Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/24/14
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
814 PM CST TUE DEC 23 2014
.DISCUSSION...
MOISTURE CHANNEL IMAGERY REVEALS THE LOCATION OF THE MID LEVEL
TROUGH QUITE EASILY AS IT ROTATES THROUGH THE CENTRAL AND SOUTHERN
PLAINS. ANOTHER ROUND OF RAIN IS EXPECTED OVER MAINLY THE EASTERN
HALF OF THE STATE TONIGHT AS THE TROUGH LIFTS THROUGH. STILL
LOOKING AT A LITTLE MIX ON THE TAIL END OF THE SYSTEM AS IT PULLS
OUT BUT LITTLE IF ANY ACCUMULATION EXPECTED.
FORECAST IN GOOD SHAPE BUT WEATHER/POP GRIDS WERE REWORKED TO
REFLECT CURRENT TRENDS AND HRRR SOLUTION. ALL OTHER FORECAST
ELEMENTS LEFT AS IS AND ALL UPDATES ARE OUT.
&&
.PREV DISCUSSION... /ISSUED 556 PM CST TUE DEC 23 2014/
AVIATION...
AN UPPER TROUGH REMAINS JUST WEST OF ARKANSAS THIS EVENING. CLOUDS
WILL CONTINUE ACROSS THE AREA AND CEILINGS WILL LOWER OVERNIGHT.
RAIN CHANCES WILL ALSO INCREASE OVERNIGHT AND CONTINUE INTO
WEDNESDAY MORNING. CLOUDS COULD BREAK UP LATE IN THE PERIOD. LIFR
TO MVFR CONDITIONS ARE MAINLY EXPECTED.
PREV DISCUSSION... /ISSUED 255 PM CST TUE DEC 23 2014/
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
UPR LVL TROF RMND SITUATED TO THE W OF AR THIS AFTN. THIS RESULTING
SWLY FLOW ALOFT WAS BRINGING ANOTHER SHRTWV THRU THE FA WITH ASSOCD
RAINFALL NOW WORKING ACRS CNTRL AR. SUBSIDENCE BEHIND THE SHRTWV HAS
RESULTED IN SOME BINOVC OVR PARTS OF WRN AR AT MID AFTN.
MEANWHILE...CDFNT WAS LOCATED WELL E OF THE AREA WITH N/NWLY WINDS
ALLOWING COOLER AIR TO ADVECT INTO THE STATE.
THE AFOREMENTIONED SHRTWV WL CONT TO LIFT NEWD OUT OF THE AREA THIS
EVENING. ANTICIPATE A LULL IN THE PRECIP THIS EVENING AND PLAN TO
ADJUST EVENING POPS BASED ON RADAR TRENDS. BY LATER TNGT AND ON
WED...THE MAIN UPR TROF WL SHIFT EWD THRU THE MID SOUTH. ANOTHER
ROUND OF RAIN WL ACCOMPANY THIS SYS...WITH THE HIGHEST POPS
MENTIONED FOR THE ERN HALF OF THE FA.
RAIN CHCS WL DIMINISH FM THE SW ON WED AS THE UPR LVL SYS AND ASSOCD
SFC LOW LIFT NEWD AWAY FM THE FA. CURRENT FCST TRENDS STILL LOOK
GOOD INDCG SMALL POPS ACRS NRN AR WED AFTN. ONE CONCERN STILL
LINGERS REGARDING THE CHC OF SOME WET SNOW ACRS PARTS OF WRN AND NRN
AR LATE TNGT AND WED MRNG AS COLDER AIR ALOFT /ASSOCD WITH THE UPR
TROF/ MOVES OVR THE AREA. MODEL DATA CONT TO SHOW THAT SFC TEMPS WL
STAY ABV FRZG IN MOST LOCATIONS FOR MUCH IN THE WAY OF ANY SNOW
ACCUMULATION. HOWEVER...SOME OF THE HIGHER ELEVATIONS COULD SEE A
BURST OF WET SNOW BEFORE ENDING...WITH POSSIBLY SOME MINOR
ACCUMULATION ON GRASSY SURFACES.
THE STORM SYS WL CONT TO PULL AWAY FM THE REGION WED NGT AND THU...
WITH DRIER CONDS RETURNING. THIS WL BE SHORT LIVED THOUGH AS YET
ANOTHER FAST MOVG STORM SYS WL BRING RAIN CHCS BACK THE NATURAL
STATE FRI AND FRI NGT.
LONG TERM...SATURDAY THROUGH TUESDAY
ON SATURDAY A STORM SYSTEM AND COLD FRONT WILL BE MOVING THROUGH THE
REGION...AND FORECAST HAS A GOOD CHANCE OF RAIN. MAINLY A SHOWER
EVENT...WHILE THE GFS CONTINUES TO BE FASTER THEN THE EURO. HAVE
TRENDED TO THE SLOWER EURO AND KEEP MORE PRECIP OVER AR THROUGH
SUNDAY...THEN THE PRECIP GRADUALLY MOVING OUT OF AR LATER SUNDAY.
THE UPPER LOW PRESSURE TROUGH LAGS THE SURFACE SYSTEM AND HENCE
HOLDING OF THE PRECIP ON SUNDAY BEFORE MOVING EAST. IN THE OVERNIGHT
AND EARLY MORNING PERIODS...SOME LOW CHANCES OF A WINTRY MIX WILL BE
POSSIBLE...MAINLY OVER WEST CENTRAL...TO THE NORTHERN HALF OF
AR...AS TEMPS LOWER TO AROUND THE FREEZING MARK. LITTLE TO NO
SIGNIFICANT AMOUNTS ARE EXPECTED. DRY AND COOL MONDAY...BUT SOME
CLOUDS WILL STILL BE SEEN UNTIL THE UPPER TROUGH TOTALLY EXISTS
EAST. TUESDAY MAY SEE A REINFORCING SHOT OF COLD AIR BUT SOME
UNCERTAINTY DOES EXIST IN THE FORECAST THIS FAR OUT IN THE FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 38 44 31 51 / 60 40 10 0
CAMDEN AR 38 47 31 56 / 50 20 0 0
HARRISON AR 34 39 28 51 / 30 40 10 0
HOT SPRINGS AR 37 45 30 54 / 40 20 0 0
LITTLE ROCK AR 39 46 31 53 / 50 20 0 0
MONTICELLO AR 41 47 33 54 / 60 20 0 0
MOUNT IDA AR 35 43 28 54 / 30 20 0 0
MOUNTAIN HOME AR 36 41 29 51 / 40 40 10 0
NEWPORT AR 39 45 31 51 / 60 40 10 0
PINE BLUFF AR 40 47 32 53 / 60 20 0 0
RUSSELLVILLE AR 37 44 28 53 / 40 20 0 0
SEARCY AR 39 45 29 51 / 60 30 10 0
STUTTGART AR 40 46 31 52 / 60 30 0 0
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
56
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1036 PM MST SUN DEC 21 2014
.UPDATE...
ISSUED AT 831 PM MST SUN DEC 21 2014
ANOTHER UPDATE TO RAISE POPS OVER THE ERN PLAINS WHERE PERSISTENT
LIGHT BANDED RAIN SHOWERS HAVE BEEN MOVING...ALTHOUGH MOST OF THE
PRECIP NOT LIKELY REACHING THE GROUND. ALSO BUMPED UP POPS FOR THE
NRN SAN LUIS VALLEY WHERE PERSISTENT LIGHT SNOW HAS BEEN FALLING.
LATEST HRRR SHOWS PRECIP DIMINISHING FOR THE PLAINS EARLY MON
MORNING. ROSE
UPDATE ISSUED AT 544 PM MST SUN DEC 21 2014
UPDATED GRIDS/ZONES PER LATEST OBS AND RADAR TRENDS AS WELL
AS LATEST HI RES GUIDANCE. MAIN CHANGES WERE TO BUMP UP POPS
SLIGHTLY OVER THE DVD SO THAT CATEGORICAL POPS ARE THERE FOR THE
HIGHER ELEVATIONS...AND ADDED BORDERLINE MENTIONABLE (10 PERCENT)
POPS FOR EL PASO COUNTY THIS EVE. LOOKS LIKE MOST OF THE PRECIP
WILL STAY OUT OVER KIOWA COUNTY...BUT CANNOT RULE OUT SOME SMALL
BANDS OF SHOWERS MOVING OVER THE I-25 CORRIDOR AS WELL. ROSE
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 320 PM MST SUN DEC 21 2014
...HEAVY SNOW TO CONTINUE IN THE MTNS...
CURRENTLY...
RADAR AND SFC OBS SHOW WIDESPREAD SNOW IN THE HIGH COUNTRY. KLXV
WEBCAMS SHOW SOME PRETTY DECENT ACCUMS IN TOWN. KGJT SHOWS
WIDESPREAD PRECIP ALONG THE WEST SLOPE MOVING RAPIDLY SE IN THE
STRONG NW FLOW ALOFT. AT LOWER ELEVATIONS...WIDESPREAD HIGH
CLOUDINESS DOMINATES ACROSS THE PLAINS. TEMPS WERE MILD WITH MAINLY
50S...WITH THE WARMEST TEMPS AT CANON CITY AND KSPD. GUSTY WINDS
PREVAILED IN THE MTNS AND GAP AREAS...WITH WINDS GUSTING TO 40 MPH
IN GAP AREAS.
TODAY THRU TONIGHT...
HEAVY WIND DRIVEN SNOW WILL CONTINUE ACROSS THE C MTNS AND NW SLOPES
OF THE LA GARITA MTNS. A FOOT OR MORE OF ADDITIONAL SNOW IS NEAR
CERTAIN.
OVER THE REMAINDER OF THE MTNS...SNOW OVER THE HIGH COUNTRY IS
EXPECTED TO GRADUALLY DROP SOUTHEAST WITH TIME...AND SNOW SHOULD BE
INCREASING MOST MTN AREAS AFTER MIDNIGHT. THE NORTHERN SAN LUIS
VALLEY SHOW START TO SEE SNOW DURING THE EARLY MORNING HOURS. A FEW
SNOW SHOWERS WILL BE POSSIBLE ON THE PLAINS...BUT NO SIGNIF ACCUMS
ARE ANTICIPATED.
AMBIENT TEMPS TONIGHT SHOULD REMAIN RELATIVELY MILD...WITH LOWS
IN THE U20S PLAINS...AND TEENS AND 20S MTNS. WITH THE STRONG WINDS
OVER THE HIGHER TERRAIN...WIND CHILLS WILL BE SHARPLY COLDER.
WINDS OVER THE MTNS WILL RANGE IN THE 30-50 MPH RANGE TONIGHT.
TOMORROW...
SNOW...HEAVY AT TIMES...WILL CONTINUE IN THE MTNS ALONG THE CONTDVD
AND NW FACING SLOPES OF THE LA GARITAS. SNOW WILL LIKELY SLACKEN
AS THE AFTERNOON PROGRESSES TOMORROW. WINDS WILL LESSEN A BIT OVER
THE HIGHER TRRN BUT WILL INCREASE ACROSS THE PLAINS BY AFTERNOON
AS THE STRONG JET MOVES OUT OVER THE MTNS AND LAPSE RATES INCREASE
AS COLDER AIR MOVE IN ALOFT. BY MIDAFTERNOON TOMORROW...LAPSE
RATES WILL INCREASE TO 8-9 C/KM AND THIS WILL ALLOW FOR CONVECTIVE
SNOW SHOWERS TO DEVELOP OVER THE PLAINS. THE BEST CHANCE OF SNOW
SHOWERS AT LOWER ELEVATIONS WILL BE OVER THE PALMER DIVIDE AND THE
EAST FACING SLOPES OF THE WETS/SANGRES AND RATON MESA/SPANISH
PEAKS REGIONS.
IT WILL BE COLDER TOMORROW OVER THE PLAINS...WITH TEMPS 10F OR SO
COLDER THAN TODAY. IT WILL FEEL MUCH COLDER AS THE WINDS INCREASE
FROM THE NW DURING THE AFTERNOON. HI TEMPS TOMORROW WILL LIKELY
OCCUR AROUND OR SHORTLY AFTER NOONTIME.
I CANNOT RULE OUT SOME SNOW BANDS DROPPING A COUPLE INCHES OF SNOW
ON THE PLAINS TOMORROW. HOWEVER...GUIDANCE HAS BEEN GRADUALLY
BACKING OFF ON THIS SCENARIO. WHERE THESE BANDS SET UP IS ANYONES
GUESS...BUT THE OVERALL BEST CHANCE OF ANY PRECIP AT THE LOWER
ELEVATIONS APPEARS TO BE ON THE PALMER DVD AND SPANISH PEAKS/RATON
MESA REGION (LAS ANIMAS/HUERFANO COUNTY REGION).
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 320 PM MST SUN DEC 21 2014
MONDAY NIGHT AND TUESDAY...THE UPPER LOW OVER THE MIDWEST MONDAY
NIGHT WILL SLIDE GRADUALLY TO THE NE TOWARDS THE GREAT
LAKES...ELONGATING THE UPPER TROUGH DOWN INTO TX TUE MORN. THIS WILL
ALLOW THE 140 KT UPPER JET TO DROP DOWN INTO WESTERN CO AND CREATE
VERY STRONG WINDS FOR THE FORECAST AREA. SO...ONGOING WINTER
HIGHLIGHTS WILL END MON EVE AND THE THREAT THEN BECOMES MORE OF A
WIND PROBLEM AS OPPOSED TO A SNOW ACCUMULATION PROBLEM. SNOW IS
EXPECTED TO LINGER OVER THE E PLAINS AND SOUTHERN FOOTHILLS THROUGH
TUE MORN...BUT VERY STRONG NORTHERLY WINDS TUE AFTN AND EVE ARE
EXPECTED...AND EVEN THOUGH AIR TEMP SHOULD BE IN THE MID TO UPPER
30S...WIND CHILLS WILL BE IN THE TEENS TO EVEN SINGLE DIGITS.
TUESDAY NIGHT AND WEDNESDAY...THIS STILL LOOKS TO BE A TRANSITIONAL
DAY AS NORTHERLY FLOW BECOMES MORE WESTERLY THROUGH WED AFTN AHEAD
OF THE NEXT APPROACHING SYSTEM. TEMPS ARE EXPECTED TO REBOUND INTO
THE MID TO UPPER 40S FOR THE PLAINS...AND INTO THE UPPER 30S TO 40S
FOR THE HIGH VALLEYS.
THURSDAY THROUGH SUNDAY...MODELS ARE HAVING A HARD TIME COMING UP
WITH A SOLUTION FOR CHRISTMAS AND THE WEEKEND. BOTH EC AND GFS ARE
INDICATING ANOTHER TROUGH MOVING IN...BUT KEEPING MUCH OF THE
ACTIVITY TO THE NORTH. IT LOOKS LIKE THE CONTDVD AND ESPECIALLY THE
CENTRAL MTS ARE SET UP TO GET SOME MORE SNOW STARTING VERY EARLY THU
MORNING AND LASTING THROUGH FRI...THOUGH THE EC ALSO SHOWS SOME PCPN
WITH A COLD FRONT PASSAGE FOR THE PLAINS LATE THU. FEEL THAT IS
HIGHLY SUSPECT...SO EVEN THOUGH ISOLATED POPS ARE INCLUDED FOR THE
PALMER DVD AND EL PASO COUNTY...KEPT MUCH OF THE E PLAINS DRY.
CLOUDY AND A BIT WINDY...BUT DRY. EXPECT A RATHER MILD DAY ON THU
AHEAD OF THIS SYSTEM...THEN 15 TO 20 DEGREES COLDER ON FRI. AS FOR
SAT AND SUN...MODEL DISAGREEMENT CONTINUES...THOUGH A GENERAL
WESTERLY FLOW ALOFT LOOKS TO BE IN PLACE THROUGH SUN. FEEL THE BEST
BET IS TO INCLUDE ISOLATED POPS FOR THE HIGHER ELEVATIONS ON SUN
WITH A GRADUAL WARMING TREND THROUGH THE WEEKEND. MOORE
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1033 PM MST SUN DEC 21 2014
SCT SHRASN WILL TEMPORARILY WIND DOWN AFTER ABOUT 09Z TONIGHT.
ANOTHER ROUND OF SCT SHOWERS IS EXPECTED MON AFTERNOON AND
LASTING THROUGH MON EVENING. IT WILL BE SPOTTY IN NATURE...BUT
COULD RESULT IN BRIEF MVFR CONDITIONS FOR THE TERMINALS. OTHER
CONCERN WILL BE INCREASING N WINDS ON THE BACK SIDE OF THIS
SYSTEM. COULD SEE SOME GUSTS IN THE 30 KT RANGE MON EVENING
FOR KCOS AND KPUB. THE CENTRAL MTS WILL CONTINUE TO SEE HEAVY
SN THROUGH THE PERIOD...WITH SN AND BLSN OVER THE DVD ESPECIALLY
N OF KMYP. ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 PM MST MONDAY FOR COZ064-066.
WINTER WEATHER ADVISORY UNTIL 11 PM MST MONDAY FOR COZ061.
WINTER STORM WARNING UNTIL 11 PM MST MONDAY FOR COZ058>060.
&&
$$
UPDATE...ROSE
SHORT TERM...HODANISH
LONG TERM...MOORE
AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
926 PM MST SUN DEC 21 2014
.UPDATE...
ISSUED AT 847 PM MST SUN DEC 21 2014
SHOWERS HAVE ALSO MANAGED TO SPILL ACROSS THE FRONT RANGE AS
INSTABILITY HAS INCREASED THIS EVENING. THERE MAY BE SOME
POTENTIAL INSTABILITY WITH DRYING NOTED ALOFT...AND CELLS HAVE
BECOME QUITE CONVECTIVE WITH ISOLATED LIGHTNING INDICATED IN THE
COLORADO LIGHTNING MAPPING ARRAY. MEANWHILE...FRONT IS MOVING
ACROSS THE CO/WY BORDER AS OF 830 PM WITH ANOTHER AREA OF
PRECIPITATION...MOSTLY SNOW...BEHIND IT. HAVE INCREASED POPS FOR
MOST OF THE PLAINS TO ACCOUNT FOR BOTH OF THESE FEATURES. SHORT
RANGE RAP AND HRRR ARE NOT HANDLING THIS PRECIPITATION WELL AT
ALL. A FEW SPOTS COULD SEE AN INCH OR TWO OF SNOW ON THE PLAINS
IF SHOWERS BECOME MORE PERSISTENT AS INTENSITY/CONVECTIVE
PARAMETER IS THERE.
UPDATE ISSUED AT 652 PM MST SUN DEC 21 2014
BAND OF SHOWERS IS ORGANIZING ON THE EASTERN PLAINS EARLY THIS
EVENING...FROM NEAR CHEYENNE TO FORT MORGAN AND EAST OF LIMON.
THIS FEATURE SEEMS RATHER SLOW MOVING. MOST OF THIS WILL BE RAIN
BEFORE COLD FRONT ARRIVES LATER IN THE EVENING. THE ARRIVAL OF
THIS FEATURE AND A MORE NORTHERLY LOW LEVEL COMPONENT COULD SHIFT
THE BAND BACK TOWARD THE I-25 CORRIDOR OVERNIGHT...BUT STILL
FAVORING LOCATIONS EAST OF I-25. MOUNTAIN HEAVY SNOW EVENT IS
UNDERWAY WITH MOSTLY 3-6 INCH AMOUNTS BUT A FEW SPOTS ALREADY
APPROACHING A FOOT TOWARD THE COLUMBINE AND TOWER SNOTELS...AND
ALSO NEAR COPPER MOUNTAIN. THE HEAVIEST SNOW IS STILL ON TRACK TO
OCCUR THIS EVENING BUT THERE WAS SOME DRYING NOTED ON THE RIVERTON
WYOMING SOUNDING BETWEEN 700 MB AND 500 MB...WHICH SHOULD RESULT
IN LOWER SNOW INTENSITY AFTER MIDNIGHT. UNTIL THEN...ONE HALF TO
ONE INCH PER HOUR SNOW AMOUNTS WILL CONTINUE OVER MOST OF THE HIGH
COUNTRY. HAZARDOUS AND SLOW DRIVING CONDITIONS WILL REMAIN IN
PLACE THROUGH MONDAY WITH CONTINUED WINTER STORM WARNING.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 326 PM MST SUN DEC 21 2014
SNOW WILL CONTINUE IN THE MOUNTAINS OVERNIGHT TAPERING OFF
STARTING MONDAY EVENING. UPSTREAM OBS SHOW VISIBILITIES REDUCING
DOWN TO HALF A MILE WITH THE HEAVIER SNOW. CURRENT WARNING
PRODUCTS STILL ON TRACK BUT OVERNIGHT SHIFTS MAY NEED TO RE-ASSESS
END TIMES DUE TO RECENT MODEL RUNS MOVING THE JET OUT SOONER. THE
LINGERING MOISTURE AND OROGRAPHIC FLOW WILL STILL PRODUCE SOME
SNOW SHOWERS OVER THE MOUNTAINS TOMORROW BUT THE INTENSITY WILL
DECREASE. CONTINUING TO URGE TRAVELERS TO USE CAUTION AS WINDS
OVER THE HIGHER MOUNTAIN PASSES WILL GUST UP TO 60 MPH THIS
EVENING. CONSIDERABLE BLOWING AND DRIFTING SNOW ALONG WITH
VISIBILITIES BELOW A QUARTER OF A MILE WILL OCCUR OVER AREAS SUCH
AS LOVELAND PASS...BERTHOUD PASS AND RABBIT EARS PASS. OTHER WELL
TRAVELED AREAS ALONG I-70 SUCH AS THE TUNNEL WILL ALSO SEE GREATLY
REDUCED VISIBILITIES WITH ICY AND SNOWY ROADWAYS. TRAVELERS ARE
URGED TO USE CAUTION AND DELAY PLANS TO TRAVEL OVER THE MOUNTAINS
THIS EVENING IF AT ALL POSSIBLE.
FOR THE PLAINS DOWNSLOPING WINDS WILL KEEP AREAS ALONG THE
FOOTHILLS 4-5 DEGREES WARMER AND DRY WITH WINDS GUSTING UP TO 60
MPH OVER THE WIND PRONE AREAS. WINDS WILL MOVE TO A MORE NORTHERLY
DIRECTION EARLY TOMORROW MORNING BRINGING COOLER CONDITIONS ALONG
WITH A CHANCE OF SNOW EAST OF I-25. IN ADDITION TO THE INFLUX OF
MOISTURE OVER THE PLAINS THERE IS SOME INSTABILITY SO SOME AREAS
COULD HAVE SOME LIGHT ACCUMULATION...WITH UP TO 2 INCHES POSSIBLE
UNDER THE HEAVIER BANDS. TEMPERATURES FOR TOMORROW WILL BE COOLER
WITH HIGHS ONLY GETTING INTO THE LOWER 40S FOR THE PLAINS AND 20S
FOR THE MOUNTAINS. BOTH THE NAM AND GFS ARE SHOWING INCREASED
WINDS OVER THE NE PLAINS STARTING TOMORROW AFTERNOON. GFS
CURRENTLY HAS 65KTS AT 700 MB THAT COULD TRANSLATE TO WARNING
CRITERIA. WILL CONSULT WITH THE NEXT SHIFT AND FUTURE MODEL RUNS
ON POSSIBLE ISSUANCE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 326 PM MST SUN DEC 21 2014
NORTHEAST COLORADO REMAINS UNDER THE INFLUENCE OF A BROAD UPPER
LEVEL TROUGH CENTERED OVER NEBRASKA AND A STRONG AND COLD NWLY
FLOW MONDAY NIGHT. BANDS OF INSTABILITY AND MOISTURE MOVING DOWN
THE WEST SIDE OF THIS TROUGH SHOULD KEEP SKIES MOSTLY
CLOUDY/OVERCAST AND SNOW CHANCES IN THE FORECAST FOR THE HIGH
PLAINS OVERNIGHT. HOWEVER AREAS ALONG THE BASE OF THE FRONT RANGE
MAY ESCAPE FROM ANY SNOWFALL DUE TO THE DRYING EFFECTS OF
DOWNSLOPE FLOW OFF THE FOOTHILLS AND CHEYENNE RIDGE. IN THE HIGH
COUNTRY...SNOWFALL WILL LIKELY CONTINUE OVERNIGHT...WITH MODERATE
SNOWFALL AT TIMES ON THE HIGHER RIDGES AND NORTHWEST FACING SLOPES
ALONG THE CONTINENTAL DIVIDE. GUSTY NORTHWEST WINDS MAY ALSO
CONTINUE TO PRODUCE SOME BLOWING SNOW IN OPEN TERRAIN. WITH
SNOWFALL LETTING UP AFTER MIDNIGHT...THE WINTER STORM WARNING FOR
MTN ZONES 31...33 AND 34 WILL BE ALLOWED TO EXPIRE AT MIDNIGHT
MST. MEANWHILE STRONG NWLY FLOW ALOFT GRADUALLY MIXES DOWNWARD
OVERNIGHT AS COLD ADVECTION INCREASES. BY EARLY TUESDAY MORNING
MODELS INDICATE N-NWLY SFC WINDS GUSTING TO AROUND 40 MPH ACROSS
THE NORTHEAST CORNER OF THE STATE. WITH SEVERAL INCHES OF SNOW
COVERING THE GROUND OUT THAT WAY...GOOD BET WE/LL SEE SOME BLOWING
SNOW.
DURING THE DAY TUESDAY...MODELS SHOW THE UPPER TROUGH TRACKING
SLOWLY NEWRD AWAY FROM COLORADO WITH NLY FLOW OVER THE PLAINS
BECOMING EVEN STRONGER DURING THE DAY. MODEL WIND SPEEDS ACROSS
THE NERN CORNER IN THE 35-50KT RANGE FOR MUCH OF THE DAY.
BLOWING SNOW WILL BE A GOOD BET ESPECIALLY IN OPEN AREAS OF
LOGAN...WASHINGTON...SEDGWICK AND PHILLIPS COUNTIES WHERE SEVERAL
INCHES OF SNOW ON THE GROUND. NO HIGHLIGHTS AT THIS TIME...HOWEVER
A HIGH WIND WARNING MAY BE NECESSARY SHOULD LATER MODEL RUNS
INDICATE EVEN STRONGER WIND SPEEDS. AS FOR SNOWFALL...SHOULD SEE
AN END TO IT BY MORNING AT LOWER ELEVATION AND BY LATE AFTERNOON
IN THE HIGH COUNTRY WITH THE START OF WARMING AND DRYING ALOFT.
ON WEDNESDAY..LARGE UPPER RIDGE OVER THE GREAT BASIN NUDGES EASTWARD
OVER COLORADO CLEARING SKIES AND WARMING TEMPERATURES. COULD SEE AN
8-10DEG F WARMUP IN MOST AREAS ON WEDNESDAY. WEDNESDAY NIGHT UPPER
RIDGE SHIFTS EAST AS THE NEXT IN A SERIES OF LONG WAVE TROUGHS
SWEEPS OVER THE PACIFIC NORTHWEST. LATEST INDICATIONS...AND THEY ARE
IN BETTER AGREEMENT TODAY...SHOW THIS TROUGH TRACKING NEARLY DUE
EAST ACRS THE NORTHERN ROCKIES. MODELS SHOW THE SOUTH SIDE OF
THIS TROUGH BRUSHING NORTHERN COLORADO CHRISTMAS DAY. AS IT DOES
MTNS AND HIGH VALLEYS SHOULD SEE A SHOT OF SNOW AND GUSTY WINDS
WHILE THE PLAINS REMAIN MILD AND DRY WITH GUSTY DOWNSLOPE FLOW
OFF THE FRONT RANGE. AS THE TROUGH PASSES LATE ON THURSDAY...MODELS
SHOW A BAND OF LIGHT PRECIP ASSOCIATED WITH COLD FRONT SLIPPING
SOUTH ACROSS NORTHEAST COLORADO DURING THE EVENING HOURS. SOME
AREAS MAY SEE SNOWFALL...BUT ANY AMOUNTS SHOULD BE LIGHT. BY LATE
THAT NIGHT...DRYING SETS IN ON COLD AND GUSTY NWLY WINDS.
FRIDAY AND SATURDAY LOOK DRY BUT WITH BELOW AVERAGE TEMPERATURES.
&&
.AVIATION...(FOR THE TAFS THROUGH 06Z MONDAY EVENING)
ISSUED AT 926 PM MST SUN DEC 21 2014
STRONGER WINDS TO AROUND 35-40 KNOTS NOW NOTED WITH COLD FRONT
MOVING THROUGH GREELEY-FORT COLLINS AREA. WILL INCREASE THE NORTH
WINDS IN THE TAF WITH GUSTS TO AROUND 35 KNOTS FOR A BRIEF TIME
WITH COLD FRONT. STILL EXPECT RAIN RAIN SHOWERS WITH ILS LANDING
CONDITIONS TIL AROUND 05Z-06Z...THEN SNOW SHOWERS WITH IFR/MVFR
CEILINGS AND VISIBILITIES WITH SNOW SHOWERS. POTENTIAL FOR LOWER
VISIBILITIES OF ONE MILE OR LESS IF SHOWERS MAINTAIN THERE PRESENT
INTENSITY...WITH LOCAL SNOW ACCUMULATION UP TO AN INCH OR SO
POSSIBLE MAINLY ON GRASSY SURFACES. THOSE WOULD LIKELY BE ENDING
TOWARD 12Z AS DRIER AIR MOVES IN FROM THE NORTHWEST.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL MIDNIGHT MST MONDAY NIGHT FOR
COZ031>034.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST MONDAY NIGHT FOR
COZ030.
&&
$$
UPDATE...BARJENBRUCH
SHORT TERM...BOWEN
LONG TERM...BAKER
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS TAUNTON MA
659 PM EST TUE DEC 23 2014
.SYNOPSIS...
WEAK LOW PRESSURE PASSES OFFSHORE TONIGHT. A MUCH STRONGER STORM
TRACKING ACROSS THE GREAT LAKES WILL BRING HEAVY RAIN...GUSTY
WINDS AND MINOR COASTAL FLOODING WEDNESDAY INTO CHRISTMAS MORNING.
DRY WEATHER WITH ABOVE NORMAL TEMPERATURES WILL FOLLOW FROM
CHRISTMAS AFTERNOON INTO SAT. A COLD FRONT MAY BRING A FEW RAIN OR
SNOW SHOWERS SUNDAY. ANOTHER STORM MAY AFFECT US SUNDAY NIGHT
INTO MON...BUT IT COULD ALSO PASS WELL TO OUR SOUTH.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
700 PM UPDATE...NO MAJOR CHANGES TO THE ONGOING FORECAST THIS
EVENING. DID FIND IT INTERESTING THE 22Z RAP ATTEMPTS TO BRING A
BRIEF END TO THE MEASURABLE RAINFALL THIS EVENING.
MEANWHILE...OTHER NEAR TERM GUIDANCE...SUCH AS THE HRRR...IS EVEN
MORE AGGRESSIVE KEEPING MEASURABLE RAINFALL AROUND OUR REGION.
BASED ON OBS...SIDED MORE WITH THE RAP IDEA WHEN ADJUSTING POPS
FOR MEASURABLE RAINFALL THIS EVENING. THAT SAID...WE STILL EXPECT
MORE THAN A FEW POCKETS OF DRIZZLE THIS EVENING. SO NOT THINKING
IT WILL BE COMPLETELY DRY ACROSS SOUTHERN NEW ENGLAND THIS
EVENING.
ALSO MADE SOME TWEAKS TO TEMPERATURES OVER THE NEXT FEW HOURS.
THESE WILL BE TRICKY...WITH TEMPERATURES EXPECTED TO HOLD FAIRLY
STEADY MOST OF THE NIGHT...THEN SLOWLY RISE LATE TONIGHT. IN ANY
CASE...WARM ENOUGH TO NOT HAVE TO WORRY ABOUT ANY WINTRY
PRECIPITATION.
PREVIOUS DISCUSSION...
TWO AREAS OF SHOWERS ON RADAR ARE MOVING EAST-NORTHEAST...WITH
THE TRAILING EDGES MOVING EAST OF OUR AREA EARLY TONIGHT.
ADDITIONAL LIGHT SHOWERS AND CLOUDS/FOG/DRIZZLE SHOULD LINGER
THROUGH THE NIGHT AS THE LOW LEVEL EAST-NORTHEAST FLOW OFF THE
GULF OF MAINE CONTINUES. DEWPOINTS RANGE FROM THE MID 30S
NORTHWEST THROUGH THE 40S MOST AREAS...WHICH SHOULD SERVE AT A
LOWER BOUNDARY FOR MIN TEMPS. ACTUALLY TEMPERATURES SHOULD REMAIN
NEAR STEADY OVERNIGHT.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
UPPER RIDGE BUILDS TO HIGHER AMPLITUDE BUT SHIFTS EAST OF NEW
ENGLAND. DEEP TROUGH OVER THE PLAINS MOVES EAST. THIS BRINGS A
DEEP SOUTH-SOUTHWEST FLOW OVER THE EASTERN USA WITH A STRONG 150
KNOT UPPER JET DRIVING NORTH THROUGH IT. THIS WILL BRING AN
AIRMASS WITH PRECIPITABLE WATER VALUES OF 1.5" OR HIGHER...OVER 3
STD DEVIATIONS ABOVE NORMAL AND NEAR THE MAXIMUM HISTORICAL VALUE.
LOW LEVEL SOUTHWEST JET OF 50-65 KNOTS ARRIVES WEDNESDAY
AFTERNOON AND CONTINUES THROUGH WEDNESDAY NIGHT...THEN SHIFTS EAST
CHRISTMAS MORNING.
LOW PRESSURE LIFTS NORTH FROM THE GULF OF MEXICO TO THE GREAT
LAKES...THEN SWINGS A COLD FRONT TOWARD NEW ENGLAND. GOOD MODEL
AGREEMENT ON MOVEMENT OF THE FRONT...REACHING THE CONNECTICUT
VALLEY BY 12Z THURSDAY.
THIS SYSTEM WILL GENERATE GOOD LOW LEVEL LIFT...AND BY WEDNESDAY
NIGHT THE APPROACHING UPPER JET SHOULD SUPPORT LIFT FROM THE UPPER
PART OF THE STORM. COMBINE THIS WITH THE VERY HUMID AIRMASS...AND
WE SHOULD EXPECT PERIODS OF RAIN WEDNESDAY AND ESPECIALLY
WEDNESDAY NIGHT WITH SOME HEAVY DOWNPOURS. THIS SHOULD BRING AN
ADDITIONAL 1-2 INCHES OF RAIN. THE DYNAMICS MAY ALSO DRIVE SOME
ISOLATED THUNDER...WITH THE BEST CHANCE LATE WEDNESDAY NIGHT AHEAD
OF THE COLD FRONT.
CONCERNS...RAIN. THE AIRMASS HAS A HIGH RAINFALL POTENTIAL BUT MAY
NOT TAP ALL OF THAT POTENTIAL. HOWEVER THERE MAY BE SOME LOCALLY
HEAVIER DOWNPOURS THAT PUSH TOTALS IN A FEW SPOTS ABOVE 2 INCHES.
WITH OR WITHOUT THIS...THE AMOUNT OF RAIN MAY BE ENOUGH TO CAUSE
SOME URBAN/POOR DRAINAGE FLOODING. WE HAVE ISSUED A FLOOD WATCH
FOR MOST OF OUR AREA FOR LATE WEDNESDAY THROUGH THURSDAY MORNING.
CONCERNS...WIND...PER BUFKIT THE LOW LEVEL JET OF 55 TO 65 KNOTS
WILL REACH DOWN TO ABOUT 1000 FEET AGL. THIS WILL BE LOW ENOUGH TO
REACH THE HIGHER HILLTOPS AND MAY INCH CLOSER TO THE SURFACE. IT
IS FACING A STRONG TEMPERATURE INVERSION NEAR THE GROUND WHICH MAY
KEEP SOME OF THIS WIND ABOVE THE GROUND. HEAVY DOWNPOURS MAY
PROVIDE A CHANNEL TO BRING SOME OF THAT WIND DOWN THE FINAL
THOUSAND FEET TO THE SURFACE. IN ANY CASE...WE EXPECT SOME GUSTY
SOUTH WINDS WEDNESDAY AFTERNOON THROUGH 12Z THURSDAY WITH VALUES
TO AT LEAST 30 KNOTS AND POSSIBLY APPROACHING 40 KNOTS.
CONCERNS...COASTAL FLOODING...ASTRONOMICAL TIDES WILL REMAIN HIGH
WITH A CONTINUED SOUTHEAST WIND ALONG THE MASS EAST COAST DURING
THE MORNING. MORE ON THIS IN THE COASTAL FLOOD SECTION.
WARM ADVECTION WEDNESDAY AFTERNOON WILL BRING WARMER TEMPERATURES
WITH VALUES REACHING THE 50S AND POSSIBLY REACHING 60 IN SOME
SPOTS. TEMPERATURES AND DEW POINTS WEDNESDAY NIGHT WILL NOT FALL
MUCH WITH VALUES LINGERING IN THE 50S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS...
* DRY AND WINDY CHRISTMAS AFTERNOON WITH GUSTS TO 45 MPH POSSIBLE
* CONTINUED DRY WITH ABOVE NORMAL TEMPERATURES FRI AND SAT
* A STORM MAY AFFECT THE REGION SUNDAY NIGHT INTO MON...BUT
CONFIDENCE IS LOW
OVERVIEW...
MODELS CONTINUE TO EXHIBIT GOOD OVERALL AGREEMENT INTO FRIDAY.
AFTER THAT TIME..THE ECMWF CONTINUES TO MAINTAIN A SHARPER MID
LEVEL TROUGH OVER THE CENTRAL USA, THIS TROUGH WOULD RESULT IN A
STORM TRACK CLOSER TO SOUTHERN NEW ENGLAND EARLY NEXT WEEK. THAT
SAID...JUST ABOUT ALL GUIDANCE IS INDICATING AT LEAST SOME
POTENTIAL FOR A PERIOD OF WET WEATHER EARLY NEXT WEEK. HAVE LOW
CONFIDENCE IN THE DETAILS OF STORM TRACK EARLY NEXT WEEK. WILL
KEEP A CHANCE OF SHOWERS IN THE FORECAST LATE SUNDAY INTO MONDAY
UNTIL THIS CRITICAL DETAIL CAN COME INTO BETTER FOCUS.
CHRISTMAS DAY...HEAVY RAIN WILL LIKELY BE ONGOING CHRISTMAS
MORNING ACROSS THE COASTAL PLAIN. RAIN THEN MOVES OUT BY MIDDAY
WITH SKIES BECOMING CLEARER IN THE AFTERNOON. GUSTY SOUTHWEST
WINDS IN THE MORNING NEAR THE COAST ASSOCIATED WITH THE LOW-LEVEL
JET AND HEAVIER RAINFALL. ALL AREAS WILL SEE STRONG WEST WIND
GUSTS IN THE AFTERNOON AS COLD ADVECTION DEVELOPS WITH STEEPENING
LOW LEVEL LAPSE RATES. WIND GUSTS TO 45 MPH WILL BE POSSIBLE AND
WIND ADVISORIES MAY BE NEEDED. MAX TEMPERATURES IN THE 50S TO NEAR
60 DEGREES WILL OCCUR IN THE MORNING...WITH TEMPS FALLING DURING
THE AFTERNOON.
FRIDAY INTO SAT...
HIGH PRESSURE CENTERED TO OUR SOUTH BRINGS DRY WEATHER WITH ABOVE
NORMAL TEMPERATURES. THE MILDER DAY WILL BE SATURDAY.
SUNDAY INTO TUESDAY...LOW CONFIDENCE FORECAST. A COLD FRONT MAY
BRING A FEW RAIN/SNOW SHOWERS SUNDAY. WE WILL THEN HAVE TO WATCH
FOR POSSIBLE FRONTAL WAVE SUNDAY NIGHT INTO MONDAY. THIS WAVE MAY
END UP TOO FAR SOUTH BUT WILL KEEP LOW POPS IN THE FORECAST. SOME
OF THE GUIDANCE...MOST NOTABLY THE ECMWF...KEEPS A LOW PRESSURE
NEAR OUR REGION INTO TUESDAY MORNING.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH WEDNESDAY NIGHT/...MODERATE CONFIDENCE.
TONIGHT...WITH MOIST EASTERLY FLOW...WE EXPECT CIGS TO REMAIN
MOSTLY BELOW 1000 FEET...WITH VSBYS MOSTLY 1 TO 3 MILES...THROUGH
THE NIGHT. CLOUDS/FOG/DRIZZLE THROUGH THE NIGHT.
WEDNESDAY AND WEDNESDAY NIGHT...IFR CONDITIONS CONTINUE IN
WIDESPREAD RAIN. LOCALLY HEAVY DOWNPOURS EXPECTED ESPECIALLY IN
THE AFTERNOON. INCREASING SOUTH WIND AT 1500-2000 FEET WITH SPEEDS
REACHING 50 KNOTS. THIS SHOULD CREATE LOW LEVEL WIND SHEAR BY THE
AFTERNOON AND THROUGH THE NIGHT.
KBOS TERMINAL...HIGH CONFIDENCE IN IFR CONDITIONS.
KBDL TERMINAL...MODERATE CONFIDENCE. MVFR CIGS SHOULD LOWER TO IFR
BUT TIMING UNCERTAIN.
OUTLOOK...THURSDAY THROUGH SUNDAY...
CHRISTMAS...MODERATE CONFIDENCE. IFR IN RAIN TO START...THEN
CONDITIONS IMPROVE TO VFR IN THE AFTERNOON FROM WEST TO EAST.
WEST WIND GUSTS TO 35-40 KT POSSIBLE IN THE AFTERNOON.
FRIDAY AND SATURDAY...HIGH CONFIDENCE. VFR.
SUNDAY...MODERATE CONFIDENCE. MAINLY VFR. SCATTERED MVFR IN
SHOWERS AS A COLD FRONT PASSES THROUGH.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH WEDNESDAY NIGHT/...HIGH CONFIDENCE.
TONIGHT...
EAST WINDS NEAR 20 KNOTS WILL DIMINISH. BUT ROUGH SEAS WILL KEEP
SMALL CRAFT ADVISORY GOING ON MOST WATERS. WEAK LOW PRESSURE
MOVING UP THE COAST WILL PASS JUST OFFSHORE...BRINGING DIMINISHING
LIGHT RAIN ALONG WITH CLOUDS/FOG/DRIZZLE.
WEDNESDAY AND WEDNESDAY NIGHT...STRONG SOUTH WINDS WILL MOVE UP
THE COAST FROM THE CAROLINAS WEDNESDAY...REACHING THE NEW ENGLAND
WATERS IN THE AFTERNOON AND LINGERING THROUGH THE NIGHT. WINDS
WILL REACH 50-65 KNOTS ABOUT 2000 FEET ABOVE THE OCEAN SURFACE.
BUT A STRONG TEMPERATURE INVERSION MAY KEEP ALL OF THIS WIND FROM
REACHING THE SURFACE. EVEN SO...HEAVY DOWNPOURS MAY PROVIDE A
CHANNEL FOR SOME OF THIS WIND TO REACH THE SURFACE IN GUSTS. WE
ARE CURRENTLY FORECASTING GUSTS TO 30 KNOTS OR THE LOWER 30S. LOW
CONFIDENCE FOR GUSTS REACHING GALE FORCE. EXPECT FOG AND RAIN
WITH LOCAL HEAVY DOWNPOURS.
OUTLOOK...THURSDAY THROUGH SUNDAY...MODERATE CONFIDENCE
CHRISTMAS...WINDS SHIFT TO SW/W WITH GALE FORCE GUSTS POSSIBLE.
IMPROVING VSBYS IN THE AFTERNOON AS RAIN MOVES OUT.
FRI AND SAT...EXPECT WEST WINDS BELOW SMALL CRAFT ADVISORY LEVELS
FRI. INCREASING SOUTHWEST WINDS SAT WITH GUSTS TO 25 KT.
SUNDAY...WEST TO NORTHWEST WINDS MAY GUST TO 25 KT ACROSS THE
OUTER COASTAL WATERS. MAY ALSO SEE 5 FOOT SEAS ACROSS THE OUTER
COASTAL WATERS AS WELL.
&&
.TIDES/COASTAL FLOODING...
EASTERN MASSACHUSETTS COAST:
HIGH TIDE AT BOSTON WILL BE 11.7 FT AT MIDDAY WEDNESDAY WITH A
SURGE OF AROUND 1.0 FT. THE SURGE TODAY /TUESDAY/ SHOWED MINOR
SPLASHOVER ALONG THE EAST MASSACHUSETTS COAST. EXPECT SIMILAR
EFFECTS WEDNESDAY. A COASTAL FLOOD ADVISORY HAS BEEN ISSUED FOR
THE EAST MASSACHUSETTS COAST FOR THE MIDDAY WEDNESDAY HIGH TIDE.
SOUTH COAST:
WE DO NOT EXPECT MUCH IF ANY COASTAL FLOODING ALONG THE SOUTH COAST.
NOT ENOUGH WIND OR SURGE FOR THE WEDNESDAY EVENING HIGH TIDE.
HIGHEST SURGE OF 1-2 FEET LIKELY TO OCCUR DURING LOW TIDE LATE WED
NIGHT WITH THE SURGE AND SEAS DECREASING DURING THE CHRISTMAS
MORNING HIGH TIDE. WORST CASE IS MINOR SPLASHOVER FOR THE
CHRISTMAS MORNING HIGH TIDE BUT EVEN THIS IS NOT LOOKING
FAVORABLE.
&&
.CLIMATE...
RECORD HIGHS FOR DEC 24 / DEC 25...
BOS...61 IN 1996 / 65 IN 1889 PVD...60 IN 1990 / 63 IN 1964
BDL...59 IN 1996 / 64 IN 1964 ORH...57 IN 1996 / 60 IN 1964
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING
FOR CTZ002>004.
MA...FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING
FOR MAZ002>022-026.
COASTAL FLOOD ADVISORY FROM 9 AM TO 4 PM EST WEDNESDAY FOR
MAZ007-014>016-019-022.
RI...FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING
FOR RIZ001>007.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM WEDNESDAY TO 6 AM EST THURSDAY
FOR ANZ231>234-236.
SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ235-237-
250-251-254>256.
&&
$$
SYNOPSIS...WTB/BELK
NEAR TERM...WTB/BELK
SHORT TERM...WTB
LONG TERM...BELK
AVIATION...WTB/BELK
MARINE...WTB/BELK
TIDES/COASTAL FLOODING...WTB
CLIMATE...STAFF
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
937 PM EST TUE DEC 23 2014
.DISCUSSION...
...POTENTIAL FOR STRONG STORMS TOMORROW...
WARM AND CONDITIONS ACROSS THE REGION THIS EVENING WITH TEMPERATURES
STILL IN THE LOW 70S AND DEWPOINTS IN THE UPPER 60S. RADAR REMAINS
QUIET FOR EAST CENTRAL FLORIDA WITH RUC ANALYSIS SHOWING A FAIRLY
SIGNIFICANT POCKET OF MID LEVEL DRY AIR IN PLACE ACROSS THE
PENINSULA. THIS POCKET WILL CONTINUE TO BE ERODED WITH TIME AS THE
FAIRLY DEEP MOISTURE ASSOCIATED WITH THE ONGOING WEATHER OVER THE
GULF STATES AND PANHANDLE PUSHES EAST.
CURRENT TRENDS WITH THE FIRST OF TWO PRE-FRONTAL BANDS NOW OVER THE
EASTERN PANHANDLE/BIG BEND AREA BACK INTO THE EASTERN GULF SHOW MOST
OF THE STORMS LIFTING FURTHER NORTHEAST OVERNIGHT. HAVE KEPT IN THE
MENTION OF A FEW SHOWERS AND POSSIBLE A STORM NORTHWEST OF I-4
STARTING LATE TONIGHT FOR ANY ACTIVITY THAT MAKES IT INTO THE NATURE
COAST AND ACROSS THE PENINSULA.
OTHERWISE EXPECT REMAINDER OF THE OVERNIGHT HOURS TO BE FAIRLY QUIET
ACROSS THE REGION WITH LOCAL FOG AND STRATUS BEING THE MAIN
CONCERNS. BOUNDARY LAYER WINDS HAVE PICKED UP TO AROUND 30KTS JUST
OFF THE SURFACE WHICH SHOULD HELP LIMIT ANY VISIBILITY CONCERNS AND
MAINLY SEE JUST STRATUS DEVELOPMENT.
LOWS WILL BE MORE MILD IN THE UPPER 60S TO LOW 70S ALONG COASTAL
AREAS SOUTH OF THE CAPE.
MODIFIED PREVIOUS DISCUSSION...WEDNESDAY...LOW PRESSURE OVER THE
OHIO VALLEY WILL CONTINUE TO DEEPEN AS IT LIFTS NORTHWARD INTO THE
GREAT LAKES REGION TOMORROW. THE COLD FRONT ASSOCIATED WITH THIS
SYSTEM WILL MOVE THROUGH THE SOUTHEAST U.S. AND INTO THE EASTERN
GULF THROUGH THE DAY. THE MAIN ONGOING SQUALL LINE/PREFRONTAL BAND
OUT AHEAD OF IT WILL LIKELY LOSE SOME INTENSITY AS IT SHIFTS FARTHER
AWAY FROM AMPLIFIED TROUGH AND 250MB JET INTO PENINSULAR FLORIDA
INTO THE AFTERNOON AND EVENING. HOWEVER THE CONCERN REMAINS FOR A
STORMS TO PRODUCE STRONG TO SEVERE WIND GUSTS AS LOW/MID LEVEL S/SW
WINDS WILL BE IN THE 35-40KT RANGE. AS OFTEN HAPPENS...ONGOING
SHOWERS AND STORMS OVER THE EASTERN GULF EARLY IN THE DAY WILL
LIKELY KEEP MID-HIGH CLOUDS IN PLACE AND LIMIT INSTABILITY SOMEWHAT
OVER WHAT WOULD OTHERWISE BE EXPECTED.
GENERAL TREND WILL BE FOR RAIN CHANCES TO INCREASE STEADILY FROM THE
LATE MORNING ONWARDS AS THE PREFRONTAL BAND MOVES ONSHORE THE WEST
COAST OF FL AND ACROSS THE REGION. IF WE SEE MORE SUNSHINE...WARM
AND MOIST CONDITIONS MAY ALLOW FOR A FEW SHOWERS TO POP UP AHEAD OF
THE MAIN LINE. RAIN CHANCES WILL RANGE FROM 40-50 PERCENT ALONG THE
TREASURE COAST TO 70-80 PERCENT NORTHWEST TO LAKE AND VOLUSIA
COUNTIES. TEMPS WILL REMAIN ABOVE NORMAL WITH HIGHS IN THE LOW TO
MID 80S. MELBOURNE AND VERO BEACH MAY COME CLOSE TO RECORDS FOR THE
DAY.
&&
.AVIATION...
PREVAILING VFR CONDITIONS THROUGH 24/05Z. IFR/LIFR CIGS DEVELOPING
IN STRATUS 05Z-13Z WITH INCREASING BOUNDARY LAYER WINDS LIMITING
FOG/LOW VSBY POTENTIAL. LOW LEVEL WIND SHEAR REMAINS IN TAFS AS
SOUTHERLY WINDS INCREASE TO 30-35KTS AROUND 1500-2000FT AFTER
24/03Z. FOG/STRATUS BREAKS APART AFTER 14Z WITH ANY CIGS GENERALLY
BECOMING VFR. PREFRONTAL BAND OF SHOWERS AND STORMS EXPECTED TO MOVE
INTO REGION FROM NW AFTER 24/16Z...WITH A FEW STRONGER STORMS
POSSIBLE. WARM AND MOIST ATMOSPHERE MAY LEAD TO ISOLD ACTIVITY
OUTSIDE OF MAIN LINE. GUSTY S-SW WINDS OUTSIDE OF ANY CONVECTION
WITH PREVAILING 12-15KTSG25KTS.
&&
.MARINE...
BUOY 41009 HAS BEEN CONSISTENT OVER THE PAST FEW HOURS WITH
SUSTAINED SOUTH-SOUTHEAST WINDS AROUND 20KTS WITH GUSTS TO 25KTS.
GIVEN THAT THE TREND WILL CONTINUE TO BE UPWARDS AS THE GRADIENT
TIGHTENS AHEAD OF THE FRONT MOVING OVER THE FL PANHANDLE THIS
EVENING...WILL GO AHEAD AND START THE ADVISORY FOR THE OFFSHORE
WATERS WITH THE 10PM UPDATE. SMALL CRAFT SHOULD EXERCISE CAUTION
NEAR THE COAST. SOUTH-SOUTHEAST WINDS OVERNIGHT 20KTS
OFFSHORE...15-20KTS NEARSHORE VEERING SOUTHWEST BY LATE TOMORROW
AFTERNOON AS THE FRONT MOVES CLOSER. SEAS BUILDING TO 5-6FT WELL
OFFSHORE LATE TONIGHT AND 3-5FT NEARSHORE AND CONTINUING INTO
WEDNESDAY.
&&
.CLIMATE...
WARM AND BREEZY SOUTHERLY FLOW WILL CONTINUE TO BRING WARM
TEMPERATURES ACROSS THE STATE AHEAD OF A FRONT ON WEDNESDAY.
RECORD HIGH 24 DEC
DAYTONA BEACH............84 (1981)
ORLANDO..................84 (1970)
MELBOURNE................85 (1978)
VERO BEACH...............84 (2002)
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 PM EST WEDNESDAY
FOR WATERS FROM FLAGLER BEACH TO JUPITER INLET 20 TO 60 NM.
&&
$$
MOSES/PENDERGRAST
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1015 AM EST MON DEC 22 2014
.DISCUSSION...
DEEP S/SW FLOW ACRS THE FL PENINSULA/ERN GOMEX THIS MORNING DUE TO
THE AN H100-H70 RIDGE AXIS OVER THE FL STRAITS. THESE WINDS HAVE
SHUNTED THE FRONTAL BOUNDARY THAT WAS STALLED OVER THE NRN PENINSULA
BACK INTO THE PANHANDLE...ALLOWING A SLIGHTLY DRIER AND MORE STABLE
AIRMASS TO PUSH INTO CENTRAL FL. MORNING SOUNDINGS FROM KTBW/KMFL
SHOW THE DRIER AIR BLO H80 WITH AVG DEWPOINT DEPRESSIONS BTWN 8-12C
AND AS HIGH AS 20C. RUC ANALYSIS PICKING UP ON THIS DRY AIR...
INDICATING MEAN RH VALUES THRU THE H100-H70 LYR BLO 70PCT...AS LOW
AS 55PCT IN THE H100-H85 LYR OVER THE TREASURE COAST.
ALOFT...A 100-120KT H30-H20 JET STREAK LIFTING ACRS THE DEEP
SOUTH/MID ATLC REGION HAS PULLED ALMOST ALL OF THE LCL DYNAMIC
FORCING NORTH OF CENTRAL FL. VORTICITY IS ALMOST NONEXISTENT THRU
THE H85-H30 LYR. A THIN BAND OF UPR LVL DIVERGENCE OVER THE ERN
GOMEX HAS INDUCED A LCL AREA OF CONVECTION...BUT THE MEAN FLOW WILL
CARRY ANY PRECIP ALONG AND N OF THE I-4 CORRIDOR. INDEED...BOTH
HRRR/LCL WRF MODELS GENERATE LITTLE IF ANY PRECIP OVER THE CWA...AND
ALL OF IT IN THE VCNTY OF I-4.
DESPITE BETTER INSOLATION OVER THE S...THE COMBINATION OF LOW LVL
DRY AIR AND WEAK DYNAMIC FORCING WILL PREVENT THE FORMATION OF ANY
ORGANIZED PRECIP OVER THE SRN CWA...AND ANY DEEP CONVECTION OVER THE
N. WILL SHAVE POPS BACK TO CHC/SLGT CHC FROM BREVARD/OSCEOLA COUNTY
NWD...REMOVING TSRAS IN THE PROCESS. FROM INDIAN RIVER/OKEECHOBEE
SWD...BLO MENTIONABLE POPS.
&&
.AVIATION...THRU 23/12Z
SFC WNDS:
THRU 23/00Z...S/SW 8-12KTS. AFT 23/12Z...S/SW 3-6KTS.
VSBYS/WX:
THRU 23/06Z...SLGT CHC MVFR SHRAS N OF KVRB-KLAL...INCRSG TO CHC N
OF KTIX-KISM. AFT 23/06Z...AREAS MVFR BR ALL SITES...LCL LIFR FG
VCNTY KVRB/KFPR/KLEE.
CIGS/WX:
THRU 23/00Z...BTWN FL080-100 WITH PDS MVFR BTWN FL020-030 IN PASSING
SHRAS. BTWN 23/00Z-23/06Z...BCMG MVFR BTWN FL015-025 IN -RA. AFT
23/06Z...WDSPRD IFR BTWN FL006-009 WITH AREAS LIFR BLO FL004.
&&
.MARINE...
WEAK SFC RIDGE OVER THE FL STRAITS WILL COMBINE WITH AN OPEN FRONTAL
TROF OVER N FL TO MAINTAIN A LIGHT TO GENTLE SRLY BREEZE ACRS THE
LCL ATLC THIS AFTN. DESPITE THE WEAK SFC/BNDRY LYR FLOW...DATA BUOYS
HAVE MEASURED A SMALL BUT DISCERNIBLE INCREASE IN SEAS OVER THE PAST
24HRS DUE TO THE ARRIVAL OF A 2-3FT ERLY SWELL. WARM FRONT HAS
LIFTED WELL N OF FLAGLER BEACH AND SHOWING NO SIGNS OF REVERSING
COURSE...IN ITS WAKE A LCL POCKET OF DRY AIR WILL MOVE UP FROM THE S
PENINSULA AND QUASH RAIN CHANCES S OF THE CAPE.
LITTLE CHANGE IN THE WX PATTERN AS THE HI PRES RIDGE TO THE SOUTH
HOLDS THE LINE. SEAS 2-3FT NEARSHORE AND 3-4FT OFFSHORE.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...CRISTALDI
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
344 AM EST MON DEC 22 2014
.DISCUSSION...
...WARM/HUMID AIR MASS THROUGH WED...
...GOOD CHANCE FOR SHOWERS/STORMS WED AND WED NIGHT THEN COOLING
AND GRADUAL DRYING EXPECTED CHRISTMAS DAY...
CURRENTLY-TODAY...INCREASED SOUTHERLY WINDS PROVIDING LOW LEVEL
WARM ADVECTION...A WEAK SURFACE BOUNDARY AND SOME JET DIVERGENCE
COMBINED TO GENERATE A BAND OF CONVECTION THAT PRIMARILY AFFECTED
OUR NORTHERN AREAS. THE BOUNDARY WILL LIFT NORTH OF THE AREA BY
THIS AFTERNOON WHILE MAIN JET DIVERGENCE LIFTS WELL TO THE
NORTHEAST. THIS WILL CAUSE CONVECTIVE BAND TO MOVE AWAY FROM THE
AREA EARLY THIS MORNING.
FORECAST SOUNDINGS DO NOT LOOK VERY SUPPORTIVE FOR ADDITIONAL
AFTERNOON CONVECTION AS A WEAK SUBSIDENCE INVERSION IS INDICATED
BEHIND THE IMPULSE ALOFT. THE HRRR AND LOCAL WRF GENERATE LITTLE
TO NO CONVECTION OVER THE CENTRAL/SOUTH THIS AFTERNOON.
STILL...WITH A VERY MOIST AIR MASS...POSSIBLY A LITTLE SOLAR
INSOLATION AND SOME WEAK IMPULSES IN FAST SOUTHWEST FLOW
ALOFT...EXPECT A CHANCE OF SHOWERS AND A SLIGHT CHANCE OF
STORMS...MAINLY ACROSS NORTH AND CENTRAL SECTIONS WHERE THE
MOISTURE WILL BE HIGHEST.
TONIGHT...ANY CONVECTION THAT IS GENERATED THIS AFTERNOON WILL END
BEFORE MIDNIGHT. LOW LEVEL MOISTURE WILL BE HIGH AND MOS IS
SHOWING LOW CLOUDS AND FOG. BOUNDARY LAYER WINDS ARE FORECAST TO
BE 10 KNOTS SO WILL NOT PLAN ON WIDESPREAD DENSE FOG.
TUE-THU...GFS AND ECMWF SHOWING THE SAME PATTERN AS THEY LIFT THE
DEEPENING UPPER LEVEL LOW OVER IOWA NORTHEAST AND DEVELOP ANOTHER
LOW IN THE BASE OF THE TROUGH AS IT MOVES OKLAHOMA/TEXAS OVERNIGHT
TUESDAY INTO WEDNESDAY. BOTH MODELS SHOWING A 6 TO 12 HOUR SLOW
DOWN FROM PREVIOUS MODELS CYCLES PUTTING THE FRONT CLEARING
CENTRAL FLORIDA DURING THE DAY CHRISTMAS DAY. COOLER AIR ALOFT...-10C
TO -12C AT 500 MB...AND DISTURBANCES MOVING QUICKLY SOUTHWEST TO
NORTHEAST IN THE SOUTHWEST FLOW AHEAD OF THE TROUGH SHOULD TRIGGER
ISOLATED STORMS DURING THE TUESDAY. BOTH GFS AND ECMWF SHOW A COLD
FRONT SWEEPING ACROSS THE CENTRAL GULF OF MEXICO WEDNESDAY.
TEMPERATURES ALOFT WILL BE MARGINALLY COOL...-8C TO -10C AND MID LEVEL
DISTURBANCES WILL CONTINUE TO MOVE AROUND THE BASE OF THE UPPER
LEVEL TROUGH. THE FRONT SHOULD DROP QUICKLY ACROSS EAST CENTRAL
FLORIDA AND CLEAR THE FORECAST AREA CHRISTMAS DAY LEAVING ONLY
LINGERING SHOWERS IN SOUTHERN AREAS.
FRI-SUN...COOLER AND DRIER AIRMASS WILL BUILD IN BEHIND THE FRONT
FRIDAY THE SHIFT INTO THE ATLANTIC SATURDAY AND SUNDAY AS ANOTHER
TROUGH BEGINS DIGGING SOUTHWARD OVER THE NATIONS MIDSECTION. MID
LEVEL DISTURBANCES IN THE MOISTENING SOUTHWEST TO NORTHEAST FLOW IN
THE SOUTHWEST FLOW AHEAD OF THE TROUGH RESULTS IN VARIABLE CLOUDY
SKIES AND MINIMAL RAIN CHANCES.
&&
.AVIATION...
AREA OF SHOWERS WILL LIFT NORTH OF KLEE AND KDAB BY 12Z. NEAR
SATURATION OF THE LOW LEVELS WILL PRODUCE AREAS OF LOW CEILINGS
AND FOG THROUGH 13-14Z WITH MAINLY MVFR-IFR CONDITIONS. THIS WILL
BE MOST LIKELY FROM ABOUT KISM-KMCO-KTIX NORTHWARD. CEILINGS WILL
IMPROVE TO MVFR BY AROUND 15Z AND THEN VFR THIS AFTERNOON. THERE
IS A CHANCE FOR ADDITIONAL SHOWERS/STORMS TO FORM IN THE AFTERNOON
AND EARLY EVENING. ANOTHER ROUND OF LOW STRATUS IS EXPECTED
TONIGHT...STARTING IN THE LATE EVENING TO AROUND MIDNIGHT IN THE
NORTH AND IN THE PRE-DAWN HOURS ALONG THE SPACE/TREASURE COAST.
&&
.MARINE...
TODAY-TONIGHT...BOUNDARY WITH ITS ASSOCIATED SHOWERS AND RAIN
COOLED AIR ACROSS THE NORTHERN WATERS WILL LIFT NORTH AND PLACE
THE ENTIRE AREA IN A SOUTHERLY WIND FLOW BY AFTERNOON. SPEEDS LOOK
TO BE 10-15 KNOTS. DIURNAL INCREASE TO ABOUT 15 KNOTS SHOULD OCCUR
TONIGHT ESPECIALLY OVER THE GULF STREAM. EXPECT SCATTERED MORNING
SHOWERS AND ISOLATED STORMS NEAR/ALONG THE GULF STREAM AND A
SLIGHT CHANCE FOR STORMS TO MOVE OFF THE COAST THIS AFTERNOON AND
EVENING FROM THE CAPE NORTH.
TUE-FRI...COLD FRONT MOVING INTO THE EASTERN U.S. WILL CROSS FLORIDA
INTO LATE WED AND WED NIGHT. SOUTHERLY WINDS WILL INCREASE UP TO 20
KNOTS AHEAD OF THIS FRONT AND THEN SWITCH TO THE W/NW AS THE
BOUNDARY PASSES...REMAINING ELEVATED INTO CHRISTMAS MORNING. THESE
WINDS WILL BUILD SEAS UP TO 6 FEET OFFSHORE WEDNESDAY AND POSSIBLY
UP TO 7 FEET IN THE GULF STREAM AS THEY BECOME MORE NORTHWESTERLY
CHRISTMAS DAY. MAY NEED SMALL CRAFT ADVISORY OVERNIGHT TUESDAY AND
WEDNESDAY AS THE SOUTHERLY FLOW AHEAD OF THE UPPER LEVEL TROUGH
TIGHTENS AND WINDS INCREASE TO 20 KNOTS OR MORE. WINDS BEGIN TO
DIMINISH LATE CHRISTMAS DAY AND CONTINUE TO DIMINISH ON CHRISTMAS
NIGHT AND FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 76 65 80 69 / 60 30 40 40
MCO 79 64 82 67 / 30 20 30 40
MLB 80 66 82 72 / 30 20 20 30
VRB 81 66 81 71 / 20 10 20 20
LEE 77 64 81 66 / 50 30 40 50
SFB 78 65 82 67 / 50 30 40 40
ORL 77 65 81 68 / 40 20 30 40
FPR 81 66 81 71 / 20 10 10 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM...LASCODY
LONG TERM....WIMMER
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
748 PM EST TUE DEC 23 2014
.UPDATE...
LINE OF STRONG TO SEVERE THUNDERSTORMS ACROSS CENTRAL AL CONTINUES
EASTWARD THIS EVENING. THE LINE IS HOLDING STEADY AND IS EXPECTED
TO REACH THE AL/GA STATE LINE AROUND 10 PM. THE HRRR BEGINS TO
WEAKEN THE LINE RIGHT ALONG THE INTERSTATE 85 CORRIDOR RIGHT
AROUND OR JUST AFTER MIDNIGHT. GRADUAL WEAKENING OF THE LINE WOULD
OCCUR IF THE WEDGE CONTINUED TO HOLD STRONG EAST OF 85.
HOWEVER...STORMS SHOULD BECOME ELEVATED ACROSS THE EASTERN
PORTIONS OF THE CWFA. DO THINK SOME CONTINUED EROSION ON THE WEST
SIDE OF THE WEDGE IS LIKELY...BUT NOT CONFIDENCE ON EXACTLY HOW
MUCH.
HAVE MADE SOME TIMING TWEAKS FOR TSRA WITHIN THE GRIDS. IN
ADDITION...TWEAKED THE HOURLY TEMP/DEW GRIDS ACCORDING TO THE
POSITION OF THE WARM FRONT.
&&
.PREV DISCUSSION... /ISSUED 622 PM EST TUE DEC 23 2014/
PREV DISCUSSION... /ISSUED 244 PM EST TUE DEC 23 2014/
.SEVERE STORMS REMAIN POSSIBLE TONIGHT AND WEDNESDAY...
.HEAVY RAINFALL AND MINOR FLOODING LIKELY TONIGHT AND
WEDNESDAY...
SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
OVERALL FCST IN GOOD SHAPE. WARM FRONT STILL VERY SLOW TO MOVE
NORTH BUT SHOULD MARCH SLOWLY NORTH TONIGHT.
MONITORING SEVERE STORM IN NW GA THAT HAS HISTORY OF PRODUCING
DAMAGING WINDS. STORM MAY HAVE TRAVELED ALONG WRN PERIPHERY OF
WEDGE. WILL BE A FEW HOURS BEFORE NORTH GA SEES ANOTHER ROUND OF
POSSIBLE SVR STORMS. AS MENTIONED IN PREV DISCUSSION /SEE UPDATE
SECTION BELOW/ INGREDIENTS REMAIN IN PLACE FOR SVR STORMS TONIGHT
AND WED MORNING...GREATEST THREAT 03Z-15Z OR SO.
AS FRONT SWEEPS THRU WED AFTERNOON...SHOULD SEE RAPID END TO PRECIP
AND ERODING OF LOW CLOUDS. NOT MUCH CHC FOR WINTER PRECIP WED NIGHT
EVEN IN HIGHER ELEVATIONS. SOME IN ELEV ABOVE 2500FT MAY SEE A BRIEF
MIX OF LIGHT RAIN WITH SNOW FLURRIES BUT NO IMPACTS EXPECTED.
SNELSON
UPDATE...
/ISSUED AT 129 PM EST TUE DEC 23 2014/
FCST GRIDS UPDATED EARLIER THIS MORNING TO ACCOUNT FOR OBSERVED
TRENDS. 12Z MODELS...PARTICULARLY GFS...TOO QUICK LIFTING WARM
FRONT WHICH IS CURRENTLY LOCATED FROM AROUND COLUMBUS TO VIDALIA.
TEMPS WILL LIKELY REMAIN IN THE 40S IN NORTH GA AND 50S TO 60S
OVER MIDDLE GA.
COVERAGE OF RAINFALL OVER AL A LITTLE LESS THAN WHAT 12Z HIRES
MODELS INDICATING...POSSIBLY DUE TO LARGE EXPANDING AREA OF
CONVECTION OVER SRN AL AND SW GA. NEW 18Z CYCLE WPC QPF GUIDANCE
INDICATING ABOUT 1-2 INCHES OVER AREAS NORTH OF COLUMBUS TO MACON.
WILL REVIEW THIS BEFORE RELEASING FINAL FORECAST. BASED ON PREV
FCST AND ALREADY SOME REPORTS OF NUISANCE/MINOR FLOODING HAVE
ISSUED FLOOD WATCH FOR ALL OF CWA.
THREAT FOR SEVERE WX STILL IN PLACE THOUGH CONCERNED ABOUT
POSSIBLE UPSTREAM CONVECTION MENTIONED EARLIER DISRUPTING VERTICAL
WIND SHEAR AND INSTABILITY. THAT SAID...STILL SEEING FAIRLY STRONG
ISOLATED CELLS IN NRN/WRN AL ATTM WHERE MLCAPE VALUES TRYING TO
CREEP UP TO 250-500 J/KG. 0-1KM BULK SHEAR ONLY 20-30KTS IN AL.
12Z MODEL VALUES FOR TONIGHT SILL FAVORABLE FOR HIGH SHEAR LOW
CAPE CONVECTION AND QLCS MODES. NAM STILL HIGHER THAN GFS FOR
SHEAR AND MLCAPE...AVERAGING AROUND 100-300 J/KG MLCAPE AND 35-45
FOR 0-1KM BULK SHEAR. SHEAR DROPS SOME DURING DAY ON WED SO
TORNADO THREAT MAY LOWER ACCORDINGLY.
CONTINUING TO MONITOR.
SNELSON
LONG TERM /THURSDAY THROUGH TUESDAY/...
BEHIND A COLD FRONT THAT PUSHES EAST OF THE AREA EARLY THURSDAY
MORNING... WRAP AROUND CLOUDS AND MOISTURE MAY BE A BIT SLOW TO
CLEAR FROM WEST TO EAST THURSDAY MORNING DUE TO A LAGGING STRONG
UPPER DISTURBANCE THAT DOES NOT PUSH EAST OF THE STATE UNTIL EARLY
THURSDAY AFTERNOON. OTHERWISE... EXPECT DRY HIGH PRESSURE TO BUILD
OVER THE AREA THURSDAY AFTERNOON WITH CLEARING CONDITIONS AND HIGH
TEMPERATURES MOSTLY IN THE 50S. THE COOLEST TEMPERATURES WILL BE
FELT FRIDAY MORNING WITH LOWS MOSTLY IN THE 30S. THEN MODELS AGREE
ON THE SURFACE RIDGE SHIFTING EAST ON FRIDAY...AND ESTABLISHING A
WARMING...MOIST SOUTHERLY FLOW GOING INTO THE WEEKEND. THIS AHEAD OF
ANOTHER LOW PRESSURE SYSTEM THAT SHOULD BRING RAIN CHANCES TO THE
AREA OVER THE WEEKEND. LONG RANGE MODELS STILL SHOW SOME TIMING
DIFFERENCES... WITH THE FASTER GFS SPREADING SHOWERS INTO THE AREA
ON SATURDAY...AND HOLDING RAIN CHANCES ACROSS THE AREA INTO MONDAY
WHEN A SLOW MOVING COLD FRONT FINALLY TRAVERSES THE AREA. THE SLOWER
ECMWF HOLD RAIN CHANCES OFF UNTIL MAINLY SUNDAY...BUT THEN DOES SHOW
A COLD FRONT PUSHING ACROSS THE AREA MONDAY NIGHT-EARLY TUESDAY...
WITH BOTH SHOWING HIGH PRESSURE AND DRIER CONDITIONS IN CONTROL BY
TUESDAY. AT THIS TIME... LACK OF INSTABILITY AND STRONG UPPER
FORCING WARRANTS ONLY SHOWERS SO FAR WITH THIS SYSTEM... HOWEVER
THIS COULD CHANGE SO STAY TUNED.
39
HYDROLOGY...
DECIDED TO PLAY IT SAFE AND POST A FLOOD WATCH FOR MOST OF NORTH
AND CENTRAL GA THROUGH 8 PM WEDNESDAY DUE TO THE EXPECTED 2 TO 3
INCHES OF ADDITIONAL RAINFALL THROUGH WEDNESDAY AFTERNOON AHEAD OF
A COLD FRONT. ISOLATED HIGHER AMOUNTS ARE ALMOST CERTAIN... AND
WITH NEARLY 100 PERCENT RUNOFF OF ANY RAINFALL INTO CREEKS...
STREAMS AND RIVERS THIS TIME OF YEAR... RAPID RISES ARE
EXPECTED...THAT COULD RESULT IN FLOODING. IN ADDITION TO RIVER
FLOODING... ISOLATED FLASH FLOODING IS ALSO POSSIBLE DUE TO FALL
VEGETATION AND OTHER DEBRIS CLOGGING DRAINAGE SYSTEMS OR NARROWS
ALONG CREEKS AND STREAMS. ALL INTEREST ACROSS NORTH AND CENTRAL GA
SHOULD MONITOR CONDITIONS CLOSELY AND BE ALERT FOR POSSIBLE FLOOD
WARNINGS. THOSE LIVING IN AREAS PRONE TO FLOODING SHOULD BE
PREPARED TO TAKE ACTION SHOULD FLOODING DEVELOP. THE RAINFALL
SHOULD END FROM WEST TO EAST WEDNESDAY AFTERNOON AND GREATLY
LESSON THE THREAT OF FLOODING BY WEDNESDAY EVENING.
AVIATION...
00Z UPDATE...
WARM FRONT WILL CONTINUE TO MOVE NORTH ACROSS CENTRAL GA THIS
EVENING. A LINE OF THUNDERSTORMS AHEAD OF A COLD FRONT SHOULD
IMPACT ATL BETWEEN 04Z AND 07Z ACCORDING TO THE LATEST TIMING OF
THE HRRR. THE CIG FORECAST MAY BE TRICKY...IF THE WARM FRONT MOVES
NORTH OF ATL...CIGS COULD BRIEFLY IMPROVE. HOWEVER...BELIEVE WITH
THE STRONG WEDGE IN PLACE...GOING TO LEAVE THEM AT LIFR. SLOW
IMPROVEMENT TOMORROW TO MVFR. WINDS SHOULD BEGIN TO SHIFT TO THE
SW BY THE AFTERNOON.
//ATL CONFIDENCE...00Z UPDATE...
HIGH CONFIDENCE ON TIMING OF LINE OF THUNDER. LOW-MED CONFIDENCE
ON CIGS.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 46 45 66 40 / 100 100 100 30
ATLANTA 50 48 65 39 / 100 100 100 10
BLAIRSVILLE 55 43 58 35 / 100 100 100 30
CARTERSVILLE 50 49 64 37 / 100 100 90 10
COLUMBUS 64 62 66 40 / 100 100 90 10
GAINESVILLE 44 42 61 39 / 100 100 100 30
MACON 56 55 68 41 / 100 100 100 20
ROME 52 50 62 37 / 100 100 90 10
PEACHTREE CITY 54 53 66 37 / 100 100 100 10
VIDALIA 58 56 71 47 / 100 100 100 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH WEDNESDAY EVENING FOR THE FOLLOWING ZONES:
BALDWIN...BANKS...BARROW...BARTOW...BIBB...BLECKLEY...BUTTS...
CARROLL...CATOOSA...CHATTAHOOCHEE...CHATTOOGA...CHEROKEE...
CLARKE...CLAYTON...COBB...COWETA...CRAWFORD...CRISP...DADE...
DAWSON...DE KALB...DODGE...DOOLY...DOUGLAS...EMANUEL...FANNIN...
FAYETTE...FLOYD...FORSYTH...GILMER...GLASCOCK...GORDON...
GREENE...GWINNETT...HALL...HANCOCK...HARALSON...HARRIS...HEARD...
HENRY...HOUSTON...JACKSON...JASPER...JEFFERSON...JOHNSON...
JONES...LAMAR...LAURENS...LUMPKIN...MACON...MADISON...MARION...
MERIWETHER...MONROE...MONTGOMERY...MORGAN...MURRAY...MUSCOGEE...
NEWTON...NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PEACH...
PICKENS...PIKE...POLK...PULASKI...PUTNAM...ROCKDALE...SCHLEY...
SOUTH FULTON...SPALDING...STEWART...SUMTER...TALBOT...
TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...TOWNS...TREUTLEN...
TROUP...TWIGGS...UNION...UPSON...WALKER...WALTON...WARREN...
WASHINGTON...WEBSTER...WHEELER...WHITE...WHITFIELD...WILCOX...
WILKES...WILKINSON.
TORNADO WATCH UNTIL MIDNIGHT EST TONIGHT FOR THE FOLLOWING
ZONES: CHATTAHOOCHEE...HARRIS...HEARD...MARION...MUSCOGEE...
SCHLEY...STEWART...SUMTER...TROUP...WEBSTER.
&&
$$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
114 PM EST MON DEC 22 2014
.SYNOPSIS...
UNSETTLED WEATHER IS EXPECTED THROUGH TUESDAY NIGHT AS SEVERAL
DISTURBANCES MOVE OVER THE REGION. A STRONG COLD FRONT WILL THEN
MOVE THROUGH THE AREA WEDNESDAY EVENING. DRY HIGH PRESSURE WILL
SETTLE OVER THE SOUTHEAST INTO THE WEEKEND. ANOTHER COLD FRONT
COULD SHIFT THROUGH THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A MUCKY PATTERN WILL CONTINUE FOR YET ANOTHER DAY AS A STRONG
WEDGE OF HIGH PRESSURE REMAINS OVER THE MID-ATLANTIC REGION AND
EXTENDS DOWN THE EASTERN SEABOARD AS FAR SOUTH AS SOUTHERN GA. A
DEEP UPPER LEVEL TROUGH OVER THE CENTRAL UNITED STATES CONTINUES
TO PROVIDE A STEADY FEED OF SHORTWAVE ENERGY ACROSS THE SOUTHEAST
STATES. INITIALLY IT SEEMED AS THOUGH THE JET DIVERGENCE WAS GOING
TO WEAKEN TODAY AND THE STRONGEST SHORTWAVE ENERGY WOULD SHIFT
NORTHEAST OF THE REGION. HOWEVER WE HAVE NOTED A FAIRLY WIDESPREAD
AREA OF RAIN MOVING OUT OF CENTRAL GA INTO OUR FORECAST AREA THIS
MORNING. THIS IS ASSOCIATED WITH A WEAK SLUG OF ISENTROPIC OMEGA
THAT THE 12Z NAM FINALLY PICKED UP ON. THE LATEST HRRR HAS ALSO
CAUGHT ONTO THE INLAND PRECIP WHICH SHOULD PROGRESS NORTHEAST
THROUGH THE AREA THIS AFTERNOON. SIGNIFICANT CHANGES TO THE POP
GRIDS WERE IN ORDER THIS MORNING. WE ARE NOW CARRYING LIKELY OR
CATEGORICAL POPS OVER MANY LAND AREAS THROUGH EARLY AFTERNOON...
GRADUALLY TAPERING BACK LATE THIS AFTERNOON ONCE THE BEST FORCING
MOVES AWAY TO THE NORTHEAST. DENSE OVERCAST AND STEADY RAIN WILL
KEEP TEMPERATURES FAIRLY STEADY IN THE UPPER 40S TO LOWER 50S.
SOUNDINGS SHOW LOW-MID 50S AIR AT THE SURFACE TODAY AND THIS
EVENING AND MID 60S AIR AT 300-400 FT WHICH IS PRIME FOR STRATUS
BUILDING DOWN GIVEN A SETUP WITH LIGHTER WINDS IN THE BOUNDARY
LAYER. THE STORY TONIGHT SHOULD BE FOG...PROBABLY DENSE IN MANY
AREAS. WE HAVE ADDED DENSE FOG POTENTIAL TO THE HAZARDOUS WEATHER
OUTLOOK. OTHERWISE...THE WARM FRONT MAY MOVE INTO THE OUR SOUTHERN
GEORGIA ZONES BY DAYBREAK ON TUE AND A CONTINUATION OF PERIODIC
DRIZZLE AND MAINLY LIGHT RAIN SHOWERS. MID LEVELS LOOK PRETTY
UNSTABLE BUT ELEVATED THUNDER RISK IS PRETTY LOW AS MODELS SHOW
MID LEVEL NVA AND SOMEWHAT DRIER AIR ALOFT. TEMPS OVERNIGHT SHOULD
BE STEADY AND EVEN RISE LATE. POPS MAINLY IN THE CHANCE RANGE.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
TUESDAY AND WEDNESDAY...A LARGE SYNOPTIC SCALE TROUGH OF LOW PRESSURE
WILL DIG OVER THE CENTRAL UNITED STATES...SPAWNING A SFC LOW OVER
THE NORTHERN GULF OF MEXICO TUESDAY THAT QUICKLY DEEPENS AND LIFTS
NORTH/NORTHEAST WITH A COLD FRONT EXTENDING SOUTHWARD INTO WEDNESDAY.
A STRONG H5 SHORTWAVE ROUNDING THE BASE OF THE HIGH AMPLITUDE TROUGH
AS WELL AS A STRONG LOW/MID/UPPER LVL JET WILL LIKELY FORCE THE
SOUTHWARD EXTENDING COLD FRONT TO THE EAST...EVENTUALLY PUSHING IT
THROUGH THE FORECAST AREA LATE WEDNESDAY AFTERNOON INTO EARLY
WEDNESDAY NIGHT.
AHEAD OF THE COLD FRONT...A DEEP PLUME OF MOISTURE CHARACTERIZED BY
PWATS UP TO 1.8-1.9 INCHES WILL ADVECT TO THE AREA AS A WARM FRONT
BEGINS TO LIFT NORTH AND ENCOUNTERS THE PERSISTENT WEDGE INLAND.
WIDESPREAD SHOWERS WILL THEREFORE REMAIN IN THE FORECAST FOR MOST
AREAS. MODELS NOW SUGGEST THE WARM FRONT WILL LIFT A BIT FURTHER
NORTH ON TUESDAY THAN PREVIOUSLY NOTED...TRYING TO SCOUR OUT WHAT IS
LEFT OF WEDGE OF HIGH PRESSURE INLAND. HOWEVER...WE STILL BELIEVE
THIS IS A BIT AGGRESSIVE WITH THE WEDGE CURRENTLY IN PLACE SO HAVE
MAINTAINED TEMPS A FEW DEGREES BELOW GUIDANCE...ESPECIALLY INLAND
WHERE THE WEDGE SHOULD HOLD DURING PEAK HEATING HOURS TUESDAY
AFTERNOON. GIVEN THIS SCENARIO...SLIGHT CHANCES OF THUNDERSTORMS
WILL REMAIN IN THE FORECAST TUESDAY AFTERNOON/EVENING WHERE SBCAPES
APPROACH 800 J/KG AND MODEST MID LVL LAPSE RATES OCCUR SOUTH OF THE
WARM FRONT. WE COULD SEE SOME ENHANCEMENT TO THUNDERSTORM ACTIVITY
AS SEVERAL MID LVL WAVES OF ENERGY ADVANCE OVER THE AREA TUESDAY
AFTERNOON AND/OR EVENING. THUNDERSTORMS MAY ALSO NEED TO BE INCLUDED
IN FUTURE FORECASTS FOR INLAND AREAS SHOULD ELEVATED INSTABILITY
CONTINUE TO INCREASE OVER THE WEDGE. IN GENERAL...AFTERNOON HIGH
TEMPS SHOULD RANGE IN THE LOW/MID 60S INLAND TO UPPER 60S IN
SOUTHEAST GEORGIA TUESDAY AFTERNOON.
AS DIURNAL HEATING IS LOST TUESDAY NIGHT...THUNDERSTORM CHANCES
SHOULD MAINLY OCCUR OFFSHORE...BUT DEEP MOISTURE WILL LIKELY
MAINTAIN WIDESPREAD SHOWERS WHILE FORCING INCREASES FROM THE
WEST. TUESDAY NIGHT TEMPS WILL BE MILD WITHIN A SOUTHERLY FLOW AHEAD
OF THE APPROACHING COLD FRONT...WITH LOWS ONLY DIPPING INTO THE
UPPER 50S TO LOWER 60S.
WIDESPREAD CLOUD COVER AND ONGOING SHOWERS SHOULD LIMIT THE OVERALL
THERMODYNAMIC ENVIRONMENT ON WEDNESDAY. HOWEVER...STRONG WIND FIELDS
JUST OFF THE SFC COULD RESULT IN SOME GUSTY WINDS CONDITIONS AS
TEMPS APPROACH 70 DEGREES WEDNESDAY AFTERNOON. A SLIGHT CHANCE OF
THUNDERSTORMS WILL REMAIN IN THE FORECAST FOR ALL AREAS GIVEN THE
AMOUNT OF MID/UPPER LVL FORCING SHIFTING OVER THE REGION. HOWEVER
THE BEST CHANCES OF THUNDERSTORMS SHOULD OCCUR AS THE COLD FRONT
PUSHES INTO THE AREA WEDNESDAY EVENING INTO EARLY WEDNESDAY NIGHT.
GUSTY WINDS SHOULD CONTINUE FOR A FEW HOURS WEDNESDAY NIGHT AS
STRONG COLD AIR ADVECTION OCCURS BEHIND THE FRONT. CONDITIONS WILL
THEN QUICKLY DRY OUT FROM WEST TO EAST LATE WEDNESDAY NIGHT AS HIGH
PRESSURE BEGINS TO PUSH INTO THE REGION.
THURSDAY...MUCH DRYER/QUIET WEATHER CONDITIONS ARE EXPECTED AS THE
MID LVL TROUGH AXIS SHIFTS OFFSHORE AND HIGH PRESSURE SETTLES OVER
THE SOUTHEASTERN UNITED STATES. DESPITE A RETURN TO MOSTLY SUNNY
SKIES...TEMPS WILL REMAIN COOLER AS COLD AIR ADVECTS OVER THE AREA.
IN GENERAL...AFTERNOON TEMPS SHOULD RANGE IN THE MID TO UPPER 50S
OVER MOST AREAS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
QUIET WEATHER WILL PREVAIL INTO THE WEEKEND AS HIGH PRESSURE BECOMES
CENTERED OVER THE SOUTHEASTERN UNITED STATES. OVERALL HIGH TEMPS
SHOULD GRADUALLY WARM EACH DAY AS HIGH PRESSURE CONTINUES TO SLIDE
EAST LATE WEEKEND...ALLOWING A LIGHT SOUTHERLY FLOW TO RETURN TO THE
AREA. IN GENERAL...TEMPS WILL REACH THE LOWER 60S ON FRIDAY...THEN
TO THE MID 60S ON SATURDAY. OVERNIGHT LOWS SHOULD RANGE IN THE THE
LOW/MID 40S INTO THE WEEKEND. THE NEXT BEST CHANCE OF PRECIP SHOULD
OCCUR EARLY NEXT WEEK WITH A COLD FRONT THAT APPROACHES THE REGION.
HOWEVER...CONFIDENCE IN TIMING AND STRENGTH OF PATTERN IS QUITE LOW
GIVEN LARGE DISCREPANCIES IN MODEL SOLUTIONS.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
WE EXPECT BOTH TERMINALS TO REMAIN TANKED AT IFR OR LOWER THROUGH
THE MAJORITY OF THE 18Z TAF PERIOD. WIDESPREAD MODERATE TO HEAVY
RAIN WILL SPREAD ACROSS BOTH TERMINALS THIS AFTERNOON WITH
OCCASIONAL VSBY REDUCTIONS. A STRONG WEDGE OF HIGH PRESSURE WILL
REMAIN IN PLACE AT LEAST THROUGH TONIGHT. HOWEVER A WARM FRONT IS
EXPECTED TO LIFT NORTH LATE TONIGHT WITH INCREASING LOW- LEVEL
MOISTURE APPROACHING THE TERMINALS. ONGOING LIFR STRATUS WILL
LIKELY BUILD-DOWN THIS EVENING WITH VSBYS DROPPING TO LIFR.
CONDITIONS DO NOT SUPPORT MUCH RECOVERY ON TUESDAY...THOUGH SFC
VSBYS SHOULD IMPROVE A FEW HRS AFTER DAYBREAK. IFR OR LOWER
CEILINGS LIKELY TO PERSIST THROUGH MUCH OF THE DAY TUESDAY.
EXTENDED AVIATION OUTLOOK...PERIODS OF MVFR OR LOWER CONDITIONS ARE
LIKELY LIKELY TUESDAY AFTERNOON INTO WEDNESDAY AFTERNOON AS A STRONG
COLD FRONT APPROACHES FROM THE WEST WITH SHOWERS AND THUNDERSTORMS.
LLWS WILL BE A POSSIBILITY TUESDAY NIGHT AS STRONGER WIND FIELDS
SHIFT OVER THE AREA IN ADVANCE OF THE FRONT. MVFR OR LOWER
CONDITIONS AND GUSTY WINDS ARE EXPECTED UNTIL THE TIME OF FRONTAL
PASSAGE SOMETIME WEDNESDAY EVENING INTO EARLY WEDNESDAY NIGHT. VFR
CONDITIONS SHOULD THEN PREVAIL BY DAYBREAK THURSDAY.
&&
.MARINE...
MARINE CONDITIONS ARE SLOWLY IMPROVING THIS MORNING. THE GRADIENT
HAS WEAKENED ENOUGH TO ALLOW THE SMALL CRAFT ADVISORIES TO DROP
OFF AROUND DAYBREAK. THE DENSE FOG IN CHARLESTON HARBOR AND
IMMEDIATE CHARLESTON COASTAL WATERS HAS LIFTED TO A LOW STRATUS
DECK. CHS PILOT OFFICE REPORTS VSBYS AROUND 3 NM AS OF 9 AM WITH
THE PORT REOPENED TO COMMERCIAL SHIPPING TRAFFIC. WE DROPPED THE
DENSE FOG ADVISORY A BIT EARLIER. TONIGHT THERE COULD BE A
RESURGENCE IN FOG AS THE STRATUS DECK BUILDS DOWN AND ANOTHER
DENSE FOG ADVISORY IS POSSIBLE.
TUESDAY...CONDITIONS SHOULD REMAIN JUST BELOW SMALL CRAFT ADVISORY
LEVELS AS A WEDGE OF HIGH PRESSURE PERSISTS INLAND WHILE A WARM
FRONT TRIES TO LIFT NORTH DURING THE AFTERNOON. SHOWERS AND/OR
THUNDERSTORMS ARE ANTICIPATED OVER THE WATERS THROUGH THE DAY. IN
GENERAL...WINDS SHOULD PEAK BETWEEN 15-20 KT WITH SEAS UP TO 3-4
FT...HIGHEST IN OFFSHORE GEORGIA WATERS.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...CONDITIONS WILL LIKELY
DETERIORATE LATE TUESDAY NIGHT INTO EARLY WEDNESDAY AS THE PRESSURE
GRADIENT TIGHTENS AND WARMER AIR PROMOTES MIXING AHEAD OF A COLD
FRONT THAT EVENTUALLY SHIFTS OVER THE WATERS WEDNESDAY
EVENING/NIGHT. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE OVER MOST
WATERS AHEAD OF THE FRONT...WHILE WINDS AND SEAS INCREASE/BUILD
WITHIN A SOUTHERLY FLOW. AT THIS TIME...CONDITIONS SHOULD REACH
SMALL CRAFT ADVISORY LEVELS FOR ALL WATERS STARTING LATE TUESDAY
NIGHT. SEAS WILL ALSO BUILD UPWARDS TO 5-8 FT INTO WEDNESDAY
AFTERNOON BEFORE THE COLD FRONT SHIFTS OFFSHORE. THERE IS STILL A
CHANCE OF GALE FORCE WIND GUSTS LATE WEDNESDAY NIGHT INTO EARLY
THURSDAY AS STRONG COLD AIR ADVECTION OCCURS BEHIND THE FRONT...BUT
CHANCES APPEAR HIGHEST IN OUTER GEORGIA WATERS. A GALE WATCH/WARNING
COULD EVENTUALLY BE NEEDED AS WINDS GUST TO 30-35 KT AWAY FROM THE
COAST.
THURSDAY AFTERNOON THROUGH SATURDAY...CONDITIONS WILL IMPROVE
QUICKLY OVER ALL WATERS AS HIGH PRESSURE BECOMES CENTERED OVER THE
SOUTHEAST. WINDS/SEAS SHOULD LOWER BELOW SMALL CRAFT ADVISORY LEVELS
FOR ALL WATERS THURSDAY AFTERNOON...THEN CONTINUE TO IMPROVE
THROUGH THE WEEKEND AS THE CENTER OF HIGH PRESSURE SLIDES OFFSHORE.
SEA FOG...MARINERS ARE ADVISED THAT LOW STRATUS DECKS AND PERIODS OF
RAIN OR DRIZZLE WILL EQUATE TO REDUCED VISIBILITIES UNTIL WEDNESDAY...
BUT THE BEST CHANCE OF CLASSIC SEA FOG COULD DEVELOP AS WARMER AIR
ARRIVES ATOP MID/UPPER 50 SHELF WATER TEMPS EARLY TUESDAY PRIOR TO
WINDS INCREASING ENOUGH TO SCOUR IT OUT TUESDAY NIGHT.
&&
.TIDES/COASTAL FLOODING...
NNE FLOW PUSHED THE CHARLESTON TIDE ABOVE 7.4 FT THIS MORNING...
MORE THAN 1 FT ANOMALY. AMAZING WHAT THE EKMAN EFFECT CAN DO TO
TIDES. THE TUESDAY MORNING HIGH TIDE IS PREDICTED AT 6.4 FT MLLW.
SIMILAR WINDS EXPECTED THEN...PERHAPS SLIGHTLY WEAKER. NEVERTHELESS
CONDITIONS LOOK PRETTY FAVORABLE FOR ANOTHER BOUT OF SHALLOW
COASTAL FLOODING SO WE ARE MENTIONING THIS IN THE HAZARDOUS
WEATHER OUTLOOK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JRL
SHORT TERM...DPB
LONG TERM...DPB
AVIATION...JRL
MARINE...DPB/JRL
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1046 AM EST MON DEC 22 2014
.SYNOPSIS...
UNSETTLED WEATHER IS EXPECTED THROUGH TUESDAY NIGHT AS SEVERAL
DISTURBANCES MOVE OVER THE REGION. A STRONG COLD FRONT WILL THEN
MOVE THROUGH THE AREA WEDNESDAY EVENING. DRY HIGH PRESSURE WILL
SETTLE OVER THE SOUTHEAST INTO THE WEEKEND. ANOTHER COLD FRONT
COULD SHIFT THROUGH THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A MUCKY PATTERN WILL CONTINUE FOR YET ANOTHER DAY AS A STRONG
WEDGE OF HIGH PRESSURE REMAINS OVER THE MID-ATLANTIC REGION AND
EXTENDS DOWN THE EASTERN SEABOARD AS FAR SOUTH AS SOUTHERN GA. A
DEEP UPPER LEVEL TROUGH OVER THE CENTRAL UNITED STATES CONTINUES
TO PROVIDE A STEADY FEED OF SHORTWAVE ENERGY ACROSS THE SOUTHEAST
STATES. INITIALLY IT SEEMED AS THOUGH THE JET DIVERGENCE WAS GOING
TO WEAKEN TODAY AND THE STRONGEST SHORTWAVE ENERGY WOULD SHIFT
NORTHEAST OF THE REGION. HOWEVER WE HAVE NOTED A FAIRLY WIDESPREAD
AREA OF RAIN MOVING OUT OF CENTRAL GA INTO OUR FORECAST AREA THIS
MORNING. THIS IS ASSOCIATED WITH A WEAK SLUG OF ISENTROPIC OMEGA
THAT THE 12Z NAM FINALLY PICKED UP ON. THE LATEST HRRR HAS ALSO
CAUGHT ONTO THE INLAND PRECIP WHICH SHOULD PROGRESS NORTHEAST
THROUGH THE AREA THIS AFTERNOON. SIGNIFICANT CHANGES TO THE POP
GRIDS WERE IN ORDER THIS MORNING. WE ARE NOW CARRYING LIKELY OR
CATEGORICAL POPS OVER MANY LAND AREAS THROUGH EARLY AFTERNOON...
GRADUALLY TAPERING BACK LATE THIS AFTERNOON ONCE THE BEST FORCING
MOVES AWAY TO THE NORTHEAST. DENSE OVERCAST AND STEADY RAIN WILL
KEEP TEMPERATURES FAIRLY STEADY IN THE UPPER 40S TO LOWER 50S.
SOUNDINGS SHOW LOW-MID 50S AIR AT THE SURFACE TODAY AND THIS
EVENING AND MID 60S AIR AT 300-400 FT WHICH IS PRIME FOR STRATUS
BUILDING DOWN GIVEN A SETUP WITH LIGHTER WINDS IN THE BOUNDARY
LAYER. THE STORY TONIGHT SHOULD BE FOG...PROBABLY DENSE IN MANY
AREAS. WE HAVE ADDED DENSE FOG POTENTIAL TO THE HAZARDOUS WEATHER
OUTLOOK. OTHERWISE...THE WARM FRONT MAY MOVE INTO THE OUR SOUTHERN
GEORGIA ZONES BY DAYBREAK ON TUE AND A CONTINUATION OF PERIODIC
DRIZZLE AND MAINLY LIGHT RAIN SHOWERS. MID LEVELS LOOK PRETTY
UNSTABLE BUT ELEVATED THUNDER RISK IS PRETTY LOW AS MODELS SHOW
MID LEVEL NVA AND SOMEWHAT DRIER AIR ALOFT. TEMPS OVERNIGHT SHOULD
BE STEADY AND EVEN RISE LATE. POPS MAINLY IN THE CHANCE RANGE.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
TUESDAY AND WEDNESDAY...A LARGE SYNOPTIC SCALE TROUGH OF LOW PRESSURE
WILL DIG OVER THE CENTRAL UNITED STATES...SPAWNING A SFC LOW OVER
THE NORTHERN GULF OF MEXICO TUESDAY THAT QUICKLY DEEPENS AND LIFTS
NORTH/NORTHEAST WITH A COLD FRONT EXTENDING SOUTHWARD INTO WEDNESDAY.
A STRONG H5 SHORTWAVE ROUNDING THE BASE OF THE HIGH AMPLITUDE TROUGH
AS WELL AS A STRONG LOW/MID/UPPER LVL JET WILL LIKELY FORCE THE
SOUTHWARD EXTENDING COLD FRONT TO THE EAST...EVENTUALLY PUSHING IT
THROUGH THE FORECAST AREA LATE WEDNESDAY AFTERNOON INTO EARLY
WEDNESDAY NIGHT.
AHEAD OF THE COLD FRONT...A DEEP PLUME OF MOISTURE CHARACTERIZED BY
PWATS UP TO 1.8-1.9 INCHES WILL ADVECT TO THE AREA AS A WARM FRONT
BEGINS TO LIFT NORTH AND ENCOUNTERS THE PERSISTENT WEDGE INLAND.
WIDESPREAD SHOWERS WILL THEREFORE REMAIN IN THE FORECAST FOR MOST
AREAS. MODELS NOW SUGGEST THE WARM FRONT WILL LIFT A BIT FURTHER
NORTH ON TUESDAY THAN PREVIOUSLY NOTED...TRYING TO SCOUR OUT WHAT IS
LEFT OF WEDGE OF HIGH PRESSURE INLAND. HOWEVER...WE STILL BELIEVE
THIS IS A BIT AGGRESSIVE WITH THE WEDGE CURRENTLY IN PLACE SO HAVE
MAINTAINED TEMPS A FEW DEGREES BELOW GUIDANCE...ESPECIALLY INLAND
WHERE THE WEDGE SHOULD HOLD DURING PEAK HEATING HOURS TUESDAY
AFTERNOON. GIVEN THIS SCENARIO...SLIGHT CHANCES OF THUNDERSTORMS
WILL REMAIN IN THE FORECAST TUESDAY AFTERNOON/EVENING WHERE SBCAPES
APPROACH 800 J/KG AND MODEST MID LVL LAPSE RATES OCCUR SOUTH OF THE
WARM FRONT. WE COULD SEE SOME ENHANCEMENT TO THUNDERSTORM ACTIVITY
AS SEVERAL MID LVL WAVES OF ENERGY ADVANCE OVER THE AREA TUESDAY
AFTERNOON AND/OR EVENING. THUNDERSTORMS MAY ALSO NEED TO BE INCLUDED
IN FUTURE FORECASTS FOR INLAND AREAS SHOULD ELEVATED INSTABILITY
CONTINUE TO INCREASE OVER THE WEDGE. IN GENERAL...AFTERNOON HIGH
TEMPS SHOULD RANGE IN THE LOW/MID 60S INLAND TO UPPER 60S IN
SOUTHEAST GEORGIA TUESDAY AFTERNOON.
AS DIURNAL HEATING IS LOST TUESDAY NIGHT...THUNDERSTORM CHANCES
SHOULD MAINLY OCCUR OFFSHORE...BUT DEEP MOISTURE WILL LIKELY
MAINTAIN WIDESPREAD SHOWERS WHILE FORCING INCREASES FROM THE
WEST. TUESDAY NIGHT TEMPS WILL BE MILD WITHIN A SOUTHERLY FLOW AHEAD
OF THE APPROACHING COLD FRONT...WITH LOWS ONLY DIPPING INTO THE
UPPER 50S TO LOWER 60S.
WIDESPREAD CLOUD COVER AND ONGOING SHOWERS SHOULD LIMIT THE OVERALL
THERMODYNAMIC ENVIRONMENT ON WEDNESDAY. HOWEVER...STRONG WIND FIELDS
JUST OFF THE SFC COULD RESULT IN SOME GUSTY WINDS CONDITIONS AS
TEMPS APPROACH 70 DEGREES WEDNESDAY AFTERNOON. A SLIGHT CHANCE OF
THUNDERSTORMS WILL REMAIN IN THE FORECAST FOR ALL AREAS GIVEN THE
AMOUNT OF MID/UPPER LVL FORCING SHIFTING OVER THE REGION. HOWEVER
THE BEST CHANCES OF THUNDERSTORMS SHOULD OCCUR AS THE COLD FRONT
PUSHES INTO THE AREA WEDNESDAY EVENING INTO EARLY WEDNESDAY NIGHT.
GUSTY WINDS SHOULD CONTINUE FOR A FEW HOURS WEDNESDAY NIGHT AS
STRONG COLD AIR ADVECTION OCCURS BEHIND THE FRONT. CONDITIONS WILL
THEN QUICKLY DRY OUT FROM WEST TO EAST LATE WEDNESDAY NIGHT AS HIGH
PRESSURE BEGINS TO PUSH INTO THE REGION.
THURSDAY...MUCH DRYER/QUIET WEATHER CONDITIONS ARE EXPECTED AS THE
MID LVL TROUGH AXIS SHIFTS OFFSHORE AND HIGH PRESSURE SETTLES OVER
THE SOUTHEASTERN UNITED STATES. DESPITE A RETURN TO MOSTLY SUNNY
SKIES...TEMPS WILL REMAIN COOLER AS COLD AIR ADVECTS OVER THE AREA.
IN GENERAL...AFTERNOON TEMPS SHOULD RANGE IN THE MID TO UPPER 50S
OVER MOST AREAS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
QUIET WEATHER WILL PREVAIL INTO THE WEEKEND AS HIGH PRESSURE BECOMES
CENTERED OVER THE SOUTHEASTERN UNITED STATES. OVERALL HIGH TEMPS
SHOULD GRADUALLY WARM EACH DAY AS HIGH PRESSURE CONTINUES TO SLIDE
EAST LATE WEEKEND...ALLOWING A LIGHT SOUTHERLY FLOW TO RETURN TO THE
AREA. IN GENERAL...TEMPS WILL REACH THE LOWER 60S ON FRIDAY...THEN
TO THE MID 60S ON SATURDAY. OVERNIGHT LOWS SHOULD RANGE IN THE THE
LOW/MID 40S INTO THE WEEKEND. THE NEXT BEST CHANCE OF PRECIP SHOULD
OCCUR EARLY NEXT WEEK WITH A COLD FRONT THAT APPROACHES THE REGION.
HOWEVER...CONFIDENCE IN TIMING AND STRENGTH OF PATTERN IS QUITE LOW
GIVEN LARGE DISCREPANCIES IN MODEL SOLUTIONS.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
KSAV...THE TERMINAL MOST LIKELY WILL REMAIN TANKED AS A STRONG WEDGE
INVERSION PERSISTS JUST OFF THE DECK AND GENERATES IFR OR LOWER
CONDITIONS THROUGH 06Z TUESDAY. IN ADDITION...MID AND UPPER LEVEL
ENERGY AND THE PROXIMITY TO A COASTAL WARM FRONT NEAR THE GULF
STREAM WILL PRODUCE PERIODS OF RAIN OR DRIZZLE.
KCHS...LIFR CONDITIONS DEVELOPING AT 09Z...DENSE FOG MAY ENSUE
AS CIGS DOWN TO 200 FT AND VSBYS AT 1 NM. THE NEXT 24 HOURS WILL
SEE LOW CIGS AND PERHAPS PERIODS OF FOGGY CONDITIONS AS STRATUS
CLOUDS REMAINED PINNED IN THE FIRST FEW HUNDRED FEET OF THE
ATMOSPHERE. OCCASIONAL DRIZZLE LIKELY WITH A CHANCE OF SHOWERS.
IFR OR LOWER CONDITIONS PREVAIL THROUGH THE TAF PERIOD.
EXTENDED AVIATION OUTLOOK...PERIODS OF MVFR OR LOWER CONDITIONS ARE
LIKELY LIKELY TUESDAY AFTERNOON INTO WEDNESDAY AFTERNOON AS A STRONG
COLD FRONT APPROACHES FROM THE WEST WITH SHOWERS AND THUNDERSTORMS.
LLWS WILL BE A POSSIBILITY TUESDAY NIGHT AS STRONGER WIND FIELDS
SHIFT OVER THE AREA IN ADVANCE OF THE FRONT. MVFR OR LOWER
CONDITIONS AND GUSTY WINDS ARE EXPECTED UNTIL THE TIME OF FRONTAL
PASSAGE SOMETIME WEDNESDAY EVENING INTO EARLY WEDNESDAY NIGHT. VFR
CONDITIONS SHOULD THEN PREVAIL BY DAYBREAK THURSDAY.
&&
.MARINE...
MARINE CONDITIONS ARE SLOWLY IMPROVING THIS MORNING. THE GRADIENT
HAS WEAKENED ENOUGH TO ALLOW THE SMALL CRAFT ADVISORIES TO DROP
OFF AROUND DAYBREAK. THE DENSE FOG IN CHARLESTON HARBOR AND
IMMEDIATE CHARLESTON COASTAL WATERS HAS LIFTED TO A LOW STRATUS
DECK. CHS PILOT OFFICE REPORTS VSBYS AROUND 3 NM AS OF 9 AM WITH
THE PORT REOPENED TO COMMERCIAL SHIPPING TRAFFIC. WE DROPPED THE
DENSE FOG ADVISORY A BIT EARLIER. TONIGHT THERE COULD BE A
RESURGENCE IN FOG AS THE STRATUS DECK BUILDS DOWN AND ANOTHER
DENSE FOG ADVISORY IS POSSIBLE.
TUESDAY...CONDITIONS SHOULD REMAIN JUST BELOW SMALL CRAFT ADVISORY
LEVELS AS A WEDGE OF HIGH PRESSURE PERSISTS INLAND WHILE A WARM
FRONT TRIES TO LIFT NORTH DURING THE AFTERNOON. SHOWERS AND/OR
THUNDERSTORMS ARE ANTICIPATED OVER THE WATERS THROUGH THE DAY. IN
GENERAL...WINDS SHOULD PEAK BETWEEN 15-20 KT WITH SEAS UP TO 3-4
FT...HIGHEST IN OFFSHORE GEORGIA WATERS.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...CONDITIONS WILL LIKELY
DETERIORATE LATE TUESDAY NIGHT INTO EARLY WEDNESDAY AS THE PRESSURE
GRADIENT TIGHTENS AND WARMER AIR PROMOTES MIXING AHEAD OF A COLD
FRONT THAT EVENTUALLY SHIFTS OVER THE WATERS WEDNESDAY
EVENING/NIGHT. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE OVER MOST
WATERS AHEAD OF THE FRONT...WHILE WINDS AND SEAS INCREASE/BUILD
WITHIN A SOUTHERLY FLOW. AT THIS TIME...CONDITIONS SHOULD REACH
SMALL CRAFT ADVISORY LEVELS FOR ALL WATERS STARTING LATE TUESDAY
NIGHT. SEAS WILL ALSO BUILD UPWARDS TO 5-8 FT INTO WEDNESDAY
AFTERNOON BEFORE THE COLD FRONT SHIFTS OFFSHORE. THERE IS STILL A
CHANCE OF GALE FORCE WIND GUSTS LATE WEDNESDAY NIGHT INTO EARLY
THURSDAY AS STRONG COLD AIR ADVECTION OCCURS BEHIND THE FRONT...BUT
CHANCES APPEAR HIGHEST IN OUTER GEORGIA WATERS. A GALE WATCH/WARNING
COULD EVENTUALLY BE NEEDED AS WINDS GUST TO 30-35 KT AWAY FROM THE
COAST.
THURSDAY AFTERNOON THROUGH SATURDAY...CONDITIONS WILL IMPROVE
QUICKLY OVER ALL WATERS AS HIGH PRESSURE BECOMES CENTERED OVER THE
SOUTHEAST. WINDS/SEAS SHOULD LOWER BELOW SMALL CRAFT ADVISORY LEVELS
FOR ALL WATERS THURSDAY AFTERNOON...THEN CONTINUE TO IMPROVE
THROUGH THE WEEKEND AS THE CENTER OF HIGH PRESSURE SLIDES OFFSHORE.
SEA FOG...MARINERS ARE ADVISED THAT LOW STRATUS DECKS AND PERIODS OF
RAIN OR DRIZZLE WILL EQUATE TO REDUCED VISIBILITIES UNTIL WEDNESDAY...
BUT THE BEST CHANCE OF CLASSIC SEA FOG COULD DEVELOP AS WARMER AIR
ARRIVES ATOP MID/UPPER 50 SHELF WATER TEMPS EARLY TUESDAY PRIOR TO
WINDS INCREASING ENOUGH TO SCOUR IT OUT TUESDAY NIGHT.
&&
.TIDES/COASTAL FLOODING...
NNE FLOW PUSHED THE CHARLESTON TIDE ABOVE 7.4 FT THIS MORNING...
MORE THAN 1 FT ANOMALY. AMAZING WHAT THE EKMAN EFFECT CAN DO TO
TIDES. THE TUESDAY MORNING HIGH TIDE IS PREDICTED AT 6.4 FT MLLW.
SIMILAR WINDS EXPECTED THEN...PERHAPS SLIGHTLY WEAKER. NEVERTHELESS
CONDITIONS LOOK PRETTY FAVORABLE FOR ANOTHER BOUT OF SHALLOW
COASTAL FLOODING SO WE ARE MENTIONING THIS IN THE HAZARDOUS
WEATHER OUTLOOK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JRL
SHORT TERM...DPB
LONG TERM...DPB
AVIATION...
MARINE...DPB/JRL
TIDES/COASTAL FLOODING...JRL
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
306 PM CST MON DEC 22 2014
.SHORT TERM...
1227 PM CST
TONIGHT THROUGH CHRISTMAS DAY...
MAIN CHALLENGES FOR TONIGHT WILL BE ON PLACEMENT OF PRECIP ALONG
WITH HOW MUCH RAIN WILL FALL ACROSS THE FORECAST AREA. THE
NORTHERN STREAM SFC LOW HAS BECOME WRAPPED UP ACROSS THE
DAKOTAS...WITH THE MID-LVL TROUGH AXIS STRETCHING SOUTH THROUGH
THE SOUTHERN PLAINS. LLVL FLOW ACROSS THE FORECAST AREA HAS BECOME
MORE EASTERLY...WITH A FEED OF SOME SLIGHTLY DRIER AIR AT THE SFC
INTO NORTHERN IL/NORTHWEST IN. THIS HAS BEEN ABLE TO DELAY THE
ONSET OF STEADY PRECIP UNTIL LATER THIS AFTN. SFC TEMPS HAVE BEEN
SLOW TO WARM...AND LATEST GUIDANCE INDICATES THAT MAX TEMPS MAY
NOT OCCUR UNTIL JUST AFT 00Z AS A STEADY CONVEYOR OF WARMER/MOIST
AIR ADVECTS NORTH.
LOCAL SOLUTIONS BRING THE BETTER SLUG OF PRECIP INTO THE FORECAST
AREA THIS EVENING...THEN SLOWLY LIFT THE STEADIER RAIN NORTH
OVERNIGHT. QPF TOTALS HAVE DECREASED FROM EARLIER SOLUTIONS...BUT
HAVE ONLY MADE MINOR ADJUSTMENTS TO THE GOING FORECAST. THE SFC LOW
OVER THE DAKOTAS WILL BE SLIDING SOUTHEAST TOWARDS SOUTHEAST IOWA
OVERNIGHT...WITH A DRY WEDGE BECOMING ENTRAINED OVER MISSOURI.
GUIDANCE HAS BEEN LEANING TOWARDS POSSIBLY AN EARLIER ARRIVAL OF THE
DRY SLOT INTO THE FORECAST AREA JUST BEFORE DAYBREAK TUE. GIVEN THE
CONTINUED UNCERTAINTIES ON TRACK/PLACEMENT OF THE LOW...HAVE HELD
ONTO SOME LGT RAIN AT DAYBREAK THEN LIFT THE PRECIP SHIELD NORTH OF
INTO WISC BY MID-MORNING TUE. TEMPS OVERNIGHT MON SHUD BE NEARLY
STEADY...THEN AFT MIDNIGHT WITH A 850MB THERMAL RIDGE OF 3-6 DEG C
LIFTING NORTH EXPECT TEMPS TO BE SLOWLY RISING INTO THE LOW 40S.
TUE EXPECT THE SFC LOW TO BE SLOWLY WEAKENING ACROSS SOUTHWEST
WISC...WITH THE MID-LVL TROUGH AXIS EJECTING THE SECONDARY SFC LOW
ALONG THE WESTERN GULF. THIS SECONDARY LOW IS THE MAIN CONCERN FOR
WED AFTN-WED NGT ACROSS OUR REGION. THE DRY WEDGE SHUD KEEP PRECIP
WEST/NORTH OF THE FORECAST AREA THRU TUE MORNING...THEN WRAP AROUND
MOISTURE WILL BRING LGT RAIN BACK INTO THE AREA TUE AFTN/EVE. TEMPS
SHUD WARM INTO THE MID/UPR 40S...POSSIBLY TOUCHING 50 DEGREES IN THE
SOUTHEAST CWFA. THE SOUTHERN STREAM LOW WILL BE RAPIDLY DEEPENING
AND LIFTING NORTH ACROSS THE TENN VALLEY WED MORNING...THEN IT
BECOMES A CHALLENGE ON THE PLACEMENT OF THE LOW BEYOND WED MORNING.
GUIDANCE CONTINUES TO SHOW CORRECTIONS...WITH A FEW SOLUTIONS
BRINGING THE LOW NORTH INTO NORTHEAST IN AND A FEW FURTHER EAST.
THIS WILL BE A KEY PLAYER ON THE PLACEMENT OF THE POTENTIAL
DEFORMATION ZONE WHICH COULD BRING ACCUM SNOW TO THE FORECAST AREA
WED AFTN/EVE. TEMPS WILL BE FALLING DURING THE DAY WED...AND WITH
THE INCREASED FORCING...THIS COULD BR STRONG ENOUGH TO OVERCOME THE
WARMER AIR AT THE SFC AND ALLOW RAIN TO QUICKLY CHANGE TO SNOW AND
START ACCUMULATING. GEFS ENSEMBLES ARE BEGINNING TO DEMONSTRATE A
WEAK EASTERLY LLVL JET AT 850MB LIFTING NORTHEAST OVER THE FORECAST
AREA WED AFTN/EARLY EVE...WHICH WOULD SUPPORT THE IDEA OF A
DEFORMATION SNOW BAND FOR THE CENTRAL/EASTERN CWFA. CONSIDERABLE
UNCERTAINTY REMAINS WITH THIS SYSTEM...BUT EITHER WAY IT WILL IMPACT
A PORTION OF THE GREAT LAKES REGION ON ONE OF THE BUSIEST TRAVEL
DAYS OF THE YEAR.
FOR CHRISTMAS DAY...THE DOWNSTREAM RIDGE OVER THE CANADIAN MARITIME
WILL BEGIN TO WEAKEN AND ALLOW FOR THE 500MB TROUGH TO PUSH EAST OF
THE GREAT LAKES...LIFTING THE DEEPER MOISTURE/PRECIP NORTHEAST WITH
IT. MOST GUIDANCE COMES INTO SLIGHTLY BETTER AGREEMENT FOR HIGHS
ARND THE MID/UPR 30S...WITH POSSIBLY THINNING CLOUD COVER.
BEACHLER
&&
.LONG TERM...
252 PM CST
FRIDAY THROUGH MONDAY...
MAIN FORECAST CONCERNS THIS PERIOD SURROUND A PAIR OF STORM SYSTEMS.
THE FIRST TO PASS TO THE NORTH OF THE AREA FRIDAY-FRIDAY NIGHT AND
THE SECOND TO PASS TO THE SOUTH AND EAST (SHOULD CURRENT TRENDS
CONTINUE) ON SUNDAY. FIRST SURFACE LOW DEVELOPS OVER THE CENTRAL
PLAINS THURS NIGHT IN RESPONSE TO THE DIGGING UPPER TROF OVER THE
WESTERN U.S. MODELS SHOWING NRN IL GENERALLY DRY FRIDAY DURING THE
DAYTIME HOURS FRIDAY WITH MAX TEMPS RUNNING AROUND 10 DEG ABOVE
AVERAGE. A COLD FRONT THEN SWEEPS ACROSS THE AREA FRIDAY NIGHT
BRINGING A CHANCE OF RAIN OR SNOW.
MEANWHILE A SECONDARY UPPER LEVEL SHORTWAVE ROTATES INTO THE BASE
OF WESTERN U.S. TROUGH THEN ON SATURDAY AMPLIFYING THE SOUTHERN
STREAM. MODELS NOT COMPLETELY RESOLVING THIS SYSTEM YET AND HAVE
LEANED TOWARD MODEL CONSENSUS FOR A FORECAST SCENARIO WHERE A
SHARPER SHORTWAVE HELPS TO ORGANIZE SURFACE LOW PRESSURE NEAR THE
TX/LA GULF COAST SATURDAY. THIS LOW THEN MOVES NORTHEAST ACROSS
THE TN VALLEY AND INTO THE CENTRAL APPLICATIONS SUNDAY. WILL
CONFINE POPS WITH THIS SYSTEM TO JUST THE SOUTHEASTERN COUNTIES OF
THE FORECAST AREA CURRENTLY WITH TEMPS EXPECTED NEAR SEASONAL FOR
THE TIME OF YEAR.
ED F
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* CIGS LOWERING TO IFR/LIFR THIS AFTERNOON/EVENING.
* PERIODS OF RAIN THROUGH TONIGHT
* REDUCED VSBY AT TIMES 1-3 SM.
BMD
//DISCUSSION...UPDATED 18Z...
CONDITIONS ARE STEADILY DETERIORATING ALREADY WITH THE 18Z TAF
ISSUANCE AND EXPECT THIS TREND TO CONTINUE THROUGH THE AFTERNOON
HOURS. A LEAD UPPER LEVEL DISTURBANCE HAS ALLOWED RAIN TO OVERSPREAD
THE TERMINALS LATE THIS MORNING. A FEW SITES HAVE REPORTED A FEW ICE
PELLETS BUT SOUNDINGS INDICATE THE COLUMN WILL QUICKLY WARM AND WILL
NO LONGER SUPPORT FROZEN PRECIPITATION THROUGH THE REMAINDER OF THE
TAF PERIOD. CIGS ARE EXPECTED TO FAIRLY QUICKLY DROP TO IFR EARLY TO
MID AFTERNOON TODAY AND WILL REMAIN THERE OVERNIGHT. BEHIND THE LEAD
WAVE...THERE MAY BE A LULL IN THE PRECIP INTENSITY BUT MOIST
CONDITIONS AND SOME FORCING MAY RESULT IN A VERY LIGHT RAIN OR
DRIZZLE CONTINUING OVERNIGHT. THE MAIN UPPER WAVE AND WARM FRONT
WILL
LIFT ACROSS THE REGION EARLY TUESDAY RESULTING IN PRECIP INTENSITY
INCREASING ONCE AGAIN. ONCE THE WARM FRONT LIFTS NORTH OF THE
TERMINALS...PRECIP SHOULD TAPER AND THERE MAY BE A GRADUAL RISE IN
CIG HEIGHTS BACK INTO MVFR.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN GENERAL CIG TRENDS BUT LOW-MEDIUM CONFIDENCE
IN TIMING.
* LOW CONFIDENCE IN VSBY TRENDS THIS EVENING AND TONIGHT.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...DRY. MAINLY VFR...THOUGH MVFR POSSIBLE LATE.
WEDNESDAY...CHANCE OF RA/SN CHANGING TO SN. IFR LIKELY.
THURSDAY...CHANCE OF MVFR CIGS...MAINLY EARLY.
FRIDAY...CHANCE OF MVFR CIGS. CHANCE OF -RA/-SN
SATURDAY AND SUNDAY...MAINLY VFR.
RATZER
&&
.MARINE...
305 PM CST
LOW PRESSURE OVER THE CENTRAL MISSOURI VALLEY WILL LIFT NORTHEAST
TONIGHT WHILE WEAKENING. THIS WILL RESULT IN BRISK EAST-SOUTHEAST
WINDS OVERNIGHT...WITH GUSTS UP TO 25 TO 30 KT. THE STRONGEST
EASTERLY WINDS WILL SETTLE INTO THE NORTHERN PORTION OF THE LAKE
TUESDAY MORNING...WITH WINDS TURNING SOUTHERLY ON THE SOUTH HALF.
THE LOW PRESSURE WILL DISSIPATE OVER THE NORTHERN PORTION OF THE
LAKE TUESDAY NIGHT...BRINGING QUICKLY DIMINISHING SOUTHERLY WINDS
AND A PERIOD OF LIGHT/VRB OVER THE NORTH.
ATTENTION WILL THEN TURN TO ANOTHER QUICKLY DEVELOPING LOW PRESSURE
OVER THE LOWER OHIO VALLEY ON WEDNESDAY MORNING THAT WILL LIFT NORTH
TO THE CENTRAL GREAT LAKES AND STRENGTHEN RAPIDLY INTO WEDNESDAY
NIGHT...THEN FURTHER INTENSIFY OVER WESTERN/NW QUEBEC ON THURSDAY.
MODELS HAVE COME INTO BETTER AGREEMENT ON THIS OVERALL SCENARIO AND
AM CONCERNED FOR A PERIOD OF GALES ON THE NORTHERN PORTION OF THE
LAKE WEDNESDAY NIGHT CLOSEST TO THE BOMBING LOW. HAVE NOT ISSUED A
WATCH YET DUE TO LOWER CONFIDENCE BUT IF CURRENT TRENDS HOLD WILL
LIKELY NEED A HEADLINE. NORTH-NORTHWEST GALES ARE POSSIBLE ON THE
SOUTH HALF AS WELL DEPENDING ON THE TRACK/STRENGTH OF THE LOW...BUT
CURRENT GUIDANCE SUGGESTS MORE OF A 30 KT PREVAILING/OCNL GALE GUST
SCENARIO. A FAST UPPER PATTERN SUGGESTS A FAIRLY ACTIVE PERIOD
REMAINING OVER THE LAKE INTO THE WEEKEND.
IN THE NEARSHORE...HAD EXTENDED THE SMALL CRAFT FOR THE IL ZONES
THROUGH MID MORNING TUESDAY FOR LINGERING WAVES FROM BRISK
EAST-SOUTHEAST FLOW. WILL LIKELY NEED ANOTHER SMALL CRAFT BY
WEDNESDAY AFTERNOON INTO THURSDAY FOR STRONG WINDS AND BUILDING
WAVES.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM TUESDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
300 PM CST Mon Dec 22 2014
.SHORT TERM...(Tonight)
ISSUED AT 259 PM CST MON DEC 22 2014
Short-wave trough evident on 19z/1pm water vapor imagery over
Kansas/Oklahoma will lift northeastward tonight, reaching central
Illinois by 12z Tue. A large area of light rain associated with
this feature is currently ongoing across the KILX CWA: however,
radar imagery is showing the precip becoming more scattered upstream
across Missouri into southern Illinois. With a continued moist flow
and strong lift ahead of the upper wave, think numerous showers will
re-develop behind the main rain area later this afternoon into the
evening. As a result, will continue to carry categorical PoPs
across the board through the evening. After that, models agree that
a mid-level dry slot will approach from the southwest later tonight
into Tuesday morning. Both the 12z NAM and the 17z HRRR suggest the
showers will taper off and come to an end from southwest to
northeast across the area by dawn Tuesday. Will continue likely to
categorical PoPs along/north of I-74 through the entire night, but
will drop to just chance PoPs further south across the rest of the
CWA after midnight. Southerly winds of 10 to 15 mph will continue
tonight, preventing temps from dropping much. Overnight lows will
be several degrees above numeric guidance, ranging from around 40
across the north to the middle 40s south of I-70.
&&
.LONG TERM...(Tuesday through Monday)
ISSUED AT 259 PM CST MON DEC 22 2014
Model guidance continues to throw us curve balls on how the current
system will depart the area on Christmas Eve. Their spread in the
details and lack of run-to-run consistency continues to make our
confidence in Christmas Eve`s snow potential much lower than
average. There has been more than a trivial trend back toward a
snowier day in the latest runs, although this trend is far from
unanimous. The upshot is that that travel difficulties could exist
for Christmas Eve and it is prudent to monitor later forecasts
closely. While confidence is too low to issue any winter weather
headlines at this time, have issued a Special Weather Statement
highlighting the potential as well as the uncertainty.
However, the main snow threat is still a couple days off. Until
then, we will have to contend with periods of rain, although
confidence is growing that sizable breaks in the rainy periods will
occur. A dry slot wrapping around the vertically stacked
upper/surface low should support most of Tuesday, and even into
Tuesday evening, ending up dry. This dry slot is showing up nicely
as a nearly cloud free area over the central High Plains, although
we do not expect skies to be quite so clear by the time the drier
airmass arrives here. The initial upper/surface lows will dissipate
with time as a more vigorous wave rounds the base of the mean Plains
trof later Tuesday into Wednesday.
Our main snow concern arrives as the above mentioned wave heads
northeast, developing a new surface cyclone as it does so. While all
models still keep the track of the surface low east of the forecast
area, the track has shifted far enough west in most model solutions
that the deformation zone on its back side tracks across at least
east-central and southeast Illinois. However, a wide range of model
solutions exist in the timing, track, and precipitation intensity
within this deformation zone. It is also unclear if all the
precipitation within the deformation zone will fall as snow, or it
will fall as rain or a rain/snow mix for a time. Obviously, this is
critical to snow accumulation potential. While most guidance has
surface temperatures above freezing through Wednesday afternoon, the
"warm" air depth is very shallow, generally no more than 1000-1500
feet above the ground. If snowfall rates are high enough, they will
quickly be able to erode this warm layer. There are signs that
convective banding within the deformation zone is possible, which
would certainly provide high enough rates to support a quicker
change over to snow. In any event, due to the persistent
uncertainty, have gone with no more than an inch or two of snowfall
on the back side of the system, mainly east of I-55. If the latest
model trends hold, these totals will need to be boosted.
The next couple waves/precipitation threat have slowed a bit from
previous days, centering more on Saturday/Sunday than
Friday/Saturday time frame. Temperatures just ahead of the lead wave
support rain or a rain/snow mix, with conditions eventually cooling
enough for all snow. Precipitation amounts during this time appear
fairly minor for the moment.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1151 AM CST MON DEC 22 2014
Upper wave lifting northward from Oklahoma/Texas has spread low
clouds and rain across central Illinois late this morning. Area
surface obs indicate IFR ceilings across the board. Based on 12z
forecast soundings and latest HRRR output, think IFR conditions
will prevail through the afternoon and evening with off and on
rain showers. As the upper system lifts further northward, an
approaching mid-level dry slot will bring an end to the rain from
southwest to northeast across the area after later tonight. HRRR
suggests rain will end at KSPI by 08z, then further northeast to
KCMI by around 11z. Once rain ends, have raised ceilings to MVFR
late tonight into Tuesday morning. Winds will initially be from
the southeast at 10-15kt this afternoon/evening, then will become
southerly tonight. S/SW winds of 10-15kt will prevail by Tuesday
morning.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Bak
AVIATION...Barnes
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1229 PM CST MON DEC 22 2014
.SHORT TERM...
1227 PM CST
TONIGHT THROUGH CHRISTMAS DAY...
MAIN CHALLENGES FOR TONIGHT WILL BE ON PLACEMENT OF PRECIP ALONG
WITH HOW MUCH RAIN WILL FALL ACROSS THE FORECAST AREA. THE
NORTHERN STREAM SFC LOW HAS BECOME WRAPPED UP ACROSS THE
DAKOTAS...WITH THE MID-LVL TROUGH AXIS STRETCHING SOUTH THROUGH
THE SOUTHERN PLAINS. LLVL FLOW ACROSS THE FORECAST AREA HAS BECOME
MORE EASTERLY...WITH A FEED OF SOME SLIGHTLY DRIER AIR AT THE SFC
INTO NORTHERN IL/NORTHWEST IN. THIS HAS BEEN ABLE TO DELAY THE
ONSET OF STEADY PRECIP UNTIL LATER THIS AFTN. SFC TEMPS HAVE BEEN
SLOW TO WARM...AND LATEST GUIDANCE INDICATES THAT MAX TEMPS MAY
NOT OCCUR UNTIL JUST AFT 00Z AS A STEADY CONVEYOR OF WARMER/MOIST
AIR ADVECTS NORTH.
LOCAL SOLUTIONS BRING THE BETTER SLUG OF PRECIP INTO THE FORECAST
AREA THIS EVENING...THEN SLOWLY LIFT THE STEADIER RAIN NORTH
OVERNIGHT. QPF TOTALS HAVE DECREASED FROM EARLIER SOLUTIONS...BUT
HAVE ONLY MADE MINOR ADJUSTMENTS TO THE GOING FORECAST. THE SFC LOW
OVER THE DAKOTAS WILL BE SLIDING SOUTHEAST TOWARDS SOUTHEAST IOWA
OVERNIGHT...WITH A DRY WEDGE BECOMING ENTRAINED OVER MISSOURI.
GUIDANCE HAS BEEN LEANING TOWARDS POSSIBLY AN EARLIER ARRIVAL OF THE
DRY SLOT INTO THE FORECAST AREA JUST BEFORE DAYBREAK TUE. GIVEN THE
CONTINUED UNCERTAINTIES ON TRACK/PLACEMENT OF THE LOW...HAVE HELD
ONTO SOME LGT RAIN AT DAYBREAK THEN LIFT THE PRECIP SHIELD NORTH OF
INTO WISC BY MID-MORNING TUE. TEMPS OVERNIGHT MON SHUD BE NEARLY
STEADY...THEN AFT MIDNIGHT WITH A 850MB THERMAL RIDGE OF 3-6 DEG C
LIFTING NORTH EXPECT TEMPS TO BE SLOWLY RISING INTO THE LOW 40S.
TUE EXPECT THE SFC LOW TO BE SLOWLY WEAKENING ACROSS SOUTHWEST
WISC...WITH THE MID-LVL TROUGH AXIS EJECTING THE SECONDARY SFC LOW
ALONG THE WESTERN GULF. THIS SECONDARY LOW IS THE MAIN CONCERN FOR
WED AFTN-WED NGT ACROSS OUR REGION. THE DRY WEDGE SHUD KEEP PRECIP
WEST/NORTH OF THE FORECAST AREA THRU TUE MORNING...THEN WRAP AROUND
MOISTURE WILL BRING LGT RAIN BACK INTO THE AREA TUE AFTN/EVE. TEMPS
SHUD WARM INTO THE MID/UPR 40S...POSSIBLY TOUCHING 50 DEGREES IN THE
SOUTHEAST CWFA. THE SOUTHERN STREAM LOW WILL BE RAPIDLY DEEPENING
AND LIFTING NORTH ACROSS THE TENN VALLEY WED MORNING...THEN IT
BECOMES A CHALLENGE ON THE PLACEMENT OF THE LOW BEYOND WED MORNING.
GUIDANCE CONTINUES TO SHOW CORRECTIONS...WITH A FEW SOLUTIONS
BRINGING THE LOW NORTH INTO NORTHEAST IN AND A FEW FURTHER EAST.
THIS WILL BE A KEY PLAYER ON THE PLACEMENT OF THE POTENTIAL
DEFORMATION ZONE WHICH COULD BRING ACCUM SNOW TO THE FORECAST AREA
WED AFTN/EVE. TEMPS WILL BE FALLING DURING THE DAY WED...AND WITH
THE INCREASED FORCING...THIS COULD BR STRONG ENOUGH TO OVERCOME THE
WARMER AIR AT THE SFC AND ALLOW RAIN TO QUICKLY CHANGE TO SNOW AND
START ACCUMULATING. GEFS ENSEMBLES ARE BEGINNING TO DEMONSTRATE A
WEAK EASTERLY LLVL JET AT 850MB LIFTING NORTHEAST OVER THE FORECAST
AREA WED AFTN/EARLY EVE...WHICH WOULD SUPPORT THE IDEA OF A
DEFORMATION SNOW BAND FOR THE CENTRAL/EASTERN CWFA. CONSIDERABLE
UNCERTAINTY REMAINS WITH THIS SYSTEM...BUT EITHER WAY IT WILL IMPACT
A PORTION OF THE GREAT LAKES REGION ON ONE OF THE BUSIEST TRAVEL
DAYS OF THE YEAR.
FOR CHRISTMAS DAY...THE DOWNSTREAM RIDGE OVER THE CANADIAN MARITIME
WILL BEGIN TO WEAKEN AND ALLOW FOR THE 500MB TROUGH TO PUSH EAST OF
THE GREAT LAKES...LIFTING THE DEEPER MOISTURE/PRECIP NORTHEAST WITH
IT. MOST GUIDANCE COMES INTO SLIGHTLY BETTER AGREEMENT FOR HIGHS
ARND THE MID/UPR 30S...WITH POSSIBLY THINNING CLOUD COVER.
BEACHLER
&&
.LONG TERM...
314 AM CST
TUESDAY NIGHT THROUGH SUNDAY...
DURING THIS PERIOD THE PRIMARY FOCUS WILL BE WITH THE SECOND STORM
SYSTEM EXPECTED TO DEVELOP AND IMPACT THE GREAT LAKES REGION
CHRISTMAS EVE.
A VERY IMPRESSIVE JET CORE...IN EXCESS OF 150 KT...EXTENDS FROM THE
EASTERN PACIFIC...ONSHORE OVER THE NORTHWESTERN CONUS AT THIS
TIME. THIS JET MAX IS EXPECTED TO BE THE MAIN PLAYER IN THE
DEVELOPMENT OF A SIGNIFICANT STORM SYSTEM BY MID WEEK. MODEL
SOLUTIONS (NAM ASIDE) HAVE COME INTO SOME BETTER AGREEMENT WITH THE
SURFACE LOW. OVERALL...IT APPEARS THAT CYCLOGENESIS WILL BE INDUCED
NEAR THE CENTRAL GULF COAST BY LATE TUESDAY...THEN RACE NORTHWARD
ACROSS THE OHIO VALLEY REGION AND INTO THE CENTRAL GREAT LAKES
REGION BY CHRISTMAS EVE NIGHT. IT STILL APPEARS THAT THE SURFACE LOW
WILL DEEPEN CONSIDERABLY LATE WEDNESDAY AND INTO CHRISTMAS MORNING
AS THE UPPER LEVEL IMPULSE LOOKS TO TAKE ON A NEGATIVE TILT. MOST
OPERATIONAL GUIDANCE HINTS AT HEALTHY 15 TO 20 MB DEEPENING BETWEEN
12 UTC WEDNESDAY AND 12 UTC THURSDAY.
ALTHOUGH TWEAKS TO THE TRACK AND TIMING OF THE SYSTEM ARE STILL A
POSSIBILITY...IT APPEARS THE MAIN UNCERTAINTIES AT THIS POINT WILL BE
THE MESOSCALE DETAILS...AND HENCE WHERE THE BEST DEFORMATION BANDING
WILL OCCUR LATER IN THE DAY CHRISTMAS EVE. BOTH THE GFS AND THE
PAR GFS INDICATE A SLIGHTLY FARTHER NORTH PROGRESSION OF THE
DEFORMATION BAND ACROSS MUSH OF NORTHEASTERN ILLINOIS AND
NORTHWESTERN INDIAN WED AFTERNOON AND EVENING. IN CONTRAST THE
ECMWF...GEM AND UKMET ARE A BIT FARTHER SOUTH...MAINLY IMPACTING MY
SOUTHEASTERN CWA. OVERALL...THERE IS TYPICALLY A STRONG NORTHWESTERN
GRADIENT TO THESE DEFORMATION BANDS...SO THIS COULD LEAD TO A SHARP
CONTRAST IN PRECIPITATION AMOUNTS ACROSS MY CWA.
IT APPEARS THAT PRECIPITATION TYPE WITHIN THIS DEFORMATION BAND WOULD
LIKELY BE IN THE FORM OF SNOW. MODEL SOUNDINGS SUGGEST THAT
BOUNDARY LAYER TEMPERATURES MAY REMAIN A BIT WARM LATE WEDNESDAY AND
EVENING...BUT TYPICALLY DYNAMIC COOLING FROM STRONG FORCING FOR
ASCENT WITHIN THESE DEFORMATION BANDS LEADS TO TRANSITION TO A
PERIOD OF MODERATE TO EVEN HEAVY SNOWFALL. AT THE CURRENT TIME...I
HAVE REMAINED VERY CONSERVATIVE ON SNOW AMOUNTS OVER THE AREA...DUE
TO UNCERTAINTIES ON WHERE THIS POTENTIAL BAND OF HEAVIER PRECIP SETS UP.
HOWEVER...I WOULD NOT BE SURPRISED FOR SOME AREAS...PARTICULARLY IN MY
SOUTHERN AND EASTERN CWA TO END UP WITH SEVERAL INCHES OF
SNOW BY LATE CHRISTMAS EVE. AS SUCH...CHANGES TO SNOW AMOUNTS IS A
GOOD LIKELIHOOD.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CIGS LOWERING TO IFR/LIFR THIS AFTERNOON EVENING.
* PERIODS OF RAIN THROUGH TONIGHT
* REDUCED VSBY AT TIMES 1-3 SM.
BMD
//DISCUSSION...UPDATED 18Z...
CONDITIONS ARE STEADILY DETERIORATING ALREADY WITH THE 18Z TAF
ISSUANCE AND EXPECT THIS TREND TO CONTINUE THROUGH THE AFTERNOON
HOURS. A LEAD UPPER LEVEL DISTURBANCE HAS ALLOWED RAIN TO OVERSPREAD
THE TERMINALS LATE THIS MORNING. A FEW SITES HAVE REPORTED A FEW ICE
PELLETS BUT SOUNDINGS INDICATE THE COLUMN WILL QUICKLY WARM AND WILL
NO LONGER SUPPORT FROZEN PRECIPITATION THROUGH THE REMAINDER OF THE
TAF PERIOD. CIGS ARE EXPECTED TO FAIRLY QUICKLY DROP TO IFR EARLY TO
MID AFTERNOON TODAY AND WILL REMAIN THERE OVERNIGHT. BEHIND THE LEAD
WAVE...THERE MAY BE A LULL IN THE PRECIP INTENSITY BUT MOIST
CONDITIONS AND SOME FORCING MAY RESULT IN A VERY LIGHT RAIN OR
DRIZZLE CONTINUING OVERNIGHT. THE MAIN UPPER WAVE AND WARM FRONT WILL
LIFT ACROSS THE REGION EARLY TUESDAY RESULTING IN PRECIP INTENSITY
INCREASING ONCE AGAIN. ONCE THE WARM FRONT LIFTS NORTH OF THE
TERMINALS...PRECIP SHOULD TAPER AND THERE MAY BE A GRADUAL RISE IN
CIG HEIGHTS BACK INTO MVFR.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN ANY MIXED PRECIP CHANGING OVER TO ALL RAIN
WITHIN NEXT HOUR.
* HIGH CONFIDENCE IN GENERAL CIG TRENDS BUT LOW-MEDIUM CONFIDENCE
IN TIMING.
* LOW CONFIDENCE IN VSBY TRENDS THIS EVENING AND TONIGHT.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...DRY. MAINLY VFR...THOUGH MVFR POSSIBLE LATE.
WEDNESDAY...CHANCE OF RA/SN CHANGING TO SN. IFR LIKELY.
THURSDAY...CHANCE OF MVFR CIGS...MAINLY EARLY.
FRIDAY...CHANCE OF MVFR CIGS. CHANCE OF -RA/-SN
SATURDAY AND SUNDAY...MAINLY VFR.
RATZER
&&
.MARINE...
233 AM CST
FORECAST FOR LAKE MICHIGAN REMAINS COMPLICATED THIS MORNING...WITH
TWO AREAS OF LOW PRESSURE EXPECTED TO BRING PERIODS OF STRONG WINDS
ACROSS THE LAKE OVER THE NEXT SEVERAL DAYS.
THE FIRST LOW WAS MOVING SOUTHEAST ACROSS THE DAKOTAS EARLY THIS
MORNING...WITH A TIGHTENING PRESSURE GRADIENT EXTENDING EAST INTO
THE WESTERN LAKES. OBSERVATION PLATFORMS ALONG THE WEST AND
NORTHWEST SHORES OF THE LAKE WERE REPORTING SOUTH WINDS IN THE 25-30
KT RANGE...WITH WINDS TO 30 KT EXPECTED TO BACK TO THE EAST AS THE
LOW MOVES TO THE IOWA-MISSOURI BORDER TONIGHT. THE LOW WILL THEN
BEGIN TO FILL AS IT TURNS NORTHEAST...LIFTING ACROSS NORTHERN LAKE
MICHIGAN LATE TUESDAY.
