFC RIDGE QUICKLY BUILDS OVER THE AREA TUESDAY...COLD AIR
ADVECTION DIMINISHES DURING THE DAY AND EXPECT TEMPS TO RECOVER AND
USED A BLEND OF THE NAM/GFS MOS GUIDANCE FOR HIGHS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 330 PM EST SATURDAY...
HIGH PRESSURE WILL CONTROL THE WEATHER PATTERN THROUGH FRIDAY. WILL
BE KEEPING AN EYE ON A LOW PRESSURE SYSTEM DEVELOPING ALONG THE
CAROLINA COAST OF WEDNESDAY/THURSDAY TO SEE IF ANY SHOWER ACTIVITY
ADVANCES INTO THE PIEDMONTS...BUT BECOMING MORE CONFIDENT THAT THIS
ACTIVITY WILL STAY EAST OF THE AREA. THE NEXT BIG STORM SYSTEM TO
WATCH WILL ARRIVE NEXT WEEKEND AS A DEEP LOW PRESSURE SYSTEM PASSES
EASTWARD FROM THE CENTRAL PLAINS INTO THE GREAT LAKES...DRAGGING A
COLD FRONT TOWARD OUR AREA.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
AS OF 1115 PM EST SATURDAY...
BROKEN BAND OF SHOWERS WILL CONTINUE TO AFFECT KLWB AND PERHAPS
KBLF OVERNIGHT WITH A SLOW DOWNTURN TO MVFR THERE WITH MAINLY VFR
PREVAILING ELSW BEFORE FOG DEVELOPS SHORTLY AFTER MIDNIGHT.
MOISTURE WILL THEN DEEPEN TOWARD DAWN SUNDAY AS A COLD FRONT TO
THE NW BACKDOORS SOUTH DOWN EAST OF THE MOUNTAINS BY MORNING. THIS
SHOULD AID LIFT SOME ESPCLY AFTER MIDNIGHT WITH CIGS LOWERING TO
MVFR MOST SPOTS THEN DROPPING TO IFR OR WORSE IN STRATUS/FOG
ESPCLY KROA AND POINTS EAST DURING THE EARLY MORNING HOURS OF
SUNDAY. HOWEVER IF SKIES STAY CLEAR LONGER OVERNIGHT THEN COULD
ALSO SEE POOR FLYING CONDITIONS DEVELOP SOONER DUE TO FOG AND
STRATUS FORMATION. OTRW EARLIER CLOUD COVER MAY LIMIT LOWER CIGS
ACROSS THE SE WVA SITES EXCEPT AT KLWB WHERE RAINFALL SHOULD AID
FOG FORMATION AND POSSIBLY A PERIOD OF IFR BY DAYBREAK.
THE IFR TO MVFR CEILINGS...IN CONJUNCTION WITH THE WEDGE OUT EAST
WILL LIKELY BE SLOW TO EXIT SUNDAY MORNING ESPCLY IF DRIZZLE
DEVELOPS AND HELPS HOLD LOWER CIGS IN LONGER. ALSO POTENTIAL FOR
LIFT TO RESULT IN CONTINUED SCATTERED SHRA ACROSS THE WEST INTO
SUNDAY AFTERNOON SO LEFT IN MENTION FROM KBCB WESTWARD. CONDITIONS
MAY IMPROVE SLIGHTLY BY SUNDAY AFTERNOON TO MVFR OR EVEN VFR
ESPCLY WEST OF THE BLUE RIDGE WITH ONLY A GRADUAL LIFTING OF
CIGS/VSBYS FROM SOUTH TO NORTH EAST OF THE BLUE RIDGE. MAY EVEN
SEE KLYH/KROA STAY MVFR OR WORSE AT TIMES UNTIL LATE SUNDAY. AGAIN
EXPECT MORE FOG AND LOW CLOUDS TO REDEVELOP ESPCLY EAST SUNDAY
NIGHT BEFORE THINGS PERHAPS SCOUR OUT TO HIGH END MVFR OR VFR
MONDAY MORNING. THEN A STRONGER COLD FRONT PUSHES THROUGH FROM
WEST MONDAY NIGHT...BRINGING MVFR TO IFR CONDITIONS ONCE AGAIN
WITH POSSIBLY HEAVIER SHOWERS. NORTHWEST CROSS BARRIER WINDS
BEHIND THE COLD FRONT WILL LIKELY RESULT IN STRONG MECHANICAL
TURBULENCE FOR MONDAY NIGHT AND TUESDAY.
CONDITIONS WILL IMPROVE ON TUESDAY EVENING AS HIGH PRESSURE
BEGINS TO SETTLE ACROSS THE AREA. LINGERING MOISTURE IN THE
MOUNTAINS TUESDAY WILL RESULT IN MVFR CONDITIONS AND THE
POSSIBILITY OF SNOW SHOWERS AS COLDER AIR SURGES INTO THE AREA.
VFR SHOULD MAKE A GRADUAL RETURN BY TUESDAY NIGHT INTO WEDNESDAY
AND THEN LINGER THRU LATE NEXT WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...PH
LONG TERM...NF
AVIATION...AMS/JH/SK
AREA FORECAST DISCUSSION
NWS WICHITA KS
527 AM CST SUN DEC 9 2012
.AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
THE MAIN AVIATION FORECAST CONCERN IS LIFR/IFR CONDITIONS AHEAD OF
THE FRONT AND THEN STRONG GUSTY WINDS BEHIND THE FRONT TODAY.
THE COLD FRONT IS THROUGH MUCH OF KANSAS...BUT THE STRONGER WINDS
ARE JUST REACHING KRSL AS OF 11Z. WINDS WILL ONLY CONTINUE TO GET
STRONGER THROUGHOUT THE DAY WITH 20-25 KTS GUSTING TO 30-35
EXPECTED ACROSS ALL TERMINALS TODAY. WINDS WILL DECREASE
SOME...BUT STAY BREEZY OVERNIGHT.
AHEAD OF THE FRONT LIFR AND IFR CONDITIONS DOMINATE UNDER LOW
STRATUS. AS THE DRIER/COOLER AIR MOVES IN BEHIND THE FRONT...LOW
STRATUS IS SCATTERING OUT WITH A MID LEVEL CLOUD DECK OVERHEAD.
HAVE REMAINED PESSIMISTIC WITH THE FORECAST AT SITES THAT ARE
AHEAD OF THE FRONT...KICT/KCNU KEEPING THEM IN LIFR UNTIL THE
EXPECTED FRONTAL PASSAGE...ALTHOUGH IT MAY BE OFF AND ON WITH
RAGGED CEILINGS ACROSS THE AREA. SKIES WILL BEGIN TO CLEAR
OVERNIGHT FROM KRSL TO KICT UNDER HIGH PRESSURE.
WHILE THERE IS STILL A HINT OF SOME PRECIPITATION WITH THIS
SYSTEM...CONFIDENCE IS LOW THAT ANY WILL ACTUALLY REACH THE
GROUND. THERE IS DECENT LIFT IN THE MID-LEVELS...BUT THE LOWEST
8-12 KFT ARE VERY DRY AND WOULD EXPECT ANY PRECIPITATION THAT DOES
FALL TO EVAPORATE. THAT BEING SAID...CANNOT RULE OUT SOME DRIZZLE
AHEAD OF THE FRONT...AND SOME FLURRIES BEHIND THE FRONT. DID LEAVE
MENTION OF FLURRIES OUT OF THE FORECAST AT ALL TERMINALS BECAUSE
OF THIS. ANY ACTIVITY THAT DOES OCCUR WILL NOT REDUCE
VISIBILITIES.
BILLINGS
&&
.PREV DISCUSSION... /ISSUED 329 AM CST SUN DEC 9 2012/
DISCUSSION...
TODAY-THIS EVENING:
THE GUSTY NORTHWEST WINDS AND COLDEST AIR IS LAGGING BEHIND THE
INITIAL WIND SHIFT. PRECIPITATION SO FAR HAS BEEN EXTREMELY LIMITED
AND BASED ON LATEST MODEL RUNS...LOW LEVEL DRY AIR WILL LIKELY BE
TOUGH TO OVERCOME. HOWEVER BEST SATURATION/LIFT IN TRAILING BAND
FAIRLY IMPRESSIVE...BUT SO IS THE 10KFT OF DRY AIR BELOW IT. WHILE
LIGHT SNOW IS LIKELY ALOFT...BELIEVE IT WILL BE VERY DIFFICULT TO
GET MORE THAN SCATTERED FLURRIES TO THE GROUND. MID/UPPER LEVEL LIFT
ACTUALLY INCREASES A BIT TOWARDS 0000 UTC...AND WILL LINGER
FLURRIES UNTIL MIDNIGHT ACROSS EASTERN SECTIONS. TEMPERATURES WILL
GENERALLY FALL THROUGHOUT THE DAY WITH COLD AIR ADVECTION FROM THE
GUSTY NORTHWEST WINDS.
LATE TONIGHT:
TEMPERATURES WILL CONTINUE TO TUMBLE DURING THE NIGHT WITH CLEARING
SKIES AND DECREASING WINDS. MODEL OUTPUT STATISTICS GUIDANCE IN
GOOD AGREEMENT FOR SINGLE DIGITS FOR FAR NORTHWEST SECTIONS.
MON-SAT:
AFTER VERY CHILLY START TO MONDAY...EXPECT A GRADUAL MODERATION OF
THE COLD AIRMASS. SHORTWAVE MOVING THROUGH MIDWEEK STILL APPEARS TO
BE MOISTURE STARVED WITH ONLY SOME INCREASE IN CLOUDS. DECENT
WARMUP ANTICIPATED WITH COMBINATION OF DRY AIR AND FAVORABLE SW
FLOW AT H85 ON THU. MODELS HAVE DIVERGED WITH TRACK/TIMING OF
SYSTEM LATE IN THE WEEK. UNFORTUNATELY...OVERALL TREND HAS LOWER
CHANCES FOR PRECIPITATION ACROSS WESTERN HALF OF FORECAST AREA AS
SURFACE CYCLOGENSIS DEVELOPS DRY SLOT OVER MUCH OF THE FORECAST
AREA. BEST CHANCE STILL APPEARS TO BE IN SOUTHEAST KS. -HOWERTON
AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
LOW LEVEL ISENTROPIC LIFT FROM THE SOUTH-SOUTHWEST HAS LED TO
WIDESPREAD IFR CONDITIONS ACROSS THE REGION LATE THIS EVENING. BOTH
THE NAM/WRF AND GFS NOT HANDLING THIS LOW LEVEL MOISTURE VERY
WELL...WITH THE LATEST RUC40 CLOSER TO REALITY. THE CEILINGS EVEN
DROPPED LOWER THAN THE PESSIMISTIC RUC ON CEILINGS TO AROUND 6-9K FT
AGL.
EXPECT THE IFR CONDITIONS TO BE SHORT LIVED...AS A COLD FRONTAL
BOUNDARY LOOKS TO ARRIVE AFTER 08Z-09/SUN ACROSS CENTRAL
KANSAS...AND PLUNGE SOUTH ACROSS SOUTH CENTRAL KS AFTER 09-11Z/SUN.
THIS WILL LEAD TO CEILINGS BEGINNING TO RAPIDLY LIFT WITH MVFR/VFR
CEILINGS RETURNING BY THE MORNING HOURS ON SUN...AS LOW LEVELS
QUICKLY DRY OUT. WINDS BEHIND THE FRONT WILL INCREASE TO 20-30 KTS
WITH SOME LIGHT SNOW DEVELOPING ACROSS PORTIONS OF CENTRAL KANSAS
EARLY SUNDAY. NOT EXPECTING THE LIGHT SNOW TO RESTRICT VSBYS MUCH
WITH VFR CONDITIONS EXPECTED...AS THIS WILL BE MAINLY A LIGHT
SNOW/FLURRY EVENT.
KETCHAM
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 38 13 37 19 / 10 10 0 0
HUTCHINSON 35 11 37 21 / 10 10 0 0
NEWTON 35 12 35 20 / 10 10 0 0
ELDORADO 38 13 35 18 / 10 10 0 0
WINFIELD-KWLD 41 14 37 21 / 10 10 0 0
RUSSELL 33 4 37 19 / 10 0 0 0
GREAT BEND 33 7 37 22 / 20 0 0 0
SALINA 35 10 37 20 / 10 10 0 0
MCPHERSON 34 11 37 20 / 10 10 0 0
COFFEYVILLE 46 20 36 19 / 20 10 0 0
CHANUTE 43 16 34 18 / 20 10 0 0
IOLA 42 16 34 20 / 20 10 0 0
PARSONS-KPPF 44 17 35 16 / 20 10 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1044 AM EST SUN DEC 9 2012
.SYNOPSIS...
A SURFACE LOW WILL PUSH NORTHEAST INTO THE OHIO VALLEY TODAY AND
LIFT A WARM FRONT IN THE REGION. THIS WILL ALLOW FOR SHOWERS TO
RETURN TO THE AREA AND CONTINUE INTO MONDAY. A COLD FRONT WILL
CROSS THE AREA ON MONDAY...ALLOWING FOR A CHANGE OVER TO SNOW
SHOWERS MONDAY NIGHT WITH A MUCH COOLER AIR MASS BUILDING INTO THE
AREA FOR THE MID-WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
15Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ADJUST
POPS TODAY TO ACCOUNT FOR THE NEXT WAVE OF SHOWERS. IN
ADDITION...THUNDER MENTION HAS BEEN ADDED FOR THIS AFTERNOON INTO
EARLY TONIGHT FOR LOCATIONS SOUTH AND WEST OF PITTSBURGH.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A SHORT WAVE TROUGH
MOVING FROM THE NORTHERN PLAINS INTO THE UPPER MIDWEST WITH THE
UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW WELL AHEAD OF THIS
FEATURE. AT THE SURFACE...THERE ARE TWO LOWS WELL UPSTREAM...ONE
MOVING INTO THE UPPER MIDWEST AND ANOTHER INTO THE MISSOURI
VALLEY. THE FRONTAL BOUNDARY BETWEEN THESE TWO LOWS IS THE DEMARCATION
BETWEEN A WARM AND MOIST AIR MASS AHEAD AND ARCTIC AIR BUILDING IN
BEHIND IT. A WARM FRONT EXTENDS NORTHEASTWARD FROM THE SOUTHERN
LOW ACROSS KENTUCKY AND INTO SOUTHERN WV. LOCALLY...THE FIRST
SHORT WAVE IS SHIFTING EAST OF THE RIDGES WHILE THE NEXT WAVE IS
RIDING ALONG AND NORTH OF THE WARM FRONT AND DEVELOPING ACROSS
EASTERN KENTUCKY.
THIS AFTERNOON...THE SURFACE LOW ACROSS THE MISSOURI VALLEY WILL
QUICKLY LIFT INTO THE OHIO VALLEY...MERGING WITH THE LOW IN THE UPPER
MIDWEST AND PULLING THE WARM FRONT NORTHWARD INTO THE UPPER OHIO
VALLEY. THE AREA OF SHOWERS AND EMBEDDED ISOLATED THUNDERSTORMS
ASSOCIATED WITH THE SHORT WAVE IN KENTUCKY WILL SLIDE
NORTHEASTWARD WITH THE WARM FRONT INTO THE UPPER OHIO VALLEY EARLY
THIS AFTERNOON. MESOSCALE MODELS ARE SUPPORTIVE OF THIS FEATURE
MOVING THROUGH PART OF THE AREA BY LATE EVENING...AND THUS POPS
INCREASE TO CATEGORICAL BY 00Z.
RAP/NAM MODEL SOUNDINGS AT KZZV INDICATE SOME NARROW CAPE
DEVELOPING (LESS THAN 200 J/KG) AFTER 21Z. WITH THE WARM FRONT
LIFTING INTO THE AREA AND TDS SURGING INTO THE LOWER TO MID
50S...HAVE ADDED THE SCHC OF THUNDER THIS AFTERNOON INTO THE
EVENING FOR LOCATIONS SOUTH AND WEST OF PITTSBURGH.
TEMPS TODAY WILL SUBJECT TO THE NORTHWARD PROGRESSION OF THE WARM
FRONT. LAMP/WRF-NMM SUGGEST TEMPS WILL BE SLOW TO WARM MUCH OF THE
DAY WITH THE WARM SURGE OCCURRING AND HIGH TEMPS OCCURRING AFTER
21Z. THUS...WITH THE FRONT PUSHING INTO THE AREA...QUITE A THERMAL
GRADIENT CAN BE EXPECTED FOR HIGHS TODAY THAT WILL RANGE FROM THE
LOWER 40S IN JEFFERSON/FOREST COUNTIES TO THE LOWER 60S IN
PORTIONS OF NORTH-CENTRAL WV AND EASTERN OHIO.
TONIGHT...THE MERGED SURFACE LOW WILL CROSS THE OHIO VALLEY AND PUSH
INTO THE EASTERN GREAT LAKES. THE WARM FRONT WILL SHIFT NORTHEAST
OF THE AREA AND A COLD FRONT AND ITS ASSOCIATED SURFACE TROUGH WILL
BEGIN TO APPROACH FROM THE WEST. BETWEEN WARM FRONTAL SHOWERS AND
SCHC THUNDER INITIALLY AND SHOWERS AHEAD OF THE COLD FRONT MOVING
IN FROM THE WEST...CATEGORICAL POPS ARE FORECAST THROUGH MUCH OF
THE OVERNIGHT. TEMPS WILL DROP OFF LITTLE OVERNIGHT IN WAA...WITH
LOWS RANGING FROM THE MID 50S IN NORTH-CENTRAL WV TO THE MID 40S
ALONG THE I-80 CORRIDOR.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
THE SURFACE TROUGH AND COLD FRONT WILL CROSS THE AREA THROUGH THE
EARLY PART OF THE DAY...WITH CATEGORICAL POPS. TEMPERATURES WILL
REMAIN MILD WITH VALUES MAINLY IN THE UPPER 40S TO MID 50S INTO
MIDDAY MONDAY. STRONG CAA WILL THEN BEGIN BEHIND THE FRONT...AS
THE AFOREMENTIONED ARCTIC AIR MASS BEGINS TO PUSH IN FROM THE
WEST. BEFORE RAIN COMES TO AN END OR CHANGES TO SNOW...CONCUR WITH
HPC THAT RAINFALL AMOUNTS FOR SUNDAY INTO MONDAY WILL BE ON THE
ORDER OF 1.0 TO 1.3 INCHES.
CONSEQUENTLY REMAINING POSTFRONTAL SHOWERS MONDAY NIGHT WILL TURN
TO SNOW SHOWERS LATE. THE POSTFRONTAL COLD POOL WILL REMAIN
ACROSS THE UPPER OHIO VALLEY INTO WEDNESDAY...KEEPING SKIES MAINLY
CLOUDY. HOWEVER CONDITIONS TUESDAY INTO WEDNESDAY SHOULD BE DRY AS
INCOMING HIGH PRESSURE SUBSIDENCE AND LOW LEVEL WESTERLY WINDS
WILL MITIGATE CHANCES OF LAKE EFFECT SNOW SHOWER DEVELOPMENT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS ECMWF AND CANADIAN MODEL OUTPUT CONCUR THAT NEARBY HIGH
PRESSURE WILL PROMOTE DRY CONDITIONS WEDNESDAY NIGHT INTO FRIDAY.
ECMWF AND GFS AGREE THAT A CLOSED MID-LEVEL LOW WILL DEVELOP
ACROSS THE CENTRAL PLAINS ON FRIDAY NIGHT AND SHIFT INTO THE GREAT
LAKES REGION BY SATURDAY. AHEAD OF THIS FEATURE...CHANCE POPS
RETURN TO THE AREA. MODEL PREDICTABILITY A WEEK OUT MAKES IT
DIFFICULT TO PIN DOWN SPECIFICS IN FRONTAL PLACEMENT...HOWEVER
THIS PATTERN FAVORS THE POTENTIAL FOR OVERRUNNING ALONG WITH WARM
FRONTAL RAIN SHOWERS WELL AHEAD OF THE LOW.
TEMPERATURES WILL REBOUND TO WARMER THAN NORMAL THIS PERIOD WITH
VALUES FRIDAY AND SATURDAY ANYWHERE FROM 5 TO 10 DEGREES ABOVE
NORMAL.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
LOWER CLOUDS HAVE DEPARTED ACROSS THE NORTHERN TERMINALS AT LEAST
FOR A TIME WITH VFR MID DECKS AT KFKL AND KDUJ. ELSEWHERE IFR AT
TIMES CONTINUES AT KMGW WHILE LOW MVFR REMAINS ELSEWHERE.
WARM FRONT EXPECTED TO PUSH NORTH LATER THIS AFTERNOON AND SHOULD
BRING CIGS DOWN AS THE AFTERNOON PROGRESSES WITH RAIN DEVELOPING AT
ALL SITES. CIGS WILL LOWER TO IFR AFTER A FEW HOURS OF RAIN THIS
EVENING.
WINDS WILL BE GENERALLY FROM THE EAST NEAR 10 KTS. UNTIL FRONT
PUSHES NORTH LATER TONIGHT WHEN SOUTH WINDS AT SIMILAR SPEEDS
EXPECTED.
.OUTLOOK.../MONDAY THROUGH THURSDAY/...
MVFR AND PSBL IFR RESTRICTIONS WL CONTINUE WITH RAIN MONDAY AS A
COLD FRONT MOVES THROUGH. MVFR CONDITIONS ARE EXPECTED MONDAY NIGHT
INTO TUESDAY. LINGERING RAIN SHOWERS MAY CHANGE TO SCATTERED SNOW
SHOWERS BEFORE ENDING EARLY TUESDAY. HIGH PRES AND VFR CONDS ARE
EXPECTED LATER TUESDAY THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
AVIATION...RSMITH
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
611 AM EST SUN DEC 9 2012
.SYNOPSIS...
LOW PRESSURE COMING NORTHEAST FROM MISSOURI WILL BRING THE UPPER
OHIO VALLEY MILD TEMPERATURES AND BOUTS OF RAIN INTO MONDAY...
FOLLOWED BY A COOL DOWN TO SEASONABLE TEMPERATURES TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BASED OF BLEND OF RECENT SREF MODEL OUTPUT...WITH DETAILS FROM
RECENT RAP WRF-NMM AND NAM MODEL RUNS...SHOW A LOW PRESSURE
SYSTEM WILL BE MOVING FROM MISSOURI THIS MORNING TO OHIO THIS
EVENING. WARM FRONT CONVERGENCE ENHANCED BY JETSTREAM DYNAMICS
ALOFT WILL SPAWN A SURGE OF RAIN TO SPREAD NORTHWARD ACROSS THE UPPER
OHIO TODAY. LOCATIONS SOUTH OF THE I-70 CORRIDOR CAN EXPECT BOUTS
OF RAIN STARTING THIS MORNING...WHILE LOCATIONS FARTHER NORTH MAY
NOT GET MUCH RAIN UNTIL AFTERNOON.
HAVE ADDED MENTION OF DENSE FOG ACROSS THE HIGHER ELEVATIONS OF
TUCKER COUNTY WV AND GARRETT COUNTY MD...BASED ON RECENT SURFACE
DATA. FOG SHOULD CONTINUE INTO MID MORNING WHEN FIRST BOUT OF RAIN
LESSENS.
TEMPERATURES WILL CONTINUE TO BE MILD WITH HIGHS THIS AFTERNOON
ABOUT 15 DEGREES WARMER THAN NORMAL...PER BLEND OF GFS AND NAM
MOS AND RAP AND GFS LAMP HOURLY VALUES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
RECENT SREF MODEL OUTPUT SHOWS A NORTHEAST SURGE OF MODERATE RAIN
ACROSS THE UPPER OHIO TONIGHT AND MONDAY...UNTIL THE LOW PRESSURE
CENTER PASSES NORTHEAST TO NEW YORK STATE MONDAY AFTERNOON. CONCUR
WITH HPC THAT RAIN AMOUNTS FOR THIS EVENT CAN BE ON THE ORDER OF
1.0 TO 1.3 INCHES.
TEMPERATURES WILL REMAIN MILD WITH VALUES MAINLY IN THE UPPER 40S
TO MID 50S INTO MIDDAY MONDAY. ONCE THE LOW PRESSURE CENTER EXITS
NORTHEAST...A COLD FRONTAL PASSAGE WILL ENSUE MONDAY
AFTERNOON. THE COOL DOWN CAN BEGIN MONDAY AFTERNOON WITH VALUES
LATE MONDAY NIGHT INTO WEDNESDAY NEAR OR SLIGHTLY COLDER THAN
NORMAL.
