Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/18/14
AREA FORECAST DISCUSSION
NWS EUREKA CA
354 PM PST WED DEC 17 2014
.SYNOPSIS...PERSISTING RAIN SHOWERS WILL DIMINISH OVERNIGHT. THEN
BUILDING HIGH PRESSURE WILL RESULT IN A MOSTLY DRY DAY ON
THURSDAY. AN APPROACHING COLD FRONT WILL BRING THE NEXT
OPPORTUNITY FOR RAIN LATE THURSDAY NIGHT THROUGH FRIDAY MORNING.
&&
.SHORT TERM...(TODAY THRU THURSDAY) A WEAK DISTURBANCE HAS PROLONGED
VERY LIGHT SHOWER ACTIVITY TODAY FOR MOSTLY AREAS NORTH OF CAPE
MENDOCINO. THE 23Z RADAR IMAGERY SHOWS LIGHT TO MODERATE RAIN
OFFSHORE MAKING ITS WAY ONSHORE. THE APPROACHING SURFACE LOW WILL
BRING ONE LAST SHOT OF RAIN THIS EVENING AS IT SLIDES PAST THE NW
CALIFORNIA COAST. ADDITIONAL RAINFALL THROUGH TONIGHT WILL BE ON
THE LIGHTER SIDE AMOUNTING TO AROUND ONE QUARTER INCH. SNOWFALL
WITH THE LINGERING SHOWERS WILL NOT POSE A MAJOR CONCERN THIS
EVENING AS PRECIPITATION WILL BE LIGHT AND SNOW LEVELS ARE
FORECAST TO GRADUALLY INCREASE OVERNIGHT.
500MB HEIGHTS WILL GRADUALLY BUILD OVERNIGHT INTO THURSDAY AS A WEAK
UPPER LEVEL RIDGE SHIFTS OVER THE WEST COAST OF THE UNITED STATES.
THIS SHOULD RESULT IN MOSTLY DRY WEATHER EARLY IN THE DAY, HOWEVER,
MOISTURE STREAMING OVER THE RIDGE COULD RESULT SOME LIGHT SPRINKLES
THROUGH THE DAY. THEN, A BOUNDARY ASSOCIATED WITH AN UPPER LEVEL LOW
LOCATED OFF OF THE COAST OF BRITISH COLUMBIA WILL APPROACH NORTHWEST
CALIFORNIA THURSDAY EVENING. RECENT MODEL RUNS HAVE SPED UP THE
ARRIVAL OF THE RAIN TO THURSDAY EVENING BUT STILL REMAIN IN DECENT
AGREEMENT WITH ONE ANOTHER. RAINFALL CAN BE HEAVY AT TIMES WITH MOST
AREAS LOOKING AT 0.75 INCHES OVERNIGHT AND HIGHER TERRAIN ACROSS
FAVORABLE AREAS GETTING AS MUCH AS 1.5 INCHES. SNOWLEVELS WILL
REMAIN AROUND 5000 FEET AS MOST OF THE PRECIPITATION FALLS BUT
WILL DECREASE INTO THE MORNING. FLURRIES MAY BE OBSERVED AT SOME
MOUNTAIN PASSES HOWEVER SNOWFALL SHOULD MOSTLY BE RESTRICTED TO
THE TRINITY ALPS WITH THE PASS ON HIGHWAY 3 SOUTH OF CALLAHAN
SEEING POTENTIAL IMPACTS.
.LONGTERM...(FRIDAY THRU WED) SHOWERS WILL DIMINISH FRIDAY RESULTING
IN A MOSTLY DRY DAY HOWEVER THE WET PATTERN CONTINUES SATURDAY AND
AGAIN SUNDAY AS FLOW BECOMES MORE ZONAL. THE LONGWAVE MODEL HINTS
TOWARDS THE DEVELOPMENT OF A LONGWAVE RIDGE ACROSS THE WESTERN
UNITED STATES THIS WEEKEND. I FEAR MODELS MAY POTENTIALLY BE OVER
DOING THE PRECIPITATION FOR THIS WEEKEND BUT MADE LITTLE TO NO
CHANGES DUE TO UNCERTAINTY. STRONGER RIDGING WILL BUILD OVER THE
EASTERN PACIFIC EARLY NEXT WEEK BRINGING WARMER TEMPERATURES AND
DRIER WEATHER THROUGH THE MIDDLE OF THE WEEK. BOTH THE GFS AND ECMWF
HINT AT ANOTHER TROUGH FOR LATE NEXT WEEK BUT DIFFER IN THE
STRENGTH. AGAIN FEW CHANGES WERE MADE TO THE LONG TERM AND CLIMO
POPS WERE USED FOR THE TAIL END OF THE FORECAST. KML
&&
.AVIATION...A WEAKENING LOW PRESSURE SYSTEM OFFSHORE WILL PROVIDE
MORE PERIODS OF LIGHT TO MODERATE RAIN AS WELL AS OCCASIONAL MVFR
CONDITIONS TONIGHT. LINGERING MOIST AIR WILL MAKE IFR CIGS AND VSBYS
POSSIBLE AT UKIAH AND OTHER VALLEYS IN THE INTERIOR BY EARLY THU
MORNING. CONDITIONS SHOULD IMPROVE TO VFR THROUGH THE DAY ON THU.
&&
.MARINE...WINDS HAVE TURNED SOUTHERLY IN ADVANCE OF A WEAKENING LOW
APPROACHING THE WATERS. SHIP REPORTS SHOWED WINDS AROUND 15-20 KT
WHICH SEEMED TO MATCH BETTER WITH THE GFS...HI-RES-NMM AND HRRR. THE
SREF AND NAM12 LOOKED UNDERDONE. BOTH THE HIRES-NMM AND HRRR SHOW A
RIBBON OF 20-25KT IN THE OUTER WATERS AND AROUND CAPE MENDO THROUGH
THIS EVENING. ALSO SEAS HAVE BEEN RUNNING 2 TO 3 FT ABOVE THE MODEL
GUIDANCE THROUGH THE DAY. MOST OF THIS WAVE ENERGY HAS BEEN COMING
FROM 280-290 DEGREES. THUS EXTENDED THE SMALL CRAFT ADVISORY THROUGH
TONIGHT. THE MODELS CONTINUE TO SHOW THE WESTERLY SWELL TRENDING
DOWNWARD ON THURSDAY INTO THURSDAY NIGHT AS A STRONGER FRONTAL
SYSTEM APPROACHES THE WATERS THROUGH THE DAY. SOUTHERLY WINDS WILL
START TO RAMP BACK UP TO SMALL CRAFT LEVELS OF 20-25 KT BY THURSDAY
EVENING. THE MODELS TEND TO BE TOO SLOW WITH WINDS INCREASING...SO
THE ADVISORY HAS BEEN EXTENDED INTO THU AND THU NIGHT. THE FRONT
WILL MOVE INLAND BY FRI MORNING LEAVING MUCH LIGHTER WINDS IN ITS
WAKE.
A HURRICANE FORCE LOW CURRENTLY SOUTH OF THE ALEUTIAN ISLANDS WILL
PRODUCE A LARGE SWELL WHICH WILL PROPAGATE TOWARD THE NORCAL COAST
AND ARRIVE ON FRIDAY. ASCAT PASS SHOWED 50-55KT IN THE SOUTHERN HALF
OF THE LOW. THIS AGREES QUITE WELL WITH THE WAVE WATCH III WINDS.
CONFIDENCE IS INCREASING A LARGE WESTERLY SWELL WILL HIT THE
NORTHERN CAL COAST ON FRI. THE EXACT MAGNITUDE OF THE SWELL WILL BE
MUCH MORE CERTAIN WHEN THE SWELL GOES BY THE OFFSHORE BUOYS; BUOY #2
250NM WEST OF BLANCO WHICH IS THE ONLY ONE LEFT.
FOR NOW HAVE STAYED CLOSED TO THE MODEL GUIDANCE WHICH HAS THE SWELL
PEAKING AROUND 17 TO 19 FT AT 18 SECONDS FRIDAY NIGHT. BREAKERS
AROUND 25 FEET WILL BE POSSIBLE FRIDAY NIGHT. JASON-2 ALTIMETRY
MEASUREMENTS THUS FAR HAS CAPTURED ONLY THE SIDES OF THE WAVE MAX.
HOPEFULLY WE GET A PASS RIGHT OVER THE CENTER TO CONFIRM THE WAVE
HEIGHTS IN THE NEXT 12 HOURS. A MARINE WEATHER STATEMENT HAS BEEN
ISSUED TO CALL ATTENTION TO THIS LARGE SWELL EVENT WHICH SHOULD
PRODUCE HAZARDOUS SURF CONDITIONS.
IN ADDITION...FORERUNNERS WILL BRING A POTENTIAL FOR SNEAKER WAVES
DURING THE DAY ON FRIDAY. LOOKING AT THE SEA STATE SPECTRUM THERE
WILL BE ANOTHER WESTERLY WAVE GROUP PRESENT...8-10 FT AROUND 13
SECONDS ON FRIDAY. THE SHORTER PERIOD SOUTHERLY WAVE GROUP SHOULD BE
NEGLIGIBLE. CONFIDENCE IT NOT HIGH THAT ALL OF THE VARIABLES WILL
COME TOGETHER HERE FOR THIS TO BE A HIGH END THREAT FOR SNEAKER
WAVES.
THE SWELL WILL SUBSIDE OVER THE WEEKEND. A WARM FRONT WILL APPROACH
THE WATERS ON SATURDAY INTO SATURDAY NIGHT BRINGING ANOTHER PERIOD
OF SMALL CRAFT ADVISORY SOUTHERLY WINDS.
&&
.COASTAL FLOOD...PERSISTENT SOUTHERLY WINDS CONTINUE TO KEEP WATER
LEVELS ABOVE THE ASTRONOMICAL TIDES BY 1 TO 2 FT. THE ASTRONOMICAL
TIDES ARE NEARLY 8 FT IN HUMBOLDT BAY ON SATURDAY AND 8.1 FT ON
SUNDAY. DEPENDING ON HOW PERSISTENT THE SOUTHERLY WINDS ARE...THIS
COULD CAUSE SOME COASTAL FLOODING IN THE LOW LYING AREAS AROUND
HUMBOLDT BAY. IN ADDITION, WITH THESE HIGH WATER LEVELS THE HIGH
SURF MAY PUSH WATER UP HIGHER IN EXPOSED COASTAL AREAS. MKK
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 3 PM PST THURSDAY FOR PZZ450-455.
SMALL CRAFT ADVISORY UNTIL 3 PM PST FRIDAY FOR PZZ470-475.
&&
$$
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AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
1100 AM PST Tue Dec 16 2014
.Synopsis...
Periods of valley rain and mountain snow through mid-week as
several weather systems move through the area. Brief drying
expected Thursday, then another system is forecast to bring a
return of showers on Friday.
&&
.Discussion...
Winter Wx Advsry will be allowed to expire at noon as this current
system is winding down. The next system is on our doorstep just off
the coast and will be gradually moving inland tonite. Jet energy
remains off the coast and is digging the trof so Ewd movement of the
system may be a little slower than forecast earlier. The HRRR/WRF
show the couple hour disparity in timing with the HRRR slower.
Will likely issue another WSW and working on the timing details now.
JHM
.Previous Discussion...
The reak in showers we see today will be short-lived as another
system arrives later today and tonight spreading more rain and snow
across NorCal along with bringing gusty southerly winds. That one
exits east by early Wednesday, then another moves in later
Wednesday. Following a break Thursday as short-wave ridging moves
overhead, another system is forecast to move in on Friday.
Total additional QPF through mid-week of 1/3-3/4`s of an inch of
rain can be expected in the valley with 1-2 inches in the
foothills and mountains. Snow levels will be moderately low during
the period generally ranging from 3000-4000 feet. 48 hour snow
accumulations of a foot or more will be possible at the higher
elevations with 4-8 inches possible down to around 4000-5000 feet.
This will lead to travel impacts over the mountains with delays
possible at times with chain requirements.
&&
.Extended Discussion (Saturday through Tuesday)...
The Friday system moves through the area, but showers linger over
mountains on Saturday. The GFS, EC, and GEM depict a 590-591 dm
high center over the eastern Pacific Sunday leaving only slight
chances of precip over the Shasta mountains. The high drifts near
the SoCal coast Monday into Tuesday, drying out the region with
significant southern Sac and northern San Joaquin Valley fog
setting up.
GFS and EC flatten the ridge somewhat Tuesday, and the GEM
actually introduces a trough just offshore. Since all models
trended to at least a flattening/weakening of the ridge, we
introduced a slight potential of light rain over Shasta mountains
Tuesday afternoon. JClapp
&&
.Aviation...
Scattered showers cont this morning with freezing levels ranging
around 3000-3500 ft MSL in Shasta County to 5000-5500 ft MSL near
I-80/hwy 50. IFR cigs at northern valley TAF sites til near 20z
from -SHRA and/or BR. Another system moves in late this afternoon
and/or early evening for continued periods of precip. JClapp
&&
.STO Watches/Warnings/Advisories...None.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
957 AM PST TUE DEC 16 2014
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST ACROSS SW CA THIS MORNING AND DEVELOP
RAIN SHOWERS AND HIGH ELEVATION SNOW TODAY..WITH A SLIGHT CHANCE
OF THUNDERSTORMS. A SECOND...STRONGER FRONT WILL CREATE MORE
WIDESPREAD SHOWERS TONIGHT THROUGH THURSDAY MORNING...ESPECIALLY
WEDNESDAY MORNING. SNOW LEVELS WILL DROP TO BETWEEN 5000 TO 6000
FEET WEDNESDAY. SEVERAL INCHES OF SNOW ARE EXPECTED ABOVE 6000
FEET. DRY WITH A WARMING TREND THURSDAY AFTERNOON THROUGH FRIDAY.
A WEAK TROUGH MAY PRODUCE ISOLATED LIGHT SHOWERS ON SATURDAY.
WARMER AGAIN WITH DRY OFFSHORE FLOW EARLY NEXT WEEK.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
AT 9 AM PST...WATER VAPOR SATELLITE IMAGERY DISPLAYED A WEAK COLD
FRONT MOVING EAST ACROSS THE SOUTHERN CA BIGHT...AND A TROUGH OFF
OF THE WEST COAST. COMPOSITE RADAR SHOWED LIGHT TO MODERATE
SHOWERS OVER THE COASTAL WATERS...AND OVER PORTIONS OF THE COAST
AND VALLEYS. LIGHT TO MODERATE RAIN AND HIGH ELEVATION MOUNTAIN
SNOW IS FORECAST TODAY ACROSS THE REGION AS THE FRONT MOVES EAST.
MOST UNSTABLE CAPE OF 400-600 J/KG WILL CREATE THE POSSIBILITY OF
ISOLATED THUNDERSTORMS WEST OF THE MOUNTAINS THROUGH THIS EVENING.
A WINTER WEATHER ADVISORY REMAINS IN EFFECT THROUGH THIS EVENING
FOR THE SAN BERNARDINO COUNTY MOUNTAINS ABOVE 6000 FT.
...PRECIPITATION ACCUMULATIONS TODAY...
DESERTS.........ONE-TENTH TO ONE-QUARTER IN
COAST/VALLEYS...ONE-QUARTER TO ONE-HALF IN
MOUNTAINS.......ONE-HALF TO THREE-QUARTERS IN
...SNOWFALL ACCUMULATIONS TODAY...
SAN BERNARDINO COUNTY MOUNTAINS ABOVE 6000 FT...1 TO 3 IN
RIVERSIDE COUNTY MOUNTAINS ABOVE 7000 FT......1 TO 2 IN
A SECOND...STRONGER FRONT...WILL MOVE ACROSS THE AREA TONIGHT
THROUGH THURSDAY MORNING...AND GENERATE MORE WIDESPREAD SHOWERS
AND MOUNTAIN SNOW...ESPECIALLY WEDNESDAY MORNING. ISOLATED
THUNDERSTORMS WILL BE POSSIBLE AGAIN AS ELEVATED INSTABILITY
REDEVELOPS OVER SW CA. BREEZY WEST TO SOUTHWEST WINDS WILL ALSO
DEVELOP OVER MOUNTAIN RIDGES AND THROUGH PASSES WEDNESDAY AS THE
FRONT PASSES...WITH GUSTS TO 45 MPH POSSIBLE.
...PRECIPITATION ACCUMULATIONS TONIGHT THROUGH THU AM...
DESERTS.....ONE-QUARTER TO ONE-HALF IN
COAST.......ONE-HALF TO ONE IN
VALLEYS.....THREE-QUARTERS TO ONE AND ONE-HALF IN
MOUNTAINS...ONE TO TWO IN
...SNOWFALL ACCUMULATIONS TONIGHT THROUGH THU AM FOR SAN BERNARDINO...
RIVERSIDE AND SAN DIEGO COUNTY MOUNTAINS...
5000-6500 FT...TRACE TO 4 IN
6500-8000 FT...4 TO 8 IN...WITH LOCALLY HIGHER AMOUNTS ABOVE 8000 FT
SEE LAXWSWSGX FOR DETAILS ON THE WINTER WEATHER ADVISORIES AND
WINTER STORM WATCH CURRENTLY IN EFFECT. MODERATE TO HEAVY
RAINFALL IN SHOWERS WILL CREATE THE POSSIBILITY OF FLASH FLOODING
AND DEBRIS FLOW OVER RECENT BURN SCARS...ESPECIALLY THE SILVERADO
AND MOUNTAIN SCARS. A FLASH FLOOD WATCH REMAINS IN EFFECT FOR
THOSE AREAS FROM THIS AFTERNOON THROUGH WEDNESDAY AFTERNOON. HIGHS
5 TO 10 DEGREES BELOW NORMAL WILL CONTINUE ACROSS THE REGION
THROUGH THURSDAY.
WEAK UPPER-LEVEL HIGH PRESSURE WILL BUILD OVER THE AREA LATE
THURSDAY AND FRIDAY...KEEPING THE WEATHER DRY AND RAISING HIGHS TO
ONLY AROUND 5 DEGREES F ABOVE NORMAL. A SHORT-WAVE TROUGH WILL
QUICKLY SWING ACROSS THE AREA SATURDAY MORNING. A SLIGHT CHANCE OF
SHOWERS IS FORECAST. HOWEVER...PRECIPITABLE WATER OF AROUND THREE-
QUARTERS INCH AND WEAK INSTABILITY ALOFT WILL LIMIT MUCH SHOWER
DEVELOPMENT. HIGH PRESSURE WILL THEN REBUILD OFF THE WEST COAST
EARLY NEXT WEEK...WHICH WILL SLOWLY INCREASE HIGH TEMPERATURES TO
AROUND 10 DEGREES F ABOVE NORMAL BY NEXT TUESDAY...WITH WEAK
OFFSHORE FLOW DEVELOPING AND A MORE SHALLOW MARINE LAYER.
&&
.AVIATION...
161644Z...MULTIPLE BKN-OVC CLOUD DECKS IN THE 2500-10000 FT MSL
LAYER WITH INCREASING SHOWERS...LOCAL VIS AOB 2SM IN RA/+RA...AND
MOUNTAIN OBSCURATION ABOVE 2500 FT MSL THROUGH 17/0900 UTC MAINLY
OVER AND WEST OF THE MOUNTAINS. ISOL THUNDERSTORMS POSSIBLE STARTING
1800 UTC...WITH CB TOPS TO 30000 FT MSL...SMALL HAIL...HEAVY
RAIN...LOCAL VIS BELOW 1 SM...AND GUSTY DOWNDRAFT WINDS POSSIBLE.
DESERTS WILL HAVE MOSTLY UNRESTRICTED VIS AND BKN-OVC CLOUDS AOA
12000 FT MSL. 17/0900-1800 UTC...SHOWERS INCREASING SIGNIFICANTLY IN
COVERAGE AND INTENSITY...MAINLY OVER AND WEST OF THE MOUNTAINS AND
OVER THE HIGH DESERTS...WITH BKN-OVC CLOUDS IN THE 1500-15000 FT MSL
LAYER...AREAS OF 2-5 SM VIS...LOCAL VIS 1 SM OR LESS...MOUNTAIN
OBSCURATION ABOVE 1500 FT MSL...AND POSSIBLE THUNDERSTORMS. COASTAL
TAF SITES LIKELY TO GET HEAVIEST RAIN AND LOWEST VIS/CIGS IN THE
17/1100-1600 UTC TIME-FRAME. LOWER DESERTS LIKELY TO GET SOME
SHOWERS AFTER 17/1200 UTC WITH LOCAL CIGS/VIS 2500 FT AGL/5 SM.
OTHERWISE...LOWER DESERTS WILL HAVE BKN-OVC CLOUDS IN THE 7000-13000
FT MSL LAYER.
&&
.MARINE...
933 AM...SOUTHERLY WINDS HAVE PICKED UP AT THE SAN CLEMENTE BASIN
BUOY OVER THE PAST SEVERAL HOURS...WHICH THE HRRR MODEL SEEM TO PICK
UP ON BETTER THAN THE OTHER HIGH-RES MODELS. THUS...THE COASTAL
WATERS FORECAST WAS UPDATED AT 8 AM TO REFLECT THE STRONGER WINDS
TODAY AS A WEAK COLD FRONT MOVES THROUGH. A MUCH STRONGER FRONT
ARRIVES EARLY WEDNESDAY MORNING WITH STRONG SOUTHWEST WINDS TURNING
NORTHWEST BY LATE WEDNESDAY MORNING. ALSO...SEAS FROM THE EXPECTED
WEST-NORTHWEST SWELL HAVE JUMPED UP TO NEAR 10 FEET FINALLY. THE
SWELL WILL PEAK TODAY...WITH COMBINED SEAS NEAR OR ABOVE 10 FEET
THROUGH WEDNESDAY MORNING...BEFORE LOWERING DURING THE REST OF
WEDNESDAY. SEE THE SMALL CRAFT ADVISORY FOR DETAILS...LAXMWWSGX.
THESE COLD FRONTS WILL ALSO BRING INCREASED INSTABILITY...STARTING
THIS MORNING AND CONTINUING THROUGH WEDNESDAY AFTERNOON...WITH
THUNDERSTORMS MOST LIKELY TO OCCUR WEDNESDAY MORNING. THESE
THUNDERSTORMS ARE CAPABLE OF PRODUCING WATERSPOUTS AND STRONG GUSTY
WINDS. SEE THE MARINE WEATHER STATEMENT FOR DETAILS...LAXMWSSGX.
&&
.BEACHES...
844 AM...LATEST OBSERVATIONS AT THE SAN CLEMENTE BASIN BUOY SHOWED
THE SWELL JUMPING UP TO 10 FEET AT 17 SECONDS...WITH NEARSHORE BUOYS
HAVING JUMPED TO 4 TO 6 FEET. DUE TO THE LOWER SWELL HEIGHTS THAN
CURRENTLY FORECAST BY THE WAVE WATCH 3...SURF HEIGHTS MAY BE A
LITTLE LOWER THAN PREVIOUSLY FORECAST...POSSIBLY AROUND 5 TO 8 FEET
WITH LOCAL 10 FOOT SETS. HOWEVER...IF THE LATEST BUOY OBSERVATIONS
ARE ANY INDICATION...THE SWELL MAY JUST BE LATE TO ARRIVE AND SURF
OF 6 TO 10 FEET AND LOCAL 12 FOOT SETS COULD STILL OCCUR. THE LARGE
WEST-NORTHWEST SWELL WILL PEAK TODAY AND BRING HIGH SURF AND STRONG
RIP CURRENTS TO AREA BEACHES. THE SURF WILL SLOWLY SUBSIDE LATE
TONIGHT THROUGH WEDNESDAY. A HIGH SURF ADVISORY REMAINS IN EFFECT
THROUGH WEDNESDAY MORNING. SEE THE HIGH SURF ADVISORY FOR THE SURF
DETAILS...LAXCFWSGX.
&&
.SKYWARN...
SKYWARN ACTIVATION MAY BE REQUESTED THIS AFTERNOON THROUGH
WEDNESDAY DUE TO POTENTIALLY HEAVY RAIN AND ISOLATED THUNDERSTORMS.
WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS TO THE NATIONAL WEATHER SERVICE.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...HIGH SURF ADVISORY UNTIL NOON PST WEDNESDAY FOR THE BEACHES
IN THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO COUNTY COASTAL
AREAS.
WINTER WEATHER ADVISORY UNTIL 6 PM PST THIS EVENING ABOVE 6000
FEET FOR THE SAN BERNARDINO COUNTY MOUNTAINS.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH WEDNESDAY AFTERNOON
ABOVE 5500 FEET FOR THE SAN BERNARDINO COUNTY MOUNTAINS.
FLASH FLOOD WATCH FROM NOON PST TODAY THROUGH WEDNESDAY
AFTERNOON FOR THE RIVERSIDE COUNTY MOUNTAINS...SANTA ANA
MOUNTAINS AND FOOTHILLS.
WINTER WEATHER ADVISORY FROM 6 AM TO 8 PM PST WEDNESDAY FOR THE
RIVERSIDE COUNTY MOUNTAINS...SAN DIEGO COUNTY MOUNTAINS.
PZ...SMALL CRAFT ADVISORY UNTIL 10 PM PST WEDNESDAY FOR THE BEACHES
IN THE COASTAL WATERS FROM SAN MATEO POINT TO THE MEXICAN
BORDER AND OUT 30 NM...WATERS FROM SAN MATEO POINT TO THE
MEXICAN BORDER EXTENDING 30 TO 60 NM OUT INCLUDING SAN
CLEMENTE ISLAND.
&&
$$
PUBLIC...JJT
AVIATION/MARINE/BEACHES...HARRISON
RADAR...PG
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
410 AM PST TUE DEC 16 2014
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE COAST THIS MORNING AND SPREAD RAIN
SHOWERS ALONG THE COAST...PUSHING INLAND THIS AFTERNOON. THERE
WILL ALSO BE A SLIGHT CHANCE OF THUNDERSTORMS. ACCUMULATING SNOW
WILL BE POSSIBLE IN THE HIGH MOUNTAINS. A SECOND...STRONGER STORM
WILL BRING MORE SHOWERS ON WEDNESDAY...HEAVY AT TIMES. THE SECOND
STORM WILL ALSO FILTER IN SOME COOLER AIR AND LOWER SNOW LEVELS TO
BETWEEN 5000 TO 6000 FEET WEDNESDAY. SEVERAL INCHES OF SNOW ARE
EXPECTED ABOVE 6000 FEET. DRY WITH A WARMING TREND THURSDAY
AFTERNOON THROUGH FRIDAY. A WEAK TROUGH MAY PRODUCE SCATTERED
LIGHT SHOWERS ON SATURDAY. WARMER AGAIN WITH DRY OFFSHORE FLOW
EARLY NEXT WEEK.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
WELL...SHOWERS OFFSHORE PETERED OUT AROUND MIDNIGHT BEFORE THEY
MADE IT TO THE COASTLINE. HOWEVER ANOTHER BATCH OF RAIN SHOWERS
ARE BECOMING EVIDENT ON RADAR AND SATELLITE WELL OFFSHORE...SOUTH
OF SAN CLEMENTE ISLAND...AND ARE EXPECTED TO MOVE TO JUST OFFSHORE
AFTER DAYBREAK THIS MORNING...COINCIDENT WITH A DECAYING COLD
FRONT. THESE SHOWERS MAY BECOME BETTER ORGANIZED TOWARDS MIDDAY
WITH A BIT OF DIURNAL HEATING MOVING ONTO THE COAST AND SPREAD
INLAND TO THE MOUNTAINS. THE HIGH RESOLUTION WRF AND ESPECIALLY
THE HRRR BOTH INDICATE A THIN BAND OF SURFACE INSTABILITY (CAPE
VALUES AS HIGH AS 1000 J/KG) BETWEEN 18Z-00Z. NOT SURE HOW FAR
INLAND THIS BAND WILL MAKE IT BUT FOR NOW INDICATED SLIGHT CHANCE
OF THUNDERSTORMS ALL THE WAY TO THE INLAND MOUNTAINS. BRIEF HEAVY
BURSTS OF RAIN MOST LIKELY THIS AFTERNOON WITH ANY STRONGER CELLS
THAT DO FORM...THEREFORE WILL CONTINUE THE FLASH FLOOD WATCH WHICH
BECOMES IN FORCE THIS AFTERNOON THROUGH WEDNESDAY AFTN.
AFTER 00Z THE COLD FRONT WILL LIKELY WASH OUT INLAND AND SHOWERS
WILL DIMINISH IF NOT DISSIPATE EXCEPT FOR SOME LINGERING SHOWERS
IN THE MOUNTAINS THROUGH THE EVENING.
A STRONGER SYSTEM WITH A SURFACE LOW PRESSURE WAVE IS EXPECTED TO
APPROACH OUR REGION EARLY WEDNESDAY MORNING FROM THE NW. THIS
FEATURE IS STILL EXPECTED TO BRING MORE WIDESPREAD PRECIPITATION
ALONG WITH A BIT OF COLDER AIR TO THE MOUNTAINS. THE LATEST MODELS
ARE NOT QUITE AS STRONG WITH THE COLDER AIR BUT WITH CONVECTION
WEDNESDAY AFTERNOON COULD STILL SEE SOME TEMPORARY LOWERING OF THE
WET BULB ZERO BELOW 6000 FEET DUE TO STRONGER CONVECTION...BRINGING
ACCUMULATING SNOW TO THE MOUNTAINS...INCLUDING THE HIGHER PEAKS IN
SAN DIEGO COUNTY. NEW RAINFALL AMOUNTS ON WEDNESDAY ARE EXPECTED
TO BE BETWEEN ONE-HALF TO ONE INCH FOR THE COAST AND
VALLEYS...AND BETWEEN ONE TO TWO INCHES FOR THE MOUNTAINS...AND
AROUND ONE-HALF INCH OR LESS FOR THE DESERTS.
SHOWERS WILL LINGER IN THE MOUNTAINS WEDNESDAY NIGHT. RIDGING
ENSUES WITH MILDER AND DRIER WEATHER FOR THURSDAY AND FRIDAY. A
WEAK UPPER LEVEL TROUGH IS STILL INDICATED BY THE MODELS TO PASS
OVERHEAD FRIDAY NIGHT INTO SATURDAY MORNING...WHERE WE HAVE
CONTINUED TO INDICATE JUST A SLIGHT CHANCE OF SHOWERS. AFTER
SATURDAY...A LARGE AREA OF HIGH PRESSURE WILL SETUP ACROSS THE
EASTERN PACIFIC AND SOUTHWEST CALIFORNIA...BRINGING MUCH WARMER
TEMPERATURES AND SUNNY SKIES THROUGH EARLY NEXT WEEK.
&&
.AVIATION...
161000Z...COAST/VALLEYS/MOUNTAINS...CLOUDS WITH BASES VARYING
BETWEEN 3000 FEET MSL AND 8000 FEET MSL AND ISOLATED -SHRA TODAY
THROUGH THE EVENING. BETWEEN 15-20Z MORE PROBABLE SHOWERS AND MORE
WIDESPREAD CIGS 2500-3000 FEET MSL. AFTER 09Z LATE TONIGHT RAIN WITH
A FEW THUNDERSTORMS AND CIGS OF 2000 FEET MSL. HEAVIER RAIN WILL
DROP CIGS BELOW 2000 FEET MSL AND VIS 2-5SM. DESERTS...VARIABLE
CLOUDS AOA 8000 FEET MSL TODAY...LOWERING LATE TONIGHT.
&&
.MARINE...
200 AM...A WEAK COLD FRONT WILL MOVE THROUGH COASTAL WATERS THIS
MORNING WITH BRIEFLY GUSTY SOUTHERLY WINDS. A MUCH STRONGER FRONT
ARRIVES EARLY WEDNESDAY MORNING WITH STRONG SOUTHWEST WINDS TURNING
NORTHWEST BY LATE WEDNESDAY MORNING. IN ADDITION...A LARGE WEST
SWELL WILL PEAK TODAY AND GRADUALLY SUBSIDE TONIGHT AND WEDNESDAY.
SEE THE SMALL CRAFT ADVISORY FOR DETAILS...LAXMWWSGX.
THESE COLD FRONTS WILL ALSO BRING SOME THUNDERSTORMS...MOST LIKELY
WEDNESDAY MORNING. THESE ARE CAPABLE OF PRODUCING WATERSPOUTS AND
STRONG GUSTY WINDS. SEE THE MARINE WEATHER STATEMENT FOR
DETAILS...LAXMWSSGX.
&&
.BEACHES...
200 AM...A LARGE WEST SWELL WILL PEAK TODAY AND BRING HIGH SURF AND
STRONG RIP CURRENTS TO AREA BEACHES. THE SURF WILL SLOWLY SUBSIDE
LATE TODAY THROUGH WEDNESDAY. A HIGH SURF ADVISORY REMAINS IN EFFECT
THROUGH WEDNESDAY MORNING. SEE THE HIGH SURF ADVISORY FOR THE SURF
DETAILS...LAXCFWSGX.
&&
.SKYWARN...
SKYWARN ACTIVATION MAY BE REQUESTED THIS AFTERNOON THROUGH
WEDNESDAY DUE TO POTENTIAL HEAVY RAIN AND ISOLATED THUNDERSTORMS.
WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS TO THE NATIONAL WEATHER SERVICE.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...SMALL CRAFT ADVISORY UNTIL 10 PM PST WEDNESDAY FOR THE BEACHES
IN THE SAN DIEGO COUNTY COASTAL AREAS.
HIGH SURF ADVISORY UNTIL NOON PST WEDNESDAY FOR THE BEACHES IN
THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO COUNTY COASTAL
AREAS.
WINTER WEATHER ADVISORY UNTIL 6 PM PST THIS EVENING ABOVE 6000
FEET FOR THE SAN BERNARDINO COUNTY MOUNTAINS.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH WEDNESDAY AFTERNOON
ABOVE 5500 FEET FOR THE SAN BERNARDINO COUNTY MOUNTAINS.
FLASH FLOOD WATCH FROM NOON PST TODAY THROUGH WEDNESDAY
AFTERNOON FOR THE RIVERSIDE COUNTY MOUNTAINS...SANTA ANA
MOUNTAINS AND FOOTHILLS.
WINTER WEATHER ADVISORY FROM 6 AM TO 8 PM PST WEDNESDAY FOR THE
RIVERSIDE COUNTY MOUNTAINS...SAN DIEGO COUNTY MOUNTAINS.
PZ...SMALL CRAFT ADVISORY UNTIL 10 PM PST WEDNESDAY FOR THE BEACHES
IN THE COASTAL WATERS FROM SAN MATEO POINT TO THE MEXICAN
BORDER AND OUT 30 NM...WATERS FROM SAN MATEO POINT TO THE
MEXICAN BORDER EXTENDING 30 TO 60 NM OUT INCLUDING SAN
CLEMENTE ISLAND.
&&
$$
PUBLIC...BROTHERTON
AVIATION/MARINE...MM
AREA FORECAST DISCUSSION
NWS ALBANY NY
930 PM EST WED DEC 17 2014
.SYNOPSIS...
THE COMBINATION OF LOW PRESSURE STRENGTHENING OFF THE NORTHERN NEW
ENGLAND COAST...AND AN UPPER LEVEL DISTURBANCE PASSING THROUGH
OVERNIGHT...WILL KEEP SKIES MOSTLY CLOUDY ALONG WITH SOME RAIN AND
SNOW SHOWERS. SNOW SHOWERS WILL BE MOST FREQUENT ACROSS THE SOUTHERN
ADIRONDACKS AND SOUTHERN VERMONT. THURSDAY WILL BE BLUSTERY...
ALTHOUGH SOME BREAKS IN THE CLOUDS WILL BE POSSIBLE SOUTH OF THE
CAPITAL REGION. SLIGHTLY COLDER AIR WILL SEEP INTO THE REGION FROM
THE NORTH FOR THURSDAY NIGHT AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 915 PM EST...AS THE SECOND SHORT WAVE TROF MOVES RAPIDLY EAST
ACROSS THE SOUTHEAST GREAT LAKES...RADAR ECHOES HAVE BEEN INCREASING
ON THE KBUF RADAR...AND ACROSS THE WESTERN PART OF THE KBGM RADAR.
EXPECT THIS PCPN TO MAKE IT INTO THE ALBANY FORECAST AREA LATER
TONIGHT...SO THE PREVIOUS FORECAST OF INCREASING THE POPS LATER
TONIGHT HAD A GOOD HANDLE ON THIS. IN FACT...ACROSS SOUTHERN
AREAS...HAVE INCREASED POPS EVEN MORE AND RAISED THEM ABOUT 5 TO 15
PERCENT ABOVE WHAT THE PREVIOUS FORECAST HAD. NO OTHER CHANGES MADE
TO THE PREVIOUS FORECAST.
PREVIOUS DISCUSSION...
WE WILL HAVE TO WATCH RADAR TRENDS CLOSELY OVERNIGHT...AS THE
LATEST RAP13 AND HRRR SUGGEST THAT A MID LEVEL LOW CENTER
ASSOCIATED A COMPACT YET POTENT SHORTWAVE CURRENTLY PASSING OVER
SOUTHERN MICHIGAN POSSIBLY CLOSES OFF SOMEWHERE ACROSS SOUTHERN
AREAS AS IT PASSES QUICKLY EAST/SOUTHEAST. THIS MAY ALLOW FOR SOME
ADDITIONAL MID LEVEL FORCING/DEFORMATION ACROSS CENTRAL AND
NORTHERN PORTIONS OF THE REGION...MAINLY AFTER MIDNIGHT. THIS
ADDITIONAL FORCING COULD ALLOW FOR SOME BURSTS OF SNOW TO
OCCUR...INITIALLY ACROSS HIGHER ELEVATIONS...THEN EVEN ACROSS SOME
VALLEY AREAS...FROM AROUND THE CAPITAL REGION NORTH TO THE LAKE
GEORGE/SARATOGA REGION. THIS COULD ALLOW FOR HIGHER
ACCUMS...PERHAPS INTO THE 2-5 INCH RANGE FOR SOME HIGHER
ELEVATIONS OF THE ADIRONDACKS...SOUTHERN VT...AND WESTERN MA.
ALSO...MANY VALLEY AREAS BETWEEN ALBANY AND LAKE GEORGE COULD
RECEIVE A QUICK COATING...TO JUST UNDER AN INCH OF SNOW LATER
TONIGHT.
OTHERWISE...THE OCCLUDED FRONT HAS PASSED EAST AND NORTH OF THE
REGION. HOWEVER...TWO SHORTWAVES...ONE CURRENTLY LOCATED ACROSS THE
CENTRAL NYS/PA BORDER...AND ANOTHER OVER THE SOUTHERN GREAT
LAKES...WILL CONTINUE TRANSLATING EASTWARD OVERNIGHT. THE FIRST ONE
WILL ALLOW SHOWERS TO PERSIST THROUGH THIS EVENING...ESPECIALLY
ACROSS HIGHER ELEVATIONS OF THE EASTERN CATSKILLS...TACONICS...AND
BERKSHIRES. SOME LIGHT RAIN SHOWERS OR DRIZZLE WILL OCCASIONALLY
REACH THE VALLEY AREAS AS WELL THROUGH EARLY TONIGHT. CLOUD TOPS ARE
RELATIVELY SHALLOW...WITH CLOUD TOP TEMPS GENERALLY IN THE -5 TO -8
C RANGE OR SLIGHTLY WARMER. SO...AT LEAST FOR NOW...THERE APPEARS TO
BE MINIMAL ICE CRYSTALS IN THE CLOUDS...WITH JUST PERHAPS SOME SNOW
GRAINS ACROSS THE HIGHER ELEVATIONS OVER THE NEXT 3 HOURS.
LATER THIS EVENING...THE FIRST IMPULSE WILL PASS EAST OF THE
REGION...WITH THE NEXT ONE POISED UPSTREAM. THE COMBINATION OF
ENHANCED LOW LEVEL MOISTURE FROM THE NEARBY LAKES...AND ADDITIONAL
MID LEVEL MOISTURE ROTATING SOUTHEAST TO SOUTH FROM NORTH OF THE
GREAT LAKES SHOULD ALLOW FOR SOME SEEDER FEEDER PROCESSES...IN
ADDITION TO OVERALL COOLING MID LEVEL TEMPS...TO ALLOW FOR A
TRANSITION TO MAINLY SNOW SHOWERS ACROSS HIGHER TERRAIN...WITH
RAIN SHOWERS OR DRIZZLE GRADUALLY MIXING WITH...AND POSSIBLY
CHANGING TO SNOW OR SNOW GRAINS IN SOME VALLEY AREAS AFTER
MIDNIGHT. AGAIN...OVERALL CLOUD TOP TEMPS MAY NOT BE QUITE COLD
ENOUGH FOR DENDRITIC SNOW CRYSTALS...SO SNOW CONSISTENCY MAY BE
SOMEWHAT GRAINY IN NATURE...AND NOT CONDUCIVE FOR SIGNIFICANT
ACCUMS. AT THIS TIME...IT APPEARS THAT 1-3 INCHES WILL BE POSSIBLE
ACROSS HIGHER ELEVATIONS ACROSS THE SOUTHWEST ADIRONDACKS...AS
WELL AS ACROSS HIGHER...WEST FACING ELEVATIONS ACROSS SOUTHERN VT.
SOME LOCALLY HIGHER AMTS COULD OCCUR FOR ELEVATIONS ABOVE 1800 FT.
ALSO...PORTIONS OF THE BERKSHIRES COULD GET 1-2 INCHES LATE
TONIGHT...WITH PERHAPS SLIGHTLY HIGHER AMTS FOR ELEVATIONS ABOVE
1800 FT IN EASTERN BERKSHIRE CO.
IT APPEARS THAT LOW LEVEL DIRECTIONAL WIND SHEAR WILL PREVENT TRUE
SINGLE BANDED LAKE EFFECT SNOW TO OCCUR...BUT STILL EXPECT A
COMBINATION OF SYNOPTIC...AND OROGRAPHIC EFFECTS TO PRODUCE THE
OVERNIGHT SNOW IN HIGHER ELEVATIONS.
WINDS WILL INCREASE FROM THE WEST TO NORTHWEST OVERNIGHT...WITH
SOME GUSTS POSSIBLY REACHING 25-30 MPH BY DAYBREAK...ESP IN
FAVORABLE CHANNELED W/E VALLEYS...SUCH AS THE MOHAWK RIVER
VALLEY...AS WELL AS IN THE BERKSHIRES.
THE COMBINATION OF CLOUDS...AND INCREASING WIND SHOULD PREVENT
TEMPS FROM FALLING AS LOW AS THE MAV MOS SUGGESTS...AND IN SOME
AREAS...IT IS POSSIBLE THAT TEMPS MAY ONLY DROP TO NEAR OR EVEN
SLIGHTLY ABOVE FREEZING...ESP WITHIN THE IMMEDIATE MOHAWK RIVER
VALLEY/CAPITAL REGION AND UPPER HUDSON RIVER VALLEY. HAVE
THEREFORE WENT WITH...OR ABOVE THE SLIGHTLY WARMER MET MOS FOR
OVERNIGHT MINS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
THURSDAY...AFOREMENTIONED SECOND SHORTWAVE IMPULSE SHOULD MOVE
GENERALLY EAST OF THE REGION IN THE MORNING. HOWEVER...SOME
LINGERING UPSLOPE SNOW SHOWERS WILL LIKELY PERSIST ACROSS PORTIONS
OF THE SW ADIRONDACKS...SOUTHERN VT...AND WESTERN MA. ADDITIONAL
ACCUMS OF AN INCH OR TWO COULD OCCUR WITHIN THE MORE PERSISTENT
AREAS OF SNOW SHOWERS. ELSEWHERE...THE MAIN STORY FOR THU SHOULD
BE GUSTY WINDS...WHICH MAY GUST UP TO 35 MPH OR SLIGHTLY
HIGHER...ESP IN PORTIONS OF THE MOHAWK VALLEY/CAPITAL REGION AND
BERKSHIRES. ALTHOUGH MOST AREAS NEAR AND NORTH OF INTERSTATE 90
SHOULD REMAIN MOSTLY CLOUDY TO OVERCAST...SOME BREAKS OF SUN WILL
BE MORE LIKELY TO THE SOUTH...WITH SKIES POSSIBLY BECOMING MOSTLY
SUNNY AT TIMES ACROSS PORTIONS OF THE MID HUDSON
VALLEY...LITCHFIELD CO CT...AND POSSIBLY EXTREME SE VT. IN THESE
AREAS...TEMPS COULD WARM INTO THE 40S. ELSEWHERE...EXPECT MAINLY
30S IN VALLEYS...AND UPPER 20S/LOWER 30S ACROSS HIGHER ELEVATIONS.
THU NT-FRI NT...A SURFACE TROUGH IS EXPECTED TO GRADUALLY SETTLE
SOUTHWARD LATE THU NT INTO FRI...WITH A SLIGHTLY COLDER...SHALLOW
AIR MASS IN ITS WAKE. AS THE TROUGH PASSES...IT COULD ALLOW FOR A
BRIEF RESURGENCE IN SNOW SHOWERS/FLURRIES...MAINLY ACROSS HIGHER
ELEVATIONS LATE THU NT. AS WINDS SHIFT MORE INTO THE NW TO N IN
THE WAKE OF THE TROUGH...ANY LAKE ENHANCED SNOW SHOWERS SHOULD
SHIFT INTO THE CENTRAL NYS...PERHAPS OCCASIONALLY GRAZING THE
CATSKILLS. ELSEWHERE...THE POTENTIAL FOR CLEARING SKIES WILL
INCREASE IN AT LEAST VALLEY AREAS DURING FRIDAY...WITH MAINLY
CLEAR SKIES ANTICIPATED FOR FRI NT. TEMP THU NT SHOULD FALL INTO
THE 20S IN MOST AREAS...WITH SOME TEENS POSSIBLE ACROSS THE
SOUTHERN ADIRONDACKS. FRI SHOULD BE CHILLY...WITH MAX TEMPS MAINLY
REACHING THE LOWER/MID 30S IN VALLEY AREAS...EXCEPT NEAR 40 ACROSS
THE MID HUDSON VALLEY AND SOUTHERN LITCHFIELD CO CT...WITH MAINLY
20S TO LOWER 30S EXPECTED ACROSS HIGHER ELEVATIONS. FRI NT SHOULD
BE COLDER...WITH MOST MIN TEMPS FALLING INTO THE LOWER/MID 20S IN
VALLEYS...AND TEENS ACROSS HIGHER TERRAIN.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
SATURDAY STILL LOOKS DRY WITH SEASONABLY CHILLY TEMPERATURES. AFTER
THAT...IT LOOKS AS IF WE WILL BE DEALING WITH A MAINLY WEAK SOUTHERN
STREAM DISTURBANCE...BUT THEN A POTENTIALLY MUCH STRONGER "PHASED"
SYSTEM AS HEAD TO CHRISTMAS EVE.
THE ONLY DAY THAT WE MIGHT SEE ANY SOME SUNSHINE WOULD BE
SATURDAY...OTHERWISE PLENTY OF CLOUDS WILL PERSIST. EITHER WAY LOOK
FOR HIGHS FROM THE UPPER 20S NORTHWEST TO LOOK TO MID 30S SOUTH.
BY SUNDAY...WE WILL BE DEALING WITH AN EASTERLY FLOW FROM HIGH
PRESSURE ANCHORED IN EXTREME EASTERN CANADA...AS WELL AS SOME SORT
OF WEAK WAVE DEVELOPING WELL SOUTH IN THE JETSTREAM. ALSO...THERE
MIGHT BE AN EVEN WEAKER WAVE IN THE NORTHERN BRANCH OF THE JETSTREAM
THAT MIGHT INTERACT WITH THE SOUTHERN ONE TO DEVELOP SOME SORT OF
INVERTED TROUGH LATE SUNDAY INTO MONDAY. THIS FEATURE...COMBINED
WITH AN EASTERLY FLOW...COULD TRIGGER ENOUGH LIFT TO PRODUCE WHAT
LOOKS TO BE NUISANCE TYPE PRECIPITATION...MOUNTAIN SNOW AND A VALLEY
RAIN/SNOW MIX SUNDAY INTO MONDAY. AGAIN...THIS IS NOT GOING TO BE A
BIG STORM BUT IT COULD PRODUCE SOME SLIPPERY ROADS...ESPECIALLY
SUNDAY NIGHT AND HIGHER ELEVATIONS. THE TIMING OF THIS POSSIBLE
EVENT IS STILL UNCERTAIN SO FOR NOW WE HAVE INCLUDED SLIGHT CHANCES
SATURDAY NIGHT...AND LOW CHANCES SUNDAY INTO SUNDAY NIGHT AND SLIGHT
CHANCES
MONDAY.
HIGHS SUNDAY WILL GENERALLY BE IN THE 30S...ABOVE FREEZING IN THE
VALLEYS. LOWS SUNDAY NIGHT WILL BE AROUND 30 IN MOST PLACES. HIGHS
MONDAY AGAIN IN THE 30S.
BY LATE MONDAY...THE EUROPEAN AND GFS FORECAST MODELS ARE
FORECASTING A MUCH STRONGER TROUGH ASSOCIATED WITH THE NORTHERN
BRANCH TO DIG IN THE NATION/S MID SECTION. THIS TROUGH IS FORECAST
TO INTERACT WITH SOUTHERN STREAM ENERGY TO PRODUCE WHAT COULD BE A
POWERFUL STORM AS WE HEAD INTO LATE TUESDAY AND WEDNESDAY.
THE TRACK OF THIS STORM LOOKS TO BE ALONG OR NEAR THE APPALACHIAN
MOUNTAINS...WELL TO THE WEST OF THE HUDSON VALLEY. IT WOULD IMPACT
OUR REGION MAINLY ON CHRISTMAS EVE. A STORM WITH THIS TRACK WOULD
LIKELY BRING MOSTLY RAIN...PERHAPS A LITTLE WINTRY MIX ON THE FRONT
SIDE. AS IT MOVES UP TO OUR NORTHWEST...IT WOULD PULL AIR IN COLD
ENOUGH TO PERHAPS SWITCH LEFTOVER RAIN SHOWERS INTO SNOW SHOWERS BY
CHRISTMAS EVE NIGHT.
THIS STORM MIGHT BRING SOME STRONG WIND TO THE HIGHER TERRAIN
WEDNESDAY...AS IT LOOKS SIMILAR TO THE SETUP OF THE GREAT
APPALACHIAN STORM OF 1950 AS WELL AS THE "CLEVELAND BOMB" OF 1978.
HEAVY RAIN MIGHT TRIGGER SOME HYDRO ISSUES AS WE STILL HAVE A BIT OF
SNOW TO MELT IN THE MOUNTAINS.
BEING NEARLY A WEEK AWAY A LOT OF THE SYNOPTIC SETUP COULD
CHANGE...BUT THIS STORM DEFINITELY BEARS WATCHING.
HIGHS ON WEDNESDAY LOOK TO BE MAINLY IN THE 40S...DROPPING TO BELOW
FREEZING BY LATE CHRISTMAS EVE NIGHT.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS A COUPLE OF SHORTWAVE TROFS ROTATE ACROSS THE REGION TONIGHT AND
EARLY THURSDAY...WIDESPREAD CLOUDINESS WILL PERSIST AT THE
KGFL/KALB/KPOU/KPSF TAF SITES. ON THURSDAY...AFTER THE SECOND SHORT
WAVE TROF HAS PASSED THROUGH...CLOUDS WILL SLOWLY DECREASE.
FOR TONIGHT...EXPECT MVFR TO VFR CONDITIONS AT THE KGFL/KALB SITES...
WITH MAINLY VFR CONDITIONS AT KPOU. AT KPSF...UPSLOPE FLOW COMBINED
WITH THE SHORT WAVE TROFS WILL PRODUCE MVFR TO OCCASIONAL IFR
CONDITIONS. ON THURSDAY...EXPECT KGFL/KALB/KPOU TO HAVE A BKN/OVC
VFR CLOUD DECK...WHILE KPSF IS MAINLY MVFR DUE TO THE UPSLOPE FLOW.
SURFACE WINDS WILL BE WESTERLY TONIGHT AT 8 TO 12 KTS WITH SOME
GUSTS UP TO 20 KTS...ESPECIALLY AT KALB/KPSF. ON THURSDAY THE WIND
SPEEDS WILL INCREASE TO 10 TO 15 KTS WITH GUSTS OF 18 TO 25 KTS.
LATE IN THE DAY THE SPEED WILL DIMINISH.
OUTLOOK...
THURSDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.
FRIDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN.
SUNDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN.
SUNDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN.
MONDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...SHSN.
&&
.HYDROLOGY...
NO HYDROLOGIC CONCERNS THROUGH THE REMAINDER OF THE WEEK.
ADDITIONAL LIGHT RAIN OR SNOW SHOWERS WILL CONTINUE INTO TONIGHT.
BASIN AVERAGE PRECIP AMOUNTS WILL BE LIGHT...GENERALLY LESS THAN A
QUARTER OF AN INCH. ONLY VERY MINOR RISES ARE EXPECTED ON RIVERS
AND STREAMS...WITH MOST RIVER FLOWS EXPECTED TO REMAIN FAIRLY
STEADY.
SOME ADDITIONAL LIGHT MOUNTAIN SNOW SHOWERS ARE POSSIBLE THURSDAY
INTO FRIDAY...BUT THESE VERY BE FAIRLY LIMITED AND WON/T HAVE ANY
IMPACT ON AREA WATERWAYS. TEMPERATURES LOOK TO BE A LITTLE COLDER
FOR THURS/FRI...WHICH WILL LIMIT THE AMOUNT OF SNOW MELT THAT
OCCURS. MAINLY DRY WEATHER IS EXPECTED FOR THE WEEKEND...WITH JUST
A LOW CHANCE FOR SOME LIGHT SNOW.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR
WEBSITE. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...GJM/KL
NEAR TERM...GJM/KL
SHORT TERM...KL
LONG TERM...HWJIV
AVIATION...GJM
HYDROLOGY...KL
AREA FORECAST DISCUSSION
NWS ALBANY NY
712 PM EST WED DEC 17 2014
.SYNOPSIS...
THE COMBINATION OF LOW PRESSURE STRENGTHENING OFF THE NORTHERN NEW
ENGLAND COAST...AND AN UPPER LEVEL DISTURBANCE PASSING THROUGH
OVERNIGHT...WILL KEEP SKIES MOSTLY CLOUDY ALONG WITH SOME RAIN AND
SNOW SHOWERS. SNOW SHOWERS WILL BE MOST FREQUENT ACROSS THE SOUTHERN
ADIRONDACKS AND SOUTHERN VERMONT. THURSDAY WILL BE BLUSTERY...
ALTHOUGH SOME BREAKS IN THE CLOUDS WILL BE POSSIBLE SOUTH OF THE
CAPITAL REGION. SLIGHTLY COLDER AIR WILL SEEP INTO THE REGION FROM
THE NORTH FOR THURSDAY NIGHT AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 645 PM EST...RADAR ECHOES ASSOCIATED WITH THE FIRST SHORTWAVE
TROF MOVING THROUGH THE REGION HAVE BEEN WEAKENING DURING THE PAST
HOUR...SO DECIDED TO KEEP POPS MAINLY IN THE CHANCE RANGE FOR THIS
EVENING WITH SOME LIKELY POPS ACROSS SOME HIGHER TERRAIN AREAS.
OTHERWISE HAVE ONLY MADE SOME HOURLY TEMP ADJUSTMENTS TO REFLECT
CURRENT CONDITIONS...AND ALSO INCREASED THE CLOUD COVER FOR TONIGHT.
PREVIOUS DISCUSSION...
WE WILL HAVE TO WATCH RADAR TRENDS CLOSELY OVERNIGHT...AS THE
LATEST RAP13 AND HRRR SUGGEST THAT A MID LEVEL LOW CENTER
ASSOCIATED A COMPACT YET POTENT SHORTWAVE CURRENTLY PASSING OVER
SOUTHERN MICHIGAN POSSIBLY CLOSES OFF SOMEWHERE ACROSS SOUTHERN
AREAS AS IT PASSES QUICKLY EAST/SOUTHEAST. THIS MAY ALLOW FOR SOME
ADDITIONAL MID LEVEL FORCING/DEFORMATION ACROSS CENTRAL AND
NORTHERN PORTIONS OF THE REGION...MAINLY AFTER MIDNIGHT. THIS
ADDITIONAL FORCING COULD ALLOW FOR SOME BURSTS OF SNOW TO
OCCUR...INITIALLY ACROSS HIGHER ELEVATIONS...THEN EVEN ACROSS SOME
VALLEY AREAS...FROM AROUND THE CAPITAL REGION NORTH TO THE LAKE
GEORGE/SARATOGA REGION. THIS COULD ALLOW FOR HIGHER
ACCUMS...PERHAPS INTO THE 2-5 INCH RANGE FOR SOME HIGHER
ELEVATIONS OF THE ADIRONDACKS...SOUTHERN VT...AND WESTERN MA.
ALSO...MANY VALLEY AREAS BETWEEN ALBANY AND LAKE GEORGE COULD
RECEIVE A QUICK COATING...TO JUST UNDER AN INCH OF SNOW LATER
TONIGHT.
OTHERWISE...THE OCCLUDED FRONT HAS PASSED EAST AND NORTH OF THE
REGION. HOWEVER...TWO SHORTWAVES...ONE CURRENTLY LOCATED ACROSS THE
CENTRAL NYS/PA BORDER...AND ANOTHER OVER THE SOUTHERN GREAT
LAKES...WILL CONTINUE TRANSLATING EASTWARD OVERNIGHT. THE FIRST ONE
WILL ALLOW SHOWERS TO PERSIST THROUGH THIS EVENING...ESPECIALLY
ACROSS HIGHER ELEVATIONS OF THE EASTERN CATSKILLS...TACONICS...AND
BERKSHIRES. SOME LIGHT RAIN SHOWERS OR DRIZZLE WILL OCCASIONALLY
REACH THE VALLEY AREAS AS WELL THROUGH EARLY TONIGHT. CLOUD TOPS ARE
RELATIVELY SHALLOW...WITH CLOUD TOP TEMPS GENERALLY IN THE -5 TO -8
C RANGE OR SLIGHTLY WARMER. SO...AT LEAST FOR NOW...THERE APPEARS TO
BE MINIMAL ICE CRYSTALS IN THE CLOUDS...WITH JUST PERHAPS SOME SNOW
GRAINS ACROSS THE HIGHER ELEVATIONS OVER THE NEXT 3 HOURS.
LATER THIS EVENING...THE FIRST IMPULSE WILL PASS EAST OF THE
REGION...WITH THE NEXT ONE POISED UPSTREAM. THE COMBINATION OF
ENHANCED LOW LEVEL MOISTURE FROM THE NEARBY LAKES...AND ADDITIONAL
MID LEVEL MOISTURE ROTATING SOUTHEAST TO SOUTH FROM NORTH OF THE
GREAT LAKES SHOULD ALLOW FOR SOME SEEDER FEEDER PROCESSES...IN
ADDITION TO OVERALL COOLING MID LEVEL TEMPS...TO ALLOW FOR A
TRANSITION TO MAINLY SNOW SHOWERS ACROSS HIGHER TERRAIN...WITH
RAIN SHOWERS OR DRIZZLE GRADUALLY MIXING WITH...AND POSSIBLY
CHANGING TO SNOW OR SNOW GRAINS IN SOME VALLEY AREAS AFTER
MIDNIGHT. AGAIN...OVERALL CLOUD TOP TEMPS MAY NOT BE QUITE COLD
ENOUGH FOR DENDRITIC SNOW CRYSTALS...SO SNOW CONSISTENCY MAY BE
SOMEWHAT GRAINY IN NATURE...AND NOT CONDUCIVE FOR SIGNIFICANT
ACCUMS. AT THIS TIME...IT APPEARS THAT 1-3 INCHES WILL BE POSSIBLE
ACROSS HIGHER ELEVATIONS ACROSS THE SOUTHWEST ADIRONDACKS...AS
WELL AS ACROSS HIGHER...WEST FACING ELEVATIONS ACROSS SOUTHERN VT.
SOME LOCALLY HIGHER AMTS COULD OCCUR FOR ELEVATIONS ABOVE 1800 FT.
ALSO...PORTIONS OF THE BERKSHIRES COULD GET 1-2 INCHES LATE
TONIGHT...WITH PERHAPS SLIGHTLY HIGHER AMTS FOR ELEVATIONS ABOVE
1800 FT IN EASTERN BERKSHIRE CO.
IT APPEARS THAT LOW LEVEL DIRECTIONAL WIND SHEAR WILL PREVENT TRUE
SINGLE BANDED LAKE EFFECT SNOW TO OCCUR...BUT STILL EXPECT A
COMBINATION OF SYNOPTIC...AND OROGRAPHIC EFFECTS TO PRODUCE THE
OVERNIGHT SNOW IN HIGHER ELEVATIONS.
WINDS WILL INCREASE FROM THE WEST TO NORTHWEST OVERNIGHT...WITH
SOME GUSTS POSSIBLY REACHING 25-30 MPH BY DAYBREAK...ESP IN
FAVORABLE CHANNELED W/E VALLEYS...SUCH AS THE MOHAWK RIVER
VALLEY...AS WELL AS IN THE BERKSHIRES.
THE COMBINATION OF CLOUDS...AND INCREASING WIND SHOULD PREVENT
TEMPS FROM FALLING AS LOW AS THE MAV MOS SUGGESTS...AND IN SOME
AREAS...IT IS POSSIBLE THAT TEMPS MAY ONLY DROP TO NEAR OR EVEN
SLIGHTLY ABOVE FREEZING...ESP WITHIN THE IMMEDIATE MOHAWK RIVER
VALLEY/CAPITAL REGION AND UPPER HUDSON RIVER VALLEY. HAVE
THEREFORE WENT WITH...OR ABOVE THE SLIGHTLY WARMER MET MOS FOR
OVERNIGHT MINS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
THURSDAY...AFOREMENTIONED SECOND SHORTWAVE IMPULSE SHOULD MOVE
GENERALLY EAST OF THE REGION IN THE MORNING. HOWEVER...SOME
LINGERING UPSLOPE SNOW SHOWERS WILL LIKELY PERSIST ACROSS PORTIONS
OF THE SW ADIRONDACKS...SOUTHERN VT...AND WESTERN MA. ADDITIONAL
ACCUMS OF AN INCH OR TWO COULD OCCUR WITHIN THE MORE PERSISTENT
AREAS OF SNOW SHOWERS. ELSEWHERE...THE MAIN STORY FOR THU SHOULD
BE GUSTY WINDS...WHICH MAY GUST UP TO 35 MPH OR SLIGHTLY
HIGHER...ESP IN PORTIONS OF THE MOHAWK VALLEY/CAPITAL REGION AND
BERKSHIRES. ALTHOUGH MOST AREAS NEAR AND NORTH OF INTERSTATE 90
SHOULD REMAIN MOSTLY CLOUDY TO OVERCAST...SOME BREAKS OF SUN WILL
BE MORE LIKELY TO THE SOUTH...WITH SKIES POSSIBLY BECOMING MOSTLY
SUNNY AT TIMES ACROSS PORTIONS OF THE MID HUDSON
VALLEY...LITCHFIELD CO CT...AND POSSIBLY EXTREME SE VT. IN THESE
AREAS...TEMPS COULD WARM INTO THE 40S. ELSEWHERE...EXPECT MAINLY
30S IN VALLEYS...AND UPPER 20S/LOWER 30S ACROSS HIGHER ELEVATIONS.
THU NT-FRI NT...A SURFACE TROUGH IS EXPECTED TO GRADUALLY SETTLE
SOUTHWARD LATE THU NT INTO FRI...WITH A SLIGHTLY COLDER...SHALLOW
AIR MASS IN ITS WAKE. AS THE TROUGH PASSES...IT COULD ALLOW FOR A
BRIEF RESURGENCE IN SNOW SHOWERS/FLURRIES...MAINLY ACROSS HIGHER
ELEVATIONS LATE THU NT. AS WINDS SHIFT MORE INTO THE NW TO N IN
THE WAKE OF THE TROUGH...ANY LAKE ENHANCED SNOW SHOWERS SHOULD
SHIFT INTO THE CENTRAL NYS...PERHAPS OCCASIONALLY GRAZING THE
CATSKILLS. ELSEWHERE...THE POTENTIAL FOR CLEARING SKIES WILL
INCREASE IN AT LEAST VALLEY AREAS DURING FRIDAY...WITH MAINLY
CLEAR SKIES ANTICIPATED FOR FRI NT. TEMP THU NT SHOULD FALL INTO
THE 20S IN MOST AREAS...WITH SOME TEENS POSSIBLE ACROSS THE
SOUTHERN ADIRONDACKS. FRI SHOULD BE CHILLY...WITH MAX TEMPS MAINLY
REACHING THE LOWER/MID 30S IN VALLEY AREAS...EXCEPT NEAR 40 ACROSS
THE MID HUDSON VALLEY AND SOUTHERN LITCHFIELD CO CT...WITH MAINLY
20S TO LOWER 30S EXPECTED ACROSS HIGHER ELEVATIONS. FRI NT SHOULD
BE COLDER...WITH MOST MIN TEMPS FALLING INTO THE LOWER/MID 20S IN
VALLEYS...AND TEENS ACROSS HIGHER TERRAIN.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
SATURDAY STILL LOOKS DRY WITH SEASONABLY CHILLY TEMPERATURES. AFTER
THAT...IT LOOKS AS IF WE WILL BE DEALING WITH A MAINLY WEAK SOUTHERN
STREAM DISTURBANCE...BUT THEN A POTENTIALLY MUCH STRONGER "PHASED"
SYSTEM AS HEAD TO CHRISTMAS EVE.
THE ONLY DAY THAT WE MIGHT SEE ANY SOME SUNSHINE WOULD BE
SATURDAY...OTHERWISE PLENTY OF CLOUDS WILL PERSIST. EITHER WAY LOOK
FOR HIGHS FROM THE UPPER 20S NORTHWEST TO LOOK TO MID 30S SOUTH.
BY SUNDAY...WE WILL BE DEALING WITH AN EASTERLY FLOW FROM HIGH
PRESSURE ANCHORED IN EXTREME EASTERN CANADA...AS WELL AS SOME SORT
OF WEAK WAVE DEVELOPING WELL SOUTH IN THE JETSTREAM. ALSO...THERE
MIGHT BE AN EVEN WEAKER WAVE IN THE NORTHERN BRANCH OF THE JETSTREAM
THAT MIGHT INTERACT WITH THE SOUTHERN ONE TO DEVELOP SOME SORT OF
INVERTED TROUGH LATE SUNDAY INTO MONDAY. THIS FEATURE...COMBINED
WITH AN EASTERLY FLOW...COULD TRIGGER ENOUGH LIFT TO PRODUCE WHAT
LOOKS TO BE NUISANCE TYPE PRECIPITATION...MOUNTAIN SNOW AND A VALLEY
RAIN/SNOW MIX SUNDAY INTO MONDAY. AGAIN...THIS IS NOT GOING TO BE A
BIG STORM BUT IT COULD PRODUCE SOME SLIPPERY ROADS...ESPECIALLY
SUNDAY NIGHT AND HIGHER ELEVATIONS. THE TIMING OF THIS POSSIBLE
EVENT IS STILL UNCERTAIN SO FOR NOW WE HAVE INCLUDED SLIGHT CHANCES
SATURDAY NIGHT...AND LOW CHANCES SUNDAY INTO SUNDAY NIGHT AND SLIGHT
CHANCES
MONDAY.
HIGHS SUNDAY WILL GENERALLY BE IN THE 30S...ABOVE FREEZING IN THE
VALLEYS. LOWS SUNDAY NIGHT WILL BE AROUND 30 IN MOST PLACES. HIGHS
MONDAY AGAIN IN THE 30S.
BY LATE MONDAY...THE EUROPEAN AND GFS FORECAST MODELS ARE
FORECASTING A MUCH STRONGER TROUGH ASSOCIATED WITH THE NORTHERN
BRANCH TO DIG IN THE NATION/S MID SECTION. THIS TROUGH IS FORECAST
TO INTERACT WITH SOUTHERN STREAM ENERGY TO PRODUCE WHAT COULD BE A
POWERFUL STORM AS WE HEAD INTO LATE TUESDAY AND WEDNESDAY.
THE TRACK OF THIS STORM LOOKS TO BE ALONG OR NEAR THE APPALACHIAN
MOUNTAINS...WELL TO THE WEST OF THE HUDSON VALLEY. IT WOULD IMPACT
OUR REGION MAINLY ON CHRISTMAS EVE. A STORM WITH THIS TRACK WOULD
LIKELY BRING MOSTLY RAIN...PERHAPS A LITTLE WINTRY MIX ON THE FRONT
SIDE. AS IT MOVES UP TO OUR NORTHWEST...IT WOULD PULL AIR IN COLD
ENOUGH TO PERHAPS SWITCH LEFTOVER RAIN SHOWERS INTO SNOW SHOWERS BY
CHRISTMAS EVE NIGHT.
THIS STORM MIGHT BRING SOME STRONG WIND TO THE HIGHER TERRAIN
WEDNESDAY...AS IT LOOKS SIMILAR TO THE SETUP OF THE GREAT
APPALACHIAN STORM OF 1950 AS WELL AS THE "CLEVELAND BOMB" OF 1978.
HEAVY RAIN MIGHT TRIGGER SOME HYDRO ISSUES AS WE STILL HAVE A BIT OF
SNOW TO MELT IN THE MOUNTAINS.
BEING NEARLY A WEEK AWAY A LOT OF THE SYNOPTIC SETUP COULD
CHANGE...BUT THIS STORM DEFINITELY BEARS WATCHING.
HIGHS ON WEDNESDAY LOOK TO BE MAINLY IN THE 40S...DROPPING TO BELOW
FREEZING BY LATE CHRISTMAS EVE NIGHT.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS A COUPLE OF SHORTWAVE TROFS ROTATE ACROSS THE REGION TONIGHT AND
EARLY THURSDAY...WIDESPREAD CLOUDINESS WILL PERSIST AT THE
KGFL/KALB/KPOU/KPSF TAF SITES. ON THURSDAY...AFTER THE SECOND SHORT
WAVE TROF HAS PASSED THROUGH...CLOUDS WILL SLOWLY DECREASE.
FOR TONIGHT...EXPECT MVFR TO VFR CONDITIONS AT THE KGFL/KALB SITES...
WITH MAINLY VFR CONDITIONS AT KPOU. AT KPSF...UPSLOPE FLOW COMBINED
WITH THE SHORT WAVE TROFS WILL PRODUCE MVFR TO OCCASIONAL IFR
CONDITIONS. ON THURSDAY...EXPECT KGFL/KALB/KPOU TO HAVE A BKN/OVC
VFR CLOUD DECK...WHILE KPSF IS MAINLY MVFR DUE TO THE UPSLOPE FLOW.
SURFACE WINDS WILL BE WESTERLY TONIGHT AT 8 TO 12 KTS WITH SOME
GUSTS UP TO 20 KTS...ESPECIALLY AT KALB/KPSF. ON THURSDAY THE WIND
SPEEDS WILL INCREASE TO 10 TO 15 KTS WITH GUSTS OF 18 TO 25 KTS.
LATE IN THE DAY THE SPEED WILL DIMINISH.
OUTLOOK...
THURSDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.
FRIDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN.
SUNDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN.
SUNDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN.
MONDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...SHSN.
&&
.HYDROLOGY...
NO HYDROLOGIC CONCERNS THROUGH THE REMAINDER OF THE WEEK.
ADDITIONAL LIGHT RAIN OR SNOW SHOWERS WILL CONTINUE INTO TONIGHT.
BASIN AVERAGE PRECIP AMOUNTS WILL BE LIGHT...GENERALLY LESS THAN A
QUARTER OF AN INCH. ONLY VERY MINOR RISES ARE EXPECTED ON RIVERS
AND STREAMS...WITH MOST RIVER FLOWS EXPECTED TO REMAIN FAIRLY
STEADY.
SOME ADDITIONAL LIGHT MOUNTAIN SNOW SHOWERS ARE POSSIBLE THURSDAY
INTO FRIDAY...BUT THESE VERY BE FAIRLY LIMITED AND WON/T HAVE ANY
IMPACT ON AREA WATERWAYS. TEMPERATURES LOOK TO BE A LITTLE COLDER
FOR THURS/FRI...WHICH WILL LIMIT THE AMOUNT OF SNOW MELT THAT
OCCURS. MAINLY DRY WEATHER IS EXPECTED FOR THE WEEKEND...WITH JUST
A LOW CHANCE FOR SOME LIGHT SNOW.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR
WEBSITE. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...GJM/KL
NEAR TERM...GJM/KL
SHORT TERM...KL
LONG TERM...HWJIV
AVIATION...GJM
HYDROLOGY...KL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
631 AM EST TUE DEC 16 2014
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL RESULT IN A PERIOD OF RAIN SHOWERS
WORKING ACROSS THE REGION FROM WEST TO EAST TONIGHT. THE SHOWERS
SHOULD COME TO AN END SOMETIME WEDNESDAY MORNING...BUT A FEW HIT AND
MISS RAIN/SNOW SHOWERS WILL LINGER LATER WEDNESDAY INTO THURSDAY
MORNING. A STRENGTHENING LOW PRESSURE CENTER IS EXPECTED TO PASS
SOUTHEAST OF NEW ENGLAND LATE IN THE WEEKEND. IT IS UNCERTAIN AT
THIS TIME IF THIS SYSTEM WILL PASS CLOSE ENOUGH TO PRODUCE
PRECIPITATION ACROSS SOUTHERN NEW ENGLAND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
630 AM UPDATE...
OVERALL TREND IN THE FORECAST REMAINS ON TRACK FOR THIS MORNING.
POTENTIAL FOR FREEZING DRIZZLE SEEMS LOW AT THE MOMENT GIVING THE
HIGH CLOUDS DECK. HAVE NOTICED THAT ORE HAS DROPPED DOWN TO 900 FT
SO PERHAPS SOME PATCHY FREEZING DRIZZLE IN THE NW PORTIONS OF
MASS. RAP BUFKIT SOUNDINGS TO SHOW LOW LEVEL MOISTURE INCREASING
OVER THE NEXT HOUR OR TWO SO SOMETHING TO WATCH STILL. OTHERWISE
MADE A FEW MINOR EDITS ON TIMING OF PRECIP AND DRIZZLE PER LATEST
GUIDANCE.
PREVIOUS DISCUSSION...
THE MAIN CONCERN EARLY THIS MORNING WILL BE FOR PATCHY BLACK ICE
WITH LOW TEMP/DEWPOINT SPREADS. DOES NOT LOOK LIKE IT WILL BE
WIDESPREAD AT THIS TIME...GIVEN CLOUD DECK WORKING IN FROM THE WEST
AND LACK OF FOG. WILL CONTINUE TO MONITOR CLOSELY.
AS FOR THIS AFTERNOON...POTENTIAL FOR SPOTTY DRIZZLE INCREASES WITH
DEEPER LOW LEVEL MOISTURE WORKING INTO THE REGION. THIS WILL FIRST
OCCUR CLOSEST TO THE COAST AND SPREAD INLAND. NOT SURE HOW QUICKLY
THIS WILL HAPPEN THOUGH AND MUCH OF THE DAY WILL PROBABLY END UP DRY
IN MOST LOCALES...WITH JUST A LOT OF CLOUDS. OTHER THAN SPOTTY
DRIZZLE...UPPER LEVEL RIDGING AND DRY MID LEVEL AIR SHOULD KEEP THE
STEADY RAINFALL TO OUR WEST THROUGH LATE AFTERNOON. TEMPS WILL
LIKELY BE ABOVE FREEZING BY THE TIME ANY DRIZZLE ARRIVES.
HIGH TEMPS SHOULD RANGE FROM THE UPPER 30S ACROSS THE INTERIOR HIGH
TERRAIN...TO MAINLY WELL INTO THE 40S ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
TONIGHT...
INITIAL LOW PRESSURE WILL BE LIFTING ACROSS THE GREAT LAKES AS
SECONDARY LOW DEVELOPS NEAR THE MID ATLANTIC COAST AND MOVES
NORTHEAST. THE RESULT WILL BE AN AREA OF RAIN SHOWERS THAT WILL
WORK INTO THE INTERIOR DURING THE EVENING...BUT LIKELY NOT REACH THE
COASTAL PLAIN UNTIL AFTER MIDNIGHT WHEN BETTER FORCING ARRIVES.
UNTIL THAT HAPPENS THOUGH...LOW CLOUDS/PATCHY FOG AND AREAS OF
DRIZZLE WILL BE POSSIBLE. AS FOR PTYPE TONIGHT...THERMAL PROFILES
WILL BE WARM ENOUGH FOR RAIN ACROSS THE ENTIRE REGION. LOW RISK FOR
A BRIEF PERIOD OF SPOTTY FREEZING RAIN ACROSS FAR NORTHWEST MA
BUT NOT TOO EXCITED ABOUT THAT OCCURRING.
THERE IS A EVEN A LOW RISK FOR AN ISOLATED THUNDERSTORM OR TWO
TOWARD DAYBREAK AS SHOWALTER VALUES APPROACH ZERO ACROSS EASTERN NEW
ENGLAND. NOT ENOUGH CONFIDENCE TO INSERT INTO THE FORECAST AT THIS
TIME...BUT SOMETHING LATER SHIFTS WILL HAVE TO KEEP AN EYE ONE.
WEDNESDAY...
SECONDARY LOW PRESSURE WILL LIKELY MOVE ACROSS SOUTHEAST NEW ENGLAND
WED MORNING. RAIN SHOWERS WILL LIKELY LINGER ACROSS OUR EASTERN AND
PARTICULARLY NORTHEAST ZONES INTO PART OF WED MORNING.
OTHERWISE...MAY SEE A FEW SHOWERS WITH THE UPPER LEVEL SHORTWAVE WED
AFTERNOON...BUT THE STEADY PRECIPITATION WILL HAVE ENDED. HIGH
TEMPS WILL BE WELL UP INTO THE 40S...TO PERHAPS EVEN SOME LOWER 50S
ON THE COASTAL PLAIN. A FEW PEEKS OF SUNSHINE WILL ALSO BE POSSIBLE
ACROSS THE COASTAL PLAIN BY AFTERNOON...BUT STILL EXPECT PLENTY OF
CLOUDS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
HIGHLIGHTS...
* SNOW SHOWERS ACROSS THE INTERIOR WED NIGHT INTO THURS
* DRY WEATHER AND AT OR BELOW AVG TEMPS FRIDAY INTO SAT
* POSSIBLE COASTAL SYSTEM SUNDAY INTO MONDAY
OVERVIEW...
OVERALL 12Z GUIDANCE IS IN AGREEMENT SYNOPTICALLY...HOWEVER THERE
ARE MANY ISSUES REGARDING THE SPLIT FLOW ESP FOR THE WEEKEND. IT
DOES LOOK LIKE A PATTERN CHANGE IS GOING TO OCCUR AS UPPER LEVEL
RIDGING BUILDS INTO CALIFORNIA AND HIGH PRESSURE IN CENTRAL CANADA
MOVES TO EASTERN CANADA. THIS SHOULD FAVOR TROUGHING IN THE SW CONUS
MOVING EASTWARD WHICH COULD KEEP OUR PATTERN ACTIVE BEGINNING NEXT
WEEKEND. GUIDANCE TENDS TO HAVE ISSUES WITH THE PATTERN SHIFT AS
WELL AS PHASING SO TIMING ON ANY SYSTEMS MAY SLOW DOWN OR EVEN SPEED
UP. WHILE WE ARE IN TRANSITION...DEPARTING UPPER LEVEL LOW WILL PUSH
TOWARDS THE MARITIMES BY LATE THURSDAY WITH RIDGING TO MOVING IN
FRIDAY INTO SATURDAY. DIGGING SHORTWAVE INTO THE SE CONUS WILL
DEVELOP A LOW PRESSURE SYSTEM IN THE MID-ATLANTIC. THIS SYSTEM MAY
MOVE ACROSS THE BENCHMARK...THE CANAL OR WELL EAST OF THE BENCHMARK.
FOR NOW TRENDED TOWARDS THE ENSEMBLES FOR THIS FORECAST BECAUSE OF
THE AMOUNT OF UNCERTAINTY.
DETAILS...
WEDNESDAY NIGHT INTO THURSDAY...HIGH CONFIDENCE.
UPPER LEVEL LOW WILL SET UP OVER NEW ENGLAND WEDNESDAY NIGHT BEFORE
EXITING OFF INTO THE MARITIMES LATE THURSDAY. A SECONDARY SHORTWAVE
WILL MOVE THROUGH THE FLOW AND OVER THE REGION ALLOWING FOR PRECIP
TO DEVELOP AND CONTINUE INTO THURSDAY MORNING. STRONG CAA WILL MOVE
IN BEHIND THE FIRST SHORTWAVE SO ANTICIPATE PRECIP TO BE MORE IN THE
FORM OF SNOW...ESP AWAY FROM THE COASTLINE. THESE SNOW SHOWERS WILL
BE MORE SCATTERED IN NATURE WED NIGHT THEN BEGIN TO BECOME MORE
ISOLATED BY THURSDAY AS SHORTWAVE MOVES THROUGH AND DRY AIR PUSHES
INTO THE AREA. AM NOT EXPECTING MUCH IN THE WAY OF ACCUMULATIONS BUT
COULD SEE AN QUICK INCH ACROSS THE HIGHER ELEVATIONS INTO THE NW
ZONES.
TEMPERATURES THROUGH THIS PERIOD WILL BE AT OR BELOW AVERAGE AS
STRONG CAA MOVES THROUGH WITHIN THE NORTHWEST FLOW.
FRIDAY INTO SATURDAY...HIGH CONFIDENCE.
AS UPPER LEVEL LOW SPINS INTO THE MARITIMES...HIGH PRESSURE WILL
BUILD INTO SOUTHERN NEW ENGLAND. THIS SILL ALLOW FOR QUIET AND DRY
WEATHER. TEMPERATURES WILL HOVER NEAR AVERAGE DURING THIS TIME
PERIOD.
SUNDAY INTO MONDAY...LOW CONFIDENCE.
MAIN FOCUS OF THE FORECAST WAS ON THIS TRICKY TIME PERIOD. THE
MODELS/ENSEMBLES HAVE OFFERED A VARIETY OF SOLUTIONS OVER THE PAST
FEW DAYS FROM A VERY LOW AMPLITUDE AND FLAT WAVE MOVING THROUGH THE
SOUTHEAST TO A WRAPPED UP SFC LOW HUGGING THE COAST INTO NEW
ENGLAND. THE ECMWF ENSEMBLE MEAN HAS OFFERED THE BEST CONSISTENCY
WHILE THE DETERMINISTIC ECMWF HAS BEEN LESS STABLE IN ITS DETAILS.
THE GFS IS SHOWING A SYSTEM...BUT IT MORE OF A WAVE FOCUSING ON THE
NORTHERN STREAM. THE GEFS SPREAD IS QUITE LARGE...BUT THERE ARE A
FEW MEMBERS AGREEING WITH THE ECMWF ENSEMBLES. BECAUSE OF THE
AMOUNT OF SPREAD...HAVE A VERY LOW CONFIDENCE ON THE FORECAST BUT
TRENDED TOWARDS WPC AN A BLEND OF THE ENSEMBLES.
OVERALL APPEARS THAT PRECIP WILL MOVE INTO THE REGION AND IMPACT
SOUTHERN NEW ENGLAND BETWEEN THE SAT NIGHT INTO MONDAY TIME FRAME.
THERE MAY BE ENOUGH LINGERING COLD AIR FROM DEPARTING HIGH PRESSURE
THAT THERE COULD BE SOME SNOW ACROSS THE INTERIOR. HOWEVER IF THE
STORMS IS WELL EAST OF THE BENCHMARK THEN NO SNOW WILL OCCUR ACROSS
THE INTERIOR AND IT MAY BE ACROSS THE COAST. SO APPEARS THAT THERE
WILL BE P-TYPE ISSUES AND PERHAPS SOME WIND ISSUES IF THE STORM
TRACKS WEST OF THE BENCHMARK. TIDES FOR THE MASS EAST COAST WILL BE
ASTRONOMICALLY HIGH WITH 11.0 SUNDAY MORNING AND 11.4 MONDAY MORNING
AT BOS. IF NE FLOW STRENGTHENS THEN ANTICIPATE A BUILD UP IN SEAS AS
WELL AS SURGE. SO THERE COULD BE COASTAL FLOODING CONCERNS WITH THE
SYSTEM. AS MENTIONED BEFORE...THIS IS A LOW CONFIDENCE FORECAST WITH
MUCH SPREAD ACROSS THE GUIDANCE. HOWEVER THIS STORM WILL NEED TO BE
WATCH OVER THE COMING DAYS.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /TODAY THROUGH WEDNESDAY/...
TODAY...MODERATE CONFIDENCE. MVFR CONDITIONS...MAINLY IN LOW CLOUDS
WILL CONTINUE TO OVER SPREAD THE REGION FROM EAST TO WEST THIS
MORNING. MVFR CONDITIONS WILL PERSIST THROUGH THE AFTERNOON AND
MAY EVEN SEE LOCALIZED IFR CONDITIONS. CHANCES FOR DRIZZLE AND
PATCHY FOG MAY INCREASE IN COVERAGE THIS AFTERNOON AS LOW LEVEL
MOISTURE CONTINUES TO INCREASE.
TONIGHT...MODERATE CONFIDENCE. WIDESPREAD LOW END MVFR TO IFR
CONDITIONS EXPECTED IN LOW CLOUDS AND FOG PATCHES. BAND OF SHOWERS
WILL WORK ACROSS THE REGION FROM WEST TO EAST AS THE NIGHT WEARS ON.
WEDNESDAY...MODERATE CONFIDENCE. MVFR-IFR CONDITIONS FOR THE FIRST
PART OF THE DAY...BUT SHOULD SOME IMPROVEMENT DURING THE AFTERNOON
FROM SOUTH TO NORTH. SHOWERS ALONG THE COASTAL PLAIN EARLY IN THE
MORNING SHOULD DIMINISH TO A FEW HIT AND MISS SHOWERS BY WED
AFTERNOON.
KBOS TERMINAL...MODERATE CONFIDENCE. MAINLY MVFR CONDITIONS TODAY
BUT CAN/T RULE OUT IFR CONDITIONS DEVELOPING...ESPECIALLY DURING THE
AFTERNOON.
KBDL TERMINAL...MODERATE CONFIDENCE. MVFR CONDITIONS SHOULD DEVELOP
BY 12Z AND PERSIST THROUGH THE DAY. CAN/T RULE OUT SOME IFR
CONDITIONS THIS AFTERNOON.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
WEDNESDAY NIGHT THROUGH THURSDAY...HIGH CONFIDENCE. MVFR CIGS IN
SCATTERED SNOW SHOWERS. NORTHWEST WINDS NEAR 25 KTS.
THURSDAY THROUGH SATURDAY...HIGH CONFIDENCE. VFR CONDITIONS EXPECTED.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /TODAY THROUGH WEDNESDAY/...HIGH CONFIDENCE.
TODAY...WEAK RIDGE OF HIGH WILL KEEP WINDS/SEAS WELL BELOW SMALL
CRAFT ADVISORY THRESHOLDS.
TONIGHT AND WEDNESDAY...LOW PRESSURE WILL MOVE ACROSS THE REGION
VERY LATE TONIGHT INTO WEDNESDAY MORNING. SEAS MAY REACH MARGINAL
SMALL CRAFT ADVISORY THRESHOLDS TOWARD DAYBREAK ACROSS OUR EASTERN
OUTER-WATERS. HOWEVER...MAIN SMALL CRAFT CONDITIONS WILL ARRIVE WED
AND ESPECIALLY WED AFTERNOON BEHIND LOW PRESSURE. WESTERLY WIND
GUSTS OF 20 TO 30 KNOTS ARE EXPECTED TO DEVELOP AND SCA HEADLINES
ARE POSTED FOR MOST OPEN WATERS.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...MODERATE TO HIGH CONFIDENCE.
ANTICIPATE SMALL CRAFT ADVISORY WINDS IN NW FLOW BEHIND THE
DEPARTING SYSTEM WED INTO THU. SEAS WILL LIKELY BE NEAR OR ABOVE 5
FEET ACROSS THE OPEN WATERS WED INTO THU. LOW CONFIDENCE OF GALES
WED NIGHT THANKS TO STRONG CAA OVER THE RELATIVELY WARM WATER. WINDS
DIMINISHING AND SEAS SUBSIDING THU NIGHT AND LIKELY BELOW SMALL
CRAFT ADVISORY LEVELS FRI THROUGH SAT.
ALTHOUGH JUST BEYOND THE OUTLOOK PERIOD...WE CONTINUE TO MONITOR A
POTENTIAL COASTAL STORM FOR LATE SATURDAY NIGHT AND SUNDAY. THERE IS
A LARGE UNCERTAINTY IN THE TRACK AND INTENSITY OF THIS SYSTEM AND
ANY CORRESPONDING IMPACT ON WINDS AND SEAS IN THE COASTAL WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM WEDNESDAY TO 7 AM EST THURSDAY
FOR ANZ231>235-237.
SMALL CRAFT ADVISORY FROM 4 AM WEDNESDAY TO 7 AM EST THURSDAY
FOR ANZ250-254>256.
&&
$$
SYNOPSIS...FRANK/DUNTEN
NEAR TERM...FRANK/DUNTEN
SHORT TERM...FRANK
LONG TERM...DUNTEN
AVIATION...FRANK/DUNTEN
MARINE...FRANK/DUNTEN
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
925 PM EST WED DEC 17 2014
.SYNOPSIS...
LOW PRESSURE WILL DEPART TO OUR NORTHEAST THROUGH THURSDAY. HIGH
PRESSURE THEN WILL MOVE TO OUR NORTH ON FRIDAY. WEAK LOW
PRESSURE WILL DEVELOP IN THE GULF OF MEXICO ON SATURDAY THAT WILL
MOVE NORTHEAST ON SUNDAY TO VIRGINA BEACH. A SECOND LOW PRESSURE
SYSTEM WILL THEN FORM AND HEAD UP THE EAST COAST MONDAY INTO
TUESDAY. ANOTHER COLD FRONTAL BOUNDARY WITH ASSOCIATED LOW PRESSURE
SYSTEMS MOVES FROM THE OHIO VALLEY TUESDAY NIGHT INTO OUR REGION ON
WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WE DIDNT MAKE TOO MANY CHANGES TO THE OVERNIGHT AS THE FORECAST
REMAINS CLOSE LATEST HRRR AND RAP CONTINUE TO BYPASS MEASURABLE IN
OUR CWA. SO WE JUST KEPT A CHANCE OF SPRINKLES OR FLURRIES FOR THE
OVERNIGHT FAR NORTH NEAR THE PATH OF THE STRONGEST DPVA. NOT MUCH
MOISTURE AT ALL ABOVE 850MB SEEMS TO BE THE LIMITING FACTOR.
TEMPERATURES WERE FALLING EVER SO SLIGHTLY SLOWER, SO ONLY SLIGHT
UPWARD TWEAKS WERE MADE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
THURSDAY...WE ARE IN SERVICE BACKUP AND STERLING WILL BE WRITING
THE FORECASTS STARTING AT ABOUT 8 AM.
IT WILL BE A BIT COOLER (STILL ABOVE NORMAL)...ABOUT 8-9F PER MODELED
925MB ABOUT 5C COOLER...WITH GUSTY NW WINDS TO 25 MPH.
CONSIDERABLE CLOUDINESS POCONOS WITH MAYBE A FEW FLURRIES? OTHERWISE
A MOSTLY SUNNY START IS EXPECTED BECOMING PARTLY SUNNY OR MOSTLY
CLOUDY FOR A TIME MIDDAY THEN CLEARING LATE IN THE DAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
THURSDAY NIGHT THROUGH SATURDAY: LOW PRESSURE WITH AN ASSOCIATED
COLD FRONT WILL BE LOCATED WELL OFFSHORE OVER ATLANTIC CANADA ON THURSDAY.
THIS WILL ALLOW FOR CONTINUED NORTH TO NORTHWEST FLOW INTO THE
REGION THROUGH FRIDAY. BY SATURDAY WE AWAIT THE APPROACH OF A LOW
PRESSURE SYSTEM FROM THE SOUTH WITH INCREASING CLOUDS AND A MORE
NORTHEASTERLY FLOW. THIS LOW PRESSURE HAS TRENDED WEAKER AND
WEAKER WITH EACH SET OF MODEL RUNS. MANY OF THE 12Z MODELS ONLY
BRING VERY LIGHT QPF IF THAT AND ARE FASTER. WILL KEEP POPS IN THE
CHANCE CATEGORY HIGHEST ACROSS THE SOUTH. FORECAST TEMPERATURES
REFLECT CLOSER TO THE ECMWF AND THE ECMWF MOS IN THESE PERIODS,
DID EDGE COOLER FRIDAY NIGHT WITH CLEAR SKIES.
SATURDAY NIGHT AND SUNDAY: THE MUCH ANTICIPATED LOW PRESSURE SYSTEM
WILL PASS TO OUR SOUTHEAST SATURDAY NIGHT INTO SUNDAY. CONSIDERABLE
DIFFERENCES FROM WHERE THE MODELS AND THERE RESPECTIVE ENSEMBLES WERE
A FEW DAYS AGO, PARTICULARLY WITH THE ECMWF. THE ECMWF HAS
TRENDED ABOUT 20 MB WEAKER WITH THE LOW PRESSURE CENTER TOWARD THE
DRIER GFS AND CMC MODELS. STRONG AGREEMENT FROM IT`S ENSEMBLE MEAN
AND THE 06Z GEFS EXIST AS WELL. ALSO, MORE FEATURES ASSOCIATED WITH
THIS SYSTEM WILL BE BETTER SAMPLED BY THE UPPER AIR NETWORK,
ADDING MORE INITIAL DATA. BOTTOM LINE IS THAT CONFIDENCE CONTINUES
TO INCREASE LITTLE BY LITTLE ON EACH FORECAST PACKAGE FOR A RATHER
LIGHT EVENT FOCUSED ON SATURDAY EVENING.
SUNDAY NIGHT THROUGH TUESDAY: AS THE PREVIOUS STORM DEPARTS WE
SHOULD HAVE A DRY WINDOW SUNDAY NIGHT. SOME OF THE MID-LEVEL ENERGY
DESTINED FOR THE PREVIOUS STORM WILL STAY OVER THE SOUTHEAST AND
SPAWN ANOTHER LOW PRESSURE SYSTEM WHICH HEADS UP THE COAST FOCUSED
ON MONDAY NIGHT FOR OUR REGION. THIS IS A NEW WRINKLE IN THE MODEL
GUIDANCE TODAY AND WILL NOT GO MUCH ABOVE CHANCE POP TILL MORE
CONSISTENCY IS SHOWN. THE POCONOS AND NORTHWEST NJ HAVE A CHANCE TO
SEE MIXED PRECIPITATION. HOWEVER, A SUBSTANTIAL WARM LAYER LOOKS TO
BE IN PLACE WHICH COULD LEAD TO MIXED PRECIPITATION QUICKLY CHANGING
TO RAIN. FOR NOW GENERAL RAIN/SNOW TO RAIN FOR THE POCONOS AND ALL
RAIN ELSEWHERE. WITH THE RAIN POSSIBLE NOT MUCH SPREAD IN THE
MODELED TWO METER TEMPERATURES AND MOS GUIDANCE, DID NOT STRAY FROM
THESE ON TEMPERATURES.
TUESDAY NIGHT THROUGH CHRISTMAS EVE: A STRONG COLD FRONTAL BOUNDARY WILL
MOVE INTO THE OHIO VALLEY INTO THE DEEP SOUTH ON TUESDAY DEVELOPING A
LOW PRESSURE SYSTEM TO OUR WEST BY TUESDAY NIGHT WHICH DEEPENS AS
THE TROUGH LIKELY BECOMES NEGATIVELY TILTED. EASTERLY WINDS WILL
GRADUALLY STRENGTHEN AND SWITCH TO SOUTHEASTERLY BY WEDNESDAY
MORNING. WAA AHEAD OF THE LOW IS LIKELY TO PICK UP AS WELL WITH A
STRONG LLJ. WENT ABOVE WPC GUIDANCE ON THE WINDS. ALSO, THINK THE
WINDS DUE TO DEEPENING LOW PRESSURE MAY BE HIGHER THAN CURRENTLY
FORECASTED. THIS FORECAST DOES NOT COMMIT TO A TIME PERIOD OF
MUCH HIGHER WINDS SINCE WE`RE STILL SEVEN DAYS OUT. WITH TEMPERATURES
WELL ABOVE FREEZING, RAIN IS EXPECTED. THIS DEEPENING LOW PRESSURE
COULD PROMOTE HEAVY RAINFALL, COASTAL FLOODING AND A FEW RUMBLES
OF THUNDER DEPENDING ON THE EXACT EVOLUTION OF THE LOW PRESSURE
SYSTEM. THE FORECAST FOR THIS TIME PERIOD WILL CONTINUE TO BE
ADJUSTED AS NEW DATA BECOMES AVAILABLE WHILE LIKELY NOT SNOW, RAIN
AND WIND MAY STILL CREATE TRAVEL PROBLEMS IN THIS PERIOD. WPC
GUIDANCE ON TEMPERATURES CAPTURES THE POTENTIAL SHORT WARM-UP
WELL.
IN TERMS OF TRACK ALL OF THE MODELS AND RESPECTIVE ENSEMBLES SHOW A
SPREAD GOING UP EITHER SIDE OF THE APPALACHIANS WITH THE LOW BEING THE
STRONGEST OVER THE LAKES ON WEDNESDAY.
WITH THE FORECAST IN MIND IT DOESN`T TAKE MUCH TO GO SLIGHTLY
FORWARD IN TIME. WITH ANY LIGHT SNOW MELTING FROM THE WEEKEND AND WARM
CONDITIONS ON CHRISTMAS EVE THE PROSPECTS FOR A WHITE CHRISTMAS ARE
NOT THAT GOOD ATTM.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
A VFR 00Z TAF ISSUED.
FOR THIS EVENING AND OVERNIGHT...SOME VFR CIGS ARE LIKELY FROM
KPHL TERMINAL AREA NORTHWARD UNTIL AN UPPER AIR DISTURBANCE CLEARS
THE AREA. WE ARE NOT EXPECTING PCPN TO REACH OR IMPACT TERMINALS,
ALTHOUGH THERE MIGHT BE SOME MVFR CONDITION AT POCONO AIRPORTS DUE
TO SNOW. FARTHER TO THE SOUTH, NO CIGS ARE PREDICTED, VERY FEW
CLOUDS AT ALL.
WEST TO NORTHWEST WINDS WILL AVERAGE 10 TO 15 KNOTS. WHILE WE ARE
CARRYING GUSTS IN THE TAFS, THEY SHOULD NOT CONTINUOUSLY OCCUR.
IT WILL BE PRETTY WINDY BETWEEN 2K AND 4K (WINDS GREATER THAN 30
KTS) AND WE BELIEVE THAT WILL BE ENOUGH TO TRIGGER GUSTS REACHING
AROUND 20 KTS FROM TIME TO TIME OVERNIGHT.
ON THURSDAY. A VFR CIG IS PREDICTED TO REFORM FROM KABE-KRDG
NORTHWARD. ELSEWHERE A SCATTERED DECK OF FLAT STRATOCUMULUS CLOUDS
AROUND 4500 FEET SHOULD OCCUR. SUSTAINED WEST TO NORTHWEST WINDS
SHOULD INCREASE TO NEAR 15 KTS WITH PEAK GUSTS OF AROUND 25 KTS.
WINDS SHOULD DECREASE SECOND HALF OF THURSDAY AFTERNOON AND WE
DROPPED THE GUSTINESS AND REDUCED CLOUD COVERAGE AT THE START OF
THE EVENING.
OUTLOOK...
THURSDAY NIGHT THROUGH SATURDAY: VFR WITH INCREASING CLOUDS
SATURDAY.
SATURDAY NIGHT AND SUNDAY: SOME RESTRICTIONS TO MVFR IN LIGHT SNOW
SHOWERS AND LIGHT RAIN/SNOW SHOWER MIX FOR PHL,ILG, MIV AND ACY.
SUNDAY NIGHT: VFR.
&&
.MARINE...
SCA POSTED. SCA VERIFICATION OCCURRING MOST OF THE COAST. WINDS
SHOULD SUBSIDE SOMEWHAT THIS EVENING THEN MAY PULSE UP DURING THE
NIGHT WITH ISOLATED GUSTS 30-33 KT POSSIBLE BY MORNING. WINDS ON
THURSDAY SHOULD BE STRONGEST DURING THE MORNING THEN MAY SUBSIDE A
BIT DURING MID AND LATE AFTERNOON.
THE SCA ON DE BAY HAS BEEN EXTENDED. STRONG WINDS ARE FORECAST
ABOVE THE BOUNDARY LAYER WHICH SHOULD BECOME MORE EASILY MIXED
DOWNWARD AS THE NIGHT PROGRESSES PEAKING THURSDAY MORNING.
BUOY 44009 FULL SERVICE RESTORATION PROBABLY DELAYED TIL FEBRUARY
2015.
OUTLOOK...
WIND GUSTS CLOSE TO 25 KNOTS IN SPOTS THURSDAY NIGHT AND FRIDAY WITH
NORTHWEST FLOW. NOT ENOUGH CONFIDENCE TO EXTEND SCA ATTM. OTHERWISE,
CONDITIONS WILL BE BELOW SCA CRITERIA THROUGH MONDAY. WEAK LOW
PRESSURE PASSING TO OUR SOUTH SHOULD NOT LEAD TO SEAS HIGHER THAN
FOUR FEET ON THE OCEAN. SOUTHERLY WINDS MONDAY. WINDS SHIFTING TO
NORTH OR NORTHEAST SATURDAY INTO THE WEEKEND.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR ANZ450>455.
SMALL CRAFT ADVISORY UNTIL NOON EST THURSDAY FOR ANZ430-431.
&&
$$
SYNOPSIS...GAINES
NEAR TERM...GIGI
SHORT TERM...DRAG
LONG TERM...GAINES
AVIATION...GAINES/GIGI
MARINE...DRAG/GAINES/GIGI
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
335 AM EST TUE DEC 16 2014
...WIDESPREAD DENSE FOG SPREADING INLAND ACROSS INTERIOR NORTHEAST
FLORIDA...
.SHORT TERM...WIDESPREAD DENSE FOG CONTINUES TO AFFECT INLAND
PORTIONS OF NE FL WITH THE LEADING EDGE MOVING TO ABOUT THE HIGHWAY
301 CORRIDOR S OF BALDWIN AT 0815Z. MAY NEED TO EXPAND THE ADVISORY
E AND N BASED ON LATEST IR IMAGERY AND HI-RES GUIDANCE AND WILL
CONTINUE TO MONITOR. THINK THE HRRR GUIDANCE IS OVERDONE SHOWING
ABOUT 95% OF THE FORECAST AREA IN DENSE FOG BY 12Z-14Z. NAM12 AND TO
A LESSER EXTENT THE NMM/ARW INDICATE A MORE REALISTIC DEPICTION OF
DENSE FOG/LOW STRATUS AFFECTING NE FL (EXCEPT THE IMMEDIATE ATLC
COASTAL COUNTIES) AND EXTREME SERN GA AT 12Z.
FOR TODAY...FOG SHOULD DISSIPATE MOST LOCATIONS BY 14Z/15Z AS WARMER
SWLY FLOW DEVELOPS AHEAD OF AN APPROACHING COLD FRONT. THE FRONT WAS
LOCATED FROM ERN TN TO EXTREME SE LA AT 08Z. FRONT EXPECTED TO PUSH
THROUGH SE GA IN THE AFTN AND NE FL THIS EVENING. ANTICIPATE ISOLD
TO SCT SHOWER ACTIVITY MOVING INTO SE GA ACCOMPANYING THE FRONT BUT
LITTLE PRECIP AMOUNTS DUE TO FAST MOVEMENT OF SHOWERS AND WEAKLY
FORCED FRONT. NO THUNDER EXPECTED. HIGHS TODAY WILL HINGE ON CLOUD
COVER AS IT INCREASES AHEAD OF FRONT PASSES THROUGH. HIGHS IN
THE LOWER TO MID 70S MOST LOCATIONS. SWLY WINDS AROUND 10-15 MPH
WITH GUSTS POSSIBLY NEAR 20-25 MPH FOR A BRIEF TIME AS MIXING
MAXIMIZES AROUND THE 18Z-23Z TIME FRAME.
TONIGHT...FRONT WILL BE ACROSS COASTAL SE GA TO THE SUWANNEE VALLEY
AREA IN THE EVENING AND MOVE THROUGH REST OF NE FL BY 06Z-08Z. ISOLD
PRECIP POTENTIAL IS INDICATED FROM SUWANNEE VALLEY AREA NEWD TO
BRUNSWICK GA AND SHIFTING SEWD BUT WEAKENING QUICKLY THROUGH THE
EVENING. PARTLY TO MOSTLY CLOUDY IN THE EVENING...BECOMING MOSTLY
CLEAR FROM NW TO SE AFTER MIDNIGHT. MIN TEMPS FALL INTO THE 40S
AGAIN WITH LIGHT NWLY FLOW. COLDEST TEMPS IN THE SE GA AS COOL SFC
HIGH PRES BUILDS IN FROM THE NW.
WED THROUGH THU NIGHT...STACKED HIGH PRESSURE WILL BUILD OVER THE
REGION BRINGING MOSTLY CLEAR TO PARTLY CLOUDY SKIES WITH PASSING
HIGH CLOUDS WED NIGHT THROUGH THURSDAY NIGHT. NEAR SEASONAL TEMPS
EXPECTED WITH HIGHS IN THE 60S AND A DRY WNW FLOW 10 MPH OR LESS.
MIN TEMPS WILL RANGE IN THE UPPER 30S/LOWER 40S INLAND TO MID/UPPER
40S ALONG THE ST JOHNS RIVER BASIN/ATLANTIC COAST WED NIGHT AND
GIVEN PASSING HIGH CLOUDS FROST DEVELOPMENT LIKELY TO BE PATCHY AT
BEST OVER INLAND LOCATIONS. MIN TEMPS WILL BE A BIT WARMER THU NIGHT
WITH VALUES IN LOW/MID 40S INLAND TO UPPER 40S/LOW 50S TOWARD THE
ATLANTIC AS LOW LEVEL WINDS VEER NNE AS A WEAK COASTAL TROUGH/HIGH
PRESSURE WEDGE SCENARIO EDGES SOUTHWARD DOWN THE SE ATLANTIC
SEABOARD. WITH INCREASING TEMPS AND SHALLOW MOISTURE...SOME LATE
NIGHT FOG WILL BE POSSIBLE THU NIGHT.
.LONG TERM...FRI THROUGH TUE...
EXTENDED MODELS (GFS/ECMWF/DGEX) IN GOOD AGREEMENT THROUGH FRI NIGHT
WITH MOSTLY DRY CONDITIONS AND WARMER TEMPS AS WINDS VEER SSW AHEAD
OF AN APPROACHING GULF COAST STORM SYSTEM. COULD SEE A LATE AFTN
SHOWER NEAR THE ATLANTIC COAST AND ALONG THE ALTAMAHA RIVER BASIN
WHERE A COASTAL TROUGH WILL ELONGATE W-E AND MORPH INTO A WARM FRONT
AHEAD OF THE APPROACHING STORM SYSTEM. HIGHS FRI WILL RANGE IN THE
60S INLAND WITH MILD OVERNIGHT LOWS FRI NIGHT IN THE UPPER 40S TO
LOW/MID 50S WITH SOME LATE NIGHT STRATUS/FOG MOVING INLAND FROM THE
GULF.
SAT & SAT NIGHT...EXTENDED GUIDANCE IS IN BETTER AGREEMENT SAT WITH
THE APPROACH OF LOW PRESSURE TREKKING EASTWARD ALONG THE GULF COAST
STATES. THE 00Z ECMWF SLOWED DOWN A BIT AND HAS A WEAKER PARENT
UPPER LEVEL TROUGH COMPARED TO PREVIOUS RUNS AND IS STARTING TO COME
INTO BETTER AGREEMENT WITH THE WEAKER GFS SOLUTION. FOR THIS PACKAGE
ADVERTISED PRE-FRONTAL SHOWERS MOVING ACROSS THE LOCAL FORECAST AREA
MAINLY SAT AFTN WITH 40-50% RAIN CHANCES ACROSS THE ALTAMAHA RIVER
BASIN AND SUWANNEE RIVER VALLEY...DOWN TO 20% SAT AFTN FOR FLAGLER
COUNTY. DYNAMICS/LIFT PUSH OFF TO THE NE OF THE LOCAL AREA SAT NIGHT
LEAVING A STALLING FRONTAL ZONE SAGGING SOUTHWARD OVER THE LOCAL
FORECAST AREA. COULD SEE A FEW LINGERING SHOWERS AND ADVERTISED 20%
AT THIS TIME SAT NIGHT.
SUN-TUE...SUN WILL BE COOLER AND MOSTLY DRY. THE GFS IS FASTER
DEVELOPING AN ISENTROPIC RAINFALL EVENT ACROSS NE FL SUN
NIGHT...WHILE THE ECMWF IS IN BETTER AGREEMENT WITH THE EVENT
TRANSPIRING LATE MON INTO TUE NIGHT...WITH A WIDESPREAD RAINFALL
ACROSS NE FL THROUGH EARLY TUE MORNING AS AN UPPER LEVEL TROUGH
DEEPENS A SFC LOW ALONG THE STALLED FRONTAL ZONE EAST OF THE SE
ATLANTIC COAST EARLY TUE. LOOKS LIKE A COOL AND WET RAINFALL EVENT
WITH THE POTENTIAL FOR DECENT AMOUNTS ALONG AND S OF THE I-10
CORRIDOR. THE WEATHER PREDICTION CENTER HAS AROUND A HALF A INCH
ADVERTISED FOR N FL AND 0.25-0.50" FOR SE GA SUN-TUE WITH LOCALLY
HIGHER AMOUNTS. THIS WOULD BE THE FIRST WIDESPREAD WETTING RAINFALL
EVENT SINCE NOV 25-26TH.
TEMPS WILL RANGE NEAR TO SLIGHTLY BELOW NORMAL WITH NO FREEZES.
HIGHS IN THE UPPER 50S-MID 60S AND LOWS IN THE 40S/LOWER 50S. NO
FREEZING TEMPS EXPECTED AT THIS TIME.
&&
.AVIATION...VLFIR CONDITIONS WILL CONTINUE AT GNV THROUGH 13Z/14Z...
THEN VFR PREVAILS AFTERWARD. SOME UNCERTAINTY ON HOW MUCH OF THIS
FOG WILL AFFECT THE JAX METRO TAFS BUT LIFR POSSIBLE BY 09Z-13Z AS
LEADING EDGE OF ADVECTIVE FOG MOVES FURTHER E TO NE. CONTINUED TO
LEAVE FOG OUT OF SSI TAF AT THIS TIME BASED ON MOST OF THE MODEL
GUIDANCE. VFR CIGS LIKELY FOR A PERIOD OF TIME IN ASSOCD WITH
FRONTAL PASSAGE LATER TODAY AND PROBABILITIES OF MVFR CIGS LOOK TO
BE LESS THAN 30% SO CONFIDENCE IS LOW ATTM. MAIN WINDOW OF POSSIBLE
MVFR CIG WOULD BE FROM ABOUT 22Z TO 06Z. WINDS TODAY SWLY INCREASING
TO NEAR 10-12G20KT AT TIMES...DECREASING AND SHIFTING TO W AND NW
LATER TONIGHT.
&&
.MARINE...SWLY WINDS WILL CONTINUE AROUND 10-15 KT TODAY AND
INCREASE FROM THE W AND THEN NW TONIGHT IN ASSOCD WITH FRONTAL
PASSAGE. HIGH CONFIDENCE ON SCEC CONDS FOR MAINLY THE OUTER WATERS
TONIGHT WITH SEAS OF ABOUT 5 FT AT THE OUTER FRINGES OF THE MARINE
WATERS. WINDS AND SEAS DECREASE WED THROUGH THU AS SFC HIGH PRES
BUILDS IN. CONDITIONS WILL LIKELY WORSEN TO CAUTION LEVELS ONCE
AGAIN FOR THE UPCOMING WEEKEND AS ANOTHER COLD FRONT AFFECTS THE
REGION.
RIP CURRENTS: LOW RISK TODAY THROUGH WEDNESDAY WITH LOW SWELL
HEIGHTS AND OFFSHORE FLOW.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 72 41 62 38 / 30 10 0 0
SSI 70 46 60 44 / 10 20 0 0
JAX 74 45 64 41 / 10 10 0 0
SGJ 72 49 62 45 / 10 10 0 0
GNV 73 47 67 41 / 10 10 0 0
OCF 73 47 68 41 / 10 10 0 0
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR ALACHUA-
BAKER-BRADFORD-COLUMBIA-GILCHRIST-HAMILTON-MARION-SUWANNEE-
UNION.
GA...NONE.
AM...NONE.
&&
$$
SHASHY/ENYEDI
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1228 PM EST TUE DEC 16 2014
.PREV DISCUSSION... /ISSUED 300 AM EST TUE DEC 16 2014/
SHORT TERM /TODAY THROUGH WEDNESDAY/...
ONGOING OVERNIGHT RAIN SHOWERS ACROSS THE AREA WILL CONTINUE THROUGH
LATE MORNING AND EARLY AFTERNOON ACROSS THE CWA AS FRONT PUSHES INTO
THE STATE. INSTABILITY CONTINUES TO BE LIMITED...AND ALTHOUGH
PORTIONS THERE IS A HISTORY OF SOME SMALL AMOUNTS OF MUCAPE AND
LIGHTNING OVER ALABAMA...THUS FAR HAVE NOT HAD ANY LIGHTNING IN THIS
ACTIVITY. AT BEST EXPECT WIDESPREAD 0.25 INCHES OF ADDITIONAL
RAINFALL...WITH HIGHEST AMOUNTS ACROSS NORTHEAST GEORGIA AS THE AREA
OF RAIN TRANSITIONS FARTHER EAST.
ALTHOUGH HRRR PUSHES RAIN SOUTH AND EAST OF THE CWA BY NOON...A FEW
OF THE SHORT TERM HI-RES MODELS CONTINUE TO ADVERTISE RESIDUAL
MOISTURE ACROSS THE AREA...PARTICULARLY FAR NORTH GEORGIA...SO HAVE
KEPT MENTION OF SLIGHT CHANCE POPS UNTIL 21-22Z.
THE PARENT LOW PRESSURE SYSTEM LIFTS OVER THE EASTERN GREAT LAKES
REGION LATE TONIGHT WITH ZONAL FLOW ALOFT RETURNING TO THE REGION
THROUGH THURSDAY MORNING.
HAVE GENERALLY GONE WITH A BLEND FOR TEMPERATURES...WITH NEAR
SEASONAL TEMPERATURES THROUGH THE SHORT TERM.
31
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
BETTER AGREEMENT FOR THE WEEKEND SYSTEM AMONGST THE LONG TERM
MODELS.
SHORT WAVE STILL ON TRACK FOR OVERNIGHT WEDNESDAY INTO THURSDAY
MORNING. ANY PRECIP CHANCES WITH THIS SYSTEM SHOULD BE ON
THURSDAY...WITH ONLY SOME SCATTERED SPRINKLES IN THE NORTHWEST
OVERNIGHT WEDNESDAY. WEDNESDAY MIN TEMPS SHOULD BE WARM ENOUGH NOT
TO CAUSE ANY PTYPE ISSUES EARLY THURSDAY MORNING.
THE NEXT SYSTEM TO IMPACT THE CWFA IS IN THE FRIDAY THROUGH
SATURDAY TIME FRAME. MODELS HAVE COME INTO BETTER AGREEMENT WITH
THE EVOLUTION OF THIS SYSTEM AS COMPARED TO YESTERDAYS RUNS AT
THIS TIME. THE ECMWF HAS A WEAKER 500MB SYSTEM AND THE GFS HAS
NUDGED ITS SURFACE LOW FURTHER SOUTH. ISENTROPICALLY INDUCED
RAINFALL SHOULD BEGIN DURING THE DAY FRIDAY AND SPREAD NORTHEAST
THROUGH THE DAY. CURRENTLY...THE HIGHEST CHANCES FOR PRECIP WILL
BE FRIDAY NIGHT INTO SATURDAY AS LOW PRESSURE TRAVERSES THE AREA.
THE RAIN CHANCES WILL BEGIN TO TAPER OFF EARLY SATURDAY
EVENING. AS FAR AS THE RASN CHANCES FOR THE HIGHER TERRAIN LATE
SATURDAY/EARLY SUNDAY...THE POTENTIAL IS STILL THERE.
HOWEVER...CHANCES STILL REMAIN SMALL. TEMPS IN THE MODELS ARE
WARMER BY A FEW DEGREES AND THE MODELS CAN BE TOO SLOW TO CUT OFF
PRECIP BEHIND A COLD FRONT/LOW PRESSURE. WILL CONTINUE WITH
PERSISTENCE AND KEEP MENTION IN THE FORECAST.
HIGH PRESSURE BRIEFLY BUILDS INTO THE CWFA FOR MONDAY INTO EARLY
TUESDAY WITH THE NEXT SYSTEM IMPACTING THE CWFA TUESDAY NIGHT INTO
WEDNESDAY.
NLISTEMAA
&&
.AVIATION...
18Z UPDATE...
MAINLY VFR THROUGH THE PERIOD. SOME LINGERING MVFR CIGS NEAR
MCN/AHN BUT RAPID IMPROVEMENT EXPECTED. METRO TAFS MAY SEE SOME
SCT TO POSSIBLY BKN MVFR WEDNESDAY MORNING...BUT CURRENT THINKING
IS CIGS SHOULD GENERALLY STAY NORTH OF METRO TAFS. W TO NW WINDS
THROUGH THE PERIOD AROUND 10KT AND GUSTY THIS AFTERNOON...DROPPING
BELOW 10KT OVERNIGHT.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM-HIGH ON NO CIGS WEDNESDAY MORNING.
HIGH ON ALL OTHER ELEMENTS.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 60 36 56 37 / 60 0 0 5
ATLANTA 61 38 55 38 / 40 0 0 5
BLAIRSVILLE 55 34 52 32 / 20 0 0 5
CARTERSVILLE 58 35 53 35 / 10 0 0 5
COLUMBUS 66 37 58 38 / 40 0 0 5
GAINESVILLE 56 36 54 37 / 40 0 0 5
MACON 69 36 60 36 / 30 0 0 5
ROME 57 35 53 35 / 10 0 0 5
PEACHTREE CITY 62 34 56 35 / 50 0 0 5
VIDALIA 69 42 62 39 / 20 0 0 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
300 AM EST TUE DEC 16 2014
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
ONGOING OVERNIGHT RAIN SHOWERS ACROSS THE AREA WILL CONTINUE THROUGH
LATE MORNING AND EARLY AFTERNOON ACROSS THE CWA AS FRONT PUSHES INTO
THE STATE. INSTABILITY CONTINUES TO BE LIMITED...AND ALTHOUGH
PORTIONS THERE IS A HISTORY OF SOME SMALL AMOUNTS OF MUCAPE AND
LIGHTNING OVER ALABAMA...THUS FAR HAVE NOT HAD ANY LIGHTNING IN THIS
ACTIVITY. AT BEST EXPECT WIDESPREAD 0.25 INCHES OF ADDITIONAL
RAINFALL...WITH HIGHEST AMOUNTS ACROSS NORTHEAST GEORGIA AS THE AREA
OF RAIN TRANSITIONS FARTHER EAST.
ALTHOUGH HRRR PUSHES RAIN SOUTH AND EAST OF THE CWA BY NOON...A FEW
OF THE SHORT TERM HI-RES MODELS CONTINUE TO ADVERTISE RESIDUAL
MOISTURE ACROSS THE AREA...PARTICULARLY FAR NORTH GEORGIA...SO HAVE
KEPT MENTION OF SLIGHT CHANCE POPS UNTIL 21-22Z.
THE PARENT LOW PRESSURE SYSTEM LIFTS OVER THE EASTERN GREAT LAKES
REGION LATE TONIGHT WITH ZONAL FLOW ALOFT RETURNING TO THE REGION
THROUGH THURSDAY MORNING.
HAVE GENERALLY GONE WITH A BLEND FOR TEMPERATURES...WITH NEAR
SEASONAL TEMPERATURES THROUGH THE SHORT TERM.
31
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
BETTER AGREEMENT FOR THE WEEKEND SYSTEM AMONGST THE LONG TERM
MODELS.
SHORT WAVE STILL ON TRACK FOR OVERNIGHT WEDNESDAY INTO THURSDAY
MORNING. ANY PRECIP CHANCES WITH THIS SYSTEM SHOULD BE ON
THURSDAY...WITH ONLY SOME SCATTERED SPRINKLES IN THE NORTHWEST
OVERNIGHT WEDNESDAY. WEDNESDAY MIN TEMPS SHOULD BE WARM ENOUGH NOT
TO CAUSE ANY PTYPE ISSUES EARLY THURSDAY MORNING.
THE NEXT SYSTEM TO IMPACT THE CWFA IS IN THE FRIDAY THROUGH
SATURDAY TIME FRAME. MODELS HAVE COME INTO BETTER AGREEMENT WITH
THE EVOLUTION OF THIS SYSTEM AS COMPARED TO YESTERDAYS RUNS AT
THIS TIME. THE ECMWF HAS A WEAKER 500MB SYSTEM AND THE GFS HAS
NUDGED ITS SURFACE LOW FURTHER SOUTH. ISENTROPICALLY INDUCED
RAINFALL SHOULD BEGIN DURING THE DAY FRIDAY AND SPREAD NORTHEAST
THROUGH THE DAY. CURRENTLY...THE HIGHEST CHANCES FOR PRECIP WILL
BE FRIDAY NIGHT INTO SATURDAY AS LOW PRESSURE TRAVERSES THE AREA.
THE RAIN CHANCES WILL BEGIN TO TAPER OFF EARLY SATURDAY
EVENING. AS FAR AS THE RASN CHANCES FOR THE HIGHER TERRAIN LATE
SATURDAY/EARLY SUNDAY...THE POTENTIAL IS STILL THERE.
HOWEVER...CHANCES STILL REMAIN SMALL. TEMPS IN THE MODELS ARE
WARMER BY A FEW DEGREES AND THE MODELS CAN BE TOO SLOW TO CUT OFF
PRECIP BEHIND A COLD FRONT/LOW PRESSURE. WILL CONTINUE WITH
PERSISTENCE AND KEEP MENTION IN THE FORECAST.
HIGH PRESSURE BRIEFLY BUILDS INTO THE CWFA FOR MONDAY INTO EARLY
TUESDAY WITH THE NEXT SYSTEM IMPACTING THE CWFA TUESDAY NIGHT INTO
WEDNESDAY.
NLISTEMAA
&&
AVIATION...
06Z UPDATE...
LIGHT RAIN SHOWERS CONTINUE ACROSS NORTH GEORGIA THIS
MORNING...AND EXPECT PRECIP TO TAPER OFF ACROSS THE ATL AND CSG
AREAS BY 13Z...AND AHN/MCN BY 15-16Z. CONDITIONS CONTINUE TO
DEGRADE WITH THIS ACTIVITY...WITH IFR EXPECTED BY 11Z...WITH SLOW
IMPROVEMENT THROUGH LATE MORNING. VFR ANTICIPATED BY THE AFTERNOON
WITH DEGRADING CONDITIONS POSSIBLE AGAIN AFTER 06Z WEDNESDAY.
WINDS WILL SHIFT TO THE W-WNW AND INCREASE TO 8-15KT WITH 15-20KT
GUSTS BEHIND THE FRONT.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON CIGS THROUGH 13Z.
LOW ON CIGS AFTER 06Z WEDNESDAY.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
31
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 61 38 58 35 / 30 0 0 0
ATLANTA 59 39 55 37 / 30 0 0 0
BLAIRSVILLE 54 34 53 31 / 30 10 5 5
CARTERSVILLE 57 36 53 34 / 20 0 0 5
COLUMBUS 66 38 60 38 / 30 0 0 0
GAINESVILLE 56 38 55 36 / 30 0 0 5
MACON 67 38 61 35 / 30 0 0 0
ROME 56 36 53 34 / 20 0 5 10
PEACHTREE CITY 61 37 57 35 / 30 0 0 0
VIDALIA 68 42 61 38 / 20 10 0 0
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...31
LONG TERM....NLISTEMAA
AVIATION...31
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
909 PM CST Wed Dec 17 2014
.UPDATE...
ISSUED AT 909 PM CST WED DEC 17 2014
Have already made one adjustment to cloud cover since it is not
clearing as fast as originally expected. Will be making another
adjustment for the same thing with high clouds advecting in from
the southwest. Pcpn is moving across MO and still expected to
arrive in western IL in the morning. Forecast still has good
handle on this. Most of forecast looks fine, but will be updating
to reflect current cloud trends. Update coming shortly.
&&
.SHORT TERM...(Tonight)
ISSUED AT 245 PM CST WED DEC 17 2014
19z/1pm satellite imagery continues to show overcast conditions
across much of central Illinois: however, the clouds are beginning
to erode northwest of the Illinois River. While HRRR guidance has
not been particularly useful in the short-term, satellite trends
suggest skies will partially clear across all but the far E/NE KILX
CWA by early evening. After a period of mostly clear skies early
tonight, clouds will once again begin increasing in advance of the
next storm system, which is currently evident on water vapor imagery
over west Texas. Quite a bit of precip and even some thunder is
occurring ahead of this wave over Oklahoma/Texas: however, it is
expected to weaken as it lifts northeastward into the region on
Thursday. It will also be coming into a dry airmass beneath a
prevailing surface ridge axis. Forecast soundings show gradual
moistening from the top-down later tonight, but the lowest levels
below 850mb will remain quite dry through 12z. As a result, have
maintained a dry forecast through the overnight hours. Due to the
initially clear skies and low dewpoints, have gone a couple of
degrees below MAV guidance for lows tonight, with readings dropping
into the teens and lower 20s.
&&
.LONG TERM...(Thursday through Wednesday)
ISSUED AT 245 PM CST WED DEC 17 2014
Upper flow will be zonal for next few days, with weak waves moving
east through flow. Moisture channel data and upper air shows initial
wave to affect region over NM this morning. This system to
continue tracking to the northeast, pushing some overrunning pcpn
into MO and southern 1/2 of IL for late tonight into Thursday. Weak
vort lobe and isentropic lift to be enough to move the light snow
into southern 1/2 of CWA in the morning, but wave moving fast enough
to only affect the morning. Mainly less than half inch.
Next wave to move into region for Friday night and Saturday morning
and the area of lift with this one is farther south, mainly over
southeast cwa. Again, some light snow possible.
Upper flow starts to change on late in weekend and by Monday, flow
is northwest. Digging upper trough over Great Lakes with upper low
closing off by Monday night. This will bring some initial pcpn into
the region ahead of cold front that moves through Tuesday.
Temperatures however, are only cold enough for possible mixture
until post frontal on Tuesday night and Wednesday. Therefore no snow
accumulation. However by Tues night to Wed, only minor vort lobes
rotating around the closed upper low in the cold air, so chance of
light snow accumulations only.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 536 PM CST WED DEC 17 2014
Some clearing has occurred at PIA and SPI, but clouds still remain
at BMI, DEC, and CMI. Question is that now that the sun is gone,
when will clouds push further east, clearing at the last three TAF
sites, or will it even clear there at all. All models continue to
clear lower clouds so will scatter the low clouds out later this
evening at those sites. However, all sites will be covered with
cirrus overnight. By morning, mid clouds around 8-12kft will move
into the area in advance of the next weather system. Based on the
movement of the system, very light snow will begin at SPI around
15z with cigs around 3.5kft, with vis around 5sm. The other 4
sites will not see any snow, but cigs will drop to 4-6kft. The
system will dissipate as it moves into the area, which will
improve conditions by late afternoon at all sites. Lower clouds
will diminish and then broken cirrus will be left at all sites.
Winds will be light and variable through the period.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Auten
SHORT TERM...Barnes
LONG TERM...Goetsch
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
556 PM CST WED DEC 17 2014
.SHORT TERM...
230 PM CST
THROUGH FRIDAY...
RELATIVELY BENIGN WEATHER ON TAP IN THE NEAR TERM UNDER THE
INFLUENCE OF HIGH PRESSURE WHICH WILL REMAIN OVER THE REGION INTO
THE WEEKEND. SURFACE RIDGE EXTENDS FROM MANITOBA INTO THE LOWER
MISSISSIPPI VALLEY THIS AFTERNOON WHILE ALOFT A SHEARED VORT MAX IS
DIGGING SOUTHEAST ACROSS FAR NORTHERN ILLINOIS. SOUNDINGS INDICATE
STEEP LOW LEVEL LAPSE RATES UP TO AROUND 900MB THIS AFTERNOON AND
RADAR IMAGERY DOES SHOW SIGNS OF SOME CONVECTIVE ROLLS WITH VERY
WEAK WIND PARALLEL RETURNS. WITH THESE INGREDIENTS IN PLACE...A FEW
FLURRIES HAVE BEEN NOTED ACROSS THE AREA...BUT NOTHING OF
CONSEQUENCE. ANY FLURRIES SHOULD TAPER BY MID-LATE AFTERNOON AS
INVERSION HEIGHTS BEGIN TO COME DOWN IN RESPONSE TO MODERATE TO
STRONG MID LEVEL HEIGHT RISES BEHIND DEPARTING SHORTWAVE. STRATUS
DECK REMAINS IN PLACE TODAY BUT HAS BEGUN TO THIN AND ERODE NEAR
THE WESTERN COUNTIES. ANY PEAKS OF SUNSHINE TODAY THOUGH ARE
EXPECTED TO BE BRIEF AS MID LEVEL CLOUD COVER INCREASES FROM THE
NORTH AS A WEAK TROUGH EMBEDDED ON THE EASTERN PERIPHERY OF THE
HIGH SAGS SOUTH ACROSS LAKE MICHIGAN...AND FROM THE SOUTHWEST AS
ANOTHER SHORTWAVE TROUGH CURRENTLY LIFTING ACROSS THE PANHANDLES
OF TX/OK PUSHES ACROSS CENTRAL ILLINOIS MIDDAY THURSDAY. PRECIP
WITH THIS SYSTEM IS EXPECTED TO STAY SOUTH OF THE CWA...TAPERING
AS IT OVERRIDES THE SURFACE RIDGE. CLOUD COVER MAY CONTINUE TO
REMAIN LOCKED IN UNDER THE INVERSION FRIDAY...BUT OTHERWISE EXPECT
VERY LIGHT WINDS AND DRY CONDITIONS ON SQUARELY UNDER THE SURFACE
HIGH.
DEUBELBEISS
&&
.LONG TERM...
230 PM CST
FRIDAY NIGHT THROUGH THURSDAY...
HIGH PRESSURE WILL CONTINUE TO SLOWLY SHIFT EAST ACROSS THE REGION
OVER THE WEEKEND WITH RETURN FLOW BRINGING WARMER TEMPERATURES
ESPECIALLY BY SUNDAY. MEANWHILE...THE PATTERN IS PROGGED TO BEGIN
AMPLIFYING BY LATE IN THE WEEKEND AS LONGWAVE TROUGH DEEPENS ACROSS
THE MID SECTION OF THE COUNTRY DOWNSTREAM OF A BUILDING RIDGE ALONG
THE WEST COAST. THE JET STREAM WILL DIVE TOWARDS THE GULF STATES BY
TUESDAY WITH SURFACE LOW DEEPENING IN RESPONSE EARLY NEXT WEEK.
THERE REMAIN SIGNIFICANT DIFFERENCES AS WELL AS RUN-TO-RUN
VARIABILITY IN THE TIMING AND TRACK OF THE LOW AS IT LIFTS ACROSS
THE MIDWEST MIDWEEK...WITH COMPLICATIONS AS THE MODELS DEAL WITH
PHASING THE SOUTHERN LOW WITH A CLIPPER LIKE SYSTEM. WILL
CERTAINLY HAVE TO KEEP AN EYE ON THE POTENTIAL FOR ACCUMULATING
SNOW TUESDAY INTO WEDNESDAY OVER THE NEXT SEVERAL DAYS AS MODELS
HOPEFULLY BEGIN TO HONE IN ON A SOLUTION. A RETURN TO BELOW NORMAL
CONDITIONS SEEMS LIKELY FOR THE LATTER HALF OF THE WEEK.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* MVFR CEILINGS TONIGHT AND POSSIBLY FOR A TIME TOMORROW
KMD
//DISCUSSION...UPDATED 00Z...
MVFR CLOUD DECK AROUND 2000-2500 FT IS SHOWING SIGNS OF CLEARING
IN SW WI. GUIDANCE IS MIXED ON WHEN IT WILL SCATTER OUT...WITH
MUCH OF THS MOS GUIDANCE SUGGESTING IT WILL DO SO AROUND 4Z. THE
RUC IS HANGING ONTO CLOUDS THROUGH ABOUT 8Z. WILL HOLD THE
PESSIMISTIC ROUTE FOR NOW TO SEE HOW THE CLOUDS CONTINUE CLEARING
AFTER SUNSET.
OTHERWISE GUIDANCE REMAINS MIXED AS TO WHETHER LOWER CLOUDS WILL
RETURN FROM THE WAVE DROPPING SOUTH THROUGH N WI. FEELING IS THAT
THESE CLOUDS WILL NOT MAKE IT DOWN AT THIS POINT AS WE GET MORE
WESTERLY FLOW PUSHING ALOFT BUT THIS WILL BEAR WATCHING.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH THAT MVFR WILL CLEAR OVERNIGHT BUT LOW ON TIMING AND ON IF
IT WILL RETURN TOMORROW
KMD
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY AND SATURDAY...DRY WITH VFR LIKELY...THOUGH MVFR POSSIBLE. LIGHT AND
VARIABLE WINDS.
SUNDAY...DRY. MVFR POSSIBLE. SOUTH WINDS.
MONDAY...CHANCE OF RAIN. MVFR LIKELY. GUSTY SOUTH WINDS...POSSIBLY
TURNING SOUTHEAST.
TUESDAY...CHANCE OF RAIN MIXED WITH SNOW. IFR POSSIBLE. SOUTHWEST
WINDS.
KMD
&&
.MARINE...
210 PM CST
THE LOW PRESSURE THAT PASSED THROUGH THE GREAT LAKES REGION OVER THE
PAST COUPLE DAYS IS IN THE PROCESS OF MERGING WITH ANOTHER LOW OVER
THE NEW ENGLAND COAST. THIS LOW WILL GRADUALLY DEEPEN AND SLOWLY
MOVE NORTH ALONG THE NEW ENGLAND COAST AS HIGH PRESSURE SPREADS FROM
THE NORTHERN PLAINS AND ACROSS THE WESTERN GREAT LAKES BY THURSDAY
MORNING. WINDS ARE SLOWLY SUBSIDING OVER THE LAKE...BUT A SECONDARY
TROUGH AND SURGE OF COOLER AIR MOVING DOWN THE LAKE THIS AFTERNOON
AND EVENING WILL KEEP RELATIVELY BRISK NLY-NLWY WINDS OVER THE LAKE
THROUGH THE NIGHT TONIGHT. WINDS SHOULD WEAKEN TO THE 10-15KT RANGE
THURSDAY NIGHT AND FRIDAY AS THE HIGH GRADUALLY SPREADS EAST...WHILE
MAINTAINING A NLY DIRECTION. THE HIGH WILL SPREAD ACROSS LAKE
MICHIGAN THURSDAY NIGHT AND FRIDAY...LEADING TO MORE LGT/VRBL WINDS
OVER THE LAKE. HIGH PRESSURE WILL VERY SLOWLY SPREAD EWD...BUT
STILL CONTROLLING FLOW OVER THE LAKE...KEEPING WINDS GENERALLY LIGHT
AND VARIABLE INTO THE WEEKEND. BY SUNDAY...THE HIGH WILL FINALLY
PUSH EAST OF LAKE MICHIGAN AS A TROUGH OF LOW PRESSURE DEVELOPS OVER
THE NORTHERN PLAINS. THIS WILL SET UP INCREASING SLY FLOW OVER THE
LAKE BY SUNDAY. A DEVELOPING LOW IS EXPECTED TO TRACK ACROSS THE
NRN PLAINS SUNDAY NIGHT AND MONDAY...REACHING THE MIDDLE MISSISSIPPI
VALLEY BY TUESDAY. THIS WILL KEEP GENERALLY SOUTHERLY WINDS OVER
THE LAKE THROUGH EARLY NEXT WEEK.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 10 AM THURSDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
536 PM CST Wed Dec 17 2014
.SHORT TERM...(Tonight)
ISSUED AT 245 PM CST WED DEC 17 2014
19z/1pm satellite imagery continues to show overcast conditions
across much of central Illinois: however, the clouds are beginning
to erode northwest of the Illinois River. While HRRR guidance has
not been particularly useful in the short-term, satellite trends
suggest skies will partially clear across all but the far E/NE KILX
CWA by early evening. After a period of mostly clear skies early
tonight, clouds will once again begin increasing in advance of the
next storm system, which is currently evident on water vapor imagery
over west Texas. Quite a bit of precip and even some thunder is
occurring ahead of this wave over Oklahoma/Texas: however, it is
expected to weaken as it lifts northeastward into the region on
Thursday. It will also be coming into a dry airmass beneath a
prevailing surface ridge axis. Forecast soundings show gradual
moistening from the top-down later tonight, but the lowest levels
below 850mb will remain quite dry through 12z. As a result, have
maintained a dry forecast through the overnight hours. Due to the
initially clear skies and low dewpoints, have gone a couple of
degrees below MAV guidance for lows tonight, with readings dropping
into the teens and lower 20s.
&&
.LONG TERM...(Thursday through Wednesday)
ISSUED AT 245 PM CST WED DEC 17 2014
Upper flow will be zonal for next few days, with weak waves moving
east through flow. Moisture channel data and upper air shows initial
wave to affect region over NM this morning. This system to
continue tracking to the northeast, pushing some overrunning pcpn
into MO and southern 1/2 of IL for late tonight into Thursday. Weak
vort lobe and isentropic lift to be enough to move the light snow
into southern 1/2 of CWA in the morning, but wave moving fast enough
to only affect the morning. Mainly less than half inch.
Next wave to move into region for Friday night and Saturday morning
and the area of lift with this one is farther south, mainly over
southeast cwa. Again, some light snow possible.
Upper flow starts to change on late in weekend and by Monday, flow
is northwest. Digging upper trough over Great Lakes with upper low
closing off by Monday night. This will bring some initial pcpn into
the region ahead of cold front that moves through Tuesday.
Temperatures however, are only cold enough for possible mixture
until post frontal on Tuesday night and Wednesday. Therefore no snow
accumulation. However by Tues night to Wed, only minor vort lobes
rotating around the closed upper low in the cold air, so chance of
light snow accumulations only.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 536 PM CST WED DEC 17 2014
Some clearing has occurred at PIA and SPI, but clouds still remain
at BMI, DEC, and CMI. Question is that now that the sun is gone,
when will clouds push further east, clearing at the last three TAF
sites, or will it even clear there at all. All models continue to
clear lower clouds so will scatter the low clouds out later this
evening at those sites. However, all sites will be covered with
cirrus overnight. By morning, mid clouds around 8-12kft will move
into the area in advance of the next weather system. Based on the
movement of the system, very light snow will begin at SPI around
15z with cigs around 3.5kft, with vis around 5sm. The other 4
sites will not see any snow, but cigs will drop to 4-6kft. The
system will dissipate as it moves into the area, which will
improve conditions by late afternoon at all sites. Lower clouds
will diminish and then broken cirrus will be left at all sites.
Winds will be light and variable through the period.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Goetsch
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
314 PM CST TUE DEC 16 2014
.SHORT TERM...
313 PM CST
TONIGHT THROUGH FRIDAY...
FILLING SURFACE LOW WAS OFF TO OUR EAST ACROSS THE CENTRAL GREAT
LAKES THIS AFTERNOON...BENEATH WEAKENING UPPER LEVEL LOW WHICH IS IN
THE PROCESS OF MERGING WITH STRONG DIGGING SHORT WAVE OVER THE UPPER
MISSISSIPPI VALLEY. THIS SECOND WAVE IS PROGGED TO SHEAR SOUTHEAST
ACROSS THE REGION TO THE EAST-SOUTHEAST AS IT REDEVELOPS INTO
REMNANT UPPER TROUGH TO THE EAST. VISIBLE SATELLITE IMAGERY SHOWS
MOST OF THE DEEPER CLOUD COVER HAS MOVED OFF TO THE EAST OF THE
FORECAST AREA...ALONG WITH THE BRUNT OF THE RADAR DETECTABLE
PRECIPITATION. EXPECT SOME PATCHY LIGHT RAIN/DRIZZLE AND PERHAPS A
FEW WET FLURRIES TO GRADUALLY END ACROSS THE AREA OVER THE NEXT FEW
HOURS AS MID-LEVELS CONTINUE TO DRY OUT...WITH 12Z RAOBS FROM
UPSTREAM LOCATIONS SUCH AS ABR AND OAX INDICATIVE OF MUCH DRIER AIR
ABOVE THE BOUNDARY LAYER. OTHERWISE...BLUSTERY WEST-NORTHWEST WINDS
WILL CONTINUE TO PULL COLDER AND DRIER AIR INTO THE AREA TONIGHT
WITH WINDS SLOW TO DIMINISH DUE TO LINGERING SURFACE TROUGHING
ACROSS THE UPPER MIDWEST. THOUGH REMAINING MOISTURE WILL BE SHALLOW
IT APPEARS CLOUD COVER WILL LINGER AT LEAST INTO EARLY WEDNESDAY
BEFORE STRONGER SUBSIDENCE CAN ERODE AND SCATTER CLOUDS MORE
EFFECTIVELY. DESPITE CLOUDS...UPSTREAM TEMPS ACROSS EASTERN IA ARE
ONLY IN THE LOW TO MID 20S AT THIS HOUR...SETTING THE STAGE FOR
CHILLIER TEMPS TONIGHT.
SHEARED MID-LEVEL VORTICITY AXIS FROM SHEARING UPPER MIDWEST SHORT
WAVE REMAINS OVER AREA WEDNESDAY..THOUGH HEIGHT RISES DO DEVELOP AS
THE NEW UPPER LOW DEEPENS OVER NEW ENGLAND. THIS ALLOWS THE GRADIENT
TO WEAKEN MORE QUICKLY ESPECIALLY DURING THE AFTERNOON AND
CONTINUING WEDNESDAY NIGHT AS SURFACE HIGH PRESSURE RIDGE MOVES
SLOWLY INTO WESTERN AND CENTRAL ILLINOIS. GUIDANCE DOES DEPICT A
SHORT WAVE APPROACHING FROM THE SOUTHERN PLAINS/LOWER MISSOURI
VALLEY AREA WEDNESDAY NIGHT...THOUGH THIS WAVE DAMPENS SIGNIFICANTLY
AS IT MOVES INTO THE UPPER RIDGE ACROSS THE MIDWEST. MODEL FORECAST
SOUNDINGS AND TIME-HEIGHT PLOTS INDICATE INCREASING MID-HIGH LEVEL
MOISTURE MAINLY AFTER MIDNIGHT WEDNESDAY NIGHT ACROSS OUR SOUTHWEST.
GUIDANCE (NAM...GFS...ECMWF AND SREF) DOES PRODUCE SOME LIGHT QPF
ACROSS CENTRAL ILLINOIS THURSDAY AS THIS WAVE CONTINUES TO
DEAMPLIFY...THOUGH FORECAST SOUNDINGS INDICATE LOW LEVELS INITIALLY
DRY AND SATURATION APPEARS INCOMPLETE MAKING PRECIP AT THE SURFACE A
LOW PROBABILITY. WEAKENING SURFACE HIGH PRESSURE RIDGE EVENTUALLY
MOVES INTO THE AREA THURSDAY NIGHT AND FRIDAY...ROUNDING OUT A FEW
DAYS OF MAINLY DRY AND SEASONABLY COOLER DAYS.
RATZER
&&
.LONG TERM...
313 PM CST
SATURDAY THROUGH TUESDAY...
ATTENTION TURNS TO A PAIR OF APPROACHING SHORT WAVE TROUGHS IN A
SOMEWHAT SPLIT FLOW REGIME. GUIDANCE HAS TRENDED WEAKER WITH THE
SOUTHERN STREAM DISTURBANCE...WHICH MOVES OUT ACROSS THE SOUTHERN
PLAINS AND GULF COAST STATES THROUGH SATURDAY. DECENT AGREEMENT IN
MODEL SOLUTIONS OF A MORE DIGGING NORTHERN STREAM WAVE COMING OUT OF
THE NORTHERN ROCKIES FRIDAY AND MOVING INTO THE LOWER MISSOURI AND
LOWER OHIO VALLEYS ON SATURDAY. WHILE MAIN SURFACE LOW PRESSURE
DEVELOPS WITH SOUTHERN SYSTEM ALONG THE GULF COAST...NORTHERN STREAM
FORCING DOES INDUCE AN INVERTED TROUGH INTO THE OHIO VALLEY SATURDAY
WHICH CONTINUES TO SUPPORT THE POTENTIAL FOR SOME LIGHT SNOW FROM
SOUTHERN/CENTRAL ILLINOIS INTO NORTHERN INDIANA...POSSIBLY INCLUDING
THE SOUTHEASTERN PART OF OUR CWA AS THE UPPER TROUGH MOVES OVERHEAD.
GUIDANCE STILL FOCUSES GREATER QPF SOUTHEAST OF THE FORECAST AREA...
BUT PRUDENT TO MAINTAIN SLIGHT CHANCES FOR SOME LIGHT ACCUMULATING
SNOW SOUTHEAST OF ABOUT A PONTIAC-VALPARAISO LINE. SURFACE HIGH
PRESSURE RIDGING QUICKLY BUILDS IN BEHIND THIS SYSTEM SATURDAY NIGHT
INTO SUNDAY. TEMPS DO MODERATE TO NORMAL FOR THE WEEKEND...GENERALLY
MID 20S AT NIGHT TO LOW/MID 30S BY DAY.
12Z GFS AND ECMWF RUNS HAVE COME INTO GOOD AGREEMENT IN BRINGING A
MORE AMPLIFIED UPPER TROUGH INTO THE CENTRAL CONUS SUNDAY NIGHT
THROUGH TUESDAY...WITH A STRONGER EMBEDDED SHORT WAVE MOVING ACROSS
THE UPPER MIDWEST LATE MONDAY-TUESDAY WITH DEEPENING LOW PRESSURE
PASSING TO OUR NORTH. THIS RESULTS IN WARMING TEMPERATURES ON
STRENGTHENING SOUTH WINDS...WITH THE POTENTIAL OF RAIN/SNOW CHANGING
TO RAIN BY LATE MONDAY AND CONTINUING TUESDAY AHEAD OF THE
APPROACHING COLD FRONT AS THE LOW MOVES ACROSS THE NORTHERN LAKES.
SOME DETAIL AND SPEED DIFFERENCES DO EXIST BETWEEN MODELS AND MUCH
COULD CHANGE BETWEEN NOW AND MONDAY...THOUGH IT DOES APPEAR THAT
COLDER AIR WOULD SPREAD INTO THE REGION LATER TUESDAY/TUESDAY NIGHT
WITH PRECIPITATION TAPERING OFF AS IT MIXES/CHANGES TO LIGHT SNOW.
COLDER AIR WOULD THEN ARRIVE IN TIME FOR THE CHRISTMAS HOLIDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* MVFR CEILINGS THROUGH MUCH OF THE FORECAST PERIOD.
* LINGERING SHOWERS EXITING THIS AFTERNOON.
* STRONG WEST/NORTHWEST WINDS THIS AFTERNOON.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
SURFACE LOW AND FRONTAL BOUNDARY CONTINUE TO PUSH THROUGH THE
REGION EARLY THIS AFTERNOON...WITH CEILINGS AND SHOWERS STILL
LINGERING ACROSS THE TERMINALS AND WHILE WEST NORTHWEST WINDS
BEGIN TO INCREASE. EXPECT ANY LINGERING PRECIP TO EXIT OVER THE
NEXT SEVERAL HOURS WHILE CURRENT LOW END MVFR CEILINGS OBSERVE A
SLOW RISING TREND THIS AFTERNOON. DID KEEP MVFR CEILINGS IN
THROUGH TOMORROW AS A FAIR AMOUNT OF STRATUS DOES REMAIN UPSTREAM.
THE CURRENT HOLES DEVELOPING ON THE WESTERN EDGE COULD BE A
PREVAILING FEATURE ON WEDNESDAY...POSSIBLY REACHING THE TERMINALS
WEDNESDAY AFTERNOON. POST FRONTAL WEST NORTHWEST WINDS ARE
INCREASING EARLY THIS AFTERNOON AND EXPECT THIS INCREASE TO
CONTINUE...WITH GUSTS LIKELY PERSISTING OVERNIGHT INTO WEDNESDAY
MORNING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE WITH MVFR CEILINGS TODAY AND TONIGHT...MEDIUM
CONFIDENCE OF DURATION ON WEDNESDAY.
* HIGH CONFIDENCE WITH SHOWER TRENDS.
* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT THROUGH MONDAY...DRY/VFR.
&&
.MARINE...
130 PM CST
LOW PRESSURE AND A COLD FRONT HAVE PASSES EAST OF LAKE MICHIGAN AND
WINDS HAVE SHIFTED NORTHWESTERLY. STRONG COLD ADVECTION AND STRONG
PRESSURE RISES AS THE LOW PULLS AWAY TO THE EAST AND HIGH PRESSURE
BUILDS ACROSS THE NORTHERN PLAINS WILL COMBINE TO DRIVE WINDS TO
30KT FOR THE REMAINDER OF THE AFTERNOON THROUGH TONIGHT AND MUCH OF
TOMORROW. THERE IS THE POTENTIAL FOR A FEW GALE FORCE GUSTS...BUT
IN GENERAL...DO NOT EXPECT ENOUGH PREVAILING GALE FORCE WINDS TO
NECESSITATE A GALE WARNING. HOWEVER...A SMALL CRAFT ADVISORY HAS
ALREADY BEEN ISSUED FOR THE NEARSHORE WATERS AND EXPECT THAT TO PLAY
OUT AS CURRENTLY ADVERTISED. THE OVERALL PATTERN WILL BE SLOWLY
PROGRESSIVE...SO BRISK WINDS WILL REMAIN OVER THE LAKE THROUGH
THURSDAY...BUT AS HIGH PRESSURE BEGINS TO BUILD ACROSS THE WESTERN
GREAT LAKES...WINDS SHOULD DROP OFF AND BECOME MORE VARIABLE IN
DIRECTION. HIGH PRESSURE WILL PREVAIL ACROSS THE GREAT LAKES FROM
LATE THURSDAY THROUGH THE WEEKEND...KEEPING WINDS RELATIVELY LIGHT
IN SPEED AND VARIABLE IN DIRECTION. BY EARLY NEXT WEEK...THE HIGH
SHOULD FINALLY PUSH EAST OF LAKE MICHIGAN AS LOW PRESSURE BEGINS TO
DEVELOP OVER THE NORTHERN PLAINS. THIS SHOULD SET UP A PERIOD OF
INCREASING SOUTHERLY WINDS FOR EARLY NEXT WEEK AS A LOW PRESSURE
SYSTEM DEEPENS WHILE CROSSING THE NORTHERN PLAINS AND DRAGGING A
TRAILING COLD FRONT ACROSS THE CENTRAL PLAINS.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 10 AM
WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 10 AM THURSDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
240 PM CST Tue Dec 16 2014
.SHORT TERM...(Tonight)
ISSUED AT 230 PM CST TUE DEC 16 2014
Occluded low pressure system shifts into the eastern Great Lakes
this evening, allowing the gradient to gradually relax and decrease
wind gusts. Latest NAM forecast soundings and HRRR ceiling guidance
suggest lower clouds will persist overnight, and given deep cyclonic
flow and in-building subsidence inversion at 900 MB, believe this
will hold true. Therefore have increased cloud cover overnight.
Lows will be challenging with the full effect of CAA being offset by
insulating effects of cloud cover. Have trended mins 2-3 degrees
warmer than MET/MAV blend, which gives lower 20s west of the IL
River, to mid 20s central/east.
&&
.LONG TERM...(Wednesday through Tuesday)
ISSUED AT 230 PM CST TUE DEC 16 2014
High pressure to settle into the region on Wednesday bringing in dry
with more seasonal temperatures. Forecast soundings...although not
as aggressive as yesterday with the low level moisture...continues
to indicate moisture trapped beneath a subsidence inversion will
keep a bit more cloudiness around the area during the day. Soundings
do show some breaks developing by late morning into the afternoon
hours but just in time to see mid and high level moisture/clouds
stream in ahead of our next weather system for Thursday. That weather
system is expected to spread light snow into parts of extreme west
central through southeast Illinois Thursday morning. Model runs had
been suggesting as the precip spread northeast into a more confluent
flow pattern over the lower Great Lakes coverage would decrease
during the day Thursday. Most of the operational models have backed
off that idea for now and have brought some light precip further north
and east into our area on Thursday so have brought precip chances further
north into the forecast area. Snowfall could accumulate up to 1 inch
from Springfield south Thursday morning before the area begins to
decrease in coverage during the afternoon.
Thursday`s system should be off to our east by evening with our attention
turning to a more significant wave over eastern Texas that will push
a surface low east-northeast across the Gulf Coast states Friday. The
northern periphery of the precip associated with the southern wave will
track over southeast Illinois with once again light snowfall for later
Friday night into Saturday. Current indications suggest an inch or less
for southeast Illinois. High pressure will then shift east into our
area for Sunday into early Monday bringing quiet weather to the region.
Quite a bit of model spread with respect to the system for early next
week, which will be moving southeast out of the Northern Plains and
tracking a strong low pressure system at the surface to our north
Monday. The operational GFS is more progressive with the early week
system and sweeps the cold front thru our area Tuesday afternoon and
evening with little if any southern stream interaction showing up
on the latest model run. In contrast, the latest ECMWF was indicating
a more phased look between the northern and southern streams which
effectively holds up the front pushing across our area later Tuesday
until a surface wave shifts off to our northeast Tuesday night.
This would bring rain on Tuesday, which would eventually change to
snow later in the day and evening as the deepening surface wave shifts
away from our area by Wednesday.
Seems as if each model run has a different solution with respect to
the pattern over the Midwest the first half of next week so not making
any significant changes to the grids at this point for days 7 and 8.