EXPECTATIONS ARE THAT A SECOND LOW WILL DEVELOP TO THE SOUTH ACROSS
THE TENNESSEE AND OHIO RIVER VALLEYS BY EARLY WEDNESDAY MORNING...
DEEPENING AS IT LIFTS NORTHWARD INTO THE CENTRAL GREAT LAKES REGION
BY WEDNESDAY EVENING. MODELS CONTINUE TO SHOW DIFFERENCES IN THE
EXACT TRACK AND STRENGTH OF THE LOW AS IT PASSES EAST OF LAKE
MICHIGAN...AS WELL AS NORTH AND NORTHWEST WIND SPEEDS WEDNESDAY
AFTERNOON INTO THURSDAY MORNING. AT THIS POINT...IT APPEARS THAT
WINDS OF 25-30 KT ARE LIKELY...AND POSSIBLY STILL GALES FOR A TIME
IF THE LOW DEEPENS A LITTLE FASTER. WINDS THEN LOOK TO DIMINISH AND
BACK TO THE WEST AND THEN SOUTHWEST CHRISTMAS DAY. MODELS ARE IN
BETTER AGREEMENT IN ANOTHER LOW APPROACHING AND LIFTING ACROSS THE
NORTHERN LAKES FRIDAY AND FRIDAY NIGHT.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM TUESDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1151 AM CST Mon Dec 22 2014
.UPDATE...
ISSUED AT 904 AM CST MON DEC 22 2014
Made a quick update to the forecast to increase PoPs to 100
percent as light rain has already spread across much of the KILX
CWA. The exceptions are northwest of the Illinois River and
further east near the Indiana border. Based on radar trends and
latest HRRR and NAM forecasts, light rain will spread across the
remainder of the area over the next couple of hours. May see a
brief period of a rain/sleet mix northeast of I-74 near Rantoul
and Danville as the precip initially begins, but it will quickly
transition to all rain. Also made a few tweaks to hourly temps and
lowered afternoon highs by a couple of degrees due to rain and a
continued E/SE flow. Highs will reach the lower to middle 40s.
&&
.SHORT TERM...(Today)
ISSUED AT 501 AM CST MON DEC 22 2014
Strong jet (175kts) over the Pacific Northwest digging southeast
into a deepening central Plains trof this morning will eject an
initial wave into our area today bringing rain along with mild
temperatures. Low pressure is expected to consolidate over north
central Missouri by late this afternoon and then track thru
northwest Illinois early this evening. The southerly flow in advance
of the storm system will quickly saturate the lower levels of the
atmosphere with rain overspreading the area from southwest to
northeast this morning. Some weak isentropic lift and moisture
convergence early this morning has produced some spotty light
rain/drizzle over parts of central Illinois and expect that to
continue before the stronger forcing arrives later this morning.
Models suggest the strongest lift moves into our area from mid
morning thru the early evening hours, so high POPs are warranted
over most of the forecast area today. Despite the cloud cover and
precip, mild temperatures to prevail again today with afternoon
readings in the mid to upper 40s.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 501 AM CST MON DEC 22 2014
Increased rain chances to categorical this evening with supporting
lift of low level jet and short waves ejecting ne from
central/southern plains into IL tonight. Rain chances to diminish
from sw to ne during overnight into Tue morning as energy shifts
north of central IL Tue. Appears to be a lull in rain chances Tue
and Tue evening over much of central IL with best rain chances
shifting to our north with surface low pressure over southern WI Tue
afternoon and also to our se. Mild lows tonight of 40-45F and highs
Tue range from mid 40s over IL river valley and lower 50s in
southeast IL.
00Z models still not in good agreement with development of strong
low pressure system from northwestern Gulf of Mexico and deepening
nne across the ohio river valley Wed. NAM model appears is dry over
IL Tue night and Wed but feel its low pressure track is too far east
near the foothills of the Appalachians. Will use a blend of the
ECMWF/GEM and GFS models for the storm system during midweek. Have
precipitation chances spreading back northward across central IL
overnight Tue night into Wed and diminishing from west to east by
overnight Wed night. Warm enough for rain Tue evening, then mixing
with and gradually changing to light snow later Tue night into Wed
from west to east. Deformation band of light snow accumulations
likely to set up on back side of storm system, though placement of
this band is still too difficult to pinpoint down. WPC keeps snow
accumulations less than 1 inch over central/eastern IL on
Wed/Christmas eve. Cooler highs Wed in the upper 30s to near 40F
eastern IL and will likely slip during the afternoon with increasing
WNW winds.
Christmas Day still looks dry with return of some sunshine as strong
storm system lifts into Quebec and 1025 mb surface high pressure
over gulf of mexico ridges northward into the ohio river valley.
Highs in the lower 40s Thu/Christmas Day, so any snow that does fall
Wed will likely melt.
Models have another low pressure taking a track more nw of central
IL Friday and lifting into the western Great Lakes Friday night.
Have small chances of light precipitation Fri/Fri night and then dry
for the weekend. Models showing yet another southern low pressure
system over gulf of Mexico Sat night/Sunday but for now will keep
precipitation chances south of central IL.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1151 AM CST MON DEC 22 2014
Upper wave lifting northward from Oklahoma/Texas has spread low
clouds and rain across central Illinois late this morning. Area
surface obs indicate IFR ceilings across the board. Based on 12z
forecast soundings and latest HRRR output, think IFR conditions
will prevail through the afternoon and evening with off and on
rain showers. As the upper system lifts further northward, an
approaching mid-level dry slot will bring an end to the rain from
southwest to northeast across the area after later tonight. HRRR
suggests rain will end at KSPI by 08z, then further northeast to
KCMI by around 11z. Once rain ends, have raised ceilings to MVFR
late tonight into Tuesday morning. Winds will initially be from
the southeast at 10-15kt this afternoon/evening, then will become
southerly tonight. S/SW winds of 10-15kt will prevail by Tuesday
morning.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barnes
SHORT TERM...Smith
LONG TERM...07
AVIATION...Barnes
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1013 AM CST MON DEC 22 2014
.SHORT TERM...
314 AM CST
TODAY THROUGH TUESDAY...
THE MAIN CONCERNS DURING THIS PERIOD CONTINUE TO BE FOCUSED ON
RAINFALL AMOUNTS AND TIMING.
WATER VAPOR IMAGERY EARLY THIS MORNING INDICATES SEVERAL SMALLER
SCALE MID LEVEL VORT IMPULSES MOVING WITHIN THE LARGER SCALE TROUGH
ENCOMPASSING MUCH OF THE CENTRAL CONUS FROM THE ROCKIES EASTWARD TO
THE MISSISSIPPI VALLEY. ONE SUCH IMPULSE IS CURRENT SHIFTING ACROSS
THE AREA...AND THIS HAS ACTED TO SPARK OFF SOME LIGHT PRECIPITATION
ACROSS PORTIONS OF THE AREA OVER THE PAST COUPLE HOURS. MOST SURFACE
OBSERVATIONS UNDER THE RADAR ECHOS HAVE REPORTED RAIN OR DRIZZLE.
HOWEVER...WITH SURFACE TEMPERATURES HOVERING RIGHT AT FREEZING
ACROSS MUCH OF NORTHERN ILLINOIS...SOME AREAS COULD BE EXPERIENCING
SOME MINOR GLAZING. THIS INITIAL DISTURBANCE SHOULD MOVE NORTHEAST
OF THE AREA BY DAYBREAK...SO THERE WILL LIKELY BE A LULL IN THE
PRECIPITATION FOR SEVERAL HOURS THIS MORNING AFTER AROUND
DAYBREAK...THROUGH MID TO LATE MORNING. THEREAFTER...A SECOND MID
LEVEL IMPULSE...CURRENTLY NOTED ACROSS EASTERN PORTIONS OF
OKLAHOMA...WILL SHIFT NORTH-NORTHEASTWARD TOWARDS THE AREA BY THIS
AFTERNOON.
THIS SECOND DISTURBANCE WILL BE ACCOMPANIED BY A BETTER INFLUX OF
MOISTURE...ALLOWING FOR MORE WIDESPREAD RAIN DEVELOPMENT ACROSS
CENTRAL PORTIONS OF ILLINOIS AND INDIANA BY LATE MORNING...BEFORE
SHIFTING NORTHWARD ALL OF NORTHERN ILLINOIS/NORTHWESTERN INDIANA BY
EARLY THIS AFTERNOON. THEREFORE...A VERY WET AFTERNOON IS IN STORE
FOR THE AREA. IT IS STILL POSSIBILITY THAT AS THIS BACH OF PRECIPITATION
BEGINS TO ENTER FAR NORTHERN SECTIONS OF ILLINOIS LATER THIS
MORNING...THAT IT COULD ONSET AS A MIX OF SLEET...SNOW AND RAIN.
MODEL SOUNDINGS INDICATE PROFILES SPORTIVE OF SUCH FOR A SMALL WINDOW
OF TIME THROUGH AROUND MIDDAY. A SURGE OF A WARMER AND MOIST AIRMASS
WILL END THIS BY EARLY AFTERNOON AS ALL RAIN WILL BE FAVORED
AREA-WIDE.
AS WE HEAD INTO THE EVENING ANOTHER BACH OF RAINFALL IS EXPECTED TO
DEVELOP NORTHWARD ACROSS THE AREA. THIS ADDITIONAL RAINFALL WILL BE
DRIVEN BY YET ANOTHER INFLUX OF AN EVEN WARMER MORE MOIST AIRMASS
OUT AHEAD OF A CLOSING OFF MID LEVEL CIRCULATION OVER THE MID
MISSOURI VALLEY. THIS PROCESS WILL ALSO DRIVE ADDITIONAL MID LEVEL
IMPULSES NORTHEASTWARD ALONG ITS SOUTHEASTERN PERIPHERY RIGHT ACROSS
THE AREA. AT THE SURFACE...LOW PRESSURE WILL SHIFT FROM THE NORTHERN
PLAINS TO THE IOWA...MISSOURI STATE LINE BY THIS EVENING...THEN LIFT
A WARM/OCCLUDED FRONTAL BOUNDARY NORTHWARD ACROSS THE AREA BY
DAYBREAK TUESDAY. ONCE THIS FRONTAL BOUNDARY LIFTS OVER THE
AREA...AN ACCOMPANYING MID LEVEL DRY SLOT IS EXPECTED TO SHIFT OVER
THE AREA...BRINGING AN END TO MUCH OF THE RAINFALL EITHER VERY LATE
TONIGHT OR EARLY TUESDAY MORNING. THEREFORE...MUCH OF THE DAY
TUESDAY LOOKS TO BE CLOUDY...MILD AND ASIDE FROM THE POSSIBILITY FOR
SOME LINGERING DRIZZLE...MAINLY DRY.
TOTAL RAINFALL AMOUNTS WITH THIS ACTIVITY THIS AFTERNOON INTO
TONIGHT COULD RANGE BETWEEN A HALF INCH AND ONE INCH...AS SOME
PERIODS OF MODERATE RAIN ARE POSSIBLE INTO THIS EVENING AS PWATS
CREEP UP IN EXCESS OF 3/4 OF AN INCH. I HAVE ATTEMPTED TO FOCUS THE
BEST CHANCES FOR RAINFALL FROM MID TO LATE MORNING THROUGH LATER
TONIGHT ACROSS MY CENTRAL ILLINOIS COUNTIES...AND FROM AROUND MIDDAY
THROUGH TONIGHT FOR MY NORTHERN AREAS.
KJB
&&
.LONG TERM...
314 AM CST
TUESDAY NIGHT THROUGH SUNDAY...
DURING THIS PERIOD THE PRIMARY FOCUS WILL BE WITH THE SECOND STORM
SYSTEM EXPECTED TO DEVELOP AND IMPACT THE GREAT LAKES REGION
CHRISTMAS EVE.
A VERY IMPRESSIVE JET CORE...IN EXCESS OF 150 KT...EXTENDS FROM THE
EASTERN PACIFIC...ONSHORE OVER THE NORTHWESTERN CONUS AT THIS
TIME. THIS JET MAX IS EXPECTED TO BE THE MAIN PLAYER IN THE
DEVELOPMENT OF A SIGNIFICANT STORM SYSTEM BY MID WEEK. MODEL
SOLUTIONS (NAM ASIDE) HAVE COME INTO SOME BETTER AGREEMENT WITH THE
SURFACE LOW. OVERALL...IT APPEARS THAT CYCLOGENESIS WILL BE INDUCED
NEAR THE CENTRAL GULF COAST BY LATE TUESDAY...THEN RACE NORTHWARD
ACROSS THE OHIO VALLEY REGION AND INTO THE CENTRAL GREAT LAKES
REGION BY CHRISTMAS EVE NIGHT. IT STILL APPEARS THAT THE SURFACE LOW
WILL DEEPEN CONSIDERABLY LATE WEDNESDAY AND INTO CHRISTMAS MORNING
AS THE UPPER LEVEL IMPULSE LOOKS TO TAKE ON A NEGATIVE TILT. MOST
OPERATIONAL GUIDANCE HINTS AT HEALTHY 15 TO 20 MB DEEPENING BETWEEN
12 UTC WEDNESDAY AND 12 UTC THURSDAY.
ALTHOUGH TWEAKS TO THE TRACK AND TIMING OF THE SYSTEM ARE STILL A
POSSIBILITY...IT APPEARS THE MAIN UNCERTAINTIES AT THIS POINT WILL BE
THE MESOSCALE DETAILS...AND HENCE WHERE THE BEST DEFORMATION BANDING
WILL OCCUR LATER IN THE DAY CHRISTMAS EVE. BOTH THE GFS AND THE
PAR GFS INDICATE A SLIGHTLY FARTHER NORTH PROGRESSION OF THE
DEFORMATION BAND ACROSS MUSH OF NORTHEASTERN ILLINOIS AND
NORTHWESTERN INDIAN WED AFTERNOON AND EVENING. IN CONTRAST THE
ECMWF...GEM AND UKMET ARE A BIT FARTHER SOUTH...MAINLY IMPACTING MY
SOUTHEASTERN CWA. OVERALL...THERE IS TYPICALLY A STRONG NORTHWESTERN
GRADIENT TO THESE DEFORMATION BANDS...SO THIS COULD LEAD TO A SHARP
CONTRAST IN PRECIPITATION AMOUNTS ACROSS MY CWA.
IT APPEARS THAT PRECIPITATION TYPE WITHIN THIS DEFORMATION BAND WOULD
LIKELY BE IN THE FORM OF SNOW. MODEL SOUNDINGS SUGGEST THAT
BOUNDARY LAYER TEMPERATURES MAY REMAIN A BIT WARM LATE WEDNESDAY AND
EVENING...BUT TYPICALLY DYNAMIC COOLING FROM STRONG FORCING FOR
ASCENT WITHIN THESE DEFORMATION BANDS LEADS TO TRANSITION TO A
PERIOD OF MODERATE TO EVEN HEAVY SNOWFALL. AT THE CURRENT TIME...I
HAVE REMAINED VERY CONSERVATIVE ON SNOW AMOUNTS OVER THE AREA...DUE
TO UNCERTAINTIES ON WHERE THIS POTENTIAL BAND OF HEAVIER PRECIP SETS UP.
HOWEVER...I WOULD NOT BE SURPRISED FOR SOME AREAS...PARTICULARLY IN MY
SOUTHERN AND EASTERN CWA TO END UP WITH SEVERAL INCHES OF
SNOW BY LATE CHRISTMAS EVE. AS SUCH...CHANGES TO SNOW AMOUNTS IS A
GOOD LIKELIHOOD.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* VFR LOWERING TO IFR AND POSSIBLY LIFR THIS EVENING.
* RAIN DEVELOPING OVER NEXT COUPLE HOURS CONTINUING INTO TONIGHT.
* SOUTHEAST WINDS AROUND 10 KT BECOMING EAST-SOUTHEAST 10-15 KT
BY AFTERNOON.
RATZER/DEUBELBEISS
//DISCUSSION...UPDATED 12Z...
LOW PRESSURE MOVING SOUTHEAST FROM THE DAKOTAS TO THE MIDWEST
TODAY...WITH RAIN AND LOW CIGS/VSBY EXPECTED TO DEVELOP FROM THE
SOUTHWEST BY MIDDAY/EARLY AFTERNOON AS MOISTURE SPREADS INTO THE
REGION AHEAD OF THE LOW. SOME SPOTTY LIGHT PRECIP MAINLY WEST AND
NORTHWEST OF CHICAGO TERMINALS EARLY THIS MORNING...WITH MARGINAL
THERMAL PROFILES SUPPORTING LIGHT RAIN/LIGHT SNOW/LIGHT SLEET.
PRECIPITATION TO BECOME ALL RAIN BY AFTERNOON WITH TEMPS RISING
WELL ABOVE FREEZING. RAIN CONTINUES INTO TONIGHT AND TAPERS TO
DRIZZLE AT TIMES OVERNIGHT.
VFR CIGS WITH SOME MVFR VSBY IN HAZE EARLY THIS MORNING...WITH
CIGS/VSBY EXPECTED TO DETERIORATE TO IFR THIS AFTERNOON AFTER RAIN
DEVELOPS AND LIKELY TO LIFR OVERNIGHT. SOME IMPROVEMENT EXPECTED
TUESDAY MORNING AS WARM FRONT LIFTS NORTH OF TERMINALS.
SOUTHEAST WINDS NEAR 10 KT THIS MORNING TO BECOME EAST-SOUTHEAST
TODAY AND TONIGHT 10-15 KTS. WINDS TURN BACK TO THE SOUTH AND
EVENTUALLY SOUTHWEST TUESDAY MORNING WITH WARM FRONT PASSAGE.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM IN CIGS THROUGH PERIOD...THOUGH MEDIUM LOW IN TIMING
SHIFT TO IFR AND LIFR.
* MEDIUM-HIGH IN GENERAL PRECIP TIMING AND WIND TRENDS.
RATZER/DEUBELBEISS
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...DRY. MAINLY VFR...THOUGH MVFR POSSIBLE LATE.
WEDNESDAY...CHANCE OF RA/SN CHANGING TO SN. IFR LIKELY.
THURSDAY...CHANCE OF MVFR CIGS...MAINLY EARLY.
FRIDAY...CHANCE OF MVFR CIGS. CHANCE OF -RA/-SN
SATURDAY AND SUNDAY...MAINLY VFR.
RATZER
&&
.MARINE...
233 AM CST
FORECAST FOR LAKE MICHIGAN REMAINS COMPLICATED THIS MORNING...WITH
TWO AREAS OF LOW PRESSURE EXPECTED TO BRING PERIODS OF STRONG WINDS
ACROSS THE LAKE OVER THE NEXT SEVERAL DAYS.
THE FIRST LOW WAS MOVING SOUTHEAST ACROSS THE DAKOTAS EARLY THIS
MORNING...WITH A TIGHTENING PRESSURE GRADIENT EXTENDING EAST INTO
THE WESTERN LAKES. OBSERVATION PLATFORMS ALONG THE WEST AND
NORTHWEST SHORES OF THE LAKE WERE REPORTING SOUTH WINDS IN THE 25-30
KT RANGE...WITH WINDS TO 30 KT EXPECTED TO BACK TO THE EAST AS THE
LOW MOVES TO THE IOWA-MISSOURI BORDER TONIGHT. THE LOW WILL THEN
BEGIN TO FILL AS IT TURNS NORTHEAST...LIFTING ACROSS NORTHERN LAKE
MICHIGAN LATE TUESDAY.
EXPECTATIONS ARE THAT A SECOND LOW WILL DEVELOP TO THE SOUTH ACROSS
THE TENNESSEE AND OHIO RIVER VALLEYS BY EARLY WEDNESDAY MORNING...
DEEPENING AS IT LIFTS NORTHWARD INTO THE CENTRAL GREAT LAKES REGION
BY WEDNESDAY EVENING. MODELS CONTINUE TO SHOW DIFFERENCES IN THE
EXACT TRACK AND STRENGTH OF THE LOW AS IT PASSES EAST OF LAKE
MICHIGAN...AS WELL AS NORTH AND NORTHWEST WIND SPEEDS WEDNESDAY
AFTERNOON INTO THURSDAY MORNING. AT THIS POINT...IT APPEARS THAT
WINDS OF 25-30 KT ARE LIKELY...AND POSSIBLY STILL GALES FOR A TIME
IF THE LOW DEEPENS A LITTLE FASTER. WINDS THEN LOOK TO DIMINISH AND
BACK TO THE WEST AND THEN SOUTHWEST CHRISTMAS DAY. MODELS ARE IN
BETTER AGREEMENT IN ANOTHER LOW APPROACHING AND LIFTING ACROSS THE
NORTHERN LAKES FRIDAY AND FRIDAY NIGHT.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP TO WILMETTE HARBORS UNTIL 9 AM TUESDAY.
SMALL CRAFT ADVISORY...LMZ741-LMZ742 UNTIL 9 AM TUESDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
904 AM CST Mon Dec 22 2014
.UPDATE...
ISSUED AT 904 AM CST MON DEC 22 2014
Made a quick update to the forecast to increase PoPs to 100
percent as light rain has already spread across much of the KILX
CWA. The exceptions are northwest of the Illinois River and
further east near the Indiana border. Based on radar trends and
latest HRRR and NAM forecasts, light rain will spread across the
remainder of the area over the next couple of hours. May see a
brief period of a rain/sleet mix northeast of I-74 near Rantoul
and Danville as the precip initially begins, but it will quickly
transition to all rain. Also made a few tweaks to hourly temps and
lowered afternoon highs by a couple of degrees due to rain and a
continued E/SE flow. Highs will reach the lower to middle 40s.
&&
.SHORT TERM...(Today)
ISSUED AT 501 AM CST MON DEC 22 2014
Strong jet (175kts) over the Pacific Northwest digging southeast
into a deepening central Plains trof this morning will eject an
initial wave into our area today bringing rain along with mild
temperatures. Low pressure is expected to consolidate over north
central Missouri by late this afternoon and then track thru
northwest Illinois early this evening. The southerly flow in advance
of the storm system will quickly saturate the lower levels of the
atmosphere with rain overspreading the area from southwest to
northeast this morning. Some weak isentropic lift and moisture
convergence early this morning has produced some spotty light
rain/drizzle over parts of central Illinois and expect that to
continue before the stronger forcing arrives later this morning.
Models suggest the strongest lift moves into our area from mid
morning thru the early evening hours, so high POPs are warranted
over most of the forecast area today. Despite the cloud cover and
precip, mild temperatures to prevail again today with afternoon
readings in the mid to upper 40s.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 501 AM CST MON DEC 22 2014
Increased rain chances to categorical this evening with supporting
lift of low level jet and short waves ejecting ne from
central/southern plains into IL tonight. Rain chances to diminish
from sw to ne during overnight into Tue morning as energy shifts
north of central IL Tue. Appears to be a lull in rain chances Tue
and Tue evening over much of central IL with best rain chances
shifting to our north with surface low pressure over southern WI Tue
afternoon and also to our se. Mild lows tonight of 40-45F and highs
Tue range from mid 40s over IL river valley and lower 50s in
southeast IL.
00Z models still not in good agreement with development of strong
low pressure system from northwestern Gulf of Mexico and deepening
nne across the ohio river valley Wed. NAM model appears is dry over
IL Tue night and Wed but feel its low pressure track is too far east
near the foothills of the Appalachians. Will use a blend of the
ECMWF/GEM and GFS models for the storm system during midweek. Have
precipitation chances spreading back northward across central IL
overnight Tue night into Wed and diminishing from west to east by
overnight Wed night. Warm enough for rain Tue evening, then mixing
with and gradually changing to light snow later Tue night into Wed
from west to east. Deformation band of light snow accumulations
likely to set up on back side of storm system, though placement of
this band is still too difficult to pinpoint down. WPC keeps snow
accumulations less than 1 inch over central/eastern IL on
Wed/Christmas eve. Cooler highs Wed in the upper 30s to near 40F
eastern IL and will likely slip during the afternoon with increasing
WNW winds.
Christmas Day still looks dry with return of some sunshine as strong
storm system lifts into Quebec and 1025 mb surface high pressure
over gulf of mexico ridges northward into the ohio river valley.
Highs in the lower 40s Thu/Christmas Day, so any snow that does fall
Wed will likely melt.
Models have another low pressure taking a track more nw of central
IL Friday and lifting into the western Great Lakes Friday night.
Have small chances of light precipitation Fri/Fri night and then dry
for the weekend. Models showing yet another southern low pressure
system over gulf of Mexico Sat night/Sunday but for now will keep
precipitation chances south of central IL.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 515 AM CST MON DEC 22 2014
Deteriorating conditions expected across the area this morning
as a storm system tracks into the region. Mostly VFR cigs being
reported early this morning but expect those to transition to
MVFR and then IFR from south to north after 15z this morning as
rain increases in coverage over our area. We expect IFR to LIFR
conditions this afternoon into tonight as the rain continues on
and off thru 00z. In the 03z-06z, the rain is expected to taper
off with a lull in the precip after 06z as the storm system shifts
north of our area overnight. Surface winds will be east to southeast
today at 10 to 15 kts with a few gusts around 20 kts later this
morning into the afternoon hours. Southeast winds of 10 to 15 kts
can be expected tonight.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barnes
SHORT TERM...Smith
LONG TERM...07
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
316 AM CST MON DEC 22 2014
...SHORT TERM...TODAY THROUGH TUESDAY
314 AM CST
THE MAIN CONCERNS DURING THIS PERIOD CONTINUE TO BE FOCUSED ON
RAINFALL AMOUNTS AND TIMING.
WATER VAPOR IMAGERY EARLY THIS MORNING INDICATES SEVERAL SMALLER
SCALE MID LEVEL VORT IMPULSES MOVING WITHIN THE LARGER SCALE TROUGH
ENCOMPASSING MUCH OF THE CENTRAL CONUS FROM THE ROCKIES EASTWARD TO
THE MISSISSIPPI VALLEY. ONE SUCH IMPULSE IS CURRENT SHIFTING ACROSS
THE AREA...AND THIS HAS ACTED TO SPARK OFF SOME LIGHT PRECIPITATION
ACROSS PORTIONS OF THE AREA OVER THE PAST COUPLE HOURS. MOST SURFACE
OBSERVATIONS UNDER THE RADAR ECHOS HAVE REPORTED RAIN OR DRIZZLE.
HOWEVER...WITH SURFACE TEMPERATURES HOVERING RIGHT AT FREEZING
ACROSS MUCH OF NORTHERN ILLINOIS...SOME AREAS COULD BE EXPERIENCING
SOME MINOR GLAZING. THIS INITIAL DISTURBANCE SHOULD MOVE NORTHEAST
OF THE AREA BY DAYBREAK...SO THERE WILL LIKELY BE A LULL IN THE
PRECIPITATION FOR SEVERAL HOURS THIS MORNING AFTER AROUND
DAYBREAK...THROUGH MID TO LATE MORNING. THEREAFTER...A SECOND MID
LEVEL IMPULSE...CURRENTLY NOTED ACROSS EASTERN PORTIONS OF
OKLAHOMA...WILL SHIFT NORTH-NORTHEASTWARD TOWARDS THE AREA BY THIS
AFTERNOON.
THIS SECOND DISTURBANCE WILL BE ACCOMPANIED BY A BETTER INFLUX OF
MOISTURE...ALLOWING FOR MORE WIDESPREAD RAIN DEVELOPMENT ACROSS
CENTRAL PORTIONS OF ILLINOIS AND INDIANA BY LATE MORNING...BEFORE
SHIFTING NORTHWARD ALL OF NORTHERN ILLINOIS/NORTHWESTERN INDIANA BY
EARLY THIS AFTERNOON. THEREFORE...A VERY WET AFTERNOON IS IN STORE
FOR THE AREA. IT IS STILL POSSIBILITY THAT AS THIS BACH OF PRECIPITATION
BEGINS TO ENTER FAR NORTHERN SECTIONS OF ILLINOIS LATER THIS
MORNING...THAT IT COULD ONSET AS A MIX OF SLEET...SNOW AND RAIN.
MODEL SOUNDINGS INDICATE PROFILES SPORTIVE OF SUCH FOR A SMALL WINDOW
OF TIME THROUGH AROUND MIDDAY. A SURGE OF A WARMER AND MOIST AIRMASS
WILL END THIS BY EARLY AFTERNOON AS ALL RAIN WILL BE FAVORED
AREA-WIDE.
AS WE HEAD INTO THE EVENING ANOTHER BACH OF RAINFALL IS EXPECTED TO
DEVELOP NORTHWARD ACROSS THE AREA. THIS ADDITIONAL RAINFALL WILL BE
DRIVEN BY YET ANOTHER INFLUX OF AN EVEN WARMER MORE MOIST AIRMASS
OUT AHEAD OF A CLOSING OFF MID LEVEL CIRCULATION OVER THE MID
MISSOURI VALLEY. THIS PROCESS WILL ALSO DRIVE ADDITIONAL MID LEVEL
IMPULSES NORTHEASTWARD ALONG ITS SOUTHEASTERN PERIPHERY RIGHT ACROSS
THE AREA. AT THE SURFACE...LOW PRESSURE WILL SHIFT FROM THE NORTHERN
PLAINS TO THE IOWA...MISSOURI STATE LINE BY THIS EVENING...THEN LIFT
A WARM/OCCLUDED FRONTAL BOUNDARY NORTHWARD ACROSS THE AREA BY
DAYBREAK TUESDAY. ONCE THIS FRONTAL BOUNDARY LIFTS OVER THE
AREA...AN ACCOMPANYING MID LEVEL DRY SLOT IS EXPECTED TO SHIFT OVER
THE AREA...BRINGING AN END TO MUCH OF THE RAINFALL EITHER VERY LATE
TONIGHT OR EARLY TUESDAY MORNING. THEREFORE...MUCH OF THE DAY
TUESDAY LOOKS TO BE CLOUDY...MILD AND ASIDE FROM THE POSSIBILITY FOR
SOME LINGERING DRIZZLE...MAINLY DRY.
TOTAL RAINFALL AMOUNTS WITH THIS ACTIVITY THIS AFTERNOON INTO
TONIGHT COULD RANGE BETWEEN A HALF INCH AND ONE INCH...AS SOME
PERIODS OF MODERATE RAIN ARE POSSIBLE INTO THIS EVENING AS PWATS
CREEP UP IN EXCESS OF 3/4 OF AN INCH. I HAVE ATTEMPTED TO FOCUS THE
BEST CHANCES FOR RAINFALL FROM MID TO LATE MORNING THROUGH LATER
TONIGHT ACROSS MY CENTRAL ILLINOIS COUNTIES...AND FROM AROUND MIDDAY
THROUGH TONIGHT FOR MY NORTHERN AREAS.
KJB
&&
LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...
DURING THIS PERIOD THE PRIMARY FOCUS WILL BE WITH THE SECOND STORM
SYSTEM EXPECTED TO DEVELOP AND IMPACT THE GREAT LAKES REGION
CHRISTMAS EVE.
A VERY IMPRESSIVE JET CORE...IN EXCESS OF 150 KT...EXTENDS FROM THE
EASTERN PACIFIC...ONSHORE OVER THE NORTHWESTERN CONUS AT THIS
TIME. THIS JET MAX IS EXPECTED TO BE THE MAIN PLAYER IN THE
DEVELOPMENT OF A SIGNIFICANT STORM SYSTEM BY MID WEEK. MODEL
SOLUTIONS (NAM ASIDE) HAVE COME INTO SOME BETTER AGREEMENT WITH THE
SURFACE LOW. OVERALL...IT APPEARS THAT CYCLOGENESIS WILL BE INDUCED
NEAR THE CENTRAL GULF COAST BY LATE TUESDAY...THEN RACE NORTHWARD
ACROSS THE OHIO VALLEY REGION AND INTO THE CENTRAL GREAT LAKES
REGION BY CHRISTMAS EVE NIGHT. IT STILL APPEARS THAT THE SURFACE LOW
WILL DEEPEN CONSIDERABLY LATE WEDNESDAY AND INTO CHRISTMAS MORNING
AS THE UPPER LEVEL IMPULSE LOOKS TO TAKE ON A NEGATIVE TILT. MOST
OPERATIONAL GUIDANCE HINTS AT HEALTHY 15 TO 20 MB DEEPENING BETWEEN
12 UTC WEDNESDAY AND 12 UTC THURSDAY.
ALTHOUGH TWEAKS TO THE TRACK AND TIMING OF THE SYSTEM ARE STILL A
POSSIBILITY...IT APPEARS THE MAIN UNCERTAINTIES AT THIS POINT WILL BE
THE MESOSCALE DETAILS...AND HENCE WHERE THE BEST DEFORMATION BANDING
WILL OCCUR LATER IN THE DAY CHRISTMAS EVE. BOTH THE GFS AND THE
PAR GFS INDICATE A SLIGHTLY FARTHER NORTH PROGRESSION OF THE
DEFORMATION BAND ACROSS MUSH OF NORTHEASTERN ILLINOIS AND
NORTHWESTERN INDIAN WED AFTERNOON AND EVENING. IN CONTRAST THE
ECMWF...GEM AND UKMET ARE A BIT FARTHER SOUTH...MAINLY IMPACTING MY
SOUTHEASTERN CWA. OVERALL...THERE IS TYPICALLY A STRONG NORTHWESTERN
GRADIENT TO THESE DEFORMATION BANDS...SO THIS COULD LEAD TO A SHARP
CONTRAST IN PRECIPITATION AMOUNTS ACROSS MY CWA.
IT APPEARS THAT PRECIPITATION TYPE WITHIN THIS DEFORMATION BAND WOULD
LIKELY BE IN THE FORM OF SNOW. MODEL SOUNDINGS SUGGEST THAT
BOUNDARY LAYER TEMPERATURES MAY REMAIN A BIT WARM LATE WEDNESDAY AND
EVENING...BUT TYPICALLY DYNAMIC COOLING FROM STRONG FORCING FOR
ASCENT WITHIN THESE DEFORMATION BANDS LEADS TO TRANSITION TO A
PERIOD OF MODERATE TO EVEN HEAVY SNOWFALL. AT THE CURRENT TIME...I
HAVE REMAINED VERY CONSERVATIVE ON SNOW AMOUNTS OVER THE AREA...DUE
TO UNCERTAINTIES ON WHERE THIS POTENTIAL BAND OF HEAVIER PRECIP SETS UP.
HOWEVER...I WOULD NOT BE SURPRISED FOR SOME AREAS...PARTICULARLY IN MY
SOUTHERN AND EASTERN CWA TO END UP WITH SEVERAL INCHES OF
SNOW BY LATE CHRISTMAS EVE. AS SUCH...CHANGES TO SNOW AMOUNTS IS A
GOOD LIKELIHOOD.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* VFR OR BRIEF HIGHER END MVFR CIGS THIS MORNING EXPECTED TO LOWER
TO IFR THIS AFTERNOON AND POSSIBLY LIFR THIS EVENING.
* SPOTTY LIGHT RAIN/SNOW WEST/NORTHWEST OF ORD/MDW EARLY THIS
MORNING.
* RAIN DEVELOPING MIDDAY AND CONTINUING INTO TONIGHT.
* SOUTH-SOUTHEAST WINDS AROUND 10 KT BECOMING SOUTHEAST NEAR 15 KT
BY AFTERNOON.
RATZER
//DISCUSSION...UPDATED 06Z...
FORECAST AREA REMAINS ALONG SOUTHEASTERN PERIPHERY OF LOW STRATUS
WITH CIGS HAVING IMPROVED TO VFR DURING THE LATE EVENING HOURS.
COMPACT MID-LEVEL DISTURBANCE NOTED LIFTING NORTHEAST ACROSS WEST-
CENTRAL IL PRODUCING SPOTTY LIGHT PRECIP IN THE FORM OF LIGHT
RAIN OR RAIN/SNOW AND SOME PATCHY 2500-3000 FT MVFR CIGS...AND
WILL LIKELY AFFECT RFD AND POSSIBLY CHICAGO TERMINALS FOR A FEW
HOURS DURING THE PRE-DAWN HOURS. OTHERWISE...MORE STEADY RAIN IS
EXPECTED TO OVERSPREAD THE AREA MIDDAY AND CONTINUE INTO TONIGHT.
CIGS AND VSBY EXPECTED TO DETERIORATE TO IFR WITH THE RAIN EARLY
THIS AFTERNOON...AND LIKELY TO LIFR TONIGHT AS A WARM FRONT
APPROACHES.
SOUTH-SOUTHEAST WINDS 8-10 KT ARE EXPECTED TO BECOME EAST-
SOUTHEAST NEAR 15 KT BY EARLY AFTERNOON...DECREASING AND BACKING
SOUTH AGAIN TOWARD TUESDAY MORNING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM CONFIDENCE IN CIGS THROUGH PERIOD.
* MEDIUM-HIGH IN GENERAL PRECIP TIMING.
* HIGH CONFIDENCE OTHER ELEMENTS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...MVFR CIGS LIKELY. IFR CIGS POSSIBLE...MAINLY EARLY.
WEDNESDAY...MVFR CIGS LIKELY. CHANCE OF RA/SN.
THURSDAY...CHANCE OF MVFR CIGS...MAINLY EARLY.
FRIDAY...CHANCE OF MVFR CIGS. CHANCE OF -RA/-SN
SATURDAY...MVFR CIGS LIKELY. CHANCE OF FLURRIES.
IZZI
&&
.MARINE...
233 AM CST
FORECAST FOR LAKE MICHIGAN REMAINS COMPLICATED THIS MORNING...WITH
TWO AREAS OF LOW PRESSURE EXPECTED TO BRING PERIODS OF STRONG WINDS
ACROSS THE LAKE OVER THE NEXT SEVERAL DAYS.
THE FIRST LOW WAS MOVING SOUTHEAST ACROSS THE DAKOTAS EARLY THIS
MORNING...WITH A TIGHTENING PRESSURE GRADIENT EXTENDING EAST INTO
THE WESTERN LAKES. OBSERVATION PLATFORMS ALONG THE WEST AND
NORTHWEST SHORES OF THE LAKE WERE REPORTING SOUTH WINDS IN THE 25-30
KT RANGE...WITH WINDS TO 30 KT EXPECTED TO BACK TO THE EAST AS THE
LOW MOVES TO THE IOWA-MISSOURI BORDER TONIGHT. THE LOW WILL THEN
BEGIN TO FILL AS IT TURNS NORTHEAST...LIFTING ACROSS NORTHERN LAKE
MICHIGAN LATE TUESDAY.
EXPECTATIONS ARE THAT A SECOND LOW WILL DEVELOP TO THE SOUTH ACROSS
THE TENNESSEE AND OHIO RIVER VALLEYS BY EARLY WEDNESDAY MORNING...
DEEPENING AS IT LIFTS NORTHWARD INTO THE CENTRAL GREAT LAKES REGION
BY WEDNESDAY EVENING. MODELS CONTINUE TO SHOW DIFFERENCES IN THE
EXACT TRACK AND STRENGTH OF THE LOW AS IT PASSES EAST OF LAKE
MICHIGAN...AS WELL AS NORTH AND NORTHWEST WIND SPEEDS WEDNESDAY
AFTERNOON INTO THURSDAY MORNING. AT THIS POINT...IT APPEARS THAT
WINDS OF 25-30 KT ARE LIKELY...AND POSSIBLY STILL GALES FOR A TIME
IF THE LOW DEEPENS A LITTLE FASTER. WINDS THEN LOOK TO DIMINISH AND
BACK TO THE WEST AND THEN SOUTHWEST CHRISTMAS DAY. MODELS ARE IN
BETTER AGREEMENT IN ANOTHER LOW APPROACHING AND LIFTING ACROSS THE
NORTHERN LAKES FRIDAY AND FRIDAY NIGHT.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP TO WILMETTE HARBORS UNTIL 3 AM TUESDAY.
SMALL CRAFT ADVISORY...LMZ741-LMZ742...NOON MONDAY TO 3 AM
TUESDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
330 AM CST Mon Dec 22 2014
.SHORT TERM...(Today)
ISSUED AT 328 AM CST MON DEC 22 2014
Strong jet (175kts) over the Pacific Northwest digging southeast
into a deepening central Plains trof this morning will eject an
initial wave into our area today bringing rain along with mild
temperatures. Low pressure is expected to consolidate over north
central Missouri by late this afternoon and then track thru
northwest Illinois early this evening. The southerly flow in advance
of the storm system will quickly saturate the lower levels of the
atmosphere with rain overspreading the area from southwest to
northeast this morning. Some weak isentropic lift and moisture
convergence early this morning has produced some spotty light
rain/drizzle over parts of central Illinois and expect that to
continue before the stronger forcing arrives later this morning.
Models suggest the strongest lift moves into our area from mid
morning thru the early evening hours, so high POPs are warranted
over most of the forecast area today. Despite the cloud cover and
precip, mild temperatures to prevail again today with afternoon
readings in the mid to upper 40s.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 328 AM CST MON DEC 22 2014
Increased rain chances to categorical this evening with supporting
lift of low level jet and short waves ejecting ne from
central/southern plains into IL tonight. SPC has thunder chances
just southeast of IL. Rain chances to diminish from sw to ne
during overnight into Tue morning as energy shifts north of
central IL Tue. Appears to be a lull in rain chances Tue and Tue
evening over much of central IL with best rain chances shifting to
our north with surface low pressure over southern WI Tue afternoon
and also to our se. Mild lows tonight of 40-45F and highs Tue
range from mid 40s over IL river valley and lower 50s in southeast
IL.
00Z models still not in good agreement with development of strong
low pressure system from northwestern Gulf of Mexico and deepening
nne across the ohio river valley Wed. NAM model appears is dry over
IL Tue night and Wed but feel its low pressure track is too far east
near the foothills of the Appalachians. Will use a blend of the
ECMWF/GEM and GFS models for the storm system during midweek. Have
precipitation chances spreading back northward across central IL
overnight Tue night into Wed and diminishing from west to east by
overnight Wed night. Warm enough for rain Tue evening, then mixing
with and gradually changing to light snow later Tue night into Wed
from west to east. Deformation band of light snow accumulations
likely to set up on back side of storm system, though placement of
this band is still too difficult to pinpoint down. WPC keeps snow
accumulations less than 1 inch over central/eastern IL on
Wed/Christmas eve. Cooler highs Wed in the upper 30s to near 40F
eastern IL and will likely slip during the afternoon with increasing
WNW winds.
Christmas Day still looks dry with return of some sunshine as strong
storm system lifts into Quebec and 1025 mb surface high pressure
over gulf of mexico ridges northward into the ohio river valley.
Highs in the lower 40s Thu/Christmas Day, so any snow that does fall
Wed will likely melt.
Models have another low pressure taking a track more nw of central
IL Friday and lifting into the western Great Lakes Friday night.
Have small chances of light precipitation Fri/Fri night and then dry
for the weekend. Models showing yet another southern low pressure
system over gulf of Mexico Sat night/Sunday but for now will keep
precipitation chances south of central IL. Highs Fri in the low to
mid 40s, cool to highs in upper 20s to mid 30s this weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1133 PM CST SUN DEC 21 2014
Moisture channel satellite imagery shows vort max about Macomb
now, continuing to track to the northeast. Few sprinkles ahead of
the vort max moved to the northeast of area. HRRR model still
shows IFR cigs developing north into the central TAF sites around
15z and so timed IFR conditions coming into area accordingly. As
the upper system gets closer, lowered the vsb to IFR levels.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Goetsch
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1144 PM CST SUN DEC 21 2014
.UPDATE...
914 PM CST
WHILE THERMAL PROFILES ARE STILL A BIT TRICKY IN OUR WESTERN CWA
OVERNIGHT...FEELING IS THAT IF SOME PRECIP SNEAKS IN OVERNIGHT...SURFACE
TEMPS WOULD BE AROUND FREEZING OR POSSIBLY SLIGHTLY WARMER WHICH
WOULD MITIGATE IMPACTS SIGNIFICANTLY. MLI IS REPORTING UNKNOWN
PRECIP THIS EVENING BUT WITH A SURFACE TEMP IN THE MID 30S. WHEN
PRECIP ARRIVES IN THE MORNING IN THE WEST AND SOUTH...TEMPS SHOULD
LARGELY STILL BE ABOVE FREEZING. WHILE THE CHANCE IS NOT ZERO FOR
SOME LIGHT FZDZ OR SLEEET...CONFIDENCE IS LOW.
KMD
&&
.SHORT TERM...
246 PM CST
THROUGH TUESDAY...
TONIGHT THROUGH TUESDAY...
BROAD SFC RIDGE HAS BECOME CENTERED OVER THE NORTHEAST CONUS...AND
CONTINUES TO SLOWLY DRIFT EAST/NORTHEAST. THE GRADIENT ACROSS THE
GREAT LAKES HAS REMAINED LIGHT THIS AFTN...WITH A MAINLY SOUTHERLY
FLOW. CLOUDS REMAIN LOCKED IN ACROSS THE FORECAST AREA...WITH SOME
CLEARING JUST SOUTHEAST OF THE CWFA IN CENTRAL/NORTHERN IN. SFC
TEMPS HAVE BEEN ABLE TO WARM TO THE MID/UPR 30S...WITH DEW PTS
HOVERING AROUND 30-33 DEG. MOST THE EVENING WILL REMAIN DRY...WITH
THE WEAK MID-LVL WAVE SLIDING NORTHEAST ACROSS IOWA/WISC WITH SOME
LGT SNOW...OTHERWISE MOST OF THE FORECAST AREA SHUD REMAIN DRY THRU
THE OVERNIGHT PERIOD.
500MB VORT BEGINS TO LIFT NORTHEAST FROM THE CENTRAL PLAINS BEFORE
DAYBREAK MON...PUSHING THE MOIST CHANNEL FURTHER EAST ACROSS THE
FORECAST AREA. WITH SOUNDINGS SUGGESTING A WARM WEDGE DEVELOPING
ALOFT...P-TYPE COULD BE A CHALLENGE ARND DAYBREAK. GUIDANCE WOULD
SUGGEST TEMPS COULD BE WARM ENOUGH TO LIMIT PRECIP TO LGT
RAIN...WITH NEAR SFC TEMPS HOLDING ARND THE FREEZING MARK...SO HAVE
CONTINUED THE MENTION OF FZRA MAINLY SOUTH OF ROCKFORD. CLOSER TO
ROCKFORD THE THERMAL PROFILE IS A LITTLE MORE TRICKY AND COULD ALLOW
SOME LGT SNOW/SLEET AT THE ONSET CHANGING TO LGT RA/FZRA BEFORE
MIDDAY. THROUGHOUT THE AFTN TEMPS WILL STEADILY WARM...NEARING 40
DEG IN MOST LOCATIONS AS WARM/MOIST AIR CONTINUES TO ADVECT NORTH
ACROSS THE CWFA. MOST GUIDANCE INDICATES LGT RAIN WILL PERSIST THRU
THE AFTN/EVE HOURS...WITH THE DRY WEDGE NOT ARRIVING UNTIL CLOSER TO
DAYBREAK TUE. LOCAL SOLUTION SUGGESTS SLIGHTLY EARLIER WITH BRINGING
A TEMPORARY END TO THE PRECIP...JUST AFT MIDNIGHT MON NGT.
TEMPS OVERNIGHT WILL REMAIN MILD IN THE UPR 30S/NEAR 40. WITH THE
TROUGH TAKING ON A NEGATIVE TILT MIDDAY TUE...THE SFC LOW WILL BE
WRAPPED UP ACROSS CENTRAL WISC. GUIDANCE HAS BOUNCED AROUND POSSIBLY
KEEPING EITHER DRY/LOW CHC POPS OVER NORTHERN IL/NORTHWEST IN
TUE/TUE AFTN...BUT HAVE OPTED TO HOLD ONTO A SLT CHC OF RAIN. WITH
WARM AIR CONTINUING TO ADVECT NORTH...SFC TEMPS COULD PUSH INTO THE
MID/UPR 40S WITH A FEW LOCATIONS IN THE SOUTHEAST REACHING 50 DEG.
BY TUE EVENING THE TROUGH AXIS IS PROGGED TO EJECT ANOTHER SFC LOW
ACROSS THE GULF STATES...THEN QUICKLY LIFT NORTH ACROSS THE TENN
VALLEY LATE TUE NGT. MOISTURE WILL FILL BACK IN ACROSS THE FORECAST
AREA TUE NGT...WITH RAIN BECOMING MIXED WITH SNOW OVERNIGHT. TEMPS
WILL SLOWLY COOL...SO THE PERIOD OF RAIN/SNOW MIX COULD LINGER
AWHILE.
BEACHLER
&&
.LONG TERM...
246 PM CST
WEDNESDAY THROUGH SUNDAY...
MID-WEEK ENSEMBLES CONTINUE TO PROG A SLIGHT STRENGTHENING TO THE
DOWNSTREAM RIDGE OVER THE CANADIAN MARITIME...WHICH WILL LIMIT HOW
FAR EAST THE SECONDARY LOW WILL PROGRESS. OPERATIONAL SOLUTIONS
CONTINUE TO LIFT THE STRENGTHENING LOW NORTH ACROSS THE OHIO VALLEY
WED AFTN...AND QUICKLY NORTH OF LAKE HURON BY LATE WED NGT. WRAP
AROUND MOISTURE AND COOLER AIR WILL BRING SOME LGT SNOW TO NORTHERN
IL WED.
FOR CHRISTMAS DAY THE DOWNSTREAM RIDGE WILL BEGIN TO
WEAKEN...ALLOWING THE MID-LVL TROUGH TO BECOME PROGRESSIVE AND PUSH
EAST. THIS SHUD BRING AN END TO THE LGT SNOW/FLURRIES BY DAYBREAK.
TEMPS SHUD RETURN TO THE MID/UPR 30S...ALONG WITH PERHAPS SOME
BREAKS IN THE CLOUD COVER BY THE AFTN. MID-LVL HEIGHTS SHUD START TO
INCREASE THUR NGT/FRI...HOWEVER THIS LOOKS TO BE SHORT-LIVED AS YET
ANOTHER TROUGH IS PROGGED TO DIG SOUTH FROM THE CANADIAN ROCKIES
INTO THE NORTHERN PLAINS. THE STRONGER PUSH OF COLDER AIR LOOKS TO
ARRIVE SAT...ALTHOUGH THIS MAY ONLY BE A SHORT DURATION WITH THE
SEMI-ZONAL PATTERN SETTING UP FOR THE SECOND HALF OF THE WEEKEND.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* VFR OR BRIEF HIGHER END MVFR CIGS THIS MORNING EXPECTED TO LOWER
TO IFR THIS AFTERNOON AND POSSIBLY LIFR THIS EVENING.
* SPOTTY LIGHT RAIN/SNOW WEST/NORTHWEST OF ORD/MDW EARLY THIS
MORNING.
* RAIN DEVELOPING MIDDAY AND CONTINUES INTO TONIGHT.
* SOUTH-SOUTHEAST WINDS AROUND 10 KT BECOMING SOUTHEAST NEAR 15 KT
BY AFTERNOON.
RATZER
//DISCUSSION...UPDATED 06Z...
FORECAST AREA REMAINS ALONG SOUTHEASTERN PERIPHERY OF LOW STRATUS
WITH CIGS HAVING IMPROVED TO VFR DURING THE LATE EVENING HOURS.
COMPACT MID-LEVEL DISTURBANCE NOTED LIFTING NORTHEAST ACROSS WEST-
CENTRAL IL PRODUCING SPOTTY LIGHT PRECIP IN THE FORM OF LIGHT
RAIN OR RAIN/SNOW AND SOME PATCHY 2500-3000 FT MVFR CIGS...AND
WILL LIKELY AFFECT RFD AND POSSIBLY CHICAGO TERMINALS FOR A FEW
HOURS DURING THE PRE-DAWN HOURS. OTHERWISE...MORE STEADY RAIN IS
EXPECTED TO OVERSPREAD THE AREA MIDDAY AND CONTINUE INTO TONIGHT.
CIGS AND VSBY EXPECTED TO DETERIORATE TO IFR WITH THE RAIN EARLY
THIS AFTERNOON...AND LIKELY TO LIFR TONIGHT AS A WARM FRONT
APPROACHES.
SOUTH-SOUTHEAST WINDS 8-10 KT ARE EXPECTED TO BECOME EAST-
SOUTHEAST NEAR 15 KT BY EARLY AFTERNOON...DECREASING AND BACKING
SOUTH AGAIN TOWARD TUESDAY MORNING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN CIGS THROUGH PERIOD.
* MEDIUM-HIGH IN GENERAL PRECIP TIMING.
* HIGH CONFIDENCE OTHER ELEMENTS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...MVFR CIGS LIKELY. IFR CIGS POSSIBLE...MAINLY EARLY.
WEDNESDAY...MVFR CIGS LIKELY. CHANCE OF RA/SN.
THURSDAY...CHANCE OF MVFR CIGS...MAINLY EARLY.
FRIDAY...CHANCE OF MVFR CIGS. CHANCE OF -RA/-SN
SATURDAY...MVFR CIGS LIKELY. CHANCE OF FLURRIES.
IZZI
&&
.MARINE...
204 PM CST
SMALL CRAFT ADVISORY...KEPT THE CURRENT SMALL CRAFT AS IS AND
EXPANDED IT TWO ZONES SOUTH THROUGH CALUMET HARBOR. WAVES WILL
BECOME HAZARDOUS OVERNIGHT NORTH OF WILMETTE HARBOR AND THEN WINDS
AND WAVES WILL BECOME HAZARDOUS TOMORROW AFTERNOON. MARGINAL SMALL
CRAFT CONDITIONS ARE POSSIBLE ALONG THE INDIANA NEARSHORE WATERS AND
DO NOT HAVE ENOUGH CONFIDENCE TO ISSUE A SMALL CRAFT ADVISORY AT
THIS TIME.
HIGH PRESSURE IS OVER THE EAST COAST WHILE THE NEXT LOW IS OVER THE
NORTHERN PLAINS. SOUTH WINDS HAVE INCREASED TO 15-25 KT ACROSS THE
LAKE AND WILL CONTINUE TO INCREASE TO 30 KT THIS AFTERNOON. WINDS
BECOME SOUTHEAST TOMORROW AS THE LOW MOVES OVER THE EASTERN PLAINS
AND WEAKENS. THE LOW THEN WEAKENS OVER WISCONSIN TUESDAY AFTERNOON
THROUGH TUESDAY NIGHT. WINDS WEAKEN ACROSS THE LAKE MONDAY NIGHT AND
BECOME WEST TO NORTHWEST 10-15 KT TUESDAY NIGHT. A SECOND LOW FORMS
OVER THE SOUTHERN MISSISSIPPI VALLEY TUESDAY NIGHT AND QUICKLY
DEEPENS AS IT MOVES NORTH. GUIDANCE DIFFERS ON HOW FAR TO OUR EAST
THE LOW WILL PASS...BUT THINKING IT WILL BE OVER THE EASTERN GREAT
LAKES. GUIDANCE HAS ALSO BACKED OFF ON WIND SPEEDS BEHIND THE LOW
AND WILL ONLY CARRY OCCASIONAL GALES IN THE GLF AT THIS TIME. SO
HAVE WEST TO NORTHWEST WINDS INCREASING TO 30 KT WEDNESDAY NIGHT.
THE BEST WINDOW FOR GALES WOULD BE LATE WEDNESDAY NIGHT. THE LOW
THEN CONTINUES NORTHEAST INTO QUEBEC THURSDAY AND HAVE SOUTHWEST
WINDS DECREASING THURSDAY. ANOTHER LOW SLIDES ACROSS THE PLAINS
THURSDAY AFTERNOON AND WILL IMPACT THE LAKE FRIDAY. GUIDANCE
DIFFERS ON HOW STRONG THE LOW WILL BE WHEN IT MOVES OVER THE
LAKE...SO HAVE LOW CONFIDENCE IN THE FORECAST LATE NEXT WEEK.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP TO WILMETTE HARBORS UNTIL 3 AM TUESDAY.
SMALL CRAFT ADVISORY...LMZ741-LMZ742...NOON MONDAY TO 3 AM
TUESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1137 PM CST Sun Dec 21 2014
.UPDATE...
ISSUED AT 904 PM CST SUN DEC 21 2014
Moisture channel satellite imagery depicts minor vort max near
Quincy moving to the northeast. Radar showing development of some
very light pcpn ahead of the vort max over north central IL.
Updated the grids for sprinkles for few hours late this evening.
Clouds have come back into the region with the wave.
&&
.SHORT TERM...(Tonight)
ISSUED AT 256 PM CST SUN DEC 21 2014
Low pressure currently over southern Alberta will track into eastern
South Dakota by 12z Mon. Ahead of the system, a tightening pressure
gradient will produce southeasterly winds of 10 to 15 mph across
central Illinois tonight. Due to these sustained winds and a partly
to mostly cloudy sky, overnight low temperatures will be a few
degrees warmer than last night and several degrees warmer than
either the MAV or MET guidance. Lows will once again be coolest
across the SE KILX CWA where skies will initially be mostly clear
and warmest across the W/NW where clouds will hold firm. Readings
will range from the upper 20s near the Indiana border to the middle
30s along/west of I-55. Any precipitation associated with the
approaching system will remain west of the Mississippi River until
later Monday morning, as forecast soundings remain dry through 12z.
&&
.LONG TERM...(Monday through Sunday)
ISSUED AT 256 PM CST SUN DEC 21 2014
Beginning to look like a good news/bad news scenario setting up with
the storm system expected to impact central and southeast Illinois
from Monday into Christmas Eve. If recent model trends hold, the
good news will be that significant weather related travel impacts
are not expected on Christmas Eve in the area. The bad news, for
some, would be that a "White Christmas" is looking less likely
locally.
We are still looking at active weather the next few days as a
complex, slow moving, storm system impacts the area. A 160+ kt
upper-level jet crashing into the Pacific NW & northern Rockies will
continue to amplify troffing over the middle of the nation, a trof
that will be with us for a few days.
A closed upper low is expected to develop over the northern
Plains/upper Midwest Monday, nearly vertically stacked with an
associated surface low. The WAA/isentropic lift ahead of these lows
will be accompanied by a periods of rainfall from Monday into Monday
night. Then, another vigorous piece of upper energy will round the
base of the mean trof Tuesday into Wednesday, accompanied by the
development of another surface low. This second low will become the
dominant low, with the first low expected to dissipate. A dry slot
is progged to wrap around the initial upper low, no doubt aided by
the secondary wave intercepting much of the deeper moisture. This
dry slot may result in much of Tuesday/Tuesday night ending up dry
across the northwest 1/2 of the forecast area, certainly drier than
it looked yesterday. The southeast 1/2 of the forecast area should
see rain chances persisting Tuesday and Tuesday night, as this area
will be closer to the track of the secondary wave. The remaining
precipitation will change over to light snow on Christmas Eve, but
model agreement is strengthening and this suggests that snowfall
will not be a significant impact across the forecast area.
Mostly dry conditions are expected by Christmas Day as the system
heads northeast into Canada. Another, much weaker, system is progged
to impact the area by Friday. However, guidance suggests that this
system will have minimal moisture to work with until it moves east
of the forecast area. This is because there will not have been much
time for the atmosphere to recover from the cold/dry advection in
the wake of the midweek system. So, only have a slight chance of
rain and/or snow for Friday into Friday night. While temperatures
will be above normal for much of this week, they will trend below
normal behind Friday`s system.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1133 PM CST SUN DEC 21 2014
Moisture channel satellite imagery shows vort max about Macomb
now, continuing to track to the northeast. Few sprinkles ahead of
the vort max moved to the northeast of area. HRRR model still
shows IFR cigs developing north into the central TAF sites around
15z and so timed IFR conditions coming into area accordingly. As
the upper system gets closer, lowered the vsb to IFR levels.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Goetsch
SHORT TERM...Barnes
LONG TERM...Bak
AVIATION...Goetsch
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
948 AM EST MON DEC 22 2014
.UPDATE...
NEAR TERM FOR THE REST OF TODAY HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 327 AM EST MON DEC 22 2014
AN UPPER TROUGH AND A COUPLE OF AREAS OF LOW PRESSURE WILL BRING
RAIN TO CENTRAL INDIANA TODAY INTO WEDNESDAY...WITH PERHAPS SOME
SNOW WEDNESDAY NIGHT. ANOTHER SYSTEM WILL BRING ADDITIONAL CHANCES
FOR PRECIPITATION FRIDAY AND SATURDAY. NEAR TO ABOVE AVERAGE
TEMPERATURES THIS WEEK WILL RETURN TO COOLER THAN AVERAGE FOR THE
WEEKEND.
&&
.NEAR TERM.../REST OF TODAY/
ISSUED AT 948 AM EST MON DEC 22 2014
.UPDATE...RAISED RAIN CHANCES A LITTLE OVER CENTRAL AND WESTERN
SECTIONS AS RADAR LOOPS HAS SHOWN A PRETTY GOOD PROGRESSION OF LIGHT
RAIN INTO OUR WESTERN SECTIONS AND MODELS SHOW THIS TREND CONTINUING
THIS AFTERNOON. OTHERWISE...ONLY MINOR TWEAKS MADE TO GRIDS AS
PREVIOUS FORECAST SEEMS TO BE ON TRACK.
PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
ISENTROPIC LIFT WILL INCREASE TODAY AS AN UPPER TROUGH AND SURFACE
WARM FRONT MOVE TOWARD CENTRAL INDIANA. BEST FORCING ARRIVES LATE IN
THE DAY WHEN 850MB WINDS APPROACH 50KT AND AN UPPER JET MOVES CLOSER
TO THE AREA.
ANY PRECIPITATION WILL HAVE TO FIGHT THE DRY LOWER LEVELS OF THE
ATMOSPHERE INITIALLY. SOUTHEAST WINDS AT THE SURFACE WILL AID IN
KEEPING THE LOWER LEVELS DRY. THUS IT WILL TAKE THE ATMOSPHERE A
WHILE TO MOISTEN UP.
GIVEN THE ABOVE...WENT HIGHEST POPS TODAY AT THE END OF THE TODAY
PERIOD. GRADUALLY INCREASED POPS DURING THE DAY. BY LATE DAY WENT
LIKELY POPS FAR WEST...CHANCE CENTRAL...AND SLIGHT CHANCE FAR EAST.
CLOUDS WILL INCREASE/THICKEN THROUGH THE DAY. A BLEND OF MODELS
LOOKS BEST FOR HIGH TEMPERATURES...AND THIS ENDS UP NEAR TO A LITTLE
COOLER THAN MOS SUGGESTS.
&&
.SHORT TERM.../TONIGHT THROUGH WEDNESDAY NIGHT/
ISSUED AT 327 AM EST MON DEC 22 2014
FOCUS IS ON PRECIPITATION CHANCES THROUGH THE PERIOD. THREW OUT THE
NAM AS ITS SOLUTION OF BRINGING A SURFACE LOW NEAR THE APPALACHIANS
LOOKS UNREALISTIC. GFS/ECMWF/CANADIAN MODELS ARE SIMILAR AND LOOK
MORE REASONABLE...SO USED A BLEND OF THEIR SOLUTIONS.
RAIN WILL CONTINUE TO OVERSPREAD CENTRAL INDIANA TONIGHT WITH FIRST
A WARM FRONT THEN A COLD FRONT MOVING THROUGH THE AREA. 850MB JET
WILL PROVIDE GOOD MOISTURE AND FORCING...AND UPPER TROUGH/UPPER JET
WILL BRING ADDITIONAL FORCING. THUS WENT CATEGORICAL POPS ALL AREAS
TONIGHT. LOWERED POPS OVERNIGHT AS SOME DRIER AIR WORKS IN BEHIND
THE COLD FRONT.
MODELS NOW SHOWING A DRY SLOT ACROSS CENTRAL INDIANA FOR MUCH OF
TUESDAY. THIS SEEMS REASONABLE WITH FIRST SURFACE AND UPPER SYSTEMS
MOVING OFF THE NORTH...AND NEXT UPPER LOW AND SURFACE LOW STILL
ORGANIZING TO THE SOUTH/SOUTHWEST. HOWEVER DO NOT BELIEVE THE VERY
DRY GFS GIVEN THAT ANY WEAK UPPER IMPULSES COULD GENERATE SOME
SHOWERS.
THUS WENT MAINLY CHANCE POPS THROUGH THE DAY TUESDAY ACROSS THE
AREA. KEPT HIGHER POPS EAST DURING THE MORNING TO ACCOUNT FOR RAIN
ALONG THE EXITING SURFACE FRONT.
TUESDAY NIGHT POPS WILL INCREASE ONCE AGAIN AS THE NEXT SYSTEM
APPROACHES FROM THE SOUTH. BY 06Z WENT LIKELY POPS MOST AREAS.
ON WEDNESDAY A SURFACE LOW WILL MOVE THROUGH THE AREA. MODELS STILL
UNCERTAIN ON EXACT PATH...BUT IT SHOULD BE IN THE GENERAL AREA OF
CENTRAL INDIANA TO WESTERN OHIO. WENT HIGH END LIKELY POPS...AND MAY
NEED TO UP THEM TO CATEGORICAL AS WE GET CLOSER.
WITH THE MORE WESTERN TRACKS OF THE MODELS GAINING FAVOR /GFS
ENSEMBLE MEAN AND PARALLEL GFS ARE FARTHER WEST THAN OPERATIONAL GFS
AND ECMWF/ FEEL THAN RAIN WILL BE THE PRIMARY PRECIPITATION TYPE
THROUGH THE DAY WEDNESDAY. WENT WITH CHANCE OF SNOW MIXING IN ACROSS
ROUGHLY THE WEST HALF OF CENTRAL INDIANA IN THE LATE AFTERNOON AS
COLDER AIR STARTS TO WORK IN.
MOST OF THE FORCING WILL BE OFF TO THE EAST WEDNESDAY NIGHT SO WENT
CHANCE POPS. WILL HAVE TO WATCH CLOSELY THOUGH IN CASE DEFORMATION
ZONE OR EVEN A TROWAL BRING BETTER CHANCES. WENT SNOW AS THE
PRECIPITATION TYPE WITH COLDER AIR QUICKLY MOVING IN. AT THE MOMENT
WILL KEEP ANY SNOWFALL AMOUNTS LESS THAN AN INCH.
FOR TEMPERATURES THROUGH THE PERIOD GENERALLY STUCK WITH A BLEND OF
GFS/ECMWF/MOS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 253 AM EST MON DEC 22 2014
STRONG SYSTEM SET TO IMPACT THE REGION CHRISTMAS EVE WILL LIFT INTO
QUEBEC BY EARLY CHRISTMAS MORNING...WILL ANY LEFTOVER LIGHT SNOW
SHOWERS DEPARTING AROUND OR SHORTLY BEFORE DAYBREAK. SURFACE RIDGING
WILL IMMEDIATELY EXPAND INTO THE OHIO VALLEY ON THURSDAY WITH CLOUDS
GRADUALLY DIMINISHING AS WINDS TURN SOUTHERLY. FOCUS SHIFTS ABRUPTLY
TO NEXT SURFACE WAVE EJECTING OUT OF THE CENTRAL PLAINS AS YET
ANOTHER SHARP UPPER TROUGH DIVES INTO THE NORTHERN ROCKIES. OVERALL
MODEL CONSENSUS IS NOT TOO BAD AT THIS POINT WITH RESPECT TO THE
SURFACE LOW TRACK INTO THE WESTERN GREAT LAKES BY FRIDAY NIGHT.
SOUTHERLY FLOW AND WARM ADVECTION AHEAD OF THIS FEATURE WILL BRING
MILDER AIR NORTH WITH ANY PRECIPITATION FALLING AS RAIN INTO FRIDAY
EVENING. COLDER AIR WILL SPILL IN LATE AS A COLD FRONT PASSES
THROUGH THE REGION...WITH PRECIP POSSIBLY MIXING WITH OR CHANGING TO
LIGHT SNOW INTO SATURDAY BEFORE ENDING.
REMAINDER OF THE EXTENDED QUITE A BIT MORE CONVOLUTED AS MODELS
EXHIBITING DIFFERENCES IN HANDLING OF SUBSEQUENT WAVES ALOFT
TRAVERSING THE LOWER 48. THE ECMWF AND GGEM STARTING TO FAVOR
SECONDARY SURFACE WAVE DEVELOPMENT ON THE TRAILING PART OF THE
AFOREMENTIONED COLD FRONT...BRINGING THE FEATURE NORTHEAST OUT OF
THE WESTERN GULF OF MEXICO UP INTO THE OHIO AND TENNESSEE VALLEYS BY
EARLY SUNDAY IN TANDEM WITH THE WAVE ALOFT. NOT SURPRISINGLY...OP
GFS/PARALLEL GFS AND PRETTY MUCH ALL OF THE GFS ENSEMBLE MEMBERS
PAINT A COMPLETELY DIFFERENT PICTURE...WITH ANY SECONDARY WAVE
DEVELOPMENT ON THE FRONT BEING SUPPRESSED ALONG THE GULF COAST WITH
NO UPPER SUPPORT PRESENT.
WILL MAINTAIN A DRY CHILLY FORECAST FOR THE SECOND HALF OF THE
WEEKEND TO MAINTAIN CONTINUITY FROM PREVIOUS FORECASTS...BUT IT WILL
BE INTERESTING TO SEE IF THE GLOBAL MODELS MAINTAIN THIS NEW IDEA OF
BRINGING A SECONDARY WAVE NORTH WITH POTENTIALLY ADDITIONAL
OPPORTUNITIES FOR WINTRY PRECIP SATURDAY NIGHT AND SUNDAY. NOT
ANTICIPATING ANY BETTER MODEL CONSENSUS FOR AT LEAST A FEW MORE
DAYS...ESPECIALLY CONSIDERING THE CHAOTIC MODEL PERFORMANCE
RECENTLY. DEFINITELY SOMETHING TO MONITOR GOING FORWARD.
&&
.AVIATION /DISCUSSION FOR 221200Z TAF ISSUANCE/...
ISSUED AT 922 AM EST MON DEC 22 2014
1423Z UPDATE...PUSHED BACK TIMING FOR MFVR BY AN HOUR FOR A FEW OF
THE SITES. OTHERWISE NO OTHER CHANGES NEEDED AT THIS TIME.
PREVIOUS DISCUSSION FOLLOWS.
DETERIORATING FLYING CONDITIONS THROUGH THE PERIOD WITH RAIN
IMPACTING THE TERMINALS THIS AFTERNOON INTO TONIGHT.
CLOUD DECK HAS QUICKLY ENCOMPASSED THE TERMINALS OVER THE LAST FEW
HOURS. MOISTURE WILL CONTINUE TO INCREASE AHEAD OF A WARM FRONT...
WITH CEILINGS EXPECTED TO SINK INTO MVFR CATEGORY BY MID MORNING.
LIGHT RAIN EXPANDING IN COVERAGE NEAR THE MISSISSIPPI RIVER AND
WILL CONTINUE NORTHEAST OVER THE NEXT FEW HOURS. HRRR KEEPS BULK
OF THE PRECIP THROUGH EARLY AFTERNOON WEST OF THE TERMINALS...WITH
ONLY KHUF AND POSSIBLY KLAF BEING IMPACTED.
AS LOW PRESSURE AND ITS ASSOCIATED WARM FRONT APPROACH THE REGION
LATER THIS AFTERNOON INTO THE EVENING HOWEVER...EXPECT WIDESPREAD
RAIN AND IFR CONDITIONS TO DEVELOP OVER CENTRAL INDIANA. SOUTHEAST
WINDS WILL STEADILY INCREASE TO 10-15KTS BY THIS EVENING...
EVENTUALLY VEERING TO A MORE SOUTHERLY DIRECTION AND BECOMING
GUSTY BY DAYBREAK TUESDAY AS THE WARM FRONT PASSES THROUGH THE
FORECAST AREA. RAIN WILL DECREASE IN COVERAGE AFTER 06Z AS THE
SURFACE LOW LIFTS INTO NORTHERN ILLINOIS...BUT LOW STRATUS WILL
PERSIST AS MODEL SOUNDINGS AND 925/950MB RH PROGS MAINTAIN DEEP
LOW LEVEL MOISTURE BENEATH AN INVERSION.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50/JH
SHORT TERM...50
LONG TERM....RYAN
AVIATION...SMF/RYAN
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
925 AM EST MON DEC 22 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 327 AM EST MON DEC 22 2014
AN UPPER TROUGH AND A COUPLE OF AREAS OF LOW PRESSURE WILL BRING
RAIN TO CENTRAL INDIANA TODAY INTO WEDNESDAY...WITH PERHAPS SOME
SNOW WEDNESDAY NIGHT. ANOTHER SYSTEM WILL BRING ADDITIONAL CHANCES
FOR PRECIPITATION FRIDAY AND SATURDAY. NEAR TO ABOVE AVERAGE
TEMPERATURES THIS WEEK WILL RETURN TO COOLER THAN AVERAGE FOR THE
WEEKEND.
&&
.NEAR TERM.../TODAY/
ISSUED AT 327 AM EST MON DEC 22 2014
ISENTROPIC LIFT WILL INCREASE TODAY AS AN UPPER TROUGH AND SURFACE
WARM FRONT MOVE TOWARD CENTRAL INDIANA. BEST FORCING ARRIVES LATE IN
THE DAY WHEN 850MB WINDS APPROACH 50KT AND AN UPPER JET MOVES CLOSER
TO THE AREA.
ANY PRECIPITATION WILL HAVE TO FIGHT THE DRY LOWER LEVELS OF THE
ATMOSPHERE INITIALLY. SOUTHEAST WINDS AT THE SURFACE WILL AID IN
KEEPING THE LOWER LEVELS DRY. THUS IT WILL TAKE THE ATMOSPHERE A
WHILE TO MOISTEN UP.
GIVEN THE ABOVE...WENT HIGHEST POPS TODAY AT THE END OF THE TODAY
PERIOD. GRADUALLY INCREASED POPS DURING THE DAY. BY LATE DAY WENT
LIKELY POPS FAR WEST...CHANCE CENTRAL...AND SLIGHT CHANCE FAR EAST.
CLOUDS WILL INCREASE/THICKEN THROUGH THE DAY. A BLEND OF MODELS
LOOKS BEST FOR HIGH TEMPERATURES...AND THIS ENDS UP NEAR TO A LITTLE
COOLER THAN MOS SUGGESTS.
&&
.SHORT TERM.../TONIGHT THROUGH WEDNESDAY NIGHT/
ISSUED AT 327 AM EST MON DEC 22 2014
FOCUS IS ON PRECIPITATION CHANCES THROUGH THE PERIOD. THREW OUT THE
NAM AS ITS SOLUTION OF BRINGING A SURFACE LOW NEAR THE APPALACHIANS
LOOKS UNREALISTIC. GFS/ECMWF/CANADIAN MODELS ARE SIMILAR AND LOOK
MORE REASONABLE...SO USED A BLEND OF THEIR SOLUTIONS.
RAIN WILL CONTINUE TO OVERSPREAD CENTRAL INDIANA TONIGHT WITH FIRST
A WARM FRONT THEN A COLD FRONT MOVING THROUGH THE AREA. 850MB JET
WILL PROVIDE GOOD MOISTURE AND FORCING...AND UPPER TROUGH/UPPER JET
WILL BRING ADDITIONAL FORCING. THUS WENT CATEGORICAL POPS ALL AREAS
TONIGHT. LOWERED POPS OVERNIGHT AS SOME DRIER AIR WORKS IN BEHIND
THE COLD FRONT.
MODELS NOW SHOWING A DRY SLOT ACROSS CENTRAL INDIANA FOR MUCH OF
TUESDAY. THIS SEEMS REASONABLE WITH FIRST SURFACE AND UPPER SYSTEMS
MOVING OFF THE NORTH...AND NEXT UPPER LOW AND SURFACE LOW STILL
ORGANIZING TO THE SOUTH/SOUTHWEST. HOWEVER DO NOT BELIEVE THE VERY
DRY GFS GIVEN THAT ANY WEAK UPPER IMPULSES COULD GENERATE SOME
SHOWERS.
THUS WENT MAINLY CHANCE POPS THROUGH THE DAY TUESDAY ACROSS THE
AREA. KEPT HIGHER POPS EAST DURING THE MORNING TO ACCOUNT FOR RAIN
ALONG THE EXITING SURFACE FRONT.
TUESDAY NIGHT POPS WILL INCREASE ONCE AGAIN AS THE NEXT SYSTEM
APPROACHES FROM THE SOUTH. BY 06Z WENT LIKELY POPS MOST AREAS.
ON WEDNESDAY A SURFACE LOW WILL MOVE THROUGH THE AREA. MODELS STILL
UNCERTAIN ON EXACT PATH...BUT IT SHOULD BE IN THE GENERAL AREA OF
CENTRAL INDIANA TO WESTERN OHIO. WENT HIGH END LIKELY POPS...AND MAY
NEED TO UP THEM TO CATEGORICAL AS WE GET CLOSER.
WITH THE MORE WESTERN TRACKS OF THE MODELS GAINING FAVOR /GFS
ENSEMBLE MEAN AND PARALLEL GFS ARE FARTHER WEST THAN OPERATIONAL GFS
AND ECMWF/ FEEL THAN RAIN WILL BE THE PRIMARY PRECIPITATION TYPE
THROUGH THE DAY WEDNESDAY. WENT WITH CHANCE OF SNOW MIXING IN ACROSS
ROUGHLY THE WEST HALF OF CENTRAL INDIANA IN THE LATE AFTERNOON AS
COLDER AIR STARTS TO WORK IN.
MOST OF THE FORCING WILL BE OFF TO THE EAST WEDNESDAY NIGHT SO WENT
CHANCE POPS. WILL HAVE TO WATCH CLOSELY THOUGH IN CASE DEFORMATION
ZONE OR EVEN A TROWAL BRING BETTER CHANCES. WENT SNOW AS THE
PRECIPITATION TYPE WITH COLDER AIR QUICKLY MOVING IN. AT THE MOMENT
WILL KEEP ANY SNOWFALL AMOUNTS LESS THAN AN INCH.
FOR TEMPERATURES THROUGH THE PERIOD GENERALLY STUCK WITH A BLEND OF
GFS/ECMWF/MOS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 253 AM EST MON DEC 22 2014
STRONG SYSTEM SET TO IMPACT THE REGION CHRISTMAS EVE WILL LIFT INTO
QUEBEC BY EARLY CHRISTMAS MORNING...WILL ANY LEFTOVER LIGHT SNOW
SHOWERS DEPARTING AROUND OR SHORTLY BEFORE DAYBREAK. SURFACE RIDGING
WILL IMMEDIATELY EXPAND INTO THE OHIO VALLEY ON THURSDAY WITH CLOUDS
GRADUALLY DIMINISHING AS WINDS TURN SOUTHERLY. FOCUS SHIFTS ABRUPTLY
TO NEXT SURFACE WAVE EJECTING OUT OF THE CENTRAL PLAINS AS YET
ANOTHER SHARP UPPER TROUGH DIVES INTO THE NORTHERN ROCKIES. OVERALL
MODEL CONSENSUS IS NOT TOO BAD AT THIS POINT WITH RESPECT TO THE
SURFACE LOW TRACK INTO THE WESTERN GREAT LAKES BY FRIDAY NIGHT.
SOUTHERLY FLOW AND WARM ADVECTION AHEAD OF THIS FEATURE WILL BRING
MILDER AIR NORTH WITH ANY PRECIPITATION FALLING AS RAIN INTO FRIDAY
EVENING. COLDER AIR WILL SPILL IN LATE AS A COLD FRONT PASSES
THROUGH THE REGION...WITH PRECIP POSSIBLY MIXING WITH OR CHANGING TO
LIGHT SNOW INTO SATURDAY BEFORE ENDING.
REMAINDER OF THE EXTENDED QUITE A BIT MORE CONVOLUTED AS MODELS
EXHIBITING DIFFERENCES IN HANDLING OF SUBSEQUENT WAVES ALOFT
TRAVERSING THE LOWER 48. THE ECMWF AND GGEM STARTING TO FAVOR
SECONDARY SURFACE WAVE DEVELOPMENT ON THE TRAILING PART OF THE
AFOREMENTIONED COLD FRONT...BRINGING THE FEATURE NORTHEAST OUT OF
THE WESTERN GULF OF MEXICO UP INTO THE OHIO AND TENNESSEE VALLEYS BY
EARLY SUNDAY IN TANDEM WITH THE WAVE ALOFT. NOT SURPRISINGLY...OP
GFS/PARALLEL GFS AND PRETTY MUCH ALL OF THE GFS ENSEMBLE MEMBERS
PAINT A COMPLETELY DIFFERENT PICTURE...WITH ANY SECONDARY WAVE
DEVELOPMENT ON THE FRONT BEING SUPPRESSED ALONG THE GULF COAST WITH
NO UPPER SUPPORT PRESENT.
WILL MAINTAIN A DRY CHILLY FORECAST FOR THE SECOND HALF OF THE
WEEKEND TO MAINTAIN CONTINUITY FROM PREVIOUS FORECASTS...BUT IT WILL
BE INTERESTING TO SEE IF THE GLOBAL MODELS MAINTAIN THIS NEW IDEA OF
BRINGING A SECONDARY WAVE NORTH WITH POTENTIALLY ADDITIONAL
OPPORTUNITIES FOR WINTRY PRECIP SATURDAY NIGHT AND SUNDAY. NOT
ANTICIPATING ANY BETTER MODEL CONSENSUS FOR AT LEAST A FEW MORE
DAYS...ESPECIALLY CONSIDERING THE CHAOTIC MODEL PERFORMANCE
RECENTLY. DEFINITELY SOMETHING TO MONITOR GOING FORWARD.
&&
.AVIATION /DISCUSSION FOR 221200Z TAF ISSUANCE/...
ISSUED AT 922 AM EST MON DEC 22 2014
1423Z UPDATE...PUSHED BACK TIMING FOR MFVR BY AN HOUR FOR A FEW OF
THE SITES. OTHERWISE NO OTHER CHANGES NEEDED AT THIS TIME.
PREVIOUS DISCUSSION FOLLOWS.
DETERIORATING FLYING CONDITIONS THROUGH THE PERIOD WITH RAIN
IMPACTING THE TERMINALS THIS AFTERNOON INTO TONIGHT.
CLOUD DECK HAS QUICKLY ENCOMPASSED THE TERMINALS OVER THE LAST FEW
HOURS. MOISTURE WILL CONTINUE TO INCREASE AHEAD OF A WARM FRONT...
WITH CEILINGS EXPECTED TO SINK INTO MVFR CATEGORY BY MID MORNING.
LIGHT RAIN EXPANDING IN COVERAGE NEAR THE MISSISSIPPI RIVER AND
WILL CONTINUE NORTHEAST OVER THE NEXT FEW HOURS. HRRR KEEPS BULK
OF THE PRECIP THROUGH EARLY AFTERNOON WEST OF THE TERMINALS...WITH
ONLY KHUF AND POSSIBLY KLAF BEING IMPACTED.
AS LOW PRESSURE AND ITS ASSOCIATED WARM FRONT APPROACH THE REGION
LATER THIS AFTERNOON INTO THE EVENING HOWEVER...EXPECT WIDESPREAD
RAIN AND IFR CONDITIONS TO DEVELOP OVER CENTRAL INDIANA. SOUTHEAST
WINDS WILL STEADILY INCREASE TO 10-15KTS BY THIS EVENING...
EVENTUALLY VEERING TO A MORE SOUTHERLY DIRECTION AND BECOMING
GUSTY BY DAYBREAK TUESDAY AS THE WARM FRONT PASSES THROUGH THE
FORECAST AREA. RAIN WILL DECREASE IN COVERAGE AFTER 06Z AS THE
SURFACE LOW LIFTS INTO NORTHERN ILLINOIS...BUT LOW STRATUS WILL
PERSIST AS MODEL SOUNDINGS AND 925/950MB RH PROGS MAINTAIN DEEP
LOW LEVEL MOISTURE BENEATH AN INVERSION.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....RYAN
AVIATION...SMF/RYAN
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
543 AM EST MON DEC 22 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 327 AM EST MON DEC 22 2014
AN UPPER TROUGH AND A COUPLE OF AREAS OF LOW PRESSURE WILL BRING
RAIN TO CENTRAL INDIANA TODAY INTO WEDNESDAY...WITH PERHAPS SOME
SNOW WEDNESDAY NIGHT. ANOTHER SYSTEM WILL BRING ADDITIONAL CHANCES
FOR PRECIPITATION FRIDAY AND SATURDAY. NEAR TO ABOVE AVERAGE
TEMPERATURES THIS WEEK WILL RETURN TO COOLER THAN AVERAGE FOR THE
WEEKEND.
&&
.NEAR TERM.../TODAY/
ISSUED AT 327 AM EST MON DEC 22 2014
ISENTROPIC LIFT WILL INCREASE TODAY AS AN UPPER TROUGH AND SURFACE
WARM FRONT MOVE TOWARD CENTRAL INDIANA. BEST FORCING ARRIVES LATE IN
THE DAY WHEN 850MB WINDS APPROACH 50KT AND AN UPPER JET MOVES CLOSER
TO THE AREA.
ANY PRECIPITATION WILL HAVE TO FIGHT THE DRY LOWER LEVELS OF THE
ATMOSPHERE INITIALLY. SOUTHEAST WINDS AT THE SURFACE WILL AID IN
KEEPING THE LOWER LEVELS DRY. THUS IT WILL TAKE THE ATMOSPHERE A
WHILE TO MOISTEN UP.
GIVEN THE ABOVE...WENT HIGHEST POPS TODAY AT THE END OF THE TODAY
PERIOD. GRADUALLY INCREASED POPS DURING THE DAY. BY LATE DAY WENT
LIKELY POPS FAR WEST...CHANCE CENTRAL...AND SLIGHT CHANCE FAR EAST.
CLOUDS WILL INCREASE/THICKEN THROUGH THE DAY. A BLEND OF MODELS
LOOKS BEST FOR HIGH TEMPERATURES...AND THIS ENDS UP NEAR TO A LITTLE
COOLER THAN MOS SUGGESTS.
&&
.SHORT TERM.../TONIGHT THROUGH WEDNESDAY NIGHT/
ISSUED AT 327 AM EST MON DEC 22 2014
FOCUS IS ON PRECIPITATION CHANCES THROUGH THE PERIOD. THREW OUT THE
NAM AS ITS SOLUTION OF BRINGING A SURFACE LOW NEAR THE APPALACHIANS
LOOKS UNREALISTIC. GFS/ECMWF/CANADIAN MODELS ARE SIMILAR AND LOOK
MORE REASONABLE...SO USED A BLEND OF THEIR SOLUTIONS.
RAIN WILL CONTINUE TO OVERSPREAD CENTRAL INDIANA TONIGHT WITH FIRST
A WARM FRONT THEN A COLD FRONT MOVING THROUGH THE AREA. 850MB JET
WILL PROVIDE GOOD MOISTURE AND FORCING...AND UPPER TROUGH/UPPER JET
WILL BRING ADDITIONAL FORCING. THUS WENT CATEGORICAL POPS ALL AREAS
TONIGHT. LOWERED POPS OVERNIGHT AS SOME DRIER AIR WORKS IN BEHIND
THE COLD FRONT.
MODELS NOW SHOWING A DRY SLOT ACROSS CENTRAL INDIANA FOR MUCH OF
TUESDAY. THIS SEEMS REASONABLE WITH FIRST SURFACE AND UPPER SYSTEMS
MOVING OFF THE NORTH...AND NEXT UPPER LOW AND SURFACE LOW STILL
ORGANIZING TO THE SOUTH/SOUTHWEST. HOWEVER DO NOT BELIEVE THE VERY
DRY GFS GIVEN THAT ANY WEAK UPPER IMPULSES COULD GENERATE SOME
SHOWERS.
THUS WENT MAINLY CHANCE POPS THROUGH THE DAY TUESDAY ACROSS THE
AREA. KEPT HIGHER POPS EAST DURING THE MORNING TO ACCOUNT FOR RAIN
ALONG THE EXITING SURFACE FRONT.
TUESDAY NIGHT POPS WILL INCREASE ONCE AGAIN AS THE NEXT SYSTEM
APPROACHES FROM THE SOUTH. BY 06Z WENT LIKELY POPS MOST AREAS.
ON WEDNESDAY A SURFACE LOW WILL MOVE THROUGH THE AREA. MODELS STILL
UNCERTAIN ON EXACT PATH...BUT IT SHOULD BE IN THE GENERAL AREA OF
CENTRAL INDIANA TO WESTERN OHIO. WENT HIGH END LIKELY POPS...AND MAY
NEED TO UP THEM TO CATEGORICAL AS WE GET CLOSER.
WITH THE MORE WESTERN TRACKS OF THE MODELS GAINING FAVOR /GFS
ENSEMBLE MEAN AND PARALLEL GFS ARE FARTHER WEST THAN OPERATIONAL GFS
AND ECMWF/ FEEL THAN RAIN WILL BE THE PRIMARY PRECIPITATION TYPE
THROUGH THE DAY WEDNESDAY. WENT WITH CHANCE OF SNOW MIXING IN ACROSS
ROUGHLY THE WEST HALF OF CENTRAL INDIANA IN THE LATE AFTERNOON AS
COLDER AIR STARTS TO WORK IN.
MOST OF THE FORCING WILL BE OFF TO THE EAST WEDNESDAY NIGHT SO WENT
CHANCE POPS. WILL HAVE TO WATCH CLOSELY THOUGH IN CASE DEFORMATION
ZONE OR EVEN A TROWAL BRING BETTER CHANCES. WENT SNOW AS THE
PRECIPITATION TYPE WITH COLDER AIR QUICKLY MOVING IN. AT THE MOMENT
WILL KEEP ANY SNOWFALL AMOUNTS LESS THAN AN INCH.
FOR TEMPERATURES THROUGH THE PERIOD GENERALLY STUCK WITH A BLEND OF
GFS/ECMWF/MOS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 253 AM EST MON DEC 22 2014
STRONG SYSTEM SET TO IMPACT THE REGION CHRISTMAS EVE WILL LIFT INTO
QUEBEC BY EARLY CHRISTMAS MORNING...WILL ANY LEFTOVER LIGHT SNOW
SHOWERS DEPARTING AROUND OR SHORTLY BEFORE DAYBREAK. SURFACE RIDGING
WILL IMMEDIATELY EXPAND INTO THE OHIO VALLEY ON THURSDAY WITH CLOUDS
GRADUALLY DIMINISHING AS WINDS TURN SOUTHERLY. FOCUS SHIFTS ABRUPTLY
TO NEXT SURFACE WAVE EJECTING OUT OF THE CENTRAL PLAINS AS YET
ANOTHER SHARP UPPER TROUGH DIVES INTO THE NORTHERN ROCKIES. OVERALL
MODEL CONSENSUS IS NOT TOO BAD AT THIS POINT WITH RESPECT TO THE
SURFACE LOW TRACK INTO THE WESTERN GREAT LAKES BY FRIDAY NIGHT.
SOUTHERLY FLOW AND WARM ADVECTION AHEAD OF THIS FEATURE WILL BRING
MILDER AIR NORTH WITH ANY PRECIPITATION FALLING AS RAIN INTO FRIDAY
EVENING. COLDER AIR WILL SPILL IN LATE AS A COLD FRONT PASSES
THROUGH THE REGION...WITH PRECIP POSSIBLY MIXING WITH OR CHANGING TO
LIGHT SNOW INTO SATURDAY BEFORE ENDING.
REMAINDER OF THE EXTENDED QUITE A BIT MORE CONVOLUTED AS MODELS
EXHIBITING DIFFERENCES IN HANDLING OF SUBSEQUENT WAVES ALOFT
TRAVERSING THE LOWER 48. THE ECMWF AND GGEM STARTING TO FAVOR
SECONDARY SURFACE WAVE DEVELOPMENT ON THE TRAILING PART OF THE
AFOREMENTIONED COLD FRONT...BRINGING THE FEATURE NORTHEAST OUT OF
THE WESTERN GULF OF MEXICO UP INTO THE OHIO AND TENNESSEE VALLEYS BY
EARLY SUNDAY IN TANDEM WITH THE WAVE ALOFT. NOT SURPRISINGLY...OP
GFS/PARALLEL GFS AND PRETTY MUCH ALL OF THE GFS ENSEMBLE MEMBERS
PAINT A COMPLETELY DIFFERENT PICTURE...WITH ANY SECONDARY WAVE
DEVELOPMENT ON THE FRONT BEING SUPPRESSED ALONG THE GULF COAST WITH
NO UPPER SUPPORT PRESENT.
WILL MAINTAIN A DRY CHILLY FORECAST FOR THE SECOND HALF OF THE
WEEKEND TO MAINTAIN CONTINUITY FROM PREVIOUS FORECASTS...BUT IT WILL
BE INTERESTING TO SEE IF THE GLOBAL MODELS MAINTAIN THIS NEW IDEA OF
BRINGING A SECONDARY WAVE NORTH WITH POTENTIALLY ADDITIONAL
OPPORTUNITIES FOR WINTRY PRECIP SATURDAY NIGHT AND SUNDAY. NOT
ANTICIPATING ANY BETTER MODEL CONSENSUS FOR AT LEAST A FEW MORE
DAYS...ESPECIALLY CONSIDERING THE CHAOTIC MODEL PERFORMANCE
RECENTLY. DEFINITELY SOMETHING TO MONITOR GOING FORWARD.
&&
.AVIATION /DISCUSSION FOR 221200Z TAF ISSUANCE/...
ISSUED AT 543 AM EST MON DEC 22 2014
DETERIORATING FLYING CONDITIONS THROUGH THE PERIOD WITH RAIN
IMPACTING THE TERMINALS THIS AFTERNOON INTO TONIGHT.
CLOUD DECK HAS QUICKLY ENCOMPASSED THE TERMINALS OVER THE LAST FEW
HOURS. MOISTURE WILL CONTINUE TO INCREASE AHEAD OF A WARM FRONT...
WITH CEILINGS EXPECTED TO SINK INTO MVFR CATEGORY BY MID MORNING.
LIGHT RAIN EXPANDING IN COVERAGE NEAR THE MISSISSIPPI RIVER AND
WILL CONTINUE NORTHEAST OVER THE NEXT FEW HOURS. HRRR KEEPS BULK
OF THE PRECIP THROUGH EARLY AFTERNOON WEST OF THE TERMINALS...WITH
ONLY KHUF AND POSSIBLY KLAF BEING IMPACTED.
AS LOW PRESSURE AND ITS ASSOCIATED WARM FRONT APPROACH THE REGION
LATER THIS AFTERNOON INTO THE EVENING HOWEVER...EXPECT WIDESPREAD
RAIN AND IFR CONDITIONS TO DEVELOP OVER CENTRAL INDIANA. SOUTHEAST
WINDS WILL STEADILY INCREASE TO 10-15KTS BY THIS EVENING...
EVENTUALLY VEERING TO A MORE SOUTHERLY DIRECTION AND BECOMING
GUSTY BY DAYBREAK TUESDAY AS THE WARM FRONT PASSES THROUGH THE
FORECAST AREA. RAIN WILL DECREASE IN COVERAGE AFTER 06Z AS THE
SURFACE LOW LIFTS INTO NORTHERN ILLINOIS...BUT LOW STRATUS WILL
PERSIST AS MODEL SOUNDINGS AND 925/950MB RH PROGS MAINTAIN DEEP
LOW LEVEL MOISTURE BENEATH AN INVERSION.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....RYAN
AVIATION...RYAN
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
947 PM CST TUE DEC 23 2014
.UPDATE...
ISSUED AT 943 PM CST TUE DEC 23 2014
BAND OF SNOW CONTINUES FROM PORTIONS OF NORTHEAST-CENTRAL-SOUTHWEST
IA WITHIN ZONE OF WEAK ISENTROPIC LIFT ON BACKSIDE OF UPPER TROUGH
AXIS. THIS LIFT DEPICTED WELL ON 295K SFC OF NAM AND RAP MODELS
AND IS SHOWN TO GRADUALLY WEAKEN OVERNIGHT REMAINING MAINLY WEST OF
CWA ALTHOUGH POSSIBLY BRUSHING FAR WEST SECTIONS... ALONG/W OF
IIB-VTI-OOA LINE WITH FLURRIES OR VERY LIGHT SNOW. OTHERWISE...SOME
PATCHY DRIZZLE WAS NOTED ALONG MISSISSIPPI RIVER AHEAD OF FRONT
AND THIS MAY CONTINUE NEXT FEW HOURS BEFORE SHIFTING EAST WITH THE
FRONT... THEN ASIDE FROM FAR WESTERN CWA REST OF THE NIGHT APPEARS
TO BE MAINLY DRY. AS RESULT... HAVE UPDATED TO REMOVE ANY MEASURABLE
POPS REST OF TONIGHT. ALSO...WITH CONSIDERABLE CLOUDS AND FAIRLY
WEAK COLD ADVECTION HAVE NUDGED UP MINS WITH MOST AREAS STAYING AT
OR ABOVE 32F.
AS FOR TOMORROW /CHRISTMAS EVE/ SYSTEM... SOME OF THE LATEST MODEL
GUIDANCE OF RAP...NAM AND GFS MODELS TAKE THE STORM SLIGHTLY
FURTHER EAST AND SUGGEST MAY NOT EVEN SEE FAR EAST BRUSHED BY ANY
SNOW. MAY SEE SOME FLURRIES AND POSSIBLY FEW SNOW SHOWERS IF
SUFFICIENT MOISTURE DEPTH BUT ASIDE FROM BRIEF REDUCTION IN VSBY
(SHOULD THE SNOW SHOWERS OCCUR) NO IMPACTS EXPECTED WITH TEMPS ABOVE
32F. HAVING SAID THAT... ANYONE WITH TRAVEL INTERESTS TO OUR EAST
TOMORROW WILL WANT TO STAY UPDATED AS POSSIBILITY OF IMPACTS TO TRAVEL
FROM WET/SLUSHY ROADS AND LIMITED VISBILITIES AT TIMES.
&&
.SYNOPSIS...
ISSUED AT 312 PM CST TUE DEC 23 2014
SYNOPSIS...AT 3 PM CST..A WEAK COLD FRONT BISECTED THE DVN CWA.
THICK OVERCAST WAS OBSERVED TO THE NW OF THE BOUNDARY WITH TEMPS
IN THE MID TO UPPER 30S. TO THE SE...IN A SOUTHWEST SFC WIND FLOW
SKIES WERE SCT TO BKN AND TEMPS WERE IN THE LOWER TO MIDDLE
40S...AND A LIGHT RAIN SHOWERS WAS LOCATED NEAR IOWA CITY. A
DEVELOPING SFC LOW PRESSURE SYSTEM WILL MOVE NORTHEASTWARD ON
WEDNESDAY AFTN AND NIGHT...BUT WILL REMAIN WELL EAST OF E IOWA AND
W ILLINOIS. THERE IS A CHANCE FOR LIGHT SNOW ACCUMULATIONS ACROSS
THE FAR EASTERN CWA WITH THIS SYSTEM. HOWEVER HIGH TEMPS IN THE
MID 30S SHOULD LIMIT THE OVERALL IMPACT FROM ANY SNOW THAT FALLS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 312 PM CST TUE DEC 23 2014
TONIGHT...AS THE COLD FRONT SLIDES EAST OF THE AREA AFTER MIDNIGHT
SFC WINDS WILL VEER FROM THE SW TO THE NW AND THE STRATUS WILL
OVERSPREAD THE ENTIRE CWA. NAM FORECAST SFC DEWPOINT DEPRESSIONS ARE
NEAR 1-2 F OVERNIGHT BUT NW FLOW WILL LEAD TO SLOWLY DECREASING
MOISTURE THROUGH THE NIGHT SO NOT EXPECTING MUCH FOR FOG. A FEW
LIGHT RAIN/SNOW SHOWERS WILL BE POSSIBLE AS THE 850 MB TROUGH AXIS
SWINGS THROUGH BUT MANY AREAS WILL REMAIN DRY. NO SNOW ACCUMULATION
IS EXPECTED.
WEDNESDAY...PROMINENT LONGWAVE TROUGH ACROSS THE CENTRAL U.S.
DIPPING ALL THE WAY DOWN TO THE GULF OF MEXICO ALONG WITH A
STRENGTHENING JET STREAK ON ITS EASTERN FLANK AND BURGEONING
CONVECTION ACROSS THE SOUTHERN U.S. WILL INDUCE AN AREA OF
CYCLOGENESIS IN THE WESTERN OHIO VALLEY/GREAT LAKES. THE SFC LOW
IS FORECAST TO TRACK FROM N LOUISIANA TO N LOWER MICHIGAN.
MODEL DISCREPANCIES...12.23/12Z NAM AND GFS WERE THE FURTHEST WEST
WITH THE LOW TRACK FROM NE INDIANA TO NE LOWER MICHIGAN AND HAVE
THE GREATEST POTENTIAL FOR A PERIOD OF SNOW IN MY EASTERN CWA. THE
ECMWF AND GEM ARE FURTHER EAST WITH THE TRACK AND BRING VERY LIGHT
SNOW POTENTIAL WITH LESS THAN 0.10 INCHES OF QPF IN MY EASTERN
COUNTIES. THE HI-RES WRF-NMM HAS THE STEADY PRECIP DEFORMATION
BAND AFFECTING EASTERN BUREAU AND ALL OF PUTNAM COUNTY WITH STRONG
700-500 MB FRONTOGENESIS. THE 18Z NAM HAS NOW SHIFTED SLIGHTLY
EAST SO MODELS OVERALL IN FAIRLY GOOD AGREEMENT AT THIS POINT.
CWA IMPACTS...BEST CHANCES FOR ACCUMULATING SNOW WILL BE IN BUREAU
AND PUTNAM COUNTIES. A FEW FACTORS TO CONSIDER ARE THE RELATIVELY
WARM GROUND WITH THE PROLONGED PERIOD OF TEMPS IN THE 40S THE LAST
FEW DAYS AND FORECAST MAX TEMPS ABOVE FREEZING TOMORROW AFTN.
SINCE THERE IS NO COLD AIR IN PLACE...DYNAMIC COOLING IS NECESSARY
FOR SNOW TO OCCUR. BEST FORECAST AT THIS TIME IS FOR PERIOD OF
LIGHT SNOW TO IMPACT THE FAR EAST DURING THE AFTN WITH
ACCUMULATIONS POSSIBLY UP TO AN INCH OR TWO OF WET SNOW WITH SLRS
AT 9:1 OR SLIGHTLY LOWER...AND FLURRIES OR SCT SNOW SHOWERS
POSSIBLE ELSEWHERE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 245 PM CST TUE DEC 23 2014
MAIN FORECAST CONCERN IN THE EXTENDED PERIOD IS THE NEXT SYSTEM
THAT WILL AFFECT THE AREA ON FRIDAY AND INTO SATURDAY MORNING.
THIS SYSTEM LOOKS TO BRING US A CHANCE OF RAIN AND SNOW MIXED IN
FOR FRIDAY NIGHT INTO SATURDAY.
CHRISTMAS DAY IS A DRY DAY BETWEEN TWO STORM SYSTEMS. UNFORTUNATELY
AT THIS TIME...IT LOOKS LIKE WE WILL HAVE A BROWN CHRISTMAS AND IT
DOES NOT LOOK LIKE WE WILL HAVE ANY APPRECIABLE SNOW IN THE
EXTENDED. WE COULD SEE THE SUN LATER IN THE DAY ON CHRISTMAS EVE.
USED CONSRAW AS A STARTING POINT FOR TEMPERATURES SINCE BOI VERIFY
SUGGESTED IT HAS VERIFIED THE BEST RECENTLY.
FRIDAY...WARM AIR RETURNS TO THE AREA AS A LOW PRESSURE SYSTEM
PASSES TO OUR NORTH. TEMPERATURES SHOULD BE IN THE HIGH 40S. CLOUDS
RETURN LATER IN THE DAY ON FRIDAY AS ANOTHER STORM SYSTEM MAKES ITS
WAY INTO THE AREA. MODELS DIFFER ON THE TIMING OF PRECIP. THE GFS
HAS PRECIP ENTER THE CWA BEFORE 00Z SATURDAY. THE GFS APPEARS TO BE
FASTER THAN ALL OF THE MODELS...THIS IS THE CASE IN RESPECT TO THE
GEFS AS WELL. THE GEM AND ECMWF ARE CLOSER TO THE GEFS MEANS. SO
DECIDED TO EXCLUDE THE GFS FORECAST FOR PRECIP DURING THIS TIME.
LOOKS LIKE PRECIP MAKES ITS WAY IN AS A COLD FRONT APPROACHES THE
AREA. H92 TEMPS AND MODEL SOUNDINGS FROM THE GFS SUGGEST SNOW AT 03Z
ACROSS THE AREA...HOWEVER THE ECMWF WHICH HAS A MORE REASONABLE
SOLUTION SUGGESTS RAIN ACROSS EASTERN PORTIONS OF THE CWA FROM 00Z
TO 03Z WITH A RASN LINE MOVING EAST THROUGH THAT TIME. BY 12Z MOST
OF THE PRECIP WILL BE SNOW...WITH A FEW AREAS IN FAR EASTERN ZONES
STILL A RASN MIX.
LOOKING TOWARDS THE END OF THE EXTENDED PERIOD. A POLAR AIRMASS IS
FORECAST TO OCCUPY THE AREA TOWARDS NEW YEARS EVE. MODELS AGREE
THAT FLOW WILL BE OUT OF THE NW...SO TEMPS SHOULD BE COOLER THE
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 543 PM CST TUE DEC 23 2014
MLI AND BRL WILL BEGIN THE TAF CYCLE WITH VFR CONDITIONS BUT EXPECTED
TO LOWER INTO MVFR THIS EVENING WITH PASSAGE OF FRONTAL BOUNDARY...WITH
WINDS SHIFTING TO NORTHWEST AROUND 10 KTS. CID AND DBQ WILL REMAIN
MVFR TO IFR TONIGHT WITH SPOTTY DRIZZLE OR VERY LIGHT RAIN
TRANSITIONING TO FEW FLURRIES. ON WEDNESDAY...A STORM SYSTEM WILL
INTENSITY WHILE LIFTING NORTHWARD FROM THE LOWER MISSISSIPPI VLY
INTO THE GREAT LAKES. THE BULK OF ANY RAIN OR SNOW WILL REMAIN
EAST OF THE TERMINALS...BUT MAY SEE FEW FLURRIES OR PATCHY DRIZZLE
AT TIMES DURING THE DAY WITH MAINLY MVFR TO AREAS OF IFR CONDITIONS.
NORTHWEST WINDS WILL BECOME GUSTY AT TIMES AT 10-20+ KTS ON WEDNESDAY.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...05
SYNOPSIS...UTTECH
SHORT TERM...UTTECH
LONG TERM...GIBBS
AVIATION...05
AREA FORECAST DISCUSSION
NWS DES MOINES IA
553 PM CST TUE DEC 23 2014
.SHORT TERM /TONIGHT/...
ISSUED AT 313 PM CST TUE DEC 23 2014
PRECIP TRENDS WILL REMAIN THE PRIMARY FOCUS AGAIN TONIGHT. LIGHT
SNOW CONTINUES TO DRIFT NE-SW ACROSS THE NW HALF OF IA DRIVEN
MAINLY BY MID LEVEL KINEMATIC FORCING WITH WEAK DEFORMATION AND
DIFFERENTIAL POSITIVE VORTICITY ADVECTION NORTH OF IA PV ANOMALY
NOTED IN RAP ANALYSIS AND SUGGESTED BY PIVOT POINT IN WATER VAPOR
IMAGERY. THERE IS LITTLE THERMODYNAMIC COMPONENT AT THIS POINT.
PRECIP IS QUITE LIGHT WITH WEAK REFLECTIVITY...EVEN IN LONG
PULSE/VCP 31. WEBCAMS SHOW CURRENT VISIBILITY RESTRICTIONS ARE AS
MUCH DUE TO FOG AS SNOW WITH LITTLE SNOW NOTED. THIS WEAK FORCING
WILL REMAIN ESSENTIALLY STEADY STATE AS IT DRIFTS SLOWLY SOUTH AND
EAST THROUGH THE NIGHT BEFORE THE NEXT SHORT WAVE/PV ANOMALY
ROUNDS THE BASE OF THE TROUGH AND RE-ENERGIZES SYSTEM AGAIN TO OUR
SOUTH AND EAST TOWARD 12Z. SE FRINGE OF PRECIP SHIELD WILL BE A
RAIN/SNOW MIX WITH RAIN/SNOW LINE DRIFTING SE. ONLY LIGHT QPF
AMOUNTS AND TEMPERED SNOW RATIOS WILL RESULT ANY ADDITIONAL ACCUMS
BEING UNDER AN INCH AND MAINLY ON GRASSY OR ELEVATED SURFACES.
ROAD TEMPS REMAIN WET AND 35F PLUS SO MUCH OF SNOW WILL MELT ON
ROADS. MID LEVEL MOISTURE WILL BE LACKING SE WITH LITTLE ICE
INTRODUCTION SO PRECIP WILL GENERALLY REMAIN LIQUID/DRIZZLE SOUTH
AND EAST OF DES MOINES.
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
ISSUED AT 313 PM CST TUE DEC 23 2014
THE LONG TERM PORTION OF THE FCST PD WILL BE CHARACTERIZED BY
MINIMAL PRECIPITATION...ALONG WITH ABOVE NORMAL TEMPERATURES LATE
THIS WEEK FOLLOWED BY TEMPERATURES GOING BELOW NORMAL BEGINNING
THIS WEEKEND AND CONTINUING INTO NEXT WEEK.
MODELS IN GOOD AGREEMENT WITH THE CENTRAL CONUS SHORTWAVE ENERGY
DEVELOPING A SFC LOW ACROSS THE SOUTHERN U.S. TONIGHT...BRINGING
IT NORTH-NORTHEAST INTO THE EASTERN GREAT LAKES AND DEEPENING BY
THURSDAY. GREATEST SYNOPTIC FORCING AND MOISTURE WILL REMAIN TO
THE EAST OF THE CWA. MODELS SHOWING REMNANT AREA OF WEAK LIFT AND
MOISTURE IN E/SE CWA THRU WED MORNING...SO HAVE KEPT CHC/SLIGHT
CHANCE POPS THERE. PCPN IS EXPECTED TO BE LIGHT.
ATTENTION THEN TURNS TO THE NEXT WX SYSTEM TO AFFECT OUR REGION.
CENTRAL U.S. SHORTWAVE LIFTS OUT AND ANOTHER SHORTWAVE ENTERS THE
WESTERN U.S. BY THURSDAY. MODELS BEGIN DIVERGING ON THE SPEED AND
STRENGTH OF THIS SHORTWAVE ONCE IT ARRIVES. GFS PRESENTS A FASTER
AND WEAKER SOLUTION...WITH THE ECMWF HOLDING THE ENERGY BACK FOR
LONGER. THE DIVERGING SOLUTIONS IMPACT SFC FEATURES AS WELL...WITH
THE GFS BRINGING A STRONGER SFC SYSTEM THROUGH OUR REGION AND
FASTER VS. THE ECMWF. HAVE TRENDED SLOWER THAN THE GFS GIVEN ITS
RECENT PERFORMANCE...BRINGING -SN INTO THE CWA BEGINNING 12Z FRI.
PRIOR TO THE PRECIP/S ARRIVAL...THOUGH...STRONG WAA WILL PUSH
THURSDAY/S MAXES INTO THE MIDDLE 30S AND 40S. ATTM THE BULK OF THE
PRECIP IS EXPECTED TO REMAIN NW OF THE CWA...WITH BEST COMBINATION
OF FORCING AND MOISTURE MOVING ACROSS THE CWA FRI AFTN AND FRIDAY
NIGHT. ALTHOUGH POPS ARE RELATIVELY LOW...THERE IS THE POTENTIAL
FOR A BRIEF PERIOD OF LIFT TO COINCIDE WITH ELEVATED RH LEVELS
WITHIN THE DGZ ESPECIALLY ACROSS NW IOWA.
MODEL SOLUTIONS DIVERGE FURTHER WITH TIME INTO THE WEEKEND SO
FORECAST CONFIDENCE DECREASES. GFS KEEPS OUR REGION IN CYCLONIC
FLOW WITH WEAK SHORTWAVES WHILE THE ECMWF BRINGS MORE FOCUSED
SHORTWAVE ENERGY THROUGH OUR REGION MONDAY. HAVE TENDED TOWARD THE
ECMWF AND HAVE SLIGHT CHANCE POPS FOR THIS TIME PD. LITTLE IF ANY
SNOWFALL ACCUMULATIONS ARE AGAIN EXPECTED GIVEN THE BEST FORCING
BEING OUT OF PHASE WITH ELEVATED MOISTURE LEVELS. TEMPERATURES
WILL BEGIN A DOWNWARD TEND AS NORTHWEST FLOW ALOFT PREVAILS.
&&
.AVIATION...24/00Z
ISSUED AT 543 PM CST TUE DEC 23 2014
COLD FRONT HAS NEARLY EXITED THE AREA NOW AND WILL PASS THROUGH
THE KOTM AREA IN THE NEXT HOUR OR SO. COLDER AIR WILL GRADUALLY
TURN LIGHT RAIN TO LIGHT SNOW WITH MVFR TO LOCAL IFR VSBY
CONDITIONS EXPECTED. CIGS WILL REMAIN AOB 1 THOUSAND THROUGH THE
NIGHT WITH SOME IMPROVEMENT INTO THE MVFR CATEGORY ON WEDNESDAY.
OUTLOOK...IMPROVING CONDITIONS EXPECTED TUE NIGHT INTO WED WITH
VFR CONDITIONS EXPECTED INTO CHRISTMAS DAY BEFORE NEXT SYSTEM
MOVES IN LATE FRI.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...ZOGG
AVIATION...MS DEC 14
AREA FORECAST DISCUSSION
NWS TOPEKA KS
512 AM CST Mon Dec 22 2014
...AVIATION UPDATE...
.SHORT TERM...(Today and Tonight)
Issued at 240 AM CST MON DEC 22 2014
Water vapor imagery continues to show a broad upper level trough
over the central U.S. at 09Z. Profiler and airplane reports show a
150+ KT jet streak on the back side of the upper trough from the
Pacific northwest into the central Rockies. Meanwhile at the
surface, an area of low pressure was forming over the northern
plains with a trough axis extending south through western and
central KS.
For today the surface trough axis/front is expected to gradually
move east across the area as energy on the back side of the upper
trough causes a closed upper level low to develop over the central
plains. As it does, models prog a decent shortwave to swing through
northern KS providing forcing for showers along the trough axis. All
of the models seem to be in agreement on this, and the only real
difference in the solutions is the GFS seems to be the deepest with
the upper low and the surface reflection. This may explain why the
GFS is a little more aggressive with the surface winds this
afternoon on account of having the strongest pressure gradient. In
any case, it looks like the strongest vertical motion from the
shortwave moves overhead during the late morning and early
afternoon. With this in mind, have the highest pops along and east
of the expected trough axis location through the early afternoon.
Considered inserting a mention of thunder to the forecast as the
shortwave rotates through the area. The NAM and GFS show a small
window where mid level lapse rates steepen to around 8 C/km. But
since instability remains very modest due to the cool and moist
nature of the airmass, have left the forecast all rain. However I
would not be surprised if there were a couple rumbles of thunder
early in the afternoon across east central KS. Cloud cover and
precip are expected to keep temps from warming much and have highs
in the mid 40s, or only several degrees warmer than current
readings.
Tonight should see surface winds become westerly as a surface low
propagates into the MS river valley. This should usher in some
relatively dry air to the forecast area. Unfortunately the closed
upper low is expected to remain over the MO river valley with the
potential for upper level deformation and moisture wrapping around
the back side of the upper low back into northern KS. The GFS seems
to be the more bullish solution with its QPF overnight and am a
little concerned this may be due to it developing a deeper system
then other solutions. Nevertheless have held onto POPs tonight
showing the potential for precip. Models show mostly subsidence
developing this evening across east central KS, so think any chance
for precip overnight will be across northern KS and along the NEB
boarder. There looks to be enough cold air moving in that the precip
could be in the form of snow after midnight as well. At this point
with temps forecast to be in the lower and mid 30s overnight and
models showing the better mid level frontogenesis setting up over
southeast NEB, think snow may only amount to a dusting before 12Z.
.LONG TERM...(Tuesday through Sunday)
Issued at 240 AM CST MON DEC 22 2014
A complicated forecast in the mid term as minor changes between
model runs create major changes in the location of optimal lift and
consequential precipitation, especially from Tuesday through
Wednesday morning. Nevertheless, it does appear model guidance in
showing better consistency with an upper jet streak within the
northwest flow diving southeast towards the southern plains. As this
occurs, embedded lift enhances behind the departing upper low.
Better confidence in this system lead to higher precip chances for
the CWA Tuesday as the wave and cold front move through. Still
remains some uncertainty in strength of this wave. Cross sections
and previous runs reveal the GFS to be an outlier with the amount of
forcing and generous amounts of QPF Tuesday afternoon. Leaned closer
to the ECMWF and NAM solutions as ensemble solutions shows similar
characteristics with the evolution. As precipitation develops along
and behind the boundary, temps will fall close to or just above the
freezing mark. A mix of rain and snow is possible, transitioning to
all snow by early evening, and gradually exiting east central KS
Wednesday morning. At this time do not see areas of strong,
persistent lift and instability to indicate banding precip. Snow
ratios averaged at 12:1 lend to total snowfall accumulations near or
less than an inch by Wednesday morning. Will continue to monitor
trends in the upcoming days as this system has the potential to
impact travel.
For Christmas Eve, southerly winds increase as a lee surface trough
builds, advecting warm air back into the CWA through Christmas Day.
Dry air advection slowly pushes east Wednesday afternoon, as north
central areas may break out into mostly sunny skies. Highs recover
into the upper 30s with overnight lows in the upper 20s. Southerly
winds increase Christmas Day as a slow moving upper trough enters
over the Rockies. Skies become mostly sunny for all of northeast
Kansas as increased WAA boosts highs in the upper 40s. Bulk of the
system and associated QPF passes to the north of the CWA Thursday
evening and Friday. Still could not rule out very light snow
impacting north central areas, otherwise no impacts are seen in
terms of precip. Another cold front cools highs back into the 30s
for the weekend as dry high pressure takes control of the region.
&&
.AVIATION...(For the 12Z TAFs through 12Z Tuesday Morning)
Issued at 511 AM CST MON DEC 22 2014
IFR CIGS are likely to persist until the surface trough axis
passes through the terminals and winds shift to the west. This
should bring in relatively dry air and an end to the light rain.
Once the trough axis passes, models show the boundary layer
moisture mixing out leading to a greater potential for VFR
conditions. There are some timing issues between the NAM and RAP
with when low clouds may mix out. For now leaned a little closer
to the quicker RAP since this lines up well with the FROPA and is
supported somewhat by the HRRR.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...Bowen
AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS JACKSON KY
813 PM EST TUE DEC 23 2014
.UPDATE...
ISSUED AT 618 PM EST TUE DEC 23 2014
WIDESPREAD PRECIP HAS OCCURRED MOST OF THE FORECAST AREA...WITH THE
EXCEPTION OF THE FAR EAST. RAIN WILL CONTINUE AND SHOULD EVENTUALLY
AFFECT EVEN THE EASTERN PART OF THE AREA TONIGHT. PREVIOUS FORECAST
OF CATEGORICAL POPS STILL LOOKS ON TRACK. HAVE UPDATED TEMPS BASED ON
LATEST OBS AND MODEL DATA...BUT OVERALL THE CHANGES WERE MINIMAL.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 353 PM EST TUE DEC 23 2014
THIS AFTERNOON SHOWERS AND THUNDERSTORMS ARE SPREADING ACROSS
PORTIONS OF EASTERN KY. WSR-88D SHOWING BEST CONCENTRATION OF SHOWERS
AND THUNDERSTORMS GENERALLY ALONG AND JUST EAST OF THE WESTERN CWA
BORDER. SHOWERS HAVE BEEN MOVING NE ALONG THIS AREA WITH SOME AREAS
SEEING AROUND A QUARTER OF A INCH WITH HIGHER AMTS POSSIBLE IN
HEAVIER STORMS. HRRR GUIDANCE SEEMS TO HAVE A DECENT HANDLE ON THESE
BANDS OF SHOWERS AND THUNDERSTORMS AND HAS THESE BANDS ACROSS
PORTIONS OF THE TN VALLEY PROGRESSING NORTH ACROSS EASTERN KY THIS
EVENING INTO TONIGHT. 18Z SURFACE ANALYSIS SHOWS LOW PRESSURE
CONTINUING TO DEVELOP ALONG THE LA COAST LINE THIS AFTERNOON. THIS
AREA OF LOW PRESSURE IS EXPECTED TO CONTINUE TO MOVE NORTH AND EAST
OVERNIGHT INTO WEDNESDAY. THIS WILL CONTINUE TO SPREAD RAIN ACROSS
THE REGION. THIS SURFACE LOW WILL ALSO BRING A STRONG COLD FRONT
ACROSS EASTERN KY TOMORROW AFTERNOON THIS WILL PROVIDE GOOD LIFTING
MECHANISM FOR SHOWERS AND THUNDERSTORMS WITH GUSTY WINDS POSSIBLE.
BEHIND THIS FRONT WOULD EXPECT THERE TO CONTINUE TO BE GUSTY WINDS
PARTICULARLY ACROSS THE HIGHER TERRAIN AND NW PORTIONS OF THE CWA.
MOVING INTO WEDNESDAY NIGHT LOW PRESSURE IS FORECAST TO MOVE NORTH
INTO THE GREAT LAKES REGION AND WE WILL QUICKLY GET INTO THE DRY
SLOT. THEREFORE MOISTURE DOES GET CUTOFF AND LOOKING AT FORECAST
SOUNDINGS THIS WOULD LEAD TO LITTLE IF ANY ICE ALOFT. DID OPT TO KEEP
A SLIGHT CHANCE OF RAIN MIXED WITH SNOW AND MAYBE SOME DRIZZLE ACROSS
THE HIGHER TERRAIN...HOWEVER CONFIDENCE IN ANY SNOW CONTINUES TO
DECREASE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 429 PM EST TUE DEC 23 2014
THE MODELS ARE GENERALLY IN GOOD AGREEMENT WITH AN AMPLIFIED LONG
WAVE PATTERN TO CONTINUE THROUGH THE PERIOD ACROSS THE CONUS. MODEL
DIFFERENCES CONTINUE HOWEVER TOWARDS THE LATTER HALF OF THE
PERIOD...AND HAVE SIDED MORE WITH THE ECMWF/CANADIAN SOLUTION GIVEN
THE OVERALL BETTER CONTINUITY.
DEEPER TROUGHING WILL BE MOVING OFF TO THE EAST ON THURSDAY...WITH
ANY LIGHT PRECIPITATION COMING TO AN END ACROSS EASTERN KENTUCKY BY
THE MORNING HOURS. DRY WEATHER WILL RETURN FROM THURSDAY AFTERNOON
THROUGH EARLY SATURDAY MORNING...AS RIDGING TAKES HOLD ACROSS THE
OHIO AND TENNESSEE VALLEYS. MEANWHILE...TROUGHING WILL BE REASSERT
ITSELF ACROSS THE ROCKIES...WITH A COLD FRONT MOVING INTO THE AREA
FOR THE WEEKEND.
THE GFS REMAINS PROGRESSIVE WITH THIS BOUNDARY...WHILE THE
ECMWF/CANADIAN ARE SLOWER AND ALLOW FOR MORE SOUTHERN STREAM
INTERACTION...PROLONGING THE PRECIPITATION CHANCES ALL THE WAY INTO
EARLY NEXT WEEK. AGAIN...AM INCLINED TO LEAN TOWARDS THE
ECMWF/CANADIAN SOLUTION AS THE GFS HAS TRENDED MORE AMPLIFIED WITH
THE UPPER LEVEL PATTERN FROM 24 HOURS AGO. AS SUCH...HAVE FOLLOWED
SUIT WITH THE GIVEN BLENDED GUIDANCE AND ALLOWED FOR LIKELY POPS
BY SUNDAY...AND THEN LOWER CHANCES INTO EARLY NEXT UNTIL SOME OF THE
DETAILS CAN BE IRONED OUT. THE FORECAST TEMPERATURE PROFILES SUPPORT
MORE RAIN THEN SNOW THROUGH WEEKEND...AND THEN PERHAPS A SNOWIER
FINISH AS WE HEAD INTO TUESDAY DEPENDING HOW MUCH COLDER AIR ACTUALLY
MAKES IT IN.
FOR TEMPERATURES...GENERALLY ABOVE NORMAL READINGS LOOK ON TAP
THROUGH THE WEEKEND...WITH NEAR TO COOLER THAN NORMAL VALUES BY EARLY
NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 713 PM EST TUE DEC 23 2014
ALTHOUGH RAIN WAS FALLING AT MOST LOCATIONS...CONDITIONS WERE MAINLY
VFR OVER ALL BUT THE SW AND FAR WESTERN PORTIONS OF THE JKL FORECAST
AREA AT THE START OF THE PERIOD...WITH DOWNSLOPE FLOW FROM THE SOUTH
SOUTHEAST HELPING TO MITIGATE LOW CLOUDS AND FOG. MVFR VISIBILITY WAS
COMMON FROM MIDDLESBORO AND LONDON WESTWARD. ALTHOUGH SOME
FLUCTUATIONS CAN BE EXPECTED TONIGHT...THIS GENERAL SCENARIO SHOULD
CONTINUE. DURING THE DAY ON WEDNESDAY A COLD FRONT WILL MOVE IN FROM
THE WEST AND BRING A POTENTIAL INCREASE IN SHOWER INTENSITY BEFORE IT
PASSES...WITH A RISK OF THUNDERSTORMS TOO. AS THE FRONT PASSES...
WINDS WILL VEER TOWARD THE SW AND THE DOWNSLOPE COMPONENT WILL BE
LOST. AS THIS HAPPENS...CEILINGS SHOULD DROP TO MVFR AND IFR.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...DJ
LONG TERM...GEOGERIAN
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
618 PM EST TUE DEC 23 2014
.UPDATE...
ISSUED AT 618 PM EST TUE DEC 23 2014
WIDESPREAD PRECIP HAS OCCURRED MOST OF THE FORECAST AREA...WITH THE
EXCEPTION OF THE FAR EAST. RAIN WILL CONTINUE AND SHOULD EVENTUALLY
AFFECT EVEN THE EASTERN PART OF THE AREA TONIGHT. PREVIOUS FORECAST
OF CATEGORICAL POPS STILL LOOK ON TRACK. HAVE UPDATED TEMPS BASED ON
LATEST OBS AND MODEL DATA...BUT OVERALL THE CHANGES WERE MINIMAL.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 353 PM EST TUE DEC 23 2014
THIS AFTERNOON SHOWERS AND THUNDERSTORMS ARE SPREADING ACROSS
PORTIONS OF EASTERN KY. WSR-88D SHOWING BEST CONCENTRATION OF SHOWERS
AND THUNDERSTORMS GENERALLY ALONG AND JUST EAST OF THE WESTERN CWA
BORDER. SHOWERS HAVE BEEN MOVING NE ALONG THIS AREA WITH SOME AREAS
SEEING AROUND A QUARTER OF A INCH WITH HIGHER AMTS POSSIBLE IN
HEAVIER STORMS. HRRR GUIDANCE SEEMS TO HAVE A DECENT HANDLE ON THESE
BANDS OF SHOWERS AND THUNDERSTORMS AND HAS THESE BANDS ACROSS
PORTIONS OF THE TN VALLEY PROGRESSING NORTH ACROSS EASTERN KY THIS
EVENING INTO TONIGHT. 18Z SURFACE ANALYSIS SHOWS LOW PRESSURE
CONTINUING TO DEVELOP ALONG THE LA COAST LINE THIS AFTERNOON. THIS
AREA OF LOW PRESSURE IS EXPECTED TO CONTINUE TO MOVE NORTH AND EAST
OVERNIGHT INTO WEDNESDAY. THIS WILL CONTINUE TO SPREAD RAIN ACROSS
THE REGION. THIS SURFACE LOW WILL ALSO BRING A STRONG COLD FRONT
ACROSS EASTERN KY TOMORROW AFTERNOON THIS WILL PROVIDE GOOD LIFTING
MECHANISM FOR SHOWERS AND THUNDERSTORMS WITH GUSTY WINDS POSSIBLE.
BEHIND THIS FRONT WOULD EXPECT THERE TO CONTINUE TO BE GUSTY WINDS
PARTICULARLY ACROSS THE HIGHER TERRAIN AND NW PORTIONS OF THE CWA.
MOVING INTO WEDNESDAY NIGHT LOW PRESSURE IS FORECAST TO MOVE NORTH
INTO THE GREAT LAKES REGION AND WE WILL QUICKLY GET INTO THE DRY
SLOT. THEREFORE MOISTURE DOES GET CUTOFF AND LOOKING AT FORECAST
SOUNDINGS THIS WOULD LEAD TO LITTLE IF ANY ICE ALOFT. DID OPT TO KEEP
A SLIGHT CHANCE OF RAIN MIXED WITH SNOW AND MAYBE SOME DRIZZLE ACROSS
THE HIGHER TERRAIN...HOWEVER CONFIDENCE IN ANY SNOW CONTINUES TO
DECREASE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 429 PM EST TUE DEC 23 2014
THE MODELS ARE GENERALLY IN GOOD AGREEMENT WITH AN AMPLIFIED LONG
WAVE PATTERN TO CONTINUE THROUGH THE PERIOD ACROSS THE CONUS. MODEL
DIFFERENCES CONTINUE HOWEVER TOWARDS THE LATTER HALF OF THE
PERIOD...AND HAVE SIDED MORE WITH THE ECMWF/CANADIAN SOLUTION GIVEN
THE OVERALL BETTER CONTINUITY.
DEEPER TROUGHING WILL BE MOVING OFF TO THE EAST ON THURSDAY...WITH
ANY LIGHT PRECIPITATION COMING TO AN END ACROSS EASTERN KENTUCKY BY
THE MORNING HOURS. DRY WEATHER WILL RETURN FROM THURSDAY AFTERNOON
THROUGH EARLY SATURDAY MORNING...AS RIDGING TAKES HOLD ACROSS THE
OHIO AND TENNESSEE VALLEYS. MEANWHILE...TROUGHING WILL BE REASSERT
ITSELF ACROSS THE ROCKIES...WITH A COLD FRONT MOVING INTO THE AREA
FOR THE WEEKEND.
THE GFS REMAINS PROGRESSIVE WITH THIS BOUNDARY...WHILE THE
ECMWF/CANADIAN ARE SLOWER AND ALLOW FOR MORE SOUTHERN STREAM
INTERACTION...PROLONGING THE PRECIPITATION CHANCES ALL THE WAY INTO
EARLY NEXT WEEK. AGAIN...AM INCLINED TO LEAN TOWARDS THE
ECMWF/CANADIAN SOLUTION AS THE GFS HAS TRENDED MORE AMPLIFIED WITH
THE UPPER LEVEL PATTERN FROM 24 HOURS AGO. AS SUCH...HAVE FOLLOWED
SUIT WITH THE GIVEN BLENDED GUIDANCE AND ALLOWED FOR LIKELY POPS
BY SUNDAY...AND THEN LOWER CHANCES INTO EARLY NEXT UNTIL SOME OF THE
DETAILS CAN BE IRONED OUT. THE FORECAST TEMPERATURE PROFILES SUPPORT
MORE RAIN THEN SNOW THROUGH WEEKEND...AND THEN PERHAPS A SNOWIER
FINISH AS WE HEAD INTO TUESDAY DEPENDING HOW MUCH COLDER AIR ACTUALLY
MAKES IT IN.
FOR TEMPERATURES...GENERALLY ABOVE NORMAL READINGS LOOK ON TAP
THROUGH THE WEEKEND...WITH NEAR TO COOLER THAN NORMAL VALUES BY EARLY
NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 100 PM EST TUE DEC 23 2014
THIS AFTERNOON MOST SPOTS ARE DRY...HOWEVER SHOWERS AND EVEN A FEW
THUNDERSTORMS ARE MOVING NE OUT OF MIDDLE TN. THESE SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO SLOWLY PROGRESS NE OVER THE NEXT FEW
HOURS AND AFFECT SME AND LOZ FIRST. THESE SHOWERS AND THUNDERSTORMS
WILL CONTINUE TO SPREAD ACROSS THE REGION THROUGH THE DAY INTO THE
OVERNIGHT. MOST AREAS THIS AFTERNOON HAVE BEEN BETWEEN VFR/MVFR CIGS
AND THIS WILL TREND TOWARD MVFR AND EVEN CLOSER TO IFR OVER MUCH OF
THE TAF PERIOD AS WE SEE MULTIPLE ROUNDS OF SHOWERS AND SLIGHT CHANCE
OF THUNDERSTORMS. HEAVIER SHOWERS COULD ALSO BRIEFLY REDUCE VIS TO
NEAR IFR CONDITIONS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...DJ
LONG TERM...GEOGERIAN
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
845 PM EST TUE DEC 23 2014
.SYNOPSIS...
LOW PRESSURE OVER THE GULF STATES AND AN ASSOCIATED WARM FRONT
WILL TRACK NORTH OVERNIGHT. A COLD FRONT OVER THE CENTRAL PART OF
THE U.S. WILL TRACK EAST AND REACH THE MID ATLANTIC WEDNESDAY
NIGHT. BREEZY CONDITIONS WILL FOLLOW THE FRONT THURSDAY. HIGH
PRESSURE WILL BUILD INTO THE REGION TO CLOSE OUT THE WEEK.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
DENSE FOG ADVSRY RMNS IN EFFECT ACROSS CENTRAL AND LWR SRN MD...AS
WELL AS WRN LOUDOUN UNTIL 1 AM.
QUITE AN INTERESTING WX PATTERN FOR 12/23. PCPN IS MARCHING INTO
THE MID ATLC...AND IT`S NOT OF THE WINTRY VARIETY. MDT RAFL CAN BE
SEEN ON RGNL RDR OVR NC MOVG N. HRRR HAS IT MOVG INTO THE CENTRAL
SHEN VLLY ARND 04Z...DC ARND 06Z...MASON-DIXON LN BY 09Z. THIS
SHOULD CAUSE LO LVL MIXING...AND THE VSBY TO SHOW SOME IMPVRMNT.
ALL RAIN AND NO CONVECTIVE EXPECTED OVERNIGHT...AS THE RAIN
BATCHES MAKE THEIR WAY NORTH AND ENCOUNTER THE EDGE OF THE CAD
WEDGE. LOCALLY HEAVY EMBEDDED SHOWERS POSSIBLE AT TIMES...ESPEC
ACROSS THE I-95 CORRIDOR AND EAST W/ SOME OF THE ACTIVITY
ORIGINATING AS DEEP CONVECTION WELL TO THE SOUTH.
WEDNESDAY...
BATCHES OF LIGHT/MODERATE RAIN WILL CONTINUE TO SPREAD FROM SW-TO-NE
ACROSS THE AREA...AIDED BY A STRENGTHENING AND POTENT LOW LEVEL JET
MAX. GLOBAL MODELS AND EVEN NEAR-TERM DERIVATIVES ARE IN GOOD
AGREEMENT ON THE INITIAL PHASES OF THE INCOMING STORM SYSTEM. A
COUPLE OF KEY FEATURES THAT HAVE HAD MANY DIFFERENT LOOKS AND
EFFECTS IN THESE RECENT RUNS ARE GRADUALLY BEING RESOLVED. AN
INTENSE SFC LOW WILL BE THE MAIN FEATURE OUT OF ALL THIS ENERGY
INTERACTION IN THE UPPER LEVELS OVER THE ERN HALF OF THE CONUS. THE
LOW WILL ORIGINATE DOWN OVER THE LA GULF COAST AND MAKE A PATH
STRAIGHT TOWARD THE UPPER MIDWEST/GREAT LAKES FROM LATE TODAY INTO
LATE WED EVE.
THE WARM FRONT OUT AHEAD OF THE SFC LOW WILL HAVE PASSED OVER THE
AREA BY EARLY WED MRNG...ALLOWING WARMER THAN AVG TEMPS TO FOLLOW UP
THE ERN SEABOARD. WHILE RAINING FOR A BETTER PART OF THE DAY...WE
WILL STILL SEE TEMPS CLIMB WELL INTO THE 50S...W/ SOME L60S
APPEARING OVER THE SERN SECTIONS OF THE CWA WED AFTN. TOTAL QPF
RANGES FOR THE 24-30 HR RAIN EVENT ARE EXPECTED TO BE IN THE 1-1.5"
RANGE ALONG AND E OF I-95...TAPERING OFF TO ABOUT 0.5-1.0 FROM THE
PIEDMONT WEST TO THE MTNS. ANOMALOUSLY HIGH PWATS WILL BE ASSOCIATED
W/ THIS SYSTEM CLOSE TO THE COAST...AS THE CONVECTIVE AND MODIFIED
TROPICAL CHARACTERISTICS CARRY AMPLE MOISTURE UP THE COAST.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
CDFNT WL BE ON THE WRN EDGE OF CWFA AT START OF PD...AND SHUD BE
MARCHING ACRS AREA THRU THE EVNG INTO THE ELY OVNGT HRS. THIS TIMING
HASNT CHGD MUCH PAST CPL CYCLES...PERHAPS A PINCH FASTER THAN YDA.
FNT WL BE MARKED BY STRONG THERMAL GRADIENT AND BE W/IN ZONE OF DP
SLY FLOW AHD OF AMPLIFIED H5 TROF AXIS. THEREFORE...THERE WL BE
PLENTY OF WARM MOIST AIR TO BE TRANSPORTED NWD...W/ UPGLIDE STILL
PRESENT FOR ADDED LIFT.
AHD OF FNT...AMS UNCHARACTERISTICALLY WARM AND UNSTBL FOR LT DEC...
W/ DEWPTS IN THE 50S/PWAT 1.50-1.75 INCH/SVRL INSTBY PARAMETERS
STARTING TO REGISTER-- SUCH AS NONZERO MUCAPE...LIS NEAR 0...TQ
15-20...K APPCHG 30. WHILE AM DOUBTING HOW MUCH ACTUAL LTNG THERE WL
BE...SCOPE OF DYNAMICS/WIND FIELD SUGGESTS THAT FNT MAY BE MARKED BY
BKN LINE OF LOW TOPPED CNVCTN ALONG OR JUST AHD OF IT. THIS CUD
BRING DOWN SOME OF THE 40-50 KT KT WINDS PRESENT H9-7. THEREFORE...
HV EXPANDED AREA OF SCHC THUNDER TO JUST ABT ENTIRE CWFA IN THE
EVNG...AND WLL TRIM AS FROPA APPROACHES. PWAT WELL ABV 2SD NOW...
AND INCRSG...SO WL BE ADDING LCL FLOODING TO HWO.
THINK THERE WL BE RAPID DRYING BHD FNT WED NGT AS FLOW VEERS WLY. AM
STILL A LTL HESITANT TO BE TOO SHARP ON BACK SIDE OF POP FIELD IN
CASE LATER GDNC TIMING CHGS AGN...BUT FOR NOW HV MOST OF THE PCPN
ENDING BEFORE 12Z THU.
MIXING POTL WL BE MUCH BETTER THU...STILL W/ A GOOD WIND FIELD.
MEAN LYR MIXING WL YIELD 20-30 KT...W/ SOME GUSTS UP TO 40 KT PSBL
ACRS THE HIER TRRN. THIS WL BE A TIME PD TO MONITOR...AS GRAIDENT
MAY JUSTIFY WND ADVY FOR SOME WRN/NWRN CNTYS W/ AN UPCOMING FCST
CYCLE. WL HOLD THAT IN THE HWO FOR NOW.
EVEN W/ RELATIVELY STRONG CAA...TEMPS IN THE APLCNS WL ONLY
MARGINALLY SUPPORT SHSN...AND THE WLY TRAJ DOESNT HELP MUCH. WL BE
KEEPING CHC POPS FOR WRN UPSLP AREAS THRU THU...BUT WX TYPE SHRASN.
DRY ELSW. MAXT BASED ON MOS MEAN. WL BE ABT 10 DEGF COOLER THAN
WED...WHICH IS STILL ABV CLIMO.
AFTR AN ACTV PD...WX THU NGT THRU FRI NGT WL BE BENIGN AS HIPRES
BLDS. WL EVEN GET TO SEE THE SUN. TEMPS STILL AOA CLIMO.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
A COLD FRONT WILL MOVE ACROSS THE REGION SATURDAY BEFORE SLIDING OFF
TO THE SOUTH AND ACROSS NORTH CAROLINA SATURDAY NIGHT. MUCH OF THE
DAY SATURDAY SHOULD BE DRY. THERE IS A SLIGHT CHANCE OF A FEW RAIN
OR SNOW SHOWERS DEVELOPING POST-FRONTAL LATE SATURDAY AND SATURDAY
NIGHT. MOST OF ANY ENERGY APPEARS TO TAFFY-OUT WELL TO OUR NORTH.
THE SLIGHT CHANCE OF LIGHT STRATIFORM RAIN LINGERS ON SUNDAY AS
ADDITIONAL UPPER LEVEL ENERGY TRIES TO SCOOT SOUTHWARD FROM THE
LOWER GREAT LAKES TO BEHIND THE FRONT WHICH MAY STALL ACROSS THE
CAROLINAS. AS TEMPERATURES DECREASE INTO SUNDAY NIGHT...THERE EXISTS
A SLIGHT CHANCE OF LIGHT SNOW.
MODERATE LEVELS OF UNCERTAINTY LATE SUNDAY THROUGH MONDAY LIES WITH
THE EUROPEAN AND GFS MODELS TRYING TO DEVELOP A LOW ALONG THE
STALLED FRONT OVER THE CAROLINAS AND SPREADING SNOW NORTH INTO OUR
REGION. COLDER AIR FUNNELING IN BEHIND THE COLD FRONT ON A NORTHERLY
WIND AND SEVERAL WAVES OF UPPER ENERGY FROM THE OHIO VALLEY WOULD
PROBABLY SUPPORT THIS. HOWEVER...THE POSITION OF THE POSSIBLE
DEVELOPING LOW ALONG THE FRONT APPEARS TO BE TOO FAR SOUTH TO
PRODUCE A NOTICABLE THREAT OF SNOW. FOR NOW...WENT WITH SLIGHT
CHANCE OF SNOW SUNDAY NIGHT AND A SLIGHT CHANCE TO CHANCE OF LIGHT
RAIN OR LIGHT SNOW MONDAY NIGHT.
AS FOR TUESDAY...WE HAVE A SLIGHT CHANCE OF LIGHT RAIN OR LIGHT SNOW
SHOULD A LOW DEVELOP ALONG THE FRONT. IT ISN`T UNTIL THE MAIN TROUGH
OF LOW PRESSURE PIVOTS ACROSS THE REGION LATE TUESDAY WILL
CONDITIONS IMPROVE.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
LOW CLOUDS AND FOG CONTINUE ACROSS MUCH OF THE REGION. NOT UNTIL
AFTR MIDNIGHT W/ THE ONSET OF STEADY PRECIP WILL WE LOSE THE SUB-IFR
CONDITIONS. CIGS WILL REMAIN LOW THROUGH THE NEXT 24 HRS UNTIL A
COLD FRONT MOVES THRU WED NIGHT. RAIN WILL BE FAIRLY STEADY FROM
LATE TONIGHT AND THRU MUCH OF THE DAYTIME HRS ON WED. ONLY BRIEF
AND INTERMITTENT BREAKS EXPECTED...W/ IFR CIGS OR LOWER.
AOB IFR WL BE PREVALENT WED NGT. LLWS CONCERNS FM THE AFTN WL CARRY
INTO THE EVNG HRS. CFP EITHER LT EVNG OR JUST AFTR MIDNGT. ENUF
UNSEASONABLE WARMTH AND INSTBY FOR LOW TOPPED CNVCTN...MEANING BRIEF
HIER WND GUSTS EMBEDDED W/IN AREAS OF RA. G30-35 KT W/IN REASON.
