Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/23/14
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
943 PM EST MON DEC 22 2014
.SYNOPSIS...
A FRONTAL BOUNDARY WILL STALL NEAR THE SOUTHEAST COAST THROUGH
TUESDAY. THIS STALLED BOUNDARY WILL EVENTUALLY LIFT NORTHWARD INTO
THE AREA AS A WARM FRONT BY WEDNESDAY. MEANWHILE, LOW PRESSURE
DEVELOPING NEAR THE NORTHERN GULF COAST LATE TUESDAY IS EXPECTED TO
STRENGTHEN AS IT TRACKS NORTHWARD INTO THE MIDWEST WEDNESDAY AND
GREAT LAKES WEDNESDAY NIGHT. A COLD FRONT WILL MOVE THROUGH EARLY
THURSDAY. HIGH PRESSURE BUILDS OVER THE EASTERN UNITED STATES FOR
THURSDAY AND FRIDAY. ANOTHER COLD FRONT IS FORECAST TO ARRIVE LATE
SATURDAY INTO SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
LATEST RAP GUIDANCE SHOWS A COUPLE LOW-LEVEL FEATURES PUSHING
ACROSS THE REGION FROM THE SOUTHWEST, NOTED BY THE DISTINCT RAIN
BANDS. WE MAINTAIN THE CURRENT POP FORECAST, CATEGORICAL ACROSS
THE NORTH WITH SLIGHTLY LESS ACROSS EXTREME SOUTHERN DELMARVA.
HAVE ALSO DROPPED THE FREEZING RAIN ADVISORY WITH THIS UPDATE AS
TEMPERATURES ARE ABOVE FREEZING IN MOST LOCATIONS. THERE COULD BE
SOME LINGERING AT OR BELOW FREEZING TEMPERATURES IN THE HIGHEST
ELEVATIONS IN CARBON/MONROE, BUT THIS CAN BE HANDLED BY AN SPS.
OTHERWISE, AS THE AIRMASS MOISTENS AND THE LOW-LEVEL INVERSION
STRENGTHENS, SOME DRIZZLE MAY OCCUR ALONG WITH SOME FOG. GIVEN THE WAA
FORECAST, DESPITE THE LIGHT FLOW, THE TEMPERATURES WERE SHOWN TO
MAINLY BE STEADY OR EVEN SLOWLY RISE DURING THE NIGHT. LOW
TEMPERATURES WERE MOSTLY A BLEND OF THE NAM/GFS MOS. THE LAMP/LAV
GUIDANCE WAS USED TO ASSIST WITH THE HOURLY TEMPERATURES AND DEW
POINTS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
THE SYNOPTIC SETUP IS COMPRISED OF AN UPPER-LEVEL TROUGH TO OUR
WEST. THIS WILL DRIVE LOW PRESSURE TOWARD THE GREAT LAKES WITH
CONTINUED LOW-LEVEL WAA ACROSS OUR AREA. A WEAK SURFACE LOW SLIDING
NORTHWARD OFF OF THE MID ATLANTIC COAST SHOULD TEND TO WEAKEN
FURTHER DURING THE COURSE OF THE DAY AS SOME RIDGING BUILDS. THE
COMBINATION OF THIS WEAKENING FEATURE, A LOW-LEVEL INVERSION AND
PLENTY OF MOISTURE BENEATH IT SPELLS UNSETTLED WEATHER.
THE FORECAST SOUNDINGS OVERALL SHOW AS THE LARGE SCALE LIFT WANES,
SOME DRYING OCCURS ALOFT. THIS WOULD TEND TO LEAD TO SOME DRIZZLE
AND FOG ACROSS MUCH OF THE AREA, ASSUMING THE LOW CLOUDS DO INDEED
LOCK IN. THE MORE FOCUSED RAIN MAY BE ACROSS OUR NORTHERN ZONES
BEFORE LIFTING NORTH OF OUR CWA, THEN LEFTOVER DRIZZLE AROUND. WE
TRENDED THE POPS TO REFLECT THIS IDEA AS MUCH OF THE QPF SHOULD BE
ON THE LIGHT SIDE.
AS FOR THE HIGH TEMPERATURES, WE USED AN EVEN GFS/NAM MOS BLEND BUT
THEN ADJUSTED THESE DOWN SOME DUE TO THE EXPECTED LOW CLOUDS AND
LIGHT RAIN/DRIZZLE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
THE LARGE SCALE PATTERN DURING MIDWEEK WILL FEATURE A HIGH AMPLITUDE
TROUGH OVER THE CENTRAL CONUS AND DOWNSTREAM RIDGE OVER THE WESTERN
ATLANTIC. CYCLOGENESIS IS FORECAST TO OCCUR ALONG THE NORTHERN GULF
COAST LATE TUESDAY. THE SURFACE LOW IS THEN FORECAST TO TRACK
NORTHWARD THROUGH THE DEEP SOUTH TUESDAY NIGHT AND MIDWEST ON
WEDNESDAY. THIS TRACK MEANS THE WARM SECTOR WILL BECOME ESTABLISHED
UP THE EASTERN SEABOARD OWING TO A DEEP SOUTHERLY FETCH ON THE EAST
SIDE OF THE STORM SYSTEM. FORECAST SOUNDINGS ARE ONLY SUPPORTIVE ON
ONE PTYPE WITH THIS EVENT: RAIN. THERE IS AN OPPORTUNITY FOR A
BRIEF LULL IN THE RAIN TUESDAY EVENING WHEN THE INITIAL BAND OF
ISENTROPIC LIFT PASSES TO OUR NORTH. A LARGE PRECIP SHIELD OVER THE
SOUTHEAST STATES IS EXPECTED TO EXPAND NORTHWARD INTO THE NORTHERN
MID ATLANTIC LATE TUESDAY NIGHT AND WEDNESDAY MORNING. RAIN SHOULD
BECOME WIDESPREAD AND MODERATE AT TIMES ON CHRISTMAS EVE BOTH DURING
THE DAY AND AT NIGHT. ADDED A SLIGHT CHANCE OF THUNDERSTORMS NEAR
THE DE AND SOUTHERN NJ COAST AS WELL. NOT EXPECTING A LOT OF HYDRO
ISSUES WITH QPF BETWEEN 0.75 AND 1.50 INCHES FOR THIS EVENT.
MODELS HAVE TRENDED SLIGHTLY SLOWER WITH THE COLD FRONT, INDICATING
A LATE WEDNESDAY NIGHT/EARLY THURSDAY MORNING FROPA WITH TODAY`S 12Z
GUIDANCE COMPARED TO A WEDNESDAY EVENING PASSAGE FROM YESTERDAY`S
RUNS. WE FAVORED A MORE PROGRESSIVE SOLUTION WHERE THE PRECIP ENDS
BY CHRISTMAS MORNING SINCE THE UPPER TROUGH IS EXPECTED TO
DE-AMPLIFY, ALLOWING FOR MORE OF AN EASTWARD PUSH WITH THE FRONTAL
BOUNDARY.
WESTERLY WINDS BEHIND THE FRONT WILL ADVECT COLDER AND DRIER AIR
INTO THE REGION ON THURSDAY. SKIES MAY CLEAR IN THE MORNING BEFORE
POST-FRONTAL STRATOCU IS EXPECTED TO DEVELOP BY THE AFTERNOON. IT
WILL BE BREEZY DURING THE DAY AS BUFKIT MOMENTUM TRANSFER FROM THE
12Z GFS SHOWS THE POTENTIAL FOR 30 TO 40 MPH GUSTS. MAX TEMPS IN THE
UPPER 40S AND LOWER 50S MAY OCCUR IN THE EARLY MORNING JUST PRIOR TO
FROPA BEFORE DROPPING THRUOUT THE DAY. A FEW FLURRIES MAY REACH THE
POCONOS DURING THE AFTERNOON.
BROAD AREA OF HIGH PRESSURE BUILDS ALONG THE EASTERN SEABOARD
THURSDAY NIGHT AND FRIDAY. QUIET CONDITIONS AND SLIGHTLY ABOVE
NORMAL TEMPS ARE IN STORE TO END THE WEEK.
THERE IS STILL A LARGE FORECAST SPREAD WITH THE LATEST 12Z MODELS
FOR THIS WEEKEND. THE ECMWF REMAINS THE MOST BULLISH WITH LOW
PRESSURE DEVELOPING OVER THE GULF COAST STATES THIS WEEKEND AS A
RESULT OF A STRONG SHORTWAVE TROUGH TRACKING ACROSS THE SOUTHERN
STATES. THIS MODEL THEN SIMULATES THE LOW STRENGTHENING AS IT MOVES
NORTHEASTWARD TOWARD THE MID-ATLANTIC STATES AND STARTS TO PHASE
WITH NORTHERN STREAM ENERGY SUNDAY AND SUNDAY NIGHT. MEANWHILE, THE
GFS SHOWS A MUCH MORE PROGRESSIVE PATTERN WITH THE ABOVE MENTIONED
SHORTWAVE TROUGH PUSHING A WEAK COLD FRONT THRU THE MID ATLANTIC
EARLIER IN THE WEEKEND. SIDED CLOSELY WITH WPC FOR THE WEEKEND
FORECAST, WHICH WAS WEIGHTED MORE TOWARD THE NAEFS/ECMWF ENSEMBLE
MEAN. LOW CHANCE POPS FOR RAIN NEAR THE COAST AND RAIN/SNOW INLAND
WERE INCLUDED FOR LATE IN THE WEEKEND.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...MVFR CEILINGS ARE ANTICIPATED TO LOWER TO IFR/LIFR WITH
LIGHT RAIN AND DRIZZLE. SOME FOG WILL OCCUR AS THE CEILINGS LOWER,
WHICH WILL BRING THE VISIBILITIES DOWN. NORTHEAST WINDS GENERALLY
AROUND 5 KNOTS.
TUESDAY...THE CEILINGS SHOULD REMAIN AROUND IFR AS THE LOW-LEVEL
MOISTURE BECOMES TRAPPED. THIS WILL ALSO COMBINE WITH SOME LIGHT
RAIN OR DRIZZLE. NORTHEAST WINDS 5 KNOTS OR LESS, POSSIBLY TURNING
LOCALLY SOUTHEAST IN THE AFTERNOON.
OUTLOOK...
TUESDAY NIGHT...MAY BE A LULL IN PRECIP TUESDAY EVENING BEFORE
MORE RAIN MOVES BACK INTO THE AREA OVERNIGHT. STILL EXPECTING MVFR
AND IFR CONDITIONS.
WEDNESDAY AND WEDNESDAY NIGHT...MAINLY IFR CONDITIONS IN LOW CLOUDS
AND RAIN. THE RAIN WILL BE STEADY AND MODERATE AT TIMES. SOUTHERLY
WINDS ARE FORECAST TO INCREASE TO NEAR 50 KT LESS THAN 1000 FT AGL
WEDNESDAY AFTERNOON AND EVENING. MAY SEE LLWS DURING THIS TIME
ESPECIALLY IF WEDGE OF COLDER AIR NEAR THE SURFACE IS MORE STUBBORN
TO ERODE THAN MODELS INDICATE, MAKING THE THERMAL INVERSION STRONGER.
THURSDAY...MVFR LINGERING EARLY, IMPROVING TO VFR DURING THE DAY.
BREEZY WEST WINDS GUSTING 30-25 KT.
THURSDAY NIGHT THROUGH SATURDAY...VFR AND LIGHT WINDS.
&&
.MARINE...
WE ARE STARTING TO SEE AN UPTICK IN THE SEAS ACROSS OUR WATERS
WITH THE MOST NOTICEABLE INCREASE ACROSS THE SOUTH. WE EXPECT,
WITH A STRENGTHENING NORTHEASTRLY FLOW, TO SEE SEAS ACROSS THE
SOUTH CLIMB CLOSE TO 6 FEET LATER TONIGHT. WE HAVE THEREFORE
ISSUED A SCA WITH WINDS AND SEAS THROUGH TOMORROW LATE MORNING
WHEN THE PRESSURE GRADIENT SHOULD RELAX ENOUGH TO ALLOW THE
ELEVATED SEA CONDITIONS SUBSIDE A BIT. ELSEWHERE, THE TRAJECTORY
AND THE AMOUNT OF FETCH DO NOT APPEAR CONDUCIVE FOR SCA SEAS AND
GUSTS. THE WINDS SHOULD LESSEN TUESDAY AS THE SURFACE LOW WEAKENS.
OUTLOOK...
TUESDAY NIGHT...SOUTH WINDS BELOW SCA CRITERIA. WAVES FORECAST TO
BUILD TO 4 FT OFF THE DE COAST.
WEDNESDAY AND WEDNESDAY NIGHT...WIDESPREAD SCA CONDITIONS EXPECTED
WITH SEAS BUILDING TO 5-8 FT AND SOUTHERLY WINDS SUSTAINED 20-25 KT.
STABLE LAPSE RATES WILL LIMIT MIXING POTENTIAL SO NOT EXPECTING MUCH
HIGHER GUSTS, EXCEPT IF CONVECTION IS ABLE TO DEVELOP OVER THE OCEAN.
THURSDAY...WEST WIND GUSTING IN EXCESS OF 25 KNOTS EXPECTED. GALES
ARE EVEN POSSIBLE DURING FOR A PERIOD. 5 TO 8 FEET SEAS FORECAST FOR
THE OCEAN.
THURSDAY NIGHT THROUGH SATURDAY...NO MARINE HEADLINES EXPECTED AT
THIS TIME.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST TUESDAY FOR ANZ453>455.
&&
$$
SYNOPSIS...KLEIN
NEAR TERM...GORSE/HEAVENER
SHORT TERM...GORSE
LONG TERM...KLEIN
AVIATION...GORSE/HEAVENER/KLEIN
MARINE...GORSE/IOVINO/HEAVENER/KLEIN
AREA FORECAST DISCUSSION
NWS MIAMI FL
755 PM EST MON DEC 22 2014
.UPDATE...NO CHANGES TO THE FORECAST THIS EVENING. PWAT ON THE
EVENING MIAMI SOUNDING IS ONLY 1.34 INCHES AND WITH A LACK OF
FORCING, A TRANQUIL NIGHT IS EXPECTED TO CONTINUE. A RATHER MUGGY
LIGHT SOUTHEAST WIND FLOW WILL CONTINUE. READINGS WILL ONLY FALL
A FEW MORE DEGREES AS DEWPOINTS ARE NOW AROUND 70F, SO FORECAST
LOWS CONTINUE TO LOOK IN GOOD SHAPE AND NO CHANGES ARE NECESSARY
THIS EVENING. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 712 PM EST MON DEC 22 2014/
AVIATION...
MAIN CONCERN FOR THIS TAF CYCLE CONTINUES TO BE THE LOW CIG
POTENTIAL ACROSS ALL TAF SITES. SOUTHEAST FLOW SHOULD DECREASE
SLIGHTLY DURING THE OVERNIGHT PERIOD...LESS THAN 10
KNOTS...BEFORE INCREASING AGAIN DURING THE DAY TOMORROW. BELIEVE
THE BIGGEST THREAT FOR LOW CIGS SHOULD BE ACROSS THE INTERIOR AND
GULF COAST MAINLY AFFECTING KAPF. LATEST LAMP GUIDANCE ALONG WITH
THE HRRR IS EVEN SUGGESTING IFR CIGS OVERNIGHT AT KAPF. DECIDED TO
INTRODUCE A TEMPO MENTION FOR BRIEF IFR CIGS AND MVFR VSBY AT KAPF
AS GUIDANCE HAS REMAINED FAIRLY CONSISTENT OVER THE LAST 24 HOURS.
GUIDANCE WAS FAIRLY UNIFORM DEPICTING MVFR CIGS AT ALL EAST COAST
SITES THROUGH MUCH OF THE OVERNIGHT AND EARLY MORNING PERIOD...SO
PREVAILED BKN010-015 AFTER 08Z. COULD SEE BRIEF IFR CIGS AT KTMB
BUT LEFT MENTION OUT OF TAFS FOR NOW.
PREV DISCUSSION... /ISSUED 312 PM EST MON DEC 22 2014/
DISCUSSION...
DRY...WARM AND PARTLY SUNNY CONDITIONS CONTINUE ACROSS SOUTH
FLORIDA THIS AFTERNOON. THE MID/UPPER LEVEL PATTERN CONSISTED OF
A RIDGE OF HIGH PRESSURE CENTERED NEAR THE DOMINICAN REPUBLIC AND
STRETCHING NORTHWARD OVER THE WESTERN ATLANTIC NEAR THE EASTERN
SEABOARD...AND A TROUGH DIGGING INTO THE NORTHERN/CENTRAL PLAINS.
AT THE SURFACE...HIGH PRESSURE WAS OVER THE WESTERN
ATLANTIC...WITH A SOUTHEAST FLOW ACROSS SOUTH FLORIDA. THE
SOUTHEAST FLOW WAS BRINGING INCREASING DEWPOINTS ACROSS THE
REGION...AND TEMPERATURES OVERNIGHT ALONG THE EAST COAST WILL
REMAIN WELL ABOVE NORMAL IN THE LOWER 70S.
AN AMPLIFIED PATTERN WILL REMAIN IN PLACE ON TUESDAY AS THE UPPER
TROUGH DIGS INTO TEXAS AND THE UPPER RIDGE REMAINS OVER THE
CARIBBEAN AND ALONG THE EASTERN SEABOARD. AN AREA OF LOW PRESSURE
IS FORECAST TO DEVELOP ALONG THE NORTHERN GULF COAST...AND THE
PRESSURE GRADIENT WILL INCREASE IN THE AFTERNOON. DRY LOW/MID
LEVEL AIR WILL CONTINUE TO PUSH INTO THE REGION ON
TUESDAY...ROTATING AROUND HIGH PRESSURE OVER THE WESTERN ATLANTIC.
SO ANOTHER DRY...MUGGY AND WARM DAY IS IN STORE FOR SOUTH
FLORIDA...WITH TEMPERATURES IN THE LOW TO MID 80S AND DEWPOINTS
AROUND 70. OVERNIGHT LOWS WILL BE VERY WARM ONCE AGAIN...AND NEAR
RECORD HIGH MINIMUMS IN THE UPPER 60S TO MID 70S.
LOW PRESSURE IS FORECAST TO PUSH INTO THE SOUTHEAST AND THEN OHIO
VALLEY ON WEDNESDAY...WITH TRAILING COLD FRONT PUSHING INTO THE
FLORIDA PENINSULA. MODEL GUIDANCE HAS CONTINUED TO SLOW DOWN THE
TIMING OF THE FRONT...AND IT APPEARS THE FRONT WILL MOVE INTO THE
REGION LATE WEDNESDAY. THE FRONT IS THEN FORECAST TO PUSH THROUGH
THE REGION ON CHRISTMAS MORNING. HOWEVER...MOISTURE WILL LINGER
BEHIND THE FRONT...WITH CLOUD COVER AND SHOWERS REMAINING INTO THE
AFTERNOON HOURS. THE BEST DYNAMICS WILL REMAIN ACROSS CENTRAL
FLORIDA AND THEN OUT INTO THE WESTERN ATLANTIC. INSTABILITY WILL
ALSO BE MARGINAL AS THE FRONT MOVES INTO THE REGION
OVERNIGHT...AND WINDS MAY ALSO VEER TO THE SOUTHWEST AHEAD OF THE
FRONT. SPC HAS THE REGION IN A MARGINAL RISK FOR SEVERE WEATHER.
THE BEST BET FOR STRONGER STORMS APPEARS TO BE FROM NAPLES TO THE
LAKE REGION AND NORTHWARD.
RIDGING WILL HOLD ON OVER THE CARIBBEAN AND BAHAMAS...AND THE
TROUGH WILL LIFT NORTHEASTWARD AND FLATTEN OUT ON THURSDAY. THE
FRONT WILL THEN STALL OVER THE FLORIDA STRAITS THROUGH THE END OF
THE WEEK...WITH HIGH PRESSURE BUILDING INTO THE SOUTHEAST AND THEN
WESTERN ATLANTIC. SO COLD AIR ADVECTION WILL BE SHORT
LIVED...WITH TEMPERATURES ONLY BRIEFING FALLING TO NEAR NORMAL FOR
CHRISTMAS DAY AND FRIDAY.
THE MID/UPPER LEVEL RIDGE IS FORECAST TO BUILD ACROSS THE REGION
OVER THE WEEKEND. MOISTURE WILL QUICKLY RETURN...WITH DEWPOINTS
INCREASING BACK INTO THE MID TO UPPER 60S. TEMPERATURES ARE
FORECAST TO INCREASE TO THE UPPER 70S TO LOWER 80S. A SHORTWAVE
WILL PUSH ACROSS THE FOUR CORNERS REGION ON SATURDAY AND THEN LIFT
NORTHEAST AROUND THE RIDGE OF HIGH PRESSURE INTO THE OHIO VALLEY
ON SUNDAY. A SURFACE LOW IS THEN FORECAST TO PUSH INTO THE
NORTHEAST OR GREAT LAKES...WITH A WEAK FRONT PUSHING INTO
NORTHERN AND CENTRAL FLORIDA BEFORE STALLING.
MARINE...
SOUTHEAST FLOW CONTINUES THROUGH TUESDAY, WITH WINDS VEERING TO
THE SOUTH ON WEDNESDAY. A COLD FRONT WILL APPROACH THE GULF
WATERS WEDNESDAY AFTERNOON, THEN INTO THE ATLANTIC WATERS LATE
WEDNESDAY INTO EARLY CHRISTMAS DAY. NORTHWEST AND NORTH WINDS ARE
EXPECTED BY THURSDAY. SEAS WILL BUILD, ESPECIALLY THROUGH THE
OFFSHORE GULF WATERS WEDNESDAY NIGHT INTO EARLY CHRISTMAS DAY.
HIGH PRESSURE AND NORTHEASTERLY FLOW RETURN TO END THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 83 74 84 / 10 10 10 20
FORT LAUDERDALE 73 83 75 83 / 10 10 10 20
MIAMI 72 83 73 84 / 10 10 10 20
NAPLES 67 83 69 82 / 0 10 10 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
712 PM EST MON DEC 22 2014
.AVIATION...
MAIN CONCERN FOR THIS TAF CYCLE CONTINUES TO BE THE LOW CIG
POTENTIAL ACROSS ALL TAF SITES. SOUTHEAST FLOW SHOULD DECREASE
SLIGHTLY DURING THE OVERNIGHT PERIOD...LESS THAN 10
KNOTS...BEFORE INCREASING AGAIN DURING THE DAY TOMORROW. BELIEVE
THE BIGGEST THREAT FOR LOW CIGS SHOULD BE ACROSS THE INTERIOR AND
GULF COAST MAINLY AFFECTING KAPF. LATEST LAMP GUIDANCE ALONG WITH
THE HRRR IS EVEN SUGGESTING IFR CIGS OVERNIGHT AT KAPF. DECIDED TO
INTRODUCE A TEMPO MENTION FOR BRIEF IFR CIGS AND MVFR VSBY AT KAPF
AS GUIDANCE HAS REMAINED FAIRLY CONSISTENT OVER THE LAST 24 HOURS.
GUIDANCE WAS FAIRLY UNIFORM DEPICTING MVFR CIGS AT ALL EAST COAST
SITES THROUGH MUCH OF THE OVERNIGHT AND EARLY MORNING PERIOD...SO
PREVAILED BKN010-015 AFTER 08Z. COULD SEE BRIEF IFR CIGS AT KTMB
BUT LEFT MENTION OUT OF TAFS FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 312 PM EST MON DEC 22 2014/
DISCUSSION...
DRY...WARM AND PARTLY SUNNY CONDITIONS CONTINUE ACROSS SOUTH
FLORIDA THIS AFTERNOON. THE MID/UPPER LEVEL PATTERN CONSISTED OF
A RIDGE OF HIGH PRESSURE CENTERED NEAR THE DOMINICAN REPUBLIC AND
STRETCHING NORTHWARD OVER THE WESTERN ATLANTIC NEAR THE EASTERN
SEABOARD...AND A TROUGH DIGGING INTO THE NORTHERN/CENTRAL PLAINS.
AT THE SURFACE...HIGH PRESSURE WAS OVER THE WESTERN
ATLANTIC...WITH A SOUTHEAST FLOW ACROSS SOUTH FLORIDA. THE
SOUTHEAST FLOW WAS BRINGING INCREASING DEWPOINTS ACROSS THE
REGION...AND TEMPERATURES OVERNIGHT ALONG THE EAST COAST WILL
REMAIN WELL ABOVE NORMAL IN THE LOWER 70S.
AN AMPLIFIED PATTERN WILL REMAIN IN PLACE ON TUESDAY AS THE UPPER
TROUGH DIGS INTO TEXAS AND THE UPPER RIDGE REMAINS OVER THE
CARIBBEAN AND ALONG THE EASTERN SEABOARD. AN AREA OF LOW PRESSURE
IS FORECAST TO DEVELOP ALONG THE NORTHERN GULF COAST...AND THE
PRESSURE GRADIENT WILL INCREASE IN THE AFTERNOON. DRY LOW/MID
LEVEL AIR WILL CONTINUE TO PUSH INTO THE REGION ON
TUESDAY...ROTATING AROUND HIGH PRESSURE OVER THE WESTERN ATLANTIC.
SO ANOTHER DRY...MUGGY AND WARM DAY IS IN STORE FOR SOUTH
FLORIDA...WITH TEMPERATURES IN THE LOW TO MID 80S AND DEWPOINTS
AROUND 70. OVERNIGHT LOWS WILL BE VERY WARM ONCE AGAIN...AND NEAR
RECORD HIGH MINIMUMS IN THE UPPER 60S TO MID 70S.
LOW PRESSURE IS FORECAST TO PUSH INTO THE SOUTHEAST AND THEN OHIO
VALLEY ON WEDNESDAY...WITH TRAILING COLD FRONT PUSHING INTO THE
FLORIDA PENINSULA. MODEL GUIDANCE HAS CONTINUED TO SLOW DOWN THE
TIMING OF THE FRONT...AND IT APPEARS THE FRONT WILL MOVE INTO THE
REGION LATE WEDNESDAY. THE FRONT IS THEN FORECAST TO PUSH THROUGH
THE REGION ON CHRISTMAS MORNING. HOWEVER...MOISTURE WILL LINGER
BEHIND THE FRONT...WITH CLOUD COVER AND SHOWERS REMAINING INTO THE
AFTERNOON HOURS. THE BEST DYNAMICS WILL REMAIN ACROSS CENTRAL
FLORIDA AND THEN OUT INTO THE WESTERN ATLANTIC. INSTABILITY WILL
ALSO BE MARGINAL AS THE FRONT MOVES INTO THE REGION
OVERNIGHT...AND WINDS MAY ALSO VEER TO THE SOUTHWEST AHEAD OF THE
FRONT. SPC HAS THE REGION IN A MARGINAL RISK FOR SEVERE WEATHER.
THE BEST BET FOR STRONGER STORMS APPEARS TO BE FROM NAPLES TO THE
LAKE REGION AND NORTHWARD. TEMPERATURE
RIDGING WILL HOLD ON OVER THE CARIBBEAN AND BAHAMAS...AND THE
TROUGH WILL LIFT NORTHEASTWARD AND FLATTEN OUT ON THURSDAY. THE
FRONT WILL THEN STALL OVER THE FLORIDA STRAITS THROUGH THE END OF
THE WEEK...WITH HIGH PRESSURE BUILDING INTO THE SOUTHEAST AND THEN
WESTERN ATLANTIC. SO COLD AIR ADVECTION WILL BE SHORT
LIVED...WITH TEMPERATURES ONLY BRIEFING FALLING TO NEAR NORMAL FOR
CHRISTMAS DAY AND FRIDAY.
THE MID/UPPER LEVEL RIDGE IS FORECAST TO BUILD ACROSS THE REGION
OVER THE WEEKEND. MOISTURE WILL QUICKLY RETURN...WITH DEWPOINTS
INCREASING BACK INTO THE MID TO UPPER 60S. TEMPERATURES ARE
FORECAST TO INCREASE TO THE UPPER 70S TO LOWER 80S. A SHORTWAVE
WILL PUSH ACROSS THE FOUR CORNERS REGION ON SATURDAY AND THEN LIFT
NORTHEAST AROUND THE RIDGE OF HIGH PRESSURE INTO THE OHIO VALLEY
ON SUNDAY. A SURFACE LOW IS THEN FORECAST TO PUSH INTO THE
NORTHEAST OR GREAT LAKES...WITH A WEAK FRONT PUSHING INTO
NORTHERN AND CENTRAL FLORIDA BEFORE STALLING.
MARINE...
SOUTHEAST FLOW CONTINUES THROUGH TUESDAY, WITH WINDS VEERING TO
THE SOUTH ON WEDNESDAY. A COLD FRONT WILL APPROACH THE GULF
WATERS WEDNESDAY AFTERNOON, THEN INTO THE ATLANTIC WATERS LATE
WEDNESDAY INTO EARLY CHRISTMAS DAY. NORTHWEST AND NORTH WINDS ARE
EXPECTED BY THURSDAY. SEAS WILL BUILD, ESPECIALLY THROUGH THE
OFFSHORE GULF WATERS WEDNESDAY NIGHT INTO EARLY CHRISTMAS DAY.
HIGH PRESSURE AND NORTHEASTERLY FLOW RETURN TO END THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 83 74 84 / 10 10 10 20
FORT LAUDERDALE 73 83 75 83 / 10 10 10 20
MIAMI 72 83 73 84 / 10 10 10 20
NAPLES 67 83 69 82 / 0 10 10 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...84/AK
LONG TERM....84/AK
AVIATION...10/CD
EAST CENTRAL FLORIDA FORECAST DISCUSSION
NWS MELBOURNE FL
956 AM EST SUN DEC 21 2014
.DISCUSSION...
...MORE HUMID AND WARMER THROUGH WED...
...INCREASED RAIN CHANCES LATE TODAY INTO MON THEN AGAIN LATE TUE
AND WED AHEAD OF NEXT COLD FRONT...
CURRENTLY...
A FEW STORMS SINCE EARLY AM OVER THE EASTERN GULF ARE ASCD WITH
FAVORABLE JET ASCD LIFT AND PRESENCE OF UPR WAVE ENERGY MOVING
ACROSS THE SE STATES. A REVIEW OF AM SOUNDINGS FROM TBW AND XMR SHOW
SUITABLE MOISTURE AND INSTABILITY FOR DEVELOPMENT OF A FEW STORMS
LATER THIS AFTERNOON ROUGHLY ALONG AND NORTH OF THE I-4 CORRIDOR AND
BEACHLINE EXPRESSWAY. THIS MOVES UP THE PERIOD FOR MENTIONING STORMS
ABOUT SIX HOURS FROM EARLIER THINKING. RAPID STEERING AT STORM LEVEL
WL LEAD TO SOME BRIEF MODERATE TO HEAVY RAIN IN AFFECTED AREAS ALONG
WITH WIND GUSTS OF 40 TO 45 MPH AND LIGHTING. DIGITAL AND TEXT PKGS
HAVE BEEN UPDATED FOR ADDITION OF AFTERNOON THUNDER.
(FROM PREV DISC)...STATIONARY FRONT LAYING INSIDE A WEAK INVERTED
TROF EXTENDING FROM THE SW GOMEX ACRS THE NRN FL PENINSULA. EVENING
SOUNDINGS SHOW INCRSG MOISTURE ACRS THE CENTRAL PENINSULA WITH PWAT
VALUES ARND 1.4"...UP FROM 0.8" FROM THE 20/00Z FLIGHT...A FEW
POCKETS OF DRY AIR REMAIN BLO THE H70 LYR THAT INDICATE ADDITIONAL
POTENTIAL FOR MOISTURE LOADING. TO THE S...KMFL HAS MOISTENED TO
1.2" UP FROM 0.9" FROM 20/00Z BUT STILL SHOWS THE REFLECTION OF A
HIGH PRES RIDGE OVER THE FL STRAITS AND THE CENTRAL BAHAMAS WITH
SUBSTANTIAL DRY AIR ABV A SUBSIDENCE INVERSION IN THE H80-H75 LYR.
TO THE N...BOTH KJAX/KTAE ARE NEARLY SATURATED THRU THE H100-H70 LYR
WITH VERY DRY AIR ABV AN INVERSION IN THE H70-H60 LYR. RUC ANALYSIS
INDICATES PLENTIFUL UPSTREAM MOISTURE WITH H100-H70 MEAN RH VALUES
OVER THE GOMEX LARGELY AOA 80PCT...H85-H50 VALUES AOA 50PCT BUT AS
HIGH AS 90PCT WITHIN THE VCNTY OF THE STATIONARY FRONT.
&&
.AVIATION...THRU 22/06Z
THROUGH 15Z-21/18Z...S 5-8KTS WITH VFR CONDS. BTWN
21/18Z-21/22Z...INTERIOR SITES S/SW 4-7KTS WITH MVFR/ISOLD SHRA AND
TS N OF LINE FM KISM-KCOF...COASTAL SITES S/SE 6-9KTS. AFT
21/22Z...S/SE AOB 5KTS.
FM 21/18Z-22/03Z...S OF KCOF-KISM SLGT CHC MVFR SHRAS. AFT
22/03Z...N OF KTIX-KISM PREVAILING MVFR IN NMRS/WDSPRD RA WITH PDS
IFR +RA...S OF KTIX-KISM CHC MVFR SHRAS.
CIGS:
N OF KCOF-KISM: THRU 22/03Z...BTWN FL060-080 WITH PDS MVFR BTWN
FL015-025 IN SCT SHRAS. AFT 22/03Z...MVFR BTWN FL010-020.
S OF KCOF-KLAL: THRU 22/03Z...BTWN FL080-100 WITH PDS MVFR BTWN
FL020-030 IN ISOLD -SHRAS. AFT 22/03Z...BTWN FL060-080 WITH PDS MVFR
BTWN FL015-025 IN SCT -SHRAS.
&&
.MARINE...
DETERIORATING WX CONDS AS A WEAK STATIONARY FRONT JUST N OF THE I-4
CORRIDOR KEEPS THE LCL PGRAD DISRUPTED AND SERVES AS A FOCUS FOR
SHRA AND ISOLD TSRAS. SFC WNDS S-SE BTWN 4-8KTS FROM CAPE CANAVERAL
SWD...VRBL AOB 5KTS N OF THE CAPE IN THE VCNTY OF THE FRONT. SEAS
AOB 2FT...BUILDING TO 2-3FT OVER THE OFFSHORE LEG AFT MIDDAY.
N OF THE CAPE...SCT SHRAS AFT MIDDAY...BCMG NMRS/WDSPRD WITH ISOLD
TSRAS IN AFTN/EVE. S OF THE CAPE...ISOLD/SCT SHRAS AFT
MIDDAY...CONTG THRU THE OVERNIGHT PD.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
JP/DKW
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
412 AM EST SUN DEC 21 2014
.DISCUSSION...
...MORE HUMID AND WARMER THROUGH WED...
...INCREASED RAIN CHANCES LATE TODAY INTO MON THEN AGAIN LATE TUE
AND WED AHEAD OF NEXT COLD FRONT...
CURRENTLY...
STATIONARY FRONT LAYING INSIDE A WEAK INVERTED TROF EXTENDING FROM
THE SW GOMEX ACRS THE NRN FL PENINSULA. EVENING SOUNDINGS SHOW
INCRSG MOISTURE ACRS THE CENTRAL PENINSULA WITH PWAT VALUES ARND
1.4"...UP FROM 0.8" FROM THE 20/00Z FLIGHT...A FEW POCKETS OF DRY
AIR REMAIN BLO THE H70 LYR THAT INDICATE ADDITIONAL POTENTIAL FOR
MOISTURE LOADING. TO THE S...KMFL HAS MOISTENED TO 1.2" UP FROM 0.9"
FROM 20/00Z BUT STILL SHOWS THE REFLECTION OF A HIGH PRES RIDGE OVER
THE FL STRAITS AND THE CENTRAL BAHAMAS WITH SUBSTANTIAL DRY AIR ABV
A SUBSIDENCE INVERSION IN THE H80-H75 LYR. TO THE N...BOTH KJAX/KTAE
ARE NEARLY SATURATED THRU THE H100-H70 LYR WITH VERY DRY AIR ABV AN
INVERSION IN THE H70-H60 LYR. RUC ANALYSIS INDICATES PLENTIFUL
UPSTREAM MOISTURE WITH H100-H70 MEAN RH VALUES OVER THE GOMEX
LARGELY AOA 80PCT...H85-H50 VALUES AOA 50PCT BUT AS HIGH AS 90PCT
WITHIN THE VCNTY OF THE STATIONARY FRONT.
ALOFT...A 100-120KT ZONAL JET STREAK EXTENDING FROM THE RIO GRANDE
VALLEY TO BERMUDA IS PARALLEL TO THE STATIONARY FRONT AND IS
GENERATING A BROAD LINE OF UPR LVL DIVERGENCE. THOUGH THIS LINE HAS
MARGINAL STRENGTH/ORGANIZATION...VORTICITY AND OMEGA FIELDS SHOW
SIMILAR AXES...WITH ALL THREE NEARLY VERTICALLY STACKED. MODERATELY
COOL AIR REMAINS IN PLACE WITH H50 TEMPS HOLDING ARND -10C. H70-H50
LAPSE RATES STEEPEN FROM ARND 5.5C/KM OVER THE PENINSULA TO
6.0-6.5C/KM OVER THE ERN GOMEX...BUT H85-H70 LAPSE RATES ACTUALLY
DECREASE FROM ARND 5.5C/KM OVERHEAD TO 4.5C/KM UPSTREAM.
TODAY-TONIGHT...
THE ZONAL ORIENTATION OF THE JET WILL MAINTAIN A DEEP W/SW FLOW THRU
THE H85-H30 LYR THAT WILL REMAIN PARALLEL TO THE ORIENTATION OF THE
STATIONARY FRONT. THIS ASSURES THE FRONT WILL NOT MAKE MUCH PROGRESS
S OF THE I-4 CORRIDOR...IF EVEN THAT FAR. RUC40 ANALYSIS CONTINUES
TO SHOW A TIGHT E-W ISENTROPIC GRADIENT THRU THE 300K-315K LYR THAT
WILL COMBINE WITH THE DEEP W/SW FLOW TO EVENTUALLY PRODUCE THE NEXT
RAIN EVENT.
WITH MOST OF THE DRY AIR OVER CENTRAL FL ALREADY ERODED AND
PLENTIFUL MOISTURE UPSTREAM POISED TO PLOW WHAT REMAINS OUT OF THE
WAY...AND A WELL STACKED BAND OF INSTABILITY OVER THE GOMEX...POPS
WILL BE INTRODUCED TO THE ENTIRE CWA...SLGT CHC ALONG AND N OF
THE I-4 CORRIDOR THROUGH EARLY AFTN...BCMG 30-40 FROM VERO BEACH/LAKE
KISSIMMEE NWD. DRIER AIR AND FURTHER DISTANCE FROM THE FRONT WILL
LIMIT PRECIP OVER THE SRN CWA TO 20PCT...MAINLY IN -SHRAS.
PRECIP WILL INCREASE AREAWIDE TONIGHT...BUT AGAIN WILL REFLECT THE
DRIER AIR TO THE S AND THE POSITION OF THE STATIONARY FRONT. PRECIP
PRIMARILY WILL BE AS SHRAS...COOL AIR ALOFT ALONG WITH THE ENHANCED
BAND OF MID/UPR LVL INSTABILITY MAY ALLOW ISOLATED TSRA TO DVLP IN
THE VCNTY OF THE FRONTAL BNDRY. BOTH GFS/ECMWF MOS SHOWS HI POPS
OVER THE NRN CWA...THOUGH ECMWF IS TOO AGGRESSIVE WITH 70POPS CLEAR
DOWN TO LAKE OKEECHOBEE/JUPITER INLET. LIKELY/CATEGORICAL OVER THE
NRN BREVARD/NRN OSCEOLA NWD...SCT FROM SRN BREVARD/SRN OSCEOLA SWD.
ONE FLY IN THE OINTMENT IS THE GFS SOLUTION BTWN 06Z-12Z TONIGHT
WITH QPF BTWN 0.75"-1.5" ALONG THE I-4 CORRIDOR. TIME SECTIONS FOR
THE REGION SHOW VERY STRONG COUPLETS IN THE OMEGA AND DIVERGENCE
FIELDS IN THE PRESENCE OF 90PCT MEAN RH THRU THE ENTIRE H70-H30 LYR.
WHILE THE MOISTURE SOLUTION SEEMS REASONABLE...THE COUPLETS ARE
CLEAR SIGNS OF CONVECTIVE FEEDBACK. PRECIP CHANCES WILL BE HIGH...
NO DOUBT...BUT WILL CAP QPF BTWN 0.25"-0.50".
DESPITE INCREASING CLOUD COVER...LIGHT SRLY WINDS WILL COMBINE WITH
THE SLOW ARRIVAL OF SIG PRECIP TO ALLOW AFTN TEMPS TO WARM INTO THE
M/N70S AREAWIDE...NEAR 80 ALONG THE NE SHORE OF LAKE OKEECHOBEE...
4-8F ABV AVG. CLDY SKIES AND SFC DEWPOINTS IN THE U50S/L60S WILL
KEEP OVERNIGHT MINS IN THE L/M60S...EXCEPT IN THE M/U60S ALONG THE
IMMEDIATE COAST...10-15F ABV AVG.
MON-TUE...A MOIST SOUTHERLY WIND FLOW WILL BE IN PLACE WITH
FRONTAL BOUNDARY JUST TO OUR NORTH. TAIL END OF A BAND OF
CONVECTION NEAR THIS FRONTAL BOUNDARY MAY BE AFFECTING NORTHERN
SECTIONS EARLY MON THEN AS THE BOUNDARY GRADUALLY LIFTS NORTH...
NO LARGE SCALE LIFTING MECHANISMS ARE NOTED. LIKELY POPS IN THE
NORTH MON WILL TAPER BACK TO 30-40 PERCENT TUE. POPS ACROSS THE
SOUTH LOOK TO JUST BE AROUND 20 PERCENT BOTH DAYS. WITH THE HIGH
MOISTURE...THERE WILL PLENTY OF CLOUDINESS...ESPECIALLY MON. MAX
TEMPS SHOULD BE IN THE MID 70S NORTH ON MON AND LOWER 80S SOUTH.
THE LOWER 80S SHOULD LIFT TO CENTRAL SECTIONS ON TUE.
TUE NIGHT-CHRISTMAS...TROUGH IN THE MID SECTION OF THE COUNTRY
WILL DEEPEN WITH BASED DIGGING INTO THE GULF OF MEXICO WED THEN
DAMPENING OUT AS IT LIFTS ACROSS THE SOUTHEAST STATES ON CHRISTMAS.
THIS LATEST MODEL SOLUTION IS SLOWER THAN PREVIOUS RUNS...SO HAVE
BACKED OFF ON PRE FRONTAL CONVECTION UNTIL LATE TUE NIGHT IN THE
NORTH AND ON WED FOR THE REST OF THE AREA. RATHER STRONG LOW LEVEL
WINDS ARE STILL INDICATED AS THE CONVECTIVE BAND MOVES ACROSS THE
AREA. THE ECMWF 850 MB WINDS ARE STRONGER THAN THE GFS (WHICH HAS
BACKED TO AROUND 35 KNOTS). IN ANY EVENT...WITH THE SLOWER
SOLUTION...MODEST DIURNAL HEATING/DESTABILIZATION ON WED COULD
LEAD TO SOME STRONG STORMS.
SHOWER CHANCES MAY LINGER INTO WED NIGHT AND SOME CLOUDINESS INTO
CHRISTMAS MORNING. TEMPS DO NOT LOOK AS COOL WITH THE SLOWER
FRONTAL PASSAGE AND SOME CLOUDINESS. CONSENSUS LOWS ARE NOW IN THE
LOWER/MID 50S WITH HIGHS CHRISTMAS DAY IN THE MID 60S TO LOWER
70S...AND THESE READINGS MAY EVEN BE TOO COOL.
FRI-NEXT SUNDAY...HIGH PRESSURE BEHIND THE COLD FRONT IS FORECAST TO
EXTEND ACROSS THE AREA FRI AND ELONGATE INTO THE ATLANTIC NEXT
WEEKEND. THE MODELS DISAGREE ON TIMING OF THE NEXT COLD FRONT WITH
CONSENSUS SOLUTION SHOWING IT APPROACHING BY SUN (MOST SUPPORTED
BY THE ECMWF). THE GFS SMEARS 15-20 POPS OUT SAT-SUN BUT WILL HOLD
OFF THROWING IN 20 PERCENT UNTIL SUNDAY. AFTER TEMPS CLOSE TO
NORMAL ON FRI...MODERATION TO A LITTLE ABOVE NORMAL IS EXPECTED ON
THE WEEKEND.
&&
.AVIATION...THRU 22/06Z
SFC WNDS:
THRU 21/15Z...VRBL AOB 4KTS. BTWN 21/15Z-21/18Z...S 5-8KTS. BTWN
21/18Z-21/22Z...INTERIOR SITES S/SW 4-7KTS...COASTAL SITES S/SE
6-9KTS. AFT 21/22Z...S/SE AOB 5KTS.
VSBYS:
THRU 21/14Z...AREAS MVFR IN BR...LCL LIFR IN FG MNLY VCNTY
KVRB/KFPR. BTWN 21/14Z-21/18Z...N OF KEVB-KISM SLGT CHC MVFR SHRAS.
BTWN 21/18Z-22/03Z...N OF KMLB-KLAL SCT MVFR/ISOLD IFR SHRAS...S OF
KMLB-KLAL SLGT CHC MVFR SHRAS. AFT 22/03Z...N OF KTIX-KISM
PREVAILING MVFR IN NMRS/WDSPRD RA WITH PDS IFR +RA...S OF KTIX-KISM
CHC MVFR SHRAS.
CIGS:
N OF KMLB-KLAL: THRU 21/14Z...BTWN FL080-100 WITH PDS MVFR BTWN
FL020-030. BTWN 21/14Z-22/03Z...BTWN FL060-080 WITH PDS MVFR BTWN
FL015-025 IN SCT SHRAS. AFT 22/03Z...MVFR BTWN FL010-020.
S OF KMLB-KLAL: THRU 21/14Z...AOA FL120. BTWN 21/14Z-22/03Z...BTWN
FL080-100 WITH PDS MVFR BTWN FL020-030 IN ISOLD -SHRAS. AFT
22/03Z...BTWN FL060-080 WITH PDS MVFR BTWN FL015-025 IN SCT -SHRAS.
&&
.MARINE...
TODAY-TONIGHT...FAVORABLE SEA CONDS THRU DAYBREAK BUT DETERIORATING
WX CONDS AS A WEAK STATIONARY FRONT JUST N OF THE I-4 CORRIDOR
KEEPS THE LCL PGRAD DISRUPTED AND SERVES AS A FOCUS FOR SHRA/TSRA
ACTIVITY. SFC WNDS S-SE BTWN 4-8KTS FROM CAPE CANAVERAL SWD...VRBL
AOB 5KTS N OF THE CAPE IN THE VCNTY OF THE FRONT. SEAS AOB 2FT...
BUILDING TO 2-3FT OVER THE OFFSHORE LEG AFT MIDDAY.
N OF THE CAPE...SCT SHRAS AFT MIDDAY...BCMG NMRS/WDSPRD WITH ISOLD
TSRAS AFT SUNSET. S OF THE CAPE...ISOLD/SCT SHRAS AFT MIDDAY...CONTG
THRU THE OVERNIGHT PD.
MON-WED...SOUTHERLY FLOW WITH 10-15 KNOT SPEEDS INDICATED MON THEN
PUSHING UP TO 15-20 KNOTS TUE AFTERNOON AND EVENING AND NEAR 20
KNOTS WED AS COLD FRONT APPROACHES. SHOWER AND STORM CHANCES MAY
BE 50-60 PERCENT IN THE NORTH MON...THEN DROP OFF TO 20-40 PERCENT
UNTIL FRONTAL BAND CONVECTION APPROACHES LATE TUE NIGHT AND ON WED.
CHRISTMAS...STILL A LITTLE BIT OF A TRICKY FORECAST AS THE GFS IS
A LITTLE SLOWER THAN THE ECMWF WITH THE TIMING OF FRONTAL PASSAGE.
IF THE FRONT IS SLOWER LIKE THE GFS...THE BAND OF SHOWERS/STORMS
MAY STILL BE ACROSS THE WATERS EARLY...BUT OTHERWISE A NORTHWEST
WIND SURGE 15-20 KNOTS IS INDICATED BEHIND THE FRONT...SO BOATING
CONDITIONS DO NOT LOOK GOOD WITH EITHER MODEL.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 74 66 76 65 / 40 80 60 40
MCO 77 64 77 64 / 40 70 50 30
MLB 77 67 77 67 / 30 40 40 20
VRB 77 68 79 66 / 20 30 30 20
LEE 76 63 76 64 / 40 80 60 40
SFB 76 63 76 64 / 40 80 60 30
ORL 76 64 76 65 / 40 70 50 30
FPR 77 69 80 66 / 20 30 30 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM...BRAGAW
LONG TERM....LASCODY
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
310 AM EST SUN DEC 21 2014
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A CURRENTLY UNAMPLIFIED
UPPER LEVEL PATTERN ACROSS THE CONUS. FLOW IS MAINLY ZONAL ALONG THE
EASTERN SEABOARD DOWN TO THE FLORIDA PENINSULA...BUT WATCHING A
BROAD UPSTREAM TROUGH EJECTING EASTWARD ACROSS THE SOUTHERN PLAINS.
ENERGY FROM THE BASE OF THIS TROUGH WILL QUICKLY MOVE EASTWARD
ACROSS THE NORTHERN GULF COAST DURING THE NEXT 24 HOURS AND INTERACT
WITH A SURFACE FRONT ACROSS THE SAME REGION TO BRING INCREASING RAIN
CHANCES TO THE CENTRAL AND NORTHERN FLORIDA PENINSULA. HOWEVER...FOR
MOST OF US...THAT WILL NOT BE UNTIL MUCH LATER TODAY OR
TONIGHT...AND WILL DISCUSS IN MORE DETAIL WITHIN THE SHORT TERM
SECTION BELOW.
FURTHER UPSTREAM WE SEE STRONG UPPER JET ENERGY ARRIVING OVER THE
PACIFIC NORTHWEST COAST. IT WILL BE THIS ENERGY THAT EVOLVES INTO A
SIGNIFICANT PATTERN AMPLIFICATION/DEEP TROUGH THROUGH THE CENTRAL
PORTION OF THE COUNTY BY TUESDAY. IN RESPONSE TO THIS AMPLIFYING
TROUGH...THE DOWNSTREAM RIDGE OVER THE WESTERN ATLANTIC IS ALSO
PROGGED TO UNDERGO A SIGNIFICANT AMPLIFICATION. NEEDLESS TO
SAY...THE UPPER LEVEL PATTERN WILL HAVE LITTLE RESEMBLANCE TO THIS
MORNING WITHIN ONLY A COUPLE SHORT DAYS.
LOWER LEVELS...A QUASI-STATIONARY SURFACE FRONTAL BOUNDARY IS
LOCATED FROM THE CENTRAL GULF OF MEXICO NORTHEASTWARD TO THE
NORTHERN FLORIDA PENINSULA. RETURN FLOW IN THE LOWER LEVELS FROM THE
SOUTH IS DEVELOPING IN RESPONSE TO THE APPROACH OF THE UPPER WAVE TO
THE WEST. THIS FLOW IS BEGINNING TO UNDERGO ISENTROPIC UPGLIDE ALONG
THE 295-305K SURFACES...AND WE CAN SEE MORE AND MORE LOWER/MID LEVEL
CLOUDS BREAKING OUT ACROSS THE EASTERN GULF AND FL PENINSULA THIS
MORNING. THIS UPGLIDE HAS BEEN MAXIMIZED TO THE NORTH OF THE FRONT
ALONG WITH DECENT SURFACE FOCUS. REGIONAL RADAR HAVE BEEN SHOWING
AREAS OF SHOWERS DEVELOPING ACROSS THE FL PANHANDLE/NE GULF AS A
RESULT. SO FAR...MUCH OF THIS ACTIVITY HAS BEEN REMAINING TO OUR
NORTH...BUT WILL SEE A TENDENCY FOR THE SHOWERS TO MIGRATE TOWARD
THE NATURE COAST AS WE HEAD THROUGH THE DAY.
&&
.SHORT TERM (TODAY THROUGH MONDAY)...
MUCH OF THE FORECAST AREA WILL SEE A DRY MORNING AS ATMOSPHERIC
MOISTENING AS A RESULT OF LARGE SCALE UPGLIDE WILL BE SLOW TO
OCCUR...AND ANY ADDED SURFACE CONVERGENCE AS A RESULT OF SURFACE
WARM FRONT WILL BE CONFINED TO OUR FAR NORTHERN ZONES. WILL BRING A
LOW SHOWER CHANCE INTO LEVY/CITRUS COUNTIES THIS MORNING...BUT
ELSEWHERE POPS WILL BE 10% OR LESS. SKIES WILL BE MOSTLY
CLOUDY...ALTHOUGH BETTER CHANCES FOR PERIODS OF SUN WILL EXIST SOUTH
OF THE TAMPA BAY REGION. APPROACHING UPPER LEVEL ENERGY WILL
INCREASE ITS INTERACTION WITH THE SURFACE BOUNDARY DURING THE SECOND
HALF OF THE DAY...AND ESPECIALLY INTO THE EVENING HOURS. SURFACE
PRESSURE PATTERN WILL SHARPEN ACROSS THE NORTHEAST GULF OF MEXICO
INCREASING THE LOW LEVEL CONVERGENCE/FOCUS...AND BY LATE IN THE
DAY...THIS SHOULD COMBINE WITH CONTINUED UPGLIDE AND A DEVELOPING
FAVORABLE RRQ COUPLED JET PATTERN ALOFT TO PRODUCE INCREASING
SHOWERS COVERAGE INTO THE NATURE COAST ZONES. NWP ENSEMBLE MEMBERS
ARE NOT IN COMPLETE AGREEMENT WITH THE PLACEMENT OF THE LIFTING
FEATURES...AND THEREFORE HAVE SOMEWHAT DIFFERENT QPF PATTERNS. THE
NAM CONTINUE TO BE FURTHEST NORTH WITH THE BEST LIFT...WHILE THE
GFS...AND ESPECIALLY THE ECMWF SHOW BETTER SHOWER COVERAGE SOUTHWARD
INTO WEST-CENTRAL FLORIDA. THE NEW 21/03Z SREF ENSEMBLE MEAN HAS
TRENDED TOWARD THE GLOBAL MODELS WITH DECENT QPF NOW DOWN TO THE I-4
CORRIDOR. SO...AS SEEMS TO OFTEN BE THE CASE...THE MOST UNCERTAINTY
IN THE RAIN PROBABILITY FORECAST LATE TODAY INTO TONIGHT WILL BE
THROUGH THE TAMPA BAY/I-4 CORRIDOR...AND THE TIGHTEST POP GRADIENT
WILL BE ACROSS THIS REGION. WILL HAVE HIGH END LIKELY TO CATEGORICAL
POPS ANYWHERE NORTH OF I-4...WITH LIKELY POPS THROUGH THE TAMPA BAY
REGION...AND THEN QUICKLY DECREASE RAIN CHANCES FURTHER SOUTH AND
SOUTHEAST. WITH RESPECT TO THE ECMWF/GFS HAVE GONE WITH A 30-40%
CHANCE NEAR THE COAST DOWN TO SARASOTA/CHARLOTTE COUNTIES.
THE PLACEMENT OF THE UPPER JET IS MOST FAVORABLE FOR SIGNIFICANT
UPPER DIVERGENCE OVER THE NORTHERN HALF OF THE REGION TONIGHT. THE
GFS DIVERGENCE FIELDS ARE ACTUALLY QUITE IMPRESSIVE. MANY OF THE
MODELS SEEM TO BE PICKING UP ON THIS AND RAMPING UP QPF AMOUNTS
DURING THE OVERNIGHT HOURS. THEREFORE...THE POTENTIAL DOES APPEAR TO
EXIST FOR SOME PERIODS OF HEAVIER RAINFALL AFTER 00Z FROM TAMPA BAY
NORTHWARD THROUGH THE NATURE COAST. DUE TO THE INCREASED SYNOPTIC
LIFT IN THIS REGION (NORTH OF I-4) AND SHOWALTER INDICES AT OR BELOW
ZERO HAVE ADDED IN ISOLATED THUNDER TO THE FORECAST FOR ELEVATED
CONVECTION.
MONDAY...
EARLY MONDAY MORNING LOOKS TO BE JUST A CONTINUATION OF THE FORECAST
FROM TONIGHT...HOWEVER AS THE MORNING PROGRESSES WE SEE NOT ONLY THE
UPPER JET POSITION BECOME LESS FAVORABLE...BUT ALSO APPEARS THE LOW
LEVEL FRONT WILL BEGIN TO MOVE NORTHWARD AS A WARM FRONTAL FEATURE
AND REACH AT LEAST THE I-10 CORRIDOR BY EARLY AFTERNOON. THE LOSS OF
LARGE SCALE LIFT AND A DECREASE IN SURFACE FOCUS SHOULD RESULT IN
AREAS OF SHOWERS BECOME LESS ORGANIZED AND LIGHTER IN NATURE. RAMP
DOWN RAIN CHANCES THROUGH THE DAY...AND REMOVE ALL MENTION OF LIKELY
POPS (EVEN FOR THE NATURE COAST) BY THE AFTERNOON HOURS. RAIN
CHANCES ARE ACTUALLY LOOKING LESS AND LESS AS TIME GOES ALONG SOUTH
OF TAMPA BAY FOR MONDAY. IF WE CAN GET ENOUGH SUN TO BREAK
THROUGH THE CLOUDS...THE ATMOSPHERIC TEMP POTENTIAL IS GOING TO BE
VERY HIGH AND AFTERNOON HIGHS FOR THE SOUTHERN HALF OF THE FORECAST
AREA IN THE 80S MAY BECOME WIDESPREAD. TEMPS ARE MORE LIKELY TO BE
HELD IN THE 70S FROM TAMPA BAY NORTHWARD DUE TO MORE SHOWER AND
CLOUD POTENTIAL LATER INTO THE DAY.
&&
.LONG TERM (TUESDAY THROUGH NEXT SUNDAY)...
MODELS IN FAIRLY GOOD AGREEMENT THROUGH THE PERIOD. ONE UPPER
LOW/LONG WAVE TROUGH INITIALLY OVER THE MID CONUS MOVES EAST AND OFF
THE EASTERN SEABOARD BY THE END OF THE WEEK WITH A COLD FRONT
TRACKING INTO THE EASTERN GULF TUE THEN CROSSING FL WED. FOR THU
INTO SAT...RIDGING ALOFT AND SURFACE BUILDS INTO THE GULF AND SHIFTS
OVER THE STATE TO ATLANTIC WATERS. DURING SAT A SECOND LONG WAVE
TROUGH...A BIT LESS ROBUST THIS TIME...SLIDES FROM THE
MID-MISSISSIPPI VALLEY TO THE EAST STATES BY SUN WITH A COLD FRONT
SAGGING INTO FL.
THE UPPER TROUGH AMPLIFIES WITH INCREASING DEEP MOISTURE AS IT MOVES
ACROSS THE GULF THEN FL TUE AND WED. EXPECT AREAS OF SEA FOG TO
SPREAD SOUTHWARD DURING TUE...AND POSSIBLY BECOME LOCALLY DENSE...AS
LARGE AREAS OF CONVECTION MOVE ACROSS FROM NORTHWEST TO SOUTHEAST.
THERE WILL BE THE POTENTIAL FOR A FEW STRONG TO POSSIBLY SEVERE
STORMS. THE BULK OF THE CONVECTION WILL EXIT TO THE EAST WED
AFTERNOON AND EVENING. COOLER DRIER AIR WORKS IN DURING THU AND FRI
AS THE RIDGING MOVES BY. AS NOTED ABOVE THE NEXT UPPER TROUGH IS
WEAKER AND WILL HAVE LESS MOISTURE TO WORK WITH SO ONLY SLIGHT
CHANCE SHOWERS ARE EXPECTED...ACROSS THE NORTH SAT THEN SPREADING
INTO CENTRAL COUNTIES SUN. TEMPERATURES START OFF ABOVE NORMAL THEN
COOL THROUGH THE LAST PART OF THE WEEK BEFORE WARMING TO AROUND
NORMAL BY SUN. WINDS INCREASE INTO EXERCISE CAUTION/ADVISORY SPEEDS
LATE TUE AND WED AS THEY VEER FROM SOUTH TO WEST AND NORTH BEHIND
THE FRONT. WINDS DIMINISH DURING THU.
&&
.AVIATION...
GENERAL VFR CONDITIONS EARLY THIS MORNING UNDER PLENTY OF MID-LEVEL
CLOUDS. ALTHOUGH GUIDANCE IS HINTING OUT SOME FOG POTENTIAL FOR
KLAL/KPGD...THINKING THE CURRENT CLOUDS WILL PREVENT MUCH IN THE WAY
OF VIS RESTRICTIONS. GENERAL VFR CONDITIONS SHOULD PREVAIL THROUGH
THE DAYLIGHT HOURS WITH A LIGHT SOUTHEAST WIND SHIFTING SOUTH IN THE
AFTERNOON. PROBABILITY FOR SHOWERS WILL BE INCREASING DURING THE
LATE AFTERNOON AND EVENING HOURS FOR MAINLY KSRQ TO KTPA AND KLAL.
THE SHOWERS AND LOWER CLOUDS MAY RESULT IN PERIODS OF MVFR
RESTRICTIONS THROUGH THE OVERNIGHT HOURS INTO EARLY MONDAY MORNING.
&&
.MARINE...
A STATIONARY FRONTAL BOUNDARY IS LOCATED ACROSS THE NORTHERN
WATERS...JUST TO THE SOUTH OF CEDAR KEY EARLY THIS MORNING. WINDS
ARE EAST TO SOUTHEAST SOUTH OF THIS BOUNDARY AND FROM THE NORTHEAST
ON ITS NORTHERN SIDE. AREAS OF SHOWERS/RAIN EXPECTED TO INCREASE IN
COVERAGE OF THE MARINE AREA TO THE NORTH AND WEST OF TAMPA BAY
TODAY...SHOWERS REACHING FURTHER SOUTH TONIGHT. THE WARM FRONT IS
EXPECTED TO LIFT NORTH OF THE FORECAST WATERS FOR MONDAY WITH
SOUTHERLY FLOW HOLDING IN PLACE UNTIL A COLD FRONT CROSSES THE
REGION SOMETIME ON WEDNESDAY. WINDS WILL SHIFT NORTHWEST LATER
WEDNESDAY AND WEDNESDAY NIGHT AND POSSIBLY INCREASE TO ADVISORY
LEVELS FOR A TIME. WINDS AND SEAS QUICKLY DECREASE THURSDAY AND
FRIDAY AS HIGH PRESSURE BUILDS OVER THE REGION.
DEEP SOUTHERLY FLOW IS EXPECTED TO BRING CONDITIONS FAVORABLE FOR
SEA FOG TO DEVELOP IN THE NEXT SEVERAL DAYS. PATCHY FOG IS POSSIBLE
AS EARLY AS MONDAY...ESPECIALLY NORTH OF TARPON SPRINGS...HOWEVER...
THE SEA FOG IS ANTICIPATED TO BECOME MORE WIDESPREAD...AND EXTEND
FURTHER SOUTH MONDAY NIGHT INTO TUESDAY. ONCE FOG DEVELOPS IT IS
LIKELY TO LINGER INTO WEDNESDAY MORNING BEFORE A COLD FRONTAL
PASSAGE FINALLY CLEARS THE AREA. THE FOG IS ALSO ANTICIPATED TO
BECOME LOCALLY DENSE AT TIMES...ESPECIALLY TUESDAY AND TUESDAY
NIGHT.
&&
.FIRE WEATHER...
NO SIGNIFICANT FIRE WEATHER CONCERNS EXPECTED THROUGH MONDAY.
WETTING RAINFALL IS EXPECTED FROM TAMPA BAY NORTHWARD TONIGHT AND
MONDAY...WITH MORE SCATTERED NATURE SHOWERS FURTHER SOUTH. ANOTHER
ROUND OF WETTING RAINFALL FOR ALL ZONES IS EXPECTED LATER TUESDAY
NIGHT INTO WEDNESDAY WITH THE PASSAGE OF A COLD FRONT. DRIER WEATHER
WILL THEN RETURN FOR THURSDAY AND FRIDAY. LOCATIONS NEAR THE COAST
ARE ANTICIPATED TO SEE AREAS OF SEA FOG MOVE ASHORE...ESPECIALLY
TUESDAY INTO EARLY WEDNESDAY. THE FOG MAY BECOME LOCALLY DENSE AT
TIMES WITHIN A FEW MILES OF THE COAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 77 66 76 66 / 40 70 50 20
FMY 80 65 78 66 / 20 20 10 20
GIF 79 64 77 64 / 40 60 50 20
SRQ 77 65 76 65 / 30 50 40 20
BKV 77 64 77 64 / 50 80 70 30
SPG 76 65 74 66 / 40 70 50 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WX...MROCZKA
LONG TERM...RUDE
AREA FORECAST DISCUSSION
NWS BOISE ID
927 AM MST SUN DEC 21 2014
.DISCUSSION...RAIN AND SNOW CONTINUE IN IDAHO ZONES NORTH OF THE
SNAKE BASIN THIS MORNING BUT IT HAS DECREASED IN OREGON AND SWRN
IDAHO. MORE PCPN UPSTREAM WHICH MODELS BRING IN MID-DAY THROUGH
TONIGHT. SNOW CHANGED TO RAIN AT MCCALL AROUND 330 AM MST AND
OUR ENTIRE CWA BELOW 6000 FEET WILL HAVE RAIN RATHER THAN SNOW
THROUGH MID-AFTERNOON. SNOW LEVEL WILL SLOWLY LOWER THS AFTERNOON
AND TONIGHT AS UPPER WINDS CHANGE FROM WESTERLY TO NWLY. TEMPS
WILL COOL DOWN WITH HIGHS MONDAY ABOUT 10F LOWER THAN TODAY. WIND
ADVISORY WILL CONTINUE IN OUR SRN ZONES THROUGH THE DAY. 12Z BOI
RAOB HAD VERY STRONG WESTERLY WINDS ALOFT. AVALANCHE WARNING
STILL IN EFFECT IN THE SAWTOOTH RECREATION AREA THROUGH AT LEAST
700 AM MONDAY. GENERAL TREND THROUGHOUT OUR CWA IS COOLER AND
DRIER TONIGHT THROUGH MONDAY. DRY THROUGH WEDNESDAY THEN COLDER
WITH A CHANCE OF SNOW WEDNESDAY NIGHT. CHANCE OF LIGHT SNOW C
RISTMAS DAY...THEN DRY AND COLD THROUGH SATURDAY. NO UPDATES AT
THIS TIME.
&&
.AVIATION...WIDESPREAD MVFR-IFR CONDITIONS WITH PRECIPITATION.
MOUNTAINS OBSCURED. SNOW LEVELS AT THE SURFACE IN CENTRAL IDAHO
MOUNTAINS RANGING UP TO 10K FEET MSL SW OF THE SNAKE RIVER PLAIN.
SNOW LEVELS WILL SLOWLY FALL FROM NORTH TO SOUTH AS PRECIPITATION
BAND MOVES SOUTHWARD TODAY AND TONIGHT. VFR CONDITIONS SOUTH AND
WEST OF A LINE FROM KBNO-KREO IN SE OREGON. SURFACE WINDS WESTERLY
15-25KT WITH GUSTS TO 45KT THIS AFTERNOON IN SE OREGON AND EASTERN
MAGIC VALLEY EAST OF KJER...NORTHWESTERLY SURFACE WINDS UP TO 15KT
ELSEWHERE. WINDS ALOFT AROUND 10K FT MSL...NW 50-75KT DIMINISHING TO
NW 35-50KT BY 12Z MON.
&&
.PREV DISCUSSION...
SHORT TERM...TODAY THROUGH MONDAY...THE WARM FRONT IS FINALLY
SHOWING SIGNS OF PUNCHING NORTHWARD AS THE MODELS HAVE PROMISED.
BOGUS BASIN IS ABOVE FREEZING AND THE WEB CAM INDICATES RAIN. KMYL
IS STILL SNOWING...BUT SHOULD CHANGE TO RAIN SHORTLY. THE WSW WILL
BE ALLOWED TO EXPIRE AT 3 AM WITH THE MORNING FORECAST PACKAGE.
LIGHT TO MODERATE RAIN IS STILL FALLING OVER MOST OF THE REGION...
AND WE EXPECT IT TO CONTINUE FOR MUCH OF TODAY AS A WARM MOIST
FLOW REMAINS ENTRENCHED ALOFT. LATEST HRRR MODEL INDICATES A BREAK
THIS MORNING IN THE LOWER TREASURE VALLEY AND WESTERN PORTIONS OF
THE UPPER TREASURE VALLEY...INCLUDING BOISE. BUT THEN PRECIP
SPREADS BACK INTO THESE AREAS THIS AFTERNOON. THIS WILL HAVE A
STRONG IMPACT ON TEMPERATURES TODAY. WE HAVE LOWERED THE FORECAST
FOR THESE AREAS DUE TO HIGH-RESOLUTION MODEL DATA INDICATING
LESS WARMING THAN PREVIOUSLY EXPECTED TODAY. AS WE MOVE INTO
TONIGHT...SNOW LEVELS MOVE BACK DOWN AND MOISTURE WILL FINALLY
BEGIN TO DECREASE. THE CHANCE OF PRECIP DECREASES SHARPLY MONDAY
AND TEMPS WILL COOL FURTHER. WINDS WILL BE STRONG TODAY IN SE
OREGON...THE SOUTHWEST HIGHLANDS OF IDAHO...AND THE HIGHER TERRAIN
OF SRN TWIN FALLS COUNTY. THE WIND ADVISORY IS STILL ON TRACK TO GO
INTO EFFECT AT 8 AM MST AND RUN UNTIL 5 PM MST.
LONG TERM...MONDAY NIGHT THROUGH SATURDAY...CONDITIONS ARE
EXPECTED TO CONTINUE TO DRY OUT MONDAY NIGHT AND TUESDAY AS A
RIDGE OFF OF THE CALIFORNIA COAST AMPLIFIES. THIS WILL KEEP
TEMPERATURES ABOVE NORMAL. MODELS ARE IN GOOD AGREEMENT OF THE
RIDGE STARTING TO FLATTEN OUT ON WEDNESDAY AHEAD OF A TROUGH
MOVING IN FROM COASTAL BRITISH COLUMBIA. THE LATEST GFS AND ECMWF
RUNS HAVE BEGUN TO AGREE ON TIMING OF THIS TROUGH AND ASSOCIATED
COLD FRONT. PRECIP CHANCES WILL SPREAD FROM NW TO SE LATE WED
NIGHT WITH SNOW LEVELS AROUND 5000 FT DROPPING TO 2000 FT BY
EARLY CHRISTMAS MORNING. HOWEVER...THIS SYSTEM WILL LIKELY MOVE
OUT OF THE AREA QUITE QUICKLY SO CONDITIONS SHOULD DRY OUT ONCE
AGAIN CHRISTMAS AFTERNOON/EVENING. THE ASSOCIATED COLD FRONT WILL
BRING TEMPERATURES BACK TO NEAR NORMAL FOR THE REST OF THE PERIOD.
A COOLER NORTHWEST FLOW WILL SET IN FOR FRIDAY AND BEYOND.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WIND ADVISORY UNTIL 5 PM MST THIS AFTERNOON IDZ015-029-030.
AVALANCHE WARNING IN THE SAWTOOTH RECREATION AREA UNTIL 730 AM
MST MONDAY.
OR...WIND ADVISORY UNTIL 5 PM MST /4 PM PST/ THIS AFTERNOON ORZ061-063.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...LC
AVIATION.....KA
PREV SHORT TERM...SP
PREV LONG TERM....EP
AREA FORECAST DISCUSSION
NWS BOISE ID
241 AM MST SUN DEC 21 2014
.SHORT TERM...TODAY THROUGH MONDAY...THE WARM FRONT IS FINALLY
SHOWING SIGNS OF PUNCHING NORTHWARD AS THE MODELS HAVE PROMISED.
BOGUS BASIN IS ABOVE FREEZING AND THE WEB CAM INDICATES RAIN. KMYL
IS STILL SNOWING...BUT SHOULD CHANGE TO RAIN SHORTLY. THE WSW WILL
BE ALLOWED TO EXPIRE AT 3 AM WITH THE MORNING FORECAST PACKAGE.
LIGHT TO MODERATE RAIN IS STILL FALLING OVER MOST OF THE REGION...
AND WE EXPECT IT TO CONTINUE FOR MUCH OF TODAY AS A WARM MOIST
FLOW REMAINS ENTRENCHED ALOFT. LATEST HRRR MODEL INDICATES A BREAK
THIS MORNING IN THE LOWER TREASURE VALLEY AND WESTERN PORTIONS OF
THE UPPER TREASURE VALLEY...INCLUDING BOISE. BUT THEN PRECIP
SPREADS BACK INTO THESE AREAS THIS AFTERNOON. THIS WILL HAVE A
STRONG IMPACT ON TEMPERATURES TODAY. WE HAVE LOWERED THE FORECAST
FOR THESE AREAS DUE TO HIGH-RESOLUTION MODEL DATA INDICATING
LESS WARMING THAN PREVIOUSLY EXPECTED TODAY. AS WE MOVE INTO
TONIGHT...SNOW LEVELS MOVE BACK DOWN AND MOISTURE WILL FINALLY
BEGIN TO DECREASE. THE CHANCE OF PRECIP DECREASES SHARPLY MONDAY
AND TEMPS WILL COOL FURTHER. WINDS WILL BE STRONG TODAY IN SE
OREGON...THE SOUTHWEST HIGHLANDS OF IDAHO...AND THE HIGHER TERRAIN
OF SRN TWIN FALLS COUNTY. THE WIND ADVISORY IS STILL ON TRACK TO GO
INTO EFFECT AT 8 AM MST AND RUN UNTIL 5 PM MST.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...CONDITIONS ARE
EXPECTED TO CONTINUE TO DRY OUT MONDAY NIGHT AND TUESDAY AS A
RIDGE OFF OF THE CALIFORNIA COAST AMPLIFIES. THIS WILL KEEP
TEMPERATURES ABOVE NORMAL. MODELS ARE IN GOOD AGREEMENT OF THE
RIDGE STARTING TO FLATTEN OUT ON WEDNESDAY AHEAD OF A TROUGH
MOVING IN FROM COASTAL BRITISH COLUMBIA. THE LATEST GFS AND ECMWF
RUNS HAVE BEGUN TO AGREE ON TIMING OF THIS TROUGH AND ASSOCIATED
COLD FRONT. PRECIP CHANCES WILL SPREAD FROM NW TO SE LATE WED
NIGHT WITH SNOW LEVELS AROUND 5000 FT DROPPING TO 2000 FT BY
EARLY CHRISTMAS MORNING. HOWEVER...THIS SYSTEM WILL LIKELY MOVE
OUT OF THE AREA QUITE QUICKLY SO CONDITIONS SHOULD DRY OUT ONCE
AGAIN CHRISTMAS AFTERNOON/EVENING. THE ASSOCIATED COLD FRONT WILL
BRING TEMPERATURES BACK TO NEAR NORMAL FOR THE REST OF THE PERIOD.
A COOLER NORTHWEST FLOW WILL SET IN FOR FRIDAY AND BEYOND.
&&
.AVIATION...VFR/MVFR CONDITIONS WITH RAIN AND HIGH ELEVATION SNOW
WILL CONTINUE THROUGH THE PERIOD. ISOLATED IFR CONDITIONS AND
MOUNTAIN OBSCURATION STILL EXIST IN THE WEST CENTRAL MOUNTAINS...
BUT AS THOSE AREAS TURN TO RAIN THIS MORNING...EXPECTING SOME
IMPROVEMENT IN VIS/CEILING. SURFACE WINDS WILL BE GENERALLY NW
WITH STRONGER GUSTS IN THE MAGIC VALLEY AND SOUTHWARD...AND
SOUTHEAST OREGON. WINDS ALOFT NEAR 10K FT...NW AT 50-70 KTS.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WIND ADVISORY FROM 8 AM THIS MORNING TO 5 PM MST THIS AFTERNOON
IDZ015-029-030.
WINTER WEATHER ADVISORY UNTIL 3 AM MST EARLY THIS MORNING IDZ011.
OR...WIND ADVISORY FROM 8 AM MST /7 AM PST/ THIS MORNING TO 5 PM MST
/4 PM PST/ THIS AFTERNOON ORZ061-063.
&&
$$
WEATHER.GOV/BOISE
SHORT TERM...SP
LONG TERM....EP
AVIATION.....EP
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
909 PM CST MON DEC 22 2014
.UPDATE...
850 PM CST
NO CHANGES PLANNED TO FORECAST FOR TONIGHT AS UPPER LOW TO OUR
WEST CONTINUES TO DUMBBELL SLOWLY NORTHEAST FROM THE CORN BELT
TOWARD WISCONSIN. ASSOCIATED SFC LOW OVER SOUTHERN IOWA WILL MOVE
NORTHEAST IN CONCERT WITH THE UPPER LOW AND DRAG A WARM FRONT
NORTH ACROSS THE CWA OVERNIGHT INTO EARLY TUESDAY MORNING. THE
RESULT DRIZZLE AND FOG OVERNIGHT PUNCTUATED WITH PERIODS OF RAIN
ALONG WITH SLOWLY RISING TEMPS AS THE DIFFUSE WARM FRONT LIFTS
SLOWLY NORTH. TRENDS IN THE GRIDS ALREADY HAVE A GOOD HANDLE ON
THIS AND NO CHANGES ARE PLANNED.
OF MUCH GREATER CONCERN CONTINUES TO BE THE POTENTIAL FOR A WINTER
STORM AFFECTING PORTIONS OF THE REGION WEDNESDAY...CHRISTMAS EVE
DAY. THE 00Z WRF-NAM IS TRICKLING IN AND APPEARS TO HAVE FINALLY
CAVED IN AND JOINED THE CAMP OF WHAT THE REMAINDER OF THE GLOBAL
MODELS HAD SHOWN ON WITH THE 12Z RUNS. LACK OF RUN-TO-RUN
CONSISTENCY AND HIGH DEGREE OF VARIABILITY BETWEEN VARIOUS MODELS
HAS MADE THIS A CHALLENGING SYSTEM TO FORECAST FOR...HOWEVER THE
12Z GLOBAL MODELS CAME INTO MUCH BETTER AGREEMENT AND NOW THE 00Z
WRF-NAM SEEMS TO HAVE JOINED THAT CAMP WHICH COULD POSE A
SIGNIFICANT WINTER STORM THREAT TO A POTENTIALLY LARGE PORTION OF
OUR CWA WEDNESDAY.
THE EXPLOSIVE DEEPENING OF THE SYSTEM PROGGED IN THE MODELS WITH
500MB...ALONG WITH AMPLE MOISTURE...AND ELEVATED INSTABILITY ALL
LEAVE ME VERY CONCERNED THAT WE COULD BE LOOKING AT A VERY HEAVY
AND WET SNOW AFFECTING THE REGION WEDNESDAY. THE NEGATIVE MID-
LEVEL THETA-E LAPSE RATES AND LAPSE RATES GREATER THAN 6C/KM FROM
600-300MB POINT TOWARD THE POTENTIAL FOR UPRIGHT CONVECTION WITHIN
THE DEFORMATION BAND. THERMAL PROFILES IN THE MODELS ARE MARGINAL
FOR SNOW...ESPECIALLY DOWN LOW...HOWEVER GIVEN THE EXTREMELY
IMPRESSIVE DYNAMICS SHOWN IN THE LATEST GUIDANCE WOULD ANTICIPATE
STRONG ASCENT TO OVERWHELM IN MARGINAL WARMTH DOWN LOW AND LIKELY
ALLOW FOR HEAVY WET SNOW IN THE DEFO BAND.
NOT UNCOMMON FOR RAPIDLY DEEPENING SYSTEMS TO TRACK A BIT FARTHER
WEST THAN MODELS FORECAST...WHICH COULD PUSH THE HEAVY SNOW BAND
FARTHER WEST IN OUR CWA WITH MORE OF A MIX EAST. THE STRONG
FRONTOGENETIC FORCING AND WEAK INSTABILITY WOULD FAVOR A RATHER
NARROW BUT INTENSE BAND OF PRECIPITATION...MAKING THE PLACEMENT OF
ANY HEAVY SNOW BAND VERY DIFFICULT TO PINPOINT.
AM RELUCTANT TO MAKE ANY WHOLE SALE CHANGES TO THE 4TH PERIOD OF
THE FORECAST ON AN EVEN SHIFT FOLLOWING A QUICK GLANCE AT THE
LATEST NAM...HOWEVER IF THE 00Z GLOBAL GUIDANCE COMES IN LOOKING
SIMILAR TO THEIR 12Z RUNS AND ANYTHING LIKE THE 00Z WRF-NAM THEN
THE MIDNIGHT SHIFT WILL PROBABLY NEED TO CONSIDER WINTER STORM
WATCH FOR AT LEAST PORTIONS OF THE AREA. WHILE IT LOOKS TO BE A
VERY HIGH WATER CONTENT SNOWFALL...THE CONVECTIVE ALLOWING MODELS
ARE SPITTING OUT QPF VALUES THAT COULD SUPPORT 6+ INCHES OF SNOW
EVEN WITH SNOW:LIQUID RATIOS AS LOW AS 7-8:1. WILL UPDATE THE SPS
AND HIT THINGS HARDER IN THAT PRODUCT FOR NOW.
IZZI
&&
.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 03Z...
* PRIMARILY IFR CIGS TONIGHT...PROBABLY LIFTING TO MVFR OR
POSSIBLY VFR TUESDAY AFTERNOON
* PERIODS OF RAIN/DRIZZLE TONIGHT THROUGH EARLY TUESDAY MORNING
IZZI
//DISCUSSION...UPDATED 00Z...
DRIZZLY WITH WAVES OF RAIN TONIGHT INTO EARLY TUESDAY MORNING AS A
WARM FRONT LIFTS NORTH ACROSS THE REGION. IFR CIGS ARE LIKELY TO
DROP TO LIFR TONIGHT AND LINGER INTO TUESDAY MORNING. IN THE WAKE
OF WARM FRONTAL PASSAGE TUESDAY MORNING CIGS WILL LIKELY BEGIN TO
LIFT...MOSTLY LIKELY INTO MVFR RANGE THOUGH SOME GUIDANCE SUGGEST
CIGS UP TO VFR TUESDAY AFTERNOON AND NIGHT. WINDS WILL BECOME
SOUTHERLY BEHIND THE WARM FRONT TUESDAY WITH SOME OCNL GUSTS OF
15-20KT POSSIBLE IN THE AFTERNOON.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM CONFIDENCE IN CIGS THROUGH TONIGHT...DECREASING CONFIDENCE
IN CIGS FORECAST TUESDAY
* MEDIUM-HIGH CONFIDENCE IN PRECIP TRENDS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...RAIN LIKELY...POSSIBLY CHANGING TO HEAVY WET SNOW. IFR
OR LOWER PROBABLE.
THURSDAY...CHANCE OF MVFR CIGS...MAINLY EARLY.
FRIDAY...CHANCE OF MVFR CIGS. STRONG SOUTH WINDS POSSIBLE.
SATURDAY AND SUNDAY...CHANCE OF MVFR CIGS.
IZZI
&&
.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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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
908 PM CST Mon Dec 22 2014
.UPDATE...
ISSUED AT 908 PM CST MON DEC 22 2014
Most of forecast looks ok. However, will have to make some
adjustments to pcpn/pop and possibly low temps tonight. Back edge
of pcpn is on the Miss river and will continue to move northeast
overnight. So will be making minor changes to mentioned items shortly.
&&
.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 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 523 PM CST MON DEC 22 2014
Cloudy skies and pcpn will continue at all TAF sites tonight.
Based on model data and radar trends, looks like pcpn might end
between after midnight and just before morning. When the pcpn
ends, expecting cigs to rise to above 1kft at all sites. However,
vis will remain around 4-5sm with fog. These conditions are
expected to continue into the morning hours. The HRRR model is
showing clearing in the morning moving from southwest to
northeast. Not confident with this, so will just have cigs
increasing to higher MVFR levels...about 2kft and lasting until
end of TAF period. Winds will be southeast to south through the
period at around 10-14kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Auten
SHORT TERM...Barnes
LONG TERM...Bak
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
549 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 00Z...
* IFR/LIFR CIGS THROUGH TUESDAY MORNING...PROBABLY LIFTING TO MVFR
OR POSSIBLY MVFR TUESDAY AFTERNOON
* PERIODS OF RAIN/DRIZZLE TONIGHT THROUGH EARLY TUESDAY MORNING
IZZI
//DISCUSSION...UPDATED 00Z...