After our brief warm up ahead of the system on Monday and Tuesday, it
turns colder again by midweek.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1138 AM CST TUE DEC 16 2014
Remnant showers and drizzle with visibility reductions to 2-4 SM will
exit the eastern TAF sites by 20Z. Ceilings have already risen to
MVFR levels at PIA/SPI, and this trend will continue to the east
this afternoon, as low pressure shifts farther away from the
region. Main concern for this forecast is possibility/extent of
scattering out MVFR ceilings tonight into tomorrow morning.
Forecast soundings from higher resolution models point to a
familiar scene from the past few weeks, with a strong subsidence
inversion trapping moisture around 1500 FT. This looks likely to
keep ceilings in place at least through 15Z/Wed, even with
northwest winds bringing in drier air at the surface. Tight
pressure gradient will keep west winds gusting at 25 kts this
afternoon. Gusts will diminish after sunset with speeds tapering
to around 10 kts as the gradient relaxes, and under 10 kts towards
sunrise as surface ridge builds in from the NW.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...25
LONG TERM...Smith
AVIATION...25
AREA FORECAST DISCUSSION
NWS DES MOINES IA
535 PM CST WED DEC 17 2014
.SHORT TERM /TONIGHT/...
ISSUED AT 245 PM CST WED DEC 17 2014
A QUIET AFTERNOON IS IN STORE FOR THE CWA WITH SURFACE HIGH PRESSURE
ANCHORED ALONG THE MISSOURI RIVER VALLEY. A SHARP 300 MB SHORTWAVE
TROUGH CURRENTLY EJECTING FROM THE FOUR CORNERS REGION WILL ENTER
SOUTHWEST IOWA BY 12Z THURSDAY. NAM/GFS ARE TOO SLOW WITH RETURNING
MID-LEVEL MOISTURE (MANIFESTING ITSELF AS AN ALTOSTRATUS DECK) NOW
WELL INTO SW IOWA AS WELL AS WITH PRECIP COVERAGE WITH THIS SYSTEM
IN OKLAHOMA. THE HRRR BEST REFLECTS REALITY IN TERMS OF PRECIP
COVERAGE BUT IS ABOUT 3 HOURS BEHIND THE CURVE WITH CLOUD PLACEMENT.
HAVE SUBSEQUENTLY MANUALLY INCREASED CLOUD COVER OVER THE SW HALF OF
THE CWA AND USED THE HRRR FOR TIMING THE ONSET OF SNOW IN THE
SOUTHWESTERN CWA. LOW TEMPERATURES TONIGHT...ESPECIALLY OVER THE
NORTH...WILL BE DEPENDENT ON HOW QUICKLY CLOUDS CAN ADVECT OVERHEAD.
THESE WILL NEED TO BE MONITORED THIS EVENING AND ADJUSTED UPWARD
SHOULD THE CLOUDS ADVANCE FASTER THAN CURRENTLY FORECAST.
THE FASTER MOISTURE RETURN THROWS JUST ANOTHER WRENCH IN TIMING AND
AMOUNTS OF SNOWFALL IN SOUTHERN IOWA LATE TONIGHT. 12/18Z MODEL BUFR
SOUNDINGS DEPICT A STOUT 925-850MB DRY WEDGE ATTENDANT WITH THE
SURFACE RIDGE...BUT THIS MIDLEVEL MOISTURE MAY SATURATE THE COLUMN
FASTER THAN PROGGED AND LEAD TO HIGHER SNOWFALL TOTALS. OVERALL MADE
LITTLE CHANGES TO THE FORECAST IN THIS RESPECT...BUT DID TIGHTEN THE
POP GRADIENT AS IT ADVANCES NORTHEAST FROM 09 TO 12Z THINKING THAT
THE LOW LEVEL DRY AIR WILL RESULT IN A SHARP CUTOFF IN ACCUMULATING
SNOW.
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
ISSUED AT 245 PM CST WED DEC 17 2014
A FEW CHALLENGES OVER THE EXTENDED PERIOD...WITH A NUMBER OF WEAK
SYSTEMS TO AFFECT PORTIONS OF THE AREA THROUGH THE PERIOD. SPLIT
FLOW CONTINUES TO BE THE MAIN DRIVING FORCE BEHIND THE RATHER
QUIESCENT WEATHER FOR MID DECEMBER. RATHER HIGH AMPLITUDE RIDGE OF
HIGH PRESSURE STILL ANCHORED FROM THE NORTHERN PLAINS TO THE GULF
COAST NEXT FEW DAYS. FIRST WAVE CURRENTLY OVER THE SOUTHERN
PLAINS TODAY AND SHOULD MOVE NORTHEAST THROUGH THU MORNING. AHEAD
OF THE WEAK SYSTEM WARM AIR ADVECTION AND LIMITED MOISTURE WILL BE
FORCED UPWARD IN AN AREA OF ISENTROPIC LIFT OVER SOUTHERN IOWA
THURSDAY. THE LIFT AND MOISTURE WILL BE ATTEMPTING TO OVERCOME THE
DRY AIRMASS CURRENTLY IN PLACE...LIMITING OVERALL AMOUNTS. THIS
WILL RESULT IN SOME RATHER LIGHT SNOW DURING THE MORNING HOURS
WITH MINOR ACCUMULATIONS GENERALLY LESS THAN AN INCH. DURING THE
EARLY AFTERNOON HOURS...BUFR SOUNDINGS SHOW THAT WE LOSE ICE
INTRODUCTION ACROSS THE SOUTHWEST AND SOUTH. HAVE INTRODUCED SOME
PATCHY FREEZING DRIZZLE ALONG WITH VERY LIGHT SNOW DURING THE
AFTERNOON HOURS...THOUGH EXPECTATIONS ARE THAT ANY PRECIPITATION
BY THAT TIME WILL BE VERY LIGHT AND LITTLE IF ANY ICE ACCUMULATION
IS EXPECTED. NEXT SYSTEM ARRIVES BY SUNDAY AND MONDAY AND EXTENDS
INTO TUESDAY. LOWER CONFIDENCE MOVING FORWARD WITH A CONSENSUS
SOLUTION AS THE GFS IS QUITE MILD WHILE THE EURO IS NOW SUGGESTING
A SOLUTION WITH MORE SIGNIFICANT DYNAMIC COOLING AS THE PRECIP
ARRIVES INTO MONDAY. THE EURO SUGGESTS MORE SNOW THAN RAIN/SNOW
MIX. GIVEN THE EVENT IS STILL 5 DAYS AWAY...WILL HOLD ONTO CURRENT
MIX TRENDS FOR NOW...AND MONITOR DURING SUBSEQUENT MODEL PACKAGES.
THE ONE TREND THAT IS BEGINNING TO EMERGE IS COLDER AIR AS NEXT
WEEK PROGRESSES. AS A STRONG PACNW STREAM WAVE ADVANCES EAST INTO
THE WESTERN STATES...MIDWEST RIDGE FINALLY BEGINS TO BREAK DOWN
AND BECOME DISPLACED BY A LONG WAVE TROUGH. THIS SHOULD SPELL A
TRANSITION TO A MORE ACTIVE AND COLDER PATTERN TOWARD THE END OF
THE EXTENDED. AS THE WAVE TUESDAY DEEPENS...A RATHER STRONG SFC
WAVE WILL EJECT NORTH NORTHEAST OUT OF EASTERN TEXAS TO EASTERN
MICHIGAN WEDNESDAY. GIVEN THE CURRENT GFS/EURO PACKAGES...THE MAIN
H850 MOISTURE PLUME...BETTER FORCING...AND HIGHER PRECIPITATION
AMOUNTS WILL PROBABLY END UP EAST OF THE REGION. WILL MONITOR FOR
GENERAL WESTWARD DRIFT NEXT SEVERAL PACKAGES...THIS SOMETIMES
OCCURS WITH WINTER STORM EVOLUTION IN MODEL PACKAGES...FIRST
PROJECTING THE EVENT TOO FAR EAST THEN PULLING IT BACK AS THE
EVENT NEARS.
&&
.AVIATION...18/00Z
ISSUED AT 520 PM CST WED DEC 17 2014
SYSTEM IN PLAINS WILL CONTINUE TO LIFT NORTHEAST AND WEAKEN
TONIGHT INTO THURSDAY. INITIALLY...VFR CEILINGS WILL SPREAD ACROSS
IOWA TONIGHT BUT WITH DRY LOW LEVELS...CLOUDS WILL REMAIN MID TO
HIGH LEVEL. DEEPER SATURATION OCCURS NEAR THE MISSOURI BORDER AND
SOME MVFR CEILINGS WITH LIGHT SNOW WILL BE POSSIBLE NEAR THE
MISSOURI BORDER BY DAYBREAK ON THURSDAY. HOWEVER...MUCH OF THE
FORECAST AREA WILL REMAIN WITH VFR CONDITIONS THROUGH THURSDAY
WITH THE POSSIBLE EXCEPTION OF KOTM. SURFACE WINDS WILL REMAIN
GENERALLY LIGHT AND VARIABLE FOR THE DURATION OF THE FORECAST.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SKOW
LONG TERM...REV
AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS DES MOINES IA
330 PM CST TUE DEC 16 2014
.SHORT TERM /TONIGHT/...
ISSUED AT 330 PM CST TUE DEC 16 2014
MAIN CHALLENGES TONIGHT WILL BE CLOUD COVER AND TEMPERATURES.
BRIEF BREAK IN CLOUDS THIS AFTERNOON WEST AS NOSE OF COLD AIR
ADVECTION MOVED SOUTHEAST ACROSS THE REGION. AS THE LOWEST
PORTIONS OF THE BOUNDARY LAYER WARMED...CLOUDS AGAIN FORMED ON THE
TOPS OF THE THERMALS...THEN BACKFILLING TO SOME EXTENT ACROSS THE
REGION. TONIGHT...MAY SEE THE CLOUDS DISSIPATE BRIEFLY AS THE
PROCESS REVERSES WITH SUNSET AND AN AREA OF CLEARING MAY DEVELOP
ONCE AGAIN WEST/CENTRAL. CONFIDENCE ON HOW LONG OR HOW WIDESPREAD
ANY CLEARING WILL BE IS LOW...GIVEN THE TENDENCY FOR MORE STRATUS
TO REDEVELOP AS THE RIDGE WEST OF THE AREA BEGINS TO MOVE EAST
OVERNIGHT. THE OTHER FACTOR REGARDING CLOUD COVER IS A WEAK WAVE
OVER COLORADO THIS AFTERNOON...WHICH IS CAUSING A RETURN OF WARM
AIR ADVECTION OVER THE WESTERN PLAINS. THIS IS GENERATING AN AREA
OF MID LEVEL CLOUDS WHICH SHOULD BEGIN ADVECTING EAST OVER THE
H700 RIDGE TOWARD IOWA OVERNIGHT. CONSEQUENTLY...OVERNIGHT WILL
MOST LIKELY SEE A MIXTURE OF SOME CLEARING EARLY AND CLOUDS MOST
AREAS LATE INTO SUNRISE. WINDS ALOFT WILL CONTINUE TO DECOUPLE BY
EVENING AND LIGHTER NORTHWEST WINDS ARE EXPECTED TONIGHT.
TEMPERATURES WILL BE QUITE CHILLY...AND REGARDLESS OF THE CLOUD
COVER...THE PERSISTENT LOW LEVEL COLD AIR ADVECTION TODAY WILL
RESULT IN OVERNIGHT LOWS NEAR 5 FAR NORTHWEST TO NEAR 20 IN THE
SOUTH. FETCH OF COLD AIR SUGGESTS THE WEST/NORTHWEST WILL BE
COLDER DUE TO ADVECTION TODAY.
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
ISSUED AT 330 PM CST TUE DEC 16 2014
A PROGRESSIVE BUT RELATIVELY CALM WEATHER PATTERN WILL BE IN
PLACE OVER THE REGION THROUGH THE WEEKEND WITH WITH TWO MAIN
WEATHER SYSTEMS OF NOTE ON THURSDAY AND EARLY NEXT WEEK. THE
BEGINNING OF THE PERIOD WILL SEE AN INVERTED 500 MB TROUGH AND
ASSOCIATED PV ANOMALY SWING THROUGH THE UPPER MISSISSIPPI RIVER
VALLEY ON THE BACKSIDE OF A DEPARTING LOW. A SURFACE RIDGE AXIS
WILL ALSO LAY OUT ACROSS THE WESTERN PORTION OF THE STATE ON
WEDNESDAY WITH LIGHT NORTHERLY FLOW OVER THE CWA. THE BIGGEST
QUESTION FOR TOMORROW WILL BE THE EXTENT AND DURATION OF CLOUD
COVER. NAM 0.5-1 KM MOISTURE PROFILES KEEP STRATUS OVER THE
NORTHEAST THROUGH MUCH OF THE DAY TOMORROW AND LEANED TOWARDS THIS
GUIDANCE FOR SKY GRIDS...BUT GIVEN THE UNCERTAINTY IN ANY CLEAR
SLOT POSITIONING HAVE KEPT AT LEAST PARTLY CLOUDY WORDING
THROUGHOUT THE CWA.
LATE WEDNESDAY INTO THURSDAY MORNING WILL SEE A SHARP MID TO
UPPER LEVEL SHORTWAVE SHIFT OFF THE FRONT RANGE AND INTO THE
MISSOURI RIVER VALLEY. THE WAVE WEAKENS AS IT RUNS UP AGAINST THE
DOWNSTREAM RIDGE...BUT PORTIONS OF SOUTHERN IOWA SHOULD SEE
MEASURABLE SNOW THURSDAY MORNING. ALL MEDIUM RANGE SOLUTIONS PLACE
A NARROW BUT STRONG AREA OF DGZ FORCING BETWEEN 09Z AND 18Z ALONG
AND NORTH OF THE MISSOURI BORDER. HOWEVER...NAM SOUNDINGS ARE
NOTABLY DRIER IN THE DGZ COMPARED TO THE GFS AND EC. THE SYSTEM
WILL ALSO BE FIGHTING A WEDGE OF LOW-LEVEL DRY AIR THAT SHOULD
RESULT IN A SHARP PRECIP CUTOFF ALONG THE NORTHERN SIDE OF THE
LINE. FOR THE FORECAST PACKAGE...DID NOT CHANGE COVERAGE TOO MUCH
BUT INCREASED POPS TO HIGH CHANCES OVER THE SOUTH WITH THE
EXPECTATION OF THESE BEING UPPED TO LIKELIES OR CATEGORICAL ONCE
THE LOCATION OF THE GREATEST FORCING AND MOISTURE PROFILES ARE
BETTER RESOLVED. TOTAL SNOWFALL AMOUNTS LOOK TO BE AROUND OR LESS
THAN AN INCH GIVEN THE TRANSIENT NATURE OF THE SYSTEM AND INITAL
SURFACE DRY LAYER.
FRIDAY AND INTO THE WEEKEND LOOK TO REMAIN DRY WITH WEAK SOUTHERLY
FLOW/WAA BRINGING HIGHS BACK ABOVE FREEZING. SATURDAY WILL SEE A
AN UPPER LEVEL TROUGH SWING THROUGH THE REGION...BUT FORECAST
SOUNDINGS REMAIN MOSTLY DRY AND CONFIDENCE WAS NOT HIGH ENOUGH TO
INTRODUCE POPS IN ANY GIVEN LOCATION. A FEW LIGHT SNOW SHOWERS ARE
CERTAINLY NOT OUT OF THE REALM OF POSSIBILITIES WITH THE PASSAGE
OF THIS SYSTEM.
HOWEVER...THE WEATHER PATTERN TAKES A MORE ACTIVE TURN EARLY NEXT
WEEK AS A LONGWAVE TROUGH DIGS OVER THE ROCKIES AND SLOWLY
MIGRATES EAST TOWARDS THE CWA BY THE END OF THE PERIOD. THE GFS
AND EC ARE IN SOMEWHAT GOOD AGREEMENT WITH THE RESULTANT SURFACE
CYCLONE AND TAKE IT ON A COURSE NORTH OF THE CWA...WITH IOWA
REMAINING IN THE WARM SECTOR AND SEEING A MIX OF RAIN AND SNOW
ALONG THE ATTENDANT WARM/COLD FRONTAL BOUNDARIES.
&&
.AVIATION...16/18Z
ISSUED AT 1140 AM CST TUE DEC 16 2014
RATHER LOW CONFIDENCE FORECAST CONCERNING STRATUS. AT THE
MOMENT...PARTIAL CLEARING HAS DEVELOPED OVER WESTERN/CENTRAL
SECTIONS IN PATH OF STRONGEST COLD AIR ADVECTION. HRRR SHOWS THE
AREA EXPANDING A BIT THROUGH 01Z OR SO...THEN POSSIBLE BACKFILLING
OVER THE SOUTH AFT 02-03Z. FARTHER WEST...MORE STRATUS CONTINUES
AND ANOTHER WEAK TROUGH OVER MN MAY BRUSH NORTHEAST SECTIONS
THROUGH 02Z KEEPING MVFR CIGS THERE. GIVEN APPROACHING RIDGE
OVERNIGHT...HAVE OPTED TO GENERALLY STICK WITH MVFR CONDITIONS AND
PERSISTENCE. WILL MONITOR FOR POSSIBLE IMPROVEMENTS. /REV
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...REV
LONG TERM...SKOW
AVIATION...REV
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1140 AM CST TUE DEC 16 2014
.UPDATE...
ISSUED AT 607 AM CST TUE DEC 16 2014
THE WIND ADVISORY WILL BE ALLOWED TO EXPIRE AT 12Z. A HANDFUL OF
SITES ARE STILL AT SUSTAINED CRITERIA /26KTS/ BUT A GRADUAL
DOWNWARD TREND IS STILL EXPECTED AS NOTED IN THE SHORT TERM
SECTION BELOW.
&&
.SHORT TERM /TODAY/...
ISSUED AT 335 AM CST TUE DEC 16 2014
IMMEDIATE CONCERNS ARE PRECIP TRENDS AND WIND. PARENT SHORT WAVE
CONTINUES TO MOVE ACROSS IL WITH ONLY MINIMAL UPSTREAM INFLUENCE
FROM DAKOTAS/ONTARIO WAVE. LATEST RAP ANALYSIS SHOWS LITTLE IN THE
WAY OF OMEGA OR FORCING ACROSS FORECAST AREA...JUST SOME TOKEN MID
LEVEL LIFT ASSOCIATED WITH DAKOTAS/ONTARIO WAVE BARELY GENERATING
LIGHT SNOW/FLURRIES NW AND LOWER BASED H85/H7 OMEGA ALONG THE
DMX/DVN BORDER. NOT ENTIRELY SURE WHAT IS GENERATING THAT OUTSIDE
OF MINOR SEGMENT OF THETA-E ADVECTION DRIVEN MORE BY WRAP AROUND
MOISTURE THAN TEMPS. REGARDLESS...ANY LINGERING UPWARD VERTICAL
MOTION SHOULD WANE OVER THE NEXT SEVERAL HOURS. ANY PRECIP WILL BE
QUITE LIGHT AND TOKEN...BUT WITH TYPE PROBLEMATIC. IR SATELLITE
CLOUD TOP TEMPS AND SOUNDINGS SUGGEST ICE INTRODUCTION WILL VARY
SO FREEZING AND FROZEN HYDROMETEORS ARE BOTH POSSIBLE...AND EVEN
A BRIEF PERIOD OF LIQUID STILL POSSIBLE FAR EAST WITH WARM LAYER
TEMPS STILL 1-3C THERE. NEARLY ALL MODELS ARE UNDERESTIMATING THE
EXTENT OF STRATUS ACROSS THE GREATER MO VALLEY SO HAVE HELD ONTO
CLOUDS FOR MUCH OF THE DAY. LITTLE CONFIDENCE HOW LONG THEY WILL
HOLD ON...BUT CERTAINLY LONGER THAN MODELS SUGGEST.
NO CHANGES TO CURRENT WIND ADVISORY WITH SEVERAL SITES STILL HITTING
SUSTAINED CRITERIA. THEY SHOULD NOT LAST MUCH LONGER HOWEVER WITH
ISALLOBARIC EFFECTS DIMINISHING WITH PRESSURE RISE MAX INTO SERN
IA...AND MAX MSLP GRADIENT EXITING FORECAST AREA. RAP SOUNDINGS
SUGGEST MIXING WILL SUPPORT GUSTS NOT QUITE TO CRITERIA /39KTS/
BUT STILL WELL INTO THE 30S. TEMPS WILL BE FALLING THROUGH MUCH OF
THE DAY. THERE MAY BE A VERY MINOR REBOUND TOWARD MIDDAY BASED ON
RAW TEMP PLUMES...BUT HIGH TEMPS WILL BE AT BEGINNING OF VALID
PERIOD.
.LONG TERM /TONIGHT THROUGH SUNDAY/...
ISSUED AT 335 AM CST TUE DEC 16 2014
THE SYNOPTIC PATTERN HAS FINALLY CHANGED AND WE WILL SEE COOLER
AND SOMEWHAT MORE ACTIVE WEATHER ACROSS CENTRAL IOWA FOR THE NEXT
SEVEN DAYS AND BEYOND. AT 500 MB...A COMPACT LOW PRESSURE CENTER
MOVING OVER MINNESOTA LATER TODAY WILL SLIDE QUICKLY EASTWARD OVER
THE GREAT LAKES TONIGHT AND WEDNESDAY. AT THE SURFACE...THIS
DEPARTURE WILL BE REFLECTED BY A RIDGE OF HIGH PRESSURE BUILDING
DOWN THE DAKOTAS AND INTO IOWA LATE TONIGHT THROUGH
WEDNESDAY...REINFORCING THE COLDER AIR BUT ALSO PROHIBITING
PRECIPITATION ACROSS THE STATE.
MEANWHILE...A LARGE AND BROAD 500 MB TROUGH WILL BUILD OVER THE
ROCKIES AND WESTERN U.S. ON WEDNESDAY...AND EVENTUALLY PROGRESS
EASTWARD AS A SOMEWHAT CONFUSED AREA OF GENERAL TROUGHINESS
PERSISTING FOR THE REST OF THE WORK WEEK. THE SURFACE RIDGE
DISCUSSED EARLIER WILL STUBBORNLY CLING TO MINNESOTA AND MUCH OF
IOWA DURING THIS TIME EVEN AS ATMOSPHERIC MOISTURE ABOVE A VERY
SHALLOW NEAR SURFACE LAYER INCREASES DRAMATICALLY AROUND THURSDAY.
FORECAST SOUNDINGS ARE UNANIMOUS IN ILLUSTRATING THIS MOISTURE
INCREASE COINCIDENT WITH THE ARRIVAL OF THE BROAD 500 MB
TROUGH...HOWEVER...ANY FORCING ASSOCIATED WITH THIS UPPER FEATURE
WILL BE MODEST AT BEST AND THE RESULT WILL LIKELY BE THICK LAYERED
CLOUDS AND SOME FLURRIES OR LIGHT SNOW AT TIMES. HAVE INCLUDED LOW
POPS IN THE 20 TO 30 RANGE FOR SOME OF THIS PERIOD...BUT NO
SIGNIFICANT IMPACTS ARE ANTICIPATED.
A MORE INTERESTING ATMOSPHERIC FEATURE APPEARS IN THE FORM OF A
LONGWAVE BUT INITIALLY SUBTLE 500 MB TROUGH MOVING ASHORE OVER THE
PACIFIC U.S. COAST AROUND SATURDAY. AS THIS TROUGH SUBSEQUENTLY
MOVES EASTWARD OVER THE ROCKIES AND EMERGES OVER THE HIGH PLAINS
AND MIDWEST IT SHOULD INTENSIFY TO SOME EXTENT...THEN BE
REINFORCED BY TRAILING SHORTWAVES AND CARVE OUT A LARGE CENTRAL
U.S. TROUGH EARLY NEXT WEEK. THERE IS OF COURSE A HIGHER DEGREE OF
UNCERTAINTY AT SUCH A LONG RANGE...HOWEVER...IT DOES APPEAR THAT
THERE WILL BE A DECENT CHANCE FOR SOME KIND OF PRECIPITATION
ACROSS IOWA SOMETIME BETWEEN AROUND SUNDAY NIGHT AND TUESDAY OF
NEXT WEEK. EVEN SO...IT REMAINS TO BE SEEN WHETHER TEMPERATURES
WOULD BE MORE SUPPORTIVE OF RAIN OR SNOW FROM THIS SYSTEM. FOR NOW
HAVE ADVERTISED CHANCE POPS EARLY NEXT WEEK AND IT WILL TAKE SOME
TIME BEFORE THERE IS ANY DEGREE OF CONFIDENCE TO RAISE OR
ELIMINATE THEM.
&&
.AVIATION...16/18Z
ISSUED AT 1140 AM CST TUE DEC 16 2014
RATHER LOW CONFIDENCE FORECAST CONCERNING STRATUS. AT THE
MOMENT...PARTIAL CLEARING HAS DEVELOPED OVER WESTERN/CENTRAL
SECTIONS IN PATH OF STRONGEST COLD AIR ADVECTION. HRRR SHOWS THE
AREA EXPANDING A BIT THROUGH 01Z OR SO...THEN POSSIBLE BACKFILLING
OVER THE SOUTH AFT 02-03Z. FARTHER WEST...MORE STRATUS CONTINUES
AND ANOTHER WEAK TROUGH OVER MN MAY BRUSH NORTHEAST SECTIONS
THROUGH 02Z KEEPING MVFR CIGS THERE. GIVEN APPROACHING RIDGE
OVERNIGHT...HAVE OPTED TO GENERALLY STICK WITH MVFR CONDITIONS AND
PERSISTENCE. WILL MONITOR FOR POSSIBLE IMPROVEMENTS. /REV
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SMALL
SHORT TERM...SMALL
LONG TERM...LEE
AVIATION...REV
AREA FORECAST DISCUSSION
NWS DES MOINES IA
607 AM CST TUE DEC 16 2014
.UPDATE...
ISSUED AT 607 AM CST TUE DEC 16 2014
THE WIND ADVISORY WILL BE ALLOWED TO EXPIRE AT 12Z. A HANDFULL OF
SITES ARE STILL AT SUSTAINED CRITERIA /26KTS/ BUT A GRADUAL DOWNWARD
TREND IS STILL EXPECTED AS NOTED IN THE SHORT TERM SECTION BELOW.
&&
.SHORT TERM /TODAY/...
ISSUED AT 335 AM CST TUE DEC 16 2014
IMMEDIATE CONCERNS ARE PRECIP TRENDS AND WIND. PARENT SHORT WAVE
CONTINUES TO MOVE ACROSS IL WITH ONLY MINIMAL UPSTREAM INFLUENCE
FROM DAKOTAS/ONTARIO WAVE. LATEST RAP ANALYSIS SHOWS LITTLE IN THE
WAY OF OMEGA OR FORCING ACROSS FORECAST AREA...JUST SOME TOKEN MID
LEVEL LIFT ASSOCIATED WITH DAKOTAS/ONTARIO WAVE BARELY GENERATING
LIGHT SNOW/FLURRIES NW AND LOWER BASED H85/H7 OMEGA ALONG THE
DMX/DVN BORDER. NOT ENTIRELY SURE WHAT IS GENERATING THAT OUTSIDE
OF MINOR SEGMENT OF THETA-E ADVECTION DRIVEN MORE BY WRAP AROUND
MOISTURE THAN TEMPS. REGARDLESS...ANY LINGERING UPWARD VERTICAL
MOTION SHOULD WANE OVER THE NEXT SEVERAL HOURS. ANY PRECIP WILL BE
QUITE LIGHT AND TOKEN...BUT WITH TYPE PROBLEMATIC. IR SATELLITE
CLOUD TOP TEMPS AND SOUNDINGS SUGGEST ICE INTRODUCTION WILL VARY
SO FREEZING AND FROZEN HYDROMETEORS ARE BOTH POSSIBLE...AND EVEN
A BRIEF PERIOD OF LIQUID STILL POSSIBLE FAR EAST WITH WARM LAYER
TEMPS STILL 1-3C THERE. NEARLY ALL MODELS ARE UNDERESTIMATING THE
EXTENT OF STRATUS ACROSS THE GREATER MO VALLEY SO HAVE HELD ONTO
CLOUDS FOR MUCH OF THE DAY. LITTLE CONFIDENCE HOW LONG THEY WILL
HOLD ON...BUT CERTAINLY LONGER THAN MODELS SUGGEST.
NO CHANGES TO CURRENT WIND ADVISORY WITH SEVERAL SITES STILL HITTING
SUSTAINED CRITERIA. THEY SHOULD NOT LAST MUCH LONGER HOWEVER WITH
ISALLOBARIC EFFECTS DIMINISHING WITH PRESSURE RISE MAX INTO SERN
IA...AND MAX MSLP GRADIENT EXITING FORECAST AREA. RAP SOUNDINGS
SUGGEST MIXING WILL SUPPORT GUSTS NOT QUITE TO CRITERIA /39KTS/
BUT STILL WELL INTO THE 30S. TEMPS WILL BE FALLING THROUGH MUCH OF
THE DAY. THERE MAY BE A VERY MINOR REBOUND TOWARD MIDDAY BASED ON
RAW TEMP PLUMES...BUT HIGH TEMPS WILL BE AT BEGINNING OF VALID
PERIOD.
.LONG TERM /TONIGHT THROUGH SUNDAY/...
ISSUED AT 335 AM CST TUE DEC 16 2014
THE SYNOPTIC PATTERN HAS FINALLY CHANGED AND WE WILL SEE COOLER
AND SOMEWHAT MORE ACTIVE WEATHER ACROSS CENTRAL IOWA FOR THE NEXT
SEVEN DAYS AND BEYOND. AT 500 MB...A COMPACT LOW PRESSURE CENTER
MOVING OVER MINNESOTA LATER TODAY WILL SLIDE QUICKLY EASTWARD OVER
THE GREAT LAKES TONIGHT AND WEDNESDAY. AT THE SURFACE...THIS
DEPARTURE WILL BE REFLECTED BY A RIDGE OF HIGH PRESSURE BUILDING
DOWN THE DAKOTAS AND INTO IOWA LATE TONIGHT THROUGH
WEDNESDAY...REINFORCING THE COLDER AIR BUT ALSO PROHIBITING
PRECIPITATION ACROSS THE STATE.
MEANWHILE...A LARGE AND BROAD 500 MB TROUGH WILL BUILD OVER THE
ROCKIES AND WESTERN U.S. ON WEDNESDAY...AND EVENTUALLY PROGRESS
EASTWARD AS A SOMEWHAT CONFUSED AREA OF GENERAL TROUGHINESS
PERSISTING FOR THE REST OF THE WORK WEEK. THE SURFACE RIDGE
DISCUSSED EARLIER WILL STUBBORNLY CLING TO MINNESOTA AND MUCH OF
IOWA DURING THIS TIME EVEN AS ATMOSPHERIC MOISTURE ABOVE A VERY
SHALLOW NEAR SURFACE LAYER INCREASES DRAMATICALLY AROUND THURSDAY.
FORECAST SOUNDINGS ARE UNANIMOUS IN ILLUSTRATING THIS MOISTURE
INCREASE COINCIDENT WITH THE ARRIVAL OF THE BROAD 500 MB
TROUGH...HOWEVER...ANY FORCING ASSOCIATED WITH THIS UPPER FEATURE
WILL BE MODEST AT BEST AND THE RESULT WILL LIKELY BE THICK LAYERED
CLOUDS AND SOME FLURRIES OR LIGHT SNOW AT TIMES. HAVE INCLUDED LOW
POPS IN THE 20 TO 30 RANGE FOR SOME OF THIS PERIOD...BUT NO
SIGNIFICANT IMPACTS ARE ANTICIPATED.
A MORE INTERESTING ATMOSPHERIC FEATURE APPEARS IN THE FORM OF A
LONGWAVE BUT INITIALLY SUBTLE 500 MB TROUGH MOVING ASHORE OVER THE
PACIFIC U.S. COAST AROUND SATURDAY. AS THIS TROUGH SUBSEQUENTLY
MOVES EASTWARD OVER THE ROCKIES AND EMERGES OVER THE HIGH PLAINS
AND MIDWEST IT SHOULD INTENSIFY TO SOME EXTENT...THEN BE
REINFORCED BY TRAILING SHORTWAVES AND CARVE OUT A LARGE CENTRAL
U.S. TROUGH EARLY NEXT WEEK. THERE IS OF COURSE A HIGHER DEGREE OF
UNCERTAINTY AT SUCH A LONG RANGE...HOWEVER...IT DOES APPEAR THAT
THERE WILL BE A DECENT CHANCE FOR SOME KIND OF PRECIPITATION
ACROSS IOWA SOMETIME BETWEEN AROUND SUNDAY NIGHT AND TUESDAY OF
NEXT WEEK. EVEN SO...IT REMAINS TO BE SEEN WHETHER TEMPERATURES
WOULD BE MORE SUPPORTIVE OF RAIN OR SNOW FROM THIS SYSTEM. FOR NOW
HAVE ADVERTISED CHANCE POPS EARLY NEXT WEEK AND IT WILL TAKE SOME
TIME BEFORE THERE IS ANY DEGREE OF CONFIDENCE TO RAISE OR
ELIMINATE THEM.
&&
.AVIATION...16/12Z
ISSUED AT 607 AM CST TUE DEC 16 2014
PRIMARY CONCERN THROUGH THE PERIOD WILL BE CLOUD TRENDS.
WIDESPREAD MVFR CIGS...WITH ISOLATED IFR...EXTEND FROM IA
UPSTREAM INTO NE...SD AND MN. VIS/FOG SATELLITE IMAGERY DOES NOTE
A SLIVER OR TWO OF CLEARING OVER THE ERN DAKOTAS...BUT OVERALL
TRENDS APPEAR TO FAVOR CONTINUED MVFR CIGS. MODELS HAVE NOT BEEN
HANDLING LOW CLOUD TREND WELL...UNDERREPRESENTED...SO ESSENTIALLY
STAYED WITH PERSISTENCE AT TAF SITES UNTIL TRENDS SUGGEST
OTHERWISE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...SMALL
SHORT TERM...SMALL
LONG TERM...LEE
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS DES MOINES IA
336 AM CST TUE DEC 16 2014
.SHORT TERM /TODAY/...
ISSUED AT 335 AM CST TUE DEC 16 2014
IMMEDIATE CONCERNS ARE PRECIP TRENDS AND WIND. PARENT SHORT WAVE
CONTINUES TO MOVE ACROSS IL WITH ONLY MINIMAL UPSTREAM INFLUENCE
FROM DAKOTAS/ONTARIO WAVE. LATEST RAP ANALYSIS SHOWS LITTLE IN THE
WAY OF OMEGA OR FORCING ACROSS FORECAST AREA...JUST SOME TOKEN MID
LEVEL LIFT ASSOCIATED WITH DAKOTAS/ONTARIO WAVE BARELY GENERATING
LIGHT SNOW/FLURRIES NW AND LOWER BASED H85/H7 OMEGA ALONG THE
DMX/DVN BORDER. NOT ENTIRELY SURE WHAT IS GENERATING THAT OUTSIDE
OF MINOR SEGMENT OF THETA-E ADVECTION DRIVEN MORE BY WRAP AROUND
MOISTURE THAN TEMPS. REGARDLESS...ANY LINGERING UPWARD VERTICAL
MOTION SHOULD WANE OVER THE NEXT SEVERAL HOURS. ANY PRECIP WILL BE
QUITE LIGHT AND TOKEN...BUT WITH TYPE PROBLEMATIC. IR SATELLITE
CLOUD TOP TEMPS AND SOUNDINGS SUGGEST ICE INTRODUCTION WILL VARY
SO FREEZING AND FROZEN HYDROMETEORS ARE BOTH POSSIBLE...AND EVEN
A BRIEF PERIOD OF LIQUID STILL POSSIBLE FAR EAST WITH WARM LAYER
TEMPS STILL 1-3C THERE. NEARLY ALL MODELS ARE UNDERESTIMATING THE
EXTENT OF STRATUS ACROSS THE GREATER MO VALLEY SO HAVE HELD ONTO
CLOUDS FOR MUCH OF THE DAY. LITTLE CONFIDENCE HOW LONG THEY WILL
HOLD ON...BUT CERTAINLY LONGER THAN MODELS SUGGEST.
NO CHANGES TO CURRENT WIND ADVISORY WITH SEVERAL SITES STILL HITTING
SUSTAINED CRITERIA. THEY SHOULD NOT LAST MUCH LONGER HOWEVER WITH
ISALLOBARIC EFFECTS DIMINISHING WITH PRESSURE RISE MAX INTO SERN
IA...AND MAX MSLP GRADIENT EXITING FORECAST AREA. RAP SOUNDINGS
SUGGEST MIXING WILL SUPPORT GUSTS NOT QUITE TO CRITERIA /39KTS/
BUT STILL WELL INTO THE 30S. TEMPS WILL BE FALLING THROUGH MUCH OF
THE DAY. THERE MAY BE A VERY MINOR REBOUND TOWARD MIDDAY BASED ON
RAW TEMP PLUMES...BUT HIGH TEMPS WILL BE AT BEGINNING OF VALID
PERIOD.
.LONG TERM /TONIGHT THROUGH SUNDAY/...
ISSUED AT 335 AM CST TUE DEC 16 2014
THE SYNOPTIC PATTERN HAS FINALLY CHANGED AND WE WILL SEE COOLER
AND SOMEWHAT MORE ACTIVE WEATHER ACROSS CENTRAL IOWA FOR THE NEXT
SEVEN DAYS AND BEYOND. AT 500 MB...A COMPACT LOW PRESSURE CENTER
MOVING OVER MINNESOTA LATER TODAY WILL SLIDE QUICKLY EASTWARD OVER
THE GREAT LAKES TONIGHT AND WEDNESDAY. AT THE SURFACE...THIS
DEPARTURE WILL BE REFLECTED BY A RIDGE OF HIGH PRESSURE BUILDING
DOWN THE DAKOTAS AND INTO IOWA LATE TONIGHT THROUGH
WEDNESDAY...REINFORCING THE COLDER AIR BUT ALSO PROHIBITING
PRECIPITATION ACROSS THE STATE.
MEANWHILE...A LARGE AND BROAD 500 MB TROUGH WILL BUILD OVER THE
ROCKIES AND WESTERN U.S. ON WEDNESDAY...AND EVENTUALLY PROGRESS
EASTWARD AS A SOMEWHAT CONFUSED AREA OF GENERAL TROUGHINESS
PERSISTING FOR THE REST OF THE WORK WEEK. THE SURFACE RIDGE
DISCUSSED EARLIER WILL STUBBORNLY CLING TO MINNESOTA AND MUCH OF
IOWA DURING THIS TIME EVEN AS ATMOSPHERIC MOISTURE ABOVE A VERY
SHALLOW NEAR SURFACE LAYER INCREASES DRAMATICALLY AROUND THURSDAY.
FORECAST SOUNDINGS ARE UNANIMOUS IN ILLUSTRATING THIS MOISTURE
INCREASE COINCIDENT WITH THE ARRIVAL OF THE BROAD 500 MB
TROUGH...HOWEVER...ANY FORCING ASSOCIATED WITH THIS UPPER FEATURE
WILL BE MODEST AT BEST AND THE RESULT WILL LIKELY BE THICK LAYERED
CLOUDS AND SOME FLURRIES OR LIGHT SNOW AT TIMES. HAVE INCLUDED LOW
POPS IN THE 20 TO 30 RANGE FOR SOME OF THIS PERIOD...BUT NO
SIGNIFICANT IMPACTS ARE ANTICIPATED.
A MORE INTERESTING ATMOSPHERIC FEATURE APPEARS IN THE FORM OF A
LONGWAVE BUT INITIALLY SUBTLE 500 MB TROUGH MOVING ASHORE OVER THE
PACIFIC U.S. COAST AROUND SATURDAY. AS THIS TROUGH SUBSEQUENTLY
MOVES EASTWARD OVER THE ROCKIES AND EMERGES OVER THE HIGH PLAINS
AND MIDWEST IT SHOULD INTENSIFY TO SOME EXTENT...THEN BE
REINFORCED BY TRAILING SHORTWAVES AND CARVE OUT A LARGE CENTRAL
U.S. TROUGH EARLY NEXT WEEK. THERE IS OF COURSE A HIGHER DEGREE OF
UNCERTAINTY AT SUCH A LONG RANGE...HOWEVER...IT DOES APPEAR THAT
THERE WILL BE A DECENT CHANCE FOR SOME KIND OF PRECIPITATION
ACROSS IOWA SOMETIME BETWEEN AROUND SUNDAY NIGHT AND TUESDAY OF
NEXT WEEK. EVEN SO...IT REMAINS TO BE SEEN WHETHER TEMPERATURES
WOULD BE MORE SUPPORTIVE OF RAIN OR SNOW FROM THIS SYSTEM. FOR NOW
HAVE ADVERTISED CHANCE POPS EARLY NEXT WEEK AND IT WILL TAKE SOME
TIME BEFORE THERE IS ANY DEGREE OF CONFIDENCE TO RAISE OR
ELIMINATE THEM.
&&
.AVIATION...16/06Z
ISSUED AT 1136 PM CST MON DEC 15 2014
NORTHWEST WINDS WILL REMAIN GUSTY OVERNIGHT WITH A FEW GUSTS OVER
35 KTS POSSIBLE THROUGH 12Z. RAIN HAS MOVED OVER EASTERN IOWA WITH
SOME WINTRY MIX OVER THE WESTERN PORTION OF THE STATE. MAINLY
NORTHERN SITES WILL HAVE SOME SNOW MIX THOUGH ANY VSBY REDUCTIONS
IN SNOW WILL BE BRIEF. LIFR CIGS ARE BEGINNING TO MOVE EAST.
EXPECT IFR THEN A TRANSITION TO MVFR LATER TONIGHT INTO TUESDAY.
NO CONFIDENCE WHEN THE LARGE STRATUS SHIELD WILL MOVE OUT OF THE
AREA THEREFORE KEPT MVFR STRATUS THROUGH THE PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR AUDUBON-
BOONE-CALHOUN-CARROLL-CERRO GORDO-CRAWFORD-EMMET-FRANKLIN-GREENE-
HAMILTON-HANCOCK-HARDIN-HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-
SAC-STORY-WEBSTER-WINNEBAGO-WORTH-WRIGHT.
&&
$$
SHORT TERM...SMALL
LONG TERM...LEE
AVIATION...DONAVON
AREA FORECAST DISCUSSION
NWS GOODLAND KS
235 AM MST TUE DEC 16 2014
.SHORT TERM...(TODAY THROUGH THURSDAY NIGHT)
ISSUED AT 230 AM MST TUE DEC 16 2014
TODAY-TONIGHT...UPPER RIDGE AXIS MOVES OVER THE AREA FROM THE
SOUTHWEST LATE IN THE DAY ALONG WITH INCREASING MID AND UPPER LEVEL
CLOUDINESS. AS THE RIDGE AXIS SLOWLY MOVES EAST TONIGHT (AHEAD OF
APPROACHING UPPER TROUGH) A BRIEF DECREASE IN CLOUDS EXPECTED
THROUGH MIDNIGHT BEFORE CIRRUS MOVES BACK IN FROM THE SOUTHWEST.
WILL HAVE TO WATCH STRATUS CURRENTLY TO OUR NORTH IN NEBRASKA. NAM
BOUNDARY LAYER RH SUGGESTS THESE CLOUDS WILL MOVE IN THIS LATE
THIS MORNING THROUGH AFTERNOON AS WINDS VEER TO THE EAST. DURING
THE OVERNIGHT HOURS THESE CLOUDS EXPAND TOWARD THE SOUTHWEST.
HIGHS AROUND 30 IN SNOWPACK AREAS OF YUMA AND KIT CARSON COUNTIES
WITH LOW TO MID 30S ALONG AND NORTH OF THE INTERSTATE. TO THE
SOUTH UPPER 30S TO AROUND 40. IF THE STRATUS MOVES IN LIKE THE
LATEST NAM SUGGESTS TEMPERATURES WILL BE A BIT COOLER. LOWS 10-15
IN SNOWPACK AREAS AND ALONG THE NE/KS BORDER WITH MID TEENS TO
AROUND 20 ELSEWHERE.
WEDNESDAY-WEDNESDAY NIGHT...DURING THE DAYLIGHT HOURS MODELS
SHOWING AN INCREASE IN MOISTURE/CLOUDS FROM THE SOUTHWEST
ASSOCIATED WITH A WEATHER DISTURBANCE MOVING TOWARD THE FORECAST
AREA FROM THE SOUTHWEST AHEAD OF MAIN UPPER TROUGH. NAM ALSO
SHOWING STRATUS HOLDING TOUGH OVER MUCH OF THE AREA. THERE IS SOME
WEAK UPPER JET SUPPORT ACROSS THE FAR SOUTHEAST/SOUTHERN PARTS OF
THE AREA LATE IN THE DAY. WILL KEEP SOME SLIGHT CHANCE POPS FOR
LIGHT SNOW ACROSS THE FAR EAST AND NORTHWEST WHERE BETTER 850-500
MOISTURE EXISTS. FOR THE NIGHTTIME PERIOD OUR DAYTIME DISTURBANCE
MOVES NORTHEAST AND OUT OF THE AREA BY MIDNIGHT WITH ANOTHER ON
ITS HEELS...MOVING IN FROM THE SOUTHWEST BY EARLY THURSDAY
MORNING. THERE ALSO APPEARS TO BE A WEST TO EAST MOVEMENT IN THE
850-500MB FLOW. WILL CONTINUE WITH SLIGHT CHANCE/LOW CHANCE POPS
FOR PRIMARILY LIGHT SNOW EAST OF THE CO/KS BORDER. MAY SEE A BRIEF
PERIOD OF ICE PELLETS/SLEET ACROSS THE FAR SOUTHEAST/SOUTH PARTS
OF THE AREA WHERE 900-800MB TEMPERATURES APPROACH -1C TO ZERO.
HIGHS IN THE 20S TO AROUND 30 SNOWPACK AREAS AND LOCATIONS ALONG
THE NE/KS BORDER. FURTHER SOUTH 30S AND POSSIBLY A FEW LOW 40S
(TRIBUNE TO LEOTI). LOWS 10-15 SNOWPACK AREAS WITH TEENS TO MID
20S ELSEWHERE.
THURSDAY-THURSDAY NIGHT...MODELS HAVING DIFFICULTY RESOLVING UPPER
PATTERN BUT GENERAL IDEA IS FOR PRECIPITATION (LIGHT SNOW) ASSOCIATED
WITH WEDNESDAY NIGHTS DISTURBANCE MOVES OUT OF THE AREA AROUND
EARLY TO MID AFTERNOON WITH A LULL IN ACTIVITY BY 00Z FRIDAY AS WE
WATCH ANOTHER DISTURBANCE WITH MAIN UPPER TROUGH APPROACH THE
CONTINENTAL DIVIDE. THIS IS FORECAST TO MOVE OVER THE AREA DURING
THE NIGHT BUT NO PRECIPITATION CURRENTLY EXPECTED. HIGHS IN THE
LOW 30S SNOWPACK AREAS WITH MID TO UPPER 30S ELSEWHERE. LOWS MID
TEENS TO LOW 20S.
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 1249 AM MST TUE DEC 16 2014
MEDIUM RANGE MODELS HAVE COME INTO BETTER AGREEMENT WITH TRACK OF
SYSTEM MOVING ACROSS THE SOUTHERN PLAINS. GIVEN LATEST DATA AND
TRENDS...AM COMFORTABLE WITH REMOVING POPS FROM INITIAL PORTION
OF THE FORECAST PERIOD. CWA WILL REMAIN IN PROGRESSIVE WESTERLY
FLOW ALOFT THROUGH THE WEEKEND WITH FLOW TRANSITIONING TO
NORTHWESTERLY AS TROUGH DEEPENS OVER THE MIDWEST. ECMWF RATHER
AGGRESSIVE WITH BRINGING PRECIP CHANCES TO WESTERN CWA ON MONDAY
NIGHT...ALTHOUGH GFS HAS SIMILAR PATTERN PRECIP DATA MUCH LOWER.
FOR THE TIME BEING GIVE OPERATIONAL DATA AND OVERALL PATTERN THINK
DRY FORECAST IS WARRANTED AT THIS TIME. WILL SEE A SMALL WARM UP
ACROSS THE AREA THROUGH THE WEEKEND WITH TEMPS CLIMBING INTO THE
MID 40S AND SEASONABLE LOW TEMPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1024 PM MST MON DEC 15 2014
CLEARING HAS OCCURRED OVER MOST OF THE AREA WITH THE EXCEPTION OF
KMCK WHERE STRATUS HAS PERSISTED FOR THE LAST FEW HOURS. TIMING
THE DEPARTURE OF THE STATUS IS PROBLEMATIC. THE HRRR CLEARS IT OUT
AT THE START OF THIS FORECAST WHILE THE NAM FORECAST SOUNDING
KEEPS THE STRATUS TILL AFTER 15Z. FOR NOW WILL GO WITH THE NAM
SINCE SATELLITE IMAGES SHOW IT`S PERSISTENT TREND. OTHERWISE KGLD
WILL BE VFR TONIGHT WITH DECREASING NORTHWEST WIND TURNING LIGHT
AND VARIABLE TUESDAY AFTERNOON AS HIGH PRESSURE BUILDS INTO THE
AREA. KMCK WILL ALSO TURN VFR TUESDAY MORNING AND PERHAPS SLIGHTLY
EARLIER.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...99
LONG TERM...JRM
AVIATION...FS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
117 AM MST TUE DEC 16 2014
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 1258 PM MST MON DEC 15 2014
SHORT TERM FORECAST FOCUS IS ON THE WINDY CONDITIONS PRODUCING
AREAS OF BLOWING SNOW ACROSS NORTHEAST COLORADO AND THE
DIMINISHING WINDS OVERNIGHT.
NORTH-NORTHWEST WINDS PICKED UP IN THE STEEP PRESSURE GRADIENT OVER
NORTHEAST COLORADO AS THE SURFACE LOW LIFTS OFF TO THE EAST
NORTHEAST TODAY. WITH SUSTAINED WINDS AROUND 30 AND GUSTS UP TO
40...IT HAS BEEN ENOUGH TO BEGIN MOVING THE WET SNOW RECEIVED SUNDAY
NIGHT ACROSS MAINLY NORTHEAST COLORADO...WHERE THE HIGHEST SNOWFALL
AMOUNT REPORTED IN OUR FORECAST AREA WAS 8" IN YUMA COUNTY. EAST-
WEST ROAD CLOSURES AND ACCIDENTS HAVE BEEN REPORTED OVER NORTHEAST
COLORADO WITH DECREASES IN VISIBILITY TO ONE MILE OR LESS WITH
BLOWING SNOW. ROAD CREWS HAD A PRETTY GOOD HANDLE ON THE ROADS THIS
MORNING BEFORE THE WINDS PICKED UP...BUT HAVE BEEN STRUGGLING TO
KEEP ROADS CLEAR MID-DAY THROUGH EARLY AFTERNOON WITH THE AREAS OF
BLOWING SNOW PRODUCING LOCALIZED SNOW PACKED AND SLICK ROADS. IN
ADDITION TO THE AREAS OF BLOWING SNOW...THERE HAS BEEN A BAND OF
LIGHT SNOW FALLING ACROSS THE NORTHWEST PORTION OF OUR FORECAST
AREA. HAVE KEPT THE LIGHT SNOW AND AREAS OF BLOWING SNOW ACROSS
NORTHEAST COLORADO INTACT FOR THE REMAINDER OF THE AFTERNOON AS A
RESULT WITH SNOW AND BLOWING SNOW EXPECTED TO DIMINISH THIS EVENING.
THE LOW PRESSURE AREA OVER THE EASTERN PLAINS WILL BE LIFTING INTO
THE SOUTHERN GREAT LAKES REGION OVERNIGHT WITH A RIDGE MOVING INTO
PLACE OVER THE CENTRAL HIGH PLAINS ON TUESDAY. HIGH PRESSURE WILL
ALSO BE MOVING INTO THE REGION AT THE SURFACE. THE PRESSURE
GRADIENT WILL DECREASE OVERNIGHT AS THE LOW MOVES FURTHER OFF TO
THE EAST...SO GUSTY AND WINDY CONDITIONS WILL DIMINISH OVERNIGHT
WITH LIGHT WINDS EXPECTED DURING THE DAY ON TUESDAY. THERE WILL
BE SOME CLEARING...BUT TEMPERATURES WILL REMAIN VERY SIMILAR ON
TUESDAY AS THEY WERE TODAY...WITH THE NORTHWEST SECTIONS OF THE
FORECAST AREA LIKELY TO BE AFFECTED FOR AT LEAST THE NEXT COUPLE
OF DAYS BY THE SNOWFALL RECEIVED SUNDAY NIGHT ACROSS PORTIONS OF
NORTHEAST COLORADO.
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 1249 AM MST TUE DEC 16 2014
MEDIUM RANGE MODELS HAVE COME INTO BETTER AGREEMENT WITH TRACK OF
SYSTEM MOVING ACROSS THE SOUTHERN PLAINS. GIVEN LATEST DATA AND
TRENDS...AM COMFORTABLE WITH REMOVING POPS FROM INITIAL PORTION
OF THE FORECAST PERIOD. CWA WILL REMAIN IN PROGRESSIVE WESTERLY
FLOW ALOFT THROUGH THE WEEKEND WITH FLOW TRANSITIONING TO
NORTHWESTERLY AS TROUGH DEEPENS OVER THE MIDWEST. ECMWF RATHER
AGGRESSIVE WITH BRINGING PRECIP CHANCES TO WESTERN CWA ON MONDAY
NIGHT...ALTHOUGH GFS HAS SIMILAR PATTERN PRECIP DATA MUCH LOWER.
FOR THE TIME BEING GIVE OPERATIONAL DATA AND OVERALL PATTERN THINK
DRY FORECAST IS WARRANTED AT THIS TIME. WILL SEE A SMALL WARM UP
ACROSS THE AREA THROUGH THE WEEKEND WITH TEMPS CLIMBING INTO THE
MID 40S AND SEASONABLE LOW TEMPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1024 PM MST MON DEC 15 2014
CLEARING HAS OCCURRED OVER MOST OF THE AREA WITH THE EXCEPTION OF
KMCK WHERE STRATUS HAS PERSISTED FOR THE LAST FEW HOURS. TIMING
THE DEPARTURE OF THE STATUS IS PROBLEMATIC. THE HRRR CLEARS IT OUT
AT THE START OF THIS FORECAST WHILE THE NAM FORECAST SOUNDING
KEEPS THE STRATUS TILL AFTER 15Z. FOR NOW WILL GO WITH THE NAM
SINCE SATELLITE IMAGES SHOW IT`S PERSISTENT TREND. OTHERWISE KGLD
WILL BE VFR TONIGHT WITH DECREASING NORTHWEST WIND TURNING LIGHT
AND VARIABLE TUESDAY AFTERNOON AS HIGH PRESSURE BUILDS INTO THE
AREA. KMCK WILL ALSO TURN VFR TUESDAY MORNING AND PERHAPS SLIGHTLY
EARLIER.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...LOCKHART
LONG TERM...JRM
AVIATION...FS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1030 PM MST MON DEC 15 2014
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 1258 PM MST MON DEC 15 2014
SHORT TERM FORECAST FOCUS IS ON THE WINDY CONDITIONS PRODUCING
AREAS OF BLOWING SNOW ACROSS NORTHEAST COLORADO AND THE
DIMINISHING WINDS OVERNIGHT.
NORTH-NORTHWEST WINDS PICKED UP IN THE STEEP PRESSURE GRADIENT OVER
NORTHEAST COLORADO AS THE SURFACE LOW LIFTS OFF TO THE EAST
NORTHEAST TODAY. WITH SUSTAINED WINDS AROUND 30 AND GUSTS UP TO
40...IT HAS BEEN ENOUGH TO BEGIN MOVING THE WET SNOW RECEIVED SUNDAY
NIGHT ACROSS MAINLY NORTHEAST COLORADO...WHERE THE HIGHEST SNOWFALL
AMOUNT REPORTED IN OUR FORECAST AREA WAS 8" IN YUMA COUNTY. EAST-
WEST ROAD CLOSURES AND ACCIDENTS HAVE BEEN REPORTED OVER NORTHEAST
COLORADO WITH DECREASES IN VISIBILITY TO ONE MILE OR LESS WITH
BLOWING SNOW. ROAD CREWS HAD A PRETTY GOOD HANDLE ON THE ROADS THIS
MORNING BEFORE THE WINDS PICKED UP...BUT HAVE BEEN STRUGGLING TO
KEEP ROADS CLEAR MID-DAY THROUGH EARLY AFTERNOON WITH THE AREAS OF
BLOWING SNOW PRODUCING LOCALIZED SNOW PACKED AND SLICK ROADS. IN
ADDITION TO THE AREAS OF BLOWING SNOW...THERE HAS BEEN A BAND OF
LIGHT SNOW FALLING ACROSS THE NORTHWEST PORTION OF OUR FORECAST
AREA. HAVE KEPT THE LIGHT SNOW AND AREAS OF BLOWING SNOW ACROSS
NORTHEAST COLORADO INTACT FOR THE REMAINDER OF THE AFTERNOON AS A
RESULT WITH SNOW AND BLOWING SNOW EXPECTED TO DIMINISH THIS EVENING.
THE LOW PRESSURE AREA OVER THE EASTERN PLAINS WILL BE LIFTING INTO
THE SOUTHERN GREAT LAKES REGION OVERNIGHT WITH A RIDGE MOVING INTO
PLACE OVER THE CENTRAL HIGH PLAINS ON TUESDAY. HIGH PRESSURE WILL
ALSO BE MOVING INTO THE REGION AT THE SURFACE. THE PRESSURE
GRADIENT WILL DECREASE OVERNIGHT AS THE LOW MOVES FURTHER OFF TO
THE EAST...SO GUSTY AND WINDY CONDITIONS WILL DIMINISH OVERNIGHT
WITH LIGHT WINDS EXPECTED DURING THE DAY ON TUESDAY. THERE WILL
BE SOME CLEARING...BUT TEMPERATURES WILL REMAIN VERY SIMILAR ON
TUESDAY AS THEY WERE TODAY...WITH THE NORTHWEST SECTIONS OF THE
FORECAST AREA LIKELY TO BE AFFECTED FOR AT LEAST THE NEXT COUPLE
OF DAYS BY THE SNOWFALL RECEIVED SUNDAY NIGHT ACROSS PORTIONS OF
NORTHEAST COLORADO.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 229 PM MST MON DEC 15 2014
MAIN CONCERN FOR THIS EXTENDED FORECAST RUN IS PRECIPITATION CHANCES
WEDNESDAY EVENING THROUGH FRIDAY. OVERALL...TEMPERATURES SHOULD BE
NEAR TO BELOW NORMAL THROUGH FRIDAY. BEYOND FRIDAY...A RETURN TO
SLIGHTLY ABOVE NORMAL TEMPERATURES APPEARS MORE LIKELY THAN
YESTERDAYS FORECAST GUIDANCE INDICATED.
FOR TOMORROW NIGHT THROUGH WEDNESDAY AFTERNOON...PRECIPITATION FREE
WEATHER IS ANTICIPATED. BAND OF UPPER LEVEL CLOUD COVER PASSES
THROUGH EARLY TOMORROW NIGHT...FOLLOWED BY SOME BRIEF CLEARING THEN
DENSE CLOUDS MOVING IN AGAIN. SOUTH WINDS RETURN...BRINGING A SLIGHT
INCREASE IN MOISTURE BACK TO THE REGION.
WEDNESDAY NIGHT THROUGH FRIDAY IS THE MAIN PERIOD OF CONCERN. AN
UPPER LEVEL DISTURBANCE SPREADS NORTHEAST INTO THE HIGH PLAINS
WEDNESDAY NIGHT. WITH MOISTURE ADVECTION CONTINUING AND ATMOSPHERIC
LIFT INCREASING...EXPECTING TO SEE DEVELOPMENT OF LIGHT
PRECIPITATION. WHAT MAKES THIS EVENT INTERESTING IS THAT SATURATION
IN THE ICE CRYSTAL GROWTH ZONE IS NOT EXPECTED SOUTH OF A LINE FROM
MCCOOK NEBRASKA TO TRIBUNE KANSAS. WHAT DOES THIS MEAN? THIS MEANS
THAT PRECIPITATION WOULD LIKELY FALL IN THE LIQUID FORM. A SHALLOW
LAYER OF MOISTURE NEAR THE SURFACE HIGHLIGHTS A FREEZING DRIZZLE
THREAT DEVELOPING INSTEAD OF SNOW. FREEZING DRIZZLE WOULD BRING A
LARGER IMPACT TO THE AREA WITH ICE DEVELOPING ON THE ROADWAYS DUE TO
TEMPERATURES IN THE LOW 20S. FOR NOW...PLACED SLIGHT CHANCE TO
CHANCE MENTION OF LIGHT SNOW AND FREEZING DRIZZLE INTO THE FORECAST
SOUTH OF THE PREVIOUSLY MENTIONED LINE. NORTH OF THIS LINE...ICE
GROWTH ZONE SATURATION SEEMS MORE LIKELY SO HAVE MAINTAINED A LIGHT
SNOW MENTION. OVERALL...PRECIPITATION AMOUNTS LOOK QUITE LIGHT SO
ANY SNOW THAT FALLS WILL PRODUCE A MINIMAL IMPACT.
BEYOND FRIDAY...MODEL AGREEMENT IS FAIRLY POOR. EXPECTING A WARMING
TREND INTO THE WEEKEND BUT CHANCES OF PRECIPITATION ARE A BIG
QUESTION MARK. ONE THING TO NOTE IS BOTH THE GFS AND EUROPEAN MODELS
ARE INDICATING ANOTHER POSSIBLE COLD BLAST MONDAY OR TUESDAY OF NEXT
WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1024 PM MST MON DEC 15 2014
CLEARING HAS OCCURRED OVER MOST OF THE AREA WITH THE EXCEPTION OF
KMCK WHERE STRATUS HAS PERSISTED FOR THE LAST FEW HOURS. TIMING
THE DEPARTURE OF THE STATUS IS PROBLEMATIC. THE HRRR CLEARS IT OUT
AT THE START OF THIS FORECAST WHILE THE NAM FORECAST SOUNDING
KEEPS THE STRATUS TILL AFTER 15Z. FOR NOW WILL GO WITH THE NAM
SINCE SATELLITE IMAGES SHOW IT`S PERSISTENT TREND. OTHERWISE KGLD
WILL BE VFR TONIGHT WITH DECREASING NORTHWEST WIND TURNING LIGHT
AND VARIABLE TUESDAY AFTERNOON AS HIGH PRESSURE BUILDS INTO THE
AREA. KMCK WILL ALSO TURN VFR TUESDAY MORNING AND PERHAPS SLIGHTLY
EARLIER.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...LOCKHART
LONG TERM...RRH
AVIATION...FS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1124 PM CST Mon Dec 15 2014
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Tuesday)
Issued at 314 PM CST MON DEC 15 2014
Stacked system was centered in northern Missouri early this
afternoon with west to northwest winds bringing cold air in behind
and surface temps 5 to 15F below those of the pre- dawn hours.
Area of precipitation in deformation band on immediate west to
north flank of the system has weakened and exited, but water vapor
imagery supports RAP analysis of a minor wave rotating south into
south central Nebraska with narrow band of cloud top cooling and
light snow reported at CNK.
Recent HRRR and RAP output shows a steady decline in precip this
evening as the system enter the Ohio Valley overnight and this seems
very reasonable with heights rising and steady drying aloft. The
latter brings at least minor difficulty in precip type, but in this
band expect RH deep enough into the ice crystal formation layer for
rain and snow to dominate. Any accumulations should be quite light
and localized. Low cloud looks to be rather persistent tonight into
early Tuesday however with temps in this layer approaching -10C for
flurry possibilities but moisture depth shouldn`t support more than
brief bouts at best. Continued drying should bring some sunshine to
much of Tuesday, but high cloud entering the Rockies just upstream
of the upper ridge axis should increase toward sunset. Went a bit
above MOS averages on low temps tonight with the cloud in place.
.LONG TERM...(Tuesday Night through Monday)
Issued at 314 PM CST MON DEC 15 2014
Shortwave ridging and a dry airmass is expected to keep the
weather quiet for Tuesday night through Wednesday morning. With
some weak cold air advection as high pressure builds in, lows
Wednesday morning are expected to be around 20. Moisture appears
to begin returning north Wednesday. However models show the
shallow cold air holding in place Wednesday, keeping an easterly
surface winds and not mixing the boundary layer very deeply.
Therefore highs are forecast to remain in the middle 30s because
of this as well as increasing cloud cover.
Wednesday night and Thursday continue to look a little tricky with
regard to precip type. Models continue to show a perturbation
moving across the area Wednesday evening and a second one Thursday
morning. The better Q vector convergence and vorticity advection
may pass over southeast KS and the NAM and GFS forecast soundings
suggest there may not be enough saturation in the mid levels for
precip to be all snow. The one solution that continues to produce
a fair amount of QPF (around 2 tenths) Wednesday night is the
ECMWF, but it is difficult to know if there is as much dry air at
mid levels in its solution due to less vertical resolution. In all
it appears there is the potential for a weak progressive wave with
modest vertical motion to affect parts of the area with light
precipitation and have maintained POPs in the 30 to 40 percent
range. Best chances for measurable precip would be across east
central KS where the forcing is likely to be a little stronger.
Given the uncertainty provided by the NAM and GFS forecast
soundings, have introduced some freezing drizzle to the forecast
thinking mid levels may not be saturated and there would be no ice
in the cloud. Right now I would expect a light precip event
possibly affecting motorists late Wednesday night and Thursday
morning.
For Thursday night through Friday night, models seem to be
converging on a southern solution with the upper level jet
remaining over the southern U.S. and a developing surface low
tracking along the gulf coast. Even the 12Z GFS has trended
further south. Because of this, have trended POPS down a little
more for the period. Considered removing them all together but the
GFS still tries to bring energy down from the northwest and kicks
out some light QPF. Therefore held onto some slight chances for
precip.
Temps do not appear to be trending warmer until maybe Monday as
models hang onto the shallow cold airmass through much of the
weekend. By Monday there are signs that some low level return flow
could develop helping to bring some warm air back north. As for
the weather, the models continue to try and figure out this
pattern with split flow and energy coming off the Pacific. With
no obvious forcing progged to affect the forecast area through
Monday, have continued with a dry forecast for the weekend and
into next week.
&&
.AVIATION...(For the 06Z TAFs through 06Z Tuesday Night)
Issued at 1120 PM CST MON DEC 15 2014
MVFR conditions expected to continue through the overnight and
into the late morning hours. As expected the timing of the cloud
departure is in question. Have extended the VFR timing a few hours
later.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...65
LONG TERM...Wolters
AVIATION...Sanders
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1052 PM EST WED DEC 17 2014
.UPDATE...
ISSUED AT 1050 PM EST WED DEC 17 2014
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT TRENDS IN OBSERVATIONS
AND SATELLITE IMAGERY. STRATOCU HAS REDEVELOPED OVER THE SOUTHEASTERN
COUNTIES AND IS SPREADING BACK SOUTH ACROSS NORTHEASTERN KY AS WELL.
AS THE MID AND HIGH CLOUDS GRADUALLY ADVANCE IN FROM THE SOUTHWEST
CONFIDENCE IN THIS LOW DECK IS NOT EXTREMELY HIGH...BUT CLOUDS WILL
GRADUALLY INCREASE. WITH THE CLOUD FORECAST BEING LOW CONFIDENCE...IT
ALSO LEADS TO A TRICKY HOURLY TEMPERATURE FORECAST. MANY VALLEY
LOCATIONS THAT ARE CLOUD FREE ARE IN THE MID AND UPPER 20S AND MAY
DROP A COUPLE MORE DEGREES DURING BREAKS IN THE CLOUDS AND WHERE
CLOUDS DO NOT INCREASE FOR A FEW MORE HOURS. RECENT HRRR RUNS SUPPORT
A SLIGHTLY HIGHER CHANCE FOR LIGHT PRECIPITATION IN THE SOUTHWEST
REACHING THE GROUND NEAR DAWN AND OVERCOMING DRY AIR CENTERED NEAR
850 MB. THIS WOULD PROBABLY FALL AS ALL SNOW DUE TO WETBULBING. THIS
WOULD MAINLY BE FOR THE LAKE CUMBERLAND REGION COUNTIES OF WAYNE AND
MCCREARY AND POSSIBLY EXTENDING INTO ADJACENT PARTS OF SOUTHERN
PULASKI... SOUTHWEST LAUREL AND WESTERN WHITLEY COUNTIES.
OTHERWISE...THE LOW LEVELS SHOULD REMAIN TOO DRY FOR ANYTHING MORE
THAN VIRGA OR SOME STRAY FLURRIES OR SPRINKLES ON THU...BUT THERE
WILL BE PLENTY OF CLOUDS.
UPDATE ISSUED AT 815 PM EST WED DEC 17 2014
HOURLY GRIDS HAVE BEEN ADJUSTED TO ACCOUNT FOR THE CLEARING SOUTH OF
THE INTERSTATE 64 CORRIDOR AND HOURLY TEMPERATURE TRENDS. SOME
LOCATIONS SUCH AS JKL AND SME AS WELL AS VALLEY LOCATIONS ARE RUNNING
BELOW THE PREVIOUS FORECAST SO THE FIRST FEW HOURS WERE TRENDED
ACCORDINGLY ALTHOUGH MIN T FOR THE REST OF THE NIGHT WAS UNCHANGED FOR
MOST LOCATIONS. LIGHT PRECIP OR VIRGA WILL APPROACH THE SW PART OF THE
CWA TOWARD DAWN...BUT WILL BE STRUGGLING TO OVERCOME SIGNIFICANT LOW
LEVEL DRY AIR.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 310 PM EST WED DEC 17 2014
19Z SFC ANALYSIS SHOWS HIGH PRESSURE STARTING TO MORE EFFECTIVELY
MOVE INTO THE AREA. THIS IS BEGINNING TO BREAK UP THE LOW LEVEL CLOUD
COVER ACROSS AT LEAST THE SOUTHERN HALF OF THE CWA. THESE CLOUDS HAVE
KEPT TEMPERATURES IN CHECK SO FAR TODAY WITH READINGS GENERALLY IN
THE MID TO UPPER 30S NORTH AND IN THE LOWER 40S IN THE SOUTHEAST
WHERE SOME EARLY SUNSHINE IS MAKING ITS PRESENCE FELT. DEWPOINTS HAVE
DRIED OUT THROUGH THE DAY AND ARE NOW IN THE UPPER 20S TO LOWER 30S.
WINDS HAVE BEEN RELATIVELY LIGHT GENERALLY FROM THE WEST AT 5 TO 10
KTS TODAY.
THE MODELS ARE NOW IN PRETTY GOOD AGREEMENT ALOFT THROUGH THE SHORT
TERM PORTION OF THE FORECAST. THEY ALL DEPICT THE CLOSED...BUT
PROGRESSIVE...UPPER LOW THAT WILL SKIRT EAST THROUGH THE LOWER GREAT
LAKES THIS EVENING AND OVERNIGHT. A BRIEF PERIOD OF RIDGING WILL
FOLLOW INTO THURSDAY MORNING FOR EASTERN KENTUCKY BEFORE A RATHER
DAMPENED WAVE MOVES THROUGH LATER IN THE DAY AND THAT NIGHT WITH
SOME WEAK MID-LEVEL ENERGY FLOWING INTO THE CONFLUENCE ZONE EAST OF
THE AREA. WITH THE GENERAL MODEL AGREEMENT HAVE FOLLOWED THE HIGH
RESOLUTION NAM12 AND HRRR MOST CLOSELY FOR WEATHER DETAILS.
SENSIBLE WEATHER WILL FEATURE A BRIEF TIME OF CLEARING THIS EVENING
AND INTO TONIGHT THAT SHOULD ALLOW FOR SOME DECENT RADIATIONAL
COOLING AND RIDGE TO VALLEY TEMPERATURE DIFFERENCES THROUGH MIDNIGHT.
THEREAFTER...HIGH AND MID LEVEL CLOUDS WILL RETURN TO THE AREA FROM
WEST TO EAST AND PUT A CAP ON THE COOLING...LIMITING FURTHER TERRAIN
DIFFERENCES FOR THE REST OF THE NIGHT. THESE CLOUDS WILL ATTEMPT TO
BRING SNOW TO THE SOUTHWESTERN PARTS OF THE AREA BEFORE DAWN...BUT IT
WILL HAVE TO OVERCOME THE DRYING TAKING PLACE ATTM. ACCORDINGLY...
HAVE UNDERCUT QPF AND POPS FROM THE NAM/MET FOR LATE TONIGHT INTO
THURSDAY MORNING. THE AREA OF LOW PRESSURE RESPONSIBLE FOR THE PCPN
THREAT WILL DAMPEN THROUGH THE MORNING AND FADE OUT BY AFTERNOON. FOR
THIS...HAVE LIMITED THE PCPN THREAT TO JUST FLURRIES AND SPRINKLES
FOR THE SECOND HALF OF THE DAY. ADDITIONAL MOISTURE WILL PASS BY TO
THE NORTH LATER THAT EVENING AND A FEW FLURRIES WILL BE POSSIBLE FROM
THIS ALONG WITH ANOTHER COOL NIGHT.
AGAIN USED THE BCCONSSHORT AS A STARTING POINT FOR THE T/TD/WIND
GRIDS FOR THE FIRST 20 HOURS OR SO BEFORE POPULATING WITH THE
SUPERBLEND THEREAFTER. MINOR ADJUSTMENTS WERE MADE FOR TERRAIN
EFFECTS BOTH TONIGHT AND THURSDAY NIGHT. AS FOR POPS...ENDED UP A BIT
UNDER THE MET NUMBERS AND CLOSER TO THE DRIER MAV ONES FOR TONIGHT
AND THURSDAY GIVEN THE DRY AIR THAT WILL BE IN PLACE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 340 PM EST WED DEC 17 2014
FORECAST MODELS ARE IN GOOD AGREEMENT ON AN ACTIVE WEATHER PATTERN
WITH AT LEAST TWO SYSTEMS TO AFFECT US THROUGH THE PERIOD.
THE FIRST STORM OVER THE WEEKEND CONTINUES TO LOOK RATHER WEAK. A
LIGHT RAIN/SNOW MIX WILL MOVE INTO THE AREA OVERNIGHT FRIDAY NIGHT.
THIS WILL CHANGE TO ALL RAIN DURING THE DAY ON SATURDAY...FOLLOWED
BY PERHAPS BY A LITTLE MORE SNOW AS THE PRECIPITATION ENDS SATURDAY
NIGHT. THERE IS JUST NOT A LOT OF COLD AIR IN PLACE AND
PRECIPITATION LOOKS LIGHT SO ANY SNOW ACCUMULATIONS WILL BE VERY
LIGHT WITH THIS SYSTEM...IF ANY OCCUR AT ALL.
A MUCH MORE IMPRESSIVE STORM SYSTEM IS SHOWING UP IN THE COMPUTER
MODELS FOR THE MIDDLE OF NEXT WEEK...WITH DECENT AGREEMENT ON AN
IMPACTFUL SYSTEM JUST IN TIME FOR PEAK HOLIDAY TRAVEL. AN UPPER
LEVEL TROUGH WILL DIG IN OVER THE PLAINS EARLY IN THE WEEK AND
BECOME NEGATIVELY TILTED OVER THE OHIO VALLEY MID WEEK. THIS CAUSES
EXPLOSIVE DEEPENING OF A SURFACE LOW PRESSURE WHICH IS PROGGED TO
DEVELOP AND TRACK OVER US OR VERY CLOSE TO US ON ITS WAY NORTH TO
THE GREAT LAKES. THIS SYSTEM IS STILL WAY TOO FAR OUT IN THE FUTURE
TO PINPOINT EXACTLY WHAT TYPE OF WEATHER WE WILL BE DEALING
WITH...BUT RAIN...WIND AND SNOW ARE ALL ON THE TABLE FROM TUESDAY
THROUGH WEDNESDAY...AND POTENTIALLY BEYOND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 735 PM EST WED DEC 17 2014
THE LOW CLOUDS IN THE MVFR RANGE HAVE BROKEN UP AS DRIER AIR HAS
MOVED INTO THE AREA ALTHOUGH...ALTHOUGH THESE CONTINUE TO LINGER
ALONG THE INTERSTATE 64 CORRIDOR FROM LEX TO HTS INCLUDING SYM AND
IOB AND MAY LINGER AT SYM FOR THE FIRST FEW HOURS OF THE PERIOD...AND
CONFIDENCE IN TIMING OF CLEARING THERE IS LOW. ALSO...HIGH AND SOME
MID CLOUDS WILL START BUILDING IN OVER THE AREA FROM THE WEST AND
SOUTHWEST OVER THE FIRST 3 TO 8 HOURS OF THE PERIOD BUT THESE WILL
REMAIN IN THE VFR RANGE. THIS NEXT SYSTEM DOES BRING THE POTENTIAL
FOR SOME LIGHT SNOW TO THE SOUTHWEST PART OF THE AREA AFTER THE 10Z
TO 12Z PERIOD. DUE TO DRY LOW LEVEL AIR THIS WILL BRING A GRADUAL
LOWERING OF CIGS DOWN INTO THE MVFR RANGE BY THE LAST 12 HOURS OF THE
PERIOD...BUT VIS WILL LIKELY REMAIN MOSTLY IN THE VFR RANGE. LIGHT
WINS ARE ANTICIPATED THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...ABE
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
824 PM EST WED DEC 17 2014
.UPDATE...
ISSUED AT 815 PM EST WED DEC 17 2014
HOURLY GRIDS HAVE BEEN ADJUSTED TO ACCOUNT FOR THE CLEARING SOUTH OF
THE INTERSTATE 64 CORRIDOR AND HOURLY TEMPERATURE TRENDS. SOME
LOCATIONS SUCH AS JKL AND SME AS WELL AS VALLEY LOCATIONS ARE RUNNING
BELOW THE PREVIOUS FORECAST SO THE FIRST FEW HOURS WERE TRENDED
ACCORDINGLY ALTHOUGH MIN T FOR THE REST OF THE NIGHT WAS UNCHANGED FOR
MOST LOCATIONS. LIGHT PRECIP OR VIRGA WILL APPROACH THE SW PART OF THE
CWA TOWARD DAWN...BUT WILL BE STRUGGLING TO OVERCOME SIGNIFICANT LOW
LEVEL DRY AIR.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 310 PM EST WED DEC 17 2014
19Z SFC ANALYSIS SHOWS HIGH PRESSURE STARTING TO MORE EFFECTIVELY
MOVE INTO THE AREA. THIS IS BEGINNING TO BREAK UP THE LOW LEVEL CLOUD
COVER ACROSS AT LEAST THE SOUTHERN HALF OF THE CWA. THESE CLOUDS HAVE
KEPT TEMPERATURES IN CHECK SO FAR TODAY WITH READINGS GENERALLY IN
THE MID TO UPPER 30S NORTH AND IN THE LOWER 40S IN THE SOUTHEAST
WHERE SOME EARLY SUNSHINE IS MAKING ITS PRESENCE FELT. DEWPOINTS HAVE
DRIED OUT THROUGH THE DAY AND ARE NOW IN THE UPPER 20S TO LOWER 30S.
WINDS HAVE BEEN RELATIVELY LIGHT GENERALLY FROM THE WEST AT 5 TO 10
KTS TODAY.
THE MODELS ARE NOW IN PRETTY GOOD AGREEMENT ALOFT THROUGH THE SHORT
TERM PORTION OF THE FORECAST. THEY ALL DEPICT THE CLOSED...BUT
PROGRESSIVE...UPPER LOW THAT WILL SKIRT EAST THROUGH THE LOWER GREAT
LAKES THIS EVENING AND OVERNIGHT. A BRIEF PERIOD OF RIDGING WILL
FOLLOW INTO THURSDAY MORNING FOR EASTERN KENTUCKY BEFORE A RATHER
DAMPENED WAVE MOVES THROUGH LATER IN THE DAY AND THAT NIGHT WITH
SOME WEAK MID-LEVEL ENERGY FLOWING INTO THE CONFLUENCE ZONE EAST OF
THE AREA. WITH THE GENERAL MODEL AGREEMENT HAVE FOLLOWED THE HIGH
RESOLUTION NAM12 AND HRRR MOST CLOSELY FOR WEATHER DETAILS.
SENSIBLE WEATHER WILL FEATURE A BRIEF TIME OF CLEARING THIS EVENING
AND INTO TONIGHT THAT SHOULD ALLOW FOR SOME DECENT RADIATIONAL
COOLING AND RIDGE TO VALLEY TEMPERATURE DIFFERENCES THROUGH MIDNIGHT.
THEREAFTER...HIGH AND MID LEVEL CLOUDS WILL RETURN TO THE AREA FROM
WEST TO EAST AND PUT A CAP ON THE COOLING...LIMITING FURTHER TERRAIN
DIFFERENCES FOR THE REST OF THE NIGHT. THESE CLOUDS WILL ATTEMPT TO
BRING SNOW TO THE SOUTHWESTERN PARTS OF THE AREA BEFORE DAWN...BUT IT
WILL HAVE TO OVERCOME THE DRYING TAKING PLACE ATTM. ACCORDINGLY...
HAVE UNDERCUT QPF AND POPS FROM THE NAM/MET FOR LATE TONIGHT INTO
THURSDAY MORNING. THE AREA OF LOW PRESSURE RESPONSIBLE FOR THE PCPN
THREAT WILL DAMPEN THROUGH THE MORNING AND FADE OUT BY AFTERNOON. FOR
THIS...HAVE LIMITED THE PCPN THREAT TO JUST FLURRIES AND SPRINKLES
FOR THE SECOND HALF OF THE DAY. ADDITIONAL MOISTURE WILL PASS BY TO
THE NORTH LATER THAT EVENING AND A FEW FLURRIES WILL BE POSSIBLE FROM
THIS ALONG WITH ANOTHER COOL NIGHT.
AGAIN USED THE BCCONSSHORT AS A STARTING POINT FOR THE T/TD/WIND
GRIDS FOR THE FIRST 20 HOURS OR SO BEFORE POPULATING WITH THE
SUPERBLEND THEREAFTER. MINOR ADJUSTMENTS WERE MADE FOR TERRAIN
EFFECTS BOTH TONIGHT AND THURSDAY NIGHT. AS FOR POPS...ENDED UP A BIT
UNDER THE MET NUMBERS AND CLOSER TO THE DRIER MAV ONES FOR TONIGHT
AND THURSDAY GIVEN THE DRY AIR THAT WILL BE IN PLACE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 340 PM EST WED DEC 17 2014
FORECAST MODELS ARE IN GOOD AGREEMENT ON AN ACTIVE WEATHER PATTERN
WITH AT LEAST TWO SYSTEMS TO AFFECT US THROUGH THE PERIOD.
THE FIRST STORM OVER THE WEEKEND CONTINUES TO LOOK RATHER WEAK. A
LIGHT RAIN/SNOW MIX WILL MOVE INTO THE AREA OVERNIGHT FRIDAY NIGHT.
THIS WILL CHANGE TO ALL RAIN DURING THE DAY ON SATURDAY...FOLLOWED
BY PERHAPS BY A LITTLE MORE SNOW AS THE PRECIPITATION ENDS SATURDAY
NIGHT. THERE IS JUST NOT A LOT OF COLD AIR IN PLACE AND
PRECIPITATION LOOKS LIGHT SO ANY SNOW ACCUMULATIONS WILL BE VERY
LIGHT WITH THIS SYSTEM...IF ANY OCCUR AT ALL.
A MUCH MORE IMPRESSIVE STORM SYSTEM IS SHOWING UP IN THE COMPUTER
MODELS FOR THE MIDDLE OF NEXT WEEK...WITH DECENT AGREEMENT ON AN
IMPACTFUL SYSTEM JUST IN TIME FOR PEAK HOLIDAY TRAVEL. AN UPPER
LEVEL TROUGH WILL DIG IN OVER THE PLAINS EARLY IN THE WEEK AND
BECOME NEGATIVELY TILTED OVER THE OHIO VALLEY MID WEEK. THIS CAUSES
EXPLOSIVE DEEPENING OF A SURFACE LOW PRESSURE WHICH IS PROGGED TO
DEVELOP AND TRACK OVER US OR VERY CLOSE TO US ON ITS WAY NORTH TO
THE GREAT LAKES. THIS SYSTEM IS STILL WAY TOO FAR OUT IN THE FUTURE
TO PINPOINT EXACTLY WHAT TYPE OF WEATHER WE WILL BE DEALING
WITH...BUT RAIN...WIND AND SNOW ARE ALL ON THE TABLE FROM TUESDAY
THROUGH WEDNESDAY...AND POTENTIALLY BEYOND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 735 PM EST WED DEC 17 2014
THE LOW CLOUDS IN THE MVFR RANGE HAVE BROKEN UP AS DRIER AIR HAS
MOVED INTO THE AREA ALTHOUGH...ALTHOUGH THESE CONTINUE TO LINGER
ALONG THE INTERSTATE 64 CORRIDOR FROM LEX TO HTS INCLUDING SYM AND
IOB AND MAY LINGER AT SYM FOR THE FIRST FEW HOURS OF THE PERIOD...AND
CONFIDENCE IN TIMING OF CLEARING THERE IS LOW. ALSO...HIGH AND SOME
MID CLOUDS WILL START BUILDING IN OVER THE AREA FROM THE WEST AND
SOUTHWEST OVER THE FIRST 3 TO 8 HOURS OF THE PERIOD BUT THESE WILL
REMAIN IN THE VFR RANGE. THIS NEXT SYSTEM DOES BRING THE POTENTIAL
FOR SOME LIGHT SNOW TO THE SOUTHWEST PART OF THE AREA AFTER THE 10Z
TO 12Z PERIOD. DUE TO DRY LOW LEVEL AIR THIS WILL BRING A GRADUAL
LOWERING OF CIGS DOWN INTO THE MVFR RANGE BY THE LAST 12 HOURS OF THE
PERIOD...BUT VIS WILL LIKELY REMAIN MOSTLY IN THE VFR RANGE. LIGHT
WINS ARE ANTICIPATED THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...ABE
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
315 PM EST TUE DEC 16 2014
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 315 PM EST TUE DEC 16 2014
19Z SFC ANALYSIS SHOWS A FAIRLY DEEP AREA OF LOW PRESSURE LIFTING
NORTHEAST THROUGH THE EASTERN GREAT LAKES. THE COLD FRONT ASSOCIATED
WITH THIS SYSTEM IS NOW THROUGH EASTERN KENTUCKY AND AS A RESULT
GUSTY WEST WINDS ARE BRINGING IN A COLDER AIR MASS. AS IT DOES SO...
IT IS ALSO GENERATING A SUBSTANTIAL AREA OF DRIZZLE AND LOWER CIGS.
TEMPERATURES VARY FROM THE LOW 40S WEST TO NEAR 50S EAST ACROSS THE
CWA WITH DEWPOINTS IN THE UPPER 30S TO LOWER 40S.
THE MODELS ARE IN DECENT ENOUGH AGREEMENT ALOFT THROUGH THE SHORT
TERM PORTION OF THE FORECAST AS THEY ALL DAMPEN OUT THE CURRENT
TROUGH OVER THE AREA WHILE ABSORBING IT INTO THE MAIN MID LEVEL LOW
OVER THE UPPER MIDWEST. THIS WILL KEEP FAST...WEST TO EAST...FLOW
ABOVE EASTERN KENTUCKY INTO THE DAY WEDNESDAY...THOUGH MODEL
DIFFERENCES START TO MAGNIFY BY DAWN. THE ECMWF IS SLOWER MOVING
THIS MIDWEST LOW EAST COMPARED TO THE GEM AND GFS WHICH WILL ALSO
SERVE TO KEEP OUR HEIGHTS SLIGHTLY SUPPRESSED INTO WEDNESDAY EVENING.
DESPITE THIS...THE PREFERRED ECMWF DOES NOT LAG IN BRINGING THE NEXT
BATCH OF ENERGY INTO THE REGION FROM A QUICK MOVING WAVE PASSING OUT
OF THE SOUTHERN PLAINS. THIS WILL SEEP INTO OUR SOUTHWEST PARTS BY
THURSDAY MORNING. FOR THE FORECAST...FOLLOWED A BLEND OF THE HIGHER
RESOLUTION HRRR AND NAM12 WITH SOME ADJUSTMENT TOWARD THE MAIN
FEATURES IN THE LATEST ECMWF.
A DREARY EVENING AND OVERNIGHT IS ANTICIPATED THROUGH EASTERN
KENTUCKY AS LOW CIGS AND DRIZZLE WILL DOMINATE UNDER A SUBSIDENCE
INVERSION...PARTICULARLY OVER THE NORTHERN HALF THE CWA. THERE IS A
CONCERN THAT THE HIGHER POINTS OF EASTERN KENTUCKY FALL TO
FREEZING...OR A COUPLE OF DEGREES BELOW...BY DAWN GIVEN THE CAA
OVERNIGHT. COMBINED WITH THE AREAS OF DRIZZLE STILL AROUND...THERE
WILL BE A THREAT OF FREEZING DRIZZLE GENERALLY ABOVE 2000 FEET. FOR
THIS...WILL ISSUE AN SPS FROM LATE TONIGHT INTO THURSDAY MORNING FOR
OUR SOUTHEASTERN-MOST COUNTIES WITH THAT HIGHER TERRAIN. THE LOW
CLOUDS WILL PROBABLY HOLD TOUGH INTO THE FIRST PART OF THE DAY
WEDNESDAY BUT THERE COULD BE SOME BREAKUP MAKING FOR A BRIEF PERIOD
OF SUNSHINE DURING THE AFTERNOON AHEAD OF THE NEXT BATCH OF HIGHER
CLOUDS DUE IN HERE LATER THAT EVENING. THESE NEXT CLOUDS WILL QUICKLY
INCREASE AND LOWER THROUGH THE NIGHT WITH EVEN SOME LIGHT RAIN OR
SNOW POSSIBLE BY DAWN THURSDAY...THOUGH TEMPERATURES WILL BE MILDER
THAN TONIGHT IN MOST PLACES.
USED THE BCCONSSHORT AS A STARTING POINT FOR THE T/TD/WIND GRIDS FOR
THE FIRST 20 HOURS BEFORE POPULATING WITH THE SUPERBLEND THEREAFTER.
THESE WERE THEN SUBJECTED TO MINOR ADJUSTMENTS FOR TERRAIN EFFECTS
MAINLY TONIGHT AND WEDNESDAY NIGHT. AS FOR POPS...ENDED UP JUST ABOVE
THE HIGHER MET MOS GUIDANCE TONIGHT GIVEN THE LOW QPF BUT MODERATE
POPS WITH EXTRA EMPHASIS ON DRIZZLE AS PTYPE. ALSO...FOR LATE
WEDNESDAY WENT A BIT HIGHER THEN GUIDANCE IN THE SOUTHWEST GIVEN THE
FAST FLOW REGIME.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 245 PM EST TUE DEC 16 2014
PROGRESSIVE PATTERN WILL CONTINUE THROUGH THE EXTENDED. THE PERIOD
WILL START AS A MID LEVEL TROUGH CROSSES INTO THE OHIO RIVER VALLEY
ON THURSDAY. MODELS HAVE TRENDED MORE AGGRESSIVE WITH THIS FEATURE
WITH THE 12Z SUITE OF MODELS WITH GFS EVEN SHOWING SOME MODEST LIFT
ABOVE 850MB. THE MAIN LIMITING FACTOR FOR PRECIPITATION ON THURSDAY
WILL BE THE LOW LEVEL DRY AIR. HOWEVER...GIVEN THE DEEP MOISTURE
STARTING AROUND 5KFT...THIS SHOULD BE ENOUGH TO AT LEAST WARRANT A
CHANCE OF MEASURABLE PRECIPITATION REACHING THE GROUND.
HOWEVER...THIS PRECIPITATION MAY DRY UP AS IT TRIES TO PUSH
NORTHWARD THROUGH THE DAY. THUS...PLAN TO GO WITH CHANCE POPS ACROSS
THE SOUTH...TRAILING OFF TO SLIGHT CHANCE IN THE NORTH. ALL OF THIS
PRECIPITATION AS EXPECTED WILL REMAIN LIGHT...BUT SOME SNOWFLAKES
COULD MIX IN AT TIMES THROUGH THE DAY. HIGH PRESSURE WILL PROVIDE
DRY WEATHER THURSDAY NIGHT THROUGH FRIDAY.
THE WEATHER TURNS MORE INTERESTING BY FRIDAY NIGHT THROUGH SATURDAY
AS A SOUTHERN STREAM SHORTWAVE PUSHES EAST ACROSS THE SOUTHERN TIER
OF THE US. THIS SYSTEM IS NOT EXPECTED TO GET MUCH HELP FROM THE
NORTHERN STREAM...AND THUS...NOT MUCH COLD AIR IS EXPECTED TO GET
WORKED INTO THIS SYSTEM. THIS FACT...COMBINED WITH A WEAKENING AREA
OF LOW PRESSURE TRACKING ACROSS THE GULF COAST STATES WILL LIKELY
YIELD VERY LITTLE SNOW POTENTIAL. HOWEVER...WE ARE ON THE NORTH SIDE
OF THIS SYSTEM...WHICH WOULD BE THE BEST SPOT FOR ANY SNOW.
PRECIPITATION IS EXPECTED TO SPREAD INTO THE AREA LATE FRIDAY NIGHT
AND CONTINUE THROUGH SATURDAY. BEST SNOW POTENTIAL MAY BE AT THE
ONSET FRIDAY NIGHT...BUT AGAIN...PRECIPITATION RATES MAY BE FAIRLY
LIMITED...KEEPING SNOW AMOUNTS FROM BEING ALL THAT HIGH. IN
FACT...WE COULD SEE A MIX OF RAIN/SNOW RIGHT THROUGH SATURDAY WITH
VERY LITTLE SNOW ACCUMULATION FOR MUCH OF THE AREA. THE ECMWF
REMAINS THE COLDER OF THE MODELS SUGGESTING BETTER SNOW
POTENTIAL...WHILE THE GFS HAS MAINTAINED ITS ALL RAIN FORECAST.
GOING WITH A COMPROMISE ON HIGHS ON SATURDAY WOULD BE TEMPERATURES
AROUND 40 BY THE AFTERNOON ACROSS MUCH OF THE AREA. ITS POSSIBLE
SOME COOLER READINGS IN THE 30S COULD KEEP MORE SNOW GOING A BIT
LONGER ACROSS THE NORTHERN PORTION OF THE AREA...BUT WITH WEAK
PRECIP RATES...COMBINED WITH ABOVE FREEZING TEMPERATURES...SHOULD
REALLY CUT INTO ANY SNOWFALL POTENTIAL EVEN WITH THE COLDER ECMWF
SOLUTION. PRECIPITATION WILL WIND DOWN BY SATURDAY NIGHT GOING OVER
TO A PERIOD OF LIKELY DRIZZLE.
DRY WEATHER WILL RETURN FOR SUNDAY AND PERSIST INTO THE EARLY PART
OF NEXT WEEK. TEMPERATURES ARE EXPECTED TO REMAIN FAIRLY SEASONABLE
THROUGH THE END OF THE FORECAST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 145 PM EST TUE DEC 16 2014
THE COLD FRONT HAS PASSED THROUGH EASTERN KENTUCKY TAKING THE LIGHT
RAINS ALONG WITH IT. HOWEVER...A LARGE AREA OF DRIZZLE DOES FOLLOW
THIS BOUNDARY AND WILL AFFECT MUCH OF THE FA INTO THE EVENING. IN
FACT...FORECAST SOUNDINGS AND TIME HEIGHTS CONTINUE TO INDICATE A
STRONG SUBSIDENCE INVERSION BEHIND THE FRONT...WITH LOW LEVEL
MOISTURE TRAPPED THROUGH MOST OF THE TAF PERIOD. THIS WILL LEAD TO
LOWERING CIGS AND THE POTENTIAL FOR DRIZZLE THROUGH WEDNESDAY
MORNING. FUEL ALTERNATES ARE LIKELY AS WE HEAD INTO THE OVERNIGHT
HOURS. ANOTHER CONCERN WILL BE THE WINDS. EXPECT WINDS AT THE SURFACE
TO STAY UP FROM THE WEST WITH GUSTS BETWEEN 15 AND 20 KTS THROUGH
THE REST OF THE AFTERNOON. THE OVERNIGHT SUBSIDENCE INVERSION SHOULD
ALLOW SFC WINDS TO DIE DOWN AND BECOME LIGHT FOLLOWING SUNSET. THE
WINDS WILL PICK UP FROM THE WEST TO NORTHWEST DURING THE DAY
WEDNESDAY AT 5 TO 10 KTS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
205 PM EST TUE DEC 16 2014
.UPDATE...
ISSUED AT 205 PM EST TUE DEC 16 2014
DID A QUICK UPDATED TO FINE TUNE THE POPS AND WX THROUGH THE REST OF
THE AFTERNOON ALSO MATCHED UP THE HOURLY TEMPS AND DEWPOINTS WITH THE
CURRENT CONDITIONS AND TRENDS. THESE UPDATED GRIDS HAVE BEEN SENT TO
THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 1020 AM EST TUE DEC 16 2014
14Z SFC ANALYSIS SHOWS A FAIRLY DEEP AREA OF LOW PRESSURE MOVING
THROUGH THE NORTHERN OHIO VALLEY. A COLD FRONT EXTENDS SOUTH OF THIS
AND IS CURRENTLY CROSSING EAST KENTUCKY...JUST REACHING JKL. A LINE
OF LIGHT RAIN ACCOMPANIES THIS BOUNDARY ALONG WITH AREAS OF DRIZZLE
IN ITS WAKE. THE EARLIER THUNDERSTORMS COMING OUT OF SOUTHERN INDIANA
APPEARS TO HAVE SETTLED SO THAT LIGHT RAIN AND DRIZZLE WILL BE THE
MAIN WEATHER TYPE FOR OUR AREA INTO THE AFTERNOON. IN ADDITION TO THE
PCPN CHANCES WITH THE FRONT...GUSTY WINDS FROM THE WEST ACCOMPANY AND
TRAIL THE BOUNDARY. THESE WILL BRING IN COOLER AIR TO EASTERN
KENTUCKY THROUGH THE REST OF THE DAY. THIS MEANS THAT WE HAVE LIKELY
REACHED OUR HIGHS FOR THE DAY IN MOST PLACES...PARTICULARLY IN THE
EAST WHERE PATCHES OF SUNSHINE IN THE WAKE OF THE LOW/S WARM FRONT
HAVE SENT READINGS INTO THE LOW AND MID 50S. 40S WILL FOLLOW WHILE
DEWPOINTS WILL REMAIN RATHER UNIFORM ON EITHER SIDE OF THE FRONT...
GENERALLY IN THE LOW AND MID 40S. HAVE UPDATED THE FORECAST TO
REFLECT THE ABOVE CHANGES AND TO ALSO INFUSE SOME OF THE LATEST HIGH
RESOLUTION GUIDANCE FROM THE HRRR AND 12Z NAM. THESE GRIDS HAVE BEEN
SENT TO THE NDFD AND WEB SERVERS. WILL ALSO UPDATE THE ZONES AND
HWO...MAINLY TO REMOVE THE THUNDER CHANCES THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 351 AM EST TUE DEC 16 2014
A SURFACE LOW PRESSURE CENTER IS CURRENTLY RIDING JUST NORTH OF THE
OHIO RIVER VALLEY...LOCATED SOMEWHERE FAIRLY CLOSE TO INDIANAPOLIS.
AS THIS LOW CONTINUES TO PROGRESS ENEWARD...IT IS CURRENTLY PULLING
A WARM FRONT FROM SW TO NE ACROSS THE CWA /SHOULD BE THROUGH BY
AROUND 12Z/...AND THEN WILL FOLLOW UP WITH A COLD FRONT PASSING
THROUGH THE CWA FROM WEST TO EAST BETWEEN APPROX 10Z AND 15Z. WITH
EACH OF THESE SYSTEMS...WE ARE CONTINUING TO PICK UP LIGHT SHOWER
ACTIVITY...WITH SCATTERED TO WIDESPREAD RETURNS ACROSS PORTIONS OF
EASTERN KY IN RESPONSE TO THE WARM FRONT...AND ANOTHER AREA JUST
ALONG THE COLD FRONT ACROSS WEST CENTRAL KY. UNFORTUNATELY...MODELS
ARE STILL HAVING A HARD TIME SHOWING A WELL DEFINED PRECIP FORECAST
FOR THIS SYSTEM. LEANED ON A MIXTURE OF RADAR TRENDS...THE HRRR AND
RUC /WHICH SEEMED TO HAVE THE BEST HANDLE ON THE CURRENT
SITUATION/...AND SOME LESSER INFLUENCE FROM A BLEND OF OTHER HI RES
MODELS...TO COME UP WITH THE FORECAST FOR THE PROGRESSION OF THE RAIN
AS WE HEAD THROUGH TODAY. AS SUCH...THE CURRENT RAIN /AND ISOLATED
THUNDER/ OVER CENTRAL KY SHOULD MAKE IT INTO OUR WESTERN CWA WITHIN
THE NEXT FEW HOURS /AROUND 10 TO 11Z/...WHILE CHANCES WILL INCREASE
ALONG MUCH OF THE NE CWA AS THE LOW TRACKS JUST TO OUR NORTH.
DID CONTINUE TO NOTE THAT MOST OF THIS MOISTURE SHOWS UP AS BEING
FAIRLY SHALLOW IN THE FORECAST SOUNDINGS THROUGH TODAY...SO DON/T
EXPECT ANYTHING OTHER THAN LIGHT SHOWERS. ONCE DRY AIR MOVES IN
BEHIND THE COLD FRONT THIS AFTERNOON...EXPECT IT TO ONCE AGAIN TRAP
A LAYER OF LOW LEVEL MOISTURE NEAR THE SURFACE...WHERE IT WILL
LINGER THROUGH AROUND 15Z TOMORROW...LONG AFTER THE INFLUENCE OF THE
LOW PRESSURE SYSTEM. AS SUCH...WHILE SOME OF THIS MOISTURE WILL FALL
AS LIGHT RAIN DURING THE DAY TODAY...IT STANDS TO REASON THAT IT
COULD BE MIXED IN WITH DRIZZLE IN SOME LOCATIONS...AND THEN CHANGE
OVER TO ALL DRIZZLE TONIGHT AS MOISTURE BECOMES INCREASINGLY SHALLOW.
TRIED TO REFLECT THIS IN THE WEATHER GRIDS...WITH A MIXTURE OF
ISOLATED/SLIGHT CHANCE RAIN AND PATCHY DRIZZLE...THEN LIGHT DRIZZLE
LINGERING THROUGH TOMORROW MORNING.
TEMPS WILL RISE SOME THROUGHOUT THE MORNING...WITH SOME PLACES IN
THE EAST POSSIBLY PULLING OUT SOME LOW 50S DUE TO THE WAA BEHIND THE
WARM FRONT...BUT SHOULD GENERALLY FALL FROM WEST TO EAST DURING THE
AFTERNOON AS COLDER AIR FILTERS IN BEHIND THE COLD FRONTAL PASSAGE.
WINDS WILL ALSO CONTINUE TO BE GUSTY AHEAD AND JUST BEHIND THE
FRONT...DYING DOWN AS WE HEAD INTO THE EVENING HOURS. THE PUSH OF
COLDER AIR COULD ALLOW FOR SOME BELOW FREEZING TEMPS BY
OVERNIGHT...NAMELY IN THE HIGHEST TERRAIN IN THE SE. AS SUCH...SOME
FREEZING DRIZZLE IN THESE LOCATIONS CANNOT BE RULED OUT. DID GO AHEAD
AND KEEP A MENTION OF THIS IN THE GRIDS...BUT WILL NEED TO KEEP AN
EYE OUT AS WE HEAD INTO TONIGHT IN CASE ANY FURTHER ACTION NEEDS TO BE
TAKEN. HIGHS WEDNESDAY WILL FALL BELOW SEASONABLE NORMS ONCE
MORE...TOPPING OUT IN THE LOW 40S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 419 AM EST TUE DEC 16 2014
THE MODELS ARE IN GOOD AGREEMENT WITH A PROGRESSIVE LONG WAVE PATTERN
TO HOLD ON THROUGH THE END OF THE WEEK...FOLLOWED BY AMPLIFICATION
INTO EARLY NEXT WEEK. DETAILS WITHIN THE LONG WAVE PATTERN CONTINUE
TO BE CHALLENGING...SO HAVE STUCK FAIRLY CLOSE TO A BLEND OF THE
GUIDANCE...WHILE STEERING THE FORECAST TOWARDS GENERAL MODEL TRENDS
SEEN IN THE PAST FEW DAYS.
THE SOUTHERN STREAM WILL MAINLY BE PROVIDING OUR WEATHER THROUGH THE
PERIOD...AS TROUGHING ACROSS THE SOUTHWEST CONUS GRADUALLY
TRANSLATES EAST. INITIALLY...A DAMPENING SHORT WAVE TROUGH WILL EJECT
OUT OF THE MAIN TROUGH...AFFECTING OUR AREA VERY LATE WEDNESDAY NIGHT
INTO THURSDAY. FORCING WILL BE CONFINED TO THE MID AND UPPER
LEVELS...AND DEEPER MOISTURE CONTINUES TO BE LACKING ACROSS EASTERN
KENTUCKY. AS SUCH...WILL MAINTAIN A SLIGHT CHANCE OF SNOW/RAIN
GENERALLY NEAR AND SOUTH OF THE HAL ROGERS AND HIGHWAY 80 CORRIDORS.
THE MAIN TROUGH AXIS WILL THEN MOVE ACROSS THE GULF COAST STATES AND
EVENTUALLY SWING ACROSS THE SOUTHERN APPALACHIANS BY THE WEEKEND.
THE MODELS HAVE GENERALLY SHOWN A MORE SOUTHERLY TRACK WITH THE
ASSOCIATED SURFACE LOW. THE GFS HAS ALSO TRENDED NOTICEABLY SLOWER
WITH THE PRECIPITATION ONSET. THE THERMAL PROFILES CONTINUE TO DIFFER
QUITE A BIT...WITH THE ECMWF COOLER AND THE GFS WARMER. AS
SUCH...HAVE MAINTAINED A BROAD BRUSH WITH THE RAIN/SNOW POTENTIAL
UNTIL CONFIDENCE INCREASES. PRECIPITATION WILL BEGIN FRIDAY
NIGHT...WITH THE OVERALL BEST CHANCE FOR THE ENTIRE AREA ON SATURDAY.
PRECIPITATION WILL THEN TAPER OFF QUICKLY SATURDAY NIGHT...WITH ONLY
A SMALL CHANCE OF A FEW LINGERING SHOWERS IN THE FAR SOUTHEAST
THROUGH SUNDAY MORNING WITH UPSLOPE FLOW IN PLACE. HIGH PRESSURE WILL
THEN TAKE HOLD INTO EARLY NEXT WEEK...BEFORE A DEEPER TROUGH
APPROACHES FROM THE WEST.
BELOW NORMAL TEMPERATURES WILL REIGN THROUGH THE PERIOD. STUCK FAIRLY
CLOSE TO THE BLENDED GUIDANCE GIVEN THE UNCERTAINTY...HOWEVER DID
ALLOW FOR A MORE DIURNALLY LIMITED TEMPERATURE REGIME DURING THE
PERIODS OF GREATER PRECIPITATION CHANCES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 145 PM EST TUE DEC 16 2014
THE COLD FRONT HAS PASSED THROUGH EASTERN KENTUCKY TAKING THE LIGHT
RAINS ALONG WITH IT. HOWEVER...A LARGE AREA OF DRIZZLE DOES FOLLOW
THIS BOUNDARY AND WILL AFFECT MUCH OF THE FA INTO THE EVENING. IN
FACT...FORECAST SOUNDINGS AND TIME HEIGHTS CONTINUE TO INDICATE A
STRONG SUBSIDENCE INVERSION BEHIND THE FRONT...WITH LOW LEVEL
MOISTURE TRAPPED THROUGH MOST OF THE TAF PERIOD. THIS WILL LEAD TO
LOWERING CIGS AND THE POTENTIAL FOR DRIZZLE THROUGH WEDNESDAY
MORNING. FUEL ALTERNATES ARE LIKELY AS WE HEAD INTO THE OVERNIGHT
HOURS. ANOTHER CONCERN WILL BE THE WINDS. EXPECT WINDS AT THE SURFACE
TO STAY UP FROM THE WEST WITH GUSTS BETWEEN 15 AND 20 KTS THROUGH
THE REST OF THE AFTERNOON. THE OVERNIGHT SUBSIDENCE INVERSION SHOULD
ALLOW SFC WINDS TO DIE DOWN AND BECOME LIGHT FOLLOWING SUNSET. THE
WINDS WILL PICK UP FROM THE WEST TO NORTHWEST DURING THE DAY
WEDNESDAY AT 5 TO 10 KTS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...JMW
LONG TERM...GEOGERIAN
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1020 AM EST TUE DEC 16 2014
.UPDATE...
ISSUED AT 1020 AM EST TUE DEC 16 2014
14Z SFC ANALYSIS SHOWS A FAIRLY DEEP AREA OF LOW PRESSURE MOVING
THROUGH THE NORTHERN OHIO VALLEY. A COLD FRONT EXTENDS SOUTH OF THIS
AND IS CURRENTLY CROSSING EAST KENTUCKY...JUST REACHING JKL. A LINE
OF LIGHT RAIN ACCOMPANIES THIS BOUNDARY ALONG WITH AREAS OF DRIZZLE
IN ITS WAKE. THE EARLIER THUNDERSTORMS COMING OUT OF SOUTHERN INDIANA
APPEARS TO HAVE SETTLED SO THAT LIGHT RAIN AND DRIZZLE WILL BE THE
MAIN WEATHER TYPE FOR OUR AREA INTO THE AFTERNOON. IN ADDITION TO THE
PCPN CHANCES WITH THE FRONT...GUSTY WINDS FROM THE WEST ACCOMPANY AND
TRAIL THE BOUNDARY. THESE WILL BRING IN COOLER AIR TO EASTERN
KENTUCKY THROUGH THE REST OF THE DAY. THIS MEANS THAT WE HAVE LIKELY
REACHED OUR HIGHS FOR THE DAY IN MOST PLACES...PARTICULARLY IN THE
EAST WHERE PATCHES OF SUNSHINE IN THE WAKE OF THE LOW/S WARM FRONT
HAVE SENT READINGS INTO THE LOW AND MID 50S. 40S WILL FOLLOW WHILE
DEWPOINTS WILL REMAIN RATHER UNIFORM ON EITHER SIDE OF THE FRONT...
GENERALLY IN THE LOW AND MID 40S. HAVE UPDATED THE FORECAST TO
REFLECT THE ABOVE CHANGES AND TO ALSO INFUSE SOME OF THE LATEST HIGH
RESOLUTION GUIDANCE FROM THE HRRR AND 12Z NAM. THESE GRIDS HAVE BEEN
SENT TO THE NDFD AND WEB SERVERS. WILL ALSO UPDATE THE ZONES AND
HWO...MAINLY TO REMOVE THE THUNDER CHANCES THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 351 AM EST TUE DEC 16 2014
A SURFACE LOW PRESSURE CENTER IS CURRENTLY RIDING JUST NORTH OF THE
OHIO RIVER VALLEY...LOCATED SOMEWHERE FAIRLY CLOSE TO INDIANAPOLIS.
AS THIS LOW CONTINUES TO PROGRESS ENEWARD...IT IS CURRENTLY PULLING
A WARM FRONT FROM SW TO NE ACROSS THE CWA /SHOULD BE THROUGH BY
AROUND 12Z/...AND THEN WILL FOLLOW UP WITH A COLD FRONT PASSING
THROUGH THE CWA FROM WEST TO EAST BETWEEN APPROX 10Z AND 15Z. WITH
EACH OF THESE SYSTEMS...WE ARE CONTINUING TO PICK UP LIGHT SHOWER
ACTIVITY...WITH SCATTERED TO WIDESPREAD RETURNS ACROSS PORTIONS OF
EASTERN KY IN RESPONSE TO THE WARM FRONT...AND ANOTHER AREA JUST
ALONG THE COLD FRONT ACROSS WEST CENTRAL KY. UNFORTUNATELY...MODELS
ARE STILL HAVING A HARD TIME SHOWING A WELL DEFINED PRECIP FORECAST
FOR THIS SYSTEM. LEANED ON A MIXTURE OF RADAR TRENDS...THE HRRR AND
RUC /WHICH SEEMED TO HAVE THE BEST HANDLE ON THE CURRENT
SITUATION/...AND SOME LESSER INFLUENCE FROM A BLEND OF OTHER HI RES
MODELS...TO COME UP WITH THE FORECAST FOR THE PROGRESSION OF THE RAIN
AS WE HEAD THROUGH TODAY. AS SUCH...THE CURRENT RAIN /AND ISOLATED
THUNDER/ OVER CENTRAL KY SHOULD MAKE IT INTO OUR WESTERN CWA WITHIN
THE NEXT FEW HOURS /AROUND 10 TO 11Z/...WHILE CHANCES WILL INCREASE
ALONG MUCH OF THE NE CWA AS THE LOW TRACKS JUST TO OUR NORTH.
DID CONTINUE TO NOTE THAT MOST OF THIS MOISTURE SHOWS UP AS BEING
FAIRLY SHALLOW IN THE FORECAST SOUNDINGS THROUGH TODAY...SO DON/T
EXPECT ANYTHING OTHER THAN LIGHT SHOWERS. ONCE DRY AIR MOVES IN
BEHIND THE COLD FRONT THIS AFTERNOON...EXPECT IT TO ONCE AGAIN TRAP
A LAYER OF LOW LEVEL MOISTURE NEAR THE SURFACE...WHERE IT WILL
LINGER THROUGH AROUND 15Z TOMORROW...LONG AFTER THE INFLUENCE OF THE
LOW PRESSURE SYSTEM. AS SUCH...WHILE SOME OF THIS MOISTURE WILL FALL
AS LIGHT RAIN DURING THE DAY TODAY...IT STANDS TO REASON THAT IT
COULD BE MIXED IN WITH DRIZZLE IN SOME LOCATIONS...AND THEN CHANGE
OVER TO ALL DRIZZLE TONIGHT AS MOISTURE BECOMES INCREASINGLY SHALLOW.
TRIED TO REFLECT THIS IN THE WEATHER GRIDS...WITH A MIXTURE OF
ISOLATED/SLIGHT CHANCE RAIN AND PATCHY DRIZZLE...THEN LIGHT DRIZZLE
LINGERING THROUGH TOMORROW MORNING.
TEMPS WILL RISE SOME THROUGHOUT THE MORNING...WITH SOME PLACES IN
THE EAST POSSIBLY PULLING OUT SOME LOW 50S DUE TO THE WAA BEHIND THE
WARM FRONT...BUT SHOULD GENERALLY FALL FROM WEST TO EAST DURING THE
AFTERNOON AS COLDER AIR FILTERS IN BEHIND THE COLD FRONTAL PASSAGE.
WINDS WILL ALSO CONTINUE TO BE GUSTY AHEAD AND JUST BEHIND THE
FRONT...DYING DOWN AS WE HEAD INTO THE EVENING HOURS. THE PUSH OF
COLDER AIR COULD ALLOW FOR SOME BELOW FREEZING TEMPS BY
OVERNIGHT...NAMELY IN THE HIGHEST TERRAIN IN THE SE. AS SUCH...SOME
FREEZING DRIZZLE IN THESE LOCATIONS CANNOT BE RULED OUT. DID GO AHEAD
AND KEEP A MENTION OF THIS IN THE GRIDS...BUT WILL NEED TO KEEP AN
EYE OUT AS WE HEAD INTO TONIGHT IN CASE ANY FURTHER ACTION NEEDS TO BE
TAKEN. HIGHS WEDNESDAY WILL FALL BELOW SEASONABLE NORMS ONCE
MORE...TOPPING OUT IN THE LOW 40S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 419 AM EST TUE DEC 16 2014
THE MODELS ARE IN GOOD AGREEMENT WITH A PROGRESSIVE LONG WAVE PATTERN
TO HOLD ON THROUGH THE END OF THE WEEK...FOLLOWED BY AMPLIFICATION
INTO EARLY NEXT WEEK. DETAILS WITHIN THE LONG WAVE PATTERN CONTINUE
TO BE CHALLENGING...SO HAVE STUCK FAIRLY CLOSE TO A BLEND OF THE
GUIDANCE...WHILE STEERING THE FORECAST TOWARDS GENERAL MODEL TRENDS
SEEN IN THE PAST FEW DAYS.
THE SOUTHERN STREAM WILL MAINLY BE PROVIDING OUR WEATHER THROUGH THE
PERIOD...AS TROUGHING ACROSS THE SOUTHWEST CONUS GRADUALLY
TRANSLATES EAST. INITIALLY...A DAMPENING SHORT WAVE TROUGH WILL EJECT
OUT OF THE MAIN TROUGH...AFFECTING OUR AREA VERY LATE WEDNESDAY NIGHT
INTO THURSDAY. FORCING WILL BE CONFINED TO THE MID AND UPPER
LEVELS...AND DEEPER MOISTURE CONTINUES TO BE LACKING ACROSS EASTERN
KENTUCKY. AS SUCH...WILL MAINTAIN A SLIGHT CHANCE OF SNOW/RAIN
GENERALLY NEAR AND SOUTH OF THE HAL ROGERS AND HIGHWAY 80 CORRIDORS.
THE MAIN TROUGH AXIS WILL THEN MOVE ACROSS THE GULF COAST STATES AND
EVENTUALLY SWING ACROSS THE SOUTHERN APPALACHIANS BY THE WEEKEND.
THE MODELS HAVE GENERALLY SHOWN A MORE SOUTHERLY TRACK WITH THE
ASSOCIATED SURFACE LOW. THE GFS HAS ALSO TRENDED NOTICEABLY SLOWER
WITH THE PRECIPITATION ONSET. THE THERMAL PROFILES CONTINUE TO DIFFER
QUITE A BIT...WITH THE ECMWF COOLER AND THE GFS WARMER. AS
SUCH...HAVE MAINTAINED A BROAD BRUSH WITH THE RAIN/SNOW POTENTIAL
UNTIL CONFIDENCE INCREASES. PRECIPITATION WILL BEGIN FRIDAY
NIGHT...WITH THE OVERALL BEST CHANCE FOR THE ENTIRE AREA ON SATURDAY.
PRECIPITATION WILL THEN TAPER OFF QUICKLY SATURDAY NIGHT...WITH ONLY
A SMALL CHANCE OF A FEW LINGERING SHOWERS IN THE FAR SOUTHEAST
THROUGH SUNDAY MORNING WITH UPSLOPE FLOW IN PLACE. HIGH PRESSURE WILL
THEN TAKE HOLD INTO EARLY NEXT WEEK...BEFORE A DEEPER TROUGH
APPROACHES FROM THE WEST.
BELOW NORMAL TEMPERATURES WILL REIGN THROUGH THE PERIOD. STUCK FAIRLY
CLOSE TO THE BLENDED GUIDANCE GIVEN THE UNCERTAINTY...HOWEVER DID
ALLOW FOR A MORE DIURNALLY LIMITED TEMPERATURE REGIME DURING THE
PERIODS OF GREATER PRECIPITATION CHANCES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 700 AM EST TUE DEC 16 2014
AFTER SHOWERS MOVED THROUGH IN RESPONSE TO A PASSING WARM FRONT...A
COLD FRONT IS NOW ABOUT TO TRAVERSE EASTERN KY DURING THE COURSE OF
THE MORNING. THIS WILL BRING ANOTHER ROUND OF SHOWERS TO PORTIONS OF
EASTERN KY. BASED ON LATEST RADAR TRENDS...IT SEEMS AS THOUGH THE
BEST OF THESE SHOWERS SHOULD STAY NORTH OF THE MOUNTAIN PARKWAY.
FORECAST SOUNDINGS ARE STILL POINTING AT A STRONG SUBSIDENCE
INVERSION SETTING UP BEHIND THE FRONT...WITH LOW LEVEL MOISTURE
BECOMING TRAPPED THROUGH THE TAF PERIOD. THIS WILL LEAD TO LOWERING
CIGS AND THE POTENTIAL FOR DRIZZLE THROUGH TOMORROW MORNING. FUEL
ALTERNATES ARE CONTINUING TO LOOK MORE LIKELY AS WE HEAD INTO THE
OVERNIGHT HOURS. ANOTHER CONCERN WILL BE THE WINDS. EXPECT WINDS AT
THE SURFACE TO INCREASE AGAIN ALONG AND JUST BEHIND THE COLD
FRONT...WITH GUSTS BETWEEN 15 AND 20KTS POSSIBLE THROUGH THE
AFTERNOON. WESTERLY WINDS WILL ALSO SIGNIFICANTLY INCREASE ALOFT AS A
JET STREAK PASSES ALONG AND SOUTH OF THE OHIO RIVER VALLEY DURING
MUCH OF THE TAF PERIOD. THE OVERNIGHT SUBSIDENCE INVERSION SHOULD AT
LEAST ALLOW WINDS IN THE LOW LEVELS TO DIE DOWN.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...JMW
LONG TERM...GEOGERIAN
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
700 AM EST TUE DEC 16 2014
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 351 AM EST TUE DEC 16 2014
A SURFACE LOW PRESSURE CENTER IS CURRENTLY RIDING JUST NORTH OF THE
OHIO RIVER VALLEY...LOCATED SOMEWHERE FAIRLY CLOSE TO INDIANAPOLIS.
AS THIS LOW CONTINUES TO PROGRESS ENEWARD...IT IS CURRENTLY PULLING
A WARM FRONT FROM SW TO NE ACROSS THE CWA /SHOULD BE THROUGH BY
AROUND 12Z/...AND THEN WILL FOLLOW UP WITH A COLD FRONT PASSING
THROUGH THE CWA FROM WEST TO EAST BETWEEN APPROX 10Z AND 15Z. WITH
EACH OF THESE SYSTEMS...WE ARE CONTINUING TO PICK UP LIGHT SHOWER
ACTIVITY...WITH SCATTERED TO WIDESPREAD RETURNS ACROSS PORTIONS OF
EASTERN KY IN RESPONSE TO THE WARM FRONT...AND ANOTHER AREA JUST
ALONG THE COLD FRONT ACROSS WEST CENTRAL KY. UNFORTUNATELY...MODELS
ARE STILL HAVING A HARD TIME SHOWING A WELL DEFINED PRECIP FORECAST
FOR THIS SYSTEM. LEANED ON A MIXTURE OF RADAR TRENDS...THE HRRR AND
RUC /WHICH SEEMED TO HAVE THE BEST HANDLE ON THE CURRENT
SITUATION/...AND SOME LESSER INFLUENCE FROM A BLEND OF OTHER HI RES
MODELS...TO COME UP WITH THE FORECAST FOR THE PROGRESSION OF THE RAIN
AS WE HEAD THROUGH TODAY. AS SUCH...THE CURRENT RAIN /AND ISOLATED
THUNDER/ OVER CENTRAL KY SHOULD MAKE IT INTO OUR WESTERN CWA WITHIN
THE NEXT FEW HOURS /AROUND 10 TO 11Z/...WHILE CHANCES WILL INCREASE
ALONG MUCH OF THE NE CWA AS THE LOW TRACKS JUST TO OUR NORTH.
DID CONTINUE TO NOTE THAT MOST OF THIS MOISTURE SHOWS UP AS BEING
FAIRLY SHALLOW IN THE FORECAST SOUNDINGS THROUGH TODAY...SO DON/T
EXPECT ANYTHING OTHER THAN LIGHT SHOWERS. ONCE DRY AIR MOVES IN
BEHIND THE COLD FRONT THIS AFTERNOON...EXPECT IT TO ONCE AGAIN TRAP
A LAYER OF LOW LEVEL MOISTURE NEAR THE SURFACE...WHERE IT WILL
LINGER THROUGH AROUND 15Z TOMORROW...LONG AFTER THE INFLUENCE OF THE
LOW PRESSURE SYSTEM. AS SUCH...WHILE SOME OF THIS MOISTURE WILL FALL
AS LIGHT RAIN DURING THE DAY TODAY...IT STANDS TO REASON THAT IT
COULD BE MIXED IN WITH DRIZZLE IN SOME LOCATIONS...AND THEN CHANGE
OVER TO ALL DRIZZLE TONIGHT AS MOISTURE BECOMES INCREASINGLY SHALLOW.
TRIED TO REFLECT THIS IN THE WEATHER GRIDS...WITH A MIXTURE OF
ISOLATED/SLIGHT CHANCE RAIN AND PATCHY DRIZZLE...THEN LIGHT DRIZZLE
LINGERING THROUGH TOMORROW MORNING.
TEMPS WILL RISE SOME THROUGHOUT THE MORNING...WITH SOME PLACES IN
THE EAST POSSIBLY PULLING OUT SOME LOW 50S DUE TO THE WAA BEHIND THE
WARM FRONT...BUT SHOULD GENERALLY FALL FROM WEST TO EAST DURING THE
AFTERNOON AS COLDER AIR FILTERS IN BEHIND THE COLD FRONTAL PASSAGE.
WINDS WILL ALSO CONTINUE TO BE GUSTY AHEAD AND JUST BEHIND THE
FRONT...DYING DOWN AS WE HEAD INTO THE EVENING HOURS. THE PUSH OF
COLDER AIR COULD ALLOW FOR SOME BELOW FREEZING TEMPS BY
OVERNIGHT...NAMELY IN THE HIGHEST TERRAIN IN THE SE. AS SUCH...SOME
FREEZING DRIZZLE IN THESE LOCATIONS CANNOT BE RULED OUT. DID GO AHEAD
AND KEEP A MENTION OF THIS IN THE GRIDS...BUT WILL NEED TO KEEP AN
EYE OUT AS WE HEAD INTO TONIGHT IN CASE ANY FURTHER ACTION NEEDS TO BE
TAKEN. HIGHS WEDNESDAY WILL FALL BELOW SEASONABLE NORMS ONCE
MORE...TOPPING OUT IN THE LOW 40S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 419 AM EST TUE DEC 16 2014
THE MODELS ARE IN GOOD AGREEMENT WITH A PROGRESSIVE LONG WAVE PATTERN
TO HOLD ON THROUGH THE END OF THE WEEK...FOLLOWED BY AMPLIFICATION
INTO EARLY NEXT WEEK. DETAILS WITHIN THE LONG WAVE PATTERN CONTINUE
TO BE CHALLENGING...SO HAVE STUCK FAIRLY CLOSE TO A BLEND OF THE
GUIDANCE...WHILE STEERING THE FORECAST TOWARDS GENERAL MODEL TRENDS
SEEN IN THE PAST FEW DAYS.
THE SOUTHERN STREAM WILL MAINLY BE PROVIDING OUR WEATHER THROUGH THE
PERIOD...AS TROUGHING ACROSS THE SOUTHWEST CONUS GRADUALLY
TRANSLATES EAST. INITIALLY...A DAMPENING SHORT WAVE TROUGH WILL EJECT
OUT OF THE MAIN TROUGH...AFFECTING OUR AREA VERY LATE WEDNESDAY NIGHT
INTO THURSDAY. FORCING WILL BE CONFINED TO THE MID AND UPPER
LEVELS...AND DEEPER MOISTURE CONTINUES TO BE LACKING ACROSS EASTERN
KENTUCKY. AS SUCH...WILL MAINTAIN A SLIGHT CHANCE OF SNOW/RAIN
GENERALLY NEAR AND SOUTH OF THE HAL ROGERS AND HIGHWAY 80 CORRIDORS.
THE MAIN TROUGH AXIS WILL THEN MOVE ACROSS THE GULF COAST STATES AND
EVENTUALLY SWING ACROSS THE SOUTHERN APPALACHIANS BY THE WEEKEND.
THE MODELS HAVE GENERALLY SHOWN A MORE SOUTHERLY TRACK WITH THE
ASSOCIATED SURFACE LOW. THE GFS HAS ALSO TRENDED NOTICEABLY SLOWER
WITH THE PRECIPITATION ONSET. THE THERMAL PROFILES CONTINUE TO DIFFER
QUITE A BIT...WITH THE ECMWF COOLER AND THE GFS WARMER. AS
SUCH...HAVE MAINTAINED A BROAD BRUSH WITH THE RAIN/SNOW POTENTIAL
UNTIL CONFIDENCE INCREASES. PRECIPITATION WILL BEGIN FRIDAY
NIGHT...WITH THE OVERALL BEST CHANCE FOR THE ENTIRE AREA ON SATURDAY.
PRECIPITATION WILL THEN TAPER OFF QUICKLY SATURDAY NIGHT...WITH ONLY
A SMALL CHANCE OF A FEW LINGERING SHOWERS IN THE FAR SOUTHEAST
THROUGH SUNDAY MORNING WITH UPSLOPE FLOW IN PLACE. HIGH PRESSURE WILL
THEN TAKE HOLD INTO EARLY NEXT WEEK...BEFORE A DEEPER TROUGH
APPROACHES FROM THE WEST.
BELOW NORMAL TEMPERATURES WILL REIGN THROUGH THE PERIOD. STUCK FAIRLY
CLOSE TO THE BLENDED GUIDANCE GIVEN THE UNCERTAINTY...HOWEVER DID
ALLOW FOR A MORE DIURNALLY LIMITED TEMPERATURE REGIME DURING THE
PERIODS OF GREATER PRECIPITATION CHANCES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 700 AM EST TUE DEC 16 2014
AFTER SHOWERS MOVED THROUGH IN RESPONSE TO A PASSING WARM FRONT...A
COLD FRONT IS NOW ABOUT TO TRAVERSE EASTERN KY DURING THE COURSE OF
THE MORNING. THIS WILL BRING ANOTHER ROUND OF SHOWERS TO PORTIONS OF
EASTERN KY. BASED ON LATEST RADAR TRENDS...IT SEEMS AS THOUGH THE
BEST OF THESE SHOWERS SHOULD STAY NORTH OF THE MOUNTAIN PARKWAY.
FORECAST SOUNDINGS ARE STILL POINTING AT A STRONG SUBSIDENCE
INVERSION SETTING UP BEHIND THE FRONT...WITH LOW LEVEL MOISTURE
BECOMING TRAPPED THROUGH THE TAF PERIOD. THIS WILL LEAD TO LOWERING
CIGS AND THE POTENTIAL FOR DRIZZLE THROUGH TOMORROW MORNING. FUEL
ALTERNATES ARE CONTINUING TO LOOK MORE LIKELY AS WE HEAD INTO THE
OVERNIGHT HOURS. ANOTHER CONCERN WILL BE THE WINDS. EXPECT WINDS AT
THE SURFACE TO INCREASE AGAIN ALONG AND JUST BEHIND THE COLD
FRONT...WITH GUSTS BETWEEN 15 AND 20KTS POSSIBLE THROUGH THE
AFTERNOON. WESTERLY WINDS WILL ALSO SIGNIFICANTLY INCREASE ALOFT AS A
JET STREAK PASSES ALONG AND SOUTH OF THE OHIO RIVER VALLEY DURING
MUCH OF THE TAF PERIOD. THE OVERNIGHT SUBSIDENCE INVERSION SHOULD AT
LEAST ALLOW WINDS IN THE LOW LEVELS TO DIE DOWN.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JMW
LONG TERM...GEOGERIAN
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
419 AM EST TUE DEC 16 2014
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 351 AM EST TUE DEC 16 2014
A SURFACE LOW PRESSURE CENTER IS CURRENTLY RIDING JUST NORTH OF THE
OHIO RIVER VALLEY...LOCATED SOMEWHERE FAIRLY CLOSE TO INDIANAPOLIS.
AS THIS LOW CONTINUES TO PROGRESS ENEWARD...IT IS CURRENTLY PULLING
A WARM FRONT FROM SW TO NE ACROSS THE CWA /SHOULD BE THROUGH BY
AROUND 12Z/...AND THEN WILL FOLLOW UP WITH A COLD FRONT PASSING
THROUGH THE CWA FROM WEST TO EAST BETWEEN APPROX 10Z AND 15Z. WITH
EACH OF THESE SYSTEMS...WE ARE CONTINUING TO PICK UP LIGHT SHOWER
ACTIVITY...WITH SCATTERED TO WIDESPREAD RETURNS ACROSS PORTIONS OF
EASTERN KY IN RESPONSE TO THE WARM FRONT...AND ANOTHER AREA JUST
ALONG THE COLD FRONT ACROSS WEST CENTRAL KY. UNFORTUNATELY...MODELS
ARE STILL HAVING A HARD TIME SHOWING A WELL DEFINED PRECIP FORECAST
FOR THIS SYSTEM. LEANED ON A MIXTURE OF RADAR TRENDS...THE HRRR AND
RUC /WHICH SEEMED TO HAVE THE BEST HANDLE ON THE CURRENT
SITUATION/...AND SOME LESSER INFLUENCE FROM A BLEND OF OTHER HI RES
MODELS...TO COME UP WITH THE FORECAST FOR THE PROGRESSION OF THE RAIN
AS WE HEAD THROUGH TODAY. AS SUCH...THE CURRENT RAIN /AND ISOLATED
THUNDER/ OVER CENTRAL KY SHOULD MAKE IT INTO OUR WESTERN CWA WITHIN
THE NEXT FEW HOURS /AROUND 10 TO 11Z/...WHILE CHANCES WILL INCREASE
ALONG MUCH OF THE NE CWA AS THE LOW TRACKS JUST TO OUR NORTH.
DID CONTINUE TO NOTE THAT MOST OF THIS MOISTURE SHOWS UP AS BEING
FAIRLY SHALLOW IN THE FORECAST SOUNDINGS THROUGH TODAY...SO DON/T
EXPECT ANYTHING OTHER THAN LIGHT SHOWERS. ONCE DRY AIR MOVES IN
BEHIND THE COLD FRONT THIS AFTERNOON...EXPECT IT TO ONCE AGAIN TRAP
A LAYER OF LOW LEVEL MOISTURE NEAR THE SURFACE...WHERE IT WILL
LINGER THROUGH AROUND 15Z TOMORROW...LONG AFTER THE INFLUENCE OF THE
LOW PRESSURE SYSTEM. AS SUCH...WHILE SOME OF THIS MOISTURE WILL FALL
AS LIGHT RAIN DURING THE DAY TODAY...IT STANDS TO REASON THAT IT
COULD BE MIXED IN WITH DRIZZLE IN SOME LOCATIONS...AND THEN CHANGE
OVER TO ALL DRIZZLE TONIGHT AS MOISTURE BECOMES INCREASINGLY SHALLOW.
TRIED TO REFLECT THIS IN THE WEATHER GRIDS...WITH A MIXTURE OF
ISOLATED/SLIGHT CHANCE RAIN AND PATCHY DRIZZLE...THEN LIGHT DRIZZLE
LINGERING THROUGH TOMORROW MORNING.
TEMPS WILL RISE SOME THROUGHOUT THE MORNING...WITH SOME PLACES IN
THE EAST POSSIBLY PULLING OUT SOME LOW 50S DUE TO THE WAA BEHIND THE
WARM FRONT...BUT SHOULD GENERALLY FALL FROM WEST TO EAST DURING THE
AFTERNOON AS COLDER AIR FILTERS IN BEHIND THE COLD FRONTAL PASSAGE.
WINDS WILL ALSO CONTINUE TO BE GUSTY AHEAD AND JUST BEHIND THE
FRONT...DYING DOWN AS WE HEAD INTO THE EVENING HOURS. THE PUSH OF
COLDER AIR COULD ALLOW FOR SOME BELOW FREEZING TEMPS BY
OVERNIGHT...NAMELY IN THE HIGHEST TERRAIN IN THE SE. AS SUCH...SOME
FREEZING DRIZZLE IN THESE LOCATIONS CANNOT BE RULED OUT. DID GO AHEAD
AND KEEP A MENTION OF THIS IN THE GRIDS...BUT WILL NEED TO KEEP AN
EYE OUT AS WE HEAD INTO TONIGHT IN CASE ANY FURTHER ACTION NEEDS TO BE
TAKEN. HIGHS WEDNESDAY WILL FALL BELOW SEASONABLE NORMS ONCE
MORE...TOPPING OUT IN THE LOW 40S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 419 AM EST TUE DEC 16 2014
THE MODELS ARE IN GOOD AGREEMENT WITH A PROGRESSIVE LONG WAVE PATTERN
TO HOLD ON THROUGH THE END OF THE WEEK...FOLLOWED BY AMPLIFICATION
INTO EARLY NEXT WEEK. DETAILS WITHIN THE LONG WAVE PATTERN CONTINUE
TO BE CHALLENGING...SO HAVE STUCK FAIRLY CLOSE TO A BLEND OF THE
GUIDANCE...WHILE STEERING THE FORECAST TOWARDS GENERAL MODEL TRENDS
SEEN IN THE PAST FEW DAYS.
THE SOUTHERN STREAM WILL MAINLY BE PROVIDING OUR WEATHER THROUGH THE
PERIOD...AS TROUGHING ACROSS THE SOUTHWEST CONUS GRADUALLY
TRANSLATES EAST. INITIALLY...A DAMPENING SHORT WAVE TROUGH WILL EJECT
OUT OF THE MAIN TROUGH...AFFECTING OUR AREA VERY LATE WEDNESDAY NIGHT
INTO THURSDAY. FORCING WILL BE CONFINED TO THE MID AND UPPER
LEVELS...AND DEEPER MOISTURE CONTINUES TO BE LACKING ACROSS EASTERN
KENTUCKY. AS SUCH...WILL MAINTAIN A SLIGHT CHANCE OF SNOW/RAIN
GENERALLY NEAR AND SOUTH OF THE HAL ROGERS AND HIGHWAY 80 CORRIDORS.
THE MAIN TROUGH AXIS WILL THEN MOVE ACROSS THE GULF COAST STATES AND
EVENTUALLY SWING ACROSS THE SOUTHERN APPALACHIANS BY THE WEEKEND.
THE MODELS HAVE GENERALLY SHOWN A MORE SOUTHERLY TRACK WITH THE
ASSOCIATED SURFACE LOW. THE GFS HAS ALSO TRENDED NOTICEABLY SLOWER
WITH THE PRECIPITATION ONSET. THE THERMAL PROFILES CONTINUE TO DIFFER
QUITE A BIT...WITH THE ECMWF COOLER AND THE GFS WARMER. AS
SUCH...HAVE MAINTAINED A BROAD BRUSH WITH THE RAIN/SNOW POTENTIAL
UNTIL CONFIDENCE INCREASES. PRECIPITATION WILL BEGIN FRIDAY
NIGHT...WITH THE OVERALL BEST CHANCE FOR THE ENTIRE AREA ON SATURDAY.
PRECIPITATION WILL THEN TAPER OFF QUICKLY SATURDAY NIGHT...WITH ONLY
A SMALL CHANCE OF A FEW LINGERING SHOWERS IN THE FAR SOUTHEAST
THROUGH SUNDAY MORNING WITH UPSLOPE FLOW IN PLACE. HIGH PRESSURE WILL
THEN TAKE HOLD INTO EARLY NEXT WEEK...BEFORE A DEEPER TROUGH
APPROACHES FROM THE WEST.
BELOW NORMAL TEMPERATURES WILL REIGN THROUGH THE PERIOD. STUCK FAIRLY
CLOSE TO THE BLENDED GUIDANCE GIVEN THE UNCERTAINTY...HOWEVER DID
ALLOW FOR A MORE DIURNALLY LIMITED TEMPERATURE REGIME DURING THE
PERIODS OF GREATER PRECIPITATION CHANCES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 102 AM EST TUE DEC 16 2014
A COMBINATION WARM FRONT AND COLD FRONT IS CURRENTLY MOVING THROUGH
KY...WITH THE WARM FRONT MAKING A SW TO NE PASS ACROSS EASTERN
KY...AND THE COLD FRONT NOW LOCATED OVER CENTRAL KY. LIGHT RAIN
SHOWERS ARE ONGOING AT MOST OF THE TAF SITES AS A RESULT OF THE
PASSING WARM FRONT. LATEST RADAR TRENDS ARE SHOWING A BRIEF BREAK
BEFORE THE NEXT ROUND OF SHOWERS ASSOCIATED WITH THE COLD FRONT MOVE
INTO THE AREA LATE TONIGHT. WINDS ARE REALLY PICKING UP AHEAD OF THE
COLD FRONT...SO WENT AHEAD AND INCLUDED GUSTY SOUTHERLY WINDS THROUGH
THE FIRST PART OF THE NIGHT...BECOMING MORE WESTERLY BEHIND THE FRONT
AND CONTINUING TO GUST INTO THE DAY TOMORROW. EXPECT CIGS TO CONTINUE
TO FALL TO MVFR...AND THEN EVENTUALLY INTO THE FUEL ALTERNATE
CATEGORY BY LATE TONIGHT. ONCE SHOWERS TAPER OFF BEHIND THE COLD
FRONT TOMORROW...FORECAST SOUNDINGS ARE STILL SUPPORTING THE IDEA FOR
DRIZZLE HANGING AROUND THROUGH TOMORROW NIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JMW
LONG TERM...GEOGERIAN
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
352 AM EST TUE DEC 16 2014
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 351 AM EST TUE DEC 16 2014
A SURFACE LOW PRESSURE CENTER IS CURRENTLY RIDING JUST NORTH OF THE
OHIO RIVER VALLEY...LOCATED SOMEWHERE FAIRLY CLOSE TO INDIANAPOLIS.
AS THIS LOW CONTINUES TO PROGRESS ENEWARD...IT IS CURRENTLY PULLING
A WARM FRONT FROM SW TO NE ACROSS THE CWA /SHOULD BE THROUGH BY
AROUND 12Z/...AND THEN WILL FOLLOW UP WITH A COLD FRONT PASSING
THROUGH THE CWA FROM WEST TO EAST BETWEEN APPROX 10Z AND 15Z. WITH
EACH OF THESE SYSTEMS...WE ARE CONTINUING TO PICK UP LIGHT SHOWER
ACTIVITY...WITH SCATTERED TO WIDESPREAD RETURNS ACROSS PORTIONS OF
EASTERN KY IN RESPONSE TO THE WARM FRONT...AND ANOTHER AREA JUST
ALONG THE COLD FRONT ACROSS WEST CENTRAL KY. UNFORTUNATELY...MODELS
ARE STILL HAVING A HARD TIME SHOWING A WELL DEFINED PRECIP FORECAST
FOR THIS SYSTEM. LEANED ON A MIXTURE OF RADAR TRENDS...THE HRRR AND
RUC /WHICH SEEMED TO HAVE THE BEST HANDLE ON THE CURRENT
SITUATION/...AND SOME LESSER INFLUENCE FROM A BLEND OF OTHER HI RES
MODELS...TO COME UP WITH THE FORECAST FOR THE PROGRESSION OF THE RAIN
AS WE HEAD THROUGH TODAY. AS SUCH...THE CURRENT RAIN /AND ISOLATED
THUNDER/ OVER CENTRAL KY SHOULD MAKE IT INTO OUR WESTERN CWA WITHIN
THE NEXT FEW HOURS /AROUND 10 TO 11Z/...WHILE CHANCES WILL INCREASE
ALONG MUCH OF THE NE CWA AS THE LOW TRACKS JUST TO OUR NORTH.
DID CONTINUE TO NOTE THAT MOST OF THIS MOISTURE SHOWS UP AS BEING
FAIRLY SHALLOW IN THE FORECAST SOUNDINGS THROUGH TODAY...SO DON/T
EXPECT ANYTHING OTHER THAN LIGHT SHOWERS. ONCE DRY AIR MOVES IN
BEHIND THE COLD FRONT THIS AFTERNOON...EXPECT IT TO ONCE AGAIN TRAP
A LAYER OF LOW LEVEL MOISTURE NEAR THE SURFACE...WHERE IT WILL
LINGER THROUGH AROUND 15Z TOMORROW...LONG AFTER THE INFLUENCE OF THE
LOW PRESSURE SYSTEM. AS SUCH...WHILE SOME OF THIS MOISTURE WILL FALL
AS LIGHT RAIN DURING THE DAY TODAY...IT STANDS TO REASON THAT IT
COULD BE MIXED IN WITH DRIZZLE IN SOME LOCATIONS...AND THEN CHANGE
OVER TO ALL DRIZZLE TONIGHT AS MOISTURE BECOMES INCREASINGLY SHALLOW.
TRIED TO REFLECT THIS IN THE WEATHER GRIDS...WITH A MIXTURE OF
ISOLATED/SLIGHT CHANCE RAIN AND PATCHY DRIZZLE...THEN LIGHT DRIZZLE
LINGERING THROUGH TOMORROW MORNING.
TEMPS WILL RISE SOME THROUGHOUT THE MORNING...WITH SOME PLACES IN
THE EAST POSSIBLY PULLING OUT SOME LOW 50S DUE TO THE WAA BEHIND THE
WARM FRONT...BUT SHOULD GENERALLY FALL FROM WEST TO EAST DURING THE
AFTERNOON AS COLDER AIR FILTERS IN BEHIND THE COLD FRONTAL PASSAGE.
WINDS WILL ALSO CONTINUE TO BE GUSTY AHEAD AND JUST BEHIND THE
FRONT...DYING DOWN AS WE HEAD INTO THE EVENING HOURS. THE PUSH OF
COLDER AIR COULD ALLOW FOR SOME BELOW FREEZING TEMPS BY
OVERNIGHT...NAMELY IN THE HIGHEST TERRAIN IN THE SE. AS SUCH...SOME
FREEZING DRIZZLE IN THESE LOCATIONS CANNOT BE RULED OUT. DID GO AHEAD
AND KEEP A MENTION OF THIS IN THE GRIDS...BUT WILL NEED TO KEEP AN
EYE OUT AS WE HEAD INTO TONIGHT IN CASE ANY FURTHER ACTION NEED TO BE
TAKEN. HIGHS WEDNESDAY WILL FALL BELOW SEASONABLE NORMS ONCE
MORE...TOPPING OUT IN THE LOW 40S.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 426 PM EST MON DEC 15 2014
RESIDUAL MOISTURE IN NW FLOW COLD AIR ADVECTION WILL BRING CLOUDS AS
THE PERIOD STARTS...WITH SOME LINGERING DRIZZLE POSSIBLE FOR MUCH OF
THE AREA. THERE IS SOME POTENTIAL FOR FREEZING DRIZZLE AT HIGHER
ELEVATIONS IN THE SE PART OF THE STATE. ANY DRIZZLE WILL END AND
CLOUDS SHOULD BREAK UP DURING THE DAY AS SURFACE RIDGING BUILDS IN
FROM THE WEST.
THE RETURN TO FAIR WEATHER COULD BE SHORT-LIVED. MOISTURE OFF THE
GULF WILL BE ISENTROPICALLY LIFTED OVER THE SOUTHERN PLAINS AND GET
CAUGHT IN THE MID/UPPER LEVEL FLOW WITH A WEAK SOUTHERN STREAM
IMPULSE MOVING THROUGH. 12Z MODEL BLEND SUGGESTS LOW POPS FOR LIGHT
PRECIP WITH THIS SYSTEM IN OUR SOUTHERN COUNTIES ON THURSDAY.
TEMPERATURES LOOK MARGINAL FOR RAIN/SNOW AND HAVE INCLUDED BOTH.
ONCE THE THURSDAY SYSTEM LEAVES...THERE IS ANOTHER BREAK FOR ABOUT 24
HOURS BEFORE THE NEXT ONE HAS TO BE DEALT WITH. A MID/UPPER LEVEL
TROUGH CURRENTLY OFFSHORE OF THE WEST COAST WILL MOVE INLAND AND
TRACK ACROSS THE SOUTHWEST CONUS. AS IT EMERGES OVER THE SOUTHERN
PLAINS...SURFACE LOW PRESSURE SHOULD DEVELOP ALONG THE WESTERN GULF
COAST. AS THIS SYSTEM HEADS EAST...ITS EVENTUAL EVOLUTION WILL
DETERMINE OUR WEEKEND WEATHER. MODELS STILL HAVE NOT COME TO A GOOD
CONSENSUS ON WHAT WILL HAPPEN. THE LATEST TREND IN THE 12Z RUNS IS FOR
A TRACK FURTHER SOUTH AND LIGHTER PRECIP IN OUR AREA. CONSIDERING HOW
POORLY THEY HAVE BEEN HANDLING IT SO FAR...IT WOULD BE GOOD TO SEE AT
LEAST ANOTHER FULL SET OF GUIDANCE BEFORE WHOLE-HEARTEDLY JUMPING ON
THAT BANDWAGON. HAVE MADE A MODEST DRAWBACK ON POPS...WHILE
MAINTAINING THE POTENTIAL FOR BOTH SNOW AND RAIN. GREATEST POPS ARE
LATE FRIDAY NIGHT INTO SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 102 AM EST TUE DEC 16 2014
A COMBINATION WARM FRONT AND COLD FRONT IS CURRENTLY MOVING THROUGH
KY...WITH THE WARM FRONT MAKING A SW TO NE PASS ACROSS EASTERN
KY...AND THE COLD FRONT NOW LOCATED OVER CENTRAL KY. LIGHT RAIN
SHOWERS ARE ONGOING AT MOST OF THE TAF SITES AS A RESULT OF THE
PASSING WARM FRONT. LATEST RADAR TRENDS ARE SHOWING A BRIEF BREAK
BEFORE THE NEXT ROUND OF SHOWERS ASSOCIATED WITH THE COLD FRONT MOVE
INTO THE AREA LATE TONIGHT. WINDS ARE REALLY PICKING UP AHEAD OF THE
COLD FRONT...SO WENT AHEAD AND INCLUDED GUSTY SOUTHERLY WINDS THROUGH
THE FIRST PART OF THE NIGHT...BECOMING MORE WESTERLY BEHIND THE FRONT
AND CONTINUING TO GUST INTO THE DAY TOMORROW. EXPECT CIGS TO CONTINUE
TO FALL TO MVFR...AND THEN EVENTUALLY INTO THE FUEL ALTERNATE
CATEGORY BY LATE TONIGHT. ONCE SHOWERS TAPER OFF BEHIND THE COLD
FRONT TOMORROW...FORECAST SOUNDINGS ARE STILL SUPPORTING THE IDEA FOR
DRIZZLE HANGING AROUND THROUGH TOMORROW NIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JMW
LONG TERM...HAL
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
1147 AM CST TUE DEC 16 2014
.AVIATION...
DRY AIR WILL RESULT IN VFR CONDITIONS WITH MOSTLY CLEAR SKIES AND
EXCELLENT VISIBILITIES THROUGH WEDNESDAY. NORTHWEST WINDS MAY
OCCASIONALLY GUST 15 TO 20 KNOTS THROUGH SUNSET TODAY...OTHERWISE
PREVAILING WINDS WILL BE MOSTLY 10 KNOTS OR LESS. 22/TD
&&
.PREV DISCUSSION... /ISSUED 345 AM CST TUE DEC 16 2014/
SHORT TERM...
COLD FRONT IS CURRENTLY LOCATED ALONG A GULFPORT TO HOUMA LINE AND
MOVING EASTWARD. THERE/S NOT A WHOLE LOT OF RAINFALL ALONG THE
BOUNDARY WITH LOCATIONS SEEING AT MOST ABOUT A QUARTER OF AN INCH
BUT MORE COMMONLY LESS THAN ONE TENTH. WINDS HAVE GUSTED TO AS HIGH
AS 30 KNOTS BUT THOSE CONDITIONS WILL BE QUITE BRIEF AND RIGHT ALONG
THE LINE OF SHOWERS. TEMPERATURES ARE GENERALLY DROPPING ABOUT 6
DEGREES AS THE FRONT PASSES BUT THE MORE SIGNIFICANT CHANGE IS
DEWPOINTS FALLING AROUND 10 DEGREES. THE HRRR QPF OUTPUT IS SPOT ON
FOR INITIATION AND HAS BEEN DOING WELL FOR THE LAST FEW HOURS. GOING
OFF THAT...WHATS LEFT OF THIS LINE OF SHOWERS MOVING THROUGH SHOULD
BE PUSHING OFFSHORE BY SUNRISE AND OUT OF THE ENTIRE CWA BY NOON.
TODAY/S HIGHS WILL BE A FIGHT BETWEEN INSOLATION AND COOL AIR MOVING
IN TODAY AS SURFACE HIGH PRESSURE BUILDS IN. TEMPERATURES WILL DROP
ABOUT 10 TO 15 DEGREES FROM MONDAY OR LOWER TO UPPER 60S WHICH IS
RIGHT ABOUT NORMAL FOR THIS TIME OF YEAR. MOVING INTO THE OVERNIGHT
HOURS...THE COMBINATION OF LIGHT WINDS AND CLEAR SKIES SHOULD ALLOW
FOR GOOD RADIATIONAL COOLING. AM AT OR SLIGHTLY BELOW GUIDANCE ON
FCST LOWS.
LONG TERM...
A BRIEF COOLING TREND WILL PERSIST ON WEDNESDAY AS HIGH PRESSURE
BUILDING IN FROM THE NORTH CONTINUES TO BRING IN COLDER AND DRIER
AIR. THIS WILL BRING HIGHS DOWN A FEW DEGREES MORE FROM TUESDAY TO
NEAR 60 ON WEDNESDAY. THIS COOL DOWN WILL BE BRIEF AS THE SFC RIDGE
QUICKLY SLIDES EAST AND SOUTHEASTERLY FLOW & MOISTURE BEGINS TO
RETURN.
THE NEXT EVENT TO IMPACT THE AREA COMES IN LATE THIS WEEK. MODELS
SHOW A WEAKER UPPER LEVEL TROUGH SWINGING ACROSS THE BAJA OF
CALIFORNIA ON WEDNESDAY. A WEAKER PORTION OF THIS TROUGH WILL SHOOT
NORTHEAST ACROSS THE CENTRAL PLAINS WEDNESDAY NIGHT. AN ASSOCIATED
CONVERGENCE ZONE WILL DEVELOP ACROSS EAST TEXAS AND NORTHERN
LOUISIANA AS A RESULT. A FEW SHOWERS ALONG THIS BOUNDARY COULD NUDGE
INTO THE NORTHWESTERN PORTIONS OF THE CWA THURSDAY. THE MAIN PIECE
OF THE UPPER TROUGH TO THE WEST WILL BEGIN PROGRESSING EAST ACROSS
NEW MEXICO AND TEXAS ON FRIDAY. AS SURFACE LOW WILL DEVELOP JUST
AHEAD OF THIS UPPER LOW AND TRACK ACROSS THE CWA FRIDAY INTO FRIDAY
NIGHT. THIS WILL BE THE MAIN FOCUS FOR SHOWERS AND POSSIBLY A FEW
THUNDERSTORMS. INSTABILITY DOES APPEAR TO BE HIGHER CLOSER TO THE
COAST AND THUS COASTAL PARISHES AND COUNTIES IS WHERE THE STRONGER
ACTIVITY WILL BE. DRYING WILL THEN TAKE PLACE SATURDAY...ESPECIALLY
IN THE AFTERNOON HOURS WITH MUCH COOLER CONDITIONS SATURDAY AND
SUNDAY. HIGHS WILL STRUGGLE TO REACH 60 ON SATURDAY AND EVEN LESS
LIKELY ON SUNDAY. LOWS WILL BE JUST AS COOL AS WELL WITH MINS IN THE
UPPER 30S TO MID 40S.