WORST CASE SCENARIO WUD BE HIER THAN THAT. SLY WNDS WL BECOME WLY
BHD FNT.
MIXING BETTER THU...W/ A WIND FIELD THAT WUD SUPPORT W15G30KT. CIGS
WL LIFT. WL EITHER HV VFR OR MVFR THRU THE DAY.
VFR THU NGT-SAT UNDER HIPRES.
&&
.MARINE...
LIGHT WINDS OVER THE WATERS...THOUGH VSBYS ARE LOW - ESPEC OVER THE
MIDDLE/LOWER MD BAY. WINDS WL RMN LIGHT UNTIL WAVES OF
LIGHT/MODERATE RAIN MOVE IN OVERNIGHT AND INTO EARLY WED. BY
MIDDAY WED...SCA CONDITIONS WILL BECOME APPARENT FROM SOUTH TO
NORTH.
SLY SFC FLOW WL INCR WED NGT...TO ARND 15 KT. MOMENTUM TRANSFER
CHALLENGED...BUT 20-25 KT JUST OFF THE DECK...SO CANT RULE OUT THAT
IT WUD COME DOWN IN SHRA. HIER GUSTS THAT THAT NOT TTLY OUT OF THE
QSTN EITHER...BUT THINK THE ENVIRONMENT WUD MORE LKLY JUSTIFY SMW VS
GLW.
CDFNT WL CROSS WATERS ELY THU MRNG. NW FLOW BHD FRNT WL MIX MORE
EFFECTIVELY. SCA LKLY AND GLW PSBL. SINCE ITS BYD 36 HRS...WL KEEP
IN SYNOPSIS. WL CAP AT SCA LVL FOR THE FCST. WNDS WL SUBSIDE THU NGT
AS HIPRES BLDS.
&&
.TIDES/COASTAL FLOODING...
ANNAP REACHED 2.0 FT AT THE HIGH TIDE WHICH JUST PASSED - BARELY
REACHING ACTION STAGE. ASTRONOMICALLY THIS WAS THE HIGHER OF THE
TWO...SO NO PROBS XPCTD W/ THE MRNG HIGH TIDE. AFTER THAT...XPCT
ANOMALIES TO INCREASE...DRIVEN BY AN UPTICK IN SLY WINDS. THAT MAY
PUT A FEW SITES ALONG THE WESTERN SHORE OF THE BAY ON THE CUSP OF
MINOR FLOODING.
A COLD FRONT WILL PASS EAST OF WATERS BEFORE THE THU MRNG TIDE.
DEPARTURES SHOULD DECREASE A LTL AS A CONSEQUENCE...BUT AM NOT SURE
HOW QUICKLY BLOWOUT CONDS WILL ENSUE.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...DENSE FOG ADVISORY UNTIL 1 AM EST WEDNESDAY FOR MDZ003>006-013-
014-016>018-503>507.
VA...DENSE FOG ADVISORY UNTIL 1 AM EST WEDNESDAY FOR VAZ505.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM WEDNESDAY TO 5 AM EST THURSDAY
FOR ANZ535-536.
SMALL CRAFT ADVISORY FROM 1 PM WEDNESDAY TO 5 AM EST THURSDAY
FOR ANZ530>534-537>543.
&&
$$
UPDATE...WOODY!
PRVS...GMS/HTS/KLW
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
103 PM EST MON DEC 22 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 425 AM EST MON DEC 22 2014
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SW FLOW ALOFT OVER
THE WRN GREAT LKS TO THE E OF A DEEPENING UPR TROF IN THE CENTRAL
CONUS CAUSED BY SHRTWVS DIGGING SEWD IN NW FLOW ALOFT E OF UPR RDG
ALONG THE W COAST. SHRTWV RESPONSIBLE FOR THE SN ON SUN EVNG IS
LIFTING NEWD THRU NW ONTARIO. AS THE ACCOMPANYING STRONGER DYNAMIC
FORCING SHIFTS TO THE NE...IR STLT IMAGERY SHOWS WARMING CLD TOP
TEMPS AS THE COMMA TAIL MSTR BAND SHIFTS TO THE E. ALTHOUGH RADAR
SHOWS THE HEAVIER PCPN IS FOLLOWING OFF TO THE NE...SOME PATCHY
ECHOES REMAIN OVER MUCH OF THE CWA. COMPOSITE RADAR INDICATES
GENERALLY LIGHT MIXED PCPN STRETCHES OFF TO THE SW THRU MUCH OF THE
NW HALF OF WI...WHERE MODELS SHOW AN AXIS OF WEAKER DEEP LYR QVECTOR
CNVGC. SFC OBS INDICATE LOWER SFC DEWPTS OVER NRN LOWER MI...UPWIND
OF THE E HALF OF THE CWA.
MAIN FCST CONCERNS TODAY FOCUS ON DIMINISHING PCPN TRENDS. FOCUS FOR
TNGT SHIFTS TO TIMING THE ARRIVAL OF ANOTHER AREA OF SN/MIXED PCPN
AS ANOTHER SHRTWV LIFTS NEWD OUT OF DEEPENING UPR TROF THAT CAUSES A
CLOSED H5 LO TO DEVELOP IN THE CENTRAL PLAINS.
TODAY...EXPECT SOME GENERALLY LGT SN/MIXED WITH RA TO IMPACT MAINLY
THE W HALF OF THE CWA THRU THIS MRNG AWAY FM THE DRIER NEAR SFC AIR
ADVECTING INTO THE ERN ZNS AND UNDER LINGERING BUT SLOWLY FADING
DEEP LYR QVECTOR CNVGC AS SHRTWV RDG APRCHS FM THE SW. DURING THE
AFTN...ARRIVAL OF DRIER AIR ALOFT FM THE S WITHIN THE NVA SHOULD END
ANY LINGERNING LARGE SCALE PCPN. BUT CONCERNED SOME SN GRAINS/
FREEZING DZ/DZ WL LINGER OVER MAINLY THE CENTRAL CWA WITH UPSLOPE SE
FLOW OFF LK MI. THIS POTENTIAL WL BE LIMITED BY ADVECTION OF LOWER
H95-9 SPECIFIC HUMIDITY NOW OVER NRN LOWER MI...ESPECIALLY OVER THE
E HALF AND BY LATE AFTN EVEN OVER THE CENTRAL. EXPECT TEMPS TO TOP
OUT ABOVE FREEZING EVERYWHERE...SO ANY FREEZING DZ SHOULD END BY
NOON OR SO.
TNGT...AS AREA OF SGNFT DEEP LYR QVECTOR CNVGC/DEEP ISENTROPIC
ASCENT/UPR DVGC IN ADVANCE OF SHRTWV LIFTING NE TOWARD THE GREAT LKS
OVERSPREADS THE AREA...EXPECT PCPN TO DEVELOP OVER THE SCENTRAL BY
MIDNGT AND THEN SPREAD TO OVER ALL THE KEWEENAW BY 12Z TUE. PER NCEP
PREFERENCE...TENDED TOWARD THE 00Z NAM FOR FCST DETAILS. THIS MODEL
GENERATES ABOUT 0.25 INCH OF TOTAL QPF AT MENOMINEE BY 12Z TUE.
PTYPE IS A CONCERN. WHILE THE NAM FCST SDNG FOR MENOMINEE INDICATES
MAINLY RA FOR THAT LOCATION...MODEL SDNGS/H100-85 THKNS INDICATE
AREAS AWAY FM LK MI WL SEE MAINLY SN THRU 12Z TUE. ARRIVAL OF LLVL
DRY AIR TODAY THAT WL ENHANCE NEAR SFC EVAPORATIVE COOLING AND
BACKING NEAR SFC FLOW TOWARD THE ENE THAT WL CUTOFF THE ARRIVAL OF
WARMER AIR APPEAR TO BE THE REASON THE LLVL TEMPS TREND COLD ENUF
FOR MAINLY SN EXCEPT NEAR LK MI. SN/WATER RATIOS WL BE LIMITED BY
RELATIVELY HI/THIN DGZ...SO AN INCH OR TWO OF SN WL LIKELY
ACCUMULATE BY SUNRISE OVER MUCH OF THE SE HALF OF THE CWA TO THE NW
OF THE RA/SN LINE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 438 AM EST MON DEC 22 2014
...WIDESPREAD MODERATE SNOW ON TUESDAY...
ONE PRIMARY CHANCE FOR ACCUMULATING SNOW OVER ALL OF CWA IN THE LONG
TERM ON TUESDAY BUT CANNOT RULE OUT MORE SNOW CHIRSTMAS EVE FOR
EASTERN CWA AS THE ON AGAIN OFF AGAIN LOW PRESSURE SYSTEM IS STILL
AROUND IN LATEST MODELS. ANOTHER SYSTEM MAY IMPACT REGION WITH SWATH
OF SNOW FRIDAY INTO SATURDAY...BUT LACK OF CONTINUITY FM THE MODELS
LIMITS CONFIDENCE IN THAT PART OF FORECAST ATTM.
EVOLVING LOW PRESSURE SYSTEM MOVING OUT OF THE PLAINS TUESDAY INTO
WEDNESDAY APPEARS MORE LIKE RECENT RUNS OF ECMWF. QUESTION IS HOW
FAR EAST THE MID-LEVEL AND SFC LOWS REACH ON TUESDAY AS THAT IMPACTS
DRY SLOT AND PRECIP INTENSITY...ESPECIALLY OVER THE SOUTHERN PART OF
CWA. BLEND OF NAM/SREF SUPPORTED BY NCEP AND LOOKED LIKE 12Z ECMWF.
PRIMARY SHORTWAVE AND SFC LOW MOVE TO EASTERN IOWA BY 12Z TUESDAY
AND LIFT ACROSS EASTERN WISCONSIN ON TUESDAY AFTN. CIRCULATION AROUND
SFC-H85 LOWS PULLS H7 MIXING RATIOS OVER 3G/KG NORTH OF THE LOWS OVER
MAJORITY OF UPR MICHIGAN. PER GARCIA METHOD WITH NO PTYPE
CONSIDERATIONS THAT WOULD FAVOR 3 INCHES OF SNOW IN 6 HRS. BLEND OF
FAVORED QPFS POINT TO 0.30-0.50 INCH OF LIQUID EQUIVALENT OVER MOST
CWA...WITH HIGHER AMOUNTS OVER 0.50 INCH OVER FAR WEST AND SCNTRL.
TROUBLE IS 00Z ECMWF TRENDED EAST WITH SFC LOW AND HAS DRY SLOT INTO
SCNTRL...REALLY CUTTING ITS PRECIP THERE.
PTYPE ALSO AN ISSUE...UNFORTUNATELY. SOUNDINGS FM NAM KEEP BLYR
COOL...WITH ONLY SURE CHANGE TO RAIN AT MNM WITH ENE FLOW OFF BAY OF
GREEN BAY. ENE WINDS WOULD LEAD TO COOLING TO PERSIST AT KESC AND
KISQ. GFS SIMILAR WHILE GEM-REGIONAL IS MUCH WARMER/WESTWARD WITH
1000-850MB THICKNESSES OVER 1305M. SINCE WINDS ARE BACKING AND OFF
LAND IN LOW-LAYERS WILL FAVOR COOLER IDEA OFFERED BY NAM/GFS IN THE
MORNING BUT WILL BRING MORE GEM IDEA IN THE AFTN AS SFC LOW EDGES
CLOSER TO THE AREA FM THE SOUTH. RESULT WILL BE RAIN/SNOW MIX OVER
SCNTRL UPR MICHIGAN ALONG BAY OF GREEN BAY...WITH SNOW ELSEWHERE
INTO EARLY AFTN...THEN GO FOR A MIX OF RAIN AND SNOW OVER MOST OF
THE EAST HALF CWA BY MID AFTN. NAM SOUNDINGS SHOW THE SNOW MAY LAST
THROUGH THE DAY OVER MOST OF THE WEST HALF OF CWA AND EVEN FOLLOWING
GEM THICKNESSES QPF THAT OCCURS THERE IN THE MORNING WOULD STAY ALL
SNOW. OVERALL...WILL LEAN TOWARD MOST SNOW OVER WEST HALF. SOUNDINGS
MAINTAIN LOOK OF ELEVATED NARROW DGZ AND TEMPS WARMER THAN -8C
BLO...SO LOW SLR/S...PROBABLY AROUND 10:1. BY LATE TUESDAY
AFTN...EXPECT TOTAL SNOWFALL OVER 4 INCHES OVER MOST OF THE WEST
HALF OF THE CWA...MAYBE PUSHING TOWARD 6 INCHES OVER INTERIOR WEST.
CLOSER TO LK SUPERIOR OVR NCNTRL WHERE ENE WINDS PROVIDE FLOW OF
LAKE MODIFIED WARMING...EXPECT SNOW TOTALS TO BE HELD DOWN. CONTINUED
TO INCREASE POPS TO CATEGORICAL. IT WILL SNOW. ONLY THING THAT
TEMPERS CONFIDENCE ON ISSUING 3RD PERIOD ADVY IS INCONSISTENCIES IN
WHERE THE HIGHER QPF IS ON MODELS. WILL OPT FOR A SPECIAL WEATHER
STATEMENT AND LET DAYSHIFT GET SOME MORE DATA BEFORE MAKING FINAL
CALL ON HEADLINE.
BULK OF PRECIP WILL BE DONE BY WEDNESDAY EVENING. 00Z NAM WAS QUITE
EMPHATIC WITH DEFORMATION ZONE OF LINGERING SNOW OVER THE WEST CWA
BUT WAS NOT SUPPORTED IN ITS INTENSITY BY ANY OTHER GUIDANCE. 06Z
NAM IS NOT AS BULLISH. THOUGH SOME LGT SNOW COULD CONTINUE AS AN
AREA OF MID LEVEL FGEN/DEFORMATION WILL BE REINFORCED BY WEAK TROWAL.
EVEN THIS AREA OF SNOW SHOULD DIMINISH TO LGT SNOW/FLURRIES LATE ON
TUESDAY NIGHT. FARTHER EAST...SOUNDINGS SIGNAL POSSIBLE DRIZZLE OR
FREEZING DRIZZLE AND FOG AS MID-LEVEL DRYING LEAVES MOIST LOW-LEVELS
WITH TEMPS MAINLY WARMER THAN -7C. CARRIED SLIGHT CHANCE POPS FOR
RAIN/SNOW...BUT THIS MAY NEED TO BE CONVERTED TO DZ/FOG WITH LATER
FORECASTS.
MODELS CONTINUE TO HAVE FUN WITH THE CHRISTMAS EVE SYSTEM AFFECTING
THE GREAT LAKES. AFTER BACKING AWAY COMPLETELY 24 HR AGO...MOST OF
THE MODELS CAME BACK TO SHOWING A STRONG LOW LIFTING NORTHWARD OVER
THE CNTRL GREAT LAKES WITH THE RUNS ON SUNDAY. THAT IS WHERE WE
REMAIN FOR MOST PART NOW...WITH ALL BUT THE GEM-GLOBAL AND PARALLEL
GFS INDICATING THIS SYSTEM MISSES UPR MICHIGAN. KEPT SMALL CHANCES
IN OVER FAR EAST...VCNTY OF LUCE COUNTY...BUT OTHERWISE KEPT THE CWA
VOID OF ANY POPS FM THE SYSTEM. HAVE SOME SMALL CHANCE POPS OVER THE
WEST HALF ON CHRISTMAS EVE DAY...BUT THIS IS GENERALLY DUE TO SOME
SIMBLANCE OF THE LINGERING DEFORMATION AREA FM THE TUESDAY SYSTEM
THAT WILL ONLY BE SLOWLY UNRAVELING OVER THE EAST PART OF CWA ON
WEDNESDAY.
INTO CHRISTMAS AND BEYOND...RAN WITH CONSENSUS. COULD SEE SOME LGT
LK EFFECT FOR WNW-NW FLOW AREAS ON CHRISTMAS THOUGH H85 TEMPS NEAR
-10C ARE ONLY MARGINAL FOR PURE LES. WOULD NEED SOME ADDITIONAL
LARGE SCALE SUPPORT TO RESULT IN BETTER CHANCES OF LES VIA LAKE
ENHANCEMENT. AS LONG AS THE CNTRL GREAT LAKES LOW DOES NOT COME ANY
FARTHER WEST...WILL NOT BE VERY WINDY EITHER. HIGHS ON CHRISTMAS TOP
OUT ABOVE NORMAL...WITH LOW TO MID 30S EXPECTED. AS ALLUDED TO
EARLIER...ANOTHER CLIPPER TYPE SYSTEM COULD SPREAD SOME LGT SNOW TO
THE AREA ON FRIDAY. UNCERTAINTY AND CONSISTENCY IN THAT IDEA BOTH
ARE HIGH...SO CHANCE POPS UNTIL IT GETS MORE REFINED. AT THE MOST
COULD SEE MODERATE SNOW AMOUNTS. IDEA OF COLDER WEATHER WITH LK
EFFECT STILL ON TRACK FOR THE WEEKEND. MOISTURE IS A QUESTION THOUGH
SO EVEN THOUGH H85 TEMPS FALL DOWN BLO -15C ON SUNDAY...EVEN
MODERATE LK EFFECT SNOW IS NOT A DONE DEAL YET. COOLER TEMPS WILL BE
NOTICABLE THOUGH AFTER THE RATHER MILD CHRISTMAS WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1257 PM EST MON DEC 22 2014
MVFR TO IFR CEILINGS COVER MUCH OF UPPER MICHIGAN AS MOIST
SOUTHEASTERLY FLOW IS OCCURRING AHEAD OF A LOW PRESSURE SYSTEM IN
EASTERN SOUTH DAKOTA. AT KSAW...CEILINGS AND VISIBILITES ARE LOWER
DUE TO THE FAVORABLE UPSLOPE WIND DIRECTION. EXPECT THESE LOWER
CLOUDS TO REMAIN INTO THE EVENING HOURS...ALTHOUGH THEY MAY RAISE
SOME TOWARDS LATE AFTERNOON AS DRIER AIR FROM LOWER MICHIGAN
ATTEMPTS TO WORK INTO THE AREA. HAD THE GREATEST CONFIDENCE AT
CONDITIONS STAYING AT OR BELOW MVFR...BUT THERE COULD BE A PERIOD OF
VFR CEILINGS IF THE DRIER AIR CAN WORK INTO THE AREA.
SNOW WILL WORK INTO THE AREA OVERNIGHT INTO TUESDAY AS THE LOW
PRESSURE SYSTEM LIFTS NORTHEAST TOWARDS THE AREA. THERE WILL LIKELY
BE TWO SURGES OF PRECIPITATION WITH THIS LOW...THE FIRST COMING
DURING THE OVERNIGHT HOURS AND THE SECOND ARRIVING BY LATE MORNING
OR EARLY AFTERNOON. THE SECOND WAVE WILL PRODUCE THE STRONGEST SNOW
AND DID DROP KSAW DOWN TO LIFR VISIBILITES TO ACCOUNT FOR THAT
MOVING THROUGH LATE IN THE TAF PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 425 AM EST MON DEC 22 2014
SSE WINDS UP TO 25-30 KTS OVER MAINLY THE E HALF OF LK SUPERIOR WILL
PERSIST THRU TODAY BUT THEN BACK TO THE E TONIGHT AND THEN THE NE ON
TUE AS A LO PRES SYSTEM MOVES NE FROM THE CENTRAL PLAINS TO OVER
LAKE MICHIGAN BY LATE IN THE DAY ON TUE. SINCE THIS LO WILL SLOWLY
WEAKEN AS IT MOVES TO THE NE...THE NE WINDS WILL FALL UNDER 20 KTS
ON TUE NIGHT. SINCE THE LATEST GUIDANCE INDICATES THE NEXT DEEPER LO
WILL TRACK N FARTHER TO THE E ON WED...A WEAKER PRES GRADIENT/N WIND
UNDER 20 KTS WILL DOMINATE ON WED. YET ANOTHER LO PRES MAY MOVE NE
FROM THE CENTRAL PLAINS LATE IN THE WEEK. AT THIS TIME...WINDS UNDER
25 KTS ARE EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...SRF
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
724 AM EST MON DEC 22 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 425 AM EST MON DEC 22 2014
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SW FLOW ALOFT OVER
THE WRN GREAT LKS TO THE E OF A DEEPENING UPR TROF IN THE CENTRAL
CONUS CAUSED BY SHRTWVS DIGGING SEWD IN NW FLOW ALOFT E OF UPR RDG
ALONG THE W COAST. SHRTWV RESPONSIBLE FOR THE SN ON SUN EVNG IS
LIFTING NEWD THRU NW ONTARIO. AS THE ACCOMPANYING STRONGER DYNAMIC
FORCING SHIFTS TO THE NE...IR STLT IMAGERY SHOWS WARMING CLD TOP
TEMPS AS THE COMMA TAIL MSTR BAND SHIFTS TO THE E. ALTHOUGH RADAR
SHOWS THE HEAVIER PCPN IS FOLLOWING OFF TO THE NE...SOME PATCHY
ECHOES REMAIN OVER MUCH OF THE CWA. COMPOSITE RADAR INDICATES
GENERALLY LIGHT MIXED PCPN STRETCHES OFF TO THE SW THRU MUCH OF THE
NW HALF OF WI...WHERE MODELS SHOW AN AXIS OF WEAKER DEEP LYR QVECTOR
CNVGC. SFC OBS INDICATE LOWER SFC DEWPTS OVER NRN LOWER MI...UPWIND
OF THE E HALF OF THE CWA.
MAIN FCST CONCERNS TODAY FOCUS ON DIMINISHING PCPN TRENDS. FOCUS FOR
TNGT SHIFTS TO TIMING THE ARRIVAL OF ANOTHER AREA OF SN/MIXED PCPN
AS ANOTHER SHRTWV LIFTS NEWD OUT OF DEEPENING UPR TROF THAT CAUSES A
CLOSED H5 LO TO DEVELOP IN THE CENTRAL PLAINS.
TODAY...EXPECT SOME GENERALLY LGT SN/MIXED WITH RA TO IMPACT MAINLY
THE W HALF OF THE CWA THRU THIS MRNG AWAY FM THE DRIER NEAR SFC AIR
ADVECTING INTO THE ERN ZNS AND UNDER LINGERING BUT SLOWLY FADING
DEEP LYR QVECTOR CNVGC AS SHRTWV RDG APRCHS FM THE SW. DURING THE
AFTN...ARRIVAL OF DRIER AIR ALOFT FM THE S WITHIN THE NVA SHOULD END
ANY LINGERNING LARGE SCALE PCPN. BUT CONCERNED SOME SN GRAINS/
FREEZING DZ/DZ WL LINGER OVER MAINLY THE CENTRAL CWA WITH UPSLOPE SE
FLOW OFF LK MI. THIS POTENTIAL WL BE LIMITED BY ADVECTION OF LOWER
H95-9 SPECIFIC HUMIDITY NOW OVER NRN LOWER MI...ESPECIALLY OVER THE
E HALF AND BY LATE AFTN EVEN OVER THE CENTRAL. EXPECT TEMPS TO TOP
OUT ABOVE FREEZING EVERYWHERE...SO ANY FREEZING DZ SHOULD END BY
NOON OR SO.
TNGT...AS AREA OF SGNFT DEEP LYR QVECTOR CNVGC/DEEP ISENTROPIC
ASCENT/UPR DVGC IN ADVANCE OF SHRTWV LIFTING NE TOWARD THE GREAT LKS
OVERSPREADS THE AREA...EXPECT PCPN TO DEVELOP OVER THE SCENTRAL BY
MIDNGT AND THEN SPREAD TO OVER ALL THE KEWEENAW BY 12Z TUE. PER NCEP
PREFERENCE...TENDED TOWARD THE 00Z NAM FOR FCST DETAILS. THIS MODEL
GENERATES ABOUT 0.25 INCH OF TOTAL QPF AT MENOMINEE BY 12Z TUE.
PTYPE IS A CONCERN. WHILE THE NAM FCST SDNG FOR MENOMINEE INDICATES
MAINLY RA FOR THAT LOCATION...MODEL SDNGS/H100-85 THKNS INDICATE
AREAS AWAY FM LK MI WL SEE MAINLY SN THRU 12Z TUE. ARRIVAL OF LLVL
DRY AIR TODAY THAT WL ENHANCE NEAR SFC EVAPORATIVE COOLING AND
BACKING NEAR SFC FLOW TOWARD THE ENE THAT WL CUTOFF THE ARRIVAL OF
WARMER AIR APPEAR TO BE THE REASON THE LLVL TEMPS TREND COLD ENUF
FOR MAINLY SN EXCEPT NEAR LK MI. SN/WATER RATIOS WL BE LIMITED BY
RELATIVELY HI/THIN DGZ...SO AN INCH OR TWO OF SN WL LIKELY
ACCUMULATE BY SUNRISE OVER MUCH OF THE SE HALF OF THE CWA TO THE NW
OF THE RA/SN LINE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 438 AM EST MON DEC 22 2014
...WIDESPREAD MODERATE SNOW ON TUESDAY...
ONE PRIMARY CHANCE FOR ACCUMULATING SNOW OVER ALL OF CWA IN THE LONG
TERM ON TUESDAY BUT CANNOT RULE OUT MORE SNOW CHIRSTMAS EVE FOR
EASTERN CWA AS THE ON AGAIN OFF AGAIN LOW PRESSURE SYSTEM IS STILL
AROUND IN LATEST MODELS. ANOTHER SYSTEM MAY IMPACT REGION WITH SWATH
OF SNOW FRIDAY INTO SATURDAY...BUT LACK OF CONTINUITY FM THE MODELS
LIMITS CONFIDENCE IN THAT PART OF FORECAST ATTM.
EVOLVING LOW PRESSURE SYSTEM MOVING OUT OF THE PLAINS TUESDAY INTO
WEDNESDAY APPEARS MORE LIKE RECENT RUNS OF ECMWF. QUESTION IS HOW
FAR EAST THE MID-LEVEL AND SFC LOWS REACH ON TUESDAY AS THAT IMPACTS
DRY SLOT AND PRECIP INTENSITY...ESPECIALLY OVER THE SOUTHERN PART OF
CWA. BLEND OF NAM/SREF SUPPORTED BY NCEP AND LOOKED LIKE 12Z ECMWF.
PRIMARY SHORTWAVE AND SFC LOW MOVE TO EASTERN IOWA BY 12Z TUESDAY
AND LIFT ACROSS EASTERN WISCONSIN ON TUESDAY AFTN. CIRCULATION AROUND
SFC-H85 LOWS PULLS H7 MIXING RATIOS OVER 3G/KG NORTH OF THE LOWS OVER
MAJORITY OF UPR MICHIGAN. PER GARCIA METHOD WITH NO PTYPE
CONSIDERATIONS THAT WOULD FAVOR 3 INCHES OF SNOW IN 6 HRS. BLEND OF
FAVORED QPFS POINT TO 0.30-0.50 INCH OF LIQUID EQUIVALENT OVER MOST
CWA...WITH HIGHER AMOUNTS OVER 0.50 INCH OVER FAR WEST AND SCNTRL.
TROUBLE IS 00Z ECMWF TRENDED EAST WITH SFC LOW AND HAS DRY SLOT INTO
SCNTRL...REALLY CUTTING ITS PRECIP THERE.
PTYPE ALSO AN ISSUE...UNFORTUNATELY. SOUNDINGS FM NAM KEEP BLYR
COOL...WITH ONLY SURE CHANGE TO RAIN AT MNM WITH ENE FLOW OFF BAY OF
GREEN BAY. ENE WINDS WOULD LEAD TO COOLING TO PERSIST AT KESC AND
KISQ. GFS SIMILAR WHILE GEM-REGIONAL IS MUCH WARMER/WESTWARD WITH
1000-850MB THICKNESSES OVER 1305M. SINCE WINDS ARE BACKING AND OFF
LAND IN LOW-LAYERS WILL FAVOR COOLER IDEA OFFERED BY NAM/GFS IN THE
MORNING BUT WILL BRING MORE GEM IDEA IN THE AFTN AS SFC LOW EDGES
CLOSER TO THE AREA FM THE SOUTH. RESULT WILL BE RAIN/SNOW MIX OVER
SCNTRL UPR MICHIGAN ALONG BAY OF GREEN BAY...WITH SNOW ELSEWHERE
INTO EARLY AFTN...THEN GO FOR A MIX OF RAIN AND SNOW OVER MOST OF
THE EAST HALF CWA BY MID AFTN. NAM SOUNDINGS SHOW THE SNOW MAY LAST
THROUGH THE DAY OVER MOST OF THE WEST HALF OF CWA AND EVEN FOLLOWING
GEM THICKNESSES QPF THAT OCCURS THERE IN THE MORNING WOULD STAY ALL
SNOW. OVERALL...WILL LEAN TOWARD MOST SNOW OVER WEST HALF. SOUNDINGS
MAINTAIN LOOK OF ELEVATED NARROW DGZ AND TEMPS WARMER THAN -8C
BLO...SO LOW SLR/S...PROBABLY AROUND 10:1. BY LATE TUESDAY
AFTN...EXPECT TOTAL SNOWFALL OVER 4 INCHES OVER MOST OF THE WEST
HALF OF THE CWA...MAYBE PUSHING TOWARD 6 INCHES OVER INTERIOR WEST.
CLOSER TO LK SUPERIOR OVR NCNTRL WHERE ENE WINDS PROVIDE FLOW OF
LAKE MODIFIED WARMING...EXPECT SNOW TOTALS TO BE HELD DOWN. CONTINUED
TO INCREASE POPS TO CATEGORICAL. IT WILL SNOW. ONLY THING THAT
TEMPERS CONFIDENCE ON ISSUING 3RD PERIOD ADVY IS INCONSISTENCIES IN
WHERE THE HIGHER QPF IS ON MODELS. WILL OPT FOR A SPECIAL WEATHER
STATEMENT AND LET DAYSHIFT GET SOME MORE DATA BEFORE MAKING FINAL
CALL ON HEADLINE.
BULK OF PRECIP WILL BE DONE BY WEDNESDAY EVENING. 00Z NAM WAS QUITE
EMPHATIC WITH DEFORMATION ZONE OF LINGERING SNOW OVER THE WEST CWA
BUT WAS NOT SUPPORTED IN ITS INTENSITY BY ANY OTHER GUIDANCE. 06Z
NAM IS NOT AS BULLISH. THOUGH SOME LGT SNOW COULD CONTINUE AS AN
AREA OF MID LEVEL FGEN/DEFORMATION WILL BE REINFORCED BY WEAK TROWAL.
EVEN THIS AREA OF SNOW SHOULD DIMINISH TO LGT SNOW/FLURRIES LATE ON
TUESDAY NIGHT. FARTHER EAST...SOUNDINGS SIGNAL POSSIBLE DRIZZLE OR
FREEZING DRIZZLE AND FOG AS MID-LEVEL DRYING LEAVES MOIST LOW-LEVELS
WITH TEMPS MAINLY WARMER THAN -7C. CARRIED SLIGHT CHANCE POPS FOR
RAIN/SNOW...BUT THIS MAY NEED TO BE CONVERTED TO DZ/FOG WITH LATER
FORECASTS.
MODELS CONTINUE TO HAVE FUN WITH THE CHRISTMAS EVE SYSTEM AFFECTING
THE GREAT LAKES. AFTER BACKING AWAY COMPLETELY 24 HR AGO...MOST OF
THE MODELS CAME BACK TO SHOWING A STRONG LOW LIFTING NORTHWARD OVER
THE CNTRL GREAT LAKES WITH THE RUNS ON SUNDAY. THAT IS WHERE WE
REMAIN FOR MOST PART NOW...WITH ALL BUT THE GEM-GLOBAL AND PARALLEL
GFS INDICATING THIS SYSTEM MISSES UPR MICHIGAN. KEPT SMALL CHANCES
IN OVER FAR EAST...VCNTY OF LUCE COUNTY...BUT OTHERWISE KEPT THE CWA
VOID OF ANY POPS FM THE SYSTEM. HAVE SOME SMALL CHANCE POPS OVER THE
WEST HALF ON CHRISTMAS EVE DAY...BUT THIS IS GENERALLY DUE TO SOME
SIMBLANCE OF THE LINGERING DEFORMATION AREA FM THE TUESDAY SYSTEM
THAT WILL ONLY BE SLOWLY UNRAVELING OVER THE EAST PART OF CWA ON
WEDNESDAY.
INTO CHRISTMAS AND BEYOND...RAN WITH CONSENSUS. COULD SEE SOME LGT
LK EFFECT FOR WNW-NW FLOW AREAS ON CHRISTMAS THOUGH H85 TEMPS NEAR
-10C ARE ONLY MARGINAL FOR PURE LES. WOULD NEED SOME ADDITIONAL
LARGE SCALE SUPPORT TO RESULT IN BETTER CHANCES OF LES VIA LAKE
ENHANCEMENT. AS LONG AS THE CNTRL GREAT LAKES LOW DOES NOT COME ANY
FARTHER WEST...WILL NOT BE VERY WINDY EITHER. HIGHS ON CHRISTMAS TOP
OUT ABOVE NORMAL...WITH LOW TO MID 30S EXPECTED. AS ALLUDED TO
EARLIER...ANOTHER CLIPPER TYPE SYSTEM COULD SPREAD SOME LGT SNOW TO
THE AREA ON FRIDAY. UNCERTAINTY AND CONSISTENCY IN THAT IDEA BOTH
ARE HIGH...SO CHANCE POPS UNTIL IT GETS MORE REFINED. AT THE MOST
COULD SEE MODERATE SNOW AMOUNTS. IDEA OF COLDER WEATHER WITH LK
EFFECT STILL ON TRACK FOR THE WEEKEND. MOISTURE IS A QUESTION THOUGH
SO EVEN THOUGH H85 TEMPS FALL DOWN BLO -15C ON SUNDAY...EVEN
MODERATE LK EFFECT SNOW IS NOT A DONE DEAL YET. COOLER TEMPS WILL BE
NOTICABLE THOUGH AFTER THE RATHER MILD CHRISTMAS WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 716 AM EST MON DEC 22 2014
AS DEEPER MSTR EXITS TO THE N AND SOME LLVL DRY AIR MOVES IN FM THE
SSE TODAY...EXPECT IMPROVING CONDITIONS THRU THE DAY. BEST CHC FOR
SOME VFR WX WL BE AT IWD...WHERE THE LLVL SE WIND WL DOWNSLOPE. NOT
OUT OF THE QUESTION THAT CMX COULD SEE A PERIOD OF VFR CONDITIONS
LATE THIS AFTN AND EVNG AS WELL. BUT UPSLOPE NATURE OF THE EXPECTED
FLOW INTO SAW SHOULD LIMIT THE IMPROVEMENT THERE TO MVFR. THE APRCH
OF ANOTHER DISTURBANCE/LO PRES FM THE PLAINS WL BRING A RETURN OF
MORE SN LATE TNGT...EARLIEST AT SAW AND THEN OVERSPREADING THE REST
OF UPR MI LATE. SAW SHOULD SEE IFR CONDITIONS LATE WHILE CMX/IWD
FALL TO MVFR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 425 AM EST MON DEC 22 2014
SSE WINDS UP TO 25-30 KTS OVER MAINLY THE E HALF OF LK SUPERIOR WILL
PERSIST THRU TODAY BUT THEN BACK TO THE E TONIGHT AND THEN THE NE ON
TUE AS A LO PRES SYSTEM MOVES NE FROM THE CENTRAL PLAINS TO OVER
LAKE MICHIGAN BY LATE IN THE DAY ON TUE. SINCE THIS LO WILL SLOWLY
WEAKEN AS IT MOVES TO THE NE...THE NE WINDS WILL FALL UNDER 20 KTS
ON TUE NIGHT. SINCE THE LATEST GUIDANCE INDICATES THE NEXT DEEPER LO
WILL TRACK N FARTHER TO THE E ON WED...A WEAKER PRES GRADIENT/N WIND
UNDER 20 KTS WILL DOMINATE ON WED. YET ANOTHER LO PRES MAY MOVE NE
FROM THE CENTRAL PLAINS LATE IN THE WEEK. AT THIS TIME...WINDS UNDER
25 KTS ARE EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
439 AM EST MON DEC 22 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 425 AM EST MON DEC 22 2014
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SW FLOW ALOFT OVER
THE WRN GREAT LKS TO THE E OF A DEEPENING UPR TROF IN THE CENTRAL
CONUS CAUSED BY SHRTWVS DIGGING SEWD IN NW FLOW ALOFT E OF UPR RDG
ALONG THE W COAST. SHRTWV RESPONSIBLE FOR THE SN ON SUN EVNG IS
LIFTING NEWD THRU NW ONTARIO. AS THE ACCOMPANYING STRONGER DYNAMIC
FORCING SHIFTS TO THE NE...IR STLT IMAGERY SHOWS WARMING CLD TOP
TEMPS AS THE COMMA TAIL MSTR BAND SHIFTS TO THE E. ALTHOUGH RADAR
SHOWS THE HEAVIER PCPN IS FOLLOWING OFF TO THE NE...SOME PATCHY
ECHOES REMAIN OVER MUCH OF THE CWA. COMPOSITE RADAR INDICATES
GENERALLY LIGHT MIXED PCPN STRETCHES OFF TO THE SW THRU MUCH OF THE
NW HALF OF WI...WHERE MODELS SHOW AN AXIS OF WEAKER DEEP LYR QVECTOR
CNVGC. SFC OBS INDICATE LOWER SFC DEWPTS OVER NRN LOWER MI...UPWIND
OF THE E HALF OF THE CWA.
MAIN FCST CONCERNS TODAY FOCUS ON DIMINISHING PCPN TRENDS. FOCUS FOR
TNGT SHIFTS TO TIMING THE ARRIVAL OF ANOTHER AREA OF SN/MIXED PCPN
AS ANOTHER SHRTWV LIFTS NEWD OUT OF DEEPENING UPR TROF THAT CAUSES A
CLOSED H5 LO TO DEVELOP IN THE CENTRAL PLAINS.
TODAY...EXPECT SOME GENERALLY LGT SN/MIXED WITH RA TO IMPACT MAINLY
THE W HALF OF THE CWA THRU THIS MRNG AWAY FM THE DRIER NEAR SFC AIR
ADVECTING INTO THE ERN ZNS AND UNDER LINGERING BUT SLOWLY FADING
DEEP LYR QVECTOR CNVGC AS SHRTWV RDG APRCHS FM THE SW. DURING THE
AFTN...ARRIVAL OF DRIER AIR ALOFT FM THE S WITHIN THE NVA SHOULD END
ANY LINGERNING LARGE SCALE PCPN. BUT CONCERNED SOME SN GRAINS/
FREEZING DZ/DZ WL LINGER OVER MAINLY THE CENTRAL CWA WITH UPSLOPE SE
FLOW OFF LK MI. THIS POTENTIAL WL BE LIMITED BY ADVECTION OF LOWER
H95-9 SPECIFIC HUMIDITY NOW OVER NRN LOWER MI...ESPECIALLY OVER THE
E HALF AND BY LATE AFTN EVEN OVER THE CENTRAL. EXPECT TEMPS TO TOP
OUT ABOVE FREEZING EVERYWHERE...SO ANY FREEZING DZ SHOULD END BY
NOON OR SO.
TNGT...AS AREA OF SGNFT DEEP LYR QVECTOR CNVGC/DEEP ISENTROPIC
ASCENT/UPR DVGC IN ADVANCE OF SHRTWV LIFTING NE TOWARD THE GREAT LKS
OVERSPREADS THE AREA...EXPECT PCPN TO DEVELOP OVER THE SCENTRAL BY
MIDNGT AND THEN SPREAD TO OVER ALL THE KEWEENAW BY 12Z TUE. PER NCEP
PREFERENCE...TENDED TOWARD THE 00Z NAM FOR FCST DETAILS. THIS MODEL
GENERATES ABOUT 0.25 INCH OF TOTAL QPF AT MENOMINEE BY 12Z TUE.
PTYPE IS A CONCERN. WHILE THE NAM FCST SDNG FOR MENOMINEE INDICATES
MAINLY RA FOR THAT LOCATION...MODEL SDNGS/H100-85 THKNS INDICATE
AREAS AWAY FM LK MI WL SEE MAINLY SN THRU 12Z TUE. ARRIVAL OF LLVL
DRY AIR TODAY THAT WL ENHANCE NEAR SFC EVAPORATIVE COOLING AND
BACKING NEAR SFC FLOW TOWARD THE ENE THAT WL CUTOFF THE ARRIVAL OF
WARMER AIR APPEAR TO BE THE REASON THE LLVL TEMPS TREND COLD ENUF
FOR MAINLY SN EXCEPT NEAR LK MI. SN/WATER RATIOS WL BE LIMITED BY
RELATIVELY HI/THIN DGZ...SO AN INCH OR TWO OF SN WL LIKELY
ACCUMULATE BY SUNRISE OVER MUCH OF THE SE HALF OF THE CWA TO THE NW
OF THE RA/SN LINE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 438 AM EST MON DEC 22 2014
...WIDESPREAD MODERATE SNOW ON TUESDAY...
ONE PRIMARY CHANCE FOR ACCUMULATING SNOW OVER ALL OF CWA IN THE LONG
TERM ON TUESDAY BUT CANNOT RULE OUT MORE SNOW CHIRSTMAS EVE FOR
EASTERN CWA AS THE ON AGAIN OFF AGAIN LOW PRESSURE SYSTEM IS STILL
AROUND IN LATEST MODELS. ANOTHER SYSTEM MAY IMPACT REGION WITH SWATH
OF SNOW FRIDAY INTO SATURDAY...BUT LACK OF CONTINUITY FM THE MODELS
LIMITS CONFIDENCE IN THAT PART OF FORECAST ATTM.
EVOLVING LOW PRESSURE SYSTEM MOVING OUT OF THE PLAINS TUESDAY INTO
WEDNESDAY APPEARS MORE LIKE RECENT RUNS OF ECMWF. QUESTION IS HOW
FAR EAST THE MID-LEVEL AND SFC LOWS REACH ON TUESDAY AS THAT IMPACTS
DRY SLOT AND PRECIP INTENSITY...ESPECIALLY OVER THE SOUTHERN PART OF
CWA. BLEND OF NAM/SREF SUPPORTED BY NCEP AND LOOKED LIKE 12Z ECMWF.
PRIMARY SHORTWAVE AND SFC LOW MOVE TO EASTERN IOWA BY 12Z TUESDAY
AND LIFT ACROSS EASTERN WISCONSIN ON TUESDAY AFTN. CIRCULATION AROUND
SFC-H85 LOWS PULLS H7 MIXING RATIOS OVER 3G/KG NORTH OF THE LOWS OVER
MAJORITY OF UPR MICHIGAN. PER GARCIA METHOD WITH NO PTYPE
CONSIDERATIONS THAT WOULD FAVOR 3 INCHES OF SNOW IN 6 HRS. BLEND OF
FAVORED QPFS POINT TO 0.30-0.50 INCH OF LIQUID EQUIVALENT OVER MOST
CWA...WITH HIGHER AMOUNTS OVER 0.50 INCH OVER FAR WEST AND SCNTRL.
TROUBLE IS 00Z ECMWF TRENDED EAST WITH SFC LOW AND HAS DRY SLOT INTO
SCNTRL...REALLY CUTTING ITS PRECIP THERE.
PTYPE ALSO AN ISSUE...UNFORTUNATELY. SOUNDINGS FM NAM KEEP BLYR
COOL...WITH ONLY SURE CHANGE TO RAIN AT MNM WITH ENE FLOW OFF BAY OF
GREEN BAY. ENE WINDS WOULD LEAD TO COOLING TO PERSIST AT KESC AND
KISQ. GFS SIMILAR WHILE GEM-REGIONAL IS MUCH WARMER/WESTWARD WITH
1000-850MB THICKNESSES OVER 1305M. SINCE WINDS ARE BACKING AND OFF
LAND IN LOW-LAYERS WILL FAVOR COOLER IDEA OFFERED BY NAM/GFS IN THE
MORNING BUT WILL BRING MORE GEM IDEA IN THE AFTN AS SFC LOW EDGES
CLOSER TO THE AREA FM THE SOUTH. RESULT WILL BE RAIN/SNOW MIX OVER
SCNTRL UPR MICHIGAN ALONG BAY OF GREEN BAY...WITH SNOW ELSEWHERE
INTO EARLY AFTN...THEN GO FOR A MIX OF RAIN AND SNOW OVER MOST OF
THE EAST HALF CWA BY MID AFTN. NAM SOUNDINGS SHOW THE SNOW MAY LAST
THROUGH THE DAY OVER MOST OF THE WEST HALF OF CWA AND EVEN FOLLOWING
GEM THICKNESSES QPF THAT OCCURS THERE IN THE MORNING WOULD STAY ALL
SNOW. OVERALL...WILL LEAN TOWARD MOST SNOW OVER WEST HALF. SOUNDINGS
MAINTAIN LOOK OF ELEVATED NARROW DGZ AND TEMPS WARMER THAN -8C
BLO...SO LOW SLR/S...PROBABLY AROUND 10:1. BY LATE TUESDAY
AFTN...EXPECT TOTAL SNOWFALL OVER 4 INCHES OVER MOST OF THE WEST
HALF OF THE CWA...MAYBE PUSHING TOWARD 6 INCHES OVER INTERIOR WEST.
CLOSER TO LK SUPERIOR OVR NCNTRL WHERE ENE WINDS PROVIDE FLOW OF
LAKE MODIFIED WARMING...EXPECT SNOW TOTALS TO BE HELD DOWN. CONTINUED
TO INCREASE POPS TO CATEGORICAL. IT WILL SNOW. ONLY THING THAT
TEMPERS CONFIDENCE ON ISSUING 3RD PERIOD ADVY IS INCONSISTENCIES IN
WHERE THE HIGHER QPF IS ON MODELS. WILL OPT FOR A SPECIAL WEATHER
STATEMENT AND LET DAYSHIFT GET SOME MORE DATA BEFORE MAKING FINAL
CALL ON HEADLINE.
BULK OF PRECIP WILL BE DONE BY WEDNESDAY EVENING. 00Z NAM WAS QUITE
EMPHATIC WITH DEFORMATION ZONE OF LINGERING SNOW OVER THE WEST CWA
BUT WAS NOT SUPPORTED IN ITS INTENSITY BY ANY OTHER GUIDANCE. 06Z
NAM IS NOT AS BULLISH. THOUGH SOME LGT SNOW COULD CONTINUE AS AN
AREA OF MID LEVEL FGEN/DEFORMATION WILL BE REINFORCED BY WEAK TROWAL.
EVEN THIS AREA OF SNOW SHOULD DIMINISH TO LGT SNOW/FLURRIES LATE ON
TUESDAY NIGHT. FARTHER EAST...SOUNDINGS SIGNAL POSSIBLE DRIZZLE OR
FREEZING DRIZZLE AND FOG AS MID-LEVEL DRYING LEAVES MOIST LOW-LEVELS
WITH TEMPS MAINLY WARMER THAN -7C. CARRIED SLIGHT CHANCE POPS FOR
RAIN/SNOW...BUT THIS MAY NEED TO BE CONVERTED TO DZ/FOG WITH LATER
FORECASTS.
MODELS CONTINUE TO HAVE FUN WITH THE CHRISTMAS EVE SYSTEM AFFECTING
THE GREAT LAKES. AFTER BACKING AWAY COMPLETELY 24 HR AGO...MOST OF
THE MODELS CAME BACK TO SHOWING A STRONG LOW LIFTING NORTHWARD OVER
THE CNTRL GREAT LAKES WITH THE RUNS ON SUNDAY. THAT IS WHERE WE
REMAIN FOR MOST PART NOW...WITH ALL BUT THE GEM-GLOBAL AND PARALLEL
GFS INDICATING THIS SYSTEM MISSES UPR MICHIGAN. KEPT SMALL CHANCES
IN OVER FAR EAST...VCNTY OF LUCE COUNTY...BUT OTHERWISE KEPT THE CWA
VOID OF ANY POPS FM THE SYSTEM. HAVE SOME SMALL CHANCE POPS OVER THE
WEST HALF ON CHRISTMAS EVE DAY...BUT THIS IS GENERALLY DUE TO SOME
SIMBLANCE OF THE LINGERING DEFORMATION AREA FM THE TUESDAY SYSTEM
THAT WILL ONLY BE SLOWLY UNRAVELING OVER THE EAST PART OF CWA ON
WEDNESDAY.
INTO CHRISTMAS AND BEYOND...RAN WITH CONSENSUS. COULD SEE SOME LGT
LK EFFECT FOR WNW-NW FLOW AREAS ON CHRISTMAS THOUGH H85 TEMPS NEAR
-10C ARE ONLY MARGINAL FOR PURE LES. WOULD NEED SOME ADDITIONAL
LARGE SCALE SUPPORT TO RESULT IN BETTER CHANCES OF LES VIA LAKE
ENHANCEMENT. AS LONG AS THE CNTRL GREAT LAKES LOW DOES NOT COME ANY
FARTHER WEST...WILL NOT BE VERY WINDY EITHER. HIGHS ON CHRISTMAS TOP
OUT ABOVE NORMAL...WITH LOW TO MID 30S EXPECTED. AS ALLUDED TO
EARLIER...ANOTHER CLIPPER TYPE SYSTEM COULD SPREAD SOME LGT SNOW TO
THE AREA ON FRIDAY. UNCERTAINTY AND CONSISTENCY IN THAT IDEA BOTH
ARE HIGH...SO CHANCE POPS UNTIL IT GETS MORE REFINED. AT THE MOST
COULD SEE MODERATE SNOW AMOUNTS. IDEA OF COLDER WEATHER WITH LK
EFFECT STILL ON TRACK FOR THE WEEKEND. MOISTURE IS A QUESTION THOUGH
SO EVEN THOUGH H85 TEMPS FALL DOWN BLO -15C ON SUNDAY...EVEN
MODERATE LK EFFECT SNOW IS NOT A DONE DEAL YET. COOLER TEMPS WILL BE
NOTICABLE THOUGH AFTER THE RATHER MILD CHRISTMAS WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1236 AM EST MON DEC 22 2014
LIGHT/MODERATE SNOW CONTINUES ACROSS THE AREA UNDER A SOUTH FLOW OF
MOIST LLVL AIR WITH CONDITIONS RANGING FROM LIFR/VLIFR AT KCMX TO
MVFR AT KIWD. EXPECT IMPROVING CONDITIONS AT KCMX AND KSAW TO HIGH
END IFR LATE TONIGHT AND THEN TO MVFR LATE MON MORNING AS DRIER AIR
MOVES IN FM THE SOUTH. CONDITIONS WILL REMAIN MVFR THROUGH THE PD AT
KIWD AS DOWNSLOPE SOUTH WINDS SHOULD LIMIT LOWER CIGS AND VSBY
RESTRICTIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 425 AM EST MON DEC 22 2014
SSE WINDS UP TO 25-30 KTS OVER MAINLY THE E HALF OF LK SUPERIOR WILL
PERSIST THRU TODAY BUT THEN BACK TO THE E TONIGHT AND THEN THE NE ON
TUE AS A LO PRES SYSTEM MOVES NE FROM THE CENTRAL PLAINS TO OVER
LAKE MICHIGAN BY LATE IN THE DAY ON TUE. SINCE THIS LO WILL SLOWLY
WEAKEN AS IT MOVES TO THE NE...THE NE WINDS WILL FALL UNDER 20 KTS
ON TUE NIGHT. SINCE THE LATEST GUIDANCE INDICATES THE NEXT DEEPER LO
WILL TRACK N FARTHER TO THE E ON WED...A WEAKER PRES GRADIENT/N WIND
UNDER 20 KTS WILL DOMINATE ON WED. YET ANOTHER LO PRES MAY MOVE NE
FROM THE CENTRAL PLAINS LATE IN THE WEEK. AT THIS TIME...WINDS UNDER
25 KTS ARE EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...VOSS
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
430 AM EST MON DEC 22 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 425 AM EST MON DEC 22 2014
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SW FLOW ALOFT OVER
THE WRN GREAT LKS TO THE E OF A DEEPENING UPR TROF IN THE CENTRAL
CONUS CAUSED BY SHRTWVS DIGGING SEWD IN NW FLOW ALOFT E OF UPR RDG
ALONG THE W COAST. SHRTWV RESPONSIBLE FOR THE SN ON SUN EVNG IS
LIFTING NEWD THRU NW ONTARIO. AS THE ACCOMPANYING STRONGER DYNAMIC
FORCING SHIFTS TO THE NE...IR STLT IMAGERY SHOWS WARMING CLD TOP
TEMPS AS THE COMMA TAIL MSTR BAND SHIFTS TO THE E. ALTHOUGH RADAR
SHOWS THE HEAVIER PCPN IS FOLLOWING OFF TO THE NE...SOME PATCHY
ECHOES REMAIN OVER MUCH OF THE CWA. COMPOSITE RADAR INDICATES
GENERALLY LIGHT MIXED PCPN STRETCHES OFF TO THE SW THRU MUCH OF THE
NW HALF OF WI...WHERE MODELS SHOW AN AXIS OF WEAKER DEEP LYR QVECTOR
CNVGC. SFC OBS INDICATE LOWER SFC DEWPTS OVER NRN LOWER MI...UPWIND
OF THE E HALF OF THE CWA.
MAIN FCST CONCERNS TODAY FOCUS ON DIMINISHING PCPN TRENDS. FOCUS FOR
TNGT SHIFTS TO TIMING THE ARRIVAL OF ANOTHER AREA OF SN/MIXED PCPN
AS ANOTHER SHRTWV LIFTS NEWD OUT OF DEEPENING UPR TROF THAT CAUSES A
CLOSED H5 LO TO DEVELOP IN THE CENTRAL PLAINS.
TODAY...EXPECT SOME GENERALLY LGT SN/MIXED WITH RA TO IMPACT MAINLY
THE W HALF OF THE CWA THRU THIS MRNG AWAY FM THE DRIER NEAR SFC AIR
ADVECTING INTO THE ERN ZNS AND UNDER LINGERING BUT SLOWLY FADING
DEEP LYR QVECTOR CNVGC AS SHRTWV RDG APRCHS FM THE SW. DURING THE
AFTN...ARRIVAL OF DRIER AIR ALOFT FM THE S WITHIN THE NVA SHOULD END
ANY LINGERNING LARGE SCALE PCPN. BUT CONCERNED SOME SN GRAINS/
FREEZING DZ/DZ WL LINGER OVER MAINLY THE CENTRAL CWA WITH UPSLOPE SE
FLOW OFF LK MI. THIS POTENTIAL WL BE LIMITED BY ADVECTION OF LOWER
H95-9 SPECIFIC HUMIDITY NOW OVER NRN LOWER MI...ESPECIALLY OVER THE
E HALF AND BY LATE AFTN EVEN OVER THE CENTRAL. EXPECT TEMPS TO TOP
OUT ABOVE FREEZING EVERYWHERE...SO ANY FREEZING DZ SHOULD END BY
NOON OR SO.
TNGT...AS AREA OF SGNFT DEEP LYR QVECTOR CNVGC/DEEP ISENTROPIC
ASCENT/UPR DVGC IN ADVANCE OF SHRTWV LIFTING NE TOWARD THE GREAT LKS
OVERSPREADS THE AREA...EXPECT PCPN TO DEVELOP OVER THE SCENTRAL BY
MIDNGT AND THEN SPREAD TO OVER ALL THE KEWEENAW BY 12Z TUE. PER NCEP
PREFERENCE...TENDED TOWARD THE 00Z NAM FOR FCST DETAILS. THIS MODEL
GENERATES ABOUT 0.25 INCH OF TOTAL QPF AT MENOMINEE BY 12Z TUE.
PTYPE IS A CONCERN. WHILE THE NAM FCST SDNG FOR MENOMINEE INDICATES
MAINLY RA FOR THAT LOCATION...MODEL SDNGS/H100-85 THKNS INDICATE
AREAS AWAY FM LK MI WL SEE MAINLY SN THRU 12Z TUE. ARRIVAL OF LLVL
DRY AIR TODAY THAT WL ENHANCE NEAR SFC EVAPORATIVE COOLING AND
BACKING NEAR SFC FLOW TOWARD THE ENE THAT WL CUTOFF THE ARRIVAL OF
WARMER AIR APPEAR TO BE THE REASON THE LLVL TEMPS TREND COLD ENUF
FOR MAINLY SN EXCEPT NEAR LK MI. SN/WATER RATIOS WL BE LIMITED BY
RELATIVELY HI/THIN DGZ...SO AN INCH OR TWO OF SN WL LIKELY
ACCUMULATE BY SUNRISE OVER MUCH OF THE SE HALF OF THE CWA TO THE NW
OF THE RA/SN LINE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 303 PM EST SUN DEC 21 2014
LONG TERM SHIFT CONTINUES TO BE BUSY THROUGHOUT...BUT IT DOES APPEAR
THAT THE WED-THU STORM IS LESS LIKELY.
A SERIES OF SHORTWAVE TROUGHS WILL MOVE INTO THE CENTRAL CONUS THIS
WEEK...INTENSIFYING AN UPPER TROUGH ALSO OVER THE CENTRAL CONUS
THROUGH MID-WEEK. BY 00Z TUE...MODELS SHOW THAT THE TROUGH HAS
STRENGTHENED TO A CLOSED LOW OVER ERN IA. A LARGE AREA OF PRECIP
WILL EXIST JUST SW OF THE CWA ALONG AND AHEAD OF A SHORTWAVE TROUGH
ROTATING AROUND THE UPPER LOW AND IN AN AREA OF UPPER LEVEL
DIFFLUENCE. LIGHT PRECIP WILL MOVE IN MON NIGHT...WITH THE HEAVIEST
PRECIP EXPECTED TUE MORNING AS YET ANOTHER SHORTWAVE ROTATES AROUND
THE LOW. MODELS VARY IN THE AMOUNT OF QPF...THE 12Z/21 GFS IS ON THE
HIGH SIDE SHOWING WIDESPREAD AMOUNTS AROUND 0.45 INCHES TUE
MORNING...THE 12Z/21 NAM IS 6 HOURS FASTER AND SHOWS SLIGHTLY LESS
QPF...AND THE 00Z/21 ECMWF SHOWS ABOUT HALF THE QPF OF THE GFS. WARM
AIR BEING PULLED FROM THE SE WILL KEEP PRECIP MOSTLY AS RAIN OVER
THE ERN CWA AND MOSTLY SNOW OVER THE WRN CWA. IN BETWEEN...VERTICAL
WET BULB TEMP PROFILES RIGHT AROUND 0C MAKES FOR A MORE DIFFICULT
PTYPE FORECAST...ESPECIALLY WITH UNCERTAINTY. COULD END UP WITH
ADVISORY LEVEL SNOWFALL...BUT UNCERTAINTY REMAINS TOO HIGH TO GET
SPECIFIC WITH SNOWFALL AMOUNTS. FOR THE REST OF TUE AND TUE
NIGHT...THE LOW OVER IA SHOULD WEAKEN AND TRAVERSE ACROSS THE
CWA...WITH ONLY MINOR PRECIP AMOUNTS DURING THIS PERIOD. TUE LOOKS
TO BE THE WARMEST DAY WITH HIGHS IN THE MID TO UPPER 30S.
THE ONLY MODEL CONTINUITY FOR THE FORMER...AND POSSIBLY COULD STILL
BE...CHRISTMAS EVE/DAY STORM IS THAT THERE HAS BEEN NO MODEL
CONTINUITY...AT LEAST OVER THE LAST FEW RUNS. MODELS DID HAVE AT
LEAST SOME DECENT CONTINUITY ABOUT 24 HOURS AGO...BUT AS IS FAIRLY
TYPICAL...ONCE THE FIRST SHORTWAVE MOVED CLOSE/INTO THE BETTER
OBSERVING NETWORK...MODELS DIVERGED FROM THEIR PREVIOUS SOLUTIONS
AND FROM OTHER MODEL SOLUTIONS. HAVE SEEN MODELS RECOVER FROM THE
SWING IN SOLUTIONS FOR SIMILAR STORMS IN THE PAST AND RETURN TO A
SOLUTION MUCH LIKE WAS SHOWED BEFORE THE MODELS SWING. THIS IS THE
CASE WITH THE NEWEST GFS (12Z/21) AS THE PREVIOUS RUN SHOWED THE
SYSTEM MUCH WEAKER AND FARTHER E...BUT THE NEW RUN SHOWS THE UPPER
TROUGH BEING SHARPER AND MORE NEGATIVELY TILTED...RESULTING IN A
CLOSED SFC LOW MOVING N TO LAKE SUPERIOR AT 987MB AT 00Z THU THEN
RAPIDLY MOVING TO ERN QUEBEC NEAR JAMES BAY AT 970MB AT 12Z THU.
WHILE THE GFS IS STILL AN OUTLIER SOLUTION...AND CONFIDENCE IS LOWER
WITH THE GFS DUE TO POOR ENSEMBLE CLUSTERING...THE SOLUTION SHOWN IS
STILL IN THE REALM OF POSSIBILITY. THE 00Z/21 ECMWF IS SIMILAR TO
THE 06Z GFS RUN IN SHOWING THE SYSTEM MUCH WEAKER AND FARTHER E.
EVEN IF THE FARTHEST W GFS VERIFIES...ONLY THE EXTREME ERN CWA WOULD
BE GRAZED BY THE GREATER SYNOPTIC PRECIP. WITH THE MORE BETTER
CONFIDENCE IN THE MORE ERN/WEAKER SOLUTION...PRECIP BEING ALL OR
MOSTLY SNOW BY WED IS FAVORED. STILL WILL SEE SOME SYNOPTIC
SNOW...BUT ONLY MINOR AMOUNTS...AS THE UPPER TROUGH SHIFTS ACROSS
THE AREA. WILL CONTINUE MONITORING CLOSELY...BUT CHANCES FOR A MAJOR
WINTER STORM APPEAR TO BE DWINDLING.
WITH 850MB TEMPS FALLING TO AROUND -8C BY THU AND W-WNW LOW LEVEL
WINDS...COULD SEE SOME LAKE ENHANCED/UPSLOPE SNOW OVER THE
W/KEWEENAW FROM WED NIGHT...WEAKENING THROUGH THE DAY THU AS THE
SYNOPTIC FORCING MOVES E. MODELS THEN BRING ANOTHER SHORTWAVE JUST
SW OF THE CWA ON FRI AHEAD OF AN UPPER TROUGH. OF COURSE...LOTS OF
UNCERTAINTY WITH THE SHORTWAVE...BUT COULD SEE SNOW FRI AS A RESULT.
LAKE EFFECT SNOW AND MUCH COLDER TEMPS ARE THE FOCUS WITH THE UPPER
TROUGH MOVING IN AS 850MB TEMPS FALL TO -20C TO -25C BY SAT MORNING
AND REMAIN OVER THE AREA INTO SUN. IF THIS OCCURS...WILL SEE A GOOD
LES EVEN IN WNW-NW WIND SNOWBELTS LATE FRI INTO AT LEAST SUN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1236 AM EST MON DEC 22 2014
LIGHT/MODERATE SNOW CONTINUES ACROSS THE AREA UNDER A SOUTH FLOW OF
MOIST LLVL AIR WITH CONDITIONS RANGING FROM LIFR/VLIFR AT KCMX TO
MVFR AT KIWD. EXPECT IMPROVING CONDITIONS AT KCMX AND KSAW TO HIGH
END IFR LATE TONIGHT AND THEN TO MVFR LATE MON MORNING AS DRIER AIR
MOVES IN FM THE SOUTH. CONDITIONS WILL REMAIN MVFR THROUGH THE PD AT
KIWD AS DOWNSLOPE SOUTH WINDS SHOULD LIMIT LOWER CIGS AND VSBY
RESTRICTIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 425 AM EST MON DEC 22 2014
SSE WINDS UP TO 25-30 KTS OVER MAINLY THE E HALF OF LK SUPERIOR WILL
PERSIST THRU TODAY BUT THEN BACK TO THE E TONIGHT AND THEN THE NE ON
TUE AS A LO PRES SYSTEM MOVES NE FROM THE CENTRAL PLAINS TO OVER
LAKE MICHIGAN BY LATE IN THE DAY ON TUE. SINCE THIS LO WILL SLOWLY
WEAKEN AS IT MOVES TO THE NE...THE NE WINDS WILL FALL UNDER 20 KTS
ON TUE NIGHT. SINCE THE LATEST GUIDANCE INDICATES THE NEXT DEEPER LO
WILL TRACK N FARTHER TO THE E ON WED...A WEAKER PRES GRADIENT/N WIND
UNDER 20 KTS WILL DOMINATE ON WED. YET ANOTHER LO PRES MAY MOVE NE
FROM THE CENTRAL PLAINS LATE IN THE WEEK. AT THIS TIME...WINDS UNDER
25 KTS ARE EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...VOSS
MARINE...KC
AREA FORECAST DISCUSSION
NWS DULUTH MN
1157 PM CST SUN DEC 21 2014
.UPDATE...
ISSUED AT 1157 PM CST SUN DEC 21 2014
BRIEF UPDATE TO ACCOUNT FOR RADAR TRENDS LATEST GUIDANCE. HAVE DECREASED
SNOWFALL AMOUNTS A BIT TO ACCOUNT FOR THE RAIN/SNOW MIX MOVING UP
FROM THE SOUTH. 00Z NAM/HIRES ARW/HIRES NMM/DLH WRF ALL SUGGEST A
CHANGEOVER TO MOSTLY SNOW NORTH OF HIGHWAY 2 IN NORTHERN MINNESOTA
TOWARDS THE MORNING...WITH THE BEST TIMING FOR SNOW ACROSS THE
ARROWHEAD BETWEEN 10Z AND 16Z. ALONG AND WEST OF HIGHWAY 53
AMOUNTS WILL BE LIGHT AND PRECIP TYPE WILL BE A MIX OF LIGHT
SNOW...FREEZING DRIZZLE/DRIZZLE...AND RAIN DEPENDING ON THE
STRENGTH OF THE MID/LOW LEVEL FORCING AND SURFACE TEMPERATURES.
WINTER WEATHER ADVISORY FOR ARROWHEAD LOOKS TO BE IN GOOD SHAPE AS
CKC /GRAND MARAIS AIRPORT/ HAS BEEN REPORTING LESS THAN 1/4 MI
VISIBILITY WITH A TEMP OF 30. COOK COUNTY DISPATCH DID NOT REPORT
ANY ACCIDENTS/SLIDE OFFS AT LAST REPORT BUT THAT ROADS IN THE
HIGHER TERRAIN WERE SLICK.
UPDATE ISSUED AT 817 PM CST SUN DEC 21 2014
WE ISSUED A WINTER WEATHER ADVISORY FOR TONIGHT INTO MONDAY
MORNING FOR THE IRON RANGE AND ARROWHEAD FOR A COMBINATION OF
FREEZING DRIZZLE AND LIGHT SNOW. AN AREA OF FREEZING DRIZZLE WAS
LIFTING NORTH THROUGH THOSE AREAS AND TEMPERATURES ARE A BIT
COOLER. BUFR SOUNDINGS SHOW MOISTENING AROUND OR SHORTLY AFTER
MIDNIGHT WHICH SHOULD CAUSE THE FREEZING DRIZZLE MIX WITH OR
CHANGE OVER TO SNOW.
UPDATE ISSUED AT 556 PM CST SUN DEC 21 2014
WAA AND A SHORTWAVE HAVE PRODUCED WIDESPREAD SNOW OVER MUCH OF
NORTHWEST WISCONSIN TODAY INTO EARLY THIS EVENING WITH SEVERAL
REPORTS OF 2 TO 3 INCHES SO FAR. RADAR SHOWS THIS SNOW WAS SLOWLY
DIMINISHING FROM WEST TO EAST AND THE VSBY AT KHYR HAS RISEN FROM
A HALF MILE TO 4 MILES. SATELLITE IMAGERY AND FORECAST SOUNDINGS
SHOW DRIZZLE/FREEZING DRIZZLE WILL BE POSSIBLE FURTHER WEST AND WE
HAVE HAD SEVERAL REPORTS OF THAT AS WELL. WE WILL UPDATE GRIDS TO
ACCOUNT FOR THE LATEST TRENDS/PRECIP TYPES.
STRONGER ECHOES WERE ALSO OCCURRING OVER PORTIONS OF SOUTHERN
MINNESOTA. THE HRRR BRINGS THIS AREA NORTH THROUGH THE NIGHT IN
LINE WITH THE OPERATIONAL RUNS. PRECIP TYPE LATER TONIGHT WILL
CONTINUE TO BE A CHALLENGE AND WE WILL MENTION OF MIX OF
SNOW/DRIZZLE OR FREEZING DRIZZLE DEPENDING ON SURFACE TEMPS. BUFR
SOUNDINGS AT KDLH SHOW SNOW BECOMING MORE LIKELY AROUND MIDNIGHT
AS THE COLUMN MOISTENS...WITH KINL LOOKING MORE LIKE
DRIZZLE/FREEZING DRIZZLE THROUGH THE NIGHT AS THE MOISTENING TAKES
LONGER TO REACH THAT AREA. WE WILL ALSO SEE LOW LEVEL TEMPS WARM
LATE TONIGHT INTO MONDAY MORNING WHICH COULD AGAIN CAUSE A MIX TO
OCCUR.
FOG WILL CONTINUE OVERNIGHT WITH LOWEST VSBYS AROUND LAKE
SUPERIOR. WE MAY NEED A DENSE FOG ADVISORY FOR THE NORTH SHORE
DOWN INTO THE TWIN PORTS AREA...BUT WILL WAIT A BIT LONGER BEFORE
ISSUING ONE AS VSBYS HAVE AT LEAST FOR THE TIME BEING COME UP SOME.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY AFTERNOON)
ISSUED AT 329 PM CST SUN DEC 21 2014
MAIN CONCERNS IN THE SHORT TERM REMAIN FOCUSED AROUND THE
INCOMING...LONG DURATION WINTER STORM EXPECTED TO IMPACT THE
NORTHLAND EARLY THIS WEEK WITH A WINTRY MIX OF SNOW...RAIN...SLEET
AND FREEZING DRIZZLE POSSIBLE.
A WINTER STORMS WATCH REMAINS IN EFFECT FOR THE ARROWHEAD INCLUDING
LAKE AND COOK COUNTIES...BUT THE TIME HAS BEEN ADJUSTED TO START
MONDAY NIGHT AND END WEDNESDAY MORNING. THE MAIN CONCERNS WITHIN THE
WATCH AREA WILL BE THE POTENTIAL FOR HEAVY SNOW ACCUMULATIONS.
AN INITIAL LEAD S/W IS ROTATING NEWD THROUGH THE UPPER MIDWEST AND
WRN ONTARIO THIS AFTERNOON AND WILL MOVE SLOWLY EWD TONIGHT AS WEAK
RIDGING ALOFT AND AN ASSOCIATED DRY SLOT PUSH IN FROM THE SOUTH
BEHIND THE WAVE AND AHEAD OF THE MAIN LOW PRESSURE SYSTEM SWINGING
THROUGH THE MIDWEST MON NIGHT THROUGH WEDNESDAY.
WILL SEE SNOW SHOWERS PERSIST THROUGH THIS EVENING WITH LIGHT
ACCUMULATIONS LIKELY. THE HEAVIEST SNOW AMTS TONIGHT WILL BE ACROSS
THE ARROWHEAD AND INTO PORTIONS OF NW WI WHERE AN ADDITIONAL 1 TO 2
INCHES IS POSSIBLE. AS THE UPPER WAVE SLIDES NEWD AND THE RIDGE
BUILDS IN...THE DRY AIR ALOFT WILL ALLOW THE COLUMN TO LOSE ICE
CRYSTALS AND CHANGE THE PRECIP FROM LIGHT SNOW OVER TO A LIGHT
FREEZING DRIZZLE. TEMPERATURES WILL ALSO WARM GRADUALLY THROUGH THE
NIGHT FROM THE LOWER 30S EARLY THIS EVENING TO THE MID 30S BY MON
MORNING. TEMPERATURES ALOFT WILL WARM AS WELL WITH A NOSE OF 0 TO +1
DEG C AIR LIFTS NWD INTO THE AREA AND ALLOWS THE PRECIP TO CHANGE
OVER TO A MIX OF RAIN/SNOW AND/OR SLEET DURING THE DAY MONDAY. WILL
LIKELY SEE WIDESPREAD SNOWFALL AMTS ON MONDAY RANGE FROM A HALF TO
ONE INCH...WITH CLOSER TO 2 TO 3 INCHES POSSIBLE OVER THE ARROWHEAD.
BETTER CHANCES FOR ACCUMULATING SNOW EXIST MON NIGHT THROUGH TUE
NIGHT.
PATCHY FOG WILL ALSO PERSIST TONIGHT AND INTO EARLY IN THE WEEK.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 329 PM CST SUN DEC 21 2014
EXTENDED RANGE FOCUS ON LONG WAVE TROUGH WITH CLOSED H50 THAT TRACKS
THROUGH THE CENTRAL PLAINS AND LIFTS INTO THE GREAT LAKES REGION
DURING THE TUESDAY/WEDNESDAY PERIODS.
ALTHOUGH MODELS ARE COMING INTO BETTER ALIGNMENT...THERE CONTINUES
TO BE RUN TO RUN DIFFERENCES IN TRACK OF THE LOW...WHICH WILL BE THE
DETERMINING FACTOR FOR PLACEMENT OF THE BEST FORCING AND HIGHEST
SNOWFALL AMOUNTS. AT THIS TIME...THE SFC LOW IS FCST TO TRACK OVER
WISCONSIN MONDAY NIGHT/TUESDAY...WHICH WILL PRODUCE GUST NORTHEAST
WINDS OVER LAKE SUPERIOR WHILE ROTATING A BAND OF SNOW LOCATED IN A
DEFORMATION ZONE ON THE ON THE NW FLANK OF THE LOW ACROSS MUCH OF
THE NORTHLAND. LATEST GUIDANCE IS SUGGESTING THAT A CORRIDOR OF QPF
AMOUNTS IN EXCESS OF A HALF INCH WILL BE FOUND DURING THIS TIME DUE
TO THE ABUNDANCE OF MOISTURE AND HIGH PWAT VALUES. ALTHOUGH DETAILS
HAVE YET TO BE REFINED AND SFC TEMPS MAY WARRANT SOME INITIAL MIXING
OF SNOW/RAIN/DRIZZLE...SNOWFALL TOTALS FOR THE MONDAY NIGHT THROUGH
WEDNESDAY MORNING TIME FRAME OF GENERALLY 4 TO 8 INCHES ARE EXPECTED
OVER THE NORTHLAND. THE GREATEST UNCERTAINTY IS IN THE WESTERN HALF
ZONES /NORTH CENTRAL MN/ WHERE A WEDGE OF DRY AIR WILL WRAP AROUND
THE LOW AND LIMIT SNOWFALL TOTALS.
DUE TO THE LONG DURATION OF THE SNOW...ANTICIPATING THAT A WINTER
WEATHER ADVISORY WILL BE NEEDED FOR MUCH OF THE FORECAST AREA DURING
THE MONDAY NIGHT INTO EARLY WEDNESDAY PERIODS.
LONG RANGE MODELS SHOW THE ACTIVE PATTERN THROUGH THE REMAINDER OF
THE EXTENDED FCST...WITH A PERSISTENT CYCLONIC FLOW AND EMBEDDED
SHORT WAVES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1132 PM CST SUN DEC 21 2014
IFR/LIFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD AS PLENTY
OF MOISTURE COVERED THE REGION. AN AREA OF LOW PRESSURE WILL
CONTINUE TO IMPACT THE NORTHLAND THROUGH MONDAY NIGHT WITH PERIODS
OF PRECIPITATION. PRECIPITATION TYPE WILL CONTINUE TO BE A
CHALLENGE. MAINLY DRIZZLE OR FREEZING DRIZZLE WILL OCCUR WHEN THE
PRECIP IS AT ITS LIGHTEST...WITH SLEET OR SNOW OCCURRING WHEN
STRONGER ECHOES MOVE THROUGH. ONE AREA OF STRONGER ECHOES/LIFT WAS
MOVING NORTH UP THE SAINT CROIX RIVER VALLEY INTO NORTHERN
WISCONSIN. BUFR SOUNDINGS CONTINUE TO SHOW ENOUGH SATURATION
OCCURRING AT KHYR/KDLH FOR THE PRECIP TO MIX WITH OR CHANGE OVER
TO SNOW FOR A TIME TONIGHT.
THE LATEST GUIDANCE SUGGESTS THE PRECIP WILL DIMINISH FROM EAST TO
WEST MONDAY AFTERNOON INTO MONDAY EVENING. HOWEVER...WE EXPECT FOG AND
AREAS OF DRIZZLE TO PERSIST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 33 36 33 36 / 100 90 80 80
INL 31 36 32 33 / 90 80 70 70
BRD 32 35 31 34 / 90 90 80 80
HYR 34 36 33 35 / 100 80 80 80
ASX 33 38 33 36 / 100 70 80 80
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 10 AM CST MONDAY FOR MNZ011-012-
019>021.
WINTER STORM WATCH FROM LATE MONDAY NIGHT THROUGH LATE TUESDAY
NIGHT FOR MNZ012-020-021.
WI...NONE.
LS...NONE.
&&
$$
UPDATE...JJM/MELDE
SHORT TERM...BJT
LONG TERM...GRANING
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS DULUTH MN
1132 PM CST SUN DEC 21 2014
.UPDATE...
ISSUED AT 817 PM CST SUN DEC 21 2014
WE ISSUED A WINTER WEATHER ADVISORY FOR TONIGHT INTO MONDAY
MORNING FOR THE IRON RANGE AND ARROWHEAD FOR A COMBINATION OF
FREEZING DRIZZLE AND LIGHT SNOW. AN AREA OF FREEZING DRIZZLE WAS
LIFTING NORTH THROUGH THOSE AREAS AND TEMPERATURES ARE A BIT
COOLER. BUFR SOUNDINGS SHOW MOISTENING AROUND OR SHORTLY AFTER
MIDNIGHT WHICH SHOULD CAUSE THE FREEZING DRIZZLE MIX WITH OR
CHANGE OVER TO SNOW.
UPDATE ISSUED AT 556 PM CST SUN DEC 21 2014
WAA AND A SHORTWAVE HAVE PRODUCED WIDESPREAD SNOW OVER MUCH OF
NORTHWEST WISCONSIN TODAY INTO EARLY THIS EVENING WITH SEVERAL
REPORTS OF 2 TO 3 INCHES SO FAR. RADAR SHOWS THIS SNOW WAS SLOWLY
DIMINISHING FROM WEST TO EAST AND THE VSBY AT KHYR HAS RISEN FROM
A HALF MILE TO 4 MILES. SATELLITE IMAGERY AND FORECAST SOUNDINGS
SHOW DRIZZLE/FREEZING DRIZZLE WILL BE POSSIBLE FURTHER WEST AND WE
HAVE HAD SEVERAL REPORTS OF THAT AS WELL. WE WILL UPDATE GRIDS TO
ACCOUNT FOR THE LATEST TRENDS/PRECIP TYPES.
STRONGER ECHOES WERE ALSO OCCURRING OVER PORTIONS OF SOUTHERN
MINNESOTA. THE HRRR BRINGS THIS AREA NORTH THROUGH THE NIGHT IN
LINE WITH THE OPERATIONAL RUNS. PRECIP TYPE LATER TONIGHT WILL
CONTINUE TO BE A CHALLENGE AND WE WILL MENTION OF MIX OF
SNOW/DRIZZLE OR FREEZING DRIZZLE DEPENDING ON SURFACE TEMPS. BUFR
SOUNDINGS AT KDLH SHOW SNOW BECOMING MORE LIKELY AROUND MIDNIGHT
AS THE COLUMN MOISTENS...WITH KINL LOOKING MORE LIKE
DRIZZLE/FREEZING DRIZZLE THROUGH THE NIGHT AS THE MOISTENING TAKES
LONGER TO REACH THAT AREA. WE WILL ALSO SEE LOW LEVEL TEMPS WARM
LATE TONIGHT INTO MONDAY MORNING WHICH COULD AGAIN CAUSE A MIX TO
OCCUR.
FOG WILL CONTINUE OVERNIGHT WITH LOWEST VSBYS AROUND LAKE
SUPERIOR. WE MAY NEED A DENSE FOG ADVISORY FOR THE NORTH SHORE
DOWN INTO THE TWIN PORTS AREA...BUT WILL WAIT A BIT LONGER BEFORE
ISSUING ONE AS VSBYS HAVE AT LEAST FOR THE TIME BEING COME UP SOME.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY AFTERNOON)
ISSUED AT 329 PM CST SUN DEC 21 2014
MAIN CONCERNS IN THE SHORT TERM REMAIN FOCUSED AROUND THE
INCOMING...LONG DURATION WINTER STORM EXPECTED TO IMPACT THE
NORTHLAND EARLY THIS WEEK WITH A WINTRY MIX OF SNOW...RAIN...SLEET
AND FREEZING DRIZZLE POSSIBLE.
A WINTER STORMS WATCH REMAINS IN EFFECT FOR THE ARROWHEAD INCLUDING
LAKE AND COOK COUNTIES...BUT THE TIME HAS BEEN ADJUSTED TO START
MONDAY NIGHT AND END WEDNESDAY MORNING. THE MAIN CONCERNS WITHIN THE
WATCH AREA WILL BE THE POTENTIAL FOR HEAVY SNOW ACCUMULATIONS.
AN INITIAL LEAD S/W IS ROTATING NEWD THROUGH THE UPPER MIDWEST AND
WRN ONTARIO THIS AFTERNOON AND WILL MOVE SLOWLY EWD TONIGHT AS WEAK
RIDGING ALOFT AND AN ASSOCIATED DRY SLOT PUSH IN FROM THE SOUTH
BEHIND THE WAVE AND AHEAD OF THE MAIN LOW PRESSURE SYSTEM SWINGING
THROUGH THE MIDWEST MON NIGHT THROUGH WEDNESDAY.
WILL SEE SNOW SHOWERS PERSIST THROUGH THIS EVENING WITH LIGHT
ACCUMULATIONS LIKELY. THE HEAVIEST SNOW AMTS TONIGHT WILL BE ACROSS
THE ARROWHEAD AND INTO PORTIONS OF NW WI WHERE AN ADDITIONAL 1 TO 2
INCHES IS POSSIBLE. AS THE UPPER WAVE SLIDES NEWD AND THE RIDGE
BUILDS IN...THE DRY AIR ALOFT WILL ALLOW THE COLUMN TO LOSE ICE
CRYSTALS AND CHANGE THE PRECIP FROM LIGHT SNOW OVER TO A LIGHT
FREEZING DRIZZLE. TEMPERATURES WILL ALSO WARM GRADUALLY THROUGH THE
NIGHT FROM THE LOWER 30S EARLY THIS EVENING TO THE MID 30S BY MON
MORNING. TEMPERATURES ALOFT WILL WARM AS WELL WITH A NOSE OF 0 TO +1
DEG C AIR LIFTS NWD INTO THE AREA AND ALLOWS THE PRECIP TO CHANGE
OVER TO A MIX OF RAIN/SNOW AND/OR SLEET DURING THE DAY MONDAY. WILL
LIKELY SEE WIDESPREAD SNOWFALL AMTS ON MONDAY RANGE FROM A HALF TO
ONE INCH...WITH CLOSER TO 2 TO 3 INCHES POSSIBLE OVER THE ARROWHEAD.
BETTER CHANCES FOR ACCUMULATING SNOW EXIST MON NIGHT THROUGH TUE
NIGHT.
PATCHY FOG WILL ALSO PERSIST TONIGHT AND INTO EARLY IN THE WEEK.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 329 PM CST SUN DEC 21 2014
EXTENDED RANGE FOCUS ON LONG WAVE TROUGH WITH CLOSED H50 THAT TRACKS
THROUGH THE CENTRAL PLAINS AND LIFTS INTO THE GREAT LAKES REGION
DURING THE TUESDAY/WEDNESDAY PERIODS.
ALTHOUGH MODELS ARE COMING INTO BETTER ALIGNMENT...THERE CONTINUES
TO BE RUN TO RUN DIFFERENCES IN TRACK OF THE LOW...WHICH WILL BE THE
DETERMINING FACTOR FOR PLACEMENT OF THE BEST FORCING AND HIGHEST
SNOWFALL AMOUNTS. AT THIS TIME...THE SFC LOW IS FCST TO TRACK OVER
WISCONSIN MONDAY NIGHT/TUESDAY...WHICH WILL PRODUCE GUST NORTHEAST
WINDS OVER LAKE SUPERIOR WHILE ROTATING A BAND OF SNOW LOCATED IN A
DEFORMATION ZONE ON THE ON THE NW FLANK OF THE LOW ACROSS MUCH OF
THE NORTHLAND. LATEST GUIDANCE IS SUGGESTING THAT A CORRIDOR OF QPF
AMOUNTS IN EXCESS OF A HALF INCH WILL BE FOUND DURING THIS TIME DUE
TO THE ABUNDANCE OF MOISTURE AND HIGH PWAT VALUES. ALTHOUGH DETAILS
HAVE YET TO BE REFINED AND SFC TEMPS MAY WARRANT SOME INITIAL MIXING
OF SNOW/RAIN/DRIZZLE...SNOWFALL TOTALS FOR THE MONDAY NIGHT THROUGH
WEDNESDAY MORNING TIME FRAME OF GENERALLY 4 TO 8 INCHES ARE EXPECTED
OVER THE NORTHLAND. THE GREATEST UNCERTAINTY IS IN THE WESTERN HALF
ZONES /NORTH CENTRAL MN/ WHERE A WEDGE OF DRY AIR WILL WRAP AROUND
THE LOW AND LIMIT SNOWFALL TOTALS.
DUE TO THE LONG DURATION OF THE SNOW...ANTICIPATING THAT A WINTER
WEATHER ADVISORY WILL BE NEEDED FOR MUCH OF THE FORECAST AREA DURING
THE MONDAY NIGHT INTO EARLY WEDNESDAY PERIODS.
LONG RANGE MODELS SHOW THE ACTIVE PATTERN THROUGH THE REMAINDER OF
THE EXTENDED FCST...WITH A PERSISTENT CYCLONIC FLOW AND EMBEDDED
SHORT WAVES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1132 PM CST SUN DEC 21 2014
IFR/LIFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD AS PLENTY
OF MOISTURE COVERED THE REGION. AN AREA OF LOW PRESSURE WILL
CONTINUE TO IMPACT THE NORTHLAND THROUGH MONDAY NIGHT WITH PERIODS
OF PRECIPITATION. PRECIPITATION TYPE WILL CONTINUE TO BE A
CHALLENGE. MAINLY DRIZZLE OR FREEZING DRIZZLE WILL OCCUR WHEN THE
PRECIP IS AT ITS LIGHTEST...WITH SLEET OR SNOW OCCURRING WHEN
STRONGER ECHOES MOVE THROUGH. ONE AREA OF STRONGER ECHOES/LIFT WAS
MOVING NORTH UP THE SAINT CROIX RIVER VALLEY INTO NORTHERN
WISCONSIN. BUFR SOUNDINGS CONTINUE TO SHOW ENOUGH SATURATION
OCCURRING AT KHYR/KDLH FOR THE PRECIP TO MIX WITH OR CHANGE OVER
TO SNOW FOR A TIME TONIGHT.
THE LATEST GUIDANCE SUGGESTS THE PRECIP WILL DIMINISH FROM EAST TO
WEST MONDAY AFTERNOON INTO MONDAY EVENING. HOWEVER...WE EXPECT FOG AND
AREAS OF DRIZZLE TO PERSIST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 33 35 33 36 / 70 90 80 80
INL 31 35 32 33 / 50 80 70 70
BRD 32 35 31 34 / 70 90 80 80
HYR 34 35 33 35 / 70 80 80 80
ASX 33 37 33 36 / 70 70 80 80
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 10 AM CST MONDAY FOR MNZ011-012-
019>021.
WINTER STORM WATCH FROM LATE MONDAY NIGHT THROUGH LATE TUESDAY
NIGHT FOR MNZ012-020-021.
WI...NONE.
LS...NONE.
&&
$$
UPDATE...MELDE
SHORT TERM...BJT
LONG TERM...GRANING
AVIATION...MELDE
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
833 PM CST Tue Dec 23 2014
.UPDATE:
Issued at 821 PM CST Tue Dec 23 2014
Digesting the 00Z NAM and HRRR runs and combined they continue to
support the going forecast with a band of rain developing
overnight along and east of the Mississippi River, then mixing/changing
to snow from west to east during the morning hours. Accumulation
will be most likely under the heaviest and most persistent band of
snow which looks to roughly align from KBLV to KTAZ. Only minor
changes were made to the forecast as the placement of the
mesoscale snowband and final adjustments to the forecast will be
a nowcasting exercise by the next shift.
Issued at 650 PM CST Tue Dec 23 2014
Quick update this evening to lower POPs, as it appears that other
than some areas of drizzle across southwest Illinois, the better
shower activity will not develop until after midnight. Still
appears that the majority of the precipitation should fall as rain
tonight, perhaps mixing with snow very late on the western fringe
of the precipitation that develops overnight.
Hope to have another update out by 10 PM after some of the 00Z
model guidance arrives regarding any changes needed to the
snowfall forecast for tomorrow.
CVKING
&&
.SHORT TERM: (Tonight through Wednesday Night)
Issued at 251 PM CST Tue Dec 23 2014
The main forecast issue remains the impending storm system and
potential for accumulating snowfall. The models have come into
much better agreement with mass fields than they exhibited 24
hours ago. Yet, there are still some large issues with thermal
fields, qpf, and speed of the system that are resulting in lower
than normal confidence and higher than normal uncertainty.
The overall scenario is unchanged. The upper low is in the
development process within the southern portion of the deep
positively tilted trof across OK. The guidance is fairly well
clustered lifting the upper low northeast into southwest MO by
daybreak Wednesday to near St. Louis at 18z and into the lower
Great Lakes region by 00z. In response the surface low currently
located along the front in LA will deepen and move through the TN
and OH Vallies over the next 24 hours. Initially the warm conveyor
belt and mid level frontogenetical forcing will be the key players,
with rain presently across AR increasing in coverage and spreading
northeast into southeast Missouri this evening and northeastward
into far east central MO and southwest IL overnight. Model consensus
indicates the thermal profiles should begin cooling sufficiently
on the western fringe of the rain shield after 09z for the rain to
mix and begin changing to snow. After 12z Wednesday the large
scale forcing/ascent really ramps up in association with the
ejecting mid/upper low and this should result in an upswing in
coverage and intensity of precipitation from east central MO into
south central and central IL, and accelerated changeover to snow.
All of the CWA should be entirely snow by 18z, as the deformation
zone precipitation begins shifting away from the CWA. Snow amounts
are still a tough call and there is lots of room for error. The
mean track of the H85 low would place the most-favored axis of
highest precipitation from around Belleville to Decatur, but
during some of the time the rain will be changing to snow. Also
surface temperatures will be in the 32-35F range and SLRs are
expected to be lower than normal with a wet snow expected. The new
forecast has the highest amounts along the aforementioned corridor
with a general 2-3 inches. I wouldn`t be surprised to see locally higher
totals, especially as you head northeastward into central IL.
Given potential the impacts of slushy/slippery roads and reduced
visibility on holiday travel, we have gone ahead an issued a winter
weather advisory even though these amounts are generally below
those we typically consider for an advisory.
Some residual non-accumulating light snow/flurries may linger from
east central MO into IL during the first part of the evening,
however this will be a short window. The system continues its
quick departure with ridging aloft already by 12z Thursday and low
level warm advection underway after 06z.
Glass
.LONG TERM: (Thursday through Next Tuesday)
Issued at 251 PM CST Tue Dec 23 2014
Pronounced warm advection and backing flow aloft in response to
new upstream amplification will dominate Christmas day. The snow
cover will likely be short-lived as temperatures moderate above
normal Thursday into Friday.
A deep and slow progressive long wave trof will then dominate the
upper air pattern into the weekend featuring separate northern and
southern stream components. Present indications are we should see
a cold front passage on Friday night with an attendant threat of
precipitation. An overrunning pattern could then set-up Saturday
into Sunday with snow possible in the deeper cold air, however the
models are quite variable in their depictions of the important features.
Glass
&&
.AVIATION: (For the 00z TAFs through 00z Wednesday Evening)
Issued at 536 PM CST Tue Dec 23 2014
This is a low confidence fcst...esp at the STL metro terminals wrt
precip timing, type and assoc VSBYs. A an ill defined cold front is
mvng thru the area this evng setting the stage for a tricky fcst for
tomorrow. CIGs lower progressively behind the front eventually bcmng
IFR by mrng. An upper level disturbance will eject out of the sthrn
plains overnight and move NE thru tomorrow to near the Grt Lks by Wed
evng. A sfc low across the deep south will deepen and track into the
TN vly tonight and on into the OH vly tomorrow. An area of precip is
expected to dvlp to our south overnight and move towards the STL metro
area terminals by early Wed mrng. Current indications are that the STL
metro area will be on the wrn fringes of the precip tomorrow mrng. This
poses a couple of issues...first, whether the precip actually impacts
the metro area. KCPS has a better chance than KSUS. Secondly, if the
terminals are not in the heart of the precip, then they will not be
collocated under the best upper level forcing needed to switch the precip
over to snow. Given this scenario, there is a chance that precip may
mix with snow at times but not switch over completely. If this occurs,
then the VSBYs for tomorrow mrng are too low. The possibility exists
for KCPS to see the precip switch over to all snow with some accums
and KSUS to not see much precip at all. It is a tough call attm and
will require updates to capture the short term trends. Any precip should
exit to the NE by 18Z with just some lingering lght precip for the aftn.
KUIN is not expected to be impacted by this system other than an outside
chance at some very lght precip late tomorrow mrng. Cntrl MO may have
a batch of lght precip move in from wrn MO during the aftn in response
to another upper lvl disturbance. This also looks like a mix with no
significant impacts expected. The IFR CIGs should hang tough thru the
end of the prd. Kept the basic flavor of the previous fcst and will
wait for addntl guidance before making significant adjustments.
Specifics for KSTL:
Low confidence fcst into Wed aftn. An upper level disturbance will pass
over the region tomorrow and drive a sfc low into the OH vly by tomorrow
evng. Many questions surround this upcoming system. There is significant
model spread on where the wrn edge of the precip shield will set up
tomorrow. Best guess now is somewhere in the STL metro area. This poses
an addntl problem, if the terminal is not in the heart of the precip
then it will not be collocated under the best forcing needed to switch
the precip over to snow. If that is the case, then the precip may not
mix with or change over to snow at all meaning VSBYs for tomorrow mrng
are too low. If the precip materializes, it should move to the NE by
18Z leaving only lght precip in its wake for the remainder of the aftn.
The IFR VSBYs are expected to remain in place thru the end of the fcst
prd.
2%
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY from 6 AM to 6 PM CST Wednesday FOR
Jefferson MO-St. Charles MO-St. Louis City MO-St. Louis MO.
IL...WINTER WEATHER ADVISORY from 6 AM to 6 PM CST Wednesday FOR Bond
IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-Macoupin IL-
Madison IL-Marion IL-Monroe IL-Montgomery IL-St. Clair IL-
Washington IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
358 PM MST MON DEC 22 2014
.SHORT TERM...VALID FOR TUE AND WED...
UNSETTLED NORTHWEST FLOW OVER THE REGION WITH A BETTER AREA OF
WRAP AROUND SNOWFALL IN SOUTHEAST MONTANA WHERE ACCUMULATIONS OF
1/2 INCH TO AN INCH HAVE BEEN REPORTED WITH OBSERVATIONS SHOWING
20 TO 30 MPH WINDS. RADARS SHOW SNOW STILL MOVING INTO THE AREA
WITH RAP FORECASTING ADDITIONAL SNOWFALL THROUGH THE EVENING
HOURS. WILL KEEP THE ADVISORY FOR FALLON AND CARTER COUNTIES BUT
ECHOS ARE DECREASING FOR CUSTER AND POWDER RIVER COUNTIES SO WILL
CANCEL THE ADVISORIES FOR THOSE AREAS.
TUESDAY IS A QUIETER WEATHER DAY ACROSS THE REGION AS HEIGHTS
BUILD AND THE AIRMASS DRIES OUT. A SERIES OF DISTURBANCES MOVING
THROUGH BC BEGIN A ROUND OF LEESIDE TROUGHING LATE IN THE DAY WITH
WILL PROMOTE SOME MIXING BUT TEMPERATURES WILL NOT REBOUND PAST
THE 30S. LEESIDE TROUGHING STRENGTHENS TUESDAY NIGHT WHICH SETS UP
GAP FLOW WINDS FOR LIVINGSTON AND NYE AREAS. GUIDANCE SHOWS WIND
ADVISORY CRITERIA WINDS DEVELOPING AFTER MIDNIGHT SO WILL NOT
ISSUE A HIGHLIGHT YET BUT WILL BEGIN MESSAGING ABOUT A PERIOD OF
STRONG WINDS ALONG I90 LATE TUESDAY INTO WEDNESDAY.
ENERGY CONTINUES TO STREAM ACROSS ALBERTA AND BC WEDNESDAY WITH A
STRONGER WAVE MOVING INTO WASHINGTON AND OREGON DURING THE DAY.
THIS MAINTAINS THE FAVORABLE PRESSURE GRADIENTS AND INCREASES
MIXING SO TEMPERATURES WILL BE WARMER BY A FEW DEGREES. APPROACH
OF THE DISTURBANCE WEDNESDAY NIGHT ALLOWS A COLD FRONT TO MOVE
NORTH TO SOUTH THROUGH MONTANA WITH THE HEIGHTS FALLING. THE
ALIGNMENT OF THE FRONT MOVING INTO SOUTHERN MONTANA AFTER MIDNIGHT
AND THE DYNAMICS OF THE UPSTREAM WAVE INCREASING THE MOISTURE IN
THE AIRMASS WILL ALLOW FOR THE DEVELOPMENT OF SNOW AND
FRONTOGENESIS. EXPECT SNOW TO BEGIN FOR AREAS AROUND JUDITH GAP
AND HARLOWTON WEDNESDAY EVENING AND SPREADING SOUTH OVERNIGHT. BY
LATE WEDNESDAY NIGHT EXPECT MOST AREAS TO SEE SOME SNOW FALLING
WITH THE EXCEPTION OF SHERIDAN COUNTY WHICH MAY STILL BE WAITING A
FEW HOURS FOR IT TO DEVELOP.
THE FAVORABLE INGREDIENTS LATE WEDNESDAY NIGHT SHOULD YIELD 1 TO 3
INCHES OF SNOWFALL BY DAYBREAK WITH SNOW CONTINUING WITH THE
HIGHER AMOUNTS EXPECTED WEST OF BILLINGS...SOUTHEAST MONTANA
ACCUMULATIONS WILL BE CLOSER TO AN INCH. WINDS BECOMING UPSLOPE
WILL HELP SNOWFALL RATES INCREASE IN THE LATE NIGHT HOURS WITH A
GOOD RATE OF SNOWFALL EXPECTED AT THE VERY END OF THE SHORT TERM
FORECAST PERIOD. BILLINGS HAS NOT HAD AN INCH OR BETTER OF
SNOWFALL ON CHRISTMAS DAY SINCE 1988 AND SHERIDAN SINCE 1996 SO
THIS WILL BE A NOTABLE EVENT. THE RECORD SNOWFALL FOR BILLINGS FOR
CHRISTMAS DAY OF 4.5 INCHES COULD BE THREATENED. BORSUM
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
THE MAIN FOCUS IN THE EXTENDED REMAINS THE SNOW ON CHRISTMAS DAY.
THE LATEST RUNS OF THE GFS AND ECMWF HAVE COME INTO BETTER
AGREEMENT WITH EACH OTHER. THE 12Z NAM IS MAYBE SLIGHTLY FASTER
THAN THE GFS/ECMWF...BUT THE GEM IS THE MAIN OUTLIER...MAINTAINING THE
FASTER SOLUTION. HAVE TRENDED THE SNOW AMOUNTS UP
SLIGHTLY...GENERALLY 3 TO 5 ACROSS MUCH OF THE PLAINS...WITH
AMOUNTS INCREASING TO WEST INTO THE MOUNTAINS. WINDS WILL BE OUT
OF THE NORTH FOR MUCH OF CHRISTMAS DAY...WHICH SETS UP A GOD
UPSLOPE FLOW EVENT FOR THE MOUNTAINS. BUFKIT SOUNDINGS ARE SHOWING
A VERY MOIST DENDRIDIC GROWTH LAYER THROUGH MUCH OF THE DAY...SO
EXPECTING GOOD SNOWFALL RATES OUT OF THIS SYSTEM.
GIVEN THAT THE AREA WILL BE UNDER CLOUD COVER WITH FALLING
SNOW...HAVE KEPT TEMPERATURES CHRISTMAS DAY A LITTLE COOLER THAN
GUIDANCE. THROUGHOUT THE EXTENDED...TEMPERATURES WILL REMAIN
COLD...WITH HIGHS GENERALLY IN THE 20S TO LOWER 30S...AND LOWS
DROPPING INTO THE TEENS.
FRIDAY THINGS SHOULD DRY OUT AS THE SYSTEM MOVES INTO THE CENTRAL
PLAINS. SATURDAY SHOULD BE ANOTHER QUIET DAY ACROSS THE
AREA...BEFORE WE SEE THE NEXT TROUGH MOVE INTO THE AREA WITH
ANOTHER ROUND OF SNOW SUNDAY. THE GFS IS A BIT FASTER WITH THIS
SECOND SYSTEM...BUT AT THIS POINT AM GOING WITH A BLEND OF THE
MODELS GIVEN THAT THIS IS AT THE END OF THE FORECAST PERIOD.
REIMER
&&
.AVIATION...
LIGHT SNOW SHOWERS WILL CONTINUE ACROSS THE AREA THROUGH
MIDNIGHT...WITH THE HEAVIER SNOWFALL FROM MILES CITY TO BROADUS
AND EAST. GENERALLY VFR CONDITIONS WILL PREVAIL. SOME SNOW SHOWERS
WILL PRODUCE SOME BRIEF LOCALIZED MVFR CONDITIONS...AND CONTINUE
TO OBSCURE THE MOUNTAINS. WINDS WILL REMAIN GUSTY THROUGH MID
EVENING. REIMER
&&
.PRELIMINARY POINT TEMP/POPS...
TUE WED THU FRI SAT SUN MON
-----------------------------------------------------------
BIL 025/039 026/042 027/028 012/025 012/029 018/027 008/019
20/N 01/B 78/J 51/B 11/B 23/J 32/J
LVM 014/034 023/042 025/026 012/028 011/031 018/030 009/023
20/N 02/W +9/J 62/J 11/N 23/J 32/J
HDN 022/037 019/042 026/027 010/025 010/028 015/027 008/019
30/B 11/B 58/J 52/J 11/B 23/J 32/J
MLS 021/035 019/042 026/027 013/023 009/028 013/024 006/016
41/B 11/E 66/J 41/E 11/B 22/J 22/J
4BQ 024/034 017/042 025/026 014/024 007/027 013/027 007/019
52/S 11/B 47/J 42/J 11/B 13/J 32/J
BHK 024/029 015/038 024/025 008/019 007/025 009/021 003/013
72/S 11/B 45/J 41/E 11/B 22/J 22/J
SHR 025/036 018/042 025/026 012/026 008/031 013/029 010/022
41/B 01/B 48/J 52/J 11/B 13/J 32/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 AM MST TUESDAY FOR
ZONES 33-37.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
515 PM CST TUE DEC 23 2014
.SHORT TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 300 PM CST TUE DEC 23 2014
BAND OF GENERALLY LIGHT MIXED PRECIP CONTINUES TO TRACK SLOWLY
SOUTH ACROSS SOUTHEAST NEBRASKA AND SOUTHWEST IOWA AT 20Z. THIS
TREND IS EXPECTED TO CONTINUE INTO THE EVENING AS UPPER TROUGH
MOVES SLOWLY EAST. TEMPERATURES ARE IN THE MID TO UPPER 30S SO
WHATEVER SNOW DOES FALL MELTS FAIRLY QUICKLY. NDOR WEB CAMS SHOW
LITTLE TO NO SNOW COVER SOUTH OF A COLUMBUS TO TEKAMAH LINE.
LATEST RAP MODEL INDICATES A DIMINISHING TREND TO THE PRECIP THIS
EVENING WITH ONLY MINOR ACCUMULATIONS EXPECTED AS TEMPERATURES
FALL TO NEAR 32 THROUGH 06Z. STRONGER DYNAMICS SHIFT WELL EAST OF
THE AREA TONIGHT TO THE TENNESSEE AND LOWER OHIO VALLEY WITH
SHORT WAVE RIDGING BUILDING INTO THE NORTHERN PLAINS.
FORECAST SOUNDINGS SUGGEST DECREASING CLOUDS ACROSS THE AREA FOR
WEDNESDAY ALTHOUGH EASTERN AREAS MAY BE LIMITED TO LATE AFTERNOON
FOR ANY POTENTIAL VIEWING OF SUNSHINE. CLEARING TREND CONTINUES
WEDNESDAY NIGHT INTO THURSDAY BEFORE CLOUDS INCREASE ONCE AGAIN
THURSDAY NIGHT AND FRIDAY BEHIND THE NEXT COLD FRONT AND
APPROACHING UPPER TROUGH. SOME LIGHT SNOW IS LIKELY AGAIN WITH
THIS SYSTEM ON FRIDAY BUT NO MAJOR IMPACT ON TRAVEL IS EXPECTED.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 300 PM CST TUE DEC 23 2014
SNOW MAY LINGER INTO FRIDAY NIGHT FOR SOUTHERN PARTS OF THE AREA
THEN DRY BUT COLD FOR THE WEEKEND. STRONG TROUGHING DEVELOPS OVER
THE CENTRAL PART OF THE NATION EARLY NEXT WEEK WITH MUCH COLDER
AIR ON TAP FOR THE END OF THE YEAR.
&&
.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 515 PM CST TUE DEC 23 2014
MAIN AREA OF PCPN WILL SHIFT SOUTH OUT OF THE KOMA AND KLNK AREAS
THIS EVENING. IFR CEILINGS AND MVFR VSBYS SHOULD CONTINUE AT THESE
TWO SITES WITH WINDS INCREASING A BIT. CEILINGS ARE EXPECT TO RISE
INTO THE MVFR CATEGORY BY MID OR LATE MORNING WED. VFR CONDITIONS
MAY DEVELOP AT KLNK IN THE AFTN. FOR KOFK...IFR CEILINGS ARE
LIKELY UNTIL AROUND 12Z WED...WITH CONDITIONS BECOMING VFR BY 18Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...FOBERT
LONG TERM...FOBERT
AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1152 PM CST SUN DEC 21 2014
.UPDATE...
ISSUED AT 524 PM CST SUN DEC 21 2014
A LIGHT MIST HAS FORMED ACROSS PORTIONS OF THE FORECAST AREA AND
BASED ON RADAR TRENDS IS EXPANDING IN COVERAGE AREA. IN
ADDITION...FORECAST SOUNDINGS INDICATE THAT THE SATURATED STRATUS
LAYER IS NOW THICKER THAN 1 KM...WHICH IS A SUFFICIENT DEPTH FOR
DRIZZLE FORMATION. THEREFORE...HAVE INTRODUCED DRIZZLE TO THE
FORECAST FOR THE EVENING AND EARLY MORNING HOURS.
SATELLITE IMAGERY INDICATES OVERCAST CONDITIONS ACROSS OUR ENTIRE
FORECAST AREA AND LATEST NAM AND RUC RH FIELDS SHOW LITTLE HOPE
FOR ANY BREAKS IN THE CLOUDS THROUGH THE OVERNIGHT HOURS ACROSS
MOST OF OUR FORECAST AREA. THEREFORE...HAVE INCREASED CLOUD COVER
FOR TONIGHT TO 100 PERCENT CLOUD COVER FOR MOST AREAS EXCEPT FOR
FAR SOUTHWESTERN ZONES WHERE THERE COULD BE A FEW BREAKS IN THE
CLOUDS. BUT EVEN ACROSS SOUTHWESTERN ZONES IT SHOULD STILL BE
MOSTLY CLOUDY TONIGHT.
THE COMBINATION OF CLOUDS...DRIZZLE...AND EVEN LIGHT RAIN LATER
TONIGHT WILL KEEP SURFACE TEMPERATURES NEARLY STEADY THROUGH THE
OVERNIGHT HOURS...WHICH IS SUPPORTED BY MOST FORECAST MODELS.
THEREFORE...INCREASED LOWS FOR TONIGHT BY A FEW DEGREES KEEPING
ALL AREAS ABOVE FREEZING TONIGHT FOR LOWS. THE NEAR SURFACE LAYER
(SFC-875MB) SHOULD BE SUFFICIENTLY WARM BASED ON MODEL FORECAST
SOUNDINGS TO KEEP ALL PRECIPITATION IN THE LIQUID FORM THROUGH THE
OVERNIGHT HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 349 PM CST SUN DEC 21 2014
SATELLITE AND OBSERVATIONS CONTINUE TO SHOW A VERY PERSISTENT AREA
OF LOW CLOUDS AND FOG OVER PORTIONS OF THE FORECAST AREA. MID LEVEL
CLOUDS FROM THE WEST ARE MOVING INTO THE AREA AND MAKING IT HARDER
TO SEE THE STRATUS...BUT RECENT SATELLITE TRENDS HAS BEEN FOR THE
NORTH/NORTHWEST PROGRESSION OF THE STRATUS HAS SLOWED OR EVEN
STOPPED. DURING THE DAYTIME THE FOG HAS REDUCED VISIBILITY MORE THAN
EARLY THIS MORNING. EVEN WITH GOOD SOUTH WINDS THE FOG HAS SPREAD
ACROSS THE FORECAST AREA. THE SOUTH WINDS HAVE BROUGHT A CONTINUE
STREAM OF MORE MOIST AIR INTO THE REGION WHICH COULD ACCOUNT FOR
SOME OF THE INCREASE IN CLOUDS AND FOG.
A WEAK UPPER LEVEL WAVE MOVED THROUGH THE FORECAST AREA TODAY. THIS
IS HELPING TO BRING IN THE MID LEVEL CLOUDS. AT THE SURFACE THERE IS
A DEVELOPING LOW AND COLD FRONT ON THE HIGH PLAINS. THIS COLD FRONT
IS EXPECTED TO MOVE THROUGH THE FORECAST AREA TONIGHT AS A STRONGER
UPPER LEVEL WAVE APPROACHES THE AREA. PRECIPITATION IS EXPECTED TO
DEVELOP TO THE WEST LATE THIS AFTERNOON AND SPREAD INTO THE AREA
THIS EVENING AND TONIGHT. THE BEST CHANCES FOR PRECIPITATION WILL BE
IN THE NORTH AND IN THE EAST. THE PRECIPITATION SHOULD BE MAINLY OUT
OF THE FORECAST AREA BY MORNING. LOOKING AT FORECAST SOUNDINGS THE
PRECIPITATION SHOULD BE RAIN DURING THE NIGHT TONIGHT. TEMPERATURES
SHOULD REMAIN WARM ENOUGH THAT IT WILL BE LIQUID. THE NORTHWEST HAVE
LOW TEMPERATURES THAT ARE AROUND FREEZING BY MORNING...BUT
PRECIPITATION SHOULD BE OUT OF THERE BEFORE IT ACTUALLY DROPS BELOW
FREEZING.
ON MONDAY THE PRECIPITATION SHOULD BE WRAP AROUND FROM THE UPPER LOW
IN THE DAKOTAS. BY THEN THE TEMPERATURES ALOFT START TO COOL OFF AND
SO THERE WILL BE SOME RAIN AND SNOW MIXED DURING THE MORNING IN THE
NORTH. BY AFTERNOON IT SPREADS A LITTLE FURTHER SOUTH. BY THIS TIME
THE SURFACE TEMPERATURES WARM A LITTLE AS THE TEMPERATURES ALOFT
COOL AND ONCE AGAIN EXPECT A MIX OF RAIN AND SNOW. BY LATE IN THE
AFTERNOON TEMPERATURES COULD BE FALLING IN THE FAR NORTH.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 349 PM CST SUN DEC 21 2014
WE START OFF THE LONG TERM MONDAY NIGHT ON THE BACK SIDE OF A MID-
UPPER CLOSED LOW...ASSOCIATED WITH A DEEPENING LONGWAVE TROUGH AS IT
MOVES TOWARD THE MISSISSIPPI VALLEY. FROM MONDAY NIGHT INTO
TUESDAY/TUESDAY EVENING...WE WILL BE IN A REGION OF LIGHT WRAP
AROUND PRECIPITATION...KEEPING RATHER GLOOMY CONDITIONS AROUND
LONGER. THE TRICKY PART IS FIGURING OUT WHAT GOES ON TUESDAY. MOST
NUMERICAL MODELS ARE PLACING AT LEAST SOME QPF OVER THE CWA...AND
THE NAM/SREF ARE HITTING OUR KANSAS COUNTIES HARDER. THE NAM IS
DISPLAYING .20 INCHES OF QPF AND HAS BEEN CONSISTENT WITH THIS IN
THE PAST COUPLE OF RUNS. THE PROBLEM IS THAT I DO NOT SEE ENOUGH
EVIDENCE TO SUPPORT THE HIGHER CHANCES OF PRECIPITATION ADVERTISED
BY THE SREF ENSEMBLES AND THE NAM QPF. ALL NUMERICAL MODELS SEEM TO
BREAK OFF A SMALL PIECE OF ENERGY THAT WRAPS AROUND THE CLOSED LOW
THAT SHOULD BE LOCATED JUST NORTHEAST OF THE CWA. THIS IS QUITE A
SMALL FEATURE AND IT IS DIFFICULT TO JUDGE WHERE AND IF THIS ENDS UP
ANYWHERE OVER OUR CWA. THERE IS A FAIR AMOUNT OF DOWNGLIDE AND THERE
DOES NOT APPEAR TO BE MUCH SYNOPTIC SCALE LIFT FOR SUPPORT. THERE IS
SOME MID-LEVEL FRONTOGENETIC FORCING FROM THE NAM. THIS WILL BE AN
AREA TO KEEP AN EYE ON. OUR STORM TOTAL SNOW GRID IS GENERALLY IN
THE 1 TO 2 INCH RANGE FOR MONDAY NIGHT/TUESDAY. I HAVE OPTED TO GO A
BIT HIGHER WITH POPS FROM MY NEIGHBORS AND GO WITH 40 POPS...AS I
STILL AM UNCOMFORTABLE WITH WIDE AGREEMENT AMONG MOST NUMERICAL
MODELS THAT WE WILL MEASURE.
WE WILL GET A REPRIEVE FROM PRECIPITATION CHANCES WEDNESDAY...WITH
UPPER LEVEL RIDGING OCCURRING...BUT THIS WILL BE SHORT-LIVED AS
SYNOPTIC FLOW IS PROGRESSIVE. THE TROUGH HITTING THE PACIFIC
NORTHWEST WEDNESDAY EVENING COULD GIVE US A SHOT AT PRECIPITATION AS
EARLY AS THURSDAY AFTERNOON...ESPECIALLY NORTHWEST AS THE TROUGH BY
00Z FRIDAY WILL IS FORECAST TO BE POSITIVELY TILTED FROM THE
NORTHERN GREAT PLAINS TO THE CENTRAL/SOUTHERN ROCKY MOUNTAINS. THIS
QUICK-MOVING WAVE CAN GIVE US A SHOT AT SOME SNOW...BUT AMOUNTS DO
NOT LOOK OVERWHELMING AS THE TROUGH AXIS MAKES ITS WAY EAST OF THE
CWA BY LATE THURSDAY NIGHT...NOT HANGING AROUND LONG ENOUGH FOR
LARGER AMOUNTS. WIND WILL KICK UP BEHIND THE ASSOCIATED COLD FRONT
THURSDAY NIGHT...PROBABLY REDUCING VISIBILITY CHRISTMAS NIGHT FROM
THE BLOWING SNOW. THE WIND WILL CONTINUE TO BE BRISK ON
FRIDAY...CREATING AN UNCOMFORTABLE DAY AFTER CHRISTMAS...WITH COOLER
HIGHS BEHIND THE COLD FRONT NEAR 30 TO THE MID 30S. STILL LOOKS
TROUGHY HEADING INTO THE WEEKEND...SO THE DRY FORECAST IS NOT THE
MOST CONFIDENT. TEMPERATURES WILL BE SEASONABLY COOL.
NUMERICAL MODELS ARE SYNOPTICALLY SIMILAR FOR THE LONG TERM...SO
CONFIDENCE IS FAIRLY HIGH FOR TEMPERATURES AND FOR THE MOST
PART...PRECIPITATION...ALTHOUGH THERE ARE SMALLER SCALE DIFFERENCES
THAT NEED TO BE HAMMERED OUT AS WE APPROACH THEM.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1138 PM CST SUN DEC 21 2014
AN UPPER LEVEL DISTURBANCE CROSSING THE REGION WILL BE THE DRIVING
FORCE FOR THE WEATHER OVER THIS TAF PERIOD. NOT A WHOLE LOT OF
PRECIP IN THE AREA AT THE MOMENT...BUT THERE IS ANOTHER SMALL
BATCH WHICH WILL MOVE IN FROM THE NW WITH TIME. DECIDED TO KEEP
PRECIP MENTION AT A TEMPO GROUP...AS THE RAP/HRRR MODELS SUGGEST
THAT IT MAY NOT HOLD TOGETHER. WILL SEE HOW THINGS TREND OVER THE
NEXT FEW HOURS. OTHERWISE...EXPECTING IFR CEILINGS TO STICK
AROUND...VISBYS ARE VFR BUT WOULDNT BE SURPRISED TO SEE THEM AT
LEAST BRIEFLY DROP TO MVFR. MAY SEE SOME IMPROVEMENT DURING THE
DAYTIME HOURS WITH A COLD FRONT MOVING THROUGH THE REGION...AND
NWRLY WINDS BEHIND THE FRONT WILL INCREASE TO NEAR 20 MPH WITH
HIGHER GUSTS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...WESELY
SHORT TERM...JCB
LONG TERM...HEINLEIN
AVIATION...ADP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
940 PM EST TUE DEC 23 2014
.SYNOPSIS...
A STORM SYSTEM OVER THE EASTERN GREAT LAKES WILL BRING RAIN TO
OUR REGION INTO WEDNESDAY NIGHT. A COLD FRONT EARLY CHRISTMAS
MORNING WILL BRING RAIN SHOWERS AND EVEN A FEW THUNDERSTORMS WITH
GUSTY WINDS. IT WILL BE WINDY AND CHILLY FOR THE REMAINDER OF
CHRISTMAS DAY WITH A CHANCE OF RAIN AND SNOW SHOWERS. A RIDGE OF
HIGH PRESSURE WILL BRING FAIR WEATHER TO OUR REGION ON FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
940 PM UPDATE...
CHANGED POP GRIDS OVERNIGHT TO REFLECT THE RAIN ADVANCING INTO THE
FA FROM THE WEST BETWEEN 7Z AND 11Z. STUCK TO CATEGORICAL POPS FOR
THE EARLY MORNING HOURS ONCE THE RAIN GETS ESTABLISHED NEAR SUNRISE.
ALSO REWORKED THE TEMPERATURE GRIDS AS IT APPEARS WE HAVE ALREADY
SEEN OUR MINS FOR THE NIGHT. TEMPERATURES ARE HOLDING STEADY OR
RISING ATTM. USING A BLEND OF THE HRRR AND LAMP, WE CAME UP WITH A
REALISTIC LOOKING HOURLY TEMPERATURE PROG FOR THE OVERNIGHT. THE
RAP INITIALIZED WAY TOO COLD AT THE SURFACE OVER THE EAST, SO WE
THREW IT OUT THIS RUN.
130 PM UPDATE...
RADARS SHOW AN AREA OF RAIN ACROSS NC AND ERN NY AND THE LATEST
HRRR HAS DONE A DECENT JOB OF SIMULATING THIS. THIS PRECIPITATION
WAS ASSCTD WITH A SHORT WAVE THAT WAS MAKING ITS WAY INTO NEW
ENGLAND. THE HRRR ADVECTS THIS RAIN EASTWARD BY 20-21Z W/ NE PA
AND C NY CONTINUING UNDER A VERY MOIST SERLY LOW-LEVEL FLO. THIS
MOIST FLO WILL CONT PATCHY AREAS OF LIGHT RAIN AND DRIZZLE INTO
THE EVENING AND OVERNIGHT HOURS AS OUR AREA WILL BE IN A LULL IN
THE HEAVIER RAINS. A MUCH MORE SIGNIFICANT AND LARGER PRECIPITATION
SHIELD WILL ARRIVE BTWN ABT 9 AND 12Z WED FROM S TO N ACRS NE PA/C
NY. THE DYNAMICS AND MOISTURE TRANSPORT WERE FAIRLY IMPRESSIVE
FOR WED/WED EVE.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS A LARGE UPPER LEVEL
WAVE PRESENTLY OVER TEXAS MOVING INTO THE BASE OF A LONG WAVE
TROF. THE DYNAMIC TROPOPAUSE WAS DOWN TO ABT 530 MB WITH THIS
FEATURE. THIS WAVE WILL RIDE NE UP THRU THE MIDWEST WEDNESDAY AND
CLOSE OFF TO A 500 MB LOW BY 00Z THU OVER LWR MI. AS THIS OCCURS
OUR AREA COMES UNDER DEEP UPPER LEVEL DVRG AND AN ACCELERATING
S-SWRLY LOW-LEVEL FLOW WHICH PEAKS AT ABT 50 KNOTS AT 850 MB WED
AFTERNOON AND EVENING. ALL THE SYNOPTIC SCALE MODELS INDICATE A
MAX IN QPF EAST OF A LINE FROM ABT AVP TO ALB. THE FINGER LAKES
REGION TO WRN NY IS IN A LOCAL MINIMUM ON ALL SYNOPTIC MODELS
INCLUDING 12Z EURO...12Z GFS...12Z NAM AND 12Z CMC. THIS MAKES
SENSE AS THE LL FLOW IS S-SWRLY AND THE LLJ WHICH FOCUSES MOISTURE
AND PRECIPITATION WILL BE SPLIT BY THE APPLCNS. THE EURO...GFS AND
CMC ALL AGREE THAT THE MAXIMUM QPF IS BTWN 1 AND 1.5 INCHES MAINLY
ACRS AREAS E OF A LINE FROM AVP TO DELAWARE CO NY IN OUR FORECAST
AREA WITH .25 TO .5 INCHES QPF IN THE FINGER LAKES. THE NAM IS
HEAVY HANDED WITH THE QPF AND HAS OVER 2 INCHES IN OUR FAR ERN
ZONES AND .5 INCHES IN THE FINGER LAKES. ONLY LOCALLY CUD I SEE 2
INCHES IN THE CATSKILLS AND POCONOS...BUT NOT WIDESPREAD ENUF TO
CAUSE SIGNIFICANT HYDRO ISSUES. SNOWPACK WAS MINIMAL IN THESE
AREAS SO WE ARE EXPECTING RISES TO AT LEAST 1/2 TO 3/4 BANKFUL
ON MANY RIVERS AND TRIBUARTIES BUT NO FLOOD ISSUES OF SIGNIFICANCE
OTHER THAN URBAN FLOODING. SO NO FLOOD WATCH AT THIS TIME. PRECIP
WILL CONTINUE INTO WED EVE OFF AND ON. TEMPERATURES WILL HOLD
STEADY AND SLOWLY RISE THRU WEDNESDAY.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
FOR WEDNESDAY NIGHT...MAIN CONCERN IS THE POTENTIAL FOR A QLCS OR
NARROW COLD FRONTAL RAIN BAND ALONG THE COLD FRONT WHICH SWINGS
THRU THE REGION BY 4-8Z THU. TIMING OF THIS FRONT IS STILL UNCERTAIN
BUT IT APPEARS IT WILL COME THRU JUST AFTER MIDNIGHT OR SO. THE
DYNAMICS ARE VERY IMPRESSIVE AS ALL SYNOPTIC MODELS SHOW A STRG
UPPER LEVEL PV MAX SWINGING THRU WITH SRG DVRG ALOFT ERLY THU AM.
THE LOW TO MID LEVEL WINDS AT FROPA WERE VERY STRG WITH 0-1 KM
BULK SHEAR AT 45 KNOTS, 0-3 KM ARND 50-60 KNOTS AND 0-6 KM FROM 80
TO 100 KNOTS DEPENDING ON THE MODEL. 0-1 KM HELICITIES WERE
PROGGED CLOSE TO 300 M2/S2. CAPES WERE MARGINAL WHICH IS TO BE
EXPECTED... RUNNING POTENTIALLY UP TO 250 J/KG OR SO MAINLY IN OUR
ERN ZONES. DEWPOINTS ARE PROJECTED TO CLIMB ABV 50F IN THE SRLY
FLOW...ESPECIALLY ACRS NE PA TO EC NY. MODELS SHOW THAT THE DWPTS
AT 850 MB CLIMB ABV 10C WHICH IS 50F AS WELL ACRS ENTIRE AREA. WE
RAN OUR LOCAL SVR WX ANALOG CHECKLIST WHICH COMPARES FORECAST
PARAMETERS WITH HISTORICAL EVENTS AND IT RETURNED 4 OUT OF 5
EVENTS THAT HAD SIGNIFICANT WIND DAMAGE. 3 OF THE 5 EVENTS HAD
ISOLATED TORNADOES INCLUDING THE F2 OF DEC 2006 WHICH HIT NE PA.
FOR NOW HAVE MENTION OF THUNDERSTORMS WITH GUSTY WINDS IN GRIDS
WED NGT/ERLY THU. WILL HIGHLIGHT POTENTIAL FOR STRONG TO LOCALLY
SEVERE THUNDERSTORMS IN THE HWO AS SPC HAS SOME OF OUR AREA IN A
MARGINAL RISK.
AFTER FROPA ON CHRISTMAS DAY...IT WILL BE WINDY WITH PRESSURE
RISES OF ABT 10 TO 15 MB / 12 HOURS IN C NY WHICH IS CLOSE TO
ADVY CRITERIA. WILL MENTION POTENTIAL FOR WIND GUSTS TO 50 MPH IN
HWO FOR C NY...MAINLY FINGER LAKES REGION TO SYR/RME AREAS. THERE
WILL ALSO BE SCT RAIN AND SNOW SHOWERS ARND IN THE BACKLASH OF
THIS LARGE CYCLONE WHICH TAPERS OFF THU NGT.
FRIDAY WILL BE FAIR AND STILL MILD AS A RDG OF HIGH PRESSUIE
BUILDS ACRS THE REGION AS HGHTS RAPIDLY RISE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE OVERALL 500 MB PATTERN DOES NOT CHANGE MUCH THROUGH THIS
PERIOD WITH A BROAD TROF RESIDENT OVER CENTRAL NORTH AMERICA WITH
RELATIVELY MILD SWLY FLOW ACROSS THE CNY/NEPA REGION. THIS WILL
KEEP US IN A RATHER ACTIVE PATTERN WITH TRANSIENT WEATHER SYSTEMS
MOVING THROUGH THE REGION.
MEDIUM RANGE MODEL CONSENSUS IS RATHER POOR...BUT IT DOES APPEAR
THE BEST CHANCE FOR PRECIPITATION WILL BE SAT NIGHT-SUN ASSOCIATED
WITH A COLD FRONT...AND THEN A MORE MARGINAL EVENT SLATED FOR
MONDAY AS LOW PRESSURE LIFTS THROUGH THE TN/OH VALLEY PER THE
ECMWF. THIS IS UNLESS THE GFS/GGEM CONTINUE TO TREND A FLATTER
WAVE OUT TO SEA TO OUR SOUTH MISSING US COMPLETELY. WPC GRIDS SEEM
TO BE HEAVY HANDED ON THE ECMWF SOLUTIONS...BUT GIVEN UNCERTAINTY
INTRODUCED BY GFS/GGEM...WE HAVE SOFTENED THEM TO CHANCE POPS IN
THIS AREA FROM SUN-MON NGT. BEYOND THEN...WEAK WAVES AND PASSING
FLURRIES POSSIBLE THROUGH MID-WEEK.
OVERALL...TEMPERATURES WITHIN THE BROAD SWLY FLOW WILL BE NEAR TO
ABOVE LATE DECEMBER NORMALS.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
MILD MOIST CONDITIONS WILL REMAIN ACROSS THE AREA TONIGHT WITH
MVFR AND IFR CIGS AND MOSTLY MVFR TO VFR VSBYS THROUGH THE
EVENING. CONDITIONS WILL PROBABLY LOWER A BIT OVERNIGHT WITH MANY
AREAS LIKELY EXPERIENCING IFR CONDITIONS OVERNIGHT INTO WEDNESDAY
MORNING. PRECIPITATION WILL BE IN THE FORM OF SPOTTY LIGHT DRIZZLE
LATE TONIGHT... THEN STEADIER RAIN WILL OVERSPREAD THE AREA FROM
THE SOUTH FROM 10-15Z WEDNESDAY MORNING. CONDITIONS WILL BE MAINLY
MVFR IN RAIN THROUGH THE DAY WEDNESDAY. SOME LOW LEVEL WIND SHEAR
WILL DEVELOP WEDNESDAY AFTERNOON WITH SOUTHERLY FLOW INCREASING TO
40-45 KTS AT 2000 FEET WHILE WINDS NEAR THE SURFACE REMAIN LIGHT
FROM THE SOUTHEAST.
OUTLOOK...
WED NGT...IFR. PERIODS OF RAIN.
THU...BECOMING VFR...AREAS MVFR. WINDY WITH SHOWERS.
FRI/SAT...VFR. CHC SHRA SAT.
SUN...MVFR/IFR. CHC RAIN OR SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN/DJP
NEAR TERM...DJN/DJP
SHORT TERM...DJN
LONG TERM...JAB
AVIATION...JAB/MSE
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
650 PM EST TUE DEC 23 2014
.SYNOPSIS...
A LARGE STORM SYSTEM WILL TRACK NORTHEAST FROM THE SOUTH CENTRAL
PLAINS TO THE EASTERN GREAT LAKES TONIGHT AND WEDNESDAY AND THEN
INTO CANADA BY CHRISTMAS DAY. THIS STORM WILL BRING A WIDESPREAD
RAIN TO OUR REGION BEGINNING LATER TONIGHT AND LASTING INTO
WEDNESDAY NIGHT. THE STORM WILL ALSO SWING A COLD FRONT THROUGH
THE REGION EARLY CHRISTMAS MORNING WITH RAIN SHOWERS AND EVEN A
FEW THUNDERSTORMS WITH GUSTY WINDS. AFTER THE FRONT PASSES BY CHRISTMAS
MORNING...IT WILL BE WINDY AND CHILLY FOR THE REMAINDER OF
CHRISTMAS DAY WITH A CHANCE OF RAIN AND SNOW SHOWERS. A RIDGE OF
HIGH PRESSURE WILL BRING FAIR AND MILD WEATHER TO OUR REGION ON
FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
130 PM UPDATE...
RADARS SHOW AN AREA OF RAIN ACROSS NC AND ERN NY AND THE LATEST
HRRR HAS DONE A DECENT JOB OF SIMULATING THIS. THIS PRECIPITATION
WAS ASSCTD WITH A SHORT WAVE THAT WAS MAKING ITS WAY INTO NEW
ENGLAND. THE HRRR ADVECTS THIS RAIN EASTWARD BY 20-21Z W/ NE PA
AND C NY CONTINUING UNDER A VERY MOIST SERLY LOW-LEVEL FLO. THIS
MOIST FLO WILL CONT PATCHY AREAS OF LIGHT RAIN AND DRIZZLE INTO
THE EVENING AND OVERNIGHT HOURS AS OUR AREA WILL BE IN A LULL IN
THE HEAVIER RAINS. A MUCH MORE SIGNIFICANT AND LARGER PRECIPITATION
SHIELD WILL ARRIVE BTWN ABT 9 AND 12Z WED FROM S TO N ACRS NE PA/C
NY. THE DYNAMICS AND MOISTURE TRANSPORT WERE FAIRLY IMPRESSIVE
FOR WED/WED EVE.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS A LARGE UPPER LEVEL
WAVE PRESENTLY OVER TEXAS MOVING INTO THE BASE OF A LONG WAVE
TROF. THE DYNAMIC TROPOPAUSE WAS DOWN TO ABT 530 MB WITH THIS
FEATURE. THIS WAVE WILL RIDE NE UP THRU THE MIDWEST WEDNESDAY AND
CLOSE OFF TO A 500 MB LOW BY 00Z THU OVER LWR MI. AS THIS OCCURS
OUR AREA COMES UNDER DEEP UPPER LEVEL DVRG AND AN ACCELERATING
S-SWRLY LOW-LEVEL FLOW WHICH PEAKS AT ABT 50 KNOTS AT 850 MB WED
AFTERNOON AND EVENING. ALL THE SYNOPTIC SCALE MODELS INDICATE A
MAX IN QPF EAST OF A LINE FROM ABT AVP TO ALB. THE FINGER LAKES
REGION TO WRN NY IS IN A LOCAL MINIMUM ON ALL SYNOPTIC MODELS
INCLUDING 12Z EURO...12Z GFS...12Z NAM AND 12Z CMC. THIS MAKES
SENSE AS THE LL FLOW IS S-SWRLY AND THE LLJ WHICH FOCUSES MOISTURE
AND PRECIPITATION WILL BE SPLIT BY THE APPLCNS. THE EURO...GFS AND
CMC ALL AGREE THAT THE MAXIMUM QPF IS BTWN 1 AND 1.5 INCHES MAINLY
ACRS AREAS E OF A LINE FROM AVP TO DELAWARE CO NY IN OUR FORECAST
AREA WITH .25 TO .5 INCHES QPF IN THE FINGER LAKES. THE NAM IS
HEAVY HANDED WITH THE QPF AND HAS OVER 2 INCHES IN OUR FAR ERN
ZONES AND .5 INCHES IN THE FINGER LAKES. ONLY LOCALLY CUD I SEE 2
INCHES IN THE CATSKILLS AND POCONOS...BUT NOT WIDESPREAD ENUF TO
CAUSE SIGNIFICANT HYDRO ISSUES. SNOWPACK WAS MINIMAL IN THESE
AREAS SO WE ARE EXPECTING RISES TO AT LEAST 1/2 TO 3/4 BANKFUL
ON MANY RIVERS AND TRIBUARTIES BUT NO FLOOD ISSUES OF SIGNIFICANCE
OTHER THAN URBAN FLOODING. SO NO FLOOD WATCH AT THIS TIME. PRECIP
WILL CONTINUE INTO WED EVE OFF AND ON. TEMPERATURES WILL HOLD
STEADY AND SLOWLY RISE THRU WEDNESDAY.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
FOR WEDNESDAY NIGHT...MAIN CONCERN IS THE POTENTIAL FOR A QLCS OR
NARROW COLD FRONTAL RAIN BAND ALONG THE COLD FRONT WHICH SWINGS
THRU THE REGION BY 4-8Z THU. TIMING OF THIS FRONT IS STILL UNCERTAIN
BUT IT APPEARS IT WILL COME THRU JUST AFTER MIDNIGHT OR SO. THE
DYNAMICS ARE VERY IMPRESSIVE AS ALL SYNOPTIC MODELS SHOW A STRG
UPPER LEVEL PV MAX SWINGING THRU WITH SRG DVRG ALOFT ERLY THU AM.
THE LOW TO MID LEVEL WINDS AT FROPA WERE VERY STRG WITH 0-1 KM
BULK SHEAR AT 45 KNOTS, 0-3 KM ARND 50-60 KNOTS AND 0-6 KM FROM 80
TO 100 KNOTS DEPENDING ON THE MODEL. 0-1 KM HELICITIES WERE
PROGGED CLOSE TO 300 M2/S2. CAPES WERE MARGINAL WHICH IS TO BE
EXPECTED... RUNNING POTENTIALLY UP TO 250 J/KG OR SO MAINLY IN OUR
ERN ZONES. DEWPOINTS ARE PROJECTED TO CLIMB ABV 50F IN THE SRLY
FLOW...ESPECIALLY ACRS NE PA TO EC NY. MODELS SHOW THAT THE DWPTS
AT 850 MB CLIMB ABV 10C WHICH IS 50F AS WELL ACRS ENTIRE AREA. WE
RAN OUR LOCAL SVR WX ANALOG CHECKLIST WHICH COMPARES FORECAST
PARAMETERS WITH HISTORICAL EVENTS AND IT RETURNED 4 OUT OF 5
EVENTS THAT HAD SIGNIFICANT WIND DAMAGE. 3 OF THE 5 EVENTS HAD
ISOLATED TORNADOES INCLUDING THE F2 OF DEC 2006 WHICH HIT NE PA.
FOR NOW HAVE MENTION OF THUNDERSTORMS WITH GUSTY WINDS IN GRIDS
WED NGT/ERLY THU. WILL HIGHLIGHT POTENTIAL FOR STRONG TO LOCALLY
SEVERE THUNDERSTORMS IN THE HWO AS SPC HAS SOME OF OUR AREA IN A
MARGINAL RISK.
AFTER FROPA ON CHRISTMAS DAY...IT WILL BE WINDY WITH PRESSURE
RISES OF ABT 10 TO 15 MB / 12 HOURS IN C NY WHICH IS CLOSE TO
ADVY CRITERIA. WILL MENTION POTENTIAL FOR WIND GUSTS TO 50 MPH IN
HWO FOR C NY...MAINLY FINGER LAKES REGION TO SYR/RME AREAS. THERE
WILL ALSO BE SCT RAIN AND SNOW SHOWERS ARND IN THE BACKLASH OF
THIS LARGE CYCLONE WHICH TAPERS OFF THU NGT.
FRIDAY WILL BE FAIR AND STILL MILD AS A RDG OF HIGH PRESSUIE
BUILDS ACRS THE REGION AS HGHTS RAPIDLY RISE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE OVERALL 500 MB PATTERN DOES NOT CHANGE MUCH THROUGH THIS
PERIOD WITH A BROAD TROF RESIDENT OVER CENTRAL NORTH AMERICA WITH
RELATIVELY MILD SWLY FLOW ACROSS THE CNY/NEPA REGION. THIS WILL
KEEP US IN A RATHER ACTIVE PATTERN WITH TRANSIENT WEATHER SYSTEMS
MOVING THROUGH THE REGION.
MEDIUM RANGE MODEL CONSENSUS IS RATHER POOR...BUT IT DOES APPEAR
THE BEST CHANCE FOR PRECIPITATION WILL BE SAT NIGHT-SUN ASSOCIATED
WITH A COLD FRONT...AND THEN A MORE MARGINAL EVENT SLATED FOR
MONDAY AS LOW PRESSURE LIFTS THROUGH THE TN/OH VALLEY PER THE
ECMWF. THIS IS UNLESS THE GFS/GGEM CONTINUE TO TREND A FLATTER
WAVE OUT TO SEA TO OUR SOUTH MISSING US COMPLETELY. WPC GRIDS SEEM
TO BE HEAVY HANDED ON THE ECMWF SOLUTIONS...BUT GIVEN UNCERTAINTY
INTRODUCED BY GFS/GGEM...WE HAVE SOFTENED THEM TO CHANCE POPS IN
THIS AREA FROM SUN-MON NGT. BEYOND THEN...WEAK WAVES AND PASSING
FLURRIES POSSIBLE THROUGH MID-WEEK.
OVERALL...TEMPERATURES WITHIN THE BROAD SWLY FLOW WILL BE NEAR TO
ABOVE LATE DECEMBER NORMALS.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
MILD MOIST CONDITIONS WILL REMAIN ACROSS THE AREA TONIGHT WITH
MVFR AND IFR CIGS AND MOSTLY MVFR TO VFR VSBYS THROUGH THE
EVENING. CONDITIONS WILL PROBABLY LOWER A BIT OVERNIGHT WITH MANY
AREAS LIKELY EXPERIENCING IFR CONDITIONS OVERNIGHT INTO WEDNESDAY
MORNING. PRECIPITATION WILL BE IN THE FORM OF SPOTTY LIGHT DRIZZLE
LATE TONIGHT... THEN STEADIER RAIN WILL OVERSPREAD THE AREA FROM
THE SOUTH FROM 10-15Z WEDNESDAY MORNING. CONDITIONS WILL BE MAINLY
MVFR IN RAIN THROUGH THE DAY WEDNESDAY. SOME LOW LEVEL WIND SHEAR
WILL DEVELOP WEDNESDAY AFTERNOON WITH SOUTHERLY FLOW INCREASING TO
40-45 KTS AT 2000 FEET WHILE WINDS NEAR THE SURFACE REMAIN LIGHT
FROM THE SOUTHEAST.
OUTLOOK...
WED NGT...IFR. PERIODS OF RAIN.
THU...BECOMING VFR...AREAS MVFR. WINDY WITH SHOWERS.
FRI/SAT...VFR. CHC SHRA SAT.
SUN...MVFR/IFR. CHC RAIN OR SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...DJN
LONG TERM...JAB
AVIATION...JAB/MSE
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
700 PM EST TUE DEC 23 2014
.SYNOPSIS...
A WEAK WARM FRONT WILL MOVE THROUGH EASTERN NORTH CAROLINA TONIGHT.
A STRONG COLD FRONT WILL APPROACH THE REGION WEDNESDAY...MOVING
THROUGH WEDNESDAY NIGHT. HIGH PRESSURE WILL BUILD OVER THE AREA
LATE THURSDAY THROUGH SATURDAY. ANOTHER COLD FRONT WILL APPROACH
THE AREA SUNDAY.
&&
.NEAR TERM /TONIGHT/...
AS OF 7 PM TUE...NO MAJOR CHANGES TO EVENING UPDATE. FCST ON TRACK
WITH WIDESPREAD SHOWER ACTIVITY APPROACHING E NC FROM THE SOUTH
AND WEST. HAVE ADDED ISO MENTION OF THUNDER TO GRIDS AS ELEVATED
INSTABILITY ON THE INCREASE THIS EVENING PER RUC ANALYSIS AND SPC
MESO. HAVE ALSO ISSUED AN SPS FOR INLAND ZONES FOR FOG THREAT.
MOST AREAS WILL REMAIN ABOVE A HALF MILE IN VISIBILITY SO NO DENSE
FOG ADVISORY EXPECTED...HOWEVER LOCALIZED AREAS WILL DROP TO BELOW
A QUARTER MILE AT TIMES SO SPS IS WARRANTED. STILL EXPECTING LOW
TEMPS TO BE REALIZED RIGHT AROUND NOW...THEN TEMPS WARM UP
OVERNIGHT WITH READINGS MOST AREAS INTO THE 60-65 DEGREE RANGE BY
WED MORNING.
PREVIOUS DISCUSSION...AS OF 315 PM TUE...LATEST SURFACE ANALYSIS
WEAK LOW OFF THE DELMARVA...WITH WEAK WARM FRONT LINGERING ALONG
THE NC COAST. LOW PRESSURE SYSTEM/UPPER TROUGH AND ASSOCIATED COLD
FRONT IN THE MID WEST WILL GRADUALLY PUSH WEST OVERNIGHT. WARM
FRONT WILL MOVE INLAND THROUGH THE AREA THIS EVENING...WITH WINDS
BECOMING SE/S. HIGH RES MODELS CONTINUE TO SHOW WIDESPREAD PRECIP
OVERSPREADING THE AREA FROM THE SW THIS EVENING...WITH BULK OF
COVERAGE CURRENTLY OVER SC/GA. LOCALLY HEAVY RAINFALL WILL BE
POSSIBLE MAINLY BTWN 03-08Z. MODELS CONTINUE TO SHOW A LULL IN
ACTIVITY AFTER 09Z. FEW LIGHTNING STRIKES SEEN OVER SE NC NEAR THE
WARM FRONT THIS AFTERNOON. DO NOT EXPECT TO SEE MUCH CONVECTIVE
TYPE PRECIP OVER THE AREA TONIGHT GIVEN STABLE
ENVIRONMENT...THOUGH DID ADD ISO MENTION OF TSTMS ALONG THE COAST
LATE. ANOTHER FORECAST CHALLENGE OVERNIGHT WILL BE POTENTIAL FOR
FOG DEVELOPMENT. AT THIS TIME DO NOT EXPECT FOG TO BE AS DENSE OR
WIDESPREAD AS LAST NIGHT AND TODAY WITH INCREASING SLY FLOW.