CONSEQUENTLY REMAINING POSTFRONTAL SHOWERS MONDAY NIGHT CAN TURN
TO SNOW SHOWERS LATE. THE POSTFRONTAL COLD POOL CAN REMAIN ACROSS
THE UPPER OHIO VALLEY INTO WEDNESDAY...KEEPING SKIES MAINLY
CLOUDY. HOWEVER CONDITIONS TUESDAY INTO WEDNESDAY SHOULD BE DRY AS
INCOMING HIGH PRESSURE SUBSIDENCE AND LOW LEVEL WESTERLY WINDS
WILL MITIGATE CHANCES OF LAKE EFFECT SNOW SHOWER DEVELOPMENT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS ECMWF AND CANADIAN MODEL OUTPUT CONCUR THAT NEARBY HIGH
PRESSURE WILL PROMOTE DRY CONDITIONS WEDNESDAY NIGHT INTO FRIDAY.
ECMWF AND GFS AGREE THAT A CLOSED MID-LEVEL LOW WILL DEVELOP
ACROSS THE CENTRAL PLAINS ON FRIDAY NIGHT AND SHIFT INTO THE GREAT
LAKES REGION BY SATURDAY. AHEAD OF THIS FEATURE...CHANCE POPS
RETURN TO THE AREA. MODEL PREDICTABILITY A WEEK OUT MAKES IT
DIFFICULT TO PIN DOWN SPECIFICS IN FRONTAL PLACEMENT...HOWEVER
THIS PATTERN FAVORS THE POTENTIAL FOR OVERRUNNING ALONG WITH WARM
FRONTAL RAIN SHOWERS WELL AHEAD OF THE LOW.
TEMPERATURES WILL REBOUND TO WARMER THAN NORMAL THIS PERIOD WITH
VALUES FRIDAY AND SATURDAY ANYWHERE FROM 5 TO 10 DEGREES ABOVE
NORMAL.
&&
.AVIATION /11Z SUNDAY THROUGH THURSDAY/...
CONDITIONS SHOULD REMAIN MVFR THROUGH THE MORNING AND MUCH OF THE
AFTERNOON. THE EXCEPTIONS TO THIS WILL BE FKL/DUJ...WHERE LOW
CLOUDS HAVE SCATTERED OUT RESULTING IN VFR CONDITIONS...AND
MGW...WHERE MORNING SHOWERS ARE EXPECTED TO CAUSE IFR CEILINGS.
WITH WARM FRONT EXPECTED TO ARRIVE A BIT LATER IN THE DAY...HAVE
DELAYED MENTION OF RAIN AT ALL SITES EXCEPT MGW UNTIL THE
AFTERNOON HOURS. CEILINGS WILL LOWER TO IFR AFTER A FEW HOURS OF
RAIN.
WINDS WILL SHIFT FROM NORTHEAST TO THE SOUTHEAST DURING THE
DAY...WHICH COULD ALLOW FOR A BRIEF INCREASE OF WINDS AT KLBE DUE
TO DOWNSLOPING. WINDS WILL BECOME SOUTHERLY ONCE THE WARM FRONT
MOVES THROUGH THIS EVENING.
.OUTLOOK.../MONDAY THROUGH THURSDAY/...
MVFR AND PSBL IFR RESTRICTIONS WL CONTINUE WITH RAIN MONDAY AS A
COLD FRONT MOVES THROUGH. MVFR CONDITIONS ARE EXPECTED MONDAY NIGHT
INTO TUESDAY. LINGERING RAIN SHOWERS MAY CHANGE TO SCATTERED SNOW
SHOWERS BEFORE ENDING EARLY TUESDAY. HIGH PRES AND VFR CONDS ARE
EXPECTED LATER TUESDAY THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
957 AM EST SUN DEC 9 2012
.UPDATE...
ISSUED AT 956 AM EST SUN DEC 9 2012
THE SOUTHWARD SHIFT OF THE MODELS OVER THE LAST 18-24HRS WITH THE
SURFACE LOW AND IT TRANSFORMING INTO A SURFACE TROUGH TODAY HAS LED
TO AN INTERESTING DECISION WITH RESPECT TO SOME OF THE HAZARDS.
SNOW IS CURRENTLY SOUTHWEST OF A LINE FROM ASHLAND THROUGH
MILWAUKEE. LATEST SHORT RANGE AND HIRES MODELS INDICATING BEST
OPPORTUNITY FOR ADVISORY SNOW FROM THE SYSTEM ALONG THE WISCONSIN
BORDER AND NEAR LAKE MICHIGAN WITH SOME LAKE ENHANCEMENT LATE THIS
AFTERNOON THROUGH THE EVENING. AWAY FROM THIS AREA...VERY LOW
CONFIDENCE IN SEEING ENOUGH SNOW FOR ADVISORY CRITERIA FOR SOME
AREAS...ESPECIALLY FOR NORTHERN IRON...EASTERN GOGEBIC...SOUTHEAST
ONTONAGON AND SOUTHERN HOUGHTON COUNTIES. THEY WILL BE ON THE EDGE
OF THE BETTER SYSTEM SNOW AND AWAY FROM THE LAKE ENHANCED SNOW THAT
MAY SAVE THE ADVISORY FOR OTHER PARTS OF THE CWA NEAR LAKE SUPERIOR.
THE LAKE ENHANCEMENT WILL LIKELY INCREASE AFTER MIDNIGHT AS WINDS
TURN TO THE NORTH-NORTHEAST AND FAVOR THE WESTERN SHORELINE FROM
IRONWOOD THROUGH HOUGHTON AND THEN THE HIGHER TERRAIN OF EASTERN
BARAGA AND NORTHERN MARQUETTE COUNTIES...AND POTENTIALLY FAR WESTERN
ALGER COUNTY. THE MOST FAVORABLE PERIOD FOR LAKE ENHANCED SNOW WILL
BE LATE TONIGHT INTO THE FIRST PART OF TOMORROW MORNING. BUT...WITH
THE WINDS BACKING THROUGH TONIGHT AND MONDAY...THE OPPORTUNITY FOR
MORE THAN A BRIEF 1-3 INCHES WILL BE LIMITED.
BASED OFF LOCAL SNOW AND VEHICLE ACCIDENT DATA...EVEN SEEING 1IN OF
SNOW GREATLY INCREASES ACCIDENTS IN THE AREA. THUS...EVEN THOUGH
SOME OF THE MENTIONED AREAS OF CONCERN WILL LIKELY ONLY SEE 1-3IN OF
SNOW...WILL LEAVE THE ADVISORY IN PLACE AT THIS POINT. MADE
ADJUSTMENTS TO POPS AND SNOW AMOUNTS FOR TODAY TO BETTER MATCH
LATEST MODEL RUNS. THIS RESULTED IN A REDUCTION OF SNOW AMOUNTS IN
SOME AREAS OF AROUND 0.5-1.0IN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 528 AM EST SUN DEC 9 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM THE ROCKIES INTO THE CNTRL AND NRN PLAINS. A VIGOROUS SHORTWAVE
TROUGH EXTENDED FROM CNTRL SOUTH DAKOTA INTO NRN NEBRASKA.
UPSTREAM...ANOTHER SHRTWV WAS DIGGING SOUTHEAST INTO THE CNTRL
ROCKIES. AT THE SFC...EASTERLY FLOW WAS INCREASING OVER THE REGION
BTWN LOW PRES OVER SE SOUTH DAKOTA AND A RIDGE FROM SASK AND CNTRL
MANITOBA INTO NRN ONTARIO. STRONG 700-300 MB QVECTOR CONV AHEAD OF
THE SHORTWAVE ALONG WITH STEEP 700-500 MB LAPSE RATES FROM 7C TO
8C/KM SUPPORTED STRONG UPWARD MOTION AND AREAS OF MODERATE TO HEAVY
SNOW OVER WRN INTO CNTRL MN WHERE THE LOW LEVEL MOISTURE INFLOW WAS
MOST FAVORABLE.
THE MODELS HAVE TRENDED SOUTHWARD WITH THE SHRTWV AND ASSOCIATED SFC
LOW/TROUGH AS IT PROGRESSES TO THE EAST. SIMILAR TO PREVIOUS MODEL
RUNS...THE SHRTWV ALSO SHEARS OUT AND WEAKENS AS IT MOVES TO THE
NORTHEAST. IN ADDITION...THE DRY EASTERLY FLOW OUT OF ONTARIO INTO
UPPER MI WILL HELP DELAY THE ONSET OF THE SNOW AND MAY HELP LOWER
OVERALL SNOWFALL AMOUNTS. SO...WINTER WEATHER ADVISORY START TIMES
WERE ADJUSTED ACCORDINGLY.
THE STRONGEST 280K-290K ISENTROPIC LIFT AND 800-600 MB FGEN LATE
THIS AFTERNOON AND EVENING IS EXPECTED CLOSEST TO THE SRN CWA...FROM
NRN WI INTO NRN LAKE MI. MODELS QPF VALUES FROM 0.15 TO 0.40 INCH
ARE STILL POSSIBLE AS THE AREA OF MODERATE TO STRONG QVECTOR CONV
AND WAA/ISENTROPIC LIFT BRUSH THE CWA. WITH THE STRONGEST OMEGA
REMAINING ABOVE THE DENDRITIC GROWTH ZONE FROM ABOUT 5K TO 9K
FT...SNOW/WATER RATIOS SHOULD REMAIN AT OR BELOW 15/1. SYNOPTIC
SNOWFALL AMOUNTS IN THE 2 TO 5 INCH RANGE ARE POSSIBLE MAINLY LATE
THIS AFTERNOON AND THIS EVENING. THE WIDESPREAD SNOW SHOULD DIMINISH
OVERNIGHT AS THE SHORTWAVE MOVES OFF TO THE NE AND WEAKENS.
WITH 850 MB TEMPS AROUND -8C...THE HIGHER RES MODELS INDICATED THE
POTENTIAL FOR BANDS OF LAKE ENHANCED SNOW DEVELOPING OFF OF LAKE
MICHIGAN THAT MAY BOOST SNOW TOTALS FROM THE GARDEN PENINSULA TO
ESC AND MNM. THERE IS LESS CONFIDENCE THAT THE ERLY FLOW INTO THE
KEWEENAW WILL ADD TO SNOW AMOUNTS WITH THE STRONGER DYNAMICS TO THE
SOUTH AND THE INFLUENCE OF THE DRY EAST FLOW.
AS THE LOW LEVEL TROUGH SLIDES TO THE EAST...EXPECT CYCLONIC N TO NE
FLOW TO BRING AN INCREASE IN LAKE EFFECT SNOW TO NEAR IWD AND N
CNTRL UPPER MI LATE TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 528 AM EST SUN DEC 9 2012
SYNOPTIC FORCING WILL BE EAST OF THE AREA BY MONDAY MORNING.
HOWEVER...NORTHERLY AND NORTHEASTERLY WINDS WILL ALLOW LAKE EFFECT
TO LINGER INTO THE EARLY AFTERNOON HOURS. AS FLOW BECOMES MORE
ANTICYCLONIC PARAMETERS DO NOT SUGGEST LAKE SNOWS WILL BE OVERLY
HEAVY. THE BEST CHANCE FOR AN ADDITIONAL FEW INCHES OF SNOW WILL BE
OVER NW ONTONAGON COUNTY AND WESTERN GOGEBIC COUNTY BASED PRIMARILY
ON LONGER FETCH INTO THESE AREAS. THE HIGHER TERRAIN OF MARQUETTE
COUNTY MAY ALSO PICKUP ANOTHER INCH OR TWO DURING THE MORNING. SNOW
WILL BE ON THE WANE IN THESE AREAS THROUGH THE AFTERNOON.
IT DOESNT APPEAR THAT ANY OTHER SIGNIFICANT STORMS WILL AFFECT THE
UPPER GREAT LAKES THROUGH THE REMAINDER OF THE UPCOMING WORK WEEK.
WEAK SURFACE RIDGE AXIS WILL CROSS THE AREA MONDAY NIGHT WITH WINDS
BECOMING SOUTHERLY ACROSS THE AREA ON TUESDAY AS NEXT WEAK SHORTWAVE
APPROACHES THE AREA. 85H TEMPS WILL REMAIN LOW ENOUGH -10 TO -12 FOR
LES TO DEVELOP OFF LAKE MI. WITH THE PRIMARY BAND TRANSIENT ENOUGH
EXPECT AMOUNTS TO ONLY BE IN THE 1 TO 3 INCH RANGE OVER SE
SCHOOLCRAFT COUNTY INTO LUCE COUNTY.
AS SURFACE TROF PASS THROUGH THE AREA LATE TUESDAY WINDS WILL
BRIEFLY BECOME MORE WESTERLY WHICH MAY ALLOW FOR SOME LIGHT LES TO
RETURN TO THE KEWEENAW. WINDS WILL THEN BACK SOUTHERLY AGAIN AS NEXT
QUICK MOVING SHORTWAVE AND SURFACE LOW RACES EASTWARD ACROSS
SOUTHERN ONTARIO ON THURSDAY. BEST FORCING FOR PRECIPITATION SHOULD
GENERALLY REMAIN NORTH OF THE AREA.
MEDIUM RANGE MODELS STILL INDICATING SOME POTENTIAL FOR A MORE
SIGNIFICANT STORM FOR NEXT WEEKEND BUT CONFIDENCE IN ANY DETAILS ARE
VERY LOW. AS SEEN WITH THE CHALLENGES OF OUR CURRENT SYSTEM WHERE
THE INTERACTION OF NORTHERN AND SOUTHERN STREAM ENERGY WAS CRUCIAL
TO THE FORECAST AND NOT RESOLVED UNTIL JUST PRIOR TO THE
EVENT...TRYING TO GARNER ANY DETAILS ON A POTENTIAL SYSTEM A WEEK
AWAY IS A LOW CONFIDENCE PROPOSITION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 652 AM EST SUN DEC 9 2012
EXPECT PREDOMINANT VFR CONDITIONS THROUGH AT LEAST THIS MORNING AT
ALL THE TAF SITES WITH A RIDGE OF HIGH PRES AND AXIS OF LOW LEVEL
DRY AIR DOMINATING. THEN LATER TODAY...THE APPROACH OF LOW PRES WILL
BRING SNOW AND LOWER CIGS/VSBYS SW-NE TO UPR MI. CONTINUED WITH
TREND TOWARD A SLOWER ONSET OF SN/LOWER CONDITIONS BASED ON
NUMERICAL MODEL TRENDS SHOWING A FARTHER S TRACK FOR THE LOW PRES
AND MORE RESILIENT DRY AIR OVER THE NORTHERN GREAT LAKES.
ALTHOUGH SAW IS FARTHER TO THE NE...UPSLOPE ESE WIND MIGHT RESULT IN
AN EARLIER ARRIVAL OF THE PCPN/MVFR CIGS. BY EARLY EVNG...CONDITIONS
SHOULD DETERIORATE TO IFR AT ALL 3 LOCATIONS AND CONTINUE OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT
532 AM EST SUN DEC 9 2012
AN AREA OF LOW PRESSURE MOVING OUT OF SOUTHEAST SOUTH DAKOTA WILL
MOVE THROUGH MN TODAY AND THEN MERGE WITH A LOW DEVELOPING IN THE
GREAT LAKES TO LEAVE A TROUGH OVER NORTHERN WISCONSIN. THIS TROUGH
WILL INCREASE WINDS OUT OF THE EAST AND THEN NORTHEAST TODAY AND
TONIGHT. AT THIS TIME...THINKING WINDS WILL BE IN THE 20-30KT
RANGE...ALTHOUGH THERE COULD BE A FEW GALE FORCE GUSTS TO 35KTS OVER
THE WEST AS THE TROUGH SHARPENS LATE TONIGHT. BEHIND THIS FEATURE...A
SERIES OF WEAK RIDGES AND TROUGHS WILL AFFECT LAKE SUPERIOR DURING
THE REST OF THE WORK WEEK AND KEEP WINDS BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ006-007-013-014-085.
WINTER WEATHER ADVISORY UNTIL 7 AM EST /6 AM CST/ MONDAY FOR
MIZ004-010-084.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 1 PM EST
MONDAY FOR MIZ005.
WINTER WEATHER ADVISORY UNTIL 5 PM EST /4 PM CST/ MONDAY FOR
MIZ002-009.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ001-003.
WINTER WEATHER ADVISORY UNTIL 3 AM CST MONDAY FOR MIZ011-012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...JLB
LONG TERM...MZ
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
657 AM EST SUN DEC 9 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 528 AM EST SUN DEC 9 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM THE ROCKIES INTO THE CNTRL AND NRN PLAINS. A VIGOROUS SHORTWAVE
TROUGH EXTENDED FROM CNTRL SOUTH DAKOTA INTO NRN NEBRASKA.
UPSTREAM...ANOTHER SHRTWV WAS DIGGING SOUTHEAST INTO THE CNTRL
ROCKIES. AT THE SFC...EASTERLY FLOW WAS INCREASING OVER THE REGION
BTWN LOW PRES OVER SE SOUTH DAKOTA AND A RIDGE FROM SASK AND CNTRL
MANITOBA INTO NRN ONTARIO. STRONG 700-300 MB QVECTOR CONV AHEAD OF
THE SHORTWAVE ALONG WITH STEEP 700-500 MB LAPSE RATES FROM 7C TO
8C/KM SUPPORTED STRONG UPWARD MOTION AND AREAS OF MODERATE TO HEAVY
SNOW OVER WRN INTO CNTRL MN WHERE THE LOW LEVEL MOISTURE INFLOW WAS
MOST FAVORABLE.
THE MODELS HAVE TRENDED SOUTHWARD WITH THE SHRTWV AND ASSOCIATED SFC
LOW/TROUGH AS IT PROGRESSES TO THE EAST. SIMILAR TO PREVIOUS MODEL
RUNS...THE SHRTWV ALSO SHEARS OUT AND WEAKENS AS IT MOVES TO THE
NORTHEAST. IN ADDITION...THE DRY EASTERLY FLOW OUT OF ONTARIO INTO
UPPER MI WILL HELP DELAY THE ONSET OF THE SNOW AND MAY HELP LOWER
OVERALL SNOWFALL AMOUNTS. SO...WINTER WEATHER ADVISORY START TIMES
WERE ADJUSTED ACCORDINGLY.
THE STRONGEST 280K-290K ISENTROPIC LIFT AND 800-600 MB FGEN LATE
THIS AFTERNOON AND EVENING IS EXPECTED CLOSEST TO THE SRN CWA...FROM
NRN WI INTO NRN LAKE MI. MODELS QPF VALUES FROM 0.15 TO 0.40 INCH
ARE STILL POSSIBLE AS THE AREA OF MODERATE TO STRONG QVECTOR CONV
AND WAA/ISENTROPIC LIFT BRUSH THE CWA. WITH THE STRONGEST OMEGA
REMAINING ABOVE THE DENDRITIC GROWTH ZONE FROM ABOUT 5K TO 9K
FT...SNOW/WATER RATIOS SHOULD REMAIN AT OR BELOW 15/1. SYNOPTIC
SNOWFALL AMOUNTS IN THE 2 TO 5 INCH RANGE ARE POSSIBLE MAINLY LATE
THIS AFTERNOON AND THIS EVENING. THE WIDESPREAD SNOW SHOULD DIMINISH
OVERNIGHT AS THE SHORTWAVE MOVES OFF TO THE NE AND WEAKENS.
WITH 850 MB TEMPS AROUND -8C...THE HIGHER RES MODELS INDICATED THE
POTENTIAL FOR BANDS OF LAKE ENHANCED SNOW DEVELOPING OFF OF LAKE
MICHIGAN THAT MAY BOOST SNOW TOTALS FROM THE GARDEN PENINSULA TO
ESC AND MNM. THERE IS LESS CONFIDENCE THAT THE ERLY FLOW INTO THE
KEWEENAW WILL ADD TO SNOW AMOUNTS WITH THE STRONGER DYNAMICS TO THE
SOUTH AND THE INFLUENCE OF THE DRY EAST FLOW.
AS THE LOW LEVEL TROUGH SLIDES TO THE EAST...EXPECT CYCLONIC N TO NE
FLOW TO BRING AN INCREASE IN LAKE EFFECT SNOW TO NEAR IWD AND N
CNTRL UPPER MI LATE TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 528 AM EST SUN DEC 9 2012
SYNOPTIC FORCING WILL BE EAST OF THE AREA BY MONDAY MORNING.
HOWEVER...NORTHERLY AND NORTHEASTERLY WINDS WILL ALLOW LAKE EFFECT
TO LINGER INTO THE EARLY AFTERNOON HOURS. AS FLOW BECOMES MORE
ANTICYCLONIC PARAMETERS DO NOT SUGGEST LAKE SNOWS WILL BE OVERLY
HEAVY. THE BEST CHANCE FOR AN ADDITIONAL FEW INCHES OF SNOW WILL BE
OVER NW ONTONAGON COUNTY AND WESTERN GOGEBIC COUNTY BASED PRIMARILY
ON LONGER FETCH INTO THESE AREAS. THE HIGHER TERRAIN OF MARQUETTE
COUNTY MAY ALSO PICKUP ANOTHER INCH OR TWO DURING THE MORNING. SNOW
WILL BE ON THE WANE IN THESE AREAS THROUGH THE AFTERNOON.
IT DOESNT APPEAR THAT ANY OTHER SIGNIFICANT STORMS WILL AFFECT THE
UPPER GREAT LAKES THROUGH THE REMAINDER OF THE UPCOMING WORK WEEK.
WEAK SURFACE RIDGE AXIS WILL CROSS THE AREA MONDAY NIGHT WITH WINDS
BECOMING SOUTHERLY ACROSS THE AREA ON TUESDAY AS NEXT WEAK SHORTWAVE
APPROACHES THE AREA. 85H TEMPS WILL REMAIN LOW ENOUGH -10 TO -12 FOR
LES TO DEVELOP OFF LAKE MI. WITH THE PRIMARY BAND TRANSIENT ENOUGH
EXPECT AMOUNTS TO ONLY BE IN THE 1 TO 3 INCH RANGE OVER SE
SCHOOLCRAFT COUNTY INTO LUCE COUNTY.
AS SURFACE TROF PASS THROUGH THE AREA LATE TUESDAY WINDS WILL
BRIEFLY BECOME MORE WESTERLY WHICH MAY ALLOW FOR SOME LIGHT LES TO
RETURN TO THE KEWEENAW. WINDS WILL THEN BACK SOUTHERLY AGAIN AS NEXT
QUICK MOVING SHORTWAVE AND SURFACE LOW RACES EASTWARD ACROSS
SOUTHERN ONTARIO ON THURSDAY. BEST FORCING FOR PRECIPITATION SHOULD
GENERALLY REMAIN NORTH OF THE AREA.
MEDIUM RANGE MODELS STILL INDICATING SOME POTENTIAL FOR A MORE
SIGNIFICANT STORM FOR NEXT WEEKEND BUT CONFIDENCE IN ANY DETAILS ARE
VERY LOW. AS SEEN WITH THE CHALLENGES OF OUR CURRENT SYSTEM WHERE
THE INTERACTION OF NORTHERN AND SOUTHERN STREAM ENERGY WAS CRUCIAL
TO THE FORECAST AND NOT RESOLVED UNTIL JUST PRIOR TO THE
EVENT...TRYING TO GARNER ANY DETAILS ON A POTENTIAL SYSTEM A WEEK
AWAY IS A LOW CONFIDENCE PROPOSITION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 652 AM EST SUN DEC 9 2012
EXPECT PREDOMINANT VFR CONDITIONS THROUGH AT LEAST THIS MORNING AT
ALL THE TAF SITES WITH A RIDGE OF HIGH PRES AND AXIS OF LOW LEVEL
DRY AIR DOMINATING. THEN LATER TODAY...THE APPROACH OF LOW PRES WILL
BRING SNOW AND LOWER CIGS/VSBYS SW-NE TO UPR MI. CONTINUED WITH
TREND TOWARD A SLOWER ONSET OF SN/LOWER CONDITIONS BASED ON
NUMERICAL MODEL TRENDS SHOWING A FARTHER S TRACK FOR THE LOW PRES
AND MORE RESILIENT DRY AIR OVER THE NORTHERN GREAT LAKES.