MEFFER
AVIATION...COLD FRONT AND ASSOCIATED LINE
SHRA HAVE ALREADY MOVED THROUGH THE MAJORITY OF THE TERMINALS AND
VFR CONDITIONS ARE SETTING RIGHT BACK IN. WINDS WILL REMAIN OUT OF
THE NW/NNW THROUGH TODAY BUT SHOULD QUICKLY RELAX AFTER 3Z
TONIGHT...IN FACT THE SOUTHSHORE TERMINALS WILL LIKELY SEE WINDS
DROP SIGNIFICANTLY TONIGHT EVEN AFTER A COLD FRONTAL PASSAGE. OTHER
THAN THAT EVERYTHING SHOULD REMAIN QUIET. /CAB/
MARINE...WINDS BEHIND THE COLD FRONT THIS MORNING WILL REMAIN
ELEVATED FOR A SHORT WHILE BUT EXPECT THEM TO DROP BELOW SCS
HEADLINE CRITERIA BEFORE MIDDAY. CAA IS JUST NOT THAT STRONG BEHIND
THE FRONT COMBINE THAT WITH THE ASSOCIATED SFC LOW BEING RATHER FAR
NORTH AND HIGH PRESSURE QUICKLY BUILDING BACK INTO THE REGION
OFFSHORE WINDS WILL LIKELY BE 10-15 KTS TONIGHT IN THE OUTER WATERS.
HIGH PRESSURE SHOULD KEEP THINGS RELATIVELY QUIET THROUGH THU NIGHT
AND THEN DEPENDING ON THE EVENTUAL TRACK OF THE NEXT SFC LOW ONSHORE
WINDS LOOK LIKE THEY SHOULD BEGIN TO RAMP BACK UP FRI WITH SCY
CONDITIONS POSSIBLE FRI THROUGH SAT. /CAB/
DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 62 34 58 42 / 0 0 0 10
BTR 64 37 61 44 / 0 0 0 10
ASD 66 35 61 42 / 10 0 0 0
MSY 65 44 60 48 / 10 0 0 0
GPT 65 38 59 44 / 10 0 0 0
PQL 69 35 61 39 / 20 0 0 0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
345 AM CST TUE DEC 16 2014
.SHORT TERM...
COLD FRONT IS CURRENTLY LOCATED ALONG A GULFPORT TO HOUMA LINE AND
MOVING EASTWARD. THERE/S NOT A WHOLE LOT OF RAINFALL ALONG THE
BOUNDARY WITH LOCATIONS SEEING AT MOST ABOUT A QUARTER OF AN INCH
BUT MORE COMMONLY LESS THAN ONE TENTH. WINDS HAVE GUSTED TO AS HIGH
AS 30 KNOTS BUT THOSE CONDITIONS WILL BE QUITE BRIEF AND RIGHT ALONG
THE LINE OF SHOWERS. TEMPERATURES ARE GENERALLY DROPPING ABOUT 6
DEGREES AS THE FRONT PASSES BUT THE MORE SIGNIFICANT CHANGE IS
DEWPOINTS FALLING AROUND 10 DEGREES. THE HRRR QPF OUTPUT IS SPOT ON
FOR INITIATION AND HAS BEEN DOING WELL FOR THE LAST FEW HOURS. GOING
OFF THAT...WHATS LEFT OF THIS LINE OF SHOWERS MOVING THROUGH SHOULD
BE PUSHING OFFSHORE BY SUNRISE AND OUT OF THE ENTIRE CWA BY NOON.
TODAY/S HIGHS WILL BE A FIGHT BETWEEN INSOLATION AND COOL AIR MOVING
IN TODAY AS SURFACE HIGH PRESSURE BUILDS IN. TEMPERATURES WILL DROP
ABOUT 10 TO 15 DEGREES FROM MONDAY OR LOWER TO UPPER 60S WHICH IS
RIGHT ABOUT NORMAL FOR THIS TIME OF YEAR. MOVING INTO THE OVERNIGHT
HOURS...THE COMBINATION OF LIGHT WINDS AND CLEAR SKIES SHOULD ALLOW
FOR GOOD RADIATIONAL COOLING. AM AT OR SLIGHTLY BELOW GUIDANCE ON
FCST LOWS.
.LONG TERM...
A BRIEF COOLING TREND WILL PERSIST ON WEDNESDAY AS HIGH PRESSURE
BUILDING IN FROM THE NORTH CONTINUES TO BRING IN COLDER AND DRIER
AIR. THIS WILL BRING HIGHS DOWN A FEW DEGREES MORE FROM TUESDAY TO
NEAR 60 ON WEDNESDAY. THIS COOL DOWN WILL BE BRIEF AS THE SFC RIDGE
QUICKLY SLIDES EAST AND SOUTHEASTERLY FLOW & MOISTURE BEGINS TO
RETURN.
THE NEXT EVENT TO IMPACT THE AREA COMES IN LATE THIS WEEK. MODELS
SHOW A WEAKER UPPER LEVEL TROUGH SWINGING ACROSS THE BAJA OF
CALIFORNIA ON WEDNESDAY. A WEAKER PORTION OF THIS TROUGH WILL SHOOT
NORTHEAST ACROSS THE CENTRAL PLAINS WEDNESDAY NIGHT. AN ASSOCIATED
CONVERGENCE ZONE WILL DEVELOP ACROSS EAST TEXAS AND NORTHERN
LOUISIANA AS A RESULT. A FEW SHOWERS ALONG THIS BOUNDARY COULD NUDGE
INTO THE NORTHWESTERN PORTIONS OF THE CWA THURSDAY. THE MAIN PIECE
OF THE UPPER TROUGH TO THE WEST WILL BEGIN PROGRESSING EAST ACROSS
NEW MEXICO AND TEXAS ON FRIDAY. AS SURFACE LOW WILL DEVELOP JUST
AHEAD OF THIS UPPER LOW AND TRACK ACROSS THE CWA FRIDAY INTO FRIDAY
NIGHT. THIS WILL BE THE MAIN FOCUS FOR SHOWERS AND POSSIBLY A FEW
THUNDERSTORMS. INSTABILITY DOES APPEAR TO BE HIGHER CLOSER TO THE
COAST AND THUS COASTAL PARISHES AND COUNTIES IS WHERE THE STRONGER
ACTIVITY WILL BE. DRYING WILL THEN TAKE PLACE SATURDAY...ESPECIALLY
IN THE AFTERNOON HOURS WITH MUCH COOLER CONDITIONS SATURDAY AND
SUNDAY. HIGHS WILL STRUGGLE TO REACH 60 ON SATURDAY AND EVEN LESS
LIKELY ON SUNDAY. LOWS WILL BE JUST AS COOL AS WELL WITH MINS IN THE
UPPER 30S TO MID 40S.
MEFFER
&&
.AVIATION...COLD FRONT AND ASSOCIATED LINE
SHRA HAVE ALREADY MOVED THROUGH THE MAJORITY OF THE TERMINALS AND
VFR CONDITIONS ARE SETTING RIGHT BACK IN. WINDS WILL REMAIN OUT OF
THE NW/NNW THROUGH TODAY BUT SHOULD QUICKLY RELAX AFTER 3Z
TONIGHT...IN FACT THE SOUTHSHORE TERMINALS WILL LIKELY SEE WINDS
DROP SIGNIFICANTLY TONIGHT EVEN AFTER A COLD FRONTAL PASSAGE. OTHER
THAN THAT EVERYTHING SHOULD REMAIN QUIET. /CAB/
&&
.MARINE...WINDS BEHIND THE COLD FRONT THIS MORNING WILL REMAIN
ELEVATED FOR A SHORT WHILE BUT EXPECT THEM TO DROP BELOW SCS
HEADLINE CRITERIA BEFORE MIDDAY. CAA IS JUST NOT THAT STRONG BEHIND
THE FRONT COMBINE THAT WITH THE ASSOCIATED SFC LOW BEING RATHER FAR
NORTH AND HIGH PRESSURE QUICKLY BUILDING BACK INTO THE REGION
OFFSHORE WINDS WILL LIKELY BE 10-15 KTS TONIGHT IN THE OUTER WATERS.
HIGH PRESSURE SHOULD KEEP THINGS RELATIVELY QUIET THROUGH THU NIGHT
AND THEN DEPENDING ON THE EVENTUAL TRACK OF THE NEXT SFC LOW ONSHORE
WINDS LOOK LIKE THEY SHOULD BEGIN TO RAMP BACK UP FRI WITH SCY
CONDITIONS POSSIBLE FRI THROUGH SAT. /CAB/
&&
.DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 62 34 58 42 / 0 0 0 10
BTR 64 37 61 44 / 0 0 0 10
ASD 66 35 61 42 / 10 0 0 0
MSY 65 44 60 48 / 10 0 0 0
GPT 65 38 59 44 / 10 0 0 0
PQL 69 35 61 39 / 20 0 0 0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
312 PM EST TUE DEC 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 536 AM EST TUE DEC 16 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A SRN STREAM SHRTWV/LOW OVER
NRN IL AND A NRN STREAM SHRTWV ACROSS NW ONTARIO INTO NW MN. AT THE
SFC...LOW PRES WAS LOCATED OVER NRN IL WITH A TROUGH TO THE NORTH
INTO ERN UPPER MI. 295K-300K ISENTROPIC LIFT AHEAD OF THE NRN IL LOW
HAS BROUGHT AN INCREASE IN PCPN COVERAGE/INTENSITY ACROSS CNTRL
UPPER MI WHILE 850-700 FGEN HAS SUPPORTED THE SNOW INTO WRN UPPER
MI. NRLY LOW LEVEL FLOW WITH THE TIGHTENING PRES GRADIENT BEHIND THE
TROUGH HAS BROUGHT COLDER AIR INTO WRN UPPER MI CHANGING THE RAIN TO
SNOW AT CMX/IWD/LNL. EVEN THROUGH TEMPS HAVE ALSO FALLEN BELOW 32F
AT KMQT...THE CIRCULATION AROUND THE SRN STREAM LOW HAS MAINTAINED
AN ELEVATED WARM LAYER (AROUND 850 MB FROM 1C TO 3C) OVER CENTRAL
UPPER MI. EVEN WITH AIR TEMPS FALLING BELOW FREEZING...THE RECENT
WARM CONDITIONS HAVE LIMITED GLAZE POTENTIAL AS MOST SURFACES HAVE
NOT COOLED OFF AS FAST.
TODAY...AS THE SRN STREAM SHRTWV LIFTS TO THE NW THE NRN STREAM
SHRTWV WILL BECOME THE DOMINANT FEATURE LATE TODAY INTO TONIGHT.
EXPECT THAT THE LINGERING WARM LAYER WILL SUPPORT A BRIEF PERIOD OF
LIGHT FREEZING RAIN OR SLEET THROUGH AROUND 14Z. THE BEST
CHANCE FOR ANY ICING WOULD BE OVER THE HIGHER TERRAIN WHERE TEMPS
HAVE ALREADY FALLEN OFF BELOW FREEZING. OTHERWISE...THE RAIN SNOW
CHANGE OVER IS EXPECTED TO MOVE INTO THE ERN CWA BY AFTERNOON WITH
ALL SNOW AT ERY AFTER 21Z. THE NRN STREAM SHRTWV WITH INCREASING
700-500 MB QVECTOR CONV WILL SUPPORT LIGHT TO MODERATE SNOW ACROSS
UPPER MI TODAY. 1 TO 4 INCH AMOUNTS ARE EXPECTED TODAY WITH HIGHEST
AMOUNTS OVER THE WEST HALF WHERE NRLY WINDS BRING ADDITIONAL LAKE
ENHANCEMENT AND UPSLOPE FLOW AS 850 MB TEMPS FALL INTO THE -6C TO
-10C RANGE.
TONIGHT...AS THE MID LEVEL LOW PIVOTS THROUGH NRN WI...LARGE SCALE
LIFT WILL PREVAIL ACROSS UPPER MI WITH CONTINUED LIGHT SNOWFALL
AMOUNTS. THE HEAVIER SNOWFAL WILL CONTINUE INTO THE NORTH NEAR LAKE
SUPERIOR WITH ADDITIONAL SNOWFALL TOTALS IN THE 3 TO 5 INCH RANGE.
HEADLINES...A WINTER WEATHER ADVISORY WAS ISSUED FOR THE NORTHERN
COUNTIES FOR THE MIXED PRECIPITATION THIS MORNING AND LONG DURATION
LIGHT TO MODERATE SNOW EVENT.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 312 PM EST TUE DEC 16 2014
BY 00Z THURSDAY THE MAIN 500MB LOW WILL BE POSITIONED OVER BY...WITH
THE TROUGH LINGERING AT THE SFC AND ALOFT ACROSS THE UPPER GREAT
LAKES. A SIZABLE RIDGE WILL BE SET UP ACROSS S CENTRAL CANADA.
850MB TEMPS HOVERING IN THE -6 TO -8C RANGE AND FAVORABLE NNE WINDS
WILL KEEP SOME LIGHT LAKE EFFECT SNOW SHOWERS LINGERING ACROSS N
CENTRAL UPPER MI WEDNESDAY NIGHT. NOT EXPECTING MUCH IN THE WAY OF
ACCUMULATIONS GIVEN THE BORDERLINE TEMPERATURES ALOFT...AND LIMITED
MOISTURE THAT LOOKS TO BE STUCK AT OR BELOW 900MB. THE DGZ IS STILL
WAY UP AROUND 600MB...IN CLEAR AIR. EXPECT LOW CLOUDS TO LINGER INTO
THURSDAY MORNING.
OTHERWISE DRY AIR WILL RETURN FOR THE ENTIRE CWA FOR THURSDAY
THROUGH SATURDAY NIGHT...WITH SFC HIGH PRESSURE SETTLING IN FROM THE
NW BEFORE SLOWLY EXITING TO SE CANADA AND THE NEW ENGLAND STATES
SATURDAY. THE 500MB HIGH WILL SHIFT ACROSS N ONTARIO ON THURSDAY AND
CENTRAL QUEBEC FRIDAY NIGHT. ON THE E SIDE OF THE HIGH A
SHORTWAVE/TROUGH WILL MOVE FROM THE QUEBEC/ONTARIO BORDER AT 18Z
THURSDAY TO FAR E UPPER MI OR FAR S ONTARIO AROUND DAYBREAK FRIDAY.
LITTLE MORE THAN ADDITIONAL CLOUD COVER IS EXPECTED. THE 16/00Z AND
12Z ECMWF WERE THE MOST AGGRESSIVE WITH THIS FEATURE...KEEPING IT
ACROSS FAR E UPPER MI INTO FRIDAY EVENING. 850MB TEMPS WILL LINGER
AROUND -6 TO -8C THROUGH SUNDAY...SO EXPECT SO HUGE SWINGS
TEMPERATURE WISE THROUGH THIS PERIOD.
A ELONGATED AND OVERALL WEAK TROUGH EXTENDING FROM CENTRAL CANADA
THROUGH THE S PLAINS STATES FRIDAY AFTERNOON WILL EDGE TOWARD THE
UPPER GREAT LAKES TO START OUT THE WEEKEND. WHILE SEVERAL SMALL
DISTURBANCES WILL NEAR THE AREA SATURDAY AFTERNOON...DRY WEATHER IS
STILL ANTICIPATED. THE NEXT GOOD CHANCE FOR WIDESPREAD PRECIP SHOULD
COME IN MONDAY INTO TUESDAY...AS THE THE NEXT SFC LOW OVER CENTRAL
CANADA AND THE N PLAINS MONDAY MORNING SHIFTS ACROSS MN MONDAY
NIGHT...AND ONTARIO/UPPER GREAT LAKES DURING THE DAY TUESDAY. AHEAD
OF THE LOW EXPECT WAA PRECIP. A CHANCE OF RAIN COULD CREEP INTO THE
E THIRD OF THE U.P. /MAINLY STAY ACROSS LAKE MI/.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1221 PM EST TUE DEC 16 2014
SNOW WILL CONTINUE AT ALL TAF SITES THROUGH THE FCST PERIOD WITH
IFR/LIFR CONDITIONS EXPECTED.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 552 AM EST TUE DEC 16 2014
A TIGHTENING PRES GRADIENT BETWEEN LOW PRES OVER NRN IL LIFTING TO
THE NE AND HIGH PRES OVER MANITOBA INTO THE NRN PLAINS WILL RESULT
IN NORTH WINDS OF 20 TO 30 KNOTS WITH A FEW GALE FORCE GUSTS TO 35
KNOTS TODAY INTO THIS EVENING. AS HIGH PRES BUILDS INTO THE NRN
LAKES FROM WED INTO THU...WINDS WILL DIMINISH TO 20 KNOTS OR LESS.
HIGH PRESSURE WILL THEN DOMINATE INTO THE WEEKEND WITH WINDS
REMAINING BELOW 20 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST WEDNESDAY FOR MIZ001-
003>006-084-085.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST
WEDNESDAY FOR MIZ007.
WINTER STORM WARNING UNTIL 7 PM EST /6 PM CST/ WEDNESDAY FOR
MIZ002-009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1231 PM EST TUE DEC 16 2014
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 321 AM EST TUE DEC 16 2014
LOW PRESSURE WILL MOVE ACROSS LOWER MICHIGAN TODAY SPREADING RAIN
SHOWERS AS IT GOES. COLDER AIR WILL WRAP INTO THE SYSTEM LATER THIS
EVENING AND THE RAIN WILL MIX WITH AND THEN CHANGE TO LIGHT SNOW.
THIS WILL BEGIN A PERIOD OF NEAR NORMAL TEMPERATURES...ALTHOUGH MUCH
COLDER THAN WHAT WE`VE SEEN LATELY...THAT WILL LAST THROUGH THE
WEEKEND. LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE WEDNESDAY INTO
THURSDAY WITH LIGHT ACCUMULATIONS POSSIBLE MAINLY WEST OF US-131.
&&
.UPDATE...
ISSUED AT 839 AM EST TUE DEC 16 2014
FOG HAS BECOME DENSE OVER A GOOD PART OF SOUTHWEST LOWER MICHIGAN.
LOOKING AT THE LATEST RAP MODEL DATA...THE LOWEST VISIBILITIES ARE
WHERE THE WINDS ARE CALM...WHICH IS UNDER THE SURFACE LOW. THIS
AREA OF CALM WINDS SHIFTS TO THE EAST NORTHEAST OVER TIME AND BY
16Z IS OVER OUR NORTHEAST CWA....REED CITY TO CLAIR TO NEAR ALMA.
AFTER THAT IT IS GONE. SO I BELIEVE THE FOG AREA WILL PERSIST A
GOOD PART OF THE MORNING BUT ANY ONE LOCATION SHOULD HAVE ONLY 2
TO 3 HOURS OF LOW VISIBILITIES. GIVEN THE SHORT TIME WINDOW FOR
THIS FOG I AS THINKING NOT TO ISSUE A FOG ADVISORY AT THIS POINT.
WE HAVE ALREADY ISSUED A SPECIAL WEATHER STATEMENT ON THE FOG AND
WE WILL CALL THAT GOOD FOR NOW.
OTHERWISE THE ON GOING FORECAST IS GOOD...SHOWERS WILL CONTINUE
THROUGH THE DAY AND CHANGE TO SNOW SHOWERS OVERNIGHT.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 321 AM EST TUE DEC 16 2014
FORECAST CONCERNS DEAL WITH THE EVOLUTION OF THE LOW CURRENTLY
MOVING THROUGH NORTHWEST ILLINOIS.
REGIONAL RADAR AND IR LOOP SHOWS A WELL DEFINED LOW JUST CROSSING
THE MISSISSIPPI. LIGHT RAIN SHOWERS CONTINUE TO PIVOT NORTHWARD FROM
INDIANA AND WE/LL BE LOOKING AT SHOWERS THROUGHOUT THE DAY AS THE
LOW MOVES ACROSS LOWER MICHIGAN. HEAVY RAIN ISN/T ANTICIPATED.
HOWEVER...THERE HAS BEEN SOME LIGHTNING OVER SOUTHERN INDIANA.
MODELS SHOW SOME ELEVATED INSTABILITY DEVELOPING OVER FAR WESTERN
LAKE ERIE THIS MORNING BUT IT PROBABLY TOO FAR AWAY TO RESULT IN
THUNDER IN OUR CWA.
COLDER AIR WILL WRAP INTO THE SYSTEM TONIGHT AND TURN THE LINGERING
PCPN TO LIGHT SNOW SHOWERS. H8 TEMPS FALL TO -12C WEDNESDAY AND THIS
NORMALLY CREATES SUFFICIENT OVER-LAKE INSTABILITY TO GENERATE SNOW
SHOWERS. THE ISSUE THIS TIME THOUGH IS THE SHALLOW MOISTURE. THE
DGZ IS VERY SMALL AND RESIDES AT THE TOP OF THE SHALLOW MOISTURE
AROUND 4K FT. IT/S PROBABLY ENOUGH TO SEE SOME SNOW SHOWERS...AND
LIGHT ACCUMS WEST OF US-131 BUT NOT MUCH MORE THAN THAT. THE SHSN
WILL GRADUALLY DIMINISH WEDNESDAY NIGHT.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 321 AM EST TUE DEC 16 2014
MORE QUIET WEATHER IS IN STORE IN THE LONG TERM PERIOD AS THE SPLIT
FLOW ALOFT CONTINUES AND SURFACE HIGH PRESSURE DOMINATES. THE POLAR
JET STAYS WELL TO OUR NORTH AND THE SRN STREAM BRANCH REMAINS
SOUTH... SO STILL NO MAJOR WINTER SYSTEMS OR ARCTIC AIR IN OUR
FUTURE.
THE MAIN CONCERN WILL BE CLOUD COVER AS STRATUS/FOG/DRIZZLE COULD BE
AN ISSUE AGAIN UNDER THE SFC HIGH. FOR NOW WILL BE OPTIMISTIC WITH
PARTLY SUNNY WORDING BUT THIS COULD CHANGE IN LATER FORECASTS.
TEMPERATURES ARE FORECAST TO BE NEAR NORMAL WITH HIGHS IN THE LOWER
TO MID 30S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1231 PM EST TUE DEC 16 2014
THE ENTIRE AREA REMAINED UNDER IFR OR LIFR CONDITIONS AS OF 17Z.
EXPECT ONLY A SLOW IMPROVE IN THIS. COLDER AIR AND STRONGER WINDS
WILL ARRIVE EARLY THIS EVENING...AND ALONG WITH THESE FACTORS...
THE IFR SHOULD ALSO IMPROVE INTO THE EVENING. EXPECT THAT MOST OF
THE IFR WILL LIFT TO MVFR AROUND 06Z.
AS THE COLDER AIR CONTINUES TO POUR IN...LAKE EFFECT SNOW SHOWERS
SHOULD DEVELOP LATE TONIGHT/EARLY WEDNESDAY MORNING. THE MEAN LOW
LEVEL FLOW WILL BE 290-300 WHICH FAVORS AZO SEEING THE BEST CHANCE
OF SNOW SHOWERS WITH SOME IFR REDEVELOPING. MKG...GRR...AND BTL
MAY ALSO SEE SOME SNOW SHOWERS INTO WED MORNING.
&&
.MARINE...
ISSUED AT 321 AM EST TUE DEC 16 2014
WINDS WILL INCREASE AS THE LOW MOVES BY THIS AFTERNOON. ISSUED A SCA
TO COVER INCREASED WINDS AND WAVES FROM THIS AFTERNOON THROUGH
THURSDAY MORNING.
&&
.HYDROLOGY...
ISSUED AT 321 AM EST TUE DEC 16 2014
NO HYDRO ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL NOON EST THURSDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...MEADE
AVIATION...JK
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1222 PM EST TUE DEC 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 536 AM EST TUE DEC 16 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A SRN STREAM SHRTWV/LOW OVER
NRN IL AND A NRN STREAM SHRTWV ACROSS NW ONTARIO INTO NW MN. AT THE
SFC...LOW PRES WAS LOCATED OVER NRN IL WITH A TROUGH TO THE NORTH
INTO ERN UPPER MI. 295K-300K ISENTROPIC LIFT AHEAD OF THE NRN IL LOW
HAS BROUGHT AN INCREASE IN PCPN COVERAGE/INTENSITY ACROSS CNTRL
UPPER MI WHILE 850-700 FGEN HAS SUPPORTED THE SNOW INTO WRN UPPER
MI. NRLY LOW LEVEL FLOW WITH THE TIGHTENING PRES GRADIENT BEHIND THE
TROUGH HAS BROUGHT COLDER AIR INTO WRN UPPER MI CHANGING THE RAIN TO
SNOW AT CMX/IWD/LNL. EVEN THROUGH TEMPS HAVE ALSO FALLEN BELOW 32F
AT KMQT...THE CIRCULATION AROUND THE SRN STREAM LOW HAS MAINTAINED
AN ELEVATED WARM LAYER (AROUND 850 MB FROM 1C TO 3C) OVER CENTRAL
UPPER MI. EVEN WITH AIR TEMPS FALLING BELOW FREEZING...THE RECENT
WARM CONDITIONS HAVE LIMITED GLAZE POTENTIAL AS MOST SURFACES HAVE
NOT COOLED OFF AS FAST.
TODAY...AS THE SRN STREAM SHRTWV LIFTS TO THE NW THE NRN STREAM
SHRTWV WILL BECOME THE DOMINANT FEATURE LATE TODAY INTO TONIGHT.
EXPECT THAT THE LINGERING WARM LAYER WILL SUPPORT A BRIEF PERIOD OF
LIGHT FREEZING RAIN OR SLEET THROUGH AROUND 14Z. THE BEST
CHANCE FOR ANY ICING WOULD BE OVER THE HIGHER TERRAIN WHERE TEMPS
HAVE ALREADY FALLEN OFF BELOW FREEZING. OTHERWISE...THE RAIN SNOW
CHANGE OVER IS EXPECTED TO MOVE INTO THE ERN CWA BY AFTERNOON WITH
ALL SNOW AT ERY AFTER 21Z. THE NRN STREAM SHRTWV WITH INCREASING
700-500 MB QVECTOR CONV WILL SUPPORT LIGHT TO MODERATE SNOW ACROSS
UPPER MI TODAY. 1 TO 4 INCH AMOUNTS ARE EXPECTED TODAY WITH HIGHEST
AMOUNTS OVER THE WEST HALF WHERE NRLY WINDS BRING ADDITIONAL LAKE
ENHANCEMENT AND UPSLOPE FLOW AS 850 MB TEMPS FALL INTO THE -6C TO
-10C RANGE.
TONIGHT...AS THE MID LEVEL LOW PIVOTS THROUGH NRN WI...LARGE SCALE
LIFT WILL PREVAIL ACROSS UPPER MI WITH CONTINUED LIGHT SNOWFALL
AMOUNTS. THE HEAVIER SNOWFAL WILL CONTINUE INTO THE NORTH NEAR LAKE
SUPERIOR WITH ADDITIONAL SNOWFALL TOTALS IN THE 3 TO 5 INCH RANGE.
HEADLINES...A WINTER WEATHER ADVISORY WAS ISSUED FOR THE NORTHERN
COUNTIES FOR THE MIXED PRECIPITATION THIS MORNING AND LONG DURATION
LIGHT TO MODERATE SNOW EVENT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 330 AM EST TUE DEC 16 2014
THE UPPER LOW WILL BE OVER THE GREAT LAKES REGION AT 12Z
WEDNESDAY...WHILE THE 1006MB SURFACE LOW IS LOCATED OVER FAR
SOUTHEAST ONTARIO. A MID LEVEL TROUGH WILL BE STRETCHING WEST
ACROSS UPPER MICHIGAN AND WILL BE THE PRIMARY FOCUS FOR THE LIGHT
TO OCCASIONALLY MODERATE SNOW OVER MUCH OF UPPER MICHIGAN. THE
STRONGEST SNOW SHOWERS WILL BE OCCURRING OVER THE WESTERN AND NORTH
CENTRAL U.P. WHERE NORTH-NORTHWEST WINDS AND 850MB TEMPS AROUND
-14C WILL LEAD TO LAKE AND TERRAIN ENHANCEMENT. THESE FAVORABLE
CONDITIONS WILL REMAIN FOR THE MORNING HOURS...BUT THEN THE MID
LEVEL TROUGH WILL DROP SOUTH THROUGH UPPER MICHIGAN WEDNESDAY
AFTERNOON...LEADING TO WINDS SHIFTING TO THE NORTH-NORTHEAST AND
BRINGING WARMER 850MB AIR OVER THE AREA. THUS...SHOULD SEE THE
INTENSITY OF THE LAKE ENHANCEMENT DIMINISHING THROUGH THE AFTERNOON
AND INTO THE EVENING HOURS. IT WILL LIKELY LINGER THE LONGEST OVER
THE NORTH CENTRAL DUE TO THE FAVORABLE WIND DIRECTION. WITH MUCH OF
THE FORCING BELOW THE DGZ...WOULD EXPECT THE SNOW RATIOS FOR MUCH OF
THE AREA TO BE IN THE 12-15 TO 1 RANGE. THE ONE AREA WHERE VALUES
COULD BE A LITTLE HIGHER WOULD BE OVER THE WEST...WHERE THE LOW
LEVEL TEMPERATURES ARE A LITTLE COLDER AND PUTTING MORE OF THE CLOUD
IN THE DGZ. BUT EVEN THEN...A LOT OF THE LAKE ENHANCED FORCING IS AT
OR BELOW THE DGZ...WHICH WOULD SUPPORT RIMING OF ANY DENDRITES AND
IN TURN RATIOS IN THE 15-17 TO ONE RANGE. ALL IN ALL...ADDITIONAL
SNOWFALL AMOUNTS ON WEDNESDAY WILL BE IN THE 1-3 INCH
RANGE...HIGHEST IN THE TERRAIN/LAKE ENHANCED AREA OF NORTH CENTRAL
UPPER MICHIGAN.
WITH THE DRIER/WARMER AIR QUICKLY DIVE INTO THE REGION WEDNESDAY
NIGHT...WILL BRING AN END TO THE SNOW SHOWERS FROM NORTH TO SOUTH
THROUGH THE NIGHT. THIS TRANSITION IS SEVERAL HOURS FASTER THAN
SHOWN 24HRS AGO IN THE MODELS AND HAVE SHOWN THAT FASTER END IN THE
POPS. THAT WARMER/DRIER AIR IS ASSOCIATED WITH AN UPPER RIDGE AND
SURFACE HIGH SHIFTING OVER THE UPPER GREAT LAKES REGION. THESE
FEATURES WILL REMAIN IN PLACE THROUGH AT LEAST FRIDAY. THERE ARE
SOME HINTS OF MOISTURE AROUND 925MB BEING TRAPPED BELOW THE
SUBSIDENCE INVERSION ON THURSDAY. WILL HOLD ONTO MOSTLY CLOUDY SKIES
IN THE MORNING IN THE NORTH-NORTHEAST WIND FAVORED AREAS AND THEN
TRANSITION TO PARTLY CLOUDY IN THE AFTERNOON AS THE SFC-925MB
DELTA-T VALUES BECOME MORE MARGINAL.
MODELS CONTINUE TO DIFFER WITH THE EVOLUTION OF BOTH
UPSTREAM/DOWNSTREAM FEATURES WHICH LEADS TO A LITTLE LOWER
CONFIDENCE IN THE WEEKEND FORECAST. THE FIRST FEATURE THAT THEY
DIFFER ON IS A SHORTWAVE PULLING OUT OF THE SOUTHERN PLAINS AND OFF
THE MID ATLANTIC COAST. THE 12Z GEM/ECMWF DEVELOP A STRONGER LOW
WITH A MUCH MORE AMPLIFIED TROUGH...WHILE THE 00Z GFS IS MUCH WEAKER
WITH THE LOW AND FLATTER WITH THE WAVE. LOOKING AT THE ENSEMBLE
MEANS/MEMBERS...THE 12Z ECMWF MEMBERS ARE REMARKABLY CONSISTENT IN
THE EVOLUTION OF THE LOW OFF THE MID ATLANTIC STATES. BUT WHERE
THINGS DIFFER IS WITH THE HANDLING OF THE NEXT WEAK SHORTWAVE MOVING
THROUGH THE NORTHERN STREAM FLOW SATURDAY INTO SUNDAY. WHILE THE 12Z
GEM/ECMWF OPERATIONAL RUNS HOLD ONTO AN UPPER RIDGE OVER THE UPPER
MISSISSIPPI VALLEY DURING THIS TIME...THE ENSEMBLE MEANS MORE
CLOSELY RESEMBLE THE GFS IN THE IDEA OF A WEAK UPPER TROUGH MOVING
THROUGH THE UPPER MISSISSIPPI VALLEY AND THEN THE UPPER GREAT LAKES
THIS WEEKEND. BASED OFF THE 12Z ENSEMBLE MEANS AND THE 00Z
GEM/ECMWF OPERATIONAL RUNS COMING IN MORE IN LINE WITH THAT
IDEA...WILL FOLLOW THAT FOR THIS FORECAST. BUT EVEN WITH THAT WEAK
UPPER TROUGH MOVING THROUGH...THE SURFACE HIGH WILL BE PERSISTENT
AND SHOULD LEAD TO DRY CONDITIONS. 850MB TEMPS LOOK TO BE AROUND
-6C...WHICH IS EVEN MARGINAL FOR LAKE EFFECT CLOUDS IF THERE WAS
ENOUGH MOISTURE PRESENT...SO WILL GO WITH A DRY FORECAST AND PARTLY
CLOUDY SKIES ON SATURDAY AND MOSTLY CLOUDY ON SUNDAY. HIGHS THURSDAY
WILL START OUT NEAR NORMAL THEN SLOWLY WARM TO SLIGHTLY ABOVE NORMAL
VALUES (UPPER 20S AND LOWER 30S) FOR THE WEEKEND.
HEADING INTO NEXT WEEK...ECMWF/GEM/GFS ENSEMBLE MEANS HAVE BEEN
CONSISTENT FOR THE LAST SEVERAL DAYS TO A WEEK ON AN UPPER TROUGH
DROPPING SOUTHEAST FROM THE GULF OF ALASKA AND INTO THE NORTHERN
CONUS. THIS WILL LEAD TO A COOLER PERIOD AROUND CHRISTMAS AND
LIKELY REMAINING FOR THE END OF DECEMBER. ALTHOUGH IT IS STILL 8-9
DAYS OUT...THE CONSISTENCY IN THE ENSEMBLE MODELS ON THIS IDEA
IS WORTH MENTIONING. THEY CONTINUE TO SHOW A CANADIAN LOW TO DROP
THROUGH ONTARIO OR THE UPPER GREAT LAKES REGION ON THE 24TH OR
25TH. WHILE SNOW AMOUNTS ARE UNFORECASTABLE AT THIS TIME...AT
LEAST LIGHT SNOW IS EXPECTED DURING THAT BUSY HOLIDAY TRAVEL PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1221 PM EST TUE DEC 16 2014
SNOW WILL CONTINUE AT ALL TAF SITES THROUGH THE FCST PERIOD WITH
IFR/LIFR CONDITIONS EXPECTED.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 552 AM EST TUE DEC 16 2014
A TIGHTENING PRES GRADIENT BETWEEN LOW PRES OVER NRN IL LIFTING TO
THE NE AND HIGH PRES OVER MANITOBA INTO THE NRN PLAINS WILL RESULT
IN NORTH WINDS OF 20 TO 30 KNOTS WITH A FEW GALE FORCE GUSTS TO 35
KNOTS TODAY INTO THIS EVENING. AS HIGH PRES BUILDS INTO THE NRN
LAKES FROM WED INTO THU...WINDS WILL DIMINISH TO 20 KNOTS OR LESS.
HIGH PRESSURE WILL THEN DOMINATE INTO THE WEEKEND WITH WINDS
REMAINING BELOW 20 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ WEDNESDAY FOR
MIZ001>006-009-084-085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
841 AM EST TUE DEC 16 2014
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 321 AM EST TUE DEC 16 2014
LOW PRESSURE WILL MOVE ACROSS LOWER MICHIGAN TODAY SPREADING RAIN
SHOWERS AS IT GOES. COLDER AIR WILL WRAP INTO THE SYSTEM LATER THIS
EVENING AND THE RAIN WILL MIX WITH AND THEN CHANGE TO LIGHT SNOW.
THIS WILL BEGIN A PERIOD OF NEAR NORMAL TEMPERATURES...ALTHOUGH MUCH
COLDER THAN WHAT WE`VE SEEN LATELY...THAT WILL LAST THROUGH THE
WEEKEND. LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE WEDNESDAY INTO
THURSDAY WITH LIGHT ACCUMULATIONS POSSIBLE MAINLY WEST OF US-131.
&&
.UPDATE...
ISSUED AT 839 AM EST TUE DEC 16 2014
FOG HAS BECOME DENSE OVER A GOOD PART OF SOUTHWEST LOWER MICHIGAN.
LOOKING AT THE LATEST RAP MODEL DATA...THE LOWEST VISIBILITIES ARE
WHERE THE WINDS ARE CALM...WHICH IS UNDER THE SURFACE LOW. THIS
AREA OF CALM WINDS SHIFTS TO THE EAST NORTHEAST OVER TIME AND BY
16Z IS OVER OUR NORTHEAST CWA....REED CITY TO CLAIR TO NEAR ALMA.
AFTER THAT IT IS GONE. SO I BELIEVE THE FOG AREA WILL PERSIST A
GOOD PART OF THE MORNING BUT ANY ONE LOCATION SHOULD HAVE ONLY 2
TO 3 HOURS OF LOW VISIBILITIES. GIVEN THE SHORT TIME WINDOW FOR
THIS FOG I AS THINKING NOT TO ISSUE A FOG ADVISORY AT THIS POINT.
WE HAVE ALREADY ISSUED A SPECIAL WEATHER STATEMENT ON THE FOG AND
WE WILL CALL THAT GOOD FOR NOW.
OTHERWISE THE ON GOING FORECAST IS GOOD...SHOWERS WILL CONTINUE
THROUGH THE DAY AND CHANGE TO SNOW SHOWERS OVERNIGHT.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 321 AM EST TUE DEC 16 2014
FORECAST CONCERNS DEAL WITH THE EVOLUTION OF THE LOW CURRENTLY
MOVING THROUGH NORTHWEST ILLINOIS.
REGIONAL RADAR AND IR LOOP SHOWS A WELL DEFINED LOW JUST CROSSING
THE MISSISSIPPI. LIGHT RAIN SHOWERS CONTINUE TO PIVOT NORTHWARD FROM
INDIANA AND WE/LL BE LOOKING AT SHOWERS THROUGHOUT THE DAY AS THE
LOW MOVES ACROSS LOWER MICHIGAN. HEAVY RAIN ISN/T ANTICIPATED.
HOWEVER...THERE HAS BEEN SOME LIGHTNING OVER SOUTHERN INDIANA.
MODELS SHOW SOME ELEVATED INSTABILITY DEVELOPING OVER FAR WESTERN
LAKE ERIE THIS MORNING BUT IT PROBABLY TOO FAR AWAY TO RESULT IN
THUNDER IN OUR CWA.
COLDER AIR WILL WRAP INTO THE SYSTEM TONIGHT AND TURN THE LINGERING
PCPN TO LIGHT SNOW SHOWERS. H8 TEMPS FALL TO -12C WEDNESDAY AND THIS
NORMALLY CREATES SUFFICIENT OVER-LAKE INSTABILITY TO GENERATE SNOW
SHOWERS. THE ISSUE THIS TIME THOUGH IS THE SHALLOW MOISTURE. THE
DGZ IS VERY SMALL AND RESIDES AT THE TOP OF THE SHALLOW MOISTURE
AROUND 4K FT. IT/S PROBABLY ENOUGH TO SEE SOME SNOW SHOWERS...AND
LIGHT ACCUMS WEST OF US-131 BUT NOT MUCH MORE THAN THAT. THE SHSN
WILL GRADUALLY DIMINISH WEDNESDAY NIGHT.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 321 AM EST TUE DEC 16 2014
MORE QUIET WEATHER IS IN STORE IN THE LONG TERM PERIOD AS THE SPLIT
FLOW ALOFT CONTINUES AND SURFACE HIGH PRESSURE DOMINATES. THE POLAR
JET STAYS WELL TO OUR NORTH AND THE SRN STREAM BRANCH REMAINS
SOUTH... SO STILL NO MAJOR WINTER SYSTEMS OR ARCTIC AIR IN OUR
FUTURE.
THE MAIN CONCERN WILL BE CLOUD COVER AS STRATUS/FOG/DRIZZLE COULD BE
AN ISSUE AGAIN UNDER THE SFC HIGH. FOR NOW WILL BE OPTIMISTIC WITH
PARTLY SUNNY WORDING BUT THIS COULD CHANGE IN LATER FORECASTS.
TEMPERATURES ARE FORECAST TO BE NEAR NORMAL WITH HIGHS IN THE LOWER
TO MID 30S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 657 AM EST TUE DEC 16 2014
WIDESPREAD LIFR CONDITIONS THIS MORNING WITH CIGS BELOW 500 FT
AND VSBYS BELOW 2 MILES IN LIGHT RAIN/DRIZZLE AND FOG. SLIGHT
IMPROVEMENT INTO IFR CATEGORY EXPECTED THIS AFTERNOON AS THE SFC
LOW WHICH IS OVERHEAD THIS MORNING WORKS EAST AND WINDS
SHIFT/INCREASE OUT OF THE WEST. FURTHER IMPROVEMENT INTO MVFR
CATEGORY IS LIKELY TONIGHT WITH LIGHT RAIN CHANGING TO LIGHT SNOW.
WEST NORTHWEST WINDS WILL BE GUSTY TONIGHT AT 15-25 KTS.
&&
.MARINE...
ISSUED AT 321 AM EST TUE DEC 16 2014
WINDS WILL INCREASE AS THE LOW MOVES BY THIS AFTERNOON. ISSUED A SCA
TO COVER INCREASED WINDS AND WAVES FROM THIS AFTERNOON THROUGH
THURSDAY MORNING.
&&
.HYDROLOGY...
ISSUED AT 321 AM EST TUE DEC 16 2014
NO HYDRO ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY FROM NOON TODAY TO NOON EST THURSDAY FOR
LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
707 AM EST TUE DEC 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 536 AM EST TUE DEC 16 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A SRN STREAM SHRTWV/LOW OVER
NRN IL AND A NRN STREAM SHRTWV ACROSS NW ONTARIO INTO NW MN. AT THE
SFC...LOW PRES WAS LOCATED OVER NRN IL WITH A TROUGH TO THE NORTH
INTO ERN UPPER MI. 295K-300K ISENTROPIC LIFT AHEAD OF THE NRN IL LOW
HAS BROUGHT AN INCREASE IN PCPN COVERAGE/INTENSITY ACROSS CNTRL
UPPER MI WHILE 850-700 FGEN HAS SUPPORTED THE SNOW INTO WRN UPPER
MI. NRLY LOW LEVEL FLOW WITH THE TIGHTENING PRES GRADIENT BEHIND THE
TROUGH HAS BROUGHT COLDER AIR INTO WRN UPPER MI CHANGING THE RAIN TO
SNOW AT CMX/IWD/LNL. EVEN THROUGH TEMPS HAVE ALSO FALLEN BELOW 32F
AT KMQT...THE CIRCULATION AROUND THE SRN STREAM LOW HAS MAINTAINED
AN ELEVATED WARM LAYER (AROUND 850 MB FROM 1C TO 3C) OVER CENTRAL
UPPER MI. EVEN WITH AIR TEMPS FALLING BELOW FREEZING...THE RECENT
WARM CONDITIONS HAVE LIMITED GLAZE POTENTIAL AS MOST SURFACES HAVE
NOT COOLED OFF AS FAST.
TODAY...AS THE SRN STREAM SHRTWV LIFTS TO THE NW THE NRN STREAM
SHRTWV WILL BECOME THE DOMINANT FEATURE LATE TODAY INTO TONIGHT.
EXPECT THAT THE LINGERING WARM LAYER WILL SUPPORT A BRIEF PERIOD OF
LIGHT FREEZING RAIN OR SLEET THROUGH AROUND 14Z. THE BEST
CHANCE FOR ANY ICING WOULD BE OVER THE HIGHER TERRAIN WHERE TEMPS
HAVE ALREADY FALLEN OFF BELOW FREEZING. OTHERWISE...THE RAIN SNOW
CHANGE OVER IS EXPECTED TO MOVE INTO THE ERN CWA BY AFTERNOON WITH
ALL SNOW AT ERY AFTER 21Z. THE NRN STREAM SHRTWV WITH INCREASING
700-500 MB QVECTOR CONV WILL SUPPORT LIGHT TO MODERATE SNOW ACROSS
UPPER MI TODAY. 1 TO 4 INCH AMOUNTS ARE EXPECTED TODAY WITH HIGHEST
AMOUNTS OVER THE WEST HALF WHERE NRLY WINDS BRING ADDITIONAL LAKE
ENHANCEMENT AND UPSLOPE FLOW AS 850 MB TEMPS FALL INTO THE -6C TO
-10C RANGE.
TONIGHT...AS THE MID LEVEL LOW PIVOTS THROUGH NRN WI...LARGE SCALE
LIFT WILL PREVAIL ACROSS UPPER MI WITH CONTINUED LIGHT SNOWFALL
AMOUNTS. THE HEAVIER SNOWFAL WILL CONTINUE INTO THE NORTH NEAR LAKE
SUPERIOR WITH ADDITIONAL SNOWFALL TOTALS IN THE 3 TO 5 INCH RANGE.
HEADLINES...A WINTER WEATHER ADVISORY WAS ISSUED FOR THE NORTHERN
COUNTIES FOR THE MIXED PRECIPITATION THIS MORNING AND LONG DURATION
LIGHT TO MODERATE SNOW EVENT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 330 AM EST TUE DEC 16 2014
THE UPPER LOW WILL BE OVER THE GREAT LAKES REGION AT 12Z
WEDNESDAY...WHILE THE 1006MB SURFACE LOW IS LOCATED OVER FAR
SOUTHEAST ONTARIO. A MID LEVEL TROUGH WILL BE STRETCHING WEST
ACROSS UPPER MICHIGAN AND WILL BE THE PRIMARY FOCUS FOR THE LIGHT
TO OCCASIONALLY MODERATE SNOW OVER MUCH OF UPPER MICHIGAN. THE
STRONGEST SNOW SHOWERS WILL BE OCCURRING OVER THE WESTERN AND NORTH
CENTRAL U.P. WHERE NORTH-NORTHWEST WINDS AND 850MB TEMPS AROUND
-14C WILL LEAD TO LAKE AND TERRAIN ENHANCEMENT. THESE FAVORABLE
CONDITIONS WILL REMAIN FOR THE MORNING HOURS...BUT THEN THE MID
LEVEL TROUGH WILL DROP SOUTH THROUGH UPPER MICHIGAN WEDNESDAY
AFTERNOON...LEADING TO WINDS SHIFTING TO THE NORTH-NORTHEAST AND
BRINGING WARMER 850MB AIR OVER THE AREA. THUS...SHOULD SEE THE
INTENSITY OF THE LAKE ENHANCEMENT DIMINISHING THROUGH THE AFTERNOON
AND INTO THE EVENING HOURS. IT WILL LIKELY LINGER THE LONGEST OVER
THE NORTH CENTRAL DUE TO THE FAVORABLE WIND DIRECTION. WITH MUCH OF
THE FORCING BELOW THE DGZ...WOULD EXPECT THE SNOW RATIOS FOR MUCH OF
THE AREA TO BE IN THE 12-15 TO 1 RANGE. THE ONE AREA WHERE VALUES
COULD BE A LITTLE HIGHER WOULD BE OVER THE WEST...WHERE THE LOW
LEVEL TEMPERATURES ARE A LITTLE COLDER AND PUTTING MORE OF THE CLOUD
IN THE DGZ. BUT EVEN THEN...A LOT OF THE LAKE ENHANCED FORCING IS AT
OR BELOW THE DGZ...WHICH WOULD SUPPORT RIMING OF ANY DENDRITES AND
IN TURN RATIOS IN THE 15-17 TO ONE RANGE. ALL IN ALL...ADDITIONAL
SNOWFALL AMOUNTS ON WEDNESDAY WILL BE IN THE 1-3 INCH
RANGE...HIGHEST IN THE TERRAIN/LAKE ENHANCED AREA OF NORTH CENTRAL
UPPER MICHIGAN.
WITH THE DRIER/WARMER AIR QUICKLY DIVE INTO THE REGION WEDNESDAY
NIGHT...WILL BRING AN END TO THE SNOW SHOWERS FROM NORTH TO SOUTH
THROUGH THE NIGHT. THIS TRANSITION IS SEVERAL HOURS FASTER THAN
SHOWN 24HRS AGO IN THE MODELS AND HAVE SHOWN THAT FASTER END IN THE
POPS. THAT WARMER/DRIER AIR IS ASSOCIATED WITH AN UPPER RIDGE AND
SURFACE HIGH SHIFTING OVER THE UPPER GREAT LAKES REGION. THESE
FEATURES WILL REMAIN IN PLACE THROUGH AT LEAST FRIDAY. THERE ARE
SOME HINTS OF MOISTURE AROUND 925MB BEING TRAPPED BELOW THE
SUBSIDENCE INVERSION ON THURSDAY. WILL HOLD ONTO MOSTLY CLOUDY SKIES
IN THE MORNING IN THE NORTH-NORTHEAST WIND FAVORED AREAS AND THEN
TRANSITION TO PARTLY CLOUDY IN THE AFTERNOON AS THE SFC-925MB
DELTA-T VALUES BECOME MORE MARGINAL.
MODELS CONTINUE TO DIFFER WITH THE EVOLUTION OF BOTH
UPSTREAM/DOWNSTREAM FEATURES WHICH LEADS TO A LITTLE LOWER
CONFIDENCE IN THE WEEKEND FORECAST. THE FIRST FEATURE THAT THEY
DIFFER ON IS A SHORTWAVE PULLING OUT OF THE SOUTHERN PLAINS AND OFF
THE MID ATLANTIC COAST. THE 12Z GEM/ECMWF DEVELOP A STRONGER LOW
WITH A MUCH MORE AMPLIFIED TROUGH...WHILE THE 00Z GFS IS MUCH WEAKER
WITH THE LOW AND FLATTER WITH THE WAVE. LOOKING AT THE ENSEMBLE
MEANS/MEMBERS...THE 12Z ECMWF MEMBERS ARE REMARKABLY CONSISTENT IN
THE EVOLUTION OF THE LOW OFF THE MID ATLANTIC STATES. BUT WHERE
THINGS DIFFER IS WITH THE HANDLING OF THE NEXT WEAK SHORTWAVE MOVING
THROUGH THE NORTHERN STREAM FLOW SATURDAY INTO SUNDAY. WHILE THE 12Z
GEM/ECMWF OPERATIONAL RUNS HOLD ONTO AN UPPER RIDGE OVER THE UPPER
MISSISSIPPI VALLEY DURING THIS TIME...THE ENSEMBLE MEANS MORE
CLOSELY RESEMBLE THE GFS IN THE IDEA OF A WEAK UPPER TROUGH MOVING
THROUGH THE UPPER MISSISSIPPI VALLEY AND THEN THE UPPER GREAT LAKES
THIS WEEKEND. BASED OFF THE 12Z ENSEMBLE MEANS AND THE 00Z
GEM/ECMWF OPERATIONAL RUNS COMING IN MORE IN LINE WITH THAT
IDEA...WILL FOLLOW THAT FOR THIS FORECAST. BUT EVEN WITH THAT WEAK
UPPER TROUGH MOVING THROUGH...THE SURFACE HIGH WILL BE PERSISTENT
AND SHOULD LEAD TO DRY CONDITIONS. 850MB TEMPS LOOK TO BE AROUND
-6C...WHICH IS EVEN MARGINAL FOR LAKE EFFECT CLOUDS IF THERE WAS
ENOUGH MOISTURE PRESENT...SO WILL GO WITH A DRY FORECAST AND PARTLY
CLOUDY SKIES ON SATURDAY AND MOSTLY CLOUDY ON SUNDAY. HIGHS THURSDAY
WILL START OUT NEAR NORMAL THEN SLOWLY WARM TO SLIGHTLY ABOVE NORMAL
VALUES (UPPER 20S AND LOWER 30S) FOR THE WEEKEND.
HEADING INTO NEXT WEEK...ECMWF/GEM/GFS ENSEMBLE MEANS HAVE BEEN
CONSISTENT FOR THE LAST SEVERAL DAYS TO A WEEK ON AN UPPER TROUGH
DROPPING SOUTHEAST FROM THE GULF OF ALASKA AND INTO THE NORTHERN
CONUS. THIS WILL LEAD TO A COOLER PERIOD AROUND CHRISTMAS AND
LIKELY REMAINING FOR THE END OF DECEMBER. ALTHOUGH IT IS STILL 8-9
DAYS OUT...THE CONSISTENCY IN THE ENSEMBLE MODELS ON THIS IDEA
IS WORTH MENTIONING. THEY CONTINUE TO SHOW A CANADIAN LOW TO DROP
THROUGH ONTARIO OR THE UPPER GREAT LAKES REGION ON THE 24TH OR
25TH. WHILE SNOW AMOUNTS ARE UNFORECASTABLE AT THIS TIME...AT
LEAST LIGHT SNOW IS EXPECTED DURING THAT BUSY HOLIDAY TRAVEL PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 705 AM EST TUE DEC 16 2014
A WARM LAYER ALOFT MAY BRING A PERIOD OF SLEET TO SAW THROUGH AROUND
14Z. OTHERWISE...COLD CYCLONIC NRLY FLOW SUPPORTED BY AN UPPER LEVEL
LOW PRESSURE SYSTEM WILL BRING SNOW TO THE TAF SITES THROUGH THE
FCST PERIOD WITH IFR CONDITIONS EXPECTED. THERE MAY ALSO BE SOME
PERIODS OF LIFR VSBY BUT CONFIDENCE IN TIMING ANY EXTENDED PERIOD OF
VSBY BLO 1SM IS LOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 552 AM EST TUE DEC 16 2014
A TIGHTENING PRES GRADIENT BETWEEN LOW PRES OVER NRN IL LIFTING TO
THE NE AND HIGH PRES OVER MANITOBA INTO THE NRN PLAINS WILL RESULT
IN NORTH WINDS OF 20 TO 30 KNOTS WITH A FEW GALE FORCE GUSTS TO 35
KNOTS TODAY INTO THIS EVENING. AS HIGH PRES BUILDS INTO THE NRN
LAKES FROM WED INTO THU...WINDS WILL DIMINISH TO 20 KNOTS OR LESS.
HIGH PRESSURE WILL THEN DOMINATE INTO THE WEEKEND WITH WINDS
REMAINING BELOW 20 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST WEDNESDAY FOR MIZ006-085.
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ WEDNESDAY FOR
MIZ001>005-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
553 AM EST TUE DEC 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 536 AM EST TUE DEC 16 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A SRN STREAM SHRTWV/LOW OVER
NRN IL AND A NRN STREAM SHRTWV ACROSS NW ONTARIO INTO NW MN. AT THE
SFC...LOW PRES WAS LOCATED OVER NRN IL WITH A TROUGH TO THE NORTH
INTO ERN UPPER MI. 295K-300K ISENTROPIC LIFT AHEAD OF THE NRN IL LOW
HAS BROUGHT AN INCREASE IN PCPN COVERAGE/INTENSITY ACROSS CNTRL
UPPER MI WHILE 850-700 FGEN HAS SUPPORTED THE SNOW INTO WRN UPPER
MI. NRLY LOW LEVEL FLOW WITH THE TIGHTENING PRES GRADIENT BEHIND THE
TROUGH HAS BROUGHT COLDER AIR INTO WRN UPPER MI CHANGING THE RAIN TO
SNOW AT CMX/IWD/LNL. EVEN THROUGH TEMPS HAVE ALSO FALLEN BELOW 32F
AT KMQT...THE CIRCULATION AROUND THE SRN STREAM LOW HAS MAINTAINED
AN ELEVATED WARM LAYER (AROUND 850 MB FROM 1C TO 3C) OVER CENTRAL
UPPER MI. EVEN WITH AIR TEMPS FALLING BELOW FREEZING...THE RECENT
WARM CONDITIONS HAVE LIMITED GLAZE POTENTIAL AS MOST SURFACES HAVE
NOT COOLED OFF AS FAST.
TODAY...AS THE SRN STREAM SHRTWV LIFTS TO THE NW THE NRN STREAM
SHRTWV WILL BECOME THE DOMINANT FEATURE LATE TODAY INTO TONIGHT.
EXPECT THAT THE LINGERING WARM LAYER WILL SUPPORT A BRIEF PERIOD OF
LIGHT FREEZING RAIN OR SLEET THROUGH AROUND 14Z. THE BEST
CHANCE FOR ANY ICING WOULD BE OVER THE HIGHER TERRAIN WHERE TEMPS
HAVE ALREADY FALLEN OFF BELOW FREEZING. OTHERWISE...THE RAIN SNOW
CHANGE OVER IS EXPECTED TO MOVE INTO THE ERN CWA BY AFTERNOON WITH
ALL SNOW AT ERY AFTER 21Z. THE NRN STREAM SHRTWV WITH INCREASING
700-500 MB QVECTOR CONV WILL SUPPORT LIGHT TO MODERATE SNOW ACROSS
UPPER MI TODAY. 1 TO 4 INCH AMOUNTS ARE EXPECTED TODAY WITH HIGHEST
AMOUNTS OVER THE WEST HALF WHERE NRLY WINDS BRING ADDITIONAL LAKE
ENHANCEMENT AND UPSLOPE FLOW AS 850 MB TEMPS FALL INTO THE -6C TO
-10C RANGE.
TONIGHT...AS THE MID LEVEL LOW PIVOTS THROUGH NRN WI...LARGE SCALE
LIFT WILL PREVAIL ACROSS UPPER MI WITH CONTINUED LIGHT SNOWFALL
AMOUNTS. THE HEAVIER SNOWFAL WILL CONTINUE INTO THE NORTH NEAR LAKE
SUPERIOR WITH ADDITIONAL SNOWFALL TOTALS IN THE 3 TO 5 INCH RANGE.
HEADLINES...A WINTER WEATHER ADVISORY WAS ISSUED FOR THE NORTHERN
COUNTIES FOR THE MIXED PRECIPITATION THIS MORNING AND LONG DURATION
LIGHT TO MODERATE SNOW EVENT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 330 AM EST TUE DEC 16 2014
THE UPPER LOW WILL BE OVER THE GREAT LAKES REGION AT 12Z
WEDNESDAY...WHILE THE 1006MB SURFACE LOW IS LOCATED OVER FAR
SOUTHEAST ONTARIO. A MID LEVEL TROUGH WILL BE STRETCHING WEST
ACROSS UPPER MICHIGAN AND WILL BE THE PRIMARY FOCUS FOR THE LIGHT
TO OCCASIONALLY MODERATE SNOW OVER MUCH OF UPPER MICHIGAN. THE
STRONGEST SNOW SHOWERS WILL BE OCCURRING OVER THE WESTERN AND NORTH
CENTRAL U.P. WHERE NORTH-NORTHWEST WINDS AND 850MB TEMPS AROUND
-14C WILL LEAD TO LAKE AND TERRAIN ENHANCEMENT. THESE FAVORABLE
CONDITIONS WILL REMAIN FOR THE MORNING HOURS...BUT THEN THE MID
LEVEL TROUGH WILL DROP SOUTH THROUGH UPPER MICHIGAN WEDNESDAY
AFTERNOON...LEADING TO WINDS SHIFTING TO THE NORTH-NORTHEAST AND
BRINGING WARMER 850MB AIR OVER THE AREA. THUS...SHOULD SEE THE
INTENSITY OF THE LAKE ENHANCEMENT DIMINISHING THROUGH THE AFTERNOON
AND INTO THE EVENING HOURS. IT WILL LIKELY LINGER THE LONGEST OVER
THE NORTH CENTRAL DUE TO THE FAVORABLE WIND DIRECTION. WITH MUCH OF
THE FORCING BELOW THE DGZ...WOULD EXPECT THE SNOW RATIOS FOR MUCH OF
THE AREA TO BE IN THE 12-15 TO 1 RANGE. THE ONE AREA WHERE VALUES
COULD BE A LITTLE HIGHER WOULD BE OVER THE WEST...WHERE THE LOW
LEVEL TEMPERATURES ARE A LITTLE COLDER AND PUTTING MORE OF THE CLOUD
IN THE DGZ. BUT EVEN THEN...A LOT OF THE LAKE ENHANCED FORCING IS AT
OR BELOW THE DGZ...WHICH WOULD SUPPORT RIMING OF ANY DENDRITES AND
IN TURN RATIOS IN THE 15-17 TO ONE RANGE. ALL IN ALL...ADDITIONAL
SNOWFALL AMOUNTS ON WEDNESDAY WILL BE IN THE 1-3 INCH
RANGE...HIGHEST IN THE TERRAIN/LAKE ENHANCED AREA OF NORTH CENTRAL
UPPER MICHIGAN.
WITH THE DRIER/WARMER AIR QUICKLY DIVE INTO THE REGION WEDNESDAY
NIGHT...WILL BRING AN END TO THE SNOW SHOWERS FROM NORTH TO SOUTH
THROUGH THE NIGHT. THIS TRANSITION IS SEVERAL HOURS FASTER THAN
SHOWN 24HRS AGO IN THE MODELS AND HAVE SHOWN THAT FASTER END IN THE
POPS. THAT WARMER/DRIER AIR IS ASSOCIATED WITH AN UPPER RIDGE AND
SURFACE HIGH SHIFTING OVER THE UPPER GREAT LAKES REGION. THESE
FEATURES WILL REMAIN IN PLACE THROUGH AT LEAST FRIDAY. THERE ARE
SOME HINTS OF MOISTURE AROUND 925MB BEING TRAPPED BELOW THE
SUBSIDENCE INVERSION ON THURSDAY. WILL HOLD ONTO MOSTLY CLOUDY SKIES
IN THE MORNING IN THE NORTH-NORTHEAST WIND FAVORED AREAS AND THEN
TRANSITION TO PARTLY CLOUDY IN THE AFTERNOON AS THE SFC-925MB
DELTA-T VALUES BECOME MORE MARGINAL.
MODELS CONTINUE TO DIFFER WITH THE EVOLUTION OF BOTH
UPSTREAM/DOWNSTREAM FEATURES WHICH LEADS TO A LITTLE LOWER
CONFIDENCE IN THE WEEKEND FORECAST. THE FIRST FEATURE THAT THEY
DIFFER ON IS A SHORTWAVE PULLING OUT OF THE SOUTHERN PLAINS AND OFF
THE MID ATLANTIC COAST. THE 12Z GEM/ECMWF DEVELOP A STRONGER LOW
WITH A MUCH MORE AMPLIFIED TROUGH...WHILE THE 00Z GFS IS MUCH WEAKER
WITH THE LOW AND FLATTER WITH THE WAVE. LOOKING AT THE ENSEMBLE
MEANS/MEMBERS...THE 12Z ECMWF MEMBERS ARE REMARKABLY CONSISTENT IN
THE EVOLUTION OF THE LOW OFF THE MID ATLANTIC STATES. BUT WHERE
THINGS DIFFER IS WITH THE HANDLING OF THE NEXT WEAK SHORTWAVE MOVING
THROUGH THE NORTHERN STREAM FLOW SATURDAY INTO SUNDAY. WHILE THE 12Z
GEM/ECMWF OPERATIONAL RUNS HOLD ONTO AN UPPER RIDGE OVER THE UPPER
MISSISSIPPI VALLEY DURING THIS TIME...THE ENSEMBLE MEANS MORE
CLOSELY RESEMBLE THE GFS IN THE IDEA OF A WEAK UPPER TROUGH MOVING
THROUGH THE UPPER MISSISSIPPI VALLEY AND THEN THE UPPER GREAT LAKES
THIS WEEKEND. BASED OFF THE 12Z ENSEMBLE MEANS AND THE 00Z
GEM/ECMWF OPERATIONAL RUNS COMING IN MORE IN LINE WITH THAT
IDEA...WILL FOLLOW THAT FOR THIS FORECAST. BUT EVEN WITH THAT WEAK
UPPER TROUGH MOVING THROUGH...THE SURFACE HIGH WILL BE PERSISTENT
AND SHOULD LEAD TO DRY CONDITIONS. 850MB TEMPS LOOK TO BE AROUND
-6C...WHICH IS EVEN MARGINAL FOR LAKE EFFECT CLOUDS IF THERE WAS
ENOUGH MOISTURE PRESENT...SO WILL GO WITH A DRY FORECAST AND PARTLY
CLOUDY SKIES ON SATURDAY AND MOSTLY CLOUDY ON SUNDAY. HIGHS THURSDAY
WILL START OUT NEAR NORMAL THEN SLOWLY WARM TO SLIGHTLY ABOVE NORMAL
VALUES (UPPER 20S AND LOWER 30S) FOR THE WEEKEND.
HEADING INTO NEXT WEEK...ECMWF/GEM/GFS ENSEMBLE MEANS HAVE BEEN
CONSISTENT FOR THE LAST SEVERAL DAYS TO A WEEK ON AN UPPER TROUGH
DROPPING SOUTHEAST FROM THE GULF OF ALASKA AND INTO THE NORTHERN
CONUS. THIS WILL LEAD TO A COOLER PERIOD AROUND CHRISTMAS AND
LIKELY REMAINING FOR THE END OF DECEMBER. ALTHOUGH IT IS STILL 8-9
DAYS OUT...THE CONSISTENCY IN THE ENSEMBLE MODELS ON THIS IDEA
IS WORTH MENTIONING. THEY CONTINUE TO SHOW A CANADIAN LOW TO DROP
THROUGH ONTARIO OR THE UPPER GREAT LAKES REGION ON THE 24TH OR
25TH. WHILE SNOW AMOUNTS ARE UNFORECASTABLE AT THIS TIME...AT
LEAST LIGHT SNOW IS EXPECTED DURING THAT BUSY HOLIDAY TRAVEL PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1237 AM EST TUE DEC 16 2014
ALTHOUGH IFR CONDITIONS WL PREDOMINATE AT THE SITES EARLY THIS MRNG
AS AREA OF LARGER SCALE PCPN MOVES OVHD AND COLDER AIR MOVES INTO
THE UPR LKS BEHIND SLOW MOVING COLD FNT... WEAK UPSLOPE FLOW AT CMX
MAY ALLOW FOR SOME MVFR CONDITIONS THERE EARLY IN THE PERIOD. LATER
ARRIVAL OF THE FNT AND MORE SHALLOW NATURE OF THE COLD AIR INFLOW WL
LEAD TO THE POTENTIAL FOR SOME VLIFR CONDITIONS AT SAW UNTIL
SUNRISE. THEN CYC...GUSTY N FLOW THRU TODAY WL LEAD TO WIDESPREAD
-SN/PREDOMINANT IFR CONDITIONS. SOME HEAVIER SN MAY IMPACT THE SITES
TNGT AS ANOTHER DISTURBANCE SLIDES SE THRU THE UPR LKS...LEADING TO
A PERSISTENCE OF IFR TO LIFR CONDITIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 552 AM EST TUE DEC 16 2014
A TIGHTENING PRES GRADIENT BETWEEN LOW PRES OVER NRN IL LIFTING TO
THE NE AND HIGH PRES OVER MANITOBA INTO THE NRN PLAINS WILL RESULT
IN NORTH WINDS OF 20 TO 30 KNOTS WITH A FEW GALE FORCE GUSTS TO 35
KNOTS TODAY INTO THIS EVENING. AS HIGH PRES BUILDS INTO THE NRN
LAKES FROM WED INTO THU...WINDS WILL DIMINISH TO 20 KNOTS OR LESS.
HIGH PRESSURE WILL THEN DOMINATE INTO THE WEEKEND WITH WINDS
REMAINING BELOW 20 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO 7 PM EST
WEDNESDAY FOR MIZ006-085.
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ WEDNESDAY FOR
MIZ001>005-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR LMZ221-248-
250.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
538 AM EST TUE DEC 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 536 AM EST TUE DEC 16 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A SRN STREAM SHRTWV/LOW OVER
NRN IL AND A NRN STREAM SHRTWV ACROSS NW ONTARIO INTO NW MN. AT THE
SFC...LOW PRES WAS LOCATED OVER NRN IL WITH A TROUGH TO THE NORTH
INTO ERN UPPER MI. 295K-300K ISENTROPIC LIFT AHEAD OF THE NRN IL LOW
HAS BROUGHT AN INCREASE IN PCPN COVERAGE/INTENSITY ACROSS CNTRL
UPPER MI WHILE 850-700 FGEN HAS SUPPORTED THE SNOW INTO WRN UPPER
MI. NRLY LOW LEVEL FLOW WITH THE TIGHTENING PRES GRADIENT BEHIND THE
TROUGH HAS BROUGHT COLDER AIR INTO WRN UPPER MI CHANGING THE RAIN TO
SNOW AT CMX/IWD/LNL. EVEN THROUGH TEMPS HAVE ALSO FALLEN BELOW 32F
AT KMQT...THE CIRCULATION AROUND THE SRN STREAM LOW HAS MAINTAINED
AN ELEVATED WARM LAYER (AROUND 850 MB FROM 1C TO 3C) OVER CENTRAL
UPPER MI. EVEN WITH AIR TEMPS FALLING BELOW FREEZING...THE RECENT
WARM CONDITIONS HAVE LIMITED GLAZE POTENTIAL AS MOST SURFACES HAVE
NOT COOLED OFF AS FAST.
TODAY...AS THE SRN STREAM SHRTWV LIFTS TO THE NW THE NRN STREAM
SHRTWV WILL BECOME THE DOMINANT FEATURE LATE TODAY INTO TONIGHT.
EXPECT THAT THE LINGERING WARM LAYER WILL SUPPORT A BRIEF PERIOD OF
LIGHT FREEZING RAIN OR SLEET THROUGH AROUND 14Z. THE BEST
CHANCE FOR ANY ICING WOULD BE OVER THE HIGHER TERRAIN WHERE TEMPS
HAVE ALREADY FALLEN OFF BELOW FREEZING. OTHERWISE...THE RAIN SNOW
CHANGE OVER IS EXPECTED TO MOVE INTO THE ERN CWA BY AFTERNOON WITH
ALL SNOW AT ERY AFTER 21Z. THE NRN STREAM SHRTWV WITH INCREASING
700-500 MB QVECTOR CONV WILL SUPPORT LIGHT TO MODERATE SNOW ACROSS
UPPER MI TODAY. 1 TO 4 INCH AMOUNTS ARE EXPECTED TODAY WITH HIGHEST
AMOUNTS OVER THE WEST HALF WHERE NRLY WINDS BRING ADDITIONAL LAKE
ENHANCEMENT AND UPSLOPE FLOW AS 850 MB TEMPS FALL INTO THE -6C TO
-10C RANGE.
TONIGHT...AS THE MID LEVEL LOW PIVOTS THROUGH NRN WI...LARGE SCALE
LIFT WILL PREVAIL ACROSS UPPER MI WITH CONTINUED LIGHT SNOWFALL
AMOUNTS. THE HEAVIER SNOWFAL WILL CONTINUE INTO THE NORTH NEAR LAKE
SUPERIOR WITH ADDITIONAL SNOWFALL TOTALS IN THE 3 TO 5 INCH RANGE.
HEADLINES...A WINTER WEATHER ADVISORY WAS ISSUED FOR THE NORTHERN
COUNTIES FOR THE MIXED PRECIPITATION THIS MORNING AND LONG DURATION
LIGHT TO MODERATE SNOW EVENT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 330 AM EST TUE DEC 16 2014
THE UPPER LOW WILL BE OVER THE GREAT LAKES REGION AT 12Z
WEDNESDAY...WHILE THE 1006MB SURFACE LOW IS LOCATED OVER FAR
SOUTHEAST ONTARIO. A MID LEVEL TROUGH WILL BE STRETCHING WEST
ACROSS UPPER MICHIGAN AND WILL BE THE PRIMARY FOCUS FOR THE LIGHT
TO OCCASIONALLY MODERATE SNOW OVER MUCH OF UPPER MICHIGAN. THE
STRONGEST SNOW SHOWERS WILL BE OCCURRING OVER THE WESTERN AND NORTH
CENTRAL U.P. WHERE NORTH-NORTHWEST WINDS AND 850MB TEMPS AROUND
-14C WILL LEAD TO LAKE AND TERRAIN ENHANCEMENT. THESE FAVORABLE
CONDITIONS WILL REMAIN FOR THE MORNING HOURS...BUT THEN THE MID
LEVEL TROUGH WILL DROP SOUTH THROUGH UPPER MICHIGAN WEDNESDAY
AFTERNOON...LEADING TO WINDS SHIFTING TO THE NORTH-NORTHEAST AND
BRINGING WARMER 850MB AIR OVER THE AREA. THUS...SHOULD SEE THE
INTENSITY OF THE LAKE ENHANCEMENT DIMINISHING THROUGH THE AFTERNOON
AND INTO THE EVENING HOURS. IT WILL LIKELY LINGER THE LONGEST OVER
THE NORTH CENTRAL DUE TO THE FAVORABLE WIND DIRECTION. WITH MUCH OF
THE FORCING BELOW THE DGZ...WOULD EXPECT THE SNOW RATIOS FOR MUCH OF
THE AREA TO BE IN THE 12-15 TO 1 RANGE. THE ONE AREA WHERE VALUES
COULD BE A LITTLE HIGHER WOULD BE OVER THE WEST...WHERE THE LOW
LEVEL TEMPERATURES ARE A LITTLE COLDER AND PUTTING MORE OF THE CLOUD
IN THE DGZ. BUT EVEN THEN...A LOT OF THE LAKE ENHANCED FORCING IS AT
OR BELOW THE DGZ...WHICH WOULD SUPPORT RIMING OF ANY DENDRITES AND
IN TURN RATIOS IN THE 15-17 TO ONE RANGE. ALL IN ALL...ADDITIONAL
SNOWFALL AMOUNTS ON WEDNESDAY WILL BE IN THE 1-3 INCH
RANGE...HIGHEST IN THE TERRAIN/LAKE ENHANCED AREA OF NORTH CENTRAL
UPPER MICHIGAN.
WITH THE DRIER/WARMER AIR QUICKLY DIVE INTO THE REGION WEDNESDAY
NIGHT...WILL BRING AN END TO THE SNOW SHOWERS FROM NORTH TO SOUTH
THROUGH THE NIGHT. THIS TRANSITION IS SEVERAL HOURS FASTER THAN
SHOWN 24HRS AGO IN THE MODELS AND HAVE SHOWN THAT FASTER END IN THE
POPS. THAT WARMER/DRIER AIR IS ASSOCIATED WITH AN UPPER RIDGE AND
SURFACE HIGH SHIFTING OVER THE UPPER GREAT LAKES REGION. THESE
FEATURES WILL REMAIN IN PLACE THROUGH AT LEAST FRIDAY. THERE ARE
SOME HINTS OF MOISTURE AROUND 925MB BEING TRAPPED BELOW THE
SUBSIDENCE INVERSION ON THURSDAY. WILL HOLD ONTO MOSTLY CLOUDY SKIES
IN THE MORNING IN THE NORTH-NORTHEAST WIND FAVORED AREAS AND THEN
TRANSITION TO PARTLY CLOUDY IN THE AFTERNOON AS THE SFC-925MB
DELTA-T VALUES BECOME MORE MARGINAL.
MODELS CONTINUE TO DIFFER WITH THE EVOLUTION OF BOTH
UPSTREAM/DOWNSTREAM FEATURES WHICH LEADS TO A LITTLE LOWER
CONFIDENCE IN THE WEEKEND FORECAST. THE FIRST FEATURE THAT THEY
DIFFER ON IS A SHORTWAVE PULLING OUT OF THE SOUTHERN PLAINS AND OFF
THE MID ATLANTIC COAST. THE 12Z GEM/ECMWF DEVELOP A STRONGER LOW
WITH A MUCH MORE AMPLIFIED TROUGH...WHILE THE 00Z GFS IS MUCH WEAKER
WITH THE LOW AND FLATTER WITH THE WAVE. LOOKING AT THE ENSEMBLE
MEANS/MEMBERS...THE 12Z ECMWF MEMBERS ARE REMARKABLY CONSISTENT IN
THE EVOLUTION OF THE LOW OFF THE MID ATLANTIC STATES. BUT WHERE
THINGS DIFFER IS WITH THE HANDLING OF THE NEXT WEAK SHORTWAVE MOVING
THROUGH THE NORTHERN STREAM FLOW SATURDAY INTO SUNDAY. WHILE THE 12Z
GEM/ECMWF OPERATIONAL RUNS HOLD ONTO AN UPPER RIDGE OVER THE UPPER
MISSISSIPPI VALLEY DURING THIS TIME...THE ENSEMBLE MEANS MORE
CLOSELY RESEMBLE THE GFS IN THE IDEA OF A WEAK UPPER TROUGH MOVING
THROUGH THE UPPER MISSISSIPPI VALLEY AND THEN THE UPPER GREAT LAKES
THIS WEEKEND. BASED OFF THE 12Z ENSEMBLE MEANS AND THE 00Z
GEM/ECMWF OPERATIONAL RUNS COMING IN MORE IN LINE WITH THAT
IDEA...WILL FOLLOW THAT FOR THIS FORECAST. BUT EVEN WITH THAT WEAK
UPPER TROUGH MOVING THROUGH...THE SURFACE HIGH WILL BE PERSISTENT
AND SHOULD LEAD TO DRY CONDITIONS. 850MB TEMPS LOOK TO BE AROUND
-6C...WHICH IS EVEN MARGINAL FOR LAKE EFFECT CLOUDS IF THERE WAS
ENOUGH MOISTURE PRESENT...SO WILL GO WITH A DRY FORECAST AND PARTLY
CLOUDY SKIES ON SATURDAY AND MOSTLY CLOUDY ON SUNDAY. HIGHS THURSDAY
WILL START OUT NEAR NORMAL THEN SLOWLY WARM TO SLIGHTLY ABOVE NORMAL
VALUES (UPPER 20S AND LOWER 30S) FOR THE WEEKEND.
HEADING INTO NEXT WEEK...ECMWF/GEM/GFS ENSEMBLE MEANS HAVE BEEN
CONSISTENT FOR THE LAST SEVERAL DAYS TO A WEEK ON AN UPPER TROUGH
DROPPING SOUTHEAST FROM THE GULF OF ALASKA AND INTO THE NORTHERN
CONUS. THIS WILL LEAD TO A COOLER PERIOD AROUND CHRISTMAS AND
LIKELY REMAINING FOR THE END OF DECEMBER. ALTHOUGH IT IS STILL 8-9
DAYS OUT...THE CONSISTENCY IN THE ENSEMBLE MODELS ON THIS IDEA
IS WORTH MENTIONING. THEY CONTINUE TO SHOW A CANADIAN LOW TO DROP
THROUGH ONTARIO OR THE UPPER GREAT LAKES REGION ON THE 24TH OR
25TH. WHILE SNOW AMOUNTS ARE UNFORECASTABLE AT THIS TIME...AT
LEAST LIGHT SNOW IS EXPECTED DURING THAT BUSY HOLIDAY TRAVEL PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1237 AM EST TUE DEC 16 2014
ALTHOUGH IFR CONDITIONS WL PREDOMINATE AT THE SITES EARLY THIS MRNG
AS AREA OF LARGER SCALE PCPN MOVES OVHD AND COLDER AIR MOVES INTO
THE UPR LKS BEHIND SLOW MOVING COLD FNT... WEAK UPSLOPE FLOW AT CMX
MAY ALLOW FOR SOME MVFR CONDITIONS THERE EARLY IN THE PERIOD. LATER
ARRIVAL OF THE FNT AND MORE SHALLOW NATURE OF THE COLD AIR INFLOW WL
LEAD TO THE POTENTIAL FOR SOME VLIFR CONDITIONS AT SAW UNTIL
SUNRISE. THEN CYC...GUSTY N FLOW THRU TODAY WL LEAD TO WIDESPREAD
-SN/PREDOMINANT IFR CONDITIONS. SOME HEAVIER SN MAY IMPACT THE SITES
TNGT AS ANOTHER DISTURBANCE SLIDES SE THRU THE UPR LKS...LEADING TO
A PERSISTENCE OF IFR TO LIFR CONDITIONS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 311 PM EST MON DEC 15 2014
COLDER AIR WILL MOVE INTO THE AREA THIS EVENING REDUCING THE FOG.
EXPECT N-NW WINDS OF 20-30KTS LATE THIS EVENING INTO EARLY TUESDAY
EVENING. A FEW GALE FORCE GUSTS TO 35KTS WILL BE POSSIBLE AND THIS
WILL BE THE STRONGEST WIND FORECAST FOR THE ENTIRE FORECAST. NO
GALES SEEN ANYTIME SOON OTHERWISE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO 7 PM EST
WEDNESDAY FOR MIZ006-085.
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ WEDNESDAY FOR
MIZ001>005-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR LMZ221-248-
250.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...KC
MARINE...07
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
835 PM MST WED DEC 17 2014
.UPDATE...
RADAR ECHOES BOTH FROM ROUNDUP TO COLSTRIP AND AROUND BAKER ARE ON
A DOWNWARD TREND AS OF MID EVENING...AND IT SEEMS NOT MUCH REACHED
THE GROUND UNDER THEM TO BEGIN WITH. WE THUS DROPPED POPS FOR THIS
EVENING AND INSTEAD WENT WITH A SCATTERED FLURRY MENTION IN SOUTH-
EASTERN MT. WE ALSO EXTENDED IT THROUGH THE NIGHT...AND RIGHT INTO
THURSDAY MORNING AROUND BAKER AS A WEAK SHORTWAVE TROUGH CONTINUES
TO MOVE FROM EASTERN MT INTO ND. WE KEPT PATCHY FOG IN PLAY ACROSS
FAR SOUTHEASTERN MT TONIGHT AS WELL WITH SOME SUPPORT FOR IT STILL
IN RECENT HRRR RUNS. LOW-LEVEL WINDS ARE ALMOST 10 KT THOUGH AS OF
03 UTC AND IF THAT TREND CONTINUES THEN NEAR-SURFACE FLOW MIGHT BE
TOO TURBULENT FOR VISIBILITY TO LOWER VERY FAR OR FOR VERY LONG.
WE ALSO INCREASED LOWS A BIT TONIGHT GIVEN CLOUDS ACROSS SOUTHEAST
MT AND MODEST SOUTHWEST WINDS TIED TO WEAK LEE-SIDE TROUGHING OVER
SOUTH CENTRAL MT. SCHULTZ
&&
.SHORT TERM...VALID FOR THU AND FRI...
WEAK UPPER LOW PRESSURE SYSTEM WILL MOVE ACROSS NORTHERN MONTANA
TONIGHT AND WILL BRING AREAS OF LIGHT SNOW THIS EVENING ACROSS OUR
NORTHEAST ZONES. SNOW IS EXPECTED TO BE VERY LIGHT WITH NO
ACCUMULATIONS. AS THE LOW MOVES TO OUR EAST TONIGHT...SOME
CLEARING IS EXPECTED ACROSS OUR WESTERN AND CENTRAL ZONES. THIS
WILL ALLOW FOR COOLER OVERNIGHT LOW TEMPERATURES WITH TEENS TO
LOWER 20S. HRRR IS INDICATING FOG TO REDEVELOP OVER SOUTHERN
POWDER RIVER AND CARTER COUNTIES TONIGHT AS LOW LEVEL MOISTURE
REMAINS POOLED OVER THESE AREAS. DID INCLUDED PATCHY FOG FOR
PORTIONS OF SOUTHEAST MONTANA TONIGHT. WEAK SHORT WAVE TO MOVE
THROUGH THURSDAY WHICH WHICH WILL BRING SCATTERED SNOW SHOWERS TO
OUR SOUTHWEST MOUNTAINS. DRY WEATHER AND SLOWLY WARMING
TEMPERATURES WILL CONTINUE INTO FRIDAY AS SHORT WAVE RIDGING MOVES
IN OVER THE REGION. HIGH TEMPERATURES WILL BE IN THE UPPER 30S TO
LOWER 40S BOTH THURSDAY AND FRIDAY. RICHMOND
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT INTO EARLY NEXT WEEK.
WHILE THE FINER DETAILS MAY DIFFER...THE OVERALL UNSETTLED
PATTERN IN THE EXTENDED CONTINUES. AFTER THE RIDGING FRIDAY...A
WEAK SHORTWAVE WILL CROSS THE STATE...BRINGING ANOTHER CHANCE FOR
LIGHT PRECIP TO THE MOUNTAINS. UPPER LEVEL FLOW BEGINS TO INCREASE
SATURDAY NIGHT AS A PACIFIC JET STARTS MOVING INTO THE STATE. LEE
SIDE TROUGHING DEVELOPS...WITH A SURFACE LOW DEVELOPING OVER
SOUTHERN ALBERTA. IN RESPONSE...THE PRESSURE GRADIENT TIGHTENS
OVER SOUTHERN MONTANA...RESULTING IN STRONGER WINDS DEVELOPING
FIRST IN THE GAP AREAS...THEN SPREADING OUT TO AROUND BILLINGS.
MEX MOS FOR LIVINGSTON HAS WINDS INCREASING INTO 30 MPH TO NEAR 40
MPH RANGE SUNDAY AFTERNOON. STILL KEEPING GRIDS SUB ADVISORY GIVEN
THIS IS STILL FOUR DAYS OUT...BUT IF CURRENT TRENDS HOLD...LOOKING
AT ANOTHER WIND EVENT DURING THE DAY SUNDAY.
AS THE LOW TRACKS OUT OF CANADA INTO THE NORTHERN PLAINS
MONDAY...A COLD FRONT MOVES THROUGH THE AREA. WITH AMPLE MOISTURE
STILL BRING TRANSPORTED INTO THE AREA...POPS CONTINUE MONDAY INTO
TUESDAY. TEMPERATURES WILL REMAIN RELATIVELY WARM...SO MUCH OF THE
CENTRAL ZONES STILL LOOK TO GET RAIN. FARTHER EAST WARDS MILES
CITY AND BAKER...WHERE TEMPERATURES ARE A BIT COOLER...MAY SEE
SOME FREEZING RAIN. WINDS WILL ALSO BE MORE NORTH WESTERLY...SO
NOT AS MUCH OF AN UP SLOPE FLOW EVENT. THINGS BEGIN TO TAPPER
OFF...WITH TEMPERATURES COOLING BACK INTO THE 30S FOR HIGHS.
LOOKING AHEAD TO CHRISTMAS EVE AND CHRISTMAS...ANOTHER LOW
DEVELOPS AND TRACKS ACROSS MONTANA...GIVING THE AREA A SHOT AT
MORE PRECIP. WITH THE SYSTEM...THE AIR MASS IN PLACE WILL BE
COLDER...WITH 850MB TEMPERATURES BELOW FREEZING. THE THE GFS AND
ECMWF ARE SUGGESTING A SHOT AT A WHITE CHRISTMAS...WILL CONTINUE
TO WATCH THIS. REIMER
&&
.AVIATION...
FLIGHT CONDITIONS REMAIN MAINLY VFR/MVFR OVERNIGHT AND INTO
TOMORROW....HOWEVER SOME PATCHY FOG IS POSSIBLE FROM KMLS SOUTH
AND EAST. OCCASIONAL MOUNTAIN OBSCURATION WILL CONTINUE
OVERNIGHT...WITH MID LEVEL CLOUDS CROSSING THE REGION. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
THU FRI SAT SUN MON TUE WED
-----------------------------------------------------------
BIL 023/038 023/038 027/041 027/046 033/045 026/038 022/033
00/B 00/B 11/B 13/W 32/W 21/N 23/J
LVM 024/042 024/040 027/043 028/046 035/045 022/039 023/035
01/N 11/N 21/B 24/W 43/W 21/N 33/J
HDN 018/037 015/037 020/040 021/044 029/043 021/037 020/034
10/B 00/B 01/B 13/W 33/W 21/B 22/J
MLS 018/038 019/037 021/040 022/042 029/040 025/036 020/031
10/B 00/B 11/B 13/W 22/W 11/B 11/E
4BQ 017/041 017/040 019/041 022/044 030/042 024/037 019/033
10/B 00/B 11/B 12/W 23/W 21/B 22/J
BHK 016/036 019/037 019/040 021/042 026/037 021/033 017/027
11/M 10/B 01/B 02/W 22/W 11/N 11/B
SHR 012/041 015/038 020/040 019/043 030/042 022/037 019/033
10/B 10/B 11/B 13/W 34/W 32/J 22/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
932 PM MST MON DEC 15 2014
.UPDATE...
AREAS WHERE MOST MOISTURE FELL STILL UNDER THE INFLUENCE OF
STRATUS AND THIS IS DELAYING FOG DEVELOPMENT. HRRR SHOWS FOG
DEVELOPING BUT HANGING OVER THE LOWER ELEVATIONS AND NOT IMPACTING
KBIL UNTIL 09Z. THIS IS SUPPORTED BY MODELS SHOWING WINDS DYING
DOWN AT THAT POINT WHICH SHOULD ALLOW FOG LAYER TO DEEPEN. NO
UPDATES AS CURRENT FORECAST LOOKS GOOD. BORSUM
&&
.SHORT TERM...VALID FOR TUE AND WED...
WEAK UPPER LEVEL RIDGING MOVING ACROSS THE AREA TONIGHT. THIS
WILL KEEP DEFORMATION ZONE NORTH OF OUR AREA AND LITTLE CHANCE OF
PRECIPITATION OVERNIGHT. LOW LEVELS WILL REMAIN SATURATED
OVERNIGHT AND FOG WILL BE POSSIBLE FROM BIG TIMBER EAST OVER
NIGHT. A FEW AREAS MAY SEE DENSE FOG BUT THESE AREAS SHOULD BE
ISOLATED AND WILL NOT ISSUE ANY ADVISORY AT THIS TIME. UPPER RIDGE
WILL SHIFT EASTWARD ON TUESDAY WHICH WILL ALLOW PACIFIC ENERGY TO
MOVE IN FROM THE SOUTHWEST. THIS WILL BRING A FEW MOUNTAINS SNOW
SHOWERS. MODELS ARE ALL CONSISTENT IN DEVELOPING AN UPPER LOW
CIRCULATION OVER MONTANA TUESDAY NIGHT AND WEDNESDAY. BOTH
GFS/ECMWF BRING WEAK QG FORCING ACROSS THE AREA AND HAVE INCREASED
POPS OVER OUR WESTERN ZONES FOR THIS TIME PERIOD. MOISTURE WILL
ADVECT BACK INTO THE AREA BUT LOW LEVEL FORCING IS VERY MINIMAL
WITH WEAK WIND FIELD ALOFT. SNOWFALL FROM THIS SYSTEM WILL BE
VERY LIGHT. TEMPERATURES REMAINING NEAR OR SLIGHTLY BELOW SEASONAL
NORMALS FOR TONIGHT THROUGH WEDNESDAY NIGHT WITH LITTLE MIXING TO
TAKE PLACE. RICHMOND
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
WEAK FLOW STILL DOMINATES MUCH OF THE EXTENDED...AND WITH THAT
CONTINUED UNCERTAINTY IN THE MODELS. AS A WEAK WAVE MOVES THROUGH
THE AREA THURSDAY...PRECIP CHANCES REMAIN IN THE WESTERN
MOUNTAINS. FRIDAY A WEAK RIDGE MOVES IN AND THE AREA WILL DRY OUT.
AS WE GO THROUGH THE DAY SUNDAY...THE FLOW ALOFT WILL INCREASE AS
A JET MOVES INTO THE PACIFIC NORTH WEST. OVER THE NEXT COUPLE OF
DAYS...THERE IS SOME DIFFERENCE IN THE MODELS IN HOW THEY HANDLE
EVOLUTION OF THE JET...WHICH WILL BE SOMETHING TO WATCH. THE
PRESSURE GRADIENT WILL START TO TIGHTEN UP AS A SURFACE LOW
DEVELOPS IN SOUTHERN CANADA. SUNDAY NIGHT INTO MONDAY WILL BE
WINDY FROM THE FOOTHILLS OUT TO AROUND BILLINGS.
THE MODELS CONTINUE TO SHOW A FRONT PUSHING THROUGH THE AREA
DURING THE DAY MONDAY. THE LATEST GUIDANCE...ESPECIALLY THE
GFS...HAS TRENDED TEMPERATURES WARMER MONDAY AHEAD OF THE
FRONT...DUE TO COMPRESSIONAL WARMING. HAVE CONTINUED THE CHANCE
POPS ACROSS THE AREA MONDAY AS THE FRONT MOVES THROUGH THE AREA.
TEMPERATURES WILL IN GENERAL BE ABOVE NORMAL. REIMER
&&
.AVIATION...
FOG HAS DEVELOPED IN BILLINGS...AND PATCHY FOG IS POSSIBLE ACROSS
MOST OF THE AREA OVERNIGHT...WITH THE EXCEPTION OF LIVINGSTON.
FOG WILL RESULT IN LOCALIZED IFR OR LOWER CONDITIONS. OTHERWISE
VFR CONDITIONS WILL PREVAIL. OCCASIONAL MOUNTAIN OBSCURATIONS ARE
EXPECTED THROUGHOUT THE NIGHT. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
TUE WED THU FRI SAT SUN MON
-----------------------------------------------------------
BIL 014/028 019/036 022/038 023/038 024/042 024/043 032/047
00/B 11/B 11/B 10/U 01/N 11/N 13/W
LVM 015/034 023/042 024/041 023/041 025/043 024/042 033/046
01/B 22/W 11/B 11/U 11/N 12/W 23/W
HDN 008/029 014/034 014/037 017/037 016/040 018/041 026/045
00/B 12/J 11/B 10/U 01/B 11/B 13/W
MLS 012/027 015/030 017/037 020/037 018/038 021/040 028/044
00/B 11/B 11/B 10/U 01/U 11/B 12/W
4BQ 012/030 016/034 017/039 018/040 017/041 020/042 026/046
00/B 12/J 11/B 10/U 00/U 11/B 13/W
BHK 012/024 011/028 015/035 019/038 018/037 020/039 025/043
00/B 01/B 11/B 11/U 00/U 11/B 13/W
SHR 009/030 016/036 015/037 016/038 017/040 018/041 024/044
00/B 11/B 11/B 11/U 01/U 11/B 12/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
532 PM CST WED DEC 17 2014
.SYNOPSIS...
ISSUED AT 325 PM CST WED DEC 17 2014
AN ACTIVE H5 PATTERN CONTINUES ACROSS THE LOWER 48 TDY
WITH NUMEROUS DISTURBANCES AND A CLOSED LOW NOTED OVER THE CONUS.
CLOSED LOW PRESSURE WAS NOTED OVER LAKE HURON AND EXTENDED WWD INTO
NRN WISCONSIN. HIGH PRESSURE WAS NOTED OVER NRN MANITOBA. ACROSS THE
WESTERN HALF OF THE CONUS...SHORTWAVES WERE NOTED OVER SERN
MT....SWRN NEW MEXICO...AND THE CALIFORNIA DESERT. HT FALLS OF 50 TO
70 METERS EXTENDED FROM EASTERN ARIZONA INTO SWRN KS. IN ASSOCIATION
WITH THE CLOSED LOW OVER THE GREAT LAKES...A NICE 50 TO 90 KT JET
STREAK EXTENDED FROM THE MID MISSOURI RIVER...EAST TO VIRGINIA AND
NORTH CAROLINA. HT FALLS IN ASSOCIATION WITH THE CLOSED LOW WERE
MOST PRONOUNCED OVER NEW ENGLAND...WHERE 50 TO 120 METER FALLS WERE
NOTED. AT THE SURFACE...ARCTIC HIGH PRESSURE WAS ANCHORED ACROSS THE
EASTERN DAKOTAS...SSE INTO MISSOURI. WEST OF THIS FEATURE...WEAK
SERLY WINDS WERE NOTED ALONG WITH PESKY LOW LEVEL CLOUDINESS AND
PATCHY FOG. TEMPERATURES THIS AFTERNOON WERE COLD WITH READINGS IN
THE LOWER 20S ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 325 PM CST WED DEC 17 2014
DESPITE THE MAIN UPPER PV ANOMALY AND ASSOCIATED LARGE SCALE FORCING
IS SOUTH OF THE AREA AND MOVING EASTWARD...SEVERAL FORECASTING
ISSUES REMAIN. THE STRATUS LAYER IS WARM ENOUGH TO CONTAIN
SUPERCOOLED LIQUID AND HENCE FALL TO THE GROUND IN WEAK UPSLOPE FLOW
AS FREEZING DRIZZLE IN SOME AREAS OF SOUTHWEST NEBRASKA THIS
AFTERNOON. RAP BUFR SOUNDINGS SUGGEST MINIMAL LIFT THROUGH THE
REMAINING AFTERNOON HOURS...BUT INCREASING SLIGHTLY THIS EVENING AND
OVERNIGHT. IR SAT PICS SHOW MID LEVEL CLOUDS TRYING TO MOVE OVER THE
TOP OF THE EXISTING LOW LEVEL STRATUS BUT HAVING A HARD TIME AS MID
LEVELS ARE QUITE DRY INITIALLY. BELIEVE THE INCREASING UPWARD
VERTICAL MOTION AS A RESULT OF WEAK MID LEVEL FRONTOGENESIS WILL
EVENTUALLY HELP TO MOISTEN THE MID LEVELS...BUT SOUNDINGS STILL SHOW
TOO MUCH DRY AIR TO CONNECT A SATURATED SNOW PRODUCING LAYER WITH
THE MOIST LOW LEVELS BELOW. THE END RESULT...BASED ON FORECAST
SOUNDINGS...WILL BE FREEZING DRIZZLE ESPECIALLY ACROSS THE SOUTHWEST
PORTION OF NEBRASKA THIS EVENING AND DURING THE OVERNIGHT. NEAR TERM
ENSEMBLES SUGGEST THE POSSIBILITY OF A SMALL BAND OF LIGHT SNOW FROM
SOUTHEAST FRONTIER COUNTY NORTHEASTWARD INTO CUSTER...BUT CONFIDENCE
IN SUCH A SMALL SCALE FEATURE BEING ABLE TO FULLY SATURATE THE
ATMOSPHERIC COLUMN TO SUPPORT LIGHT SNOW IS NOT HIGH...SO HAVE LEFT
PRECIPITATION MENTION AS FREEZING DRIZZLE FOR NOW.
FURTHER NORTH AND WEST...SOUTHERLY AND SOUTHEASTERLY WINDS WILL
CONTINUE TO SUSTAIN MOIST LOW LEVELS IN THE EASTERN PANHANDLE...BUT
MID AND UPPER LEVEL DRYING WILL BE GREATER HERE WHICH LEAVES A
BETTER SCENARIO FOR FOG AND HAVE THEREFORE INCLUDED THAT MENTION
THERE INTO THE MORNING HOURS. FOG WILL BE OCCURRING IN SNOW COVERED
AREAS WHICH WILL MEAN SOME DEPOSITION ON ROADS WILL BE POSSIBLE SO
THE MENTION OF FREEZING FOG WAS INCLUDED.
TOMORROW AFTERNOON CLOUDS WILL THIN ALTHOUGH STILL HAVE MUCH OF THE
AREA WITH A SNOW PACK. THIS WILL LIMIT THE ABILITY TO WARM...WITH
TEMPS STRUGGLING TO REACH FREEZING. SOME PARTIAL SUN IS EXPECTED
ACROSS WESTERN NEBRASKA THANKS TO SOME WESTERLY DOWNSLOPING WINDS
WHICH IS WHERE FORECAST HIGHS ARE THE WARMEST.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 325 PM CST WED DEC 17 2014
MID RANGE...THURSDAY NIGHT THROUGH SATURDAY...THE MAIN
FORECAST CHALLENGES IN THE MID RANGE ARE THE THREAT FOR FREEZING
DRIZZLE THURSDAY NIGHT INTO FRIDAY MORNING...AS WELL AS CLOUD COVER
AND TEMPERATURES. FOR THURSDAY NIGHT...WITH THE EXCEPTION OF THE FAR
NORTHWESTERN CWA...LOW CLOUDS AND AN ARCTIC DRAPE WILL REMAIN
ENTRENCHED ACROSS THE BULK OF THE FORECAST AREA. BOTH THE NAM AND
GFS SOLNS THIS MORNING PER FCST SOUNDINGS ARE INDICATING A NICE
LAYER OF NEAR 100 PERCENT RH FROM THE SURFACE TO 1000 TO 1500FT AGL.
WITHIN THIS LAYER...WEAK VEERING OF THE WINDS ARE PRESENT ALONG WITH
SOME WEAK OMEGA AND TEMPERATURES RANGING FROM ZERO TO -5C IN THIS
MOIST LAYER. IN ADDITION...WARMING AND DRYING IS INDICATED PER
FORECAST SOUNDINGS ABOVE THE MOIST LAYER DURING THE PERIOD. ALL
TOLD...THIS IS A DECENT SETUP FOR FREEZING DRIZZLE AND HAVE
INTRODUCED IT IN THE GRIDS. DURING THE EVENING HOURS...WITH THE
EXCEPTION OF THE PANHANDLE COUNTIES AND FAR NORTHWEST...CONDS WILL
BE FAVORABLE FOR FZDZ. THIS AREA WILL SHRINK EAST INTO THE OVERNIGHT
HOURS AND MORNING PERIOD FOR FRIDAY. BY FRIDAY AFTERNOON...MOSTLY
CLEAR SKIES IN THE CENTRAL AND WEST...AND PARTLY CLOUDY SKIES IN THE
EAST ARE EXPECTED. THIS WILL ALLOW TEMPS TO REACH THE LOWER TO
MIDDLE 30S FRIDAY...EFFECTIVELY ENDING THE FREEZING DRIZZLE THREAT.
ON FRIDAY NIGHT AND SATURDAY...FORECAST SOUNDINGS OVER THE EASTERN
THIRD OF THE FORECAST AREA ARE INDICATIVE OF ANOTHER EPISODE OF
FREEZING DRIZZLE LATE FRIDAY NIGHT INTO SATURDAY MORNING. ATTM...THE
THREAT FOR FREEZING DRIZZLE IS INDICATED ONLY IN THE NAM SOLN AS THE
GFS IS MORE AGGRESSIVE IN PUSHING THE ARCTIC AIRMASS EAST FRIDAY
NIGHT. GIVEN THE MODEL DIFFERENCES...WILL HOLD OFF ON MENTION OF
FREEZING DRIZZLE ATTM. ON SATURDAY...AN UPPER LEVEL DISTURBANCE
ACROSS THE NRN TIER OF STATES...WILL FORCE WARMER AIR INTO THE
FORECAST AREA...FOLLOWED BY A WEAK COOL FRONT SATURDAY NIGHT. LIGHT
WESTERLY WINDS SATURDAY WILL PUSH HIGHS INTO THE LOWER 40S.
SUNDAY THROUGH WEDNESDAY...AS THE UPPER LEVEL SYSTEM PUSHES EAST
MONDAY AND MONDAY NIGHT...THERE WILL BE AN INCREASED THREAT FOR LIGHT
PRECIPITATION IN THE FAR NORTHEAST...ALONG WITH A THREAT FOR
PRECIPITATION ACROSS THE CENTRAL AND NORTHERN ROCKIES...WHICH WILL
BE ENHANCED BY A STRONG UPPER LEVEL JET STREAK. BEYOND MONDAY
NIGHT...A DRY AND COLDER FORECAST IS EXPECTED ACROSS WESTERN AND
NORTH CENTRAL NEBRASKA AS ARCTIC AIR PUSHES SOUTH TUESDAY INTO
WEDNESDAY. ATTM...THE BEST THREAT FOR SNOW WILL BE OFF TO THE WEST
OF THE FORECAST AREA...HOWEVER...WE WILL NEED TO MONITOR NEXT
THURSDAY INTO NEXT WEEKEND AS THE LATEST ECMWF SOLN DIGS A DEEP
TROUGH INTO THE INTERMOUNTAIN WEST BY DAY 10.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 532 PM CST WED DEC 17 2014
CONDITIONS APPEAR FAVORABLE FOR LIFR OVERNIGHT THROUGH 18Z
THURSDAY ACROSS ALL OF WRN/NCNTL NEB. THE ARCTIC HIGH ACROSS THE
CNTL U.S. HAS TRAPPED SUBSTANTIAL LOW LEVEL MOISTURE. SOME DEEPER
MOISTURE ALONG AND EAST OF HIGHWAY 83 IS EXPECTED TO SHIFT EAST
OVERNIGHT AND EXIT THE FCST AREA BY 15Z-18Z AND THIS COULD
ACTUALLY ALLOW FOR DENSE FOG BY MORNING ACROSS ALL OF WRN/NCNTL
NEB.
THE FORECAST FOLLOWS A MIDDLE PATH WITH LIFR/IFR OVERNIGHT IMPROVING
TO IFR/MVFR 15Z-18Z THURSDAY. THE RAP SHOWS DENSE FOG FORMING
ALONG AND WEST OF HIGHWAY 61 BY MORNING AND THIS IS CONSISTENT
WITH A SHALLOWER MOISTURE PROFILE THAN WHAT IS CURRENTLY OVER THE
FCST AREA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...MASEK/JWS
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1144 AM CST TUE DEC 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CST TUE DEC 16 2014
WITH LITTLE TO NO RISK OF PRECIPITATION DURING THESE NEXT 24
HOURS...THE MAIN FORECAST CHALLENGE CENTERS AROUND
TEMPERATURES/SKY COVER...AND THE OBVIOUS AFFECT ONE HAS ON THE
OTHER...ALONG WITH ANY INFLUENCE ON TEMPS FROM SNOW COVER IN
NORTHERN/WESTERN COUNTIES.
STARTING OFF WITH THE HERE AND NOW AS OF 0900Z/3AM...ITS
CERTAINLY BEEN A MUCH QUIETER NIGHT THAN THE PRECEDING ONE...AS
ANY MEASURABLE PRECIP ASSOCIATED WITH THE DEPARTING LOW PRESSURE
SYSTEM IS NOW WELL-EAST INTO EASTERN IA. IN THE MID AND UPPER
LEVELS...WATER VAPOR SATELLITE AND SHORT TERM MODEL DATA CLEARLY
DEPICT THE CENTER OF THE CLOSED 500 MILLIBAR LOW OVER NORTHERN
IL...WHILE UPSTREAM FROM IT...THE LEADING EDGE OF A BROAD
SHORTWAVE RIDGE AND ASSOCIATED HEIGHT RISES IS STARTING TO
OVERSPREAD THE LOCAL AREA...WITH THE RIDGE AXIS GENERALLY ALIGNED
NORTH-SOUTH THROUGH THE ROCKIES. FARTHER WEST...THE NEXT BROAD
TROUGH IS IN THE PROCESS OF COMING ONSHORE THE WEST COAST...WHICH
WILL PROVIDE PLENTY OF CHALLENGES LOCALLY IN THE DAYS 2-4 PERIOD
AS COVERED IN THE LONG TERM SECTION BELOW. AT THE
SURFACE...CERTAINLY THE BIG STORY OVERNIGHT HAS BEEN CONTINUED
FAIRLY STRONG NORTHWEST WINDS...ALTHOUGH THEY ARE ON A SLOW-BUT-
STEADY DOWNWARD TREND AS THE PRESSURE GRADIENT STARTS TO RELAX IN
THE WAKE OF THE DEPARTING 1004MB LOW OVER NORTHERN IL...AND AS A
BROAD RIDGE AXIS CENTERED AT AROUND 1030MB OVER THE DAKOTAS/SOUTH
CENTRAL CANADA STARTS TO EXERT INCREASING INFLUENCE LOCALLY. AS OF
THIS TIME HOWEVER...SUSTAINED SPEEDS OF AT LEAST 20-25 MPH ARE
HANGING ON IN EASTERN ZONES WITH HIGHER GUSTS...AND MORE SO 15-20
MPH IN WESTERN ZONES. EARLIER IN THE NIGHT...THERE WERE LAW
ENFORCEMENT REPORTS OF SOME DICEY TRAVEL CONDITIONS DUE TO SLICK
ROADS/LIMITED BLOWING SNOW IN/NEAR THE FAR NORTHERN CWA COUNTIES
OF VALLEY/GREELEY...BUT FORTUNATELY THE DECREASING SPEEDS SHOULD
AT LEAST IMPROVE THIS SITUATION SLIGHTLY. ACTUALLY THE NUMBER ONE
VERY SHORT-TERM CHALLENGE IS SKY COVER...AS WHILE THE MAJORITY OF
THE CWA REMAINS UNDER A BROAD LOW STRATUS DECK AROUND 1500 FT
AGL...AN AREA OF CLEARING HAS RECENTLY BROKEN OUT OVER SOUTHWEST
COUNTIES. TEMP-WISE...AS SUSPECTED 24 HOURS THE COMBO OF CLOUDS
AND/OR BRISK BREEZES IS HOLDING UP THINGS FAIRLY WELL...AND
ALTHOUGH SOME DROPS COULD YET OCCUR AROUND SUNRISE...THINK THE
MAJORITY OF THE CWA SHOULD HOLD UP NO COLDER THAN THE 17-20 RANGE.
LOOKING FORWARD INTO THE DAYTIME FORECAST AND STARTING WITH THE
MID-UPPER LEVEL SCENE...THE AFOREMENTIONED BROAD RIDGE AXIS
OVERSPREADS THE CENTRAL PLAINS BUT FLATTENS A BIT AS IT DOES SO.
AT THE SURFACE...CERTAINLY THE MOST NOTICEABLE CHANGE FROM MONDAY
WILL BE THE DECREASING NORTHWESTERLY WINDS...AS THE PRESSURE
GRADIENT CONTINUES EASING UP AS THE SOUTHERN EDGE OF THE RIDGE
AXIS CENTERED TO THE NORTH CONTINUES PUSHING SOUTHWARD INTO THE
CENTRAL PLAINS IN THE WAKE OF THE DEPARTING LOW THAT REACHES THE
LAKE HURON AREA BY SUNSET. SPEED-WISE...BY MID-DAY SUSTAINED
SPEEDS SHOULD AVERAGE ONLY AROUND 15 MPH IN EASTERN ZONES...AND NO
MORE THAN 10-15 MPH IN WESTERN COUNTIES...AND BY NIGHTFALL THE
ENTIRE CWA SHOULD BE DOWN TO ONLY 5-10 MPH. AS MENTIONED...SKY
COVER/TEMPS ARE REALLY THE FORECAST CHALLENGE OF THE DAY. MODELS
SUCH AS THE 06Z NAM CLEARLY HOLD ONTO PLENTIFUL LOW LEVEL CLOUD
COVER THROUGH THE ENTIRE DAY WITHIN ROUGHLY THE NORTHEAST 1/2 OF
THE CWA...BUT DO SHOW AT LEAST SEVERAL HOURS OF MOSTLY SUNNY-
PARTLY CLOUDY POTENTIAL OVER MUCH OF THE SOUTHWESTERN 1/2.
ALTHOUGH THE LATEST HRRR LOW LEVEL SKY COVER PRODUCT SPORTS A
SIMILAR THEME...IT SUGGESTS THAT SOME OF THE CLEARING THAT OCCURS
COULD FILL BACK IN AS MORE CLOUDS ADVECT IN FROM THE NORTH-
NORTHWEST. EVEN IF PARTS OF THE CWA DO ENJOY APPRECIABLE CLEARING
AND WELCOMED SUNSHINE THROUGH MUCH OF THE DAY...ESPECIALLY THE
LATER AFTERNOON HOURS SHOULD BRING A GRADUAL INCREASE IN MID-HIGH
CLOUDS STREAMING IN FROM THE WEST IN ASSOCIATION WITH A WEAK/LOW
AMPLITUDE SHORTWAVE TROUGH WELL OUT AHEAD OF THE LARGER WESTERN
TROUGH. SO IN SUMMARY...GENERALLY EXPECT MOSTLY CLOUDY SKIES
NORTHEAST 1/2 TODAY...AND MOSTLY SUNNY-PARTLY CLOUDY
SOUTHWEST ESPECIALLY KS ZONES...BUT SOME VARIATION FROM THIS IS
LIKELY AS WELL. OBVIOUSLY THIS TRICKY SKY COVER WILL WORK IN
CONCERT WITH THE GENERALLY 1-3 INCHES OF SNOW COVER IN PLACE OVER
SEVERAL NORTHERN/WESTERN COUNTIES TO MAKE HIGH TEMPS A BIT
CHALLENGING AS WELL. WITH RAW MET/MAV GUIDANCE LOOKING A BIT TOO
COOL ESPECIALLY IN SOUTHERN ZONES...OPTED TO MAKE ONLY MINOR
TWEAKS TO PREVIOUS FORECAST BY TRYING TO STRIKE SOME KIND OF
BALANCE BETWEEN VARIABLE SNOW COVER AND SKY COVER. THE NET
RESULT...ALTHOUGH NOT OVERLY CONFIDENT...YIELDS ONLY MID-UPPER 20S
WITHIN MANY NORTHERN/WESTERN NEB COUNTIES...MAINLY LOW 30S IN
EASTERN/SOUTHERN NEB ZONES...AND GENERALLY MID 30S IN KS ZONES.
TURNING TO THIS EVENING/TONIGHT...THE MID-UPPER LEVEL PICTURE
FEATURES THE AFOREMENTIONED/RATHER SUBTLE LEAD SHORTWAVE
DISTURBANCE CROSSING OVER THE LOCAL AREA...WHILE MORE ENERGETIC
WAVES REMAIN WELL OFF TO THE WEST-SOUTHWEST. MEANWHILE AT THE
SURFACE...THE RIDGE AXIS WILL SLOWLY EDGE EASTWARD. ALTHOUGH WIND
SPEEDS SHOULD REMAIN LIGHT GENERALLY WELL-UNDER 10 MPH THROUGH THE
ENTIRE NIGHT...DIRECTION WILL GRADUALLY TRANSITION FROM NORTHERLY
TO EASTERLY. DESPITE THE FAIRLY WEAK NATURE OF THE PASSING
DISTURBANCE...MODEL RELATIVE HUMIDITY PROGS DEPICT A FAIRLY DECENT
COVERAGE OF MID-HIGH CLOUD COVER THROUGH THE NIGHT...AND HAVE THE
ENTIRE CWA IN PARTLY TO MOSTLY CLOUDY SKY COVER CATEGORY. WHILE
CONFIDENCE IS FAIRLY HIGH IN A PRECIP-FREE NIGHT (ESPECIALLY
MEASURABLE) AND THE OFFICIAL FORECAST REFLECTS SUCH...WOULD NOT BE
TOTALLY SURPRISED TO SEE A WEST-EAST ORIENTED BAND OF FLURRIES
TRY TO GET GOING LATE IN THE NIGHT MAINLY OVER/NEAR THE NORTHERN
CWA IN RESPONSE TO SOME FAIRLY MODEST ISENTROPIC LIFT/FRONTOGENESIS
FOCUSED IN THE ENTRANCE REGION OF A DEPARTING UPPER JET STREAK.
DESPITE THE LIGHT BREEZES...THE EXPECTED FAIRLY HIGH SKY COVER
SHOULD KEEP TEMPS FROM REALLY FALLING OFF...AND AS A RESULT KEPT
LOW TEMPS GENERALLY 2-4 DEGREES ABOVE A 00Z MET/MAV GUIDANCE
BLEND...AIMING MOST OF THE CWA INTO THE 15-20 RANGE...EXCEPT FOR
COLDER READINGS AROUND 10 FAR NORTH. LASTLY...DESPITE FAIRLY HIGH
VALUES OF FORECAST LOW-LEVEL RELATIVE HUMIDITY...CONFIDENCE WAS
NOT SUFFICIENT ENOUGH IN FOG FORMATION TO INTRODUCE EVEN A PATCHY
MENTION FOR LATE TONIGHT...ALTHOUGH 03Z SREF/06Z NAM VISIBILITY
PROGS SUGGEST THAT MAYBE LOCALIZED POCKETS OF MAINLY THE FAR
WESTERN CWA COULD BEAR WATCHING FOR THIS...ESPECIALLY IF ENOUGH
SNOW MANAGES TO MELT TODAY TO ENHANCE LOW-LEVEL MOISTURE.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 457 AM CST TUE DEC 16 2014
THE BIGGEST CHALLENGE CONTINUES TO BE DETERMINING CHANCES OF
PRECIPITATION...AS WELL AS POTENTIAL TYPE OF PRECIPITATION WEDNESDAY
NIGHT THROUGH THURSDAY NIGHT.
MODELS ARE COMING IN BETTER AGREEMENT WITH A LONGWAVE TROUGH OVER
THE GREAT BASIN EJECTING A LOW-AMPLITUDE WAVE INTO THE SOUTH CENTRAL
PLAINS. THIS WILL BE A FAIRLY QUICK HITTER...DROPPING SOME QUICK
LIGHT SNOW WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING...WITH
POTENTIALLY SOME LINGERING FLURRIES FOR THURSDAY AFTERNOON/NIGHT. AT
TIMES...IT APPEARS THAT WE COULD HAVE A LOSS OF SATURATION IN MID-
LEVELS. THIS IS GENERALLY LOWER THAN THE DENDRITIC GROWTH ZONE.
THERE IS NOT WIDESPREAD AGREEMENT WITH THIS. WAS THINKING ABOUT
STICKING IN POTENTIAL LIGHT FREEZING DRIZZLE FOR THURSDAY
NIGHT...BUT THE WAVE SHOULD BE FAR ENOUGH EAST THAT I HAVE DOUBTS
THAT MUCH OF ANY PRECIPITATION WILL FALL AT ALL. I STUCK IN A SLIGHT
CHANCE OF FLURRIES FOR THURSDAY AFTERNOON/NIGHT...AS THE NAM DOES
ADVERTISE SOME SPARSE NON-MEASURABLE PRECIPITATION...BUT THIS DOES
NOT LOOK LIKELY BY ANY MEANS.
I KEPT PRECIPITATION OUT OF FRIDAY AS THE MAIN WAVE IS TRENDING
FARTHER SOUTH...WITH THE ASSOCIATED ENERGY FAR TOO SOUTH TO GIVE US
A CHANCE OF PRECIPITATION.
THE FORECAST IS DRY FOR THE WEEKEND INTO MONDAY...HOWEVER
PROGRESSIVE WEST/NORTHWEST FLOW MAKES THINGS A BIT UNCERTAIN AS
SMALL WAVES AND PERTURBATIONS MAY NECESSITATE SOME CHANCES OF
PRECIPITATION DOWN THE ROAD...ESPECIALLY TOWARD MONDAY...DEPENDING
ON TIMING AND PLACEMENT OF WAVES/PERTURBATIONS.
THERE WILL BE A SLOW AND STEADY INCREASE OF TEMPERATURES DURING THE
LONG TERM FORECAST...YET REMAINING FAIRLY SEASONABLE.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1140 AM CST TUE DEC 16 2014
A SFC RIDGE OF HIGH PRESSURE WILL SLIDE EAST ACROSS THE
AREA...WHICH WILL RESULT IN DECREASING WINDS TODAY AND EVENTUALLY
LIGHT AND VARIABLE TO EVEN CALM WINDS BY THIS EVENING. A GENTLE
EAST SOUTHEAST BREEZY CAN THEN BE EXPECTED WEDNESDAY MORNING AFTER
THE RIDGE PASSES OFF TO OUR EAST. THE LOW CLOUDS WILL LIKELY HOLD
ON THROUGHOUT THE PERIOD...ALTHOUGH THERE MAY BE SOME BREAKS AT
TIMES. WILL GO WITH PERSISTENCE...WHICH IS SUPPORTED BY THE
FORECAST MODELS AND CALL FOR GENERALLY MVFR CEILINGS THROUGHOUT
THE TAF PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
555 AM CST TUE DEC 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CST TUE DEC 16 2014
WITH LITTLE TO NO RISK OF PRECIPITATION DURING THESE NEXT 24
HOURS...THE MAIN FORECAST CHALLENGE CENTERS AROUND
TEMPERATURES/SKY COVER...AND THE OBVIOUS AFFECT ONE HAS ON THE
OTHER...ALONG WITH ANY INFLUENCE ON TEMPS FROM SNOW COVER IN
NORTHERN/WESTERN COUNTIES.
STARTING OFF WITH THE HERE AND NOW AS OF 0900Z/3AM...ITS
CERTAINLY BEEN A MUCH QUIETER NIGHT THAN THE PRECEDING ONE...AS
ANY MEASURABLE PRECIP ASSOCIATED WITH THE DEPARTING LOW PRESSURE
SYSTEM IS NOW WELL-EAST INTO EASTERN IA. IN THE MID AND UPPER
LEVELS...WATER VAPOR SATELLITE AND SHORT TERM MODEL DATA CLEARLY
DEPICT THE CENTER OF THE CLOSED 500 MILLIBAR LOW OVER NORTHERN
IL...WHILE UPSTREAM FROM IT...THE LEADING EDGE OF A BROAD
SHORTWAVE RIDGE AND ASSOCIATED HEIGHT RISES IS STARTING TO
OVERSPREAD THE LOCAL AREA...WITH THE RIDGE AXIS GENERALLY ALIGNED
NORTH-SOUTH THROUGH THE ROCKIES. FARTHER WEST...THE NEXT BROAD
TROUGH IS IN THE PROCESS OF COMING ONSHORE THE WEST COAST...WHICH
WILL PROVIDE PLENTY OF CHALLENGES LOCALLY IN THE DAYS 2-4 PERIOD
AS COVERED IN THE LONG TERM SECTION BELOW. AT THE
SURFACE...CERTAINLY THE BIG STORY OVERNIGHT HAS BEEN CONTINUED
FAIRLY STRONG NORTHWEST WINDS...ALTHOUGH THEY ARE ON A SLOW-BUT-
STEADY DOWNWARD TREND AS THE PRESSURE GRADIENT STARTS TO RELAX IN
THE WAKE OF THE DEPARTING 1004MB LOW OVER NORTHERN IL...AND AS A
BROAD RIDGE AXIS CENTERED AT AROUND 1030MB OVER THE DAKOTAS/SOUTH
CENTRAL CANADA STARTS TO EXERT INCREASING INFLUENCE LOCALLY. AS OF
THIS TIME HOWEVER...SUSTAINED SPEEDS OF AT LEAST 20-25 MPH ARE
HANGING ON IN EASTERN ZONES WITH HIGHER GUSTS...AND MORE SO 15-20
MPH IN WESTERN ZONES. EARLIER IN THE NIGHT...THERE WERE LAW
ENFORCEMENT REPORTS OF SOME DICEY TRAVEL CONDITIONS DUE TO SLICK
ROADS/LIMITED BLOWING SNOW IN/NEAR THE FAR NORTHERN CWA COUNTIES
OF VALLEY/GREELEY...BUT FORTUNATELY THE DECREASING SPEEDS SHOULD
AT LEAST IMPROVE THIS SITUATION SLIGHTLY. ACTUALLY THE NUMBER ONE
VERY SHORT-TERM CHALLENGE IS SKY COVER...AS WHILE THE MAJORITY OF
THE CWA REMAINS UNDER A BROAD LOW STRATUS DECK AROUND 1500 FT
AGL...AN AREA OF CLEARING HAS RECENTLY BROKEN OUT OVER SOUTHWEST
COUNTIES. TEMP-WISE...AS SUSPECTED 24 HOURS THE COMBO OF CLOUDS
AND/OR BRISK BREEZES IS HOLDING UP THINGS FAIRLY WELL...AND
ALTHOUGH SOME DROPS COULD YET OCCUR AROUND SUNRISE...THINK THE
MAJORITY OF THE CWA SHOULD HOLD UP NO COLDER THAN THE 17-20 RANGE.
LOOKING FORWARD INTO THE DAYTIME FORECAST AND STARTING WITH THE
MID-UPPER LEVEL SCENE...THE AFOREMENTIONED BROAD RIDGE AXIS
OVERSPREADS THE CENTRAL PLAINS BUT FLATTENS A BIT AS IT DOES SO.
AT THE SURFACE...CERTAINLY THE MOST NOTICEABLE CHANGE FROM MONDAY
WILL BE THE DECREASING NORTHWESTERLY WINDS...AS THE PRESSURE
GRADIENT CONTINUES EASING UP AS THE SOUTHERN EDGE OF THE RIDGE
AXIS CENTERED TO THE NORTH CONTINUES PUSHING SOUTHWARD INTO THE
CENTRAL PLAINS IN THE WAKE OF THE DEPARTING LOW THAT REACHES THE
LAKE HURON AREA BY SUNSET. SPEED-WISE...BY MID-DAY SUSTAINED
SPEEDS SHOULD AVERAGE ONLY AROUND 15 MPH IN EASTERN ZONES...AND NO
MORE THAN 10-15 MPH IN WESTERN COUNTIES...AND BY NIGHTFALL THE
ENTIRE CWA SHOULD BE DOWN TO ONLY 5-10 MPH. AS MENTIONED...SKY
COVER/TEMPS ARE REALLY THE FORECAST CHALLENGE OF THE DAY. MODELS
SUCH AS THE 06Z NAM CLEARLY HOLD ONTO PLENTIFUL LOW LEVEL CLOUD
COVER THROUGH THE ENTIRE DAY WITHIN ROUGHLY THE NORTHEAST 1/2 OF
THE CWA...BUT DO SHOW AT LEAST SEVERAL HOURS OF MOSTLY SUNNY-
PARTLY CLOUDY POTENTIAL OVER MUCH OF THE SOUTHWESTERN 1/2.
ALTHOUGH THE LATEST HRRR LOW LEVEL SKY COVER PRODUCT SPORTS A
SIMILAR THEME...IT SUGGESTS THAT SOME OF THE CLEARING THAT OCCURS
COULD FILL BACK IN AS MORE CLOUDS ADVECT IN FROM THE NORTH-
NORTHWEST. EVEN IF PARTS OF THE CWA DO ENJOY APPRECIABLE CLEARING
AND WELCOMED SUNSHINE THROUGH MUCH OF THE DAY...ESPECIALLY THE
LATER AFTERNOON HOURS SHOULD BRING A GRADUAL INCREASE IN MID-HIGH
CLOUDS STREAMING IN FROM THE WEST IN ASSOCIATION WITH A WEAK/LOW
AMPLITUDE SHORTWAVE TROUGH WELL OUT AHEAD OF THE LARGER WESTERN
TROUGH. SO IN SUMMARY...GENERALLY EXPECT MOSTLY CLOUDY SKIES
NORTHEAST 1/2 TODAY...AND MOSTLY SUNNY-PARTLY CLOUDY
SOUTHWEST ESPECIALLY KS ZONES...BUT SOME VARIATION FROM THIS IS
LIKELY AS WELL. OBVIOUSLY THIS TRICKY SKY COVER WILL WORK IN
CONCERT WITH THE GENERALLY 1-3 INCHES OF SNOW COVER IN PLACE OVER
SEVERAL NORTHERN/WESTERN COUNTIES TO MAKE HIGH TEMPS A BIT
CHALLENGING AS WELL. WITH RAW MET/MAV GUIDANCE LOOKING A BIT TOO
COOL ESPECIALLY IN SOUTHERN ZONES...OPTED TO MAKE ONLY MINOR
TWEAKS TO PREVIOUS FORECAST BY TRYING TO STRIKE SOME KIND OF
BALANCE BETWEEN VARIABLE SNOW COVER AND SKY COVER. THE NET
RESULT...ALTHOUGH NOT OVERLY CONFIDENT...YIELDS ONLY MID-UPPER 20S
WITHIN MANY NORTHERN/WESTERN NEB COUNTIES...MAINLY LOW 30S IN
EASTERN/SOUTHERN NEB ZONES...AND GENERALLY MID 30S IN KS ZONES.
TURNING TO THIS EVENING/TONIGHT...THE MID-UPPER LEVEL PICTURE
FEATURES THE AFOREMENTIONED/RATHER SUBTLE LEAD SHORTWAVE
DISTURBANCE CROSSING OVER THE LOCAL AREA...WHILE MORE ENERGETIC
WAVES REMAIN WELL OFF TO THE WEST-SOUTHWEST. MEANWHILE AT THE
SURFACE...THE RIDGE AXIS WILL SLOWLY EDGE EASTWARD. ALTHOUGH WIND
SPEEDS SHOULD REMAIN LIGHT GENERALLY WELL-UNDER 10 MPH THROUGH THE
ENTIRE NIGHT...DIRECTION WILL GRADUALLY TRANSITION FROM NORTHERLY
TO EASTERLY. DESPITE THE FAIRLY WEAK NATURE OF THE PASSING
DISTURBANCE...MODEL RELATIVE HUMIDITY PROGS DEPICT A FAIRLY DECENT
COVERAGE OF MID-HIGH CLOUD COVER THROUGH THE NIGHT...AND HAVE THE
ENTIRE CWA IN PARTLY TO MOSTLY CLOUDY SKY COVER CATEGORY. WHILE
CONFIDENCE IS FAIRLY HIGH IN A PRECIP-FREE NIGHT (ESPECIALLY
MEASURABLE) AND THE OFFICIAL FORECAST REFLECTS SUCH...WOULD NOT BE
TOTALLY SURPRISED TO SEE A WEST-EAST ORIENTED BAND OF FLURRIES
TRY TO GET GOING LATE IN THE NIGHT MAINLY OVER/NEAR THE NORTHERN
CWA IN RESPONSE TO SOME FAIRLY MODEST ISENTROPIC LIFT/FRONTOGENESIS
FOCUSED IN THE ENTRANCE REGION OF A DEPARTING UPPER JET STREAK.
DESPITE THE LIGHT BREEZES...THE EXPECTED FAIRLY HIGH SKY COVER
SHOULD KEEP TEMPS FROM REALLY FALLING OFF...AND AS A RESULT KEPT
LOW TEMPS GENERALLY 2-4 DEGREES ABOVE A 00Z MET/MAV GUIDANCE
BLEND...AIMING MOST OF THE CWA INTO THE 15-20 RANGE...EXCEPT FOR
COLDER READINGS AROUND 10 FAR NORTH. LASTLY...DESPITE FAIRLY HIGH
VALUES OF FORECAST LOW-LEVEL RELATIVE HUMIDITY...CONFIDENCE WAS
NOT SUFFICIENT ENOUGH IN FOG FORMATION TO INTRODUCE EVEN A PATCHY
MENTION FOR LATE TONIGHT...ALTHOUGH 03Z SREF/06Z NAM VISIBILITY
PROGS SUGGEST THAT MAYBE LOCALIZED POCKETS OF MAINLY THE FAR
WESTERN CWA COULD BEAR WATCHING FOR THIS...ESPECIALLY IF ENOUGH
SNOW MANAGES TO MELT TODAY TO ENHANCE LOW-LEVEL MOISTURE.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 457 AM CST TUE DEC 16 2014
THE BIGGEST CHALLENGE CONTINUES TO BE DETERMINING CHANCES OF
PRECIPITATION...AS WELL AS POTENTIAL TYPE OF PRECIPITATION WEDNESDAY
NIGHT THROUGH THURSDAY NIGHT.
MODELS ARE COMING IN BETTER AGREEMENT WITH A LONGWAVE TROUGH OVER
THE GREAT BASIN EJECTING A LOW-AMPLITUDE WAVE INTO THE SOUTH CENTRAL
PLAINS. THIS WILL BE A FAIRLY QUICK HITTER...DROPPING SOME QUICK
LIGHT SNOW WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING...WITH
POTENTIALLY SOME LINGERING FLURRIES FOR THURSDAY AFTERNOON/NIGHT. AT
TIMES...IT APPEARS THAT WE COULD HAVE A LOSS OF SATURATION IN MID-
LEVELS. THIS IS GENERALLY LOWER THAN THE DENDRITIC GROWTH ZONE.
THERE IS NOT WIDESPREAD AGREEMENT WITH THIS. WAS THINKING ABOUT
STICKING IN POTENTIAL LIGHT FREEZING DRIZZLE FOR THURSDAY
NIGHT...BUT THE WAVE SHOULD BE FAR ENOUGH EAST THAT I HAVE DOUBTS
THAT MUCH OF ANY PRECIPITATION WILL FALL AT ALL. I STUCK IN A SLIGHT
CHANCE OF FLURRIES FOR THURSDAY AFTERNOON/NIGHT...AS THE NAM DOES
ADVERTISE SOME SPARSE NON-MEASURABLE PRECIPITATION...BUT THIS DOES
NOT LOOK LIKELY BY ANY MEANS.
I KEPT PRECIPITATION OUT OF FRIDAY AS THE MAIN WAVE IS TRENDING
FARTHER SOUTH...WITH THE ASSOCIATED ENERGY FAR TOO SOUTH TO GIVE US
A CHANCE OF PRECIPITATION.
THE FORECAST IS DRY FOR THE WEEKEND INTO MONDAY...HOWEVER
PROGRESSIVE WEST/NORTHWEST FLOW MAKES THINGS A BIT UNCERTAIN AS
SMALL WAVES AND PERTURBATIONS MAY NECESSITATE SOME CHANCES OF
PRECIPITATION DOWN THE ROAD...ESPECIALLY TOWARD MONDAY...DEPENDING
ON TIMING AND PLACEMENT OF WAVES/PERTURBATIONS.
THERE WILL BE A SLOW AND STEADY INCREASE OF TEMPERATURES DURING THE
LONG TERM FORECAST...YET REMAINING FAIRLY SEASONABLE.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 555 AM CST TUE DEC 16 2014
ALTHOUGH CONFIDENCE IS RATHER HIGH IN BOTH WIND SPEEDS/DIRECTION
AND THE FACT THAT VFR VISIBILITY SHOULD PREVAIL...UNFORTUNATELY
THE SAME QUESTION MARKS REGARDING CEILING TRENDS
CONTINUE...INVOLVING WHEN A RETURN TO VFR MIGHT OCCUR FROM THE
PRESENT MVFR STRATUS SITUATION AND IF SO FOR HOW LONG. GIVEN THAT
THE LAST THREE TAF ISSUANCES HAVE JUST CONTINUED TO DELAY THE
RETURN OF VFR CEILING...OPTED TO SIMPLY "SELL OUT" TO PERSISTENCE
THIS TIME AROUND AND MAINTAIN MVFR THROUGH THE ENTIRE PERIOD AND
BE PLEASANTLY SURPRISED IF VFR RETURNS AT SOME POINT. NO MATTER
WHAT CEILINGS DO...CONFIDENCE IS HIGH IN A PRECIPITATION-FREE
PERIOD. WIND-WISE...DECREASING SPEEDS WILL BE THE MAIN STORY
THROUGH THE PERIOD. RIGHT AWAY THIS MORNING...GUST POTENTIAL OF AT
LEAST 20-25KT WILL CONTINUE...BUT BY MID-DAY PEAK GUSTS SHOULD
EASE DOWN INTO THE 15-20KT RANGE...WITH FAIRLY LIGHT BREEZES THEN
IN PLACE FOR THIS EVENING-TONIGHT AS DIRECTION CHANGES FROM
NORTHERLY TO EASTERLY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
501 AM CST TUE DEC 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CST TUE DEC 16 2014
WITH LITTLE TO NO RISK OF PRECIPITATION DURING THESE NEXT 24
HOURS...THE MAIN FORECAST CHALLENGE CENTERS AROUND
TEMPERATURES/SKY COVER...AND THE OBVIOUS AFFECT ONE HAS ON THE
OTHER...ALONG WITH ANY INFLUENCE ON TEMPS FROM SNOW COVER IN
NORTHERN/WESTERN COUNTIES.
STARTING OFF WITH THE HERE AND NOW AS OF 0900Z/3AM...ITS
CERTAINLY BEEN A MUCH QUIETER NIGHT THAN THE PRECEDING ONE...AS
ANY MEASURABLE PRECIP ASSOCIATED WITH THE DEPARTING LOW PRESSURE
SYSTEM IS NOW WELL-EAST INTO EASTERN IA. IN THE MID AND UPPER
LEVELS...WATER VAPOR SATELLITE AND SHORT TERM MODEL DATA CLEARLY
DEPICT THE CENTER OF THE CLOSED 500 MILLIBAR LOW OVER NORTHERN
IL...WHILE UPSTREAM FROM IT...THE LEADING EDGE OF A BROAD
SHORTWAVE RIDGE AND ASSOCIATED HEIGHT RISES IS STARTING TO
OVERSPREAD THE LOCAL AREA...WITH THE RIDGE AXIS GENERALLY ALIGNED
NORTH-SOUTH THROUGH THE ROCKIES. FARTHER WEST...THE NEXT BROAD
TROUGH IS IN THE PROCESS OF COMING ONSHORE THE WEST COAST...WHICH
WILL PROVIDE PLENTY OF CHALLENGES LOCALLY IN THE DAYS 2-4 PERIOD
AS COVERED IN THE LONG TERM SECTION BELOW. AT THE
SURFACE...CERTAINLY THE BIG STORY OVERNIGHT HAS BEEN CONTINUED
FAIRLY STRONG NORTHWEST WINDS...ALTHOUGH THEY ARE ON A SLOW-BUT-
STEADY DOWNWARD TREND AS THE PRESSURE GRADIENT STARTS TO RELAX IN
THE WAKE OF THE DEPARTING 1004MB LOW OVER NORTHERN IL...AND AS A
BROAD RIDGE AXIS CENTERED AT AROUND 1030MB OVER THE DAKOTAS/SOUTH
CENTRAL CANADA STARTS TO EXERT INCREASING INFLUENCE LOCALLY. AS OF
THIS TIME HOWEVER...SUSTAINED SPEEDS OF AT LEAST 20-25 MPH ARE
HANGING ON IN EASTERN ZONES WITH HIGHER GUSTS...AND MORE SO 15-20
MPH IN WESTERN ZONES. EARLIER IN THE NIGHT...THERE WERE LAW
ENFORCEMENT REPORTS OF SOME DICEY TRAVEL CONDITIONS DUE TO SLICK
ROADS/LIMITED BLOWING SNOW IN/NEAR THE FAR NORTHERN CWA COUNTIES
OF VALLEY/GREELEY...BUT FORTUNATELY THE DECREASING SPEEDS SHOULD
AT LEAST IMPROVE THIS SITUATION SLIGHTLY. ACTUALLY THE NUMBER ONE
VERY SHORT-TERM CHALLENGE IS SKY COVER...AS WHILE THE MAJORITY OF
THE CWA REMAINS UNDER A BROAD LOW STRATUS DECK AROUND 1500 FT
AGL...AN AREA OF CLEARING HAS RECENTLY BROKEN OUT OVER SOUTHWEST
COUNTIES. TEMP-WISE...AS SUSPECTED 24 HOURS THE COMBO OF CLOUDS
AND/OR BRISK BREEZES IS HOLDING UP THINGS FAIRLY WELL...AND
ALTHOUGH SOME DROPS COULD YET OCCUR AROUND SUNRISE...THINK THE
MAJORITY OF THE CWA SHOULD HOLD UP NO COLDER THAN THE 17-20 RANGE.
LOOKING FORWARD INTO THE DAYTIME FORECAST AND STARTING WITH THE
MID-UPPER LEVEL SCENE...THE AFOREMENTIONED BROAD RIDGE AXIS
OVERSPREADS THE CENTRAL PLAINS BUT FLATTENS A BIT AS IT DOES SO.
AT THE SURFACE...CERTAINLY THE MOST NOTICEABLE CHANGE FROM MONDAY
WILL BE THE DECREASING NORTHWESTERLY WINDS...AS THE PRESSURE
GRADIENT CONTINUES EASING UP AS THE SOUTHERN EDGE OF THE RIDGE
AXIS CENTERED TO THE NORTH CONTINUES PUSHING SOUTHWARD INTO THE
CENTRAL PLAINS IN THE WAKE OF THE DEPARTING LOW THAT REACHES THE
LAKE HURON AREA BY SUNSET. SPEED-WISE...BY MID-DAY SUSTAINED
SPEEDS SHOULD AVERAGE ONLY AROUND 15 MPH IN EASTERN ZONES...AND NO
MORE THAN 10-15 MPH IN WESTERN COUNTIES...AND BY NIGHTFALL THE
ENTIRE CWA SHOULD BE DOWN TO ONLY 5-10 MPH. AS MENTIONED...SKY
COVER/TEMPS ARE REALLY THE FORECAST CHALLENGE OF THE DAY. MODELS
SUCH AS THE 06Z NAM CLEARLY HOLD ONTO PLENTIFUL LOW LEVEL CLOUD
COVER THROUGH THE ENTIRE DAY WITHIN ROUGHLY THE NORTHEAST 1/2 OF
THE CWA...BUT DO SHOW AT LEAST SEVERAL HOURS OF MOSTLY SUNNY-
PARTLY CLOUDY POTENTIAL OVER MUCH OF THE SOUTHWESTERN 1/2.
ALTHOUGH THE LATEST HRRR LOW LEVEL SKY COVER PRODUCT SPORTS A
SIMILAR THEME...IT SUGGESTS THAT SOME OF THE CLEARING THAT OCCURS
COULD FILL BACK IN AS MORE CLOUDS ADVECT IN FROM THE NORTH-
NORTHWEST. EVEN IF PARTS OF THE CWA DO ENJOY APPRECIABLE CLEARING
AND WELCOMED SUNSHINE THROUGH MUCH OF THE DAY...ESPECIALLY THE
LATER AFTERNOON HOURS SHOULD BRING A GRADUAL INCREASE IN MID-HIGH
CLOUDS STREAMING IN FROM THE WEST IN ASSOCIATION WITH A WEAK/LOW
AMPLITUDE SHORTWAVE TROUGH WELL OUT AHEAD OF THE LARGER WESTERN
TROUGH. SO IN SUMMARY...GENERALLY EXPECT MOSTLY CLOUDY SKIES
NORTHEAST 1/2 TODAY...AND MOSTLY SUNNY-PARTLY CLOUDY
SOUTHWEST ESPECIALLY KS ZONES...BUT SOME VARIATION FROM THIS IS
LIKELY AS WELL. OBVIOUSLY THIS TRICKY SKY COVER WILL WORK IN
CONCERT WITH THE GENERALLY 1-3 INCHES OF SNOW COVER IN PLACE OVER
SEVERAL NORTHERN/WESTERN COUNTIES TO MAKE HIGH TEMPS A BIT
CHALLENGING AS WELL. WITH RAW MET/MAV GUIDANCE LOOKING A BIT TOO
COOL ESPECIALLY IN SOUTHERN ZONES...OPTED TO MAKE ONLY MINOR
TWEAKS TO PREVIOUS FORECAST BY TRYING TO STRIKE SOME KIND OF
BALANCE BETWEEN VARIABLE SNOW COVER AND SKY COVER. THE NET
RESULT...ALTHOUGH NOT OVERLY CONFIDENT...YIELDS ONLY MID-UPPER 20S
WITHIN MANY NORTHERN/WESTERN NEB COUNTIES...MAINLY LOW 30S IN
EASTERN/SOUTHERN NEB ZONES...AND GENERALLY MID 30S IN KS ZONES.
TURNING TO THIS EVENING/TONIGHT...THE MID-UPPER LEVEL PICTURE
FEATURES THE AFOREMENTIONED/RATHER SUBTLE LEAD SHORTWAVE
DISTURBANCE CROSSING OVER THE LOCAL AREA...WHILE MORE ENERGETIC
WAVES REMAIN WELL OFF TO THE WEST-SOUTHWEST. MEANWHILE AT THE
SURFACE...THE RIDGE AXIS WILL SLOWLY EDGE EASTWARD. ALTHOUGH WIND
SPEEDS SHOULD REMAIN LIGHT GENERALLY WELL-UNDER 10 MPH THROUGH THE
ENTIRE NIGHT...DIRECTION WILL GRADUALLY TRANSITION FROM NORTHERLY
TO EASTERLY. DESPITE THE FAIRLY WEAK NATURE OF THE PASSING
DISTURBANCE...MODEL RELATIVE HUMIDITY PROGS DEPICT A FAIRLY DECENT
COVERAGE OF MID-HIGH CLOUD COVER THROUGH THE NIGHT...AND HAVE THE
ENTIRE CWA IN PARTLY TO MOSTLY CLOUDY SKY COVER CATEGORY. WHILE
CONFIDENCE IS FAIRLY HIGH IN A PRECIP-FREE NIGHT (ESPECIALLY
MEASURABLE) AND THE OFFICIAL FORECAST REFLECTS SUCH...WOULD NOT BE
TOTALLY SURPRISED TO SEE A WEST-EAST ORIENTED BAND OF FLURRIES
TRY TO GET GOING LATE IN THE NIGHT MAINLY OVER/NEAR THE NORTHERN
CWA IN RESPONSE TO SOME FAIRLY MODEST ISENTROPIC LIFT/FRONTOGENESIS
FOCUSED IN THE ENTRANCE REGION OF A DEPARTING UPPER JET STREAK.
DESPITE THE LIGHT BREEZES...THE EXPECTED FAIRLY HIGH SKY COVER
SHOULD KEEP TEMPS FROM REALLY FALLING OFF...AND AS A RESULT KEPT
LOW TEMPS GENERALLY 2-4 DEGREES ABOVE A 00Z MET/MAV GUIDANCE
BLEND...AIMING MOST OF THE CWA INTO THE 15-20 RANGE...EXCEPT FOR
COLDER READINGS AROUND 10 FAR NORTH. LASTLY...DESPITE FAIRLY HIGH
VALUES OF FORECAST LOW-LEVEL RELATIVE HUMIDITY...CONFIDENCE WAS
NOT SUFFICIENT ENOUGH IN FOG FORMATION TO INTRODUCE EVEN A PATCHY
MENTION FOR LATE TONIGHT...ALTHOUGH 03Z SREF/06Z NAM VISIBILITY
PROGS SUGGEST THAT MAYBE LOCALIZED POCKETS OF MAINLY THE FAR
WESTERN CWA COULD BEAR WATCHING FOR THIS...ESPECIALLY IF ENOUGH
SNOW MANAGES TO MELT TODAY TO ENHANCE LOW-LEVEL MOISTURE.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 457 AM CST TUE DEC 16 2014
THE BIGGEST CHALLENGE CONTINUES TO BE DETERMINING CHANCES OF
PRECIPITATION...AS WELL AS POTENTIAL TYPE OF PRECIPITATION WEDNESDAY
NIGHT THROUGH THURSDAY NIGHT.
MODELS ARE COMING IN BETTER AGREEMENT WITH A LONGWAVE TROUGH OVER
THE GREAT BASIN EJECTING A LOW-AMPLITUDE WAVE INTO THE SOUTH CENTRAL
PLAINS. THIS WILL BE A FAIRLY QUICK HITTER...DROPPING SOME QUICK
LIGHT SNOW WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING...WITH
POTENTIALLY SOME LINGERING FLURRIES FOR THURSDAY AFTERNOON/NIGHT. AT
TIMES...IT APPEARS THAT WE COULD HAVE A LOSS OF SATURATION IN MID-
LEVELS. THIS IS GENERALLY LOWER THAN THE DENDRITIC GROWTH ZONE.
THERE IS NOT WIDESPREAD AGREEMENT WITH THIS. WAS THINKING ABOUT
STICKING IN POTENTIAL LIGHT FREEZING DRIZZLE FOR THURSDAY
NIGHT...BUT THE WAVE SHOULD BE FAR ENOUGH EAST THAT I HAVE DOUBTS
THAT MUCH OF ANY PRECIPITATION WILL FALL AT ALL. I STUCK IN A SLIGHT
CHANCE OF FLURRIES FOR THURSDAY AFTERNOON/NIGHT...AS THE NAM DOES
ADVERTISE SOME SPARSE NON-MEASURABLE PRECIPITATION...BUT THIS DOES
NOT LOOK LIKELY BY ANY MEANS.
I KEPT PRECIPITATION OUT OF FRIDAY AS THE MAIN WAVE IS TRENDING
FARTHER SOUTH...WITH THE ASSOCIATED ENERGY FAR TOO SOUTH TO GIVE US
A CHANCE OF PRECIPITATION.
THE FORECAST IS DRY FOR THE WEEKEND INTO MONDAY...HOWEVER
PROGRESSIVE WEST/NORTHWEST FLOW MAKES THINGS A BIT UNCERTAIN AS
SMALL WAVES AND PERTURBATIONS MAY NECESSITATE SOME CHANCES OF
PRECIPITATION DOWN THE ROAD...ESPECIALLY TOWARD MONDAY...DEPENDING
ON TIMING AND PLACEMENT OF WAVES/PERTURBATIONS.
THERE WILL BE A SLOW AND STEADY INCREASE OF TEMPERATURES DURING THE
LONG TERM FORECAST...YET REMAINING FAIRLY SEASONABLE.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1208 AM CST TUE DEC 16 2014
ALTHOUGH CONFIDENCE IS RATHER HIGH IN BOTH WIND SPEEDS/DIRECTION
AND THE FACT THAT VFR VISIBILITY SHOULD PREVAIL...UNFORTUNATELY
THERE ARE SOME QUESTION MARKS REGARDING CEILING TRENDS...INVOLVING
BOTH WHEN A RETURN TO VFR MIGHT OCCUR AND IF SO FOR HOW LONG. IN
SHORT...OPTED TO ERR A BIT MORE ON THE CAUTIOUS/PESSIMISTIC SIDE
VERSUS PREVIOUS TAF ISSUANCE AND EXTEND AN MVFR CEILING THROUGH
18Z...WITH SOME MODELS/GUIDANCE SUGGESTING THIS MAY BE TOO
LONG...WHILE OTHERS SUGGEST IT MAY NOT BE LONG ENOUGH WITH THE
POTENTIAL FOR MVFR THROUGHOUT THE ENTIRE PERIOD. SO FOR NOW AM
JUST PLAYING A MIDDLE-GROUND. NO MATTER WHAT CEILINGS
DO...CONFIDENCE IS HIGH IN A PRECIPITATION-FREE PERIOD. WIND-
WISE...THINGS START OUT QUITE BRISK EARLY THIS MORNING WITH
SEVERAL MORE HOURS OF NORTHWESTERLY GUST POTENTIAL TO AROUND 30KT
POSSIBLE...ALTHOUGH A SLOW-BUT-STEADY DECREASING TREND WILL TAKE
PLACE DURING THE PERIOD WITH GUST POTENTIAL BY MID-DAY EASING
BELOW 20KT...AND IN FACT FAIRLY LIGHT BREEZES IN PLACE BY TUESDAY
EVENING AS HIGH PRESSURE SETTLES IN.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
334 AM CST TUE DEC 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CST TUE DEC 16 2014
WITH LITTLE TO NO RISK OF PRECIPITATION DURING THESE NEXT 24
HOURS...THE MAIN FORECAST CHALLENGE CENTERS AROUND
TEMPERATURES/SKY COVER...AND THE OBVIOUS AFFECT ONE HAS ON THE
OTHER...ALONG WITH ANY INFLUENCE ON TEMPS FROM SNOW COVER IN
NORTHERN/WESTERN COUNTIES.
STARTING OFF WITH THE HERE AND NOW AS OF 0900Z/3AM...ITS
CERTAINLY BEEN A MUCH QUIETER NIGHT THAN THE PRECEDING ONE...AS
ANY MEASURABLE PRECIP ASSOCIATED WITH THE DEPARTING LOW PRESSURE
SYSTEM IS NOW WELL-EAST INTO EASTERN IA. IN THE MID AND UPPER
LEVELS...WATER VAPOR SATELLITE AND SHORT TERM MODEL DATA CLEARLY
DEPICT THE CENTER OF THE CLOSED 500 MILLIBAR LOW OVER NORTHERN
IL...WHILE UPSTREAM FROM IT...THE LEADING EDGE OF A BROAD
SHORTWAVE RIDGE AND ASSOCIATED HEIGHT RISES IS STARTING TO
OVERSPREAD THE LOCAL AREA...WITH THE RIDGE AXIS GENERALLY ALIGNED
NORTH-SOUTH THROUGH THE ROCKIES. FARTHER WEST...THE NEXT BROAD
TROUGH IS IN THE PROCESS OF COMING ONSHORE THE WEST COAST...WHICH
WILL PROVIDE PLENTY OF CHALLENGES LOCALLY IN THE DAYS 2-4 PERIOD
AS COVERED IN THE LONG TERM SECTION BELOW. AT THE
SURFACE...CERTAINLY THE BIG STORY OVERNIGHT HAS BEEN CONTINUED
FAIRLY STRONG NORTHWEST WINDS...ALTHOUGH THEY ARE ON A SLOW-BUT-
STEADY DOWNWARD TREND AS THE PRESSURE GRADIENT STARTS TO RELAX IN
THE WAKE OF THE DEPARTING 1004MB LOW OVER NORTHERN IL...AND AS A
BROAD RIDGE AXIS CENTERED AT AROUND 1030MB OVER THE DAKOTAS/SOUTH
CENTRAL CANADA STARTS TO EXERT INCREASING INFLUENCE LOCALLY. AS OF
THIS TIME HOWEVER...SUSTAINED SPEEDS OF AT LEAST 20-25 MPH ARE
HANGING ON IN EASTERN ZONES WITH HIGHER GUSTS...AND MORE SO 15-20
MPH IN WESTERN ZONES. EARLIER IN THE NIGHT...THERE WERE LAW
ENFORCEMENT REPORTS OF SOME DICEY TRAVEL CONDITIONS DUE TO SLICK
ROADS/LIMITED BLOWING SNOW IN/NEAR THE FAR NORTHERN CWA COUNTIES
OF VALLEY/GREELEY...BUT FORTUNATELY THE DECREASING SPEEDS SHOULD
AT LEAST IMPROVE THIS SITUATION SLIGHTLY. ACTUALLY THE NUMBER ONE
VERY SHORT-TERM CHALLENGE IS SKY COVER...AS WHILE THE MAJORITY OF
THE CWA REMAINS UNDER A BROAD LOW STRATUS DECK AROUND 1500 FT
AGL...AN AREA OF CLEARING HAS RECENTLY BROKEN OUT OVER SOUTHWEST
COUNTIES. TEMP-WISE...AS SUSPECTED 24 HOURS THE COMBO OF CLOUDS
AND/OR BRISK BREEZES IS HOLDING UP THINGS FAIRLY WELL...AND
ALTHOUGH SOME DROPS COULD YET OCCUR AROUND SUNRISE...THINK THE
MAJORITY OF THE CWA SHOULD HOLD UP NO COLDER THAN THE 17-20 RANGE.