THOUGH WILL CONTINUE TO MENTION IT IN THE GRIDS. EXPECT TO SEE
NON-DIURNAL TEMP CURVE OVERNIGHT WITH INCREASING SLY FLOW AND
STRONG WAA. LOWS EARLY...WITH TEMPS RISING INTO THE UPPER 50S/LOW
60S BY EARLY WED MORNING.
&&
.SHORT TERM /WEDNESDAY/...
AS OF 315 PM TUE...UNSETTLED AND ACTIVE WX CONTINUES FOR CHRISTMAS
EVE ACROSS EASTERN NC. STRONG LOW PRESSURE SYSTEM OVER THE TN/OH
VALLEY REGION EARLY WED WILL LIFT NORTHWARD INTO THE GREAT LAKES
THROUGH THE DAY BECOMING VERTICALLY STACKED...AS ASSOCIATED COLD
FRONT MOVES THROUGH THE SE AND MID-ATLANTIC STATES. EASTERN NC
WILL REMAIN IN THE WARM SECTOR IN A HIGH SHEAR/LOW CAPE
ENVIRONMENT. THE MAIN CONCERN WILL BE THE POTENTIAL FOR STRONG TO
SEVERE THUNDERSTORMS. BASED ON THE HIGH RES MODELS COULD SEE LULL
IN PRECIP EARLY WED...WITH CHANCES INCREASING LATE MORNING AND
AFTERNOON AS CONVECTIVE LINE APPROACHES FROM THE SW. SURFACE BASED
INSTABILITY CONTINUES TO LOOKS VERY LIMITED BUT IF ANY INSTABILITY
IS REALIZED...AND GIVEN THE SHEAR PROFILES...THIS COULD MEAN A
SMALL CHANCE OF STRONG TO SEVERE STORMS WITH THE MAIN THREATS
BEING DAMAGING WIND GUSTS OR AN ISOLATED TORNADO. THIS SYSTEM ALSO
HAS THE POTENTIAL TO PRODUCE HEAVY RAINFALL AS PWAT VALUES RISE TO
NEAR CLIMO MAX...WITH THE GFS SHOWING PWATS AROUND 2 INCHES.
LOW LEVEL THICKNESS VALUES AND SLY FLOW SUPPORT ABOVE NORMAL
TEMPS WED WITH HIGHS IN THE UPPER 60S/LOWER 70S. COULD ALSO SEE
SOME SEA/ADVECTION FOG ALONG THE COAST...WITH BETTER CHANCES NORTH
OF HATTERAS...AS THE VERY WARM MOIST AIR TRAVELS OVER THE COOLER
NEAR SHORE SHELF WATERS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
AS OF 300 PM TUESDAY...12Z MODELS IN GOOD AGREEMENT WITH PATTERN
INTO THE WEEKEND...THEN GFS AND ECMWF DO CONTINUE TO DIVERGE ON
SUN-TUE PERIOD.
UPR LOW LIFTING OUT OF PLAINS THROUGH GREAT LAKES INTO ERN CANADA
WILL PUSH A POTENT SHRT WV TROF ACROSS AREA WED NIGHT INTO EARLY THU
ACCOMPANIED BY SFC COLD FRONT. MAIN CHANGE WITH THIS FCST PACKAGE
WAS TO INCREASE POPS OVER ERN SECTIONS LATE WED NIGHT WITH LINGERING
CHC POPS COAST THU MORNING. 12Z MODELS IN AGREEMENT ON SLIGHTLY
SLOWER UPR TROF PASSAGE.
HIGH SHEAR/LOW CAPE ISOLD SVR THREAT WILL CONTINUE WED EVENING AS
LATEST MODELS CONTINUE TO INDICATE VERY LIMITED SFC INSTABILITY BUT
STRONG WIND FIELDS. HEAVY RAIN A HIGHER PROBABILITY WITH PW NEAR 2
INCHES WITH DEEP MSTR BAND WED NIGHT.
DRYING CONDITIONS EXPECTED THU AFTN THROUGH SAT WITH RIDGING SFC AND
ALOFT. SFC HIGH BUILDING IN FROM SW WILL HAVE MODIFIED AIR MASS
FURTHER WARMED BY DOWNSLOPIN...THUS MIN TEMPS REMAINING ABOVE
FREEZING BOTH THU AND FRI NIGHTS AND HIGH TEMPS ABOVE NORMAL AS
WELL.
LEANED TO ECMWF AND WPC PROGS FOR SUN-TUE PERIOD AS GFS APPEARS TOO
FAST WITH TOO FAST WITH NEXT COLD FRONT PUSHING INTO AREA GIVEN
STRONG SFC AND UPR RIDGE IN PLACE ACROSS SE US. PREFERRED SOLUTION
WILL INDICATE COLD FRONT STALLING W AND N OF AREA...THEN MOVING
THROUGH MON NIGHT INTO EARLY TUE AS DEVELOPING SFC LOW MOVES ACROSS
TO N AND NE. KEPT SLIGHT CHC POPS ALL ZONES FOR SAT NIGHT WITH WAA
DEVELPING...THEN CHC POPS FOR SHOWERS SUN THROUGH MON NIGHT WITH
HIGHER POPS NW SUN AND SUN NIGHT. LINGERING SLGT CHC POPS FOR COAST
TUE MORNING...THEN DRY REST OF DAY BUT CONFIDENCE BELOW NORMAL LAST
HALF OF PERIOD.
TEMPS GENERALLY ABOVE NORMAL UNTIL ARCTIC AIR IS TAPPED AGAIN NEXT
TUESDAY.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM /THROUGH WEDNESDAY/...
AS OF 7 PM TUESDAY...HIGH CONFIDENCE IN PREVAILING LIFR/IFR
CONDITIONS THROUGH THE TAF PERIOD. LOW STRATUS WITH CEILINGS BELOW
1000FT WILL PERSIST THROUGH WEDNESDAY. VSBYS 1 MILE OR LESS
CONTINUE THROUGH MUCH OF TONIGHT. RAIN OVERSPREADS THE TAF SITES
AFTER 00Z. THE RAIN COULD BECOME LOCALLY HEAVY 03Z-09Z ACCORDING
TO HIGH RESOLUTION MODELS WITH IFR VISIBILITIES EXPECTED AGAIN
TONIGHT...IN RAIN AND FOG. THE RAIN COULD ACTUALLY HELP SCOUR OUT
ANY DENSE FOG THAT OCCURS THOUGH CIGS WILL STILL BE IN THE LIFR
RANGE THROUGH THE OVERNIGHT. COULD SEE A BRIEF LULL IN PRECIP
EARLY WED MORNING BEFORE SECONDARY AREA MOVES INTO THE AREA LATE
MORNING/AFTERNOON AHEAD OF THE COLD FRONT. ISOLATED TSTMS POSSIBLE
BOTH TONIGHT AND WEDNESDAY. SOUTHERLY WIND 10 TO 15 KT EXPECTED
WED MORNING AND AFTERNOON AND COULD GUST HIGHER ESP IF THERE ARE
ANY BREAKS IN THE CLOUDS.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 300 PM TUESDAY...LINGERING SUB-VFR CONDITIONS WITH WIDESPREAD
SHOWERS/ISOLD TSTMS WEDNESDAY NIGHT. GUSTY SW WINDS WILL BE SHIFTING
TO THE WEST LATE WED NIGHT AND THURSDAY AS COLD FRONT MOVES ACROSS.
DRY HIGH PRESSURE PRODUCING PREDOMINANT VFR CONDITIONS RETURNS TO
THE AREA BEHIND THE COLD FRONT THURSDAY THROUGH SATURDAY. SOME
SUB-VFR PSBL AGAIN SAT NIGHT AND SUNDAY AS WAA DEVELOPS AHEAD OF
NEXT FRONTAL SYSTEM.
&&
.MARINE...
SHORT TERM /THROUGH WEDNESDAY/...
AS OF 315 PM TUE...LATEST OBS SHOW WINDS NW TO NE GENERALLY 10KT OR
LESS...SLIGHTLY STRONGER 10-15KT ON THE OUTER PORTIONS OF THE
SOUTHERN WATERS WITH SEAS 2-4FT. WEAK WARM FRONT LINGERING ALONG
THE COAST WILL MOVE INLAND THROUGH THE WATERS TONIGHT...WITH WINDS
GRADUALLY VEERING BECOMING SE/SLY. PATCHY FOG WILL BE POSSIBLE
AGAIN OVERNIGHT INTO EARLY WED FOR THE WATERS AND SOUNDS...THOUGH
AT THIS TIME DO NOT THINK IT WILL BE AS DENSE OR WIDESPREAD AS
THIS MORNING GIVEN THE INCREASING SLY FLOW. A STRONG COLD FRONT
WILL APPROACH THE WATERS TONIGHT AND WEDNESDAY...AND MODELS IN
GOOD AGREEMENT WITH SLY WINDS INCREASING TO 15-25KT WITH GUSTS TO
30KT. WAVEWATCH AND LOCAL NWPS ALSO IN GOOD AGREEMENT SHOWING SEAS
BUILDING TO 4-6FT EARLY WED MORNING...THEN 5-8FT DURING THE
AFTERNOON.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 300 PM TUESDAY...HAZARDOUS MARINE CONDITIONS ARE EXPECTED INTO
THURSDAY NIGHT AS A STRONG COLD FRONT MOVES ACROSS THE WATERS EARLY
THURSDAY. SOUTHERLY WINDS 20 TO 30 KT WEDNESDAY EVENING WILL BECOME
WESTERLY 20 TO 25 KT LATE WEDNESDAY NIGHT AND THURSDAY BEHIND THE
FRONT. WINDS WILL BECOME NORTHWEST AND DIMINISH TO 15 TO 20 KT
THURSDAY NIGHT THEN BECOME NORTHERLY 10 KT OR LESS FRIDAY AS HIGH
PRESSURE BUILDS OVER THE WATERS. WINDS WILL BECOME SOUTHWEST
SATURDAY INTO SUNDAY AND INCREASE TO 10 TO 15 KT LATE AHEAD OF
ANOTHER APPROACHING COLD FRONT.
SEAS WILL PEAK AT 7-11 FT WEDNESDAY NIGHT..PER PREFERRED LOCAL
NWPS..THEN SUBSIDE BELOW 6 FT THURSDAY NIGHT AND 2 TO 3 FT FRIDAY
AND SATURDAY. SEAS BUILDING AGAIN TO 3-4 FT SUNDAY.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 AM WEDNESDAY TO 3 PM EST THURSDAY
FOR AMZ130-131-135>137.
SMALL CRAFT ADVISORY FROM 5 AM WEDNESDAY TO 1 AM EST FRIDAY
FOR AMZ152-154.
SMALL CRAFT ADVISORY FROM 5 AM WEDNESDAY TO 10 PM EST THURSDAY
FOR AMZ150-156-158.
&&
$$
SYNOPSIS...CQD/DAG
NEAR TERM...CQD/TL
SHORT TERM...CQD
LONG TERM...BTC/JME
AVIATION...JME/TL/CQD
MARINE...JME/CQD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
307 PM EST MON DEC 22 2014
.SYNOPSIS...
MOISTURE WILL OVERRUN A COOL SURFACE AIR MASS THE REMAINDER OF THE
DAY LEADING TO PERIODS OF LIGHT RAIN. THIS AIR MASS LIFTS OUT ON
TUESDAY CLEARING THE PATH FOR WARMER TEMPERATURES AND EVEN MORE
MOISTURE. A COLD FRONT MAY ADD SOME THUNDER WEDNESDAY AND WEDNESDAY
NIGHT. DRY AND SEASONABLE WEATHER RETURNS FOR CHRISTMAS AND THE
DAYS THAT FOLLOW.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 3 PM MONDAY...THE COASTAL FRONT IS STILL LOCK IN ITS LOCATION
OFF THE COAST AND EXPECT IT TO REMAIN OFF THE COAST THROUGHOUT THE
OVERNIGHT PERIOD. OF THE 2 U.S. DETERMINISTIC MODELS THE NAM APPEARS
TO BE HANDLING THIS FEATURE THE BEST BY KEEPING OFF THE COAST
LONGER. THE GFS CONTINUES WITH IT INSTANCE TO BRING THE BOUNDARY
CLOSER TO THE COAST OVERNIGHT. WITH PAST HISTORY OF MODELS AND IT
POOR HANDLING OF COASTAL FRONTS WILL SIDE WITH THE SLOWER NAM MODEL.
THE LATEST HRRR MODEL...16 UTC...IS DEPICTING TWO WAVE PASSING
ACROSS THE FORECAST AREA THROUGH 06 UTC. ONE FOR THIS AFTERNOON AND
A SECOND BEFORE MIDNIGHT. THE BEST CHANCES APPEAR IN THE EASTERN
HALF OF THE FORECAST AREA.
WITH THE COLD AIR DAMMING IN PLACE DO NOT EXPECT TEMPERATURE TO
BUDGE OVERNIGHT WITH LOW CLOUDS AND A LIGHT NORTH WINDS.
TEMPERATURES ARE EXPECTED TO RANGE BETWEEN 42 AND 45 DEGREES.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...SHORT TERM WILL BE QUITE ACTIVE WITH A
COMPLEX STORM SYSTEM AFFECTING THE EASTERN CONUS. PERIOD BEGINS
WITH HIGH PRESSURE RIDGING DOWN THE COAST AND FRONT STALLED
OFFSHORE. AS IS TYPICAL THE GUIDANCE WANTS TO MOVE THE FRONT
ONSHORE EARLY TUE...BUT THIS PROBABLY WONT HAPPEN SAVE FOR THE
COAST UNTIL LATE IN THE DAY TUE OR EVEN TUE EVENING. THE RESULT
WILL BE CONTINUATION OF LIGHT PATCHY RAIN ALONG WITH POTENTIAL FOR
SOME EMBEDDED ELEVATED CONVECTION. THE FRONT AND ITS LOCATION ON
TUE WILL DETERMINE HIGH TEMPERATURE GRADIENT...WHICH IS LIKELY TO
BE SIGNIFICANT. ALONG THE COAST MID TO UPPER 60S IS POSSIBLE WHILE
WEST OF I-95 HIGHS MAY STRUGGLE TO REACH 50.
COASTAL FRONT PUSHES NORTHWEST OF THE AREA TUE NIGHT WITH STRONG
WARM ADVECTION AND IMPRESSIVE LOW LEVEL JETTING IN THE AREA.
FORECAST SOUNDINGS SHOW 45 KT DEVELOPING BY WED MORNING WHICH WILL
KEEP LOWS ABOVE TO WELL ABOVE CLIMO. INLAND AREAS MAY END UP WITH
TUE HIGHS AND TUE NIGHT LOWS BEING THE SAME OR WITHIN A DEGREE OF
EACH OTHER. FORECAST SOUNDINGS SHOW SOME WEAK INSTABILITY ABOVE
900MB ALONG WITH PVA AHEAD OF SHORTWAVES EJECTED NORTHEAST FROM THE
BASE OF THE 5H TROUGH. ALTHOUGH HARD TO PIN DOWN A FAVORED
LOCATION/TIME TUE NIGHT SHOULD BE FAIRLY ACTIVE AND WILL MAINTAIN
INHERITED CATEGORICAL POP. ALTHOUGH THERE WILL BE ELEVATED
INSTABILITY AND IMPRESSIVE JETTING DO NOT THINK DAMAGING WINDS WILL
BE AN ISSUE. THE BOUNDARY LAYER IS QUITE STABLE SO WHILE SURFACE
WINDS WILL BE GUSTY DUE TO THE ENHANCED GRADIENT DO NOT FORESEE
SIGNIFICANT SEVERE THREAT.
IMPRESSIVE WARM ADVECTION CONTINUES WED AHEAD OF THE APPROACHING
COLD FRONT. HIGHS WILL CLIMB INTO THE 70S IN A LOT OF AREAS DESPITE
CLOUD COVER. ONCE AGAIN THERE WILL BE STRONG LOW LEVEL JETTING AND
AN ABUNDANCE OF SHEAR BUT INSTABILITY WILL BE LACKING. FORECAST
SOUNDINGS PEAK MLCAPE VALUES BETWEEN 100 AND 200 J/KG WED AFTERNOON
WITH LOW LEVEL LAPSE RATES MARGINAL AT BEST. CONTINUE TO EXPECT
WIDESPREAD PRECIP BUT NOT AS CONFIDENT ON POTENTIAL FOR STRONG TO
SEVERE STORMS. STORM MOTIONS WILL BE ON THE ORDER OF 35 KT AND WITH
POTENTIAL FOR SOME CONVECTION CANNOT RULE OUT SEVERE WEATHER BUT IT
SEEMS LIKE A LONG SHOT AT THIS POINT...HENCE SPC HAVING MOST OF THE
FORECAST AREA IN MARGINAL RISK FOR DAY 3. DO THINK RAIN COULD BE
HEAVY AT TIMES WITH PRECIPITABLE WATER VALUES IN FORECAST SOUNDINGS
AROUND 2 INCHES. WORTH NOTING 2 INCHES WOULD BE RIGHT AROUND THE
HIGHEST EVER RECORDED FOR LATE DEC.
COLD FRONT MOVES ACROSS THE FORECAST AREA LATE WED NIGHT BRINGING AN
END TO PRECIP. LATE ARRIVAL/PASSAGE OF FRONT WILL NECESSITATE
KEEPING HIGH POP IN THE WED NIGHT PERIOD THOUGH BASED ON LATEST
TIMING THINK PRECIP WILL BE OVER IN MOST AREAS AROUND MIDNIGHT. THE
EXCEPTION WOULD BE THE NC COAST WHERE PRECIP MAY LINGER A FEW HOURS
AFTER MIDNIGHT. MID LEVEL TROUGH AXIS REMAINS WEST OF THE AREA INTO
THU KEEPING WHAT COLD AIR IS PRESENT WELL TO THE WEST. FORECAST
SOUNDINGS SHOW LOW LEVEL DRY AIR SPREADING OVER THE REGION BUT
MOISTURE ALOFT WILL KEEP CLOUD COVER IN PLACE THROUGH THE END OF THE
PERIOD. CLOUD COVER AND DEEP WESTERLY FLOW WILL KEEP WED NIGHT LOWS
ABOVE TO WELL ABOVE CLIMO.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 3 PM MONDAY...SUNSHINE WILL MAKE A REAPPEARANCE FINALLY ON
CHRISTMAS DAY. THE MID TO UPPER TROUGH JUST ENTERING THE CAROLINAS
THURS MORNING WILL PUSH THE COLD FRONT FARTHER OFF SHORE THROUGH THE
DAY LEAVING A DEEP W-NW FLOW OF DRIER AND SOMEWHAT COOLER AIR.
DEWPOINT TEMPS WILL DROP THROUGH THE DAY WITH A 20 PLUS DEGREE DROP
FROM PREVIOUS DAY. PCP WATER VALUES WILL DROP LESS THAN A HALF INCH
BY NOON AS COLUMN DRIES OUT. OVERALL EXPECT CLEARING THROUGH THE
MORNING WITH INCREASING SUNSHINE...GUSTY WINDS AND SEASONABLE TEMPS
CLOSER TO 60.
HIGH PRESSURE WILL BUILD UP FROM THE GULF COAST OVER THE SOUTHEAST
THURS INTO FRI. GUSTY WESTERLY WINDS ON THURS WILL LIGHTEN UP
BECOMING NEAR CALM THURS NIGHT AS THE CENTER OF THE HIGH SETTLES
OVER THE CAROLINAS. THE CLEAR SKIES AND LIGHT WINDS SHOULD ALLOW FOR
SOME DECENT RADIATIONAL COOLING AND TEMPS DOWN IN THE 30S THURS
NIGHT. A RETURN FLOW WILL SET UP THROUGH FRI AS RIDGE OF HIGH
PRESSURE SHIFTS OFF SHORE. THIS SOUTHERLY FLOW WILL ALLOW FOR A
RETURN OF MOISTURE AND WARMER TEMPS HEADING INTO THE WEEKEND. SHOULD
SEE AN INCREASE IN CLOUDS THROUGH SATURDAY AHEAD OF COLD FRONT
REACHING INTO THE CAROLINAS BY SAT NIGHT. BEST CHC OF PCP WILL COME
SAT NIGHT AS THE FRONT MOVES THROUGH. THIS COLD FRONT SHOULD PUSH
SOUTH THROUGH SUNDAY BUT THE FLOW ALOFT WILL REMAIN SW AS RIDGE
HOLDS ON TO OUR SOUTHEAST. THEREFORE WILL END UP WITH LOW CLOUDS
HANGING ON THROUGH THE START OF NEXT WEEK. TEMPS UP IN THE 60S ON
SATURDAY WILL BE BACK DOWN IN THE 50S MOST PLACES SUN AND MON
ESPECIALLY IF LOW CLOUDS HANG AROUND.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...CIGS REMAIN AOB 600-700 FEET EARLY THIS AFTERNOON. VSBYS
ARE VFR...BUT MVFR/IFR VSBYS ARE OCCURRING IN AREAS OF RAIN/BR AND
EMBEDDED SHOWERS MOVING NE MAINLY BETWEEN THE INLAND AND COASTAL
TERMINALS.
LITTLE IMPROVEMENT IS EXPECTED THIS AFTERNOON. KFLO/KLBT STAND THE
BEST CHANCE OF HAVING 700-900 FT CIGS/VFR VSBYS...BUT AN INCREASING
CHANCE OF RAIN WILL LIKELY DROP VSBYS AT TIMES TO MVFR THROUGH THIS
EVENING AT THOSE TERMINALS. EXPECT WORST CIGS/VSBYS AT THE COASTAL
TERMINALS THIS AFTERNOON AND EVENING WHERE PRECIPITATION IS MORE LIKELY.
THE PRECIPITATION ENDS THIS EVENING BUT A SATURATED LOW LEVEL AND
LOWERING LOW-LEVEL INVERSION SUGGEST CIGS/VSBYS APPROACHING 200 /
1/2 AT THE COASTAL TERMINALS. KFLO/KLBT SHOULD HAVE THE BETTER
FLIGHT CONDITIONS BUT STILL AOB 600/2.
MVFR CIGS MAY DEVELOP AT KCRE/KMYR LATE IN THE TAF PERIOD AS A WARM
FRONT APPROACHES...BUT THE REMAINING TERMINALS STAND A GOOD CHANCE
OF REMAINING AOB 600/2.
EXTENDED OUTLOOK...LIFR/IFR CIGS TUE WITH INCREASING CHANCES OF
SHOWERS. MVFR COASTAL TERMINALS LATER IN THE DAY. WED EXPECT
SHOWERS/MVFR AND GUSTY WINDS AHEAD OF A COLD FRONT. GUSTY WEST WINDS
AND VFR THU BEHIND THE FRONT. VFR FRI/SAT.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM MONDAY...THE COASTAL FRONT REMAINS EAST OF FRYING PAN
SHOALS AND THE BEST NUMERICAL MODEL KEEPS THIS FRONT TO THE EAST OF
THE COASTAL WATERS. THIS WILL PROVIDE FOR A NORTH TO NORTHEAST WIND
OF LESS THAN 15 KNOTS AND SEAS SHOULD RUN IN THE 2 TO 4 FOOT RANGE
OVERNIGHT. AS LONG AS THE COASTAL FRONT STAYS TO THE EAST OF THE
WATERS THERE SHOULD BOT BE A THREAT OF SEA FOG.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...COASTAL FRONT ACROSS THE WATERS TUE WILL MOVE
ONSHORE LATER IN THE DAY. TIMING THE FRONT...AND THE RESULTING
STRONG SOUTHERLY FLOW IS ALWAYS DIFFICULT. GUIDANCE IS USUALLY TOO
FAST TO MOVE THE FRONT INTO THE COLDER AIR AND TUE APPEARS TO BE
NO DIFFERENT. THUS CONTINUE FOLLOWING THE TREND FROM PREVIOUS
FORECASTS WITH MOVEMENT OF THE FRONT DELAYED UNTIL TUE
AFTERNOON/EVENING. THIS WILL KEEP WINDS OVER THE NEARSHORE WATERS
LIGHT AND VARIABLE TOMORROW BEFORE SOUTHERLY FLOW INCREASES TUE
NIGHT. SPEEDS LATE TUE NIGHT AND WED WILL BE INTO THE 20 TO 25 KT
RANGE AT TIMES...BUILDING SEAS ACROSS ALL WATERS OVER 6 FT. SCA
WILL BE NEEDED PROBABLY STARTING CLOSE TO MIDNIGHT AND LASTING
THROUGH WED AND WED NIGHT. LATE IN THE PERIOD THE COLD FRONT MOVES
ACROSS THE WATERS WITH OFFSHORE FLOW DEVELOPING. COLD ADVECTION IS
LACKING BUT GRADIENT REMAINS TIGHT AND SPEEDS WILL REMAIN NEAR THE
20 TO 25 KT RANGE THROUGH THE END OF THE PERIOD.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 PM MONDAY...COLD FRONT WILL SHIFT FARTHER OFF SHORE ON
THURS AS HIGH PRESSURE BUILDS UP FROM THE GULF COAST. GUSTY W-SW
WINDS EARLY THURS WILL VEER AROUND BECOMING WEST THROUGH THE DAY.
SEAS UP AROUND 5 TO 7 FT SHOULD FALL BELOW SCA THRESHOLDS BY THURS
AFTN WITH HIGHEST SEAS GETTING PUSHED FARTHER OFF SHORE IN STRONGER
W-NW FLOW BEHIND FRONT. WINDS WILL VEER FURTHER TO THE NW AND
LIGHTEN UP LATE THURS INTO FRI AS CENTER OF HIGH SHIFTS CLOSER
OVERHEAD. SEAS WILL BE DOWN TO 2 TO 4 FT BY THURS NIGHT AND DOWN TO
3 FT OR LESS THROUGH FRI AS HIGH PRESSURE MOVES OVERHEAD WITH MORE
VARIABLE WINDS EXPECTED.
HIGH PRESSURE WILL SHIFT FARTHER OFF SHORE ON SATURDAY WITH A RETURN
FLOW UNDER 15 KTS SETTING UP. A COLD FRONT WILL APPROACH SAT NIGHT
WITH WINDS VEERING AROUND AND INCREASING SLIGHTLY. THIS WILL PUSH
SEAS BACK UP CLOSER TO 3 TO 4 FT BY SUNDAY MORNING.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DRH
SHORT TERM...III
LONG TERM...RGZ
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1244 PM EST MON DEC 22 2014
.SYNOPSIS...
MOISTURE WILL OVERRUN A COOL SURFACE AIR MASS THE REMAINDER OF THE
DAY LEADING TO PERIODS OF LIGHT RAIN. THIS AIR MASS LIFTS OUT ON
TUESDAY CLEARING THE PATH FOR WARMER TEMPERATURES AND EVEN MORE
MOISTURE. A COLD FRONT MAY ADD SOME THUNDER WEDNESDAY AND WEDNESDAY
NIGHT. DRY AND SEASONABLE WEATHER RETURNS FOR CHRISTMAS AND THE
DAYS THAT FOLLOW.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1245 PM MONDAY...THE SURFACE LOW PRESSURE HAS SHIFTED
NORTHEASTWARD AND IS NOW OFF THE COAST BETWEEN NEAR CAPE
HATTERAS. THIS LOW HAS REINFORCED THE COOL NORTH WINDS AND IS
KEEPING THE COASTAL FRONT EAST OF FRYING PAN SHOALS. THE 12 UTC
NAM/GFS BOTH SHOWS THE COASTAL FRONT REMAINING OFF THE COAST UNTIL
TUESDAY MORNING.
ANOTHER WAVE OF IS MOVING UP THE COAST AND THE LATEST HRRR IS SHOWING
THE PRECIPITATION MAINLY TO THE SOUTH OF THE FORECAST AREA MOVING ACROSS
THIS AFTERNOON AND MAINLY EAST OF A KINGSTREE TO ELIZABETHTOWN
LINE. SO HIGH POPS TO THE EAST OF THE LINE AND CHANCE OF POPS TO
THE WEST.
WITH COLD AIR DAMMING IN PLACE AND CLOUDY SKIES ALL DAY EXPECTED
THE HIGHS WILL ONLY REACH 42-46 INLAND TO 47-49 AT THE BEACHES.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM MONDAY...VERY ACTIVE WEATHER EXPECTED FOR THE DURATION OF
THE PERIOD. WEDGE WILL FINALLY BE BREAKING DOWN ON TUESDAY. THE
SPEED AT WHICH THIS OCCURS, WHICH IS NOTORIOUSLY DIFFICULT TO MODEL,
WILL MODULATE HIGH TEMPS. CURRENT FCST LEANS MORE ON THE SLOWER WRF
KEEPING MID 50S INLAND WHILE COASTAL LOCALES GET INTO MID/UPPER 60S.
DEEP SWRLY FLOW OF MOISTURE TO BRING PLENTY OF CLOUDS AND OCCASIONAL
RAIN FROM TIME TO TIME. PINNING DOWN WHERE RAIN WILL BE HEAVIEST IS
DIFFICULT AT THIS TIME. RAINFALL RATES TO INCREASE TUESDAY NIGHT
INTO WEDNESDAY AS STRONGER FLOW AND DYNAMICS SPREAD ACROSS THE
REGION WHILE COLD FRONT APPROACHES FROM THE NORTH AND WEST. THE
STRONGER RESULTING FLOW WILL BRING EVEN MILDER AIR INTO THE COASTAL
PLAIN AND HIGHS IN THE 70S APPEAR LIKELY DESPITE THE CLOUDS AND
RAIN. DESPITE THE WARMTH FORECAST SOUNDINGS SHOW SUCH POOR LAPSE
RATES THAT INSTABILITY IS REALLY GOING TO BE TOUGH TO COME BY, MAYBE
ENOUGH ENOUGH TO WORRY ABOUT HSLC SETUP. HAVE LEFT ISO THUNDER AS
SOME FAIRLY STRONG VERTICAL MOTION MAY IMPACT THE REGION LATE IN THE
PERIOD. WEDNESDAY NIGHT`S LOWS MAY BE VERY MILD LIKE TUESDAY NIGHT
SAVE FOR SOME COLD ADVECTION RELATED TO FROPA TOWARDS DAYBREAK
THURSDAY. SIMILARLY RAIN WILL BE RAPIDLY SHUTTING OFF FROM WEST TO
EAST LATE WEDNESDAY NIGHT...THE EXACT TIMING LIKELY NEEDING OF SOME
REFINEMENT IN FUTURE FORECASTS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...CHRISTMAS AND THE FEW DAYS THAT FOLLOW WILL
FEATURE A RETURN OF SUNSHINE...NOT SEEN IN QUITE A WHILE. ALSO SINCE
THE UPPER WAVE DRIVING THE FRONT THROUGH NOW RETAINS A DEFINED
POSITIVE TILT THE COLD ADVECTION APPEARS QUITE TEMPERED AND THE
HOLIDAY WEEKEND NO LONGER SEEMS TO OFFER UP UNSEASONABLY COOL
TEMPERATURES IN FAVOR OF SEASONABLE WEATHER IF NOT A FEW DEGREES
ABOVE. MOISTURE MAY BE ON THE RISE BY SUNDAY AS A WEAK COLD FRONT
APPROACHES IN A STILL RATHER LOW AMPLITUDE PATTERN ALOFT.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...CIGS REMAIN AOB 600-700 FEET EARLY THIS AFTERNOON. VSBYS
ARE VFR...BUT MVFR/IFR VSBYS ARE OCCURRING IN AREAS OF RAIN/BR AND
EMBEDDED SHOWERS MOVING NE MAINLY BETWEEN THE INLAND AND COASTAL
TERMINALS.
LITTLE IMPROVEMENT IS EXPECTED THIS AFTERNOON. KFLO/KLBT STAND THE
BEST CHANCE OF HAVING 700-900 FT CIGS/VFR VSBYS...BUT AN INCREASING
CHANCE OF RAIN WILL LIKELY DROP VSBYS AT TIMES TO MVFR THROUGH THIS
EVENING AT THOSE TERMINALS. EXPECT WORST CIGS/VSBYS AT THE COASTAL
TERMINALS THIS AFTERNOON AND EVENING WHERE PRECIPITATION IS MORE LIKELY.
THE PRECIPITATION ENDS THIS EVENING BUT A SATURATED LOW LEVEL AND
LOWERING LOW-LEVEL INVERSION SUGGEST CIGS/VSBYS APPROACHING 200 /
1/2 AT THE COASTAL TERMINALS. KFLO/KLBT SHOULD HAVE THE BETTER
FLIGHT CONDITIONS BUT STILL AOB 600/2.
MVFR CIGS MAY DEVELOP AT KCRE/KMYR LATE IN THE TAF PERIOD AS A WARM
FRONT APPROACHES...BUT THE REMAINING TERMINALS STAND A GOOD CHANCE
OF REMAINING AOB 600/2.
EXTENDED OUTLOOK...LIFR/IFR CIGS TUE WITH INCREASING CHANCES OF
SHOWERS. MVFR COASTAL TERMINALS LATER IN THE DAY. WED EXPECT
SHOWERS/MVFR AND GUSTY WINDS AHEAD OF A COLD FRONT. GUSTY WEST WINDS
AND VFR THU BEHIND THE FRONT. VFR FRI/SAT.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1245 PM MONDAY...THE COASTAL FRONT REMAINS EAST OF FRYING
PAN SHOALS AND AND THE LOW THAT PAST JUST EAST OF THE WATERS HAS
SHIFTED NORTHEAST OF CAPE HATTERAS. THE WINDS ARE NORTHERLY AND
ARE AT 10 TO 15 KNOTS. THE SEAS HAVE DROPPED N A FOOT TO 4.5 FEET AT
41110 AND 5 FEET AT 41013. WINDS WILL REMAIN FROM THE NORTH AND AT
OR BELOW 15 KNOTS THROUGH THE NIGHT.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...TUESDAY CHARACTERIZED BY WEAKENING WEDGE OF HIGH
PRESSURE OVER LAND. THE SPEED AT WHICH THIS OCCURS IS ALWAYS A BIT
UNCERTAIN AND THIS WILL AFFECT HOW QUICKLY LOCAL WINDS VEER AND
INCREASE IN SPEED. HAVE OPTED FOR THE SLOWER MODEL SOLUTION WHICH
WILL KEEP THE MAIN DETERIORATION OF CONDITIONS OFF UNTIL TUESDAY
NIGHT. AT THIS TIME THE SSWRLY FLOW REALLY BECOMES ESTABLISHED IN A
STRENGTHENING STATE AS LOW LEVEL WIND FIELDS CRANK UP AND A COLD
FRONT AND STRONG UPPER TROUGH APPROACH. SMALL CRAFT ADVISORY
EXPECTED BY TUES NIGHT. WIND AND SEAS ONLY INCREASE FROM THERE AS
THE APPROACHING BOUNDARY TIGHTENS THE GRADIENT AND THE APPROACH OF
THE UPPER WAVE STRENGTHENS LOW LEVEL WIND FIELDS. FROPA EXPECTED
TOWARDS THE END OF THE PERIOD WITH AN ABRUPT WIND VEER.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM MONDAY...THE LONG TERM STARTS OFF WITH SMALL CRAFT
ADVISORY FLAGS FLYING JUST FOLLOWING VIGOROUSLY DRIVEN COLD FRONT.
HOWEVER THE COLD SURGE ITSELF IS RATHER UNIMPRESSIVE AND WINDS AND
SEAS SHOULD BOTH DROP OFF RATHER NICELY AS THE DAY WEARS ON. TOUGH
TO RULE OUT A PERIOD OF SCEC THOUGH AS THE SHARP WIND SHIFT COULD
LEAD TO RATHER STEEP WAVE FACES EVEN AS THEIR OVERALL HEIGHT
DECREASES. FRIDAY BRINGS A LIGHT OFFSHORE FLOW AS HIGH PRESSURE
SLOWLY BUILDS IN FROM THE WEST.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HAWKINS
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
942 PM CST TUE DEC 23 2014
.UPDATE...
ISSUED AT 932 PM CST TUE DEC 23 2014
CLEARING SKIES WEST RESULTING SOME PATCHY FOG. ADDED THIS TO THE
FORECAST. INCREASING HIGH CLOUDS LATER TONIGHT SHOULD LIMIT THE
EXTENT OF THE FOG HOWEVER. ALSO LOWERED MIN TEMPS ABOUT 5 - 7 DEGREES
SOUTHWEST.
UPDATE ISSUED AT 634 PM CST TUE DEC 23 2014
ADDED A SLIGHT CHANCE FOR SNOW AND FREEZING DRIZZLE ACROSS
NORTHWEST AND CENTRAL NORTH DAKOTA FOR THE EARLY EVENING HOURS.
RADAR RETURNS SUGGEST LIGHT PRECIP SHOWING UP BETWEEN BISMARCK AND
MINOT AS OF 630 PM CST. BUFKIT SOUNDINGS SHOW A LACK OF ICE
CRYSTALS TO ALLOWING SUPER COOLER WATER TO EXIST. THIS THROUGH 9
PM CST. REMAINDER OF THE FORECAST LOOKS GOOD.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 245 PM CST TUE DEC 23 2014
THE MAIN CONCERN IN THE SHORT WILL BE LINGERING LIGHT SNOW
CHANCES THIS AFTERNOON/EVENING...WITH CHANCES FOR RAIN OR SNOW ON
WEDNESDAY.
AFTERNOON REGIONAL RADAR MOSAIC SHOWS LIGHT SNOW ACROSS PARTS OF
WESTERN AND CENTRAL NORTH DAKOTA. THE SNOW HAS DIMINISHED IN
COVERAGE OVER THE PAST COUPLE HOURS...AND SHORT TERM MODELS
SUPPORT THAT TREND. WILL CARRY ONLY SMALL POPS WITH LITTLE TO NO
ADDITIONAL SNOW ACCUMULATION EXPECTED.
CONSIDERED ADDING PATCHY FOG IN THE WEST IN PROXIMITY TO A SURFACE
RIDGE AXIS. THE LATEST HRRR INDICATES THERE IS A CHANCE OF REDUCED
VISIBILITIES LATE TONIGHT INTO EARLY WEDNESDAY...BUT WAS NOT QUITE
CONFIDENT ENOUGH TO PUT IT IN YET. WILL LET LATER SHIFTS MONITOR
AND ADD IF NECESSARY.
H85 WARM AIR ADVECTION INCREASES WEDNESDAY WITH MODELS DIFFERING
IN REGARDS TO THE AREAL COVERAGE OF PRECIPITATION ASSOCIATED WITH
IT. THE SREF GENERALLY SUPPORTS KEEPING THE PRIMARY PRECIPITATION
CHANCES CONFINED TO NORTHERN PARTS OF THE STATE THROUGH WEDNESDAY
AFTERNOON...WHILE THE DETERMINISTIC NAM/GFS/ECMWF BRING CHANCES
FARTHER SOUTH. HAVE EXPANDED SLIGHT CHANCE POPS SOUTHWARD TO
ACKNOWLEDGE THE DETERMINISTIC SOLUTIONS...WHICH ALSO LINES UP WITH
THE H85 WARM AIR ADVECTION. PRECIPITATION TYPE WILL ALSO BE A
CONCERN WITH H85 TEMPERATURES RISING ABOVE ZERO DEGREES CELSIUS IN
THE SOUTHWEST. THE GOOD NEWS IS SURFACE TEMPERATURES ALSO WARM
ABOVE FREEZING IN THAT AREA...BUT IT WILL BE SOMETHING TO WATCH IN
REGARDS TO PRECIPITATION TYPE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 245 PM CST TUE DEC 23 2014
FOCUS IN THE LONG TERM IS ON THE LARGE SCALE UPPER LEVEL TROUGH
MOVING ACROSS THE CENTRAL CONUS THURSDAY INTO THE WEEKEND AND THE
COOLING TREND COMING THIS WEEKEND.
THE 12 UTC MODEL GUIDANCE IS IN GOOD AGREEMENT ON THE LARGE SCALE
PATTERN...PROGRESSING A DEEP UPPER LEVEL TROUGH FROM THE ROCKIES
EARLY THURSDAY TO THE GREAT LAKES REGION SATURDAY. FOR THE NORTHERN
PLAINS THE 12 UTC MODEL GUIDANCE SHOWS THE MAJORITY OF PRECIPITATION
FALLING ACROSS SOUTHEASTERN MONTANA AS WELL AS NORTHERN AND WESTERN
SOUTH DAKOTA WEDNESDAY NIGHT THROUGH FRIDAY...WITH ONLY MINOR
ACCUMULATIONS ACROSS SOUTHERN NORTH DAKOTA. HOWEVER THE 12 UTC RUNS
OF THE NAM AND GEM-NHEM SHOW PRECIPITATION FALLING FURTHER NORTH
ALONG AND SOUTH OF THE I-94 CORRIDOR IN WESTERN AND CENTRAL NORTH
DAKOTA WEDNESDAY NIGHT THROUGH THURSDAY MORNING. WITH THAT SAID
THESE LATEST 12 UTC RUNS ARE OUTLIERS WITH PREVIOUS MODEL RUNS AND
THE CURRENT 12 UTC RUNS OF THE GFS AND ECMWF. WILL HAVE TO WATCH TO
SEE IF THE HEAVIER PRECIPITATION SOLUTIONS OF THE NAM AND GEM-NHEM
CONTINUE OVER THE NEXT FEW MODELS RUNS...AS THEY SUGGEST BETWEEN 2
AND 4 INCHES COULD FALL OVER THE PERIOD WHICH MAY PROMPT HEADLINES.
HOWEVER...AT THIS TIME WENT WITH A MODEL BLEND FOR THE FORECAST AND
THINKING ONLY AROUND AN INCH TO TWO OF SNOW IN THE SOUTHWEST WITH
GENERALLY LESS THAN AN INCH ELSEWHERE...WHICH DOES NOT REQUIRE ANY
HEADLINES.
PRECIPITATION TYPE WEDNESDAY NIGHT THROUGH FRIDAY APPEARS TO BE ALL
SNOW. MID LEVELS SHOULD BE MOIST ENOUGH FOR ICE CRYSTALS AND
TEMPERATURE PROFILES WILL BE BELOW FREEZING SO THAT NO MELTING
OCCURS. SOME FREEZING DRIZZLE IS POSSIBLE AT TIMES THURSDAY NIGHT AS
THE SYSTEM MOVES SOUTHEAST AND MID LEVELS DRY OUT...HOWEVER
ACCUMULATION WOULD BE MINOR AND ANY PERIOD OF FREEZING DRIZZLE WOULD
BE BRIEF. THUS ONLY MENTION OF SNOW IN THE GRIDS FOR NOW.
ARCTIC AIR WILL FILTER IN BEHIND THIS SYSTEM WITH HIGHS DROPPING
FROM THE 20S CHRISTMAS DAY TO THE SINGLE DIGITS NORTH ON FRIDAY AND
TEENS ELSEWHERE. WIND CHILLS SUNDAY NIGHT AND MONDAY NIGHT WILL BE
VERY COLD. CURRENT FORECAST HAS WIND CHILLS APPROACHING 25 BELOW
ZERO ACROSS THE NORTHERN HALF OF THE STATE EARLY MONDAY MORNING AND
DROPPING TO 25 BELOW ZERO TO 35 BELOW ZERO ACROSS MUCH OF THE STATE
MONDAY NIGHT INTO TUESDAY MORNING.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 634 PM CST TUE DEC 23 2014
WIDESPREAD MVFR WILL CONTINUE FROPM KBIS-KMOT-KISN TONIGHT. GRADUAL
CLEARING FROM WEST TO EAST WILL REACH KBIS-KMOT LINE AFTER 10Z/4
AM CST. KISN-KDIK EXPECTED TO BE VFR. MENTIONED PATCHY GROUND FOG
VICINITY KISN-KDIK-KMOT AS CLOUDS BREAK UP TONIGHT BUT SOME
UNCERTAINTY SO DID NOT LOWER VISIBILITY THERE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...CK
LONG TERM...MM
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
650 PM CST TUE DEC 23 2014
.UPDATE...
ISSUED AT 634 PM CST TUE DEC 23 2014
ADDED A SLIGHT CHANCE FOR SNOW AND FREEZING DRIZZLE ACROSS
NORTHWEST AND CENTRAL NORTH DAKOTA FOR THE EARLY EVENING HOURS.
RADAR RETURNS SUGGEST LIGHT PRECIP SHOWING UP BETWEEN BISMARCK AND
MINOT AS OF 630 PM CST. BUFKIT SOUNDINGS SHOW A LACK OF ICE
CRYSTALS TO ALLOWING SUPER COOLER WATER TO EXIST. THIS THROUGH 9
PM CST. REMAINDER OF THE FORECAST LOOKS GOOD.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 245 PM CST TUE DEC 23 2014
THE MAIN CONCERN IN THE SHORT WILL BE LINGERING LIGHT SNOW
CHANCES THIS AFTERNOON/EVENING...WITH CHANCES FOR RAIN OR SNOW ON
WEDNESDAY.
AFTERNOON REGIONAL RADAR MOSAIC SHOWS LIGHT SNOW ACROSS PARTS OF
WESTERN AND CENTRAL NORTH DAKOTA. THE SNOW HAS DIMINISHED IN
COVERAGE OVER THE PAST COUPLE HOURS...AND SHORT TERM MODELS
SUPPORT THAT TREND. WILL CARRY ONLY SMALL POPS WITH LITTLE TO NO
ADDITIONAL SNOW ACCUMULATION EXPECTED.
CONSIDERED ADDING PATCHY FOG IN THE WEST IN PROXIMITY TO A SURFACE
RIDGE AXIS. THE LATEST HRRR INDICATES THERE IS A CHANCE OF REDUCED
VISIBILITIES LATE TONIGHT INTO EARLY WEDNESDAY...BUT WAS NOT QUITE
CONFIDENT ENOUGH TO PUT IT IN YET. WILL LET LATER SHIFTS MONITOR
AND ADD IF NECESSARY.
H85 WARM AIR ADVECTION INCREASES WEDNESDAY WITH MODELS DIFFERING
IN REGARDS TO THE AREAL COVERAGE OF PRECIPITATION ASSOCIATED WITH
IT. THE SREF GENERALLY SUPPORTS KEEPING THE PRIMARY PRECIPITATION
CHANCES CONFINED TO NORTHERN PARTS OF THE STATE THROUGH WEDNESDAY
AFTERNOON...WHILE THE DETERMINISTIC NAM/GFS/ECMWF BRING CHANCES
FARTHER SOUTH. HAVE EXPANDED SLIGHT CHANCE POPS SOUTHWARD TO
ACKNOWLEDGE THE DETERMINISTIC SOLUTIONS...WHICH ALSO LINES UP WITH
THE H85 WARM AIR ADVECTION. PRECIPITATION TYPE WILL ALSO BE A
CONCERN WITH H85 TEMPERATURES RISING ABOVE ZERO DEGREES CELSIUS IN
THE SOUTHWEST. THE GOOD NEWS IS SURFACE TEMPERATURES ALSO WARM
ABOVE FREEZING IN THAT AREA...BUT IT WILL BE SOMETHING TO WATCH IN
REGARDS TO PRECIPITATION TYPE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 245 PM CST TUE DEC 23 2014
FOCUS IN THE LONG TERM IS ON THE LARGE SCALE UPPER LEVEL TROUGH
MOVING ACROSS THE CENTRAL CONUS THURSDAY INTO THE WEEKEND AND THE
COOLING TREND COMING THIS WEEKEND.
THE 12 UTC MODEL GUIDANCE IS IN GOOD AGREEMENT ON THE LARGE SCALE
PATTERN...PROGRESSING A DEEP UPPER LEVEL TROUGH FROM THE ROCKIES
EARLY THURSDAY TO THE GREAT LAKES REGION SATURDAY. FOR THE NORTHERN
PLAINS THE 12 UTC MODEL GUIDANCE SHOWS THE MAJORITY OF PRECIPITATION
FALLING ACROSS SOUTHEASTERN MONTANA AS WELL AS NORTHERN AND WESTERN
SOUTH DAKOTA WEDNESDAY NIGHT THROUGH FRIDAY...WITH ONLY MINOR
ACCUMULATIONS ACROSS SOUTHERN NORTH DAKOTA. HOWEVER THE 12 UTC RUNS
OF THE NAM AND GEM-NHEM SHOW PRECIPITATION FALLING FURTHER NORTH
ALONG AND SOUTH OF THE I-94 CORRIDOR IN WESTERN AND CENTRAL NORTH
DAKOTA WEDNESDAY NIGHT THROUGH THURSDAY MORNING. WITH THAT SAID
THESE LATEST 12 UTC RUNS ARE OUTLIERS WITH PREVIOUS MODEL RUNS AND
THE CURRENT 12 UTC RUNS OF THE GFS AND ECMWF. WILL HAVE TO WATCH TO
SEE IF THE HEAVIER PRECIPITATION SOLUTIONS OF THE NAM AND GEM-NHEM
CONTINUE OVER THE NEXT FEW MODELS RUNS...AS THEY SUGGEST BETWEEN 2
AND 4 INCHES COULD FALL OVER THE PERIOD WHICH MAY PROMPT HEADLINES.
HOWEVER...AT THIS TIME WENT WITH A MODEL BLEND FOR THE FORECAST AND
THINKING ONLY AROUND AN INCH TO TWO OF SNOW IN THE SOUTHWEST WITH
GENERALLY LESS THAN AN INCH ELSEWHERE...WHICH DOES NOT REQUIRE ANY
HEADLINES.
PRECIPITATION TYPE WEDNESDAY NIGHT THROUGH FRIDAY APPEARS TO BE ALL
SNOW. MID LEVELS SHOULD BE MOIST ENOUGH FOR ICE CRYSTALS AND
TEMPERATURE PROFILES WILL BE BELOW FREEZING SO THAT NO MELTING
OCCURS. SOME FREEZING DRIZZLE IS POSSIBLE AT TIMES THURSDAY NIGHT AS
THE SYSTEM MOVES SOUTHEAST AND MID LEVELS DRY OUT...HOWEVER
ACCUMULATION WOULD BE MINOR AND ANY PERIOD OF FREEZING DRIZZLE WOULD
BE BRIEF. THUS ONLY MENTION OF SNOW IN THE GRIDS FOR NOW.
ARCTIC AIR WILL FILTER IN BEHIND THIS SYSTEM WITH HIGHS DROPPING
FROM THE 20S CHRISTMAS DAY TO THE SINGLE DIGITS NORTH ON FRIDAY AND
TEENS ELSEWHERE. WIND CHILLS SUNDAY NIGHT AND MONDAY NIGHT WILL BE
VERY COLD. CURRENT FORECAST HAS WIND CHILLS APPROACHING 25 BELOW
ZERO ACROSS THE NORTHERN HALF OF THE STATE EARLY MONDAY MORNING AND
DROPPING TO 25 BELOW ZERO TO 35 BELOW ZERO ACROSS MUCH OF THE STATE
MONDAY NIGHT INTO TUESDAY MORNING.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 634 PM CST TUE DEC 23 2014
WIDESPREAD MVFR WILL CONTINUE FROPM KBIS-KMOT-KISN TONIGHT. GRADUAL
CLEARING FROM WEST TO EAST WILL REACH KBIS-KMOT LINE AFTER 10Z/4
AM CST. KISN-KDIK EXPECTED TO BE VFR. MENTIONED PATCHY GROUND FOG
VICINITY KISN-KDIK-KMOT AS CLOUDS BREAK UP TONIGHT BUT SOME
UNCERTAINTY SO DID NOT LOWER VISIBILITY THERE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...CK
LONG TERM...MM
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1221 PM CST MON DEC 22 2014
.UPDATE...
ISSUED AT 1221 PM CST MON DEC 22 2014
WINTER WEATHER CONTINUES WITH IMPACTS ON TRAVEL TODAY. MAIN
CHANGES WERE TO ISSUE A WINTER WEATHER ADVISORY FOR THE JAMES
RIVER VALLEY INTO FAR SOUTH CENTRAL NORTH DAKOTA FOR THE
ANTICIPATED TROWAL INDUCED SNOW BAND STARTING TO DEVELOP ACROSS
THE SOUTHEASTERN PART OF NORTH DAKOTA NOW. A PERIOD OF RAIN OR A
RAIN/SNOW MIX IS LIKELY FROM EASTERN PORTIONS OF FOSTER SOUTH
THROUGH LAMOURE AND DICKEY BEFORE BECOMING ALL SNOW LATER. WINTER
WEATHER ADVISORY NORTHEAST IN GOOD SHAPE...AND THE WINTER WEATHER
ADVISORY WEST ALSO GOOD FOR THIS UPDATE. DID ADD GRANT COUNTY
WHICH HAS BEEN RECEIVING SNOW FOR MUCH OF THE MORNING AND MAY GET
GRAZED WITH THE WRAP AROUND SNOW TONIGHT.
DENSE FOG ADVISORY WAS EXPIRED WITH THE ISSUANCE OF THE WSW.
UPDATE
ISSUED AT 1005 AM CST MON DEC 22 2014
ANOTHER COMPLEX WEATHER SCENARIO ACROSS THE NORTHERN PLAINS THIS
MORNING.
DEFORMATION ZONE WELL ESTABLISHED ACROSS WESTERN NORTH DAKOTA
CONTRIBUTING TO ACCUMULATING SNOWFALL AS EXPECTED. REGIONAL
SATELLITE IMAGERY DEPICTS THE AXIS OF DILATATION WELL...STRETCHED
FROM WESTERN/CENTRAL SOUTH DAKOTA BACK NORTH-NORTHWEST ACROSS
WESTERN NORTH DAKOTA INTO SOUTHERN SASKATCHEWAN. CURRENT WINTER
WEATHER ADVISORY IN GOOD SHAPE THERE.
MODELS YESTERDAY ACCURATELY PREDICTED THE UNSATURATED ATMOSPHERE
NOW IN PLACE ACROSS THE NORTHEASTERN QUARTER OF THE STATE.
WIDESPREAD FREEZING DRIZZLE HAS BEEN ONGOING AND CONTINUES THERE.
MY COUNTIES BORDERING THE DEVILS LAKE BASIN ARE ON THE EDGE OF MID
LEVEL CLOUDS/SATURATE AIR ALOFT TO THE WEST. WE MADE A FEW CALLS TO
THOSE LOCATIONS AND BASED ON THOSE REPORTS AND IN COLLABORATION
WITH WFO GRAND FORKS OPTED TO HOIST A WINTER WEATHER ADVISORY FOR
THE FREEZING DRIZZLE. ENDED AT 00Z AS MODELS SUGGEST WE SHOULD BE
WELL SATURATED THROUGH THE MID LEVELS BY LATE THIS AFTERNOON.
DENSE FOG ADVISORY WAS EXTENDED THROUGH 19Z WITH VIS STILL 1/4
MILE OR LESS MANY LOCATIONS. WILL REEVALUATE OVER THE NEXT 3 HOURS
IN CASE IT NEEDS TO BE RE EXTENDED...OR PORTIONS OF IT.
NEXT WEATHER HAZARD WILL BE SNOW DEVELOPMENT ACROSS THE JAMES
RIVER VALLEY AND OVER MY FAR SOUTH CENTRAL AS A TROWAL BECOMES
ESTABLISHED AND WRAPS OVER THE EASTERN DAKOTAS. A WINTER WEATHER
ADVISORY MAY BE NEEDED THERE IN THE NEAR FUTURE AND WILL MAKE THAT
DECISION BEFORE 3PM CST TODAY.
UPDATE ISSUED AT 655 AM CST MON DEC 22 2014
WITH THIS UPDATE ISSUED A DENSE FOG ADVISORY THROUGH 16 UTC FOR
SOUTH CENTRAL NORTH DAKOTA AND THE JAMES RIVER VALLEY GIVEN
CURRENT OBSERVATIONS AND WEBCAMS. ALSO HIGHLIGHTED THE FREEZING
DRIZZLE POTENTIAL FOR THESE AREAS AS WELL. WILL ISSUE AN SPS FOR
THE NORTH CENTRAL WHERE FOG IS NOT DENSE...BUT...PATCHY FREEZING
DRIZZLE IS ALSO POSSIBLE. IN REGARDS TO THE WINTER WEATHER
ADVISORY...ADDED DIVIDE AND WILLIAMS COUNTIES AS THE 06 UTC
NAM/GFS...00 UTC GEM AND 10-11 UTC RAP RUNS ALL HIGHLIGHT THIS
AREA FOR THREE TO FOUR INCHES OF SNOW TODAY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM CST MON DEC 22 2014
FORECAST HIGHLIGHTS IN THE SHORT TERM WILL INCLUDE FOG AND THE
POSSIBILITY OF FREEZING DRIZZLE IN CENTRAL NORTH DAKOTA THIS
MORNING. THEN ATTENTION TURNS TO DEVELOPING SNOW IN THE WEST
SPREADING INTO CENTRAL NORTH DAKOTA...WITH ACCUMULATING SNOW AND
SOME BLOWING SNOW.
CURRENTLY...A SURFACE LOW WAS CENTERED OVER WESTERN NORTH DAKOTA -
OVER WESTERN LAKE SAKAKAWEA...WITH A TROUGH EXTENDING SOUTHEASTWARD
INTO CENTRAL SOUTH DAKOTA. LOW STRATUS CLOUDS BELOW 500 FEET AND FOG
WITH VISIBILITIES FROM 1/2 MILE TO 5 MILES. AT UPPER LEVELS A BROAD
TROUGH WAS IN PLACE ACROSS THE FRONT RANGE AND PLAINS STATES. WATER
VAPOR SAT LOOP INDICATES A SMALL CIRCULATION ACROSS SOUTHWESTERN
NORTH DAKOTA AND INTO WESTERN SOUTH DAKOTA...INDICATIVE OF EMBEDDED
SHORTWAVE AND A MINOR UPPER LOW. REGIONAL RADAR MOSAIC LOOPS
INDICATE INCREASING COVERAGE IN LIGHT RETURNS FROM NORTHEASTERN
MONTANA ACROSS WESTERN NORTH DAKOTA INTO CENTRAL/WESTERN SOUTH
DAKOTA. DICKINSON REPORTED "UNKNOWN PRECIPITATION" THIS PAST
HOUR...WHICH COULD BE RAIN CHANGING TO SNOW.
THE UPPER LEVEL LOW/TROUGH IS EXPECTED TO CONTINUE DEVELOPING A
CLOSED LOW OVER SOUTH DAKOTA THIS AFTERNOON. THIS WILL INDUCE THE
SURFACE LOW CENTER TO DEVELOP SOUTH INTO CENTRAL/EASTERN SOUTH
DAKOTA TODAY. THUS THE MAIN ENERGY...UPPER LEVEL CIRCULATION AND
LIFT...AND BEST SURFACE CONVERGENCE WILL DEVELOP SOUTH OF THE ND/SD
BORDER. SINCE THE EVOLUTION OF THIS SYSTEM HAS SLOWED AND EXPECTED
PRECIPITATION HAS BEEN LATER THAN PREVIOUSLY FORECAST...COMBINED
WITH THE SOUTHWARD MOVEMENT OF THE STORM SYSTEM...WE DO NOT EXPECT
QUITE AS MUCH SNOWFALL ACROSS WESTERN AND CENTRAL NORTH DAKOTA.
INSTEAD THE BULK OF THE SNOW IS EXPECTED IN SOUTH DAKOTA AND INTO
SOUTHERN MINNESOTA.
EXPECT DEVELOPING SNOW OVER WESTERN NORTH DAKOTA THIS
MORNING...SPREADING INTO CENTRAL NORTH DAKOTA LATER THIS
MORNING...AND CONTINUING MAINLY ACROSS THE SOUTHERN HALF OF NORTH
DAKOTA TONIGHT AND INTO TUESDAY.
TOTAL SNOWFALL EXPECTED TODAY THROUGH TUESDAY: NORTHERN NORTH DAKOTA
SNOWFALL TOTALS SHOULD RANGE FROM 1/2 INCH IN THE TURTLE MOUNTAINS
TO AROUND 2 INCHES AT WILLISTON. ACROSS SOUTHERN NORTH DAKOTA
SNOWFALL TOTALS OF 2 TO 2 1/2 INCHES ALONG AND SOUTH OF A LINE FROM
WATFORD CITY TO HARVEY AND CARRINGTON.
NORTHWEST WINDS OF 15 TO 30 MPH ARE EXPECTED OVER SOUTHWESTERN NORTH
DAKOTA TODAY AND TONIGHT. THIS WILL CREATE AREAS OF BLOWING AND
DRIFTING SNOW THAT WOULD IMPACT HOLIDAY TRAVEL. A WINTER WEATHER
ADVISORY HAD BEEN ISSUED FOR THIS AREA...IN EFFECT TODAY AND
TONIGHT. WILL KEEP THIS ADVISORY GOING BECAUSE OF THE BLOWING SNOW
HAZARD REDUCING VISIBILITIES...DESPITE THE LOWER SNOW AMOUNTS
EXPECTED. WILL ALSO KEEP A SPECIAL WEATHER STATEMENT RUNNING FOR THE
REST OF WESTERN AND CENTRAL NORTH DAKOTA TO HIGHLIGHT THE EXPECTED
SNOW FOR HOLIDAY TRAVEL.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 352 AM CST MON DEC 22 2014
DIMINISHING SNOW ON TUESDAY AND LIGHT SNOW CHRISTMAS DAY HIGHLIGHT
THE EXTENDED FORECAST.
TO BEGIN THE PERIOD...THE 00 UTC DETERMINISTIC AND ENSEMBLE SUITES
ARE IN AGREEMENT ON WRAP AROUND LIGHT SNOWFALL ENDING FROM WEST
TO EAST THROUGH TUESDAY ACROSS NORTH DAKOTA AS THE UPPER LEVEL LOW
SLOWLY FILLS AND PROPAGATES INTO THE GREAT LAKES. TRAVEL ON
WEDNESDAY ACROSS THE NORTHERN PLAINS LOOKS GOOD. HOWEVER...FOR
CHRISTMAS DAY THURSDAY THE MODELS BEGIN TO DIVERGE ON THEIR TIMING
AND EVOLUTION OF THE PACIFIC NORTHWEST WAVE AS IT PROPAGATES
ACROSS THE ROCKIES...WITH AN ASSOCIATED SNOW BAND IN ISENTROPIC
LIFT POSSIBLE ACROSS THE DAKOTAS. WHILE UNCERTAINTY
REMAINS...SOME TRAVEL IMPACTS ARE POSSIBLE FOR CHRISTMAS DAY
ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THEREAFTER...TEMPERATURES
TREND BELOW NORMAL A AS ABROAD LONG WAVE TROUGH ENVELOPS THE CONUS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1221 PM CST MON DEC 22 2014
HAZARDS TO AVIATION TODAY INVOLVE LOW IFR CONDITIONS WITH PATCHY
FREEZING DRIZZLE CENTRAL AND EAST TODAY...SNOW WEST...AND
DEVELOPING SNOW SOUTH CENTRAL AND SOUTHEAST TODAY INTO TONIGHT.
MVFR/IFR CONDITIONS IN SNOW AND BLOWING SNOW AT KISN-KDIK WITH
GUSTS TO 30 KTS AND VSBYS LESS THAN 1 MILE AT TIMES IN BLOWING
SNOW. MVFR/IFR IN SNOW WEST SPREADING EAST. WIDESPREAD IFR
CONDITIONS WILL PERSIST THROUGH TUESDAY MORNING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST TUESDAY FOR NDZ025-036-
037-045>048-050-051.
WINTER WEATHER ADVISORY UNTIL 6 AM CST /5 AM MST/ TUESDAY FOR
NDZ001-009-017-031>033-040>044.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NDZ005-
013-023.
&&
$$
UPDATE...NH
SHORT TERM...JV
LONG TERM...AYD
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1005 AM CST MON DEC 22 2014
.UPDATE...
ISSUED AT 1005 AM CST MON DEC 22 2014
ANOTHER COMPLEX WEATHER SCENARIO ACROSS THE NORTHERN PLAINS THIS
MORNING.
DEFORMATION ZONE WELL ESTABLISHED ACROSS WESTERN NORTH DAKOTA
CONTRIBUTING TO ACCUMULATING SNOWFALL AS EXPECTED. REGIONAL
SATELLITE IMAGERY DEPICTS THE AXIS OF DILATATION WELL...STRETCHED
FROM WESTERN/CENTRAL SOUTH DAKOTA BACK NORTH-NORTHWEST ACROSS
WESTERN NORTH DAKOTA INTO SOUTHERN SASKATCHEWAN. CURRENT WINTER
WEATHER ADVISORY IN GOOD SHAPE THERE.
MODELS YESTERDAY ACCURATELY PREDICTED THE UNSATURATED ATMOSPHERE
NOW IN PLACE ACROSS THE NORTHEASTERN QUARTER OF THE STATE.
WIDESPREAD FREEZING DRIZZLE HAS BEEN ONGOING AND CONTINUES THERE.
MY COUNTIES BORDERING THE DEVILS LAKE BASIN ARE ON THE EDGE OF MID
LEVEL CLOUDS/SATURATE AIR ALOFT TO THE WEST. WE MADE A FEW CALLS TO
THOSE LOCATIONS AND BASED ON THOSE REPORTS AND IN COLLABORATION
WITH WFO GRAND FORKS OPTED TO HOIST A WINTER WEATHER ADVISORY FOR
THE FREEZING DRIZZLE. ENDED AT 00Z AS MODELS SUGGEST WE SHOULD BE
WELL SATURATED THROUGH THE MID LEVELS BY LATE THIS AFTERNOON.
DENSE FOG ADVISORY WAS EXTENDED THROUGH 19Z WITH VIS STILL 1/4
MILE OR LESS MANY LOCATIONS. WILL REEVALUATE OVER THE NEXT 3 HOURS
IN CASE IT NEEDS TO BE RE EXTENDED...OR PORTIONS OF IT.
NEXT WEATHER HAZARD WILL BE SNOW DEVELOPMENT ACROSS THE JAMES
RIVER VALLEY AND OVER MY FAR SOUTH CENTRAL AS A TROWAL BECOMES
ESTABLISHED AND WRAPS OVER THE EASTERN DAKOTAS. A WINTER WEATHER
ADVISORY MAY BE NEEDED THERE IN THE NEAR FUTURE AND WILL MAKE THAT
DECISION BEFORE 3PM CST TODAY.
UPDATE ISSUED AT 655 AM CST MON DEC 22 2014
WITH THIS UPDATE ISSUED A DENSE FOG ADVISORY THROUGH 16 UTC FOR
SOUTH CENTRAL NORTH DAKOTA AND THE JAMES RIVER VALLEY GIVEN
CURRENT OBSERVATIONS AND WEBCAMS. ALSO HIGHLIGHTED THE FREEZING
DRIZZLE POTENTIAL FOR THESE AREAS AS WELL. WILL ISSUE AN SPS FOR
THE NORTH CENTRAL WHERE FOG IS NOT DENSE...BUT...PATCHY FREEZING
DRIZZLE IS ALSO POSSIBLE. IN REGARDS TO THE WINTER WEATHER
ADVISORY...ADDED DIVIDE AND WILLIAMS COUNTIES AS THE 06 UTC
NAM/GFS...00 UTC GEM AND 10-11 UTC RAP RUNS ALL HIGHLIGHT THIS
AREA FOR THREE TO FOUR INCHES OF SNOW TODAY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM CST MON DEC 22 2014
FORECAST HIGHLIGHTS IN THE SHORT TERM WILL INCLUDE FOG AND THE
POSSIBILITY OF FREEZING DRIZZLE IN CENTRAL NORTH DAKOTA THIS
MORNING. THEN ATTENTION TURNS TO DEVELOPING SNOW IN THE WEST
SPREADING INTO CENTRAL NORTH DAKOTA...WITH ACCUMULATING SNOW AND
SOME BLOWING SNOW.
CURRENTLY...A SURFACE LOW WAS CENTERED OVER WESTERN NORTH DAKOTA -
OVER WESTERN LAKE SAKAKAWEA...WITH A TROUGH EXTENDING SOUTHEASTWARD
INTO CENTRAL SOUTH DAKOTA. LOW STRATUS CLOUDS BELOW 500 FEET AND FOG
WITH VISIBILITIES FROM 1/2 MILE TO 5 MILES. AT UPPER LEVELS A BROAD
TROUGH WAS IN PLACE ACROSS THE FRONT RANGE AND PLAINS STATES. WATER
VAPOR SAT LOOP INDICATES A SMALL CIRCULATION ACROSS SOUTHWESTERN
NORTH DAKOTA AND INTO WESTERN SOUTH DAKOTA...INDICATIVE OF EMBEDDED
SHORTWAVE AND A MINOR UPPER LOW. REGIONAL RADAR MOSAIC LOOPS
INDICATE INCREASING COVERAGE IN LIGHT RETURNS FROM NORTHEASTERN
MONTANA ACROSS WESTERN NORTH DAKOTA INTO CENTRAL/WESTERN SOUTH
DAKOTA. DICKINSON REPORTED "UNKNOWN PRECIPITATION" THIS PAST
HOUR...WHICH COULD BE RAIN CHANGING TO SNOW.
THE UPPER LEVEL LOW/TROUGH IS EXPECTED TO CONTINUE DEVELOPING A
CLOSED LOW OVER SOUTH DAKOTA THIS AFTERNOON. THIS WILL INDUCE THE
SURFACE LOW CENTER TO DEVELOP SOUTH INTO CENTRAL/EASTERN SOUTH
DAKOTA TODAY. THUS THE MAIN ENERGY...UPPER LEVEL CIRCULATION AND
LIFT...AND BEST SURFACE CONVERGENCE WILL DEVELOP SOUTH OF THE ND/SD
BORDER. SINCE THE EVOLUTION OF THIS SYSTEM HAS SLOWED AND EXPECTED
PRECIPITATION HAS BEEN LATER THAN PREVIOUSLY FORECAST...COMBINED
WITH THE SOUTHWARD MOVEMENT OF THE STORM SYSTEM...WE DO NOT EXPECT
QUITE AS MUCH SNOWFALL ACROSS WESTERN AND CENTRAL NORTH DAKOTA.
INSTEAD THE BULK OF THE SNOW IS EXPECTED IN SOUTH DAKOTA AND INTO
SOUTHERN MINNESOTA.
EXPECT DEVELOPING SNOW OVER WESTERN NORTH DAKOTA THIS
MORNING...SPREADING INTO CENTRAL NORTH DAKOTA LATER THIS
MORNING...AND CONTINUING MAINLY ACROSS THE SOUTHERN HALF OF NORTH
DAKOTA TONIGHT AND INTO TUESDAY.
TOTAL SNOWFALL EXPECTED TODAY THROUGH TUESDAY: NORTHERN NORTH DAKOTA
SNOWFALL TOTALS SHOULD RANGE FROM 1/2 INCH IN THE TURTLE MOUNTAINS
TO AROUND 2 INCHES AT WILLISTON. ACROSS SOUTHERN NORTH DAKOTA
SNOWFALL TOTALS OF 2 TO 2 1/2 INCHES ALONG AND SOUTH OF A LINE FROM
WATFORD CITY TO HARVEY AND CARRINGTON.
NORTHWEST WINDS OF 15 TO 30 MPH ARE EXPECTED OVER SOUTHWESTERN NORTH
DAKOTA TODAY AND TONIGHT. THIS WILL CREATE AREAS OF BLOWING AND
DRIFTING SNOW THAT WOULD IMPACT HOLIDAY TRAVEL. A WINTER WEATHER
ADVISORY HAD BEEN ISSUED FOR THIS AREA...IN EFFECT TODAY AND
TONIGHT. WILL KEEP THIS ADVISORY GOING BECAUSE OF THE BLOWING SNOW
HAZARD REDUCING VISIBILITIES...DESPITE THE LOWER SNOW AMOUNTS
EXPECTED. WILL ALSO KEEP A SPECIAL WEATHER STATEMENT RUNNING FOR THE
REST OF WESTERN AND CENTRAL NORTH DAKOTA TO HIGHLIGHT THE EXPECTED
SNOW FOR HOLIDAY TRAVEL.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 352 AM CST MON DEC 22 2014
DIMINISHING SNOW ON TUESDAY AND LIGHT SNOW CHRISTMAS DAY HIGHLIGHT
THE EXTENDED FORECAST.
TO BEGIN THE PERIOD...THE 00 UTC DETERMINISTIC AND ENSEMBLE SUITES
ARE IN AGREEMENT ON WRAP AROUND LIGHT SNOWFALL ENDING FROM WEST
TO EAST THROUGH TUESDAY ACROSS NORTH DAKOTA AS THE UPPER LEVEL LOW
SLOWLY FILLS AND PROPAGATES INTO THE GREAT LAKES. TRAVEL ON
WEDNESDAY ACROSS THE NORTHERN PLAINS LOOKS GOOD. HOWEVER...FOR
CHRISTMAS DAY THURSDAY THE MODELS BEGIN TO DIVERGE ON THEIR TIMING
AND EVOLUTION OF THE PACIFIC NORTHWEST WAVE AS IT PROPAGATES
ACROSS THE ROCKIES...WITH AN ASSOCIATED SNOW BAND IN ISENTROPIC
LIFT POSSIBLE ACROSS THE DAKOTAS. WHILE UNCERTAINTY
REMAINS...SOME TRAVEL IMPACTS ARE POSSIBLE FOR CHRISTMAS DAY
ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THEREAFTER...TEMPERATURES
TREND BELOW NORMAL A AS ABROAD LONG WAVE TROUGH ENVELOPS THE CONUS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 1005 AM CST MON DEC 22 2014
HAZARDS TO AVIATION TODAY INVOLVE LOW IFR CONDITIONS WITH PATCHY
FREEZING DRIZZLE CENTRAL AND EAST THIS MORNING. MVFR/IFR CONDITIONS
IN SNOW AND BLOWING SNOW AT KISN-KDIK WITH GUSTS TO 30 KTS AND VSBYS
LESS THAN 1 MILE AT TIMES IN BLOWING SNOW. MVFR/IFR IN SNOW WEST
SPREADING EAST. WIDESPREAD IFR CONDITIONS WILL PERSIST INTO
TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 1 PM CST /NOON MST/ THIS AFTERNOON FOR
NDZ034>037-042-045>048-050-051.
WINTER WEATHER ADVISORY UNTIL 6 AM CST /5 AM MST/ TUESDAY FOR
NDZ001-009-017-031>033-040-041-043-044.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NDZ005-
013-023-025.
&&
$$
UPDATE...NH
SHORT TERM...JV
LONG TERM...AYD
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
654 AM CST MON DEC 22 2014
.UPDATE...
ISSUED AT 655 AM CST MON DEC 22 2014
WITH THIS UPDATE ISSUED A DENSE FOG ADVISORY THROUGH 16 UTC FOR
SOUTH CENTRAL NORTH DAKOTA AND THE JAMES RIVER VALLEY GIVEN
CURRENT OBSERVATIONS AND WEBCAMS. ALSO HIGHLIGHTED THE FREEZING
DRIZZLE POTENTIAL FOR THESE AREAS AS WELL. WILL ISSUE AN SPS FOR
THE NORTH CENTRAL WHERE FOG IS NOT DENSE...BUT...PATCHY FREEZING
DRIZZLE IS ALSO POSSIBLE. IN REGARDS TO THE WINTER WEATHER
ADVISORY...ADDED DIVIDE AND WILLIAMS COUNTIES AS THE 06 UTC
NAM/GFS...00 UTC GEM AND 10-11 UTC RAP RUNS ALL HIGHLIGHT THIS
AREA FOR THREE TO FOUR INCHES OF SNOW TODAY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM CST MON DEC 22 2014
FORECAST HIGHLIGHTS IN THE SHORT TERM WILL INCLUDE FOG AND THE
POSSIBILITY OF FREEZING DRIZZLE IN CENTRAL NORTH DAKOTA THIS
MORNING. THEN ATTENTION TURNS TO DEVELOPING SNOW IN THE WEST
SPREADING INTO CENTRAL NORTH DAKOTA...WITH ACCUMULATING SNOW AND
SOME BLOWING SNOW.
CURRENTLY...A SURFACE LOW WAS CENTERED OVER WESTERN NORTH DAKOTA -
OVER WESTERN LAKE SAKAKAWEA...WITH A TROUGH EXTENDING SOUTHEASTWARD
INTO CENTRAL SOUTH DAKOTA. LOW STRATUS CLOUDS BELOW 500 FEET AND FOG
WITH VISIBILITIES FROM 1/2 MILE TO 5 MILES. AT UPPER LEVELS A BROAD
TROUGH WAS IN PLACE ACROSS THE FRONT RANGE AND PLAINS STATES. WATER
VAPOR SAT LOOP INDICATES A SMALL CIRCULATION ACROSS SOUTHWESTERN
NORTH DAKOTA AND INTO WESTERN SOUTH DAKOTA...INDICATIVE OF EMBEDDED
SHORTWAVE AND A MINOR UPPER LOW. REGIONAL RADAR MOSAIC LOOPS
INDICATE INCREASING COVERAGE IN LIGHT RETURNS FROM NORTHEASTERN
MONTANA ACROSS WESTERN NORTH DAKOTA INTO CENTRAL/WESTERN SOUTH
DAKOTA. DICKINSON REPORTED "UNKNOWN PRECIPITATION" THIS PAST
HOUR...WHICH COULD BE RAIN CHANGING TO SNOW.
THE UPPER LEVEL LOW/TROUGH IS EXPECTED TO CONTINUE DEVELOPING A
CLOSED LOW OVER SOUTH DAKOTA THIS AFTERNOON. THIS WILL INDUCE THE
SURFACE LOW CENTER TO DEVELOP SOUTH INTO CENTRAL/EASTERN SOUTH
DAKOTA TODAY. THUS THE MAIN ENERGY...UPPER LEVEL CIRCULATION AND
LIFT...AND BEST SURFACE CONVERGENCE WILL DEVELOP SOUTH OF THE ND/SD
BORDER. SINCE THE EVOLUTION OF THIS SYSTEM HAS SLOWED AND EXPECTED
PRECIPITATION HAS BEEN LATER THAN PREVIOUSLY FORECAST...COMBINED
WITH THE SOUTHWARD MOVEMENT OF THE STORM SYSTEM...WE DO NOT EXPECT
QUITE AS MUCH SNOWFALL ACROSS WESTERN AND CENTRAL NORTH DAKOTA.
INSTEAD THE BULK OF THE SNOW IS EXPECTED IN SOUTH DAKOTA AND INTO
SOUTHERN MINNESOTA.
EXPECT DEVELOPING SNOW OVER WESTERN NORTH DAKOTA THIS
MORNING...SPREADING INTO CENTRAL NORTH DAKOTA LATER THIS
MORNING...AND CONTINUING MAINLY ACROSS THE SOUTHERN HALF OF NORTH
DAKOTA TONIGHT AND INTO TUESDAY.
TOTAL SNOWFALL EXPECTED TODAY THROUGH TUESDAY: NORTHERN NORTH DAKOTA
SNOWFALL TOTALS SHOULD RANGE FROM 1/2 INCH IN THE TURTLE MOUNTAINS
TO AROUND 2 INCHES AT WILLISTON. ACROSS SOUTHERN NORTH DAKOTA
SNOWFALL TOTALS OF 2 TO 2 1/2 INCHES ALONG AND SOUTH OF A LINE FROM
WATFORD CITY TO HARVEY AND CARRINGTON.
NORTHWEST WINDS OF 15 TO 30 MPH ARE EXPECTED OVER SOUTHWESTERN NORTH
DAKOTA TODAY AND TONIGHT. THIS WILL CREATE AREAS OF BLOWING AND
DRIFTING SNOW THAT WOULD IMPACT HOLIDAY TRAVEL. A WINTER WEATHER
ADVISORY HAD BEEN ISSUED FOR THIS AREA...IN EFFECT TODAY AND
TONIGHT. WILL KEEP THIS ADVISORY GOING BECAUSE OF THE BLOWING SNOW
HAZARD REDUCING VISIBILITIES...DESPITE THE LOWER SNOW AMOUNTS
EXPECTED. WILL ALSO KEEP A SPECIAL WEATHER STATEMENT RUNNING FOR THE
REST OF WESTERN AND CENTRAL NORTH DAKOTA TO HIGHLIGHT THE EXPECTED
SNOW FOR HOLIDAY TRAVEL.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 352 AM CST MON DEC 22 2014
DIMINISHING SNOW ON TUESDAY AND LIGHT SNOW CHRISTMAS DAY HIGHLIGHT
THE EXTENDED FORECAST.
TO BEGIN THE PERIOD...THE 00 UTC DETERMINISTIC AND ENSEMBLE SUITES
ARE IN AGREEMENT ON WRAP AROUND LIGHT SNOWFALL ENDING FROM WEST
TO EAST THROUGH TUESDAY ACROSS NORTH DAKOTA AS THE UPPER LEVEL LOW
SLOWLY FILLS AND PROPAGATES INTO THE GREAT LAKES. TRAVEL ON
WEDNESDAY ACROSS THE NORTHERN PLAINS LOOKS GOOD. HOWEVER...FOR
CHRISTMAS DAY THURSDAY THE MODELS BEGIN TO DIVERGE ON THEIR TIMING
AND EVOLUTION OF THE PACIFIC NORTHWEST WAVE AS IT PROPAGATES
ACROSS THE ROCKIES...WITH AN ASSOCIATED SNOW BAND IN ISENTROPIC
LIFT POSSIBLE ACROSS THE DAKOTAS. WHILE UNCERTAINTY
REMAINS...SOME TRAVEL IMPACTS ARE POSSIBLE FOR CHRISTMAS DAY
ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THEREAFTER...TEMPERATURES
TREND BELOW NORMAL A AS ABROAD LONG WAVE TROUGH ENVELOPS THE CONUS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 654 AM CST MON DEC 22 2014
HAZARDS TO AVIATION TODAY INVOLVE LOW IFR CONDITIONS WITH PATCHY
FREEZING DRIZZLE CENTRAL AND EAST THIS MORNING. MVFR/IFR CONDITIONS
IN SNOW AND BLOWING SNOW AT KDIK WITH GUSTS TO 35 KTS AND VSBYS LESS
THAN 1 MILE AT TIMES IN BLOWING SNOW. MVFR/IFR IN SNOW WEST
SPREADING EAST. WIDESPREAD IFR CONDITIONS WILL PERSIST INTO
TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CST /9 AM MST/ THIS MORNING FOR
NDZ034>037-042-045>048-050-051.
WINTER WEATHER ADVISORY UNTIL 6 AM CST /5 AM MST/ TUESDAY FOR
NDZ001-009-017-031>033-040-041-043-044.
&&
$$
UPDATE...AYD
SHORT TERM...JV
LONG TERM...AYD
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1246 AM CST MON DEC 22 2014
.UPDATE...
ISSUED AT 1246 AM CST MON DEC 22 2014
SURFACE LOW WAS OVER WILLISTON/WATFORD CITY AREA WITH A TROUGH
EXTENDING SOUTHEAST INTO CENTRAL SOUTH DAKOTA. SOUTHEAST WINDS AHEAD
OF THE TROUGH HAD PULLED STRATUS AND FOG WESTWARD DURING THE
EVENING. WEST OF THE TROUGH WINDS HAD BECOME NORTHWESTERLY AND
EXPECT COLD AIR TO BEGIN FILTERING IN GRADUALLY BEHIND THIS SYSTEM.
TEMPERATURES WERE IN THE 20S OVER SOUTHERN SASKATCHEWAN...WITH MID
30S IN NORTHEASTERN MONTANA. TEMPERATURES STILL IN THE MID AND UPPER
30S OVER SOUTHWESTERN NORTH DAKOTA.
PRECIPITATION COVERAGE IS SPARSE AT THIS TIME...BUT REPORTS EARLIER
THIS EVENING INDICATED PRECIPITATION TYPE AS RAIN. GLASGOW MONTANA
BEGAN REPORTING LIGHT SNOW AT 05Z OR 11 PM CST. THUS THE ONSET OF
LIGHT SNOW IS LATER THAN PREVIOUSLY FORECAST. HAVE ADJUSTED THIS
TIMING...SUCH THAT BY 3-4AM CST OR 2-3 AM MST LIGHT SNOW COULD BE
FALLING IN THE FAR SOUTHWEST...AROUND BEACH OR BOWMAN/HETTINGER.
REGARDING THE SPARSE COVERAGE...LATEST DOPPLER RADAR LOOPS INDICATED
THAT LIGHT RADAR RETURNS WERE BEGINNING TO INCREASE OVER
NORTHEASTERN MONTANA...ALONG THE MISSOURI RIVER IN NORTH
DAKOTA...AND LIGHT RETURNS SEEN ON THE BOWMAN RADAR FROM BAKER MT TO
HETTINGER. THINKING THAT WITH TIME THIS MORNING THERE WILL BE MORE
INSTABILITY ACROSS THIS REGION AS THE ENERGY FROM THE UPPER LEVEL
SHORTWAVE CONTINUES MOVING INTO WESTERN NORTH DAKOTA.
THUS PRECIPITATION THAT FALLS SHOULD BE RAIN SOUTHWEST...CHANGING TO
LIGHT SNOW. NORTHWEST SHOULD SEE A MIX OF LIGHT SNOW OR FREEZING
RAIN BEFORE CHANGING QUICKLY OVER TO SNOW. FARTHER EAST IN CENTRAL
NORTH DAKOTA AREAS OF FOG WILL PERSIST...THEN THE FREEZING RAIN
THREAT WILL LINGER UNTIL AROUND 4-5 AM CST WHEN PRECIPITATION SHOULD
BE ALL SNOW.
UPDATE ISSUED AT 928 PM CST SUN DEC 21 2014
WIDESPREAD FOG WITH VISIBILITIES BETWEEN ONE HALF AND 2 MILES COVER
CENTRAL AND EASTERN NORTH DAKOTA. ONLY MINOT AFB SHOWING SOME
FREEZING DRIZZLE AT 9 PM CST. WILL DELAY THE FREEZING DRIZZLE
SOUTH CENTRAL AND EAST CENTRAL FOR THE EVENING INTO THE OVERNIGHT
HOURS BUT EVENTUALLY SOME SHOULD SHOW UP. WILL KEEP MENTION OF
FREEZING DRIZZLE NORTH CENTRAL WHERE AT LEAST MINOT AFB IS SHOWING
SOME. STILL RAINING SOUTHWEST WITH TEMPERATURES ACROSS THE AREA
STILL IN THE MID/UPPER 30S. STILL WAITING FOR COOLER AIR TO ARRIVE
FOR THE CHANGEOVER TO SNOW WEST WHICH SHOULD HAPPEN AFTER
MIDNIGHT.
UPDATE ISSUED AT 637 PM CST SUN DEC 21 2014
COMPLEX WINTER WEATHER PATTERN BEGINNING AS RAIN ACROSS THE WEST
THIS EVENING.LOW STRATUS AND FOG CONTINUE ACROSS THE CENTRAL AND
EAST. THE POTENTIAL FOR FREEZING DRIZZLE REMAINS THERE. BASED ON
CURRENT TRENDS THE FORECAST IS OK SO FAR. WINTER WEATHER ADVISORY
BEGINS AT 06Z/11PM MST SOUTHWEST THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 312 PM CST SUN DEC 21 2014
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE
PLENTIFUL...RAIN CHANGING TO SNOW WEST THIS EVENING WITH
ACCUMULATIONS AND INCREASING WIND INTO MONDAY...AREAS OF FOG AND
PATCHY FREEZING DRIZZLE EAST...AND MORE ACCUMULATING SNOW
SOUTHEAST DEVELOPING MONDAY MORNING AND AFTERNOON.
CURRENTLY...INCOMING STORM SYSTEM ON THE NOSE OF A POWERFUL 150KT
+ UPPER LEVEL JET STREAK NOW OVER THE NORTHERN ROCKIES. ASSOCIATED
SURFACE LOW DEVELOPING AND MOVING SOUTHEAST FROM SOUTHERN ALBERTA
INTO EASTERN MONTANA. CURRENT PRECIPITATION ORIENTATED ALONG THE
SURFACE LOW`S WARM FRONT...FROM NORTH OF GLASGOW MT SOUTHEAST
INTO FAR SOUTHWESTERN NORTH DAKOTA. AREA OF LOW STRATUS AND FOG
ACROSS THE JAMES RIVER VALLEY CONTINUES TO SPREAD SLOWLY NORTH AND
WEST THANKS TO A MOIST SOUTHEASTERLY LOW LEVEL FLOW AHEAD OF THE
SFC LOW.
COMPLEX FORECAST OVER THE NEXT 24-36 HOURS. AS THE
HRRR...NAM...AND RAP ALL INDICATE...STRATUS AND FOG NOW OVER THE
JAMES VALLEY WILL CONTINUE TO EXPAND WEST AND NORTH ACROSS THE
JAMES RIVER VALLEY INTO CENTRAL NORTH DAKOTA TONIGHT. WILL NEED
TO MONITOR VISIBILITIES IN CASE A DENSE FOG ADVISORY IS NEEDED FOR
THE JAMES VALLEY OR OTHER AREAS THIS EVENING. ALSO...MODELS
HINTING RATHER STRONGLY AT LIGHT PRECIPITATION OVER MY EAST. WITH
DRY AIR ALOFT OPTED TO MAINTAIN A MENTION OF FREEZING DRIZZLE WITH
THE STRATUS AND FOG UNTIL WE BECOME SATURATED OVERNIGHT.
POPS ON TRACK WITH INCREASING CHANCES FOR PRECIPITATION IN THE
FORM OF RAIN SOUTHWEST AND A MIX NORTHWEST THIS AFTERNOON AND
EVENING...EVENTUALLY CHANGING TO ALL SNOW BY LATE EVENING. SNOW
CONTINUES ACROSS THE WEST AND EVEN REDEVELOPS ON MONDAY AS A
DEFORMATION ZONE AND ANOTHER MID LEVEL IMPULSE IMPACT THE AREA.
WITH CAA SNOW RATIOS WILL SUPPORT ACCUMULATING SNOWFALL OF 1 TO
NEAR 4 INCHES ACROSS THE SOUTHWEST. COMBINED WITH 15-25KTS OF WIND
ON THE BACKSIDE OF THE SFC LOW...OPTED TO HOIST A WINTER WEATHER
ADVISORY STARTING 06Z TONIGHT THROUGH 12Z TUESDAY.
ACROSS THE SOUTHEAST ON MONDAY...THE STORM SYSTEM PUSHING
SOUTHEAST TONIGHT WILL BE OVER WESTERN IOWA MONDAY...WRAPPING A
TROWAL BACK NORTHWEST AND THEN SOUTHWARD THROUGH THE EASTERN
DAKOTAS...INCLUDING THE JAMES RIVER VALLEY. TWO TO FOUR INCHES
WILL BE POSSIBLE THERE. WILL CONTINUE WITH THE SPS FOR THIS AREA
FOR NOW AND LET THE MID CREW DIGEST NEWER MODEL DATA. STILL SOME
UNCERTAINTY WITH QPF AND PLACEMENTS WITH MODELS NOT 100 PERCENT IN
AGREEMENT JUST YET.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 312 PM CST SUN DEC 21 2014
WINTER WEATHER MONDAY INTO TUESDAY...IMPACTING EARLY CHRISTMAS
TRAVEL FOR MUCH OF NORTH DAKOTA.
THE CURRENT MODEL SUITE PROVIDES GOOD AGREEMENT ON A STRONG LOW
PRESSURE SYSTEM BOTTOMING OUT OVER THE CENTRAL NORTHERN
PLAINS...KEEPING MUCH OF THE PRECIPITATION TO THE SOUTH AND EAST OF
NORTH DAKOTA. GOOD MODEL CONSENSUS ON TRACKING... THE SYSTEM IS
PROJECTED TO SLIDE SOUTH OVER NEBRASKA...THEN BEGIN TO TRACK
NORTHEASTWARD BY MONDAY NIGHT. AS THE SYSTEM TRACKS
NORTHEAST...BETWEEN TWO AND THREE INCHES OF SNOW IS FORECAST FOR
EASTERN AND SOUTHERN PORTIONS OF NORTH DAKOTA. OTHER AREAS COULD
RECEIVE UP TO AN INCH. BREEZY NORTHWESTERLY WINDS ARE ALSO FORECAST
ACROSS MUCH OF THE STATE...CREATING THE POTENTIAL FOR REDUCED
VISIBILITIES AND HAZARDOUS TRAVEL CONDITIONS.
SEASONAL TEMPERATURES ARE EXPECTED THROUGH MUCH OF THE EXTENDED.
THOUGH...ARCTIC LOW PRESSURE IS PROJECTED TO BEGIN SAGGING SOUTHWARD
FRIDAY...PRODUCING BELOW AVERAGE TEMPERATURES FRIDAY INTO SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1246 AM CST MON DEC 22 2014
HAZARDS TO AVIATION TONIGHT INVOLVE LOW IFR CONDITIONS WITH
FREEZING DRIZZLE CENTRAL AND EAST AND RAIN CHANGING TO SNOW WITH A
WINTRY MIX OF FREEZING RAIN AND SLEET WEST. WIDESPREAD IFR
CONDITIONS WILL PREVAIL STATEWIDE. SNOW AND BLOWING SNOW SOUTHWEST
WILL IMPACT KDIK WITH GUSTS TO 35 KTS AND VSBYS 1 MILE IN SNOW AND
BLOWING SNOW MONDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM CST /5 AM MST/ TUESDAY FOR
NDZ017-031>033-040-041-043-044.
&&
$$
UPDATE...JV
SHORT TERM...NH
LONG TERM...AC
AVIATION...JV
FORECAST DISCUSSION.
A WEAK LEAD SHORTWAVE IS FORECAST TO ROTATE NORTHEAST THROUGH THE
OHIO VALLEY ON MONDAY MORNING...COMBINING WITH THE FRONT EDGE OF
THE NORTHWARD-MOVING MOISTURE. THERE APPEARS TO BE JUST ENOUGH
ISENTROPIC LIFT TO SUPPORT SOME WEAK SHOWERS...MAINLY IN THE
SOUTHERN AND SOUTHEASTERN PORTIONS OF THE FORECAST AREA...WHERE A
20-POP HAS BEEN USED IN THE FORECAST. HOWEVER...THIS SHORTWAVE
WILL BE WEAKENING WITH TIME...AND WIDESPREAD PRECIPITATION IS NOT
LIKELY TO OCCUR. AS THIS LIGHT PRECIPITATION MOVES IN...THE REGION
WILL BE COMING OUT OF ANOTHER CHILLY MORNING...WITH TEMPERATURES
ONLY EXPECTED TO RISE ABOVE FREEZING JUST BEFORE THE PRECIPITATION
ARRIVES. A WORST-CASE SCENARIO COULD SUPPORT SOME LIGHT FZRA NEAR
THE OHIO RIVER AT AROUND 12Z...BUT IT APPEARS THAT THE
PRECIPITATION WILL BE LIGHT/SPARSE ENOUGH (AND TEMPERATURES
WARMING JUST SOON ENOUGH) TO MAKE THIS A LOW-PROBABILITY SCENARIO.
TEMPERATURES ON MONDAY WILL WARM SIGNIFICANTLY BEYOND VALUES ON
SUNDAY...THANKS TO WARM ADVECTION...AND EVEN IN THE ABSENCE OF
MUCH INSOLATION. TEMPERATURES ACROSS THE ILN FORECAST AREA SHOULD
RANGE FROM THE LOWER-TO- MID 40S IN THE NORTH TO THE LOWER 50S IN
THE SOUTH. THESE WARMING TEMPERATURES WILL BE AIDED BY A LACK OF
PRECIPITATION...AS THE FORWARD PROGRESSION OF THE DEVELOPING LOW
PRESSURE IS NOT PARTICULARLY FAST.
CHANCES FOR PRECIPITATION WILL INCREASE AHEAD OF THE PROGRESSION
OF THE MID-LEVEL LOW...WHICH WILL BE MOVING NORTHEAST INTO THE
GREAT LAKES ON TUESDAY MORNING. AS MOISTURE CONVERGENCE INCREASES
OVER THE LOWER OHIO VALLEY...A SWATH OF SHOWERY PRECIPITATION IS
EXPECTED TO TRANSLATE NORTHEASTWARD AS WELL. THIS ACTIVITY WILL
EVENTUALLY OUTRUN THE SLOWING COLD FRONT...BUT WILL BE AIDED BY
FAVORABLE DIFFLUENT FLOW AHEAD OF THE APPROACHING UPPER JET
STREAK. WHILE THE GREATEST CHANCES FOR PRECIPITATION (AND GREATEST
MODEL OUTPUT QPF) APPEAR TO BE IN THE NORTHWESTERN CWA...THE FOCUS
FOR ANY POTENTIAL FOR THUNDER WILL BE IN THE NORTHERN KENTUCKY AND
SOUTH CENTRAL OHIO. SURFACE-BASED INSTABILITY WILL BE VERY
UNLIKELY...WITH SOME LEVEL OF INVERSION STILL REMAINING IN
PLACE...AS ALSO EVIDENCED BY THE SLIGHTLY DECOUPLED WIND
DIRECTIONS BETWEEN THE SURFACE AND 850MB. HOWEVER...850MB PARCELS
WILL HAVE A ROUGHLY MOIST-ADIABATIC PROFILE ABOVE THEM...WITH 15Z
SPC SREF PARAMETERS INDICATING AT LEAST A CHANCE OF EQUILIBRIUM
LEVELS COLD ENOUGH TO SUPPORT SOME WEAK CONVECTION. THUS...A BRIEF
PERIOD WITH A SLIGHT CHANCE OF THUNDER WAS INCLUDED THURSDAY
MORNING AND AFTERNOON IN THE SOUTHERN/SOUTHEASTERN PORTIONS OF THE
FORECAST AREA.
POPS WILL DECREASE ON TUESDAY EVENING AS THE MID-LEVEL WAVE MOVES
OFF...AND UPPER SUPPORT IS LOST. CHANCES WILL INCREASE AGAIN EARLY
WEDNESDAY MORNING...AS LOW-LEVEL FORCING AND CONVERGENCE BEGINS
TO INCREASE AHEAD OF A DEVELOPING SURFACE LOW. THROUGHOUT THIS
PERIOD...TEMPERATURES WILL BE DOMINATED BY ADVECTION...WITH
NON-DIURNAL CURVES REQUIRED FOR THE FORECAST GRIDS. HIGHS ON
TUESDAY SHOULD RANGE FROM THE LOWER 50S TO UPPER 50S FROM NORTH TO
SOUTH...WITH LITTLE CHANGE IN TEMPERATURE EXPECTED TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
LOW PRESSURE WILL DEEPEN ALONG A COLD FRONT AT THE BEGINNING OF THE
LONG TERM PERIOD. GFS/CMC ARE SIMILAR IN THE INTENSIFYING PROCESS AS
THE LOW MOVES NORTHEAST FROM THE MIDDLE OHIO VALLEY TO SOUTHEAST
ONTARIO INTO WEDNESDAY NIGHT. THE ECMWF IS A LITTLE STRONGER AND THE
NAM IS A WEAK OUTLIER. HAVE TAKEN A BLEND OF THE GFS/CMC. AS THE
DEEPENING PROCESS OCCURS...WIDESPREAD SHOWERS ARE EXPECTED WEDNESDAY
MORNING. BY WEDNESDAY AFTERNOON...THE COLD FRONT WILL PUSH NORTHEAST
THROUGH THE REGION. THE COVERAGE OF PCPN WILL DECREASE BEHIND
FRONTAL PASSAGE AS DRIER SLOT OF AIR ALOFT MOVES IN BRIEFLY. BY
WEDNESDAY NIGHT...SOME WRAP AROUND MOISTURE WILL OCCUR...BUT
COVERAGE LOOKS TO BE CHANCE AT BEST. IT WILL BE WARM AHEAD OF THE
FRONT WITH TEMPERATURES DROPPING WEDNESDAY AFTERNOON INTO THE NIGHT.
HIGHS ON WEDNESDAY WILL RANGE FROM THE 50S TO NEAR 60 WITH LOWS
BOTTOMING OUT INTO THE LOWER AND MID 30S BY CHRISTMAS MORNING. IT
SHOULD BECOME COLD ENOUGH FOR A CHANCE OF RAIN/SNOW SHOWERS AND THEN
A CHANCE OF SNOW SHOWERS CHRISTMAS EVE NIGHT. HOWEVER...LITTLE IS
EXPECTED IN THE WAY OF ACCUMULATIONS GIVEN RECENT WARM TEMPERATURES
AND NO REAL FOCUS/FORCING FOR APPRECIABLE SNOWFALL RATES. IT WILL
BECOME BRISK TO LOCALLY WINDY DURING THE PERIOD...BUT WINDS ARE
EXPECTED TO STAY BELOW ADVISORY CRITERIA ATTM.
ON CHRISTMAS DAY...DEEPENING LOW PRESSURE WILL CONTINUE TO MOVE
NORTHEAST AWAY FROM THE REGION. ANY THREAT FOR SNOW SHOWERS WILL
QUICKLY COME TO AN END DURING CHRISTMAS MORNING. BY
AFTERNOON...SKIES SHOULD BECOME PARTLY CLOUDY AS SURFACE RIDGING
QUICKLY BUILDS INTO THE AREA BEHIND DEPARTING SYSTEM. HIGHS ON
CHRISTMAS WILL RANGE FROM THE UPPER 30S TO THE LOWER 40S...NEAR
SEASONAL NORMALS.
FOR THURSDAY NIGHT...SURFACE RIDGE WILL MOVE EAST WITH RETURN
SOUTHWEST FLOW ENSUING ALONG WITH INCREASING CLOUDS AHEAD OF THE
NEXT SYSTEM.
FOR FRIDAY INTO SATURDAY...LOW PRESSURE AND A COLD FRONT WILL MOVE
ACROSS THE GREAT LAKES AND OHIO VALLEY. SYSTEM APPEARS TO BE
MOISTURE STARVED SO WILL CONTINUE WITH LOW CHANCE POPS. WE SHOULD
SEE A WARM UP ON FRIDAY FOLLOWED BY A COOL DOWN SATURDAY IN THE WAKE
OF THE SYSTEM.
BY SUNDAY...HIGH PRESSURE AND MUCH COLDER TEMPERATURES ARE EXPECTED.
HIGHS BY THEN WILL RANGE FROM THE UPPER 20S TO THE LOWER 30S.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
HIGH CLOUDS WILL MOVE ACROSS THE AREA OVERNIGHT. ADDITIONAL CLOUDS
WILL WORK INTO THE REGION LATER IN THE OVERNIGHT HOURS TO AROUND
SUNRISE. BEFORE THESE ADDITIONAL CLOUDS ARRIVE SOME AREAS MAY SEE
SOME MVFR FOG AT TIMES. SOME OF THE AREA TAF SITES HAVE BEEN GOING
BACK AND FORTH BETWEEN VFR AND MVFR ALREADY AND EXPECT THIS TO
CONTINUE THE NEXT FEW HOURS. DID KEEP KCVG AND KCMH VFR OVERNIGHT.
A FEW SHOWERS WILL BE POSSIBLE AT KCVG AND KLUK AROUND SUNRISE.
EXPECT THIS SHOWER ACTIVITY TO BE ISOLATED AND LIGHT AND DUE TO
THIS HAVE LIMITED MENTION TO VCSH. THERE IS SOME QUESTION AS TO
WHETHER TEMPERATURES WILL BE ABOVE FREEZING BY THE TIME THE LIGHT
SHOWER ACTIVITY MOVES INTO THE AREA. IF THERE IS ANY FREEZING RAIN
EXPECT IT TO BE SHORT LIVED. DRY CONDITIONS CAN THEN BE EXPECTED
FOR MOST OF THE DAYTIME HOURS. ADDITIONAL PRECIPITATION WILL BEGIN
TO MOVE INTO THE TAF SITES MONDAY NIGHT.
OUTLOOK...MVFR TO IFR CIGS AND VSBYS ARE POSSIBLE MONDAY NIGHT
INTO THURSDAY. WINDS WILL PICK UP SIGNIFICANTLY STARTING
WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...BINAU
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...NOVAK
AREA FORECAST DISCUSSION
NWS NORMAN OK
1041 PM CST SUN DEC 21 2014
.DISCUSSION...
AVIATION DISCUSSION FOR THE 06Z TAFS IS BELOW.
&&
.AVIATION...
CONFIDENCE REMAINS LOW THROUGH 18Z...THEN IS HIGH AFTERWARDS.
THE BIGGEST CHANGES TO THE PREVIOUS TAFS WERE TO DECREASE THE
DURATION OF IFR CONDITIONS NEAR KLAW...KCSM...AND KHBR. MAINLY
IFR CONDITIONS WILL CONTINUE EAST OF KGAG-KCSM-KLAW UNTIL A
SURFACE TROUGH MOVES THROUGH THE AREA. DOUBT CONDITIONS WILL
WORSEN TO AIRPORT MINIMUMS EXCEPT KGAG.
-DZ MAY CONTINUE NEAR KPNC THROUGH 18Z. A FEW -SHRA MAY MOVE
ACROSS OKLAHOMA 08-18Z...BUT DID NOT MENTION IN TAFS AS COVERAGE
SHOULD BE TOO SPARSE TO DIRECTLY AFFECT ANY GIVEN SITE.
A SURFACE TROUGH WILL BRING GUSTY NORTHWEST WINDS AND IMPROVING
CONDITIONS. THIS TROUGH WILL REACH NORTHWESTERN OKLAHOMA AROUND
10Z...KSPS AND KLAW 11-13Z...KOKC AROUND 15Z...AND KPNC AROUND
17Z. ALL SITES ARE EXPECTED TO BECOME VFR BY 18Z. WINDS WILL
DIMINISH AROUND 23Z.
MBS
&&
.PREV DISCUSSION... /ISSUED 949 PM CST SUN DEC 21 2014/
UPDATE...
THE AREAS OF DRIZZLE TODAY HAVE SHIFTED OUT OF THE FORECAST AREA
AS NO OBSERVATIONS SITES ARE REPORTING DRIZZLE ANY MORE. MAY SEE
SOME REDEVELOPMENT OF DRIZZLE LATER SINCE NAM SHOWS SOME RISING
MOTION AT THE TOP OF THE MOIST LAYER OVERNIGHT... BUT SIGNAL IS
NOT AS STRONG AS IN PREVIOUS DAYS. SIGNAL IS ALSO NOT AS STRONG AS
FOR FOG REDUCING VISIBILITIES TOO MUCH IN MOST AREAS... ALTHOUGH
THE RAP AND HRRR SHOW AN AREA OF FOG TRANSLATING SOUTHEAST ACROSS
WEST CENTRAL AND SOUTHWEST OKLAHOMA EARLY MONDAY MORNING JUST
BEHIND A WIND SHIFT MOVING ACROSS THAT AREA. HAVE EXPANDED THE
AREA THAT MENTIONS FOG TO INCLUDE THIS REGION... BUT OTHERWISE
HAVE CHANGED THE DESCRIPTOR FOR THE FOG/DRIZZLE FROM AREAS TO
PATCHY SINCE THE COVERAGE IS NOT EXPECTED TOO WIDESPREAD.
PREV DISCUSSION... /ISSUED 256 PM CST SUN DEC 21 2014/
DISCUSSION...
DRIZZLE HAS DEVELOPED THE PAST HOUR OR SO ACROSS CENTRAL PORTIONS
OF OKLAHOMA AND WILL LIKELY CONTINUE WELL INTO THE EVENING BEFORE
SHIFTING TO THE NORTH AND EAST OF CWA. COLD FRONT EXPECTED TO
ENTER NORTHWEST OKLAHOMA LATE TONIGHT AND PROGRESS QUICKLY OVER
THE REGION TOMORROW MORNING. THIS WILL HELP SCOUR OUT THE
PERSISTENT LOW CLOUDS AND FOG...BUT WE WILL HAVE TO DEAL WITH FAIR
AMOUNT OF MID AND HIGH LEVEL CLOUD COVER THROUGH TUESDAY. AS FAR
AS PRECIPITATION ASSOCIATED WITH THE FRONT AND LARGE UPPER TROUGH
THAT WILL SKIRT THE REGION...MOST OF ANY PRECIP WILL BE OVER
NORTHERN TEXAS AND FAR SOUTHERN OKLAHOMA LATE MONDAY INTO EARLY
TUESDAY AS STRONG JET ROUNDS BASE OF TROUGH AND INTERACTS WITH
ELEVATED FRONTAL SURFACE. COLD CORE SIGNAL BEING PROGD TO AFFECT
FAR NORTHWEST OKLAHOMA TUESDAY IN THE FORM OF VERY LIGHT SHOWERS
POSSIBLY MIXED WITH OR CHANGING TO LIGHT SNOW. WE WILL MENTION A
CHANCE OF SPRINKLES OR FLURRIES. WRF MOST AGGRESSIVE WITH THIS
ACTIVITY...AND VERY LIKELY OVERDONE. ECM KEEPS PRECIP UP IN
KANSAS WITH THE GFS IN BETWEEN.
OTHER THAN THE SMALL AREAS OF LIGHT PRECIP...WINDS AND TEMPS WILL
BE THE MAIN SENSIBLE IMPACTS NEXT SEVERAL DAYS...ALONG WITH A
MAJORITY OF THE REGION GETTING TO SEE THE SUN. BREEZY TOMORROW
MAINLY NORTHERN OKLAHOMA BEHIND THE FRONT. COOL WITH STRONG
NORTHWEST WINDS EXPECTED AGAIN TUESDAY...FOLLOWED BY WARMER WITH
GUSTY SOUTHWEST WINDS CHRISTMAS DAY. BACK TO COOLER AND GUSTY
NORTH WINDS FRIDAY. CHANCES FOR APPRECIABLE SUNSHINE WILL INCREASE
WEDNESDAY INTO NEXT WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 42 57 36 45 / 10 10 10 10
HOBART OK 38 58 35 46 / 10 0 10 10
WICHITA FALLS TX 42 62 39 50 / 10 0 20 10
GAGE OK 35 54 31 41 / 10 0 10 10
PONCA CITY OK 42 54 33 44 / 20 10 10 10
DURANT OK 45 60 41 51 / 10 10 20 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
26/17/17
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1046 PM EST TUE DEC 23 2014
.SYNOPSIS...
AN INTENSIFYING STORM SYSTEM WILL MOVE NORTHWARD FROM THE WESTERN
GULF COAST TO THE CENTRAL GREAT LAKES BY WEDNESDAY EVENING. THE
ASSOCIATED COLD FRONT WILL PUSH THROUGH CENTRAL PENNSYLVANIA
WEDNESDAY NIGHT. ANOTHER LESS POTENT COLD FRONT WILL MOVE ACROSS
THE AREA THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
DEEP SOUTHERLY FLOW IN ADVANCE OF TROUGH OVR THE PLAINS HAS DRAWN
A PLUME OF GULF OF MEX MOISTURE OVER THE EASTERN CONUS.
SATL-DERIVED PWAT IMAGERY AS OF THIS EVENING IS SHOWING ANOMALOUS
DEEP LYR MOISTURE VALUES ACROSS THE ENTIRE E COAST. FOR THIS
EVENING...WEAK FORCING IN THE FORM OF OROGRAPHIC LIFT WILL PRODUCE
NO MORE THAN DRIZZLE OVR MOST OF CENTRAL PA. HOWEVER...REGIONAL
RADAR LOOP AT 03Z SHOWS A LARGE AREA OF RAIN LIFTING NORTH TOWARD
PA IN ASSOC WITH LL JET AHEAD OF DEVELOPING SFC LOW ON THE GULF
COAST. AS LL JET FEATURE LIFTS NORTH...EXPECT A STEADY RAIN TO
OVERSPREAD THE REGION FROM THE SOUTH OVERNIGHT.
RADAR TRENDS AND LATEST HRRR OUTPUT SUGGEST THE STEADY RAIN WILL
REACH THE S TIER COUNTIES ARND MIDNIGHT AND THE N TIER BY ARND 09Z.
A CALM WIND HAS PROMOTED WIDESPREAD FOG THIS EVENING. HOWEVER...AS
A SERLY BREEZE DEVELOPS LATE TONIGHT...EXPECT THE FOCUS OF THE FOG
TO BE ON THE RIDGES...WITH IMPROVING VSBYS ACROSS THE SUSQ VALLEY.
TEMPS EXPECTED TO REMAIN NEARLY STEADY OVERNIGHT...AVERAGING IN
THE L40S MOST PLACES.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
A RIBBON OF HIGHER DEEP LAYER MOISTURE WILL LIKELY BRING SOAKING
RAINFALL TO CENTRAL PA EARLY IN THE DAY. BY AFTN...MDL DATA
INDICATES THE RAIN SHOULD TAPER OFF AS DRY SLOT WORKS IN FROM
THE SW. LATEST GUIDANCE CONTINUES TO TARGET THE LOWER SUSQ VALLEY
FOR THE HEAVIEST RAIN...WITH 1+ INCH AMTS LIKELY BASED ON 21Z SREF
AND BLEND OF EARLIER OPER RUNS. MUCH LIGHTER AMTS EXPECTED ACROSS
THE NW MTNS.
HI RES MODELS INDICATING A SQUALL LINE TO ACCOMPANY SFC COLD
FRONT LAGGING THE UPPER FRONTAL PASSAGE WEDNESDAY EVENING. EXTENT
OF SURFACE DESTABILIZATION WILL ULTIMATELY DETERMINE HOW STRONG
THIS SQUALL LINE CAN GET...AND HOW STRONG WIND GUSTS CAN BE AT THE
SURFACE...BUT SUFFICE TO SAY ONE OF THE BETTER SEVERE WEATHER
SETUPS FOR CHRISTMAS EVE IS IN STORE FROM EARLY WED EVENING
THROUGH JUST PAST MIDNIGHT ACROSS CENTRAL PA. AS PREVIOUSLY
MENTIONED...EVEN MINIMAL CAPE COMBINED WITH STRONG /DEEP-LAYER
WIND FIELDS A FEW TO SVRL KFT AGL OFTEN RESULTS IN A NCFRB WITH
LOCALIZED DOWNBURST DAMAGE OCCURRING BENEATH MINI BOWS IN THE
LINE. SPC HAS PLACED MUCH OF CENTRAL PA IN MARGINAL CATEGORY FOR
DAY 2 AS A RESULT. MORE DETAILS BELOW.
TEMPERATURES WILL CLIMB INTO THE 50S WED AFTERNOON INTO WED
NIGHT...AS STRONGER SOUTHERLY WINDS DEVELOP. HAVE LOWERED DAYTIME
TEMPS OVR MUCH OF THE AREA...BASED ON LATEST GUIDANCE WHICH
INDICATES PERSISTENT COLD AIR DAMMING. THE WARMEST READINGS OVR
MUCH OF THE AREA MAY NOT BE REACHED UNTIL AFTER DARK WED EVENING.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
ANOMALOUSLY STRONG SSWRLY UPPER JET OF 140-150 KTS WILL ACCOMPANY
THE CFROPA IN THE 04-10Z TIME PERIOD CHRISTMAS DAY. IN
ADDITION...THE UNSEASONABLY WARM AND MOIST AIR WILL HELP TO
PRODUCE A RIBBON OF CAPE UP TO A FEW HUNDRED J/KG.
FOR NOW...HAVE CHC OF THUNDER IN FOR WED EVENING. NORMALLY I WOULD
BE MORE CONCERN ABOUT STRONG TO SEVERE STORMS...BUT BEST FORCING
ACROSS THE OH VLY. ALSO TIME OF DAY NOT THE BEST. HOWEVER...HINTS
OF COLD AIR DAMMING STILL ACROSS CENTRAL ZONES. EITHER
WAY...NORMALLY LIKE TO SEE DEWPTS IN THE UPPER 50S.
STILL EXPECT SOME GUSTY WINDS LATE WED NIGHT INTO THU AM...MOST
LIKELY WILL NEED A WIND ADVISORY...BUT STILL THIRD PERIOD.
TOOK SNOW OUT OF FCST FOR CHRISTMAS...TEMPS NOT COLD ENOUGH.
FRIDAY LOOKS NICE...WITH SW FLOW.
DID UP TEMPS FRIDAY INTO SAT...GIVEN RISING HEIGHTS.
CUT BACK PCPN FOR LATE FRIDAY.
12Z EC RUN HAS SYSTEM FURTHER NW NOW...BUT FOR NOW WENT WITH
SLIGHT CHC OF SNOW FROM SUNDAY INTO EARLY MONDAY MORNING.
AGAIN WITH SPLIT FLOW...THERE COULD BE SOME CHANCE FOR A SOUTHERN
WAVE TO BRING SOME RAIN OR SNOW SHOWERS TO THE AREA AT TIMES...BUT
IT LOOKS LIKE ANYTHING WOULD BE FAST MOVING. PERHAPS A CHANGE
LATER NEXT WEEK...AS CROSS POLAR FLOW SETS UP.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
WIDESPREAD REDUCTIONS WILL CONTINUE OVERNIGHT WITH ENTIRE CWA
REMAINING AT IFR/LIFR AS LOW LEVEL MOISTURE FEEDS IN FROM THE SE
FROM A WEAK SFC LOW EAST IF NEW JERSEY COAST...THEN MAINTAINED
AHEAD OF SRLY FLOW OF APPROACHING FRONTAL SYSTEM.
INCLUDED LLWS FOR ALL TAF SITES STARTING NEAR SUNRISE WED MORNING
AS WINDS ALOFT BEING TO INCREASE AHEAD OFF APPROACHING FRONTAL
SYSTEM OVER THE MIDWEST WHILE SFC WINDS REMAIN SERLY.
OUTLOOK...
WED...PERIODS OF RAIN ALONG WITH WIDESPREAD REDUCTIONS. SLGT CHC
TSTM NW. BREEZY. LLWS LIKELY.
THU...WINDY AND COLDER WITH SCT MVFR CIGS AND -SHSN. LLWS.
FRI...FAIR AND MOSTLY VFR.
SAT...FAIR AND MOSTLY VFR. SCT SHSN WITH LOCAL REDUCTIONS NW.
SUN...MVFR TO IFR WITH CHC RA/SN...ESP SOUTH.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR/MARTIN
NEAR TERM...FITZGERALD
SHORT TERM...DEVOIR/FITZGERALD
LONG TERM...MARTIN
AVIATION...GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1259 PM EST MON DEC 22 2014
.SYNOPSIS...
HIGH PRESSURE WILL RETREAT NORTHEAST INTO THE CANADIAN MARITIMES
EARLY THIS WEEK...AS A WEAK LOW PRESSURE SYSTEM LIFTS UP THE MID
ATLANTIC COAST. AN INTENSIFYING STORM SYSTEM WILL TRACK WEST OF
PENNSYLVANIA WEDNESDAY NIGHT...PUSHING A COLD FRONT THROUGH
THE STATE. ANOTHER LESS POTENT COLD FRONT IS LIKELY TO IMPACT THE
REGION BY NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MOISTURE SLOWLY INCREASING NORTH OF THE MASON DIXON LINE AS
MARITIME INFLUENCE INCREASES ACROSS SOUTHERN AND EASTERN PA. AT 1
PM...FZDZ/DZ IS NEARING THE KHGR AREA WITH SFC TEMPS THERE AT 34F
(TD 25F). BLEND OF THESE TRENDS PLUS THE LATEST HI RES HRRR AND
4KM HRW ARW SAYS POCKETS OF FZDZ AND FZRA ARE POSSIBLE FROM EARLY
AFTERNOON ONWARD LIFTING NORTH OF THE MD BORDER AND COVERING MUCH
OF THE SOUTH CENTRAL MOUNTAINS AFT 20Z. BEST ICING CHANCES ARE LATE
THIS AFTERNOON IN THESE AREAS...LIFTING NORTHWARD INTO THE
LAURELS AND NORTHERN PARTS OF THE SOUTH CENTRAL MOUNTAINS BEFORE
DARK.
FZRA ADVISORIES IN EFFECT FOR THE LAURELS AND SOUTH CENTRAL
MOUNTAINS...ALTHOUGH WESTERN PORTIONS OF THE LAURELS MAY BE LEFT
OUT OF THE PRECIP FOR SEVERAL HOURS (UNTIL WELL PAST DARK).
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
MOIST SERLY FLOW OFF THE ATLANTIC AND ASSOC OROGRAPHIC FORCING OF
SHALLOW MOISTURE LYR WILL LIKELY PRODUCE PATCHY LGT RAIN/DRIZZLE
TONIGHT AND TUESDAY. BEST CHC OF MEASURABLE PRECIP SHOULD COME
BTWN 00Z-06Z THIS EVENING WITH BENEFIT OF LG SCALE FORCING AHEAD
OF MID LVL SHORTWAVE. SFC TEMP FIELDS OF BOTH OPER AND ENSEMBLE
DATA SUGGEST THERE COULD BE ICING CONCERNS OVER THE HIGHER TERRAIN
OF CENTRAL PA. HOWEVER...TEMPS WILL BE VERY MARGINAL WITH ICING
MOST LIKELY ON THE RIDGETOPS. ALSO...NOT ENTIRELY SURE MEASURABLE
PRECIP WILL EVEN REACH FAR ENOUGH WEST TO CREATE A CONCERN. WILL
THEREFORE CONTINUE TO MENTION THREAT OF ICY ROADS IN THE HWO AND
AWAIT 12Z GUIDANCE TO GET A BETTER HANDLE ON THIS EVENT.
ANY ICING THREAT SHOULD END BY DAYLIGHT TUESDAY...WHEN ALL PLUME
MEMBERS RISE ABV FREEZING. RAINFALL AMTS TUESDAY SHOULD BE VERY
LIGHT...WITH SHALLOW MOISTURE IN MDL SOUNDINGS IMPLYING OCNL
DRIZZLE RATHER THAN RAIN.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE MOST SIGNIFICANT FORECAST ISSUE IN THE LONG TERM REMAINS THE
EVOLUTION OF DEEP TROUGH AND ASSOC SFC LOW TRACKING WEST OF PA
WED/WED NITE. STRONG SOUTHERLY FLOW AHEAD OF THIS SYSTEM SHOULD SCOUR
OUT LINGERING SHALLOW COLD AIR EAST OF THE APPALACHIANS. LOW-LEVEL
TEMPERATURE AND MOISTURE FIELDS RISE WELL ABOVE THEIR SEASONAL
VALUES...IMPLYING IT WILL BE A BALMY CHRISTMAS EVE FOR ALL.
ALL MED RANGE GUIDANCE TIMES THE TRAILING COLD FRONT THRU CENTRAL
PA WED NITE. A STRONG SOUTHERLY LL JET AND ASSOC PWAT ANOMALIES
ABOUT +3 SIGMA ABOVE NORMAL ARE PROGGED BY GEFS TO PASS THRU THE
AREA IN ADVANCE OF THE FRONT WED NITE. THIS STRONG SOUTHERLY
FLOW...HIGH PRECIPITABLE WATER AND SHARP CDFRONT ALL IMPLY A
FRONTAL RAIN EVENT WITH PERHAPS SOME RARE LATE DECEMBER (ELEVATED)
CONVECTION. HAVE ADDED CHC OF THUNDER BASED ON EXPECTED STRONG LG
SCALE FORCING IN ADVANCE OF UPPER TROF AND PRESENCE OF SOME MEAGER
MDL CAPES.
INTENSIFYING SFC LOW PASSING NORTH OF PA IS A FAVORABLE PATTERN
FOR STRONG WINDS ACROSS CENTRAL PA DURING THE COLD SEASON...SO STILL
MONITORING THE POTENTIAL OF STRONG WINDS COINCIDENT AND FOLLOWING
PASSAGE OF CDFRONT LATE WED NITE AND THURSDAY. WILL MENTION
POTENTIAL IN HWO.
COLDER AIR WORKING IN BEHIND COLD FRONT WILL LIKELY PRODUCE
OROGRAPHIC SNOW SHOWERS ACROSS THE ALLEGHENY PLATEAU ON CHRISTMAS
DAY. HOWEVER...AIR MASS NOT LOOKING PARTICULARLY COLD AND SFC
TEMPS LIKELY TO BE ABV FREEZING...LIMITING THE POTENTIAL OF
ACCUMS.
TEMPERATURES SHOULD REBOUND FRIDAY AHEAD OF ANOTHER NORTHERN STREAM
WAVE MOVING INTO THE MID-WEST. ECENS OUTPUT SUGGESTS THIS
SHORTWAVE WILL LIFT NORTH OF PA NEXT WEEKEND...PUSHING A DYING COLD
FRONT INTO THE REGION.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
COMBINATION OF RETREATING HIGH PRES OVR THE CANADIAN MARITIMES AND
WEAK LOW LIFTING UP THE MID ATLANTIC COAST WILL SPREAD AN
INCREASINGLY MOIST SERLY FLOW INTO CENTRAL PA ON TODAY. LOWER CIGS
LIFTING NORTHWARD THIS MORNING IN RESPONSE TO DEEPENING LLVL
MOISTURE AND ONSHORE FLOW. THE INCREASING MOISTURE...COMBINED
WITH LG SCALE FORCING AHEAD OF SHORTWAVE LIFTING OUT THE SE
STATES...COULD SPREAD A BIT OF LIGHT RAIN INTO SOUTHERN PA LATE
THIS AFTN.
MAIN CONCERN WILL BE POTENTIAL OF SOME LIGHT ICING...GIVEN COLD
AIR DAMMING SIGNATURE AND IMPLIED LOW-LEVEL AGEOSTROPHIC NORTHERLY
FLOW HOLDING LOW-LEVEL COLD AIR IN. OPER MDL SOUNDINGS AND ENS
PTYPES SUGGEST THE BEST CHC OF LATE DAY LIGHT -FZRA WOULD BE OVR
THE LAUREL HIGHLANDS AND HIGHER TERRAIN OF THE SC MTNS...WITH A
BETTER CHANCE TONIGHT ACROSS THE CENTRAL MTNS.
OUTLOOK...
TUE...LOW CIGS WITH DRIZZLE/LIGHT RAIN LIKELY. BECOMING BREEZY
MAINLY ACROSS HIGHER TERRAIN. LLWS POSS N/W.
WED...PERIODS OF RAIN ALONG WITH WIDESPREAD REDUCTIONS. BREEZY.
LLWS LIKELY.
THU...WINDY AND COLDER WITH SCT MVFR CIGS AND -SHSN. LLWS.
FRI...FAIR AND MOSTLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
PAZ024>028-033>036-056-063-064.
FREEZING RAIN ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ065.
&&
$$
SYNOPSIS...DEVOIR/FITZGERALD
NEAR TERM...DEVOIR/FITZGERALD
SHORT TERM...DEVOIR/FITZGERALD
LONG TERM...FITZGERALD
AVIATION...DEVOIR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1112 AM EST MON DEC 22 2014
.SYNOPSIS...
HIGH PRESSURE WILL RETREAT NORTHEAST INTO THE CANADIAN MARITIMES
EARLY THIS WEEK...AS A WEAK LOW PRESSURE SYSTEM LIFTS UP THE MID
ATLANTIC COAST. AN INTENSIFYING STORM SYSTEM WILL TRACK WEST OF
PENNSYLVANIA WEDNESDAY NIGHT...PUSHING A COLD FRONT THROUGH
THE STATE. ANOTHER LESS POTENT COLD FRONT IS LIKELY TO IMPACT THE
REGION BY NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
16Z UPDATE** COLLAB WITH LWX AND PBZ ON ISSUING WSW ADVISORY FOR
FREEZING RAIN OVER LAURELS AND SOUTH CENTRAL MOUNTAINS.
LOW CLOUDS LIFTING CENTRAL MOUNTAINS AT MID MORNING
WITH DEEPER MOISTURE STARTING TO POOL SOUTH OF THE MASON DIXON
LINE...IN RESPONSE TO INCREASING MARITIME INFLUENCE IN INCREASING
EASTERLY/ONSHORE FLOW BETWEEN CAPE HATTERAS LOW PRESSURE AND
NORTHERN NEW ENGLANHIGH PRESSURE. THE INCREASING
MOISTURE...COMBINED WITH LG SCALE FORCING AHEAD OF SHORTWAVE
LIFTING OUT THE SE STATES...COULD SPREAD A BIT OF LIGHT RAIN INTO
SOUTHERN PA THIS AFTN. BLEND OF LATEST MDL GUIDANCE SUPPORTS CHC
POPS ACROSS THE SOUTHERN COUNTIES THIS AFTN.
FOR THE DAY...THE MAIN CONCERN FOCUSES ON POTENTIAL OF SOME ICING
LATER ON... GIVEN COLD AIR DAMMING AND LLVL AGEOSTROPHIC NLY FLOW
LOCKING THE COLD AIR IN. LATEST HRRR AND 4KM HRW-ARW DIFFER
SIGNIFICANTLY ON ARRIVAL OF PRECIP INTO SOUTH CENTRAL PA. LATEST
HRW-ARW HAS COME INTO LINE WITH PREVIOUS HRRR HOWEVER...IN
DELAYING PRECIP UNTIL AFTER 20Z...AND MOST OF THAT BEING RAIN
OVERF THE LOWER SUSQ RIVER VALLEY.
THUS...LATEST HI RES RUNS...FORECAST SOUNDINGS AND ENS PTYPES
SUGGEST THE BEST ICING CHANCE LATE THIS AFTERNOON...STARTING NEAR
THE MASON DIXON LINE MID TO LATE AFTERNOON...AND LIFTING NORTHWARD
INTO THE LAURELS AND SOUTH CENTRAL MOUNTAINS BEFORE DARK.
STILL NO ADVY TO BE POSTED AT THIS TIME DUE TO THE LOW CERTAINTY
OF MEASURABLE FZRA...BUT CONFIDENCE INCREASING FROM ADAMS COUNTY
WESTWARD THAT AN ADVISORY MAY BE NEEDED FROM ADAMS COUNTY WESTWARD
MID TO LATE AFTERNOON. WILL MONITOR TRENDS AND ISSUE ACCORDINGLY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
MOIST SERLY FLOW OFF THE ATLANTIC AND ASSOC OROGRAPHIC FORCING OF
SHALLOW MOISTURE LYR WILL LIKELY PRODUCE PATCHY LGT RAIN/DRIZZLE
TONIGHT AND TUESDAY. BEST CHC OF MEASURABLE PRECIP SHOULD COME
BTWN 00Z-06Z THIS EVENING WITH BENEFIT OF LG SCALE FORCING AHEAD
OF MID LVL SHORTWAVE. SFC TEMP FIELDS OF BOTH OPER AND ENSEMBLE
DATA SUGGEST THERE COULD BE ICING CONCERNS OVER THE HIGHER TERRAIN
OF CENTRAL PA. HOWEVER...TEMPS WILL BE VERY MARGINAL WITH ICING
MOST LIKELY ON THE RIDGETOPS. ALSO...NOT ENTIRELY SURE MEASURABLE
PRECIP WILL EVEN REACH FAR ENOUGH WEST TO CREATE A CONCERN. WILL
THEREFORE CONTINUE TO MENTION THREAT OF ICY ROADS IN THE HWO AND
AWAIT 12Z GUIDANCE TO GET A BETTER HANDLE ON THIS EVENT.
ANY ICING THREAT SHOULD END BY DAYLIGHT TUESDAY...WHEN ALL PLUME
MEMBERS RISE ABV FREEZING. RAINFALL AMTS TUESDAY SHOULD BE VERY
LIGHT...WITH SHALLOW MOISTURE IN MDL SOUNDINGS IMPLYING OCNL
DRIZZLE RATHER THAN RAIN.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE MOST SIGNIFICANT FORECAST ISSUE IN THE LONG TERM REMAINS THE
EVOLUTION OF DEEP TROUGH AND ASSOC SFC LOW TRACKING WEST OF PA
WED/WED NITE. STRONG SOUTHERLY FLOW AHEAD OF THIS SYSTEM SHOULD SCOUR
OUT LINGERING SHALLOW COLD AIR EAST OF THE APPALACHIANS. LOW-LEVEL
TEMPERATURE AND MOISTURE FIELDS RISE WELL ABOVE THEIR SEASONAL
VALUES...IMPLYING IT WILL BE A BALMY CHRISTMAS EVE FOR ALL.
ALL MED RANGE GUIDANCE TIMES THE TRAILING COLD FRONT THRU CENTRAL
PA WED NITE. A STRONG SOUTHERLY LL JET AND ASSOC PWAT ANOMALIES
ABOUT +3 SIGMA ABOVE NORMAL ARE PROGGED BY GEFS TO PASS THRU THE
AREA IN ADVANCE OF THE FRONT WED NITE. THIS STRONG SOUTHERLY
FLOW...HIGH PRECIPITABLE WATER AND SHARP CDFRONT ALL IMPLY A
FRONTAL RAIN EVENT WITH PERHAPS SOME RARE LATE DECEMBER (ELEVATED)
CONVECTION. HAVE ADDED CHC OF THUNDER BASED ON EXPECTED STRONG LG
SCALE FORCING IN ADVANCE OF UPPER TROF AND PRESENCE OF SOME MEAGER
MDL CAPES.
INTENSIFYING SFC LOW PASSING NORTH OF PA IS A FAVORABLE PATTERN
FOR STRONG WINDS ACROSS CENTRAL PA DURING THE COLD SEASON...SO STILL
MONITORING THE POTENTIAL OF STRONG WINDS COINCIDENT AND FOLLOWING
PASSAGE OF CDFRONT LATE WED NITE AND THURSDAY. WILL MENTION
POTENTIAL IN HWO.
COLDER AIR WORKING IN BEHIND COLD FRONT WILL LIKELY PRODUCE
OROGRAPHIC SNOW SHOWERS ACROSS THE ALLEGHENY PLATEAU ON CHRISTMAS
DAY. HOWEVER...AIR MASS NOT LOOKING PARTICULARLY COLD AND SFC
TEMPS LIKELY TO BE ABV FREEZING...LIMITING THE POTENTIAL OF
ACCUMS.
TEMPERATURES SHOULD REBOUND FRIDAY AHEAD OF ANOTHER NORTHERN STREAM
WAVE MOVING INTO THE MID-WEST. ECENS OUTPUT SUGGESTS THIS
SHORTWAVE WILL LIFT NORTH OF PA NEXT WEEKEND...PUSHING A DYING COLD
FRONT INTO THE REGION.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
COMBINATION OF RETREATING HIGH PRES OVR THE CANADIAN MARITIMES AND
WEAK LOW LIFTING UP THE MID ATLANTIC COAST WILL SPREAD AN
INCREASINGLY MOIST SERLY FLOW INTO CENTRAL PA ON TODAY. LOWER CIGS
LIFTING NORTHWARD THIS MORNING IN RESPONSE TO DEEPENING LLVL
MOISTURE AND ONSHORE FLOW. THE INCREASING MOISTURE...COMBINED
WITH LG SCALE FORCING AHEAD OF SHORTWAVE LIFTING OUT THE SE
STATES...COULD SPREAD A BIT OF LIGHT RAIN INTO SOUTHERN PA LATE
THIS AFTN.
MAIN CONCERN WILL BE POTENTIAL OF SOME LIGHT ICING...GIVEN COLD
AIR DAMMING SIGNATURE AND IMPLIED LOW-LEVEL AGEOSTROPHIC NORTHERLY
FLOW HOLDING LOW-LEVEL COLD AIR IN. OPER MDL SOUNDINGS AND ENS
PTYPES SUGGEST THE BEST CHC OF LATE DAY LIGHT -FZRA WOULD BE OVR
THE LAUREL HIGHLANDS AND HIGHER TERRAIN OF THE SC MTNS...WITH A
BETTER CHANCE TONIGHT ACROSS THE CENTRAL MTNS.
OUTLOOK...
TUE...LOW CIGS WITH DRIZZLE/LIGHT RAIN LIKELY. BECOMING BREEZY
MAINLY ACROSS HIGHER TERRAIN. LLWS POSS N/W.
WED...PERIODS OF RAIN ALONG WITH WIDESPREAD REDUCTIONS. BREEZY.
LLWS LIKELY.
THU...WINDY AND COLDER WITH SCT MVFR CIGS AND -SHSN. LLWS.
FRI...FAIR AND MOSTLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
PAZ024>028-033>036-056-063-064.
FREEZING RAIN ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ065.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...DEVOIR/FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...DEVOIR/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1025 AM EST MON DEC 22 2014
.SYNOPSIS...
HIGH PRESSURE WILL RETREAT NORTHEAST INTO THE CANADIAN MARITIMES
EARLY THIS WEEK...AS A WEAK LOW PRESSURE SYSTEM LIFTS UP THE MID
ATLANTIC COAST. AN INTENSIFYING STORM SYSTEM WILL TRACK WEST OF
PENNSYLVANIA WEDNESDAY NIGHT...PUSHING A COLD FRONT THROUGH
THE STATE. ANOTHER LESS POTENT COLD FRONT IS LIKELY TO IMPACT THE
REGION BY NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
15Z UPDATE** LOW CLOUDS LIFTING CENTRAL MOUNTAINS AT MID
MORNING WITH DEEPER MOISTURE STARTING TO POOL SOUTH OF THE MASON
DIXON LINE...IN RESPONSE TO INCREASING MARITIME INFLUENCE IN
INCREASING EASTERLY/ONSHORE FLOW BETWEEN CAPE HATTERAS LOW
PRESSURE AND NORTHERN NEW ENGLANHIGH PRESSURE. THE INCREASING
MOISTURE...COMBINED WITH LG SCALE FORCING AHEAD OF SHORTWAVE
LIFTING OUT THE SE STATES...COULD SPREAD A BIT OF LIGHT RAIN INTO
SOUTHERN PA THIS AFTN. BLEND OF LATEST MDL GUIDANCE SUPPORTS CHC
POPS ACROSS THE SOUTHERN COUNTIES THIS AFTN.
FOR THE DAY...THE MAIN CONCERN FOCUSES ON POTENTIAL OF SOME ICING
LATER ON... GIVEN COLD AIR DAMMING AND LLVL AGEOSTROPHIC NLY FLOW
LOCKING THE COLD AIR IN. LATEST HRRR AND 4KM HRW-ARW DIFFER
SIGNIFICANTLY ON ARRIVAL OF PRECIP INTO SOUTH CENTRAL PA. LATEST
HRW-ARW HAS COME INTO LINE WITH PREVIOUS HRRR HOWEVER...IN
DELAYING PRECIP UNTIL AFTER 20Z...AND MOST OF THAT BEING RAIN
OVERF THE LOWER SUSQ RIVER VALLEY.
THUS...LATEST HI RES RUNS...FORECAST SOUNDINGS AND ENS PTYPES
SUGGEST THE BEST ICING CHANCE LATE THIS AFTERNOON...STARTING NEAR
THE MASON DIXON LINE MID TO LATE AFTERNOON...AND LIFTING NORTHWARD
INTO THE LAURELS AND SOUTH CENTRAL MOUNTAINS BEFORE DARK.
STILL NO ADVY TO BE POSTED AT THIS TIME DUE TO THE LOW CERTAINTY
OF MEASURABLE FZRA...BUT CONFIDENCE INCREASING FROM ADAMS COUNTY
WESTWARD THAT AN ADVISORY MAY BE NEEDED FROM ADAMS COUNTY WESTWARD
MID TO LATE AFTERNOON. WILL MONITOR TRENDS AND ISSUE ACCORDINGLY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
MOIST SERLY FLOW OFF THE ATLANTIC AND ASSOC OROGRAPHIC FORCING OF
SHALLOW MOISTURE LYR WILL LIKELY PRODUCE PATCHY LGT RAIN/DRIZZLE
TONIGHT AND TUESDAY. BEST CHC OF MEASURABLE PRECIP SHOULD COME
BTWN 00Z-06Z THIS EVENING WITH BENEFIT OF LG SCALE FORCING AHEAD
OF MID LVL SHORTWAVE. SFC TEMP FIELDS OF BOTH OPER AND ENSEMBLE
DATA SUGGEST THERE COULD BE ICING CONCERNS OVER THE HIGHER TERRAIN
OF CENTRAL PA. HOWEVER...TEMPS WILL BE VERY MARGINAL WITH ICING
MOST LIKELY ON THE RIDGETOPS. ALSO...NOT ENTIRELY SURE MEASURABLE
PRECIP WILL EVEN REACH FAR ENOUGH WEST TO CREATE A CONCERN. WILL
THEREFORE CONTINUE TO MENTION THREAT OF ICY ROADS IN THE HWO AND
AWAIT 12Z GUIDANCE TO GET A BETTER HANDLE ON THIS EVENT.
ANY ICING THREAT SHOULD END BY DAYLIGHT TUESDAY...WHEN ALL PLUME
MEMBERS RISE ABV FREEZING. RAINFALL AMTS TUESDAY SHOULD BE VERY
LIGHT...WITH SHALLOW MOISTURE IN MDL SOUNDINGS IMPLYING OCNL
DRIZZLE RATHER THAN RAIN.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE MOST SIGNIFICANT FORECAST ISSUE IN THE LONG TERM REMAINS THE
EVOLUTION OF DEEP TROUGH AND ASSOC SFC LOW TRACKING WEST OF PA
WED/WED NITE. STRONG SOUTHERLY FLOW AHEAD OF THIS SYSTEM SHOULD SCOUR
OUT LINGERING SHALLOW COLD AIR EAST OF THE APPALACHIANS. LOW-LEVEL
TEMPERATURE AND MOISTURE FIELDS RISE WELL ABOVE THEIR SEASONAL
VALUES...IMPLYING IT WILL BE A BALMY CHRISTMAS EVE FOR ALL.
ALL MED RANGE GUIDANCE TIMES THE TRAILING COLD FRONT THRU CENTRAL
PA WED NITE. A STRONG SOUTHERLY LL JET AND ASSOC PWAT ANOMALIES
ABOUT +3 SIGMA ABOVE NORMAL ARE PROGGED BY GEFS TO PASS THRU THE
AREA IN ADVANCE OF THE FRONT WED NITE. THIS STRONG SOUTHERLY
FLOW...HIGH PRECIPITABLE WATER AND SHARP CDFRONT ALL IMPLY A
FRONTAL RAIN EVENT WITH PERHAPS SOME RARE LATE DECEMBER (ELEVATED)
CONVECTION. HAVE ADDED CHC OF THUNDER BASED ON EXPECTED STRONG LG
SCALE FORCING IN ADVANCE OF UPPER TROF AND PRESENCE OF SOME MEAGER
MDL CAPES.
INTENSIFYING SFC LOW PASSING NORTH OF PA IS A FAVORABLE PATTERN
FOR STRONG WINDS ACROSS CENTRAL PA DURING THE COLD SEASON...SO STILL
MONITORING THE POTENTIAL OF STRONG WINDS COINCIDENT AND FOLLOWING
PASSAGE OF CDFRONT LATE WED NITE AND THURSDAY. WILL MENTION
POTENTIAL IN HWO.
COLDER AIR WORKING IN BEHIND COLD FRONT WILL LIKELY PRODUCE
OROGRAPHIC SNOW SHOWERS ACROSS THE ALLEGHENY PLATEAU ON CHRISTMAS
DAY. HOWEVER...AIR MASS NOT LOOKING PARTICULARLY COLD AND SFC
TEMPS LIKELY TO BE ABV FREEZING...LIMITING THE POTENTIAL OF
ACCUMS.