ALTHOUGH SAW IS FARTHER TO THE NE...UPSLOPE ESE WIND MIGHT RESULT IN
AN EARLIER ARRIVAL OF THE PCPN/MVFR CIGS. BY EARLY EVNG...CONDITIONS
SHOULD DETERIORATE TO IFR AT ALL 3 LOCATIONS AND CONTINUE OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT
532 AM EST SUN DEC 9 2012
AN AREA OF LOW PRESSURE MOVING OUT OF SOUTHEAST SOUTH DAKOTA WILL
MOVE THROUGH MN TODAY AND THEN MERGE WITH A LOW DEVELOPING IN THE
GREAT LAKES TO LEAVE A TROUGH OVER NORTHERN WISCONSIN. THIS TROUGH
WILL INCREASE WINDS OUT OF THE EAST AND THEN NORTHEAST TODAY AND
TONIGHT. AT THIS TIME...THINKING WINDS WILL BE IN THE 20-30KT
RANGE...ALTHOUGH THERE COULD BE A FEW GALE FORCE GUSTS TO 35KTS OVER
THE WEST AS THE TROUGH SHARPENS LATE TONIGHT. BEHIND THIS FEATURE...A
SERIES OF WEAK RIDGES AND TROUGHS WILL AFFECT LAKE SUPERIOR DURING
THE REST OF THE WORK WEEK AND KEEP WINDS BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ006-007-013-014-085.
WINTER WEATHER ADVISORY FROM NOON EST /11 AM CST/ TODAY TO 7 AM
EST /6 AM CST/ MONDAY FOR MIZ004-010-084.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 1 PM EST
MONDAY FOR MIZ005.
WINTER WEATHER ADVISORY FROM 10 AM EST /9 AM CST/ THIS MORNING
TO 5 PM EST /4 PM CST/ MONDAY FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ001-003.
WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 3 AM CST
MONDAY FOR MIZ011-012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MZ
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
533 AM EST SUN DEC 9 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 528 AM EST SUN DEC 9 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM THE ROCKIES INTO THE CNTRL AND NRN PLAINS. A VIGOROUS SHORTWAVE
TROUGH EXTENDED FROM CNTRL SOUTH DAKOTA INTO NRN NEBRASKA.
UPSTREAM...ANOTHER SHRTWV WAS DIGGING SOUTHEAST INTO THE CNTRL
ROCKIES. AT THE SFC...EASTERLY FLOW WAS INCREASING OVER THE REGION
BTWN LOW PRES OVER SE SOUTH DAKOTA AND A RIDGE FROM SASK AND CNTRL
MANITOBA INTO NRN ONTARIO. STRONG 700-300 MB QVECTOR CONV AHEAD OF
THE SHORTWAVE ALONG WITH STEEP 700-500 MB LAPSE RATES FROM 7C TO
8C/KM SUPPORTED STRONG UPWARD MOTION AND AREAS OF MODERATE TO HEAVY
SNOW OVER WRN INTO CNTRL MN WHERE THE LOW LEVEL MOISTURE INFLOW WAS
MOST FAVORABLE.
THE MODELS HAVE TRENDED SOUTHWARD WITH THE SHRTWV AND ASSOCIATED SFC
LOW/TROUGH AS IT PROGRESSES TO THE EAST. SIMILAR TO PREVIOUS MODEL
RUNS...THE SHRTWV ALSO SHEARS OUT AND WEAKENS AS IT MOVES TO THE
NORTHEAST. IN ADDITION...THE DRY EASTERLY FLOW OUT OF ONTARIO INTO
UPPER MI WILL HELP DELAY THE ONSET OF THE SNOW AND MAY HELP LOWER
OVERALL SNOWFALL AMOUNTS. SO...WINTER WEATHER ADVISORY START TIMES
WERE ADJUSTED ACCORDINGLY.
THE STRONGEST 280K-290K ISENTROPIC LIFT AND 800-600 MB FGEN LATE
THIS AFTERNOON AND EVENING IS EXPECTED CLOSEST TO THE SRN CWA...FROM
NRN WI INTO NRN LAKE MI. MODELS QPF VALUES FROM 0.15 TO 0.40 INCH
ARE STILL POSSIBLE AS THE AREA OF MODERATE TO STRONG QVECTOR CONV
AND WAA/ISENTROPIC LIFT BRUSH THE CWA. WITH THE STRONGEST OMEGA
REMAINING ABOVE THE DENDRITIC GROWTH ZONE FROM ABOUT 5K TO 9K
FT...SNOW/WATER RATIOS SHOULD REMAIN AT OR BELOW 15/1. SYNOPTIC
SNOWFALL AMOUNTS IN THE 2 TO 5 INCH RANGE ARE POSSIBLE MAINLY LATE
THIS AFTERNOON AND THIS EVENING. THE WIDESPREAD SNOW SHOULD DIMINISH
OVERNIGHT AS THE SHORTWAVE MOVES OFF TO THE NE AND WEAKENS.
WITH 850 MB TEMPS AROUND -8C...THE HIGHER RES MODELS INDICATED THE
POTENTIAL FOR BANDS OF LAKE ENHANCED SNOW DEVELOPING OFF OF LAKE
MICHIGAN THAT MAY BOOST SNOW TOTALS FROM THE GARDEN PENINSULA TO
ESC AND MNM. THERE IS LESS CONFIDENCE THAT THE ERLY FLOW INTO THE
KEWEENAW WILL ADD TO SNOW AMOUNTS WITH THE STRONGER DYNAMICS TO THE
SOUTH AND THE INFLUENCE OF THE DRY EAST FLOW.
AS THE LOW LEVEL TROUGH SLIDES TO THE EAST...EXPECT CYCLONIC N TO NE
FLOW TO BRING AN INCREASE IN LAKE EFFECT SNOW TO NEAR IWD AND N
CNTRL UPPER MI LATE TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 528 AM EST SUN DEC 9 2012
SYNOPTIC FORCING WILL BE EAST OF THE AREA BY MONDAY MORNING.
HOWEVER...NORTHERLY AND NORTHEASTERLY WINDS WILL ALLOW LAKE EFFECT
TO LINGER INTO THE EARLY AFTERNOON HOURS. AS FLOW BECOMES MORE
ANTICYCLONIC PARAMETERS DO NOT SUGGEST LAKE SNOWS WILL BE OVERLY
HEAVY. THE BEST CHANCE FOR AN ADDITIONAL FEW INCHES OF SNOW WILL BE
OVER NW ONTONAGON COUNTY AND WESTERN GOGEBIC COUNTY BASED PRIMARILY
ON LONGER FETCH INTO THESE AREAS. THE HIGHER TERRAIN OF MARQUETTE
COUNTY MAY ALSO PICKUP ANOTHER INCH OR TWO DURING THE MORNING. SNOW
WILL BE ON THE WANE IN THESE AREAS THROUGH THE AFTERNOON.
IT DOESNT APPEAR THAT ANY OTHER SIGNIFICANT STORMS WILL AFFECT THE
UPPER GREAT LAKES THROUGH THE REMAINDER OF THE UPCOMING WORK WEEK.
WEAK SURFACE RIDGE AXIS WILL CROSS THE AREA MONDAY NIGHT WITH WINDS
BECOMING SOUTHERLY ACROSS THE AREA ON TUESDAY AS NEXT WEAK SHORTWAVE
APPROACHES THE AREA. 85H TEMPS WILL REMAIN LOW ENOUGH -10 TO -12 FOR
LES TO DEVELOP OFF LAKE MI. WITH THE PRIMARY BAND TRANSIENT ENOUGH
EXPECT AMOUNTS TO ONLY BE IN THE 1 TO 3 INCH RANGE OVER SE
SCHOOLCRAFT COUNTY INTO LUCE COUNTY.
AS SURFACE TROF PASS THROUGH THE AREA LATE TUESDAY WINDS WILL
BRIEFLY BECOME MORE WESTERLY WHICH MAY ALLOW FOR SOME LIGHT LES TO
RETURN TO THE KEWEENAW. WINDS WILL THEN BACK SOUTHERLY AGAIN AS NEXT
QUICK MOVING SHORTWAVE AND SURFACE LOW RACES EASTWARD ACROSS
SOUTHERN ONTARIO ON THURSDAY. BEST FORCING FOR PRECIPITATION SHOULD
GENERALLY REMAIN NORTH OF THE AREA.
MEDIUM RANGE MODELS STILL INDICATING SOME POTENTIAL FOR A MORE
SIGNIFICANT STORM FOR NEXT WEEKEND BUT CONFIDENCE IN ANY DETAILS ARE
VERY LOW. AS SEEN WITH THE CHALLENGES OF OUR CURRENT SYSTEM WHERE
THE INTERACTION OF NORTHERN AND SOUTHERN STREAM ENERGY WAS CRUCIAL
TO THE FORECAST AND NOT RESOLVED UNTIL JUST PRIOR TO THE
EVENT...TRYING TO GARNER ANY DETAILS ON A POTENTIAL SYSTEM A WEEK
AWAY IS A LOW CONFIDENCE PROPOSITION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY MORNING) ISSUED AT
1239 AM EST SUN DEC 9 2012
EXPECT PREDOMINANT VFR CONDITIONS THRU AT LEAST THIS MRNG AT ALL THE
TAF SITES WITH RDG OF HI PRES/AXIS OF LLVL DRY AIR DOMINATING. THEN
LATER TODAY...APRCH OF LO PRES WL BRING SN AND LOWER CIGS/VSBYS
SW-NE TO UPR MI. TENDED TO SLOW DOWN THE ONSET OF SN/LOWER
CONDITIONS BASED ON NUMERICAL MODEL TRENDS SHOWING A FARTHER S TRACK
FOR THE LO PRES/MORE RESILIENT DRY AIR OVER THE UPR LKS. ALTHOUGH
SAW IS FARTHER TO THE NE...UPSLOPE ESE WIND MIGHT RESULT IN AN
EARLIER ARRIVAL OF THE PCPN/MVFR CIGS. BY EARLY EVNG...CONDITIONS
SHOULD DETERIORATE TO IFR AT ALL 3 LOCATIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT
532 AM EST SUN DEC 9 2012
AN AREA OF LOW PRESSURE MOVING OUT OF SOUTHEAST SOUTH DAKOTA WILL
MOVE THROUGH MN TODAY AND THEN MERGE WITH A LOW DEVELOPING IN THE
GREAT LAKES TO LEAVE A TROUGH OVER NORTHERN WISCONSIN. THIS TROUGH
WILL INCREASE WINDS OUT OF THE EAST AND THEN NORTHEAST TODAY AND
TONIGHT. AT THIS TIME...THINKING WINDS WILL BE IN THE 20-30KT
RANGE...ALTHOUGH THERE COULD BE A FEW GALE FORCE GUSTS TO 35KTS OVER
THE WEST AS THE TROUGH SHARPENS LATE TONIGHT. BEHIND THIS FEATURE...A
SERIES OF WEAK RIDGES AND TROUGHS WILL AFFECT LAKE SUPERIOR DURING
THE REST OF THE WORK WEEK AND KEEP WINDS BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ006-007-013-014-085.
WINTER WEATHER ADVISORY FROM NOON EST /11 AM CST/ TODAY TO 7 AM
EST /6 AM CST/ MONDAY FOR MIZ004-010-084.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 1 PM EST
MONDAY FOR MIZ005.
WINTER WEATHER ADVISORY FROM 10 AM EST /9 AM CST/ THIS MORNING
TO 5 PM EST /4 PM CST/ MONDAY FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ001-003.
WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 3 AM CST
MONDAY FOR MIZ011-012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MZ
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
539 AM CST SUN DEC 9 2012
.DISCUSSION...
OVERVIEW...UPDATED FORECAST TO ACCOUNT FOR SOUTHERLY SHIFT OF
WINTER STORM AFFECTING THE AREA TODAY. THIS PUTS THE TWIN CITIES
METRO AREA RIGHT IN THE SWATH OF HEAVIEST SNOWFALL. MINOR
ADJUSTMENTS TO THE WINTER WEATHER HEADLINES OVERNIGHT. ADDED
MCLEOD AND MEEKER COUNTIES TO THE BLIZZARD WARNING AND LE
SUEUR...RICE AND GOODHUE TO THE WINTER STORM WARNING. FRESH SNOW
COVER MIGHT KEEP US A BIT COOLER THAN FORECAST TEMPERATURES THIS
WEEK. NO MAJOR CHANGES TO FORECAST BEYOND THIS WEEKEND.
BEEN WATCHING PERSISTENT LIGHT TO MODERATE SNOWFALL ACROSS
MINNESOTA FOR THE LAST 4 TO 5 HOURS NOW. AIRPORTS REPORTING MAINLY
REPORTING 3/4SM TO 1 1/2SM VISIBILITY AND A LOT OF AREA HAVE
PICKED UP AND INCH OR TWO OF SNOW. FINALLY...STARTING TO GET
SITES MEASURE IN WISCONSIN...BUT REALLY AREN`T SEEING MUCH HEAVY
SNOW OUT THERE EARLY THIS MORNING AFTER THE INITIAL BAND NEAR THE
MN/SD BORDER BROKE UP AROUND MIDNIGHT. SNOW RATES IN YELLOW
MEDICINE AND LAC QUI PARLE WERE NEAR AN INCH PER HOUR LAST
EVENING...WITH SITES NEAR THE STATE LINE QUICKLY PICKING UP 4-5"
IN A FEW HOURS TIME. THE 00Z MPX SOUNDING...ALONG
FSD AND ABR VAD PROFILES SHOW A STRONG WAA REGIME...WHICH SHOULD
BE ENHANCED BY THE APPROACHING UPPER TROUGH AND INCREASING MID-
LEVEL FRONTAL-GENESIS. CONSEQUENTLY...THIS BAND IS EXPECTED TO
PERSIST INTO SWRN MN...FAR NERN SD...AND FAR SERN ND. SNOWFALL
RATES ARE GENERALLY EXPECTED TO REMAIN BELOW 1 INCH/HOUR BUT
BRIEF/ISOLATED RATES GREATER THAN 1 INCH/HOUR ARE POSSIBLE.
THERE WAS GOOD MODEL CONSENSUS AMONG THE 09.00Z RUNS OF A SLIGHT
SOUTHWARD SHIFT TO THE SURFACE LOW TRACK. THE RAP13 AND 00Z NAM
WERE THE FIRST TO SUGGEST THIS AND THE 00Z GFS CAME ALMOST
PERFECTLY IN LINE WITH THE NAM. WHAT IS A CONCERN IS THE ALMOST
IDENTICAL PLACEMENT OF 14-16" SNOWFALL IN THE WEST TWIN CITIES
METRO AND COUNTIES JUST WEST OF HERE. 09.00Z LOCAL WRF-ARW AND
09.08Z RAP ALSO HAVE HIGH END SNOWFALL RIGHT IN THE CENTER OF OUR CWA
GIVEN THE SLOW MOVEMENT AND TRACK OF THE SURFACE/850MB/700MB LOW
CENTERS. THE RAP HAS 20 INCHES...LIKELY OVERDONE BUT IT`S HINTING
AT THE POTENTIAL FOR SOMETHING SIGNIFICANT. THE PV FEATURE
ASSOCIATED WITH THIS SYSTEM IS IMPRESSIVE AND ITS ORIENTATION
SUGGESTS A LONGER THAN EXPECTED PERIOD OF SNOW TODAY. ALREADY
SEEING EVIDENCE OF A CIRCULATION IN THE REFLECTIVITY ACROSS SW
MN. THIS SHOULD FEATURE SHOULD LIFT NORTH...BECOME ANCHORED
PRODUCE 0.75-1.5" SNOWFALL RATES LATE THIS MORNING AND EARLY THIS
AFTERNOON. INCREASED THE SNOWFALL IN THE TWIN CITIES METRO TO 8-11
INCHES...AND HOPEFULLY THAT IS ENOUGH TO COVER IT. DEPTH OF SNOW
GROWTH REGION ISN`T OVERLY IMPRESSIVE...BUT WE SHOULD STILL MANAGE
SNOW RATIOS NEAR CLIMATOLOGY 13-14:1 OR SO. FURTHERMORE...ON THE
NOSE OF THE PV FEATURE...JUST AHEAD OF DRY SLOT...STATIC STABILITY
BECOMES WEAK AND SUGGESTS BANDED PRECIP COULD BE FACTORING IN TO
HELP SNOW TOTALS. OTHERWISE...WARMED TEMPS TONIGHT WITH THE SLOWER
PROGRESSION AND KEPT THE WIND ABOUT THE SAME...PERHAPS A BIT LESS.
THEREFORE WIND CHILLS AREN`T AS COLD WITH THIS MORNING`S FORECAST.
IN THE EXTENDED...HEIGHTS BEGIN TO BUILD BACK ON WEDNESDAY...SO
SHOULD ALREADY SEE MODERATING TEMPS FROM A COLD MONDAY AND
TUESDAY. A COUPLE WEAK CLIPPER SYSTEM LOOK TO PASS NORTH OF THE
AREA THIS WEEK...BUT THERE IS ANOTHER POTENTIALLY SIGNIFICANT
STORM ON THE HORIZON 6-7 DAYS FROM NOW.
&&
.AVIATION.../12Z TAF ISSUANCE/
OVER THE NEXT 6 HRS...CONDS WILL DETERIORATE RAPIDLY WITH MOST TAF
SITES GOING TO NEAR MINIMUMS. STORM SYSTEM WAS BEGINNING TO
DEVELOP A STRONG CIRCULATION NORTHWEST OF KFSD WITH A LARGE AREA
OF ENERGY THAT WILL LIFT TO THE E/NE DURING THE MORNING. SNOWFALL
RATES WILL LIKELY INCREASE TO 1...OR EVEN 2 INCHES PER HOUR DURING
THE HEIGHT OF THE STORM. TAFS ARE BASED ON CURRENT RAP MODEL SFC
WINDS AND FORECAST REFLECTIVITY OF THE SPC/WRF. AXN WILL LIKELY BE
ON THE NW SIDE OF THE LOWEST CIGS/VSBYS...WITH STC/RNH/MSP LIKELY
THE WORSE AREA DURING THE 15-03Z TIME FRAME. AS THE STORM SYSTEM
MOVES EASTWARD ACROSS SOUTHERN MN TODAY...EXPECT A BAND OF
MODERATE TO HEAVY SNOWFALL ALONG A LINE FROM KMVE TO KMGG TO KOEO.
AS THE STORM BEGINS TO PIVOT...EXPECT THE BANDS OF SNOW TO SLOWLY
MOVE FROM THE WEST TO THE EAST...THEN SE AS THE STORM MOVES OFF TO
THE WESTERN GREAT LAKES. THERE WILL BE A PERIOD OF 1/4SM +SN AND
VV002 OR LOWER. EXPECT SFC WINDS TO INCREASE AT AXN BY
15-18Z...THAN AT RWF BY 18-21Z. AFT 00-03Z CONDS WILL SLOWLY
IMPROVE WITH IFR...OR MVFR CIGS/VSBYS WITH BLSN CONTINUING
ACROSS AXN/RWF.
KMSP...
THERE IS A 3 HR PERIOD OF IFR/MVFR CONDS WITH -SN...BUT AFT 15Z
EXPECT CONDS TO DETERIORATE RAPIDLY WITH VSBYS DROPPING TO LESS
THAN 3/4SM AND CIGS LOWERING TO 500` OR EVEN LOWER. THERE IS A
PERIOD DURING THE AFTN WHERE VSBYS COULD DROP TO 1/4SM +SN AND
VV002. SFC WINDS WILL BE PREDOMINATE FROM THE E/SE THIS
MORNING/AFTN WITH SOME GUSTS OVER 20 KTS POSSIBLE BY MID MORNING.
WINDS WILL SHIFT TO THE E/NE AFT 21Z...THEN BECOME N/NNE BY 00-03Z
AND GUSTY. EVENTUALLY WINDS WILL SHIFT TO THE N/NNW AFT 06Z WITH
CIGS/VSBYS SLOWLY IMPROVING. DECIDED NOT TO INCLUDE A TEMPORARY
GROUP DUE TO UNCERTAINTIES OF TIMING OF WHEN THE WORSE CONDS
DEVELOP THIS MORNING/AFTN. TAFS WILL LIKELY BE AMD AS THIS SYSTEM
EVOLVES.
/OUTLOOK FOR KMSP/
MON...MVFR/IFR CIGS POSSIBLE EARLY. THEN VFR. WINDS WNW AT 10G15KTS.
TUE...MVFR/IFR CIGS POSSIBLE. FLURRIES. WINDS SW AT 10G15KTS.
WED...MVFR/IFR CIGS POSSIBLE EARLY. WINDS S AT 10KTS. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR ANOKA-BENTON-
CARVER-CHISAGO-DAKOTA-GOODHUE-HENNEPIN-ISANTI-KANABEC-LE
SUEUR-MILLE LACS-MORRISON-RAMSEY-RICE-SCOTT-SHERBURNE-
STEARNS-TODD-WASHINGTON-WRIGHT.
WINTER STORM WARNING UNTIL 11 AM CST THIS MORNING FOR CHIPPEWA-
DOUGLAS-KANDIYOHI-LAC QUI PARLE-MCLEOD-MEEKER-POPE-RENVILLE-
SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE.
BLIZZARD WARNING FROM 11 AM THIS MORNING TO MIDNIGHT CST TONIGHT
FOR BROWN-CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-MCLEOD-
MEEKER-NICOLLET-POPE-REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-
YELLOW MEDICINE.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BLUE
EARTH-FARIBAULT-FREEBORN-MARTIN-STEELE-WASECA-WATONWAN.
WINTER WEATHER ADVISORY UNTIL 11 AM CST THIS MORNING FOR BROWN-
NICOLLET-REDWOOD.
WI...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BARRON-
CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
CLF/JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
413 AM CST SUN DEC 9 2012
.DISCUSSION...
OVERVIEW...UPDATED FORECAST TO ACCOUNT FOR SOUTHERLY SHIFT OF
WINTER STORM AFFECTING THE AREA TODAY. THIS PUTS THE TWIN CITIES
METRO AREA RIGHT IN THE SWATH OF HEAVIEST SNOWFALL. MINOR
ADJUSTMENTS TO THE WINTER WEATHER HEADLINES OVERNIGHT. ADDED
MCLEOD AND MEEKER COUNTIES TO THE BLIZZARD WARNING AND LE
SUEUR...RICE AND GOODHUE TO THE WINTER STORM WARNING. FRESH SNOW
COVER MIGHT KEEP US A BIT COOLER THAN FORECASTED TEMPERATURES THIS
WEEK. NO MAJOR CHANGES TO FORECAST BEYOND THIS WEEKEND.
BEEN WATCHING PERSISTENT LIGHT TO MODERATE SNOWFALL ACROSS
MINNESOTA FOR THE LAST 4 TO 5 HOURS NOW. AIRPORTS REPORTING MAINLY
REPORTING 3/4SM TO 1 1/2SM VISIBILITY AND A LOT OF AREA HAVE
PICKED UP AND INCH OR TWO OF SNOW. FINALLY...STARTING TO GET
SITES MEASURE IN WISCONSIN...BUT REALLY AREN`T SEEING MUCH HEAVY
SNOW OUT THERE EARLY THIS MORNING AFTER THE INITIAL BAND NEAR THE
MN/SD BORDER BROKE UP AROUND MIDNIGHT. SNOW RATES IN YELLOW
MEDICINE AND LAC QUI PARLE WERE NEAR AN INCH PER HOUR LAST
EVENING...WITH SITES NEAR THE STATE LINE QUICKLY PICKING UP 4-5"
IN A FEW HOURS TIME. THE 00Z MPX SOUNDING...ALONG
FSD AND ABR VAD PROFILES SHOW A STRONG WAA REGIME...WHICH SHOULD
BE ENHANCED BY THE APPROACHING UPPER TROUGH AND INCREASING MID-
LEVEL FRONTOGENESIS. CONSEQUENTLY...THIS BAND IS EXPECTED TO
PERSIST INTO SWRN MN...FAR NERN SD...AND FAR SERN ND. SNOWFALL
RATES ARE GENERALLY EXPECTED TO REMAIN BELOW 1 INCH/HOUR BUT
BRIEF/ISOLATED RATES GREATER THAN 1 INCH/HOUR ARE POSSIBLE.