DRIZZLY WITH WAVES OF RAIN TONIGHT INTO EARLY TUESDAY MORNING AS A
WARM FRONT LIFTS NORTH ACROSS THE REGION. IFR CIGS ARE LIKELY TO
DROP TO LIFR TONIGHT AND LINGER INTO TUESDAY MORNING. IN THE WAKE
OF WARM FRONTAL PASSAGE TUESDAY MORNING CIGS WILL LIKELY BEGIN TO
LIFT...MOSTLY LIKELY INTO MVFR RANGE THOUGH SOME GUIDANCE SUGGEST
CIGS UP TO VFR TUESDAY AFTERNOON AND NIGHT. WINDS WILL BECOME
SOUTHERLY BEHIND THE WARM FRONT TUESDAY WITH SOME OCNL GUSTS OF
15-20KT POSSIBLE IN THE AFTERNOON.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MEDIUM-HIGH CONFIDENCE IN CIGS THROUGH TONIGHT...DECREASING
CONFIDENCE IN CIGS FORECAST TUESDAY
* MEDIUM-HIGH CONFIDENCE IN PRECIP
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...RAIN LIKELY...POSSIBLY CHANGING TO HEAVY WET SNOW. IFR
OR LOWER PROBABLE.
THURSDAY...CHANCE OF MVFR CIGS...MAINLY EARLY.
FRIDAY...CHANCE OF MVFR CIGS. STRONG SOUTH WINDS POSSIBLE.
SATURDAY AND SUNDAY...CHANCE OF MVFR CIGS.
IZZI
&&
.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
523 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 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 523 PM CST MON DEC 22 2014
Cloudy skies and pcpn will continue at all TAF sites tonight.
Based on model data and radar trends, looks like pcpn might end
between after midnight and just before morning. When the pcpn
ends, expecting cigs to rise to above 1kft at all sites. However,
vis will remain around 4-5sm with fog. These conditions are
expected to continue into the morning hours. The HRRR model is
showing clearing in the morning moving from southwest to
northeast. Not confident with this, so will just have cigs
increasing to higher MVFR levels...about 2kft and lasting until
end of TAF period. Winds will be southeast to south through the
period at around 10-14kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Bak
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
408 PM CST SUN DEC 21 2014
.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 22Z...
* CIGS LOWER TO MVFR AND IFR MONDAY
* RAIN DEVELOPS MIDDAY MONDAY
IZZI
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE IS IN PLACE OVER THE NORTHERN ROCKIES THIS AFTERNOON
AND WILL MOVE ACROSS THE MID MISSOURI VALLEY OVERNIGHT WITH A WARM
FRONT LIFTING ACROSS ILLINOIS THROUGH THE DAY MONDAY. SOUTH WINDS
THIS AFTERNOON WILL TURN MORE SOUTHEASTERLY TONIGHT IN ADVANCE OF
THE FRONTAL BOUNDARY. MODELS HAVE LITTLE CONSISTENCY WITH RESPECT TO
CIG HEIGHTS...SO FOR NOW WILL MAINTAIN PREVIOUSLY ADVERTISED TRENDS
WITH SOME MODELS SHOWING SOME RECOVERY IN CIG HEIGHTS EARLY MONDAY.
HAVE MORE CONFIDENCE IN CIGS LOWERING AGAIN THROUGH THE AFTERNOON
MONDAY WITH IFR SEEMING LIKELY AS THE WARM FRONT LIFTS ACROSS THE
TERMINALS. PRECIP WILL OVERSPREAD THE REGION BY LATE MORNING OR
EARLY AFTERNOON. SOUNDINGS SHOW THE COLUMN COOL ENOUGH TO SUPPORT A
MIX OF RAIN AND SNOW INITIALLY BUT SHOULD FAIRLY QUICKLY WARM ENOUGH
TO BECOME ALL RAIN.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* LOW-MEDIUM CONFIDENCE IN CIGS TONIGHT AND MONDAY
MORNING...MEDIUM CONFIDENCE IN CIGS MONDAY AFTERNOON
* HIGH CONFIDENCE IN WINDS
* MEDIUM-HIGH CONFIDENCE IN PRECIP TIMING.
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...RAIN. MVFR/IFR LIKELY. S-SE WINDS.
TUESDAY...CHANCE OF RAIN AND MVFR/IFR ESPECIALLY EARLY. S-SW WINDS.
WEDNESDAY...CHANCE OF SNOW...POSSIBLY MIXED WITH RAIN EARLY.
MVFR/IFR LIKELY. NW WINDS BECOMING W.
THURSDAY...DRY. MVFR CIGS POSSIBLE EARLY. W WINDS BECOMING SW.
FRIDAY...CHANCE OF RAIN OR SNOW. MVFR POSSIBLE. S WINDS BECOMING W.
SATURDAY...DRY. MAINLY VFR. W WINDS.
RATZER
&&
.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...LMZ740...10 PM SUNDAY TO 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
257 PM CST Sun Dec 21 2014
.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 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1149 AM CST SUN DEC 21 2014
MVFR ceilings prevail at the KILX terminals late this morning:
however, the cloud cover is beginning to erode across east-central
Illinois. 1730z visible satellite imagery shows clearing line from
KPRG to just north of K1H2 and lifting slowly northward. Based on
timing tools and latest HRRR forecast, skies will partially clear
at KCMI between 20z and 21z. Further west, forecast soundings
suggest a continued MVFR overcast through the afternoon before
ceilings gradually improve to VFR this evening in advance of an
approaching storm system. IFR ceilings will develop/spread across
the area between 13z and 16z Mon as rain showers arrive from the
southwest. Winds will be from the S/SE at 10-5kt through the
entire period.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Bak
AVIATION...Barnes
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
140 PM CST SUN DEC 21 2014
.SHORT TERM...
620 AM CST
THE MAIN CONCERNS DURING THIS PERIOD WILL MAINLY BE FOCUSED ON
THE TIMING OF RAINFALL EXPECTED MONDAY AND MONDAY NIGHT.
WARM AIR ADVECTION/ISENTROPIC ASCENT HAS PRODUCED SOME DRIZZLE AND
EVEN SOME OCCASIONAL LIGHT SNOW/FLURRIES ACROSS PORTIONS OF NORTH
CENTRAL ILLINOIS EARLY THIS MORNING. TEMPERATURES ACROSS THE AREA
CONTINUE TO HOLD STEADY EITHER RIGHT AT FREEZING OR A DEGREE OR TWO
BELOW IN SOME AREAS. THEREFORE...THERE WILL CONTINUE TO BE THREAT
FOR SOME MINOR GLAZING ON UNTREATED SURFACES ACROSS PORTIONS OF
NORTH CENTRAL ILLINOIS THROUGH AROUND DAYBREAK.
THEREAFTER...TEMPERATURES SHOULD WARM ABOVE FREEZING...ESSENTIALLY
ENDING THIS THREAT. ASIDE FROM SOME LINGERING PATCHY DRIZZLE THIS
MORNING MOST AREAS WILL BE CLOUDY AGAIN...BUT DRY AS TEMPERATURES
WARM INTO THE UPPER 30S THIS AFTERNOON.
MODEL GUIDANCE CONTINUES TO BE IN FAIRLY GOOD AGREEMENT THROUGH
TUESDAY...WITH AN INITIAL AREA OF LOW PRESSURE TRACKING EASTWARD
FROM THE NORTHERN HIGH PLAINS LATER TODAY...TO THE UPPER MISSISSIPPI
VALLEY BY TUESDAY. THIS STILL WOULD KEEP ALL OF NORTHERN
ILLINOIS/NORTHWESTERN INDIANA IN THE WARM SECTOR THROUGH TUESDAY. IT
THIS SYSTEM LOOKS TO BE A DECENT RAINFALL PRODUCER FOR MUCH OF THE
AREA...WITH THE BEST TIMING BEING MONDAY AFTERNOON THROUGH LATE
MONDAY NIGHT/EARLY TUESDAY MORNING. SEVERAL UPPER LEVEL SHORT WAVE
DISTURBANCES ROTATING THROUGH THE LARGER SCALE UPPER LOW OVER THE
PLAINS...SHOULD RESULT IN WHAT APPEARS TO BE TWO ROUNDS OF
RAINFALL...WITH THE FIRST AROUND THE MONDAY AFTERNOON
TIMEFRAME...AND THE SECOND MONDAY NIGHT. THERE IS A SMALL CHANCE
THAT AS THE PRECIPITATION ONSETS LATE MONDAY MORNING...THAT IT COULD
START AS A MIX OF SLEET AND LIGHT SNOW...GIVEN THE INITIAL COOL
ATMOSPHERIC PROFILE. HOWEVER...WARM AIR ADVECTION WILL QUICKLY WARM
THINGS ENOUGH TO RESULT IN ALL RAIN AREA-WIDE BY EARLY MONDAY
AFTERNOON.
DURING THE DAY ON TUESDAY IT APPEARS THAT WE MAY EXPERIENCE A MID
LEVEL DRY PUNCH...WHICH IF DOES OCCUR WOULD RESULT IN LOW CLOUDS
AND PERHAPS SOME LINGERING DRIZZLE AND LOWER CHANCES OF MUCH
ADDITIONAL RAIN. GIVEN THIS...I HAVE LOWERED POPS A BIT DURING THE DAY
ON TUESDAY. TEMPERATURES ACROSS THE AREA MONDAY NIGHT AND TUESDAY
AS WE REMAIN IN THE WARM SECTOR LOOK TO BE MILD FOR THIS TIME OF
YEAR...WITH 40S EXPECTED.
&&
.LONG TERM...
620 AM CST
TUESDAY NIGHT THROUGH SATURDAY...
FORECAST MODEL SOLUTIONS CONCERNING THE EVOLUTION OF THE SURFACE AND
UPPER LEVEL PATTERN ACROSS THE CENTRAL CONUS FROM TUESDAY NIGHT
THROUGH CHRISTMAS HAVE BECOME MORE DIVERGENT OVER THE PAST COUPLE
RUNS...WITH SEVERAL SOLUTIONS EVEN NOW INDICATING THE POSSIBILITY
OF A MUCH WEAKER SURFACE SYSTEM OVER THE GREAT LAKES INTO
CHRISTMAS EVE DUE TO THE FAILURE OF THE UPPER LEVEL TROUGH
BECOMING NEGATIVELY TILTED OVER THE MISSISSIPPI VALLEY...AS MANY
MODELS HAD BEEN PREVIOUSLY ADVERTISING. HOWEVER...GIVEN THIS
SYSTEM IS STILL 3.5 TO 4 DAYS AWAY...I AM HESITANT TO MAKE ANY
MAJOR CHANGES TO THE GOING FORECAST FOR THIS PERIOD...AS IT
APPEARS THE LATEST DETERMINISTIC MODEL SOLUTIONS ARE REALLY JUST
SHOWING US THE INHERENT HIGH AMOUNT OF CHAOS IN THE SYSTEM WITH
SUCH A RAPIDLY CHANGING PATTERN. AS SUCH...I REALLY HAVE NO
CONFIDENCE IN ANY OF THE LATEST 00 UTC DETERMINISTIC GUIDANCE AND
WOULD PREFER TO SEE ADDITIONAL RUNS OVER THE NEXT DAY OR TWO SHOW
SIMILAR TRENDS BEFORE BEGINNING TO MAKING ANY BIG CHANGES. MY
HUNCH IS WE WILL CONTINUE TO SEE ADJUSTMENTS IN THE DETERMINISTIC
RUNS OVER THE NEXT COUPLE OF DAYS AS THE MODELS ATTEMPT TO RESOLVE
THE EVOLUTION OF THE UPPER LEVEL PATTERN OVER THE CENTRAL CONUS.
FOLLOWING THIS SYSTEM...MODEL GUIDANCE IS INDICATING ANOTHER
DISTURBANCE DIGGING ACROSS THE PLAINS STATE BY THURSDAY...AND THIS
COULD RESULT IN ANOTHER PERIOD OF PRECIPITATION ACROSS PORTIONS OF
THE AREA BY FRIDAY. HOWEVER...UNCERTAINTY WITH THIS STORM IS
EXTREMELY HIGH...GIVEN THAT THE ACTUAL EVOLUTION OF THE FIRST STORM
SYSTEM WILL NEED TO BE IRONED OUT FIRST.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* PERIODS OF MVFR CIGS THROUGH TONIGHT...THEN INCREASING CHANCES
FOR CIGS LOWERING TO IFR THROUGH THE AFTERNOON MONDAY.
* PRIMARILY RAIN OVERSPREADING TERMINALS MONDAY AFTERNOON...THOUGH
A WINTRY MIX IS POSSIBLE NEAR THE ONSET.
BMD
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE IS IN PLACE OVER THE NORTHERN ROCKIES THIS AFTERNOON
AND WILL MOVE ACROSS THE MID MISSOURI VALLEY OVERNIGHT WITH A WARM
FRONT LIFTING ACROSS ILLINOIS THROUGH THE DAY MONDAY. SOUTH WINDS
THIS AFTERNOON WILL TURN MORE SOUTHEASTERLY TONIGHT IN ADVANCE OF
THE FRONTAL BOUNDARY. MODELS HAVE LITTLE CONSISTENCY WITH RESPECT TO
CIG HEIGHTS...SO FOR NOW WILL MAINTAIN PREVIOUSLY ADVERTISED TRENDS
WITH SOME MODELS SHOWING SOME RECOVERY IN CIG HEIGHTS EARLY MONDAY.
HAVE MORE CONFIDENCE IN CIGS LOWERING AGAIN THROUGH THE AFTERNOON
MONDAY WITH IFR SEEMING LIKELY AS THE WARM FRONT LIFTS ACROSS THE
TERMINALS. PRECIP WILL OVERSPREAD THE REGION BY LATE MORNING OR
EARLY AFTERNOON. SOUNDINGS SHOW THE COLUMN COOL ENOUGH TO SUPPORT A
MIX OF RAIN AND SNOW INITIALLY BUT SHOULD FAIRLY QUICKLY WARM ENOUGH
TO BECOME ALL RAIN.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* LOW CONFIDENCE IN CIGS REST OF TODAY AND TONIGHT...MEDIUM
CONFIDENCE IN CIGS LOWERING TO IFR MONDAY AFTERNOON.
* MEDIUM-HIGH CONFIDENCE IN WIND DIRECTION...MEDIUM IN SPEEDS.
* MEDIUM CONFIDENCE IN PRECIP TIMING. LOW-MEDIUM IN PRECIP TYPE
INITIALLY BUT HIGH CONFIDENCE IN EVENTUALLY BECOMING ALL RAIN.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...RAIN. MVFR/IFR LIKELY. S-SE WINDS.
TUESDAY...CHANCE OF RAIN AND MVFR/IFR ESPECIALLY EARLY. S-SW WINDS.
WEDNESDAY...CHANCE OF SNOW...POSSIBLY MIXED WITH RAIN EARLY.
MVFR/IFR LIKELY. NW WINDS BECOMING W.
THURSDAY...DRY. MVFR CIGS POSSIBLE EARLY. W WINDS BECOMING SW.
FRIDAY...CHANCE OF RAIN OR SNOW. MVFR POSSIBLE. S WINDS BECOMING W.
SATURDAY...DRY. MAINLY VFR. W WINDS.
RATZER
&&
.MARINE...
240 AM CST
MAIN MARINE CONCERNS CONTINUE TO FOCUS ON STRENGTHENING
SOUTH-SOUTHEAST WINDS TODAY THROUGH LATE MONDAY...AND POTENTIAL FOR
GUSTY NORTHWEST-WEST WINDS...POSSIBLY GALES...FROM LATE WEDNESDAY
INTO THURSDAY.
SURFACE HIGH PRESSURE RIDGE MOVED EAST OF THE LAKE ON SATURDAY
ALLOWING WINDS TO BECOME SOUTHERLY. THE SURFACE PRESSURE GRADIENT
WILL SLOWLY TIGHTEN ACROSS THE UPPER MIDWEST AND WESTERN LAKES TODAY
AS AN AREA OF LOW PRESSURE MOVES SOUTHEAST FROM THE LEE OF THE
CANADIAN ROCKIES...WITH SOUTH-SOUTHEAST WINDS INCREASING INTO THE
25-30 KT RANGE FROM LATER THIS AFTERNOON INTO MONDAY AS THE LOW
APPROACHES FROM THE NORTHERN PLAINS. THE IS EXPECTED TO OCCLUDE AND
BEING TO FILL LATE MONDAY NIGHT...ALLOWING THE GRADIENT TO WEAKEN
AND WINDS TO DIMINISH EARLY TUESDAY. THE REMNANT SURFACE TROUGH WILL
CROSS THE LAKE LATE TUESDAY NIGHT OR EARLY WEDNESDAY...WITH LIGHT
WINDS SHIFTING TO THE WEST-NORTHWEST.
FORECAST MODEL SOLUTIONS FOR THE SURFACE PATTERN FROM WEDNESDAY
AFTERNOON THROUGH THURSDAY HAVE BECOME MORE DIVERGENT OVER THE PAST
FEW RUNS...WITH QUITE A SPREAD IN THE LOCATION TRACK AND DEPTH OF A
SECOND SURFACE LOW WHICH IS EXPECTED TO DEVELOP SOMEWHERE ACROSS THE
OHIO OR TENNESSEE RIVER VALLEYS. OVERALL...GUIDANCE INDICATING A
WEAKER LOW DURING THIS PERIOD...THOUGH MODELS ARE OBVIOUSLY
STRUGGLING WITH DEVELOPMENT OF DIGGING SOUTHERN STREAM JET STREAK
AND THE RESULTING UPPER TROUGH AND DOWNSTREAM SURFACE LOW
DEVELOPMENT. WITH SUCH DIVERGENT SOLUTIONS HAVE AVOIDED MAKING LARGE
SWINGS IN THE FORECAST...AND HAVE HELD ON TO THE GENERAL SCENARIO OF
PREVIOUS FORECAST...THOUGH WITH SLIGHTLY WEAKER WIND FIELD DURING
THE LATE WEDNESDAY-THURSDAY PERIOD. ADJUSTMENTS WILL UNDOUBTEDLY BE
REQUIRED AS SUITE OF MODELS DEVELOP BETTER CONVERGENCE/AGREEMENT IN
THEIR SOLUTIONS.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740...10 PM SUNDAY TO 3 AM TUESDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1149 AM CST Sun Dec 21 2014
.UPDATE...
ISSUED AT 1035 AM CST SUN DEC 21 2014
16z/10am visible satellite imagery shows cloud cover blanketing
much of central Illinois: however, skies remain mostly clear along
and south of the I-70 corridor into the Ohio River Valley.
Short-wave ridging in advance of an upper-level disturbance over
the Central Plains will allow heights to slowly rise today.
This along with continued backed southeasterly low-level flow will
cause the leading edge of the cloud cover to erode
north/northwestward this afternoon. Am already beginning to see
evidence of this on satellite this morning, so have updated sky
grids accordingly. End result will be mostly sunny skies
along/south of I-70, with skies becoming partly sunny as far
northwest as a Shelbyville to Champaign line. Further west, mostly
cloudy conditions will prevail across the remainder of the area.
High temperatures will be a few degrees warmer than yesterday,
with readings reaching the upper 30s and lower 40s.
&&
.SHORT TERM...(Today)
ISSUED AT 537 AM CST SUN DEC 21 2014
All but extreme southeast Illinois was cloudy early this morning and
the latest satellite trends suggest the southeast may see the clouds
move in for a brief time over the next couple of hours. With the
clear sky, a few locations in southeast Illinois have seen some
patchy fog develop, but with the clouds starting to move in we don`t
expect the fog to become widespread. Further to the northwest, some
patchy drizzle has been occurring over parts of extreme eastern Iowa
and some of that, at least based on radar, was tracking into areas
mainly along and west of the Illinois River, so will carry some
patchy drizzle wording for early this morning before that shifts to
our north. Surface temperatures have risen into the middle 30s early
this morning along with dew points now into the lower 30s, so am not
expecting any problems from freezing drizzle at this point.
The slow moving high pressure system that had given parts of our
area some sunshine the past couple of days was finally drifting off
to our east allowing a southerly flow to develop over most of the
forecast area. Forecast soundings indicate our southeast counties
may see the lower cloud cover drift north-northeast out of their
area this morning allowing some sun for a time today. Further north
and west, short range models not as optimistic with a mostly cloudy
sky prevailing. We should see the temperatures continue to moderate
from the highs of yesterday with most areas close to or above the 40
degree mark this afternoon.
&&
.LONG TERM...(Tonight through Saturday)
ISSUED AT 537 AM CST SUN DEC 21 2014
Still looking like only one major system to impact central and
southeast Illinois through the coming week. Unfortunately, the
potential exists for the biggest travel headaches with this system
to arrive later Tuesday night into Christmas Eve. However, it should
be noted that no model consensus exists with respect to this
system`s snow potential locally. In fact, at this point, more model
solutions keep the snowfall minimal than not. Nevertheless, it would
be prudent to keep an eye on the forecast heading into the Christmas
holiday as the ultimate outcome becomes more clear.
High pressure at the surface and mostly neutral upper flow aloft
will keep its grip on the local weather for one more day on Sunday.
Southerly return flow on the back side of the surface ridge will
push temperatures a few degrees warmer than today. Meanwhile, a
vigorous upper wave, currently crashing ashore along the Pacific
Northwest coast, will begin to dig a significant trof over the
Plains, also inducing surface cyclogenesis.
Strong WAA/isentropic ascent ahead of this slow moving system will
begin to spread rain into the area on Monday. The rain chances will
continue into Monday night and Tuesday. This initial part of the
forecast is fairly well agreed upon by the models.
The initial surface low beneath the mean Plains upper trof will not
move much across the northern Plains into the upper Midwest between
Monday and Tuesday. Attention then turns to another vigorous wave
that will round the base of the mean trof Tuesday into Wednesday.
This wave should induce a second surface low, one that will become
dominant, as it lifts northeast into Canada by the end of the week.
The model agreement with the timing/track/strength of this secondary
low by Tuesday night into Wednesday is not very good. The track of
this low is critical to how quickly our precipitation will change
over to snow Tuesday night into Wednesday, and if we will be
impacted by the heavier snowfall within this system`s deformation
zone. While the threat is certainly there, at this point only the
GFS has been impacting the forecast area very significantly.
Behind the midweek system, another wave will arrive by Friday.
However, the models have been trending weaker with this system
overall, as well as drier. So, have backed away from rain and/or
snow chances as this system arrives.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1149 AM CST SUN DEC 21 2014
MVFR ceilings prevail at the KILX terminals late this morning:
however, the cloud cover is beginning to erode across east-central
Illinois. 1730z visible satellite imagery shows clearing line from
KPRG to just north of K1H2 and lifting slowly northward. Based on
timing tools and latest HRRR forecast, skies will partially clear
at KCMI between 20z and 21z. Further west, forecast soundings
suggest a continued MVFR overcast through the afternoon before
ceilings gradually improve to VFR this evening in advance of an
approaching storm system. IFR ceilings will develop/spread across
the area between 13z and 16z Mon as rain showers arrive from the
southwest. Winds will be from the S/SE at 10-5kt through the
entire period.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barnes
SHORT TERM...Smith
LONG TERM...07
AVIATION...Barnes
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1152 PM CST SAT DEC 20 2014
.UPDATE...
904 PM CST
WE STILL HAVE THE POSSIBILITY OF PATCHY FREEZING DRIZZLE
OVERNIGHT WITH THE BEST CHANCE IN OUR WESTERN AREAS. THAT
SAID...TEMPERATURES ARE AROUND FREEZING AND NOT EXPECTED TO DROP
MUCH GIVEN THE CLOUD COVER AND WARM ADVECTION PATTERN SETTING UP.
AT THIS POINT IMPACTS DO LOOK MINIMAL...ESPECIALLY FARTHER EAST. HAVE
KEPT TEMPS NEARLY STEADY OVERNIGHT. SOME PRECIPITATION MAY MAKE IT
CLOSER TO CHICAGO LATE TONIGHT INTO SUNDAY MORNING ONCE THE WARM
FRONT GETS CLOSER...BUT IT WOULD BE LARGELY IN THE FORM OF PATCHY
DRIZZLE. FOG MAY BE POSSIBLE AS WELL OVERNIGHT.
KMD
&&
.SHORT TERM...
247 PM CST
THROUGH SUNDAY NIGHT...
THE STREAK OF CLOUDY DAYS CONTINUES...WITH THE STUBBORN PATTERN TO
CONTINUE. AS A RESULT OF THE THICK CLOUD COVER...AND LACK OF
ORGANIZED ADVECTION OF ANY WARMER AIR AT THE SFC...TEMPS HAVE HELD
MAINLY ARND 30 TO 35 ACROSS THE BULK OF THE CWFA. SFC RIDGE
CONTINUES TO DRIFT EAST THIS AFTN...WITH A WEAK SOUTHERLY FLOW
DEVELOPING. THERE WAS A WEAK MID-LVL VORT LIFTING NORTHEAST ACROSS
SOUTHERN WISC/WESTERN LOWER MI...WHICH WAS ABLE TO PRODUCE A FEW
FLURRIES ACROSS THE FAR NORTHERN IL AREAS.
THIS AFTN/EARLY EVE LOOKS TO REMAIN QUIET/DRY...WITH A LIGHT
SOUTH/SOUTHEAST WIND. IR IMAGERY SHOWS THE NEXT WAVE ACROSS THE
CENTRAL PLAINS...WHICH IS PROGGED TO ARRIVE ACROSS NORTHWEST IL
AFTER MIDNIGHT. THERE APPEARS TO BE SOME WEAK ADVECTION OF MOISTURE
IN THE LOW-LEVELS OVERNIGHT. SOUNDINGS SUGGEST A NARROW WARM WEDGE
ALOFT WHICH COULD TRANSITION ANY PRECIP OVERNIGHT TO LIQUID. THE
FORCING/OMEGA IS RATHER WEAK...WHICH MAY LIMIT DROPLET SIZE AND
RESULT IN JUST PATCHY FREEZING DRIZZLE. TEMPS WILL LIKELY NOT MOVE
MUCH OVERNIGHT...SO HAVE HELD ONTO MID/UPR 20S OVERNIGHT.
LOCAL ARW8KM SOLUTION INDICATES THE MOISTURE TO BE RATHER MARGINAL
WITH THE SYSTEM ARRIVING OVERNIGHT/SUN MORNING...BUT PROGRESSIVE AND
LIFTING NORTH OF THE CWFA BY MIDDAY. WEAK THERMAL RIDGE AT 850MB
WOULD SUGGEST TEMPS MAY ACTUALLY WARM SUN AFTN...HOWEVER GIVEN THE
STUBBORN PATTERN WE HAVE BEEN IN WOULD LEAN TOWARDS NUDGING TEMPS
DOWN A DEGREE OR TWO. MOISTURE LAYER WILL REMAIN LOCKED IN ACROSS
THE REGION THRU SUN/SUN NGT. WITH A CONTINUED SOUTHERLY FLOW AT THE
SFC...TEMPS WILL LIKELY ONLY FALL TO ARND 30/LOW 30S.
BEACHLER
&&
.LONG TERM...
247 PM CST
MONDAY THROUGH SATURDAY...
500MB TROUGH BEGINS TO DIG INTO THE CENTRAL CONUS MON MORNING...WITH
WARM AIR STEADILY ADVECTING NORTH ACROSS THE FORECAST AREA. WHILE
THE THICK CLOUD COVER WILL PERSIST...THE PUSH OF WARM/MOIST AIR WILL
BRING TEMPS INTO THE 40S THE FAR SOUTHERN CWFA COULD SEE A FEW
LOCATIONS TOUCH THE UPR 40S MON AFTN. PRECIP WILL STEADILY PUSH EAST
AS THE UPPER LEVEL SYSTEM PROGRESSES TOWARDS THE REGION...BUT WITH
THE WARM AIR IN PLACE PRECIP SHUD FALL AS RAIN.
MON NGT THE 500MB VORT WILL SLIDE INTO THE UPPER MIDWEST...BUT THE
TROUGH WILL DIG SOUTH ACROSS THE SOUTHERN PLAINS. GUIDANCE HAS BEEN
INDICATING A SECONDARY SHORTWAVE EJECTING FROM THE TROUGH AXIS...AND
LIFTING IT NORTHEAST ACROSS THE TENN VALLEY CHRISTMAS EVE. THE
NORTHERN SFC LOW WILL BE WRAPPED UP ACROSS CENTRAL WISC TUE...WITH
THE MOIST CHANNEL FEEDING NORTH ACROSS THE FORECAST AREA THRU TUE
AFTN. THE SOUTHERN LOW WILL BE QUICKLY DEEPENING AS IT LIFTS NORTH
ACROSS THE OHIO VALLEY WED MORNING...ALLOWING WINDS TO BE ON THE
INCREASE AND HELPING TO STEADILY TRANSITION PRECIP OVER FROM RAIN TO
SNOW POST FROPA WED MORNING.
THE LAST SEVERAL CYCLES OF GUIDANCE HAVE DEMONSTRATED DIFFERENCES IN
PLACEMENT/TRACK OF THE SFC LOW WED AFTN/EVE. LATEST SOLUTION IS
PROGGED TO LIFT NORTH ACROSS NORTHERN IN AND THEN SLIGHTLY
RETROGRADE ACROSS THE SOUTHERN TIP OF LAKE MICHIGAN WED EVE. THEN BY
CHRISTMAS DAY THE TROUGH WILL BE PIVOTING EAST AND HELPING TO LIFT
THE SFC LOW NORTHEAST AWAY FROM THE REGION. SOME WRAP AROUND
MOISTURE/SNOW LOOKS FAVORABLE WED NGT/THUR MORNING...BEFORE COMING
TO AN END JUST AFTER DAYBREAK CHRISTMAS MORNING. THIS SYSTEM WILL
CONTINUE TO BE CLOSELY MONITORED.
TEMPS WILL BE RETURNING TO MORE SEASONAL CONDS...WITH HIGHS
CHRISTMAS DAY IN THE LOW/MID 30S. FLOW REMAINS RATHER PROGRESSIVE
WITH ANOTHER WEAK PUSH OF WARMER AIR RETURNING FRI AND TEMPS BACK TO
THE UPR 30S/LOW 40S. THEN FOR FRI ENSEMBLES ARE INDICATING YET
ANOTHER TROUGH BEGINNING TO DIG INTO THE CENTRAL CONUS...WITH A SFC
LOW LIFTING NORTHEAST ACROSS THE WESTERN GREAT LAKES.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CEILINGS DEVELOPING PRE-DAWN AND LIKELY LINGERING THROUGH
THE PERIOD.
* POTENTIAL FOR A PERIOD OF FOG/LIGHT FREEZING DRIZZLE THIS
MORNING...THOUGH BETTER POTENTIAL WEST/NORTHWEST OF CHICAGO
TERMINALS.
RATZER
//DISCUSSION...UPDATED 06Z...
LIGHT SOUTHWEST FLOW JUST ABOVE THE SURFACE IS ADVECTING LOW LEVEL
MOISTURE STEADILY NORTHEASTWARD ACROSS THE REGION...WITH EXPANSIVE
AREA OF MVFR/IFR/LIFR EXTENDING UPSTREAM TO THE WEST AND SOUTHWEST
OF NORTHERN ILLINOIS TERMINALS. MAIN MOIST AXIS AND LOWEST
CONDITIONS ALONG WITH FOG AND DRIZZLE/FREEZING DRIZZLE/FLURRIES
LIFTING FROM IOWA INTO NORTHWEST ILLINOIS...SETTING UP LIKELY IFR
CONDITIONS EARLY THIS MORNING FOR KRFD. FARTHER EAST...CHICAGO
AREA TERMINALS EXPECTED TO DETERIORATE TO MVFR BUT LOWER
CONDITIONS SHOULD REMAIN JUST OFF TO THE WEST/NORTHWEST. GIVEN
EXTENSIVE UPSTREAM CONDITIONS WOULD EXPECT LOW CLOUDS TO LINGER
THROUGH MUCH OF THE PERIOD AS SURFACE LOW PRESSURE DEVELOPING OVER
THE NORTHERN PLAINS MAINTAINS SOUTHWEST FLOW ALOFT.
SOUTH WINDS AROUND 5 KT WILL LIKELY BECOME A LITTLE EAST OF SOUTH
IN 170-160 DEGREE RANGE THROUGH THE DAY WITH SPEEDS INCREASING
INTO THE 10-15 KT RANGE. MODEL SOUNDINGS SUGGEST SOME GUSTS ABOVE
15 KT POSSIBLE LATER THIS AFTERNOON/TONIGHT...THOUGH SHALLOW MIXED
LAYER ARGUES AGAINST PREVAILING GUST MENTION.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN CEILING TRENDS THIS MORNING.
* LOW CONFIDENCE IN CEILING TRENDS THIS AFTERNOON/TONIGHT.
* LOW CONFIDENCE IN MVFR FOG AND DZ/FZDZ POTENTIAL THIS MORNING.
* MEDIUM-HIGH CONFIDENCE IN WINDS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...MVFR/IFR EARLY LOWERING TO IFR/LIFR. RAIN DEVELOPING
LATE.
TUESDAY...ONCL SHRA. IFR PROBABLE.
WEDNESDAY...CHANCE SHRA/SHSN. MVFR LIKELY. IFR POSSIBLE.
THURSDAY...MVFR CIGS POSSIBLE EARLY.
FRIDAY...CHANCE OF RA/SN LATE. MVFR CIGS POSSIBLE AGAIN.
IZZI
&&
.MARINE...
203 PM CST
LIGHT SOUTHEAST TO EAST WINDS WILL INCREASE TO 10-25 KT TOMORROW
MORNING THEN TO 30 KT IN THE AFTERNOON AS THE GRADIENT TIGHTENS
BETWEEN THE DEPARTING HIGH AND THE NEXT LOW. THE LOW MOVES OVER THE
DAKOTAS SUNDAY NIGHT AND MODELS AGREE A BIT MORE IN THE PATTERN
EARLY NEXT WEEK. HAVE MEDIUM CONFIDENCE IN THE WIND FORECAST WITH
THIS NEXT LOW. THE LOW WEAKENS AS IT MOVES OVER WISCONSIN TUESDAY
AND A SECOND LOW FORMS OVER THE SOUTHERN MISSISSIPPI VALLEY TUESDAY
AFTERNOON. THE SECOND LOW WILL RACE NORTH AND DEEPEN REACHING
MICHIGAN WEDNESDAY. MODELS DIFFER ON HOW QUICKLY THE LOW WILL REACH
MICHIGAN. BOTH MODELS CONTINUE TO FEATURE WESTERLY HIGH END GALES
BEHIND THE LOW WEDNESDAY AFTERNOON INTO THURSDAY. WEST WINDS
DIMINISH THURSDAY AS THE LOW CONTINUES OFF TO THE NORTH. THE NEXT
LOW MOVES OVER THE SOUTHERN PLAINS THURSDAY AFTERNOON. GUIDANCE
DIFFERS ON THIS LOWS PATH BUT IT SHOULD IMPACT THE LAKE LATE NEXT
WEEK.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740...10 PM SUNDAY 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 Sat Dec 20 2014
.UPDATE...
ISSUED AT 857 PM CST SAT DEC 20 2014
Clouds cover most of the CWA tonight, but a small area in the east
and southeast is clear at the moment. Expect this area to cloud
over overnight. However, need to make some adjustments to the
cloud cover grids tonight. Remainder of grids look ok. Will send
an update on the forecast, but will not be a change for most of
the area. Changes will be in the east and southeast only.
&&
.SHORT TERM...(Tonight)
ISSUED AT 259 PM CST SAT DEC 20 2014
Cloudy skies persist across much of central Illinois this afternoon:
however, 20z/2pm visible satellite imagery shows a large tear in the
overcast developing from near Decatur southeastward to Flora.
Although the HRRR has been a bit overdone with the clearing, it
continues to suggest at least thinning clouds across the E/SE KILX
CWA late this afternoon into the evening. In fact, with 925mb winds
remaining light/variable and not really picking up a strong S/SW
component until Sunday, portions of the SE may see partly cloudy
conditions persist through the night. Further north and west, low
clouds will be on the increase from the west. Forecast soundings
and model RH profiles indicate that the lowest clouds/fog will
remain just W/NW of central Illinois tonight. Due to cloud cover
and a light S/SE wind, low temperatures will be a couple of degrees
warmer than last night. Coolest readings in the middle 20s will
occur south of I-70 where skies will likely remain partly cloudy,
while lows stay in the upper 20s/lower 30s elsewhere.
&&
.LONG TERM...(Sunday through Saturday)
ISSUED AT 259 PM CST SAT DEC 20 2014
Still looking like only one major system to impact central and
southeast Illinois through the coming week. Unfortunately, the
potential exists for the biggest travel headaches with this system
to arrive later Tuesday night into Christmas Eve. However, it should
be noted that no model consensus exists with respect to this
system`s snow potential locally. In fact, at this point, more model
solutions keep the snowfall minimal than not. Nevertheless, it would
be prudent to keep an eye on the forecast heading into the Christmas
holiday as the ultimate outcome becomes more clear.
High pressure at the surface and mostly neutral upper flow aloft
will keep its grip on the local weather for one more day on Sunday.
Southerly return flow on the back side of the surface ridge will
push temperatures a few degrees warmer than today. Meanwhile, a
vigorous upper wave, currently crashing ashore along the Pacific
Northwest coast, will begin to dig a significant trof over the
Plains, also inducing surface cyclogenesis.
Strong WAA/isentropic ascent ahead of this slow moving system will
begin to spread rain into the area on Monday. The rain chances will
continue into Monday night and Tuesday. This initial part of the
forecast is fairly well agreed upon by the models.
The initial surface low beneath the mean Plains upper trof will not
move much across the northern Plains into the upper Midwest between
Monday and Tuesday. Attention then turns to another vigorous wave
that will round the base of the mean trof Tuesday into Wednesday.
This wave should induce a second surface low, one that will become
dominant, as it lifts northeast into Canada by the end of the week.
The model agreement with the timing/track/strength of this secondary
low by Tuesday night into Wednesday is not very good. The track of
this low is critical to how quickly our precipitation will change
over to snow Tuesday night into Wednesday, and if we will be
impacted by the heavier snowfall within this system`s deformation
zone. While the threat is certainly there, at this point only the
GFS has been impacting the forecast area very significantly.
Behind the midweek system, another wave will arrive by Friday.
However, the models have been trending weaker with this system
overall, as well as drier. So, have backed away from rain and/or
snow chances as this system arrives.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
ISSUED AT 1137 PM CST SAT DEC 20 2014
Cloudy skies will continue at all sites next 24hrs. Cigs are
hovering around 3kft with PIA and SPI above 3kft and BMI, DEC, and
CMI below. So will just have 3kft cigs at all sites since PIA and
SPI will likely drop below 3kft sometime overnight. Based on model
soundings and RH fields, am thinking the MVFR cigs will continue
through tomorrow and tomorrow night. Winds will be south-southeast
through the period, with speeds increase to around 10kts tomorrow
afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Auten
SHORT TERM...Barnes
LONG TERM...Bak
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1027 AM EST SUN DEC 21 2014
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 301 AM EST SUN DEC 21 2014
A LOW PRESSURE SYSTEM WILL BRING PRECIPITATION TO CENTRAL INDIANA
MONDAY THROUGH WEDNESDAY. AFTER A DRY CHRISTMAS...CHANCES FOR
PRECIPITATION WILL RETURN FRIDAY WITH A WEAKER SYSTEM. WARM AIR
AHEAD OF THE FIRST SYSTEM COULD BRING THE WARMEST READINGS OF
DECEMBER ON TUESDAY...THEN TEMPERATURES WILL RETURN TO CLOSER TO
AVERAGE BY CHRISTMAS.
&&
.NEAR TERM.../REST OF TODAY/...
ISSUED AT 1027 AM EST SUN DEC 21 2014
PATCHES OF LOW CLOUDS LINGER ACROSS THE LOCAL AREA LATE THIS
MORNING...ESPECIALLY OVER THE NORTHWESTERN/NORTHERN ZONES. THESE
CLOUDS HAVE BEEN HOLDING STEADY OR SLOWLY RETREATING OVER THE PAST
COUPLE OF HOURS. SHORT TERM MODELS SUGGEST THE AIR MASS NEAR THE
CLOUD LEVEL WILL BE SLOWLY DRYING OUT TODAY...SO DON/T THINK THE LOW
CLOUDS WILL EXPAND ALL THAT MUCH TODAY.
CURRENT FORECAST HIGHS STILL LOOK GOOD. NO UPDATES PLANNED AT THIS
TIME.
PREVIOUS DISCUSSION FOLLOWS.
SKIES HAVE CLEARED ACROSS A GOOD PORTION OF CENTRAL INDIANA EARLY
THIS MORNING...BUT ADDITIONAL LOW CLOUDS WERE NEAR THE
ILLINOIS/INDIANA BORDER AND MOVING SLOWLY EAST.
CLOUD COVER WILL BE TOUGH TO PIN DOWN TODAY AND ONCE AGAIN
CONFIDENCE IS LOW IN THE DETAILS. LOW CLOUDS WILL MARCH INTO WESTERN
AND NORTHWESTERN SECTIONS OF THE AREA THIS MORNING. HOWEVER DRIER
AIR WILL FLOW INTO THE AREA AS WINDS INCREASE OUT OF THE SOUTHEAST.
FOR NOW WILL GO MOSTLY CLOUDY ACROSS THE NORTHWEST FORECAST
AREA...WITH SKIES REMAINING/BECOMING PARTLY CLOUDY ELSEWHERE.
ADJUSTMENTS WILL LIKELY HAVE TO BE MADE LATER THIS MORNING AS THE
EVOLUTION OF THE CLOUDS BECOMES CLEARER.
TEMPERATURES HAVE COOLED MORE THAN EXPECTED EARLY THIS MORNING DUE
TO THE PARTIAL CLEARING. THIS COLD START WILL HELP KEEP TEMPERATURES
BELOW MAV MOS AND CLOSER TO THE MET MOS TODAY.
&&
.SHORT TERM.../TONIGHT THROUGH TUESDAY NIGHT/
ISSUED AT 301 AM EST SUN DEC 21 2014
FOCUS IS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE
SHOWING DIFFERENCES AS WOULD BE EXPECTED WITH THE INCOMING SYSTEM
NOT FULLY SAMPLED YET. CANADIAN LOOKS TOO STRONG WITH THE
SYSTEM...WHILE THE LARGER CHANGE IN SOLUTIONS BETWEEN THE 12Z/00Z
ECMWF LEADS TO LOWER CONFIDENCE IN ITS SOLUTION THIS RUN. WILL USE A
BLEND OF REMAINING MODELS.
CLOUDS WILL INCREASE TONIGHT AS THE SYSTEM APPROACHES FROM THE WEST.
WILL GO A LITTLE WARMER THAN MAV MOS MOST AREAS.
ON MONDAY ISENTROPIC LIFT INCREASES DURING THE AFTERNOON. HOWEVER
DEEPER MOISTURE WILL BE SLOWER TO RETURN THANKS IN PART TO SOUTHEAST
WINDS IN THE LOWER LEVELS. WILL KEEP THE MORNING DRY AND GO WITH
SLIGHT CHANCE TO CHANCE POPS IN THE AFTERNOON. WITH THE CLOUDS AND
SOUTHEAST FLOW...MOS LOOKS TOO WARM FOR HIGHS. WILL CUT SOME.
MONDAY NIGHT AND TUESDAY FORCING RAMPS UP WITH SURFACE FRONT MOVING
INTO THE AREA...850MB WINDS APPROACHING 50KT...AND AN UPPER JET
MOVING IN. THUS WENT LIKELY POPS MOST AREAS BY LATE MONDAY NIGHT AND
LIKELY TO CATEGORICAL POPS ON TUESDAY.
CONTINUED LIKELY TO CATEGORICAL POPS TUESDAY NIGHT AS A SURFACE LOW
RIDES ALONG THE FRONT TOWARD CENTRAL INDIANA. LOOKS LIKE COLDER AIR
WILL BE SLOWER TO ARRIVE THAN PREVIOUSLY THOUGHT...SO WENT ALL RAIN
THROUGH TUESDAY NIGHT.
THE SYSTEM LOOKS TO BRING ENOUGH WARM UP INTO THE AREA ON TUESDAY
FOR HIGHS IN THE LOWER TO MIDDLE 50S...WHICH WILL BE THE WARMEST AIR
THIS MONTH ACROSS THE AREA.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
ISSUED AT 328 AM EST SUN DEC 21 2014
FOCUS FOR THE EXTENDED REMAINS ON POTENTIAL IMPACTS FROM A
STRENGTHENING LOW PRESSURE FOR CHRISTMAS EVE...FOLLOWED BY ANOTHER
STORM SYSTEM BRINGING PRECIPITATION TO THE OHIO VALLEY FRIDAY AND
FRIDAY NIGHT.
LEAD PORTION OF THE POWERFUL UPPER JET APPROACHING THE PACIFIC
NORTHWEST IS STARTING TO BE SAMPLED BY THE RAOB NETWORK.
HOWEVER...THAT HAS DONE LITTLE TO AID IN DEVELOPING A STRONGER
CONSENSUS FOR THE PHASED LOW PRESSURE SYSTEM TO IMPACT THE REGION
WEDNESDAY AS 00Z MODEL SUITE FRANKLY INTRODUCING MORE QUESTIONS THAN
ANSWERS. THE ECMWF AND OP GFS ARE BOTH SLOWER WITH PHASING THE
POLAR AND SUBTROPICAL JETS ALOFT...WITH THE STRENGTHENING UPPER
TROUGH NOT TAKING ON A NEGATIVE TILT UNTIL LATER ON WEDNESDAY AS THE
FEATURE PASSES CENTRAL INDIANA. CONSEQUENTLY THE DEEPENING SURFACE
LOW IS ALSO SLOWER TO TAKE PLACE...OCCURRING OVER THE EASTERN GREAT
LAKES BY EARLY CHRISTMAS MORNING. GFS ENSEMBLE MEMBERS STILL HAVE
QUITE A BIT OF SPREAD AND IT SHOULD BE NOTED THAT A COUPLE MEMBERS
REMAIN DEEPER AND FURTHER WEST WITH THE SURFACE WAVE TRACK.
TAKING INTO CONSIDERATION THAT MODEL SPREAD REMAINS LARGER THAN
DESIRED AND WITH BOTH THE OP GFS AND ECMWF SHIFTING THE LOW TRACK
FURTHER EAST WITH A SLOWER ENERGY PHASE...IT REMAINS PREMATURE TO
LATCH ONTO A SPECIFIC SOLUTION. 12Z RUNS TODAY AND DEFINITELY THE
00Z RUNS TONIGHT SHOULD GET FULL SAMPLING OF THE STRONG UPPER JET
ENERGY COMING INTO THE PACIFIC NORTHWEST. WITH THIS FEATURE SET TO
BE A MAJOR PLAYER INT HE EVOLUTION OF THE STORM SYSTEM...MAY
FINALLY START TO SEE A SLOW INCREASE IN MODEL CONSENSUS.
DO PLAN TO SLOW THE ARRIVAL OF THE COLDER AIR ON WEDNESDAY WITH RAIN
GRADUALLY CHANGING TO SNOW ON WEDNESDAY AFTERNOON AND EVENING.
CANNOT RULE OUT LIGHT ACCUMS BUT ATTEMPT TO EMPLOY ANY MORE DETAIL
WOULD BE FUTILE WITH SUCH TRACK UNCERTAINTY TO THE SURFACE WAVE. IF
THE WAVE TRACKS CLOSER TO THE FORECAST AREA VERSUS FURTHER
EAST...POTENTIAL FOR LIGHT ACCUMS WOULD BE GREATER WITH THE MID
LEVEL DEFORMATION BAND ALIGNING IN SOME MANNER OVER THE FORECAST
AREA. AS IT STANDS...WILL MAINTAIN CHANCE POPS THROUGH WEDNESDAY
NIGHT WITH STRONG WIND GUSTS BEING THE PRIMARY IMPACT...AND
POTENTIAL LIGHT ACCUMS AS A SECONDARY IMPACT. THE THREAT FOR TRAVEL
DISRUPTIONS REMAINS GREATEST DURING THIS TIME PERIOD...AND THOSE
WITH TRAVEL PLANS ARE ENCOURAGED TO MONITOR FORECASTS OVER THE NEXT
FEW DAYS.
CHRISTMAS DAY LOOKS TO BE QUIET AS THE SURFACE WAVE QUICKLY LIFTS
AWAY FROM THE REGION WITH SURFACE RIDGING DEVELOPING OVER THE OHIO
VALLEY. HIGHLY AMPLIFIED FLOW ALOFT WILL MAINTAIN AN ACTIVE
PATTERN...WITH ANOTHER SURFACE LOW TRACKING OUT OF THE CENTRAL
PLAINS AND INTO THE GREAT LAKES ON FRIDAY. STILL A LOT OF MODEL
VARIANCE WITH THIS SYSTEM...AND THAT IS NOT LIKELY TO CHANGE UNTIL
MODELS CAN GAIN A BETTER CONSENSUS ON THE CHRISTMAS EVE STORM. WILL
CARRY CHANCE POPS FOR FRIDAY AND FRIDAY NIGHT...WITH RAIN ON FRIDAY
TRANSITIONING TO LIGHT SNOW FRIDAY NIGHT BEFORE ENDING. SURFACE HIGH
PRESSURE WILL RETURN FOR THE WEEKEND...WITH CHILLY AND MAINLY DRY
CONDITIONS AS A SHARP UPPER TROUGH ESTABLISHES OVER THE GREAT
LAKES.
&&
.AVIATION /DISCUSSION FOR 211500Z IND TAF UPDATE/...
ISSUED AT 920 AM EST SUN DEC 21 2014
ONLY INSIGNIFICANT MINOR CHANGE TO VFR CONDITIONS.
PREVIOUS DISCUSSION FOLLOWS...
MVFR CONDITIONS POSSIBLE AT TIMES THIS MORNING...OTHERWISE VFR
CONDITIONS EXPECTED.
MUCH OF THE FORECAST AREA REMAINS UNDER MOSTLY CLEAR SKIES WITH A
LIGHT HAZE FROM LINGERING MOISTURE LEFT UNDER THE REMNANT
INVERSION PRODUCING VISIBILITIES IN THE 4-6SM RANGE. STRATUS
REMAINS ACROSS FAR NORTHERN COUNTIES BACK INTO ILLINOIS...BUT HAS
LARGELY SHOWN AN INABILITY TO EXPAND BACK INTO THE REGION OVER THE
LAST SEVERAL HOURS. RAP INDICATING S/SE FLOW IN THE 925-850MB
LAYER WHICH IS LIKELY KEEPING THE THICKER CLOUDS FROM RETURNING TO
THE REGION. MODEL SOUNDINGS AND RH PROGS INDICATE THAT THIS IS
LIKELY TO CONTINUE FOR MOST OF THE DAY WITH INCREASINGLY DRIER AIR
SLIPPING INTO THE BOUNDARY LAYER. GROWING OPTIMISM THAT THE REGION
WILL ENJOY THE MOST SUNSHINE SEEN IN MORE THAN A WEEK. ENOUGH LOW
LEVEL MOISTURE PRESENT THAT COULD SEE SCATTERED STRATOCU DEVELOP
THIS AFTERNOON. SOUTHEAST WINDS WILL BE 5-10KTS TODAY.
MAINLY CLEAR SKIES WILL CONTINUE THIS EVENING WITH A SLOW
INCREASE IN MID LEVEL CLOUDS AS A WARM FRONT APPROACHES FROM THE
WEST. LOW LEVEL RH PROGS SHOW THE LOWER STRATUS DECK IS LIKELY TO
MAKE A RETURN TOWARDS DAYBREAK MONDAY AS WELL WITH INCREASING
MOISTURE ADVECTING INTO THE OHIO VALLEY. LIGHT SOUTHEAST WINDS
WILL CONTINUE OVERNIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50/JAS
SHORT TERM...50
LONG TERM....RYAN
AVIATION...RYAN/MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
920 AM EST SUN DEC 21 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 301 AM EST SUN DEC 21 2014
A LOW PRESSURE SYSTEM WILL BRING PRECIPITATION TO CENTRAL INDIANA
MONDAY THROUGH WEDNESDAY. AFTER A DRY CHRISTMAS...CHANCES FOR
PRECIPITATION WILL RETURN FRIDAY WITH A WEAKER SYSTEM. WARM AIR
AHEAD OF THE FIRST SYSTEM COULD BRING THE WARMEST READINGS OF
DECEMBER ON TUESDAY...THEN TEMPERATURES WILL RETURN TO CLOSER TO
AVERAGE BY CHRISTMAS.
&&
.NEAR TERM.../TODAY/
ISSUED AT 301 AM EST SUN DEC 21 2014
SKIES HAVE CLEARED ACROSS A GOOD PORTION OF CENTRAL INDIANA EARLY
THIS MORNING...BUT ADDITIONAL LOW CLOUDS WERE NEAR THE
ILLINOIS/INDIANA BORDER AND MOVING SLOWLY EAST.
CLOUD COVER WILL BE TOUGH TO PIN DOWN TODAY AND ONCE AGAIN
CONFIDENCE IS LOW IN THE DETAILS. LOW CLOUDS WILL MARCH INTO WESTERN
AND NORTHWESTERN SECTIONS OF THE AREA THIS MORNING. HOWEVER DRIER
AIR WILL FLOW INTO THE AREA AS WINDS INCREASE OUT OF THE SOUTHEAST.
FOR NOW WILL GO MOSTLY CLOUDY ACROSS THE NORTHWEST FORECAST
AREA...WITH SKIES REMAINING/BECOMING PARTLY CLOUDY ELSEWHERE.
ADJUSTMENTS WILL LIKELY HAVE TO BE MADE LATER THIS MORNING AS THE
EVOLUTION OF THE CLOUDS BECOMES CLEARER.
TEMPERATURES HAVE COOLED MORE THAN EXPECTED EARLY THIS MORNING DUE
TO THE PARTIAL CLEARING. THIS COLD START WILL HELP KEEP TEMPERATURES
BELOW MAV MOS AND CLOSER TO THE MET MOS TODAY.
&&
.SHORT TERM.../TONIGHT THROUGH TUESDAY NIGHT/
ISSUED AT 301 AM EST SUN DEC 21 2014
FOCUS IS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE
SHOWING DIFFERENCES AS WOULD BE EXPECTED WITH THE INCOMING SYSTEM
NOT FULLY SAMPLED YET. CANADIAN LOOKS TOO STRONG WITH THE
SYSTEM...WHILE THE LARGER CHANGE IN SOLUTIONS BETWEEN THE 12Z/00Z
ECMWF LEADS TO LOWER CONFIDENCE IN ITS SOLUTION THIS RUN. WILL USE A
BLEND OF REMAINING MODELS.
CLOUDS WILL INCREASE TONIGHT AS THE SYSTEM APPROACHES FROM THE WEST.
WILL GO A LITTLE WARMER THAN MAV MOS MOST AREAS.
ON MONDAY ISENTROPIC LIFT INCREASES DURING THE AFTERNOON. HOWEVER
DEEPER MOISTURE WILL BE SLOWER TO RETURN THANKS IN PART TO SOUTHEAST
WINDS IN THE LOWER LEVELS. WILL KEEP THE MORNING DRY AND GO WITH
SLIGHT CHANCE TO CHANCE POPS IN THE AFTERNOON. WITH THE CLOUDS AND
SOUTHEAST FLOW...MOS LOOKS TOO WARM FOR HIGHS. WILL CUT SOME.
MONDAY NIGHT AND TUESDAY FORCING RAMPS UP WITH SURFACE FRONT MOVING
INTO THE AREA...850MB WINDS APPROACHING 50KT...AND AN UPPER JET
MOVING IN. THUS WENT LIKELY POPS MOST AREAS BY LATE MONDAY NIGHT AND
LIKELY TO CATEGORICAL POPS ON TUESDAY.
CONTINUED LIKELY TO CATEGORICAL POPS TUESDAY NIGHT AS A SURFACE LOW
RIDES ALONG THE FRONT TOWARD CENTRAL INDIANA. LOOKS LIKE COLDER AIR
WILL BE SLOWER TO ARRIVE THAN PREVIOUSLY THOUGHT...SO WENT ALL RAIN
THROUGH TUESDAY NIGHT.
THE SYSTEM LOOKS TO BRING ENOUGH WARM UP INTO THE AREA ON TUESDAY
FOR HIGHS IN THE LOWER TO MIDDLE 50S...WHICH WILL BE THE WARMEST AIR
THIS MONTH ACROSS THE AREA.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
ISSUED AT 328 AM EST SUN DEC 21 2014
FOCUS FOR THE EXTENDED REMAINS ON POTENTIAL IMPACTS FROM A
STRENGTHENING LOW PRESSURE FOR CHRISTMAS EVE...FOLLOWED BY ANOTHER
STORM SYSTEM BRINGING PRECIPITATION TO THE OHIO VALLEY FRIDAY AND
FRIDAY NIGHT.
LEAD PORTION OF THE POWERFUL UPPER JET APPROACHING THE PACIFIC
NORTHWEST IS STARTING TO BE SAMPLED BY THE RAOB NETWORK.
HOWEVER...THAT HAS DONE LITTLE TO AID IN DEVELOPING A STRONGER
CONSENSUS FOR THE PHASED LOW PRESSURE SYSTEM TO IMPACT THE REGION
WEDNESDAY AS 00Z MODEL SUITE FRANKLY INTRODUCING MORE QUESTIONS THAN
ANSWERS. THE ECMWF AND OP GFS ARE BOTH SLOWER WITH PHASING THE
POLAR AND SUBTROPICAL JETS ALOFT...WITH THE STRENGTHENING UPPER
TROUGH NOT TAKING ON A NEGATIVE TILT UNTIL LATER ON WEDNESDAY AS THE
FEATURE PASSES CENTRAL INDIANA. CONSEQUENTLY THE DEEPENING SURFACE
LOW IS ALSO SLOWER TO TAKE PLACE...OCCURRING OVER THE EASTERN GREAT
LAKES BY EARLY CHRISTMAS MORNING. GFS ENSEMBLE MEMBERS STILL HAVE
QUITE A BIT OF SPREAD AND IT SHOULD BE NOTED THAT A COUPLE MEMBERS
REMAIN DEEPER AND FURTHER WEST WITH THE SURFACE WAVE TRACK.
TAKING INTO CONSIDERATION THAT MODEL SPREAD REMAINS LARGER THAN
DESIRED AND WITH BOTH THE OP GFS AND ECMWF SHIFTING THE LOW TRACK
FURTHER EAST WITH A SLOWER ENERGY PHASE...IT REMAINS PREMATURE TO
LATCH ONTO A SPECIFIC SOLUTION. 12Z RUNS TODAY AND DEFINITELY THE
00Z RUNS TONIGHT SHOULD GET FULL SAMPLING OF THE STRONG UPPER JET
ENERGY COMING INTO THE PACIFIC NORTHWEST. WITH THIS FEATURE SET TO
BE A MAJOR PLAYER INT HE EVOLUTION OF THE STORM SYSTEM...MAY
FINALLY START TO SEE A SLOW INCREASE IN MODEL CONSENSUS.
DO PLAN TO SLOW THE ARRIVAL OF THE COLDER AIR ON WEDNESDAY WITH RAIN
GRADUALLY CHANGING TO SNOW ON WEDNESDAY AFTERNOON AND EVENING.
CANNOT RULE OUT LIGHT ACCUMS BUT ATTEMPT TO EMPLOY ANY MORE DETAIL
WOULD BE FUTILE WITH SUCH TRACK UNCERTAINTY TO THE SURFACE WAVE. IF
THE WAVE TRACKS CLOSER TO THE FORECAST AREA VERSUS FURTHER
EAST...POTENTIAL FOR LIGHT ACCUMS WOULD BE GREATER WITH THE MID
LEVEL DEFORMATION BAND ALIGNING IN SOME MANNER OVER THE FORECAST
AREA. AS IT STANDS...WILL MAINTAIN CHANCE POPS THROUGH WEDNESDAY
NIGHT WITH STRONG WIND GUSTS BEING THE PRIMARY IMPACT...AND
POTENTIAL LIGHT ACCUMS AS A SECONDARY IMPACT. THE THREAT FOR TRAVEL
DISRUPTIONS REMAINS GREATEST DURING THIS TIME PERIOD...AND THOSE
WITH TRAVEL PLANS ARE ENCOURAGED TO MONITOR FORECASTS OVER THE NEXT
FEW DAYS.
CHRISTMAS DAY LOOKS TO BE QUIET AS THE SURFACE WAVE QUICKLY LIFTS
AWAY FROM THE REGION WITH SURFACE RIDGING DEVELOPING OVER THE OHIO
VALLEY. HIGHLY AMPLIFIED FLOW ALOFT WILL MAINTAIN AN ACTIVE
PATTERN...WITH ANOTHER SURFACE LOW TRACKING OUT OF THE CENTRAL
PLAINS AND INTO THE GREAT LAKES ON FRIDAY. STILL A LOT OF MODEL
VARIANCE WITH THIS SYSTEM...AND THAT IS NOT LIKELY TO CHANGE UNTIL
MODELS CAN GAIN A BETTER CONSENSUS ON THE CHRISTMAS EVE STORM. WILL
CARRY CHANCE POPS FOR FRIDAY AND FRIDAY NIGHT...WITH RAIN ON FRIDAY
TRANSITIONING TO LIGHT SNOW FRIDAY NIGHT BEFORE ENDING. SURFACE HIGH
PRESSURE WILL RETURN FOR THE WEEKEND...WITH CHILLY AND MAINLY DRY
CONDITIONS AS A SHARP UPPER TROUGH ESTABLISHES OVER THE GREAT
LAKES.
&&
.AVIATION /DISCUSSION FOR 211500Z IND TAF UPDATE/...
ISSUED AT 920 AM EST SUN DEC 21 2014
ONLY INSIGNIFICANT MINOR CHANGE TO VFR CONDITIONS.
PREVIOUS DISCUSSION FOLLOWS...
MVFR CONDITIONS POSSIBLE AT TIMES THIS MORNING...OTHERWISE VFR
CONDITIONS EXPECTED.
MUCH OF THE FORECAST AREA REMAINS UNDER MOSTLY CLEAR SKIES WITH A
LIGHT HAZE FROM LINGERING MOISTURE LEFT UNDER THE REMNANT
INVERSION PRODUCING VISIBILITIES IN THE 4-6SM RANGE. STRATUS
REMAINS ACROSS FAR NORTHERN COUNTIES BACK INTO ILLINOIS...BUT HAS
LARGELY SHOWN AN INABILITY TO EXPAND BACK INTO THE REGION OVER THE
LAST SEVERAL HOURS. RAP INDICATING S/SE FLOW IN THE 925-850MB
LAYER WHICH IS LIKELY KEEPING THE THICKER CLOUDS FROM RETURNING TO
THE REGION. MODEL SOUNDINGS AND RH PROGS INDICATE THAT THIS IS
LIKELY TO CONTINUE FOR MOST OF THE DAY WITH INCREASINGLY DRIER AIR
SLIPPING INTO THE BOUNDARY LAYER. GROWING OPTIMISM THAT THE REGION
WILL ENJOY THE MOST SUNSHINE SEEN IN MORE THAN A WEEK. ENOUGH LOW
LEVEL MOISTURE PRESENT THAT COULD SEE SCATTERED STRATOCU DEVELOP
THIS AFTERNOON. SOUTHEAST WINDS WILL BE 5-10KTS TODAY.
MAINLY CLEAR SKIES WILL CONTINUE THIS EVENING WITH A SLOW
INCREASE IN MID LEVEL CLOUDS AS A WARM FRONT APPROACHES FROM THE
WEST. LOW LEVEL RH PROGS SHOW THE LOWER STRATUS DECK IS LIKELY TO
MAKE A RETURN TOWARDS DAYBREAK MONDAY AS WELL WITH INCREASING
MOISTURE ADVECTING INTO THE OHIO VALLEY. LIGHT SOUTHEAST WINDS
WILL CONTINUE OVERNIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....RYAN
AVIATION...RYAN/MK
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
620 AM EST SUN DEC 21 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 301 AM EST SUN DEC 21 2014
A LOW PRESSURE SYSTEM WILL BRING PRECIPITATION TO CENTRAL INDIANA
MONDAY THROUGH WEDNESDAY. AFTER A DRY CHRISTMAS...CHANCES FOR
PRECIPITATION WILL RETURN FRIDAY WITH A WEAKER SYSTEM. WARM AIR
AHEAD OF THE FIRST SYSTEM COULD BRING THE WARMEST READINGS OF
DECEMBER ON TUESDAY...THEN TEMPERATURES WILL RETURN TO CLOSER TO
AVERAGE BY CHRISTMAS.
&&
.NEAR TERM.../TODAY/
ISSUED AT 301 AM EST SUN DEC 21 2014
SKIES HAVE CLEARED ACROSS A GOOD PORTION OF CENTRAL INDIANA EARLY
THIS MORNING...BUT ADDITIONAL LOW CLOUDS WERE NEAR THE
ILLINOIS/INDIANA BORDER AND MOVING SLOWLY EAST.
CLOUD COVER WILL BE TOUGH TO PIN DOWN TODAY AND ONCE AGAIN
CONFIDENCE IS LOW IN THE DETAILS. LOW CLOUDS WILL MARCH INTO WESTERN
AND NORTHWESTERN SECTIONS OF THE AREA THIS MORNING. HOWEVER DRIER
AIR WILL FLOW INTO THE AREA AS WINDS INCREASE OUT OF THE SOUTHEAST.
FOR NOW WILL GO MOSTLY CLOUDY ACROSS THE NORTHWEST FORECAST
AREA...WITH SKIES REMAINING/BECOMING PARTLY CLOUDY ELSEWHERE.
ADJUSTMENTS WILL LIKELY HAVE TO BE MADE LATER THIS MORNING AS THE
EVOLUTION OF THE CLOUDS BECOMES CLEARER.
TEMPERATURES HAVE COOLED MORE THAN EXPECTED EARLY THIS MORNING DUE
TO THE PARTIAL CLEARING. THIS COLD START WILL HELP KEEP TEMPERATURES
BELOW MAV MOS AND CLOSER TO THE MET MOS TODAY.
&&
.SHORT TERM.../TONIGHT THROUGH TUESDAY NIGHT/
ISSUED AT 301 AM EST SUN DEC 21 2014
FOCUS IS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE
SHOWING DIFFERENCES AS WOULD BE EXPECTED WITH THE INCOMING SYSTEM
NOT FULLY SAMPLED YET. CANADIAN LOOKS TOO STRONG WITH THE
SYSTEM...WHILE THE LARGER CHANGE IN SOLUTIONS BETWEEN THE 12Z/00Z
ECMWF LEADS TO LOWER CONFIDENCE IN ITS SOLUTION THIS RUN. WILL USE A
BLEND OF REMAINING MODELS.
CLOUDS WILL INCREASE TONIGHT AS THE SYSTEM APPROACHES FROM THE WEST.
WILL GO A LITTLE WARMER THAN MAV MOS MOST AREAS.
ON MONDAY ISENTROPIC LIFT INCREASES DURING THE AFTERNOON. HOWEVER
DEEPER MOISTURE WILL BE SLOWER TO RETURN THANKS IN PART TO SOUTHEAST
WINDS IN THE LOWER LEVELS. WILL KEEP THE MORNING DRY AND GO WITH
SLIGHT CHANCE TO CHANCE POPS IN THE AFTERNOON. WITH THE CLOUDS AND
SOUTHEAST FLOW...MOS LOOKS TOO WARM FOR HIGHS. WILL CUT SOME.
MONDAY NIGHT AND TUESDAY FORCING RAMPS UP WITH SURFACE FRONT MOVING
INTO THE AREA...850MB WINDS APPROACHING 50KT...AND AN UPPER JET
MOVING IN. THUS WENT LIKELY POPS MOST AREAS BY LATE MONDAY NIGHT AND
LIKELY TO CATEGORICAL POPS ON TUESDAY.
CONTINUED LIKELY TO CATEGORICAL POPS TUESDAY NIGHT AS A SURFACE LOW
RIDES ALONG THE FRONT TOWARD CENTRAL INDIANA. LOOKS LIKE COLDER AIR
WILL BE SLOWER TO ARRIVE THAN PREVIOUSLY THOUGHT...SO WENT ALL RAIN
THROUGH TUESDAY NIGHT.
THE SYSTEM LOOKS TO BRING ENOUGH WARM UP INTO THE AREA ON TUESDAY
FOR HIGHS IN THE LOWER TO MIDDLE 50S...WHICH WILL BE THE WARMEST AIR
THIS MONTH ACROSS THE AREA.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
ISSUED AT 328 AM EST SUN DEC 21 2014
FOCUS FOR THE EXTENDED REMAINS ON POTENTIAL IMPACTS FROM A
STRENGTHENING LOW PRESSURE FOR CHRISTMAS EVE...FOLLOWED BY ANOTHER
STORM SYSTEM BRINGING PRECIPITATION TO THE OHIO VALLEY FRIDAY AND
FRIDAY NIGHT.
LEAD PORTION OF THE POWERFUL UPPER JET APPROACHING THE PACIFIC
NORTHWEST IS STARTING TO BE SAMPLED BY THE RAOB NETWORK.
HOWEVER...THAT HAS DONE LITTLE TO AID IN DEVELOPING A STRONGER
CONSENSUS FOR THE PHASED LOW PRESSURE SYSTEM TO IMPACT THE REGION
WEDNESDAY AS 00Z MODEL SUITE FRANKLY INTRODUCING MORE QUESTIONS THAN
ANSWERS. THE ECMWF AND OP GFS ARE BOTH SLOWER WITH PHASING THE
POLAR AND SUBTROPICAL JETS ALOFT...WITH THE STRENGTHENING UPPER
TROUGH NOT TAKING ON A NEGATIVE TILT UNTIL LATER ON WEDNESDAY AS THE
FEATURE PASSES CENTRAL INDIANA. CONSEQUENTLY THE DEEPENING SURFACE
LOW IS ALSO SLOWER TO TAKE PLACE...OCCURRING OVER THE EASTERN GREAT
LAKES BY EARLY CHRISTMAS MORNING. GFS ENSEMBLE MEMBERS STILL HAVE
QUITE A BIT OF SPREAD AND IT SHOULD BE NOTED THAT A COUPLE MEMBERS
REMAIN DEEPER AND FURTHER WEST WITH THE SURFACE WAVE TRACK.
TAKING INTO CONSIDERATION THAT MODEL SPREAD REMAINS LARGER THAN
DESIRED AND WITH BOTH THE OP GFS AND ECMWF SHIFTING THE LOW TRACK
FURTHER EAST WITH A SLOWER ENERGY PHASE...IT REMAINS PREMATURE TO
LATCH ONTO A SPECIFIC SOLUTION. 12Z RUNS TODAY AND DEFINITELY THE
00Z RUNS TONIGHT SHOULD GET FULL SAMPLING OF THE STRONG UPPER JET
ENERGY COMING INTO THE PACIFIC NORTHWEST. WITH THIS FEATURE SET TO
BE A MAJOR PLAYER INT HE EVOLUTION OF THE STORM SYSTEM...MAY
FINALLY START TO SEE A SLOW INCREASE IN MODEL CONSENSUS.
DO PLAN TO SLOW THE ARRIVAL OF THE COLDER AIR ON WEDNESDAY WITH RAIN
GRADUALLY CHANGING TO SNOW ON WEDNESDAY AFTERNOON AND EVENING.
CANNOT RULE OUT LIGHT ACCUMS BUT ATTEMPT TO EMPLOY ANY MORE DETAIL
WOULD BE FUTILE WITH SUCH TRACK UNCERTAINTY TO THE SURFACE WAVE. IF
THE WAVE TRACKS CLOSER TO THE FORECAST AREA VERSUS FURTHER
EAST...POTENTIAL FOR LIGHT ACCUMS WOULD BE GREATER WITH THE MID
LEVEL DEFORMATION BAND ALIGNING IN SOME MANNER OVER THE FORECAST
AREA. AS IT STANDS...WILL MAINTAIN CHANCE POPS THROUGH WEDNESDAY
NIGHT WITH STRONG WIND GUSTS BEING THE PRIMARY IMPACT...AND
POTENTIAL LIGHT ACCUMS AS A SECONDARY IMPACT. THE THREAT FOR TRAVEL
DISRUPTIONS REMAINS GREATEST DURING THIS TIME PERIOD...AND THOSE
WITH TRAVEL PLANS ARE ENCOURAGED TO MONITOR FORECASTS OVER THE NEXT
FEW DAYS.
CHRISTMAS DAY LOOKS TO BE QUIET AS THE SURFACE WAVE QUICKLY LIFTS
AWAY FROM THE REGION WITH SURFACE RIDGING DEVELOPING OVER THE OHIO
VALLEY. HIGHLY AMPLIFIED FLOW ALOFT WILL MAINTAIN AN ACTIVE
PATTERN...WITH ANOTHER SURFACE LOW TRACKING OUT OF THE CENTRAL
PLAINS AND INTO THE GREAT LAKES ON FRIDAY. STILL A LOT OF MODEL
VARIANCE WITH THIS SYSTEM...AND THAT IS NOT LIKELY TO CHANGE UNTIL
MODELS CAN GAIN A BETTER CONSENSUS ON THE CHRISTMAS EVE STORM. WILL
CARRY CHANCE POPS FOR FRIDAY AND FRIDAY NIGHT...WITH RAIN ON FRIDAY
TRANSITIONING TO LIGHT SNOW FRIDAY NIGHT BEFORE ENDING. SURFACE HIGH
PRESSURE WILL RETURN FOR THE WEEKEND...WITH CHILLY AND MAINLY DRY
CONDITIONS AS A SHARP UPPER TROUGH ESTABLISHES OVER THE GREAT
LAKES.
&&
.AVIATION /DISCUSSION FOR 211200Z TAF ISSUANCE/...
ISSUED AT 620 AM EST SUN DEC 21 2014
MVFR CONDITIONS POSSIBLE AT TIMES THIS MORNING...OTHERWISE VFR
CONDITIONS EXPECTED.
MUCH OF THE FORECAST AREA REMAINS UNDER MOSTLY CLEAR SKIES WITH A
LIGHT HAZE FROM LINGERING MOISTURE LEFT UNDER THE REMNANT
INVERSION PRODUCING VISIBILITIES IN THE 4-6SM RANGE. STRATUS
REMAINS ACROSS FAR NORTHERN COUNTIES BACK INTO ILLINOIS...BUT HAS
LARGELY SHOWN AN INABILITY TO EXPAND BACK INTO THE REGION OVER THE
LAST SEVERAL HOURS. RAP INDICATING S/SE FLOW IN THE 925-850MB
LAYER WHICH IS LIKELY KEEPING THE THICKER CLOUDS FROM RETURNING TO
THE REGION. MODEL SOUNDINGS AND RH PROGS INDICATE THAT THIS IS
LIKELY TO CONTINUE FOR MOST OF THE DAY WITH INCREASINGLY DRIER AIR
SLIPPING INTO THE BOUNDARY LAYER. GROWING OPTIMISM THAT THE REGION
WILL ENJOY THE MOST SUNSHINE SEEN IN MORE THAN A WEEK. ENOUGH LOW
LEVEL MOISTURE PRESENT THAT COULD SEE SCATTERED STRATOCU DEVELOP
THIS AFTERNOON. SOUTHEAST WINDS WILL BE 5-10KTS TODAY.
MAINLY CLEAR SKIES WILL CONTINUE THIS EVENING WITH A SLOW
INCREASE IN MID LEVEL CLOUDS AS A WARM FRONT APPROACHES FROM THE
WEST. LOW LEVEL RH PROGS SHOW THE LOWER STRATUS DECK IS LIKELY TO
MAKE A RETURN TOWARDS DAYBREAK MONDAY AS WELL WITH INCREASING
MOISTURE ADVECTING INTO THE OHIO VALLEY. LIGHT SOUTHEAST WINDS
WILL CONTINUE OVERNIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....RYAN
AVIATION...RYAN
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AREA FORECAST DISCUSSION
NWS TOPEKA KS
1147 AM CST Sun Dec 21 2014
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 233 AM CST SUN DEC 21 2014
08Z water vapor shows a broad upper level trough over the central
part of the country with the upper level jet streak moving inland
over the pacific northwest. At the surface, a trough of low pressure
has gradually be moving out into the northern plains while surface
ridging remained along the gulf coast. An area of stratus could be
seen on satellite moving back north into the forecast area.
For today, the southerly low level flow between the surface trough
to the northwest and ridging southeast of the forecast area should
continue bringing moisture north. Although with the gulf not
completely open due to the ridge axis along the coast, dewpoints are
progged to only increase to around 40 today which makes some since
looking at obs across OK and north TX. This moisture advection
should be enough however to keep the stratus moving north. The NAM
and RAP develop some weak isentropic upglide on the 280 and 285K
surfaces this morning and keep it persisting into the afternoon.
Because of this will maintain a mention of drizzle in the forecast
through the day. Weak large scale forcing and little or no deep
vertical motion to moisten the mid levels leads me to think
measurable precip is less than 20 percent through the day. Cloud
cover should prevent temps from warming much today, so have highs
generally in the mid 40s. Models continue to deepen a shortwave
tonight over NEB. As the wave deepens, models prog some decent PVA
and increasing Q vector convergence to overspread northeast KS. Mid
level lapse rates appear to be near the moist adiabat so there does
not appear to be much in the way of instability. Nevertheless the
increasing forcing and decent moisture already in place should lead
to some rain showers moving into parts of the forecast area late
tonight and through the early morning hours Monday. Have increased
POPs with likely chances for northeast KS and chances diminishing
further south where model progs of forcing are not as strong.
Southerly winds keeping dewpoints in the upper 30s combined with
overcast skies and no radiational cooling should lead to min temps
in the lower 40s for most areas.
.LONG TERM...(Monday through Saturday)
Issued at 233 AM CST SUN DEC 21 2014
Rain showers may linger across east central Kansas Monday as the
upper low slowly rotates over South Dakota. Amount of dry air aloft
differs between guidance and is based on the strength and track of
the upper low. Thinking the dry air intruding may be too progressive
with the NAM, so sided with the slower GFS/ECMWF solution and
therefore mostly cloudy skies for the afternoon. Warm air advection
in the lower levels warms temps to near 50 degrees ahead of the
front. As an upper jet dives southeast from the Rockies, it will dig
the southern stream wave further south and east into Texas while
gradually lifting the upper low northward through Tuesday. In
conjunction with a surface front arriving early Tuesday, embedded
areas of enhanced vorticity wrapping around the upper low may
produce light snow near the Kansas and Nebraska border. Otherwise
most areas remain dry through the afternoon with highs rising a few
degrees from morning lows into the 30s. Amount of stratus will once
again depend on the upper low position. It is possible southern areas
could see lesser cloud cover in the afternoon. In addition, strong
northerly winds are expected Tuesday afternoon between 15 and 25 mph
sustained from the northwest. Gusts near 35 mph are likely
especially for north central Kansas.
Airmass modifies as winds back to the south in advance of a lee
trough Wednesday and Christmas Day. Southerly winds between 10 and
15 mph carry warm, subsident air across the CWA, raising highs from
near 40 on Wednesday to upper 40s for Christmas Day. During this
time, a shortwave trough develops across the western CONUS, bringing
rain and snow to elevated terrain. As it enters the central plains,
questions still remain on the depth and track. Latest ECMWF today
exhibits a very different solution with an open short wave trough
impacting the central plains Thursday evening/Friday, similar to
what the GFS has advertised the past few days. Did not feel
comfortable completely removing pops given the large
inconsistencies, and will therefore leave slight chances until
better consistency is seen one way or the other. A cold air mass
behind the front is more likely, dropping highs Friday and Saturday
in the 30s. Forecast soundings suggest any precip would be in the
form of light snow.
&&
.AVIATION...(For the 18Z TAFs through 18Z Monday Afternoon)
Issued at 1125 AM CST SUN DEC 21 2014
The main challenges for the TAF period will continue to be the
CIG/VIS categories. IFR is expected to persist during the first
half of the period. Winds will be fairly steady but there is
potential for some gusts into the mid 20 mph range as we see some
directional changes come into play. Some uncertainty remains with
light areas of drizzle along with potential for light rain. But
for now, just keeping mention of drizzle. Lower confidence with
the actual CIG/VIS remains with these areas as well, but generally
improving conditions can be expected near the end of the TAF period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...Bowen
AVIATION...Drake
AREA FORECAST DISCUSSION
NWS TOPEKA KS
510 AM CST Sun Dec 21 2014
...AVIATION UPDATE...
.SHORT TERM...(Today and Tonight)
Issued at 233 AM CST SUN DEC 21 2014
08Z water vapor shows a broad upper level trough over the central
part of the country with the upper level jet streak moving inland
over the pacific northwest. At the surface, a trough of low pressure
has gradually be moving out into the northern plains while surface
ridging remained along the gulf coast. An area of stratus could be
seen on satellite moving back north into the forecast area.
For today, the southerly low level flow between the surface trough
to the northwest and ridging southeast of the forecast area should
continue bringing moisture north. Although with the gulf not
completely open due to the ridge axis along the coast, dewpoints are
progged to only increase to around 40 today which makes some since
looking at obs across OK and north TX. This moisture advection
should be enough however to keep the stratus moving north. The NAM
and RAP develop some weak isentropic upglide on the 280 and 285K
surfaces this morning and keep it persisting into the afternoon.
Because of this will maintain a mention of drizzle in the forecast
through the day. Weak large scale forcing and little or no deep
vertical motion to moisten the mid levels leads me to think
measurable precip is less than 20 percent through the day. Cloud
cover should prevent temps from warming much today, so have highs
generally in the mid 40s. Models continue to deepen a shortwave
tonight over NEB. As the wave deepens, models prog some decent PVA
and increasing Q vector convergence to overspread northeast KS. Mid
level lapse rates appear to be near the moist adiabat so there does
not appear to be much in the way of instability. Nevertheless the
increasing forcing and decent moisture already in place should lead
to some rain showers moving into parts of the forecast area late
tonight and through the early morning hours Monday. Have increased
POPs with likely chances for northeast KS and chances diminishing
further south where model progs of forcing are not as strong.
Southerly winds keeping dewpoints in the upper 30s combined with
overcast skies and no radiational cooling should lead to min temps
in the lower 40s for most areas.
.LONG TERM...(Monday through Saturday)
Issued at 233 AM CST SUN DEC 21 2014
Rain showers may linger across east central Kansas Monday as the
upper low slowly rotates over South Dakota. Amount of dry air aloft
differs between guidance and is based on the strength and track of
the upper low. Thinking the dry air intruding may be too progressive
with the NAM, so sided with the slower GFS/ECMWF solution and
therefore mostly cloudy skies for the afternoon. Warm air advection
in the lower levels warms temps to near 50 degrees ahead of the
front. As an upper jet dives southeast from the Rockies, it will dig
the southern stream wave further south and east into Texas while
gradually lifting the upper low northward through Tuesday. In
conjunction with a surface front arriving early Tuesday, embedded
areas of enhanced vorticity wrapping around the upper low may
produce light snow near the Kansas and Nebraska border. Otherwise
most areas remain dry through the afternoon with highs rising a few
degrees from morning lows into the 30s. Amount of stratus will once
again depend on the upper low position. It is possible southern areas
could see lesser cloud cover in the afternoon. In addition, strong
northerly winds are expected Tuesday afternoon between 15 and 25 mph
sustained from the northwest. Gusts near 35 mph are likely
especially for north central Kansas.
Airmass modifies as winds back to the south in advance of a lee
trough Wednesday and Christmas Day. Southerly winds between 10 and
15 mph carry warm, subsident air across the CWA, raising highs from
near 40 on Wednesday to upper 40s for Christmas Day. During this
time, a shortwave trough develops across the western CONUS, bringing
rain and snow to elevated terrain. As it enters the central plains,
questions still remain on the depth and track. Latest ECMWF today
exhibits a very different solution with an open short wave trough
impacting the central plains Thursday evening/Friday, similar to
what the GFS has advertised the past few days. Did not feel
comfortable completely removing pops given the large
inconsistencies, and will therefore leave slight chances until
better consistency is seen one way or the other. A cold air mass
behind the front is more likely, dropping highs Friday and Saturday
in the 30s. Forecast soundings suggest any precip would be in the
form of light snow.