TEMPERATURES SHOULD REBOUND FRIDAY AHEAD OF ANOTHER NORTHERN STREAM
WAVE MOVING INTO THE MID-WEST. ECENS OUTPUT SUGGESTS THIS
SHORTWAVE WILL LIFT NORTH OF PA NEXT WEEKEND...PUSHING A DYING COLD
FRONT INTO THE REGION.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
COMBINATION OF RETREATING HIGH PRES OVR THE CANADIAN MARITIMES AND
WEAK LOW LIFTING UP THE MID ATLANTIC COAST WILL SPREAD AN
INCREASINGLY MOIST SERLY FLOW INTO CENTRAL PA ON TODAY. LOWER CIGS
LIFTING NORTHWARD THIS MORNING IN RESPONSE TO DEEPENING LLVL
MOISTURE AND ONSHORE FLOW. THE INCREASING MOISTURE...COMBINED
WITH LG SCALE FORCING AHEAD OF SHORTWAVE LIFTING OUT THE SE
STATES...COULD SPREAD A BIT OF LIGHT RAIN INTO SOUTHERN PA LATE
THIS AFTN.
MAIN CONCERN WILL BE POTENTIAL OF SOME LIGHT ICING...GIVEN COLD
AIR DAMMING SIGNATURE AND IMPLIED LOW-LEVEL AGEOSTROPHIC NORTHERLY
FLOW HOLDING LOW-LEVEL COLD AIR IN. OPER MDL SOUNDINGS AND ENS
PTYPES SUGGEST THE BEST CHC OF LATE DAY LIGHT -FZRA WOULD BE OVR
THE LAUREL HIGHLANDS AND HIGHER TERRAIN OF THE SC MTNS...WITH A
BETTER CHANCE TONIGHT ACROSS THE CENTRAL MTNS.
OUTLOOK...
TUE...LOW CIGS WITH DRIZZLE/LIGHT RAIN LIKELY. BECOMING BREEZY
MAINLY ACROSS HIGHER TERRAIN. LLWS POSS N/W.
WED...PERIODS OF RAIN ALONG WITH WIDESPREAD REDUCTIONS. BREEZY.
LLWS LIKELY.
THU...WINDY AND COLDER WITH SCT MVFR CIGS AND -SHSN. LLWS.
FRI...FAIR AND MOSTLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...DEVOIR/FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...RXR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
237 PM MST MON DEC 22 2014
.SHORT TERM...THIS EVENING THROUGH TUESDAY NIGHT
ISSUED AT 230 PM MST MON DEC 22 2014
UPPER LOW IS CENTERED OVER SD...WITH SURFACE LOW OVER
NORTHEAST SD. RAIN/SNOW IS WRAPPING AROUND THE LOW INTO WESTERN SD.
A TIGHT PRESSURE GRADIENT IS KEEPING NORTHWEST WINDS STRONG THIS
AFTERNOON...ESPECIALLY JUST EAST OF THE HILLS. TEMPS ARE IN THE 30S
TO LOW 40S.
WINDS WILL BECOME MORE NORTHERLY TONIGHT AS THE LOW SLIDES
SOUTHEASTWARD. STRONG WINDS OF 25-35 KTS WITH HIGHER GUSTS ARE STILL
EXPECTED THROUGH THE NIGHT...WITH THE STRONGEST WINDS GRADUALLY
SHIFTING SOUTHWARD. TWEAKED THE ADVISORIES TO CONVERT RAPID CITY AND
CUSTER COUNTY PLAINS TO WINTER WEATHER ADVISORIES FOR BLOWING SNOW
THIS EVENING AFTER THOSE AREAS RECEIVE SNOW. EXTENDED THE WIND
ADVISORY FOR THE SOUTHEASTERN FOOTHILLS AND THE FALL RIVER PLAINS
THROUGH TUESDAY MORNING. WILL LET SOUTHERN FOOTHILLS WIND ADVISORY
EXPIRE THIS EVENING...AS DO NOT EXPECT AS STRONG WINDS THERE WITH
THE MORE NORTHERLY DIRECTION.
MOST OF THE SNOW WILL FALL OVERNIGHT...AND TOTAL AMOUNTS HAVE NOT
CHANGED MUCH FROM PREVIOUS FORECAST. LOOKS LIKE AN ADDITIONAL 6 TO 9
INCHES IS POSSIBLE IN THE NORTHERN HILLS...WITH ABOUT 3 TO 5 INCHES
ON THE SD PLAINS...POSSIBLY MORE AROUND THE SHANNON/JACKSON/BENNETT
COUNTY AREAS. FOR THE RAPID CITY AREA...1-3 INCHES STILL LOOKS ON
TRACK. THREAT OF MOST CONCERN WILL BE THE REDUCED VISIBILITIES DUE
TO BLOWING SNOW...WHICH COULD RESULT IN WHITE-OUT CONDITIONS AT
TIMES. CONSIDERED A WARNING FOR THE SHANNON/JACKSON/BENNETT
AREAS...BUT MAINLY FOR BLOWING SNOW. WINDS DO NOT LOOK INCREDIBLY
STRONG THERE...AND ALTHOUGH SNOW AMOUNTS MAY APPROACH WINTER STORM
WARNING CRITERIA...THINK THE WINTER WEATHER ADVISORY SHOULD COVER
THE THREAT FOR BLOWING SNOW.
BREEZY WINDS WILL CONTINUE ON TUESDAY...AND SNOW WILL LINGER LONGEST
OVER SOUTH CENTRAL SD. SKIES WILL GRADUALLY CLEAR FROM WEST TO
EAST...AND HIGHS WILL BE IN THE 30S. LOWS TUESDAY NIGHT WILL BE IN
THE TEENS.
.LONG TERM...WEDNESDAY THROUGH MONDAY
ISSUED AT 230 PM MST MON DEC 22 2014
ALTHOUGH EXTENDED PERIOD STARTS UNDER UPPER RIDGING...
LONG WAVE TROF DEEPENS OVER THE WESTERN US...INFLUENCING THE WEATHER
OVER THE PLAINS THROUGH THE WEEK BEFORE MOVING EASTWARD AND NEXT
SYSTEM MOVES ONSHORE. BROAD RIDGE WILL BE IN PLACE OVER THE ROCKIES
AND NORTHERN PLAINS WED WHILE SURFACE LOW TRACKS ACROSS SOUTHERN
CANADA WITH A WARM FRONT MOVING NORTH. FORECAST AREA WILL BE IN THE
WARM SECTOR WITH SOUTHWEST WINDS AND PARTLY CLOUDY SKIES...WHICH
WILL WARM TEMPERATURES INTO THE 40S OVER FAR SOUTHWESTERN SD AND THE
NORTHERN AND EASTERN SLOPES OF THE BLACK HILLS. WITH POTENTIAL
SNOWFALL FROM CURRENT STORM...TEMPERATURES PROBABLY WILL NOT GET
INTO THE 50S. COLD FRONT WILL DROP ACROSS THE AREA LATE ON CHRISTMAS
EVE. AS TROF MOVES OVER THE ROCKIES...PRECIPITATION WILL SPREAD
NORTHEASTWARD AHEAD OF IT...WITH MODELS CONVERGING ON THE SURFACE
LOW TRACK ACROSS THE CENTRAL PLAINS INTO THE MISSOURI RIVER
VALLEY...WHICH WOULD GIVE SOUTH CENTRAL SD THE MOST SNOW.
PRECIPITATION SHOULD BE JUST SNOW AS AIRMASS IS DRY WHEN FORECAST
SOUNDINGS SHOW TEMPERATURES ABOVE FREEZING...BUT COOLS QUICKLY
BEHIND COLD FRONT BEFORE BECOMING SATURATED AND BETTER DYNAMICS
REACH THE AREA. TROF CLEARS THE AREA FRIDAY MORNING. AN ALBERTA
CLIPPER SYSTEM DROPS ACROSS THE NORTHERN PLAINS LATE FRIDAY...GFS
SHOWS IT WEAK WITH VIRTUALLY NO QPF...BUT ECMWF HAS A STRONGER
SOLUTION...SO POPS MAY INCREASE IN SUBSEQUENT FORECASTS. ARCTIC HIGH
WILL PUSH SOUTHWARD...WITH MUCH COOLER TEMPERATURES FRIDAY. ANOTHER
ARCTIC HIGH WILL FORCE A BACKDOOR COLD FRONT WESTWARD OVER THE
AREA...WITH EVEN COOLER TEMPERATURES. NEXT SYSTEM DEEPENS AS IT
MOVES FROM THE PACIFIC NORTHWEST INTO THE GREAT BASIN...WITH MORE
SNOW POSSIBLE EARLY NEXT WEEK.
&&
.AVIATION...FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING
ISSUED AT 230 PM MST MON DEC 22 2014
SNOW IS INCRSG OVR WRN SD THIS AFTN...WITH CIGS/VSBY
LOWERING. EXPECT MVFR/IFR CONDITIONS OVER MOST PLACES XCPT
DOWNSLOPED AREAS FROM RAP TO HSR. GUSTY NW WINDS WILL CONTINUE THRU
THE NIGHT...LEADING TO LWR VSBYS IN BLOWING SNOW. SNOW AND WNDS WL
DCRS TUESDAY MORNING AND CIGS/VIS WILL GRADUALLY IMPROVE THRU THE
DAY.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WARNING UNTIL NOON MST TUESDAY FOR SDZ024-025.
WINTER WEATHER ADVISORY UNTIL NOON MST TUESDAY FOR SDZ013-014-
028-031-032-042>044-072-073.
WINTER WEATHER ADVISORY UNTIL 6 PM CST TUESDAY FOR SDZ046-047-
049.
WIND ADVISORY UNTIL NOON MST TUESDAY FOR SDZ041-074.
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR SDZ001-002-
012.
WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO NOON MST
TUESDAY FOR SDZ026-030.
WIND ADVISORY UNTIL 8 PM MST THIS EVENING FOR SDZ027-030.
HIGH WIND WARNING UNTIL 8 PM MST THIS EVENING FOR SDZ026.
WY...WINTER STORM WARNING UNTIL NOON MST TUESDAY FOR WYZ057.
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR WYZ056-071.
&&
$$
SHORT TERM...POJORLIE
LONG TERM...55
AVIATION...55
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1147 PM CST SUN DEC 21 2014
.UPDATE...
ISSUED AT 935 PM CST SUN DEC 21 2014
HAVE OVERHAULED POPS AND WEATHER SOME MAINLY TO SLOW DOWN THE
SPREAD OF PRECIPITATION SPRE4D OVER THE NORTHERN PART OF THE AREA
AND TO LOWER THE OVERALL CHANCE FAR WEST/NORTHWEST. STILL...LIGHT
RAIN AT MID EVENING WAS SPREADING OVER THE MISSOURI RIVER AREA AND
SHOULD CONTINUE TO DEVELOP NORTHEAST THROUGH THE NIGHT. SLIGHT
ADJUSTMENTS TO TEMPERATURES AND TO THE NATURE OF ANY SLEET/SNOW
MIXTURE FAR NORTH AND WEST LATER TONIGHT. OVERALL HOWEVER NOT TOO
MUCH CHANGE....WITH MOST OF THE PRECIPITATION TONIGHT STILL BEING
LIGHT RAIN.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 323 PM CST SUN DEC 21 2014
CLEARING LINE HAS MADE SOME PROGRESS EAST THIS AFTERNOON. HOWEVER BY
LATE THIS AFTERNOON AND EVENING EXPECT THE LOW STRATUS TO RETURN
NORTHWEST AND COVER MUCH OF THE AREA YET AGAIN. HRRR AND RAP
GUIDANCE HAVE BEEN DOING PRETTY WELL THE PAST FEW NIGHTS...AND
SUGGEST DENSE FOG WILL PROBABLY NOT BE AS BIG OF AN ISSUE TONIGHT. A
STRONG UPPER WAVE WILL DIVE SOUTHEAST INTO THE PLAINS TONIGHT. STILL
QUITE THE SPREAD AMONG MODEL SOLUTIONS. NAM AND GFS ARE FURTHER
SOUTH WITH THE SYSTEM THAN THE ECMWF. ECMWF HAS BEEN THE MOST
CONSISTENT AND THE PARALLEL UPGRADED GFS IS MORE IN LINE WITH THE
ECMWF SOLUTION. THUS DECIDED TO WEIGH HEAVILY IN THAT DIRECTION FOR
THIS FORECAST. LIFT AHEAD OF THE WAVE WILL LIKELY GENERATE
PRECIPITATION TONIGHT...DEVELOPING IN THE WEST THIS EVENING...AND
SPREADING EAST THROUGH THE NIGHT. BASED ON MODEL SOUNDINGS AND
CONSENSUS RAW TEMPERATURES...BELIEVE THIS WILL MAINLY BE RAIN.
ALTHOUGH COULD SEE SOME SLEET MIXED IN...MAINLY WEST OF THE JAMES
RIVER.
MONDAY IS WHEN THE MODEL DIFFERENCES BEGIN TO HAVE A BIGGER IMPACT
ON THE FORECAST. THE FAVORED ECMWF AND PARALLEL GFS SOLUTION RESULTS
IN A DRY SLOT OVER MUCH OF THE CWA. THE MAJORITY OF THE WRAP AROUND
SNOW ASSOCIATED WITH THE DEVELOPING TROWAL SHOULD STAY NORTHWEST OF
THE CWA. DO THINK LOCATIONS FROM HURON TO CHAMBERLAIN COULD GET IN
ON SOME OF THIS ACTIVITY THOUGH. SOUNDINGS SUGGEST THAT BY MONDAY
ANY WARM LAYER IS SURFACE BASED...SUGGESTING EITHER RAIN OR SNOW
DEPENDING ON SURFACE TEMPERATURE. RAW MODEL CONSENSUS OF
TEMPERATURES SUGGESTS PTYPE STAYS PREDOMINATELY RAIN EAST OF THE
JAMES RIVER INTO THE AFTERNOON...WITH THE RAIN SNOW MIX GETTING TO
INTERSTATE 29 BY 0Z. BUT AS MENTIONED...MUCH OF THE CWA SHOULD SEE
VERY LIMITED QPF THROUGH THE DAY HOURS...WITH JUST SOME RAIN IN THE
FAR EAST AND AN INCH OR TWO OF SNOW FROM BRULE TO WESTERN BEADLE
COUNTY. WILL NEED TO MONITOR MODEL TRENDS...BECAUSE IF THE NAM AND
OPERATIONAL GFS FURTHER SOUTH SOLUTION VERIFIES...MORE OF THE CWA
WOULD SEE PRECIP ON MONDAY. BUT EVEN THEN THE WARM LOW LEVEL
TEMPERATURES WOULD LIKELY KEEP MOST AREAS RAIN FOR A MAJORITY OF THE
DAY KEEPING ANY SNOW ACCUMS DOWN.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 323 PM CST SUN DEC 21 2014
MONDAY NIGHT INTO TUESDAY WILL BE A PERIOD WHERE THE SYSTEM HAS
SLOWED DOWN JUST A BIT AND A FAIRLY PERSISTENT TROWAL SETS UP.
STRONG NORTH TO NORTHWEST WINDS WILL GRADUALLY DEVELOP THROUGH THE
DAY SO IT IS STARTING TO LOOK LIKE WE MAY NEED AND ADVISORY FOR SNOW
AND BLOWING SNOW MONDAY NIGHT INTO TUESDAY. MODELS STILL HAVE JUST
ENOUGH DISAGREEMENT AND THE WORST CONDITIONS LOOK TO BE LATE THIRD
PERIOD INTO 4TH PERIOD SO WILL HOLD OFF ON ISSUING ANY HEADLINES BUT
IF THIS EVENINGS MODELS COME IN SIMILAR WILL LIKELY NEED SOMETHING.
MONDAY EVENING WILL START OFF RELATIVELY MILD IN THE SOUTHEAST WITH
TEMPERATURES ABOVE FREEZING SO A BETTER CHANCE FOR RAIN IN NORTHWEST
IOWA BEFORE MIDNIGHT BUT BY ABOUT 11PM TO MIDNIGHT SHOULD BE COLD
ENOUGH FOR SNOW. NO CONCERNS RIGHT NOW OF MIXED PRECIPITATION MONDAY
NIGHT AS THE WARM LAYER IS AT THE GROUND SO SHOULD BE EITHER RAIN OR
SNOW. WENT AHEAD AND INCREASED POPS TONIGHT INTO TUESDAY AND
INCREASED QPF AMOUNTS SOME SO THAT BY TUESDAY EVENING SO THAT MUCH
OF THE AREA SHOULD SEE 2 TO 4 INCHES WITH THE JAMES VALLEY WEST
SEEING THE BEST CHANCE AT APPROACHING 4 INCHES. AGAIN...WITH 2 TO 4
INCHES OF SNOW AND 20 TO 35 MPH WINDS ON TUESDAY AND TUESDAY NIGHT
HAZARDOUS TRAVEL IS LOOKING MORE LIKELY TUESDAY INTO WEDNESDAY.
BY WEDNESDAY EVERYTHING SHOULD BE TO THE EAST OF THE AREA AND WINDS
WILL DIMINISH THROUGH THE DAY. CLOUD COVER SHOULD ALSO BREAK UP A
BIT...AT LEAST GETTING DOWN TO MOSTLY CLOUDY. WITH FRESH SNOW ON THE
GROUND EXPECTING HIGHS MAINLY IN THE 20S.
IN THE OUTER PERIODS (THURSDAY THROUGH SUNDAY)...STILL AN
INTERESTING SYSTEM COMING THROUGH ON THURSDAY NIGHT INTO FRIDAY. THE
12Z GFS SEEMED A BIT OUT TO LUNCH BUT THE 12Z ECMWF AND THE 12Z
PARALLEL GFS BOTH AGREED WELL AND SHOWED SOME CONSISTENCY FROM
YESTERDAYS RUNS. UNFORTUNATELY THE SUPERBLEND IS POLLUTED WITH THE
12Z GFS SO POPS CAME IN MUCH LOWER. HAVING TROUBLE COLLABORATING
HIGHER POPS BUT RIGHT NOW ANTICIPATE THAT POPS WILL NEED TO BE
INCREASED FOR ESPECIALLY THURSDAY NIGHT. AFTER THIS STARTING TO LOOK
LIKE A PERIOD OF COLDER WEATHER WILL SETTLE IN AS A LARGE SCALE
TROUGH SETS UP NORTHERLY FLOW ALOFT INTO THE NORTHERN ROCKIES AND
NORTHERN PLAINS. SO ANTICIPATING HIGHS IN THE TEENS AND 20S FRIDAY
INTO SUNDAY WITH LOWS IN THE SINGLE DIGITS...POSSIBLY DIPPING BELOW
ZERO ASSUMING PARALLEL AND ECMWF ARE MORE ON TARGET. SO WENT AHEAD
AND DROPPED SUPERBLEND LOWS ABOUT 2 TO 4 DEGREES IN MOST LOCATIONS
SATURDAY MORNING AND SUNDAY MORNING.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 1147 PM CST SUN DEC 21 2014
LARGELY EXPECT IFR CIGS TO DOMINATE THROUGH THE PERIOD NEAR/EAST OF
THE JAMES RIVER...THOUGH WILL LIKELY SEE BRIEF IMPROVEMENT TO LOWER
END MVFR...AND/OR DETERIORATION TO LIFR AT TIMES. DID INCLUDE SOME
POTENTIAL TIMING FOR THESE CATEGORY CHANGES...THOUGH CONFIDENCE IS
ON THE LOW SIDE.
AREA OF LIGHT RAIN LIFTING NORTH INTO THE REGION AT THE START OF THE
PERIOD...WITH TEMPERATURES IN THE MID-UPPER 30S SO ICING WILL NOT BE
A FACTOR. MODELS HAVE TRENDED TOWARD A MID LEVEL DRY SLOT MOVING
INTO WESTERN/CENTRAL PORTIONS OF THE FORECAST AREA FOR MUCH OF THE
DAY MONDAY...LEADING TO VERY LIGHT...IF ANY...PRECIPITATION FOR A
LARGE PORTION OF THE TAF PERIOD. WHAT PRECIPITATION DOES FALL SHOULD
GRADUALLY TRANSITION FROM LIGHT RAIN/DRIZZLE TO LIGHT SNOW...BUT AT
THIS TIME ANTICIPATE MVFR VISIBILITY AT WORST.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...
SHORT TERM...CHENARD
LONG TERM...08
AVIATION...JH
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
701 PM CST TUE DEC 23 2014
.UPDATE...
UPDATED FOR 00Z AVIATION DISCUSSION BELOW...
&&
.PREV DISCUSSION... /ISSUED 303 PM CST TUE DEC 23 2014/
SKIES ARE CLOUDY WITH WIDESPREAD RAIN ACROSS THE MIDSOUTH.
OCCASIONAL LIGHTNING STRIKES HAVE BEEN NOTED ACROSS NORTH
MISSISSIPPI...BUT UNLIKE OUR NEIGHBORS TO THE SOUTH AND EAST IN
CENTRAL MISSISSIPPI AND CENTRAL ALABAMA...NO STORMS HAVE EVEN
APPROACHED SEVERE LIMITS IN THE MIDSOUTH. ADDITIONAL SHOWERS ARE
DEVELOPING UPSTREAM ACROSS CENTRAL AND SOUTHERN ARKANSAS...ADDING
CONFIDENCE THAT WE STILL HAVE A LONG WAY TO GO BEFORE ALL OF THE
RAINFALL IS OVER. IN FACT...ANOTHER 24 HOURS OF RAINFALL IS
POSSIBLE ACROSS PORTIONS OF THE MIDSOUTH. WE WILL LIKELY SEE OUR
HEAVIEST AND MOST WIDESPREAD RAINFALL TONIGHT...ALTHOUGH THE
POTENTIAL FOR THUNDERSTORMS SHOULD DIMINISH AFTER SUNSET. THESE
SHOWERS WILL FALL IN A MORE STABLE...COOLER AIRMASS BEHIND A COLD
FRONT THAT IS CURRENTLY MOVING INTO MIDDLE TENNESSEE AND
APPROACHING THE ALABAMA STATE LINE. DOPPLER RADAR ESTIMATES SOME
LOCALIZED PORTIONS OF NORTH MISSISSIPPI HAVE ALREADY RECEIVED UP
TO AN INCH OF RAIN...BUT MOST OF THE MIDSOUTH HAS SEEN ONE HALF OF
AN INCH OR LESS. OVER THE NEXT 24 HOURS OR SO UP TO ABOUT ANOTHER
INCH IS POSSIBLE AT ANY GIVEN LOCATION. NO STRONG OR SEVERE
THUNDERSTORMS ARE EXPECTED.
WE AREN`T GOING TO SEE A WHITE CHRISTMAS THIS YEAR. AS IS
TYPICAL...MOISTURE WILL BE QUICKLY EXITING THE MIDSOUTH CHRISTMAS
EVE NIGHT AS THE COOLER AIR MOVES IN CHRISTMAS MORNING. LOWS
CHRISTMAS MORNING SHOULD BE WITHIN A DEGREE OR TWO EITHER SIDE OF
FREEZING...COOL ENOUGH TO LIGHT THE FIREPLACE WHILE UNWRAPPING
GIFTS. A TRANSIENT...BROAD UPPER LEVEL RIDGE WILL SHIFT ACROSS
THE MIDSOUTH ON CHRISTMAS RESULTING IN 12-24 HOURS OF
SUNSHINE/CLEAR SKIES. HIGHS ON CHRISTMAS SHOULD CLIMB INTO THE
LOW 50S ACROSS MOST OF THE REGION.
CLOUDS AND A CHANCE OF RAIN WILL RETURN FRIDAY. A TROUGH WILL DIG
OVER THE FOUR CORNERS AREA AND A SURFACE LOW WILL DEVELOP ALONG
THE LEE SIDE OF THE ROCKIES NEAR THE OKLAHOMA PANHANDLE. THIS
WILL PUT THE MIDSOUTH UNDER SOUTHWEST FLOW. SOUTHERN STREAM ENERGY
WILL ENHANCE CLOUD COVER EARLY FRIDAY WITH RAIN RETURNING BY THE
AFTERNOON HOURS AS THE TROUGH BEGINS TO SHIFT INTO THE PLAINS.
NEXT WEEKEND LOOKS WET BUT THERE IS SOME UNCERTAINTY IN THE
MODELS. THE CURRENT FORECAST HAS ABOUT 5 CONSECUTIVE PERIODS...OR
60 HOURS...OF CHANCE OR HIGHER RAIN CHANCES. HOPEFULLY GUIDANCE
WILL CONVERGE ON A COMMON SOLUTION AND WE CAN NARROW THAT WINDOW
DOWN TO A MORE REALISTIC PERIOD OF TIME. THE GOOD NEWS IS THAT
NONE OF IT LOOKS TO BE OF THE FREEZING OR FROZEN VARIETY.
TEMPERATURES THROUGH THE PERIOD...SEASONAL ON CHRISTMAS
DAY...ABOVE NORMAL ON FRIDAY COOLING TO SLIGHTLY BELOW NORMAL
BEHIND THE FRONT SATURDAY. BELOW NORMAL SUNDAY THROUGH TUESDAY.
&&
.AVIATION...00Z TAF CYCLE
MAIN AREA OF RA/TSRA HAS PUSHED EAST/NORTHEAST OF ALL TERMINALS
SAVE TUP WHERE -RA SHOULD LAST FOR AN ADDITIONAL HOUR OR SO BEFORE
EXITING. GUIDANCE HAS CONTINUED TO BE INCONSISTENT WITH REGARD TO
CIGS THIS AFTERNOON AND OVERNIGHT...HOWEVER...IT APPEARS THAT MEM
SHOULD REMAIN ABOVE IFR CRITERIA WITH RELATIVELY DRY LOW LEVELS
DEPICTED IN BOTH RAP AND HRRR PROGS. HAVE MAINTAINED A 1400FT DECK
AFTER 04Z THROUGH THE OVERNIGHT HOURS WITH A LOWERING TO NEAR
1000 FT TOWARD 11Z AS LOW LEVEL COLD ADVECTION BECOMES STRONGER. A
DEFORMATION BAND LOOKS TO DEVELOP ACROSS THE MS RIVER VALLEY AFTER
03Z WHICH WILL BRING ANOTHER PERIOD OF -RA/SHRA TO ALL TERMINALS
THROUGH 18-21Z WEDNESDAY.
AFTER THE SYSTEM EXITS...A SLOW LIFTING OF CEILINGS SHOULD BEGIN
AT ALL TERMINALS BY 00Z THURSDAY.
TVT
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1222 PM CST MON DEC 22 2014
.AVIATION...
MOST OF THE LOW CLOUDS HAVE ERODED DUE TO THE DOWNSLOPING WESTERLY
COMPONENT IN THE LOWER AND MID LEVELS. WE CONTINUE TO SEE SOME IFR
DECKS AT DRT BUT SHOULD SEE THIS DISSIPATE IN THE NEXT HOUR OR SO.
HIGH LEVEL CLOUDINESS WILL PERSIST THIS AFTERNOON ACROSS ALL THE
AREA. WINDS WILL VEER TO A WESTERLY DIRECTION BY LATE AFTERNOON
WITH EVEN SOME LIGHT NORTHERLY WINDS POSSIBLE BY LATE EVENING.
NAM MODEL IS VERY BULLISH IN BRINGING A REPEAT OF IFR INTO
SAT/SSF IN THE MORNING BEFORE THE BIG FRONTAL PUSH. HRRR IS ALSO
STARTING TO HIT THIS SCENARIO. THEY ARE BANKING ON THE WESTERLY
FLOW DYING OFF THIS EVENING AND A RETURN OF SE WINDS BEFORE THE
FRONT ARRIVES.
THE TRUE COLD FRONT WITH COLDER AIR AND STRONGER SPEEDS WILL WAIT
UNTIL TUE MORNING. ALONG WITH THE COLD AIR ADVECTION...MODELS ARE
DEVELOPING SOME OVERUNNING CLOUDS BELOW 850 MB. WILL BRING DECKS
DOWN TO MVFR AT ALL SITES BY 16Z TOMORROW. WE WILL LIKELY HAVE
SOME SORT OF LIGHT PRECIPITATION AT AUSTIN IN THE MORNING BUT AM
NOT CONFIDENT ENOUGH WITH TIMING AND OVERALL POP CHANCES TO INPUT
AT THIS TIME. WILL WATCH LATER RUNS TO SEE IF THIS TREND
CONTINUES. N AND NW WINDS WILL BE RATHER GUSTY OVER 20 KTS TUE
AFTERNOON ESPECIALLY ALONG THE ESCARPMENT.
&&
.PREV DISCUSSION... /ISSUED 917 AM CST MON DEC 22 2014/
UPDATE...
WITH SOME LOCATIONS ON THE PLATEAU STILL REPORTING FOGGY
CONDITIONS AT 15Z. EXTENDED PATCHY FOG MENTION FOR THESE LOCATIONS
ANOTHER FEW HOURS. ALSO RAN STANDARD UPDATE FOR HOURLY T TRENDS
AND DEW T. OTHERWISE...FORECAST ON TRACK.
PREV DISCUSSION... /ISSUED 600 AM CST MON DEC 22 2014/
AVIATION...
STRONG SOUTHEASTERLY FLOW ABOVE THE SURFACE HAS RESULTED IN
IFR/LIFR CIGS THIS MORNING. ALSO SEEING VIS REDUCED IN FOG WITH
THE WORST VIS AT DRT. CONDITIONS SHOULD IMPROVE BY AROUND NOON AS
WEST WINDS MOVE IN. A COLD FRONT WILL MOVE THROUGH THE REGION
TUESDAY BRINGING NORTH WINDS BY MID-MORNING.
PREV DISCUSSION... /ISSUED 408 AM CST MON DEC 22 2014/
SHORT TERM (TODAY THROUGH TUESDAY)...
FOG COVERS MOST OF SOUTH CENTRAL TEXAS EARLY THIS MORNING. A
DEEPENING TROUGH MOVING OUT INTO THE PLAINS WILL CAUSE SOUTHWEST
TO WESTERLY LOWER LEVEL WINDS. LOW CLOUDS AND FOG ERODE FROM WEST
TO EAST BY MID MORNING ALLOWING TEMPERATURES TO RISE TO WELL ABOVE
AVERAGE THIS AFTERNOON. A PRE-FRONTAL TROUGH MOVES ACROSS OUR AREA
TONIGHT...THEN A COLD FRONT EARLY TUESDAY WITH AN UPPER LEVEL
TROUGH LATE TUESDAY. THE FRONT AND UPPER TROUGH GENERATE UPWARD
MOTION OF SUFFICIENT MOISTURE TO PRODUCE SLIGHT CHANCE TO CHANCE
POPS FOR SHOWERS NORTHEAST OF A ROCKSPRINGS TO NEW BRAUNFELS TO
KARNES CITY LINE. RAINFALL WILL BE LIGHT WITH AMOUNTS LESS THAN
ONE QUARTER INCH. COLD ADVECTION AND CLOUD COVER WILL DROP
TEMPERATURES TO BELOW AVERAGE ON TUESDAY. BREEZY CONDITIONS WILL
DEVELOP IN THE WAKE OF THE FRONTAL PASSAGE DUE TO TIGHT PRESSURE
GRADIENT.
LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...
THE BREEZY CONDITIONS CONTINUE INTO TUESDAY NIGHT KEEPING THE
TEMPERATURES FROM BOTTOMING OUT...ONLY FLIRTING WITH THE FREEZING
MARK IN SOME LOW LYING AND WIND SHELTERED HILL COUNTRY SPOTS
WEDNESDAY MORNING. BELOW AVERAGE TEMPERATURES CONTINUE CHRISTMAS
EVE THROUGH CHRISTMAS MORNING. MORE WIDESPREAD FREEZING
TEMPERATURES ARE EXPECTED CHRISTMAS MORNING AS THE SURFACE HIGH
SETTLES OVER THE AREA...BUT STILL MAINLY IN LOW LYING SPOTS IN
THE HILL COUNTRY AND ALONG THE ESCARPMENT. THE SURFACE HIGH MOVES
OFF TO THE EAST ALLOWING A SOUTHERLY FLOW AND TEMPERATURES WARMING
TO ABOVE AVERAGE FOR CHRISTMAS AFTERNOON. A ZONAL FLOW ALOFT
PREVAILS FRIDAY THROUGH SUNDAY WITH THE MODELS DELAYING THE NEXT
STRONG COLD FRONT UNTIL FRIDAY NIGHT INTO EARLY SATURDAY. HAVE
WARMED FRIDAY AFTERNOON TEMPERATURES ONLY SLIGHTLY. SOME MODELS
ARE SHOWING RAIN CHANCES. HOWEVER...MOISTURE WILL BE LIMITED AND
HAVE NOT INCLUDED POPS. BELOW AVERAGE TEMPERATURES ARE EXPECTED
SATURDAY AND SUNDAY WHICH WILL LIKELY CONTINUE BEYOND THIS
FORECAST THROUGH THE NEW YEAR.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 73 49 56 38 56 / 0 10 30 - 0
AUSTIN BERGSTROM INTL AIRPORT 72 47 57 37 56 / 0 10 20 - 0
NEW BRAUNFELS MUNI AIRPORT 74 49 58 38 57 / 0 10 10 - 0
BURNET MUNI AIRPORT 71 46 54 36 53 / - 10 30 0 0
DEL RIO INTL AIRPORT 75 48 59 37 59 / 0 - - 0 0
GEORGETOWN MUNI AIRPORT 70 47 55 36 54 / 0 10 30 - 0
HONDO MUNI AIRPORT 75 46 61 35 59 / 0 - 10 0 0
SAN MARCOS MUNI AIRPORT 72 48 57 36 56 / 0 10 20 - 0
LA GRANGE - FAYETTE REGIONAL 73 52 57 38 56 / - 10 30 - 0
SAN ANTONIO INTL AIRPORT 75 50 59 38 58 / 0 - 10 - 0
STINSON MUNI AIRPORT 75 50 59 38 59 / 0 - 10 - 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...09
SYNOPTIC/GRIDS...29
PUBLIC SERVICE/DATA COLLECTION...33
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1155 PM CST SUN DEC 21 2014
.UPDATE...06Z AVIATION BELOW.
&&
.AVIATION...AT 05Z IFR CEILINGS PREVAILED ALONG AND SOUTHWEST OF
A ERV-SAT-VCT LINE. EXCEPTION WAS SKC OUT AT DRT...BUT THIS
SHOULD FILL IN OVER THE NEXT HOUR OR TWO. NORTHEAST OF THIS LINE
MVFR CEILINGS PREVAILED. SHALLOW MOISTURE WILL REMAIN TRAPPED
BENEATH INVERSION OVERNIGHT...WITH SATURATION AND CLOUD DECK
LOWERING EARLY IN THE MORNING. LOOKING MORE LIKELY FOR MIX OF
IFR/LIFR CONDITIONS ACROSS SOUTHERN AND WESTERN AREAS...AND
CONTINUED TO INDICATE THIS AT SAT/SSF/DRT. IN ADDITION...PATCHY
-DZ OCCURING OVERNIGHT ALONG THE I-35 CORRIDOR. WESTERLY LOW
LEVEL FLOW WILL DEVELOP ALONG THE I-35 CORRIDOR 15Z-18Z WITH
PASSAGE OF LOW LEVEL TROUGH...WITH NORTHWEST FLOW OVER THE RIO
GRANDE AND HILL COUNTRY. THIS SHOULD RESULT IN BETTER MIXING AND
CLEARING ALONG AND WEST OF I-35 MID TO LATE MORNING...AND
EVENTUALLY VFR CONDITIONS AT ALL TAF SITES.
&&
.PREV DISCUSSION... /ISSUED 1131 PM CST SUN DEC 21 2014/
UPDATE...
UPDATED TO INCLUDE DRIZZLE MENTION THROUGH 09Z FOR I35 CORRIDOR
AND EAST DUE TO LATEST OBS. FOG IS BEGINNING TO SET IN ALONG THE
SOUTHERN RIO GRANDE VALLEY AND UP TO THE SOUTHERN PERIPHERY OF THE
ESCARPMENT. THIS IS ON TRACK WITH THE EVOLUTION DEPICTED IN THE
MODELS SO CONFIDENCE HAS INCREASED IN THE CURRENT FORECAST.
HIGH CLOUDS ARE MOVING IN FROM THE NORTHWEST IN ADDITION TO THE
LOW CEILING DEVELOPMENT SPREADING BACK WEST TOWARDS KDRT. SEEING
WINDS JUST NORTH OF THE CWA AT 15-20 MPH SUSTAINED WITH GUSTS UP
TO 25 MPH IN RESPONSE TO A TIGHTENING PRESSURE GRADIENT. FOR
NOW...THE FORECAST STILL LOOKS PRETTY GOOD FOR THE WINDS BUT IF
THEY CONTINUE TO INCREASE...MAY NEED TO UPDATE AGAIN TO ACCOUNT
FOR THIS.
TB3
PREV DISCUSSION... /ISSUED 737 PM CST SUN DEC 21 2014/
UPDATE...
LATEST IR SATELLITE SHOWS LOW LEVEL CLOUD DECK DETERIORATING WEST
OF I35 CORRIDOR. KDRT SHOWING SOME LIGHT FOG ALREADY AT 01Z.
BOTH RUC AND HRRR INDICATE ZERO DEGREE DEWPOINT DEPRESSIONS ALONG
THE RIO GRANDE UP TO KDRT AND UP ONTO THE ESCARPMENT BEGINNING
AROUND 06Z. WITH A TIGHTENING SFC GRADIENT OVER OUR WEST AND
RESULTANT WINDS IN THE 10-15 MPH RANGE ALREADY...DONT THINK FOG
WILL BE ABLE TO SET IN ON THE ESCARPMENT MUCH...HOWEVER INCLUDED
AREAS OF FOG ALONG THE RIO GRANDE VALLEY AND SOUTH OF THE
ESCARPMENT BY 09Z. ALSO UPDATED SKY GRIDS...HOURLY T...AND HOURLY
DEW T GRIDS TO CAPTURE LATEST TRENDS.
PREV DISCUSSION... /ISSUED 339 PM CST SUN DEC 21 2014/
SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
CLEARING HAS BEEN VERY STUBBORN THIS AFTERNOON BUT AREAS OUT WEST
AND SOUTHWEST ARE FINALLY STARTING TO SHOW SOME SUNSHINE. UPPER
TROF AXIS IS OVER THE STATE RIGHT NOW WITH MORE CLOUDINESS AND
MOISTURE UPSTREAM OVER THE ROCKIES. MOST AREAS WILL CLOUD BACK UP
OVERNIGHT AND HAVE MENTIONED SOME PATCHY FOG OVER SOUTHERN AREAS.
AREAS THAT CLEAR THIS EVENING WILL HAVE A BETTER CHANCE OF GETTING
THE FOG. LOW AND MID LEVEL WIND FIELDS WILL HAVE A WESTERLY
COMPONENT ON MONDAY MEANING WARMER TEMPERATURES AND MORE SUNSHINE.
MOST AREAS SHOULD REACH INTO THE 70S. SHOULD BE A VERY PLEASANT
DAY. ALTHOUGH WE LOSE THE LOW CLOUDS TOMORROW NIGHT WE WILL STILL
HAVE SOME MID AND HIGH CLOUDS AROUND WITH THE UPSTREAM SYSTEM OVER
THE ROCKIES. LOWS MONDAY NIGHT EXPECTED TO BE IN THE 40S TO LOW
50S.
LONG TERM (TUESDAY THROUGH SUNDAY)...
WILL SEE A COLD FRONT PUSH THROUGH THE CWA EARLY TUE MORNING WHILE A
DEEP TROF DEVELOPS OVER THE CENTRAL AND SOUTHERN PLAINS. AN UPPER
WAVE WILL PUSH SE OUT OF THE ROCKIES ON TUE WITH SOME OF ITS
ENERGY STAYING OVER SOUTH CENTRAL TEXAS EARLY WED. WITH THE COLD
FRONT AND UPPER LEVEL TROFFING...LOOKS LIKE TUE WILL BE MOSTLY
CLOUDY AND COOLER. 700 MB TROF AXIS SHIFTS EAST LATE TUE NIGHT
WHICH SHOULD MEAN A CLEARING PATTERN ON WED ALTHOUGH TEMPS WILL
REMAIN COOL AS THE SURFACE HIGH REMAINS OVER WEST TEXAS AND THE
ROCKIES. THE UPPER PATTERN FLATTENS AS TEXAS IS AT THE BASE OF A
LONG WAVE TROFFING PATTERN ACROSS MOST OF THE COUNTRY BY MID WEEK.
MOISTURE LEVELS WILL REMAIN LOW FOR THU AND FRI WHICH WILL
TRANSLATE TO MOSTLY SUNNY SKIES...COOL/COLD NIGHTS...AND COOL
AFTERNOON HIGHS IN THE 60S. WILL SEE A RETURN OF MORNING LOWS IN
THE 30S MIDDLE TO THE END OF THE WEEK. ANOTHER COLD FRONT IS
FORECAST FOR FRIDAY BUT SHOULD COME THROUGH DRY AS THERE WILL BE
LITTLE TO NO MOISTURE TO WORK WITH.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 52 71 48 57 38 / 10 - 10 20 -
AUSTIN BERGSTROM INTL AIRPORT 51 71 47 57 37 / 10 - 10 20 -
NEW BRAUNFELS MUNI AIRPORT 50 72 49 58 38 / 10 - 10 10 -
BURNET MUNI AIRPORT 48 70 45 54 36 / 10 - 10 20 -
DEL RIO INTL AIRPORT 43 75 48 59 37 / 10 - 10 10 -
GEORGETOWN MUNI AIRPORT 50 70 46 55 36 / 10 - 10 20 -
HONDO MUNI AIRPORT 48 73 46 61 34 / 10 - 10 10 -
SAN MARCOS MUNI AIRPORT 51 72 47 57 36 / 10 - 10 10 -
LA GRANGE - FAYETTE REGIONAL 52 72 51 56 39 / 10 - 10 20 -
SAN ANTONIO INTL AIRPORT 52 73 49 59 38 / 10 - 10 10 -
STINSON MUNI AIRPORT 51 72 50 60 38 / 10 - 10 10 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...76
SYNOPTIC/GRIDS...03
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1131 PM CST SUN DEC 21 2014
.UPDATE...
UPDATED TO INCLUDE DRIZZLE MENTION THROUGH 09Z FOR I35 CORRIDOR
AND EAST DUE TO LATEST OBS. FOG IS BEGINNING TO SET IN ALONG THE
SOUTHERN RIO GRANDE VALLEY AND UP TO THE SOUTHERN PERIPHERY OF THE
ESCARPMENT. THIS IS ON TRACK WITH THE EVOLUTION DEPICTED IN THE
MODELS SO CONFIDENCE HAS INCREASED IN THE CURRENT FORECAST.
HIGH CLOUDS ARE MOVING IN FROM THE NORTHWEST IN ADDITION TO THE
LOW CEILING DEVELOPMENT SPREADING BACK WEST TOWARDS KDRT. SEEING
WINDS JUST NORTH OF THE CWA AT 15-20 MPH SUSTAINED WITH GUSTS UP
TO 25 MPH IN RESPONSE TO A TIGHTENING PRESSURE GRADIENT. FOR
NOW...THE FORECAST STILL LOOKS PRETTY GOOD FOR THE WINDS BUT IF
THEY CONTINUE TO INCREASE...MAY NEED TO UPDATE AGAIN TO ACCOUNT
FOR THIS.
TB3
&&
.PREV DISCUSSION... /ISSUED 737 PM CST SUN DEC 21 2014/
UPDATE...
LATEST IR SATELLITE SHOWS LOW LEVEL CLOUD DECK DETERIORATING WEST
OF I35 CORRIDOR. KDRT SHOWING SOME LIGHT FOG ALREADY AT 01Z.
BOTH RUC AND HRRR INDICATE ZERO DEGREE DEWPOINT DEPRESSIONS ALONG
THE RIO GRANDE UP TO KDRT AND UP ONTO THE ESCARPMENT BEGINNING
AROUND 06Z. WITH A TIGHTENING SFC GRADIENT OVER OUR WEST AND
RESULTANT WINDS IN THE 10-15 MPH RANGE ALREADY...DONT THINK FOG
WILL BE ABLE TO SET IN ON THE ESCARPMENT MUCH...HOWEVER INCLUDED
AREAS OF FOG ALONG THE RIO GRANDE VALLEY AND SOUTH OF THE
ESCARPMENT BY 09Z. ALSO UPDATED SKY GRIDS...HOURLY T...AND HOURLY
DEW T GRIDS TO CAPTURE LATEST TRENDS.
PREV DISCUSSION... /ISSUED 630 PM CST SUN DEC 21 2014/
UPDATE...00Z AVIATION BELOW.
AVIATION...CLEARING HAS OCCURRED LATE THIS AFTERNOON AND EARLY
EVENING ALONG THE RIO GRANDE...WITH VFR CONDITIONS NOW AT DRT.
AT 00Z OVC MVFR STRATUS DECK STRETCHES FROM JUST NORTH OF DRT TO
SAT/SSF/AUS THEN ENCOMPASSES MOST AREAS ALONG AND EAST OF I-35
ACROSS SOUTH-CENTRAL TEXAS. SHALLOW MOISTURE TRAPPED BENEATH
INVERSION WILL CONTINUE OVERNIGHT...WITH SATURATION AND CLOUD DECK
LOWERING AFTER 06Z. HAVE INDICATED IFR CONDITIONS DEVELOPING
FIRST AT SAT/SSF AFTER 06Z AND LATER AT AUS AFTER 09Z. FORECAST
SOUNDINGS AND MOS INDICATE THERE COULD BE LIFR CEILINGS AND IFR
VISIBILITY DEVELOPING ALONG THE I-35 CORRIDOR TOWARDS DAYBREAK.
FARTHER WEST...HAVE INDICATED IFR CEILINGS DEVELOPING BACK TOWARDS
DRT AROUND 12Z...ALTHOUGH CONFIDENCE IS LOWER. SOUTHWEST AND
WESTERLY LOW LEVEL FLOW SHOULD PROMOTE BETTER MIXING AND CLEARING
ALONG AND WEST OF I-35 LATE MONDAY MORNING INTO THE EARLY
AFTERNOON.
PREV DISCUSSION... /ISSUED 339 PM CST SUN DEC 21 2014/
SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
CLEARING HAS BEEN VERY STUBBORN THIS AFTERNOON BUT AREAS OUT WEST
AND SOUTHWEST ARE FINALLY STARTING TO SHOW SOME SUNSHINE. UPPER
TROF AXIS IS OVER THE STATE RIGHT NOW WITH MORE CLOUDINESS AND
MOISTURE UPSTREAM OVER THE ROCKIES. MOST AREAS WILL CLOUD BACK UP
OVERNIGHT AND HAVE MENTIONED SOME PATCHY FOG OVER SOUTHERN AREAS.
AREAS THAT CLEAR THIS EVENING WILL HAVE A BETTER CHANCE OF GETTING
THE FOG. LOW AND MID LEVEL WIND FIELDS WILL HAVE A WESTERLY
COMPONENT ON MONDAY MEANING WARMER TEMPERATURES AND MORE SUNSHINE.
MOST AREAS SHOULD REACH INTO THE 70S. SHOULD BE A VERY PLEASANT
DAY. ALTHOUGH WE LOSE THE LOW CLOUDS TOMORROW NIGHT WE WILL STILL
HAVE SOME MID AND HIGH CLOUDS AROUND WITH THE UPSTREAM SYSTEM OVER
THE ROCKIES. LOWS MONDAY NIGHT EXPECTED TO BE IN THE 40S TO LOW
50S.
LONG TERM (TUESDAY THROUGH SUNDAY)...
WILL SEE A COLD FRONT PUSH THROUGH THE CWA EARLY TUE MORNING WHILE A
DEEP TROF DEVELOPS OVER THE CENTRAL AND SOUTHERN PLAINS. AN UPPER
WAVE WILL PUSH SE OUT OF THE ROCKIES ON TUE WITH SOME OF ITS
ENERGY STAYING OVER SOUTH CENTRAL TEXAS EARLY WED. WITH THE COLD
FRONT AND UPPER LEVEL TROFFING...LOOKS LIKE TUE WILL BE MOSTLY
CLOUDY AND COOLER. 700 MB TROF AXIS SHIFTS EAST LATE TUE NIGHT
WHICH SHOULD MEAN A CLEARING PATTERN ON WED ALTHOUGH TEMPS WILL
REMAIN COOL AS THE SURFACE HIGH REMAINS OVER WEST TEXAS AND THE
ROCKIES. THE UPPER PATTERN FLATTENS AS TEXAS IS AT THE BASE OF A
LONG WAVE TROFFING PATTERN ACROSS MOST OF THE COUNTRY BY MID WEEK.
MOISTURE LEVELS WILL REMAIN LOW FOR THU AND FRI WHICH WILL
TRANSLATE TO MOSTLY SUNNY SKIES...COOL/COLD NIGHTS...AND COOL
AFTERNOON HIGHS IN THE 60S. WILL SEE A RETURN OF MORNING LOWS IN
THE 30S MIDDLE TO THE END OF THE WEEK. ANOTHER COLD FRONT IS
FORECAST FOR FRIDAY BUT SHOULD COME THROUGH DRY AS THERE WILL BE
LITTLE TO NO MOISTURE TO WORK WITH.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 52 71 48 57 38 / 10 - 10 20 -
AUSTIN BERGSTROM INTL AIRPORT 51 71 47 57 37 / 10 - 10 20 -
NEW BRAUNFELS MUNI AIRPORT 50 72 49 58 38 / 10 - 10 10 -
BURNET MUNI AIRPORT 48 70 45 54 36 / 10 - 10 20 -
DEL RIO INTL AIRPORT 43 75 48 59 37 / 10 - 10 10 -
GEORGETOWN MUNI AIRPORT 50 70 46 55 36 / 10 - 10 20 -
HONDO MUNI AIRPORT 48 73 46 61 34 / 10 - 10 10 -
SAN MARCOS MUNI AIRPORT 51 72 47 57 36 / 10 - 10 10 -
LA GRANGE - FAYETTE REGIONAL 52 72 51 56 39 / 10 - 10 20 -
SAN ANTONIO INTL AIRPORT 52 73 49 59 38 / 10 - 10 10 -
STINSON MUNI AIRPORT 51 72 50 60 38 / 10 - 10 10 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...76
SYNOPTIC/GRIDS...03
PUBLIC SERVICE/DATA COLLECTION...12
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
901 PM CST TUE DEC 23 2014
NEW INFORMATION ADDED TO UPDATE SECTION
.UPDATE...
ISSUED AT 840 PM CST TUE DEC 23 2014
JUST SOME LINGERING LGT PCPN ACRS THE FCST AREA EARLY THIS
EVENING. KGRB 88D STILL HAD AN AREA OF RETURNS LIFG NEWD TO THE W
OF THE FOX VALLEY...PROBABLY JUST SOME SPRINKLES. OTHERWISE...SFC
OBS INDICATED MAINLY PATCHY DZ/FZDZ...WITH SOME FLURRIES IN THE N.
MODEL FCST SOUNDINGS SHOW MID-LVL DRY AIR TO REMAIN IN PLACE
THROUGH THE NGT AND INTO TOMORROW MORNING...SUGGESTING JUST
DZ/FZDZ AS PCPN TYPE. BUT CARRIED FLURRIES IN THE FCST FOR N-C
ANYWAY AS STLT HAS A LITTLE COLDER CLD TOPS THERE.
A SMALL PORTION OF THE FCST AREA FM ABOUT MFI/ISW ENEWD TOWARD
WAUSAUKEE HAS PRETTY GOOD CONDITIONS FOR FOG THIS EVENING. THAT
AREA GOT ENOUGH SNOW IN THE PAST 24 HRS TO HAVE SNOW-COVERED
GROUND. WINDS IN THAT AREA ARE LGT AS THAT IS ALONG THE TRACK OF
ELONGATED AREA OF SFC LOW PRESSURE DRIFTING SLOWLY NEWD ACRS THE
AREA. IT/S ALSO AN AREA WHERE SFC DWPTS HAVE CREPT AOA FZG. PLAN
TO CONT TO HANDLE WITH AN SPS...AND WL LIKELY RE-ISSUE THE CURRENT
SPS TO COVER THE SITN INTO THE EARLY MORNING HOURS.
FINALLY...STILL KEENLY WATCHING HOW THE LATEST GUIDANCE IS
HANDLING THE SECONDARY CYCLONE THAT WL LIFT NWD ALONG THE
BAROCLINIC ZONE IN THE NEXT 24-36 HRS. THE NAM HAS SEEMINGLY
SETTLED IN ON A TRACK THAT KEEPS THE PCPN JUST TO OUR E. HAVE ALSO
BEEN WATCHING THE ENDING OF THE HOURLY RAP RUNS...AND THE PAST FEW
OF THOSE GRAZED THE LAKESHORE TOMORROW AFTN/EVENING...AND EVEN
BROUGHT PCPN BACK INTO THE ERN FOX VALLEY AT TIMES.
THE REAL PROBLEM WE/VE HAD DEALING WITH THIS SYSTEM ACTUALLY
ISN/T SO MUCH THE TRACK OF THE CYCLONE. THAT HAS CERTAINLY BEEN
CHAOTIC ON THE NUMERICAL GUIDANCE...BUT WITH A TYPICAL
CYCLONE...THE ENVELOPE OF SOLUTIONS OUT THERE NOW WOULD ALLOW FOR
DECENT CONFIDENCE IN POPS AND A BALLPARK ESTIMATE OF
PCPN/SNOW. THE REAL PROBLEM HAS BEEN THE VERY NARROW/COMPRESSED
DEFORMATION ZONE ON THE WRN FLANK OF THE CYCLONE. THAT SEEMS TO BE
THE RESULT OF HAVING A FAIRLY SMALL CYCLONE...AND THE INTERACTION
OF THE CYCLONE WITH UPSTREAM ENERGY DRIVING EWD ACRS THE NRN
PLAINS. THAT ENERGY WL IMPINGE ON THE DEFORMATION ZONE ON THE WRN
FLANK OF THE CYCLONE...SO THE WIDTH OF THE PCPN W OF THE STORM
CENTER IS UNUSUALLY NARROW. IN ANY CASE...CURRENT FCST SEEMS TO
HAVE THINGS HANDLED FAIRLY WELL...WITH CHC POPS ERN FOX VALLEY AND
SOME LIKELY POPS RIGHT AT THE LAKESHORE. NO SIG CHGS TO THAT THIS
EVENING.
UPDATED GRIDS SENT ABOUT 1/2 HR AGO.
UPDATE
ISSUED AT 526 PM CST TUE DEC 23 2014
UST LGT PCPN LINGERING ACRS N-C WI...SO WL ALLOW THE ADVISORY TO
EXPIRE AT 6 PM AS SCHEDULED.
&&
.SHORT TERM...TONIGHT AND WEDNESDAY
ISSUED AT 237 PM CST TUE DEC 23 2014
MAIN FCST CONCERNS DEAL WITH THE DEMISE OF ONE SYSTEM AND ITS
ASSOCIATED SNOW TNGT AND THEN TRYING TO FIGURE OUT THE PATH OF THE
NEXT SYSTEM TOWARD THE GREAT LAKES ON WED.
THE 20Z MSAS SFC ANALYSIS SHOWED A WEAKENING AREA OF LOW PRES OVER
CNTRL WI MOVING ALONG A QUASI-STNRY BOUNDARY. THIS BOUNDARY WAS
SEPARATING WARM...MOIST AIR ON SOUTH WINDS OVER ERN WI FROM COOL...
MOIST AIR OVER WRN WI ON NORTH WINDS. RADAR MOSAIC CONTINUED TO
SHOW PCPN PIVOTING AROUND THE SFC LOW WITH MAINLY LIGHT RAIN OR
DRIZZLE OVER ERN WI AND EITHER LIGHT SNOW OR A RAIN/SNOW MIX OVER
CNTRL WI. PLAN ON CANCELING THE WINTER WX ADVY FOR ALL BUT VILAS/
ONEIDA COUNTIES WHERE SNOW INTENSITY IS LIGHT OR MIXED PCPN HAS
TAKEN OVER.
SYSTEM OVER THE GREAT LAKES REGION WL CONT TO DRIFT NE AND
STEADILY WEAKEN TNGT AS MAIN ENERGY SHIFTS TOWARD THE TN/OHIO
RIVER VALLEYS WHERE A STRENGTHENING SFC LOW TO RESIDE. FCST
SOUNDINGS INDICATE A LOSS OF MID-LEVEL SATURATION WHICH WOULD
DIMINISH ANY PCPN MAINLY TO EITHER FREEZING DRIZZLE OR DRIZZLE
DEPENDING ON SFC TEMPS. LOW-LEVELS OF THE ATMOSPHERE REMAIN
MOIST...SO PATCHY FOG TO BE A GOOD BET. ANOTHER MILD NGT ON TAP
ACROSS THE FCST AREA WITH MIN TEMPS ONLY RANGING FROM AROUND 30
DEGS N-CNTRL TO THE LWR TO MID 30S NEAR LAKE MI.
EVEN AT THIS LATE DATE...THE MODELS CONT TO STRUGGLE WITH THE
MOVEMENT OF THIS SFC LOW AS IT LIFTS N-NE INTO THE GREAT LAKES ON
WED. AN ERN TRACK (TOWARD DETROIT) PER ECMWF/GEM WOULD ESSENTIALLY
KEEP ANY SNOW POTENTIAL TO OUR EAST AND LEAVE NE WI CLOUDY WITH
ONLY A MINIMAL CHC OF ANY PCPN. A WRN TRACK (TOWARD CNTRL SECTIONS
OF LWR MI) PER NAM/GFS WOULD BRING THE THREAT OF MEASURABLE SNOW
TO ERN WI. THE FINAL SOLUTION MAY NOT BE KNOWN UNTIL THE SFC LOW
ACTUALLY DEVELOPS OVER THE OZARKS AND MAKES IT MOVE TO THE N-NE.
FOR NOW...HAVE SPLIT THE MODEL DIFFERENCE WHICH BRINGS A GLANCING
BLOW TO FAR ERN WI WED AFTERNOON...BUT HAVE KEPT ANY SNOW
ACCUMULATIONS TO LESS THAN AN INCH. ANYONE WITH TRAVEL PLANS
TOWARD SE WI OR NRN IL WL WANT TO CHECK THE LATEST FCSTS AS TRAVEL
MAY BECOME QUITE MESSY DOWN THAT WAY. MAX TEMPS FOR WED WL RANGE
FROM THE LWR 30S OVER N-CNTRL WI TO THE MID 30S ACROSS ERN WI.
.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
ISSUED AT 237 PM CST TUE DEC 23 2014
PROGS CONTINUE TO HINT OF SOME PRECIPITATION BRUSHING OVER FAR
EASTERN WISCONSIN WEDNESDAY EVENING UNTIL THE UPPER LOW SYSTEM
SHIFTS EASTWARD. AFTER A PERIOD OF BLUSTERY NORTHWEST WINDS
WEDNESDAY EVENING...DIMINISHING WINDS EXPECTED OVERNIGHT AS A WEAK
RIDGE OF HIGH PRESSURE WORKS INTO THE AREA.
XMAS DAY EXPECTED TO BE QUIET...THEN LIGHT SNOW WILL BE ON THE
INCREASE LATE IN THE WEEK AS A TROUGH OF LOW PRESSURE AND MID
LEVEL SHORT WAVE SLIDE OVER THE MID SECTION OF THE COUNTRY. PROGS
SUGGEST THE LIGHT SNOW APPEARS TO BE FOCUSED IN THE TRAILING
BAROCLINIC PORTION FROM NORTHWEST WISCONSIN LATE THURSDAY NIGHT
INTO FRIDAY BEFORE TROUGH PASSAGE FRIDAY AFTERNOON INTO EVENING.
FORECAST TEMPS SUGGEST A VERY LIGHT MIX POSSIBLE OVER EAST CENTRAL
WISCONSIN FRIDAY AFTERNOON.
THE QUIET ZONAL FLOW WITH SLIGHTLY COOLER THAN NORMAL TEMPERATURES
WILL CONTINUE INTO THE WEEKEND. MEDIUM RANGE MODELS ARE NOT
INDICATING MUCH SNOW WITH A SHORT WAVE DROPPING INTO THE GREAT
LAKES REGION WHICH DEEPENS THE TROUGH OVER THE REGION EARLY NEXT
WEEK. THERE IS SOME AGREEMENT WITH AN ARCTIC SURGE OF AIR BY THE
MIDDLE OF NEXT WEEK AND USUALLY A CLIPPER TYPE SYSTEM PRECEDES
THIS BUT SO FAR NO INDICATION. AVAILABLE PROGS SUGGESTS SOME
SLIGHT MODERATION IN TEMPS LATE NEXT WEEK.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 526 PM CST TUE DEC 23 2014
PLENTY OF LINGERING LOW-LEVEL MOISTURE WL REMAIN IN THE WAKE OF
THE RAINS/SNOWS OF THE PAST 24 HRS. CORRIDOR ACRS CENTRAL WI NR
SFC LOW WL HAVE LGT WINDS AND MOISTURE OVER THE SNOW THAT FELL
LAST NGT/THIS MORNING...AND MAY HAVE SOME DENSE FOG THIS EVENING.
THAT CORRIDOR SHOULD FALL MAINLY BTWN THE C AND E-C WI TAF
SITES...BUT COULD CREEP BACK INTO CWA/AUW SO WL CARRY SOME LOW
VSBYS THERE. OTHERWISE...MORE SIG IMPROVEMENT IN CONDITIONS WL
HAVE TO WAIT UNTIL TOMORROW WHEN NLY FLOW STRENGTHENS ON THE WRN
FLANK OF CYCLONE LFTG TOWARD LAKE HURON.
&&
.HYDROLOGY...
ISSUED AT 237 PM CST TUE DEC 23 2014
MILD CONDITIONS OVER NORTHEAST WISCONSIN THROUGH WEDNESDAY ALONG
WITH RAINFALL AMOUNTS OF 0.25 TO 0.75 INCHES THROUGH TUESDAY
AFTERNOON MAY AFFECT ICE CONDITIONS ON AREA RIVERS AND LAKES.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE.........SKOWRONSKI
SHORT TERM.....KALLAS
LONG TERM......TDH
AVIATION.......SKOWRONSKI
HYDROLOGY......TDH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
520 PM CST TUE DEC 23 2014
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 202 PM CST TUE DEC 23 2014
FORECAST CHALLENGES INCLUDE LINGERING LIGHT PRECIPITATION TONIGHT
INTO WEDNESDAY AND THEN LOW-END PRECIPITATION CHANCES AGAIN
FRIDAY/FRIDAY NIGHT. 23.12Z GFS/NAM/ECMWF/GEM ARE IN GOOD
AGREEMENT THROUGH 26.12Z...DIVERGING SOMEWHAT THEREAFTER WITH THE
LATE WEEK SYSTEM. WILL USE A BLENDED MODEL SOLUTION.
FOR TONIGHT...SURFACE LOW CURRENTLY ACROSS CENTRAL WI WILL QUICKLY
EJECT INTO SOUTHEAST ONTARIO. DEFORMATION PRECIPITATION AXIS WILL
CONTINUE TO DISSIPATE ACROSS THE FORECAST AREA...BUT WITH MODEL
SOUNDINGS SUGGESTING A LOSS OF ICE IN THE CLOUD...WILL TRANSITION
FROM RAIN/SNOW THIS EVENING TO MAINLY DRIZZLE AFTER MIDNIGHT.
SURFACE TEMPERATURES WILL HOVER RIGHT AROUND THE FREEZING
MARK...SO THERE COULD BE SOME PATCHY ICING FOR ANY AREA THAT
EXPERIENCES MORE CONTINUOUS DRIZZLE. OTHERWISE...CONDITIONS SHOULD
GRADUALLY IMPROVE WITH ONLY MINOR ADDITIONAL SNOW ACCUMULATION.
A STRONG SECONDARY SURFACE LOW WILL SURGE NORTHWARD AND ACROSS
MICHIGAN ON WEDNESDAY AS THE PRIMARY TROUGH ALOFT LIFTS INTO THE
GREAT LAKES REGION. THE PRECIPITATION SHIELD WITH THIS SYSTEM
WILL PRIMARILY IMPACT IL/EASTERN WI AND INTO IN/MI...BUT ITS
WESTERN FLANK COULD CLIP THE EASTERN FORECAST AREA. MOST OF
WEDNESDAY WILL BE DRY...BUT KEPT 20 POPS EAST OF THE MISSISSIPPI
RIVER FOR SOME LIGHT SNOW AND POSSIBLE ACCUMULATIONS AROUND A
TENTH OR TWO. OTHERWISE...WEDNESDAY WILL BE CLOUDY WITH A MODEST
NORTHWEST BREEZE AND TEMPERATURES TOPPING OUT IN THE MID 30S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 202 PM CST TUE DEC 23 2014
CHRISTMAS DAY WILL BE MOSTLY CLOUDY...BUT DRY AS A SURFACE RIDGE
MOVES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. NO REAL CHANGE IN
AIR MASS...SO TEMPERATURES WILL REMAIN STEADY IN THE 30S.
THE NEXT PACIFIC TROUGH DIGS INTO THE SOUTHERN ROCKIES CHRISTMAS
NIGHT INTO FRIDAY WITH ITS SURFACE LOW MOVING FROM THE LEE OF THE
ROCKIES INTO THE UPPER MIDWEST. PRECIPITATION EXPECTED ALONG THE
850 TO 700 HPA THERMAL GRADIENT...BUT DIFFERENCES ARISE CONCERNING
ITS PLACEMENT. 23.12Z ECMWF/GEM KEEP MAJORITY OF PRECIPITATION
NORTH OF THE FORECAST AREA...WHERES THE GFS/NAM ARE A BIT MORE
BULLISH ON LIGHT QPF...ESPECIALLY FRIDAY AFTERNOON AND EVENING.
TRIMMED POPS ACROSS THE SOUTH ON FRIDAY...BUT KEPT 20-30 POPS
REGION-WIDE FRIDAY NIGHT FOR SOME LIGHT SNOW.
SATURDAY THROUGH TUESDAY WILL BE MOSTLY DRY AS A NORTHWEST FLOW
SYNOPTIC REGIME SETS-UP ACROSS THE UPPER MIDWEST. A COUPLE LIGHT
SNOW EPISODES ARE POSSIBLE...BUT DIFFERENCES IN TIMING AND
STRENGTH OF SHORT-WAVES ROTATING AROUND THE PARENT HUDSON BAY
TROUGH LENDS ITSELF TO LOW CONFIDENCE AND ONLY 20 POPS MONDAY/
MONDAY NIGHT. BIGGER STORY WILL BE MUCH COOLER TEMPERATURES WITH
DAILY HIGHS IN THE UPPER TEENS AND 20S AND NIGHTTIME LOWS IN THE
SINGLE DIGITS TO TEENS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 520 PM CST TUE DEC 23 2014
LOW MVFR/IFR CIGS EXTENDED WELL WEST INTO THE DAKOTAS AND CENTRAL
PLAINS EARLY THIS EVENING...PER LATEST SFC OBS AND FOG/STRATUS
SATELLITE IMAGERY. NAM RH FIELDS/BUFKIT SOUNDINGS SUGGEST NO CHANGE
IN THE LOW CIGS UNTIL CHRISTMAS NIGHT...WHILE THE GFS POINTS TO A
POSSIBLE BREAK BY XMAS MORNING. GOING TO STAY ON THE PESSIMISTIC
SIDE.
WITH THE AMPLE LOW LEVEL MOISTURE HOLDING FAST UNDER THE
INVERSION...COULD HAVE SOME VSBY REDUCTIONS FROM BR AND POTENTIALLY
-DZ. RAP POINTS TO SOME ISENTROPIC LIFT THROUGH THE SATURATED LAYER
THROUGH THE NIGHT...WHILE THE NAM HINTS AT WEAK FRONTOGENETIC LIFT
AROUND A SFC BOUNDARY. BUFKIT SOUNDINGS FAVORING NO ICE IN THE
CLOUD...AND THUS -DZ FOR ANY PCPN TYPE. SFC TEMPS STAYING ABOVE
FREEZING FOR THE MOST PART. WILL NOT ADD PCPN TO THE FORECAST RIGHT
NOW...BUT IT NEEDS WATCHING. WILL ADD IN SOME MVFR BR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
1134 PM CST TUE DEC 23 2014
.AVIATION...
CLOUDS WILL CONTINUE OVER THE AREA TONIGHT AND MUCH OF WEDNESDAY.
THE UPPER LEVEL LOW CONTINUES WEST OF ARKANSAS AND WILL SLOWLY MOVE
EAST. LIGHT RAIN WILL REDEVELOP OVERNIGHT AND CONTINUE SPORADICALLY
THROUGH THE FIRST HALF OF WEDNESDAY. CLOUDS WILL BREAK UP LATE IN
THE AFTERNOON AND EVENING. VFR CONDITIONS WILL BECOME MVFR TO LIFR.
&&
.PREV DISCUSSION... /ISSUED 814 PM CST TUE DEC 23 2014/
DISCUSSION...
MOISTURE CHANNEL IMAGERY REVEALS THE LOCATION OF THE MID LEVEL
TROUGH QUITE EASILY AS IT ROTATES THROUGH THE CENTRAL AND SOUTHERN
PLAINS. ANOTHER ROUND OF RAIN IS EXPECTED OVER MAINLY THE EASTERN
HALF OF THE STATE TONIGHT AS THE TROUGH LIFTS THROUGH. STILL
LOOKING AT A LITTLE MIX ON THE TAIL END OF THE SYSTEM AS IT PULLS
OUT BUT LITTLE IF ANY ACCUMULATION EXPECTED.
FORECAST IN GOOD SHAPE BUT WEATHER/POP GRIDS WERE REWORKED TO
REFLECT CURRENT TRENDS AND HRRR SOLUTION. ALL OTHER FORECAST
ELEMENTS LEFT AS IS AND ALL UPDATES ARE OUT.
PREV DISCUSSION... /ISSUED 556 PM CST TUE DEC 23 2014/
AVIATION...
AN UPPER TROUGH REMAINS JUST WEST OF ARKANSAS THIS EVENING. CLOUDS
WILL CONTINUE ACROSS THE AREA AND CEILINGS WILL LOWER OVERNIGHT.
RAIN CHANCES WILL ALSO INCREASE OVERNIGHT AND CONTINUE INTO
WEDNESDAY MORNING. CLOUDS COULD BREAK UP LATE IN THE PERIOD. LIFR
TO MVFR CONDITIONS ARE MAINLY EXPECTED.
PREV DISCUSSION... /ISSUED 255 PM CST TUE DEC 23 2014/
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
UPR LVL TROF RMND SITUATED TO THE W OF AR THIS AFTN. THIS RESULTING
SWLY FLOW ALOFT WAS BRINGING ANOTHER SHRTWV THRU THE FA WITH ASSOCD
RAINFALL NOW WORKING ACRS CNTRL AR. SUBSIDENCE BEHIND THE SHRTWV HAS
RESULTED IN SOME BINOVC OVR PARTS OF WRN AR AT MID AFTN.
MEANWHILE...CDFNT WAS LOCATED WELL E OF THE AREA WITH N/NWLY WINDS
ALLOWING COOLER AIR TO ADVECT INTO THE STATE.
THE AFOREMENTIONED SHRTWV WL CONT TO LIFT NEWD OUT OF THE AREA THIS
EVENING. ANTICIPATE A LULL IN THE PRECIP THIS EVENING AND PLAN TO
ADJUST EVENING POPS BASED ON RADAR TRENDS. BY LATER TNGT AND ON
WED...THE MAIN UPR TROF WL SHIFT EWD THRU THE MID SOUTH. ANOTHER
ROUND OF RAIN WL ACCOMPANY THIS SYS...WITH THE HIGHEST POPS
MENTIONED FOR THE ERN HALF OF THE FA.
RAIN CHCS WL DIMINISH FM THE SW ON WED AS THE UPR LVL SYS AND ASSOCD
SFC LOW LIFT NEWD AWAY FM THE FA. CURRENT FCST TRENDS STILL LOOK
GOOD INDCG SMALL POPS ACRS NRN AR WED AFTN. ONE CONCERN STILL
LINGERS REGARDING THE CHC OF SOME WET SNOW ACRS PARTS OF WRN AND NRN
AR LATE TNGT AND WED MRNG AS COLDER AIR ALOFT /ASSOCD WITH THE UPR
TROF/ MOVES OVR THE AREA. MODEL DATA CONT TO SHOW THAT SFC TEMPS WL
STAY ABV FRZG IN MOST LOCATIONS FOR MUCH IN THE WAY OF ANY SNOW
ACCUMULATION. HOWEVER...SOME OF THE HIGHER ELEVATIONS COULD SEE A
BURST OF WET SNOW BEFORE ENDING...WITH POSSIBLY SOME MINOR
ACCUMULATION ON GRASSY SURFACES.
THE STORM SYS WL CONT TO PULL AWAY FM THE REGION WED NGT AND THU...
WITH DRIER CONDS RETURNING. THIS WL BE SHORT LIVED THOUGH AS YET
ANOTHER FAST MOVG STORM SYS WL BRING RAIN CHCS BACK THE NATURAL
STATE FRI AND FRI NGT.
LONG TERM...SATURDAY THROUGH TUESDAY
ON SATURDAY A STORM SYSTEM AND COLD FRONT WILL BE MOVING THROUGH THE
REGION...AND FORECAST HAS A GOOD CHANCE OF RAIN. MAINLY A SHOWER
EVENT...WHILE THE GFS CONTINUES TO BE FASTER THEN THE EURO. HAVE
TRENDED TO THE SLOWER EURO AND KEEP MORE PRECIP OVER AR THROUGH
SUNDAY...THEN THE PRECIP GRADUALLY MOVING OUT OF AR LATER SUNDAY.
THE UPPER LOW PRESSURE TROUGH LAGS THE SURFACE SYSTEM AND HENCE
HOLDING OF THE PRECIP ON SUNDAY BEFORE MOVING EAST. IN THE OVERNIGHT
AND EARLY MORNING PERIODS...SOME LOW CHANCES OF A WINTRY MIX WILL BE
POSSIBLE...MAINLY OVER WEST CENTRAL...TO THE NORTHERN HALF OF
AR...AS TEMPS LOWER TO AROUND THE FREEZING MARK. LITTLE TO NO
SIGNIFICANT AMOUNTS ARE EXPECTED. DRY AND COOL MONDAY...BUT SOME
CLOUDS WILL STILL BE SEEN UNTIL THE UPPER TROUGH TOTALLY EXISTS
EAST. TUESDAY MAY SEE A REINFORCING SHOT OF COLD AIR BUT SOME
UNCERTAINTY DOES EXIST IN THE FORECAST THIS FAR OUT IN THE FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 50 38 44 31 / 60 60 40 10
CAMDEN AR 52 38 47 31 / 60 50 20 0
HARRISON AR 52 34 39 28 / 20 30 40 10
HOT SPRINGS AR 49 37 45 30 / 60 40 20 0
LITTLE ROCK AR 51 39 46 31 / 60 50 20 0
MONTICELLO AR 56 41 47 33 / 60 60 20 0
MOUNT IDA AR 51 35 43 28 / 60 30 20 0
MOUNTAIN HOME AR 50 36 41 29 / 30 40 40 10
NEWPORT AR 49 39 45 31 / 60 60 40 10
PINE BLUFF AR 51 40 47 32 / 60 60 20 0
RUSSELLVILLE AR 51 37 44 28 / 50 40 20 0
SEARCY AR 50 39 45 29 / 60 60 30 10
STUTTGART AR 50 40 46 31 / 60 60 30 0
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...65
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
141 AM EST WED DEC 24 2014
.PREV DISCUSSION... /ISSUED 748 PM EST TUE DEC 23 2014/
UPDATE...
LINE OF STRONG TO SEVERE THUNDERSTORMS ACROSS CENTRAL AL CONTINUES
EASTWARD THIS EVENING. THE LINE IS HOLDING STEADY AND IS EXPECTED
TO REACH THE AL/GA STATE LINE AROUND 10 PM. THE HRRR BEGINS TO
WEAKEN THE LINE RIGHT ALONG THE INTERSTATE 85 CORRIDOR RIGHT
AROUND OR JUST AFTER MIDNIGHT. GRADUAL WEAKENING OF THE LINE WOULD
OCCUR IF THE WEDGE CONTINUED TO HOLD STRONG EAST OF 85.
HOWEVER...STORMS SHOULD BECOME ELEVATED ACROSS THE EASTERN
PORTIONS OF THE CWFA. DO THINK SOME CONTINUED EROSION ON THE WEST
SIDE OF THE WEDGE IS LIKELY...BUT NOT CONFIDENCE ON EXACTLY HOW
MUCH.
HAVE MADE SOME TIMING TWEAKS FOR TSRA WITHIN THE GRIDS. IN
ADDITION...TWEAKED THE HOURLY TEMP/DEW GRIDS ACCORDING TO THE
POSITION OF THE WARM FRONT.
PREV DISCUSSION... /ISSUED 622 PM EST TUE DEC 23 2014/
PREV DISCUSSION... /ISSUED 244 PM EST TUE DEC 23 2014/
SEVERE STORMS REMAIN POSSIBLE TONIGHT AND WEDNESDAY...
HEAVY RAINFALL AND MINOR FLOODING LIKELY TONIGHT AND
WEDNESDAY...
SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
OVERALL FCST IN GOOD SHAPE. WARM FRONT STILL VERY SLOW TO MOVE
NORTH BUT SHOULD MARCH SLOWLY NORTH TONIGHT.
MONITORING SEVERE STORM IN NW GA THAT HAS HISTORY OF PRODUCING
DAMAGING WINDS. STORM MAY HAVE TRAVELED ALONG WRN PERIPHERY OF
WEDGE. WILL BE A FEW HOURS BEFORE NORTH GA SEES ANOTHER ROUND OF
POSSIBLE SVR STORMS. AS MENTIONED IN PREV DISCUSSION /SEE UPDATE
SECTION BELOW/ INGREDIENTS REMAIN IN PLACE FOR SVR STORMS TONIGHT
AND WED MORNING...GREATEST THREAT 03Z-15Z OR SO.
AS FRONT SWEEPS THRU WED AFTERNOON...SHOULD SEE RAPID END TO PRECIP
AND ERODING OF LOW CLOUDS. NOT MUCH CHC FOR WINTER PRECIP WED NIGHT
EVEN IN HIGHER ELEVATIONS. SOME IN ELEV ABOVE 2500FT MAY SEE A BRIEF
MIX OF LIGHT RAIN WITH SNOW FLURRIES BUT NO IMPACTS EXPECTED.
SNELSON
UPDATE...
/ISSUED AT 129 PM EST TUE DEC 23 2014/
FCST GRIDS UPDATED EARLIER THIS MORNING TO ACCOUNT FOR OBSERVED
TRENDS. 12Z MODELS...PARTICULARLY GFS...TOO QUICK LIFTING WARM
FRONT WHICH IS CURRENTLY LOCATED FROM AROUND COLUMBUS TO VIDALIA.
TEMPS WILL LIKELY REMAIN IN THE 40S IN NORTH GA AND 50S TO 60S
OVER MIDDLE GA.
COVERAGE OF RAINFALL OVER AL A LITTLE LESS THAN WHAT 12Z HIRES
MODELS INDICATING...POSSIBLY DUE TO LARGE EXPANDING AREA OF
CONVECTION OVER SRN AL AND SW GA. NEW 18Z CYCLE WPC QPF GUIDANCE
INDICATING ABOUT 1-2 INCHES OVER AREAS NORTH OF COLUMBUS TO MACON.
WILL REVIEW THIS BEFORE RELEASING FINAL FORECAST. BASED ON PREV
FCST AND ALREADY SOME REPORTS OF NUISANCE/MINOR FLOODING HAVE
ISSUED FLOOD WATCH FOR ALL OF CWA.
THREAT FOR SEVERE WX STILL IN PLACE THOUGH CONCERNED ABOUT
POSSIBLE UPSTREAM CONVECTION MENTIONED EARLIER DISRUPTING VERTICAL
WIND SHEAR AND INSTABILITY. THAT SAID...STILL SEEING FAIRLY STRONG
ISOLATED CELLS IN NRN/WRN AL ATTM WHERE MLCAPE VALUES TRYING TO
CREEP UP TO 250-500 J/KG. 0-1KM BULK SHEAR ONLY 20-30KTS IN AL.
12Z MODEL VALUES FOR TONIGHT SILL FAVORABLE FOR HIGH SHEAR LOW
CAPE CONVECTION AND QLCS MODES. NAM STILL HIGHER THAN GFS FOR
SHEAR AND MLCAPE...AVERAGING AROUND 100-300 J/KG MLCAPE AND 35-45
FOR 0-1KM BULK SHEAR. SHEAR DROPS SOME DURING DAY ON WED SO
TORNADO THREAT MAY LOWER ACCORDINGLY.
CONTINUING TO MONITOR.
SNELSON
LONG TERM /THURSDAY THROUGH TUESDAY/...
BEHIND A COLD FRONT THAT PUSHES EAST OF THE AREA EARLY THURSDAY
MORNING... WRAP AROUND CLOUDS AND MOISTURE MAY BE A BIT SLOW TO
CLEAR FROM WEST TO EAST THURSDAY MORNING DUE TO A LAGGING STRONG
UPPER DISTURBANCE THAT DOES NOT PUSH EAST OF THE STATE UNTIL EARLY
THURSDAY AFTERNOON. OTHERWISE... EXPECT DRY HIGH PRESSURE TO BUILD
OVER THE AREA THURSDAY AFTERNOON WITH CLEARING CONDITIONS AND HIGH
TEMPERATURES MOSTLY IN THE 50S. THE COOLEST TEMPERATURES WILL BE
FELT FRIDAY MORNING WITH LOWS MOSTLY IN THE 30S. THEN MODELS AGREE
ON THE SURFACE RIDGE SHIFTING EAST ON FRIDAY...AND ESTABLISHING A
WARMING...MOIST SOUTHERLY FLOW GOING INTO THE WEEKEND. THIS AHEAD OF
ANOTHER LOW PRESSURE SYSTEM THAT SHOULD BRING RAIN CHANCES TO THE
AREA OVER THE WEEKEND. LONG RANGE MODELS STILL SHOW SOME TIMING
DIFFERENCES... WITH THE FASTER GFS SPREADING SHOWERS INTO THE AREA
ON SATURDAY...AND HOLDING RAIN CHANCES ACROSS THE AREA INTO MONDAY
WHEN A SLOW MOVING COLD FRONT FINALLY TRAVERSES THE AREA. THE SLOWER
ECMWF HOLD RAIN CHANCES OFF UNTIL MAINLY SUNDAY...BUT THEN DOES SHOW
A COLD FRONT PUSHING ACROSS THE AREA MONDAY NIGHT-EARLY TUESDAY...
WITH BOTH SHOWING HIGH PRESSURE AND DRIER CONDITIONS IN CONTROL BY
TUESDAY. AT THIS TIME... LACK OF INSTABILITY AND STRONG UPPER
FORCING WARRANTS ONLY SHOWERS SO FAR WITH THIS SYSTEM... HOWEVER
THIS COULD CHANGE SO STAY TUNED.
39
HYDROLOGY...
DECIDED TO PLAY IT SAFE AND POST A FLOOD WATCH FOR MOST OF NORTH
AND CENTRAL GA THROUGH 8 PM WEDNESDAY DUE TO THE EXPECTED 2 TO 3
INCHES OF ADDITIONAL RAINFALL THROUGH WEDNESDAY AFTERNOON AHEAD OF
A COLD FRONT. ISOLATED HIGHER AMOUNTS ARE ALMOST CERTAIN... AND
WITH NEARLY 100 PERCENT RUNOFF OF ANY RAINFALL INTO CREEKS...
STREAMS AND RIVERS THIS TIME OF YEAR... RAPID RISES ARE
EXPECTED...THAT COULD RESULT IN FLOODING. IN ADDITION TO RIVER
FLOODING... ISOLATED FLASH FLOODING IS ALSO POSSIBLE DUE TO FALL
VEGETATION AND OTHER DEBRIS CLOGGING DRAINAGE SYSTEMS OR NARROWS
ALONG CREEKS AND STREAMS. ALL INTEREST ACROSS NORTH AND CENTRAL GA
SHOULD MONITOR CONDITIONS CLOSELY AND BE ALERT FOR POSSIBLE FLOOD
WARNINGS. THOSE LIVING IN AREAS PRONE TO FLOODING SHOULD BE
PREPARED TO TAKE ACTION SHOULD FLOODING DEVELOP. THE RAINFALL
SHOULD END FROM WEST TO EAST WEDNESDAY AFTERNOON AND GREATLY
LESSON THE THREAT OF FLOODING BY WEDNESDAY EVENING.
&&
.AVIATION...
06Z UPDATE...
MAIN LINE OF CONVECTION SWEEPING THROUGH THE AREA THIS MORNING
WITH SHOWERS CONTINUING BEHIND IT. WILL CONTINUE TO SEE SHOWERS
OFF AND ON IN THE ATL AREA THROUGH MIDDAY. WINDS ARE CURRENTLY OUT
OF THE EAST. THEY WILL TURN TO THE SE THEN SW AND EVENTUALLY WEST
THROUGH THIS TAF PERIOD. WIND SPEEDS EXPECTED TO INCREASE THIS
AFTERNOON AFTER THE FRONT PASSES THROUGH WITH 10KTS GUSTING TO
20KT. THE GUST WILL SUBSIDE OVER NIGHT. CEILINGS EXPECTED TO STAY
FAIRLY LOW THROUGH THE PERIOD LIFTING TO VFR BY THE VERY END OF
THIS TAF SET.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM TO HIGH CONFIDENCE ON ALL ELEMENTS.
01
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 66 40 55 32 / 100 30 5 0
ATLANTA 65 39 53 36 / 80 10 0 0
BLAIRSVILLE 58 35 49 29 / 80 30 5 0
CARTERSVILLE 64 37 51 29 / 80 10 0 0
COLUMBUS 66 40 56 34 / 80 10 5 0
GAINESVILLE 61 39 53 34 / 90 30 0 0
MACON 68 41 58 31 / 100 20 5 0
ROME 62 37 51 28 / 70 10 0 0
PEACHTREE CITY 66 37 54 28 / 80 10 0 0
VIDALIA 71 47 59 37 / 100 30 5 0
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH THIS EVENING FOR THE FOLLOWING ZONES:
BALDWIN...BANKS...BARROW...BARTOW...BIBB...BLECKLEY...BUTTS...
CARROLL...CATOOSA...CHATTAHOOCHEE...CHATTOOGA...CHEROKEE...
CLARKE...CLAYTON...COBB...COWETA...CRAWFORD...CRISP...DADE...
DAWSON...DE KALB...DODGE...DOOLY...DOUGLAS...EMANUEL...FANNIN...
FAYETTE...FLOYD...FORSYTH...GILMER...GLASCOCK...GORDON...
GREENE...GWINNETT...HALL...HANCOCK...HARALSON...HARRIS...HEARD...
HENRY...HOUSTON...JACKSON...JASPER...JEFFERSON...JOHNSON...
JONES...LAMAR...LAURENS...LUMPKIN...MACON...MADISON...MARION...
MERIWETHER...MONROE...MONTGOMERY...MORGAN...MURRAY...MUSCOGEE...
NEWTON...NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PEACH...
PICKENS...PIKE...POLK...PULASKI...PUTNAM...ROCKDALE...SCHLEY...
SOUTH FULTON...SPALDING...STEWART...SUMTER...TALBOT...
TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...TOWNS...TREUTLEN...
TROUP...TWIGGS...UNION...UPSON...WALKER...WALTON...WARREN...
WASHINGTON...WEBSTER...WHEELER...WHITE...WHITFIELD...WILCOX...
WILKES...WILKINSON.
TORNADO WATCH UNTIL 7 AM EST THIS MORNING FOR THE FOLLOWING
ZONES: CRISP...DODGE...DOOLY...MACON...MONTGOMERY...PULASKI...
SCHLEY...SUMTER...TELFAIR...WHEELER...WILCOX.
&&
$$
SHORT TERM...01
LONG TERM....BDL
AVIATION...01
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1151 PM CST TUE DEC 23 2014
.SHORT TERM /TONIGHT/...
ISSUED AT 313 PM CST TUE DEC 23 2014
PRECIP TRENDS WILL REMAIN THE PRIMARY FOCUS AGAIN TONIGHT. LIGHT
SNOW CONTINUES TO DRIFT NE-SW ACROSS THE NW HALF OF IA DRIVEN
MAINLY BY MID LEVEL KINEMATIC FORCING WITH WEAK DEFORMATION AND
DIFFERENTIAL POSITIVE VORTICITY ADVECTION NORTH OF IA PV ANOMALY
NOTED IN RAP ANALYSIS AND SUGGESTED BY PIVOT POINT IN WATER VAPOR
IMAGERY. THERE IS LITTLE THERMODYNAMIC COMPONENT AT THIS POINT.
PRECIP IS QUITE LIGHT WITH WEAK REFLECTIVITY...EVEN IN LONG
PULSE/VCP 31. WEBCAMS SHOW CURRENT VISIBILITY RESTRICTIONS ARE AS
MUCH DUE TO FOG AS SNOW WITH LITTLE SNOW NOTED. THIS WEAK FORCING
WILL REMAIN ESSENTIALLY STEADY STATE AS IT DRIFTS SLOWLY SOUTH AND
EAST THROUGH THE NIGHT BEFORE THE NEXT SHORT WAVE/PV ANOMALY
ROUNDS THE BASE OF THE TROUGH AND RE-ENERGIZES SYSTEM AGAIN TO OUR
SOUTH AND EAST TOWARD 12Z. SE FRINGE OF PRECIP SHIELD WILL BE A
RAIN/SNOW MIX WITH RAIN/SNOW LINE DRIFTING SE. ONLY LIGHT QPF
AMOUNTS AND TEMPERED SNOW RATIOS WILL RESULT ANY ADDITIONAL ACCUMS
BEING UNDER AN INCH AND MAINLY ON GRASSY OR ELEVATED SURFACES.
ROAD TEMPS REMAIN WET AND 35F PLUS SO MUCH OF SNOW WILL MELT ON
ROADS. MID LEVEL MOISTURE WILL BE LACKING SE WITH LITTLE ICE
INTRODUCTION SO PRECIP WILL GENERALLY REMAIN LIQUID/DRIZZLE SOUTH
AND EAST OF DES MOINES.
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
ISSUED AT 313 PM CST TUE DEC 23 2014
THE LONG TERM PORTION OF THE FCST PD WILL BE CHARACTERIZED BY
MINIMAL PRECIPITATION...ALONG WITH ABOVE NORMAL TEMPERATURES LATE
THIS WEEK FOLLOWED BY TEMPERATURES GOING BELOW NORMAL BEGINNING
THIS WEEKEND AND CONTINUING INTO NEXT WEEK.
MODELS IN GOOD AGREEMENT WITH THE CENTRAL CONUS SHORTWAVE ENERGY
DEVELOPING A SFC LOW ACROSS THE SOUTHERN U.S. TONIGHT...BRINGING
IT NORTH-NORTHEAST INTO THE EASTERN GREAT LAKES AND DEEPENING BY
THURSDAY. GREATEST SYNOPTIC FORCING AND MOISTURE WILL REMAIN TO
THE EAST OF THE CWA. MODELS SHOWING REMNANT AREA OF WEAK LIFT AND
MOISTURE IN E/SE CWA THRU WED MORNING...SO HAVE KEPT CHC/SLIGHT
CHANCE POPS THERE. PCPN IS EXPECTED TO BE LIGHT.
ATTENTION THEN TURNS TO THE NEXT WX SYSTEM TO AFFECT OUR REGION.
CENTRAL U.S. SHORTWAVE LIFTS OUT AND ANOTHER SHORTWAVE ENTERS THE
WESTERN U.S. BY THURSDAY. MODELS BEGIN DIVERGING ON THE SPEED AND
STRENGTH OF THIS SHORTWAVE ONCE IT ARRIVES. GFS PRESENTS A FASTER
AND WEAKER SOLUTION...WITH THE ECMWF HOLDING THE ENERGY BACK FOR
LONGER. THE DIVERGING SOLUTIONS IMPACT SFC FEATURES AS WELL...WITH
THE GFS BRINGING A STRONGER SFC SYSTEM THROUGH OUR REGION AND
FASTER VS. THE ECMWF. HAVE TRENDED SLOWER THAN THE GFS GIVEN ITS
RECENT PERFORMANCE...BRINGING -SN INTO THE CWA BEGINNING 12Z FRI.
PRIOR TO THE PRECIP/S ARRIVAL...THOUGH...STRONG WAA WILL PUSH
THURSDAY/S MAXES INTO THE MIDDLE 30S AND 40S. ATTM THE BULK OF THE
PRECIP IS EXPECTED TO REMAIN NW OF THE CWA...WITH BEST COMBINATION
OF FORCING AND MOISTURE MOVING ACROSS THE CWA FRI AFTN AND FRIDAY
NIGHT. ALTHOUGH POPS ARE RELATIVELY LOW...THERE IS THE POTENTIAL
FOR A BRIEF PERIOD OF LIFT TO COINCIDE WITH ELEVATED RH LEVELS
WITHIN THE DGZ ESPECIALLY ACROSS NW IOWA.
MODEL SOLUTIONS DIVERGE FURTHER WITH TIME INTO THE WEEKEND SO
FORECAST CONFIDENCE DECREASES. GFS KEEPS OUR REGION IN CYCLONIC
FLOW WITH WEAK SHORTWAVES WHILE THE ECMWF BRINGS MORE FOCUSED
SHORTWAVE ENERGY THROUGH OUR REGION MONDAY. HAVE TENDED TOWARD THE
ECMWF AND HAVE SLIGHT CHANCE POPS FOR THIS TIME PD. LITTLE IF ANY
SNOWFALL ACCUMULATIONS ARE AGAIN EXPECTED GIVEN THE BEST FORCING
BEING OUT OF PHASE WITH ELEVATED MOISTURE LEVELS. TEMPERATURES
WILL BEGIN A DOWNWARD TEND AS NORTHWEST FLOW ALOFT PREVAILS.
&&
.AVIATION...24/06Z
ISSUED AT 1146 PM CST TUE DEC 23 2014
BAND OF LIFR CONDITIONS IN SNOW AND STRATUS WILL CONTINUE TO SINK
SOUTHEAST WITH CONDITIONS BECOMING MVFR FROM THE NORTHWEST LATE
TONIGHT AND WED. VFR CONDITIONS WILL REACH THE FAR WEST LATE IN
THE TAF PERIOD AS HIGH PRESSURE RIDGE AXIS REACHES CENTRAL IA.
OUTLOOK...VFR CONDITIONS WILL OVERSPREAD THE AREA WEDNESDAY NIGHT
AND CHRISTMAS DAY WITH VFR CONTINUING INTO FRIDAY.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...ZOGG
AVIATION...MS DEC 14
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1145 PM CST TUE DEC 23 2014
.UPDATE...
ISSUED AT 943 PM CST TUE DEC 23 2014
BAND OF SNOW CONTINUES FROM PORTIONS OF NORTHEAST-CENTRAL-SOUTHWEST
IA WITHIN ZONE OF WEAK ISENTROPIC LIFT ON BACKSIDE OF UPPER TROUGH
AXIS. THIS LIFT DEPICTED WELL ON 295K SFC OF NAM AND RAP MODELS
AND IS SHOWN TO GRADUALLY WEAKEN OVERNIGHT REMAINING MAINLY WEST OF
CWA ALTHOUGH POSSIBLY BRUSHING FAR WEST SECTIONS... ALONG/W OF
IIB-VTI-OOA LINE WITH FLURRIES OR VERY LIGHT SNOW. OTHERWISE...SOME
PATCHY DRIZZLE WAS NOTED ALONG MISSISSIPPI RIVER AHEAD OF FRONT
AND THIS MAY CONTINUE NEXT FEW HOURS BEFORE SHIFTING EAST WITH THE
FRONT... THEN ASIDE FROM FAR WESTERN CWA REST OF THE NIGHT APPEARS
TO BE MAINLY DRY. AS RESULT... HAVE UPDATED TO REMOVE ANY MEASURABLE
POPS REST OF TONIGHT. ALSO...WITH CONSIDERABLE CLOUDS AND FAIRLY
WEAK COLD ADVECTION HAVE NUDGED UP MINS WITH MOST AREAS STAYING AT
OR ABOVE 32F.
AS FOR TOMORROW /CHRISTMAS EVE/ SYSTEM... SOME OF THE LATEST MODEL
GUIDANCE OF RAP...NAM AND GFS MODELS TAKE THE STORM SLIGHTLY
FURTHER EAST AND SUGGEST MAY NOT EVEN SEE FAR EAST BRUSHED BY ANY
SNOW. MAY SEE SOME FLURRIES AND POSSIBLY FEW SNOW SHOWERS IF
SUFFICIENT MOISTURE DEPTH BUT ASIDE FROM BRIEF REDUCTION IN VSBY
(SHOULD THE SNOW SHOWERS OCCUR) NO IMPACTS EXPECTED WITH TEMPS ABOVE
32F. HAVING SAID THAT... ANYONE WITH TRAVEL INTERESTS TO OUR EAST
TOMORROW WILL WANT TO STAY UPDATED AS POSSIBILITY OF IMPACTS TO TRAVEL
FROM WET/SLUSHY ROADS AND LIMITED VISBILITIES AT TIMES.
&&
.SYNOPSIS...
ISSUED AT 312 PM CST TUE DEC 23 2014
SYNOPSIS...AT 3 PM CST..A WEAK COLD FRONT BISECTED THE DVN CWA.
THICK OVERCAST WAS OBSERVED TO THE NW OF THE BOUNDARY WITH TEMPS
IN THE MID TO UPPER 30S. TO THE SE...IN A SOUTHWEST SFC WIND FLOW
SKIES WERE SCT TO BKN AND TEMPS WERE IN THE LOWER TO MIDDLE
40S...AND A LIGHT RAIN SHOWERS WAS LOCATED NEAR IOWA CITY. A
DEVELOPING SFC LOW PRESSURE SYSTEM WILL MOVE NORTHEASTWARD ON
WEDNESDAY AFTN AND NIGHT...BUT WILL REMAIN WELL EAST OF E IOWA AND
W ILLINOIS. THERE IS A CHANCE FOR LIGHT SNOW ACCUMULATIONS ACROSS
THE FAR EASTERN CWA WITH THIS SYSTEM. HOWEVER HIGH TEMPS IN THE
MID 30S SHOULD LIMIT THE OVERALL IMPACT FROM ANY SNOW THAT FALLS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 312 PM CST TUE DEC 23 2014
TONIGHT...AS THE COLD FRONT SLIDES EAST OF THE AREA AFTER MIDNIGHT
SFC WINDS WILL VEER FROM THE SW TO THE NW AND THE STRATUS WILL
OVERSPREAD THE ENTIRE CWA. NAM FORECAST SFC DEWPOINT DEPRESSIONS ARE
NEAR 1-2 F OVERNIGHT BUT NW FLOW WILL LEAD TO SLOWLY DECREASING
MOISTURE THROUGH THE NIGHT SO NOT EXPECTING MUCH FOR FOG. A FEW
LIGHT RAIN/SNOW SHOWERS WILL BE POSSIBLE AS THE 850 MB TROUGH AXIS
SWINGS THROUGH BUT MANY AREAS WILL REMAIN DRY. NO SNOW ACCUMULATION
IS EXPECTED.
WEDNESDAY...PROMINENT LONGWAVE TROUGH ACROSS THE CENTRAL U.S.
DIPPING ALL THE WAY DOWN TO THE GULF OF MEXICO ALONG WITH A
STRENGTHENING JET STREAK ON ITS EASTERN FLANK AND BURGEONING
CONVECTION ACROSS THE SOUTHERN U.S. WILL INDUCE AN AREA OF
CYCLOGENESIS IN THE WESTERN OHIO VALLEY/GREAT LAKES. THE SFC LOW
IS FORECAST TO TRACK FROM N LOUISIANA TO N LOWER MICHIGAN.
MODEL DISCREPANCIES...12.23/12Z NAM AND GFS WERE THE FURTHEST WEST
WITH THE LOW TRACK FROM NE INDIANA TO NE LOWER MICHIGAN AND HAVE
THE GREATEST POTENTIAL FOR A PERIOD OF SNOW IN MY EASTERN CWA. THE
ECMWF AND GEM ARE FURTHER EAST WITH THE TRACK AND BRING VERY LIGHT
SNOW POTENTIAL WITH LESS THAN 0.10 INCHES OF QPF IN MY EASTERN
COUNTIES. THE HI-RES WRF-NMM HAS THE STEADY PRECIP DEFORMATION
BAND AFFECTING EASTERN BUREAU AND ALL OF PUTNAM COUNTY WITH STRONG
700-500 MB FRONTOGENESIS. THE 18Z NAM HAS NOW SHIFTED SLIGHTLY
EAST SO MODELS OVERALL IN FAIRLY GOOD AGREEMENT AT THIS POINT.
CWA IMPACTS...BEST CHANCES FOR ACCUMULATING SNOW WILL BE IN BUREAU
AND PUTNAM COUNTIES. A FEW FACTORS TO CONSIDER ARE THE RELATIVELY
WARM GROUND WITH THE PROLONGED PERIOD OF TEMPS IN THE 40S THE LAST
FEW DAYS AND FORECAST MAX TEMPS ABOVE FREEZING TOMORROW AFTN.
SINCE THERE IS NO COLD AIR IN PLACE...DYNAMIC COOLING IS NECESSARY
FOR SNOW TO OCCUR. BEST FORECAST AT THIS TIME IS FOR PERIOD OF
LIGHT SNOW TO IMPACT THE FAR EAST DURING THE AFTN WITH
ACCUMULATIONS POSSIBLY UP TO AN INCH OR TWO OF WET SNOW WITH SLRS
AT 9:1 OR SLIGHTLY LOWER...AND FLURRIES OR SCT SNOW SHOWERS
POSSIBLE ELSEWHERE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 245 PM CST TUE DEC 23 2014
MAIN FORECAST CONCERN IN THE EXTENDED PERIOD IS THE NEXT SYSTEM
THAT WILL AFFECT THE AREA ON FRIDAY AND INTO SATURDAY MORNING.
THIS SYSTEM LOOKS TO BRING US A CHANCE OF RAIN AND SNOW MIXED IN
FOR FRIDAY NIGHT INTO SATURDAY.
CHRISTMAS DAY IS A DRY DAY BETWEEN TWO STORM SYSTEMS. UNFORTUNATELY
AT THIS TIME...IT LOOKS LIKE WE WILL HAVE A BROWN CHRISTMAS AND IT
DOES NOT LOOK LIKE WE WILL HAVE ANY APPRECIABLE SNOW IN THE
EXTENDED. WE COULD SEE THE SUN LATER IN THE DAY ON CHRISTMAS EVE.
USED CONSRAW AS A STARTING POINT FOR TEMPERATURES SINCE BOI VERIFY
SUGGESTED IT HAS VERIFIED THE BEST RECENTLY.
FRIDAY...WARM AIR RETURNS TO THE AREA AS A LOW PRESSURE SYSTEM
PASSES TO OUR NORTH. TEMPERATURES SHOULD BE IN THE HIGH 40S. CLOUDS
RETURN LATER IN THE DAY ON FRIDAY AS ANOTHER STORM SYSTEM MAKES ITS
WAY INTO THE AREA. MODELS DIFFER ON THE TIMING OF PRECIP. THE GFS
HAS PRECIP ENTER THE CWA BEFORE 00Z SATURDAY. THE GFS APPEARS TO BE
FASTER THAN ALL OF THE MODELS...THIS IS THE CASE IN RESPECT TO THE
GEFS AS WELL. THE GEM AND ECMWF ARE CLOSER TO THE GEFS MEANS. SO
DECIDED TO EXCLUDE THE GFS FORECAST FOR PRECIP DURING THIS TIME.
LOOKS LIKE PRECIP MAKES ITS WAY IN AS A COLD FRONT APPROACHES THE
AREA. H92 TEMPS AND MODEL SOUNDINGS FROM THE GFS SUGGEST SNOW AT 03Z
ACROSS THE AREA...HOWEVER THE ECMWF WHICH HAS A MORE REASONABLE
SOLUTION SUGGESTS RAIN ACROSS EASTERN PORTIONS OF THE CWA FROM 00Z
TO 03Z WITH A RASN LINE MOVING EAST THROUGH THAT TIME. BY 12Z MOST
OF THE PRECIP WILL BE SNOW...WITH A FEW AREAS IN FAR EASTERN ZONES
STILL A RASN MIX.
LOOKING TOWARDS THE END OF THE EXTENDED PERIOD. A POLAR AIRMASS IS
FORECAST TO OCCUPY THE AREA TOWARDS NEW YEARS EVE. MODELS AGREE
THAT FLOW WILL BE OUT OF THE NW...SO TEMPS SHOULD BE COOLER THE
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1135 PM CST TUE DEC 23 2014
ANTICIPATE WIDESPREAD IFR TO LIFR CONDITIONS OVERNIGHT INTO WED AM
WITH ARRIVAL OF COLDER AIR AND ABUNDANT LOW LEVEL MOISTURE. SOME
IMPROVEMENT TO MVFR EXPECTED WED PM AND POSSIBLY INTO VFR WEST OF
THE MISSISSIPPI RIVER WED EVE. AN UPPER LEVEL TROUGH WILL MOVE
ACROSS THE REGION ON WED AND MAY BRING FLURRIES AND A FEW SNOW
SHOWERS TO THE AREA... BUT ENOUGH UNCERTAINTY WITH MOISTURE DEPTH
AND FORCING DUE TO DEEPENING LOW PASSING WELL EAST OF THE TERMINALS
PRECLUDES ANY MENTION MORE THAN JUST FEW FLURRIES ATTIM. TIGHTENING
PRESSURE GRADIENT WILL RESULT IN INCREASING NORTHWEST WINDS 10-15+
KTS AND GUSTY BY WED PM.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...05
SYNOPSIS...UTTECH
SHORT TERM...UTTECH
LONG TERM...GIBBS
AVIATION...05
AREA FORECAST DISCUSSION
NWS JACKSON KY
454 AM EST WED DEC 24 2014
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 316 AM EST WED DEC 24 2014
AREA OF LOW PRESSURE IS NOW STARTING TO MAKE ITS MOVE NORTH ACROSS
CENTRAL KENTUCKY...AND WILL END UP OVER SOUTHEAST MICHIGAN BY THIS
EVENING. STRONG LIFT ASSOCIATED WITH THE LOW PRESSURE SYSTEM WILL
SPREAD ACROSS THE AREA THROUGH DAYBREAK WITH RAIN BECOMING WIDESPREAD
ONCE AGAIN AFTER A BRIEF LULL OVER THE PAST FEW HOURS. HRRR AND RAP
ARE IN GOOD AGREEMENT THAT THIS LIFT WILL EXIT TO THE NORTH BY 9 OR
10 AM...WITH ANOTHER LULL IN PRECIPITATION EXPECTED THROUGH MIDDAY.
WITH THE MIDDAY LULL IN PRECIPITATION...HIGHS WILL WARM INTO THE 60S
FOR ONE MORE DAY.
FINALLY AS THE LOW SHIFTS NORTH THOUGH...A STRONG COLD FRONT WILL
PUSH EAST ACROSS THE AREA THIS AFTERNOON. WITH THE MILD
TEMPERATURES...WE MAY GENERATE SOME WEAK INSTABILITY TO SUPPORT
CONVECTIVE SHOWERS DEVELOPING ALONG THE FRONT AS IT PUSHES ACROSS THE
AREA. WHILE THUNDER CHANCES REMAIN LOW...CANNOT RULE OUT SOME THUNDER
WITH THE STRONGER CELLS...ESPECIALLY ACROSS NORTHERN KENTUCKY. GIVEN
THE ABUNDANCE OF MID LEVEL DRY AIR...AND STRONG 850MB WINDS AROUND 45
KNOTS...WE COULD SEE THE POTENTIAL FOR SOME HIGHER WINDS TO GET MIXED
DOWN WITH THE SHOWERS. HOWEVER...EVEN WITHOUT THE CONVECTIVE SUPPORT
FOR WINDS...THE SYNOPTIC SETUP BEHIND THE FRONT SHOULD SUPPORT 40+
MPH WINDS...ESPECIALLY ACROSS THE NORTHERN HALF OF THE AREA.
THUS...WILL GO AHEAD WITH A WIND ADVISORY FOR THE NORTHERN HALF OF
THE AREA. CONDITIONS ARE MORE MARGINAL FARTHER SOUTH...BUT A WIND
ADVISORY FOR THE HIGH TERRAIN NEAR THE VIRGINIA BORDER ALSO SEEMS IN
ORDER GIVEN THE STRONG WINDS AT 850MB. BEST THREAT FOR THE HIGHER
WINDS WILL BE AFTER 17Z AND BEFORE 03Z TONIGHT.
CONDITIONS WILL QUITE DOWN SOME THIS EVENING AS SUBSIDENCE SPREADS IN
BEHIND THE DEPARTING FRONT. HOWEVER...A SHORTWAVE TROUGH WILL PUSH
EAST ACROSS THE AREA LATE TONIGHT...WITH THE MOISTURE DEPTH
INCREASING TO SUPPORT SOME LIGHT RAIN/DRIZZLE. COLDER AIR WILL ALSO
BE SPILLING INTO THE AREA TONIGHT BEHIND THE FRONT. WHILE MOST AREAS
WILL STAY MILD ENOUGH FOR JUST RAIN...THE HIGHER TERRAIN IN THE
SOUTHEAST WILL SUPPORT SOME SNOW CHANCES. IN FACT...CONDITIONS ALIGN
GOOD ENOUGH TONIGHT WE COULD SEE A LIGHT COATING OF SNOW ON THE HIGH
TERRAIN ABOVE 2500 FEET LATE TONIGHT.
HEIGHTS WILL BE QUICK TO BUILD BACK ACROSS THE AREA ON CHRISTMAS.
CLOUDS MAY BE STUBBORN THROUGH THE FIRST HALF OF THE DAY...BUT WE
SHOULD DEFINITELY SEE A DECREASING TREND THROUGH THE AFTERNOON AND
EVENING AS THE RIDGE CENTERS ITSELF OVER THE REGION. HIGHS WILL
STRUGGLE TO WARM GIVEN THE ABUNDANCE OF CLOUDS THROUGH THE FIRST HALF
OF THE DAY...SO PLAN TO KEEP HIGHS LIMITED TO THE LOW TO MID 40S WITH
30S ON THE HIGHER TERRAIN IN THE SOUTHEAST.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 420 AM EST WED DEC 24 2014
THE PERIOD IS EXPECTED TO BEGIN WITH A CLOSED UPPER LOW CONTINUING TO
DEPART TO THE NORTHEAST OF THE REGION WITH UPPER LEVEL RIDGING
BUILDING ACROSS THE AREA AT THE START OF THE PERIOD. FURTHER TO THE
WEST A TROUGH IS EXPECTED TO EXTEND FROM THE NORTHERN PLAINS SOUTH
INTO THE SOUTHERN ROCKIES AND NORTHERN MEXICO. SFC AND UPPER LEVEL
RIDGING WILL GRADUALLY WORK ACROSS THE AREA FOR THU NIGHT INTO FRIDAY
AND THEN DEPART TO THE EAST FRIDAY NIGHT INTO SATURDAY. MEANWHILE A
SHORTWAVE TROUGH IS ANTICIPATED TO EJECT FROM THE WESTERN TROUGH
ACROSS THE PLAINS TOWARD THE GREAT LAKES FROM FRIDAY INTO SATURDAY.
THIS WILL LEAD TO GRADUALLY LOWERING HEIGHTS ACROSS THE GREAT LAKES
AND OH VALLEY AND A COLD FRONT DROPPING TOWARD THE REGION TO START
THE WEEKEND. THIS SHOULD BEGIN THE START OF AN UNSETTLED PERIOD.
OVER TIME...A RATHER BROAD TROUGH IS EXPECTED TO DEVELOP FROM CENTRAL
CANADA SOUTH INTO THE ROCKIES AND THEN EAST INTO THE EASTERN CONUS.
MODELS VARY FROM RUN TO RUN AND MODEL TO MODEL WITH THE HANDLING OF
INDIVIDUAL SHORTWAVES IN WEST SOUTH TO SOUTHWEST FLOW DURING THIS
PERIOD AND THE INTERACTION WITH A BAROCLINIC ZONE...THE FRONT THAT
MOVES INTO THE AREA EARLY IN THE WEEKEND...RESULTING IN SFC WAVES
DEVELOPING ALONG THE FRONT. THE ECMWF IS GENERALLY SLOWER BRINGING
THIS FRONT ACROSS THE AREA AND IS ALSO STRONGER AND FURTHER SOUTHEAST
WITH A SFC WAVE SUN NIGHT INTO MONDAY. AS THIS LAST SYSTEM DEPARTS AN
ARCTIC BOUNDARY SHOULD APPROACH THE AREA TUE OR WED.
DUE TO AN OVERALL LACK OF COLDER AIR FOR MOST OF THE PERIOD...MUCH OF
THE PRECIPITATION SHOULD FALL AS RAIN...ALTHOUGH SOME SNOW MAY MIX IN
ON SUNDAY NIGHT INTO EARLY ON MONDAY IN THE HIGHEST TERRAIN AND NORTH
OF THE MTN PARKWAY. A MIX OF RAIN AND SNOW WILL REMAIN POSSIBLE INTO
THE DAY ON TUESDAY AS WE HELD ONTO SLIGHT CHANCE POPS TO ACCOUNT FOR
THE ECMWF RUN. BOTH THE GFS AND ECMWF RUNS SUPPORT A WET END TO THE
WEEKEND.
AS FOR TEMPERATURES...THE PATTERN FAVORS A RIDGE VALLEY TEMPERATURE
SPLIT ON THU NIGHT AS SKIES WILL HAVE CLEARED OR SHOULD BE CLEARING
AS SFC AND UPPER LEVEL RIDGING WORK INTO THE AREA. A RELATIVELY DRY
AIRMASS AND A DOWNSLOPE COMPONENT SHOULD LEAD TO A RATHER MILD DAY ON
FRIDAY...ESPECIALLY FOR VALLEYS NEAR THE VA BORDER. THE DEPARTING
RIDGE SHOULD AGAIN FAVOR MILDER LOWS ON FRI NIGHT...BUT YET ANOTHER
RIDGE/VALLEY SPLIT. SATURDAY SHOULD AGAIN BE MILD AHEAD OF THE
BOUNDARY. WITH THE BAROCLINIC ZONE OVER OR NEAR THE REGION A GENERALLY
NW TO SOUTH OR SOUTHEAST GRADIENT IN TEMPERATURES IS ANTICIPATED FOR
THE REMAINDER OF THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 228 AM EST WED DEC 24 2014
MVFR CIGS HAVE DISSIPATED OVERNIGHT AS DOWNSLOPING FLOW HAS TAKEN
OVER IN THE PRESENT WEAKLY FORCED ENVIRONMENT. ONE MORE ROUND OF
SHOWERS WILL PUSH NORTH LATE TONIGHT INTO THE MORNING HOURS AND MAY
BRING SOME MVFR CIGS AND VISIBILITIES. HOWEVER...AGAIN THIS SHOULD
NOT BE PERSISTENT. A COLD FRONT WILL THEN SURGE EAST ACROSS THE AREA
THIS AFTERNOON AND EVENING...WITH A PERIOD OF GUSTY SOUTHWEST WINDS
ANTICIPATED. THIS MAY ALSO BRING A FEW SHOWERS WITH IT. IN THE WAKE
OF THE FRONT...CIGS SHOULD LOWER BACK TO MVFR AND CONTINUE INTO
TONIGHT...POSSIBLY BORDERING ON IFR CONDITIONS AT TIMES. AFTER A LULL
IN PRECIPITATION INTO THE LATE EVENING HOURS...RAIN WILL REDEVELOP
LATE TONIGHT...WITH SOME SNOW POSSIBLY MIXING IN ABOVE 2500 FEET.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON TODAY TO 10 PM EST THIS EVENING FOR
KYZ044-050>052-058>060-068-069-088-104-106>112-114-118>120.
&&
$$
SHORT TERM...KAS
LONG TERM...JP
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
316 AM EST WED DEC 24 2014
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 316 AM EST WED DEC 24 2014
AREA OF LOW PRESSURE IS NOW STARTING TO MAKE ITS MOVE NORTH ACROSS
CENTRAL KENTUCKY...AND WILL END UP OVER SOUTHEAST MICHIGAN BY THIS
EVENING. STRONG LIFT ASSOCIATED WITH THE LOW PRESSURE SYSTEM WILL
SPREAD ACROSS THE AREA THROUGH DAYBREAK WITH RAIN BECOMING WIDESPREAD
ONCE AGAIN AFTER A BRIEF LULL OVER THE PAST FEW HOURS. HRRR AND RAP
ARE IN GOOD AGREEMENT THAT THIS LIFT WILL EXIT TO THE NORTH BY 9 OR
10 AM...WITH ANOTHER LULL IN PRECIPITATION EXPECTED THROUGH MIDDAY.
WITH THE MIDDAY LULL IN PRECIPITATION...HIGHS WILL WARM INTO THE 60S
FOR ONE MORE DAY.
FINALLY AS THE LOW SHIFTS NORTH THOUGH...A STRONG COLD FRONT WILL
PUSH EAST ACROSS THE AREA THIS AFTERNOON. WITH THE MILD
TEMPERATURES...WE MAY GENERATE SOME WEAK INSTABILITY TO SUPPORT
CONVECTIVE SHOWERS DEVELOPING ALONG THE FRONT AS IT PUSHES ACROSS THE
AREA. WHILE THUNDER CHANCES REMAIN LOW...CANNOT RULE OUT SOME THUNDER
WITH THE STRONGER CELLS...ESPECIALLY ACROSS NORTHERN KENTUCKY. GIVEN
THE ABUNDANCE OF MID LEVEL DRY AIR...AND STRONG 850MB WINDS AROUND 45
KNOTS...WE COULD SEE THE POTENTIAL FOR SOME HIGHER WINDS TO GET MIXED
DOWN WITH THE SHOWERS. HOWEVER...EVEN WITHOUT THE CONVECTIVE SUPPORT
FOR WINDS...THE SYNOPTIC SETUP BEHIND THE FRONT SHOULD SUPPORT 40+
MPH WINDS...ESPECIALLY ACROSS THE NORTHERN HALF OF THE AREA.
THUS...WILL GO AHEAD WITH A WIND ADVISORY FOR THE NORTHERN HALF OF
THE AREA. CONDITIONS ARE MORE MARGINAL FARTHER SOUTH...BUT A WIND
ADVISORY FOR THE HIGH TERRAIN NEAR THE VIRGINIA BORDER ALSO SEEMS IN
ORDER GIVEN THE STRONG WINDS AT 850MB. BEST THREAT FOR THE HIGHER
WINDS WILL BE AFTER 17Z AND BEFORE 03Z TONIGHT.
CONDITIONS WILL QUITE DOWN SOME THIS EVENING AS SUBSIDENCE SPREADS IN
BEHIND THE DEPARTING FRONT. HOWEVER...A SHORTWAVE TROUGH WILL PUSH
EAST ACROSS THE AREA LATE TONIGHT...WITH THE MOISTURE DEPTH
INCREASING TO SUPPORT SOME LIGHT RAIN/DRIZZLE. COLDER AIR WILL ALSO
BE SPILLING INTO THE AREA TONIGHT BEHIND THE FRONT. WHILE MOST AREAS
WILL STAY MILD ENOUGH FOR JUST RAIN...THE HIGHER TERRAIN IN THE
SOUTHEAST WILL SUPPORT SOME SNOW CHANCES. IN FACT...CONDITIONS ALIGN
GOOD ENOUGH TONIGHT WE COULD SEE A LIGHT COATING OF SNOW ON THE HIGH
TERRAIN ABOVE 2500 FEET LATE TONIGHT.
HEIGHTS WILL BE QUICK TO BUILD BACK ACROSS THE AREA ON CHRISTMAS.
CLOUDS MAY BE STUBBORN THROUGH THE FIRST HALF OF THE DAY...BUT WE
SHOULD DEFINITELY SEE A DECREASING TREND THROUGH THE AFTERNOON AND
EVENING AS THE RIDGE CENTERS ITSELF OVER THE REGION. HIGHS WILL
STRUGGLE TO WARM GIVEN THE ABUNDANCE OF CLOUDS THROUGH THE FIRST HALF
OF THE DAY...SO PLAN TO KEEP HIGHS LIMITED TO THE LOW TO MID 40S WITH
30S ON THE HIGHER TERRAIN IN THE SOUTHEAST.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 316 AM EST WED DEC 24 2014
LONG TERM DISCUSSION WILL FOLLOW SHORTLY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 228 AM EST WED DEC 24 2014
MVFR CIGS HAVE DISSIPATED OVERNIGHT AS DOWNSLOPING FLOW HAS TAKEN
OVER IN THE PRESENT WEAKLY FORCED ENVIRONMENT. ONE MORE ROUND OF
SHOWERS WILL PUSH NORTH LATE TONIGHT INTO THE MORNING HOURS AND MAY
BRING SOME MVFR CIGS AND VISIBILITIES. HOWEVER...AGAIN THIS SHOULD
NOT BE PERSISTENT. A COLD FRONT WILL THEN SURGE EAST ACROSS THE AREA
THIS AFTERNOON AND EVENING...WITH A PERIOD OF GUSTY SOUTHWEST WINDS
ANTICIPATED. THIS MAY ALSO BRING A FEW SHOWERS WITH IT. IN THE WAKE
OF THE FRONT...CIGS SHOULD LOWER BACK TO MVFR AND CONTINUE INTO
TONIGHT...POSSIBLY BORDERING ON IFR CONDITIONS AT TIMES. AFTER A LULL
IN PRECIPITATION INTO THE LATE EVENING HOURS...RAIN WILL REDEVELOP
LATE TONIGHT...WITH SOME SNOW POSSIBLY MIXING IN ABOVE 2500 FEET.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON TODAY TO 10 PM EST THIS EVENING FOR
KYZ044-050>052-058>060-068-069-088-104-106>112-114-118>120.
&&
$$
SHORT TERM...KAS
LONG TERM...JP
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
228 AM EST WED DEC 24 2014
.UPDATE...
ISSUED AT 228 AM EST WED DEC 24 2014
UPDATED TO REFINE POPS THROUGH THE REMAINDER OF THE NIGHT. IT LOOKS
LIKE ONE MORE BETTER SURGE OF MOISTURE WILL PUSH ACROSS THE AREA
STARTING FROM THE SOUTH AROUND 10Z...THEN PUSH NORTHWARD THROUGH THE
EARLY MORNING HOURS. THIS TIME AROUND IT SHOULD NOT PERSIST AS LONG
AND WE MAY ACTUALLY SEE A PRETTY GOOD BREAK FROM PRECIPITATION BY MID
MORNING...BEFORE THE COLD FRONT PUSHES EAST ACROSS THE AREA IN THE
AFTERNOON...BRINGING THE THREAT OF SCATTERED SHOWERS BACK TO THE
AREA.
UPDATE ISSUED AT 1116 PM EST TUE DEC 23 2014
LIGHTNING IN OUR AREA ENDED EARLY IN THE EVENING...WITH CONVECTIVE
SYSTEMS DOMINATING OVER THE DEEP SOUTH. THE NAM IS SUGGESTING A
RESURGENCE OF INSTABILITY MOVING IN FROM THE SW ON WEDNESDAY MORNING
AS LOW PRESSURE MOVES NORTH THROUGH CENTRAL KY AND ITS TRAILING COLD
FRONT APPROACHES. HAVE REMOVED THUNDER FOR TONIGHT...BUT KEPT A
POTENTIAL ON WEDNESDAY AHEAD OF THE FRONT.
UPDATE ISSUED AT 618 PM EST TUE DEC 23 2014
WIDESPREAD PRECIP HAS OCCURRED MOST OF THE FORECAST AREA...WITH THE
EXCEPTION OF THE FAR EAST. RAIN WILL CONTINUE AND SHOULD EVENTUALLY
AFFECT EVEN THE EASTERN PART OF THE AREA TONIGHT. PREVIOUS FORECAST
OF CATEGORICAL POPS STILL LOOKS ON TRACK. HAVE UPDATED TEMPS BASED ON
LATEST OBS AND MODEL DATA...BUT OVERALL THE CHANGES WERE MINIMAL.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 353 PM EST TUE DEC 23 2014
THIS AFTERNOON SHOWERS AND THUNDERSTORMS ARE SPREADING ACROSS
PORTIONS OF EASTERN KY. WSR-88D SHOWING BEST CONCENTRATION OF SHOWERS
AND THUNDERSTORMS GENERALLY ALONG AND JUST EAST OF THE WESTERN CWA
BORDER. SHOWERS HAVE BEEN MOVING NE ALONG THIS AREA WITH SOME AREAS
SEEING AROUND A QUARTER OF A INCH WITH HIGHER AMTS POSSIBLE IN
HEAVIER STORMS. HRRR GUIDANCE SEEMS TO HAVE A DECENT HANDLE ON THESE
BANDS OF SHOWERS AND THUNDERSTORMS AND HAS THESE BANDS ACROSS
PORTIONS OF THE TN VALLEY PROGRESSING NORTH ACROSS EASTERN KY THIS
EVENING INTO TONIGHT. 18Z SURFACE ANALYSIS SHOWS LOW PRESSURE
CONTINUING TO DEVELOP ALONG THE LA COAST LINE THIS AFTERNOON. THIS
AREA OF LOW PRESSURE IS EXPECTED TO CONTINUE TO MOVE NORTH AND EAST
OVERNIGHT INTO WEDNESDAY. THIS WILL CONTINUE TO SPREAD RAIN ACROSS
THE REGION. THIS SURFACE LOW WILL ALSO BRING A STRONG COLD FRONT
ACROSS EASTERN KY TOMORROW AFTERNOON THIS WILL PROVIDE GOOD LIFTING
MECHANISM FOR SHOWERS AND THUNDERSTORMS WITH GUSTY WINDS POSSIBLE.
BEHIND THIS FRONT WOULD EXPECT THERE TO CONTINUE TO BE GUSTY WINDS
PARTICULARLY ACROSS THE HIGHER TERRAIN AND NW PORTIONS OF THE CWA.
MOVING INTO WEDNESDAY NIGHT LOW PRESSURE IS FORECAST TO MOVE NORTH
INTO THE GREAT LAKES REGION AND WE WILL QUICKLY GET INTO THE DRY
SLOT. THEREFORE MOISTURE DOES GET CUTOFF AND LOOKING AT FORECAST
SOUNDINGS THIS WOULD LEAD TO LITTLE IF ANY ICE ALOFT. DID OPT TO KEEP
A SLIGHT CHANCE OF RAIN MIXED WITH SNOW AND MAYBE SOME DRIZZLE ACROSS
THE HIGHER TERRAIN...HOWEVER CONFIDENCE IN ANY SNOW CONTINUES TO
DECREASE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 429 PM EST TUE DEC 23 2014
THE MODELS ARE GENERALLY IN GOOD AGREEMENT WITH AN AMPLIFIED LONG
WAVE PATTERN TO CONTINUE THROUGH THE PERIOD ACROSS THE CONUS. MODEL
DIFFERENCES CONTINUE HOWEVER TOWARDS THE LATTER HALF OF THE
PERIOD...AND HAVE SIDED MORE WITH THE ECMWF/CANADIAN SOLUTION GIVEN
THE OVERALL BETTER CONTINUITY.
DEEPER TROUGHING WILL BE MOVING OFF TO THE EAST ON THURSDAY...WITH
ANY LIGHT PRECIPITATION COMING TO AN END ACROSS EASTERN KENTUCKY BY
THE MORNING HOURS. DRY WEATHER WILL RETURN FROM THURSDAY AFTERNOON
THROUGH EARLY SATURDAY MORNING...AS RIDGING TAKES HOLD ACROSS THE
OHIO AND TENNESSEE VALLEYS. MEANWHILE...TROUGHING WILL BE REASSERT
ITSELF ACROSS THE ROCKIES...WITH A COLD FRONT MOVING INTO THE AREA
FOR THE WEEKEND.
THE GFS REMAINS PROGRESSIVE WITH THIS BOUNDARY...WHILE THE
ECMWF/CANADIAN ARE SLOWER AND ALLOW FOR MORE SOUTHERN STREAM
INTERACTION...PROLONGING THE PRECIPITATION CHANCES ALL THE WAY INTO
EARLY NEXT WEEK. AGAIN...AM INCLINED TO LEAN TOWARDS THE
ECMWF/CANADIAN SOLUTION AS THE GFS HAS TRENDED MORE AMPLIFIED WITH
THE UPPER LEVEL PATTERN FROM 24 HOURS AGO. AS SUCH...HAVE FOLLOWED
SUIT WITH THE GIVEN BLENDED GUIDANCE AND ALLOWED FOR LIKELY POPS
BY SUNDAY...AND THEN LOWER CHANCES INTO EARLY NEXT UNTIL SOME OF THE
DETAILS CAN BE IRONED OUT. THE FORECAST TEMPERATURE PROFILES SUPPORT
MORE RAIN THEN SNOW THROUGH WEEKEND...AND THEN PERHAPS A SNOWIER
FINISH AS WE HEAD INTO TUESDAY DEPENDING HOW MUCH COLDER AIR ACTUALLY
MAKES IT IN.
FOR TEMPERATURES...GENERALLY ABOVE NORMAL READINGS LOOK ON TAP
THROUGH THE WEEKEND...WITH NEAR TO COOLER THAN NORMAL VALUES BY EARLY
NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 228 AM EST WED DEC 24 2014
MVFR CIGS HAVE DISSIPATED OVERNIGHT AS DOWNSLOPING FLOW HAS TAKEN
OVER IN THE PRESENT WEAKLY FORCED ENVIRONMENT. ONE MORE ROUND OF
SHOWERS WILL PUSH NORTH LATE TONIGHT INTO THE MORNING HOURS AND MAY
BRING SOME MVFR CIGS AND VISIBILITIES. HOWEVER...AGAIN THIS SHOULD
NOT BE PERSISTENT. A COLD FRONT WILL THEN SURGE EAST ACROSS THE AREA
THIS AFTERNOON AND EVENING...WITH A PERIOD OF GUSTY SOUTHWEST WINDS
ANTICIPATED. THIS MAY ALSO BRING A FEW SHOWERS WITH IT. IN THE WAKE
OF THE FRONT...CIGS SHOULD LOWER BACK TO MVFR AND CONTINUE INTO
TONIGHT...POSSIBLY BORDERING ON IFR CONDITIONS AT TIMES. AFTER A LULL
IN PRECIPITATION INTO THE LATE EVENING HOURS...RAIN WILL REDEVELOP
LATE TONIGHT...WITH SOME SNOW POSSIBLY MIXING IN ABOVE 2500 FEET.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...DJ
LONG TERM...GEOGERIAN
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
1116 PM EST TUE DEC 23 2014
.UPDATE...
ISSUED AT 1116 PM EST TUE DEC 23 2014
LIGHTNING IN OUR AREA ENDED EARLY IN THE EVENING...WITH CONVECTIVE
SYSTEMS DOMINATING OVER THE DEEP SOUTH. THE NAM IS SUGGESTING A
RESURGENCE OF INSTABILITY MOVING IN FROM THE SW ON WEDNESDAY MORNING
AS LOW PRESSURE MOVES NORTH THROUGH CENTRAL KY AND ITS TRAILING COLD
FRONT APPROACHES. HAVE REMOVED THUNDER FOR TONIGHT...BUT KEPT A
POTENTIAL ON WEDNESDAY AHEAD OF THE FRONT.
UPDATE ISSUED AT 618 PM EST TUE DEC 23 2014
WIDESPREAD PRECIP HAS OCCURRED MOST OF THE FORECAST AREA...WITH THE
EXCEPTION OF THE FAR EAST. RAIN WILL CONTINUE AND SHOULD EVENTUALLY
AFFECT EVEN THE EASTERN PART OF THE AREA TONIGHT. PREVIOUS FORECAST
OF CATEGORICAL POPS STILL LOOKS ON TRACK. HAVE UPDATED TEMPS BASED ON
LATEST OBS AND MODEL DATA...BUT OVERALL THE CHANGES WERE MINIMAL.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 353 PM EST TUE DEC 23 2014
THIS AFTERNOON SHOWERS AND THUNDERSTORMS ARE SPREADING ACROSS
PORTIONS OF EASTERN KY. WSR-88D SHOWING BEST CONCENTRATION OF SHOWERS
AND THUNDERSTORMS GENERALLY ALONG AND JUST EAST OF THE WESTERN CWA
BORDER. SHOWERS HAVE BEEN MOVING NE ALONG THIS AREA WITH SOME AREAS
SEEING AROUND A QUARTER OF A INCH WITH HIGHER AMTS POSSIBLE IN
HEAVIER STORMS. HRRR GUIDANCE SEEMS TO HAVE A DECENT HANDLE ON THESE
BANDS OF SHOWERS AND THUNDERSTORMS AND HAS THESE BANDS ACROSS
PORTIONS OF THE TN VALLEY PROGRESSING NORTH ACROSS EASTERN KY THIS
EVENING INTO TONIGHT. 18Z SURFACE ANALYSIS SHOWS LOW PRESSURE
CONTINUING TO DEVELOP ALONG THE LA COAST LINE THIS AFTERNOON. THIS
AREA OF LOW PRESSURE IS EXPECTED TO CONTINUE TO MOVE NORTH AND EAST
OVERNIGHT INTO WEDNESDAY. THIS WILL CONTINUE TO SPREAD RAIN ACROSS
THE REGION. THIS SURFACE LOW WILL ALSO BRING A STRONG COLD FRONT
ACROSS EASTERN KY TOMORROW AFTERNOON THIS WILL PROVIDE GOOD LIFTING
MECHANISM FOR SHOWERS AND THUNDERSTORMS WITH GUSTY WINDS POSSIBLE.
BEHIND THIS FRONT WOULD EXPECT THERE TO CONTINUE TO BE GUSTY WINDS
PARTICULARLY ACROSS THE HIGHER TERRAIN AND NW PORTIONS OF THE CWA.
MOVING INTO WEDNESDAY NIGHT LOW PRESSURE IS FORECAST TO MOVE NORTH
INTO THE GREAT LAKES REGION AND WE WILL QUICKLY GET INTO THE DRY
SLOT. THEREFORE MOISTURE DOES GET CUTOFF AND LOOKING AT FORECAST
SOUNDINGS THIS WOULD LEAD TO LITTLE IF ANY ICE ALOFT. DID OPT TO KEEP
A SLIGHT CHANCE OF RAIN MIXED WITH SNOW AND MAYBE SOME DRIZZLE ACROSS
THE HIGHER TERRAIN...HOWEVER CONFIDENCE IN ANY SNOW CONTINUES TO
DECREASE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 429 PM EST TUE DEC 23 2014
THE MODELS ARE GENERALLY IN GOOD AGREEMENT WITH AN AMPLIFIED LONG
WAVE PATTERN TO CONTINUE THROUGH THE PERIOD ACROSS THE CONUS. MODEL
DIFFERENCES CONTINUE HOWEVER TOWARDS THE LATTER HALF OF THE
PERIOD...AND HAVE SIDED MORE WITH THE ECMWF/CANADIAN SOLUTION GIVEN
THE OVERALL BETTER CONTINUITY.
DEEPER TROUGHING WILL BE MOVING OFF TO THE EAST ON THURSDAY...WITH
ANY LIGHT PRECIPITATION COMING TO AN END ACROSS EASTERN KENTUCKY BY
THE MORNING HOURS. DRY WEATHER WILL RETURN FROM THURSDAY AFTERNOON
THROUGH EARLY SATURDAY MORNING...AS RIDGING TAKES HOLD ACROSS THE
OHIO AND TENNESSEE VALLEYS. MEANWHILE...TROUGHING WILL BE REASSERT
ITSELF ACROSS THE ROCKIES...WITH A COLD FRONT MOVING INTO THE AREA
FOR THE WEEKEND.
THE GFS REMAINS PROGRESSIVE WITH THIS BOUNDARY...WHILE THE
ECMWF/CANADIAN ARE SLOWER AND ALLOW FOR MORE SOUTHERN STREAM
INTERACTION...PROLONGING THE PRECIPITATION CHANCES ALL THE WAY INTO
EARLY NEXT WEEK. AGAIN...AM INCLINED TO LEAN TOWARDS THE
ECMWF/CANADIAN SOLUTION AS THE GFS HAS TRENDED MORE AMPLIFIED WITH
THE UPPER LEVEL PATTERN FROM 24 HOURS AGO. AS SUCH...HAVE FOLLOWED
SUIT WITH THE GIVEN BLENDED GUIDANCE AND ALLOWED FOR LIKELY POPS
BY SUNDAY...AND THEN LOWER CHANCES INTO EARLY NEXT UNTIL SOME OF THE
DETAILS CAN BE IRONED OUT. THE FORECAST TEMPERATURE PROFILES SUPPORT
MORE RAIN THEN SNOW THROUGH WEEKEND...AND THEN PERHAPS A SNOWIER
FINISH AS WE HEAD INTO TUESDAY DEPENDING HOW MUCH COLDER AIR ACTUALLY
MAKES IT IN.
FOR TEMPERATURES...GENERALLY ABOVE NORMAL READINGS LOOK ON TAP
THROUGH THE WEEKEND...WITH NEAR TO COOLER THAN NORMAL VALUES BY EARLY
NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 813 PM EST TUE DEC 23 2014
ALTHOUGH RAIN WAS FALLING AT MOST LOCATIONS...CONDITIONS WERE MAINLY
VFR OVER ALL BUT THE SW AND FAR WESTERN PORTIONS OF THE JKL FORECAST
AREA AT THE START OF THE PERIOD...WITH DOWNSLOPE FLOW FROM THE SOUTH
SOUTHEAST HELPING TO MITIGATE LOW CLOUDS AND FOG. MVFR VISIBILITY WAS
COMMON FROM MIDDLESBORO AND LONDON WESTWARD. ALTHOUGH SOME
FLUCTUATIONS CAN BE EXPECTED TONIGHT...THIS GENERAL SCENARIO SHOULD
CONTINUE. DURING THE DAY ON WEDNESDAY A COLD FRONT WILL MOVE IN FROM
THE WEST AND BRING A POTENTIAL INCREASE IN SHOWER INTENSITY BEFORE IT
PASSES...WITH A RISK OF THUNDERSTORMS TOO. AS THE FRONT PASSES...
WINDS WILL VEER TOWARD THE SW AND THE DOWNSLOPE COMPONENT WILL BE
LOST. AS THIS HAPPENS...CEILINGS SHOULD DROP TO MVFR AND IFR.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...DJ
LONG TERM...GEOGERIAN
AVIATION...HAL
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1151 PM CST Tue Dec 23 2014
.UPDATE:
Issued at 821 PM CST Tue Dec 23 2014
Digesting the 00Z NAM and HRRR runs and combined they continue to
support the going forecast with a band of rain developing
overnight along and east of the Mississippi River, then mixing/changing
to snow from west to east during the morning hours. Accumulation
will be most likely under the heaviest and most persistent band of
snow which looks to roughly align from KBLV to KTAZ. Only minor
changes were made to the forecast as the placement of the
mesoscale snowband and final adjustments to the forecast will be
a nowcasting exercise by the next shift.
Issued at 650 PM CST Tue Dec 23 2014
Quick update this evening to lower POPs, as it appears that other
than some areas of drizzle across southwest Illinois, the better
shower activity will not develop until after midnight. Still
appears that the majority of the precipitation should fall as rain
tonight, perhaps mixing with snow very late on the western fringe
of the precipitation that develops overnight.
Hope to have another update out by 10 PM after some of the 00Z
model guidance arrives regarding any changes needed to the
snowfall forecast for tomorrow.
CVKING
&&
.SHORT TERM: (Tonight through Wednesday Night)
Issued at 251 PM CST Tue Dec 23 2014
The main forecast issue remains the impending storm system and
potential for accumulating snowfall. The models have come into
much better agreement with mass fields than they exhibited 24
hours ago. Yet, there are still some large issues with thermal
fields, qpf, and speed of the system that are resulting in lower
than normal confidence and higher than normal uncertainty.
The overall scenario is unchanged. The upper low is in the
development process within the southern portion of the deep
positively tilted trof across OK. The guidance is fairly well
clustered lifting the upper low northeast into southwest MO by
daybreak Wednesday to near St. Louis at 18z and into the lower
Great Lakes region by 00z. In response the surface low currently
located along the front in LA will deepen and move through the TN
and OH Vallies over the next 24 hours. Initially the warm conveyor
belt and mid level frontogenetical forcing will be the key players,
with rain presently across AR increasing in coverage and spreading
northeast into southeast Missouri this evening and northeastward
into far east central MO and southwest IL overnight. Model consensus
indicates the thermal profiles should begin cooling sufficiently
on the western fringe of the rain shield after 09z for the rain to
mix and begin changing to snow. After 12z Wednesday the large
scale forcing/ascent really ramps up in association with the
ejecting mid/upper low and this should result in an upswing in
coverage and intensity of precipitation from east central MO into
south central and central IL, and accelerated changeover to snow.
All of the CWA should be entirely snow by 18z, as the deformation
zone precipitation begins shifting away from the CWA. Snow amounts
are still a tough call and there is lots of room for error. The
mean track of the H85 low would place the most-favored axis of
highest precipitation from around Belleville to Decatur, but
during some of the time the rain will be changing to snow. Also
surface temperatures will be in the 32-35F range and SLRs are
expected to be lower than normal with a wet snow expected. The new
forecast has the highest amounts along the aforementioned corridor
with a general 2-3 inches. I wouldn`t be surprised to see locally higher
totals, especially as you head northeastward into central IL.
Given potential the impacts of slushy/slippery roads and reduced
visibility on holiday travel, we have gone ahead an issued a winter
weather advisory even though these amounts are generally below
those we typically consider for an advisory.
Some residual non-accumulating light snow/flurries may linger from
east central MO into IL during the first part of the evening,
however this will be a short window. The system continues its
quick departure with ridging aloft already by 12z Thursday and low
level warm advection underway after 06z.
Glass
.LONG TERM: (Thursday through Next Tuesday)
Issued at 251 PM CST Tue Dec 23 2014
Pronounced warm advection and backing flow aloft in response to
new upstream amplification will dominate Christmas day. The snow
cover will likely be short-lived as temperatures moderate above
normal Thursday into Friday.
A deep and slow progressive long wave trof will then dominate the
upper air pattern into the weekend featuring separate northern and
southern stream components. Present indications are we should see
a cold front passage on Friday night with an attendant threat of
precipitation. An overrunning pattern could then set-up Saturday
into Sunday with snow possible in the deeper cold air, however the
models are quite variable in their depictions of the important features.
Glass
&&
.AVIATION: (For the 06z TAFs through 06z Wednesday Night)
Issued at 1124 PM CST Tue Dec 23 2014
Tricky low confidence fcst for Wed. A cold front has pushed thru
all the terminals this evng. CIGs should slowly lower to IFR by
Wed mrng and then remain in place thru the end of the fcst prd. An
upper lvl disturbance will force a sfc low across the deep south
to strengthen overnight as it moves to the ern Grt Lks by tomorrow
evng. An area of precip will dvlp and move towards the STL metro
area late tonight. There is some uncertainty about how far west
the precip shield will extend. Current guidance indicates that the
precip should mix with and potentially change over to snow for a
few hours Wed mrng, though new model solutions this evng are
beginning to trend away from this scenario. There is some question
about when or where the changeover to snow will occur. It is
possible that KSUS may not see much precip at all while KCPS has
accumulating snow during the late mrng into early aftn. Am not
confident that any terminal in the STL metro area will see snow.
If that occurs, then VSBYs are too low. Am not inclined to change
the fcst until the precip dvlps. There is another upper lvl
disturbance that will track into cntrl MO Wed mrng and then push
east thru the aftn producing some addtnl VFR -RASN. Any precip
should come to an end by evng.