THERE WAS GOOD MODEL CONSENSUS AMONG THE 09.00Z RUNS OF A SLIGHT
SOUTHWARD SHIFT TO THE SURFACE LOW TRACK. THE RAP13 AND 00Z NAM
WERE THE FIRST TO SUGGEST THIS AND THE 00Z GFS CAME ALMOST
PERFECTLY IN LINE WITH THE NAM. WHAT IS A CONCERN IS THE ALMOST
IDENTICAL PLACEMENT OF 14-16" SNOWFALL IN THE WEST TWIN CITIES
METRO AND COUNTIES JUST WEST OF HERE. 09.00Z LOCAL WRF-ARW AND
09.08Z RAP ALSO HAVE HIGH END SNOWFALL RIGHT IN THE CENTER OF OUR CWA
GIVEN THE SLOW MOVEMENT AND TRACK OF THE SURFACE/850MB/700MB LOW
CENTERS. THE RAP HAS 20 INCHES...LIKELY OVERDONE BUT IT`S HINTING
AT THE POTENTIAL FOR SOMETHING SIGNIFICANT. THE PV FEATURE
ASSOCIATED WITH THIS SYSTEM IS IMPRESSIVE AND ITS ORIENTATION
SUGGESTS A LONGER THAN EXPECTED PERIOD OF SNOW TODAY. ALREADY
SEEING EVIDENCE OF A CIRCULATION IN THE REFLECTIVITY ACROSS SW
MN. THIS SHOULD FEATURE SHOULD LIFT NORTH...BECOME ANCHORED
PRODUCE 0.75-1.5" SNOWFALL RATES LATE THIS MORNING AND EARLY THIS
AFTERNOON. INCREASED THE SNOWFALL IN THE TWIN CITIES METRO TO 8-11
INCHES...AND HOPEFULLY THAT IS ENOUGH TO COVER IT. DEPTH OF SNOW
GROWTH REGION ISN`T OVERLY IMPRESSIVE...BUT WE SHOULD STILL MANAGE
SNOW RATIOS NEAR CLIMATOLOGY 13-14:1 OR SO. FURTHERMORE...ON THE
NOSE OF THE PV FEATURE...JUST AHEAD OF DRY SLOT...STATIC STABILITY
BECOMES WEAK AND SUGGESTS BANDED PRECIP COULD BE FACTORING IN TO
HELP SNOW TOTALS. OTHERWISE...WARMED TEMPS TONIGHT WITH THE SLOWER
PROGRESSION AND KEPT THE WIND ABOUT THE SAME...PERHAPS A BIT LESS.
THEREFORE WIND CHILLS AREN`T AS COLD WITH THIS MORNING`S FORECAST.
IN THE EXTENDED...HEIGHTS BEGIN TO BUILD BACK ON WEDNESDAY...SO
SHOULD ALREADY SEE MODERATING TEMPS FROM A COLD MONDAY AND
TUESDAY. A COUPLE WEAK CLIPPER SYSTEM LOOK TO PASS NORTH OF THE
AREA THIS WEEK...BUT THERE IS ANOTHER POTENTIALLY SIGNIFICANT
STORM ON THE HORIZON 6-7 DAYS FROM NOW.
&&
.AVIATION.../06Z TAF ISSUANCE/
SIGNIFICANT SOUTHERN SHIFT ALONG WITH A BIT OF A SLOWING OCCURRED
WITH 00Z MODEL RUNS AND THIS PLACES ALL MPX TERMINALS WITHIN THE
HEART OF WHAT LOOKS TO BE AN IMPRESSIVE SNOW BAND...WITH 6-10 INCH
SNOW TOTALS /AND POSSIBLY MORE AT STC...MSP...RNH/ NOW EXPECTED. SFC
LOW RIGHT NOW IS CENTERED ALONG I-90 NEAR CHAMBERLAIN...SD. 00Z
NAM/GFS ALONG WITH THE RAP TRACK THIS LOW RIGHT DOWN I-90 THROUGH
THE DAY SUNDAY...PLACING THE MPX TERMINALS WITHIN THE HEAVIEST
SNOW. HAVE ALREADY BEEN GETTING SNOWFALL RATES OF AN INCH PLUS PER
HOUR IN WRN MN...SO CONTINUED TO ADVERTISE PROLONGED PERIODS OF
1/2SM VIS AT ALL TERMINALS...BUT TENDED TO SHIFT THAT MENTION OUT
IN TIME WITH THE SLOWING. ANOTHER ASPECT OF THE SLOWING WAS THE
NEED TO SLOW THE BACKING OF WINDS FROM THE EAST OVER TO THE
NW...ALONG WITH A TEMPERING OF SPEEDS SOME...AS NAM NOW SHOWING
GUST POTENTIAL GREATER THAN 35 KTS AT ONLY RWF. AS THIS TAF PERIOD
COMES TO AN END...CLEARING WILL START WORKING INTO WRN MN...WITH
VFR CONDITIONS EXPECTED AS WE START GOING A LITTLE BEYOND THIS TAF
PERIOD.
KMSP...ALL GUIDANCE NOW PUTTING MSP IN THE CROSS-HAIRS FOR THE
HEAVIEST SNOW WITH THIS EVENT...SO SIGNIFICANTLY DEGRADED
TAF...WITH LIFR VIS SNOW NOW EXTENDING WELL OUT INTO THE
AFTERNOON. LOOKING AT THE NAM ALONG WITH CURRENT RADAR...EXPECTING
TWO BURSTS OF SNOW THIS PERIOD. FIRST WILL COME BETWEEN 8Z AND 12Z
AS WARM ADVECTIVE WING OF PRECIP SWINGS THROUGH...WITH THE
NEXT...MORE PROLONGED BOUT OF HEAVY SNOW HITTING BETWEEN 14Z AND
22Z AS THE MAIN UPPER FORCING MOVES IN. THIS IS WHEN MAJORITY OF
ACCUMULATIONS SHOULD OCCUR...WITH SEVERAL OF THESE HOURS LIKELY
SEEING RATES AROUND 1 INCH AN HOUR. THIS TAF MAY A BIT PESSIMISTIC
WITH THE LENGTH OF 1/2SM VIS...BUT FEEL PRETTY CONFIDENT IN
WINDOWS OF HEAVIER SNOW THAT ARE INDICATED WITH TAF. AVIATION
WEATHER WARNING WILL ALSO BE ISSUED SHORTLY FOR ACCUMULATIONS
EXCEEDING 3/4 OF AN INCH PER HOUR. AS FOR STORM TOTAL...WOULD PUT
MSP ON THE HIGHER END OF THE SCALE WITH 8-10 INCHES LOOKING MORE
AND MORE LIKELY.
/OUTLOOK FOR KMSP/
MON...MVFR/IFR CIGS POSSIBLE EARLY. THEN VFR. WINDS WNW AT 10G15KTS.
TUE...MVFR/IFR CIGS POSSIBLE. WINDS SW AT 10G15KTS.
WED...VFR. WINDS SE AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR ANOKA-BENTON-
CARVER-CHISAGO-DAKOTA-GOODHUE-HENNEPIN-ISANTI-KANABEC-LE
SUEUR-MILLE LACS-MORRISON-RAMSEY-RICE-SCOTT-SHERBURNE-
STEARNS-TODD-WASHINGTON-WRIGHT.
WINTER STORM WARNING UNTIL 11 AM CST THIS MORNING FOR CHIPPEWA-
DOUGLAS-KANDIYOHI-LAC QUI PARLE-MCLEOD-MEEKER-POPE-RENVILLE-
SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE.
BLIZZARD WARNING FROM 11 AM THIS MORNING TO MIDNIGHT CST TONIGHT
FOR BROWN-CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-MCLEOD-
MEEKER-NICOLLET-POPE-REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-
YELLOW MEDICINE.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BLUE
EARTH-FARIBAULT-FREEBORN-MARTIN-STEELE-WASECA-WATONWAN.
WINTER WEATHER ADVISORY UNTIL 11 AM CST THIS MORNING FOR BROWN-
NICOLLET-REDWOOD.
WI...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BARRON-
CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1025 AM EST SUN DEC 9 2012
.SYNOPSIS...
A COLD FRONT FROM NEW ENGLAND TO THE TENNESSEE VALLEY WILL MOVE
SLOWLY SOUTHEAST TODAY BEFORE STALLING AND PUSHING BACK NORTH AS
WARM FRONT TONIGHT. A MUCH STRONGER COLD FRONT WILL CROSS THROUGH
THE AREA FROM THE WEST MONDAY EVENING. COOL HIGH PRESSURE WILL BUILD
IN BEHIND THE FRONT FOR TUESDAY INTO FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM EST SUNDAY...
LATEST SURFACE OBSERVATIONS INDICATE THE COLD FRONT IS SITUATED
JUST NORTHWEST OF OUR AREA THIS MORNING...STRETCHING THROUGH THE
CENTRAL PORTIONS OF KENTUCKY AND WEST VIRGINIA INTO NORTHERN
VIRGINIA. THE IMMEDIATE CONCERN IS A BAND OF SHOWER ACTIVITY
MAKING ITS WAY ACROSS KENTUCKY...RIDING ALONG THE FRONT. EXPECT
THESE SHOWERS TO SKIRT OUR MOUNTAIN EMPIRE COUNTIES BEGINNING
AROUND NOON...AND CONTINUE MOVING NORTHEAST ACROSS THE ALLEGHANY
HIGHLANDS THROUGH THE AFTERNOON BEFORE MOVING AWAY. SMALLER...MORE
SUBTLE DISTURBANCES PASSING ACROSS THE AREA WILL TRIGGER
SPOTTIER...LESS ORGANIZED SHOWER ACTIVITY ELSEWHERE THROUGH THE
DAY AS WELL.
AS THE DISTURBANCE TRIGGERING THESE SHOWERS MOVES NORTH...IT WILL
HELP PUSH THE COLD FRONT SOUTH INTO THE FOOTHILLS. OUR LOCAL WRF
AND RAP FORECAST MODELS INDICATED THE WEDGE REACHING THE ROANOKE
RIVER BY THE END OF THE DAY...BEFORE ADVANCING SLOWLY BACK NORTH
TONIGHT AS A WARM FRONT.
HAVE MORE CLOUD COVER AND COOLER TEMPERATURES NORTH OF THE FRONT
TODAY AND MORE FOG OVERNIGHT TONIGHT. USED A NON DIURNAL TREND FOR
HOURLY TEMPERATURES OVERNIGHT. THOSE LOCATIONS THAT PULL OUT OF
THE WEDGE WILL LIKELY WARM UP AS THEY GET BACK INTO THE WARM
SECTOR.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 330 AM EST SUNDAY...
PRIMARY FOCUS FOR THE SHORT TERM FORECAST WAS ON THE TIMING OF THE
COLD FRONT MOVING THROUGH THE FORECAST AREA LATE MONDAY AND MONDAY
NIGHT. WITH SFC WAVES RIDING UP THE SFC BOUNDARY AND
INITIAL UPPER LEVEL SHORTWAVE LIFTING NORTH WITH MORE
ENERGY DIGGING INTO THE BASE OF THE UPPER LEVEL TROF IN THE CENTRAL
U.S....CONTINUED TO LEAN TOWARD THE SLOWER MODEL SOLUTIONS.
FOR THIS FORECAST PACKAGE...THE SLOWER NAM AND SREF WERE
PREFERRED.
AS WINDS VEER IN RESPONSE TO THE APPROACH OF THE UPPER LEVEL
TROF...SFC WEDGE SHOULD HAVE ERODED BY 12Z MONDAY...OR SHORTLY
THEREAFTER...LEAVING THE ENTIRE FORECAST FIRMLY ENTRENCHED IN THE
WARM SECTOR. A DEEP SOUTHWEST FLOW ALONG WITH SOME BREAKS IN THE
CLOUDS IN THE EAST SHOULD ALLOW TEMPS TO SOAR WELL ABOVE
NORMAL...BUT STILL BELOW RECORDS FOR 12/10.
BEST 850-300MB OMEGA PER THE NAM ARRIVES IN THE WEST AROUND 18Z
MONDAY...BUT LIFTS TO THE NORTH AFTERWARDS WITH UPPER LEVEL
SHORTWAVE. THIS LEAVES UNCERTAINTY ON HOW FAR EAST PRECIPITATION
SHIELD CAN TRAVEL. AS A RESULT...KEPT MUCH HIGHER POPS IN THE
MOUNTAINS...WITH HIGH CHANCE POPS IN THE EAST LATE MONDAY AND MONDAY
NIGHT.
NAM FORECAST SOUNDINGS INDICATE THE LOWER LEVEL OF THE ATMOSPHERE
BEGINS DRYING WHEN TEMPS COLD ENOUGH FOR SNOW BEGINS TO ARRIVE
ALONG THE WESTERN SLOPES. MAY STILL BE ABLE TO SQUEEZE OUT SOME
LIGHT SNOW SHOWERS IN THE HIGHEST ELEVATIONS OF SOUTHEAST
WV/ALLEGHANY HIGHS FOR A FEW HOURS TUESDAY MORNING.
EVEN THE SLOWEST SREF KEEPS SFC BOUNDARY WELL SOUTHEAST OF THE
FORECAST AREA ON TUESDAY. WEAK SFC WAVES MOVING THROUGH EASTERN
NC/VA ON TUESDAY WILL KEEP SOME CLOUDS IN THE FAR EAST...BUT LOW
LEVEL NORTHWEST WINDS WILL KEEP THE FORECAST AREA DRY BY 18Z.
AS SFC RIDGE QUICKLY BUILDS OVER THE AREA TUESDAY...COLD AIR
ADVECTION DIMINISHES DURING THE DAY AND EXPECT TEMPS TO RECOVER AND
USED A BLEND OF THE NAM/GFS MOS GUIDANCE FOR HIGHS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 330 PM EST SATURDAY...
HIGH PRESSURE WILL CONTROL THE WEATHER PATTERN THROUGH FRIDAY. WILL
BE KEEPING AN EYE ON A LOW PRESSURE SYSTEM DEVELOPING ALONG THE
CAROLINA COAST OF WEDNESDAY/THURSDAY TO SEE IF ANY SHOWER ACTIVITY
ADVANCES INTO THE PIEDMONTS...BUT BECOMING MORE CONFIDENT THAT THIS
ACTIVITY WILL STAY EAST OF THE AREA. THE NEXT BIG STORM SYSTEM TO
WATCH WILL ARRIVE NEXT WEEKEND AS A DEEP LOW PRESSURE SYSTEM PASSES
EASTWARD FROM THE CENTRAL PLAINS INTO THE GREAT LAKES...DRAGGING A
COLD FRONT TOWARD OUR AREA.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
AS OF 705 AM EST SUNDAY...
SCATTERED SHOWERS WILL MOVE NORTHEAST AWAY FROM KLWB BY 14Z/9AM
THIS MORNING. COVERAGE OF IFR TO LIFR CEILINGS IS VARIABLE THIS
MORNING. MODERATE CONFIDENCE THAT ANY LOW STRATUS WILL LIFT TO AT
LEAST MVFR LEVELS BY 18Z/1PM.
COLD FRONT WAS OVER NORTHERN VIRGINIA. EXPECT BOUNDARY TO DROP
SOUTH THROUGH THE FOOTHILLS TODAY. IFR TO LIFR CLOUDS NORTH OF THE
FRONT TONIGHT AT LYH AND POSSIBLE ROA. EXPECT MVFR FOG MOST
LOCATIONS AGAIN TONIGHT. DEPENDS ON HOW FAR WEDGE ADVANCES BUT
EVEN KROA MAY HAVE MVFR FOG.
CHANCE OF SHOWERS WILL CONTINUE TODAY WITH MORE WIDESPREAD
PRECIPITATION MOVING INTO THE MOUNTAINS BY MONDAY MORNING. FRONT
LIFTS BACK NORTH EARLY MONDAY THEN VERY STRONG COLD FRONT PUSHES
THROUGH FROM THE WEST MONDAY EVENING.
HAVE ADDED LOW LEVEL WINDS SHEAR TO THE TAFS TONIGHT DUE TO
INCREASING LOW LEVEL JET. MODELS HAVE WINDS JUST ABOVE THE SURFACE
FROM THE SOUTHWEST AT 30 TO 40 KNOTS. EXPECT GUSTY NORTHWEST
WINDS BEHIND THE FRONT ON MONDAY NIGHT AND TUESDAY.
CONDITIONS WILL IMPROVE ON TUESDAY EVENING AS HIGH PRESSURE
BEGINS TO SETTLE ACROSS THE AREA. LINGERING MOISTURE IN THE
MOUNTAINS TUESDAY WILL RESULT IN MVFR CONDITIONS AND THE
POSSIBILITY OF SNOW SHOWERS AS COLDER AIR SURGES INTO THE AREA.
VFR WILL RETURN FOR TUESDAY NIGHT THROUGH FRIDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/NF
SHORT TERM...PH
LONG TERM...NF
AVIATION...AMS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
714 AM EST SUN DEC 9 2012
.SYNOPSIS...
A COLD FRONT FROM NEW ENGLAND TO THE TENNESSEE VALLEY WILL MOVE
SLOWLY SOUTHEAST TODAY BEFORE STALLING AND PUSHING BACK NORTH AS
WARM FRONT TONIGHT. A MUCH STRONGER COLD FRONT WILL CROSS THROUGH
THE AREA FROM THE WEST MONDAY EVENING. COOL HIGH PRESSURE WILL BUILD
IN BEHIND THE FRONT FOR TUESDAY INTO FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 430 AM EST SATURDAY...
SCATTERED TO NUMEROUS SHOWERS...ASSOCIATED WITH A SHORT WAVE
MOVING THROUGH WEST VIRGINIA...WERE TRACKING NORTHEAST ACROSS THE
WESTERN COUNTY WARNING AREA EARLY THIS MORNING. WATER VAPOR LOOP
SHOWED ANOTHER SHORT WAVE JUST ENTERING WESTERN KENTUCKY AND
TENNESSEE WHICH MODELS TAKE ALONG THE SAME TRACK. THIS SHOULD
BRING MORE SHOWERS TO THE WESTERN COUNTY WARNING AREA THIS
AFTERNOON.
SCATTERED SHOWERS WERE ALSO MOVING THROUGH SOUTHSIDE VIRGINIA.
ONCE THESE SHOWERS MOVE THROUGH THIS MORNING THE CHANCE OF
PRECIPITATION WILL BE LOWER IN THIS PART OF THE FORECAST AREA FOR
THE REST OF THE DAY.
THE COLD FRONT EXTENDED FRONT NEW JERSEY TO CENTRAL KENTUCKY.
ONCE THE WEST VIRGINIA SHORT WAVE MOVES SLIGHTLY FARTHER
NORTH...THE FRONT WILL ADVANCE SOUTH INTO THE FOOTHILLS THIS
MORNING. LOCAL WRK AND LATEST RAP SHOWED THE WEDGE REACHING THE
ROANOKE RIVER BY THE END OF THE DAY BEFORE ADVANCING SLOWLY BACK
NORTH TONIGHT.
HAVE MORE CLOUD COVER AND COOLER TEMPERATURES NORTH OF THE FRONT
TODAY AND MORE FOG OVERNIGHT TONIGHT. USED A NON DIURNAL TREND FOR
HOURLY TEMPERATURES OVERNIGHT. THOSE LOCATIONS THAT PULL OUT OF
THE WEDGE WILL LIKELY WARM UP AS THEY GET BACK INTO THE WARM
SECTOR.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 330 AM EST SUNDAY...
PRIMARY FOCUS FOR THE SHORT TERM FORECAST WAS ON THE TIMING OF THE
COLD FRONT MOVING THROUGH THE FORECAST AREA LATE MONDAY AND MONDAY
NIGHT. WITH SFC WAVES RIDING UP THE SFC BOUNDARY AND
INITIAL UPPER LEVEL SHORTWAVE LIFTING NORTH WITH MORE
ENERGY DIGGING INTO THE BASE OF THE UPPER LEVEL TROF IN THE CENTRAL
U.S....CONTINUED TO LEAN TOWARD THE SLOWER MODEL SOLUTIONS.
FOR THIS FORECAST PACKAGE...THE SLOWER NAM AND SREF WERE
PREFERRED.
AS WINDS VEER IN RESPONSE TO THE APPROACH OF THE UPPER LEVEL
TROF...SFC WEDGE SHOULD HAVE ERODED BY 12Z MONDAY...OR SHORTLY
THEREAFTER...LEAVING THE ENTIRE FORECAST FIRMLY ENTRENCHED IN THE
WARM SECTOR. A DEEP SOUTHWEST FLOW ALONG WITH SOME BREAKS IN THE
CLOUDS IN THE EAST SHOULD ALLOW TEMPS TO SOAR WELL ABOVE
NORMAL...BUT STILL BELOW RECORDS FOR 12/10.
BEST 850-300MB OMEGA PER THE NAM ARRIVES IN THE WEST AROUND 18Z
MONDAY...BUT LIFTS TO THE NORTH AFTERWARDS WITH UPPER LEVEL
SHORTWAVE. THIS LEAVES UNCERTAINTY ON HOW FAR EAST PRECIPITATION
SHIELD CAN TRAVEL. AS A RESULT...KEPT MUCH HIGHER POPS IN THE
MOUNTAINS...WITH HIGH CHANCE POPS IN THE EAST LATE MONDAY AND MONDAY
NIGHT.
NAM FORECAST SOUNDINGS INDICATE THE LOWER LEVEL OF THE ATMOSPHERE
BEGINS DRYING WHEN TEMPS COLD ENOUGH FOR SNOW BEGINS TO ARRIVE
ALONG THE WESTERN SLOPES. MAY STILL BE ABLE TO SQUEEZE OUT SOME
LIGHT SNOW SHOWERS IN THE HIGHEST ELEVATIONS OF SOUTHEAST
WV/ALLEGHANY HIGHS FOR A FEW HOURS TUESDAY MORNING.
EVEN THE SLOWEST SREF KEEPS SFC BOUNDARY WELL SOUTHEAST OF THE
FORECAST AREA ON TUESDAY. WEAK SFC WAVES MOVING THROUGH EASTERN
NC/VA ON TUESDAY WILL KEEP SOME CLOUDS IN THE FAR EAST...BUT LOW
LEVEL NORTHWEST WINDS WILL KEEP THE FORECAST AREA DRY BY 18Z.
AS SFC RIDGE QUICKLY BUILDS OVER THE AREA TUESDAY...COLD AIR
ADVECTION DIMINISHES DURING THE DAY AND EXPECT TEMPS TO RECOVER AND
USED A BLEND OF THE NAM/GFS MOS GUIDANCE FOR HIGHS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 330 PM EST SATURDAY...
HIGH PRESSURE WILL CONTROL THE WEATHER PATTERN THROUGH FRIDAY. WILL
BE KEEPING AN EYE ON A LOW PRESSURE SYSTEM DEVELOPING ALONG THE
CAROLINA COAST OF WEDNESDAY/THURSDAY TO SEE IF ANY SHOWER ACTIVITY
ADVANCES INTO THE PIEDMONTS...BUT BECOMING MORE CONFIDENT THAT THIS
ACTIVITY WILL STAY EAST OF THE AREA. THE NEXT BIG STORM SYSTEM TO
WATCH WILL ARRIVE NEXT WEEKEND AS A DEEP LOW PRESSURE SYSTEM PASSES
EASTWARD FROM THE CENTRAL PLAINS INTO THE GREAT LAKES...DRAGGING A
COLD FRONT TOWARD OUR AREA.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 705 AM EST SUNDAY...
SCATTERED SHOWERS WILL MOVE NORTHEAST AWAY FROM KLWB BY 14Z/9AM
THIS MORNING. COVERAGE OF IFR TO LIFR CEILINGS IS VARIABLE THIS
MORNING. MODERATE CONFIDENCE THAT ANY LOW STRATUS WILL LIFT TO AT
LEAST MVFR LEVELS BY 18Z/1PM.
COLD FRONT WAS OVER NORTHERN VIRGINIA. EXPECT BOUNDARY TO DROP
SOUTH THROUGH THE FOOTHILLS TODAY. IFR TO LIFR CLOUDS NORTH OF THE
FRONT TONIGHT AT LYH AND POSSIBLE ROA. EXPECT MVFR FOG MOST
LOCATIONS AGAIN TONIGHT. DEPENDS ON HOW FAR WEDGE ADVANCES BUT
EVEN KROA MAY HAVE MVFR FOG.
CHANCE OF SHOWERS WILL CONTINUE TODAY WITH MORE WIDESPREAD
PRECIPITATION MOVING INTO THE MOUNTAINS BY MONDAY MORNING. FRONT
LIFTS BACK NORTH EARLY MONDAY THEN VERY STRONG COLD FRONT PUSHES
THROUGH FROM THE WEST MONDAY EVENING.