LOOKING FORWARD INTO THE DAYTIME FORECAST AND STARTING WITH THE
MID-UPPER LEVEL SCENE...THE AFOREMENTIONED BROAD RIDGE AXIS
OVERSPREADS THE CENTRAL PLAINS BUT FLATTENS A BIT AS IT DOES SO.
AT THE SURFACE...CERTAINLY THE MOST NOTICEABLE CHANGE FROM MONDAY
WILL BE THE DECREASING NORTHWESTERLY WINDS...AS THE PRESSURE
GRADIENT CONTINUES EASING UP AS THE SOUTHERN EDGE OF THE RIDGE
AXIS CENTERED TO THE NORTH CONTINUES PUSHING SOUTHWARD INTO THE
CENTRAL PLAINS IN THE WAKE OF THE DEPARTING LOW THAT REACHES THE
LAKE HURON AREA BY SUNSET. SPEED-WISE...BY MID-DAY SUSTAINED
SPEEDS SHOULD AVERAGE ONLY AROUND 15 MPH IN EASTERN ZONES...AND NO
MORE THAN 10-15 MPH IN WESTERN COUNTIES...AND BY NIGHTFALL THE
ENTIRE CWA SHOULD BE DOWN TO ONLY 5-10 MPH. AS MENTIONED...SKY
COVER/TEMPS ARE REALLY THE FORECAST CHALLENGE OF THE DAY. MODELS
SUCH AS THE 06Z NAM CLEARLY HOLD ONTO PLENTIFUL LOW LEVEL CLOUD
COVER THROUGH THE ENTIRE DAY WITHIN ROUGHLY THE NORTHEAST 1/2 OF
THE CWA...BUT DO SHOW AT LEAST SEVERAL HOURS OF MOSTLY SUNNY-
PARTLY CLOUDY POTENTIAL OVER MUCH OF THE SOUTHWESTERN 1/2.
ALTHOUGH THE LATEST HRRR LOW LEVEL SKY COVER PRODUCT SPORTS A
SIMILAR THEME...IT SUGGESTS THAT SOME OF THE CLEARING THAT OCCURS
COULD FILL BACK IN AS MORE CLOUDS ADVECT IN FROM THE NORTH-
NORTHWEST. EVEN IF PARTS OF THE CWA DO ENJOY APPRECIABLE CLEARING
AND WELCOMED SUNSHINE THROUGH MUCH OF THE DAY...ESPECIALLY THE
LATER AFTERNOON HOURS SHOULD BRING A GRADUAL INCREASE IN MID-HIGH
CLOUDS STREAMING IN FROM THE WEST IN ASSOCIATION WITH A WEAK/LOW
AMPLITUDE SHORTWAVE TROUGH WELL OUT AHEAD OF THE LARGER WESTERN
TROUGH. SO IN SUMMARY...GENERALLY EXPECT MOSTLY CLOUDY SKIES
NORTHEAST 1/2 TODAY...AND MOSTLY SUNNY-PARTLY CLOUDY
SOUTHWEST ESPECIALLY KS ZONES...BUT SOME VARIATION FROM THIS IS
LIKELY AS WELL. OBVIOUSLY THIS TRICKY SKY COVER WILL WORK IN
CONCERT WITH THE GENERALLY 1-3 INCHES OF SNOW COVER IN PLACE OVER
SEVERAL NORTHERN/WESTERN COUNTIES TO MAKE HIGH TEMPS A BIT
CHALLENGING AS WELL. WITH RAW MET/MAV GUIDANCE LOOKING A BIT TOO
COOL ESPECIALLY IN SOUTHERN ZONES...OPTED TO MAKE ONLY MINOR
TWEAKS TO PREVIOUS FORECAST BY TRYING TO STRIKE SOME KIND OF
BALANCE BETWEEN VARIABLE SNOW COVER AND SKY COVER. THE NET
RESULT...ALTHOUGH NOT OVERLY CONFIDENT...YIELDS ONLY MID-UPPER 20S
WITHIN MANY NORTHERN/WESTERN NEB COUNTIES...MAINLY LOW 30S IN
EASTERN/SOUTHERN NEB ZONES...AND GENERALLY MID 30S IN KS ZONES.
TURNING TO THIS EVENING/TONIGHT...THE MID-UPPER LEVEL PICTURE
FEATURES THE AFOREMENTIONED/RATHER SUBTLE LEAD SHORTWAVE
DISTURBANCE CROSSING OVER THE LOCAL AREA...WHILE MORE ENERGETIC
WAVES REMAIN WELL OFF TO THE WEST-SOUTHWEST. MEANWHILE AT THE
SURFACE...THE RIDGE AXIS WILL SLOWLY EDGE EASTWARD. ALTHOUGH WIND
SPEEDS SHOULD REMAIN LIGHT GENERALLY WELL-UNDER 10 MPH THROUGH THE
ENTIRE NIGHT...DIRECTION WILL GRADUALLY TRANSITION FROM NORTHERLY
TO EASTERLY. DESPITE THE FAIRLY WEAK NATURE OF THE PASSING
DISTURBANCE...MODEL RELATIVE HUMIDITY PROGS DEPICT A FAIRLY DECENT
COVERAGE OF MID-HIGH CLOUD COVER THROUGH THE NIGHT...AND HAVE THE
ENTIRE CWA IN PARTLY TO MOSTLY CLOUDY SKY COVER CATEGORY. WHILE
CONFIDENCE IS FAIRLY HIGH IN A PRECIP-FREE NIGHT (ESPECIALLY
MEASURABLE) AND THE OFFICIAL FORECAST REFLECTS SUCH...WOULD NOT BE
TOTALLY SURPRISED TO SEE A WEST-EAST ORIENTED BAND OF FLURRIES
TRY TO GET GOING LATE IN THE NIGHT MAINLY OVER/NEAR THE NORTHERN
CWA IN RESPONSE TO SOME FAIRLY MODEST ISENTROPIC LIFT/FRONTOGENESIS
FOCUSED IN THE ENTRANCE REGION OF A DEPARTING UPPER JET STREAK.
DESPITE THE LIGHT BREEZES...THE EXPECTED FAIRLY HIGH SKY COVER
SHOULD KEEP TEMPS FROM REALLY FALLING OFF...AND AS A RESULT KEPT
LOW TEMPS GENERALLY 2-4 DEGREES ABOVE A 00Z MET/MAV GUIDANCE
BLEND...AIMING MOST OF THE CWA INTO THE 15-20 RANGE...EXCEPT FOR
COLDER READINGS AROUND 10 FAR NORTH. LASTLY...DESPITE FAIRLY HIGH
VALUES OF FORECAST LOW-LEVEL RELATIVE HUMIDITY...CONFIDENCE WAS
NOT SUFFICIENT ENOUGH IN FOG FORMATION TO INTRODUCE EVEN A PATCHY
MENTION FOR LATE TONIGHT...ALTHOUGH 03Z SREF/06Z NAM VISIBILITY
PROGS SUGGEST THAT MAYBE LOCALIZED POCKETS OF MAINLY THE FAR
WESTERN CWA COULD BEAR WATCHING FOR THIS...ESPECIALLY IF ENOUGH
SNOW MANAGES TO MELT TODAY TO ENHANCE LOW-LEVEL MOISTURE.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 334 AM CST TUE DEC 16 2014
THE LONG TERM DISCUSSION WILL BE ADDED HERE WITHIN THE NEXT HOUR
OR SO...STAY TUNED.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1208 AM CST TUE DEC 16 2014
ALTHOUGH CONFIDENCE IS RATHER HIGH IN BOTH WIND SPEEDS/DIRECTION
AND THE FACT THAT VFR VISIBILITY SHOULD PREVAIL...UNFORTUNATELY
THERE ARE SOME QUESTION MARKS REGARDING CEILING TRENDS...INVOLVING
BOTH WHEN A RETURN TO VFR MIGHT OCCUR AND IF SO FOR HOW LONG. IN
SHORT...OPTED TO ERR A BIT MORE ON THE CAUTIOUS/PESSIMISTIC SIDE
VERSUS PREVIOUS TAF ISSUANCE AND EXTEND AN MVFR CEILING THROUGH
18Z...WITH SOME MODELS/GUIDANCE SUGGESTING THIS MAY BE TOO
LONG...WHILE OTHERS SUGGEST IT MAY NOT BE LONG ENOUGH WITH THE
POTENTIAL FOR MVFR THROUGHOUT THE ENTIRE PERIOD. SO FOR NOW AM
JUST PLAYING A MIDDLE-GROUND. NO MATTER WHAT CEILINGS
DO...CONFIDENCE IS HIGH IN A PRECIPITATION-FREE PERIOD. WIND-
WISE...THINGS START OUT QUITE BRISK EARLY THIS MORNING WITH
SEVERAL MORE HOURS OF NORTHWESTERLY GUST POTENTIAL TO AROUND 30KT
POSSIBLE...ALTHOUGH A SLOW-BUT-STEADY DECREASING TREND WILL TAKE
PLACE DURING THE PERIOD WITH GUST POTENTIAL BY MID-DAY EASING
BELOW 20KT...AND IN FACT FAIRLY LIGHT BREEZES IN PLACE BY TUESDAY
EVENING AS HIGH PRESSURE SETTLES IN.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1125 PM CST MON DEC 15 2014
.SYNOPSIS...
ISSUED AT 315 PM CST MON DEC 15 2014
H5 ANALYSIS FROM EARLIER THIS MORNING HAD AN UPPER LEVEL
LOW OVER CENTRAL KS IN THE VICINITY OF SALINA WITH A TROUGH
EXTENDING SWD INTO THE ARKLATEX. DOWNSTREAM RIDGING WAS PRESENT
ACROSS THE EASTERN GREAT LAKES AND MID ATLANTIC STATES. NORTHWEST OF
THE CLOSED LOW...HIGH PRESSURE WAS PRESENT OVER NWRN ALBERTA...WHILE
A TROUGH OF LOW PRESSURE EXTENDED FROM THE GULF OF ALASKA SOUTH TO
JUST OFF THE COAST OF NRN CALIFORNIA. AS OF 2 PM CST...THE UPPER
LEVEL LOW HAD TRACKED FROM CENTRAL KS TO JUST NORTH OF CHILLICOTHE
MO. AT THE SURFACE...LOW PRESSURE WAS IN THE VICINITY OF LAMONI IOWA
WITH A COLD FRONT EXTENDING SSE INTO SOUTH CENTRAL MO. HIGH PRESSURE
WAS NOTED OVER EASTERN MT. ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA...STRONG NORTHERLY WINDS WERE PRESENT...ALONG WITH LIGHT
SNOW...WHICH AS REDUCED VISIBILITIES DOWN TO 1/2SM TO 2SM AS OF 2 PM
CST. UNDER CLOUDY SKIES...TEMPERATURES AS OF 2 PM CST RANGED
FROM...25 AT VALENTINE...TO 29 AT NORTH PLATTE...BROKEN BOW AND
OGALLALA.
&&
.UPDATE...
ISSUED AT 903 PM CST MON DEC 15 2014
RADAR IS QUIET BUT THERE IS LIGHT SNOW AT KONL WITH VISIBILITY
2 TO 3 MILES AND WIND SPEEDS NEVER CAME UP IN THIS AREA SO IT IS
NOT BLOWING SNOW. GIVEN THE RADAR TRENDS AT KLNX AND KFSD...THIS
SNOW SHOULD BE ENDING BY 11 PM SO THE WINTER WEATHER HIGHLIGHTS
HAVE BEEN ALLOWED TO EXPIRE AT 9 PM CST.
UPDATE ISSUED AT 612 PM CST MON DEC 15 2014
SOME WEATHER HIGHLIGHTS HAVE BEEN ALLOWED EXPIRE AT 6 PM. JUST
FLURRIES ARE INDICATED ALONG HIGHWAY 61 AND INTERSTATE 80. CLOUD
CEILINGS ARE RISING IN THIS AREA SUPPORTING LIGHTER WINDS.
THE HRRR...RAP AND NAM SHOW FOG ACROSS WRN NEB BY MORNING AS THE
MONTANA SFC HIGH PRESSURE SYSTEM BUILDS ACROSS THIS AREA BY 12Z
TUESDAY. ALSO...LOWERED OVERNIGHT TEMPERATURES IN THIS AREA.
THESE MODELS SHOW WINDS OF 5 KT OR LESS WITH CLEARING SKIES AND
RADIATIVE COOLING TAKING HOLD. SOME DRY AIR WILL BE MOVING IN
ALOFT SUPPORTING LOWS NEAR ZERO BUT NOT SO DRY AS TO SUPPORT
WIDESPREAD SUBZERO LOWS. FOG WILL LIKELY FORM BEFORE THIS HAPPENS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 315 PM CST MON DEC 15 2014
FOR THE NEXT 36 HOURS...MAIN FORECAST CONCERNS REVOLVE
AROUND THE EXIT OF THE UPPER LEVEL SYSTEM THAT IS BRINGING
WIDESPREAD ACCUMULATING SNOW TO THE REGION. TEMPERATURE FORECAST
TONIGHT AND TOMORROW ALSO DESERVES CONSIDERATION.
FORECAST GUIDANCE INDICATES THE UPPER LOW WILL CONTINUE TO THE EAST
OVER THE UPPER MISSISSIPPI VALLEY...AND GET CAUGHT UP IN A NORTHERN
STREAM SHORTWAVE/UPPER LOW OVER THE NEXT 24 HOURS. LOW AMPLITUDE
TRANSITORY RIDGING WILL THEN TAKE HOLD ACROSS THE CENTRAL PLAINS AS
THE NEXT UPPER LEVEL TROUGH DEEPENS OVER THE WESTERN COAST. AT THE
SURFACE...CANADIAN HIGH PRESSURE WILL FILL SOUTH BEHIND THE
DEPARTING SURFACE LOW PROVIDING FOR DRIER CONDITIONS AND COOLER
TEMPERATURES. WITH CAA FILTERING SOUTH ACROSS THE
PLAINS...OVERNIGHT LOWS WILL BE CHILLY...GENERALLY IN THE SINGLE
DIGITS AND LOWER TEENS FROM WEST TO EAST ACROSS THE FORECAST AREA.
THE OVERNIGHT TEMPERATURE FORECAST IS A PRODUCT OF NUMERICAL
GUIDANCE WITH THE PREVIOUS FORECAST...WHICH ASSUMES SOME CLEARING.
IF SUBSTANTIAL CLEARING WERE TO OCCUR...TEMPERATURES MAY PLUMMET
ACROSS OUR WESTERN ZONES AS A FRESH SNOWPACK COMBINES WITH LIGHT
WINDS. HIGHS REBOUND SOME TUESDAY...BUT WITH CANADIAN HIGH PRESSURE
OVERHEAD...AND WEAK COLD AIR ADVECTION CONTINUING...HIGHS SHOULD
ONLY TOP OUT IN THE 20S FOR LOCATIONS ALONG AND NORTH OF
I80...POSSIBLY A FEW LOWER 30S COULD BE ACHIEVED ACROSS OUR SOUTH AS
THE WINDS BEGIN TO VEER TO THE SOUTH LATE IN THE DAY BEHIND THE HIGH.
CONCERNING PRECIPITATION...NEAR TERM GUIDANCE HAS ACCUMULATING
SNOWFALL OUT OF THE CWA...SAVE FOR THE NORTHEASTERN SANDHILLS AND
NORTH CENTRAL NEBRASKA BY 00Z THIS EVENING...WITH SNOW ENDING
GENERALLY AT 03Z FOR OUR FAR NORTHEAST. THE FORECAST USED A BLEND
OF THE 15.12Z NAM12 WITH THE LATEST RAP WHICH SEEMS TO PROVIDE A
PLAUSIBLE NORTHWEST TO EAST DEMISE OF THE SNOWFALL. IR
SATELLITE/RADAR TRENDS OVER THE PAST FEW HOURS EARLY AFTERNOON
SUPPORT THE IDEA AS CLOUD TOPS ARE WARMING AND REFLECTIVITY IS
BECOMING LESS DEFINED. SUPPOSE ANOTHER INCH OR TWO OF SNOW IS STILL
POSSIBLE ACROSS OUR NORTHERN ZONES LATE THIS AFTERNOON AS THE MODELS
SUGGEST QPF RATES OF UP TO FIVE HUNDREDTHS OF AN INCH PER HOUR
CONTINUING UNTIL 03Z. IMPACTS FROM ANY ADDITIONAL SNOW HOWEVER WILL
CONTINUE TO COMPOUND VISIBILITY ISSUES WITH BLOWING SNOW FROM THE
30-40 MPH GUSTS OCCURRING...WINDS WILL WEAKEN THOUGH AS THE PRESSURE
GRADIENT RELAXES THIS EVENING.
THE CURRENT WINTER STORM WARNING AND WINTER WEATHER ADVISORY WILL
EXPIRE AT 00Z THIS EVENING...BUT A FEW SMALL CHANGES MAYBE/ARE
NEEDED. ACROSS NORTH CENTRAL NEBRASKA...A EXTENSION OF THE
ADVISORY/WARNING IS NEEDED THROUGH 03Z TO ACCOUNT FOR THE LATER
ENDING TIME OF SNOW AND GUSTY NORTHWEST WIND. COUNTIES MAY BE
DROPPED ACROSS OUR FAR SOUTH EARLY..BUT THE RECENT OB FROM KMCK
SUGGEST LIGHT TO OCCASIONAL MODERATE SNOW...WILL RE-EVALUATE IN THE
NEXT COUPLE HORUS. ELSEWHERE THE HEADLINES ARE ANTICIPATED TO BE
ALLOWED TO EXPIRE ON TIME.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 315 PM CST MON DEC 15 2014
MID RANGE...TUESDAY NIGHT THROUGH THURSDAY...IN THE MID
RANGE PERIODS...TEMPERATURES AND PRECIPITATION CHANCES ON WEDNESDAY
NIGHT ARE THE MAIN FORECASTING CHALLENGES IN THE MID RANGE PERIODS.
FOR TUESDAY NIGHT...A TROUGH OF LOW PRESSURE ALOFT WILL PUSH INTO
SRN CALIFORNIA RESULTING IN ANOTHER SOAKER FOR THE SWRN CONUS.
DOWNSTREAM OF THE TROUGH...LOW AMPLITUDE RIDGING WILL EXTEND ACROSS
THE SRN PLAINS INTO NEBRASKA. SURFACE HIGH PRESSURE WILL DOMINATE
THE PLAINS STATES AND OZARKS TUESDAY NIGHT. WITH FRESH
SNOWCOVER...LIGHT WINDS AND PARTLY CLOUDY SKIES...LOWS WILL BE COLD
IN THE SINGLE DIGITS AND LOWS WERE TRENDED DOWNWARD FROM THE
INHERITED FORECAST. FOR WEDNESDAY AND WEDNESDAY NIGHT...THE UPPER
LEVEL TROUGH WILL MIGRATE EAST INTO THE DESERT SOUTHWEST. SOME MODEL
DIFFERENCES WERE NOTED WITH THE FORWARD SPEED AND TRACK OF THIS
SYSTEM MIDWEEK. THE LATEST NAM AND ECMWF SOLNS FROM 12Z THIS MORNING
ACTUALLY DEVELOP A CLOSED LOW ALONG THE AZ/NM AND MEXICAN BORDER AT
00Z FRIDAY. THE GFS IS FASTER AND OPEN WITH THIS SYSTEM...MIGRATING
IT INTO NM AND WEST TX BY 00Z FRIDAY. WHAT ALL THREE MODELS DO
INDICATE IS A LEAD DISTURBANCE WHICH CROSSES THE SRN PLAINS INTO THE
OZARKS WEDNESDAY NIGHT. BOTH THE GFS AND ECMWF SOLNS LIFT INCREASED
LOW LEVEL MOISTURE INTO SRN NEBRASKA WEDNESDAY NIGHT IN ASSOCIATION
WITH THE LEAD DISTURBANCE. LIFT HOWEVER REMAINS WEAK PER CROSS
SECTIONS...AND WITH A FAIRLY DRY LAYER AROUND H7...AM NOT TOO
EXCITED ABOUT PCPN IN OUR AREA WEDS NIGHT. INHERITED FCST HAD A
SLIGHT CHANCE MENTION IN THE SOUTH AND SERN CWA DURING THE PERIOD
AND GIVEN THE LOW LEVEL MOISTURE AND SOME MODEL AGREEMENT BETWEEN
THE GFS AND ECMWF SOLNS...WILL LEAVE POP MENTION UNCHANGED FOR NOW.
AS FOR PTYPE WEDNESDAY NIGHT...LOOKING AT FCST SOUNDINGS...WAS
INITIALLY A LITTLE CONCERNED ABOUT THE THREAT FOR FREEZING DRIZZLE
IN THE SERN CWA. LOOKING AT BUFKIT SOUNDINGS...THE THREAT FOR FZDZ
SHOULD BE OFF TO THE SOUTHEAST OF THE FORECAST AREA AND WILL LEAVE
PRECIP MENTION AS ALL SNOW.
THURSDAY NIGHT THROUGH MONDAY...A TANDEM OF SRN STREAM WAVES WILL
TRACK ACROSS THE SRN TIER OF STATES FRIDAY...AND THEN AGAIN SUNDAY
NIGHT INTO MONDAY. ATTM...FAVORABLE FORCING FOR PRECIPITATION SHOULD
REMAIN SOUTH OF THE FORECAST AREA SO WILL FORECAST DRY CONDS ATTM.
HOWEVER...THE LATEST GFS SOLN BEGINS TO DIVERGE TOWARD A MORE ACTIVE
NRN STREAM NEXT WEEK...FORCING A CLIPPER SYSTEM THROUGH THE NRN
PLAINS EARLY NEXT WEEK...FOLLOWED BY SECOND...MUCH STRONGER NRN
STREAM SYSTEM AROUND CHRISTMAS EVE. IF THIS WOULD VERIFY...WE COULD
SEE COLD TEMPERATURES AND A POSSIBLE THREAT FOR SNOW. IN THE
MEANTIME...DECIDED TO KEEP CONDS DRY THROUGH THE WEEKEND AND INTO
NEXT WEEK...GIVEN THE ACTIVE SRN STREAM...WITH PCPN EXPECTED WELL
SOUTH OF THE FCST AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1125 PM CST MON DEC 15 2014
WIDESPREAD MVFR CIGS EXTEND THROUGH THE FCST NORTH INTO THE NRN
PLAINS AND SOME MODELS HOLD THEM IN PLACE OVERNIGHT THROUGH
TUESDAY WHILE OTHERS MIX OUT TO VFR ALMOST IMMEDIATELY. SINCE THE
MODELS ARE FAIRLY EVENLY SPLIT...NO CONSENSUS...THE FCST RELIES ON
DAYTIME MIXING WITH VFR EXPECTED 15Z-18Z TUESDAY. VFR IS EXPECTED
THEREAFTER.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CDC
SYNOPSIS...CLB
SHORT TERM...JACOBS
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1036 PM MST MON DEC 15 2014
.AVIATION...
06Z TAF CYCLE
A RIDGE OF HIGH PRESSURE WILL CROSS ALOFT FOR THE REST OF TONIGHT.
THE CEILING WILL GRADUALLY LOWER AS AN UPPER LEVEL TROUGH
APPROACHES FROM THE WEST TUESDAY AND TUESDAY NIGHT. WINTRY
PRECIPITATION SHOULD DEVELOP ALONG AND WEST OF THE CONTDVD LATE
TUESDAY NIGHT WITH FLIGHT CATEGORY RESTRICTIONS AND MT
OBSCURATIONS.
44
&&
.PREV DISCUSSION...346 PM MST MON DEC 15 2014...
.SYNOPSIS...
HIGH CLOUDS WILL ONCE AGAIN STREAM IN FROM THE WEST THIS EVENING
THROUGH THE DAY TUESDAY. ANOTHER PACIFIC STORM SYSTEM AND THE
ASSOCIATED MOISTURE OUT AHEAD OF IT WILL BRING A FEW LIGHT SHOWERS
TO THE NORTHWEST THIRD OF THE STATE TUESDAY NIGHT. AS THE MAIN
STORM SYSTEM MOVES INTO ARIZONA WEDNESDAY EVENING...SCATTERED SHOWERS
AND SNOW SHOWERS ABOVE ABOUT 6000 FEET WILL SPREAD INTO WESTERN NEW
MEXICO. THE SHOWERS WILL SPREAD INTO CENTRAL NEW MEXICO THURSDAY.
SIGNIFICANT SNOW IS POSSIBLE OVER ALL MOUNTAIN AREAS. HIGH PRESSURE
RETURNS FOR FRIDAY AND SATURDAY WITH THE NEXT STORM SYSTEM
EXPECTED SUNDAY AND MONDAY.
&&
.DISCUSSION...
RIBBON OF STRONG NORTHWEST WINDS CONTINUE FROM THE SANDIA AND MANZANO
MOUNTAINS EAST TO CLINES CORNERS. RUC AND NAM BOTH INDICATING THESE
STRONG NW WINDS WILL DIMINISH RAPIDLY AROUND SUNSET. LEFT OUT MENTION
OF OVERNIGHT FOG OUTSIDE THE MORENO VALLEY GIVEN THAT NAMBUFR DATA
SUGGESTING THAT SCATTERED TO BROKEN MID CLOUDS WILL SPREAD FROM
SOUTHWEST TO NORTHEAST ACROSS WESTERN AND CENTRAL NEW MEXICO
TONIGHT...LIMITING RADIATIONAL COOLING. WEAK BACKDOOR COLD FRONT
EXPECTED TO SLIDE SWD INTO NE NM THIS EVENING. LOWERED OVERNIGHT
LOW TEMPERATURES A FEW DEGREES BELOW GUIDANCE FOR THE NE PLAINS AS
A RESULT. A BRIEF SPURT OF LIGHT EAST WINDS IS POSSIBLE INTO THE
MIDDLE RIO GRANDE VALLEY TUESDAY MORNING.
NAM AND GFS IN GOOD AGREEMENT THAT THE OVERHEAD RIDGE AXIS WILL SHIFT
EAST OF NM LATE TONIGHT/TUESDAY MORNING. INCREASING SOUTHWEST FLOW
ALOFT WILL RESULT IN SLIGHT WARMING FOR TUESDAY BUT PLENTIFUL HIGH
CLOUDS WILL KEEP THE WARMING IN CHECK.
MODELS IN FAIRLY GOOD AGREEMENT REGARDING THE NEXT UPPER LEVEL
TROUGH/CLOSED LOW FOR WEDNESDAY AND THURSDAY. SUB-TROPICAL JET
STREAM SPEED MAXIMA MOVE UP FROM THE SOUTHWEST TUESDAY NIGHT AND
WEDNESDAY MORNING...BRINGING CHANCES FOR SHOWERS AND SNOW SHOWERS
ABOVE ABOUT 6500FT OVER THE NORTHWEST THIRD OR SO OF THE STATE.
GFS AND NAM STILL AT ODDS WITH ONE ANOTHER AS TO WHEN TO BRING
THE MAIN TROUGH./CLOSED LOW THROUGH THE STATE AND WHEN BEST
CHANCES FOR PRECIP WILL BE WEDNESDAY OR THURSDAY. SIGNIFICANT SNOW
IS POSSIBLE OVER ALL MOUNTAIN AREAS WEDNESDAY NIGHT OR THURSDAY
GIVEN THE PWAT AMOUNT AVAILABLE. FUTURE MODEL RUNS SHOULD COME TO BETTER
AGREEMENT WITH REGARD TO TIMING BUT FOR NOW HAVE ADVISORY SNOW
AMOUNTS ABOVE ABOUT 7000FT WEDNESDAY NIGHT AND THURSDAY IN THE
GRIDS.
GFS STARTED WITH 06Z RUN LAST NIGHT BUT NOW ALL GLOBAL MODELS
TRENDING AWAY FROM A SLOW MOVING CLOSED LOW FOR THE WEEKEND. BOTH GFS
AND ECMWF TRENDING TOWARD A MUCH MORE PROGRESSIVE TROUGH. SLIGHT
VARIATIONS IN THE EXCEPTIONALLY FAST (185-190KT) PACIFIC JET
STREAM OVER THE CENTRAL PACIFIC ARE LEADING TO LARGE RUN TO RUN
MODEL DIFFERENCES. LOW CONFIDENCE IN THE FORECAST BEYOND FRIDAY
CONTINUES WITH SUCH BIG RUN TO RUN SWINGS. OVERALL PATTERN REMAINS
ACTIVE BUT STRENGTH OF SYSTEMS REMAINS IN QUESTION AT THIS TIME.
33
&&
.FIRE WEATHER...
POOR VENTILATION TODAY...BUT SOME IMPROVEMENT FORECAST TUESDAY INTO
WEDNESDAY AS AN UPPER LEVEL RIDGE AXIS SHIFTS EAST OF THE AREA AND
WINDS THROUGHOUT THE COLUMN RESPOND TO A TROUGH PROGRESSING EASTWARD
INTO THE DESERT SW AND GREAT BASIN. ALTHOUGH VENT RATES WILL TREND
UP TO FAIR/GOOD MOST AREAS BY WEDNESDAY...POCKETS OF POOR WILL STILL
REMAIN IN SOME VALLEYS.
ANOTHER WETTING EVENT LOOKS ON TRACK FOR WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT...ESPECIALLY ACROSS WESTERN AND NORTH CENTRAL
PORTIONS OF THE AREA. THE 12Z MODEL SOLUTIONS ARE SHOWING A MESSY
TROUGH PASSAGE SCENARIO WITH SEVERAL SHORTWAVE TROUGHS IMPACTING THE
PASSAGE OF AN UPPER LEVEL LOW...WHICH IS DIFFERENT FROM YESTERDAY`S
12Z RUNS. THE 18Z NAM SHOWS A WETTER SCENARIO WITH A MORE COHERENT
UPPER LEVEL LOW MOVING EAST ACROSS THE FORECAST AREA THURSDAY NIGHT.
POTENTIAL FOR A WIDESPREAD WETTING EVENT IS THERE...BUT FORECASTER
CONFIDENCE IS ONLY MODERATE AT THIS POINT GIVEN THE MODEL RUN-TO-RUN
INCONSISTENCY. VENT RATES WILL TAKE A HIT BEHIND THE DEPARTING
TROUGH THROUGH SATURDAY BEFORE IMPROVING AGAIN.
FORECAST UNCERTAINTY FOR A LATE WEEKEND AND EARLY NEXT WEEK WETTING
EVENT HAS INCREASED GIVEN THE 12Z MEDIUM RANGE MODEL SOLUTIONS...
WHICH LOOK MUCH DIFFERENT THAN THE 00Z RUNS...ESPECIALLY THE GFS
WHICH IS NOW SHOWING A PROGRESSIVE OPEN WAVE. REGARDLESS...MODERATE
TO HIGH FORECASTER CONFIDENCE ON THE UNSETTLED AND POTENTIALLY WET
PATTERN PERSISTING THROUGH EARLY NEXT WEEK.
11
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
743 PM EST WED DEC 17 2014
.SYNOPSIS...
AN UPPER LEVEL STORM SYSTEM MOVING FROM THE GREAT LAKES TO NEW
ENGLAND WILL RESULT IN SCATTERED SNOW SHOWERS CONTINUING INTO
THURSDAY. FARTHER SOUTH A FEW SPRINKLES AND FLURRIES CAN BE
EXPECTED IN NORTHEAST PENNSYLVANIA. CLOUDS AND SEASONABLY COLD
TEMPERATURES WILL PERSIST FRIDAY INTO THE WEEKEND WITH SCATTERED
SNOW SHOWERS GRADUALLY DIMINISHING.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
740 PM UPDATE...
AREA OF PCPN HAS WEAKENED ACRS CWA THIS EVNG. UPR LVL S/WV IS NOW
ROTATING INTO WRN NY AND BRINGING STEEPENING MID-LVL LR TO THE
REGION. THIS ADDED LIFT COMBINED WITH LK MOISTURE WL SERVE TO
INCRS CVRG OF SNOW SHOWERS FOR PORTION OF OVRNGT IN 290-300 FLOW
ON EITHER SIDE OF MIDNIGHT.
EXPECT THAT OVRNGT SNOW ACCUMS ARND 1.5 INCHES IN FAVORED
LOCATIONS WITH HIGHEST AMNTS IN THE HIGHER TERRAIN OF UPR
SUSQUEHANNA REGION. ONLY MINOR CHGS MADE TO POPS WITH NO OTHER
CHGS NEEDED AT THIS TIME. EXPECT THAT NEPA WL STAY CLDY BUT VRY
LITTLE PCPN EXPECTED TO SNEAK INTO ZONES TONIGHT.
PREV DISCUSSION BLO...
A BAND OF STEADY LIGHT RAIN IS MOVING EAST ACROSS CENTRAL NY THIS
AFTERNOON WITH A CHANGE-OVER TO LIGHT SNOW ALREADY OCCURRING OVER
THE HIGHER ELEVATIONS AS OF 3 PM. THIS BAND WILL LIFT EAST-
NORTHEAST TOWARD THE CATSKILLS AND MOHAWK VALLEY THROUGH LATE THIS
AFTERNOON WITH LOWER ELEVATIONS GRADUALLY MIXING WITH OR CHANGING
TO LIGHT SNOW AS COLDER AIR FILTERS IN FROM THE WEST. MEANWHILE...
MAINLY DRY WEATHER CAN BE EXPECTED TO CONTINUE IN THE WILKES-BARRE
AND SCRANTON AREAS AND POINTS SOUTH WITH PRECIPITATION REMAINING
TO THE NORTH.
PRECIPITATION SHOULD BECOME SPOTTIER AND LIGHTER EARLY THIS
EVENING IN MANY AREAS... THEN UPPER LEVEL LOW PRESSURE CURRENTLY
OVER WESTERN MICHIGAN WILL TRACK RAPIDLY EAST ACROSS THE AREA
LATER TONIGHT. THIS COULD RESULT IN A PERIOD OF ENHANCED SNOW
SHOWERS AGAIN LATE TONIGHT INTO EARLY THURSDAY MORNING. A BIT OF
LAKE ENHANCEMENT COULD ALSO OCCUR SOUTHEAST OF LAKE ONTARIO LATE
TONIGHT AS 850 MB TEMPERATURES FALL TO AROUND -8 C. LATEST HIGH
RESOLUTION NAM AND HRRR BOTH SUPPORT THE IDEA THAT SNOW SHOWERS
MAY INCREASE IN COVERAGE LATE TONIGHT WITH THE PASSAGE OF THIS
SYSTEM. BASED ON THIS HAVE UPPED POPS INTO THE LIKELY CATEGORY
LATER TONIGHT AND HAVE UP TO AN INCH OF SNOW POSSIBLE ESPECIALLY
AT HIGHER ELEVATIONS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
UPPER LEVEL AND SURFACE LOW PRESSURE WILL TRACK SLOWLY EAST ACROSS
THE SOUTHERN CANADIAN MARITIMES THURSDAY THROUGH FRIDAY. FLOW
ACROSS OUR AREA IN THE WAKE OF THIS SYSTEM WILL BE NORTHWESTERLY WITH
PLENTY OF LOW-LEVEL MOISTURE AND 850 MB TEMPERATURES HOLDING
AROUND -8 TO -10 C... WHICH WILL BE JUST COLD ENOUGH FOR A MINOR
LAKE RESPONSE IN THE NORTHWEST FLOW. HOWEVER MOISTURE WILL BECOME
INCREASINGLY SHALLOW WITH CONSIDERABLE DRYING IN THE -10 TO -20
DEGREE SNOW GROWTH ZONE BY THURSDAY AFTERNOON. BASED ON THIS
EXPECT JUST SCATTERED LIGHT SNOW SHOWERS THURSDAY AFTERNOON INTO
FRIDAY WITH ONLY MINIMAL ACCUMULATIONS. SOME FREEZING DRIZZLE
MIGHT EVEN OCCUR THURSDAY NIGHT ALTHOUGH AT THIS POINT I THINK
THAT IS A LOW PROBABILITY SCENARIO AND I HAVE NOT INCLUDED ZL IN
THE GRIDDED FORECAST. AT THIS POINT IT APPEARS THAT CLOUDS WILL
PERSIST THROUGH FRIDAY. WITH PLENTY OF CLOUDS WE ARE NOT EXPECTING
MUCH DIURNAL VARIATION IN TEMPERATURES THROUGH FRIDAY WITH HIGHS
MAINLY 30 TO 35 AND LOWS 20 TO 25 IN MOST PLACES.
BEST CHANCE TO SEE ANY SUNSHINE MIGHT BE EARLY SATURDAY BEFORE
CLOUDS AHEAD OF THE NEXT SYSTEM STREAM NORTHEAST ACROSS THE AREA
DURING THE AFTERNOON. SATURDAY SHOULD BE DRY WITH TEMPERATURES
AGAIN MAINLY IN THE 30S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
1 PM UPDATE..
FOLLOWED WPC GUIDANCE FOR THE MOST PART. SAT NGT AND SUN SOME
LIGHT SNOW WITH AN INVERTED TROF FROM A COASTAL STORM WELL OUT TO
SEA. SNOW ACCUMULATIONS WILL BE MOSTLY 2 INCHES OR LESS.
DRY SUN NGT AND MON WITH A MILD SFC HIGH. MON NGT AND TUE MODELS
NOW TRYING TO BRING A WEAK COASTAL STORM NE INTO THE AREA WITH
MIXED PRECIP. ADDED SOME LOW CHC POPS.
WED A STRONG OCCLUDED FRONT LIFTS NE AHEAD OF A LARGE BOMBING
STACKED LOW IN THE MIDWEST. WARM AIR SO PRECIP MOSTLY RAIN. THIS
WILL NEED TO BE WATCHED FIRST FOR RAIN AMOUNTS AND POSSIBLY
FLOODING AND SECOND FOR STRONG GUSTY WINDS.
ON THE TAIL END OF THE STEADY RAIN IT WILL CHANGE OVER TO SNOW WED
NGT AND STAY COLD THE REST OF THE WEEK WITH WRAP AROUND SNOW.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
MVFR CONDITIONS WILL GENERALLY BE THE RULE THROUGH THURSDAY
AFTERNOON AS LOW LEVEL MOISTURE AND SNOW SHOWERS / FLURRIES
CONTINUE TO AFFECT THE AREA IN ASSOCIATION WITH AN UPPER LEVEL LOW
AND SOME LAKE EFFECT.
AS FAR AS SPECIFICS, WE EXPECT FLURRIES AND SNOW SHOWERS TO BE
MOST PERSISTENT FOR KSYR AND KRME. KRME SHOULD SEE MAINLY IFR
CEILINGS AND MVFR VISBYS IN FLURRIES THROUGH THIS EVENING WITH
CEILINGS IMPROVING TO MVFR LATER TONIGHT INTO TOMORROW. KSYR
SHOULD BE MAINLY MVFR BUT COULD GO IFR VISBYS AT TIMES LATER TONIGHT
INTO TOMORROW IF HEAVIER SNOW SHOWERS AFFECT THE AREA.
FURTHER SOUTH, STEADIER PRECIP SHOULD CONTINUE TO DIMINISH THIS
EVENING AND WE EXPECT MAINLY MVFR CEILINGS AND VFR VISBYS THROUGH
THE TAF PERIOD FOR KELM, KITH, AND KBGM WHILE KAVP REMAINS VFR.
OUTLOOK...
THUR NIGHT TO FRI... MAINLY VFR. MVFR/IFR RESTRICTIONS ARE PSBL AT
KRME/KSYR/KITH/KBGM DUE TO CIGS AND AT TIMES WITH -SHSN.
FRI NGT TO SAT...VFR.
SAT NGT AND SUN...MVFR/IFR IN LIGHT SNOW.
SUN NGT AND MON...VFR/MVFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE/PVF
SHORT TERM...MSE
LONG TERM...TAC
AVIATION...PCF/TAC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
638 PM EST WED DEC 17 2014
.SYNOPSIS...
AN UPPER LEVEL STORM SYSTEM MOVING FROM THE GREAT LAKES TO NEW
ENGLAND WILL RESULT IN RAIN SHOWERS CHANGING TO SNOW SHOWERS
ACROSS NEW YORK STATE LATE TODAY WITH SCATTERED SNOW SHOWERS
CONTINUING TONIGHT INTO THURSDAY. FARTHER SOUTH A FEW SPRINKLES
AND FLURRIES CAN BE EXPECTED IN NORTHEAST PENNSYLVANIA. CLOUDS AND
SEASONABLY COLD TEMPERATURES WILL PERSIST FRIDAY INTO THE WEEKEND
WITH SCATTERED SNOW SHOWERS GRADUALLY DIMINISHING.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
A BAND OF STEADY LIGHT RAIN IS MOVING EAST ACROSS CENTRAL NY THIS
AFTERNOON WITH A CHANGE-OVER TO LIGHT SNOW ALREADY OCCURRING OVER
THE HIGHER ELEVATIONS AS OF 3 PM. THIS BAND WILL LIFT EAST-
NORTHEAST TOWARD THE CATSKILLS AND MOHAWK VALLEY THROUGH LATE THIS
AFTERNOON WITH LOWER ELEVATIONS GRADUALLY MIXING WITH OR CHANGING
TO LIGHT SNOW AS COLDER AIR FILTERS IN FROM THE WEST. MEANWHILE...
MAINLY DRY WEATHER CAN BE EXPECTED TO CONTINUE IN THE WILKES-BARRE
AND SCRANTON AREAS AND POINTS SOUTH WITH PRECIPITATION REMAINING
TO THE NORTH.
PRECIPITATION SHOULD BECOME SPOTTIER AND LIGHTER EARLY THIS
EVENING IN MANY AREAS... THEN UPPER LEVEL LOW PRESSURE CURRENTLY
OVER WESTERN MICHIGAN WILL TRACK RAPIDLY EAST ACROSS THE AREA
LATER TONIGHT. THIS COULD RESULT IN A PERIOD OF ENHANCED SNOW
SHOWERS AGAIN LATE TONIGHT INTO EARLY THURSDAY MORNING. A BIT OF
LAKE ENHANCEMENT COULD ALSO OCCUR SOUTHEAST OF LAKE ONTARIO LATE
TONIGHT AS 850 MB TEMPERATURES FALL TO AROUND -8 C. LATEST HIGH
RESOLUTION NAM AND HRRR BOTH SUPPORT THE IDEA THAT SNOW SHOWERS
MAY INCREASE IN COVERAGE LATE TONIGHT WITH THE PASSAGE OF THIS
SYSTEM. BASED ON THIS HAVE UPPED POPS INTO THE LIKELY CATEGORY
LATER TONIGHT AND HAVE UP TO AN INCH OF SNOW POSSIBLE ESPECIALLY
AT HIGHER ELEVATIONS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
UPPER LEVEL AND SURFACE LOW PRESSURE WILL TRACK SLOWLY EAST ACROSS
THE SOUTHERN CANADIAN MARITIMES THURSDAY THROUGH FRIDAY. FLOW
ACROSS OUR AREA IN THE WAKE OF THIS SYSTEM WILL BE NORTHWESTERLY WITH
PLENTY OF LOW-LEVEL MOISTURE AND 850 MB TEMPERATURES HOLDING
AROUND -8 TO -10 C... WHICH WILL BE JUST COLD ENOUGH FOR A MINOR
LAKE RESPONSE IN THE NORTHWEST FLOW. HOWEVER MOISTURE WILL BECOME
INCREASINGLY SHALLOW WITH CONSIDERABLE DRYING IN THE -10 TO -20
DEGREE SNOW GROWTH ZONE BY THURSDAY AFTERNOON. BASED ON THIS
EXPECT JUST SCATTERED LIGHT SNOW SHOWERS THURSDAY AFTERNOON INTO
FRIDAY WITH ONLY MINIMAL ACCUMULATIONS. SOME FREEZING DRIZZLE
MIGHT EVEN OCCUR THURSDAY NIGHT ALTHOUGH AT THIS POINT I THINK
THAT IS A LOW PROBABILITY SCENARIO AND I HAVE NOT INCLUDED ZL IN
THE GRIDDED FORECAST. AT THIS POINT IT APPEARS THAT CLOUDS WILL
PERSIST THROUGH FRIDAY. WITH PLENTY OF CLOUDS WE ARE NOT EXPECTING
MUCH DIURNAL VARIATION IN TEMPERATURES THROUGH FRIDAY WITH HIGHS
MAINLY 30 TO 35 AND LOWS 20 TO 25 IN MOST PLACES.
BEST CHANCE TO SEE ANY SUNSHINE MIGHT BE EARLY SATURDAY BEFORE
CLOUDS AHEAD OF THE NEXT SYSTEM STREAM NORTHEAST ACROSS THE AREA
DURING THE AFTERNOON. SATURDAY SHOULD BE DRY WITH TEMPERATURES
AGAIN MAINLY IN THE 30S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
1 PM UPDATE..
FOLLOWED WPC GUIDANCE FOR THE MOST PART. SAT NGT AND SUN SOME
LIGHT SNOW WITH AN INVERTED TROF FROM A COASTAL STORM WELL OUT TO
SEA. SNOW ACCUMULATIONS WILL BE MOSTLY 2 INCHES OR LESS.
DRY SUN NGT AND MON WITH A MILD SFC HIGH. MON NGT AND TUE MODELS
NOW TRYING TO BRING A WEAK COASTAL STORM NE INTO THE AREA WITH
MIXED PRECIP. ADDED SOME LOW CHC POPS.
WED A STRONG OCCLUDED FRONT LIFTS NE AHEAD OF A LARGE BOMBING
STACKED LOW IN THE MIDWEST. WARM AIR SO PRECIP MOSTLY RAIN. THIS
WILL NEED TO BE WATCHED FIRST FOR RAIN AMOUNTS AND POSSIBLY
FLOODING AND SECOND FOR STRONG GUSTY WINDS.
ON THE TAIL END OF THE STEADY RAIN IT WILL CHANGE OVER TO SNOW WED
NGT AND STAY COLD THE REST OF THE WEEK WITH WRAP AROUND SNOW.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
MVFR CONDITIONS WILL GENERALLY BE THE RULE THROUGH THURSDAY
AFTERNOON AS LOW LEVEL MOISTURE AND SNOW SHOWERS / FLURRIES
CONTINUE TO AFFECT THE AREA IN ASSOCIATION WITH AN UPPER LEVEL LOW
AND SOME LAKE EFFECT.
AS FAR AS SPECIFICS, WE EXPECT FLURRIES AND SNOW SHOWERS TO BE
MOST PERSISTENT FOR KSYR AND KRME. KRME SHOULD SEE MAINLY IFR
CEILINGS AND MVFR VISBYS IN FLURRIES THROUGH THIS EVENING WITH
CEILINGS IMPROVING TO MVFR LATER TONIGHT INTO TOMORROW. KSYR
SHOULD BE MAINLY MVFR BUT COULD GO IFR VISBYS AT TIMES LATER TONIGHT
INTO TOMORROW IF HEAVIER SNOW SHOWERS AFFECT THE AREA.
FURTHER SOUTH, STEADIER PRECIP SHOULD CONTINUE TO DIMINISH THIS
EVENING AND WE EXPECT MAINLY MVFR CEILINGS AND VFR VISBYS THROUGH
THE TAF PERIOD FOR KELM, KITH, AND KBGM WHILE KAVP REMAINS VFR.
OUTLOOK...
THUR NIGHT TO FRI... MAINLY VFR. MVFR/IFR RESTRICTIONS ARE PSBL AT
KRME/KSYR/KITH/KBGM DUE TO CIGS AND AT TIMES WITH -SHSN.
FRI NGT TO SAT...VFR.
SAT NGT AND SUN...MVFR/IFR IN LIGHT SNOW.
SUN NGT AND MON...VFR/MVFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE
SHORT TERM...MSE
LONG TERM...TAC
AVIATION...PCF/TAC
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
102 PM EST TUE DEC 16 2014
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST THIS AFTERNOON AND MOVE
THROUGH THE AREA TONIGHT. HIGH PRESSURE WILL BUILD IN FROM THE
NORTHWEST WEDNESDAY THROUGH FRIDAY. DEVELOPING LOW PRESSURE WILL
MOVE ALONG THE COAST SATURDAY INTO SUNDAY. HIGH PRESSURE IS
EXPECTED TO BUILD OVER THE AREA MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1 PM TUESDAY...BAND OF SHOWERS CONTINUES TO SLOWLY APPROACH
OUR WESTERN CWA AND LATEST 3KM HRRR CONTINUES TO HANDLE THE
PRECIPITATION QUITE WELL. BROKEN BAND OF LIGHT TO OCCASIONALLY
MODERATE SHOWERS WILL CROSS THE CWA FROM ROUGHLY 19Z TO ABOUT 04Z
TONIGHT BEFORE MOVING OFFSHORE. LOWER CLOUDS WILL ACCOMPANY THE
SHOWERS AS THE FILTERED SUNSHINE OF THE MORNING WILL BE REPLACED
BY LOWER OVERCAST. TEMPERATURES LIKEWISE WILL LIKELY FALL A FEW
DEGREES DURING THE LATE AFTERNOON HOURS. INSTABILITY IS VERY
LIMITED AND TO NOT EXPECT THUNDER AT THIS TIME.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
AS OF 330 AM TUESDAY...MODELS REMAIN IN FAIRLY CLOSE AGREEMENT WITH
SHRT WV TROF AND ASSCTD SFC COLD FRONT MOVING ACROSS AREA OVERNIGHT.
PER NEAR TERM DISCUSSION...MAIN THREAT OF PCPN WILL BE OVER ERN HALF
OF AREA EARLY EVENING WITH HIGHEST POPS AROUND 50%. PCPN WILL PUSH
OFF COAST BY AROUND MIDNIGHT WITH CLEARING SKIES OVERNIGHT.
MIN TEMPS LOW TO MID 40S INLAND AND AROUND 50 OUTER BANKS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 325 AM TUE...LONG TERM PERIOD WILL FEATURE A FAIRLY ACTIVE
AND CHANGEABLE WEATHER PATTERN...WITH A SIGNIFICANT STORM SYSTEM
POSSIBLE FOR THE WEEKEND. SFC HIGH PRESSURE WILL BUILD INTO
EASTERN NC FROM THE W/NW WED THROUGH FRI. LOW LEVEL THICKNESS
VALUES AND SUNNY SKIES SUPPORT HIGHS 55-60DEG WED WITH LOW LEVEL
W/NW FLOW. LOW LEVEL THICKNESS VALUES SUPPORT HIGHS IN THE UPPER
40S/MID 50S FOR THU AND FRI WITH SHORTWAVE MOVING NORTH OF THE
AREA AND ZONAL FLOW ACROSS ENC.
A SIGNIFICANT SYSTEM MAY IMPACT THE REGION THIS WEEKEND. THE
PREVIOUS FAVORED ECMWF...NOW BEGINNING TO TREND SIMILAR TO THE
GFS...DEPICTING A WEAKER AND SLOWER SOLUTION. MODELS SHOW WEAK SFC
MOVING THROUGH MEXICO AND SOUTHERN TX THU NIGHT AND FRI... THEN
INTO THE DEEP SOUTH/NORTHERN GULF REGION SATURDAY...EVENTUALLY
INTENSIFYING OFF THE SE COAST LATE SAT INTO SUN NIGHT. THOUGH MUCH
UNCERTAINTY REMAINS WITH TRACK AND INTENSITY OF LOW...THERE WILL BE
THE POTENTIAL FOR HEAVY RAIN...STRONG WINDS...AND MINOR COASTAL
IMPACTS THIS WEEKEND...INCLUDING MINOR WATER LEVEL RISES AND ROUGH
SURF. STILL LOOKS LIKE THE FIRST PART OF THE WEEKEND WILL BE WET
AND CONTINUED LIKELY POPS...WITH MOISTURE TAPERING OFF LATE SUN.
AN ISOLATED CHANCE OF TSTMS STILL POSSIBLE SAT THOUGH VERY
DEPENDENT ON EVENTUAL TRACK OF LOW...WITH BEST CHANCE ALONG THE
COAST AND OFFSHORE.
BOTH GFS/ECMWF SHOW A SOUTHERN STREAM DEVELOPING EARLY NEXT WEEK
AHEAD OF THE UPPER TROUGH...AS THE WEEKEND SFC LOW LIFTS NE OFF
THE NEW ENGLAND COAST. BELOW NORMAL TEMPS EXPECTED FOR SUN/MON
WITH HIGHS IN THE UPPER 40S/LOW 50S AND OVERNIGHT LOWS IN THE 30S.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
SHORT TERM /THROUGH 12Z WEDNESDAY/...
AS OF 1235 PM TUESDAY...LOWER CEILINGS AND LIGHT SHOWERS CONTINUE
TO APPROACH THE CWA. HAVE INCLUDED A PERIOD FROM ROUGHLY 19Z
THROUGH ABOUT MIDNIGHT TONIGHT OF MVFR CEILINGS WITH SHOWERS IN
THE VICINITY. CONDITIONS SHOULD IMPROVE RAPIDLY AFTER MIDNIGHT
WITH VFR CONDITIONS PREVAILING THROUGH WEDNESDAY. SOUTHWEST WINDS
BECOME NORTHWEST AFTER MIDNIGHT AND CONTINUE THROUGH WEDNESDAY.
LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
AS OF 325 AM TUE...PRED VFR CONDITIONS EXPECTED THROUGH MOST OF
THE PERIOD. THERE WILL BE THE POTENTIAL FOR WIDESPREAD SUB-VFR
CONDITIONS TO DEVELOP SATURDAY...AS LOW PRESSURE SYSTEM IS
EXPECTED TO IMPACT EASTERN NC.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 1 PM TUESDAY...SOUTHEAST WINDS WILL GRADUALLY BECOME
SOUTHWEST AND INCREASE THIS AFTERNOON. ALREADY SEEING GUSTS TO 16
KNOTS AT CAPE LOOKOUT AND 18 KNOTS AT THE CAPE HATTERAS COAST
GUARD STATION. SEAS REMAIN AROUND 2 FEET. EXPECT TO SEE WIDESPREAD
WINDS OF 15 TO 20 KNOTS BY LATE IN THE DAY. ADJUSTED FCST SEAS
WITH LATEST NWPS...INDICATING PERIOD OF 6 FT HEIGHTS FOR OUTER
PORTIONS OF SRN AND CENTRAL WATERS TONIGHT.
LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 325 AM TUE...SFC HIGH PRESSURE WILL BUILD INTO THE REGION FROM
THE W/NW WED THROUGH FRI...RESULTING IN W/NWLY FLOW 10-20KT AND
SEAS 2-4FT. TRENDED WITH WAVEWATCH LATE WED THROUGH FRI...THINKING
THAT LOCAL NWPS IS STILL SLIGHTLY OVERDONE WITH THE OFFSHORE FLOW.
UNCERTAINTY INCREASES THIS WEEKEND WITH THE POTENTIAL FOR ANOTHER
COASTAL LOW DEVELOPING AND IMPACTING THE EASTERN NC WATERS.
PREVIOUS FAVORED MODEL ECMWF...NOW THE 00Z RUN COMING IN MORE
SIMILAR TO THE GFS...DEPICTING A SLIGHTLY WEAKER AND SLOWER SFC
LOW MOVING ALONG THE NC COAST SUN AND SUN NIGHT. CONFIDENCE
REMAINS LOW BUT THERE WILL BE THE POTENTIAL FOR STRONG WINDS TO
GALE FORCE AND HAZARDOUS SEAS THIS WEEKEND.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 5 AM EST
WEDNESDAY FOR AMZ152-154-156-158.
&&
$$
SYNOPSIS...JBM
NEAR TERM...CTC
SHORT TERM...JBM
LONG TERM...CQD
AVIATION...CTC/CQD
MARINE...JBM/CTC/CQD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1050 AM EST TUE DEC 16 2014
.SYNOPSIS...A COLD FRONT WILL PUSH EAST THROUGH THE REGION TODAY.
HIGH PRESSURE WILL BUILD SLOWLY INTO THE AREA THROUGH FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 AM TUESDAY...
MORNING UPDATE WILL TWEAK POPS UPWARDS TO LIKELY IN THE CENTRAL AND
EAST INTO THE MID AFTERNOON AND DOWNWARD IN THE WEST AS THE
PREFRONTAL BAND RACES EAST. ALSO ADJUSTING TEMP TRENDS AS WARM AIR
ADVECTION AHEAD OF SHOWERS HAS PRODUCED A WIDE RANGE OF TEMPS...FROM
MID 40S TO UPPER 50S.
TODAY: WEAKENING SOUTHERN STREAM TROUGH ENTERING THE OHIO VALLEY
WILL WILL MOVE EAST-NORTHEASTWARD INTO THE GREAT LAKES AND MID-
ATLANTIC REGION TODAY. PRE-FRONTAL BAND OF CONVECTION(CURRENTLY
APPROACHING THE MOUNTAINS)EMBEDDED IN THE LLJ ASSOCIATED WITH THE
WARM CONVEYOR BELT WILL TRANSLATE QUICKLY EASTWARD ACROSS THE AREA
BETWEEN 12 TO 21Z...BRINGING A BRIEF 2 TO 3 HOUR WINDOW OF SCATTERED
SHOWERS AS MOISTURE PROFILES CONTINUE TO LOOK MODEST...PRIMARILY
CONFINED TO THE 850-700 MB LAYER. AS SUCH...HAVE CHOSEN TO KEEP
POPS AT HIGH CHANCE WITH ONLY LIGHT PRECIP AMOUNTS EXPECTED OF A
TENTH OF AN OR LESS. AS THE CONVEYOR BELT SHIFTS OFFSHORE...MID-
LEVEL DRYING WILL RACE EASTWARD...AHEAD OF THE SFC COLD FRONTAL
PASSAGE WHICH WILL RESULT ONLY ISOLATED SHOWERS ALONG THE IMMEDIATE
FRONT. CANNOT RULE OUT A RUMBLE OF THUNDER AS SOUNDINGS SHOW VERY
WEAK INSTABILITY ALOFT (200-350J/KG OF MUCAPE)...BUT WILL NOT
INCLUDE ANY MENTION AT THIS TIME.
BOTH THE GFS AND NAM BUFR SOUNDINGS SUGGEST THAT THE RAIN AND
LINGERING LOW CLOUDS WILL SUPPRESS TEMPERATURES IN THE MID/UPPER
50S...COOLER THAN PREVIOUS FORECAST AND IN-LINE WITH COOLER MET
STATISTICAL GUIDANCE. THE EXCEPTION MAY BE ACROSS THE FAR SE...WHERE
LATER ARRIVAL OF PRECIP COULD ALLOW TEMPS TO WARM INTO THE LOWER
60S.
TONIGHT: CLEARING WILL SPREAD EASTWARD LATE THIS EVENING IN THE WAKE
OF THE COLD FRONT. A LIGHT NWLY BREEZE WILL KEEP THINGS STIRRED UP
OVERNIGHT WITH RESULTANT WEAK CAA SUPPORTING OVERNIGHT LOWS IN THE
MID/UPPER 30S NW TO LOWER 40S SE.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 240 AM TUESDAY...
FAIR WEATHER IS EXPECTED ON WEDNESDAY AS THE UPPER FLOW BECOMES
ZONAL BEHIND THE UPPER TROUGH THAT MOVES OFF THE COAST TUESDAY
NIGHT. AT THE SURFACE...HIGH PRESSURE OVER THE CENTRAL US WILL BE
VERY SLOW TO BUILD EASTWARD WITH NEUTRAL TEMPERATURE ADVECTION AT
850MB NOTED...WHICH SHOULD SUPPORT NEAR TO SLIGHTLY ABOVE NORMAL
HIGHS IN THE MID TO UPPER 50S.
AN ACTIVE PACIFIC WAVE TRAIN MOVING ONSHORE ACROSS CALIFORNIA AND
THEN THROUGH THE SOUTHWEST WILL REINVIGORATE THE PACIFIC JET THAT
EXTENDS ACROSS THE SOUTHERN CONUS. AN OPAQUE CIRRUS SHIELD COULD
SPREAD EAST INTO THE AREA AS EARLY AS WEDNESDAY AFTERNOON BUT
DEFINITELY BY WEDNESDAY NIGHT. THIS CLOUD COVER SHOULD TEMPER MIN
TEMPS...AND COULD QUITE POSSIBLY RESULT IN A NON-DIURNAL TEMPERATURE
TREND WITH TEMPERATURES HOLDING STEADY OR RISING AFTER MIDNIGHT.
LOWS IN MIDS 30S TO UPPER 30S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 245 AM TUESDAY...
THROUGH FRIDAY: SURFACE HIGH PRESSURE WILL CONTINUE TO RIDGE INTO
THE REGION THROUGH FRIDAY. THE ZONAL FLOW ALOFT WILL SLOWLY BECOME
MORE AMPLIFIED THROUGH THIS PERIOD...WITH GENERALLY WEST-NORTHWEST
FLOW OVER CENTRAL NC. EXPECT DRY WEATHER TO DOMINATE DURING THIS
TIME...HOWEVER THE MODELS ARE TRYING TO GENERATE SOME LIGHT PRECIP
FOR A BRIEF PERIOD ON THURSDAY...MAINLY IN THE FAR NW. FOR NOW WILL
KEEP THIS PART OF THE FORECAST DRY UNTIL THE MODELS SHOW A BIT MORE
RUN-TO-RUN CONSISTENCY WITH THE PRECIP. HIGHS IN THE UPPER 40S NORTH
TO MAINLY MID 50S SOUTH THURSDAY AND FRIDAY. EXPECT THURSDAY NIGHT
LOWS MAINLY IN THE LOW TO MID 30S.
FRIDAY NIGHT SATURDAY NIGHT: EXPECT RAPIDLY INCREASING CLOUDINESS
FRIDAY NIGHT AS A LOW PRESSURE SYSTEM APPROACHES FROM THE GULF. THE
INCREASED CLOUD COVER MAY YIELD LOWS A FEW DEGREES HIGHER THAN
PREVIOUS NIGHTS...GENERALLY IN THE MID 30S. IT APPEARS AS THOUGH THE
MODELS HAVE TRENDED TOWARD ONE ANOTHER OVER THE PAST FEW RUNS WITH
RESPECT TO THE APPROACHING UPPER LEVEL TROUGH/SHORTWAVE AND SURFACE
LOW. THE ECMWF IS STILL A BIT MORE AMPLIFIED THAN THE GFS ALOFT...
BUT THEY ARE MUCH CLOSER THAN PREVIOUS RUNS. THE GFS IS STILL JUST A
BIT FASTER...LARGELY DUE TO THE TROUGH BEING LESS AMPLIFIED...BUT
BOTH HAVE PRECIP MOVING INTO THE AREA FROM THE WEST-SOUTHWEST BY 12Z
SATURDAY. FOR NOW EXPECT TEMPS ACROSS OUR AREA TO REMAIN ABOVE
FREEZING FRIDAY NIGHT...THUS DO NOT EXPECT ANY WINTERY PRECIP AT
THIS TIME. HOWEVER...IF THE HIGH RIDGING IN FROM THE NE FRIDAY NIGHT
RESULTS IN TEMPS FALLING BELOW FREEZING THE CHANCE FOR PRECIP OF THE
FROZEN VARIETY MAY BE IN THE REALM OF POSSIBILITY. THE SURFACE LOW
IS EXPECTED TO MOVE ALONG THE GULF COAST AND UP ALONG THE CAROLINA
COAST SATURDAY AND SATURDAY NIGHT AND PRECIP CHANCES AND AMOUNT WILL
DEPEND ON THE EXACT TRACK THE LOW TAKES AS IT MOVES THROUGH THE
REGION. GIVEN THE CURRENT LOW TRACK...ANY THUNDERSTORMS WILL BE
LIMITED TO THE FAR SOUTHEAST AND COASTAL AREAS. TEMPS WILL ALSO
DEPEND ON WHERE THE LOW TRACKS...BUT FOR NOW EXPECT HIGHS AROUND 40
DEGREES IN THE NW TO LOW 50S IN THE SE. OVERNIGHT LOWS VERY SIMILAR
TO FRIDAY NIGHT...MAINLY IN THE MID 30S.
SUNDAY AND MONDAY: THE MAIN UPPER LEVEL SHORTWAVE MOVES OUT OF THE
REGION TO THE NORTHEAST SUNDAY MORNING...WHILE THE SURFACE LOW
REMAINS OFF THE COAST OF THE CAROLINAS THROUGH THE DAY. THE MODELS
INDICATE THE CHANCE FOR SOME LIGHT PRECIP TO LINGER ACROSS THE EAST
THROUGH SUNDAY AS THE SURFACE LOW REMAINS IN CLOSE PROXIMITY... WITH
CHANCES DECREASING LATE SUNDAY AND SUNDAY NIGHT AS THE LOW RAPIDLY
MOVES OFF TO THE NE AND AWAY FROM NC. FOR NOW...EXPECT SUNDAY NIGHT
AND MONDAY TO BE DRY. HIGHS SUNDAY AND MONDAY WILL GENERALLY BE IN
THE MID 40S NORTH TO AROUND 50S DEGREES SOUTH...WITH OVERNIGHT LOWS
IN THE UPPER 20S TO LOW 30S.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 648 AM TUESDAY...
24 HOUR TAF PERIOD: LIFR TO IFR RESTRICTIONS IN FOG HAVE DEVELOPED
ACROSS THE EAST. HRRR SUGGESTS THESE VISIBILITY RESTRICTIONS AND LOW
CLOUDS COULD LINGER THROUGH THE LATE MORNING ~15 TO 16Z. A PRE-
FRONTAL BAND OF SHOWERS WILL CROSS THE AREA BETWEEN 14 TO 17Z IN THE
WEST...EXITING EASTERN TERMINALS AOA 21Z. FCST SOUNDINGS AND
UPSTREAM TRENDS SUGGEST CIGS WILL LOWER TO MVFR WITHIN THE BAND OF
SHOWERS AND WILL REMAIN SUB-VFR UNTIL THE TRAILING SFC COLD FRONT
CROSSES THE AREA DURING THE EARLY EVENING...WITH CLEARING SPREADING
WEST TO EAST BETWEEN 00 TO 06Z.
OUTLOOK...VFR CONDITIONS SHOULD DOMINATE WEDNESDAY THROUGH EARLY
FRIDAY. A LOW PRESSURE SYSTEM TRACKING FROM THE GULF OF MEXICO
NORTHEASTWARD ALONG THE SOUTHEAST COAST WILL RESULT IN ADVERSE
AVIATION CONDITIONS LATE FRIDAY AND INTO THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...MLM/CBL
SHORT TERM...CBL
LONG TERM...KC
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
949 AM EST TUE DEC 16 2014
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND MOVE THROUGH THE
AREA TONIGHT. HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST
WEDNESDAY THROUGH FRIDAY. DEVELOPING LOW PRESSURE WILL MOVE ALONG
THE COAST SATURDAY INTO SUNDAY. HIGH PRESSURE IS EXPECTED TO BUILD
OVER THE AREA MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 945 AM TUESDAY...FORECAST ON TRACK FOR THIS AFTERNOON AS THE
3KM HRRR AND NSSL WRF INDICATE BROKEN LINE OF SHOWERS ARRIVE IN
THE 18Z-21Z TIMEFRAME AND WORKING ACROSS THE CWA INTO EARLY
EVENING. INSTABILITY WILL REMAIN LIMITED AS DEWPOINTS WILL HAVE
MINIMAL CHANCE TO RECOVER THIS AFTERNOON AND ANY THUNDER WILL BE
ELEVATED AS THE BEST UPPER SUPPORT MOVES TO THE NORTH OF THE
REGION. KEPT POPS IN THE HIGH CHANCE RANGE BUT QPF TOTALS WILL BE
RELATIVELY LIGHT ON THE ORDER OF 0.1 TO 0.2 INCH. TEMPERATURES ARE
RISING QUICKLY AND SHOULD BE WELL INTO THE 60S BY MIDDAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
AS OF 330 AM TUESDAY...MODELS REMAIN IN FAIRLY CLOSE AGREEMENT WITH
SHRT WV TROF AND ASSCTD SFC COLD FRONT MOVING ACROSS AREA OVERNIGHT.
PER NEAR TERM DISCUSSION...MAIN THREAT OF PCPN WILL BE OVER ERN HALF
OF AREA EARLY EVENING WITH HIGHEST POPS AROUND 50%. PCPN WILL PUSH
OFF COAST BY AROUND MIDNIGHT WITH CLEARING SKIES OVERNIGHT.
MIN TEMPS LOW TO MID 40S INLAND AND AROUND 50 OUTER BANKS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 325 AM TUE...LONG TERM PERIOD WILL FEATURE A FAIRLY ACTIVE
AND CHANGEABLE WEATHER PATTERN...WITH A SIGNIFICANT STORM SYSTEM
POSSIBLE FOR THE WEEKEND. SFC HIGH PRESSURE WILL BUILD INTO
EASTERN NC FROM THE W/NW WED THROUGH FRI. LOW LEVEL THICKNESS
VALUES AND SUNNY SKIES SUPPORT HIGHS 55-60DEG WED WITH LOW LEVEL
W/NW FLOW. LOW LEVEL THICKNESS VALUES SUPPORT HIGHS IN THE UPPER
40S/MID 50S FOR THU AND FRI WITH SHORTWAVE MOVING NORTH OF THE
AREA AND ZONAL FLOW ACROSS ENC.
A SIGNIFICANT SYSTEM MAY IMPACT THE REGION THIS WEEKEND. THE
PREVIOUS FAVORED ECMWF...NOW BEGINNING TO TREND SIMILAR TO THE
GFS...DEPICTING A WEAKER AND SLOWER SOLUTION. MODELS SHOW WEAK SFC
MOVING THROUGH MEXICO AND SOUTHERN TX THU NIGHT AND FRI... THEN
INTO THE DEEP SOUTH/NORTHERN GULF REGION SATURDAY...EVENTUALLY
INTENSIFYING OFF THE SE COAST LATE SAT INTO SUN NIGHT. THOUGH MUCH
UNCERTAINTY REMAINS WITH TRACK AND INTENSITY OF LOW...THERE WILL BE
THE POTENTIAL FOR HEAVY RAIN...STRONG WINDS...AND MINOR COASTAL
IMPACTS THIS WEEKEND...INCLUDING MINOR WATER LEVEL RISES AND ROUGH
SURF. STILL LOOKS LIKE THE FIRST PART OF THE WEEKEND WILL BE WET
AND CONTINUED LIKELY POPS...WITH MOISTURE TAPERING OFF LATE SUN.
AN ISOLATED CHANCE OF TSTMS STILL POSSIBLE SAT THOUGH VERY
DEPENDENT ON EVENTUAL TRACK OF LOW...WITH BEST CHANCE ALONG THE
COAST AND OFFSHORE.
BOTH GFS/ECMWF SHOW A SOUTHERN STREAM DEVELOPING EARLY NEXT WEEK
AHEAD OF THE UPPER TROUGH...AS THE WEEKEND SFC LOW LIFTS NE OFF
THE NEW ENGLAND COAST. BELOW NORMAL TEMPS EXPECTED FOR SUN/MON
WITH HIGHS IN THE UPPER 40S/LOW 50S AND OVERNIGHT LOWS IN THE 30S.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH 12Z WEDNESDAY/...
AS OF 630 AM TUESDAY...PATCHY FOG AND SOME STRATUS AFFECTING TAF
SITES EARLY THIS MORNING...MAINLY WITH MVFR VSBYS BUT LOCAL LIFR AT
KOAJ. CONDITIONS IMPROVING TO VFR 13Z-14Z AND PREVAILING REST OF TAF
PERIOD OUTSIDE OF SCT SHRA ACTIVITY LATE AFTN INTO EARLY EVENING. SW
WINDS WILL INCREASE TO AROUND 10 KT TODAY AND SHIFT TO W BEHIND
FRONTAL PASSAGE THIS EVENING.
LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 325 AM TUE...PRED VFR CONDITIONS EXPECTED THROUGH MOST OF THE
PERIOD. THERE WILL BE THE POTENTIAL FOR WIDESPREAD SUB-VFR
CONDITIONS TO DEVELOP SATURDAY...AS LOW PRESSURE SYSTEM IS
EXPECTED TO IMPACT EASTERN NC.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 945 AM TUESDAY...LIGHT SOUTHWEST WINDS CONTINUE TO AREA
WATERS WITH SEAS AROUND 2 FEET. WINDS SHOULD VEER TO SOUTHWEST
AHEAD OF AN ONCOMING COLD FRONT AND INCREASE TO 15 TO 20 KNOTS BY
LATE IN THE DAY. ADJUSTED FCST SEAS WITH LATEST
NWPS...INDICATING PERIOD OF 6 FT HEIGHTS FOR OUTER PORTIONS OF SRN
AND CENTRAL WATERS TONIGHT.
LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 325 AM TUE...SFC HIGH PRESSURE WILL BUILD INTO THE REGION FROM
THE W/NW WED THROUGH FRI...RESULTING IN W/NWLY FLOW 10-20KT AND
SEAS 2-4FT. TRENDED WITH WAVEWATCH LATE WED THROUGH FRI...THINKING
THAT LOCAL NWPS IS STILL SLIGHTLY OVERDONE WITH THE OFFSHORE FLOW.
UNCERTAINTY INCREASES THIS WEEKEND WITH THE POTENTIAL FOR ANOTHER
COASTAL LOW DEVELOPING AND IMPACTING THE EASTERN NC WATERS.
PREVIOUS FAVORED MODEL ECMWF...NOW THE 00Z RUN COMING IN MORE
SIMILAR TO THE GFS...DEPICTING A SLIGHTLY WEAKER AND SLOWER SFC
LOW MOVING ALONG THE NC COAST SUN AND SUN NIGHT. CONFIDENCE
REMAINS LOW BUT THERE WILL BE THE POTENTIAL FOR STRONG WINDS TO
GALE FORCE AND HAZARDOUS SEAS THIS WEEKEND.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 5 AM EST
WEDNESDAY FOR AMZ152-154-156-158.
&&
$$
SYNOPSIS...JBM
NEAR TERM...CTC
SHORT TERM...JBM
LONG TERM...CQD
AVIATION...JBM/CQD
MARINE...JBM/CTC/CQD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
647 AM EST TUE DEC 16 2014
.SYNOPSIS...A COLD FRONT WILL PUSH EAST THROUGH THE REGION TODAY.
HIGH PRESSURE WILL BUILD SLOWLY INTO THE AREA THROUGH FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 AM TUESDAY...
TODAY: WEAKENING SOUTHERN STREAM TROUGH ENTERING THE OHIO VALLEY
WILL WILL MOVE EAST-NORTHEASTWARD INTO THE GREAT LAKES AND MID-
ATLANTIC REGION TODAY. PRE-FRONTAL BAND OF CONVECTION(CURRENTLY
APPROACHING THE MOUNTAINS)EMBEDDED IN THE LLJ ASSOCIATED WITH THE
WARM CONVEYOR BELT WILL TRANSLATE QUICKLY EASTWARD ACROSS THE AREA
BETWEEN 12 TO 21Z...BRINGING A BRIEF 2 TO 3 HOUR WINDOW OF SCATTERED
SHOWERS AS MOISTURE PROFILES CONTINUE TO LOOK MODEST...PRIMARILY
CONFINED TO THE 850-700 MB LAYER. AS SUCH...HAVE CHOSEN TO KEEP
POPS AT HIGH CHANCE WITH ONLY LIGHT PRECIP AMOUNTS EXPECTED OF A
TENTH OF AN OR LESS. AS THE CONVEYOR BELT SHIFTS OFFSHORE...MID-
LEVEL DRYING WILL RACE EASTWARD...AHEAD OF THE SFC COLD FRONTAL
PASSAGE WHICH WILL RESULT ONLY ISOLATED SHOWERS ALONG THE IMMEDIATE
FRONT. CANNOT RULE OUT A RUMBLE OF THUNDER AS SOUNDINGS SHOW VERY
WEAK INSTABILITY ALOFT (200-350J/KG OF MUCAPE)...BUT WILL NOT
INCLUDE ANY MENTION AT THIS TIME.
BOTH THE GFS AND NAM BUFR SOUNDINGS SUGGEST THAT THE RAIN AND
LINGERING LOW CLOUDS WILL SUPPRESS TEMPERATURES IN THE MID/UPPER
50S...COOLER THAN PREVIOUS FORECAST AND IN-LINE WITH COOLER MET
STATISTICAL GUIDANCE. THE EXCEPTION MAY BE ACROSS THE FAR SE...WHERE
LATER ARRIVAL OF PRECIP COULD ALLOW TEMPS TO WARM INTO THE LOWER
60S.
TONIGHT: CLEARING WILL SPREAD EASTWARD LATE THIS EVENING IN THE WAKE
OF THE COLD FRONT. A LIGHT NWLY BREEZE WILL KEEP THINGS STIRRED UP
OVERNIGHT WITH RESULTANT WEAK CAA SUPPORTING OVERNIGHT LOWS IN THE
MID/UPPER 30S NW TO LOWER 40S SE.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 240 AM TUESDAY...
FAIR WEATHER IS EXPECTED ON WEDNESDAY AS THE UPPER FLOW BECOMES
ZONAL BEHIND THE UPPER TROUGH THAT MOVES OFF THE COAST TUESDAY
NIGHT. AT THE SURFACE...HIGH PRESSURE OVER THE CENTRAL US WILL BE
VERY SLOW TO BUILD EASTWARD WITH NEUTRAL TEMPERATURE ADVECTION AT
850MB NOTED...WHICH SHOULD SUPPORT NEAR TO SLIGHTLY ABOVE NORMAL
HIGHS IN THE MID TO UPPER 50S.
AN ACTIVE PACIFIC WAVE TRAIN MOVING ONSHORE ACROSS CALIFORNIA AND
THEN THROUGH THE SOUTHWEST WILL REINVIGORATE THE PACIFIC JET THAT
EXTENDS ACROSS THE SOUTHERN CONUS. AN OPAQUE CIRRUS SHIELD COULD
SPREAD EAST INTO THE AREA AS EARLY AS WEDNESDAY AFTERNOON BUT
DEFINITELY BY WEDNESDAY NIGHT. THIS CLOUD COVER SHOULD TEMPER MIN
TEMPS...AND COULD QUITE POSSIBLY RESULT IN A NON-DIURNAL TEMPERATURE
TREND WITH TEMPERATURES HOLDING STEADY OR RISING AFTER MIDNIGHT.
LOWS IN MIDS 30S TO UPPER 30S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 245 AM TUESDAY...
THROUGH FRIDAY: SURFACE HIGH PRESSURE WILL CONTINUE TO RIDGE INTO
THE REGION THROUGH FRIDAY. THE ZONAL FLOW ALOFT WILL SLOWLY BECOME
MORE AMPLIFIED THROUGH THIS PERIOD...WITH GENERALLY WEST-NORTHWEST
FLOW OVER CENTRAL NC. EXPECT DRY WEATHER TO DOMINATE DURING THIS
TIME...HOWEVER THE MODELS ARE TRYING TO GENERATE SOME LIGHT PRECIP
FOR A BRIEF PERIOD ON THURSDAY...MAINLY IN THE FAR NW. FOR NOW WILL
KEEP THIS PART OF THE FORECAST DRY UNTIL THE MODELS SHOW A BIT MORE
RUN-TO-RUN CONSISTENCY WITH THE PRECIP. HIGHS IN THE UPPER 40S NORTH
TO MAINLY MID 50S SOUTH THURSDAY AND FRIDAY. EXPECT THURSDAY NIGHT
LOWS MAINLY IN THE LOW TO MID 30S.
FRIDAY NIGHT SATURDAY NIGHT: EXPECT RAPIDLY INCREASING CLOUDINESS
FRIDAY NIGHT AS A LOW PRESSURE SYSTEM APPROACHES FROM THE GULF. THE
INCREASED CLOUD COVER MAY YIELD LOWS A FEW DEGREES HIGHER THAN
PREVIOUS NIGHTS...GENERALLY IN THE MID 30S. IT APPEARS AS THOUGH THE
MODELS HAVE TRENDED TOWARD ONE ANOTHER OVER THE PAST FEW RUNS WITH
RESPECT TO THE APPROACHING UPPER LEVEL TROUGH/SHORTWAVE AND SURFACE
LOW. THE ECMWF IS STILL A BIT MORE AMPLIFIED THAN THE GFS ALOFT...
BUT THEY ARE MUCH CLOSER THAN PREVIOUS RUNS. THE GFS IS STILL JUST A
BIT FASTER...LARGELY DUE TO THE TROUGH BEING LESS AMPLIFIED...BUT
BOTH HAVE PRECIP MOVING INTO THE AREA FROM THE WEST-SOUTHWEST BY 12Z
SATURDAY. FOR NOW EXPECT TEMPS ACROSS OUR AREA TO REMAIN ABOVE
FREEZING FRIDAY NIGHT...THUS DO NOT EXPECT ANY WINTERY PRECIP AT
THIS TIME. HOWEVER...IF THE HIGH RIDGING IN FROM THE NE FRIDAY NIGHT
RESULTS IN TEMPS FALLING BELOW FREEZING THE CHANCE FOR PRECIP OF THE
FROZEN VARIETY MAY BE IN THE REALM OF POSSIBILITY. THE SURFACE LOW
IS EXPECTED TO MOVE ALONG THE GULF COAST AND UP ALONG THE CAROLINA
COAST SATURDAY AND SATURDAY NIGHT AND PRECIP CHANCES AND AMOUNT WILL
DEPEND ON THE EXACT TRACK THE LOW TAKES AS IT MOVES THROUGH THE
REGION. GIVEN THE CURRENT LOW TRACK...ANY THUNDERSTORMS WILL BE
LIMITED TO THE FAR SOUTHEAST AND COASTAL AREAS. TEMPS WILL ALSO
DEPEND ON WHERE THE LOW TRACKS...BUT FOR NOW EXPECT HIGHS AROUND 40
DEGREES IN THE NW TO LOW 50S IN THE SE. OVERNIGHT LOWS VERY SIMILAR
TO FRIDAY NIGHT...MAINLY IN THE MID 30S.
SUNDAY AND MONDAY: THE MAIN UPPER LEVEL SHORTWAVE MOVES OUT OF THE
REGION TO THE NORTHEAST SUNDAY MORNING...WHILE THE SURFACE LOW
REMAINS OFF THE COAST OF THE CAROLINAS THROUGH THE DAY. THE MODELS
INDICATE THE CHANCE FOR SOME LIGHT PRECIP TO LINGER ACROSS THE EAST
THROUGH SUNDAY AS THE SURFACE LOW REMAINS IN CLOSE PROXIMITY... WITH
CHANCES DECREASING LATE SUNDAY AND SUNDAY NIGHT AS THE LOW RAPIDLY
MOVES OFF TO THE NE AND AWAY FROM NC. FOR NOW...EXPECT SUNDAY NIGHT
AND MONDAY TO BE DRY. HIGHS SUNDAY AND MONDAY WILL GENERALLY BE IN
THE MID 40S NORTH TO AROUND 50S DEGREES SOUTH...WITH OVERNIGHT LOWS
IN THE UPPER 20S TO LOW 30S.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 648 AM TUESDAY...
24 HOUR TAF PERIOD: LIFR TO IFR RESTRICTIONS IN FOG HAVE DEVELOPED
ACROSS THE EAST. HRRR SUGGESTS THESE VISIBILITY RESTRICTIONS AND LOW
CLOUDS COULD LINGER THROUGH THE LATE MORNING ~15 TO 16Z. A PRE-
FRONTAL BAND OF SHOWERS WILL CROSS THE AREA BETWEEN 14 TO 17Z IN THE
WEST...EXITING EASTERN TERMINALS AOA 21Z. FCST SOUNDINGS AND
UPSTREAM TRENDS SUGGEST CIGS WILL LOWER TO MVFR WITHIN THE BAND OF
SHOWERS AND WILL REMAIN SUB-VFR UNTIL THE TRAILING SFC COLD FRONT
CROSSES THE AREA DURING THE EARLY EVENING...WITH CLEARING SPREADING
WEST TO EAST BETWEEN 00 TO 06Z.
OUTLOOK...VFR CONDITIONS SHOULD DOMINATE WEDNESDAY THROUGH EARLY
FRIDAY. A LOW PRESSURE SYSTEM TRACKING FROM THE GULF OF MEXICO
NORTHEASTWARD ALONG THE SOUTHEAST COAST WILL RESULT IN ADVERSE
AVIATION CONDITIONS LATE FRIDAY AND INTO THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...CBL
SHORT TERM...CBL
LONG TERM...KC
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
949 PM CST WED DEC 17 2014
.UPDATE...
ISSUED AT 949 PM CST WED DEC 17 2014
MAIN ISSUE LATE THIS EVENING WILL BE LIGHT SNOW/FLURRY CHANCES.
TEMPERATURES WILL BE A HASSLE AGAIN ALONG THE BORDER BETWEEN THE
LOW CLOUDS AND CLEAR SKIES OVER CENTRAL ND...BUT TREND SEEMS
REASONABLE SO NO BIG CHANGES HERE.
LATEST 00 UTC NAM AND 02 UTC RAP SHOW A COUPLE SHORTWAVE IMPULSES
ROTATING AROUND AN UPPER LOW OVER EASTERN MONTANA. THE LEAD WAVE
IS AIDING IN THE DEVELOPMENT OF A SMALL BAND OF SNOW SHOWERS
LIFTING NORTHWARD THROUGH SOUTHWEST INTO CENTRAL NORTH DAKOTA.
GROUND REPORTS ARE INDICATING A BRIEF PERIOD OF SNOW SHOWERS WITH
NO SIGNIFICANT ACCUMULATIONS. WITH THE SMALL BAND LIFTING QUICKLY
NORTH...OPTED TO KEEP THIS AS A CONTINUED MENTION OF FLURRIES AS
GETTING A HUNDREDTH OF AN INCH IS NOT LIKELY.
LATER TONIGHT AND INTO THURSDAY MORNING A STRONGER SHORTWAVE MOVES
WEST ALONG THE NORTH DAKOTA/SOUTH DAKOTA BORDER. ALTHOUGH RAP/NAM
QPF IS CURRENTLY NIL...THE RAP/HRRR ARE SHOWING SOME LIGHT RADAR
REFLECTIVITIES DEVELOPING OVER SOUTHWEST NORTH DAKOTA IN THE 07-12
UTC TIMEFRAME. THINKING AS WE GO THROUGH A FEW MORE ITERATIONS OF
THE RAP/HRRR...THIS MAY CONTINUE TO PROGRESS INTO THE SOUTH
CENTRAL DURING THE MORNING HOURS...AND POSSIBLY INCREASE GIVEN THE
STRENGTH OF THE SHORTWAVE. WITH A MOIST BOUNDARY LAYER AND
INCREASING SEEDER-FEEDER MECHANISM WITH INCREASING MID LEVEL
CLOUDS...HAVE EXTENDED FLURRIES THROUGH THURSDAY MORNING ACROSS
WESTERN AND CENTRAL NORTH DAKOTA. THINK MID SHIFT WILL HAVE THE
TIME TO RE-EVALUATE AND ADD A MENTION OF LIGHT SNOW FOR THE
MORNING HOURS IF NEEDED. ACCUMULATIONS WILL REMAIN LIGHT BUT THIS
SECOND WAVE LOOKS STRONG ENOUGH TO GIVE SOME OF US A LITTLE MORE
THAN JUST FLURRIES.
UPDATE ISSUED AT 551 PM CST WED DEC 17 2014
LOW STRATUS REMAINS ACROSS MUCH OF WESTERN AND CENTRAL NORTH
DAKOTA...AND WILL ONCE AGAIN BE A CONCERN FOR OVERNIGHT LOW
TEMPERATURES. DO EXPECT THE STRATUS TO BEGIN TO PROGRESS EASTWARD
LATER THIS EVENING AND OVERNIGHT...COVERING MOST IF NOT ALL OF THE
FORECAST AREA BY THURSDAY MORNING. SHORTWAVE LOCATED OVER EASTERN
MONTANA WILL PROVIDE ENOUGH LIFT FOR SOME LIGHT SNOW SHOWERS
MAINLY OVER THE SOUTHWEST. HOWEVER...WHEREVER WE HAVE THE STRATUS
WE CAN EXPECT A FEW FLURRIES. THIS IS CURRENTLY HANDLED WELL BY
PREVIOUS FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 352 PM CST WED DEC 17 2014
CURRENT SURFACE ANALYSIS PLACES HIGH OVER THE MIDWEST WITH TROUGH
MOVING TOWARDS THE SOUTHERN PLAINS. UPPER LEVEL ANALYSIS PLACES
RIDGE WORKING TOWARDS THE MIDWEST WITH COMPACT LOW LIFTING THROUGH
EASTERN MONTANA. BROAD LOW CLOUD COVER REMAINS OVER WESTERN NORTH
DAKOTA...THOUGH SOME HIGHER CLOUDS ARE ALSO MOVING THROUGH WITH
APPROACHING UPPER LOW.
FOR TONIGHT...CLOUD COVER OVER THE WEST WILL SPREAD TOWARDS THE
EAST THROUGH THE NIGHT. SOME LIGHT SNOW IS POSSIBLE WITH
APPROACHING UPPER LOW...MAINLY OVER THE SOUTHWEST...BUT WITH
LIMITED MOISTURE AVAILABLE ANY ACCUMULATIONS WILL BE QUITE LIGHT.
ELSEWHERE...FLURRIES REMAIN POSSIBLE.
ON THURSDAY...UPPER LOW CONTINUES TO SLOWLY WORK ITS WAY TO THE
EAST WHILE MILDER AIRMASS SLOWLY STARTS TO WORK ITS WAY INTO THE
AREA...BRINGING TEMPERATURES CLOSER TO AVERAGE. MODELS CONTINUE TO
KEEP MOISTURE IN PLACE OVER THE REGION KEEPING CLOUDY SKIES OVER
MOST LOCATIONS...WITH SOME CLEARING DEVELOPING OVER THE FAR WEST
IN THE AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 352 PM CST WED DEC 17 2014
QUIET THROUGH SATURDAY...ACTIVE END TO THE WEEKEND AND EARLY
HOLIDAY WEEK.
A WEAK SHORTWAVE TROUGH IS PROGGED TO SWING ACROSS SOUTHERN CANADA
SATURDAY/SUNDAY. THIS COULD SPARK SOME LIGHT SNOW SHOWERS ACROSS
NORTHERN NORTH DAKOTA. HOWEVER...IF ANY PRECIPITATION DOES DEVELOP
ONLY VERY LIGHT AMOUNTS SEEM POSSIBLE WITH THIS WAVE AS IT SHOULD BE
DISCONNECTED FROM THE MAIN PACIFIC MOISTURE FLOW THAT WILL ARRIVE
LATER SUNDAY INTO MONDAY.
SPEAKING OF SUNDAY INTO MONDAY...BROAD NORTHWEST FLOW AND A
LONGWAVE TROUGH IS EXPECTED TO DEVELOP ACROSS THE NORTHERN
PLAINS. THIS WILL LEAD TO A MUCH MORE ACTIVE WEATHER PERIOD. AT
THIS TIME IT APPEARS THE MOST SIGNIFICANT IMPACTS WITH THIS SYSTEM
WILL REMAIN JUST SOUTH AND EAST. HOWEVER...THE LATEST MODELS (12
UTC ECMWF/GFS) VARY GREATLY IN THE EVOLUTION OF THIS WAVE AND
PRECIPITATION PLACEMENT. THEREFORE...CLOSE ATTENTION WILL BE GIVEN
TO FOLLOWING MODEL RUNS AND THE EVOLUTION OF THIS SIGNIFICANT WAVE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 949 PM CST WED DEC 17 2014
IFR STRATUS CONTINUES AT KDIK WITH MVFR STRATUS AT KDIK. THIS WILL
LIKELY CONTINUE THROUGH THE FORECAST PERIOD. KBIS AND KMOT ARE ON
THE EDGE OF THE STRATUS...CURRENTLY CLEAR...BUT WILL LIKELY
EXPERIENCE MVFR STRATUS BEGINNING THIS EVENING AND CONTINUING
THROUGH THE 00 UTC FORECAST PERIOD. KJMS SHOULD REMAIN MAINLY
CLEAR THIS EVENING WITH MVFR STRATUS MOVING IN LATE TONIGHT...AND
THEN REMAINING THROUGH THE FORECAST PERIOD. A SOUTHERLY FLOW WILL
CONTINUE AT ALL TAF SITES. LOOKING A LATEST MESOSCALE MODELS WILL
PROBABLY ADD AT LEAST A PERIOD OF LIGHT SNOW ACROSS THE SOUTHERN
TAF SITES OF KDIK...KBIS...KJMS LATE TONIGHT INTO THURSDAY MORNING
WITH A SHORTWAVE MOVING WEST TO EAST ALONG THE SOUTH DAKOTA
BORDER. FOR NOW WILL LIKELY KEEP VSBYS ABOVE 5SM UNTIL WE SEE MORE
DEVELOPMENT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...JJS
LONG TERM...AJ
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1132 PM CST MON DEC 15 2014
.UPDATE...
ISSUED AT 940 PM CST MON DEC 15 2014
THERE IS SOME CLEARING WORKING INTO THE REGION FROM THE
NORTH...BUT ANOTHER AREA OF CLOUDS MOVING INTO THE REGION FROM THE
NORTHEAST. DID DECREASE SKY A BIT...BUT WILL CONTINUE THE MOSTLY
CLOUDY THINKING. WINDS WILL REMAIN ELEVATED...WHICH WILL KEEP
TEMPERATURES FROM BOTTOMING OUT WHETHER THERE ARE CLOUDS OR NO
CLOUDS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 330 PM CST MON DEC 15 2014
FORECAST CHALLENGE CONCERNS LINGERING PCPN CHANCES ACROSS THE SE
AND TEMPERATURES. MODELS OVERALL IN GOOD AGREEMENT AND WILL USE
BLEND FOR FORECAST.
DEFORMATION BAND OF PCPN FROM EXTREME SE ND INTO WEST CENTRAL MN
HAS SHOWN WEAKENING TREND AND HAS TRANSITION OVER TO ALL SNOW
WHICH LINES UP WELL WITH RUC SOUNDINGS. FORTUNATELY WEB CAMS
WITHIN HEAVIEST BAND INDICTED ONLY MINOR ACCUMULATIONS AND GOOD
VISIBILITY. AS SURFACE LOW PROPAGATES EAST THIS EVENING
DEFORMATION ZONE PCPN SHOULD FOLLOW WITH CONTINUED WEAKENING. WITH
EXPECTED TRENDS WILL EXPIRE CURRENT HEADLINES WITH FORECAST
ISSUANCE. GUSTY NORTH WINDS WHICH AT TIMES HAVE FLIRTED WITH
ADVISORY CRITERIA WILL CONTINUE TO DIMINISH THROUGH THE EVENING.
SOME BREAKS IN THE CLOUDS OCCURRING OVER MB LAKES REGION COULD WORK
INTO THE NORTHERN FA TONIGHT HOWEVER FOR THE MOST PART CLOUDS
SHOULD HOLD. CLOUDS AND WIND SHOULD OFF SET COLD ADVECTION WHICH
LEVELS OFF AFTER MIDNIGHT SO EXPECTING MINIMUMS A BIT ABOVE
SEASONAL AVERAGES.
HIGH PRESSURE PUSHES INTO THE REGION TUESDAY. COLUMN GRADUALLY
DRIES OUT HOWEVER W-NW FA MAY BE THE ONLY AREAS WITH ANY POTENTIAL
FOR SOLAR. THIS WILL LIMIT TEMPERATURE RECOVERY KEEPING MAXIMUM
TEMPERATURES BLO AVERAGE.
AS HIGH CONTINUES TO BUILD IN TOMORROW NIGHT DIMINISHING WINDS AND
CLEARING SHOULD ALLOW TEMPERATURES TO DROP INTO THE SINGLE DIGITS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 330 PM CST MON DEC 15 2014
HIGH PRESSURE WILL COVER FA WEDNESDAY AND DEGREE OF SOLAR WILL
IMPACT TEMPERATURES HOWEVER WITH COLD START TEMPERATURES WILL
STRUGGLE OUT OF THE TEENS.
COLUMN BEGINS TO RECOVER THURSDAY AND WITH SOLAR AND LACK OF SNOW
COVER TEMPERATURES SHOULD BE ABLE TO CLIMB BACK TO AVERAGE.
FOR THU NIGHT THROUGH MONDAY...KIND OF A MUDDLED MID LEVEL FLOW
PATTERN OVER THE NORTHERN PLAINS FOR FRI THRU SUNDAY. NOT MUCH UPPER
LEVEL ENERGY TO WORK WITH. AT THE SFC...BROAD HIGH PRESSURE REMAINS
ANCHORED OVER THE GREAT LAKES BUT STILL KEEPING SOME INFLUENCE OVER
THIS FA. THEREFORE ALTHOUGH MODELS KICK OUT SOME MINIMAL PCPN AT
TIMES WILL KEEP THIS PERIOD DRY. BY SUNDAY NIGHT INTO MONDAY WEST
COAST RIDGE STARTS TO BUILD UP A LITTLE RESULTING IN NORTHWEST FLOW
IN THIS AREA. SFC PATTERN STILL UNCERTAIN AND THEREFORE PCPN FIELDS
DIFFER QUITE A BIT BETWEEN MODELS. DESPITE THESE DIFFERENCES WILL
KEEP SOME CHANCES FOR LIGHT SNOW ON MONDAY WITH LOW PRESSURE IN THE
AREA. TEMPS LOOK TO STAY ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1132 PM CST MON DEC 15 2014
PREVIOUS THINKING STILL SEEMS TO BE WORKING OUT OK. THERE ARE SOME
CLEAR AREAS ACROSS THE REGION...BUT APPEAR TO BE SHORT-LIVED
ACCORDING TO SATELLITE IMAGERY. ANTICIPATE MAINLY MVFR CONDITIONS
THROUGH THE MORNING HOURS...WITH CLEARING AND/OR VFR CONDITIONS
BECOMING MORE LIKELY SOMETIME TUESDAY AFTERNOON OR EVENING. WINDS
WILL GRADUALLY DIMINISH THROUGH THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...VOELKER
LONG TERM...GODON/VOELKER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
849 PM EST WED DEC 17 2014
.SYNOPSIS...
WEAK HIGH PRESSURE WILL NOSE INTO THE REGION TONIGHT. HOWEVER
ABUNDANT LOW LEVEL MOISTURE WILL RESULT IN A CONTINUATION OF MAINLY
CLOUDY SKIES. A WEAK UPPER LEVEL DISTURBANCE COULD LEAD TO A FEW
FLURRIES THURSDAY AFTERNOON INTO THURSDAY NIGHT. HIGH PRESSURE WILL
BUILD BACK IN OFFERING DRY CONDITIONS AND NEAR SEASONABLE
TEMPERATURES FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AN ELONGATED AREA OF HIGH PRESSURE IS CURRENTLY CENTERED WEST OF
THE OHIO VALLEY. THIS HIGH WILL NUDGE INTO THE AREA BY
MORNING...WITH COOL WNW FLOW ON ITS NORTH SIDE ALLOWING FOR A
RELATIVE MIN IN SURFACE/925MB TEMPS THAT WILL STRETCH FROM CENTRAL
OHIO TO MINNESOTA. TEMPERATURES HAVE BEEN COOLING OFF A LITTLE
FASTER THAN THE PREVIOUS FORECAST INDICATED...SO A SLIGHT DOWNWARD
ADJUSTMENT WAS MADE TO THE MIN TEMPERATURE GRID.
AS THE PRESSURE GRADIENT WEAKENS...WINDS WILL BECOME LIGHTER AS
THE OVERNIGHT HOURS PROGRESS. HOWEVER...THE DIRECTION OF FLOW WILL
NOT BE FAVORABLE FOR THE ADVECTION OF THE MOISTURE CURRENTLY OVER
THE MIDDLE AND UPPER OHIO VALLEY. THE 00Z KILN SOUNDING INDICATED
SATURATION BETWEEN 925MB AND 875MB...CAPTURED WELL ON THE NAM12
AND RAP13...BUT VERY POORLY ON THE GFS AND ECMWF. THE EROSION OF
THE SOUTHERN/WESTERN EDGE OF THESE CLOUDS HAS SLOWED OR
STOPPED...AND THE FORECAST FOR THE OVERNIGHT WILL REMAIN VERY
CLOUDY. HOWEVER...SOME SLIGHT WARMING IS EXPECTED TO BEGIN AT
900MB AFTER 06Z...WHICH MAY BE ENOUGH TO LEAD TO SOME BREAKS IN
THE CLOUDS CLOSER TO MORNING.
PREVIOUS FORECAST >
ELONGATED MID LEVEL LOW OVER THE GREAT LAKES TO SHIFT OFF INTO NEW
ENGLAND. A FEW ISOLD LINGERING FLURRIES IN THE LOW LEVEL CAA WILL
COME TO AN END EARLY. MID LEVEL FLOW BECOMES BRIEFLY NW AHEAD OF AN
UPSTREAM S/W RIDGE. SFC HIGH PRESSURE TO NOSE INTO THE OHIO VALLEY
OVERNIGHT IN REGION OF H5 CONFLUENCE. 12Z ILN SOUNDING SHOWS LOW
LEVEL MOISTURE TRAPPED BELOW AN INVERSION AROUND 850 MB. GFS IS
AGGRESSIVE WITH CLEARING LOW LEVEL MOISTURE. NAM AND RAP SOLNS KEEP
CLOUDS OVERNIGHT. WILL ALLOW A FEW BREAKS OVER THE SOUTH/SOUTHWEST
BUT LEAN TOWARD THE NAM/RAP SOLN. TEMPERATURES WILL BE CLOSE TO
NORMAL WITH LOWS FROM THE MID 20S NORTH TO THE UPPER 20S SOUTH.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
MID LEVEL S/W TO RIPPLE QUICKLY EAST FROM THE CENTRAL PLAINS
THROUGH THE OHIO VALLEY THURSDAY. THIS WEAK SHORTWAVE IS DAMPENING
AND CROSSING OVER THE SFC RIDGE. FORCING IS VERY WEAK AND IN THE
MID LEVELS. A FLURRY OR SPRINKLE IS NOT OUT OF THE QUESTION FROM A
MID DECK. FLURRIES/SPRINKLES ALREADY IN THE FORECAST...SO WILL
CONTINUE. TEMPERATURES WILL BE BELOW NORMAL WITH HIGHS FROM THE
LOWER 30S NORTH TO THE MID/UPR 30S SOUTH.
IN WESTERLY MID LEVEL FLOW REGIME...SFC HIGH PRESSURE TO BUILD
ACRS THE GREAT LAKES/OHIO VALLEY THURSDAY NIGHT/FRIDAY. A FEW
FLURRIES WILL REMAIN POSSIBLE THURSDAY EVENING BUT WILL COME TO AN
END WITH THE PASSAGE OF THE S/W. AS THE HIGH BUILD NOSES IN
EXPECT SOME PARTIAL CLEARING THURSDAY NIGHT. LOWS EXPECTED TO
RANGE FROM THE MID 20S NORTH TO THE UPPER 20S SOUTH.
EXPECT TO SEE MORE SUNSHINE FRIDAY WITH AN INCREASE IN HIGH LEVEL
MOISTURE LATE IN THE DAY. FRIDAYS HIGHS FROM THE MID 30S NORTH TO
NEAR 40 SOUTH.
CLOUDS WILL THICKEN AND INCREASE FRIDAY NIGHT AS SYSTEM APPROACHES
FROM THE SOUTHWEST. WILL KEEP FCST DRY FRIDAY NIGHT AS CONSENSUS
DOES NOT BRING MOISTURE IN UNTIL SATURDAY. LOWS FRIDAY NIGHT TO
RANGE FROM THE UPPER 20S NORTH TO THE LOWER 30S FAR SOUTH.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
FOR SATURDAY...LOOKS LIKE WE COULD SEE SNOW CHANGING TO RAIN AS LOW
PRESSURE TRAVELS NEAR THE GULF COAST. THE LOW HAS TRENDED FARTHER TO
THE SOUTH SO CUT BACK ON POPS AND PRECIP AMOUNTS. HIGH PRESSURE AND
A COOL AIRMASS SHOULD ALLOW DRY WEATHER ON SUNDAY. LIGHT PRECIP WILL
BE POSSIBLE MONDAY EXTENDING FROM A TROUGH ALONG THE EAST COAST.
WE MAY BEGIN TO FEEL THE EFFECTS OF A POWERFUL LOW PRESSURE SYSTEM
ON TUESDAY. HAVE LESS THAN AVERAGE AMOUNT OF CONFIDENCE DUE TO MODEL
DIFFERENCES FROM RUN TO RUN. AT THIS POINT IT APPEARS THE LOW WILL
DEVELOP OVER THE SOUTHERN PLAINS ON TUESDAY...BEFORE LIFTING THROUGH
OHIO TO THE GREAT LAKES ON WEDNESDAY. THE LOW MAY FEATURE A VERY
TIGHT PRESSURE GRADIENT SURROUNDING ITS DEEP CENTER...PRODUCING
STRONG WINDS. COPIOUS MOISTURE FEEDING FROM THE TROPICS AND FROM THE
ATLANTIC OCEAN COULD ADVECT AROUND THE LOW. CURRENT TEMPERATURE
FORECAST ALLOWS RAIN TUESDAY INTO WEDNESDAY...CHANGING TO SNOW LATER
WEDNESDAY AS COLDER AIR WRAPS IN BEHIND THE LOW.
TEMPERATURES WILL BE RELATIVELY CLOSE TO NORMAL FOR THE MOST PART.
HIGHS ARE FORECAST TO BE IN THE MID AND UPPER 30S SATURDAY...THEN A
COUPLE DEGREES WARMER FOR SUNDAY AND MONDAY UNDER NEUTRAL TO WEAK
WARM ADVECTION. READINGS ON TUESDAY AND WEDNESDAY WILL BE DEPENDENT
ON THE POSITION OF THE ANTICIPATED STRONG LOW. WARM ADVECTION AHEAD
OF THE LOW COULD BRING HIGHS UP INTO THE MID 40S ON TUESDAY...OR
EVEN HIGHER IF THE WARMER MEX GUIDANCE VERIFIES. HIGHS COULD SLIP TO
AROUND 40 ON WEDNESDAY IN COLD ADVECTION BEHIND THE LOW.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
A PERSISTENT MVFR CLOUD DECK IS LIKELY TO REMAIN IN PLACE ACROSS
THE TAF SITES THROUGH THE ENTIRE FORECAST PERIOD. THESE CLOUDS ARE
GENERALLY LOCATED BETWEEN 1200 AND 2200 FEET ABOVE GROUND
LEVEL...AND LITTLE CHANGE IN HEIGHT IS EXPECTED...THOUGH A SLIGHT
LIFTING IS POSSIBLE TOMORROW. THIS CLOUD DECK HAS SHOWN SOME SIGNS
OF EROSION FROM THE SOUTH...BUT WHILE IT APPEARS POSSIBLE THAT
BREAKS IN THE OVERCAST COULD WORK INTO THE CINCINNATI AREA
OVERNIGHT...IT IS MORE LIKELY THAT THIS EROSION WILL SLOW OR STOP
IN THE NEXT FEW HOURS.
WNW WINDS OF AROUND 10 KNOTS WILL DIMINISH OVERNIGHT...AND REMAIN
UNDER 10 KNOTS TOMORROW. A FEW FLURRIES WILL BE POSSIBLE...MAINLY
AFTER 18Z...WITH NO EXPECTED IMPACTS TO AVIATION.
OUTLOOK...MVFR CEILINGS MAY CONTINUE INTO FRIDAY. MVFR CEILINGS AND
VISIBILITIES ARE POSSIBLE ON SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...AR
NEAR TERM...HATZOS/AR
SHORT TERM...AR
LONG TERM...CONIGLIO
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
346 PM EST TUE DEC 16 2014
.SYNOPSIS...
AS LOW PRESSURE MOVES NORTHEAST THROUGH THE GREAT LAKES...A FEW
SHOWERS WILL CONTINUE TO BE POSSIBLE INTO THE OVERNIGHT HOURS.
COOLER CONDITIONS ARE EXPECTED THROUGH THE REST OF THE WEEK...WITH
GENERALLY DRY CONDITIONS. A CHANCE OF RAIN AND SNOW IS IN THE
FORECAST FOR SATURDAY...AS WEAK LOW PRESSURE APPROACHES THE REGION
FROM THE SOUTH.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
WITHIN A LUMBERING MID-LEVEL TROUGH...CURRENTLY CENTERED OVER THE
GREAT LAKES...TWO DISTINCT VORTICITY MAXIMA ARE GRADUALLY
PROGRESSING AHEAD. THE FIRST OF THESE IS MOVING ENE THROUGH THE
SOUTHERN GREAT LAKES...WITH ITS INFLUENCE BEING FELT ACROSS THE
OHIO VALLEY...AND THROUGHOUT THE NWS ILN FORECAST AREA.
THE DIURNAL CYCLE TODAY HAS BEEN STUNTED FROM ITS RATHER WARM
STARTING POINT...AS COLD ADVECTION ON WESTERLY FLOW HAS ALREADY
BEGUN. THOUGH THERE IS NO DISTINCT DIRECTIONAL WIND SHIFT TO
HELP PICK OUT A CHANGE IN AIR MASS...THE REST OF THE DAY WILL
SIMPLY FEATURE A CONTINUED GRADUAL CLOCKWISE TURNING IN SURFACE
WINDS...ALONG WITH STEADY DROPS IN TEMPERATURES AND DEWPOINTS. A
STRONGER PUSH OF COLD ADVECTION JUST OFF THE SURFACE APPEARS
LIKELY TO BEGIN AFTER 06Z...WHICH SHOULD HELP LEAD TO STEEPER
LAPSE RATES NEAR THE GROUND...AND CONTINUED OCCASIONAL WIND GUSTS
TO AROUND 20 KNOTS. THIS WILL ALSO LIKELY KEEP RH VALUES RATHER
HIGH AT AROUND 925MB-875MB...AND LOW LEVEL CLOUDS ARE NOT EXPECTED
TO BREAK BEFORE MORNING.
RADAR HAS FINALLY STARTED TO SHOW A DIMINISHING TREND IN COVERAGE
FOR RAIN SHOWERS...AND THIS TREND IS EXPECTED TO CONTINUE. LIFT
ASSOCIATED WITH THE MID-LEVEL TROUGH IS ALREADY BEGINNING TO
DIMINISH...AS THE AXIS IS CLEARING THE CWA TO THE EAST.
HOWEVER...WITH THE THICK LOW-LEVEL MOISTURE IN PLACE...THERE
APPEARS TO BE A CHANCE FOR SOME VERY LIGHT RAIN OR DRIZZLE TO
CONTINUE INTO THE OVERNIGHT HOURS. HRRR SIMULATED REFLECTIVITY
HAS...ON SEVERAL RUNS...REFUSED TO GO COMPLETELY DRY DURING THIS
PERIOD. FORTUNATELY...IT APPEARS MOST LIKELY THAT ANY
RAIN/DRIZZLE/MIST POTENTIAL WILL BE DIMINISHING BEFORE
TEMPERATURES DROP BELOW FREEZING. THE 15Z SREF IS VERY LOW ON
PROBABILITIES FOR VISIBILITY REDUCTIONS...WHICH MAKES SENSE GIVEN
THE EXPECTED WINDS...BUT ALSO LENDS SUPPORT TOWARD WIDESPREAD MIST
OR DRIZZLE BEING UNLIKELY. THE MOST LIKELY SCENARIO WILL BE FOR A
FEW PATCHES OF LIGHT RAIN OR DRIZZLE THROUGH THE FIRST HALF OF THE
OVERNIGHT...POSSIBLY INTO THE EARLY MORNING IN CENTRAL OHIO.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS LOW PRESSURE MOVES NORTHEAST OF THE OHIO VALLEY...THE PRESSURE
GRADIENT WILL GRADUALLY RELAX ON WEDNESDAY...BUT CONTINUED COOL
WESTERLY FLOW WILL FORCE TEMPERATURES TO REMAIN BELOW AVERAGE.
ALTHOUGH DRY CONDITIONS ARE EXPECTED...THE BIGGEST FORECAST
CHALLENGE FOR WEDNESDAY WILL BE WITH SKY CONDITIONS. AS HAS BEEN
THE CASE SEVERAL TIMES ALREADY THIS COOL SEASON...THE NAM12
SOLUTION FOR LOW-LEVEL MOISTURE HAS REMAINED MUCH THICKER THAN
OTHER MODELS (GFS/GEM/ECMWF). KEEPING THE BOUNDARY LAYER WELL
MIXED BELOW 3000 FEET THROUGH THURSDAY MORNING...THE NAM12
MAINTAINS A THICK LAYER OF TRAPPED MOISTURE BELOW AN INVERSION.
DESPITE WHAT APPEARS TO BE A CONSENSUS FROM THE OTHER MODELS...THE
NAM12 HAS SHOWN SUCCESS IN THESE SCENARIOS THANKS TO ITS
RESOLUTION IN THE VERTICAL...AND IT CURRENTLY APPEARS TO BE
VERIFYING WELL OVER MISSOURI (WHERE OTHER MODELS ARE ALREADY
SUGGESTING CLEARER CONDITIONS THAN OBSERVED). SKY GRIDS HAVE THUS
BEEN INCREASED ON WEDNESDAY AND INTO WEDNESDAY NIGHT...ALLOWING
FOR SOME BREAKS IN THE EVENING.
AT 500MB ON WEDNESDAY NIGHT...A NARROW RIDGE WILL EXTEND FROM THE
SOUTHERN STATES NORTHWEST INTO THE MIDDLE MISSISSIPPI VALLEY. AS A
WEAK SHORTWAVE MOVES OUT OF THE FOUR CORNERS AREA AND RUNS INTO
THE RIDGE...IT WILL WEAKEN FURTHER...EVENTUALLY WASHING OUT OVER
THE OHIO VALLEY ON THURSDAY. BEFORE THE SYSTEM DISSIPATES...IT
APPEARS THAT SOME WEAK ISENTROPIC LIFT WILL ALLOW FOR AN INCREASE
IN CLOUDS ON THURSDAY...MOVING FROM SOUTHWEST TO NORTHEAST ACROSS
THE OHIO VALLEY. A SLIGHT CHANCE OF PRECIPITATION (MAINLY SNOW)
WAS ALSO INCLUDED...AS MOST LOCATIONS ARE LIKELY TO REMAIN
DRY...BUT SOME LIGHT PRECIPITATION MAY MAKE IT DOWN. MOST OF THE
CLOUDS AND FORCING SHOULD REMAIN ABOVE 5000 FEET...WITH AN
EXTREMELY WEAK SURFACE PRESSURE PATTERN PROVIDING NO SUPPORT.
COLD ADVECTION ON THURSDAY WILL BE MUCH WEAKER WITH THE LIGHTER
FLOW...BUT WITH A RELATIVELY SMALL DIURNAL TEMPERATURE COMPONENT
EXPECTED...TEMPERATURES ON THURSDAY ARE EXPECTED TO REMAIN FAIRLY
SIMILAR TO VALUES ON WEDNESDAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
HIGH PRESSURE AND DRY CONDITIONS WILL START OUT THE LONG TERM
PERIOD. THE NEXT SYSTEM WILL BEGIN TO APPROACH THE AREA LATE FRIDAY
NIGHT AND INTO THE DAY ON SATURDAY BEFORE TAPERING OFF SATURDAY
NIGHT. PRECIPITATION WILL GENERALLY BE IN THE FORM OF LIGHT SNOW
ACROSS THE NW HALF OF THE FA. PRECIPITATION IS EXPECTED TO START
OFF AS SNOW ACROSS THE SE HALF OF THE FA HOWEVER SOME RAIN IS
EXPECTED TO MIX IN DURING THE DAY BEFORE TRANSITIONING BACK TO LIGHT
SNOW.
HIGH PRESSURE WILL THEN WORK BACK INTO THE AREA FOR SUNDAY AND
MONDAY. THE NEXT SYSTEM WILL BEGIN TO WORK INTO THE AREA FOR
TUESDAY. MODELS WERE IN SOMEWHAT DECENT AGREEMENT WITH THIS FEATURE
HOWEVER THE 12Z ECMWF SOLUTION IS NOW SLOWER AND MORE ROBUST. DID
NOT WANT TO JUMP ON THIS NEW SOLUTION QUITE YET AND WENT WITH MORE
OF A MODEL BLEND FOR TUESDAY. A MIX OF RAIN AND SNOW ARE EXPECTED
HOWEVER AS COLDER AIR BEGINS TO MOVE INTO THE AREA PRECIPITATION
LOOKS TO CHANGE OVER TO ALL SNOW SHOWERS DURING THE TUESDAY NIGHT
INTO WEDNESDAY TIME PERIOD.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
SURFACE LOW PRESSURE NEAR WESTERN LAKE ERIE EARLY THIS AFTERNOON
WILL LIFT SLOWLY EAST/NORTHEAST TO SE CANADA THROUGH THE TAF
PERIOD. ONE MORE PIECE OF UPPER LEVEL ENERGY IS EXPECTED TO ROTATE
EAST THROUGH THE TAF SITES THIS AFTERNOON. THIS WILL BRING A ROUND
OF VFR/MVFR SHOWERS ALONG WITH MVFR CEILINGS. FOR LATE THIS
AFTERNOON INTO THE EARLY MORNING HOURS...CEILINGS ARE EXPECTED TO
DROP INTO THE IFR CATEGORY FOR A PERIOD OF TIME AS CONSIDERABLE
MOISTURE IN THE LOW LEVELS CONTINUES TO WRAP AROUND DEPARTING LOW
PRESSURE. SOME MODELS SUGGEST THAT CEILING MAY LIFT ABOVE 1000
FEET BETWEEN 06Z AND 08Z BUT STILL REMAIN BELOW 2000 FEET.
ON WEDNESDAY...ANOTHER UPPER LEVEL DISTURBANCE IS EXPECTED TO
ROTATE EAST ACROSS THE GREAT LAKES. SURFACE HIGH PRESSURE TO OUR
NORTHWEST WILL BE SLOW TO BUILD IN. SOME MODELS SUGGEST THAT IT
MAY TAKE AWHILE FOR LOW LEVEL CLOUDS TO ERODE AND/OR SHIFT OFF TO
THE NORTHEAST...SO HAVE LIFTED CEILINGS ABOVE 2000 FEET AT THE 30
HOUR KCVG TAF BY 18Z BUT KEPT CEILINGS BROKEN.
OUTLOOK...MVFR CEILINGS MAY LINGER INTO WEDNESDAY EVENING. MVFR
CEILINGS AND VISIBILITIES POSSIBLE FRIDAY NIGHT INTO SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...NOVAK
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
743 AM EST TUE DEC 16 2014
.SYNOPSIS...
OCCASIONAL SHOWERS ARE EXPECTED TODAY AS A LOW PRESSURE SYSTEM
LIFTS NORTHEAST INTO THE GREAT LAKES REGION. A COLDER AIRMASS
WILL THEN SETTLE INTO THE REGION WITH SEASONABLY COOLER
TEMPERATURES EXPECTED THROUGH THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A FAIRLY SOLID LINE OF SHOWERS IS CURRENTLY MOVING THROUGH
SOUTHEAST INDIANA AND INTO FAR WESTERN OHIO. THESE SHOWERS ARE
WITHIN A LOW LEVEL CONVERGENT BOUNDARY ASSOCIATED WITH AN
APPROACHING FRONTAL BOUNDARY. VERY MARGINAL INSTABILITY IS WORKING
NORTHEAST INTO SOUTHERN PORTIONS OF OUR FA AND THIS HAS ALLOWED
FOR A FEW EMBEDDED THUNDERSTORMS TO DEVELOP. INTERESTINGLY...THE
SHERB PARAMETER OFF BOTH THE RAP AND NAM SEEMS TO BE PICKING UP
ON SOME OF THIS BETTER FORCING/INSTABILITY...WITH A NARROW AXIS OF
HIGHER VALUES MOVING THROUGH THE TRI STATE REGION OVER THE NEXT
FEW HOURS. AS A RESULT...WILL INCLUDE AN ISOLATED THUNDERSTORM THROUGH
DAYBREAK ACROSS SOUTHWEST PORTIONS OF OUR FA. THE BULK OF THE PCPN
SHOULD CONTINUE TO PIVOT UP ACROSS NORTHERN PORTIONS OF OUR FA
THROUGH LATE MORNING. EXPECT PCPN TO THEN BECOME MORE SCATTERED AS
WE HEAD INTO THIS AFTERNOON AND GET INTO SOME WRAP AROUND
MOISTURE. EXPECT EARLY HIGHS TODAY WITH TEMPERATURES THEN LEVELING
OFF OR EVEN BEGINNING TO FALL AS WE START TO GET INTO SOME
DEVELOPING LOW LEVEL CAA THROUGH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
THE LOW PRESSURE WILL CONTINUE TO LIFT OFF TO THE NORTHEAST TONIGHT
WITH PCPN TAPERING OFF TO JUST A FEW SHOWERS THROUGH THIS EVENING.
IT STILL LOOKS LIKE THE DEEPER MOISTURE WILL BE EXITING OUR AREA
BEFORE THE BOUNDARY LAYER COOLS OFF ENOUGH FOR MUCH IN THE WAY OF
SNOW. AS A RESULT..WILL JUST ALLOW FOR A BRIEF MIX ACROSS THE
NORTH LATER THIS EVENING AS THE PCPN TAPERS OFF. HIGH PRESSURE
WILL THEN BUILD INTO THE REGION FOR WEDNESDAY INTO THURSDAY.
TEMPERATURES WILL BE SEASONABLY COOL WITH HIGHS ONLY IN THE 30S
WEDNESDAY AND THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
FORECAST PERIOD BEGINS WITH THE MODELS IN AGREEMENT IN PLACING A
STRUNG OUT HIGH PRESSURE SYSTEM FROM THE NORTHERN PLAINS DOWN INTO
THE UPPER OHIO VALLEY. THE HIGH WILL DRIFT SLOWLY EASTWARD PROVIDING
DRY CONDITIONS THROUGH FRIDAY.
THE GFS CONTINUES WITH ITS STRUGGLES IN DEALING WITH ENERGY SWINGING
OUT OF THE LOWER MS VALLEY FRIDAY. AFTER WINDING UP A LOW AND
LIFTING IT N INTO THE REGION WITH YESTERDAYS RUN...THE GFS NOW TAKES
A QUICK MOVING SHEARED OUT H5 VORT INTO THE TN VALLEY AND SPREADS
PCPN INTO SOUTHERN PORTIONS OF THE REGION MUCH QUICKER THAN THE
OTHER MODELS FRIDAY NIGHT. THE ECMWF HAS BEEN CONSISTENT WITH ITS
SOLUTION OF A TAKING A SLOWER A MORE DEFINED SFC LOW INTO THE
CAROLINAS FRIDAY NIGHT INTO SATURDAY. WILL CONTINUE TO FOLLOW THE
ECMWF SOLUTION AS IT IS BACKED BY THE CONSENSUS OF THE MODELS.
SO BROUGHT SOME SLIGHT CHANCE/CHANCE POPS INTO SOUTHERN SECTIONS
LATE FRIDAY NIGHT. SINCE WE ARE ON THE EXTREME NRN EDGE..MOST OF THE
PCPN SHOULD FALL AS SNOW...BUT CANT RULE OUT SOME SLEET OR RAIN
MIXING IN. AS THE SFC PATTERN TRANSITIONS TO THE EAST COAST ON
SATURDAY...A H5 S/W SWINGING THRU WILL PROVIDE LIFT AND WILL PULL
PCPN ACROSS THE AREA. A CHANCE OF LIGHT SNOW WILL TRANSITION TO A
RAIN/SNOW MIX DURING THE DAY ON SATURDAY. A CHANCE OF SNOW WILL
LINGER INTO SATURDAY NIGHT AND EARLY SUNDAY.
HIGH PRESSURE WILL BUILD IN FOR THE LAST FEW DAYS OF THE FORECAST
PERIOD.
HIGHS THRU THE PERIOD WILL BE NEAR TO SLIGHTLY BELOW NORMAL. THEY
SHOULD RANGE IN THE 30S FOR THURSDAY. SOUTHERN LOCATIONS MIGHT MAKE
IT INTO THE 40S FRIDAY WHILE THE NORTH REMAINS IN THE 30S. COOLER
AIR WILL WORK BACK IN SATURDAY THRU MONDAY KEEPING HIGHS IN THE 30S.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
AN OCCLUDED FRONT IS PUSHING ACROSS THE REGION THIS MORNING WITH
AN ASSOCIATED BAND OF SHOWERS AND ISOLATED TSTMS VCNTY KLUK 12Z
AND KILN 13Z. THE BACK EDGE OF THIS BAND OF SHOWERS EXTENDS FROM
KCVG TO KDAY AT 12Z AND SHOULD CLEAR ALL THE TERMINALS BY 14Z AS
IT CONTINUE TO MOVE NE. UNSTABLE AIR BEHIND THE FRONT WILL ALLOW
FOR SOME LIGHT VCSH TILL AROUND NOON. A FEW LIGHT SHOWERS ARE
POSSIBLE THROUGH THE REMAINDER OF THE AFTERNOON BUT ARE EXPECTED
TO BE INCONSEQUENTIAL AND HAVE BEEN LEFT OUT OF THE FORECAST.
CYCLONIC FLOW WILL CONTINUE OVER THE AREA THROUGH THE FORECAST
PERIOD MAINTAINING MVFR CIGS.
SFC WINDS ARE EXPECTED TO VEER TO THE WSW AND GUST TO NEAR 25KT BY
LATE MORNING AND CONTINUE WELL INTO THE EVENING.
OUTLOOK...MVFR CEILINGS WILL CONTINUE INTO WEDNESDAY MORNING. MVFR
CEILINGS AND VISIBILITIES POSSIBLE FRIDAY NIGHT INTO SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...SITES
AVIATION...HAYDU
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
405 AM EST TUE DEC 16 2014
.SYNOPSIS...
OCCASIONAL SHOWERS ARE EXPECTED TODAY AS A LOW PRESSURE SYSTEM
LIFTS NORTHEAST INTO THE GREAT LAKES REGION. A COLDER AIRMASS
WILL THEN SETTLE INTO THE REGION WITH SEASONABLY COOLER
TEMPERATURES EXPECTED THROUGH THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A FAIRLY SOLID LINE OF SHOWERS IS CURRENTLY MOVING THROUGH
SOUTHEAST INDIANA AND INTO FAR WESTERN OHIO. THESE SHOWERS ARE
WITHIN A LOW LEVEL CONVERGENT BOUNDARY ASSOCIATED WITH AN
APPROACHING FRONTAL BOUNDARY. VERY MARGINAL INSTABILITY IS WORKING
NORTHEAST INTO SOUTHERN PORTIONS OF OUR FA AND THIS HAS ALLOWED
FOR A FEW EMBEDDED THUNDERSTORMS TO DEVELOP. INTERESTINGLY...THE
SHERB PARAMETER OFF BOTH THE RAP AND NAM SEEMS TO BE PICKING UP
ON SOME OF THIS BETTER FORCING/INSTABILITY...WITH A NARROW AXIS OF
HIGHER VALUES MOVING THROUGH THE TRI STATE REGION OVER THE NEXT
FEW HOURS. AS A RESULT...WILL INCLUDE AN ISOLATED THUNDERSTORM THROUGH
DAYBREAK ACROSS SOUTHWEST PORTIONS OF OUR FA. THE BULK OF THE PCPN
SHOULD CONTINUE TO PIVOT UP ACROSS NORTHERN PORTIONS OF OUR FA
THROUGH LATE MORNING. EXPECT PCPN TO THEN BECOME MORE SCATTERED AS
WE HEAD INTO THIS AFTERNOON AND GET INTO SOME WRAP AROUND
MOISTURE. EXPECT EARLY HIGHS TODAY WITH TEMPERATURES THEN LEVELING
OFF OR EVEN BEGINNING TO FALL AS WE START TO GET INTO SOME
DEVELOPING LOW LEVEL CAA THROUGH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
THE LOW PRESSURE WILL CONTINUE TO LIFT OFF TO THE NORTHEAST TONIGHT
WITH PCPN TAPERING OFF TO JUST A FEW SHOWERS THROUGH THIS EVENING.
IT STILL LOOKS LIKE THE DEEPER MOISTURE WILL BE EXITING OUR AREA
BEFORE THE BOUNDARY LAYER COOLS OFF ENOUGH FOR MUCH IN THE WAY OF
SNOW. AS A RESULT..WILL JUST ALLOW FOR A BRIEF MIX ACROSS THE
NORTH LATER THIS EVENING AS THE PCPN TAPERS OFF. HIGH PRESSURE
WILL THEN BUILD INTO THE REGION FOR WEDNESDAY INTO THURSDAY.
TEMPERATURES WILL BE SEASONABLY COOL WITH HIGHS ONLY IN THE 30S
WEDNESDAY AND THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
FORECAST PERIOD BEGINS WITH THE MODELS IN AGREEMENT IN PLACING A
STRUNG OUT HIGH PRESSURE SYSTEM FROM THE NORTHERN PLAINS DOWN INTO
THE UPPER OHIO VALLEY. THE HIGH WILL DRIFT SLOWLY EASTWARD PROVIDING
DRY CONDITIONS THROUGH FRIDAY.
THE GFS CONTINUES WITH ITS STRUGGLES IN DEALING WITH ENERGY SWINGING
OUT OF THE LOWER MS VALLEY FRIDAY. AFTER WINDING UP A LOW AND
LIFTING IT N INTO THE REGION WITH YESTERDAYS RUN...THE GFS NOW TAKES
A QUICK MOVING SHEARED OUT H5 VORT INTO THE TN VALLEY AND SPREADS
PCPN INTO SOUTHERN PORTIONS OF THE REGION MUCH QUICKER THAN THE
OTHER MODELS FRIDAY NIGHT. THE ECMWF HAS BEEN CONSISTENT WITH ITS
SOLUTION OF A TAKING A SLOWER A MORE DEFINED SFC LOW INTO THE
CAROLINAS FRIDAY NIGHT INTO SATURDAY. WILL CONTINUE TO FOLLOW THE
ECMWF SOLUTION AS IT IS BACKED BY THE CONSENSUS OF THE MODELS.
SO BROUGHT SOME SLIGHT CHANCE/CHANCE POPS INTO SOUTHERN SECTIONS
LATE FRIDAY NIGHT. SINCE WE ARE ON THE EXTREME NRN EDGE..MOST OF THE
PCPN SHOULD FALL AS SNOW...BUT CANT RULE OUT SOME SLEET OR RAIN
MIXING IN. AS THE SFC PATTERN TRANSITIONS TO THE EAST COAST ON
SATURDAY...A H5 S/W SWINGING THRU WILL PROVIDE LIFT AND WILL PULL
PCPN ACROSS THE AREA. A CHANCE OF LIGHT SNOW WILL TRANSITION TO A
RAIN/SNOW MIX DURING THE DAY ON SATURDAY. A CHANCE OF SNOW WILL
LINGER INTO SATURDAY NIGHT AND EARLY SUNDAY.
HIGH PRESSURE WILL BUILD IN FOR THE LAST FEW DAYS OF THE FORECAST
PERIOD.
HIGHS THRU THE PERIOD WILL BE NEAR TO SLIGHTLY BELOW NORMAL. SOUTHERN
LOCATIONS MIGHT MAKE IT INTO THE 40S FRIDAY WHILE THE NORTH
REMAINS IN THE 30S. COOLER AIR WILL WORK BACK IN SATURDAY THRU
MONDAY KEEPING HIGHS IN THE 30S.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
AN OCCLUDED FRONT WILL PUSH ACROSS THE REGION BY MID-MORNING.
THERE WILL BE SCATTERED LIGHT SHOWERS BOTH AHEAD AND ALONG THIS
BOUNDARY. DO NOT EXPECT ANY PRECIPITATION TO CAUSE VISIBILITY
RESTRICTIONS. HOWEVER CEILINGS WILL LOWER TO MVFR AND EVENTUALLY
DROP BELOW 2000 FT. WINDS WILL SHIFT TO SOUTH WITH THE FRONTAL
PASSAGE. THE WINDS WILL VEER TO SOUTHWEST AND STRENGTHEN SOME
AFTER 15Z. MVFR CEILINGS WILL CONTINUE TO PREVAIL. SOME SHOWERS
WILL REMAIN POSSIBLE. BY NOON ANY LINGER SHOWERS WILL BE
INCONSEQUENTIAL AND HAVE BEEN LEFT OUT OF THE FORECAST. NOT MUCH
CHANGE THROUGH THE REMAINDER OF THE FORECAST PERIOD AS MVFR CONDS
WILL PREVAIL AND WINDS WILL REMAIN GUSTY WELL INTO THE NIGHTTIME
HOURS.
OUTLOOK...MVFR CEILINGS WILL CONTINUE INTO WEDNESDAY. MVFR
CEILINGS AND VISIBILITIES POSSIBLE FRIDAY NIGHT INTO SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...SITES
AVIATION...HAYDU
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
109 AM EST TUE DEC 16 2014
.SYNOPSIS...
OCCLUDED LOW PRESSURE WILL TRAVEL FROM THE MISSISSIPPI VALLEY TO
THE GREAT LAKES TONIGHT THROUGH TUESDAY. SHOWERS WILL DEVELOP
IN THE MOIST FLOW CIRCULATING AROUND THE LOW. PRECIPITATION WILL
END BY WEDNESDAY AS THE LOW TRAVELS EAST...WITH COLDER
TEMPERATURES ARRIVING ON A BRISK WESTERLY FLOW BEHIND THE LOW.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SHOWERS HAVE FINALLY DEVELOPED INTO A BAND AS THEY ENTERED THE
FORECAST AREA. EXPECT THIS TO CONTINUE TO SWEEP EAST NORTHEAST
OVERNIGHT. RECENT HRRR AND RAP RUNS HAVE BEEN SUGGESTING THAT
ANOTHER AREA OF SHOWERS WILL DEVELOP AFTER 06Z AND MOVE NORTHEAST.
HAVE ADJUSTED POPS ACCORDINGLY. RAINFALL AMOUNTS WILL MOSTLY
REMAIN ON THE LIGHT SIDE. CLOUDS AND AND LACK OF TEMPERATURE
ADVECTION WILL RESULT IN LITTLE MOVEMENT TO TEMPERATURES THROUGH
THE NIGHT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
LOW PRESSURE WILL BE PUSHING THROUGH THE GREAT LAKES ON TUESDAY. A
CHANCE OF SHOWERS WILL PERSIST IN THE RELATIVELY MOIST CYCLONIC
FLOW BEHIND THE LOW.
AS THE BRISK WESTERLY FLOW CONTINUES IN THE WAKE OF THE LOW NOW
OVER SOUTHEAST CANADA...DRIER AIR AT THE LEADING EDGE OF HIGH
PRESSURE WILL FILTER IN BY WEDNESDAY...BRINGING AN END TO
PRECIPITATION.
HIGH TEMPERATURES WILL STAY CLOSE TO 50 TUESDAY IN THE MILD REGIME
SURROUNDING THE DEPARTING LOW. COLDER HIGHS AROUND 40 ARE IN STORE
FOR WEDNESDAY AS COLD ADVECTION RESULTS IN A RETURN TO NEAR NORMAL
TEMPERATURES.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
FORECAST PERIOD BEGINS WITH THE MODELS IN AGREEMENT IN PLACING A
STRUNG OUT HIGH PRESSURE SYSTEM FROM THE NORTHERN PLAINS DOWN INTO
THE UPPER OHIO VALLEY. THE HIGH WILL DRIFT SLOWLY EASTWARD PROVIDING
DRY CONDITIONS THROUGH FRIDAY.
THE GFS CONTINUES WITH ITS STRUGGLES IN DEALING WITH ENERGY SWINGING
OUT OF THE LOWER MS VALLEY FRIDAY. AFTER WINDING UP A LOW AND
LIFTING IT N INTO THE REGION WITH YESTERDAYS RUN...THE GFS NOW TAKES
A QUICK MOVING SHEARED OUT H5 VORT INTO THE TN VALLEY AND SPREADS
PCPN INTO SOUTHERN PORTIONS OF THE REGION MUCH QUICKER THAN THE
OTHER MODELS FRIDAY NIGHT. THE ECMWF HAS BEEN CONSISTENT WITH ITS
SOLUTION OF A TAKING A SLOWER A MORE DEFINED SFC LOW INTO THE
CAROLINAS FRIDAY NIGHT INTO SATURDAY. WILL CONTINUE TO FOLLOW THE
ECMWF SOLUTION AS IT IS BACKED BY THE CONSENSUS OF THE MODELS.
SO BROUGHT SOME SLIGHT CHANCE/CHANCE POPS INTO SOUTHERN SECTIONS
LATE FRIDAY NIGHT. SINCE WE ARE ON THE EXTREME NRN EDGE..MOST OF THE
PCPN SHOULD FALL AS SNOW...BUT CANT RULE OUT SOME SLEET OR RAIN
MIXING IN. AS THE SFC PATTERN TRANSITIONS TO THE EAST COAST ON
SATURDAY...A H5 S/W SWINGING THRU WILL PROVIDE LIFT AND WILL PULL
PCPN ACROSS THE AREA. A CHANCE OF LIGHT SNOW WILL TRANSITION TO A
RAIN/SNOW MIX DURING THE DAY ON SATURDAY. A CHANCE OF SNOW WILL
LINGER INTO SATURDAY NIGHT AND EARLY SUNDAY.
HIGH PRESSURE WILL BUILD IN FOR THE LAST FEW DAYS OF THE FORECAST
PERIOD.
HIGHS THRU THE PERIOD WILL BE NEAR TO SLIGHTLY BELOW NORMAL. THEY
SHOULD RANGE IN THE 30S FOR THURSDAY. SOUTHERN LOCATIONS MIGHT MAKE
IT INTO THE 40S FRIDAY WHILE THE NORTH REMAINS IN THE 30S. COOLER
AIR WILL WORK BACK IN SATURDAY THRU MONDAY KEEPING HIGHS IN THE 30S.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AN OCCLUDED FRONT WILL PUSH ACROSS THE REGION BY MID-MORNING.
THERE WILL BE SCATTERED LIGHT SHOWERS BOTH AHEAD AND ALONG THIS
BOUNDARY. DO NOT EXPECT ANY PRECIPITATION TO CAUSE VISIBILITY
RESTRICTIONS. HOWEVER CEILINGS WILL LOWER TO MVFR AND EVENTUALLY
DROP BELOW 2000 FT. WINDS WILL SHIFT TO SOUTH WITH THE FRONTAL
PASSAGE. THE WINDS WILL VEER TO SOUTHWEST AND STRENGTHEN SOME
AFTER 15Z. MVFR CEILINGS WILL CONTINUE TO PREVAIL. SOME SHOWERS
WILL REMAIN POSSIBLE. BY NOON ANY LINGER SHOWERS WILL BE
INCONSEQUENTIAL AND HAVE BEEN LEFT OUT OF THE FORECAST. NOT MUCH
CHANGE THROUGH THE REMAINDER OF THE FORECAST PERIOD AS MVFR CONDS
WILL PREVAIL AND WINDS WILL REMAIN GUSTY WELL INTO THE NIGHTTIME
HOURS.
OUTLOOK...MVFR CEILINGS WILL CONTINUE INTO WEDNESDAY. MVFR
CEILINGS AND VISIBILITIES POSSIBLE FRIDAY NIGHT INTO SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...
SHORT TERM...CONIGLIO
LONG TERM...SITES
AVIATION...HAYDU
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1157 PM EST MON DEC 15 2014
.SYNOPSIS...
LOW PRESSURE IN THE CENTRAL PLAINS WILL MOVE ACROSS THE CENTRAL
GREAT LAKES REGION TUESDAY DRAGGING A FRONTAL SYSTEM ACROSS THE
REGION. HIGH PRESSURE WILL BUILD IN LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SPEEDED UP TIMING OF RAIN SLIGHTLY FOR THE 930 UPDATE..
ORIGINAL DISCUSSION...
MODELS SHOW LOW PRESSURE ACROSS IOWA AND NRN MO LATE THIS
AFTERNOON WITH THE AXIS OF AN UPPER RIDGE JUST TO OUR EAST.
SUBSIDENCE AHEAD OF THE APPROACHING LOW HAS ALLOWED THE CLOUDS TO
BREAK THROUGH THE AFTERNOON ACROSS MUCH OF THE AREA. THE PROGRESS
OF THE LOW HOWEVER WILL TAKE IT TO SRN LAKE MI OVERNIGHT WITH A
COLD FRONT/OCCLUDED FRONT SOUTHEAST INTO WESTERN OHIO BY 12Z.
PRECIP TO OUR WEST AHEAD OF THE SYSTEM SO FAR IS NOT TOO
IMPRESSIVE HOWEVER FOLLOWING THE HRRR NAM AND SREF...MODELS BRING
IN A SWATH OF RAIN THROUGH THE EVENING EXPANDING IT THROUGH THE
EVENING AND OVERNIGHT AS THE UPPER SYSTEM AND ASSOCIATED DYNAMICS
OVERSPREAD THE REGION. WILL HAVE CAT POPS FOR MOST...MOVING FROM
WEST TO EAST THROUGH THE NIGHT. LOWS GENERALLY UPPER 30S TO LOWER
40S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
TUESDAY BEGINS WITH LOW PRESSURE OVER SRN LAKE MI WITH A
COLD/OCCLUDED FRONT NEAR A KTOL-KFDY-KCMH. EXPECTING RAIN TO BE
OCCURRING ACROSS NWRN PA FROM THE INITIAL SURGE FINALLY REACHING
THE AREA JUST BEFORE DAWN. CENTRAL COUNTIES...PRECIP COULD BEGIN
SPOTTY WITH A MARGINAL DRY SLOT ACROSS MUCH OF THE AREA. MOISTURE
WITH THE UPPER SYSTEM WILL BE MOVING INTO THE WEST. THE UPPER LOW
WILL MOVE ENE ACROSS THE CENTRAL LAKES DURING THE DAY WITH DEEP
MOISTURE AND WEAK COLD ADVECTION SPREADING ACROSS THE CWA. WILL
HAVE LIKELY POPS ACROSS THE AREA DURING THE DAY FOR RAIN. THE
UPPER TROUGH AXIS SHIFTS EAST THROUGH THE EVENING. AM THINKING
WESTERN COUNTIES COULD POSSIBLY SEE A FEW SHOWERS THROUGH THE
EVENING BUT WITH FORCING GONE TAPERED POPS WEST THROUGH THE
OVERNIGHT TO SLIGHT CHANCE. WINDS TURN OFF THE LAKE FOR THE SNOW
BELT TUESDAY NIGHT BUT 850MB TEMPS NOT LOW ENOUGH FOR LAKE
INSTABILITY. WILL HOLD ONTO CHANCE POPS GIVEN MOISTURE SOURCE BUT
NOT EXPECTING A LOT GIVEN FORCING EAST OF THE AREA. WEDNESDAY
HOWEVER...850MB TEMPS BEGIN TO DROP TO -6 TO -8C DURING THE DAY.
STILL...LES NOT INDICATED HOWEVER STILL THINK SNOW SHOWERS WILL
DEVELOP. WILL HAVE CHANCE POPS GOING TO LIKELY IN THE AFTERNOON.
WEDNESDAY NIGHT 850MB TEMPS DROP FURTHER TO -12C WITH ANOTHER
UPPER TROF CROSSING THE LAKE GIVEN THE ADDED DYNAMICS AM MORE
CONFIDENT IN SNOW SHOWERS ACROSS THE EAST LAKESHORE/SNOW
BELT...LASTING INTO EARLY THURSDAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
HIGH PRESSURE IS EXPECTED TO BE SHIFTING INTO THE EASTERN LAKES FRI
WHICH SHOULD BRING THE LAKE EFFECT SHSN TO AN END BY FRI NIGHT.
LITTLE ADDITIONAL ACCUMULATION IS LIKELY ON FRI.
THE MODELS START TO DIFFER INTO SAT ON WHERE AN UPPER LOW TRACKS
THUS AFFECTING THE TRACK OF A SURFACE LOW. THE GFS IS NOW SHOWING A
MUCH WEAKER SURFACE LOW WITH A BROAD AREA OF MOISTURE WORKING UP
THROUGH THE OH VALLEY MOSTLY FORCED BY THE UPPER TROUGH. THE ECMWF
HAS A MUCH STRONGER SOUTHERN STREAM UPPER LOW AND ASSOCIATED SURFACE
LOW. IN EITHER CASE THERE SHOULD BE PRECIP SPREADING NE ACROSS THE
CWA LATE SAT OR SAT NIGHT AND SHIFTING INTO MAINLY THE EAST SUN.
TEMPS ON THE EDGE FOR EITHER RAIN OR SNOW ON SAT BUT A LITTLE COLDER
AIR MOVING IN FOR SAT NIGHT AND SUN SHOULD LEAD TO MOSTLY SNOW THEN.
TEMPS DON`T LOOK TO GET COLD ENOUGH FOR LAKE EFFECT OF ANY
SIGNIFICANCE LATER SUN THEN HIGH PRESSURE IS EXPECTED TO MOVE OVER
THE AREA SUN NIGHT TO PROVIDE DRY CONDITIONS. ANOTHER UPPER TROUGH
IS PROGGED TO BE MOVING EAST INTO THE LAKE ERIE AREA BY LATE MON SO
THE DRY CONDITIONS MAY NOT LAST THRU THE DAY.
TEMPS DON`T APPEAR TO SHOW A LOT OF CHANGE SUN THRU MON.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
SOME LOW CLOUDS THAT WERE OVER NE OH AND NW PA HAVE JUST ABOUT
DECREASED. THE RAIN AREA WAS EXPANDING EAST. CONDITIONS WILL LOWER
TO MVFR AND THEN EVENTUALLY TO IFR ON TUESDAY AS THE FRONTAL
SYSTEM MOVES THROUGH. SOME QUESTION IF CONDITIONS WILL START TO
IMPROVE AS THE DRIER AIR WORKS IN TUESDAY NIGHT. THE MODELS DON`T
THINK SO. WILL TRY TO INCREASE THE CEILINGS SOME LATE.
.OUTLOOK...NON VFR INTO LATE TUE NIGHT AND ACROSS FAR NE OH/NW PA
ON WED AND THU IN LAKE EFFECT SNOW SHOWERS.
&&
.MARINE...
SE WINDS WILL START INCREASING TONIGHT AND VEER TO SW ON TUE THEN TO
WEST TUE NIGHT WHILE INCREASING TO 20 TO 30 KNOTS AS COLD AIR BEHIND
A SERIES OF COLD FRONTS SPREADS ACROSS THE AREA. THUS A SCA WILL BE
NEEDED STARTING TUE NIGHT. WEST TO NW WINDS WILL SLOWLY DECREASE
LATER WED THRU EARLY FRI SO THE SCA MAY HAVE TO BE UP UNTIL SOMETIME
THU NIGHT. HIGH PRESSURE OVER THE UPPER LAKES EARLY FRI WILL SETTLE
OVER THE NORTHERN PART OF THE LAKES FOR SAT WHILE A LOW TRACKS NE
ACROSS THE SE STATES TO THE DELMARVA AREA BY EARLY SUN. THIS SHOULD
LEAD TO AN INCREASING NE FLOW ON SAT...HOWEVER MODEL DIFFERENCES
MAKE IT UNCERTAIN WHETHER THE WINDS WILL GET INTO SCA CRITERIA.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...DJB/TK
SHORT TERM...TK
LONG TERM...ADAMS
AVIATION...KIELTYKA
MARINE...ADAMS
AREA FORECAST DISCUSSION
NWS PORTLAND OR
231 PM PST TUE DEC 16 2014
.SYNOPSIS...THERE WILL BE A BREAK IN RAIN THIS AFTERNOON BEFORE RAIN
ASSOCIATED WITH A LOW WEST OF THE CENTRAL OREGON COAST...MOVES SOUTH
TO NORTH THIS EVENING THROUGH WEDNESDAY MORNING. SHOWERS WILL
PRIMARILY BE OVER THE HIGHER TERRAIN. AN UPPER TROUGH WILL MAINTAIN A
CHANCE FOR SHOWERS THROUGH WEDNESDAY EVENING. A MORE ORGANIZED FRONT
WILL BRING GUSTY WINDS AND LARGE SURF TO THE COAST...WITH RAIN
SPREADING INLAND THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS WILL
LIMIT SNOW TO THE HIGHEST PEAKS...BUT COLDER AIR BEHIND THE FRONT MAY
RESULT IN SOME SNOW SHOWERS FOR THE CASCADES PASSES FRIDAY EVENING
AND SATURDAY. A WARMER AND MOISTER WEATHER IS EXPECTED THIS WEEKEND.
&&
.SHORT TERM...TONIGHT THROUGH FRIDAY...SHOWERS HAVE PRETTY MUCH ENDED
OVER THE PORTLAND FORECAST AREA EARLY THIS AFTERNOON...EXCEPT FOR
VERY INFREQUENT ISOLATED SHOWER OVER THE SW WASHINGTON CASCADES.
SATELLITE IMAGERY SHOWS A SURFACE LOW AROUND 150 MILES WEST OF THE
SOUTHERN OREGON COAST...NEAR 42N 127W. THE HIGHER RESOLUTION
MODELS...HRRR AND RAP INITIALIZE BEST WITH THE LOW AND FORECAST RAIN
MOVING NORTH INTO LANE COUNTY SLIGHTLY EARLIER THAN THE OTHER MODELS.
HAVE TRENDED TOWARDS THIS EARLIER ARRIVAL...BUT ONLY HAVE FAIR
CONFIDENCE THAT THE TIMING WILL PAN OUT. ANY RAIN LATE THIS AFTERNOON
SHOULD BE FAIRLY LIGHT AND REMAIN WEST OF THE SOUTH AND CENTRAL
WILLAMETTE VALLEY.
THE LOW WILL MOVE CLOSER TO THE SOUTHERN OREGON COAST LATE THIS
AFTERNOON AND EVENING THEN MOVE ONTO THE CENTRAL OREGON COAST AS AN
UPPER TROUGH LATE TONIGHT...WITH SHOWERS MAINLY OVER THE HIGHER
TERRAIN THROUGH WEDNESDAY MORNING. SOME CLEARING EARLY WED MORNING
MAY RESULT IN SHALLOW FOG AND LOW CLOUDS IN SOME OF THE INTERIOR
VALLEYS...MAINLY SOUTH OF SALEM.
EASTERLY WINDS HAVE HELD ON TODAY WITH A TROUTDALE TO DALLES PRESSURE
GRADIENT HOLDING AROUND 5 MB. THIS GRADIENT SHOULD TIGHTEN A LITTLE
THIS EVENING AS THE LOW MOVES CLOSER TO THE COAST AND MAINTAIN GUSTS
AROUND 30 MPH THROUGH THE WESTERN COLUMBIA RIVER GORGE.
SHOWERS WILL CONTINUE WEDNESDAY...MAINLY FOR THE HIGHER TERRAIN AS
THE PARENT UPPER LEVEL TROUGH MOVES OVER THE PACIFIC NW. SHOWERS
SHOULD END OVERNIGHT AS AN UPPER RIDGE BUILDS OVER THE AREA AND
EXPECT THAT CLEARING SKIES AND LIGHT WINDS WILL LEAD TO SHALLOW FOG
FOR THE INTERIOR VALLEYS EARLY THURSDAY MORNING. MOST OF THURSDAY
WILL BE DRY WITH AN INCREASE OF MID AN HIGH LEVEL CLOUDS IN THE
AFTERNOON.
MODELS ARE IN GOOD AGREEMENT THAT A WELL ORGANIZED FRONT WILL BRING
GUSTY WINDS TO THE COAST THURSDAY EVENING WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. PRECIPITABLE WATER IS EXPECTED TO BE NEAR
AN INCH AND AN APPROACHING JET STREAK SHOULD PROVIDE GOOD LIFT AND
EXPECT THE HIGHEST RAINFALL TOTALS OF 0.75 TO 1 INCH ACROSS THE
COAST AND COAST RANGE THURSDAY NIGHT THROUGH FRIDAY MORNING. OTHER
AREAS SHOULD SEE BETWEEN 0.4 AND 0.60 INCH OF RAIN. SNOW LEVELS
SHOULD REMAIN ABOVE 5000 FEET DURING THE PEAK RAIN PERIOD...BUT LOWER
TO NEAR OR BELOW THE CASCADE PASSES BEHIND THE FRONT FRIDAY
AFTERNOON.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...A BROAD RIDGE OF HIGH
PRESSURE OVER THE WESTERN U.S. FLATTENS AS A STRONG LOW PRESSURE
SYSTEM OVER THE GULF OF ALASKA MOVES INLAND TO OUR NORTH. AS THIS
TROUGH MOVES ON SHORE SATURDAY...THE ASSOCIATED COLD FRONT MOVES
ONSHORE AND STALLS EAST-TO-WEST ACROSS NORTHWEST OREGON AND
SOUTHWEST WASHINGTON. THIS PUTS OUR AREA IN THE PATH OF RAIN
STARTING SATURDAY THROUGH MONDAY. SOME UNCERTAINTY EXISTS IN WHERE
THIS BOUNDARY WILL SET UP...WHICH WILL DETERMINE HOW MUCH RAINFALL
WE WILL GET. ON TUESDAY...GEFS ENSEMBLE SPAGHETTI PLOTS GET MESSY
AND SIGNIFICANT DIFFERENCES START TO SHOW UP BETWEEN THE GFS AND
ECMWF...DECREASING CONFIDENCE ON HOW THE REST OF THE WEEK WILL SHAPE
UP. AS OF NOW...THE MOST COMMON SOLUTION IS THAT HIGH PRESSURE
RIDGING WILL START TO BUILD BACK OVER THE WESTERN U.S. WHICH
SUGGESTS DRIER WEATHER STARTING TUESDAY...THOUGH UNCERTAINTY IS VERY
HIGH. -MCCOY
&&
.AVIATION...MAINLY VFR CONDITIONS ACROSS THE FORECAST AREA THIS
AFTERNOON...WITH A COUPLE NOTABLE EXCEPTIONS. IFR/LIFR CIGS
DEVELOPED THIS MORNING IN THE WILLAMETTE VALLEY KSLE SOUTHWARD...