&&
.AVIATION...(For the 12Z TAFs through 12Z Monday Morning)
Issued at 509 AM CST SUN DEC 21 2014
Satellite continues to show MVFR stratus advancing northeast, and
with southerly flow expected to maintain some moisture transport
north think the stratus will hang tough through tonight. Models
continue to show increasing isentropic lift through the afternoon
so drizzle is possible. Confidence in timing is low so opted to
keep VSBY forecast in the MVFR range. However if drizzle develops,
it will likely cause VSBY to be between 1SM and 3SM. Have also
leaned towards keeping CIGS above 1 KFT but there could be some
periods where CIGS drop below 1 KFT. Increasing large scale
forcing late tonight should lead to some -RA moving into the
terminals between 07Z and 09Z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...Bowen
AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS TOPEKA KS
304 AM CST Sun Dec 21 2014
.SHORT TERM...(Today and Tonight)
Issued at 233 AM CST SUN DEC 21 2014
08Z water vapor shows a broad upper level trough over the central
part of the country with the upper level jet streak moving inland
over the pacific northwest. At the surface, a trough of low pressure
has gradually be moving out into the northern plains while surface
ridging remained along the gulf coast. An area of stratus could be
seen on satellite moving back north into the forecast area.
For today, the southerly low level flow between the surface trough
to the northwest and ridging southeast of the forecast area should
continue bringing moisture north. Although with the gulf not
completely open due to the ridge axis along the coast, dewpoints are
progged to only increase to around 40 today which makes some since
looking at obs across OK and north TX. This moisture advection
should be enough however to keep the stratus moving north. The NAM
and RAP develop some weak isentropic upglide on the 280 and 285K
surfaces this morning and keep it persisting into the afternoon.
Because of this will maintain a mention of drizzle in the forecast
through the day. Weak large scale forcing and little or no deep
vertical motion to moisten the mid levels leads me to think
measurable precip is less than 20 percent through the day. Cloud
cover should prevent temps from warming much today, so have highs
generally in the mid 40s. Models continue to deepen a shortwave
tonight over NEB. As the wave deepens, models prog some decent PVA
and increasing Q vector convergence to overspread northeast KS. Mid
level lapse rates appear to be near the moist adiabat so there does
not appear to be much in the way of instability. Nevertheless the
increasing forcing and decent moisture already in place should lead
to some rain showers moving into parts of the forecast area late
tonight and through the early morning hours Monday. Have increased
POPs with likely chances for northeast KS and chances diminishing
further south where model progs of forcing are not as strong.
Southerly winds keeping dewpoints in the upper 30s combined with
overcast skies and no radiational cooling should lead to min temps
in the lower 40s for most areas.
.LONG TERM...(Monday through Saturday)
Issued at 233 AM CST SUN DEC 21 2014
Rain showers may linger across east central Kansas Monday as the
upper low slowly rotates over South Dakota. Amount of dry air aloft
differs between guidance and is based on the strength and track of
the upper low. Thinking the dry air intruding may be too progressive
with the NAM, so sided with the slower GFS/ECMWF solution and
therefore mostly cloudy skies for the afternoon. Warm air advection
in the lower levels warms temps to near 50 degrees ahead of the
front. As an upper jet dives southeast from the Rockies, it will dig
the southern stream wave further south and east into Texas while
gradually lifting the upper low northward through Tuesday. In
conjunction with a surface front arriving early Tuesday, embedded
areas of enhanced vorticity wrapping around the upper low may
produce light snow near the Kansas and Nebraska border. Otherwise
most areas remain dry through the afternoon with highs rising a few
degrees from morning lows into the 30s. Amount of stratus will once
again depend on the upper low position. It is possible southern areas
could see lesser cloud cover in the afternoon. In addition, strong
northerly winds are expected Tuesday afternoon between 15 and 25 mph
sustained from the northwest. Gusts near 35 mph are likely
especially for north central Kansas.
Airmass modifies as winds back to the south in advance of a lee
trough Wednesday and Christmas Day. Southerly winds between 10 and
15 mph carry warm, subsident air across the CWA, raising highs from
near 40 on Wednesday to upper 40s for Christmas Day. During this
time, a shortwave trough develops across the western CONUS, bringing
rain and snow to elevated terrain. As it enters the central plains,
questions still remain on the depth and track. Latest ECMWF today
exhibits a very different solution with an open short wave trough
impacting the central plains Thursday evening/Friday, similar to
what the GFS has advertised the past few days. Did not feel
comfortable completely removing pops given the large
inconsistencies, and will therefore leave slight chances until
better consistency is seen one way or the other. A cold air mass
behind the front is more likely, dropping highs Friday and Saturday
in the 30s. Forecast soundings suggest any precip would be in the
form of light snow.
&&
.AVIATION...(For the 06Z TAFs through 06Z Sunday Night)
Issued at 1142 PM CST SAT DEC 20 2014
MVFR cigs have moved into MHK and are expected to move into
TOP/FOE in the next few hours. Could see a few breaks but think
these cigs will prevail through the day on Sunday. Did not add
drizzle to terminals as lift is weak and may remain in obs as BR.
Second system approaches right behind first to keep clouds and
possibly light precipitation going into the next overnight period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...Bowen
AVIATION...67
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1004 PM EST Mon Dec 22 2014
...Forecast Update...
Issued at 1000 PM EST Mon Dec 22 2014
Good area of rain continues to move northeast over west-central to
north-central KY and south-central IN at this time. This is in
response to strong shortwave tilting negatively to the south and
east of main upper low over central Plains. This shortwave trough
over MO will lift rapidly northeast overnight. The trough is
enhancing forcing over the lower Ohio Valley. Looking at model
soundings and Nashville`s 00 UTC observed sounding, there is a bit
of elevated instability. The combination of forcing and less stable
air aloft is leading to good ascent ahead of the shortwave and the
area of rain, some moderate to isolated heavy, in our forecast area.
As the shortwave lifts northeast, so will the rain. Given the weak
instability aloft and given a few specks of 50 dBZ on radar here and
there, plus a few lightning strikes earlier, will include a slight
chance of thunder overnight, also supported by a 40 kt low-level
jet. Will carry categorical POPs with this feature overnight but
rain should then diminish somewhat toward morning, as supported by
latest HRRR run and as suggested by 00z NAM. Nevertheless, scattered
showers still are expected. Temps won`t dip much overnight, perhaps
a couple degrees then steady. Showers should then pick up again
during the day on Tuesday over central KY.
Issued at 650 PM EST Mon Dec 22 2014
Quick update for latest trends. Central KY and south-central IN has
been largely devoid of precip other than a few sprinkles early this
evening. However, better area of showers is developing and moving
northeast over western parts of KY and TN at this time, with some
briefly heavier cells. This is in response to forcing associated
with tail end of shortwave trough entering MO as the trough rotates
around the underside of the upper low over the central Plains.
As this shortwave moves northeast tonight, the area of showers will
lift northeast as well, spreading across the western half of our
forecast area. The Bluegrass region may stay on eastern fringe of
precip with only scattered showers. Surface winds will pick up a bit
this evening as well, especially along the I-65 corridor in response
to the shortwave rotating through to our west and northwest. This
will keep temps pretty much in check this evening.
.SHORT TERM (Now through Tuesday Night)...
Issued at 310 PM EST Mon Dec 22 2014
Deep upper low is just about to close off over the Northern Plains
this afternoon, with deep=layer S-SW flow increasing over the
Mississippi and Ohio Valleys. This pattern will result in mild but
unsettled weather over the next 36 hrs or so, as a series of
disturbances will touch off rounds of showers.
Moisture transport is just getting established, so the main precip
shield associated with the lead disturbance has remained confined
mainly to the Wabash Valley and points west, with very little in the
way of precip over central Kentucky or southern Indiana. A
smattering of showers did develop over northern Alabama, but not
showing much organization as it lifts through Middle Tennessee.
Still expecting precip to blossom tonight as additional upper waves
interact with a 40-45 kt low-level jet, but QPF looks fairly modest.
Therefore will still carry categorical POPs, even though confidence
in getting any substantial rain amounts is decreasing. An isolated
rumble of thunder still can`t be completely ruled out, but continues
to look less likely as this system appears to come at us in pieces.
Therefore will go forward without mention of thunder at this time.
By daybreak the best feed of deep moisture will be shunted to our
north and east, so would expect a break of a few hours in the precip
Tuesday morning. However the next wave will take shape late in the
day, spreading rain back in from south to north late afternoon/early
evening. Deepening surface low still progged to run up between the
I-65/I-75 corridors, with tremendous bust potential depending on
exactly where it tracks. Categorical POPs and steady temps in the
50s along/east of the track, while farther west, precip chances are
barely 50-60% and temps could drop into the lower 40s by Wednesday
morning. There will be a tight gradient in between but the placement
is a little iffy, and for now we will assume that to be somewhere
near I-65.
.LONG TERM (Wednesday through Monday)...
Issued at 300 PM EST Mon Dec 22 2014
An active long term period with the main forecast challenge being
temperatures and precipitation timing/types Christmas Eve through
Christmas morning, followed by more precipitation chances this
weekend.
The 22.12z guidance is trending toward a similar solution with the
main surface low track Wednesday morning. Outside of the NAM, which
was an eastern outlier, the ECMWF/GFS/GEM show a strengthening low
lifting along a Nashville to Louisville to Indianapolis track during
the course of the day. A time trend analysis shows this is a slight
shift west and about 3-6 hours later than the previous consensus.
The impacts this has to precipitation timing and type were very
minimal, as there has been good consensus for steady rain to move
across the region during the course of the day. However, the change
does allow for warmer air to move through central/eastern Kentucky
and as a result, high temperatures were increased to the mid/upper
50s from the Cumberland to Bluegrass region, including the Lexington
metro area. For the Louisville area, the tighter baroclinic zone
will be right along the I-65 corridor, making Wednesday morning
temperatures difficult to pinpoint at this time. Nonetheless, the
area should warm into the low 50s before cold advection kicks in and
temperatures crash into the low/mid 40s by afternoon. Western
forecast area should see the coolest readings, likely stuck in the
upper 40s, then falling into the upper 30s by mid afternoon.
The main message/impact for the public will be a wet, unsettled
Christmas Eve with falling temperatures during the afternoon. It`ll
also be windy, both ahead and behind the surface low. Not ideal
holiday travel conditions, even if it`s just all liquid.
Soundings show a potential changeover from rain to snow west of I-65
during the evening hours /after 7 pm/. However, the greater
frontogenetical forcing and deformation precipitation band should be
west of the forecast area and we`ll be dealing with scattered, light
precipitation. Will continue to advertise a rain to rain/snow mix to
light snow during the nighttime hours. Little accumulations likely
as wet/warm surfaces and temperatures in the low/mid 30s will limit
accumulations. For Christmas, plan on clearing skies west to east as
a Pacific airmass high pressure quickly builds in from the
southwest. Temperatures will be around normal in the mid 40s.
The weekend forecast has some uncertainty as the whole upper level
flow remains amplified and active across the CONUS. At least
initially, there is some consensus that a surface low lifts through
the Great Lakes Friday night, dragging a cold front through the
local area Saturday. 30-40 percent rain chances look reasonable at
this time. Differences arise between the ECMWF/GFS/GEM as the 22.12z
ECMWF/GEM camp develop a secondary low along the Texas gulf coast
Saturday night, lifting it toward eastern Tennessee Sunday. This
would spread precipitation back across the area. Temperature
profiles this time would support a rain/snow mix for the northwest
half of the forecast area. However, the forecast details, including
any specific storm system/track, beyond Saturday have low confidence
as there are a wide range of solutions in this type of upper level
pattern. Next week looks to featuer similar uncertainity as both
ECMWF and GFS show varying storm systems to possibly impact the
area. An active stretch through the end of the year.
&&
.AVIATION (00Z TAF Update)...
Issued at 630 PM EST Mon Dec 22 2014
Shortwave trough rotating east across KS and MO at this time will
lift northeast rapidly tonight, which will increase low-level winds
for a time this evening and overnight until shortwave passes by. As
a result, expect surface winds to increase to 10-15 mph this evening
at TAF sites, especially at BWG and SDF. Winds 2-3 kft off the
surface should increase to about 40-45 kts at these locations as
well. As a result, will continue with mention of low-level wind
shear at BWG and SDF late this evening and overnight, with winds
diminishing in the 10-12 UTC time frame. It looks like LEX will be
less affected, still with some increasing winds, but not wind shear
criteria as LEX will be more displaced from influence of shortwave.
Otherwise, area of precip over western KY at this time should expand
northeast later this evening with forcing from the wave. This will
affect SDF and BWG the most. This passes by late tonight, with just
some lighter sct showers by morning before more showers ramp up and
expand in coverage during the day Tuesday.
As for cigs, lowest cigs (low MVFR to possibly IFR) will affect SDF
and BWG late this evening and overnight, continuing on Tuesday,
with LEX cigs a bit higher, displaced from the best low-level
saturation.
Surface winds on Tuesday will be a bit tricky with south to
southeast flow, then possibly backing some during the day or even
becoming variable as a surface trough becomes established roughly in
the BWG to SDF corridor. Winds at LEX should stay south to southeast.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........TWF
Short Term.....RAS
Long Term......ZBT
Aviation.......TWF
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1009 AM EST SUN DEC 21 2014
.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OVER THE AREA THIS AFTERNOON AND
TONIGHT THEN SLOWLY MOVE TO THE EAST MONDAY INTO TUESDAY. A LARGE
AREA OF LOW PRESSURE WILL APPROACH TUESDAY NIGHT THEN TRACK TO OUR
WEST WEDNESDAY INTO THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE...PATCHY FREEZING DRIZZLE HAS ENDED W/MAINLY CLOUDY
CONDITION. CLOUDS WILL HANG ON THE STRONG INVERSION IN PLACE
THROUGH THE AFTERNOON. TEMPS NEEDED ADJUSTMENT TO BRING THEM UP
W/SOME WEAK WAA OCCURRING PER THE LATEST 12Z UA. ADJUSTED THE
AFTERNOON MAXES A FEW DEGREES ACROSS THE BOARD. NORLUN TYPE SETUP
LOOKS TO BE IN ORDER W/LOW WELL S OF THE CWA AND INVERTED TROF
SETTING UP. ADJUSTED THE POPS TO ACCOUNT FOR THIS SETUP FOLLOWING
THE MESOSCALE NAM AND RAP GUIDANCE. THIS FEATURE WILL BE
RESPONSIBLE FOR SOME LIGHT SNOW OR PERHAPS SOME FREEZING DRIZZLE.
WILL BE MONITORING THIS SITUATION THROUGH THE AFTERNOON.
PREVIOUS DISCUSSION...
THE STRONG SUBSIDENCE INVERSION CONTINUES THROUGH THE PERIOD WITH
CLOUDY SKIES AND STEADY TO GRADUALLY MODERATING TEMPERATURES. THE
VERY SHALLOW COLUMN OF MOISTURE WILL TOP OUT NEAR H900 IN NORTHERN
ZONES AND UP TO H850 NEAR THE COAST. INSTABILITY WITHIN THE COLUMN
WILL PRODUCE PATCHY FREEZING DRIZZLE AND FLURRIES ACROSS THE
FORECAST AREA THROUGH TONIGHT. THE ONLY SYNOPTIC SCALE FEATURE
RESOLVED BY NWP WILL BE A WEAK INVERTED TROUGH IN CONCERT WITH AN
UPPER LOW OVER SOUTHERN NEW ENGLAND TODAY. AFFECTS FROM THIS
SYSTEM ARE EXPECTED TO STAY SOUTH OF THE FORECAST AREA...BUT THERE
MAY BE JUST ENOUGH MOISTURE AND LIFT TO GENERATE MEASURABLE
PRECIP IN SOUTHERN HANCOCK COUNTY...MOSTLY IN THE OUTER ISLANDS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
HIGH PRESSURE WILL REMAIN OVER THE AREA MONDAY. HOWEVER, A STRONG
LOW LEVEL INVERSION WILL LIKELY HOLD THE LOW STRATUS CLOUDS IN PLACE
ACROSS MOST OF THE AREA. THE HIGH WILL GRADUALLY SLIDE EAST INTO THE
MARITIMES MONDAY NIGHT INTO TUESDAY. A BIT OF LOW LEVEL MOISTURE
PUSHING ONSHORE JUST SOUTH AND WEST OF THE HIGH MAY BRING SOME
PATCHY LIGHT SNOW INLAND, AND RAIN ALONG THE COAST, TO SOUTHWESTERN
PARTS OF THE REGION MONDAY NIGHT INTO TUESDAY. OTHERWISE, MOST OF
THE AREA WILL JUST REMAIN OVERCAST THROUGH TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
OUR FOCUS GOING INTO THE MIDWEEK PERIOD WILL BE ON A LARGE AND
COMPLEX STORM SYSTEM LIFTING THROUGH THE MIDWEST, WELL TO OUR WEST.
CLOUDS WILL THICKEN TUESDAY NIGHT AND SOME LIGHT RAIN MAY BEGIN TO
SPREAD ACROSS THE AREA BY WEDNESDAY MORNING. BOUNDARY LAYER TEMPS
ARE EXPECTED TO SUPPORT ALL RAIN ACROSS THE AREA, BUT SOME RESIDUAL
LOW LEVEL COLD AIR MAY STILL BE IN PLACE ACROSS SOME NORTHERN SITES
SO WILL MENTION CHC FREEZING RAIN WEDNESDAY MORNING OVER THE NORTH.
RAIN WILL INCREASE IN INTENSITY WEDNESDAY AS THE STORM CENTER LIFTS
THROUGH THE GREAT LAKES. WINDS WILL INCREASE OUT OF THE SOUTHEAST.
MODEL GUIDANCE DIFFERS ON HOW STRONG THE WINDS WILL BE, BUT THE
BEST CHANCE OF HAVING SOME STRONG WINDS WILL BE ALONG DOWNEAST
AREAS, ESPECIALLY NEAR THE COAST, LATE WEDNESDAY INTO WEDNESDAY
NIGHT. RAIN AND WIND WILL CONTINUE WEDNESDAY NIGHT INTO THURSDAY
MORNING AS THE LOW LIFTS TO OUR WEST. THE LOW WILL THEN PULL AN
OCCLUDED FRONT ACROSS THE REGION THURSDAY AFTERNOON BRINGING SOME
DRYING. MAINLY DRY WEATHER IS LIKELY FRIDAY AS HIGH PRESSURE
BUILDS SOUTH OF THE AREA. A WEAK FRONTAL BOUNDARY, POSSIBLY
SUPPORTING A SMALL WAVE OF LOW PRESSURE, WILL THEN BRING A CHANCE
FOR SOME LIGHT SNOW NORTH AND SOME SHOWERS DOWNEAST ON SATURDAY.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: EXPECT PREDOMINATELY MVFR CIGS FOR ALL TERMINALS
THROUGH THE PERIOD.
SHORT TERM:
IFR CONDITIONS WILL LIKELY CONTINUE MONDAY INTO TUESDAY AS A DECK OF
LOW STRATUS CLOUDS REMAINS ACROSS THE AREA. IFR CONDITIONS WILL THEN
PERSIST WEDNESDAY INTO EARLY THURSDAY WITH RAIN AND WIND AND
POSSIBLY SOME LOW LEVEL WIND SHEAR IN STRONG SOUTHERLY WINDS.
CONDITIONS MAY IMPROVE LATE THURSDAY FOLLOWING A FRONTAL PASSAGE.
&&
.MARINE...
NEAR TERM: WINDS AND SEAS WILL CONTINUE TO DECREASE UNDER THE
INFLUENCE OF HIGH PRESSURE. NO ADVISORIES ARE ANTICIPATED.
SHORT TERM:
LIGHT EAST TO NORTHEAST WINDS WILL PERSIST MONDAY INTO TUESDAY AS
HIGH PRESSURE SLIDES INTO THE MARITIMES. WINDS AND SEAS WILL
INCREASE OUT OF THE SOUTHEAST WEDNESDAY AS A STRONG STORM LIFTS
NORTHWEST OF THE AREA, LIKELY REQUIRING A GALE OR A STORM WARNING
WEDNESDAY INTO WEDNESDAY NIGHT. GUSTY WINDS WILL BECOME WESTERLY ON
THURSDAY FOLLOWING A FRONTAL PASSAGE.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT/MCW
SHORT TERM...BLOOMER
LONG TERM...BLOOMER
AVIATION...HEWITT/MCW/BLOOMER
MARINE...HEWITT/MCW/BLOOMER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1233 PM EST SUN DEC 21 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 434 AM EST SUN DEC 21 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A RELATIVELY WEAK
W-E FLOW ALOFT EXTENDING FROM THE NRN PLAINS INTO THE NW GREAT LKS.
THERE IS EXTENSIVE LO CLD COVER OVER THE UPR MIDWEST/NW GREAT LKS
CONSISTENT WITH THE MOIST AIR LLVL AIR ADVECTED TO THE N BY THE S
WIND BTWN SFC HI PRES IN THE CNDN MARITIMES AND LOWER PRES IN THE
NRN PLAINS. LOCAL 00Z RAOBS SHOW THIS MSTR EXTENDS UP TO H85 TO AS
HI AS H7. ALTHOUGH THERE IS A WEAK SHRTWV PASSING OVER UPR MI EARLY
THIS MRNG...MID LVL DRYNESS SHOWN ON THE RAOBS ABOVE THE LOWER LVL
MSTR AND ABSENCE OF DYNAMIC FORCING HAS PREVENTED ANY PCPN. THERE IS
ANOTHER MORE VIGOROUS SHRTWV/SHARPER DPVA AND DEEP LYR QVECTOR CNVGC
MOVING INTO FAR NW MN...BUT RATHER DRY MID LVL AIR TO THE W AS WELL
IS LIMITING THE ACCOMPANYING PCPN TO SOME LIGHT SN OVER NCENTRAL MN.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON THE POTENTIAL FOR SOME
FREEZING DZ TODAY AS THE STEADY S LLVL FLOW ADVECTS SOMEWHAT HIER
DEWPTS INTO THE UPR LKS. FOCUS FOR LATER TDAY/TNGT SHIFTS TO THE CHC
FOR STEADY SN AS SHRTWV/QVECTOR CNVGC NOW IN NW MN DRIFTS TOWARD UPR
MI.
TODAY...MODELS SHOW H95-9 S WINDS INCRSG THRU THE DAY AND UP TO 30
KTS BY 00Z MON. AS THESE STRONGER WINDS TAP THE HIER NEAR SFC
SPECIFIC HUMIDITY...MOST OF THE MODELS GENERATE SOME SPOTTY LIGHT
PCPN OVER MAINLY THE SCENTRAL THIS MRNG INTO THE AFTN. SINCE THE
DEPTH OF THE LLVL MOIST LYR DOES NOT REACH THE DGZ...WL MAINTAIN THE
MENTION OF SOME FREEZING DZ OVER THE SCENTRAL WHERE THE LLVL SSE
FLOW UPSLOPES AND WHERE THE LLVLS ARE LIKELY TO BE SUFFICIENTLY
MOIST TO SUPPORT SOME DZ. BUT AS THE SHRTWV NOW MOVING THRU NW MN
MOVES ENE INTO NW ONTARIO AND TAIL OF DEEP LYR QVECTOR CNVGC/DEEPER
MSTR ARRIVE W-E THIS AFTN...EXPECT SOME LIGHT SN TO PUSH INTO THE
AREA. BUT OVERALL DRYNESS OF THE MID LVLS SHOULD LIMIT THE INTENSITY
OF THIS PCPN. THE PCPN OVER THE SCENTRAL AND E MAY REMAIN IN THE
FORM OF FREEZING DZ/DZ/FLURRIES WELL INTO THE AFTN AS THE STRONGER
FORCING/DEEPER MOISTENING REMAIN TO THE W. HI TEMPS TODAY WL BE
ABOVE NORMAL AND IN THE 30S.
TNGT...AS THE SHRTWV IN ONTARIO CONTINUES TO THE NE AND AWAY FM UPR
MI...THE BULK OF THE DEEP LYR FORCING IS FCST TO LIFT TO THE NE. SO
AFTER A PERIOD OF LIKELY POPS MAINLY OVER THE W AND CENTRAL IN THE
EVNG...EXPECT DIMINISHING POPS OVERNGT. BULK OF THE SHORTER RANGE
MODELS INDICATE THE HEAVIER PCPN WL BE OVER THE CENTRAL CWA...WHERE
UPSLOPE SSE FLOW OFF LK MI WL COINCIDE WITH THE SHARPER DEEP LYR
QVECTOR DVGC. MAIN CONCERN REMAINS HOW MUCH DRY MID LVL DRY AIR IN
PLACE WL LIMIT PCPN TOTALS. BUT EXPECTED QPF UP TO 0.15 INCH IN THIS
AREA WL SUPPORT UP TO 2 INCHES OF SN. WITH OVC SKIES AND A STEADY S
WIND...THERE WL BE LTL DIURNAL DROP IN TEMP AND WELL ABV NORMAL LOWS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 434 AM EST SUN DEC 21 2014
COMPLICATED FORECAST STILL IN FULL SWING. DIFFERENCES ABOUND IN THE
MODELS...BOTH WITH THE INITIAL WEAKENING CLOSED LOW/SFC LOW DRIFTING
OUT OF THE NORTHERN PLAINS MONDAY AFTN THROUGH TUESDAY...THEN AGAIN
WITH SOUTHERN STREAM SFC LOW LIFTING NORTHWARD OVER THE GREAT LAKES
WEDNESDAY INTO CHRISTMAS DAY. SOME BREAKING NEWS THERE IN TERMS OF
MODEL TRENDS FOR SURE.
SHORTWAVE TROUGH WILL BE HEADING OVER THE NORTHERN PLAINS ON MONDAY
MORNING. SNOW THAT DEVELOPS LATER TODAY OVER UPPER LAKES WELL AHEAD
OF THIS SYSTEM DRIVEN BY LEAD SHORTWAVE/H85-H5 Q-VECTOR CONVERGENCE
AND H85-H7 MOISTURE TRANSPORT SHOULD BE IN PROCESS OF LIFTING OUT OF
UPR MICHIGAN ON MONDAY MORNING. SOUNDINGS SHOW RISK OF FZDZ IN WAKE
OF DEPARTING LGT SNOW ON MONDAY MORNING WITH DRY LAYER H85-H6 BUT
MOIST UPSLOPE SSE FLOW OFF LK MICHIGAN BLO H85. BY MONDAY AFTN OR
MON EVENING...SOUNDINGS MOISTEN MID-LEVELS IN RESPONSE TO SHORTWAVE
AND SFC LOW MOVING OVER THE NORTHERN PLAINS. SLOWER TREND SHOWS UP
IN THE LAST TWO RUNS OF THE ECMWF WITH THIS SYSTEM INTO TUESDAY AND
THAT PUTS THE ECMWF AT ODDS WITH THE GFS/NAM IDEAS WITH REGARD TO
SPEED OF SYSTEM AND LOCATION OF HEAVIER QPF. MAIN ISSUE IS GFS/NAM
SHOWING FARTHER NORTH H85-H7 LOW CENTER/DRY SLOT COMPARED TO FARTHER
SW ECMWF. GEM-REGIONAL SIMILAR TO ECMWF BUT NOT AS FAR NORTH WITH
HEAVIER QPF ON TUESDAY. USED A GENERAL CONSENSUS...BUT ULTIMATELY
WEIGHTED QPF INTO TUESDAY MORE TOWARD SLOWER/WETTER ECMWF/CANADIAN.
BASED ON 1000-850MB THICKNESS AND NAM SOUNDINGS...APPEARS THAT PTYPE
FOR AT LEAST TUESDAY MORNING SHOULD BE MAINLY SNOW JUST INLAND FM LK
MICHIGAN AND OVER REST OF CWA. BY AFTN THOUGH...NEAR SFC LAYER WARMS
ENOUGH TO RESULT IN MIX OF RAIN AND SNOW OVER MOST CWA...WITH MAINLY
RAIN EXPECTED OVER EAST HALF. A NARROW AND ELEVATED DGZ AROUND 600MB
WITH TEMPS WARMER THAN -10C BLO POINTS TO LOW SLR/S. EVEN SO...SEEMS
THAT INTERIOR SECTIONS OF CNTRL UPR MICHIGAN NEAR THE WI BORDER AND
MAYBE INTO THE INTERIOR SOUTH CNTRL...JUST INLAND FM KESC AND KMNM
COULD END UP WITH THE NEAR ADVY SNOW AMOUNTS MONDAY NIGHT INTO
TUESDAY MORNING. NEED 3 INCHES OF WET SLOPPY SNOW /SLR/S LESS THAN
20:1/ IN 12 HRS TO MEET ADVISORY CRITERIA. WILL BE SOMETHING TO
WATCH...BUT BASED ON CURRENT SPREAD OF SOLUTIONS...WILL PROBABLY
WILL NOT HAVE THIS PINNED DOWN UNTIL WITHIN 12-24 HR OF THE ARRIVAL
OF STEADIER SNOW.
EVENTUALLY AS TUESDAY WEARS ON REMNANT OF UPR/SFC LOWS SLIDE ACROSS
UPR MICHIGAN AND DRY SLOT WILL BECOME BIGGER FACTOR. ATTN BY LATE
TUESDAY INTO TUESDAY NIGHT WILL BE TO THE SOUTH AS STRONGER SHORTWAVE
IN SOUTHERN STREAM WILL BE POISED TO LIFT NORTH OVER THE TENNESSEE
AND OHIO VALLEYS. FOR BETTER OR WORSE...THIS PART OF THE FORECAST
HAS BECOME EVEN MORE MUDDLED THAN THE LAST COUPLE DAYS.
THE UPSHOT OF THE TRENDS FM THE 00Z GFS AND PARALLEL GFS/UKMET AND
ECMWF IS THAT THE STRONG SFC LOW THAT WAS FORECAST TO IMPACT THE
REGION IS NOT FORMING UNTIL IT IS WELL TO THE EAST OF HERE. THIS
ESSENTIALLY TURNS THIS SYSTEM INTO A NON-EVENT FOR THE UPPER GREAT
LAKES AS H85-H3 DPVA STAYS OVER LOWER LAKES AND PRIME SURGE OF STRONG
MOISTURE ADVECTION AND ASSOCIATED HEAVIER QPF ALSO STAYS MORE OVER
LOWER GREAT LAKES. NOT SAYING THAT IS EXACTLY WHAT WILL HAPPEN BUT IT
IS WHAT MAJORITY OF MODELS NOW SHOW. UPPER GREAT LAKES WOULD BE
AFFECTED BY A MOISTURE STARVED NORTHERN STREAM SHORTWAVE AND WEAK
TROUGH. NOT COLD AT ALL WITH H85 TEMPS AS THIS CROSSES LATE WEDNESDAY
INTO CHRISTMAS WARMER THAN -8C...SO IMPACT FM THAT SYSTEM WOULD BE
MINIMAL. OBVIOUSLY...THIS IS A FAR CRY FM BLOCKBUSTER STORM MODELS
HAD BEEN ADVERTISING AT LEAST FOR MAJORITY OF RUNS IN RECENT DAYS.
CURRENTLY THE ONLY MODEL THAT SHOWS THE STRONG STORM IS THE 00Z
CANADIAN WHICH HAS MAINTAINED CONTINUITY AS IT PEGS A 970MB LOW AT
00Z ON THURSDAY OVER NORTHERN LOWER MICHIGAN HEADING NORTH TOWARD
JAMES BAY ON THURSDAY. CONCERNED THAT TREND THAT GFS STARTED ON
SATURDAY HAS NOW BEEN LATCHED ON TO BY ECMWF WHICH HAD BEEN VERY
CONSISTENT UP TO THIS RUN. VERY STRIKING TO SEE THE NCEP FAVORED
UKMET SOLUTION CHANGE FROM A 968MB LOW OVER LK HURON AT 00Z THURSDAY
TO A 1004MB RIDGE WITH LATEST RUN VALID AT THE SAME TIME. WHOLE
FORECAST SITUATION IS HIGHLY CHANGEABLE...AND CANNOT RULE OUT THAT
MODELS WILL TREND BACK TO THE STRONG STORM. SHORTWAVE AND JET ENERGY
THAT ALL THIS EMERGES OUT OF IS JUST ENTERING PACIFIC NORTHWEST THIS
MORNING SO IT WILL NOW BE SAMPLED WELL FM HERE ON OUT. WE WILL SEE IF
THIS AFFECTS FOLLOWING MODEL SOLUTIONS. LIKELY IT WILL...BUT TO WHAT
DEGREE IS THE QUESTION.
GIVEN THE BIG CHANGES...LEANED HEAVILY ON CONSENSUS OF MODELS FOR
WEDNESDAY AND BEYOND. STILL APPEARS TO TURN COLDER BY NEXT WEEKEND
BEHIND THIS SYSTEM WITH DECENT SHOT OF LAKE EFFECT SNOW SHOWERS FOR
AREAS FAVORED BY NW WINDS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY MORNING)
ISSUED AT 1233 PM EST SUN DEC 21 2014
AN APPROACHING UPPER LEVEL DISTURBACE FROM THE WEST WILL ALLOW LIGHT
SNOW TO DEVELOP ACROSS UPPER MICHIGAN LATE THIS AFTERNOON AND EARLY
EVENING. CIGS AT CMX AND SAW WILL LOWER INTO THE IFR RANGE DURING
THIS TIME. DOWNSLOPING SOUTHERLY WINDS AT IWD SHOULD KEEP CIGS THERE
ON THE FENCE BETWEEN MVFR AND IFR. LIGHT SNOW WILL TAPER OFF
OVERNIGHT TONIGHT BUT ENOUGH LOW LEVEL MOISTURE WILL KEEP CIGS AT
CMX AND SAW AT THE MVFR/IFR THRESHOLD THROUGH MONDAY MORNING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 434 AM EST SUN DEC 21 2014
S-SE WINDS INCREASE THIS AFTN AND SHOULD REMAIN UP TO 30 KTS OVER
MAINLY THE EAST HALF OF LK SUPERIOR TONIGHT THROUGH MONDAY AS A LOW
PRESSURE SYSTEM MOVES FM THE NORTHERN PLAINS TO THE WESTERN GREAT
LAKES. AS THE LOW LIFTS OVER THE AREA ON TUESDAY...WINDS WILL SETTLE
DOWN BLO 20 KTS. NEXT CHANCE FOR STRONGER WINDS DEVELOPS LATE
WEDNESDAY INTO THURSDAY AS LOW PRESSURE SYSTEM DEEPENS EAST OF LK
SUPERIOR. WNW-NW WINDS OF 30 KTS WITH A FEW GALE GUSTS TO 35 KTS
FAIRLY CERTAIN...BUT CONFIDENCE IN SYSTEM PRODUCING STRONGER GALES
ON THURSDAY IS NOT AS HIGH AS THE LAST COUPLE DAYS AS THE TREND IS
NOW FOR A WEAKER SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...MZ
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
712 AM EST SUN DEC 21 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 434 AM EST SUN DEC 21 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A RELATIVELY WEAK
W-E FLOW ALOFT EXTENDING FROM THE NRN PLAINS INTO THE NW GREAT LKS.
THERE IS EXTENSIVE LO CLD COVER OVER THE UPR MIDWEST/NW GREAT LKS
CONSISTENT WITH THE MOIST AIR LLVL AIR ADVECTED TO THE N BY THE S
WIND BTWN SFC HI PRES IN THE CNDN MARITIMES AND LOWER PRES IN THE
NRN PLAINS. LOCAL 00Z RAOBS SHOW THIS MSTR EXTENDS UP TO H85 TO AS
HI AS H7. ALTHOUGH THERE IS A WEAK SHRTWV PASSING OVER UPR MI EARLY
THIS MRNG...MID LVL DRYNESS SHOWN ON THE RAOBS ABOVE THE LOWER LVL
MSTR AND ABSENCE OF DYNAMIC FORCING HAS PREVENTED ANY PCPN. THERE IS
ANOTHER MORE VIGOROUS SHRTWV/SHARPER DPVA AND DEEP LYR QVECTOR CNVGC
MOVING INTO FAR NW MN...BUT RATHER DRY MID LVL AIR TO THE W AS WELL
IS LIMITING THE ACCOMPANYING PCPN TO SOME LIGHT SN OVER NCENTRAL MN.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON THE POTENTIAL FOR SOME
FREEZING DZ TODAY AS THE STEADY S LLVL FLOW ADVECTS SOMEWHAT HIER
DEWPTS INTO THE UPR LKS. FOCUS FOR LATER TDAY/TNGT SHIFTS TO THE CHC
FOR STEADY SN AS SHRTWV/QVECTOR CNVGC NOW IN NW MN DRIFTS TOWARD UPR
MI.
TODAY...MODELS SHOW H95-9 S WINDS INCRSG THRU THE DAY AND UP TO 30
KTS BY 00Z MON. AS THESE STRONGER WINDS TAP THE HIER NEAR SFC
SPECIFIC HUMIDITY...MOST OF THE MODELS GENERATE SOME SPOTTY LIGHT
PCPN OVER MAINLY THE SCENTRAL THIS MRNG INTO THE AFTN. SINCE THE
DEPTH OF THE LLVL MOIST LYR DOES NOT REACH THE DGZ...WL MAINTAIN THE
MENTION OF SOME FREEZING DZ OVER THE SCENTRAL WHERE THE LLVL SSE
FLOW UPSLOPES AND WHERE THE LLVLS ARE LIKELY TO BE SUFFICIENTLY
MOIST TO SUPPORT SOME DZ. BUT AS THE SHRTWV NOW MOVING THRU NW MN
MOVES ENE INTO NW ONTARIO AND TAIL OF DEEP LYR QVECTOR CNVGC/DEEPER
MSTR ARRIVE W-E THIS AFTN...EXPECT SOME LIGHT SN TO PUSH INTO THE
AREA. BUT OVERALL DRYNESS OF THE MID LVLS SHOULD LIMIT THE INTENSITY
OF THIS PCPN. THE PCPN OVER THE SCENTRAL AND E MAY REMAIN IN THE
FORM OF FREEZING DZ/DZ/FLURRIES WELL INTO THE AFTN AS THE STRONGER
FORCING/DEEPER MOISTENING REMAIN TO THE W. HI TEMPS TODAY WL BE
ABOVE NORMAL AND IN THE 30S.
TNGT...AS THE SHRTWV IN ONTARIO CONTINUES TO THE NE AND AWAY FM UPR
MI...THE BULK OF THE DEEP LYR FORCING IS FCST TO LIFT TO THE NE. SO
AFTER A PERIOD OF LIKELY POPS MAINLY OVER THE W AND CENTRAL IN THE
EVNG...EXPECT DIMINISHING POPS OVERNGT. BULK OF THE SHORTER RANGE
MODELS INDICATE THE HEAVIER PCPN WL BE OVER THE CENTRAL CWA...WHERE
UPSLOPE SSE FLOW OFF LK MI WL COINCIDE WITH THE SHARPER DEEP LYR
QVECTOR DVGC. MAIN CONCERN REMAINS HOW MUCH DRY MID LVL DRY AIR IN
PLACE WL LIMIT PCPN TOTALS. BUT EXPECTED QPF UP TO 0.15 INCH IN THIS
AREA WL SUPPORT UP TO 2 INCHES OF SN. WITH OVC SKIES AND A STEADY S
WIND...THERE WL BE LTL DIURNAL DROP IN TEMP AND WELL ABV NORMAL LOWS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 434 AM EST SUN DEC 21 2014
COMPLICATED FORECAST STILL IN FULL SWING. DIFFERENCES ABOUND IN THE
MODELS...BOTH WITH THE INITIAL WEAKENING CLOSED LOW/SFC LOW DRIFTING
OUT OF THE NORTHERN PLAINS MONDAY AFTN THROUGH TUESDAY...THEN AGAIN
WITH SOUTHERN STREAM SFC LOW LIFTING NORTHWARD OVER THE GREAT LAKES
WEDNESDAY INTO CHRISTMAS DAY. SOME BREAKING NEWS THERE IN TERMS OF
MODEL TRENDS FOR SURE.
SHORTWAVE TROUGH WILL BE HEADING OVER THE NORTHERN PLAINS ON MONDAY
MORNING. SNOW THAT DEVELOPS LATER TODAY OVER UPPER LAKES WELL AHEAD
OF THIS SYSTEM DRIVEN BY LEAD SHORTWAVE/H85-H5 Q-VECTOR CONVERGENCE
AND H85-H7 MOISTURE TRANSPORT SHOULD BE IN PROCESS OF LIFTING OUT OF
UPR MICHIGAN ON MONDAY MORNING. SOUNDINGS SHOW RISK OF FZDZ IN WAKE
OF DEPARTING LGT SNOW ON MONDAY MORNING WITH DRY LAYER H85-H6 BUT
MOIST UPSLOPE SSE FLOW OFF LK MICHIGAN BLO H85. BY MONDAY AFTN OR
MON EVENING...SOUNDINGS MOISTEN MID-LEVELS IN RESPONSE TO SHORTWAVE
AND SFC LOW MOVING OVER THE NORTHERN PLAINS. SLOWER TREND SHOWS UP
IN THE LAST TWO RUNS OF THE ECMWF WITH THIS SYSTEM INTO TUESDAY AND
THAT PUTS THE ECMWF AT ODDS WITH THE GFS/NAM IDEAS WITH REGARD TO
SPEED OF SYSTEM AND LOCATION OF HEAVIER QPF. MAIN ISSUE IS GFS/NAM
SHOWING FARTHER NORTH H85-H7 LOW CENTER/DRY SLOT COMPARED TO FARTHER
SW ECMWF. GEM-REGIONAL SIMILAR TO ECMWF BUT NOT AS FAR NORTH WITH
HEAVIER QPF ON TUESDAY. USED A GENERAL CONSENSUS...BUT ULTIMATELY
WEIGHTED QPF INTO TUESDAY MORE TOWARD SLOWER/WETTER ECMWF/CANADIAN.
BASED ON 1000-850MB THICKNESS AND NAM SOUNDINGS...APPEARS THAT PTYPE
FOR AT LEAST TUESDAY MORNING SHOULD BE MAINLY SNOW JUST INLAND FM LK
MICHIGAN AND OVER REST OF CWA. BY AFTN THOUGH...NEAR SFC LAYER WARMS
ENOUGH TO RESULT IN MIX OF RAIN AND SNOW OVER MOST CWA...WITH MAINLY
RAIN EXPECTED OVER EAST HALF. A NARROW AND ELEVATED DGZ AROUND 600MB
WITH TEMPS WARMER THAN -10C BLO POINTS TO LOW SLR/S. EVEN SO...SEEMS
THAT INTERIOR SECTIONS OF CNTRL UPR MICHIGAN NEAR THE WI BORDER AND
MAYBE INTO THE INTERIOR SOUTH CNTRL...JUST INLAND FM KESC AND KMNM
COULD END UP WITH THE NEAR ADVY SNOW AMOUNTS MONDAY NIGHT INTO
TUESDAY MORNING. NEED 3 INCHES OF WET SLOPPY SNOW /SLR/S LESS THAN
20:1/ IN 12 HRS TO MEET ADVISORY CRITERIA. WILL BE SOMETHING TO
WATCH...BUT BASED ON CURRENT SPREAD OF SOLUTIONS...WILL PROBABLY
WILL NOT HAVE THIS PINNED DOWN UNTIL WITHIN 12-24 HR OF THE ARRIVAL
OF STEADIER SNOW.
EVENTUALLY AS TUESDAY WEARS ON REMNANT OF UPR/SFC LOWS SLIDE ACROSS
UPR MICHIGAN AND DRY SLOT WILL BECOME BIGGER FACTOR. ATTN BY LATE
TUESDAY INTO TUESDAY NIGHT WILL BE TO THE SOUTH AS STRONGER SHORTWAVE
IN SOUTHERN STREAM WILL BE POISED TO LIFT NORTH OVER THE TENNESSEE
AND OHIO VALLEYS. FOR BETTER OR WORSE...THIS PART OF THE FORECAST
HAS BECOME EVEN MORE MUDDLED THAN THE LAST COUPLE DAYS.
THE UPSHOT OF THE TRENDS FM THE 00Z GFS AND PARALLEL GFS/UKMET AND
ECMWF IS THAT THE STRONG SFC LOW THAT WAS FORECAST TO IMPACT THE
REGION IS NOT FORMING UNTIL IT IS WELL TO THE EAST OF HERE. THIS
ESSENTIALLY TURNS THIS SYSTEM INTO A NON-EVENT FOR THE UPPER GREAT
LAKES AS H85-H3 DPVA STAYS OVER LOWER LAKES AND PRIME SURGE OF STRONG
MOISTURE ADVECTION AND ASSOCIATED HEAVIER QPF ALSO STAYS MORE OVER
LOWER GREAT LAKES. NOT SAYING THAT IS EXACTLY WHAT WILL HAPPEN BUT IT
IS WHAT MAJORITY OF MODELS NOW SHOW. UPPER GREAT LAKES WOULD BE
AFFECTED BY A MOISTURE STARVED NORTHERN STREAM SHORTWAVE AND WEAK
TROUGH. NOT COLD AT ALL WITH H85 TEMPS AS THIS CROSSES LATE WEDNESDAY
INTO CHRISTMAS WARMER THAN -8C...SO IMPACT FM THAT SYSTEM WOULD BE
MINIMAL. OBVIOUSLY...THIS IS A FAR CRY FM BLOCKBUSTER STORM MODELS
HAD BEEN ADVERTISING AT LEAST FOR MAJORITY OF RUNS IN RECENT DAYS.
CURRENTLY THE ONLY MODEL THAT SHOWS THE STRONG STORM IS THE 00Z
CANADIAN WHICH HAS MAINTAINED CONTINUITY AS IT PEGS A 970MB LOW AT
00Z ON THURSDAY OVER NORTHERN LOWER MICHIGAN HEADING NORTH TOWARD
JAMES BAY ON THURSDAY. CONCERNED THAT TREND THAT GFS STARTED ON
SATURDAY HAS NOW BEEN LATCHED ON TO BY ECMWF WHICH HAD BEEN VERY
CONSISTENT UP TO THIS RUN. VERY STRIKING TO SEE THE NCEP FAVORED
UKMET SOLUTION CHANGE FROM A 968MB LOW OVER LK HURON AT 00Z THURSDAY
TO A 1004MB RIDGE WITH LATEST RUN VALID AT THE SAME TIME. WHOLE
FORECAST SITUATION IS HIGHLY CHANGEABLE...AND CANNOT RULE OUT THAT
MODELS WILL TREND BACK TO THE STRONG STORM. SHORTWAVE AND JET ENERGY
THAT ALL THIS EMERGES OUT OF IS JUST ENTERING PACIFIC NORTHWEST THIS
MORNING SO IT WILL NOW BE SAMPLED WELL FM HERE ON OUT. WE WILL SEE IF
THIS AFFECTS FOLLOWING MODEL SOLUTIONS. LIKELY IT WILL...BUT TO WHAT
DEGREE IS THE QUESTION.
GIVEN THE BIG CHANGES...LEANED HEAVILY ON CONSENSUS OF MODELS FOR
WEDNESDAY AND BEYOND. STILL APPEARS TO TURN COLDER BY NEXT WEEKEND
BEHIND THIS SYSTEM WITH DECENT SHOT OF LAKE EFFECT SNOW SHOWERS FOR
AREAS FAVORED BY NW WINDS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 708 AM EST SUN DEC 21 2014
AS AN INCRSG LLVL S WIND DRAWS MOISTER LLVL AIR INTO THE UPPER LKS
AND AN APRCHG DISTURBANCE CAUSES SN TO DEVELOP OVER THE AREA...
EXPECT CONDITIONS AT CMX AND SAW TO DETERIORATE TO IFR. SAW WL SEE
THE FASTER DETERIORATION AND STRONGER WINDS BECAUSE OF THE UPSLOPE
WIND COMPONENT AT THAT MORE EXPOSED SITE. SINCE THE S WIND PRESENTS
A DOWNSLOPE COMPONENT AT IWD AND EVEN THOUGH SOME IFR CONDITIONS MAY
BE OBSVD THERE FROM TIME TO TIME AFTER THE SN ARRIVES THIS AFTN...
SUSPECT PREDOMINANT CONDITIONS AT THAT LOCATION WL REMAIN MVFR.
AFTER THE EXIT OF THE HEAVIER SN LATE TNGT...CONDITIONS ARE LIKELY
TO IMPROVE TO LO END MVFR AT CMX AND SAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 434 AM EST SUN DEC 21 2014
S-SE WINDS INCREASE THIS AFTN AND SHOULD REMAIN UP TO 30 KTS OVER
MAINLY THE EAST HALF OF LK SUPERIOR TONIGHT THROUGH MONDAY AS A LOW
PRESSURE SYSTEM MOVES FM THE NORTHERN PLAINS TO THE WESTERN GREAT
LAKES. AS THE LOW LIFTS OVER THE AREA ON TUESDAY...WINDS WILL SETTLE
DOWN BLO 20 KTS. NEXT CHANCE FOR STRONGER WINDS DEVELOPS LATE
WEDNESDAY INTO THURSDAY AS LOW PRESSURE SYSTEM DEEPENS EAST OF LK
SUPERIOR. WNW-NW WINDS OF 30 KTS WITH A FEW GALE GUSTS TO 35 KTS
FAIRLY CERTAIN...BUT CONFIDENCE IN SYSTEM PRODUCING STRONGER GALES
ON THURSDAY IS NOT AS HIGH AS THE LAST COUPLE DAYS AS THE TREND IS
NOW FOR A WEAKER SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
437 AM EST SUN DEC 21 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 434 AM EST SUN DEC 21 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A RELATIVELY WEAK
W-E FLOW ALOFT EXTENDING FROM THE NRN PLAINS INTO THE NW GREAT LKS.
THERE IS EXTENSIVE LO CLD COVER OVER THE UPR MIDWEST/NW GREAT LKS
CONSISTENT WITH THE MOIST AIR LLVL AIR ADVECTED TO THE N BY THE S
WIND BTWN SFC HI PRES IN THE CNDN MARITIMES AND LOWER PRES IN THE
NRN PLAINS. LOCAL 00Z RAOBS SHOW THIS MSTR EXTENDS UP TO H85 TO AS
HI AS H7. ALTHOUGH THERE IS A WEAK SHRTWV PASSING OVER UPR MI EARLY
THIS MRNG...MID LVL DRYNESS SHOWN ON THE RAOBS ABOVE THE LOWER LVL
MSTR AND ABSENCE OF DYNAMIC FORCING HAS PREVENTED ANY PCPN. THERE IS
ANOTHER MORE VIGOROUS SHRTWV/SHARPER DPVA AND DEEP LYR QVECTOR CNVGC
MOVING INTO FAR NW MN...BUT RATHER DRY MID LVL AIR TO THE W AS WELL
IS LIMITING THE ACCOMPANYING PCPN TO SOME LIGHT SN OVER NCENTRAL MN.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON THE POTENTIAL FOR SOME
FREEZING DZ TODAY AS THE STEADY S LLVL FLOW ADVECTS SOMEWHAT HIER
DEWPTS INTO THE UPR LKS. FOCUS FOR LATER TDAY/TNGT SHIFTS TO THE CHC
FOR STEADY SN AS SHRTWV/QVECTOR CNVGC NOW IN NW MN DRIFTS TOWARD UPR
MI.
TODAY...MODELS SHOW H95-9 S WINDS INCRSG THRU THE DAY AND UP TO 30
KTS BY 00Z MON. AS THESE STRONGER WINDS TAP THE HIER NEAR SFC
SPECIFIC HUMIDITY...MOST OF THE MODELS GENERATE SOME SPOTTY LIGHT
PCPN OVER MAINLY THE SCENTRAL THIS MRNG INTO THE AFTN. SINCE THE
DEPTH OF THE LLVL MOIST LYR DOES NOT REACH THE DGZ...WL MAINTAIN THE
MENTION OF SOME FREEZING DZ OVER THE SCENTRAL WHERE THE LLVL SSE
FLOW UPSLOPES AND WHERE THE LLVLS ARE LIKELY TO BE SUFFICIENTLY
MOIST TO SUPPORT SOME DZ. BUT AS THE SHRTWV NOW MOVING THRU NW MN
MOVES ENE INTO NW ONTARIO AND TAIL OF DEEP LYR QVECTOR CNVGC/DEEPER
MSTR ARRIVE W-E THIS AFTN...EXPECT SOME LIGHT SN TO PUSH INTO THE
AREA. BUT OVERALL DRYNESS OF THE MID LVLS SHOULD LIMIT THE INTENSITY
OF THIS PCPN. THE PCPN OVER THE SCENTRAL AND E MAY REMAIN IN THE
FORM OF FREEZING DZ/DZ/FLURRIES WELL INTO THE AFTN AS THE STRONGER
FORCING/DEEPER MOISTENING REMAIN TO THE W. HI TEMPS TODAY WL BE
ABOVE NORMAL AND IN THE 30S.
TNGT...AS THE SHRTWV IN ONTARIO CONTINUES TO THE NE AND AWAY FM UPR
MI...THE BULK OF THE DEEP LYR FORCING IS FCST TO LIFT TO THE NE. SO
AFTER A PERIOD OF LIKELY POPS MAINLY OVER THE W AND CENTRAL IN THE
EVNG...EXPECT DIMINISHING POPS OVERNGT. BULK OF THE SHORTER RANGE
MODELS INDICATE THE HEAVIER PCPN WL BE OVER THE CENTRAL CWA...WHERE
UPSLOPE SSE FLOW OFF LK MI WL COINCIDE WITH THE SHARPER DEEP LYR
QVECTOR DVGC. MAIN CONCERN REMAINS HOW MUCH DRY MID LVL DRY AIR IN
PLACE WL LIMIT PCPN TOTALS. BUT EXPECTED QPF UP TO 0.15 INCH IN THIS
AREA WL SUPPORT UP TO 2 INCHES OF SN. WITH OVC SKIES AND A STEADY S
WIND...THERE WL BE LTL DIURNAL DROP IN TEMP AND WELL ABV NORMAL LOWS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 434 AM EST SUN DEC 21 2014
COMPLICATED FORECAST STILL IN FULL SWING. DIFFERENCES ABOUND IN THE
MODELS...BOTH WITH THE INITIAL WEAKENING CLOSED LOW/SFC LOW DRIFTING
OUT OF THE NORTHERN PLAINS MONDAY AFTN THROUGH TUESDAY...THEN AGAIN
WITH SOUTHERN STREAM SFC LOW LIFTING NORTHWARD OVER THE GREAT LAKES
WEDNESDAY INTO CHRISTMAS DAY. SOME BREAKING NEWS THERE IN TERMS OF
MODEL TRENDS FOR SURE.
SHORTWAVE TROUGH WILL BE HEADING OVER THE NORTHERN PLAINS ON MONDAY
MORNING. SNOW THAT DEVELOPS LATER TODAY OVER UPPER LAKES WELL AHEAD
OF THIS SYSTEM DRIVEN BY LEAD SHORTWAVE/H85-H5 Q-VECTOR CONVERGENCE
AND H85-H7 MOISTURE TRANSPORT SHOULD BE IN PROCESS OF LIFTING OUT OF
UPR MICHIGAN ON MONDAY MORNING. SOUNDINGS SHOW RISK OF FZDZ IN WAKE
OF DEPARTING LGT SNOW ON MONDAY MORNING WITH DRY LAYER H85-H6 BUT
MOIST UPSLOPE SSE FLOW OFF LK MICHIGAN BLO H85. BY MONDAY AFTN OR
MON EVENING...SOUNDINGS MOISTEN MID-LEVELS IN RESPONSE TO SHORTWAVE
AND SFC LOW MOVING OVER THE NORTHERN PLAINS. SLOWER TREND SHOWS UP
IN THE LAST TWO RUNS OF THE ECMWF WITH THIS SYSTEM INTO TUESDAY AND
THAT PUTS THE ECMWF AT ODDS WITH THE GFS/NAM IDEAS WITH REGARD TO
SPEED OF SYSTEM AND LOCATION OF HEAVIER QPF. MAIN ISSUE IS GFS/NAM
SHOWING FARTHER NORTH H85-H7 LOW CENTER/DRY SLOT COMPARED TO FARTHER
SW ECMWF. GEM-REGIONAL SIMILAR TO ECMWF BUT NOT AS FAR NORTH WITH
HEAVIER QPF ON TUESDAY. USED A GENERAL CONSENSUS...BUT ULTIMATELY
WEIGHTED QPF INTO TUESDAY MORE TOWARD SLOWER/WETTER ECMWF/CANADIAN.
BASED ON 1000-850MB THICKNESS AND NAM SOUNDINGS...APPEARS THAT PTYPE
FOR AT LEAST TUESDAY MORNING SHOULD BE MAINLY SNOW JUST INLAND FM LK
MICHIGAN AND OVER REST OF CWA. BY AFTN THOUGH...NEAR SFC LAYER WARMS
ENOUGH TO RESULT IN MIX OF RAIN AND SNOW OVER MOST CWA...WITH MAINLY
RAIN EXPECTED OVER EAST HALF. A NARROW AND ELEVATED DGZ AROUND 600MB
WITH TEMPS WARMER THAN -10C BLO POINTS TO LOW SLR/S. EVEN SO...SEEMS
THAT INTERIOR SECTIONS OF CNTRL UPR MICHIGAN NEAR THE WI BORDER AND
MAYBE INTO THE INTERIOR SOUTH CNTRL...JUST INLAND FM KESC AND KMNM
COULD END UP WITH THE NEAR ADVY SNOW AMOUNTS MONDAY NIGHT INTO
TUESDAY MORNING. NEED 3 INCHES OF WET SLOPPY SNOW /SLR/S LESS THAN
20:1/ IN 12 HRS TO MEET ADVISORY CRITERIA. WILL BE SOMETHING TO
WATCH...BUT BASED ON CURRENT SPREAD OF SOLUTIONS...WILL PROBABLY
WILL NOT HAVE THIS PINNED DOWN UNTIL WITHIN 12-24 HR OF THE ARRIVAL
OF STEADIER SNOW.
EVENTUALLY AS TUESDAY WEARS ON REMNANT OF UPR/SFC LOWS SLIDE ACROSS
UPR MICHIGAN AND DRY SLOT WILL BECOME BIGGER FACTOR. ATTN BY LATE
TUESDAY INTO TUESDAY NIGHT WILL BE TO THE SOUTH AS STRONGER SHORTWAVE
IN SOUTHERN STREAM WILL BE POISED TO LIFT NORTH OVER THE TENNESSEE
AND OHIO VALLEYS. FOR BETTER OR WORSE...THIS PART OF THE FORECAST
HAS BECOME EVEN MORE MUDDLED THAN THE LAST COUPLE DAYS.
THE UPSHOT OF THE TRENDS FM THE 00Z GFS AND PARALLEL GFS/UKMET AND
ECMWF IS THAT THE STRONG SFC LOW THAT WAS FORECAST TO IMPACT THE
REGION IS NOT FORMING UNTIL IT IS WELL TO THE EAST OF HERE. THIS
ESSENTIALLY TURNS THIS SYSTEM INTO A NON-EVENT FOR THE UPPER GREAT
LAKES AS H85-H3 DPVA STAYS OVER LOWER LAKES AND PRIME SURGE OF STRONG
MOISTURE ADVECTION AND ASSOCIATED HEAVIER QPF ALSO STAYS MORE OVER
LOWER GREAT LAKES. NOT SAYING THAT IS EXACTLY WHAT WILL HAPPEN BUT IT
IS WHAT MAJORITY OF MODELS NOW SHOW. UPPER GREAT LAKES WOULD BE
AFFECTED BY A MOISTURE STARVED NORTHERN STREAM SHORTWAVE AND WEAK
TROUGH. NOT COLD AT ALL WITH H85 TEMPS AS THIS CROSSES LATE WEDNESDAY
INTO CHRISTMAS WARMER THAN -8C...SO IMPACT FM THAT SYSTEM WOULD BE
MINIMAL. OBVIOUSLY...THIS IS A FAR CRY FM BLOCKBUSTER STORM MODELS
HAD BEEN ADVERTISING AT LEAST FOR MAJORITY OF RUNS IN RECENT DAYS.
CURRENTLY THE ONLY MODEL THAT SHOWS THE STRONG STORM IS THE 00Z
CANADIAN WHICH HAS MAINTAINED CONTINUITY AS IT PEGS A 970MB LOW AT
00Z ON THURSDAY OVER NORTHERN LOWER MICHIGAN HEADING NORTH TOWARD
JAMES BAY ON THURSDAY. CONCERNED THAT TREND THAT GFS STARTED ON
SATURDAY HAS NOW BEEN LATCHED ON TO BY ECMWF WHICH HAD BEEN VERY
CONSISTENT UP TO THIS RUN. VERY STRIKING TO SEE THE NCEP FAVORED
UKMET SOLUTION CHANGE FROM A 968MB LOW OVER LK HURON AT 00Z THURSDAY
TO A 1004MB RIDGE WITH LATEST RUN VALID AT THE SAME TIME. WHOLE
FORECAST SITUATION IS HIGHLY CHANGEABLE...AND CANNOT RULE OUT THAT
MODELS WILL TREND BACK TO THE STRONG STORM. SHORTWAVE AND JET ENERGY
THAT ALL THIS EMERGES OUT OF IS JUST ENTERING PACIFIC NORTHWEST THIS
MORNING SO IT WILL NOW BE SAMPLED WELL FM HERE ON OUT. WE WILL SEE IF
THIS AFFECTS FOLLOWING MODEL SOLUTIONS. LIKELY IT WILL...BUT TO WHAT
DEGREE IS THE QUESTION.
GIVEN THE BIG CHANGES...LEANED HEAVILY ON CONSENSUS OF MODELS FOR
WEDNESDAY AND BEYOND. STILL APPEARS TO TURN COLDER BY NEXT WEEKEND
BEHIND THIS SYSTEM WITH DECENT SHOT OF LAKE EFFECT SNOW SHOWERS FOR
AREAS FAVORED BY NW WINDS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1250 AM EST SUN DEC 21 2014
MVFR CEILINGS 1.5-2.5 KFT WILL SLOWLY LOWER TOWARD IFR CIGS LATE
SUNDAY AFTERNOON/EVENING AS S WINDS INCREASE AND BRING MORE MOISTURE
INTO THE AREA. EXPECT LIGHT SNOW TO DEVELOP AT ALL TAF SITES SUN
AFTERNOON WITH THE INCREASE IN MOISTURE IN THE AFTERNOON. VSBYS WILL
INITIALLY BE MVFR WITH THE ONSET OF SNOW BUT COULD LOWER TO IFR
TOWARD EVENING ESPECIALLY AT KCMX AND KSAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 434 AM EST SUN DEC 21 2014
S-SE WINDS INCREASE THIS AFTN AND SHOULD REMAIN UP TO 30 KTS OVER
MAINLY THE EAST HALF OF LK SUPERIOR TONIGHT THROUGH MONDAY AS A LOW
PRESSURE SYSTEM MOVES FM THE NORTHERN PLAINS TO THE WESTERN GREAT
LAKES. AS THE LOW LIFTS OVER THE AREA ON TUESDAY...WINDS WILL SETTLE
DOWN BLO 20 KTS. NEXT CHANCE FOR STRONGER WINDS DEVELOPS LATE
WEDNESDAY INTO THURSDAY AS LOW PRESSURE SYSTEM DEEPENS EAST OF LK
SUPERIOR. WNW-NW WINDS OF 30 KTS WITH A FEW GALE GUSTS TO 35 KTS
FAIRLY CERTAIN...BUT CONFIDENCE IN SYSTEM PRODUCING STRONGER GALES
ON THURSDAY IS NOT AS HIGH AS THE LAST COUPLE DAYS AS THE TREND IS
NOW FOR A WEAKER SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...VOSS
MARINE...JLA
AREA FORECAST DISCUSSION
NWS DULUTH MN
810 PM CST MON DEC 22 2014
.UPDATE...
ISSUED AT 810 PM CST MON DEC 22 2014
THE PRECIPITATION OVER MUCH OF NORTHLAND HAS DIMINISHED THIS
EVENING AS FORECAST BY MOST OF THE MODELS. THERE STILL REMAINS
AREAS OF LIGHT SNOW AND DRIZZLE...ESPECIALLY OVER OUR WESTERN
ZONES FROM THE BRAINERD LAKES NORTH TO INTERNATIONAL FALLS. HIGH
RES MODELS SUGGEST THIS WILL DECREASE AS WELL OVERNIGHT. THE
SURFACE LOW OVER WESTERN IOWA IS FORECAST TO LIFT TOWARD THE WI/IL
BORDER BY 12Z TUE. AN AREA OF PRECIP WAS MOVING N/NW TOWARD PRICE
COUNTY AND THAT SHOULD CONTINUE TO MOVE NORTH OVERNIGHT. THE
LATEST HRRR DOES WEAKEN THIS AS WELL OVERNIGHT BEFORE A LARGER
MORE INTENSE AREA OF SNOW MOVES IN TUESDAY MORNING. WE WILL NOT
CHANGE THE ADVISORY TIMING...BUT INSTEAD MENTIONED THE TIMING
ISSUES IN OUR VARIOUS PRODUCTS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 346 PM CST MON DEC 22 2014
MAIN FORECAST CONCERNS IN THE SHORT TERM REMAIN FOCUSED AROUND
THE POTENTIAL FOR ACCUMULATING SNOW OVER THE EASTERN HALF OF THE
FORECAST AREA TONIGHT THROUGH THE DAY TUESDAY. THE WINTRY MIX OF
DRIZZLE...RAIN AND SNOW THIS AFTERNOON AND EARLY EVENING WILL
CHANGE OVER TO ALL SNOW LATER TONIGHT. PATCHY FOG...LOCALLY
DENSE...WILL ALSO PERSIST THROUGH TUESDAY.
A WINTER WEATHER ADVISORY CONTINUES FOR PORTIONS OF NW WISCONSIN
FROM LATE THIS EVENING THROUGH LATE TUESDAY NIGHT.
LARGE UPPER LOW WILL ROTATE EWD FROM SE/NE THROUGH IA/SRN MN
TONIGHT AND INTO SRN WI/GREAT LAKES AREA ON TUESDAY. ON THE
LEADING NERN EDGE OF THIS SYSTEM A DRY WEDGE OF AIR IS EXPECTED TO
ROTATE INTO THE SYSTEM OVER LAKE SUPERIOR AND NRN MN TONIGHT. THIS
FEATURE WILL ALLOW MUCH OF THE PRECIP ACROSS NE MN TO CHANGE TO DZ
OR FZDZ...WHILE THE SFC LOW FILLS OUT AT THE BOTTOM OF THE
SYNOPTIC TROUGH AND BEGINS TO LIFT TO THE NE...SNOW AND DZ/RA WILL
PUSH IN FROM THE SOUTH.
AS THE LOW MOVES INTO ERN WI AROUND GREEN BAY A WELL DEFINED
DEFORMATION ZONE IS EXPECTED TO FORM ACROSS NRN WI INTO THE U.P.
AND LAKE SUPERIOR. SNOW WILL BECOME ENHANCED IN THIS AREA DURING
THE DAY TUESDAY. THE MOST FAVORABLE TIME FOR HEAVY SNOW WILL BE
FROM TUE MORNING INTO THE AFTERNOON FROM SHELL LAKE TO ASHLAND AND
AREAS TO THE EAST. HIGH SNOWFALL RATES WILL ALLOW A QUICK 2 TO 4
INCHES TO FALL IN A RELATIVELY SHORT PERIOD OF TIME. TOTAL
SNOWFALL AMTS WILL RANGE FROM 3 TO 5 INCHES ACROSS THE ADVISORY
AREA WITH LOCALLY HIGHER SNOWFALL TO 6 INCHES ALONG THE ELEVATED
REGIONS OF THE SOUTH SHORE. AREAS TO THE WEST ALONG THE I-35
AND HIGHWAY 61 CORRIDORS AND INTO THE TWIN PORTS WILL SEE
SNOWFALL AROUND 1 TO 3 INCHES.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 346 PM CST MON DEC 22 2014
FAIRLY ACTIVE WEATHER PATTERN WILL PERSIST INTO THIS WEEKEND.
WIDESPREAD LIGHT SNOW SHOULD BE WINDING DOWN WEDNESDAY NIGHT AT THE
BEGINNING OF THE EXTENDED PERIODS. LAKE EFFECTS WILL PROVIDE SOME
ENHANCEMENT ALONG THE SOUTH SHORE OF LK SUPERIOR..BUT LACK OF TRUE
ARCTIC AIR SHOULD ACT TO LIMIT OVERALL AMOUNTS.
STRONG SURFACE LOW WILL DEVELOP OVER THE TENNESSEE VALLEY REGION
WEDNESDAY AND MOVE TOWARD LAKE HURON BY THURSDAY MORNING..BUT THIS
LOW IS EXPECTED TO REMAIN SUFFICIENTLY FAR EAST WHERE SENSIBLE
WEATHER EFFECTS ON THE DULUTH CWA WILL BE MINIMAL..IF ANY.
A VERY WEAK DISTURBANCE WILL BRUSH BY NORTHERN MINNESOTA WEDNESDAY
NIGHT/THURSDAY..WHICH MAY BRING A BIT OF LIGHT SNOW ACROSS THE VERY
FAR NORTH. OVERALL HOWEVER..THIS IS REALLY NOT EXPECTED TO BE A BIG
DEAL.
THE BIGGEST POTENTIAL WEATHER SYSTEM DURING THE EXTENDED PERIOD
APPEARS TO BE THE RAPIDLY MOVING S/W TROF THAT IS PROGGED TO MOVE
FROM ERN COLORADO TO THE U.P. OF MICHIGAN FROM LATE THURSDAY NIGHT
THROUGH FRIDAY EVENING. THE FAST MOVEMENT WILL ACT TO LIMIT THE
DURATION OF MODERATE TO STRONG FORCING FOR ASCENT..BUT THERE APPEARS
TO BE SOME SUPPORT FOR THE IDEA OF FRONTOGENESIS ENHANCEMENT
DEPICTED IN THE MEDIUM RANGE MODELS. GIVEN THE CHANGES THAT WERE
OBSERVED IN THE MODEL EVOLUTION FOR THE PREVIOUS TWO SIGNIFICANT
SYSTEMS..CONFIDENCE IS SOMEWHAT LESS THAN NORMAL. DETAILS WILL NEED
TO BE RESOLVED AS THE SYSTEM GETS CLOSER DURING THIS WEEK. WITH THAT
SAID..WITH THE AVAILABLE DATA RIGHT NOW..THIS APPEARS TO HAVE
POTENTIAL FOR A HIGH-END ADVISORY OR LOW-END WARNING TYPE EVENT FOR
SOMEWHERE IN..OR CLOSE TO THE DULUTH CWA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 555 PM CST MON DEC 22 2014
THE NORTHLAND WILL CONTINUE TO BE IMPACTED BY AN AREA OF LOW
PRESSURE. PLENTY OF MOISTURE COVERED THE REGION AS WELL AND THAT WILL
RESULT IN IFR OR LIFR CONDITIONS THROUGH MUCH OF THE PERIOD.
PERIODS OF SNOW/DRIZZLE AND AS TEMPERATURES SLOWLY COOL...FREEZING
DRIZZLE...WILL CONTINUE THROUGH THE EVENING. MUCH OF THE MODEL
GUIDANCE SUGGEST MUCH OF THE PRECIPITATION OVER NORTHEAST
MINNESOTA WILL DIMINISH TONIGHT. HOWEVER...AS THE LOW LIFTS NORTH
LATER TONIGHT...MORE PRECIPITATION WILL SURGE NORTH TOWARD
NORTHERN WISCONSIN. FORECAST SOUNDINGS SUPPORT MAINLY SNOW ONCE
THIS STARTS LATER TONIGHT.
THE SNOW WILL THEN PUSH WEST AND FURTHER NORTH THROUGH THE DAY
TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 33 33 28 31 / 70 60 60 10
INL 32 33 27 31 / 80 30 30 20
BRD 32 33 29 32 / 80 60 50 10
HYR 33 34 30 32 / 80 90 60 20
ASX 33 34 31 32 / 80 100 60 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR WIZ002>004-
008-009.
LS...SMALL CRAFT ADVISORY FROM 4 AM TUESDAY TO 4 AM CST WEDNESDAY FOR
LSZ121-142>148.
&&
$$
UPDATE...MELDE
SHORT TERM...BJT
LONG TERM...MILLER
AVIATION...MELDE
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1120 PM CST Sat Dec 20 2014
.UPDATE:
Issued at 924 PM CST Sat Dec 20 2014
Clouds are lingering over the entire CWA this evening and will
likely do so into the overnight hours as we are experiencing one
of the longest nights of the year. Latest satellite observations
has shown that low clouds are expanding slowly eastward over
east central/southeast Illinois while there has been very little
movement over southeast Missouri. Latest ACARS sounding from KSTL
shows a decent inversion between 900-850mb with plenty of moisture
below it, and the RAP keeps plenty of low level moisture over the
CWA tonight, so left cloudy skies over the CWA the rest of the
night. Also raised temperatures tonight, particularly in the
southern and eastern counties where clearing was previously
forecast.
Britt
&&
.SHORT TERM: (Through Late Tonight)
Issued at 302 PM CST Sat Dec 20 2014
Clouds will persist early tonight and perhaps start to decrease
from south to north by morning. Overnight lows should be similar
to last night in most locations.
Kanofsky
.LONG TERM: (Sunday through Next Saturday)
Issued at 302 PM CST Sat Dec 20 2014
The primary forecast issues revolve around a large low pressure
system and a deep trough which are expected to affect the area
between Mon and Wed.
The ongoing gradual warming trend (highs today were generally about
5 degrees warmer than yesterday, which in turn was a few degrees
warmer than the previous day) will persist on Sunday and Monday.
Monday`s highs in the mid-40s to lower 50s will be around 10
degrees above average for this time of year.
The aforementioned low pressure system develops over the northern
plains on Sunday and Sunday night, eventually closing off on Mon or
Mon night within a deep trough over the central CONUS. This system
will dominate our weather through Wed, and widespread rain is likely
as it moves into the region on Mon and Mon night. Forecast PW values
of between 0.6" and 0.8" by 00z Tue are above the 75th percentile
and approaching +2 SD for December. A cold front is expected to move
through parts of MO/IL on late Mon night or Tue morning, which is
slower timing than the models were predicting yesterday. By Tue
afternoon or evening, some of the rain will probably switch over
to light snow within the colder post-frontal air mass.
Temperatures return to near or below average behind the front.
Meanwhile, a second vort max is forecast to drop into the central
CONUS trough and induce a new surface wave along the cold front
somewhere in TX/AR/LA (a third, smaller vort max interacts with
the northern upper low center during this time). The resulting
southern system then lifts northeastward on Tue and Tue night, but
there are sufficient differences between the GFS and ECMWF to
preclude getting more specific than SChc/Chc PoPs with a generic
rain/snow mix.
After the trough rotates away on Wed night or Thu, a brief period
of upper ridging is anticipated ahead of the next disturbance. The
12z runs of the ECMWF and GFS are in better agreement on the large
scale pattern compared to 24hrs ago, but the forecast with this
system will still depend on what will have happened with the
previous system, and confidence remains low.
Kanofsky
&&
.AVIATION: (For the 06z TAFs through 06z Sunday Night)
Issued at 1117 PM CST Sat Dec 20 2014
Focus will continue to be cigs thru the period. Guidance continues
to handle the current trends poorly across the region. Have
therefore continued low confidence in cig heights, but believe
overall trends are reflected in TAFs. Believe conditions will
remain largely as-is except UIN becoming MVFR in the next hour or so.
Cigs shud slowly lift Sun around Noon or during the afternoon.
Specifics for KSTL: Expect cigs to remain in higher MVFR range
thru much of the forecast period with sely to ssely winds aob 10
kts. Believe cigs will lift to VFR Sun afternoon, however, exact
timing remains uncertain.
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
719 PM MST MON DEC 22 2014
.UPDATE...
LATEST MESOANALYSIS CONTINUES TO SHOW MID LEVEL LAPSE RATES OF
7.5 C/KM ACROSS OUR CENTRAL PARTS. THIS ALONG WITH WEAK SHORTWAVE
ENERGY IN THE NORTHERLY FLOW IS ALLOWING FOR SNOW SHOWERS TO
CONTINUE DEVELOP ALONG UPSLOPE AREAS OF THE BEARTOOTH ABSAROKAS.
NOT EXPECTING MUCH ACCUMULATION BUT HAVE RAISED POPS AND SNOW AMTS
A BIT AT SUCH PLACES AS NYE AND RED LODGE. FURTHER EAST...TROWAL
CONTINUE TO WRAP LIGHT PCPN INTO FALLON AND CARTER COUNTIES. WINDS
HAVE STARTED TO DECREASE BUT LATEST BHK OB SHOWS A VSBY OF 2SM.
GIVEN COLDER CLOUD TOPS DROPPING OUT OF NORTHEAST MT WILL MAKE NO
CHANGES TO THE WINTER WX ADVYS WHICH ARE IN EFFECT FOR OUR FAR
EASTERN ZONES THRU 12Z. WOULD EXPECT THIS AREA OF PCPN TO TAPER
OFF LATE TONIGHT. ELSEWHERE IT WILL BE A REASONABLY QUIET WX NIGHT
WITH GRADUALLY DECREASING WINDS. JKL
&&
.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 GOOD
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...
LOWER CEILINGS AND LIGHT SNOWS WILL CONTINUE ACROSS FAR SOUTHEAST
MONTANA OVERNIGHT WITH MVFR CONDITIONS. THE LOWER CEILINGS WILL
EXTEND AS FAR NORTHWEST AS KMLS TO KSHR. ELSEWHERE...VFR
CONDITIONS WILL PREVAIL WITH SCATTERED TO BROKEN MID LEVEL CLOUDS.
FRIEDERS
&&
.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
72/S 11/B 47/J 42/J 11/B 13/J 32/J
BHK 021/029 015/038 024/025 008/019 007/025 009/021 003/013
+2/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 BILLINGS MT
350 PM MST SUN DEC 21 2014
.SHORT TERM...VALID FOR MON AND TUE...
DYNAMIC SHORTWAVE IN NW FLOW ALOFT CURRENTLY PUSHING THROUGH
SOUTHEAST MT. STRONG WINDS HAVE BEEN OCCURRING FOR SEVERAL HOURS
IN HARLOWTON AND JUST RECENTLY WE HAVE SEEN GUSTS TO 58-59 MPH
SURFACE AT BILLINGS AND COLUMBUS...WITH SOME ASSISTANCE FROM THE
LIGHT SHOWER ACTIVITY AROUND THE AREA. PEAK GUSTS COINCIDE PRETTY
WELL WITH RAP 800MB WINDS...AND AS TEMPS HAVE REACHED THE LOW 50S
THE BOUNDARY LAYER IS WELL-MIXED. RAP/GFS SHOW 800MB FLOW
INCREASING TO 55 KTS OVER THE NEXT FEW HOURS FROM BILLINGS TO
SHERIDAN...IN PATH OF VORT MAX AS SEEN ON WATER VAPOR IMAGERY.
GIVEN THE INGREDIENTS AND AN EXPECTATION OF A FEW HOURS OF STRONG
W-NW WINDS HAVE ISSUED A HIGH WIND WARNING THRU MIDNIGHT TO
INCLUDE COLUMBUS...BILLINGS...HARDIN...LODGE GRASS AND SHERIDAN.
ELSEWHERE WILL MAKE NO CHANGES TO WIND HIGHLIGHTS THOUGH WOULD
EXPECT A DECREASE LATER TONIGHT IN THESE AREAS AS WELL.
LIVINGSTON...BIG TIMBER AND NYE HAVE STAYED BELOW ADVISORY
CRITERIA FOR MUCH OF THE DAY BUT WITH STRONGER GUSTS NEARBY WILL
LET THE HIGHLIGHT RIDE A BIT LONGER.
HEAVIEST SNOW HAS ENDED OVER OUR SW MTNS AS MOISTURE PLUME HAS
BEEN PUSHED W-S OF OUR AREA...BUT UNSTABLE NW FLOW IS CONTINUING
TO PRODUCE SNOW SHOWERS WHICH ARE PROBABLY LOCALLY HEAVY. IN
ADDITION...THERE IS A SHORT-LIVED BULGE OF ISENTROPIC ASCENT
LATER TONIGHT INTO MONDAY MORNING AHEAD OF ANOTHER PIECE OF
ENERGY...AND THIS SHOULD ENHANCE THE SNOW SHOWERS ESPECIALLY FOR
NW ASPECTS. WILL LET THE WINTER STORM WARNING RIDE FOR THE
BEARTOOTH ABSAROKAS THRU NOON TOMORROW.
NEXT AREA OF CONCERN IS OUR FAR EAST AS TROWAL WRAPS SOUTHWARD
ACROSS FAR SOUTHEAST MT TOMORROW ON BACK SIDE OF UPPER LOW IN THE
DAKOTAS. LOOKS LIKE A 1-3 INCH SNOWFALL WHICH COMBINED WITH NW
WIND GUSTS OF 35-45 MPH WILL CAUSE SOME BLOWING SNOW AND POOR
TRAVEL CONDITIONS. HAVE ISSUED A WINTER WX ADVISORY TO COVER THIS
FOR FALLON AND CARTER COUNTIES. IMPACTS WILL ALSO BE FELT FURTHER
WEST TOWARD MILES CITY...BROADUS...LAME DEER AND SHERIDAN THOUGH
CURRENT INDICATIONS ARE THAT GREATEST SNOW ACCUMS WILL BE CLOSER
TO THE DAKOTAS BORDER. WIND GUSTS SHOULD EXCEED 50 MPH IN SHERIDAN
TOMORROW...WITH ENHANCEMENT ALONG THE EAST SLOPES OF THE BIGHORN
MOUNTAINS. PCPN IN OUR EAST SHOULD TAPER OFF BY EARLY TUESDAY AS
HEIGHTS BEGIN TO RISE FROM THE WEST.
PERIOD OF DRY WEATHER IS IN STORE TUESDAY AND TUESDAY NIGHT AS
RIDGE BUILDS IN FROM THE WEST. BACKED FLOW ALOFT ALONG WITH LEE
SIDE TROFFING AND COLD AIR IN THE PARK WILL BRING OUR NEXT PERIOD
OF STRONG SW WINDS FOR THE USUAL GAP AREAS.
TEMPS WILL TAKE A STEP DOWN THE NEXT TWO DAYS BUT WILL REMAIN A
LITTLE ABOVE NORMAL WITH HIGHS MOSTLY IN THE 30S TO LOWER 40S.
COOLEST TEMPS WILL BE FELT NEAR THE DAKOTAS BORDER.
JKL
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
CONSISTENCY IN THE MODELS IS NOT OPTIMAL BUT STILL STRONG ENOUGH
TO START SUPPORTING A DEPICTION OF HOW THE WEATHER WILL UNFOLD
THROUGH THE CHRISTMAS HOLIDAY. WEDNESDAY WILL BE VERY WINDY ACROSS
A LARGE PORTION OF THE REGION AND MILD. WEDNESDAY NIGHT A COLD
FRONT MOVES INTO AFTER THE EVENING HOURS...SOMETIMES BETWEEN 10 PM
AND 4 AM. THIS BRINGS A SHIFT TO MUCH COLDER TEMPERATURES AND
SNOWFALL. THIS SOLUTION IS SUPPORTED BY A BLEND OF LATEST WRF AND
ECMWF AND GFS IS THE OUTLIER. FRONT IS FAST MOVING WITH SHORT
LIVED SNOWFALL CHANCES BUT UPPER LEVEL SUPPORT MOVES OVER THE
FRONTAL ZONE WHICH COULD ALLOW FOR A 2 TO 3 INCH SNOWFALL IN 8
HOURS.
HAVE DRIED OUT WEDNESDAY DAY FORECAST A LITTLE BUT KEPT SNOWFALL
CHANCES FOR WEDNESDAY NIGHT AND CHRISTMAS DAY. FRIDAY IS A QUIETER
DAY WITH COOL NORTHWEST FLOW BUT IT IS MOSTLY DRIER WITH A CHANCE
OF MOUNTAIN SNOW. SATURDAY LOOKS RELATIVELY QUIET TOO BUT AN
ADDITIONAL ROUND OF GAP FLOW WINDS COULD BE SETTING UP LATER ON
SATURDAY NIGHT.
MODELS PICKING UP ON A STRONGER ARCTIC INTRUSION NEXT WEEKEND BUT
NOT CONFIDENT IF ITS SUNDAY OR MONDAY. THIS LOOKS LIKE A MUCH
STRONGER PATTERN CHANGE THAN THE WEDNESDAY NIGHT SYSTEM. BORSUM
&&
.AVIATION...
VERY WINDY CONDITIONS SHOULD BE EXPECTED THIS EVENING FOR A KBIL
TO KSHR LINE AND AREAS WEST WITH WIND GUSTS TO 50KT POSSIBLE WITH
SUSTAINED WINDS OF 35 KT. WINDS WILL DECREASE AFTER MIDNIGHT BUT
REMAIN STRONG ESPECIALLY ALONG THE FOOTHILLS. WINDS WILL AGAIN
INCREASE IN STRENGTH AFTER DAYBREAK ON MONDAY.
MOUNTAIN AREAS WILL CONTINUE TO SEE PERIODS OF HEAVY SNOW SHOWERS
WITH SIGNIFICANT OBSCURATIONS. OTHERWISE LOWER ELEVATIONS CAN
EXPECT BRIEF MVFR CONDITIONS WITH THE HEAVIER SHOWERS THIS
EVENING. BORSUM.