HAVE ADDED LOW LEVEL WINDS SHEAR TO THE TAFS TONIGHT DUE TO
INCREASING LOW LEVEL JET. MODELS HAVE WINDS JUST ABOVE THE SURFACE
FROM THE SOUTHWEST AT 30 TO 40 KNOTS. EXPECT GUSTY NORTHWEST
WINDS BEHIND THE FRONT ON MONDAY NIGHT AND TUESDAY.
CONDITIONS WILL IMPROVE ON TUESDAY EVENING AS HIGH PRESSURE
BEGINS TO SETTLE ACROSS THE AREA. LINGERING MOISTURE IN THE
MOUNTAINS TUESDAY WILL RESULT IN MVFR CONDITIONS AND THE
POSSIBILITY OF SNOW SHOWERS AS COLDER AIR SURGES INTO THE AREA.
VFR WILL RETURN FOR TUESDAY NIGHT THROUGH FRIDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...PH
LONG TERM...NF
AVIATION...AMS
AREA FORECAST DISCUSSION
NWS LINCOLN IL
225 PM CST SUN DEC 9 2012
.DISCUSSION...
ISSUED 210 PM CST SUN DEC 9 2012
SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
COVERAGE OF RAIN ACROSS THE FORECAST AREA EARLY TONIGHT ALONG WITH
TEMPERATURES THE FIRST HALF OF THE UPCOMING WEEK...ARE THE MAIN
FORECAST CONCERNS. USING MORE OF THE NAM-WRF THIS FORECAST PERIOD
ALTHOUGH MODEL DIFFERENCES WERE NEGLIGIBLE.
COLD FRONT IS FORECAST TO PUSH ACROSS THE REGION TONIGHT PUTTING AN
END TO THE RAIN AND BRINGING IN MUCH COLDER WEATHER FOR THE FIRST
HALF OF THE WORK WEEK. THE SNOW ASSOCIATED WITH THE STORM SYSTEM
WILL REMAIN TO OUR NORTH WHILE A SECONDARY BAND OF SHOWERS AND
ISOLATED THUNDERSTORMS WILL ACCOMPANY THE COLD FRONT ACROSS EAST
CENTRAL THRU SOUTHEAST ILLINOIS. THE THUNDER THREAT LOOKS TO BE
QUITE EARLY THIS EVE AND CONFINED ALONG AND SOUTH OF THE I-70
CORRIDOR CLOSER TO THE DEEPER MOISTURE AND BETTER INSTABILITY.
FURTHER TO THE NORTH...FORECAST SOUNDINGS CONTINUE TO INDICATE NOT
MUCH IF ANY ICE PRESENT IN THE UPPER LEVELS OF THE CLOUD...AND IF
THERE WAS ANY...THE LEVELS JUST BELOW IT WERE TOO DRY TO SUPPORT
ANY SNOW THIS EVENING AS THE COLD AIR SWEEPS IN.
ON MONDAY...WITH STRONG CYCLONIC FLOW/LOW LEVEL COLD ADVECTION
INDICATED...ALONG WITH MODELS DEPICTING THE 850 MB THERMAL TROF
PUSHING THRU THE AREA DURING THE LATE MORNING AND EARLY AFTN
HOURS...WE SHOULD SEE PLENTY OF CLOUD COVER AND GUSTY NORTHWEST
WINDS...ALONG WITH SOME FLURRIES...ESP ACRS THE NORTH AND EAST.
THE NAM-WRF AND GFS INDICATES A 500 MB VORT TROF TO SHIFT THRU
THE AREA AS WELL DURING THE AFTN ACCOMPANIED BY SOME COLD TEMPS
ALOFT. FORECAST SOUNDINGS SHOWING SOME DECENT LOW AND MID LEVEL
LAPSE RATES ALONG WITH MORE MOISTURE ABOVE 850 MB THAN PREVIOUS
MODELS FORECAST SO WILL HAVE AT LEAST A CHANCE FOR FLURRIES MAINLY
ACRS THE NORTH AND EAST DURING THE DAY. 500 MB TROF AXIS SHOULD
EXIT TO OUR EAST LATE MONDAY AFTERNOON TAKING ANY FLURRY THREAT
WITH IT. WE SHOULD THEN SEE A DECREASE IN CLOUDS AND WINDS DURING
THE EVENING WITH THE NAM SHOWING THE SURFACE RIDGE AXIS RIGHT OVER
THE FORECAST AREA BY 12Z TUESDAY. AFTER A COLD START TUESDAY MORNING
WE SHOULD SEE A RATHER QUIET WEATHER PATTERN OVER THE MIDWEST THRU
WEDNESDAY NIGHT AS UPPER LEVEL HEIGHTS BUILD OVER THE CENTER OF THE
NATION AS A DEEP TROF DIGS INTO THE ROCKIES.
LONG TERM...THURSDAY THROUGH SUNDAY
THE UPPER FLOW ACROSS THE MIDWEST BECOMES SOUTHWESTERLY AS THE
AFOREMENTIONED TROF SETS UP OVER THE ROCKIES LATE IN THE WEEK. THIS
SHOULD BRING WARMER TEMPERATURES INTO OUR AREA WITH DRY CONDITIONS
HOLDING THRU FRIDAY. THE LATEST OPERATIONAL GFS HAS MADE A SIGNIFICANT
CHANGE FROM ITS PREVIOUS RUNS WITH RESPECT TO THE LATE FRIDAY/SATURDAY
WEATHER SYSTEM IN TAKING TWO SEPARATE SYSTEMS ACROSS THE MIDWEST
RATHER THAN ONE LARGE LOW AT THE SURFACE AND AT 500 MB...WHICH THE
12Z ECMWF CONTINUES TO INDICATE. WILL CONTINUE TO SIDE WITH THE MORE
CONSISTENT ECMWF SOLUTION IN BRINGING RAIN CHANCES INTO OUR AREA
FRIDAY NIGHT AND CONTINUING AT LEAST A CHANCE OF RAIN ON SATURDAY.
THE ECMWF HAS TRENDED A BIT SLOWER WITH ITS TRACK ACRS THE MIDWEST
ON SATURDAY SO WILL KEEP AT LEAST SLIGHT CHANCES GOING INTO SATURDAY
EVENING OVER THE EASTERN TWO-THIRDS OF THE FORECAST AREA.
ACTIVE PATTERN SHOULD HOLD AFTER OUR WEEKEND SYSTEM MOVES OUT AS ANOTHER
STRONG UPPER WAVE IS FORECAST TO GET EJECTED ENE OUT OF THE MEAN
LONGWAVE TROF POSITION OVER THE ROCKIES. THIS SHOULD BRING ANOTHER
STORM SYSTEM NORTHEAST INTO THE MIDWEST...ALTHOUGH THE LATEST ECMWF
IS INDICATING THE STRONGEST CORE OF WINDS AT 250 MB STILL ON THE WEST
SIDE OF THE TROF LATE NEXT WEEKEND...SUGGESTING THIS WAVE MAY DIG MORE
THAN ITS PREDECESSOR AND TAKE A MORE SOUTHERLY TRACK. ANY WEATHER
ASSOCIATED WITH THIS SHORTWAVE WILL OCCUR BEYOND THIS FORECAST PERIOD.
WITH THE UPPER FLOW FORECAST TO REMAIN SOUTHWEST THRU NEXT WEEKEND...
NO SIGNS OF ANY SIGNIFICANT BUCKLING OF THE JET TO ALLOW A PROLONGED
PERIOD OF COLD INTO THE MIDWEST...OTHER THAN THE BRIEF COOL OFFS BEHIND
THESE SOUTHWEST SYSTEMS.
SMITH
&&
.AVIATION...
ISSUED 1059 AM CST SUN DEC 9 2012
CEILINGS REMAIN THE PRIMARY CONCERN FOR THIS TAF SET. CENTRAL
ILLINOIS TAF SITES CURRENTLY AROUND 300-400 FEET...WITH VISIBILITY
OF 1 TO 2SM. SOME MODEST IMPROVEMENTS EXPECTED AFTER A FRONTAL
BOUNDARY CURRENTLY IN EASTERN MISSOURI PUSHES THROUGH OUR AREA...
GENERALLY CROSSING THE TAF SITES IN THE 19-22Z TIME FRAME. VISIBLE
SATELLITE IMAGERY SHOWING A CLEARING LINE EXTENDING NORTH AND
SOUTHWEST FROM KANSAS CITY. AWIPS TIME-OF-ARRIVAL TOOL WOULD PLACE
IT AROUND KPIA/KSPI TOWARD 23Z IF IT HOLDS TOGETHER...HOWEVER THE
LOW LEVEL HUMIDITY PLOTS OFF THE RAP AND NAM MODELS SUGGEST ONLY
SOME TEMPORARY BREAKS IN THE CEILING BY THAT POINT...SO WILL
MAINTAIN MVFR CEILINGS FOR NOW. CIRCULATION AROUND THE DEPARTING
STORM SYSTEM EXPECTED TO BRING ANOTHER SLUG OF STRATOCUMULUS
OVERNIGHT...PERSISTING MUCH OF THE MORNING...WITH CEILINGS
REMAINING BELOW 3000 FEET THROUGH MONDAY MORNING.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1115 AM CST SUN DEC 9 2012
.DISCUSSION...
ISSUED 1000 AM CST SUN DEC 9 2012
FIRST WAVE OF PRECIPITATION HAS LARGELY LIFTED OUT OF THE FORECAST
AREA...WITH SOME RESIDUAL SHOWERS/DRIZZLE LINGERING...ESPECIALLY
ACROSS THE NORTH. SHOWERS AND SCATTERED THUNDERSTORMS ACROSS
SOUTHERN MISSOURI EXPECTED TO FOLLOW A WAVE OF ENERGY LIFTING
NORTHEAST OUT OF NORTHERN ARKANSAS...AND WILL POSE A THREAT TO
AREAS SOUTH OF I-70 BY EARLY AFTERNOON. THE REMAINDER OF THE
FORECAST AREA WILL ONLY SEE SCATTERED SHOWERS DURING THE AFTERNOON
HOURS.
HAVE UPDATED THE ZONES/GRIDS FOR THE LATEST RAIN TRENDS. TEMPERATURES
WERE LARGELY IN GOOD SHAPE AND NEEDED LITTLE MODIFICATION.
GEELHART
&&
.AVIATION...
ISSUED 1059 AM CST SUN DEC 9 2012
CEILINGS REMAIN THE PRIMARY CONCERN FOR THIS TAF SET. CENTRAL
ILLINOIS TAF SITES CURRENTLY AROUND 300-400 FEET...WITH VISIBILITY
OF 1 TO 2SM. SOME MODEST IMPROVEMENTS EXPECTED AFTER A FRONTAL
BOUNDARY CURRENTLY IN EASTERN MISSOURI PUSHES THROUGH OUR AREA...
GENERALLY CROSSING THE TAF SITES IN THE 19-22Z TIME FRAME. VISIBLE
SATELLITE IMAGERY SHOWING A CLEARING LINE EXTENDING NORTH AND
SOUTHWEST FROM KANSAS CITY. AWIPS TIME-OF-ARRIVAL TOOL WOULD PLACE
IT AROUND KPIA/KSPI TOWARD 23Z IF IT HOLDS TOGETHER...HOWEVER THE
LOW LEVEL HUMIDITY PLOTS OFF THE RAP AND NAM MODELS SUGGEST ONLY
SOME TEMPORARY BREAKS IN THE CEILING BY THAT POINT...SO WILL
MAINTAIN MVFR CEILINGS FOR NOW. CIRCULATION AROUND THE DEPARTING
STORM SYSTEM EXPECTED TO BRING ANOTHER SLUG OF STRATOCUMULUS
OVERNIGHT...PERSISTING MUCH OF THE MORNING...WITH CEILINGS
REMAINING BELOW 3000 FEET THROUGH MONDAY MORNING.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 245 AM CST SUN DEC 9 2012
SHORT TERM...TODAY THROUGH TUESDAY
LOW PRESSURE CURRENTLY OVER OKLAHOMA WILL TRACK NORTHEASTWARD
TODAY...EVENTUALLY REACHING CENTRAL INDIANA BY EARLY EVENING. THIS
PARTICULAR TRACK WILL KEEP MUCH OF THE KILX CWA ON THE COOL SIDE
OF THE SYSTEM...WHILE AREAS ALONG/SOUTH OF THE I-70 CORRIDOR PUNCH
INTO THE WARM SECTOR DURING THE AFTERNOON. ISENTROPIC UPGLIDE NOTED
ON THE 295K SURFACE WILL BECOME NEUTRAL AS THE WEAK LOW PRESSURE
CENTER MOVES INTO THE VICINITY TOWARD MIDDAY. AS A RESULT...THINK
SHOWERS WILL BE MOST WIDESPREAD THROUGH 15Z/9AM...BEFORE MAIN PRECIP
AREA SHIFTS FURTHER NORTHEAST. WILL THEREFORE CARRY CATEGORICAL
POPS THIS MORNING...THEN JUST CHANCE POPS ACROSS MUCH OF THE AREA
THIS AFTERNOON. THE EXCEPTION WILL BE ALONG/SOUTH OF I-70...WHERE
MODELS TRY TO DEVELOP ADDITIONAL SHOWERS IN THE WARM SECTOR LATER
IN THE DAY. MAY EVEN BE A FEW ISOLATED THUNDERSTORMS ACROSS THE
FAR SE CWA...COURTESY OF DEWPOINTS IN THE LOWER 50S AND LIFTED
INDEX VALUES APPROACHING 0C. HIGH TEMPERATURES WILL BE QUITE
VARIABLE TODAY...RANGING FROM THE MIDDLE 40S IN THE ILLINOIS RIVER
VALLEY...TO THE LOWER 60S SOUTH OF I-70.
AS LOW TRACKS INTO CENTRAL INDIANA...WINDS WILL SWITCH TO THE
NORTHWEST...ALLOWING A MUCH COLDER AIR MASS TO FILTER INTO THE AREA
TONIGHT. 00Z DEC 9 MODELS ARE NOW INDICATING THAT THE COLD AIR
WILL LAG BEHIND THE DEPARTING MOISTURE JUST ENOUGH TO PREVENT ANY
CHANGE OVER FROM LIGHT RAIN SHOWERS TO SNOW SHOWERS. WILL LINGER A
FEW RAIN SHOWERS THROUGH THE EVENING EAST OF I-55...THEN WILL GO
MAINLY DRY OVERNIGHT. LOW TEMPERATURES WILL RANGE FROM THE LOWER
20S AROUND GALESBURG...TO THE MIDDLE 30S NEAR LAWRENCEVILLE.
BELOW NORMAL TEMPS WILL TAKE HOLD ACROSS THE MIDWEST FOR MONDAY
AND TUESDAY...AS CANADIAN HIGH PRESSURE DOMINATES THE WEATHER.
HIGHS BOTH DAY WILL REMAIN IN THE 30S...WHILE LOWS DIP INTO THE
TEENS MONDAY NIGHT.
LONG TERM...WEDNESDAY THROUGH SATURDAY
UPPER TROUGHING WILL RELAX BY MID-WEEK...FOLLOWED BY A RETURN TO
ZONAL FLOW. END RESULT WILL BE MODERATING TEMPERATURES THROUGH THE
BALANCE OF THE WEEK...WITH HIGHS CLIMBING INTO THE UPPER 40S AND
LOWER 50S BY FRIDAY AND SATURDAY. BOTH THE ECMWF AND GFS MAINTAIN
DRY CONDITIONS THROUGH FRIDAY...BUT THEN BRING NEXT SIGNIFICANT
SHORT-WAVE INTO THE REGION OVER THE WEEKEND. GIVEN GOOD MODEL
AGREEMENT...WILL CARRY HIGH CHANCE POPS FOR RAIN FRIDAY NIGHT INTO
SATURDAY.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
310 PM CST SUN DEC 9 2012
.DISCUSSION...
20Z WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL TROUGH FROM THE FOUR
CORNERS REGION INTO THE DAKOTAS. ONE SHORTWAVE WAS LIFTING
NORTHEAST INTO MN WITH ANOTHER SHORTWAVE OVER THE CO AND NM
ROCKIES. AT THE SURFACE...A VERY STRONG COLD FRONT HAS PUSHED
SOUTH INTO NORTH TX AND EAST INTO CENTRAL MO. AREA OBSERVATIONS
INDICATE STRONG COLD AND DRY AIR ADVECTION IS ONGOING. RADAR
TRENDS THROUGHOUT THE DAY HAVE SUPPORTED THE IDEA THAT THE DRY AIR
NEAR THE SURFACE IS TO MUCH FOR WEAK FRONTOGENESIS IN THE MID
LEVELS TO OVERCOME.
FOR TONIGHT AND MONDAY...MODELS SHOW LITTLE OR NO LARGE SCALE
FORCING THROUGH THE PERIOD WITH THE ONLY INDICATION OF FORCING FOR
PRECIP BEING WEAK MID LEVEL FRONTOGENESIS THROUGH THE EARLY EVENING.
GIVEN THE CONTINUED ADVECTION OF DRY AIR IN THE LOWER TROPOSPHERE...
THINK PRECIP CHANCES ARE PRETTY CLOSE TO NIL. BY MONDAY...THE COLD
SURFACE RIDGE OF HIGH PRESSURE WITH VERY DRY AIR IS EXPECTED TO
DOMINATE THE WEATHER AS THE SHORTWAVE OVER THE SOUTHERN ROCKIES
PASSES MAINLY TO THE SOUTH OF THE FORECAST AREA. THEREFORE THE
FORECAST WILL REMAIN DRY. ABOUT THE ONLY WEATHER CONCERN IS CLOUD
COVER OVERNIGHT. VISIBLE SATELLITE SHOWS AN AREA OF STRATOCU MOVING
SWIFTLY SOUTH ACROSS EASTERN NEB. THE RAP SHOWS THIS DECK OF LOW
CLOUDS HANGING IN ACROSS NORTHEAST AND EAST CENTRAL KS THROUGH MUCH
OF THE NIGHT...AND THE NAM AND GFS TO A LESSER EXTENT SUPPORT THE
IDEA. SO THINK SKIES WILL BE MOSTLY CLOUDY TONIGHT. BECAUSE OF THIS
HAVE KEPT LOWS A DEGREE OR TWO WARMER THAN THE MOS GUIDANCE ACROSS
EASTERN KS. ADDITIONALLY A STRONGLY MIXED BOUNDARY LAYER SHOULD HELP
KEEP LOWS FROM PLUMMETING. NORTH CENTRAL KS COULD SEE SINGLE DIGIT
LOWS WHERE SKIES SHOULD CLEAR OUT SOONER. WITH SUCH A COLD START TO
THE DAY...HIGHS ARE EXPECTED TO ONLY MAKE IT INTO THE LOWER AND MID
30S FOR MONDAY EVEN WITH MOSTLY SUNNY SKIES.
WOLTERS
MID WEEK PERIODS LOOKING RATHER BENIGN. SOME MID AND HIGH CLOUDS
SHOULD BE ALL THAT RESULTS FROM THE NEXT UPPER WAVE PASSING THROUGH
THE CENTRAL PLAINS MONDAY NIGHT INTO EARLY TUESDAY. LOW LEVEL FLOW
REMAINS MAINLY WESTERLY TUESDAY FOR WEAK WARM AIR ADVECTION...AND
WAA INCREASES INTO WEDNESDAY AND THURSDAY AS BROAD RIDGING OVERTAKES
THE CENTRAL AND EASTERN CONUS. THE DEGREE OF MIXING INTO THE WARM
AND DRY MID LEVELS IS THE MAIN QUESTION FOR HOW WARM HIGHS WILL GET.
BUMPED THEM UP A FEW DEGREES AT THIS POINT BUT FURTHER INCREASES MAY
BE NEEDED. SSW WINDS INCREASE FOR WEDNESDAY INTO THURSDAY AND
RELATIVE HUMIDITIES MAY DROP TO LEVELS OF SOME CONCERN FOR FIRE
WEATHER MAINLY ON WEDNESDAY.
MEDIUM RANGE MODELS ARE IN DECENT AGREEMENT WITH WESTERN TROF AND
UPPER LOW IN THE SOUTHWEST CONUS ON THURSDAY...BUT DIFFERENCES
MAGNIFY QUICKLY INTO THE WEEKEND. THE 12Z ECMWF PUSHES THE LOW EAST
AHEAD OF THE NORTHERN TROF AND ALLOWS A LOW TO RE-CLOSE AND DEEPEN
RAPIDLY OVER THE CENTRAL PLAINS...WHILE THE 12Z GFS KEEPS THE
SOUTHERN LOW BEHIND THE NORTHERN TROF FOR A WEAKENING WAVE IN THE
PLAINS. MODERATE PRECIPITATION CHANCES REMAIN...CENTERED AROUND
FRIDAY NIGHT...WITH SOME OPPORTUNITY FOR CONVECTION IN THE MORE
AMPLIFIED SOLUTIONS AND MINOR CONCERN FOR WINTRY PRECIP AS THE EVENT
WINDS DOWN. TEMPS SHOULD RETURN TO NEAR MID-DECEMBER NORMALS FOR
SUNDAY.
65
&&
.AVIATION...
LATEST OBS AND RADAR SHOWING LOW LEVEL DRY AIR WINNING OUT OVER THE
WEAK FORCING...AND MODELS SHOW THESE CONDITIONS PERSISTING THROUGH
THE AFTERNOON. THERE IS ONE LITTLE PATCH OF STRATOCU SEEN ON
SATELLITE NEAR TOP AND FOE WHICH WILL BE OUT SHORTLY. OTHERWISE VFR
CONDITIONS SHOULD PREVAIL INTO THE EARLY EVENING. MODELS DO HINT AT
SOME MVFR CIGS MOVING SOUTH THROUGH EASTERN NEB OVERNIGHT. THEREFORE
HAVE CONTINUED THE PREV FORECAST OF CIGS BETWEEN 2 AND 3 KFT
OVERNIGHT. WINDS WILL REMAIN UP DUE TO A STRONG PRESSURE GRADIENT.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1205 PM CST SUN DEC 9 2012
.UPDATE...
FALLING TEMPERATURES ARE ANTICIPATED THROUGH THE AFTERNOON HOURS ACROSS
MUCH OF CENTRAL AND SOUTHEAST KANSAS WITHIN STRONG LOW-LEVEL CAA POST-
FRONTAL REGIME. WINDS MAY FLIRT WITH ADVISORY CRITERIA BRIEFLY...ESPECIALLY
ACROSS CENTRAL KANSAS HOWEVER DUE TO THE SHORT DURATION NO
HEADLINES ARE ANTICIPATED. VERY DRY IS ALSO BEING ADVECTED THROUGH
THE PBL DECREASING THE PROBABILITY FOR SEEING ANY SNOW FLURRIES SO
MAINTAINED A DRY FORECAST THROUGH THE OVERNIGHT PERIOD.
MWM
&&
.AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
NORTHWEST WINDS AROUND 25 KNOTS WITH GUSTS INTO THE 30-35 KNOT
RANGE ARE EXPECTED BEHIND A STRONG COLD FRONT. THE WINDS WILL
LIKELY STAY UP INTO THE EVENING HOURS BEFORE DIMINISHING TOWARD
MORNING. MID CLOUDS IN THE 7-10K FT RANGE WILL GRADUALLY CLEAR
OVERNIGHT WITHIN A VERY DRY AND SUBSIDENT AIRMASS BUILDING INTO
THE AREA.
&&
.PREV DISCUSSION... /ISSUED 527 AM CST SUN DEC 9 2012/
AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
THE MAIN AVIATION FORECAST CONCERN IS LIFR/IFR CONDITIONS AHEAD OF
THE FRONT AND THEN STRONG GUSTY WINDS BEHIND THE FRONT TODAY.
THE COLD FRONT IS THROUGH MUCH OF KANSAS...BUT THE STRONGER WINDS
ARE JUST REACHING KRSL AS OF 11Z. WINDS WILL ONLY CONTINUE TO GET
STRONGER THROUGHOUT THE DAY WITH 20-25 KTS GUSTING TO 30-35
EXPECTED ACROSS ALL TERMINALS TODAY. WINDS WILL DECREASE
SOME...BUT STAY BREEZY OVERNIGHT.