AND HAVE LINGERED ALL DAY DUE TO LIGHT N-NE FLOW JAMMING THE LOW
CLOUDS AGAINST THE SOUTH END OF THE WILLAMETTE VALLEY. KSLE
APPEARS TO BE ON THE NORTHERN FRINGE OF THESE LOW CLOUDS...AND
WILL LIKELY REMAIN SO THROUGH THIS EVENING. CIGS WILL PROBABLY
DROP BACK DOWN TO NEAR THE DECK IN THESE AREAS TONIGHT AS -RA
DEVELOPS WITH OUR NEXT FRONTAL SYSTEM AND MOISTENS UP THE LOW
LEVEL AIR MASS.
ALSO EASTERLY UPSLOPE FLOW CAUSING MOUNTAIN OBSCURATIONS ALONG
THE EAST SLOPES AND CREST OF THE CASCADES...AND WILL LIKELY
CONTINUE TO DO SO OVERNIGHT TONIGHT.
WILL SEE AREAS -RA SPREAD NORTHWARD ACROSS MUCH OF THE FORECAST
AREA LATER TONIGHT...BUT IT APPEARS CIGS WILL GENERALLY REMAIN VFR
UNLESS OTHERWISE STATED ABOVE.WEAGLE
KPDX AND APPROACHES...VFR CIGS LIKELY REMAIN AT OR ABOVE 5 K FT
THROUGH THIS EVENING. SOME -RA IS POSSIBLE LATER TONIGHT AS
MOISTURE ASSOCIATED WITH AN OCCLUDED FRONT SPREADS NORTHWARD.
HOWEVER IT APPEARS CIGS SHOULD REMAIN VFR. LIGHT TO MODERATE
EASTERLY SFC WINDS THROUGH THIS EVENING. WEAGLE
&&
.MARINE...VISIBLE SATELLITE IMAGERY SHOWS A WELL-DEFINED LOW
PRESSURE SYSTEM ABOUT 150 NM WEST OF CRESCENT CITY CA. THIS SYSTEM
APPEARS TO HAVE REACHED ITS MAXIMUM STRENGTH WITH A CENTRAL
PRESSURE AROUND 995 MB. FORECAST MODELS APPEAR TO HAVE GENERALLY
CAUGHT UP WITH THE STRENGTH OF THIS SYSTEM AFTER LAGGING BEHIND
EARLIER TODAY. THE LOW WILL DRIFT E-NE TONIGHT...PUSHING INTO WRN
OREGON BY WED. IT APPEARS E-NE WINDS CURLING AROUND THIS LOW WILL
BE ENOUGH TO PUSH GUSTS TO 25 KT IN OUR FAR SW WATERS...SO ISSUED
A SCA FOR WINDS IN THIS AREA THIS EVENING. AS THE LOW WEAKENS...
WINDS ASSOCIATED WITH THIS SYSTEM SHOULD WEAKEN AS WELL.
THE NEXT RELATIVELY STRONG FRONTAL SYSTEM IS BEGINNING TO TAKE
SHAPE BETWEEN 160W-170W...AND MAY PRODUCE GALES FOR OUR WATERS AS
IT MOVES ONSHORE LATER THU/EARLY FRI. THERE IS A GOOD POTENTIAL
FOR COASTAL JET FORMATION WHICH WOULD ENHANCE WINDS JUST AHEAD OF
THE FRONT WITH GUSTS TO 45 KT POSSIBLE NEAR THE COAST THU NIGHT.
AFTER COORDINATION WITH WFO SEATTLE...DECIDED CONFIDENCE WAS HIGH
ENOUGH TO WARRANT A GALE WATCH FOR THIS SYSTEM. 12Z ECMWF/GFS SHOW
THIS SYSTEM TAKING A NEAR-IDEAL TRACK AND SPEED FOR DYNAMIC
FETCH...AND THIS SHOWS IN THE WAVE MODELS. ENP GUIDANCE SUGGESTS
A SOLID 17-21 FT SWELL WITH A DOMINANT PERIOD OF 16-20 SECONDS
FOLLOWS THE FRONT...PROBABLY ENOUGH TO WARRANT A HIGH SURF
ADVISORY FRIDAY. WEAGLE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR WINDS FROM 6 PM THIS EVENING TO
MIDNIGHT PST TONIGHT FOR WATERS FROM CASCADE HEAD TO
FLORENCE OR FROM 10 TO 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 11 PM
THIS EVENING TO 3 AM PST WEDNESDAY.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 9 AM TO
5 PM PST WEDNESDAY.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS MEDFORD OR
216 PM PST TUE DEC 16 2014
.DISCUSSION...PRECIPITATION AHEAD OF A SURFACE LOW NEAR 42N/128W IS ALREADY
REACHING CAPETOWN CALIFORNIA AND IS MOVING NORTH TO NORTHEAST. THE
RAP IS DOING FAIRLY WELL IN INITIALIZING THE POSITION OF THE LOW AND
QPF FIELDS THIS AFTERNOON AND HAVE LEANED TOWARDS THIS SOLUTION FOR
THIS EVENING. WINDS HAVE INCREASED AHEAD OF THE LOW IN THE SHASTA
VALLEY AND WILL LAST THROUGH THE NIGHT, BUT DO NOT EXPECT THEM TO
REACH ADVISORY CRITERIA. THE RAP SHOWS THE PRECIP FIELD BREAKING UP
INTO TWO PARTS THIS EVENING. ONE PART WILL MOVE NORTH OVER THE
MARINE WATERS, THE OTHER WILL CONTINUE TO PUSH EAST INTO NORTHERN
CAL AND INTO THE MOUNT SHASTA REGION. THE PARAMETERS ON THE NAM WITH
RESPECT TO SNOW NEAR AND AT MOUNT SHASTA HAVE CHANGED LITTLE FROM
THE PREVIOUS RUN. IT STILL LOOKS FAVORABLE FOR HEAVIER PRECIPITATION
TO DEVELOP LATER THIS EVENING AND TONIGHT DUE TO UPSLOPE FLOW AND
850 MB TEMPERATURES NEAR 0C. IN ADDITION 700MB FLOW IS FROM THE
SOUTH BETWEEN 40-50 KTS. THE MAIN QUESTION WILL BE HOW MUCH. CURRENT
THINKING IS THAT WE`LL HAVE A RAIN WET SNOW MIX TO START THIS
EVENING WITH MODEL SOUNDINGS RIGHT AT THE CUSP BETWEEN RAIN AND
SNOW. PRECIPITATION WILL INCREASE TONIGHT FORCING THE SNOW LEVEL
DOWN LOW ENOUGH TO GET INTO MOUNT SHASTA. SNOW RATIONS WILL BE LOW,
BUT QPF VALUES SUGGEST WE COULD PICK UP AT LEAST 3 INCHES OR MORE
NEAR THE INTERSTATE, ESPECIALLY BETWEEN MOUNT SHASTA AND DUNSMUIR.
IT`S POSSIBLE HIGHWAY 89 COULD GET UP TO 6 INCHES OR MORE BY
DAYBREAK WEDNESDAY.
THE UPPER TROUGH MOVES THROUGH WEDNESDAY MORNING AND THE UPPER FLOW
WILL BECOME WESTERLY WHICH WILL LIMIT THE AMOUNT OF PRECIPITATION
IN THE MOUNT SHASTA REGION. ELSEWHERE VALLEY RAIN AND MOUNTAIN
SNOW SHOWERS WILL LINGER, BUT WERE NOT EXPECTING ANYTHING
NOTEWORTHY WITH MINIMAL IMPACT ON PASSES. SOME LEFTOVER SHOWERS
WILL LINGER INTO WEDNESDAY EVENING, THEN END OVERNIGHT AS
SHORTWAVE RIDGING BUILDS INTO THE AREA. WE`LL CATCH A DRY BREAK ON
THURSDAY WITH THE RIDGE AXIS OVER THE AREA, BUT THIS WILL BE SHORT
LIVED. THE MODELS SHOW A STRONGER FRONT APPROACHING THE AREA
THURSDAY AFTERNOON BRINGING INCREASING SOUTH WINDS OVER THE MARINE
WATERS WHICH COULD GET CLOSE TO GALES.
THIS FRONT WILL PUSH INLAND THURSDAY NIGHT WITH PRECIPITATION
SPREADING OVER MUCH OF THE FORECAST AREA. THE HEAVIEST AMOUNTS WILL
BE ALONG THE COAST RANGE, COASTAL MOUNTAINS AND CASCADES. RIGHT NOW
SNOW LEVELS WILL START OUT HIGH THURSDAY EVENING, BUT WILL DROP
TO AROUND 4500 FEET EARLY FRIDAY MORNING. SO IT`S A GOOD BET THE
MOUNTAIN PASSES WILL GET ACCUMULATING SNOW STARTING LATE THURSDAY
NIGHT THROUGH FRIDAY MORNING. RIGHT NOW, IT LOOKS LIKE CRATER LAKE
COULD PICK UP AT LEAST 6 INCHES OR MORE...A FEW INCHES OVER
SISKIYOU SUMMIT AND HIGHWAY 140. KEEP IN MIND THE DETAILS ON THIS
WILL CHANGE, SO STAY TUNED FOR THE LATEST UPDATES, ESPECIALLY FOR
ANYONE PLANING ON TRAVELING THE WEEKEND BEFORE CHRISTMAS.
-PETRUCELLI
LONG-TERM FORECAST...SATURDAY THROUGH TUESDAY. A BROAD LONG WAVE
RIDGE WILL BUILD INTO THE WEST COAST SATURDAY AND SUNDAY...WITH
GENERALLY NORTHWEST FLOW ALOFT. SHORT WAVES RIDING OVER THE TOP OF
THE RIDGE WILL WEAKEN IT FROM SUNDAY NIGHT ON...BUT IT WILL REMAIN
IN PLACE THROUGH TUESDAY. THE FLOW ALOFT WILL BECOME MORE ZONAL
THOUGH.
THIS PATTERN WILL FORCE THE MAIN STORM TRACK TO THE NORTH OF THE
MEDFORD CWA...BUT THE AREA WILL STILL CATCH THE SOUTHERN END OF
SEVERAL SYSTEMS WHICH WILL MOVE ONSHORE DURING THIS INTERVAL. THE
STRONGEST OF THESE SYSTEMS WILL MOVE ONSHORE SATURDAY AFTERNOON AND
EVENING...AND AGAIN MONDAY. THE BULK OF THE ASSOCIATED PRECIPITATION
WILL FALL ALONG THE COAST...COAST RANGE...AND UMPQUA BASIN. AMOUNTS
WILL BE SIGNIFICANT BUT NOT EXCESSIVE...NO FLOODING PROBLEMS ARE
ANTICIPATED. SNOW LEVELS WILL START OFF BETWEEN 4000 AND 5000 FEET
SATURDAY...BUT WILL RISE TO ABOVE 7000 FEET SATURDAY NIGHT INTO
SUNDAY AND REMAIN ABOVE ALL BUT THE HIGHEST TERRAIN UNTIL IT LOWERS
SLIGHTLY TUESDAY NIGHT. SO...THE HEAVIEST SNOWS WILL OCCUR WITH THE
SATURDAY SYSTEM.
&&
.AVIATION...BASED ON THE 16/18Z TAF CYCLE...VFR CONDITIONS WILL
PREVAIL INITIALLY ACROSS THE MEDFORD CWA. AREAS OF MVFR CIGS IN
PRECIPITATION WILL DEVELOP THIS AFTERNOON ALONG THE SOUTH COAST
RANGE AND MOST OF SISKIYOU COUNTY WITH HIGHER TERRAIN BECOMING
OBSCURED. AREAS OF IFR CIGS/VSBYS IN LOW CLOUDS AND FOG WILL
DEVELOP OVER THE WESTERN VALLEYS LATE TONIGHT AND PERSIST THROUGH
MID-MORNING WEDNESDAY.
&&
.MARINE...UPDATED 900 AM PST TUE DEC 16 2014...HEAVY WEST
SWELL WILL GRADUALLY SUBSIDE TODAY. SURFACE LOW PRESSURE CENTERED
NEAR 130 WEST EARLY THIS MORNING WILL APPROACH AND THEN MOVE ONTO
THE NORTHERN CALIFORNIA COAST TONIGHT. THIS WILL RESULT IN
INCREASING SOUTH WINDS AND BUILDING SEAS...ESPECIALLY SOUTH OF
CAPE BLANCO AND BEYOND 10NM OFFSHORE...WHERE GALE FORCE WINDS ARE
EXPECTED. WINDS WILL DIMINISH AS THE LOW MOVES BY THIS EVENING
THROUGH WEDNESDAY MORNING. THURSDAY INTO FRIDAY A STRONGER FRONT
WILL PUSH THROUGH WITH ANOTHER ROUND OF STRONG SOUTH WINDS...RAIN...
AND STEEP SEAS. VERY HEAVY WEST SWELL AROUND 20 FEET WITH A DOMINANT
PERIOD OF 19 SECONDS WILL ARRIVE ON FRIDAY.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM PST
WEDNESDAY FOR CAZ082-083-282-284.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 1 AM PST WEDNESDAY FOR
PZZ356-370.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM PST WEDNESDAY
FOR PZZ350-356-370-376.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 AM PST WEDNESDAY FOR
PZZ376.
GALE WARNING UNTIL 7 PM PST THIS EVENING FOR PZZ376.
HAZARDOUS SEAS WARNING UNTIL 7 PM PST THIS EVENING FOR PZZ376.
$$
AREA FORECAST DISCUSSION
NWS PORTLAND OR
954 AM PST TUE DEC 16 2014
.SYNOPSIS...SHOWERS WILL DECREASE TODAY AS A WEAK UPPER TROUGH MOVES
NORTHEAST OF THE AREA. AFTER A BRIEF BREAK IN RAIN THIS AFTERNOON AND
EVENING ANOTHER UPPER TROUGH WILL BRING PERIODS OF RAIN...MAINLY TO
THE HIGHER ELEVATIONS TONIGHT AND WEDNESDAY. A MORE ORGANIZED FRONT
WILL BRING GUSTY WINDS AND LARGE SURF TO THE COAST...AND WIDESPREAD
RAIN THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS AND SUBTROPICAL
MOISTURE SPILLING INTO THE REGION WILL LIKELY BRING RAIN TO ALL BUT
THE HIGHEST PEAKS. COLDER AIR WILL MOVE IN BEHIND THE FRONT WITH SOME
SNOW SHOWERS FOR THE CASCADES PASSES POSSIBLE FRIDAY NIGHT AND
SATURDAY BEFORE ANOTHER WARMER SYSTEM RAISES THE SNOW LEVELS AGAIN
LATE IN THE WEEKEND
&&
.UPDATE...SHOWERS ARE QUICKLY MOVING NORTH OVER NW OREGON AND SW
WASHINGTON THIS MORNING AS A LOW IS SPINNING UP OFFSHORE THE NORTHERN
CALIFORNIA COAST. HAVE REMOVED POPS SOUTH OF SALEM FOR THE REST OF
THIS MORNING AND THE EARLY AFTERNOON...AND HAVE REDUCED POPS NORTH OF
SALEM WITH ISOLATED SHOWERS FOR THE INTERIOR VALLEYS AND SCATTERED
SHOWERS FOR THE HIGHER TERRAIN. SATELLITE AND SURFACE OBSERVATIONS
SHOWS PATCHY FOG IN THE INTERIOR VALLEYS OF SOUTHERN LANE
COUNTY...NEAR EUGENE...AND HAVE ADDED FOG IN THE FORECAST FOR THE
REMAINDER OF THE MORNING.
HAVE CONTINUED THE NORTHWARD TREND OF DISAPPEARING RAIN FOR THIS
AFTERNOON AND EVENING BY REMOVING POPS TO THE NORTH. HOWEVER...THE
POPS AT THIS TIME ARE REINTRODUCED TO THE SOUTH DUE TO THE LOW
SHIFTING INLAND. THE SNOW LEVEL IS AROUND 4000 FT THIS MORNING WITH
WEB CAMS SUGGESTING 1 TO 2 INCHES OF ACCUMULATING SNOW FOR THE CASCADE
PASSES OVERNIGHT.
SATELLITE IMAGERY IS SHOWING CYCLOGENESIS AROUND 200 MILES OFFSHORE OF
THE CALIFORNIA/OREGON BORDER THIS MORNING. THIS LOW MAY BE SLIGHTLY
DEEPER THAN THE PREVIOUS MODELS SUGGESTED AND EXPECT THE EASTERLY
SURFACE PRESSURE GRADIENT TO HANG ON A LITTLE LONGER. THE EASTERLY
WINDS WILL WEAKEN A LITTLE THIS MORNING AND AFTERNOON THAN INCREASE
AGAIN LATE THIS AFTERNOON AND EVENING. THE GRADIENT WILL NOT BE
PARTICULARLY STRONG WITH MODELS FORECASTING A TROUTDALE TO DALLES
GRADIENT AROUND 8 MB...BUT THIS IS STRONGER THAN THE PREVIOUS
FORECAST AND HAVE INCREASED THE EASTERLY WINDS FOR TONIGHT THROUGH
WED MORNING...MAINLY THROUGH THE COLUMBIA RIVER GORGE AND NORTHERN
AREAS. THE DEEPER LOW WILL ALSO RESULT IN A TIGHTER SOUTHERLY
GRADIENT WED AFTERNOON AS THE LOW MOVES INLAND AND HAVE INCREASED THE
SOUTHERLY WINDS FOR THE WILLAMETTE VALLEY A TAD.
THE UPPER TROUGH ASSOCIATED WITH THE FRONT/LOW OFFSHORE IS SPLITTING
AND RAIN FOR TONIGHT AND WEDNESDAY ACROSS NW OREGON AND SW WASHINGTON
IS NOT VERY IMPRESSIVE. MOST OF THE RAIN WILL BE FAR SOUTH OR FAR
NORTH OF US...BUT A PART OF THE UPPER TROUGH WILL APPROACH TONIGHT
AND MOVE OVER WEDNESDAY...MAINTAINING A CHANCE OF SHOWERS. THINK
MOST OF THESE SHOWERS WILL BE OVER THE HIGHER TERRAIN WITH THE
INTERIOR VALLEYS NOT SEEING MUCH RAIN. TJ
.PREVIOUS SHORT TERM...TODAY THROUGH FRIDAY...LIGHT RAIN PERSISTS
TODAY AS A WEAK FRONTAL SYSTEM CONTINUES TO PUSH EAST OF THE FORECAST
AREA EARLY THIS MORNING. SURFACE OBSERVATIONS ARE REPORTING BETWEEN
0.01-0.05" OF RAIN IN THE PAST 6 HOURS...EXCEPT FOR ALMOST 0.10" OF
PRECIP OVER THE COAST RANGE. THE NEXT FRONTAL SYSTEM CAN BE SEEN IN
INFRARED SATELLITE IMAGERY JUST OFF THE OREGON/CALIFORNIA COASTLINE
THIS MORNING. TEMPERATURES HAVE LOWERED TO 32-35 DEG F IN THE UPPER
PORTIONS OF THE HOOD RIVER VALLEY...WHERE SOME LIGHT SNOW
ACCUMULATIONS UP TO AN INCH OR SO ARE POSSIBLE THROUGH THIS MORNING.
EVEN WITH OFFSHORE FLOW PERSISTING...MODELS CONTINUE TO SHOW THE
EASTERLY GRADIENT STARTING TO SLACK OFF TODAY. GRADIENTS FURTHER
WEAKEN THROUGH LATE WED...AS HIGH PRESSURE SLOWLY WEAKENS EAST OF THE
CASCADES.
MODELS REMAIN CONSISTENT IN SHOWING MUCH OF THE ENERGY ASSOCIATED
WITH THIS NEXT LOW PRES SYSTEM HEADING SOUTH INTO NORTHERN CALIFORNIA
LATER TODAY. AS A RESULT...OFFSHORE LOW LEVEL FLOW BECOMES REINFORCED
WHILE FLOW ALOFT TURNS A BIT MORE SOUTHERLY...ALLOWING SHOWER
ACTIVITY TO DIMINISH BY THIS AFTERNOON. SHOWERS MAY LINGER LONGER
ALONG THE CENTRAL OREGON COAST THOUGH. MOISTURE BEGINS TO SPREAD
ACROSS THE AREA AS THE CENTER OF THE LOW PRES DRIFTS TOWARDS THE
OREGON/CALIFORNIA BORDER OVERNIGHT TONIGHT INTO WEDNESDAY MORNING.
THE UPPER LEVEL TROUGH AXIS MOVES INLAND MIDDAY WEDNESDAY AND
WEDNESDAY NIGHT... WHICH SHOULD BRING ANOTHER ROUND OF PRECIP TO THE
AREA. BRIEF UPPER LEVEL RIDGING DEVELOPS FOR THURSDAY...BUT A WARM
FRONT AHEAD OF THE NEXT ORGANIZED FRONTAL BAND COULD BRING A THREAT
FOR PRECIP BY EARLY THURSDAY AFTERNOON. EAST WINDS MAY PICK UP AGAIN
THROUGH THE GORGE AS THIS SYSTEM APPROACHES THE COAST. THIS STRONG
FRONTAL SYSTEM PUSHES INTO THE PACIFIC NORTHWEST FRIDAY...BRINGING A
DECENT BATCH OF PRECIP TO THE AREA AS WELL AS GUSTY SOUTH WINDS FOR
THE COAST.
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...FRIDAY NIGHT
THROUGH MONDAY...A COLD AIR UNSTABLE AIRMASS WILL FOLLOW A STRONG
FRONTAL SYSTEM AND KEEP SHOWERS GOING INTO FRIDAY NIGHT. SNOW LEVELS
SHOULD LOWER TO NEAR 4000 FT ON SO ACCUMULATING SNOW APPEARS LIKELY
FOR AT LEAST THE HIGHER PASSES. AN ADDITIONAL SHORTWAVE TROUGH OR TWO
COULD ENHANCE SHOWER ACTIVITY EARLY IN THE WEEKEND AND BRING MUCH
NEEDED SNOW TO THE HIGHER CASCADES.
MODELS GENERALLY AGREE SNOW LEVELS WILL RISE LATE IN THE WEEKEND AS A
WARM FRONT SLIDES INTO THE REGION. STRONG ZONAL FLOW WILL FOCUS
PERSISTENT AND HEAVIER RAIN ACROSS SOUTHWEST BRITISH COLUMBIA AND
WESTERN WASHINGTON LATE IN THE WEEKEND AND EARLY NEXT WEEK. FOR
NOW...IT APPEARS THE BULK OF THE HEAVIEST RAIN WILL REMAIN NORTH OF
OUR REGION...AND WHEN HEAVIER PRECIPITATION ARRIVES...IT WILL REMAIN
TRANSIENT ENOUGH ACROSS OUR FORECAST AREA TO MINIMIZE FLOOD
CONCERNS. NONETHELESS...THIS PATTERN CERTAINLY BEARS
WATCHING...PARTICULARLY ACROSS THE NORTHERN HALF OF THE FORECAST
AREA WHERE A SLIGHT SHIFT IN THE STORM TRACK COULD PUT US IN THE
PATH OF A MODEST FIRE HOSE AND FLOOD CONCERNS WILL RISE. /NEUMAN
&&
.AVIATION...MAINLY VFR CONDITIONS TODAY IN LIGHT TO MODERATE
OFFSHORE FLOW ACROSS FORECAST AREA. A FEW EXCEPTIONS THIS
MORNING...SOME LINGERING MVFR NEAR KAST AND SOME FOG IN THE
WILLAMETTE VALLEY SOUTH OF KCVO. ALSO EASTERLY UPSLOPE FLOW
CAUSING MOUNTAIN OBSCURATIONS ALONG THE EAST SLOPES AND CREST OF
THE CASCADES.
THE MVFR CIGS NEAR KAST SHOULD LIFT AS THE FRONTAL ZONE WHICH
BROUGHT -RA EARLY THIS MORNING CONTINUES TO DRIFT NORTH INTO
WASHINGTON. AS FOR THE LIFR/VLIFR CONDITIONS AROUND KEUG... THEY
WILL PROBABLY BE MORE STUBBORN AS LOW PRESSURE OFF THE NORTHERN CA
COAST CONTINUES TO PULL IN LIGHT N-NE FLOW...JAMMING LOW CLOUDS
AGAINST THE SOUTH END OF THE WILLAMETTE VALLEY. SUSPECT IT WILL
LIFT TO REGULAR IFR WITH CIGS ABOVE 500 FT BY MIDDAY...BUT WILL
PROBABLY DROP BACK DOWN TO NEAR THE DECK LATER TONIGHT AS -RA
REDEVELOPS WITH OUR NEXT FRONTAL SYSTEM.
KPDX AND APPROACHES...VFR CONDITIONS WITH CIGS BETWEEN 4K TO 6K
FT THIS MORNING RISING TO AROUND 12K FT THIS AFTERNOON. LIGHT TO
MODERATE EAST SFC WINDS THROUGH THIS EVENING. WEAGLE
&&
.MARINE...SATELLITE IMAGERY THIS MORNING SHOWS A WELL-DEFINED LOW
PRESSURE SYSTEM ABOUT 200 NM WEST OF CRESCENT CITY CA. THIS
SYSTEM APPEARS TO HAVE STRENGTHENED TO AROUND 995 MB BASED ON
SATELLITE ANALYSIS AND THE MAGNITUDE OF WINDS ASSOCIATED WITH THE
LOW. MODELS APPEAR TO BE INITIALIZING THIS LOW TOO WEAKLY...EVEN
THE 16Z RAP ONLY SHOWS A 1000 MB LOW IN THIS LOCATION. RAPIDSCAT
IMAGERY FROM ABOARD THE INTERNATIONAL SPACE STATION SHOWS
SATELLITE-DERIVED WINDS OF UP TO 40 KT IN SE QUADRANT OF THIS
LOW...AND BUOY 46002 IS GUSTING TO GALE FORCE IN THE NW QUADRANT
OF THE LOW. THIS SYSTEM WILL NEED TO BE WATCHED CLOSELY AS IT
DRIFTS NE TOWARD OREGON THE NEXT 24-36 HRS. HOWEVER IT APPEARS THE
LOW IS APPROACHING ITS MAXIMUM STRENGTH AND WILL LIKELY START
WEAKENING AS MODELS SUGGEST BY TONIGHT. THEREFORE WE DID NOT
DEVIATE TOO FAR FROM THE MODELS WITH OUR WIND/SWELL FORECAST IN
THE NEXT 1-2 DAYS.
THE NEXT RELATIVELY STRONG FRONTAL SYSTEM IS BEGINNING TO TAKE
SHAPE BETWEEN 150W-160W...AND MAY PRODUCE GALES FOR OUR WATERS AS
IT MOVES ONSHORE LATER THU/EARLY FRI. THERE IS A GOOD POTENTIAL
FOR COASTAL JET FORMATION WHICH WOULD ENHANCE WINDS JUST AHEAD OF
THE FRONT WITH GUSTS TO 45 KT POSSIBLE NEAR THE COAST THU NIGHT.
ENP GUIDANCE SUGGESTS A SOLID 16-20 FT SWELL WITH A DOMINANT
PERIOD OF 16-20 SECONDS FOLLOWS THE FRONT...POSSIBLY ENOUGH TO
WARRANT A HIGH SURF ADVISORY FRIDAY. WEAGLE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL NOON PST TODAY FOR WATERS
FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10 TO 60 NM-
WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL NOON PST TODAY
FOR COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR OUT 10 NM-
WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10
TO 60 NM-WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO
60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 2 PM
PST THIS AFTERNOON.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 11 PM
THIS EVENING TO 3 AM PST WEDNESDAY.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1049 PM EST WED DEC 17 2014
.SYNOPSIS...
BRISK WESTERLY WINDS WILL USHER IN COLDER AIR ALONG WITH SCATTERED
MAINLY MOUNTAIN SNOW SHOWERS THROUGH THE END OF THE WEEK. A WEAK
LOW PRESSURE AREA IS EXPECTED TO MOVE WELL SOUTH OF THE REGION
THIS WEEKEND. THERE ARE INDICATIONS THAT THE WEATHER PATTERN COULD
TURN MORE UNSETTLED FOR NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
NO REAL CHANGES MADE WITH THIS UPDATE OTHER THAN SOME MINOR
TEMPERATURE TWEAKS.
BEST CHANCE OF SOW SHOWERS WILL BE OVER THE MORE TRADITIONAL HIGH
TERRAIN AREAS OF THE WEST AND NORTH AS WE ESTABLISH A COLD WNW
FLOW OVER THE REGION. HRRR SHOWS PRECIP REMAINING CONFINED TO
MAINLY NWRN PA THROUGH THE OVERNIGHT AND LATEST OPERATIONAL
GUIDANCE SUPPORTS THIS.
WEST TO NW WINDS WILL AVERAGE 10-15 KTS WITH GUSTS IN THE 20S
LATE TODAY THROUGH TONIGHT.
LOW TEMPS AT DAYBREAK THURS WILL BE NEAR 20F ACROSS THE HIGHER
TERRAIN OF THE NORTH AND WEST...AND IN THE MID TO UPPER 20S
THROUGHOUT THE SUSQ VALLEY.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
COLD AIR WILL STAY IN PLACE ACROSS THE FCST AREA THURSDAY INTO
FRIDAY.
THURSDAY...WINDS AT THE SFC AND ALOFT WILL VEER JUST SLIGHTLY TO
THE NORTHWEST. SPEEDS OF 10-15 MPH AND GUSTS INTO THE L20S ARE
POSSIBLE OVER THE MOUNTAINS. LITTLE OF NO CHANGE IN THE BLANKET OF
STRATUS AND STRATOCU CLOUDS IS EXPECTED THURSDAY AND THU
NIGHT...AND THE RELATIVELY SHALLOW COLD AIR BLOWING OVER THE LOWER
GLAKES WILL CREATE MORE SHSN ACROSS THE NRN AND WRN MTNS.
ACCUMULATIONS WILL BE MINOR...AND CONFINED TO THE FAR NW AND VERY
HIGHEST ELEVATIONS. AS STATED BY PREVIOUS SHIFTS NO MORE THAN 2
INCHES IS EXPECTED THROUGHOUT THE SNOWBELT OF NW WARREN COUNTY ON
THE HIGH END...SO NO LES ADVISORIES PLANNED ATTM. GLIMPSES OF
SUN MAY DEVELOP AGAIN ACROSS THE LOWER SUSQ...NUDGING TEMPS INTO
THE LOWER 40S /NEAR NORMAL FOR MID DEC/. MAX TEMPS ACROSS THE NRN
AND WRN MTNS WILL BE IN THE U20S TO L30S.
SIMILAR TEMPS AND SKY COVER EXPECTED AGAIN FOR THU NIGHT WITH
ISOLATED TO SCTD MTN SNOW SHOWERS. LITTLE IN THE WAY OF
ADDITIONAL SNOW ACCUM IS EXPECTED THOUGH AS MOISTURE WILL
CONTINUE TO BE QUITE SHALLOW WITH THE SUBSIDENCE INVERSION BASE
AOB 5 KFT AGL. A FEW HIGHLY LOCALIZED AMOUNTS IN THE 2-3 INCH
RANGE ARE POSSIBLE ACROSS THE FAVORED PERENNIAL SNOWBELT OF WARREN
COUNTY DURING THE 24 HOUR PERIOD ENDING 12Z FRI.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE PATTERN WILL REMAIN SEASONABLY COLD AND BRISK THROUGH THE END
OF THE WEEK. LARGE SCALE SUBSIDENCE ASSOCIATED WITH SURFACE HIGH
MIGRATING EASTWARD FROM THE UPPER MIDWEST ACROSS ONTARIO/QUEBEC
SHOULD BRING AN END TO NUISANCE/MINOR SNOW SHOWER ACTIVITY AND
LINGERING FLURRIES OVER THE NW ALLEGHENIES BY FRI NGT. CLEAR SKIES
AND CALM/LIGHT WINDS SHOULD ALLOW MIN TEMPS TO DIP INTO THE TEENS
IN THE NORTHERN MTNS SATURDAY MORNING.
CONCERNING THE WEEKEND SYSTEM...
HOPES FOR A SIGNIFICANT STORM THIS WEEKEND CONTINUE TO FADE WITH
THE LATEST MODELS CONTINUING TO SHOW A MUCH WEAKER/SUPPRESSED AND
DISJOINTED SYSTEM AS THE CONSENSUS SOLUTION. IN ADDITION..THE
RISK FOR ACCUMULATING LIGHT SNOW HAS ALSO NOTABLY DECREASED...BUT
NOT TOTALLY EVAPORATED. THAT SAID THERE IS STILL A NON-TRIVIAL
CHANCE THAT MOST PRECIP REMAINS SOUTH OF PA AND THE WEEKEND TURNS
OUT DRY FOR MOST LOCATIONS. EARLY WEEK MODEL SIMULATIONS FOR A
MAJOR STORM HAVE ALL BUT TRENDED TO A VIRTUAL NON EVENT FOR OUR
AREA.
THE PROGRESSIVE SPLIT STREAM ENERGY ALOFT MOVING EAST FROM THE
MID MS VLY NEVER REALLY ORGANIZES AS IT ATTEMPTS TO OVERRUN A
RETREATING AREA OF MODESTLY STRONG HP/RIDGING OVER THE NORTHEAST
AND EASTERN CANADA. AS SUCH DOWNPLAYED PCPN POTENTIAL AND TRIMMED
POPS BACK BY 10-20 PCT. THE NEW WRINKLE IN THIS FORECAST CYCLE IS
FOR A SECOND PIECE OF ENERGY /WHAT APPEARS TO BE THE MAIN SFC LOW/
LIFTING NORTH FROM NEAR THE FL/GA COAST AND TRACKING UP/OFFSHORE
THE EAST COAST SUN THRU TUE.
THE SPLIT FLOW PATTERN OVER THE CONUS IS EXPECTED TO BECOME HIGHLY
AMPLIFIED WITH A VERY DEEP NEGATIVELY TILTED TROUGH EVOLVING EAST
OF THE ROCKIES...LIKELY SPAWNING AN INTENSE SFC LOW OVER THE
GREAT LAKES/MID ATLANTIC/NORTHEAST REGIONS AROUND THE CHRISTMAS
EVE TIME FRAME. FOR WHAT ITS WORTH...BOTH THE 17/12Z GFS AND EC
ARE FORECASTING A RECORD LOW MSLP SUB 970MB CYCLONE INVOF LAKE
HURON AT 00Z ON 25 DEC. THIS SYSTEM WILL LIKELY GATHER MORE AND
MORE ATTENTION AS WE MOVE CLOSER TO THE HOLIDAY. THE GOOD NEWS FOR
TRAVELERS/BAD NEWS FOR SNOW CROWS IS THAT CURRENT PROJECTIONS
WOULD PLACE CENTRAL PA INITIALLY IN THE "WARM" SIDE OF THE DEEP
STORM FAVORING RAIN VS. SNOW. IT ALSO LOOKS QUITE WINDY ASSUMING
THE DEEP LOW VERIFIES.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
WIDESPREAD STRATO CU AND PERSISTENT MVFR TO IFR CIGS WITH
ISOLATED-SCATTERED AND GENERALLY BRIEF MVFR TO IFR VSBYS IN SNOW
SHOWERS WILL OCCUR ACROSS THE NW MTNS AND LAUREL HIGHLANDS /INVOF
KBFD AND KJST/ THROUGH FRIDAY MORNING. CONDITIONS ACROSS THE
CENTRAL MTNS WILL VARY BETWEEN LOW END VFR...AND MVFR CIGS.
GUSTY WEST TO WNW WINDS /UP AROUND 25 KTS AT TIMES/ WILL ADD SOME
MECHANICAL TURBULENCE DURING TAKEOFF AND FAP TO REGIONAL AIRFIELDS
THIS EVENING THROUGH THURSDAY. VFR CIGS AND VSBYS SHOULD CONTINUE
OVERNIGHT THROUGH THE EASTERN TAF SITES.
OUTLOOK...
THU-FRI...MVFR CIGS POSS NW. OTHERWISE NO SIG WX EXPECTED.
SAT-SUN...LIGHT SNOW/REDUCED VSBY POSSIBLE ...MAINLY ALONG THE MD
BORDER.
MONDAY...MAINLY VFR. HOWEVER...AREAS OF MVFR STRATO CU ARE
POSSIBLE IN DEVELOPING SERLY LOW LEVEL FLOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
924 PM EST WED DEC 17 2014
.SYNOPSIS...
BRISK WESTERLY WINDS WILL USHER IN COLDER AIR ALONG WITH SCATTERED
MAINLY MOUNTAIN SNOW SHOWERS THROUGH THE END OF THE WEEK. A WEAK
LOW PRESSURE AREA IS EXPECTED TO MOVE WELL SOUTH OF THE REGION
THIS WEEKEND. THERE ARE INDICATIONS THAT THE WEATHER PATTERN COULD
TURN MORE UNSETTLED FOR NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
NO REAL CHANGES MADE WITH THIS UPDATE OTHER THAN SOME MINOR
TEMPERATURE TWEAKS.
BEST CHANCE OF SOW SHOWERS WILL BE OVER THE MORE TRADITIONAL HIGH
TERRAIN AREAS OF THE WEST AND NORTH AS WE ESTABLISH A COLD WNW
FLOW OVER THE REGION. HRRR SHOWS PRECIP REMAINING CONFINED TO
MAINLY NWRN PA THROUGH THE OVERNIGHT AND LATEST OPERATIONAL
GUIDANCE SUPPORTS THIS.
WEST TO NW WINDS WILL AVERAGE 10-15 KTS WITH GUSTS IN THE 20S
LATE TODAY THROUGH TONIGHT.
LOW TEMPS AT DAYBREAK THURS WILL BE NEAR 20F ACROSS THE HIGHER
TERRAIN OF THE NORTH AND WEST...AND IN THE MID TO UPPER 20S
THROUGHOUT THE SUSQ VALLEY.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
COLD AIR WILL STAY IN PLACE ACROSS THE FCST AREA THURSDAY INTO
FRIDAY.
THURSDAY...WINDS AT THE SFC AND ALOFT WILL VEER JUST SLIGHTLY TO
THE NORTHWEST. SPEEDS OF 10-15 MPH AND GUSTS INTO THE L20S ARE
POSSIBLE OVER THE MOUNTAINS. LITTLE OF NO CHANGE IN THE BLANKET OF
STRATUS AND STRATOCU CLOUDS IS EXPECTED THURSDAY AND THU
NIGHT...AND THE RELATIVELY SHALLOW COLD AIR BLOWING OVER THE LOWER
GLAKES WILL CREATE MORE SHSN ACROSS THE NRN AND WRN MTNS.
ACCUMULATIONS WILL BE MINOR...AND CONFINED TO THE FAR NW AND VERY
HIGHEST ELEVATIONS. AS STATED BY PREVIOUS SHIFTS NO MORE THAN 2
INCHES IS EXPECTED THROUGHOUT THE SNOWBELT OF NW WARREN COUNTY ON
THE HIGH END...SO NO LES ADVISORIES PLANNED ATTM. GLIMPSES OF
SUN MAY DEVELOP AGAIN ACROSS THE LOWER SUSQ...NUDGING TEMPS INTO
THE LOWER 40S /NEAR NORMAL FOR MID DEC/. MAX TEMPS ACROSS THE NRN
AND WRN MTNS WILL BE IN THE U20S TO L30S.
SIMILAR TEMPS AND SKY COVER EXPECTED AGAIN FOR THU NIGHT WITH
ISOLATED TO SCTD MTN SNOW SHOWERS. LITTLE IN THE WAY OF
ADDITIONAL SNOW ACCUM IS EXPECTED THOUGH AS MOISTURE WILL
CONTINUE TO BE QUITE SHALLOW WITH THE SUBSIDENCE INVERSION BASE
AOB 5 KFT AGL. A FEW HIGHLY LOCALIZED AMOUNTS IN THE 2-3 INCH
RANGE ARE POSSIBLE ACROSS THE FAVORED PERENNIAL SNOWBELT OF WARREN
COUNTY DURING THE 24 HOUR PERIOD ENDING 12Z FRI.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE PATTERN WILL REMAIN SEASONABLY COLD AND BRISK THROUGH THE END
OF THE WEEK. LARGE SCALE SUBSIDENCE ASSOCIATED WITH SURFACE HIGH
MIGRATING EASTWARD FROM THE UPPER MIDWEST ACROSS ONTARIO/QUEBEC
SHOULD BRING AN END TO NUISANCE/MINOR SNOW SHOWER ACTIVITY AND
LINGERING FLURRIES OVER THE NW ALLEGHENIES BY FRI NGT. CLEAR SKIES
AND CALM/LIGHT WINDS SHOULD ALLOW MIN TEMPS TO DIP INTO THE TEENS
IN THE NORTHERN MTNS SATURDAY MORNING.
CONCERNING THE WEEKEND SYSTEM...
HOPES FOR A SIGNIFICANT STORM THIS WEEKEND CONTINUE TO FADE WITH
THE LATEST MODELS CONTINUING TO SHOW A MUCH WEAKER/SUPPRESSED AND
DISJOINTED SYSTEM AS THE CONSENSUS SOLUTION. IN ADDITION..THE
RISK FOR ACCUMULATING LIGHT SNOW HAS ALSO NOTABLY DECREASED...BUT
NOT TOTALLY EVAPORATED. THAT SAID THERE IS STILL A NON-TRIVIAL
CHANCE THAT MOST PRECIP REMAINS SOUTH OF PA AND THE WEEKEND TURNS
OUT DRY FOR MOST LOCATIONS. EARLY WEEK MODEL SIMULATIONS FOR A
MAJOR STORM HAVE ALL BUT TRENDED TO A VIRTUAL NON EVENT FOR OUR
AREA.
THE PROGRESSIVE SPLIT STREAM ENERGY ALOFT MOVING EAST FROM THE
MID MS VLY NEVER REALLY ORGANIZES AS IT ATTEMPTS TO OVERRUN A
RETREATING AREA OF MODESTLY STRONG HP/RIDGING OVER THE NORTHEAST
AND EASTERN CANADA. AS SUCH DOWNPLAYED PCPN POTENTIAL AND TRIMMED
POPS BACK BY 10-20 PCT. THE NEW WRINKLE IN THIS FORECAST CYCLE IS
FOR A SECOND PIECE OF ENERGY /WHAT APPEARS TO BE THE MAIN SFC LOW/
LIFTING NORTH FROM NEAR THE FL/GA COAST AND TRACKING UP/OFFSHORE
THE EAST COAST SUN THRU TUE.
THE SPLIT FLOW PATTERN OVER THE CONUS IS EXPECTED TO BECOME HIGHLY
AMPLIFIED WITH A VERY DEEP NEGATIVELY TILTED TROUGH EVOLVING EAST
OF THE ROCKIES...LIKELY SPAWNING AN INTENSE SFC LOW OVER THE
GREAT LAKES/MID ATLANTIC/NORTHEAST REGIONS AROUND THE CHRISTMAS
EVE TIME FRAME. FOR WHAT ITS WORTH...BOTH THE 17/12Z GFS AND EC
ARE FORECASTING A RECORD LOW MSLP SUB 970MB CYCLONE INVOF LAKE
HURON AT 00Z ON 25 DEC. THIS SYSTEM WILL LIKELY GATHER MORE AND
MORE ATTENTION AS WE MOVE CLOSER TO THE HOLIDAY. THE GOOD NEWS FOR
TRAVELERS/BAD NEWS FOR SNOW CROWS IS THAT CURRENT PROJECTIONS
WOULD PLACE CENTRAL PA INITIALLY IN THE "WARM" SIDE OF THE DEEP
STORM FAVORING RAIN VS. SNOW. IT ALSO LOOKS QUITE WINDY ASSUMING
THE DEEP LOW VERIFIES.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
WIDESPREAD STRATO CU AND PERSISTENT MVFR TO IFR CIGS WITH
ISOLATED-SCATTERED AND GENERALLY BRIEF MVFR TO IFR VSBYS IN SNOW
SHOWERS WILL OCCUR ACROSS THE NW MTNS AND LAUREL HIGHLANDS /INVOF
KBFD AND KJST/ THROUGH FRIDAY MORNING. CONDITIONS ACROSS THE
CENTRAL MTNS AND SUSQ VALLEY WILL VARY BETWEEN LOW END VFR...AND
MVFR CIGS.
GUSTY WEST TO WNW WINDS /UP AROUND 25 KTS AT TIMES/ WILL ADD SOME
MECHANICAL TURBULENCE DURING TAKEOFF AND FAP TO REGIONAL AIRFIELDS
THIS AFTERNOON THROUGH THURSDAY.
A SECONDARY COLD FRONT AND COMPACT UPPER AIR DISTURBANCE DROPPING
SE ACROSS THE REGION LATE TODAY AND EARLY TONIGHT COULD BRING
SOME BRIEFLY HEAVIER SNOW SHOWERS...WITH A COATING TO 1/2 INCH
POSSIBLE EVEN ACROSS THE CENTRAL MTN AND SUSQ VALLEY AIRFIELDS.
OTHERWISE...NOT A LOT GOING ON TILL MAYBE JUST BEFORE CHRISTMAS.
THERE COULD BE WIDESPREAD RAIN SHOWER ACTIVITY AROUND AS A POTENT
SFC AND UPPER LOW TRACKS NE TWD THE OHIO RIVER VALLEY.
OUTLOOK...
THU-FRI...MVFR CIGS POSS NW. OTHERWISE NO SIG WX EXPECTED.
SAT-SUN...LIGHT SNOW/REDUCED VSBY POSSIBLE ...MAINLY ALONG THE MD
BORDER.
MONDAY...MAINLY VFR. HOWEVER...AREAS OF MVFR STRATO CU ARE
POSSIBLE IN DEVELOPING SERLY LOW LEVEL FLOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
710 PM EST WED DEC 17 2014
.SYNOPSIS...
BRISK WESTERLY WINDS WILL BRING IN COLDER AIR AND SCATTERED MAINLY
MOUNTAIN SNOW SHOWERS THROUGH THE END OF THE WEEK. A WEAK LOW
PRESSURE AREA IS EXPECTED TO MOVE WELL SOUTH OF THE REGION THIS
WEEKEND. THERE ARE INDICATIONS THAT THE WEATHER PATTERN COULD TURN
MORE UNSETTLED FOR NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
MAIN CHANGE TO THE NEAR TERM WAS TO TRIM POPS BACK MORE TO THE
TRADITIONAL HIGH TERRAIN AREAS OF THE WEST AND NORTH AS WE
ESTABLISH A COLD WNW FLOW OVER THE REGION. HRRR SHOWS PRECIP
REMAINING CONFINED TO MAINLY NWRN PA THROUGH THE OVERNIGHT AND
LATEST OPERATIONAL GUIDANCE SUPPORTS THIS.
WEST TO NW WINDS WILL AVERAGE 10-15 KTS WITH GUSTS IN THE 20S
LATE TODAY THROUGH TONIGHT.
LOW TEMPS AT DAYBREAK THURS WILL BE NEAR 20F ACROSS THE HIGHER
TERRAIN OF THE NORTH AND WEST...AND IN THE MID TO UPPER 20S
THROUGHOUT THE SUSQ VALLEY.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
COLD AIR WILL STAY IN PLACE ACROSS THE FCST AREA THURSDAY INTO
FRIDAY.
THURSDAY...WINDS AT THE SFC AND ALOFT WILL VEER JUST SLIGHTLY TO
THE NORTHWEST. SPEEDS OF 10-15 MPH AND GUSTS INTO THE L20S ARE
POSSIBLE OVER THE MOUNTAINS. LITTLE OF NO CHANGE IN THE BLANKET OF
STRATUS AND STRATOCU CLOUDS IS EXPECTED THURSDAY AND THU
NIGHT...AND THE RELATIVELY SHALLOW COLD AIR BLOWING OVER THE LOWER
GLAKES WILL CREATE MORE SHSN ACROSS THE NRN AND WRN MTNS.
ACCUMULATIONS WILL BE MINOR...AND CONFINED TO THE FAR NW AND VERY
HIGHEST ELEVATIONS. AS STATED BY PREVIOUS SHIFTS NO MORE THAN 2
INCHES IS EXPECTED THROUGHOUT THE SNOWBELT OF NW WARREN COUNTY ON
THE HIGH END...SO NO LES ADVISORIES PLANNED ATTM. GLIMPSES OF
SUN MAY DEVELOP AGAIN ACROSS THE LOWER SUSQ...NUDGING TEMPS INTO
THE LOWER 40S /NEAR NORMAL FOR MID DEC/. MAX TEMPS ACROSS THE NRN
AND WRN MTNS WILL BE IN THE U20S TO L30S.
SIMILAR TEMPS AND SKY COVER EXPECTED AGAIN FOR THU NIGHT WITH
ISOLATED TO SCTD MTN SNOW SHOWERS. LITTLE IN THE WAY OF
ADDITIONAL SNOW ACCUM IS EXPECTED THOUGH AS MOISTURE WILL
CONTINUE TO BE QUITE SHALLOW WITH THE SUBSIDENCE INVERSION BASE
AOB 5 KFT AGL. A FEW HIGHLY LOCALIZED AMOUNTS IN THE 2-3 INCH
RANGE ARE POSSIBLE ACROSS THE FAVORED PERENNIAL SNOWBELT OF WARREN
COUNTY DURING THE 24 HOUR PERIOD ENDING 12Z FRI.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE PATTERN WILL REMAIN SEASONABLY COLD AND BRISK THROUGH THE END
OF THE WEEK. LARGE SCALE SUBSIDENCE ASSOCIATED WITH SURFACE HIGH
MIGRATING EASTWARD FROM THE UPPER MIDWEST ACROSS ONTARIO/QUEBEC
SHOULD BRING AN END TO NUISANCE/MINOR SNOW SHOWER ACTIVITY AND
LINGERING FLURRIES OVER THE NW ALLEGHENIES BY FRI NGT. CLEAR SKIES
AND CALM/LIGHT WINDS SHOULD ALLOW MIN TEMPS TO DIP INTO THE TEENS
IN THE NORTHERN MTNS SATURDAY MORNING.
CONCERNING THE WEEKEND SYSTEM...
HOPES FOR A SIGNIFICANT STORM THIS WEEKEND CONTINUE TO FADE WITH
THE LATEST MODELS CONTINUING TO SHOW A MUCH WEAKER/SUPPRESSED AND
DISJOINTED SYSTEM AS THE CONSENSUS SOLUTION. IN ADDITION..THE
RISK FOR ACCUMULATING LIGHT SNOW HAS ALSO NOTABLY DECREASED...BUT
NOT TOTALLY EVAPORATED. THAT SAID THERE IS STILL A NON-TRIVIAL
CHANCE THAT MOST PRECIP REMAINS SOUTH OF PA AND THE WEEKEND TURNS
OUT DRY FOR MOST LOCATIONS. EARLY WEEK MODEL SIMULATIONS FOR A
MAJOR STORM HAVE ALL BUT TRENDED TO A VIRTUAL NON EVENT FOR OUR
AREA.
THE PROGRESSIVE SPLIT STREAM ENERGY ALOFT MOVING EAST FROM THE
MID MS VLY NEVER REALLY ORGANIZES AS IT ATTEMPTS TO OVERRUN A
RETREATING AREA OF MODESTLY STRONG HP/RIDGING OVER THE NORTHEAST
AND EASTERN CANADA. AS SUCH DOWNPLAYED PCPN POTENTIAL AND TRIMMED
POPS BACK BY 10-20 PCT. THE NEW WRINKLE IN THIS FORECAST CYCLE IS
FOR A SECOND PIECE OF ENERGY /WHAT APPEARS TO BE THE MAIN SFC LOW/
LIFTING NORTH FROM NEAR THE FL/GA COAST AND TRACKING UP/OFFSHORE
THE EAST COAST SUN THRU TUE.
THE SPLIT FLOW PATTERN OVER THE CONUS IS EXPECTED TO BECOME HIGHLY
AMPLIFIED WITH A VERY DEEP NEGATIVELY TILTED TROUGH EVOLVING EAST
OF THE ROCKIES...LIKELY SPAWNING AN INTENSE SFC LOW OVER THE
GREAT LAKES/MID ATLANTIC/NORTHEAST REGIONS AROUND THE CHRISTMAS
EVE TIME FRAME. FOR WHAT ITS WORTH...BOTH THE 17/12Z GFS AND EC
ARE FORECASTING A RECORD LOW MSLP SUB 970MB CYCLONE INVOF LAKE
HURON AT 00Z ON 25 DEC. THIS SYSTEM WILL LIKELY GATHER MORE AND
MORE ATTENTION AS WE MOVE CLOSER TO THE HOLIDAY. THE GOOD NEWS FOR
TRAVELERS/BAD NEWS FOR SNOW CROWS IS THAT CURRENT PROJECTIONS
WOULD PLACE CENTRAL PA INITIALLY IN THE "WARM" SIDE OF THE DEEP
STORM FAVORING RAIN VS. SNOW. IT ALSO LOOKS QUITE WINDY ASSUMING
THE DEEP LOW VERIFIES.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
WIDESPREAD STRATO CU AND PERSISTENT MVFR TO IFR CIGS WITH
ISOLATED-SCATTERED AND GENERALLY BRIEF MVFR TO IFR VSBYS IN SNOW
SHOWERS WILL OCCUR ACROSS THE NW MTNS AND LAUREL HIGHLANDS /INVOF
KBFD AND KJST/ THROUGH FRIDAY MORNING. CONDITIONS ACROSS THE
CENTRAL MTNS AND SUSQ VALLEY WILL VARY BETWEEN LOW END VFR...AND
MVFR CIGS.
GUSTY WEST TO WNW WINDS /UP AROUND 25 KTS AT TIMES/ WILL ADD SOME
MECHANICAL TURBULENCE DURING TAKEOFF AND FAP TO REGIONAL AIRFIELDS
THIS AFTERNOON THROUGH THURSDAY.
A SECONDARY COLD FRONT AND COMPACT UPPER AIR DISTURBANCE DROPPING
SE ACROSS THE REGION LATE TODAY AND EARLY TONIGHT COULD BRING
SOME BRIEFLY HEAVIER SNOW SHOWERS...WITH A COATING TO 1/2 INCH
POSSIBLE EVEN ACROSS THE CENTRAL MTN AND SUSQ VALLEY AIRFIELDS.
OTHERWISE...NOT A LOT GOING ON TILL MAYBE JUST BEFORE CHRISTMAS.
THERE COULD BE WIDESPREAD RAIN SHOWER ACTIVITY AROUND AS A POTENT
SFC AND UPPER LOW TRACKS NE TWD THE OHIO RIVER VALLEY.
OUTLOOK...
THU-FRI...MVFR CIGS POSS NW. OTHERWISE NO SIG WX EXPECTED.
SAT-SUN...LIGHT SNOW/REDUCED VSBY POSSIBLE ...MAINLY ALONG THE MD
BORDER.
MONDAY...MAINLY VFR. HOWEVER...AREAS OF MVFR STRATO CU ARE
POSSIBLE IN DEVELOPING SERLY LOW LEVEL FLOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
219 AM EST TUE DEC 16 2014
.SYNOPSIS...
SEASONAL TEMPERATURES WILL RETURN BEHIND A COLD FRONT WHICH WILL
PASS THROUGH ON TUESDAY EVENING. SCATTERED MOUNTAIN SNOW SHOWERS
ARE THEN EXPECTED FOR MID AND LATE WEEK. CONFIDENCE IS LOW
CONCERNING ALL DETAILS AND POTENTIAL IMPACTS ASSOCIATED WITH A LOW
PRESSURE SYSTEM EXPECTED TO TRACK NORTHEAST FROM THE GULF COAST
STATES OFF THE EAST COAST THIS WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
UPPER LOW SPINNING OVER NRN IL WILL FILL SLIGHTLY AND SLIDE
EASTWARD COVERING LWR MI BY EVENING. THE LARGER TROUGH WILL START
TO ABSORB THIS FEATURE. COMPLICATED FRONTAL FEATURES TO OUR WEST
WILL NOT SIMPLIFY MUCH AS THE SLIGHTLY DIFFERENT AIR MASS MOVES IN
LATER TODAY.
DESPITE +8C 8H TEMPS...WE ARE SEEING LITTLE BENEFIT FROM THESE
UNUSUALLY MILD TEMPS HERE AT THE SFC DUE TO LUDICROUS INVERSION.
LOW STRATUS STILL STUCK IN THE NE HALF OF THE AREA AND PATCHES IN
THE SOUTH AS WELL. THIS SHOULD NOT CHANGE MUCH UNTIL LATE
MORNING...WHEN SOME LARGER HOLES DUE TO SOME MIXING MAY APPEAR IN
THE EAST. FOG IS NOT DENSE ANYWHERE AT 07Z...BUT THE WINDWARD
SLOPES OF THE MTS MAY HAVE A LITTLE DRIZZLE. SUB FREEZING TEMPS IN
THE S...BUT THIS IS ALSO WHERE THERE ARE NO/LESS LOWER CLOUDS TO
MAKE SPRINKLES.
THE FIRST ARM OF SHOWERS ASSOCIATED WITH THIS COMPLEX
CIRCULATION/PATTERN WILL APPROACH THE AREA THIS MORNING...BUT
LATEST GUIDANCE CONTINUES TO HOLD IT OFF A LITTLE LATER.
THUS...WILL KEEP POPS LOW IN THE CENTRAL AND EAST FOR THE MORNING.
NOT UNTIL 14-15Z WILL PRECIP BE CERTAIN OVER THE WESTERN
MOUNTAINS. BUT ALL MODEL GUIDANCE MAKES NUMEROUS SHOWERS OR EVEN
MORE-WIDESPREAD COVERAGE OVER MOST IF NOT ALL OF THE AREA BY
20Z. DRY SLOT MOVES IN FROM THE SOUTHWEST...BUT WESTERLY FLOW
BEHIND THE OCCLUSION WILL KEEP LOTS OF CLOUD COVER AND SCT SHRA
OVER THE WEST LATER IN THE AFTN.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/...
UPPER PATTERN WOBBLES ITSELF INTO A BROAD UPPER LOW WITH A FEW
CLOSED CONTOURS OVER THE GREAT LAKES AND LOWER ONT/SRN QUE.
MOISTURE PULLED AROUND THE SYSTM AND PULLED FROM THE GREAT LAKES
WILL ASCEND THE WRN HIGHLANDS AND CREATE NUMEROUS SHOWERS FOR
TONIGHT. LESS COVERAGE WILL BE HAD LATER TONIGHT AND WEDNESDAY
MORNING...BUT SHOWERS WILL CONTINUE INTO WEDNESDAY AS THE UPPER
LOW CENTER SLIDES EAST AND THE COLDER AIR FILTERS IN. THIS SHOULD
TURN ANY SHOWERS OVER TO SNOW SHOWERS WED MORNING. DOWNSLOPE
SHOULD KEEP IT PARTLY TO MOSTLY SUNNY IN THE SE. SOME VERY LIGHT
ACCUMS COULD OCCUR ON THE WRN MTS. IT WILL GET KIND OF WINDY ON
WED - ESP IN THE LAURELS WHERE GUSTS COULD GET INTO THE 30S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
A RATHER POTENT SHORTWAVE TROUGH WILL PIVOT EASTWARD FROM THE
GREAT LAKES AND CROSS THE AREA WED NGT BEHIND THE DEPARTING
SURFACE LOW LIFTING SLOWLY NORTH FROM MAINE INTO NEW BRUNSWICK
CANADA. A REINFORCING SHOT OF COLD AIR ALOFT SHOULD ACCOMPANY THE
TRAILING SHORTWAVE WHICH MAY ACT TO BRIEFLY ENHANCE POST FRONTAL
LAKE EFFECT AND UPSLOPE SNOW SHOWERS OVER THE WESTERN HIGHLANDS.
ITS NOT OUT OF THE QUESTION THAT THE STRONG VORTMAX COULD INDUCE
SNOW SHOWERS EAST OF THE ALLEGHENY FRONT WED NGT HOWEVER THE
GLOBAL MODEL QPFS ARE NOT IN FAVOR OF THIS OUTCOME. DESPITE A
WELL ALIGNED WNW FLOW AND FAIRLY STRONG LOW LEVEL COLD AIR
ADVECTION...MODEL SOUNDINGS SHOW RATHER SHALLOW MOISTURE/LOW
INVERSION HGTS ALONG WITH DRY AIR WHICH SHOULD LIMIT MAX SNOW
ACCUM POTENTIAL (POTENTIAL FOR THIS MUCH OR WORST CASE) OVER THE
NW MTNS TO 2-3 INCHES BY THU MORNING...WITH AROUND 1 INCH ACCUM
THE MOST LIKELY OUTCOME. OVERALL THE GENERAL WEATHER TREND IN
CENTRAL PA WILL BE TOWARD A BRISK AND COLDER PATTERN WED THRU FRI.
LARGE SCALE SUBSIDENCE ASSOCIATED WITH SURFACE HIGH EXTENDING
FROM THE GREAT LAKES INTO EASTERN CANADA SHOULD BRING AN END TO
NUISANCE SNOW SHOWER ACTIVITY BY FRI NGT.
CONCERNING THE POTENTIAL WEEKEND STORM...
THERE IS BROAD MODEL CONSENSUS IN A SURFACE LOW DEVELOPING OVER
THE GULF COAST REGION AND TRACKING NORTHEAST OFF THE EAST COAST
THIS WEEKEND. HOWEVER...THERE CONTINUES TO BE A WIDE RANGE OF
POSSIBLE SOLUTIONS WITH ABOVE AVERAGE SPREAD IN THE LOW TRACK.
IN ADDITION TO THE LARGE SPREAD...THERE HAVE BEEN RUN-TO-RUN
[IN]CONSISTENCY ISSUES THAT CONTINUE TO PLAGUE THE MODEL FCSTS
IN PARTICULAR TODAYS 15/12Z RUN OF THE DETERMINISTIC ECMWF WHICH
HAS BACKED OFF ON ITS BULLISH WINTER STORM SCENARIO THAT IT HAS
BEEN ADVERTISING FOR THE PREVIOUS 4 CYCLES. CURIOUSLY BOTH THE
GEFS AND ECENS SEEM TO BE LEANING MORE IN FAVOR OF A LOW TRACK
CLOSER TO THE COAST - WITH A MEAN POSITION WEST OF THEIR
RESPSECTIVE DETERMINISTIC MODEL CORES. WITH THE STORM STILL 5-6
DAYS OUT THERE IS A LOT OF TIME FOR THE FORECAST TO CHANGE.
CONFIDENCE IS LOW REGARDING ANY POTENTIAL DETAILS OR IMPACTS WITH
THIS SYSTEM. HIGH PRESSURE SHOULD BUILD INTO THE AREA EARLY NEXT
WEEK.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
COMPLEX FCST OVERNIGHT INTO TUE...GIVEN THAT SOME AREAS ARE
CLEAR WITH FOG FORMING...OTHERS MAY STAY CLEAR...AND LOW
CLDS STILL IN PLACE ACROSS PORTIONS OF THE AREA.
OTHER CONCERN IS THE FORMATION OF ICE IN AREAS THAT ARE
CLEAR...GIVEN LIGHT WINDS AND HIGH HUMIDITY LEVELS.
06Z TAFS SENT.
EARLIER DISCUSSION BELOW.
SATL IMAGERY SHOWS LOW CLOUDS HAVE CLEARED ACROSS SOUTHERN PA
EARLY THIS EVENING. THIS CLEARING TREND IS EXPECTED TO WORK SLOWLY
NORTHWARD OVERNIGHT...AS INVERSION HGT FALLS. HOWEVER...THE
CLEARING SKY...COMBINED WITH A NEARLY CALM WIND AND LOW DWPT
DEPRESSIONS...WILL LEAD TO AREAS OF FOG OVER THE EASTERN HALF OF
THE STATE. LATEST HRRR OUTPUT SUGGESTS KIPT SOUTH THRU KMDT AND
KLNS STAND THE BEST CHC OF IFR VSBYS LATE TONIGHT. INCREASING
HIGH CLOUDS AND SERLY BREEZE SHOULD LIMIT THE FOG FORMATION AT
KJST. ACROSS THE NW MTNS...MDL SOUNDINGS/SREF OUTPUT SUPPORT
LINGERING IFR CONDS AT KBFD THRU THE NIGHT.
A LOW PRESSURE SYSTEM TRACKING WEST OF PENNSYLVANIA WILL BRING A
PERIOD OF RAIN SHOWERS TUESDAY. SIGNIFICANT REDUCTIONS REMAIN
LIKELY...ESP AT KBFD WHERE MOIST SOUTHERLY FLOW ASCENDING THE MTNS
WILL LIKELY PRODUCE IFR CONDS THRU THE DAY. MAIN PRECIP WILL MOVE
OUT TUE EVE...BUT LIGHT WIND AND LINGERING LOW LVL MOISTURE COULD
RESULT IN REDUCED VSBYS FROM FOG THRU TUE EVENING.
OUTLOOK...
WED...LOW CIGS/SHSNRA LIKELY W MTNS...MAINLY AM.
THU-FRI...NO SIG WX EXPECTED.
SAT...SNOW/REDUCED VSBY POSS SOUTHERN PA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...STEINBUGL
AVIATION...FITZGERALD/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1253 AM EST TUE DEC 16 2014
.SYNOPSIS...
SEASONAL TEMPERATURES WILL RETURN BEHIND A COLD FRONT WHICH WILL
PASS THROUGH ON TUESDAY EVENING. SCATTERED MOUNTAIN SNOW SHOWERS
ARE THEN EXPECTED FOR MID AND LATE WEEK. CONFIDENCE IS LOW
CONCERNING ALL DETAILS AND POTENTIAL IMPACTS ASSOCIATED WITH A LOW
PRESSURE SYSTEM EXPECTED TO TRACK NORTHEAST FROM THE GULF COAST
STATES OFF THE EAST COAST THIS WEEKEND.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
10 PM UPDATE...
TWEAKINGS OF SKY BASED ON RECENT OBS DEPICTING A RELUCTANTLY RECEDING
REGION OF RELATIVELY HIGH RELATIVE HUMIDITY ALOFT. BUT HIGH CLOUDS
ALREADY RIDING OVER THE AREAS WHICH DID CLEAR OUT IN THE LOW
LEVELS. TEMPS DROPPED QUICKLY IN THE CLEAR AND CALM AREAS IN THE
SOUTH...SO SOME TWEAKS TO TEMPS HAVE BEEN MADE AS WELL. MOST MESO
MODELS MEANDER THE MUCH-ANTICIPATED MOISTURE/SHOWERS. SO...A
SLIGHT TWEAK LATER IN TIMING HAS ALSO BEEN MADE.
PREV...
A RIDGE OF HIGH PRESSURE WILL DRIFT OFF THE EAST COAST TONIGHT.
INCREASING SOUTH TO SOUTHWESTERLY FLOW OVER PENN /AT 925 MB AND
850 MB RESPECTIVELY/ WAS HELPING TO ERODE THE SOUTHERN EDGE OF
THE EXTENSIVE STRATUS/STRATOCU ACROSS SCENT PENN AND THE LOWER
SUSQ VALLEY REGION.
LIGHTER WINDS AND BROAD DIFFLUENCE AT BOTH LEVELS ACROSS THE
NORTHERN THIRD TO HALF OF THE STATE WILL HELP TO MAINTAIN THE
LOWER CLOUD DECK THERE THROUGH THE OVERNIGHT HOURS BENEATH CIRRUS
OF VARYING THICKNESS STREAMING NE FROM THE OHIO RIVER VALLEY.
COOLEST TEMPS TONIGHT MAY BE FOUND ACROSS THE SCENT ZONES AND
PORTIONS OF THE LOWER SUSQ VALLEY WHERE MAINLY CLEAR SKIES AND
SLIGHTLY COOLER SFC DEWPOINTS AROUND 32F WILL YIELD LATE EVENING
LOWS IN THE LOWER 30S. TEMPS WILL BE SIMILAR IF NOT A DEG OR 2
HIGHER ACRS THE NRN MTNS...WHERE CLOUDS...SLIGHTLY HIGHER
DEWPOINTS WILL BE FOUND.
THE CENTRAL MTNS AND LAURELS WILL HAVE LOWS 2-4 DEG F HIGHER THAN
ELSEWHERE ACROSS THE NORTH...AND SOUTH.
PRECIP IN THE FORM OF SHOWERS DOESN/T KNOCK ON OUR WESTERN
DOORSTEP UNTIL 10-12Z TUESDAY.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
SHORT RANGE GUIDANCE REMAINS IN VERY GOOD AGREEMENT WITH BRINGING
A WEAKENING LOW PRESSURE AREA AND OCCLUSION/COLD FRONT THROUGH
THE AREA TUESDAY. MODELS DISAGREE A BIT ON PRECIP TOTALS...BUT
WITH IT ALL BEING RAIN IT WON/T MATTER TOO MUCH. AMOUNTS LOOK TO
RANGE FROM A TENTH OR TWO ACROSS THE SE TO A MAX OF MAYBE HALF AN
INCH IN THE NORTH. THOUGH IT WILL BE MILD FOR MID DECEMBER...CLOUDS
AND SHOWERS SHOULD HOLD TEMPS IN THE 40S.
MAIN PRECIP LIFTS NE TUE EVE AS MAIN TROUGH LIFTS OUT. ANOTHER
SHORTWAVE ROTATES IN FROM THE GREAT LAKES QUICKLY BEHIND...TURNING
FLOW W/NW AND PUSHING AN AREA OF SOMEWHAT COLDER AIR BACK INTO PA.
FLOW LOOKS TO ALIGN ENOUGH WITH THE LAKES TO GENERATE SOME SNOW
SHOWERS IN THE NW MTNS...WHICH WILL BRING MAINLY LIGHT
ACCUMS...THOUGH BANDS OF A COUPLE INCHES OF ACCUM IS POSS IN
PORTIONS OF MAINLY NW WARREN COUNTY. OROGRAPHIC FLOW OVER WESTERN
AND NORTHERN HIGHER TERRAIN WILL BRING LIGHT SCT SNOW SHOWERS DOWN
TO A KAOO-KUNV-KIPT LINE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
A RATHER POTENT SHORTWAVE TROUGH WILL PIVOT EASTWARD FROM THE
GREAT LAKES AND CROSS THE AREA WED NGT BEHIND THE DEPARTING
SURFACE LOW LIFTING SLOWLY NORTH FROM MAINE INTO NEW BRUNSWICK
CANADA. A REINFORCING SHOT OF COLD AIR ALOFT SHOULD ACCOMPANY THE
TRAILING SHORTWAVE WHICH MAY ACT TO BRIEFLY ENHANCE POST FRONTAL
LAKE EFFECT AND UPSLOPE SNOW SHOWERS OVER THE WESTERN HIGHLANDS.
ITS NOT OUT OF THE QUESTION THAT THE STRONG VORTMAX COULD INDUCE
SNOW SHOWERS EAST OF THE ALLEGHENY FRONT WED NGT HOWEVER THE
GLOBAL MODEL QPFS ARE NOT IN FAVOR OF THIS OUTCOME. DESPITE A
WELL ALIGNED WNW FLOW AND FAIRLY STRONG LOW LEVEL COLD AIR
ADVECTION...MODEL SOUNDINGS SHOW RATHER SHALLOW MOISTURE/LOW
INVERSION HGTS ALONG WITH DRY AIR WHICH SHOULD LIMIT MAX SNOW
ACCUM POTENTIAL (POTENTIAL FOR THIS MUCH OR WORST CASE) OVER THE
NW MTNS TO 2-3 INCHES BY THU MORNING...WITH AROUND 1 INCH ACCUM
THE MOST LIKELY OUTCOME. OVERALL THE GENERAL WEATHER TREND IN
CENTRAL PA WILL BE TOWARD A BRISK AND COLDER PATTERN WED THRU FRI.
LARGE SCALE SUBSIDENCE ASSOCIATED WITH SURFACE HIGH EXTENDING
FROM THE GREAT LAKES INTO EASTERN CANADA SHOULD BRING AN END TO
NUISANCE SNOW SHOWER ACTIVITY BY FRI NGT.
CONCERNING THE POTENTIAL WEEKEND STORM...
THERE IS BROAD MODEL CONSENSUS IN A SURFACE LOW DEVELOPING OVER
THE GULF COAST REGION AND TRACKING NORTHEAST OFF THE EAST COAST
THIS WEEKEND. HOWEVER...THERE CONTINUES TO BE A WIDE RANGE OF
POSSIBLE SOLUTIONS WITH ABOVE AVERAGE SPREAD IN THE LOW TRACK.
IN ADDITION TO THE LARGE SPREAD...THERE HAVE BEEN RUN-TO-RUN
[IN]CONSISTENCY ISSUES THAT CONTINUE TO PLAGUE THE MODEL FCSTS
IN PARTICULAR TODAYS 15/12Z RUN OF THE DETERMINISTIC ECMWF WHICH
HAS BACKED OFF ON ITS BULLISH WINTER STORM SCENARIO THAT IT HAS
BEEN ADVERTISING FOR THE PREVIOUS 4 CYCLES. CURIOUSLY BOTH THE
GEFS AND ECENS SEEM TO BE LEANING MORE IN FAVOR OF A LOW TRACK
CLOSER TO THE COAST - WITH A MEAN POSITION WEST OF THEIR
RESPSECTIVE DETERMINISTIC MODEL CORES. WITH THE STORM STILL 5-6
DAYS OUT THERE IS A LOT OF TIME FOR THE FORECAST TO CHANGE.
CONFIDENCE IS LOW REGARDING ANY POTENTIAL DETAILS OR IMPACTS WITH
THIS SYSTEM. HIGH PRESSURE SHOULD BUILD INTO THE AREA EARLY NEXT
WEEK.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
COMPLEX FCST OVERNIGHT INTO TUE...GIVEN THAT SOME AREAS ARE
CLEAR WITH FOG FORMING...OTHERS MAY STAY CLEAR...AND LOW
CLDS STILL IN PLACE ACROSS PORTIONS OF THE AREA.
OTHER CONCERN IS THE FORMATION OF ICE IN AREAS THAT ARE
CLEAR...GIVEN LIGHT WINDS AND HIGH HUMIDITY LEVELS.
06Z TAFS SENT.
EARLIER DISCUSSION BELOW.
SATL IMAGERY SHOWS LOW CLOUDS HAVE CLEARED ACROSS SOUTHERN PA
EARLY THIS EVENING. THIS CLEARING TREND IS EXPECTED TO WORK SLOWLY
NORTHWARD OVERNIGHT...AS INVERSION HGT FALLS. HOWEVER...THE
CLEARING SKY...COMBINED WITH A NEARLY CALM WIND AND LOW DWPT
DEPRESSIONS...WILL LEAD TO AREAS OF FOG OVER THE EASTERN HALF OF
THE STATE. LATEST HRRR OUTPUT SUGGESTS KIPT SOUTH THRU KMDT AND
KLNS STAND THE BEST CHC OF IFR VSBYS LATE TONIGHT. INCREASING
HIGH CLOUDS AND SERLY BREEZE SHOULD LIMIT THE FOG FORMATION AT
KJST. ACROSS THE NW MTNS...MDL SOUNDINGS/SREF OUTPUT SUPPORT
LINGERING IFR CONDS AT KBFD THRU THE NIGHT.
A LOW PRESSURE SYSTEM TRACKING WEST OF PENNSYLVANIA WILL BRING A
PERIOD OF RAIN SHOWERS TUESDAY. SIGNIFICANT REDUCTIONS REMAIN
LIKELY...ESP AT KBFD WHERE MOIST SOUTHERLY FLOW ASCENDING THE MTNS
WILL LIKELY PRODUCE IFR CONDS THRU THE DAY. MAIN PRECIP WILL MOVE
OUT TUE EVE...BUT LIGHT WIND AND LINGERING LOW LVL MOISTURE COULD
RESULT IN REDUCED VSBYS FROM FOG THRU TUE EVENING.
OUTLOOK...
WED...LOW CIGS/SHSNRA LIKELY W MTNS...MAINLY AM.
THU-FRI...NO SIG WX EXPECTED.
SAT...SNOW/REDUCED VSBY POSS SOUTHERN PA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT/RXR
NEAR TERM...DANGELO/LAMBERT/RXR
SHORT TERM...
LONG TERM...STEINBUGL
AVIATION...FITZGERALD/MARTIN
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
919 PM MST MON DEC 15 2014
.SHORT TERM...THIS EVENING THROUGH TUESDAY NIGHT
ISSUED AT 213 PM MST MON DEC 15 2014
UPPER LEVEL ANALYSIS HAS LOW CENTER OVER IOWA SLIDING NORTHEAST.
UPPER RIDGE IS SLOWLY BUILDING ACROSS THE ROCKIES AS EAST PACIFIC
TROF APPROACHES THE WEST COAST. SKIES ACROSS THE NORTHERN PLAINS
RANGE FROM MOSTLY SUNNY OVER WESTERN AREAS...TO CLOUDY WITH LIGHT
SNOW FROM THE CENTRAL DAKOTAS EAST. AT THE SURFACE...CANADIAN
HIGH PRESSURE CONTINUES TO SLIDE SOUTH INTO THE AREA. NORTHWEST
WINDS CONTINUE TO BE QUITE BREEZY...WITH WINDS JUST BEGINNING TO
SLACKEN ACROSS NORTHEAST WYOMING. TEMPERATURES AT 2 PM ARE IN THE
20S.
TONIGHT...DRY AIR MOVES IN QUICKLY TONIGHT BEHIND THE EXITING
SYSTEM...AND PRECIP WILL END ACROSS SOUTH CENTRAL SOUTH DAKOTA BY
EARLY EVENING. HOWEVER...SOME AREAS OF CLOUDS AND SOME PATCHY FOG
WILL STICK AROUND THROUGH THE NIGHT. WITH MAINLY PARTLY CLOUDY
CONDITIONS OVERNIGHT...LOW TEMPERATURES WILL FALL INTO THE SINGLE
DIGITS AND TEENS.
TUESDAY...WESTERN UPPER RIDGE WILL CROSS THE NORTHERN PLAINS AS
THE CANADIAN SURFACE HIGH SHIFTS INTO THE EASTERN DAKOTAS. NORTH
WINDS WILL BE LIGHT...AND SLOWLY SHIFT AROUND OUT OF THE SOUTH BY
LATE AFTERNOON. HIGHS WILL BE IN THE 20S TO LOWER 30S...WITH LOWS
TUESDAY NIGHT AROUND 10 TO 20. SKIES WILL BECOME CLOUDIER
OVERNIGHT AHEAD OF AN APPROACHING UPPER TROUGH.
.LONG TERM...WEDNESDAY THROUGH MONDAY
ISSUED AT 213 PM MST MON DEC 15 2014
PROGRESSIVE SPLIT FLOW PATTERN TO PERSIST THROUGH THE LONG TERM
PERIOD. MAINLY DRY WX EXPECTED THROUGH THE PERIOD GIVEN TROUGH RE-
LOADING IN THE WESTERN CONUS. HOWEVER...ANOTHER STRONG SOUTHERN
PERIPHERY UPPER TROUGH WILL EJECT OUT OF THE SW CONUS IN THE THU-
FRI PERIOD. FORECAST MODELS ARE NOW LATCHING ONTO THE EJECTION OF
A PRIMARY FRONT SIDE IMPULSE. THIS SYSTEM WOULD BRING A SMALL
CHANCE FOR LIGHT SNOW ACROSS THE FAR NW FA WED AS IT INTERACTS
WITH THE LL BAROCLINIC ZONE IN PLACE. THIS SYSTEM IS PRESENT IN
ALL FORECAST MODELS ALTHOUGH THE TRACK IS STILL IN QUESTION.
INCLUDED A LOW POP ACROSS THE NW WED FOR THIS. THE MAIN SW CONUS
UPPER TROUGH CONTINUES TO BE ADVERTISED TO TRACK JUST SOUTH OF THE
FA TOWARD THE END OF THE WEEK. IF ANY NORTHERN STREAM IMPULSES
TEND TO PHASE WITH THIS SYSTEM...A TRACK FARTHER NW COULD STILL BE
POSSIBLE...WHICH COULD BRING SOME CHANCES FOR SNOW TO SCENTRAL
AREAS ONCE AGAIN TOWARD FRIDAY-SAT. TENDENCIES FOR ANOTHER STRONG
WESTERN NOAM RIDGE REMAIN PRESENT IN MEAN ENSEMBLES AND
DETERMINISTIC SOLUTIONS PER ANOTHER EXTENSION OF THE EAST ASIAN
UPPER JET. THIS COULD SPELL MUCH WARMER CONDITIONS FOR THE
FOLLOWING WEEK IF THE RIDGE BIASES EAST AS IT HAS IN THIS PATTERN.
HOWEVER...CURRENT LONG RANGE ECMWF/GFS RUNS STILL SUPPORT A CLOSED
LOW IN THE PACIFIC NEAR HAWAII WITH A DOMINATE NORTHERN
STREAM...UNCHARACTERISTIC OF THE CURRENT REGIME. THE 12Z ECMWF HAS
NOW SHIFTED THE RIDGE SLIGHTLY NE WITH THE BAROCLINIC ZONE RIGHT
ON TOP OF THE FA. THIS HEIGHT PATTERN LOOKS VERY SIMILAR TO THE
THANKSGIVING DAY PATTERN 7-10 DAYS OUT WITH A LARGE RANGE IN TEMPS
AMONG DETERMINISTIC SOLUTIONS MID NEXT WEEK.
GIVEN STRONGER PROGRESSIVE TENDENCIES...FORECAST MODELS SUPPORT
WARMER WESTERLY FLOW INTO THE REGION A LITTLE EARLIER THAN BEFORE.
HENCE...HAVE WARMED TEMPS SOME IN THE LATTER PORTION OF THE PERIOD.
OTHERWISE...NO OTHER SIG CHANGES TO THE FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 911 PM MST MON DEC 15 2014
WIDESPREAD MVFR/LOCAL IFR CONDS INTO TUE AFTERNOON. MVFR CIGS
WILL REMAIN THROUGH MUCH OF THE PERIOD. FURTHER WEST...CLEAR SKIES
WILL LIKELY REMAIN OVER THE BLACK HILLS. HOWEVER...MVFR CIGS ARE
EXPECTED TO STRADDLE THE RAP TERMINAL GIVEN MOIST NW
FLOW...CONFIRMED IN HIRES GUIDANCE. THERE IS THE POTENTIAL FOR
PARTIAL CLEARING AT THE RAP TERMINAL. HOWEVER...HIGHEST
CONFIDENCE IS IN CONTINUED MVFR CIGS. LOW CIGS OVER THE WY PLAINS
WILL LIKELY LINGER INTO LATE TUE MORNING UNTIL DRY LL SOUTHERLY
FLOW CAN BECOME ESTABLISHED. SOME PATCHY FOG IS ALSO POSSIBLE
THERE. RAP MODEL INDICATES POTENTIAL CLEARING EARLIER...HOWEVER
CONFIDENCE IN THIS REMAINS LOW GIVEN HIRES GUIDANCE. WILL KEEP
WITH IFR CIGS ATTM MONITORING TRENDS FOR POTENTIAL AMENDMENTS.
CIGS WILL BE DIFFICULT LATE IN THE PERIOD TUE AFTERNOON AS THE SFC
RIDGE AXIS WILL BE OVER THE FA. THIS WILL LIKELY HINDER STRATUS
MIX OUT WITH MANY PLACES LIKELY SEEING AT LEAST MVFR CIGS THROUGH
MUCH OF TUE.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...15
LONG TERM...JC
AVIATION...JC
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
322 PM CST TUE DEC 16 2014
.DISCUSSION...
A COMPLEX AND PROGRESSIVE UPPER LEVEL PATTERN WILL PREVAIL OVER
THE U.S. INTO EARLY NEXT WEEK. TUESDAY AFTERNOON/S GOES WATER
VAPOR IMAGERY SHOWED TWO UPPER LOWS OFF THE WEST COAST... WITH
SIGNIFICANT UPPER LEVEL UPSTREAM POLAR JET ENERGY OVER THE EASTERN
NORTH PACIFIC. FURTHER SOUTH...A MOISTURE LADEN SUBTROPICAL UPPER
LEVEL JET EXTENDED FROM THE EASTERN PACIFIC...ACROSS NORTHERN
MEXICO... INTO THE SOUTHERN PLAINS.
THIS EVENING SHOULD SEE CONTINUED DISSIPATION OF LOW STRATUS OVER
NORTHERN PORTIONS OF THE MIDSOUTH...FOLLOWED BY INCREASING HIGH
CLOUDS FROM THE SUBTROPICAL JET. BY WEDNESDAY AFTERNOON... AN
EMBEDDED SHORTWAVE WILL LIFT OUT OF THE SOUTHERN ROCKIES AND
DEAMPLIFY DOWNSTREAM OVER THE LOWER AND MIDDLE MS RIVER VALLEY. A
DRY SUBCLOUD LAYER /BELOW 12KFT/ WILL TAKE TIME TO SATURATE...
FINALLY DOING SO LATE WEDNESDAY NIGHT. NORTHERN PORTIONS OF THE
MIDSOUTH MAY SEE LIGHT SNOW OR SLIGHT MIXING IN WITH LIGHT RAIN
TOWARD THURSDAY MORNING. GIVEN ONLY WEAK WARM ADVECTION ALOFT
CONTRIBUTING TO LIFT...PRECIP AMOUNTS ACROSS THE MIDSOUTH SHOULD
BE LIGHT.
THE NEXT PRECIP EVENT APPEARS ON TRACK FOR FRIDAY AFTERNOON
THROUGH SATURDAY MORNING. THIS SYSTEM WILL BE BETTER ORGANIZED
THAN THE WEDNESDAY NIGHT SYSTEM...GIVEN THAT IT WILL PHASE WITH
NORTHERN BRANCH ENERGY. 12Z GFS AND 12Z ECMWF HAVE SETTLED ON THE
SOLUTION ORIGINALLY ADVERTISED BY THE GFS A FEW DAYS AGO. HEAVIER
CONVECTIVE RAINS WILL BE LIKELY OVER NORTH MS AND POINTS SOUTH
FRIDAY NIGHT... WHILE LIGHTER RAIN MAY MIX WITH LIGHT SNOW AT
TIMES FROM NORTHEAST AR INTO NORTHWEST TN BY SATURDAY MORNING.
THIS SYSTEM QUICKLY LIFT OUT...LEAVING SATURDAY AFTERNOON AND
EVENING WITH DRY CONDITIONS...BUT POSSIBLY SLOW TO DISSIPATE
POST FRONTAL CLOUDINESS.
DISPARITIES BETWEEN TODAY/S 12Z GFS AND ECMWF SOLUTIONS BEGIN TO
AMPLIFY...LEADING TO REDUCED FORECAST CONFIDENCE TOWARD THE
CHRISTMAS HOLIDAY. BOTH MODELS DEPICT ADDITIONAL ENERGY COMING
ONSHORE OVER THE WESTERN U.S...BUT DIFFER ON TIMING AND DOWNSTREAM
EVOLUTION ACROSS THE REMAINDER OF THE LOWER 48.
PWB
&&
.AVIATION...
18Z TAF CYCLE
MAIN FORECAST ISSUE THIS TAF CYCLE WILL BE MVFR CIGS ON SW PERIPHERY
OF MIDWEST/GREAT LAKES SYSTEM. LATEST HIGH-RES MODELS SUGGEST CIGS
CLEARING KJBR BY AROUND 22Z...WITH TEMPO MVFR CIGS AT KMEM THRU
AROUND 22Z. HRRR IS QUICKER WITH TIMING THAN RAP...SO WILL DO A BIT
OF BLENDING ON THE TIMING. CIGS SHOULD HOLD AT KMKL WELL INTO THE
NIGHT. FORECAST SURFACE RH SUGGESTS POSSIBILITY OF MIST/FOG AT
KMEM...WILL HINT AT IT IN TAF AND MONITOR TRENDS/LATER GUIDANCE.
WINDS WILL GRADUALLY DECREASE AND VEER TO NLY/NNELY AS SURFACE RIDGE
SETTLES INTO AREA.
GW
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1146 AM CST TUE DEC 16 2014
.DISCUSSION...
UPDATED FOR 18Z AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 319 AM CST TUE DEC 16 2014/
CLOUDS ARE SPREADING SOUTH ACROSS THE FORECAST AREA EARLY THIS
MORNING WITH TEMPERATURES MAINLY IN THE 40S. THESE CLOUDS ARE
ASSOCIATED WITH AN UPPER LEVEL LOW CURRENTLY MOVING ACROSS CENTRAL
ILLINOIS. AS THE LOW MOVES EAST TODAY THE CLOUDS WILL EVENTUALLY
MOVE OUT OF THE REGION BUT MOST OF THE DAY SHOULD BE FAIRLY
CLOUDY. BECAUSE OF THE CLOUD COVER TEMPERATURES WILL NOT WARM UP
TOO MUCH TODAY WITH HIGHS IN THE UPPER 40S TO LOWER 50S.
AS SKIES CLEAR TONIGHT...TEMPERATURES WILL BE COLDER THAN THEY
HAVE BEEN FOR THE LAST COUPLE OF DAYS WITH LOWS WEDNESDAY MORNING
IN THE UPPER 20S TO LOWER 30S. HIGH PRESSURE WILL REMAIN OVER THE
REGION ON WEDNESDAY KEEPING THINGS DRY AND UNSEASONABLY COOL WITH
HIGHS IN THE LOWER 40S TO AROUND 50 DEGREES.
BY WEDNESDAY NIGHT LOW PRESSURE WILL BE OVER WEST TEXAS AND WITH
SOUTH WINDS OVER THE REGION MOISTURE WILL INCREASE ACROSS THE
FORECAST AREA. THIS WILL PRODUCE SOME LIGHT PRECIPITATION MAINLY
IN THE FORM OF RAIN WITH SOME LIGHT SNOW POSSIBLE OVER NORTHERN
SECTIONS OF THE FORECAST AREA AS TEMPERATURES APPROACH THE
FREEZING MARK BY THURSDAY MORNING. SOME LIGHT PRECIPITATION WILL
CONTINUE INTO THURSDAY WITH SOME LIGHT SNOW POSSIBLE THURSDAY
MORNING OVER NORTHERN SECTIONS OF FORECAST AREA.
ANOTHER DISTURBANCE WILL APPROACH THE REGION THURSDAY NIGHT
BRINGING MORE PRECIPITATION MAINLY OVER SOUTHWEST SECTIONS OF THE
FORECAST AREA. BY FRIDAY...LOW PRESSURE WILL BE OVER SOUTHEAST
TEXAS AND WILL TRACK ACROSS THE GULF COAST STATES REACHING
SOUTHEAST ALABAMA BY SATURDAY MORNING. THIS SYSTEM WILL BRING MORE
PRECIPITATION TO THE REGION MAINLY IN THE FORM OF RAIN FRIDAY AND
FRIDAY NIGHT BUT SOME LIGHT SNOW WILL BE POSSIBLE OVER PORTIONS OF
NORTHEAST ARKANSAS AND THE MISSOURI BOOTHEEL LATE FRIDAY NIGHT AND
EARLY SATURDAY MORNING. AS THE LOW CONTINUES TO MOVE EAST ON
SATURDAY RAIN WILL BE ENDING.
HIGH PRESSURE WILL BUILD BACK INTO THE REGION SATURDAY NIGHT
BRINGING A PERIOD OF DRY WEATHER FOR SATURDAY NIGHT THROUGH
MONDAY. TEMPERATURES WILL BE NEAR OR SLIGHTLY BELOW NORMAL LEVELS
DURING THIS PERIOD.
ARS
&&
.AVIATION...
18Z TAF CYCLE
MAIN FORECAST ISSUE THIS TAF CYCLE WILL BE MVFR CIGS ON SW PERIPHERY
OF MIDWEST/GREAT LAKES SYSTEM. LATEST HIGH-RES MODELS SUGGEST CIGS
CLEARING KJBR BY AROUND 22Z...WITH TEMPO MVFR CIGS AT KMEM THRU
AROUND 22Z. HRRR IS QUICKER WITH TIMING THAN RAP...SO WILL DO A BIT
OF BLENDING ON THE TIMING. CIGS SHOULD HOLD AT KMKL WELL INTO THE
NIGHT. FORECAST SURFACE RH SUGGESTS POSSIBILITY OF MIST/FOG AT
KMEM...WILL HINT AT IT IN TAF AND MONITOR TRENDS/LATER GUIDANCE.
WINDS WILL GRADUALLY DECREASE AND VEER TO NLY/NNELY AS SURFACE RIDGE
SETTLES INTO AREA.
GW
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
313 PM CST TUE DEC 16 2014
.DISCUSSION...
THE BEST DAY OF THE WEEK WEATHER-WISE AS THE MAJORITY OF THE REGION
IS UNDER CLEAR SKIES...AFTERNOON TEMPERATURE READINGS WARMING INTO
THE SEASONABLE LOWER TO MIDDLE 60S UNDER A LIGHT NORTH WIND. AS
THE 1030 MB SURFACE HIGH...CURRENTLY CENTERED OVER THE CENTRAL RED
RIVER VALLEY...TRAVELS NORTHEAST OVER THE NEXT 24 HOURS WINDS WILL
VEER MORE EASTERLY TO EVENTUAL SOUTHEASTERLY WEDNESDAY NIGHT. THIS
WILL AID IN DRAWING UP MORE MOISTURE RICH AIR INTO THE FORECAST AREA.
GREATER THAN 50% LOW TO MID LEVEL RH VALUES ARE CURRENTLY BEING PROGGED
BY THE GFS AND NAM TO ADVANCE UPON THE WESTERN COUNTIES THROUGH THE
EARLY MORNING HOURS. THIS WILL BE THE FLY IN THE OINTMENT THAT REGULATES
WESTERN CWA MINIMUM TEMPERATURES...CLOUDS WILL KEEP MINS TO THE MID
40S WITH SLOW-ADVANCING CLOUDS FROM THE WEST ALLOWING THESE SITES
TO FALL BELOW 40F. HAVE SPLIT THE DIFFERENCE AND WENT WITH THE AVERAGE
LOWER 40S OUT WEST...MIDDLE 40S ELSEWHERE OVER THE INTERIOR...CLEARER
SKIES OVER THE LAKE LIVINGSTON AREA WILL AFFORD THE UPPER 30S.
A WARM AIR ADVECTION PATTERN SETS UP WEDNESDAY THROUGH THURSDAY THAT
WILL GRADUALLY DETERIORATE CONDITIONS FROM WEST TO EAST. INCREASING
OVERCAST THROUGH WEDNESDAY AFTERNOON WILL LEAD TO EITHER DRIZZLE
OR VERY LIGHT RAIN SHOWERS FORMING OVER THE WEST CENTRAL ZONES AND
ADVANCING EASTWARD THROUGH THE OVERNIGHT EARLY THURSDAY MORNING
HOURS. AS OVERNIGHT TEMPERATURES FALL INTO THE LOWER TO MIDDLE 50S
THIS WILL CLOSE THE DEW POINT DEPRESSION ENOUGH TO SATURATE THE
LOWER LEVELS...LOWERING CLOUDS BASES AND INTRODUCING FOG WITHIN
LIGHT PRECIPITATION. A MURKY THURSDAY MORNING WILL BE THE PRECURSOR
TO AN OVERCAST DAY WITH HIGH PROBS OF SCATTERED SHOWERS WITH
ISOLATED THUNDER AS A WEAK SURFACE BOUNDARY HANGS UP OVER THE CWA.
EASTERN TEXAS MIGHT ALSO FALL UNDER THE RR QUAD OF A PRONOUNCED
JET JUST DOWNSTREAM OF THE NEXT MAJOR WEATHER MAKER FRIDAY.
THIS FEATURE BEING A WESTERN LONG WAVE TROUGH THAT WILL PASS OVER
THE REGION DURING THE DAY FRIDAY...INCREASING AREAWIDE POPS TO
LIKELY FOR SHOWERS AND STORMS. AS OF NOW...THE GFS AND ECMWF
SOLUTIONS DEVELOP A COASTAL TROUGH OR CLOSED OFF LOW THAT WOULD
MAKE FOR A MORE ACTIVE DAY...QPF RANGING FROM AROUND A HALF OF AN
INCH AROUND THE COAST TO SLIGHTLY OVER TWO INCHES OVER OUR NORTHERN
ZONES. ALL DEPENDENT UPON THE POSITIONING OF THE UPPER TROUGH
AND/OR APPENDANT SURFACE TROF/LOW ON WHERE THE HIGHEST RAIN
FALLS...BUT NWP PROGS AND WPC DO PLACE THE HIGHEST DAY 3 RAINFALL
OVER THE NORTHERN HALF OF THE FORECAST AREA. AGGRESSIVE COLD
FRONTAL PASSAGE SATURDAY WILL WHISK ALL CONVECTION EAST BY SUNRISE
SATURDAY. THE BACKING SURFACE HIGH WILL ELONGATE BACK INTO THE
REGION FROM THE MIDWESTERN U.S. AND PRODUCE A PERSISTENT NE-E
FLOW THROUGH EARLY CHRISTMAS WEEK. THE CHRISTMAS DAY OUTLOOK HAS
LOWERING WESTERN TEXAS PRESSURES MAINTAINING A LIGHT TO MODERATE
ONSHORE FLOW...LOW RAIN CHANCES WITH SEASONABLE TEMPERATURE TRENDS.
31
&&
.MARINE...
HIGH PRESSURE WILL BUILD INTO THE SOUTHERN PLAINS THIS EVENING AND
WINDS WILL SUBSIDE AND GENTLY VEER TO THE NE AS THE HIGH DRIFTS
EAST. ONSHORE WINDS ARE EXPECTED TO RETURN WEDNESDAY AFTERNOON AS
THE HIGH MOVES FURTHER EAST. ONSHORE WINDS WILL PERSIST THROUGH
FRIDAY MORNING AS LOW PRESSURE DEVELOPS OVER SOUTH TEXAS AND
SCOOTS UP THE COAST ON FRIDAY AFTERNOON. A COLD FRONT WILL CROSS
THE COAST FRIDAY EVENING AND STRONG OFFSHORE WINDS WILL DEVELOP IN
THE WAKE OF THE FRONT. A SMALL CRAFT ADVISORY MAY BE REQUIRED FRI
NIGHT INTO SATURDAY. WINDS WILL BEGIN TO RELAX BY SAT EVENING AS
HIGH PRESSURE SETTLES OVER THE CENTRAL PLAINS. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 43 54 52 65 57 / 0 40 50 30 80
HOUSTON (IAH) 44 59 55 70 60 / 0 20 50 50 60
GALVESTON (GLS) 53 62 61 69 63 / 0 20 40 40 50
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 3 PM CST THIS
AFTERNOON FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO
THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS
FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...31/43
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
505 AM CST TUE DEC 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 216 AM CST TUE DEC 16 2014
MAIN FOCUS IS THE CURRENT PRECIPITATION AND TEMPERATURE TRENDS WITH
THE PASSING SYSTEM. LOOKING AT RADAR LOOPS...THERE ARE ACTUALLY
TWO DISTINCT CIRCULATIONS SHOWN...WITH THE MAIN SWIRL OVER IL...
AND ANOTHER JUST WEST OF GREEN BAY. MAIN DEFORMATION BAND WITH THE
SOUTHERN SWIRL FROM NORTHEAST IA INTO CENTRAL WI. NORTHERN
DEFORMATION BAND FROM SOUTH CENTRAL MN UP INTO THE ARROWHEAD AND
NORTHWEST WI. WARM TEMPERATURES HAVE KEPT PRECIPITATION ALL LIQUID
UP THROUGH 1 AM...BUT A MIX WAS SUGGESTED BY SURFACE OBS AND LAPS
TEMPERATURE FIELDS TO BE JUST MOVING INTO OUR AREA OF SOUTHEAST
MN. THANKFULLY...THE MAIN PUNCH OF THIS COMPLEX STORM SYSTEM IS
ALREADY BEGINNING TO PULL AWAY...SO WITH ONLY LIMITED AMOUNTS OF
PRECIP LEFT TO FALL...DO NOT ANTICIPATE ANY SIGNIFICANT
ACCUMULATION OF SNOW OR ICY MIX. ONLY THREAT FOR AN ACCUMULATION
LOOKS TO BE OVER THE FAR NORTHERN COUNTIES OF OUR SERVICE AREA.
GUSTY NORTHWEST WINDS BEHIND THE FRONT WITH SUSTAINED WINDS IN THE
20-30 MPH RANGE...AND GUSTS UP NEAR 40 MPH. ACCOMPANIED BY FALLING
TEMPS TODAY...EXPECT RAW WIND CHILLS IN THE TEENS TODAY AND SINGLE
DIGITS TONIGHT BEFORE WIND SPEEDS SUBSIDE.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 216 AM CST TUE DEC 16 2014
ANOTHER LONG WAVE TROUGH WAS DROPPING QUICKLY SOUTHEAST ACROSS
MANITOBA THIS MORNING...AND THIS WILL END UP MERGING WITH OUR
CURRENT CLOSED CIRCULATION AS THE WHOLE CONGLOMERATION WOBBLES
AROUND THE GREAT LAKES TODAY THROUGH WEDNESDAY. WITH SOME LIFT
GENERATED BY THIS SECOND WAVE...AND WITH CONTINUED COLD AIR
ARRIVING TO HELP SQUEEZE OUT ANY REMAINING MOISTURE FROM THE
BOUNDARY LAYER...ANTICIPATE SOME FLURRIES WILL BE SEEN TONIGHT
GENERALLY NORTH OF I-90...AND INTO WEDNESDAY MAINLY NORTH OF I-94.
HIGH PRESSURE BUILDS INTO THE UPPER MIDWEST FOR THURSDAY...AND
LOOKS TO HANG AROUND ALL THE WAY THROUGH THE WEEKEND. THE UPPER
LEVEL FLOW PATTERN REMAINS VERY BLOCKED ACROSS NORTH AMERICA...
WITH THE MAIN STORM TRACKS WELL SOUTH AND WELL NORTH OF OUR
GENERAL AREA. AS A RESULT...ANTICIPATE BENIGN WEATHER WITH NO
PRECIPITATION AND TEMPERATURES NEAR SEASONAL NORMS.
THE PATTERN DOES APPEAR TO TRANSITION TO MORE ACTIVE ZONAL FLOW AS
WE GET INTO NEXT WEEK...BUT THERE ARE SEVERAL DISCREPANCIES IN THE
VARIOUS MODEL OUTPUTS AS TO WHAT THAT MEANS FOR OUR AREA.
BUT...FOR THE SNOW LOVERS OUT THERE...DO NOT GIVE UP ON A WHITE
CHRISTMAS JUST YET...
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 505 AM CST TUE DEC 16 2014
RADAR AND OBSERVATIONS INDICATE THE BULK OF THE PRECIPITATION HAS
ALREADY MOVED BY BOTH TAF SITES THIS MORNING. STILL A LITTLE BIT
OF WRAP AROUND LIGHT SNOW OVER EASTERN MINNESOTA THAT THE 16.08Z
HRRR SUGGESTS COULD COME ACROSS THIS MORNING AND PRODUCE A PERIOD
OF MVFR VISIBILITIES. OTHERWISE...THE 16.09Z RAP AND 16.06Z NAM
SUGGEST THAT CEILINGS WILL NOT BUDGE TODAY OR TONIGHT IN THE
CYCLONIC FLOW THAT WILL PERSIST BEHIND THE SURFACE LOW. BASED ON
THIS...HAVE KEPT THE CEILINGS AT BOTH SITES MVFR THROUGH THE
ENTIRE PERIOD. THE NORTHWEST WINDS WILL REMAIN GUSTY THROUGH THE
DAY WITH KRST HITTING 30 KNOTS AT TIMES BEFORE THESE WINDS START
TO DIMINISH LATE IN THE AFTERNOON. THE GOOD LOW LEVEL LAPSE RATES
REMAIN IN PLACE INTO THE EVENING...SO HAVE KEPT SOME GUSTS GOING
PAST SUNSET.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...MW
LONG TERM...MW
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
228 PM MST TUE DEC 16 2014
.UPDATE...
ISSUED AT 225 PM MST TUE DEC 16 2014
ONE FINAL AFTERNOON GRIDDED FORECAST AND ZONE FORECAST UPDATE
TO ACCOUNT FOR MAXIMUM TEMPERATURES...WHICH VARY GREATLY DEPENDING
ON CLOUD COVER AND RESIDUAL SNOWPACK...WITH 2 PM TEMPERATURES IN
THE LOWER 30S AT RAWLINS...LARAMIE AND CHEYENNE...AND TEMPERATURES
ONLY IN THE UPPER TEENS TO UPPER 20S AT DOUGLAS...TORRINGTON...
CHADRON...SCOTTSBLUFF...ALLIANCE...KIMBALL AND SIDNEY.
UPDATE ISSUED AT 1018 AM MST TUE DEC 16 2014
OUR MIDNIGHT SHIFT TEAM HAD THE FOG WELL COVERED AT TORRINGTON...
SCOTTSBLUFF AND ALLIANCE...AND ALONG THE NORTH PLATTE RIVER
VALLEY. EVEN AT 10 AM...VISIBILITIES IN FOG WERE STILL ONLY
ONE QUARTER OF A MILE AT ALLIANCE...ONE HALF MILE AT SCOTTSBLUFF
AND OVER TWO MILES AT TORRINGTON. EXTENDED FOG FOR A FEW HOURS
IN OUR GRIDDED FORECASTS.
FOR OUR AFTERNOON FORECAST...NEGATIVELY TILTED SHORTWAVE TROUGH
ALOFT MOVES NORTHEAST ACROSS EASTERN IDAHO...NORTHERN UTAH AND
WESTERN WYOMING...WITH THE 12Z NAM SPREADING LIGHT SNOW ACROSS
MUCH OF CARBON AND ALBANY COUNTIES...THUS HAVE ADJUSTED OUR
POPS AND SNOW COVERAGE GRIDS THERE TO MATCH EXPECTED SNOW
COVERAGE. ALSO ADJUSTED OUR MAXIMUM TEMPERATURES THIS AFTERNOON
AS WITH CLOUD COVER AND SNOWFIELD...TEMPERATURES WILL STRUGGLE
TO CLIMB ABOVE FREEZING AT SOME LOCATIONS ESPECIALLY ALONG THE
NORTH PLATTE RIVER VALLEY. ADJUSTED DEWPOINTS AND CLOUD COVER TO
MATCH TRENDS.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY NIGHT)
ISSUED AT 330 AM MST TUE DEC 16 2014
CHILLY NIGHT ACROSS THE REGION ESPECIALLY FOR THOSE AREAS IN THE
SOUTHERN NEBRASKA PANHANDLE WHERE SKIES ARE CLEAR AND WIDESPREAD
SNOW IS ON THE GROUND. TEMPERATURES IN THE NORTHERN PANHANDLE ARE
ABOUT 10 DEGREES WARMER DUE TO THE LOW CLOUDS AND PATCHY FOG. ALSO
GETTING FOG IN THE NORTH PLATTE RIVER VALLEY FROM DOUGLAS TO
TORRINGTON WITH REALLY LIGHT WINDS. THE HRRR SUGGESTS THAT THE LOW
CLOUDS WILL BE QUITE PERSISTENT OVER THE PANHANDLE THROUGH LATE
MORNING. GENERALLY QUIET WEATHER OVER THE NEXT FEW DAYS WITH WEAK
SFC PRESSURE GRADIENTS AND A LACK OF IMPACTFUL WEATHER SYSTEMS.
THE MODELS SHOW A SHORTWAVE TROUGH MOVING FROM THE GREAT BASIN
INTO WESTERN WY THIS AFTN INTO TONIGHT. IR IMAGERY CURRENTLY SHOWS
QUITE A BIT OF MIDLVL MOISTURE STREAMING NORTHEASTWARD INTO
COLORADO. THIS MOISTURE WILL PUSH ACROSS THE REGION BY THIS AFTN.
INCREASED POPS A BIT FOR THE SIERRA MADRE AND SNOWY RANGES FOR THE
AFTN...HOWEVER ONLY EXPECTING A FEW INCHES AT MOST. HIGH
TEMPERATURES WILL BE AROUND NORMAL OVER THE NEXT FEW DAYS
(GENERALLY IN THE MID-TO-UPPER 30S)...WHICH MEANS THAT SNOW COVER
FROM THE RECENT STORM WILL BE SLOW TO MELT.
SYNOPTIC PATTERN DOES NOT CHANGE A WHOLE LOT THROUGH THURSDAY.
SIMILAR TO THE LAST FEW WEEKS...THE UPPER LEVEL JET WILL BE REMAIN
ACROSS THE SOUTHWESTERN UNITED STATES WITH WEAK FLOW ALOFT OVER
WY. NO WIND CONCERNS AS THE CAG-CPR GRADIENT NEVER GETS ABOVE 20
METERS. A SFC HIGH OVER THE NORTHERN PLAINS WILL MAINTAIN SOUTH TO
SOUTHEAST WINDS OVER THE NEBRASKA PANHANDLE THROUGH WED NIGHT. THE
NAM AND SREF SHOW THE POTENTIAL FOR LOW CLOUD FORMATION TONIGHT
AND MORE SO ON WED NIGHT. THE MODELS HAVE BEEN CONSISTENT AT
SHOWING MUCH OF THE MOISTURE AND DYNAMICS ASSOCIATED WITH AN UPPER
LEVEL WAVE REMAINING SOUTH OF THE CWA ON WED AND WED NIGHT. KEPT
SLIGHT CHANCE POPS OVER THE SIERRA MADRE AND SNOWY RANGES...WITH
THE BEST CHANCES OF SNOW OVER COLORADO.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 330 AM MST TUE DEC 16 2014
SEASONAL AND A RELATIVELY TRANQUIL PERIOD THROUGH THE UPCOMING
WEEKEND. WARMER AND BREEZY TO LOCALLY WINDY CONDITIONS RETURN
EARLY NEXT WEEK. PERSISTENT NORTHWEST FLOW WILL BE IN PLACE FRIDAY
THRU SUNDAY WITH PERIODIC EMBEDDED SHORTWAVES PASSING OVER THE
REGION. LIGHT MOUNTAIN SNOW WILL BE A POSSIBILITY THRU THE PERIOD
ALONG WITH PERIODIC BOUTS OF CLOUD-COVER ELSEWHERE...THICKEST NEAR
SHORTWAVE ENERGY. SEE LITTLE MOVEMENT IN TEMPERATURES DURING THIS
PERIOD AS WELL AS NORTHWEST FLOW KEEP ADVECTION NEUTRAL. SO HIGHS
IN THE LOW 30S WEST OF THE LARAMIE RANGE AND 30S TO NR 40 EAST CAN
BE EXPECTED.
WINDS WILL STRENGTHEN FOR MONDAY/TUESDAY AS THE NOSE OF 150+ KNOT H3
JET STREAK APPROACHES AND MOVES OVERHEAD. ALTHOUGH TIMING
DIFFERENCES EXIST IN WHEN THE LLVL GRADIENT IS THE STRONGEST...BOTH
ARE SIMILAR IN PROGGING 50-60 KNOTS AT H7 FOR MONDAY AND TUESDAY. IF
SUBSEQUENT MODEL OUTPUT CONTINUES...THIS WOULD BE ENOUGH FOR THE
POSSIBILITY OF THE NEXT HIGH WIND EVENT MAINLY FOR WIND PRONE
AREAS. CHANNELED VORT ENERGY WILL ALSO PROVIDE CHANCES FOR SNOW
SHOWERS MONDAY AND TUESDAY AS WELL. MODELS AGAIN HAVE TIMING
DIFFERENCES DURING THIS PERIOD...SO FOR NOW JUST INTRODUCED SOME
LIGHT SNOW CHANCES DURING THIS PERIOD. DOWNSLOPE COMPONENT WILL
BOOST HIGH TEMPS MONDAY/TUESDAY INTO THE MID/UPPER 30S WEST AND
LOW/MID 40S OUT ON THE ERN PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1113 AM MST TUE DEC 16 2014
FOG/LOW STRATUS PERSISTS MAINLY IN THE NORTH PLATTE RIVER VALLEY
AND NEAR KCDR THIS MORNING...WITH VFR CONDITIONS ELSEWHERE. LIFTED
CIGS/VSBYS AROUND 20/21Z FOR THESE SITES ALTHO NOT CONFIDENT
CONDITIONS WILL IMPROVE MUCH BEFORE DROPPING ONCE AGAIN LATER THIS
EVENING. STILL EXPECT -SHSN EARLY THIS AFTERNOON AT THE WYO
SITES...WITH IFR CIGS/VSBYS EXPECTED AT KRWL IN MOIST SOUTHEAST
FLOW AFTER 05Z THIS EVENING. WINDS OVERALL WILL REMAIN RELATIVELY
LIGHT...EXCEPT NEAR KRWL WHERE GUSTS OF 20 TO 25 KTS ARE POSSIBLE
THIS AFTERNOON.
&&
.FIRE WEATHER...
ISSUED AT 330 AM MST TUE DEC 16 2014
NO FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. COLD TEMPERATURES
WILL KEEP SNOW COVER ON THE GROUND ACROSS MUCH OF THE REGION.
AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 50 PERCENT AND
WINDS WILL BE LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...RUBIN
SHORT TERM...ZF
LONG TERM...CAH
AVIATION...RJM
FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1113 AM MST TUE DEC 16 2014
.UPDATE...
ISSUED AT 1018 AM MST TUE DEC 16 2014
OUR MIDNIGHT SHIFT TEAM HAD THE FOG WELL COVERED AT TORRINGTON...
SCOTTSBLUFF AND ALLIANCE...AND ALONG THE NORTH PLATTE RIVER
VALLEY. EVEN AT 10 AM...VISIBILITIES IN FOG WERE STILL ONLY
ONE QUARTER OF A MILE AT ALLIANCE...ONE HALF MILE AT SCOTTSBLUFF
AND OVER TWO MILES AT TORRINGTON. EXTENDED FOG FOR A FEW HOURS
IN OUR GRIDDED FORECASTS.
FOR OUR AFTERNOON FORECAST...NEGATIVELY TILTED SHORTWAVE TROUGH
ALOFT MOVES NORTHEAST ACROSS EASTERN IDAHO...NORTHERN UTAH AND
WESTERN WYOMING...WITH THE 12Z NAM SPREADING LIGHT SNOW ACROSS
MUCH OF CARBON AND ALBANY COUNTIES...THUS HAVE ADJUSTED OUR
POPS AND SNOW COVERAGE GRIDS THERE TO MATCH EXPECTED SNOW
COVERAGE. ALSO ADJUSTED OUR MAXIMUM TEMPERATURES THIS AFTERNOON
AS WITH CLOUD COVER AND SNOWFIELD...TEMPERATURES WILL STRUGGLE
TO CLIMB ABOVE FREEZING AT SOME LOCATIONS ESPECIALLY ALONG THE
NORTH PLATTE RIVER VALLEY. ADJUSTED DEWPOINTS AND CLOUD COVER TO
MATCH TRENDS.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY NIGHT)
ISSUED AT 330 AM MST TUE DEC 16 2014
CHILLY NIGHT ACROSS THE REGION ESPECIALLY FOR THOSE AREAS IN THE
SOUTHERN NEBRASKA PANHANDLE WHERE SKIES ARE CLEAR AND WIDESPREAD
SNOW IS ON THE GROUND. TEMPERATURES IN THE NORTHERN PANHANDLE ARE
ABOUT 10 DEGREES WARMER DUE TO THE LOW CLOUDS AND PATCHY FOG. ALSO
GETTING FOG IN THE NORTH PLATTE RIVER VALLEY FROM DOUGLAS TO
TORRINGTON WITH REALLY LIGHT WINDS. THE HRRR SUGGESTS THAT THE LOW
CLOUDS WILL BE QUITE PERSISTENT OVER THE PANHANDLE THROUGH LATE
MORNING. GENERALLY QUIET WEATHER OVER THE NEXT FEW DAYS WITH WEAK
SFC PRESSURE GRADIENTS AND A LACK OF IMPACTFUL WEATHER SYSTEMS.
THE MODELS SHOW A SHORTWAVE TROUGH MOVING FROM THE GREAT BASIN
INTO WESTERN WY THIS AFTN INTO TONIGHT. IR IMAGERY CURRENTLY SHOWS
QUITE A BIT OF MIDLVL MOISTURE STREAMING NORTHEASTWARD INTO
COLORADO. THIS MOISTURE WILL PUSH ACROSS THE REGION BY THIS AFTN.
INCREASED POPS A BIT FOR THE SIERRA MADRE AND SNOWY RANGES FOR THE
AFTN...HOWEVER ONLY EXPECTING A FEW INCHES AT MOST. HIGH
TEMPERATURES WILL BE AROUND NORMAL OVER THE NEXT FEW DAYS
(GENERALLY IN THE MID-TO-UPPER 30S)...WHICH MEANS THAT SNOW COVER
FROM THE RECENT STORM WILL BE SLOW TO MELT.
SYNOPTIC PATTERN DOES NOT CHANGE A WHOLE LOT THROUGH THURSDAY.
SIMILAR TO THE LAST FEW WEEKS...THE UPPER LEVEL JET WILL BE REMAIN
ACROSS THE SOUTHWESTERN UNITED STATES WITH WEAK FLOW ALOFT OVER
WY. NO WIND CONCERNS AS THE CAG-CPR GRADIENT NEVER GETS ABOVE 20
METERS. A SFC HIGH OVER THE NORTHERN PLAINS WILL MAINTAIN SOUTH TO
SOUTHEAST WINDS OVER THE NEBRASKA PANHANDLE THROUGH WED NIGHT. THE
NAM AND SREF SHOW THE POTENTIAL FOR LOW CLOUD FORMATION TONIGHT
AND MORE SO ON WED NIGHT. THE MODELS HAVE BEEN CONSISTENT AT
SHOWING MUCH OF THE MOISTURE AND DYNAMICS ASSOCIATED WITH AN UPPER
LEVEL WAVE REMAINING SOUTH OF THE CWA ON WED AND WED NIGHT. KEPT
SLIGHT CHANCE POPS OVER THE SIERRA MADRE AND SNOWY RANGES...WITH
THE BEST CHANCES OF SNOW OVER COLORADO.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 330 AM MST TUE DEC 16 2014
SEASONAL AND A RELATIVELY TRANQUIL PERIOD THROUGH THE UPCOMING
WEEKEND. WARMER AND BREEZY TO LOCALLY WINDY CONDITIONS RETURN
EARLY NEXT WEEK. PERSISTENT NORTHWEST FLOW WILL BE IN PLACE FRIDAY
THRU SUNDAY WITH PERIODIC EMBEDDED SHORTWAVES PASSING OVER THE
REGION. LIGHT MOUNTAIN SNOW WILL BE A POSSIBILITY THRU THE PERIOD
ALONG WITH PERIODIC BOUTS OF CLOUD-COVER ELSEWHERE...THICKEST NEAR
SHORTWAVE ENERGY. SEE LITTLE MOVEMENT IN TEMPERATURES DURING THIS
PERIOD AS WELL AS NORTHWEST FLOW KEEP ADVECTION NEUTRAL. SO HIGHS
IN THE LOW 30S WEST OF THE LARAMIE RANGE AND 30S TO NR 40 EAST CAN
BE EXPECTED.
WINDS WILL STRENGTHEN FOR MONDAY/TUESDAY AS THE NOSE OF 150+ KNOT H3
JET STREAK APPROACHES AND MOVES OVERHEAD. ALTHOUGH TIMING
DIFFERENCES EXIST IN WHEN THE LLVL GRADIENT IS THE STRONGEST...BOTH
ARE SIMILAR IN PROGGING 50-60 KNOTS AT H7 FOR MONDAY AND TUESDAY. IF
SUBSEQUENT MODEL OUTPUT CONTINUES...THIS WOULD BE ENOUGH FOR THE
POSSIBILITY OF THE NEXT HIGH WIND EVENT MAINLY FOR WIND PRONE
AREAS. CHANNELED VORT ENERGY WILL ALSO PROVIDE CHANCES FOR SNOW
SHOWERS MONDAY AND TUESDAY AS WELL. MODELS AGAIN HAVE TIMING
DIFFERENCES DURING THIS PERIOD...SO FOR NOW JUST INTRODUCED SOME
LIGHT SNOW CHANCES DURING THIS PERIOD. DOWNSLOPE COMPONENT WILL
BOOST HIGH TEMPS MONDAY/TUESDAY INTO THE MID/UPPER 30S WEST AND
LOW/MID 40S OUT ON THE ERN PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1113 AM MST TUE DEC 16 2014
FOG/LOW STRATUS PERSISTS MAINLY IN THE NORTH PLATTE RIVER VALLEY
AND NEAR KCDR THIS MORNING...WITH VFR CONDITIONS ELSEWHERE. LIFTED
CIGS/VSBYS AROUND 20/21Z FOR THESE SITES ALTHO NOT CONFIDENT
CONDITIONS WILL IMPROVE MUCH BEFORE DROPPING ONCE AGAIN LATER THIS
EVENING. STILL EXPECT -SHSN EARLY THIS AFTERNOON AT THE WYO
SITES...WITH IFR CIGS/VSBYS EXPECTED AT KRWL IN MOIST SOUTHEAST
FLOW AFTER 05Z THIS EVENING. WINDS OVERALL WILL REMAIN RELATIVELY
LIGHT...EXCEPT NEAR KRWL WHERE GUSTS OF 20 TO 25 KTS ARE POSSIBLE
THIS AFTERNOON.
&&
.FIRE WEATHER...
ISSUED AT 330 AM MST TUE DEC 16 2014
NO FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. COLD TEMPERATURES
WILL KEEP SNOW COVER ON THE GROUND ACROSS MUCH OF THE REGION.
AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 50 PERCENT AND
WINDS WILL BE LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...RUBIN
SHORT TERM...ZF
LONG TERM...CAH
AVIATION...RJM
FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1033 AM MST TUE DEC 16 2014
.UPDATE...
ISSUED AT 1018 AM MST TUE DEC 16 2014
OUR MIDNIGHT SHIFT TEAM HAD THE FOG WELL COVERED AT TORRINGTON...
SCOTTSBLUFF AND ALLIANCE...AND ALONG THE NORTH PLATTE RIVER
VALLEY. EVEN AT 10 AM...VISIBILITIES IN FOG WERE STILL ONLY
ONE QUARTER OF A MILE AT ALLIANCE...ONE HALF MILE AT SCOTTSBLUFF
AND OVER TWO MILES AT TORRINGTON. EXTENDED FOG FOR A FEW HOURS
IN OUR GRIDDED FORECASTS.
FOR OUR AFTERNOON FORECAST...NEGATIVELY TILTED SHORTWAVE TROUGH
ALOFT MOVES NORTHEAST ACROSS EASTERN IDAHO...NORTHERN UTAH AND
WESTERN WYOMING...WITH THE 12Z NAM SPREADING LIGHT SNOW ACROSS
MUCH OF CARBON AND ALBANY COUNTIES...THUS HAVE ADJUSTED OUR
POPS AND SNOW COVERAGE GRIDS THERE TO MATCH EXPECTED SNOW
COVERAGE. ALSO ADJUSTED OUR MAXIMUM TEMPERATURES THIS AFTERNOON
AS WITH CLOUD COVER AND SNOWFIELD...TEMPERATURES WILL STRUGGLE
TO CLIMB ABOVE FREEZING AT SOME LOCATIONS ESPECIALLY ALONG THE
NORTH PLATTE RIVER VALLEY. ADJUSTED DEWPOINTS AND CLOUD COVER TO
MATCH TRENDS.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY NIGHT)
ISSUED AT 330 AM MST TUE DEC 16 2014
CHILLY NIGHT ACROSS THE REGION ESPECIALLY FOR THOSE AREAS IN THE
SOUTHERN NEBRASKA PANHANDLE WHERE SKIES ARE CLEAR AND WIDESPREAD
SNOW IS ON THE GROUND. TEMPERATURES IN THE NORTHERN PANHANDLE ARE
ABOUT 10 DEGREES WARMER DUE TO THE LOW CLOUDS AND PATCHY FOG. ALSO
GETTING FOG IN THE NORTH PLATTE RIVER VALLEY FROM DOUGLAS TO
TORRINGTON WITH REALLY LIGHT WINDS. THE HRRR SUGGESTS THAT THE LOW
CLOUDS WILL BE QUITE PERSISTENT OVER THE PANHANDLE THROUGH LATE
MORNING. GENERALLY QUIET WEATHER OVER THE NEXT FEW DAYS WITH WEAK
SFC PRESSURE GRADIENTS AND A LACK OF IMPACTFUL WEATHER SYSTEMS.
THE MODELS SHOW A SHORTWAVE TROUGH MOVING FROM THE GREAT BASIN
INTO WESTERN WY THIS AFTN INTO TONIGHT. IR IMAGERY CURRENTLY SHOWS
QUITE A BIT OF MIDLVL MOISTURE STREAMING NORTHEASTWARD INTO
COLORADO. THIS MOISTURE WILL PUSH ACROSS THE REGION BY THIS AFTN.
INCREASED POPS A BIT FOR THE SIERRA MADRE AND SNOWY RANGES FOR THE
AFTN...HOWEVER ONLY EXPECTING A FEW INCHES AT MOST. HIGH
TEMPERATURES WILL BE AROUND NORMAL OVER THE NEXT FEW DAYS
(GENERALLY IN THE MID-TO-UPPER 30S)...WHICH MEANS THAT SNOW COVER
FROM THE RECENT STORM WILL BE SLOW TO MELT.
SYNOPTIC PATTERN DOES NOT CHANGE A WHOLE LOT THROUGH THURSDAY.
SIMILAR TO THE LAST FEW WEEKS...THE UPPER LEVEL JET WILL BE REMAIN
ACROSS THE SOUTHWESTERN UNITED STATES WITH WEAK FLOW ALOFT OVER
WY. NO WIND CONCERNS AS THE CAG-CPR GRADIENT NEVER GETS ABOVE 20
METERS. A SFC HIGH OVER THE NORTHERN PLAINS WILL MAINTAIN SOUTH TO
SOUTHEAST WINDS OVER THE NEBRASKA PANHANDLE THROUGH WED NIGHT. THE
NAM AND SREF SHOW THE POTENTIAL FOR LOW CLOUD FORMATION TONIGHT
AND MORE SO ON WED NIGHT. THE MODELS HAVE BEEN CONSISTENT AT
SHOWING MUCH OF THE MOISTURE AND DYNAMICS ASSOCIATED WITH AN UPPER
LEVEL WAVE REMAINING SOUTH OF THE CWA ON WED AND WED NIGHT. KEPT
SLIGHT CHANCE POPS OVER THE SIERRA MADRE AND SNOWY RANGES...WITH
THE BEST CHANCES OF SNOW OVER COLORADO.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 330 AM MST TUE DEC 16 2014
SEASONAL AND A RELATIVELY TRANQUIL PERIOD THROUGH THE UPCOMING
WEEKEND. WARMER AND BREEZY TO LOCALLY WINDY CONDITIONS RETURN
EARLY NEXT WEEK. PERSISTENT NORTHWEST FLOW WILL BE IN PLACE FRIDAY
THRU SUNDAY WITH PERIODIC EMBEDDED SHORTWAVES PASSING OVER THE
REGION. LIGHT MOUNTAIN SNOW WILL BE A POSSIBILITY THRU THE PERIOD
ALONG WITH PERIODIC BOUTS OF CLOUD-COVER ELSEWHERE...THICKEST NEAR
SHORTWAVE ENERGY. SEE LITTLE MOVEMENT IN TEMPERATURES DURING THIS
PERIOD AS WELL AS NORTHWEST FLOW KEEP ADVECTION NEUTRAL. SO HIGHS
IN THE LOW 30S WEST OF THE LARAMIE RANGE AND 30S TO NR 40 EAST CAN
BE EXPECTED.
WINDS WILL STRENGTHEN FOR MONDAY/TUESDAY AS THE NOSE OF 150+ KNOT H3
JET STREAK APPROACHES AND MOVES OVERHEAD. ALTHOUGH TIMING
DIFFERENCES EXIST IN WHEN THE LLVL GRADIENT IS THE STRONGEST...BOTH
ARE SIMILAR IN PROGGING 50-60 KNOTS AT H7 FOR MONDAY AND TUESDAY. IF
SUBSEQUENT MODEL OUTPUT CONTINUES...THIS WOULD BE ENOUGH FOR THE
POSSIBILITY OF THE NEXT HIGH WIND EVENT MAINLY FOR WIND PRONE
AREAS. CHANNELED VORT ENERGY WILL ALSO PROVIDE CHANCES FOR SNOW
SHOWERS MONDAY AND TUESDAY AS WELL. MODELS AGAIN HAVE TIMING
DIFFERENCES DURING THIS PERIOD...SO FOR NOW JUST INTRODUCED SOME
LIGHT SNOW CHANCES DURING THIS PERIOD. DOWNSLOPE COMPONENT WILL
BOOST HIGH TEMPS MONDAY/TUESDAY INTO THE MID/UPPER 30S WEST AND
LOW/MID 40S OUT ON THE ERN PLAINS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY NIGHT)
ISSUED AT 330 AM MST TUE DEC 16 2014
SE WYOMING TERMINALS...VFR CONDITIONS TO PREVAIL AT TERMINALS THIS
MORNING WITH A DRIER AIR MASS OVERHEAD. -SHSN AND MVFR CIGS WILL
RETURN TODAY 18-24Z. WINDS WILL BE SOUTHWEST AT 5 TO 10 KNOTS WITH
LOCALLY HIGHER GUSTS IN THE VICINITY OF KRWL. VFR CONDITIONS RETURN
AFTER 00Z.
WRN NEBRASKA TERMINALS...MAIN CHALLENGE THIS MORNING IS WITH ONGOING
FOG/LOW STRATUS. IFR/LIFR CIGS AND VISIBILITIES WILL CONTINUE AT
MOST WRN NEBRASKA TERMINALS THRU AROUND 18Z...AT WHICH TIME SHOULD
IMPROVE TO MVFR OR EVEN VFR AT KBFF AND KSNY. TIMING OF LIFTING IS
ALWAYS DIFFICULT IN THESE CASES...THOUGH IT LOOKS LIKE KCDR WILL SEE
THE BEST OPPORTUNITY FOR FOG TO HANG IN THE LONGEST TODAY. SHOULD
SEE CONDITIONS SLOWLY IMPROVE BY MIDDAY AND ESPECIALLY DURING THE
AFTERNOON HOURS.
&&
.FIRE WEATHER...
ISSUED AT 330 AM MST TUE DEC 16 2014
NO FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. COLD TEMPERATURES
WILL KEEP SNOW COVER ON THE GROUND ACROSS MUCH OF THE REGION.
AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 50 PERCENT AND
WINDS WILL BE LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...RUBIN
SHORT TERM...ZF
LONG TERM...CAH
AVIATION...CAH
FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
345 AM MST TUE DEC 16 2014
.SHORT TERM...(TODAY THROUGH THURSDAY NIGHT)
ISSUED AT 330 AM MST TUE DEC 16 2014
CHILLY NIGHT ACROSS THE REGION ESPECIALLY FOR THOSE AREAS IN THE
SOUTHERN NEBRASKA PANHANDLE WHERE SKIES ARE CLEAR AND WIDESPREAD
SNOW IS ON THE GROUND. TEMPERATURES IN THE NORTHERN PANHANDLE ARE
ABOUT 10 DEGREES WARMER DUE TO THE LOW CLOUDS AND PATCHY FOG. ALSO
GETTING FOG IN THE NORTH PLATTE RIVER VALLEY FROM DOUGLAS TO
TORRINGTON WITH REALLY LIGHT WINDS. THE HRRR SUGGESTS THAT THE LOW
CLOUDS WILL BE QUITE PERSISTENT OVER THE PANHANDLE THROUGH LATE
MORNING. GENERALLY QUIET WEATHER OVER THE NEXT FEW DAYS WITH WEAK
SFC PRESSURE GRADIENTS AND A LACK OF IMPACTFUL WEATHER SYSTEMS.
THE MODELS SHOW A SHORTWAVE TROUGH MOVING FROM THE GREAT BASIN
INTO WESTERN WY THIS AFTN INTO TONIGHT. IR IMAGERY CURRENTLY SHOWS
QUITE A BIT OF MIDLVL MOISTURE STREAMING NORTHEASTWARD INTO
COLORADO. THIS MOISTURE WILL PUSH ACROSS THE REGION BY THIS AFTN.
INCREASED POPS A BIT FOR THE SIERRA MADRE AND SNOWY RANGES FOR THE
AFTN...HOWEVER ONLY EXPECTING A FEW INCHES AT MOST. HIGH
TEMPERATURES WILL BE AROUND NORMAL OVER THE NEXT FEW DAYS
(GENERALLY IN THE MID-TO-UPPER 30S)...WHICH MEANS THAT SNOW COVER
FROM THE RECENT STORM WILL BE SLOW TO MELT.
SYNOPTIC PATTERN DOES NOT CHANGE A WHOLE LOT THROUGH THURSDAY.
SIMILAR TO THE LAST FEW WEEKS...THE UPPER LEVEL JET WILL BE REMAIN
ACROSS THE SOUTHWESTERN UNITED STATES WITH WEAK FLOW ALOFT OVER
WY. NO WIND CONCERNS AS THE CAG-CPR GRADIENT NEVER GETS ABOVE 20
METERS. A SFC HIGH OVER THE NORTHERN PLAINS WILL MAINTAIN SOUTH TO
SOUTHEAST WINDS OVER THE NEBRASKA PANHANDLE THROUGH WED NIGHT. THE
NAM AND SREF SHOW THE POTENTIAL FOR LOW CLOUD FORMATION TONIGHT
AND MORE SO ON WED NIGHT. THE MODELS HAVE BEEN CONSISTENT AT
SHOWING MUCH OF THE MOISTURE AND DYNAMICS ASSOCIATED WITH AN UPPER
LEVEL WAVE REMAINING SOUTH OF THE CWA ON WED AND WED NIGHT. KEPT
SLIGHT CHANCE POPS OVER THE SIERRA MADRE AND SNOWY RANGES...WITH
THE BEST CHANCES OF SNOW OVER COLORADO.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 330 AM MST TUE DEC 16 2014
SEASONAL AND A RELATIVELY TRANQUIL PERIOD THROUGH THE UPCOMING
WEEKEND. WARMER AND BREEZY TO LOCALLY WINDY CONDITIONS RETURN
EARLY NEXT WEEK. PERSISTENT NORTHWEST FLOW WILL BE IN PLACE FRIDAY
THRU SUNDAY WITH PERIODIC EMBEDDED SHORTWAVES PASSING OVER THE
REGION. LIGHT MOUNTAIN SNOW WILL BE A POSSIBILITY THRU THE PERIOD
ALONG WITH PERIODIC BOUTS OF CLOUD-COVER ELSEWHERE...THICKEST NEAR
SHORTWAVE ENERGY. SEE LITTLE MOVEMENT IN TEMPERATURES DURING THIS
PERIOD AS WELL AS NORTHWEST FLOW KEEP ADVECTION NEUTRAL. SO HIGHS
IN THE LOW 30S WEST OF THE LARAMIE RANGE AND 30S TO NR 40 EAST CAN
BE EXPECTED.
WINDS WILL STRENGTHEN FOR MONDAY/TUESDAY AS THE NOSE OF 150+ KNOT H3
JET STREAK APPROACHES AND MOVES OVERHEAD. ALTHOUGH TIMING
DIFFERENCES EXIST IN WHEN THE LLVL GRADIENT IS THE STRONGEST...BOTH
ARE SIMILAR IN PROGGING 50-60 KNOTS AT H7 FOR MONDAY AND TUESDAY. IF
SUBSEQUENT MODEL OUTPUT CONTINUES...THIS WOULD BE ENOUGH FOR THE
POSSIBILITY OF THE NEXT HIGH WIND EVENT MAINLY FOR WIND PRONE
AREAS. CHANNELED VORT ENERGY WILL ALSO PROVIDE CHANCES FOR SNOW
SHOWERS MONDAY AND TUESDAY AS WELL. MODELS AGAIN HAVE TIMING
DIFFERENCES DURING THIS PERIOD...SO FOR NOW JUST INTRODUCED SOME
LIGHT SNOW CHANCES DURING THIS PERIOD. DOWNSLOPE COMPONENT WILL
BOOST HIGH TEMPS MONDAY/TUESDAY INTO THE MID/UPPER 30S WEST AND
LOW/MID 40S OUT ON THE ERN PLAINS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY NIGHT)
ISSUED AT 330 AM MST TUE DEC 16 2014
SE WYOMING TERMINALS...VFR CONDITIONS TO PREVAIL AT TERMINALS THIS
MORNING WITH A DRIER AIR MASS OVERHEAD. -SHSN AND MVFR CIGS WILL
RETURN TODAY 18-24Z. WINDS WILL BE SOUTHWEST AT 5 TO 10 KNOTS WITH
LOCALLY HIGHER GUSTS IN THE VICINITY OF KRWL. VFR CONDITIONS RETURN
AFTER 00Z.
WRN NEBRASKA TERMINALS...MAIN CHALLENGE THIS MORNING IS WITH ONGOING
FOG/LOW STRATUS. IFR/LIFR CIGS AND VISIBILITIES WILL CONTINUE AT
MOST WRN NEBRASKA TERMINALS THRU AROUND 18Z...AT WHICH TIME SHOULD
IMPROVE TO MVFR OR EVEN VFR AT KBFF AND KSNY. TIMING OF LIFTING IS
ALWAYS DIFFICULT IN THESE CASES...THOUGH IT LOOKS LIKE KCDR WILL SEE
THE BEST OPPORTUNITY FOR FOG TO HANG IN THE LONGEST TODAY. SHOULD
SEE CONDITIONS SLOWLY IMPROVE BY MIDDAY AND ESPECIALLY DURING THE
AFTERNOON HOURS.
&&
.FIRE WEATHER...
ISSUED AT 330 AM MST TUE DEC 16 2014
NO FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. COLD TEMPERATURES
WILL KEEP SNOW COVER ON THE GROUND ACROSS MUCH OF THE REGION.
AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 50 PERCENT AND
WINDS WILL BE LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...ZF
LONG TERM...CAH
AVIATION...CAH
FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1037 PM MST MON DEC 15 2014
.UPDATE...
ISSUED AT 815 PM MST MON DEC 15 2014
VERY TRICKY TEMPERATURE FORECAST FOR TONIGHT. LATEST FOG/STRATUS
SATELLITE LOOP AND AIRPORT OBSERVATIONS SHOW A LLVL STRATUS DECK
DRAPED FROM EAST CENTRAL WY SOUTHEASTWARD TOWARD ALLIANCE IN THE
NEBRASKA PANHANDLE. UPSTREAM SFC OBS AND HIGH-RES MODELS WOULD
SUGGEST BLYR MOISTURE WILL REMAIN HIGH FOR MUCH OF THE OVERNIGHT
PERIOD VIA LIGHT NORTHWEST WINDS. LATEST RUNS OF THE HRRR HANG ON
TO THE STRATUS THROUGH SUNRISE TUE. SO DESPITE SEVERAL INCHES OF
FRESH SNOW...THIS WILL HAVE AN IMPACT ON TEMPS. OPTED TO RAISE
LOWS A FEW DEGREES. DID NOT GO AS HIGH AS THE HRRR/RAP YET IN CASE
CLOUDS ACTUALLY DO CLEAR OUT. COULD SEE SOME PATCHY FOG WITH THE
ENHANCED NEAR-SFC MOISTURE...ESPECIALLY OVER THE WESTERN NEBRASKA
PANHANDLE. WILL CONTINUE TO MONITOR TRENDS THROUGH THE EVENING FOR
ANY ADDITIONAL UPDATES.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 335 PM MST MON DEC 15 2014
MID AFTERNOON WATER VAPOR IMAGERY SHOWED THE STACKED LOW PRESSURE
SYSTEM THAT BROUGHT HEAVY SNOW AND GUSTY NORTHWEST WINDS TO THE
HIGH PLAINS WAS TRACKING EAST ACROSS THE MISSOURI VALLEY.
REGIONAL RADAR...SURFACE OBSERVATIONS AND HIGHWAY WEB CAMS
REVEALED SLOWLY IMPROVING CONDITIONS ACROSS THE WESTERN NEBRASKA
PANHANDLE. RECENTLY CANCELLED THE WINTER STORM WARNING AND WEATHER
ADVISORY THAT WAS IN EFFECT UNTIL 3 PM. GUSTY NORTHWEST WINDS OF
25 TO 35 MPH WILL DECREASE LATER THIS AFTERNOON AND EARLY EVENING.
SNOW HAS TAPERED OFF TO FLURRIES OVER THE SOUTHERN NEBRASKA
PANHANDLE. TEMPERATURES WILL CHILLY WITH READINGS IN THE 20S AND
30S...AND WIND CHILLS IN THE SINGLE DIGITS AND TEENS.
LATEST NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE LARGE
SCALE PATTERN. THE STORM SYSTEM OVER THE MIDWEST WILL CONTINUE ITS
EASTWARD TREK ACROSS OHIO VALLEY INTO NEW ENGLAND TUESDAY...WITH A
SECONDARY PIECE OF ENERGY ROTATING THROUGH THE GREAT LAKES. MEANWHILE...
A SHORTWAVE RIDGE WILL SLIDE EAST ACROSS THE FRONT RANGE AND HIGH
PLAINS THROUGH TUESDAY NIGHT...AS THE NEXT PACIFIC TROUGH MOVES
THROUGH THE SOUTHERN GREAT BASIN AND FOUR CORNERS REGION WEDNESDAY.
A WEAKER PRESSURE GRADIENT WILL RESULT IN LIGHTER WINDS DURING THE
SHORT TERM.
WITH PARTIAL CLEARING...LIGHT WINDS AND MOIST BOUNDARY LAYER ACROSS
THE HIGH PLAINS...CONCERN WILL BE PATCHY FOG DEVELOPMENT WITH
STRENGTHENING LOW LEVEL INVERSION. DUE TO FRESH SNOW
PACK...TRENDED CLOSER TO THE COLDER MAVMOS FOR MIN TEMPERATURES
TONIGHT...WITH WIDESPREAD SINGLE DIGITS FOR THE HIGH PLAINS AND
VALLEYS OF SOUTHEAST WY. A FEW LOCATIONS IN THE WESTERN PANHANDLE
COULD DROP TO AROUND 0 DEGREES. THERE WILL BE ENOUGH OF A WESTERLY
WIND COMPONENT TO KEEP TEMPERATURES IN THE LOWER TEENS ELSEWHERE.
INCREASING MID/UPPER LEVEL MOISTURE WILL SPREAD FROM SOUTHWEST TO
NORTHEAST TUESDAY WITH THE APPROACH AND PASSAGE OF THE RIDGE.
THERE WILL BE SOME MOISTURE AND WEAK UPSLOPE FOR LIGHT SNOW OVER
THE SOUTHERN MOUNTAINS. HIGH TEMPERATURES TUESDAY WILL SLIGHTLY
BELOW SEASONAL NORMALS WITH 20S AND 30S. TUESDAY NIGHT WILL NOT BE
AS COLD WITH A MORE SOUTHWESTERLY WIND COMPONENT AND CLOUD COVER
KEEPING MIN TEMPERATURES MOSTLY IN THE TEENS TO AROUND 20. SOME
UPPER SINGLE DIGITS WILL BE POSSIBLE FOR PORTIONS OF THE WESTERN
PANHANDLE. WEDNESDAY WILL BE A CARBON COPY OF TUESDAY WITH MOSTLY
CLOUDY SKIES...COOL TEMPERATURES AND LIGHT OROGRAPHIC SNOWFALL FOR
THE SOUTHERN MOUNTAINS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 258 PM MST MON DEC 15 2014
WEDNESDAY NIGHT/THURSDAY...RATHER MOIST WESTERLY FLOW ALOFT WILL
CONTINUE THE SCATTERED SNOW SHOWERS OVER OUR SNOWY AND SIERRA MADRE
RANGES...DRY ELSEWHERE.
FRIDAY...PRIMARY SHORTWAVE TROUGH ALOFT MOVES ACROSS OUR COUNTIES
WITH DECREASING COVERAGE OF SHOWERS IN THE AFTERNOON...THOUGH IT
WILL BE BREEZY TO WINDY PER PROGGED LOW AND MID LEVEL GRADIENTS.
SATURDAY...CONTINUED BREEZY TO WINDY PER PROGGED LOW AND MID LEVEL
GRADIENTS. SHOULD BE DRY WITH LIMITED LOW AND MID LEVEL MOISTURE AND
LIFT...THOUGH WITH PERIODS OF MIDDLE AND HIGH CLOUDS.
SUNDAY...WINDY PERIOD DEVELOPS WITH STRONG NORTHWEST FLOW ALOFT AND
PROGGED LOW AND MID LEVEL GRADIENTS INCREASING
MONDAY...EVEN WINDIER AS THE PROGGED LOW AND MID LEVEL GRADIENTS
INCREASE SIGNIFICANTLY WITH NORTHWEST FLOW ALOFT. LOOKS LIKE ENOUGH
MID LEVEL MOISTURE FOR SCATTERED OROGRAPHIC SNOW SHOWERS OVER THE
SNOWY AND SIERRA MADRE RANGES...DRY ELSEWHERE. SEASONABLE
TEMPERATURES...THOUGH STILL QUITE WINDY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1027 PM MST MON DEC 15 2014
LOW STRATUS OVER EAST CENTRAL WYOMING AND THE NORTHERN NEBRASKA
PANHANDLE WILL CONTINUE TO RESULT IN MVFR CIGS AT KCDR AND KAIA
OVERNIGHT. AMPLE NEAR-SURFACE MOISTURE FROM FRESH SNOWPACK WILL
CREATE THE POTENTIAL FOR IFR VSBYS IN FOG OVER NORTHERN PORTIONS
OF THE PANHANDLE THROUGH AT LEAST 15Z TUE. BRIEF MVFR/IFR CONDS
WILL BE POSSIBLE OVER SOUTHEAST WY WITH SNOW SHOWERS BETWEEN 18Z
TUE AND 00Z WED. WINDS WILL GENERALLY BE LIGHT.
&&
.FIRE WEATHER...
ISSUED AT 300 PM MST MON DEC 15 2014
NO CONCERNS ANTICIPATED THROUGH MID WEEK WITH WIDESPREAD SNOW
COVER...COOL TEMPERATURES...LIGHTER WINDS AND HIGH RELATIVE
HUMIDITIES.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...CLH
SHORT TERM...MJ
LONG TERM...SAR
AVIATION...CLH
FIRE WEATHER...MJ
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
410 AM EST THU DEC 18 2014
.SYNOPSIS...STRONG MID AND UPPER LEVEL TROUGH IS LOCATED OVER THE
WRN U.S. WITH DOWNSTREAM UPPER LEVEL JET LOCATED ACROSS TX TO THE TN
VALLEY. WEAK MID TO UPPER LEVEL RIDGE ACROSS OUR FORECAST AREA WITH
UPPER LEVEL DISTURBANCES AND JET HELPING TO SPREADING AN OCNL
BROKEN-OVERCAST CIRRUS CLOUDS OVERHEAD. SFC HIGH PRES CENTRAL PLAINS
TO CENTRAL GULF COAST WITH LIGHT W TO NW FLOW OVER OUR AREA. TEMPS
ARE IN THE 40S MOST LOCATIONS WITH A FEW UPPER 30S OVER INLAND SE
GA. PATCHY FOG NOTED OVER THE SUWANNEE VALLEY PER SFC OBS AS PASSING
HIGH CLOUDS ARE MASKING ANY LOW CLOUD OR FOG DETECTION. FOG IS ALSO
INDICATED IN LATEST HRRR AND NARRE FCST GUIDANCE FROM AROUND LIVE
OAK TO OCALA. WILL CONTINUE MENTION OF FOG INTO THE EARLY MORNING
FCST...AND VSBY MAY BE BELOW 1 MI AT TIMES.
.SHORT TERM...FOR TODAY...ONE MID AND UPPER LEVEL SHORTWAVE TROUGH
WILL SHIFT EWD FROM CENTRAL PLAINS TO THE OHIO VALLEY WHILE
DE-AMPLIFYING. WE ANTICIPATE HIGH CLOUDS TO CONTINUE TO AFFECT THE
REGION THROUGH FIRST OF THE HALF OF THE DAY...WITH THINNING OF
CLOUDS IN THE AFTN FROM THE NW TO SE. SFC HIGH PRES NW OF THE AREA
WILL ALLOW FOR PREVAILING LIGHT NW TO N WINDS. MAX TEMPS TODAY
EXPECTED TO BE IN THE 60S AREA-WIDE BUT PERHAPS A TOUCH BELOW
CLIMATOLOGY. TONIGHT...A MORE SIGNIFICANT MID AND UPPER LEVEL SHORTWAVE
LOCATED ACROSS THE FOUR CORNERS WILL TRANSLATE TO LOWER CONUS
GENERATING SFC CYCLOGENESIS OVER THE WRN GULF. THIS DIGGING
SHORTWAVE TROUGH WILL ENHANCE MOISTURE OVER THE AREA LATER TONIGHT
THROUGH FRIDAY WITH PWATS INCREASING FROM ABOUT HALF AN INCH TO 3/4
OF AN INCH. GUIDANCE TEMPS ARE IN GOOD AGREEMENT WITH SIMILAR
READINGS TO THIS MORNING...MAINLY IN UPPER 30S TO LOWER 40S. COOLEST
READINGS WELL INTERIOR LOCATIONS. LOCAL TOOLS AND MODEL SOUNDINGS
DON`T SUPPORT MENTION OF FOG ATTM.
FRIDAY...STRONG MID AND UPPER SHORTWAVE TROUGH WILL MOVE INTO THE MS
RIVER VALLEY AND ASSOCD SFC LOW PRES WILL MOVE TOWARD THE LA COAST.
SFC HIGH PRES DUE N OF THE AREA WILL OOZE EWD ALLOWING WINDS TO
SLOWLY TURN TO THE NELY BUT LIGHT WIND SPEEDS. THE TAIL END OF A
WEAK FRONT WILL MOVE THROUGH PARTS OF SE GA BUT LITTLE SENSIBLE WX
NOTED BESIDES THE WIND SHIFT WITH SLIGHT BUMP IN SPEEDS AND
INCREASED DEWPOINTS. EXPECT PARTLY CLOUDY SKIES INCREASING DURING
THE DAY AS ISENTROPIC LIFT INCREASES FROM THE W AND NW. A SLIGHT
CHANCE AROUND 20 PRCT IS INDICATED OVER OUR FAR NW ZONES AS LIFT
INCREASES IN ASSOCD WITH MID LEVEL SHORTWAVE ENERGY. MAX TEMPS AGAIN
NEAR CLIMATOLOGY IN THE 60S MOST LOCATIONS.
FRIDAY NIGHT THROUGH SATURDAY NIGHT...THE EXTENDED DRY WEATHER
PERIOD COMES TO A CLOSE AS SFC LOW CONTINUES TO DEVELOP OVER THE
NORTHERN GULF OF MEX AND TRAVEL EASTWARD TOWARDS THE FL PENINSULA.
LOW LEVEL MOISTURE WILL PUSH INTO THE AREA AHEAD OF THIS SYSTEM
INCREASING PRECIP CHANCES FRIDAY NIGHT INTO SATURDAY WITH THE
HIGHEST CHANCES...AROUND 40 TO 50 PERCENT...DURING THE AFTERNOON
SATURDAY ACROSS SE GA CLOSEST TO THE MID LEVEL IMPULSE PASSING TO
THE NORTH OVER CENTRAL GA. LOWER PRECIP CHANCES EXPECTED OVER NE
FL WITH LESS UPPER LEVEL SUPPORT. MINIMUM TEMPS WILL MODERATE
FRIDAY AND SATURDAY NIGHTS INTO THE UPPER 40S AND 50S WITH
INCREASED CLOUD COVER. MAX TEMPS SATURDAY WILL REMAIN NEAR NORMAL
ACROSS SE GA IN THE LOW/MID 60S WITH NE FL WARMING INTO THE UPPER
60S TO LOW 70S WITH A FEW MORE BREAKS IN THE CLOUDS.
.LONG TERM...
SUNDAY THROUGH WEDNESDAY....LONG TERM MODELS IN DECENT AGREEMENT
ON THE TIMING OF FOLLOWING SHORTWAVE AS IT RUNS UP OVER A FRONTAL
BOUNDARY WHICH HAS BECOME MOSTLY STATIONARY OVER THE AREA SUNDAY INTO
MONDAY. RAIN CHANCES WILL INCREASE FROM SUNDAY NIGHT INTO MONDAY
WITH LIKELY CHANCES ON MONDAY AS DEEP SOUTHWESTERLY FLOW LIFTS
RELATIVELY WARM AIRMASS OVER COOLER AIR. COVERAGE OF PRECIP SHOULD
DECREASE MONDAY NIGHT AS SFC LOW MOVES OFF TO THE NORTHEAST UP THE
ATLANTIC COAST BUT WILL INCREASE ONCE AGAIN ON TUESDAY AS UPPER
TROUGH DEEPENS OVER THE GREAT LAKES REGION WITH SFC LOW AND
ASSOCIATED COLD FRONT PULLING MOISTURE UP OVER THE AREA AS THE
BOUNDARY APPROACHES THE REGION. THUNDERSTORMS WILL BE POSSIBLE TUESDAY
INTO EARLY WEDNESDAY WITH UPPER TROUGH CONTINUING TO DEEPEN AND
BECOME NEGATIVELY TILTED AND SFC COLD FRONT PASSES THROUGH. CURRENT WPC
QPF FORECASTS SHOWING RAINFALL TOTALS SUNDAY THROUGH WEDNESDAY UP
TO 3 INCHES WITH HIGH LEVELS OF AVAILABLE MOISTURE AND PERSISTENT FORCING
MECHANISMS. CONDITIONS WILL BEGIN TO IMPROVE ON WEDNESDAY AS COLD
FRONT PUSHES THROUGH AND DRIER AIRMASS FILTERS IN BEHIND. MILD
TEMPERATURES EXPECTED EACH AFTERNOON SUNDAY THROUGH TUESDAY IN THE
60S AND LOW 70S BEFORE COLD AIR ADVECTION INITIATES ON WEDNESDAY
AND TEMPS BEGIN TO DECREASE. MIN TEMPS WILL FOLLOW SUIT IN THE
UPPER 40S AND 50S ACROSS MUCH OF THE AREA EACH NIGHT UNTIL
WEDNESDAY NIGHT WHEN COLDER TEMPS ARE EXPECTED.
&&
.AVIATION...VFR BUT BRIEF VSBY REDUCTIONS POSSIBLE AT VQQ.