&&
.PRELIMINARY POINT TEMP/POPS...
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 034/041 025/039 026/041 029/034 015/030 014/031 015/029
22/W 20/N 02/W 66/S 31/B 11/B 22/S
LVM 031/037 016/034 023/041 028/036 012/029 012/032 018/032
44/J 20/N 03/W 77/S 41/B 12/S 22/S
HDN 031/040 022/037 019/040 025/033 011/029 010/030 010/028
33/J 30/B 02/W 66/S 31/B 11/B 22/S
MLS 029/034 022/035 020/040 025/031 013/027 014/029 009/026
47/J 31/B 13/W 43/S 21/E 12/S 22/S
4BQ 031/034 024/034 017/042 026/035 013/028 012/030 010/028
47/J 62/J 11/E 45/S 21/E 11/B 22/S
BHK 027/030 021/030 015/039 022/030 010/023 012/025 007/022
78/J 62/J 12/W 33/S 21/B 12/S 22/S
SHR 030/037 022/035 018/042 025/033 012/030 011/034 013/030
44/W 41/B 02/W 66/S 31/B 11/B 22/S
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...HIGH WIND WARNING IN EFFECT UNTIL NOON MST MONDAY FOR ZONES
28-42-63.
WINTER WEATHER ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 5
AM MST TUESDAY FOR ZONES 33-37.
HIGH WIND WARNING IN EFFECT UNTIL MIDNIGHT MST TONIGHT FOR
ZONES 34-35-38-57.
WIND ADVISORY IN EFFECT UNTIL NOON MST MONDAY FOR ZONES
41-65-66.
WINTER STORM WARNING IN EFFECT UNTIL NOON MST MONDAY FOR ZONE
67.
WY...HIGH WIND WARNING IN EFFECT UNTIL MIDNIGHT MST TONIGHT FOR
ZONE 99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1055 AM MST Sun Dec 21 2014
...UPDATE TO AVIATION...
.UPDATE...
MDOT highway cams reveal snow falling over area mountain passes
with reduced visibility as forecast. This snow will continue
through the day. Light freezing rain has been reported in Ft.
Belknap southeast of Havre. Light rain showers over this area
continue to move east with temperatures rising above freezing, so
expect this hazard to end by 11am. Wind gusts along the Rocky
Mountain Front are just now exceeding 60mph. Surface pressure is
beginning to rise along a line from Cut Bank to Great Falls to
Helena. Expect wind gusts to increase with these pressure rises
along the Rocky Mountain Front, then expand eastward into Central
Montana through the afternoon. HRRR guidance for wind gusts
supports strengthening wind gusts today. High wind warnings and
winter weather advisories for mountain snowfall remain in effect.
Updated temperatures and winds forecast for today to align closer
with observed trends. Nutter
&&
.AVIATION...
UPDATED 1755Z.
A strong and unsettled northwesterly flow aloft is propelling a
surface cold front through central Montana at this hour. Isolated to
scattered rain and freezing rain showers ahead of the front will
move into eastern Montana by 20Z. Behind the front, gusty winds and
isolated showers will continue over the plains and in the valleys
through 00Z Monday. However, the western and southwest mountains
will continue to see widespread snow, blowing snow and obscurations
through the period. Strong winds aloft will continue to fuel
mountain wave turbulence to the lee of north-south oriented mountain
ranges as well as low level wind shear. Eastern slopes of the
Rockies can anticipate local wind gusts in excess of 70 mph at times
through this afternoon. mpj
&&
.PREV DISCUSSION...
/ISSUED 438 AM MST Sun Dec 21 2014/
Today through Tuesday...Strong west to northwest flow aloft today. A
shortwave will move through this flow and keep winds very strong.
Radar shows light precip over the western mountains. This
precipitation will spread east this morning as a low pressure
shortwave and associated cold front cross the Rockies. A surface low
pressure trof is over the CWA with higher pressure over Western. The
NAM gives 40 kt winds at just above the boundary level through the
day. Due to the position of the jet and timing of the front, will
cancel the current high wind watch but issue a warning for Lewis and
Clark, Cascade, Chouteau, Judith Basin, and Fergus counties. The
period of strongest winds will be associated with the frontal
passage. Will start Lewis and Clark warning with the issuance of
this forecast package, and start the others at 18z. The jet over the
Rockies will gradually shift to a more northwest direction during
the night. A ridge will build over the Eastern Pacific and northwest
flow aloft will be over the zones Monday. This ridge will be over
the Pacific Northwest by early Tuesday morning and move over the
zones during the day. The airmass will remain dry underneath the
high pressure but also remain rather cool. Zelzer
Tuesday night through Sunday...Expect another Pacific storm system
to move through the region from Tuesday night through Christmas Day.
Precipitation will be light to start with Tuesday night into
Wednesday morning...but will pick up in intensity by late Wednesday
afternoon through Christmas morning. It still looks like the swath
of heaviest snowfall will fall west of a line from Cut Bank to
Lewistown...with the Havre area only seeing around an inch of snow.
Otherwise...overall total snow accumulations still look to be on
track from previous forecasts...with a slight increase in the
mountains. Thus a generally 2 to 5 inches is expected at lower
elevations and 6 to 12 inches is expected in the mountains. Isolated
amounts around 16 inches will be possible in the mountains.
Temperatures will be mild Wednesday morning...but will fall rather
quickly Wednesday afternoon as colder air moves into the region
changing any rain back over to snow. For Friday and Saturday...it
will generally be cold with just a passing snow shower from time to
time. For Sunday and into early next week...the GFS13 and EC are
quite different. The EC model wants to start slowly warming things
up with little precipitation...while the GFS13 wants to bring down
significantly colder air and a better chance for precipitation. For
now I will go in the middle...but changes in the forecast are likely
to occur for this time period once model agreement starts to become
a bit more clear. Brusda
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 47 30 39 20 / 40 20 20 20
CTB 43 27 37 20 / 30 20 10 10
HLN 45 29 37 16 / 80 30 30 20
BZN 42 24 33 8 / 70 40 40 20
WEY 38 21 31 4 / 100 80 50 30
DLN 44 28 35 12 / 80 50 30 10
HVR 44 28 40 20 / 90 40 30 20
LWT 47 29 37 19 / 80 40 30 30
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING until 5 PM MST this afternoon Central and
Southern Lewis and Clark...Northern Rocky Mountain Front...
Southern Rocky Mountain Front.
WINTER WEATHER ADVISORY until 5 AM MST Monday FOR ELEVATIONS
ABOVE 5000 FEET FOR Central and Southern Lewis and Clark...
Jefferson...Northern Rocky Mountain Front...Southern Rocky
Mountain Front.
WINTER WEATHER ADVISORY until 5 AM MST Monday FOR ELEVATIONS
ABOVE 5500 FEET FOR Beaverhead...Broadwater...Cascade...
Gallatin...Judith Basin...Madison...Meagher.
HIGH WIND WARNING until 10 PM MST this evening Cascade...
Chouteau...Fergus...Judith Basin.
&&
$$
weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
956 AM MST Sun Dec 21 2014
.UPDATE...
MDOT highway cams reveal snow falling over area mountain passes
with reduced visibility as forecast. This snow will continue
through the day. Light freezing rain has been reported in Ft.
Belknap southeast of Havre. Light rain showers over this area
continue to move east with temperatures rising above freezing, so
expect this hazard to end by 11am. Wind gusts along the Rocky
Mountain Front are just now exceeding 60mph. Surface pressure is
beginning to rise along a line from Cut Bank to Great Falls to
Helena. Expect wind gusts to increase with these pressure rises
along the Rocky Mountain Front, then expand eastward into Central
Montana through the afternoon. HRRR guidance for wind gusts
supports strengthening wind gusts today. High wind warnings and
winter weather advisories for mountain snowfall remain in effect.
Updated temperatures and winds forecast for today to align closer
with observed trends. Nutter
&&
.AVIATION...
UPDATED 1138Z.
An upper level low pressure disturbance will bring increased cloud
cover and precipitation across Central and Southwest Montana through
tonight. Best chances for snow will be over the Rockies and
mountains of Southwest Montana. Local IFR/MVFR conditions will
continue through Monday along with areas of mountain obscuration.
Strong winds aloft will continue through today with 50kt winds
expected at ridge tops and mountain wave turbulence is likely. These
strong winds will also cause strong gusts at the surface today and
this evening.
&&
.PREV DISCUSSION...
/ISSUED 438 AM MST Sun Dec 21 2014/
Today through Tuesday...Strong west to northwest flow aloft today. A
shortwave will move through this flow and keep winds very strong.
Radar shows light precip over the western mountains. This
precipitation will spread east this morning as a low pressure
shortwave and associated cold front cross the Rockies. A surface low
pressure trof is over the CWA with higher pressure over Western. The
NAM gives 40 kt winds at just above the boundary level through the
day. Due to the position of the jet and timing of the front, will
cancel the current high wind watch but issue a warning for Lewis and
Clark, Cascade, Chouteau, Judith Basin, and Fergus counties. The
period of strongest winds will be associated with the frontal
passage. Will start Lewis and Clark warning with the issuance of
this forecast package, and start the others at 18z. The jet over the
Rockies will gradually shift to a more northwest direction during
the night. A ridge will build over the Eastern Pacific and northwest
flow aloft will be over the zones Monday. This ridge will be over
the Pacific Northwest by early Tuesday morning and move over the
zones during the day. The airmass will remain dry underneath the
high pressure but also remain rather cool. Zelzer
Tuesday night through Sunday...Expect another Pacific storm system
to move through the region from Tuesday night through Christmas Day.
Precipitation will be light to start with Tuesday night into
Wednesday morning...but will pick up in intensity by late Wednesday
afternoon through Christmas morning. It still looks like the swath
of heaviest snowfall will fall west of a line from Cut Bank to
Lewistown...with the Havre area only seeing around an inch of snow.
Otherwise...overall total snow accumulations still look to be on
track from previous forecasts...with a slight increase in the
mountains. Thus a generally 2 to 5 inches is expected at lower
elevations and 6 to 12 inches is expected in the mountains. Isolated
amounts around 16 inches will be possible in the mountains.
Temperatures will be mild Wednesday morning...but will fall rather
quickly Wednesday afternoon as colder air moves into the region
changing any rain back over to snow. For Friday and Saturday...it
will generally be cold with just a passing snow shower from time to
time. For Sunday and into early next week...the GFS13 and EC are
quite different. The EC model wants to start slowly warming things
up with little precipitation...while the GFS13 wants to bring down
significantly colder air and a better chance for precipitation. For
now I will go in the middle...but changes in the forecast are likely
to occur for this time period once model agreement starts to become
a bit more clear. Brusda
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 47 30 39 20 / 40 20 20 20
CTB 43 27 37 20 / 30 20 10 10
HLN 45 29 37 16 / 80 30 30 20
BZN 42 24 33 8 / 70 40 40 20
WEY 38 21 31 4 / 100 80 50 30
DLN 44 28 35 12 / 80 50 30 10
HVR 44 28 40 20 / 90 40 30 20
LWT 47 29 37 19 / 80 40 30 30
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING until 5 PM MST this afternoon Central and
Southern Lewis and Clark...Northern Rocky Mountain Front...
Southern Rocky Mountain Front.
WINTER WEATHER ADVISORY until 5 AM MST Monday FOR ELEVATIONS
ABOVE 5000 FEET FOR Central and Southern Lewis and Clark...
Jefferson...Northern Rocky Mountain Front...Southern Rocky
Mountain Front.
WINTER WEATHER ADVISORY until 5 AM MST Monday FOR ELEVATIONS
ABOVE 5500 FEET FOR Beaverhead...Broadwater...Cascade...
Gallatin...Judith Basin...Madison...Meagher.
HIGH WIND WARNING until 10 PM MST this evening Cascade...
Chouteau...Fergus...Judith Basin.
&&
$$
weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
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AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1035 PM MST Sat Dec 20 2014
Updated Aviation Discussion
.DISCUSSION...
Update forthcoming. Have lowered temperatures a tad in areas where
advancing clouds have yet to arrive. With clouds overspreading the
area from the west overnight, temperatures will not drop too far.
High wind highlights will remain in place, though wind speeds are
currently below warning criteria along the Rocky Mountain Front.
Latest RUC analysis indicates westerly winds aloft will strengthen
considerably after 10z. Winter Weather Advisory highlights will also
continue. Snow has begun over the Rocky Mountain Front and over
portions of southwest Montana. Snow not expected to begin over the
Central mountains until after midnight, closer to daybreak.
&&
.AVIATION...
UPDATED 0535Z.
A strengthening and increasingly moist West/Northwest flow aloft
will move across the Northern Rockies and MT tonight through Sunday.
This will spread increasing cloudiness across the region tonight
with precipitation and terrain obscurations spreading east over the
mountains tonight and continuing through Sunday. Precipitation will
spread into the KBZN terminal vicinity after 08z with occasional
MVFR in lower CIGS/-SN late tonight through Sunday morning before
conditions improve some Sunday afternoon. Precipitation will be less
widespread at lower elevations of Central/N-Central MT and snow
levels will be around 4000-5000 ft MSL. W-NW winds aloft increase to
around 50kts at ridgetops by Sunday morning with Mtn wave turbulence
likely east of the Rockies and gusty surface winds likely at most
terminals by Sunday afternoon. Hoenisch
&&
.PREV DISCUSSION...Issued 303 PM MST Sat Dec 20 2014
Tonight through Monday...A plume of moisture is pushing through
the Pacific Northwest on a strong westerly jetstream. Ridging
further west will turn the upper level flow northwesterly,
positioning western and southwest Montana beneath the jet exit
region. A shortwave trough will move through this flow from
British Columbia to eastern Montana, causing a lee surface trough
to develop. The overall result is heavy mountain snow, areas of
light rain at low elevations, and strong winds across central
Montana. Little, if any precipitation is expected for western
portion of the central plains. Areas of light freezing rain are
possible tonight generally north and east of the Bears Paw
mountains as warmer air spreads over a colder airmass in northeast
Montana.
Wind gusts will strengthen along the Rocky Mountain Front early
Sunday where a high wind warning remains in effect. Strong wind
gusts will extend further east onto the adjacent plains, but the
high wind watch continues with lowered confidence that winds here
will reach warning criteria. Winter weather advisories now cover
the Rocky Mountains above 5000 feet and for the Central and
Southwest mountains above 5500 feet. Travelers through mountain
passes on Sunday should expect snow covered and icy roads. Snow
will be later to start in the Little Belt and other central
Montana ranges...and will likely continue later into Monday. Nutter
Monday night through Saturday...Shortwave ridge develops over the
region Monday night into Tuesday afternoon with dry conditions at
lower levels but scattered to numerous showers over the mountains.
Temperatures are expected to be generally near or above seasonal
averages. For Christmas Eve and Christmas Day...a Pacific storm
system will affect much of the region. At this time, it appears
that anticipated snow amounts west of a line from Cut Bank to
Lewistown should see 3 to 5 inches of snow over the plains with 6
to 15 inches in the mountains. For areas east of this line...snow
accumulations should range from 1 to 4 inches over the plains with
3 to 8 inches in the mountains. It should be noted that the record
snowfall for Great Falls on Christmas day is only 4.4 inches...and
we might have a chance at that record should a heavier snowband
move through Great Falls. Overall this is not a major storm...but
the timing for precipitation during a major holiday period will
affect travel. Temperatures will also trend colder from Wednesday
through Friday. There is the chance that temperatures on Christmas
Day could be a bit colder than currently forecast because of
clouds/snowfall. After this storm exits the region late
Thursday/early Friday...the weather pattern will become a bit less
active. There will be a small chance for a passing snow shower
over the weekend and into the New Years week...but no significant
snowfall is expected at this time. The main concern tonight is the
GFS13/EC are hinting at some very cold air moving into the region
by Tue Dec 30th...again this is a ways out...and things can change
a bit...but at this time current models are trying to bring down
another batch of arctic air before New Years. Brusda/mpj
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 33 49 31 39 / 20 50 30 30
CTB 26 43 28 36 / 20 40 30 20
HLN 30 47 31 38 / 50 80 40 30
BZN 27 45 27 34 / 70 90 50 30
WEY 30 39 21 31 / 100 100 90 50
DLN 34 46 29 35 / 70 90 60 30
HVR 24 44 27 38 / 20 70 20 20
LWT 31 48 30 37 / 30 80 40 30
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 7 PM this evening to 5 AM MST
Monday FOR ELEVATIONS ABOVE 5000 FEET FOR Central and Southern
Lewis and Clark...Jefferson...Northern Rocky Mountain Front...
Southern Rocky Mountain Front.
HIGH WIND WATCH from late tonight through Sunday afternoon
Eastern Glacier...Eastern Pondera...Eastern Teton...Liberty...
Toole.
HIGH WIND WARNING until 5 PM MST Sunday Northern Rocky Mountain
Front...Southern Rocky Mountain Front.
WINTER WEATHER ADVISORY from 7 PM this evening to 5 AM MST
Monday FOR ELEVATIONS ABOVE 5500 FEET FOR Beaverhead...
Broadwater...Cascade...Gallatin...Judith Basin...Madison...
Meagher.
&&
$$
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AREA FORECAST DISCUSSION
NWS HASTINGS NE
1207 AM CST SUN DEC 21 2014
.UPDATE...
ISSUED AT 630 PM CST SAT DEC 20 2014
DENSE FOG IS ONCE AGAIN BEGINNING TO SETTLE IN OVER OUR EASTERN
FORECAST AREA BASED ON OBSERVATIONS AT GRI...JYR...AND AUH...WHICH
HAVE ALL GONE DOWN TO 1/4 SM IN THE LAST HOUR. FORECAST MODELS
INCLUDING THE RAP...HRRR...AND SREF ARE ALL INDICATING THE
POTENTIAL OF DENSE FOG FROM THE HASTINGS AND GRAND ISLAND AREAS
AND POINTS OFF TO THE NORTH AND EAST FROM THERE. IT IS HARD TO SAY
HOW FAR WEST AND SOUTH THE DENSE FOG WILL DEVELOP...BUT THERE IS
LESS MODEL SUPPORT FOR DENSE FOG AS YOU GET SOUTH AND WEST OF
HASTINGS. IT IS POSSIBLE THAT THE DENSE FOG ADVISORY MAY BE
EXPANDED TO THE SOUTH AND WEST LATER IN THE NIGHT BUT CONFIDENCE
IS NOT THERE TO GO ANY FURTHER SOUTH AND WEST WITH THE ADVISORY AT
THIS POINT IN TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 336 PM CST SAT DEC 20 2014
SATELLITE SHOWS THE AREA OF PERSISTENT STRATUS IN THE EASTERN PART
OF THE FORECAST AREA HAS MOVED LITTLE IN THE PAST COUPLE HOURS BUT
THE THE HIGH CLOUDS MOVING OVER FROM THE WEST THE STRATUS IS
BECOMING MORE DIFFICULT TO SEE. IN THE STRATUS TEMPERATURES CONTINUE
TO STRUGGLE IN THE 30S...BUT AREAS WITH SUNSHINE HAVE WARMED MORE
THIS AFTERNOON.
MAIN CONCERN WITH THIS PERIOD ONCE AGAIN IS THE FOG CHANCES FOR
TONIGHT. A WEAK UPPER LEVEL WAVE MOVES THROUGH THE FORECAST AREA
LATE TONIGHT INTO SUNDAY. WITH THIS EXPECT THERE TO BE SOME HIGHER
CLOUDS THAT MOVE INTO THE AREA...BUT DRY CONDITIONS ARE EXPECTED.
THE LOW LEVEL MOISTURE CONTINUES ACROSS MUCH OF THE AREA THROUGH THE
NIGHT AND INTO SUNDAY. THE STRATUS SEEMS TO BE THE MOST PERSISTENT
IN THE NORTHEAST PART OF THE FORECAST AREA. THE RAP RELATIVE
HUMIDITY AT 925MB HAS BEEN FOLLOWING THE STRATUS THE BEST THIS
AFTERNOON AND THROUGH MOST OF THE NIGHT THE NORTHEAST REMAINS WITH
CLOUDS. IN THE SOUTHEAST THE HIGHER RELATIVE HUMIDITY BUILDS BACK
INTO THE AREA LATE TONIGHT. EXPECT THERE COULD BE SOME FOG NEAR THE
EDGES OF THE STRATUS. WILL KEEP PATCHY FOG ACROSS ALL BUT THE FAR
WEST AND AREAS OF FOG IN THE EAST WHERE THERE IS THE BEST CHANCE FOR
FOG SINCE VISIBILITY AT KJYR STILL HAS LOW VISIBILITY. ONCE AGAIN
THERE IS A POTENTIAL FOR SOME LOWER VISIBILITIES LATE TONIGHT INTO
SUNDAY MORNING AND EXPECT THE EAST IS THE BEST CHANCE.
BY SUNDAY MORNING THE WINDS WILL INCREASE A LITTLE BIT FROM THE
SOUTH. THIS WILL HELP TO MIX THINGS UP A BIT AND THE FOG AND STRATUS
MAY FINALLY MOVE OUT OF THE AREA.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 336 PM CST SAT DEC 20 2014
THE BIGGEST CHALLENGE WILL BE DETERMINING PRECIPITATION CHANCES.
WE KICK OFF THE LONG TERM SUNDAY NIGHT WITH A LONGWAVE TROUGH AXIS
OVER THE GREAT PLAINS...AS A STRONG JET HEADS IN ON THE BACKSIDE OF
THE TROUGH..FROM THE PACIFIC NORTHWEST INTO THE GREAT BASIN. MOST OF
THE ENERGY IS ASSOCIATED WITH THE CLOSED LOW IN THE NORTHERN
PLAINS...SO I AM NOT GOING ALL THAT HIGH WITH CHANCES HERE. A
SMALLER SHORTWAVE TROUGH WITHIN THE LONGWAVE TROUGH WILL HELP KICK
SOMETHING UP IN THE EVENING...THE WAY IT LOOKS NOW...BUT SMALL
FEATURES ARE DIFFICULT TO BE VERY EXACT WITH TIMING. KEEPING THIS
ALL RAIN AS TEMPERATURES DO NOT APPEAR TO BECOME COLD ENOUGH BEFORE
THE PRECIPITATION EXITS WITH THIS PERTURBATION. ANOTHER PERTURBATION
WORKS AROUND THE TROUGH BY MONDAY NIGHT/TUESDAY. TEMPERATURE
PROFILES APPEAR TO SUPPORT SOME LIGHT SNOW MONDAY NIGHT INTO
TUESDAY. PRECIPITATION/SNOW AMOUNTS ARE EXPECTED TO BE LIGHT...WITH
SNOW ACCUMULATION NO MORE THAN AN INCH ANTICIPATED WITH THIS NEXT
PIECE OF ENERGY. AGAIN...CONFIDENCE IS NOT THE HIGHEST WITH
EXACT TIMING.
FLOW IS QUITE PROGRESSIVE AND YET ANOTHER TROUGH MAKES ITS WAY INTO
THE ROCKIES. A PIECE OF ENERGY IS EXPECTED TO BREAK OFF AHEAD OF THE
MAIN WAVE...BUT LOOKS MORE FOCUSED JUST NORTH OF THE CWA. WE COULD
GET SOME SNOW OUT OF THIS...BUT AGAIN...DOES NOT LOOK LIKE WE WILL
GET A LOT OUT OF SNOW. WE SHOULD GET A NOTICEABLE COOL DOWN FRIDAY
BEHIND THE ASSOCIATED COLD FRONT. HIGHS WILL ONLY BE IN THE LOWER TO
MID 30S AND THE WIND COULD BE QUITE GUSTY FROM THE
NORTHWEST...MAKING THE DAY AFTER CHRISTMAS POTENTIALLY BRISK AND
UNCOMFORTABLE.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1207 AM CST SUN DEC 21 2014
LIFR CONDITIONS FORECAST AT KGRI TONIGHT INTO SUNDAY MORNING. VFR
CONDITIONS CURRENTLY FORECAST AT KEAR THROUGH THE NEXT 24 HOURS.
A PERSISTENT BAND OF STRATUS IS NOTED OVER EASTERN NEBRASKA THIS
EVENING...WITH THE WESTERN PERIPHERY OF THIS STRATUS SHIELD
EXTENDING FROM NEAR KODX TO NEAR KGRI AND KHSI. FOG...SOME OF
WHICH IS DENSE...ALSO EXISTS WITHIN THIS STRATUS AND COULD IMPACT
KGRI TONIGHT INTO SUNDAY MORNING. GIVEN ALL THIS...WENT AHEAD WITH
LIFR CONDITIONS AT KGRI UNTIL 17Z...WITH MVFR CONDITIONS THEN
EXPECTED AS STRATUS PERSISTS OVER THE AREA DURING THE DAY SUNDAY.
ANOTHER ROUND OF LIFR CONDITIONS ARE FORECAST AT KGRI STARTING 01Z
MONDAY AS GUIDANCE SUGGESTS ANOTHER ROUND OF STRATUS WILL IMPACT
THE AREA. AS FOR KEAR...STRATUS IS CURRENTLY SITUATED TO THE EAST
AND GUIDANCE SUGGESTS THIS WILL NOT CHANGE. GIVEN THIS...WENT
AHEAD WITH VFR CONDITIONS AT KEAR THROUGH THE NEXT 24 HOURS.
OBVIOUSLY THIS WILL NEED TO BE CLOSELY MONITORED TO ENSURE THE
STRATUS DOES NOT MAKE A PUSH TO THE WEST TONIGHT INTO SUNDAY
MORNING. THE SURFACE WIND WILL REMAIN FROM THE SOUTH OR SOUTHWEST
DURING THE TAF PERIOD...STARTING AT AROUND 07KTS TO START THE TAF
PERIOD BUT INCREASING TO NEAR 15KTS DURING THE DAY SUNDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 11 AM CST SUNDAY FOR NEZ039>041-047>049-
062>064-075>077-087.
KS...NONE.
&&
$$
UPDATE...WESELY
SHORT TERM...JCB
LONG TERM...HEINLEIN
AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
853 PM EST MON DEC 22 2014
.SYNOPSIS...
TODAY MAY BE THE DAY WE MAY SEE A FEW BREAKS CLOUDS AND SOME
SUNSHINE. BUT... A SURFACE LOW DEVELOPING OVER THE NORTHERN
MIDWEST IN COMBINATION WITH A LOW MOVING UP THE EAST COAST WILL
BRING A PERIOD OF LIGHT MIXED PRECIPITATION TONIGHT...FOLLOWED BY
RAIN TUESDAY THROUGH WEDNESDAY WITH MOSTLY CLOUDY SKIES. GUSTY
WINDS ARE EXPECTED CHRISTMAS DAY...WITH LINGERING RAIN SHOWERS
MIXING WITH SNOW SHOWERS.
&&
.NEAR TERM /THROUGH TUESDAY/...
850 PM UPDATE...
OPTED FOR A SHORT TERM SPECIAL WEATHER STATEMENT FOR THE LOWER
TWO-THIRDS OF OUR FORECAST AREA.
RAIN SHOWERS ARE STREAMING INTO NY AND PA ATTM. IN THE NORMALLY
COOLER VALLEY LOCALES AND ON THE HIGH ELEVATIONS, TEMPERATURES ARE
BETWEEN 30 AND 34 DEGREES. THEREFORE ISOLATED LIGHT FREEZING RAIN
IS EXPECTED THROUGH THE EVENING HOURS.
JUDGING BY THE LATEST RAP AND THE CURRENT OBS TREND, TEMPERATURES
SHOULD WARM ABOVE THE FREEZING MARK BY 11 PM OR MIDNIGHT.
150 PM EST UPDATE...
CLOUDS ARE SLOWLY BUT SURELY BREAKING UP ACROSS THE WESTERN HALF
OF THE CWA THIS AFTERNOON. THE SHORTWAVE PASSING TO THE NORTH HAVE
FINALLY MANAGED TO BREAK UP THE CLOUDS AND IT FEELS GREAT TO
FINALLY SEE THE SUN... EVEN IF IT ONLY LASTS FOR A SHORT AMOUNT OF
TIME. SADLY... IT WILL NOT LAST FOR LONG AS OUR NEXT SYSTEM IS
ABOUT TO IMPACT THE REGION.
UNCERTAINTIES STILL EXIST WITH THE FRONT OF OF THE APPROACHING
STORM. ONE BIG FORECAST QUESTION FOR TONIGHT IS WILL TEMPS BE COLD
ENOUGH TO CREATE HAZARDOUS CONDITIONS. TEMPS ATTM ARE FAIRLY
WARM... AS IN 5 TO 10 DEGREES ABOVE FREEZING... EXCEPT FOR THE
HIGHER TERRAIN WHERE TEMPS HAVE RISEN CLOSE TO THE FREEZING MARK.
WE MAY COOL A FEW DEGREES WHEN THE SUN SETS DUE TO LOSS OF DIURNAL
HEATING AND WITH WET BULB EFFECT AS THE PRECIP FALLS... BUT EVEN
THEN WILL BE WARM ADVECTING.
WE DO EXPECT PRECIP TO START TONIGHT IN THE FORM OF A WINTRY MIX
OF FREEZING RAIN/SNOW/RAIN AND MAYBE SLEET. BUT THE OTHER FORECAST
PROBLEM FOR THE NIGHT IS WILL TEMPS AND ROADS STAY COLD ENOUGH
LONG ENOUGH FOR HAZARDOUS CONDITIONS TO DEVELOP FOR A PROLONGED
PERIOD OF TIME. ATTM CONFIDENCE IS NOT HIGH ENOUGH THAT THIS WILL
BE THE CASE. THUS... WE HAVE DECIDED TO NOT ISSUE AN ADVISORY FOR
TONIGHT. BELIEVE IT WOULD BE MORE APPROPRIATE FOR A SPS ISSUANCE
ENVIRONMENT.
BEFORE MIDNIGHT TONIGHT... EXPECT FREEZING RAIN/SNOW MIX. AFTER
MIDNIGHT EXPECT MORE OF WET SNOW EXCEPT FOR THE HIGHEST
ELEVATIONS... THEY MAY SEE MORE OF A VERY LIGHT FREEZING RAIN
THROUGH 4AM. BY 12Z TUESDAY EXPECT MOST ARES TO TRANSITION OVER TO
RAIN.
TEMPS THROUGH LATE TONIGHT ARE EXPECTED TO REMAIN IN THE LOW TO
MID 30S.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
255 PM EST UPDATE...
UNSETTLED WEATHER WILL BE THE MAIN THEME FOR THIS FORECAST PERIOD
AS A SFC LOW/OCCLUDED FRONT SLOWLY PUSHES IT`S WAY ACROSS THE
NORTHEAST.
TUESDAY MORNING... THE FIRST BATCH OF RAIN SHOWERS WITH THE
APPROACHING STORM SYSTEM WILL JUST START TO PUSH INTO THE AREA.
FOR THE MOST PART BY TUESDAY MORNING ALL PRECIP WILL BE RAIN. IF
THERE STILL ANY LINGERING WINTRY PRECIP FROM THE NIGHT BEFORE...
IT WILL QUICKLY TRANSITION OVER TO RAIN BY 15Z TUESDAY. TUESDAY
WILL HAVE FAIRLY LIGHT ACCUMULATIONS AROUND A HALF AN INCH OR LESS.
WAA WILL ALSO CONTINUE PREVAIL OVR THE REGION TUES INTO WED AS WE
REMAIN IN SOUTHERLY FLOW AHEAD OF THE UPPR LVL TROUGH. THIS WILL
RESULT IN UNSEASONABLY WARM TEMPERATURES OVER NY AND PA. TEMPS
WILL RISE INTO THE MID 40S ON TUESDAY AND CONTINUE TO RISE ON WED.
TEMPS ARE EXPECTED TO REACH THE UPPR 40S TO LOW 50S WED
AFTERNOON... THEN RISE INTO THE LOW TO MID 50S BY WED NIGHT. THE
REASON WHY WE WILL CONTINUE TO SEE A RISE IN TEMPS ACROSS THE CWA
WED NIGHT IS BECAUSE WE WILL HAVE A STRONG LLJ AROUND 40 TO 50
KNOTS. NOT ONLY WILL THIS INCREASE THE TEMPS IT WILL SEE A STRONG
INFLUX OF MOISTURE ACROSS THE NORTHEAST. WE ARE EXPECTED TO SEE
PWAT VALUES AROUND 4 STANDARD DEVIATIONS ABOVE NORMAL. THIS WILL
RESULT IN RAIN SHOWERS BECOMING HEAVY AT TIMES.
RAIN SHOWERS ARE EXPECTED TO PREVAIL THROUGH THE WHOLE FORECAST
PERIOD AS THE OCCLUDED FRONT WILL NOT PUSH COMPLETELY THROUGH THE
AREA TILL THURS. DO NOT EXPECT WATER PROBLEMS DUE TO LOW LIQUID
RATIOS IN SNOW PACK ACROSS OVR NY AND PA.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
STRONG COLD FRONT PASSES THE REGION THURSDAY MORNING. MODELS ARE
IN REASONABLE AGREEMENT WITH THIS FEATURE AND SUGGEST THE MOST
SIGNIFICANT IMPACT WILL BE SW-W WINDS IN THE STRONG COLD ADVECTION
THURSDAY AFTERNOON. WINDS MAY GUST AT TIMES 35-45 MPH. THERE IS
ALSO A GOOD SIGNAL SHOWING UP FOR A NARROW COLD FRONTAL RAIN BAND
PHENOMENA MOVING THROUGH BETWEEN 12Z-18Z. THIS FEATURE ALONE MAY
CAUSE CONVECTIVE WIND ACCELERATIONS AND SCATTERED DAMAGE/POWER
OUTAGES. LOOKING FOR A NON-DIURNAL TEMPERATURE TREND FROM WEDS
NIGHT-THURSDAY WITH MAXES FOR WEDS/THURS PROBABLY A FEW HOURS
EITHER SIDE OF MIDNIGHT AS STRONG WARM SECTOR SURGES INTO AREA.
OUTSIDE OF THIS FEATURE...THE TEMPERATURES ARE TRENDING SLIGHTLY
WARMER SO A CHANGEOVER FROM PERIODS OF RAIN TO SCATTERED RAIN/SNOW
SHOWERS SEEMS MORE LIKELY THAN A SHARP TURNOVER TO ALL SNOW. IN
FACT...A SIGNIFICANT DRY SLOT MAY CUT PRECIPITATION OFF FOR MUCH
OF THE MORNING BEFORE THE INSTABILITY SHOWERS ASSOCIATED WITH THE
COLD POOL KICK IN FOR THURSDAY AFTERNOON AND NIGHT.
THE REMAINDER OF THE WEEK FEATURES SOME WEAK LAKE EFFECT RESPONSE
MAINLY NORTH OF CENTRAL NY ON FRIDAY...THEN RIDGING AND GENERALLY
NEAR TO ABOVE NORMAL TEMPERATURES INTO SATURDAY. BIG MODEL
DISCREPANCIES THEN CONTINUE TO SHOW UP BETWEEN THE ECMWF AND GFS
WHERE THE ECMWF BRINGS A QUICK TN VALLEY RUNNER TO THE MIDDLE
ATLANTIC COAST BY SUNDAY AFTERNOON. THE GFS AND GEFS ENSEMBLES
FEATURE A MUCH FLATTER SWLY FLOW AND SFC HIGH PRESSURE. THE
CANADIAN GGEM DEFINITELY LEANS WITH THE EURO WITH LOW PRES ON THE
COAST SUNDAY AFTERNOON. AT THIS TIME...WILL BLANKET WITH LOW CHC
POPS FOR SNOW SHOWERS GIVEN THE HIGH LVL OF UNCERTAINTY.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
00Z TUE UPDATE... OTHER THAN LINGERING VFR CONDS THIS EVE AT
KSYR...KRME...KELM...AND KITH...CONDS SHOULD BE DETERIORATING WITH
TIME OVERNIGHT...OWING TO LWR CIGS...AS WELL AS PATCHY LGT PCPN.
ONCE LWR CONDS BECOME ESTABLISHED...THEY ARE LIKELY TO PERSIST
THROUGH THE END OF THE VALID TAF PD (00Z WED).
FOR THE MOST PART...MVFR/FUEL ALT REQD RESTRICTIONS ARE EXPECTED.
HOWEVER...IFR CIG BASES ARE ALSO FORESEEN FOR A TIME AT KAVP AND
KBGM OVERNIGHT.
AS FAR AS PTYP IS CONCERNED...A BRIEF PD OF -FZDZ COULD OCCUR...MAINLY AT
KBGM/KITH/KRME...THROUGH 06-08Z TUE. THEREAFTER...LOW-LVL TEMPS
SHOULD WARM ENUF TO SUPPORT ONLY -RA/-DZ.
LLWS IS ALSO ANTICIPATED OVERNIGHT INTO EARLY TUE AT KAVP AND
KELM...WHERE SFC WINDS ARE THE WEAKEST...AND OVERRUN BY 30-40 KT
FLOW AT ARND 2 THSD FT AGL. DURG THE DAY TUE...SFC WINDS SHOULD
INCREASE AREA-WIDE TO 8-12 KT...WITH FLOW ALSO LESSENING A BIT AT
2-3 THSD FT AGL.
OUTLOOK...
TUE NGT TO THU... MVFR LIKELY...CHANCE IFR. PERIODS OF RAIN. VERY
WINDY THURSDAY AFTERNOON.
FRI/SAT...VFR. CHC SHRA SAT.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KAH
NEAR TERM...DJP/KAH
SHORT TERM...KAH
LONG TERM...JAB
AVIATION...JAB/MLJ
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1027 PM EST MON DEC 22 2014
.SYNOPSIS...A COLD AIR DAMMING RIDGE WILL REMAIN LOCKED IN PLACE
EAST OF THE APPALACHIANS THROUGH TUESDAY. A WARM FRONT WILL LIFT
NORTHWARD THROUGH THE REGION LATE TUESDAY NIGHT AND WEDNESDAY AS A
DEVELOPING LOW PRESSURE SYSTEM STRENGTHENS WEST OF THE MOUNTAINS.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 1025 PM MONDAY...
TONIGHT: WV SATELLITE AND UPPER AIR DATA THIS EVENING REVEAL A
STRONGLY DIGGING/AMPLIFYING TROUGH OVER THE EASTERN ROCKIES...WITH
PERTURBED SOUTHWESTERLY FLOW EAST OF THE TROUGH AXIS FROM THE EAST
PACIFIC TO THE EASTERN US COAST. ONE SUCH PERTURBATION AND
ASSOCIATED AREA OF SHOWERS FROM NE GA AND THE SC UPSTATE WILL TRACK
NE ACROSS THE WESTERN PIEDMONT TONIGHT...AND IN CONJUNCTION WITH A
STRONG 925 MB FRONTAL ZONE OVER THE PIEDMONT CHARACTERIZED BY A 13 C
TEMP DIFFERENTIAL BETWEEN GSO AND MHX PER 00Z RAOB DATA...WILL
SUPPORT PERIODS OF RAIN OVER THE WESTERN PIEDMONT. UPSTREAM HOURLY
RAINFALL AMOUNTS SUPPORT THE LATEST RAP AND HRRR QPF OF AROUND A
TENTH TO TWO TENTHS OF ADDITIONAL RAIN...VERSUS LIGHTER AMOUNTS
NOTED BY THE EC/GFS/NAM. OTHERWISE AND ELSEWHERE...PERIODS OF
NORTHERLY 5-10 MPH WIND-BLOWN DRIZZLE...AND A CHANCE OF MEASURABLE
RAIN...WILL PREVAIL. A SATURATED AND NEAR-FULLY WET-BULBED LOWEST
SEVERAL THOUSAND FT...OWING TO CAD FROM A PARENT 1032 MB SURFACE
HIGH NEAR NOVA SCOTIA...WILL SUPPORT LITTLE VARIATION IN
TEMPERATURES FROM THEIR 10 PM READINGS IN THE MIDDLE 30S TO AROUND
40 DEGREES. -MWS
AS OF 300 PM MONDAY...
TUESDAY...NO MECHANISM NOTED TO SCOUR OUT THE CAD AIR MASS SO EXPECT
A CONTINUATION OF THE EXTENSIVE OVERCAST WITH PATCHES OF LIGHT
RAIN/DRIZZLE. EXPECT TO SEE A NOTEWORTHY INCREASE IN RAIN COVERAGE
AND INTENSITY LATE IN THE DAY AS S/W (NOW CROSSING CENTRAL TX)
ADVANCES EAST TOWARD OUR REGION. THIS FEATURE WILL INCREASE
DIVERGENCE ALOFT AS WELL AS INCREASE ISENTROPIC UPGLIDE IN THE LOWER
LAYERS OF THE ATMOSPHERE. THESE FACTORS IN COMBINATION WITH PRECIP
WATER VALUES WELL ABOVE NORMAL SHOULD RESULT IN AREAS OF MODERATE-
BRIEFLY HEAVY RAINFALL LATE IN THE DAY OR EARLY EVENING ACROSS THE
WESTERN PIEDMONT.
DAYTIME TEMPS WILL REMAIN WELL BELOW NORMAL. USED THE HIGH RES WRF-
ARW FOR HOURLY TEMPS AS GFS-BASED GUIDANCE APPEARS TO BE ERODING THE
CAD (AND ITS LINGERING EFFECTS) TOO QUICKLY. TEMPS BY LATE AFTERNOON
SHOULD VARY FROM THE UPPER 30S/LOWER 40S OVER THE PIEDMONT TO NEAR
50 OVER THE FAR SE.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...
A POWERFUL 175KT PACIFIC JET DIGGING THROUGH THE WESTERN US WILL
HELP TO CARVE OUT A HIGH AMPLITUDE TROUGH OVER THE CENTRAL US...WITH
AN EMBEDDED SOUTHERN STREAM CLOSED LOW. AN ALMOST EQUALLY POWERFUL
JET WILL EVOLVE OVER THE EASTERN US ON THE LEADING SIDE OF THE UPPER
TROUGH WHICH WILL BE THE IMPETUS FOR A WET AND UNSETTLED PERIOD
TUESDAY NIGHT THROUGH CHRISTMAS EVE AS THE UPPER TROUGH AND
ATTENDANT COLD FRONT MOVES SLOWLY EAST-NORTHEASTWARD THROUGH THE
REGION EARLY CHRISTMAS DAY.
IN ADVANCE OF THE HIGH AMPLITUDE LONGWAVE TROUGH AND ATTENDANT SFC
COLD FRONT...DEEP INFLUX OF PACIFIC MOISTURE...SUPPLEMENTED WITH A
LOW-LEVEL CARIBBEAN FEED...WILL ADVECT ANOMALOUSLY HIGH PWATS OF 1.5-
1.7" INTO THE AREA TUESDAY NIGHT-WEDNESDAY(WITHIN THE 99TH
PERCENTILE WITH THE HIGHEST OBSERVED DEC PWAT DATING BACK TO 1948 IS
1.59"-12/21/1991). THIS STRONG MOISTURE FLUX CONVERGENCE ALONG THE
NORTHWARD RETREATING WARM FRONT...AND ENHANCED LOCALLY OVER THE MORE
STEEPLY SLOPED PORTION OF THE LINGERING COLD DOME WILL RESULT IN A
WIDESPREAD SOAKING RAIN OF 1-2"...HEAVY AT TIMES TUESDAY NIGHT AND
INTO CHRISTMAS EVE MORNING. ONCE THE WARM FRONT LIFTS NORTHWARD INTO
THE VIRGINIA...THERE WILL LIKELY BE A LULL IN PRECIP DURING THE DAY
WITH BREEZY CONDITIONS DEVELOPING IN THE WARM SECTOR. THEN BY LATE
AFTERNOON AND INTO THE EVENING(BETWEEN 00Z-06Z THURSDAY)....THE EAST-WEST
PASSAGE OF THE COLD FRONT AND ACCOMPANYING BAND OF SHOWERS AND POSSIBLY
A FEW THUNDERSTORMS WILL BRING ONE LAST ROUND OF RAIN INTO THE AREA.
SEVERE POTENTIAL: EVALUATING SEVERE POTENTIAL IN A LOW CAPE-HIGH
SHEAR ENVIRONMENT IS ALWAYS A CHALLENGE...EVEN AT CLOSER TIME SCALES
OF 6-12 HOURS. THE LULL IN PRECIP DURING MUCH OF THE DAYTIME
HOURS...MAY ALLOW FOR SOME MODEST HEATING...ESPECIALLY FROM THE US 1
CORRIDOR EASTWARD...WHICH COULD LEAD TO BETTER DESTABILIZATION THAN
WHAT MODELS CURRENTLY SHOW(100-200J/KG MUCAPE). GIVEN STRONG SHEAR
ALONE...CANNOT RULE OUT AN ISOLATED SEVERE...BUT WEAK LAPSE RATES
ALOFT OF 5.0-5.5 C/KM ALONG WITH THE MAIN DYNAMICS PASSING OVER THE
GREAT LAKES WILL LIMIT A MORE ROBUST SEVERE THREAT. ADDITIONALLY...
IF WE SEE WIDESPREAD RAINFALL AMOUNTS NEAR THE HIGHER SIDE OF THE
EXPECTED QPF OF 2.0"...MINOR FLOODING WILL BE POSSIBLE ACROSS
PORTIONS OF THE NEUSE AND TAR. SEE HYDROLOGICAL DISCUSSION BELOW FOR
ADDITIONAL DETAILS.
TEMPERATURES VERY CHALLENGING WITH HIGH BUST POTENTIAL...DEPENDENT
ON EVOLUTION/TIMING/LOCATION OF THE RETREATING WEDGE FRONT INTO THE
CLIMATOLOGICALLY FAVORED AREA ACROSS THE FAR NW PIEDMONT TUESDAY
NIGHT AND INTO THE DAY ON WEDNESDAY. SUCH A STRONG CAD EVENT WOULD
STRONGLY SUGGEST FAVORING THE COOLER NAM/MET GUIDANCE THROUGH EARLY
WEDNESDAY WITH THE WELL KNOWN MODEL BIAS OF ERODING THE CAD TOO
QUICKLY. LOWS TUESDAY NIGHT WILL LIKELY OCCUR EARLY IN THE NIGHT
WITH RISING TEMPERATURES THEREAFTER IN ALL BUT THE FAR NW PIEDMONT
THROUGH DAYBREAK. A LARGE RANGE IN TEMPERATURES ARE EXPECTED ON
WEDNESDAY WITH THE POTENTIAL FOR THE SHALLOW WEDGE AIRMASS TO HOLD
ON ACROSS THE EXTREME NW CORNER...KEEPING TEMPS IN THE 50S. THE
REMAINDER OF THE FORECASTER AREA WILL BE IN THE WARM SECTOR WITH
HIGHS IN THE UPPER 60S ACROSS THE CENTRAL PIEDMONT...AND LOWER 70S
ACROSS THE SANDHILLS AND COASTAL PLAIN. CLEARING AND COOLING
WEDNESDAY NIGHT IN THE WAKE OF THE COLD FRONT LOOKS A BIT DELAYED
THAN WHAT MODELS WERE SHOWING A DAY OR TWO AGO. NOT AS COOL AS WE
ORIGINALLY THOUGHT. LOWS IN THE MID TO UPPER 40S NW TO MID 50S SE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...
DEEPENING SURFACE LOW LIFTING NEWD INTO SE CANADA WILL RESULT IN
BREEZY CONDITIONS ON CHRISTMAS DAY. OTHERWISE DRY WITH SEASONABLY
MILD TEMPERATURES CONTINUING INTO FRIDAY AS HIGH PRESSURE BUILDS IN
FROM THE NORTHERN GULF.
MODEL SPREAD BEGINS TO INCREASE DRAMATICALLY LATE FRIDAY THROUGH THE
WEEKEND...WITH THE EC MUCH DEEPER WITH THE NEXT MID/UPPER LEVEL
TROUGH...RESULTING IN YET ANOTHER WET AND UNSETTLED PERIOD LATE AS
IT TRACKS AN AREA OF LOW PRESSURE ACROSS THE SOUTHERN/CENTRAL
APPALACHIANS LATE SATURDAY AND INTO SUNDAY. THE GFS REMAINS MUCH
FLATTER WITH THE UPPER TROUGH...PRODUCING LITTLE TO NO PRECIP OVER
THE CAROLINAS. WILL INDICATE SLIGHT CHANCE POPS UNTIL BETTER
AGREEMENT IS REACHED. COOLER TO SLIGHTLY BELOW NORMAL TEMPERATURES
ARE EXPECTED BEHIND THE FRONT EARLY NEXT WEEK.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 715 PM MONDAY...
AVIATION CONDITIONS WILL REMAIN POOR WELL ON THROUGH TONIGHT AND
TUESDAY...WITH PERIODS OF RAIN/DRIZZLE AND A LIGHT NORTHEASTERLY
WIND ALONG WITH THE ALREADY LOW CLOUDS AND LIMITED VSBYS. THERE IS
HIGH CONFIDENCE OF LIFR CONDITIONS THROUGH THE NIGHT AND THERE MAY
ALSO BE SOME VLIFR CONDITIONS RESULTING FROM FOG BETWEEN 06Z AND 12Z.
THERE WILL BE NO CHANGE IN THE AIRMASS OVER NC ON TUESDAY...SO ONLY
MINIMAL IMPROVEMENT IN CONDITIONS IS EXPECTED. CEILINGS MAY LIFT A
LITTLE DURING THE AFTERNOON ALLOWING IFR CONDITIONS TO DEVELOP...BUT
CONFIDENCE IN THIS IS LOW GIVEN HOW LITTLE CONDITIONS CHANGED
EARLIER TODAY. PERIODS OF LIGHT RAIN AND DRIZZLE WILL CONTINUE.
OUTLOOK... AN UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT WILL
APPROACH THE REGION TUESDAY NIGHT AND WEDNESDAY...LEADING TO AN
INCREASED CHANCE OF SHOWERS...ALONG WITH GUSTY WINDS AND A FEW
ISOLATED THUNDERSTORMS (MAINLY OVER EASTERN NC). THUS...AVIATION
CONDITIONS WILL REMAIN POOR THROUGH AT LEAST WEDNESDAY....BEFORE A
COLD FRONT CROSSES THE AREA LATE WEDNESDAY NIGHT AND EARLY THURSDAY.
BEHIND THE FRONT...BLUSTERY WESTERLY WINDS WILL OCCUR CHRISTMAS DAY
WITH GUSTS 30-35KTS POSSIBLE. OTHERWISE VFR CONDITIONS EXPECTED TO
RETURN CHRISTMAS DAY AND PERSIST THROUGH SATURDAY.
&&
.HYDROLOGY...
AS OF 230 PM MONDAY...
ANTECEDENT RAINFALL OVER THE PAST 24 HOURS RANGED FROM A MINIMA OF
ABOUT A TENTH OF AN INCH IN THE NORTHWEST PIEDMONT (THE UPPER
YADKIN/PEE DEE AND UPPER HAW RIVER BASINS) TO A STRIPE OF 1 INCH
PLUS ACROSS THE SOUTHEAST (THE CENTRAL NEUSE AND CENTRAL CAPE FEAR
BASINS). WILL SEE ONLY MINOR RISES ON THE MAINSTEM RIVERS IN
RESPONSE...BUT THIS IS THE 3RD FAIRLY SIGNIFICANT RAINFALL EVENT
(>0.5 INCHES) OVER THE AREA SINCE 12/10. RELATIVE SOIL MOISTURE
PERCENTAGES IN THE 0-200 CM COLUMN HAVE BEEN INCREASING...WITH
HIGHER PERCENTILES NEARER THE SURFACE...SO QUICKER RUNOFF IS
EXPECTED FROM OUR UPCOMING RAIN EVENT.
CURRENT QUANTITATIVE PRECIP FORECASTS FROM THE GEFS AND NAEFS
ENSEMBLES ARE IN LOCKSTEP AGREEMENT AT PRESENT...WITH HEAVIEST RAIN
(~1.3-1.5 INCHES) FROM TOMORROW NIGHT THROUGH CHRISTMAS MORNING.
RAINFALL AMOUNTS IN THIS RANGE COULD POTENTIALLY CAUSE SOME MINOR
FLOODING ON THE NEUSE RIVER AND TAR RIVER LATE ON CHRISTMAS
DAY...BUT IT WOULD BE LOW IMPACT WITH THOSE RIVERS BARELY REACHING
MINOR FLOOD STAGE. THE UPSHOT...RIVER FLOODING WILL ONLY BE AN ISSUE
IF RAINFALL FORECASTS BEGIN TRENDING HIGHER...INTO THE 2 INCH PLUS
RANGE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...MWS/WSS
SHORT TERM...CBL
LONG TERM...CBL
AVIATION...BLS
HYDROLOGY...MLM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
312 PM CST SUN DEC 21 2014
.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 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 312 PM CST SUN DEC 21 2014
PERIODS OF VLIFR-IFR CONDITIONS WILL PERSIST OVER EASTERN
TERMINALS INCLUDING KJMS THROUGH MUCH OF THE PERIOD...WITH LOW
STRATUS AND FOG SPREADING SLOWLY NORTH AND WEST AND POSSIBLY
IMPACTING KBIS AND KMOT INTO THIS EVENING. LOW PRESSURE SYSTEM
WILL MOVE EAST AND BRING ANOTHER WARM FRONT EASTWARD ACROSS NORTH
DAKOTA TODAY. EXPECTING LIGHT RAIN AT KISN/KDIK THIS EVENING WITH
VFR CIGS...AND BETWEEN 02Z-06Z EXPECT PRECIPITATION TO CHANGEOVER
TO ALL SNOW. PRECIPITATION AT KMOT/KBIS AFTER 00Z COULD BE IN THE
FORM OF -FZRA OR -IP BEFORE CHANGING OVER TO ALL SNOW BY 06Z.
PREDOMINATELY VLIFR-IFR CONDITIONS AREA WIDE TONIGHT INTO MONDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM MIDNIGHT CST /11 PM MST/ TONIGHT TO
6 AM CST /5 AM MST/ TUESDAY FOR NDZ017-031>033-040-041-043-044.
&&
$$
SHORT TERM...NH
LONG TERM...AC
AVIATION...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1206 PM CST SUN DEC 21 2014
.UPDATE...
ISSUED AT 1206 PM CST SUN DEC 21 2014
NO MAJOR CHANGES FROM THE MID MORNING UPDATE. LOW STRATUS
CONTINUES TO VERY SLOWLY EXPAND WEST AND NORTH ACROSS THE JAMES
RIVER VALLEY OF NORTH AND SOUTH DAKOTA...WITH INCREASING MID LEVEL
CLOUDS WEST TO EAST. CHANCES FOR RAIN ON TRACK TO ENTER WEST
CENTRAL AND SOUTHWEST ND BETWEEN NOW AND 21Z. VIS AT KJMS SLIGHTLY
IMPROVED SO NO HEADLINES BUT WILL CONTINUE TO MONITOR.
UPDATE
ISSUED AT 1049 AM CST SUN DEC 21 2014
COMPLEX FORECAST OVER THE NEXT 24-36 HOURS. FOR THE MID MORNING
UPDATE MAIN CHANGE WAS TO INCREASE SKY COVER THROUGH THE DAY
ACROSS MY EAST ALONG WITH MENTIONING AREAS OF FOG. STRATUS
EXPANDING WEST AND NORTH ACROSS THE JAMES RIVER VALLEY WITH LOW
LEVEL MOISTURE ADVECTION WITH A SOUTH/SOUTHEAST WIND COMPONENT.
LAST FEW RUNS OF THE HRRR HANDLES THE STRATUS RATHER WELL SO WAS
UTILIZED. WILL NEED TO MONITOR VISIBILITIES IN CASE A DENSE FOG
ADVISORY IS NEEDED FOR THE JAMES VALLEY.
POPS ON TRACK WITH INCREASING CHANCES FOR PRECIPITATION IN THE
FORM OF RAIN SOUTHWEST AND A MIX NORTHWEST THIS AFTERNOON WITH THE
INCOMING STORM SYSTEM. FOR TONIGHT...CONTINUED THE TREND OF
STRATUS AND FOG EXPANDING WEST AND NORTH. ALSO...MODELS HINTING
RATHER STRONGLY AT LIGHT PRECIPITATION OVER MY EAST IN ADDITION TO
THE LIKELY/DEF POPS WEST. WE LOOK DRY ALOFT OVER MY EAST SO OPTED
TO MENTION FREEZING DRIZZLE WITH THE STRATUS AND FOG UNTIL WE
BECOME SATURATED OVERNIGHT.
UPDATE ISSUED AT 650 AM CST SUN DEC 21 2014
NO CHANGE IN FORECAST THINKING FOR THE REMAINDER OF THE DAY WITH
THE INCOMING 06 UTC GUIDANCE. THUS...BLENDED THE ONGOING FORECAST
TO OBSERVED TRENDS THROUGH 12 UTC.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 432 AM CST SUN DEC 21 2014
FIRST CONCERN IN THE SHORT TERM IS LINGERING FOG IN THE JAMESTOWN
AREA...AND THE POSSIBILITY OF FOG REFORMING IN THE TURTLE MOUNTAINS
TO THE MINOT AREA.
CURRENTLY A SURFACE LOW WAS CENTERED OVER SOUTHERN ALBERTA. A WARM
FRONT EXTENDED FROM THE LOW ACROSS SOUTHERN SASKATCHEWAN INTO
EASTERN NORTH DAKOTA...ASSOCIATED WITH THE LINGERING STRATUS AND
FOG. ANOTHER WARM FRONT EXTENDED FROM THE LOW SOUTHEASTWARD INTO
CENTRAL MONTANA AND EASTERN WYOMING. AT UPPER LEVELS...THE
ASSOCIATED SHORTWAVE TROUGH WAS OVER THE CANADIAN AND NORTHERN US
ROCKIES.
THE LEADING EDGE OF THE UPPER LEVEL SHORTWAVE IS PROGGED TO REACH
WESTERN NORTH DAKOTA BY EARLY AFTERNOON. THIS TIMING IS ABOUT 6
HOURS SLOWER THAN INDICATED BY THE PREVIOUS MODEL RUNS. THE
PRECIPITATION SHOULD BE IN THE FORM OF RAIN IN WESTERN NORTH
DAKOTA...AS TEMPERATURES RISE INTO THE 30S AND LOWER 40S.
THIS EVENING THE AREA OF PRECIPITATION SHOULD EXPAND INTO CENTRAL
NORTH DAKOTA. THE RAIN IN THE WEST IS EXPECTED TO CHANGEOVER TO SNOW
DURING THE EVENING. CENTRAL NORTH DAKOTA WILL LIKELY SEE A BRIEF
PERIOD OF LIGHT FREEZING RAIN OR SLEET THIS EVENING BEFORE CHANGING
TO ALL SNOW BY LATE EVENING. TOTAL SNOW ACCUMULATIONS TONIGHT SHOULD
RANGE FROM AROUND AN INCH IN THE WILLISTON AREA TO LESSER AMOUNTS
ELSEWHERE. SEE THE LONG TERM DISCUSSION FOR THE BULK OF THE SNOW
FROM THIS SYSTEM.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 414 AM CST SUN DEC 21 2014
SNOWFALL POTENTIAL MONDAY INTO TUESDAY IMPACTING EARLY CHRISTMAS
TRAVEL HIGHLIGHTS THE EXTENDED FORECAST.
THE 00 UTC AND INCOMING 06 UTC DETERMINISTIC AND ENSEMBLE GUIDANCE
CONTINUES TO SHOW MODEST SPREAD IN THE PROPAGATION OF THE UPPER
LEVEL LOW ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST MONDAY INTO
TUESDAY. THE BEST COMPROMISE APPEARS TO BE THE 03 UTC
SREF...FOLLOWED BY THE 00 UTC ECMWF. THEIR SOLUTIONS SUGGEST TWO
AREAS OF POTENTIALLY MODERATE SNOWFALL ACCUMULATIONS ACROSS
WESTERN AND CENTRAL NORTH DAKOTA DURING THE EVENT. THE FIRST IS WITH
A DEFORMATION ZONE ACROSS THE SOUTHWEST...AND THE SECOND ACROSS
THE JAMES RIVER VALLEY AND INTO FAR SOUTH CENTRAL NORTH DAKOTA
IN ASSOCIATION WITH THE TROWAL WITH THE UPPER LEVEL LOW. PER
COORDINATION WITH SURROUNDING OFFICES...WILL HIGHLIGHT THE EVENT
WITH AN SPS FOR...AND LET THE UPCOMING MODEL RUNS COME INTO A BIT
BETTER AGREEMENT IN THEIR MASS FIELDS. THEREAFTER...THE STORM
SYSTEM EXITS INTO THE GREAT LAKES FOR CHRISTMAS EVE...WITH
FAVORABLE TRAVEL CONDITIONS FOR NORTH DAKOTA INTO CHRISTMAS DAY.
TEMPERATURES WILL TREND BELOW AVERAGE LATE THIS COMING WEEK WITH A
MEAN LONG WAVE TROUGH ACROSS MUCH OF THE CONUS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1206 PM CST SUN DEC 21 2014
VLIFR-IFR CONDITIONS WILL PERSIST OVER EASTERN TERMINALS INCLUDING
KJMS THROUGH THE PERIOD...WITH LOW STRATUS AND FOG SPREADING
SLOWLY NORTH AND WEST AND POSSIBLY IMPACTING KBIS AND KMOT LATER
TODAY INTO THIS EVENING. LOW PRESSURE SYSTEM WILL MOVE EAST AND
BRING ANOTHER WARM FRONT EASTWARD ACROSS NORTH DAKOTA TODAY.
EXPECTING LIGHT RAIN AT KISN/KDIK AFTER 18Z WITH VFR CIGS...AND
BETWEEN 01Z-04Z EXPECT PRECIPITATION TO CHANGEOVER TO ALL SNOW.
PRECIPITATION AT KMOT/KBIS AFTER 00Z COULD BE IN THE FORM OF -FZRA
OR -IP BEFORE CHANGING OVER TO ALL SNOW BY 06Z. PREDOMINATELY
VLIFR-IFR CONDITIONS AREA WIDE TONIGHT INTO MONDAY MORNING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...JV
LONG TERM...AYD
AVIATION...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1049 AM CST SUN DEC 21 2014
.UPDATE...
ISSUED AT 1049 AM CST SUN DEC 21 2014
COMPLEX FORECAST OVER THE NEXT 24-36 HOURS. FOR THE MID MORNING
UPDATE MAIN CHANGE WAS TO INCREASE SKY COVER THROUGH THE DAY
ACROSS MY EAST ALONG WITH MENTIONING AREAS OF FOG. STRATUS
EXPANDING WEST AND NORTH ACROSS THE JAMES RIVER VALLEY WITH LOW
LEVEL MOISTURE ADVECTION WITH A SOUTH/SOUTHEAST WIND COMPONENT.
LAST FEW RUNS OF THE HRRR HANDLES THE STRATUS RATHER WELL SO WAS
UTILIZED. WILL NEED TO MONITOR VISIBILITIES IN CASE A DENSE FOG
ADVISORY IS NEEDED FOR THE JAMES VALLEY.
POPS ON TRACK WITH INCREASING CHANCES FOR PRECIPITATION IN THE
FORM OF RAIN SOUTHWEST AND A MIX NORTHWEST THIS AFTERNOON WITH THE
INCOMING STORM SYSTEM. FOR TONIGHT...CONTINUED THE TREND OF
STRATUS AND FOG EXPANDING WEST AND NORTH. ALSO...MODELS HINTING
RATHER STRONGLY AT LIGHT PRECIPITATION OVER MY EAST IN ADDITION TO
THE LIKELY/DEF POPS WEST. WE LOOK DRY ALOFT OVER MY EAST SO OPTED
TO MENTION FREEZING DRIZZLE WITH THE STRATUS AND FOG UNTIL WE
BECOME SATURATED OVERNIGHT.
UPDATE ISSUED AT 650 AM CST SUN DEC 21 2014
NO CHANGE IN FORECAST THINKING FOR THE REMAINDER OF THE DAY WITH
THE INCOMING 06 UTC GUIDANCE. THUS...BLENDED THE ONGOING FORECAST
TO OBSERVED TRENDS THROUGH 12 UTC.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 432 AM CST SUN DEC 21 2014
FIRST CONCERN IN THE SHORT TERM IS LINGERING FOG IN THE JAMESTOWN
AREA...AND THE POSSIBILITY OF FOG REFORMING IN THE TURTLE MOUNTAINS
TO THE MINOT AREA.
CURRENTLY A SURFACE LOW WAS CENTERED OVER SOUTHERN ALBERTA. A WARM
FRONT EXTENDED FROM THE LOW ACROSS SOUTHERN SASKATCHEWAN INTO
EASTERN NORTH DAKOTA...ASSOCIATED WITH THE LINGERING STRATUS AND
FOG. ANOTHER WARM FRONT EXTENDED FROM THE LOW SOUTHEASTWARD INTO
CENTRAL MONTANA AND EASTERN WYOMING. AT UPPER LEVELS...THE
ASSOCIATED SHORTWAVE TROUGH WAS OVER THE CANADIAN AND NORTHERN US
ROCKIES.
THE LEADING EDGE OF THE UPPER LEVEL SHORTWAVE IS PROGGED TO REACH
WESTERN NORTH DAKOTA BY EARLY AFTERNOON. THIS TIMING IS ABOUT 6
HOURS SLOWER THAN INDICATED BY THE PREVIOUS MODEL RUNS. THE
PRECIPITATION SHOULD BE IN THE FORM OF RAIN IN WESTERN NORTH
DAKOTA...AS TEMPERATURES RISE INTO THE 30S AND LOWER 40S.
THIS EVENING THE AREA OF PRECIPITATION SHOULD EXPAND INTO CENTRAL
NORTH DAKOTA. THE RAIN IN THE WEST IS EXPECTED TO CHANGEOVER TO SNOW
DURING THE EVENING. CENTRAL NORTH DAKOTA WILL LIKELY SEE A BRIEF
PERIOD OF LIGHT FREEZING RAIN OR SLEET THIS EVENING BEFORE CHANGING
TO ALL SNOW BY LATE EVENING. TOTAL SNOW ACCUMULATIONS TONIGHT SHOULD
RANGE FROM AROUND AN INCH IN THE WILLISTON AREA TO LESSER AMOUNTS
ELSEWHERE. SEE THE LONG TERM DISCUSSION FOR THE BULK OF THE SNOW
FROM THIS SYSTEM.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 414 AM CST SUN DEC 21 2014
SNOWFALL POTENTIAL MONDAY INTO TUESDAY IMPACTING EARLY CHRISTMAS
TRAVEL HIGHLIGHTS THE EXTENDED FORECAST.
THE 00 UTC AND INCOMING 06 UTC DETERMINISTIC AND ENSEMBLE GUIDANCE
CONTINUES TO SHOW MODEST SPREAD IN THE PROPAGATION OF THE UPPER
LEVEL LOW ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST MONDAY INTO
TUESDAY. THE BEST COMPROMISE APPEARS TO BE THE 03 UTC
SREF...FOLLOWED BY THE 00 UTC ECMWF. THEIR SOLUTIONS SUGGEST TWO
AREAS OF POTENTIALLY MODERATE SNOWFALL ACCUMULATIONS ACROSS
WESTERN AND CENTRAL NORTH DAKOTA DURING THE EVENT. THE FIRST IS WITH
A DEFORMATION ZONE ACROSS THE SOUTHWEST...AND THE SECOND ACROSS
THE JAMES RIVER VALLEY AND INTO FAR SOUTH CENTRAL NORTH DAKOTA
IN ASSOCIATION WITH THE TROWAL WITH THE UPPER LEVEL LOW. PER
COORDINATION WITH SURROUNDING OFFICES...WILL HIGHLIGHT THE EVENT
WITH AN SPS FOR...AND LET THE UPCOMING MODEL RUNS COME INTO A BIT
BETTER AGREEMENT IN THEIR MASS FIELDS. THEREAFTER...THE STORM
SYSTEM EXITS INTO THE GREAT LAKES FOR CHRISTMAS EVE...WITH
FAVORABLE TRAVEL CONDITIONS FOR NORTH DAKOTA INTO CHRISTMAS DAY.
TEMPERATURES WILL TREND BELOW AVERAGE LATE THIS COMING WEEK WITH A
MEAN LONG WAVE TROUGH ACROSS MUCH OF THE CONUS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 1049 AM CST SUN DEC 21 2014
VLIFR-IFR CONDITIONS WILL PERSIST OVER EASTERN TERMINALS INCLUDING
KJMS THROUGH THE PERIOD...WITH LOW STRATUS AND FOG SPREADING NORTH
AND WEST AND POSSIBLY IMPACTING KBIS AND KMOT LATER TODAY INTO
THIS EVENING. LOW PRESSURE SYSTEM WILL MOVE EAST AND BRING
ANOTHER WARM FRONT EASTWARD ACROSS NORTH DAKOTA TODAY. EXPECTING
LIGHT RAIN AT KISN/KDIK AFTER 18Z WITH VFR CIGS...AND BETWEEN
01Z-04Z EXPECT PRECIPITATION TO CHANGEOVER TO ALL SNOW.
PRECIPITATION AT KMOT/KBIS AFTER 00Z COULD BE IN THE FORM OF -FZRA
OR -IP BEFORE CHANGING OVER TO ALL SNOW BY 04Z. PREDOMINATELY VLIFR-
IFR CONDITIONS AREA WIDE TONIGHT INTO MONDAY MORNING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...JV
LONG TERM...AYD
AVIATION...JV
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
332 AM CST SUN DEC 21 2014
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 325 AM CST SUN DEC 21 2014
MAIN FORECAST CHALLENGE REVOLVES AROUND UPCOMING PRE CHRISTMAS
SNOW EVENT AND EXPECT SNOW AMOUNTS. CONFIDENCE RISING AS MODELS COMING
INTO BETTER AGREEMENT AND WILL USE MODEL BLEND AND NATIONAL
GUIDANCE FOR ANTICIPATED SNOW AMOUNTS.
AREA OF MAINLY -SN ASSOCIATED WITH CURRENT WAVE AND ZONE OF
ISENTROPIC LIFT WILL CONTINUE TO PROPAGATE EAST AND WILL MONITOR
FOR MORNING POPS. ONCE THIS MOVES THROUGH THIS AM REMAINDER OF THE
DAY SHOULD BE MAINLY DRY WITH PERSISTENT FOG AND LOW CIGS. WITH
SOUTHERLY FLOW...CONTINUED WARM ADVECTION AND WARMER START MOST OF
THE FA WILL BE A FEW DEGREES EITHER SIDE OF 32F.
WAVE WILL DROP INTO DEEPENING TROUGH TONIGHT CLOSING OFF OVER
SD/NE REGION BY MORNING. SURFACE INVERTED TROUGH FROM SD SURFACE
LOW GRADUALLY TAKES SHAPE ACROSS THE CENTRAL DAKOTAS. LOWERING
CONDENSATION PRESSURE DEFICITS AND ISENTROPIC LIFT CONFINED TO THE
SOUTHERN FA SO HAVE HIGHEST POPS THERE TOWARDS MORNING. CLOUDS WILL
HOLD TEMPERATURES UP OVERNIGHT.
STACKED LOW DRIFTS SLOWLY SE MONDAY ALLOWING SFC INVERTED TROUGH
TO SHIFT INTO THE FA. VIA OMEGA FIELDS AND 290K ISENTROPIC SURFACE
LIFT INCREASES DURING THE DAY AND RAISED POPS ACCORDINGLY. HAVE
HIGHEST POPS ASSOCIATED IN ZONE OF 850MB FRONTOGENETIC FORCING
ALTHOUGH AT THIS POINT BANDING SNOW POTENTIAL DOES NOT LOOK GREAT.
ALSO FROM THE 290K SURFACE FULL SATURATION LOOKS SPOTTY. BASED ON
SURFACE TEMPERATURES EXPECT CLOSE TO A 10:1 SNOW RATIO.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 325 AM CST SUN DEC 21 2014
LIFT LOOKS MAXIMIZED MONDAY NIGHT AND SHOULD BE THE FAVORED PERIOD
FOR ACCUMULATING SNOW. FORTUNATELY WIND DOES NOT LOOK TO BE A
SERIOUS ISSUE ALTHOUGH COULD SEE SOME DRIFTING IN OPEN AREAS.
LOW BEGINS TO FILL TUESDAY AND ISENTROPIC LIFT DIMINISHES DURING
THE DAY. STILL EXPECT -SN DURING DURING THE DAY BUT SHOULD
DIMINISH FROM WEST TO EAST DURING THE EVENING. COLD ADVECTION WEAK
AND MIXED LAYER VERY SHALLOW SO WINDS SHOULD BE MANAGEABLE.
CONSIDERING HEADLINES...BASED ON MODEL SOLUTIONS AND NATIONAL
GUIDANCE FEEL THIS WILL BE A FAIRLY EXTENDED PERIOD OF MAINLY
LIGHT SNOW. WITH WIND ALSO NOT APPEARING AS A SERIOUS ISSUE DO NOT
FEEL WATCH WARRANTED AT THIS POINT ALTHOUGH FUTURE ADVISORIES
LOOK LIKELY.
WEDNESDAY-SATURDAY...A BIT OF LIGHT SNOW COULD LINGER EAST OF THE
VALLEY ON WEDNESDAY AS THE LOW CONTINUES TO LIFT AWAY FROM THE AREA.
THEREAFTER HAVE MAINTAINED A PRIMARILY DRY FORECAST. THE 00Z
GFS/ECMWF INDICATE A MORE PROGRESSIVE PACIFIC SHORTWAVE TROUGH
CROSSING THE CENTRAL/NORTHERN PLAINS ON CHRISTMAS...WITH PRECIP
SUPPRESSED MAINLY SOUTH OF THE REGION. THERE WILL ALSO BE A FEW
SHORTWAVE TROUGHS DROPPING SOUTHEASTWARD IN AMPLIFYING NORTHWEST
FLOW ALOFT. WHILE ANY OF THESE MAY PRODUCE SOME LIGHT SNOW...THEY
WOULD BE RATHER MINOR. PERHAPS MORE IMPORTANTLY...THIS PATTERN WILL
ALLOW COLDER AIR TO FILTER SOUTHWARD FOR THE LATTER HALF OF THE
PERIOD. THE GFS/ECMWF BOTH INDICATE 850 MB TEMPS DROPPING TO -20C BY
NEXT SATURDAY...BRINGING TO AN END OUR RECENT STRING OF NEAR TO
ABOVE AVERAGE TEMPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1142 PM CST SAT DEC 20 2014
WILL KEEP IFR CIGS IN THRU THE TAF PERIOD. CLEARING IN CNTRL ND
JUST ABOUT DVL TO JMS AND HRRR INDICATES IT LIKELY NOT MAKING IT
FURTHER EAST. 925 MB WINDS ARE SOUTHWEST IN THAT AREA NOW AND TURN
MORE SOUTHERLY AGAIN BY 15Z SUN. DVL AIRPORT ONLY SPOT WHERE BRIEF
CLEARING MAY OCCUR...BUT ALSO ALONG THE CLEAR-CLOUD LINE THAT IS
WHERE THE FOG WAS THICKEST FRI NIGHT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...VOELKER
LONG TERM...MAKOWSKI/VOELKER
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1226 AM CST SUN DEC 21 2014
.UPDATE...
ISSUED AT 1226 AM CST SUN DEC 21 2014
MAIN CONCERN THIS UPDATE IS THE PRECIPITATION NORTH CENTRAL...FROM
BOTTINEAU AND THE TURTLE MOUNTAINS TO RUGBY. FORECAST SOUNDINGS
INDICATE THE PRECIPITATION SHOULD BE IN THE FORM OF FREEZING
RAIN...BUT MAY BE MIXING WITH OR CHANGING TO SNOW. THE AREA OF
PRECIPITATION WAS MOVING EAST AND SHOULD BE OUT OF THIS AREA BY
AROUND 2 AM CST.
THE LOW CLOUDS PERSISTED EAST OF MINOT AND JAMESTOWN AT
MIDNIGHT...BUT HRRR MODEL INDICATES LOW CLOUDS AND FOG RETURNING.
LESS CERTAIN FOR AS FAR SOUTHWEST AS BISMARCK.
UPDATE ISSUED AT 907 PM CST SAT DEC 20 2014
MAIN ISSUE THIS EVENING IS THE FREEZING RAIN AT NORTH CENTRAL. AS
THE PRECIP MOVES EAST INTO COLDER AIR IT IS EXPECTED TO CHANGE
OVER TO SNOW BASED ON MAT TEMP ALOFT FORECAST. WILL RAISE THE
CHANCE TO LIKELY CATEGORY OVER THE NORTH CENTRAL THIS EVENING. SO
FAR WILL HANDLE THIS LIGHT PRECIPITATION WITH SPECIAL WEATHER
STATEMENTS AND SOCIAL MEDIA POSTS.
UPDATE ISSUED AT 644 PM CST SAT DEC 20 2014
SEEING SOME VISIBILITY REDUCTION DUE TO SNOW/MIXED PRECIPITATION AT
TIOGA AND STANLEY WITH A NARROW BAND OF PRECIPITATION. REFINED THIS
AREA IN THE FORECAST ACROSS THE NORTH CENTRAL..AND RAISED POPS T
40 AS IT MOVES TOWARD MINOT. AM CONCERNED ABOUT THE STRATUS ACROSS
THE NORTH CENTRAL AND EAST CENTRAL. HRRR CONTINUES TO SHOW THE
STRATUS FILLING BACK IN ALTHOUGH THE SATELLITE TRENDS SHOW
CONTINUES MOVEMENT EAST OUT OF JAMESTOWN. WILL WATCH FOR THIS
TREND TO CHANGE.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 336 PM CST SAT DEC 20 2014
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE LINGERING
PRECIPITATION ASSOCIATED WITH A MID LEVEL WAVE MOVING EAST ACROSS
THE NORTHERN PLAINS TONIGHT...FOG REDEVELOPMENT TONIGHT EASTERN
HALF ALONG TO EAST OF HIGHWAY 83...THEN THE ONSET OF
PRECIPITATION WITH A STRONG STORM SYSTEM ON SUNDAY.
CURRENTLY...MID LEVEL S/WV IMPULSE OVER NORTHWESTERN NORTH DAKOTA
WITH AN ASSOCIATED SFC TROUGH/WARM FRONTAL BOUNDARY DRAPED NORTH
TO SOUTH-SOUTHEAST ACROSS THE CENTRAL DAKOTAS. BAND OF MID LEVEL
CLOUDS AND WEAK RADAR RETURNS ALONG THE BOUNDARY OVER MY EASTERN
COUNTIES AT THE MOMENT...WITH CLEARING SKIES WEST. THE EXCEPTION
IS OVER THE FAR NORTHWEST WHERE WRAP AROUND MOISTURE IS MOVING
INTO...WHERE WE EXPECT INCREASING CLOUDS AND A CHANCE FOR LIGHT
PRECIPITATION EITHER IN THE FORM OF RAIN OR A WINTRY MIX MID TO
LATE AFTERNOON.
WHILE THE BAND OF MID LEVEL CLOUDS IS EATING AWAY AT THE STRATUS
AND FOG CENTRAL INTO EAST...HIGH RES MODELS STRONGLY SUGGEST
REDEVELOPMENT INITIALLY WHERE IT IS AT NOW OVER MY EASTERN
COUNTIES...THEN EXPANDING WEST TO THE HIGHWAY 83 CORRIDOR. WRAP
AROUND PRECIPITATION WILL ALSO WORK ITS WAY EAST TONIGHT ACROSS
THE NORTH BEHIND THE AFOREMENTIONED MID LEVEL WAVE.
NEXT STORM SYSTEM ARRIVES SUNDAY. LEFT EXIT REGION OF A STRONG
UPPER LEVEL JET STREAK WILL PROMOTE LOW PRESSURE DEVELOPMENT OVER
NORTH CENTRAL MONTANA LATE TONIGHT INTO SUNDAY MORNING...WITH
THIS FEATURE THEN MOVING SOUTHEAST INTO EASTERN MONTANA DURING
SUNDAY AFTERNOON. FORCING WILL BE PLENTIFUL WITH INCREASING UPPER
LEVEL DIVERGENCE ON THE NOSE OF THE UPPER JET AND LOW LEVEL
THERMAL UPGLIDE AHEAD OF THE SFC LOW/WARM FRONT. ALREADY PLENTY
OF MOISTURE SO INCREASED POPS TO LIKELY/DEF WEST. THIS EVENT
CONTINUES INTO THE LONG TERM PERIOD SUNDAY NIGHT. SEE BELOW FOR
FURTHER DETAILS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 336 PM CST SAT DEC 20 2014
RAIN...FREEZING RAIN AND SNOW ARE LIKELY ACROSS THE REGION SUNDAY
INTO MONDAY.
FOR THE SUNDAY INTO MONDAY FORECAST WENT WITH A BLEND OF THE 12
UTC ECMWF/GFS/SREF AS THEY HAVE COME INTO BETTER AGREEMENT AND
DEPICT A REASONABLE SCENARIO. THE 12 UTC NAM APPEARED TO BE TOO
SLOW...TOO MOIST AND BROUGHT THE SURFACE LOW FURTHER NORTHEAST THAN THE
REST OF THE GUIDANCE. HOWEVER...IT IS IMPORTANT TO NOTE THAT THE
18 UTC NAM THAT JUST CAME IN HAS COME INTO BETTER AGREEMENT WITH
THE OTHER GUIDANCE AND NOW HAS THE LOW MOVING A BIT QUICKER AND
TRACKING ACROSS SOUTHWEST NORTH DAKOTA.
...THE MAIN FORECAST CHALLENGE AND UNCERTAINTIES WITH THIS SYSTEM ARE
PRECIP TRANSITION TIMES AND AMOUNTS...
RECENT MODEL TRENDS INDICATE WARMER AIR ALOFT WILL NOT BE AS
PRONOUNCED AND THEREFORE PRECIP TYPES SHOULD BE DETERMINED BY
SURFACE TEMPERATURE ALONE AND LIMITED TO RAIN/FREEZING RAIN/SNOW.
INITIALLY DRY AIR IS EXPECTED TO OCCUPY THE 850-700 MB LAYER. THIS
SHOULD LIMIT INITIAL PRECIP TO A LIGHT DRIZZLE...REGARDLESS OF SURFACE
TEMPERATURES...DUE TO LACK OF ICE (NO SNOW ALOFT). AS MOISTURE
FROM THE WEST MOVES IN AND COLD AIR ADVECTION ALOFT TAKES
HOLD...THE COLUMN SHOULD EVENTUALLY SATURATE AND SNOW WOULD LIKELY
FOLLOW. TEMPERATURES SUNDAY AFTERNOON/EVENING SHOULD BE WARM
ENOUGH ACROSS THE SOUTHWEST TO KEEP ALL PRECIPITATION LIQUID
THROUGH THE EARLY EVENING HOURS. THE INITIAL WAVE OF MOISTURE IS
EXPECTED TO ENTER WESTERN NORTH DAKOTA SHORTLY AFTER SUNSET. COLD
AIR SHOULD TAKE HOLD AFTER MIDNIGHT. IT IS AT THIS TIME WHEN A
TRANSITION TO SNOW IS EXPECTED. LIGHT SNOW IS THEN EXPECTED TO
FALL THROUGH THE DAY MONDAY...EVENTUALLY ACCUMULATING AROUND 3
INCHES ACROSS WESTERN NORTH DAKOTA AND THE JAMES RIVER VALLEY.
CENTRAL NORTH DAKOTA MAY EXPERIENCE A LOCAL MINIMUM OF SNOWFALL AS
THE LOW IS PROGGED TO PIVOT ALONG THE RED RIVER (KEEPING MOST OF
THE MOISTURE ALONG AND EAST OF THE JAMES VALLEY THROUGH THE DAY).
IN ADDITION TO SNOW...GUSTY WINDS AROUND 35 MPH MAY CREATE SOME
BLOWING SNOW...REDUCING VISIBILITY. THE STRONGEST WINDS ARE
EXPECTED ACROSS SOUTHWEST AND SOUTH CENTRAL NORTH
DAKOTA...COINCIDENT WITH A 10 MB/6 HOUR PRESSURE RISE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1226 AM CST SUN DEC 21 2014
AT MIDNIGHT CST...A WARM FRONT EXTENDED FROM LOW PRESSURE IN
ALBERTA/SASKATCHEWAN SOUTHEAST THROUGH EASTERN NORTH DAKOTA. THE
FRONT WILL BE THE FOCUS FOR A WINTRY MIX OF FREEZING RAIN AND SNOW
FROM BOTTINEAU AND THE TURTLE MOUNTAINS TO THE RUGBY AND HARVEY
AREAS THROUGH 2 AM CST. OTHERWISE AREAS OF FOG WILL AGAIN PLAGUE THE
REGION FROM A MINOT TO BISMARCK LINE. IFR CONDITIONS ARE EXPECTED TO
REDEVELOP EAST OF THIS LINE AND REMAIN VFR WEST. ANOTHER LOW
PRESSURE SYSTEM WILL APPROACH WESTERN NORTH DAKOTA SUNDAY AFTERNOON.