AHEAD OF THE FRONT LIFR AND IFR CONDITIONS DOMINATE UNDER LOW
STRATUS. AS THE DRIER/COOLER AIR MOVES IN BEHIND THE FRONT...LOW
STRATUS IS SCATTERING OUT WITH A MID LEVEL CLOUD DECK OVERHEAD.
HAVE REMAINED PESSIMISTIC WITH THE FORECAST AT SITES THAT ARE
AHEAD OF THE FRONT...KICT/KCNU KEEPING THEM IN LIFR UNTIL THE
EXPECTED FRONTAL PASSAGE...ALTHOUGH IT MAY BE OFF AND ON WITH
RAGGED CEILINGS ACROSS THE AREA. SKIES WILL BEGIN TO CLEAR
OVERNIGHT FROM KRSL TO KICT UNDER HIGH PRESSURE.
WHILE THERE IS STILL A HINT OF SOME PRECIPITATION WITH THIS
SYSTEM...CONFIDENCE IS LOW THAT ANY WILL ACTUALLY REACH THE
GROUND. THERE IS DECENT LIFT IN THE MID-LEVELS...BUT THE LOWEST
8-12 KFT ARE VERY DRY AND WOULD EXPECT ANY PRECIPITATION THAT DOES
FALL TO EVAPORATE. THAT BEING SAID...CANNOT RULE OUT SOME DRIZZLE
AHEAD OF THE FRONT...AND SOME FLURRIES BEHIND THE FRONT. DID LEAVE
MENTION OF FLURRIES OUT OF THE FORECAST AT ALL TERMINALS BECAUSE
OF THIS. ANY ACTIVITY THAT DOES OCCUR WILL NOT REDUCE
VISIBILITIES.
BILLINGS
PREV DISCUSSION... /ISSUED 329 AM CST SUN DEC 9 2012/
DISCUSSION...
TODAY-THIS EVENING:
THE GUSTY NORTHWEST WINDS AND COLDEST AIR IS LAGGING BEHIND THE
INITIAL WIND SHIFT. PRECIPITATION SO FAR HAS BEEN EXTREMELY LIMITED
AND BASED ON LATEST MODEL RUNS...LOW LEVEL DRY AIR WILL LIKELY BE
TOUGH TO OVERCOME. HOWEVER BEST SATURATION/LIFT IN TRAILING BAND
FAIRLY IMPRESSIVE...BUT SO IS THE 10KFT OF DRY AIR BELOW IT. WHILE
LIGHT SNOW IS LIKELY ALOFT...BELIEVE IT WILL BE VERY DIFFICULT TO
GET MORE THAN SCATTERED FLURRIES TO THE GROUND. MID/UPPER LEVEL LIFT
ACTUALLY INCREASES A BIT TOWARDS 0000 UTC...AND WILL LINGER
FLURRIES UNTIL MIDNIGHT ACROSS EASTERN SECTIONS. TEMPERATURES WILL
GENERALLY FALL THROUGHOUT THE DAY WITH COLD AIR ADVECTION FROM THE
GUSTY NORTHWEST WINDS.
LATE TONIGHT:
TEMPERATURES WILL CONTINUE TO TUMBLE DURING THE NIGHT WITH CLEARING
SKIES AND DECREASING WINDS. MODEL OUTPUT STATISTICS GUIDANCE IN
GOOD AGREEMENT FOR SINGLE DIGITS FOR FAR NORTHWEST SECTIONS.
MON-SAT:
AFTER VERY CHILLY START TO MONDAY...EXPECT A GRADUAL MODERATION OF
THE COLD AIRMASS. SHORTWAVE MOVING THROUGH MIDWEEK STILL APPEARS TO
BE MOISTURE STARVED WITH ONLY SOME INCREASE IN CLOUDS. DECENT
WARMUP ANTICIPATED WITH COMBINATION OF DRY AIR AND FAVORABLE SW
FLOW AT H85 ON THU. MODELS HAVE DIVERGED WITH TRACK/TIMING OF
SYSTEM LATE IN THE WEEK. UNFORTUNATELY...OVERALL TREND HAS LOWER
CHANCES FOR PRECIPITATION ACROSS WESTERN HALF OF FORECAST AREA AS
SURFACE CYCLOGENSIS DEVELOPS DRY SLOT OVER MUCH OF THE FORECAST
AREA. BEST CHANCE STILL APPEARS TO BE IN SOUTHEAST KS. -HOWERTON
AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
LOW LEVEL ISENTROPIC LIFT FROM THE SOUTH-SOUTHWEST HAS LED TO
WIDESPREAD IFR CONDITIONS ACROSS THE REGION LATE THIS EVENING. BOTH
THE NAM/WRF AND GFS NOT HANDLING THIS LOW LEVEL MOISTURE VERY
WELL...WITH THE LATEST RUC40 CLOSER TO REALITY. THE CEILINGS EVEN
DROPPED LOWER THAN THE PESSIMISTIC RUC ON CEILINGS TO AROUND 6-9K FT
AGL.
EXPECT THE IFR CONDITIONS TO BE SHORT LIVED...AS A COLD FRONTAL
BOUNDARY LOOKS TO ARRIVE AFTER 08Z-09/SUN ACROSS CENTRAL
KANSAS...AND PLUNGE SOUTH ACROSS SOUTH CENTRAL KS AFTER 09-11Z/SUN.
THIS WILL LEAD TO CEILINGS BEGINNING TO RAPIDLY LIFT WITH MVFR/VFR
CEILINGS RETURNING BY THE MORNING HOURS ON SUN...AS LOW LEVELS
QUICKLY DRY OUT. WINDS BEHIND THE FRONT WILL INCREASE TO 20-30 KTS
WITH SOME LIGHT SNOW DEVELOPING ACROSS PORTIONS OF CENTRAL KANSAS
EARLY SUNDAY. NOT EXPECTING THE LIGHT SNOW TO RESTRICT VSBYS MUCH
WITH VFR CONDITIONS EXPECTED...AS THIS WILL BE MAINLY A LIGHT
SNOW/FLURRY EVENT.
KETCHAM
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 41 12 37 19 / 10 10 0 0
HUTCHINSON 37 11 37 21 / 10 10 0 0
NEWTON 37 12 35 20 / 10 10 0 0
ELDORADO 40 13 35 18 / 10 10 0 0
WINFIELD-KWLD 42 14 37 21 / 10 10 0 0
RUSSELL 35 4 37 19 / 10 0 0 0
GREAT BEND 34 7 37 22 / 20 0 0 0
SALINA 36 9 37 20 / 10 10 0 0
MCPHERSON 36 11 37 20 / 10 10 0 0
COFFEYVILLE 47 18 36 19 / 20 10 0 0
CHANUTE 44 14 34 18 / 20 10 0 0
IOLA 43 14 34 20 / 20 10 0 0
PARSONS-KPPF 45 17 35 16 / 20 10 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
546 PM EST SUN DEC 9 2012
.SYNOPSIS...
A SURFACE LOW WILL PUSH NORTHEAST INTO THE OHIO VALLEY THIS
EVENING AND LIFT A WARM FRONT INTO THE REGION. THIS WILL ALLOW
FOR SHOWERS TO MOVE ACROSS THE AREA AND CONTINUE INTO MONDAY. A COLD
FRONT WILL CROSS THE AREA ON MONDAY...ALLOWING FOR A CHANGE OVER
TO SNOW SHOWERS MONDAY NIGHT WITH A MUCH COOLER AIR MASS BUILDING
INTO THE AREA FOR THE MID-WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
A BRIEF INTERLUDE SEEMS LIKELY TO ENSUE BETWEEN THE MAINLY PRE-
WARM FRONTAL ISENTROPIC STRATIFORM PRECIPITATION AND THE WARM
SECTOR CONVECTIVE PRECIPITATION THIS EVENING FOR MANY SECTIONS OF
THE FORECAST AREA. HOWEVER...WITH THE NORTHWARD MIGRATION OF THE
WARM FRONT...MID-LEVEL INSTABILITY DOES INCREASE ALL THE WHILE
SYNOPTIC FORCING VIA UPPER DIVERGENCE FROM A NEARING AND SLIGHTLY
ANTI-CYCLONICALLY CURVED RIGHT ENTRANCE OF AN UPPER JET STREAK
COMES INTO PLAY. THE CURVATURE OF THIS JET STREAK SHOULD HELP TO
GIVE ADDITIONAL AGEOSTROPHIC ENHANCEMENT OF UPPER DIVERGENCE
FIELD AND THEREBY YIELD MORE STRONGLY NEGATIVE OMEGAS. THIS
COUPLED WITH THE DOWNFLOW TRAJECTORY OF MID-LEVEL FORCING VIA
IMPRESSIVE FRONTOGENESIS AND DIFFERENTIAL PVA AS WELL AS A FAIRLY
LOW PENETRATING PV ANOMALY ON THE MODEL CONSENSUS THAT TRACKS A
WEAK TROPOPAUSE FOLD FROM MISSOURI INTO NORTHERN OHIO THROUGH
MONDAY WOULD FAVOR A SWATH OF HEAVIER RAINFALL JUST AHEAD OF SAID
CORRIDOR. THIS WEAK FOLD IS LIKELY RESPONSIBLE FOR THE STRONG MID-
LEVEL FRONTOGENESIS NOTED ON THE MODELS.
GIVEN SAID SETUP...QPF GRIDS WERE INCREASED PRIMARILY FROM
ZANESVILLE TO MERCER COUNTY OR SO. THE MODEL CONSENSUS FAVORS THIS
FARTHER WEST QPF AXIS...WHILE THE GFS PREFERS A FARTHER EAST
PLACEMENT. HOWEVER...GIVEN THE TRACK OF THE UPPER LEVEL
FIELDS...THE GFS POSITIONING FAILS THE SANITY TEST AT THIS TIME.
OTHER THAN MAINLY QPF AND SLIGHT POP ADJUSTMENTS THIS
EVENING...THE REST OF THE FORECAST FEATURES STEADY/RISING
TEMPERATURES WITH THE NORTHWARD SLOSH OF THE WARM FRONT STILL
SEEMS ON TRACK. FRIES
PREVIOUS DISCUSSION FOLLOWS...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A TROUGH MOVING FROM
THE NORTHERN PLAINS INTO THE UPPER MIDWEST WITH THE UPPER OHIO
VALLEY IN A SOUTHWESTERLY FLOW WELL AHEAD OF THIS FEATURE. AT THE
SURFACE...THERE ARE TWO LOWS WELL UPSTREAM...ONE MOVING ACROSS THE
UPPER MIDWEST AND ANOTHER ACROSS THE MISSOURI VALLEY. THE FRONTAL
BOUNDARY BETWEEN THESE TWO LOWS IS THE DEMARCATION BETWEEN A WARM
AND MOIST AIR MASS AHEAD OF IT AND ARCTIC AIR BUILDING IN BEHIND
IT. A WARM FRONT EXTENDS NORTHEASTWARD FROM THE SOUTHERN LOW
ACROSS SOUTHERN OHIO AND INTO CENTRAL WV. LOCALLY...THE NEXT WAVE
IS RIDING ALONG AND NORTH OF THE WARM FRONT AND DEVELOPING AS IT
PUSHES INTO EASTERN OHIO AND NORTH-CENTRAL WV.
THIS EVENING...THE SURFACE LOW ACROSS THE MISSOURI VALLEY WILL
QUICKLY LIFT INTO THE OHIO VALLEY...MERGING WITH THE LOW IN THE UPPER
MIDWEST AND PULLING THE WARM FRONT NORTHWARD INTO THE UPPER OHIO
VALLEY. THE AREA OF SHOWERS ASSOCIATED WITH THE SHORT WAVE IS CURRENTLY
MOVING INTO THE AREA WILL SLIDE NORTHEASTWARD WITH THE WARM FRONT
AND PUSH INTO WESTERN PA. MESOSCALE MODELS ARE SUPPORTIVE OF THIS
FEATURE MOVING THROUGH MOST OF THE AREA BY LATE EVENING...AND THUS
POPS INCREASE TO CATEGORICAL.
TEMPS WILL BE SUBJECT TO THE NORTHWARD PROGRESSION OF THE WARM
FRONT. LAMP/WRF-NMM SUGGEST TEMPS WILL BE SLOW TO WARM WITH A WARM
SURGE OCCURRING AND HIGH TEMPS OCCURRING AFTER 21Z.
TONIGHT...THE MERGED SURFACE LOW WILL CROSS THE OHIO VALLEY AND PUSH
INTO THE EASTERN GREAT LAKES. ITS WARM FRONT WILL SHIFT NORTHEAST
OF THE AREA AND A COLD FRONT AND ITS ASSOCIATED SURFACE TROUGH
WILL BEGIN TO APPROACH FROM THE WEST. BETWEEN WARM FRONTAL SHOWERS
AND SHOWERS AHEAD OF THE COLD FRONT MOVING IN FROM THE
WEST...CATEGORICAL POPS ARE FORECAST THROUGH MUCH OF THE
OVERNIGHT. TEMPS WILL REMAIN INCREASE A FEW DEGREES OVERNIGHT IN
WAA...WITH LOWS RANGING FROM THE MID 50S IN NORTH- CENTRAL WV TO
THE LOWER 30S NORTH OF THE I-80 CORRIDOR.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
GFS/NAM/ECMWF ARE IN AGREEMENT THAT THE MID-LEVEL TROUGH WILL
DE-AMPLIFY AS IS SLIDES EASTWARD ACROSS THE GREAT LAKES AND PUSHES A
COLD FRONT ACROSS THE UPPER OHIO VALLEY ON MONDAY. A MODEL CONSENSUS
OF THE EQUIVALENT POTENTIAL TEMPERATURE GRADIENT INDICATES A COLD
FRONT JUST NORTHWEST OF THE PITTSBURGH METRO AROUND 18Z ON MONDAY.
AHEAD OF THE FRONT...H5 VORTICITY INDICATES ENERGY IN WAA THAT WILL
ALLOW FOR SCATTERED SHOWERS AHEAD OF THE FRONT. A WELL-DEFINED
SURFACE TROUGH ASSOCIATED WITH THE COLD FRONT ALONG WITH THE STRONG
THERMAL GRADIENT ALONG THE FRONT WILL ALSO PROVIDE SUFFICIENT
FORCING FOR SHOWERS ALONG AND BEHIND THE FRONT. WITH THIS IN
MIND...CATEGORICAL POPS ARE FORECAST ACROSS THE MAJORITY OF THE AREA
THROUGH 21Z. WITH THE STRENGTH OF THE FRONT...VERY WEAK
INSTABILITY...AND STRONG SHEAR IN PLACE...HAVE INCLUDED A SCHC
THUNDER MENTION LATE MONDAY MORNING INTO THE EARLY AFTERNOON.
AHEAD OF THE FRONT...ONGOING WAA WILL ALLOW TEMPS TO BE IN THE UPPER
50S ACROSS MANY LOCATIONS WITH EVEN TEMPS NEAR 60 POSSIBLE IN
NORTH-CENTRAL WV.
CAA WILL ENSUE ACROSS THE ENTIRE AREA BY 00Z TUESDAY AS THE FRONT
SHIFTS SOUTHEAST OF THE AREA. WITH STRONG CAA...850MB TEMPS WILL
COOL TO AROUND 6-8C BY 12Z TUESDAY. 1000-500MB THICKNESS LINE DROPS
SOUTHEASTWARD QUICKLY OVERNIGHT AND IN RETURN...ANY LINGERING RAIN
SHOWERS WILL TURN TO SNOW SHOWERS BEHIND THE FRONT. SNOW
ACCUMULATION WILL BE LIGHT...WITH A DUSTING IN MOST LOWLAND
LOCATIONS AND UP TO AN INCH POSSIBLE ACROSS THE EASTERN RIDGES. LOWS
ON MONDAY NIGHT WILL ARE NOT FAR FROM A MAV/MET BLEND...IN THE UPPER
20S TO LOWER 30S ACROSS THE AREA.
TUESDAY INTO WEDNESDAY...HIGH PRESSURE WILL BEGIN TO BUILD IN FROM
THE SOUTHWEST ON TUESDAY. A COLD WEST-NORTHWESTERLY 850MB FLOW WILL
ALLOW FOR THE CHANCE OF SNOW SHOWERS TO LINGER INTO THE EARLY
AFTERNOON FOR LOCATIONS NORTH AND EAST OF PITTSBURGH. 850MB FLOW
THEN BACKS TO MORE SOUTHWESTERLY AND WILL ALLOW FOR DECREASING CLOUD
COVERAGE TUESDAY NIGHT. AS THE HIGH MOVES OVER THE AREA ON
WEDNESDAY...MORE ABUNDANT SUNSHINE IS ANTICIPATED. WITH THE CORE OF
THE COOLEST AIR ACROSS THE AREA ON TUESDAY...HIGHS WILL BE AROUND A
FEW DEGREES BELOW NORMAL...STRUGGLING TO REACH 40. CLEARING SKIES
TUESDAY NIGHT WILL ALLOW FOR SOME RADIATIONAL COOLING...WITH LOWS IN
THE LOW TO MID 20S ACROSS THE AREA. MORE SUNSHINE WEDNESDAY WILL
CONTRIBUTE TO HIGHS NEAR SEASONAL VALUES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MODELS AGREE ON A QUIET START TO THE LONG RANGE WITH A SURFACE RIDGE
AXIS EXTENDING FROM NEW ENGLAND TO THE LOWER MISSISSIPPI VALLEY
DOMINATING THROUGH FRIDAY NIGHT. THIS WILL BRING DRY AND A BIT ABOVE
AVERAGE TEMPERATURES.
BY LATER SATURDAY A DEVELOPING STORM SYSTEM ACROSS THE CENTRAL
PLAINS WILL BEGIN TO SPREAD MOISTURE ACROSS THE OHIO VALLEY WITH
SHOWERS INCREASING AND CONTINUING SUNDAY AS LOW PRESSURE HEADS TO
THE WESTERN GREAT LAKES. ALL RAIN EXPECTED WITH THIS SYSTEM WITH
TEMPERATURES WELL ABOVE NORMAL.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
GENERAL MVFR ACROSS REGION WITH OCCASIONAL VFR PATCHES MOVING ACROSS
TERMINALS. AREA OF RAIN NOW INTO EASTERN OHIO WILL SPREAD ACROSS
REMAINDER OF TERMINALS THIS AFTERNOON. CIGS WILL LOWER TO IFR AFTER
A FEW HOURS OF RAIN BY THIS EVENING.
WINDS WILL BE GENERALLY FROM THE EAST NEAR 10 KTS. UNTIL FRONT
PUSHES NORTH LATER TONIGHT WHEN SOUTH WINDS AT SIMILAR SPEEDS
EXPECTED.
.OUTLOOK.../MONDAY THROUGH FRIDAY/...
IFR RESTRICTIONS WL CONTINUE WITH RAIN MONDAY AS A COLD FRONT MOVES
THROUGH. MVFR CONDITIONS ARE EXPECTED MONDAY NIGHT INTO TUESDAY.
LINGERING RAIN SHOWERS MAY CHANGE TO SCATTERED SNOW SHOWERS BEFORE
ENDING EARLY TUESDAY. HIGH PRES AND VFR CONDS ARE EXPECTED LATER
TUESDAY NIGHT THROUGH FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
301 PM EST SUN DEC 9 2012
.SYNOPSIS...
A SURFACE LOW WILL PUSH NORTHEAST INTO THE OHIO VALLEY THIS
EVENING AND LIFT A WARM FRONT INTO THE REGION. THIS WILL ALLOW
FOR SHOWERS TO MOVE ACROSS THE AREA AND CONTINUE INTO MONDAY. A COLD
FRONT WILL CROSS THE AREA ON MONDAY...ALLOWING FOR A CHANGE OVER
TO SNOW SHOWERS MONDAY NIGHT WITH A MUCH COOLER AIR MASS BUILDING
INTO THE AREA FOR THE MID-WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A TROUGH MOVING FROM
THE NORTHERN PLAINS INTO THE UPPER MIDWEST WITH THE UPPER OHIO
VALLEY IN A SOUTHWESTERLY FLOW WELL AHEAD OF THIS FEATURE. AT THE
SURFACE...THERE ARE TWO LOWS WELL UPSTREAM...ONE MOVING ACROSS THE
UPPER MIDWEST AND ANOTHER ACROSS THE MISSOURI VALLEY. THE FRONTAL
BOUNDARY BETWEEN THESE TWO LOWS IS THE DEMARCATION BETWEEN A WARM
AND MOIST AIR MASS AHEAD OF IT AND ARCTIC AIR BUILDING IN BEHIND IT.
A WARM FRONT EXTENDS NORTHEASTWARD FROM THE SOUTHERN LOW ACROSS
SOUTHERN OHIO AND INTO CENTRAL WV. LOCALLY...THE NEXT WAVE IS
RIDING ALONG AND NORTH OF THE WARM FRONT AND DEVELOPING AS IT
PUSHES INTO EASTERN OHIO AND NORTH-CENTRAL WV.
THIS EVENING...THE SURFACE LOW ACROSS THE MISSOURI VALLEY WILL
QUICKLY LIFT INTO THE OHIO VALLEY...MERGING WITH THE LOW IN THE UPPER
MIDWEST AND PULLING THE WARM FRONT NORTHWARD INTO THE UPPER OHIO
VALLEY. THE AREA OF SHOWERS ASSOCIATED WITH THE SHORT WAVE IS CURRENTLY
MOVING INTO THE AREA WILL SLIDE NORTHEASTWARD WITH THE WARM FRONT
AND PUSH INTO WESTERN PA. MESOSCALE MODELS ARE SUPPORTIVE OF THIS
FEATURE MOVING THROUGH MOST OF THE AREA BY LATE EVENING...AND THUS
POPS INCREASE TO CATEGORICAL.
TEMPS WILL BE SUBJECT TO THE NORTHWARD PROGRESSION OF THE WARM
FRONT. LAMP/WRF-NMM SUGGEST TEMPS WILL BE SLOW TO WARM WITH A WARM
SURGE OCCURRING AND HIGH TEMPS OCCURRING AFTER 21Z.
TONIGHT...THE MERGED SURFACE LOW WILL CROSS THE OHIO VALLEY AND PUSH
INTO THE EASTERN GREAT LAKES. ITS WARM FRONT WILL SHIFT NORTHEAST
OF THE AREA AND A COLD FRONT AND ITS ASSOCIATED SURFACE TROUGH
WILL BEGIN TO APPROACH FROM THE WEST. BETWEEN WARM FRONTAL SHOWERS
AND SHOWERS AHEAD OF THE COLD FRONT MOVING IN FROM THE
WEST...CATEGORICAL POPS ARE FORECAST THROUGH MUCH OF THE
OVERNIGHT. TEMPS WILL REMAIN INCREASE A FEW DEGREES OVERNIGHT IN
WAA...WITH LOWS RANGING FROM THE MID 50S IN NORTH- CENTRAL WV TO
THE LOWER 30S NORTH OF THE I-80 CORRIDOR.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
GFS/NAM/ECMWF ARE IN AGREEMENT THAT THE MID-LEVEL TROUGH WILL
DE-AMPLIFY AS IS SLIDES EASTWARD ACROSS THE GREAT LAKES AND PUSHES A
COLD FRONT ACROSS THE UPPER OHIO VALLEY ON MONDAY. A MODEL CONSENSUS
OF THE EQUIVALENT POTENTIAL TEMPERATURE GRADIENT INDICATES A COLD
FRONT JUST NORTHWEST OF THE PITTSBURGH METRO AROUND 18Z ON MONDAY.
AHEAD OF THE FRONT...H5 VORTICITY INDICATES ENERGY IN WAA THAT WILL
ALLOW FOR SCATTERED SHOWERS AHEAD OF THE FRONT. A WELL-DEFINED
SURFACE TROUGH ASSOCIATED WITH THE COLD FRONT ALONG WITH THE STRONG
THERMAL GRADIENT ALONG THE FRONT WILL ALSO PROVIDE SUFFICIENT
FORCING FOR SHOWERS ALONG AND BEHIND THE FRONT. WITH THIS IN
MIND...CATEGORICAL POPS ARE FORECAST ACROSS THE MAJORITY OF THE AREA
THROUGH 21Z. WITH THE STRENGTH OF THE FRONT...VERY WEAK
INSTABILITY...AND STRONG SHEAR IN PLACE...HAVE INCLUDED A SCHC
THUNDER MENTION LATE MONDAY MORNING INTO THE EARLY AFTERNOON.