Specifics for KSTL:
An area of precip is expected to dvlp south of the area and move
north into the terminal prior to sunrise. Precip is expected to mix
with and potentially switch over to all snow during the late mrng.
Am not confident in this scenario as new model guidance this evng
has trended away from this solution but, am inclined to leave the
basic details intact until the precip dvlps and details become
better defined. If the switch over to snow does not occur then
VSBYs are too low tomorrow aftn. The main precip shield should
lift north of the terminal by early aftn. Occnl VFR -RASN should
continue thru the remainder of the aftn in the wake of this system
and as another upper level disturbance approaches from cntrl MO.
IFR CIGs should hang tough thru 6Z.
2%
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY from 6 AM to 6 PM CST Wednesday FOR
Jefferson MO-St. Charles MO-St. Louis City MO-St. Louis MO.
IL...WINTER WEATHER ADVISORY from 6 AM to 6 PM CST Wednesday FOR Bond
IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-Macoupin IL-
Madison IL-Marion IL-Monroe IL-Montgomery IL-St. Clair IL-
Washington IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1131 PM CST TUE DEC 23 2014
.UPDATE...
ISSUED AT 1124 PM CST TUE DEC 23 2014
PERSISTENT DEFORMATION-BAND PRECIPITATION HAS BEEN SHOWING SIGNS
OF DECREASING IN INTENSITY AND AREAL COVERAGE OVER THE LAST COUPLE
OF HOURS...BUT RADAR RETURNS CONTINUE TO FLARE UP FROM TIME TO
TIME ACROSS WESTERN IOWA AND ROTATE INTO EASTERN NEBRASKA. EXPECT
THIS TREND TO CONTINUE FOR SEVERAL HOURS PAST MIDNIGHT. HOWEVER
TEMPERATURES REMAIN ABOVE FREEZING IN PRECIP AREAS...SO ANY
SNOWFALL SHOULD REMAIN MINIMAL. OTHERWISE NORTHWEST WINDS GUSTING
OVER 20 MPH WILL HELP TO DRY OUT ROADS OVERNIGHT...BUT COULD STILL
SEE A FEW SLICK SPOTS IN THE MORNING AS TEMPERATURES DROP BELOW
FREEZING.
&&
.SHORT TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 300 PM CST TUE DEC 23 2014
BAND OF GENERALLY LIGHT MIXED PRECIP CONTINUES TO TRACK SLOWLY
SOUTH ACROSS SOUTHEAST NEBRASKA AND SOUTHWEST IOWA AT 20Z. THIS
TREND IS EXPECTED TO CONTINUE INTO THE EVENING AS UPPER TROUGH
MOVES SLOWLY EAST. TEMPERATURES ARE IN THE MID TO UPPER 30S SO
WHATEVER SNOW DOES FALL MELTS FAIRLY QUICKLY. NDOR WEB CAMS SHOW
LITTLE TO NO SNOW COVER SOUTH OF A COLUMBUS TO TEKAMAH LINE.
LATEST RAP MODEL INDICATES A DIMINISHING TREND TO THE PRECIP THIS
EVENING WITH ONLY MINOR ACCUMULATIONS EXPECTED AS TEMPERATURES
FALL TO NEAR 32 THROUGH 06Z. STRONGER DYNAMICS SHIFT WELL EAST OF
THE AREA TONIGHT TO THE TENNESSEE AND LOWER OHIO VALLEY WITH
SHORT WAVE RIDGING BUILDING INTO THE NORTHERN PLAINS.
FORECAST SOUNDINGS SUGGEST DECREASING CLOUDS ACROSS THE AREA FOR
WEDNESDAY ALTHOUGH EASTERN AREAS MAY BE LIMITED TO LATE AFTERNOON
FOR ANY POTENTIAL VIEWING OF SUNSHINE. CLEARING TREND CONTINUES
WEDNESDAY NIGHT INTO THURSDAY BEFORE CLOUDS INCREASE ONCE AGAIN
THURSDAY NIGHT AND FRIDAY BEHIND THE NEXT COLD FRONT AND
APPROACHING UPPER TROUGH. SOME LIGHT SNOW IS LIKELY AGAIN WITH
THIS SYSTEM ON FRIDAY BUT NO MAJOR IMPACT ON TRAVEL IS EXPECTED.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 300 PM CST TUE DEC 23 2014
SNOW MAY LINGER INTO FRIDAY NIGHT FOR SOUTHERN PARTS OF THE AREA
THEN DRY BUT COLD FOR THE WEEKEND. STRONG TROUGHING DEVELOPS OVER
THE CENTRAL PART OF THE NATION EARLY NEXT WEEK WITH MUCH COLDER
AIR ON TAP FOR THE END OF THE YEAR.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1124 PM CST TUE DEC 23 2014
MVFR CIGS WILL BE THE RULE THROUGH AT LEAST MID AFTERNOON AT
EASTERN AFTERNOON TAF SITES BEFORE WESTERLY WINDS BEGIN TO DRY LOW
LEVELS FROM WEST TO EAST. KLNK AND KOMA COULD SEE A BRIEF IFR
CIG/VSBY THROUGH ABOUT 10Z WHEN RAIN OR SNOW MOVES OVER THOSE
SITES. PRECIPITATION SHOULD BE EAST OF ALL TAF SITES BEFORE 12Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
UPDATE...DERGAN
SHORT TERM...FOBERT
LONG TERM...FOBERT
AVIATION...DERGAN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
156 AM EST WED DEC 24 2014
.SYNOPSIS...
A STORM SYSTEM OVER THE EASTERN GREAT LAKES WILL BRING RAIN TO
OUR REGION INTO WEDNESDAY NIGHT. A COLD FRONT EARLY CHRISTMAS
MORNING WILL BRING RAIN SHOWERS AND EVEN A FEW THUNDERSTORMS WITH
GUSTY WINDS. IT WILL BE WINDY AND CHILLY FOR THE REMAINDER OF
CHRISTMAS DAY WITH A CHANCE OF RAIN AND SNOW SHOWERS. A RIDGE OF
HIGH PRESSURE WILL BRING FAIR WEATHER TO OUR REGION ON FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
940 PM UPDATE...
CHANGED POP GRIDS OVERNIGHT TO REFLECT THE RAIN ADVANCING INTO THE
FA FROM THE WEST BETWEEN 7Z AND 11Z. STUCK TO CATEGORICAL POPS FOR
THE EARLY MORNING HOURS ONCE THE RAIN GETS ESTABLISHED NEAR SUNRISE.
ALSO REWORKED THE TEMPERATURE GRIDS AS IT APPEARS WE HAVE ALREADY
SEEN OUR MINS FOR THE NIGHT. TEMPERATURES ARE HOLDING STEADY OR
RISING ATTM. USING A BLEND OF THE HRRR AND LAMP, WE CAME UP WITH A
REALISTIC LOOKING HOURLY TEMPERATURE PROG FOR THE OVERNIGHT. THE
RAP INITIALIZED WAY TOO COLD AT THE SURFACE OVER THE EAST, SO WE
THREW IT OUT THIS RUN.
130 PM UPDATE...
RADARS SHOW AN AREA OF RAIN ACROSS NC AND ERN NY AND THE LATEST
HRRR HAS DONE A DECENT JOB OF SIMULATING THIS. THIS PRECIPITATION
WAS ASSCTD WITH A SHORT WAVE THAT WAS MAKING ITS WAY INTO NEW
ENGLAND. THE HRRR ADVECTS THIS RAIN EASTWARD BY 20-21Z W/ NE PA
AND C NY CONTINUING UNDER A VERY MOIST SERLY LOW-LEVEL FLO. THIS
MOIST FLO WILL CONT PATCHY AREAS OF LIGHT RAIN AND DRIZZLE INTO
THE EVENING AND OVERNIGHT HOURS AS OUR AREA WILL BE IN A LULL IN
THE HEAVIER RAINS. A MUCH MORE SIGNIFICANT AND LARGER PRECIPITATION
SHIELD WILL ARRIVE BTWN ABT 9 AND 12Z WED FROM S TO N ACRS NE PA/C
NY. THE DYNAMICS AND MOISTURE TRANSPORT WERE FAIRLY IMPRESSIVE
FOR WED/WED EVE.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS A LARGE UPPER LEVEL
WAVE PRESENTLY OVER TEXAS MOVING INTO THE BASE OF A LONG WAVE
TROF. THE DYNAMIC TROPOPAUSE WAS DOWN TO ABT 530 MB WITH THIS
FEATURE. THIS WAVE WILL RIDE NE UP THRU THE MIDWEST WEDNESDAY AND
CLOSE OFF TO A 500 MB LOW BY 00Z THU OVER LWR MI. AS THIS OCCURS
OUR AREA COMES UNDER DEEP UPPER LEVEL DVRG AND AN ACCELERATING
S-SWRLY LOW-LEVEL FLOW WHICH PEAKS AT ABT 50 KNOTS AT 850 MB WED
AFTERNOON AND EVENING. ALL THE SYNOPTIC SCALE MODELS INDICATE A
MAX IN QPF EAST OF A LINE FROM ABT AVP TO ALB. THE FINGER LAKES
REGION TO WRN NY IS IN A LOCAL MINIMUM ON ALL SYNOPTIC MODELS
INCLUDING 12Z EURO...12Z GFS...12Z NAM AND 12Z CMC. THIS MAKES
SENSE AS THE LL FLOW IS S-SWRLY AND THE LLJ WHICH FOCUSES MOISTURE
AND PRECIPITATION WILL BE SPLIT BY THE APPLCNS. THE EURO...GFS AND
CMC ALL AGREE THAT THE MAXIMUM QPF IS BTWN 1 AND 1.5 INCHES MAINLY
ACRS AREAS E OF A LINE FROM AVP TO DELAWARE CO NY IN OUR FORECAST
AREA WITH .25 TO .5 INCHES QPF IN THE FINGER LAKES. THE NAM IS
HEAVY HANDED WITH THE QPF AND HAS OVER 2 INCHES IN OUR FAR ERN
ZONES AND .5 INCHES IN THE FINGER LAKES. ONLY LOCALLY CUD I SEE 2
INCHES IN THE CATSKILLS AND POCONOS...BUT NOT WIDESPREAD ENUF TO
CAUSE SIGNIFICANT HYDRO ISSUES. SNOWPACK WAS MINIMAL IN THESE
AREAS SO WE ARE EXPECTING RISES TO AT LEAST 1/2 TO 3/4 BANKFUL
ON MANY RIVERS AND TRIBUARTIES BUT NO FLOOD ISSUES OF SIGNIFICANCE
OTHER THAN URBAN FLOODING. SO NO FLOOD WATCH AT THIS TIME. PRECIP
WILL CONTINUE INTO WED EVE OFF AND ON. TEMPERATURES WILL HOLD
STEADY AND SLOWLY RISE THRU WEDNESDAY.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
FOR WEDNESDAY NIGHT...MAIN CONCERN IS THE POTENTIAL FOR A QLCS OR
NARROW COLD FRONTAL RAIN BAND ALONG THE COLD FRONT WHICH SWINGS
THRU THE REGION BY 4-8Z THU. TIMING OF THIS FRONT IS STILL UNCERTAIN
BUT IT APPEARS IT WILL COME THRU JUST AFTER MIDNIGHT OR SO. THE
DYNAMICS ARE VERY IMPRESSIVE AS ALL SYNOPTIC MODELS SHOW A STRG
UPPER LEVEL PV MAX SWINGING THRU WITH SRG DVRG ALOFT ERLY THU AM.
THE LOW TO MID LEVEL WINDS AT FROPA WERE VERY STRG WITH 0-1 KM
BULK SHEAR AT 45 KNOTS, 0-3 KM ARND 50-60 KNOTS AND 0-6 KM FROM 80
TO 100 KNOTS DEPENDING ON THE MODEL. 0-1 KM HELICITIES WERE
PROGGED CLOSE TO 300 M2/S2. CAPES WERE MARGINAL WHICH IS TO BE
EXPECTED... RUNNING POTENTIALLY UP TO 250 J/KG OR SO MAINLY IN OUR
ERN ZONES. DEWPOINTS ARE PROJECTED TO CLIMB ABV 50F IN THE SRLY
FLOW...ESPECIALLY ACRS NE PA TO EC NY. MODELS SHOW THAT THE DWPTS
AT 850 MB CLIMB ABV 10C WHICH IS 50F AS WELL ACRS ENTIRE AREA. WE
RAN OUR LOCAL SVR WX ANALOG CHECKLIST WHICH COMPARES FORECAST
PARAMETERS WITH HISTORICAL EVENTS AND IT RETURNED 4 OUT OF 5
EVENTS THAT HAD SIGNIFICANT WIND DAMAGE. 3 OF THE 5 EVENTS HAD
ISOLATED TORNADOES INCLUDING THE F2 OF DEC 2006 WHICH HIT NE PA.
FOR NOW HAVE MENTION OF THUNDERSTORMS WITH GUSTY WINDS IN GRIDS
WED NGT/ERLY THU. WILL HIGHLIGHT POTENTIAL FOR STRONG TO LOCALLY
SEVERE THUNDERSTORMS IN THE HWO AS SPC HAS SOME OF OUR AREA IN A
MARGINAL RISK.
AFTER FROPA ON CHRISTMAS DAY...IT WILL BE WINDY WITH PRESSURE
RISES OF ABT 10 TO 15 MB / 12 HOURS IN C NY WHICH IS CLOSE TO
ADVY CRITERIA. WILL MENTION POTENTIAL FOR WIND GUSTS TO 50 MPH IN
HWO FOR C NY...MAINLY FINGER LAKES REGION TO SYR/RME AREAS. THERE
WILL ALSO BE SCT RAIN AND SNOW SHOWERS ARND IN THE BACKLASH OF
THIS LARGE CYCLONE WHICH TAPERS OFF THU NGT.
FRIDAY WILL BE FAIR AND STILL MILD AS A RDG OF HIGH PRESSUIE
BUILDS ACRS THE REGION AS HGHTS RAPIDLY RISE.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
130 AM UPDATE...
LITTLE CHANGE. WPC GUIDANCE FOLLOWED THE SAME TUNE. TRICKY PART
WILL BE LOW LEVEL TEMPERATURES AND WHAT PRECIP TYPES EACH SYSTEM
WILL HAVE. TEMPERATURES WAVER AROUND FREEZING DEPENDING ON THE
STORM TRACKS. COOLING TUESDAY AND WEDNESDAY SO PROBABLY BY THEN
ALL SNOW AND BELOW NORMAL TEMPERATURES.
PREVIOUS DISCUSSION...
THE OVERALL 500 MB PATTERN DOES NOT CHANGE MUCH THROUGH THIS
PERIOD WITH A BROAD TROF RESIDENT OVER CENTRAL NORTH AMERICA WITH
RELATIVELY MILD SWLY FLOW ACROSS THE CNY/NEPA REGION. THIS WILL
KEEP US IN A RATHER ACTIVE PATTERN WITH TRANSIENT WEATHER SYSTEMS
MOVING THROUGH THE REGION.
MEDIUM RANGE MODEL CONSENSUS IS RATHER POOR...BUT IT DOES APPEAR
THE BEST CHANCE FOR PRECIPITATION WILL BE SAT NIGHT-SUN ASSOCIATED
WITH A COLD FRONT...AND THEN A MORE MARGINAL EVENT SLATED FOR
MONDAY AS LOW PRESSURE LIFTS THROUGH THE TN/OH VALLEY PER THE
ECMWF. THIS IS UNLESS THE GFS/GGEM CONTINUE TO TREND A FLATTER
WAVE OUT TO SEA TO OUR SOUTH MISSING US COMPLETELY. WPC GRIDS SEEM
TO BE HEAVY HANDED ON THE ECMWF SOLUTIONS...BUT GIVEN UNCERTAINTY
INTRODUCED BY GFS/GGEM...WE HAVE SOFTENED THEM TO CHANCE POPS IN
THIS AREA FROM SUN-MON NGT. BEYOND THEN...WEAK WAVES AND PASSING
FLURRIES POSSIBLE THROUGH MID-WEEK.
OVERALL...TEMPERATURES WITHIN THE BROAD SWLY FLOW WILL BE NEAR TO
ABOVE LATE DECEMBER NORMALS.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
1230 AM UPDATE...
MILD MOIST CONDITIONS WILL REMAIN ACROSS THE AREA TONIGHT WITH
MVFR AND IFR CIGS AND MOSTLY MVFR TO VFR VSBYS. AS RAIN MOVES IN
FROM THE SW 8 TO 12Z CIGS SHOULD LOWER TO IFR MOST LOCATIONS AND
VSBYS WILL FALL TO MVFR. CONDITIONS WILL BE FAIRLY PERSISTENT INTO
THIS EVENING. SOME IMPROVEMENT POSSIBLE ELM TOWARD 04Z AND THE
FROPA.
OTHER PROBLEM A STRONG LOW LEVEL JET MOVING IN MIDDAY AND
REMAINING INTO TONIGHT. KEPT THE LLWS GROUP ALL SITES WITH A JET
OUT OF THE SOUTH AT 40 TO 45 KTS.
SFC WINDS E TO SE AT 10 KTS OR LESS. ELM SHIFTING TO S THIS EVE
AND REST CLOSER TO 6Z.
OUTLOOK...
WED NGT...IFR. PERIODS OF RAIN.
THU...BECOMING VFR/MVFR. WINDY WITH RAIN SHOWERS.
FRI/SAT...VFR.
SAT NGT TO SUN...MVFR/IFR. CHC RAIN OR SNOW.
&&
.HYDROLOGY...
WITH THE RAINFALL THE NEXT 3 DAYS RIVERS WILL RISE. IT SHOULD BE
SPREAD OUT ENOUGH THAT RIVER AND FLASH FLOODING IS NOT EXPECTED.
RAINFALL AMOUNTS OF HALF INCH IN THE FAR W AND NW TO 1 TO 1.5
INCHES IN THE FAR SE. RAINFALL MAXES ALONG THE COAST OUTSIDE THE
CWA. HALF AN INCH TO AN INCH ACROSS THE HEADWATERS OF THE NORTH
BRANCH SUSQUEHANNA AND DELAWARE. THIS IS THE AREA TO WATCH WITH
SNOW STILL ON THE GROUND AND EXPECTED TO MELT WITH STRONG WINDS
AND HIGH DEWPOINTS. THIS WOULD ADD AN ANOTHER INCH OF RUNOFF FROM
SNOWMELT. MARFC HAS SEVERAL POINTS GETTING TO CAUTION STAGE BUT
NOT FLOOD. SEEMS REASONABLE. FLASH FLOOD NOT EXPECTED WITH LOW
RAINFALL RATES. HIGHEST RATES UNDER HALF AN INCH AN HOUR THIS AFTN
AND EVE AHEAD OF THE FRONT. ALMOST ALL THE RAIN WILL RUN OFF.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN/DJP
NEAR TERM...DJN/DJP
SHORT TERM...DJN
LONG TERM...JAB/TAC
AVIATION...TAC
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BISMARCK ND
339 AM CST WED DEC 24 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 339 AM CST WED DEC 24 2014
THE MAIN CONCERN IN THE SHORT WILL BE FOG THIS MORNING...THEN
ATTENTION TURNS TO CHANCES OF PRECIPITATION...WITH AND WEATHER TYPE
DURING THE DAY.
CURRENTLY...A WEAK SURFACE RIDGE AXIS EXTENDED ACROSS EASTERN NORTH
DAKOTA - BETWEEN A STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES
AREA AND DEVELOPING LOW PRESSURE IN THE LEE OF THE ROCKIES. ALONG
AND EAST OF THIS RIDGE IS A LARGE STRATUS CLOUD FIELD EXTENDING FROM
THE EASTERN DAKOTAS TO THE GREAT LAKES. IN THE WESTERN DAKOTAS
CIRRUS CLOUDS COVERED MOST OF THE AREA...WITH PATCHY/OCCASIONAL FOG
REPORTED...SOMETIMES LIGHT FOG AND SOMETIMES VISIBILITIES DROP DOWN
TO 1/2 MILE OR LESS FOR SHORT PERIODS.
THE VARIOUS RUNS OF THE HRRR MODEL HAVE SUGGESTED THAT THE WESTERN
EDGE OF THE STRATUS DECK SHOULD ERODE WITH TIME...WITH PATCHY AREAS
OF DENSE FOG FORMING IN THE IMMEDIATE CLEARING OF THE STRATUS.
HOWEVER THE MODEL SUGGESTS THE DENSE FOG NOT LASTING/LINGERING IN
ANY ONE AREA. MEANWHILE INCREASING MID LEVEL CLOUDS MOVING IN FROM
EASTERN MONTANA SHOULD EVENTUALLY LIMIT ANY FOG FORMATION. THUS WILL
KEEP A MENTION OF PATCHY FOG OVER THE WESTERN HALF OF THE STATE
THROUGH AROUND 6 AM...THEN CONTINUE THE PATCHY FOG MENTION OVER ALL
OF CENTRAL NORTH DAKOTA UNTIL AROUND 9 AM.
THE NEXT WEATHER SYSTEM TO AFFECT NORTH DAKOTA IS OVER THE WESTERN
COAST OF NORTH AMERICA EARLY THIS MORNING. BROAD ZONAL FLOW WAS OVER
THE NORTHERN PLAINS AHEAD OF THE SYSTEM WITH LOW PRESSURE IN NORTH
CENTRAL CANADA. THE ZONAL FLOW CONTAINS SOME UPPER LEVEL IMPULSE
ENERGY THAT WAS ASSOCIATED WITH A MID-LEVEL DECK OF CLOUDS OVER
SASKATCHEWAN/MONTANA MOVING EASTWARD...WITH SOME LIGHT RADAR RETURNS
SEEN ON THE RADAR MOSAIC. SURFACE LOW PRESSURE IN THE LEE OF THE
ROCKIES THIS MORNING WILL MOVE EAST ACROSS THE DAKOTAS TODAY. WARM
ADVECTION AHEAD/ALONG THE SYSTEM WAS MOVING INTO WESTERN NORTH
DAKOTA THIS MORNING. THERE IS A SLIGHT CHANCE OF LIGHT PRECIPITATION
WITH THIS UPPER LEVEL ENERGY AS IT MOVES EAST ACROSS THE REGION. THE
MAIN QUESTION IS WHETHER FREEZING RAIN WILL BE AN ISSUE THIS
MORNING. THE APPROACH OF THE MID CLOUD DECK WILL MEAN THAT ICE
CRYSTALS WILL BE LIKELY AT MID AND UPPER LEVELS. SHOULD ANY OF THESE
ICE CRYSTALS FALL INTO LOWER LAYERS OF THE ATMOSPHERE...PROGGED
MODEL SOUNDINGS SUGGEST THAT INITIALLY THERE IS A WARM
LAYER/INVERSION - BUT THAT THE FROST POINT WITHIN THIS LAYER IS MUCH
COOLER THAN THE DRY BULB TEMPERATURE. THUS PARTICLES FALLING THROUGH
SHOULD COOL TOWARDS THE FROST POINT AND REMAIN COOL ENOUGH FOR ALL
SNOW. LATER IN THE DAY AS SURFACE TEMPERATURES WARM ABOVE FREEZING -
MAINLY IN THE WEST - PRECIPITATION WOULD CHANGE TO RAIN.
TONIGHT THE COLD FRONT PORTION OF THE WEATHER SYSTEM WILL MOVE
SOUTHEAST ACROSS THE STATE. AS THIS OCCURS...THE UPPER LEVEL FLOW
BECOMES MORE SOUTHWESTERLY ACROSS THE DAKOTAS - AND THE LEADING EDGE
OF A SERIES OF UPPER LEVEL ENERGY IMPULSES AND MID LEVEL MOISTURE
ARRIVES. BY THIS TIME ANY PRECIPITATION THAT FALLS SHOULD BE IN THE
FORM OF SNOW...OR AT LEAST CHANGING OVER FROM RAIN TO SNOW. MOST OF
THE SNOW SHOULD OCCUR OVER MONTANA AND NORTHERN WYOMING...WITH
SOUTHWESTERN NORTH DAKOTA AND NORTHWESTERN SOUTH DAKOTA RECEIVING
SOME LIGHT SNOW BY CHRISTMAS MORNING. ESTIMATES ARE THAT BY
CHRISTMAS MORNING SNOW AMOUNTS OF AROUND 1/2 INCH WOULD BE COMMON IN
THE SOUTHWEST...MAINLY FROM BEACH TO DICKINSON TO HETTINGER AND
POINTS SOUTH AND WEST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 339 AM CST WED DEC 24 2014
MAIN FORECAST CHALLENGES INVOLVE LIGHT SNOW ACROSS SOUTHERN NORTH
DAKOTA CHRISTMAS DAY AND MUCH COLDER WEATHER BY FRIDAY AND
CONTINUING INTO NEXT WEEK. LATEST 00Z DETERMINISTIC MODELS AS WELL
AS SREF ARE IN GOOD AGREEMENT WITH KEEPING MEASURABLE PRECIP IN THE
FORM OF SNOW ALONG AND SOUTH OF THE ND/SD BORDER ON CHRISTMAS DAY.
THIS INCLUDES THE 00Z NAM WHICH HAS COME BACK IN LINE WITH OTHER
MODEL GUIDANCE WITH A MORE SOUTHWARD LOCATION OF SNOW. MAY SEE
AROUND AN INCH OF SNOW ACCUMULATION CLOSE TO THE STATE BORDER.
WHILE THE SURFACE LOW RESPONSIBLE FOR THIS SNOW MOVES NORTHEAST FROM
THE CENTRAL PLAINS TO THE GREAT LAKES REGION THURSDAY/FRIDAY...
NORTHERLY WINDS WILL ADVECT ARCTIC AIR ACROSS THE NORTHERN PLAINS.
HIGH TEMPS WILL BE IN THE TEENS AND 20S FRIDAY THROUGH THE WEEKEND
BEFORE A STRONGER ARCTIC FRONT PUSHES ACROSS THE REGION EARLY
SUNDAY. SOME DIFFERENCES IN HEIGHT FIELDS DEVELOP BETWEEN
GFS/ECMWF EARLY NEXT WEEK ALTHOUGH BOTH ARE IN AGREEMENT WITH
EXTENSIVE LONG WAVE TROUGH APPROXIMATELY FROM HUDSON BAY TO
INTERMOUNTAIN WEST. GFS HAS -30C CORE AT 850MB OVER NORTHEAST ND
ON TUESDAY WITH THE ECMWF SLIGHTLY WARMER. REGARDLESS...VERY COLD
CONDITIONS EXPECTED WITH WIND CHILLS REACHING DANGEROUS LEVELS
UNDER NORTHWEST FLOW MONDAY NIGHT AND TUESDAY NIGHT WITH 1050MB
SURFACE HIGH SETTING UP OVER WESTERN MONTANA. MAJORITY OF THE CWA
CURRENTLY LOOKS TO REACH WIND CHILL ADVISORY CRITERIA FOR THESE
TIME PERIODS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1236 AM CST WED DEC 24 2014
WIDESPREAD MVFR/IFR WILL CONTINUE FROM KBIS-KMOT-KJMS THIS MORNING
IN CIGS WITH OCNL FOG. GRADUAL CLEARING FROM WEST TO EAST WILL REACH
KBIS-KMOT LINE AFTER 10Z/4 AM CST. KISN-KDIK EXPECTED TO BE VFR WITH
OCNL MVFR IN FOG UNTIL AROUND 10Z-12Z WHEN MID CLOUDS SHOULD MOVE IN
FROM THE WEST AND BREAK UP PATCHY FOG. NEXT SYSTEM MOVING IN FROM
THE WEST EXPECTED TO BRING LOWER CIGS AT KISN/KDIK AFT 00Z AND MAY
BRING LIGHT SNOW TO KDIK. DID NOT MENTION YET IN TAFS AS CONFIDENCE
THAT EXTENT OF LIGHT SNOW IN MONTANA/WYOMING WILL REACH KDIK.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JV
LONG TERM...JNS
AVIATION...JV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1236 AM CST WED DEC 24 2014
.UPDATE...
ISSUED AT 1236 AM CST WED DEC 24 2014
MAIN CONCERN THIS UPDATE IS HOW PATCHY/WIDESPREAD FOG WILL
MATERIALIZE. WESTERN NORTH DAKOTA IS MAINLY CLEAR EXCEPT WITH SOME
HIGH CIRRUS CLOUDS. THERE HAVE BEEN SOME REPORTS OF PATCHY FOG. A
MID CLOUD DECK IS FORECAST TO ENTER THE WEST LATER THIS MORNING
WHICH SHOULD LIMIT THE EXTENT/DENSENESS OF ANY FOG. HOWEVER CENTRAL
NORTH DAKOTA MAY SEE FOG AS THE WESTERN EDGE OF A LARGE LOW CLOUD
DECK CURRENTLY OVER THE EASTERN DAKOTAS/MINNESOTA ERODES/MOVES EAST.
WILL ADD MENTION OF PATCHY FOG OVER CENTRAL NORTH DAKOTA THIS
MORNING.
THE OTHER CONCERN IS TEMPERATURES. IN CLEARING AREAS TEMPERATURES
HAD DROPPED TO AROUND 10 TO 15 DEGREES...THE RISE BACK INTO THE 20S
AS CLOUDS MOVE OVER THE LOCALE. GOING FOR LOWS OF 10 TO 20 BUT
CONFIDENCE IS LOW DUE TO RANDOM CLEARING/FOG EXPECTED DURING THE
EARLY MORNING HOURS.
UPDATE ISSUED AT 932 PM CST TUE DEC 23 2014
CLEARING SKIES WEST RESULTING SOME PATCHY FOG. ADDED THIS TO THE
FORECAST. INCREASING HIGH CLOUDS LATER TONIGHT SHOULD LIMIT THE
EXTENT OF THE FOG HOWEVER. ALSO LOWERED MIN TEMPS ABOUT 5 - 7 DEGREES
SOUTHWEST.
UPDATE ISSUED AT 634 PM CST TUE DEC 23 2014
ADDED A SLIGHT CHANCE FOR SNOW AND FREEZING DRIZZLE ACROSS
NORTHWEST AND CENTRAL NORTH DAKOTA FOR THE EARLY EVENING HOURS.
RADAR RETURNS SUGGEST LIGHT PRECIP SHOWING UP BETWEEN BISMARCK AND
MINOT AS OF 630 PM CST. BUFKIT SOUNDINGS SHOW A LACK OF ICE
CRYSTALS TO ALLOWING SUPER COOLER WATER TO EXIST. THIS THROUGH 9
PM CST. REMAINDER OF THE FORECAST LOOKS GOOD.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 245 PM CST TUE DEC 23 2014
THE MAIN CONCERN IN THE SHORT WILL BE LINGERING LIGHT SNOW
CHANCES THIS AFTERNOON/EVENING...WITH CHANCES FOR RAIN OR SNOW ON
WEDNESDAY.
AFTERNOON REGIONAL RADAR MOSAIC SHOWS LIGHT SNOW ACROSS PARTS OF
WESTERN AND CENTRAL NORTH DAKOTA. THE SNOW HAS DIMINISHED IN
COVERAGE OVER THE PAST COUPLE HOURS...AND SHORT TERM MODELS
SUPPORT THAT TREND. WILL CARRY ONLY SMALL POPS WITH LITTLE TO NO
ADDITIONAL SNOW ACCUMULATION EXPECTED.
CONSIDERED ADDING PATCHY FOG IN THE WEST IN PROXIMITY TO A SURFACE
RIDGE AXIS. THE LATEST HRRR INDICATES THERE IS A CHANCE OF REDUCED
VISIBILITIES LATE TONIGHT INTO EARLY WEDNESDAY...BUT WAS NOT QUITE
CONFIDENT ENOUGH TO PUT IT IN YET. WILL LET LATER SHIFTS MONITOR
AND ADD IF NECESSARY.
H85 WARM AIR ADVECTION INCREASES WEDNESDAY WITH MODELS DIFFERING
IN REGARDS TO THE AREAL COVERAGE OF PRECIPITATION ASSOCIATED WITH
IT. THE SREF GENERALLY SUPPORTS KEEPING THE PRIMARY PRECIPITATION
CHANCES CONFINED TO NORTHERN PARTS OF THE STATE THROUGH WEDNESDAY
AFTERNOON...WHILE THE DETERMINISTIC NAM/GFS/ECMWF BRING CHANCES
FARTHER SOUTH. HAVE EXPANDED SLIGHT CHANCE POPS SOUTHWARD TO
ACKNOWLEDGE THE DETERMINISTIC SOLUTIONS...WHICH ALSO LINES UP WITH
THE H85 WARM AIR ADVECTION. PRECIPITATION TYPE WILL ALSO BE A
CONCERN WITH H85 TEMPERATURES RISING ABOVE ZERO DEGREES CELSIUS IN
THE SOUTHWEST. THE GOOD NEWS IS SURFACE TEMPERATURES ALSO WARM
ABOVE FREEZING IN THAT AREA...BUT IT WILL BE SOMETHING TO WATCH IN
REGARDS TO PRECIPITATION TYPE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 245 PM CST TUE DEC 23 2014
FOCUS IN THE LONG TERM IS ON THE LARGE SCALE UPPER LEVEL TROUGH
MOVING ACROSS THE CENTRAL CONUS THURSDAY INTO THE WEEKEND AND THE
COOLING TREND COMING THIS WEEKEND.
THE 12 UTC MODEL GUIDANCE IS IN GOOD AGREEMENT ON THE LARGE SCALE
PATTERN...PROGRESSING A DEEP UPPER LEVEL TROUGH FROM THE ROCKIES
EARLY THURSDAY TO THE GREAT LAKES REGION SATURDAY. FOR THE NORTHERN
PLAINS THE 12 UTC MODEL GUIDANCE SHOWS THE MAJORITY OF PRECIPITATION
FALLING ACROSS SOUTHEASTERN MONTANA AS WELL AS NORTHERN AND WESTERN
SOUTH DAKOTA WEDNESDAY NIGHT THROUGH FRIDAY...WITH ONLY MINOR
ACCUMULATIONS ACROSS SOUTHERN NORTH DAKOTA. HOWEVER THE 12 UTC RUNS
OF THE NAM AND GEM-NHEM SHOW PRECIPITATION FALLING FURTHER NORTH
ALONG AND SOUTH OF THE I-94 CORRIDOR IN WESTERN AND CENTRAL NORTH
DAKOTA WEDNESDAY NIGHT THROUGH THURSDAY MORNING. WITH THAT SAID
THESE LATEST 12 UTC RUNS ARE OUTLIERS WITH PREVIOUS MODEL RUNS AND
THE CURRENT 12 UTC RUNS OF THE GFS AND ECMWF. WILL HAVE TO WATCH TO
SEE IF THE HEAVIER PRECIPITATION SOLUTIONS OF THE NAM AND GEM-NHEM
CONTINUE OVER THE NEXT FEW MODELS RUNS...AS THEY SUGGEST BETWEEN 2
AND 4 INCHES COULD FALL OVER THE PERIOD WHICH MAY PROMPT HEADLINES.
HOWEVER...AT THIS TIME WENT WITH A MODEL BLEND FOR THE FORECAST AND
THINKING ONLY AROUND AN INCH TO TWO OF SNOW IN THE SOUTHWEST WITH
GENERALLY LESS THAN AN INCH ELSEWHERE...WHICH DOES NOT REQUIRE ANY
HEADLINES.
PRECIPITATION TYPE WEDNESDAY NIGHT THROUGH FRIDAY APPEARS TO BE ALL
SNOW. MID LEVELS SHOULD BE MOIST ENOUGH FOR ICE CRYSTALS AND
TEMPERATURE PROFILES WILL BE BELOW FREEZING SO THAT NO MELTING
OCCURS. SOME FREEZING DRIZZLE IS POSSIBLE AT TIMES THURSDAY NIGHT AS
THE SYSTEM MOVES SOUTHEAST AND MID LEVELS DRY OUT...HOWEVER
ACCUMULATION WOULD BE MINOR AND ANY PERIOD OF FREEZING DRIZZLE WOULD
BE BRIEF. THUS ONLY MENTION OF SNOW IN THE GRIDS FOR NOW.
ARCTIC AIR WILL FILTER IN BEHIND THIS SYSTEM WITH HIGHS DROPPING
FROM THE 20S CHRISTMAS DAY TO THE SINGLE DIGITS NORTH ON FRIDAY AND
TEENS ELSEWHERE. WIND CHILLS SUNDAY NIGHT AND MONDAY NIGHT WILL BE
VERY COLD. CURRENT FORECAST HAS WIND CHILLS APPROACHING 25 BELOW
ZERO ACROSS THE NORTHERN HALF OF THE STATE EARLY MONDAY MORNING AND
DROPPING TO 25 BELOW ZERO TO 35 BELOW ZERO ACROSS MUCH OF THE STATE
MONDAY NIGHT INTO TUESDAY MORNING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1236 AM CST WED DEC 24 2014
WIDESPREAD MVFR/IFR WILL CONTINUE FROM KBIS-KMOT-KJMS THIS MORNING
IN CIGS WITH OCNL FOG. GRADUAL CLEARING FROM WEST TO EAST WILL REACH
KBIS-KMOT LINE AFTER 10Z/4 AM CST. KISN-KDIK EXPECTED TO BE VFR WITH
OCNL MVFR IN FOG UNTIL AROUND 10Z-12Z WHEN MID CLOUDS SHOULD MOVE IN
FROM THE WEST AND BREAK UP PATCHY FOG. NEXT SYSTEM MOVING IN FROM
THE WEST EXPECTED TO BRING LOWER CIGS AT KISN/KDIK AFT 00Z AND MAY
BRING LIGHT SNOW TO KDIK. DID NOT MENTION YET IN TAFS AS CONFIDENCE
THAT EXTENT OF LIGHT SNOW IN MONTANA/WYOMING WILL REACH KDIK.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...CK
LONG TERM...MM
AVIATION...JV
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
418 AM EST WED DEC 24 2014
.SYNOPSIS...
LOW PRESSURE WILL MOVE NORTH OUT OF THE TENNESSEE VALLEY TODAY TO
OHIO AND LAKE ERIE BY THIS EVENING. A TRAILING COLD FRONT WILL SWEEP
EAST ACROSS THE REGION THIS EVENING. STRONG GUSTY WINDS ARE EXPECTED
WITH THIS STORM SYSTEM ACROSS THE AREA. A RIDGE OF HIGH PRESSURE
WILL BUILD NORTH INTO THE REGION BY THURSDAY EVENING. LOW PRESSURE
WILL BUILD NORTHEAST INTO THE NORTHERN LAKES BY SATURDAY FOLLOWED BY
ANOTHER COLD FRONT SATURDAY NIGHT INTO SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE STORM SYSTEM THAT HAS BEEN ADVERTISED FOR THE LAST WEEK HAS
FINALLY ARRIVED. THE STORM SYSTEM IS PROGGED TO MOVE NORTH OUT OF
THE TENNESSEE VALLEY AREA INTO WESTERN OHIO AND WESTERN LAKE ERIE BY
THIS EVENING. THE MAIN PROBLEM WITH THE SYSTEM WILL BE THE STRONG
DAMAGING WINDS ASSOCIATED WITH THE SYSTEM. STRONG LOW LEVEL JET AND
PRESSURE RISE/FALL COUPLET ALONG THE COLD FRONT WILL ALLOW SOME OF
THE STRONGER WINDS ALOFT TO REACH THE SURFACE. THE WINDOW FOR THE
STRONG WINDS APPEARS THAT IT WILL BE A FAIRLY NARROW TIME FRAME FROM
LATE THIS AFTERNOON THROUGH THURSDAY MORNING. WINDS OF 20 TO 35 MPH
WITH GUSTS AS HIGH AS 60 MPH ARE EXPECTED IN THE WESTERN PORTIONS OF
THE FORECAST AREA AND ALONG THE NORTHEAST LAKE SHORE. SLIGHTLY LOWER
WINDS AND WIND GUSTS ARE EXPECTED ELSEWHERE. THEREFORE...A HIGH
WIND WARNING HAS BEEN ISSUED FOR THE WEST HALF AND IMMEDIATE LAKE
SHORE IN THE NORTHEAST. A WIND ADVISORY HAS BEEN ISSUED FOR THE
REST OF THE EASTERN AREAS.
NEXT PROBLEM IS HOW MUCH RAIN ARE WE GOING TO DEAL WITH. SOME
INDICATIONS ARE THAT THE SHOWERS MAY HOLD OFF UNTIL THIS EVENING
OVER MUCH OF THE AREA. HOWEVER...LATEST RADAR AND HRRR MODEL SUGGEST
SOME SCATTERED SHOWER ACTIVITY THROUGH THE DAY. STORM SYSTEM AND
COLD FRONT SHOULD BRING ANOTHER SWATH OF MOISTURE INTO THE REGION
THIS MORNING AND AGAIN THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
OVERALL UPPER LEVEL PATTERN IS PROGRESSIVE AND FAST MOVING. UPPER
LEVEL TROUGH THAT GENERATED THE CURRENT STORM SYSTEM WILL QUICKLY
CAUSE SURFACE LOW PRESSURE SYSTEM TO QUICKLY VACATE THE AREA ON
THURSDAY. ACTUALLY...SOME WARM AIR ADVECTION IS EXPECTED TO DEVELOP
LATER IN THE DAY ON THURSDAY. THIS SHOULD HELP TO BOOST THE
TEMPERATURES POSSIBLY BACK TO THE LOWER 40S.
SYNOPTIC PRECIPITATION FOR THE MOST PART IS EXPECTED TO PULL OUT TO
THE NORTHEAST FAIRLY QUICKLY WITH THE STORM SYSTEM ON THURSDAY. SOME
LINGERING LAKE EFFECT RAIN/SNOW SHOWERS IS POSSIBLE THURSDAY BEFORE
ENDING.
NEXT STORM SYSTEM APPROACHES THE AREA AND IT WILL MAKE ITS PRESENCE
KNOWN FAIRLY QUICKLY AS EARLY AS SATURDAY. A STORM SYSTEM WILL MOVE
EAST INTO THE WESTERN GREAT LAKES AND DRAG A COLD FRONT ACROSS THE
REGION BY SATURDAY NIGHT. MILD TEMPERATURES SHOULD KEEP
PRECIPITATION IN THE FORM OF RAIN THROUGH THE PERIOD. NOT EXPECTING
ANY MAJOR COOL DOWNS THROUGH MUCH OF THE UPCOMING LAST WEEK OF THE
NEW YEAR. HOWEVER...MODELS ARE HINTING AT A FAIRLY MAJOR COLD AIR
OUT BREAK JUST IN TIME FOR THE NEW YEAR TO ARRIVE. SO FAR THIS LOOKS
TO BE COLDEST AIR OF THE SEASON. DEPENDING ON WHICH MODEL YOU LOOK
AT...THE COLD AIR TAKES A GLANCING BLOW WHILE THE OTHER MODEL SLOWS
THE COLD AIR EXITING OUR AREA.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THE EXTENDED IS NOT CLEAR CUT. ON SUNDAY THE THREAT OF SNOW SHOWERS
WILL BE ENDING FROM THE NORTH AS HIGH PRESSURE BUILDS IN. THE ECMWF
IS SLOWER WITH THE PRECIPITATION DECREASE AND WARMER TO START. AT
THIS TIME KEPT THE THREAT JUST SNOW SHOWERS BUT THIS WILL HAVE TO BE
WATCHED. LATE MONDAY INTO TUESDAY THE MODELS BRING A LOW UP INTO THE
OHIO VALLEY. THE POPS MAY HAVE TO BE RAISED IF THE MODELS KEEP
SHOWING THIS TREND. WENT CLOSE TO WPC GUIDANCE FOR THE TEMPERATURE
FORECAST.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
THE LOWEST IFR CEILINGS AND VISIBILITIES WILL LIKELY OCCUR ACROSS
NORTHWEST OHIO THIS MORNING WITH AREAS IF IFR CEILINGS AND VSBY
ACROSS NE OH AND NW PA AS THE WARM FRONT SLOWLY LIFTS NORTH. WE
SHOULD BREAK INTO THE WARM SECTOR ON WEDNESDAY WITH AN INCREASING
SOUTH WIND AND CEILINGS AND VISIBILITIES SLOWLY IMPROVING. A STRONG
COLD FRONT WILL CROSS THE AREA FROM WEST TO EAST LATE WED
AFTERNOON/EVENING WITH SOUTH SOUTHWEST WIND GUSTS 35 TO 40 KNOTS
(OR MORE) INTO WEDNESDAY NIGHT.
.OUTLOOK...NON-VFR LIKELY INTO THURSDAY. NON-VFR DEVELOPING AGAIN
SATURDAY CONTINUING SUNDAY.
&&
.MARINE...
WINDS WILL BE ON THE INCREASE ON THE LAKE ESPECIALLY THIS AFTERNOON
AFTER THE LOW MOVES NORTH AND THE COLD FRONT MOVES THROUGH. SOME
QUESTION ON THE EXACT TIMING OF WHEN THE GALE FORCE WINDS WILL
START. WILL HAVE THE GALE WARNING START ON THE WEST END AT 22Z AND
ON THE EAST END AT 02Z. WE ALSO COULD HAVE A SQUALL LINE MOVE
THROUGH LATE THIS AFTERNOON AND EVENING WITH HIGH WINDS. THE LOW
MOVES QUICK SO THIS WILL BE A QUICK SHOT OF GALE FORCE WINDS. SOME
CONCERN WITH THE 925 MB WINDS ON THE LAKE OVER 50 KNOTS...THE COLD
ADVECTION IS SOMEWHAT GRADUAL SO GOING WITH SUSTAINED OF 40 TO 45
KNOTS WITH HIGHER GUSTS. BECAUSE OF THE GALE FORCE WINDS THE WATER
LEVEL WILL DROP ON THE WEST END OF THE LAKE LATE THIS EVENING...A
LOW WATER ADVISORY WILL BE ISSUED. ONCE THE GALE DECREASE LATE
THURSDAY A SMALL CRAFT ADVISORY WILL BE NEEDED ON THE EAST END.
A MODERATE SOUTHWEST FLOW WILL CONTINUE ON THE LAKE FOR FRIDAY AND
SATURDAY. IT IS IN WARM ADVECTION SO WE MAY NOT NEED A SMALL CRAFT
ADVISORY ON THE LAKE. A COLD FRONT MOVES THROUGH LATE SATURDAY AND
WE MAY NEED A SMALL CRAFT ADVISORY ON THE EAST END OF THE LAKE IN
THE COLD ADVECTION. IT WILL BE SHORT LIVED AS HIGH PRESSURE BUILDS
IN QUICKLY ON SUNDAY. FOR EARLY NEXT WEEK THE FLOW ON THE LAKE WILL
BE EAST AND LIGHT AND LOW PRESSURE MOVES THROUGH THE OHIO VALLEY AND
HIGH PRESSURE IS OVER CANADA.
&&
.CLIMATE...
TEMPERATURES TODAY WILL ATTEMPT TO SURGE INTO THE 60S AND MAY
APPROACH RECORD LEVELS. THE CURRENT RECORDS ARE:
CLEVELAND 65 1964 AKRON-CANTON 63 1964
ERIE 66 1964 MANSFIELD 62 1964
TOLEDO 65 1889 YOUNGSTOWN 63 1982
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...HIGH WIND WARNING FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY
FOR OHZ012-089.
WIND ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY FOR
OHZ013-014-021>023-031>033-038.
HIGH WIND WARNING FROM 3 PM THIS AFTERNOON TO 4 AM EST
THURSDAY FOR OHZ003-006>011-017>020-027>030-036-037-047.
PA...HIGH WIND WARNING FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY
FOR PAZ001.
WIND ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY FOR
PAZ002-003.
MARINE...GALE WARNING FROM 9 PM THIS EVENING TO 4 PM EST THURSDAY FOR
LEZ061-145>149-165>169.
LOW WATER ADVISORY FROM 9 PM THIS EVENING TO NOON EST THURSDAY
FOR LEZ142>144-162>164.
GALE WARNING FROM 5 PM THIS AFTERNOON TO 10 AM EST THURSDAY
FOR LEZ142>144-162>164.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...KIELTYKA
AVIATION...KOSARIK
MARINE...KIELTYKA
CLIMATE...MULLEN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1153 PM EST TUE DEC 23 2014
.SYNOPSIS...
AN INTENSIFYING STORM SYSTEM WILL MOVE NORTHWARD FROM THE WESTERN
GULF COAST TO THE CENTRAL GREAT LAKES BY WEDNESDAY EVENING. THE
ASSOCIATED COLD FRONT WILL PUSH THROUGH CENTRAL PENNSYLVANIA
WEDNESDAY NIGHT. ANOTHER LESS POTENT COLD FRONT WILL MOVE ACROSS
THE AREA THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
DEEP SOUTHERLY FLOW IN ADVANCE OF TROUGH OVR THE PLAINS HAS DRAWN
A PLUME OF GULF OF MEX MOISTURE OVER THE EASTERN CONUS.
SATL-DERIVED PWAT IMAGERY AS OF THIS EVENING IS SHOWING ANOMALOUS
DEEP LYR MOISTURE VALUES ACROSS THE ENTIRE E COAST. FOR THIS
EVENING...WEAK FORCING IN THE FORM OF OROGRAPHIC LIFT WILL PRODUCE
NO MORE THAN DRIZZLE OVR MOST OF CENTRAL PA. HOWEVER...REGIONAL
RADAR LOOP AT 03Z SHOWS A LARGE AREA OF RAIN LIFTING NORTH TOWARD
PA IN ASSOC WITH LL JET AHEAD OF DEVELOPING SFC LOW ON THE GULF
COAST. AS LL JET FEATURE LIFTS NORTH...EXPECT A STEADY RAIN TO
OVERSPREAD THE REGION FROM THE SOUTH OVERNIGHT.
RADAR TRENDS AND LATEST HRRR OUTPUT SUGGEST THE STEADY RAIN WILL
REACH THE S TIER COUNTIES ARND MIDNIGHT AND THE N TIER BY ARND 09Z.
A CALM WIND HAS PROMOTED WIDESPREAD FOG THIS EVENING. HOWEVER...AS
A SERLY BREEZE DEVELOPS LATE TONIGHT...EXPECT THE FOCUS OF THE FOG
TO BE ON THE RIDGES...WITH IMPROVING VSBYS ACROSS THE SUSQ VALLEY.
TEMPS EXPECTED TO REMAIN NEARLY STEADY OVERNIGHT...AVERAGING IN
THE L40S MOST PLACES.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
A RIBBON OF HIGHER DEEP LAYER MOISTURE WILL LIKELY BRING SOAKING
RAINFALL TO CENTRAL PA EARLY IN THE DAY. BY AFTN...MDL DATA
INDICATES THE RAIN SHOULD TAPER OFF AS DRY SLOT WORKS IN FROM
THE SW. LATEST GUIDANCE CONTINUES TO TARGET THE LOWER SUSQ VALLEY
FOR THE HEAVIEST RAIN...WITH 1+ INCH AMTS LIKELY BASED ON 21Z SREF
AND BLEND OF EARLIER OPER RUNS. MUCH LIGHTER AMTS EXPECTED ACROSS
THE NW MTNS.
HI RES MODELS INDICATING A SQUALL LINE TO ACCOMPANY SFC COLD
FRONT LAGGING THE UPPER FRONTAL PASSAGE WEDNESDAY EVENING. EXTENT
OF SURFACE DESTABILIZATION WILL ULTIMATELY DETERMINE HOW STRONG
THIS SQUALL LINE CAN GET...AND HOW STRONG WIND GUSTS CAN BE AT THE
SURFACE...BUT SUFFICE TO SAY ONE OF THE BETTER SEVERE WEATHER
SETUPS FOR CHRISTMAS EVE IS IN STORE FROM EARLY WED EVENING
THROUGH JUST PAST MIDNIGHT ACROSS CENTRAL PA. AS PREVIOUSLY
MENTIONED...EVEN MINIMAL CAPE COMBINED WITH STRONG /DEEP-LAYER
WIND FIELDS A FEW TO SVRL KFT AGL OFTEN RESULTS IN A NCFRB WITH
LOCALIZED DOWNBURST DAMAGE OCCURRING BENEATH MINI BOWS IN THE
LINE. SPC HAS PLACED MUCH OF CENTRAL PA IN MARGINAL CATEGORY FOR
DAY 2 AS A RESULT. MORE DETAILS BELOW.
TEMPERATURES WILL CLIMB INTO THE 50S WED AFTERNOON INTO WED
NIGHT...AS STRONGER SOUTHERLY WINDS DEVELOP. HAVE LOWERED DAYTIME
TEMPS OVR MUCH OF THE AREA...BASED ON LATEST GUIDANCE WHICH
INDICATES PERSISTENT COLD AIR DAMMING. THE WARMEST READINGS OVR
MUCH OF THE AREA MAY NOT BE REACHED UNTIL AFTER DARK WED EVENING.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
ANOMALOUSLY STRONG SSWRLY UPPER JET OF 140-150 KTS WILL ACCOMPANY
THE CFROPA IN THE 04-10Z TIME PERIOD CHRISTMAS DAY. IN
ADDITION...THE UNSEASONABLY WARM AND MOIST AIR WILL HELP TO
PRODUCE A RIBBON OF CAPE UP TO A FEW HUNDRED J/KG.
FOR NOW...HAVE CHC OF THUNDER IN FOR WED EVENING. NORMALLY I WOULD
BE MORE CONCERN ABOUT STRONG TO SEVERE STORMS...BUT BEST FORCING
ACROSS THE OH VLY. ALSO TIME OF DAY NOT THE BEST. HOWEVER...HINTS
OF COLD AIR DAMMING STILL ACROSS CENTRAL ZONES. EITHER
WAY...NORMALLY LIKE TO SEE DEWPTS IN THE UPPER 50S.
STILL EXPECT SOME GUSTY WINDS LATE WED NIGHT INTO THU AM...MOST
LIKELY WILL NEED A WIND ADVISORY...BUT STILL THIRD PERIOD.
TOOK SNOW OUT OF FCST FOR CHRISTMAS...TEMPS NOT COLD ENOUGH.
FRIDAY LOOKS NICE...WITH SW FLOW.
DID UP TEMPS FRIDAY INTO SAT...GIVEN RISING HEIGHTS.
CUT BACK PCPN FOR LATE FRIDAY.
12Z EC RUN HAS SYSTEM FURTHER NW NOW...BUT FOR NOW WENT WITH
SLIGHT CHC OF SNOW FROM SUNDAY INTO EARLY MONDAY MORNING.
AGAIN WITH SPLIT FLOW...THERE COULD BE SOME CHANCE FOR A SOUTHERN
WAVE TO BRING SOME RAIN OR SNOW SHOWERS TO THE AREA AT TIMES...BUT
IT LOOKS LIKE ANYTHING WOULD BE FAST MOVING. PERHAPS A CHANGE
LATER NEXT WEEK...AS CROSS POLAR FLOW SETS UP.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
WIDESPREAD REDUCTIONS IN FOG AND LOW CIGS WILL CONTINUE OVERNIGHT
WITH ENTIRE CWA REMAINING AT IFR/LIFR AS LOW LEVEL MOISTURE FEEDS
IN FROM THE SE FROM A WEAK SFC LOW EAST IF NEW JERSEY COAST...THEN
MAINTAINED AHEAD OF SRLY FLOW OF AN APPROACHING FRONTAL SYSTEM.
INCLUDED LLWS FOR ALL TAF SITES STARTING NEAR SUNRISE WED MORNING
AS WINDS ALOFT BEING TO INCREASE AHEAD OFF APPROACHING FRONTAL
SYSTEM OVER THE MIDWEST WHILE SFC WINDS REMAIN SERLY.
OUTLOOK...
WED...PERIODS OF RAIN ALONG WITH WIDESPREAD REDUCTIONS. SLGT CHC
TSTM NW. BREEZY. LLWS LIKELY.
THU...WINDY AND COLDER WITH SCT MVFR CIGS AND -SHSN. LLWS.
FRI...FAIR AND MOSTLY VFR.
SAT...FAIR AND MOSTLY VFR. SCT SHSN WITH LOCAL REDUCTIONS NW.
SUN...MVFR TO IFR WITH CHC RA/SN...ESP SOUTH.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR/MARTIN
NEAR TERM...FITZGERALD
SHORT TERM...DEVOIR/FITZGERALD
LONG TERM...MARTIN
AVIATION...GARTNER
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
342 AM CST WED DEC 24 2014
.SHORT TERM...
THE 00Z NAM/GFS AND ECMWF HAVE TRENDED EAST WITH LOW EXPECTED TO
TRACK ALONG IN/OH BORDER AND INTO SOUTHEAST MICHIGAN. RAPID
DEEPENING PHASE OF ABOUT 1 MB/HOUR EXPECTED TO START IN THE
MORNING IN OHIO VALLEY AND CONTINUES INTO THE EVENING AS STORM
CROSSES SOUTHEAST MICHIGAN AND BOUND FOR GEORGIAN BAY.
WILL CONTINUE THE PREVIOUS IDEA OF LOWERING THE ACCUMULATING SNOW
AND HAVE CANCELLED THE WINTER WEATHER ADVISORIES. NAM FORECAST
SOUNDINGS SHOW A FAIRLY DRY LAYER FROM 4 TO 13 THSD FT EARLY THIS
MORNING OVER THE FAR SOUTHEAST. THIS DIMINISHES...BUT DEEP
SATURATION IS RATHER BRIEF LATE THIS MORNING AND EARLY AFTERNOON
BEFORE DRYING OCCURS AROUND 10 THSD FT EARLY THIS EVENING. SNOW
RATIOS ARE RATHER LOW IN THE FAR EAST WHERE THE PRECIPITATION WOULD
BE MORE. THE 12Z ECMWF HAS LITTLE IF ANY MEASURABLE PRECIPITATION
OVER SOUTHEAST WISCONSIN. THE HRRR IS THE MOST AGGRESSIVE MESO MODEL
WITH AROUND 0.15 OF PRECIPITATION OVER THE LAKESHORE COUNTIES.
HOWEVER EVEN THIS WOULD BE LIMITED DUE TO THE CONSENSUS 6 TO 1 SNOW
RATIOS.
THE NEW 06Z NAM CONTIUES THE EASTWARD TREND AND NOW AGREES WITH THE
ECMWF WITH LITTLE IN THE WAY OF MEASURABLE PRECIPITATION OVER
EASTERN WISCONSIN.
CHRISTMAS DAY...FORECAST CONFIDENCE HIGH.
HIGH PRESSURE CENTERED OVER THE GULF COASTAL STATES WILL STRETCH ITS
AXIS UP INTO THE GREAT LAKES FOR CHRISTMAS...BRINGING A DRY AND
RATHER PLEASANT DAY WITH HIGHS IN THE MID TO UPPER 30S. WE MIGHT
EVEN SEE A LITTLE SUNSHINE.
.LONG TERM...
FRIDAY THROUGH SATURDAY... FORECAST CONFIDENCE MEDIUM.
FRIDAY WEATHER WILL REMAIN QUIET AND MILD OVER SOUTHERN WI. HIGHS
ARE EXPECTED IN THE LOWER 40S WITH A SOUTHERLY BREEZE. THERE WILL
LIKELY BE LOW CLOUDS AROUND DUE TO THE LOW LEVEL MOISTURE SPREADING
BACK INTO THE REGION.
A WEAK SURFACE LOW PRESSURE TROUGH AND COLD FRONT WILL SLIDE THROUGH
SOUTHERN WI FRIDAY NIGHT. MEANWHILE... A 500MB SHORTWAVE WITHIN THE
LEFT EXIT REGION OF A STRENGTHENING UPPER JET WILL BE TRACKING
THROUGH CENTRAL AND NORTHERN WI. MODELS ARE SHOWING TWO AREAS OF
PRECIP ASSOCIATED WITH THIS SYSTEM... ONE MAINLY IN IL THAT CLIPS
SOUTHEAST WI AND THE OTHER OVER THE NORTHWEST HALF OF WI. THE MKX
FORECAST AREA WILL LAND BETWEEN THESE TWO FAVORED AREAS. THE GFS AND
NOW THE 06Z NAM SHOW THESE TWO AREAS CLEARLY IN THE QPF FIELD AND
THE ECMWF DOES TO A LESSER EXTENT.
TEMPERATURE PROFILES SHOW THAT MOST OF THE PRECIP IN SOUTHEAST WI
WILL FALL AS RAIN AND THEN GRADUALLY CHANGE OVER TO SNOW OVERNIGHT
INTO SATURDAY MORNING BEFORE ENDING. IN THE NORTHERN FORECAST
AREA... THE TEMP PROFILE IS COLDER AND WE ARE LOOKING AT A RAIN/SNOW
MIX CHANGING OVER TO SNOW BY MIDNIGHT. PRECIP AMOUNTS WILL BE
LIGHT... LESS THAN A TENTH OF AN INCH. ANY SNOW ACCUMULATION WOULD
BE LESS THAN A HALF INCH.
THE ECWMF HANGS ONTO THE LIGHT PRECIP LONGER IN SOUTHEAST WI THAN
THE GFS ON SATURDAY. COLD AIR ADVECTION AND CLOUDS WILL LEAD TO
STEADY TEMPS AROUND 30 THROUGH THE DAY.
SUNDAY THROUGH TUESDAY... FORECAST CONFIDENCE HIGH.
SURFACE HIGH PRESSURE AND DRY WEATHER WILL DOMINATE FOR SUNDAY AND
MONDAY... BUT TEMPERATURES WILL BE BELOW AVERAGE.
ANOTHER BROAD TROUGH WILL CROSS THE COUNTRY EARLY NEXT WEEK AND MAY
BRING SOME LIGHT SNOW ACROSS WISCONSIN ON A SHORTWAVE MONDAY NIGHT
INTO TUESDAY.
THEN A DEEPER UPPER LEVEL TROUGH IS FORECAST TO DROP DOWN FROM
CANADA THROUGH THE UPPER MIDWEST AND BRING JANUARY-LIKE TEMPERATURES
INTO THE REGION FOR THE NEW YEAR.
&&
.AVIATION/12Z TAFS/...
EXPECT IFR/LIFR CIGS OVER MUCH OF SOUTH CENTRAL AND PORTIONS OF
SOUTHEAST WISCONSIN. LIFR FOG EXPECTED TO PERSIST FOR A FEW HOURS
AFTER SUNRISE OVER PORTIONS OF SOUTH CENTRAL WISCONSIN.
OVER THE FAR SOUTHEAST IFR CIGS POSSIBLE LATER THIS MORNING AND
AFTERNOON. DUE TO THE EXPECTED MIX OF RAIN AND SNOW FAR EAST
TEMPERATURES IN THE MID TO UPPER 30S AT SURFACE MAY PREVENT
SIGNIFICANT CHANGEOVER AND PAVEMENT MAY REMAIN MAINLY WET THROUGH
THE PRECIPITATION DURATION. HOWEVER STILL SOME ACCUMULATIONS ARE
POSSIBLE.
&&
.MARINE...
RAPID DEEPENING LOW WILL RESULT IN BRISK NORTH AND THEN NORTHWEST
WINDS THIS AFTERNOON INTO EARLY THURSDAY. WITH THE LOW GOING FURTHER
EAST THE THREAT OF GALES IS DIMINISHING ON THE WEST SIDE OF LAKE
MICHIGAN SO CURRENT SMALL CRAFT ADVISORY SHOULD SUFFICE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM NOON TODAY TO NOON CST THURSDAY FOR
LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
THURSDAY THROUGH TUESDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
326 AM CST WED DEC 24 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CST WED DEC 24 2014
THE MAIN FOCUS FOR TODAY IS WITH THE CHANCES FOR SNOW/DRIZZLE.
CURRENTLY...A SHEARED OUT/POSITIVELY TILTED MID LEVEL CLOSED
TROUGH EXTENDS FROM THE UPPER MISSISSIPPI RIVER VALLEY ON DOWN TO
THE WESTERN GULF WITH THE SHEAR AXIS RIGHT OVER WEST CENTRAL
WISCONSIN/EASTERN IOWA. AT THE SURFACE...A LOW/TROUGH IS CENTERED
OVER SOUTHEAST WISCONSIN WITH NORTHWESTERLY FLOW RUNNING ACROSS
THE REGION ON THE BACK SIDE OF THIS SYSTEM. NOT MUCH IN THE WAY OF
COLD AIR BEHIND IT WITH 850MB TEMPERATURES AROUND -5C.
PRECIPITATION-WISE...DRIZZLE HAS DEVELOPED IN A BAND NORTHWEST OF
THE SURFACE LOW AND ALONG THE MID LEVEL SHEAR AXIS ALONG THE
TROUGH. 24.06Z RAP SOUNDINGS FROM ALONG THIS BAND SHOW THAT THERE
IS A LACK OF ICE ALOFT WITH SATURATED LOW LEVELS. THESE SOUNDINGS
SHOW SOME COOLING AROUND 700MB WHICH COULD PUSH THE SATURATED
LAYER DOWN INTO THE -8C RANGE AND PERHAPS CAUSE A CHANGE OVER TO
LIGHT SNOW. WITH FORCING WEAK...EXPECT THAT DRIZZLE WILL BE THE
MAIN PRECIPITATION TYPE WITH IMPACTS MINIMAL THANKS TO SURFACE
TEMPERATURES AT 32 TO 36F. THE 24.06Z HRRR/RAP TAKES THIS MAIN
BAND EASTWARD THROUGH THE MORNING AND DIMINISHING ALONG THE WAY.
AS THE TROUGH/LOW SHIFT OFF TO THE EAST TONIGHT...MID
LEVEL/SURFACE RIDGING WILL PUSH IN FROM THE WEST AND MAY OFFER A
BRIEF PERIOD WHERE SKIES CLEAR OUT LATE TONIGHT. HAVE PLAYED SKY
COVER ON THE PESSIMISTIC SIDE SINCE AS SOON AS THE LOW LEVEL
MOISTURE SHIFTS EAST...SOME HIGH LEVEL CLOUD COVER APPEARS TO MOVE
IN ACCORDING TO THE 24.00Z NAM/GFS. TEMPERATURES WILL NOT DIVE
MUCH TONIGHT WITH LOWS ONLY IN THE MID 20S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 326 AM CST WED DEC 24 2014
THE FOCUS THEN SHIFTS TO PRECIPITATION CHANCES WITH THE NEXT
SYSTEM TO MOVE IN ON THURSDAY INTO FRIDAY NIGHT. RETURN SOUTHERLY
LOW LEVEL FLOW WILL BRING WARMER AIR UP FROM THE SOUTHERN PLAINS.
THERE HAS BEEN A FAIRLY CONSISTENT MESSAGE FROM THE 24.00Z AND
PREVIOUS MODELS RUNS THAT SHOW A 900-800MB FRONTOGENETIC BAND
DEVELOPING THURSDAY AFTERNOON ACROSS CENTRAL MINNESOTA INTO
NORTHERN WISCONSIN. LOCALLY...24.00Z NAM/GFS ARE SHOWING SOME LOW
LEVEL SATURATION WITH THE WARM AIR ADVECTION TAKING PLACE THURSDAY
NIGHT. IF FORCING WAS A BIT STRONGER IN THE LOW LEVELS...THERE
WOULD BE THE POTENTIAL TO GET SOME DRIZZLE TO FORM BUT AT THE
MOMENT IT LOOKS TOO WEAK.
BROAD MID LEVEL TROUGHING WILL MOVE INTO THE REGION FRIDAY/FRIDAY
NIGHT AND BRING THE NEXT BEST CHANCE FOR SOME SNOW AS IT COMES
THROUGH. AS THE DEEPER LIFT COMES IN WITH A MID LEVEL SHORT WAVE
TROUGH TRACKING THROUGH IOWA...SNOW SHOULD DEVELOP IN A SOUTHWEST
TO NORTHEAST BAND. WITH QPF AMOUNTS AROUND A TENTH OF AN INCH OR
LESS...EXPECT THAT ANY ACCUMULATIONS WILL BE MINOR AT AN INCH OR
LESS.
THE PASSING OF THIS TROUGH WILL MARK A PERIOD OF COLDER AIR
ADVANCING INTO THE REGION FROM CANADA. A VERY CONSISTENT SIGNAL IN
THE 24.00Z GFS/ECMWF IS WITH ANOTHER WAVE OF COLDER AIR MOVING
DOWN FROM NORTHERN CANADA FOR THE MIDDLE PART OF NEXT WEEK WITH
850MB TEMPERATURES FORECAST TO DROP TO -20C OR LOWER.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 1100 PM CST TUE DEC 23 2014
EXTENSIVE IFR/MVFR CLOUD SHIELD ACROSS THE REGION...AND DON/T EXPECT
MUCH CHANGE THROUGH WEDNESDAY. NAM RH FIELDS/BUFKIT SOUNDINGS
SUGGEST A BREAK CHRISTMAS NIGHT...BUT IT WOULD BE SHORT LIVED.
WITH THE AMPLE LOW LEVEL MOISTURE HOLDING FAST UNDER THE
INVERSION...COULD HAVE SOME VSBY REDUCTIONS FROM BR AND POTENTIALLY
-DZ. LITTLE EVIDENCE VIA LATEST SFC OBS/RADAR IMAGERY THOUGH. AFTER
12Z...HRRR/NAM12/GFS ALL SUGGEST ENOUGH THERMODYNAMIC/FRONTOGENETIC
LIFT WITH A SFC BOUNDARY TO SPARK AREAS OF LIGHT PCPN FOR WED
MORNING. ITS UNCLEAR IF THERE WILL BE ICE IN THE CLOUD...AS BUFKIT
SOUNDINGS HOVER CLOSE TO -10 C WITH CLOUD TOPS. DEPTH IS GOOD...AND
POTENTIALLY DEEP ENOUGH FOR -RA AS OPPOSED TO -DZ. IF IT WOULD BE
JUST SNOW...A BRIEF DIP TO 2SM WOULD BE POSSIBLE. MOST OF THIS
ACTIVITY SHOULD SHIFT EAST BY 18Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1008 PM CST TUE DEC 23 2014
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATE...
ISSUED AT 840 PM CST TUE DEC 23 2014
JUST SOME LINGERING LGT PCPN ACRS THE FCST AREA EARLY THIS
EVENING. KGRB 88D STILL HAD AN AREA OF RETURNS LIFG NEWD TO THE W
OF THE FOX VALLEY...PROBABLY JUST SOME SPRINKLES. OTHERWISE...SFC
OBS INDICATED MAINLY PATCHY DZ/FZDZ...WITH SOME FLURRIES IN THE N.
MODEL FCST SOUNDINGS SHOW MID-LVL DRY AIR TO REMAIN IN PLACE
THROUGH THE NGT AND INTO TOMORROW MORNING...SUGGESTING JUST
DZ/FZDZ AS PCPN TYPE. BUT CARRIED FLURRIES IN THE FCST FOR N-C
ANYWAY AS STLT HAS A LITTLE COLDER CLD TOPS THERE.
A SMALL PORTION OF THE FCST AREA FM ABOUT MFI/ISW ENEWD TOWARD
WAUSAUKEE HAS PRETTY GOOD CONDITIONS FOR FOG THIS EVENING. THAT
AREA GOT ENOUGH SNOW IN THE PAST 24 HRS TO HAVE SNOW-COVERED
GROUND. WINDS IN THAT AREA ARE LGT AS THAT IS ALONG THE TRACK OF
ELONGATED AREA OF SFC LOW PRESSURE DRIFTING SLOWLY NEWD ACRS THE
AREA. IT/S ALSO AN AREA WHERE SFC DWPTS HAVE CREPT AOA FZG. PLAN
TO CONT TO HANDLE WITH AN SPS...AND WL LIKELY RE-ISSUE THE CURRENT
SPS TO COVER THE SITN INTO THE EARLY MORNING HOURS.
FINALLY...STILL KEENLY WATCHING HOW THE LATEST GUIDANCE IS
HANDLING THE SECONDARY CYCLONE THAT WL LIFT NWD ALONG THE
BAROCLINIC ZONE IN THE NEXT 24-36 HRS. THE NAM HAS SEEMINGLY
SETTLED IN ON A TRACK THAT KEEPS THE PCPN JUST TO OUR E. HAVE ALSO
BEEN WATCHING THE ENDING OF THE HOURLY RAP RUNS...AND THE PAST FEW
OF THOSE GRAZED THE LAKESHORE TOMORROW AFTN/EVENING...AND EVEN
BROUGHT PCPN BACK INTO THE ERN FOX VALLEY AT TIMES.
THE REAL PROBLEM WE/VE HAD DEALING WITH THIS SYSTEM ACTUALLY
ISN/T SO MUCH THE TRACK OF THE CYCLONE. THAT HAS CERTAINLY BEEN
CHAOTIC ON THE NUMERICAL GUIDANCE...BUT WITH A TYPICAL
CYCLONE...THE ENVELOPE OF SOLUTIONS OUT THERE NOW WOULD ALLOW FOR
DECENT CONFIDENCE IN POPS AND A BALLPARK ESTIMATE OF
PCPN/SNOW. THE REAL PROBLEM HAS BEEN THE VERY NARROW/COMPRESSED
DEFORMATION ZONE ON THE WRN FLANK OF THE CYCLONE. THAT SEEMS TO BE
THE RESULT OF HAVING A FAIRLY SMALL CYCLONE...AND THE INTERACTION
OF THE CYCLONE WITH UPSTREAM ENERGY DRIVING EWD ACRS THE NRN
PLAINS. THAT ENERGY WL IMPINGE ON THE DEFORMATION ZONE ON THE WRN
FLANK OF THE CYCLONE...SO THE WIDTH OF THE PCPN W OF THE STORM
CENTER IS UNUSUALLY NARROW. IN ANY CASE...CURRENT FCST SEEMS TO
HAVE THINGS HANDLED FAIRLY WELL...WITH CHC POPS ERN FOX VALLEY AND
SOME LIKELY POPS RIGHT AT THE LAKESHORE. NO SIG CHGS TO THAT THIS
EVENING.
UPDATED GRIDS SENT ABOUT 1/2 HR AGO.
UPDATE
ISSUED AT 526 PM CST TUE DEC 23 2014
UST LGT PCPN LINGERING ACRS N-C WI...SO WL ALLOW THE ADVISORY TO
EXPIRE AT 6 PM AS SCHEDULED.
&&
.SHORT TERM...TONIGHT AND WEDNESDAY
ISSUED AT 237 PM CST TUE DEC 23 2014
MAIN FCST CONCERNS DEAL WITH THE DEMISE OF ONE SYSTEM AND ITS
ASSOCIATED SNOW TNGT AND THEN TRYING TO FIGURE OUT THE PATH OF THE
NEXT SYSTEM TOWARD THE GREAT LAKES ON WED.
THE 20Z MSAS SFC ANALYSIS SHOWED A WEAKENING AREA OF LOW PRES OVER
CNTRL WI MOVING ALONG A QUASI-STNRY BOUNDARY. THIS BOUNDARY WAS
SEPARATING WARM...MOIST AIR ON SOUTH WINDS OVER ERN WI FROM COOL...
MOIST AIR OVER WRN WI ON NORTH WINDS. RADAR MOSAIC CONTINUED TO
SHOW PCPN PIVOTING AROUND THE SFC LOW WITH MAINLY LIGHT RAIN OR
DRIZZLE OVER ERN WI AND EITHER LIGHT SNOW OR A RAIN/SNOW MIX OVER
CNTRL WI. PLAN ON CANCELING THE WINTER WX ADVY FOR ALL BUT VILAS/
ONEIDA COUNTIES WHERE SNOW INTENSITY IS LIGHT OR MIXED PCPN HAS
TAKEN OVER.
SYSTEM OVER THE GREAT LAKES REGION WL CONT TO DRIFT NE AND
STEADILY WEAKEN TNGT AS MAIN ENERGY SHIFTS TOWARD THE TN/OHIO
RIVER VALLEYS WHERE A STRENGTHENING SFC LOW TO RESIDE. FCST
SOUNDINGS INDICATE A LOSS OF MID-LEVEL SATURATION WHICH WOULD
DIMINISH ANY PCPN MAINLY TO EITHER FREEZING DRIZZLE OR DRIZZLE
DEPENDING ON SFC TEMPS. LOW-LEVELS OF THE ATMOSPHERE REMAIN
MOIST...SO PATCHY FOG TO BE A GOOD BET. ANOTHER MILD NGT ON TAP
ACROSS THE FCST AREA WITH MIN TEMPS ONLY RANGING FROM AROUND 30
DEGS N-CNTRL TO THE LWR TO MID 30S NEAR LAKE MI.
EVEN AT THIS LATE DATE...THE MODELS CONT TO STRUGGLE WITH THE
MOVEMENT OF THIS SFC LOW AS IT LIFTS N-NE INTO THE GREAT LAKES ON
WED. AN ERN TRACK (TOWARD DETROIT) PER ECMWF/GEM WOULD ESSENTIALLY
KEEP ANY SNOW POTENTIAL TO OUR EAST AND LEAVE NE WI CLOUDY WITH
ONLY A MINIMAL CHC OF ANY PCPN. A WRN TRACK (TOWARD CNTRL SECTIONS
OF LWR MI) PER NAM/GFS WOULD BRING THE THREAT OF MEASURABLE SNOW
TO ERN WI. THE FINAL SOLUTION MAY NOT BE KNOWN UNTIL THE SFC LOW
ACTUALLY DEVELOPS OVER THE OZARKS AND MAKES IT MOVE TO THE N-NE.
FOR NOW...HAVE SPLIT THE MODEL DIFFERENCE WHICH BRINGS A GLANCING
BLOW TO FAR ERN WI WED AFTERNOON...BUT HAVE KEPT ANY SNOW
ACCUMULATIONS TO LESS THAN AN INCH. ANYONE WITH TRAVEL PLANS
TOWARD SE WI OR NRN IL WL WANT TO CHECK THE LATEST FCSTS AS TRAVEL
MAY BECOME QUITE MESSY DOWN THAT WAY. MAX TEMPS FOR WED WL RANGE
FROM THE LWR 30S OVER N-CNTRL WI TO THE MID 30S ACROSS ERN WI.
.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
ISSUED AT 237 PM CST TUE DEC 23 2014
PROGS CONTINUE TO HINT OF SOME PRECIPITATION BRUSHING OVER FAR
EASTERN WISCONSIN WEDNESDAY EVENING UNTIL THE UPPER LOW SYSTEM
SHIFTS EASTWARD. AFTER A PERIOD OF BLUSTERY NORTHWEST WINDS
WEDNESDAY EVENING...DIMINISHING WINDS EXPECTED OVERNIGHT AS A WEAK
RIDGE OF HIGH PRESSURE WORKS INTO THE AREA.
XMAS DAY EXPECTED TO BE QUIET...THEN LIGHT SNOW WILL BE ON THE
INCREASE LATE IN THE WEEK AS A TROUGH OF LOW PRESSURE AND MID
LEVEL SHORT WAVE SLIDE OVER THE MID SECTION OF THE COUNTRY. PROGS
SUGGEST THE LIGHT SNOW APPEARS TO BE FOCUSED IN THE TRAILING
BAROCLINIC PORTION FROM NORTHWEST WISCONSIN LATE THURSDAY NIGHT
INTO FRIDAY BEFORE TROUGH PASSAGE FRIDAY AFTERNOON INTO EVENING.
FORECAST TEMPS SUGGEST A VERY LIGHT MIX POSSIBLE OVER EAST CENTRAL
WISCONSIN FRIDAY AFTERNOON.
THE QUIET ZONAL FLOW WITH SLIGHTLY COOLER THAN NORMAL TEMPERATURES
WILL CONTINUE INTO THE WEEKEND. MEDIUM RANGE MODELS ARE NOT
INDICATING MUCH SNOW WITH A SHORT WAVE DROPPING INTO THE GREAT
LAKES REGION WHICH DEEPENS THE TROUGH OVER THE REGION EARLY NEXT
WEEK. THERE IS SOME AGREEMENT WITH AN ARCTIC SURGE OF AIR BY THE
MIDDLE OF NEXT WEEK AND USUALLY A CLIPPER TYPE SYSTEM PRECEDES
THIS BUT SO FAR NO INDICATION. AVAILABLE PROGS SUGGESTS SOME
SLIGHT MODERATION IN TEMPS LATE NEXT WEEK.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1006 PM CST TUE DEC 23 2014
PLENTY OF LINGERING LOW-LEVEL MOISTURE WL REMAIN ACRS THE AREA
OVERNIGHT AND INTO WEDNESDAY MORNING. CORRIDOR ACRS CENTRAL INTO
NE WI NR SFC LOW WL HAVE LGT WINDS AND MOISTURE OVER THE RECENT
SNOW...AND MAY HAVE SOME PATCHY DENSE FOG OVERNIGHT. THAT
CORRIDOR SHOULD FALL MAINLY BTWN THE C AND E-C WI TAF SITES...BUT
COULD CREEP BACK INTO CWA/AUW SO WL CARRY SOME LOW VSBYS AT THOSE
SITES. OTHERWISE...MORE SIG IMPROVEMENT IN CONDITIONS WL HAVE TO
WAIT UNTIL TOMORROW WHEN NLY FLOW STRENGTHENS ON THE WRN FLANK OF
CYCLONE LFTG ACRS LOWER MICHIGAN.
&&
.HYDROLOGY...
ISSUED AT 237 PM CST TUE DEC 23 2014
MILD CONDITIONS OVER NORTHEAST WISCONSIN THROUGH WEDNESDAY ALONG
WITH RAINFALL AMOUNTS OF 0.25 TO 0.75 INCHES THROUGH TUESDAY
AFTERNOON MAY AFFECT ICE CONDITIONS ON AREA RIVERS AND LAKES.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE.........SKOWRONSKI
SHORT TERM.....KALLAS
LONG TERM......TDH
AVIATION.......SKOWRONSKI
HYDROLOGY......TDH
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
512 AM PST WED DEC 24 2014
...LOCALLY BLUSTERY CONDITIONS NEAR THE COAST AND IN THE HILLS TONIGHT
THROUGH CHRISTMAS MORNING...
...MUCH COOLER WEATHER BY CHRISTMAS DAY...
.SYNOPSIS...A COLD FRONT WILL SWEEP ACROSS THE REGION TODAY
LEADING TO AREAS OF LIGHT RAIN. BRISK NORTHWEST WINDS WILL DEVELOP
BEHIND THE COLD FRONT BY LATE IN THE AFTERNOON. LOCALLY STRONG
AND GUSTY WINDS WILL OCCUR ALONG THE COAST AND IN THE HILLS
TONIGHT INTO CHRISTMAS MORNING. OTHERWISE CHRISTMAS DAY WILL BE DRY AND
COOL WITH DRY WEATHER EXPECTED TO CONTINUE THROUGH NEXT WEEK.
FREEZING OVERNIGHT LOW TEMPERATURES ARE LIKELY FOR SOME INLAND
VALLEYS LATE IN THE WEEK AND INTO THE WEEKEND.
&&
.DISCUSSION...AS OF 3:00 AM PST WEDNESDAY...SIMILAR TO THE PAST
FEW MORNINGS PATCHY FOG HAS DEVELOPED ACROSS PORTIONS OF OUR
CWA...IN PARTICULAR OVER THE NORTH BAY PLUS AROUND SF BAY. SOME
REPORTS OF VERY LOW VISIBILITIES IN A FEW SPOTS. IN FACT OAKLAND
HAS DROPPED DOWN TO AN EIGHT OF A MILE AND A SPOTTER IN THE
BERKELEY AREA REPORTED VERY LOW VALUES AS WELL. OUTSIDE OF THE FOG
ALSO WORTH NOTING THAT TEMPS ARE RUNNING 2 TO 5 DEGREES COOLER
THAN YESTERDAY IN MOST SPOTS ALONG WITH DEW POINTS RUNNING ABOUT
THE SAME AMOUNT LOWER.
ONCE THE FOG BURNS OFF THE MAIN STORY FOR TODAY WILL BE A COLD
FRONT THAT WILL SWEEP THROUGH OUR AREA AND PROVIDE ANOTHER ROUND
OF RAIN ESPECIALLY FOR THE NORTHERN THIRD OF THE CWA. LATEST
GUIDANCE IN IS IN FAIRLY GOOD AGREEMENT THAT RAIN WILLS START OVER
THE NORTH BAY LATE IN THE MORNING TO EARLY AFTERNOON AND PROGRESS
DOWN TO THE SF BAY REGION OVER THE AFTERNOON AND THEN DISSIPATE BY
THE EVENING AS IT ENTERS THE MONTEREY BAY REGION. RAINFALL AMOUNTS
WILL BE VERY LIGHT COMPARED TO RECENT STORMS HOWEVER LOCALLY MORE
THAN A QUARTER OF AN INCH IS POSSIBLE ESPECIALLY ALONG THE COAST
FROM SAN MATEO COUNTY TO THE NORTH. URBAN LOCATIONS WILL LIKELY BE
CLOSER TO A TENTH OF AN INCH. WORTH NOTING THAT THE NEWEST RUN OF
THE HRRR JUST IN HAS BACKED OFF A BIT WITH THE QPF.
WHAT WILL LIKELY BE A BIGGER STORY OUT OF THE SYSTEM GOING THROUGH
TODAY WILL BE WIND AND COOLER TEMPERATURES. WINDS WILL PICK UP AS
THE FRONT GOES THROUGH AND COLDER AIR MOVES INTO THE AREA. 850 MB
SPEEDS PICK UP TO THE 35 TO 50 KT RANGE WITH MODEL SOUNDINGS
KEEPING THE STRONGER SPEEDS GENERALLY ABOVE THE 1000 FT LEVEL
SUGGESTING THAT THE BIGGEST IMPACTS WILL BE OVER THE HILLS. DUE TO
RECENT RAIN WOULD EXPECT TO GET REPORTS OF TREES BEING TOPPLED
ESPECIALLY FOR ANY SPOTS ALONG RIDGES THAT HAVE A NW EXPOSURE.
LOCAL GUSTS TO 40 MPH CAN BE EXPECTED ABOVE 2000 FEET.
TEMPERATURES WILL DECREASE BOTH DURING THE DAY AND AT NIGHT OVER
THE NEXT COUPLE OF DAYS AND MUCH COOLER AND DRIER AIR SETTLES
ACROSS THE CWA. BIGGEST CONCERN WILL BE THE OVERNIGHT LOWS
ESPECIALLY BY THURSDAY AND FRIDAY NIGHT. BOTH OF THESE WILL LIKELY
HAVE SOME OF OUR COOLEST READINGS IN QUITE SOME TIME WITH INTERIOR
SPOTS FORECAST TO DROP INTO THE 30S WITH EVEN SOME UPPER 20S NOT
OUT OF THE QUESTION. COASTAL SPOTS WILL STAY A BIT MILDER THANKS
IN LARGE PART TO SEA SURFACE TEMPERATURES STILL RUNNING WELL ABOVE
NORMAL.
THE COOLER AND DRY WEATHER WILL CONTINUE INTO NEXT WEEK AS THE
OVERALL FLOW REMAINS FROM THE NW. OUTSIDE OF THE CHANCE OF RAIN
TODAY NO SIGN OF PRECIPITATION OUT THROUGH NEXT FRIDAY.
&&
.AVIATION...AS OF 5:00 AM PST WEDNESDAY...LOW CIGS WITH PATCHY
DENSE FOG IS PRESENT AGAIN THIS MORNING AROUND THE SFO BAY AREA.
OAK VSBY HAS BEEN 1/8 TO 1/4 MILE OVERNIGHT. SO THE POSSIBILITY
EXISTS THAT SFO VSBYS MAY DROP TO 1/4 TO 1/2 MILE BETWEEN 14Z AND
18Z. COMPLICATING THINGS IS THE APPROACHING FRONTAL SYSTEM WHICH
MAY PROVIDE ENOUGH MIXING TO KEEP FOG OUT OF SFO. WINDS WILL BE
LIGHT THIS MORNING BUT WILL BECOME A FACTOR WHEN THE FRONT
ARRIVES IN THE SFO BAY AREA AFTER 22Z. NORTHWEST WINDS EXPECTED TO
INCREASE TO 15-20 KT WITH GUSTS 25-30 KT.
VICINITY OF KSFO...IFR CIGS WITH VSBYS POSSIBLY LOWERING TO 1/4 TO
1/2 BETWEEN 14Z AND 18Z. BY 19Z CIGS WILL LIFT TO MVFR RANGE BUT
APPROACHING FRONT LIKELY TO KEEP THESE CIGS IN THROUGH THE REST OF
THE DAY. A BRIEF PERIOD OF LIGHT RAIN IS EXPECTED 22Z-02Z WITH
RAPID CLEARING AFTER THAT AS THIS IS A QUICK MOVING SYSTEM. WINDS
INCREASING TO NORTHWEST 15-20 KT WITH GUSTS 25-30 KT AFTER 22Z.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...PATCHY IFR CIGS AROUND MRY THROUGH
15-16Z. MVFR CIGS AFTER 23Z WITH OCCASIONAL LIGHT RAIN THROUGH 03Z.
SOUTHEAST WINDS TO 10 KT THIS MORNING WITH STRONGEST WINDS THROUGH
THE SALINAS VALLEY. WINDS SWITCHING TO NORTHWEST 10-15 KT WITH
GUSTS AS HIGH AS 20 KT AFTER 21Z.
&&
.MARINE...AS OF 3:00 AM PST WEDNESDAY...A FAST MOVING TROUGH AND COLD
FRONT WILL MOVE SOUTHEAST OVER THE AREA THIS AFTERNOON AND
EVENING. STRONG NORTHWEST WINDS WILL DEVELOP OVER THE COASTAL
WATERS TONIGHT AND THURSDAY AFTER THE FRONT PASSES WITH GALE FORCE
WINDS OVER THE OUTER WATERS.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...GLW...PT ARENA TO PT REYES 10-60 NM FROM 1 PM
GLW...PT REYES TO PIGEON PT 10-60 NM FROM 1 PM
GLW...PIGEON PT TO PT PINOS 10-60 NM FROM 4 PM
SCA...PT ARENA TO PT REYES 0-10 NM FROM 1 PM
SCA...PT REYES TO PIGEON PT 0-10 NM FROM 4 PM
SCA...ROUGH BAR ADVISORY FOR SF BAR FROM 4 PM
&&
$$
PUBLIC FORECAST: BELL
AVIATION/MARINE: W PI
VISIT US AT WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
307 AM PST WED DEC 24 2014
...LOCALLY BLUSTERY CONDITIONS NEAR THE COAST AND IN THE HILLS TONIGHT
THROUGH CHRISTMAS MORNING...
...MUCH COOLER WEATHER BY CHRISTMAS DAY...
.SYNOPSIS...A COLD FRONT WILL SWEEP ACROSS THE REGION TODAY
LEADING TO AREAS OF LIGHT RAIN. BRISK NORTHWEST WINDS WILL DEVELOP
BEHIND THE COLD FRONT BY LATE IN THE AFTERNOON. LOCALLY STRONG
AND GUSTY WINDS WILL OCCUR ALONG THE COAST AND IN THE HILLS
TONIGHT INTO CHRISTMAS MORNING. OTHERWISE CHRISTMAS DAY WILL BE DRY AND
COOL WITH DRY WEATHER EXPECTED TO CONTINUE THROUGH NEXT WEEK.
FREEZING OVERNIGHT LOW TEMPERATURES ARE LIKELY FOR SOME INLAND
VALLEYS LATE IN THE WEEK AND INTO THE WEEKEND.
&&
.DISCUSSION...AS OF 3:00 AM PST WEDNESDAY...SIMILAR TO THE PAST
FEW MORNINGS PATCHY FOG HAS DEVELOPED ACROSS PORTIONS OF OUR
CWA...IN PARTICULAR OVER THE NORTH BAY PLUS AROUND SF BAY. SOME
REPORTS OF VERY LOW VISIBILITIES IN A FEW SPOTS. IN FACT OAKLAND
HAS DROPPED DOWN TO AN EIGHT OF A MILE AND A SPOTTER IN THE
BERKELEY AREA REPORTED VERY LOW VALUES AS WELL. OUTSIDE OF THE FOG
ALSO WORTH NOTING THAT TEMPS ARE RUNNING 2 TO 5 DEGREES COOLER
THAN YESTERDAY IN MOST SPOTS ALONG WITH DEW POINTS RUNNING ABOUT
THE SAME AMOUNT LOWER.
ONCE THE FOG BURNS OFF THE MAIN STORY FOR TODAY WILL BE A COLD
FRONT THAT WILL SWEEP THROUGH OUR AREA AND PROVIDE ANOTHER ROUND
OF RAIN ESPECIALLY FOR THE NORTHERN THIRD OF THE CWA. LATEST
GUIDANCE IN IS IN FAIRLY GOOD AGREEMENT THAT RAIN WILLS START OVER
THE NORTH BAY LATE IN THE MORNING TO EARLY AFTERNOON AND PROGRESS
DOWN TO THE SF BAY REGION OVER THE AFTERNOON AND THEN DISSIPATE BY
THE EVENING AS IT ENTERS THE MONTEREY BAY REGION. RAINFALL AMOUNTS
WILL BE VERY LIGHT COMPARED TO RECENT STORMS HOWEVER LOCALLY MORE
THAN A QUARTER OF AN INCH IS POSSIBLE ESPECIALLY ALONG THE COAST
FROM SAN MATEO COUNTY TO THE NORTH. URBAN LOCATIONS WILL LIKELY BE
CLOSER TO A TENTH OF AN INCH. WORTH NOTING THAT THE NEWEST RUN OF
THE HRRR JUST IN HAS BACKED OFF A BIT WITH THE QPF.
WHAT WILL LIKELY BE A BIGGER STORY OUT OF THE SYSTEM GOING THROUGH
TODAY WILL BE WIND AND COOLER TEMPERATURES. WINDS WILL PICK UP AS
THE FRONT GOES THROUGH AND COLDER AIR MOVES INTO THE AREA. 850 MB
SPEEDS PICK UP TO THE 35 TO 50 KT RANGE WITH MODEL SOUNDINGS
KEEPING THE STRONGER SPEEDS GENERALLY ABOVE THE 1000 FT LEVEL
SUGGESTING THAT THE BIGGEST IMPACTS WILL BE OVER THE HILLS. DUE TO
RECENT RAIN WOULD EXPECT TO GET REPORTS OF TREES BEING TOPPLED
ESPECIALLY FOR ANY SPOTS ALONG RIDGES THAT HAVE A NW EXPOSURE.
LOCAL GUSTS TO 40 MPH CAN BE EXPECTED ABOVE 2000 FEET.
TEMPERATURES WILL DECREASE BOTH DURING THE DAY AND AT NIGHT OVER
THE NEXT COUPLE OF DAYS AND MUCH COOLER AND DRIER AIR SETTLES
ACROSS THE CWA. BIGGEST CONCERN WILL BE THE OVERNIGHT LOWS
ESPECIALLY BY THURSDAY AND FRIDAY NIGHT. BOTH OF THESE WILL LIKELY
HAVE SOME OF OUR COOLEST READINGS IN QUITE SOME TIME WITH INTERIOR
SPOTS FORECAST TO DROP INTO THE 30S WITH EVEN SOME UPPER 20S NOT
OUT OF THE QUESTION. COASTAL SPOTS WILL STAY A BIT MILDER THANKS
IN LARGE PART TO SEA SURFACE TEMPERATURES STILL RUNNING WELL ABOVE
NORMAL.
THE COOLER AND DRY WEATHER WILL CONTINUE INTO NEXT WEEK AS THE
OVERALL FLOW REMAINS FROM THE NW. OUTSIDE OF THE CHANCE OF RAIN
TODAY NO SIGN OF PRECIPITATION OUT THROUGH NEXT FRIDAY.
&&
.AVIATION...AS OF 9:17 PM PST TUESDAY...LIGHT WINDS...CLEAR SKIES
AND RADIATIONAL COOLING TONIGHT WILL ALLOW AIR TEMPERATURES TO
COOL CLOSE TO THE DEWPOINT TEMPERATURES ONCE AGAIN. THEREFORE FOG
PATCHES MAY BE A LITTLE MORE EXTENSIVE IN COVERAGE BY EARLY
WEDNESDAY. IT`S A MODERATE TO HIGH CONFIDENCE VFR FORECAST FOR
THE EVENING BUT CONFIDENCE IN THE FORECASTS LOWERS LATE AT NIGHT
DUE TO POSSIBLE FOG DEVELOPMENT.
ON WEDNESDAY A FAST MOVING TROUGH ACCOMPANIED BY A COLD FRONTAL
PASSAGE WILL RESULT IN ENOUGH LIGHT RAIN TO PRODUCE WET RUNWAYS
AND THE POTENTIAL FOR AREAS OF GUSTY W-NW WINDS BY LATE MORNING
AND EARLY AFTERNOON. A BRIEF INCREASE IN THE WINDS IS ALSO
POSSIBLE WEDNESDAY OVER THE NORTH CENTRAL COAST.
VICINITY OF KSFO...VFR IS FORECAST THROUGH THE EVENING. SOME FOG
PATCHES ARE POSSIBLE BY EARLY WEDNESDAY. EARLIER COORDINATION WITH
CWSU OFFICE LED TO DECISION TO GO FORECAST TEMPO IFR CIGS 13Z-17Z
WITH CEILINGS RAPIDLY LIFTING TO MVFR BY MID-LATE MORNING. WEATHER
CHANGES ARE GOING TO BE RAPID WEDNESDAY AS THIS IS A QUICKLY MOVING
WEATHER SYSTEM.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...LOW TO MODERATE CONFIDENCE VFR HOLDS
FOR THE EVENING. LOCAL IFR INCREASINGLY LIKELY AFTER MIDNIGHT AS THE
SURFACE TEMPS COOL OFF AND LIGHT WINDS ALLOW FOR A FEW FOG PATCHES OR
LOW CEILINGS. CLOUDS INCREASE BY AFTERNOON WITH LIGHT RAIN ARRIVING
CLOSE TO 00Z.
&&
.MARINE...AS OF 3:00 AM PST WEDNESDAY...A FAST MOVING TROUGH AND COLD
FRONT WILL MOVE SOUTHEAST OVER THE AREA THIS AFTERNOON AND
EVENING. STRONG NORTHWEST WINDS WILL DEVELOP OVER THE COASTAL
WATERS TONIGHT AND THURSDAY AFTER THE FRONT PASSES WITH GALE FORCE
WINDS OVER THE OUTER WATERS.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...GLW...PT ARENA TO PT REYES 10-60 NM FROM 1 PM
GLW...PT REYES TO PIGEON PT 10-60 NM FROM 1 PM
GLW...PIGEON PT TO PT PINOS 10-60 NM FROM 4 PM
SCA...PT ARENA TO PT REYES 0-10 NM FROM 1 PM
SCA...PT REYES TO PIGEON PT 0-10 NM FROM 4 PM
SCA...ROUGH BAR ADVISORY FOR SF BAR FROM 4 PM
&&
$$
PUBLIC FORECAST: BELL
AVIATION: CANEPA
MARINE: W PI
VISIT US AT WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSBAYAREA
WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1017 AM EST WED DEC 24 2014
.DISCUSSION...
COLD FRONT AND PRECEDING SQUALL LINE WILL CONTINUE EASTWARD
THROUGH THE EASTERN GULF INTO LATE MORN AND AFT. PROJECTED MOTION
HAS THIS BAND REACHING LAKE/INLAND VOLUSIA COUNTIES TOWARD SUNSET
IF NOT A LITTLE AFTER INTO THE EARLY EVE. THIS TIMING MATCHES WELL
WITH LATEST HRRR AND LOCAL WRF MODEL TRENDS. WILL MAINTAIN POPS UP
TO 60-70% OVER THIS REGION FOR THE EXPECTED LATE DAY INCREASE IN
SHOWER/STORM COVERAGE. ELSEWHERE WILL KEEP CHANCE POPS IN THE
FORECAST AS IT IS NOT OUT OF THE QUESTION TO SEE SHOWERS OR A FEW
STORMS DEVELOP OUT AHEAD OF THIS MAIN LINE INTO THE AFTERNOON.
SUFFICIENT HEATING...DEWPOINTS IN THE UPPER 60S/LOW 70S AND STRONG
LOW/MID LEVEL WINDS WILL SUPPORT SOME STRONGER STORMS AS THIS
SQUALL LINE INITIALLY MOVES INTO THE REGION WITH THE MAIN THREAT
BEING STRONG TO ISOLATED SEVERE WIND GUSTS. CONVECTIVE BAND WILL
THEN WEAKEN AS IT GRADUALLY PUSHES SOUTHEAST ACROSS THE REGION
TONIGHT.
LOWER CLOUDS OVER NORTHERN AREAS WILL BREAK UP INTO LATE MORNING
WITH PARTLY CLOUDY SKIES EXPECTED FOR MUCH OF THE AFTERNOON.
BREEZY CONDS EXPECTED TODAY WITH HIGHS FORECAST TO REACH THE LOW
TO MID 80S.
&&
.AVIATION...LOW CLOUDS PRODUCING MVFR CIGS WILL BREAK UP INTO THE
LATE MORNING WITH VFR CONDS GENERALLY EXPECTED INTO MUCH OF THE
AFTERNOON. BREEZY SOUTHERLY WINDS EXPECTED TODAY WITH SUSTAINED
WINDS 15-18 KTS AND GUSTS 20-25 KTS.
APPROACHING SQUALL LINE OVER THE EASTERN GULF NOT EXPECTED TO
REACH LAKE COUNTY UNTIL AFT 21-22Z. TEMPO IFR/MVFR CONDS WILL
OCCUR WITH THIS BAND OF SHOWERS/STORMS AS IT SHIFTS SOUTHEAST AND
WEAKENS INTO TONIGHT. HOWEVER AS BAND INITIALLY PUSHES INTO AREAS
ALONG AND WEST OF I-4 STRONG WIND GUSTS WILL BE POSSIBLE WITH ANY
STORMS.
&&
.MARINE...
TODAY-TONIGHT...POOR TO HAZARDOUS BOATING CONDITIONS WILL CONTINUE
OVER THE COASTAL WATERS OUT AHEAD OF AN APPROACHING COLD FRONT AND
PRECEDING BAND OF CONVECTION. SOUTHERLY WINDS UP TO 15-20 KNOTS
NEARSHORE AND AROUND 20 KNOTS OFFSHORE WITH SEAS UP TO 5 TO 6
FEET. THE SMALL CRAFT ADVISORY FOR WINDS WILL CONTINUE INTO THIS
EVENING WITH SMALL CRAFT EXERCISE CAUTION HEADLINES STILL NEEDED
NEARSHORE.
BAND OF CONVECTION WILL MOVE INTO THE COASTAL WATERS THIS EVENING
AND OVERNIGHT AND MAY BE ABLE TO PRODUCE STRONG GUSTY WINDS AS
THEY MOVE OFFSHORE. SOUTH TO SOUTHWEST WINDS BECOME NORTHWEST
TOWARD SUNRISE AS THE FRONTAL LINE MOVES DOWN THE PENINSULA.
BORDERLINE SCA/SCEC CONDITIONS EXPECTED OVERNIGHT OFFSHORE.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 PM EST THIS EVENING FOR
WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20
TO 60 NM OFFSHORE-WATERS FROM SEBASTIAN INLET TO JUPITER
INLET 20 TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD
COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE.
&&
$$
WEITLICH/CRISTALDI
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1103 AM EST WED DEC 24 2014
.UPDATE...
ISSUED AT 1103 AM EST WED DEC 24 2014
THE COLD FRONT IS CURRENTLY ALIGNED FROM IN/OH BORDER DOWN THROUGH
NEAR CENTRAL KENTUCKY...HAVING JUST PASSED THROUGH BWG...BUT STILL
SLIGHTLY WEST OF SDF. PLENTY OF SHOWER ACTIVITY IS FILLING IN ALONG
AND BEHIND THE FRONT...AND HAVE BEEFED UP POPS TO LIKELY FOR MOST AS
IT MAKES IT WAY TOWARDS EASTERN KENTUCKY THIS AFTERNOON. ALSO ADDED A
FEW MORE COUNTIES TO THE WIND ADVISORY...MAINLY HIGHLIGHTING
ELEVATIONS ABOVE 1500 FEET...CLOSER TO THE STRONGER WINDS OCCURRING
ALOFT. SPC STILL HIGHLIGHTS A MARGINAL THREAT OF STRONGER WIND GUSTS
ASSOCIATED WITH MORE INTENSE SHOWERS OR ISOLATED THUNDERSTORMS...SO
WILL CONTINUE TO ADVERTISE THIS POSSIBILITY ACROSS MUCH OF THE AREA
AS WELL IN THE HWO. UPDATES HAVE BEEN SENT.
UPDATE ISSUED AT 648 AM EST WED DEC 24 2014
UPDATED TO LOWER POPS THIS MORNING AS SOUTHEAST FLOW CONTINUES TO
STRENGTHEN WITH CLOUD HEIGHTS CONTINUING TO GO UP. THEY ARE NOW OVER
10KFT. THUS...CHANCES FOR MEASURABLE RAIN ARE DECREASING THROUGH THE
MORNING HOURS. BEST CHANCE OF RAIN STILL LOOKS TO COME WITH THE COLD
FRONT AS IT CROSSES THE AREA THIS AFTERNOON. LATEST HI-RES MODELS
CONTINUE TO SHOW THE POSSIBILITY OF A FEW THUNDERSTORMS AS THE FRONT
PUSHES ACROSS OUR AREA. SHOULD WARM UP NICELY GIVEN THE SOUTHEAST
FLOW AND LIMITED LOW CEILINGS THIS MORNING. WOULDN`T BE SURPRISED TO
SEE US GET EVEN WARMER THAN THE FORECAST CURRENTLY REFLECTS.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 316 AM EST WED DEC 24 2014
AREA OF LOW PRESSURE IS NOW STARTING TO MAKE ITS MOVE NORTH ACROSS
CENTRAL KENTUCKY...AND WILL END UP OVER SOUTHEAST MICHIGAN BY THIS
EVENING. STRONG LIFT ASSOCIATED WITH THE LOW PRESSURE SYSTEM WILL
SPREAD ACROSS THE AREA THROUGH DAYBREAK WITH RAIN BECOMING WIDESPREAD
ONCE AGAIN AFTER A BRIEF LULL OVER THE PAST FEW HOURS. HRRR AND RAP
ARE IN GOOD AGREEMENT THAT THIS LIFT WILL EXIT TO THE NORTH BY 9 OR
10 AM...WITH ANOTHER LULL IN PRECIPITATION EXPECTED THROUGH MIDDAY.
WITH THE MIDDAY LULL IN PRECIPITATION...HIGHS WILL WARM INTO THE 60S
FOR ONE MORE DAY.
FINALLY AS THE LOW SHIFTS NORTH THOUGH...A STRONG COLD FRONT WILL
PUSH EAST ACROSS THE AREA THIS AFTERNOON. WITH THE MILD
TEMPERATURES...WE MAY GENERATE SOME WEAK INSTABILITY TO SUPPORT
CONVECTIVE SHOWERS DEVELOPING ALONG THE FRONT AS IT PUSHES ACROSS THE
AREA. WHILE THUNDER CHANCES REMAIN LOW...CANNOT RULE OUT SOME THUNDER
WITH THE STRONGER CELLS...ESPECIALLY ACROSS NORTHERN KENTUCKY. GIVEN
THE ABUNDANCE OF MID LEVEL DRY AIR...AND STRONG 850MB WINDS AROUND 45
KNOTS...WE COULD SEE THE POTENTIAL FOR SOME HIGHER WINDS TO GET MIXED
DOWN WITH THE SHOWERS. HOWEVER...EVEN WITHOUT THE CONVECTIVE SUPPORT
FOR WINDS...THE SYNOPTIC SETUP BEHIND THE FRONT SHOULD SUPPORT 40+
MPH WINDS...ESPECIALLY ACROSS THE NORTHERN HALF OF THE AREA.
THUS...WILL GO AHEAD WITH A WIND ADVISORY FOR THE NORTHERN HALF OF
THE AREA. CONDITIONS ARE MORE MARGINAL FARTHER SOUTH...BUT A WIND
ADVISORY FOR THE HIGH TERRAIN NEAR THE VIRGINIA BORDER ALSO SEEMS IN
ORDER GIVEN THE STRONG WINDS AT 850MB. BEST THREAT FOR THE HIGHER
WINDS WILL BE AFTER 17Z AND BEFORE 03Z TONIGHT.
CONDITIONS WILL QUITE DOWN SOME THIS EVENING AS SUBSIDENCE SPREADS IN
BEHIND THE DEPARTING FRONT. HOWEVER...A SHORTWAVE TROUGH WILL PUSH
EAST ACROSS THE AREA LATE TONIGHT...WITH THE MOISTURE DEPTH
INCREASING TO SUPPORT SOME LIGHT RAIN/DRIZZLE. COLDER AIR WILL ALSO
BE SPILLING INTO THE AREA TONIGHT BEHIND THE FRONT. WHILE MOST AREAS
WILL STAY MILD ENOUGH FOR JUST RAIN...THE HIGHER TERRAIN IN THE
SOUTHEAST WILL SUPPORT SOME SNOW CHANCES. IN FACT...CONDITIONS ALIGN
GOOD ENOUGH TONIGHT WE COULD SEE A LIGHT COATING OF SNOW ON THE HIGH
TERRAIN ABOVE 2500 FEET LATE TONIGHT.
HEIGHTS WILL BE QUICK TO BUILD BACK ACROSS THE AREA ON CHRISTMAS.
CLOUDS MAY BE STUBBORN THROUGH THE FIRST HALF OF THE DAY...BUT WE
SHOULD DEFINITELY SEE A DECREASING TREND THROUGH THE AFTERNOON AND
EVENING AS THE RIDGE CENTERS ITSELF OVER THE REGION. HIGHS WILL
STRUGGLE TO WARM GIVEN THE ABUNDANCE OF CLOUDS THROUGH THE FIRST HALF
OF THE DAY...SO PLAN TO KEEP HIGHS LIMITED TO THE LOW TO MID 40S WITH
30S ON THE HIGHER TERRAIN IN THE SOUTHEAST.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 420 AM EST WED DEC 24 2014
THE PERIOD IS EXPECTED TO BEGIN WITH A CLOSED UPPER LOW CONTINUING TO
DEPART TO THE NORTHEAST OF THE REGION WITH UPPER LEVEL RIDGING
BUILDING ACROSS THE AREA AT THE START OF THE PERIOD. FURTHER TO THE
WEST A TROUGH IS EXPECTED TO EXTEND FROM THE NORTHERN PLAINS SOUTH
INTO THE SOUTHERN ROCKIES AND NORTHERN MEXICO. SFC AND UPPER LEVEL
RIDGING WILL GRADUALLY WORK ACROSS THE AREA FOR THU NIGHT INTO FRIDAY
AND THEN DEPART TO THE EAST FRIDAY NIGHT INTO SATURDAY. MEANWHILE A
SHORTWAVE TROUGH IS ANTICIPATED TO EJECT FROM THE WESTERN TROUGH
ACROSS THE PLAINS TOWARD THE GREAT LAKES FROM FRIDAY INTO SATURDAY.
THIS WILL LEAD TO GRADUALLY LOWERING HEIGHTS ACROSS THE GREAT LAKES
AND OH VALLEY AND A COLD FRONT DROPPING TOWARD THE REGION TO START
THE WEEKEND. THIS SHOULD BEGIN THE START OF AN UNSETTLED PERIOD.
OVER TIME...A RATHER BROAD TROUGH IS EXPECTED TO DEVELOP FROM CENTRAL
CANADA SOUTH INTO THE ROCKIES AND THEN EAST INTO THE EASTERN CONUS.
MODELS VARY FROM RUN TO RUN AND MODEL TO MODEL WITH THE HANDLING OF
INDIVIDUAL SHORTWAVES IN WEST SOUTH TO SOUTHWEST FLOW DURING THIS
PERIOD AND THE INTERACTION WITH A BAROCLINIC ZONE...THE FRONT THAT
MOVES INTO THE AREA EARLY IN THE WEEKEND...RESULTING IN SFC WAVES
DEVELOPING ALONG THE FRONT. THE ECMWF IS GENERALLY SLOWER BRINGING
THIS FRONT ACROSS THE AREA AND IS ALSO STRONGER AND FURTHER SOUTHEAST
WITH A SFC WAVE SUN NIGHT INTO MONDAY. AS THIS LAST SYSTEM DEPARTS AN
ARCTIC BOUNDARY SHOULD APPROACH THE AREA TUE OR WED.
DUE TO AN OVERALL LACK OF COLDER AIR FOR MOST OF THE PERIOD...MUCH OF
THE PRECIPITATION SHOULD FALL AS RAIN...ALTHOUGH SOME SNOW MAY MIX IN
ON SUNDAY NIGHT INTO EARLY ON MONDAY IN THE HIGHEST TERRAIN AND NORTH
OF THE MTN PARKWAY. A MIX OF RAIN AND SNOW WILL REMAIN POSSIBLE INTO
THE DAY ON TUESDAY AS WE HELD ONTO SLIGHT CHANCE POPS TO ACCOUNT FOR
THE ECMWF RUN. BOTH THE GFS AND ECMWF RUNS SUPPORT A WET END TO THE
WEEKEND.
AS FOR TEMPERATURES...THE PATTERN FAVORS A RIDGE VALLEY TEMPERATURE
SPLIT ON THU NIGHT AS SKIES WILL HAVE CLEARED OR SHOULD BE CLEARING
AS SFC AND UPPER LEVEL RIDGING WORK INTO THE AREA. A RELATIVELY DRY
AIR MASS AND A DOWNSLOPE COMPONENT SHOULD LEAD TO A RATHER MILD DAY
ON FRIDAY...ESPECIALLY FOR VALLEYS NEAR THE VA BORDER. THE DEPARTING
RIDGE SHOULD AGAIN FAVOR MILDER LOWS ON FRI NIGHT...BUT YET ANOTHER
RIDGE/VALLEY SPLIT. SATURDAY SHOULD AGAIN BE MILD AHEAD OF THE
BOUNDARY. WITH THE BAROCLINIC ZONE OVER OR NEAR THE REGION A
GENERALLY NW TO SOUTH OR SOUTHEAST GRADIENT IN TEMPERATURES IS
ANTICIPATED FOR THE REMAINDER OF THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 648 AM EST WED DEC 24 2014
DRY AIR HAS INVADED THE AREA THANKS TO SOUTHEAST DOWNSLOPING FLOW OFF
THE HIGH TERRAIN. THIS HAS PUSHED CEILINGS UP TO OVER 10KFT. THIS
SHOULD REMAIN THE CASE THIS MORNING. COLD FRONT WILL BRING LOWER CIGS
LATER THIS AFTERNOON AND EVENING...EVENTUALLY REACHING MVFR LATE THIS
AFTERNOON. SOME SHOWERS WILL STILL BE POSSIBLE AS THE FRONT CROSSES
THE AREA. THE BIGGER STORY WILL BE THE POTENTIAL FOR STRONG GUSTY
WINDS AS THE FRONT BLOWS ACROSS HERE TODAY. WIND GUSTS UP TO 40 KNOTS
WILL BE POSSIBLE WITH THE HIGHEST READINGS EXPECTED ACROSS NORTHERN
KENTUCKY. WINDS WILL SLOWLY SUBSIDE THIS EVENING...BUT SHOULD REMAIN
SOMEWHAT GUSTY THROUGH THE NIGHT. A CHANCE OF RAIN WILL RETURN LATE
TONIGHT AS DEEPER MOISTURE SPREADS ACROSS THE AREA.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR KYZ044-050>052-
058>060-068-069-088-104-106>120.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...KAS
LONG TERM...JP
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
648 AM EST WED DEC 24 2014
.UPDATE...
ISSUED AT 648 AM EST WED DEC 24 2014
UPDATED TO LOWER POPS THIS MORNING AS SOUTHEAST FLOW CONTINUES TO
STRENGTHEN WITH CLOUD HEIGHTS CONTINUING TO GO UP. THEY ARE NOW OVER
10KFT. THUS...CHANCES FOR MEASURABLE RAIN ARE DECREASING THROUGH THE
MORNING HOURS. BEST CHANCE OF RAIN STILL LOOKS TO COME WITH THE COLD
FRONT AS IT CROSSES THE AREA THIS AFTERNOON. LATEST HI-RES MODELS
CONTINUE TO SHOW THE POSSIBILITY OF A FEW THUNDERSTORMS AS THE FRONT
PUSHES ACROSS OUR AREA. SHOULD WARM UP NICELY GIVEN THE SOUTHEAST
FLOW AND LIMITED LOW CEILINGS THIS MORNING. WOULDN`T BE SURPRISED TO
SEE US GET EVEN WARMER THAN THE FORECAST CURRENTLY REFLECTS.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 316 AM EST WED DEC 24 2014
AREA OF LOW PRESSURE IS NOW STARTING TO MAKE ITS MOVE NORTH ACROSS
CENTRAL KENTUCKY...AND WILL END UP OVER SOUTHEAST MICHIGAN BY THIS
EVENING. STRONG LIFT ASSOCIATED WITH THE LOW PRESSURE SYSTEM WILL
SPREAD ACROSS THE AREA THROUGH DAYBREAK WITH RAIN BECOMING WIDESPREAD
ONCE AGAIN AFTER A BRIEF LULL OVER THE PAST FEW HOURS. HRRR AND RAP
ARE IN GOOD AGREEMENT THAT THIS LIFT WILL EXIT TO THE NORTH BY 9 OR
10 AM...WITH ANOTHER LULL IN PRECIPITATION EXPECTED THROUGH MIDDAY.
WITH THE MIDDAY LULL IN PRECIPITATION...HIGHS WILL WARM INTO THE 60S
FOR ONE MORE DAY.
FINALLY AS THE LOW SHIFTS NORTH THOUGH...A STRONG COLD FRONT WILL
PUSH EAST ACROSS THE AREA THIS AFTERNOON. WITH THE MILD
TEMPERATURES...WE MAY GENERATE SOME WEAK INSTABILITY TO SUPPORT
CONVECTIVE SHOWERS DEVELOPING ALONG THE FRONT AS IT PUSHES ACROSS THE
AREA. WHILE THUNDER CHANCES REMAIN LOW...CANNOT RULE OUT SOME THUNDER
WITH THE STRONGER CELLS...ESPECIALLY ACROSS NORTHERN KENTUCKY. GIVEN
THE ABUNDANCE OF MID LEVEL DRY AIR...AND STRONG 850MB WINDS AROUND 45
KNOTS...WE COULD SEE THE POTENTIAL FOR SOME HIGHER WINDS TO GET MIXED
DOWN WITH THE SHOWERS. HOWEVER...EVEN WITHOUT THE CONVECTIVE SUPPORT
FOR WINDS...THE SYNOPTIC SETUP BEHIND THE FRONT SHOULD SUPPORT 40+
MPH WINDS...ESPECIALLY ACROSS THE NORTHERN HALF OF THE AREA.
THUS...WILL GO AHEAD WITH A WIND ADVISORY FOR THE NORTHERN HALF OF
THE AREA. CONDITIONS ARE MORE MARGINAL FARTHER SOUTH...BUT A WIND
ADVISORY FOR THE HIGH TERRAIN NEAR THE VIRGINIA BORDER ALSO SEEMS IN
ORDER GIVEN THE STRONG WINDS AT 850MB. BEST THREAT FOR THE HIGHER
WINDS WILL BE AFTER 17Z AND BEFORE 03Z TONIGHT.
CONDITIONS WILL QUITE DOWN SOME THIS EVENING AS SUBSIDENCE SPREADS IN
BEHIND THE DEPARTING FRONT. HOWEVER...A SHORTWAVE TROUGH WILL PUSH
EAST ACROSS THE AREA LATE TONIGHT...WITH THE MOISTURE DEPTH
INCREASING TO SUPPORT SOME LIGHT RAIN/DRIZZLE. COLDER AIR WILL ALSO
BE SPILLING INTO THE AREA TONIGHT BEHIND THE FRONT. WHILE MOST AREAS
WILL STAY MILD ENOUGH FOR JUST RAIN...THE HIGHER TERRAIN IN THE
SOUTHEAST WILL SUPPORT SOME SNOW CHANCES. IN FACT...CONDITIONS ALIGN
GOOD ENOUGH TONIGHT WE COULD SEE A LIGHT COATING OF SNOW ON THE HIGH
TERRAIN ABOVE 2500 FEET LATE TONIGHT.
HEIGHTS WILL BE QUICK TO BUILD BACK ACROSS THE AREA ON CHRISTMAS.
CLOUDS MAY BE STUBBORN THROUGH THE FIRST HALF OF THE DAY...BUT WE
SHOULD DEFINITELY SEE A DECREASING TREND THROUGH THE AFTERNOON AND
EVENING AS THE RIDGE CENTERS ITSELF OVER THE REGION. HIGHS WILL
STRUGGLE TO WARM GIVEN THE ABUNDANCE OF CLOUDS THROUGH THE FIRST HALF
OF THE DAY...SO PLAN TO KEEP HIGHS LIMITED TO THE LOW TO MID 40S WITH
30S ON THE HIGHER TERRAIN IN THE SOUTHEAST.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 420 AM EST WED DEC 24 2014
THE PERIOD IS EXPECTED TO BEGIN WITH A CLOSED UPPER LOW CONTINUING TO
DEPART TO THE NORTHEAST OF THE REGION WITH UPPER LEVEL RIDGING
BUILDING ACROSS THE AREA AT THE START OF THE PERIOD. FURTHER TO THE
WEST A TROUGH IS EXPECTED TO EXTEND FROM THE NORTHERN PLAINS SOUTH
INTO THE SOUTHERN ROCKIES AND NORTHERN MEXICO. SFC AND UPPER LEVEL
RIDGING WILL GRADUALLY WORK ACROSS THE AREA FOR THU NIGHT INTO FRIDAY
AND THEN DEPART TO THE EAST FRIDAY NIGHT INTO SATURDAY. MEANWHILE A
SHORTWAVE TROUGH IS ANTICIPATED TO EJECT FROM THE WESTERN TROUGH
ACROSS THE PLAINS TOWARD THE GREAT LAKES FROM FRIDAY INTO SATURDAY.
THIS WILL LEAD TO GRADUALLY LOWERING HEIGHTS ACROSS THE GREAT LAKES
AND OH VALLEY AND A COLD FRONT DROPPING TOWARD THE REGION TO START
THE WEEKEND. THIS SHOULD BEGIN THE START OF AN UNSETTLED PERIOD.
OVER TIME...A RATHER BROAD TROUGH IS EXPECTED TO DEVELOP FROM CENTRAL
CANADA SOUTH INTO THE ROCKIES AND THEN EAST INTO THE EASTERN CONUS.
MODELS VARY FROM RUN TO RUN AND MODEL TO MODEL WITH THE HANDLING OF
INDIVIDUAL SHORTWAVES IN WEST SOUTH TO SOUTHWEST FLOW DURING THIS
PERIOD AND THE INTERACTION WITH A BAROCLINIC ZONE...THE FRONT THAT
MOVES INTO THE AREA EARLY IN THE WEEKEND...RESULTING IN SFC WAVES
DEVELOPING ALONG THE FRONT. THE ECMWF IS GENERALLY SLOWER BRINGING
THIS FRONT ACROSS THE AREA AND IS ALSO STRONGER AND FURTHER SOUTHEAST
WITH A SFC WAVE SUN NIGHT INTO MONDAY. AS THIS LAST SYSTEM DEPARTS AN
ARCTIC BOUNDARY SHOULD APPROACH THE AREA TUE OR WED.
DUE TO AN OVERALL LACK OF COLDER AIR FOR MOST OF THE PERIOD...MUCH OF
THE PRECIPITATION SHOULD FALL AS RAIN...ALTHOUGH SOME SNOW MAY MIX IN
ON SUNDAY NIGHT INTO EARLY ON MONDAY IN THE HIGHEST TERRAIN AND NORTH
OF THE MTN PARKWAY. A MIX OF RAIN AND SNOW WILL REMAIN POSSIBLE INTO
THE DAY ON TUESDAY AS WE HELD ONTO SLIGHT CHANCE POPS TO ACCOUNT FOR
THE ECMWF RUN. BOTH THE GFS AND ECMWF RUNS SUPPORT A WET END TO THE
WEEKEND.
AS FOR TEMPERATURES...THE PATTERN FAVORS A RIDGE VALLEY TEMPERATURE
SPLIT ON THU NIGHT AS SKIES WILL HAVE CLEARED OR SHOULD BE CLEARING
AS SFC AND UPPER LEVEL RIDGING WORK INTO THE AREA. A RELATIVELY DRY
AIRMASS AND A DOWNSLOPE COMPONENT SHOULD LEAD TO A RATHER MILD DAY ON
FRIDAY...ESPECIALLY FOR VALLEYS NEAR THE VA BORDER. THE DEPARTING
RIDGE SHOULD AGAIN FAVOR MILDER LOWS ON FRI NIGHT...BUT YET ANOTHER
RIDGE/VALLEY SPLIT. SATURDAY SHOULD AGAIN BE MILD AHEAD OF THE
BOUNDARY. WITH THE BAROCLINIC ZONE OVER OR NEAR THE REGION A GENERALLY
NW TO SOUTH OR SOUTHEAST GRADIENT IN TEMPERATURES IS ANTICIPATED FOR
THE REMAINDER OF THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 648 AM EST WED DEC 24 2014
DRY AIR HAS INVADED THE AREA THANKS TO SOUTHEAST DOWNSLOPING FLOW OFF
THE HIGH TERRAIN. THIS HAS PUSHED CEILINGS UP TO OVER 10KFT. THIS
SHOULD REMAIN THE CASE THIS MORNING. COLD FRONT WILL BRING LOWER CIGS
LATER THIS AFTERNOON AND EVENING...EVENTUALLY REACHING MVFR LATE THIS
AFTERNOON. SOME SHOWERS WILL STILL BE POSSIBLE AS THE FRONT CROSSES
THE AREA. THE BIGGER STORY WILL BE THE POTENTIAL FOR STRONG GUSTY
WINDS AS THE FRONT BLOWS ACROSS HERE TODAY. WIND GUSTS UP TO 40 KNOTS
WILL BE POSSIBLE WITH THE HIGHEST READINGS EXPECTED ACROSS NORTHERN
KENTUCKY. WINDS WILL SLOWLY SUBSIDE THIS EVENING...BUT SHOULD REMAIN
SOMEWHAT GUSTY THROUGH THE NIGHT. A CHANCE OF RAIN WILL RETURN LATE
TONIGHT AS DEEPER MOISTURE SPREADS ACROSS THE AREA.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON TODAY TO 10 PM EST THIS EVENING FOR
KYZ044-050>052-058>060-068-069-088-104-106>112-114-118>120.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM...JP
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
723 AM EST WED DEC 24 2014
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTHWARD THROUGH THE AREA THROUGH THIS
MORNING AS A LOW PRESSURE SYSTEM STRENGTHENS WEST OF THE MOUNTAINS.
AN ASSOCIATED COLD FRONT WILL CROSS THE AREA TONIGHT. HIGH PRESSURE
BUILDS BACK IN FROM THE SOUTHWEST CHRISTMAS DAY THROUGH FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
A DYNAMIC SYSTEM CONTINUES TO DEVELOP OVER THE CENTRAL GULF COAST
STATES AND TENNESSEE VALLEY EARLY THIS MORNING. LOCALLY...A RESIDUAL
COOL-WEDGE AIRMASS LINGERS WITH TEMPERATURES IN THE MID/UPPER 40S
W OF THE BAY. A WARM FRONT/COASTAL FRONT IS MOVING ONSHORE WITH
TEMPERATURES RISING INTO THE LOW/MID 60S OVER COASTAL SE VA AND NE
NC. THE FIRST BATCH OF RA HAS LIFTED NE OF THE LOCAL AREA. VSBYS
HAVE FALLEN IN THE WAKE OF THAT BATCH OF RA. THE LOWEST VSBYS ARE
ON THE COOL SIDE OF THE BOUNDARY FROM SOUTH CENTRAL VA ACROSS THE
HAMPTON ROADS AND INTERIOR NE NC. AN SPS HAS BEEN ISSUED TO
ACCOUNT FOR THIS. VSBY SHOULD RISE AS THE NEXT BATCH OF RAIN
ARRIVES FROM THE SW. DENSE FOG IS LIKELY TO DEVELOP OVER THE
WATER OVER THE NEXT FEW HOURS AS A WARM/MOIST AIRMASS OFF THE GULF
STREAM OVERSPREADS COOLER WATER.
THE NEXT BATCH OF RA WILL OVERSPREAD THE REGION THROUGH THE MORNING.
THE WARM FRONT SHOULD STEADILY LIFT SE-NW ACROSS THE COASTAL PLAIN
AND INTO THE I-95 CORRIDOR THIS MORNING AS THE LOW DEEPENS TO THE
W AND TRACKS NNE INTO THE OHIO VALLEY. A BLEND OF THE HI-RES ARW
AND HRRR RESULTS IN TEMPERATURES RISING INTO THE MID 60S TO NEAR
70 BY MIDDAY ROUGHLY ALONG AND E OF AN AVC-RIC-CGE LINE...WITH THE
WEDGE AIRMASS HOLDING STRONG OVER THE NW PIEDMONT.
PERIODS OF RA SHOULD CONTINUE THROUGH THE AFTERNOON. AS TEMPERATURES
AND DEWPOINTS RISE THERE IS A CHC OF THUNDER BY AFTERNOON WHEN
COMBINED WITH A STRONG SYSTEM TO THE W. CLOUDS/RA SHOULD LIMIT
DESTABILIZATION...SO SPC HAS ONLY THE SE PORTION OF THE AREA IN A
MARGINAL SEVERE RISK DESPITE A WARM MOISTURE RICH AIRMASS AND A
STRONG 925-700MB WIND FIELD. BY LATE AFTERNOON HIGHS SHOULD RANGE
FROM THE MID/UPPER 60S FOR CENTRAL PORTIONS TO AROUND 70 SE...WITH
MID/UPPER 50S OVER THE FAR NW PIEDMONT. HIGHS WILL BE NEAR
RECORDS...SEE THE CLIMATE SECTION BELOW FOR DETAILS.
THE COLD FRONT ARRIVES FROM THE W THIS EVENING AND MOVES W-E ACROSS
THE AREA AFTER MIDNIGHT. HIGH POPS CONTINUE THROUGH THE
EVENING...AND THEN RAPIDLY DIMINISH AFTER MIDNIGHT. A MENTION OF
THUNDER WILL BE MAINTAINED FOR THE AREA THROUGH THE EVENING...AND
THROUGH THE EARLY OVERNIGHT HOURS FOR COASTAL PORTIONS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
DRIER AIR ARRIVES CHRISTMAS MORNING AS HIGH PRESSURE BUILDS IN FROM
THE W. A SLOWER FRONTAL PASSAGE WILL RESULT IN A MILD CHRISTMAS
MORNING WITH LOWS RANGING FROM THE MID 40S FAR W...TO THE MID/UPPER
50S SE. THE SKY SHOULD BECOME MAINLY SUNNY WITH SCT AFTERNOON CU
ALONG WITH BREEZY WESTERLY FLOW BY MID/LATE MORNING CHRISTMAS DAY.
HIGHS SHOULD RANGE FROM THE MID 50S TO LOWER 60S CHRISTMAS DAY AS
CAA IS WEAK AND WILL BE OFFSET BY DOWNSLOPE WARMING (AND DUE TO A
WARM BEGINNING).
CLEAR/SEASONABLE THURSDAY NIGHT WITH LOWS IN THE UPPER 20S TO MID
30S. SURFACE HIGH PRESSURE SETTLES IMMEDIATELY OFF THE COAST FRIDAY
RESULTING IN LIMITED MIXING/LIGHT WINDS AND SUNNY CONDITIONS. HIGHS
SHOULD GENERALLY BE IN THE 50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE MODELS ARE IN GOOD AGREEMENT TO BEGIN THE PERIOD FRIDAY NIGHT
WITH THE STRONG RIDGING OVER THE SOUTHEASTERN US AND HIGH PRESSURE
OVER THE SOUTHEAST...CENTERED OVER EASTERN VA/NC. BUT THE MODELS
STRUGGLE WITH THE BREAKING DOWN OF THE RIDGE WITH THE GFS BREAKING
IT DOWN MUCH MORE QUICKLY THAN THE ECMWF. THE GFS ALLOW THE NEXT
COLD FRONT TO DROP INTO THE ARE SAT NIGHT AND MOVES IT SOUTH OF
THE REGION BY SUNDAY MORNING...SETTING UP AN OVERRUNNING PATTERN
SUNDAY AFTERNOON INTO MONDAY MORNING. THE ECMWF...AND THE 12Z IS
FURTHER NORTH WITH FEATURES THAN 00Z RUN...KEEPS THE RIDGE MUCH
STRONGER OVER THE SE AND DOES NOT ALLOW THE COLD FRONT TO MOVE
THROUGH THE AREA SAT NIGHT. IT STALLS THE FRONT OVER THE AREA ON
SUNDAY AND AS A WAVE OF LOW PRESSURE FORMS ALONG THE BOUNDARY AND
LIFTS NE INTO THE CENTRAL APPALACHIANS...IT PUSHES GULF MOISTURE
INTO THE AREA. THE 00Z ECMWF PUSHED THE WAVE OFF THE COAST BY
MONDAY...BUT THE 12Z RUN LIFTS THE LOW TO THE NORTH AND DRAGS A
COLD FRONT ACROSS THE REGION ON TUESDAY.
SO FOR NOW WITH THE GREAT SPREAD IN THE MODELS...HAVE TRENDED
TOWARD HPC/WPC GUIDANCE...WHICH IS SIMILAR TO THE 00Z ECMWF AND
BROUGHT THE WAVE INTO THE REGION ON SUNDAY AFTERNOON AND EVENING
WITH IT EXITING BY MONDAY AFTERNOON. HAVE INCREASED POPS TO 50%
FOR THAT PERIOD...KEEPING SATURDAY DRY. HAVE ALSO GONE DRY ON
MONDAY NIGHT INTO TUESDAY. THE BIG DIFFERENCE COMES TO
TEMPERATURES AS THE GFS WOULD ALLOW MUCH COLD AIR INTO THE REGION
BEGINNING ON SUNDAY THROUGH TUESDAY. THIS COULD ALSO POTENTIALLY
LEAD TO SOME WINTRY PCPN WITH WAVE ON SUNDAY NIGHT. FOR NOW HAVE
KEPT TEMPERATURES ABOVE FREEZING AND ALL RAIN WITH THE COLD AIR
BEING KEPT MORE TO THE NORTH. FOR TEMPERATURES HAVE ALLOW FOR A
GRADUAL COOL DOWN THROUGH THE PERIOD WITH THE COLDEST AIR ARRIVING
ON TUESDAY WITH HIGHS IN THE 40S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...ANOTHER BAND OF RAIN WAS PROGRESSING INTO THE CWA FROM
THE SW. CIGS AND VSBYS WILL CONTINUE TO BE VARIABLE BUT ARE
EXPECTED TO BE PREDOMINANTLY IFR OR LOWER THIS MORNING. A BIT OF
IMPROVEMENT IS EXPECTED THIS AFTERNOON AS THE AREA BECOMES WARM
SECTORED BUT THE TAF SITES SHOULD BE MAINLY IFR IS STILL EXCEPT AT
ORF AND ECG. CONFIDENCE IN THE DEGREE OF IMPROVEMENT IS MARGINAL.
A COLD FRONT APPROACHES FROM THE WEST TONIGHT WITH SHOWERS AND A
SLGT CHC OF THUNDER (THIS PCPN NOT INCLUDED IN THE TAF).
CONDITIONS IMPROVE FROM THE WEST IN THE MORNING AS WINDS TURN TO
WESTERLY.
OUTLOOK...HIGH PRESSURE DOMINATES THURSDAY AFTERNOON THROUGH
SATURDAY WITH DRY WEATHER. A CHC FOR RAIN RETURNS SUNDAY AS LOW
PRESSURE APPROACHES FROM THE WEST.
&&
.MARINE...
DENSE FOG ADVISORY IS IN EFFECT FOR THE MARINE AREA THROUGH LATE
THIS AFTERNOON AS WARM MOIST AIR MOVES OVER THE RELATIVELY COOL
WATERS.
AS OF 11Z...WINDS WERE BEGINNING TO INCREASE FROM THE SE. SCA
STARTED AT 15Z FOR THE MOUTH OF THE BAY AS WAVES WILL SOON REACH 4
FT IN THE CHANNEL.
PREVIOUS DISCUSSION...
AS OF 08Z...WINDS REMAIN LIGHT OVER THE MARINE AREA BUT ARE FORECAST
TO INCREASE FROM THE SE AND THEN S THIS MORNING AS A WARM FRONT
MOVES N THROUGH THE WATERS AND LOW PRESSURE DEEPENS OVER THE OHIO
VALLEY. SCA IS IN EFFECT FOR ALL THE WATERS EXCEPT THE RIVERS SAVE
THE LOWER JAMES. SCA CONDITIONS OVER INLAND WATERS MAY BE MINIMAL
AT FIRST DUE TO LIMITED MIXING BUT WILL BECOME MORE FAVORABLE
THURSDAY MORNING. HAVE ADDED THE LOWER JAMES WITH TIMES STAGGERED
SLIGHTLY FROM THE BAY (STARTING AT 21Z TODAY AND ENDING 3 HOURS
EARLIER THURSDAY). LATER SHIFTS MAY NEED TO CONSIDER SCA BEHIND
THE COLD FRONT FOR OTHER RIVER ZONES ON THURSDAY MORNING.
SCA IS ALREADY IN EFFECT N OF PARRAMORE ISLAND. SEAS ARE EXPECTED TO
BUILD TO 5 FT OR HIGHER BY 18Z S OF THERE AND DECIDED TO BEGIN SCA S
OF PARRAMORE ISLAND AT 15Z TO ALLOW SUFFICIENT CUSHION.
HIGH PRESSURE THEN BUILDS INTO THE REGION ON THURSDAY NIGHT AND
LINGERS THROUGH SATURDAY AS A STRONG UPPER LEVEL RIDGE BUILDS INTO
THE SOUTHEASTERN US AND KEEPS STRONG HIGH PRESSURE AT THE SURFACE
OVER THE REGION THROUGH SATURDAY. LOW PRESSURE APPROACHES FROM THE
SW SUNDAY AND MOVES ACROSS THE REGION MONDAY. PRELIMINARY
INDICATIONS DO NOT INDICATE THAT A SCA WILL BE NEEDED WITH THIS
SYSTEM.
&&
.TIDES/COASTAL FLOODING...
WATER LEVELS AT BISHOPS HEAD AND CAMBRIDGE ARE EXPECTED TO
APPROACH MINOR FLOODING LATE TODAY AND EARLY THIS EVENING.
&&
.CLIMATE...
RECORD HIGHS FOR CHRISTMAS EVE/WED 12/24:
RICHMOND.......71 F (1988)
NORFOLK........75 F (1891)
SALISBURY......67 F (1990)
ELIZ CITY NC...75 F (1990)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ630>638-
650-652-654-656-658.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THURSDAY FOR ANZ633-634-
654-656-658.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 4 PM EST
THURSDAY FOR ANZ630>632.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 1 PM EST
THURSDAY FOR ANZ638.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THURSDAY FOR ANZ650-652.
&&
$$
SYNOPSIS...AJZ/ALB
NEAR TERM...AJZ
SHORT TERM...AJZ/LKB
LONG TERM...ESS
AVIATION...LSA
MARINE...LSA
TIDES/COASTAL FLOODING...
CLIMATE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
701 AM EST WED DEC 24 2014
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTHWARD THROUGH THE AREA THROUGH THIS
MORNING AS A LOW PRESSURE SYSTEM STRENGTHENS WEST OF THE MOUNTAINS.
AN ASSOCIATED COLD FRONT WILL CROSS THE AREA TONIGHT. HIGH PRESSURE
BUILDS BACK IN FROM THE SOUTHWEST CHRISTMAS DAY THROUGH FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
A DYNAMIC SYSTEM CONTINUES TO DEVELOP OVER THE CENTRAL GULF COAST
STATES AND TENNESSEE VALLEY EARLY THIS MORNING. LOCALLY...A RESIDUAL
COOL-WEDGE AIRMASS LINGERS WITH TEMPERATURES IN THE MID/UPPER 40S
W OF THE BAY. A WARM FRONT/COASTAL FRONT IS MOVING ONSHORE WITH
TEMPERATURES RISING INTO THE LOW/MID 60S OVER COASTAL SE VA AND NE
NC. THE FIRST BATCH OF RA HAS LIFTED NE OF THE LOCAL AREA. VSBYS
HAVE FALLEN IN THE WAKE OF THAT BATCH OF RA. THE LOWEST VSBYS ARE
ON THE COOL SIDE OF THE BOUNDARY FROM SOUTH CENTRAL VA ACROSS THE
HAMPTON ROADS AND INTERIOR NE NC. AN SPS HAS BEEN ISSUED TO
ACCOUNT FOR THIS. VSBY SHOULD RISE AS THE NEXT BATCH OF RAIN
ARRIVES FROM THE SW. DENSE FOG IS LIKELY TO DEVELOP OVER THE
WATER OVER THE NEXT FEW HOURS AS A WARM/MOIST AIRMASS OFF THE GULF
STREAM OVERSPREADS COOLER WATER.
THE NEXT BATCH OF RA WILL OVERSPREAD THE REGION THROUGH THE MORNING.
THE WARM FRONT SHOULD STEADILY LIFT SE-NW ACROSS THE COASTAL PLAIN
AND INTO THE I-95 CORRIDOR THIS MORNING AS THE LOW DEEPENS TO THE
W AND TRACKS NNE INTO THE OHIO VALLEY. A BLEND OF THE HI-RES ARW
AND HRRR RESULTS IN TEMPERATURES RISING INTO THE MID 60S TO NEAR
70 BY MIDDAY ROUGHLY ALONG AND E OF AN AVC-RIC-CGE LINE...WITH THE
WEDGE AIRMASS HOLDING STRONG OVER THE NW PIEDMONT.
PERIODS OF RA SHOULD CONTINUE THROUGH THE AFTERNOON. AS TEMPERATURES
AND DEWPOINTS RISE THERE IS A CHC OF THUNDER BY AFTERNOON WHEN
COMBINED WITH A STRONG SYSTEM TO THE W. CLOUDS/RA SHOULD LIMIT
DESTABILIZATION...SO SPC HAS ONLY THE SE PORTION OF THE AREA IN A
MARGINAL SEVERE RISK DESPITE A WARM MOISTURE RICH AIRMASS AND A
STRONG 925-700MB WIND FIELD. BY LATE AFTERNOON HIGHS SHOULD RANGE
FROM THE MID/UPPER 60S FOR CENTRAL PORTIONS TO AROUND 70 SE...WITH
MID/UPPER 50S OVER THE FAR NW PIEDMONT. HIGHS WILL BE NEAR
RECORDS...SEE THE CLIMATE SECTION BELOW FOR DETAILS.
THE COLD FRONT ARRIVES FROM THE W THIS EVENING AND MOVES W-E ACROSS
THE AREA AFTER MIDNIGHT. HIGH POPS CONTINUE THROUGH THE
EVENING...AND THEN RAPIDLY DIMINISH AFTER MIDNIGHT. A MENTION OF
THUNDER WILL BE MAINTAINED FOR THE AREA THROUGH THE EVENING...AND
THROUGH THE EARLY OVERNIGHT HOURS FOR COASTAL PORTIONS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
DRIER AIR ARRIVES CHRISTMAS MORNING AS HIGH PRESSURE BUILDS IN FROM
THE W. A SLOWER FRONTAL PASSAGE WILL RESULT IN A MILD CHRISTMAS
MORNING WITH LOWS RANGING FROM THE MID 40S FAR W...TO THE MID/UPPER
50S SE. THE SKY SHOULD BECOME MAINLY SUNNY WITH SCT AFTERNOON CU
ALONG WITH BREEZY WESTERLY FLOW BY MID/LATE MORNING CHRISTMAS DAY.