THIS COULD BRING A THREAT FOR FREEZING RAIN/SLEET/SNOW AT KISN AFTER
NOON CST. LEFT VCSH FOR NOW DUE TO UNCERTAINTY...BUT ADDED MENTION
OF -SN AFT 03Z. MORE CERTAIN ABOUT LIGHT RAIN MOVING INTO THE KDIK
AREA AFT 20Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...NH
LONG TERM...AJ
AVIATION...JV
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1146 PM CST SAT DEC 20 2014
.UPDATE...
ISSUED AT 1142 PM CST SAT DEC 20 2014
CONTINUED WITH LIKELY POPS SPREADING THRU NW MN NEXT FEW HOURS.
MAIN SNOW AREA NOW ROSEAU TO BAGLEY....JUST ENTERING BEMIDJI.
OTHERWISE MORE CONVECTIVE LOOKING SHOWERS AROUND GRAND FORKS AND
WEST SOUTH OF DVL FROM ACTIVITY THAT WAS EARLIER IN NW ND. THIS
SEEMS TO BE LIGHT SNOW AS WELL. OUTSIDE OF LIGHT SNOW
AREAS...GETTING THE LIGHT FOG/FREEZING DRIZZLE OR MIST. SO KEPT
THAT GOING AS WELL. TEMPS RISING A BIT WITH A GUSTY SOUTH WIND.
KEPT THEM STEADY TONIGHT INTO SUNDAY MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 310 PM CST SAT DEC 20 2014
FORECAST CHALLENGES WILL BE THE PCPN MOVING THROUGH THE FA TONIGHT
AND THEN THE POTENTIAL FOR A MON/TUE SNOWFALL. AS OF MID AFTERNOON
FOG STILL COVERED THE ENTIRE FA WITH A FEW PATCHES OF DENSE FOG
STILL UP AROUND CANDO/LANGDON. REGIONAL RADAR SHOWED A BAND OF
VERY LIGHT PCPN FROM BOTTINEAU DOWN THRU KJMS MOVING TO THE EAST
AT ABOUT 20KTS. KBIS DID GET A TRACE OF FZDZ AS THIS MOVED THRU
THEM AND NOW K06D IS REPORTING UNKNOWN PCPN. THINK THIS WILL
REMAIN PRETTY LIGHT FZDZ POSSIBLY MIXED WITH SOME LIGHT SNOW AS IT
MOVES THRU TONIGHT. AT THIS POINT THINK IT WILL STAY A THIN BAND
AS IT MOVES EAST THRU ND AND BE PRETTY MINIMAL. THERE IS ALSO SOME
COMMA HEAD PCPN MOVING INTO FAR NW ND NOW ASSOCIATED WITH THE MID
LEVEL WAVE. THEREFORE THERE COULD BE A LITTLE ADDITIONAL PCPN
ALONG THE CANADIAN BORDER LATER ASSOCIATED WITH THIS FEATURE.
MODELS SHOW THE THIN BAND POSSIBLY STRENGTHENING AS IT MOVES INTO
NW MN LATER THIS EVENING WITH A DUSTING TO AN INCH OF SNOW
POSSIBLE THERE. SINCE FOG STILL REMAINS OVER THE ENTIRE FA WILL
MENTION THAT INTO SUNDAY MORNING TOO. NOT SURE ABOUT DENSE FOG AND
WILL LET LATER SHIFTS MONITOR THAT. THERE IS SOME CLEARING OVER
SOUTHWEST ND WITH WEST/SW WINDS BUT DO NOT EXPECT WINDS TO SWITCH
TO THAT DIRECTION TO HELP SCOUR OUT THE FOG/STRATUS HERE. NOT
SURE IF FOG WILL SCOUR OUT ON SUNDAY EITHER SO BUMPED UP SKY
AMOUNTS THEN TOO.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 310 PM CST SAT DEC 20 2014
BY 00Z TUE THE SFC LOW SHOULD MOVE INTO THE ND/SD/MN BORDER REGION
SETTING UP A DECENT SNOW BAND OVER EASTERN ND/EXTREME NW MN...IN
AN INVERTED TROUGH. THIS MAINLY STAYS THE SET UP INTO MON NIGHT OR
EARLY TUE BEFORE SHIFTING OFF TO THE EAST. THIS IS USING THE 12Z
ECMWF/NAM WITH THE OTHER MODELS A LITTLE DIFFERENT. LOOKING AT
RAW SNOWFALL FROM THE ECMWF/NAM WOULD BRING UP TO 6 INCHES OVER
EASTERN ND/FAR NW MN. AT THIS TIME WPC SHOWS ABOUT 4-6 INCHES FROM
EAST CENTRAL ND INTO NW MN. STILL SOME UNCERTAINTY...BUT WILL
ISSUE AN SPS TO HIGHLIGHT THE TRANSITION BACK TO SNOWIER WEATHER.
FOR TUESDAY NIGHT THROUGH FRIDAY...MAIN CHALLENGE IS PCPN AMOUNTS
AND WINDS ON BACK SIDE OF DEPARTING LOW PRESSURE OVER THE GREAT
LAKES ON TUESDAY NIGHT INTO WEDNESDAY. MODELS DIFFERING SOMEWHAT IN
PLACEMENT OF PCPN BAND...BUT FOR THE MOST PART PUTTING IT EAST OF
THE RED RIVER. LOOKING FOR PCPN TO BE IN THE FORM OF SNOW AS MAX
TEMPS ALOFT RANGE FROM -4C TO -7C...AND COLDER AIR WILL CONTINUE TO
WRAP BEHIND THE SYSTEM. WINDS SHOULD BEGIN TO DECREASE AS PRESSURE
GRADIENT WEAKENS...AND SFC HIGH PRESSURE TAKES OVER BY CHRISTMAS DAY
BRINGING DRIER CONDITIONS. OTHERWISE...EXPECT COOLING TEMPERATURES
AND A SLIGHT CHANCE FOR PCPN NEAR THE END OF THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1142 PM CST SAT DEC 20 2014
WILL KEEP IFR CIGS IN THRU THE TAF PERIOD. CLEARING IN CNTRL ND
JUST ABOUT DVL TO JMS AND HRRR INDICATES IT LIKELY NOT MAKING IT
FURTHER EAST. 925 MB WINDS ARE SOUTHWEST IN THAT AREA NOW AND TURN
MORE SOUTHERLY AGAIN BY 15Z SUN. DVL AIRPORT ONLY SPOT WHERE BRIEF
CLEARING MAY OCCUR...BUT ALSO ALONG THE CLEAR-CLOUD LINE THAT IS
WHERE THE FOG WAS THICKEST FRI NIGHT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...GODON
LONG TERM...GODON/HOPKINS
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
306 PM EST SUN DEC 21 2014
.SYNOPSIS...
WEAK HIGH PRESSURE EXITS THIS EVENING. SYSTEM CLIPS THE MOUNTAINS
MONDAY. STRONG LOW PRESSURE SYSTEM LIFTS NORTHEAST ACROSS THE OHIO
VALLEY THROUGH CHRISTMAS EVE.
&&
.NEAR TERM /THROUGH MONDAY/...
HIGH PRESSURE AND LIGHT E FLOW HAD MANAGED TO ERADICATE THE STRATUS
ALONG AND E OF THE OHIO RIVER TODAY. THIS HAS ALLOWED FOR DAYTIME
HEATING BUT WILL ALSO ALLOW FOR RADIATIVE COOLING THIS EVENING.
A WARM WAVE RIDES UP THE SE COAST LATE TONIGHT AND MON. THE
QUESTION IS TO WHAT DEGREE THIS FLAT WAVE CAN THROUGH PRECIPITATION
BACK INTO THE FCST AREA...AND WHEN WILL SUCH PRECIPITATION REACH THE
GROUND GIVEN THE DRY MID LEVEL AIR TO START OUT WITH.
MOST OF THE GUIDANCE SUGGESTS TEMPERATURES NEAR OR JUST BELOW
FREEZING IN THE NRN WV MOUNTAINS...MAINLY ON THE HIGHER PEAKS AND
DOWN THE ERN SLOPES INTO THE GREENBRIER VALLEY. MODELS DEPICT A
WARM LAYER ALOFT WITH TEMPERATURES 1-2C IN THE H925-H85 LAYER. THIS
SUGGESTS MELTING OF SNOW WHICH MEANS THERE COULD BE SLEET AND SNOW
MIXED IN WITH ANY FREEZING RAIN. TEMPERATURES IN CLOUD SUPPORTIVE
OF ICE CRYSTALS ARE LOST EARLY ON AS THE MOIST LAYER BECOMES MORE
SHALLOW. THIS WOULD TEND THE PRECIPITATION BACK TOWARD FREEZING
RAIN OR FREEZING DRIZZLE.
THIS LEAVES THE TIMING OF THE ARRIVAL OF PRECIPITATION CRUCIAL AS
TEMPERATURES SLOWLY CLIMB ABOVE FREEZING IN THE GREENBRIER VALLEY.
CURRENT GRID DEPICTION IS FOR POPS CLIMBING ABOVE 50 YIELDING
MEASURABLE QPF AS TEMPERATURES CLIMB. THIS LIMITS ICE ACCRETION TO
AT MOST A HUNDREDTH AND NOT VERY WIDESPREAD. THE SREF DOES
INTERSECT HIGH POPS WITH POCKETS OF HIGH PROBABILITIES FOR SFC
TEMPERATURES AT OR BELOW FREEZING MON MIDDAY INTO THE AFTERNOON.
COORD WITH WPC/WWD-PBZ-LWX-RNK ON ISSUANCE ADV FOR FREEZING RAIN
POCAHONTAS COUNTY 11-17Z.
THE REMAINDER OF THE FCST AREA SEES A RETURN OF CLOUD COVER
TONIGHT...SETTING THE STAGE FOR ANOTHER GREY DECEMBER DAY...ALTHOUGH
THE CLOUDS DO DECREASE BEHIND THE SYSTEM MON AFTERNOON.
USED NEAR TERM...IN PARTICULARLY THE WRFNMM...RUC AND THE HRRR FOR
TEMPERATURES TONIGHT AND NAM-BASED VALUES FOR THOSE ON MON...WHICH
SHOULD FEATURE A MILDER AFTERNOON.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
5H TROUGH TO DIG OVER THE MIDWEST WITH SEVERAL WAVES RIDING NWD
ALONG THE COAST OF SE US. THIS LEAVES OUR CWA IN THE WARM SECTOR
OF BAROCLINIC FORCING THAT WILL BE TAKING PLACE IN VARIOUS PHASES
THROUGHOUT THE PERIOD. FIRST WEAKER WAVE DEFTLY EXITS TO THE EAST
BY TUESDAY MORNING AND ONLY BROUGHT ISOLD AND LOW CHANCE POPS TO
THE EASTERN MOUNTAINS. WAA WILL BE FULL SWING UNDER SOUTH TO
SOUTHWEST FLOW AND CHANCES FOR ANY PRECIPITATION OF THE FROZEN
VARIETY WILL BE NIL.
A SECOND STRONGER WAVE WILL PUSH NORTH TUESDAY NIGHT AND
WEDNESDAY. MODELS STILL SHOW POOR PHASING BETWEEN NORTHERN AND
SOUTH STREAM SYSTEMS WITH MAIN SFC LOW DEVELOPMENT OCCURRING NORTH
OF THE GREAT LAKES. THIS DELAYS FROPA AND ONSET OF CAA AND PLACES
CWA SQUARELY IN THE WARM SECTOR THROUGH WEDNESDAY. FRONT WILL
FINIALLY PUSH THROUGH WEDNESDAY NIGHT WITH PRECIPITATION COMING TO
AN END...MOSTLY BEFORE THE COLDER AIR ON BACKSIDE IS ABLE TO MOVE
IN. THUS...ONLY HAVE VERY LIGHT SNOW AMOUNTS FIGURED FOR THE
MOUNTAINS IN NORTHEASTERN COUNTIES.
USED MAINLY SREF FOR TIMING ONSET OF PRECIP DEVELOPMENT. FOR
TEMPS...USED BC GRIDS WITH A BLEND TOWARD INHERITED FORECAST
TEMPS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
COLD FRONT TO THE EAST OF THE CWA AT THE BEGINNING OF THE
PERIOD...WITH A GRADUAL CHANGE OVER TO SNOW FOR CHRISTMAS EVE NIGHT
AND CHRISTMAS DAY. AT THIS POINT...REALLY NOT EXPECTING MUCH IN
TERMS OF SNOWFALL ACCUMULATIONS. WINDS HOWEVER ON THURSDAY ARE STILL
EXPECTED TO BE GUSTY POST FRONTAL.
AREA DRIES OUT THURSDAY EVENING AS THE LOW PULLS OFF TO THE
NORTHEAST. HIGH PRESSURE THEN BRIEFLY BUILDS IN FOR A BREAK IN
PRECIPITATION. ANOTHER COLD FRONT WILL DROP ACROSS THE AREA OVER THE
WEEKEND...CREATING A CHANCE FOR LIGHT SNOW SHOWERS...AND WILL USHER
IN MUCH COLDER AIR INTO THE REGION. TRENDED TEMPERATURES NEXT
WEEKEND DOWN FROM PREVIOUS FORECAST.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
LIGHT E FLOW ON S SIDE OF HIGH PRESSURE HAD FINALLY ERADICATED THE
MVFR TO HIGH IFR STRATOCU...WITH ALL SITES VFR TO START THE FCST.
THIS WILL HOLD THROUGH SUNSET.
A WEAK WAVE OF LOW PRESSURE MOVES UP ALONG THE SE COAST OVERNIGHT
TONIGHT AND MON. THIS WILL SPILL CLOUDS BACK INTO THE AREA
OVERNIGHT...WITH RAIN LIKELY IN THE MOUNTAINS...MAINLY ON THE
EASTERN SLOPES...WHERE SNOW...SLEET AND FREEZING RAIN ARE LIKELY TO
BE MIXED IN THROUGH THE MORNING HOURS.
MVFR TO HIGH IFR STRATOCU SHOULD RETURN TO BKW TONIGHT...WITH A MORE
WIDESPREAD MVFR DECK DEVELOPING BY MON MORNING. CLOUD HEIGHTS
SHOULD INCREASE MON AFTERNOON AS CLOUD AMOUNT LOWERS.
LIGHT AND VARIABLE TO E SFC FLOW WILL BECOME LIGHT SE TONIGHT AND
REMAIN SO ON MON. SE WINDS WILL BECOME A BIT GUSTY ON THE RIDGES
INCLUDING BKW OVERNIGHT INTO MON. FLOW ALOFT WILL REMAIN LIGHT S TO
SW.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING AND LOCATION OF A MVFR STRATUS DECK
COULD VARY CONSIDERABLY OVERNIGHT INTO MON.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
CRW CONSISTENCY M M H H H H H H H H H H
HTS CONSISTENCY M M H H H H H H H H H H
BKW CONSISTENCY H H H M M M M M L L L L
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY M M M M M H H H H H H H
CKB CONSISTENCY M M M M H H H H H H H H
AFTER 18Z MONDAY...
IFR POSSIBLE IN MOUNTAINS INTO MON AFTERNOON IN A WINTRY MIX. IFR
POSSIBLE IN RAIN TUE NT INTO WED...CHANGING TO SNOW SHOWERS WED
NT...AS AN INTENSE LOW PRESSURE CENTER PASSES.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FREEZING RAIN ADVISORY FROM 6 AM TO NOON EST MONDAY FOR WVZ046.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/RPY/SL/30
NEAR TERM...TRM
SHORT TERM...KMC
LONG TERM...SL
AVIATION...TRM
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
158 PM EST SUN DEC 21 2014
.SYNOPSIS...
WEAK HIGH PRESSURE EXITS THIS EVENING. SYSTEM CLIPS THE MOUNTAINS
MONDAY. STRONG LOW PRESSURE SYSTEM LIFTS NORTHEAST ACROSS THE OHIO
VALLEY THROUGH CHRISTMAS EVE.
&&
.NEAR TERM /THROUGH MONDAY/...
HIGH PRESSURE AND LIGHT E FLOW HAD MANAGED TO ERADICATE THE STRATUS
ALONG AND E OF THE OHIO RIVER TODAY. THIS HAS ALLOWED FOR DAYTIME
HEATING BUT WILL ALSO ALLOW FOR RADIATIVE COOLING THIS EVENING.
A WARM WAVE RIDES UP THE SE COAST LATE TONIGHT AND MON. THE
QUESTION IS TO WHAT DEGREE THIS FLAT WAVE CAN THROUGH PRECIPITATION
BACK INTO THE FCST AREA...AND WHEN WILL SUCH PRECIPITATION REACH THE
GROUND GIVEN THE DRY MID LEVEL AIR TO START OUT WITH.
MOST OF THE GUIDANCE SUGGESTS TEMPERATURES NEAR OR JUST BELOW
FREEZING IN THE NRN WV MOUNTAINS...MAINLY ON THE HIGHER PEAKS AND
DOWN THE ERN SLOPES INTO THE GREENBRIER VALLEY. MODELS DEPICT A
WARM LAYER ALOFT WITH TEMPERATURES 1-2C IN THE H925-H85 LAYER. THIS
SUGGESTS MELTING OF SNOW WHICH MEANS THERE COULD BE SLEET AND SNOW
MIXED IN WITH ANY FREEZING RAIN. TEMPERATURES IN CLOUD SUPPORTIVE
OF ICE CRYSTALS ARE LOST EARLY ON AS THE MOIST LAYER BECOMES MORE
SHALLOW. THIS WOULD TEND THE PRECIPITATION BACK TOWARD FREEZING
RAIN OR FREEZING DRIZZLE.
THIS LEAVES THE TIMING OF THE ARRIVAL OF PRECIPITATION CRUCIAL AS
TEMPERATURES SLOWLY CLIMB ABOVE FREEZING IN THE GREENBRIER VALLEY.
CURRENT GRID DEPICTION IS FOR POPS CLIMBING ABOVE 50 YIELDING
MEASURABLE QPF AS TEMPERATURES CLIMB. THIS LIMITS ICE ACCRETION TO
AT MOST A HUNDREDTH AND NOT VERY WIDESPREAD. THE SREF DOES
INTERSECT HIGH POPS WITH POCKETS OF HIGH PROBABILITIES FOR SFC
TEMPERATURES AT OR BELOW FREEZING MON MIDDAY INTO THE AFTERNOON.
COORD WITH WPC/WWD-PBZ-LWX-RNK ON ISSUANCE ADV FOR FREEZING RAIN
POCAHONTAS COUNTY 11-17Z.
THE REMAINDER OF THE FCST AREA SEES A RETURN OF CLOUD COVER
TONIGHT...SETTING THE STAGE FOR ANOTHER GREY DECEMBER DAY...ALTHOUGH
THE CLOUDS DO DECREASE BEHIND THE SYSTEM MON AFTERNOON.
USED NEAR TERM...IN PARTICULARLY THE WRFNMM...RUC AND THE HRRR FOR
TEMPERATURES TONIGHT AND NAM-BASED VALUES FOR THOSE ON MON...WHICH
SHOULD FEATURE A MILDER AFTERNOON.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
PESKY MOISTURE FROM WEAK SURFACE LOW ALONG THE E COAST AS WELL AS
WAA WILL COMBINE FOR LIGHT PRECIP MOVING UP THE MOUNTAINS MONDAY
MORNING. THERMAL PROFILES CONTINUE TO INDICATE A BRIEF ONSET OF
FZRA WITH PSBL SLEET...BEFORE CHANGING OVER TO LIQUID BY MIDDAY
AND PULLING OUT IN THE AFTERNOON. TEMPS SHOULD RECOVER BEHIND THIS
SYSTEM FOR THE AFTERNOON WITH AID OF DEVELOPING SE DOWN SLOPE FLOW.
SOME PEAKS OF SUN IS PSBL S OF I64 LATE IN THE DAY. AS THE SE FLOW
INCREASES MONDAY NIGHT AND WAA ALOFT CONTINUES...THINK THE RIDGES
WILL SEE RISING TEMPS OVERNIGHT AMID INCREASING CLOUDS OVER THE AREA.
THERE HAS BEEN A NOTICEABLE TREND IN THE MODELS REGARDING THE
MIDWEEK SYSTEM. MOST DELAY PHASING AND RAPID PRESSURE DROPS UNTIL
INTO CANADA. WHAT THIS DOES IS TO SLOW THE FRONT/NOW ABOUT 6 HRS/ AND
LESSEN THE MAGNITUDE OF SENSIBLE WX EFFECTS FROM THIS
SYSTEM...INCLUDING POST FRONTAL CAA...SURFACE TEMPS...AND EXTENT
AND DURATION OF SHSN BEHIND THE FRONT. HAVE MODIFIED THE GRIDS TO
INCORPORATE THIS TREND IN THE MODEL SUITE AND DELAYED CHANGEOVER
TO SHSN.
WITH THE SLOWER TIMING OF THE FRONT...LOOKS LIKE CHRISTMAS EVE
MAY BE JUST AS WARM AS TUESDAY WITH LOW TO MID 60S POSSIBLE BOTH
DAYS. STILL THINKING TUESDAY THE DAYLIGHT HRS ON TUESDAY IS DRY E
OF THE OH RIVER WITH SHRA MOVING INTO SE OH AND NE KY IN THE
AFTERNOON WHICH THEN OVERSPREADS REMAINDER OF AREA TUESDAY NIGHT
AND WEDNESDAY. IT WILL BE A MILD TUESDAY NIGHT DESPITE THE SHRA AS
LOW LEVEL SE FLOW REACHES ITS MAXIMUM. WHAT STILL LOOKS LIKELY ARE
THE STRONG GUSTY WINDS CHRISTMAS EVE NIGHT AND CHRISTMAS DAY
ITSELF...WITH 30 KTS PSBL ESPECIALLY ACROSS N ZONES AND IN THE
MOUNTAINS WHERE EVEN HIGHER GUSTS ARE EXPECTED.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
COLD FRONT TO THE EAST OF THE CWA AT THE BEGINNING OF THE
PERIOD...WITH A GRADUAL CHANGE OVER TO SNOW FOR CHRISTMAS EVE NIGHT
AND CHRISTMAS DAY. AT THIS POINT...REALLY NOT EXPECTING MUCH IN
TERMS OF SNOWFALL ACCUMULATIONS. WINDS HOWEVER ON THURSDAY ARE STILL
EXPECTED TO BE GUSTY POST FRONTAL.
AREA DRIES OUT THURSDAY EVENING AS THE LOW PULLS OFF TO THE
NORTHEAST. HIGH PRESSURE THEN BRIEFLY BUILDS IN FOR A BREAK IN
PRECIPITATION. ANOTHER COLD FRONT WILL DROP ACROSS THE AREA OVER THE
WEEKEND...CREATING A CHANCE FOR LIGHT SNOW SHOWERS...AND WILL USHER
IN MUCH COLDER AIR INTO THE REGION. TRENDED TEMPERATURES NEXT
WEEKEND DOWN FROM PREVIOUS FORECAST.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
LIGHT E FLOW ON S SIDE OF HIGH PRESSURE HAD FINALLY ERADICATED THE
MVFR TO HIGH IFR STRATOCU...WITH ALL SITES VFR TO START THE FCST.
THIS WILL HOLD THROUGH SUNSET.
A WEAK WAVE OF LOW PRESSURE MOVES UP ALONG THE SE COAST OVERNIGHT
TONIGHT AND MON. THIS WILL SPILL CLOUDS BACK INTO THE AREA
OVERNIGHT...WITH RAIN LIKELY IN THE MOUNTAINS...MAINLY ON THE
EASTERN SLOPES...WHERE SNOW...SLEET AND FREEZING RAIN ARE LIKELY TO
BE MIXED IN THROUGH THE MORNING HOURS.
MVFR TO HIGH IFR STRATOCU SHOULD RETURN TO BKW TONIGHT...WITH A MORE
WIDESPREAD MVFR DECK DEVELOPING BY MON MORNING. CLOUD HEIGHTS
SHOULD INCREASE MON AFTERNOON AS CLOUD AMOUNT LOWERS.
LIGHT AND VARIABLE TO E SFC FLOW WILL BECOME LIGHT SE TONIGHT AND
REMAIN SO ON MON. SE WINDS WILL BECOME A BIT GUSTY ON THE RIDGES
INCLUDING BKW OVERNIGHT INTO MON. FLOW ALOFT WILL REMAIN LIGHT S TO
SW.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING AND LOCATION OF A MVFR STRATUS DECK
COULD VARY CONSIDERABLY OVERNIGHT INTO MON.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00
CRW CONSISTENCY M M M M H H H H H H H H
HTS CONSISTENCY H M M M H H H H H H H H
BKW CONSISTENCY H H H H H M M M M M L L
EKN CONSISTENCY M M H H H H H H H H H H
PKB CONSISTENCY M M M M M M M H H H H H
CKB CONSISTENCY M M M M M M H H H H H H
AFTER 18Z MONDAY...
IFR POSSIBLE IN MOUNTAINS INTO MON AFTERNOON IN A WINTRY MIX. IFR
POSSIBLE IN RAIN TUE NT INTO WED...CHANGING TO SNOW SHOWERS WED
NT...AS AN INTENSE LOW PRESSURE CENTER PASSES.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FREEZING RAIN ADVISORY FROM 6 AM TO NOON EST MONDAY FOR WVZ046.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/RPY/SL/30
NEAR TERM...TRM
SHORT TERM...30
LONG TERM...SL
AVIATION...TRM
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
145 PM EST SUN DEC 21 2014
.SYNOPSIS...
WEAK HIGH PRESSURE EXITS THIS EVENING. SYSTEM CLIPS THE MOUNTAINS
MONDAY. STRONG LOW PRESSURE SYSTEM LIFTS NORTHEAST ACROSS THE OHIO
VALLEY THROUGH CHRISTMAS EVE.
&&
.NEAR TERM /THROUGH MONDAY/...
HIGH PRESSURE AND LIGHT E FLOW HAD MANAGED TO ERADICATE THE STRATUS
ALONG AND E OF THE OHIO RIVER TODAY. THIS HAS ALLOWED FOR DAYTIME
HEATING BUT WILL ALSO ALLOW FOR RADIATIVE COOLING THIS EVENING.
A WARM WAVE RIDES UP THE SE COAST LATE TONIGHT AND MON. THE
QUESTION IS TO WHAT DEGREE THIS FLAT WAVE CAN THROUGH PRECIPITATION
BACK INTO THE FCST AREA...AND WHEN WILL SUCH PRECIPITATION REACH THE
GROUND GIVEN THE DRY MID LEVEL AIR TO START OUT WITH.
MOST OF THE GUIDANCE SUGGESTS TEMPERATURES NEAR OR JUST BELOW
FREEZING IN THE NRN WV MOUNTAINS...MAINLY ON THE HIGHER PEAKS AND
DOWN THE ERN SLOPES INTO THE GREENBRIER VALLEY. MODELS DEPICT A
WARM LAYER ALOFT WITH TEMPERATURES 1-2C IN THE H925-H85 LAYER. THIS
SUGGESTS MELTING OF SNOW WHICH MEANS THERE COULD BE SLEET AND SNOW
MIXED IN WITH ANY FREEZING RAIN. TEMPERATURES IN CLOUD SUPPORTIVE
OF ICE CRYSTALS ARE LOST EARLY ON AS THE MOIST LAYER BECOMES MORE
SHALLOW. THIS WOULD TEND THE PRECIPITATION BACK TOWARD FREEZING
RAIN OR FREEZING DRIZZLE.
THIS LEAVES THE TIMING OF THE ARRIVAL OF PRECIPITATION CRUCIAL AS
TEMPERATURES SLOWLY CLIMB ABOVE FREEZING IN THE GREENBRIER VALLEY.
CURRENT GRID DEPICTION IS FOR POPS CLIMBING ABOVE 50 YIELDING
MEASURABLE QPF AS TEMPERATURES CLIMB. THIS LIMITS ICE ACCRETION TO
AT MOST A HUNDREDTH AND NOT VERY WIDESPREAD. THE SREF DOES
INTERSECT HIGH POPS WITH POCKETS OF HIGH PROBABILITIES FOR SFC
TEMPERATURES AT OR BELOW FREEZING MON MIDDAY INTO THE AFTERNOON.
COORD WITH WPC/WWD-PBZ-LWX-RNK ON ISSUANCE ADV FOR FREEZING RAIN
POCAHONTAS COUNTY 11-17Z.
THE REMAINDER OF THE FCST AREA SEES A RETURN OF CLOUD COVER
TONIGHT...SETTING THE STAGE FOR ANOTHER GREY DECEMBER DAY...ALTHOUGH
THE CLOUDS DO DECREASE BEHIND THE SYSTEM MON AFTERNOON.
USED NEAR TERM...IN PARTICULARLY THE WRFNMM...RUC AND THE HRRR FOR
TEMPERATURES TONIGHT AND NAM-BASED VALUES FOR THOSE ON MON...WHICH
SHOULD FEATURE A MILDER AFTERNOON.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
PESKY MOISTURE FROM WEAK SURFACE LOW ALONG THE E COAST AS WELL AS
WAA WILL COMBINE FOR LIGHT PRECIP MOVING UP THE MOUNTAINS MONDAY
MORNING. THERMAL PROFILES CONTINUE TO INDICATE A BRIEF ONSET OF
FZRA WITH PSBL SLEET...BEFORE CHANGING OVER TO LIQUID BY MIDDAY
AND PULLING OUT IN THE AFTERNOON. TEMPS SHOULD RECOVER BEHIND THIS
SYSTEM FOR THE AFTERNOON WITH AID OF DEVELOPING SE DOWN SLOPE FLOW.
SOME PEAKS OF SUN IS PSBL S OF I64 LATE IN THE DAY. AS THE SE FLOW
INCREASES MONDAY NIGHT AND WAA ALOFT CONTINUES...THINK THE RIDGES
WILL SEE RISING TEMPS OVERNIGHT AMID INCREASING CLOUDS OVER THE AREA.
THERE HAS BEEN A NOTICEABLE TREND IN THE MODELS REGARDING THE
MIDWEEK SYSTEM. MOST DELAY PHASING AND RAPID PRESSURE DROPS UNTIL
INTO CANADA. WHAT THIS DOES IS TO SLOW THE FRONT/NOW ABOUT 6 HRS/ AND
LESSEN THE MAGNITUDE OF SENSIBLE WX EFFECTS FROM THIS
SYSTEM...INCLUDING POST FRONTAL CAA...SURFACE TEMPS...AND EXTENT
AND DURATION OF SHSN BEHIND THE FRONT. HAVE MODIFIED THE GRIDS TO
INCORPORATE THIS TREND IN THE MODEL SUITE AND DELAYED CHANGEOVER
TO SHSN.
WITH THE SLOWER TIMING OF THE FRONT...LOOKS LIKE CHRISTMAS EVE
MAY BE JUST AS WARM AS TUESDAY WITH LOW TO MID 60S POSSIBLE BOTH
DAYS. STILL THINKING TUESDAY THE DAYLIGHT HRS ON TUESDAY IS DRY E
OF THE OH RIVER WITH SHRA MOVING INTO SE OH AND NE KY IN THE
AFTERNOON WHICH THEN OVERSPREADS REMAINDER OF AREA TUESDAY NIGHT
AND WEDNESDAY. IT WILL BE A MILD TUESDAY NIGHT DESPITE THE SHRA AS
LOW LEVEL SE FLOW REACHES ITS MAXIMUM. WHAT STILL LOOKS LIKELY ARE
THE STRONG GUSTY WINDS CHRISTMAS EVE NIGHT AND CHRISTMAS DAY
ITSELF...WITH 30 KTS PSBL ESPECIALLY ACROSS N ZONES AND IN THE
MOUNTAINS WHERE EVEN HIGHER GUSTS ARE EXPECTED.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
ACTIVE WEATHER PATTERN CONTINUES IN THE LONG TERM PERIOD...WITH A
DEEPENING UPPER TROUGH ACROSS THE CENTRAL PLAINS AT THE BEGINNING OF
PERIOD...WITH A SURFACE LOW MOVING NORTHEAST OUT OF THE GULF STATES
TOWARDS THE REGION. STRONG SOUTHERLY WINDS WILL DEVELOP OUT AHEAD OF
THE SYSTEM...WITH GOOD MOISTURE TRANSPORT INTO THE AREA AS A RESULT.
THIS IS A STRONG SYSTEM...WITH STRONG PRESSURE FALLS/BOMBOGENESIS AS
THE LOW MOVES TOWARDS THE REGION. COLD FRONT STILL PROGGED TO MOVE
THROUGH THE AREA WEDNESDAY...WITH FALLING TEMPERATURES...STRONG
GUSTY WINDS ALONG AND BEHIND THE FRONT DUE TO TIGHT PRESSURE
GRADIENT...AND POTENTIAL FOR STRONG WINDS ALOFT TO MIX DOWN...AND
EVEN A SLIGHT CHANCE FOR THUNDER...MAINLY ACROSS THE WEST...AS THE
FRONT MOVES INTO THE REGION. STARTING TO LOOK MORE AND MORE LIKE
WINTER PRECIPITATION WILL NOT BE A HUGE HAZARD WITH THIS
SYSTEM...DUE TO THE OVERALL SPEED...AND THE FACT THAT BY THE TIME
ENOUGH COLD AIR IS IN PLACE...BULK OF MOISTURE SHOULD HAVE EXITED.
IN ADDITION...STILL QUITE A BIT OF UNCERTAINTY AS TO HOW MUCH WILL
ACTUALLY BE ABLE TO STICK TO THE GROUND IF GROUND TEMPERATURES ARE
TOO WARM AS TEMPERATURES WILL RISE INTO THE 50S OUT AHEAD OF THE
SYSTEM. HOWEVER...WILL STILL SEE A CHANGE OVER TO SNOW WEDNESDAY
NIGHT INTO THURSDAY...ALONG WITH FALLING TEMPERATURES. WILL CONTINUE
TO MAINTAIN HWO.
ON THURSDAY...UPPER LOW LIFTS NORTH ACROSS CANADA...BECOMING NEARLY
STACKED WITH SURFACE LOW. STILL A CHANCE FOR SOME LIGHT SNOW SHOWER
ACTIVITY ON THURSDAY...BUT WILL GRADUALLY SEE A DRYING TREND FROM
SOUTH TO NORTH AS THE SYSTEM PULLS AWAY.
ANOTHER FRONT APPROACHES LATE IN THE EXTENDED.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
LIGHT E FLOW ON S SIDE OF HIGH PRESSURE HAD FINALLY ERADICATED THE
MVFR TO HIGH IFR STRATOCU...WITH ALL SITES VFR TO START THE FCST.
THIS WILL HOLD THROUGH SUNSET.
A WEAK WAVE OF LOW PRESSURE MOVES UP ALONG THE SE COAST OVERNIGHT
TONIGHT AND MON. THIS WILL SPILL CLOUDS BACK INTO THE AREA
OVERNIGHT...WITH RAIN LIKELY IN THE MOUNTAINS...MAINLY ON THE
EASTERN SLOPES...WHERE SNOW...SLEET AND FREEZING RAIN ARE LIKELY TO
BE MIXED IN THROUGH THE MORNING HOURS.
MVFR TO HIGH IFR STRATOCU SHOULD RETURN TO BKW TONIGHT...WITH A MORE
WIDESPREAD MVFR DECK DEVELOPING BY MON MORNING. CLOUD HEIGHTS
SHOULD INCREASE MON AFTERNOON AS CLOUD AMOUNT LOWERS.
LIGHT AND VARIABLE TO E SFC FLOW WILL BECOME LIGHT SE TONIGHT AND
REMAIN SO ON MON. SE WINDS WILL BECOME A BIT GUSTY ON THE RIDGES
INCLUDING BKW OVERNIGHT INTO MON. FLOW ALOFT WILL REMAIN LIGHT S TO
SW.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING AND LOCATION OF A MVFR STRATUS DECK
COULD VARY CONSIDERABLY OVERNIGHT INTO MON.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00
CRW CONSISTENCY M M M M H H H H H H H H
HTS CONSISTENCY H M M M H H H H H H H H
BKW CONSISTENCY H H H H H M M M M M L L
EKN CONSISTENCY M M H H H H H H H H H H
PKB CONSISTENCY M M M M M M M H H H H H
CKB CONSISTENCY M M M M M M H H H H H H
AFTER 18Z MONDAY...
IFR POSSIBLE IN MOUNTAINS INTO MON AFTERNOON IN A WINTRY MIX. IFR
POSSIBLE IN RAIN TUE NT INTO WED...CHANGING TO SNOW SHOWERS WED
NT...AS AN INTENSE LOW PRESSURE CENTER PASSES.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FREEZING RAIN ADVISORY FROM 6 AM TO NOON EST MONDAY FOR WVZ046.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/RPY/SL/30
NEAR TERM...TRM
SHORT TERM...30
LONG TERM...SL
AVIATION...TRM
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
125 PM EST SUN DEC 21 2014
.SYNOPSIS...
WEAK HIGH PRESSURE EXITS THIS EVENING. SYSTEM CLIPS THE MOUNTAINS
MONDAY. STRONG LOW PRESSURE SYSTEM LIFTS NORTHEAST ACROSS THE OHIO
VALLEY THROUGH CHRISTMAS EVE.
&&
.NEAR TERM /THROUGH MONDAY/...
HIGH PRESSURE AND LIGHT E FLOW HAD MANAGED TO ERADICATE THE STRATUS
ALONG AND E OF THE OHIO RIVER TODAY. THIS HAS ALLOWED FOR DAYTIME
HEATING BUT WILL ALSO ALLOW FOR RADIATIVE COOLING THIS EVENING.
A WARM WAVE RIDES UP THE SE COAST LATE TONIGHT AND MON. THE
QUESTION IS TO WHAT DEGREE THIS FLAT WAVE CAN THROUGH PRECIPITATION
BACK INTO THE FCST AREA...AND WHEN WILL SUCH PRECIPITATION REACH THE
GROUND GIVEN THE DRY MID LEVEL AIR TO START OUT WITH.
MOST OF THE GUIDANCE SUGGESTS TEMPERATURES NEAR OR JUST BELOW
FREEZING IN THE NRN WV MOUNTAINS...MAINLY ON THE HIGHER PEAKS AND
DOWN THE ERN SLOPES INTO THE GREENBRIER VALLEY. MODELS DEPICT A
WARM LAYER ALOFT WITH TEMPERATURES 1-2C IN THE H925-H85 LAYER. THIS
SUGGESTS MELTING OF SNOW WHICH MEANS THERE COULD BE SLEET AND SNOW
MIXED IN WITH ANY FREEZING RAIN. TEMPERATURES IN CLOUD SUPPORTIVE
OF ICE CRYSTALS ARE LOST EARLY ON AS THE MOIST LAYER BECOMES MORE
SHALLOW. THIS WOULD TEND THE PRECIPITATION BACK TOWARD FREEZING
RAIN OR FREEZING DRIZZLE.
THIS LEAVES THE TIMING OF THE ARRIVAL OF PRECIPITATION CRUCIAL AS
TEMPERATURES SLOWLY CLIMB ABOVE FREEZING IN THE GREENBRIER VALLEY.
CURRENT GRID DEPICTION IS FOR POPS CLIMBING ABOVE 50 YIELDING
MEASURABLE QPF AS TEMPERATURES CLIMB. THIS LIMITS ICE ACCRETION TO
AT MOST A HUNDREDTH AND NOT VERY WIDESPREAD. THE SREF DOES
INTERSECT HIGH POPS WITH POCKETS OF HIGH PROBABILITIES FOR SFC
TEMPERATURES AT OR BELOW FREEZING MON MIDDAY INTO THE AFTERNOON.
COORD WITH WPC/WWD-PBZ-LWX-RNK ON ISSUANCE ADV FOR FREEZING RAIN
POCAHONTAS COUNTY 11-17Z.
THE REMAINDER OF THE FCST AREA SEES A RETURN OF CLOUD COVER
TONIGHT...SETTING THE STAGE FOR ANOTHER GREY DECEMBER DAY...ALTHOUGH
THE CLOUDS DO DECREASE BEHIND THE SYSTEM MON AFTERNOON.
USED NEAR TERM...IN PARTICULARLY THE WRFNMM...RUC AND THE HRRR FOR
TEMPERATURES TONIGHT AND NAM-BASED VALUES FOR THOSE ON MON...WHICH
SHOULD FEATURE A MILDER AFTERNOON.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
PESKY MOISTURE FROM WEAK SURFACE LOW ALONG THE E COAST AS WELL AS
WAA WILL COMBINE FOR LIGHT PRECIP MOVING UP THE MOUNTAINS MONDAY
MORNING. THERMAL PROFILES CONTINUE TO INDICATE A BRIEF ONSET OF
FZRA WITH PSBL SLEET...BEFORE CHANGING OVER TO LIQUID BY MIDDAY
AND PULLING OUT IN THE AFTERNOON. TEMPS SHOULD RECOVER BEHIND THIS
SYSTEM FOR THE AFTERNOON WITH AID OF DEVELOPING SE DOWN SLOPE FLOW.
SOME PEAKS OF SUN IS PSBL S OF I64 LATE IN THE DAY. AS THE SE FLOW
INCREASES MONDAY NIGHT AND WAA ALOFT CONTINUES...THINK THE RIDGES
WILL SEE RISING TEMPS OVERNIGHT AMID INCREASING CLOUDS OVER THE AREA.
THERE HAS BEEN A NOTICEABLE TREND IN THE MODELS REGARDING THE
MIDWEEK SYSTEM. MOST DELAY PHASING AND RAPID PRESSURE DROPS UNTIL
INTO CANADA. WHAT THIS DOES IS TO SLOW THE FRONT/NOW ABOUT 6 HRS/ AND
LESSEN THE MAGNITUDE OF SENSIBLE WX EFFECTS FROM THIS
SYSTEM...INCLUDING POST FRONTAL CAA...SURFACE TEMPS...AND EXTENT
AND DURATION OF SHSN BEHIND THE FRONT. HAVE MODIFIED THE GRIDS TO
INCORPORATE THIS TREND IN THE MODEL SUITE AND DELAYED CHANGEOVER
TO SHSN.
WITH THE SLOWER TIMING OF THE FRONT...LOOKS LIKE CHRISTMAS EVE
MAY BE JUST AS WARM AS TUESDAY WITH LOW TO MID 60S POSSIBLE BOTH
DAYS. STILL THINKING TUESDAY THE DAYLIGHT HRS ON TUESDAY IS DRY E
OF THE OH RIVER WITH SHRA MOVING INTO SE OH AND NE KY IN THE
AFTERNOON WHICH THEN OVERSPREADS REMAINDER OF AREA TUESDAY NIGHT
AND WEDNESDAY. IT WILL BE A MILD TUESDAY NIGHT DESPITE THE SHRA AS
LOW LEVEL SE FLOW REACHES ITS MAXIMUM. WHAT STILL LOOKS LIKELY ARE
THE STRONG GUSTY WINDS CHRISTMAS EVE NIGHT AND CHRISTMAS DAY
ITSELF...WITH 30 KTS PSBL ESPECIALLY ACROSS N ZONES AND IN THE
MOUNTAINS WHERE EVEN HIGHER GUSTS ARE EXPECTED.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ACTIVE WEATHER PATTERN CONTINUES IN THE LONG TERM PERIOD...WITH A
DEEPENING UPPER TROUGH ACROSS THE CENTRAL PLAINS AT THE BEGINNING OF
PERIOD...WITH A SURFACE LOW MOVING NORTHEAST OUT OF THE GULF STATES
TOWARDS THE REGION. STRONG SOUTHERLY WINDS WILL DEVELOP OUT AHEAD OF
THE SYSTEM...WITH GOOD MOISTURE TRANSPORT INTO THE AREA AS A RESULT.
THIS IS A STRONG SYSTEM...WITH STRONG PRESSURE FALLS/BOMBOGENESIS AS
THE LOW MOVES TOWARDS THE REGION. COLD FRONT STILL PROGGED TO MOVE
THROUGH THE AREA WEDNESDAY...WITH FALLING TEMPERATURES...STRONG
GUSTY WINDS ALONG AND BEHIND THE FRONT DUE TO TIGHT PRESSURE
GRADIENT...AND POTENTIAL FOR STRONG WINDS ALOFT TO MIX DOWN...AND
EVEN A SLIGHT CHANCE FOR THUNDER...MAINLY ACROSS THE WEST...AS THE
FRONT MOVES INTO THE REGION. STARTING TO LOOK MORE AND MORE LIKE
WINTER PRECIPITATION WILL NOT BE A HUGE HAZARD WITH THIS
SYSTEM...DUE TO THE OVERALL SPEED...AND THE FACT THAT BY THE TIME
ENOUGH COLD AIR IS IN PLACE...BULK OF MOISTURE SHOULD HAVE EXITED.
IN ADDITION...STILL QUITE A BIT OF UNCERTAINTY AS TO HOW MUCH WILL
ACTUALLY BE ABLE TO STICK TO THE GROUND IF GROUND TEMPERATURES ARE
TOO WARM AS TEMPERATURES WILL RISE INTO THE 50S OUT AHEAD OF THE
SYSTEM. HOWEVER...WILL STILL SEE A CHANGE OVER TO SNOW WEDNESDAY
NIGHT INTO THURSDAY...ALONG WITH FALLING TEMPERATURES. WILL CONTINUE
TO MAINTAIN HWO.
ON THURSDAY...UPPER LOW LIFTS NORTH ACROSS CANADA...BECOMING NEARLY
STACKED WITH SURFACE LOW. STILL A CHANCE FOR SOME LIGHT SNOW SHOWER
ACTIVITY ON THURSDAY...BUT WILL GRADUALLY SEE A DRYING TREND FROM
SOUTH TO NORTH AS THE SYSTEM PULLS AWAY.
ANOTHER FRONT APPROACHES LATE IN THE EXTENDED.
&&
.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
LIGHT E FLOW ON S SIDE OF HIGH PRESSURE HAD FINALLY ERADICATED THE
MVFR TO HIGH IFR STRATOCU...WITH ALL SITES VFR TO START THE FCST.
THIS WILL HOLD THROUGH SUNSET.
A WEAK WAVE OF LOW PRESSURE MOVES UP ALONG THE SE COAST OVERNIGHT
TONIGHT AND MON. THIS WILL SPILL CLOUDS BACK INTO THE AREA
OVERNIGHT...WITH RAIN LIKELY IN THE MOUNTAINS...MAINLY ON THE
EASTERN SLOPES...WHERE SNOW...SLEET AND FREEZING RAIN ARE LIKELY TO
BE MIXED IN THROUGH THE MORNING HOURS.
MVFR TO HIGH IFR STRATOCU SHOULD RETURN TO BKW TONIGHT...WITH A MORE
WIDESPREAD MVFR DECK DEVELOPING BY MON MORNING. CLOUD HEIGHTS
SHOULD INCREASE MON AFTERNOON AS CLOUD AMOUNT LOWERS.
LIGHT AND VARIABLE TO E SFC FLOW WILL BECOME LIGHT SE TONIGHT AND
REMAIN SO ON MON. SE WINDS WILL BECOME A BIT GUSTY ON THE RIDGES
INCLUDING BKW OVERNIGHT INTO MON. FLOW ALOFT WILL REMAIN LIGHT S TO
SW.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING AND LOCATION OF A MVFR STRATUS DECK
COULD VARY CONSIDERABLY OVERNIGHT INTO MON.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00
CRW CONSISTENCY M M M M H H H H H H H H
HTS CONSISTENCY H M M M H H H H H H H H
BKW CONSISTENCY H H H H H M M M M M L L
EKN CONSISTENCY M M H H H H H H H H H H
PKB CONSISTENCY M M M M M M M H H H H H
CKB CONSISTENCY M M M M M M H H H H H H
AFTER 18Z MONDAY...
IFR POSSIBLE IN MOUNTAINS INTO MON AFTERNOON IN A WINTRY MIX. IFR
POSSIBLE IN RAIN TUE NT INTO WED...CHANGING TO SNOW SHOWERS WED
NT...AS AN INTENSE LOW PRESSURE CENTER PASSES.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/RPY/SL/30
NEAR TERM...TRM
SHORT TERM...30
LONG TERM...SL
AVIATION...TRM
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
641 PM CST MON DEC 22 2014
.UPDATE...
INCREASED CLOUD COVER TONIGHT AND DELAYED RAIN CHANCES A FEW
HOURS IN WESTERN NORTH TEXAS.
&&
.DISCUSSION...
LIGHT RAIN MAY IMPACT LOCATIONS SOUTH OF THE RED RIVER
TONIGHT...MAINLY AFTER MIDNIGHT.
BASED ON LATEST SATELLITE AND HRRR MODEL OUTPUT...INCREASED
CLOUD COVER TONIGHT ACROSS THE AREA...ESPECIALLY SOUTH OF I-40.
LATEST RADARS INDICATED LIGHT PRECIPITATION OVER THE TEXAS HIGH
PLAINS TO OUR WEST...SOME OF WHICH WAS NOT REACHING THE GROUND
DUE TO DRY LOW LEVELS. THINK SOME OF THIS PRECIPITATION WILL REACH
THE GROUND ONCE IT ENTERS WESTERN NORTH TEXAS IN THE NEXT FEW
HOURS...BUT FOR THE MOST PART...MEASURABLE PRECIPITATION...0.01
INCH OF RAINFALL OR GREATER...IS EXPECTED TO OCCUR AFTER MIDNIGHT.
MODEL PROFILES SUPPORT ALL LIQUID AT THE GROUND WITH THIS
PRECIPITATION WITH WET BULB ZERO HEIGHTS ABOVE 1500 FT AGL.
PRODUCTS HAVE BEEN UPDATED.
MBS
&&
.PREV DISCUSSION... /ISSUED 539 PM CST MON DEC 22 2014/
AVIATION...
MOSTLY VFR CONDITIONS IN THE 00Z TAFS... FINALLY. AN EXCEPTION MAY
BE OVER FAR SOUTHWEST OKLAHOMA AND WESTERN NORTH TEXAS TUESDAY
MORNING AS SOME MVFR VSBY/CIGS WILL BE POSSIBLE... MOST LIKELY AT
KSPS. THE HIGHEST CHANCES OF PRECIPITATION WILL BE SOUTH OF OUR
TAF SITES.
PREV DISCUSSION... /ISSUED 303 PM CST MON DEC 22 2014/
DISCUSSION...
A FEW WEAK ECHOES ARE SHOWING UP ON AREA RADARS. MEASURABLE
PRECIPITATION IS NOT EXPECTED THROUGH EARLY EVENING...ALTHOUGH A
FEW SMALL PATCHES OF DRIZZLE OR SPRINKLES CANNOT BE RULED OUT.
AN AREA OF MOISTURE AND ISENTROPIC LIFT WILL ACCOMPANY A MID-LEVEL
WAVE ACROSS OUR TEXAS AND FAR SOUTHERN OKLAHOMA COUNTIES
OVERNIGHT AND EARLY TUESDAY. THERE WILL BE A TIGHT GRADIENT OF
RAIN CHANCES ALONG THE NORTHERN EDGE. TEMPERATURES WILL BE WARM
ENOUGH FOR ALL RAIN...EXCEPT POSSIBLY ALONG THE NORTHERN
FRINGE...WHERE A MIX OF RAIN/SNOW MAY OCCUR EARLY TOMORROW
MORNING.
FOR TUESDAY NIGHT INTO EARLY WEDNESDAY...ANOTHER GLOB OF MOISTURE
IS FORECAST TO FOLLOW BEHIND THE DEPARTING STORM SYSTEM. THIS
WILL BRING A CHANCE OF LIGHT SNOW TO NORTHERN OKLAHOMA. MINIMAL
LIFT IS EXPECTED IN THIS PART OF THE STORM SYSTEM...SO ONLY VERY
LIGHT ACCUMULATION IS EXPECTED IN THE NORTHWEST. A MIX OF LIGHT
RAIN AND SNOW MAY EXTEND AS FAR SOUTH AS CENTRAL OKLAHOMA.
STRONG NORTHWEST WINDS ARE EXPECTED TOMORROW...ENHANCED BY COLD
AIR ADVECTION. A WIND ADVISORY MAY BE NEEDED TOMORROW...DEPENDING
ON THE WIND GUIDANCE TRENDS.
CHRISTMAS DAY WILL BE WINDY...WARM...AND DRY. IF CURRENT MODEL
GUIDANCE IS ANYWHERE CLOSE TO CORRECT...A WIND ADVISORY WILL BE
NECESSARY...AND A HIGH WIND WATCH/WARNING MAY NEED TO BE
CONSIDERED. MOST MODELS SHOW 30-50 KT WINDS BETWEEN 850 MB AND THE
LOWEST LAYER ABOVE THE SURFACE.
A COLD FRONT WILL ARRIVE FRIDAY...BRINGING A NOTICEABLE DROP IN
TEMPERATURES. THE WEEKEND IS CURRENTLY BEYOND THE RANGE OF
COHERENT MODEL FORECASTS. THEY DIVERGE QUITE SERIOUSLY AROUND
SATURDAY...SO THE WEEKEND FORECAST IS CURRENTLY A MIX OF GUIDANCE
WITH LOW CONFIDENCE LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 37 48 33 43 / 10 10 20 10
HOBART OK 36 48 31 46 / 10 10 10 0
WICHITA FALLS TX 40 51 34 48 / 20 20 10 0
GAGE OK 32 42 28 45 / 10 20 20 0
PONCA CITY OK 34 46 33 41 / 10 10 20 10
DURANT OK 42 51 36 45 / 20 50 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
17/26/26
AREA FORECAST DISCUSSION
NWS TULSA OK
1127 PM CST SAT DEC 20 2014
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
WIDESPREAD LOW CLOUDS AND PATCHY DRIZZLE WILL RESULT IN FURTHER
DETERIORATING CONDITIONS OVERNIGHT WITH ALL AREAS TRANSITIONING TO
IFR/LIFR. GENERALLY OVERCAST CONDITIONS WILL PREVAIL THROUGH THE
FORECAST PERIOD THOUGH VISIBILITY SHOULD IMPROVE AFTER 18Z WITH AT
LEAST SOME IMPROVEMENT IN CEILINGS AS WELL...MOST AREAS MVVFR
AFTER 18Z.
&&
.PREV DISCUSSION... /ISSUED 906 PM CST SAT DEC 20 2014/
UPDATE...
PATCHY DRIZZLE WAS ADDED TO THE EVENING FORECAST...SEE DISCUSSION BELOW.
DISCUSSION...
A FEW HOLES IN THE STRATUS DECK DEVELOPED DURING THE DAY...BUT THE
CLOUDS HAVE FILLED BACK IN AT ALMOST ALL LOCATIONS /COPAN WILL
CLOUD UP SOON/ AS OF 03Z. CLOUDS WILL HANG ON THRU THE
NIGHT...CONTINUING A STRING OF CLOUDY DAYS AND NIGHTS THAT
STRETCHES BACK TO THE 17TH. AS SUCH...LOWS WILL NOT BE MUCH
DIFFERENT FROM TODAY`S HIGHS AND THE FORECAST IS WITHIN REASON OF
THE LATEST HRRR GUIDANCE. IN ADDITION...WEAK WARM ADVECTION IN THE
LOW LEVELS IS PROVIDING JUST ENOUGH LIFT FOR PATCHY
DRIZZLE...WHICH SHOWS UP ON RADAR AND IN SOME OF THE METAR OBS.
THEREFORE...HAVE ADDED PATCHY DRIZZLE THRU THE NIGHT TO THE GRIDS. NO
OTHER CHANGES ARE PLANNED TO THE FORECAST THIS EVENING.
LACY
PREV DISCUSSION... /ISSUED 525 PM CST SAT DEC 20 2014/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
WIDESPREAD LOW CLOUDS WILL PERSIST THROUGH THE ENTIRE FORECAST
PERIOD. MVFR CONDITIONS EARLY THIS EVENING WILL TRANSITION TO IFR
AS CEILINGS LOWER AND VISIBILITY EVENTUALLY BECOMES REDUCED
OVERNIGHT...SOME AREAS LIKELY TO SEE A PERIOD OF LIFR CEILINGS AS
WELL 12-18Z. MODEST IMPROVEMENT AFTER 18Z SUNDAY.
PREV DISCUSSION... /ISSUED 348 PM CST SAT DEC 20 2014/
DISCUSSION...
ANOTHER CLOUDY DAY FOR TSA CWA. CLOUDS LIKELY ANCHORED
FOR ANOTHER COUPLE OF DAYS BEFORE SUN ARRIVES ON 24TH.
MAX / MIN TEMP ADJUSTMENTS MADE FOR MAINLY CLOUDY SKY.
H500 WAVE FROM WESTERN CANADA WILL DROP INTO NORTHERN
& CENTRAL PLAINS OVER THE NEXT COUPLE OF DAYS AS WEST
COAST H500 RIDGE AMPLIFIES. ELONGATED TROUGH - CENTRAL
CANADA TO TEXAS BY TUESDAY. THIS EVOLUTION WILL BRING
CHANCE PRECIP MONDAY THROUGH TUESDAY. ECMWF WRF GFS &
DIFFER SOME WITH THIS SYSTEM. OF PARTICULAR CONCERN IS
HOW FAST COLD AIR WILL ARRIVE IN EASTERN OK NORTHWEST
AR TUESDAY. IF THE COLD AIR ARRIVES EARLY THE TAIL END
OF PRECIPITATION LATE TUESDAY/TUESDAY NIGHT WOULD BE A
WINTRY MIX. GIVEN THAT THE BEST CHANCE FOR PRECIP WILL
BE TUESDAY WITH HIGH TEMPS IN LOW/MID 40S DID NOT PUT
POSSIBLE WINTRY MIX IN UNTIL TUESDAY NIGHT. AND...THEN
JUST SLIGHT CHANCE EXTREME EASTERN OK AND NORTHWEST AR.
RIDGE MOVES ACROSS THE REGION CHRISTMAS DAY WHILE NEXT
UPPER WAVE DIVES FROM PACIFIC NORTHWEST TO THE ROCKIES.
CHRISTMAS DAY PROMISES TO OFFER LOTS OF SUN WITH HIGH
TEMPERATURES ABOVE NORMAL IN THE 50 TO 60 DEGREE RANGE.
COLD FRONT WILL SWEEP THROUGH CHRISTMAS NIGHT / FRIDAY
LEAVING BELOW AVERAGE TEMPS NEXT WEEKEND. GW
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...99
LONG TERM....99
AVIATION...14
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
303 PM EST SUN DEC 21 2014
.SYNOPSIS...
A MOIST AIR MASS WILL REMAIN ACROSS THE REGION BEFORE A COLD FRONT
CROSSES EAST ON WEDNESDAY. DRY CANADIAN HIGH PRESSURE WILL BUILD IN
THURSDAY AND PERSIST INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH MONDAY/...
AS OF 230 PM...THE STRATUS DECK CONTINUES TO ERODE SLOWLY ACRS THE
MTNS AND LOWER PIEDMONT THIS AFTN...RESULTING IN SLIGHTLY WARMER
TEMPS UNDER MORE SUNSHINE. MOST THE AREA IS STILL OVERCAST OR MOSTLY
CLOUDY...WITH TEMPS IN THE 40S TO LWR 50S.
GUIDANCE IN GOOD AGREEMENT ON A DIGGING TROF TO THE WEST AND A
BUILDING RIDGE ALONG THE EAST COAST TONIGHT THRU MONDAY. SHORTWAVE
ENERGY WILL RIDE FROM SW TO NE THRU THE FLOW ATOP THE SOUTHEAST
STATES...INDUCING A WEAK WAVE ALONG A COASTAL FRONT OFF THE SC COAST
ON MONDAY. INCREASING SOUTHERLY UPGLIDE AND 850 MB WAA FLOW ATOP THE
CWFA. POPS QUICKLY RAMP UP TO CATEGORICAL ACRS THE SOUTHERN HALF OF
THE CWFA...AND LIKELY TO THE NORTH BY LATE EVENING. THE COVERAGE
WILL BE AIDED BY SOME DEEP LAYER Q-VECTOR CONVERGENCE WITHIN THE
SWLY MID-UPR FLOW. HOWEVER...THE MOISTURE DEPTH WILL BE FAIRLY
SHALLOW...AND FORCING OVERALL WEAK. SO QPF AMOUNTS SHUD BE GENERALLY
A FEW HUNDREDTHS TO A TENTH OF AN INCH. ALTHO...A TENTH TO QUARTER
INCH POSSIBLE AROUND THE CHARLOTTE METRO AREA. ONE THING TO MENTION
IS THAT THERMAL PROFILES ARE MARGINAL FOR SOME FREEZING RAIN AND
SLEET ACRS THE NRN MTNS...MAINLY AVERY COUNTY. THE 12Z NAM AND
LATEST RAP KEEP THINGS JUST ABOVE FREEZING. I WOULDN/T BE SURPRISED
IF A FEW SPOTS NEAR THE EASTERLY UPSLOPE AREAS IN AVERY/CALDWELL MAY
HAVE BRIEF FZRA/DZ TOWARD DAYBREAK MONDAY. HOWEVER...CONFIDENCE IS
JUST NOT HIGH ENUF TO ISSUE A FREEZING RAIN ADVISORY AT THIS TIME.
IF THE 18Z NAM COMES IN COLDER...OR IF TRENDS SEEM TO WARRANT
IT...THE EVENING SHIFT MAY WANT TO ISSUE ONE OR AN SPS.
OTHERWISE...IT SHUD BE JUST A COLD RAIN WITH TEMPS IN THE 30S TO LWR
40S.
ON MONDAY...THE MID LVLS DRY OUT...AND THE BETTER FORCING EXITS TO
THE EAST. HOWEVER...A WEDGE IS EXPECTED TO REMAIN...WITH LLVL
UPGLIDE CONTINUING WITHIN SWLY FLOW. THIS LOOKS LIKE A GOOD SETUP
FOR AREAS OF -DZ PERSISTING...ALSO KEEPING TEMPS DOWN. GOING CLOSE
TO THE RAW MODEL TEMPS FOR HIGHS...AND KEEPING A CHC OF -RA AND DZ
THRU THE DAY. HIGHS WILL LIKELY STRUGGLE TO GET INTO THE 40S ACRS
THE I-40 CORRIDOR...AND ONLY THE MID TO UPR 40S ELSEWHERE.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 230 PM EST SUNDAY...MON NIGHT THROUGH TUESDAY NIGHT...LATEST
12Z MODELS CONTINUE TO INDICATE THAT SURFACE COLD AIR DAMMING WEDGE
WILL CONTINUE ACROSS THE AREA AS 1030MB HIGH WILL REMAIN ANCHORED
OVER THE NE. MEANWHILE...STRONG SSWLY FLOW ALOFT DEVELOPS ACROSS THE
SE BY TUE AS A DEEP UPPER TROUGH MOVES EAST ACROSS THE CENTRAL CONUS
WHILE AN UPPER RIDGE AMPLIFIES OVER THE WESTERN ATLANTIC. THIS WILL
LEAD TO INCREASING 290K ISENTROPIC LIFT/ATLANTIC MOISTURE ADVECTION
OVER OUR CWA THRU TUESDAY. HENCE...HAVE CARRIED CHANCE POPS FOR
LIGHT RAIN WITH DRIZZLE MON NIGHT INTO TUE MORNING...RAMPING UP INTO
THE CATEGORICAL POPS WITH STEADY RAIN TOWARDS TUE NIGHT. WITH
ONGOING PRECIP WITHIN THE CAD...AFTERNOON TEMPS ON TUE WILL RUN 7-10
DEGREES BELOW NORMAL OVER THE PIEDMONT WITH 3-5 DEGREES BELOW OVER
THE WESTERN NC MTNS.
WEDNESDAY...THE UPPER TROUGH OVER THE MISSISSIPPI VALLEY WILL
ADVANCE EASTWARD...BECOMING POSITIVELY TILED AS IT PUSHES THROUGH
THE EASTERN CONUS. THIS WILL LIFT A SURFACE LOW INTO THE OHIO VALLEY
BY 18Z...PUSHING ITS ASSOCIATED COLD FRONT THROUGH THE FORECAST AREA
BETWEEN 18Z WED AND 00Z THU. ALTHOUGH THERE WILL BE STRONG LLVL WIND
SHEAR ALONG AND AHEAD OF THE FRONT...THE BEST UPPER FORCING WILL NOT
REACH THE AREA UNTIL 00Z THU AND AREAS SBCAPE REGIME WILL REMAIN
SOUTH OF THE AREA. THEREFORE...HIGH SHEAR LOW CAPE SEVERE EVENT
APPEARS LOW AT THIS TIME. AS FOR QPF...MODELS STILL DEPICT
WIDESPREAD CONVECTIVE ACTIVITY ALONG THE GULF COAST/SE COAST...WHICH
COULD BLOCK DEEP MOISTURE TRANSPORT INTO OUR AREA. WITH THE
UNCERTAINTY...HAVE GONE WITH THE MODEL CONSENSUS QPF...YIELDING 1-2
INCHES ACROSS THE REGION WITH UP TO 3" OVER THE BLUE RIDGE
ESCARPMENT. CATEGORICAL POPS WERE HIGHLIGHTED THRU 18Z WED...
QUICKLY RAMPING DOWN TO THE CHANCE RANGE FROM WEST TO EAST THRU 00Z
THU AS THE FRONT PUSHES TO THE EAST. WITH INCREASING WAA
FLOW...AFTERNOON TEMPS WILL WARM INTO THE U50S/60S EAST OF THE MTNS
AND 50S OVER THE MTNS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 200 PM SUNDAY...THE LATE WEEK WILL SEE THE SHARP UPPER TROUGH
PUSH OFF THE EAST COAST...LEAVING QUASI-ZONAL FLOW OVER THE ERN THIRD
OF THE CONUS. DRY HIGH PRESSURE WILL CROSS THE SOUTHEAST BEFORE
HEIGHTS FALL OVER THE MISSISSIPPI VALLEY AS NEXT LOW ROLLS OFF THE
ROCKIES AND ACRS THE GREAT LAKES. DIFFERENCES BETWEEN THE GFS AND EC
ARE MINOR IN TERMS OF SENSIBLE WX CHRISTMAS DAY AND FRIDAY...BOTH
INDICATING NW FLOW PRECIP TAPERING OFF CHRISTMAS MRNG FOLLOWED BY DRY
WX MOST OF FRIDAY. IN COLD ADVECTIVE PATTERN HIGHER ELEVATIONS WILL
LIKELY SEE BREEZY/GUSTY CONDITIONS ON CHRISTMAS. THE COLD FRONT
ASSOCIATED WITH THE GRT LAKES LOW WILL ARRIVE BY FRIDAY NIGHT ALBEIT
WITHOUT MUCH OOMPH...THE GFS PRETTY MUCH WASHING THE FRONT OUT OVER
THE CAROLINAS. THE EC HOWEVER DIVERGES AT THIS POINT...STALLING THE
FRONT ALONG THE COAST AND EVENTUALLY DEVELOPING A COASTAL LOW NEAR
THE OUTER BANKS SUNDAY IN RESPONSE TO A SRN STREAM SHORTWAVE TRAILING
THE FRONT. BOTH THE 21/00Z AND 21/12Z RUNS FEATURE THIS EVOLUTION. SO
WHILE THE GFS WOULD SUGGEST NEXT WEEKEND WILL BE QUIET AND DRY...EC
INDICATES SOME PTYPE ISSUES MAY EXIST SUNDAY WITH WINTRY PARTIAL
THICKNESSES AND THERMAL PROFILES. TEMPS WILL BE AT OR A LITTLE ABOVE
CLIMO FROM THU-SAT...AND BELOW NORMAL SUNDAY IF THE CLOUDS/PRECIP
MATERIALIZE.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
AT KCLT...THE MVFR CIGS HAVE FINALLY SCATTERED OUT...BUT SOME
CONTINUE TO LINGER TO THE NORTH AND WEST OF THE TERMINAL THIS AFTN.
LOW VFR CLOUDS WILL CONTINUE THRU THE AFTN. THEN MVFR CIG RETURN BY
EARLY EVENING. LIGHT RAIN IS EXPECTED TO DEVELOP TONIGHT AS A
SURFACE LOW MOVES UP THE COAST. IFR CIGS AND MVFR VSBY EXPECTED WITH
THE PRECIP. RAIN WILL TAPER OFF BY LATE MONDAY MORNING...BUT LOW
CLOUDS AND DRIZZLE WILL LINGER THRU AT LEAST MIDDAY. WINDS ARE
EXPECTED TO FAVOR THE NE THRU THE PERIOD...AS WEAK COLD AIR DAMMING
REGIME DOMINATES.
ELSEWHERE...CIGS HAVE BEEN VARIABLE ACRS THE REGION TODAY...AND IT
WILL PROBABLY CONTINUE THAT WAY THRU THE REST OF THE AFTN...PER
SATELLITE TRENDS. GENERALLY MVFR TO OCCASIONAL VFR CONDITIONS
EXPECTED. THEN CONDITIONS WILL DETERIORATE THIS EVENING...AS
MOISTURE AND PRECIP MOVES IN FROM THE SOUTHWEST...AS A SFC LOW MOVES
UP THE COAST. CIGS ARE EXPECTED TO GO TO IFR...WITH SOME VSBY
RESTRICTIONS POSSIBLE UNDER -RA AND DZ. THE LIGHT RAIN WILL TAPER OFF
MONDAY MORNING...BUT AREAS OF -DZ WILL LIKELY LINGER THRU AT LEAST
MIDDAY...ESP ACRS THE UPSTATE. WINDS WILL CONTINUE IN THE USUAL COLD
AIR DAMMING PATTERN...WITH LIGHT NE WINDS EAST OF THE MTNS AND SE AT
KAVL.
OUTLOOK...LINGERING LOW LEVEL MOISTURE IS LIKELY TO KEEP LOW STRATUS
AROUND THRU MONDAY. A COLD FRONT WILL APPROACH ON TUESDAY FROM THE
WEST AND MOVE THROUGH ON WED. WIDESPREAD SHOWERS WITH RESTRICTIONS
SHOULD ARRIVE TUESDAY AFTERNOON AND WILL CONTINUE UNTIL THE FRONT
CLEARS THE AREA LATE WEDNESDAY.
CONFIDENCE TABLE...
20-02Z 02-08Z 08-14Z 14-18Z
KCLT HIGH 100% MED 72% LOW 54% MED 78%
KGSP HIGH 94% LOW 54% MED 73% HIGH 81%
KAVL HIGH 80% HIGH 87% MED 76% HIGH 87%
KHKY HIGH 98% HIGH 82% MED 72% HIGH 85%
KGMU HIGH 96% LOW 58% MED 73% HIGH 81%
KAND HIGH 92% LOW 46% MED 67% HIGH 87%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...SBK
NEAR TERM...ARK
SHORT TERM...JOH
LONG TERM...WIMBERLEY
AVIATION...ARK
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
323 PM CST SUN DEC 21 2014
.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 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1146 AM CST SUN DEC 21 2014
LIFR TO IFR CIGS AND VIS CONTINUE OVER A GOOD PORTION OF THE AREA.
CLEARING STARTING TO MAKE PROGRESS EAST...CURRENTLY NEAR THE
JAMES RIVER. THIS CLEARING COULD MAKE IT AS FAR EAST AS KHON OR
KFSD...SO WILL CONTINUE TO MONITOR TRENDS. FOR NOW WILL KEEP THE
TAFS PESSIMISTIC AS STILL THINK THAT IS THE MORE LIKELY SOLUTION.
WILL SEE RAIN DEVELOP LATER TONIGHT...POSSIBLY MIXED WITH SOME
SLEET. CIGS COULD BUMP UP INTO IFR OR LOW END MVFR AFTER THE RAIN
STARTS...AND VIS SHOULD NOT BE AS BAD AS THIS MORNING. RAIN WILL
SLOWLY TRANSITION TO SNOW...BUT THINK AREAS EAST OF THE JAMES
RIVER WILL PROBABLY BE PREDOMINATELY RAIN THROUGH 18Z.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHENARD
LONG TERM...08
AVIATION...CHENARD
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1135 PM CST SAT DEC 20 2014
.UPDATE...
SEE UPDATED AVIATION DISCUSSION BELOW.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
LOW CLOUDS AND FOG WILL ONCE AGAIN BE THE RULE OVERNIGHT AS A VERY
MOIST LOW LEVEL AIR MASS REMAINS IN PLACE. BEEN CLOSELY FOLLOWING
THE HRRR LOW-LEVEL CLOUD COVER PRODUCT WHICH HAS BEEN DOING AN
AMAZING JOB WITH HANDLING STRATUS DECKS THE PAST SEVERAL EVENTS.
IT BASICALLY SHOWS THE STRATUS CLOUDS REMAINING IN PLACE ALL NIGHT
WITH A SLIGHT WESTWARD PUSH ONCE AGAIN ON ITS WESTERN EDGE. WILL
GO WITH PERSISTENCE FORECAST CONCERNING THE FOG AS IT HAS BEEN
OCCURRING THE PAST FEW NIGHTS UNDERNEATH THE STRATUS...SO NO
REASON WHY IT WONT HAPPEN AGAIN...AND IN FACT WIDESPREAD LIGHT FOG
IS ALREADY IN PLACE...WITH LOCALLY THICKER FOG. SEEMS THE MOIST
LAYER IS TOO SHALLOW FOR ANY MEANINGFUL FREEZING DRIZZLE TO OCCUR
OVERNIGHT BUT SOMETHING TO KEEP AN EYE ON ANYWAY.
ON SUNDAY...EXPECTING LOW CLOUDS TO HANG IN TOUGH ACROSS THE EAST
ONCE AGAIN WITH NO REAL SIGNALS FROM ANYTHING TO CLEAR THEM OUT.
WILL ALSO BE WATCHING ARRIVAL OF THE LOW PRESSURE SYSTEM WHICH
WILL ENTER THE DAKOTAS BY SUNDAY EVENING...THEN MOVE INTO WESTERN
MINNESOTA AND IOWA REGION BY MONDAY NIGHT. MODELS STILL HAVING A
TOUGH TIME HANDLING THIS SYSTEM IN REGARDS TO STRENGTH MAINLY.
THEY REALLY DO NOT KNOW HOW TO HANDLE THE EVENTUAL CLOSING OFF AND
SUBSEQUENT MOVEMENT OF THE UPPER LOW...AND ITS ASSOCIATED MOISTURE
AVAILABILITY. THIS WILL BE KEY IN FIGURING OUT JUST HOW MUCH WRAP
AROUND PRECIPITATION WE RECEIVE. BASICALLY TOOK A BLENDED APPROACH
FOR RIGHT NOW WHICH STILL LEAVES THE AREA WITH A COUPLE INCHES OF
SNOW AND SOME MIXED PRECIP IN THE FORM OF FREEZING RAIN AND SLEET
TO START THINGS OFF SUNDAY EVENING. THERMAL PROFILES EVENTUALLY
GET COLD ENOUGH BY MONDAY TO CHANGE THINGS OVER TO SNOW. STILL
HAVE MANY DOUBTS AND LOW CONFIDENCE IN EXACTLY JUST HOW THIS
SYSTEM WILL EVOLVE AND HOW MUCH MOISTURE WILL REALLY BE ASSOCIATED
WITH IT. HAVE A FEELING MODELS MAY NOT LATCH ON TO A MORE
DEFINITIVE SOLUTION UNTIL SOMETIME SUNDAY.
.LONG TERM...TUESDAY THROUGH SATURDAY
LOW PRESSURE WILL BE EAST OF THE REGION WHEN THE PERIOD STARTS
WITH THE POTENTIAL FOR LINGERING SNOW SHOWERS...MAINLY ACROSS THE
EASTERN PART OF THE CWA THROUGH THE DAY TUESDAY. A DECENT PRESSURE
GRADIENT ACROSS THE AREA MAY RESULT IN BREEZY TO WINDY CONDITIONS
AS WELL. WEAK HIGH PRESSURE THEN MOVES IN WITH DRY CONDITIONS
EXPECTED WEDNESDAY. ANOTHER LOW PRESSURE SYSTEM LOOKS TO TRACK
ACROSS THE CENTRAL PLAINS ON THURSDAY...BUT THE MODELS ARE NOT IN
VERY GOOD AGREEMENT WITH STRENGTH OR TIMING. THE GFS AND ECMWF
AGREE SOMEWHAT ON THE TIMING WITH THE GEM BEING MUCH SLOWER.
HOWEVER...THE GFS BRINGS LITTLE IN THE WAY OF
PRECIPITATION...WHILE THE ECMWF PLASTERS MOST OF THE STATE, FOR
NOW...WILL STICK FAIRLY CLOSE TO THE SUPERBLEND KEEPING SCHC/CHC
POPS MAINLY ACROSS THE SOUTHERN CWA THURSDAY INTO THE DAY FRIDAY.
HIGH PRESSURE WILL MOVE BACK IN AFTER THAT WITH DRY CONDITIONS
FRIDAY NIGHT THROUGH THE DAY SATURDAY.
SLIGHTLY ABOVE NORMAL TEMPERATURES WILL BE THE RULE FOR THE FIRST
HALF OF THE PERIOD...WITH HIGHS MAINLY IN THE MID 20S TO LOWER 30S
TUESDAY...WEDNESDAY AND THURSDAY. COOLER AIR THEN MOVES IN BEHIND
THE STORM SYSTEM...WITH HIGHS IN THE TEENS AND 20S FRIDAY AND
SATURDAY.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
IFR CIGS WILL REMAIN IN PLACE ACROSS THE EASTERN HALF OF THE CWA
THROUGH THE TAF PERIOD. UNDER THE LOW CLOUDS...VSBYS WILL
GENERALLY BE MVFR IN FOG...BUT THERE WILL LIKELY BE PERIODS OF
IFR VSBYS INTO EARLY SUNDAY MORNING...AFFECTING KABR AND KATY.
VFR CONDITIONS WILL PREVAIL ACROSS THE WESTERN HALF OF THE CWA
BUT KPIR COULD SEE SOME IFR VSBY IN FOG TOWARD MORNING AGAIN.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...WISE
SHORT TERM...TMT
LONG TERM...PARKIN
AVIATION...WISE
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1103 PM CST SAT DEC 20 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 221 PM CST SAT DEC 20 2014
MUCH OF THE SAME EXPECTED TONIGHT INTO TOMORROW WITH THE LOW
CLOUDS HANGING TOUGH OVER A MAJORITY OF THE AREA. DO NOT REALLY
EXPECT THE CLEARING LINE TO MOVE MUCH THROUGH TOMORROW...WITH ONLY
GREGORY...BRULE AND PORTIONS OF CHARLES MIX COUNTIES SEEING ANY
CLEARING AND SUN. SIGNAL THAT THE DENSER FOG MAY ENCOMPASS MORE OF
THE AREA TONIGHT...MAKING IT TO AROUND THE INTERSTATE 29 CORRIDOR.
SO WILL HAVE TO KEEP AN EYE ON THIS...FOR NOW INCREASED MENTION OF
FOG IN THE GRIDS. GFS AND RAP SUGGEST LOW LEVEL MOISTURE DEPTH WILL
INCREASE TONIGHT AHEAD OF A WEAK UPPER WAVE THAT CROSSES THE REGION.
THIS HAPPENS MAINLY ACROSS PORTIONS OF NORTHWEST IOWA FROM SIOUX
CITY TO SPENCER. SO COULD POTENTIALLY SEE SOME PATCHY DRIZZLE OR
FREEZING DRIZZLE IN THAT AREA...BUT ANYTHING SHOULD BE LIGHT.
GIVEN THE CLOUD COVER...DIURNAL RANGE OF TEMPERATURES WILL BE SMALL.
WILL NOT FALL MUCH TONIGHT...WITH UPPER 20S TO LOW 30S EXPECTED.
THEN ON SUNDAY WE WILL ONLY WARM UP SEVERAL DEGREES...WITH 30S
ACROSS MOST OF THE REGION. WILL START TO BECOME A BIT BREEZY OUT OF
THE SOUTH BY LATER SUNDAY...WITH GUSTS AROUND 25 MPH EAST OF THE
JAMES RIVER.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 221 PM CST SAT DEC 20 2014
PRECIPITATION LIKELY TO DEVELOP ON SUNDAY...WITH THE BETTER CHANCES
IN THE EASTERN CWA. WHILE THE MAIN WARM FRONT IS TO THE NORTH OF THE
AREA...THE PV ANOMOLY AND COLD FRONT ALOFT SWING THROUGH SUNDAY
NIGHT AND SHOULD ALLOW WHAT WILL BE MAINLY RAIN. THE NORTHERN AND
WESTERN CWA COULD SEE SOME MIXED PRECIPITATION BUT THE CHANCES FOR
PRECIPITATION A LITTLE LOWER IN THESE LOCATIONS SO HOPEFULLY LITTLE
OR NO ACCUMULATION. TEMPERATURES REMAIN PRETTY MILD THROUGH THE
NIGHT AS WELL WITH LOW PRESSURE WRAPPING UP TO THE NORTH AND WEST OF
THE AREA SO MAINLY SOUTHERLY OR WESTERLY FLOW. LOWS GENERALLY FROM
THE LOWER TO MIDDLE 30S.
LOOKS LIKE EVERYONE SHOULD WARM TO AT LEAST THE MID 30S ON MONDAY
WITH LOWER 40S LIKELY IN PARTS OF NORTHWEST IOWA. THE DAYTIME
CHANCES FOR PRECIPITATION SHOULD NOT BE REAL HIGH AND WILL KEEP MOST
LOCATIONS IN THE CHANCE CATEGORY AS THE AREA WAITS FOR THE WRAP
AROUND TO SET UP LATE MONDAY AFTERNOON INTO MONDAY NIGHT. RIGHT NOW
LOOKING LIKE MAINLY A RAIN TO SNOW TRANSITION WITH LITTLE CHANCE FOR
SLEET AND FREEZING RAIN MONDAY AND MONDAY NIGHT.
THE CHANCE FOR SNOW WILL LINGER INTO TUESDAY BUT AMOUNTS WILL REMAIN
FAIRLY MINIMAL. WHEN ALL IS SAID AND DONE LOOKING AT ABOUT A HALF AN
INCH TO AN INCH OVER NORTHWEST IOWA TO 2 TO 3 INCHES FROM HURON TO
MARSHALL. A WAVE TRACKS THROUGH TO THE NORTH OF THE AREA ON TUESDAY
WHICH WILL BRING SOME DRYING ALOFT AND BRING AN END TO THE THREAT
FOR PRECIPITATION TUESDAY NIGHT INTO WEDNESDAY.
THE UPPER LEVEL PATTERN REMAINS FAIRLY ACTIVE THROUGH THE EXTENDED
PERIOD WITH ONE WAVE EXITING ON WEDNESDAY AND ANOTHER MOVING INTO
THE AREA FRIDAY INTO SATURDAY. STILL SOME DECENT DIFFERENCES FOR THE
INCOMING SYSTEM SO NOT OVERLY CONFIDENT ON WHAT TO EXPECT BUT RIGHT
NOW LOOKS COLD ENOUGH FOR ALL SNOW...JUST A MATTER OF WHETHER OR NOT
THIS IS A SYSTEM THAT MOVES THROUGH RATHER QUICKLY OR ONE THAT TAKES
ON JUST A TOUCH OF NEGATIVE TILT LIKE THE ECMWF SUGGESTS AND BRINGS
IN A BETTER CHANCE FOR HEAVIER AMOUNTS. UNFORTUNATELY NO WAY TO
REALLY FIGURE THIS OUT RIGHT NOW SO WILL CONTINUE TO CARRY A CHANCE
OF SNOW THURSDAY NIGHT INTO SATURDAY. FOR NOW WEDNESDAY AND THURSDAY
LOOK MAINLY DRY WITH SLIGHTLY BELOW NORMAL HIGH TEMPERATURES THROUGH
THE PERIOD. OVERNIGHT LOWS WILL LIKELY BE AT OR ABOVE NORMAL DURING
THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1103 PM CST SAT DEC 20 2014
POOR AVIATION CONDITIONS WILL CONTINUE THROUGH THE PERIOD...WITH
IFR TO LIFR CIGS AND VIS LIKELY. NOT REALLY EXPECTING MUCH CHANGE
FROM THE CURRENT CONDITIONS...SO MAINLY WENT WITH A PERSISTENCE
FORECAST. AREAS OF DENSE FOG AND VLIFR CIGS DEVELOPING THROUGH THE
CENTRAL PORTIONS OF THE FORECAST AREA...PARTICULARLY IN HIGHER
ELEVATIONS EAST OF THE JAMES RIVER VALLEY. STRONGER BOUNDARY LAYER
WINDS DEVELOP BY SUNDAY AFTERNOON...WHICH COULD HELP LIFT CEILINGS
INTO MVFR RANGE FOR A FEW HOURS TOWARD THE END OF THE TAF PERIOD BUT
CONFIDENCE IS LOW SO WILL STICK WITH IFR FOR NOW. COULD SEE SOME
LIGHT RAIN/DRIZZLE DEVELOP TOWARD THE END OF THE PERIOD...BUT TIMING
IS UNCERTAIN SO HAVE ONLY INTRODUCED AT KHON AT THIS TIME.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHENARD
LONG TERM...08
AVIATION...JH
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
1022 AM EST SUN DEC 21 2014
.DISCUSSION...