AHEAD OF THE FRONT...ONGOING WAA WILL ALLOW TEMPS TO BE IN THE UPPER
50S ACROSS MANY LOCATIONS WITH EVEN TEMPS NEAR 60 POSSIBLE IN
NORTH-CENTRAL WV.
CAA WILL ENSUE ACROSS THE ENTIRE AREA BY 00Z TUESDAY AS THE FRONT
SHIFTS SOUTHEAST OF THE AREA. WITH STRONG CAA...850MB TEMPS WILL
COOL TO AROUND 6-8C BY 12Z TUESDAY. 1000-500MB THICKNESS LINE DROPS
SOUTHEASTWARD QUICKLY OVERNIGHT AND IN RETURN...ANY LINGERING RAIN
SHOWERS WILL TURN TO SNOW SHOWERS BEHIND THE FRONT. SNOW
ACCUMULATION WILL BE LIGHT...WITH A DUSTING IN MOST LOWLAND
LOCATIONS AND UP TO AN INCH POSSIBLE ACROSS THE EASTERN RIDGES. LOWS
ON MONDAY NIGHT WILL ARE NOT FAR FROM A MAV/MET BLEND...IN THE UPPER
20S TO LOWER 30S ACROSS THE AREA.
TUESDAY INTO WEDNESDAY...HIGH PRESSURE WILL BEGIN TO BUILD IN FROM
THE SOUTHWEST ON TUESDAY. A COLD WEST-NORTHWESTERLY 850MB FLOW WILL
ALLOW FOR THE CHANCE OF SNOW SHOWERS TO LINGER INTO THE EARLY
AFTERNOON FOR LOCATIONS NORTH AND EAST OF PITTSBURGH. 850MB FLOW
THEN BACKS TO MORE SOUTHWESTERLY AND WILL ALLOW FOR DECREASING CLOUD
COVERAGE TUESDAY NIGHT. AS THE HIGH MOVES OVER THE AREA ON
WEDNESDAY...MORE ABUNDANT SUNSHINE IS ANTICIPATED. WITH THE CORE OF
THE COOLEST AIR ACROSS THE AREA ON TUESDAY...HIGHS WILL BE AROUND A
FEW DEGREES BELOW NORMAL...STRUGGLING TO REACH 40. CLEARING SKIES
TUESDAY NIGHT WILL ALLOW FOR SOME RADIATIONAL COOLING...WITH LOWS IN
THE LOW TO MID 20S ACROSS THE AREA. MORE SUNSHINE WEDNESDAY WILL
CONTRIBUTE TO HIGHS NEAR SEASONAL VALUES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MODELS AGREE ON A QUIET START TO THE LONG RANGE WITH A SURFACE RIDGE
AXIS EXTENDING FROM NEW ENGLAND TO THE LOWER MISSISSIPPI VALLEY
DOMINATING THROUGH FRIDAY NIGHT. THIS WILL BRING DRY AND A BIT ABOVE
AVERAGE TEMPERATURES.
BY LATER SATURDAY A DEVELOPING STORM SYSTEM ACROSS THE CENTRAL
PLAINS WILL BEGIN TO SPREAD MOISTURE ACROSS THE OHIO VALLEY WITH
SHOWERS INCREASING AND CONTINUING SUNDAY AS LOW PRESSURE HEADS TO
THE WESTERN GREAT LAKES. ALL RAIN EXPECTED WITH THIS SYSTEM WITH
TEMPERATURES WELL ABOVE NORMAL.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
GENERAL MVFR ACROSS REGION WITH OCCASIONAL VFR PATCHES MOVING ACROSS
TERMINALS. AREA OF RAIN NOW INTO EASTERN OHIO WILL SPREAD ACROSS
REMAINDER OF TERMINALS THIS AFTERNOON. CIGS WILL LOWER TO IFR AFTER
A FEW HOURS OF RAIN BY THIS EVENING.
WINDS WILL BE GENERALLY FROM THE EAST NEAR 10 KTS. UNTIL FRONT
PUSHES NORTH LATER TONIGHT WHEN SOUTH WINDS AT SIMILAR SPEEDS
EXPECTED.
.OUTLOOK.../MONDAY THROUGH FRIDAY/...
IFR RESTRICTIONS WL CONTINUE WITH RAIN MONDAY AS A COLD FRONT MOVES
THROUGH. MVFR CONDITIONS ARE EXPECTED MONDAY NIGHT INTO TUESDAY.
LINGERING RAIN SHOWERS MAY CHANGE TO SCATTERED SNOW SHOWERS BEFORE
ENDING EARLY TUESDAY. HIGH PRES AND VFR CONDS ARE EXPECTED LATER
TUESDAY NIGHT THROUGH FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
116 PM EST SUN DEC 9 2012
.SYNOPSIS...
A SURFACE LOW WILL PUSH NORTHEAST INTO THE OHIO VALLEY THIS
AFTERNOON AND LIFT A WARM FRONT INTO THE REGION. THIS WILL ALLOW
FOR SHOWERS TO RETURN TO THE AREA AND CONTINUE INTO MONDAY. A COLD
FRONT WILL CROSS THE AREA ON MONDAY...ALLOWING FOR A CHANGE OVER
TO SNOW SHOWERS MONDAY NIGHT WITH A MUCH COOLER AIR MASS BUILDING
INTO THE AREA FOR THE MID-WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST HAS BEEN ISSUED TO ACCOUNT FOR
THE LATEST POSITION OF THE NEXT WAVE OF SHOWERS MOVING INTO THE
AREA.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A TROUGH MOVING FROM
THE NORTHERN PLAINS INTO THE UPPER MIDWEST WITH THE UPPER OHIO
VALLEY IN A SOUTHWESTERLY FLOW WELL AHEAD OF THIS FEATURE. AT THE
SURFACE...THERE ARE TWO LOWS WELL UPSTREAM...ONE MOVING ACROSS THE
UPPER MIDWEST AND ANOTHER ACROSS THE MISSOURI VALLEY. THE FRONTAL
BOUNDARY BETWEEN THESE TWO LOWS IS THE DEMARCATION BETWEEN A WARM
AND MOIST AIR MASS AHEAD OF IT AND ARCTIC AIR BUILDING IN BEHIND IT.
A WARM FRONT EXTENDS NORTHEASTWARD FROM THE SOUTHERN LOW ACROSS
SOUTHERN OHIO AND INTO CENTRAL WV. LOCALLY...THE NEXT WAVE IS
RIDING ALONG AND NORTH OF THE WARM FRONT AND DEVELOPING AS IT
PUSHES INTO EASTERN OHIO AND NORTH-CENTRAL WV.
THIS AFTERNOON...THE SURFACE LOW ACROSS THE MISSOURI VALLEY WILL
QUICKLY LIFT INTO THE OHIO VALLEY...MERGING WITH THE LOW IN THE UPPER
MIDWEST AND PULLING THE WARM FRONT NORTHWARD INTO THE UPPER OHIO
VALLEY. THE AREA OF SHOWERS ASSOCIATED WITH THE SHORT WAVE IN
CURRENTLY MOVING INTO THE AREA WILL SLIDE NORTHEASTWARD WITH THE WARM
FRONT AND PUSH INTO WESTERN PA. MESOSCALE MODELS ARE SUPPORTIVE OF
THIS FEATURE MOVING THROUGH MOST OF THE AREA BY LATE EVENING...AND
THUS POPS INCREASE TO CATEGORICAL BY 00Z.
RAP/NAM MODEL SOUNDINGS AT KZZV INDICATE SOME NARROW CAPE
DEVELOPING (LESS THAN 200 J/KG) AFTER 21Z. WITH THE WARM FRONT
LIFTING INTO THE AREA AND TDS SURGING INTO THE LOWER TO MID
50S...HAVE ADDED THE SCHC OF THUNDER THIS AFTERNOON INTO THE
EVENING FOR LOCATIONS SOUTH AND WEST OF PITTSBURGH.
TEMPS TODAY WILL SUBJECT TO THE NORTHWARD PROGRESSION OF THE WARM
FRONT. LAMP/WRF-NMM SUGGEST TEMPS WILL BE SLOW TO WARM MUCH OF THE
DAY WITH THE WARM SURGE OCCURRING AND HIGH TEMPS OCCURRING AFTER
21Z. THUS...WITH THE FRONT PUSHING INTO THE AREA...QUITE A THERMAL
GRADIENT CAN BE EXPECTED FOR HIGHS TODAY THAT WILL RANGE FROM THE
LOWER 40S IN JEFFERSON/FOREST COUNTIES TO THE LOWER 60S IN
PORTIONS OF NORTH-CENTRAL WV AND EASTERN OHIO.
TONIGHT...THE MERGED SURFACE LOW WILL CROSS THE OHIO VALLEY AND PUSH
INTO THE EASTERN GREAT LAKES. THE WARM FRONT WILL SHIFT NORTHEAST
OF THE AREA AND A COLD FRONT AND ITS ASSOCIATED SURFACE TROUGH WILL
BEGIN TO APPROACH FROM THE WEST. BETWEEN WARM FRONTAL SHOWERS AND
SCHC THUNDER INITIALLY AND SHOWERS AHEAD OF THE COLD FRONT MOVING
IN FROM THE WEST...CATEGORICAL POPS ARE FORECAST THROUGH MUCH OF
THE OVERNIGHT. TEMPS WILL DROP OFF LITTLE OVERNIGHT IN WAA...WITH
LOWS RANGING FROM THE MID 50S IN NORTH-CENTRAL WV TO THE MID 40S
ALONG THE I-80 CORRIDOR.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
THE SURFACE TROUGH AND COLD FRONT WILL CROSS THE AREA THROUGH THE
EARLY PART OF THE DAY...WITH CATEGORICAL POPS. TEMPERATURES WILL
REMAIN MILD WITH VALUES MAINLY IN THE UPPER 40S TO MID 50S INTO
MIDDAY MONDAY. STRONG CAA WILL THEN BEGIN BEHIND THE FRONT...AS
THE AFOREMENTIONED ARCTIC AIR MASS BEGINS TO PUSH IN FROM THE
WEST. BEFORE RAIN COMES TO AN END OR CHANGES TO SNOW...CONCUR WITH
HPC THAT RAINFALL AMOUNTS FOR SUNDAY INTO MONDAY WILL BE ON THE
ORDER OF 1.0 TO 1.3 INCHES.
CONSEQUENTLY REMAINING POSTFRONTAL SHOWERS MONDAY NIGHT WILL TURN
TO SNOW SHOWERS LATE. THE POSTFRONTAL COLD POOL WILL REMAIN
ACROSS THE UPPER OHIO VALLEY INTO WEDNESDAY...KEEPING SKIES MAINLY
CLOUDY. HOWEVER CONDITIONS TUESDAY INTO WEDNESDAY SHOULD BE DRY AS
INCOMING HIGH PRESSURE SUBSIDENCE AND LOW LEVEL WESTERLY WINDS
WILL MITIGATE CHANCES OF LAKE EFFECT SNOW SHOWER DEVELOPMENT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS ECMWF AND CANADIAN MODEL OUTPUT CONCUR THAT NEARBY HIGH
PRESSURE WILL PROMOTE DRY CONDITIONS WEDNESDAY NIGHT INTO FRIDAY.
ECMWF AND GFS AGREE THAT A CLOSED MID-LEVEL LOW WILL DEVELOP
ACROSS THE CENTRAL PLAINS ON FRIDAY NIGHT AND SHIFT INTO THE GREAT
LAKES REGION BY SATURDAY. AHEAD OF THIS FEATURE...CHANCE POPS
RETURN TO THE AREA. MODEL PREDICTABILITY A WEEK OUT MAKES IT
DIFFICULT TO PIN DOWN SPECIFICS IN FRONTAL PLACEMENT...HOWEVER
THIS PATTERN FAVORS THE POTENTIAL FOR OVERRUNNING ALONG WITH WARM
FRONTAL RAIN SHOWERS WELL AHEAD OF THE LOW.
TEMPERATURES WILL REBOUND TO WARMER THAN NORMAL THIS PERIOD WITH
VALUES FRIDAY AND SATURDAY ANYWHERE FROM 5 TO 10 DEGREES ABOVE
NORMAL.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
GENERAL MVFR ACROSS REGION WITH OCCASIONAL VFR PATCHES MOVING ACROSS
TERMINALS. AREA OF RAIN NOW MOVING INTO EASTERN OHIO AND WILL BE
INTO KZZV AFTER 18Z AND SPREAD ACROSS REMAINDER OF TERMINALS THIS
AFTERNOON. CIGS WILL LOWER TO IFR AFTER A FEW HOURS OF RAIN BY THIS
EVENING.
WINDS WILL BE GENERALLY FROM THE EAST NEAR 10 KTS. UNTIL FRONT
PUSHES NORTH LATER TONIGHT WHEN SOUTH WINDS AT SIMILAR SPEEDS
EXPECTED.
.OUTLOOK.../MONDAY THROUGH THURSDAY/...
IFR RESTRICTIONS WL CONTINUE WITH RAIN MONDAY AS A COLD FRONT MOVES
THROUGH. MVFR CONDITIONS ARE EXPECTED MONDAY NIGHT INTO TUESDAY.
LINGERING RAIN SHOWERS MAY CHANGE TO SCATTERED SNOW SHOWERS BEFORE
ENDING EARLY TUESDAY. HIGH PRES AND VFR CONDS ARE EXPECTED LATER
TUESDAY THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1237 PM CST SUN DEC 9 2012
.UPDATE...UPDATED FOR AVIATION DISCUSSION BELOW.
&&
.PREV DISCUSSION.../ISSUED 1012 AM CST SUN DEC 9 2012/
.UPDATE...
INCREASED THE SNOW AMOUNTS FOR TODAY INTO THIS EVENING DUE TO A
SLOWER TREND OF THIS SYSTEM EXITING...IMPRESSIVE FORCING...HIGH
QPF NUMBERS...AND WHAT HAS ALREADY BEEN REPORTED. MANY REPORTS OF
6 TO 10 INCHES HAVE BEEN RECEIVED ACROSS CENTRAL AND WESTERN
MINNESOTA WITH AT LEAST ANOTHER 3 TO 6 INCHES EXPECTED TODAY AND
THIS EVENING. FURTHER EAST TOWARD THE TWIN CITIES METRO AND FAR
WRN WI...3 TO 4 INCHES WERE REPORTED THIS MORNING WITH ANOTHER 7 TO
10 EXPECTED TODAY AND THIS EVENING. THUS...HAVE A LARGE SWATH OF 9
TO 15 INCHES ACROSS MOST OF THE CWA...EXCEPT FOR FAR SOUTHERN
MINNESOTA WHERE RADAR AND SATELLITE INDICATES A DRY SLOT BEGINNING
TO MOVE IN. LOCALLY HIGHER AMOUNTS ARE CERTAINLY POSSIBLE. THE
LOW WILL CONTINUE TRACKING DUE EAST ACROSS FAR SRN MN TODAY...SO
WILL LEAVE THE HEADLINES AS THEY ARE WITH WARNINGS NORTH OF THE
LOW TRACK AND AN ADVISORY ALONG AND SOUTH.
A ROBUST INCREASE IN SNOW INTENSITY HAS OCCURRED IN THE PAST 30 TO
60 MINUTES FROM THE TC METRO SOUTHWEST TO REDWOOD FALLS. EXPECT
RATES WITHIN THIS AREA TO REACH 1 TO 2 INCHES PER HOUR THROUGH THE
REST OF THE MORNING INTO THE EARLY AFTERNOON WITH ADDITIONAL HEAVY
SNOW JUST NORTH OF THE LOW TRACK LATE THIS AFTERNOON AND EARLY
THIS EVENING.
STRONG COLD FRONT ALONG THE MN BORDER WILL BEGIN PUSHING EAST THIS
AFTERNOON. TEMPERATURES WEST OF THE BOUNDARY ARE IN THE SINGLE
DIGITS WITH NORTH WINDS GUSTING HIGHER THAN 30 KTS. WHITEOUT
CONDITIONS HAVE BEEN REPORTED OVER EASTERN SD. AS THE LOW PULLS
EAST...EXPECT AREAS ACROSS SWRN MN TO FOLLOW SUIT. WITH REPORTS OF
6 TO 10 INCHES OVER FAR WRN MN AND SEVERAL MORE POSSIBLE...DRIFTS
WILL BE RATHER SIGNIFICANT AND TRAVEL WILL BECOME IMPOSSIBLE.
UPDATED THE GRIDS FOR THESE CURRENT TRENDS...INCLUDING EXTENDING
THE HEAVY SNOW INTO THE EVENING ACROSS THE EAST.
BORGHOFF
&&
.PREV DISCUSSION... /ISSUED 539 AM CST SUN DEC 9 2012/
OVERVIEW...UPDATED FORECAST TO ACCOUNT FOR SOUTHERLY SHIFT OF
WINTER STORM AFFECTING THE AREA TODAY. THIS PUTS THE TWIN CITIES
METRO AREA RIGHT IN THE SWATH OF HEAVIEST SNOWFALL. MINOR
ADJUSTMENTS TO THE WINTER WEATHER HEADLINES OVERNIGHT. ADDED
MCLEOD AND MEEKER COUNTIES TO THE BLIZZARD WARNING AND LE
SUEUR...RICE AND GOODHUE TO THE WINTER STORM WARNING. FRESH SNOW
COVER MIGHT KEEP US A BIT COOLER THAN FORECAST TEMPERATURES THIS
WEEK. NO MAJOR CHANGES TO FORECAST BEYOND THIS WEEKEND.
BEEN WATCHING PERSISTENT LIGHT TO MODERATE SNOWFALL ACROSS
MINNESOTA FOR THE LAST 4 TO 5 HOURS NOW. AIRPORTS REPORTING MAINLY
REPORTING 3/4SM TO 1 1/2SM VISIBILITY AND A LOT OF AREA HAVE
PICKED UP AND INCH OR TWO OF SNOW. FINALLY...STARTING TO GET
SITES MEASURE IN WISCONSIN...BUT REALLY AREN`T SEEING MUCH HEAVY
SNOW OUT THERE EARLY THIS MORNING AFTER THE INITIAL BAND NEAR THE
MN/SD BORDER BROKE UP AROUND MIDNIGHT. SNOW RATES IN YELLOW
MEDICINE AND LAC QUI PARLE WERE NEAR AN INCH PER HOUR LAST
EVENING...WITH SITES NEAR THE STATE LINE QUICKLY PICKING UP 4-5"
IN A FEW HOURS TIME. THE 00Z MPX SOUNDING...ALONG
FSD AND ABR VAD PROFILES SHOW A STRONG WAA REGIME...WHICH SHOULD
BE ENHANCED BY THE APPROACHING UPPER TROUGH AND INCREASING MID-
LEVEL FRONTAL-GENESIS. CONSEQUENTLY...THIS BAND IS EXPECTED TO
PERSIST INTO SWRN MN...FAR NERN SD...AND FAR SERN ND. SNOWFALL
RATES ARE GENERALLY EXPECTED TO REMAIN BELOW 1 INCH/HOUR BUT
BRIEF/ISOLATED RATES GREATER THAN 1 INCH/HOUR ARE POSSIBLE.
THERE WAS GOOD MODEL CONSENSUS AMONG THE 09.00Z RUNS OF A SLIGHT
SOUTHWARD SHIFT TO THE SURFACE LOW TRACK. THE RAP13 AND 00Z NAM
WERE THE FIRST TO SUGGEST THIS AND THE 00Z GFS CAME ALMOST
PERFECTLY IN LINE WITH THE NAM. WHAT IS A CONCERN IS THE ALMOST
IDENTICAL PLACEMENT OF 14-16" SNOWFALL IN THE WEST TWIN CITIES
METRO AND COUNTIES JUST WEST OF HERE. 09.00Z LOCAL WRF-ARW AND
09.08Z RAP ALSO HAVE HIGH END SNOWFALL RIGHT IN THE CENTER OF OUR CWA
GIVEN THE SLOW MOVEMENT AND TRACK OF THE SURFACE/850MB/700MB LOW
CENTERS. THE RAP HAS 20 INCHES...LIKELY OVERDONE BUT IT`S HINTING
AT THE POTENTIAL FOR SOMETHING SIGNIFICANT. THE PV FEATURE
ASSOCIATED WITH THIS SYSTEM IS IMPRESSIVE AND ITS ORIENTATION
SUGGESTS A LONGER THAN EXPECTED PERIOD OF SNOW TODAY. ALREADY
SEEING EVIDENCE OF A CIRCULATION IN THE REFLECTIVITY ACROSS SW
MN. THIS SHOULD FEATURE SHOULD LIFT NORTH...BECOME ANCHORED
PRODUCE 0.75-1.5" SNOWFALL RATES LATE THIS MORNING AND EARLY THIS
AFTERNOON. INCREASED THE SNOWFALL IN THE TWIN CITIES METRO TO 8-11
INCHES...AND HOPEFULLY THAT IS ENOUGH TO COVER IT. DEPTH OF SNOW
GROWTH REGION ISN`T OVERLY IMPRESSIVE...BUT WE SHOULD STILL MANAGE
SNOW RATIOS NEAR CLIMATOLOGY 13-14:1 OR SO. FURTHERMORE...ON THE
NOSE OF THE PV FEATURE...JUST AHEAD OF DRY SLOT...STATIC STABILITY
BECOMES WEAK AND SUGGESTS BANDED PRECIP COULD BE FACTORING IN TO
HELP SNOW TOTALS. OTHERWISE...WARMED TEMPS TONIGHT WITH THE SLOWER
PROGRESSION AND KEPT THE WIND ABOUT THE SAME...PERHAPS A BIT LESS.
THEREFORE WIND CHILLS AREN`T AS COLD WITH THIS MORNING`S FORECAST.
IN THE EXTENDED...HEIGHTS BEGIN TO BUILD BACK ON WEDNESDAY...SO
SHOULD ALREADY SEE MODERATING TEMPS FROM A COLD MONDAY AND
TUESDAY. A COUPLE WEAK CLIPPER SYSTEM LOOK TO PASS NORTH OF THE
AREA THIS WEEK...BUT THERE IS ANOTHER POTENTIALLY SIGNIFICANT
STORM ON THE HORIZON 6-7 DAYS FROM NOW.
&&
.AVIATION.../18Z TAF ISSUANCE/
WIDESPREAD MODERATE TO HEAVY SNOW CONTINUES THIS AFTERNOON FOR
MOST OF THE TERMINALS. DRY SLOT AS SEEN ON RADAR IS APPROACHING
RWF...BUT WILL PROBABLY STALL JUST SOUTH. NONE OF THE OTHER
TERMINALS ARE EXPECTED TO BE IMPACTED BY A DRY SLOT AND WILL
CONTINUE SNOWING FOR THE NEXT 6 TO 9 HOURS. BLIZZARD CONDITIONS
ARE HEADED EAST ACROSS THE MN/SD BORDER AND COULD IMPACT RWF AND
AXN LATER THIS AFTERNOON AND EARLY EVENING WITH SOME GUSTS TO 30
OR 35 KTS. PUSHED BACK THE CLEARING AND IMPROVING VISIBILITIES A
COUPLE HOURS OVER ERN MN AND WRN WI WITH LINGERING SNOW. VFR
CONDITIONS WILL REACH AXN AND RWF LATER TONIGHT...STC BY MONDAY
MORNING...AND NOT UNTIL MONDAY AFTERNOON AT MSP/RNH/EAU.
KMSP...
A SOLID AREA OF +SN CONTINUES TO ENGULF THE TERMINAL...WHICH IS
EXPECTED TO CONTINUE FOR THE MAJORITY OF THE AFTERNOON JUST NORTH
OF THE LOW TRACK. DRY SLOT AS EVIDENT ON RADAR IS APPROACHING...
BUT THINK IT WILL FILL IN NORTH OF THE LOW KEEPING SNOW GOING ALL
AFTERNOON. SNOW WILL TAPER OFF THIS EVENING WITH OCCASIONAL LIGHT
SNOW OR FLURRIES CONTINUING OVERNIGHT. SOME BLOWING SNOW IS
POSSIBLE...BUT BEST CHANCES REMAIN WELL WEST. CLEARING SKIES AND
IMPROVING CIGS WILL ARRIVE BY LATE MORNING MONDAY WITH VFR
EXPECTED THEREAFTER. WINDS WILL BACK FROM EAST TO NORTH THIS
AFTERNOON AND THEN BECOME WEST BY MONDAY AFTERNOON.