HIGHS SHOULD RANGE FROM THE MID 50S TO LOWER 60S CHRISTMAS DAY AS
CAA IS WEAK AND WILL BE OFFSET BY DOWNSLOPE WARMING (AND DUE TO A
WARM BEGINNING).
CLEAR/SEASONABLE THURSDAY NIGHT WITH LOWS IN THE UPPER 20S TO MID
30S. SURFACE HIGH PRESSURE SETTLES IMMEDIATELY OFF THE COAST FRIDAY
RESULTING IN LIMITED MIXING/LIGHT WINDS AND SUNNY CONDITIONS. HIGHS
SHOULD GENERALLY BE IN THE 50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE MODELS ARE IN GOOD AGREEMENT TO BEGIN THE PERIOD FRIDAY NIGHT
WITH THE STRONG RIDGING OVER THE SOUTHEASTERN US AND HIGH PRESSURE
OVER THE SOUTHEAST...CENTERED OVER EASTERN VA/NC. BUT THE MODELS
STRUGGLE WITH THE BREAKING DOWN OF THE RIDGE WITH THE GFS BREAKING
IT DOWN MUCH MORE QUICKLY THAN THE ECMWF. THE GFS ALLOW THE NEXT
COLD FRONT TO DROP INTO THE ARE SAT NIGHT AND MOVES IT SOUTH OF
THE REGION BY SUNDAY MORNING...SETTING UP AN OVERRUNNING PATTERN
SUNDAY AFTERNOON INTO MONDAY MORNING. THE ECMWF...AND THE 12Z IS
FURTHER NORTH WITH FEATURES THAN 00Z RUN...KEEPS THE RIDGE MUCH
STRONGER OVER THE SE AND DOES NOT ALLOW THE COLD FRONT TO MOVE
THROUGH THE AREA SAT NIGHT. IT STALLS THE FRONT OVER THE AREA ON
SUNDAY AND AS A WAVE OF LOW PRESSURE FORMS ALONG THE BOUNDARY AND
LIFTS NE INTO THE CENTRAL APPALACHIANS...IT PUSHES GULF MOISTURE
INTO THE AREA. THE 00Z ECMWF PUSHED THE WAVE OFF THE COAST BY
MONDAY...BUT THE 12Z RUN LIFTS THE LOW TO THE NORTH AND DRAGS A
COLD FRONT ACROSS THE REGION ON TUESDAY.
SO FOR NOW WITH THE GREAT SPREAD IN THE MODELS...HAVE TRENDED
TOWARD HPC/WPC GUIDANCE...WHICH IS SIMILAR TO THE 00Z ECMWF AND
BROUGHT THE WAVE INTO THE REGION ON SUNDAY AFTERNOON AND EVENING
WITH IT EXITING BY MONDAY AFTERNOON. HAVE INCREASED POPS TO 50%
FOR THAT PERIOD...KEEPING SATURDAY DRY. HAVE ALSO GONE DRY ON
MONDAY NIGHT INTO TUESDAY. THE BIG DIFFERENCE COMES TO
TEMPERATURES AS THE GFS WOULD ALLOW MUCH COLD AIR INTO THE REGION
BEGINNING ON SUNDAY THROUGH TUESDAY. THIS COULD ALSO POTENTIALLY
LEAD TO SOME WINTRY PCPN WITH WAVE ON SUNDAY NIGHT. FOR NOW HAVE
KEPT TEMPERATURES ABOVE FREEZING AND ALL RAIN WITH THE COLD AIR
BEING KEPT MORE TO THE NORTH. FOR TEMPERATURES HAVE ALLOW FOR A
GRADUAL COOL DOWN THROUGH THE PERIOD WITH THE COLDEST AIR ARRIVING
ON TUESDAY WITH HIGHS IN THE 40S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
LIFR CIGS WERE MOST PROMINENT ACRS THE CWA HOWEVER SOME TEMPORARY
IMPROVEMENT HAS DEVELOPED...ESPECIALLY IN THE VSBY AND MOST OFTEN IN
SE PORTIONS. THE WARM FRONT IS STILL JUST E OF HATTERAS DESPITE SE
WINDS AND INCREASING TEMPERATURES TOWARD COASTAL AREAS OF OUR CWA.
WITH THAT IN MIND...ANY IMPROVEMENT IN CIGS ARE EXPECTED TO BE
TEMPORARY. AN AREA OF RAIN...BRIEFLY HEAVY...WAS MOVING QUICKLY NE
THROUGH THE AREA. EXPECT THAT ONCE THE HEAVIER PCPN MOVES OUT THAT
CONDITIONS WILL BE MORE CONSISTENTLY IFR.
THE WARM FRONT IS EXPECTED TO LIFT TO THE NW/N WEDNESDAY MORNING.
DESPITE THE FACT THAT LAVMOS AND NAM MOS HAVE PERSISTENT IFR AT THE
TAF SITES...GFS MOS AND NAM DMO (DIRECT MODEL OUTPUT MOS) HAVE SOME
MODEST IMPROVEMENT BY EARLY AFTN AT ORF AND ECG AND POSSIBLY PHF.
WITH WARM SECTORING EXPECTED ESPECIALLY AT THESE LOCATIONS...HAVE
MVFR BY AROUND 18Z AT ORF AND ECG. HAVE TRIED TO APPLY IMPROVEMENT
CONSERVATIVELY. MODELS TEND TO IMPROVE WIDESPREAD IFR CONDS TOO FAST
BUT AT THE SAME TIME CAN BE TOO LOW IN WARM SECTOR SITUATIONS.
THEREFORE...CONFIDENCE IN THIS PART OF THE FORECAST IS LOW.
OUTLOOK...CURRENT FORECAST HAS WIDESPREAD PCPN WITH SLGT CHC FOR
THUNDER WEDNESDAY NIGHT AND EARLY THURSDAY MORNING. THE COLD FRONT
MOVES THROUGH THURSDAY MORNING SHIFTING WINDS TO WESTERLY.
CONDITIONS SHOULD IMPROVE RATHER QUICKLY FOLLOWING THE FRONTAL
PASSAGE. HIGH PRESSURE DOMINATES THROUGH SATURDAY WITH DRY WEATHER.
A CHC FOR RAIN RETURNS SUNDAY AS LOW PRESSURE APPROACHES FROM THE
WEST.
&&
.MARINE...
WILL CONTINUE TO MONITOR THE NEED FOR A DENSE FOG ADVISORY THIS
MORNING OVER THE MARINE AREA AS WARM MOIST AIR MOVES IN OVER
RELATIVELY COOL WATER.
AS OF 08Z...WINDS REMAIN LIGHT OVER THE MARINE AREA BUT ARE
FORECAST TO INCREASE FROM THE SE AND THEN S THIS MORNING AS A WARM
FRONT MOVES N THROUGH THE WATERS AND LOW PRESSURE DEEPENS OVER THE
OHIO VALLEY. SCA IS IN EFFECT FOR ALL THE WATERS EXCEPT THE RIVERS
SAVE THE LOWER JAMES. SCA CONDITIONS OVER INLAND WATERS MAY BE
MINIMAL AT FIRST DUE TO LIMITED MIXING BUT WILL BECOME MORE
FAVORABLE THURSDAY MORNING. HAVE ADDED THE LOWER JAMES WITH TIMES
STAGGERED SLIGHTLY FROM THE BAY (STARTING AT 21Z TODAY AND ENDING
3 HOURS EARLIER THURSDAY). LATER SHIFTS MAY NEED TO CONSIDER SCA
BEHIND THE COLD FRONT FOR OTHER RIVER ZONES ON THURSDAY MORNING.
SCA IS ALREADY IN EFFECT N OF PARRAMORE ISLAND. SEAS ARE EXPECTED TO
BUILD TO 5 FT OR HIGHER BY 18Z S OF THERE AND DECIDED TO BEGIN SCA S
OF PARRAMORE ISLAND AT 15Z TO ALLOW SUFFICIENT CUSHION.
HIGH PRESSURE THEN BUILDS INTO THE REGION ON THURSDAY NIGHT AND
LINGERS THROUGH SATURDAY AS A STRONG UPPER LEVEL RIDGE BUILDS INTO
THE SOUTHEASTERN US AND KEEPS STRONG HIGH PRESSURE AT THE SURFACE
OVER THE REGION THROUGH SATURDAY. LOW PRESSURE APPROACHES FROM THE
SW SUNDAY AND MOVES ACROSS THE REGION MONDAY. PRELIMINARY
INDICATIONS DO NOT INDICATE THAT A SCA WILL BE NEEDED WITH THIS
SYSTEM.
&&
.TIDES/COASTAL FLOODING...
WATER LEVELS AT BISHOPS HEAD AND CAMBRIDGE ARE EXPECTED TO
APPROACH MINOR FLOODING LATE TODAY AND EARLY THIS EVENING.
&&
.CLIMATE...
RECORD HIGHS FOR CHRISTMAS EVE/WED 12/24:
RICHMOND.......71 F (1988)
NORFOLK........75 F (1891)
SALISBURY......67 F (1990)
ELIZ CITY NC...75 F (1990)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ630>638-
650-652-654-656-658.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 4 PM EST
THURSDAY FOR ANZ630>634.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 1 PM EST
THURSDAY FOR ANZ638.
SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 4 PM EST
THURSDAY FOR ANZ654-656-658.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THURSDAY FOR ANZ650-652.
&&
$$
SYNOPSIS...AJZ/ALB
NEAR TERM...AJZ
SHORT TERM...AJZ/LKB
LONG TERM...ESS
AVIATION...LSA
MARINE...LSA
TIDES/COASTAL FLOODING...
CLIMATE...
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1050 AM EST WED DEC 24 2014
.SYNOPSIS...A WARM FRONT WILL LIFT NORTHWARD THROUGH THE CAROLINAS
TODAY AS A DEEPENING LOW PRESSURE SYSTEM TRACKS INTO THE TENNESSEE
VALLEY. A COLD FRONT WILL SURGE EAST ACROSS THE REGION TONIGHT AS
THE SURFACE LOW PROGRESSES NORTHWARD THROUGH THE OHIO VALLEY INTO
THE GREAT LAKES.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 1050 AM WEDNESDAY...
LARGE WARM CONVEYOR BELT PRECIP SHIELD STRETCHES FROM THE MID-
ATLANTIC COAST TO THE GULF OF MEXICO...WITH AN EMBEDDED QLCS FROM
SOUTH CAROLINA THROUGH THE FLORIDA PANHANDLE. MEANWHILE...THE WEDGE
AND COASTAL FRONTS CONTINUE THEIR RETREAT THROUGH THE COASTAL PLAIN
AND INTO THE PIEDMONT THIS MORNING...LEADING TO A STRONG BAROCLINIC
ZONE JUST EAST OF THE US-1 CORRIDOR. TEMPS ARE STILL IN THE MID 40S
NORTHWEST TO NOW UPPER 60S SOUTHEAST. THE BULK OF THE PRECIP WILL
CONTINUE TO SHIFT EAST THROUGH EARLY AFTERNOON IN CONCERT WITH THE
LOW-LEVEL JET....WITH SOME ENHANCEMENT ALONG THE AFOREMENTIONED
FRONTAL ZONE. A LULL IN PRECIP IS ANTICIPATED THIS AFTERNOON ON THE
HEELS OF THE LOW-LEVEL JET...WITH FORCING SOMEWHAT LIMITED GIVEN
THAT THE POSITIVELY TILTED UPPER TROUGH OVER THE MISSISSIPPI RIVER
VALLEY DOESNT MAKE ITS STRONG EASTWARD PUSH UNTIL TONIGHT. MOST OF
THE CAM`S SUPPORT THIS IDEA...WITH JUST ISOLATED TO WIDELY SCATTERED
SHOWERS AFTER 18Z. THE THREAT OF AN SEVERE WEATHER SHOULD REMAIN
CONFINED TO THE COASTAL PLAIN...WHERE MARGINAL CAPE AND STRONG
SHEAR PHASE THIS AFTERNOON. MODIFIED RAP SOUNDINGS SUGGEST 200-300
J/KG MLCAPE EAST OF I-95 IN THE TRUER WARM SECTOR... WITH 50-60KT
BULK SHEAR. HOWEVER...LOW-LEVEL HODOGRAPHS WILL BECOME MORE LINEAR
WITH TIME AS THE SURFACE WINDS CONTINUE TO VEER TO MORE
SOUTHWESTERLY....SO UNLESS THERE IS LOCAL BACKING IN RESPONSE TO
SOME PERTURBATION WITHIN THE FLOW...IT APPEARS THE CONDITIONAL
TORNADO THREAT WILL BE LIMITED TO THE SOUTHERN COASTAL PLAIN THROUGH
EARLY AFTERNOON.
CHANGES TO THE FORECAST ARE MOSTLY COSMETIC BASED ON TRENDS ON RADAR
AND OBS....WITH THE MAIN ADJUSTMENT TO THE NEAR TERM TEMPS AS
WARMING FROM THE TRIANGLE WESTWARD HAS BEEN A LITTLE SLOWER THAN
FORECAST. LATEST HRRR...WHICH HAS DONE A PRETTY GOOD JOB SO
FAR...SUGGESTS THE WEDGE MAY NOT BREAK IN THE FAR NORTHWEST PIEDMONT
UNTIL THE COLD FRONT ERODES THE AIRMASS LATER TONIGHT. HIGHS
ULTIMATELY END UP RANGING FROM 54-71 NORTHWEST TO SOUTHEAST. -BLS
PRECIP TONIGHT: PRECIPITATION MAY RE-DEVELOP IN THE FORM OF A NARROW
CONVECTIVE LINE LATER THIS EVENING (ROUGHLY 00-06Z) AS THE SFC COLD
FRONT SURGES EASTWARD THROUGH CENTRAL NC. CONFIDENCE IS LOWER THAN
NORMAL WITH REGARD TO THE EVOLUTION OF PRECIPITATION ALONG THE COLD
FRONT THIS EVENING...PARTICULARLY WITH REGARD TO PRE-FRONTAL THERMAL
PROFILES /INSTABILITY/ DUE TO THE WIDE VARIETY OF MECHANISMS AND
POSSIBLE INTERACTIONS DRIVING THE EVOLUTION THEREOF. BASED ON
PREVIOUS EXPERIENCE WITH SIMILAR SETUPS AND THE LATEST MODEL
GUIDANCE...EXPECT THE BEST POTENTIAL FOR ADDITIONAL PRECIPITATION
ALONG AND EAST OF HWY 1 IN THE 01-07Z TIME FRAME. FOR EXAMPLE...THE
HIGH-RES WRF-ARW SUGGESTS DRY CONDITIONS IN THE WESTERN PIEDMONT
WITH A NARROW LINE OF CONVECTION DEVELOPING IN VICINITY OF THE
TRIANGLE AROUND MIDNIGHT...EXITING THE COASTAL PLAIN BY 2-3 AM THU
MORNING.
WHETHER OR NOT CONVECTION WILL ACCOMPANY THE COLD FRONTAL PASSAGE
LATE THIS EVENING INTO TONIGHT ALSO REMAINS UNCLEAR. THE 00Z WRF-ARW
SUGGESTS THAT CONVECTION WILL DEVELOP ALONG THE FRONT AS IT
PROGRESSES FROM THE TRIANGLE INTO THE COASTAL PLAIN BETWEEN 01-07Z.
AN ISOLD SEVERE STORM CAPABLE OF PRODUCING DAMAGING WINDS CANNOT BE
RULED OUT IN THAT TIME FRAME...SHOULD CONVECTION DEVELOP. -VINCENT
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 255 AM WEDNESDAY...
THERE MAY BE A FEW SHOWERS IN THE PROCESS OF EXITING THE FAR EASTERN
ZONES CHRISTMAS MORNING... OTHERWISE EXPECT A WEST TO EAST CLEARING
TRENDING IN THE WAKE OF THE EXITING COLD FRONT.
ADDITIONALLY...DEEPENING SURFACE LOW LIFTING NEWD INTO SE CANADA
WILL RESULT IN BREEZY CONDITIONS ON CHRISTMAS DAY...WITH WEST-
NORTHWESTERLY WINDS GUSTING INTO THE UPPER TEENS TO LOWER
20S...STRONGEST DURING THE FIRST HALF OF THE DAY. WEAK CAA BEHIND
THE FRONT WILL STILL ALLOW FOR SEASONABLY MILD TEMPERATURES. HIGHS
IN THE MID 50S NW TO LOWER 60S SE. LOWS IN THE LOWER TO MID 30S.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 255 AM WEDNESDAY...
SATURDAY NIGHT INTO MONDAY...A PATTERN CHANGE WILL BEGIN TO OCCUR AS
THE UPPER RIDGE OVER THE SE STATES BREAKS DOWN AND A LARGE MID/UPPER
TROUGH DEVELOPS INTO THE WEST-CENTRAL THEN CENTRAL STATES. THE LEAD
COLD FRONT IS EXPECTED TO PUSH INTO NC FROM THE NORTH LATE SUNDAY OR
SUNDAY NIGHT. ALL BETS ARE OFF ON HOW FAR SOUTH THIS INITIAL FRONT
WILL BE ABLE TO SAG INTO NC OR SC. ABOUT HALF THE GFS ENSEMBLE
MEMBERS SUPPORT A STRONG ENOUGH SURFACE HIGH OVER A FAVORED GREAT
LAKES LOCATION TO PUSH THE FRONT INTO SC. THIS IS NOT SUPPORTED BY
THE LATEST OPERATIONAL EC AND HALF THE RELATED ENSEMBLES. THE
STRENGTH OF THE SURFACE WAVE SLATED TO DEVELOP OVER THE LOWER
MISSISSIPPI VALLEY AND THE SUBSEQUENT TRACK (EITHER JUST TO OUR WEST
AND NORTH... OR VERY NEAR OR OVER OUR REGION) IS ALSO CURRENTLY
DEBATABLE. WPC HAS SPLIT THE MIDDLE TAKING THE AVERAGE APPROACH
WHICH WOULD KEEP MOST OF OUR REGION IN THE WARM SECTOR INITIALLY
(UNTIL THE INITIAL WAVE OF LOW PRESSURE PASSES). THIS WOULD ENSURE
ALL RAIN AND MILDER TEMPERATURES THAN IF CAD WERE TO DEVELOP PER
SOME OF THE GFS MEMBERS. FOR NOW... WE WILL TREND A BIT COOLER AND
WETTER... AND TOWARD THE COOLER SOLUTIONS AND GIVE IT A FEW MORE
RUNS BEFORE COMMITTING EITHER WAY. THIS WOULD LEAD TO A CHANCE OF
RAIN LATE SUNDAY INTO MONDAY WITH LOWS IN THE MID 30S TO MID 40S AND
HIGHS IN THE MID 40S TO LOWER 60S N TO SE.
A TURN TO SHARPLY COLDER WEATHER IS EXPECTED BY MID NEXT WEEK WITH
LOWS BACK INTO THE 20S AND HIGHS IN THE 40S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 730 AM WEDNESDAY...
24-HR TAF PERIOD: LIFR CONDITIONS ASSOCIATED WITH A PRONOUNCED COLD
AIR DAMMING WEDGE WILL PERSIST OVER CENTRAL NORTH CAROLINA THIS
MORNING AS WIDESPREAD PRECIPITATION OVERSPREADS THE REGION FROM THE
SOUTH/SW. GRADUAL IMPROVEMENT TO IFR AND PERHAPS LOW-END MVFR IS
EXPECTED FROM SOUTH/SE TO NORTH/NW LATE THIS MORNING INTO THIS
AFTERNOON AS A WARM FRONT LIFTS NORTHWARD THROUGH CENTRAL NC...
EARLIEST AT THE FAY TERMINAL AND LATEST AT THE INT/GSO TERMINALS.
SOUTHERLY LOW LEVEL WIND SHEAR WILL LOWER IN ALTITUDE (FROM ~1500 FT
AGL TO 500 FT AGL) THROUGH NOON AS A LOW PRESSURE SYSTEM DEEPENS
WEST OF THE MOUNTAINS AND THE COLD AIR DAMMING WEDGE GRADUALLY
SHALLOWS/ERODES. LOW LEVEL WIND SHEAR WILL END BY EARLY AFTERNOON AS
THE CAD WEDGE DISSIPATES AND VERTICAL MIXING INCREASES. IFR OR LOW-
END MVFR CONDITIONS...A CHANCE FOR SHOWERS/STORMS...AND A SOUTHERLY
BREEZE WILL PREVAIL THIS AFTERNOON AND EVENING...IN ADVANCE OF A
COLD FRONT APPROACHING FROM THE WEST. VFR CONDITIONS WILL RETURN
FROM WEST-EAST BETWEEN MIDNIGHT AND SUNRISE THURSDAY AS BREEZY
WEST/NW WINDS ADVECT A DRIER AIRMASS INTO THE REGION IN THE WAKE OF
THE COLD FRONT.
LOOKING AHEAD: VFR CONDITIONS WILL PREVAIL THURSDAY INTO THE WEEKEND
IN ASSOCIATION WITH HIGH PRESSURE OVER THE REGION. -VINCENT
&&
.HYDROLOGIC DISCUSSION /THROUGH THURSDAY/...
AS OF 210 PM TUESDAY...
THERE HAVE BEEN THREE FAIRLY SIGNIFICANT RAINFALL EVENTS OVER
CENTRAL NORTH CAROLINA DURING THE PAST TWO WEEKS...WITH HEAVIER
RAINFALL AMOUNTS (>1 INCH TOTAL) GENERALLY FROM THE TRIANGLE AND
FAYETTEVILLE AREAS EAST TO THE COAST. AS A RESULT...RELATIVE SOIL
MOISTURE IS UNIFORMLY HIGH THROUGH A 200 CM DEEP COLUMN...WHICH WILL
PROMOTE FASTER RUNOFF AS WELL AS A HIGHER PERCENTAGE OF RAINFALL-TO-
RUNOFF FROM THE UPCOMING EVENT TONIGHT THROUGH CHRISTMAS MORNING.
CURRENT QUANTITATIVE PRECIPITATION FORECASTS RANGE FROM 1.25 INCHES
TO NEARLY 2 INCHES...AND HAVE BEEN TRENDING DOWNWARD WITH SUCCESSIVE
MODEL RUNS. AT THIS TIME...OUR PREFERRED RAINFALL FORECAST IS FOR
WIDESPREAD AMOUNTS OF LESS THAN 1.5 INCHES...WHICH WILL CAUSE
MAINSTEM RIVERS TO RISE SEVERAL FEET FROM CHRISTMAS DAY INTO THE
WEEKEND...BUT RIVER FORECAST POINTS WOULD CREST BELOW MINOR FLOOD
STAGE. WIDESPREAD RAIN NEARER THE HIGH END OF THIS RANGE (1.75 TO
2 INCHES) WOULD LIKELY PRODUCE MINOR FLOODING ON EASTERN RIVERS...
PARTICULARLY THE HAW...NEUSE...AND TAR RIVERS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT/BLS
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...VINCENT
HYDROLOGY...BADGETT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1042 AM EST WED DEC 24 2014
.SYNOPSIS...
LOW PRESSURE TO THE WEST OF THE APPALACHIANS WILL DEEPEN AND LIFT
NORTH TOWARD THE GREAT LAKES TODAY. THIS LOW WILL DRAG A COLD FRONT
THROUGH THE COASTAL CAROLINAS TONIGHT. DRY HIGH PRESSURE
WILL BUILD OVER THE SOUTHEAST CHRISTMAS DAY INTO FRIDAY BEFORE
MOVING OFF THE COAST SATURDAY. A COLD FRONT WILL DROP INTO THE
SOUTHEAST ON SUNDAY WITH A FEW WAVES OF LOW PRESSURE DEVELOPING
MONDAY THROUGH WEDNESDAY NEXT WEEK...LEAVING UNSETTLED WEATHER
ACROSS THE CAROLINAS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM WEDNESDAY...COMPLEX AND ACTIVE WEATHER ON TAP FOR MUCH
OF THE SOUTHEAST ON THIS CHRISTMAS EVE.
FULL LATITUDE UPPER TROUGH ALIGNED FROM THE WESTERN GREAT LAKES DOWN
INTO EASTERN TEXAS IS SLOWLY DRIFTING EAST THIS MORNING. BENEATH
THIS TROUGH...A STRENGTHENING SURFACE LOW IS MOVING NORTH INTO THE
GREAT LAKES...AND ALTHOUGH THIS WILL STAY WELL AWAY FROM THE
CWA...IT WILL DRIVE A STRONG COLD FRONT ACROSS THE REGION TONIGHT.
THE COMBINATION OF WAA AHEAD OF THE COLD FRONT...INCREASING THETA-E
RIDGING...AND DIFFLUENCE WITHIN AN UPPER JET WILL CREATE WIDESPREAD
SHOWERS WITH ISOLATED TSTMS TODAY. WHILE PRECIP WILL BE WIDESPREAD
AND HEAVY AT TIMES...TWO BIG QUESTION MARKS STILL REMAIN...AND THESE
ARE WHETHER SEVERE THUNDERSTORMS WILL DEVELOP...AND AT WHAT TIME THE
PRECIP WILL END TODAY.
KLTX IMAGERY THIS MORNING SHOWS AN AREA OF HEAVIER RAINFALL MOVING
ACROSS THE ILM NC COUNTIES...WITH SCATTERED BUT LESS INTENSE SHOWER
ACTIVITY TO THE SOUTHWEST. REGIONAL MOSAIC HAS A LINE OF CONVECTION
FROM WEST OF COLUMBIA, SC...TO VALDOSTA, GA. HIGH RES HRRR AND WRF
SUGGEST A LULL IN PRECIP FOR SEVERAL HOURS THIS AFTN AHEAD OF THE
FORCED LINE...AND HAVE TRIED TO SHOW POP TRENDS MIMICKING THIS IDEA.
THIS SEEMS PLAUSIBLE SINCE DIFFLUENCE THIS MORNING WILL WEAKEN AND
SOME SUBSIDENCE IS LIKELY IN THE WAKE OF THIS MORNINGS ACTION.
HOWEVER...ISOLATED THUNDER WILL STILL BE POSSIBLE THROUGH NOON OR
SO...ESPECIALLY IN PLACES WHERE TEMPS HIT 70-72F SINCE THAT WILL BE
CAPABLE OF TAPPING THE INSTABILITY ABOVE 950MB PRESENT ON THE 12Z
KCHS UA SOUNDING. HEAVY RAIN WILL BE THE PRIMARY THREAT THIS
MORNING...AND SOME PLACES MAY PICK UP A QUICK 1 INCH OF QPF IN
EMBEDDED TSTMS.
THEREAFTER...ATTN TURNS TO THE PRE-FRONTAL FORCED LINE AND ITS
ANTICIPATED IMPACTS LOCALLY. AS THE LOW PRESSURE MOVES NORTH...THE
EASTWARD PROGRESS OF THIS LINE WILL SLOW...AND THEREFORE BELIEVE THE
WRF IS TOO FAST IN ITS EVOLUTION...BUT STILL ACCURATE IN ITS OVERALL
DEPICTION. SPC SWODY1 HAS THE AREA IN A MARGINAL RISK...WITH A
SLIGHT RISK SOUTH OF MYRTLE BEACH...FOR POSSIBLE DAMAGING WINDS AND
ISOLATED TORNADOES AS THIS QLCS APPROACHES. LOCALLY THE TORNADO
THREAT SEEMS EXTREMELY LOW WITH MLCAPES OF 300 J/KG OR LESS AND
0-3KM SRH REACHING ONLY AS HIGH AS AROUND 200 M2/S2. AT THE SAME
TIME...LOW-LEVEL WINDS OF 50 KTS AT 2KFT WILL SLOWLY VEER MORE TO
THE SW THIS AFTN...ERODING EVEN FURTHER THE TORNADO THREAT...BUT
MAINTAINING A DAMAGING WIND POTENTIAL. WILL HAVE TO MONITOR
EVOLUTION OF THIS SQUALL LINE AS IT REACHES THE CWA...AND IT WILL
LIKELY DO SO IN A WEAKENING STATE...BUT CANNOT RULE OUT AN ISOLATED
DAMAGING WIND GUST THIS EVENING. A LARGE AREA OF TRAILING STRATIFORM
RAIN WILL PERSIST BEHIND THE SQUALL LINE...AND THUS EVEN THOUGH THE
COLD FRONT DOES NOT CROSS THE CWA UNTIL AFTER MIDNIGHT...IT WILL
HAVE DIFFICULTY DEVELOPING ANY CONVECTION OTHER THAN SHALLOW SHOWERY
TYPE PRECIP.
HIGHS TODAY WILL RISE INTO THE LOW 70S MOST AREAS EVEN WITHOUT ANY
SUNSHINE THANKS TO STRONG WAA. TEMPERATURES WILL BEGIN TO CRASH
BEHIND THE COLD FRONT AFTER MIDNIGHT...BUT ONLY A FEW HOURS OF
COOLING BEFORE DAYBREAK WILL LIMIT MINS TO AROUND 50 WELL
INLAND...AND NEAR 60 RIGHT ALONG THE COAST.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...A COLD FRONT WILL BE PUSHING FARTHER OFF
SHORE THROUGH THURS AS HIGH PRESSURE BUILDS UP FROM GULF COAST.
ANY LINGERING PCP OR MOISTURE WILL BE SCOURED OUT AS MID TO UPPER
TROUGH MOVES EAST LEAVING A DEEP DRY AND COOLER W-NW FLOW BEHIND
IT. EXPECT PCP WATER VALUES DOWN FROM UP NEAR 2 INCHES THE NIGHT
BEFORE TO A QUARTER OF INCH BY THURS AFTERNOON AS COLUMN DRIES
OUT. OVERALL EXPECT CLEARING SKIES ON CHRISTMAS DAY WITH SUNSHINE
MAKING AN APPEARANCE FOR THE FIRST TIME IN SEVERAL DAYS. TEMPS
SHOULD NOT MOVE MUCH ON THURS AS A WARM START TO THE DAY WILL BE
FOLLOWED BY GUSTY W-NW WINDS BRINGING IN RELATIVELY COOLER AIR.
MODELS HAVE BEEN CONSISTENTLY BACKING OFF ON CAA BEHIND THE FRONT
WITH 850 TEMPS ONLY FALLING ABOUT 6 C BEHIND FRONT BEFORE LEVELING
OFF AND RISING SLIGHTLY THROUGH FRI. TEMPS THURS NIGHT SHOULD BE
DOWN IN THE 30S AND BASICALLY EXPECT SEASONABLE TO ABOVE NORMAL
TEMPS IN THE FORECAST AS HIGH PRESSURE BUILDS UP FROM THE GULF
COAST OVER THE SOUTHEAST THROUGH FRI.
THE CENTER OF THE HIGH ALMOST DIRECTLY OVERHEAD FRI AFTN WILL
SHIFT OFF SHORE BY FRI NIGHT LEAVING A LIGHT RETURN FLOW. THIS
WILL HELP TO CAUSE A SLIGHT RISE IN DEWPOINT TEMPS AND THEREFORE
WILL KEEP TEMP A BIT HIGHER THAN THE NIGHT BEFORE BUT THE WINDS
WILL BE LIGHT ENOUGH UNDER CLEAR SKIES TO PRODUCE DECENT
RADIATIONAL COOLING. THIS WILL BRING TEMPS DOWN CLOSER TO 40 FOR
FRI NIGHT.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 330 AM WEDNESDAY...RIDGE OF HIGH PRESSURE UP THE SOUTHEAST
COAST ON SATURDAY WILL SHIFT EAST THROUGH EARLY NEXT WEEK. THIS
WILL ALLOW A RETURN FLOW TO SET UP WITH SW-W WINDS THROUGH THE
LOW TO MID LEVELS OF THE ATMOSPHERE. INITIALLY SHOULD SEE A FAIR
AMOUNT OF SUNSHINE ON SATURDAY BUT A COLD FRONT WILL DROP SOUTH ON
SUNDAY LEAVING SHALLOW COOL AIR IN PLACE. SHOULD SEE CLOUDS AND
PCP SPREAD OVER THE CAROLINAS SAT NIGHT INTO SUNDAY AS COLD FRONT
DROPS SOUTH WITH SOME DECENT ISENTROPIC LIFT DEVELOPING. THE GFS
AND ECMWF SHOW A FEW WAVES OF LOW PRESSURE MOVING UP FROM THE
GULF COAST ALONG THIS FRONT THROUGH NEXT WEEK. MAY END UP WITH AN
EXTENDED PERIOD OF UNSETTLED WEATHER AS POSSIBLE WEDGE SETS UP.
TEMPS ON SAT INTO SUNDAY SHOULD REMAIN ON THE WARM SIDE WITH 60S
MOST PLACES. SOME UNCERTAINTY EXISTS WITH LOCATION OF COLD FRONT
AS ECMWF KEEPS IT NORTH AND SHOWS WAVES OF LOW PRESSURE MOVING
ALONG FRONT TO THE NORTH OF LOCAL AREA. THIS COULD KEEP LOCAL AREA
IN WARMER SW FLOW AT THE SURFACE WITH WEDGE HOLDING INLAND AND TO
OUR NORTH.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...MODERATE SHOWERS ARE TRAINING OVER THE WESTERN PORTION
OF THE REGION...WITH ANOTHER SLUG OF PRECIP MOVING UP THE COAST.
THIS BATCH WILL MOVE INTO THE MYRTLES IN ABOUT AN HOUR. THE HRRR
MODEL INITIALIZED FAIRLY WELL AND SHOWS THE PRECIP WEAKENING LATER
THIS MORNING. SOUTHERLY WINDS WILL INCREASE THIS MORNING...GUSTING
NEAR 20 KTS AT TIMES. ANOTHER BATCH OF PRECIP WILL EMERGE JUST AHEAD
OF THE COLD FRONT THIS AFTERNOON THROUGH THE EARLY EVENING HOURS.
REALLY DIFFICULT TO TIME EVERYTHING...SAFE TO SAY AVIATION
CONDITIONS TODAY WILL BE HIGHLY VARIABLE...WITH IFR CONDITIONS IN
THE HEAVIER PRECIP. COULD NOT RULE OUT THUNDER TODAY...BUT COVERAGE
WILL BE LIMITED AND EMBEDDED IN WIDESPREAD PRECIP. THERE WILL BE
WIND SHIFT LATE TONIGHT AS THE FRONT PUSHES TO THE COAST.
EXTENDED OUTLOOK...PRECIP ENDING NEAR THE COAST LATE TONIGHT WITH
THE COLD FRONT PUSHING TO THE COAST THURSDAY MORNING WITH GUSTY WEST
WINDS. VFR FRIDAY AND SATURDAY. RAIN RETURNING SUNDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM WEDNESDAY...TROPICAL AIRMASS BEHIND A WARM FRONT NOW
SITUATED WELL INLAND IS ADVECTING INTO THE WATERS THIS
MORNING...WITH DEWPOINT TEMPERATURES APPROACHING 70...OR EVEN THE
LOW 70S. THESE DEWPOINT TEMPS ARE 15 DEGREES ABOVE THE COOL SHELF
WATER TEMPS...WHICH IS TYPICALLY A SIGNAL FOR SEA FOG. ATTM
HOWEVER...NO VSBY RESTRICTIONS HAVE BEEN NOTED AND IT MAY BE SIMPLY
DUE TO THE STRENGTH OF THE WIND FIELDS NOT ALLOWING FOR AMPLE PARCEL
RESIDENCE TIME. STILL...THE MARINE DENSE FOG ADVISORY REMAINS AND
WILL CONTINUE AS THERE REDUCED VISIBILITY IN MARINE FOG IS STILL
EXPECTED TO DEVELOP UNTIL THE COLD FRONTAL PASSAGE TONIGHT.
SHOWER ACTIVITY WILL BE SCATTERED THROUGH THE AFTN AND EVE...BEFORE
A MORE STRONGLY FORCED SQUALL LINE WILL CROSS THE WATERS THIS
EVENING AND TONIGHT. WINDS WILL BE GUSTY TODAY EVEN OUTSIDE OF
CONVECTION...AND THE CURRENT SCA REMAINS UNCHANGED FOR BOTH WINDS
AND SEAS...WHICH ARE ALREADY APPROACHING 7 FT AT WILMINGTON HARBOR
BUOY. A WIND SHIFT TO THE WEST WILL OCCUR WITH THE FROPA...WHICH IS
EXPECTED AFTER MIDNIGHT.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...COLD FRONT WILL SHIFT FARTHER OFF SHORE ON
THURS AS HIGH PRESSURE BUILDS UP FROM THE GULF COAST. GUSTY W-SW
WINDS EARLY THURS WILL VEER AROUND BECOMING WEST THROUGH THE DAY.
SEAS UP AROUND 5 TO 7 FT SHOULD FALL BELOW SCA THRESHOLDS BY THURS
AFTN WITH HIGHEST SEAS GETTING PUSHED FARTHER OFF SHORE IN STRONGER
W-NW FLOW BEHIND FRONT. WINDS WILL VEER FURTHER TO THE NW AND
LIGHTEN UP LATE THURS INTO FRI AS CENTER OF HIGH SHIFTS CLOSER
OVERHEAD. SEAS WILL BE DOWN TO 2 TO 4 FT BY THURS NIGHT AND DOWN TO
3 FT OR LESS THROUGH FRI AS HIGH PRESSURE MOVES OVERHEAD WITH MORE
VARIABLE WINDS EXPECTED.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 330 AM WEDNESDAY...HIGH PRESSURE WILL SHIFT FARTHER OFF
SHORE ON SATURDAY WITH A RETURN FLOW S-SW 10 KTS OR LESS SETTING
UP. A COLD FRONT WILL DROP SOUTH SUN WITH POSSIBLE WEDGE
DEVELOPING WITH WINDS VEERING AROUND TO THE N-NE AS IT DROPS SOUTH
SUN NIGHT. THIS WILL PUSH SEAS UP A BIT BUT OVERALL BUT EXPECT
SEAS TO GENERALLY 3 FT OR LESS THROUGH THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 6 PM EST THIS EVENING FOR AMZ250-252-
254-256.
SMALL CRAFT ADVISORY UNTIL NOON EST THURSDAY FOR AMZ250-252-
254-256.
&&
$$
NEAR TERM...17
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...43
AREA FORECAST DISCUSSION
NWS BISMARCK ND
946 AM CST WED DEC 24 2014
.UPDATE...
ISSUED AT 945 AM CST WED DEC 24 2014
UPDATE HAS BEEN ISSUED. OBSERVATIONS SHOW FOG CONTINUES IN PARTS
OF CENTRAL NORTH DAKOTA...SO EXTENDED PATCHY FOG FOR THE REMAINDER
OF THE MORNING HOURS. EARLY MORNING RADAR MOSAIC SHOWS WEAK ECHOES
MOVING ACROSS PARTS OF WESTERN AND CENTRAL NORTH DAKOTA...BUT
LITTLE TO NO PRECIPITATION HAS BEEN REACHING THE GROUND. A DRY
LAYER IS APPARENT FROM THE 24.12Z BISMARCK SOUNDING WHICH HAS BEEN
INHIBITING THE PRECIPITATION. THINK THE CURRENT SMALL POPS COVER
THIS SCENARIO. DEBATED THE POTENTIAL FOR A BRIEF PERIOD OF VERY
LIGHT FREEZING RAIN / SPRINKLES IN THE SOUTHWEST WHERE WARMER AIR
ALOFT HAS ARRIVED. DECIDED TO ADD IT INTO THE FORECAST FOR JUST A
COUPLE HOURS UNTIL SURFACE TEMPERATURES RISE ABOVE FREEZING.
UPDATE ISSUED AT 637 AM CST WED DEC 24 2014
THE MAIN CHANGE WITH THIS UPDATE WAS TO ADJUST HOURLY FORECAST TEMPS
TO MATCH OBSERVED VALUES IN CENTRAL AND EASTERN LOCATIONS WHERE
TEMPS WERE RUNNING ABOVE FORECAST VALUES DUE TO CLOUD COVER. THE
SAME AREA HAS NUMEROUS REPORTS OF FOG...THOUGH NO SIGNIFICANT
REDUCTIONS IN VISIBILITY AT THIS TIME...GENERALLY 3-5SM VIS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 339 AM CST WED DEC 24 2014
THE MAIN CONCERN IN THE SHORT WILL BE FOG THIS MORNING...THEN
ATTENTION TURNS TO CHANCES OF PRECIPITATION...WITH AND WEATHER TYPE
DURING THE DAY.
CURRENTLY...A WEAK SURFACE RIDGE AXIS EXTENDED ACROSS EASTERN NORTH
DAKOTA - BETWEEN A STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES
AREA AND DEVELOPING LOW PRESSURE IN THE LEE OF THE ROCKIES. ALONG
AND EAST OF THIS RIDGE IS A LARGE STRATUS CLOUD FIELD EXTENDING FROM
THE EASTERN DAKOTAS TO THE GREAT LAKES. IN THE WESTERN DAKOTAS
CIRRUS CLOUDS COVERED MOST OF THE AREA...WITH PATCHY/OCCASIONAL FOG
REPORTED...SOMETIMES LIGHT FOG AND SOMETIMES VISIBILITIES DROP DOWN
TO 1/2 MILE OR LESS FOR SHORT PERIODS.
THE VARIOUS RUNS OF THE HRRR MODEL HAVE SUGGESTED THAT THE WESTERN
EDGE OF THE STRATUS DECK SHOULD ERODE WITH TIME...WITH PATCHY AREAS
OF DENSE FOG FORMING IN THE IMMEDIATE CLEARING OF THE STRATUS.
HOWEVER THE MODEL SUGGESTS THE DENSE FOG NOT LASTING/LINGERING IN
ANY ONE AREA. MEANWHILE INCREASING MID LEVEL CLOUDS MOVING IN FROM
EASTERN MONTANA SHOULD EVENTUALLY LIMIT ANY FOG FORMATION. THUS WILL
KEEP A MENTION OF PATCHY FOG OVER THE WESTERN HALF OF THE STATE
THROUGH AROUND 6 AM...THEN CONTINUE THE PATCHY FOG MENTION OVER ALL
OF CENTRAL NORTH DAKOTA UNTIL AROUND 9 AM.
THE NEXT WEATHER SYSTEM TO AFFECT NORTH DAKOTA IS OVER THE WESTERN
COAST OF NORTH AMERICA EARLY THIS MORNING. BROAD ZONAL FLOW WAS OVER
THE NORTHERN PLAINS AHEAD OF THE SYSTEM WITH LOW PRESSURE IN NORTH
CENTRAL CANADA. THE ZONAL FLOW CONTAINS SOME UPPER LEVEL IMPULSE
ENERGY THAT WAS ASSOCIATED WITH A MID-LEVEL DECK OF CLOUDS OVER
SASKATCHEWAN/MONTANA MOVING EASTWARD...WITH SOME LIGHT RADAR RETURNS
SEEN ON THE RADAR MOSAIC. SURFACE LOW PRESSURE IN THE LEE OF THE
ROCKIES THIS MORNING WILL MOVE EAST ACROSS THE DAKOTAS TODAY. WARM
ADVECTION AHEAD/ALONG THE SYSTEM WAS MOVING INTO WESTERN NORTH
DAKOTA THIS MORNING. THERE IS A SLIGHT CHANCE OF LIGHT PRECIPITATION
WITH THIS UPPER LEVEL ENERGY AS IT MOVES EAST ACROSS THE REGION. THE
MAIN QUESTION IS WHETHER FREEZING RAIN WILL BE AN ISSUE THIS
MORNING. THE APPROACH OF THE MID CLOUD DECK WILL MEAN THAT ICE
CRYSTALS WILL BE LIKELY AT MID AND UPPER LEVELS. SHOULD ANY OF THESE
ICE CRYSTALS FALL INTO LOWER LAYERS OF THE ATMOSPHERE...PROGGED
MODEL SOUNDINGS SUGGEST THAT INITIALLY THERE IS A WARM
LAYER/INVERSION - BUT THAT THE FROST POINT WITHIN THIS LAYER IS MUCH
COOLER THAN THE DRY BULB TEMPERATURE. THUS PARTICLES FALLING THROUGH
SHOULD COOL TOWARDS THE FROST POINT AND REMAIN COOL ENOUGH FOR ALL
SNOW. LATER IN THE DAY AS SURFACE TEMPERATURES WARM ABOVE FREEZING -
MAINLY IN THE WEST - PRECIPITATION WOULD CHANGE TO RAIN.
TONIGHT THE COLD FRONT PORTION OF THE WEATHER SYSTEM WILL MOVE
SOUTHEAST ACROSS THE STATE. AS THIS OCCURS...THE UPPER LEVEL FLOW
BECOMES MORE SOUTHWESTERLY ACROSS THE DAKOTAS - AND THE LEADING EDGE
OF A SERIES OF UPPER LEVEL ENERGY IMPULSES AND MID LEVEL MOISTURE
ARRIVES. BY THIS TIME ANY PRECIPITATION THAT FALLS SHOULD BE IN THE
FORM OF SNOW...OR AT LEAST CHANGING OVER FROM RAIN TO SNOW. MOST OF
THE SNOW SHOULD OCCUR OVER MONTANA AND NORTHERN WYOMING...WITH
SOUTHWESTERN NORTH DAKOTA AND NORTHWESTERN SOUTH DAKOTA RECEIVING
SOME LIGHT SNOW BY CHRISTMAS MORNING. ESTIMATES ARE THAT BY
CHRISTMAS MORNING SNOW AMOUNTS OF AROUND 1/2 INCH WOULD BE COMMON IN
THE SOUTHWEST...MAINLY FROM BEACH TO DICKINSON TO HETTINGER AND
POINTS SOUTH AND WEST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 339 AM CST WED DEC 24 2014
MAIN FORECAST CHALLENGES INVOLVE LIGHT SNOW ACROSS SOUTHERN NORTH
DAKOTA CHRISTMAS DAY AND MUCH COLDER WEATHER BY FRIDAY AND
CONTINUING INTO NEXT WEEK. LATEST 00Z DETERMINISTIC MODELS AS WELL
AS SREF ARE IN GOOD AGREEMENT WITH KEEPING MEASURABLE PRECIP IN THE
FORM OF SNOW ALONG AND SOUTH OF THE ND/SD BORDER ON CHRISTMAS DAY.
THIS INCLUDES THE 00Z NAM WHICH HAS COME BACK IN LINE WITH OTHER
MODEL GUIDANCE WITH A MORE SOUTHWARD LOCATION OF SNOW. MAY SEE
AROUND AN INCH OF SNOW ACCUMULATION CLOSE TO THE STATE BORDER.
WHILE THE SURFACE LOW RESPONSIBLE FOR THIS SNOW MOVES NORTHEAST FROM
THE CENTRAL PLAINS TO THE GREAT LAKES REGION THURSDAY/FRIDAY...
NORTHERLY WINDS WILL ADVECT ARCTIC AIR ACROSS THE NORTHERN PLAINS.
HIGH TEMPS WILL BE IN THE TEENS AND 20S FRIDAY THROUGH THE WEEKEND
BEFORE A STRONGER ARCTIC FRONT PUSHES ACROSS THE REGION EARLY
SUNDAY. SOME DIFFERENCES IN HEIGHT FIELDS DEVELOP BETWEEN
GFS/ECMWF EARLY NEXT WEEK ALTHOUGH BOTH ARE IN AGREEMENT WITH
EXTENSIVE LONG WAVE TROUGH APPROXIMATELY FROM HUDSON BAY TO
INTERMOUNTAIN WEST. GFS HAS -30C CORE AT 850MB OVER NORTHEAST ND
ON TUESDAY WITH THE ECMWF SLIGHTLY WARMER. REGARDLESS...VERY COLD
CONDITIONS EXPECTED WITH WIND CHILLS REACHING DANGEROUS LEVELS
UNDER NORTHWEST FLOW MONDAY NIGHT AND TUESDAY NIGHT WITH 1050MB
SURFACE HIGH SETTING UP OVER WESTERN MONTANA. MAJORITY OF THE CWA
CURRENTLY LOOKS TO REACH WIND CHILL ADVISORY CRITERIA FOR THESE
TIME PERIODS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 637 AM CST WED DEC 24 2014
WIDESPREAD MVFR/IFR WILL CONTINUE FROM KBIS-KMOT-KJMS THIS MORNING
IN CIGS WITH OCNL FOG. GRADUAL CLEARING FROM WEST TO EAST WILL REACH
KBIS-KMOT LINE AFTER 13Z-14Z...AND KJMS AROUND 18Z. INITIAL LOWERING
OF VSBY AND CIG AT THE WESTERN EDGE OF THE LOW STRATUS DECK.
KISN-KDIK EXPECTED TO BE VFR AT FIRST WITH MID CLOUDS MOVING IN FROM
THE WEST. NEXT SYSTEM MOVING IN FROM THE WEST EXPECTED TO BRING
LOWER CIGS AT KISN/KDIK AFT 00Z AND MAY BRING LIGHT SNOW TO KDIK.
DID NOT MENTION YET IN TAFS AS CONFIDENCE THAT EXTENT OF LIGHT SNOW
IN MONTANA/WYOMING WILL REACH KDIK. COLD FRONT ENTERS NORTHWESTERN
NORTH DAKOTA AROUND 00Z IN THE NORTHWEST...MOVES SOUTHEAST REACHING
KJMS AROUND 08Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...JV
LONG TERM...JNS
AVIATION...JV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
637 AM CST WED DEC 24 2014
.UPDATE...
ISSUED AT 637 AM CST WED DEC 24 2014
THE MAIN CHANGE WITH THIS UPDATE WAS TO ADJUST HOURLY FORECAST TEMPS
TO MATCH OBSERVED VALUES IN CENTRAL AND EASTERN LOCATIONS WHERE
TEMPS WERE RUNNING ABOVE FORECAST VALUES DUE TO CLOUD COVER. THE
SAME AREA HAS NUMEROUS REPORTS OF FOG...THOUGH NO SIGNIFICANT
REDUCTIONS IN VISIBILITY AT THIS TIME...GENERALLY 3-5SM VIS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 339 AM CST WED DEC 24 2014
THE MAIN CONCERN IN THE SHORT WILL BE FOG THIS MORNING...THEN
ATTENTION TURNS TO CHANCES OF PRECIPITATION...WITH AND WEATHER TYPE
DURING THE DAY.
CURRENTLY...A WEAK SURFACE RIDGE AXIS EXTENDED ACROSS EASTERN NORTH
DAKOTA - BETWEEN A STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES
AREA AND DEVELOPING LOW PRESSURE IN THE LEE OF THE ROCKIES. ALONG
AND EAST OF THIS RIDGE IS A LARGE STRATUS CLOUD FIELD EXTENDING FROM
THE EASTERN DAKOTAS TO THE GREAT LAKES. IN THE WESTERN DAKOTAS
CIRRUS CLOUDS COVERED MOST OF THE AREA...WITH PATCHY/OCCASIONAL FOG
REPORTED...SOMETIMES LIGHT FOG AND SOMETIMES VISIBILITIES DROP DOWN
TO 1/2 MILE OR LESS FOR SHORT PERIODS.
THE VARIOUS RUNS OF THE HRRR MODEL HAVE SUGGESTED THAT THE WESTERN
EDGE OF THE STRATUS DECK SHOULD ERODE WITH TIME...WITH PATCHY AREAS
OF DENSE FOG FORMING IN THE IMMEDIATE CLEARING OF THE STRATUS.
HOWEVER THE MODEL SUGGESTS THE DENSE FOG NOT LASTING/LINGERING IN
ANY ONE AREA. MEANWHILE INCREASING MID LEVEL CLOUDS MOVING IN FROM
EASTERN MONTANA SHOULD EVENTUALLY LIMIT ANY FOG FORMATION. THUS WILL
KEEP A MENTION OF PATCHY FOG OVER THE WESTERN HALF OF THE STATE
THROUGH AROUND 6 AM...THEN CONTINUE THE PATCHY FOG MENTION OVER ALL
OF CENTRAL NORTH DAKOTA UNTIL AROUND 9 AM.
THE NEXT WEATHER SYSTEM TO AFFECT NORTH DAKOTA IS OVER THE WESTERN
COAST OF NORTH AMERICA EARLY THIS MORNING. BROAD ZONAL FLOW WAS OVER
THE NORTHERN PLAINS AHEAD OF THE SYSTEM WITH LOW PRESSURE IN NORTH
CENTRAL CANADA. THE ZONAL FLOW CONTAINS SOME UPPER LEVEL IMPULSE
ENERGY THAT WAS ASSOCIATED WITH A MID-LEVEL DECK OF CLOUDS OVER
SASKATCHEWAN/MONTANA MOVING EASTWARD...WITH SOME LIGHT RADAR RETURNS
SEEN ON THE RADAR MOSAIC. SURFACE LOW PRESSURE IN THE LEE OF THE
ROCKIES THIS MORNING WILL MOVE EAST ACROSS THE DAKOTAS TODAY. WARM
ADVECTION AHEAD/ALONG THE SYSTEM WAS MOVING INTO WESTERN NORTH
DAKOTA THIS MORNING. THERE IS A SLIGHT CHANCE OF LIGHT PRECIPITATION
WITH THIS UPPER LEVEL ENERGY AS IT MOVES EAST ACROSS THE REGION. THE
MAIN QUESTION IS WHETHER FREEZING RAIN WILL BE AN ISSUE THIS
MORNING. THE APPROACH OF THE MID CLOUD DECK WILL MEAN THAT ICE
CRYSTALS WILL BE LIKELY AT MID AND UPPER LEVELS. SHOULD ANY OF THESE
ICE CRYSTALS FALL INTO LOWER LAYERS OF THE ATMOSPHERE...PROGGED
MODEL SOUNDINGS SUGGEST THAT INITIALLY THERE IS A WARM
LAYER/INVERSION - BUT THAT THE FROST POINT WITHIN THIS LAYER IS MUCH
COOLER THAN THE DRY BULB TEMPERATURE. THUS PARTICLES FALLING THROUGH
SHOULD COOL TOWARDS THE FROST POINT AND REMAIN COOL ENOUGH FOR ALL
SNOW. LATER IN THE DAY AS SURFACE TEMPERATURES WARM ABOVE FREEZING -
MAINLY IN THE WEST - PRECIPITATION WOULD CHANGE TO RAIN.
TONIGHT THE COLD FRONT PORTION OF THE WEATHER SYSTEM WILL MOVE
SOUTHEAST ACROSS THE STATE. AS THIS OCCURS...THE UPPER LEVEL FLOW
BECOMES MORE SOUTHWESTERLY ACROSS THE DAKOTAS - AND THE LEADING EDGE
OF A SERIES OF UPPER LEVEL ENERGY IMPULSES AND MID LEVEL MOISTURE
ARRIVES. BY THIS TIME ANY PRECIPITATION THAT FALLS SHOULD BE IN THE
FORM OF SNOW...OR AT LEAST CHANGING OVER FROM RAIN TO SNOW. MOST OF
THE SNOW SHOULD OCCUR OVER MONTANA AND NORTHERN WYOMING...WITH
SOUTHWESTERN NORTH DAKOTA AND NORTHWESTERN SOUTH DAKOTA RECEIVING
SOME LIGHT SNOW BY CHRISTMAS MORNING. ESTIMATES ARE THAT BY
CHRISTMAS MORNING SNOW AMOUNTS OF AROUND 1/2 INCH WOULD BE COMMON IN
THE SOUTHWEST...MAINLY FROM BEACH TO DICKINSON TO HETTINGER AND
POINTS SOUTH AND WEST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 339 AM CST WED DEC 24 2014
MAIN FORECAST CHALLENGES INVOLVE LIGHT SNOW ACROSS SOUTHERN NORTH
DAKOTA CHRISTMAS DAY AND MUCH COLDER WEATHER BY FRIDAY AND
CONTINUING INTO NEXT WEEK. LATEST 00Z DETERMINISTIC MODELS AS WELL
AS SREF ARE IN GOOD AGREEMENT WITH KEEPING MEASURABLE PRECIP IN THE
FORM OF SNOW ALONG AND SOUTH OF THE ND/SD BORDER ON CHRISTMAS DAY.
THIS INCLUDES THE 00Z NAM WHICH HAS COME BACK IN LINE WITH OTHER
MODEL GUIDANCE WITH A MORE SOUTHWARD LOCATION OF SNOW. MAY SEE
AROUND AN INCH OF SNOW ACCUMULATION CLOSE TO THE STATE BORDER.
WHILE THE SURFACE LOW RESPONSIBLE FOR THIS SNOW MOVES NORTHEAST FROM
THE CENTRAL PLAINS TO THE GREAT LAKES REGION THURSDAY/FRIDAY...
NORTHERLY WINDS WILL ADVECT ARCTIC AIR ACROSS THE NORTHERN PLAINS.
HIGH TEMPS WILL BE IN THE TEENS AND 20S FRIDAY THROUGH THE WEEKEND
BEFORE A STRONGER ARCTIC FRONT PUSHES ACROSS THE REGION EARLY
SUNDAY. SOME DIFFERENCES IN HEIGHT FIELDS DEVELOP BETWEEN
GFS/ECMWF EARLY NEXT WEEK ALTHOUGH BOTH ARE IN AGREEMENT WITH
EXTENSIVE LONG WAVE TROUGH APPROXIMATELY FROM HUDSON BAY TO
INTERMOUNTAIN WEST. GFS HAS -30C CORE AT 850MB OVER NORTHEAST ND
ON TUESDAY WITH THE ECMWF SLIGHTLY WARMER. REGARDLESS...VERY COLD
CONDITIONS EXPECTED WITH WIND CHILLS REACHING DANGEROUS LEVELS
UNDER NORTHWEST FLOW MONDAY NIGHT AND TUESDAY NIGHT WITH 1050MB
SURFACE HIGH SETTING UP OVER WESTERN MONTANA. MAJORITY OF THE CWA
CURRENTLY LOOKS TO REACH WIND CHILL ADVISORY CRITERIA FOR THESE
TIME PERIODS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 637 AM CST WED DEC 24 2014
WIDESPREAD MVFR/IFR WILL CONTINUE FROM KBIS-KMOT-KJMS THIS MORNING
IN CIGS WITH OCNL FOG. GRADUAL CLEARING FROM WEST TO EAST WILL REACH
KBIS-KMOT LINE AFTER 13Z-14Z...AND KJMS AROUND 18Z. INITIAL LOWERING
OF VSBY AND CIG AT THE WESTERN EDGE OF THE LOW STRATUS DECK.
KISN-KDIK EXPECTED TO BE VFR AT FIRST WITH MID CLOUDS MOVING IN FROM
THE WEST. NEXT SYSTEM MOVING IN FROM THE WEST EXPECTED TO BRING
LOWER CIGS AT KISN/KDIK AFT 00Z AND MAY BRING LIGHT SNOW TO KDIK.
DID NOT MENTION YET IN TAFS AS CONFIDENCE THAT EXTENT OF LIGHT SNOW
IN MONTANA/WYOMING WILL REACH KDIK. COLD FRONT ENTERS NORTHWESTERN
NORTH DAKOTA AROUND 00Z IN THE NORTHWEST...MOVES SOUTHEAST REACHING
KJMS AROUND 08Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JNS
SHORT TERM...JV
LONG TERM...JNS
AVIATION...JV
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1014 AM EST WED DEC 24 2014
.SYNOPSIS...
LOW PRESSURE WILL MOVE NORTH OUT OF THE TENNESSEE VALLEY TODAY TO
OHIO AND LAKE ERIE BY THIS EVENING. A TRAILING COLD FRONT WILL SWEEP
EAST ACROSS THE REGION THIS EVENING. STRONG GUSTY WINDS ARE EXPECTED
WITH THIS STORM SYSTEM ACROSS THE AREA. A RIDGE OF HIGH PRESSURE
WILL BUILD NORTH INTO THE REGION BY THURSDAY EVENING. LOW PRESSURE
WILL BUILD NORTHEAST INTO THE NORTHERN LAKES BY SATURDAY FOLLOWED BY
ANOTHER COLD FRONT SATURDAY NIGHT INTO SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ONLY MADE MINOR CHANGES TO THE FORECAST AT THIS TIME.
STRONG 5H JET MOVING UP THE OHIO RIVER VALLEY THIS MORNING. THE
LOW PRESSURE THAT IS OVER SOUTHERN INDIANA WILL CONTINUE TO DEEPEN
AS IT LIFTS NORTH-NORTHEAST THROUGH THE AFTERNOON. AT THIS POINT
THE BETTER LIFT ON THE LEFT FRONT QUAD OF THE JET HAS KEPT MOST OF
THE SHOWERS OVER INDIANA. IT STILL APPEARS THERE WILL BE A LINE OF
LOW TOPPED SHOWERS/THUNDERSTORMS THAT WILL RACE ACROSS THE AREA
NEAR THE COLD FRONT LATE THIS AFTERNOON INTO THE EVENING.
WE WILL CONTINUE TO MONITOR THE LOCATION OF THE LOW LEVEL JET
THAT SHOULD INCREASE THROUGH THE AFTERNOON AS IT LIFTS NORTHWARD
ACROSS CENTRAL OHIO. THE CORE OF THE LOW LEVEL JET LOOKS AS IF IT
WILL BE SLIGHTLY FURTHER EAST THAN PREVIOUS THINKING. WE WILL DIG
INTO THE NEW MODEL RUNS AS THEY ARRIVE AND TWEAK THE WIND
ADVISORY/WARNINGS IF NEEDED.
PREVIOUS DISCUSSION...
THE STORM SYSTEM THAT HAS BEEN ADVERTISED FOR THE LAST WEEK HAS
FINALLY ARRIVED. THE STORM SYSTEM IS PROGGED TO MOVE NORTH OUT OF
THE TENNESSEE VALLEY AREA INTO WESTERN OHIO AND WESTERN LAKE ERIE BY
THIS EVENING. THE MAIN PROBLEM WITH THE SYSTEM WILL BE THE STRONG
DAMAGING WINDS ASSOCIATED WITH THE SYSTEM. STRONG LOW LEVEL JET AND
PRESSURE RISE/FALL COUPLET ALONG THE COLD FRONT WILL ALLOW SOME OF
THE STRONGER WINDS ALOFT TO REACH THE SURFACE. THE WINDOW FOR THE
STRONG WINDS APPEARS THAT IT WILL BE A FAIRLY NARROW TIME FRAME FROM
LATE THIS AFTERNOON THROUGH THURSDAY MORNING. WINDS OF 20 TO 35 MPH
WITH GUSTS AS HIGH AS 60 MPH ARE EXPECTED IN THE WESTERN PORTIONS OF
THE FORECAST AREA AND ALONG THE NORTHEAST LAKE SHORE. SLIGHTLY LOWER
WINDS AND WIND GUSTS ARE EXPECTED ELSEWHERE. THEREFORE...A HIGH
WIND WARNING HAS BEEN ISSUED FOR THE WEST HALF AND IMMEDIATE LAKE
SHORE IN THE NORTHEAST. A WIND ADVISORY HAS BEEN ISSUED FOR THE
REST OF THE EASTERN AREAS.
NEXT PROBLEM IS HOW MUCH RAIN ARE WE GOING TO DEAL WITH. SOME
INDICATIONS ARE THAT THE SHOWERS MAY HOLD OFF UNTIL THIS EVENING
OVER MUCH OF THE AREA. HOWEVER...LATEST RADAR AND HRRR MODEL SUGGEST
SOME SCATTERED SHOWER ACTIVITY THROUGH THE DAY. STORM SYSTEM AND
COLD FRONT SHOULD BRING ANOTHER SWATH OF MOISTURE INTO THE REGION
THIS MORNING AND AGAIN THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
OVERALL UPPER LEVEL PATTERN IS PROGRESSIVE AND FAST MOVING. UPPER
LEVEL TROUGH THAT GENERATED THE CURRENT STORM SYSTEM WILL QUICKLY
CAUSE SURFACE LOW PRESSURE SYSTEM TO QUICKLY VACATE THE AREA ON
THURSDAY. ACTUALLY...SOME WARM AIR ADVECTION IS EXPECTED TO DEVELOP
LATER IN THE DAY ON THURSDAY. THIS SHOULD HELP TO BOOST THE
TEMPERATURES POSSIBLY BACK TO THE LOWER 40S.
SYNOPTIC PRECIPITATION FOR THE MOST PART IS EXPECTED TO PULL OUT TO
THE NORTHEAST FAIRLY QUICKLY WITH THE STORM SYSTEM ON THURSDAY. SOME
LINGERING LAKE EFFECT RAIN/SNOW SHOWERS IS POSSIBLE THURSDAY BEFORE
ENDING.
NEXT STORM SYSTEM APPROACHES THE AREA AND IT WILL MAKE ITS PRESENCE
KNOWN FAIRLY QUICKLY AS EARLY AS SATURDAY. A STORM SYSTEM WILL MOVE
EAST INTO THE WESTERN GREAT LAKES AND DRAG A COLD FRONT ACROSS THE
REGION BY SATURDAY NIGHT. MILD TEMPERATURES SHOULD KEEP
PRECIPITATION IN THE FORM OF RAIN THROUGH THE PERIOD. NOT EXPECTING
ANY MAJOR COOL DOWNS THROUGH MUCH OF THE UPCOMING LAST WEEK OF THE
NEW YEAR. HOWEVER...MODELS ARE HINTING AT A FAIRLY MAJOR COLD AIR
OUT BREAK JUST IN TIME FOR THE NEW YEAR TO ARRIVE. SO FAR THIS LOOKS
TO BE COLDEST AIR OF THE SEASON. DEPENDING ON WHICH MODEL YOU LOOK
AT...THE COLD AIR TAKES A GLANCING BLOW WHILE THE OTHER MODEL SLOWS
THE COLD AIR EXITING OUR AREA.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THE EXTENDED IS NOT CLEAR CUT. ON SUNDAY THE THREAT OF SNOW SHOWERS
WILL BE ENDING FROM THE NORTH AS HIGH PRESSURE BUILDS IN. THE ECMWF
IS SLOWER WITH THE PRECIPITATION DECREASE AND WARMER TO START. AT
THIS TIME KEPT THE THREAT JUST SNOW SHOWERS BUT THIS WILL HAVE TO BE
WATCHED. LATE MONDAY INTO TUESDAY THE MODELS BRING A LOW UP INTO THE
OHIO VALLEY. THE POPS MAY HAVE TO BE RAISED IF THE MODELS KEEP
SHOWING THIS TREND. WENT CLOSE TO WPC GUIDANCE FOR THE TEMPERATURE
FORECAST.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THIS MORNING SOME PATCHES OF LOW CLOUDS...DRIZZLE AND FOG WILL BE
MOVING THROUGH AS A STRONG AND DEEPENING LOW MOVES ALONG THE OHIO
AND INDIANA BORDER THIS AFTERNOON. SOME QUESTION WHETHER CONDITIONS
IMPROVE TO JUST MVFR OR POSSIBLY VFR UNTIL THE FRONT ASSOCIATED
WITH THE LOW SWEEPS ACROSS THE AREA LATE THIS AFTERNOON AND
EVENING. WITH THE FRONT SOME SHOWERS AND ISOLATED THUNDERSTORMS
COULD ACCOMPANY IT. CONFIDENCE IT TOO LOW TO DECIDE WHICH TAF
SITES WOULD HAVE THE THUNDER. SOME STRONG WINDS COULD ALSO OCCUR
WITH THE FRONTAL PASSAGE AND THEN WINDS WILL GUST TO 40 TO 45
KNOTS BEHIND THE FRONT FOR A FEW HOURS WITH ISOLATED GUSTS TO 50
KNOTS WILL ALSO BE POSSIBLE. A DRY SLOT WILL OCCUR AFTER THE
FRONTAL PASSAGE AND THEN A NARROW BAND OF MAINLY SNOW SHOWERS WILL
OCCUR LATE TONIGHT. AT THIS TIME IT SEEMS LIKE IT WILL BE COLD
ENOUGH FOR JUST SNOW. THE VISIBILITY MAY DROP LOWER THEN 3SM FOR A
BRIEF TIME.
.OUTLOOK...NON-VFR LIKELY INTO THURSDAY. NON-VFR DEVELOPING AGAIN
SATURDAY AND CONTINUING SUNDAY.
&&
.MARINE...
WINDS WILL BE ON THE INCREASE ON THE LAKE ESPECIALLY THIS AFTERNOON
AFTER THE LOW MOVES NORTH AND THE COLD FRONT MOVES THROUGH. SOME
QUESTION ON THE EXACT TIMING OF WHEN THE GALE FORCE WINDS WILL
START. WILL HAVE THE GALE WARNING START ON THE WEST END AT 22Z AND
ON THE EAST END AT 02Z. WE ALSO COULD HAVE A SQUALL LINE MOVE
THROUGH LATE THIS AFTERNOON AND EVENING WITH HIGH WINDS. THE LOW
MOVES QUICK SO THIS WILL BE A QUICK SHOT OF GALE FORCE WINDS. SOME
CONCERN WITH THE 925 MB WINDS ON THE LAKE OVER 50 KNOTS...THE COLD
ADVECTION IS SOMEWHAT GRADUAL SO GOING WITH SUSTAINED OF 40 TO 45
KNOTS WITH HIGHER GUSTS. BECAUSE OF THE GALE FORCE WINDS THE WATER
LEVEL WILL DROP ON THE WEST END OF THE LAKE LATE THIS EVENING...A
LOW WATER ADVISORY WILL BE ISSUED. ONCE THE GALE DECREASE LATE
THURSDAY A SMALL CRAFT ADVISORY WILL BE NEEDED ON THE EAST END.
A MODERATE SOUTHWEST FLOW WILL CONTINUE ON THE LAKE FOR FRIDAY AND
SATURDAY. IT IS IN WARM ADVECTION SO WE MAY NOT NEED A SMALL CRAFT
ADVISORY ON THE LAKE. A COLD FRONT MOVES THROUGH LATE SATURDAY AND
WE MAY NEED A SMALL CRAFT ADVISORY ON THE EAST END OF THE LAKE IN
THE COLD ADVECTION. IT WILL BE SHORT LIVED AS HIGH PRESSURE BUILDS
IN QUICKLY ON SUNDAY. FOR EARLY NEXT WEEK THE FLOW ON THE LAKE WILL
BE EAST AND LIGHT AND LOW PRESSURE MOVES THROUGH THE OHIO VALLEY AND
HIGH PRESSURE IS OVER CANADA.
&&
.CLIMATE...
TEMPERATURES TODAY WILL ATTEMPT TO SURGE INTO THE 60S AND MAY
APPROACH RECORD LEVELS. THE CURRENT RECORDS ARE:
CLEVELAND 65 1964 AKRON-CANTON 63 1964
ERIE 66 1964 MANSFIELD 62 1964
TOLEDO 65 1889 YOUNGSTOWN 63 1982
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...HIGH WIND WARNING FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY
FOR OHZ012-089.
WIND ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY FOR
OHZ013-014-021>023-031>033-038.
HIGH WIND WARNING FROM 3 PM THIS AFTERNOON TO 4 AM EST
THURSDAY FOR OHZ003-006>011-017>020-027>030-036-037-047.
PA...HIGH WIND WARNING FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY
FOR PAZ001.
WIND ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY FOR
PAZ002-003.
MARINE...GALE WARNING FROM 9 PM THIS EVENING TO 4 PM EST THURSDAY FOR
LEZ061-145>149-165>169.
LOW WATER ADVISORY FROM 9 PM THIS EVENING TO NOON EST THURSDAY
FOR LEZ142>144-162>164.
GALE WARNING FROM 5 PM THIS AFTERNOON TO 10 AM EST THURSDAY
FOR LEZ142>144-162>164.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY/MULLEN
SHORT TERM...LOMBARDY
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
CLIMATE...
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
658 AM EST WED DEC 24 2014
.SYNOPSIS...
LOW PRESSURE WILL MOVE NORTH OUT OF THE TENNESSEE VALLEY TODAY TO
OHIO AND LAKE ERIE BY THIS EVENING. A TRAILING COLD FRONT WILL SWEEP
EAST ACROSS THE REGION THIS EVENING. STRONG GUSTY WINDS ARE EXPECTED
WITH THIS STORM SYSTEM ACROSS THE AREA. A RIDGE OF HIGH PRESSURE
WILL BUILD NORTH INTO THE REGION BY THURSDAY EVENING. LOW PRESSURE
WILL BUILD NORTHEAST INTO THE NORTHERN LAKES BY SATURDAY FOLLOWED BY
ANOTHER COLD FRONT SATURDAY NIGHT INTO SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MINOR CHANGES TO REDUCE PRECIPITATION TO CHANCE POPS FOR THIS
MORNING. NEXT SURGE OF SHOWER ACTIVITY WILL COME THIS AFTERNOON
AS LOW PRESSURE SYSTEM PASSES OVER THE REGION AND COLD FRONT
SWEEPS EAST.
TEMPERATURES CONTINUE TO HOLD NEARLY STEADY AND SHOULD BEGIN TO
SLOWLY CLIMB AFTER SUNRISE.
PREVIOUS DISCUSSION...
THE STORM SYSTEM THAT HAS BEEN ADVERTISED FOR THE LAST WEEK HAS
FINALLY ARRIVED. THE STORM SYSTEM IS PROGGED TO MOVE NORTH OUT OF
THE TENNESSEE VALLEY AREA INTO WESTERN OHIO AND WESTERN LAKE ERIE BY
THIS EVENING. THE MAIN PROBLEM WITH THE SYSTEM WILL BE THE STRONG
DAMAGING WINDS ASSOCIATED WITH THE SYSTEM. STRONG LOW LEVEL JET AND
PRESSURE RISE/FALL COUPLET ALONG THE COLD FRONT WILL ALLOW SOME OF
THE STRONGER WINDS ALOFT TO REACH THE SURFACE. THE WINDOW FOR THE
STRONG WINDS APPEARS THAT IT WILL BE A FAIRLY NARROW TIME FRAME FROM
LATE THIS AFTERNOON THROUGH THURSDAY MORNING. WINDS OF 20 TO 35 MPH
WITH GUSTS AS HIGH AS 60 MPH ARE EXPECTED IN THE WESTERN PORTIONS OF
THE FORECAST AREA AND ALONG THE NORTHEAST LAKE SHORE. SLIGHTLY LOWER
WINDS AND WIND GUSTS ARE EXPECTED ELSEWHERE. THEREFORE...A HIGH
WIND WARNING HAS BEEN ISSUED FOR THE WEST HALF AND IMMEDIATE LAKE
SHORE IN THE NORTHEAST. A WIND ADVISORY HAS BEEN ISSUED FOR THE
REST OF THE EASTERN AREAS.
NEXT PROBLEM IS HOW MUCH RAIN ARE WE GOING TO DEAL WITH. SOME
INDICATIONS ARE THAT THE SHOWERS MAY HOLD OFF UNTIL THIS EVENING
OVER MUCH OF THE AREA. HOWEVER...LATEST RADAR AND HRRR MODEL SUGGEST
SOME SCATTERED SHOWER ACTIVITY THROUGH THE DAY. STORM SYSTEM AND
COLD FRONT SHOULD BRING ANOTHER SWATH OF MOISTURE INTO THE REGION
THIS MORNING AND AGAIN THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
OVERALL UPPER LEVEL PATTERN IS PROGRESSIVE AND FAST MOVING. UPPER
LEVEL TROUGH THAT GENERATED THE CURRENT STORM SYSTEM WILL QUICKLY
CAUSE SURFACE LOW PRESSURE SYSTEM TO QUICKLY VACATE THE AREA ON
THURSDAY. ACTUALLY...SOME WARM AIR ADVECTION IS EXPECTED TO DEVELOP
LATER IN THE DAY ON THURSDAY. THIS SHOULD HELP TO BOOST THE
TEMPERATURES POSSIBLY BACK TO THE LOWER 40S.
SYNOPTIC PRECIPITATION FOR THE MOST PART IS EXPECTED TO PULL OUT TO
THE NORTHEAST FAIRLY QUICKLY WITH THE STORM SYSTEM ON THURSDAY. SOME
LINGERING LAKE EFFECT RAIN/SNOW SHOWERS IS POSSIBLE THURSDAY BEFORE
ENDING.
NEXT STORM SYSTEM APPROACHES THE AREA AND IT WILL MAKE ITS PRESENCE
KNOWN FAIRLY QUICKLY AS EARLY AS SATURDAY. A STORM SYSTEM WILL MOVE
EAST INTO THE WESTERN GREAT LAKES AND DRAG A COLD FRONT ACROSS THE
REGION BY SATURDAY NIGHT. MILD TEMPERATURES SHOULD KEEP
PRECIPITATION IN THE FORM OF RAIN THROUGH THE PERIOD. NOT EXPECTING
ANY MAJOR COOL DOWNS THROUGH MUCH OF THE UPCOMING LAST WEEK OF THE
NEW YEAR. HOWEVER...MODELS ARE HINTING AT A FAIRLY MAJOR COLD AIR
OUT BREAK JUST IN TIME FOR THE NEW YEAR TO ARRIVE. SO FAR THIS LOOKS
TO BE COLDEST AIR OF THE SEASON. DEPENDING ON WHICH MODEL YOU LOOK
AT...THE COLD AIR TAKES A GLANCING BLOW WHILE THE OTHER MODEL SLOWS
THE COLD AIR EXITING OUR AREA.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THE EXTENDED IS NOT CLEAR CUT. ON SUNDAY THE THREAT OF SNOW SHOWERS
WILL BE ENDING FROM THE NORTH AS HIGH PRESSURE BUILDS IN. THE ECMWF
IS SLOWER WITH THE PRECIPITATION DECREASE AND WARMER TO START. AT
THIS TIME KEPT THE THREAT JUST SNOW SHOWERS BUT THIS WILL HAVE TO BE
WATCHED. LATE MONDAY INTO TUESDAY THE MODELS BRING A LOW UP INTO THE
OHIO VALLEY. THE POPS MAY HAVE TO BE RAISED IF THE MODELS KEEP
SHOWING THIS TREND. WENT CLOSE TO WPC GUIDANCE FOR THE TEMPERATURE
FORECAST.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THIS MORNING SOME PATCHES OF LOW CLOUDS...DRIZZLE AND FOG WILL BE
MOVING THROUGH AS A STRONG AND DEEPENING LOW MOVES ALONG THE OHIO
AND INDIANA BORDER THIS AFTERNOON. SOME QUESTION WHETHER CONDITIONS
IMPROVE TO JUST MVFR OR POSSIBLY VFR UNTIL THE FRONT ASSOCIATED
WITH THE LOW SWEEPS ACROSS THE AREA LATE THIS AFTERNOON AND
EVENING. WITH THE FRONT SOME SHOWERS AND ISOLATED THUNDERSTORMS
COULD ACCOMPANY IT. CONFIDENCE IT TOO LOW TO DECIDE WHICH TAF
SITES WOULD HAVE THE THUNDER. SOME STRONG WINDS COULD ALSO OCCUR
WITH THE FRONTAL PASSAGE AND THEN WINDS WILL GUST TO 40 TO 45
KNOTS BEHIND THE FRONT FOR A FEW HOURS WITH ISOLATED GUSTS TO 50
KNOTS WILL ALSO BE POSSIBLE. A DRY SLOT WILL OCCUR AFTER THE
FRONTAL PASSAGE AND THEN A NARROW BAND OF MAINLY SNOW SHOWERS WILL
OCCUR LATE TONIGHT. AT THIS TIME IT SEEMS LIKE IT WILL BE COLD
ENOUGH FOR JUST SNOW. THE VISIBILITY MAY DROP LOWER THEN 3SM FOR A
BRIEF TIME.
.OUTLOOK...NON-VFR LIKELY INTO THURSDAY. NON-VFR DEVELOPING AGAIN
SATURDAY AND CONTINUING SUNDAY.
&&
.MARINE...
WINDS WILL BE ON THE INCREASE ON THE LAKE ESPECIALLY THIS AFTERNOON
AFTER THE LOW MOVES NORTH AND THE COLD FRONT MOVES THROUGH. SOME
QUESTION ON THE EXACT TIMING OF WHEN THE GALE FORCE WINDS WILL
START. WILL HAVE THE GALE WARNING START ON THE WEST END AT 22Z AND
ON THE EAST END AT 02Z. WE ALSO COULD HAVE A SQUALL LINE MOVE
THROUGH LATE THIS AFTERNOON AND EVENING WITH HIGH WINDS. THE LOW
MOVES QUICK SO THIS WILL BE A QUICK SHOT OF GALE FORCE WINDS. SOME
CONCERN WITH THE 925 MB WINDS ON THE LAKE OVER 50 KNOTS...THE COLD
ADVECTION IS SOMEWHAT GRADUAL SO GOING WITH SUSTAINED OF 40 TO 45
KNOTS WITH HIGHER GUSTS. BECAUSE OF THE GALE FORCE WINDS THE WATER
LEVEL WILL DROP ON THE WEST END OF THE LAKE LATE THIS EVENING...A
LOW WATER ADVISORY WILL BE ISSUED. ONCE THE GALE DECREASE LATE
THURSDAY A SMALL CRAFT ADVISORY WILL BE NEEDED ON THE EAST END.
A MODERATE SOUTHWEST FLOW WILL CONTINUE ON THE LAKE FOR FRIDAY AND
SATURDAY. IT IS IN WARM ADVECTION SO WE MAY NOT NEED A SMALL CRAFT
ADVISORY ON THE LAKE. A COLD FRONT MOVES THROUGH LATE SATURDAY AND
WE MAY NEED A SMALL CRAFT ADVISORY ON THE EAST END OF THE LAKE IN
THE COLD ADVECTION. IT WILL BE SHORT LIVED AS HIGH PRESSURE BUILDS
IN QUICKLY ON SUNDAY. FOR EARLY NEXT WEEK THE FLOW ON THE LAKE WILL
BE EAST AND LIGHT AND LOW PRESSURE MOVES THROUGH THE OHIO VALLEY AND
HIGH PRESSURE IS OVER CANADA.
&&
.CLIMATE...
TEMPERATURES TODAY WILL ATTEMPT TO SURGE INTO THE 60S AND MAY
APPROACH RECORD LEVELS. THE CURRENT RECORDS ARE:
CLEVELAND 65 1964 AKRON-CANTON 63 1964
ERIE 66 1964 MANSFIELD 62 1964
TOLEDO 65 1889 YOUNGSTOWN 63 1982
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...HIGH WIND WARNING FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY
FOR OHZ012-089.
WIND ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY FOR
OHZ013-014-021>023-031>033-038.
HIGH WIND WARNING FROM 3 PM THIS AFTERNOON TO 4 AM EST
THURSDAY FOR OHZ003-006>011-017>020-027>030-036-037-047.
PA...HIGH WIND WARNING FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY
FOR PAZ001.
WIND ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY FOR
PAZ002-003.
MARINE...GALE WARNING FROM 9 PM THIS EVENING TO 4 PM EST THURSDAY FOR
LEZ061-145>149-165>169.
LOW WATER ADVISORY FROM 9 PM THIS EVENING TO NOON EST THURSDAY
FOR LEZ142>144-162>164.
GALE WARNING FROM 5 PM THIS AFTERNOON TO 10 AM EST THURSDAY
FOR LEZ142>144-162>164.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
CLIMATE...
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1001 AM CST WED DEC 24 2014
.UPDATE...
CURRENT RADAR SHOWS RAIN/SHOWERS MOVING INTO NE PORTION OF OUR CWA.
WILL LOWER POPS OVER THE W/NW COUNTIES...BUT LATEST HRRR SUGGESTS
ONE MORE ROUND OF SCATTERED LIGHT SHOWERS THIS AFTERNOON SO WILL NOT
DROP POPS COMPLETELY. VISIBLE SATELLITE SHOWS A THIN ZONE OF
CLEARING APPROACHING WESTERN COUNTIES. CLEARING MAY BE SHORT-LIVED
AS ADDITIONAL CLOUD IS COVER WORKING ITS WAY EAST THROUGH ARKANSAS.
WILL MAKE MINOR ADJUSTMENTS TO SKY FOR THIS AFTERNOON. WILL HOLD OFF
ON ANY CHANGES TO LATER PERIODS UNTIL ALL 12Z GUIDANCE ARRIVES.
UPDATED FORECASTS/GRIDS OUT SHORTLY.
GW
&&
.PREV DISCUSSION... /ISSUED 318 AM CST WED DEC 24 2014/
DISCUSSION...
CURRENTLY A COLD FRONT WAS JUST EAST OF THE CWA WITH LIGHT
NORTHWEST WINDS AND TEMPERATURES GENERALLY IN THE MID AND UPPER
40S OVER THE AREA. RAIN...WITH A LIFTING SECOND WAVE IN THE
ARKLATEX...WAS BREAKING OUT OVER CENTRAL AND EASTERN
ARKANSAS. OTHERWISE POINTS EAST WERE CLOUDY WITH PATCHY FOG.
FOR TODAY AND TONIGHT...UPPER LEVEL TROUGH OVER THE OZARKS WILL
CONTINUE TO LIFT NORTHEAST THROUGH THE DAY AND SHEAR SOME AS IT
DOES. RAIN CHANCES WILL CONTINUE THIS MORNING THEN SLOWLY END FROM
SOUTHWEST TO NORTHEAST IN THE AFTERNOON. SKIES WILL BECOME PARTLY
CLOUDY LATE TONIGHT FROM WEST TO EAST. APPEARS THE GREATEST RISK
FOR PATCHY FOG WILL BE OVER THE EAST AFTER MIDNIGHT...WHERE
HEAVIER AMOUNTS OF RAIN FELL YESTERDAY.
CHRISTMAS DAY AND FRIDAY...NOT MUCH CHANGE NEEDED THIS PERIOD AS
MODELS SHOW THE UPPER FLOW STARTING OFF WESTERLY AND THEN QUICKLY
SHIFTING BACK SOUTHWESTERLY. LOW LEVELS WILL ALSO QUICKLY BECOME
SOUTHERLY WITH A FEW GUSTS STARTING CHRISTMAS AFTERNOON AND
PERSISTING THROUGH FRIDAY. A MIX OF CLOUDS AND SUN SHOULD BUMP
TEMPERATURES INTO THE 50S THURSDAY...AND WITH STRONGER WAA FRIDAY
MAYBE THE LOWER 60S FOR SOME. THOUGH THERE MAY BE A STRAY SHOWER
WEST OF THE MS RIVER FRIDAY AFTERNOON BETTER MOISTURE IS PROGGED
TO COME INTO THE MIDSOUTH FRIDAY NIGHT. LOWS WILL ALSO BE MILDER.
SATURDAY AND SUNDAY...THE EURO AND GFS BOTH SHOW A MOIST UPPER
LEVEL FLOW OVER A PASSING COLD FRONT. THUS TEMPERATURES WILL
BECOME COOL AGAIN...SKIES CLOUDY AND RAIN REMAINING IN THE
FORECAST. A DISTINCT SHORTWAVE MOVING IN THE FLOW ON SUNDAY MAY
SPARK A FEW HEAVIER SHOWERS SOUTH OF INTERSTATE FORTY...BUT FOR
NOW LEFT OUT ANY MENTION OF THUNDER AS BY THIS TIME LIFT ALONG THE
FRONT WILL BE WELL TO OUR SOUTHEAST.
MONDAY AND TUESDAY...PRECIPITATION CHANCES WILL DIMINISH SOME THIS
PERIOD AS DEEPER ARCTIC AIR MOVES SOUTHEAST OUT OF THE CENTRAL
PLAINS. HIGH TEMPERATURES WILL RUN APPROXIMATELY FIVE DEGREES
BELOW NORMAL MONDAY...AND CLOSER TO TEN DEGREES BY TUESDAY. A
DISTURBANCE LATE TUESDAY MAY TRIGGER A THREAT FOR LIGHT SNOW OVER
THE NORTHERN HALF OF THE AREA...BUT THERE IS PLENTY OF TIME TO SEE
IF THIS THREAT WILL MATERIALIZE INTO ANYTHING.
JAB
&&
.AVIATION...
12Z TAF CYCLE
IFR CIGS SHOULD PERSIST THIS MORNING INTO EARLY AFTERNOON AT
KMEM...KMKL...AND KTUP. NUMEROUS RAIN SHOWERS WILL ALSO CONTINUE
AT ALL SITES. MVFR CIGS WILL BE COMMON THIS MORNING AT KJBR. THERE
WILL BE A GRADUAL IMPROVEMENT TO MVFR CIGS LATER THIS AFTERNOON AT
ALL SITES WHICH SHOULD CONTINUE INTO THIS EVENING. WINDS WILL PICK
UP FROM THE NORTHWEST AND WEST TODAY AND GUST AT ALL TAF SITES.
MVFR CIGS WILL EVENTUALLY SCATTER OUT OVERNIGHT WITH RAIN ENDING
AND WINDS DIMINISHING. THIS MAY SET THE STAGE FOR SOME MVFR/IFR
VSBYS IN FOG LATE TONIGHT AT KMKL AND KTUP.
JLH
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1005 AM CST WED DEC 24 2014
.UPDATE...THIS AFTERNOON
ISSUED AT 1005 AM CST WED DEC 24 2014
WATER VAPOR SHOWS A SHORT WAVE TROUGH MOVING NORTH NORTHEAST
THROUGH CENTRAL ILLINOIS. THIS WAVE WILL HELP TO KEEP SOME WEAK
900 TO 800 MB FRONTOGENESIS ACROSS CENTRAL AND NORTH CENTRAL
WISCONSIN AND PARTS OF SOUTHWEST WISCONSIN. SOUNDINGS SHOW THAT
THERE WILL BE SOME ICE CRYSTAL SEEDING FROM ALOFT...SO EXPECT
MAINLY SNOW. LITTLE...IF ANY...ACCUMULATION IS EXPECTED. DUE TO
THIS...INCREASE THE SNOW CHANCES UP INTO THE 20 TO 30 PERCENT
RANGE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CST WED DEC 24 2014
THE MAIN FOCUS FOR TODAY IS WITH THE CHANCES FOR SNOW/DRIZZLE.
CURRENTLY...A SHEARED OUT/POSITIVELY TILTED MID LEVEL CLOSED
TROUGH EXTENDS FROM THE UPPER MISSISSIPPI RIVER VALLEY ON DOWN TO
THE WESTERN GULF WITH THE SHEAR AXIS RIGHT OVER WEST CENTRAL
WISCONSIN/EASTERN IOWA. AT THE SURFACE...A LOW/TROUGH IS CENTERED
OVER SOUTHEAST WISCONSIN WITH NORTHWESTERLY FLOW RUNNING ACROSS
THE REGION ON THE BACK SIDE OF THIS SYSTEM. NOT MUCH IN THE WAY OF
COLD AIR BEHIND IT WITH 850MB TEMPERATURES AROUND -5C.
PRECIPITATION-WISE...DRIZZLE HAS DEVELOPED IN A BAND NORTHWEST OF
THE SURFACE LOW AND ALONG THE MID LEVEL SHEAR AXIS ALONG THE
TROUGH. 24.06Z RAP SOUNDINGS FROM ALONG THIS BAND SHOW THAT THERE
IS A LACK OF ICE ALOFT WITH SATURATED LOW LEVELS. THESE SOUNDINGS
SHOW SOME COOLING AROUND 700MB WHICH COULD PUSH THE SATURATED
LAYER DOWN INTO THE -8C RANGE AND PERHAPS CAUSE A CHANGE OVER TO
LIGHT SNOW. WITH FORCING WEAK...EXPECT THAT DRIZZLE WILL BE THE
MAIN PRECIPITATION TYPE WITH IMPACTS MINIMAL THANKS TO SURFACE
TEMPERATURES AT 32 TO 36F. THE 24.06Z HRRR/RAP TAKES THIS MAIN
BAND EASTWARD THROUGH THE MORNING AND DIMINISHING ALONG THE WAY.
AS THE TROUGH/LOW SHIFT OFF TO THE EAST TONIGHT...MID
LEVEL/SURFACE RIDGING WILL PUSH IN FROM THE WEST AND MAY OFFER A
BRIEF PERIOD WHERE SKIES CLEAR OUT LATE TONIGHT. HAVE PLAYED SKY
COVER ON THE PESSIMISTIC SIDE SINCE AS SOON AS THE LOW LEVEL
MOISTURE SHIFTS EAST...SOME HIGH LEVEL CLOUD COVER APPEARS TO MOVE
IN ACCORDING TO THE 24.00Z NAM/GFS. TEMPERATURES WILL NOT DIVE
MUCH TONIGHT WITH LOWS ONLY IN THE MID 20S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 326 AM CST WED DEC 24 2014
THE FOCUS THEN SHIFTS TO PRECIPITATION CHANCES WITH THE NEXT
SYSTEM TO MOVE IN ON THURSDAY INTO FRIDAY NIGHT. RETURN SOUTHERLY
LOW LEVEL FLOW WILL BRING WARMER AIR UP FROM THE SOUTHERN PLAINS.
THERE HAS BEEN A FAIRLY CONSISTENT MESSAGE FROM THE 24.00Z AND
PREVIOUS MODELS RUNS THAT SHOW A 900-800MB FRONTOGENETIC BAND
DEVELOPING THURSDAY AFTERNOON ACROSS CENTRAL MINNESOTA INTO
NORTHERN WISCONSIN. LOCALLY...24.00Z NAM/GFS ARE SHOWING SOME LOW
LEVEL SATURATION WITH THE WARM AIR ADVECTION TAKING PLACE THURSDAY
NIGHT. IF FORCING WAS A BIT STRONGER IN THE LOW LEVELS...THERE
WOULD BE THE POTENTIAL TO GET SOME DRIZZLE TO FORM BUT AT THE
MOMENT IT LOOKS TOO WEAK.
BROAD MID LEVEL TROUGHING WILL MOVE INTO THE REGION FRIDAY/FRIDAY
NIGHT AND BRING THE NEXT BEST CHANCE FOR SOME SNOW AS IT COMES
THROUGH. AS THE DEEPER LIFT COMES IN WITH A MID LEVEL SHORT WAVE
TROUGH TRACKING THROUGH IOWA...SNOW SHOULD DEVELOP IN A SOUTHWEST
TO NORTHEAST BAND. WITH QPF AMOUNTS AROUND A TENTH OF AN INCH OR
LESS...EXPECT THAT ANY ACCUMULATIONS WILL BE MINOR AT AN INCH OR
LESS.
THE PASSING OF THIS TROUGH WILL MARK A PERIOD OF COLDER AIR
ADVANCING INTO THE REGION FROM CANADA. A VERY CONSISTENT SIGNAL IN
THE 24.00Z GFS/ECMWF IS WITH ANOTHER WAVE OF COLDER AIR MOVING
DOWN FROM NORTHERN CANADA FOR THE MIDDLE PART OF NEXT WEEK WITH
850MB TEMPERATURES FORECAST TO DROP TO -20C OR LOWER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 535 AM CST WED DEC 24 2014
A LINGERING TROUGH OF LOW PRESSURE IS PRODUCING AREAS OF -SN/-DZ
THIS MORNING. LOOKING FOR THIS TO END AT KRST AROUND 16Z AND AROUND
18Z FOR KLSE. OTHERWISE...IFR CIGS TO CONTINUE AT KRST THROUGH THE
PERIOD WITH KLSE EXPECTED TO BE ON THE BORDERLINE OF MVFR/IFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BOYNE
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DAS
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1002 AM CST WED DEC 24 2014
.UPDATE...
LATEST NAM AND HRRR CONTINUE TO SHOW LESS PRECIP FOR SOUTHERN
WISCONSIN TODAY. WITH SATURATION STRUGGLING UP TO AROUND
-10C...ANY PRECIP THAT DOES MOVE THROUGH WILL PROBABLY BE EITHER
LIGHT SNOW OR LIGHT RAIN. SEEING THIS MIX RIGHT NOW TO THE WEST.
AT THIS POINT...NO APPRECIABLE RAIN OR SNOW IS EXPECTED AS
DEEPENING LOW PRESSURE LIFTS NORTH WELL TO THE EAST OF THE
FORECAST AREA. WILL PROBABLY NEED TO CUT BACK ON POPS FOR THE
REMAINDER OF THE DAY. LIGHT PRECIP WILL WIND DOWN BY THE LATE
EVENING HOURS.
VISIBILITIES CONTINUE TO IMPROVE ACROSS THE FORECAST AREA THIS
MORNING...SO WILL ALLOW THE DENSE FOG ADVISORY TO EXPIRE AT 10 AM.
&&
.AVIATION/18Z TAFS/...
LATEST MODELS CONTINUE TO THE DOWNWARD TREND IN PRECIP
CHANCES...WITH NO APPRECIABLE RAIN OR SNOW EXPECTED THROUGH THE
REMAINDER OF THE DAY. STILL MAY SEE A LITTLE LIGHT SNOW OR RAIN AT
TIMES INTO THE EVENING HOURS AS THE UPPER THROUGH SWINGS THROUGH.
VISIBILITIES WILL CONTINUE TO IMPROVE THROUGH LATE
MORNING...THOUGH LOW CLOUDS WILL LIKELY PERSIST INTO TONIGHT.
SHOULD SEE A RETURN TO VFR CONDITIONS BY MID OR LATE THURSDAY
MORNING.
&&
.MARINE...
WILL FURTHER DELAY START OF SMALL CRAFT ADVISORY UNTIL 00Z.
FARTHER EAST TRACK OF LOW PRESSURE MOVING NORTHEAST TOWARD
THE CENTRAL GREAT LAKES DELAYING TIGHTENING PRESSURE GRADIENT OVER
LAKE MICHIGAN. HENCE NOT EXPECTING GUSTY NORTHWEST WINDS TO DEVELOP
UNTIL TONIGHT. SHIP REPORT EAST OF RACINE AT EDGE OF NEARSHORE
WATERS HAD SUSTAINED WINDS OF 12 KT.
&&
.PREV DISCUSSION... /ISSUED 342 AM CST WED DEC 24 2014/
SHORT TERM...
THE 00Z NAM/GFS AND ECMWF HAVE TRENDED EAST WITH LOW EXPECTED TO
TRACK ALONG IN/OH BORDER AND INTO SOUTHEAST MICHIGAN. RAPID
DEEPENING PHASE OF ABOUT 1 MB/HOUR EXPECTED TO START IN THE
MORNING IN OHIO VALLEY AND CONTINUES INTO THE EVENING AS STORM
CROSSES SOUTHEAST MICHIGAN AND BOUND FOR GEORGIAN BAY.
WILL CONTINUE THE PREVIOUS IDEA OF LOWERING THE ACCUMULATING SNOW
AND HAVE CANCELLED THE WINTER WEATHER ADVISORIES. NAM FORECAST
SOUNDINGS SHOW A FAIRLY DRY LAYER FROM 4 TO 13 THSD FT EARLY THIS
MORNING OVER THE FAR SOUTHEAST. THIS DIMINISHES...BUT DEEP
SATURATION IS RATHER BRIEF LATE THIS MORNING AND EARLY AFTERNOON
BEFORE DRYING OCCURS AROUND 10 THSD FT EARLY THIS EVENING. SNOW
RATIOS ARE RATHER LOW IN THE FAR EAST WHERE THE PRECIPITATION WOULD
BE MORE. THE 12Z ECMWF HAS LITTLE IF ANY MEASURABLE PRECIPITATION
OVER SOUTHEAST WISCONSIN. THE HRRR IS THE MOST AGGRESSIVE MESO MODEL
WITH AROUND 0.15 OF PRECIPITATION OVER THE LAKESHORE COUNTIES.
HOWEVER EVEN THIS WOULD BE LIMITED DUE TO THE CONSENSUS 6 TO 1 SNOW
RATIOS.
THE NEW 06Z NAM CONTIUES THE EASTWARD TREND AND NOW AGREES WITH THE
ECMWF WITH LITTLE IN THE WAY OF MEASURABLE PRECIPITATION OVER
EASTERN WISCONSIN.
CHRISTMAS DAY...FORECAST CONFIDENCE HIGH.
HIGH PRESSURE CENTERED OVER THE GULF COASTAL STATES WILL STRETCH ITS
AXIS UP INTO THE GREAT LAKES FOR CHRISTMAS...BRINGING A DRY AND
RATHER PLEASANT DAY WITH HIGHS IN THE MID TO UPPER 30S. WE MIGHT
EVEN SEE A LITTLE SUNSHINE.
LONG TERM...
FRIDAY THROUGH SATURDAY... FORECAST CONFIDENCE MEDIUM.
FRIDAY WEATHER WILL REMAIN QUIET AND MILD OVER SOUTHERN WI. HIGHS
ARE EXPECTED IN THE LOWER 40S WITH A SOUTHERLY BREEZE. THERE WILL
LIKELY BE LOW CLOUDS AROUND DUE TO THE LOW LEVEL MOISTURE SPREADING
BACK INTO THE REGION.
A WEAK SURFACE LOW PRESSURE TROUGH AND COLD FRONT WILL SLIDE THROUGH
SOUTHERN WI FRIDAY NIGHT. MEANWHILE... A 500MB SHORTWAVE WITHIN THE
LEFT EXIT REGION OF A STRENGTHENING UPPER JET WILL BE TRACKING
THROUGH CENTRAL AND NORTHERN WI. MODELS ARE SHOWING TWO AREAS OF
PRECIP ASSOCIATED WITH THIS SYSTEM... ONE MAINLY IN IL THAT CLIPS
SOUTHEAST WI AND THE OTHER OVER THE NORTHWEST HALF OF WI. THE MKX
FORECAST AREA WILL LAND BETWEEN THESE TWO FAVORED AREAS. THE GFS AND
NOW THE 06Z NAM SHOW THESE TWO AREAS CLEARLY IN THE QPF FIELD AND
THE ECMWF DOES TO A LESSER EXTENT.
TEMPERATURE PROFILES SHOW THAT MOST OF THE PRECIP IN SOUTHEAST WI
WILL FALL AS RAIN AND THEN GRADUALLY CHANGE OVER TO SNOW OVERNIGHT
INTO SATURDAY MORNING BEFORE ENDING. IN THE NORTHERN FORECAST
AREA... THE TEMP PROFILE IS COLDER AND WE ARE LOOKING AT A RAIN/SNOW
MIX CHANGING OVER TO SNOW BY MIDNIGHT. PRECIP AMOUNTS WILL BE
LIGHT... LESS THAN A TENTH OF AN INCH. ANY SNOW ACCUMULATION WOULD
BE LESS THAN A HALF INCH.
THE ECWMF HANGS ONTO THE LIGHT PRECIP LONGER IN SOUTHEAST WI THAN
THE GFS ON SATURDAY. COLD AIR ADVECTION AND CLOUDS WILL LEAD TO
STEADY TEMPS AROUND 30 THROUGH THE DAY.
SUNDAY THROUGH TUESDAY... FORECAST CONFIDENCE HIGH.
SURFACE HIGH PRESSURE AND DRY WEATHER WILL DOMINATE FOR SUNDAY AND
MONDAY... BUT TEMPERATURES WILL BE BELOW AVERAGE.
ANOTHER BROAD TROUGH WILL CROSS THE COUNTRY EARLY NEXT WEEK AND MAY
BRING SOME LIGHT SNOW ACROSS WISCONSIN ON A SHORTWAVE MONDAY NIGHT
INTO TUESDAY.
THEN A DEEPER UPPER LEVEL TROUGH IS FORECAST TO DROP DOWN FROM
CANADA THROUGH THE UPPER MIDWEST AND BRING JANUARY-LIKE TEMPERATURES
INTO THE REGION FOR THE NEW YEAR.
AVIATION/12Z TAFS/...
EXPECT IFR/LIFR CIGS OVER MUCH OF SOUTH CENTRAL AND PORTIONS OF
SOUTHEAST WISCONSIN. LIFR FOG EXPECTED TO PERSIST FOR A FEW HOURS
AFTER SUNRISE OVER PORTIONS OF SOUTH CENTRAL WISCONSIN.
OVER THE FAR SOUTHEAST IFR CIGS POSSIBLE LATER THIS MORNING AND
AFTERNOON. DUE TO THE EXPECTED MIX OF RAIN AND SNOW FAR EAST
TEMPERATURES IN THE MID TO UPPER 30S AT SURFACE MAY PREVENT
SIGNIFICANT CHANGEOVER AND PAVEMENT MAY REMAIN MAINLY WET THROUGH
THE PRECIPITATION DURATION. HOWEVER STILL SOME ACCUMULATIONS ARE
POSSIBLE.
MARINE...
RAPID DEEPENING LOW WILL RESULT IN BRISK NORTH AND THEN NORTHWEST
WINDS THIS AFTERNOON INTO EARLY THURSDAY. WITH THE LOW GOING FURTHER
EAST THE THREAT OF GALES IS DIMINISHING ON THE WEST SIDE OF LAKE
MICHIGAN SO CURRENT SMALL CRAFT ADVISORY SHOULD SUFFICE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO NOON CST THURSDAY
FOR LMZ643>646
&&
$$
UPDATE...DDV/MBK
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
THURSDAY THROUGH TUESDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
535 AM CST WED DEC 24 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CST WED DEC 24 2014
THE MAIN FOCUS FOR TODAY IS WITH THE CHANCES FOR SNOW/DRIZZLE.
CURRENTLY...A SHEARED OUT/POSITIVELY TILTED MID LEVEL CLOSED
TROUGH EXTENDS FROM THE UPPER MISSISSIPPI RIVER VALLEY ON DOWN TO
THE WESTERN GULF WITH THE SHEAR AXIS RIGHT OVER WEST CENTRAL
WISCONSIN/EASTERN IOWA. AT THE SURFACE...A LOW/TROUGH IS CENTERED
OVER SOUTHEAST WISCONSIN WITH NORTHWESTERLY FLOW RUNNING ACROSS
THE REGION ON THE BACK SIDE OF THIS SYSTEM. NOT MUCH IN THE WAY OF
COLD AIR BEHIND IT WITH 850MB TEMPERATURES AROUND -5C.
PRECIPITATION-WISE...DRIZZLE HAS DEVELOPED IN A BAND NORTHWEST OF
THE SURFACE LOW AND ALONG THE MID LEVEL SHEAR AXIS ALONG THE
TROUGH. 24.06Z RAP SOUNDINGS FROM ALONG THIS BAND SHOW THAT THERE
IS A LACK OF ICE ALOFT WITH SATURATED LOW LEVELS. THESE SOUNDINGS
SHOW SOME COOLING AROUND 700MB WHICH COULD PUSH THE SATURATED
LAYER DOWN INTO THE -8C RANGE AND PERHAPS CAUSE A CHANGE OVER TO
LIGHT SNOW. WITH FORCING WEAK...EXPECT THAT DRIZZLE WILL BE THE
MAIN PRECIPITATION TYPE WITH IMPACTS MINIMAL THANKS TO SURFACE
TEMPERATURES AT 32 TO 36F. THE 24.06Z HRRR/RAP TAKES THIS MAIN
BAND EASTWARD THROUGH THE MORNING AND DIMINISHING ALONG THE WAY.
AS THE TROUGH/LOW SHIFT OFF TO THE EAST TONIGHT...MID
LEVEL/SURFACE RIDGING WILL PUSH IN FROM THE WEST AND MAY OFFER A
BRIEF PERIOD WHERE SKIES CLEAR OUT LATE TONIGHT. HAVE PLAYED SKY
COVER ON THE PESSIMISTIC SIDE SINCE AS SOON AS THE LOW LEVEL
MOISTURE SHIFTS EAST...SOME HIGH LEVEL CLOUD COVER APPEARS TO MOVE
IN ACCORDING TO THE 24.00Z NAM/GFS. TEMPERATURES WILL NOT DIVE
MUCH TONIGHT WITH LOWS ONLY IN THE MID 20S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 326 AM CST WED DEC 24 2014
THE FOCUS THEN SHIFTS TO PRECIPITATION CHANCES WITH THE NEXT
SYSTEM TO MOVE IN ON THURSDAY INTO FRIDAY NIGHT. RETURN SOUTHERLY
LOW LEVEL FLOW WILL BRING WARMER AIR UP FROM THE SOUTHERN PLAINS.
THERE HAS BEEN A FAIRLY CONSISTENT MESSAGE FROM THE 24.00Z AND
PREVIOUS MODELS RUNS THAT SHOW A 900-800MB FRONTOGENETIC BAND
DEVELOPING THURSDAY AFTERNOON ACROSS CENTRAL MINNESOTA INTO
NORTHERN WISCONSIN. LOCALLY...24.00Z NAM/GFS ARE SHOWING SOME LOW
LEVEL SATURATION WITH THE WARM AIR ADVECTION TAKING PLACE THURSDAY
NIGHT. IF FORCING WAS A BIT STRONGER IN THE LOW LEVELS...THERE
WOULD BE THE POTENTIAL TO GET SOME DRIZZLE TO FORM BUT AT THE
MOMENT IT LOOKS TOO WEAK.
BROAD MID LEVEL TROUGHING WILL MOVE INTO THE REGION FRIDAY/FRIDAY
NIGHT AND BRING THE NEXT BEST CHANCE FOR SOME SNOW AS IT COMES
THROUGH. AS THE DEEPER LIFT COMES IN WITH A MID LEVEL SHORT WAVE
TROUGH TRACKING THROUGH IOWA...SNOW SHOULD DEVELOP IN A SOUTHWEST
TO NORTHEAST BAND. WITH QPF AMOUNTS AROUND A TENTH OF AN INCH OR
LESS...EXPECT THAT ANY ACCUMULATIONS WILL BE MINOR AT AN INCH OR
LESS.
THE PASSING OF THIS TROUGH WILL MARK A PERIOD OF COLDER AIR
ADVANCING INTO THE REGION FROM CANADA. A VERY CONSISTENT SIGNAL IN
THE 24.00Z GFS/ECMWF IS WITH ANOTHER WAVE OF COLDER AIR MOVING
DOWN FROM NORTHERN CANADA FOR THE MIDDLE PART OF NEXT WEEK WITH
850MB TEMPERATURES FORECAST TO DROP TO -20C OR LOWER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 535 AM CST WED DEC 24 2014
A LINGERING TROUGH OF LOW PRESSURE IS PRODUCING AREAS OF -SN/-DZ
THIS MORNING. LOOKING FOR THIS TO END AT KRST AROUND 16Z AND AROUND
18Z FOR KLSE. OTHERWISE...IFR CIGS TO CONTINUE AT KRST THROUGH THE
PERIOD WITH KLSE EXPECTED TO BE ON THE BORDERLINE OF MVFR/IFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DAS
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
158 PM EST WED DEC 24 2014
.UPDATE...
ISSUED AT 158 PM EST WED DEC 24 2014
THE COLD FRONT IS MOVING INTO OUR AREA...NOW LOCATED NEAR KEKQ AND
JUST WEST OF KLEX. TEMPERATURES HAVE SOARED INTO THE UPPER 60S OUT
AHEAD OF THE BOUNDARY...THANKS TO SOME HOLES IN THE PRECEDING MID AND
HIGH LEVEL CLOUD DECK. A NICE BAND OF SHOWERS HAVE CONTINUED TO
DEVELOP ALONG AND BEHIND THE COLD FRONT. HAVE TAKEN POPS UP TO
CATEGORICAL IN THE WEST...AND THEN ALLOWED FOR A GRADUAL DIMINISHMENT
AS THE LINE COMES EAST AS THE FRONT STARTS TO SHEAR OUT WITH TIME.
UPDATES HAVE BEEN SENT.
UPDATE ISSUED AT 1103 AM EST WED DEC 24 2014
THE COLD FRONT IS CURRENTLY ALIGNED FROM IN/OH BORDER DOWN THROUGH
NEAR CENTRAL KENTUCKY...HAVING JUST PASSED THROUGH BWG...BUT STILL
SLIGHTLY WEST OF SDF. PLENTY OF SHOWER ACTIVITY IS FILLING IN ALONG
AND BEHIND THE FRONT...AND HAVE BEEFED UP POPS TO LIKELY FOR MOST AS
IT MAKES IT WAY TOWARDS EASTERN KENTUCKY THIS AFTERNOON. ALSO ADDED A
FEW MORE COUNTIES TO THE WIND ADVISORY...MAINLY HIGHLIGHTING
ELEVATIONS ABOVE 1500 FEET...CLOSER TO THE STRONGER WINDS OCCURRING
ALOFT. SPC STILL HIGHLIGHTS A MARGINAL THREAT OF STRONGER WIND GUSTS
ASSOCIATED WITH MORE INTENSE SHOWERS OR ISOLATED THUNDERSTORMS...SO
WILL CONTINUE TO ADVERTISE THIS POSSIBILITY ACROSS MUCH OF THE AREA
AS WELL IN THE HWO. UPDATES HAVE BEEN SENT.
UPDATE ISSUED AT 648 AM EST WED DEC 24 2014
UPDATED TO LOWER POPS THIS MORNING AS SOUTHEAST FLOW CONTINUES TO
STRENGTHEN WITH CLOUD HEIGHTS CONTINUING TO GO UP. THEY ARE NOW OVER
10KFT. THUS...CHANCES FOR MEASURABLE RAIN ARE DECREASING THROUGH THE
MORNING HOURS. BEST CHANCE OF RAIN STILL LOOKS TO COME WITH THE COLD
FRONT AS IT CROSSES THE AREA THIS AFTERNOON. LATEST HI-RES MODELS
CONTINUE TO SHOW THE POSSIBILITY OF A FEW THUNDERSTORMS AS THE FRONT
PUSHES ACROSS OUR AREA. SHOULD WARM UP NICELY GIVEN THE SOUTHEAST
FLOW AND LIMITED LOW CEILINGS THIS MORNING. WOULDN`T BE SURPRISED TO
SEE US GET EVEN WARMER THAN THE FORECAST CURRENTLY REFLECTS.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 316 AM EST WED DEC 24 2014
AREA OF LOW PRESSURE IS NOW STARTING TO MAKE ITS MOVE NORTH ACROSS
CENTRAL KENTUCKY...AND WILL END UP OVER SOUTHEAST MICHIGAN BY THIS
EVENING. STRONG LIFT ASSOCIATED WITH THE LOW PRESSURE SYSTEM WILL
SPREAD ACROSS THE AREA THROUGH DAYBREAK WITH RAIN BECOMING WIDESPREAD
ONCE AGAIN AFTER A BRIEF LULL OVER THE PAST FEW HOURS. HRRR AND RAP
ARE IN GOOD AGREEMENT THAT THIS LIFT WILL EXIT TO THE NORTH BY 9 OR
10 AM...WITH ANOTHER LULL IN PRECIPITATION EXPECTED THROUGH MIDDAY.
WITH THE MIDDAY LULL IN PRECIPITATION...HIGHS WILL WARM INTO THE 60S
FOR ONE MORE DAY.
FINALLY AS THE LOW SHIFTS NORTH THOUGH...A STRONG COLD FRONT WILL
PUSH EAST ACROSS THE AREA THIS AFTERNOON. WITH THE MILD
TEMPERATURES...WE MAY GENERATE SOME WEAK INSTABILITY TO SUPPORT
CONVECTIVE SHOWERS DEVELOPING ALONG THE FRONT AS IT PUSHES ACROSS THE
AREA. WHILE THUNDER CHANCES REMAIN LOW...CANNOT RULE OUT SOME THUNDER
WITH THE STRONGER CELLS...ESPECIALLY ACROSS NORTHERN KENTUCKY. GIVEN
THE ABUNDANCE OF MID LEVEL DRY AIR...AND STRONG 850MB WINDS AROUND 45
KNOTS...WE COULD SEE THE POTENTIAL FOR SOME HIGHER WINDS TO GET MIXED
DOWN WITH THE SHOWERS. HOWEVER...EVEN WITHOUT THE CONVECTIVE SUPPORT
FOR WINDS...THE SYNOPTIC SETUP BEHIND THE FRONT SHOULD SUPPORT 40+
MPH WINDS...ESPECIALLY ACROSS THE NORTHERN HALF OF THE AREA.
THUS...WILL GO AHEAD WITH A WIND ADVISORY FOR THE NORTHERN HALF OF
THE AREA. CONDITIONS ARE MORE MARGINAL FARTHER SOUTH...BUT A WIND
ADVISORY FOR THE HIGH TERRAIN NEAR THE VIRGINIA BORDER ALSO SEEMS IN
ORDER GIVEN THE STRONG WINDS AT 850MB. BEST THREAT FOR THE HIGHER
WINDS WILL BE AFTER 17Z AND BEFORE 03Z TONIGHT.
CONDITIONS WILL QUITE DOWN SOME THIS EVENING AS SUBSIDENCE SPREADS IN
BEHIND THE DEPARTING FRONT. HOWEVER...A SHORTWAVE TROUGH WILL PUSH
EAST ACROSS THE AREA LATE TONIGHT...WITH THE MOISTURE DEPTH
INCREASING TO SUPPORT SOME LIGHT RAIN/DRIZZLE. COLDER AIR WILL ALSO
BE SPILLING INTO THE AREA TONIGHT BEHIND THE FRONT. WHILE MOST AREAS
WILL STAY MILD ENOUGH FOR JUST RAIN...THE HIGHER TERRAIN IN THE
SOUTHEAST WILL SUPPORT SOME SNOW CHANCES. IN FACT...CONDITIONS ALIGN
GOOD ENOUGH TONIGHT WE COULD SEE A LIGHT COATING OF SNOW ON THE HIGH
TERRAIN ABOVE 2500 FEET LATE TONIGHT.
HEIGHTS WILL BE QUICK TO BUILD BACK ACROSS THE AREA ON CHRISTMAS.
CLOUDS MAY BE STUBBORN THROUGH THE FIRST HALF OF THE DAY...BUT WE
SHOULD DEFINITELY SEE A DECREASING TREND THROUGH THE AFTERNOON AND
EVENING AS THE RIDGE CENTERS ITSELF OVER THE REGION. HIGHS WILL
STRUGGLE TO WARM GIVEN THE ABUNDANCE OF CLOUDS THROUGH THE FIRST HALF
OF THE DAY...SO PLAN TO KEEP HIGHS LIMITED TO THE LOW TO MID 40S WITH
30S ON THE HIGHER TERRAIN IN THE SOUTHEAST.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 420 AM EST WED DEC 24 2014
THE PERIOD IS EXPECTED TO BEGIN WITH A CLOSED UPPER LOW CONTINUING TO
DEPART TO THE NORTHEAST OF THE REGION WITH UPPER LEVEL RIDGING
BUILDING ACROSS THE AREA AT THE START OF THE PERIOD. FURTHER TO THE
WEST A TROUGH IS EXPECTED TO EXTEND FROM THE NORTHERN PLAINS SOUTH
INTO THE SOUTHERN ROCKIES AND NORTHERN MEXICO. SFC AND UPPER LEVEL
RIDGING WILL GRADUALLY WORK ACROSS THE AREA FOR THU NIGHT INTO FRIDAY
AND THEN DEPART TO THE EAST FRIDAY NIGHT INTO SATURDAY. MEANWHILE A
SHORTWAVE TROUGH IS ANTICIPATED TO EJECT FROM THE WESTERN TROUGH
ACROSS THE PLAINS TOWARD THE GREAT LAKES FROM FRIDAY INTO SATURDAY.
THIS WILL LEAD TO GRADUALLY LOWERING HEIGHTS ACROSS THE GREAT LAKES
AND OH VALLEY AND A COLD FRONT DROPPING TOWARD THE REGION TO START
THE WEEKEND. THIS SHOULD BEGIN THE START OF AN UNSETTLED PERIOD.
OVER TIME...A RATHER BROAD TROUGH IS EXPECTED TO DEVELOP FROM CENTRAL
CANADA SOUTH INTO THE ROCKIES AND THEN EAST INTO THE EASTERN CONUS.
MODELS VARY FROM RUN TO RUN AND MODEL TO MODEL WITH THE HANDLING OF
INDIVIDUAL SHORTWAVES IN WEST SOUTH TO SOUTHWEST FLOW DURING THIS
PERIOD AND THE INTERACTION WITH A BAROCLINIC ZONE...THE FRONT THAT
MOVES INTO THE AREA EARLY IN THE WEEKEND...RESULTING IN SFC WAVES
DEVELOPING ALONG THE FRONT. THE ECMWF IS GENERALLY SLOWER BRINGING
THIS FRONT ACROSS THE AREA AND IS ALSO STRONGER AND FURTHER SOUTHEAST
WITH A SFC WAVE SUN NIGHT INTO MONDAY. AS THIS LAST SYSTEM DEPARTS AN
ARCTIC BOUNDARY SHOULD APPROACH THE AREA TUE OR WED.
DUE TO AN OVERALL LACK OF COLDER AIR FOR MOST OF THE PERIOD...MUCH OF
THE PRECIPITATION SHOULD FALL AS RAIN...ALTHOUGH SOME SNOW MAY MIX IN
ON SUNDAY NIGHT INTO EARLY ON MONDAY IN THE HIGHEST TERRAIN AND NORTH
OF THE MTN PARKWAY. A MIX OF RAIN AND SNOW WILL REMAIN POSSIBLE INTO
THE DAY ON TUESDAY AS WE HELD ONTO SLIGHT CHANCE POPS TO ACCOUNT FOR
THE ECMWF RUN. BOTH THE GFS AND ECMWF RUNS SUPPORT A WET END TO THE
WEEKEND.
AS FOR TEMPERATURES...THE PATTERN FAVORS A RIDGE VALLEY TEMPERATURE
SPLIT ON THU NIGHT AS SKIES WILL HAVE CLEARED OR SHOULD BE CLEARING
AS SFC AND UPPER LEVEL RIDGING WORK INTO THE AREA. A RELATIVELY DRY
AIR MASS AND A DOWNSLOPE COMPONENT SHOULD LEAD TO A RATHER MILD DAY
ON FRIDAY...ESPECIALLY FOR VALLEYS NEAR THE VA BORDER. THE DEPARTING
RIDGE SHOULD AGAIN FAVOR MILDER LOWS ON FRI NIGHT...BUT YET ANOTHER
RIDGE/VALLEY SPLIT. SATURDAY SHOULD AGAIN BE MILD AHEAD OF THE
BOUNDARY. WITH THE BAROCLINIC ZONE OVER OR NEAR THE REGION A
GENERALLY NW TO SOUTH OR SOUTHEAST GRADIENT IN TEMPERATURES IS
ANTICIPATED FOR THE REMAINDER OF THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 158 PM EST WED DEC 24 2014
VFR CONDITIONS OUT AHEAD OF THE COLD FRONT WILL QUICKLY CRASH TO MVFR
AND EVENTUALLY IFR FROM WEST TO EAST THROUGH THE REST OF THIS
AFTERNOON...WITH A 2-3 HOUR PERIOD OF SHOWERS. SUSTAINED SOUTH TO
SOUTHWEST WINDS OF 10 TO 15 KTS...WITH GUSTS UP TO 25 KTS...WILL TURN
TO THE WEST AT 10 TO 25 KTS...WITH GUSTS IN THE 25 TO KTS RANGE.
THESE HIGHER WINDS WILL LAST AN HOUR OR SO BEFORE THE GUSTS SETTLE
BACK DOWN TO AROUND 20 KTS THROUGH THIS EVENING. ONCE THE FRONTAL
SHOWERS EXIT OFF TO THE EAST THIS EVENING...SOME LIGHTER PRECIPTATION
WILL BE POSSIBLE OVERNIGHT. WSW WINDS WILL DIMINISH TOWARDS
DAWN...WITH IFR CEILINGS LIKELY IMPROVING TOWARDS MVFR AS WELL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR KYZ044-050>052-
058>060-068-069-088-104-106>120.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...KAS
LONG TERM...JP
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
259 PM EST WED DEC 24 2014
.SYNOPSIS...
STRONG LOW PRESSURE AND ITS ASSOCIATED COLD FRONT WILL CROSS THE
REGION TODAY INTO TONIGHT BRINGING SHOWERS...A FEW THUNDERSTORMS...
AND STRONG WINDS THIS EVENING.
&&
.NEAR TERM /THROUGH TONIGHT/...
EARLIER REMOVAL OF POPS DUE TO LACK OF FORCING WITHIN THE QUASI-WARM
SECTOR (EXCEPT FOR THE PA/WV/MD RIDGES) HAS PLAYED OUT WELL WITH
NOTHING MORE THAN A FEW SPITS. THIS TREND SHOULD CONTINUE FOR THE
NEXT SEVERAL HOURS WITH JUST A FEW BRIEF SHOWERS ACROSS MOST OF THE
CWA...AND STEADIER RAINS ACROSS THE LAUREL HIGHLANDS AND POINTS
SOUTH.
MEANWHILE...A DEEPENING AND INCREASINGLY NEGATIVE TILT MID LEVEL
TROUGH WAS BEGINNING TO ACCELERATE NORTHEAST THROUGH ILLINOIS THIS
AFTERNOON. LARGE SCALE ASCENT...ASSOCIATED WITH STRONG MID LEVEL
HEIGHT FALLS...WAS BEGINNING TO OVERTAKE THE WARM SECTOR...AND
CONFIRMED BY VISIBLE SATELLITE IMAGERY WITH A RECENT INCREASE IN
SW-NE ORIENTED LOW-TOPPED CONVECTIVE BANDS. THIS FORCED ASCENT IS
OCCURRING WEST OF THE PRONOUNCED MID-HIGH LEVEL MOIST PLUME WHICH
HAS ENVELOPED THE REGION...AND THUS ITS EVOLUTION OVER THE NEXT
SEVERAL HOURS IS AN INTERESTING FORECAST CHALLENGE.
DYNAMICALLY FORCED CONVECTION...MOST OF WHICH WILL BE ALONG AND POST
SFC FRONTAL...WILL REACH THE WESTERN CWA AROUND 22Z AND EXIT THE
EASTERN RIDGES AROUND 05Z. AN AXIS OF MODEST INSTABILITY...ON THE
ORDER OF 100-200 J/KG MUCAPE...WILL GRADUALLY SHIFT NORTHEAST ACROSS
THE ENTIRE CWA THIS EVENING...EVEN WITH THE LOSS OF DAYLIGHT. IN
FACT...AREAS OF NW PA AND THE LAUREL HIGHLANDS...WHICH HAVE BEEN
EITHER NORTH OF THE WARM FRONT OR EAST OF THE DAMMING WEDGE
FRONT...WILL LIKELY SEE A SPIKE IN TEMPERATURES/DEWPOINTS EARLY THIS
EVENING AS A PRE-FRONTAL TROUGH EFFECTIVELY SCOURS THE AREA AND
SHIFTS WINDS INTO THE SOUTHWEST. PRECIPITATION LOOKS TO BE NEARLY
CERTAIN...SO THE QUESTION PRIMARILY FOCUSES ON THUNDER
CHANCES. GIVEN THE MID LEVEL SUBSIDENCE WITHIN THE SYNOPTIC DRY
SLOT...SURFACE BASED CONVECTIVE CLOUD TOPS WILL LIKELY BE LIMITED TO
AROUND 16-18KFT PER SOUNDING ANALYSIS...MAKING LIGHTNING GENERATION
DIFFICULT BUT CERTAINLY NOT IMPOSSIBLE. HAVE RETAINED "ISOLATED
THUNDER" WORDING FOR EARLY THIS EVENING.
REGARDING THE WIND ADVISORY...THE WINDOW FOR STRONG GUSTS IS MUCH
SMALLER THAN THE EXISTING ADVISORY WOULD SUGGEST...OWING TO A
NATURALLY POOR THERMAL CONTRAST ASSOCIATED WITH PROGRESSIVE NEGATIVE
TILT TROUGHS. IN THE ABSENCE OF STRONG COLD ADVECTION AND A SIZABLE
POST-FRONTAL SURFACE HIGH...THE STRONG LOW LEVEL PRESSURE GRADIENT
WILL BE CO-LOCATED BENEATH THE MID LEVEL JET AXIS...WHICH ITSELF
WILL MOVE SWIFTLY THROUGH THE AREA. THIS LIMITS THE WINDOW OF
OPPORTUNITY FOR STRONG WIND GUSTS TO FRONTAL CONVECTION AND ONLY A
FEW HOURS BEHIND THE FRONT. THE EXCEPTION WILL BE OVER THE SOUTHEAST
RIDGES WHERE THE EFFECTS OF STRONGER WINDS ALOFT WILL LINGER
OVERNIGHT. DOWNWARD MOMENTUM TRANSPORT FROM PRECIPITATION WILL
LIKELY YIELD MOST OF THE STRONGER GUSTS...NORTHEAST CELL MOVEMENT
(PARALLEL TO MID LEVEL FLOW VECTORS) WOULD SUGGEST THAT STRONGER
CONVECTIVE CELLS COULD YIELD SOME RATHER IMPRESSIVE GUSTS. GIVEN THE
STRONG LINEAR FORCING UNDERWAY...WOULD NOT BE SURPRISED TO SEE A
NARROW COLD-FRONTAL SQUALL LINE DEVELOP OVER OHIO/KENTUCKY OVER THE
NEXT SEVERAL HOURS. DESPITE THE SPARSE LIGHTNING YIELD EXPECTED...
ANY SHORT-FUSE THREAT FOR DAMAGING WINDS WOULD BE HANDLED BY SEVERE
THUNDERSTORM WARNINGS.
WIND ADVISORY IS IN THE PROCESS OF BEING MODIFIED AS FOLLOWS:
OH/WV PANHANDLE: 22-04Z
PA/WV (EXCEPT THE RIDGES): 00Z-06Z
PA/WV/MD RIDGES: 03Z-09Z
OTHERWISE...LARGE SCALE ASCENT ENDS QUICKLY FROM WEST TO EAST AFTER
06Z...AND ALTHOUGH A CHANGE-OVER FROM RAIN TO SNOW IS
DEPICTED...ONLY FLURRIES OR EVEN DRIZZLE ARE ANTICIPATED.
BOOKBINDER
&&
.SHORT TERM /CHRISTMAS DAY INTO CHRISTMAS NIGHT/...
SOUTHWEST WINDS WILL DIMINISH QUICKLY TOMORROW MORNING...AND A
ONE-SHOT DAY OF COLD AIR WILL ARRIVE WITH TEMPERATURES STRUGGLING TO
GET BACK TO 40 DEGREES UNDER CLOUD SKIES. ENOUGH RESIDUAL LIFT
AROUND THE DEPARTING CYCLONE WILL PERSIST IN THE MORNING TO GENERATE
SOME SCATTERED SNOW SHOWERS...ALTHOUGH THE MOISTURE DEPTH IS SO
SHALLOW THAT IT MAY AGAIN BE MORE OF A DRIZZLE/SNIZZLE. DO NOT
ANTICIPATE MORE THAN A LIGHT DUSTING UP TOWARD/NORTH OF I-80. ACROSS
THE RIDGES...A STRONGER UPSLOPE WIND COMPONENT IS DEPICTED BY THE
MODELS SO PERHAPS A SPARSE INCH COULD FALL ACROSS THE MD/WV RIDGES.
BOOKBINDER
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS IS TYPICAL WITH PROGRESSIVE NEGATIVE TILT TROUGHS...THE BRIEF
SHOT OF COLD AIR WILL DEPART AS THE SYSTEM LIFTS INTO THE CANADIAN
MARITIMES...ALLOWING FOR A TEMPORARY RETURN TO ZONAL AND/OR DAMPENED
MID LEVEL RIDGING OVER THE EASTERN CONUS FRIDAY AND
SATURDAY...FEATURING MUCH ABOVE NORMAL TEMPERATURES.
A PROGRESSIVE WAVE WILL SETTLE ACROSS THE AREA SATURDAY NIGHT AND
EARLY SUNDAY BRINGING A CHANCE FOR PRECIPITATION...AND BETTER ACCESS
TO MORE SEASONABLY COLD AIR IN ITS WAKE.
BOOKBINDER
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
WITH THE FORECAST AREA STILL MOSTLY IN THE WARM SECTOR...VFR
CONDITIONS TO START FOR MOST TERMINALS. WITH THE EASTERN RIDGES ON
THE FRINGE OF CONTINUED DAMMING...LOWER CLOUDS AND EVEN SOME FOG
LINGER THERE. LLWS GROUPS INCLUDED AS SSW WINDS OF 40-50 LIE JUST
A COUPLE THOUSAND FEET OFF THE SURFACE.
WELL-ADVERTISED COLD FRONT WILL PUSH THROUGH DURING THE EVENING
HOURS BETWEEN 22Z AND 04Z. BAND OF LOW-TOPPED CONVECTION STILL
BEING FORECAST BY HRRR AND OTHER MODELS AND HAVE HANDLED THIS WITH
TWO HOUR TEMPO GROUPS IN EACH TAF. CIGS WILL DROP BACK TO MVFR AS
THE FRONT APPROACHES AND PASSES. MAIN ISSUE WILL BE THE
WIND...WITH S/SW GUSTS TO 40-45 KNOTS POSSIBLE WITH
CONVECTION..AND IMMEDIATELY FOLLOWING FROPA. WINDS WILL SLOWLY
DIMINISH WITH TIME OVERNIGHT BUT STILL EXPECT AT LEAST 20-30 KNOT
GUSTS THROUGH THE REMAINDER OF THE TAF PERIOD. MVFR CIGS WILL
CONTINUE...PERHAPS LOWERING TO IFR BY 12Z CLOSER TO LAKE ERIE.
LINGERING PRECIP WILL CHANGE OVER TO SNOW SHOWERS BY 12Z
AREAWIDE...BUT SIGNIFICANT RESTRICTIONS FROM SNOW ARE NOT FORECAST.
OUTLOOK.../WEDNESDAY NIGHT THROUGH MONDAY/...
CIG/VIS RESTRICTIONS THROUGH THURSDAY WILL IMPROVE TO VFR FRIDAY
AND CONTINUE UNTIL ANOTHER FRONTAL SYSTEM CROSSES THE REGION
SATURDAY AFTERNOON.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND ADVISORY FROM 9 PM THIS EVENING TO 4 AM EST THURSDAY
FOR MDZ001.
OH...WIND ADVISORY UNTIL 11 PM EST THIS EVENING FOR OHZ039>041-
048>050-057>059-068-069.
PA...WIND ADVISORY FROM 7 PM THIS EVENING TO 1 AM EST THURSDAY FOR
PAZ007>009-013>016-020>023-029-031-073-075.
WIND ADVISORY FROM 9 PM THIS EVENING TO 4 AM EST THURSDAY FOR
PAZ074-076.
WV...WIND ADVISORY UNTIL 11 PM EST THIS EVENING FOR WVZ001>004-012.
WIND ADVISORY FROM 7 PM THIS EVENING TO 1 AM EST THURSDAY FOR
WVZ021-022.
WIND ADVISORY FROM 9 PM THIS EVENING TO 4 AM EST THURSDAY FOR
WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
223 PM EST WED DEC 24 2014
.SYNOPSIS...
LOW PRESSURE STRENGTHENS WEST OF THE MOUNTAINS TODAY...AND . AN
ASSOCIATED COLD FRONT WILL CROSS THE AREA TONIGHT. HIGH PRESSURE
BUILDS BACK IN FROM THE SOUTHWEST CHRISTMAS DAY THROUGH FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST WX ANALYSIS CONTINUES TO FEATURE A DYNAMIC SYSTEM
TAKING SHAPE OVER THE DEEP SOUTH INTO THE TENNESSEE VALLEY AT
MIDDAY. LOCALLY...A RESIDUAL COOL-WEDGE AIRMASS IS HANGING TOUGH
ACROSS THE PIEDMONT, KEEPING TEMPS IN THE MID/UPPER 40S TO LOW 50S
ALONG AND W OF THE RIC METRO AREA. MEANWHILE, SFC WARM/COASTAL
FRONT IS MOVING ONSHORE WITH TEMPERATURES NOW WELL INTO THE
60S OVER SE VA & NE NC. WV SAT IMAGERY SHOWING BROAD SWATH OF WARM
CONVEYOR BELT MOISTURE LIFTING NORTH FROM THE EAST CENTRAL GULF
COAST ACROSS THE LOCAL AREA.
SFC LOW OVER THE SE CONUS WILL DEEPEN AND TRACK NNE INTO THE OHIO
VALLEY THROUGH THIS EVENING. BROAD SWATH OF MOISTURE WILL LIFT ENE
ACROSS THE REGION THROUGH THE BALANCE OF THE DAY, WITH PERIODIC
SHOWERS CONTINUING OVER THE PIEDMONT. THE NEW NAM/ARW IS A BIT
CLOSER IN HRRR DEPICTION OF BRIEF LULL IN PCPN BY LATE AFTN ON
INTO THE EARLY EVENING AS MID-LEVEL DRY SLOT, CURRENTLY LIFTING
ACROSS THE MID SOUTH INTO THE WESTERN CAROLINAS, SWINGS ACROSS
THE REGION. HOWEVER, PLENTY OF LLVL MOISTURE TO KEEP OVC WORDING
THROUGHOUT.
REGARDING CONVECTIVE POTENTIAL, HAVE CONFINED THUNDER WORDING TO
THE SE COASTAL PLAIN AFTER 20Z AS TEMPERATURES AND DEWPOINTS
CONTINUE TO RISE. SPC HAS ADDED THE SE IN A SLIGHT SEVERE RISK FOR
TONIGHT IN THE PRESENCE OF A WARM AND MOISTURE RICH AIRMASS AND A
STRONG 925-700MB WIND FIELD. DESPITE MEAGER SFC BASED INSTABILITY
WITH LACK OF CLOUD COVER, MID LVL SHEAR/HELICITY PARAMETERS WOULD
ARGUE FOR A CONTINUED THUNDER MENTION OVER THE COASTAL AREAS.
THUS, WL RETAIN SLIGHT CHC T OVER THE COASTAL PLAIN, MAINLY FOR
THE LATE AFTN AND EVENING HOURS.
THE COLD FRONT ARRIVES FROM THE W LATE THIS EVENING AND MOVES W-E
ACROSS THE AREA BETWEEN 03-06Z TONIGHT. DROPPED POPS OFF DURING
AFOREMENTIONED LULL PERIOD EARLY THIS EVENING, WITH MORE SCATTERED
RAIN SHRAS TO PERSIST LATER IN THE EVENING AND AFTER
MIDNIGHT...RAPIDLY DIMINISHING BEHIND THE FRONT AFTER 06Z TOWARDS
DAWN CHRISTMAS MORNING.
BY LATE AFTERNOON, EXPECT TEMPS TO RANGE FROM THE LOW TO MID 50S
WELL INLAND...MID/UPPER 60S FOR CENTRAL PORTIONS TO AROUND 70 SE.
THESE HIGHS WILL BE NEAR DAILY RECORDS...SEE THE CLIMATE SECTION
BELOW FOR DETAILS. GIVEN ONLY WEAK CAA, EXPECT TEMPS TO BE SLOW TO
DROP OFF OVERNIGHT, LIKELY LINGERING IN THE 50S AND 60S FOR MUCH
OF THE NIGHT.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
DRIER AIR ARRIVES CHRISTMAS MORNING AS HIGH PRESSURE BUILDS IN FROM
THE W. A SLOWER FRONTAL PASSAGE WILL RESULT IN A MILD CHRISTMAS
MORNING WITH LOWS RANGING FROM THE MID 40S FAR W...TO THE MID/UPPER
50S SE. THE SKY SHOULD BECOME MAINLY SUNNY WITH SCT AFTERNOON CU
ALONG WITH BREEZY WESTERLY FLOW BY MID/LATE MORNING CHRISTMAS DAY.
HIGHS SHOULD RANGE FROM THE MID 50S TO LOWER 60S CHRISTMAS DAY AS
CAA IS WEAK AND WILL BE OFFSET BY DOWNSLOPE WARMING (AND DUE TO A
WARM BEGINNING).
CLEAR/SEASONABLE THURSDAY NIGHT WITH LOWS IN THE UPPER 20S TO MID
30S. SURFACE HIGH PRESSURE SETTLES IMMEDIATELY OFF THE COAST FRIDAY
RESULTING IN LIMITED MIXING/LIGHT WINDS AND SUNNY CONDITIONS. HIGHS
SHOULD GENERALLY BE IN THE 50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE MODELS ARE IN GOOD AGREEMENT TO BEGIN THE PERIOD FRIDAY NIGHT
WITH THE STRONG RIDGING OVER THE SOUTHEASTERN US AND HIGH PRESSURE
OVER THE SOUTHEAST...CENTERED OVER EASTERN VA/NC. BUT THE MODELS
STRUGGLE WITH THE BREAKING DOWN OF THE RIDGE WITH THE GFS BREAKING
IT DOWN MUCH MORE QUICKLY THAN THE ECMWF. THE GFS ALLOW THE NEXT
COLD FRONT TO DROP INTO THE ARE SAT NIGHT AND MOVES IT SOUTH OF
THE REGION BY SUNDAY MORNING...SETTING UP AN OVERRUNNING PATTERN
SUNDAY AFTERNOON INTO MONDAY MORNING. THE ECMWF...AND THE 12Z IS
FURTHER NORTH WITH FEATURES THAN 00Z RUN...KEEPS THE RIDGE MUCH
STRONGER OVER THE SE AND DOES NOT ALLOW THE COLD FRONT TO MOVE
THROUGH THE AREA SAT NIGHT. IT STALLS THE FRONT OVER THE AREA ON
SUNDAY AND AS A WAVE OF LOW PRESSURE FORMS ALONG THE BOUNDARY AND
LIFTS NE INTO THE CENTRAL APPALACHIANS...IT PUSHES GULF MOISTURE
INTO THE AREA. THE 00Z ECMWF PUSHED THE WAVE OFF THE COAST BY
MONDAY...BUT THE 12Z RUN LIFTS THE LOW TO THE NORTH AND DRAGS A
COLD FRONT ACROSS THE REGION ON TUESDAY.
SO FOR NOW WITH THE GREAT SPREAD IN THE MODELS...HAVE TRENDED
TOWARD HPC/WPC GUIDANCE...WHICH IS SIMILAR TO THE 00Z ECMWF AND
BROUGHT THE WAVE INTO THE REGION ON SUNDAY AFTERNOON AND EVENING
WITH IT EXITING BY MONDAY AFTERNOON. HAVE INCREASED POPS TO 50%
FOR THAT PERIOD...KEEPING SATURDAY DRY. HAVE ALSO GONE DRY ON
MONDAY NIGHT INTO TUESDAY. THE BIG DIFFERENCE COMES TO
TEMPERATURES AS THE GFS WOULD ALLOW MUCH COLD AIR INTO THE REGION
BEGINNING ON SUNDAY THROUGH TUESDAY. THIS COULD ALSO POTENTIALLY
LEAD TO SOME WINTRY PCPN WITH WAVE ON SUNDAY NIGHT. FOR NOW HAVE
KEPT TEMPERATURES ABOVE FREEZING AND ALL RAIN WITH THE COLD AIR
BEING KEPT MORE TO THE NORTH. FOR TEMPERATURES HAVE ALLOW FOR A
GRADUAL COOL DOWN THROUGH THE PERIOD WITH THE COLDEST AIR ARRIVING
ON TUESDAY WITH HIGHS IN THE 40S.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
COMPLEX WEATHER SYSTEM ACROSS THE REGION THIS AFTERNOON AS WARM FRONTAL
BOUNDARY AS MOVED INTO THE AREA FROM THE EAST...STRETCHING FROM
NEAR DOV SW TO JUST NORTH OF XSA TO NEAR RIC AND THEN SW TO RDU.
EAST OF THE FRONT...THE WINDS HAVE TURNED SOUTHERLY AND THE
CEILINGS ARE BOUNCING FROM LIFR IN SHOWERS TO VFR WITH
VISIBILITIES ONLY BEING REDUCED IN THE SHOWERS. WEST OF THE
FRONT...THE LOW LIFR CLOUDS AND IFR TO LIFR VISIBILITIES LINGER.
THE FRONT.