OCNL CIGS AOA 20 KFT THROUGH 06Z FRI. LIGHT NW TO W WINDS...THOUGH A
WEAK SEA BREEZE WILL BE POSSIBLE AT SSI AFTER 20Z.
&&
.MARINE...BENIGN CONDITIONS CONTINUE THROUGH FRIDAY WITH FAIRLY
LIGHT NLY WINDS AND LOW SEA HEIGHTS. NELY FLOW LIGHT ON FRIDAY AND
SHIFTS TO MORE SLY ON SAT. A WEAK AREA OF LOW PRESSURE AND
ASSOCIATED COLD FRONT WILL MOVE EASTWARD AND STALL ACROSS THE WATERS
SUNDAY AND MONDAY MAKING FOR UNSETTLED WEATHER WITH A GOOD CHANCE OF
RAIN. ANOTHER STRONGER COLD FRONT WILL APPROACH FROM THE W BY
TUESDAY. STILL CAN`T TOTALLY DISCOUNT A CHANCE OF SEA FOG EARLY SAT
MORNING AND/OR SAT EVENING AS DEWPOINTS INCREASE AS FLOW TURNS TO NE
AND SE BUT POTENTIAL SEEMS TOO LOW TO INCLUDE ATTM.
RIP CURRENTS: LOW RISK EXPECTED THROUGH FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 63 38 64 49 / 0 0 10 30
SSI 61 44 62 52 / 0 0 10 20
JAX 64 41 66 51 / 0 0 10 10
SGJ 64 46 65 55 / 0 0 10 10
GNV 66 40 68 51 / 0 0 10 10
OCF 67 40 70 52 / 0 0 10 10
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
GUILLET/SHASHY/
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1205 AM CST THU DEC 18 2014
.SHORT TERM...
230 PM CST
THROUGH FRIDAY...
RELATIVELY BENIGN WEATHER ON TAP IN THE NEAR TERM UNDER THE
INFLUENCE OF HIGH PRESSURE WHICH WILL REMAIN OVER THE REGION INTO
THE WEEKEND. SURFACE RIDGE EXTENDS FROM MANITOBA INTO THE LOWER
MISSISSIPPI VALLEY THIS AFTERNOON WHILE ALOFT A SHEARED VORT MAX IS
DIGGING SOUTHEAST ACROSS FAR NORTHERN ILLINOIS. SOUNDINGS INDICATE
STEEP LOW LEVEL LAPSE RATES UP TO AROUND 900MB THIS AFTERNOON AND
RADAR IMAGERY DOES SHOW SIGNS OF SOME CONVECTIVE ROLLS WITH VERY
WEAK WIND PARALLEL RETURNS. WITH THESE INGREDIENTS IN PLACE...A FEW
FLURRIES HAVE BEEN NOTED ACROSS THE AREA...BUT NOTHING OF
CONSEQUENCE. ANY FLURRIES SHOULD TAPER BY MID-LATE AFTERNOON AS
INVERSION HEIGHTS BEGIN TO COME DOWN IN RESPONSE TO MODERATE TO
STRONG MID LEVEL HEIGHT RISES BEHIND DEPARTING SHORTWAVE. STRATUS
DECK REMAINS IN PLACE TODAY BUT HAS BEGUN TO THIN AND ERODE NEAR
THE WESTERN COUNTIES. ANY PEAKS OF SUNSHINE TODAY THOUGH ARE
EXPECTED TO BE BRIEF AS MID LEVEL CLOUD COVER INCREASES FROM THE
NORTH AS A WEAK TROUGH EMBEDDED ON THE EASTERN PERIPHERY OF THE
HIGH SAGS SOUTH ACROSS LAKE MICHIGAN...AND FROM THE SOUTHWEST AS
ANOTHER SHORTWAVE TROUGH CURRENTLY LIFTING ACROSS THE PANHANDLES
OF TX/OK PUSHES ACROSS CENTRAL ILLINOIS MIDDAY THURSDAY. PRECIP
WITH THIS SYSTEM IS EXPECTED TO STAY SOUTH OF THE CWA...TAPERING
AS IT OVERRIDES THE SURFACE RIDGE. CLOUD COVER MAY CONTINUE TO
REMAIN LOCKED IN UNDER THE INVERSION FRIDAY...BUT OTHERWISE EXPECT
VERY LIGHT WINDS AND DRY CONDITIONS ON SQUARELY UNDER THE SURFACE
HIGH.
DEUBELBEISS
&&
.LONG TERM...
230 PM CST
FRIDAY NIGHT THROUGH THURSDAY...
HIGH PRESSURE WILL CONTINUE TO SLOWLY SHIFT EAST ACROSS THE REGION
OVER THE WEEKEND WITH RETURN FLOW BRINGING WARMER TEMPERATURES
ESPECIALLY BY SUNDAY. MEANWHILE...THE PATTERN IS PROGGED TO BEGIN
AMPLIFYING BY LATE IN THE WEEKEND AS LONGWAVE TROUGH DEEPENS ACROSS
THE MID SECTION OF THE COUNTRY DOWNSTREAM OF A BUILDING RIDGE ALONG
THE WEST COAST. THE JET STREAM WILL DIVE TOWARDS THE GULF STATES BY
TUESDAY WITH SURFACE LOW DEEPENING IN RESPONSE EARLY NEXT WEEK.
THERE REMAIN SIGNIFICANT DIFFERENCES AS WELL AS RUN-TO-RUN
VARIABILITY IN THE TIMING AND TRACK OF THE LOW AS IT LIFTS ACROSS
THE MIDWEST MIDWEEK...WITH COMPLICATIONS AS THE MODELS DEAL WITH
PHASING THE SOUTHERN LOW WITH A CLIPPER LIKE SYSTEM. WILL
CERTAINLY HAVE TO KEEP AN EYE ON THE POTENTIAL FOR ACCUMULATING
SNOW TUESDAY INTO WEDNESDAY OVER THE NEXT SEVERAL DAYS AS MODELS
HOPEFULLY BEGIN TO HONE IN ON A SOLUTION. A RETURN TO BELOW NORMAL
CONDITIONS SEEMS LIKELY FOR THE LATTER HALF OF THE WEEK.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS THIS MORNING. CMS
//DISCUSSION...UPDATED 06Z...
MVFR CIGS CONTINUE TO SLOWLY ERODE FROM THE NORTH WHILE REMAINING
STEADY TO THE SOUTHWEST...RPJ/C09/IKK. CONFIDENCE REGARDING TRENDS
IS LOW BUT IF THEY CONTINUE...WILL LIKELY SEE SOME SCATTERING OF
LOW CLOUDS FROM THE NORTH OVERNIGHT...WITH CLEARING AT GYY/MDW
LIKELY TO BE LATER THIS MORNING. NORTHWEST WINDS 4-8KTS WILL
LIKELY BECOME LIGHT AND VRB WHERE CLOUDS CLEAR...WITH LIGHT
NORTHWEST WINDS THRU THE DAY AND BECOMING LIGHT AND VRB TONIGHT.
CMS
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM FOR CIGS THRU THE PERIOD. CMS
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY AND SATURDAY...DRY WITH VFR LIKELY...THOUGH MVFR POSSIBLE.
LIGHT AND VARIABLE WINDS.
SUNDAY...DRY. MVFR POSSIBLE. SOUTH WINDS.
MONDAY...CHANCE OF RAIN. MVFR LIKELY. GUSTY SOUTH WINDS...POSSIBLY
TURNING SOUTHEAST.
TUESDAY...CHANCE OF RAIN MIXED WITH SNOW. IFR POSSIBLE. SOUTHWEST
WINDS.
KMD
&&
.MARINE...
210 PM CST
THE LOW PRESSURE THAT PASSED THROUGH THE GREAT LAKES REGION OVER THE
PAST COUPLE DAYS IS IN THE PROCESS OF MERGING WITH ANOTHER LOW OVER
THE NEW ENGLAND COAST. THIS LOW WILL GRADUALLY DEEPEN AND SLOWLY
MOVE NORTH ALONG THE NEW ENGLAND COAST AS HIGH PRESSURE SPREADS FROM
THE NORTHERN PLAINS AND ACROSS THE WESTERN GREAT LAKES BY THURSDAY
MORNING. WINDS ARE SLOWLY SUBSIDING OVER THE LAKE...BUT A SECONDARY
TROUGH AND SURGE OF COOLER AIR MOVING DOWN THE LAKE THIS AFTERNOON
AND EVENING WILL KEEP RELATIVELY BRISK NLY-NLWY WINDS OVER THE LAKE
THROUGH THE NIGHT TONIGHT. WINDS SHOULD WEAKEN TO THE 10-15KT RANGE
THURSDAY NIGHT AND FRIDAY AS THE HIGH GRADUALLY SPREADS EAST...WHILE
MAINTAINING A NLY DIRECTION. THE HIGH WILL SPREAD ACROSS LAKE
MICHIGAN THURSDAY NIGHT AND FRIDAY...LEADING TO MORE LGT/VRBL WINDS
OVER THE LAKE. HIGH PRESSURE WILL VERY SLOWLY SPREAD EWD...BUT
STILL CONTROLLING FLOW OVER THE LAKE...KEEPING WINDS GENERALLY LIGHT
AND VARIABLE INTO THE WEEKEND. BY SUNDAY...THE HIGH WILL FINALLY
PUSH EAST OF LAKE MICHIGAN AS A TROUGH OF LOW PRESSURE DEVELOPS OVER
THE NORTHERN PLAINS. THIS WILL SET UP INCREASING SLY FLOW OVER THE
LAKE BY SUNDAY. A DEVELOPING LOW IS EXPECTED TO TRACK ACROSS THE
NRN PLAINS SUNDAY NIGHT AND MONDAY...REACHING THE MIDDLE MISSISSIPPI
VALLEY BY TUESDAY. THIS WILL KEEP GENERALLY SOUTHERLY WINDS OVER
THE LAKE THROUGH EARLY NEXT WEEK.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL
10 AM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1134 PM CST Wed Dec 17 2014
.UPDATE...
ISSUED AT 909 PM CST WED DEC 17 2014
Have already made one adjustment to cloud cover since it is not
clearing as fast as originally expected. Will be making another
adjustment for the same thing with high clouds advecting in from
the southwest. Pcpn is moving across MO and still expected to
arrive in western IL in the morning. Forecast still has good
handle on this. Most of forecast looks fine, but will be updating
to reflect current cloud trends. Update coming shortly.
&&
.SHORT TERM...(Tonight)
ISSUED AT 245 PM CST WED DEC 17 2014
19z/1pm satellite imagery continues to show overcast conditions
across much of central Illinois: however, the clouds are beginning
to erode northwest of the Illinois River. While HRRR guidance has
not been particularly useful in the short-term, satellite trends
suggest skies will partially clear across all but the far E/NE KILX
CWA by early evening. After a period of mostly clear skies early
tonight, clouds will once again begin increasing in advance of the
next storm system, which is currently evident on water vapor imagery
over west Texas. Quite a bit of precip and even some thunder is
occurring ahead of this wave over Oklahoma/Texas: however, it is
expected to weaken as it lifts northeastward into the region on
Thursday. It will also be coming into a dry airmass beneath a
prevailing surface ridge axis. Forecast soundings show gradual
moistening from the top-down later tonight, but the lowest levels
below 850mb will remain quite dry through 12z. As a result, have
maintained a dry forecast through the overnight hours. Due to the
initially clear skies and low dewpoints, have gone a couple of
degrees below MAV guidance for lows tonight, with readings dropping
into the teens and lower 20s.
&&
.LONG TERM...(Thursday through Wednesday)
ISSUED AT 245 PM CST WED DEC 17 2014
Upper flow will be zonal for next few days, with weak waves moving
east through flow. Moisture channel data and upper air shows initial
wave to affect region over NM this morning. This system to
continue tracking to the northeast, pushing some overrunning pcpn
into MO and southern 1/2 of IL for late tonight into Thursday. Weak
vort lobe and isentropic lift to be enough to move the light snow
into southern 1/2 of CWA in the morning, but wave moving fast enough
to only affect the morning. Mainly less than half inch.
Next wave to move into region for Friday night and Saturday morning
and the area of lift with this one is farther south, mainly over
southeast cwa. Again, some light snow possible.
Upper flow starts to change on late in weekend and by Monday, flow
is northwest. Digging upper trough over Great Lakes with upper low
closing off by Monday night. This will bring some initial pcpn into
the region ahead of cold front that moves through Tuesday.
Temperatures however, are only cold enough for possible mixture
until post frontal on Tuesday night and Wednesday. Therefore no snow
accumulation. However by Tues night to Wed, only minor vort lobes
rotating around the closed upper low in the cold air, so chance of
light snow accumulations only.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1134 PM CST WED DEC 17 2014
Clouds are still slowly exiting the area to the east. BMI, DEC,
and CMI still have broken to overcast clouds at MVFR levels. These
will eventually head east but broken cirrus has overspread all TAF
sites. As the next system advances closer to the area, clouds will
lower into the mid range to around 8kft at all sites sometime
during the morning, with SPI lower first. Models continue to show
very light snow getting to SPI only. So this is the only site
where I have cigs dropping to MVFR and having light snow/flurries
in the TAFs. All other sites will see slightly lower clouds to
around 5kft. Could be some MVFR cigs that slide over the other
sites, so will have TEMPO groups of 3-4 hrs for the others to
account for possible cigs around 3kft. During the late afternoon all
sites should see lower clouds scatter/dissipate with cirrus left
the rest of the evening. Winds will remain light and variable due
to the high pressure ridge sitting right over the area.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Auten
SHORT TERM...Barnes
LONG TERM...Goetsch
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1141 PM CST WED DEC 17 2014
.SHORT TERM /TONIGHT/...
ISSUED AT 245 PM CST WED DEC 17 2014
A QUIET AFTERNOON IS IN STORE FOR THE CWA WITH SURFACE HIGH PRESSURE
ANCHORED ALONG THE MISSOURI RIVER VALLEY. A SHARP 300 MB SHORTWAVE
TROUGH CURRENTLY EJECTING FROM THE FOUR CORNERS REGION WILL ENTER
SOUTHWEST IOWA BY 12Z THURSDAY. NAM/GFS ARE TOO SLOW WITH RETURNING
MID-LEVEL MOISTURE (MANIFESTING ITSELF AS AN ALTOSTRATUS DECK) NOW
WELL INTO SW IOWA AS WELL AS WITH PRECIP COVERAGE WITH THIS SYSTEM
IN OKLAHOMA. THE HRRR BEST REFLECTS REALITY IN TERMS OF PRECIP
COVERAGE BUT IS ABOUT 3 HOURS BEHIND THE CURVE WITH CLOUD PLACEMENT.
HAVE SUBSEQUENTLY MANUALLY INCREASED CLOUD COVER OVER THE SW HALF OF
THE CWA AND USED THE HRRR FOR TIMING THE ONSET OF SNOW IN THE
SOUTHWESTERN CWA. LOW TEMPERATURES TONIGHT...ESPECIALLY OVER THE
NORTH...WILL BE DEPENDENT ON HOW QUICKLY CLOUDS CAN ADVECT OVERHEAD.
THESE WILL NEED TO BE MONITORED THIS EVENING AND ADJUSTED UPWARD
SHOULD THE CLOUDS ADVANCE FASTER THAN CURRENTLY FORECAST.
THE FASTER MOISTURE RETURN THROWS JUST ANOTHER WRENCH IN TIMING AND
AMOUNTS OF SNOWFALL IN SOUTHERN IOWA LATE TONIGHT. 12/18Z MODEL BUFR
SOUNDINGS DEPICT A STOUT 925-850MB DRY WEDGE ATTENDANT WITH THE
SURFACE RIDGE...BUT THIS MIDLEVEL MOISTURE MAY SATURATE THE COLUMN
FASTER THAN PROGGED AND LEAD TO HIGHER SNOWFALL TOTALS. OVERALL MADE
LITTLE CHANGES TO THE FORECAST IN THIS RESPECT...BUT DID TIGHTEN THE
POP GRADIENT AS IT ADVANCES NORTHEAST FROM 09 TO 12Z THINKING THAT
THE LOW LEVEL DRY AIR WILL RESULT IN A SHARP CUTOFF IN ACCUMULATING
SNOW.
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
ISSUED AT 245 PM CST WED DEC 17 2014
A FEW CHALLENGES OVER THE EXTENDED PERIOD...WITH A NUMBER OF WEAK
SYSTEMS TO AFFECT PORTIONS OF THE AREA THROUGH THE PERIOD. SPLIT
FLOW CONTINUES TO BE THE MAIN DRIVING FORCE BEHIND THE RATHER
QUIESCENT WEATHER FOR MID DECEMBER. RATHER HIGH AMPLITUDE RIDGE OF
HIGH PRESSURE STILL ANCHORED FROM THE NORTHERN PLAINS TO THE GULF
COAST NEXT FEW DAYS. FIRST WAVE CURRENTLY OVER THE SOUTHERN
PLAINS TODAY AND SHOULD MOVE NORTHEAST THROUGH THU MORNING. AHEAD
OF THE WEAK SYSTEM WARM AIR ADVECTION AND LIMITED MOISTURE WILL BE
FORCED UPWARD IN AN AREA OF ISENTROPIC LIFT OVER SOUTHERN IOWA
THURSDAY. THE LIFT AND MOISTURE WILL BE ATTEMPTING TO OVERCOME THE
DRY AIRMASS CURRENTLY IN PLACE...LIMITING OVERALL AMOUNTS. THIS
WILL RESULT IN SOME RATHER LIGHT SNOW DURING THE MORNING HOURS
WITH MINOR ACCUMULATIONS GENERALLY LESS THAN AN INCH. DURING THE
EARLY AFTERNOON HOURS...BUFR SOUNDINGS SHOW THAT WE LOSE ICE
INTRODUCTION ACROSS THE SOUTHWEST AND SOUTH. HAVE INTRODUCED SOME
PATCHY FREEZING DRIZZLE ALONG WITH VERY LIGHT SNOW DURING THE
AFTERNOON HOURS...THOUGH EXPECTATIONS ARE THAT ANY PRECIPITATION
BY THAT TIME WILL BE VERY LIGHT AND LITTLE IF ANY ICE ACCUMULATION
IS EXPECTED. NEXT SYSTEM ARRIVES BY SUNDAY AND MONDAY AND EXTENDS
INTO TUESDAY. LOWER CONFIDENCE MOVING FORWARD WITH A CONSENSUS
SOLUTION AS THE GFS IS QUITE MILD WHILE THE EURO IS NOW SUGGESTING
A SOLUTION WITH MORE SIGNIFICANT DYNAMIC COOLING AS THE PRECIP
ARRIVES INTO MONDAY. THE EURO SUGGESTS MORE SNOW THAN RAIN/SNOW
MIX. GIVEN THE EVENT IS STILL 5 DAYS AWAY...WILL HOLD ONTO CURRENT
MIX TRENDS FOR NOW...AND MONITOR DURING SUBSEQUENT MODEL PACKAGES.
THE ONE TREND THAT IS BEGINNING TO EMERGE IS COLDER AIR AS NEXT
WEEK PROGRESSES. AS A STRONG PACNW STREAM WAVE ADVANCES EAST INTO
THE WESTERN STATES...MIDWEST RIDGE FINALLY BEGINS TO BREAK DOWN
AND BECOME DISPLACED BY A LONG WAVE TROUGH. THIS SHOULD SPELL A
TRANSITION TO A MORE ACTIVE AND COLDER PATTERN TOWARD THE END OF
THE EXTENDED. AS THE WAVE TUESDAY DEEPENS...A RATHER STRONG SFC
WAVE WILL EJECT NORTH NORTHEAST OUT OF EASTERN TEXAS TO EASTERN
MICHIGAN WEDNESDAY. GIVEN THE CURRENT GFS/EURO PACKAGES...THE MAIN
H850 MOISTURE PLUME...BETTER FORCING...AND HIGHER PRECIPITATION
AMOUNTS WILL PROBABLY END UP EAST OF THE REGION. WILL MONITOR FOR
GENERAL WESTWARD DRIFT NEXT SEVERAL PACKAGES...THIS SOMETIMES
OCCURS WITH WINTER STORM EVOLUTION IN MODEL PACKAGES...FIRST
PROJECTING THE EVENT TOO FAR EAST THEN PULLING IT BACK AS THE
EVENT NEARS.
&&
.AVIATION...18/06Z
ISSUED AT 1140 PM CST WED DEC 17 2014
SYSTEM ACROSS PLAINS WILL CONTINUE TO LIFT NORTHEAST THROUGH
THURSDAY. CLOUDS WILL MOVE INTO IOWA WITH PRIMARILY MID AND HIGH
CLOUDINESS OVERNIGHT AND VFR CONDITIONS. AS DEEPER SATURATION
APPROACHES FROM THE SOUTH TOWARD DAYBREAK...MVFR TO IFR CONDITIONS
NEAR THE MISSOURI BORDER ARE EXPECTED ALTHOUGH DRIER LOW LEVEL AIR
WILL KEEP LOCATIONS FARTHER NORTH VFR. THERE WILL BE SOME LOW
LEVEL CLOUDS NEAR KMCW OVERNIGHT NEAR RIDGE AXIS AND THIS MAY
LINGER INTO THURSDAY MORNING AS FLOW REMAINS QUITE LIGHT. WITH
PASSAGE OF SYSTEM ON THURSDAY...THREAT OF PRECIPITATION IN THE
SOUTH WILL END AFTER MIDDAY. HOWEVER...LOW TO MID LEVEL MOISTURE
WILL REMAIN WITH WIDESPREAD STATUS EXPECTED TO PERSIST THROUGH THE
END OF THE FORECAST.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SKOW
LONG TERM...REV
AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
245 AM MST THU DEC 18 2014
.SHORT TERM...(THIS MORNING THROUGH SATURDAY NIGHT)
ISSUED AT 244 AM MST THU DEC 18 2014
EARLY MORNING WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW SHORTWAVE
TROUGH OVER NORTHCENTRAL KANSAS WITH AREA OF SUBSIDENCE ALONG
SHORTWAVE RIDGE AXIS BUILDING INTO THE NEBRASKA PANHANDLE. AT THE
SURFACE A STATIONARY FRONT REMAINS IN PLACE OVER EASTERN COLORADO
WITH SOUTH TO SOUTHEAST FLOW IN PLACE ACROSS OUR CWA.
REGARDING WINTER WEATHER ADVISORY EARLY THIS MORNING....
RADAR AND SURROUNDING OBS SHOW A BAND OF LIGHT SNOW THAT FORMED ON
BACK SIDE OF H7 LOW MOVING EAST OVER OUR EASTERN CWA. THIS SNOW HAS
HELPED MIX OUT THE LOW LEVELS OF THE ATMOSPHERE WITH SHIFT IN LOW
LEVEL FLOW TO THE NORTHWEST AIDING IMPROVEMENT IN CONDITIONS
ACROSS THE WESTERN FORECAST AREA. BASED ON SHORT RANGE MODELS...I
AM STILL CONCERNED THAT LIGHT WINDS AND SHALLOW LOW LEVEL MOISTURE
COULD LEAD TO FREEZING FOG REDEVELOPMENT BEHIND THIS SNOW BAND.
FREEZING FOG/DRIZZLE WILL REMAIN POSSIBLE AHEAD OF IT WITH BETTER
MOISTURE ADVECTION/POOLING. OVERALL TREND THROUGH THE MORNING
SHOULD BE IMPROVEMENT IN CONDITIONS AROUND 12-15Z...WITH ANY FOG
CLEARING BY MIDDAY. AFTER 12Z I AM SKEPTICAL THAT FLOW WOULD ALLOW
FOR ENOUGH ADDITIONAL MOISTURE ADVECTION TO SUPPORT CONTINUED
FREEZING DRIZZLE...THOUGH FOG COULD BE POSSIBLE THROUGH MOST OF
THE MORNING ESPECIALLY IN THE EAST WHERE SOUTHERLY FLOW MAY LINGER
A LITTLE LONGER. WITH THIS IN MIND I PLAN ON HOLDING ONTO CURRENT
WINTER WEATHER ADVISORY THROUGH EXPIRATION IN CASE I NEED TO
EXTEND IT IN TIME FOR EASTERN LOCATIONS THROUGH 15Z.
REST OF TODAY...SHORTWAVE RIDGING WILL CONTINUE TO BUILD EAST
TODAY AND AIR MASS WILL BEING MODERATING AND DRYING AS SURFACE
TROUGH SHIFTS EAST. THERE MAYBE DECENT CLEARING WHICH COULD
SUPPORT TEMPS IN THE LOWER 40S (FOR LOCATIONS WITHOUT SNOW PACK).
IT IS TOUGH TO SAY HOW MUCH CLEARING AS MODELS HOLD ONTO STRATUS
OVER PARTS OF THE AREA INTO THE AFTERNOON. NOT A LOT OF
CONFIDENCE IN TEMPS...SO MADE MINOR ADJUSTMENT TO TODAYS HIGHS.
TONIGHT-SATURDAY NIGHT...A SHORTWAVE TROUGH WILL PASS THROUGH THE
SOUTHERN PLAINS THROUGH FRIDAY MORNING...WITH MINIMAL IMPACT ON
SENSIBLE WEATHER OVER OUR CWA. NAM AND SREF BL RH CONTINUE TO RUN
HIGH...LIKELY AS A RESULT OF SNOW PACK...AND SUPPORT FOG/STRATUS
DURING THE OVERNIGHT PERIODS. I ADDED PATCHY FOG TO TONIGHT AS
WINDS WILL BE LIGHT AND THERE COULD BE SOME LINGERING BL MOISTURE
POOLING ALONG AND EAST OF SURFACE TROUGH...THOUGH CONFIDENCE IS
PRETTY LOW AS TROUGH MAY BE EAST OF OUR CWA. THOUGH TEMPS WILL BE
SUBFREEZING...CONFIDENCE IS TOO LOW THAT ANY FOG WOULD BE DENSE
ENOUGH TO WORRY ABOUT ICE ACCUMULATION (FREEZING FOG). I AM
LEAVING FOG OUT OF FRIDAY NIGHT AND SATURDAY NIGHT TO SEE HOW
THINGS EVOLVE TONIGHT FIRST. SHORTWAVE RIDGE SHOULD BUILD BACK
OVER THE PLAINS FRIDAY THROUGH SATURDAY...WITH CONTINUED
MODERATION OF THE AIR MASS ALOFT. COMPLICATION TO TEMP FORECAST
WILL CONTINUE TO BE IMPACT OF DEEPER SNOW PACK IN OUR NORTHWEST
CWA.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 244 AM MST THU DEC 18 2014
THE LONG TERM PERIOD WILL START OUT WITH SLIGHTLY ABOVE AVERAGE
TEMPERATURES ON SUNDAY WITH WARM SOUTHERLY WINDS KEEPING
TEMPERATURES IN THE MID TO UPPER 40S. THE NEXT WEATHER MAKING
SYSTEM WILL APPROACH THE HIGH PLAINS REGION AS AN UPPER LEVEL TROUGH
AND SURFACE LOW PRESSURE SYSTEM MOVE ACROSS THE NORTHERN PLAINS.
THIS SYSTEM WILL BRING IN COLDER AIR TO THE PLAINS WITH CHANCES FOR
PRECIPITATION STARTING EARLY MONDAY MORNING...MOSTLY FOR EASTERN
COLORADO LOCATIONS.
PRECIPITATION MONDAY WILL BEGIN AS SNOW IN THE MORNING WITH COOLER
TEMPERATURES AT THE LOWER LEVELS...BUT WILL BECOME RAIN IN THE
AFTERNOON WITH HIGH TEMPERATURES REACHING THE MID 40S TO LOWER 50S.
AFTER SUNSET...PRECIPITATION WILL TRANSITION BACK TO SNOW THROUGH
THE OVERNIGHT HOURS. UNDER AN INCH OF SNOW IS POSSIBLE WITH THIS
SYSTEM.
THE UPPER LEVEL LOW IS DEPICTED IN GUIDANCE AS STALLING OVER THE
UPPER MIDWEST STATES...BUT THE TRI STATE AREA WILL BE UNDER THE
INFLUENCE OF STRONG NORTHWEST FLOW TUESDAY AS AN UPPER LEVEL RIDGE
BUILDS IN THE WEST. THE HIGHER AMPLITUDE RIDGE WILL BREAK DOWN AND
MOVE WESTWARD TO BRING A SHORTWAVE RIDGE OF HIGH PRESSURE OVER THE
CENTRAL PLAINS TO BRING DRY CONDITIONS AND NEAR AVERAGE TEMPERATURES
FOR TUESDAY AND WEDNESDAY. HIGH TEMPERATURES WILL RANGE FROM THE
UPPER 30S TO MID 40S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1033 PM MST WED DEC 17 2014
FOR BOTH TAF SITES FROM 06Z-15Z THURSDAY...MAINLY LIFR/VLIFR
CONDITIONS WITH BRIEF IFR/MVFR MIX THRU 09Z. CEILINGS MAINLY 1/4SM
TO 1/2SM IN A SNOW/FREEZING FOG MIX...WITH PERIODS 1-3SM THRU 09Z.
FROM 15Z ONWARD...IFR CONDITIONS TREND TO VFR BY 00Z FRIDAY.
CEILINGS WILL RANGE FROM BKN-OVC006-010 UP TO BKN100 BY 00Z
FRIDAY. 3-6SM IN FOG DURING THIS TIME...ESPECIALLY BEFORE 00Z
FRIDAY. WINDS MAINLY VARIABLE THRU 15Z...THEN WSW 5-10KTS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY UNTIL 5 AM MST /6 AM CST/ EARLY THIS
MORNING FOR KSZ001>004-013>016-027>029-041-042.
CO...WINTER WEATHER ADVISORY UNTIL 5 AM MST EARLY THIS MORNING FOR
COZ090>092.
NE...WINTER WEATHER ADVISORY UNTIL 5 AM MST /6 AM CST/ EARLY THIS
MORNING FOR NEZ079>081.
&&
$$
SHORT TERM...DR
LONG TERM...MK
AVIATION...JN
AREA FORECAST DISCUSSION
NWS JACKSON KY
359 AM EST THU DEC 18 2014
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 358 AM EST THU DEC 18 2014
SURFACE HIGH PRESSURE CONTINUES TO BE IN CHARGE FOR THE OHIO RIVER
VALLEY AND MANY POINTS TO OUR NORTH AND SOUTH. STRONG SUBSIDENCE
TRAPPING LOW LEVEL MOISTURE ACROSS THE NE PORTION OF THE CWA HAS LED
TO CONTINUED MVFR CLOUDS...WHICH ACCORDING TO THE LATEST FORECAST
SOUNDINGS...SHOULDN/T BE BUDGING UNTIL SOMETIME EARLY THIS
AFTERNOON. MEANWHILE...ALOFT...A SHORTWAVE IS CONTINUING TO DAMPEN
AS IT TRACKS EASTWARD...AND SHOULD BE POISED TO REACH THE
MISSISSIPPI RIVER VALLEY BETWEEN 12 AND 18Z TODAY. SO FAR...THIS
SYSTEM HAS BROUGHT LIGHT PRECIP ACROSS FAR SW KY...AS IT CONTINUES
TO SHIFT EASTWARD TOWARDS OUR SW CWA DURING THE EARLY MORNING HOURS.
THE AMOUNT OF LOW LEVEL DRY AIR IS STILL A CONCERN IN THIS AREA OF
THE CWA...AND WHETHER OR NOT THE PRECIP CAN OVERCOME IT. EXPECTING
BEST CHANCES FOR WEATHER ACROSS WAYNE AND MCCREARY COUNTIES GIVEN
THE LATEST HI RES MODEL DATA...INCLUDING THE HRRR AND ECMWF.
FORECAST SOUNDINGS ARE SHOWING BELOW FREEZING SURFACE TEMPS AT THESE
LOCATIONS...BUT WITH THE POTENTIAL FOR A SLIGHT WARM NOSE TEETERING
ALONG THE FREEZING LINE SEVERAL THOUSAND FEET ABOVE GROUND THROUGH
18Z. AS SUCH...WENT AHEAD AND MENTIONED SOME ICE PELLETS ALONG WITH
A CHANCE OF SNOW IN THESE TWO COUNTIES...WITH A SLIGHT CHANCE OF
LIGHT SNOW EVENTUALLY MIXING WITH RAIN AFTERWARDS ELSEWHERE IN THE
SW CWA.
THE SHORTWAVE WILL EVENTUALLY FLATTEN AND SHIFT EAST OF KY BY 06Z
FRIDAY ELIMINATING ANY FURTHER PRECIP CONCERNS FOR THE SHORT TERM.
THE ONE CAVEAT WILL BE THE EXISTENCE OF THE MID LEVEL CLOUDS WITH
MUCH OF THE TEMPERATURE PROFILE /INCLUDING SURFACE TEMPS/ DROPPING
BELOW FREEZING BY THIS EVENING AND THROUGHOUT THE OVERNIGHT. A FEW
FLURRIES MAY GET SQUEEZED OUT ACROSS THE CWA DURING THE EVENING. IN
FACT...MAY NOT HAVE EXTENDED THE FLURRY POTENTIAL FAR ENOUGH ACROSS
THE CWA. BUT THE CONFIDENCE IS STILL QUITE LOW ON THIS SUBJECT.
CONTINUED TO GO ABOVE GUIDANCE FOR CLOUD COVER OVER THE NEXT 36
HOURS AS MID/LOW LEVEL CLOUDS LOOK TO STICK AROUND THROUGH
FRIDAY...BEFORE ANOTHER ROUND OF HIGH CLOUDS WORKS INTO THE CWA.
THIS MAY INHIBIT SOME OF THE BEST RIDGE VALLEY SPLIT POTENTIAL
TONIGHT. OVERALL...TEMPERATURES SHOULD/T DEVIATE MUCH FROM WHAT WAS
SEEN IN THE PREVIOUS 24 HOURS. HIGHS TODAY WILL GENERALLY BE IN THE
UPPER 30S AND LOW 40S...WITH OVERNIGHT LOWS TONIGHT DROPPING DOWN
INTO THE UPPER 20S. WINDS AT THE SURFACE WILL REMAIN QUITE LIGHT AND
VARIABLE THROUGH THE SHORT TERM...WHILE ABOVE THE CONTINUED MID
LEVEL SUBSIDENCE INVERSION...THEY WILL INCREASE RAPIDLY THANKS TO A
WEST TO EAST ORIENTED JET STREAK WHICH IS CURRENTLY PUSHING ALONG
AND SOUTH OF KY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014
A FAIRLY ACTIVE PATTERN IN STORE FOR THE EXTENDED PORTION OF THE
FORECAST. THE MODELS AREA IN PRETTY GOOD AGREEMENT WITH THE LARGE
SCALE UPPER LEVEL FLOW PATTERN THROUGH MID WEEK. THREE SYSTEMS ARE
FORECAST TO AFFECT EASTERN KENTUCKY...THE FIRST BEING A WEAK AREA OF
LOW PRESSURE THAT IS FORECAST TO FORM OVER THE SOUTHERN PLAINS AND
THEN PROGRESS EASTWARD ACROSS THE GULF COAST FRIDAY NIGHT THROUGH
SATURDAY NIGHT. THE SECOND AND THIRD WEATHER SYSTEMS TO AFFECT THE
REGION...SHOULD THE MODELS PAN OUT...WOULD COME MONDAY THROUGH
WEDNESDAY OF NEXT WEEK. THE FIRST OF THESE LATE PERIOD SYSTEMS IS
PROGGED TO ORIGINATE OVER THE GULF OF MEXICO AND MOVE UP THE EASTERN
SLOPES OF THE APPALACHIAN MOUNTAINS MONDAY AND MONDAY NIGHT. THE
SECOND WEATHER SYSTEM IN THIS SCENARIO IS FORECAST TO TAKE SHAPE
OVER THE NORTHERN PLAINS TO BEGIN THE NEW WORK WEEK. THIS SECOND
SYSTEM WOULD COME IN THE FORM OF A LARGE SCALE AND MUCH DEEPER
TROUGH THAN EITHER OF THE SOUTHERN STREAM SYSTEMS. THIS AREA OF LOW
PRESSURE WOULD PROVIDE THE SOURCE OF COLD AIR THAT COULD BRING SUB
FREEZING TEMPERATURES AND SNOW NEXT WEDNESDAY NIGHT.
THE UNCERTAINTY WITH THIS WEEKENDS WEATHER WILL REVOLVE AROUND HOW
MUCH COLD AIR WILL BE ABLE TO FILTER INTO THE AREA AS THE SOUTHERN
PLAINS LOW MAKES ITS NORTHEASTERN TURN FRIDAY NIGHT. BASED ON THE
LATEST MODEL SOUNDINGS AND TIME HEIGHTS...THERE IS SOME UNCERTAINTY
AS TO HOW FAR SOUTH THE COLD AIR WILL PENETRATE FRIDAY NIGHT INTO
SATURDAY MORNING. BASED ON THIS...DECIDED TO CONFINE ANY
ACCUMULATING SNOW TO THE AREA NORTH OF THE MOUNTAIN PARKWAY BETWEEN
6 AND 12Z FRIDAY NIGHT. THE SNOW SHOULD THEN TRANSITION TO A RAIN
SNOW MIX EARLY SATURDAY MORNING...AND THEN TO ALL RAIN BY EARLY
SATURDAY AFTERNOON. ANY SNOW ACCUMULATIONS THAT DO OCCUR WOULD
LIKELY BE CONFINED TO GRASSY AREAS AND ELEVATED SURFACES. OUR FAR
EASTERN COUNTIES COULD SEE ANOTHER SHOT OF RAIN SNOW MIX OR ALL SNOW
FOR A BRIEF PERIOD SATURDAY NIGHT AS THE LOW EXITS THE AREA AND
WINDS SHIFT TO THE NORTH NORTHEAST. A WEAK RIDGE OF HIGH PRESSURE
ALOFT SHOULD PROVIDE A BRIEF RESPITE FROM THE WINTRY WEATHER LATE
SATURDAY NIGHT THROUGH MID MORNING ON SUNDAY. THE MODELS ONCE AGAIN
OFFER UP SOME UNCERTAINTY AS TO EXACTLY WHEN PRECIPITATION ONSET
WILL BE ON SUNDAY...WITH THE GFS MODEL HOLDING OFF A LOT LONGER THAN
THE ECMWF. BASED ON THIS...WENT WITH A BLEND BETWEEN THE TWO MODELS
FOR PRECIP ONSET ON SUNDAY ACROSS OUR EASTERN COUNTIES...WITH LIGHT
RAIN AFFECTING THE SOUTHEASTERN TWO THIRDS OF THE AREA AS MOISTURE
FROM THE GULF LOW BEGINS TO MOVE NORTHWARD INTO THE AREA. THE BETTER
SHOT OF PRECIPITATION WILL COME FROM MONDAY NIGHT THROUGH WEDNESDAY
EVENING...AS A MUCH STRONGER AND WETTER WEATHER SYSTEM DIVES OUT OF
THE NORTHERN PLAINS AND PHASES WITH WHAT EVER ENERGY IS LEFT OVER
FROM THE GULF OF MEXICO WEATHER SYSTEM. MOST OF THE PRECIPITATION
WITH THIS THIRD WEATHER SYSTEM LOOKS TO BE IN THE FORM OF RAIN BASED
ON THE TEMPERATURE PROFILES SEEN IN THE LATEST MODEL DATA. COULD SEE
SOME MORE SNOW WITH THIS FINAL WEATHER SYSTEM AS WINDS SHIFT TO THE
WEST AND NORTHWEST BEHIND THE LOW AS IT MOVES INTO NEW ENGLAND AND
COLDER AIR SPILLS INTO THE REGION.
THE OTHER WEATHER CONCERN OF NOTE FOR THE END OF THE EXTENDED PERIOD
WILL BE WINDS...PARTICULARLY FROM WEDNESDAY ONWARD. THE MODELS ALL
AGREE THAT A WELL DEVELOPED PRESSURE GRADIENT WILL ACCOMPANY THE
GREAT PLAINS WEATHER SYSTEM AS IT MOVES EAST. SUSTAINED WEST TO
NORTHWEST WINDS OF 10 TO 15 MPH...WITH GUSTS OF 20 TO 25 MPH...WILL
NOT BE OUT OF THE QUESTION. TEMPERATURES THROUGHOUT THE EXTENDED
PERIOD LOOK TO BE AT OR SLIGHTLY ABOVE NORMAL FROM SUNDAY THROUGH
WEDNESDAY. THE WARMEST STRETCH DURING THAT TIME WOULD BE MONDAY AND
TUESDAY...AS WINDS SHIFT TO THE SOUTH AHEAD OF THE MID WEEK WEATHER
SYSTEM. HIGHS ON EACH OF THOSE DAYS ARE EXPECTED TO TOP OUT IN THE
UPPER 40S AND LOWER 50S RESPECTIVELY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1245 AM EST THU DEC 18 2014
HIGH PRESSURE OVERHEAD IS KEEPING A STRONG SUBSIDENCE INVERSION IN
PLACE ACROSS MUCH OF THE NORTHERN HALF OF THE CWA...TRAPPING LOW LEVEL
MOISTURE AND RESULTING IN OVC MVFR CIGS...INCLUDING AT KSJS AND KSYM
/AND IMPOSING ON KJKL FAIRLY QUICKLY/. MEANWHILE...A WEAK UPPER LEVEL
DISTURBANCE IS MOVING INTO THE MISSISSIPPI RIVER VALLEY...SPREADING
AN AREA OF HIGH CLOUDS OUT AHEAD OF IT. EXPECT THE SOUTHWARD
PROGRESSION OF THE LOW CLOUDS TO BE STOPPED BY THE INCOMING
DISTURBANCE...AND MVFR CIGS TO SIT IN PLACE OVER THE AFFECTED TAF
SITES THROUGH THE REMAINDER OF THE NIGHT. MODELS ARE STILL SHOWING
THIS DISTURBANCE BRINGING A CHANCE OF LIGHT PRECIP TO KSYM AND KLOZ.
HOWEVER...GIVEN THE STRONG SURGE OF LOW LEVEL DRY AIR IN THIS AREA /WHERE
LOW LEVEL CLOUD COVER HAS NOT BEEN A FACTOR/...IT WILL BE HARD FOR
ANY PRECIP TO REACH THE GROUND. MAY NOT RULE OUT SOME SPRINKLES OR
FLURRIES AS CIGS LOWER TO AROUND 5 TO 7K FT BETWEEN 10 AND 14Z THIS
MORNING...BUT GIVEN LOW CONFIDENCE AND MINIMAL IMPACTS...DID NOT
INCLUDE IN TAFS AT THIS TIME. ANY LINGERING LOW LEVEL CLOUDS LOOK TO
BREAK BETWEEN 15 AND 18Z TODAY. OTHERWISE...WHILE WESTERLY WINDS
ALOFT CONTINUE TO BE VERY STRONG...EXPECT LIGHT AND VARIABLE WINDS
WITHIN THE FIRST FEW THOUSAND FEET AGL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JMW
LONG TERM...AR
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
1245 AM EST THU DEC 18 2014
.UPDATE...
ISSUED AT 1050 PM EST WED DEC 17 2014
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT TRENDS IN OBSERVATIONS
AND SATELLITE IMAGERY. STRATOCU HAS REDEVELOPED OVER THE SOUTHEASTERN
COUNTIES AND IS SPREADING BACK SOUTH ACROSS NORTHEASTERN KY AS WELL.
AS THE MID AND HIGH CLOUDS GRADUALLY ADVANCE IN FROM THE SOUTHWEST
CONFIDENCE IN THIS LOW DECK IS NOT EXTREMELY HIGH...BUT CLOUDS WILL
GRADUALLY INCREASE. WITH THE CLOUD FORECAST BEING LOW CONFIDENCE...IT
ALSO LEADS TO A TRICKY HOURLY TEMPERATURE FORECAST. MANY VALLEY
LOCATIONS THAT ARE CLOUD FREE ARE IN THE MID AND UPPER 20S AND MAY
DROP A COUPLE MORE DEGREES DURING BREAKS IN THE CLOUDS AND WHERE
CLOUDS DO NOT INCREASE FOR A FEW MORE HOURS. RECENT HRRR RUNS SUPPORT
A SLIGHTLY HIGHER CHANCE FOR LIGHT PRECIPITATION IN THE SOUTHWEST
REACHING THE GROUND NEAR DAWN AND OVERCOMING DRY AIR CENTERED NEAR
850 MB. THIS WOULD PROBABLY FALL AS ALL SNOW DUE TO WETBULBING. THIS
WOULD MAINLY BE FOR THE LAKE CUMBERLAND REGION COUNTIES OF WAYNE AND
MCCREARY AND POSSIBLY EXTENDING INTO ADJACENT PARTS OF SOUTHERN
PULASKI... SOUTHWEST LAUREL AND WESTERN WHITLEY COUNTIES.
OTHERWISE...THE LOW LEVELS SHOULD REMAIN TOO DRY FOR ANYTHING MORE
THAN VIRGA OR SOME STRAY FLURRIES OR SPRINKLES ON THU...BUT THERE
WILL BE PLENTY OF CLOUDS.
UPDATE ISSUED AT 815 PM EST WED DEC 17 2014
HOURLY GRIDS HAVE BEEN ADJUSTED TO ACCOUNT FOR THE CLEARING SOUTH OF
THE INTERSTATE 64 CORRIDOR AND HOURLY TEMPERATURE TRENDS. SOME
LOCATIONS SUCH AS JKL AND SME AS WELL AS VALLEY LOCATIONS ARE RUNNING
BELOW THE PREVIOUS FORECAST SO THE FIRST FEW HOURS WERE TRENDED
ACCORDINGLY ALTHOUGH MIN T FOR THE REST OF THE NIGHT WAS UNCHANGED FOR
MOST LOCATIONS. LIGHT PRECIP OR VIRGA WILL APPROACH THE SW PART OF THE
CWA TOWARD DAWN...BUT WILL BE STRUGGLING TO OVERCOME SIGNIFICANT LOW
LEVEL DRY AIR.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 310 PM EST WED DEC 17 2014
19Z SFC ANALYSIS SHOWS HIGH PRESSURE STARTING TO MORE EFFECTIVELY
MOVE INTO THE AREA. THIS IS BEGINNING TO BREAK UP THE LOW LEVEL CLOUD
COVER ACROSS AT LEAST THE SOUTHERN HALF OF THE CWA. THESE CLOUDS HAVE
KEPT TEMPERATURES IN CHECK SO FAR TODAY WITH READINGS GENERALLY IN
THE MID TO UPPER 30S NORTH AND IN THE LOWER 40S IN THE SOUTHEAST
WHERE SOME EARLY SUNSHINE IS MAKING ITS PRESENCE FELT. DEWPOINTS HAVE
DRIED OUT THROUGH THE DAY AND ARE NOW IN THE UPPER 20S TO LOWER 30S.
WINDS HAVE BEEN RELATIVELY LIGHT GENERALLY FROM THE WEST AT 5 TO 10
KTS TODAY.
THE MODELS ARE NOW IN PRETTY GOOD AGREEMENT ALOFT THROUGH THE SHORT
TERM PORTION OF THE FORECAST. THEY ALL DEPICT THE CLOSED...BUT
PROGRESSIVE...UPPER LOW THAT WILL SKIRT EAST THROUGH THE LOWER GREAT
LAKES THIS EVENING AND OVERNIGHT. A BRIEF PERIOD OF RIDGING WILL
FOLLOW INTO THURSDAY MORNING FOR EASTERN KENTUCKY BEFORE A RATHER
DAMPENED WAVE MOVES THROUGH LATER IN THE DAY AND THAT NIGHT WITH
SOME WEAK MID-LEVEL ENERGY FLOWING INTO THE CONFLUENCE ZONE EAST OF
THE AREA. WITH THE GENERAL MODEL AGREEMENT HAVE FOLLOWED THE HIGH
RESOLUTION NAM12 AND HRRR MOST CLOSELY FOR WEATHER DETAILS.
SENSIBLE WEATHER WILL FEATURE A BRIEF TIME OF CLEARING THIS EVENING
AND INTO TONIGHT THAT SHOULD ALLOW FOR SOME DECENT RADIATIONAL
COOLING AND RIDGE TO VALLEY TEMPERATURE DIFFERENCES THROUGH MIDNIGHT.
THEREAFTER...HIGH AND MID LEVEL CLOUDS WILL RETURN TO THE AREA FROM
WEST TO EAST AND PUT A CAP ON THE COOLING...LIMITING FURTHER TERRAIN
DIFFERENCES FOR THE REST OF THE NIGHT. THESE CLOUDS WILL ATTEMPT TO
BRING SNOW TO THE SOUTHWESTERN PARTS OF THE AREA BEFORE DAWN...BUT IT
WILL HAVE TO OVERCOME THE DRYING TAKING PLACE ATTM. ACCORDINGLY...
HAVE UNDERCUT QPF AND POPS FROM THE NAM/MET FOR LATE TONIGHT INTO
THURSDAY MORNING. THE AREA OF LOW PRESSURE RESPONSIBLE FOR THE PCPN
THREAT WILL DAMPEN THROUGH THE MORNING AND FADE OUT BY AFTERNOON. FOR
THIS...HAVE LIMITED THE PCPN THREAT TO JUST FLURRIES AND SPRINKLES
FOR THE SECOND HALF OF THE DAY. ADDITIONAL MOISTURE WILL PASS BY TO
THE NORTH LATER THAT EVENING AND A FEW FLURRIES WILL BE POSSIBLE FROM
THIS ALONG WITH ANOTHER COOL NIGHT.
AGAIN USED THE BCCONSSHORT AS A STARTING POINT FOR THE T/TD/WIND
GRIDS FOR THE FIRST 20 HOURS OR SO BEFORE POPULATING WITH THE
SUPERBLEND THEREAFTER. MINOR ADJUSTMENTS WERE MADE FOR TERRAIN
EFFECTS BOTH TONIGHT AND THURSDAY NIGHT. AS FOR POPS...ENDED UP A BIT
UNDER THE MET NUMBERS AND CLOSER TO THE DRIER MAV ONES FOR TONIGHT
AND THURSDAY GIVEN THE DRY AIR THAT WILL BE IN PLACE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 340 PM EST WED DEC 17 2014
FORECAST MODELS ARE IN GOOD AGREEMENT ON AN ACTIVE WEATHER PATTERN
WITH AT LEAST TWO SYSTEMS TO AFFECT US THROUGH THE PERIOD.
THE FIRST STORM OVER THE WEEKEND CONTINUES TO LOOK RATHER WEAK. A
LIGHT RAIN/SNOW MIX WILL MOVE INTO THE AREA OVERNIGHT FRIDAY NIGHT.
THIS WILL CHANGE TO ALL RAIN DURING THE DAY ON SATURDAY...FOLLOWED
BY PERHAPS BY A LITTLE MORE SNOW AS THE PRECIPITATION ENDS SATURDAY
NIGHT. THERE IS JUST NOT A LOT OF COLD AIR IN PLACE AND
PRECIPITATION LOOKS LIGHT SO ANY SNOW ACCUMULATIONS WILL BE VERY
LIGHT WITH THIS SYSTEM...IF ANY OCCUR AT ALL.
A MUCH MORE IMPRESSIVE STORM SYSTEM IS SHOWING UP IN THE COMPUTER
MODELS FOR THE MIDDLE OF NEXT WEEK...WITH DECENT AGREEMENT ON AN
IMPACTFUL SYSTEM JUST IN TIME FOR PEAK HOLIDAY TRAVEL. AN UPPER
LEVEL TROUGH WILL DIG IN OVER THE PLAINS EARLY IN THE WEEK AND
BECOME NEGATIVELY TILTED OVER THE OHIO VALLEY MID WEEK. THIS CAUSES
EXPLOSIVE DEEPENING OF A SURFACE LOW PRESSURE WHICH IS PROGGED TO
DEVELOP AND TRACK OVER US OR VERY CLOSE TO US ON ITS WAY NORTH TO
THE GREAT LAKES. THIS SYSTEM IS STILL WAY TOO FAR OUT IN THE FUTURE
TO PINPOINT EXACTLY WHAT TYPE OF WEATHER WE WILL BE DEALING
WITH...BUT RAIN...WIND AND SNOW ARE ALL ON THE TABLE FROM TUESDAY
THROUGH WEDNESDAY...AND POTENTIALLY BEYOND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1245 AM EST THU DEC 18 2014
HIGH PRESSURE OVERHEAD IS KEEPING A STRONG SUBSIDENCE INVERSION IN
PLACE ACROSS MUCH OF THE NORTHERN HALF OF THE CWA...TRAPPING LOW LEVEL
MOISTURE AND RESULTING IN OVC MVFR CIGS...INCLUDING AT KSJS AND KSYM
/AND IMPOSING ON KJKL FAIRLY QUICKLY/. MEANWHILE...A WEAK UPPER LEVEL
DISTURBANCE IS MOVING INTO THE MISSISSIPPI RIVER VALLEY...SPREADING
AN AREA OF HIGH CLOUDS OUT AHEAD OF IT. EXPECT THE SOUTHWARD
PROGRESSION OF THE LOW CLOUDS TO BE STOPPED BY THE INCOMING
DISTURBANCE...AND MVFR CIGS TO SIT IN PLACE OVER THE AFFECTED TAF
SITES THROUGH THE REMAINDER OF THE NIGHT. MODELS ARE STILL SHOWING
THIS DISTURBANCE BRINGING A CHANCE OF LIGHT PRECIP TO KSYM AND KLOZ.
HOWEVER...GIVEN THE STRONG SURGE OF LOW LEVEL DRY AIR IN THIS AREA /WHERE
LOW LEVEL CLOUD COVER HAS NOT BEEN A FACTOR/...IT WILL BE HARD FOR
ANY PRECIP TO REACH THE GROUND. MAY NOT RULE OUT SOME SPRINKLES OR
FLURRIES AS CIGS LOWER TO AROUND 5 TO 7K FT BETWEEN 10 AND 14Z THIS
MORNING...BUT GIVEN LOW CONFIDENCE AND MINIMAL IMPACTS...DID NOT
INCLUDE IN TAFS AT THIS TIME. ANY LINGERING LOW LEVEL CLOUDS LOOK TO
BREAK BETWEEN 15 AND 18Z TODAY. OTHERWISE...WHILE WESTERLY WINDS
ALOFT CONTINUE TO BE VERY STRONG...EXPECT LIGHT AND VARIABLE WINDS
WITHIN THE FIRST FEW THOUSAND FEET AGL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...ABE
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
403 AM EST THU DEC 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM EST THU DEC 18 2014
AN UPPER RIDGE STRETCHING FROM MINNESOTA THROUGH NORTHWEST ONTARIO
WILL BE THE MAIN FEATURE CONTROLLING THE WEATHER OVER THE UPPER
GREAT LAKES REGION OVER THE NEXT 24 HOURS. BENEATH THIS UPPER
RIDGE...A 1029MB SURFACE HIGH SITS JUST TO THE NORTH OF THE
MINNESOTA WHILE THE SURFACE TROUGH THAT LED TO THE SNOW YESTERDAY
IS OVER NORTHERN LAKE MICHIGAN AND NORTHERN LOWER MICHIGAN AND
WEAKENING. NORTH-NORTHEASTERLY FLOW AROUND THIS HIGH HAS PULLED
DRIER AIR INTO THE UPPER GREAT LAKES REGION...LEADING TO CLEARING
SKIES THIS PAST EVENING OVER MUCH OF LAKE SUPERIOR. BUT MOISTURE
TRAPPED BELOW THE SUBSIDENCE INVERSION...AND COMBINED WITH UPSLOPE
FLOW...HAS LED TO LOW CLOUDS PERSISTING OVER A GOOD PORTION OF
UPPER MICHIGAN EARLY THIS MORNING. THERE ARE A COUPLE SPOTS WHERE
THE CLOUDS DID CLEAR OUT...GENERALLY OVER THE KEWEENAW PENINSULA
AND ALSO IT/S STARTING TO OVER THE EAST. WHERE SKIES CLEARED
OUT...3AM TEMPERATURES ARE IN THE SINGLE DIGITS ABOVE ZERO (6
DEGREES AT KCMX)...WHILE THE CLOUDS HAVE KEPT THE TEMPERATURES IN
THE UPPER TEENS AND LOWER 20S ELSEWHERE. STILL SEEING LIGHT
FLURRIES HERE AT OUR OFFICE AT 330AM...SO WILL CONTINUE TO MENTION
ISOLATED FLURRIES IN THE FORECAST FOR THE UPSLOPE LOCATIONS THROUGH
DAYBREAK.
WITH THE UPPER RIDGE AND SURFACE HIGH MOVING OVER THE AREA
TODAY...EXPECT CONTINUED QUIET CONDITIONS FOR THE SHORT TERM
PERIOD. THERE ARE TWO AREAS OF FOCUS IN THE SHORT TERM
PERIOD...FIRST THE LOW CLOUDS AND THEIR DIMINISHMENT AND THEN THE
POTENTIAL FOR SOME FREEZING FOG OVERNIGHT TONIGHT. FOR THE LOW
CLOUDS...KMQT VWP INDICATES CLOUD TOPS AROUND 2.5KFT...WHICH
MATCHES UP WELL WITH THE INVERSION INDICATED ON THE MODELS AT
900MB. THE BIG QUESTION IS WHEN WILL THEY DISSIPATE TODAY. AT
THIS TIME OF THE YEAR WITH THE LOW SUN ANGLE AND LIMITED
MIXING...THERE IS LITTLE DAY TIME HELP AND WILL NEED TO RELY ON THE
ADVECTION OF DRIER AIR INTO THE AREA. UNFORTUNATELY...THIS IS WHERE
THE MODELS TEND TO DIFFER. THE 00Z NAM HOLDS ONTO THE CLOUDS FOR
MUCH OF THE DAY AND EVEN THROUGH THE NIGHT TONIGHT...BUT THINK THAT
IS LARGELY TIED TO IT TRADITIONALLY OVER DOING LOW LEVEL MOISTURE.
THAT APPEARS TO THE CASE EARLY THIS MORNING...WHERE IT HAS THE LOW
CLOUDS JUST TO THE WEST OF JAMES BAY BEING MUCH FARTHER TO THE
SOUTH AND SUPPOSEDLY ENTERING NORTHERN LAKE SUPERIOR AT THIS TIME.
THE RECENT RAP (ALONG WITH THE HRRR) RUNS ALSO HOLD ONTO THE CLOUDS
FOR MUCH OF THE DAY BEFORE CLEARING THEM OUT THIS AFTERNOON...BUT IT
APPEARS TO HAVE THE LOW LEVEL MOISTURE FARTHER NORTH OVER LAKE
SUPERIOR THAN WHAT IS ACTUALLY OCCURRING. THE MORE OPTIMISTIC
RUNS...WHICH SEEM TO HAVE A BETTER HANDLE ON THE LOCATION OF THE
LOW CLOUDS ARE THE 00Z GFS/ECMWF. THEY HOLD ONTO THE LOW CLOUDS
OVER THE NORTH CENTRAL AND WEST FOR THE FIRST PART OF THE MORNING
AND THEN SCATTER THEM OUT THROUGH THE LATER PART OF THE MORNING AND
EARLY AFTERNOON. WILL FOLLOW THAT IDEA AT THIS POINT FOR THE CLOUD
COVER FORECAST FOR TODAY. MEANWHILE OVER THE EAST...THE ADVECTION
OF THE DRIER AIR AND LITTLE UPSLOPE HELP SHOULD ALLOW THE LOW
CLOUDS TO DISSIPATE DURING THE FIRST PART OF THE MORNING. THAT DRY
AIR HAS ALREADY SCATTERED THE CLOUDS OUT OVER LUCE COUNTY AND
STARTING TO SEE IT WORK INTO ALGER/SCHOOLCRAFT COUNTIES. AS FOR
HIGHS TODAY...EXPECT THEM TO BE IN THE MID-UPPER 20S OVER MUCH OF
THE AREA.
FOLLOWING THE IDEA OF THE CLOUDS DIMINISHING TODAY...WOULD EXPECT A
VERY GOOD RADIATIONAL COOLING NIGHT TONIGHT UNDER THE CENTER OF THE
HIGH. THUS...WILL CONTINUE THE IDEA OF GOING AT OR BELOW THE
COLDEST GUIDANCE. THE GEM MODELS USUALLY PERFORM WELL IN
RADIATIONAL COOLING NIGHTS AND THEY HAVE LOWS IN THE LOWER SINGLE
DIGITS WHERE THEY ARE NOT INDICATING CLOUDS (ALTHOUGH THE REGIONAL
GEM REDEVELOPS LOW CLOUDS OVER THE HIGHER TERRAIN OF THE NORTH
CENTRAL TONIGHT). THUS...HAVE LOWS IN THE SINGLE DIGITS ABOVE ZERO
TO AROUND ZERO OVER THE INTERIOR LOCATIONS. WITH KCMX DROPPING TO 6
DEGREES AT 3AM THIS MORNING...THAT SUPPORTS TO EXPECTATIONS FOR
TONIGHT. THIS EXPECTED DROP IN TEMPS WILL LEAD TO THE POTENTIAL FOR
PATCHY FREEZING FOG OR AT LEAST SOME SOLID FROST. WITH DEWPOINTS IN
THE MID-UPPER TEENS TODAY...TEMPS SHOULD EASILY DROP THROUGH THOSE
VALUES THIS EVENING. DEWPOINTS THIS PAST EVENING AT KCMX WERE
SIMILAR TO WHAT IS EXPECTED ACROSS THE REST OF THE AREA THIS
AFTERNOON. WITH THEIR QUICK TEMP DROP AND LIGHT WINDS...THEY HAVEN/T
EXPERIENCED ANY FOG AT THIS POINT...BUT THE ICE ACCRETION ALGORITHM
DID INDICATE SOME ICE ACCUMULATION. THIS IS LIKELY DUE TO THAT QUICK
DROP AND IN TURN SOME QUICK/HARD FROST ON THE SENSOR. IT WILL BE
INTERESTING TO SEE IF ANY VERY SHALLOW FOG DEVELOPS AT KCMX OVER
THE NEXT COUPLE HOURS...AS IT WILL FORESHADOW WHAT WILL OCCUR
TONIGHT.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 354 PM EST WED DEC 17 2014
QUIET WEATHER IS EXPECTED THROUGH THE WEEKEND BEFORE AN ACTIVE
PATTERN DEVELOPS ACROSS THE GREAT LAKES REGION NEXT WEEK. THIS
INCLUDES THE POTENTIAL FOR A DISRUPTIVE SYSTEM LATE TUESDAY INTO
CHRISTMAS DAY.
THURSDAY NIGHT THROUGH SUNDAY...MID-LEVEL RIDGING STRETCHING FROM
THE NORTHERN PLAINS INTO NORTH-CENTRAL CANADA TODAY WILL BE DRIFTING
EASTWARD ACROSS THE UPPER GREAT LAKES AT THE BEGINNING OF THE
PERIOD. THE ASSOCIATED SFC RIDGE AXIS IS FORECAST TO BE OVER UPPER
MI THURSDAY NIGHT...SETTING THE STAGE FOR A RATHER CHILLY NIGHT.
DRIER AIR FILTERING IN FROM THE NORTH ON THURSDAY WILL SLOWLY ERODE
CLOUDS TRAPPED UNDER A 1-2KFT INVERSION. VEERING SFC WINDS MAY BRING
LOW CLOUDS BACK INTO THE AREA...BUT NOT UNTIL LATER THURSDAY NIGHT.
WITH A RELATIVELY FRESH SNOW PACK AND LIGHT WINDS...TEMPS LOOK TO
FALL TO NEAR ZERO FOR INTERIOR LOCATIONS TO THE MID TEENS FOR
SHORELINE LOCATIONS. WENT BELOW NEARLY ALL GUIDANCE. FREEZING FOG
WILL BE A POSSIBILITY FOR THE WEST AND CENTRAL INTERIOR FROM THE
GOOD RADIATIONAL COOLING AND RESIDUAL SFC MOISTURE UNDER THE
SHALLOW INVERSION.
AFTER A MOSTLY SUNNY DAY FOR AT LEAST THE EAST HALF ON
FRIDAY...CLOUDS WILL GRADUALLY INCREASE FROM THE WEST AS A WEAK
SHORTWAVE TROUGH ALONG THE U.S./CANADIAN BORDER MOVES TOWARD THE
UPPER GREAT LAKES. WITH LITTLE FORCING AND ONLY MODEST
MOISTURE...ONLY CLOUDS ARE EXPECTED FOR SATURDAY AND SUNDAY.
SUNDAY NIGHT THROUGH WEDNESDAY...A RATHER EXTENDED PERIOD OF
UNSETTLED WEATHER IS EXPECTED TO BEGIN BY THIS POINT. A SECONDARY
TROUGH DIGGING INTO THE NORTHERN HIGH PLAINS ON SATURDAY WILL
REINFORCE THE DECAYING LEAD TROUGH OVER THE UPPER MS VALLEY BY
SUNDAY AFTERNOON. LOW-LEVEL WAA AND FGEN COMBINED WITH DEEPER
MOISTURE AND MID-LEVEL FORCING WILL BE ENOUGH TO INDUCE SOME LIGHT
PRECIP ACROSS THE CWA LATE SUNDAY AFTERNOON INTO MONDAY. THERE IS
SOME DIFFERENCE ON HOW THE MODELS HANDLE THE PHASING OF THE TROUGHS
AT THIS POINT...WITH THE 12Z GFS SHOWING A SOMEWHAT STRONGER
SOLUTION. EITHER WAY...DEEPER MOISTURE WILL BE ADVECTING INTO THE
REGION...BUT WILL BE LESS THAN IDEAL FOR WIDESPREAD PRECIP. WILL
KEEP THE CONSENSUS BLEND OF CHANCE POPS FOR MUCH OF THE CWA LATE
SUNDAY AFTERNOON THROUGH MONDAY.
A LOT OF UNCERTAINTY GETS INFUSED INTO THE FORECAST BEGINNING MONDAY
NIGHT AS A THIRD...QUICK-MOVING...SHORTWAVE TRACKS ESE OUT OF THE
PACIFIC NW. HOW THIS TROUGH INTERACTS WITH THE EXISTING TROUGHS OVER
THE UPPER GREAT LAKES IS RATHER UNCLEAR AT THIS TIME. HOWEVER...THE
CONGLOMERATION OF THE TROUGHS WILL INDUCE A STRONG SFC LOW OVER THE
REGION BY CHRISTMAS EVE. BOTH THE ECMWF AND GFS ARE ADVERTISING A
LOW AS DEEP AS 960MB OVER LAKE HURON WEDNESDAY EVENING.
WHILE WIDESPREAD SNOW LOOKS FAIRLY CERTAIN MONDAY NIGHT INTO
CHRISTMAS...THE INTENSITY WILL REMAIN IN QUESTION FOR SOME TIME AS
GUIDANCE IS MIXED ON HOW THE SYNOPTIC PRECIP PATTERNS EVOLVE. ALL
THE LONG RANGE MODELS BRING ENERGY FROM THE FIRST TWO SHORTWAVES
NORTHEASTWARD ACROSS THE REGION LATE MONDAY NIGHT INTO TUESDAY. THIS
WOULD RESULT IN A QUICK ROUND OF MODERATE WET SNOW DURING THAT TIME
PERIOD.
TUESDAY NIGHT INTO WEDNESDAY MORNING MAY HAVE A BRIEF LULL IN PRECIP
BEFORE THE RAPIDLY DEEPENING LOW QUICKLY MOVES NORTHWARD OUT OF THE
OHIO VALLEY. THIS WOULD BRING INCREASING CHANCES OF MODERATE TO
HEAVY SNOW BY WEDNESDAY NIGHT. HOWEVER...LOW-LEVEL CAA WILL LAG THE
MAIN SYNOPTIC MOISTURE...REDUCING LAKE-ENHANCEMENT. EITHER WAY...A
1030MB HIGH PUSHING IN ON THE BACKSIDE OF THE LOW WILL RESULT IN
STRONG N/NNW WINDS BEGINNING WEDNESDAY AFTERNOON. WITH LAKE
EFFECT KICKING IN AS COLDER AIR FINALLY ARRIVES...CONDITIONS COULD
BE QUITE POOR FOR TRAVEL CHRISTMAS DAY.
SIMPLY PUT...THE SYSTEM LOOKS LIKE A DRAWN-OUT MESS FOR THE UPPER
GREAT LAKES TUESDAY INTO CHRISTMAS. STAYED TUNED...AS PLENTY OF
FORECAST CHANGES WILL LIKELY OCCUR OVER THE NEXT SEVERAL DAYS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1224 AM EST THU DEC 18 2014
SKIES HAVE ALREADY CLEARED OUT AT KCMX AS DRY AIR ARRIVES FROM THE
NORTH. LINGERING FLURRIES WILL END EARLY THIS MORNING AT KIWD AND
KSAW...BUT LOW MVFR CIGS SHOULD REMAIN AS MOISTURE IS TRAPPED BELOW
STRENGTHENING INVERSION. EXPECT SKIES TO GRADUALLY CLEAR AT BOTH
SITES BY THIS AFTERNOON DUE TO MIXING OUT OF THE SHALLOW MOIST
LAYER. RISK OF FREEZING FOG TONIGHT AT MAINLY KSAW AND POSSIBLY
KCMX. DID LEAVE OUT OF TAFS ATTM THOUGH AS GREATEST CHANCE OF VSBY
REDUCTION AND ICE DEPOSITION SHOULD NOT OCCUR UNTIL AFTER END OF TAF
PERIOD LATER ON THURSDAY NIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 403 AM EST THU DEC 18 2014
HIGH PRESSURE BUILDING INTO THE UPPER GREAT LAKES REGION TODAY AND
TONIGHT WILL DIMINISH THE NORTHERLY WINDS BELOW 15KTS. THE HIGH
WILL BEGIN TO SHIFT TO THE EAST OF THE REGION ON FRIDAY AND ALLOW
WINDS TO GRADUALLY TURN TO THE SOUTH THROUGH FRIDAY NIGHT. A NEARLY
STATIONARY TROUGH IN THE LEE OF THE NORTHERN ROCKIES THIS WEEKEND
WILL KEEP THE SOUTH TO SOUTHWESTERLY WINDS IN PLACE AND GENERALLY
UNDER 20KTS. THIS TROUGH WILL GIVE WAY TO A DEVELOPING LOW THAT
WILL MOVE INTO THE NORTHERN PLAINS SUNDAY NIGHT AND THE UPPER
MISSISSIPPI VALLEY ON MONDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KLUBER
AVIATION...JLA
MARINE...SRF
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
320 PM CST Tue Dec 16 2014
.SHORT TERM: (Through Friday Afternoon)
Issued at 320 PM CST Tue Dec 16 2014
(Tonight)
Deep cyclonic flow and cold air advection in the wake of yesterday`s
storm system kept diurnal temperature rises minimal today. Solid
shield of stratus yielded an occasional period of drizzle or
flurry, but nothing measurable was observed.
Cloud trends for tonight are uncertain. An extensive area of stratus
was located upstream, and northwest winds near 925mb remain
favorable for continued advection of these clouds into our area. On
the other hand, a hole was located in the cloud deck over western
IA, and if this area does not fill in, then skies should start to
clear over the Columbia and St. Louis areas between 23-02z. RAP
plots of increasing condensation pressure deficits between 975-900mb
tonight along with BUFKIT soundings which depict drying aloft both
support the idea of dissipating stratus/stratocu this evening,
although mid/high clouds will be increasing later tonight regardless
of what happens with the stratus/stratocu. However, BUFKIT profiles
also show a fair amount of subsidence above the low cloud layer,
which may act to trap moisture below the inversion and keep the
clouds in place. Partial clearing appears more likely over central
MO than elsewhere. Winds should remain around 10 kts for most of the
night.
CVKING/Kanofsky
(Wednesday - Friday)
Deep trof of low pressure currently coming onshore along the west
coast with our eyes tracking a pair of circulations that will bring
two chances of precipitation to the area the next seven days.
The first circulation will come ashore along the Baja tonight and
lift northeast across the southwest CONUS and southern Plains on
Wednesday. Warm advection will ramp up across the area Wednesday
night with light snow expected to rapidly develop and move into the
area from the southwest. Models continue to "moisten" the forecast
with higher QPF noted. Have increased POP and expected snowfall
amounts with up to two inches now possible across central Missouri
and the eastern Ozarks and an inch into the western suburbs of the
St. Louis Metro Area. Unfortunately it appears that the snow will be
hitting the St. Louis area either right before or at rush hour
Thursday morning. Luckily, ground temperatures are relatively warm
and air temperatures should be in the upper 20s or lower 30s. The
hope is that impact on travel will be low with this event. Snow will
taper off during the morning hours on Thursday as the shortwave
lifts east of the area. Lingering low level moisture and rising
surface temperatures suggest drizzle will be possible in the
afternoon hours.
The second and more potent circulation of the two will dig even
further south across the Baja before lifting east/northeast across
the deep south on Friday. Meanwhile, a northern stream shortwave
will also be diving southeast across the Plains. Unfortunately for
the snow lovers these two systems don`t appear to fully phase until
they are east of the area. Some snow flurries or light snow will be
possible across the far southern CWA Friday afternoon.
CVKING
.LONG TERM: (Friday Night through Next Tuesday)
Issued at 320 PM CST Tue Dec 16 2014
Continuing with the late week system, models push the southern
system, which will be the main driver of pcpn, well to our south
with some interaction with a northern system still anticipated to
help bring perhaps some light pcpn well to the north into a good
part of our region for Friday night. PoPs remain low because of
concerns of measurability, with many locations perhaps tracing out
instead. Pcpn-types favor snow.
The northern system itself will not quite get thru the forecast area
until later on Saturday and maintained slight chances for that
reason.
Southerly flow at the low levels will then be seen for Sunday and
Monday, helping temps to at or above normal levels once again.
Heading towards the middle of next week, a longwave RIDGE will
attempt to re-establish itself over western North America in
imitation of the dominant pattern in November, with a strong
shortwave disturbance dropping down in NW flow and a developing
upper level TROF over the central CONUS. Look for increasing PoPs
for this period with temps beginning to drop back to below normal
once again.
Christmas could be pretty quiet across our region, taking a sneak
peak at the long range models. But it looks to only be a timing
issue, with one system leaving and another lurking about a day away,
so this could change very quickly given all of the typical timing
issues the models have this far out.
TES
&&
.AVIATION: (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1112 AM CST Tue Dec 16 2014
The primary forecast question for this set of TAFs is whether the
stratus will end during the next 24 hours. On one hand, there`s an
extensive area of stratus located upstream as well as northwest
winds which will continue advecting the clouds into MO/IL. On the
other hand, there`s also a hole in the aforementioned cloud bank,
and RAP forecasts (CPD) as well as BUFKIT soundings show
additional drying, which suggests that existing clouds should
start to dissipate and that it will be difficult for new clouds to
develop even within cyclonic flow. On the other other hand, the
cig/vis trend viewer in AVNFPS is evenly split on whether clouds
usually persist through 12z or become less likely after 04-06z,
depending on what conditions look like at 21z and 00z. In short,
there is a surprisingly high amount of uncertainty with the cig
forecast. This set of TAFs splits the difference and keeps MVFR
ceilings in place through 06-08z, but it`s equally likely that
ceilings could improve earlier than forecast or persist later than
forecast.
Specifics for KSTL: It`s equally likely that MVFR stratus could
persist beyond 12z or depart earlier around 06z. There might also
be a brief break between 23z-02z, depending on what happens with
the hole in the clouds over IA which was noted on satellite
imagery at TAF issuance. Regardless of what happens with the MVFR
stratus, increasing mid and high level clouds are expected after
12z.
Kanofsky
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 27 36 30 36 / 0 0 60 60
Quincy 23 34 24 32 / 0 0 20 50
Columbia 23 36 29 36 / 0 5 80 60
Jefferson City 23 36 29 37 / 0 5 80 60
Salem 27 36 30 36 / 0 0 30 60
Farmington 26 38 29 36 / 0 5 80 60
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
257 PM CST Tue Dec 16 2014
.SHORT TERM...(This Evening through Thursday)
Issued at 251 PM CST TUE DEC 16 2014
Surface high pressure over Kansas will shift east into the area
tonight. As this occurs remaining stratus field will be shunted
eastward with just high clouds in its wake. With the light winds
temperatures will drop into the lower to middle 20s for lows.
Short wave energy will cross the Four Corners region Wednesday
morning and will emerge across the central Plains late in the
afternoon. As this happens, low level isentropic upglide will
develop across the southern Plains and will shift northeast into
our region starting later in the afternoon. The low levels of the
atmosphere will be very dry to start off with, but our confidence
is increasing that the dry air will be overcome sooner rather than
later. First off, we may get into a jet coupling situation which
would enhance mid/upper level lift. Additionally, there will be
some weak instability that spreads into the region from the west.
This may result in some weak convective potential.
With that being said, we have moved up the start time of
precipitation. We are expecting it to start across southwest
Missouri from mid to late afternoon and then spread northeast
across the remainder of the Missouri Ozarks Wednesday evening.
Precipitation type remains a tough call. As initial wet-bulbing
takes place, we are expecting a mixture of rain, snow, and sleet
from Wednesday afternoon into Wednesday evening. The weak
instability will also aid in sleet potential. We did consider a
mention of thunder, but we would like to see a bit more in the way
of MUCAPE.
As wet-bulbing diminishes, the rain/snow line should initially set
up across far southwestern Missouri Wednesday evening. This
rain/snow line will then shift north and east later Wednesday
evening and especially Thursday morning. At its furthest north and
east point, the rain/snow line should end up somewhere across
central Missouri Thursday afternoon. Not to be forgotten is an
expected loss of cloud ice from late Wednesday night into Thursday
morning. This should result in a transition to at least patchy
drizzle with the continued potential of embedded pockets of light
snow/rain.
As for accumulations, we have nudged up snow amounts into the 1-2"
range along and north of the Highway 60 corridor. Amounts across
far southern Missouri (especially in the southwest) will be held
down due to warmer temperatures/more rain. The highest amounts are
expected to occur in the Truman to Lake of the Ozarks region.
Another item we will be monitoring is freezing drizzle potential
late Wednesday night into Thursday morning as we lose the cloud
ice. The greatest prospects for any freezing drizzle would be
along and north of a Pittsburg, Kansas to Bolivar to West Plains
line. If this forecast holds, a Winter Weather Advisory may be
required for portions of the area.
.LONG TERM...(Thursday Night through Tuesday)
Issued at 251 PM CST TUE DEC 16 2014
Any significant precipitation should be well to our east Thursday
night, though widespread low clouds and drizzle are expected to
be in place across the region. This scenario will continue through
Friday morning as well, with widespread, shallow moisture across
the area. Precipitation type is a bit tricky, with surface
temperatures likely to be just above freezing, and cloud ice
rather intermittent in nature. This suggests a mix of drizzle,
rain and snow, and if surface temperatures do happen to drop below
freezing in a few locations, perhaps a bit of freezing drizzle. At
this point, however, any impacts look to be quite minor.
By Friday morning, a shortwave is expected to be traversing the
Red River valley and Arklatex region, with a surface low/inverted
trough along the Gulf coast. Model trends have been decidedly
south with this system over the last few days, and that continued
with this morning`s 12Z model runs. Right now it still looks like
the southern third or so of the CWA will see some light
precipitation, though if the system moves any further south, even
this chance may dwindle. Temperatures should be warm enough during
the day Friday to support a rain/snow mix, with any lingering
precipitation ending as all snow Friday night. At this time it
appears that precipitation will be light enough to preclude any
measurable accumulations.
Seasonable and generally dry conditions are expected for most of
the weekend, with highs Saturday and Sunday in the 40s. The next
workweek looks to begin with temperatures around normal, though an
Arctic front looks to be setting up to our northwest by the end of
the forecast period, suggesting cooler temperatures by the middle
of next week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1136 AM CST TUE DEC 16 2014
For the KSGF/KJLN/KBBG TAFS:
Main forecast concern is on cloud trends this afternoon and evening
and corresponding ceilings heights.
12Z KSGF sounding shows low level moisture in the 900mb-850mb layer.
Examinations of short term model trends indicates this layer to
slowly dry through the afternoon from west to east as surface high
pressure shifts eastward from Kansas. Visible satellite imagery
showing back edge of clouds into eastern Kansas. MVFR ceilings will
slowly rise at the taf sites before scattering out later this
afternoon. Of note is the 15Z RAP BUKFIT soundings are slower in
pushing this moisture out this afternoon. Based on latest
satellite trends feel RAP may be to slow. As high slides across
the terminals tonight into early Wednesday expect VFR conditions
with light winds. Mid level moisture begins to increase ahead of
the next wave between 15Z-18Z but any ceilings that develop will
be in the VFR range.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Raberding/Schaumann
LONG TERM...Boxell
AVIATION...Raberding
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1148 AM CST Tue Dec 16 2014
.SHORT TERM: (Through Late This Afternoon)
Issued at 326 AM CST Tue Dec 16 2014
Surface low currently over Quad Cities and will continue to lift
northeast today away from forecast area. Some lingering light
rain/drizzle to persist in wrap around this morning, mainly along
and east of Mississippi River. Otherwise, sc deck to be very slow to
move out of region, as high RH at 925mb remains entrenched over
forecast area today. As for temperatures, colder air to filter in
with temps still dropping a little this morning before becoming
steady or rise a few degrees by the early afternoon hours.
Byrd
.LONG TERM: (Tonight through Monday)
Issued at 326 AM CST Tue Dec 16 2014
It will remain mostly cloudy tonight with lows in the 20s. On
Wednesday we remain under surface ridge with partly cloudy skies and
highs in the mid 30s to low 40s.
Then the forecast for Wednesday night through Thursday is still
tricky to pin down. Surface ridge moves off to the east with upper
trof developing over southwestern US. Will see pieces of energy
eject out of trof and track through forecast area Wednesday night
and Thursday. We will remain in cold air so any precipitation that
does develop with these shortwaves will be in the form of light snow
for most of the area. QPF amounts will be on the light side with
highest amounts over southern sections of our forecast area. Could
see a few tenths of snowfall with highest amounts south of a
Columbia to Fredericktown line.
Beyond that, extended models still have differing solutions on
system that will remain south of forecast area Friday through
Saturday. GFS is a bit further north then ECMWF. For now will not
make major changes to pops through this period. As for pcpn type,
will cold air in place, should be all light snow.
Byrd
&&
.AVIATION: (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1112 AM CST Tue Dec 16 2014
The primary forecast question for this set of TAFs is whether the
stratus will end during the next 24 hours. On one hand, there`s an
extensive area of stratus located upstream as well as northwest
winds which will continue advecting the clouds into MO/IL. On the
other hand, there`s also a hole in the aforementioned cloud bank,
and RAP forecasts (CPD) as well as BUFKIT soundings show
additional drying, which suggests that existing clouds should
start to dissipate and that it will be difficult for new clouds to
develop even within cyclonic flow. On the other other hand, the
cig/vis trend viewer in AVNFPS is evenly split on whether clouds
usually persist through 12z or become less likely after 04-06z,
depending on what conditions look like at 21z and 00z. In short,
there is a surprisingly high amount of uncertainty with the cig
forecast. This set of TAFs splits the difference and keeps MVFR
ceilings in place through 06-08z, but it`s equally likely that
ceilings could improve earlier than forecast or persist later than
forecast.
Specifics for KSTL: It`s equally likely that MVFR stratus could
persist beyond 12z or depart earlier around 06z. There might also
be a brief break between 23z-02z, depending on what happens with
the hole in the clouds over IA which was noted on satellite
imagery at TAF issuance. Regardless of what happens with the MVFR
stratus, increasing mid and high level clouds are expected after
12z.
Kanofsky
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1136 AM CST Tue Dec 16 2014
.SHORT TERM...(Today and Tonight)
Issued at 330 AM CST TUE DEC 16 2014
A stacked low pressure system continued to make its way toward
the Great Lakes region this morning. Accompanying deep cyclonic
pattern was resulting in a an expansive stratus field from the
Ozarks north into the Canadian provinces. Some patchy drizzle or
sprinkles noted across the region this morning and this will
continue mainly across central Missouri through the early morning
hours. Clouds will linger most of the day with gradual clearing
from the west this afternoon into tonight.
.LONG TERM...(Wednesday through Monday)
Issued at 330 AM CST TUE DEC 16 2014
An active progressive pattern over the next several days will
bring the potential of a couple of chances of light winter
precipitation events.
Seasonably cool and tranquil can be expected during the day Wednesday
as surface high pressure builds across the area in the wake of the
exiting low pressure system. However the break in active weather
will be brief as a shortwave trough tracks from southern California
into the southern Plains by Wednesday night.
Theta-e advection within the 850-700 mb layer and isentropic ascent
will strengthen Wednesday evening as moisture advects northward
resulting in an increasing coverage of precipitation. Lift could
be further enhanced by a ribbon of mid level frontogenetical forcing.
Expect light precipitation to develop as early as late Wednesday afternoon
across far southwestern Missouri then overspread the area Wednesday
evening.
Top down winter precipitation method and progged thermal profiles
suggest that precipitation will be a mix of rain and snow across
far southern Missouri and extreme southeastern Kansas and
primarily all snow across the remainder of the area generally
north of Highway 60 Wednesday night. Surface temperatures will
settle to near the freezing mark across much the area.
Snow accumulations Wednesday night will be light with amounts
ranging from a trace up to an inch expected at this time. While
accumulations will be light there is the potential for travel
impacts Wednesday night into the Thursday morning commute.
Temperatures will rise above freezing Thursday while we lose cloud
ice. The result will be a transition Thursday to patchy light rain
and drizzle. Will have to monitor for the potential of patchy
freezing drizzle Thursday night.
The next more pronounced shortwave trough will track across Texas
and the lower Mississippi River Valley Friday and Saturday with a
developing surface low along the Gulf coast. The precipitation
shield associated with this system will brush southern Missouri
Friday and Friday night. Precipitation during the day Friday will
be primarily rain with some potential of a rain/snow mix. The best
chance of precipitation will be across south central Missouri
Friday night. Expect precipitation to transition to primarily snow
Friday night with the best potential of minor accumulations across
south central Missouri or southeast of a Branson to Salem line.
Overall confidence has increased that at least portions of the
Missouri Ozarks and extreme southeastern Kansas we will have a
couple of minor winter precipitation events Wednesday night again
later Friday. It is important to note that while accumulations if
any will be light there is the potential that travel could be
impacted Wednesday night into the Thursday morning commute and
again Friday night. The placement and accumulations of snow will
be refined with time as new model data is received. Please
monitor the latest forecast.
A seasonably cold and drier weather pattern will return this
weekend as the region comes under the influence of a more
northwesterly flow.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1136 AM CST TUE DEC 16 2014
For the KSGF/KJLN/KBBG TAFS:
Main forecast concern is on cloud trends this afternoon and evening
and corresponding ceilings heights.
12Z KSGF sounding shows low level moisture in the 900mb-850mb layer.
Examinations of short term model trends indicates this layer to
slowly dry through the afternoon from west to east as surface high
pressure shifts eastward from Kansas. Visible satellite imagery
showing back edge of clouds into eastern Kansas. MVFR ceilings will
slowly rise at the taf sites before scattering out later this
afternoon. Of note is the 15Z RAP BUKFIT soundings are slower in
pushing this moisture out this afternoon. Based on latest
satellite trends feel RAP may be to slow. As high slides across
the terminals tonight into early Wednesday expect VFR conditions
with light winds. Mid level moisture begins to increase ahead of
the next wave between 15Z-18Z but any ceilings that develop will
be in the VFR range.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Foster
LONG TERM...Foster
AVIATION...Raberding
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1120 PM CST WED DEC 17 2014
.SYNOPSIS...
ISSUED AT 325 PM CST WED DEC 17 2014
AN ACTIVE H5 PATTERN CONTINUES ACROSS THE LOWER 48 TDY
WITH NUMEROUS DISTURBANCES AND A CLOSED LOW NOTED OVER THE CONUS.
CLOSED LOW PRESSURE WAS NOTED OVER LAKE HURON AND EXTENDED WWD INTO
NRN WISCONSIN. HIGH PRESSURE WAS NOTED OVER NRN MANITOBA. ACROSS THE
WESTERN HALF OF THE CONUS...SHORTWAVES WERE NOTED OVER SERN
MT....SWRN NEW MEXICO...AND THE CALIFORNIA DESERT. HT FALLS OF 50 TO
70 METERS EXTENDED FROM EASTERN ARIZONA INTO SWRN KS. IN ASSOCIATION
WITH THE CLOSED LOW OVER THE GREAT LAKES...A NICE 50 TO 90 KT JET
STREAK EXTENDED FROM THE MID MISSOURI RIVER...EAST TO VIRGINIA AND
NORTH CAROLINA. HT FALLS IN ASSOCIATION WITH THE CLOSED LOW WERE
MOST PRONOUNCED OVER NEW ENGLAND...WHERE 50 TO 120 METER FALLS WERE
NOTED. AT THE SURFACE...ARCTIC HIGH PRESSURE WAS ANCHORED ACROSS THE
EASTERN DAKOTAS...SSE INTO MISSOURI. WEST OF THIS FEATURE...WEAK
SERLY WINDS WERE NOTED ALONG WITH PESKY LOW LEVEL CLOUDINESS AND
PATCHY FOG. TEMPERATURES THIS AFTERNOON WERE COLD WITH READINGS IN
THE LOWER 20S ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 325 PM CST WED DEC 17 2014
DESPITE THE MAIN UPPER PV ANOMALY AND ASSOCIATED LARGE SCALE FORCING
IS SOUTH OF THE AREA AND MOVING EASTWARD...SEVERAL FORECASTING
ISSUES REMAIN. THE STRATUS LAYER IS WARM ENOUGH TO CONTAIN
SUPERCOOLED LIQUID AND HENCE FALL TO THE GROUND IN WEAK UPSLOPE FLOW
AS FREEZING DRIZZLE IN SOME AREAS OF SOUTHWEST NEBRASKA THIS
AFTERNOON. RAP BUFR SOUNDINGS SUGGEST MINIMAL LIFT THROUGH THE
REMAINING AFTERNOON HOURS...BUT INCREASING SLIGHTLY THIS EVENING AND
OVERNIGHT. IR SAT PICS SHOW MID LEVEL CLOUDS TRYING TO MOVE OVER THE
TOP OF THE EXISTING LOW LEVEL STRATUS BUT HAVING A HARD TIME AS MID
LEVELS ARE QUITE DRY INITIALLY. BELIEVE THE INCREASING UPWARD
VERTICAL MOTION AS A RESULT OF WEAK MID LEVEL FRONTOGENESIS WILL
EVENTUALLY HELP TO MOISTEN THE MID LEVELS...BUT SOUNDINGS STILL SHOW
TOO MUCH DRY AIR TO CONNECT A SATURATED SNOW PRODUCING LAYER WITH
THE MOIST LOW LEVELS BELOW. THE END RESULT...BASED ON FORECAST
SOUNDINGS...WILL BE FREEZING DRIZZLE ESPECIALLY ACROSS THE SOUTHWEST
PORTION OF NEBRASKA THIS EVENING AND DURING THE OVERNIGHT. NEAR TERM
ENSEMBLES SUGGEST THE POSSIBILITY OF A SMALL BAND OF LIGHT SNOW FROM
SOUTHEAST FRONTIER COUNTY NORTHEASTWARD INTO CUSTER...BUT CONFIDENCE
IN SUCH A SMALL SCALE FEATURE BEING ABLE TO FULLY SATURATE THE
ATMOSPHERIC COLUMN TO SUPPORT LIGHT SNOW IS NOT HIGH...SO HAVE LEFT
PRECIPITATION MENTION AS FREEZING DRIZZLE FOR NOW.
FURTHER NORTH AND WEST...SOUTHERLY AND SOUTHEASTERLY WINDS WILL
CONTINUE TO SUSTAIN MOIST LOW LEVELS IN THE EASTERN PANHANDLE...BUT
MID AND UPPER LEVEL DRYING WILL BE GREATER HERE WHICH LEAVES A
BETTER SCENARIO FOR FOG AND HAVE THEREFORE INCLUDED THAT MENTION
THERE INTO THE MORNING HOURS. FOG WILL BE OCCURRING IN SNOW COVERED
AREAS WHICH WILL MEAN SOME DEPOSITION ON ROADS WILL BE POSSIBLE SO
THE MENTION OF FREEZING FOG WAS INCLUDED.
TOMORROW AFTERNOON CLOUDS WILL THIN ALTHOUGH STILL HAVE MUCH OF THE
AREA WITH A SNOW PACK. THIS WILL LIMIT THE ABILITY TO WARM...WITH
TEMPS STRUGGLING TO REACH FREEZING. SOME PARTIAL SUN IS EXPECTED
ACROSS WESTERN NEBRASKA THANKS TO SOME WESTERLY DOWNSLOPING WINDS
WHICH IS WHERE FORECAST HIGHS ARE THE WARMEST.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 325 PM CST WED DEC 17 2014
MID RANGE...THURSDAY NIGHT THROUGH SATURDAY...THE MAIN
FORECAST CHALLENGES IN THE MID RANGE ARE THE THREAT FOR FREEZING
DRIZZLE THURSDAY NIGHT INTO FRIDAY MORNING...AS WELL AS CLOUD COVER
AND TEMPERATURES. FOR THURSDAY NIGHT...WITH THE EXCEPTION OF THE FAR
NORTHWESTERN CWA...LOW CLOUDS AND AN ARCTIC DRAPE WILL REMAIN
ENTRENCHED ACROSS THE BULK OF THE FORECAST AREA. BOTH THE NAM AND
GFS SOLNS THIS MORNING PER FCST SOUNDINGS ARE INDICATING A NICE
LAYER OF NEAR 100 PERCENT RH FROM THE SURFACE TO 1000 TO 1500FT AGL.
WITHIN THIS LAYER...WEAK VEERING OF THE WINDS ARE PRESENT ALONG WITH
SOME WEAK OMEGA AND TEMPERATURES RANGING FROM ZERO TO -5C IN THIS
MOIST LAYER. IN ADDITION...WARMING AND DRYING IS INDICATED PER
FORECAST SOUNDINGS ABOVE THE MOIST LAYER DURING THE PERIOD. ALL
TOLD...THIS IS A DECENT SETUP FOR FREEZING DRIZZLE AND HAVE
INTRODUCED IT IN THE GRIDS. DURING THE EVENING HOURS...WITH THE
EXCEPTION OF THE PANHANDLE COUNTIES AND FAR NORTHWEST...CONDS WILL
BE FAVORABLE FOR FZDZ. THIS AREA WILL SHRINK EAST INTO THE OVERNIGHT
HOURS AND MORNING PERIOD FOR FRIDAY. BY FRIDAY AFTERNOON...MOSTLY
CLEAR SKIES IN THE CENTRAL AND WEST...AND PARTLY CLOUDY SKIES IN THE
EAST ARE EXPECTED. THIS WILL ALLOW TEMPS TO REACH THE LOWER TO
MIDDLE 30S FRIDAY...EFFECTIVELY ENDING THE FREEZING DRIZZLE THREAT.
ON FRIDAY NIGHT AND SATURDAY...FORECAST SOUNDINGS OVER THE EASTERN
THIRD OF THE FORECAST AREA ARE INDICATIVE OF ANOTHER EPISODE OF
FREEZING DRIZZLE LATE FRIDAY NIGHT INTO SATURDAY MORNING. ATTM...THE
THREAT FOR FREEZING DRIZZLE IS INDICATED ONLY IN THE NAM SOLN AS THE
GFS IS MORE AGGRESSIVE IN PUSHING THE ARCTIC AIRMASS EAST FRIDAY
NIGHT. GIVEN THE MODEL DIFFERENCES...WILL HOLD OFF ON MENTION OF
FREEZING DRIZZLE ATTM. ON SATURDAY...AN UPPER LEVEL DISTURBANCE
ACROSS THE NRN TIER OF STATES...WILL FORCE WARMER AIR INTO THE
FORECAST AREA...FOLLOWED BY A WEAK COOL FRONT SATURDAY NIGHT. LIGHT
WESTERLY WINDS SATURDAY WILL PUSH HIGHS INTO THE LOWER 40S.
SUNDAY THROUGH WEDNESDAY...AS THE UPPER LEVEL SYSTEM PUSHES EAST
MONDAY AND MONDAY NIGHT...THERE WILL BE AN INCREASED THREAT FOR LIGHT
PRECIPITATION IN THE FAR NORTHEAST...ALONG WITH A THREAT FOR
PRECIPITATION ACROSS THE CENTRAL AND NORTHERN ROCKIES...WHICH WILL
BE ENHANCED BY A STRONG UPPER LEVEL JET STREAK. BEYOND MONDAY
NIGHT...A DRY AND COLDER FORECAST IS EXPECTED ACROSS WESTERN AND
NORTH CENTRAL NEBRASKA AS ARCTIC AIR PUSHES SOUTH TUESDAY INTO
WEDNESDAY. ATTM...THE BEST THREAT FOR SNOW WILL BE OFF TO THE WEST
OF THE FORECAST AREA...HOWEVER...WE WILL NEED TO MONITOR NEXT
THURSDAY INTO NEXT WEEKEND AS THE LATEST ECMWF SOLN DIGS A DEEP
TROUGH INTO THE INTERMOUNTAIN WEST BY DAY 10.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1120 PM CST WED DEC 17 2014
A CLEARING LINE SHOULD BECOME ESTABLISHED ALONG OR NEAR HIGHWAY 83
THURSDAY.
LIFR/IFR CIGS AND VSBY CONTINUE OVERNIGHT AND IMPROVE TO VFR 18Z-
21Z ALONG AND WEST OF HIGHWAY 61. LIFR/IFR/MVFR CIGS CONTINUE ALONG
AND EAST OF HIGHWAY 83 THROUGH THURSDAY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...MASEK/JWS
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
853 PM PST WED DEC 17 2014
.SYNOPSIS...SCATTERED LIGHT RAIN SHOWERS AND MOUNTAIN SNOW SHOWERS
WILL DIMINISH OVERNIGHT AS A WEATHER SYSTEM SLOWLY MOVES ACROSS THE
DESERT SOUTHWEST. IMPROVING CONDITIONS ARE EXPECTED THURSDAY AND
FRIDAY. A FEW SHOWERS WILL BE POSSIBLE ACROSS THE GREAT BASIN OVER
THE WEEKEND FOLLOWED BY DRY AND WARMER WEATHER NEXT WEEK.
&&
.UPDATE...NOT A VERY WET STORM FOR OUR AREA, HOWEVER, THIS IS ONE OF
THE RARE MONTHS IN THE LAST FEW YEARS WITH ABOVE NORMAL
PRECIPITATION AND SO WE`LL TAKE WHATEVER WE CAN GET. MOST AREAS SAW
UNDER A QUARTER OF AN INCH OF PRECIPITATION WITH THIS EVENT AND THE
REALITY WAS ONLY A FEW HUNDREDTHS OF AN INCH AT MOST SPOTS. THE
EVENING SOUNDING SHOWED A SMALL MOIST LAYER BETWEEN 825 AND 725 MB
WHICH STILL SUPPORTS THE POTENTIAL FOR SOME PRECIPITATION TO REACH
THE GROUND THROUGH THE REST OF TONIGHT. OVERALL THE POP GRIDS LOOKED
OK, HOWEVER, THERE IS A SECOND PIECE OF ENERGY EXPECTED TO PUSH INTO
SOUTHEAST CALIFORNIA AND SOUTHERN NEVADA LATER TONIGHT THAT MAY SET
OFF SOME ADDITIONAL SHOWER ACTIVITY IN THE WESTERN CWFA. BOTH THE
WRF AND HRRR MODELS SUGGEST SOME SHOWER ACTIVITY WITH THIS FEATURE
ACROSS INYO, ESMERALDA AS WELL AS CENTRAL AND SOUTHERN NYE COUNTIES
AND POPS WERE ADJUSTED IN THESE AREAS FOR THE REST OF TONIGHT.
OTHERWISE THE FORECAST LOOKED IN GOOD SHAPE AND I WILL LEAVE IT BE.
&&
.AVIATION...FOR MCCARRAN...CEILINGS WILL HOVER AROUND 6 KFT BEFORE
PARTIALLY CLEARING AND LIFTING TO AROUND 10 KFT THURSDAY MORNING.
GENERALLY LIGHT WINDS WILL CONTINUE TONIGHT.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...CIGS OF 3K-6K FT AND MOUNTAIN OBSCURATIONS WILL
CONTINUE ACROSS MUCH OF THE REGION THROUGH THURSDAY MORNING
FOLLOWED BY PARTIAL CLEARING AS A WEAK WEATHER SYSTEM GRADUALLY
MOVES TO THE EAST.
&&
PREVIOUS DISCUSSION...
ISSUED 250 PM PST WED DEC 17 2014
.SHORT TERM...EXTENSIVE LOW TO MID LEVEL CLOUDS WERE APPARENT FROM
SATELLITE LOOPS AND SURFACE OBSERVATIONS ACROSS THE FORECAST AREA
AND THESE WILL BE SLOW TO CLEAR OUT TONIGHT THROUGH THURSDAY. RECENT
RADAR LOOPS SHOWED A SLIGHT UPWARD TREND IN SCATTERED SHOWERS ACROSS
SOUTHERN CLARK AND CENTRAL MOHAVE COUNTIES EARLY THIS AFTERNOON AND
THE HRRR MODEL INDICATES THIS WILL BE THE PRIMARY AREA FOR
PRECIPITATION THROUGH EARLY THIS EVENING. ANY ADDITIONAL SNOW
AMOUNTS IN THE MOUNTAINS OF SOUTHERN NEVADA AND NORTHWEST ARIZONA
ARE EXPECTED TO BE VERY LIGHT AND THE WINTER WEATHER ADVISORY HAS
BEEN CANCELLED. THE MEAN TROUGH OVER THE REGION WILL DIG A
LITTLE TONIGHT AS A SHORTWAVE WEST OF POINT CONCEPTION DIVES TOWARD
NORTHERN BAJA. AN ADDITIONAL BAND OF MOISTURE ASSOCIATED WITH THIS
SHORTWAVE WILL MOVE INTO THE SOUTHERN SIERRA OVERNIGHT AND WILL
PRODUCE A CHANCE OF VERY LIGHT SNOW OVER THE EASTERN SLOPES...SO
POPS WERE INCREASED ACCORDINGLY.
THE TROUGH AXIS WILL SHIFT EASTWARD THURSDAY WITH GRADUAL CLEARING
THURSDAY AFTERNOON THROUGH THURSDAY NIGHT. LITTLE CHANGE IN
TEMPERATURES CAN BE EXPECTED.
&&
.LONG TERM...FRIDAY THROUGH TUESDAY.
MEDIUM RANGE MODELS SIMILAR TO 24 HOURS AGO INDICATING MOST OF THE
ENERGY ASSOCIATED WITH NEXT SHORTWAVE TROUGH WILL AFFECT CENTRAL
NEVADA NORTHWARD FRIDAY NIGHT INTO SATURDAY. WITH THAT SAID, LEFT IN
SLIGHT CHANCE POPS FROM NORTHERN INYO COUNTY EASTWARD TO NORTHERN
LINCOLN COUNTY TO ACCOUNT FOR ANY POTENTIAL SOUTHWARD SHIFT.
SUNDAY THROUGH TUESDAY THE LONGWAVE PATTERN WILL BE DOMINATED BY A
STRONG RIDGE ALONG THE WEST COAST WITH A TROUGH EAST OF THE ROCKIES.
SOUTHERN GREAT BASIN/MOJAVE DESERT WILL LIE UNDER A DRY NORTHWEST
FLOW. SURFACE HIGH DEVELOPING OVER THE NORTHERN GREAT BASIN WILL
LEAD TO AN INCREASE IN NORTH BREEZES DOWN THE COLORADO RIVER VALLEY
SOUTH OF HOOVER DAM SUNDAY-TUESDAY.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS TODAY THROUGH THURSDAY ACCORDING
TO STANDARD OPERATING PROCEDURES.
&&
$$
UPDATE/AVIATION...STACHELSKI
SHORT TERM...ADAIR
LONG TERM...PIERCE
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
102 AM EST THU DEC 18 2014
.SYNOPSIS...
AN UPPER LEVEL STORM SYSTEM MOVING FROM THE GREAT LAKES TO NEW
ENGLAND WILL RESULT IN SCATTERED SNOW SHOWERS CONTINUING INTO
THURSDAY. FARTHER SOUTH A FEW SPRINKLES AND FLURRIES CAN BE
EXPECTED IN NORTHEAST PENNSYLVANIA. CLOUDS AND SEASONABLY COLD
TEMPERATURES WILL PERSIST FRIDAY INTO THE WEEKEND WITH SCATTERED
SNOW SHOWERS GRADUALLY DIMINISHING.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
740 PM UPDATE...
AREA OF PCPN HAS WEAKENED ACRS CWA THIS EVNG. UPR LVL S/WV IS NOW
ROTATING INTO WRN NY AND BRINGING STEEPENING MID-LVL LR TO THE
REGION. THIS ADDED LIFT COMBINED WITH LK MOISTURE WL SERVE TO
INCRS CVRG OF SNOW SHOWERS FOR PORTION OF OVRNGT IN 290-300 FLOW
ON EITHER SIDE OF MIDNIGHT.
EXPECT THAT OVRNGT SNOW ACCUMS ARND 1.5 INCHES IN FAVORED
LOCATIONS WITH HIGHEST AMNTS IN THE HIGHER TERRAIN OF UPR
SUSQUEHANNA REGION. ONLY MINOR CHGS MADE TO POPS WITH NO OTHER
CHGS NEEDED AT THIS TIME. EXPECT THAT NEPA WL STAY CLDY BUT VRY
LITTLE PCPN EXPECTED TO SNEAK INTO ZONES TONIGHT.
PREV DISCUSSION BLO...
A BAND OF STEADY LIGHT RAIN IS MOVING EAST ACROSS CENTRAL NY THIS
AFTERNOON WITH A CHANGE-OVER TO LIGHT SNOW ALREADY OCCURRING OVER
THE HIGHER ELEVATIONS AS OF 3 PM. THIS BAND WILL LIFT EAST-
NORTHEAST TOWARD THE CATSKILLS AND MOHAWK VALLEY THROUGH LATE THIS
AFTERNOON WITH LOWER ELEVATIONS GRADUALLY MIXING WITH OR CHANGING
TO LIGHT SNOW AS COLDER AIR FILTERS IN FROM THE WEST. MEANWHILE...
MAINLY DRY WEATHER CAN BE EXPECTED TO CONTINUE IN THE WILKES-BARRE
AND SCRANTON AREAS AND POINTS SOUTH WITH PRECIPITATION REMAINING
TO THE NORTH.
PRECIPITATION SHOULD BECOME SPOTTIER AND LIGHTER EARLY THIS
EVENING IN MANY AREAS... THEN UPPER LEVEL LOW PRESSURE CURRENTLY
OVER WESTERN MICHIGAN WILL TRACK RAPIDLY EAST ACROSS THE AREA
LATER TONIGHT. THIS COULD RESULT IN A PERIOD OF ENHANCED SNOW
SHOWERS AGAIN LATE TONIGHT INTO EARLY THURSDAY MORNING. A BIT OF
LAKE ENHANCEMENT COULD ALSO OCCUR SOUTHEAST OF LAKE ONTARIO LATE
TONIGHT AS 850 MB TEMPERATURES FALL TO AROUND -8 C. LATEST HIGH
RESOLUTION NAM AND HRRR BOTH SUPPORT THE IDEA THAT SNOW SHOWERS
MAY INCREASE IN COVERAGE LATE TONIGHT WITH THE PASSAGE OF THIS
SYSTEM. BASED ON THIS HAVE UPPED POPS INTO THE LIKELY CATEGORY
LATER TONIGHT AND HAVE UP TO AN INCH OF SNOW POSSIBLE ESPECIALLY
AT HIGHER ELEVATIONS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
UPPER LEVEL AND SURFACE LOW PRESSURE WILL TRACK SLOWLY EAST ACROSS
THE SOUTHERN CANADIAN MARITIMES THURSDAY THROUGH FRIDAY. FLOW
ACROSS OUR AREA IN THE WAKE OF THIS SYSTEM WILL BE NORTHWESTERLY WITH
PLENTY OF LOW-LEVEL MOISTURE AND 850 MB TEMPERATURES HOLDING
AROUND -8 TO -10 C... WHICH WILL BE JUST COLD ENOUGH FOR A MINOR
LAKE RESPONSE IN THE NORTHWEST FLOW. HOWEVER MOISTURE WILL BECOME
INCREASINGLY SHALLOW WITH CONSIDERABLE DRYING IN THE -10 TO -20
DEGREE SNOW GROWTH ZONE BY THURSDAY AFTERNOON. BASED ON THIS
EXPECT JUST SCATTERED LIGHT SNOW SHOWERS THURSDAY AFTERNOON INTO
FRIDAY WITH ONLY MINIMAL ACCUMULATIONS. SOME FREEZING DRIZZLE
MIGHT EVEN OCCUR THURSDAY NIGHT ALTHOUGH AT THIS POINT I THINK
THAT IS A LOW PROBABILITY SCENARIO AND I HAVE NOT INCLUDED ZL IN
THE GRIDDED FORECAST. AT THIS POINT IT APPEARS THAT CLOUDS WILL
PERSIST THROUGH FRIDAY. WITH PLENTY OF CLOUDS WE ARE NOT EXPECTING
MUCH DIURNAL VARIATION IN TEMPERATURES THROUGH FRIDAY WITH HIGHS
MAINLY 30 TO 35 AND LOWS 20 TO 25 IN MOST PLACES.
BEST CHANCE TO SEE ANY SUNSHINE MIGHT BE EARLY SATURDAY BEFORE
CLOUDS AHEAD OF THE NEXT SYSTEM STREAM NORTHEAST ACROSS THE AREA
DURING THE AFTERNOON. SATURDAY SHOULD BE DRY WITH TEMPERATURES
AGAIN MAINLY IN THE 30S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
1 PM UPDATE..
FOLLOWED WPC GUIDANCE FOR THE MOST PART. SAT NGT AND SUN SOME
LIGHT SNOW WITH AN INVERTED TROF FROM A COASTAL STORM WELL OUT TO
SEA. SNOW ACCUMULATIONS WILL BE MOSTLY 2 INCHES OR LESS.
DRY SUN NGT AND MON WITH A MILD SFC HIGH. MON NGT AND TUE MODELS
NOW TRYING TO BRING A WEAK COASTAL STORM NE INTO THE AREA WITH
MIXED PRECIP. ADDED SOME LOW CHC POPS.
WED A STRONG OCCLUDED FRONT LIFTS NE AHEAD OF A LARGE BOMBING
STACKED LOW IN THE MIDWEST. WARM AIR SO PRECIP MOSTLY RAIN. THIS
WILL NEED TO BE WATCHED FIRST FOR RAIN AMOUNTS AND POSSIBLY
FLOODING AND SECOND FOR STRONG GUSTY WINDS.
ON THE TAIL END OF THE STEADY RAIN IT WILL CHANGE OVER TO SNOW WED
NGT AND STAY COLD THE REST OF THE WEEK WITH WRAP AROUND SNOW.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
06Z UPDATE...
UPPER WAVE IS NOW MOVING THROUGH DURING THE PREDAWN HOURS...WHICH
ALONG WITH LAKE MOISTURE WILL CAUSE A QUICK BURST OF -SHSN FOR THE
TERMINALS INCLUDING TEMPO IFR VIS FOR SEVERAL. BEYOND 10Z...WAVE
WILL BE ALREADY ZIPPING AWAY...WITH WNW FLOW AND STUBBORN MVFR DECK
IN ITS WAKE THROUGH THE REMAINDER OF TAF PERIOD /EXCEPT KAVP
PROBABLY LOSING IT TOWARDS 00Z/. IN MOST CASES...FUEL ALT MVFR
CIG. AS FOR -SHSN...WITH WAVE GONE IT BECOMES SIMPLY A QUESTION OF
LAKE EFFECT PLACEMENT...AND KSYR WILL BE MOST FAVORED. ALSO...KITH
FOR A TIME LATE AFTERNOON-EARLY EVENING WILL HAVE FAVORABLE WIND
FLOW DOWN CAYUGA LAKE TO GENERATE -SHSN WITH IFR VIS. OTHER
TERMINALS EXCEPT KAVP COULD GET A FLURRY PRETTY MUCH ANYTIME
TODAY...BUT WITH CLOUD LAYER SHALLOW ENOUGH TO PREVENT THE
FLUFFIER DENDRITE FLAKES...AND THUS PROBABLY NOT REDUCING VIS VERY
MUCH.
OUTLOOK...
FRI...MVFR CIG AND PERHAPS LINGERING -SN EARLY ESPECIALLY NY
TERMINALS. CIGS GRADUALLY LIFTING TO VFR.
FRI NGT TO SAT...VFR.
SAT NGT THROUGH MON...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE/PVF
SHORT TERM...MSE
LONG TERM...TAC
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
314 AM CST THU DEC 18 2014
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 314 AM CST THU DEC 18 2014
MAIN ISSUE TODAY WILL BE CLOUDS MOVING INTO THE WEST AND IF WE GET
ANY SNOW OF MENTION OR JUST FLURRIES.
A WEAK UPPER SHORTWAVE TROUGH IS SEEN ON WV LOOP ROTATING OVER THE
MT/ND BORDER...AND THAT FEATURE WILL MOVE INTO THE EASTERN DAKOTAS
TODAY. THIS WILL HELP BRING SOME FAIRLY WEAK SYNOPTIC LIFT INTO THE
REGION. THE SFC HIGH WILL MOVE OFF TO THE EAST...ALLOWING SOUTH
WINDS AND MORE MOISTURE TO MOVE BACK INTO THE AREA. THERE HAS BEEN
A DECENT BAND OF SNOW OVER CENTRAL ND...WHICH MATCHES PRETTY WELL
WHERE THE RAP HAS SOME Q VECTOR CONVERGENCE COINCIDING WITH
FRONTOGENESIS. THE RAP HAS THIS FEATURE WEAKENING SIGNIFICANTLY AS
IT MOVES EAST INTO OUR CWA LATER THIS MORNING...SO THINK A WELL
DEFINED BAND OF SNOW IS NOT TOO LIKELY. HOWEVER...SOME VERY LIGHT
SNOW IS NOT OUT OF THE QUESTION. INCLUDED SOME LOW POPS IN THE FAR
WEST WITH SOME FLURRIES GRADUALLY MOVING TOWARDS THE RED RIVER AS
CLOUDS CONTINUE TO INCREASE THROUGHOUT THE DAY IN THE WESTERN
COUNTIES. TEMPS TODAY SHOULD BE A BIT WARMER EVEN WITH CLOUDS AS
TEMPS UNDER THE CLOUDS ARE ALREADY CLOSE TO 20 DEGREES OUT WEST.
WILL CONTINUE TO KEEP HIGHS IN THE UPPER TEENS TO 20S.
TONIGHT...THE WEAK UPPER TROUGH CONTINUES OVER THE NORTHERN
PLAINS...WITH WARM AIR ADVECTION CONTINUING THROUGHOUT THE NIGHT.
CLOUDS WILL CONTINUE TO MOVE INTO THE AREA AND THAT ALONG WITH THE
SOUTH WINDS WILL PREVENT TEMPS FROM BOTTOMING OUT TONIGHT. TEMPS
SHOULD STAY MAINLY IN THE TEENS. THE WARM AIR ADVECTION WILL
CONTINUE INTO FRIDAY...ALLOWING TEMPS TO GET WELL INTO THE 20S TO
NEAR 30 IN THE SOUTH. MODELS CONTINUE TO SHOW SOME VERY LIGHT
PRECIP AS ISENTROPIC LIFT CONTINUES AND CONDENSATION PRESSURE
DEFICITS BECOME MORE FAVORABLE...MAINLY IN THE NORTHEASTERN
COUNTIES. WILL CONTINUE TO KEEP 20 POPS GOING FOR LIGHT SNOW...BUT
THINK THAT ANY ACCUMULATION WILL BE VERY LIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 314 AM CST THU DEC 18 2014
FRIDAY NIGHT THROUGH SATURDAY NIGHT...THE WEAK UPPER TROUGH
LINGERS OVER NORTHERN MN...AND THE NEXT SHORTWAVE TROUGH BEGINS TO
APPROACH FROM THE WEST. SOUTH WINDS WILL CONTINUE AND MOISTURE
SHOULD BE INCREASING. THERE CONTINUE TO BE SOME SIGNS OF PRECIP
MOVING IN WITH THAT SECOND SHORTWAVE LATE SATURDAY INTO SATURDAY
NIGHT. THERE IS A LOT OF VARIATION FROM THE NAM SHOWING UP TO A
TENTH OF AN INCH TO THE ECMWF HAVING HARDLY ANYTHING...SO KEPT
POPS LOW FOR NOW. THE SREF SHOWS SOME FZRA PROBABILITIES FOR
SATURDAY NIGHT...BUT THE TOP DOWN METHOD GIVES MOSTLY SNOW IN THE
NORTH WHERE POPS ARE LOCATED WITH THE WARM LAYER ALOFT STAYING
MOSTLY IN OUR SOUTH WHERE CURRENTLY WE ARE GOING DRY. WILL KEEP A
CLOSE EYE ON THE SITUATION. TEMPS WILL BE ABOVE AVERAGE WITH HIGHS
PUSHING 30 DEGREES AND LOWS STAYING IN THE TEENS TO EVEN LOW 20S.
FOR SUNDAY THROUGH WEDNESDAY...UPPER PATTERN SHIFTS A BIT BECOMING
MORE OF A NW FLOW REGIME WITH THE RIDGE AXIS OVER THE INTERMOUNTAIN
WEST. HOWEVER...THE MAIN JET ENERGY IS EXPECTED TO REMAIN WEST AND
SOUTH OF THE AREA. A FEW WAVES PUSHING ACROSS THE AREA WILL BRING
CHANCES FOR LIGHT PCPN...WHILE TEMPERATURES CONTINUE TO REMAIN NEAR
OR SLIGHTLY ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1130 PM CST WED DEC 17 2014
CLOUDS WILL CONTINUE APPROACHING THE REGION FROM THE WEST...BUT
WILL TAKE THEIR TIME GETTING HERE. THE MVFR CIGS WILL LIKELY MOVE
INTO KDVL BY MID-LATE AFTERNOON...VALLEY SITES CLOSER TO MIDNIGHT.
LIGHT WINDS WILL GRADUALLY BECOME SOUTHERLY...BUT REMAIN AOB 10
KNOTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...JR
LONG TERM...JR/HOPKINS
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
216 AM CST THU DEC 18 2014
.UPDATE...
ISSUED AT 215 AM CST THU DEC 18 2014
QUICK UPDATE AS A NARROW BAND OF MODERATE TO HEAVY SNOW PER LATEST
RADAR...AND CONFIRMATION FROM LOCAL LAW ENFORCEMENT ACROSS WEST
CENTRAL NORTH DAKOTA. THE GFS 1.5 PVU 850-700MB AXIS ATOP AN AREA
OF 850MB FRONTOGENESIS IS RESULTING IN A NARROW BAND OF HEAVY
SNOWFALL. TIGHT CIRCULATION CAN BE SEEN ON THE 0.5 DEGREE RADAR
SLICE. THE BAND OF SNOW BEGINS FROM HIGHWAY 8...JUST WEST OF
HALLIDAY WHERE LAW ENFORCEMENT REPORTED VISIBILITY OF AROUND
FIFTEEN 15 FEET WITH ABOUT A HALF INCH OF SNOW. WEBCAMS AT
COLEHARBOR AND WHITE SHIELD CONFIRM BRIEF BUT INTENSE SNOW. HAVE
UPDATED THE GRIDDED FORECAST AND FOLLOWED THIS AXIS THROUGH THE
MORNING AS IT SLIDES NORTH. THE BAND EXTENDS SOUTHEAST INTO
GARRISON...WILTON...REGAN AND WING. A NOWCAST WAS SENT EARLIER
REFLECT CURRENT CONDITIONS. UPDATES TO THE TEXT PRODUCTS
FORTHCOMING.
UPDATE ISSUED AT 1212 AM CST THU DEC 18 2014
LATEST WATER VAPOR IMAGERY LOOP PLACES AN UPPER LOW CIRCULATING JUST
SOUTH OF WILLISTON WITH A SHORTWAVE MOVING INTO THE BASE OF THE
TROUGH...LOCATED ACROSS SOUTHEAST MONTANA. THIS SHORTWAVE IS
FORECAST TO PROPAGATE SLOWLY EAST OVERNIGHT/THURSDAY...BEING LOCATED
BETWEEN DICKINSON AND BISMARCK BY 12Z...AND BETWEEN BISMARCK AND
JAMESTOWN BY 18Z THURSDAY. THE LATEST RAP13 BUFKIT SOUNDINGS FOR
KDIK/KBIS/KJMS INDICATE ENOUGH OMEGA/LIFT IN THE LOW LEVEL SATURATED
LAYER WITH RESPECT TO ICE. AS THE FROST POINT EXCEEDS THE
TEMPERATURE...SNOW PRODUCTION WILL RESULT IN THE SUPERSATURATED
ENVIRONMENT FOR A MENTION OF ISOLATED TO SCATTERED SNOW
SHOWERS/MEASURABLE AMOUNTS OVERNIGHT INTO THURSDAY AFTERNOON AS IT
SLOWLY MOVES EAST. HAVE UPDATED THE GRIDS FOR THIS FEATURE AND WILL
MONITOR AS IT EVOLVES THROUGH THE EARLY MORNING. THINKING IS ONE TO
TWO TENTHS OF AN INCH OF SNOW POSSIBLE ACROSS PORTIONS SOUTHERN
NORTH DAKOTA. SCATTERED FLURRIES STILL A GOOD BET WITH THE ACTUAL
UPPER LOW IN THE NORTHWEST AND NORTH CENTRAL OVERNIGHT AND WILL
CONTINUE WITH THIS IDEA.
UPDATE ISSUED AT 949 PM CST WED DEC 17 2014
MAIN ISSUE LATE THIS EVENING WILL BE LIGHT SNOW/FLURRY CHANCES.
TEMPERATURES WILL BE A HASSLE AGAIN ALONG THE BORDER BETWEEN THE
LOW CLOUDS AND CLEAR SKIES OVER CENTRAL ND...BUT TREND SEEMS
REASONABLE SO NO BIG CHANGES HERE.
LATEST 00 UTC NAM AND 02 UTC RAP SHOW A COUPLE SHORTWAVE IMPULSES
ROTATING AROUND AN UPPER LOW OVER EASTERN MONTANA. THE LEAD WAVE
IS AIDING IN THE DEVELOPMENT OF A SMALL BAND OF SNOW SHOWERS
LIFTING NORTHWARD THROUGH SOUTHWEST INTO CENTRAL NORTH DAKOTA.
GROUND REPORTS ARE INDICATING A BRIEF PERIOD OF SNOW SHOWERS WITH
NO SIGNIFICANT ACCUMULATIONS. WITH THE SMALL BAND LIFTING QUICKLY
NORTH...OPTED TO KEEP THIS AS A CONTINUED MENTION OF FLURRIES AS
GETTING A HUNDREDTH OF AN INCH IS NOT LIKELY.
LATER TONIGHT AND INTO THURSDAY MORNING A STRONGER SHORTWAVE MOVES
WEST ALONG THE NORTH DAKOTA/SOUTH DAKOTA BORDER. ALTHOUGH RAP/NAM
QPF IS CURRENTLY NIL...THE RAP/HRRR ARE SHOWING SOME LIGHT RADAR
REFLECTIVITIES DEVELOPING OVER SOUTHWEST NORTH DAKOTA IN THE 07-12
UTC TIMEFRAME. THINKING AS WE GO THROUGH A FEW MORE ITERATIONS OF
THE RAP/HRRR...THIS MAY CONTINUE TO PROGRESS INTO THE SOUTH
CENTRAL DURING THE MORNING HOURS...AND POSSIBLY INCREASE GIVEN THE
STRENGTH OF THE SHORTWAVE. WITH A MOIST BOUNDARY LAYER AND
INCREASING SEEDER-FEEDER MECHANISM WITH INCREASING MID LEVEL
CLOUDS...HAVE EXTENDED FLURRIES THROUGH THURSDAY MORNING ACROSS
WESTERN AND CENTRAL NORTH DAKOTA. THINK MID SHIFT WILL HAVE THE
TIME TO RE-EVALUATE AND ADD A MENTION OF LIGHT SNOW FOR THE
MORNING HOURS IF NEEDED. ACCUMULATIONS WILL REMAIN LIGHT BUT THIS
SECOND WAVE LOOKS STRONG ENOUGH TO GIVE SOME OF US A LITTLE MORE
THAN JUST FLURRIES.
UPDATE ISSUED AT 551 PM CST WED DEC 17 2014
LOW STRATUS REMAINS ACROSS MUCH OF WESTERN AND CENTRAL NORTH
DAKOTA...AND WILL ONCE AGAIN BE A CONCERN FOR OVERNIGHT LOW
TEMPERATURES. DO EXPECT THE STRATUS TO BEGIN TO PROGRESS EASTWARD
LATER THIS EVENING AND OVERNIGHT...COVERING MOST IF NOT ALL OF THE
FORECAST AREA BY THURSDAY MORNING. SHORTWAVE LOCATED OVER EASTERN
MONTANA WILL PROVIDE ENOUGH LIFT FOR SOME LIGHT SNOW SHOWERS
MAINLY OVER THE SOUTHWEST. HOWEVER...WHEREVER WE HAVE THE STRATUS
WE CAN EXPECT A FEW FLURRIES. THIS IS CURRENTLY HANDLED WELL BY
PREVIOUS FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 352 PM CST WED DEC 17 2014
CURRENT SURFACE ANALYSIS PLACES HIGH OVER THE MIDWEST WITH TROUGH
MOVING TOWARDS THE SOUTHERN PLAINS. UPPER LEVEL ANALYSIS PLACES
RIDGE WORKING TOWARDS THE MIDWEST WITH COMPACT LOW LIFTING THROUGH
EASTERN MONTANA. BROAD LOW CLOUD COVER REMAINS OVER WESTERN NORTH
DAKOTA...THOUGH SOME HIGHER CLOUDS ARE ALSO MOVING THROUGH WITH
APPROACHING UPPER LOW.
FOR TONIGHT...CLOUD COVER OVER THE WEST WILL SPREAD TOWARDS THE
EAST THROUGH THE NIGHT. SOME LIGHT SNOW IS POSSIBLE WITH
APPROACHING UPPER LOW...MAINLY OVER THE SOUTHWEST...BUT WITH
LIMITED MOISTURE AVAILABLE ANY ACCUMULATIONS WILL BE QUITE LIGHT.
ELSEWHERE...FLURRIES REMAIN POSSIBLE.
ON THURSDAY...UPPER LOW CONTINUES TO SLOWLY WORK ITS WAY TO THE
EAST WHILE MILDER AIRMASS SLOWLY STARTS TO WORK ITS WAY INTO THE
AREA...BRINGING TEMPERATURES CLOSER TO AVERAGE. MODELS CONTINUE TO
KEEP MOISTURE IN PLACE OVER THE REGION KEEPING CLOUDY SKIES OVER
MOST LOCATIONS...WITH SOME CLEARING DEVELOPING OVER THE FAR WEST
IN THE AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 352 PM CST WED DEC 17 2014
QUIET THROUGH SATURDAY...ACTIVE END TO THE WEEKEND AND EARLY
HOLIDAY WEEK.
A WEAK SHORTWAVE TROUGH IS PROGGED TO SWING ACROSS SOUTHERN CANADA
SATURDAY/SUNDAY. THIS COULD SPARK SOME LIGHT SNOW SHOWERS ACROSS
NORTHERN NORTH DAKOTA. HOWEVER...IF ANY PRECIPITATION DOES DEVELOP
ONLY VERY LIGHT AMOUNTS SEEM POSSIBLE WITH THIS WAVE AS IT SHOULD BE
DISCONNECTED FROM THE MAIN PACIFIC MOISTURE FLOW THAT WILL ARRIVE
LATER SUNDAY INTO MONDAY.
SPEAKING OF SUNDAY INTO MONDAY...BROAD NORTHWEST FLOW AND A
LONGWAVE TROUGH IS EXPECTED TO DEVELOP ACROSS THE NORTHERN
PLAINS. THIS WILL LEAD TO A MUCH MORE ACTIVE WEATHER PERIOD. AT
THIS TIME IT APPEARS THE MOST SIGNIFICANT IMPACTS WITH THIS SYSTEM
WILL REMAIN JUST SOUTH AND EAST. HOWEVER...THE LATEST MODELS (12
UTC ECMWF/GFS) VARY GREATLY IN THE EVOLUTION OF THIS WAVE AND
PRECIPITATION PLACEMENT. THEREFORE...CLOSE ATTENTION WILL BE GIVEN
TO FOLLOWING MODEL RUNS AND THE EVOLUTION OF THIS SIGNIFICANT WAVE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1212 AM CST THU DEC 18 2014
IFR STRATUS CONTINUES AT KDIK WITH MVFR STRATUS AT KDIK. LOW STRATUS
IS EXPECTED TO MOVE INTO CENTRAL NORTH DAKOTA (KBIS-KMOT) 07-10 UTC
AND INTO KJMS 13-16 UTC. THE LOW STRATUS IS EXPECTED TO LINGER AT
ALL AERODROMES THROUGH THE FORECAST PERIOD. COULD SEE SOME LIFTING
AT KDIK LATE IN THE PERIOD BUT FOR NOW WILL KEEP THE LOW CLOUDS AT
KDIK THROUGH 06 UTC.
A COUPLE SHORTWAVES ROTATING AROUND AN UPPER LOW...WHICH TRACKS EAST
ACROSS THE FORECAST AREA THROUGH THURSDAY WILL PROVIDE PERIOD OF
LIGHT SNOW. THE FIRST IS EXPECTED TO BRING SOME POSSIBLE LIGHT SNOW
TO KISN AND KMOT LATE TONIGHT. THE SECOND WAVE WILL PROVIDE A CHANCE
OF LIGHT SNOW ACROSS THE SOUTHERN TAF SITES...KDIK AROUND 10-16
UTC...KBIS AROUND 14-20 UTC AND KJMS AROUND 18-24 UTC. DID ADD A
TEMPO AT KDIK AND KBIS FOR SOME LOWER CEILINGS/VSBYS IN SNOW
SHOWERS. WILL HOLD OFF ON LOWER CIGS/VSBYS FOR KJMS AT THIS TIME AS
IT`S PRETTY FAR OUT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...JJS
LONG TERM...AJ
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1212 AM CST THU DEC 18 2014
.UPDATE...
ISSUED AT 1212 AM CST THU DEC 18 2014
LATEST WATER VAPOR IMAGERY LOOP PLACES AN UPPER LOW CIRCULATING JUST
SOUTH OF WILLISTON WITH A SHORTWAVE MOVING INTO THE BASE OF THE
TROUGH...LOCATED ACROSS SOUTHEAST MONTANA. THIS SHORTWAVE IS
FORECAST TO PROPAGATE SLOWLY EAST OVERNIGHT/THURSDAY...BEING LOCATED
BETWEEN DICKINSON AND BISMARCK BY 12Z...AND BETWEEN BISMARCK AND
JAMESTOWN BY 18Z THURSDAY. THE LATEST RAP13 BUFKIT SOUNDINGS FOR
KDIK/KBIS/KJMS INDICATE ENOUGH OMEGA/LIFT IN THE LOW LEVEL SATURATED
LAYER WITH RESPECT TO ICE. AS THE FROST POINT EXCEEDS THE
TEMPERATURE...SNOW PRODUCTION WILL RESULT IN THE SUPERSATURATED
ENVIRONMENT FOR A MENTION OF ISOLATED TO SCATTERED SNOW
SHOWERS/MEASURABLE AMOUNTS OVERNIGHT INTO THURSDAY AFTERNOON AS IT
SLOWLY MOVES EAST. HAVE UPDATED THE GRIDS FOR THIS FEATURE AND WILL
MONITOR AS IT EVOLVES THROUGH THE EARLY MORNING. THINKING IS ONE TO
TWO TENTHS OF AN INCH OF SNOW POSSIBLE ACROSS PORTIONS SOUTHERN
NORTH DAKOTA. SCATTERED FLURRIES STILL A GOOD BET WITH THE ACTUAL
UPPER LOW IN THE NORTHWEST AND NORTH CENTRAL OVERNIGHT AND WILL
CONTINUE WITH THIS IDEA.
UPDATE ISSUED AT 949 PM CST WED DEC 17 2014
MAIN ISSUE LATE THIS EVENING WILL BE LIGHT SNOW/FLURRY CHANCES.
TEMPERATURES WILL BE A HASSLE AGAIN ALONG THE BORDER BETWEEN THE
LOW CLOUDS AND CLEAR SKIES OVER CENTRAL ND...BUT TREND SEEMS
REASONABLE SO NO BIG CHANGES HERE.
LATEST 00 UTC NAM AND 02 UTC RAP SHOW A COUPLE SHORTWAVE IMPULSES
ROTATING AROUND AN UPPER LOW OVER EASTERN MONTANA. THE LEAD WAVE
IS AIDING IN THE DEVELOPMENT OF A SMALL BAND OF SNOW SHOWERS
LIFTING NORTHWARD THROUGH SOUTHWEST INTO CENTRAL NORTH DAKOTA.
GROUND REPORTS ARE INDICATING A BRIEF PERIOD OF SNOW SHOWERS WITH
NO SIGNIFICANT ACCUMULATIONS. WITH THE SMALL BAND LIFTING QUICKLY
NORTH...OPTED TO KEEP THIS AS A CONTINUED MENTION OF FLURRIES AS
GETTING A HUNDREDTH OF AN INCH IS NOT LIKELY.
LATER TONIGHT AND INTO THURSDAY MORNING A STRONGER SHORTWAVE MOVES
WEST ALONG THE NORTH DAKOTA/SOUTH DAKOTA BORDER. ALTHOUGH RAP/NAM
QPF IS CURRENTLY NIL...THE RAP/HRRR ARE SHOWING SOME LIGHT RADAR
REFLECTIVITIES DEVELOPING OVER SOUTHWEST NORTH DAKOTA IN THE 07-12
UTC TIMEFRAME. THINKING AS WE GO THROUGH A FEW MORE ITERATIONS OF
THE RAP/HRRR...THIS MAY CONTINUE TO PROGRESS INTO THE SOUTH
CENTRAL DURING THE MORNING HOURS...AND POSSIBLY INCREASE GIVEN THE
STRENGTH OF THE SHORTWAVE. WITH A MOIST BOUNDARY LAYER AND
INCREASING SEEDER-FEEDER MECHANISM WITH INCREASING MID LEVEL
CLOUDS...HAVE EXTENDED FLURRIES THROUGH THURSDAY MORNING ACROSS
WESTERN AND CENTRAL NORTH DAKOTA. THINK MID SHIFT WILL HAVE THE
TIME TO RE-EVALUATE AND ADD A MENTION OF LIGHT SNOW FOR THE
MORNING HOURS IF NEEDED. ACCUMULATIONS WILL REMAIN LIGHT BUT THIS
SECOND WAVE LOOKS STRONG ENOUGH TO GIVE SOME OF US A LITTLE MORE
THAN JUST FLURRIES.
UPDATE ISSUED AT 551 PM CST WED DEC 17 2014
LOW STRATUS REMAINS ACROSS MUCH OF WESTERN AND CENTRAL NORTH
DAKOTA...AND WILL ONCE AGAIN BE A CONCERN FOR OVERNIGHT LOW
TEMPERATURES. DO EXPECT THE STRATUS TO BEGIN TO PROGRESS EASTWARD
LATER THIS EVENING AND OVERNIGHT...COVERING MOST IF NOT ALL OF THE
FORECAST AREA BY THURSDAY MORNING. SHORTWAVE LOCATED OVER EASTERN
MONTANA WILL PROVIDE ENOUGH LIFT FOR SOME LIGHT SNOW SHOWERS
MAINLY OVER THE SOUTHWEST. HOWEVER...WHEREVER WE HAVE THE STRATUS
WE CAN EXPECT A FEW FLURRIES. THIS IS CURRENTLY HANDLED WELL BY
PREVIOUS FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 352 PM CST WED DEC 17 2014
CURRENT SURFACE ANALYSIS PLACES HIGH OVER THE MIDWEST WITH TROUGH
MOVING TOWARDS THE SOUTHERN PLAINS. UPPER LEVEL ANALYSIS PLACES
RIDGE WORKING TOWARDS THE MIDWEST WITH COMPACT LOW LIFTING THROUGH
EASTERN MONTANA. BROAD LOW CLOUD COVER REMAINS OVER WESTERN NORTH
DAKOTA...THOUGH SOME HIGHER CLOUDS ARE ALSO MOVING THROUGH WITH
APPROACHING UPPER LOW.
FOR TONIGHT...CLOUD COVER OVER THE WEST WILL SPREAD TOWARDS THE
EAST THROUGH THE NIGHT. SOME LIGHT SNOW IS POSSIBLE WITH
APPROACHING UPPER LOW...MAINLY OVER THE SOUTHWEST...BUT WITH
LIMITED MOISTURE AVAILABLE ANY ACCUMULATIONS WILL BE QUITE LIGHT.
ELSEWHERE...FLURRIES REMAIN POSSIBLE.
ON THURSDAY...UPPER LOW CONTINUES TO SLOWLY WORK ITS WAY TO THE
EAST WHILE MILDER AIRMASS SLOWLY STARTS TO WORK ITS WAY INTO THE
AREA...BRINGING TEMPERATURES CLOSER TO AVERAGE. MODELS CONTINUE TO
KEEP MOISTURE IN PLACE OVER THE REGION KEEPING CLOUDY SKIES OVER
MOST LOCATIONS...WITH SOME CLEARING DEVELOPING OVER THE FAR WEST
IN THE AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 352 PM CST WED DEC 17 2014
QUIET THROUGH SATURDAY...ACTIVE END TO THE WEEKEND AND EARLY
HOLIDAY WEEK.
A WEAK SHORTWAVE TROUGH IS PROGGED TO SWING ACROSS SOUTHERN CANADA
SATURDAY/SUNDAY. THIS COULD SPARK SOME LIGHT SNOW SHOWERS ACROSS
NORTHERN NORTH DAKOTA. HOWEVER...IF ANY PRECIPITATION DOES DEVELOP
ONLY VERY LIGHT AMOUNTS SEEM POSSIBLE WITH THIS WAVE AS IT SHOULD BE
DISCONNECTED FROM THE MAIN PACIFIC MOISTURE FLOW THAT WILL ARRIVE
LATER SUNDAY INTO MONDAY.
SPEAKING OF SUNDAY INTO MONDAY...BROAD NORTHWEST FLOW AND A
LONGWAVE TROUGH IS EXPECTED TO DEVELOP ACROSS THE NORTHERN
PLAINS. THIS WILL LEAD TO A MUCH MORE ACTIVE WEATHER PERIOD. AT
THIS TIME IT APPEARS THE MOST SIGNIFICANT IMPACTS WITH THIS SYSTEM
WILL REMAIN JUST SOUTH AND EAST. HOWEVER...THE LATEST MODELS (12
UTC ECMWF/GFS) VARY GREATLY IN THE EVOLUTION OF THIS WAVE AND
PRECIPITATION PLACEMENT. THEREFORE...CLOSE ATTENTION WILL BE GIVEN
TO FOLLOWING MODEL RUNS AND THE EVOLUTION OF THIS SIGNIFICANT WAVE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1212 AM CST THU DEC 18 2014
IFR STRATUS CONTINUES AT KDIK WITH MVFR STRATUS AT KDIK. LOW STRATUS
IS EXPECTED TO MOVE INTO CENTRAL NORTH DAKOTA (KBIS-KMOT) 07-10 UTC
AND INTO KJMS 13-16 UTC. THE LOW STRATUS IS EXPECTED TO LINGER AT
ALL AERODROMES THROUGH THE FORECAST PERIOD. COULD SEE SOME LIFTING
AT KDIK LATE IN THE PERIOD BUT FOR NOW WILL KEEP THE LOW CLOUDS AT
KDIK THROUGH 06 UTC.
A COUPLE SHORTWAVES ROTATING AROUND AN UPPER LOW...WHICH TRACKS EAST
ACROSS THE FORECAST AREA THROUGH THURSDAY WILL PROVIDE PERIOD OF
LIGHT SNOW. THE FIRST IS EXPECTED TO BRING SOME POSSIBLE LIGHT SNOW
TO KISN AND KMOT LATE TONIGHT. THE SECOND WAVE WILL PROVIDE A CHANCE
OF LIGHT SNOW ACROSS THE SOUTHERN TAF SITES...KDIK AROUND 10-16
UTC...KBIS AROUND 14-20 UTC AND KJMS AROUND 18-24 UTC. DID ADD A
TEMPO AT KDIK AND KBIS FOR SOME LOWER CEILINGS/VSBYS IN SNOW
SHOWERS. WILL HOLD OFF ON LOWER CIGS/VSBYS FOR KJMS AT THIS TIME AS
IT`S PRETTY FAR OUT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...JJS
LONG TERM...AJ
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1259 AM EST THU DEC 18 2014
.SYNOPSIS...
WEAK HIGH PRESSURE WILL NOSE INTO THE REGION TONIGHT. HOWEVER
ABUNDANT LOW LEVEL MOISTURE WILL RESULT IN A CONTINUATION OF MAINLY
CLOUDY SKIES. A WEAK UPPER LEVEL DISTURBANCE COULD LEAD TO A FEW
FLURRIES THURSDAY AFTERNOON INTO THURSDAY NIGHT. HIGH PRESSURE WILL
BUILD BACK IN OFFERING DRY CONDITIONS AND NEAR SEASONABLE
TEMPERATURES FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AN ELONGATED AREA OF HIGH PRESSURE IS CURRENTLY CENTERED WEST OF
THE OHIO VALLEY. THIS HIGH WILL NUDGE INTO THE AREA BY
MORNING...WITH COOL WNW FLOW ON ITS NORTH SIDE ALLOWING FOR A
RELATIVE MIN IN SURFACE/925MB TEMPS THAT WILL STRETCH FROM CENTRAL
OHIO TO MINNESOTA. TEMPERATURES HAVE BEEN COOLING OFF A LITTLE
FASTER THAN THE PREVIOUS FORECAST INDICATED...SO A SLIGHT DOWNWARD
ADJUSTMENT WAS MADE TO THE MIN TEMPERATURE GRID.
AS THE PRESSURE GRADIENT WEAKENS...WINDS WILL BECOME LIGHTER AS
THE OVERNIGHT HOURS PROGRESS. HOWEVER...THE DIRECTION OF FLOW WILL
NOT BE FAVORABLE FOR THE ADVECTION OF THE MOISTURE CURRENTLY OVER
THE MIDDLE AND UPPER OHIO VALLEY. THE 00Z KILN SOUNDING INDICATED
SATURATION BETWEEN 925MB AND 875MB...CAPTURED WELL ON THE NAM12
AND RAP13...BUT VERY POORLY ON THE GFS AND ECMWF. THE EROSION OF
THE SOUTHERN/WESTERN EDGE OF THESE CLOUDS HAS SLOWED OR
STOPPED...AND THE FORECAST FOR THE OVERNIGHT WILL REMAIN VERY
CLOUDY. HOWEVER...SOME SLIGHT WARMING IS EXPECTED TO BEGIN AT
900MB AFTER 06Z...WHICH MAY BE ENOUGH TO LEAD TO SOME BREAKS IN
THE CLOUDS CLOSER TO MORNING.
PREVIOUS FORECAST >
ELONGATED MID LEVEL LOW OVER THE GREAT LAKES TO SHIFT OFF INTO NEW
ENGLAND. A FEW ISOLD LINGERING FLURRIES IN THE LOW LEVEL CAA WILL
COME TO AN END EARLY. MID LEVEL FLOW BECOMES BRIEFLY NW AHEAD OF AN
UPSTREAM S/W RIDGE. SFC HIGH PRESSURE TO NOSE INTO THE OHIO VALLEY
OVERNIGHT IN REGION OF H5 CONFLUENCE. 12Z ILN SOUNDING SHOWS LOW
LEVEL MOISTURE TRAPPED BELOW AN INVERSION AROUND 850 MB. GFS IS
AGGRESSIVE WITH CLEARING LOW LEVEL MOISTURE. NAM AND RAP SOLNS KEEP
CLOUDS OVERNIGHT. WILL ALLOW A FEW BREAKS OVER THE SOUTH/SOUTHWEST
BUT LEAN TOWARD THE NAM/RAP SOLN. TEMPERATURES WILL BE CLOSE TO
NORMAL WITH LOWS FROM THE MID 20S NORTH TO THE UPPER 20S SOUTH.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
MID LEVEL S/W TO RIPPLE QUICKLY EAST FROM THE CENTRAL PLAINS
THROUGH THE OHIO VALLEY THURSDAY. THIS WEAK SHORTWAVE IS DAMPENING
AND CROSSING OVER THE SFC RIDGE. FORCING IS VERY WEAK AND IN THE
MID LEVELS. A FLURRY OR SPRINKLE IS NOT OUT OF THE QUESTION FROM A
MID DECK. FLURRIES/SPRINKLES ALREADY IN THE FORECAST...SO WILL
CONTINUE. TEMPERATURES WILL BE BELOW NORMAL WITH HIGHS FROM THE
LOWER 30S NORTH TO THE MID/UPR 30S SOUTH.
IN WESTERLY MID LEVEL FLOW REGIME...SFC HIGH PRESSURE TO BUILD
ACRS THE GREAT LAKES/OHIO VALLEY THURSDAY NIGHT/FRIDAY. A FEW
FLURRIES WILL REMAIN POSSIBLE THURSDAY EVENING BUT WILL COME TO AN
END WITH THE PASSAGE OF THE S/W. AS THE HIGH BUILD NOSES IN
EXPECT SOME PARTIAL CLEARING THURSDAY NIGHT. LOWS EXPECTED TO
RANGE FROM THE MID 20S NORTH TO THE UPPER 20S SOUTH.
EXPECT TO SEE MORE SUNSHINE FRIDAY WITH AN INCREASE IN HIGH LEVEL
MOISTURE LATE IN THE DAY. FRIDAYS HIGHS FROM THE MID 30S NORTH TO
NEAR 40 SOUTH.
CLOUDS WILL THICKEN AND INCREASE FRIDAY NIGHT AS SYSTEM APPROACHES
FROM THE SOUTHWEST. WILL KEEP FCST DRY FRIDAY NIGHT AS CONSENSUS
DOES NOT BRING MOISTURE IN UNTIL SATURDAY. LOWS FRIDAY NIGHT TO
RANGE FROM THE UPPER 20S NORTH TO THE LOWER 30S FAR SOUTH.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
FOR SATURDAY...LOOKS LIKE WE COULD SEE SNOW CHANGING TO RAIN AS LOW
PRESSURE TRAVELS NEAR THE GULF COAST. THE LOW HAS TRENDED FARTHER TO
THE SOUTH SO CUT BACK ON POPS AND PRECIP AMOUNTS. HIGH PRESSURE AND
A COOL AIRMASS SHOULD ALLOW DRY WEATHER ON SUNDAY. LIGHT PRECIP WILL
BE POSSIBLE MONDAY EXTENDING FROM A TROUGH ALONG THE EAST COAST.
WE MAY BEGIN TO FEEL THE EFFECTS OF A POWERFUL LOW PRESSURE SYSTEM
ON TUESDAY. HAVE LESS THAN AVERAGE AMOUNT OF CONFIDENCE DUE TO MODEL
DIFFERENCES FROM RUN TO RUN. AT THIS POINT IT APPEARS THE LOW WILL
DEVELOP OVER THE SOUTHERN PLAINS ON TUESDAY...BEFORE LIFTING THROUGH
OHIO TO THE GREAT LAKES ON WEDNESDAY. THE LOW MAY FEATURE A VERY
TIGHT PRESSURE GRADIENT SURROUNDING ITS DEEP CENTER...PRODUCING
STRONG WINDS. COPIOUS MOISTURE FEEDING FROM THE TROPICS AND FROM THE
ATLANTIC OCEAN COULD ADVECT AROUND THE LOW. CURRENT TEMPERATURE
FORECAST ALLOWS RAIN TUESDAY INTO WEDNESDAY...CHANGING TO SNOW LATER
WEDNESDAY AS COLDER AIR WRAPS IN BEHIND THE LOW.
TEMPERATURES WILL BE RELATIVELY CLOSE TO NORMAL FOR THE MOST PART.
HIGHS ARE FORECAST TO BE IN THE MID AND UPPER 30S SATURDAY...THEN A
COUPLE DEGREES WARMER FOR SUNDAY AND MONDAY UNDER NEUTRAL TO WEAK
WARM ADVECTION. READINGS ON TUESDAY AND WEDNESDAY WILL BE DEPENDENT
ON THE POSITION OF THE ANTICIPATED STRONG LOW. WARM ADVECTION AHEAD
OF THE LOW COULD BRING HIGHS UP INTO THE MID 40S ON TUESDAY...OR
EVEN HIGHER IF THE WARMER MEX GUIDANCE VERIFIES. HIGHS COULD SLIP TO
AROUND 40 ON WEDNESDAY IN COLD ADVECTION BEHIND THE LOW.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A PERSISTENT MVFR CLOUD DECK IS LIKELY TO REMAIN IN PLACE ACROSS
THE TAF SITES INTO THE AFTERNOON. AT THAT TIME THE DECK SHOULD
BREAK AS A WEAK UPPER LEVEL SYSTEM APPROACHES THE AREA. HOWEVER
THE REPRIEVE WILL BE SHORT LIVE AS THE MVFR CIGS SHOULD RETURN
DURING THE EVENING. DURING THIS BREAK IN THE MVFR CIGS THERE WILL
BE MULTIPLE LAYERS OF CLOUDS AOB FL050 IN ASSOCIATION WITH THE
NEXT SYSTEM. WHILE MOISTURE WITH THIS NEXT SYSTEM WILL BE LACKING
IN TERMS OF PCPN...FLURRIES ARE EXPECTED THIS AFTERNOON AND
EVENING. SINCE NO VSBY RESTRICTIONS ARE EXPECTED AND THE TIMING
DURING THIS PERIOD WILL BE VARIABLE HAVE NOT INCLUDED THIS MENTION
IN THE FCST.
W WINDS OF UNDER 10 KNOTS ARE EXPECTED THROUGH THE FCST PERIOD.
OUTLOOK...MVFR CEILINGS MAY CONTINUE INTO FRIDAY. MVFR CEILINGS
AND VISIBILITIES ARE POSSIBLE ON SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...AR
NEAR TERM...HATZOS/AR
SHORT TERM...AR
LONG TERM...CONIGLIO
AVIATION...HAYDU
AREA FORECAST DISCUSSION
NWS MEDFORD OR
918 PM PST WED DEC 17 2014
.DISCUSSION...THE REMNANTS OF AN OCCLUDED FRONT ARE MOVING EAST
THIS EVENING WITH A SLOW MOVING BAND OF LIGHT PRECIPITATION
ROUGHLY NOW JUST EAST OF THE I-5 CORRIDOR THROUGH SOUTHERN OREGON
AND SISKIYOU COUNTY. PRECIPITATION HAS BEEN WIDESPREAD ON THE WEST
SIDE WITH AMOUNTS IN THE LAST 3 HOURS LARGELY BELOW 0.10 INCHES.
MEANTIME...SHOWERS IN KLAMATH AND EASTERN SISKIYOU COUNTY HAVE
BEEN ISOLATED TO SCATTERED AND WILL BE GREATEST IN NUMBER DURING
THE NEXT 3 HOURS. THE SNOW LEVEL IS AROUND 4500 FEET AND SNOW
AMOUNTS OVER THE CASCADES AND EAST SIDE ARE EXPECTED TO BE NOT
MUCH MORE THAN A DUSTING...UP TO A HALF OF AN INCH. SHOWERS AND
SNOW SHOWERS WILL TAPER OFF OVERNIGHT INTO THURSDAY MORNING.
THE 00Z GFS HAS ARRIVED AND INDICATES LIGHT RAIN TO ARRIVE AT THE
COOS COUNTY COAST DURING THURSDAY AFTERNOON...IN ADVANCE OF THE
NEXT FRONT. OTHERWISE, THERE WILL BE A MIX OF CLOUDS ACROSS THE
AREA INCLUDING MORNING VALLEY LOW CLOUDS AND PATCHY FOG. FRONTAL
PRECIPITATION WILL BE FOCUSED ON THE THURSDAY NIGHT PERIOD WITH
MODERATE TO HEAVY PRECIPITATION FOR THE CURRY COUNTY AND NORTHERN
CALIFORNIA COAST INTO JOSEPHINE AND SISKIYOU COUNTIES. THE SNOW
LEVEL IS FORECAST TO BEGIN THE EVENING AT AROUND 6000 TO 6500 FEET
THEN FALL TO AROUND 4000 TO 5000 FEET AS PRECIPITATION AMOUNTS
DIMINISH AND PRECIPITATION TRANSITIONS TO SHOWERS ON FRIDAY
MORNING...DIMINISHING DURING THE DAY. THUS, THE SNOW LEVEL WILL BE
ABOVE THE MAJOR PASSES DURING THE MAJORITY OF THE EVENT.
A STRONG WARM FRONT IS STILL INDICATED TO ARRIVE SATURDAY WITH
WIDESPREAD PRECIPITATION AT LEAST THROUGH SATURDAY EVENING BUT
ALSO RISING SNOW LEVELS THAT WILL BE WELL ABOVE THE PASSES.
THIS FRONT WILL LINGER THROUGH THE WEEKEND WITH MODERATE TO HEAVY
PRECIPITATION LATE SATURDAY NIGHT INTO MONDAY MAINLY FROM ROSEBURG
NORTHWARD.
&&
.AVIATION...BASED ON THE 18/00Z TAF CYCLE...VFR CONDITIONS WILL
PREVAIL INITIALLY WITH AREAS OF HIGHER TERRAIN OBSCURED...EXCEPT FOR
WESTERN AND SOUTH CENTRAL SISKIYOU COUNTY...WHERE AREAS OF MVFR CIGS
WILL PREVAIL THROUGH THURSDAY MORNING. WIDESPREAD MVFR CIGS WILL
RETURN TO THE WEST SIDE VALLEYS OVERNIGHT...AND WITH INCREASING
WINDS AND THE MVFR DECKS FOG FORMATION SHOULD BE LIMITED. ALL AREAS
WILL CLEAR TO VFR BY THURSDAY AFTERNOON. /SVEN
&&
.MARINE...UPDATED 645 PM PST WED DEC 17 2014...WEAK LOW PRESSURE
SYSTEMS WILL MOVE THROUGH THE AREA TONIGHT. SOUTHWEST SWELL
DOMINATED SEAS WILL REMAIN MOSTLY AT OR ABOVE 10 FEET TODAY.