/OUTLOOK FOR KMSP/
MON...MVFR/IFR CIGS POSSIBLE EARLY. THEN VFR. WINDS WNW AT 10G15KTS.
TUE...MVFR/IFR CIGS POSSIBLE. FLURRIES. WINDS SW AT 10G15KTS.
WED...MVFR/IFR CIGS POSSIBLE EARLY. WINDS S AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR ANOKA-BENTON-
CARVER-CHISAGO-DAKOTA-GOODHUE-HENNEPIN-ISANTI-KANABEC-LE
SUEUR-MILLE LACS-MORRISON-RAMSEY-RICE-SCOTT-SHERBURNE-
STEARNS-TODD-WASHINGTON-WRIGHT.
BLIZZARD WARNING UNTIL MIDNIGHT CST TONIGHT FOR BROWN-CHIPPEWA-
DOUGLAS-KANDIYOHI-LAC QUI PARLE-MCLEOD-MEEKER-NICOLLET-POPE-
REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BLUE
EARTH-FARIBAULT-FREEBORN-MARTIN-STEELE-WASECA-WATONWAN.
WI...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BARRON-
CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
CLF/BORGHOFF
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1012 AM CST SUN DEC 9 2012
.UPDATE...
INCREASED THE SNOW AMOUNTS FOR TODAY INTO THIS EVENING DUE TO A
SLOWER TREND OF THIS SYSTEM EXITING...IMPRESSIVE FORCING...HIGH
QPF NUMBERS...AND WHAT HAS ALREADY BEEN REPORTED. MANY REPORTS OF
6 TO 10 INCHES HAVE BEEN RECEIVED ACROSS CENTRAL AND WESTERN
MINNESOTA WITH AT LEAST ANOTHER 3 TO 6 INCHES EXPECTED TODAY AND
THIS EVENING. FURTHER EAST TOWARD THE TWIN CITIES METRO AND FAR
WRN WI...3 TO 4 INCHES WERE REPORTED THIS MORNING WITH ANOTHER 7 TO
10 EXPECTED TODAY AND THIS EVENING. THUS...HAVE A LARGE SWATH OF 9
TO 15 INCHES ACROSS MOST OF THE CWA...EXCEPT FOR FAR SOUTHERN
MINNESOTA WHERE RADAR AND SATELLITE INDICATES A DRY SLOT BEGINNING
TO MOVE IN. LOCALLY HIGHER AMOUNTS ARE CERTAINLY POSSIBLE. THE
LOW WILL CONTINUE TRACKING DUE EAST ACROSS FAR SRN MN TODAY...SO
WILL LEAVE THE HEADLINES AS THEY ARE WITH WARNINGS NORTH OF THE
LOW TRACK AND AN ADVISORY ALONG AND SOUTH.
A ROBUST INCREASE IN SNOW INTENSITY HAS OCCURRED IN THE PAST 30 TO
60 MINUTES FROM THE TC METRO SOUTHWEST TO REDWOOD FALLS. EXPECT
RATES WITHIN THIS AREA TO REACH 1 TO 2 INCHES PER HOUR THROUGH THE
REST OF THE MORNING INTO THE EARLY AFTERNOON WITH ADDITIONAL HEAVY
SNOW JUST NORTH OF THE LOW TRACK LATE THIS AFTERNOON AND EARLY
THIS EVENING.
STRONG COLD FRONT ALONG THE MN BORDER WILL BEGIN PUSHING EAST THIS
AFTERNOON. TEMPERATURES WEST OF THE BOUNDARY ARE IN THE SINGLE
DIGITS WITH NORTH WINDS GUSTING HIGHER THAN 30 KTS. WHITEOUT
CONDITIONS HAVE BEEN REPORTED OVER EASTERN SD. AS THE LOW PULLS
EAST...EXPECT AREAS ACROSS SWRN MN TO FOLLOW SUIT. WITH REPORTS OF
6 TO 10 INCHES OVER FAR WRN MN AND SEVERAL MORE POSSIBLE...DRIFTS
WILL BE RATHER SIGNIFICANT AND TRAVEL WILL BECOME IMPOSSIBLE.
UPDATED THE GRIDS FOR THESE CURRENT TRENDS...INCLUDING EXTENDING
THE HEAVY SNOW INTO THE EVENING ACROSS THE EAST.
BORGHOFF
&&
.PREV DISCUSSION...
/ISSUED 539 AM CST SUN DEC 9 2012/
OVERVIEW...UPDATED FORECAST TO ACCOUNT FOR SOUTHERLY SHIFT OF
WINTER STORM AFFECTING THE AREA TODAY. THIS PUTS THE TWIN CITIES
METRO AREA RIGHT IN THE SWATH OF HEAVIEST SNOWFALL. MINOR
ADJUSTMENTS TO THE WINTER WEATHER HEADLINES OVERNIGHT. ADDED
MCLEOD AND MEEKER COUNTIES TO THE BLIZZARD WARNING AND LE
SUEUR...RICE AND GOODHUE TO THE WINTER STORM WARNING. FRESH SNOW
COVER MIGHT KEEP US A BIT COOLER THAN FORECAST TEMPERATURES THIS
WEEK. NO MAJOR CHANGES TO FORECAST BEYOND THIS WEEKEND.
BEEN WATCHING PERSISTENT LIGHT TO MODERATE SNOWFALL ACROSS
MINNESOTA FOR THE LAST 4 TO 5 HOURS NOW. AIRPORTS REPORTING MAINLY
REPORTING 3/4SM TO 1 1/2SM VISIBILITY AND A LOT OF AREA HAVE
PICKED UP AND INCH OR TWO OF SNOW. FINALLY...STARTING TO GET
SITES MEASURE IN WISCONSIN...BUT REALLY AREN`T SEEING MUCH HEAVY
SNOW OUT THERE EARLY THIS MORNING AFTER THE INITIAL BAND NEAR THE
MN/SD BORDER BROKE UP AROUND MIDNIGHT. SNOW RATES IN YELLOW
MEDICINE AND LAC QUI PARLE WERE NEAR AN INCH PER HOUR LAST
EVENING...WITH SITES NEAR THE STATE LINE QUICKLY PICKING UP 4-5"
IN A FEW HOURS TIME. THE 00Z MPX SOUNDING...ALONG
FSD AND ABR VAD PROFILES SHOW A STRONG WAA REGIME...WHICH SHOULD
BE ENHANCED BY THE APPROACHING UPPER TROUGH AND INCREASING MID-
LEVEL FRONTAL-GENESIS. CONSEQUENTLY...THIS BAND IS EXPECTED TO
PERSIST INTO SWRN MN...FAR NERN SD...AND FAR SERN ND. SNOWFALL
RATES ARE GENERALLY EXPECTED TO REMAIN BELOW 1 INCH/HOUR BUT
BRIEF/ISOLATED RATES GREATER THAN 1 INCH/HOUR ARE POSSIBLE.
THERE WAS GOOD MODEL CONSENSUS AMONG THE 09.00Z RUNS OF A SLIGHT
SOUTHWARD SHIFT TO THE SURFACE LOW TRACK. THE RAP13 AND 00Z NAM
WERE THE FIRST TO SUGGEST THIS AND THE 00Z GFS CAME ALMOST
PERFECTLY IN LINE WITH THE NAM. WHAT IS A CONCERN IS THE ALMOST
IDENTICAL PLACEMENT OF 14-16" SNOWFALL IN THE WEST TWIN CITIES
METRO AND COUNTIES JUST WEST OF HERE. 09.00Z LOCAL WRF-ARW AND
09.08Z RAP ALSO HAVE HIGH END SNOWFALL RIGHT IN THE CENTER OF OUR CWA
GIVEN THE SLOW MOVEMENT AND TRACK OF THE SURFACE/850MB/700MB LOW
CENTERS. THE RAP HAS 20 INCHES...LIKELY OVERDONE BUT IT`S HINTING
AT THE POTENTIAL FOR SOMETHING SIGNIFICANT. THE PV FEATURE
ASSOCIATED WITH THIS SYSTEM IS IMPRESSIVE AND ITS ORIENTATION
SUGGESTS A LONGER THAN EXPECTED PERIOD OF SNOW TODAY. ALREADY
SEEING EVIDENCE OF A CIRCULATION IN THE REFLECTIVITY ACROSS SW
MN. THIS SHOULD FEATURE SHOULD LIFT NORTH...BECOME ANCHORED
PRODUCE 0.75-1.5" SNOWFALL RATES LATE THIS MORNING AND EARLY THIS
AFTERNOON. INCREASED THE SNOWFALL IN THE TWIN CITIES METRO TO 8-11
INCHES...AND HOPEFULLY THAT IS ENOUGH TO COVER IT. DEPTH OF SNOW
GROWTH REGION ISN`T OVERLY IMPRESSIVE...BUT WE SHOULD STILL MANAGE
SNOW RATIOS NEAR CLIMATOLOGY 13-14:1 OR SO. FURTHERMORE...ON THE
NOSE OF THE PV FEATURE...JUST AHEAD OF DRY SLOT...STATIC STABILITY
BECOMES WEAK AND SUGGESTS BANDED PRECIP COULD BE FACTORING IN TO
HELP SNOW TOTALS. OTHERWISE...WARMED TEMPS TONIGHT WITH THE SLOWER
PROGRESSION AND KEPT THE WIND ABOUT THE SAME...PERHAPS A BIT LESS.
THEREFORE WIND CHILLS AREN`T AS COLD WITH THIS MORNING`S FORECAST.
IN THE EXTENDED...HEIGHTS BEGIN TO BUILD BACK ON WEDNESDAY...SO
SHOULD ALREADY SEE MODERATING TEMPS FROM A COLD MONDAY AND
TUESDAY. A COUPLE WEAK CLIPPER SYSTEM LOOK TO PASS NORTH OF THE
AREA THIS WEEK...BUT THERE IS ANOTHER POTENTIALLY SIGNIFICANT
STORM ON THE HORIZON 6-7 DAYS FROM NOW.
&&
.AVIATION.../12Z TAF ISSUANCE/
OVER THE NEXT 6 HRS...CONDS WILL DETERIORATE RAPIDLY WITH MOST TAF
SITES GOING TO NEAR MINIMUMS. STORM SYSTEM WAS BEGINNING TO
DEVELOP A STRONG CIRCULATION NORTHWEST OF KFSD WITH A LARGE AREA
OF ENERGY THAT WILL LIFT TO THE E/NE DURING THE MORNING. SNOWFALL
RATES WILL LIKELY INCREASE TO 1...OR EVEN 2 INCHES PER HOUR DURING
THE HEIGHT OF THE STORM. TAFS ARE BASED ON CURRENT RAP MODEL SFC
WINDS AND FORECAST REFLECTIVITY OF THE SPC/WRF. AXN WILL LIKELY BE
ON THE NW SIDE OF THE LOWEST CIGS/VSBYS...WITH STC/RNH/MSP LIKELY
THE WORSE AREA DURING THE 15-03Z TIME FRAME. AS THE STORM SYSTEM
MOVES EASTWARD ACROSS SOUTHERN MN TODAY...EXPECT A BAND OF
MODERATE TO HEAVY SNOWFALL ALONG A LINE FROM KMVE TO KMGG TO KOEO.
AS THE STORM BEGINS TO PIVOT...EXPECT THE BANDS OF SNOW TO SLOWLY
MOVE FROM THE WEST TO THE EAST...THEN SE AS THE STORM MOVES OFF TO
THE WESTERN GREAT LAKES. THERE WILL BE A PERIOD OF 1/4SM +SN AND
VV002 OR LOWER. EXPECT SFC WINDS TO INCREASE AT AXN BY
15-18Z...THAN AT RWF BY 18-21Z. AFT 00-03Z CONDS WILL SLOWLY
IMPROVE WITH IFR...OR MVFR CIGS/VSBYS WITH BLSN CONTINUING
ACROSS AXN/RWF.
KMSP...
THERE IS A 3 HR PERIOD OF IFR/MVFR CONDS WITH -SN...BUT AFT 15Z
EXPECT CONDS TO DETERIORATE RAPIDLY WITH VSBYS DROPPING TO LESS
THAN 3/4SM AND CIGS LOWERING TO 500` OR EVEN LOWER. THERE IS A
PERIOD DURING THE AFTN WHERE VSBYS COULD DROP TO 1/4SM +SN AND
VV002. SFC WINDS WILL BE PREDOMINATE FROM THE E/SE THIS
MORNING/AFTN WITH SOME GUSTS OVER 20 KTS POSSIBLE BY MID MORNING.
WINDS WILL SHIFT TO THE E/NE AFT 21Z...THEN BECOME N/NNE BY 00-03Z
AND GUSTY. EVENTUALLY WINDS WILL SHIFT TO THE N/NNW AFT 06Z WITH
CIGS/VSBYS SLOWLY IMPROVING. DECIDED NOT TO INCLUDE A TEMPORARY
GROUP DUE TO UNCERTAINTIES OF TIMING OF WHEN THE WORSE CONDS
DEVELOP THIS MORNING/AFTN. TAFS WILL LIKELY BE AMD AS THIS SYSTEM
EVOLVES.
/OUTLOOK FOR KMSP/
MON...MVFR/IFR CIGS POSSIBLE EARLY. THEN VFR. WINDS WNW AT 10G15KTS.
TUE...MVFR/IFR CIGS POSSIBLE. FLURRIES. WINDS SW AT 10G15KTS.
WED...MVFR/IFR CIGS POSSIBLE EARLY. WINDS S AT 10KTS. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR ANOKA-BENTON-
CARVER-CHISAGO-DAKOTA-GOODHUE-HENNEPIN-ISANTI-KANABEC-LE
SUEUR-MILLE LACS-MORRISON-RAMSEY-RICE-SCOTT-SHERBURNE-
STEARNS-TODD-WASHINGTON-WRIGHT.
WINTER STORM WARNING UNTIL 11 AM CST THIS MORNING FOR CHIPPEWA-
DOUGLAS-KANDIYOHI-LAC QUI PARLE-MCLEOD-MEEKER-POPE-RENVILLE-
SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE.
BLIZZARD WARNING UNTIL MIDNIGHT CST TONIGHT FOR BROWN-CHIPPEWA-
DOUGLAS-KANDIYOHI-LAC QUI PARLE-MCLEOD-MEEKER-NICOLLET-POPE-
REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BLUE
EARTH-FARIBAULT-FREEBORN-MARTIN-STEELE-WASECA-WATONWAN.
WINTER WEATHER ADVISORY UNTIL 11 AM CST THIS MORNING FOR BROWN-
NICOLLET-REDWOOD.
WI...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BARRON-
CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
CLF/BORGHOFF
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
153 PM EST SUN DEC 9 2012
.SYNOPSIS...
A COLD FRONT FROM NEW ENGLAND TO THE TENNESSEE VALLEY WILL MOVE
SLOWLY SOUTHEAST TODAY BEFORE STALLING AND PUSHING BACK NORTH AS
WARM FRONT TONIGHT. A MUCH STRONGER COLD FRONT WILL CROSS THROUGH
THE AREA FROM THE WEST MONDAY EVENING. COOL HIGH PRESSURE WILL BUILD
IN BEHIND THE FRONT FOR TUESDAY INTO FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM EST SUNDAY...
LATEST SURFACE OBSERVATIONS INDICATE THE COLD FRONT IS SITUATED
JUST NORTHWEST OF OUR AREA THIS MORNING...STRETCHING THROUGH THE
CENTRAL PORTIONS OF KENTUCKY AND WEST VIRGINIA INTO NORTHERN
VIRGINIA. THE IMMEDIATE CONCERN IS A BAND OF SHOWER ACTIVITY
MAKING ITS WAY ACROSS KENTUCKY...RIDING ALONG THE FRONT. EXPECT
THESE SHOWERS TO SKIRT OUR MOUNTAIN EMPIRE COUNTIES BEGINNING
AROUND NOON...AND CONTINUE MOVING NORTHEAST ACROSS THE ALLEGHANY
HIGHLANDS THROUGH THE AFTERNOON BEFORE MOVING AWAY. SMALLER...MORE
SUBTLE DISTURBANCES PASSING ACROSS THE AREA WILL TRIGGER
SPOTTIER...LESS ORGANIZED SHOWER ACTIVITY ELSEWHERE THROUGH THE
DAY AS WELL.
AS THE DISTURBANCE TRIGGERING THESE SHOWERS MOVES NORTH...IT WILL
HELP PUSH THE COLD FRONT SOUTH INTO THE FOOTHILLS. OUR LOCAL WRF
AND RAP FORECAST MODELS INDICATED THE WEDGE REACHING THE ROANOKE
RIVER BY THE END OF THE DAY...BEFORE ADVANCING SLOWLY BACK NORTH
TONIGHT AS A WARM FRONT.
HAVE MORE CLOUD COVER AND COOLER TEMPERATURES NORTH OF THE FRONT
TODAY AND MORE FOG OVERNIGHT TONIGHT. USED A NON DIURNAL TREND FOR
HOURLY TEMPERATURES OVERNIGHT. THOSE LOCATIONS THAT PULL OUT OF
THE WEDGE WILL LIKELY WARM UP AS THEY GET BACK INTO THE WARM
SECTOR.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 330 AM EST SUNDAY...
PRIMARY FOCUS FOR THE SHORT TERM FORECAST WAS ON THE TIMING OF THE
COLD FRONT MOVING THROUGH THE FORECAST AREA LATE MONDAY AND MONDAY
NIGHT. WITH SFC WAVES RIDING UP THE SFC BOUNDARY AND
INITIAL UPPER LEVEL SHORTWAVE LIFTING NORTH WITH MORE
ENERGY DIGGING INTO THE BASE OF THE UPPER LEVEL TROF IN THE CENTRAL
U.S....CONTINUED TO LEAN TOWARD THE SLOWER MODEL SOLUTIONS.
FOR THIS FORECAST PACKAGE...THE SLOWER NAM AND SREF WERE
PREFERRED.
AS WINDS VEER IN RESPONSE TO THE APPROACH OF THE UPPER LEVEL
TROF...SFC WEDGE SHOULD HAVE ERODED BY 12Z MONDAY...OR SHORTLY
THEREAFTER...LEAVING THE ENTIRE FORECAST FIRMLY ENTRENCHED IN THE
WARM SECTOR. A DEEP SOUTHWEST FLOW ALONG WITH SOME BREAKS IN THE
CLOUDS IN THE EAST SHOULD ALLOW TEMPS TO SOAR WELL ABOVE
NORMAL...BUT STILL BELOW RECORDS FOR 12/10.
BEST 850-300MB OMEGA PER THE NAM ARRIVES IN THE WEST AROUND 18Z
MONDAY...BUT LIFTS TO THE NORTH AFTERWARDS WITH UPPER LEVEL
SHORTWAVE. THIS LEAVES UNCERTAINTY ON HOW FAR EAST PRECIPITATION
SHIELD CAN TRAVEL. AS A RESULT...KEPT MUCH HIGHER POPS IN THE
MOUNTAINS...WITH HIGH CHANCE POPS IN THE EAST LATE MONDAY AND MONDAY
NIGHT.
NAM FORECAST SOUNDINGS INDICATE THE LOWER LEVEL OF THE ATMOSPHERE
BEGINS DRYING WHEN TEMPS COLD ENOUGH FOR SNOW BEGINS TO ARRIVE
ALONG THE WESTERN SLOPES. MAY STILL BE ABLE TO SQUEEZE OUT SOME
LIGHT SNOW SHOWERS IN THE HIGHEST ELEVATIONS OF SOUTHEAST
WV/ALLEGHANY HIGHS FOR A FEW HOURS TUESDAY MORNING.
EVEN THE SLOWEST SREF KEEPS SFC BOUNDARY WELL SOUTHEAST OF THE
FORECAST AREA ON TUESDAY. WEAK SFC WAVES MOVING THROUGH EASTERN
NC/VA ON TUESDAY WILL KEEP SOME CLOUDS IN THE FAR EAST...BUT LOW
LEVEL NORTHWEST WINDS WILL KEEP THE FORECAST AREA DRY BY 18Z.
AS SFC RIDGE QUICKLY BUILDS OVER THE AREA TUESDAY...COLD AIR
ADVECTION DIMINISHES DURING THE DAY AND EXPECT TEMPS TO RECOVER AND
USED A BLEND OF THE NAM/GFS MOS GUIDANCE FOR HIGHS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 330 PM EST SATURDAY...
HIGH PRESSURE WILL CONTROL THE WEATHER PATTERN THROUGH FRIDAY. WILL
BE KEEPING AN EYE ON A LOW PRESSURE SYSTEM DEVELOPING ALONG THE
CAROLINA COAST OF WEDNESDAY/THURSDAY TO SEE IF ANY SHOWER ACTIVITY
ADVANCES INTO THE PIEDMONTS...BUT BECOMING MORE CONFIDENT THAT THIS
ACTIVITY WILL STAY EAST OF THE AREA. THE NEXT BIG STORM SYSTEM TO
WATCH WILL ARRIVE NEXT WEEKEND AS A DEEP LOW PRESSURE SYSTEM PASSES
EASTWARD FROM THE CENTRAL PLAINS INTO THE GREAT LAKES...DRAGGING A
COLD FRONT TOWARD OUR AREA.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 130 PM EST SUNDAY...
SURFACE OBSERVATIONS INDICATE THAT WHILE VISIBILITIES HAVE
IMPROVED WITH AFTERNOON HEATING...AREAS OF LIFR TO MVFR CEILINGS
REMAIN ACROSS THE AREA...INTERMIXED WITH VFR CEILINGS. ALSO
CONCERNED WITH TWO AREAS OF SHOWER ACTIVITY...A SMALL AREA THAT
WILL BRIEFLY AFFECT DAN BETWEEN 19Z AND 21Z...AND A MUCH LARGER
AREA STRETCHING FROM EASTERN TENNESSEE THROUGH NORTHERN WEST
VIRGINIA...MOVING TO THE NORTHEAST ALONG A COLD FRONT SITUATED
ACROSS THE AREA. EAST OF THE MOUNTAINS...ALSO OBSERVING THE SAME
COLD FRONT BUILD SOUTHWARD ACROSS THE PIEDMONTS AS A BACKDOOR
FRONT...ALREADY HAVING PASSED THROUGH LYH...AS EVIDENCED BY MVFR
STRATOCU MOVING IN FROM THE NORTHEAST.
WHILE THE MAJORITY OF THE SHOWER ACTIVITY WILL REMAIN WEST OF THE
AREA THIS AFTERNOON...EXPECT SOME OF THESE SHOWERS TO SPILL OVER
THE MOUNTAINS...AFFECTING BLF AND LWB DURING EARLY TO MID
EVENING...BEFORE PUSHING AWAY FROM THE AREA BEFORE MIDNIGHT
MONDAY.
EXPECT MVFR FOG MOST LOCATIONS AGAIN TONIGHT. DEPENDS ON HOW FAR
THE BACKDOOR FRONT ADVANCES WEST...EVEN ROA MAY HAVE MVFR FOG.
ALSO CONCERNED WITH LOW LEVEL WIND SHEAR DUE TO STRENGTHENING LOW
LEVEL JET. MODELS HAVE WINDS JUST ABOVE THE SURFACE FROM THE
SOUTHWEST AT 30 TO 40 KNOTS...AND HAVE THEREFORE MENTIONED IN THE
TAFS. EXPECT THE BACKDOOR FRONT TO LIFT NORTHWARD AGAIN SHORTLY
BEFORE SUNRISE AS A DEEP LOW PRESSURE SYSTEM PASSES ACROSS THE
GREAT LAKES.
ON MONDAY AFTERNOON...A STRONG COLD FRONT WILL ENTER THE FORECAST
AREA...PASSING ACROSS BLF AND LWB AOA 10/20Z...AND MOVING ACROSS
DAN AND LYH AOA 11/03Z. EXPECT GUSTY NORTHWEST WINDS BEHIND THE
FRONT ON MONDAY NIGHT AND TUESDAY.
CONDITIONS WILL IMPROVE ON TUESDAY EVENING AS HIGH PRESSURE
BEGINS TO SETTLE ACROSS THE AREA. LINGERING MOISTURE IN THE
MOUNTAINS TUESDAY WILL RESULT IN MVFR CONDITIONS AND THE
POSSIBILITY OF SNOW SHOWERS AS COLDER AIR SURGES INTO THE AREA.
VFR CONDITIONS WILL RETURN FOR TUESDAY NIGHT THROUGH FRIDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/NF
SHORT TERM...PH
LONG TERM...NF
AVIATION...AMS/NF