THE LOW PRESSURE SYSTEM ASSOCIATED WITH THE FRONT WILL LIFT FROM
THE OHIO VALLEY NORTHEASTWARD INTO SERN CANADA AND PULL AN
ASSOCIATED COLD FRONT ACROSS THE REGION. THE WEDGE OF COOLER AIR
THAT IS WEST OF THE WARM FRONT AT THIS TIME WILL BE HARD TO
DISLODGE...BUT EVENTUALLY EXPECT THIS TO BREAK AND ALLOW CEILINGS
TO LIFT. SO FOR RIC DO SHOW SOME CEILING IMPROVEMENT LATER THIS
AFTERNOON AND EARLY THIS EVENING. THE REST OF THE SITES ARE ALL
EAST OF THE FRONT AND WHILE SOME IFR CEILINGS ARE STILL
AROUND...THE MAJORITY OF THE CEILINGS ARE MVFR OR HIGHER WITH THE
WIND BLOWING 10 TO 15 KT WITH HIGHER GUST.
THE COLD FRONT WILL ARRIVE THIS EVENING BETWEEN 3Z AND 9Z. AHEAD
OF THE FRONT ANOTHER LINE OF SHOWERS IS EXPECTED...ALTHOUGH WITH
THE DEEPER MOISTURE EAST OF THE AREA BY THEN IT MAY BE A SMALLER
NARROWER LINE. CURRENTLY ALLOWED FOR ABOUT 3 - 4 HOUR WINDOW OF
MVFR CONDITIONS WITH THE SHOWERS BUT IT MAY BE LESS THAN THAT.
BEHIND THE FRONT...THE AIR DRIES QUICKLY WITH VFR CONDITIONS
RETURNING BY 12Z FOR MOST AREAS.
OUTLOOK...HIGH PRESSURE DOMINATES THURSDAY AFTERNOON THROUGH
SATURDAY WITH DRY WEATHER. A CHC FOR RAIN RETURNS SUNDAY AS LOW
PRESSURE APPROACHES FROM THE WEST.
&&
.MARINE...
WINDS HAVE INCREASED TO 15 TO 20 KT OVER THE WATERS WITH THE WARM
FRONT LIFTING NORTH OF THE AREA. AS A RESULT...THE FOG THAT HAD
BEEN PLAGUING THE REGION HAS LIFTED AND THE ADVISORY HAS BEEN
CANCELLED.
PREV DISCUSSION....
DENSE FOG ADVISORY IS IN EFFECT FOR THE MARINE AREA THROUGH LATE
THIS AFTERNOON AS WARM MOIST AIR MOVES OVER THE RELATIVELY COOL
WATERS.
AS OF 11Z...WINDS WERE BEGINNING TO INCREASE FROM THE SE. SCA
STARTED AT 15Z FOR THE MOUTH OF THE BAY AS WAVES WILL SOON REACH 4
FT IN THE CHANNEL.
PREVIOUS DISCUSSION...
AS OF 08Z...WINDS REMAIN LIGHT OVER THE MARINE AREA BUT ARE FORECAST
TO INCREASE FROM THE SE AND THEN S THIS MORNING AS A WARM FRONT
MOVES N THROUGH THE WATERS AND LOW PRESSURE DEEPENS OVER THE OHIO
VALLEY. SCA IS IN EFFECT FOR ALL THE WATERS EXCEPT THE RIVERS SAVE
THE LOWER JAMES. SCA CONDITIONS OVER INLAND WATERS MAY BE MINIMAL
AT FIRST DUE TO LIMITED MIXING BUT WILL BECOME MORE FAVORABLE
THURSDAY MORNING. HAVE ADDED THE LOWER JAMES WITH TIMES STAGGERED
SLIGHTLY FROM THE BAY (STARTING AT 21Z TODAY AND ENDING 3 HOURS
EARLIER THURSDAY). LATER SHIFTS MAY NEED TO CONSIDER SCA BEHIND
THE COLD FRONT FOR OTHER RIVER ZONES ON THURSDAY MORNING.
SCA IS ALREADY IN EFFECT N OF PARRAMORE ISLAND. SEAS ARE EXPECTED TO
BUILD TO 5 FT OR HIGHER BY 18Z S OF THERE AND DECIDED TO BEGIN SCA S
OF PARRAMORE ISLAND AT 15Z TO ALLOW SUFFICIENT CUSHION.
HIGH PRESSURE THEN BUILDS INTO THE REGION ON THURSDAY NIGHT AND
LINGERS THROUGH SATURDAY AS A STRONG UPPER LEVEL RIDGE BUILDS INTO
THE SOUTHEASTERN US AND KEEPS STRONG HIGH PRESSURE AT THE SURFACE
OVER THE REGION THROUGH SATURDAY. LOW PRESSURE APPROACHES FROM THE
SW SUNDAY AND MOVES ACROSS THE REGION MONDAY. PRELIMINARY
INDICATIONS DO NOT INDICATE THAT A SCA WILL BE NEEDED WITH THIS
SYSTEM.
&&
.TIDES/COASTAL FLOODING...
WATER LEVELS AT BISHOPS HEAD AND CAMBRIDGE ARE EXPECTED TO
APPROACH MINOR FLOODING LATE TODAY AND EARLY THIS EVENING.
&&
.CLIMATE...
RECORD HIGHS FOR CHRISTMAS EVE/WED 12/24:
RICHMOND.......71 F (1988)
NORFOLK........75 F (1891)
SALISBURY......67 F (1990)
ELIZ CITY NC...75 F (1990)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...COASTAL FLOOD ADVISORY UNTIL 8 PM EST THIS EVENING FOR
MDZ021>023.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THURSDAY FOR ANZ630>634-
650-652-654-656-658.
SMALL CRAFT ADVISORY UNTIL 1 PM EST THURSDAY FOR ANZ638.
&&
$$
SYNOPSIS...AJZ/ALB
NEAR TERM...AJZ/MAM
SHORT TERM...AJZ/LKB
LONG TERM...ESS
AVIATION...ESS
MARINE...LSA/ESS
TIDES/COASTAL FLOODING...
CLIMATE...
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1246 PM EST WED DEC 24 2014
.SYNOPSIS...
STRONG LOW PRESSURE AND ITS ASSOCIATED COLD FRONT WILL CROSS THE
REGION TODAY INTO TONIGHT BRINGING SHOWERS AND STRONG WINDS.
&&
.NEAR TERM /THROUGH TONIGHT/...
NO CHANGES MADE THIS MORNING AS THE NEAR TERM LOOKS TO BE IN GOOD
SHAPE.
**NOTE** THERE WAS AN ERROR OVERNIGHT THAT RESULTED IN HIGH SNOW
AMOUNTS MAKING IT INTO THE FORECAST FOR TOMORROW MORNING. WE ARE
CURRENTLY WORKING ON THE ISSUE...BUT IN THE MEANTIME PLEASE
DISMISS HIGHER AMOUNTS. PREV DISCUSSION BELOW..
DEEPENING LOW PRES AND ITS ASSOCIATED CDFNT WL TRACK FM THE
OH VLY INTO THE GT LKS RGN TDA INTO TNGT. PERIODIC SHWRS WL CONT
TDA INTO TNGT AS MSTR STREAMS IN FM THE GULF IN SW FLOW AHD OF THE
ADVNG SYSTEM...AND AS FROPA OCCURS. AS COLD ADVCTN SETS UP A FEW
SNW SHWRS ARE PSBL OVRNGT. PROGRESSION AND A LACK OF SUSTAINED
CNVRGNC SHOULD LMT BASIN AVG RAIN TOTALS TO ARND A HALF INCH FOR
THE PD.
THE POTENTIAL FOR STRONG WINDS WITH PASSAGE OF...AND IMMEDIATELY
BEHIND THE CDFNT IS EXPD WED EVE INTO ERLY THU. IN ADDN...ELEVATED
INSTBY COULD RESULT IN A FEW TSTMS ALG THE CDFNT LT TDA AND THIS
EVE...SOME OF WHICH COULD MIX DOWN DAMAGING WNDS. THESE DAMAGING
WND GUSTS COULD BE HANDLED BY CNVCTV WRNGS IF THIS POTENTIAL
MATERIALIZES. UNTIL THEN...STRONG WARM ADVCTN WL CAP THE SFC
TDA...INHIBITING MIXING/GUSTS.
ISSUED A WND ADVY FOR GUSTS 45 TO 50 MPH ASSOCIATED WITH THE
SYNOPTIC PRES GRADIENT WNDS LT TDA INTO ERLY THU. THE ADVY MAY BE
AUGMENTED BY STORM PREDICTION CENTER PARTICIPATION IN A SHALLOW
CONVECTIVE EVENT AS MNTND ABV.
TEMPS ARE EXPD TO AVG ARND 20 TO 25 DEG ABV SEASONAL LVLS TDA.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
CONTD GUSTY WNDS ARE EXPD INTO ERLY THU ESP ESP ACRS WRN PA AND IN
THE RIDGES. WKNG PRES GRADIENT SHOULD ALLOW FOR DCRG WND GUSTS
THRU THE DAY. SNW SHWR CHCS ARE EXPD THU MRNG INTO ERLY AFTN WITH
AN ADVNG UPR TROF...THOUGH LACK OF DEEP MSTR AND MARGINAL TEMPS
SHOULD ALLOW FOR LTL IF ANY ACCUMS MAINLY N OF I 80 AND IN THE
RIDGES. BLDG HIGH PRES IS PROGGED TO BRING DRY WEA LTR THU INTO
FRI NGT. ANOTHER ADVNG GT LKS SHRTWV WL RTN RAIN SHWR CHCS SAT.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
SOUTHWESTERLY FLOW ALOFT WILL REMAIN IN PLACE THROUGH THE EXTENDED
AS SEVERAL SHORTWAVES DIVE SOUTH ACROSS THE INTERMOUNTAIN WEST AND
REINFORCE LONGWAVE TROUGHING. MODELS CONTINUE TO SHOW POOR
CONSENSUS IN HANDLING DETAILS...MAINLY WITH PLACEMENT RATHER THAN
TIME. A MORE BROADBRUSH WAS CONTINUED GIVE NT HIGH UNCERTAINTY BUT
IN GENERAL..FRONTAL SYSTEMS ARE PROGGED TO IMPACT THE REGION OVER
THE WEEKEND AND AGAIN LATE MONDAY / TUESDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
WITH THE FORECAST AREA STILL MOSTLY IN THE WARM SECTOR...VFR
CONDITIONS TO START FOR MOST TERMINALS. WITH THE EASTERN RIDGES ON
THE FRINGE OF CONTINUED DAMMING...LOWER CLOUDS AND EVEN SOME FOG
LINGER THERE. LLWS GROUPS INCLUDED AS SSW WINDS OF 40-50 LIE JUST
A COUPLE THOUSAND FEET OFF THE SURFACE.
WELL-ADVERTISED COLD FRONT WILL PUSH THROUGH DURING THE EVENING
HOURS BETWEEN 22Z AND 04Z. BAND OF LOW-TOPPED CONVECTION STILL
BEING FORECAST BY HRRR AND OTHER MODELS AND HAVE HANDLED THIS WITH
TWO HOUR TEMPO GROUPS IN EACH TAF. CIGS WILL DROP BACK TO MVFR AS
THE FRONT APPROACHES AND PASSES. MAIN ISSUE WILL BE THE
WIND...WITH S/SW GUSTS TO 40-45 KNOTS POSSIBLE WITH
CONVECTION..AND IMMEDIATELY FOLLOWING FROPA. WINDS WILL SLOWLY
DIMINISH WITH TIME OVERNIGHT BUT STILL EXPECT AT LEAST 20-30 KNOT
GUSTS THROUGH THE REMAINDER OF THE TAF PERIOD. MVFR CIGS WILL
CONTINUE...PERHAPS LOWERING TO IFR BY 12Z CLOSER TO LAKE ERIE.
LINGERING PRECIP WILL CHANGE OVER TO SNOW SHOWERS BY 12Z
AREAWIDE...BUT SIGNIFICANT RESTRICTIONS FROM SNOW ARE NOT FORECAST.
OUTLOOK.../WEDNESDAY NIGHT THROUGH MONDAY/...
CIG/VIS RESTRICTIONS THROUGH THURSDAY WILL IMPROVE TO VFR FRIDAY
AND CONTINUE UNTIL ANOTHER FRONTAL SYSTEM CROSSES THE REGION
SATURDAY AFTERNOON.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST THURSDAY FOR
MDZ001.
DENSE FOG ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MDZ001.
OH...WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST THURSDAY
FOR OHZ039>041-048>050-057>059-068-069.
PA...WIND ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST THURSDAY FOR
PAZ007>009-013>016-020>023-029-031-073>076.
WV...WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST THURSDAY
FOR WVZ001>004-012.
WIND ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST THURSDAY FOR
WVZ021>023-041.
DENSE FOG ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR WVZ023-
041.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1214 PM EST WED DEC 24 2014
.SYNOPSIS...
LOW PRESSURE STRENGTHENS WEST OF THE MOUNTAINS TODAY...AND . AN
ASSOCIATED COLD FRONT WILL CROSS THE AREA TONIGHT. HIGH PRESSURE
BUILDS BACK IN FROM THE SOUTHWEST CHRISTMAS DAY THROUGH FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST WX ANALYSIS CONTINUES TO FEATURE A DYNAMIC SYSTEM
TAKING SHAPE OVER THE DEEP SOUTH INTO THE TENNESSEE VALLEY AT
MIDDAY. LOCALLY...A RESIDUAL COOL-WEDGE AIRMASS IS HANGING TOUGH
ACROSS THE PIEDMONT, KEEPING TEMPS IN THE MID/UPPER 40S TO LOW 50S
ALONG AND W OF THE RIC METRO AREA. MEANWHILE, SFC WARM/COASTAL
FRONT IS MOVING ONSHORE WITH TEMPERATURES NOW WELL INTO THE
60S OVER SE VA & NE NC. WV SAT IMAGERY SHOWING BROAD SWATH OF WARM
CONVEYOR BELT MOISTURE LIFTING NORTH FROM THE EAST CENTRAL GULF
COAST ACROSS THE LOCAL AREA.
SFC LOW OVER THE SE CONUS WILL DEEPEN AND TRACK NNE INTO THE OHIO
VALLEY THROUGH THIS EVENING. BROAD SWATH OF MOISTURE WILL LIFT ENE
ACROSS THE REGION THROUGH THE BALANCE OF THE DAY, WITH PERIODIC
SHOWERS CONTINUING OVER THE PIEDMONT. THE NEW NAM/ARW IS A BIT
CLOSER IN HRRR DEPICTION OF BRIEF LULL IN PCPN BY LATE AFTN ON
INTO THE EARLY EVENING AS MID-LEVEL DRY SLOT, CURRENTLY LIFTING
ACROSS THE MID SOUTH INTO THE WESTERN CAROLINAS, SWINGS ACROSS
THE REGION. HOWEVER, PLENTY OF LLVL MOISTURE TO KEEP OVC WORDING
THROUGHOUT.
REGARDING CONVECTIVE POTENTIAL, HAVE CONFINED THUNDER WORDING TO
THE SE COASTAL PLAIN AFTER 20Z AS TEMPERATURES AND DEWPOINTS
CONTINUE TO RISE. SPC HAS ADDED THE SE IN A SLIGHT SEVERE RISK FOR
TONIGHT IN THE PRESENCE OF A WARM AND MOISTURE RICH AIRMASS AND A
STRONG 925-700MB WIND FIELD. DESPITE MEAGER SFC BASED INSTABILITY
WITH LACK OF CLOUD COVER, MID LVL SHEAR/HELICITY PARAMETERS WOULD
ARGUE FOR A CONTINUED THUNDER MENTION OVER THE COASTAL AREAS.
THUS, WL RETAIN SLIGHT CHC T OVER THE COASTAL PLAIN, MAINLY FOR
THE LATE AFTN AND EVENING HOURS.
THE COLD FRONT ARRIVES FROM THE W LATE THIS EVENING AND MOVES W-E
ACROSS THE AREA BETWEEN 03-06Z TONIGHT. DROPPED POPS OFF DURING
AFOREMENTIONED LULL PERIOD EARLY THIS EVENING, WITH MORE SCATTERED
RAIN SHRAS TO PERSIST LATER IN THE EVENING AND AFTER
MIDNIGHT...RAPIDLY DIMINISHING BEHIND THE FRONT AFTER 06Z TOWARDS
DAWN CHRISTMAS MORNING.
BY LATE AFTERNOON, EXPECT TEMPS TO RANGE FROM THE LOW TO MID 50S
WELL INLAND...MID/UPPER 60S FOR CENTRAL PORTIONS TO AROUND 70 SE.
THESE HIGHS WILL BE NEAR DAILY RECORDS...SEE THE CLIMATE SECTION
BELOW FOR DETAILS. GIVEN ONLY WEAK CAA, EXPECT TEMPS TO BE SLOW TO
DROP OFF OVERNIGHT, LIKELY LINGERING IN THE 50S AND 60S FOR MUCH
OF THE NIGHT.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
DRIER AIR ARRIVES CHRISTMAS MORNING AS HIGH PRESSURE BUILDS IN FROM
THE W. A SLOWER FRONTAL PASSAGE WILL RESULT IN A MILD CHRISTMAS
MORNING WITH LOWS RANGING FROM THE MID 40S FAR W...TO THE MID/UPPER
50S SE. THE SKY SHOULD BECOME MAINLY SUNNY WITH SCT AFTERNOON CU
ALONG WITH BREEZY WESTERLY FLOW BY MID/LATE MORNING CHRISTMAS DAY.
HIGHS SHOULD RANGE FROM THE MID 50S TO LOWER 60S CHRISTMAS DAY AS
CAA IS WEAK AND WILL BE OFFSET BY DOWNSLOPE WARMING (AND DUE TO A
WARM BEGINNING).
CLEAR/SEASONABLE THURSDAY NIGHT WITH LOWS IN THE UPPER 20S TO MID
30S. SURFACE HIGH PRESSURE SETTLES IMMEDIATELY OFF THE COAST FRIDAY
RESULTING IN LIMITED MIXING/LIGHT WINDS AND SUNNY CONDITIONS. HIGHS
SHOULD GENERALLY BE IN THE 50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE MODELS ARE IN GOOD AGREEMENT TO BEGIN THE PERIOD FRIDAY NIGHT
WITH THE STRONG RIDGING OVER THE SOUTHEASTERN US AND HIGH PRESSURE
OVER THE SOUTHEAST...CENTERED OVER EASTERN VA/NC. BUT THE MODELS
STRUGGLE WITH THE BREAKING DOWN OF THE RIDGE WITH THE GFS BREAKING
IT DOWN MUCH MORE QUICKLY THAN THE ECMWF. THE GFS ALLOW THE NEXT
COLD FRONT TO DROP INTO THE ARE SAT NIGHT AND MOVES IT SOUTH OF
THE REGION BY SUNDAY MORNING...SETTING UP AN OVERRUNNING PATTERN
SUNDAY AFTERNOON INTO MONDAY MORNING. THE ECMWF...AND THE 12Z IS
FURTHER NORTH WITH FEATURES THAN 00Z RUN...KEEPS THE RIDGE MUCH
STRONGER OVER THE SE AND DOES NOT ALLOW THE COLD FRONT TO MOVE
THROUGH THE AREA SAT NIGHT. IT STALLS THE FRONT OVER THE AREA ON
SUNDAY AND AS A WAVE OF LOW PRESSURE FORMS ALONG THE BOUNDARY AND
LIFTS NE INTO THE CENTRAL APPALACHIANS...IT PUSHES GULF MOISTURE
INTO THE AREA. THE 00Z ECMWF PUSHED THE WAVE OFF THE COAST BY
MONDAY...BUT THE 12Z RUN LIFTS THE LOW TO THE NORTH AND DRAGS A
COLD FRONT ACROSS THE REGION ON TUESDAY.
SO FOR NOW WITH THE GREAT SPREAD IN THE MODELS...HAVE TRENDED
TOWARD HPC/WPC GUIDANCE...WHICH IS SIMILAR TO THE 00Z ECMWF AND
BROUGHT THE WAVE INTO THE REGION ON SUNDAY AFTERNOON AND EVENING
WITH IT EXITING BY MONDAY AFTERNOON. HAVE INCREASED POPS TO 50%
FOR THAT PERIOD...KEEPING SATURDAY DRY. HAVE ALSO GONE DRY ON
MONDAY NIGHT INTO TUESDAY. THE BIG DIFFERENCE COMES TO
TEMPERATURES AS THE GFS WOULD ALLOW MUCH COLD AIR INTO THE REGION
BEGINNING ON SUNDAY THROUGH TUESDAY. THIS COULD ALSO POTENTIALLY
LEAD TO SOME WINTRY PCPN WITH WAVE ON SUNDAY NIGHT. FOR NOW HAVE
KEPT TEMPERATURES ABOVE FREEZING AND ALL RAIN WITH THE COLD AIR
BEING KEPT MORE TO THE NORTH. FOR TEMPERATURES HAVE ALLOW FOR A
GRADUAL COOL DOWN THROUGH THE PERIOD WITH THE COLDEST AIR ARRIVING
ON TUESDAY WITH HIGHS IN THE 40S.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 12Z...ANOTHER BAND OF RAIN WAS PROGRESSING INTO THE CWA FROM
THE SW. CIGS AND VSBYS WILL CONTINUE TO BE VARIABLE BUT ARE
EXPECTED TO BE PREDOMINANTLY IFR OR LOWER THIS MORNING. A BIT OF
IMPROVEMENT IS EXPECTED THIS AFTERNOON AS THE AREA BECOMES WARM
SECTORED BUT THE TAF SITES SHOULD BE MAINLY IFR IS STILL EXCEPT AT
ORF AND ECG. CONFIDENCE IN THE DEGREE OF IMPROVEMENT IS MARGINAL.
A COLD FRONT APPROACHES FROM THE WEST TONIGHT WITH SHOWERS AND A
SLGT CHC OF THUNDER (THIS PCPN NOT INCLUDED IN THE TAF).
CONDITIONS IMPROVE FROM THE WEST IN THE MORNING AS WINDS TURN TO
WESTERLY.
OUTLOOK...HIGH PRESSURE DOMINATES THURSDAY AFTERNOON THROUGH
SATURDAY WITH DRY WEATHER. A CHC FOR RAIN RETURNS SUNDAY AS LOW
PRESSURE APPROACHES FROM THE WEST.
&&
.MARINE...
DENSE FOG ADVISORY IS IN EFFECT FOR THE MARINE AREA THROUGH LATE
THIS AFTERNOON AS WARM MOIST AIR MOVES OVER THE RELATIVELY COOL
WATERS.
AS OF 11Z...WINDS WERE BEGINNING TO INCREASE FROM THE SE. SCA
STARTED AT 15Z FOR THE MOUTH OF THE BAY AS WAVES WILL SOON REACH 4
FT IN THE CHANNEL.
PREVIOUS DISCUSSION...
AS OF 08Z...WINDS REMAIN LIGHT OVER THE MARINE AREA BUT ARE FORECAST
TO INCREASE FROM THE SE AND THEN S THIS MORNING AS A WARM FRONT
MOVES N THROUGH THE WATERS AND LOW PRESSURE DEEPENS OVER THE OHIO
VALLEY. SCA IS IN EFFECT FOR ALL THE WATERS EXCEPT THE RIVERS SAVE
THE LOWER JAMES. SCA CONDITIONS OVER INLAND WATERS MAY BE MINIMAL
AT FIRST DUE TO LIMITED MIXING BUT WILL BECOME MORE FAVORABLE
THURSDAY MORNING. HAVE ADDED THE LOWER JAMES WITH TIMES STAGGERED
SLIGHTLY FROM THE BAY (STARTING AT 21Z TODAY AND ENDING 3 HOURS
EARLIER THURSDAY). LATER SHIFTS MAY NEED TO CONSIDER SCA BEHIND
THE COLD FRONT FOR OTHER RIVER ZONES ON THURSDAY MORNING.
SCA IS ALREADY IN EFFECT N OF PARRAMORE ISLAND. SEAS ARE EXPECTED TO
BUILD TO 5 FT OR HIGHER BY 18Z S OF THERE AND DECIDED TO BEGIN SCA S
OF PARRAMORE ISLAND AT 15Z TO ALLOW SUFFICIENT CUSHION.
HIGH PRESSURE THEN BUILDS INTO THE REGION ON THURSDAY NIGHT AND
LINGERS THROUGH SATURDAY AS A STRONG UPPER LEVEL RIDGE BUILDS INTO
THE SOUTHEASTERN US AND KEEPS STRONG HIGH PRESSURE AT THE SURFACE
OVER THE REGION THROUGH SATURDAY. LOW PRESSURE APPROACHES FROM THE
SW SUNDAY AND MOVES ACROSS THE REGION MONDAY. PRELIMINARY
INDICATIONS DO NOT INDICATE THAT A SCA WILL BE NEEDED WITH THIS
SYSTEM.
&&
.TIDES/COASTAL FLOODING...
WATER LEVELS AT BISHOPS HEAD AND CAMBRIDGE ARE EXPECTED TO
APPROACH MINOR FLOODING LATE TODAY AND EARLY THIS EVENING.
&&
.CLIMATE...
RECORD HIGHS FOR CHRISTMAS EVE/WED 12/24:
RICHMOND.......71 F (1988)
NORFOLK........75 F (1891)
SALISBURY......67 F (1990)
ELIZ CITY NC...75 F (1990)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...COASTAL FLOOD ADVISORY UNTIL 8 PM EST THIS EVENING FOR
MDZ021>023.
NC...NONE.
VA...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ630>638-
650-652-654-656-658.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THURSDAY FOR ANZ633-634-
650-652-654-656-658.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THURSDAY FOR ANZ630>632.
SMALL CRAFT ADVISORY UNTIL 1 PM EST THURSDAY FOR ANZ638.
&&
$$
SYNOPSIS...AJZ/ALB
NEAR TERM...AJZ/MAM
SHORT TERM...AJZ/LKB
LONG TERM...ESS
AVIATION...LSA
MARINE...LSA
TIDES/COASTAL FLOODING...
CLIMATE...
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
325 PM CST Wed Dec 24 2014
.SHORT TERM: (Through Tonight)
Issued at 325 PM CST Wed Dec 24 2014
An area of light rain possibly mixed with a few wet snowflakes
currently centered through St. Louis was moving east around 25-30
kts. This precipitation is occuring in association with a trailing
vort max within the cyclonic flow on the backside of the exiting
upper trof. Present indications are it should have exited or just
about exited the eastern CWA counties in south central/southwest IL
at 00z. There might be some lingering patchy drizzle for a few hours
into early evening. Satellite imagery has stratus hanging tough and
still well back into eastern KS and eastern OK at 21z. Trends along
with the RAP and NAM 925 mb RH suggests the clearing trend will be
slow and won`t commence in our CWA until well after midnight, and
the back edge of clouds around 50 miles west of STL at 12z Thursday.
The clouds will help keep temperatures a tad warmer overnight than
the previous forecast.
Glass
.LONG TERM: (Thursday through Next Wednesday)
Issued at 325 PM CST Wed Dec 24 2014
(Thursday through Saturday)
Primary focus thru this period will be precip chances late in the
period.
Mdls remain in good agreement thru Fri. Sfc winds quickly become sly
by tomorrow as ridge quickly moves off to the E. Expect current
cloud deck to move ewd tonight and shud be along/near the MS River
around 12z Thurs. These clouds shud be on the ern boarder of the CWA
by 18z. However, mdls suggest these low clouds will probably be
replaced with CI which shud hinder heating somewhat. Have therefore
kept temps twd the cooler guidance, esp across ern portions of the
CWA will clouds will linger. For Fri, have trended slightly warmer
as strong sly winds will be in place. However, with questions
regarding cloud cover, did not go as high as warmer MOS for now.
Cut off low over srn Rockies begins to open and eject into the
Plains by Fri evening. However, the GEM is a slower soln and
actually redevelops an upper low after the initial s/w is reaching
the nrn Plains. As this soln is an outlier, have trended away from
this soln and twd the other mdls which remain in good agreement.
Have kept PoPs in lower chance category for now as mdl soundings
suggest much of the QPF may be more DZ than RA. Not to mention that
the NAM and local WRF suggest the precip bifurcating with a branch
to the N and one to the S. However, with the trof approaching and
some low level forcing, light RA will be possible. Question becomes
p-types on Sat and Sat night as the cold air filters into the
region. While the GFS soundings suggest precip will end as a brief
period of IP, then SN, setup is typical of this area where precip
will likely end as RA just ahead of the surge of cold air. This is
more likely given the sfc ridge center is currently progd to be over
wrn KS. Regardless, close attention shud be paid to this time period
as mdls come into better agreement.
(Sunday through Wednesday)
Focus quickly turns to temps thru this period.
Will continue trends twd a GFS/ECMWF compromise due to issues with
the GEM mentioned above. The DGEX also becomes a fast outlier as the
next trof ejects into the Plains sometime on Wed.
Relatively cold air moves in place behind the cdfnt on Sat. A
secondary cdfnt is expected to push thru the region Sun night into
Mon ahead of the next system approaching the region late Mon night
into Wed. Have trended temps twd cooler guidance for Tues and beyond
placing temps nearly 20 degrees below seasonal avg.
A number of questions arise with the system on Tues/Wed. The GFS
cuts off an upper low over the swrn U.S. which it is known to do.
The ECMWF ejects this trof into the Plains, but given the weakening
jet upstream of this trof, am not convinced this soln is correct.
With both mdls suggesting very low QPF, will keep only slight chance
PoPs going for now with plenty of time to adjust. The one item both
mdls do agree on is the precip is expected to be all SN.
Tilly
&&
.AVIATION: (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1135 AM CST Wed Dec 24 2014
The back edge of IFR flight conditions was near a KVFR-KFSW line
late this morning with MVFR conditions extending well west into
the Plains. IFR flight conditions with light rain/drizzle and
possibly a few snowflakes will be predominate through the afternoon
across eastern MO into western IL including the St. Louis area
terminals. Conditions will be improving to MVFR during the afternoon
in central MO including KCOU. MVFR conditions will prevail much of
tonight at all terminals with gradual clearing and improvement to
VFR from late tonight into just past daybreak on Thursday.
Specifics for KSTL:
IFR flight conditions with light rain/drizzle will prevail through
the afternoon. I can`t rule out a few snowflakes but nothing of
significance is currently anticipated. Conditions will be improving
to MVFR by early evening and then prevail tonight. Clearing and
improvement to VFR is currently expected just past daybreak on
Thursday with increasing southerly winds during the day on Thursday.
Glass
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 32 50 38 53 / 10 0 0 10
Quincy 29 46 36 49 / 10 0 0 10
Columbia 29 50 39 51 / 10 0 0 10
Jefferson City 30 51 39 52 / 10 0 0 10
Salem 33 45 36 50 / 30 0 0 10
Farmington 31 47 38 51 / 10 0 0 10
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ELKO NV
215 PM PST WED DEC 24 2014
.SYNOPSIS...ON THE LATEST SATELLITE IMAGE THERE IS A SHIELD OF
CLOUDS FROM UTAH TO THE PACIFIC OCEAN. THIS LOW PRESSURE SYSTEM WILL
DELIVER A BATCH OF WINTRY WEATHER THIS EVENING....OVER NIGHT AND
TOMORROW. THE BULK OF THE SNOW IS ANTICIPATED OVER NIGHT. IN
ADDITION TO SNOW...EXPECTING GUSTY WINDS...BLOWING SNOW AND BRUTALLY
COLD TEMPERATURES.
&&
.SHORT TERM...TONIGHT THROUGH SATURDAY. AS ADVERTISED...EXPECTING A
SIGNIFICANT WINTER WEATHER STORM THIS EVENING...OVER NIGHT AND INTO
TOMORROW. THE NAM...THE GFS AND THE RAP ARE PRETTY CONSISTENT
BRINGING THE QPF INTO THE LKN CWA AFTER 4 PM TODAY. THE GFS ENSEMBLE
MEMBERS ARE TIGHTLY CLUSTERED WITH THE PLACEMENT OF THE SURFACE LOW
OVER NE NV...WHEREAS THE ECMWF INDIVIDUAL MEMBERS ARE ROUGHLY 50 TO
100 MILES SOUTH OF THE GFS MEAN. LITTLE SUBTLE DIFFERENCES LIKE THIS
WILL MAKE THE DIFFERENCE IN FINAL SNOW TOTAL ACCUMULATIONS. THE NCEP
RMOP IS WELL INTO BLUE TERRITIORY EVEN AT 24 HRS. BUT THE DYNAMICS
ARE IN PLACE FOR A SNOW AND WIND EVENT. KEPT HEADLINES IN
PLACE...BUT ADDED AN NPW FOR NORTHERN NYE. IN THE WAKE OF THE
FRONTAL PASSAGE...EXPECTING CAA AND ROBUST NORTHERLY FLOW.
.LONG TERM...SATURDAY NIGHT THROUGH NEXT WEDNESDAY. EC AND GFS IN
FAIRLY GOOD AGREEMENT WITH THE OVERALL PATTERN. EXPECT VERY COLD
AND LARGELY DRY WEATHER ACROSS NEVADA THIS WEEKEND AND INTO NEXT
WEEK. COLD FRONT DROPPING SOUTH FROM CANADA WILL IS EXPECTED TO BE
JUST NORTH OF THE IDAHO-NEVADA BORDER SATURDAY NIGHT. THE VERY COLD
PART OF THE AIRMASS ASSOCIATED WITH AN ARCTIC AIRMASS BEGINS TO MOVE
INTO CWA DURING THE DAY SUNDAY. SINCE THE AIRMASS IS COLD AND WITH
SOME LOW LEVEL MOISTURE AVAILABLE...EXPECT JUST MAINLY LIGHT SNOW
WITH HEAVIEST AMOUNTS IN THE UPSLOPE FAVORABLE AREAS THROUGH MONDAY.
THE COLD AIRMASS IS REINFORCED AND CONTINUES TO PUSH SOUTH OVER THE
CWA AS THE 700 MB TEMPERATURES DROP NEAR -20C BY MONDAY AFTERNOON.
WITH SNOW COVER...DAYTIME TEMPERATURES MONDAY IS EXPECTED TO BE ONLY
IN THE LOW 20S AND TUESDAY WILL BE LUCKY TO MAKE IT TO THE 20 DEGREE
MARK. HAVE DROP LOW TEMPERATURES 5 TO 15 DEGREES NEXT TUESDAY AND
WEDNESDAY WITH LOWS SHOULD BE -15 BELOW ZERO TO NEAR ZERO MOST
LOCATIONS TUESDAY AND WEDNESDAY MORNINGS. JH
&&
.AVIATION...CIGS WILL LOWER THIS EVENING WITH COLD FRONT EXPECTED TO
PUSH INTO WMC AROUND 01-02Z...EKO 03-04Z AND AROUND ELY 05-06Z.
AHEAD OF THE COLD FRONT...S/SW WINDS OF 15 TO 25KTS WITH G40KTS AT
ALL TAF SITES...FOLLOWED BY SEVERAL HOURS OF IFR/LIFR IN SN/BLSN AT
KWMC...KEKO AND KELY BEHIND THE FRONT. AFTER THE FRONTAL PASSAGE
AROUND 05Z...STRONG GUSTY NE WINDS OF 35 TO 45 KNOTS AT TPH WILL
DEVELOP. THESE GUSTY WINDS WILL CONTINUE THROUGH AT LEAST THURSDAY
AFTERNOON.
ADDITIONALLY...THIS EVENING AND OVER NIGHT...EXPECTING SNOW TO
ACCUMULATE ON THE RUNWAYS OF KEKO. THIS IS A HIGH CONFIDENCE
EVENT...AND SNOW IS VISIBLE OVER NE NV ON THE LATEST RADAR IMAGE.
ADDITIONAL IMPACTS TO THE AVIATION CUSTOMERS WILL
INCLUDE...OBSCURED MT TOPS...LIGHT TO OCNL MODERATE TURBULENCE
AND LIGHT TO MODERATE ICING. THIS STORM WILL ALSO IMPACT SLC ON
THURSDAY/FRIDAY...POSSIBLY IMPACTING COMMERCIAL TRAFFIC BETWEEN
EKO AND SLC.
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 4 PM PST
THURSDAY FOR NORTHERN ELKO COUNTY-SOUTH CENTRAL ELKO COUNTY-
SOUTHWEST ELKO COUNTY-WHITE PINE COUNTY.
WINTER WEATHER ADVISORY UNTIL 10 AM PST THURSDAY FOR HUMBOLDT
COUNTY-NORTHERN LANDER COUNTY AND NORTHERN EUREKA COUNTY-
SOUTHERN LANDER COUNTY AND SOUTHERN EUREKA COUNTY.
WIND ADVISORY FROM 1 AM TO 4 PM PST THURSDAY FOR SOUTHEASTERN
ELKO COUNTY.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 4 PM PST THURSDAY
FOR RUBY MOUNTAINS AND EAST HUMBOLDT RANGE.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM PST
THURSDAY FOR NORTHEASTERN NYE COUNTY-NORTHWESTERN NYE COUNTY.
WIND ADVISORY FROM 10 PM THIS EVENING TO 4 PM PST THURSDAY FOR
NORTHEASTERN NYE COUNTY-NORTHWESTERN NYE COUNTY.
&&
$$
97/87/87
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
320 PM EST WED DEC 24 2014
.SYNOPSIS...
A STORM SYSTEM OVER THE EASTERN GREAT LAKES WILL BRING RAIN TO
OUR REGION THROUGH TONIGHT. A COLD FRONT EARLY CHRISTMAS
MORNING WILL BRING RAIN SHOWERS AND EVEN A FEW THUNDERSTORMS WITH
GUSTY WINDS. IT WILL BE WINDY AND CHILLY FOR THE REMAINDER OF
CHRISTMAS DAY WITH A CHANCE OF RAIN AND SNOW SHOWERS. A RIDGE OF
HIGH PRESSURE WILL BRING FAIR WEATHER TO OUR REGION ON FRIDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
RADARS SHOW PLENTY OF LIGHT RAIN WITH SOME PATCHES OF HEAVIER RAIN
MAINLY ACRS THE ERN 1/2 OF PA AND E OF I-81 IN C NY. THE RAIN WILL
CONT TO TRACK N TO NORTHEASTWARD INTO THE EVENING AND THERE LIKELY
WILL BE A LULL IN THE PRECIPITATION FOR MOST OF OUR AREA BY 00Z
WITH JUST SOME SPOTTY LIGHT RAIN SHOWERS AT BEST. THIS INITIAL
SHOT OF PRECIPITATION WAS ASSOCIATED WITH A SHORT WAVE RIPPLING
NORTHEASTWARD ACRS NY/PA. THIS FEATURE WAS SEEN WELL IN THE 850 MB WIND
FIELDS SHOW A LOW LEVEL WIND MAX ACRS PA AND NY POINTING INTO THE
RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET STREAK OVER OUR AREA.
ONCE THIS LIFTS NE OF THE REGION LATER THIS AFTERNOON...THERE WILL BE A
LULL IN THE PRECIP UNTIL THE COLD FRONT WHICH WAS PRESENTLY
EXTENDED FROM SERN LWR MI TO FAR WRN OH TO CNTRL KY RACES
EASTWARD IN ASSCTN WITH A STRG UPPER LEVEL WAVE THAT WILL PASS THRU
THE REGION LATER TONIGHT. THIS FEATURE WILL BE THE IMPETUS TO
FORCE THIS FRONT THRU BETWEEN 3 AND 9Z ACRS C NY AND NE PA.
AS THIS UPPER LEVEL FEATURE WORKS E...IT WILL ACCELERATE THE LOW-
LEVEL WINDS TO ARND 60 TO 65 KNOTS AT 850 MB AS PER THE NAM JUST
IN ADVANCE OF THE FRONT. INDEED THE WINDS FROM THE LOWER TO MIDDLE
TROPOSPHERE WILL BE RACING AHEAD OF THIS FRONT LEADING TO
IMPRESSIVE SHEAR PROFILES. THE 0-1 KM SHEAR WAS PROGGED TO BE AT
50 KNOTS...WITH THE 0-3 KM SHEAR AT ABT THE SAME OF 50 KNOTS WITH
THE 0-5 KM SHEAR (MODEL SOUNDINGS ONLY HAVE EQUILIBRIUM LEVELS AT
ABT 5 KM)...OF 75 TO 80 KNOTS. TRADITIONAL 0-6KM SHEAR WHICH MIGHT
NOT APPLY AS MUCH HERE WUD BE ALMOST 100 KNOTS. MAIN PROBLEM IS
HOW UNSTABLE WITH THE LOWER AMS GET IN ADVANCE OF THIS FRNT. THERE
WILL BE INTENSE LL MOISTURE ADVECTION BUT IT WILL BE FAIRLY WARM
ALOFT FOR THIS TIME OF THE YEAR. MODEL SOUNDINGS LOOK ALMOST MOIST
ADIABATIC AHEAD OF FRONT WITH CAPES GENERALLY LESS THAN 100 J/KG.
HIGH RES CONVECTION ALLOWING MODELS INCLUDING THE HRRR (UNTIL 7Z)
AND THE WRFNMM AND WRFARW THRU 12Z THU ARE NOT SHWG ANY
ORGANIZED LINEAR CONVECTION LIKE PREVIOUS RUNS. FOR NOW WILL
CONTINUE MENTION OF THUNDER AND GUSTY WINDS IN FORECASTS AND
MENTION IN HWO AS IT WUD NOT TAKE MUCH TO MIX STRG WINDS DOWN.
EVENING SHIFT WILL HAVE TO MONITOR FOR THE DEVELOPMENT. IF A
SQUALL LINE DOES DEVELOP AND RACES EAST IT CUD SPELL A LOT OF
TROUBLE WITH HIGH WINDS.
AFTER FROPA...GRADIENT WINDS WILL PICK UP AND WE WILL SEE
LINGERING RAIN SHOWERS IN THE BACKLASH MOISTURE ACRS C NY AND NE
PA THU AM. TEMPERATURES WILL SLOWLY FALL AND THE RAIN WILL MIX
WITH SOME SNOW AT TIMES LATER IN THE DAY. WILL CONTINUE WIND
ADVISORIES FOR CHRISTMASN DAY AS WE CAN EASILY SEE WIND GUSTS
BETWEEN 40 AND 50 MPH ACRS OUR NRN 1/2 OF OUR FORECAST AREA MAINLY
N OF BGM AND ELM.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
FOR THURSDAY NIGHT WINDS DIE DOWN AND ANY LINGERING SNSH OFF LAKE
ONTARIO WILL DIE DOWN AS HIGH PRESSURE BUILDS SOUTH OF THE REGION
WITH RIDGING NOSING NORTHWARD. TEMPERATURES WILL REMAIN ABOVE
NORMAL AS OUR AREA REMAINS UNDER A PACIFIC AIRMASS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
GFS/ECWMF HAVE COME INTO BETTER AGREEMENT WITH THE LATEST MODEL
RUNS... INDICATING A FRONTAL PASSAGE LATE SATURDAY NIGHT THROUGH
SUNDAY FOLLOWED BY A RATHER QUIET EXTENDED FORECAST PERIOD
DOMINATED BY CANADIAN HIGH PRESSURE. SATURDAY WILL FEATURE DRY AND
UNSEASONABLY WARM WEATHER WITH HIGH TEMPERATURES APPROACHING 50 IN
MANY PLACES. A COLD FRONT IS FORECAST TO CROSS THE AREA LATE
SATURDAY NIGHT OR SUNDAY MORNING ACCOMPANIED BY A FEW SHOWERS.
COLDER AIR WILL THEN GRADUALLY FILTER SOUTHEAST ACROSS THE AREA
SUNDAY THROUGH TUESDAY. 850 MB TEMPERATURES ARE FORECAST TO FALL
TO AROUND -10 TO -12 OVER LAKE ONTARIO BY MONDAY BUT THE FLOW WILL
BE STRONGLY ANTICYCLONIC IMPLYING LOTS OF DRY AIR AND LOW
INVERSION HEIGHTS WITH LAKE EFFECT SNOW POTENTIAL AT A MINIMUM.
MEANWHILE A SERIES OF WAVES ARE FOERCAST TO TRACK WELL SOUTH OF
OUR AREA WITH PRECIPITATION REMAINING SOUTH OF THE MASON-DIXON
LINE. IF THIS PATTERN IS REALIZED... A COOL MOSTLY DRY PERIOD CAN
BE EXPECTED WITH TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
UPDATED AT 1 PM... PERIODS OF RAIN AND DRIZZLE WILL PERSIST THIS
AFTERNOON IN A MILD MOIST FLOW PATTERN ACROSS THE AREA. CONDITIONS
WILL BE MOSTLY MVFR WITH AREAS OF IFR MOST COMMON AT HILLTOP
AIRPORTS SUCH AS BGM. 40 KT SOUTHERLY WINDS AT 2000 FEET AGL WILL
ALSO RESULT IN LOW LEVEL WIND SHEAR. A PERIOD OF MOSTLY DRY
WEATHER CAN BE EXPECTED THIS EVENING WITH MOSTLY MVFR CIGS AND
VSBYS... THEN A COLD FRONT WILL MOVE ACROSS THE AREA FROM 04Z-08Z
WITH HEAVIER SHOWERS AND GUSTY WINDS SHIFTING TO THE WEST. AFTER A
BRIEF PERIOD OF CLEARING... CLOUDS WILL OVERSPREAD THE AREA AGAIN
CHRISTMAS MORNING WITH MVFR CIGS.
WINDS WILL BE LIGHT FROM THE SOUTH-EAST TODAY THROUGH THIS
EVENING. A COLD FRONTAL PASSAGE BETWEEN 04Z-08Z WILL BE
ACCOMPANIED BY A WIND SHIFT TO WESTERLY WITH GUSTS OF 30-35 KTS IN
HEAVIER SHOWERS... THEN WESTERLY WINDS WILL CONTINUE THROUGH
CHRISTMAS DAY AVERAGING 10 TO 20 KTS WITH GUSTS TO 30 KTS.
OUTLOOK...
THU...BECOMING VFR/MVFR. WINDY WITH RAIN SHOWERS.
FRI/SAT...VFR.
SAT NGT TO SUN...MVFR/IFR. CHC RAIN OR SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WIND ADVISORY FROM 5 AM TO 7 PM EST THURSDAY FOR NYZ009-
015>018-022-023-025-036-037-044>046-057.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...DJN
LONG TERM...MSE
AVIATION...MSE
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
140 PM EST WED DEC 24 2014
.SYNOPSIS...
A STORM SYSTEM OVER THE EASTERN GREAT LAKES WILL BRING RAIN TO
OUR REGION THROUGH TONIGHT. A COLD FRONT EARLY CHRISTMAS
MORNING WILL BRING RAIN SHOWERS AND EVEN A FEW THUNDERSTORMS WITH
GUSTY WINDS. IT WILL BE WINDY AND CHILLY FOR THE REMAINDER OF
CHRISTMAS DAY WITH A CHANCE OF RAIN AND SNOW SHOWERS. A RIDGE OF
HIGH PRESSURE WILL BRING FAIR WEATHER TO OUR REGION ON FRIDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
RADARS SHOW PLENTY OF LIGHT RAIN WITH SOME PATCHES OF HEAVIER RAIN
MAINLY ACRS THE ERN 1/2 OF PA AND E OF I-81 IN C NY. THE RAIN WILL
CONT TO TRACK N TO NORTHEASTWARD INTO THE EVENING AND THERE LIKELY
WILL BE A LULL IN THE PRECIPITATION FOR MOST OF OUR AREA BY 00Z
WITH JUST SOME SPOTTY LIGHT RAIN SHOWERS AT BEST. THIS INITIAL
SHOT OF PRECIPITATION WAS ASSOCIATED WITH A SHORT WAVE RIPPLING
NORTHEASTWARD ACRS NY/PA. THIS FEATURE WAS SEEN WELL IN THE 850 MB WIND
FIELDS SHOW A LOW LEVEL WIND MAX ACRS PA AND NY POINTING INTO THE
RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET STREAK OVER OUR AREA.
ONCE THIS LIFTS NE OF THE REGION LATER THIS AFTERNOON...THERE WILL BE A
LULL IN THE PRECIP UNTIL THE COLD FRONT WHICH WAS PRESENTLY
EXTENDED FROM SERN LWR MI TO FAR WRN OH TO CNTRL KY RACES
EASTWARD IN ASSCTN WITH A STRG UPPER LEVEL WAVE THAT WILL PASS THRU
THE REGION LATER TONIGHT. THIS FEATURE WILL BE THE IMPETUS TO
FORCE THIS FRONT THRU BETWEEN 3 AND 9Z ACRS C NY AND NE PA.
AS THIS UPPER LEVEL FEATURE WORKS E...IT WILL ACCELERATE THE LOW-
LEVEL WINDS TO ARND 60 TO 65 KNOTS AT 850 MB AS PER THE NAM JUST
IN ADVANCE OF THE FRONT. INDEED THE WINDS FROM THE LOWER TO MIDDLE
TROPOSPHERE WILL BE RACING AHEAD OF THIS FRONT LEADING TO
IMPRESSIVE SHEAR PROFILES. THE 0-1 KM SHEAR WAS PROGGED TO BE AT
50 KNOTS...WITH THE 0-3 KM SHEAR AT ABT THE SAME OF 50 KNOTS WITH
THE 0-5 KM SHEAR (MODEL SOUNDINGS ONLY HAVE EQUILIBRIUM LEVELS AT
ABT 5 KM)...OF 75 TO 80 KNOTS. TRADITIONAL 0-6KM SHEAR WHICH MIGHT
NOT APPLY AS MUCH HERE WUD BE ALMOST 100 KNOTS. MAIN PROBLEM IS
HOW UNSTABLE WITH THE LOWER AMS GET IN ADVANCE OF THIS FRNT. THERE
WILL BE INTENSE LL MOISTURE ADVECTION BUT IT WILL BE FAIRLY WARM
ALOFT FOR THIS TIME OF THE YEAR. MODEL SOUNDINGS LOOK ALMOST MOIST
ADIABATIC AHEAD OF FRONT WITH CAPES GENERALLY LESS THAN 100 J/KG.
HIGH RES CONVECTION ALLOWING MODELS INCLUDING THE HRRR (UNTIL 7Z)
AND THE WRFNMM AND WRFARW THRU 12Z THU ARE NOT SHWG ANY
ORGANIZED LINEAR CONVECTION LIKE PREVIOUS RUNS. FOR NOW WILL
CONTINUE MENTION OF THUNDER AND GUSTY WINDS IN FORECASTS AND
MENTION IN HWO AS IT WUD NOT TAKE MUCH TO MIX STRG WINDS DOWN.
EVENING SHIFT WILL HAVE TO MONITOR FOR THE DEVELOPMENT. IF A
SQUALL LINE DOES DEVELOP AND RACES EAST IT CUD SPELL A LOT OF
TROUBLE WITH HIGH WINDS.
AFTER FROPA...GRADIENT WINDS WILL PICK UP AND WE WILL SEE
LINGERING RAIN SHOWERS IN THE BACKLASH MOISTURE ACRS C NY AND NE
PA THU AM. TEMPERATURES WILL SLOWLY FALL AND THE RAIN WILL MIX
WITH SOME SNOW AT TIMES LATER IN THE DAY. WILL CONTINUE WIND
ADVISORIES FOR CHRISTMASN DAY AS WE CAN EASILY SEE WIND GUSTS
BETWEEN 40 AND 50 MPH ACRS OUR NRN 1/2 OF OUR FORECAST AREA MAINLY
N OF BGM AND ELM.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
FOR THURSDAY NIGHT WINDS DIE DOWN AND ANY LINGERING SNSH OFF LAKE
ONTARIO WILL DIE DOWN AS HIGH PRESSURE BUILDS SOUTH OF THE REGION
WITH RIDGING NOSING NORTHWARD. TEMPERATURES WILL REMAIN ABOVE
NORMAL AS OUR AREA REMAINS UNDER A PACIFIC AIRMASS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
130 AM UPDATE...
LITTLE CHANGE. WPC GUIDANCE FOLLOWED THE SAME TUNE. TRICKY PART
WILL BE LOW LEVEL TEMPERATURES AND WHAT PRECIP TYPES EACH SYSTEM
WILL HAVE. TEMPERATURES WAVER AROUND FREEZING DEPENDING ON THE
STORM TRACKS. COOLING TUESDAY AND WEDNESDAY SO PROBABLY BY THEN
ALL SNOW AND BELOW NORMAL TEMPERATURES.
PREVIOUS DISCUSSION...
THE OVERALL 500 MB PATTERN DOES NOT CHANGE MUCH THROUGH THIS
PERIOD WITH A BROAD TROF RESIDENT OVER CENTRAL NORTH AMERICA WITH
RELATIVELY MILD SWLY FLOW ACROSS THE CNY/NEPA REGION. THIS WILL
KEEP US IN A RATHER ACTIVE PATTERN WITH TRANSIENT WEATHER SYSTEMS
MOVING THROUGH THE REGION.
MEDIUM RANGE MODEL CONSENSUS IS RATHER POOR...BUT IT DOES APPEAR
THE BEST CHANCE FOR PRECIPITATION WILL BE SAT NIGHT-SUN ASSOCIATED
WITH A COLD FRONT...AND THEN A MORE MARGINAL EVENT SLATED FOR
MONDAY AS LOW PRESSURE LIFTS THROUGH THE TN/OH VALLEY PER THE
ECMWF. THIS IS UNLESS THE GFS/GGEM CONTINUE TO TREND A FLATTER
WAVE OUT TO SEA TO OUR SOUTH MISSING US COMPLETELY. WPC GRIDS SEEM
TO BE HEAVY HANDED ON THE ECMWF SOLUTIONS...BUT GIVEN UNCERTAINTY
INTRODUCED BY GFS/GGEM...WE HAVE SOFTENED THEM TO CHANCE POPS IN
THIS AREA FROM SUN-MON NGT. BEYOND THEN...WEAK WAVES AND PASSING
FLURRIES POSSIBLE THROUGH MID-WEEK.
OVERALL...TEMPERATURES WITHIN THE BROAD SWLY FLOW WILL BE NEAR TO
ABOVE LATE DECEMBER NORMALS.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
UPDATED AT 1 PM... PERIODS OF RAIN AND DRIZZLE WILL PERSIST THIS
AFTERNOON IN A MILD MOIST FLOW PATTERN ACROSS THE AREA. CONDITIONS
WILL BE MOSTLY MVFR WITH AREAS OF IFR MOST COMMON AT HILLTOP
AIRPORTS SUCH AS BGM. 40 KT SOUTHERLY WINDS AT 2000 FEET AGL WILL
ALSO RESULT IN LOW LEVEL WIND SHEAR. A PERIOD OF MOSTLY DRY
WEATHER CAN BE EXPECTED THIS EVENING WITH MOSTLY MVFR CIGS AND
VSBYS... THEN A COLD FRONT WILL MOVE ACROSS THE AREA FROM 04Z-08Z
WITH HEAVIER SHOWERS AND GUSTY WINDS SHIFTING TO THE WEST. AFTER A
BRIEF PERIOD OF CLEARING... CLOUDS WILL OVERSPREAD THE AREA AGAIN
CHRISTMAS MORNING WITH MVFR CIGS.
WINDS WILL BE LIGHT FROM THE SOUTH-EAST TODAY THROUGH THIS
EVENING. A COLD FRONTAL PASSAGE BETWEEN 04Z-08Z WILL BE
ACCOMPANIED BY A WIND SHIFT TO WESTERLY WITH GUSTS OF 30-35 KTS IN
HEAVIER SHOWERS... THEN WESTERLY WINDS WILL CONTINUE THROUGH
CHRISTMAS DAY AVERAGING 10 TO 20 KTS WITH GUSTS TO 30 KTS.
OUTLOOK...
THU...BECOMING VFR/MVFR. WINDY WITH RAIN SHOWERS.
FRI/SAT...VFR.
SAT NGT TO SUN...MVFR/IFR. CHC RAIN OR SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WIND ADVISORY FROM 5 AM TO 7 PM EST THURSDAY FOR NYZ009-
015>018-022-023-025-036-037-044>046-057.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...DJN
LONG TERM...JAB/TAC
AVIATION...MSE/TAC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1210 PM EST WED DEC 24 2014
.SYNOPSIS...A WARM FRONT WILL LIFT NORTHWARD THROUGH THE CAROLINAS
TODAY AS A DEEPENING LOW PRESSURE SYSTEM TRACKS INTO THE TENNESSEE
VALLEY. A COLD FRONT WILL SURGE EAST ACROSS THE REGION TONIGHT AS
THE SURFACE LOW PROGRESSES NORTHWARD THROUGH THE OHIO VALLEY INTO
THE GREAT LAKES.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 1050 AM WEDNESDAY...
LARGE WARM CONVEYOR BELT PRECIP SHIELD STRETCHES FROM THE MID-
ATLANTIC COAST TO THE GULF OF MEXICO...WITH AN EMBEDDED QLCS FROM
SOUTH CAROLINA THROUGH THE FLORIDA PANHANDLE. MEANWHILE...THE WEDGE
AND COASTAL FRONTS CONTINUE THEIR RETREAT THROUGH THE COASTAL PLAIN
AND INTO THE PIEDMONT THIS MORNING...LEADING TO A STRONG BAROCLINIC
ZONE JUST EAST OF THE US-1 CORRIDOR. TEMPS ARE STILL IN THE MID 40S
NORTHWEST TO NOW UPPER 60S SOUTHEAST. THE BULK OF THE PRECIP WILL
CONTINUE TO SHIFT EAST THROUGH EARLY AFTERNOON IN CONCERT WITH THE
LOW-LEVEL JET....WITH SOME ENHANCEMENT ALONG THE AFOREMENTIONED
FRONTAL ZONE. A LULL IN PRECIP IS ANTICIPATED THIS AFTERNOON ON THE
HEELS OF THE LOW-LEVEL JET...WITH FORCING SOMEWHAT LIMITED GIVEN
THAT THE POSITIVELY TILTED UPPER TROUGH OVER THE MISSISSIPPI RIVER
VALLEY DOESNT MAKE ITS STRONG EASTWARD PUSH UNTIL TONIGHT. MOST OF
THE CAM`S SUPPORT THIS IDEA...WITH JUST ISOLATED TO WIDELY SCATTERED
SHOWERS AFTER 18Z. THE THREAT OF AN SEVERE WEATHER SHOULD REMAIN
CONFINED TO THE COASTAL PLAIN...WHERE MARGINAL CAPE AND STRONG
SHEAR PHASE THIS AFTERNOON. MODIFIED RAP SOUNDINGS SUGGEST 200-300
J/KG MLCAPE EAST OF I-95 IN THE TRUER WARM SECTOR... WITH 50-60KT
BULK SHEAR. HOWEVER...LOW-LEVEL HODOGRAPHS WILL BECOME MORE LINEAR
WITH TIME AS THE SURFACE WINDS CONTINUE TO VEER TO MORE
SOUTHWESTERLY....SO UNLESS THERE IS LOCAL BACKING IN RESPONSE TO
SOME PERTURBATION WITHIN THE FLOW...IT APPEARS THE CONDITIONAL
TORNADO THREAT WILL BE LIMITED TO THE SOUTHERN COASTAL PLAIN THROUGH
EARLY AFTERNOON.
CHANGES TO THE FORECAST ARE MOSTLY COSMETIC BASED ON TRENDS ON RADAR
AND OBS....WITH THE MAIN ADJUSTMENT TO THE NEAR TERM TEMPS AS
WARMING FROM THE TRIANGLE WESTWARD HAS BEEN A LITTLE SLOWER THAN
FORECAST. LATEST HRRR...WHICH HAS DONE A PRETTY GOOD JOB SO
FAR...SUGGESTS THE WEDGE MAY NOT BREAK IN THE FAR NORTHWEST PIEDMONT
UNTIL THE COLD FRONT ERODES THE AIRMASS LATER TONIGHT. HIGHS
ULTIMATELY END UP RANGING FROM 54-71 NORTHWEST TO SOUTHEAST. -BLS
PRECIP TONIGHT: PRECIPITATION MAY RE-DEVELOP IN THE FORM OF A NARROW
CONVECTIVE LINE LATER THIS EVENING (ROUGHLY 00-06Z) AS THE SFC COLD
FRONT SURGES EASTWARD THROUGH CENTRAL NC. CONFIDENCE IS LOWER THAN
NORMAL WITH REGARD TO THE EVOLUTION OF PRECIPITATION ALONG THE COLD
FRONT THIS EVENING...PARTICULARLY WITH REGARD TO PRE-FRONTAL THERMAL
PROFILES /INSTABILITY/ DUE TO THE WIDE VARIETY OF MECHANISMS AND
POSSIBLE INTERACTIONS DRIVING THE EVOLUTION THEREOF. BASED ON
PREVIOUS EXPERIENCE WITH SIMILAR SETUPS AND THE LATEST MODEL
GUIDANCE...EXPECT THE BEST POTENTIAL FOR ADDITIONAL PRECIPITATION
ALONG AND EAST OF HWY 1 IN THE 01-07Z TIME FRAME. FOR EXAMPLE...THE
HIGH-RES WRF-ARW SUGGESTS DRY CONDITIONS IN THE WESTERN PIEDMONT
WITH A NARROW LINE OF CONVECTION DEVELOPING IN VICINITY OF THE
TRIANGLE AROUND MIDNIGHT...EXITING THE COASTAL PLAIN BY 2-3 AM THU
MORNING.
WHETHER OR NOT CONVECTION WILL ACCOMPANY THE COLD FRONTAL PASSAGE
LATE THIS EVENING INTO TONIGHT ALSO REMAINS UNCLEAR. THE 00Z WRF-ARW
SUGGESTS THAT CONVECTION WILL DEVELOP ALONG THE FRONT AS IT
PROGRESSES FROM THE TRIANGLE INTO THE COASTAL PLAIN BETWEEN 01-07Z.
AN ISOLD SEVERE STORM CAPABLE OF PRODUCING DAMAGING WINDS CANNOT BE
RULED OUT IN THAT TIME FRAME...SHOULD CONVECTION DEVELOP. -VINCENT
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 255 AM WEDNESDAY...
THERE MAY BE A FEW SHOWERS IN THE PROCESS OF EXITING THE FAR EASTERN
ZONES CHRISTMAS MORNING... OTHERWISE EXPECT A WEST TO EAST CLEARING
TRENDING IN THE WAKE OF THE EXITING COLD FRONT.
ADDITIONALLY...DEEPENING SURFACE LOW LIFTING NEWD INTO SE CANADA
WILL RESULT IN BREEZY CONDITIONS ON CHRISTMAS DAY...WITH WEST-
NORTHWESTERLY WINDS GUSTING INTO THE UPPER TEENS TO LOWER
20S...STRONGEST DURING THE FIRST HALF OF THE DAY. WEAK CAA BEHIND
THE FRONT WILL STILL ALLOW FOR SEASONABLY MILD TEMPERATURES. HIGHS
IN THE MID 50S NW TO LOWER 60S SE. LOWS IN THE LOWER TO MID 30S.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 255 AM WEDNESDAY...
SATURDAY NIGHT INTO MONDAY...A PATTERN CHANGE WILL BEGIN TO OCCUR AS
THE UPPER RIDGE OVER THE SE STATES BREAKS DOWN AND A LARGE MID/UPPER
TROUGH DEVELOPS INTO THE WEST-CENTRAL THEN CENTRAL STATES. THE LEAD
COLD FRONT IS EXPECTED TO PUSH INTO NC FROM THE NORTH LATE SUNDAY OR
SUNDAY NIGHT. ALL BETS ARE OFF ON HOW FAR SOUTH THIS INITIAL FRONT
WILL BE ABLE TO SAG INTO NC OR SC. ABOUT HALF THE GFS ENSEMBLE
MEMBERS SUPPORT A STRONG ENOUGH SURFACE HIGH OVER A FAVORED GREAT
LAKES LOCATION TO PUSH THE FRONT INTO SC. THIS IS NOT SUPPORTED BY
THE LATEST OPERATIONAL EC AND HALF THE RELATED ENSEMBLES. THE
STRENGTH OF THE SURFACE WAVE SLATED TO DEVELOP OVER THE LOWER
MISSISSIPPI VALLEY AND THE SUBSEQUENT TRACK (EITHER JUST TO OUR WEST
AND NORTH... OR VERY NEAR OR OVER OUR REGION) IS ALSO CURRENTLY
DEBATABLE. WPC HAS SPLIT THE MIDDLE TAKING THE AVERAGE APPROACH
WHICH WOULD KEEP MOST OF OUR REGION IN THE WARM SECTOR INITIALLY
(UNTIL THE INITIAL WAVE OF LOW PRESSURE PASSES). THIS WOULD ENSURE
ALL RAIN AND MILDER TEMPERATURES THAN IF CAD WERE TO DEVELOP PER
SOME OF THE GFS MEMBERS. FOR NOW... WE WILL TREND A BIT COOLER AND
WETTER... AND TOWARD THE COOLER SOLUTIONS AND GIVE IT A FEW MORE
RUNS BEFORE COMMITTING EITHER WAY. THIS WOULD LEAD TO A CHANCE OF
RAIN LATE SUNDAY INTO MONDAY WITH LOWS IN THE MID 30S TO MID 40S AND
HIGHS IN THE MID 40S TO LOWER 60S N TO SE.
A TURN TO SHARPLY COLDER WEATHER IS EXPECTED BY MID NEXT WEEK WITH
LOWS BACK INTO THE 20S AND HIGHS IN THE 40S.
&&
.AVIATION /18Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1210 PM WEDNESDAY...
PRIMARY AVIATION CONCERNS THIS PERIOD: IFR/LIFR CONDITIONS THROUGH
THIS EVENING... AND LOW LEVEL WIND SHEAR POTENTIAL THROUGH THIS
AFTERNOON.
PERIODS OF POOR AVIATION CONDITIONS WILL DOMINATE THROUGH THIS
EVENING. A WARM FRONT ORIENTED ROUGHLY NE TO SW THROUGH CENTRAL NC
WILL PUSH SLOWLY WNW TODAY THROUGH THIS EVENING... BEFORE A COLD
FRONT SWEEPS IN FROM THE WEST FROM LATE EVENING THROUGH THE
OVERNIGHT HOURS. THE WARM FRONT HAS ALREADY PUSHED WEST OF
FAY/RWI... WHERE SURFACE WINDS ARE MAINLY FROM THE SSW... AND THE
FRONT SHOULD MOVE THROUGH RDU THIS AFTERNOON. AT THESE LOCATIONS
(RDU/FAY/RWI)... VSBYS/CIGS WILL WAVER BETWEEN IFR/LIFR AND MVFR
THROUGH MIDNIGHT... WITH HIGH UNCERTAINTY AS TO WHICH CATEGORY WILL
DOMINATE. AT INT/GSO... THERE IS A GOOD CHANCE THE WARM FRONT WILL
NOT REACH THESE SITES... SO EXPECT THESE IFR/LIFR CONDITIONS TO
DOMINATE NEARLY CONTINUOUSLY THROUGH MID-LATE EVENING. STRONG WINDS
FROM THE SSW AT 30-50 KTS IN THE 800-1600 FT LAYER WILL BRING A RISK
OF LOW LEVEL WIND SHEAR THROUGH THIS AFTERNOON... WITH THE HIGHEST
LLWS POTENTIAL AT RDU WHERE THE VECTOR WIND DIFFERENCE BETWEEN THE
SURFACE AND AROUND 1000 FT AGL WILL BE GREATEST. COLD FRONT PASSAGE
THIS EVENING INTO THE OVERNIGHT HOURS WILL MEAN A RAPID W-TO-E TREND
OF CIGS FROM MAINLY IFR/LIFR TO VFR... MOST LIKELY AT INT/GSO
BETWEEN 02Z AND 04Z AND AT RDU/FAY/RWI BETWEEN 04Z AND 07Z... WITH A
SHIFT OF WINDS TO WSW THEN WNW. VFR CONDITIONS WILL THEN DOMINATE
FROM LATE TONIGHT THROUGH THE END OF THE TAF VALID PERIOD... AS HIGH
PRESSURE BUILDS IN FROM THE SW.
LOOKING BEYOND 18Z THU... VFR CONDITIONS ARE EXPECTED TO HOLD FROM
CHRISTMAS AFTERNOON INTO SUNDAY... ALTHOUGH SOME GROUND FOG IS
POSSIBLE EARLY SAT MORNING AT ALL CENTRAL NC TAF SITES. A STORM
SYSTEM WILL APPROACH FROM THE WEST AND SW ON SUN... BRINGING
INCREASING CHANCES FOR SUB-VFR CONDITIONS AND RAIN FOR LATE SUN
THROUGH MON. -GIH
&&
.HYDROLOGIC DISCUSSION /THROUGH THURSDAY/...
AS OF 210 PM TUESDAY...
THERE HAVE BEEN THREE FAIRLY SIGNIFICANT RAINFALL EVENTS OVER
CENTRAL NORTH CAROLINA DURING THE PAST TWO WEEKS...WITH HEAVIER
RAINFALL AMOUNTS (>1 INCH TOTAL) GENERALLY FROM THE TRIANGLE AND
FAYETTEVILLE AREAS EAST TO THE COAST. AS A RESULT...RELATIVE SOIL
MOISTURE IS UNIFORMLY HIGH THROUGH A 200 CM DEEP COLUMN...WHICH WILL
PROMOTE FASTER RUNOFF AS WELL AS A HIGHER PERCENTAGE OF RAINFALL-TO-
RUNOFF FROM THE UPCOMING EVENT TONIGHT THROUGH CHRISTMAS MORNING.
CURRENT QUANTITATIVE PRECIPITATION FORECASTS RANGE FROM 1.25 INCHES
TO NEARLY 2 INCHES...AND HAVE BEEN TRENDING DOWNWARD WITH SUCCESSIVE
MODEL RUNS. AT THIS TIME...OUR PREFERRED RAINFALL FORECAST IS FOR
WIDESPREAD AMOUNTS OF LESS THAN 1.5 INCHES...WHICH WILL CAUSE
MAINSTEM RIVERS TO RISE SEVERAL FEET FROM CHRISTMAS DAY INTO THE
WEEKEND...BUT RIVER FORECAST POINTS WOULD CREST BELOW MINOR FLOOD
STAGE. WIDESPREAD RAIN NEARER THE HIGH END OF THIS RANGE (1.75 TO
2 INCHES) WOULD LIKELY PRODUCE MINOR FLOODING ON EASTERN RIVERS...
PARTICULARLY THE HAW...NEUSE...AND TAR RIVERS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT/BLS
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...HARTFIELD
HYDROLOGY...BADGETT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1151 AM EST WED DEC 24 2014
.SYNOPSIS...
LOW PRESSURE TO THE WEST OF THE APPALACHIANS WILL DEEPEN AND LIFT
NORTH TOWARD THE GREAT LAKES TODAY. THIS LOW WILL DRAG A COLD FRONT
THROUGH THE COASTAL CAROLINAS TONIGHT. DRY HIGH PRESSURE
WILL BUILD OVER THE SOUTHEAST CHRISTMAS DAY INTO FRIDAY BEFORE
MOVING OFF THE COAST SATURDAY. A COLD FRONT WILL DROP INTO THE
SOUTHEAST ON SUNDAY WITH A FEW WAVES OF LOW PRESSURE DEVELOPING
MONDAY THROUGH WEDNESDAY NEXT WEEK...LEAVING UNSETTLED WEATHER
ACROSS THE CAROLINAS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM WEDNESDAY...COMPLEX AND ACTIVE WEATHER ON TAP FOR MUCH
OF THE SOUTHEAST ON THIS CHRISTMAS EVE.
FULL LATITUDE UPPER TROUGH ALIGNED FROM THE WESTERN GREAT LAKES DOWN
INTO EASTERN TEXAS IS SLOWLY DRIFTING EAST THIS MORNING. BENEATH
THIS TROUGH...A STRENGTHENING SURFACE LOW IS MOVING NORTH INTO THE
GREAT LAKES...AND ALTHOUGH THIS WILL STAY WELL AWAY FROM THE
CWA...IT WILL DRIVE A STRONG COLD FRONT ACROSS THE REGION TONIGHT.
THE COMBINATION OF WAA AHEAD OF THE COLD FRONT...INCREASING THETA-E
RIDGING...AND DIFFLUENCE WITHIN AN UPPER JET WILL CREATE WIDESPREAD
SHOWERS WITH ISOLATED TSTMS TODAY. WHILE PRECIP WILL BE WIDESPREAD
AND HEAVY AT TIMES...TWO BIG QUESTION MARKS STILL REMAIN...AND THESE
ARE WHETHER SEVERE THUNDERSTORMS WILL DEVELOP...AND AT WHAT TIME THE
PRECIP WILL END TODAY.
KLTX IMAGERY THIS MORNING SHOWS AN AREA OF HEAVIER RAINFALL MOVING
ACROSS THE ILM NC COUNTIES...WITH SCATTERED BUT LESS INTENSE SHOWER
ACTIVITY TO THE SOUTHWEST. REGIONAL MOSAIC HAS A LINE OF CONVECTION
FROM WEST OF COLUMBIA, SC...TO VALDOSTA, GA. HIGH RES HRRR AND WRF
SUGGEST A LULL IN PRECIP FOR SEVERAL HOURS THIS AFTN AHEAD OF THE
FORCED LINE...AND HAVE TRIED TO SHOW POP TRENDS MIMICKING THIS IDEA.
THIS SEEMS PLAUSIBLE SINCE DIFFLUENCE THIS MORNING WILL WEAKEN AND
SOME SUBSIDENCE IS LIKELY IN THE WAKE OF THIS MORNINGS ACTION.
HOWEVER...ISOLATED THUNDER WILL STILL BE POSSIBLE THROUGH NOON OR
SO...ESPECIALLY IN PLACES WHERE TEMPS HIT 70-72F SINCE THAT WILL BE
CAPABLE OF TAPPING THE INSTABILITY ABOVE 950MB PRESENT ON THE 12Z
KCHS UA SOUNDING. HEAVY RAIN WILL BE THE PRIMARY THREAT THIS
MORNING...AND SOME PLACES MAY PICK UP A QUICK 1 INCH OF QPF IN
EMBEDDED TSTMS.
THEREAFTER...ATTN TURNS TO THE PRE-FRONTAL FORCED LINE AND ITS
ANTICIPATED IMPACTS LOCALLY. AS THE LOW PRESSURE MOVES NORTH...THE
EASTWARD PROGRESS OF THIS LINE WILL SLOW...AND THEREFORE BELIEVE THE
WRF IS TOO FAST IN ITS EVOLUTION...BUT STILL ACCURATE IN ITS OVERALL
DEPICTION. SPC SWODY1 HAS THE AREA IN A MARGINAL RISK...WITH A
SLIGHT RISK SOUTH OF MYRTLE BEACH...FOR POSSIBLE DAMAGING WINDS AND
ISOLATED TORNADOES AS THIS QLCS APPROACHES. LOCALLY THE TORNADO
THREAT SEEMS EXTREMELY LOW WITH MLCAPES OF 300 J/KG OR LESS AND
0-3KM SRH REACHING ONLY AS HIGH AS AROUND 200 M2/S2. AT THE SAME
TIME...LOW-LEVEL WINDS OF 50 KTS AT 2KFT WILL SLOWLY VEER MORE TO
THE SW THIS AFTN...ERODING EVEN FURTHER THE TORNADO THREAT...BUT
MAINTAINING A DAMAGING WIND POTENTIAL. WILL HAVE TO MONITOR
EVOLUTION OF THIS SQUALL LINE AS IT REACHES THE CWA...AND IT WILL
LIKELY DO SO IN A WEAKENING STATE...BUT CANNOT RULE OUT AN ISOLATED
DAMAGING WIND GUST THIS EVENING. A LARGE AREA OF TRAILING STRATIFORM
RAIN WILL PERSIST BEHIND THE SQUALL LINE...AND THUS EVEN THOUGH THE
COLD FRONT DOES NOT CROSS THE CWA UNTIL AFTER MIDNIGHT...IT WILL
HAVE DIFFICULTY DEVELOPING ANY CONVECTION OTHER THAN SHALLOW SHOWERY
TYPE PRECIP.
HIGHS TODAY WILL RISE INTO THE LOW 70S MOST AREAS EVEN WITHOUT ANY
SUNSHINE THANKS TO STRONG WAA. TEMPERATURES WILL BEGIN TO CRASH
BEHIND THE COLD FRONT AFTER MIDNIGHT...BUT ONLY A FEW HOURS OF
COOLING BEFORE DAYBREAK WILL LIMIT MINS TO AROUND 50 WELL
INLAND...AND NEAR 60 RIGHT ALONG THE COAST.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...A COLD FRONT WILL BE PUSHING FARTHER OFF
SHORE THROUGH THURS AS HIGH PRESSURE BUILDS UP FROM GULF COAST.
ANY LINGERING PCP OR MOISTURE WILL BE SCOURED OUT AS MID TO UPPER
TROUGH MOVES EAST LEAVING A DEEP DRY AND COOLER W-NW FLOW BEHIND
IT. EXPECT PCP WATER VALUES DOWN FROM UP NEAR 2 INCHES THE NIGHT
BEFORE TO A QUARTER OF INCH BY THURS AFTERNOON AS COLUMN DRIES
OUT. OVERALL EXPECT CLEARING SKIES ON CHRISTMAS DAY WITH SUNSHINE
MAKING AN APPEARANCE FOR THE FIRST TIME IN SEVERAL DAYS. TEMPS
SHOULD NOT MOVE MUCH ON THURS AS A WARM START TO THE DAY WILL BE
FOLLOWED BY GUSTY W-NW WINDS BRINGING IN RELATIVELY COOLER AIR.
MODELS HAVE BEEN CONSISTENTLY BACKING OFF ON CAA BEHIND THE FRONT
WITH 850 TEMPS ONLY FALLING ABOUT 6 C BEHIND FRONT BEFORE LEVELING
OFF AND RISING SLIGHTLY THROUGH FRI. TEMPS THURS NIGHT SHOULD BE
DOWN IN THE 30S AND BASICALLY EXPECT SEASONABLE TO ABOVE NORMAL
TEMPS IN THE FORECAST AS HIGH PRESSURE BUILDS UP FROM THE GULF
COAST OVER THE SOUTHEAST THROUGH FRI.
THE CENTER OF THE HIGH ALMOST DIRECTLY OVERHEAD FRI AFTN WILL
SHIFT OFF SHORE BY FRI NIGHT LEAVING A LIGHT RETURN FLOW. THIS
WILL HELP TO CAUSE A SLIGHT RISE IN DEWPOINT TEMPS AND THEREFORE
WILL KEEP TEMP A BIT HIGHER THAN THE NIGHT BEFORE BUT THE WINDS
WILL BE LIGHT ENOUGH UNDER CLEAR SKIES TO PRODUCE DECENT
RADIATIONAL COOLING. THIS WILL BRING TEMPS DOWN CLOSER TO 40 FOR
FRI NIGHT.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 330 AM WEDNESDAY...RIDGE OF HIGH PRESSURE UP THE SOUTHEAST
COAST ON SATURDAY WILL SHIFT EAST THROUGH EARLY NEXT WEEK. THIS
WILL ALLOW A RETURN FLOW TO SET UP WITH SW-W WINDS THROUGH THE
LOW TO MID LEVELS OF THE ATMOSPHERE. INITIALLY SHOULD SEE A FAIR
AMOUNT OF SUNSHINE ON SATURDAY BUT A COLD FRONT WILL DROP SOUTH ON
SUNDAY LEAVING SHALLOW COOL AIR IN PLACE. SHOULD SEE CLOUDS AND
PCP SPREAD OVER THE CAROLINAS SAT NIGHT INTO SUNDAY AS COLD FRONT
DROPS SOUTH WITH SOME DECENT ISENTROPIC LIFT DEVELOPING. THE GFS
AND ECMWF SHOW A FEW WAVES OF LOW PRESSURE MOVING UP FROM THE
GULF COAST ALONG THIS FRONT THROUGH NEXT WEEK. MAY END UP WITH AN
EXTENDED PERIOD OF UNSETTLED WEATHER AS POSSIBLE WEDGE SETS UP.
TEMPS ON SAT INTO SUNDAY SHOULD REMAIN ON THE WARM SIDE WITH 60S
MOST PLACES. SOME UNCERTAINTY EXISTS WITH LOCATION OF COLD FRONT
AS ECMWF KEEPS IT NORTH AND SHOWS WAVES OF LOW PRESSURE MOVING
ALONG FRONT TO THE NORTH OF LOCAL AREA. THIS COULD KEEP LOCAL AREA
IN WARMER SW FLOW AT THE SURFACE WITH WEDGE HOLDING INLAND AND TO
OUR NORTH.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...MODERATE TO HEAVY PRECIP WILL OCCUR THROUGH MUCH OF THE
AFTERNOON WITH ISOLATED THUNDER. THE COASTAL TERMINALS ARE BOUNCING
FROM IFR TO MVFR WITH STRONG SOUTH SOUTHWESTERLY FLOW. MODELS ARE IN
REASONABLE AGREEMENT WITH THE HEAVIEST ACTIVITY THIS
AFTERNOON...FOLLOWED BY LIGHTER PRECIP ALONG THE FRONT THIS EVENING.
THE FRONT WILL REACH THE COAST THROUGH THE OVERNIGHT HOURS. LOOK FOR
A WIND SHIFT TO THE WEST...POST FRONTAL. SKIES SHOULD IMPROVE FAIRLY
RAPIDLY TO VFR BEHIND THE FRONT WITH GUSTY WEST WINDS DIMINISHING
SOMEWHAT SHORTLY AFTER DAYBREAK.
EXTENDED OUTLOOK...VFR THURSDAY THROUGH SATURDAY. RAIN RETURNING
SUNDAY AND POSSIBLY MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM WEDNESDAY...TROPICAL AIRMASS BEHIND A WARM FRONT NOW
SITUATED WELL INLAND IS ADVECTING INTO THE WATERS THIS
MORNING...WITH DEWPOINT TEMPERATURES APPROACHING 70...OR EVEN THE
LOW 70S. THESE DEWPOINT TEMPS ARE 15 DEGREES ABOVE THE COOL SHELF
WATER TEMPS...WHICH IS TYPICALLY A SIGNAL FOR SEA FOG. ATTM
HOWEVER...NO VSBY RESTRICTIONS HAVE BEEN NOTED AND IT MAY BE SIMPLY
DUE TO THE STRENGTH OF THE WIND FIELDS NOT ALLOWING FOR AMPLE PARCEL
RESIDENCE TIME. STILL...THE MARINE DENSE FOG ADVISORY REMAINS AND
WILL CONTINUE AS THERE REDUCED VISIBILITY IN MARINE FOG IS STILL
EXPECTED TO DEVELOP UNTIL THE COLD FRONTAL PASSAGE TONIGHT.
SHOWER ACTIVITY WILL BE SCATTERED THROUGH THE AFTN AND EVE...BEFORE
A MORE STRONGLY FORCED SQUALL LINE WILL CROSS THE WATERS THIS
EVENING AND TONIGHT. WINDS WILL BE GUSTY TODAY EVEN OUTSIDE OF
CONVECTION...AND THE CURRENT SCA REMAINS UNCHANGED FOR BOTH WINDS
AND SEAS...WHICH ARE ALREADY APPROACHING 7 FT AT WILMINGTON HARBOR
BUOY. A WIND SHIFT TO THE WEST WILL OCCUR WITH THE FROPA...WHICH IS
EXPECTED AFTER MIDNIGHT.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...COLD FRONT WILL SHIFT FARTHER OFF SHORE ON
THURS AS HIGH PRESSURE BUILDS UP FROM THE GULF COAST. GUSTY W-SW
WINDS EARLY THURS WILL VEER AROUND BECOMING WEST THROUGH THE DAY.
SEAS UP AROUND 5 TO 7 FT SHOULD FALL BELOW SCA THRESHOLDS BY THURS
AFTN WITH HIGHEST SEAS GETTING PUSHED FARTHER OFF SHORE IN STRONGER
W-NW FLOW BEHIND FRONT. WINDS WILL VEER FURTHER TO THE NW AND
LIGHTEN UP LATE THURS INTO FRI AS CENTER OF HIGH SHIFTS CLOSER
OVERHEAD. SEAS WILL BE DOWN TO 2 TO 4 FT BY THURS NIGHT AND DOWN TO
3 FT OR LESS THROUGH FRI AS HIGH PRESSURE MOVES OVERHEAD WITH MORE
VARIABLE WINDS EXPECTED.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 330 AM WEDNESDAY...HIGH PRESSURE WILL SHIFT FARTHER OFF
SHORE ON SATURDAY WITH A RETURN FLOW S-SW 10 KTS OR LESS SETTING
UP. A COLD FRONT WILL DROP SOUTH SUN WITH POSSIBLE WEDGE
DEVELOPING WITH WINDS VEERING AROUND TO THE N-NE AS IT DROPS SOUTH
SUN NIGHT. THIS WILL PUSH SEAS UP A BIT BUT OVERALL BUT EXPECT
SEAS TO GENERALLY 3 FT OR LESS THROUGH THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 6 PM EST THIS EVENING FOR AMZ250-252-
254-256.
SMALL CRAFT ADVISORY UNTIL NOON EST THURSDAY FOR AMZ250-252-
254-256.
&&
$$
NEAR TERM...17
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...43
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1210 PM CST WED DEC 24 2014
.UPDATE...
ISSUED AT 1206 PM CST WED DEC 24 2014
REGIONAL RADAR MOSAIC CONTINUES TO SHOW LIGHT RETURNS ACROSS PARTS
OF NORTH DAKOTA INTO WESTERN MONTANA. MUCH OF THE PRECIPITATION
HAS NOT BEEN REACHING THE GROUND DUE TO DRY AIR IN THE LOW AND MID
LEVELS. WILL CONTINUE TO CARRY A SMALL CHANCE OF SNOW / RAIN THIS
AFTERNOON...WITH THE RAIN CHANCES MAINLY IN THE SOUTHWEST WHERE
H85 TEMPERATURES HAVE WARMED ABOVE ZERO DEGREES CELSIUS.
LOOKING AT TONIGHT INTO CHRISTMAS DAY...MODELS STILL SUPPORT LIGHT
SNOW ACCUMULATIONS ACROSS THE SOUTHWEST AND FAR SOUTHERN PART OF
THE STATE. THE LATEST WPC GUIDANCE PLACES AN INCH OR TWO IN THE
SOUTHWEST...WHICH IS IN LINE WITH THE GOING FORECAST.
UPDATE ISSUED AT 945 AM CST WED DEC 24 2014
UPDATE HAS BEEN ISSUED. OBSERVATIONS SHOW FOG CONTINUES IN PARTS
OF CENTRAL NORTH DAKOTA...SO EXTENDED PATCHY FOG FOR THE REMAINDER
OF THE MORNING HOURS. EARLY MORNING RADAR MOSAIC SHOWS WEAK ECHOES
MOVING ACROSS PARTS OF WESTERN AND CENTRAL NORTH DAKOTA...BUT
LITTLE TO NO PRECIPITATION HAS BEEN REACHING THE GROUND. A DRY
LAYER IS APPARENT FROM THE 24.12Z BISMARCK SOUNDING WHICH HAS BEEN
INHIBITING THE PRECIPITATION. THINK THE CURRENT SMALL POPS COVER
THIS SCENARIO. DEBATED THE POTENTIAL FOR A BRIEF PERIOD OF VERY
LIGHT FREEZING RAIN / SPRINKLES IN THE SOUTHWEST WHERE WARMER AIR
ALOFT HAS ARRIVED. DECIDED TO ADD IT INTO THE FORECAST FOR JUST A
COUPLE HOURS UNTIL SURFACE TEMPERATURES RISE ABOVE FREEZING.
UPDATE ISSUED AT 637 AM CST WED DEC 24 2014
THE MAIN CHANGE WITH THIS UPDATE WAS TO ADJUST HOURLY FORECAST TEMPS
TO MATCH OBSERVED VALUES IN CENTRAL AND EASTERN LOCATIONS WHERE
TEMPS WERE RUNNING ABOVE FORECAST VALUES DUE TO CLOUD COVER. THE
SAME AREA HAS NUMEROUS REPORTS OF FOG...THOUGH NO SIGNIFICANT
REDUCTIONS IN VISIBILITY AT THIS TIME...GENERALLY 3-5SM VIS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 339 AM CST WED DEC 24 2014
THE MAIN CONCERN IN THE SHORT WILL BE FOG THIS MORNING...THEN
ATTENTION TURNS TO CHANCES OF PRECIPITATION...WITH AND WEATHER TYPE
DURING THE DAY.
CURRENTLY...A WEAK SURFACE RIDGE AXIS EXTENDED ACROSS EASTERN NORTH
DAKOTA - BETWEEN A STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES
AREA AND DEVELOPING LOW PRESSURE IN THE LEE OF THE ROCKIES. ALONG
AND EAST OF THIS RIDGE IS A LARGE STRATUS CLOUD FIELD EXTENDING FROM
THE EASTERN DAKOTAS TO THE GREAT LAKES. IN THE WESTERN DAKOTAS
CIRRUS CLOUDS COVERED MOST OF THE AREA...WITH PATCHY/OCCASIONAL FOG
REPORTED...SOMETIMES LIGHT FOG AND SOMETIMES VISIBILITIES DROP DOWN
TO 1/2 MILE OR LESS FOR SHORT PERIODS.
THE VARIOUS RUNS OF THE HRRR MODEL HAVE SUGGESTED THAT THE WESTERN
EDGE OF THE STRATUS DECK SHOULD ERODE WITH TIME...WITH PATCHY AREAS
OF DENSE FOG FORMING IN THE IMMEDIATE CLEARING OF THE STRATUS.
HOWEVER THE MODEL SUGGESTS THE DENSE FOG NOT LASTING/LINGERING IN
ANY ONE AREA. MEANWHILE INCREASING MID LEVEL CLOUDS MOVING IN FROM
EASTERN MONTANA SHOULD EVENTUALLY LIMIT ANY FOG FORMATION. THUS WILL
KEEP A MENTION OF PATCHY FOG OVER THE WESTERN HALF OF THE STATE
THROUGH AROUND 6 AM...THEN CONTINUE THE PATCHY FOG MENTION OVER ALL
OF CENTRAL NORTH DAKOTA UNTIL AROUND 9 AM.
THE NEXT WEATHER SYSTEM TO AFFECT NORTH DAKOTA IS OVER THE WESTERN
COAST OF NORTH AMERICA EARLY THIS MORNING. BROAD ZONAL FLOW WAS OVER
THE NORTHERN PLAINS AHEAD OF THE SYSTEM WITH LOW PRESSURE IN NORTH
CENTRAL CANADA. THE ZONAL FLOW CONTAINS SOME UPPER LEVEL IMPULSE
ENERGY THAT WAS ASSOCIATED WITH A MID-LEVEL DECK OF CLOUDS OVER
SASKATCHEWAN/MONTANA MOVING EASTWARD...WITH SOME LIGHT RADAR RETURNS
SEEN ON THE RADAR MOSAIC. SURFACE LOW PRESSURE IN THE LEE OF THE
ROCKIES THIS MORNING WILL MOVE EAST ACROSS THE DAKOTAS TODAY. WARM
ADVECTION AHEAD/ALONG THE SYSTEM WAS MOVING INTO WESTERN NORTH
DAKOTA THIS MORNING. THERE IS A SLIGHT CHANCE OF LIGHT PRECIPITATION
WITH THIS UPPER LEVEL ENERGY AS IT MOVES EAST ACROSS THE REGION. THE
MAIN QUESTION IS WHETHER FREEZING RAIN WILL BE AN ISSUE THIS
MORNING. THE APPROACH OF THE MID CLOUD DECK WILL MEAN THAT ICE
CRYSTALS WILL BE LIKELY AT MID AND UPPER LEVELS. SHOULD ANY OF THESE
ICE CRYSTALS FALL INTO LOWER LAYERS OF THE ATMOSPHERE...PROGGED
MODEL SOUNDINGS SUGGEST THAT INITIALLY THERE IS A WARM
LAYER/INVERSION - BUT THAT THE FROST POINT WITHIN THIS LAYER IS MUCH
COOLER THAN THE DRY BULB TEMPERATURE. THUS PARTICLES FALLING THROUGH
SHOULD COOL TOWARDS THE FROST POINT AND REMAIN COOL ENOUGH FOR ALL
SNOW. LATER IN THE DAY AS SURFACE TEMPERATURES WARM ABOVE FREEZING -
MAINLY IN THE WEST - PRECIPITATION WOULD CHANGE TO RAIN.
TONIGHT THE COLD FRONT PORTION OF THE WEATHER SYSTEM WILL MOVE
SOUTHEAST ACROSS THE STATE. AS THIS OCCURS...THE UPPER LEVEL FLOW
BECOMES MORE SOUTHWESTERLY ACROSS THE DAKOTAS - AND THE LEADING EDGE
OF A SERIES OF UPPER LEVEL ENERGY IMPULSES AND MID LEVEL MOISTURE
ARRIVES. BY THIS TIME ANY PRECIPITATION THAT FALLS SHOULD BE IN THE
FORM OF SNOW...OR AT LEAST CHANGING OVER FROM RAIN TO SNOW. MOST OF
THE SNOW SHOULD OCCUR OVER MONTANA AND NORTHERN WYOMING...WITH
SOUTHWESTERN NORTH DAKOTA AND NORTHWESTERN SOUTH DAKOTA RECEIVING
SOME LIGHT SNOW BY CHRISTMAS MORNING. ESTIMATES ARE THAT BY
CHRISTMAS MORNING SNOW AMOUNTS OF AROUND 1/2 INCH WOULD BE COMMON IN
THE SOUTHWEST...MAINLY FROM BEACH TO DICKINSON TO HETTINGER AND
POINTS SOUTH AND WEST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 339 AM CST WED DEC 24 2014
MAIN FORECAST CHALLENGES INVOLVE LIGHT SNOW ACROSS SOUTHERN NORTH
DAKOTA CHRISTMAS DAY AND MUCH COLDER WEATHER BY FRIDAY AND
CONTINUING INTO NEXT WEEK. LATEST 00Z DETERMINISTIC MODELS AS WELL
AS SREF ARE IN GOOD AGREEMENT WITH KEEPING MEASURABLE PRECIP IN THE
FORM OF SNOW ALONG AND SOUTH OF THE ND/SD BORDER ON CHRISTMAS DAY.
THIS INCLUDES THE 00Z NAM WHICH HAS COME BACK IN LINE WITH OTHER
MODEL GUIDANCE WITH A MORE SOUTHWARD LOCATION OF SNOW. MAY SEE
AROUND AN INCH OF SNOW ACCUMULATION CLOSE TO THE STATE BORDER.
WHILE THE SURFACE LOW RESPONSIBLE FOR THIS SNOW MOVES NORTHEAST FROM
THE CENTRAL PLAINS TO THE GREAT LAKES REGION THURSDAY/FRIDAY...
NORTHERLY WINDS WILL ADVECT ARCTIC AIR ACROSS THE NORTHERN PLAINS.
HIGH TEMPS WILL BE IN THE TEENS AND 20S FRIDAY THROUGH THE WEEKEND
BEFORE A STRONGER ARCTIC FRONT PUSHES ACROSS THE REGION EARLY
SUNDAY. SOME DIFFERENCES IN HEIGHT FIELDS DEVELOP BETWEEN
GFS/ECMWF EARLY NEXT WEEK ALTHOUGH BOTH ARE IN AGREEMENT WITH
EXTENSIVE LONG WAVE TROUGH APPROXIMATELY FROM HUDSON BAY TO
INTERMOUNTAIN WEST. GFS HAS -30C CORE AT 850MB OVER NORTHEAST ND
ON TUESDAY WITH THE ECMWF SLIGHTLY WARMER. REGARDLESS...VERY COLD
CONDITIONS EXPECTED WITH WIND CHILLS REACHING DANGEROUS LEVELS
UNDER NORTHWEST FLOW MONDAY NIGHT AND TUESDAY NIGHT WITH 1050MB
SURFACE HIGH SETTING UP OVER WESTERN MONTANA. MAJORITY OF THE CWA
CURRENTLY LOOKS TO REACH WIND CHILL ADVISORY CRITERIA FOR THESE
TIME PERIODS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1206 PM CST WED DEC 24 2014
MANY LOCATIONS ACROSS WESTERN AND CENTRAL NORTH DAKOTA HAVE SEEN
CEILINGS IMPROVE TO VFR...WITH MVFR AND IFR BECOMING LESS
PRONOUNCED. KJMS IS STILL REPORTING IFR CEILINGS...BUT EXPECT
THOSE TO SLOWLY IMPROVE THIS AFTERNOON. A CHANCE OF LIGHT SNOW
WILL INCREASE TONIGHT...MAINLY FOR KDIK AS LOW PRESSURE GATHERS IN
SOUTHWEST SOUTH DAKOTA. COULD ALSO SEE MVFR CEILINGS LATER TONIGHT
AT THE REMAINDER OF THE AERODROMES...KISN..KMOT...KBIS AND KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...JV
LONG TERM...JNS
AVIATION...CK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1225 PM EST WED DEC 24 2014
.SYNOPSIS...
LOW PRESSURE WILL MOVE NORTH OUT OF THE TENNESSEE VALLEY TODAY TO
OHIO AND LAKE ERIE BY THIS EVENING. A TRAILING COLD FRONT WILL SWEEP
EAST ACROSS THE REGION THIS EVENING. STRONG GUSTY WINDS ARE EXPECTED
WITH THIS STORM SYSTEM ACROSS THE AREA. A RIDGE OF HIGH PRESSURE
WILL BUILD NORTH INTO THE REGION BY THURSDAY EVENING. LOW PRESSURE
WILL BUILD NORTHEAST INTO THE NORTHERN LAKES BY SATURDAY FOLLOWED BY
ANOTHER COLD FRONT SATURDAY NIGHT INTO SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ONLY MADE MINOR CHANGES TO THE FORECAST AT THIS TIME.
STRONG 5H JET MOVING UP THE OHIO RIVER VALLEY THIS MORNING. THE
LOW PRESSURE THAT IS OVER SOUTHERN INDIANA WILL CONTINUE TO DEEPEN
AS IT LIFTS NORTH-NORTHEAST THROUGH THE AFTERNOON. AT THIS POINT
THE BETTER LIFT ON THE LEFT FRONT QUAD OF THE JET HAS KEPT MOST OF
THE SHOWERS OVER INDIANA. IT STILL APPEARS THERE WILL BE A LINE OF
LOW TOPPED SHOWERS/THUNDERSTORMS THAT WILL RACE ACROSS THE AREA
NEAR THE COLD FRONT LATE THIS AFTERNOON INTO THE EVENING.
WE WILL CONTINUE TO MONITOR THE LOCATION OF THE LOW LEVEL JET
THAT SHOULD INCREASE THROUGH THE AFTERNOON AS IT LIFTS NORTHWARD
ACROSS CENTRAL OHIO. THE CORE OF THE LOW LEVEL JET LOOKS AS IF IT
WILL BE SLIGHTLY FURTHER EAST THAN PREVIOUS THINKING. WE WILL DIG
INTO THE NEW MODEL RUNS AS THEY ARRIVE AND TWEAK THE WIND
ADVISORY/WARNINGS IF NEEDED.
PREVIOUS DISCUSSION...
THE STORM SYSTEM THAT HAS BEEN ADVERTISED FOR THE LAST WEEK HAS
FINALLY ARRIVED. THE STORM SYSTEM IS PROGGED TO MOVE NORTH OUT OF
THE TENNESSEE VALLEY AREA INTO WESTERN OHIO AND WESTERN LAKE ERIE BY
THIS EVENING. THE MAIN PROBLEM WITH THE SYSTEM WILL BE THE STRONG
DAMAGING WINDS ASSOCIATED WITH THE SYSTEM. STRONG LOW LEVEL JET AND
PRESSURE RISE/FALL COUPLET ALONG THE COLD FRONT WILL ALLOW SOME OF
THE STRONGER WINDS ALOFT TO REACH THE SURFACE. THE WINDOW FOR THE
STRONG WINDS APPEARS THAT IT WILL BE A FAIRLY NARROW TIME FRAME FROM
LATE THIS AFTERNOON THROUGH THURSDAY MORNING. WINDS OF 20 TO 35 MPH
WITH GUSTS AS HIGH AS 60 MPH ARE EXPECTED IN THE WESTERN PORTIONS OF
THE FORECAST AREA AND ALONG THE NORTHEAST LAKE SHORE. SLIGHTLY LOWER
WINDS AND WIND GUSTS ARE EXPECTED ELSEWHERE. THEREFORE...A HIGH
WIND WARNING HAS BEEN ISSUED FOR THE WEST HALF AND IMMEDIATE LAKE
SHORE IN THE NORTHEAST. A WIND ADVISORY HAS BEEN ISSUED FOR THE
REST OF THE EASTERN AREAS.
NEXT PROBLEM IS HOW MUCH RAIN ARE WE GOING TO DEAL WITH. SOME
INDICATIONS ARE THAT THE SHOWERS MAY HOLD OFF UNTIL THIS EVENING
OVER MUCH OF THE AREA. HOWEVER...LATEST RADAR AND HRRR MODEL SUGGEST
SOME SCATTERED SHOWER ACTIVITY THROUGH THE DAY. STORM SYSTEM AND
COLD FRONT SHOULD BRING ANOTHER SWATH OF MOISTURE INTO THE REGION
THIS MORNING AND AGAIN THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
OVERALL UPPER LEVEL PATTERN IS PROGRESSIVE AND FAST MOVING. UPPER
LEVEL TROUGH THAT GENERATED THE CURRENT STORM SYSTEM WILL QUICKLY
CAUSE SURFACE LOW PRESSURE SYSTEM TO QUICKLY VACATE THE AREA ON
THURSDAY. ACTUALLY...SOME WARM AIR ADVECTION IS EXPECTED TO DEVELOP
LATER IN THE DAY ON THURSDAY. THIS SHOULD HELP TO BOOST THE
TEMPERATURES POSSIBLY BACK TO THE LOWER 40S.
SYNOPTIC PRECIPITATION FOR THE MOST PART IS EXPECTED TO PULL OUT TO
THE NORTHEAST FAIRLY QUICKLY WITH THE STORM SYSTEM ON THURSDAY. SOME
LINGERING LAKE EFFECT RAIN/SNOW SHOWERS IS POSSIBLE THURSDAY BEFORE
ENDING.
NEXT STORM SYSTEM APPROACHES THE AREA AND IT WILL MAKE ITS PRESENCE
KNOWN FAIRLY QUICKLY AS EARLY AS SATURDAY. A STORM SYSTEM WILL MOVE
EAST INTO THE WESTERN GREAT LAKES AND DRAG A COLD FRONT ACROSS THE
REGION BY SATURDAY NIGHT. MILD TEMPERATURES SHOULD KEEP
PRECIPITATION IN THE FORM OF RAIN THROUGH THE PERIOD. NOT EXPECTING
ANY MAJOR COOL DOWNS THROUGH MUCH OF THE UPCOMING LAST WEEK OF THE
NEW YEAR. HOWEVER...MODELS ARE HINTING AT A FAIRLY MAJOR COLD AIR
OUT BREAK JUST IN TIME FOR THE NEW YEAR TO ARRIVE. SO FAR THIS LOOKS
TO BE COLDEST AIR OF THE SEASON. DEPENDING ON WHICH MODEL YOU LOOK
AT...THE COLD AIR TAKES A GLANCING BLOW WHILE THE OTHER MODEL SLOWS
THE COLD AIR EXITING OUR AREA.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THE EXTENDED IS NOT CLEAR CUT. ON SUNDAY THE THREAT OF SNOW SHOWERS
WILL BE ENDING FROM THE NORTH AS HIGH PRESSURE BUILDS IN. THE ECMWF
IS SLOWER WITH THE PRECIPITATION DECREASE AND WARMER TO START. AT
THIS TIME KEPT THE THREAT JUST SNOW SHOWERS BUT THIS WILL HAVE TO BE
WATCHED. LATE MONDAY INTO TUESDAY THE MODELS BRING A LOW UP INTO THE
OHIO VALLEY. THE POPS MAY HAVE TO BE RAISED IF THE MODELS KEEP
SHOWING THIS TREND. WENT CLOSE TO WPC GUIDANCE FOR THE TEMPERATURE
FORECAST.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
A STRONG AND DEEPENING LOW MOVES ALONG THE OHIO AND INDIANA
BORDER THIS AFTERNOON AND EVENING....LOOK FOR MOSTLY MVFR
CONDITIONS THIS AFTERNOON AND EVENING.
THE FRONT ASSOCIATED WITH THE LOW SWEEPS ACROSS THE AREA LATE
THIS EVENING. SOME SHOWERS AND ISOLATED THUNDERSTORMS COULD
ACCOMPANY THE FRONT...FOR SOME OF THE TAFS...I MENTIONED VCTS
FOR KMFD...KCAK AND KYNG AT THIS TIME.
SOME STRONG WINDS WILL OCCUR WITH THE FRONTAL PASSAGE AND THEN
WINDS WILL GUST TO 40 TO 45 KNOTS BEHIND THE FRONT FOR A FEW HOURS
WITH ISOLATED GUSTS TO 50 KNOTS WILL ALSO BE POSSIBLE. A DRY SLOT
WILL OCCUR AFTER THE FRONTAL PASSAGE AND THEN A NARROW BAND OF
MAINLY SNOW SHOWERS WILL OCCUR LATE TONIGHT. AT THIS TIME IT SEEMS
LIKELY IT WILL BE COLD ENOUGH FOR JUST SNOW TOWARDS MORNING. THE
VISIBILITY MAY DROP LOWER THEN 3SM FOR A BRIEF TIME.
.OUTLOOK...NON-VFR LIKELY THURSDAY. NON-VFR DEVELOPING AGAIN
SATURDAY AND CONTINUING SUNDAY.
&&
.MARINE...
WINDS WILL BE ON THE INCREASE ON THE LAKE ESPECIALLY THIS AFTERNOON
AFTER THE LOW MOVES NORTH AND THE COLD FRONT MOVES THROUGH. SOME
QUESTION ON THE EXACT TIMING OF WHEN THE GALE FORCE WINDS WILL
START. WILL HAVE THE GALE WARNING START ON THE WEST END AT 22Z AND
ON THE EAST END AT 02Z. WE ALSO COULD HAVE A SQUALL LINE MOVE
THROUGH LATE THIS AFTERNOON AND EVENING WITH HIGH WINDS. THE LOW
MOVES QUICK SO THIS WILL BE A QUICK SHOT OF GALE FORCE WINDS. SOME
CONCERN WITH THE 925 MB WINDS ON THE LAKE OVER 50 KNOTS...THE COLD
ADVECTION IS SOMEWHAT GRADUAL SO GOING WITH SUSTAINED OF 40 TO 45
KNOTS WITH HIGHER GUSTS. BECAUSE OF THE GALE FORCE WINDS THE WATER
LEVEL WILL DROP ON THE WEST END OF THE LAKE LATE THIS EVENING...A
LOW WATER ADVISORY WILL BE ISSUED. ONCE THE GALE DECREASE LATE
THURSDAY A SMALL CRAFT ADVISORY WILL BE NEEDED ON THE EAST END.
A MODERATE SOUTHWEST FLOW WILL CONTINUE ON THE LAKE FOR FRIDAY AND
SATURDAY. IT IS IN WARM ADVECTION SO WE MAY NOT NEED A SMALL CRAFT
ADVISORY ON THE LAKE. A COLD FRONT MOVES THROUGH LATE SATURDAY AND
WE MAY NEED A SMALL CRAFT ADVISORY ON THE EAST END OF THE LAKE IN
THE COLD ADVECTION. IT WILL BE SHORT LIVED AS HIGH PRESSURE BUILDS
IN QUICKLY ON SUNDAY. FOR EARLY NEXT WEEK THE FLOW ON THE LAKE WILL
BE EAST AND LIGHT AND LOW PRESSURE MOVES THROUGH THE OHIO VALLEY AND
HIGH PRESSURE IS OVER CANADA.
&&
.CLIMATE...
TEMPERATURES TODAY WILL ATTEMPT TO SURGE INTO THE 60S AND MAY
APPROACH RECORD LEVELS. THE CURRENT RECORDS ARE:
CLEVELAND 65 1964 AKRON-CANTON 63 1964
ERIE 66 1964 MANSFIELD 62 1964
TOLEDO 65 1889 YOUNGSTOWN 63 1982
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...HIGH WIND WARNING FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY
FOR OHZ012-089.
WIND ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY FOR
OHZ013-014-021>023-031>033-038.
HIGH WIND WARNING UNTIL 4 AM EST THURSDAY FOR OHZ003-006>011-
017>020-027>030-036-037-047.
PA...HIGH WIND WARNING FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY
FOR PAZ001.
WIND ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY FOR
PAZ002-003.
MARINE...GALE WARNING FROM 9 PM THIS EVENING TO 4 PM EST THURSDAY FOR
LEZ061-145>149-165>169.
LOW WATER ADVISORY FROM 9 PM THIS EVENING TO NOON EST THURSDAY
FOR LEZ142>144-162>164.
GALE WARNING FROM 5 PM THIS AFTERNOON TO 10 AM EST THURSDAY
FOR LEZ142>144-162>164.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY/MULLEN
SHORT TERM...LOMBARDY
LONG TERM...KIELTYKA
AVIATION...BC
MARINE...KIELTYKA
CLIMATE...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
515 PM EST WED DEC 24 2014
.SYNOPSIS...
AN INTENSIFYING STORM SYSTEM OVER WESTERN OHIO WILL MOVE UP
THROUGH THE EASTERN GREAT LAKES THIS EVENING...DRAGGING A COLD
FRONT THROUGH THE REGION OVERNIGHT. GUSTY WEST WINDS WILL DEVELOP
BEHIND THE FRONT LATE TONIGHT AND THURSDAY. ANOTHER LESS POTENT
COLD FRONT WILL MOVE ACROSS THE AREA THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
REGIONAL RADAR SHOWS A LARGE-DISORGANIZED SHIELD OF RAIN
EXTENDING ALL WAY DOWN INTO THE CAROLINAS. THE MAIN THRUST REMAINS
OFF TO THE NORTHEAST WITH THE LATEST HRRR SUGGESTING THE BEST
CHANCES FOR RAIN INTO THE EVENING BEING FROM CENTRAL PA
EASTWARD...WITH MORE IN THE WAY OF A SPOTTY LIGHT RAIN OR SHOWERS
EXPECTED OVER MY WESTERN ZONES. NOT MUCH REASON TO EXPECT OTHER
THAN A CONTINUATION OF A DREARY CHRISTMAS EVE WITH PERIODS OF RAIN
AND AREAS OF FOG.
THE COLD FRONT SHOULD BE ENTERING MY WESTERN ZONES BETWEEN ABOUT 6
AND 9 PM...AND THEN IS EXPECTED TO SPEED ACROSS THE FORECAST AREA
TO BE EXITING MY FAR EASTERN ZONES BY THE PRE DAWN HOURS OF
CHRISTMAS MORNING. THE FRONT WILL BE ACCOMPANIED BY SOME
MARGINALLY STEEP MID LEVEL LAPSE RATES WHICH COULD LEAD TO A
RUMBLE OR TWO OF THUNDER ACCOMPANYING THE SYSTEM AS IT RACES
THROUGH. EARLIER EXPECTATIONS OF SOME SORT OF NARROW COLD FRONTAL
RAIN BAND-SQUALL LINE FEATURE IS BEING DOWNPLAYED IN THE LATEST
HIGH RES MODEL GUIDANCE WHICH SHOWS A GENERAL AREA OF SHOWERS
MOVING ACROSS THE REGION THIS EVENING ALONG AND AHEAD OF THE
FRONT. THIS SHOULD DIMINISH THE THREAT OF STRONG WINDS ALOFT
BEING TRANSFERRED DOWN IN THE CONVECTION.
TEMPS WILL STAY STEADY OR EVEN CLIMB AS THE FRONT ENTERS THE
REGION THIS EVENING HELPING MIX UP THE COOL AIR DAMMED BOUNDARY
LAYER.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
CHRISTMAS DAY WILL BRING A TRANSITION INTO A PRETTY TYPICAL POST
FRONTAL COOL SEASON PATTERN...WITH CLOUDS AND BLUSTERY GUSTY
WESTERLY WINDS. HIGHER ELEVATIONS WILL LIKELY SEE WINDS AS HIGH AS
35-45 MPH...WITH THE REST OF US MAINLY EXPERIENCING WINDS IN THE
20-30 MPH RANGE.
THE USUAL SCATTERED MAINLY HIGHER ELEVATION SNOW SHOWERS WILL BE
THE FEATURED CONDITIONS...WITH THE CENTRAL RIDGE-VALLEY REGION
SEEING LITTLE MORE THAN A PASSING LIGHT RAIN OR SNOW SHOWER. THE
POST FRONTAL AIR IS NOT REALLY VERY COLD SO EVEN WHERE THE MAIN
PRECIPITATION TYPE IS EXPECTED TO BE SNOW...TEMPERATURES ABOVE
FREEZING WILL KEEP ANY ACCUMULATIONS ON THE INSIGNIFICANT SIDE.
TEMPS WILL BE STEADY OR SLOWLY FALLING FOR MUCH OF THE DAY
THURSDAY...AFTER THE INITIAL DROP OF 10F OR SO IMMEDIATELY
FOLLOWING THE CFROPA VERY EARLY ON.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
POTENT LONGWAVE UPPER TROF EXITING THE EAST COAST AT THE START OF
THE PERIOD WILL BE REPLACED BY UPPER RIDGING INTO THE WEEKEND. AS
LONGWAVE UPPER TROFFING IS FORECAST TO DEVELOP OVER THE WRN US
STARTING EARLY IN THE PD AND NRN STREAM ENERGY RETREATS INTO
EASTERN CANADA...MDT TO STRONG SWRLY FLOW ALOFT IS THEN FORECAST
TO DOMINATE THE EASTERN CONUS FROM LATE IN THE WEEKEND THROUGH THE
REMAINDER OF THE YEAR.
MEDIUM RANGE GUIDANCE IS FAIRLY CONSISTENT ESPECIALLY EARLY IN
THE PERIOD...BUT THEN SOME DIFFERENCES ARISE IN 500MB FLOW
PATTERN AFTER MONDAY AS THE ECMWF MOVES ENERGY EAST FASTER...WHILE
THE GFS CLOSES OFF AN UPPER LOW OVER THE DESERT SW.
A NORTHERN STREAM WAVE IS FORECAST TO SUPPORT A COLD FRONT MOVING
EAST ACROSS THE STATE LATE IN THE WEEKEND...POSSIBLY STALLING
NEAR THE MASON DIXON LINE INTO MONDAY AS IT ENCOUNTERS RESISTANCE
FROM THE BUILDING UPPER FLOW. THIS FRONT LOOKS TO BE THE MAIN
FOCUS FOR PCPN IN THE LONG TERM PERIOD. WITH SNOW TO THE NORTH AND
WEST...AND A MIX TO RAIN ACROSS THE SOUTH.
WITH RIDGING OR SWRLY FLOW ALOFT MUCH OF THE PERIOD WILL FEATURE
ABOVE NORMAL TEMPS...WITH A COOL DOWN TOWARD NORMAL BY NEW YEARS
EVE.
&&
.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
THE MAIN CONCERNS REMAIN LIFR TO MVFR CONDITIONS AND LLWS
THIS EVENING.
HOWEVER...WATCHING LINE OF STORMS WEST OF PA. SINCE WE ARE
AT LEAST 10 DEGREES COOLER AND DEWPOINTS LOWER...THINK ANY
REAL STRONG STORMS WILL WEAKEN AS THEY MOVE TOWARD CENTRAL
PA. WILL CONTINUE TO MONITOR.
21Z TAFS SENT.
EARLIER DISCUSSION BELOW.
WIDESPREAD MVFR/IFR WITH RAIN AND AREAS OF FOG WILL CONTINUE
INTO THE EVENING AS A STORM SYSTEM MOVES INTO THE EASTERN GREAT
LAKES THIS EVENING.
THE ASSOCIATED TRAILING COLD FRONT WILL PUSH THROUGH CENTRAL
PENNSYLVANIA TONIGHT. ISOLATED EMBEDDED THUNDERSTORMS CANNOT BE
RULED OUT ALONG THE FRONT. STRONG AND GUSTY WEST WINDS WILL
DEVELOP BEHIND THE FRONT TONIGHT AND THURSDAY.
INCLUDED LLWS FOR ALL TAF SITES AS WINDS ALOFT BEGIN TO INCREASE
AHEAD OF THE APPROACHING FRONTAL SYSTEM WHILE SFC WINDS REMAIN
RELATIVELY LIGHT OUT OF THE SE.
WESTERN HIGH TERRAIN TERMINALS WILL HOLD ONTO REDUCED CONDITIONS
THROUGH MUCH OF CHRISTMAS DAY AFTER WINDS SHIFT TO THE WEST
BEHIND THE COLD FRONT...WHILE CENTRAL AND EASTERN TERMINALS WILL
SEE CEILINGS IMPROVE TO THE 3000-5000` RANGE BY LATE TONIGHT OR
FAIRLY EARLY CHRISTMAS MORNING.
OUTLOOK...
FRI...FAIR AND MOSTLY VFR.
SAT...VFR.
SUN...MVFR TO IFR WITH SCATTERED RAIN SHOWERS.
MON...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL NOON EST THURSDAY FOR PAZ004>006-010>012-
017-018-024-033.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
349 PM EST WED DEC 24 2014
.SYNOPSIS...
AN INTENSIFYING STORM SYSTEM OVER WESTERN OHIO WILL MOVE UP
THROUGH THE EASTERN GREAT LAKES THIS EVENING...DRAGGING A COLD
FRONT THROUGH THE REGION OVERNIGHT. GUSTY WEST WINDS WILL DEVELOP
BEHIND THE FRONT LATE TONIGHT AND THURSDAY. ANOTHER LESS POTENT
COLD FRONT WILL MOVE ACROSS THE AREA THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
REGIONAL RADAR SHOWS A LARGE-DISORGANIZED SHIELD OF RAIN
EXTENDING ALL WAY DOWN INTO THE CAROLINAS. THE MAIN THRUST REMAINS
OFF TO THE NORTHEAST WITH THE LATEST HRRR SUGGESTING THE BEST
CHANCES FOR RAIN INTO THE EVENING BEING FROM CENTRAL PA
EASTWARD...WITH MORE IN THE WAY OF A SPOTTY LIGHT RAIN OR SHOWERS
EXPECTED OVER MY WESTERN ZONES. NOT MUCH REASON TO EXPECT OTHER
THAN A CONTINUATION OF A DREARY CHRISTMAS EVE WITH PERIODS OF RAIN
AND AREAS OF FOG.
THE COLD FRONT SHOULD BE ENTERING MY WESTERN ZONES BETWEEN ABOUT 6
AND 9 PM...AND THEN IS EXPECTED TO SPEED ACROSS THE FORECAST AREA
TO BE EXITING MY FAR EASTERN ZONES BY THE PRE DAWN HOURS OF
CHRISTMAS MORNING. THE FRONT WILL BE ACCOMPANIED BY SOME
MARGINALLY STEEP MID LEVEL LAPSE RATES WHICH COULD LEAD TO A
RUMBLE OR TWO OF THUNDER ACCOMPANYING THE SYSTEM AS IT RACES
THROUGH. EARLIER EXPECTATIONS OF SOME SORT OF NARROW COLD FRONTAL
RAIN BAND-SQUALL LINE FEATURE IS BEING DOWNPLAYED IN THE LATEST
HIGH RES MODEL GUIDANCE WHICH SHOWS A GENERAL AREA OF SHOWERS
MOVING ACROSS THE REGION THIS EVENING ALONG AND AHEAD OF THE
FRONT. THIS SHOULD DIMINISH THE THREAT OF STRONG WINDS ALOFT
BEING TRANSFERRED DOWN IN THE CONVECTION.
TEMPS WILL STAY STEADY OR EVEN CLIMB AS THE FRONT ENTERS THE
REGION THIS EVENING HELPING MIX UP THE COOL AIR DAMMED BOUNDARY
LAYER.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
CHRISTMAS DAY WILL BRING A TRANSITION INTO A PRETTY TYPICAL POST
FRONTAL COOL SEASON PATTERN...WITH CLOUDS AND BLUSTERY GUSTY
WESTERLY WINDS. HIGHER ELEVATIONS WILL LIKELY SEE WINDS AS HIGH AS
35-45 MPH...WITH THE REST OF US MAINLY EXPERIENCING WINDS IN THE
20-30 MPH RANGE.
THE USUAL SCATTERED MAINLY HIGHER ELEVATION SNOW SHOWERS WILL BE
THE FEATURED CONDITIONS...WITH THE CENTRAL RIDGE-VALLEY REGION
SEEING LITTLE MORE THAN A PASSING LIGHT RAIN OR SNOW SHOWER. THE
POST FRONTAL AIR IS NOT REALLY VERY COLD SO EVEN WHERE THE MAIN
PRECIPITATION TYPE IS EXPECTED TO BE SNOW...TEMPERATURES ABOVE
FREEZING WILL KEEP ANY ACCUMULATIONS ON THE INSIGNIFICANT SIDE.
TEMPS WILL BE STEADY OR SLOWLY FALLING FOR MUCH OF THE DAY
THURSDAY...AFTER THE INITIAL DROP OF 10F OR SO IMMEDIATELY
FOLLOWING THE CFROPA VERY EARLY ON.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
POTENT LONGWAVE UPPER TROF EXITING THE EAST COAST AT THE START OF
THE PERIOD WILL BE REPLACED BY UPPER RIDGING INTO THE WEEKEND. AS
LONGWAVE UPPER TROFFING IS FORECAST TO DEVELOP OVER THE WRN US
STARTING EARLY IN THE PD AND NRN STREAM ENERGY RETREATS INTO
EASTERN CANADA...MDT TO STRONG SWRLY FLOW ALOFT IS THEN FORECAST
TO DOMINATE THE EASTERN CONUS FROM LATE IN THE WEEKEND THROUGH THE
REMAINDER OF THE YEAR.
MEDIUM RANGE GUIDANCE IS FAIRLY CONSISTENT ESPECIALLY EARLY IN
THE PERIOD...BUT THEN SOME DIFFERENCES ARISE IN 500MB FLOW
PATTERN AFTER MONDAY AS THE ECMWF MOVES ENERGY EAST FASTER...WHILE
THE GFS CLOSES OFF AN UPPER LOW OVER THE DESERT SW.
A NORTHERN STREAM WAVE IS FORECAST TO SUPPORT A COLD FRONT MOVING
EAST ACROSS THE STATE LATE IN THE WEEKEND...POSSIBLY STALLING
NEAR THE MASON DIXON LINE INTO MONDAY AS IT ENCOUNTERS RESISTANCE
FROM THE BUILDING UPPER FLOW. THIS FRONT LOOKS TO BE THE MAIN
FOCUS FOR PCPN IN THE LONG TERM PERIOD. WITH SNOW TO THE NORTH AND
WEST...AND A MIX TO RAIN ACROSS THE SOUTH.
WITH RIDGING OR SWRLY FLOW ALOFT MUCH OF THE PERIOD WILL FEATURE
ABOVE NORMAL TEMPS...WITH A COOL DOWN TOWARD NORMAL BY NEW YEARS
EVE.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
WIDESPREAD MVFR/IFR WITH RAIN AND AREAS OF FOG WILL CONTINUE
INTO THE EVENING AS A STORM SYSTEM MOVES INTO THE EASTERN GREAT
LAKES THIS EVENING.
THE ASSOCIATED TRAILING COLD FRONT WILL PUSH THROUGH CENTRAL
PENNSYLVANIA TONIGHT. ISOLATED EMBEDDED THUNDERSTORMS CANNOT BE
RULED OUT ALONG THE FRONT. STRONG AND GUSTY WEST WINDS WILL
DEVELOP BEHIND THE FRONT TONIGHT AND THURSDAY.
INCLUDED LLWS FOR ALL TAF SITES AS WINDS ALOFT BEGIN TO INCREASE
AHEAD OF THE APPROACHING FRONTAL SYSTEM WHILE SFC WINDS REMAIN
RELATIVELY LIGHT OUT OF THE SE.
WESTERN HIGH TERRAIN TERMINALS WILL HOLD ONTO REDUCED CONDITIONS
THROUGH MUCH OF CHRISTMAS DAY AFTER WINDS SHIFT TO THE WEST
BEHIND THE COLD FRONT...WHILE CENTRAL AND EASTERN TERMINALS WILL
SEE CEILINGS IMPROVE TO THE 3000-5000` RANGE BY LATE TONIGHT OR
FAIRLY EARLY CHRISTMAS MORNING.
OUTLOOK...
FRI...FAIR AND MOSTLY VFR.
SAT...VFR.
SUN...MVFR TO IFR WITH SCATTERED RAIN SHOWERS.
MON...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 8 PM THIS EVENING TO NOON EST THURSDAY FOR
PAZ004>006-010>012-017-018-024-033.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
151 PM EST WED DEC 24 2014
.SYNOPSIS...
AN INTENSIFYING STORM SYSTEM OVER WESTERN OHIO AROUND MID DAY WILL
MOVE UP THROUGH THE EASTERN GREAT LAKES THIS EVENING...DRAGGING A
COLD FRONT THROUGH THE REGION OVERNIGHT. GUSTY WEST WINDS WILL
DEVELOP BEHIND THE FRONT LATE TONIGHT AND THURSDAY. ANOTHER LESS
POTENT COLD FRONT WILL MOVE ACROSS THE AREA THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
REGIONAL RADAR SHOWS A LARGE-DISORGANIZED SHIELD OF RAIN
EXTENDING ALL WAY DOWN INTO THE CAROLINAS. THE MAIN THRUST REMAINS
OFF TO THE NORTHEAST WITH THE LATEST HRRR SUGGESTING THE BEST
CHANCES FOR RAIN INTO THE EVENING BEING FROM CENTRAL PA
EASTWARD...WITH MORE IN THE WAY OF A SPOTTY LIGHT RAIN OR SHOWERS
EXPECTED OVER MY WESTERN ZONES. NOT MUCH REASON TO EXPECT OTHER
THAN A CONTINUATION OF A DREARY CHRISTMAS EVE WITH PERIODS OF RAIN
AND AREAS OF FOG.
THE COLD FRONT SHOULD BE ENTERING MY WESTERN ZONES BETWEEN ABOUT 6
AND 9 PM...AND THEN IS EXPECTED TO SPEED ACROSS THE FORECAST AREA
TO BE EXITING MY FAR EASTERN ZONES BY THE PRE DAWN HOURS OF
CHRISTMAS MORNING. THE FRONT WILL BE ACCOMPANIED BY SOME
MARGINALLY STEEP MID LEVEL LAPSE RATES WHICH COULD LEAD TO A
RUMBLE OR TWO OF THUNDER ACCOMPANYING THE SYSTEM AS IT RACES
THROUGH. EARLIER EXPECTATIONS OF SOME SORT OF NARROW COLD FRONTAL
RAIN BAND-SQUALL LINE FEATURE IS BEING DOWNPLAYED IN THE LATEST
HIGH RES MODEL GUIDANCE WHICH SHOWS A GENERAL AREA OF SHOWERS
MOVING ACROSS THE REGION THIS EVENING ALONG AND AHEAD OF THE
FRONT. THIS SHOULD DIMINISH THE THREAT OF STRONG WINDS ALOFT
BEING TRANSFERRED DOWN IN THE CONVECTION.
TEMPS WILL STAY STEADY OR EVEN CLIMB AS THE FRONT ENTERS THE
REGION THIS EVENING HELPING MIX UP THE COOL AIR DAMMED BOUNDARY
LAYER.
&&
.SHORT TERM /THURSDAY/...
CHRISTMAS DAY WILL BRING A TRANSITION INTO A PRETTY TYPICAL POST
FRONTAL COOL SEASON PATTERN...WITH CLOUDS AND BLUSTERY GUSTY
WESTERLY WINDS. HIGHER ELEVATIONS WILL LIKELY SEE WINDS AS HIGH AS
35-45 MPH...WITH THE REST OF US MAINLY EXPERIENCING WINDS IN THE
20-30 MPH RANGE.
THE USUAL SCATTERED MAINLY HIGHER ELEVATION SNOW SHOWERS WILL BE
THE FEATURED CONDITIONS...WITH THE CENTRAL RIDGE-VALLEY REGION
SEEING LITTLE MORE THAN A PASSING LIGHT RAIN OR SNOW SHOWER. THE
POST FRONTAL AIR IS NOT REALLY VERY COLD SO EVEN WHERE THE MAIN
PRECIPITATION TYPE IS EXPECTED TO BE SNOW...TEMPERATURES ABOVE
FREEZING WILL KEEP ANY ACCUMULATIONS ON THE INSIGNIFICANT SIDE.
TEMPS WILL BE STEADY OR SLOWLY FALLING FOR MUCH OF THE DAY
THURSDAY...AFTER THE INITIAL DROP OF 10F OR SO IMMEDIATELY
FOLLOWING THE CFROPA VERY EARLY ON.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
MORE TRANQUIL WEATHER DEVELOPING FOR THURSDAY NIGHT AND FRIDAY...
WITH SW FLOW.
DID UP TEMPS FRIDAY INTO SAT...GIVEN RISING HEIGHTS.
CUT BACK PCPN FOR LATE FRIDAY.
12Z EC RUN HAS SYSTEM FURTHER NW NOW...BUT FOR NOW WENT WITH
SLIGHT CHC OF SNOW FROM SUNDAY INTO EARLY MONDAY MORNING.
AGAIN WITH SPLIT FLOW...THERE COULD BE SOME CHANCE FOR A SOUTHERN
WAVE TO BRING SOME RAIN OR SNOW SHOWERS TO THE AREA AT TIMES...BUT
IT LOOKS LIKE ANYTHING WOULD BE FAST MOVING. PERHAPS A CHANGE
LATER NEXT WEEK...AS CROSS POLAR FLOW SETS UP.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
WIDESPREAD MVFR/IFR WITH RAIN AND AREAS OF FOG WILL CONTINUE
INTO THE EVENING AS A STORM SYSTEM MOVES INTO THE EASTERN GREAT
LAKES THIS EVENING.
THE ASSOCIATED TRAILING COLD FRONT WILL PUSH THROUGH CENTRAL
PENNSYLVANIA TONIGHT. ISOLATED EMBEDDED THUNDERSTORMS CANNOT BE
RULED OUT ALONG THE FRONT. STRONG AND GUSTY WEST WINDS WILL
DEVELOP BEHIND THE FRONT TONIGHT AND THURSDAY.
INCLUDED LLWS FOR ALL TAF SITES AS WINDS ALOFT BEGIN TO INCREASE
AHEAD OF THE APPROACHING FRONTAL SYSTEM WHILE SFC WINDS REMAIN
RELATIVELY LIGHT OUT OF THE SE.
WESTERN HIGH TERRAIN TERMINALS WILL HOLD ONTO REDUCED CONDITIONS
THROUGH MUCH OF CHRISTMAS DAY AFTER WINDS SHIFT TO THE WEST
BEHIND THE COLD FRONT...WHILE CENTRAL AND EASTERN TERMINALS WILL
SEE CEILINGS IMPROVE TO THE 3000-5000` RANGE BY LATE TONIGHT OR
FAIRLY EARLY CHRISTMAS MORNING.
OUTLOOK...
FRI...FAIR AND MOSTLY VFR.
SAT...VFR.
SUN...MVFR TO IFR WITH SCATTERED RAIN SHOWERS.
MON...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 8 PM THIS EVENING TO NOON EST THURSDAY FOR
PAZ004>006-010>012-017-018-024-033.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/MARTIN
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1150 AM CST WED DEC 24 2014
.UPDATE...
&&
.DISCUSSION...
&&
.PREV DISCUSSION... /ISSUED 1001 AM CST WED DEC 24 2014/
UPDATE...
CURRENT RADAR SHOWS RAIN/SHOWERS MOVING INTO NE PORTION OF OUR CWA.
WILL LOWER POPS OVER THE W/NW COUNTIES...BUT LATEST HRRR SUGGESTS
ONE MORE ROUND OF SCATTERED LIGHT SHOWERS THIS AFTERNOON SO WILL NOT
DROP POPS COMPLETELY. VISIBLE SATELLITE SHOWS A THIN ZONE OF
CLEARING APPROACHING WESTERN COUNTIES. CLEARING MAY BE SHORT-LIVED
AS ADDITIONAL CLOUD IS COVER WORKING ITS WAY EAST THROUGH ARKANSAS.
WILL MAKE MINOR ADJUSTMENTS TO SKY FOR THIS AFTERNOON. WILL HOLD OFF
ON ANY CHANGES TO LATER PERIODS UNTIL ALL 12Z GUIDANCE ARRIVES.
UPDATED FORECASTS/GRIDS OUT SHORTLY.
GW
PREV DISCUSSION... /ISSUED 318 AM CST WED DEC 24 2014/
DISCUSSION...
CURRENTLY A COLD FRONT WAS JUST EAST OF THE CWA WITH LIGHT
NORTHWEST WINDS AND TEMPERATURES GENERALLY IN THE MID AND UPPER
40S OVER THE AREA. RAIN...WITH A LIFTING SECOND WAVE IN THE
ARKLATEX...WAS BREAKING OUT OVER CENTRAL AND EASTERN
ARKANSAS. OTHERWISE POINTS EAST WERE CLOUDY WITH PATCHY FOG.
FOR TODAY AND TONIGHT...UPPER LEVEL TROUGH OVER THE OZARKS WILL
CONTINUE TO LIFT NORTHEAST THROUGH THE DAY AND SHEAR SOME AS IT
DOES. RAIN CHANCES WILL CONTINUE THIS MORNING THEN SLOWLY END FROM
SOUTHWEST TO NORTHEAST IN THE AFTERNOON. SKIES WILL BECOME PARTLY
CLOUDY LATE TONIGHT FROM WEST TO EAST. APPEARS THE GREATEST RISK
FOR PATCHY FOG WILL BE OVER THE EAST AFTER MIDNIGHT...WHERE
HEAVIER AMOUNTS OF RAIN FELL YESTERDAY.
CHRISTMAS DAY AND FRIDAY...NOT MUCH CHANGE NEEDED THIS PERIOD AS
MODELS SHOW THE UPPER FLOW STARTING OFF WESTERLY AND THEN QUICKLY
SHIFTING BACK SOUTHWESTERLY. LOW LEVELS WILL ALSO QUICKLY BECOME
SOUTHERLY WITH A FEW GUSTS STARTING CHRISTMAS AFTERNOON AND
PERSISTING THROUGH FRIDAY. A MIX OF CLOUDS AND SUN SHOULD BUMP
TEMPERATURES INTO THE 50S THURSDAY...AND WITH STRONGER WAA FRIDAY
MAYBE THE LOWER 60S FOR SOME. THOUGH THERE MAY BE A STRAY SHOWER
WEST OF THE MS RIVER FRIDAY AFTERNOON BETTER MOISTURE IS PROGGED
TO COME INTO THE MIDSOUTH FRIDAY NIGHT. LOWS WILL ALSO BE MILDER.
SATURDAY AND SUNDAY...THE EURO AND GFS BOTH SHOW A MOIST UPPER
LEVEL FLOW OVER A PASSING COLD FRONT. THUS TEMPERATURES WILL
BECOME COOL AGAIN...SKIES CLOUDY AND RAIN REMAINING IN THE
FORECAST. A DISTINCT SHORTWAVE MOVING IN THE FLOW ON SUNDAY MAY
SPARK A FEW HEAVIER SHOWERS SOUTH OF INTERSTATE FORTY...BUT FOR
NOW LEFT OUT ANY MENTION OF THUNDER AS BY THIS TIME LIFT ALONG THE
FRONT WILL BE WELL TO OUR SOUTHEAST.
MONDAY AND TUESDAY...PRECIPITATION CHANCES WILL DIMINISH SOME THIS
PERIOD AS DEEPER ARCTIC AIR MOVES SOUTHEAST OUT OF THE CENTRAL
PLAINS. HIGH TEMPERATURES WILL RUN APPROXIMATELY FIVE DEGREES
BELOW NORMAL MONDAY...AND CLOSER TO TEN DEGREES BY TUESDAY. A
DISTURBANCE LATE TUESDAY MAY TRIGGER A THREAT FOR LIGHT SNOW OVER
THE NORTHERN HALF OF THE AREA...BUT THERE IS PLENTY OF TIME TO SEE
IF THIS THREAT WILL MATERIALIZE INTO ANYTHING.
JAB
AVIATION...
18Z TAF CYCLE
CIGS SHOULD IMPROVE SHORTLY AT MEM AND JBR AND THEN BKN TO OVC
DECK TO SPREAD BACK OVER MEM AND JBR AND PERSIST INTO THE
EVENING. MKL AND TUP SHOULD REMAIN BKN/OVC THIS AFTERNOON. WINDS
SHOULD BE WESTERLY THIS AFTERNOON.
TONIGHT, EXPECT CLOUDS TO THIN OUT WHILE WINDS VEER MORE.
FOG TO BE AROUND LAT TONIGHT INTO EARLY TMR MORNING.
MAINLY CLEAR SKIES AND SOUTHERLY WINDS WILL BE AROUND
CHRISTMAS MORNING.
WER
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1138 AM CST WED DEC 24 2014
.UPDATE...
ISSUED AT 1005 AM CST WED DEC 24 2014
WATER VAPOR SHOWS A SHORT WAVE TROUGH MOVING NORTH NORTHEAST
THROUGH CENTRAL ILLINOIS. THIS WAVE WILL HELP TO KEEP SOME WEAK
900 TO 800 MB FRONTOGENESIS ACROSS CENTRAL AND NORTH CENTRAL
WISCONSIN AND PARTS OF SOUTHWEST WISCONSIN. SOUNDINGS SHOW THAT
THERE WILL BE SOME ICE CRYSTAL SEEDING FROM ALOFT...SO EXPECT
MAINLY SNOW. LITTLE...IF ANY...ACCUMULATION IS EXPECTED. DUE TO
THIS...INCREASE THE SNOW CHANCES UP INTO THE 20 TO 30 PERCENT
RANGE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CST WED DEC 24 2014
THE MAIN FOCUS FOR TODAY IS WITH THE CHANCES FOR SNOW/DRIZZLE.
CURRENTLY...A SHEARED OUT/POSITIVELY TILTED MID LEVEL CLOSED
TROUGH EXTENDS FROM THE UPPER MISSISSIPPI RIVER VALLEY ON DOWN TO
THE WESTERN GULF WITH THE SHEAR AXIS RIGHT OVER WEST CENTRAL
WISCONSIN/EASTERN IOWA. AT THE SURFACE...A LOW/TROUGH IS CENTERED
OVER SOUTHEAST WISCONSIN WITH NORTHWESTERLY FLOW RUNNING ACROSS
THE REGION ON THE BACK SIDE OF THIS SYSTEM. NOT MUCH IN THE WAY OF
COLD AIR BEHIND IT WITH 850MB TEMPERATURES AROUND -5C.
PRECIPITATION-WISE...DRIZZLE HAS DEVELOPED IN A BAND NORTHWEST OF
THE SURFACE LOW AND ALONG THE MID LEVEL SHEAR AXIS ALONG THE
TROUGH. 24.06Z RAP SOUNDINGS FROM ALONG THIS BAND SHOW THAT THERE
IS A LACK OF ICE ALOFT WITH SATURATED LOW LEVELS. THESE SOUNDINGS
SHOW SOME COOLING AROUND 700MB WHICH COULD PUSH THE SATURATED
LAYER DOWN INTO THE -8C RANGE AND PERHAPS CAUSE A CHANGE OVER TO
LIGHT SNOW. WITH FORCING WEAK...EXPECT THAT DRIZZLE WILL BE THE
MAIN PRECIPITATION TYPE WITH IMPACTS MINIMAL THANKS TO SURFACE
TEMPERATURES AT 32 TO 36F. THE 24.06Z HRRR/RAP TAKES THIS MAIN
BAND EASTWARD THROUGH THE MORNING AND DIMINISHING ALONG THE WAY.
AS THE TROUGH/LOW SHIFT OFF TO THE EAST TONIGHT...MID
LEVEL/SURFACE RIDGING WILL PUSH IN FROM THE WEST AND MAY OFFER A
BRIEF PERIOD WHERE SKIES CLEAR OUT LATE TONIGHT. HAVE PLAYED SKY
COVER ON THE PESSIMISTIC SIDE SINCE AS SOON AS THE LOW LEVEL
MOISTURE SHIFTS EAST...SOME HIGH LEVEL CLOUD COVER APPEARS TO MOVE
IN ACCORDING TO THE 24.00Z NAM/GFS. TEMPERATURES WILL NOT DIVE
MUCH TONIGHT WITH LOWS ONLY IN THE MID 20S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 326 AM CST WED DEC 24 2014
THE FOCUS THEN SHIFTS TO PRECIPITATION CHANCES WITH THE NEXT
SYSTEM TO MOVE IN ON THURSDAY INTO FRIDAY NIGHT. RETURN SOUTHERLY
LOW LEVEL FLOW WILL BRING WARMER AIR UP FROM THE SOUTHERN PLAINS.
THERE HAS BEEN A FAIRLY CONSISTENT MESSAGE FROM THE 24.00Z AND
PREVIOUS MODELS RUNS THAT SHOW A 900-800MB FRONTOGENETIC BAND
DEVELOPING THURSDAY AFTERNOON ACROSS CENTRAL MINNESOTA INTO
NORTHERN WISCONSIN. LOCALLY...24.00Z NAM/GFS ARE SHOWING SOME LOW
LEVEL SATURATION WITH THE WARM AIR ADVECTION TAKING PLACE THURSDAY
NIGHT. IF FORCING WAS A BIT STRONGER IN THE LOW LEVELS...THERE
WOULD BE THE POTENTIAL TO GET SOME DRIZZLE TO FORM BUT AT THE
MOMENT IT LOOKS TOO WEAK.
BROAD MID LEVEL TROUGHING WILL MOVE INTO THE REGION FRIDAY/FRIDAY
NIGHT AND BRING THE NEXT BEST CHANCE FOR SOME SNOW AS IT COMES
THROUGH. AS THE DEEPER LIFT COMES IN WITH A MID LEVEL SHORT WAVE
TROUGH TRACKING THROUGH IOWA...SNOW SHOULD DEVELOP IN A SOUTHWEST
TO NORTHEAST BAND. WITH QPF AMOUNTS AROUND A TENTH OF AN INCH OR
LESS...EXPECT THAT ANY ACCUMULATIONS WILL BE MINOR AT AN INCH OR
LESS.
THE PASSING OF THIS TROUGH WILL MARK A PERIOD OF COLDER AIR
ADVANCING INTO THE REGION FROM CANADA. A VERY CONSISTENT SIGNAL IN
THE 24.00Z GFS/ECMWF IS WITH ANOTHER WAVE OF COLDER AIR MOVING
DOWN FROM NORTHERN CANADA FOR THE MIDDLE PART OF NEXT WEEK WITH
850MB TEMPERATURES FORECAST TO DROP TO -20C OR LOWER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1138 AM CST WED DEC 24 2014
AT TAF TIME...A SNOW SHOWER WAS REDUCING VISIBILITIES TO 1 3/4
MILES AT KRST. LOOKING AT THE RADAR...THIS SNOW SHOWER WILL MOVE
QUICKLY SOUTH OF TAF SITE AND NOT EXPECTING ANY ADDITIONAL ONES
SO DID NOT INCLUDE IT IN THE FORECAST. SOUNDINGS CONTINUE TO
SUGGEST THAT KRST CEILINGS WILL REMAIN IFR THROUGH 25.09Z AND
THEN BECOME MVFR. MEANWHILE KLSE WILL CONTINUE TO SEE MVFR
CEILINGS.
AS FAR AS CLOUD COVER ON CHRISTMAS MORNING...THE LAMP GUIDANCE
SUGGESTS THAT CEILINGS WILL BECOME VFR AFTER 25.11Z AT KRST AND
25.13Z AT KLSE. HOWEVER SOUNDINGS CONTINUE TO SHOW LOW LEVEL
MOISTURE TRAPPED BELOW THE SUBSIDENCE INVERSION. FOR NOW...JUST
STAYED PESSIMISTIC.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BOYNE
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...BOYNE