CLOUD COVER CONTINUES TO BE A CHALLENGE TODAY AS THE MODELS HAVE
NOT HANDLED THEM WELL AT ALL...AND HAVE BEEN TOO QUICK TO CLEAR THE
CLOUDS OUT. THE LATEST HRRR CONTINUES TO CLEAR CLOUDS OUT OF ALL
AREAS EXCEPT THE SOUTHERN SECTIONS OF THE AREA THIS AFTERNOON. WILL
IGNORE THE MODELS FOR THE MOST PART AND JUST TRY TO ADJUST SKY
GRIDS TO CURRENT SATELLITE. TEMPS WILL NEED SLIGHT ADJUSTMENTS WITH
THE CLOUDS EXPECTED TO HOLD ON IN THE SOUTH AND FULL SUN LIKELY IN
PARTS OF THE NORTH.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
944 PM CST MON DEC 22 2014
.UPDATE...MINOR TWEAKS MADE TO CLOUD COVER AND TEMPERATURE TRENDS
THROUGH THE REMAINDER OF THE EVENING AND OVERNIGHT. ALSO INCREASED
FOG POTENTIAL COVERAGE TO AREAS ACROSS SOUTHEAST ZONES...BASED ON
LATEST HRRR/NAM12/ARW/NMM OUTPUT AND CURRENT T/TD TRENDS ACROSS
THIS REGION. COULD BE SOME LOCALLY DENSE FOG ALONG AND SOUTH OF A
PEARSALL TO PLEASANTON TO CUERO LINE. NO CHANGES MADE TO TOMORROWS
FORECAST...WITH BREEZY AND COLDER CONDITIONS BEHIND THE COLD FRONT.
COULD BE A FEW LOCATIONS THAT BRIEFLY FLIRT WITH WIND ADVISORY
CRITERIA LATE MORNING AND EARLY AFTERNOON. CURRENT FORECAST HAS
GOOD HANDLE ON FALLING TEMPERATURES IN THE AFTERNOON AND PRECIP
CHANCES ACROSS THE NORTH.
&&
.PREV DISCUSSION... /ISSUED 532 PM CST MON DEC 22 2014/
AVIATION...
COMPLEX AVIATION FORECAST OVER THE NEXT 24 TO 30 HOURS. ALL SITES
ARE NOW VFR AND SHOULD REMAIN VFR THROUGH THE EVENING INTO THE
OVERNIGHT HOURS.
BY 06Z MVFR CIGS SHOULD BEGIN TO DEVELOP ACROSS THE I-35
TERMINALS. THE HRRR AND NAM BOTH BRING IFR CIGS AND VISBY INTO
SAT/SSF AFTER MIDNIGHT...BUT FOR NOW HAVE COMPROMISED BETWEEN THE
HIGH RESOLUTION MODELS AND THE GFS AND LEFT CIGS/VISBY AT LOW END
MVFR LEVELS AT SAT/SSF STARTING AT 13Z THROUGH 17Z. THE COLD FRONT
WILL MOVE THROUGH AROUND 12Z TOMORROW MORNING WITH WINDS BEGINNING
TO PICK UP OUT OF THE NORTH BY 17Z GUSTING TO BETWEEN 20 AND 30
KNOTS DURING THE AFTERNOON. CIGS AND VISBY WILL IMPROVE TOMORROW AFTERNOON
WITH THE I-35 SITES RETURNING TO VFR BY TOMORROW EVENING. SOME
ISOLATED LIGHT RAIN SHOWERS WILL BE POSSIBLE BEHIND THE FRONT FOR
A FEW HOURS TOMORROW ACROSS THE HILL COUNTRY AND AUSTIN AREA. HAVE
LEFT THESE OUT OF THE TAF FOR NOW DUE TO THE ISOLATED NATURE AND
FAIRLY LOW CHANCES.
AT DRT...WHICH JUST RECENTLY RETURNED TO VFR CIGS WILL REMAIN SO
UNTIL AFTER MIDNIGHT. AROUND 08Z-10Z FOG MAY DEVELOP DROPPING
VISBY TO MVFR/IFR LEVELS WITH CIGS DROPPINGS TO MVFR. BY 14Z THE
FRONT WILL MOVE THROUGH DRT CAUSING GUSTY NORTH WINDS...CLEARING OUT
THE FOG...AND RAISING CEILINGS TO VFR.
TREADWAY
PREV DISCUSSION... /ISSUED 255 PM CST MON DEC 22 2014/
SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...
LOW CLOUDS HAVE DISSIPATED FROM NEARLY ALL OF THE FORECAST AREA
THIS AFTERNOON...EXCEPT FOR A SMALL PATCH NEAR DEL RIO. MID/HIGH
CLOUDS WILL CONTINUE TO STREAM FROM WEST TO EAST OVER THE REGION.
THERE IS A WIND SHIFT THAT IS BEGINNING TO ENTER THE NORTHWESTERN
CWA. THIS WIND SHIFT IS MOST LIKELY NOT THE TRUE COLD FRONT AS THE
COOLER AIR AND PRESSURE RISES REMAIN WELL TO THE NORTH. HI-RES
MODELS ARE SHOWING THE WINDS ACROSS MOST OF THE CWA RETURNING TO
LIGHT FROM THE EAST/SOUTHEAST OVERNIGHT. THIS COULD LEAD TO FOG
POTENTIAL ACROSS THE SOUTHEASTERN COUNTIES WHERE SURFACE MOISTURE
MAY POOL AHEAD OF THE BOUNDARY. THE NORTH WINDS AND COLD AIR WILL
REACH THE THE CWA TOMORROW MORNING. DAY TIME HIGHS WILL LIKELY BE
JUST BEFORE THE FRONT MOVES THROUGH WITH SLOWLY FALLING OR NEARLY
STEADY TEMPERATURES EXPECTED FOR THE REMAINDER OF THE DAY. HI-RES
MODEL GUIDANCE AS WELL AS THE GLOBAL MODELS CONTINUE TO SUGGEST THE
NORTHERN AND EASTERN ZONES WILL HAVE ENOUGH MOISTURE IN A LAYER
EXTENDING FROM NEAR THE SURFACE TO ABOUT 700 MB FOR SOME SHOWER
ACTIVITY AHEAD AND BEHIND THE BOUNDARY. THERE WILL BE A DRY SLOT TO
THE SOUTHEAST OF THE UPPER LOW THAT MOVES OVER THE AREA THAT WILL
LIMIT MOISTURE IN THE MID-LEVELS AVAILABLE FOR DEEP CONVECTION.
ANY RAIN TOTALS WILL REMAIN LIGHT...GENERALLY LESS THAN 0.15
INCHES. RAIN IS EXPECTED TO END BY TOMORROW NIGHT WITH CLOUDY
SKIES SLOWLY CLEARING. LOWS WILL REACH NEAR FREEZING IN THE HILL
COUNTRY TO UPPER 30S ELSEWHERE.
LONG TERM (WEDNESDAY THROUGH MONDAY)...
CHRISTMAS EVE...CLEAR SKIES AND BREEZY NORTHWEST WINDS WILL BE
PREVAILING FOR MOST OF THE DAY. HIGHS WILL BE ON THE COOL
SIDE...IN THE LOWER 50S TO NEAR 60 DEGREES. CLEAR SKIES AND LIGHT
WINDS WILL LEAD TO DECENT RADIATIONAL COOLING CONDITIONS ACROSS
THE AREA. LOWS CHRISTMAS MORNING WILL RANGE FROM THE UPPER 20S TO
MIDDLE 30S WITH MUCH OF THE AREA AT OR BELOW THE FREEZING MARK.
SOUTH WINDS WILL RETURN AS WELL CHRISTMAS MORNING AND HIGHS WILL
REBOUND INTO THE 60S. THE NEXT UPPER TROUGH WILL PASS THROUGH THE
PLAINS ON FRIDAY AND THIS WILL SEND ANOTHER STRONG COLD FRONT INTO
THE AREA FRIDAY EVENING. LITTLE TO NO PRECIP IS EXPECTED WITH THIS
FRONT BUT THE HILL COUNTRY COULD SEE FREEZING TEMPERATURES ONCE
AGAIN SUNDAY MORNING. SOUTH WINDS RETURN MONDAY AND A SLOW WARMING
TREND WILL BEGIN. THE GFS IS HINTING AT WEAK SHOWERS ASSOCIATED
WITH THE WARM AIR ADVECTION AND WILL FORECAST 20 POPS ACROSS THE
EASTERN ZONES MONDAY.
HAMPSHIRE
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 51 54 38 54 34 / 10 30 - 0 -
AUSTIN BERGSTROM INTL AIRPORT 50 55 37 54 31 / 10 30 - 0 -
NEW BRAUNFELS MUNI AIRPORT 51 58 38 56 33 / 10 30 - - -
BURNET MUNI AIRPORT 49 50 35 51 31 / 20 40 - 0 -
DEL RIO INTL AIRPORT 49 57 37 57 33 / - 10 0 0 0
GEORGETOWN MUNI AIRPORT 49 50 36 52 32 / 20 40 - 0 -
HONDO MUNI AIRPORT 49 62 35 59 32 / - 10 - 0 0
SAN MARCOS MUNI AIRPORT 51 56 37 54 32 / 10 30 - 0 -
LA GRANGE - FAYETTE REGIONAL 53 58 39 55 34 / 10 30 10 - 0
SAN ANTONIO INTL AIRPORT 52 59 38 58 35 / - 20 - 0 0
STINSON MUNI AIRPORT 52 61 38 58 34 / - 20 - - 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...12
SYNOPTIC/GRIDS...76
PUBLIC SERVICE/DATA COLLECTION...30
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
708 PM CST Mon Dec 22 2014
.UPDATE...
Update to issue a High Wind Warning for the Guadalupe Mountains,
and elevations above 6000 feet in the Davis Mountains.
&&
.DISCUSSION...
A fairly potent shortwave trough is translating south/southeastward
through New Mexico early this evening. Although the surface
pressure gradient over the area is not very tight as of 23/00Z,
southwest winds of 35 to 45 mph sustained have already occurred in
the lower elevations of the Guadalupe Mountains. The surface
pressure gradient does not tighten much over the next several hours,
but think much stronger mid level winds associated with the
mentioned shortwave trough will serve to increase winds throughout
the Guadalupe Mountains through 23/06Z.
These stronger mid level winds will also impinge upon the Davis
Mountains this evening, so expect winds to increase in the higher
elevations there. Have decided to issue a High Wind Warning for all
of the Guadalupe Mountains, and the Davis Mountains above 6000
feet. The warning will be in effect until 23/10Z, which will allow
shift later tonight to decide whether the warning should be extended
or not.
Also of concern is precipitation tonight and Tuesday morning, not to
mention precipitation phase. Local radars showed an area of
precipitation moving southeastward through New Mexico along and
behind the above mentioned cold front, with a few lightning strikes
indicated over, and near, northern Lea County. Surface temperatures
were not that cold behind the front, but we should see readings
dropping into the mid 30s by 23/06Z in Lea County in particular.
Radar returns are probably extensive due to low level convergence
along/behind the front, coupled with lift in the mid levels seen on
Water Vapor imagery ahead of a compact shortwave trough over central
New Mexico, and the LFQ of a 140+kt h25 jet. Expect this deep layer
lift to continue, but shift southeastward over the forecast area
overnight. Model soundings, particularly the RUC13 and NAM12, are
indicating rain changing to snow around 23/06Z, with some snow
possibly accumulating over portions of Lea County and the
northwestern Permian Basin. For now, will send an update for the
High Wind Warning, but will address precipitation in another update
later this evening.
&&
.PRELIMINARY POINT TEMPS/POPS...
ANDREWS TX 35 43 28 50 / 60 40 0 0
BIG SPRING TX 39 45 30 52 / 50 40 0 0
CARLSBAD NM 39 47 25 52 / 10 20 0 0
DRYDEN TX 46 52 32 55 / 10 10 0 0
FORT STOCKTON TX 37 44 28 53 / 10 40 0 0
GUADALUPE PASS TX 31 42 24 45 / 10 20 0 0
HOBBS NM 35 45 25 49 / 60 30 0 0
MARFA TX 34 41 15 48 / 10 20 0 0
MIDLAND INTL AIRPORT TX 35 46 26 50 / 30 40 0 0
ODESSA TX 36 48 28 51 / 30 40 0 0
WINK TX 41 48 27 55 / 20 40 0 0
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...HIGH WIND WARNING until 3 AM MST Tuesday FOR THE FOLLOWING
ZONES... Guadalupe Mountains of Eddy County.
TX...HIGH WIND WARNING until 4 AM CST /3 AM MST/ Tuesday FOR THE
FOLLOWING ZONES... Davis/Apache Mountains Area...Guadalupe
Mountains.
&&
$$
05/67
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AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
532 PM CST MON DEC 22 2014
.AVIATION...
COMPLEX AVIATION FORECAST OVER THE NEXT 24 TO 30 HOURS. ALL SITES
ARE NOW VFR AND SHOULD REMAIN VFR THROUGH THE EVENING INTO THE
OVERNIGHT HOURS.
BY 06Z MVFR CIGS SHOULD BEGIN TO DEVELOP ACROSS THE I-35
TERMINALS. THE HRRR AND NAM BOTH BRING IFR CIGS AND VISBY INTO
SAT/SSF AFTER MIDNIGHT...BUT FOR NOW HAVE COMPROMISED BETWEEN THE
HIGH RESOLUTION MODELS AND THE GFS AND LEFT CIGS/VISBY AT LOW END
MVFR LEVELS AT SAT/SSF STARTING AT 13Z THROUGH 17Z. THE COLD FRONT
WILL MOVE THROUGH AROUND 12Z TOMORROW MORNING WITH WINDS BEGINNING
TO PICK UP OUT OF THE NORTH BY 17Z GUSTING TO BETWEEN 20 AND 30
KNOTS DURING THE AFTERNOON. CIGS AND VISBY WILL IMPROVE TOMORROW AFTERNOON
WITH THE I-35 SITES RETURNING TO VFR BY TOMORROW EVENING. SOME
ISOLATED LIGHT RAIN SHOWERS WILL BE POSSIBLE BEHIND THE FRONT FOR
A FEW HOURS TOMORROW ACROSS THE HILL COUNTRY AND AUSTIN AREA. HAVE
LEFT THESE OUT OF THE TAF FOR NOW DUE TO THE ISOLATED NATURE AND
FAIRLY LOW CHANCES.
AT DRT...WHICH JUST RECENTLY RETURNED TO VFR CIGS WILL REMAIN SO
UNTIL AFTER MIDNIGHT. AROUND 08Z-10Z FOG MAY DEVELOP DROPPING
VISBY TO MVFR/IFR LEVELS WITH CIGS DROPPINGS TO MVFR. BY 14Z THE
FRONT WILL MOVE THROUGH DRT CAUSING GUSTY NORTH WINDS...CLEARING OUT
THE FOG...AND RAISING CEILINGS TO VFR.
TREADWAY
&&
.PREV DISCUSSION... /ISSUED 255 PM CST MON DEC 22 2014/
SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...
LOW CLOUDS HAVE DISSIPATED FROM NEARLY ALL OF THE FORECAST AREA
THIS AFTERNOON...EXCEPT FOR A SMALL PATCH NEAR DEL RIO. MID/HIGH
CLOUDS WILL CONTINUE TO STREAM FROM WEST TO EAST OVER THE REGION.
THERE IS A WIND SHIFT THAT IS BEGINNING TO ENTER THE NORTHWESTERN
CWA. THIS WIND SHIFT IS MOST LIKELY NOT THE TRUE COLD FRONT AS THE
COOLER AIR AND PRESSURE RISES REMAIN WELL TO THE NORTH. HI-RES
MODELS ARE SHOWING THE WINDS ACROSS MOST OF THE CWA RETURNING TO
LIGHT FROM THE EAST/SOUTHEAST OVERNIGHT. THIS COULD LEAD TO FOG
POTENTIAL ACROSS THE SOUTHEASTERN COUNTIES WHERE SURFACE MOISTURE
MAY POOL AHEAD OF THE BOUNDARY. THE NORTH WINDS AND COLD AIR WILL
REACH THE THE CWA TOMORROW MORNING. DAY TIME HIGHS WILL LIKELY BE
JUST BEFORE THE FRONT MOVES THROUGH WITH SLOWLY FALLING OR NEARLY
STEADY TEMPERATURES EXPECTED FOR THE REMAINDER OF THE DAY. HI-RES
MODEL GUIDANCE AS WELL AS THE GLOBAL MODELS CONTINUE TO SUGGEST THE
NORTHERN AND EASTERN ZONES WILL HAVE ENOUGH MOISTURE IN A LAYER
EXTENDING FROM NEAR THE SURFACE TO ABOUT 700 MB FOR SOME SHOWER
ACTIVITY AHEAD AND BEHIND THE BOUNDARY. THERE WILL BE A DRY SLOT TO
THE SOUTHEAST OF THE UPPER LOW THAT MOVES OVER THE AREA THAT WILL
LIMIT MOISTURE IN THE MID-LEVELS AVAILABLE FOR DEEP CONVECTION.
ANY RAIN TOTALS WILL REMAIN LIGHT...GENERALLY LESS THAN 0.15
INCHES. RAIN IS EXPECTED TO END BY TOMORROW NIGHT WITH CLOUDY
SKIES SLOWLY CLEARING. LOWS WILL REACH NEAR FREEZING IN THE HILL
COUNTRY TO UPPER 30S ELSEWHERE.
LONG TERM (WEDNESDAY THROUGH MONDAY)...
CHRISTMAS EVE...CLEAR SKIES AND BREEZY NORTHWEST WINDS WILL BE
PREVAILING FOR MOST OF THE DAY. HIGHS WILL BE ON THE COOL
SIDE...IN THE LOWER 50S TO NEAR 60 DEGREES. CLEAR SKIES AND LIGHT
WINDS WILL LEAD TO DECENT RADIATIONAL COOLING CONDITIONS ACROSS
THE AREA. LOWS CHRISTMAS MORNING WILL RANGE FROM THE UPPER 20S TO
MIDDLE 30S WITH MUCH OF THE AREA AT OR BELOW THE FREEZING MARK.
SOUTH WINDS WILL RETURN AS WELL CHRISTMAS MORNING AND HIGHS WILL
REBOUND INTO THE 60S. THE NEXT UPPER TROUGH WILL PASS THROUGH THE
PLAINS ON FRIDAY AND THIS WILL SEND ANOTHER STRONG COLD FRONT INTO
THE AREA FRIDAY EVENING. LITTLE TO NO PRECIP IS EXPECTED WITH THIS
FRONT BUT THE HILL COUNTRY COULD SEE FREEZING TEMPERATURES ONCE
AGAIN SUNDAY MORNING. SOUTH WINDS RETURN MONDAY AND A SLOW WARMING
TREND WILL BEGIN. THE GFS IS HINTING AT WEAK SHOWERS ASSOCIATED
WITH THE WARM AIR ADVECTION AND WILL FORECAST 20 POPS ACROSS THE
EASTERN ZONES MONDAY.
HAMPSHIRE
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 51 54 38 54 34 / 10 30 - 0 -
AUSTIN BERGSTROM INTL AIRPORT 50 55 37 54 31 / 10 30 - 0 -
NEW BRAUNFELS MUNI AIRPORT 51 58 38 56 33 / 10 30 - - -
BURNET MUNI AIRPORT 49 52 35 51 31 / 20 40 - 0 -
DEL RIO INTL AIRPORT 49 58 37 57 33 / - 10 0 0 0
GEORGETOWN MUNI AIRPORT 49 52 36 52 32 / 20 40 - 0 -
HONDO MUNI AIRPORT 49 62 35 59 32 / - 10 - 0 0
SAN MARCOS MUNI AIRPORT 51 56 37 54 32 / 10 30 - 0 -
LA GRANGE - FAYETTE REGIONAL 53 58 39 55 34 / 10 30 10 - 0
SAN ANTONIO INTL AIRPORT 52 59 38 58 35 / - 20 - 0 0
STINSON MUNI AIRPORT 52 61 38 58 34 / - 20 - - 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...12
SYNOPTIC/GRIDS...76
PUBLIC SERVICE/DATA COLLECTION...30
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1150 AM CST SUN DEC 21 2014
.AVIATION...
STRATUS CLEARED KCDS EARLIER WITH VFR CONDITIONS EXPECTED TO
PREVAIL AT ALL TAF SITES THROUGH THE PERIOD. SFC LEE TROUGH
DEVELOPING OVER ERN NM WILL KEEP WESTERLY WINDS UP THIS AFTERNOON.
WINDS VEER OVERNIGHT AS TROUGH MOVES EAST.
&&
PREV DISCUSSION... /ISSUED 434 AM CST SUN DEC 21 2014/
SHORT TERM...
SURFACE TROUGH WAS FOUND PUSHING ACROSS OUR WESTERN COLUMN OF
COUNTIES AT 09Z AHEAD OF MUCH LOWER DEWPOINTS. EAST OF THIS TROUGH
IS WHERE STRATUS HAS BEEN ANCHORED SINCE EARLY LAST NIGHT...
HOWEVER UNLIKE RECENT DAYS WE EXPECT THESE LOW CLOUDS TO QUICKLY
ERODE FROM W-E AS THE SURFACE TROUGH MOTORS EAST IN RESPONSE TO A
S/W TROUGH NOW ENTERING THE WESTERN TX PANHANDLE. FOG-WISE...AREA
CAMERAS AND METARS AT 09Z SHOW THE LOWEST VISBYS OF 1/2 TO 1 MILE
CONFINED TO A RELATIVELY SMALL AREA FROM SEMINOLE TO LUBBOCK TO
LAMESA. HRRR HAS HIGHLIGHTED THIS AREA FOR FOG FOR SEVERAL RUNS...
BUT ITS VISBYS REMAIN TOO PESSIMISTIC COMPARED TO GROUND TRUTH AND
THIS REDUCES CONFIDENCE IN DENSE FOG DEVELOPMENT AND ANY NEED FOR
A HEADLINE. WILL KEEP MENTION OF LOCALLY DENSE FOG IN NOWCASTS...
BUT EVEN THIS WINDOW IS SHRINKING AS THE SURFACE TROUGH CONTINUES
EDGING CLOSER WITH IMPROVING VISBYS.
SUBSIDENCE BEHIND THE AFOREMENTIONED S/W TROUGH WILL HELP RID ANY
LINGERING STRATUS FROM THE ROLLING PLAINS BY MIDDAY WHILE ALSO
SERVING TO BOOST 1000-500MB THICKNESSES TO NEARLY 561 DAM. OPTED
FOR THE BCCONSALL WITH HIGH TEMPS TODAY AS REMAINING GUIDANCE
LOOKED TOO COOL FOR THIS PATTERN OF DEEP WLY FLOW AND DRY
DOWNSLOPE WINDS. THESE MILD THICKNESS VALUES FALL VERY LITTLE
TONIGHT THANKS TO AN IMPRESSIVE LL THERMAL RIDGE MIGRATING SOUTH
AHEAD OF MONDAY/S COLD FRONT...SO MIN TEMPS WERE BOOSTED 2 TO 5
DEGREES. THESE SEEMINGLY MILD LOW TEMPS MAY STILL PROVE TOO COOL
GIVEN WEST WINDS OVERNIGHT OF 10 TO 15 MPH.
LONG TERM...
COMPLICATED LONG TERM FORECAST FOR NEXT WEEK AS A SERIES OF STORM
SYSTEMS WILL IMPACT THE AREA. FIRST ONE WILL BE MONDAY NIGHT INTO
TUESDAY MORNING. A WEAK COLD FRONT WILL PUSH INTO THE AREA DURING
THE DAY MONDAY WITH SOME DIFFERENCES ON HOW FAR SOUTH IT WILL MAKE
IT INTO THE FORECAST AREA. FRONTAL LOCATION IS WAFFLING NORTHWEST
TO SOUTHEAST ACROSS THE FORECAST AREA DEPENDING ON THE MODEL AND
THE TIME OF THE RUN. HOWEVER...GENERAL CONSENSUS IS FOR THE FRONT
TO MAKE IT INTO ALL BUT THE FAR SOUTHWESTERN COUNTIES BY MONDAY
AFTERNOON. NORTH WIND WILL NOT BE PARTICULARLY STRONG BEHIND THE
FRONT BUT ENOUGH THIS WILL SET UP ABOUT A 10-14 DEGREE TEMPERATURE
GRADIENT FROM NORTH TO SOUTH ACROSS THE REGION. ALSO TAKING PLACE
THROUGH THE DAY...A CLOSED LOW ALOFT WILL MOVE ACROSS THE NORTHERN
PLAINS TOWARDS THE GREAT LAKES. A STRONG 140-160KT JET WILL MOVE
SOUTHWARD ON THE WESTERN EDGE OF THE LOW HELPING TO DEEPEN THE
TROUGH ASSOCIATED WITH THE CLOSED LOW AS THE TROF AXIS IS JUST
WEST OF THE REGION. A POCKET OF MID-LEVEL MOISTURE WILL ARRIVE AT
THE SAME TIME THE TROF IS MOVING OVERHEAD WHICH WILL BE JUST
ENOUGH FOR PRECIPITATION TO DEVELOP. UNCERTAINTY STILL REMAIN ON
HOW MUCH MOISTURE WILL BE AVAILABLE BUT MODELS CONTINUE TO BREAK
OUT PRECIPITATION ACROSS THE FORECAST AREA AFTER MIDNIGHT TUESDAY
MORNING. MODEL SOUNDINGS AND CROSS SECTIONS SHOW THE COLUMN WILL
MOISTEN FROM THE TOP DOWN WITH THE NORTHWESTERN SOUTH PLAINS
HAVING THE BEST CHANCE AT REACHING SATURATION. STRONG LIFT
ASSOCIATED WITH THE APPROACHING TROUGH WILL HELP TO COOL THE COLUMN
SO THAT WE WILL SEE A TRANSITION FROM RAIN TO SNOW THROUGH THE
EARLY MORNING HOURS. SUCH STRONG LIFT AND A BIT OF ELEVATED
INSTABILITY AROUND 06Z MAY BE ENOUGH TO RESULT IN SOME HEAVIER
PRECIPITATION ELEMENTS IN A BROAD AREA OF STRATIFORM
PRECIPITATION. PRECIPITATION WILL START OFF AS RAIN AND THEN START
A TRANSITION FROM NORTHWEST TO SOUTHEAST TO A RAIN/SNOW MIX...THEN
ALL SNOW. SNOW LINE WILL PROBABLY MAKE IT TO THE EDGE OF THE
CAPROCK AND AS FAR SOUTH AS A LUBBOCK TO DENVER CITY LINE LEAVING
THE ROLLING PLAINS AND FAR SOUTHERN SOUTH PLAINS AS ALL RAIN.
ACCUMULATIONS ARE EXPECTED TO REMAIN BELOW ONE INCH BUT A FEW
LOCATIONS ACROSS THE NORTHWESTERN SOUTH PLAINS COULD BUMP UP CLOSE
TO AN INCH.
PRECIPITATION WILL COME TO A FAIRLY FAST END BY 12Z TUESDAY MORNING
AS THE TROF AXIS MOVES EAST OF THE AREA AND THE BEST MID-LEVEL
MOISTURE SHIFTS EAST OF THE REGION. BREEZY NORTHERLY WIND WILL BE
IN PLACE THROUGH THE DAY TUESDAY WHICH WILL KEEP HIGH TEMPERATURES
IN THE LOW 40S ON THE CAPROCK TO NEAR 50 ACROSS THE ROLLING
PLAINS. COMBINED WITH THE STRONG NORTH WIND...WIND CHILL READINGS
WILL BE PRETTY COLD WITH SOME MID 20 F READINGS THROUGHOUT THE
DAY. NORTHWEST FLOW ALOFT ON WEDNESDAY WILL RESULT IN A DEEPENING
LEE SURFACE TROF HELPING TO MODERATE TEMPERATURES BACK INTO THE
LOW/MID 50S FOR CHRISTMAS EVE DAY. CHRISTMAS DAY STILL APPEARS TO
BE BREEZY WITH THE POSSIBILITY OF A BROWN CHRISTMAS...MODELS
CONTINUE TO SLOWLY CREEP WIND SPEEDS UP ACROSS THE REGION.
HOWEVER...MODELS NOW HAVE ZONAL FLOW ACROSS THE AREA WHICH DOES
NOT FAVOR WIND SPEEDS AS STRONG AS WAS BELIEVED 2-3 DAYS AGO. LEE
SURFACE TROUGH WILL DEEPEN THROUGH THE DAY WEDNESDAY RESULTING IN
WESTERLY SURFACE WIND 15-25 MPH WITH GUSTS UP TO 35 MPH. THIS WILL
BOOST TEMPERATURES INTO THE MID TO UPPER 60S ACROSS THE REGION
MAKING FOR A WARMER THAN NORMAL CHRISTMAS. HELD OFF MENTIONING ANY
KIND OF BLOWING DUST IN THE GRIDS UNTIL WE GET CLOSER AND HAVE A
BETTER HANDLE ON WHAT THE PEAK WIND SPEEDS WILL BE.
AFTER CHRISTMAS AND HEADING INTO THE HOLIDAY WEEKEND...A COLD
FRONT WILL ARRIVE EARLY FRIDAY MORNING BRINGING TEMPERATURES BACK
DOWN TO NEAR OR JUST BELOW NORMAL FOR FRIDAY AND SATURDAY. THIS
PASSAGE WILL BE DRY AS THE BEST LOW-LEVEL MOISTURE WILL BE WELL
SOUTH OF THE AREA. A BIT OF A WARMUP WILL ENSUE AT THE END OF THE
WEEKEND AS SURFACE FLOW VEERS BACK TO THE SOUTH TO SOUTHWEST
SUNDAY AFTERNOON.
JORDAN
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 34 56 25 41 22 / 0 0 50 0 0
TULIA 35 56 28 42 24 / 0 0 50 0 0
PLAINVIEW 36 58 29 42 25 / 0 0 50 10 0
LEVELLAND 37 63 30 44 26 / 0 0 50 10 0
LUBBOCK 38 61 31 44 26 / 0 0 50 10 0
DENVER CITY 39 68 32 46 27 / 0 0 50 10 0
BROWNFIELD 38 67 32 45 27 / 0 0 50 10 0
CHILDRESS 37 59 35 48 29 / 0 0 30 10 0
SPUR 39 63 36 48 30 / 0 0 40 10 0
ASPERMONT 42 67 38 51 31 / 0 0 40 10 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93/14/24
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1102 AM CST SUN DEC 21 2014
.AVIATION...
IFR/MVFR CIGS CONTINUE TO ENCOMPASS SOUTH CENTRAL TEXAS. KAUS AND
KSAT HAVE LIFTED INTO MVFR WHILE KSSF AND KDRT CONTINUE WITH IFR
CONDITIONS. THESE TWO SITES SHOULD IMPROVE WITHIN THE NEXT HOUR
OR TWO. MVFR WILL CONTINUE FOR MOST OF THE REMAINDER OF THE
AFTERNOON AND EVENING. MODELS SEEM TO BE TOO OPTIMISTIC WITH
LIFTING THE CIGS TO 5KFT AND WILL KEEP HIGHER MVFR PREVAILING.
SHOULD SEE CIGS LOWER INTO LOW MVFR THEN POSSIBLY IFR ONCE AGAIN
TOMORROW MORNING. THE WIND COMPONENT WILL BECOME MORE
SOUTHWESTERLY TOMORROW WHICH SHOULD BEGIN TO SCATTER THINGS OUT A
BIT BETTER.
HAMPSHIRE
&&
.PREV DISCUSSION... /ISSUED 950 AM CST SUN DEC 21 2014/
UPDATE...
OVERCAST SKIES CONTINUE ACROSS ALL OF SOUTH CENTRAL TEXAS.
OVERRUNNING CONDITIONS WILL CONTINUE TODAY AS SURFACE RIDGE AXIS
ALONG THE COASTAL PLAINS SLOWLY SHIFTS EAST AND RETURN FLOW
DEVELOPS AT THE SURFACE AND MID LEVELS. THIS OVERRUNNING WILL ALLOW FOR
SOME LIGHT PATCHY DRIZZLE THE NEXT HOUR OR SO IN A FEW SPOTS BUT
NOT HEAVY ENOUGH TO MENTION IN THE FORECAST AT THIS TIME. MODELS
SHOW THE OVERRUNNING CLOUDS WILL CONTINUE OVER THE EASTERN HALF OF
THE CWA ALL DAY WHILE THINNER MOISTURE OUT WEST WILL MIX OUT BY
THE AFTERNOON GIVING WAY TO SOME SUNSHINE. LATEST HRRR MODELS
SHOWS THIS AS WELL. MADE SOME MINOR ADJUSTMENTS TO THE GRIDS BUT
OVERALL CURRENT FORECAST TREND IS GOOD.
PREV DISCUSSION... /ISSUED 535 AM CST SUN DEC 21 2014/
AVIATION.../12Z TAF CYCLE/
MVFR PREVAILS ACROSS CENTRAL TAF SITES WITH STRATUS OVC015 CIGS ON
AVERAGE WITH LOWER IFR CIGS AT KDRT NEAR 600FT AS OF 12Z. EXPECT
KDRT TO IMPROVE THROUGH LATE MORNING/AFT TO VFR. CENTRAL SITES WILL
BE TRICKY WITH MODEL GUIDANCE IN DISAGREEMENT ON WHETHER VFR
CONDITIONS WILL RETURN FEEL STRATUS DECK WILL ERODE IN WEST TEXAS
AND WITH WEAK S/SW FLOW WILL HELP MORE CLEARING TOWARDS KSAT/KSSF
THAN YESTERDAY BUT IT WILL BE CLOSE. FEEL KAUS HAS LEAST CHANCE OF
GOING VFR WITH HIGH END MVFR THROUGH THE AFTERNOON. EXPECT CENTRAL
SITES TO FALL BACK TO LOW MVFR TO POSSIBLY IFR OVERNIGHT. HAVE
FOLLOWED MORE OF NAM/RAP CONSISTENCY FOR KDRT WITH MVFR POSSIBLY
RETURNING OVERNIGHT AS WELL. MUCH QUICKER CLEARING EXPECTED MONDAY
WITH VFR LIKELY FOR ALL SITES BY NOON.
SURFACE WINDS WILL BE S/SW AT 10 KT OR LESS THROUGH THE AFTERNOON
AND OVERNIGHT. /ALLEN/
PREV DISCUSSION... /ISSUED 357 AM CST SUN DEC 21 2014/
SHORT TERM (TODAY THROUGH MONDAY)...
PATCHY FOG HAS DEVELOPED IN SOME SPOTS AND WILL MAINTAIN MENTION
THROUGH MID MORNING. AN UPPER LEVEL TROUGH DEVELOPING OVER THE
CENTRAL STATES GETS AN ENHANCEMENT FROM A COUPLE SHORT-WAVES
MOVING ACROSS TEXAS AND A STRONGER SHORT-WAVE CURRENTLY MOVING
INTO THE PACIFIC NORTHWEST. WEAK ISENTROPIC LIFT MAINTAINS MOSTLY
CLOUDY SKIES AND NEAR AVERAGE TEMPERATURES TODAY. A SOUTHWESTERLY
LOWER LEVEL FLOW DEVELOPS ON MONDAY AS SURFACE LOW STRENGTHENS IN
THE PLAINS LEADING TO WELL ABOVE AVERAGE TEMPERATURES AND WARMEST
OF THE NEXT WEEK AS CLOUDS ERODE.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...
THE ABOVE MENTIONED PACIFIC NORTHWEST SHORT-WAVE FORCES A STRONG
COLD FRONT SOUTH ACROSS SOUTH CENTRAL TEXAS LATE MONDAY NIGHT INTO
EARLY TUESDAY. THEN THE UPPER LEVEL TROUGH MOVES THROUGH LATER ON
TUESDAY. SOME LIGHT RAIN SHOWERS ARE POSSIBLE ACROSS EASTERN AREAS
WITH THE FRONT TUESDAY MORNING. THERE MAY BE A FEW SPRINKLES WITH
THE UPPER LEVEL TROUGH. HOWEVER...HAVE NOT MENTIONED AS THE LOWER
LEVELS WILL BE DRYING. A STRONG PRESSURE GRADIENT CREATES BREEZY
CONDITIONS WITH GUSTS UP TO 30 MPH TUESDAY. TEMPERATURES FALL BACK
TO BELOW AVERAGE FOR TUESDAY INTO WEDNESDAY. SOME LOW LYING SPOTS
IN THE HILL COUNTRY AND ALONG THE ESCARPMENT WILL DROP TO FREEZING
WEDNESDAY AND CHRISTMAS MORNINGS AS WINDS DECOUPLE SOMEWHAT AS
SURFACE HIGH MOVES ACROSS OUR AREA. THE HIGH MOVES OFF TO THE EAST
WITH SOUTHERLY LOWER FLOW WARMING TEMPERATURES BACK TO ABOVE
AVERAGE FOR CHRISTMAS AFTERNOON. ANOTHER STRONG COLD FRONT MOVES
ACROSS THE AREA FRIDAY LEADING TO BELOW AVERAGE TEMPERATURES FOR
NEXT WEEKEND. NO RAIN EXPECTED WITH THIS FRONT DUE TO LIMITED
MOISTURE. BEYOND THIS FORECAST PERIOD...SOME MODELS ARE SHOWING
EVEN COLDER AIR FOR NEXT WEEK IN THE DAYS BEFORE THE NEW YEAR.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 60 51 71 50 58 / - - - 10 10
AUSTIN BERGSTROM INTL AIRPORT 60 48 71 49 59 / - - - 10 10
NEW BRAUNFELS MUNI AIRPORT 61 50 73 51 60 / - - - 10 10
BURNET MUNI AIRPORT 58 47 72 46 55 / - - - 10 10
DEL RIO INTL AIRPORT 64 45 75 49 60 / - - 0 - 10
GEORGETOWN MUNI AIRPORT 59 49 71 48 56 / - - - 10 10
HONDO MUNI AIRPORT 62 48 74 47 61 / - - 0 - -
SAN MARCOS MUNI AIRPORT 61 49 71 50 59 / - - - 10 10
LA GRANGE - FAYETTE REGIONAL 62 51 73 54 58 / - 10 - 10 20
SAN ANTONIO INTL AIRPORT 61 51 73 50 61 / - - 0 10 10
STINSON MUNI AIRPORT 62 50 74 50 61 / - - 0 10 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...29
SYNOPTIC/GRIDS...09
PUBLIC SERVICE/DATA COLLECTION...33
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
950 AM CST SUN DEC 21 2014
.UPDATE...
OVERCAST SKIES CONTINUE ACROSS ALL OF SOUTH CENTRAL TEXAS.
OVERRUNNING CONDITIONS WILL CONTINUE TODAY AS SURFACE RIDGE AXIS
ALONG THE COASTAL PLAINS SLOWLY SHIFTS EAST AND RETURN FLOW
DEVELOPS AT THE SURFACE AND MID LEVELS. THIS OVERRUNNING WILL ALLOW FOR
SOME LIGHT PATCHY DRIZZLE THE NEXT HOUR OR SO IN A FEW SPOTS BUT
NOT HEAVY ENOUGH TO MENTION IN THE FORECAST AT THIS TIME. MODELS
SHOW THE OVERRUNNING CLOUDS WILL CONTINUE OVER THE EASTERN HALF OF
THE CWA ALL DAY WHILE THINNER MOISTURE OUT WEST WILL MIX OUT BY
THE AFTERNOON GIVING WAY TO SOME SUNSHINE. LATEST HRRR MODELS
SHOWS THIS AS WELL. MADE SOME MINOR ADJUSTMENTS TO THE GRIDS BUT
OVERALL CURRENT FORECAST TREND IS GOOD.
&&
.PREV DISCUSSION... /ISSUED 535 AM CST SUN DEC 21 2014/
AVIATION.../12Z TAF CYCLE/
MVFR PREVAILS ACROSS CENTRAL TAF SITES WITH STRATUS OVC015 CIGS ON
AVERAGE WITH LOWER IFR CIGS AT KDRT NEAR 600FT AS OF 12Z. EXPECT
KDRT TO IMPROVE THROUGH LATE MORNING/AFT TO VFR. CENTRAL SITES WILL
BE TRICKY WITH MODEL GUIDANCE IN DISAGREEMENT ON WHETHER VFR
CONDITIONS WILL RETURN FEEL STRATUS DECK WILL ERODE IN WEST TEXAS
AND WITH WEAK S/SW FLOW WILL HELP MORE CLEARING TOWARDS KSAT/KSSF
THAN YESTERDAY BUT IT WILL BE CLOSE. FEEL KAUS HAS LEAST CHANCE OF
GOING VFR WITH HIGH END MVFR THROUGH THE AFTERNOON. EXPECT CENTRAL
SITES TO FALL BACK TO LOW MVFR TO POSSIBLY IFR OVERNIGHT. HAVE
FOLLOWED MORE OF NAM/RAP CONSISTENCY FOR KDRT WITH MVFR POSSIBLY
RETURNING OVERNIGHT AS WELL. MUCH QUICKER CLEARING EXPECTED MONDAY
WITH VFR LIKELY FOR ALL SITES BY NOON.
SURFACE WINDS WILL BE S/SW AT 10 KT OR LESS THROUGH THE AFTERNOON
AND OVERNIGHT. /ALLEN/
PREV DISCUSSION... /ISSUED 357 AM CST SUN DEC 21 2014/
SHORT TERM (TODAY THROUGH MONDAY)...
PATCHY FOG HAS DEVELOPED IN SOME SPOTS AND WILL MAINTAIN MENTION
THROUGH MID MORNING. AN UPPER LEVEL TROUGH DEVELOPING OVER THE
CENTRAL STATES GETS AN ENHANCEMENT FROM A COUPLE SHORT-WAVES
MOVING ACROSS TEXAS AND A STRONGER SHORT-WAVE CURRENTLY MOVING
INTO THE PACIFIC NORTHWEST. WEAK ISENTROPIC LIFT MAINTAINS MOSTLY
CLOUDY SKIES AND NEAR AVERAGE TEMPERATURES TODAY. A SOUTHWESTERLY
LOWER LEVEL FLOW DEVELOPS ON MONDAY AS SURFACE LOW STRENGTHENS IN
THE PLAINS LEADING TO WELL ABOVE AVERAGE TEMPERATURES AND WARMEST
OF THE NEXT WEEK AS CLOUDS ERODE.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...
THE ABOVE MENTIONED PACIFIC NORTHWEST SHORT-WAVE FORCES A STRONG
COLD FRONT SOUTH ACROSS SOUTH CENTRAL TEXAS LATE MONDAY NIGHT INTO
EARLY TUESDAY. THEN THE UPPER LEVEL TROUGH MOVES THROUGH LATER ON
TUESDAY. SOME LIGHT RAIN SHOWERS ARE POSSIBLE ACROSS EASTERN AREAS
WITH THE FRONT TUESDAY MORNING. THERE MAY BE A FEW SPRINKLES WITH
THE UPPER LEVEL TROUGH. HOWEVER...HAVE NOT MENTIONED AS THE LOWER
LEVELS WILL BE DRYING. A STRONG PRESSURE GRADIENT CREATES BREEZY
CONDITIONS WITH GUSTS UP TO 30 MPH TUESDAY. TEMPERATURES FALL BACK
TO BELOW AVERAGE FOR TUESDAY INTO WEDNESDAY. SOME LOW LYING SPOTS
IN THE HILL COUNTRY AND ALONG THE ESCARPMENT WILL DROP TO FREEZING
WEDNESDAY AND CHRISTMAS MORNINGS AS WINDS DECOUPLE SOMEWHAT AS
SURFACE HIGH MOVES ACROSS OUR AREA. THE HIGH MOVES OFF TO THE EAST
WITH SOUTHERLY LOWER FLOW WARMING TEMPERATURES BACK TO ABOVE
AVERAGE FOR CHRISTMAS AFTERNOON. ANOTHER STRONG COLD FRONT MOVES
ACROSS THE AREA FRIDAY LEADING TO BELOW AVERAGE TEMPERATURES FOR
NEXT WEEKEND. NO RAIN EXPECTED WITH THIS FRONT DUE TO LIMITED
MOISTURE. BEYOND THIS FORECAST PERIOD...SOME MODELS ARE SHOWING
EVEN COLDER AIR FOR NEXT WEEK IN THE DAYS BEFORE THE NEW YEAR.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 60 51 71 50 58 / - - - 10 10
AUSTIN BERGSTROM INTL AIRPORT 60 48 71 49 59 / - - - 10 10
NEW BRAUNFELS MUNI AIRPORT 61 50 73 51 60 / - - - 10 10
BURNET MUNI AIRPORT 58 47 72 46 55 / - - - 10 10
DEL RIO INTL AIRPORT 64 45 75 49 60 / - - 0 - 10
GEORGETOWN MUNI AIRPORT 59 49 71 48 56 / - - - 10 10
HONDO MUNI AIRPORT 62 48 74 47 61 / - - 0 - -
SAN MARCOS MUNI AIRPORT 61 49 71 50 59 / - - - 10 10
LA GRANGE - FAYETTE REGIONAL 62 51 73 54 58 / - 10 - 10 20
SAN ANTONIO INTL AIRPORT 61 51 73 50 61 / - - 0 10 10
STINSON MUNI AIRPORT 62 50 74 50 61 / - - 0 10 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...29
SYNOPTIC/GRIDS...09
PUBLIC SERVICE/DATA COLLECTION...33
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
537 AM CST SUN DEC 21 2014
.AVIATION...
BACK EDGE OF IFR STRATUS RECENTLY EXITED PVW AND WILL DO THE
SAME AT LBB BEFORE 14Z AS DRIER WSW WINDS ARRIVE AND RESTORE
VFR LEVELS. VISBYS ARE ALSO ON THE REBOUND...THOUGH THESE MAY
STILL FALL TO 1SM OR LESS BEFORE 14Z. DURATION AND UNCERTAINTY
OF THIS SCENARIO PRECLUDES A TEMPO MENTION AT THIS TIME.
TIMING THE DRIER AIR AND VFR CONDITIONS INTO CDS STILL YIELDS A
17Z TARGET TIME FROM EARLIER TAFS. UNTIL THEN...MVFR CIGS SHOULD
PREVAIL WITH JUST FEW-SCT CLOUDS AOB 1K FEET.
&&
.PREV DISCUSSION... /ISSUED 434 AM CST SUN DEC 21 2014/
SHORT TERM...
SURFACE TROUGH WAS FOUND PUSHING ACROSS OUR WESTERN COLUMN OF
COUNTIES AT 09Z AHEAD OF MUCH LOWER DEWPOINTS. EAST OF THIS TROUGH
IS WHERE STRATUS HAS BEEN ANCHORED SINCE EARLY LAST NIGHT...
HOWEVER UNLIKE RECENT DAYS WE EXPECT THESE LOW CLOUDS TO QUICKLY
ERODE FROM W-E AS THE SURFACE TROUGH MOTORS EAST IN RESPONSE TO A
S/W TROUGH NOW ENTERING THE WESTERN TX PANHANDLE. FOG-WISE...AREA
CAMERAS AND METARS AT 09Z SHOW THE LOWEST VISBYS OF 1/2 TO 1 MILE
CONFINED TO A RELATIVELY SMALL AREA FROM SEMINOLE TO LUBBOCK TO
LAMESA. HRRR HAS HIGHLIGHTED THIS AREA FOR FOG FOR SEVERAL RUNS...
BUT ITS VISBYS REMAIN TOO PESSIMISTIC COMPARED TO GROUND TRUTH AND
THIS REDUCES CONFIDENCE IN DENSE FOG DEVELOPMENT AND ANY NEED FOR
A HEADLINE. WILL KEEP MENTION OF LOCALLY DENSE FOG IN NOWCASTS...
BUT EVEN THIS WINDOW IS SHRINKING AS THE SURFACE TROUGH CONTINUES
EDGING CLOSER WITH IMPROVING VISBYS.
SUBSIDENCE BEHIND THE AFOREMENTIONED S/W TROUGH WILL HELP RID ANY
LINGERING STRATUS FROM THE ROLLING PLAINS BY MIDDAY WHILE ALSO
SERVING TO BOOST 1000-500MB THICKNESSES TO NEARLY 561 DAM. OPTED
FOR THE BCCONSALL WITH HIGH TEMPS TODAY AS REMAINING GUIDANCE
LOOKED TOO COOL FOR THIS PATTERN OF DEEP WLY FLOW AND DRY
DOWNSLOPE WINDS. THESE MILD THICKNESS VALUES FALL VERY LITTLE
TONIGHT THANKS TO AN IMPRESSIVE LL THERMAL RIDGE MIGRATING SOUTH
AHEAD OF MONDAY/S COLD FRONT...SO MIN TEMPS WERE BOOSTED 2 TO 5
DEGREES. THESE SEEMINGLY MILD LOW TEMPS MAY STILL PROVE TOO COOL
GIVEN WEST WINDS OVERNIGHT OF 10 TO 15 MPH.
LONG TERM...
COMPLICATED LONG TERM FORECAST FOR NEXT WEEK AS A SERIES OF STORM
SYSTEMS WILL IMPACT THE AREA. FIRST ONE WILL BE MONDAY NIGHT INTO
TUESDAY MORNING. A WEAK COLD FRONT WILL PUSH INTO THE AREA DURING
THE DAY MONDAY WITH SOME DIFFERENCES ON HOW FAR SOUTH IT WILL MAKE
IT INTO THE FORECAST AREA. FRONTAL LOCATION IS WAFFLING NORTHWEST
TO SOUTHEAST ACROSS THE FORECAST AREA DEPENDING ON THE MODEL AND
THE TIME OF THE RUN. HOWEVER...GENERAL CONSENSUS IS FOR THE FRONT
TO MAKE IT INTO ALL BUT THE FAR SOUTHWESTERN COUNTIES BY MONDAY
AFTERNOON. NORTH WIND WILL NOT BE PARTICULARLY STRONG BEHIND THE
FRONT BUT ENOUGH THIS WILL SET UP ABOUT A 10-14 DEGREE TEMPERATURE
GRADIENT FROM NORTH TO SOUTH ACROSS THE REGION. ALSO TAKING PLACE
THROUGH THE DAY...A CLOSED LOW ALOFT WILL MOVE ACROSS THE NORTHERN
PLAINS TOWARDS THE GREAT LAKES. A STRONG 140-160KT JET WILL MOVE
SOUTHWARD ON THE WESTERN EDGE OF THE LOW HELPING TO DEEPEN THE
TROUGH ASSOCIATED WITH THE CLOSED LOW AS THE TROF AXIS IS JUST
WEST OF THE REGION. A POCKET OF MID-LEVEL MOISTURE WILL ARRIVE AT
THE SAME TIME THE TROF IS MOVING OVERHEAD WHICH WILL BE JUST
ENOUGH FOR PRECIPITATION TO DEVELOP. UNCERTAINTY STILL REMAIN ON
HOW MUCH MOISTURE WILL BE AVAILABLE BUT MODELS CONTINUE TO BREAK
OUT PRECIPITATION ACROSS THE FORECAST AREA AFTER MIDNIGHT TUESDAY
MORNING. MODEL SOUNDINGS AND CROSS SECTIONS SHOW THE COLUMN WILL
MOISTEN FROM THE TOP DOWN WITH THE NORTHWESTERN SOUTH PLAINS
HAVING THE BEST CHANCE AT REACHING SATURATION. STRONG LIFT
ASSOCIATED WITH THE APPROACHING TROUGH WILL HELP TO COOL THE COLUMN
SO THAT WE WILL SEE A TRANSITION FROM RAIN TO SNOW THROUGH THE
EARLY MORNING HOURS. SUCH STRONG LIFT AND A BIT OF ELEVATED
INSTABILITY AROUND 06Z MAY BE ENOUGH TO RESULT IN SOME HEAVIER
PRECIPITATION ELEMENTS IN A BROAD AREA OF STRATIFORM
PRECIPITATION. PRECIPITATION WILL START OFF AS RAIN AND THEN START
A TRANSITION FROM NORTHWEST TO SOUTHEAST TO A RAIN/SNOW MIX...THEN
ALL SNOW. SNOW LINE WILL PROBABLY MAKE IT TO THE EDGE OF THE
CAPROCK AND AS FAR SOUTH AS A LUBBOCK TO DENVER CITY LINE LEAVING
THE ROLLING PLAINS AND FAR SOUTHERN SOUTH PLAINS AS ALL RAIN.
ACCUMULATIONS ARE EXPECTED TO REMAIN BELOW ONE INCH BUT A FEW
LOCATIONS ACROSS THE NORTHWESTERN SOUTH PLAINS COULD BUMP UP CLOSE
TO AN INCH.
PRECIPITATION WILL COME TO A FAIRLY FAST END BY 12Z TUESDAY MORNING
AS THE TROF AXIS MOVES EAST OF THE AREA AND THE BEST MID-LEVEL
MOISTURE SHIFTS EAST OF THE REGION. BREEZY NORTHERLY WIND WILL BE
IN PLACE THROUGH THE DAY TUESDAY WHICH WILL KEEP HIGH TEMPERATURES
IN THE LOW 40S ON THE CAPROCK TO NEAR 50 ACROSS THE ROLLING
PLAINS. COMBINED WITH THE STRONG NORTH WIND...WIND CHILL READINGS
WILL BE PRETTY COLD WITH SOME MID 20 F READINGS THROUGHOUT THE
DAY. NORTHWEST FLOW ALOFT ON WEDNESDAY WILL RESULT IN A DEEPENING
LEE SURFACE TROF HELPING TO MODERATE TEMPERATURES BACK INTO THE
LOW/MID 50S FOR CHRISTMAS EVE DAY. CHRISTMAS DAY STILL APPEARS TO
BE BREEZY WITH THE POSSIBILITY OF A BROWN CHRISTMAS...MODELS
CONTINUE TO SLOWLY CREEP WIND SPEEDS UP ACROSS THE REGION.
HOWEVER...MODELS NOW HAVE ZONAL FLOW ACROSS THE AREA WHICH DOES
NOT FAVOR WIND SPEEDS AS STRONG AS WAS BELIEVED 2-3 DAYS AGO. LEE
SURFACE TROUGH WILL DEEPEN THROUGH THE DAY WEDNESDAY RESULTING IN
WESTERLY SURFACE WIND 15-25 MPH WITH GUSTS UP TO 35 MPH. THIS WILL
BOOST TEMPERATURES INTO THE MID TO UPPER 60S ACROSS THE REGION
MAKING FOR A WARMER THAN NORMAL CHRISTMAS. HELD OFF MENTIONING ANY
KIND OF BLOWING DUST IN THE GRIDS UNTIL WE GET CLOSER AND HAVE A
BETTER HANDLE ON WHAT THE PEAK WIND SPEEDS WILL BE.
AFTER CHRISTMAS AND HEADING INTO THE HOLIDAY WEEKEND...A COLD
FRONT WILL ARRIVE EARLY FRIDAY MORNING BRINGING TEMPERATURES BACK
DOWN TO NEAR OR JUST BELOW NORMAL FOR FRIDAY AND SATURDAY. THIS
PASSAGE WILL BE DRY AS THE BEST LOW-LEVEL MOISTURE WILL BE WELL
SOUTH OF THE AREA. A BIT OF A WARMUP WILL ENSUE AT THE END OF THE
WEEKEND AS SURFACE FLOW VEERS BACK TO THE SOUTH TO SOUTHWEST
SUNDAY AFTERNOON.
JORDAN
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NIL.
&&
$$
93/14/93
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
434 AM CST SUN DEC 21 2014
.SHORT TERM...
SURFACE TROUGH WAS FOUND PUSHING ACROSS OUR WESTERN COLUMN OF
COUNTIES AT 09Z AHEAD OF MUCH LOWER DEWPOINTS. EAST OF THIS TROUGH
IS WHERE STRATUS HAS BEEN ANCHORED SINCE EARLY LAST NIGHT...
HOWEVER UNLIKE RECENT DAYS WE EXPECT THESE LOW CLOUDS TO QUICKLY
ERODE FROM W-E AS THE SURFACE TROUGH MOTORS EAST IN RESPONSE TO A
S/W TROUGH NOW ENTERING THE WESTERN TX PANHANDLE. FOG-WISE...AREA
CAMERAS AND METARS AT 09Z SHOW THE LOWEST VISBYS OF 1/2 TO 1 MILE
CONFINED TO A RELATIVELY SMALL AREA FROM SEMINOLE TO LUBBOCK TO
LAMESA. HRRR HAS HIGHLIGHTED THIS AREA FOR FOG FOR SEVERAL RUNS...
BUT ITS VISBYS REMAIN TOO PESSIMISTIC COMPARED TO GROUND TRUTH AND
THIS REDUCES CONFIDENCE IN DENSE FOG DEVELOPMENT AND ANY NEED FOR
A HEADLINE. WILL KEEP MENTION OF LOCALLY DENSE FOG IN NOWCASTS...
BUT EVEN THIS WINDOW IS SHRINKING AS THE SURFACE TROUGH CONTINUES
EDGING CLOSER WITH IMPROVING VISBYS.
SUBSIDENCE BEHIND THE AFOREMENTIONED S/W TROUGH WILL HELP RID ANY
LINGERING STRATUS FROM THE ROLLING PLAINS BY MIDDAY WHILE ALSO
SERVING TO BOOST 1000-500MB THICKNESSES TO NEARLY 561 DAM. OPTED
FOR THE BCCONSALL WITH HIGH TEMPS TODAY AS REMAINING GUIDANCE
LOOKED TOO COOL FOR THIS PATTERN OF DEEP WLY FLOW AND DRY
DOWNSLOPE WINDS. THESE MILD THICKNESS VALUES FALL VERY LITTLE
TONIGHT THANKS TO AN IMPRESSIVE LL THERMAL RIDGE MIGRATING SOUTH
AHEAD OF MONDAY/S COLD FRONT...SO MIN TEMPS WERE BOOSTED 2 TO 5
DEGREES. THESE SEEMINGLY MILD LOW TEMPS MAY STILL PROVE TOO COOL
GIVEN WEST WINDS OVERNIGHT OF 10 TO 15 MPH.
&&
.LONG TERM...
COMPLICATED LONG TERM FORECAST FOR NEXT WEEK AS A SERIES OF STORM
SYSTEMS WILL IMPACT THE AREA. FIRST ONE WILL BE MONDAY NIGHT INTO
TUESDAY MORNING. A WEAK COLD FRONT WILL PUSH INTO THE AREA DURING
THE DAY MONDAY WITH SOME DIFFERENCES ON HOW FAR SOUTH IT WILL MAKE
IT INTO THE FORECAST AREA. FRONTAL LOCATION IS WAFFLING NORTHWEST
TO SOUTHEAST ACROSS THE FORECAST AREA DEPENDING ON THE MODEL AND
THE TIME OF THE RUN. HOWEVER...GENERAL CONSENSUS IS FOR THE FRONT
TO MAKE IT INTO ALL BUT THE FAR SOUTHWESTERN COUNTIES BY MONDAY
AFTERNOON. NORTH WIND WILL NOT BE PARTICULARLY STRONG BEHIND THE
FRONT BUT ENOUGH THIS WILL SET UP ABOUT A 10-14 DEGREE TEMPERATURE
GRADIENT FROM NORTH TO SOUTH ACROSS THE REGION. ALSO TAKING PLACE
THROUGH THE DAY...A CLOSED LOW ALOFT WILL MOVE ACROSS THE NORTHERN
PLAINS TOWARDS THE GREAT LAKES. A STRONG 140-160KT JET WILL MOVE
SOUTHWARD ON THE WESTERN EDGE OF THE LOW HELPING TO DEEPEN THE
TROUGH ASSOCIATED WITH THE CLOSED LOW AS THE TROF AXIS IS JUST
WEST OF THE REGION. A POCKET OF MID-LEVEL MOISTURE WILL ARRIVE AT
THE SAME TIME THE TROF IS MOVING OVERHEAD WHICH WILL BE JUST
ENOUGH FOR PRECIPITATION TO DEVELOP. UNCERTAINTY STILL REMAIN ON
HOW MUCH MOISTURE WILL BE AVAILABLE BUT MODELS CONTINUE TO BREAK
OUT PRECIPITATION ACROSS THE FORECAST AREA AFTER MIDNIGHT TUESDAY
MORNING. MODEL SOUNDINGS AND CROSS SECTIONS SHOW THE COLUMN WILL
MOISTEN FROM THE TOP DOWN WITH THE NORTHWESTERN SOUTH PLAINS
HAVING THE BEST CHANCE AT REACHING SATURATION. STRONG LIFT
ASSOCIATED WITH THE APPROACHING TROUGH WILL HELP TO COOL THE COLUMN
SO THAT WE WILL SEE A TRANSITION FROM RAIN TO SNOW THROUGH THE
EARLY MORNING HOURS. SUCH STRONG LIFT AND A BIT OF ELEVATED
INSTABILITY AROUND 06Z MAY BE ENOUGH TO RESULT IN SOME HEAVIER
PRECIPITATION ELEMENTS IN A BROAD AREA OF STRATIFORM
PRECIPITATION. PRECIPITATION WILL START OFF AS RAIN AND THEN START
A TRANSITION FROM NORTHWEST TO SOUTHEAST TO A RAIN/SNOW MIX...THEN
ALL SNOW. SNOW LINE WILL PROBABLY MAKE IT TO THE EDGE OF THE
CAPROCK AND AS FAR SOUTH AS A LUBBOCK TO DENVER CITY LINE LEAVING
THE ROLLING PLAINS AND FAR SOUTHERN SOUTH PLAINS AS ALL RAIN.
ACCUMULATIONS ARE EXPECTED TO REMAIN BELOW ONE INCH BUT A FEW
LOCATIONS ACROSS THE NORTHWESTERN SOUTH PLAINS COULD BUMP UP CLOSE
TO AN INCH.
PRECIPITATION WILL COME TO A FAIRLY FAST END BY 12Z TUESDAY MORNING
AS THE TROF AXIS MOVES EAST OF THE AREA AND THE BEST MID-LEVEL
MOISTURE SHIFTS EAST OF THE REGION. BREEZY NORTHERLY WIND WILL BE
IN PLACE THROUGH THE DAY TUESDAY WHICH WILL KEEP HIGH TEMPERATURES
IN THE LOW 40S ON THE CAPROCK TO NEAR 50 ACROSS THE ROLLING
PLAINS. COMBINED WITH THE STRONG NORTH WIND...WIND CHILL READINGS
WILL BE PRETTY COLD WITH SOME MID 20 F READINGS THROUGHOUT THE
DAY. NORTHWEST FLOW ALOFT ON WEDNESDAY WILL RESULT IN A DEEPENING
LEE SURFACE TROF HELPING TO MODERATE TEMPERATURES BACK INTO THE
LOW/MID 50S FOR CHRISTMAS EVE DAY. CHRISTMAS DAY STILL APPEARS TO
BE BREEZY WITH THE POSSIBILITY OF A BROWN CHRISTMAS...MODELS
CONTINUE TO SLOWLY CREEP WIND SPEEDS UP ACROSS THE REGION.
HOWEVER...MODELS NOW HAVE ZONAL FLOW ACROSS THE AREA WHICH DOES
NOT FAVOR WIND SPEEDS AS STRONG AS WAS BELIEVED 2-3 DAYS AGO. LEE
SURFACE TROUGH WILL DEEPEN THROUGH THE DAY WEDNESDAY RESULTING IN
WESTERLY SURFACE WIND 15-25 MPH WITH GUSTS UP TO 35 MPH. THIS WILL
BOOST TEMPERATURES INTO THE MID TO UPPER 60S ACROSS THE REGION
MAKING FOR A WARMER THAN NORMAL CHRISTMAS. HELD OFF MENTIONING ANY
KIND OF BLOWING DUST IN THE GRIDS UNTIL WE GET CLOSER AND HAVE A
BETTER HANDLE ON WHAT THE PEAK WIND SPEEDS WILL BE.
AFTER CHRISTMAS AND HEADING INTO THE HOLIDAY WEEKEND...A COLD
FRONT WILL ARRIVE EARLY FRIDAY MORNING BRINGING TEMPERATURES BACK
DOWN TO NEAR OR JUST BELOW NORMAL FOR FRIDAY AND SATURDAY. THIS
PASSAGE WILL BE DRY AS THE BEST LOW-LEVEL MOISTURE WILL BE WELL
SOUTH OF THE AREA. A BIT OF A WARMUP WILL ENSUE AT THE END OF THE
WEEKEND AS SURFACE FLOW VEERS BACK TO THE SOUTH TO SOUTHWEST
SUNDAY AFTERNOON.
JORDAN
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 59 34 56 25 41 / 0 0 0 50 0
TULIA 58 35 56 28 42 / 0 0 0 50 0
PLAINVIEW 59 36 58 29 42 / 0 0 0 50 10
LEVELLAND 63 37 63 30 44 / 0 0 0 50 10
LUBBOCK 63 38 61 31 44 / 0 0 0 50 10
DENVER CITY 62 39 68 32 46 / 0 0 0 50 10
BROWNFIELD 62 38 67 32 45 / 0 0 0 50 10
CHILDRESS 61 37 59 35 48 / 0 0 0 30 10
SPUR 63 39 63 36 48 / 0 0 0 40 10
ASPERMONT 64 42 67 38 51 / 0 0 0 40 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93/14
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
913 PM CST MON DEC 22 2014
.UPDATE...
ISSUED AT 913 PM CST MON DEC 22 2014
CONFIDENCE IS INCREASING THAT SOME HEAVIER SNOWS WILL BE MAKING IT
INTO CLARK COUNTY TONIGHT INTO TOMORROW AFTERNOON...SO HAVE
DECIDED TO ADD THEN INTO THE ADVISORY. 23.01Z RAP SOUNDINGS FROM
CLARK COUNTY SHOW THE THERMAL PROFILE STAYING BELOW FREEZING WITH
THE EXCEPTION OF THE NEAR SURFACE LAYER WHICH ONLY GETS TO 33F OR
SO. AT LEAST FOR THIS EVENING 34F APPEARS TO BE THE CHANGEOVER
LEVEL FROM RAIN TO SNOW...SO WILL USE THAT INTO TONIGHT INTO
TOMORROW. OUTSIDE OF THE ADJUSTMENT TO ADD CLARK TO THE
ADVISORY...WILL BE WAITING ON THE 23.00Z DATA TO COME IN BEFORE
MAKING ANY CHANGES TO THE PREVIOUS FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 245 PM CST MON DEC 22 2014
CHALLENGES CONTINUE WITH THE WINTER STORM THIS EVENING THROUGH
TUESDAY...NAMELY PRECIPITATION TYPE AND SNOW AMOUNTS. 22.12Z MODEL
SUITE MASS FIELDS IN GOOD OVERALL AGREEMENT THROUGH THE EVENT.
HOWEVER...MINOR DIFFERENCES IN THE THERMAL PROFILES...COMPOUNDED
BY THE FACT THAT SOUNDINGS WOBBLE ABOUT THE ZERO DEGREE ISOTHERM
MAKE PRECIPITATION TYPE PARTICULARLY DIFFICULT. ALL SAID...THERE
HAS STILL BEEN A SOUTHERN TREND IN THE TRACK OF THE SURFACE LOW AS
IT BRIEFLY DIPS INTO NORTHERN MO THIS EVENING BEFORE EJECTING
NORTHEASTWARD ACROSS SOUTHERN WI ON TUESDAY. THIS ALLOWS THE
PRIMARY DEFORMATION AXIS TO SET-UP ACROSS THE NORTHWEST THIRD OF
THE FORECAST AREA AND ENHANCES THE CHANCE FOR ACCUMULATING
SNOWFALL PRIMARILY ON TUESDAY.
FOR THIS EVENING...FIRST WAVE OF PRECIPITATION WILL LIFT ACROSS
THE FORECAST AREA. THERMAL PROFILES ARE WARM ENOUGH FOR MOSTLY
RAIN...EXCEPT ACROSS TAYLOR/CLARK COUNTIES WHERE SOME ACCUMULATING
SNOW (LESS THAN AN INCH) IS POSSIBLE. TEMPERATURES WILL CHANGE
VERY LITTLE AND REMAIN IN THE MID TO UPPER 30S.
FOR TONIGHT...LOW-MID LEVEL WARM FRONT WILL SURGE NORTHWARD AS
SURFACE LOW MOVES INTO NORTHEAST IA. A SECONDARY WAVE OF
PRECIPITATION WILL SWEEP ACROSS THE FORECAST AREA FROM SOUTH TO
NORTH ALONG AXIS OF STRONG WARM AIR ADVECTION AND ISENTROPIC LIFT.
IN GENERAL...EXPECT A NARROW CORRIDOR OF A RAIN SNOW MIX NEAR THE
TRACK OF THE SURFACE LOW WITH SNOW TO THE NORTHWEST AND RAIN TO
THE SOUTHEAST. MODELS ARE HINTING AT A 925 TO 850 HPA WARM TONGUE
TO WRAP AROUND THE LOW BY TUESDAY MORNING...BUT ITS IMPACT ON
PRECIPITATION TYPE SHOULD BE FELT MAINLY FOR AREAS THAT WILL
ALREADY BE SEEING RAIN.
ACCUMULATING SNOW IS MAINLY A CONCERN ON TUESDAY WEST OF A LINE
FROM OELWEIN TO LA CROSSE TO WAUSAU. EXPECT RAIN OR A RAIN/SNOW MIX
FARTHER SOUTH AND EAST. WARM AIR THIS EVENING AND A SLOW
TRANSITION TO A COLDER AIR MASS MAY INITIALLY LIMIT SNOWFALL...
BUT MODELS SHOW ALL BUT THE NEAR SURFACE LAYER DROPPING BELOW
FREEZING BY 23.12Z. EXPECT STRONG LIFT FROM 5 TO 8 UBAR/SECOND
ALONG THE -15 C ISOTHERM WITHIN DEFORMATION SNOW AXIS TO GENERATE
SNOWFALL RATES HIGH ENOUGH TO OVERCOME WARM SURFACE TEMPERATURES
AND ACCUMULATE. NEW FORECAST CALLS FOR 1-3 INCHES OF HEAVY WET
SNOW ACROSS PORTIONS OF NORTHEAST IA/SOUTHEAST MN/WESTERN WI WITH
THE HIGHEST AMOUNTS ACROSS ELEVATED TERRAIN. THIS MATCHES FAIRLY
WELL WITH LATEST GFS/NAM COBB OUTPUT AND SREF PLUMES. ACCUMULATING
SNOWFALL WILL BE BEST REALIZED ACROSS GRASSY SURFACES...BUT COULD
STILL SEE SLUSH ACCUMULATIONS ON UNTREATED ROADWAYS MAKING TRAVEL
DIFFICULT...ESPECIALLY DURING THE TUESDAY MORNING COMMUTE. WILL
KEEP CURRENT WINTER WEATHER ADVISORY FOR TAYLOR COUNTY AND MONITOR
ALL OTHER AREAS FOR POSSIBLE EXPANSION. SEE SPS FOR ADDITIONAL
INFORMATION.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 PM CST MON DEC 22 2014
PRECIPITATION WILL DISSIPATE TUESDAY NIGHT WITH ONLY SOME
LINGERING LIGHT SNOW POSSIBLE ON CHRISTMAS EVE DAY. TEMPERATURES
WILL REMAIN IN THE MID 30S. CHRISTMAS DAY WILL BE DRY WITH LITTLE
CHANGE IN TEMPERATURE AS A BROAD SURFACE RIDGE SLIDES ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY.
SNOW CHANCES INCREASE THURSDAY NIGHT THROUGH FRIDAY AS THE NEXT
TROUGH CARVES ITS WAY ACROSS THE WESTERN CONUS. SURFACE LOW TRACK
IS SIMILAR BETWEEN THE 22.12Z GFS/ECMWF/GEM...BUT PRECIPITATION
PLACEMENT DIFFERS BETWEEN THE DRIER ECMWF AND WETTER GFS/GEM. FOR
NOW...WILL FOLLOW SUPERBLEND GUIDANCE AND BROAD BRUSH CHANCE POPS
ACROSS THE FORECAST AREA.
AFTER A COLD FRONT SWEEPS ACROSS THE REGION FRIDAY NIGHT...THE
UPCOMING WEEKEND LOOKS DRY BUT COLDER WITH DAILY HIGH TEMPERATURES
IN THE 20S AND NIGHTTIME LOWS MAINLY IN THE TEENS. THERE IS A
SLIGHT CHANCE FOR SNOW SUNDAY NIGHT INTO MONDAY...BUT GIVEN VAST
MODEL DIFFERENCES...WILL KEEP 20 POPS AT THIS TIME.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 538 PM CST MON DEC 22 2014
ONE BAND OF -RA OR -RA/-SN WAS LIFTING NORTH ACROSS THE TAF SITES
LATE THIS AFTERNOON/EARLY THIS EVENING. THIS BAND TO LIFT NORTH OF
THE TAF SITES BY 02Z. BULK OF VSBY RESTRICTION DURING THE MID
EVENING TO EARLY OVERNIGHT HOURS DUE TO BR AND SOME -DZ AS MOIST AIR
IS ADVECTED OVER THE COLD GROUND. CIGS TO REMAIN MVFR/IFR TONIGHT. A
SECOND BAND OF -RA/-SN WILL DEVELOP OVER MO/IA THIS EVENING...THEN
LIFT NORTH INTO/ACROSS THE TAF SITES MAINLY 09-18Z TUE. AS THE
AIRMASS COOLS LATE TONIGHT...PRECIP IN THIS BAND EXPECTED TO SWITCH
TO ALL SNOW. PRESENT TIMING WOULD PUT THE SWITCH TO ALL SNOW AROUND
06Z AT KRST...WITH THE HEAVIER SNOW FALLING BETWEEN 09-18Z AS THE
BAND PIVOTS ACROSS THE AREA. A LITTLE TRICKER IN THE MS RIVER VALLEY
AT KLSE. PRECIP NOT EXPECTED TO SWITCH TO SNOW AT KLSE ON THE MS
VALLEY FLOOR UNTIL NEAR/AFTER 12Z WHEN THE HEAVIER PORTION OF THE
BAND WOULD MOVE IN. WITH SOME DIURNAL WARMING...-SN TO MIX WITH -RA
FOR THE AFTERNOON OR BECOME LIGHTER AS AS THE MAIN PRECIP BAND LIFTS
NORTH OF THE TAF SITES. IFR/MVFR CIGS/VSBYS TO PERSIST THRU TUE. 2
TO 3 INCHES OF SNOW IMPACTING AIRPORT OPS EXPECTED AT KRST LATE
TONIGHT/TUE MORNING...WITH PERHAPS A SLUSHY INCH OR SO AT KLSE TUE
MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST TUESDAY FOR WIZ017-029.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...ROGERS
LONG TERM...ROGERS
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
303 PM CST SUN DEC 21 2014
.REST OF THIS AFTERNOON AND TONIGHT - CONFIDENCE...MEDIUM
LEAD WAVE COMBINED WITH WAA GENERATING LIGHT PRECIP RETURNS ACROSS
WRN CWA. HOWEVER 88-D TRENDS SHOW COVERAGE DECREASING RAPIDLY WITH THIS.
SPOTTY LIGHT RAIN OR LIGHT SNOW WITH THIS BAND. MOIST FLOW CONTINUES
AHEAD OF ADVANCING LOW PRESSURE TROUGH IN THE PLAINS. SURFACE TEMPS
NOT EXPECTED TO DROP MUCH DUE TO SOUTHERLY WINDS AND CLOUD COVER. MID
LEVEL SHORTWAVE EXPECTED TO AMPLIFY AS IT DRAWS CLOSER. WEAKER SHORTWAVE
TO BRUSH SRN WI AFTER 6Z. WILL KEEP POPS CONFINED TO NW CWA CLOSER TO
850 LLJ AXIS AND AREA OF MODEL QPF. WITH MID LEVELS SHOWING A DRY LOOK
ON BUFKIT SOUNDINGS AND ANTICIPATED TEMPS REMAINING ABV ZERO NOT
EXPECTING ANY FREEZING RAIN/DRIZZLE.
.MONDAY - CONFIDENCE...MEDIUM
NEARLY STACKED LOW MOVERS INTO WESTERN IOWA. SHORTWAVE ENERGY WRAPPING
AROUND THIS UPPER LOW SHIFTS INTO SRN WI AND COINCIDES WITH INCREASING
850 MILLIBAR WIND MAX DURING THE AFTERNOON HOURS. MILD AIRMASS WITH HIGHS
IN THE U30S/L40S EXPECTED. NAM SOUNDING IN NW CWA LOOK A SMIDGE COLD
IN THE LOW LEVELS. PREFER THE BETTER HANDLING OF LOW LEVEL TEMP PROFILE
ON THE GFS SOUNDING. BUT PRECIP TYPE STILL QUESTIONABLE INTO THE AFTERNOON
ACROSS THE NW CWA. AREA SOUNDINGS SHOWING SN POTENTIAL WITH SATURATION IN THE
DENDRIDIC GROWTH ZONE. HOWEVER LOW LEVELS WILL DETERMINE EVENTUAL PRECIP
TYPE. SO WILL STILL KEEP MIXED PRECIP INTO THE AFTERNOON THERE WITH VRY LGT
ACCUMS. MUCH OF CWA EXPECTED TO BE RAIN IN THE AFTN THOUGH THE NW IS STILL
VULNERABLE WITH LOWEST 850 TEMPS AND COLDEST 1000-500 MILLIBAR THICKNESSES.
.MONDAY NIGHT AND TUESDAY...FORECAST CONFIDENCE IS HIGH.
FAIRLY STRONG DYNAMICS ARRIVE MONDAY NIGHT AS THE MAIN CLOSED MID
LEVEL LOW SPINS OVER IOWA INTO SOUTHERN MN...EJECTING DECENT SHORT
WAVE ENERGY NORTHEAST INTO WISCONSIN. THE ASSOCIATED SURFACE LOW
WILL TRACK FROM NORTHWEST IOWA TO NORTH CENTRAL WISCONSIN BETWEEN
6 PM MONDAY THROUGH MID-DAY ON TUESDAY. DECENT WARM AIR ADVECTION
AHEAD OF THE LOW...RESULTING IN STRONG Q-VECTOR CONVERGENCE WHEN
COUPLED WITH THE MID LEVEL SHORT WAVE...SUPPORTS VERY HIGH POPS
INTO THE EVENING. TEMP PROFILES SUPPORT ALL RAIN WITH THE
POSSIBILITY OF A RAIN/SNOW MIX NORTHWEST OF MADISON.
WE SHOULD GET DRY SLOTTED LATER MONDAY NIGHT THROUGH TUESDAY WITH
LOW POPS MOVING IN. LIKELY JUST ANOTHER CLOUDY DAY WITH A SMALL
CHANCE OF RAIN OR SOME DRIZZLE AS THIS FIRST LOW MOVES OFF TO THE
NORTHEAST. TEMPS WILL BE MILD AS WE REMAIN ON THE WARM SIDE OF
THE LOW/TROF.
.TUESDAY NIGHT THROUGH WEDNESDAY...FORECAST CONFIDENCE
INCREASING.
IF YOU/VE BEEN FOLLOWING THE DISCUSSIONS...YOU KNOW THERE HAS BEEN
AN INCREDIBLE AMOUNT OF MODEL VARIABILITY IN THE HANDLING OF THE
SECONDARY LOW PRESSURE DEVELOPMENT COMING OUT OF THE LOWER
MISSISSIPPI VALLEY FOR THIS PERIOD. THE NEW 12Z RUNS ARE MUCH
TIGHTER AND THE LOWER SPREADS IN POSSIBLE SOLUTIONS PROVIDES
HIGHER CONFIDENCE. THE CONSENSUS LOW TRACK IS FROM THE OHIO VALLEY
NEAR LOUISVILLE TO SOUTHEAST LOWER MICHIGAN...THEN NORTHEAST FROM
THERE. THE SOUTHEAST WISCONSIN FORECAST AREA...INCLUDING THE
MILWAUKEE METRO AREA COULD GET INTO THE FAR WESTERN PRECIP SHIELD
AND GENERATE SOME LIGHT SNOW. BUT TEMPS WOULD PROBABLY STILL BE
WARM ENOUGH TO MELT MOST OF IT.
THE GFS/ECMWF/NAM/GEM KEEP THE HIGHEST IMPACT WEATHER WELL EAST
OF US. OF MINOR CONCERN IS A 12Z SUN PARALLEL HIGH RESOLUTION RUN
OF THE GFS THAT SHOWS A MAJOR LOW MOVING FROM ST. LOUIS TO
MILWAUKEE DURING THIS TIME. IT HAS BEEN ASSESSED AS A SIGNIFICANT
OUTLIER...NOT CLOSE TO ANY OTHER ENSEMBLE RUNS...AND IS BEING
DISCARDED. I MENTION IT AS THIS SOLUTION MAY MAKE IT/S WAY OUT
INTO THE SOCIAL MEDIA WORLD AND RAISE QUESTIONS. AND THE
CAVEAT...WE CAN/T LET OUR GUARD DOWN. THE TRACKS OF THESE LOWS CAN
CHANGE...SO REMAIN UP TO DATE ON THE LATEST FORECAST THROUGH
CHRISTMAS EVE.
.CHRISTMAS DAY...FORECAST CONFIDENCE IS HIGH.
FOR ALL THOSE PLANNING TO TRAVEL ON THE HOLIDAY...IT LOOKS LIKE A
DECENT DAY WITH DRY WEATHER AS HIGH PRESSURE BRIEFLY BUILDS IN.
TEMPS WILL BE IN THE LOWER TO MID 30S.
.FRIDAY...FORECAST CONFIDENCE IS MEDIUM.
LATE THURSDAY NIGHT AND FRIDAY...A FAST MOVING SHORT WAVE ARRIVES
IN THE ZONAL FLOW AND COULD BRING AROUND AN INCH OF SNOW. THE GFS
IS MUCH FARTHER NORTH WITH THE SFC LOW TRACK COMPARED TO THE
ECMWF AND THIS HAS BEEN THE CASE FOR THE LAST FEW RUNS. WPC IS
FAVORING THE ECMWF WHICH WILL SUPPORT A COLDER SOLUTION...WITH
THAT INCH OF SNOW POSSIBLE.
.SATURDAY AND SUNDAY...FORECAST CONFIDENCE IS MEDIUM.
LOOKS LIKE HIGH PRESSURE RETURNS FOR NEXT WEEKEND. IT LOOKS DRY
WITH TEMPS RUNNING BELOW NORMAL...GENERALLY HIGHS IN THE LOWER TO
MID 20S.
&&
.AVIATION/00Z TAFS/...COMBO OF SHORTWAVE TROUGH MOVING EAST FROM WRN
MN AND WRN IA ALONG WITH SUSTAINED WAA...RESULTING IN MOST
WIDESPREAD PRECIP ACRS EC MN INTO NW WI. BAND OF MORE SCATTERED
PRECIP EXTENDS SOUTHWARD THROUGH SC WI. THIS WILL CONTINUE TO
TRANSLATE EWD THIS AFTN/ERLY EVE MOVING THROUGH THE REST OF SRN WI.
SFC TEMPS ABV FREEZING. RAP BUFKIT SOUNDINGS SHOW THE LOW LEVEL
SATURATION WITH DRY LAYER ABV AND HINTS OF MID LEVEL SATURATION
WITHIN DENDRIDIC GROWTH ZONE...SO CANNOT RULE OUT SOME SNOW...THOUGH
SEEDER FEEDER DRY DEPTH IS FAIRLY LARGE. IFR CIGS AND VSBYS WILL
PREVAIL WITH THE NAM MOS AND CONSSHORT HAVING THE BEST HANDLE ON
CIG/VSBY TRENDS. OVERALL MODELS KEEP MOST OF PRECIP THIS PERIOD
ACROSS WRN AND NRN WI WITH LESS IN THE SE. WITH LOW PRESSURE AND
MORE ORGANIZED SHORTWAVE APPROACHING MONDAY AFTERNOON/EVENING EXPECT
MORE WIDESPREAD RAINFALL MOVING INTO SRN WI. ANY MIXY POTENTIAL
LOOKS TO BE NORTH OR NORTHWEST OF TAF SITES.
&&
.MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT FROM PORT WASHINGTON
AND NWD AND STARTS AT 10 PM SOUTH OF PORT WASHINGTON. AS LOW
PRESSURE APPROACHES FROM THE NORTHERN PLAINS...BREEZY SOUTH TO
SOUTHEAST WINDS WILL CONTINUE TO RAMP UP INTO MONDAY NIGHT. THE
SOUTHERLY FETCH WILL GENERATE HIGH WAVES DURING THIS PERIOD. THE
WINDS AND WAVES WILL SUBSIDE ON TUESDAY AS THE WEAKENING LOW
PRESSURE AREA MOVES ACROSS THE REGION. THE SMALL CRAFT ADVISORY WILL
EXPIRE EARLY TUE AM.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 3 AM CST TUESDAY
FOR LMZ644>646.