THURSDAY INTO THURSDAY NIGHT A STRONGER FRONTAL SYSTEM WILL LIKELY
BRING GALE FORCE WINDS AND VERY STEEP SOUTHWEST SEAS. LONG PERIOD
WEST SWELL WILL BEGIN TO ARRIVE IN THE PREDAWN HOURS FRIDAY MORNING.
IT WILL PEAK FRIDAY NIGHT AT AROUND 20 FEET AT 20 SECONDS. SERIES OF
LARGE LONG PERIOD SWELL CONTINUE TO MOVE INTO THE REGION THROUGH
EARLY NEXT WEEK. A WARM FRONT WILL MOVE THROUGH FRIDAY
NIGHT...FOLLOWED BY A COLD FRONT SATURDAY. OFFSHORE HIGH PRESSURE
WILL BUILD SATURDAY NIGHT INTO SUNDAY. /SVEN
&&
.PREV DISCUSSION... /ISSUED 206 PM PST WED DEC 17 2014/
DISCUSSION...ANOTHER WEAK UPPER TROUGH IS NEAR THE COAST AND THIS
WILL MOVE INLAND THIS EVENING. CURRENT RADAR SHOWS TWO AREAS OF
SCATTERED SHOWERS. THE FIRST IS IN NORTHEAST SISKIYOU AND KLAMATH
COUNTY AND THE SECOND IS MOVING TOWARDS THE COAST. THIS SECOND
FEATURE WILL MOVE INLAND THIS EVENING AND BRING SCATTERED SHOWERS
OVER NORTHERN CAL AND SOUTHWEST OREGON. THE LATEST RAP MODELS
DEPICTS THE PLACEMENT OF THE PRECIPITATION WELL AND WILL FOLLOW THIS
FOR THIS EVENING. THE UPPER TROUGH WILL WEAKEN AS IT MOVES EAST AND
SHORTWAVE RIDGING BEGINS TO BUILD IN OVERNIGHT. THIS SHOULD SHUT OFF
THE SHOWER ACTIVITY OVER MOST OF THE AREA, ALTHOUGH SOME RESIDUAL
SHOWERS COULD LINGER IN SOUTHEAST SISKIYOU AND MODOC COUNTIES.
WE`LL CATCH A DRY BREAK ON THURSDAY WITH THE RIDGE AXIS OVER THE
AREA, BUT THIS WILL BE SHORT LIVED. THE MODELS SHOW A STRONGER FRONT
APPROACHING THE AREA THURSDAY AFTERNOON BRINGING INCREASING SOUTH
WINDS OVER THE MARINE WATERS WHICH ARE EXPECTED TO GET CLOSE TO
GALES. PRECIPITATION COULD ALSO REACH THE COAST AS EARLY AS THURSDAY
AFTERNOON. THE FRONT WILL MOVE INLAND THURSDAY NIGHT BRINGING
MODERATE TO HEAVY PRECIPITATION OVER THE USUAL SUSPECTS...THE COAST
RANGE...COASTAL MOUNTAINS AND CASCADES. HOWEVER THE MODELS ARE IN
GOOD AGREEMENT THE FRONT WILL BE A QUICK MOVER AND SO WE WON`T GET
SIGNIFICANT PRECIPITATION AMOUNTS. SNOW LEVELS WILL START OUT HIGH
THURSDAY NIGHT, BUT WILL DROP TO AROUND 4500 FEET EARLY FRIDAY
MORNING. SO IT`S A GOOD BET THE MOUNTAIN PASSES WILL GET
ACCUMULATING SNOW STARTING LATE THURSDAY NIGHT THROUGH FRIDAY
MORNING. CURRENT THINKING IS CRATER LAKE COULD PICK UP AT LEAST 6
INCHES OR MORE AND A FEW INCHES ARE POSSIBLE OVER SISKIYOU SUMMIT
AND HIGHWAY 140. KEEP IN MIND THE DETAILS ON THIS WILL CHANGE, SO
STAY TUNED FOR THE LATEST UPDATES.
THE ABOVE MENTIONED FRONT WILL QUICKLY MOVE THROUGH FRIDAY AND WE`LL
CATCH A RELATIVE BREAK IN PRECIPITATION FRIDAY AFTERNOON AND EVENING.
BUT AGAIN THIS WILL BE SHORT LIVED. THE MODELS ARE IN PRETTY GOOD
AGREEMENT SHOWING A STRONG WARM FRONT ARRIVING AT THE COAST LATE
FRIDAY NIGHT AND MOVING OVER THE AREA SATURDAY. THIS FRONT HAS A LOT
OF JUICE WITH IT AND HEAVY PRECIPITATION WILL LIKELY IMPACT THE
COAST...COAST RANGE...COASTAL MOUNTAINS AND CASCADES. MODERATE TO
HEAVY PRECIPITATION WILL ALSO IMPACT MUCH OF THE WESTSIDE VALLEYS. OF
NOTE THE IVT TRANSPORT (WHICH IS GFS BASED) PUTS THE HIGHEST VALUES
IN CENTRAL AND NORTHWEST OREGON. EVEN THE GEFS ENSEMBLE MEAN IS
SIMILAR TO THE OPERATIONAL GFS. ADDITIONALY, THE UPPER FLOW IS
ALMOST DUE WEST WHICH WILL SQUEEZE OUT EVEN MORE MOISTURE ALONG THE
COAST RANGE. ALSO WINDS WILL INCREASE AHEAD OF THE FRONT AND THERE
IS A CHANCE FOR GALE FORCE WINDS OVER THE MARINE WATERS AND MODERATE
TO STRONG WINDS OVER THE COAST AND HEADLANDS. IF THAT WEREN`T ENOUGH
THERE IS CONCERN FOR SNOW EAST OF THE CASCADES AS THE WARM FRONT
ARRIVES. MODEL SOUNDINGS SUPPORT THE IDEA THAT ENOUGH COLD AIR WILL
BE PRESENT NEAR THE SURFACE AND THIS IN COMBINATION WITH OVERRUNNING
PRECIPITATION COULD BRING A PERIOD OF SNOW SATURDAY MORNING.
STRONG WESTERLY FLOW CONTINUES SATURDAY NIGHT WITH THE HEAVIEST
PRECIPITATION WEST OF THE CASCADES, BUT SNOW LEVELS WILL JUMP UP TO
AROUND 7000 FEET SATURDAY AFTERNOON AND REMAIN HIGH SATURDAY NIGHT.
-PETRUCELLI
LONG-TERM FORECAST...SUNDAY THROUGH WEDNESDAY. A BROAD LONG WAVE
RIDGE WILL BE IN PLACE AT THE BEGINNING OF THE EXTENDED PERIOD WITH
WITH GENERALLY NORTHWEST FLOW ALOFT. SHORT WAVES RIDING OVER THE TOP
OF THE RIDGE WILL WEAKEN IT FROM SUNDAY NIGHT ON...BUT IT WILL
REMAIN IN PLACE THROUGH TUESDAY. THE FLOW ALOFT WILL BECOME MORE
ZONAL TUESDAY.
THIS PATTERN WILL FORCE THE MAIN STORM TRACK TO THE NORTH OF THE
MEDFORD CWA...BUT THE AREA WILL STILL CATCH THE SOUTHERN END OF
SEVERAL SYSTEMS WHICH WILL MOVE ONSHORE DURING THIS INTERVAL. THE
STRONGEST OF THESE SYSTEMS WILL MOVE ONSHORE SATURDAY AFTERNOON AND
EVENING...AND WILL BE OVER THE CWA SUNDAY. REINFORCING SHORT WAVES
WILL KEEP THE PRECIPITATION GOING THROUGH MOST OF MONDAY. THE BULK
OF THE ASSOCIATED PRECIPITATION WILL FALL ALONG THE COAST...COAST
RANGE...AND UMPQUA BASIN. AMOUNTS WILL BE SIGNIFICANT BUT NOT
EXCESSIVE...NO FLOODING PROBLEMS ARE ANTICIPATED. SNOW LEVELS WILL
BE ABOVE 7000 FEET.
MONDAY NIGHT INTO TUESDAY LOOK TO BE MOSTLY DRY WITH NEARLY ALL THE
ACTION TO THE NORTH OF THE AREA.
THE RIDGE WILL BREAK DOWN WEDNESDAY AND A LONG WAVE TROUGH WILL
BEGIN TO DIG OFFSHORE. THIS CHANGE IN PATTERN WILL SUPPORT A FRONT
MOVING ONSHORE WEDNESDAY. THIS WILL BE THE WETTEST SYSTEM OF THE
EXTENDED PERIOD IF THE CURRENT EC/GFS MODEL SOLUTIONS PAN OUT. SNOW
LEVELS MAY ALSO FALL AS LOW AS 4000 FEET BEHIND THE FRONT WEDNESDAY
NIGHT...SO SNOW MAY RETURN TO THE PASSES AROUND THAT TIME. -JRS
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS FROM 4 AM
TO 10 PM PST THURSDAY FOR PZZ350-356-370-376.
HAZARDOUS SEAS WARNING FROM 11 AM THURSDAY TO 4 AM PST
FRIDAY FOR PZZ350-356-370-376.
GALE WARNING FROM 10 AM TO 10 PM PST THURSDAY FOR
PZZ350-356-370-376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 AM TO
10 AM PST THURSDAY FOR PZZ350-356-370-376.
$$
DW/DW/SBN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1158 PM EST WED DEC 17 2014
.SYNOPSIS...
BRISK WESTERLY WINDS WILL USHER IN COLDER AIR ALONG WITH SCATTERED
MAINLY MOUNTAIN SNOW SHOWERS THROUGH THE END OF THE WEEK. A WEAK
LOW PRESSURE AREA IS EXPECTED TO MOVE WELL SOUTH OF THE REGION
THIS WEEKEND. THERE ARE INDICATIONS THAT THE WEATHER PATTERN COULD
TURN MORE UNSETTLED FOR NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
NO REAL CHANGES MADE WITH THIS UPDATE OTHER THAN SOME MINOR
TEMPERATURE TWEAKS.
BEST CHANCE OF SOW SHOWERS WILL BE OVER THE MORE TRADITIONAL HIGH
TERRAIN AREAS OF THE WEST AND NORTH AS WE ESTABLISH A COLD WNW
FLOW OVER THE REGION. HRRR SHOWS PRECIP REMAINING CONFINED TO
MAINLY NWRN PA THROUGH THE OVERNIGHT AND LATEST OPERATIONAL
GUIDANCE SUPPORTS THIS.
WEST TO NW WINDS WILL AVERAGE 10-15 KTS WITH GUSTS IN THE 20S
LATE TODAY THROUGH TONIGHT.
LOW TEMPS AT DAYBREAK THURS WILL BE NEAR 20F ACROSS THE HIGHER
TERRAIN OF THE NORTH AND WEST...AND IN THE MID TO UPPER 20S
THROUGHOUT THE SUSQ VALLEY.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
COLD AIR WILL STAY IN PLACE ACROSS THE FCST AREA THURSDAY INTO
FRIDAY.
THURSDAY...WINDS AT THE SFC AND ALOFT WILL VEER JUST SLIGHTLY TO
THE NORTHWEST. SPEEDS OF 10-15 MPH AND GUSTS INTO THE L20S ARE
POSSIBLE OVER THE MOUNTAINS. LITTLE OF NO CHANGE IN THE BLANKET OF
STRATUS AND STRATOCU CLOUDS IS EXPECTED THURSDAY AND THU
NIGHT...AND THE RELATIVELY SHALLOW COLD AIR BLOWING OVER THE LOWER
GLAKES WILL CREATE MORE SHSN ACROSS THE NRN AND WRN MTNS.
ACCUMULATIONS WILL BE MINOR...AND CONFINED TO THE FAR NW AND VERY
HIGHEST ELEVATIONS. AS STATED BY PREVIOUS SHIFTS NO MORE THAN 2
INCHES IS EXPECTED THROUGHOUT THE SNOWBELT OF NW WARREN COUNTY ON
THE HIGH END...SO NO LES ADVISORIES PLANNED ATTM. GLIMPSES OF
SUN MAY DEVELOP AGAIN ACROSS THE LOWER SUSQ...NUDGING TEMPS INTO
THE LOWER 40S /NEAR NORMAL FOR MID DEC/. MAX TEMPS ACROSS THE NRN
AND WRN MTNS WILL BE IN THE U20S TO L30S.
SIMILAR TEMPS AND SKY COVER EXPECTED AGAIN FOR THU NIGHT WITH
ISOLATED TO SCTD MTN SNOW SHOWERS. LITTLE IN THE WAY OF
ADDITIONAL SNOW ACCUM IS EXPECTED THOUGH AS MOISTURE WILL
CONTINUE TO BE QUITE SHALLOW WITH THE SUBSIDENCE INVERSION BASE
AOB 5 KFT AGL. A FEW HIGHLY LOCALIZED AMOUNTS IN THE 2-3 INCH
RANGE ARE POSSIBLE ACROSS THE FAVORED PERENNIAL SNOWBELT OF WARREN
COUNTY DURING THE 24 HOUR PERIOD ENDING 12Z FRI.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE PATTERN WILL REMAIN SEASONABLY COLD AND BRISK THROUGH THE END
OF THE WEEK. LARGE SCALE SUBSIDENCE ASSOCIATED WITH SURFACE HIGH
MIGRATING EASTWARD FROM THE UPPER MIDWEST ACROSS ONTARIO/QUEBEC
SHOULD BRING AN END TO NUISANCE/MINOR SNOW SHOWER ACTIVITY AND
LINGERING FLURRIES OVER THE NW ALLEGHENIES BY FRI NGT. CLEAR SKIES
AND CALM/LIGHT WINDS SHOULD ALLOW MIN TEMPS TO DIP INTO THE TEENS
IN THE NORTHERN MTNS SATURDAY MORNING.
CONCERNING THE WEEKEND SYSTEM...
HOPES FOR A SIGNIFICANT STORM THIS WEEKEND CONTINUE TO FADE WITH
THE LATEST MODELS CONTINUING TO SHOW A MUCH WEAKER/SUPPRESSED AND
DISJOINTED SYSTEM AS THE CONSENSUS SOLUTION. IN ADDITION..THE
RISK FOR ACCUMULATING LIGHT SNOW HAS ALSO NOTABLY DECREASED...BUT
NOT TOTALLY EVAPORATED. THAT SAID THERE IS STILL A NON-TRIVIAL
CHANCE THAT MOST PRECIP REMAINS SOUTH OF PA AND THE WEEKEND TURNS
OUT DRY FOR MOST LOCATIONS. EARLY WEEK MODEL SIMULATIONS FOR A
MAJOR STORM HAVE ALL BUT TRENDED TO A VIRTUAL NON EVENT FOR OUR
AREA.
THE PROGRESSIVE SPLIT STREAM ENERGY ALOFT MOVING EAST FROM THE
MID MS VLY NEVER REALLY ORGANIZES AS IT ATTEMPTS TO OVERRUN A
RETREATING AREA OF MODESTLY STRONG HP/RIDGING OVER THE NORTHEAST
AND EASTERN CANADA. AS SUCH DOWNPLAYED PCPN POTENTIAL AND TRIMMED
POPS BACK BY 10-20 PCT. THE NEW WRINKLE IN THIS FORECAST CYCLE IS
FOR A SECOND PIECE OF ENERGY /WHAT APPEARS TO BE THE MAIN SFC LOW/
LIFTING NORTH FROM NEAR THE FL/GA COAST AND TRACKING UP/OFFSHORE
THE EAST COAST SUN THRU TUE.
THE SPLIT FLOW PATTERN OVER THE CONUS IS EXPECTED TO BECOME HIGHLY
AMPLIFIED WITH A VERY DEEP NEGATIVELY TILTED TROUGH EVOLVING EAST
OF THE ROCKIES...LIKELY SPAWNING AN INTENSE SFC LOW OVER THE
GREAT LAKES/MID ATLANTIC/NORTHEAST REGIONS AROUND THE CHRISTMAS
EVE TIME FRAME. FOR WHAT ITS WORTH...BOTH THE 17/12Z GFS AND EC
ARE FORECASTING A RECORD LOW MSLP SUB 970MB CYCLONE INVOF LAKE
HURON AT 00Z ON 25 DEC. THIS SYSTEM WILL LIKELY GATHER MORE AND
MORE ATTENTION AS WE MOVE CLOSER TO THE HOLIDAY. THE GOOD NEWS FOR
TRAVELERS/BAD NEWS FOR SNOW CROWS IS THAT CURRENT PROJECTIONS
WOULD PLACE CENTRAL PA INITIALLY IN THE "WARM" SIDE OF THE DEEP
STORM FAVORING RAIN VS. SNOW. IT ALSO LOOKS QUITE WINDY ASSUMING
THE DEEP LOW VERIFIES.
&&
.AVIATION /05Z THURSDAY THROUGH MONDAY/...
WIDESPREAD STRATO CU AND PERSISTENT MVFR TO IFR CIGS WITH
ISOLATED-SCATTERED AND GENERALLY BRIEF MVFR TO IFR VSBYS IN SNOW
SHOWERS WILL OCCUR ACROSS THE NW MTNS AND LAUREL HIGHLANDS /INVOF
KBFD AND KJST/ TONIGHT INTO THE MORNING HOURS. CONDITIONS ACROSS
THE CENTRAL MTNS WILL VARY BETWEEN LOW END VFR...AND MVFR CIGS.
GUSTY WEST TO WNW WINDS /UP AROUND 25 KTS AT TIMES/ WILL ADD SOME
MECHANICAL TURBULENCE DURING TAKEOFF AND FAP TO REGIONAL AIRFIELDS
THIS EVENING THROUGH THURSDAY. VFR CIGS AND VSBYS SHOULD CONTINUE
OVERNIGHT THROUGH THE EASTERN TAF SITES.
OUTLOOK...
THU-FRI...MVFR CIGS POSS NW. OTHERWISE NO SIG WX EXPECTED.
SAT-SUN...LIGHT SNOW/REDUCED VSBY POSSIBLE ...MAINLY ALONG THE MD
BORDER.
MONDAY...MAINLY VFR. HOWEVER...AREAS OF MVFR STRATO CU ARE
POSSIBLE IN DEVELOPING SERLY LOW LEVEL FLOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1039 PM MST WED DEC 17 2014
.UPDATE...
ISSUED AT 907 PM MST WED DEC 17 2014
DECIDED TO ISSUE A DENSE FOG ADVISORY FOR THE PLATTE RIVER VALLEY
BETWEEN TORRINGTON AND BRIDGEPORT. SFC OBSERVATIONS AND AREA WEB
CAMS CONFIRM VISIBILITIES OF ONE QUARTER OF A MILE OR LESS AT TOR
AND BFF AS OF 03Z THIS EVE. BIGGEST QUESTION IS JUST HOW LONG THIS
WILL LAST AS DRIER AIR IS TRYING TO WORK IN. RECENT HIGHRES MODEL
RUNS ARE TOO QUICK TO SHIFT WINDS AROUND TO THE WEST IN THIS LOW
GRADIENT PATTERN...SO AM CONFIDENT THE PLATTE RIVER VALLEY WILL
HANG ON TO A MOIST UPVALLEY FLOW OVERNIGHT. WITH SIGNIFICANT SNOW
COVER IN SCOTTS BLUFF COUNTY...THESE AREAS SHOULD HAVE NO PROBLEM
STAYING IN THE SOUP FOR SEVERAL HOURS. THE 01Z HRRR RUN SHOWS VSBY
LESS THAN ONE HALF MILE PERSISTING THROUGH AT LEAST 12Z AND FCST
SOUNDINGS SHOW EXCELLENT LLVL MOISTURE DURING THIS TIME. FREEZING
FOG HAS ALSO HAD A TENDENCY TO CREATE LIGHT ICING THE PAST FEW
NIGHTS...SO FELT AN ADVISORY WAS WARRANTED WITH THE ADDED RISK TO
TRAVEL. ALL OTHER ASPECTS OF THE FORECAST LOOK GOOD. UPDATES AND
NPW HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 351 PM MST WED DEC 17 2014
FOG AND LOW STRATUS LOOKS TO RETURN TONIGHT ACROSS THE PANHANDLE
AND ALSO CENTRAL AND WESTERN PORTIONS OF CARBON COUNTY AS
FORECAST SOUNDINGS SHOW NEARLY SATURATED LLVLS WITH LIGHT SSW
SURFACE WINDS IN PLACE FOR THESE AREAS. UPPER LEVEL WINDS WILL
REMAIN LIGHT AS WELL WITH LITTLE IN THE MEANS OF ANY DISTURBANCES
ALOFT DISRUPTING THE LOWER LEVELS...SO PERSISTENCE FORECAST SEEMS
REASONABLE. LIGHT SNOW WILL CONTINUE OVER THE MOUNTAINS IN THIS
PATTERN AS WELL...WITH GENERALLY LESS THAN AN INCH OF ACCUMULATION
EXPECTED. THINKING THAT THE FOG AND LOW STRATUS WILL NOT STICK
AROUND AS LONG TOMORROW AS TODAY/YESTERDAY AS A SHORTWAVE TROUGH
APPROACHES FROM THE PAC NW AND DEEPENS THE LEESIDE SFC PRESSURE
TROUGH...THUS INCREASING WEST WINDS ACROSS THE CWA AND NUDGING THE
LLVL MOISTURE EASTWARD. THE EXCEPTION COULD BE OUT WEST IN THE
LOWER ELEVATIONS OF CARBON COUNTY WHERE THE WESTERLY WINDS COULD
MAINTAIN INFLUX OF LLVL MOISTURE TO THIS AREA. LIKELY TO SEE WIND
GUSTS OF 30 TO 35 MPH IN THE WIND PRONE AREAS ALONG AND WEST OF
THE LARAMIE RANGE THROUGH THE DAY AS THE PRESSURE GRADIENT
STRENGTHENS IN ADVANCE OF THE UPPER TROUGH...WITH WARMING TEMPS
ACROSS THE EASTERN PLAINS WITH THESE DOWNSLOPE WINDS IN PLACE.
WINDS WILL INCREASE SLIGHTLY FOR THE WIND PRONE AREAS FOR TOMORROW
NIGHT AND FRIDAY AS THE UPPER LEVEL TROUGH MOVES OVERHEAD WITH
GUSTS OF 40 TO 50 MPH POSSIBLE THROUGH EARLY FRIDAY AFTERNOON.
EXPECTING LIGHT SNOW SHOWERS TO CONTINUE THROUGH THIS TIME ALONG
WITH SLIGHTLY WARMER TEMPS ACROSS THE PLAINS.
OTHERWISE...CONDITIONS WILL REMAIN DRY AND BREEZY THROUGH FRIDAY
NIGHT.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 351 PM MST WED DEC 17 2014
RATHER ZONAL FLOW SATURDAY WILL BECOME NWLY SATURDAY NIGHT AND
SUNDAY AS RIDGING AMPLIFIES ALONG THE WEST COAST. MAINLY DRY
OUTSIDE OF THE MTNS WHERE OROGRAPHICS SHOULD ALLOW FOR SOME SNOW
SHOWERS BOTH DAYS. LOOKING RATHER WINDY SAT NIGHT AND SUNDAY AS AN
UPPER JET MOVES INTO THE PACIFIC NW INTO THE NRN ROCKYS AND SFC
PRESSURE FALLS OCCUR OVER THE HIGH PLAINS AHEAD OF SHORTWAVE
ENERGY OVER THE PACIFIC NW. A COOL FRONT SHOULD THEN PASS ACROSS
LATE SUNDAY WITH A DECENT SURGE OF MOISTURE INCREASING SNOW SHOWER
ACTIVITY ESPECIALLY OVER THE SW PART OF THE CWA SUNDAY NIGHT AND
MONDAY. COOL AND SOMEWHAT BREEZY CONDITIONS EXPECTED FOR TUESDAY
AND WEDS AS THE CWA REMAINS UNDER NWLY FLOW ALOFT WITH SNOW
SHOWERS CONTINUING OVER THE HIGHER MTNS AS MOISTURE RIDES UP
FACING SLOPES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1031 PM MST WED DEC 17 2014
IFR/LIFR CONDITIONS WILL CONTINUE THROUGH ABOUT 15Z FOR THE NEB
PANHANDLE TERMINALS. VSBYS IN THE PLATTE RIVER VALLEY MAY BE LESS
THAN ONE QUARTER OF A MILE...ESPECIALLY AT KBFF/KTOR. CIGS WILL BE
AT OR NEAR AIRPORT MINIMUMS AROUND 200-300 FT AGL. CONDITIONS WILL
QUICKLY IMPROVE BY LATE THU MORNING OR EARLY AFTERNOON. WEST WINDS
WILL KEEP WIDESPREAD FOG AT BAY OVER SOUTHEAST WYO. HOWEVER PATCHY
DENSE FOG CANNOT BE RULED OUT OVER WESTERN CARBON COUNTY/KRWL OVER
THE NEXT FEW HOURS.
&&
.FIRE WEATHER...
ISSUED AT 351 PM MST WED DEC 17 2014
NO FIRE WEATHER CONCERNS THROUGH FRIDAY. COLD TEMPERATURES
WILL KEEP SNOW COVER ON THE GROUND ACROSS MUCH OF THE REGION.
AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 45 PERCENT AND
WINDS WILL BE WEAK THROUGH THURSDAY. BY THURSDAY NIGHT AND
FRIDAY...WEST WINDS WILL BECOME BREEZY FOR AREAS ALONG AND WEST
OF THE LARAMIE RANGE.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 8 AM MST THURSDAY FOR WYZ108.
NE...DENSE FOG ADVISORY UNTIL 8 AM MST THURSDAY FOR NEZ003-019-021-
096.
&&
$$
UPDATE...CLH
SHORT TERM...RJM
LONG TERM...RE
AVIATION...CLH
FIRE WEATHER...RJM
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
919 PM MST WED DEC 17 2014
.UPDATE...
ISSUED AT 907 PM MST WED DEC 17 2014
DECIDED TO ISSUE A DENSE FOG ADVISORY FOR THE PLATTE RIVER VALLEY
BETWEEN TORRINGTON AND BRIDGEPORT. SFC OBSERVATIONS AND AREA WEB
CAMS CONFIRM VISIBILITIES OF ONE QUARTER OF A MILE OR LESS AT TOR
AND BFF AS OF 03Z THIS EVE. BIGGEST QUESTION IS JUST HOW LONG THIS
WILL LAST AS DRIER AIR IS TRYING TO WORK IN. RECENT HIGHRES MODEL
RUNS ARE TOO QUICK TO SHIFT WINDS AROUND TO THE WEST IN THIS LOW
GRADIENT PATTERN...SO AM CONFIDENT THE PLATTE RIVER VALLEY WILL
HANG ON TO A MOIST UPVALLEY FLOW OVERNIGHT. WITH SIGNIFICANT SNOW
COVER IN SCOTTS BLUFF COUNTY...THESE AREAS SHOULD HAVE NO PROBLEM
STAYING IN THE SOUP FOR SEVERAL HOURS. THE 01Z HRRR RUN SHOWS VSBY
LESS THAN ONE HALF MILE PERSISTING THROUGH AT LEAST 12Z AND FCST
SOUNDINGS SHOW EXCELLENT LLVL MOISTURE DURING THIS TIME. FREEZING
FOG HAS ALSO HAD A TENDENCY TO CREATE LIGHT ICING THE PAST FEW
NIGHTS...SO FELT AN ADVISORY WAS WARRANTED WITH THE ADDED RISK TO
TRAVEL. ALL OTHER ASPECTS OF THE FORECAST LOOK GOOD. UPDATES AND
NPW HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 351 PM MST WED DEC 17 2014
FOG AND LOW STRATUS LOOKS TO RETURN TONIGHT ACROSS THE PANHANDLE
AND ALSO CENTRAL AND WESTERN PORTIONS OF CARBON COUNTY AS
FORECAST SOUNDINGS SHOW NEARLY SATURATED LLVLS WITH LIGHT SSW
SURFACE WINDS IN PLACE FOR THESE AREAS. UPPER LEVEL WINDS WILL
REMAIN LIGHT AS WELL WITH LITTLE IN THE MEANS OF ANY DISTURBANCES
ALOFT DISRUPTING THE LOWER LEVELS...SO PERSISTENCE FORECAST SEEMS
REASONABLE. LIGHT SNOW WILL CONTINUE OVER THE MOUNTAINS IN THIS
PATTERN AS WELL...WITH GENERALLY LESS THAN AN INCH OF ACCUMULATION
EXPECTED. THINKING THAT THE FOG AND LOW STRATUS WILL NOT STICK
AROUND AS LONG TOMORROW AS TODAY/YESTERDAY AS A SHORTWAVE TROUGH
APPROACHES FROM THE PAC NW AND DEEPENS THE LEESIDE SFC PRESSURE
TROUGH...THUS INCREASING WEST WINDS ACROSS THE CWA AND NUDGING THE
LLVL MOISTURE EASTWARD. THE EXCEPTION COULD BE OUT WEST IN THE
LOWER ELEVATIONS OF CARBON COUNTY WHERE THE WESTERLY WINDS COULD
MAINTAIN INFLUX OF LLVL MOISTURE TO THIS AREA. LIKELY TO SEE WIND
GUSTS OF 30 TO 35 MPH IN THE WIND PRONE AREAS ALONG AND WEST OF
THE LARAMIE RANGE THROUGH THE DAY AS THE PRESSURE GRADIENT
STRENGTHENS IN ADVANCE OF THE UPPER TROUGH...WITH WARMING TEMPS
ACROSS THE EASTERN PLAINS WITH THESE DOWNSLOPE WINDS IN PLACE.
WINDS WILL INCREASE SLIGHTLY FOR THE WIND PRONE AREAS FOR TOMORROW
NIGHT AND FRIDAY AS THE UPPER LEVEL TROUGH MOVES OVERHEAD WITH
GUSTS OF 40 TO 50 MPH POSSIBLE THROUGH EARLY FRIDAY AFTERNOON.
EXPECTING LIGHT SNOW SHOWERS TO CONTINUE THROUGH THIS TIME ALONG
WITH SLIGHTLY WARMER TEMPS ACROSS THE PLAINS.
OTHERWISE...CONDITIONS WILL REMAIN DRY AND BREEZY THROUGH FRIDAY
NIGHT.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 351 PM MST WED DEC 17 2014
RATHER ZONAL FLOW SATURDAY WILL BECOME NWLY SATURDAY NIGHT AND
SUNDAY AS RIDGING AMPLIFIES ALONG THE WEST COAST. MAINLY DRY
OUTSIDE OF THE MTNS WHERE OROGRAPHICS SHOULD ALLOW FOR SOME SNOW
SHOWERS BOTH DAYS. LOOKING RATHER WINDY SAT NIGHT AND SUNDAY AS AN
UPPER JET MOVES INTO THE PACIFIC NW INTO THE NRN ROCKYS AND SFC
PRESSURE FALLS OCCUR OVER THE HIGH PLAINS AHEAD OF SHORTWAVE
ENERGY OVER THE PACIFIC NW. A COOL FRONT SHOULD THEN PASS ACROSS
LATE SUNDAY WITH A DECENT SURGE OF MOISTURE INCREASING SNOW SHOWER
ACTIVITY ESPECIALLY OVER THE SW PART OF THE CWA SUNDAY NIGHT AND
MONDAY. COOL AND SOMEWHAT BREEZY CONDITIONS EXPECTED FOR TUESDAY
AND WEDS AS THE CWA REMAINS UNDER NWLY FLOW ALOFT WITH SNOW
SHOWERS CONTINUING OVER THE HIGHER MTNS AS MOISTURE RIDES UP
FACING SLOPES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 351 PM MST WED DEC 17 2014
VFR EXPECTED OVER SE WY TERMINALS THROUGH THE PERIOD. IFR TO MVFR
CIGS/VSBYS LIKELY TO SPREAD BACK ACROSS MUCH OF NEB PANHANDLE THIS
EVENING DUE TO SNOW COVER AND WEAK UPSLOPE FLOW.
&&
.FIRE WEATHER...
ISSUED AT 351 PM MST WED DEC 17 2014
NO FIRE WEATHER CONCERNS THROUGH FRIDAY. COLD TEMPERATURES
WILL KEEP SNOW COVER ON THE GROUND ACROSS MUCH OF THE REGION.
AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 45 PERCENT AND
WINDS WILL BE WEAK THROUGH THURSDAY. BY THURSDAY NIGHT AND
FRIDAY...WEST WINDS WILL BECOME BREEZY FOR AREAS ALONG AND WEST
OF THE LARAMIE RANGE.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 8 AM MST THURSDAY FOR WYZ108.
NE...DENSE FOG ADVISORY UNTIL 8 AM MST THURSDAY FOR NEZ003-019-021-
096.
&&
$$
UPDATE...CLH
SHORT TERM...RJM
LONG TERM...RE
AVIATION...RE
FIRE WEATHER...RJM
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
400 AM MST THU DEC 18 2014
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 400 AM MST THU DEC 18 2014
A VERY WEAK LOW AMPLITUDE UPPER TROUGH WILL BE MOVING OVER THE
STATE TODAY WITH WEAK WESTERLY WINDS ALOFT AND VERY LITTLE FORCING
FOR ASCENT. MOISTURE LEVELS OVER THE MOUNTAINS WILL BE SUFFICIENT
FOR THE WEAK WEST WINDS TO PRODUCE PERIODS OF LIGHT OROGRAPHIC
SNOWFALL. DO NOT EXPECT TO SEE ANY ACCUMULATIONS GREATER THAN ONE
OF TWO INCHES. AREAS OF FOR AND LOW CLOUDS HAVE BEEN DRIFITNG OVER
THE NORTHEAST CORNER OF THE STATE EARLIER THIS MORNING...BUT
VISIBILITIES AT METAR STATIONS HAVE RECENTLY BEEN IMPROVING. WILL
HANG ON TO THE MENTION OF AREAS OF FOG THROUGH ABOUT MID MORNING.
WILL ALSO HANG ON TO PARTLY AND MOSTLY CLOUDY SKY COVER ACROSS
THE FORECAST AREA DUE TO THE MID-LEVEL MOISTURE THAT WILL BE
ADVECTING ACROSS THE REGION. TEMPERATURES SHOULD BE AROUND NORMAL
FOR THIS TIME OF YEAR IN THE ABSENCE OF ANY STRONG DOWNSLOPING
WARMING OR STRONG SUNSHINE. THE UPPER TROUGH WILL REMAIN OVER THE
FORECAST AREA THROUGH MIDNIGHT TONIGHT...SO THERE IS LITTLE NEED
TO REDUCE POPS OVER THE MOUNTAINS UNTIL THEN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 400 AM MST THU DEC 18 2014
A WK UPPER LEVEL TROUGH WILL MOVE EAST OF THE AREA EARLY ON FRI AS A
FLAT UPPER LVL RIDGE DEVELOPS BY AFTN. OVERALL CROSS-SECTIONS ONLY
SHOW SOME MOISTURE NR MTN TOP SO WILL ONLY MENTION A SLIGHT CHC OF
SHSN OVER THE HIGHER PEAKS WITH DRY CONDITIONS ELSEWHERE. 850-700
MB TEMPS DO NOT CHANGE MUCH ON FRI SO WILL KEEP HIGHS IN THE LOWER
TO MID 40S OVER THE URBAN CORRIDOR BUT KEEP HIGHS IN THE 30S OVER
THE PLAINS WHERE SNOW COVER WILL STILL EXIST.
ON SAT ANOTHER WK UPPER LEVEL TROUGH MAY AFFECT THE AREA BRINGING A
CHC OF -SHSN TO THE MTNS WITH DRY CONDITIONS ELSEWHERE. 850-700 MB
TEMPS RISE A FEW DEGREES SO WILL HAVE HIGHS IN THE LOWER TO MID 40S
OVER NERN CO ALTHOUGH READINGS AROUND DENVER COULD REACH THE UPPER
40S.
BY SUN THE FLOW ALOFT WILL BECOME MORE NWLY AND INTENSIFY. MOISTURE
WILL GRADUALLY INCREASE IN THE MTNS THRU THE DAY SO SHOULD A BETTER
CHC OF SNOW ESPECIALLY BY AFTN. OVER NERN CO IT WILL REMAIN DRY
ALTHOUGH MAY SEE AN INCREASE IN MID AND HIGH LVL CLOUD COVER. 850-
700 MB TEMPS RISE ANOTHER 3 DEGREES OR SO WHICH MAY ALLOW FOR HIGHS
TO REACH THE LOWER 50S AROUND DENVER WITH 40S ACROSS THE PLAINS.
FOR SUN NIGHT INTO MON STG MOIST NWLY FLOW ALOFT WILL BE OVER THE
AREA WITH INCREASING INSTABILITY ACROSS THE AREA AS LAPSE RATES RISE
INTO THE 7-8 C/KM RANGE. WITH FAVORABLE OROGRAPHICS IN PLACE ALONG
WITH PLACEMENT OF UPPER LVL JET MAY SEE A HEAVY SNOW EVENT IN THE
MTNS AND PORTIONS OF HIGHER VALLEYS. OVER NERN CO APPEARS A BORA
TYPE FNT WILL MOVE ACROSS THE AREA LATE SUN NIGHT INTO MON MORNING.
DESPITE NWLY FLOW IN THE LOWER LEVELS PLACEMENT OF UPPER LEVEL JET
AND DECENT LAPSE RATES COULD LEAD TO SOME SHOWER ACTIVITY OVER NERN
CO. THE ECMWF HAS THE BEST CHC OF PCPN LATE SUN NIGHT INTO MON
MORNING WHILE THE GFS HAS THE BEST CHC MON AFTN INTO MON EVENING.
IN ADDITION THE GFS ATTEMPTS TO TURN THE WINDS MORE NNE MON AFTN
INTO MON EVENING WHICH WOULD INCREASE THE CHC OF PCPN FM DENVER
SOUTH ACROSS THE PALMER DIVIDE. MEANWHILE TEMP PROFILES FM THE
ECMWF WOULD FAVOR PCPN MOSTLY AS SNOW WHILE THE GFS KEEPS READINGS
WARMER WITH PCPN FALLING AS RAIN MON AFTN BEFORE CHANGING TO SNOW
MON EVENING. THIS FAR OUT HARD TO SAY HOW THINGS WILL EVOLVE SO
WILL KEEP POPS IN THE 20-30 PERCENT RANGE FOR NOW SINCE TIMING OF
PCPN IS STILL UNCERTAIN.
FOR TUE STG NWLY FLOW ALOFT WILL CONTINUE OVER THE AREA. CROSS-
SECTIONS SHOW SOME DECREASE IN MOISTURE DEPTH IN THE MTNS HOWEVER
LAPSE RATES REMAIN IN THE 7-8 C/KM RANGE. THUS WILL STILL SEE
PERIODS OF OROGRAPHIC DRIVEN SNOW. OVER NERN CO THE ECMWF SHOWS A
WK SURGE OF COOLER AIR MON NIGHT INTO TUE MORNING ALONG THE FRONT
RANGE WHICH COMBINES WITH DECENT LAPSE RATES TO PRODUCE SNOW ALONG
THE URBAN CORRIDOR WHICH IS ENHANCED BY PLACEMENT OF UPPER LEVEL
JET. THE GFS SORT OF SHOWS A SIMILAR SET UP BUT DOES NOT HAVE AS
MUCH PCPN. FOR NOW WILL JUST MENTION A SLIGHT CHC OF SNOW FOR THE
LATE MON NIGHT INTO TUE MORNING TIME PERIOD. AS FOR HIGHS WILL KEEP
HIGHS IN THE 35 TO 40 DEGREE RANGE OVER THE PLAINS.
FOR TUE NIGHT INTO WED THE FLOW ALOFT WILL CONTINUE MAINLY NWLY.
CROSS-SECTIONS SHOW MOISTURE DEPTH INCREASING IN THE MTNS WITH
FAVORABLE LAPSE RATES SO SHOULD CONTINUE TO SEE PERIODS OF
OROGRAPHIC SNOW WHICH MAY BE ENHANCED BY PLACEMENT OF UPPER LEVEL
JET. OVER NERN CO BOTH THE ECMWF AND GFS SHOW ANOTHER SURE OF
COOLER AIR MOVING INTO THE AREA TUE NIGHT INTO EARLY WED. ONCE
AGAIN WITH PLACEMENT OF UPPER LEVEL JET AND FAVORABLE LAPSE RATES
COULD SEE ANOTHER CHC OF SNOW DURING THIS TIME PERIOD. THUS WILL
INCLUDE SOME LOW POPS. HIGHS ON WED SHOULD STAY IN THE 30S OVER
NERN CO BASED ON LATEST 850-700 MB TEMPS.
LOOKING AHEAD TOWARDS CHRISTMAS EVE INTO CHRISTMAS DAY LATEST ECMWF
AND GFS INDICATE A GOOD CHC OF SNOW AS AN UPPER LEVEL TROUGH MOVES
SE INTO THE RGN ALONG WITH ANOTHER SHOT OF COLDER AIR. OF COURSE
THIS IS STILL A WEEK AWAY SO WE SHALL SEE HOW THINGS PLAY OUT.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 400 AM MST THU DEC 18 2014
SURFACE PRESSURE GRADIENTS WILL BE QUITE WEAK ACROSS NORTHEAST
COLORADO THROUGH TODAY AND TONIGHT...SO LIGHT WINDS ARE EXPECTED
TO CONTINUE. THE RAP INDICATES SOME LIGHT EASTERLY WINDS IN THE
AFTERNOON AND EVENING...BUT SPEEDS SHOULD REMAIN IN THE 5-10 KNOT
RANGE. NOTHING MORE THAN MID AND HIGH LEVEL CLOUDS ARE EXPECTED
THROUGH THE NEXT 24 HOURS AS THE WEAK UPPER LEVEL DISTURBANCE
MEANDERS OVERHEAD. IMPACTS TO AVIATION OPERATIONS SHOULD BE
MINIMAL.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DANKERS
LONG TERM...RPK
AVIATION...DANKERS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
957 AM EST THU DEC 18 2014
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 252 AM EST THU DEC 18 2014
HIGH PRESSURE IS EXPECTED ACROSS THE AREA THROUGH THE END OF THE
WEEK. THE NORTHERN FRINGES OF A LOW PRESSURE SYSTEM PASSING THROUGH
THE GULF COAST STATES MAY AFFECT PARTS OF THE AREA BY THE END OF
WEEK. A SIGNIFICANT LOW PRESSURE SYSTEM MAY MOVE INTO THE AREA BY
THE EARLY TO MIDDLE PARTS OF NEXT WEEK.
&&
.NEAR TERM /THIS AFTERNOON/...
ISSUED AT 956 AM EST THU DEC 18 2014
SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWS HIGH PRESSURE IN PLACE
OVER THE UPPER MIDWEST AND THE OHIO VALLEY. RADAR RETURNS SHOW
ECHO ALOFT OVE MUCH OF CENTRAL ILLINOUIS...HOWEVER SURFACE OBS
ONLY REPORT SN FALLING ACROSS WEST CENTRAL ILLINOIS. HRRR TENDS TO
KEEP THE ONGOING PRECIP SOUTH OF CENTRAL INDIANA AND WANES THE
ONGOING PRECIP OVER WESTERN ILLINOIS. ATTM...THE HRRR DOESN/T
APPEAR HANDLE THE ONGOING SITUTAION WELL. GFS 285K ISENTROPIC
SURFACE SHOWS GOOD UPGLIDE ACROSS MISSOURI...HELPING THE ONGOING
SNOW THERE. THIS FEAUTRE HOWEVER DOES NOT TRANSLATE WELL TO
CENTRAL INDIANA AS MODELS SUGGEST THE ISENTROPIC LIFT FAILS TO
REACH INDIANA. TIME HEIGHT SECTIONS CONTINUE TO SUGGEST GOOD MID
AND LOWER LEVEL MOISTURE AVAILABLE BETWEEN 18Z AND 00Z. CONFIDNECE
REMAINS LOW IN THIS EVENT...BUT WILL MONITOR CLOSELY. FOR NOW HAVE
ADDED SLIGHT CHC POPS TO MAINLY THE SOUTHERN PARTS OF THE FORECAST
AREA...WITH FLURRIES ELSEWHERE. WILL BE QUICK TO UPDATE SHOULD
ECHOS OVER ILLINOIS HOLD TOGETHER AND PRECIP BEGINS TO REACH THE
GROUND.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 252 AM EST THU DEC 18 2014
MODEL DATA SUGGEST THERE MAY STILL SOME REMNANT ENERGY MOVING
THROUGH THE AREA THIS EVENING ASSOCIATED WITH TODAY/S
DISTURBANCE...SO WILL EXTEND THE FLURRY MENTION INTO THE EVENING
HOURS TONIGHT.
OTHERWISE...A SPLIT FLOW IS EXPECTED TO DEVELOP BY THE END OF THE
WEEK AS THE UPPER BLOCK OVER SOUTHERN CANADA BREAKS DOWN. A SOUTHERN
STREAM DISTURBANCE IS EXPECTED TO SCOOT ALONG THE GULF COAST
STATES...WHILE A DRIER NORTHERN STREAM SYSTEM DIGS INTO THE GREAT
LAKES BY SATURDAY. OPERATIONAL GUIDANCE IS IN PRETTY GOOD AGREEMENT
IN KEEPING THE MAIN PRECIPITATION THREAT TIED UP IN THE SOUTHERN
STREAM AND WELL SOUTH OF THE LOCAL AREA. THERE ARE SOME ENSEMBLES
THAT DRAW ENOUGH MOISTURE NORTH FOR A THREAT FOR LIGHT SNOW AND
MINOR ACCUMULATIONS OVER THE SOUTHERN/SOUTHEASTERN ZONES LATE FRIDAY
NIGHT INTO SATURDAY. TO COVER THIS POSSIBILITY...WILL KEEP SOME
CHANCE POPS GOING FOR LIGHT SNOW DURING THOSE PERIODS OVER ABOUT THE
SOUTHEAST HALF OF THE FORECAST AREA.
GIVEN THE DEGREE OF CLOUD COVER EXPECTED OVER THE NEXT COUPLE OF
DAYS...WILL CONTINUE TO NARROW THE DIURNAL RANGE OF THE GFS MOS
TEMPERATURE GUIDANCE THROUGH THE PERIOD.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 340 AM EST THU DEC 18 2014
EXTENDED MODELS AND ENSEMBLES AGREE THAT STRONG PACIFIC JET...ARCING
OVER A HIGH AMPLITUDE WEST COAST UPPER RIDGE...WILL DIVE SOUTHEAST
OVER THE CENTRAL UNITED STATES DURING THE EARLY AND MIDDLE PART OF
NEXT WEEK RESULTING IN AN UPPER TROUGH CLOSING INTO AN UPPER LOW AND
INTENSIFYING INTO A VERY STRONG SYSTEM BEFORE IT MOVES INTO
SOUTHEASTERN CANADA ON CHRISTMAS. MODELS WERE NOT TOO FAR OFF
REGARDING STRENGTH AND TIMING OF THIS SYSTEM...SO A BLEND OF THE
FURTHER NORTH 00Z GFS AND FURTHER SOUTH 12Z ECMWF LOOKS GOOD.
00Z MODELS ARE SHOWING AN UPPER TROUGH OVER SOUTHEASTERN SOUTH
DAKOTA OR NORTHWESTERN IOWA AT 00Z TUESDAY WITH BROAD AREA OF UPPER
DIFFLUENT FLOW ALOFT OVER THE OHIO VALLEY AND GREAT LAKES.
MEANWHILE...LOW LEVEL FLOW WILL BE SOUTHERLY BY MONDAY AND OPEN THE
OHIO VALLEY AND GREAT LAKES TO THE GULF RESULTING IN DEEPENING
MOISTURE TO GO ALONG WITH THE UPPER FORCING. THIS WILL BRING RAIN TO
THE AREA BY MONDAY AS WELL AS ABOVE NORMAL TEMPERATURES. THE WARMER
TEMPERATURES AND RAIN WILL BE SHORT-LIVED...HOWEVER AS COLDER AIR
RUSHES IN FROM THE NORTHWEST ON THE BACK END OF THE SYSTEM LATE
TUESDAY OR TUESDAY NIGHT. ALONG WITH THE COLDER AIR...UPPER IMPULSES
WILL MOVE ACROSS THE AREA IN THE CYCLONIC FLOW IN THE WAKE OF THE
DEPARTING STACKED LOW THAT SHOULD MOVE INTO QUEBEC EARLY CHRISTMAS.
THIS SHOULD GENERATE SOME SNOW WITH LIGHT ACCUMULATION POSSIBLE BY
CHRISTMAS EVE.
00Z GFS ENSEMBLE MOS TEMPERATURES LOOK TOO WARM THIS WEEKEND.
STRONGLY PREFER THE COOLER 00Z DECEMBER 17 EUROPEAN ENSEMBLE MEAN
TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 18/1500Z TAF UPDATE/...
ISSUED AT 907 AM EST THU DEC 18 2014
UPDATE...
NO FLIGHT CATEGORY CHANGES.
PREVIOUS DISCUSSION...
GOOD CONFIDENCE THAT CLOUDS WILL CONTINUE TO BLANKET THE
TERMINALS THROUGH THE TAF PERIOD. THINK CONDITIONS WILL MOSTLY BE
VFR...ALTHOUGH WOULD NOT RULE OUT SOME MVFR AT TIMES.
WINDS WILL BE 5 KNOTS OR LESS THROUGHOUT UNDER SURFACE HIGH
PRESSURE.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JAS
NEAR TERM...PUMA
SHORT TERM...JAS
LONG TERM...MK
AVIATION...MK/TDUD
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AREA FORECAST DISCUSSION
NWS GOODLAND KS
555 AM MST THU DEC 18 2014
.UPDATE...
ISSUED AT 554 AM MST THU DEC 18 2014
EARLIER UPDATE WAS TO ISSUE DENSE FOG ADVISORY FOR OUR CWA. DENSE
FOG DEVELOPED FROM OAKLEY TO TRIBUNE TO BURLINGTON...BUT HAS BEEN
A BIT MORE VARIABLE ALONG THE KS/CO BORDER. SHORT RANGE GUIDANCE
GENERALLY FAVORS THE WESTERN PART OF THE CWA...THOUGH RAP DOES
SHOW THE PATCH OF FOG NEAR OAKLEY SPREADING A LITTLE BIT MORE TO
THE NORTH AND EAST TOWARD GRAHAM COUNTY. I AM NOT AS SURE ABOUT
HRRR WHICH ACTUALLY SHOWED FOG EXPANDING FROM THE COLORADO BORDER
TO THE EAST AND LINGERING THROUGH THE AFTERNOON. HIGHER SURFACE TD
VALUES ARE IN OUR EAST AND LIGHT FOG IS IN PLACE. I WOULD NOT BE
SURPRISED IF DENSE FOG COVERAGE INCREASED AND SPREAD EAST AROUND
OR AFTER SUNRISE...SO I DECIDED TO COVER THE ENTIRE AREA FOR THE
ADVISORY.
WHILE CURRENT DENSE FOG COVERAGE IS SOMEWHAT PATCHY...ROAD
CONDITIONS AFTER YESTERDAYS FREEZING DRIZZLE AND LAST NIGHTS LIGHT
SNOW ARE IN POOR CONDITION ACROSS MANY LOCATIONS. EVEN PATCHY
DENSE FOG WITH THESE ROAD CONDITIONS WOULD MAKE TRAVEL DANGEROUS.
I FELT MORE COMFORTABLE WITH A DENSE FOG ADVISORY THAN SPS DESPITE
THE VARIABLE NATURE OF THE CONDITIONS SO FAR THIS MORNING.
UPDATE ISSUED AT 412 AM MST THU DEC 18 2014
UPDATE TO CANCEL WINTER WEATHER ADVISORY. SNOW BAND HAS FALLEN
APART AND FREEZING DRIZZLE HAS COME TO AN END. UPPER LOW IS NOW
OVER NORTHEAST KS/SOUTHEAST NE. WHILE GOOD LOW LEVEL MOISTURE IS
SUPPORTING DENSE FOG REDEVELOPMENT...BETTER MOISTURE ADVECTION
WILL REMAIN EAST OF THE CWA THROUGH THE REST OF THE MORNING...SO
FREEZING DRIZZLE THREAT IS MINIMAL. I CANT JUSTIFY A WINTER
WEATHER ADVISORY JUST FOR FREEZING FOG...BUT FELT THE NEED TO KEEP
A SPS OUT TO COVER FREEZING FOG POTENTIAL. WILL MONITOR OVER THE
NEXT HOUR AND IF FOG CONTINUES TO INCREASE IN COVERAGE I MAY NEED
TO ISSUE DENSE FOG ADVISORY FOR THE MORNING HOURS.
&&
.SHORT TERM...(THIS MORNING THROUGH SATURDAY NIGHT)
ISSUED AT 244 AM MST THU DEC 18 2014
EARLY MORNING WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW SHORTWAVE
TROUGH OVER NORTHCENTRAL KANSAS WITH AREA OF SUBSIDENCE ALONG
SHORTWAVE RIDGE AXIS BUILDING INTO THE NEBRASKA PANHANDLE. AT THE
SURFACE A STATIONARY FRONT REMAINS IN PLACE OVER EASTERN COLORADO
WITH SOUTH TO SOUTHEAST FLOW IN PLACE ACROSS OUR CWA.
REGARDING WINTER WEATHER ADVISORY EARLY THIS MORNING....
RADAR AND SURROUNDING OBS SHOW A BAND OF LIGHT SNOW THAT FORMED ON
BACK SIDE OF H7 LOW MOVING EAST OVER OUR EASTERN CWA. THIS SNOW HAS
HELPED MIX OUT THE LOW LEVELS OF THE ATMOSPHERE WITH SHIFT IN LOW
LEVEL FLOW TO THE NORTHWEST AIDING IMPROVEMENT IN CONDITIONS
ACROSS THE WESTERN FORECAST AREA. BASED ON SHORT RANGE MODELS...I
AM STILL CONCERNED THAT LIGHT WINDS AND SHALLOW LOW LEVEL MOISTURE
COULD LEAD TO FREEZING FOG REDEVELOPMENT BEHIND THIS SNOW BAND.
FREEZING FOG/DRIZZLE WILL REMAIN POSSIBLE AHEAD OF IT WITH BETTER
MOISTURE ADVECTION/POOLING. OVERALL TREND THROUGH THE MORNING
SHOULD BE IMPROVEMENT IN CONDITIONS AROUND 12-15Z...WITH ANY FOG
CLEARING BY MIDDAY. AFTER 12Z I AM SKEPTICAL THAT FLOW WOULD ALLOW
FOR ENOUGH ADDITIONAL MOISTURE ADVECTION TO SUPPORT CONTINUED
FREEZING DRIZZLE...THOUGH FOG COULD BE POSSIBLE THROUGH MOST OF
THE MORNING ESPECIALLY IN THE EAST WHERE SOUTHERLY FLOW MAY LINGER
A LITTLE LONGER. WITH THIS IN MIND I PLAN ON HOLDING ONTO CURRENT
WINTER WEATHER ADVISORY THROUGH EXPIRATION IN CASE I NEED TO
EXTEND IT IN TIME FOR EASTERN LOCATIONS THROUGH 15Z.
REST OF TODAY...SHORTWAVE RIDGING WILL CONTINUE TO BUILD EAST
TODAY AND AIR MASS WILL BEING MODERATING AND DRYING AS SURFACE
TROUGH SHIFTS EAST. THERE MAYBE DECENT CLEARING WHICH COULD
SUPPORT TEMPS IN THE LOWER 40S (FOR LOCATIONS WITHOUT SNOW PACK).
IT IS TOUGH TO SAY HOW MUCH CLEARING AS MODELS HOLD ONTO STRATUS
OVER PARTS OF THE AREA INTO THE AFTERNOON. NOT A LOT OF
CONFIDENCE IN TEMPS...SO MADE MINOR ADJUSTMENT TO TODAYS HIGHS.
TONIGHT-SATURDAY NIGHT...A SHORTWAVE TROUGH WILL PASS THROUGH THE
SOUTHERN PLAINS THROUGH FRIDAY MORNING...WITH MINIMAL IMPACT ON
SENSIBLE WEATHER OVER OUR CWA. NAM AND SREF BL RH CONTINUE TO RUN
HIGH...LIKELY AS A RESULT OF SNOW PACK...AND SUPPORT FOG/STRATUS
DURING THE OVERNIGHT PERIODS. I ADDED PATCHY FOG TO TONIGHT AS
WINDS WILL BE LIGHT AND THERE COULD BE SOME LINGERING BL MOISTURE
POOLING ALONG AND EAST OF SURFACE TROUGH...THOUGH CONFIDENCE IS
PRETTY LOW AS TROUGH MAY BE EAST OF OUR CWA. THOUGH TEMPS WILL BE
SUBFREEZING...CONFIDENCE IS TOO LOW THAT ANY FOG WOULD BE DENSE
ENOUGH TO WORRY ABOUT ICE ACCUMULATION (FREEZING FOG). I AM
LEAVING FOG OUT OF FRIDAY NIGHT AND SATURDAY NIGHT TO SEE HOW
THINGS EVOLVE TONIGHT FIRST. SHORTWAVE RIDGE SHOULD BUILD BACK
OVER THE PLAINS FRIDAY THROUGH SATURDAY...WITH CONTINUED
MODERATION OF THE AIR MASS ALOFT. COMPLICATION TO TEMP FORECAST
WILL CONTINUE TO BE IMPACT OF DEEPER SNOW PACK IN OUR NORTHWEST
CWA.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 244 AM MST THU DEC 18 2014
THE LONG TERM PERIOD WILL START OUT WITH SLIGHTLY ABOVE AVERAGE
TEMPERATURES ON SUNDAY WITH WARM SOUTHERLY WINDS KEEPING
TEMPERATURES IN THE MID TO UPPER 40S. THE NEXT WEATHER MAKING
SYSTEM WILL APPROACH THE HIGH PLAINS REGION AS AN UPPER LEVEL TROUGH
AND SURFACE LOW PRESSURE SYSTEM MOVE ACROSS THE NORTHERN PLAINS.
THIS SYSTEM WILL BRING IN COLDER AIR TO THE PLAINS WITH CHANCES FOR
PRECIPITATION STARTING EARLY MONDAY MORNING...MOSTLY FOR EASTERN
COLORADO LOCATIONS.
PRECIPITATION MONDAY WILL BEGIN AS SNOW IN THE MORNING WITH COOLER
TEMPERATURES AT THE LOWER LEVELS...BUT WILL BECOME RAIN IN THE
AFTERNOON WITH HIGH TEMPERATURES REACHING THE MID 40S TO LOWER 50S.
AFTER SUNSET...PRECIPITATION WILL TRANSITION BACK TO SNOW THROUGH
THE OVERNIGHT HOURS. UNDER AN INCH OF SNOW IS POSSIBLE WITH THIS
SYSTEM.
THE UPPER LEVEL LOW IS DEPICTED IN GUIDANCE AS STALLING OVER THE
UPPER MIDWEST STATES...BUT THE TRI STATE AREA WILL BE UNDER THE
INFLUENCE OF STRONG NORTHWEST FLOW TUESDAY AS AN UPPER LEVEL RIDGE
BUILDS IN THE WEST. THE HIGHER AMPLITUDE RIDGE WILL BREAK DOWN AND
MOVE WESTWARD TO BRING A SHORTWAVE RIDGE OF HIGH PRESSURE OVER THE
CENTRAL PLAINS TO BRING DRY CONDITIONS AND NEAR AVERAGE TEMPERATURES
FOR TUESDAY AND WEDNESDAY. HIGH TEMPERATURES WILL RANGE FROM THE
UPPER 30S TO MID 40S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 439 AM MST THU DEC 18 2014
LINGER LOW LEVEL MOISTURE HAS SUPPORTED FREEZING FOG REDEVELOPMENT
ACROSS NW KANSAS WHICH IS SPREADING INTO EASTERN COLORADO AND
SOUTHWEST NEBRASKA. VLIFR CONDITIONS ARE ALREADY IN PLACE AT
KGLD...AND CONDITIONS SHOULD DETERIORATE AT KMCK OVER THE NEXT
HOUR. VLIFR CONDITIONS SHOULD EVENTUALLY TRANSITION TO MVFR AND
THEN VFR BY LATE MORNING AS MAIN MOISTURE AXIS SHIFTS EAST. THERE
IS A POSSIBILITY THAT LOW STRATUS MAY LINGER THROUGH THE AFTERNOON
AND FOG/STRATUS POSSIBLY REDEVELOP LATER TONIGHT. HOWEVER...MODEL
DATA MAY BE OVERLY INFLUENCED BY LINGERING SNOW PACK...SO I KEPT
CONDITIONS VFR AFTER MIDDAY FOR BOTH TAFS. WINDS SHOULD REMAIN
LIGHT AROUND 5KT OR LESS THROUGH THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...DENSE FOG ADVISORY UNTIL 9 AM MST /10 AM CST/ THIS MORNING FOR
KSZ001>004-013>016-027>029-041-042.
CO...DENSE FOG ADVISORY UNTIL 9 AM MST THIS MORNING FOR COZ090>092.
NE...DENSE FOG ADVISORY UNTIL 9 AM MST /10 AM CST/ THIS MORNING FOR
NEZ079>081.
&&
$$
UPDATE...DR
SHORT TERM...DR
LONG TERM...MK
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
439 AM MST THU DEC 18 2014
.UPDATE...
ISSUED AT 412 AM MST THU DEC 18 2014
UPDATE TO CANCEL WINTER WEATHER ADVISORY. SNOW BAND HAS FALLEN
APART AND FREEZING DRIZZLE HAS COME TO AN END. UPPER LOW IS NOW
OVER NORTHEAST KS/SOUTHEAST NE. WHILE GOOD LOW LEVEL MOISTURE IS
SUPPORTING DENSE FOG REDEVELOPMENT...BETTER MOISTURE ADVECTION
WILL REMAIN EAST OF THE CWA THROUGH THE REST OF THE MORNING...SO
FREEZING DRIZZLE THREAT IS MINIMAL. I CANT JUSTIFY A WINTER
WEATHER ADVISORY JUST FOR FREEZING FOG...BUT FELT THE NEED TO KEEP
A SPS OUT TO COVER FREEZING FOG POTENTIAL. WILL MONITOR OVER THE
NEXT HOUR AND IF FOG CONTINUES TO INCREASE IN COVERAGE I MAY NEED
TO ISSUE DENSE FOG ADVISORY FOR THE MORNING HOURS.
&&
.SHORT TERM...(THIS MORNING THROUGH SATURDAY NIGHT)
ISSUED AT 244 AM MST THU DEC 18 2014
EARLY MORNING WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW SHORTWAVE
TROUGH OVER NORTHCENTRAL KANSAS WITH AREA OF SUBSIDENCE ALONG
SHORTWAVE RIDGE AXIS BUILDING INTO THE NEBRASKA PANHANDLE. AT THE
SURFACE A STATIONARY FRONT REMAINS IN PLACE OVER EASTERN COLORADO
WITH SOUTH TO SOUTHEAST FLOW IN PLACE ACROSS OUR CWA.
REGARDING WINTER WEATHER ADVISORY EARLY THIS MORNING....
RADAR AND SURROUNDING OBS SHOW A BAND OF LIGHT SNOW THAT FORMED ON
BACK SIDE OF H7 LOW MOVING EAST OVER OUR EASTERN CWA. THIS SNOW HAS
HELPED MIX OUT THE LOW LEVELS OF THE ATMOSPHERE WITH SHIFT IN LOW
LEVEL FLOW TO THE NORTHWEST AIDING IMPROVEMENT IN CONDITIONS
ACROSS THE WESTERN FORECAST AREA. BASED ON SHORT RANGE MODELS...I
AM STILL CONCERNED THAT LIGHT WINDS AND SHALLOW LOW LEVEL MOISTURE
COULD LEAD TO FREEZING FOG REDEVELOPMENT BEHIND THIS SNOW BAND.
FREEZING FOG/DRIZZLE WILL REMAIN POSSIBLE AHEAD OF IT WITH BETTER
MOISTURE ADVECTION/POOLING. OVERALL TREND THROUGH THE MORNING
SHOULD BE IMPROVEMENT IN CONDITIONS AROUND 12-15Z...WITH ANY FOG
CLEARING BY MIDDAY. AFTER 12Z I AM SKEPTICAL THAT FLOW WOULD ALLOW
FOR ENOUGH ADDITIONAL MOISTURE ADVECTION TO SUPPORT CONTINUED
FREEZING DRIZZLE...THOUGH FOG COULD BE POSSIBLE THROUGH MOST OF
THE MORNING ESPECIALLY IN THE EAST WHERE SOUTHERLY FLOW MAY LINGER
A LITTLE LONGER. WITH THIS IN MIND I PLAN ON HOLDING ONTO CURRENT
WINTER WEATHER ADVISORY THROUGH EXPIRATION IN CASE I NEED TO
EXTEND IT IN TIME FOR EASTERN LOCATIONS THROUGH 15Z.
REST OF TODAY...SHORTWAVE RIDGING WILL CONTINUE TO BUILD EAST
TODAY AND AIR MASS WILL BEING MODERATING AND DRYING AS SURFACE
TROUGH SHIFTS EAST. THERE MAYBE DECENT CLEARING WHICH COULD
SUPPORT TEMPS IN THE LOWER 40S (FOR LOCATIONS WITHOUT SNOW PACK).
IT IS TOUGH TO SAY HOW MUCH CLEARING AS MODELS HOLD ONTO STRATUS
OVER PARTS OF THE AREA INTO THE AFTERNOON. NOT A LOT OF
CONFIDENCE IN TEMPS...SO MADE MINOR ADJUSTMENT TO TODAYS HIGHS.
TONIGHT-SATURDAY NIGHT...A SHORTWAVE TROUGH WILL PASS THROUGH THE
SOUTHERN PLAINS THROUGH FRIDAY MORNING...WITH MINIMAL IMPACT ON
SENSIBLE WEATHER OVER OUR CWA. NAM AND SREF BL RH CONTINUE TO RUN
HIGH...LIKELY AS A RESULT OF SNOW PACK...AND SUPPORT FOG/STRATUS
DURING THE OVERNIGHT PERIODS. I ADDED PATCHY FOG TO TONIGHT AS
WINDS WILL BE LIGHT AND THERE COULD BE SOME LINGERING BL MOISTURE
POOLING ALONG AND EAST OF SURFACE TROUGH...THOUGH CONFIDENCE IS
PRETTY LOW AS TROUGH MAY BE EAST OF OUR CWA. THOUGH TEMPS WILL BE
SUBFREEZING...CONFIDENCE IS TOO LOW THAT ANY FOG WOULD BE DENSE
ENOUGH TO WORRY ABOUT ICE ACCUMULATION (FREEZING FOG). I AM
LEAVING FOG OUT OF FRIDAY NIGHT AND SATURDAY NIGHT TO SEE HOW
THINGS EVOLVE TONIGHT FIRST. SHORTWAVE RIDGE SHOULD BUILD BACK
OVER THE PLAINS FRIDAY THROUGH SATURDAY...WITH CONTINUED
MODERATION OF THE AIR MASS ALOFT. COMPLICATION TO TEMP FORECAST
WILL CONTINUE TO BE IMPACT OF DEEPER SNOW PACK IN OUR NORTHWEST
CWA.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 244 AM MST THU DEC 18 2014
THE LONG TERM PERIOD WILL START OUT WITH SLIGHTLY ABOVE AVERAGE
TEMPERATURES ON SUNDAY WITH WARM SOUTHERLY WINDS KEEPING
TEMPERATURES IN THE MID TO UPPER 40S. THE NEXT WEATHER MAKING
SYSTEM WILL APPROACH THE HIGH PLAINS REGION AS AN UPPER LEVEL TROUGH
AND SURFACE LOW PRESSURE SYSTEM MOVE ACROSS THE NORTHERN PLAINS.
THIS SYSTEM WILL BRING IN COLDER AIR TO THE PLAINS WITH CHANCES FOR
PRECIPITATION STARTING EARLY MONDAY MORNING...MOSTLY FOR EASTERN
COLORADO LOCATIONS.
PRECIPITATION MONDAY WILL BEGIN AS SNOW IN THE MORNING WITH COOLER
TEMPERATURES AT THE LOWER LEVELS...BUT WILL BECOME RAIN IN THE
AFTERNOON WITH HIGH TEMPERATURES REACHING THE MID 40S TO LOWER 50S.
AFTER SUNSET...PRECIPITATION WILL TRANSITION BACK TO SNOW THROUGH
THE OVERNIGHT HOURS. UNDER AN INCH OF SNOW IS POSSIBLE WITH THIS
SYSTEM.
THE UPPER LEVEL LOW IS DEPICTED IN GUIDANCE AS STALLING OVER THE
UPPER MIDWEST STATES...BUT THE TRI STATE AREA WILL BE UNDER THE
INFLUENCE OF STRONG NORTHWEST FLOW TUESDAY AS AN UPPER LEVEL RIDGE
BUILDS IN THE WEST. THE HIGHER AMPLITUDE RIDGE WILL BREAK DOWN AND
MOVE WESTWARD TO BRING A SHORTWAVE RIDGE OF HIGH PRESSURE OVER THE
CENTRAL PLAINS TO BRING DRY CONDITIONS AND NEAR AVERAGE TEMPERATURES
FOR TUESDAY AND WEDNESDAY. HIGH TEMPERATURES WILL RANGE FROM THE
UPPER 30S TO MID 40S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 439 AM MST THU DEC 18 2014
LINGER LOW LEVEL MOISTURE HAS SUPPORTED FREEZING FOG REDEVELOPMENT
ACROSS NW KANSAS WHICH IS SPREADING INTO EASTERN COLORADO AND
SOUTHWEST NEBRASKA. VLIFR CONDITIONS ARE ALREADY IN PLACE AT
KGLD...AND CONDITIONS SHOULD DETERIORATE AT KMCK OVER THE NEXT
HOUR. VLIFR CONDITIONS SHOULD EVENTUALLY TRANSITION TO MVFR AND
THEN VFR BY LATE MORNING AS MAIN MOISTURE AXIS SHIFTS EAST. THERE
IS A POSSIBILITY THAT LOW STRATUS MAY LINGER THROUGH THE AFTERNOON
AND FOG/STRATUS POSSIBLY REDEVELOP LATER TONIGHT. HOWEVER...MODEL
DATA MAY BE OVERLY INFLUENCED BY LINGERING SNOW PACK...SO I KEPT
CONDITIONS VFR AFTER MIDDAY FOR BOTH TAFS. WINDS SHOULD REMAIN
LIGHT AROUND 5KT OR LESS THROUGH THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...DR
SHORT TERM...DR
LONG TERM...MK
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
413 AM MST THU DEC 18 2014
.UPDATE...
ISSUED AT 412 AM MST THU DEC 18 2014
UPDATE TO CANCEL WINTER WEATHER ADVISORY. SNOW BAND HAS FALLEN
APART AND FREEZING DRIZZLE HAS COME TO AN END. UPPER LOW IS NOW
OVER NORTHEAST KS/SOUTHEAST NE. WHILE GOOD LOW LEVEL MOISTURE IS
SUPPORTING DENSE FOG REDEVELOPMENT...BETTER MOISTURE ADVECTION
WILL REMAIN EAST OF THE CWA THROUGH THE REST OF THE MORNING...SO
FREEZING DRIZZLE THREAT IS MINIMAL. I CANT JUSTIFY A WINTER
WEATHER ADVISORY JUST FOR FREEZING FOG...BUT FELT THE NEED TO KEEP
A SPS OUT TO COVER FREEZING FOG POTENTIAL. WILL MONITOR OVER THE
NEXT HOUR AND IF FOG CONTINUES TO INCREASE IN COVERAGE I MAY NEED
TO ISSUE DENSE FOG ADVISORY FOR THE MORNING HOURS.
&&
.SHORT TERM...(THIS MORNING THROUGH SATURDAY NIGHT)
ISSUED AT 244 AM MST THU DEC 18 2014
EARLY MORNING WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW SHORTWAVE
TROUGH OVER NORTHCENTRAL KANSAS WITH AREA OF SUBSIDENCE ALONG
SHORTWAVE RIDGE AXIS BUILDING INTO THE NEBRASKA PANHANDLE. AT THE
SURFACE A STATIONARY FRONT REMAINS IN PLACE OVER EASTERN COLORADO
WITH SOUTH TO SOUTHEAST FLOW IN PLACE ACROSS OUR CWA.
REGARDING WINTER WEATHER ADVISORY EARLY THIS MORNING....
RADAR AND SURROUNDING OBS SHOW A BAND OF LIGHT SNOW THAT FORMED ON
BACK SIDE OF H7 LOW MOVING EAST OVER OUR EASTERN CWA. THIS SNOW HAS
HELPED MIX OUT THE LOW LEVELS OF THE ATMOSPHERE WITH SHIFT IN LOW
LEVEL FLOW TO THE NORTHWEST AIDING IMPROVEMENT IN CONDITIONS
ACROSS THE WESTERN FORECAST AREA. BASED ON SHORT RANGE MODELS...I
AM STILL CONCERNED THAT LIGHT WINDS AND SHALLOW LOW LEVEL MOISTURE
COULD LEAD TO FREEZING FOG REDEVELOPMENT BEHIND THIS SNOW BAND.
FREEZING FOG/DRIZZLE WILL REMAIN POSSIBLE AHEAD OF IT WITH BETTER
MOISTURE ADVECTION/POOLING. OVERALL TREND THROUGH THE MORNING
SHOULD BE IMPROVEMENT IN CONDITIONS AROUND 12-15Z...WITH ANY FOG
CLEARING BY MIDDAY. AFTER 12Z I AM SKEPTICAL THAT FLOW WOULD ALLOW
FOR ENOUGH ADDITIONAL MOISTURE ADVECTION TO SUPPORT CONTINUED
FREEZING DRIZZLE...THOUGH FOG COULD BE POSSIBLE THROUGH MOST OF
THE MORNING ESPECIALLY IN THE EAST WHERE SOUTHERLY FLOW MAY LINGER
A LITTLE LONGER. WITH THIS IN MIND I PLAN ON HOLDING ONTO CURRENT
WINTER WEATHER ADVISORY THROUGH EXPIRATION IN CASE I NEED TO
EXTEND IT IN TIME FOR EASTERN LOCATIONS THROUGH 15Z.
REST OF TODAY...SHORTWAVE RIDGING WILL CONTINUE TO BUILD EAST
TODAY AND AIR MASS WILL BEING MODERATING AND DRYING AS SURFACE
TROUGH SHIFTS EAST. THERE MAYBE DECENT CLEARING WHICH COULD
SUPPORT TEMPS IN THE LOWER 40S (FOR LOCATIONS WITHOUT SNOW PACK).
IT IS TOUGH TO SAY HOW MUCH CLEARING AS MODELS HOLD ONTO STRATUS
OVER PARTS OF THE AREA INTO THE AFTERNOON. NOT A LOT OF
CONFIDENCE IN TEMPS...SO MADE MINOR ADJUSTMENT TO TODAYS HIGHS.
TONIGHT-SATURDAY NIGHT...A SHORTWAVE TROUGH WILL PASS THROUGH THE
SOUTHERN PLAINS THROUGH FRIDAY MORNING...WITH MINIMAL IMPACT ON
SENSIBLE WEATHER OVER OUR CWA. NAM AND SREF BL RH CONTINUE TO RUN
HIGH...LIKELY AS A RESULT OF SNOW PACK...AND SUPPORT FOG/STRATUS
DURING THE OVERNIGHT PERIODS. I ADDED PATCHY FOG TO TONIGHT AS
WINDS WILL BE LIGHT AND THERE COULD BE SOME LINGERING BL MOISTURE
POOLING ALONG AND EAST OF SURFACE TROUGH...THOUGH CONFIDENCE IS
PRETTY LOW AS TROUGH MAY BE EAST OF OUR CWA. THOUGH TEMPS WILL BE
SUBFREEZING...CONFIDENCE IS TOO LOW THAT ANY FOG WOULD BE DENSE
ENOUGH TO WORRY ABOUT ICE ACCUMULATION (FREEZING FOG). I AM
LEAVING FOG OUT OF FRIDAY NIGHT AND SATURDAY NIGHT TO SEE HOW
THINGS EVOLVE TONIGHT FIRST. SHORTWAVE RIDGE SHOULD BUILD BACK
OVER THE PLAINS FRIDAY THROUGH SATURDAY...WITH CONTINUED
MODERATION OF THE AIR MASS ALOFT. COMPLICATION TO TEMP FORECAST
WILL CONTINUE TO BE IMPACT OF DEEPER SNOW PACK IN OUR NORTHWEST
CWA.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 244 AM MST THU DEC 18 2014
THE LONG TERM PERIOD WILL START OUT WITH SLIGHTLY ABOVE AVERAGE
TEMPERATURES ON SUNDAY WITH WARM SOUTHERLY WINDS KEEPING
TEMPERATURES IN THE MID TO UPPER 40S. THE NEXT WEATHER MAKING
SYSTEM WILL APPROACH THE HIGH PLAINS REGION AS AN UPPER LEVEL TROUGH
AND SURFACE LOW PRESSURE SYSTEM MOVE ACROSS THE NORTHERN PLAINS.
THIS SYSTEM WILL BRING IN COLDER AIR TO THE PLAINS WITH CHANCES FOR
PRECIPITATION STARTING EARLY MONDAY MORNING...MOSTLY FOR EASTERN
COLORADO LOCATIONS.
PRECIPITATION MONDAY WILL BEGIN AS SNOW IN THE MORNING WITH COOLER
TEMPERATURES AT THE LOWER LEVELS...BUT WILL BECOME RAIN IN THE
AFTERNOON WITH HIGH TEMPERATURES REACHING THE MID 40S TO LOWER 50S.
AFTER SUNSET...PRECIPITATION WILL TRANSITION BACK TO SNOW THROUGH
THE OVERNIGHT HOURS. UNDER AN INCH OF SNOW IS POSSIBLE WITH THIS
SYSTEM.
THE UPPER LEVEL LOW IS DEPICTED IN GUIDANCE AS STALLING OVER THE
UPPER MIDWEST STATES...BUT THE TRI STATE AREA WILL BE UNDER THE
INFLUENCE OF STRONG NORTHWEST FLOW TUESDAY AS AN UPPER LEVEL RIDGE
BUILDS IN THE WEST. THE HIGHER AMPLITUDE RIDGE WILL BREAK DOWN AND
MOVE WESTWARD TO BRING A SHORTWAVE RIDGE OF HIGH PRESSURE OVER THE
CENTRAL PLAINS TO BRING DRY CONDITIONS AND NEAR AVERAGE TEMPERATURES
FOR TUESDAY AND WEDNESDAY. HIGH TEMPERATURES WILL RANGE FROM THE
UPPER 30S TO MID 40S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1033 PM MST WED DEC 17 2014
FOR BOTH TAF SITES FROM 06Z-15Z THURSDAY...MAINLY LIFR/VLIFR
CONDITIONS WITH BRIEF IFR/MVFR MIX THRU 09Z. CEILINGS MAINLY 1/4SM
TO 1/2SM IN A SNOW/FREEZING FOG MIX...WITH PERIODS 1-3SM THRU 09Z.
FROM 15Z ONWARD...IFR CONDITIONS TREND TO VFR BY 00Z FRIDAY.
CEILINGS WILL RANGE FROM BKN-OVC006-010 UP TO BKN100 BY 00Z
FRIDAY. 3-6SM IN FOG DURING THIS TIME...ESPECIALLY BEFORE 00Z
FRIDAY. WINDS MAINLY VARIABLE THRU 15Z...THEN WSW 5-10KTS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...DR
SHORT TERM...DR
LONG TERM...MK
AVIATION...JN
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1025 AM EST THU DEC 18 2014
.UPDATE...
ISSUED AT 1025 AM EST THU DEC 18 2014
14Z SFC ANALYSIS SHOWS A VERY WEAK AREA OF LOW PRESSURE SLIDING BY TO
THE SOUTH OF EASTERN KENTUCKY. THE PRECIPITATION WITH THIS...MAINLY
FLURRIES...IS FADING FAST WITH MOSTLY VIRGA LEFT. TEMPERATURES ARE
GENERALLY IN IN THE UPPER 20S AND LOWER 30S THROUGH THE AREA WITH
DEWPOINTS IN THE MID AND UPPER 20S...WHILE WINDS ARE LIGHT. SATELLITE
SHOWS A FEW BREAKS OUT THERE BUT CIGS ARE MAINLY IN THE LOW MVFR
RANGE NORTH AND VFR SOUTH. HAVE UPDATED THE FORECAST TO DIMINISH THE
POPS QUICKLY THROUGH MIDDAY IN CONJUNCTION WITH THE 12Z NAM12 AND
LATEST HRRR. ALSO FINE TUNED HIGH TEMPERATURES AND THE HOURLY T/TD
GRIDS PER THE LATEST OBS...TRENDS...AND CONSSHORT GUIDANCE. THESE
HAVE BEEN SENT TO THE NDFD AND WEB SERVERS ALONG WITH AN UPDATE TO
THE HWO AND ZONES.
UPDATE ISSUED AT 552 AM EST THU DEC 18 2014
THERE IS A FAIR AMOUNT OF RADAR RETURNS MAKING IT INTO SOUTHEAST
KY...UNLIKE WHAT MANY OF THE HI RES MODELS WERE SHOWING EARLIER.
DESPITE THE DRY AIR IN PLACE AT THE SURFACE...DEW POINT DEPRESSIONS
HAVE LESSENED TO 0 IN SOME OF OUR SOUTHWESTERN COUNTIES. AND WITH
SNOW AND SLEET BEING REPORTED ONLY A FEW COUNTIES OVER...DECIDED IT
WAS TIME TO GO AHEAD AND EXPAND THE CHANCES FOR PRECIP THIS MORNING.
AS IT IS NOW...IT LOOKS LIKE ALL OF THE COUNTIES ALONG THE TENNESSEE
BORDER...AS WELL AS THE NEXT TIER OF COUNTIES NORTHWARD WILL LIKELY
BE AFFECTED BY LIGHT SNOW AND POTENTIAL SLEET THIS MORNING. LATEST HI
RES MODELS...INCLUDING THE HRRR AND NAM 12 ARE SHOWING THE SYSTEM
LOSING INTENSITY VERY QUICKLY THIS MORNING...AND CUTTING OFF PRECIP
CHANCES ACROSS OUR CWA WITHIN THE NEXT FEW HOURS. HOWEVER...GIVEN THE
LEVEL OF UNCERTAINTY...AND THE ONGOING STRONG REFLECTIVITIES...ERRED
ON THE PESSIMISTIC SIDE AND KEPT MENTION OF SNOW AND ICE IN UNTIL MID
MORNING. ALSO...WENT AHEAD AND ISSUED A SPECIAL WEATHER STATEMENT
THROUGH 15Z FOR THE AFFECTED COUNTIES SINCE ANY PRECIP WILL LIKELY
ACCUMULATE ON SURFACES DURING THE MORNING COMMUTE.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 358 AM EST THU DEC 18 2014
SURFACE HIGH PRESSURE CONTINUES TO BE IN CHARGE FOR THE OHIO RIVER
VALLEY AND MANY POINTS TO OUR NORTH AND SOUTH. STRONG SUBSIDENCE
TRAPPING LOW LEVEL MOISTURE ACROSS THE NE PORTION OF THE CWA HAS LED
TO CONTINUED MVFR CLOUDS...WHICH ACCORDING TO THE LATEST FORECAST
SOUNDINGS...SHOULDN/T BE BUDGING UNTIL SOMETIME EARLY THIS
AFTERNOON. MEANWHILE...ALOFT...A SHORTWAVE IS CONTINUING TO DAMPEN
AS IT TRACKS EASTWARD...AND SHOULD BE POISED TO REACH THE
MISSISSIPPI RIVER VALLEY BETWEEN 12 AND 18Z TODAY. SO FAR...THIS
SYSTEM HAS BROUGHT LIGHT PRECIP ACROSS FAR SW KY...AS IT CONTINUES
TO SHIFT EASTWARD TOWARDS OUR SW CWA DURING THE EARLY MORNING HOURS.
THE AMOUNT OF LOW LEVEL DRY AIR IS STILL A CONCERN IN THIS AREA OF
THE CWA...AND WHETHER OR NOT THE PRECIP CAN OVERCOME IT. EXPECTING
BEST CHANCES FOR WEATHER ACROSS WAYNE AND MCCREARY COUNTIES GIVEN
THE LATEST HI RES MODEL DATA...INCLUDING THE HRRR AND ECMWF.
FORECAST SOUNDINGS ARE SHOWING BELOW FREEZING SURFACE TEMPS AT THESE
LOCATIONS...BUT WITH THE POTENTIAL FOR A SLIGHT WARM NOSE TEETERING
ALONG THE FREEZING LINE SEVERAL THOUSAND FEET ABOVE GROUND THROUGH
18Z. AS SUCH...WENT AHEAD AND MENTIONED SOME ICE PELLETS ALONG WITH
A CHANCE OF SNOW IN THESE TWO COUNTIES...WITH A SLIGHT CHANCE OF
LIGHT SNOW EVENTUALLY MIXING WITH RAIN AFTERWARDS ELSEWHERE IN THE
SW CWA.
THE SHORTWAVE WILL EVENTUALLY FLATTEN AND SHIFT EAST OF KY BY 06Z
FRIDAY ELIMINATING ANY FURTHER PRECIP CONCERNS FOR THE SHORT TERM.
THE ONE CAVEAT WILL BE THE EXISTENCE OF THE MID LEVEL CLOUDS WITH
MUCH OF THE TEMPERATURE PROFILE /INCLUDING SURFACE TEMPS/ DROPPING
BELOW FREEZING BY THIS EVENING AND THROUGHOUT THE OVERNIGHT. A FEW
FLURRIES MAY GET SQUEEZED OUT ACROSS THE CWA DURING THE EVENING. IN
FACT...MAY NOT HAVE EXTENDED THE FLURRY POTENTIAL FAR ENOUGH ACROSS
THE CWA. BUT THE CONFIDENCE IS STILL QUITE LOW ON THIS SUBJECT.
CONTINUED TO GO ABOVE GUIDANCE FOR CLOUD COVER OVER THE NEXT 36
HOURS AS MID/LOW LEVEL CLOUDS LOOK TO STICK AROUND THROUGH
FRIDAY...BEFORE ANOTHER ROUND OF HIGH CLOUDS WORKS INTO THE CWA.
THIS MAY INHIBIT SOME OF THE BEST RIDGE VALLEY SPLIT POTENTIAL
TONIGHT. OVERALL...TEMPERATURES SHOULD/T DEVIATE MUCH FROM WHAT WAS
SEEN IN THE PREVIOUS 24 HOURS. HIGHS TODAY WILL GENERALLY BE IN THE
UPPER 30S AND LOW 40S...WITH OVERNIGHT LOWS TONIGHT DROPPING DOWN
INTO THE UPPER 20S. WINDS AT THE SURFACE WILL REMAIN QUITE LIGHT AND
VARIABLE THROUGH THE SHORT TERM...WHILE ABOVE THE CONTINUED MID
LEVEL SUBSIDENCE INVERSION...THEY WILL INCREASE RAPIDLY THANKS TO A
WEST TO EAST ORIENTED JET STREAK WHICH IS CURRENTLY PUSHING ALONG
AND SOUTH OF KY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014
A FAIRLY ACTIVE PATTERN IN STORE FOR THE EXTENDED PORTION OF THE
FORECAST. THE MODELS AREA IN PRETTY GOOD AGREEMENT WITH THE LARGE
SCALE UPPER LEVEL FLOW PATTERN THROUGH MID WEEK. THREE SYSTEMS ARE
FORECAST TO AFFECT EASTERN KENTUCKY...THE FIRST BEING A WEAK AREA OF
LOW PRESSURE THAT IS FORECAST TO FORM OVER THE SOUTHERN PLAINS AND
THEN PROGRESS EASTWARD ACROSS THE GULF COAST FRIDAY NIGHT THROUGH
SATURDAY NIGHT. THE SECOND AND THIRD WEATHER SYSTEMS TO AFFECT THE
REGION...SHOULD THE MODELS PAN OUT...WOULD COME MONDAY THROUGH
WEDNESDAY OF NEXT WEEK. THE FIRST OF THESE LATE PERIOD SYSTEMS IS
PROGGED TO ORIGINATE OVER THE GULF OF MEXICO AND MOVE UP THE EASTERN
SLOPES OF THE APPALACHIAN MOUNTAINS MONDAY AND MONDAY NIGHT. THE
SECOND WEATHER SYSTEM IN THIS SCENARIO IS FORECAST TO TAKE SHAPE
OVER THE NORTHERN PLAINS TO BEGIN THE NEW WORK WEEK. THIS SECOND
SYSTEM WOULD COME IN THE FORM OF A LARGE SCALE AND MUCH DEEPER
TROUGH THAN EITHER OF THE SOUTHERN STREAM SYSTEMS. THIS AREA OF LOW
PRESSURE WOULD PROVIDE THE SOURCE OF COLD AIR THAT COULD BRING SUB
FREEZING TEMPERATURES AND SNOW NEXT WEDNESDAY NIGHT.
THE UNCERTAINTY WITH THIS WEEKENDS WEATHER WILL REVOLVE AROUND HOW
MUCH COLD AIR WILL BE ABLE TO FILTER INTO THE AREA AS THE SOUTHERN
PLAINS LOW MAKES ITS NORTHEASTERN TURN FRIDAY NIGHT. BASED ON THE
LATEST MODEL SOUNDINGS AND TIME HEIGHTS...THERE IS SOME UNCERTAINTY
AS TO HOW FAR SOUTH THE COLD AIR WILL PENETRATE FRIDAY NIGHT INTO
SATURDAY MORNING. BASED ON THIS...DECIDED TO CONFINE ANY
ACCUMULATING SNOW TO THE AREA NORTH OF THE MOUNTAIN PARKWAY BETWEEN
6 AND 12Z FRIDAY NIGHT. THE SNOW SHOULD THEN TRANSITION TO A RAIN
SNOW MIX EARLY SATURDAY MORNING...AND THEN TO ALL RAIN BY EARLY
SATURDAY AFTERNOON. ANY SNOW ACCUMULATIONS THAT DO OCCUR WOULD
LIKELY BE CONFINED TO GRASSY AREAS AND ELEVATED SURFACES. OUR FAR
EASTERN COUNTIES COULD SEE ANOTHER SHOT OF RAIN SNOW MIX OR ALL SNOW
FOR A BRIEF PERIOD SATURDAY NIGHT AS THE LOW EXITS THE AREA AND
WINDS SHIFT TO THE NORTH NORTHEAST. A WEAK RIDGE OF HIGH PRESSURE
ALOFT SHOULD PROVIDE A BRIEF RESPITE FROM THE WINTRY WEATHER LATE
SATURDAY NIGHT THROUGH MID MORNING ON SUNDAY. THE MODELS ONCE AGAIN
OFFER UP SOME UNCERTAINTY AS TO EXACTLY WHEN PRECIPITATION ONSET
WILL BE ON SUNDAY...WITH THE GFS MODEL HOLDING OFF A LOT LONGER THAN
THE ECMWF. BASED ON THIS...WENT WITH A BLEND BETWEEN THE TWO MODELS
FOR PRECIP ONSET ON SUNDAY ACROSS OUR EASTERN COUNTIES...WITH LIGHT
RAIN AFFECTING THE SOUTHEASTERN TWO THIRDS OF THE AREA AS MOISTURE
FROM THE GULF LOW BEGINS TO MOVE NORTHWARD INTO THE AREA. THE BETTER
SHOT OF PRECIPITATION WILL COME FROM MONDAY NIGHT THROUGH WEDNESDAY
EVENING...AS A MUCH STRONGER AND WETTER WEATHER SYSTEM DIVES OUT OF
THE NORTHERN PLAINS AND PHASES WITH WHAT EVER ENERGY IS LEFT OVER
FROM THE GULF OF MEXICO WEATHER SYSTEM. MOST OF THE PRECIPITATION
WITH THIS THIRD WEATHER SYSTEM LOOKS TO BE IN THE FORM OF RAIN BASED
ON THE TEMPERATURE PROFILES SEEN IN THE LATEST MODEL DATA. COULD SEE
SOME MORE SNOW WITH THIS FINAL WEATHER SYSTEM AS WINDS SHIFT TO THE
WEST AND NORTHWEST BEHIND THE LOW AS IT MOVES INTO NEW ENGLAND AND
COLDER AIR SPILLS INTO THE REGION.
THE OTHER WEATHER CONCERN OF NOTE FOR THE END OF THE EXTENDED PERIOD
WILL BE WINDS...PARTICULARLY FROM WEDNESDAY ONWARD. THE MODELS ALL
AGREE THAT A WELL DEVELOPED PRESSURE GRADIENT WILL ACCOMPANY THE
GREAT PLAINS WEATHER SYSTEM AS IT MOVES EAST. SUSTAINED WEST TO
NORTHWEST WINDS OF 10 TO 15 MPH...WITH GUSTS OF 20 TO 25 MPH...WILL
NOT BE OUT OF THE QUESTION. TEMPERATURES THROUGHOUT THE EXTENDED
PERIOD LOOK TO BE AT OR SLIGHTLY ABOVE NORMAL FROM SUNDAY THROUGH
WEDNESDAY. THE WARMEST STRETCH DURING THAT TIME WOULD BE MONDAY AND
TUESDAY...AS WINDS SHIFT TO THE SOUTH AHEAD OF THE MID WEEK WEATHER
SYSTEM. HIGHS ON EACH OF THOSE DAYS ARE EXPECTED TO TOP OUT IN THE
UPPER 40S AND LOWER 50S RESPECTIVELY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 656 AM EST THU DEC 18 2014
AN UPPER LEVEL DISTURBANCE IS BRINGING MOISTURE ACROSS SOUTHERN
KENTUCKY THIS MORNING. SURFACE HIGH PRESSURE...HOWEVER...IS MAKING
IT HARD FOR THE MAJORITY OF THIS MOISTURE TO MAKE IT THROUGH THE
LAYER OF DRY AIR AT THE SURFACE. IT IS POSSIBLE FOR KSME AND KLOZ TO
SEE A FEW SPURTS OF SNOW AND POSSIBLY SLEET AS WE HEAD INTO THE MID
MORNING. HOWEVER...THE LIGHT AND ISOLTED NATURE OF THIS PRECIP IS
NOT LIKELY TO CAUSE VIS RESTRICTIONS...SO CONTINUED TO KEEP MENTION
OF PRECIP OUT OF THE TAF. FOR THE REMAINING TAF SITES...LESS
INFLUENCE FROM THIS UPPER LEVEL DISTURBANCE HAS LEFT HIGH PRESSURE TO
RULE THE SKIES. THIS HAS RESULTED IN A STRONG SUBSIDENCE
INVERSION...TRAPPING LOW LEVEL MOISTURE AND CREATING A MVFR CIG DECK.
EXPECT BOTH THE LLVL CLOUD DECK...AND ANY REMAINING PRECIP
CHANCES...TO DISSIPATE AS WE HEAD INTO THE LATE MORNING/EARLY
AFTERNOON. WHILE WINDS WILL REMAIN LIGHT NEAR THE SURFACE...A WEST TO
EAST ORIENTED UPPER LEVEL JET STREAK WILL KEEP STRONG WESTERLY WIND
FLOW ABOVE THE HIGH PRESSURE INVERSION /AROUND 6K FT AGL/ FOR THE
NEXT 24 HOURS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...JMW
LONG TERM...AR
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
657 AM EST THU DEC 18 2014
.UPDATE...
ISSUED AT 552 AM EST THU DEC 18 2014
THERE IS A FAIR AMOUNT OF RADAR RETURNS MAKING IT INTO SOUTHEAST
KY...UNLIKE WHAT MANY OF THE HI RES MODELS WERE SHOWING EARLIER.
DESPITE THE DRY AIR IN PLACE AT THE SURFACE...DEW POINT DEPRESSIONS
HAVE LESSENED TO 0 IN SOME OF OUR SOUTHWESTERN COUNTIES. AND WITH
SNOW AND SLEET BEING REPORTED ONLY A FEW COUNTIES OVER...DECIDED IT
WAS TIME TO GO AHEAD AND EXPAND THE CHANCES FOR PRECIP THIS MORNING.
AS IT IS NOW...IT LOOKS LIKE ALL OF THE COUNTIES ALONG THE TENNESSEE
BORDER...AS WELL AS THE NEXT TIER OF COUNTIES NORTHWARD WILL LIKELY
BE AFFECTED BY LIGHT SNOW AND POTENTIAL SLEET THIS MORNING. LATEST HI
RES MODELS...INCLUDING THE HRRR AND NAM 12 ARE SHOWING THE SYSTEM
LOSING INTENSITY VERY QUICKLY THIS MORNING...AND CUTTING OFF PRECIP
CHANCES ACROSS OUR CWA WITHIN THE NEXT FEW HOURS. HOWEVER...GIVEN THE
LEVEL OF UNCERTAINTY...AND THE ONGOING STRONG REFLECTIVITIES...ERRED
ON THE PESSIMISTIC SIDE AND KEPT MENTION OF SNOW AND ICE IN UNTIL MID
MORNING. ALSO...WENT AHEAD AND ISSUED A SPECIAL WEATHER STATEMENT
THROUGH 15Z FOR THE AFFECTED COUNTIES SINCE ANY PRECIP WILL LIKELY
ACCUMULATE ON SURFACES DURING THE MORNING COMMUTE.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 358 AM EST THU DEC 18 2014
SURFACE HIGH PRESSURE CONTINUES TO BE IN CHARGE FOR THE OHIO RIVER
VALLEY AND MANY POINTS TO OUR NORTH AND SOUTH. STRONG SUBSIDENCE
TRAPPING LOW LEVEL MOISTURE ACROSS THE NE PORTION OF THE CWA HAS LED
TO CONTINUED MVFR CLOUDS...WHICH ACCORDING TO THE LATEST FORECAST
SOUNDINGS...SHOULDN/T BE BUDGING UNTIL SOMETIME EARLY THIS
AFTERNOON. MEANWHILE...ALOFT...A SHORTWAVE IS CONTINUING TO DAMPEN
AS IT TRACKS EASTWARD...AND SHOULD BE POISED TO REACH THE
MISSISSIPPI RIVER VALLEY BETWEEN 12 AND 18Z TODAY. SO FAR...THIS
SYSTEM HAS BROUGHT LIGHT PRECIP ACROSS FAR SW KY...AS IT CONTINUES
TO SHIFT EASTWARD TOWARDS OUR SW CWA DURING THE EARLY MORNING HOURS.
THE AMOUNT OF LOW LEVEL DRY AIR IS STILL A CONCERN IN THIS AREA OF
THE CWA...AND WHETHER OR NOT THE PRECIP CAN OVERCOME IT. EXPECTING
BEST CHANCES FOR WEATHER ACROSS WAYNE AND MCCREARY COUNTIES GIVEN
THE LATEST HI RES MODEL DATA...INCLUDING THE HRRR AND ECMWF.
FORECAST SOUNDINGS ARE SHOWING BELOW FREEZING SURFACE TEMPS AT THESE
LOCATIONS...BUT WITH THE POTENTIAL FOR A SLIGHT WARM NOSE TEETERING
ALONG THE FREEZING LINE SEVERAL THOUSAND FEET ABOVE GROUND THROUGH
18Z. AS SUCH...WENT AHEAD AND MENTIONED SOME ICE PELLETS ALONG WITH
A CHANCE OF SNOW IN THESE TWO COUNTIES...WITH A SLIGHT CHANCE OF
LIGHT SNOW EVENTUALLY MIXING WITH RAIN AFTERWARDS ELSEWHERE IN THE
SW CWA.
THE SHORTWAVE WILL EVENTUALLY FLATTEN AND SHIFT EAST OF KY BY 06Z
FRIDAY ELIMINATING ANY FURTHER PRECIP CONCERNS FOR THE SHORT TERM.
THE ONE CAVEAT WILL BE THE EXISTENCE OF THE MID LEVEL CLOUDS WITH
MUCH OF THE TEMPERATURE PROFILE /INCLUDING SURFACE TEMPS/ DROPPING
BELOW FREEZING BY THIS EVENING AND THROUGHOUT THE OVERNIGHT. A FEW
FLURRIES MAY GET SQUEEZED OUT ACROSS THE CWA DURING THE EVENING. IN
FACT...MAY NOT HAVE EXTENDED THE FLURRY POTENTIAL FAR ENOUGH ACROSS
THE CWA. BUT THE CONFIDENCE IS STILL QUITE LOW ON THIS SUBJECT.
CONTINUED TO GO ABOVE GUIDANCE FOR CLOUD COVER OVER THE NEXT 36
HOURS AS MID/LOW LEVEL CLOUDS LOOK TO STICK AROUND THROUGH
FRIDAY...BEFORE ANOTHER ROUND OF HIGH CLOUDS WORKS INTO THE CWA.
THIS MAY INHIBIT SOME OF THE BEST RIDGE VALLEY SPLIT POTENTIAL
TONIGHT. OVERALL...TEMPERATURES SHOULD/T DEVIATE MUCH FROM WHAT WAS
SEEN IN THE PREVIOUS 24 HOURS. HIGHS TODAY WILL GENERALLY BE IN THE
UPPER 30S AND LOW 40S...WITH OVERNIGHT LOWS TONIGHT DROPPING DOWN
INTO THE UPPER 20S. WINDS AT THE SURFACE WILL REMAIN QUITE LIGHT AND
VARIABLE THROUGH THE SHORT TERM...WHILE ABOVE THE CONTINUED MID
LEVEL SUBSIDENCE INVERSION...THEY WILL INCREASE RAPIDLY THANKS TO A
WEST TO EAST ORIENTED JET STREAK WHICH IS CURRENTLY PUSHING ALONG
AND SOUTH OF KY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014
A FAIRLY ACTIVE PATTERN IN STORE FOR THE EXTENDED PORTION OF THE
FORECAST. THE MODELS AREA IN PRETTY GOOD AGREEMENT WITH THE LARGE
SCALE UPPER LEVEL FLOW PATTERN THROUGH MID WEEK. THREE SYSTEMS ARE
FORECAST TO AFFECT EASTERN KENTUCKY...THE FIRST BEING A WEAK AREA OF
LOW PRESSURE THAT IS FORECAST TO FORM OVER THE SOUTHERN PLAINS AND
THEN PROGRESS EASTWARD ACROSS THE GULF COAST FRIDAY NIGHT THROUGH
SATURDAY NIGHT. THE SECOND AND THIRD WEATHER SYSTEMS TO AFFECT THE
REGION...SHOULD THE MODELS PAN OUT...WOULD COME MONDAY THROUGH
WEDNESDAY OF NEXT WEEK. THE FIRST OF THESE LATE PERIOD SYSTEMS IS
PROGGED TO ORIGINATE OVER THE GULF OF MEXICO AND MOVE UP THE EASTERN
SLOPES OF THE APPALACHIAN MOUNTAINS MONDAY AND MONDAY NIGHT. THE
SECOND WEATHER SYSTEM IN THIS SCENARIO IS FORECAST TO TAKE SHAPE
OVER THE NORTHERN PLAINS TO BEGIN THE NEW WORK WEEK. THIS SECOND
SYSTEM WOULD COME IN THE FORM OF A LARGE SCALE AND MUCH DEEPER
TROUGH THAN EITHER OF THE SOUTHERN STREAM SYSTEMS. THIS AREA OF LOW
PRESSURE WOULD PROVIDE THE SOURCE OF COLD AIR THAT COULD BRING SUB
FREEZING TEMPERATURES AND SNOW NEXT WEDNESDAY NIGHT.
THE UNCERTAINTY WITH THIS WEEKENDS WEATHER WILL REVOLVE AROUND HOW
MUCH COLD AIR WILL BE ABLE TO FILTER INTO THE AREA AS THE SOUTHERN
PLAINS LOW MAKES ITS NORTHEASTERN TURN FRIDAY NIGHT. BASED ON THE
LATEST MODEL SOUNDINGS AND TIME HEIGHTS...THERE IS SOME UNCERTAINTY
AS TO HOW FAR SOUTH THE COLD AIR WILL PENETRATE FRIDAY NIGHT INTO
SATURDAY MORNING. BASED ON THIS...DECIDED TO CONFINE ANY
ACCUMULATING SNOW TO THE AREA NORTH OF THE MOUNTAIN PARKWAY BETWEEN
6 AND 12Z FRIDAY NIGHT. THE SNOW SHOULD THEN TRANSITION TO A RAIN
SNOW MIX EARLY SATURDAY MORNING...AND THEN TO ALL RAIN BY EARLY
SATURDAY AFTERNOON. ANY SNOW ACCUMULATIONS THAT DO OCCUR WOULD
LIKELY BE CONFINED TO GRASSY AREAS AND ELEVATED SURFACES. OUR FAR
EASTERN COUNTIES COULD SEE ANOTHER SHOT OF RAIN SNOW MIX OR ALL SNOW
FOR A BRIEF PERIOD SATURDAY NIGHT AS THE LOW EXITS THE AREA AND
WINDS SHIFT TO THE NORTH NORTHEAST. A WEAK RIDGE OF HIGH PRESSURE
ALOFT SHOULD PROVIDE A BRIEF RESPITE FROM THE WINTRY WEATHER LATE
SATURDAY NIGHT THROUGH MID MORNING ON SUNDAY. THE MODELS ONCE AGAIN
OFFER UP SOME UNCERTAINTY AS TO EXACTLY WHEN PRECIPITATION ONSET
WILL BE ON SUNDAY...WITH THE GFS MODEL HOLDING OFF A LOT LONGER THAN
THE ECMWF. BASED ON THIS...WENT WITH A BLEND BETWEEN THE TWO MODELS
FOR PRECIP ONSET ON SUNDAY ACROSS OUR EASTERN COUNTIES...WITH LIGHT
RAIN AFFECTING THE SOUTHEASTERN TWO THIRDS OF THE AREA AS MOISTURE
FROM THE GULF LOW BEGINS TO MOVE NORTHWARD INTO THE AREA. THE BETTER
SHOT OF PRECIPITATION WILL COME FROM MONDAY NIGHT THROUGH WEDNESDAY
EVENING...AS A MUCH STRONGER AND WETTER WEATHER SYSTEM DIVES OUT OF
THE NORTHERN PLAINS AND PHASES WITH WHAT EVER ENERGY IS LEFT OVER
FROM THE GULF OF MEXICO WEATHER SYSTEM. MOST OF THE PRECIPITATION
WITH THIS THIRD WEATHER SYSTEM LOOKS TO BE IN THE FORM OF RAIN BASED
ON THE TEMPERATURE PROFILES SEEN IN THE LATEST MODEL DATA. COULD SEE
SOME MORE SNOW WITH THIS FINAL WEATHER SYSTEM AS WINDS SHIFT TO THE
WEST AND NORTHWEST BEHIND THE LOW AS IT MOVES INTO NEW ENGLAND AND
COLDER AIR SPILLS INTO THE REGION.
THE OTHER WEATHER CONCERN OF NOTE FOR THE END OF THE EXTENDED PERIOD
WILL BE WINDS...PARTICULARLY FROM WEDNESDAY ONWARD. THE MODELS ALL
AGREE THAT A WELL DEVELOPED PRESSURE GRADIENT WILL ACCOMPANY THE
GREAT PLAINS WEATHER SYSTEM AS IT MOVES EAST. SUSTAINED WEST TO
NORTHWEST WINDS OF 10 TO 15 MPH...WITH GUSTS OF 20 TO 25 MPH...WILL
NOT BE OUT OF THE QUESTION. TEMPERATURES THROUGHOUT THE EXTENDED
PERIOD LOOK TO BE AT OR SLIGHTLY ABOVE NORMAL FROM SUNDAY THROUGH
WEDNESDAY. THE WARMEST STRETCH DURING THAT TIME WOULD BE MONDAY AND
TUESDAY...AS WINDS SHIFT TO THE SOUTH AHEAD OF THE MID WEEK WEATHER
SYSTEM. HIGHS ON EACH OF THOSE DAYS ARE EXPECTED TO TOP OUT IN THE
UPPER 40S AND LOWER 50S RESPECTIVELY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 656 AM EST THU DEC 18 2014
AN UPPER LEVEL DISTURBANCE IS BRINGING MOISTURE ACROSS SOUTHERN
KENTUCKY THIS MORNING. SURFACE HIGH PRESSURE...HOWEVER...IS MAKING
IT HARD FOR THE MAJORITY OF THIS MOISTURE TO MAKE IT THROUGH THE
LAYER OF DRY AIR AT THE SURFACE. IT IS POSSIBLE FOR KSME AND KLOZ TO
SEE A FEW SPURTS OF SNOW AND POSSIBLY SLEET AS WE HEAD INTO THE MID
MORNING. HOWEVER...THE LIGHT AND ISOLTED NATURE OF THIS PRECIP IS
NOT LIKELY TO CAUSE VIS RESTRICTIONS...SO CONTINUED TO KEEP MENTION
OF PRECIP OUT OF THE TAF. FOR THE REMAINING TAF SITES...LESS
INFLUENCE FROM THIS UPPER LEVEL DISTURBANCE HAS LEFT HIGH PRESSURE TO
RULE THE SKIES. THIS HAS RESULTED IN A STRONG SUBSIDENCE
INVERSION...TRAPPING LOW LEVEL MOISTURE AND CREATING A MVFR CIG DECK.
EXPECT BOTH THE LLVL CLOUD DECK...AND ANY REMAINING PRECIP
CHANCES...TO DISSIPATE AS WE HEAD INTO THE LATE MORNING/EARLY
AFTERNOON. WHILE WINDS WILL REMAIN LIGHT NEAR THE SURFACE...A WEST TO
EAST ORIENTED UPPER LEVEL JET STREAK WILL KEEP STRONG WESTERLY WIND
FLOW ABOVE THE HIGH PRESSURE INVERSION /AROUND 6K FT AGL/ FOR THE
NEXT 24 HOURS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...JMW
LONG TERM...AR
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
553 AM EST THU DEC 18 2014
.UPDATE...
ISSUED AT 552 AM EST THU DEC 18 2014
THERE IS A FAIR AMOUNT OF RADAR RETURNS MAKING IT INTO SOUTHEAST
KY...UNLIKE WHAT MANY OF THE HI RES MODELS WERE SHOWING EARLIER.
DESPITE THE DRY AIR IN PLACE AT THE SURFACE...DEW POINT DEPRESSIONS
HAVE LESSENED TO 0 IN SOME OF OUR SOUTHWESTERN COUNTIES. AND WITH
SNOW AND SLEET BEING REPORTED ONLY A FEW COUNTIES OVER...DECIDED IT
WAS TIME TO GO AHEAD AND EXPAND THE CHANCES FOR PRECIP THIS MORNING.
AS IT IS NOW...IT LOOKS LIKE ALL OF THE COUNTIES ALONG THE TENNESSEE
BORDER...AS WELL AS THE NEXT TIER OF COUNTIES NORTHWARD WILL LIKELY
BE AFFECTED BY LIGHT SNOW AND POTENTIAL SLEET THIS MORNING. LATEST HI
RES MODELS...INCLUDING THE HRRR AND NAM 12 ARE SHOWING THE SYSTEM
LOSING INTENSITY VERY QUICKLY THIS MORNING...AND CUTTING OFF PRECIP
CHANCES ACROSS OUR CWA WITHIN THE NEXT FEW HOURS. HOWEVER...GIVEN THE
LEVEL OF UNCERTAINTY...AND THE ONGOING STRONG REFLECTIVITIES...ERRED
ON THE PESSIMISTIC SIDE AND KEPT MENTION OF SNOW AND ICE IN UNTIL MID
MORNING. ALSO...WENT AHEAD AND ISSUED A SPECIAL WEATHER STATEMENT
THROUGH 15Z FOR THE AFFECTED COUNTIES SINCE ANY PRECIP WILL LIKELY
ACCUMULATE ON SURFACES DURING THE MORNING COMMUTE.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 358 AM EST THU DEC 18 2014
SURFACE HIGH PRESSURE CONTINUES TO BE IN CHARGE FOR THE OHIO RIVER
VALLEY AND MANY POINTS TO OUR NORTH AND SOUTH. STRONG SUBSIDENCE
TRAPPING LOW LEVEL MOISTURE ACROSS THE NE PORTION OF THE CWA HAS LED
TO CONTINUED MVFR CLOUDS...WHICH ACCORDING TO THE LATEST FORECAST
SOUNDINGS...SHOULDN/T BE BUDGING UNTIL SOMETIME EARLY THIS
AFTERNOON. MEANWHILE...ALOFT...A SHORTWAVE IS CONTINUING TO DAMPEN
AS IT TRACKS EASTWARD...AND SHOULD BE POISED TO REACH THE
MISSISSIPPI RIVER VALLEY BETWEEN 12 AND 18Z TODAY. SO FAR...THIS
SYSTEM HAS BROUGHT LIGHT PRECIP ACROSS FAR SW KY...AS IT CONTINUES
TO SHIFT EASTWARD TOWARDS OUR SW CWA DURING THE EARLY MORNING HOURS.
THE AMOUNT OF LOW LEVEL DRY AIR IS STILL A CONCERN IN THIS AREA OF
THE CWA...AND WHETHER OR NOT THE PRECIP CAN OVERCOME IT. EXPECTING
BEST CHANCES FOR WEATHER ACROSS WAYNE AND MCCREARY COUNTIES GIVEN
THE LATEST HI RES MODEL DATA...INCLUDING THE HRRR AND ECMWF.
FORECAST SOUNDINGS ARE SHOWING BELOW FREEZING SURFACE TEMPS AT THESE
LOCATIONS...BUT WITH THE POTENTIAL FOR A SLIGHT WARM NOSE TEETERING
ALONG THE FREEZING LINE SEVERAL THOUSAND FEET ABOVE GROUND THROUGH
18Z. AS SUCH...WENT AHEAD AND MENTIONED SOME ICE PELLETS ALONG WITH
A CHANCE OF SNOW IN THESE TWO COUNTIES...WITH A SLIGHT CHANCE OF
LIGHT SNOW EVENTUALLY MIXING WITH RAIN AFTERWARDS ELSEWHERE IN THE
SW CWA.
THE SHORTWAVE WILL EVENTUALLY FLATTEN AND SHIFT EAST OF KY BY 06Z
FRIDAY ELIMINATING ANY FURTHER PRECIP CONCERNS FOR THE SHORT TERM.
THE ONE CAVEAT WILL BE THE EXISTENCE OF THE MID LEVEL CLOUDS WITH
MUCH OF THE TEMPERATURE PROFILE /INCLUDING SURFACE TEMPS/ DROPPING
BELOW FREEZING BY THIS EVENING AND THROUGHOUT THE OVERNIGHT. A FEW
FLURRIES MAY GET SQUEEZED OUT ACROSS THE CWA DURING THE EVENING. IN
FACT...MAY NOT HAVE EXTENDED THE FLURRY POTENTIAL FAR ENOUGH ACROSS
THE CWA. BUT THE CONFIDENCE IS STILL QUITE LOW ON THIS SUBJECT.
CONTINUED TO GO ABOVE GUIDANCE FOR CLOUD COVER OVER THE NEXT 36
HOURS AS MID/LOW LEVEL CLOUDS LOOK TO STICK AROUND THROUGH
FRIDAY...BEFORE ANOTHER ROUND OF HIGH CLOUDS WORKS INTO THE CWA.
THIS MAY INHIBIT SOME OF THE BEST RIDGE VALLEY SPLIT POTENTIAL
TONIGHT. OVERALL...TEMPERATURES SHOULD/T DEVIATE MUCH FROM WHAT WAS
SEEN IN THE PREVIOUS 24 HOURS. HIGHS TODAY WILL GENERALLY BE IN THE
UPPER 30S AND LOW 40S...WITH OVERNIGHT LOWS TONIGHT DROPPING DOWN
INTO THE UPPER 20S. WINDS AT THE SURFACE WILL REMAIN QUITE LIGHT AND
VARIABLE THROUGH THE SHORT TERM...WHILE ABOVE THE CONTINUED MID
LEVEL SUBSIDENCE INVERSION...THEY WILL INCREASE RAPIDLY THANKS TO A
WEST TO EAST ORIENTED JET STREAK WHICH IS CURRENTLY PUSHING ALONG
AND SOUTH OF KY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014
A FAIRLY ACTIVE PATTERN IN STORE FOR THE EXTENDED PORTION OF THE
FORECAST. THE MODELS AREA IN PRETTY GOOD AGREEMENT WITH THE LARGE
SCALE UPPER LEVEL FLOW PATTERN THROUGH MID WEEK. THREE SYSTEMS ARE
FORECAST TO AFFECT EASTERN KENTUCKY...THE FIRST BEING A WEAK AREA OF
LOW PRESSURE THAT IS FORECAST TO FORM OVER THE SOUTHERN PLAINS AND
THEN PROGRESS EASTWARD ACROSS THE GULF COAST FRIDAY NIGHT THROUGH
SATURDAY NIGHT. THE SECOND AND THIRD WEATHER SYSTEMS TO AFFECT THE
REGION...SHOULD THE MODELS PAN OUT...WOULD COME MONDAY THROUGH
WEDNESDAY OF NEXT WEEK. THE FIRST OF THESE LATE PERIOD SYSTEMS IS
PROGGED TO ORIGINATE OVER THE GULF OF MEXICO AND MOVE UP THE EASTERN
SLOPES OF THE APPALACHIAN MOUNTAINS MONDAY AND MONDAY NIGHT. THE
SECOND WEATHER SYSTEM IN THIS SCENARIO IS FORECAST TO TAKE SHAPE
OVER THE NORTHERN PLAINS TO BEGIN THE NEW WORK WEEK. THIS SECOND
SYSTEM WOULD COME IN THE FORM OF A LARGE SCALE AND MUCH DEEPER
TROUGH THAN EITHER OF THE SOUTHERN STREAM SYSTEMS. THIS AREA OF LOW
PRESSURE WOULD PROVIDE THE SOURCE OF COLD AIR THAT COULD BRING SUB
FREEZING TEMPERATURES AND SNOW NEXT WEDNESDAY NIGHT.
THE UNCERTAINTY WITH THIS WEEKENDS WEATHER WILL REVOLVE AROUND HOW
MUCH COLD AIR WILL BE ABLE TO FILTER INTO THE AREA AS THE SOUTHERN
PLAINS LOW MAKES ITS NORTHEASTERN TURN FRIDAY NIGHT. BASED ON THE
LATEST MODEL SOUNDINGS AND TIME HEIGHTS...THERE IS SOME UNCERTAINTY
AS TO HOW FAR SOUTH THE COLD AIR WILL PENETRATE FRIDAY NIGHT INTO
SATURDAY MORNING. BASED ON THIS...DECIDED TO CONFINE ANY
ACCUMULATING SNOW TO THE AREA NORTH OF THE MOUNTAIN PARKWAY BETWEEN
6 AND 12Z FRIDAY NIGHT. THE SNOW SHOULD THEN TRANSITION TO A RAIN
SNOW MIX EARLY SATURDAY MORNING...AND THEN TO ALL RAIN BY EARLY
SATURDAY AFTERNOON. ANY SNOW ACCUMULATIONS THAT DO OCCUR WOULD
LIKELY BE CONFINED TO GRASSY AREAS AND ELEVATED SURFACES. OUR FAR
EASTERN COUNTIES COULD SEE ANOTHER SHOT OF RAIN SNOW MIX OR ALL SNOW
FOR A BRIEF PERIOD SATURDAY NIGHT AS THE LOW EXITS THE AREA AND
WINDS SHIFT TO THE NORTH NORTHEAST. A WEAK RIDGE OF HIGH PRESSURE
ALOFT SHOULD PROVIDE A BRIEF RESPITE FROM THE WINTRY WEATHER LATE
SATURDAY NIGHT THROUGH MID MORNING ON SUNDAY. THE MODELS ONCE AGAIN
OFFER UP SOME UNCERTAINTY AS TO EXACTLY WHEN PRECIPITATION ONSET
WILL BE ON SUNDAY...WITH THE GFS MODEL HOLDING OFF A LOT LONGER THAN
THE ECMWF. BASED ON THIS...WENT WITH A BLEND BETWEEN THE TWO MODELS
FOR PRECIP ONSET ON SUNDAY ACROSS OUR EASTERN COUNTIES...WITH LIGHT
RAIN AFFECTING THE SOUTHEASTERN TWO THIRDS OF THE AREA AS MOISTURE
FROM THE GULF LOW BEGINS TO MOVE NORTHWARD INTO THE AREA. THE BETTER
SHOT OF PRECIPITATION WILL COME FROM MONDAY NIGHT THROUGH WEDNESDAY
EVENING...AS A MUCH STRONGER AND WETTER WEATHER SYSTEM DIVES OUT OF
THE NORTHERN PLAINS AND PHASES WITH WHAT EVER ENERGY IS LEFT OVER
FROM THE GULF OF MEXICO WEATHER SYSTEM. MOST OF THE PRECIPITATION
WITH THIS THIRD WEATHER SYSTEM LOOKS TO BE IN THE FORM OF RAIN BASED
ON THE TEMPERATURE PROFILES SEEN IN THE LATEST MODEL DATA. COULD SEE
SOME MORE SNOW WITH THIS FINAL WEATHER SYSTEM AS WINDS SHIFT TO THE
WEST AND NORTHWEST BEHIND THE LOW AS IT MOVES INTO NEW ENGLAND AND
COLDER AIR SPILLS INTO THE REGION.
THE OTHER WEATHER CONCERN OF NOTE FOR THE END OF THE EXTENDED PERIOD
WILL BE WINDS...PARTICULARLY FROM WEDNESDAY ONWARD. THE MODELS ALL
AGREE THAT A WELL DEVELOPED PRESSURE GRADIENT WILL ACCOMPANY THE
GREAT PLAINS WEATHER SYSTEM AS IT MOVES EAST. SUSTAINED WEST TO
NORTHWEST WINDS OF 10 TO 15 MPH...WITH GUSTS OF 20 TO 25 MPH...WILL
NOT BE OUT OF THE QUESTION. TEMPERATURES THROUGHOUT THE EXTENDED
PERIOD LOOK TO BE AT OR SLIGHTLY ABOVE NORMAL FROM SUNDAY THROUGH
WEDNESDAY. THE WARMEST STRETCH DURING THAT TIME WOULD BE MONDAY AND
TUESDAY...AS WINDS SHIFT TO THE SOUTH AHEAD OF THE MID WEEK WEATHER
SYSTEM. HIGHS ON EACH OF THOSE DAYS ARE EXPECTED TO TOP OUT IN THE
UPPER 40S AND LOWER 50S RESPECTIVELY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1245 AM EST THU DEC 18 2014
HIGH PRESSURE OVERHEAD IS KEEPING A STRONG SUBSIDENCE INVERSION IN
PLACE ACROSS MUCH OF THE NORTHERN HALF OF THE CWA...TRAPPING LOW LEVEL
MOISTURE AND RESULTING IN OVC MVFR CIGS...INCLUDING AT KSJS AND KSYM
/AND IMPOSING ON KJKL FAIRLY QUICKLY/. MEANWHILE...A WEAK UPPER LEVEL
DISTURBANCE IS MOVING INTO THE MISSISSIPPI RIVER VALLEY...SPREADING
AN AREA OF HIGH CLOUDS OUT AHEAD OF IT. EXPECT THE SOUTHWARD
PROGRESSION OF THE LOW CLOUDS TO BE STOPPED BY THE INCOMING
DISTURBANCE...AND MVFR CIGS TO SIT IN PLACE OVER THE AFFECTED TAF
SITES THROUGH THE REMAINDER OF THE NIGHT. MODELS ARE STILL SHOWING
THIS DISTURBANCE BRINGING A CHANCE OF LIGHT PRECIP TO KSYM AND KLOZ.
HOWEVER...GIVEN THE STRONG SURGE OF LOW LEVEL DRY AIR IN THIS AREA /WHERE
LOW LEVEL CLOUD COVER HAS NOT BEEN A FACTOR/...IT WILL BE HARD FOR
ANY PRECIP TO REACH THE GROUND. MAY NOT RULE OUT SOME SPRINKLES OR
FLURRIES AS CIGS LOWER TO AROUND 5 TO 7K FT BETWEEN 10 AND 14Z THIS
MORNING...BUT GIVEN LOW CONFIDENCE AND MINIMAL IMPACTS...DID NOT
INCLUDE IN TAFS AT THIS TIME. ANY LINGERING LOW LEVEL CLOUDS LOOK TO
BREAK BETWEEN 15 AND 18Z TODAY. OTHERWISE...WHILE WESTERLY WINDS
ALOFT CONTINUE TO BE VERY STRONG...EXPECT LIGHT AND VARIABLE WINDS
WITHIN THE FIRST FEW THOUSAND FEET AGL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...JMW
LONG TERM...AR
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
957 AM CST THU DEC 18 2014
.UPDATE...
WARM FRONTAL BOUNDARY SITTING OFF THE COAST MAKING FOR A MESSY
WEATHER PICTURE TODAY THROUGH FRIDAY. LOOKING AT THE CURRENT RADAR...
AN AREA OF RAIN AND SHOWERS ORIENTED SOUTHWEST TO NORTHEAST WILL
CONTINUE TO SLIDE EAST AND FILL IN SOUTHWARD CLOSE TO THE WARM FRONT.
UPDATED RAIN CHANCES REST OF THIS MORNING INTO THIS AFTERNOON TO COME
INTO AGREEMENT WITH THE LOCAL WRF MODEL AS WELL AS THE HIGH
RESOLUTION HRRR WHICH ARE BOTH SIGNALING RAIN COVERAGE INCREASING
THROUGHOUT THE DAY. TEMPERATURES LOOK REASONABLE...ONLY ADJUSTED DOWN
ONE TINY NOTCH. INCREASED CLOUD COVER TODAY AS WELL...IT IS GOING
TO BE MOSTLY CLOUDY FOR THE REMAINDER OF THE DAY.
&&
.PREV DISCUSSION... /ISSUED 545 AM CST THU DEC 18 2014/
AVIATION UPDATE...REGARDING 12Z TAF ISSUANCE. MVFR CEILINGS NOW
OVER OUR TERMINALS OF AEX AND BPT WILL OVERSPREAD THE REMAINDER OF
THE AREA AS THE MORNING PROGRESSES. THIS NORTH OF A WARM FRONT NOW
OVER THE NEAR COASTAL WATERS THAT IS EXPECTED TO RETREAT INTO THE
INLAND AREA THROUGH THE DAY. SCATTERED SHOWERS ARE ON TAP ALONG AND
AHEAD OF THE BOUNDARY. CARRYING VCSH AND TEMPO GROUPS AT VARIOUS
TIMES AT ALL TERMINALS. RAIN CHANCES THEN DIMINISH BY EARLY
EVENING...RAMPING UP AGAIN LATE TONIGHT WITH THE APPROACH OF A
SHORTWAVE TROF ADVANCING EAST ACROSS TEXAS.
MARCOTTE
PREV DISCUSSION... /ISSUED 501 AM CST THU DEC 18 2014/
DISCUSSION...
TEMPERATURES AROUND THE NATION RANGED FROM SINGLE DIGITS ACROSS
THE UPPER PLAINS STATES TO THE LOWER 70S AT BROWNSVILLE IN DEEP
SOUTH TEXAS.
THE WEATHER TODAY LOOKS TO BE A MESS AS WE BEGIN ANOTHER TRANSITION
TO A COLD FRONTAL PASSAGE LATE FRIDAY TIME FRAME. UNTIL THEN A
SURFACE LOW IS DEVELOPING OVER DEEP SOUTH TEXAS AND WILL LIFT
NORTHEAST TODAY DRAGGING WITH IT A WARM FRONT. RAINS TODAY ARE
GOING TO RIDE UP AND OVER THE WARM FRONT THAT IS LOCATED TO OUR
SOUTHWEST THIS MORNING. ISOLATED THUNDERSTORMS THIS AFTERNOON INTO
TONIGHT. TEMPS WILL RANGE FROM NEAR 70 BEHIND THE WARM FRONT IN
BEAUMONT TO 60 FOR THE LAKES REGION IN SOUTHEAST TEXAS AND CENTRAL
LOUISIANA UNDER CLOUDY SKIES. WINDS WILL REMAIN FROM THE NORTHEAST
INLAND TO EAST ALONG THE COAST TO SOUTHEAST IN THE COASTAL WATERS.
TONIGHT WILL SEE SHOWERS AND ISOLATED THUNDERSTORMS... TEMPERATURES
NOT AS COOL AS THIS MORNING AS THE WARM FRONT WILL LAY ALONG THE
I-10 CORRIDOR. THIS BOUNDARY WILL MORE OR LESS REMAIN STATIONARY
INTO FRIDAY MORNING TIME FRAME. SOUTH OF THE WARM FRONT THERE WILL
BE IS A CHANCE THAT SEVERAL STORMS MAY BECOME SEVERE WITH WINDS
THE MAIN THREAT. HEAVY RAINS ARE ALSO EXPECTED FOR THE LAKES
REGION IN SOUTHEAST TEXAS AND ACROSS CENTRAL LOUISIANA NORTH OF
THE WARM FRONT. AS THE LOW MOVES INTO SOUTHERN LOUISIANA ON FRIDAY
THIS WILL DRAG COOLER AND DRIER AIR DOWN INTO TEXAS WITH A COLD
FRONT PUSHING INTO SOUTHEAST TEXAS LATE IN THE DAY. THIS LATEST
FRONT IS EXPECTED TO EXIT SOUTH CENTRAL LOUISIANA FRIDAY EVENING
WITH RAINS ENDING EARLY SATURDAY MORNING. THE WEEKEND LOOKS TO BE
COOLER AND DRIER ALTHOUGH IT WILL TAKE AWHILE TO DRY OUT.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 65 55 64 46 / 60 60 90 30
KBPT 69 57 66 47 / 50 70 90 20
KAEX 56 50 53 42 / 50 70 90 50
KLFT 66 56 65 48 / 50 40 90 40
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE...06
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
637 AM EST THU DEC 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM EST THU DEC 18 2014
AN UPPER RIDGE STRETCHING FROM MINNESOTA THROUGH NORTHWEST ONTARIO
WILL BE THE MAIN FEATURE CONTROLLING THE WEATHER OVER THE UPPER
GREAT LAKES REGION OVER THE NEXT 24 HOURS. BENEATH THIS UPPER
RIDGE...A 1029MB SURFACE HIGH SITS JUST TO THE NORTH OF THE
MINNESOTA WHILE THE SURFACE TROUGH THAT LED TO THE SNOW YESTERDAY
IS OVER NORTHERN LAKE MICHIGAN AND NORTHERN LOWER MICHIGAN AND
WEAKENING. NORTH-NORTHEASTERLY FLOW AROUND THIS HIGH HAS PULLED
DRIER AIR INTO THE UPPER GREAT LAKES REGION...LEADING TO CLEARING
SKIES THIS PAST EVENING OVER MUCH OF LAKE SUPERIOR. BUT MOISTURE
TRAPPED BELOW THE SUBSIDENCE INVERSION...AND COMBINED WITH UPSLOPE
FLOW...HAS LED TO LOW CLOUDS PERSISTING OVER A GOOD PORTION OF
UPPER MICHIGAN EARLY THIS MORNING. THERE ARE A COUPLE SPOTS WHERE
THE CLOUDS DID CLEAR OUT...GENERALLY OVER THE KEWEENAW PENINSULA
AND ALSO IT/S STARTING TO OVER THE EAST. WHERE SKIES CLEARED
OUT...3AM TEMPERATURES ARE IN THE SINGLE DIGITS ABOVE ZERO (6
DEGREES AT KCMX)...WHILE THE CLOUDS HAVE KEPT THE TEMPERATURES IN
THE UPPER TEENS AND LOWER 20S ELSEWHERE. STILL SEEING LIGHT
FLURRIES HERE AT OUR OFFICE AT 330AM...SO WILL CONTINUE TO MENTION
ISOLATED FLURRIES IN THE FORECAST FOR THE UPSLOPE LOCATIONS THROUGH
DAYBREAK.
WITH THE UPPER RIDGE AND SURFACE HIGH MOVING OVER THE AREA
TODAY...EXPECT CONTINUED QUIET CONDITIONS FOR THE SHORT TERM
PERIOD. THERE ARE TWO AREAS OF FOCUS IN THE SHORT TERM
PERIOD...FIRST THE LOW CLOUDS AND THEIR DIMINISHMENT AND THEN THE
POTENTIAL FOR SOME FREEZING FOG OVERNIGHT TONIGHT. FOR THE LOW
CLOUDS...KMQT VWP INDICATES CLOUD TOPS AROUND 2.5KFT...WHICH
MATCHES UP WELL WITH THE INVERSION INDICATED ON THE MODELS AT
900MB. THE BIG QUESTION IS WHEN WILL THEY DISSIPATE TODAY. AT
THIS TIME OF THE YEAR WITH THE LOW SUN ANGLE AND LIMITED
MIXING...THERE IS LITTLE DAY TIME HELP AND WILL NEED TO RELY ON THE
ADVECTION OF DRIER AIR INTO THE AREA. UNFORTUNATELY...THIS IS WHERE
THE MODELS TEND TO DIFFER. THE 00Z NAM HOLDS ONTO THE CLOUDS FOR
MUCH OF THE DAY AND EVEN THROUGH THE NIGHT TONIGHT...BUT THINK THAT
IS LARGELY TIED TO IT TRADITIONALLY OVER DOING LOW LEVEL MOISTURE.
THAT APPEARS TO THE CASE EARLY THIS MORNING...WHERE IT HAS THE LOW
CLOUDS JUST TO THE WEST OF JAMES BAY BEING MUCH FARTHER TO THE
SOUTH AND SUPPOSEDLY ENTERING NORTHERN LAKE SUPERIOR AT THIS TIME.
THE RECENT RAP (ALONG WITH THE HRRR) RUNS ALSO HOLD ONTO THE CLOUDS
FOR MUCH OF THE DAY BEFORE CLEARING THEM OUT THIS AFTERNOON...BUT IT
APPEARS TO HAVE THE LOW LEVEL MOISTURE FARTHER NORTH OVER LAKE
SUPERIOR THAN WHAT IS ACTUALLY OCCURRING. THE MORE OPTIMISTIC
RUNS...WHICH SEEM TO HAVE A BETTER HANDLE ON THE LOCATION OF THE
LOW CLOUDS ARE THE 00Z GFS/ECMWF. THEY HOLD ONTO THE LOW CLOUDS
OVER THE NORTH CENTRAL AND WEST FOR THE FIRST PART OF THE MORNING
AND THEN SCATTER THEM OUT THROUGH THE LATER PART OF THE MORNING AND
EARLY AFTERNOON. WILL FOLLOW THAT IDEA AT THIS POINT FOR THE CLOUD
COVER FORECAST FOR TODAY. MEANWHILE OVER THE EAST...THE ADVECTION
OF THE DRIER AIR AND LITTLE UPSLOPE HELP SHOULD ALLOW THE LOW
CLOUDS TO DISSIPATE DURING THE FIRST PART OF THE MORNING. THAT DRY
AIR HAS ALREADY SCATTERED THE CLOUDS OUT OVER LUCE COUNTY AND
STARTING TO SEE IT WORK INTO ALGER/SCHOOLCRAFT COUNTIES. AS FOR
HIGHS TODAY...EXPECT THEM TO BE IN THE MID-UPPER 20S OVER MUCH OF
THE AREA.
FOLLOWING THE IDEA OF THE CLOUDS DIMINISHING TODAY...WOULD EXPECT A
VERY GOOD RADIATIONAL COOLING NIGHT TONIGHT UNDER THE CENTER OF THE
HIGH. THUS...WILL CONTINUE THE IDEA OF GOING AT OR BELOW THE
COLDEST GUIDANCE. THE GEM MODELS USUALLY PERFORM WELL IN
RADIATIONAL COOLING NIGHTS AND THEY HAVE LOWS IN THE LOWER SINGLE
DIGITS WHERE THEY ARE NOT INDICATING CLOUDS (ALTHOUGH THE REGIONAL
GEM REDEVELOPS LOW CLOUDS OVER THE HIGHER TERRAIN OF THE NORTH
CENTRAL TONIGHT). THUS...HAVE LOWS IN THE SINGLE DIGITS ABOVE ZERO
TO AROUND ZERO OVER THE INTERIOR LOCATIONS. WITH KCMX DROPPING TO 6
DEGREES AT 3AM THIS MORNING...THAT SUPPORTS TO EXPECTATIONS FOR
TONIGHT. THIS EXPECTED DROP IN TEMPS WILL LEAD TO THE POTENTIAL FOR
PATCHY FREEZING FOG OR AT LEAST SOME SOLID FROST. WITH DEWPOINTS IN
THE MID-UPPER TEENS TODAY...TEMPS SHOULD EASILY DROP THROUGH THOSE
VALUES THIS EVENING. DEWPOINTS THIS PAST EVENING AT KCMX WERE
SIMILAR TO WHAT IS EXPECTED ACROSS THE REST OF THE AREA THIS
AFTERNOON. WITH THEIR QUICK TEMP DROP AND LIGHT WINDS...THEY HAVEN/T
EXPERIENCED ANY FOG AT THIS POINT...BUT THE ICE ACCRETION ALGORITHM
DID INDICATE SOME ICE ACCUMULATION. THIS IS LIKELY DUE TO THAT QUICK
DROP AND IN TURN SOME QUICK/HARD FROST ON THE SENSOR. IT WILL BE
INTERESTING TO SEE IF ANY VERY SHALLOW FOG DEVELOPS AT KCMX OVER
THE NEXT COUPLE HOURS...AS IT WILL FORESHADOW WHAT WILL OCCUR
TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 514 AM EST THU DEC 18 2014
FRIDAY...A DRY AIRMASS ASSOCIATED WITH THE DEPARTING AREA OF
HIGH PRESSURE WILL LEAVE PARTLY TO MOSTLY SUNNY SKIES ACROSS UPPER
MICHIGAN. HOWEVER...THERE IS SOME UNCERTAINTY WHETHER MOISTURE
BENEATH THE PROMINENT 925 MB INVERSION WILL LINGER ENOUGH FOR MOSTLY
CLOUDY SKIES...ESPECIALLY OVER THE WEST. EVEN WITH SOME
CLOUDS...TEMPS ARE EXPECTED TO CLIMB INTO THE UPPER 20S.
FRI NIGHT...TEMPS SHOULD DROP OFF QUICKLY IN THE EVENING BUT MAY
REBOUND LATE AS CLOUDS INCREASE WITH STRENGTHENING 850 MB WAA AND
ASSOCIATED 280K ISENTROPIC ASCENT. WITH THE MID LEVEL REMAINING
DRY...NO PCPN IS EXPECTED.
SAT...AS THE SFC HIGH SLOWLY BUILDS INTO THE ERN LAKES...SRLY WINDS
WILL BRING WARMER AIR INTO THE REGION WITH TEMPS CLIMBING SLIGHTLY
ABOVE NORMAL WITH MAX READINGS CLIMB TO AROUND 30 DESPITE THE
THICKENING CLOUDS.
SUN...AS A MID LEVEL TROUGH DEVELOPS ACROSS THE CENTRAL CONUS...THE
MODELS SUGGEST POTENTIAL FOR A WEAK SHORTWAVE AND AREA OF MORE
SUBSTANTIAL 290K ISENTROPIC LIFT THAT COULD PRODUCE SOME LIGHT SNOW.
THE DYNAMICS REMAIN WEAK ENOUGH TO SUPPORT ONLY SLIGHT CHANCE POPS.
CONTINUED WAA WILL NUDGE MAX TEMPS INTO THE LOWER 30S.
MON-WED...ALTHOUGH THERE IS GENERAL MODEL AGREEMENT THAT A MID LEVEL
TROUGH WILL DEEPEN OVER THE NORTHERN GREAT LAKES...THERE ARE
CONSIDERABLE DIFFERENCES IN THE DETAILS OF HOW THE SHORTWAVES DIVING
INTO THE TROUGH WILL INTERACT AND HOW THAT WILL INFLUENCE
THE POSITION/STRENGTH OF THE SFC FEATURES. SNOW CHANCES INCREASE
FROM MON INTO MON NIGHT AS THE INITIAL LOW MOVES THROUGH THE UPPER MS
VALLEY. ENOUGH WARM AIR MAY BE DRAWN NORTHWARD TO BRING POTENTIAL FOR
SOME RAIN INTO THE EAST HALF. THE PREFERRED/MORE CONSISTENT 00Z/12Z
ECMWF KEEP THE LOW AND WARMER AIR SLIGHTLY FARTHER TO THE
SOUTH...MINIMIZING CHANCES FOR RAIN. THE LARGER DISPARITIES DEVELOP
BY WED WITH THE HANDLING OF A STRONGER SHRTWV THAT WOULD SUPPORT
RAPID DEEPENING OF THE SFC LOW. THE 18Z/00Z GFS AND 00Z ECMWF HAVE
BACKED OFF FROM THE VERY STRONG LOW MOVING INTO THE CNTRL LAKE AND
THEN NORTHWARD TOWARD JAMES BAY AND HAVE SHIFTED THE STRONGER LOW
THROUGH THE NORTHEAST CONUS. HOWEVER...IT WOULD NOT BE SURPRISING TO
SEE THE MODELS REVERT BACK TO THE STRONGER LOW THROUGH LOWER MI. WITH
SO MUCH UNCERTAINTY AND HIGH ENSEMBLE/MODEL SPREAD...THE FCST
MAINTAINS HIGHER END SNOW CHANCES BUT WITH LESS EMPHASIS FOR NOW ON
THE POTENTIAL FOR HEAVY SNOW AND HIGH WINDS UNTIL FCST CONFIDENCE IS
HIGHER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 637 AM EST THU DEC 18 2014
HIGH PRESSURE JUST TO THE NORTH OF THE MINNESOTA ARROWHEAD WILL
CONTINUE TO ROTATE DRIER AIR SOUTH OVER THE AREA TODAY. SKIES
CLEARED YESTERDAY EVENING OVER THE KEWEENAW PENINSULA AND THEY WILL
STAY CLEAR THROUGHOUT THE DAY TODAY WITH LIGHT WINDS. AT
KIWD/KSAW...THE MVFR CLOUDS CONTINUE TO BE TRAPPED BELOW THE
INVERSION...BUT THE DRIER AIR HAS BEEN SEEN MAKING A DENT OVER THE
CLOUD COVER...ESPECIALLY TOWARDS KSAW. WHILE CONFIDENCE IS LOW ON
THE EXACT TIMING OF THE SCATTERING OUT OF THE CLOUDS...IT SHOULD BE
BY MID TO LATE MORNING. VFR CONDITIONS AND MAINLY LIGHT WINDS WILL
REMAIN FOR THE REST OF THE DAY AND MUCH OF THE NIGHT. THERE IS THE
POTENTIAL FOR SOME VERY SHALLOW FOG TO DEVELOP OVERNIGHT TONIGHT AT
THE TAF SITES...BUT THE CONFIDENCE IS TOO LOW TO SHOW A CATEGORY
DROP.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 403 AM EST THU DEC 18 2014
HIGH PRESSURE BUILDING INTO THE UPPER GREAT LAKES REGION TODAY AND
TONIGHT WILL DIMINISH THE NORTHERLY WINDS BELOW 15KTS. THE HIGH
WILL BEGIN TO SHIFT TO THE EAST OF THE REGION ON FRIDAY AND ALLOW
WINDS TO GRADUALLY TURN TO THE SOUTH THROUGH FRIDAY NIGHT. A NEARLY
STATIONARY TROUGH IN THE LEE OF THE NORTHERN ROCKIES THIS WEEKEND
WILL KEEP THE SOUTH TO SOUTHWESTERLY WINDS IN PLACE AND GENERALLY
UNDER 20KTS. THIS TROUGH WILL GIVE WAY TO A DEVELOPING LOW THAT
WILL MOVE INTO THE NORTHERN PLAINS SUNDAY NIGHT AND THE UPPER
MISSISSIPPI VALLEY ON MONDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
517 AM EST THU DEC 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM EST THU DEC 18 2014
AN UPPER RIDGE STRETCHING FROM MINNESOTA THROUGH NORTHWEST ONTARIO
WILL BE THE MAIN FEATURE CONTROLLING THE WEATHER OVER THE UPPER
GREAT LAKES REGION OVER THE NEXT 24 HOURS. BENEATH THIS UPPER
RIDGE...A 1029MB SURFACE HIGH SITS JUST TO THE NORTH OF THE
MINNESOTA WHILE THE SURFACE TROUGH THAT LED TO THE SNOW YESTERDAY
IS OVER NORTHERN LAKE MICHIGAN AND NORTHERN LOWER MICHIGAN AND
WEAKENING. NORTH-NORTHEASTERLY FLOW AROUND THIS HIGH HAS PULLED
DRIER AIR INTO THE UPPER GREAT LAKES REGION...LEADING TO CLEARING
SKIES THIS PAST EVENING OVER MUCH OF LAKE SUPERIOR. BUT MOISTURE
TRAPPED BELOW THE SUBSIDENCE INVERSION...AND COMBINED WITH UPSLOPE
FLOW...HAS LED TO LOW CLOUDS PERSISTING OVER A GOOD PORTION OF
UPPER MICHIGAN EARLY THIS MORNING. THERE ARE A COUPLE SPOTS WHERE
THE CLOUDS DID CLEAR OUT...GENERALLY OVER THE KEWEENAW PENINSULA
AND ALSO IT/S STARTING TO OVER THE EAST. WHERE SKIES CLEARED
OUT...3AM TEMPERATURES ARE IN THE SINGLE DIGITS ABOVE ZERO (6
DEGREES AT KCMX)...WHILE THE CLOUDS HAVE KEPT THE TEMPERATURES IN
THE UPPER TEENS AND LOWER 20S ELSEWHERE. STILL SEEING LIGHT
FLURRIES HERE AT OUR OFFICE AT 330AM...SO WILL CONTINUE TO MENTION
ISOLATED FLURRIES IN THE FORECAST FOR THE UPSLOPE LOCATIONS THROUGH
DAYBREAK.
WITH THE UPPER RIDGE AND SURFACE HIGH MOVING OVER THE AREA
TODAY...EXPECT CONTINUED QUIET CONDITIONS FOR THE SHORT TERM
PERIOD. THERE ARE TWO AREAS OF FOCUS IN THE SHORT TERM
PERIOD...FIRST THE LOW CLOUDS AND THEIR DIMINISHMENT AND THEN THE
POTENTIAL FOR SOME FREEZING FOG OVERNIGHT TONIGHT. FOR THE LOW
CLOUDS...KMQT VWP INDICATES CLOUD TOPS AROUND 2.5KFT...WHICH
MATCHES UP WELL WITH THE INVERSION INDICATED ON THE MODELS AT
900MB. THE BIG QUESTION IS WHEN WILL THEY DISSIPATE TODAY. AT
THIS TIME OF THE YEAR WITH THE LOW SUN ANGLE AND LIMITED
MIXING...THERE IS LITTLE DAY TIME HELP AND WILL NEED TO RELY ON THE
ADVECTION OF DRIER AIR INTO THE AREA. UNFORTUNATELY...THIS IS WHERE
THE MODELS TEND TO DIFFER. THE 00Z NAM HOLDS ONTO THE CLOUDS FOR
MUCH OF THE DAY AND EVEN THROUGH THE NIGHT TONIGHT...BUT THINK THAT
IS LARGELY TIED TO IT TRADITIONALLY OVER DOING LOW LEVEL MOISTURE.
THAT APPEARS TO THE CASE EARLY THIS MORNING...WHERE IT HAS THE LOW
CLOUDS JUST TO THE WEST OF JAMES BAY BEING MUCH FARTHER TO THE
SOUTH AND SUPPOSEDLY ENTERING NORTHERN LAKE SUPERIOR AT THIS TIME.
THE RECENT RAP (ALONG WITH THE HRRR) RUNS ALSO HOLD ONTO THE CLOUDS
FOR MUCH OF THE DAY BEFORE CLEARING THEM OUT THIS AFTERNOON...BUT IT
APPEARS TO HAVE THE LOW LEVEL MOISTURE FARTHER NORTH OVER LAKE
SUPERIOR THAN WHAT IS ACTUALLY OCCURRING. THE MORE OPTIMISTIC
RUNS...WHICH SEEM TO HAVE A BETTER HANDLE ON THE LOCATION OF THE
LOW CLOUDS ARE THE 00Z GFS/ECMWF. THEY HOLD ONTO THE LOW CLOUDS
OVER THE NORTH CENTRAL AND WEST FOR THE FIRST PART OF THE MORNING
AND THEN SCATTER THEM OUT THROUGH THE LATER PART OF THE MORNING AND
EARLY AFTERNOON. WILL FOLLOW THAT IDEA AT THIS POINT FOR THE CLOUD
COVER FORECAST FOR TODAY. MEANWHILE OVER THE EAST...THE ADVECTION
OF THE DRIER AIR AND LITTLE UPSLOPE HELP SHOULD ALLOW THE LOW
CLOUDS TO DISSIPATE DURING THE FIRST PART OF THE MORNING. THAT DRY
AIR HAS ALREADY SCATTERED THE CLOUDS OUT OVER LUCE COUNTY AND
STARTING TO SEE IT WORK INTO ALGER/SCHOOLCRAFT COUNTIES. AS FOR
HIGHS TODAY...EXPECT THEM TO BE IN THE MID-UPPER 20S OVER MUCH OF
THE AREA.
FOLLOWING THE IDEA OF THE CLOUDS DIMINISHING TODAY...WOULD EXPECT A
VERY GOOD RADIATIONAL COOLING NIGHT TONIGHT UNDER THE CENTER OF THE
HIGH. THUS...WILL CONTINUE THE IDEA OF GOING AT OR BELOW THE
COLDEST GUIDANCE. THE GEM MODELS USUALLY PERFORM WELL IN
RADIATIONAL COOLING NIGHTS AND THEY HAVE LOWS IN THE LOWER SINGLE
DIGITS WHERE THEY ARE NOT INDICATING CLOUDS (ALTHOUGH THE REGIONAL
GEM REDEVELOPS LOW CLOUDS OVER THE HIGHER TERRAIN OF THE NORTH
CENTRAL TONIGHT). THUS...HAVE LOWS IN THE SINGLE DIGITS ABOVE ZERO
TO AROUND ZERO OVER THE INTERIOR LOCATIONS. WITH KCMX DROPPING TO 6
DEGREES AT 3AM THIS MORNING...THAT SUPPORTS TO EXPECTATIONS FOR
TONIGHT. THIS EXPECTED DROP IN TEMPS WILL LEAD TO THE POTENTIAL FOR
PATCHY FREEZING FOG OR AT LEAST SOME SOLID FROST. WITH DEWPOINTS IN
THE MID-UPPER TEENS TODAY...TEMPS SHOULD EASILY DROP THROUGH THOSE
VALUES THIS EVENING. DEWPOINTS THIS PAST EVENING AT KCMX WERE
SIMILAR TO WHAT IS EXPECTED ACROSS THE REST OF THE AREA THIS
AFTERNOON. WITH THEIR QUICK TEMP DROP AND LIGHT WINDS...THEY HAVEN/T
EXPERIENCED ANY FOG AT THIS POINT...BUT THE ICE ACCRETION ALGORITHM
DID INDICATE SOME ICE ACCUMULATION. THIS IS LIKELY DUE TO THAT QUICK
DROP AND IN TURN SOME QUICK/HARD FROST ON THE SENSOR. IT WILL BE
INTERESTING TO SEE IF ANY VERY SHALLOW FOG DEVELOPS AT KCMX OVER
THE NEXT COUPLE HOURS...AS IT WILL FORESHADOW WHAT WILL OCCUR
TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 514 AM EST THU DEC 18 2014
FRIDAY...A DRY AIRMASS ASSOCIATED WITH THE DEPARTING AREA OF
HIGH PRESSURE WILL LEAVE PARTLY TO MOSTLY SUNNY SKIES ACROSS UPPER
MICHIGAN. HOWEVER...THERE IS SOME UNCERTAINTY WHETHER MOISTURE
BENEATH THE PROMINENT 925 MB INVERSION WILL LINGER ENOUGH FOR MOSTLY
CLOUDY SKIES...ESPECIALLY OVER THE WEST. EVEN WITH SOME
CLOUDS...TEMPS ARE EXPECTED TO CLIMB INTO THE UPPER 20S.
FRI NIGHT...TEMPS SHOULD DROP OFF QUICKLY IN THE EVENING BUT MAY
REBOUND LATE AS CLOUDS INCREASE WITH STRENGTHENING 850 MB WAA AND
ASSOCIATED 280K ISENTROPIC ASCENT. WITH THE MID LEVEL REMAINING
DRY...NO PCPN IS EXPECTED.
SAT...AS THE SFC HIGH SLOWLY BUILDS INTO THE ERN LAKES...SRLY WINDS
WILL BRING WARMER AIR INTO THE REGION WITH TEMPS CLIMBING SLIGHTLY
ABOVE NORMAL WITH MAX READINGS CLIMB TO AROUND 30 DESPITE THE
THICKENING CLOUDS.
SUN...AS A MID LEVEL TROUGH DEVELOPS ACROSS THE CENTRAL CONUS...THE
MODELS SUGGEST POTENTIAL FOR A WEAK SHORTWAVE AND AREA OF MORE
SUBSTANTIAL 290K ISENTROPIC LIFT THAT COULD PRODUCE SOME LIGHT SNOW.
THE DYNAMICS REMAIN WEAK ENOUGH TO SUPPORT ONLY SLIGHT CHANCE POPS.
CONTINUED WAA WILL NUDGE MAX TEMPS INTO THE LOWER 30S.