SMALL CRAFT ADVISORY UNTIL 3 AM CST TUESDAY FOR LMZ643.
&&
$$
TONIGHT/MONDAY AND AVIATION/MARINE...COLLAR
MONDAY NIGHT THROUGH SUNDAY...DAVIS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1104 AM CST SUN DEC 21 2014
.AVIATION/18Z TAFS/...COMBO OF SHORTWAVE TROUGH MOVING EAST FROM
WRN MN AND WRN IA ALONG WITH SUSTAINED WAA...RESULTING IN MOST
WIDESPREAD PRECIP ACRS EC MN INTO NW WI. BAND OF MORE SCATTERED
PRECIP EXTENDS SOUTHWARD THROUGH FAR WRN WI. THIS WILL CONTINUE
TO TRANSLATE EWD THIS AFTN MOVING THROUGH SRN WI. SFC TEMPS RISING
ABV FREEZING. RAP BUFKIT SOUNDINGS SHOW THE LOW LEVEL SATURATION
WITH DRY LAYER ABV AND HINTS OF MID LEVEL SATURATION WITHIN
DENDRIDIC GROWTH ZONE...SO CANNOT RULE OUT SOME SNOW...THOUGH
SEEDER FEEDER DRY DEPTH IS FAIRLY LARGE. IFR CIGS AND VSBYS WILL
PREVAIL WITH THE NAM MOS AND CONSSHORT HAVING THE BEST HANDLE ON
CIG/VSBY TRENDS. OVERALL MODELS KEEP MOST OF PRECIP THIS PERIOD
ACROSS WRN AND NRN WI WITH LESS IN THE SE. WITH LOW PRESSURE AND
MORE ORGANIZED SHORTWAVE APPROACHING MONDAY AFTERNOON/EVENING
EXPECT MORE WIDESPREAD RAINFALL MOVING INTO SRN WI. ANY MIXY
POTENTIAL LOOKS TO BE NORTH OR NORTHWEST OF TAF SITES.
PC
&&
.PREV DISCUSSION... /ISSUED 402 AM CST SUN DEC 21 2014/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM.
AREAS OF VERY LIGHT FREEZING DRIZZLE AND A FEW SNOWFLAKES ARE
OVERSPREADING MUCH OF THE CWA FROM THE SW VIA LOW LEVEL WARM...MOIST
ADVECTION. SFC TEMPS TO WARM ABOVE FREEZING BY 16Z. DO NOT BELIEVE
THERE WILL BE ENOUGH OF AN IMPACT ON ROADWAYS FOR A FREEZING RAIN
ADVISORY AT THIS TIME. THE RESIDUAL CHEMICALS AND SALT ON ROADWAYS
FROM THE PAST SEVERAL DAYS MAY BE ENOUGH TO KEEP THE ROADS IN OKAY
CONDITION.
AS A WEAK SHORTWAVE TROUGH APPROACHES FROM THE PLAINS
TODAY AND PASSES TNT...THE 850 MB BAROCLINIC ZONE WILL SHIFT NEWD
ACROSS THE CWA THROUGHOUT THE DAY. FCST SOUNDINGS CONTINUE TO SHOW A
MID LEVEL DRY LAYER BUT STILL EXPECT THE LIFT TO RESULT IN SEEDER
FEEDER MECHANISM OR OUTRIGHT SATURATION IN SOME AREAS. THUS HAVE
CHANCE POPS FOR RAIN AND SNOW FROM LATE THIS MORNING THROUGH THE
AFTERNOON. THE CHANCES OF RAIN...SNOW...AND POSSIBLY FREEZING
DRIZZLE CONTINUE TNT WITH THE PASSAGE OF THE WEAK SHORTWAVE TROUGH
AND CONTINUED MOISTURE IN THE LOW LEVELS.
MONDAY-FORECAST CONFIDENCE HIGH
MODELS IN GOOD AGREEMENT IN STACKED AND FILLING LOW MOVING FROM
SOUTHEAST DAKOTA INTO IOWA. THERE HAS BEEN A TREND FOR THERMAL
PROFILES AROUND 850MB TO BE COOLER WITH THIS SYSTEM...WITH 850 MB
TEMPS HOVERING AROUND 0C. HOWEVER...JUST ENOUGH OF A LAPSE RATE IN
BOUNDARY LAYER WITH STALE COLD AIR AT SURFACE TO PERMIT TEMPERATURES
TO RISE WELL INTO THE 30S. CERTAINLY COULD BE MIX OF RAIN AND WET
SNOW...BUT IMPACTS SHOULD BE MINIMAL WITH BULK OF PRECIPITATION
FALLING AS RAIN.
LOOKS LIKE AFTERNOON AND EVENING RUSH HOUR WILL BE WETTEST PERIOD.
LONG TERM...
TUESDAY AND WEDNESDAY-FORECAST CONFIDENCE LOW
NOT SURE HOW TO WORD THIS...BUT IT HAS BEEN A LONG TIME SINCE I HAVE
SEEN THIS MUCH UNCERTAINTY IN A DAY 3 FORECAST. OPERATIONAL GFS AND
SREF HAVE TRENDED SLOWER AND SOUTH TOWARD LOWER MISSISSIPPI RIVER
VALLEY WITH 2ND LOW PRESSURE WAVE...WHILE ECMWF AND PARALLEL GFS
FOCUS ON MORE NORTHERN SOLUTION NEAR THE GREAT LAKES.
AT FIRST GLANCE THE GEFS AND SREF SOLUTIONS SHOW POTENTIAL FOR A
DREADED GULF LOW TRACK WITH HEAVY WET SNOW POTENTIAL.
HOWEVER...WITH TREND OF OTHER RELIABLE MODELS LIKE ECMWF TOWARD
ABSENCE OF DEEP LOW OVER GREAT LAKES...SEE POTENTIAL FOR VERY LITTLE
PRECIPITATION OR SNOW BEING GREATER OVER SOUTHERN WISCONSIN THAN
POTENTIAL FOR SIGNIFICANT STORM.
RIGHT NOW A CONSERVATIVE CONSENSUS FORECAST IS THE ONLY VIABLE
OPTION I SEE. IT LOOKS LIKE GRADUAL COOLING OF THE COLUMN WITH
CHANCE OF RAIN GOING TO SNOW WITH LARGE RANGE OF POSSIBLE
PRECIPITATION AMOUNTS...BUT LEANING TOWARD DRIER SOLUTIONS.
THURSDAY THROUGH SATURDAY-FORECAST CONFIDENCE MEDIUM
GFS AND ECMWF ARE IN BETTER AGREEMENT ON FAST MOVING LOW COMING OUT
OF KANSAS AHEAD OF A POLAR SURGE AND THEN HEADING FOR THE GREAT
LAKES. A FRONTOGENETIC SNOW BAND IS SHOWN TO PUSH FROM NEBRASKA TO
IOWA AND WISCONSIN THURSDAY INTO EARLY FRIDAY.
THIS BAND WOULD BE RATHER NARROW...SO MIGHT ONLY AFFECT 2-3 COUNTY
WIDE AREA AND COULD EASILY MISS MOST AREAS. BEST GUESS RIGHT NOW IS
LIGHT AMOUNTS ESPECIALLY IN NORTHERN HALF OF AREA.
AVIATION/12Z TAFS/...CIGS WILL RANGE FROM JUST A FEW HUNDRED FEET
OR LESS OVER SOUTH CENTRAL WI TO A 1000 FEET IN THE EAST TODAY AS
AREAS OF FREEZING DRIZZLE...RAIN...SNOW MOVE ACROSS THE AREA. SFC
TEMPS TO WARM ABOVE FREEZING BY 10 AM...ENDING THE ICING
THREAT...BUT A LIGHT COATING OF ICE ON SURFACES WILL OCCUR
BEFOREHAND. THE CIGS WILL LIFT TO 1-3 KFT FOR TNT. VSBYS OF 3-5SM
WILL PREVAIL WEST OF THE MILWAUKEE METRO AREA FOR MOST OF SUN AND
SUN NT. RAIN...SNOW...AND PATCHY FREEZING DRIZZLE WILL REMAIN IN THE
FORECAST FOR TNT.
MARINE...A SMALL CRAFT ADVISORY GOES INTO EFFECT LATER THIS
AFTERNOON FROM PORT WASHINGTON AND NWD AND STARTS AT 10 PM SOUTH OF
PORT WASHINGTON. AS LOW PRESSURE APPROACHES FROM THE NORTHERN
PLAINS...BREEZY SOUTH TO SOUTHEAST WINDS WILL DEVELOP LATER TODAY
INTO MONDAY NIGHT. THE SOUTHERLY FETCH WILL GENERATE HIGH WAVES
DURING THIS PERIOD. THE WINDS AND WAVES WILL SUBSIDE ON TUESDAY AS
THE WEAKENING LOW PRESSURE AREA MOVES ACROSS THE REGION. THE SMALL
CRAFT ADVISORY WILL EXPIRE EARLY TUE AM.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 3 AM CST TUESDAY
FOR LMZ644>646.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM CST
TUESDAY FOR LMZ643.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...GEHRING
MONDAY THROUGH SATURDAY...CRAVEN
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
432 AM EST TUE DEC 23 2014
...WIDESPREAD HEAVY RAINFALL AND WAVES OF STRONG TO SEVERE STORMS
EXPECTED THROUGH WED NIGHT...
.SHORT TERM...TODAY THROUGH WED NIGHT...
THIS MORNING...WARM FRONT WAS DRIFTING SLOWLY NORTHWARD OVERNIGHT BUT
HAS BECOME NEARLY STATIONARY EARLY THIS MORNING ALONG THE INTERSTATE
10 CORRIDOR. CLUSTERS OF RAINFALL WITH ISOLATED DISCRETE TSTORMS FIRED
OVERNIGHT ALONG AND SOUTH OF THE FRONT. A FEW STRONG STORMS PRODUCED
HAIL FROM 0.25-1" GIVEN COOLER 500 MB TEMPS NEAR -12 DEG C AND GOOD
DIRECTIONAL SHEAR WITHIN HAIL GROWTH ZONE. THE RAPID REFRESH INTIALIZED
BEST EARLY THIS MORNING WITH PRECIP BAND AND THE POSITION OF THE LINGERING
WARM FRONT THUS LEANED TOWARD THE HRRR SOLUTION FOR THE NEAR-TERM FORECAST
WHICH SHUNTS THE BAND OF EARLY MORNING RAINFALL SLOWLY NORTHWARD OVER
SE GA WITH PRECIP DECREASING ACROSS ATLANTIC COASTAL LOCATIONS. THE
FOCUS OF MORE SCATTERED TO WIDESPREAD RAINFALL AND ISOLATED TSTORMS
THEN SHIFTS OVER THE FL PANHANDLE WHERE LOW LEVEL INSTABILITY WILL
INTERSECT INCREASING UPPER LEVEL DYNAMICAL SUPPORT AHEAD OF APPROACHING
COLD FRONT. LOCALLY HEAVY RAINFALL WILL CONTINUE TO BE POSSIBLE IN SHOWERS
AND TSTORMS WITHIN THE WARM SECTOR ENVIRONMENT AS THE WARM FRONT LIFTS
NORTHWARD THROUGH MIDDAY OVER SE GA. DESPITE MOSTLY CLOUDY SKIES TEMPS
WILL WARM INTO THE 70S TODAY WITH ANONYMOUSLY HIGH DEW PTS IN THE MID/UPPER
60S WHICH WILL MAKE FOR UNSEASONABLY HUMID CONDITIONS.
THIS AFTN & TONIGHT...THE WARM FRONT IS EXPECTED TO BE ALONG OR JUST
NORTH OF THE ALTAMAHA RIVER BASIN THIS AFTN WITH INCREASINGLY HEAVY
AND WIDESPREAD RAINFALL ENCROACHING UPON THE SUWANNEE RIVER VALLEY
AND INLAND SE GA AS THE FRONTAL SYSTEM APPROACHES FROM THE WEST. THE
CONCERT OF INSTABILITY WITHIN THE WARM SECTOR AND LOW LEVEL JET DYNAMICS
UNDER DIVERGENT UPPER LEVEL FLOW WILL GRADUALLY SHIFT SLOWLY EASTWARD
THIS AFTN THROUGH TONIGHT WITH A TIGHT PRECIP CHANCE GRADIENT ACROSS
OUR FORECAST AREA. ADVERTISED 80% OR GREATER RAIN CHANCES FOR INLAND
SE GA TO THE SUWANNEE RIVER VALLEY BY MID AFTN TODAY THROUGH MUCH
OF TONIGHT. THIS TIME PERIOD IS WHEN THE HEAVIEST RAINFALL IS EXPECTED
DUE TO TRAINING OF CELLS REDEVELOPING FROM THE GULF COAST REGION WITH
WIDESPREAD RAINFALL AMOUNTS OF 3-5 INCHES POSSIBLE THROUGH WED NIGHT.
CONTINUED TO REFRAIN FROM A FLOOD WATCH UNTIL CONVECTIVE TRENDS BECOME
MORE ESTABLISHED.
WED...THE HEAVY PRE-FRONTAL PRECIP SHIELD WILL FINALLY BEGIN TO
TRANSLATE DOWNSTREAM ACROSS THE REMAINDER OF THE FORECAST AREA WED
MORNING AS THE PARENT UPPER LEVEL LOW TRACKS FARTHER EAST...BUT
THE TRAILING UPPER LEVEL TROUGH IS NOW PROGGED TO REMAIN NEG
TILTED WHICH FAVORS A SLOWER PASSAGE OF PRECIP ACROSS THE LOCAL
FORECAST WED AFTN INTO WED NIGHT. THERE REMAINS A LOW CHANCE OF
ISOLATED SEVERE STORMS WED ESPECIALLY ACROSS THE SUWANNEE RIVER
VALLEY OF NE FL BY EARLY AFTERNOON WHERE GULF INSTABILITY WILL
SURGE INLAND JUST AHEAD OF THE APPROACHING COLD FRONT AND JET
DYNAMICS PHASE. THE MAIN CONVECTIVE HAZARD WILL BE GUSTY WINDS OF
40-60 MPH BUT A FEW ROTATING CELLS MAY DEVELOP GIVEN STRONG
DIRECTIONAL SHEAR.
WED NIGHT...THE GFS IS STARTING TO HINT AT THE JAX SPLIT SCENARIO
IN PRECIP WED EVENING AS DYNAMICS EJECT OFF TO THE NE AND INSTABILITY
HUGS THE GULF COAST REGION. INDICATED THIS TREND IN THE LATEST
FORECAST WITH HIGHER RAIN CHANCES ALONG THE ATLANTIC COAST WED
EVENING AND GULF COAST AREAS WITH TSTORM POTENTIAL ENDING FROM NW-
SE THROUGH MIDNIGHT. LINGERING POST- FRONTAL SHOWERS STILL
EXPECTED EARLY THU WITH LAGGING MID LEVEL TROUGH AXIS. TEMPS WILL
COOL THROUGH WED NIGHT INTO THE UPPER 40S OVER INLAND SE GA TO THE
LOW/MID 50S OVER NE FL WHERE LINGERING PRECIP/CLOUDS ARE EXPECTED
AFTER MIDNIGHT.
CHRISTMAS DAY...SURFACE HIGH PRESSURE WILL BUILD INTO THE AREA
WITH DECREASING CLOUDINESS THURSDAY MORNING. DRIER AND COOLER
CONDITIONS WILL PREVAIL WITH LIGHT WINDS AND NEAR AVERAGE
TEMPERATURES.
.LONG TERM...FRIDAY THROUGH MONDAY...SURFACE HIGH MOVES OFF THE
EAST COAST FRIDAY WITH A RETURN FLOW BRINGING BACK MOISTURE. AN
ACTIVE SW FLOW ALOFT WILL BRING ANOTHER FRONTAL SYSTEM INTO THE SE
THIS WEEKEND INTO EARLY NEXT WEEK. MODEL DIFFERENCES PERSIST WITH
THE ECMWF KEEPING MOST OF PRECIP NORTH OF OUR AREA WHILE THE GFS
AND GFS ENSEMBLE BRINGS RAIN FURTHER SOUTH ACROSS SE GA. HAVE CHANCE
POPS MAINLY I-10 NORTHWARD WITH SLIGHT CHANCE TO THE SOUTH STARTING
SATURDAY. TEMPERATURES WILL BE NEAR AVERAGE ON FRIDAY AND THEN
SEVERAL DEGREES ABOVE AVERAGE INTO EARLY NEXT WEEK.
&&
.AVIATION...WAVES OF MVFR TO IFR CONDITIONS WILL CONTINUE TO LIFT
NORTH OF JAX/CRG/VQQ THIS MORNING WITH LIFR AT SSI EXPECTED TO
IMPROVE OVER THE NEXT SEVERAL HOURS TO MVFR THROUGH MIDDAY. EXPECT
PREVAILING VFR AT THE TERMINALS MIDDAY TODAY THROUGH EARLY AFTN
HOWEVER PERIODS OF MVFR TO IFR WILL BE POSSIBLE IN PASSING CONVECTION.
CONDITIONS WILL DETERIORATE GRADUALLY TONIGHT FROM W-E AS PRE-
FRONTAL WIDESPREAD RAINFALL FORMS ACROSS THE PANHANDLE AND INLAND
SE GA WITH PREVAILING MVFR LIKELY DEVELOPING OVERNIGHT TONIGHT.
&&
.MARINE...A WARM FRONT WILL GRADUALLY LIFT NORTHWARD OVER
SOUTHEAST GEORGIA THIS MORNING. SOUTH WINDS WILL INCREASE LATE
TONIGHT AHEAD OF A COLD FRONT WITH ADVISORY CONDITIONS EXPECTED
OVER THE OFFSHORE WATERS WITH SOUTH WINDS 20 KTS INCREASING TO
20-25 KTS WED. ISSUED A SMALL CRAFT ADVISORY FROM 08Z WED THROUGH
16Z THU. WAVES OF HEAVY RAINFALL AND ISOLATED STRONG THUNDERSTORMS
ARE EXPECTED UNTIL A COLD FRONT PUSHES ACROSS THE WATERS WEDNESDAY
NIGHT. WINDS AND SEAS WILL QUICKLY RELAX THURSDAY AFTERNOON AS
HIGH PRESSURE BUILDS OVER THE EASTERN GULF COAST REGION. THE RIDGE
WILL BUILD NORTHEAST OF THE LOCAL WATERS FRIDAY AND SATURDAY WITH
ONSHORE FLOW EXPECTED.
RIP CURRENTS: LOW RISK TODAY AND AGAIN WEDNESDAY ALTHOUGH
STRONGER LONG SHORE CURRENT WILL BE IN PLACE WED.
&&
.HYDROLOGY...RECENT HEAVY RAINFALL WITHIN THE ST.MARY`S RIVER
BASIN COULD BRING MINOR FLOODING AT MACCLENNY BY THE WEEKEND.
ADDITIONAL RIVERS INCLUDING THE ALAPAHA AND SUWANNEE WILL NEED TO
BE CLOSELY MONITORED GIVEN THEIR PROXIMITY TO THE HIGHER SWATH OF
EXPECTED STORM TOTAL PRECIPITATION.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 71 64 72 49 / 100 100 100 40
SSI 69 63 69 52 / 60 70 100 80
JAX 76 66 75 52 / 90 60 100 80
SGJ 75 67 74 55 / 30 50 100 80
GNV 76 67 74 53 / 30 70 100 70
OCF 78 67 76 54 / 20 60 100 70
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...SMALL CRAFT ADVISORY FROM 3 AM WEDNESDAY TO 11 AM EST THURSDAY
FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM
OFFSHORE-FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM
OFFSHORE-ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM
OFFSHORE.
&&
$$
ENYEDI/ZIBURA
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
1232 AM EST TUE DEC 23 2014
.AVIATION...
FOG DEVELOP IS EXPECTED OVER THE INTERIOR AREAS OF SOUTH FLORIDA
EARLY THIS MORNING WHICH COULD SPREAD INTO THE FAR INTERIOR METRO
AREAS OF SOUTH FLORIDA. THEREFORE...THE CEILINGS SHOULD DROP DOWN
TO NEAR IFR CONDITIONS BETWEEN 9Z AND 12Z THIS MORNING FOR ALL OF
THE TAF SITES. THE VIS WILL ALSO FALL INTO THE MVFR CONDITIONS
BETWEEN 8Z AND 12Z THIS MORNING, EXCEPT FOR KTMB AND KAPF TAF
SITES WHERE THEY WILL FALL DOWN INTO THE IFR CONDITIONS.
THE LOW CLOUDS AND THE FOG SHOULD BURN OFF BY 14Z FOR THE TAF
SITES AS THE FOG BURNS OFF WITH PARTLY CLOUDY SKIES.
THEREFORE..THE CEILING AND VIS WILL BE IN VFR CONDITIONS AFTER 14Z
TODAY. THE WINDS WILL ALSO BE LIGHT AND VARIABLE THROUGH 14Z
BEFORE BECOMING EASTERLY BETWEEN 10 TO 15 KNOTS OVER ALL OF THE
TAF SITES.
&&
.AVIATION...54/BNB
.PREV DISCUSSION... /ISSUED 755 PM EST MON DEC 22 2014/
UPDATE...NO CHANGES TO THE FORECAST THIS EVENING. PWAT ON THE
EVENING MIAMI SOUNDING IS ONLY 1.34 INCHES AND WITH A LACK OF
FORCING, A TRANQUIL NIGHT IS EXPECTED TO CONTINUE. A RATHER MUGGY
LIGHT SOUTHEAST WIND FLOW WILL CONTINUE. READINGS WILL ONLY FALL
A FEW MORE DEGREES AS DEWPOINTS ARE NOW AROUND 70F, SO FORECAST
LOWS CONTINUE TO LOOK IN GOOD SHAPE AND NO CHANGES ARE NECESSARY
THIS EVENING. /GREGORIA
&&
PREV DISCUSSION... /ISSUED 712 PM EST MON DEC 22 2014/
AVIATION...
MAIN CONCERN FOR THIS TAF CYCLE CONTINUES TO BE THE LOW CIG
POTENTIAL ACROSS ALL TAF SITES. SOUTHEAST FLOW SHOULD DECREASE
SLIGHTLY DURING THE OVERNIGHT PERIOD...LESS THAN 10
KNOTS...BEFORE INCREASING AGAIN DURING THE DAY TOMORROW. BELIEVE
THE BIGGEST THREAT FOR LOW CIGS SHOULD BE ACROSS THE INTERIOR AND
GULF COAST MAINLY AFFECTING KAPF. LATEST LAMP GUIDANCE ALONG WITH
THE HRRR IS EVEN SUGGESTING IFR CIGS OVERNIGHT AT KAPF. DECIDED TO
INTRODUCE A TEMPO MENTION FOR BRIEF IFR CIGS AND MVFR VSBY AT KAPF
AS GUIDANCE HAS REMAINED FAIRLY CONSISTENT OVER THE LAST 24 HOURS.
GUIDANCE WAS FAIRLY UNIFORM DEPICTING MVFR CIGS AT ALL EAST COAST
SITES THROUGH MUCH OF THE OVERNIGHT AND EARLY MORNING PERIOD...SO
PREVAILED BKN010-015 AFTER 08Z. COULD SEE BRIEF IFR CIGS AT KTMB
BUT LEFT MENTION OUT OF TAFS FOR NOW.
&&
PREV DISCUSSION... /ISSUED 312 PM EST MON DEC 22 2014/
DISCUSSION...
DRY...WARM AND PARTLY SUNNY CONDITIONS CONTINUE ACROSS SOUTH
FLORIDA THIS AFTERNOON. THE MID/UPPER LEVEL PATTERN CONSISTED OF
A RIDGE OF HIGH PRESSURE CENTERED NEAR THE DOMINICAN REPUBLIC AND
STRETCHING NORTHWARD OVER THE WESTERN ATLANTIC NEAR THE EASTERN
SEABOARD...AND A TROUGH DIGGING INTO THE NORTHERN/CENTRAL PLAINS.
AT THE SURFACE...HIGH PRESSURE WAS OVER THE WESTERN
ATLANTIC...WITH A SOUTHEAST FLOW ACROSS SOUTH FLORIDA. THE
SOUTHEAST FLOW WAS BRINGING INCREASING DEWPOINTS ACROSS THE
REGION...AND TEMPERATURES OVERNIGHT ALONG THE EAST COAST WILL
REMAIN WELL ABOVE NORMAL IN THE LOWER 70S.
AN AMPLIFIED PATTERN WILL REMAIN IN PLACE ON TUESDAY AS THE UPPER
TROUGH DIGS INTO TEXAS AND THE UPPER RIDGE REMAINS OVER THE
CARIBBEAN AND ALONG THE EASTERN SEABOARD. AN AREA OF LOW PRESSURE
IS FORECAST TO DEVELOP ALONG THE NORTHERN GULF COAST...AND THE
PRESSURE GRADIENT WILL INCREASE IN THE AFTERNOON. DRY LOW/MID
LEVEL AIR WILL CONTINUE TO PUSH INTO THE REGION ON
TUESDAY...ROTATING AROUND HIGH PRESSURE OVER THE WESTERN ATLANTIC.
SO ANOTHER DRY...MUGGY AND WARM DAY IS IN STORE FOR SOUTH
FLORIDA...WITH TEMPERATURES IN THE LOW TO MID 80S AND DEWPOINTS
AROUND 70. OVERNIGHT LOWS WILL BE VERY WARM ONCE AGAIN...AND NEAR
RECORD HIGH MINIMUMS IN THE UPPER 60S TO MID 70S.
LOW PRESSURE IS FORECAST TO PUSH INTO THE SOUTHEAST AND THEN OHIO
VALLEY ON WEDNESDAY...WITH TRAILING COLD FRONT PUSHING INTO THE
FLORIDA PENINSULA. MODEL GUIDANCE HAS CONTINUED TO SLOW DOWN THE
TIMING OF THE FRONT...AND IT APPEARS THE FRONT WILL MOVE INTO THE
REGION LATE WEDNESDAY. THE FRONT IS THEN FORECAST TO PUSH THROUGH
THE REGION ON CHRISTMAS MORNING. HOWEVER...MOISTURE WILL LINGER
BEHIND THE FRONT...WITH CLOUD COVER AND SHOWERS REMAINING INTO THE
AFTERNOON HOURS. THE BEST DYNAMICS WILL REMAIN ACROSS CENTRAL
FLORIDA AND THEN OUT INTO THE WESTERN ATLANTIC. INSTABILITY WILL
ALSO BE MARGINAL AS THE FRONT MOVES INTO THE REGION
OVERNIGHT...AND WINDS MAY ALSO VEER TO THE SOUTHWEST AHEAD OF THE
FRONT. SPC HAS THE REGION IN A MARGINAL RISK FOR SEVERE WEATHER.
THE BEST BET FOR STRONGER STORMS APPEARS TO BE FROM NAPLES TO THE
LAKE REGION AND NORTHWARD.
RIDGING WILL HOLD ON OVER THE CARIBBEAN AND BAHAMAS...AND THE
TROUGH WILL LIFT NORTHEASTWARD AND FLATTEN OUT ON THURSDAY. THE
FRONT WILL THEN STALL OVER THE FLORIDA STRAITS THROUGH THE END OF
THE WEEK...WITH HIGH PRESSURE BUILDING INTO THE SOUTHEAST AND THEN
WESTERN ATLANTIC. SO COLD AIR ADVECTION WILL BE SHORT
LIVED...WITH TEMPERATURES ONLY BRIEFING FALLING TO NEAR NORMAL FOR
CHRISTMAS DAY AND FRIDAY.
THE MID/UPPER LEVEL RIDGE IS FORECAST TO BUILD ACROSS THE REGION
OVER THE WEEKEND. MOISTURE WILL QUICKLY RETURN...WITH DEWPOINTS
INCREASING BACK INTO THE MID TO UPPER 60S. TEMPERATURES ARE
FORECAST TO INCREASE TO THE UPPER 70S TO LOWER 80S. A SHORTWAVE
WILL PUSH ACROSS THE FOUR CORNERS REGION ON SATURDAY AND THEN LIFT
NORTHEAST AROUND THE RIDGE OF HIGH PRESSURE INTO THE OHIO VALLEY
ON SUNDAY. A SURFACE LOW IS THEN FORECAST TO PUSH INTO THE
NORTHEAST OR GREAT LAKES...WITH A WEAK FRONT PUSHING INTO
NORTHERN AND CENTRAL FLORIDA BEFORE STALLING.
MARINE...
SOUTHEAST FLOW CONTINUES THROUGH TUESDAY, WITH WINDS VEERING TO
THE SOUTH ON WEDNESDAY. A COLD FRONT WILL APPROACH THE GULF
WATERS WEDNESDAY AFTERNOON, THEN INTO THE ATLANTIC WATERS LATE
WEDNESDAY INTO EARLY CHRISTMAS DAY. NORTHWEST AND NORTH WINDS ARE
EXPECTED BY THURSDAY. SEAS WILL BUILD, ESPECIALLY THROUGH THE
OFFSHORE GULF WATERS WEDNESDAY NIGHT INTO EARLY CHRISTMAS DAY.
HIGH PRESSURE AND NORTHEASTERLY FLOW RETURN TO END THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 74 84 68 74 / 10 20 60 30
FORT LAUDERDALE 75 83 70 75 / 10 20 60 30
MIAMI 73 84 69 76 / 10 20 60 30
NAPLES 69 82 66 71 / 10 50 60 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...84/AK
LONG TERM....23/SK
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
335 AM CST Tue Dec 23 2014
.SHORT TERM...(Today)
ISSUED AT 335 AM CST TUE DEC 23 2014
Initial shortwave associated with a closed low at 500 mb early this
morning was tracking across north central Illinois. Backedge of the
rain has shifted into our east and northeast counties...soon to exit
our area for this morning. Mid level dry slot seen on satellite data
tracking east into parts of west central Illinois. Most of the short
term models shift the lower clouds to our northeast this morning
allowing some breaks to develop. HRRR and RUC soundings showing
the low level moisture slowly lifting with time this morning, but
that shouldn`t last long as mid and high level clouds start to stream
northeast into our area ahead of the second shortwave that will bring
another round of rain, then snow to our area starting tonight. Air
mass in the wake of the weak frontal passage today not very cold at
all, in fact, 925-850 mb temperature forecasts suggests highs this
afternoon will range from the upper 40s north to the middle 50s
southeast.
&&
.LONG TERM...(Tonight through Monday)
ISSUED AT 335 AM CST TUE DEC 23 2014
Will be issuing a Special Weather Statement to address the 1-3inch
snow accumulations with locally 3 to 4 inches west of I-57 to near
the IL river on Wed and Wed evening. 00Z models have trended
further west (especially NAM model) up Indiana Wed with
deformation/trowal setting up over central and northeast IL on Wed.
Rain spread back northward across se IL this evening and over rest
of central IL overnight with chance of light snow late tonight
west of the IL river. But appears warm enough for most areas
tonight to just get rain. Lows tonight in mid 30s from I-55 nw to
upper 30s to around 40F in eastern/southeast IL.
Surface low pressure to deepen and lift nne from the nw Gulf of
Mexico across central Indiana Wed and into eastern lower MI by Wed
evening. Strong upper level low to pivot across IL Wed afternoon
and expect rain to change to wet snow from west to east during the
day Wed. Snow to diminish from west to east during Wed night. Best
snow accumulations to occur over western IL Wed morning with 1
inch or less while snow accumulations 1-3 inches from IL river
east toward I-57 Wed afternoon/evening with locally 3-4 inches
near I-55 and into ne IL. Morning highs Wed in mid to upper 30s
central IL and lower 40s eastern/se IL and then slipping into low
to mid 30s by end of day Wed as strong west/nw winds kick in
during day Wed into Wed night with gusts 25 to 35 mph.
Christmas day still looks dry with return of some sunshine
especially sw counties as strong low pressure exits into Quebec
and 1025 mb surface high pressure sets up over southeast states.
A southerly flow sets up by Thu afternoon with highs in the upper
30s to lower 40s so any snow that fall Wed/Wed evening will likely
melt on Thu afternoon.
Another area of low pressure ejects ne from CO into WI by Fri
evening and swings a cold front se across central IL Fri night and
near southeast IL Sat. Milder highs in mid to upper 40s on Friday
with IL getting in warm sector. Then precipitation chances
increasing during friday night into Sat especially over southeast
IL. Southeast IL looks warm enough for mainly rain (turning to mix
during day on Sat) with mix of light rain/snow central IL but
little accumulations. Highs Sat range from lower 30s nw of IL
river to lower 40s along the Wabash River.
ECMWF model is further north with southern low pressure system and
qpf into southeast IL Sat night through Sunday eve and drawing in
colder air and cold enough for light snow. Have chance of light
snow southeast IL Sat night and Sunday with slight chances over
central IL. Seasonably cold highs in the low to mid 30s on Sunday.
Quieter weather returns early next work week with seasonable temps
for late Dec.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1207 AM CST TUE DEC 23 2014
Clouds continue over the area with rain lifting north. Pcpn will
end, but with lower clouds, light pcpn could hang around for
awhile, so will keep VCSH at all sites overnight. Cig heights will
also lift some as well and become lower level MVFR overnight.
Satellite trends do show clearing across MO and based on HRRR
forecast the clearing gets into the area. But believe mid level
clouds will move into the area behind the clearing area. By
tomorrow afternoon, cigs will drop more and then finally drop back
to MVFR levels ahead of the next system. Winds will be southerly
overnight and then become light and variable tomorrow afternoon
and evening.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Smith
LONG TERM...07
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
219 AM CST TUE DEC 23 2014
.UPDATE...
850 PM CST
NO CHANGES PLANNED TO FORECAST FOR TONIGHT AS UPPER LOW TO OUR
WEST CONTINUES TO DUMBBELL SLOWLY NORTHEAST FROM THE CORN BELT
TOWARD WISCONSIN. ASSOCIATED SFC LOW OVER SOUTHERN IOWA WILL MOVE
NORTHEAST IN CONCERT WITH THE UPPER LOW AND DRAG A WARM FRONT
NORTH ACROSS THE CWA OVERNIGHT INTO EARLY TUESDAY MORNING. THE
RESULT DRIZZLE AND FOG OVERNIGHT PUNCTUATED WITH PERIODS OF RAIN
ALONG WITH SLOWLY RISING TEMPS AS THE DIFFUSE WARM FRONT LIFTS
SLOWLY NORTH. TRENDS IN THE GRIDS ALREADY HAVE A GOOD HANDLE ON
THIS AND NO CHANGES ARE PLANNED.
OF MUCH GREATER CONCERN CONTINUES TO BE THE POTENTIAL FOR A WINTER
STORM AFFECTING PORTIONS OF THE REGION WEDNESDAY...CHRISTMAS EVE
DAY. THE 00Z WRF-NAM IS TRICKLING IN AND APPEARS TO HAVE FINALLY
CAVED IN AND JOINED THE CAMP OF WHAT THE REMAINDER OF THE GLOBAL
MODELS HAD SHOWN ON WITH THE 12Z RUNS. LACK OF RUN-TO-RUN
CONSISTENCY AND HIGH DEGREE OF VARIABILITY BETWEEN VARIOUS MODELS
HAS MADE THIS A CHALLENGING SYSTEM TO FORECAST FOR...HOWEVER THE
12Z GLOBAL MODELS CAME INTO MUCH BETTER AGREEMENT AND NOW THE 00Z
WRF-NAM SEEMS TO HAVE JOINED THAT CAMP WHICH COULD POSE A
SIGNIFICANT WINTER STORM THREAT TO A POTENTIALLY LARGE PORTION OF
OUR CWA WEDNESDAY.
THE EXPLOSIVE DEEPENING OF THE SYSTEM PROGGED IN THE MODELS WITH
500MB...ALONG WITH AMPLE MOISTURE...AND ELEVATED INSTABILITY ALL
LEAVE ME VERY CONCERNED THAT WE COULD BE LOOKING AT A VERY HEAVY
AND WET SNOW AFFECTING THE REGION WEDNESDAY. THE NEGATIVE MID-
LEVEL THETA-E LAPSE RATES AND LAPSE RATES GREATER THAN 6C/KM FROM
600-300MB POINT TOWARD THE POTENTIAL FOR UPRIGHT CONVECTION WITHIN
THE DEFORMATION BAND. THERMAL PROFILES IN THE MODELS ARE MARGINAL
FOR SNOW...ESPECIALLY DOWN LOW...HOWEVER GIVEN THE EXTREMELY
IMPRESSIVE DYNAMICS SHOWN IN THE LATEST GUIDANCE WOULD ANTICIPATE
STRONG ASCENT TO OVERWHELM IN MARGINAL WARMTH DOWN LOW AND LIKELY
ALLOW FOR HEAVY WET SNOW IN THE DEFO BAND.
NOT UNCOMMON FOR RAPIDLY DEEPENING SYSTEMS TO TRACK A BIT FARTHER
WEST THAN MODELS FORECAST...WHICH COULD PUSH THE HEAVY SNOW BAND
FARTHER WEST IN OUR CWA WITH MORE OF A MIX EAST. THE STRONG
FRONTOGENETIC FORCING AND WEAK INSTABILITY WOULD FAVOR A RATHER
NARROW BUT INTENSE BAND OF PRECIPITATION...MAKING THE PLACEMENT OF
ANY HEAVY SNOW BAND VERY DIFFICULT TO PINPOINT.
AM RELUCTANT TO MAKE ANY WHOLE SALE CHANGES TO THE 4TH PERIOD OF
THE FORECAST ON AN EVEN SHIFT FOLLOWING A QUICK GLANCE AT THE
LATEST NAM...HOWEVER IF THE 00Z GLOBAL GUIDANCE COMES IN LOOKING
SIMILAR TO THEIR 12Z RUNS AND ANYTHING LIKE THE 00Z WRF-NAM THEN
THE MIDNIGHT SHIFT WILL PROBABLY NEED TO CONSIDER WINTER STORM
WATCH FOR AT LEAST PORTIONS OF THE AREA. WHILE IT LOOKS TO BE A
VERY HIGH WATER CONTENT SNOWFALL...THE CONVECTIVE ALLOWING MODELS
ARE SPITTING OUT QPF VALUES THAT COULD SUPPORT 6+ INCHES OF SNOW
EVEN WITH SNOW:LIQUID RATIOS AS LOW AS 7-8:1. WILL UPDATE THE SPS
AND HIT THINGS HARDER IN THAT PRODUCT FOR NOW.
IZZI
&&
.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 06Z...
* PRIMARILY IFR CIGS OVERNIGHT...PROBABLY LIFTING TO MVFR OR
POSSIBLY VFR DURING THE DAY.
* PERIODS OF RAIN/DRIZZLE OVERNIGHT THROUGH EARLY MORNING
KJB
//DISCUSSION...UPDATED 06Z...
A SURFACE LOW ACROSS IOWA WILL DRIVE A FRONTAL BOUNDARY NORTHWARD
ACROSS NORTHERN ILLINOIS BY DAYBREAK. ONCE THIS FRONT PASSES...THE
RAIN WILL COME TO AN END. IN FACT...CURRENT REGIONAL RADAR IMAGERY
ALREADY SHOWS THE LAST BATCH OF RAINFALL LIFTING NORTHWARD ACROSS
CENTRAL ILLINOIS. CURRENT TIMING PUTS THE BACK EDGE OF THIS RAIN
THROUGH MOST OF THE TERMINALS BY 10 UTC. CIGS LOOK LIKE THEY WILL
REMAIN IN THE 500 TO 700 FOOT RANGE FOR MUCH OF THE NIGHT.
HOWEVER...CIGS DO LOOK TO IMPROVE DURING THE DAY TODAY...POSSIBLY
TO VFR. OTHERWISE...EXPECT WINDS TO SHIFT SOUTH-SOUTHWESTERLY BY
DAY BREAK AS THE AFOREMENTIONED FRONTAL BOUNDARY LIFTS OVER THE
AREA.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN CIGS THROUGH TONIGHT...DECREASING CONFIDENCE
IN CIGS FORECAST TUESDAY
* MEDIUM-HIGH CONFIDENCE IN PRECIP TRENDS.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...RAIN LIKELY...POSSIBLY CHANGING TO HEAVY WET SNOW. IFR
OR LOWER PROBABLE.
THURSDAY...CHANCE OF MVFR CIGS...MAINLY EARLY.
FRIDAY...CHANCE OF MVFR CIGS. STRONG SOUTH WINDS POSSIBLE.
SATURDAY AND SUNDAY...CHANCE OF MVFR CIGS.
IZZI
&&
.MARINE...
217 AM CST
AN INITIAL AREA OF LOW PRESSURE ACROSS SOUTHERN IOWA THIS
MORNING...WILL SHIFT A WARM FRONTAL BOUNDARY FROM NORTH TO SOUTH UP
THE LAKE DURING THE DAY. THEREFORE...SOME STIFF EASTERLIES WILL
SHIFT SOUTHERLY BY LATE IN THE DAY. FOLLOWING THIS...IT STILL
APPEARS LIKELY THAT A SECOND RATHER SIGNIFICANT STORM SYSTEM WILL
RAPIDLY DEVELOP NEAR THE GULF COAST AND RACE NORTHWARD...WHILE
DEEPENING CONSIDERABLE...ACROSS THE OHIO VALLEY AND OVER THE CENTRAL
GREAT LAKES REGION BY CHRISTMAS EVE. DUE TO THE STRENGTH OF THIS
LOW...IT APPEARS THAT A PERIOD OF GALE FORCE WINDS WILL BE A DECENT
POSSIBLY...ESPECIALLY OVER THE OPEN WATERS CHRISTMAS EVE.
THEREFORE...I HAVE ISSUED A GALE WATCH FOR THE OPEN WATERS OF LAKE
MICHIGAN. DUE TO THE FAST MOVEMENT OF THE STORM...WINDS LOOK TO DROP
BELOW GALE FORCE BY CHRISTMAS DAY. STRONG WINDS AND HIGH WAVES ARE
ALSO EXPECTED OVER THE NEAR SHORE WATERS. HOWEVER...I HAVE OPTED
TO LEAVE THE GALE WATCH OUT OF THE NEAR SHORE WATERS AT THIS
TIME...THOUGH SOME GALES CANT BE RULED OUT.
KJB
&&
.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
1207 AM CST Tue Dec 23 2014
.UPDATE...
ISSUED AT 908 PM CST MON DEC 22 2014
Most of forecast looks ok. However, will have to make some
adjustments to pcpn/pop and possibly low temps tonight. Back edge
of pcpn is on the Miss river and will continue to move northeast
overnight. So will be making minor changes to mentioned items shortly.
&&
.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 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1207 AM CST TUE DEC 23 2014
Clouds continue over the area with rain lifting north. Pcpn will
end, but with lower clouds, light pcpn could hang around for
awhile, so will keep VCSH at all sites overnight. Cig heights will
also lift some as well and become lower level MVFR overnight.
Satellite trends do show clearing across MO and based on HRRR
forecast the clearing gets into the area. But believe mid level
clouds will move into the area behind the clearing area. By
tomorrow afternoon, cigs will drop more and then finally drop back
to MVFR levels ahead of the next system. Winds will be southerly
overnight and then become light and variable tomorrow afternoon
and evening.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Auten
SHORT TERM...Barnes
LONG TERM...Bak
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1212 AM EST Tue Dec 23 2014
...Updated Aviation Discussion...
...Forecast Update...
Issued at 1000 PM EST Mon Dec 22 2014
Good area of rain continues to move northeast over west-central to
north-central KY and south-central IN at this time. This is in
response to strong shortwave tilting negatively to the south and
east of main upper low over central Plains. This shortwave trough
over MO will lift rapidly northeast overnight. The trough is
enhancing forcing over the lower Ohio Valley. Looking at model
soundings and Nashville`s 00 UTC observed sounding, there is a bit
of elevated instability. The combination of forcing and less stable
air aloft is leading to good ascent ahead of the shortwave and the
area of rain, some moderate to isolated heavy, in our forecast area.
As the shortwave lifts northeast, so will the rain. Given the weak
instability aloft and given a few specks of 50 dBZ on radar here and
there, plus a few lightning strikes earlier, will include a slight
chance of thunder overnight, also supported by a 40 kt low-level
jet. Will carry categorical POPs with this feature overnight but
rain should then diminish somewhat toward morning, as supported by
latest HRRR run and as suggested by 00z NAM. Nevertheless, scattered
showers still are expected. Temps won`t dip much overnight, perhaps
a couple degrees then steady. Showers should then pick up again
during the day on Tuesday over central KY.
Issued at 650 PM EST Mon Dec 22 2014
Quick update for latest trends. Central KY and south-central IN has
been largely devoid of precip other than a few sprinkles early this
evening. However, better area of showers is developing and moving
northeast over western parts of KY and TN at this time, with some
briefly heavier cells. This is in response to forcing associated
with tail end of shortwave trough entering MO as the trough rotates
around the underside of the upper low over the central Plains.
As this shortwave moves northeast tonight, the area of showers will
lift northeast as well, spreading across the western half of our
forecast area. The Bluegrass region may stay on eastern fringe of
precip with only scattered showers. Surface winds will pick up a bit
this evening as well, especially along the I-65 corridor in response
to the shortwave rotating through to our west and northwest. This
will keep temps pretty much in check this evening.
.SHORT TERM (Now through Tuesday Night)...
Issued at 310 PM EST Mon Dec 22 2014
Deep upper low is just about to close off over the Northern Plains
this afternoon, with deep=layer S-SW flow increasing over the
Mississippi and Ohio Valleys. This pattern will result in mild but
unsettled weather over the next 36 hrs or so, as a series of
disturbances will touch off rounds of showers.
Moisture transport is just getting established, so the main precip
shield associated with the lead disturbance has remained confined
mainly to the Wabash Valley and points west, with very little in the
way of precip over central Kentucky or southern Indiana. A
smattering of showers did develop over northern Alabama, but not
showing much organization as it lifts through Middle Tennessee.
Still expecting precip to blossom tonight as additional upper waves
interact with a 40-45 kt low-level jet, but QPF looks fairly modest.
Therefore will still carry categorical POPs, even though confidence
in getting any substantial rain amounts is decreasing. An isolated
rumble of thunder still can`t be completely ruled out, but continues
to look less likely as this system appears to come at us in pieces.
Therefore will go forward without mention of thunder at this time.
By daybreak the best feed of deep moisture will be shunted to our
north and east, so would expect a break of a few hours in the precip
Tuesday morning. However the next wave will take shape late in the
day, spreading rain back in from south to north late afternoon/early
evening. Deepening surface low still progged to run up between the
I-65/I-75 corridors, with tremendous bust potential depending on
exactly where it tracks. Categorical POPs and steady temps in the
50s along/east of the track, while farther west, precip chances are
barely 50-60% and temps could drop into the lower 40s by Wednesday
morning. There will be a tight gradient in between but the placement
is a little iffy, and for now we will assume that to be somewhere
near I-65.
.LONG TERM (Wednesday through Monday)...
Issued at 300 PM EST Mon Dec 22 2014
An active long term period with the main forecast challenge being
temperatures and precipitation timing/types Christmas Eve through
Christmas morning, followed by more precipitation chances this
weekend.
The 22.12z guidance is trending toward a similar solution with the
main surface low track Wednesday morning. Outside of the NAM, which
was an eastern outlier, the ECMWF/GFS/GEM show a strengthening low
lifting along a Nashville to Louisville to Indianapolis track during
the course of the day. A time trend analysis shows this is a slight
shift west and about 3-6 hours later than the previous consensus.
The impacts this has to precipitation timing and type were very
minimal, as there has been good consensus for steady rain to move
across the region during the course of the day. However, the change
does allow for warmer air to move through central/eastern Kentucky
and as a result, high temperatures were increased to the mid/upper
50s from the Cumberland to Bluegrass region, including the Lexington
metro area. For the Louisville area, the tighter baroclinic zone
will be right along the I-65 corridor, making Wednesday morning
temperatures difficult to pinpoint at this time. Nonetheless, the
area should warm into the low 50s before cold advection kicks in and
temperatures crash into the low/mid 40s by afternoon. Western
forecast area should see the coolest readings, likely stuck in the
upper 40s, then falling into the upper 30s by mid afternoon.
The main message/impact for the public will be a wet, unsettled
Christmas Eve with falling temperatures during the afternoon. It`ll
also be windy, both ahead and behind the surface low. Not ideal
holiday travel conditions, even if it`s just all liquid.
Soundings show a potential changeover from rain to snow west of I-65
during the evening hours /after 7 pm/. However, the greater
frontogenetical forcing and deformation precipitation band should be
west of the forecast area and we`ll be dealing with scattered, light
precipitation. Will continue to advertise a rain to rain/snow mix to
light snow during the nighttime hours. Little accumulations likely
as wet/warm surfaces and temperatures in the low/mid 30s will limit
accumulations. For Christmas, plan on clearing skies west to east as
a Pacific airmass high pressure quickly builds in from the
southwest. Temperatures will be around normal in the mid 40s.
The weekend forecast has some uncertainty as the whole upper level
flow remains amplified and active across the CONUS. At least
initially, there is some consensus that a surface low lifts through
the Great Lakes Friday night, dragging a cold front through the
local area Saturday. 30-40 percent rain chances look reasonable at
this time. Differences arise between the ECMWF/GFS/GEM as the 22.12z
ECMWF/GEM camp develop a secondary low along the Texas gulf coast
Saturday night, lifting it toward eastern Tennessee Sunday. This
would spread precipitation back across the area. Temperature
profiles this time would support a rain/snow mix for the northwest
half of the forecast area. However, the forecast details, including
any specific storm system/track, beyond Saturday have low confidence
as there are a wide range of solutions in this type of upper level
pattern. Next week looks to featuer similar uncertainity as both
ECMWF and GFS show varying storm systems to possibly impact the
area. An active stretch through the end of the year.
&&
.AVIATION (06Z TAF Update)...
Issued at 1209 AM EST Tue Dec 23 2014
Showers will continue off and on through this TAF period. Through
this morning a shortwave will continue to lift off to the northeast. Winds
at 2 kft will continue to increase to around 40 knots. Though it
will be marginal, have decided to keep LLWS in the TAFs for SDF and
BWG through 09-10Z. Winds aloft will decrease thereafter.
The other challenge for this forecast will be ceilings and
visibility. Visibility will likely bounce between VFR and MVFR as
multiple waves of showers cross the TAF sites. Guidance suggests
that ceilings will continue to lower overnight. SDF and particularly
BWG will likely drop to IFR. Some improvement will be possible at
SDF through the day, but BWG looks to remain IFR throughout after it
drops. LEX is more questionable, so have kept cigs more optimistic
there.
Winds will decrease through the morning hours to less than 7 knots.
An increase is then expected again tonight as a low approaches from
the south.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........TWF
Short Term.....RAS
Long Term......ZBT
Aviation.......EER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
505 AM EST TUE DEC 23 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EST TUE DEC 23 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO
CENTERED NEAR OMAHA BTWN BIG UPR RDG ALONG THE W COAST AND ANOTHER
OFF THE E COAST. THE WRN GREAT LKS ARE UNDER THE SW FLOW ALOFT E OF
THIS FEATURE. WV IMAGERY SHOWS A RATHER IMPRESSIVE SHRTWV LIFTING TO
THE NE THRU IL E OF THE CLOSED LO WITH AREA OF COOLING CLD TOP TEMPS
CORRESPONDING TO WHETHER THE MODELS ARE SHOWING SOME IMPRESSIVE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV. EVEN THOUGH THE
SHARPER DYNAMIC FORCING IS STILL WELL S OF UPR MI EARLY THIS MRNG...
SOME LIGHT SN INVADED THE AREA LAST EVNG UNDER SOME DEEP ISENTROPIC
ASCENT/DEEP SATURATION SHOWN ON THE 00Z GRB RAOB /00Z PWAT WAS 0.57
INCH OR 225 PCT OF NORMAL AT GRB/WELL TO THE NE OF THE CLOSED LO.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS MAINLY ON POPS/QPF/PTYPE
ASSOCIATED WITH THE STRONG SHRTWV OVER IL THAT WL LIFTING QUICKLY
NNEWD TODAY AND GOING HEADLINES.
TODAY...IL SHRTWV IS FCST TO LIFT NEWD TO NEAR MENOMINEE/ESCANABA BY
18Z AND THEN TO FAR ERN LAKE SUP BY 00Z TUE. SHARP DPVA/DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE IS FCST TO IMPACT THE CWA
THRU THE DAY BEFORE BEGINNING TO SUBSIDE LATE. THE SHARPER FORCING
IS FCST TO GLANCE THE WRN ZNS. MODELS HAVE SHOWN GOOD CONTINUITY IN
FCSTG AN AXIS OF HIER H7 SPECIFIC HUMIDITY ARND 3 G/KG AND AN AXIS
OF SHARPER H85-7 FGEN THAT IS FCST TO ROTATE NWWD AND BE ORIENTED IN
A LINE OVER THE CENTRAL CWA BY 18Z ON THE CYC SIDE OF THE SHRTWV
TRACK. THIS DEFORMATION BAND SHOULD SERVE AS THE FOCUS FOR THE
HEAVIEST PCPN. H7 SPECIFIC HUMIDITY AT 3 G/KG SUPPORTS ABOUT 6
INCHES OF SN IN THE 12HR PERIOD OF EXPECTED FORCING...IN GOOD
AGREEMENT WITH HPC FCST STRIPE OF 4 TO 6 INCHES OF SN OVER THE
CENTRAL CWA. RATHER HI AND THIN DGZ BTWN 10-13K FT WL LIMIT SN/WATER
RATIOS...SO THE SN WL BE WET AND HEAVY. EVENTUAL DRY SLOTTING TO THE
E OF THIS DEFORMATION ZN BY 18Z OVER THE SE AND EXPANDING NEWD THRU
THE AFTN WL LIMIT SN TOTALS IN THAT AREA AS THE PCPN. THERE ARE ALSO
PTYPE CONCERNS...ESPECIALLY OVER THE E HALF. THE 00Z NAM FCST SDNGS
SHOW A BIT OF AN ELEVATED WARM LYR WITH WARM NOSE/H9 TEMP ABOVE 0C
CENTERED ARND H9 MOVING AS FAR W AS IRON MOUNTAIN AND THEN
ENVELOPING MUCH OF THE NCNTRL COUNTIES. GIVEN THE SW-NE FCST TRACK
OF THE SHRTWV WL FOLLOW THE SOMEWHAT COLDER 00Z CNDN MODEL FCST
TEMPS...WHICH IS SUPPORTED BY THE 00Z GFS AND LATEST RAPID REFRESH
MODELS. THESE MODELS HINT THE PCPN WL MIX WITH OR CHANGE TO RA E OF
LINE FM MARQUETTE TO IRON MOUTNAIN...CONSISTENT WITH THE AXIS OF THE
DEFORMATION ZN AND SHARPER UVV ON ITS CYC SIDE THAT WL TEND TO
OFFSET THE WAA. THE ONLY EXCEPTION WL BE NEAR LK SUP FM THE KEWEENAW
TO MARQUETTE...WHERE HIER SFC TEMPS NEAR THE WARMING INFLUENCE OF LK
SUP WL SUPPORT AT LEAST A MIX WITH SOME RA. FOR LOCATIONS AWAY FM
FAR SRN MENOMINEE COUNTY AND THE IMMEDIATE LK MI/BAY OF GREEN BAY
SHORES...THE MIX WITH OR CHANGE TO RA/DZ WL NOT OCCUR UNTIL AFTER
THE HEAVIER DEFORMATION ZN SN BAND HAS LIFTED TO THE NW. ADDED A
MENTION OF SOME FOG LATER TODAY OVER THE E WITH HI LLVL RH/MELTING
SN WITH MAX TEMPS NEAR 35 UNDER SOME MID LVL DRYING. OVERALL... THE
INHERITED HEADLINES WITH ADVYS FOR THE ENTIRE CWA STILL LOOK OKAY.
ALTHOUGH THE SHARPER FORCING WL MISS THE FAR WRN CWA...STILL LOOKING
FOR 2 TO 4 INCHES OF WET SNOW IN THAT AREA...ENUF TO JUSTIFY THE
ADVY.
TNGT...IN THE WAKE OF DEPARTING SHRTWV...DEEP LYR QVECTOR DVGC IS
FCST TO DOMINATE THE CWA...WITH EXPANDING MID LVL DRYING. EXPECT THE
HIER POPS IN THE EVNG OVER THE W UNDER LINGERING DEEPER MSTR. WITH
THE SHALLOW MOIST LYR BLO THE DGZ...NOT OUT OF THE QUESTION THERE
COULD BE SOME FREEZING DZ...ESPECIALLY OVER THE HIER TERRAIN OF THE
NCENTRAL AND W WHERE NNE FLOW WL UPSLOPE AND TEMPS WL BE AOB 32. BUT
RELATIVELY UNSTABLE NATURE OF THE LLVL LAPSE RATES WL LIMIT THIS
POTENTIAL. MIN TEMPS WL BE WELL ABOVE NORMAL FOR THE SEASON...NO
LOWER THAN THE UPR 20S OVER THE INTERIOR W. MAINTAINED MENTION OF
FOG THRU THE NGT OVER THE E HALF WHERE TEMPS ARE LIKELY TO REMAIN
ABOVE 32 WITH MOIST AIR OVER MELTING SN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 503 AM EST TUE DEC 23 2014
FOLLOWED THE ECMWF/GEM FOR THE TRACK OF THE LOW PRESSURE SYSTEM
LIFTING JUST EAST OF LOWER MICHIGAN WEDNESDAY AFTN INTO CHIRSTMAS
EVE. GIVEN THE STRENGTH OF THE JET STREAK UP TO 180 KTS OVER THE
INTERMOUNTAIN WEST AND COULPLE OF STRONGER SHORTWAVES DIGGING INTO
THE BASE OF CNTRL PLAINS TROUGH...THINK GFS AND PARALLEL GFS MODELS
ARE TOO QUICK TO BRING THE SHORTWAVE NORTH TO MICHIGAN ON WEDNESDAY
WHICH ALSO PUSHES THE LOW FARTHER TO THE WEST COMPARED TO OTHER
MODELS. 00Z NAM WAS ON THE SLOWER SIDE BUT WOULD TEND TO BUY THAT
IDEA GIVEN HOW FAR SOUTH THIS WAVE WILL INITIALLY DIG INTO TX BEFORE
LIFTING BACK TO THE NORTH. ESSENTIALLY ECMWF/GEM AND NAM IDEAS KEEP
BULK OF DEFORMATION PRECIP JUST NORTHWEST OF SFC-H85 LOWS...MAINLY
IN THE FORM OF SNOW...JUST EAST OF THE CWA. FOR THE POPS/QPF/SNOW
FOLLOWED CLOSELY TO THE WPC GUIDANCE WHICH RESULTED IN CATEGORICAL
POPS FOR LUCE COUNTY LATE WEDNESDAY AFTN INTO CHRISTMAS EVE. HIGH
POPS TAPER QUICKLY TO THE WEST MORE INTO THE CENTRAL CWA.
FOR MOST OF THE CWA ON WEDNESDAY...MAIN CONCERN WILL BE LINGERING
LGT SNOW IN WAKE OF THE SYSTEM MOVING THROUGH TODAY. SOUNDINGS STILL
SHOWING DZ/FZDZ SIGNAL AS WELL WITH MOISTURE UP TO AROUND -7C AND
DRYING ABOVE. HIT THE SNOW AND DRIZZLE CHANCES HARDEST WHERE
NORTHERLY WINDS PROVIDE ADDITIONAL UPSLOPE LIFTING...SO MAINLY OVER
PORTIONS OF WEST AND NCNTRL UPR MICHIGAN. PASSAGE OF WEAK NORTHERN
STREAM WAVE WITH DEEPER MOISTURE LIKELY ENDS THE FZDZ/DZ REGIME BY
CHRISTMAS EVE EVENING. AS LONG AS LOW PRESSURE SYSTEM OVER CNTRL
GREAT LAKES DOES NOT COME ANY FARTHER WEST...WILL SEE ANY LGT SNOW
TAPERING OFF BY MIDNIGHT FOR FAR EAST. TOTAL SNOW ACCUMS AS IT
STANDS NOW COULD BE A FEW INCHES TOWARD KERY. THIS IDEA MATCHES WPC
SNOW FORECASTS FAIRLY WELL. TEMPS THROUGOUT THE WED-WED NIGHT TIME
FRAME REMAIN MILD WITH LOW TO MID 30S ON WED AND UPR 20S TO LOW 30S
WED NIGHT.
ON CHRISTMAS DAY...A COOLISH AIRMASS ALOFT /H85 TEMPS -10C/ IN WAKE
OF THE NORTHERN STREAM TROUGH MAY RESULT IN WEAK LAKE ENHANCED SNOW
FOR WNW FLOW AREAS...BUT OTHERWISE APPEARS TO BE A QUIET DAY WITH
CONTINUED ABOVE NORMAL TEMPS IN THE LOW-MID 30S. TIGHTER PRESSURE
GRADIENT ON WEST EDGE OF DEEPENING LOW LIFTING TOWARD JAMES BAY MAY
LEAD TO SOME GUSTY WINDS AND BLSN OVER FAR EAST CWA TO START THE
DAY...BUT THIS SHOULD EASE QUICKLY.
ON TO THE NEXT SYSTEM THAT COULD IMPACT THE UPPER GREAT LAKES. TREND
OF DEEPER/SLOWER SHORTWAVE TROUGH OVER CNTRL CONUS BY FRIDAY IS
EMERGING. RESULT IS MORE DEVELOPED SFC LOW PRESSURE SYSTEM AND AREA
OF LGT TO MODERATE SNOW ORIENTED SW-NE ON NORTHWEST SIDE OF H85 LOW.
MIXING RATIOS INTO THE SYSTEM A SHADE OVER 2 G/KG AND SLR/S WILL BE
HIGHER AS COLDER AIR WILL HAVE WORKED FM THE NORTHERN PLAINS TO THE
UPPER GREAT LAKES. OVERALL A SWATH OF MODERATE SNOW MAY OCCUR...
PEGGED TO MAINLY IMPACT WESTERN SECTIONS OF UPR MICHIGAN FRIDAY
AFTN/FRIDAY NIGHT. ONSHORE FLOW AND TEMPS COLD ENOUGH COULD LEAD TO
LAKE ENHANCEMENT OVER WESTERN TIER OF UPR MICHIGAN FOR AREAS FAVORED
BY NW WINDS. WILL CONTINUE TO MENTION IN THE HWO.
LAKE EFFECT LIKELY IN THE WAKE OF THIS SYSTEM AS TEMPS CONTINUE TO
COOL WITH READINGS BLO -15C BY LATE IN THE WEEKEND. BLYR DRYING OUT
AND INCREASING SFC RIDGING WILL LIKELY PUT CRIMP INTO THE LES. KEPT
POPS SIMILAR TO PREVIOUS FORECAST FOR THE WEEKEND...WITH LIKELY POPS
IN THE NW FLOW AREAS NEAR LK SUPERIOR. AFTER THE MILD DAYTIME TEMPS
THIS WEEK...THE COOLING TEMPS WILL BE NOTICABLE WITH READINGS ONLY
IN THE TEENS TO LOWER 20S BY SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 723 PM EST MON DEC 22 2014
DRIER AIR MOVING INTO THE AREA IN A SE FLOW HAS ALLOWED FOR A
TEMPORARY IMPROVEMENT IN CIGS EARLY THIS EVENING AT THE TAF SITES
WITH KSAW AND KIWD IMPROVING TO VFR. EXPECT CONDITIONS TO SLOWLY
DETERIORATE LATE TONIGHT AS SNOW WORKS INTO THE AREA OVERNIGHT INTO
TUESDAY WITH A LOW PRESSURE SYSTEM LIFTING 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 HEAVIER SNOW WITH CONDITIONS LOWERING TO LIFR BY LATE
TUE MORNING AT ALL TAF SITES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EST TUE DEC 23 2014
LOW PRESSURE SLOWLY LIFTING OVER THE WESTERN GREAT LAKES TODAY WILL
RESULT IN EAST WINDS ON LK SUPERIOR...PERHAPS GUSTING TO GALE FORCE
OVER WESTERN LK SUPERIOR. WINDS WILL DIMINISH TONIGHT INTO WEDNESDAY
AS THE LOW SLIDES DIRECTLY OVER LAKE SUPERIOR. AS THE LOW WEAKENS...
ANOTHER MUCH STRONGER DEEPENING LOW WILL LIFT NORTHWARD OVER THE
CENTRAL GREAT LAKES BY WEDNESDAY NIGHT. EXPECT NORTHERLY WINDS TO
INCREASE TO 30 KTS OVER EASTERN LK SUPERIOR CLOSER TO THE STRONG LOW
PRESSURE SYSTEM. THE PRESSURE GRADIENT WILL BE TIGHEST ON THE WEST
FLANK OF THIS LOW LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING.
GALE GUSTS COULD OCCUR OVER EASTERN LK SUPERIOR AT THAT TIME. WINDS
BACK NW ON THURSDAY AND DIMINISH TO LESS THAN 20 KTS BY AFTN AS THE
LOW PRESSURE SYSTEM MOVES FARTHER AWAY FM THE AREA. ANOTHER LOW
PRESSURE SYSTEM WILL SLIDE OUT OF THE PLAINS OVER THE UPPER GREAT
LAKES FRIDAY INTO SATURDAY. NORTHERLY WINDS WILL BACK NORTHWEST AND
MAY REACH 30 KTS ON SATURDAY...MAINLY OVER EAST HALF OF LK SUPERIOR.
WINDS DIMINISH AGAIN BY SUNDAY AS HIGH PRESSURE BEGINS TO BUILD
TOWARD THE REGION FM THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>007-009>011-084-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ012>014.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...VOSS
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
500 AM EST TUE DEC 23 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EST TUE DEC 23 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO
CENTERED NEAR OMAHA BTWN BIG UPR RDG ALONG THE W COAST AND ANOTHER
OFF THE E COAST. THE WRN GREAT LKS ARE UNDER THE SW FLOW ALOFT E OF
THIS FEATURE. WV IMAGERY SHOWS A RATHER IMPRESSIVE SHRTWV LIFTING TO
THE NE THRU IL E OF THE CLOSED LO WITH AREA OF COOLING CLD TOP TEMPS
CORRESPONDING TO WHETHER THE MODELS ARE SHOWING SOME IMPRESSIVE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV. EVEN THOUGH THE
SHARPER DYNAMIC FORCING IS STILL WELL S OF UPR MI EARLY THIS MRNG...
SOME LIGHT SN INVADED THE AREA LAST EVNG UNDER SOME DEEP ISENTROPIC
ASCENT/DEEP SATURATION SHOWN ON THE 00Z GRB RAOB /00Z PWAT WAS 0.57
INCH OR 225 PCT OF NORMAL AT GRB/WELL TO THE NE OF THE CLOSED LO.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS MAINLY ON POPS/QPF/PTYPE
ASSOCIATED WITH THE STRONG SHRTWV OVER IL THAT WL LIFTING QUICKLY
NNEWD TODAY AND GOING HEADLINES.
TODAY...IL SHRTWV IS FCST TO LIFT NEWD TO NEAR MENOMINEE/ESCANABA BY
18Z AND THEN TO FAR ERN LAKE SUP BY 00Z TUE. SHARP DPVA/DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE IS FCST TO IMPACT THE CWA
THRU THE DAY BEFORE BEGINNING TO SUBSIDE LATE. THE SHARPER FORCING
IS FCST TO GLANCE THE WRN ZNS. MODELS HAVE SHOWN GOOD CONTINUITY IN
FCSTG AN AXIS OF HIER H7 SPECIFIC HUMIDITY ARND 3 G/KG AND AN AXIS
OF SHARPER H85-7 FGEN THAT IS FCST TO ROTATE NWWD AND BE ORIENTED IN
A LINE OVER THE CENTRAL CWA BY 18Z ON THE CYC SIDE OF THE SHRTWV
TRACK. THIS DEFORMATION BAND SHOULD SERVE AS THE FOCUS FOR THE
HEAVIEST PCPN. H7 SPECIFIC HUMIDITY AT 3 G/KG SUPPORTS ABOUT 6
INCHES OF SN IN THE 12HR PERIOD OF EXPECTED FORCING...IN GOOD
AGREEMENT WITH HPC FCST STRIPE OF 4 TO 6 INCHES OF SN OVER THE
CENTRAL CWA. RATHER HI AND THIN DGZ BTWN 10-13K FT WL LIMIT SN/WATER
RATIOS...SO THE SN WL BE WET AND HEAVY. EVENTUAL DRY SLOTTING TO THE
E OF THIS DEFORMATION ZN BY 18Z OVER THE SE AND EXPANDING NEWD THRU
THE AFTN WL LIMIT SN TOTALS IN THAT AREA AS THE PCPN. THERE ARE ALSO
PTYPE CONCERNS...ESPECIALLY OVER THE E HALF. THE 00Z NAM FCST SDNGS
SHOW A BIT OF AN ELEVATED WARM LYR WITH WARM NOSE/H9 TEMP ABOVE 0C
CENTERED ARND H9 MOVING AS FAR W AS IRON MOUNTAIN AND THEN
ENVELOPING MUCH OF THE NCNTRL COUNTIES. GIVEN THE SW-NE FCST TRACK
OF THE SHRTWV WL FOLLOW THE SOMEWHAT COLDER 00Z CNDN MODEL FCST
TEMPS...WHICH IS SUPPORTED BY THE 00Z GFS AND LATEST RAPID REFRESH
MODELS. THESE MODELS HINT THE PCPN WL MIX WITH OR CHANGE TO RA E OF
LINE FM MARQUETTE TO IRON MOUTNAIN...CONSISTENT WITH THE AXIS OF THE
DEFORMATION ZN AND SHARPER UVV ON ITS CYC SIDE THAT WL TEND TO
OFFSET THE WAA. THE ONLY EXCEPTION WL BE NEAR LK SUP FM THE KEWEENAW
TO MARQUETTE...WHERE HIER SFC TEMPS NEAR THE WARMING INFLUENCE OF LK
SUP WL SUPPORT AT LEAST A MIX WITH SOME RA. FOR LOCATIONS AWAY FM
FAR SRN MENOMINEE COUNTY AND THE IMMEDIATE LK MI/BAY OF GREEN BAY
SHORES...THE MIX WITH OR CHANGE TO RA/DZ WL NOT OCCUR UNTIL AFTER
THE HEAVIER DEFORMATION ZN SN BAND HAS LIFTED TO THE NW. ADDED A
MENTION OF SOME FOG LATER TODAY OVER THE E WITH HI LLVL RH/MELTING
SN WITH MAX TEMPS NEAR 35 UNDER SOME MID LVL DRYING. OVERALL... THE
INHERITED HEADLINES WITH ADVYS FOR THE ENTIRE CWA STILL LOOK OKAY.
ALTHOUGH THE SHARPER FORCING WL MISS THE FAR WRN CWA...STILL LOOKING
FOR 2 TO 4 INCHES OF WET SNOW IN THAT AREA...ENUF TO JUSTIFY THE
ADVY.
TNGT...IN THE WAKE OF DEPARTING SHRTWV...DEEP LYR QVECTOR DVGC IS
FCST TO DOMINATE THE CWA...WITH EXPANDING MID LVL DRYING. EXPECT THE
HIER POPS IN THE EVNG OVER THE W UNDER LINGERING DEEPER MSTR. WITH
THE SHALLOW MOIST LYR BLO THE DGZ...NOT OUT OF THE QUESTION THERE
COULD BE SOME FREEZING DZ...ESPECIALLY OVER THE HIER TERRAIN OF THE
NCENTRAL AND W WHERE NNE FLOW WL UPSLOPE AND TEMPS WL BE AOB 32. BUT
RELATIVELY UNSTABLE NATURE OF THE LLVL LAPSE RATES WL LIMIT THIS
POTENTIAL. MIN TEMPS WL BE WELL ABOVE NORMAL FOR THE SEASON...NO
LOWER THAN THE UPR 20S OVER THE INTERIOR W. MAINTAINED MENTION OF
FOG THRU THE NGT OVER THE E HALF WHERE TEMPS ARE LIKELY TO REMAIN
ABOVE 32 WITH MOIST AIR OVER MELTING SN.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 511 PM EST MON DEC 22 2014
HIGHS WILL REMAIN IN THE 30S THROUGH THE DAY FRIDAY...WITH PLENTY OF
GOING ON PRECIP WISE THIS PERIOD. SLUSHY TO WET ROADWAYS WILL GREET
HOLIDAY TRAVELERS THROUGH FRIDAY...UNLESS A QUICK BURST OF SNOW
OCCURS.
INITIALLY HAVE THE EXITING SFC LOW SHIFTING FROM WI AT 00Z
WEDNESDAY...SHIFTING ACROSS LAKE MI OVERNIGHT INTO
WEDNESDAY...BECOMING A PART OF THE NEXT LOW NEARING FROM THE TN
VALLEY WEDNESDAY MORNING. DRIZZLE/FREEZING DRIZZLE WILL LINGER
THROUGH WEDNESDAY OVER THE E THIRD OF THE CWA...BEFORE CHANGING TO
SNOW LATE IN THE DAY.
ALTHOUGH THERE ARE STILL SOME DISCREPANCIES IN EVEN THE WEDNESDAY
NIGHT FCST...I DID TAKE OUT THE MENTION OF THE LOW PUSHING NORTHWARD
OVER E LOWER MI AND LAKE HURON LATE WEDNESDAY INTO WEDNESDAY EVENING
FOR THE EAST HALF OF UPPER MICHIGAN IN THE HWO. THE 22/00Z ECMWF IS
STRONGER/MORE WRAPPED UP...AND AS A RESULT KEEPS WRAP AROUND PRECIP
WEDNESDAY NIGHT INTO THURSDAY OVER OR JUST E OF THE CWA. THE 22/12Z
RUN WAS SLOWER...AND STILL KEPT MUCH OF THE PRECIP AROUND LUCE
COUNTY AND E. THE 18Z GFS WENT BACK TO A SLIGHTLY MORE W IDEA WITH
THE PRECIP. STILL LOOKS LIKE THE COUNTIES ALONG LAKE MI...AND LUCE
COUNTY WILL BE THE MAIN IMPACTS...WITH SOME LAKE ENHANCEMENT OVER N
CENTRAL UPPER MI. IF THE 18Z GFS PANS OUT...MORE SIGNIFICANT CHANGES
BACK TO OUR PREVIOUS FCST/HWO DISCUSSION WILL BE NEEDED. THE 12Z
RUNS HOWEVER WERE MORE CONSISTENT ON KEEPING THE WIDESPREAD PRECIP E.
LOW PRESSURE TRACKING NORTHEASTWARD FROM THE CENTRAL PLAINS THURSDAY
NIGHT THROUGH THE UPPER GREAT LAKES LATE FRIDAY AFTERNOON AND FRIDAY
NIGHT WILL BRING THE POTENTIAL FOR WIDESPREAD LIGHT TO MODERATE
SNOWFALL TO ALL OF UPPER MICHIGAN. THERE IS STILL PLENTY OF
DISCREPANCY...WITH THE 22/12Z ECMWF KEEPING MUCH OF THE PRECIP OVER
THE W THIRD TO HALF OF THE CWA. THE GFS IS A BIT MORE
GENEROUS...WITH A HEALTHY SWATH OF 0.1IN LIQUID. ADDED THE LIGHT TO
MODERATE SNOW POTENTIAL TO THE HWO FOR HOLIDAY TRAVELERS. RAIN MAY
MIX IN OVER LAKE MI FRIDAY AFTERNOON...BEFORE MUCH COOLER AIR PUSHES
IN ACROSS THE ENTIRE AREA FRIDAY NIGHT. 850MB TEMPS W AT 12Z
SATURDAY COULD BE AROUND -16C ON A FAVORABLE NW WIND...EXTENDING
SNOW OVER THE W INTO SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 723 PM EST MON DEC 22 2014
DRIER AIR MOVING INTO THE AREA IN A SE FLOW HAS ALLOWED FOR A
TEMPORARY IMPROVEMENT IN CIGS EARLY THIS EVENING AT THE TAF SITES
WITH KSAW AND KIWD IMPROVING TO VFR. EXPECT CONDITIONS TO SLOWLY
DETERIORATE LATE TONIGHT AS SNOW WORKS INTO THE AREA OVERNIGHT INTO
TUESDAY WITH A LOW PRESSURE SYSTEM LIFTING 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 HEAVIER SNOW WITH CONDITIONS LOWERING TO LIFR BY LATE
TUE MORNING AT ALL TAF SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 PM EST MON DEC 22 2014
A LOW PRESSURE SYSTEM OVER THE MISSOURI RIVER VALLEY WILL LIFT
NORTHEAST ON TUESDAY THROUGH EASTERN UPPER MICHIGAN WHILE
WEAKENING. WINDS WILL TURN TO THE EAST-NORTHEAST TONIGHT AND
CONTINUE THROUGH TUESDAY. WHILE MOST LOCATIONS WILL SEE WINDS IN
THE 20-30KT RANGE...THERE MAY BE A FEW GALE FORCE GUSTS TO 35KTS
OVER WESTERN LAKE SUPERIOR. AS THE LOW CONTINUES TO WEAKEN ON
TUESDAY NIGHT...ANOTHER LOW WILL DEVELOP IN THE LOWER MISSISSIPPI
VALLEY. THIS LOW WILL QUICKLY LIFT NORTHEAST ON
WEDNESDAY...CROSSING LAKE HURON ON WEDNESDAY NIGHT AND MOVING INTO
NORTHERN QUEBEC ON THURSDAY. AT THIS TIME...EXPECT NORTHERLY WINDS
TO STAY BELOW 25KTS OVER LAKE SUPERIOR DURING THAT PERIOD. ANOTHER
LOW WILL TAKE SHAPE IN THE CENTRAL PLAINS ON THURSDAY NIGHT AND
THEN MOVE NORTHEAST THROUGH THE UPPER GREAT LAKES REGION ON FRIDAY
NIGHT. NORTHEAST WINDS UP TO 30 KNOTS ARE EXPECTED FRIDAY NIGHT INTO
SATURDAY BEHIND THIS LOW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>007-009>011-084-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ012>014.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...VOSS
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
426 AM EST TUE DEC 23 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 425 AM EST TUE DEC 23 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO
CENTERED NEAR OMAHA BTWN BIG UPR RDG ALONG THE W COAST AND ANOTHER
OFF THE E COAST. THE WRN GREAT LKS ARE UNDER THE SW FLOW ALOFT E OF
THIS FEATURE. WV IMAGERY SHOWS A RATHER IMPRESSIVE SHRTWV LIFTING TO
THE NE THRU IL E OF THE CLOSED LO WITH AREA OF COOLING CLD TOP TEMPS
CORRESPONDING TO WHETHER THE MODELS ARE SHOWING SOME IMPRESSIVE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV. EVEN THOUGH THE
SHARPER DYNAMIC FORCING IS STILL WELL S OF UPR MI EARLY THIS MRNG...
SOME LIGHT SN INVADED THE AREA LAST EVNG UNDER SOME DEEP ISENTROPIC
ASCENT/DEEP SATURATION SHOWN ON THE 00Z GRB RAOB /00Z PWAT WAS 0.57
INCH OR 225 PCT OF NORMAL AT GRB/WELL TO THE NE OF THE CLOSED LO.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS MAINLY ON POPS/QPF/PTYPE
ASSOCIATED WITH THE STRONG SHRTWV OVER IL THAT WL LIFTING QUICKLY
NNEWD TODAY AND GOING HEADLINES.
TODAY...IL SHRTWV IS FCST TO LIFT NEWD TO NEAR MENOMINEE/ESCANABA BY
18Z AND THEN TO FAR ERN LAKE SUP BY 00Z TUE. SHARP DPVA/DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE IS FCST TO IMPACT THE CWA
THRU THE DAY BEFORE BEGINNING TO SUBSIDE LATE. THE SHARPER FORCING
IS FCST TO GLANCE THE WRN ZNS. MODELS HAVE SHOWN GOOD CONTINUITY IN
FCSTG AN AXIS OF HIER H7 SPECIFIC HUMIDITY ARND 3 G/KG AND AN AXIS
OF SHARPER H85-7 FGEN THAT IS FCST TO ROTATE NWWD AND BE ORIENTED IN
A LINE OVER THE CENTRAL CWA BY 18Z ON THE CYC SIDE OF THE SHRTWV
TRACK. THIS DEFORMATION BAND SHOULD SERVE AS THE FOCUS FOR THE
HEAVIEST PCPN. H7 SPECIFIC HUMIDITY AT 3 G/KG SUPPORTS ABOUT 6
INCHES OF SN IN THE 12HR PERIOD OF EXPECTED FORCING...IN GOOD
AGREEMENT WITH HPC FCST STRIPE OF 4 TO 6 INCHES OF SN OVER THE
CENTRAL CWA. RATHER HI AND THIN DGZ BTWN 10-13K FT WL LIMIT SN/WATER
RATIOS...SO THE SN WL BE WET AND HEAVY. EVENTUAL DRY SLOTTING TO THE
E OF THIS DEFORMATION ZN BY 18Z OVER THE SE AND EXPANDING NEWD THRU
THE AFTN WL LIMIT SN TOTALS IN THAT AREA AS THE PCPN. THERE ARE ALSO
PTYPE CONCERNS...ESPECIALLY OVER THE E HALF. THE 00Z NAM FCST SDNGS
SHOW A BIT OF AN ELEVATED WARM LYR WITH WARM NOSE/H9 TEMP ABOVE 0C
CENTERED ARND H9 MOVING AS FAR W AS IRON MOUNTAIN AND THEN
ENVELOPING MUCH OF THE NCNTRL COUNTIES. GIVEN THE SW-NE FCST TRACK
OF THE SHRTWV WL FOLLOW THE SOMEWHAT COLDER 00Z CNDN MODEL FCST
TEMPS...WHICH IS SUPPORTED BY THE 00Z GFS AND LATEST RAPID REFRESH
MODELS. THESE MODELS HINT THE PCPN WL MIX WITH OR CHANGE TO RA E OF
LINE FM MARQUETTE TO IRON MOUTNAIN...CONSISTENT WITH THE AXIS OF THE
DEFORMATION ZN AND SHARPER UVV ON ITS CYC SIDE THAT WL TEND TO
OFFSET THE WAA. THE ONLY EXCEPTION WL BE NEAR LK SUP FM THE KEWEENAW
TO MARQUETTE...WHERE HIER SFC TEMPS NEAR THE WARMING INFLUENCE OF LK
SUP WL SUPPORT AT LEAST A MIX WITH SOME RA. FOR LOCATIONS AWAY FM
FAR SRN MENOMINEE COUNTY AND THE IMMEDIATE LK MI/BAY OF GREEN BAY
SHORES...THE MIX WITH OR CHANGE TO RA/DZ WL NOT OCCUR UNTIL AFTER
THE HEAVIER DEFORMATION ZN SN BAND HAS LIFTED TO THE NW. ADDED A
MENTION OF SOME FOG LATER TODAY OVER THE E WITH HI LLVL RH/MELTING
SN WITH MAX TEMPS NEAR 35 UNDER SOME MID LVL DRYING. OVERALL... THE
INHERITED HEADLINES WITH ADVYS FOR THE ENTIRE CWA STILL LOOK OKAY.
ALTHOUGH THE SHARPER FORCING WL MISS THE FAR WRN CWA...STILL LOOKING
FOR 2 TO 4 INCHES OF WET SNOW IN THAT AREA...ENUF TO JUSTIFY THE
ADVY.
TNGT...IN THE WAKE OF DEPARTING SHRTWV...DEEP LYR QVECTOR DVGC IS
FCST TO DOMINATE THE CWA...WITH EXPANDING MID LVL DRYING. EXPECT THE
HIER POPS IN THE EVNG OVER THE W UNDER LINGERING DEEPER MSTR. WITH
THE SHALLOW MOIST LYR BLO THE DGZ...NOT OUT OF THE QUESTION THERE
COULD BE SOME FREEZING DZ...ESPECIALLY OVER THE HIER TERRAIN OF THE
NCENTRAL AND W WHERE NNE FLOW WL UPSLOPE AND TEMPS WL BE AOB 32. MIN
TEMPS WL BE WELL ABOVE NORMAL FOR THE SEASON...NO LOWER THAN THE UPR
20S OVER THE INTERIOR W. MAINTAINED MENTION OF FOG THRU THE NGT OVER
THE E HALF WHERE TEMPS ARE LIKELY TO REMAIN ABOVE 32 WITH MOIST AIR
OVER MELTING SN.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 511 PM EST MON DEC 22 2014
HIGHS WILL REMAIN IN THE 30S THROUGH THE DAY FRIDAY...WITH PLENTY OF
GOING ON PRECIP WISE THIS PERIOD. SLUSHY TO WET ROADWAYS WILL GREET
HOLIDAY TRAVELERS THROUGH FRIDAY...UNLESS A QUICK BURST OF SNOW
OCCURS.