MON-WED...ALTHOUGH THERE IS GENERAL MODEL AGREEMENT THAT A MID LEVEL
TROUGH WILL DEEPEN OVER THE NORTHERN GREAT LAKES...THERE ARE
CONSIDERABLE DIFFERENCES IN THE DETAILS OF HOW THE SHORTWAVES DIVING
INTO THE TROUGH WILL INTERACT AND HOW THAT WILL INFLUENCE
THE POSITION/STRENGTH OF THE SFC FEATURES. SNOW CHANCES INCREASE
FROM MON INTO MON NIGHT AS THE INITIAL LOW MOVES THROUGH THE UPPER MS
VALLEY. ENOUGH WARM AIR MAY BE DRAWN NORTHWARD TO BRING POTENTIAL FOR
SOME RAIN INTO THE EAST HALF. THE PREFERRED/MORE CONSISTENT 00Z/12Z
ECMWF KEEP THE LOW AND WARMER AIR SLIGHTLY FARTHER TO THE
SOUTH...MINIMIZING CHANCES FOR RAIN. THE LARGER DISPARITIES DEVELOP
BY WED WITH THE HANDLING OF A STRONGER SHRTWV THAT WOULD SUPPORT
RAPID DEEPENING OF THE SFC LOW. THE 18Z/00Z GFS AND 00Z ECMWF HAVE
BACKED OFF FROM THE VERY STRONG LOW MOVING INTO THE CNTRL LAKE AND
THEN NORTHWARD TOWARD JAMES BAY AND HAVE SHIFTED THE STRONGER LOW
THROUGH THE NORTHEAST CONUS. HOWEVER...IT WOULD NOT BE SURPRISING TO
SEE THE MODELS REVERT BACK TO THE STRONGER LOW THROUGH LOWER MI. WITH
SO MUCH UNCERTAINTY AND HIGH ENSEMBLE/MODEL SPREAD...THE FCST
MAINTAINS HIGHER END SNOW CHANCES BUT WITH LESS EMPHASIS FOR NOW ON
THE POTENTIAL FOR HEAVY SNOW AND HIGH WINDS UNTIL FCST CONFIDENCE IS
HIGHER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1224 AM EST THU DEC 18 2014
SKIES HAVE ALREADY CLEARED OUT AT KCMX AS DRY AIR ARRIVES FROM THE
NORTH. LINGERING FLURRIES WILL END EARLY THIS MORNING AT KIWD AND
KSAW...BUT LOW MVFR CIGS SHOULD REMAIN AS MOISTURE IS TRAPPED BELOW
STRENGTHENING INVERSION. EXPECT SKIES TO GRADUALLY CLEAR AT BOTH
SITES BY THIS AFTERNOON DUE TO MIXING OUT OF THE SHALLOW MOIST
LAYER. RISK OF FREEZING FOG TONIGHT AT MAINLY KSAW AND POSSIBLY
KCMX. DID LEAVE OUT OF TAFS ATTM THOUGH AS GREATEST CHANCE OF VSBY
REDUCTION AND ICE DEPOSITION SHOULD NOT OCCUR UNTIL AFTER END OF TAF
PERIOD LATER ON THURSDAY NIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 403 AM EST THU DEC 18 2014
HIGH PRESSURE BUILDING INTO THE UPPER GREAT LAKES REGION TODAY AND
TONIGHT WILL DIMINISH THE NORTHERLY WINDS BELOW 15KTS. THE HIGH
WILL BEGIN TO SHIFT TO THE EAST OF THE REGION ON FRIDAY AND ALLOW
WINDS TO GRADUALLY TURN TO THE SOUTH THROUGH FRIDAY NIGHT. A NEARLY
STATIONARY TROUGH IN THE LEE OF THE NORTHERN ROCKIES THIS WEEKEND
WILL KEEP THE SOUTH TO SOUTHWESTERLY WINDS IN PLACE AND GENERALLY
UNDER 20KTS. THIS TROUGH WILL GIVE WAY TO A DEVELOPING LOW THAT
WILL MOVE INTO THE NORTHERN PLAINS SUNDAY NIGHT AND THE UPPER
MISSISSIPPI VALLEY ON MONDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...JLA
MARINE...SRF
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1001 AM CST THU DEC 18 2014
.UPDATE...
ISSUED AT 959 AM CST THU DEC 18 2014
CLOUD TRENDS THE MAIN ISSUE TODAY. AREA OF MID CLOUDS AND THEN
LOWER MVFR CLOUDS ADVANCING NORTHEAST EAST OF THE UPPER TROUGH
OVER WRN ND. THIS WILL CONTINUE TO SPREAD EAST INTO THIS AFTN.
ALSO GOT A FAST MOVING AREA OF LOWER STRATOCU MOVING NORTH-
NORTHWEST FROM WISCONSIN INTO NE-ECNTRL MN AND ITS HEADED TOWARD
OUR EASTERN COUNTIES SO INCREASED CLOUD COVER THERE. ALSO QUITE A
BIT OF FLURRIES IN THIS CLOUD AREA...SO MATCHED UP WITH WFO DLH
AND INCLUDED FLURRIES THIS AFTN IN THE FAR EASTERN FCST AREA. KEPT
FLURRIES IN FAR WEST BUT HAVENT SEEN ANY SIGNS OF PRECIP IN CNTRL
ND.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 314 AM CST THU DEC 18 2014
MAIN ISSUE TODAY WILL BE CLOUDS MOVING INTO THE WEST AND IF WE GET
ANY SNOW OF MENTION OR JUST FLURRIES.
A WEAK UPPER SHORTWAVE TROUGH IS SEEN ON WV LOOP ROTATING OVER THE
MT/ND BORDER...AND THAT FEATURE WILL MOVE INTO THE EASTERN DAKOTAS
TODAY. THIS WILL HELP BRING SOME FAIRLY WEAK SYNOPTIC LIFT INTO THE
REGION. THE SFC HIGH WILL MOVE OFF TO THE EAST...ALLOWING SOUTH
WINDS AND MORE MOISTURE TO MOVE BACK INTO THE AREA. THERE HAS BEEN
A DECENT BAND OF SNOW OVER CENTRAL ND...WHICH MATCHES PRETTY WELL
WHERE THE RAP HAS SOME Q VECTOR CONVERGENCE COINCIDING WITH
FRONTOGENESIS. THE RAP HAS THIS FEATURE WEAKENING SIGNIFICANTLY AS
IT MOVES EAST INTO OUR CWA LATER THIS MORNING...SO THINK A WELL
DEFINED BAND OF SNOW IS NOT TOO LIKELY. HOWEVER...SOME VERY LIGHT
SNOW IS NOT OUT OF THE QUESTION. INCLUDED SOME LOW POPS IN THE FAR
WEST WITH SOME FLURRIES GRADUALLY MOVING TOWARDS THE RED RIVER AS
CLOUDS CONTINUE TO INCREASE THROUGHOUT THE DAY IN THE WESTERN
COUNTIES. TEMPS TODAY SHOULD BE A BIT WARMER EVEN WITH CLOUDS AS
TEMPS UNDER THE CLOUDS ARE ALREADY CLOSE TO 20 DEGREES OUT WEST.
WILL CONTINUE TO KEEP HIGHS IN THE UPPER TEENS TO 20S.
TONIGHT...THE WEAK UPPER TROUGH CONTINUES OVER THE NORTHERN
PLAINS...WITH WARM AIR ADVECTION CONTINUING THROUGHOUT THE NIGHT.
CLOUDS WILL CONTINUE TO MOVE INTO THE AREA AND THAT ALONG WITH THE
SOUTH WINDS WILL PREVENT TEMPS FROM BOTTOMING OUT TONIGHT. TEMPS
SHOULD STAY MAINLY IN THE TEENS. THE WARM AIR ADVECTION WILL
CONTINUE INTO FRIDAY...ALLOWING TEMPS TO GET WELL INTO THE 20S TO
NEAR 30 IN THE SOUTH. MODELS CONTINUE TO SHOW SOME VERY LIGHT
PRECIP AS ISENTROPIC LIFT CONTINUES AND CONDENSATION PRESSURE
DEFICITS BECOME MORE FAVORABLE...MAINLY IN THE NORTHEASTERN
COUNTIES. WILL CONTINUE TO KEEP 20 POPS GOING FOR LIGHT SNOW...BUT
THINK THAT ANY ACCUMULATION WILL BE VERY LIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 314 AM CST THU DEC 18 2014
FRIDAY NIGHT THROUGH SATURDAY NIGHT...THE WEAK UPPER TROUGH
LINGERS OVER NORTHERN MN...AND THE NEXT SHORTWAVE TROUGH BEGINS TO
APPROACH FROM THE WEST. SOUTH WINDS WILL CONTINUE AND MOISTURE
SHOULD BE INCREASING. THERE CONTINUE TO BE SOME SIGNS OF PRECIP
MOVING IN WITH THAT SECOND SHORTWAVE LATE SATURDAY INTO SATURDAY
NIGHT. THERE IS A LOT OF VARIATION FROM THE NAM SHOWING UP TO A
TENTH OF AN INCH TO THE ECMWF HAVING HARDLY ANYTHING...SO KEPT
POPS LOW FOR NOW. THE SREF SHOWS SOME FZRA PROBABILITIES FOR
SATURDAY NIGHT...BUT THE TOP DOWN METHOD GIVES MOSTLY SNOW IN THE
NORTH WHERE POPS ARE LOCATED WITH THE WARM LAYER ALOFT STAYING
MOSTLY IN OUR SOUTH WHERE CURRENTLY WE ARE GOING DRY. WILL KEEP A
CLOSE EYE ON THE SITUATION. TEMPS WILL BE ABOVE AVERAGE WITH HIGHS
PUSHING 30 DEGREES AND LOWS STAYING IN THE TEENS TO EVEN LOW 20S.
FOR SUNDAY THROUGH WEDNESDAY...UPPER PATTERN SHIFTS A BIT BECOMING
MORE OF A NW FLOW REGIME WITH THE RIDGE AXIS OVER THE INTERMOUNTAIN
WEST. HOWEVER...THE MAIN JET ENERGY IS EXPECTED TO REMAIN WEST AND
SOUTH OF THE AREA. A FEW WAVES PUSHING ACROSS THE AREA WILL BRING
CHANCES FOR LIGHT PCPN...WHILE TEMPERATURES CONTINUE TO REMAIN NEAR
OR SLIGHTLY ABOVE NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 658 AM CST THU DEC 18 2014
ALL SITES ARE VFR FOR THE TIME BEING BUT CLOUDS ARE MAKING A RUN
FOR THE FORECAST AREA BOTH FROM THE WEST AND FROM THE EAST. CLOUDS
ENTERING THE KDVL AREA ARE MID LEVEL...SO VFR WILL REMAIN FOR A
BIT LONGER. THINK THAT THERE WILL BE SOME INCREASING MID CLOUDS
THROUGHOUT THE DAY AND THEN SOME MVFR CIGS MOVING IN LATE THIS
AFTERNOON AND EVENING. THE MODELS ARE NOT HANDLING THE STRATUS
MOVING NORTHWESTWARD THROUGH EASTERN MN...WHICH MAY IMPACT KBJI
LATER ON. BASED ON THE SPEED OF THE CLOUD DECK SOME MVFR CIGS
COULD ENTER KBJI AS SOON AS EARLY AFTERNOON. ALL TAF SITES SHOULD
BE MVFR OR EVEN IFR BY THE END OF THE PERIOD. SOME FLURRIES ARE
POSSIBLE BUT NOT WIDESPREAD OR EXPECTED TO BRING VIS DOWN FOR AN
EXTENDED PERIOD. LIGHT AND VARIABLE WINDS WILL STEADY OUT OF THE
SOUTHEAST AT UNDER 10 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...JR
LONG TERM...JR/HOPKINS
AVIATION...JR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
658 AM CST THU DEC 18 2014
.UPDATE...
ISSUED AT 658 AM CST THU DEC 18 2014
ADJUSTED CLOUDS A BIT AS THERE SEEMS TO BE A BIT FASTER CLOUDING
UP OF THE WESTERN CWA. A BAND OF RADAR RETURNS HAS ENTERED THE
WESTERN CWA BUT NOT MUCH AT THIS POINT HAS BEEN SEEN REACHING THE
GROUND. INCLUDED JUST A FLURRY MENTION BUT THINK THAT ACCUMULATING
SNOW CHANCES WILL BE MINIMAL.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 314 AM CST THU DEC 18 2014
MAIN ISSUE TODAY WILL BE CLOUDS MOVING INTO THE WEST AND IF WE GET
ANY SNOW OF MENTION OR JUST FLURRIES.
A WEAK UPPER SHORTWAVE TROUGH IS SEEN ON WV LOOP ROTATING OVER THE
MT/ND BORDER...AND THAT FEATURE WILL MOVE INTO THE EASTERN DAKOTAS
TODAY. THIS WILL HELP BRING SOME FAIRLY WEAK SYNOPTIC LIFT INTO THE
REGION. THE SFC HIGH WILL MOVE OFF TO THE EAST...ALLOWING SOUTH
WINDS AND MORE MOISTURE TO MOVE BACK INTO THE AREA. THERE HAS BEEN
A DECENT BAND OF SNOW OVER CENTRAL ND...WHICH MATCHES PRETTY WELL
WHERE THE RAP HAS SOME Q VECTOR CONVERGENCE COINCIDING WITH
FRONTOGENESIS. THE RAP HAS THIS FEATURE WEAKENING SIGNIFICANTLY AS
IT MOVES EAST INTO OUR CWA LATER THIS MORNING...SO THINK A WELL
DEFINED BAND OF SNOW IS NOT TOO LIKELY. HOWEVER...SOME VERY LIGHT
SNOW IS NOT OUT OF THE QUESTION. INCLUDED SOME LOW POPS IN THE FAR
WEST WITH SOME FLURRIES GRADUALLY MOVING TOWARDS THE RED RIVER AS
CLOUDS CONTINUE TO INCREASE THROUGHOUT THE DAY IN THE WESTERN
COUNTIES. TEMPS TODAY SHOULD BE A BIT WARMER EVEN WITH CLOUDS AS
TEMPS UNDER THE CLOUDS ARE ALREADY CLOSE TO 20 DEGREES OUT WEST.
WILL CONTINUE TO KEEP HIGHS IN THE UPPER TEENS TO 20S.
TONIGHT...THE WEAK UPPER TROUGH CONTINUES OVER THE NORTHERN
PLAINS...WITH WARM AIR ADVECTION CONTINUING THROUGHOUT THE NIGHT.
CLOUDS WILL CONTINUE TO MOVE INTO THE AREA AND THAT ALONG WITH THE
SOUTH WINDS WILL PREVENT TEMPS FROM BOTTOMING OUT TONIGHT. TEMPS
SHOULD STAY MAINLY IN THE TEENS. THE WARM AIR ADVECTION WILL
CONTINUE INTO FRIDAY...ALLOWING TEMPS TO GET WELL INTO THE 20S TO
NEAR 30 IN THE SOUTH. MODELS CONTINUE TO SHOW SOME VERY LIGHT
PRECIP AS ISENTROPIC LIFT CONTINUES AND CONDENSATION PRESSURE
DEFICITS BECOME MORE FAVORABLE...MAINLY IN THE NORTHEASTERN
COUNTIES. WILL CONTINUE TO KEEP 20 POPS GOING FOR LIGHT SNOW...BUT
THINK THAT ANY ACCUMULATION WILL BE VERY LIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 314 AM CST THU DEC 18 2014
FRIDAY NIGHT THROUGH SATURDAY NIGHT...THE WEAK UPPER TROUGH
LINGERS OVER NORTHERN MN...AND THE NEXT SHORTWAVE TROUGH BEGINS TO
APPROACH FROM THE WEST. SOUTH WINDS WILL CONTINUE AND MOISTURE
SHOULD BE INCREASING. THERE CONTINUE TO BE SOME SIGNS OF PRECIP
MOVING IN WITH THAT SECOND SHORTWAVE LATE SATURDAY INTO SATURDAY
NIGHT. THERE IS A LOT OF VARIATION FROM THE NAM SHOWING UP TO A
TENTH OF AN INCH TO THE ECMWF HAVING HARDLY ANYTHING...SO KEPT
POPS LOW FOR NOW. THE SREF SHOWS SOME FZRA PROBABILITIES FOR
SATURDAY NIGHT...BUT THE TOP DOWN METHOD GIVES MOSTLY SNOW IN THE
NORTH WHERE POPS ARE LOCATED WITH THE WARM LAYER ALOFT STAYING
MOSTLY IN OUR SOUTH WHERE CURRENTLY WE ARE GOING DRY. WILL KEEP A
CLOSE EYE ON THE SITUATION. TEMPS WILL BE ABOVE AVERAGE WITH HIGHS
PUSHING 30 DEGREES AND LOWS STAYING IN THE TEENS TO EVEN LOW 20S.
FOR SUNDAY THROUGH WEDNESDAY...UPPER PATTERN SHIFTS A BIT BECOMING
MORE OF A NW FLOW REGIME WITH THE RIDGE AXIS OVER THE INTERMOUNTAIN
WEST. HOWEVER...THE MAIN JET ENERGY IS EXPECTED TO REMAIN WEST AND
SOUTH OF THE AREA. A FEW WAVES PUSHING ACROSS THE AREA WILL BRING
CHANCES FOR LIGHT PCPN...WHILE TEMPERATURES CONTINUE TO REMAIN NEAR
OR SLIGHTLY ABOVE NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 658 AM CST THU DEC 18 2014
ALL SITES ARE VFR FOR THE TIME BEING BUT CLOUDS ARE MAKING A RUN
FOR THE FORECAST AREA BOTH FROM THE WEST AND FROM THE EAST. CLOUDS
ENTERING THE KDVL AREA ARE MID LEVEL...SO VFR WILL REMAIN FOR A
BIT LONGER. THINK THAT THERE WILL BE SOME INCREASING MID CLOUDS
THROUGHOUT THE DAY AND THEN SOME MVFR CIGS MOVING IN LATE THIS
AFTERNOON AND EVENING. THE MODELS ARE NOT HANDLING THE STRATUS
MOVING NORTHWESTWARD THROUGH EASTERN MN...WHICH MAY IMPACT KBJI
LATER ON. BASED ON THE SPEED OF THE CLOUD DECK SOME MVFR CIGS
COULD ENTER KBJI AS SOON AS EARLY AFTERNOON. ALL TAF SITES SHOULD
BE MVFR OR EVEN IFR BY THE END OF THE PERIOD. SOME FLURRIES ARE
POSSIBLE BUT NOT WIDESPREAD OR EXPECTED TO BRING VIS DOWN FOR AN
EXTENDED PERIOD. LIGHT AND VARIABLE WINDS WILL STEADY OUT OF THE
SOUTHEAST AT UNDER 10 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...JR
LONG TERM...JR/HOPKINS
AVIATION...JR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1021 AM EST THU DEC 18 2014
.SYNOPSIS...
A WEAKENING UPPER LEVEL DISTURBANCE MOVING THROUGH THE OHIO VALLEY
WILL LEAD TO A FEW SNOW FLURRIES THIS AFTERNOON INTO THIS EVENING.
WEAK SURFACE HIGH PRESSURE WILL THEN PUSH SLOWLY EAST ACROSS THE
REGION THROUGH THE WEEKEND...LEADING TO PRIMARILY DRY CONDITIONS
AND NEAR NORMAL TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MID LEVEL SHORTWAVE TO TRACK FROM THE CENTRAL PLAINS EAST ACROSS
THE OHIO VALLEY TODAY. GOOD DEAL OF LOW CLOUDS REMAIN IN PLACE
THIS MORNING. 12Z ILN SOUNDING SHOWS THIS SHALLOW MOISTURE TRAPPED
BELOW AN INVERSION AROUND 880 MB. EVEN WITH SOME EROSION OF THESE
LOW CLOUDS...MID LEVEL CLOUDS ASSOCIATED WITH THE AFOREMENTIONED
S/W WILL OVERSPREAD THE REGION. THIS S/W WILL DAMPEN AND WEAKEN
AS IT PASSES THRU THE OHIO VALLEY. NUMERICAL MODELS SUGGEST
WEAK LIFT IN THE MID LEVELS DEVELOPING EARLY AFTERNOON.
EXPECT THIS TO RESULT IN SOME FLURRIES OR EVEN SOME ISOLD SNOW
SHOWER ACTIVITY. HAVE CONTINUED WITH JUST A CHANCE OF FLURRIES
THIS AFTERNOON. GIVEN THE COMBINATION OF THE CLOUDS AND MAINLY
NEUTRAL LOW LEVEL TEMPERATURE ADVECTION THROUGH THE DAY...
EXPECT A SMALL DIURNAL RISE TO READINGS TODAY. HAVE HIGHS FROM THE
LOWER 30S NORTH TO THE MID 30S SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
WE COULD SEE A FEW FLURRIES LINGER INTO THIS EVENING...BUT FOR THE
MOST PART EXPECT DRY CONDITIONS TONIGHT THROUGH FRIDAY AS A WEAK
AREA OF HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES REGION. THE
MODELS CONTINUE TO TREND FARTHER SOUTH WITH THE LOW PRESSURE
SYSTEM MOVING THROUGH THE SOUTHEASTERN UNITED STATES FRIDAY NIGHT
INTO SATURDAY. WITH THE BETTER FORCING GENERALLY REMAINING TO OUR
SOUTHEAST...WILL TRIM BACK POPS AND JUST ALLOW FOR A TOKEN SLIGHT
CHANCE INTO OUR FAR SOUTHEAST THROUGH THE DAY ON SATURDAY. WITH
THIS FARTHER SOUTH SOLUTION...WE WOULD BE COLD ENOUGH FOR ANY PCPN
TO BE ALL SNOW. FAIRLY SEASONABLE TEMPERATURES ARE EXPECTED THROUGH THE
END OF THE WEEK...WITH HIGHS BOTH FRIDAY AND SATURDAY IN THE MID TO
UPPER 30S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRESSURE AND A COOL AIRMASS SHOULD ALLOW DRY WEATHER ON
SUNDAY. LIGHT PRECIP WILL BE POSSIBLE MONDAY EXTENDING FROM A
TROUGH ALONG THE EAST COAST.
WE MAY BEGIN TO FEEL THE EFFECTS OF A POWERFUL LOW PRESSURE SYSTEM
ON TUESDAY. HAVE LESS THAN AVERAGE AMOUNT OF CONFIDENCE DUE TO MODEL
DIFFERENCES FROM RUN TO RUN. AT THIS POINT IT APPEARS THE LOW WILL
DEVELOP OVER THE SOUTHERN PLAINS ON TUESDAY...BEFORE LIFTING THROUGH
OHIO TO THE GREAT LAKES ON WEDNESDAY. THE LOW MAY FEATURE A VERY
TIGHT PRESSURE GRADIENT SURROUNDING ITS DEEP CENTER...PRODUCING
STRONG WINDS. COPIOUS MOISTURE FEEDING FROM THE TROPICS AND FROM THE
ATLANTIC OCEAN COULD ADVECT AROUND THE LOW. CURRENT TEMPERATURE
FORECAST ALLOWS RAIN TUESDAY INTO WEDNESDAY...CHANGING TO SNOW LATER
WEDNESDAY AS COLDER AIR WRAPS IN BEHIND THE LOW.
TEMPERATURES WILL BE RELATIVELY CLOSE TO NORMAL FOR THE MOST PART.
HIGHS WILL BE A COUPLE DEGREES WARMER FOR SUNDAY AND MONDAY UNDER
NEUTRAL TO WEAK WARM ADVECTION. READINGS ON TUESDAY AND WEDNESDAY
WILL BE DEPENDENT ON THE POSITION OF THE ANTICIPATED STRONG LOW.
WARM ADVECTION AHEAD OF THE LOW COULD BRING HIGHS UP INTO THE MID
40S ON TUESDAY...OR EVEN HIGHER IF THE WARMER MEX GUIDANCE
VERIFIES. HIGHS COULD SLIP TO AROUND 40 ON WEDNESDAY IN COLD
ADVECTION BEHIND THE LOW.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
A PERSISTENT MVFR CLOUD DECK IS LIKELY TO REMAIN IN PLACE ACROSS
THE TAF SITES INTO THE AFTERNOON. AT THAT TIME THE DECK SHOULD
BREAK...BECOMING VFR....AS A WEAK UPPER LEVEL SYSTEM APPROACHES
THE AREA WITH ITS ASSOCIATED MID AND HIGH CLOUDS. AFTER THIS THERE
CONTINUES TO BE MAJOR DISAGREEMENT IN THE NUMERICAL GUIDANCE. SVRL
MODELS BRING MVFR CIGS BACK INTO THE AREA THIS EVENING WHILE
OTHERS CONTINUE WITH A DECK OF VFR CIGS BTWN FL050 AND 070. HAVE
CHOSEN TO GO WITH THE RAP SOLUTION WHICH SEEMS TO HAVE
SOMEWHAT...ALTHOUGH NOT PERFECT HANDLE ON THE SITUATION. WHILE
MOISTURE WITH THIS NEXT SYSTEM WILL BE LACKING IN TERMS OF
PCPN...FLURRIES ARE EXPECTED THIS AFTERNOON AND EVENING. SINCE NO
VSBY RESTRICTIONS ARE EXPECTED AND THE TIMING DURING THIS PERIOD
WILL BE VARIABLE HAVE NOT INCLUDED THIS MENTION IN THE FCST.
W WINDS OF UNDER 10 KNOTS ARE EXPECTED THROUGH THE FCST PERIOD.
OUTLOOK...MVFR CEILINGS MAY CONTINUE INTO FRIDAY. MVFR CEILINGS
AND VISIBILITIES ARE POSSIBLE ON SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL/AR
SHORT TERM...JGL
LONG TERM...CONIGLIO
AVIATION...HAYDU
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
659 AM EST THU DEC 18 2014
.SYNOPSIS...
A WEAKENING UPPER LEVEL DISTURBANCE MOVING THROUGH THE OHIO VALLEY
WILL LEAD TO A FEW SNOW FLURRIES THIS AFTERNOON INTO THIS EVENING.
WEAK SURFACE HIGH PRESSURE WILL THEN PUSH SLOWLY EAST ACROSS THE
REGION THROUGH THE WEEKEND...LEADING TO PRIMARILY DRY CONDITIONS
AND NEAR NORMAL TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PLENTY OF LOW CLOUDS REMAIN IN PLACE ACROSS THE AREA EARLY THIS
MORNING...ALTHOUGH WE ARE SEEING PERHAPS A BIT OF EROSION IN THESE JUST
OFF TO OUR SOUTHWEST. THIS IS IN THE AREA OF SOME ADVANCING MID
LEVEL MOISTURE THAT WILL WORK EAST ACROSS OUR AREA LATER THIS
MORNING AND INTO THIS AFTERNOON IN ASSOCIATION WITH A WEAKENING
MID LEVEL SHORT WAVE. AS A RESULT...WOULD EXPECT ANY DISSIPATION
IN THE LOWER LEVEL CLOUDS TO BE OVERCOME BY THE MID LEVEL
CLOUDS...RESULTING IN CLOUDY SKIES THROUGH THE DAY. MODELS ARE
SUGGESTING SOME WEAK LIFT AT AND ABOVE 700 MB DEVELOPING THROUGH
EARLY AFTERNOON AND EXPECT THIS TO RESULT IN SOME FLURRY OR
POSSIBLY EVEN SOME SNOW SHOWER ACTIVITY THIS AFTERNOON. THERE IS
ACTUALLY A PERIOD FROM ABOUT 18Z TO 21Z THIS AFTERNOON WHERE THE
DENDRITIC GROWTH ZONE IS MAXIMIZED IN THE AREA OF BEST LIFT
ACROSS PARTS OF OUR SOUTHERN FA. HOWEVER...GIVEN THAT THE MOISTURE
IS PRETTY LIMITED AND RATHER DRY BETWEEN ABOUT 950 MB AND 700
MB...WILL CONTINUE WITH JUST A CHANCE OF FLURRIES THIS AFTERNOON.
GIVEN THE COMBINATION OF THE CLOUDS AND MAINLY NEUTRAL LOW LEVEL
TEMPERATURE ADVECTION THROUGH THE DAY...ONLY EXPECT A FEW DEGREE
BUMP UP IN TEMPERATURES THROUGH THIS AFTERNOON WITH HIGHS
GENERALLY IN THE LOW TO POSSIBLY MID 30S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
WE COULD SEE A FEW FLURRIES LINGER INTO THIS EVENING...BUT FOR THE
MOST PART EXPECT DRY CONDITIONS TONIGHT THROUGH FRIDAY AS A WEAK
AREA OF HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES REGION. THE
MODELS CONTINUE TO TREND FARTHER SOUTH WITH THE LOW PRESSURE
SYSTEM MOVING THROUGH THE SOUTHEASTERN UNITED STATES FRIDAY NIGHT
INTO SATURDAY. WITH THE BETTER FORCING GENERALLY REMAINING TO OUR
SOUTHEAST...WILL TRIM BACK POPS AND JUST ALLOW FOR A TOKEN SLIGHT
CHANCE INTO OUR FAR SOUTHEAST THROUGH THE DAY ON SATURDAY. WITH
THIS FARTHER SOUTH SOLUTION...WE WOULD BE COLD ENOUGH FOR ANY PCPN
TO BE ALL SNOW. FAIRLY SEASONABLE TEMPERATURES ARE EXPECTED THROUGH THE
END OF THE WEEK...WITH HIGHS BOTH FRIDAY AND SATURDAY IN THE MID TO
UPPER 30S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRESSURE AND A COOL AIRMASS SHOULD ALLOW DRY WEATHER ON
SUNDAY. LIGHT PRECIP WILL BE POSSIBLE MONDAY EXTENDING FROM A
TROUGH ALONG THE EAST COAST.
WE MAY BEGIN TO FEEL THE EFFECTS OF A POWERFUL LOW PRESSURE SYSTEM
ON TUESDAY. HAVE LESS THAN AVERAGE AMOUNT OF CONFIDENCE DUE TO MODEL
DIFFERENCES FROM RUN TO RUN. AT THIS POINT IT APPEARS THE LOW WILL
DEVELOP OVER THE SOUTHERN PLAINS ON TUESDAY...BEFORE LIFTING THROUGH
OHIO TO THE GREAT LAKES ON WEDNESDAY. THE LOW MAY FEATURE A VERY
TIGHT PRESSURE GRADIENT SURROUNDING ITS DEEP CENTER...PRODUCING
STRONG WINDS. COPIOUS MOISTURE FEEDING FROM THE TROPICS AND FROM THE
ATLANTIC OCEAN COULD ADVECT AROUND THE LOW. CURRENT TEMPERATURE
FORECAST ALLOWS RAIN TUESDAY INTO WEDNESDAY...CHANGING TO SNOW LATER
WEDNESDAY AS COLDER AIR WRAPS IN BEHIND THE LOW.
TEMPERATURES WILL BE RELATIVELY CLOSE TO NORMAL FOR THE MOST PART.
HIGHS WILL BE A COUPLE DEGREES WARMER FOR SUNDAY AND MONDAY UNDER
NEUTRAL TO WEAK WARM ADVECTION. READINGS ON TUESDAY AND WEDNESDAY
WILL BE DEPENDENT ON THE POSITION OF THE ANTICIPATED STRONG LOW.
WARM ADVECTION AHEAD OF THE LOW COULD BRING HIGHS UP INTO THE MID
40S ON TUESDAY...OR EVEN HIGHER IF THE WARMER MEX GUIDANCE
VERIFIES. HIGHS COULD SLIP TO AROUND 40 ON WEDNESDAY IN COLD
ADVECTION BEHIND THE LOW.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
A PERSISTENT MVFR CLOUD DECK IS LIKELY TO REMAIN IN PLACE ACROSS
THE TAF SITES INTO THE AFTERNOON. AT THAT TIME THE DECK SHOULD
BREAK...BECOMING VFR....AS A WEAK UPPER LEVEL SYSTEM APPROACHES
THE AREA WITH ITS ASSOCIATED MID AND HIGH CLOUDS. AFTER THIS THERE
CONTINUES TO BE MAJOR DISAGREEMENT IN THE NUMERICAL GUIDANCE. SVRL
MODELS BRING MVFR CIGS BACK INTO THE AREA THIS EVENING WHILE
OTHERS CONTINUE WITH A DECK OF VFR CIGS BTWN FL050 AND 070. HAVE
CHOSEN TO GO WITH THE RAP SOLUTION WHICH SEEMS TO HAVE
SOMEWHAT...ALTHOUGH NOT PERFECT HANDLE ON THE SITUATION. WHILE
MOISTURE WITH THIS NEXT SYSTEM WILL BE LACKING IN TERMS OF
PCPN...FLURRIES ARE EXPECTED THIS AFTERNOON AND EVENING. SINCE NO
VSBY RESTRICTIONS ARE EXPECTED AND THE TIMING DURING THIS PERIOD
WILL BE VARIABLE HAVE NOT INCLUDED THIS MENTION IN THE FCST.
W WINDS OF UNDER 10 KNOTS ARE EXPECTED THROUGH THE FCST PERIOD.
OUTLOOK...MVFR CEILINGS MAY CONTINUE INTO FRIDAY. MVFR CEILINGS
AND VISIBILITIES ARE POSSIBLE ON SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...CONIGLIO
AVIATION...HAYDU
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
506 AM CST THU DEC 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 311 AM CST THU DEC 18 2014
PESKY UPPER TROUGH STILL LINGERS OVER THE GREAT LAKES WITH THE
LAST LOBE OF SHORT WAVE ENERGY HANGING BACK ACROSS LAKE SUPERIOR.
LOW CLOUDS ASSOCIATED WITH IT STILL COVER THE BULK OF WI...BUT ARE
STARTING TO SHOW SOME SIGNS OF BREAKING UP. MEANWHILE...SATELLITE
WATER VAPOR IMAGERY SHOWS A NICE CIRCULATION ENTERING THE WESTERN
DAKOTAS. VERY LITTLE MOISTURE WITH IT SO PRIMARILY RESULTING IN
CLOUD GENERATION. FINALLY...ANOTHER WEAK SHORT WAVE TROUGH WAS
TRAVERSING THE LOWER MISSISSIPPI RIVER VALLEY AND HEADING TOWARD
TENNESSEE. SOME PEEKS AT THE SUN ANTICIPATED TODAY WITH THE AREA
BETWEEN SYSTEMS...BUT WITH THE LOW ADVANCING ACROSS THE DAKOTAS
EXPECT MORE CLOUD TO INVADE. WITH ALL THE CLOUDS...KEPT DIURNAL
TEMPERATURE SWING SMALL.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 311 AM CST THU DEC 18 2014
MEDIUM RANGE FORECAST MODELS BEGINNING TO COME INTO BETTER
AGREEMENT WITH THE EXPECTED PATTERN FOR THE UPCOMING HOLIDAY WEEK.
BLOCKED PATTERN WILL EVOLVE BRIEFLY INTO ZONAL FOR THE WEEKEND
BEFORE CONTINUING ON TO FAVOR A DEEP LONG WAVE TROUGH OVER THE
CENTRAL CONUS BY EARLY NEXT WEEK...WITH A LARGE RIDGE SETTING UP
JUST OFF THE CALIFORNIA COAST. ENERGY DROPPING INTO THE BACK SIDE
OF THE TROUGH RESULTS IN THE DEVELOPMENT OF A CLOSED LOW OVER
MN/IA AREA BY MONDAY...WHICH THEN STALLS AND DEEPENS OVER THE
GREAT LAKES THROUGH MID WEEK. THIS WAS HINTED AT IN PREVIOUS
RUNS...BUT IS NOW LOOKING MORE AND MORE LIKELY WITH THE MODELS
GENERALLY SETTLING IN ON A VERY SIMILAR SOLUTION.
AS THE TROUGH BEGINS TO DEVELOP ON SATURDAY...INCREASING ADVECTION
OF WARM AND MOIST AIR BEGINS. FORECAST SOUNDINGS SUGGEST BROAD
WEAK LIFT WITH THE BOUNDARY LAYER BECOMING SATURATED OR NEARLY SO
LATE SATURDAY INTO SUNDAY. MODELS TRENDING TOWARD BETTER CHANCES
FOR PRECIPITATION...AND WITH THE TEMPERATURE REGIME STILL ON THE
COOL SIDE OF THE FREEZING MARK...FREEZING DRIZZLE APPEARS TO BE A
POSSIBILITY. ADDED THIS SATURDAY NIGHT...TRENDING TOWARD A
RAIN/SNOW MIX AS WE MOVE INTO THE DAY SUNDAY. PERSONS WITH TRAVEL
PLANS WILL WANT TO BE COGNIZANT OF THIS. BY MONDAY...SURFACE LOW
DEVELOPS AND MAIN FORCING OF THE DEVELOPING CLOSED LOW BEGINS TO
IMPACT THE FORECAST AREA. BOOSTED RAIN/SNOW CHANCES INTO THE
LIKELY CATEGORY FOR MONDAY AS A RESULT. THE AREA GETS ON THE COLD
SIDE OF THE SYSTEM BY TUESDAY WITH NORTHWEST WINDS USHERING COLD
AIR BACK INTO THE REGION. EXPECT PERIODS OF LIGHT SNOW OFF AND ON
THROUGH WEDNESDAY. WHILE IT DOES NOT APPEAR THAT LARGE QUANTITIES
OF SNOW WILL FALL...IT IS LOOKING MORE AND MORE LIKELY THAT WE
WILL SEE AT LEAST SOME LIGHT SNOW COVER BY CHRISTMAS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 506 AM CST THU DEC 18 2014
EXPANSIVE AREA OF MVFR CEILINGS REMAINS OVER MUCH OF WISCONSIN
EARLY THIS MORNING. SATELLITE INDICATES THIS HAS NOT BEEN MOVING
MUCH IF AT ALL AND DOUBTFUL THAT IT WILL EXPAND WESTWARD INTO
KRST THIS MORNING GIVEN THE LIGHT FLOW FROM THE LOW LEVEL RIDGE
AXIS OVER THE AREA. LOOKING AT THE 18.09Z RAP AND 18.06Z NAM...NOT
REALLY EXPECTING MUCH MOVEMENT OF THIS CLOUD DECK THROUGH THE
ENTIRE PERIOD SO WILL KEEP THE MVFR CEILING IN PLACE FOR KLSE. AT
KRST...THERE SHOULD BE A MID LEVEL VFR CEILING IN PLACE TO START
THE PERIOD WITH CLOUDS FROM THE STORM SYSTEM WELL SOUTH OF THE
AREA. ONCE THESE MOVE OUT...BOTH THE RAP AND NAM SUGGEST THE MVFR
CEILINGS WILL REDEVELOP AND WILL SHOW THIS HAPPENING AROUND 18Z
AND THEN PERSISTING THROUGH THE NIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...MW
LONG TERM...MW
AVIATION...04
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1228 PM EST THU DEC 18 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 252 AM EST THU DEC 18 2014
HIGH PRESSURE IS EXPECTED ACROSS THE AREA THROUGH THE END OF THE
WEEK. THE NORTHERN FRINGES OF A LOW PRESSURE SYSTEM PASSING THROUGH
THE GULF COAST STATES MAY AFFECT PARTS OF THE AREA BY THE END OF
WEEK. A SIGNIFICANT LOW PRESSURE SYSTEM MAY MOVE INTO THE AREA BY
THE EARLY TO MIDDLE PARTS OF NEXT WEEK.
&&
.NEAR TERM /THIS AFTERNOON/...
ISSUED AT 956 AM EST THU DEC 18 2014
SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWS HIGH PRESSURE IN PLACE
OVER THE UPPER MIDWEST AND THE OHIO VALLEY. RADAR RETURNS SHOW
ECHO ALOFT OVE MUCH OF CENTRAL ILLINOUIS...HOWEVER SURFACE OBS
ONLY REPORT SN FALLING ACROSS WEST CENTRAL ILLINOIS. HRRR TENDS TO
KEEP THE ONGOING PRECIP SOUTH OF CENTRAL INDIANA AND WANES THE
ONGOING PRECIP OVER WESTERN ILLINOIS. ATTM...THE HRRR DOESN/T
APPEAR HANDLE THE ONGOING SITUTAION WELL. GFS 285K ISENTROPIC
SURFACE SHOWS GOOD UPGLIDE ACROSS MISSOURI...HELPING THE ONGOING
SNOW THERE. THIS FEAUTRE HOWEVER DOES NOT TRANSLATE WELL TO
CENTRAL INDIANA AS MODELS SUGGEST THE ISENTROPIC LIFT FAILS TO
REACH INDIANA. TIME HEIGHT SECTIONS CONTINUE TO SUGGEST GOOD MID
AND LOWER LEVEL MOISTURE AVAILABLE BETWEEN 18Z AND 00Z. CONFIDNECE
REMAINS LOW IN THIS EVENT...BUT WILL MONITOR CLOSELY. FOR NOW HAVE
ADDED SLIGHT CHC POPS TO MAINLY THE SOUTHERN PARTS OF THE FORECAST
AREA...WITH FLURRIES ELSEWHERE. WILL BE QUICK TO UPDATE SHOULD
ECHOS OVER ILLINOIS HOLD TOGETHER AND PRECIP BEGINS TO REACH THE
GROUND.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 252 AM EST THU DEC 18 2014
MODEL DATA SUGGEST THERE MAY STILL SOME REMNANT ENERGY MOVING
THROUGH THE AREA THIS EVENING ASSOCIATED WITH TODAY/S
DISTURBANCE...SO WILL EXTEND THE FLURRY MENTION INTO THE EVENING
HOURS TONIGHT.
OTHERWISE...A SPLIT FLOW IS EXPECTED TO DEVELOP BY THE END OF THE
WEEK AS THE UPPER BLOCK OVER SOUTHERN CANADA BREAKS DOWN. A SOUTHERN
STREAM DISTURBANCE IS EXPECTED TO SCOOT ALONG THE GULF COAST
STATES...WHILE A DRIER NORTHERN STREAM SYSTEM DIGS INTO THE GREAT
LAKES BY SATURDAY. OPERATIONAL GUIDANCE IS IN PRETTY GOOD AGREEMENT
IN KEEPING THE MAIN PRECIPITATION THREAT TIED UP IN THE SOUTHERN
STREAM AND WELL SOUTH OF THE LOCAL AREA. THERE ARE SOME ENSEMBLES
THAT DRAW ENOUGH MOISTURE NORTH FOR A THREAT FOR LIGHT SNOW AND
MINOR ACCUMULATIONS OVER THE SOUTHERN/SOUTHEASTERN ZONES LATE FRIDAY
NIGHT INTO SATURDAY. TO COVER THIS POSSIBILITY...WILL KEEP SOME
CHANCE POPS GOING FOR LIGHT SNOW DURING THOSE PERIODS OVER ABOUT THE
SOUTHEAST HALF OF THE FORECAST AREA.
GIVEN THE DEGREE OF CLOUD COVER EXPECTED OVER THE NEXT COUPLE OF
DAYS...WILL CONTINUE TO NARROW THE DIURNAL RANGE OF THE GFS MOS
TEMPERATURE GUIDANCE THROUGH THE PERIOD.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 340 AM EST THU DEC 18 2014
EXTENDED MODELS AND ENSEMBLES AGREE THAT STRONG PACIFIC JET...ARCING
OVER A HIGH AMPLITUDE WEST COAST UPPER RIDGE...WILL DIVE SOUTHEAST
OVER THE CENTRAL UNITED STATES DURING THE EARLY AND MIDDLE PART OF
NEXT WEEK RESULTING IN AN UPPER TROUGH CLOSING INTO AN UPPER LOW AND
INTENSIFYING INTO A VERY STRONG SYSTEM BEFORE IT MOVES INTO
SOUTHEASTERN CANADA ON CHRISTMAS. MODELS WERE NOT TOO FAR OFF
REGARDING STRENGTH AND TIMING OF THIS SYSTEM...SO A BLEND OF THE
FURTHER NORTH 00Z GFS AND FURTHER SOUTH 12Z ECMWF LOOKS GOOD.
00Z MODELS ARE SHOWING AN UPPER TROUGH OVER SOUTHEASTERN SOUTH
DAKOTA OR NORTHWESTERN IOWA AT 00Z TUESDAY WITH BROAD AREA OF UPPER
DIFFLUENT FLOW ALOFT OVER THE OHIO VALLEY AND GREAT LAKES.
MEANWHILE...LOW LEVEL FLOW WILL BE SOUTHERLY BY MONDAY AND OPEN THE
OHIO VALLEY AND GREAT LAKES TO THE GULF RESULTING IN DEEPENING
MOISTURE TO GO ALONG WITH THE UPPER FORCING. THIS WILL BRING RAIN TO
THE AREA BY MONDAY AS WELL AS ABOVE NORMAL TEMPERATURES. THE WARMER
TEMPERATURES AND RAIN WILL BE SHORT-LIVED...HOWEVER AS COLDER AIR
RUSHES IN FROM THE NORTHWEST ON THE BACK END OF THE SYSTEM LATE
TUESDAY OR TUESDAY NIGHT. ALONG WITH THE COLDER AIR...UPPER IMPULSES
WILL MOVE ACROSS THE AREA IN THE CYCLONIC FLOW IN THE WAKE OF THE
DEPARTING STACKED LOW THAT SHOULD MOVE INTO QUEBEC EARLY CHRISTMAS.
THIS SHOULD GENERATE SOME SNOW WITH LIGHT ACCUMULATION POSSIBLE BY
CHRISTMAS EVE.
00Z GFS ENSEMBLE MOS TEMPERATURES LOOK TOO WARM THIS WEEKEND.
STRONGLY PREFER THE COOLER 00Z DECEMBER 17 EUROPEAN ENSEMBLE MEAN
TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 18/1800Z TAF ISSUANCE/...
ISSUED AT 1208 PM EST THU DEC 18 2014
FLIGHT CONDITIONS WILL HOVER RIGHT AROUND THE MVFR/VFR MARK INTO
THE NIGHT. HOWEVER...TIME CROSS SECTIONS ARE LEANING TOWARD DRIER
CONDITIONS AT ALL LEVELS EARLY TOMORROW MORNING. SO...ANTICIPATE
SCATTERING SOME TIME BETWEEN FRI 09-15Z...WHICH IS REFLECTED IN
TAFS. AT THAT POINT...VFR SHOULD BE THE PREVAILING FLIGHT CATEGORY
THROUGH THE REMAINDER OF TAF PERIOD. NORTHWEST WINDS WILL VEER
SLIGHTLY TO THE NORTHEAST LATE TONIGHT...BUT WILL REMAIN LIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JAS
NEAR TERM...PUMA
SHORT TERM...JAS
LONG TERM...MK
AVIATION...TDUD
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
332 PM CST THU DEC 18 2014
.SHORT TERM /TONIGHT/...
ISSUED AT 324 PM CST THU DEC 18 2014
SNOW HAS ENDED OVER THE SOUTHEASTERN CWA AS THE CULPRIT UPPER LEVEL
WAVE HAS RAPIDLY WEAKENED AND DGZ FORCING HAS WANED. BASED ON WEBCAM
IMAGES AND A FEW SPOTTER/COOP REPORTS...MOST AREAS IN THE SOUTHERN
THREE TIERS OF COUNTIES SAW LESS THAN AN INCH OF SNOW. ATTENTION NOW
TURNS UPSTREAM TO A LARGE STRATUS PLUME STRETCHING FROM NORTHWEST
MONTANA TO THE TEXAS PANHANDLE...WITH THE EASTERN FRONT NOW JUST
ABOUT TO ENTER THE WESTERN CWA. LIGHT WEST TO SOUTHWEST FLOW IN THE
LOWEST 1 KM OF THE ATMOSPHERE BEHIND A DEPARTING SURFACE RIDGE
SHOULD ADVECT THIS CLOUD MASS OVER CENTRAL IOWA TONIGHT AND KEEP
SKIES OVERCAST ALL NIGHT AND INTO TOMORROW MORNING. THE CLOUDS
SHOULD ALSO BOLSTER LOW TEMPS TONIGHT COMPARED TO PREVIOUS NIGHTS
AND DIDN`T DEVIATE MUCH FROM GUIDANCE IN THIS RESPECT.
THE BIGGEST UNCERTAINTY FOR TONIGHT IS THE POSSIBILITY OF FLURRIES
OR FREEZING DRIZZLE WEST OF I-35. SHORT-RANGE MODEL SOUNDINGS (RUC
AND HRRR IN PARTICULAR) SATURATE THE LOWEST 5 KFT OF THE ATMOSPHERE
IN THIS REGION TONIGHT WITH NEARLY ISOTHERMAL PROFILES IN THIS LAYER
HOVERING BETWEEN -4 AND -7C. WITH THIS CONDITIONAL ICE PROBABILITY
...WENT WITH A MIX OF OCCASIONAL FLURRIES AND PATCHY FZDZ. FORCING
SHOULD BE MARGINAL AT BEST AND NO ACCUMULATION OF SNOW OR ICE IS
ANTICIPATED. ANY LIFT WITH AN UPPER LEVEL TROUGH ON WATER VAPOR
IMAGERY NW OF THE CWA SHOULD STAY NORTH AND EAST OF THE AREA.
ISENTROPIC UPGLIDE IN THE LOWEST 100MB OF THE ATMOSPHERE IS
PRESENT...BUT AGAIN VERY WEAK.
.LONG TERM /FRIDAY THROUGH THURSDAY/...
ISSUED AT 324 PM CST THU DEC 18 2014
THE WEATHER IN THE LONG TERM WILL IN GENERAL BE MORE ACTIVE THEN
WHAT WE HAVE SEEN IN A WHILE. FRIDAY THROUGH SUNDAY THERE WILL BE
NUMEROUS RELATIVELY WEAK SHORT WAVES MOVE ACROSS IOWA IN A GENERALLY
ZONAL FLOW. THROUGH SATURDAY MOISTURE WILL EITHER BE SPARSE OR
SHALLOW SO I AM NOT EXPECTING MUCH WITH THESE SHORTWAVES IN TERMS OF
SENSIBLE WEATHER EXCEPT FOR CLOUD COVER. TEMPS SHOULD BE RATHER
MILD FOR MID TO LATE DECEMBER.
SATURDAY NIGHT THROUGH SUNDAY A LITTLE STRONGER SHORT WAVE MOVES IN
AND MOISTURE DEPTH INCREASES SLIGHTLY ALTHOUGH IT IS STILL VERY
SHALLOW. SOUNDINGS DO NOT INDICATE ICE INTRODUCTION AND WHILE THERE
ARE MODEL DIFFERENCES AS TO WHERE ANY WEAK FORCING MIGHT OCCUR...IT
DOES APPEAR THAT THE NORTHERN HALF OF IOWA IS MORE LIKELY TO SEE
THIS THAN SOUTHERN IOWA. AS A RESULT I KEPT THE MENTION OF FREEZING
DRIZZLE CONFINED TO THE NORTH. THE SOUNDING DOES SATURATE
OR BEGIN TO SATURATE SUFFICIENTLY LATE SATURDAY NIGHT THROUGH
SUNDAY MORNING THROUGH THE DENDRITIC ZONE THAT WE COULD TRANSITION
TO SOME LIGHT SNOW UP NORTH...ESPECIALLY SUNDAY MORNING. THAT
SHORTWAVE EXITS DURING THE EARLY AFTERNOON AND TEMPS WARM
SUFFICIENTLY FOR A WINTERY MIX CHANGING TO RAIN ACROSS AT LEAST
SOME OF THE AREA.
SUNDAY NIGHT THROUGH MONDAY A MORE POTENT SHORTWAVE MOVES INTO
IOWA...AFFECTING THE WEST SUNDAY NIGHT AND THE REST OF THE AREA
THROUGH TUESDAY. HERE MODELS DIVERGE ON HOW TO HANDLE THIS SYSTEM.
THE GFS KEEP THE UPPER LEVEL WAVE OPEN AND DEVELOPS A CLOSED SURFACE
LOW OVER CENTRAL TO NORTHEAST IOWA. THE EURO DRASTICALLY DEPEND
THE UPPER WAVE TO OUR WEST THEN CONTINUES TO DEVELOP IT INTO A
CLOSED LOW MONDAY NIGHT AND TUESDAY ACROSS EASTERN IOWA. THE
RESULTANT CLOSED SURFACE LOW IS OVER EASTERN IOWA AS WELL AND
FURTHER SOUTHWEST THAN THE GFS HAS. THE GFS REALLY DEVELOPS THE QG
FORCING ACROSS CENTRAL IOWA SUNDAY NIGHT THEN IS SIGNIFICANTLY
WEAKER THROUGH TUESDAY. SOUNDINGS SHOW A PROFILE THAT IS PRETTY
WARM THROUGH MONDAY AFTERNOON WHEN THE PROFILE COOLS TO BELOW
FREEZING. PRECIP THROUGH EARLY MONDAY AFTERNOON SHOULD BE RAIN WITH
AN OCCASIONAL WINTERY MIX ESPECIALLY UP NORTH. DURING THE AFTERNOON
WE WILL BE TRANSITIONING TO A RAIN/SNOW MIX BEFORE GOING TO ALL SNOW
MONDAY NIGHT. IT IS TOO FAR OUT TO CONSIDER SNOWFALL AMOUNTS YET
AND GIVEN THE MODEL DISCREPANCIES IT WOULD BE HARD TO DO AT THIS
POINT.
THAT SYSTEM PULLS OUT BY CHRISTMAS EVE LEAVING US WITH SEASONAL
TEMPS AND MAINLY DRY. ANOTHER SYSTEM PUSHES IN FOR THURSDAY NIGHT
AND FRIDAY AND GIVEN THE STRENGTH OF THE TROUGH OVER US THAT FAR OUT
WE WILL GET SOME PRECIP OUT OF THE SYSTEM BUT MODEL DISCREPANCIES
ARE TOO BIG TO GIVE MUCH IN THE WAY OF TIMING AND AMOUNT DETAILS.
&&
.AVIATION...18/18Z
ISSUED AT 1141 AM CST THU DEC 18 2014
SNOW IS WINDING DOWN ACROSS SOUTHERN IOWA THIS AFTERNOON WITH IFR
TO LOW MVFR CEILINGS LINGERING OVER THE AREA. IFR/LOW MVFR STRATUS
IS ALSO HANGING ON ACROSS PORTIONS OF NE IOWA. EXPECT LITTLE
IMPROVEMENT THROUGHOUT THE DAY WITH A LARGE SHIELD OF MVFR TO IFR
STRATUS OVER NEBRASKA AND WESTERN IOWA ADVECTING OVER CENTRAL IOWA
TONIGHT AND LINGERING THROUGH THE END OF THE TAF PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SKOW
LONG TERM...FAB
AVIATION...SKOW
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1045 AM MST THU DEC 18 2014
.UPDATE...
ISSUED AT 902 AM MST THU DEC 18 2014
UPDATE WAS JUST COMPLETED FOR THE RECENT EXPIRATION OF THE DENSE
FOG ADVISORY. SOME FOG WILL CONTINUE FOR THE NEXT HOUR OR SO.
UPDATE ISSUED AT 554 AM MST THU DEC 18 2014
EARLIER UPDATE WAS TO ISSUE DENSE FOG ADVISORY FOR OUR CWA. DENSE
FOG DEVELOPED FROM OAKLEY TO TRIBUNE TO BURLINGTON...BUT HAS BEEN
A BIT MORE VARIABLE ALONG THE KS/CO BORDER. SHORT RANGE GUIDANCE
GENERALLY FAVORS THE WESTERN PART OF THE CWA...THOUGH RAP DOES
SHOW THE PATCH OF FOG NEAR OAKLEY SPREADING A LITTLE BIT MORE TO
THE NORTH AND EAST TOWARD GRAHAM COUNTY. I AM NOT AS SURE ABOUT
HRRR WHICH ACTUALLY SHOWED FOG EXPANDING FROM THE COLORADO BORDER
TO THE EAST AND LINGERING THROUGH THE AFTERNOON. HIGHER SURFACE TD
VALUES ARE IN OUR EAST AND LIGHT FOG IS IN PLACE. I WOULD NOT BE
SURPRISED IF DENSE FOG COVERAGE INCREASED AND SPREAD EAST AROUND
OR AFTER SUNRISE...SO I DECIDED TO COVER THE ENTIRE AREA FOR THE
ADVISORY.
WHILE CURRENT DENSE FOG COVERAGE IS SOMEWHAT PATCHY...ROAD
CONDITIONS AFTER YESTERDAYS FREEZING DRIZZLE AND LAST NIGHTS LIGHT
SNOW ARE IN POOR CONDITION ACROSS MANY LOCATIONS. EVEN PATCHY
DENSE FOG WITH THESE ROAD CONDITIONS WOULD MAKE TRAVEL DANGEROUS.
I FELT MORE COMFORTABLE WITH A DENSE FOG ADVISORY THAN SPS DESPITE
THE VARIABLE NATURE OF THE CONDITIONS SO FAR THIS MORNING.
UPDATE ISSUED AT 412 AM MST THU DEC 18 2014
UPDATE TO CANCEL WINTER WEATHER ADVISORY. SNOW BAND HAS FALLEN
APART AND FREEZING DRIZZLE HAS COME TO AN END. UPPER LOW IS NOW
OVER NORTHEAST KS/SOUTHEAST NE. WHILE GOOD LOW LEVEL MOISTURE IS
SUPPORTING DENSE FOG REDEVELOPMENT...BETTER MOISTURE ADVECTION
WILL REMAIN EAST OF THE CWA THROUGH THE REST OF THE MORNING...SO
FREEZING DRIZZLE THREAT IS MINIMAL. I CANT JUSTIFY A WINTER
WEATHER ADVISORY JUST FOR FREEZING FOG...BUT FELT THE NEED TO KEEP
A SPS OUT TO COVER FREEZING FOG POTENTIAL. WILL MONITOR OVER THE
NEXT HOUR AND IF FOG CONTINUES TO INCREASE IN COVERAGE I MAY NEED
TO ISSUE DENSE FOG ADVISORY FOR THE MORNING HOURS.
&&
.SHORT TERM...(THIS MORNING THROUGH SATURDAY NIGHT)
ISSUED AT 244 AM MST THU DEC 18 2014
EARLY MORNING WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW SHORTWAVE
TROUGH OVER NORTHCENTRAL KANSAS WITH AREA OF SUBSIDENCE ALONG
SHORTWAVE RIDGE AXIS BUILDING INTO THE NEBRASKA PANHANDLE. AT THE
SURFACE A STATIONARY FRONT REMAINS IN PLACE OVER EASTERN COLORADO
WITH SOUTH TO SOUTHEAST FLOW IN PLACE ACROSS OUR CWA.
REGARDING WINTER WEATHER ADVISORY EARLY THIS MORNING....
RADAR AND SURROUNDING OBS SHOW A BAND OF LIGHT SNOW THAT FORMED ON
BACK SIDE OF H7 LOW MOVING EAST OVER OUR EASTERN CWA. THIS SNOW HAS
HELPED MIX OUT THE LOW LEVELS OF THE ATMOSPHERE WITH SHIFT IN LOW
LEVEL FLOW TO THE NORTHWEST AIDING IMPROVEMENT IN CONDITIONS
ACROSS THE WESTERN FORECAST AREA. BASED ON SHORT RANGE MODELS...I
AM STILL CONCERNED THAT LIGHT WINDS AND SHALLOW LOW LEVEL MOISTURE
COULD LEAD TO FREEZING FOG REDEVELOPMENT BEHIND THIS SNOW BAND.
FREEZING FOG/DRIZZLE WILL REMAIN POSSIBLE AHEAD OF IT WITH BETTER
MOISTURE ADVECTION/POOLING. OVERALL TREND THROUGH THE MORNING
SHOULD BE IMPROVEMENT IN CONDITIONS AROUND 12-15Z...WITH ANY FOG
CLEARING BY MIDDAY. AFTER 12Z I AM SKEPTICAL THAT FLOW WOULD ALLOW
FOR ENOUGH ADDITIONAL MOISTURE ADVECTION TO SUPPORT CONTINUED
FREEZING DRIZZLE...THOUGH FOG COULD BE POSSIBLE THROUGH MOST OF
THE MORNING ESPECIALLY IN THE EAST WHERE SOUTHERLY FLOW MAY LINGER
A LITTLE LONGER. WITH THIS IN MIND I PLAN ON HOLDING ONTO CURRENT
WINTER WEATHER ADVISORY THROUGH EXPIRATION IN CASE I NEED TO
EXTEND IT IN TIME FOR EASTERN LOCATIONS THROUGH 15Z.
REST OF TODAY...SHORTWAVE RIDGING WILL CONTINUE TO BUILD EAST
TODAY AND AIR MASS WILL BEING MODERATING AND DRYING AS SURFACE
TROUGH SHIFTS EAST. THERE MAYBE DECENT CLEARING WHICH COULD
SUPPORT TEMPS IN THE LOWER 40S (FOR LOCATIONS WITHOUT SNOW PACK).
IT IS TOUGH TO SAY HOW MUCH CLEARING AS MODELS HOLD ONTO STRATUS
OVER PARTS OF THE AREA INTO THE AFTERNOON. NOT A LOT OF
CONFIDENCE IN TEMPS...SO MADE MINOR ADJUSTMENT TO TODAYS HIGHS.
TONIGHT-SATURDAY NIGHT...A SHORTWAVE TROUGH WILL PASS THROUGH THE
SOUTHERN PLAINS THROUGH FRIDAY MORNING...WITH MINIMAL IMPACT ON
SENSIBLE WEATHER OVER OUR CWA. NAM AND SREF BL RH CONTINUE TO RUN
HIGH...LIKELY AS A RESULT OF SNOW PACK...AND SUPPORT FOG/STRATUS
DURING THE OVERNIGHT PERIODS. I ADDED PATCHY FOG TO TONIGHT AS
WINDS WILL BE LIGHT AND THERE COULD BE SOME LINGERING BL MOISTURE
POOLING ALONG AND EAST OF SURFACE TROUGH...THOUGH CONFIDENCE IS
PRETTY LOW AS TROUGH MAY BE EAST OF OUR CWA. THOUGH TEMPS WILL BE
SUBFREEZING...CONFIDENCE IS TOO LOW THAT ANY FOG WOULD BE DENSE
ENOUGH TO WORRY ABOUT ICE ACCUMULATION (FREEZING FOG). I AM
LEAVING FOG OUT OF FRIDAY NIGHT AND SATURDAY NIGHT TO SEE HOW
THINGS EVOLVE TONIGHT FIRST. SHORTWAVE RIDGE SHOULD BUILD BACK
OVER THE PLAINS FRIDAY THROUGH SATURDAY...WITH CONTINUED
MODERATION OF THE AIR MASS ALOFT. COMPLICATION TO TEMP FORECAST
WILL CONTINUE TO BE IMPACT OF DEEPER SNOW PACK IN OUR NORTHWEST
CWA.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 244 AM MST THU DEC 18 2014
THE LONG TERM PERIOD WILL START OUT WITH SLIGHTLY ABOVE AVERAGE
TEMPERATURES ON SUNDAY WITH WARM SOUTHERLY WINDS KEEPING
TEMPERATURES IN THE MID TO UPPER 40S. THE NEXT WEATHER MAKING
SYSTEM WILL APPROACH THE HIGH PLAINS REGION AS AN UPPER LEVEL TROUGH
AND SURFACE LOW PRESSURE SYSTEM MOVE ACROSS THE NORTHERN PLAINS.
THIS SYSTEM WILL BRING IN COLDER AIR TO THE PLAINS WITH CHANCES FOR
PRECIPITATION STARTING EARLY MONDAY MORNING...MOSTLY FOR EASTERN
COLORADO LOCATIONS.
PRECIPITATION MONDAY WILL BEGIN AS SNOW IN THE MORNING WITH COOLER
TEMPERATURES AT THE LOWER LEVELS...BUT WILL BECOME RAIN IN THE
AFTERNOON WITH HIGH TEMPERATURES REACHING THE MID 40S TO LOWER 50S.
AFTER SUNSET...PRECIPITATION WILL TRANSITION BACK TO SNOW THROUGH
THE OVERNIGHT HOURS. UNDER AN INCH OF SNOW IS POSSIBLE WITH THIS
SYSTEM.
THE UPPER LEVEL LOW IS DEPICTED IN GUIDANCE AS STALLING OVER THE
UPPER MIDWEST STATES...BUT THE TRI STATE AREA WILL BE UNDER THE
INFLUENCE OF STRONG NORTHWEST FLOW TUESDAY AS AN UPPER LEVEL RIDGE
BUILDS IN THE WEST. THE HIGHER AMPLITUDE RIDGE WILL BREAK DOWN AND
MOVE WESTWARD TO BRING A SHORTWAVE RIDGE OF HIGH PRESSURE OVER THE
CENTRAL PLAINS TO BRING DRY CONDITIONS AND NEAR AVERAGE TEMPERATURES
FOR TUESDAY AND WEDNESDAY. HIGH TEMPERATURES WILL RANGE FROM THE
UPPER 30S TO MID 40S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1041 AM MST THU DEC 18 2014
FOR KGLD...IFR NEAR LIFR CONDITIONS WILL END WITHIN THE NEXT HOUR.
AFTER THAT VFR CONDITIONS ARE EXPECTED THROUGH THE REST OF THE
PERIOD. SOME FOG COULD BE NEAR KGLD DURING THE NIGHT/EARLY MORNING
HOURS. HOWEVER...AM THINKING BECAUSE OF INCREASED MID/UPPER LEVEL
SKY COVER AND DOWNSLOPE WINDS...FOG WILL NOT AFFECT THE SITE.
FOR KMCK...IFR CEILINGS ARE EXPECTED FOR THE NEXT TWO TO THREE
HOURS BEFORE CLEARING. FROM 06Z TO 15Z...MVFR VISIBILITIES WILL
OCCUR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...DR
LONG TERM...MK
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
907 AM MST THU DEC 18 2014
.UPDATE...
ISSUED AT 902 AM MST THU DEC 18 2014
UPDATE WAS JUST COMPLETED FOR THE RECENT EXPIRATION OF THE DENSE
FOG ADVISORY. SOME FOG WILL CONTINUE FOR THE NEXT HOUR OR SO.
UPDATE ISSUED AT 554 AM MST THU DEC 18 2014
EARLIER UPDATE WAS TO ISSUE DENSE FOG ADVISORY FOR OUR CWA. DENSE
FOG DEVELOPED FROM OAKLEY TO TRIBUNE TO BURLINGTON...BUT HAS BEEN
A BIT MORE VARIABLE ALONG THE KS/CO BORDER. SHORT RANGE GUIDANCE
GENERALLY FAVORS THE WESTERN PART OF THE CWA...THOUGH RAP DOES
SHOW THE PATCH OF FOG NEAR OAKLEY SPREADING A LITTLE BIT MORE TO
THE NORTH AND EAST TOWARD GRAHAM COUNTY. I AM NOT AS SURE ABOUT
HRRR WHICH ACTUALLY SHOWED FOG EXPANDING FROM THE COLORADO BORDER
TO THE EAST AND LINGERING THROUGH THE AFTERNOON. HIGHER SURFACE TD
VALUES ARE IN OUR EAST AND LIGHT FOG IS IN PLACE. I WOULD NOT BE
SURPRISED IF DENSE FOG COVERAGE INCREASED AND SPREAD EAST AROUND
OR AFTER SUNRISE...SO I DECIDED TO COVER THE ENTIRE AREA FOR THE
ADVISORY.
WHILE CURRENT DENSE FOG COVERAGE IS SOMEWHAT PATCHY...ROAD
CONDITIONS AFTER YESTERDAYS FREEZING DRIZZLE AND LAST NIGHTS LIGHT
SNOW ARE IN POOR CONDITION ACROSS MANY LOCATIONS. EVEN PATCHY
DENSE FOG WITH THESE ROAD CONDITIONS WOULD MAKE TRAVEL DANGEROUS.
I FELT MORE COMFORTABLE WITH A DENSE FOG ADVISORY THAN SPS DESPITE
THE VARIABLE NATURE OF THE CONDITIONS SO FAR THIS MORNING.
UPDATE ISSUED AT 412 AM MST THU DEC 18 2014
UPDATE TO CANCEL WINTER WEATHER ADVISORY. SNOW BAND HAS FALLEN
APART AND FREEZING DRIZZLE HAS COME TO AN END. UPPER LOW IS NOW
OVER NORTHEAST KS/SOUTHEAST NE. WHILE GOOD LOW LEVEL MOISTURE IS
SUPPORTING DENSE FOG REDEVELOPMENT...BETTER MOISTURE ADVECTION
WILL REMAIN EAST OF THE CWA THROUGH THE REST OF THE MORNING...SO
FREEZING DRIZZLE THREAT IS MINIMAL. I CANT JUSTIFY A WINTER
WEATHER ADVISORY JUST FOR FREEZING FOG...BUT FELT THE NEED TO KEEP
A SPS OUT TO COVER FREEZING FOG POTENTIAL. WILL MONITOR OVER THE
NEXT HOUR AND IF FOG CONTINUES TO INCREASE IN COVERAGE I MAY NEED
TO ISSUE DENSE FOG ADVISORY FOR THE MORNING HOURS.
&&
.SHORT TERM...(THIS MORNING THROUGH SATURDAY NIGHT)
ISSUED AT 244 AM MST THU DEC 18 2014
EARLY MORNING WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW SHORTWAVE
TROUGH OVER NORTHCENTRAL KANSAS WITH AREA OF SUBSIDENCE ALONG
SHORTWAVE RIDGE AXIS BUILDING INTO THE NEBRASKA PANHANDLE. AT THE
SURFACE A STATIONARY FRONT REMAINS IN PLACE OVER EASTERN COLORADO
WITH SOUTH TO SOUTHEAST FLOW IN PLACE ACROSS OUR CWA.
REGARDING WINTER WEATHER ADVISORY EARLY THIS MORNING....
RADAR AND SURROUNDING OBS SHOW A BAND OF LIGHT SNOW THAT FORMED ON
BACK SIDE OF H7 LOW MOVING EAST OVER OUR EASTERN CWA. THIS SNOW HAS
HELPED MIX OUT THE LOW LEVELS OF THE ATMOSPHERE WITH SHIFT IN LOW
LEVEL FLOW TO THE NORTHWEST AIDING IMPROVEMENT IN CONDITIONS
ACROSS THE WESTERN FORECAST AREA. BASED ON SHORT RANGE MODELS...I
AM STILL CONCERNED THAT LIGHT WINDS AND SHALLOW LOW LEVEL MOISTURE
COULD LEAD TO FREEZING FOG REDEVELOPMENT BEHIND THIS SNOW BAND.
FREEZING FOG/DRIZZLE WILL REMAIN POSSIBLE AHEAD OF IT WITH BETTER
MOISTURE ADVECTION/POOLING. OVERALL TREND THROUGH THE MORNING
SHOULD BE IMPROVEMENT IN CONDITIONS AROUND 12-15Z...WITH ANY FOG
CLEARING BY MIDDAY. AFTER 12Z I AM SKEPTICAL THAT FLOW WOULD ALLOW
FOR ENOUGH ADDITIONAL MOISTURE ADVECTION TO SUPPORT CONTINUED
FREEZING DRIZZLE...THOUGH FOG COULD BE POSSIBLE THROUGH MOST OF
THE MORNING ESPECIALLY IN THE EAST WHERE SOUTHERLY FLOW MAY LINGER
A LITTLE LONGER. WITH THIS IN MIND I PLAN ON HOLDING ONTO CURRENT
WINTER WEATHER ADVISORY THROUGH EXPIRATION IN CASE I NEED TO
EXTEND IT IN TIME FOR EASTERN LOCATIONS THROUGH 15Z.
REST OF TODAY...SHORTWAVE RIDGING WILL CONTINUE TO BUILD EAST
TODAY AND AIR MASS WILL BEING MODERATING AND DRYING AS SURFACE
TROUGH SHIFTS EAST. THERE MAYBE DECENT CLEARING WHICH COULD
SUPPORT TEMPS IN THE LOWER 40S (FOR LOCATIONS WITHOUT SNOW PACK).
IT IS TOUGH TO SAY HOW MUCH CLEARING AS MODELS HOLD ONTO STRATUS
OVER PARTS OF THE AREA INTO THE AFTERNOON. NOT A LOT OF
CONFIDENCE IN TEMPS...SO MADE MINOR ADJUSTMENT TO TODAYS HIGHS.
TONIGHT-SATURDAY NIGHT...A SHORTWAVE TROUGH WILL PASS THROUGH THE
SOUTHERN PLAINS THROUGH FRIDAY MORNING...WITH MINIMAL IMPACT ON
SENSIBLE WEATHER OVER OUR CWA. NAM AND SREF BL RH CONTINUE TO RUN
HIGH...LIKELY AS A RESULT OF SNOW PACK...AND SUPPORT FOG/STRATUS
DURING THE OVERNIGHT PERIODS. I ADDED PATCHY FOG TO TONIGHT AS
WINDS WILL BE LIGHT AND THERE COULD BE SOME LINGERING BL MOISTURE
POOLING ALONG AND EAST OF SURFACE TROUGH...THOUGH CONFIDENCE IS
PRETTY LOW AS TROUGH MAY BE EAST OF OUR CWA. THOUGH TEMPS WILL BE
SUBFREEZING...CONFIDENCE IS TOO LOW THAT ANY FOG WOULD BE DENSE
ENOUGH TO WORRY ABOUT ICE ACCUMULATION (FREEZING FOG). I AM
LEAVING FOG OUT OF FRIDAY NIGHT AND SATURDAY NIGHT TO SEE HOW
THINGS EVOLVE TONIGHT FIRST. SHORTWAVE RIDGE SHOULD BUILD BACK
OVER THE PLAINS FRIDAY THROUGH SATURDAY...WITH CONTINUED
MODERATION OF THE AIR MASS ALOFT. COMPLICATION TO TEMP FORECAST
WILL CONTINUE TO BE IMPACT OF DEEPER SNOW PACK IN OUR NORTHWEST
CWA.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 244 AM MST THU DEC 18 2014
THE LONG TERM PERIOD WILL START OUT WITH SLIGHTLY ABOVE AVERAGE
TEMPERATURES ON SUNDAY WITH WARM SOUTHERLY WINDS KEEPING
TEMPERATURES IN THE MID TO UPPER 40S. THE NEXT WEATHER MAKING
SYSTEM WILL APPROACH THE HIGH PLAINS REGION AS AN UPPER LEVEL TROUGH
AND SURFACE LOW PRESSURE SYSTEM MOVE ACROSS THE NORTHERN PLAINS.
THIS SYSTEM WILL BRING IN COLDER AIR TO THE PLAINS WITH CHANCES FOR
PRECIPITATION STARTING EARLY MONDAY MORNING...MOSTLY FOR EASTERN
COLORADO LOCATIONS.
PRECIPITATION MONDAY WILL BEGIN AS SNOW IN THE MORNING WITH COOLER
TEMPERATURES AT THE LOWER LEVELS...BUT WILL BECOME RAIN IN THE
AFTERNOON WITH HIGH TEMPERATURES REACHING THE MID 40S TO LOWER 50S.
AFTER SUNSET...PRECIPITATION WILL TRANSITION BACK TO SNOW THROUGH
THE OVERNIGHT HOURS. UNDER AN INCH OF SNOW IS POSSIBLE WITH THIS
SYSTEM.
THE UPPER LEVEL LOW IS DEPICTED IN GUIDANCE AS STALLING OVER THE
UPPER MIDWEST STATES...BUT THE TRI STATE AREA WILL BE UNDER THE
INFLUENCE OF STRONG NORTHWEST FLOW TUESDAY AS AN UPPER LEVEL RIDGE
BUILDS IN THE WEST. THE HIGHER AMPLITUDE RIDGE WILL BREAK DOWN AND
MOVE WESTWARD TO BRING A SHORTWAVE RIDGE OF HIGH PRESSURE OVER THE
CENTRAL PLAINS TO BRING DRY CONDITIONS AND NEAR AVERAGE TEMPERATURES
FOR TUESDAY AND WEDNESDAY. HIGH TEMPERATURES WILL RANGE FROM THE
UPPER 30S TO MID 40S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 439 AM MST THU DEC 18 2014
LINGER LOW LEVEL MOISTURE HAS SUPPORTED FREEZING FOG REDEVELOPMENT
ACROSS NW KANSAS WHICH IS SPREADING INTO EASTERN COLORADO AND
SOUTHWEST NEBRASKA. VLIFR CONDITIONS ARE ALREADY IN PLACE AT
KGLD...AND CONDITIONS SHOULD DETERIORATE AT KMCK OVER THE NEXT
HOUR. VLIFR CONDITIONS SHOULD EVENTUALLY TRANSITION TO MVFR AND
THEN VFR BY LATE MORNING AS MAIN MOISTURE AXIS SHIFTS EAST. THERE
IS A POSSIBILITY THAT LOW STRATUS MAY LINGER THROUGH THE AFTERNOON
AND FOG/STRATUS POSSIBLY REDEVELOP LATER TONIGHT. HOWEVER...MODEL
DATA MAY BE OVERLY INFLUENCED BY LINGERING SNOW PACK...SO I KEPT
CONDITIONS VFR AFTER MIDDAY FOR BOTH TAFS. WINDS SHOULD REMAIN
LIGHT AROUND 5KT OR LESS THROUGH THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...DR
LONG TERM...MK
AVIATION...DR
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
145 PM EST THU DEC 18 2014
.UPDATE...
ISSUED AT 145 PM EST THU DEC 18 2014
DID A QUICK UPDATE TO THE GRIDS TO REMOVE ALL BUT THE SPRINKLE AND
FLURRY CHANCES INTO THE EVENING. ALSO FINE TUNED THE HOURLY T AND TD
GRIDS PER THE LATEST OBS AND TRENDS...ALONG WITH THE MAXT GRID. THESE
HAVE BEEN SENT TO THE NDFD AND WEB SERVERS ALONG WITH FRESH ISSUANCES
OF THE HWO AND ZFP.
UPDATE ISSUED AT 1025 AM EST THU DEC 18 2014
14Z SFC ANALYSIS SHOWS A VERY WEAK AREA OF LOW PRESSURE SLIDING BY TO
THE SOUTH OF EASTERN KENTUCKY. THE PRECIPITATION WITH THIS...MAINLY
FLURRIES...IS FADING FAST WITH MOSTLY VIRGA LEFT. TEMPERATURES ARE
GENERALLY IN IN THE UPPER 20S AND LOWER 30S THROUGH THE AREA WITH
DEWPOINTS IN THE MID AND UPPER 20S...WHILE WINDS ARE LIGHT. SATELLITE
SHOWS A FEW BREAKS OUT THERE BUT CIGS ARE MAINLY IN THE LOW MVFR
RANGE NORTH AND VFR SOUTH. HAVE UPDATED THE FORECAST TO DIMINISH THE
POPS QUICKLY THROUGH MIDDAY IN CONJUNCTION WITH THE 12Z NAM12 AND
LATEST HRRR. ALSO FINE TUNED HIGH TEMPERATURES AND THE HOURLY T/TD
GRIDS PER THE LATEST OBS...TRENDS...AND CONSSHORT GUIDANCE. THESE
HAVE BEEN SENT TO THE NDFD AND WEB SERVERS ALONG WITH AN UPDATE TO
THE HWO AND ZONES.
UPDATE ISSUED AT 552 AM EST THU DEC 18 2014
THERE IS A FAIR AMOUNT OF RADAR RETURNS MAKING IT INTO SOUTHEAST
KY...UNLIKE WHAT MANY OF THE HI RES MODELS WERE SHOWING EARLIER.
DESPITE THE DRY AIR IN PLACE AT THE SURFACE...DEW POINT DEPRESSIONS
HAVE LESSENED TO 0 IN SOME OF OUR SOUTHWESTERN COUNTIES. AND WITH
SNOW AND SLEET BEING REPORTED ONLY A FEW COUNTIES OVER...DECIDED IT
WAS TIME TO GO AHEAD AND EXPAND THE CHANCES FOR PRECIP THIS MORNING.
AS IT IS NOW...IT LOOKS LIKE ALL OF THE COUNTIES ALONG THE TENNESSEE
BORDER...AS WELL AS THE NEXT TIER OF COUNTIES NORTHWARD WILL LIKELY
BE AFFECTED BY LIGHT SNOW AND POTENTIAL SLEET THIS MORNING. LATEST HI
RES MODELS...INCLUDING THE HRRR AND NAM 12 ARE SHOWING THE SYSTEM
LOSING INTENSITY VERY QUICKLY THIS MORNING...AND CUTTING OFF PRECIP
CHANCES ACROSS OUR CWA WITHIN THE NEXT FEW HOURS. HOWEVER...GIVEN THE
LEVEL OF UNCERTAINTY...AND THE ONGOING STRONG REFLECTIVITIES...ERRED
ON THE PESSIMISTIC SIDE AND KEPT MENTION OF SNOW AND ICE IN UNTIL MID
MORNING. ALSO...WENT AHEAD AND ISSUED A SPECIAL WEATHER STATEMENT
THROUGH 15Z FOR THE AFFECTED COUNTIES SINCE ANY PRECIP WILL LIKELY
ACCUMULATE ON SURFACES DURING THE MORNING COMMUTE.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 358 AM EST THU DEC 18 2014
SURFACE HIGH PRESSURE CONTINUES TO BE IN CHARGE FOR THE OHIO RIVER
VALLEY AND MANY POINTS TO OUR NORTH AND SOUTH. STRONG SUBSIDENCE
TRAPPING LOW LEVEL MOISTURE ACROSS THE NE PORTION OF THE CWA HAS LED
TO CONTINUED MVFR CLOUDS...WHICH ACCORDING TO THE LATEST FORECAST
SOUNDINGS...SHOULDN/T BE BUDGING UNTIL SOMETIME EARLY THIS
AFTERNOON. MEANWHILE...ALOFT...A SHORTWAVE IS CONTINUING TO DAMPEN
AS IT TRACKS EASTWARD...AND SHOULD BE POISED TO REACH THE
MISSISSIPPI RIVER VALLEY BETWEEN 12 AND 18Z TODAY. SO FAR...THIS
SYSTEM HAS BROUGHT LIGHT PRECIP ACROSS FAR SW KY...AS IT CONTINUES
TO SHIFT EASTWARD TOWARDS OUR SW CWA DURING THE EARLY MORNING HOURS.
THE AMOUNT OF LOW LEVEL DRY AIR IS STILL A CONCERN IN THIS AREA OF
THE CWA...AND WHETHER OR NOT THE PRECIP CAN OVERCOME IT. EXPECTING
BEST CHANCES FOR WEATHER ACROSS WAYNE AND MCCREARY COUNTIES GIVEN
THE LATEST HI RES MODEL DATA...INCLUDING THE HRRR AND ECMWF.
FORECAST SOUNDINGS ARE SHOWING BELOW FREEZING SURFACE TEMPS AT THESE
LOCATIONS...BUT WITH THE POTENTIAL FOR A SLIGHT WARM NOSE TEETERING
ALONG THE FREEZING LINE SEVERAL THOUSAND FEET ABOVE GROUND THROUGH
18Z. AS SUCH...WENT AHEAD AND MENTIONED SOME ICE PELLETS ALONG WITH
A CHANCE OF SNOW IN THESE TWO COUNTIES...WITH A SLIGHT CHANCE OF
LIGHT SNOW EVENTUALLY MIXING WITH RAIN AFTERWARDS ELSEWHERE IN THE
SW CWA.
THE SHORTWAVE WILL EVENTUALLY FLATTEN AND SHIFT EAST OF KY BY 06Z
FRIDAY ELIMINATING ANY FURTHER PRECIP CONCERNS FOR THE SHORT TERM.
THE ONE CAVEAT WILL BE THE EXISTENCE OF THE MID LEVEL CLOUDS WITH
MUCH OF THE TEMPERATURE PROFILE /INCLUDING SURFACE TEMPS/ DROPPING
BELOW FREEZING BY THIS EVENING AND THROUGHOUT THE OVERNIGHT. A FEW
FLURRIES MAY GET SQUEEZED OUT ACROSS THE CWA DURING THE EVENING. IN
FACT...MAY NOT HAVE EXTENDED THE FLURRY POTENTIAL FAR ENOUGH ACROSS
THE CWA. BUT THE CONFIDENCE IS STILL QUITE LOW ON THIS SUBJECT.
CONTINUED TO GO ABOVE GUIDANCE FOR CLOUD COVER OVER THE NEXT 36
HOURS AS MID/LOW LEVEL CLOUDS LOOK TO STICK AROUND THROUGH
FRIDAY...BEFORE ANOTHER ROUND OF HIGH CLOUDS WORKS INTO THE CWA.
THIS MAY INHIBIT SOME OF THE BEST RIDGE VALLEY SPLIT POTENTIAL
TONIGHT. OVERALL...TEMPERATURES SHOULD/T DEVIATE MUCH FROM WHAT WAS
SEEN IN THE PREVIOUS 24 HOURS. HIGHS TODAY WILL GENERALLY BE IN THE
UPPER 30S AND LOW 40S...WITH OVERNIGHT LOWS TONIGHT DROPPING DOWN
INTO THE UPPER 20S. WINDS AT THE SURFACE WILL REMAIN QUITE LIGHT AND
VARIABLE THROUGH THE SHORT TERM...WHILE ABOVE THE CONTINUED MID
LEVEL SUBSIDENCE INVERSION...THEY WILL INCREASE RAPIDLY THANKS TO A
WEST TO EAST ORIENTED JET STREAK WHICH IS CURRENTLY PUSHING ALONG
AND SOUTH OF KY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014
A FAIRLY ACTIVE PATTERN IN STORE FOR THE EXTENDED PORTION OF THE
FORECAST. THE MODELS AREA IN PRETTY GOOD AGREEMENT WITH THE LARGE
SCALE UPPER LEVEL FLOW PATTERN THROUGH MID WEEK. THREE SYSTEMS ARE
FORECAST TO AFFECT EASTERN KENTUCKY...THE FIRST BEING A WEAK AREA OF
LOW PRESSURE THAT IS FORECAST TO FORM OVER THE SOUTHERN PLAINS AND
THEN PROGRESS EASTWARD ACROSS THE GULF COAST FRIDAY NIGHT THROUGH
SATURDAY NIGHT. THE SECOND AND THIRD WEATHER SYSTEMS TO AFFECT THE
REGION...SHOULD THE MODELS PAN OUT...WOULD COME MONDAY THROUGH
WEDNESDAY OF NEXT WEEK. THE FIRST OF THESE LATE PERIOD SYSTEMS IS
PROGGED TO ORIGINATE OVER THE GULF OF MEXICO AND MOVE UP THE EASTERN
SLOPES OF THE APPALACHIAN MOUNTAINS MONDAY AND MONDAY NIGHT. THE
SECOND WEATHER SYSTEM IN THIS SCENARIO IS FORECAST TO TAKE SHAPE
OVER THE NORTHERN PLAINS TO BEGIN THE NEW WORK WEEK. THIS SECOND
SYSTEM WOULD COME IN THE FORM OF A LARGE SCALE AND MUCH DEEPER
TROUGH THAN EITHER OF THE SOUTHERN STREAM SYSTEMS. THIS AREA OF LOW
PRESSURE WOULD PROVIDE THE SOURCE OF COLD AIR THAT COULD BRING SUB
FREEZING TEMPERATURES AND SNOW NEXT WEDNESDAY NIGHT.
THE UNCERTAINTY WITH THIS WEEKENDS WEATHER WILL REVOLVE AROUND HOW
MUCH COLD AIR WILL BE ABLE TO FILTER INTO THE AREA AS THE SOUTHERN
PLAINS LOW MAKES ITS NORTHEASTERN TURN FRIDAY NIGHT. BASED ON THE
LATEST MODEL SOUNDINGS AND TIME HEIGHTS...THERE IS SOME UNCERTAINTY
AS TO HOW FAR SOUTH THE COLD AIR WILL PENETRATE FRIDAY NIGHT INTO
SATURDAY MORNING. BASED ON THIS...DECIDED TO CONFINE ANY
ACCUMULATING SNOW TO THE AREA NORTH OF THE MOUNTAIN PARKWAY BETWEEN
6 AND 12Z FRIDAY NIGHT. THE SNOW SHOULD THEN TRANSITION TO A RAIN
SNOW MIX EARLY SATURDAY MORNING...AND THEN TO ALL RAIN BY EARLY
SATURDAY AFTERNOON. ANY SNOW ACCUMULATIONS THAT DO OCCUR WOULD
LIKELY BE CONFINED TO GRASSY AREAS AND ELEVATED SURFACES. OUR FAR
EASTERN COUNTIES COULD SEE ANOTHER SHOT OF RAIN SNOW MIX OR ALL SNOW
FOR A BRIEF PERIOD SATURDAY NIGHT AS THE LOW EXITS THE AREA AND
WINDS SHIFT TO THE NORTH NORTHEAST. A WEAK RIDGE OF HIGH PRESSURE
ALOFT SHOULD PROVIDE A BRIEF RESPITE FROM THE WINTRY WEATHER LATE
SATURDAY NIGHT THROUGH MID MORNING ON SUNDAY. THE MODELS ONCE AGAIN
OFFER UP SOME UNCERTAINTY AS TO EXACTLY WHEN PRECIPITATION ONSET
WILL BE ON SUNDAY...WITH THE GFS MODEL HOLDING OFF A LOT LONGER THAN
THE ECMWF. BASED ON THIS...WENT WITH A BLEND BETWEEN THE TWO MODELS
FOR PRECIP ONSET ON SUNDAY ACROSS OUR EASTERN COUNTIES...WITH LIGHT
RAIN AFFECTING THE SOUTHEASTERN TWO THIRDS OF THE AREA AS MOISTURE
FROM THE GULF LOW BEGINS TO MOVE NORTHWARD INTO THE AREA. THE BETTER
SHOT OF PRECIPITATION WILL COME FROM MONDAY NIGHT THROUGH WEDNESDAY
EVENING...AS A MUCH STRONGER AND WETTER WEATHER SYSTEM DIVES OUT OF
THE NORTHERN PLAINS AND PHASES WITH WHAT EVER ENERGY IS LEFT OVER
FROM THE GULF OF MEXICO WEATHER SYSTEM. MOST OF THE PRECIPITATION
WITH THIS THIRD WEATHER SYSTEM LOOKS TO BE IN THE FORM OF RAIN BASED
ON THE TEMPERATURE PROFILES SEEN IN THE LATEST MODEL DATA. COULD SEE
SOME MORE SNOW WITH THIS FINAL WEATHER SYSTEM AS WINDS SHIFT TO THE
WEST AND NORTHWEST BEHIND THE LOW AS IT MOVES INTO NEW ENGLAND AND
COLDER AIR SPILLS INTO THE REGION.
THE OTHER WEATHER CONCERN OF NOTE FOR THE END OF THE EXTENDED PERIOD
WILL BE WINDS...PARTICULARLY FROM WEDNESDAY ONWARD. THE MODELS ALL
AGREE THAT A WELL DEVELOPED PRESSURE GRADIENT WILL ACCOMPANY THE
GREAT PLAINS WEATHER SYSTEM AS IT MOVES EAST. SUSTAINED WEST TO
NORTHWEST WINDS OF 10 TO 15 MPH...WITH GUSTS OF 20 TO 25 MPH...WILL
NOT BE OUT OF THE QUESTION. TEMPERATURES THROUGHOUT THE EXTENDED
PERIOD LOOK TO BE AT OR SLIGHTLY ABOVE NORMAL FROM SUNDAY THROUGH
WEDNESDAY. THE WARMEST STRETCH DURING THAT TIME WOULD BE MONDAY AND
TUESDAY...AS WINDS SHIFT TO THE SOUTH AHEAD OF THE MID WEEK WEATHER
SYSTEM. HIGHS ON EACH OF THOSE DAYS ARE EXPECTED TO TOP OUT IN THE
UPPER 40S AND LOWER 50S RESPECTIVELY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 125 PM EST THU DEC 18 2014
SURFACE HIGH PRESSURE HAS BASICALLY WON OUT OVER THE AREA...
EVAPORATING ALL THE LIGHT RADAR RETURNS BEFORE THEY REACH THE GROUND.
THE LOWER CLOUDS ACROSS THE NORTH ARE EXPECTED TO BREAK UP DURING THE
AFTERNOON WHILE HIGH AND MID ONES REMAIN. CANNOT RULE OUT AN ODD
FLURRY OR SPRINKLE THROUGH THE EVENING...BUT MOST LOCATIONS WILL
REMAIN PCPN FREE. THE VFR CIGS WILL LOWER TONIGHT INTO FRIDAY MORNING
BUT THERE SHOULDN/T BE ANY RESTRICTIONS. EVEN THESE CLOUDS WILL
LIKELY BREAK UP DURING THE DAY FRIDAY KEEPING CONDITIONS VFR. WINDS
THROUGH THE PERIOD WILL BE LIGHT AND MAINLY FROM THE NORTHWEST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...JMW
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1201 PM CST THU DEC 18 2014
.DISCUSSION...
FOR 18Z TAF ISSUANCE.
&&
.AVIATION...
GENERALLY CARRIED THE PREVIOUS THINKING FOR THE DEVELOPMENT OF OUR
EXPECTED RAINFALL EVENT OVER THE NEXT 24 HOURS. MSAS SFC ANALYSIS
SHOWS A BIT OF A TROF EXTENDING SW-NE KINDA BISECTING THE FORECAST
AREA...AND THIS FEATURE APPEARS TO BE THE DEMARCATION LINE
BETWEEN LOW CEILINGS (<1K FEET) AND VFR CIGS. EXPECT ALL SITES TO
BE MVFR OR LOWER BY LATE AFTERNOON BEFORE GOING IFR OR WORSE FOR
THE REMAINDER OF THE PERIOD TONIGHT. LOCAL 88DS SHOW RAINS
LINGERING OVER MAINLY CNTL LA BUT THIS AREA OF PRECIP HAS ALREADY
PASSED KAEX. AS FAR AS THE SRN SITES...WILL CONTINUE TO HAVE TO
WATCH AN AREA OF RAIN OVER THE GULF WHICH COULD IMPACT THE SERN
SITES ALTHOUGH FOR NOW HAVE JUST RETAINED A VCSH MENTION THERE AS
TRAJECTORIES APPEAR TO CARRY THIS PRECIP S OF THE AREA. EXPECT
PREVAILING RAINS TO DEVELOP LATE TONIGHT AS THE WARM FRONT OVER
THE COASTAL WATERS BEGINS PUSHING NWD...AND ADDITIONAL ENERGY FROM
A SHORTWAVE ALOFT ALSO WORKS INTO THE MIX.
25
&&
.PREV DISCUSSION... /ISSUED 957 AM CST THU DEC 18 2014/
UPDATE...
WARM FRONTAL BOUNDARY SITTING OFF THE COAST MAKING FOR A MESSY
WEATHER PICTURE TODAY THROUGH FRIDAY. LOOKING AT THE CURRENT RADAR...
AN AREA OF RAIN AND SHOWERS ORIENTED SOUTHWEST TO NORTHEAST WILL
CONTINUE TO SLIDE EAST AND FILL IN SOUTHWARD CLOSE TO THE WARM FRONT.
UPDATED RAIN CHANCES REST OF THIS MORNING INTO THIS AFTERNOON TO COME
INTO AGREEMENT WITH THE LOCAL WRF MODEL AS WELL AS THE HIGH
RESOLUTION HRRR WHICH ARE BOTH SIGNALING RAIN COVERAGE INCREASING
THROUGHOUT THE DAY. TEMPERATURES LOOK REASONABLE...ONLY ADJUSTED DOWN
ONE TINY NOTCH. INCREASED CLOUD COVER TODAY AS WELL...IT IS GOING
TO BE MOSTLY CLOUDY FOR THE REMAINDER OF THE DAY.
PREV DISCUSSION... /ISSUED 545 AM CST THU DEC 18 2014/
AVIATION UPDATE...REGARDING 12Z TAF ISSUANCE. MVFR CEILINGS NOW
OVER OUR TERMINALS OF AEX AND BPT WILL OVERSPREAD THE REMAINDER OF
THE AREA AS THE MORNING PROGRESSES. THIS NORTH OF A WARM FRONT NOW
OVER THE NEAR COASTAL WATERS THAT IS EXPECTED TO RETREAT INTO THE
INLAND AREA THROUGH THE DAY. SCATTERED SHOWERS ARE ON TAP ALONG AND
AHEAD OF THE BOUNDARY. CARRYING VCSH AND TEMPO GROUPS AT VARIOUS
TIMES AT ALL TERMINALS. RAIN CHANCES THEN DIMINISH BY EARLY
EVENING...RAMPING UP AGAIN LATE TONIGHT WITH THE APPROACH OF A
SHORTWAVE TROF ADVANCING EAST ACROSS TEXAS.
MARCOTTE
PREV DISCUSSION... /ISSUED 501 AM CST THU DEC 18 2014/
DISCUSSION...
TEMPERATURES AROUND THE NATION RANGED FROM SINGLE DIGITS ACROSS
THE UPPER PLAINS STATES TO THE LOWER 70S AT BROWNSVILLE IN DEEP
SOUTH TEXAS.
THE WEATHER TODAY LOOKS TO BE A MESS AS WE BEGIN ANOTHER TRANSITION
TO A COLD FRONTAL PASSAGE LATE FRIDAY TIME FRAME. UNTIL THEN A
SURFACE LOW IS DEVELOPING OVER DEEP SOUTH TEXAS AND WILL LIFT
NORTHEAST TODAY DRAGGING WITH IT A WARM FRONT. RAINS TODAY ARE
GOING TO RIDE UP AND OVER THE WARM FRONT THAT IS LOCATED TO OUR
SOUTHWEST THIS MORNING. ISOLATED THUNDERSTORMS THIS AFTERNOON INTO
TONIGHT. TEMPS WILL RANGE FROM NEAR 70 BEHIND THE WARM FRONT IN
BEAUMONT TO 60 FOR THE LAKES REGION IN SOUTHEAST TEXAS AND CENTRAL
LOUISIANA UNDER CLOUDY SKIES. WINDS WILL REMAIN FROM THE NORTHEAST
INLAND TO EAST ALONG THE COAST TO SOUTHEAST IN THE COASTAL WATERS.
TONIGHT WILL SEE SHOWERS AND ISOLATED THUNDERSTORMS... TEMPERATURES
NOT AS COOL AS THIS MORNING AS THE WARM FRONT WILL LAY ALONG THE
I-10 CORRIDOR. THIS BOUNDARY WILL MORE OR LESS REMAIN STATIONARY
INTO FRIDAY MORNING TIME FRAME. SOUTH OF THE WARM FRONT THERE WILL
BE IS A CHANCE THAT SEVERAL STORMS MAY BECOME SEVERE WITH WINDS
THE MAIN THREAT. HEAVY RAINS ARE ALSO EXPECTED FOR THE LAKES
REGION IN SOUTHEAST TEXAS AND ACROSS CENTRAL LOUISIANA NORTH OF
THE WARM FRONT. AS THE LOW MOVES INTO SOUTHERN LOUISIANA ON FRIDAY
THIS WILL DRAG COOLER AND DRIER AIR DOWN INTO TEXAS WITH A COLD
FRONT PUSHING INTO SOUTHEAST TEXAS LATE IN THE DAY. THIS LATEST
FRONT IS EXPECTED TO EXIT SOUTH CENTRAL LOUISIANA FRIDAY EVENING
WITH RAINS ENDING EARLY SATURDAY MORNING. THE WEEKEND LOOKS TO BE
COOLER AND DRIER ALTHOUGH IT WILL TAKE AWHILE TO DRY OUT.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 65 55 64 46 57 / 60 60 90 30 10
KBPT 69 57 66 47 58 / 50 70 90 20 10
KAEX 56 50 53 42 54 / 50 70 90 50 10
KLFT 66 56 65 48 58 / 50 40 90 40 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&
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&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
332 PM EST THU DEC 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM EST THU DEC 18 2014
AN UPPER RIDGE STRETCHING FROM MINNESOTA THROUGH NORTHWEST ONTARIO
WILL BE THE MAIN FEATURE CONTROLLING THE WEATHER OVER THE UPPER
GREAT LAKES REGION OVER THE NEXT 24 HOURS. BENEATH THIS UPPER
RIDGE...A 1029MB SURFACE HIGH SITS JUST TO THE NORTH OF THE
MINNESOTA WHILE THE SURFACE TROUGH THAT LED TO THE SNOW YESTERDAY
IS OVER NORTHERN LAKE MICHIGAN AND NORTHERN LOWER MICHIGAN AND
WEAKENING. NORTH-NORTHEASTERLY FLOW AROUND THIS HIGH HAS PULLED
DRIER AIR INTO THE UPPER GREAT LAKES REGION...LEADING TO CLEARING
SKIES THIS PAST EVENING OVER MUCH OF LAKE SUPERIOR. BUT MOISTURE
TRAPPED BELOW THE SUBSIDENCE INVERSION...AND COMBINED WITH UPSLOPE
FLOW...HAS LED TO LOW CLOUDS PERSISTING OVER A GOOD PORTION OF
UPPER MICHIGAN EARLY THIS MORNING. THERE ARE A COUPLE SPOTS WHERE
THE CLOUDS DID CLEAR OUT...GENERALLY OVER THE KEWEENAW PENINSULA
AND ALSO IT/S STARTING TO OVER THE EAST. WHERE SKIES CLEARED
OUT...3AM TEMPERATURES ARE IN THE SINGLE DIGITS ABOVE ZERO (6
DEGREES AT KCMX)...WHILE THE CLOUDS HAVE KEPT THE TEMPERATURES IN
THE UPPER TEENS AND LOWER 20S ELSEWHERE. STILL SEEING LIGHT
FLURRIES HERE AT OUR OFFICE AT 330AM...SO WILL CONTINUE TO MENTION
ISOLATED FLURRIES IN THE FORECAST FOR THE UPSLOPE LOCATIONS THROUGH
DAYBREAK.
WITH THE UPPER RIDGE AND SURFACE HIGH MOVING OVER THE AREA
TODAY...EXPECT CONTINUED QUIET CONDITIONS FOR THE SHORT TERM
PERIOD. THERE ARE TWO AREAS OF FOCUS IN THE SHORT TERM
PERIOD...FIRST THE LOW CLOUDS AND THEIR DIMINISHMENT AND THEN THE
POTENTIAL FOR SOME FREEZING FOG OVERNIGHT TONIGHT. FOR THE LOW
CLOUDS...KMQT VWP INDICATES CLOUD TOPS AROUND 2.5KFT...WHICH
MATCHES UP WELL WITH THE INVERSION INDICATED ON THE MODELS AT
900MB. THE BIG QUESTION IS WHEN WILL THEY DISSIPATE TODAY. AT
THIS TIME OF THE YEAR WITH THE LOW SUN ANGLE AND LIMITED
MIXING...THERE IS LITTLE DAY TIME HELP AND WILL NEED TO RELY ON THE
ADVECTION OF DRIER AIR INTO THE AREA. UNFORTUNATELY...THIS IS WHERE
THE MODELS TEND TO DIFFER. THE 00Z NAM HOLDS ONTO THE CLOUDS FOR
MUCH OF THE DAY AND EVEN THROUGH THE NIGHT TONIGHT...BUT THINK THAT
IS LARGELY TIED TO IT TRADITIONALLY OVER DOING LOW LEVEL MOISTURE.
THAT APPEARS TO THE CASE EARLY THIS MORNING...WHERE IT HAS THE LOW
CLOUDS JUST TO THE WEST OF JAMES BAY BEING MUCH FARTHER TO THE
SOUTH AND SUPPOSEDLY ENTERING NORTHERN LAKE SUPERIOR AT THIS TIME.
THE RECENT RAP (ALONG WITH THE HRRR) RUNS ALSO HOLD ONTO THE CLOUDS
FOR MUCH OF THE DAY BEFORE CLEARING THEM OUT THIS AFTERNOON...BUT IT
APPEARS TO HAVE THE LOW LEVEL MOISTURE FARTHER NORTH OVER LAKE
SUPERIOR THAN WHAT IS ACTUALLY OCCURRING. THE MORE OPTIMISTIC
RUNS...WHICH SEEM TO HAVE A BETTER HANDLE ON THE LOCATION OF THE
LOW CLOUDS ARE THE 00Z GFS/ECMWF. THEY HOLD ONTO THE LOW CLOUDS
OVER THE NORTH CENTRAL AND WEST FOR THE FIRST PART OF THE MORNING
AND THEN SCATTER THEM OUT THROUGH THE LATER PART OF THE MORNING AND
EARLY AFTERNOON. WILL FOLLOW THAT IDEA AT THIS POINT FOR THE CLOUD
COVER FORECAST FOR TODAY. MEANWHILE OVER THE EAST...THE ADVECTION
OF THE DRIER AIR AND LITTLE UPSLOPE HELP SHOULD ALLOW THE LOW
CLOUDS TO DISSIPATE DURING THE FIRST PART OF THE MORNING. THAT DRY
AIR HAS ALREADY SCATTERED THE CLOUDS OUT OVER LUCE COUNTY AND
STARTING TO SEE IT WORK INTO ALGER/SCHOOLCRAFT COUNTIES. AS FOR
HIGHS TODAY...EXPECT THEM TO BE IN THE MID-UPPER 20S OVER MUCH OF
THE AREA.
FOLLOWING THE IDEA OF THE CLOUDS DIMINISHING TODAY...WOULD EXPECT A
VERY GOOD RADIATIONAL COOLING NIGHT TONIGHT UNDER THE CENTER OF THE
HIGH. THUS...WILL CONTINUE THE IDEA OF GOING AT OR BELOW THE
COLDEST GUIDANCE. THE GEM MODELS USUALLY PERFORM WELL IN
RADIATIONAL COOLING NIGHTS AND THEY HAVE LOWS IN THE LOWER SINGLE
DIGITS WHERE THEY ARE NOT INDICATING CLOUDS (ALTHOUGH THE REGIONAL
GEM REDEVELOPS LOW CLOUDS OVER THE HIGHER TERRAIN OF THE NORTH
CENTRAL TONIGHT). THUS...HAVE LOWS IN THE SINGLE DIGITS ABOVE ZERO
TO AROUND ZERO OVER THE INTERIOR LOCATIONS. WITH KCMX DROPPING TO 6
DEGREES AT 3AM THIS MORNING...THAT SUPPORTS TO EXPECTATIONS FOR
TONIGHT. THIS EXPECTED DROP IN TEMPS WILL LEAD TO THE POTENTIAL FOR
PATCHY FREEZING FOG OR AT LEAST SOME SOLID FROST. WITH DEWPOINTS IN
THE MID-UPPER TEENS TODAY...TEMPS SHOULD EASILY DROP THROUGH THOSE
VALUES THIS EVENING. DEWPOINTS THIS PAST EVENING AT KCMX WERE
SIMILAR TO WHAT IS EXPECTED ACROSS THE REST OF THE AREA THIS
AFTERNOON. WITH THEIR QUICK TEMP DROP AND LIGHT WINDS...THEY HAVEN/T
EXPERIENCED ANY FOG AT THIS POINT...BUT THE ICE ACCRETION ALGORITHM
DID INDICATE SOME ICE ACCUMULATION. THIS IS LIKELY DUE TO THAT QUICK
DROP AND IN TURN SOME QUICK/HARD FROST ON THE SENSOR. IT WILL BE
INTERESTING TO SEE IF ANY VERY SHALLOW FOG DEVELOPS AT KCMX OVER
THE NEXT COUPLE HOURS...AS IT WILL FORESHADOW WHAT WILL OCCUR
TONIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 332 PM EST THU DEC 18 2014
NAM SHOWS A 500 MB RIDGE OVER THE LOWER GREAT LAKES 00Z SAT WITH A
CLOSED LOW OVER WESTERN ONTARIO. THE LOW DOES NOT MOVE MUCH ON
SATURDAY...BUT THE UPPER LEVEL TROUGH ASSOCIATED WITH THIS LOW MOVES
INTO THE UPPER GREAT LAKES AND THIS TROUGH REMAINS OVER THE UPPER
GREAT LAKES ON SUNDAY. LOOKS LIKE THE TROUGH REMAINS TO THE WEST AND
THE SYSTEM SNOW REMAINS TO THE WEST OF THE AREA AND WILL KEEP THE
FORECAST DRY FOR NOW. DID NOT MAKE TOO MANY CHANGES TO THE GOING
FORECAST.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE PLAINS
12Z MON AND THE TROUGH MOVES INTO THE UPPER GREAT LAKES 12Z TUE. THE
TROUGH AND LOW MOVES OVER THE UPPER GREAT LAKES 12Z WED AND THE
TROUGH MOVES INTO EASTERN CANADA ON THU. TEMPERATURES LOOK TO BE
NEAR NORMAL THIS FORECAST PERIOD AND LOOKS LIKE THE SURFACE LOW GOES
FAR ENOUGH SOUTH FOR THE MAJORITY OF THE PCPN WITH LAKE ENHANCED
SNOW FOR MOST OF THIS FORECAST PERIOD. WILL GO WITH CHANCE POPS
THROUGH THIS FORECAST AND KEEP THE PCPN AS SNOW EXCEPT NEAR THE
GREAT LAKES SHORELINES. WILL HAVE TO WATCH THIS SYSTEM FOR MON INTO
WED AS THE TRACK IS STILL UNCERTAIN AND THE TRACK WILL DETERMINE THE
PCPN TYPE. SIGNALS ARE THERE FOR A WINTER STORM SOMEWHERE IN THE
GREAT LAKES REGION AND WILL MENTION THIS IN THE HWO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1251 PM EST THU DEC 18 2014
ONLY SCATTERED CLOUDS TODAY...BUT THERE IS POTENTIAL FOR VERY
SHALLOW FOG TONIGHT. BEST CHANCES FOR FOG IS AT KCMX...SO SHOWED A
DROP OF VIS. HOWEVER...WAS NOT CONFIDENT ENOUGH TO DROP CIGS AT THIS
TIME. IF FOG DOES DEVELOP...CONDITIONS WILL IMPROVE FRIDAY MORNING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 403 AM EST THU DEC 18 2014
HIGH PRESSURE BUILDING INTO THE UPPER GREAT LAKES REGION TODAY AND
TONIGHT WILL DIMINISH THE NORTHERLY WINDS BELOW 15KTS. THE HIGH
WILL BEGIN TO SHIFT TO THE EAST OF THE REGION ON FRIDAY AND ALLOW
WINDS TO GRADUALLY TURN TO THE SOUTH THROUGH FRIDAY NIGHT. A NEARLY
STATIONARY TROUGH IN THE LEE OF THE NORTHERN ROCKIES THIS WEEKEND
WILL KEEP THE SOUTH TO SOUTHWESTERLY WINDS IN PLACE AND GENERALLY
UNDER 20KTS. THIS TROUGH WILL GIVE WAY TO A DEVELOPING LOW THAT
WILL MOVE INTO THE NORTHERN PLAINS SUNDAY NIGHT AND THE UPPER
MISSISSIPPI VALLEY ON MONDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...07
AVIATION...TITUS
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1255 PM EST THU DEC 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM EST THU DEC 18 2014
AN UPPER RIDGE STRETCHING FROM MINNESOTA THROUGH NORTHWEST ONTARIO
WILL BE THE MAIN FEATURE CONTROLLING THE WEATHER OVER THE UPPER
GREAT LAKES REGION OVER THE NEXT 24 HOURS. BENEATH THIS UPPER
RIDGE...A 1029MB SURFACE HIGH SITS JUST TO THE NORTH OF THE
MINNESOTA WHILE THE SURFACE TROUGH THAT LED TO THE SNOW YESTERDAY
IS OVER NORTHERN LAKE MICHIGAN AND NORTHERN LOWER MICHIGAN AND
WEAKENING. NORTH-NORTHEASTERLY FLOW AROUND THIS HIGH HAS PULLED
DRIER AIR INTO THE UPPER GREAT LAKES REGION...LEADING TO CLEARING
SKIES THIS PAST EVENING OVER MUCH OF LAKE SUPERIOR. BUT MOISTURE
TRAPPED BELOW THE SUBSIDENCE INVERSION...AND COMBINED WITH UPSLOPE
FLOW...HAS LED TO LOW CLOUDS PERSISTING OVER A GOOD PORTION OF
UPPER MICHIGAN EARLY THIS MORNING. THERE ARE A COUPLE SPOTS WHERE
THE CLOUDS DID CLEAR OUT...GENERALLY OVER THE KEWEENAW PENINSULA
AND ALSO IT/S STARTING TO OVER THE EAST. WHERE SKIES CLEARED
OUT...3AM TEMPERATURES ARE IN THE SINGLE DIGITS ABOVE ZERO (6
DEGREES AT KCMX)...WHILE THE CLOUDS HAVE KEPT THE TEMPERATURES IN
THE UPPER TEENS AND LOWER 20S ELSEWHERE. STILL SEEING LIGHT
FLURRIES HERE AT OUR OFFICE AT 330AM...SO WILL CONTINUE TO MENTION
ISOLATED FLURRIES IN THE FORECAST FOR THE UPSLOPE LOCATIONS THROUGH
DAYBREAK.
WITH THE UPPER RIDGE AND SURFACE HIGH MOVING OVER THE AREA
TODAY...EXPECT CONTINUED QUIET CONDITIONS FOR THE SHORT TERM
PERIOD. THERE ARE TWO AREAS OF FOCUS IN THE SHORT TERM
PERIOD...FIRST THE LOW CLOUDS AND THEIR DIMINISHMENT AND THEN THE
POTENTIAL FOR SOME FREEZING FOG OVERNIGHT TONIGHT. FOR THE LOW
CLOUDS...KMQT VWP INDICATES CLOUD TOPS AROUND 2.5KFT...WHICH
MATCHES UP WELL WITH THE INVERSION INDICATED ON THE MODELS AT
900MB. THE BIG QUESTION IS WHEN WILL THEY DISSIPATE TODAY. AT
THIS TIME OF THE YEAR WITH THE LOW SUN ANGLE AND LIMITED
MIXING...THERE IS LITTLE DAY TIME HELP AND WILL NEED TO RELY ON THE
ADVECTION OF DRIER AIR INTO THE AREA. UNFORTUNATELY...THIS IS WHERE
THE MODELS TEND TO DIFFER. THE 00Z NAM HOLDS ONTO THE CLOUDS FOR
MUCH OF THE DAY AND EVEN THROUGH THE NIGHT TONIGHT...BUT THINK THAT
IS LARGELY TIED TO IT TRADITIONALLY OVER DOING LOW LEVEL MOISTURE.
THAT APPEARS TO THE CASE EARLY THIS MORNING...WHERE IT HAS THE LOW
CLOUDS JUST TO THE WEST OF JAMES BAY BEING MUCH FARTHER TO THE
SOUTH AND SUPPOSEDLY ENTERING NORTHERN LAKE SUPERIOR AT THIS TIME.
THE RECENT RAP (ALONG WITH THE HRRR) RUNS ALSO HOLD ONTO THE CLOUDS
FOR MUCH OF THE DAY BEFORE CLEARING THEM OUT THIS AFTERNOON...BUT IT
APPEARS TO HAVE THE LOW LEVEL MOISTURE FARTHER NORTH OVER LAKE
SUPERIOR THAN WHAT IS ACTUALLY OCCURRING. THE MORE OPTIMISTIC
RUNS...WHICH SEEM TO HAVE A BETTER HANDLE ON THE LOCATION OF THE
LOW CLOUDS ARE THE 00Z GFS/ECMWF. THEY HOLD ONTO THE LOW CLOUDS
OVER THE NORTH CENTRAL AND WEST FOR THE FIRST PART OF THE MORNING
AND THEN SCATTER THEM OUT THROUGH THE LATER PART OF THE MORNING AND
EARLY AFTERNOON. WILL FOLLOW THAT IDEA AT THIS POINT FOR THE CLOUD
COVER FORECAST FOR TODAY. MEANWHILE OVER THE EAST...THE ADVECTION
OF THE DRIER AIR AND LITTLE UPSLOPE HELP SHOULD ALLOW THE LOW
CLOUDS TO DISSIPATE DURING THE FIRST PART OF THE MORNING. THAT DRY
AIR HAS ALREADY SCATTERED THE CLOUDS OUT OVER LUCE COUNTY AND
STARTING TO SEE IT WORK INTO ALGER/SCHOOLCRAFT COUNTIES. AS FOR
HIGHS TODAY...EXPECT THEM TO BE IN THE MID-UPPER 20S OVER MUCH OF
THE AREA.
FOLLOWING THE IDEA OF THE CLOUDS DIMINISHING TODAY...WOULD EXPECT A
VERY GOOD RADIATIONAL COOLING NIGHT TONIGHT UNDER THE CENTER OF THE
HIGH. THUS...WILL CONTINUE THE IDEA OF GOING AT OR BELOW THE
COLDEST GUIDANCE. THE GEM MODELS USUALLY PERFORM WELL IN
RADIATIONAL COOLING NIGHTS AND THEY HAVE LOWS IN THE LOWER SINGLE
DIGITS WHERE THEY ARE NOT INDICATING CLOUDS (ALTHOUGH THE REGIONAL
GEM REDEVELOPS LOW CLOUDS OVER THE HIGHER TERRAIN OF THE NORTH
CENTRAL TONIGHT). THUS...HAVE LOWS IN THE SINGLE DIGITS ABOVE ZERO
TO AROUND ZERO OVER THE INTERIOR LOCATIONS. WITH KCMX DROPPING TO 6
DEGREES AT 3AM THIS MORNING...THAT SUPPORTS TO EXPECTATIONS FOR
TONIGHT. THIS EXPECTED DROP IN TEMPS WILL LEAD TO THE POTENTIAL FOR
PATCHY FREEZING FOG OR AT LEAST SOME SOLID FROST. WITH DEWPOINTS IN
THE MID-UPPER TEENS TODAY...TEMPS SHOULD EASILY DROP THROUGH THOSE
VALUES THIS EVENING. DEWPOINTS THIS PAST EVENING AT KCMX WERE
SIMILAR TO WHAT IS EXPECTED ACROSS THE REST OF THE AREA THIS
AFTERNOON. WITH THEIR QUICK TEMP DROP AND LIGHT WINDS...THEY HAVEN/T
EXPERIENCED ANY FOG AT THIS POINT...BUT THE ICE ACCRETION ALGORITHM
DID INDICATE SOME ICE ACCUMULATION. THIS IS LIKELY DUE TO THAT QUICK
DROP AND IN TURN SOME QUICK/HARD FROST ON THE SENSOR. IT WILL BE
INTERESTING TO SEE IF ANY VERY SHALLOW FOG DEVELOPS AT KCMX OVER
THE NEXT COUPLE HOURS...AS IT WILL FORESHADOW WHAT WILL OCCUR
TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 514 AM EST THU DEC 18 2014
FRIDAY...A DRY AIRMASS ASSOCIATED WITH THE DEPARTING AREA OF
HIGH PRESSURE WILL LEAVE PARTLY TO MOSTLY SUNNY SKIES ACROSS UPPER
MICHIGAN. HOWEVER...THERE IS SOME UNCERTAINTY WHETHER MOISTURE
BENEATH THE PROMINENT 925 MB INVERSION WILL LINGER ENOUGH FOR MOSTLY
CLOUDY SKIES...ESPECIALLY OVER THE WEST. EVEN WITH SOME
CLOUDS...TEMPS ARE EXPECTED TO CLIMB INTO THE UPPER 20S.
FRI NIGHT...TEMPS SHOULD DROP OFF QUICKLY IN THE EVENING BUT MAY
REBOUND LATE AS CLOUDS INCREASE WITH STRENGTHENING 850 MB WAA AND
ASSOCIATED 280K ISENTROPIC ASCENT. WITH THE MID LEVEL REMAINING
DRY...NO PCPN IS EXPECTED.
SAT...AS THE SFC HIGH SLOWLY BUILDS INTO THE ERN LAKES...SRLY WINDS
WILL BRING WARMER AIR INTO THE REGION WITH TEMPS CLIMBING SLIGHTLY
ABOVE NORMAL WITH MAX READINGS CLIMB TO AROUND 30 DESPITE THE
THICKENING CLOUDS.
SUN...AS A MID LEVEL TROUGH DEVELOPS ACROSS THE CENTRAL CONUS...THE
MODELS SUGGEST POTENTIAL FOR A WEAK SHORTWAVE AND AREA OF MORE
SUBSTANTIAL 290K ISENTROPIC LIFT THAT COULD PRODUCE SOME LIGHT SNOW.
THE DYNAMICS REMAIN WEAK ENOUGH TO SUPPORT ONLY SLIGHT CHANCE POPS.
CONTINUED WAA WILL NUDGE MAX TEMPS INTO THE LOWER 30S.
MON-WED...ALTHOUGH THERE IS GENERAL MODEL AGREEMENT THAT A MID LEVEL
TROUGH WILL DEEPEN OVER THE NORTHERN GREAT LAKES...THERE ARE
CONSIDERABLE DIFFERENCES IN THE DETAILS OF HOW THE SHORTWAVES DIVING
INTO THE TROUGH WILL INTERACT AND HOW THAT WILL INFLUENCE
THE POSITION/STRENGTH OF THE SFC FEATURES. SNOW CHANCES INCREASE
FROM MON INTO MON NIGHT AS THE INITIAL LOW MOVES THROUGH THE UPPER MS
VALLEY. ENOUGH WARM AIR MAY BE DRAWN NORTHWARD TO BRING POTENTIAL FOR
SOME RAIN INTO THE EAST HALF. THE PREFERRED/MORE CONSISTENT 00Z/12Z
ECMWF KEEP THE LOW AND WARMER AIR SLIGHTLY FARTHER TO THE
SOUTH...MINIMIZING CHANCES FOR RAIN. THE LARGER DISPARITIES DEVELOP
BY WED WITH THE HANDLING OF A STRONGER SHRTWV THAT WOULD SUPPORT
RAPID DEEPENING OF THE SFC LOW. THE 18Z/00Z GFS AND 00Z ECMWF HAVE
BACKED OFF FROM THE VERY STRONG LOW MOVING INTO THE CNTRL LAKE AND
THEN NORTHWARD TOWARD JAMES BAY AND HAVE SHIFTED THE STRONGER LOW
THROUGH THE NORTHEAST CONUS. HOWEVER...IT WOULD NOT BE SURPRISING TO
SEE THE MODELS REVERT BACK TO THE STRONGER LOW THROUGH LOWER MI. WITH
SO MUCH UNCERTAINTY AND HIGH ENSEMBLE/MODEL SPREAD...THE FCST
MAINTAINS HIGHER END SNOW CHANCES BUT WITH LESS EMPHASIS FOR NOW ON
THE POTENTIAL FOR HEAVY SNOW AND HIGH WINDS UNTIL FCST CONFIDENCE IS
HIGHER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1251 PM EST THU DEC 18 2014
ONLY SCATTERED CLOUDS TODAY...BUT THERE IS POTENTIAL FOR VERY
SHALLOW FOG TONIGHT. BEST CHANCES FOR FOG IS AT KCMX...SO SHOWED A
DROP OF VIS. HOWEVER...WAS NOT CONFIDENT ENOUGH TO DROP CIGS AT THIS
TIME. IF FOG DOES DEVELOP...CONDITIONS WILL IMPROVE FRIDAY MORNING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 403 AM EST THU DEC 18 2014
HIGH PRESSURE BUILDING INTO THE UPPER GREAT LAKES REGION TODAY AND
TONIGHT WILL DIMINISH THE NORTHERLY WINDS BELOW 15KTS. THE HIGH
WILL BEGIN TO SHIFT TO THE EAST OF THE REGION ON FRIDAY AND ALLOW
WINDS TO GRADUALLY TURN TO THE SOUTH THROUGH FRIDAY NIGHT. A NEARLY
STATIONARY TROUGH IN THE LEE OF THE NORTHERN ROCKIES THIS WEEKEND
WILL KEEP THE SOUTH TO SOUTHWESTERLY WINDS IN PLACE AND GENERALLY
UNDER 20KTS. THIS TROUGH WILL GIVE WAY TO A DEVELOPING LOW THAT
WILL MOVE INTO THE NORTHERN PLAINS SUNDAY NIGHT AND THE UPPER
MISSISSIPPI VALLEY ON MONDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...TITUS
MARINE...SRF
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1132 AM CST THU DEC 18 2014
.UPDATE...
ISSUED AT 959 AM CST THU DEC 18 2014
CLOUD TRENDS THE MAIN ISSUE TODAY. AREA OF MID CLOUDS AND THEN
LOWER MVFR CLOUDS ADVANCING NORTHEAST EAST OF THE UPPER TROUGH
OVER WRN ND. THIS WILL CONTINUE TO SPREAD EAST INTO THIS AFTN.
ALSO GOT A FAST MOVING AREA OF LOWER STRATOCU MOVING NORTH-
NORTHWEST FROM WISCONSIN INTO NE-ECNTRL MN AND ITS HEADED TOWARD
OUR EASTERN COUNTIES SO INCREASED CLOUD COVER THERE. ALSO QUITE A
BIT OF FLURRIES IN THIS CLOUD AREA...SO MATCHED UP WITH WFO DLH
AND INCLUDED FLURRIES THIS AFTN IN THE FAR EASTERN FCST AREA. KEPT
FLURRIES IN FAR WEST BUT HAVENT SEEN ANY SIGNS OF PRECIP IN CNTRL
ND.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 314 AM CST THU DEC 18 2014
MAIN ISSUE TODAY WILL BE CLOUDS MOVING INTO THE WEST AND IF WE GET
ANY SNOW OF MENTION OR JUST FLURRIES.
A WEAK UPPER SHORTWAVE TROUGH IS SEEN ON WV LOOP ROTATING OVER THE
MT/ND BORDER...AND THAT FEATURE WILL MOVE INTO THE EASTERN DAKOTAS
TODAY. THIS WILL HELP BRING SOME FAIRLY WEAK SYNOPTIC LIFT INTO THE
REGION. THE SFC HIGH WILL MOVE OFF TO THE EAST...ALLOWING SOUTH
WINDS AND MORE MOISTURE TO MOVE BACK INTO THE AREA. THERE HAS BEEN
A DECENT BAND OF SNOW OVER CENTRAL ND...WHICH MATCHES PRETTY WELL
WHERE THE RAP HAS SOME Q VECTOR CONVERGENCE COINCIDING WITH
FRONTOGENESIS. THE RAP HAS THIS FEATURE WEAKENING SIGNIFICANTLY AS
IT MOVES EAST INTO OUR CWA LATER THIS MORNING...SO THINK A WELL
DEFINED BAND OF SNOW IS NOT TOO LIKELY. HOWEVER...SOME VERY LIGHT
SNOW IS NOT OUT OF THE QUESTION. INCLUDED SOME LOW POPS IN THE FAR
WEST WITH SOME FLURRIES GRADUALLY MOVING TOWARDS THE RED RIVER AS
CLOUDS CONTINUE TO INCREASE THROUGHOUT THE DAY IN THE WESTERN
COUNTIES. TEMPS TODAY SHOULD BE A BIT WARMER EVEN WITH CLOUDS AS
TEMPS UNDER THE CLOUDS ARE ALREADY CLOSE TO 20 DEGREES OUT WEST.
WILL CONTINUE TO KEEP HIGHS IN THE UPPER TEENS TO 20S.
TONIGHT...THE WEAK UPPER TROUGH CONTINUES OVER THE NORTHERN
PLAINS...WITH WARM AIR ADVECTION CONTINUING THROUGHOUT THE NIGHT.
CLOUDS WILL CONTINUE TO MOVE INTO THE AREA AND THAT ALONG WITH THE
SOUTH WINDS WILL PREVENT TEMPS FROM BOTTOMING OUT TONIGHT. TEMPS
SHOULD STAY MAINLY IN THE TEENS. THE WARM AIR ADVECTION WILL
CONTINUE INTO FRIDAY...ALLOWING TEMPS TO GET WELL INTO THE 20S TO
NEAR 30 IN THE SOUTH. MODELS CONTINUE TO SHOW SOME VERY LIGHT
PRECIP AS ISENTROPIC LIFT CONTINUES AND CONDENSATION PRESSURE
DEFICITS BECOME MORE FAVORABLE...MAINLY IN THE NORTHEASTERN
COUNTIES. WILL CONTINUE TO KEEP 20 POPS GOING FOR LIGHT SNOW...BUT
THINK THAT ANY ACCUMULATION WILL BE VERY LIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 314 AM CST THU DEC 18 2014
FRIDAY NIGHT THROUGH SATURDAY NIGHT...THE WEAK UPPER TROUGH
LINGERS OVER NORTHERN MN...AND THE NEXT SHORTWAVE TROUGH BEGINS TO
APPROACH FROM THE WEST. SOUTH WINDS WILL CONTINUE AND MOISTURE
SHOULD BE INCREASING. THERE CONTINUE TO BE SOME SIGNS OF PRECIP
MOVING IN WITH THAT SECOND SHORTWAVE LATE SATURDAY INTO SATURDAY
NIGHT. THERE IS A LOT OF VARIATION FROM THE NAM SHOWING UP TO A
TENTH OF AN INCH TO THE ECMWF HAVING HARDLY ANYTHING...SO KEPT
POPS LOW FOR NOW. THE SREF SHOWS SOME FZRA PROBABILITIES FOR
SATURDAY NIGHT...BUT THE TOP DOWN METHOD GIVES MOSTLY SNOW IN THE
NORTH WHERE POPS ARE LOCATED WITH THE WARM LAYER ALOFT STAYING
MOSTLY IN OUR SOUTH WHERE CURRENTLY WE ARE GOING DRY. WILL KEEP A
CLOSE EYE ON THE SITUATION. TEMPS WILL BE ABOVE AVERAGE WITH HIGHS
PUSHING 30 DEGREES AND LOWS STAYING IN THE TEENS TO EVEN LOW 20S.
FOR SUNDAY THROUGH WEDNESDAY...UPPER PATTERN SHIFTS A BIT BECOMING
MORE OF A NW FLOW REGIME WITH THE RIDGE AXIS OVER THE INTERMOUNTAIN
WEST. HOWEVER...THE MAIN JET ENERGY IS EXPECTED TO REMAIN WEST AND
SOUTH OF THE AREA. A FEW WAVES PUSHING ACROSS THE AREA WILL BRING
CHANCES FOR LIGHT PCPN...WHILE TEMPERATURES CONTINUE TO REMAIN NEAR
OR SLIGHTLY ABOVE NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1112 AM CST THU DEC 18 2014
AS HIGH PRESSURE DRIFTS EAST...THE AREA WILL SEE LIGHT S TO SE
WINDS CONTINUE THROUGH THE NEXT 24 HRS. BASED ON THE LATEST
TRENDS AND MODEL DATA...LOWER MVFR TO IFR CIGS WILL BE INCREASING
OVER MUCH OF THE AREA OVER THE NEXT 6-12 HRS. THE NAM MOS DATA
SUPPORT CIGS BELOW 1000 FT...WITH NAM BUFR SOUNDINGS SATURATED IN
THE LOW LEVES AS WELL. SOME CIGS MAY DIP BELOW 500 FT BY LATE
TOMORROW MORNING ACCORDING TO THE NAM MOS. HAVE NOT INCLUDED CIGS
THIS LOW YET...BUT WILL NEED TO MONITOR TRENDS AND MODEL DATA TO
SEE IF THE LIKELIHOOD INCREASES.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...JR
LONG TERM...JR/HOPKINS
AVIATION...KNUTSVIG
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
345 PM EST THU DEC 18 2014
.SYNOPSIS...
A WEAKENING UPPER LEVEL DISTURBANCE MOVING THROUGH THE OHIO VALLEY
WILL RESULT IN A FEW SNOW FLURRIES OR SNOW SHOWERS THIS EVENING.
WEAK SURFACE HIGH PRESSURE WILL THEN PUSH SLOWLY EAST ACROSS THE
REGION THROUGH THE WEEKEND...LEADING TO PRIMARILY DRY CONDITIONS
AND NEAR NORMAL TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
UPR LVL S/WV WILL PASS EAST ACRS OUR REGION THROUGH THIS EVENING.
FORCING IS WEAK WITH MOST AREAS JUST SEEING A FEW FLURRIES. THERE
COULD BE A FEW SNOW SHOWERS WITH JUST A LIGHT DUSTING ALONG THE
I-70 CORRIDOR WHERE DEEPEST MOISTURE WILL INTERSECT WEAK FORCING.
LOW LEVEL CLOUDS WILL CONTINUE TO BE AN ISSUE AS THE RAP MODEL
SHOWS REGION STAYING PRETTY MUCH OVERCAST OVERNIGHT. LOWS WILL
DROP INTO THE LOWER AND MID 20S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
WEAK SFC HIGH PRESSURE WILL SLOWLY BUILD INTO THE AREA ON FRIDAY.
DESPITE THIS FEATURE...IT LOOKS LIKE LOW LEVEL MOISTURE WILL HANG
AROUND AS IT BECOMES TRAPPED UNDERNEATH THE HIGH. WILL CONTINUE
WITH MAINLY CLOUDY SKIES. HIGHS WILL RANGE FROM THE LOWER TO MID
30S.
FOR FRIDAY NIGHT INTO SATURDAY...LATEST MODEL FORECASTS KEEP THE
AFFECTS OF AN UPR LVL S/WV TO OUR SOUTH WHILE SFC RIDGING REMAINS
IN PLACE. IT IS DIFFICULT TO KNOW IF THE LOW LEVEL CLOUDS WILL
ERODE DURING THIS TIME FRAME. HOWEVER...WITH AN INCREASE IN MID
AND HIGH LEVEL MOISTURE...IT WILL LIKELY REMAIN MOSTLY CLOUDY. IT
WILL BE A LITTLE WARMER ON SATURDAY WITH HIGHS IN THE MID AND
UPPER 30S.
BY SATURDAY NIGHT...HIGH PRESSURE WILL CONTINUE TO EXTEND ACROSS
THE GREAT LAKES AND OHIO VALLEY WHILE A WEAK UPR LVL S/WV PASSES
ACRS THE SOUTHERN GREAT LAKES. PARTLY CLOUDY SKIES ARE EXPECTED.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE CENTERED TO THE NORTHEAST WILL BRING DRY WEATHER ON
SUNDAY. INCREASING MOISTURE AND LIFT WELL AHEAD OF DEVELOPING LOW
PRESSURE MAY PRODUCE LIGHT RAIN AND SNOW ON MONDAY. AS THE LOW MOVES
TO LAKE MICHIGAN ON TUESDAY...RAIN WILL BE LIKELY IN A CONCENTRATED
BAND OF ISENTROPIC LIFT EXTENDING SOUTHEAST FROM THE LOW CENTER.
ENERGY WILL TRANSFER TO A COASTAL LOW ON WEDNESDAY...LEAVING THE
AREA IN A BRISK AND COLDER NORTHWEST FLOW OF DECREASING MOISTURE AND
FORCING. THIS WILL BRING AN END TO STEADY RAIN AND SNOW...WITH
SCATTERED SNOW SHOWERS THEN LINGERING INTO THURSDAY. NORTHERN
LOCATIONS SEEM TO HAVE THE BEST CHANCE FOR LIGHT SNOW ACCUMULATIONS.
AFTER NEAR NORMAL HIGHS AROUND 40 ON SUNDAY...WARM ADVECTION AHEAD
OF THE LOW WILL ALLOW ABOVE NORMAL HIGHS IN THE 40S ON MONDAY AND
TUESDAY. EXPECT EARLY HIGHS NEAR 40 ON WEDNESDAY...DROPPING TO
BELOW NORMAL 30S UNDER COLD ADVECTION ON THURSDAY.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
PERSISTENT MVFR CLOUD DECK CONTINUES TO REMAIN IN PLACE ACRS THE
TAFS EARLY THIS AFTN. WEAKENING MID LEVEL S/W TRACKING THRU THE
OHIO VALLEY WILL RESULT IN SNOW SHOWERS AND FLURRIES WITH THE BEST
COVERAGE ACRS KDAY/KCMH/KLCK. MVFR VSBYS POSSIBLE AT THESE TAF
SITES BUT SINCE PROBABILITY AND DURATION WILL BE LIMITED HAVE JUST
MENTIONED -SN. THERE MAY BE SOME IMPROVEMENT TO CIGS ESPECIALLY AT
KCVG/KLUK AFTER THE PASSAGE OF THIS S/W FOR A BRIEF PERIOD. HAVE
FOLLOWED SOLN CLOSER TO LATEST RAP BRINGING MVFR CIGS BACK OR A LTL
LOWER THIS EVENING. HAVE SHOWN IMPROVEMENT TO VFR AT KCVG/KLUK
FRIDAY AFTN WITH MVFR CIGS HOLDING AT THE REMAINDER OF THE TAF SITES.
NW TO W WINDS OF UNDER 10 KNOTS ARE EXPECTED THROUGH THE FCST
PERIOD.
OUTLOOK...MVFR CEILINGS MAY CONTINUE INTO FRIDAY. MVFR CEILINGS
AND VISIBILITIES ARE POSSIBLE ON SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...CONIGLIO
AVIATION...AR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1247 PM EST THU DEC 18 2014
.SYNOPSIS...
A WEAKENING UPPER LEVEL DISTURBANCE MOVING THROUGH THE OHIO VALLEY
WILL LEAD TO A FEW SNOW FLURRIES THIS AFTERNOON INTO THIS EVENING.
WEAK SURFACE HIGH PRESSURE WILL THEN PUSH SLOWLY EAST ACROSS THE
REGION THROUGH THE WEEKEND...LEADING TO PRIMARILY DRY CONDITIONS
AND NEAR NORMAL TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MID LEVEL SHORTWAVE TO TRACK FROM THE CENTRAL PLAINS EAST ACROSS
THE OHIO VALLEY TODAY. GOOD DEAL OF LOW CLOUDS REMAIN IN PLACE
THIS MORNING. 12Z ILN SOUNDING SHOWS THIS SHALLOW MOISTURE TRAPPED
BELOW AN INVERSION AROUND 880 MB. EVEN WITH SOME EROSION OF THESE
LOW CLOUDS...MID LEVEL CLOUDS ASSOCIATED WITH THE AFOREMENTIONED
S/W WILL OVERSPREAD THE REGION. THIS S/W WILL DAMPEN AND WEAKEN
AS IT PASSES THRU THE OHIO VALLEY. NUMERICAL MODELS SUGGEST
WEAK LIFT IN THE MID LEVELS DEVELOPING EARLY AFTERNOON.
EXPECT THIS TO RESULT IN SOME FLURRIES OR EVEN SOME ISOLD SNOW
SHOWER ACTIVITY. HAVE CONTINUED WITH JUST A CHANCE OF FLURRIES
THIS AFTERNOON. GIVEN THE COMBINATION OF THE CLOUDS AND MAINLY
NEUTRAL LOW LEVEL TEMPERATURE ADVECTION THROUGH THE DAY...
EXPECT A SMALL DIURNAL RISE TO READINGS TODAY. HAVE HIGHS FROM THE
LOWER 30S NORTH TO THE MID 30S SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
WE COULD SEE A FEW FLURRIES LINGER INTO THIS EVENING...BUT FOR THE
MOST PART EXPECT DRY CONDITIONS TONIGHT THROUGH FRIDAY AS A WEAK
AREA OF HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES REGION. THE
MODELS CONTINUE TO TREND FARTHER SOUTH WITH THE LOW PRESSURE
SYSTEM MOVING THROUGH THE SOUTHEASTERN UNITED STATES FRIDAY NIGHT
INTO SATURDAY. WITH THE BETTER FORCING GENERALLY REMAINING TO OUR
SOUTHEAST...WILL TRIM BACK POPS AND JUST ALLOW FOR A TOKEN SLIGHT
CHANCE INTO OUR FAR SOUTHEAST THROUGH THE DAY ON SATURDAY. WITH
THIS FARTHER SOUTH SOLUTION...WE WOULD BE COLD ENOUGH FOR ANY PCPN
TO BE ALL SNOW. FAIRLY SEASONABLE TEMPERATURES ARE EXPECTED THROUGH THE
END OF THE WEEK...WITH HIGHS BOTH FRIDAY AND SATURDAY IN THE MID TO
UPPER 30S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRESSURE AND A COOL AIRMASS SHOULD ALLOW DRY WEATHER ON
SUNDAY. LIGHT PRECIP WILL BE POSSIBLE MONDAY EXTENDING FROM A
TROUGH ALONG THE EAST COAST.
WE MAY BEGIN TO FEEL THE EFFECTS OF A POWERFUL LOW PRESSURE SYSTEM
ON TUESDAY. HAVE LESS THAN AVERAGE AMOUNT OF CONFIDENCE DUE TO MODEL
DIFFERENCES FROM RUN TO RUN. AT THIS POINT IT APPEARS THE LOW WILL
DEVELOP OVER THE SOUTHERN PLAINS ON TUESDAY...BEFORE LIFTING THROUGH
OHIO TO THE GREAT LAKES ON WEDNESDAY. THE LOW MAY FEATURE A VERY
TIGHT PRESSURE GRADIENT SURROUNDING ITS DEEP CENTER...PRODUCING
STRONG WINDS. COPIOUS MOISTURE FEEDING FROM THE TROPICS AND FROM THE
ATLANTIC OCEAN COULD ADVECT AROUND THE LOW. CURRENT TEMPERATURE
FORECAST ALLOWS RAIN TUESDAY INTO WEDNESDAY...CHANGING TO SNOW LATER
WEDNESDAY AS COLDER AIR WRAPS IN BEHIND THE LOW.
TEMPERATURES WILL BE RELATIVELY CLOSE TO NORMAL FOR THE MOST PART.
HIGHS WILL BE A COUPLE DEGREES WARMER FOR SUNDAY AND MONDAY UNDER
NEUTRAL TO WEAK WARM ADVECTION. READINGS ON TUESDAY AND WEDNESDAY
WILL BE DEPENDENT ON THE POSITION OF THE ANTICIPATED STRONG LOW.
WARM ADVECTION AHEAD OF THE LOW COULD BRING HIGHS UP INTO THE MID
40S ON TUESDAY...OR EVEN HIGHER IF THE WARMER MEX GUIDANCE
VERIFIES. HIGHS COULD SLIP TO AROUND 40 ON WEDNESDAY IN COLD
ADVECTION BEHIND THE LOW.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
PERSISTENT MVFR CLOUD DECK CONTINUES TO REMAIN IN PLACE ACRS THE
TAFS EARLY THIS AFTN. WEAKENING MID LEVEL S/W TRACKING THRU THE
OHIO VALLEY WILL RESULT IN SNOW SHOWERS AND FLURRIES WITH THE BEST
COVERAGE ACRS KDAY/KCMH/KLCK. MVFR VSBYS POSSIBLE AT THESE TAF
SITES BUT SINCE PROBABILITY AND DURATION WILL BE LIMITED HAVE JUST
MENTIONED -SN. THERE MAY BE SOME IMPROVEMENT TO CIGS ESPECIALLY AT
KCVG/KLUK AFTER THE PASSAGE OF THIS S/W FOR A BRIEF PERIOD. HAVE
FOLLOWED SOLN CLOSER TO LATEST RAP BRINGING MVFR CIGS BACK OR A LTL
LOWER THIS EVENING. HAVE SHOWN IMPROVEMENT TO VFR AT KCVG/KLUK
FRIDAY AFTN WITH MVFR CIGS HOLDING AT THE REMAINDER OF THE TAF SITES.
NW TO W WINDS OF UNDER 10 KNOTS ARE EXPECTED THROUGH THE FCST
PERIOD.
OUTLOOK...MVFR CEILINGS MAY CONTINUE INTO FRIDAY. MVFR CEILINGS
AND VISIBILITIES ARE POSSIBLE ON SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL/AR
SHORT TERM...JGL
LONG TERM...CONIGLIO
AVIATION...AR
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
312 PM EST THU DEC 18 2014
.SHORT TERM...RADAR SHOWS SOME PATCHY LIGHT RAIN OR DRIZZLE WILL
BE MOVING ACROSS THE AREA FOR THE NEXT FEW HOURS...BUT THIS SHOULD
EXIT BY 00Z AND WILL CARRY NO POPS AFTER THAT TIME. THE QUESTION
OVERNIGHT WILL BE WHETHER CLOUDS ARE ABLE TO ERODE AS MUCH AS THE
GFS SAYS THEY WILL...OR IF THEY WILL HANG IN THROUGH MOST OF THE
NIGHT AS SHOWN BY THE NAM. WILL LEAN TOWARD THE NAM AS UPSTREAM
SATELLITE DOES NOT LOOK PROMISING FOR CLEARING ANY TIME SOON...AND
THE RAP LOOKS CLOSER TO THE NAM. WILL ALSO LEAN TEMPS ON THE WARM
SIDE OF MOS TONIGHT. THERE SHOULD BE SOME SUN ACROSS MOST OF THE
AREA BY MORNING...THEN HIGH CLOUDS BEGIN TO INCREASE FROM THE SW
AHEAD OF SOUTHERN STREAM VORT MAX AND JET STREAK. HIGH TEMPS SHOULD
REACH A CATEGORY OR TWO HIGHER THAN TODAY. ANY PRECIP WITH THIS
SYSTEM SHOULD HOLD OFF UNTIL AFTER THE END OF THE SHORT TERM
PERIOD.
.LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)...A FAST MOVING SYSTEM
THAT IS FORECAST TO FORM ALONG THE GULF COAST FRIDAY WILL MOVE FROM
THE LOWER MS VALLEY INTO THE EASTERN TENNESSEE VALLEY OVERNIGHT
FRIDAY NIGHT INTO SATURDAY MORNING. THE BULK OF THE SYSTEM WILL BE
SOUTH OF TN AND AFFECT THE SOUTHEASTERN STATES INTO THE CAROLINAS.
TEMPERATURES WILL DROP INTO THE 30S FRIDAY EVENING AND AREAS TO THE
NORTH OF INTERSTATE 40...ESPECIALLY IN THE HIGHER ELEVATIONS COULD
SEE SOME SNOW LATE FRIDAY NIGHT AND EARLY SATURDAY. LOWS WILL ONLY
DROP TO NEAR FREEZING SO AMOUNTS ARE EXPECTED TO BE LIGHT...LESS
THAN ONE INCH. TEMPERATURES SATURDAY WILL WARM ABOVE FREEZING TO
THE 40S TO NEAR 50. WEAK HIGH PRESSURE BUILDS BACK IN SATURDAY
NIGHT AND SUNDAY WITH SKIES BECOMING PARTLY SUNNY.
SUNDAY NIGHT THROUGH LATE TUESDAY PATTERN CONTINUES TO BE UNSETTLED.
UPPER TROUGH OVER THE CENTRAL STATES WILL HELP ANOTHER SYSTEM
DEVELOP OVER THE NORTHERN PLAINS AND A NEW SYSTEM ALSO DEVELOPS
ALONG THE GULF COAST. THE SOUTHERN SYSTEM WILL AFFECT THE FORECAST
AREA FIRST WITH A CHANCE OF RAIN SUNDAY NIGHT AND MONDAY. THIS
SYSTEM PULLS OUT AND THEN THE STRONGER SECOND SYSTEM WILL MOVE
INTO THE OHIO AND TN VALLEYS MONDAY NIGHT AND TUESDAY. THIS SYSTEM
IS EXPECTED TO FORM AN UPPER LOW OVER THE MID MS VALLEY TUESDAY AND
THEN SLOWLY MOVE EAST INTO THE EASTERN GREAT LAKE STATES THROUGH
WEDNESDAY. COLDER AIR ON THE BACK SIDE OF THE SYSTEM WILL LOWER
TEMPERATURES WEDNESDAY AND THURSDAY. ALSO THE SYSTEM IS EXPECTED TO
DEEPEN MORE. SNOW SHOWERS WILL LIKELY AFFECT THE NORTHERN PARTS OF
THE AREA WEDNESDAY AND WEDNESDAY NIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 33 49 37 50 / 0 10 70 70
KNOXVILLE MCGHEE TYSON AIRPORT, TN 29 47 34 46 / 10 0 50 50
OAK RIDGE, TN 30 47 34 46 / 0 0 50 40
TRI CITIES AIRPORT, TN 28 46 30 43 / 10 0 30 50
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS/TD
AREA FORECAST DISCUSSION
NWS AMARILLO TX
248 PM CST THU DEC 18 2014
.DISCUSSION...
PRIMARY WEATHER IMPACTS DURING THE NEXT SEVEN DAYS WILL BE IN THE
SHORT TERM WITH PRECIPITATION CHANCES TONIGHT AND POTENTIAL FOR FOG
ONCE AGAIN. MAIN ADJUSTMENT TO THE FORECAST WAS TO TRY AND BE MORE
DETERMINISTIC WITH PRECIPITATION TYPE OVERNIGHT ALTHOUGH THAT
REMAINS A CHALLENGE GIVEN MARGINAL THERMAL PROFILES FOR FROZEN
PRECIPITATION IN MODEL FORECAST SOUNDINGS. INITIAL CONCERNS ARE FOG
POTENTIAL LATER TONIGHT AS LOW LEVEL FLOW BECOMES MORE EASTERLY AND
STRENGTHENS. MOISTURE OVER SOUTHWEST OKLAHOMA AND WESTERN NORTH
TEXAS WILL ADVECT WESTWARD AND UPSLOPE. HAVE INCLUDED AREAS OF FOG
IN THE GRIDS. LOCALLY DENSE FOG WILL AGAIN BE POSSIBLE.
WV LOOP AND 500 MB RAP ANALYSIS CLEARLY SHOWED A SHORTWAVE TROUGH
OVER EASTERN ARIZONA MOVING EASTWARD. SHORT TERM MODELS ARE IN GOOD
AGREEMENT ON THE TIMING AND STRENGTH OF THIS WAVE AS IT MOVES TOWARD
WEST TEXAS TONIGHT AND CROSSES THE REGION TOMORROW MORNING. THE
PERIOD OF BEST OMEGA/SATURATION IN THE DEDRITIC GROWTH ZONE WILL BE
AFTER ABOUT 03Z IN THE WEST SPREADING EASTWARD OVERNIGHT AND LASTING
THROUGH ABOUT 15Z IN THE EAST. JUST BELOW THE DGZ IS A LAYER OF DRY
AIR THAT WILL TAKE SOME TIME TO SATURATE THUS DELAYING THE ONSET OF
PRECIPITATION UNTIL CLOSER TO MIDNIGHT IN THE WEST/CENTRAL AND AFTER
MIDNIGHT IN THE EAST. THE BIGGEST CHALLENGE FOR CONVEYING SENSIBLE
WEATHER IN THIS FORECAST WILL BE THE TEMPERATURE PROFILE. AT LEAST
SHORT RANGE MODELS AGREES FAIRLY WELL. THE DEPTH OF THE ABOVE
FREEZING WET BULB TEMPERATURES IS SUFFICIENT FOR ALL RAIN ACROSS
MOST OF THE AREA...ESPECIALLY THE FAR SOUTHEAST. HAVE TRENDED
PRECIPITATION TYPE TO MORE RAIN AS A RESULT. INCREASED QPF SLIGHTLY
IN THE FAR SOUTHEAST.
QUITE A BIT OF UNCERTAINTY DEVELOPS BY EARLY NEXT WEEK AND CONTINUES
THROUGHOUT THE EXTENDED PERIOD. VERY POWERFUL PACIFIC JET NOSES INTO
THE CENTRAL ROCKIES BY MONDAY EAST OF A SIGNIFICANT MEAN RIDGE OVER
THE EASTERN PACIFIC. A VERY STRONG TROUGH HAS BEEN SHOWN TO DEVELOP
OVER THE EASTERN UNITED STATES. THIS SHOULD HAPPEN BY AROUND
CHRISTMAS EVE OR CHRISTMAS DAY BUT MEDIUM RANGE MODELS STRUGGLE WITH
HOW IT EVOLVES EARLY/MID WEEK ONCE PACIFIC JET MOVES INTO THE
CENTRAL CONUS. NEW 12Z EMCWF IS QUICKER WITH DEVELOPING A CLOSED LOW
WHILE THE GFS IS MORE PRONOUNCED WITH INDIVIDUAL SHORTWAVES
TRAVERSING THE DEEPENING UPPER TROUGH. THE GFS BECOMES DEEPER BY
WEDNESDAY WITH MORE SUBSTANTIAL HEIGHT RISES ON ITS WEST SIDE OVER
THE PLAINS. EXACT IMPLICATIONS FOR US ARE UNCLEAR. WILL NEED TO
WATCH THE POTENTIAL FOR A DOWNSLOPING WARMING/WIND EVENT ON MONDAY.
GFS/MEX DEPICT THIS NOW. ECMWF IS MORE EXPANSIVE WITH HEIGHT FALLS
OVER THE CENTRAL CONUS GIVEN ITS MORE CONSOLIDATED/SPRAWLING
SOLUTION WITH LESS DISTINCT SHORTWAVES EMBEDDED WITHIN. GFS
SOUNDINGS SHOW DEEP MIXING INTO AN AREA OF STRONG FLOW ALOFT WHICH
RAISES SOME CONCERN OF NEAR ADVISORY CRITERIA WINDS IF THIS SOLUTION
VERIFIES. OTHERWISE DID NOT DEVIATE FROM MEDIUM RANGE CONSENSUS. ANY
PRECIPITATION IN THE EXTENDED SHOULD BE INSIGNIFICANT...AND
DIFFICULT TO TIME GIVEN MODEL DIFFERENCES.
BRB
.PREV DISCUSSION... /ISSUED 1142 AM CST THU DEC 18 2014/
.AVIATION...
FOR THE 18Z TAFS...THE MAIN WEATHER ELEMENTS FOR THIS FCST CYCLE WILL
BE LOW CLOUDS AND EPISODES OF FOG. FOG IS SLOWLY ERODING AT THE TAF
SITES AND SHOULD CONTINUE TO DO SO EARLY THIS AFTERNOON. IFR CIGS
WILL GRADUALY AND TEMPORARILY LIFT INTO THE MVFR CATEGORY AS WELL.
EXPECT THE RETURN OF IFR CIGS AND AREAS OF FOG AGAIN LATE TONIGHT
INTO FRIDAY MORNING. A FAST MOVING UPPER LEVEL STORM SYSTEM WILL
GRAZE THE REGION TONIGHT AND EARLY FRIDAY...AND MAY BRING SOME
SPRINKLES...LIGHT RAIN SHOWERS...FLURRIES...OR VERY LIGHT SNOW.
HOWEVER...THE CHANCE OF PRECIPITATION IS NOT VERY HIGH...SO HAVE
OPTED TO OMIT FROM THE TERMINAL FCSTS AT THIS TIME.
ANDRADE
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 33 43 29 55 28 / 20 20 5 0 5
BEAVER OK 29 45 28 52 30 / 10 20 5 0 5
BOISE CITY OK 26 49 24 53 22 / 10 5 5 0 0
BORGER TX 33 44 31 53 30 / 20 20 5 0 5
BOYS RANCH TX 31 49 27 56 25 / 20 10 5 0 0
CANYON TX 33 45 29 57 27 / 30 20 5 0 5
CLARENDON TX 35 41 33 54 34 / 30 30 5 0 5
DALHART TX 27 49 23 53 21 / 20 10 0 0 0
GUYMON OK 29 48 26 54 26 / 10 10 5 0 5
HEREFORD TX 32 51 27 58 26 / 30 20 5 0 5
LIPSCOMB TX 32 43 30 51 35 / 10 20 5 0 5
PAMPA TX 32 41 32 50 32 / 20 30 5 0 5
SHAMROCK TX 35 41 35 49 36 / 20 30 5 0 10
WELLINGTON TX 37 42 35 49 38 / 20 40 5 5 10
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
02/17