INITIALLY HAVE THE EXITING SFC LOW SHIFTING FROM WI AT 00Z
WEDNESDAY...SHIFTING ACROSS LAKE MI OVERNIGHT INTO
WEDNESDAY...BECOMING A PART OF THE NEXT LOW NEARING FROM THE TN
VALLEY WEDNESDAY MORNING. DRIZZLE/FREEZING DRIZZLE WILL LINGER
THROUGH WEDNESDAY OVER THE E THIRD OF THE CWA...BEFORE CHANGING TO
SNOW LATE IN THE DAY.
ALTHOUGH THERE ARE STILL SOME DISCREPANCIES IN EVEN THE WEDNESDAY
NIGHT FCST...I DID TAKE OUT THE MENTION OF THE LOW PUSHING NORTHWARD
OVER E LOWER MI AND LAKE HURON LATE WEDNESDAY INTO WEDNESDAY EVENING
FOR THE EAST HALF OF UPPER MICHIGAN IN THE HWO. THE 22/00Z ECMWF IS
STRONGER/MORE WRAPPED UP...AND AS A RESULT KEEPS WRAP AROUND PRECIP
WEDNESDAY NIGHT INTO THURSDAY OVER OR JUST E OF THE CWA. THE 22/12Z
RUN WAS SLOWER...AND STILL KEPT MUCH OF THE PRECIP AROUND LUCE
COUNTY AND E. THE 18Z GFS WENT BACK TO A SLIGHTLY MORE W IDEA WITH
THE PRECIP. STILL LOOKS LIKE THE COUNTIES ALONG LAKE MI...AND LUCE
COUNTY WILL BE THE MAIN IMPACTS...WITH SOME LAKE ENHANCEMENT OVER N
CENTRAL UPPER MI. IF THE 18Z GFS PANS OUT...MORE SIGNIFICANT CHANGES
BACK TO OUR PREVIOUS FCST/HWO DISCUSSION WILL BE NEEDED. THE 12Z
RUNS HOWEVER WERE MORE CONSISTENT ON KEEPING THE WIDESPREAD PRECIP E.
LOW PRESSURE TRACKING NORTHEASTWARD FROM THE CENTRAL PLAINS THURSDAY
NIGHT THROUGH THE UPPER GREAT LAKES LATE FRIDAY AFTERNOON AND FRIDAY
NIGHT WILL BRING THE POTENTIAL FOR WIDESPREAD LIGHT TO MODERATE
SNOWFALL TO ALL OF UPPER MICHIGAN. THERE IS STILL PLENTY OF
DISCREPANCY...WITH THE 22/12Z ECMWF KEEPING MUCH OF THE PRECIP OVER
THE W THIRD TO HALF OF THE CWA. THE GFS IS A BIT MORE
GENEROUS...WITH A HEALTHY SWATH OF 0.1IN LIQUID. ADDED THE LIGHT TO
MODERATE SNOW POTENTIAL TO THE HWO FOR HOLIDAY TRAVELERS. RAIN MAY
MIX IN OVER LAKE MI FRIDAY AFTERNOON...BEFORE MUCH COOLER AIR PUSHES
IN ACROSS THE ENTIRE AREA FRIDAY NIGHT. 850MB TEMPS W AT 12Z
SATURDAY COULD BE AROUND -16C ON A FAVORABLE NW WIND...EXTENDING
SNOW OVER THE W INTO SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 723 PM EST MON DEC 22 2014
DRIER AIR MOVING INTO THE AREA IN A SE FLOW HAS ALLOWED FOR A
TEMPORARY IMPROVEMENT IN CIGS EARLY THIS EVENING AT THE TAF SITES
WITH KSAW AND KIWD IMPROVING TO VFR. EXPECT CONDITIONS TO SLOWLY
DETERIORATE LATE TONIGHT AS SNOW WORKS INTO THE AREA OVERNIGHT INTO
TUESDAY WITH A LOW PRESSURE SYSTEM LIFTING 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 HEAVIER SNOW WITH CONDITIONS LOWERING TO LIFR BY LATE
TUE MORNING AT ALL TAF SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 PM EST MON DEC 22 2014
A LOW PRESSURE SYSTEM OVER THE MISSOURI RIVER VALLEY WILL LIFT
NORTHEAST ON TUESDAY THROUGH EASTERN UPPER MICHIGAN WHILE
WEAKENING. WINDS WILL TURN TO THE EAST-NORTHEAST TONIGHT AND
CONTINUE THROUGH TUESDAY. WHILE MOST LOCATIONS WILL SEE WINDS IN
THE 20-30KT RANGE...THERE MAY BE A FEW GALE FORCE GUSTS TO 35KTS
OVER WESTERN LAKE SUPERIOR. AS THE LOW CONTINUES TO WEAKEN ON
TUESDAY NIGHT...ANOTHER LOW WILL DEVELOP IN THE LOWER MISSISSIPPI
VALLEY. THIS LOW WILL QUICKLY LIFT NORTHEAST ON
WEDNESDAY...CROSSING LAKE HURON ON WEDNESDAY NIGHT AND MOVING INTO
NORTHERN QUEBEC ON THURSDAY. AT THIS TIME...EXPECT NORTHERLY WINDS
TO STAY BELOW 25KTS OVER LAKE SUPERIOR DURING THAT PERIOD. ANOTHER
LOW WILL TAKE SHAPE IN THE CENTRAL PLAINS ON THURSDAY NIGHT AND
THEN MOVE NORTHEAST THROUGH THE UPPER GREAT LAKES REGION ON FRIDAY
NIGHT. NORTHEAST WINDS UP TO 30 KNOTS ARE EXPECTED FRIDAY NIGHT INTO
SATURDAY BEHIND THIS LOW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>007-009>011-084-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ012>014.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...VOSS
MARINE...SRF
AREA FORECAST DISCUSSION
NWS DULUTH MN
1130 PM CST MON DEC 22 2014
.UPDATE...
ISSUED AT 810 PM CST MON DEC 22 2014
THE PRECIPITATION OVER MUCH OF NORTHLAND HAS DIMINISHED THIS
EVENING AS FORECAST BY MOST OF THE MODELS. THERE STILL REMAINS
AREAS OF LIGHT SNOW AND DRIZZLE...ESPECIALLY OVER OUR WESTERN
ZONES FROM THE BRAINERD LAKES NORTH TO INTERNATIONAL FALLS. HIGH
RES MODELS SUGGEST THIS WILL DECREASE AS WELL OVERNIGHT. THE
SURFACE LOW OVER WESTERN IOWA IS FORECAST TO LIFT TOWARD THE WI/IL
BORDER BY 12Z TUE. AN AREA OF PRECIP WAS MOVING N/NW TOWARD PRICE
COUNTY AND THAT SHOULD CONTINUE TO MOVE NORTH OVERNIGHT. THE
LATEST HRRR DOES WEAKEN THIS AS WELL OVERNIGHT BEFORE A LARGER
MORE INTENSE AREA OF SNOW MOVES IN TUESDAY MORNING. WE WILL NOT
CHANGE THE ADVISORY TIMING...BUT INSTEAD MENTIONED THE TIMING
ISSUES IN OUR VARIOUS PRODUCTS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 346 PM CST MON DEC 22 2014
MAIN FORECAST CONCERNS IN THE SHORT TERM REMAIN FOCUSED AROUND
THE POTENTIAL FOR ACCUMULATING SNOW OVER THE EASTERN HALF OF THE
FORECAST AREA TONIGHT THROUGH THE DAY TUESDAY. THE WINTRY MIX OF
DRIZZLE...RAIN AND SNOW THIS AFTERNOON AND EARLY EVENING WILL
CHANGE OVER TO ALL SNOW LATER TONIGHT. PATCHY FOG...LOCALLY
DENSE...WILL ALSO PERSIST THROUGH TUESDAY.
A WINTER WEATHER ADVISORY CONTINUES FOR PORTIONS OF NW WISCONSIN
FROM LATE THIS EVENING THROUGH LATE TUESDAY NIGHT.
LARGE UPPER LOW WILL ROTATE EWD FROM SE/NE THROUGH IA/SRN MN
TONIGHT AND INTO SRN WI/GREAT LAKES AREA ON TUESDAY. ON THE
LEADING NERN EDGE OF THIS SYSTEM A DRY WEDGE OF AIR IS EXPECTED TO
ROTATE INTO THE SYSTEM OVER LAKE SUPERIOR AND NRN MN TONIGHT. THIS
FEATURE WILL ALLOW MUCH OF THE PRECIP ACROSS NE MN TO CHANGE TO DZ
OR FZDZ...WHILE THE SFC LOW FILLS OUT AT THE BOTTOM OF THE
SYNOPTIC TROUGH AND BEGINS TO LIFT TO THE NE...SNOW AND DZ/RA WILL
PUSH IN FROM THE SOUTH.
AS THE LOW MOVES INTO ERN WI AROUND GREEN BAY A WELL DEFINED
DEFORMATION ZONE IS EXPECTED TO FORM ACROSS NRN WI INTO THE U.P.
AND LAKE SUPERIOR. SNOW WILL BECOME ENHANCED IN THIS AREA DURING
THE DAY TUESDAY. THE MOST FAVORABLE TIME FOR HEAVY SNOW WILL BE
FROM TUE MORNING INTO THE AFTERNOON FROM SHELL LAKE TO ASHLAND AND
AREAS TO THE EAST. HIGH SNOWFALL RATES WILL ALLOW A QUICK 2 TO 4
INCHES TO FALL IN A RELATIVELY SHORT PERIOD OF TIME. TOTAL
SNOWFALL AMTS WILL RANGE FROM 3 TO 5 INCHES ACROSS THE ADVISORY
AREA WITH LOCALLY HIGHER SNOWFALL TO 6 INCHES ALONG THE ELEVATED
REGIONS OF THE SOUTH SHORE. AREAS TO THE WEST ALONG THE I-35
AND HIGHWAY 61 CORRIDORS AND INTO THE TWIN PORTS WILL SEE
SNOWFALL AROUND 1 TO 3 INCHES.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 346 PM CST MON DEC 22 2014
FAIRLY ACTIVE WEATHER PATTERN WILL PERSIST INTO THIS WEEKEND.
WIDESPREAD LIGHT SNOW SHOULD BE WINDING DOWN WEDNESDAY NIGHT AT THE
BEGINNING OF THE EXTENDED PERIODS. LAKE EFFECTS WILL PROVIDE SOME
ENHANCEMENT ALONG THE SOUTH SHORE OF LK SUPERIOR..BUT LACK OF TRUE
ARCTIC AIR SHOULD ACT TO LIMIT OVERALL AMOUNTS.
STRONG SURFACE LOW WILL DEVELOP OVER THE TENNESSEE VALLEY REGION
WEDNESDAY AND MOVE TOWARD LAKE HURON BY THURSDAY MORNING..BUT THIS
LOW IS EXPECTED TO REMAIN SUFFICIENTLY FAR EAST WHERE SENSIBLE
WEATHER EFFECTS ON THE DULUTH CWA WILL BE MINIMAL..IF ANY.
A VERY WEAK DISTURBANCE WILL BRUSH BY NORTHERN MINNESOTA WEDNESDAY
NIGHT/THURSDAY..WHICH MAY BRING A BIT OF LIGHT SNOW ACROSS THE VERY
FAR NORTH. OVERALL HOWEVER..THIS IS REALLY NOT EXPECTED TO BE A BIG
DEAL.
THE BIGGEST POTENTIAL WEATHER SYSTEM DURING THE EXTENDED PERIOD
APPEARS TO BE THE RAPIDLY MOVING S/W TROF THAT IS PROGGED TO MOVE
FROM ERN COLORADO TO THE U.P. OF MICHIGAN FROM LATE THURSDAY NIGHT
THROUGH FRIDAY EVENING. THE FAST MOVEMENT WILL ACT TO LIMIT THE
DURATION OF MODERATE TO STRONG FORCING FOR ASCENT..BUT THERE APPEARS
TO BE SOME SUPPORT FOR THE IDEA OF FRONTOGENESIS ENHANCEMENT
DEPICTED IN THE MEDIUM RANGE MODELS. GIVEN THE CHANGES THAT WERE
OBSERVED IN THE MODEL EVOLUTION FOR THE PREVIOUS TWO SIGNIFICANT
SYSTEMS..CONFIDENCE IS SOMEWHAT LESS THAN NORMAL. DETAILS WILL NEED
TO BE RESOLVED AS THE SYSTEM GETS CLOSER DURING THIS WEEK. WITH THAT
SAID..WITH THE AVAILABLE DATA RIGHT NOW..THIS APPEARS TO HAVE
POTENTIAL FOR A HIGH-END ADVISORY OR LOW-END WARNING TYPE EVENT FOR
SOMEWHERE IN..OR CLOSE TO THE DULUTH CWA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1129 PM CST MON DEC 22 2014
IFR CONDITIONS COVERED THE NORTHLAND LATE THIS EVENING AND WILL
CONTINUE THROUGH MOST OF THE PERIOD. CEILINGS MAY RISE TO LOW END
MVFR AT TIMES TUESDAY AFTERNOON/EVENING.
LOW PRESSURE IN SOUTHWEST IOWA WILL LIFT INTO SOUTHERN WISCONSIN
BY NOON TUESDAY...THEN CONTINUE NORTHEAST. SOME DRIZZLE/LIGHT SNOW
WILL CONTINUE TO BE POSSIBLE OVER NORTHEAST MINNESOTA TONIGHT...BUT
SHOULD DIMINISH IN COVERAGE. SNOW WAS MOVING NORTH THROUGH
NORTHERN WISCONSIN BUT MAY DIMINISH FOR A TIME TONIGHT BEFORE
HEAVIER SNOW MOVES IN TUESDAY MORNING. SOME DRIZZLE/FREEZING
DRIZZLE WILL ALSO BE POSSIBLE AT TIMES.
MORE SIGNIFICANT SNOWFALL WILL DEVELOP OVER MAINLY NORTHERN
WISCONSIN TUESDAY MORNING...THEN DIMINISH LATE TUESDAY AFTERNOON/EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 33 33 28 31 / 70 60 60 10
INL 32 33 27 31 / 80 30 30 20
BRD 32 33 29 32 / 90 60 50 10
HYR 33 34 30 32 / 80 90 60 20
ASX 33 34 31 32 / 80 100 60 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR WIZ002>004-
008-009.
LS...SMALL CRAFT ADVISORY FROM 4 AM TUESDAY TO 4 AM CST WEDNESDAY FOR
LSZ121-142>148.
&&
$$
UPDATE...MELDE
SHORT TERM...BJT
LONG TERM...MILLER
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
148 AM EST TUE DEC 23 2014
.SYNOPSIS...
A SURFACE LOW DEVELOPING OVER THE NORTHERN MIDWEST IN COMBINATION
WITH A LOW MOVING UP THE EAST COAST WILL BRING A PERIOD OF LIGHT
MIXED PRECIPITATION EARLY THIS MORNING...FOLLOWED BY RAIN TODAY
THROUGH WEDNESDAY WITH MOSTLY CLOUDY SKIES. GUSTY WINDS ARE
EXPECTED CHRISTMAS DAY...WITH LINGERING RAIN SHOWERS MIXING WITH
SNOW SHOWERS.
&&
.NEAR TERM /THROUGH TODAY/...
850 PM UPDATE...
OPTED FOR A SHORT TERM SPECIAL WEATHER STATEMENT FOR THE LOWER
TWO-THIRDS OF OUR FORECAST AREA.
RAIN SHOWERS ARE STREAMING INTO NY AND PA ATTM. IN THE NORMALLY
COOLER VALLEY LOCALES AND ON THE HIGH ELEVATIONS, TEMPERATURES ARE
BETWEEN 30 AND 34 DEGREES. THEREFORE ISOLATED LIGHT FREEZING RAIN
IS EXPECTED THROUGH THE EVENING HOURS.
JUDGING BY THE LATEST RAP AND THE CURRENT OBS TREND, TEMPERATURES
SHOULD WARM ABOVE THE FREEZING MARK BY 11 PM OR MIDNIGHT.
150 PM EST UPDATE...
CLOUDS ARE SLOWLY BUT SURELY BREAKING UP ACROSS THE WESTERN HALF
OF THE CWA THIS AFTERNOON. THE SHORTWAVE PASSING TO THE NORTH HAVE
FINALLY MANAGED TO BREAK UP THE CLOUDS AND IT FEELS GREAT TO
FINALLY SEE THE SUN... EVEN IF IT ONLY LASTS FOR A SHORT AMOUNT OF
TIME. SADLY... IT WILL NOT LAST FOR LONG AS OUR NEXT SYSTEM IS
ABOUT TO IMPACT THE REGION.
UNCERTAINTIES STILL EXIST WITH THE FRONT OF OF THE APPROACHING
STORM. ONE BIG FORECAST QUESTION FOR TONIGHT IS WILL TEMPS BE COLD
ENOUGH TO CREATE HAZARDOUS CONDITIONS. TEMPS ATTM ARE FAIRLY
WARM... AS IN 5 TO 10 DEGREES ABOVE FREEZING... EXCEPT FOR THE
HIGHER TERRAIN WHERE TEMPS HAVE RISEN CLOSE TO THE FREEZING MARK.
WE MAY COOL A FEW DEGREES WHEN THE SUN SETS DUE TO LOSS OF DIURNAL
HEATING AND WITH WET BULB EFFECT AS THE PRECIP FALLS... BUT EVEN
THEN WILL BE WARM ADVECTING.
WE DO EXPECT PRECIP TO START TONIGHT IN THE FORM OF A WINTRY MIX
OF FREEZING RAIN/SNOW/RAIN AND MAYBE SLEET. BUT THE OTHER FORECAST
PROBLEM FOR THE NIGHT IS WILL TEMPS AND ROADS STAY COLD ENOUGH
LONG ENOUGH FOR HAZARDOUS CONDITIONS TO DEVELOP FOR A PROLONGED
PERIOD OF TIME. ATTM CONFIDENCE IS NOT HIGH ENOUGH THAT THIS WILL
BE THE CASE. THUS... WE HAVE DECIDED TO NOT ISSUE AN ADVISORY FOR
TONIGHT. BELIEVE IT WOULD BE MORE APPROPRIATE FOR A SPS ISSUANCE
ENVIRONMENT.
BEFORE MIDNIGHT TONIGHT... EXPECT FREEZING RAIN/SNOW MIX. AFTER
MIDNIGHT EXPECT MORE OF WET SNOW EXCEPT FOR THE HIGHEST
ELEVATIONS... THEY MAY SEE MORE OF A VERY LIGHT FREEZING RAIN
THROUGH 4AM. BY 12Z TUESDAY EXPECT MOST ARES TO TRANSITION OVER TO
RAIN.
TEMPS THROUGH LATE TONIGHT ARE EXPECTED TO REMAIN IN THE LOW TO
MID 30S.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
255 PM EST UPDATE...
UNSETTLED WEATHER WILL BE THE MAIN THEME FOR THIS FORECAST PERIOD
AS A SFC LOW/OCCLUDED FRONT SLOWLY PUSHES IT`S WAY ACROSS THE
NORTHEAST.
TUESDAY MORNING... THE FIRST BATCH OF RAIN SHOWERS WITH THE
APPROACHING STORM SYSTEM WILL JUST START TO PUSH INTO THE AREA.
FOR THE MOST PART BY TUESDAY MORNING ALL PRECIP WILL BE RAIN. IF
THERE STILL ANY LINGERING WINTRY PRECIP FROM THE NIGHT BEFORE...
IT WILL QUICKLY TRANSITION OVER TO RAIN BY 15Z TUESDAY. TUESDAY
WILL HAVE FAIRLY LIGHT ACCUMULATIONS AROUND A HALF AN INCH OR LESS.
WAA WILL ALSO CONTINUE PREVAIL OVR THE REGION TUES INTO WED AS WE
REMAIN IN SOUTHERLY FLOW AHEAD OF THE UPPR LVL TROUGH. THIS WILL
RESULT IN UNSEASONABLY WARM TEMPERATURES OVER NY AND PA. TEMPS
WILL RISE INTO THE MID 40S ON TUESDAY AND CONTINUE TO RISE ON WED.
TEMPS ARE EXPECTED TO REACH THE UPPR 40S TO LOW 50S WED
AFTERNOON... THEN RISE INTO THE LOW TO MID 50S BY WED NIGHT. THE
REASON WHY WE WILL CONTINUE TO SEE A RISE IN TEMPS ACROSS THE CWA
WED NIGHT IS BECAUSE WE WILL HAVE A STRONG LLJ AROUND 40 TO 50
KNOTS. NOT ONLY WILL THIS INCREASE THE TEMPS IT WILL SEE A STRONG
INFLUX OF MOISTURE ACROSS THE NORTHEAST. WE ARE EXPECTED TO SEE
PWAT VALUES AROUND 4 STANDARD DEVIATIONS ABOVE NORMAL. THIS WILL
RESULT IN RAIN SHOWERS BECOMING HEAVY AT TIMES.
RAIN SHOWERS ARE EXPECTED TO PREVAIL THROUGH THE WHOLE FORECAST
PERIOD AS THE OCCLUDED FRONT WILL NOT PUSH COMPLETELY THROUGH THE
AREA TILL THURS. DO NOT EXPECT WATER PROBLEMS DUE TO LOW LIQUID
RATIOS IN SNOW PACK ACROSS OVR NY AND PA.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
1 AM UPDATE...
LITTLE CHANGE. FOLLOWED WPC GUIDANCE. FRI/FRI NGT DRY THEN RAIN
MOVES BACK IN LATE SAT THEN CHANGES TO SNOW FROM NW TO SE SUN AND
SUN NGT. MOSTLY DRY MON/TUE. TEMPERATURES ABOVE NORMAL FALLING TO
NORMAL MON/TUE.
PREVIOUS DISCUSSION...
STRONG COLD FRONT PASSES THE REGION THURSDAY MORNING. MODELS ARE
IN REASONABLE AGREEMENT WITH THIS FEATURE AND SUGGEST THE MOST
SIGNIFICANT IMPACT WILL BE SW-W WINDS IN THE STRONG COLD ADVECTION
THURSDAY AFTERNOON. WINDS MAY GUST AT TIMES 35-45 MPH. THERE IS
ALSO A GOOD SIGNAL SHOWING UP FOR A NARROW COLD FRONTAL RAIN BAND
PHENOMENA MOVING THROUGH BETWEEN 12Z-18Z. THIS FEATURE ALONE MAY
CAUSE CONVECTIVE WIND ACCELERATIONS AND SCATTERED DAMAGE/POWER
OUTAGES. LOOKING FOR A NON-DIURNAL TEMPERATURE TREND FROM WEDS
NIGHT-THURSDAY WITH MAXES FOR WEDS/THURS PROBABLY A FEW HOURS
EITHER SIDE OF MIDNIGHT AS STRONG WARM SECTOR SURGES INTO AREA.
OUTSIDE OF THIS FEATURE...THE TEMPERATURES ARE TRENDING SLIGHTLY
WARMER SO A CHANGEOVER FROM PERIODS OF RAIN TO SCATTERED RAIN/SNOW
SHOWERS SEEMS MORE LIKELY THAN A SHARP TURNOVER TO ALL SNOW. IN
FACT...A SIGNIFICANT DRY SLOT MAY CUT PRECIPITATION OFF FOR MUCH
OF THE MORNING BEFORE THE INSTABILITY SHOWERS ASSOCIATED WITH THE
COLD POOL KICK IN FOR THURSDAY AFTERNOON AND NIGHT.
THE REMAINDER OF THE WEEK FEATURES SOME WEAK LAKE EFFECT RESPONSE
MAINLY NORTH OF CENTRAL NY ON FRIDAY...THEN RIDGING AND GENERALLY
NEAR TO ABOVE NORMAL TEMPERATURES INTO SATURDAY. BIG MODEL
DISCREPANCIES THEN CONTINUE TO SHOW UP BETWEEN THE ECMWF AND GFS
WHERE THE ECMWF BRINGS A QUICK TN VALLEY RUNNER TO THE MIDDLE
ATLANTIC COAST BY SUNDAY AFTERNOON. THE GFS AND GEFS ENSEMBLES
FEATURE A MUCH FLATTER SWLY FLOW AND SFC HIGH PRESSURE. THE
CANADIAN GGEM DEFINITELY LEANS WITH THE EURO WITH LOW PRES ON THE
COAST SUNDAY AFTERNOON. AT THIS TIME...WILL BLANKET WITH LOW CHC
POPS FOR SNOW SHOWERS GIVEN THE HIGH LVL OF UNCERTAINTY.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
1230 AM UPDATE...
RAIN OVER THE AREA NOW WILL CONTINUE THROUGH THE FIRST 24 HOURS.
CONDITIONS DROPPING THIS MORNING THEN REMAINING MVFR/IFR.
BGM HAS IFR CIGS AND MVFR VSBYS. EXPECT IT TO CONTINUE INTO TUES
NGT. CIGS WILL BE AT OR CLOSE TO FLIGHT MINIMUMS ESPECIALLY EARLY
THIS MORNING.
AVP AND ITH WILL HAVE CIGS AROUND 1K FT SO IFR/MVFR AND VSBYS
MVFR. SOME IMPROVEMENT TO MVFR FOR AVP AROUND 15Z.
ELM WILL BE MVFR DUE TO CIGS AND VSBYS. EXTRA FUEL WITH ALTERNATE
REQUIRED.
RME/SYR NOW MVFR BUT EXPECTED TO FALL TO IFR CIGS BY 12Z, THEN
STAY LOW.
LLWS MARGINAL WITH 30 KT WINDS AT 2K FT. WITH NO RECENT PIREPS AND
VAD WINDS 20 KTS REMOVED LLWS AT ELM/AVP.
OUTLOOK...
TUE NGT TO WED NGT... MVFR LIKELY...CHANCE IFR. PERIODS OF RAIN.
THU...VFR. VERY WINDY AFTERNOON.
FRI/SAT...VFR. CHC SHRA SAT.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KAH
NEAR TERM...DJP/KAH
SHORT TERM...KAH
LONG TERM...JAB/TAC
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
245 AM EST TUE DEC 23 2014
.SYNOPSIS...A COLD AIR DAMMING RIDGE WILL REMAIN LOCKED IN PLACE
EAST OF THE APPALACHIANS THROUGH THIS AFTERNOON. A WARM FRONT WILL
LIFT NORTHWARD THROUGH THE REGION TONIGHT AND EARLY WEDNESDAY AS A
STRONG COLD FRONT APPROACHES FROM THE WEST. THIS FRONT WILL MOVE
EAST THROUGH OUR REGION WEDNESDAY NIGHT.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 1025 PM MONDAY...
TONIGHT: WV SATELLITE AND UPPER AIR DATA THIS EVENING REVEAL A
STRONGLY DIGGING/AMPLIFYING TROUGH OVER THE EASTERN ROCKIES...WITH
PERTURBED SOUTHWESTERLY FLOW EAST OF THE TROUGH AXIS FROM THE EAST
PACIFIC TO THE EASTERN US COAST. ONE SUCH PERTURBATION AND
ASSOCIATED AREA OF SHOWERS FROM NE GA AND THE SC UPSTATE WILL TRACK
NE ACROSS THE WESTERN PIEDMONT TONIGHT...AND IN CONJUNCTION WITH A
STRONG 925 MB FRONTAL ZONE OVER THE PIEDMONT CHARACTERIZED BY A 13 C
TEMP DIFFERENTIAL BETWEEN GSO AND MHX PER 00Z RAOB DATA...WILL
SUPPORT PERIODS OF RAIN OVER THE WESTERN PIEDMONT. UPSTREAM HOURLY
RAINFALL AMOUNTS SUPPORT THE LATEST RAP AND HRRR QPF OF AROUND A
TENTH TO TWO TENTHS OF ADDITIONAL RAIN...VERSUS LIGHTER AMOUNTS
NOTED BY THE EC/GFS/NAM. OTHERWISE AND ELSEWHERE...PERIODS OF
NORTHERLY 5-10 MPH WIND-BLOWN DRIZZLE...AND A CHANCE OF MEASURABLE
RAIN...WILL PREVAIL. A SATURATED AND NEAR-FULLY WET-BULBED LOWEST
SEVERAL THOUSAND FT...OWING TO CAD FROM A PARENT 1032 MB SURFACE
HIGH NEAR NOVA SCOTIA...WILL SUPPORT LITTLE VARIATION IN
TEMPERATURES FROM THEIR 10 PM READINGS IN THE MIDDLE 30S TO AROUND
40 DEGREES. -MWS
TUESDAY...NO MECHANISM NOTED TO SCOUR OUT THE CAD AIR MASS SO EXPECT
A CONTINUATION OF THE EXTENSIVE OVERCAST WITH PATCHES OF LIGHT
RAIN/DRIZZLE. EXPECT TO SEE A NOTEWORTHY INCREASE IN RAIN COVERAGE
AND INTENSITY LATE IN THE DAY AS S/W (NOW CROSSING CENTRAL TX)
ADVANCES EAST TOWARD OUR REGION. THIS FEATURE WILL INCREASE
DIVERGENCE ALOFT AS WELL AS INCREASE ISENTROPIC UPGLIDE IN THE LOWER
LAYERS OF THE ATMOSPHERE. THESE FACTORS IN COMBINATION WITH PRECIP
WATER VALUES WELL ABOVE NORMAL SHOULD RESULT IN AREAS OF MODERATE-
BRIEFLY HEAVY RAINFALL LATE IN THE DAY OR EARLY EVENING ACROSS THE
WESTERN PIEDMONT.
DAYTIME TEMPS WILL REMAIN WELL BELOW NORMAL. USED THE HIGH RES WRF-
ARW FOR HOURLY TEMPS AS GFS-BASED GUIDANCE APPEARS TO BE ERODING THE
CAD (AND ITS LINGERING EFFECTS) TOO QUICKLY. TEMPS BY LATE AFTERNOON
SHOULD VARY FROM THE UPPER 30S/LOWER 40S OVER THE PIEDMONT TO NEAR
50 OVER THE FAR SE.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 240 AM TUESDAY...
...WARMER... BREEZY... WITH HEAVY RAIN THREAT WEDNESDAY INTO
WEDNESDAY EVENING...
OVERALL... MODELS ARE IN GOOD AGREEMENT WITH THE STORM TRACK TO THE
WEST OF THE APPALACHIANS. WEDNESDAY WILL BEGIN WITH LINGERING CAD IN
THE PIEDMONT DAMMING REGION... BUT A WARM FRONT WILL BE SURGING
NORTHWARD WITH WIDESPREAD RAIN... LOCALLY HEAVY EARLY IN THE DAY.
THE WARM FRONT WILL SURGE INTO VA IN THE AFTERNOON... THEN A LINE OF
CONVECTION CAN BE EXPECTED WITH THE MAIN COLD FRONT LATER IN THE DAY
INTO THE EVENING.
THE AFOREMENTIONED WARM FRONT IS EXPECTED TO BE LIFTING NORTHWARD
THROUGH THE PIEDMONT WEDNESDAY MORNING WITH CATEGORICAL POP. THE NW
QUADRANT OF THE PIEDMONT WILL BE THE LAST REGION TO HANG ON TO THE
RESIDUAL CAD WITH LOW CEILINGS AND VISIBILITIES/COOL STABLE SURFACE
TEMPERATURES BEFORE EVEN THAT REGION BREAKS INTO THE WARM SECTOR
WEDNESDAY AFTERNOON. THERE IS STILL A QUESTION OF TIMING OF THE WARM
FRONT WHICH WILL AFFECT HIGH TEMPERATURES IN THE PIEDMONT WEDNESDAY.
IN ADDITION... SOME ENSEMBLE MEMBERS OF BOTH THE GFS AND EC INDICATE
SHOWERY CONDITIONS AND LOW CEILINGS EVEN AFTER THE WARM FRONT MOVES
INTO VA. HOWEVER... A LULL IN SIGNIFICANT RAINS IS EXPECTED AFTER
THE WARM FRONT IN THE EAST AND SOUTH. HIGHS SHOULD REACH WELL INTO
THE 60S AND EVEN SOME 70S DOWN EAST. SOUTHWEST WINDS WILL INCREASE
TO 10-20 MPH.
A PRE-FRONTAL CONVECTION LINE AND/OR A LINE OF CONVECTION WITH THE
ACTUAL COLD FRONT WILL FOLLOW LATER WEDNESDAY INTO WEDNESDAY EVENING
(PROGRESSING FROM WEST TO EAST ACROSS THE STATE). SOME LOCALLY VERY
HEAVY RAIN CAN BE EXPECTED. A FLASH FLOOD WATCH HAS BEEN CONSIDERED.
HOWEVER... GIVEN THE RELATIVELY DRY ANTECEDENT CONDITIONS...
ESPECIALLY IN THE WEST DURING THE PAST MONTH - FLASH FLOOD GUIDANCE
REMAINED HIGH. THE QPF FOR STORM TOTAL OF 2-3 INCHES WOULD GET MOST
AREAS NEAR THE THRESHOLD. HOWEVER... GIVEN THAT THE HEAVIEST RAIN
SHOULD COME IN 2-3 ROUNDS... THE GROUND SHOULD BE ABLE TO RECOVER
SOMEWHAT IN BETWEEN THE HEAVIEST RAINS. THEREFORE... LOCAL RUNOFF
PROBLEMS WILL LIKELY BE THE END RESULT WHICH SHOULD AFFECT MOSTLY
URBAN AREAS. WE WILL ADD THIS TO THE HAZARDOUS WEATHER OUTLOOK. THE
FINAL LINE OF CONVECTION MAY DROP LOCAL 1 TO 1.5 INCHES IN AN
HOUR... SO SOME URBAN FLASH FLOODING MAY OCCUR IF THIS HAPPENS. THIS
WOULD MOST LIKELY OCCUR LATE WEDNESDAY IN THE WEST... AND LATE
AFTERNOON INTO THE EVENING IN THE EAST.
SEVERE STORMS ARE NOT EXPECTED AT THIS TIME. HOWEVER... GUSTY WINDS
TO 40-45 MPH ARE LIKELY TO OCCUR WITH THE FINAL LINE OF CONVECTION
WEDNESDAY AFTERNOON AND EVENING. MLCAPES IN ADVANCE OF THE FRONT
SHOULD BE HELD DOWN BY THE EXTENSIVE MOISTURE AND CLOUDS/SHOWERS
KEEPING THE SEVERE THREAT LIMITED.
SENSIBLE WEATHER WILL BE FOR RAIN INTO WEDNESDAY MORNING... TAPERING
TO SCATTERED SHOWERS DURING THE DAY. BECOMING BREEZY FROM THE
SOUTHWEST AND TEMPS RISING INTO THE 60S TO LOWER 70S. ANOTHER LINE
OF TWO OF SHOWERS/ISO THUNDERSTORMS SOME WITH GUSTY WINDS WED
AFTERNOON INTO THE EVENING. PARTIAL CLEARING WEDNESDAY NIGHT WITH
LOWS IN THE 40S TO LOWER 50S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 235 AM TUESDAY...
MILD AND DRIER THURSDAY INTO SATURDAY...
BREEZY WEST WINDS CHRISTMAS DAY WITH SKIES BECOMING PARTLY TO MOSTLY
SUNNY. MILD HIGHS IN THE 50S TO LOWER 60S EXPECTED. WINDS SHOULD
DIMINISH DURING THE MID TO LATE AFTERNOON AS THE PRESSURE GRADIENT
WEAKENS AS THE SURFACE HIGH BUILDS IN FROM THE GULF COAST STATES.
MILD TEMPERATURES AND MOSTLY CLEAR SKIES ARE EXPECTED FRIDAY INTO
SATURDAY AS HIGH PRESSURE BUILDS OVER THE SOUTHEAST STATES.
EXPECT LOWS IN THE 30S AND HIGHS IN THE 50S.
MODEL SPREAD STILL INCREASES THROUGH THE WEEKEND...WITH THE EC
CONTINUING MUCH DEEPER WITH THE NEXT MID/UPPER LEVEL
TROUGH...RESULTING IN A STRONGER SURFACE WAVE THAT WOULD BRING YET
ANOTHER WET AND UNSETTLED PERIOD SUNDAY INTO MONDAY. WHEN THE
ENSEMBLES ARE CONSIDERED... A MUCH WEAKER WAVE RESULTS. THEREFORE...
WE WILL SIMPLY INDICATE AN INCREASE IN CLOUDINESS THEN WITH COOLER
TEMPERATURES. THERE MAY BE AN IMPORTANT STORM IF THE EC DOES INDEED
VERIFY LATER SUNDAY INTO EARLY NEXT WEEK.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 715 PM MONDAY...
AVIATION CONDITIONS WILL REMAIN POOR WELL ON THROUGH TONIGHT AND
TUESDAY...WITH PERIODS OF RAIN/DRIZZLE AND A LIGHT NORTHEASTERLY
WIND ALONG WITH THE ALREADY LOW CLOUDS AND LIMITED VSBYS. THERE IS
HIGH CONFIDENCE OF LIFR CONDITIONS THROUGH THE NIGHT AND THERE MAY
ALSO BE SOME VLIFR CONDITIONS RESULTING FROM FOG BETWEEN 06Z AND 12Z.
THERE WILL BE NO CHANGE IN THE AIRMASS OVER NC ON TUESDAY...SO ONLY
MINIMAL IMPROVEMENT IN CONDITIONS IS EXPECTED. CEILINGS MAY LIFT A
LITTLE DURING THE AFTERNOON ALLOWING IFR CONDITIONS TO DEVELOP...BUT
CONFIDENCE IN THIS IS LOW GIVEN HOW LITTLE CONDITIONS CHANGED
EARLIER TODAY. PERIODS OF LIGHT RAIN AND DRIZZLE WILL CONTINUE.
OUTLOOK... AN UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT WILL
APPROACH THE REGION TUESDAY NIGHT AND WEDNESDAY...LEADING TO AN
INCREASED CHANCE OF SHOWERS...ALONG WITH GUSTY WINDS AND A FEW
ISOLATED THUNDERSTORMS (MAINLY OVER EASTERN NC). THUS...AVIATION
CONDITIONS WILL REMAIN POOR THROUGH AT LEAST WEDNESDAY....BEFORE A
COLD FRONT CROSSES THE AREA LATE WEDNESDAY NIGHT AND EARLY THURSDAY.
BEHIND THE FRONT...BLUSTERY WESTERLY WINDS WILL OCCUR CHRISTMAS DAY
WITH GUSTS 30-35KTS POSSIBLE. OTHERWISE VFR CONDITIONS EXPECTED TO
RETURN CHRISTMAS DAY AND PERSIST THROUGH SATURDAY.
&&
.HYDROLOGY...
AS OF 245 AM TUESDAY...
THIS IS THE OUTLOOK FOR AREA RIVERS THROUGH THE UPCOMING STORM.
RAINFALL OVER THE PAST 24 HOURS RANGED FROM AROUND 0.10 IN THE
WESTERN PIEDMONT TO OVER 1 INCH IN THE NORTHEAST PIEDMONT AND
COASTAL PLAIN. THIS WILL PRODUCE ONLY MINOR RISES ON THE
TAR/ROANOKE/NEUSE AND CAPE FEAR RIVERS.
THIS IS THE THIRD SIGNIFICANT RAINFALL EVENT (>0.5 INCHES) OVER THE
AREA SINCE 12/10. RELATIVE SOIL MOISTURE PERCENTAGES IN THE 0-200 CM
COLUMN HAVE BEEN INCREASING...WITH HIGHER WATER PERCENTILES NEARER
THE SURFACE. THEREFORE MORE RUNOFF IS EXPECTED FROM OUR UPCOMING
RAIN EVENT.
CURRENT QUANTITATIVE PRECIPITATION FORECASTS FROM THE MODELS
INCLUDING THE GEFS AND NAEFS ENSEMBLES ARE IN AGREEMENT WITH 1 TO
1.5 INCHES TONIGHT THROUGH EARLY WEDNESDAY... THEN ANOTHER ROUND OF
LOCALY 1+ INCH TOTALS LATER WEDNESDAY AND WEDNESDAY NIGHT WITH THE
COLD FRONT.
STORM TOTAL RAINFALL OF 2 TO LOCALLY 3 INCHES FOR THE ENTIRE EVENT
ENDING WEDNESDAY NIGHT WILL POTENTIALLY CAUSE MINOR FLOODING ON THE
NEUSE RIVER AND TAR RIVER LATE ON CHRISTMAS DAY. HOWEVER... IT WOULD
BE LOW IMPACT WITH THOSE RIVERS LIKELY ONLY REACHING MINOR FLOOD
STAGE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$ SYNOPSIS...VINCENT
NEAR TERM...MWS/WSS
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...BLS
HYDROLOGY...MLM/BADGETT
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1151 PM CST MON DEC 22 2014
.UPDATE...
ISSUED AT 1151 PM CST MON DEC 22 2014
TEMPS IN THE CENTRAL RED RIVER VALLEY HAVE CONTINUE TO HOLD IN THE
34-36 DEGREE RANGE...BUT SOME SNOW IS STARTING TO MIX IN ACROSS
THE FARGO AREA. DRIZZLE REMAINS AT GFK AND BJI...WITH TEMPS STILL
ABOVE FREEZING. WILL CONTINUE TO KEEP A DRIZZLE CHANGING OVER TO
SNOW...WITH FREEZING DRIZZLE IN THE NORTHWEST WHERE TEMPS ARE
LOWER AND THE RAP SHOWS MORE DRYING IN THE -12 TO -18C DENDRITIC
GROWTH ZONE. WILL HOLD HEADLINES AS THEY ARE.
UPDATE ISSUED AT 1005 PM CST MON DEC 22 2014
SPOTTER REPORTS HAVE PRECIP IN DEVILS LAKE STARTING TO CHANGE OVER
TO SNOW. THERE HAVE BEEN SOME REPORTS OF SLICK ROADS IN EASTERN
WALSH AND PEMBINA COUNTIES EVEN THOUGH SFC TEMPS HAVE BEEN MAINLY
ABOVE FREEZING. HOWEVER...RADAR SHOWS PRECIP WILL MOVE FURTHER
WEST OUT OF THOSE AREAS AND INTO THE DEVILS LAKE BASIN. THINK THAT
THERE WILL BE SOME LINGERING FREEZING DRIZZLE CHANGING OVER TO
SNOW IN THE ADVISORY AREA...SO WILL KEEP THE HEADLINE GOING FOR A
BIT LONGER.
FURTHER SOUTH...THE AREAS AROUND FORMAN EASTWARD TO THE PARK
RAPIDS AREA HAVE TRANSITIONED OVER TO SNOW. SHORT TERM MODELS HAVE
THIS BAND HANGING AROUND A BIT LONGER THEN DISSIPATING AFTER
MIDNIGHT. THINK THAT AROUND A HALF AN INCH IS POSSIBLE...SO
ADJUSTED GRIDS OVER TO ALL SNOW. WILL KEEP AN EYE IN CASE THE SNOW
PERSISTS AND DROPS MORE THAN EXPECTED...BUT FOR NOW DO NOT THINK
AN ADVISORY IS NEEDED.
UPDATE ISSUED AT 703 PM CST MON DEC 22 2014
TWEAKED POPS AND PRECIP TYPE A BIT AS A BAND OF RAIN SHOWERS
CONTINUES TO SLOWLY MOVE ACROSS THE CWA. TEMPS HAVE BEEN STEADY OR
RISING IN THE DEVILS LAKE BASIN...BUT WITH SOME SPOTS STILL NEAR
THE FREEZING MARK AND SOME SPOTTY ICE ON ROADS BEING REPORTED BY
ND DOT...WILL KEEP THE ADVISORY GOING FOR RIGHT NOW. MODELS HAVE
TEMPS SLOWLY FALLING OFF THIS EVENING AND A SWITCH OVER TO SNOW
LATER ON OVERNIGHT. WILL KEEP THE HEADLINES AS THEY ARE AND WILL
TAKE A SECOND LOOK AT THE UPDATE IN A FEW HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 330 PM CST MON DEC 22 2014
THE DENSE FOG ACROSS BARNES COUNTY HAS IMPROVED ACCORDING TO
WEB CAMS...AND WILL LET THAT ADVISORY EXPIRE AT 4PM.
ACROSS THE DEVILS LAKE BASIN (WINTER WEATHER ADVISORY UNTIL
12Z)...A FEW SITES STILL AT 32F...WITH OTHERS UP TO 34F. ROADS ARE
MOSTLY WET NOW...BUT IMAGINE SECONDARY ROADS ARE STILL ICY IN
AREAS WHERE TEMPERATURES REMAIN NEAR FREEZING. THERE REMAINS
DRIZZLE/FREEZING DRIZZLE AND AREAS OF DENSE FOG. ANTICIPATE
TEMPERATURES WILL FALL BELOW FREEZING THIS EVENING. FORCING (850MB
WARM AIR ADVECTION) WILL BE INCREASING INTO THIS AREA DURING THE
EVENING AS SEEN ON RADAR IMAGERY WITH STRONGER RETURNS FROM
COOPERSTOWN TO THIEF RIVER FALLS. NOT SURE OF THE PTYPE...WHICH
WILL BE DEPENDENT ON THE AIRMASS ALOFT (MOIST OR DRY?). IF ICE
NUCLEI CAN BE INTRODUCED EXPECT SNOW...IF NOT EXPECT FREEZING
DRIZZLE. LIKELY WILL BE A MIX...WHICH WILL CAUSE WIDESPREAD HAZARDOUS
TRAVEL CONDITIONS (AGAIN). NEXT SHIFTS WILL NEED TO MONITOR PTYPE
AND INCREASE/DECREASE SNOW AMOUNTS ACCORDINGLY (WILL GO AROUND AN
INCH FOR NOW...ANTICIPATE ALL SNOW BY TUESDAY MORNING). THERE HAVE
ALSO BEEN REPORTS OF ICE ACCRETION ON POWER LINES...SO IF MORE
FREEZING DRIZZLE/RAIN OCCURS THIS MAY BE AN ADDITIONAL HAZARD.
THERE WILL BE ANOTHER HEAVIER AREA OF PRECIP ASSOCIATED WITH THE
SFC LOW/INVERTED (SOUTHEAST NORTH DAKOTA) THIS EVENING. THE
RAIN/SNOW LINE LOOKS LIKE IT WILL SET UP JUST WEST OF THE FA...BUT
WILL NEED TO MONITOR.
TO THE EAST...LIKELY WILL BE SNOW MIXING IN WITH DRIZZLE BY TUESDAY
MORNING...JUST NOT SURE WHEN. FORCING IS MUCH WEAKER THAN TO THE
WEST...AND WARM AIR WILL LAST LONGER...AND ONLY EXPECT A DUSTING
OF SNOW (MAYBE UP TO AN INCH OR TWO DEPENDING ON TIMING OF
SWITCH-OVER TO SNOW AND IF/WHERE ANY STRONGER BANDS SET UP ON
TUESDAY).
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 330 PM CST MON DEC 22 2014
FOR TUESDAY NIGHT INTO THURSDAY...TEMPS WILL STAY MILD TUESDAY
NIGHT INTO CHRISTMAS DAY. UPPER RIDGE FLATTENS OUT INTO MORE OF A
ZONAL FLOW AS THE JET CORE PASSES ACROSS SRN CANADA. OTHERWISE...A
WEAK SFC LOW WILL CROSS JUST NORTH OF THE BORDER WITH A TRAILING
TROF CROSSING THE REGION. EXPECTING SOME LIGHT PCPN...MAINLY IN
THE NORTHERN PART OF THE AREA.
THURSDAY NIGHT THROUGH SUNDAY....UPPER TROF DIGGING IN OVER THE
INTERMOUNTAIN WEST...AND A VIGOROUS SHORTWAVE WILL INDUCE
CYCLOGENESIS AND DEVELOP AN AREA OF LOW PRESSURE THAT IS FORECAST TO
TRACK NE INTO IOWA AND WISCONSIN. MODELS PLACE THE BAROCLINIC ZONE
ON THE NW SIDE OF THE LOW ACROSS THE SE PORTION OF THE FORECAST
AREA...WITH ACCOMPANYING PCPN CHANCES. SOME QUESTION ON EXACT
PLACEMENT OF PCPN BAND ATTM...BUT LOOKING AT LEAST SOME MEASURABLE
PCPN ACROSS LAKES COUNTRY BACK TOWARD SE ND. COOLER AIR WILL FILTER
IN BEHIND THE LOW...BRINGING TEMPERATURES BACK DOWN CLOSER TO
SEASONAL NORMS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1151 PM CST MON DEC 22 2014
IFR TO LIFR CONDITIONS CONTINUE AT MOST AREAS...WITH SOME PEAKS OF
MVFR AT TIMES. DRIZZLE AND LIGHT SNOW WILL REDUCE VIS TO AROUND
2-4SM AT TIMES...AND SOME 1SM IS POSSIBLE IN THE HEAVIER BANDS SO
INCLUDED THAT AT MOST TAF SITES TOWARDS MORNING. THINK THAT ANY
SNOW WILL BEGIN TO TAPER OFF MID DAY BUT WINDS WILL PICK UP OUT OF
THE NORTHWEST AT 15 KTS OR SO. CIGS WILL REMAIN IN THE 500-700 FT
RANGE AND THERE SHOULD STILL BE SOME MIST HANGING AROUND AND KEEPING
VIS DOWN IN THE 3-5SM RANGE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR NDZ006-007-
014-015-024-026-028-054.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...HOPKINS
AVIATION...JR
AREA FORECAST DISCUSSION
NWS NORMAN OK
1132 PM CST MON DEC 22 2014
.AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH 24/00Z... BUT THEN MVFR CIGS
ARE EXPECTED TO RETURN TO MANY AREAS AFTER 24/00Z. NORTHWEST WINDS
WILL INCREASE AND BECOME GUSTY AFTER SUNRISE TUESDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 1021 PM CST MON DEC 22 2014/
UPDATE...
INCREASED RAIN CHANCES FOR THE REST OF TONIGHT ACROSS WESTERN
NORTH TEXAS...SOUTH OF A CROWELL TO WICHITA FALLS LINE.
DISCUSSION...
BASED ON LATEST RADAR AND THE KNOX CITY WEST TEXAS MESONET
REPORTING 0.06 INCHES OF RAINFALL IN THE PAST HOUR...INCREASED
RAIN CHANCES IN THE LOCATIONS MENTIONED ABOVE...INCLUDING
THE SEYMOUR...ARCHER CITY...AND KNOX CITY AREAS. LIGHT RAIN
MAY AFFECT PARTS OF FAR SOUTHERN OKLAHOMA...SOUTH OF A WALTERS
TO COALGATE LINE LATER TONIGHT. ANY RAINFALL IS EXPECTED TO
REMAIN LIGHT...GENERALLY 0.01 TO 0.25 INCHES WITH THE HIGHEST
AMOUNTS IN THE LOCATIONS MENTIONED ABOVE.
PRODUCTS HAVE BEEN UPDATED.
MBS
PREV DISCUSSION... /ISSUED 641 PM CST MON DEC 22 2014/
UPDATE...
INCREASED CLOUD COVER TONIGHT AND DELAYED RAIN CHANCES A FEW
HOURS IN WESTERN NORTH TEXAS.
DISCUSSION...
LIGHT RAIN MAY IMPACT LOCATIONS SOUTH OF THE RED RIVER
TONIGHT...MAINLY AFTER MIDNIGHT.
BASED ON LATEST SATELLITE AND HRRR MODEL OUTPUT...INCREASED
CLOUD COVER TONIGHT ACROSS THE AREA...ESPECIALLY SOUTH OF I-40.
LATEST RADARS INDICATED LIGHT PRECIPITATION OVER THE TEXAS HIGH
PLAINS TO OUR WEST...SOME OF WHICH WAS NOT REACHING THE GROUND
DUE TO DRY LOW LEVELS. THINK SOME OF THIS PRECIPITATION WILL REACH
THE GROUND ONCE IT ENTERS WESTERN NORTH TEXAS IN THE NEXT FEW
HOURS...BUT FOR THE MOST PART...MEASURABLE PRECIPITATION...0.01
INCH OF RAINFALL OR GREATER...IS EXPECTED TO OCCUR AFTER MIDNIGHT.
MODEL PROFILES SUPPORT ALL LIQUID AT THE GROUND WITH THIS
PRECIPITATION WITH WET BULB ZERO HEIGHTS ABOVE 1500 FT AGL.
PRODUCTS HAVE BEEN UPDATED.
MBS
PREV DISCUSSION... /ISSUED 539 PM CST MON DEC 22 2014/
AVIATION...
MOSTLY VFR CONDITIONS IN THE 00Z TAFS... FINALLY. AN EXCEPTION MAY
BE OVER FAR SOUTHWEST OKLAHOMA AND WESTERN NORTH TEXAS TUESDAY
MORNING AS SOME MVFR VSBY/CIGS WILL BE POSSIBLE... MOST LIKELY AT
KSPS. THE HIGHEST CHANCES OF PRECIPITATION WILL BE SOUTH OF OUR
TAF SITES.
PREV DISCUSSION... /ISSUED 303 PM CST MON DEC 22 2014/
DISCUSSION...
A FEW WEAK ECHOES ARE SHOWING UP ON AREA RADARS. MEASURABLE
PRECIPITATION IS NOT EXPECTED THROUGH EARLY EVENING...ALTHOUGH A
FEW SMALL PATCHES OF DRIZZLE OR SPRINKLES CANNOT BE RULED OUT.
AN AREA OF MOISTURE AND ISENTROPIC LIFT WILL ACCOMPANY A MID-LEVEL
WAVE ACROSS OUR TEXAS AND FAR SOUTHERN OKLAHOMA COUNTIES
OVERNIGHT AND EARLY TUESDAY. THERE WILL BE A TIGHT GRADIENT OF
RAIN CHANCES ALONG THE NORTHERN EDGE. TEMPERATURES WILL BE WARM
ENOUGH FOR ALL RAIN...EXCEPT POSSIBLY ALONG THE NORTHERN
FRINGE...WHERE A MIX OF RAIN/SNOW MAY OCCUR EARLY TOMORROW
MORNING.
FOR TUESDAY NIGHT INTO EARLY WEDNESDAY...ANOTHER GLOB OF MOISTURE
IS FORECAST TO FOLLOW BEHIND THE DEPARTING STORM SYSTEM. THIS
WILL BRING A CHANCE OF LIGHT SNOW TO NORTHERN OKLAHOMA. MINIMAL
LIFT IS EXPECTED IN THIS PART OF THE STORM SYSTEM...SO ONLY VERY
LIGHT ACCUMULATION IS EXPECTED IN THE NORTHWEST. A MIX OF LIGHT
RAIN AND SNOW MAY EXTEND AS FAR SOUTH AS CENTRAL OKLAHOMA.
STRONG NORTHWEST WINDS ARE EXPECTED TOMORROW...ENHANCED BY COLD
AIR ADVECTION. A WIND ADVISORY MAY BE NEEDED TOMORROW...DEPENDING
ON THE WIND GUIDANCE TRENDS.
CHRISTMAS DAY WILL BE WINDY...WARM...AND DRY. IF CURRENT MODEL
GUIDANCE IS ANYWHERE CLOSE TO CORRECT...A WIND ADVISORY WILL BE
NECESSARY...AND A HIGH WIND WATCH/WARNING MAY NEED TO BE
CONSIDERED. MOST MODELS SHOW 30-50 KT WINDS BETWEEN 850 MB AND THE
LOWEST LAYER ABOVE THE SURFACE.
A COLD FRONT WILL ARRIVE FRIDAY...BRINGING A NOTICEABLE DROP IN
TEMPERATURES. THE WEEKEND IS CURRENTLY BEYOND THE RANGE OF
COHERENT MODEL FORECASTS. THEY DIVERGE QUITE SERIOUSLY AROUND
SATURDAY...SO THE WEEKEND FORECAST IS CURRENTLY A MIX OF GUIDANCE
WITH LOW CONFIDENCE LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 37 48 33 43 / 0 10 20 10
HOBART OK 36 48 31 46 / 10 10 10 0
WICHITA FALLS TX 40 51 34 48 / 20 20 10 0
GAGE OK 32 42 28 45 / 0 20 20 0
PONCA CITY OK 34 46 33 41 / 0 10 20 10
DURANT OK 42 51 36 45 / 20 50 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
99/99/01
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
1021 PM CST MON DEC 22 2014
.UPDATE...
INCREASED RAIN CHANCES FOR THE REST OF TONIGHT ACROSS WESTERN
NORTH TEXAS...SOUTH OF A CROWELL TO WICHITA FALLS LINE.
&&
.DISCUSSION...
BASED ON LATEST RADAR AND THE KNOX CITY WEST TEXAS MESONET
REPORTING 0.06 INCHES OF RAINFALL IN THE PAST HOUR...INCREASED
RAIN CHANCES IN THE LOCATIONS MENTIONED ABOVE...INCLUDING
THE SEYMOUR...ARCHER CITY...AND KNOX CITY AREAS. LIGHT RAIN
MAY AFFECT PARTS OF FAR SOUTHERN OKLAHOMA...SOUTH OF A WALTERS
TO COALGATE LINE LATER TONIGHT. ANY RAINFALL IS EXPECTED TO
REMAIN LIGHT...GENERALLY 0.01 TO 0.25 INCHES WITH THE HIGHEST
AMOUNTS IN THE LOCATIONS MENTIONED ABOVE.
PRODUCTS HAVE BEEN UPDATED.
MBS
&&
.PREV DISCUSSION... /ISSUED 641 PM CST MON DEC 22 2014/
UPDATE...
INCREASED CLOUD COVER TONIGHT AND DELAYED RAIN CHANCES A FEW
HOURS IN WESTERN NORTH TEXAS.
DISCUSSION...
LIGHT RAIN MAY IMPACT LOCATIONS SOUTH OF THE RED RIVER
TONIGHT...MAINLY AFTER MIDNIGHT.
BASED ON LATEST SATELLITE AND HRRR MODEL OUTPUT...INCREASED
CLOUD COVER TONIGHT ACROSS THE AREA...ESPECIALLY SOUTH OF I-40.
LATEST RADARS INDICATED LIGHT PRECIPITATION OVER THE TEXAS HIGH
PLAINS TO OUR WEST...SOME OF WHICH WAS NOT REACHING THE GROUND
DUE TO DRY LOW LEVELS. THINK SOME OF THIS PRECIPITATION WILL REACH
THE GROUND ONCE IT ENTERS WESTERN NORTH TEXAS IN THE NEXT FEW
HOURS...BUT FOR THE MOST PART...MEASURABLE PRECIPITATION...0.01
INCH OF RAINFALL OR GREATER...IS EXPECTED TO OCCUR AFTER MIDNIGHT.
MODEL PROFILES SUPPORT ALL LIQUID AT THE GROUND WITH THIS
PRECIPITATION WITH WET BULB ZERO HEIGHTS ABOVE 1500 FT AGL.
PRODUCTS HAVE BEEN UPDATED.
MBS
PREV DISCUSSION... /ISSUED 539 PM CST MON DEC 22 2014/
AVIATION...
MOSTLY VFR CONDITIONS IN THE 00Z TAFS... FINALLY. AN EXCEPTION MAY
BE OVER FAR SOUTHWEST OKLAHOMA AND WESTERN NORTH TEXAS TUESDAY
MORNING AS SOME MVFR VSBY/CIGS WILL BE POSSIBLE... MOST LIKELY AT
KSPS. THE HIGHEST CHANCES OF PRECIPITATION WILL BE SOUTH OF OUR
TAF SITES.
PREV DISCUSSION... /ISSUED 303 PM CST MON DEC 22 2014/
DISCUSSION...
A FEW WEAK ECHOES ARE SHOWING UP ON AREA RADARS. MEASURABLE
PRECIPITATION IS NOT EXPECTED THROUGH EARLY EVENING...ALTHOUGH A
FEW SMALL PATCHES OF DRIZZLE OR SPRINKLES CANNOT BE RULED OUT.
AN AREA OF MOISTURE AND ISENTROPIC LIFT WILL ACCOMPANY A MID-LEVEL
WAVE ACROSS OUR TEXAS AND FAR SOUTHERN OKLAHOMA COUNTIES
OVERNIGHT AND EARLY TUESDAY. THERE WILL BE A TIGHT GRADIENT OF
RAIN CHANCES ALONG THE NORTHERN EDGE. TEMPERATURES WILL BE WARM
ENOUGH FOR ALL RAIN...EXCEPT POSSIBLY ALONG THE NORTHERN
FRINGE...WHERE A MIX OF RAIN/SNOW MAY OCCUR EARLY TOMORROW
MORNING.
FOR TUESDAY NIGHT INTO EARLY WEDNESDAY...ANOTHER GLOB OF MOISTURE
IS FORECAST TO FOLLOW BEHIND THE DEPARTING STORM SYSTEM. THIS
WILL BRING A CHANCE OF LIGHT SNOW TO NORTHERN OKLAHOMA. MINIMAL
LIFT IS EXPECTED IN THIS PART OF THE STORM SYSTEM...SO ONLY VERY
LIGHT ACCUMULATION IS EXPECTED IN THE NORTHWEST. A MIX OF LIGHT
RAIN AND SNOW MAY EXTEND AS FAR SOUTH AS CENTRAL OKLAHOMA.
STRONG NORTHWEST WINDS ARE EXPECTED TOMORROW...ENHANCED BY COLD
AIR ADVECTION. A WIND ADVISORY MAY BE NEEDED TOMORROW...DEPENDING
ON THE WIND GUIDANCE TRENDS.
CHRISTMAS DAY WILL BE WINDY...WARM...AND DRY. IF CURRENT MODEL
GUIDANCE IS ANYWHERE CLOSE TO CORRECT...A WIND ADVISORY WILL BE
NECESSARY...AND A HIGH WIND WATCH/WARNING MAY NEED TO BE
CONSIDERED. MOST MODELS SHOW 30-50 KT WINDS BETWEEN 850 MB AND THE
LOWEST LAYER ABOVE THE SURFACE.
A COLD FRONT WILL ARRIVE FRIDAY...BRINGING A NOTICEABLE DROP IN
TEMPERATURES. THE WEEKEND IS CURRENTLY BEYOND THE RANGE OF
COHERENT MODEL FORECASTS. THEY DIVERGE QUITE SERIOUSLY AROUND
SATURDAY...SO THE WEEKEND FORECAST IS CURRENTLY A MIX OF GUIDANCE
WITH LOW CONFIDENCE LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 37 48 33 43 / 10 10 20 10
HOBART OK 36 48 31 46 / 10 10 10 0
WICHITA FALLS TX 40 51 34 48 / 20 20 10 0
GAGE OK 32 42 28 45 / 10 20 20 0
PONCA CITY OK 34 46 33 41 / 10 10 20 10
DURANT OK 42 51 36 45 / 20 50 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
17/26
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
215 AM EST TUE DEC 23 2014
.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE NEAR THE DELMARVA PENINSULA WILL
DRIFT SLOWLY TO THE NORTHEAST THIS MORNING. AN INTENSIFYING STORM
SYSTEM WILL TRACK WEST AND NORTH OF PENNSYLVANIA WEDNESDAY
NIGHT...PUSHING A COLD FRONT THROUGH THE STATE ON CHRISTMAS EVE.
ANOTHER LESS POTENT COLD FRONT IS LIKELY TO IMPACT THE REGION BY
NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
PERSISTENT...AND RATHER DEEP SOUTH-SWRLY ISENTROPIC LIFT IN THE
295-305 K THETA LAYER /ATOP A LIGHT EASTERLY FLOW AT THE SFC/ WILL
BE FOCUSED ACRS CENTRAL AND NERN PENN EARLY TODAY.
PERIODS OF LIGHT RAIN...FZRA...AND DRIZZLE WILL OCCUR THROUGH THE
MID MORNING...AND WITH TEMPS TEETERING ON THE 32F MARK THROUGHOUT
MUCH OF THE CENTRAL AND NRN MTNS...WILL MAINTAIN FZRA ADVISORY
THROUGH 09Z. OUTSIDE OF THE ADVISORY AREA...TEMPS WERE MAINLY
IN THE 33-36F RANGE WITH JUST SOME SPOTTY LIGHT RAIN...DRIZZLE AND
PATCHY -FZRA/FZDZ. A FEW LOCATIONS COULD SEE UP TO ONE TENTH OF AN
INCH ICE ACCUM...BUT MOST PLACES WILL SEE LESS. STILL...UNTREATED
ROADS AND WALKWAYS WILL BE TREACHEROUS IN SPOTS.
LATEST RAP MAY BE A FEW HOURS TOO FAST WARMING UP TEMPS
SUFFICIENTLYABOVE THE 32 DEG MARK DURING THE PREDAWN HOURS
TODAY...SO WE MAY OPT TO EXTEND THE ADVISORY THROUGH 13Z.
AFTERWARD...TEMPS CLIMBING INTO THE UPPER 30S TO MID 40S WILL BE
ACCOMPANIED BY DECREASING AREAS OF LIGHT RAIN/SHOWERS OR DRIZZLE
WITH QPF AOB 0.10 OF AN INCH.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
LOOKING AT MAINLY A CLOUDY LATE MORNING AND AFTERNOON TODAY
WITH SOME PATCHY LIGHT RAIN OR DRIZZLE. TEMPERATURES WILL BE
ABOVE NORMAL...BUT MAINLY IN THE 40S...AS THE MAIN LOW IS TOO FAR
WEST FOR CENTRAL PA TO BE IN MUCH OF A SOUTHERLY GRADIENT.
A BETTER CHANCE OF RAIN ARRIVES LATER TONIGHT INTO WED...AS COLD
FRONT MOVES TO THE EAST.
TEMPERATURES WILL CLIMB INTO THE 50S WED AFTERNOON INTO WED
NIGHT...AS STRONGER SOUTHERLY WINDS DEVELOP.
WENT WITH A CHANCE OF THUNDER WED EVENING...GIVEN DEWPOINTS
IN THE UPPER 40S TO LOWER 50S. ALSO FAIRLY STRONG DYNAMICS
AND WIND FIELDS. LIMITING FACTOR FOR SEVERE STORMS WILL BE
TIME OF DAY AND THERMAL RIDGE WELL TO THE EAST OF THE FRONT.
WIND GUST COULD BE IN THE ADVISORY RANGE LATE.
DID NOT BUY INTO THE NAM SOLUTION AT THIS POINT.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
CLOUDS SHOULD BREAK BEHIND THE COLD FRONT ON THU. A FEW SNOW
AND RAIN SHOWERS WILL BE POSSIBLE WITH THE UPPER LEVEL TROUGH.
MUCH OF THE DAY WILL BE DRY. NOT REAL COLD BEHIND THE FRONT.
SW FLOW ON FRIDAY WILL BRING IN MILD AIR.
A FEW MORE SHOWERS LATE FRIDAY INTO SUNDAY...AS THE NEXT COLD
FRONT MOVES ACROSS THE AREA. SHOWERS WILL BE MAINLY IN THE
FORM OF SNOW SHOWERS.
WENT WITH MAINLY DRY CONDITIONS FOR MONDAY. NOT REAL COLD FOR
LATE DEC. THERE COULD BE SOME SNOW SHOWERS LATE MONDAY
NIGHT...BUT WENT WITH A DRY FCST FOR NOW.
WITH SPLIT FLOW...THERE COULD BE SOME CHANCE FOR A SOUTHERN
WAVE TO BRING SOME RAIN OR SNOW SHOWERS TO THE AREA ANYTIME
FROM SUNDAY INTO MID WEEK...BUT AT THIS TIME...LOOKS LIKE
ANYTHING WOULD BE FAST MOVING...AND MAINLY TO THE SOUTH.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
MAIN CONCERN REMAINS THE LIGHT ICING...AND THE TRAPPED LOW LEVEL
STRATOCU GIVEN THE COLD AIR DAMMING AND THE STRONG INVERSION.
LIGHT FREEZING RAIN AND FREEZING DRIZZLE CONTINUES THROUGH ALL
OF CENTRAL PA. THE LOW STRATOCU CONTINUES TO THICKEN WITH ALL TAF
SITES CURRENTLY IFR. THIS STRATOCU IS RELATED TO THE STRONG
INVERSION PRESENT AND AS SUCH MOST SITES SHOULD REMAIN IFR THROUGH
MOIST OF THE PERIOD. THE SOUTHERN TAF SITES...MAINLY LNS AND MDT
COULD SEE SOME RISE IN CIGS TOMORROW AFTERNOON...THOUGH GIVEN THE
WARM MOIST SOUTHWESTERLY FLOW THAT WILL TAKE OVER...CIGS SHOULD
CONTINUES.
TEMPERATURES THROUGH THE CENTRAL AND WESTERN TERMINALS ARE BELOW
FREEZING AND FREEZING PRECIPITATION SHOULD CONTINUE UNTIL AROUND
9Z...WHERE SFC TEMPERATURES SHOULD INCREASE ABOVE FREEZING. THE
LIGHT RAIN/DRIZZLE REMAINS PROBABLE THROUGH TUESDAY...WITH
REDUCING CIGS CONTINUING INTO TOMORROW NIGHT. LLWS IS POSSIBLE AT
JST DUE TO THE DECOUPLE SFC WINDS AND STRONGER WINDS ALOFT.
THE EASTERN TAF SITES SHOULD SEE PRECIPITATION CONTINUE AND THE
LOW CIGS AND VSBYS CONTINUE...WITH THE VSBYS INCREASE DURING THE
DAYTIME TOMORROW. THE CIG REDUCTIONS SHOULD CONTINUE INTO
WEDNESDAY.
OUTLOOK...
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.
SAT...FAIR AND MOSTLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR
PAZ006-010>012-017>019-024>028-033>037-041-042-045-046-049-050-
056-063>065.
&&
$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT/MARTIN
LONG TERM...MARTIN
AVIATION...DEVOIR/CERU
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1137 PM CST MON DEC 22 2014
.UPDATE...
FINAL EVENING UPDATE TO THE FORECAST TO EXPAND ONGOING DENSE FOG
ADVISORY TO INCLUDE AREAS ALONG AND SOUTH OF INTERSTATE 10 AND
WEST OF INTERSTATE 45. VISIBILITIES MAY FLUCTUATE OVER THE
REMAINDER OF THE EVENING HOURS...BUT WILL BE LOW ENOUGH TO PROVIDE
TRAVEL IMPACTS. NO OTHER CHANGES MADE TO ONGOING FORECAST.
HUFFMAN
&&
.PREV DISCUSSION... /ISSUED 1121 PM CST MON DEC 22 2014/
DISCUSSION...
SEE 06Z AVIATION DISCUSSION.
AVIATION...
A MESSY 18-20 HOURS FOR AVIATION INTERESTS IS ON TAP. VSBYS
CONTINUE TO BOUNCE AROUND BUT MANY SITES ARE NOW REPORTING VSBY
BELOW A MILE. HRRR VSBY PROG SHOWS FOG WITH VSBY 1/2 MILE OR LESS
OVER MUCH OF THE SE HALF OF THE AREA INCLUDING KIAH...KHOU...KLBX
AND KGLS. FCST SOUNDINGS SHOWS A BKN015 DEVELOPING BETWEEN 09-12Z
WITH IFR CIGS DEVELOPING ON TUESDAY MORNING. WARM AIR ADVECTION
WILL YIELD SOME LIGHT RAIN OR DRIZZLE ON TUESDAY AND SOME SCT SHRA
ALONG THE FRONT IN THE LATE MORNING INTO AFTN. WINDS WILL INCREASE
RAPIDLY IN THE WAKE OF TOMORROW AFTNS FRONT. EXPECTING VFR CONDS
TO DEVELOP AFTER 03Z. 43
PREV DISCUSSION... /ISSUED 851 PM CST MON DEC 22 2014/
UPDATE...
TWO PRIMARY CONCERNS WITH THE FORECAST UPDATE TONIGHT...FOG /SOME
POTENTIALLY DENSE/ AND TIMING SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH INCOMING FRONT.
SURFACE ANALYSIS AS OF 7 PM PLACED THE COLD FRONT SURGING THROUGH
TEXAS ROUGHLY ALONG A TEXARKANA TO TEMPLE TO OZONA TO CARLSBAD NM
LINE...WITH SURFACE PRESSURE RISES BEHIND THE FRONT ON THE ORDER
OF 2 TO 3 MB OVER THE PAST 3 HOURS. THE COLDER AIR ASSOCIATED WITH
THIS FRONT IS LAGGING BEHIND THIS BOUNDARY A BIT AS 30S AND 40S
OOZE INTO THE TEXAS PANHANDLE AND WESTERN OKLAHOMA ...WITH LITTLE
IMMEDIATE CHANGE IN TEMPERATURES BOTH AHEAD AND BEHIND THE FRONT
IN THE MID TO UPPER 50S TO NEAR 60. BECAUSE OF THIS LAG IN COLDER
AIR...LOW TEMPERATURES IN THE LOW 50S IN CENTRAL TEXAS TO LOW 60S
ALONG THE COAST SHOULD BE ON TRACK. PRESENT TIMING FOR THE COLD
FRONT HAS IT ENTERING THE HOUSTON METRO AREA AROUND 7-9 AM TUESDAY
MORNING.
BOTH INLAND AND COASTAL AREAS ARE AT RISK FOR AT LEAST PATCHY FOG
DEVELOPMENT TONIGHT. GENERALLY CLEAR SKIES AND LIGHT WINDS ALONG
AND SOUTH OF THE HIGHWAY 59 CORRIDOR HAVE SET THE STAGE FOR A
RADIATION FOG EVENT...WITH SEVERAL COASTAL COUNTIES ALREADY
REPORTING REDUCED VISIBILITIES FROM FOG. LATEST RAP/HRRR RUNS
SHOW FOG CONTINUING TO DEVELOP ALONG AND SOUTH OF HIGHWAY 59
OVERNIGHT AND THE PREVIOUS FORECAST UPDATE HANDLES THIS
ANTICIPATED DEVELOPMENT WELL. MAIN QUESTION WILL BE HOW DENSE FOG
WILL ACTUALLY GET /VISIBILITY AT KBYY HAS ALREADY DROPPED BELOW 1
MILE/. WILL CONTINUE TO MONITOR TRENDS FOR POTENTIAL DENSE FOG
ADVISORY LATER TONIGHT. FOR MORE INFORMATION REGARDING THE UPDATE
TO THE MARINE FORECAST...PLEASE SEE THE MARINE DISCUSSION APPENDED
BELOW.
REGARDING RAIN CHANCES...REGIONAL RADAR MOSAIC AS OF 830 PM
SHOWED A COMPLEX OF SHOWERS AND THUNDERSTORMS OVER THE PERMIAN
BASIN DEVELOPING ALONG AND BEHIND THE FRONT. 00Z MODEL DATA
CONTINUES TO TRICKLE IN BUT THE LATEST SOLUTIONS STILL INDICATE
THAT THIS ACTIVITY WILL CONTINUE TO SPREAD EAST TOWARDS SOUTHEAST
TEXAS AS THE ASSOCIATED UPPER LEVEL SYSTEM MOVES ACROSS THE STATE.
RAIN CHANCES WILL BEGIN INCREASING ALONG AND BEHIND THE PASSAGE OF
THE FRONT TONIGHT BUT BEST FORCING FOR RAIN DEVELOPMENT WILL BE
ALONG THE 850 MB FRONT...DELAYING HIGHEST RAIN CHANCES AROUND 3-6
HOURS AFTER FRONTAL PASSAGE. CURRENT FORECAST HANDLES THE
EVOLUTION OF TOMORROW/S RAIN...INCREASING FROM WEST TO EAST DURING
THE DAY AS THE UPPER LEVEL TROUGH PASSES...FAIRLY WELL AND NO
CHANGES WERE MADE TO ONGOING RAIN CHANCES.
HUFFMAN
MARINE...
SURFACE DEW PTS ARE IN THE MID 60S AND WATER TEMPS ARE NEAR 60.
SOME PATCHY SEA FOG DEVELOPED NEAR GALVESTON EARLIER AND FEEL SOME
PATCHY FOG COULD PLAGUE MARINE AREAS OFF AND ON THROUGH TUESDAY
AFTERNOON. NOT SURE HOW WIDESPREAD OR DENSE THE FOG WILL BECOME SO
WILL JUST CALL FOR AREAS OF FOG AND WATCH TRENDS.
A STRONG COLD FRONT SHOULD REACH MATAGORDA BAY BY EARLY
AFTERNOON...GALVESTON BAY AROUND 3 PM AND CROSS THE COASTAL WATERS
BY 6 PM. NORTHWEST WINDS WILL INCREASE RAPIDLY IN THE WAKE OF THE
FRONT AND SPEEDS SHOULD EXCEED 20 KNOTS OVER THE ENTIRE MARINE
AREA BY 00Z WITH OCCASIONAL GUSTS TO GALE FORCE. A SMALL CRAFT
ADVISORY HAS BEEN ISSUED FOR THE MARINE AREAS FOR LATE TUESDAY
AFTERNOON THROUGH TUESDAY NIGHT. THE STRONG OFFSHORE FLOW WILL
DRIVE WATER OUT OF GALVESTON BAY AND FEEL THE UPPER REACHES OF
GALVESTON BAY NEAR MORGANS PT AND MANCHESTER WILL SUFFER FROM LOW
WATER ISSUES. A LOW WATER ADVISORY MAY BE REQUIRED LATE TUESDAY
NIGHT INTO WEDNESDAY. MODERATE TO STRONG WINDS WILL PREVAIL ON
WEDNESDAY BEFORE SPEEDS BEGIN TO DECREASE WEDNESDAY NIGHT. AN
ONSHORE FLOW WILL REDEVELOP THURSDAY AND STRENGTHEN ON FRIDAY.
ANOTHER COLD FRONT WILL CROSS THE MARINE AREA ON SATURDAY NIGHT.
43
PREV DISCUSSION... /ISSUED 619 PM CST MON DEC 22 2014/
DISCUSSION...
SEE 00Z AVIATION DISCUSSION.
AVIATION...
VFR CONDS WILL PREVAIL AT MOST TAF SITES THROUGH 06Z WITH SKY
CONDS TRANSITIONING TO MVFR AHEAD OF A COLD FRONT. KGLS HAD A
BRIEF BOUT WITH LOW CIGS EARLIER IN THE EVENING ASSOCIATED WITH
SOME SEA FOG JUST OFF THE COAST. FCST SOUNDINGS SHOW A REASONABLY
DEEP SATURATE LAYER THAT FEEL SOME LIGHT RAIN WILL BE POSSIBLE
ALONG AND BEHIND TUESDAYS COLD FRONT. CIGS WILL ALSO LOWER TO
IFR/LIFR IN THE WAKE OF THE FRONT. WINDS WILL BECOME STRONG IN THE
WAKE OF THE FRONT AS WELL SO WILL CARRY A GUST GROUP AGAIN. VFR
CONDS EXPECTED TO GRADUALLY RETURN AFTER 00Z WED. 43
PREV DISCUSSION... /ISSUED 535 PM CST MON DEC 22 2014/
UPDATE...
QUICK UPDATE TO GRIDS TO ADD MENTION OF PATCHY FOG FOR COASTAL
AREAS THIS EVENING WHERE AFTERNOON VISIBLE SATELLITE AND
GALVESTON WEBCAMS SHOW A LOW STRATUS DECK/FOG BANK SITTING JUST
OFFSHORE. GUIDANCE DEPICTS WINDS BACKING FROM THE SOUTHWEST TO THE
SOUTHEAST DURING THE OVERNIGHT HOURS AND EXPANDED FOG MENTION TO
INLAND AREAS AS THIS OCCURS...WITH AREAS OF FOG LIKELY DEVELOPING
ALONG THE COAST COURTESY CONTINUED LOW LEVEL MOISTURE ADVECTION.
HUFFMAN
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 53 57 37 53 35 / 20 40 10 10 0
HOUSTON (IAH) 58 61 40 54 36 / 20 40 20 10 0
GALVESTON (GLS) 63 65 45 54 44 / 10 30 10 10 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 9 AM CST TUESDAY FOR THE FOLLOWING
ZONES: AUSTIN...BRAZORIA...COLORADO...FORT BEND...HARRIS...
JACKSON...MATAGORDA...WALLER...WHARTON.
GM...SMALL CRAFT ADVISORY FROM 3 PM TUESDAY TO 6 AM CST WEDNESDAY FOR
THE FOLLOWING ZONES: MATAGORDA BAY...WATERS FROM FREEPORT
TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM.
SMALL CRAFT ADVISORY FROM 6 PM TUESDAY TO 6 AM CST WEDNESDAY FOR
THE FOLLOWING ZONES: GALVESTON BAY...WATERS FROM HIGH
ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...14
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1121 PM CST MON DEC 22 2014
.DISCUSSION...
SEE 06Z AVIATION DISCUSSION.
&&
.AVIATION...
A MESSY 18-20 HOURS FOR AVIATION INTERESTS IS ON TAP. VSBYS
CONTINUE TO BOUNCE AROUND BUT MANY SITES ARE NOW REPORTING VSBY
BELOW A MILE. HRRR VSBY PROG SHOWS FOG WITH VSBY 1/2 MILE OR LESS
OVER MUCH OF THE SE HALF OF THE AREA INCLUDING KIAH...KHOU...KLBX
AND KGLS. FCST SOUNDINGS SHOWS A BKN015 DEVELOPING BETWEEN 09-12Z
WITH IFR CIGS DEVELOPING ON TUESDAY MORNING. WARM AIR ADVECTION
WILL YIELD SOME LIGHT RAIN OR DRIZZLE ON TUESDAY AND SOME SCT SHRA
ALONG THE FRONT IN THE LATE MORNING INTO AFTN. WINDS WILL INCREASE
RAPIDLY IN THE WAKE OF TOMORROW AFTNS FRONT. EXPECTING VFR CONDS
TO DEVELOP AFTER 03Z. 43
&&
.PREV DISCUSSION... /ISSUED 851 PM CST MON DEC 22 2014/
UPDATE...
TWO PRIMARY CONCERNS WITH THE FORECAST UPDATE TONIGHT...FOG /SOME
POTENTIALLY DENSE/ AND TIMING SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH INCOMING FRONT.
SURFACE ANALYSIS AS OF 7 PM PLACED THE COLD FRONT SURGING THROUGH
TEXAS ROUGHLY ALONG A TEXARKANA TO TEMPLE TO OZONA TO CARLSBAD NM
LINE...WITH SURFACE PRESSURE RISES BEHIND THE FRONT ON THE ORDER
OF 2 TO 3 MB OVER THE PAST 3 HOURS. THE COLDER AIR ASSOCIATED WITH
THIS FRONT IS LAGGING BEHIND THIS BOUNDARY A BIT AS 30S AND 40S
OOZE INTO THE TEXAS PANHANDLE AND WESTERN OKLAHOMA ...WITH LITTLE
IMMEDIATE CHANGE IN TEMPERATURES BOTH AHEAD AND BEHIND THE FRONT
IN THE MID TO UPPER 50S TO NEAR 60. BECAUSE OF THIS LAG IN COLDER
AIR...LOW TEMPERATURES IN THE LOW 50S IN CENTRAL TEXAS TO LOW 60S
ALONG THE COAST SHOULD BE ON TRACK. PRESENT TIMING FOR THE COLD
FRONT HAS IT ENTERING THE HOUSTON METRO AREA AROUND 7-9 AM TUESDAY
MORNING.
BOTH INLAND AND COASTAL AREAS ARE AT RISK FOR AT LEAST PATCHY FOG
DEVELOPMENT TONIGHT. GENERALLY CLEAR SKIES AND LIGHT WINDS ALONG
AND SOUTH OF THE HIGHWAY 59 CORRIDOR HAVE SET THE STAGE FOR A
RADIATION FOG EVENT...WITH SEVERAL COASTAL COUNTIES ALREADY
REPORTING REDUCED VISIBILITIES FROM FOG. LATEST RAP/HRRR RUNS
SHOW FOG CONTINUING TO DEVELOP ALONG AND SOUTH OF HIGHWAY 59
OVERNIGHT AND THE PREVIOUS FORECAST UPDATE HANDLES THIS
ANTICIPATED DEVELOPMENT WELL. MAIN QUESTION WILL BE HOW DENSE FOG
WILL ACTUALLY GET /VISIBILITY AT KBYY HAS ALREADY DROPPED BELOW 1
MILE/. WILL CONTINUE TO MONITOR TRENDS FOR POTENTIAL DENSE FOG
ADVISORY LATER TONIGHT. FOR MORE INFORMATION REGARDING THE UPDATE
TO THE MARINE FORECAST...PLEASE SEE THE MARINE DISCUSSION APPENDED
BELOW.
REGARDING RAIN CHANCES...REGIONAL RADAR MOSAIC AS OF 830 PM
SHOWED A COMPLEX OF SHOWERS AND THUNDERSTORMS OVER THE PERMIAN
BASIN DEVELOPING ALONG AND BEHIND THE FRONT. 00Z MODEL DATA
CONTINUES TO TRICKLE IN BUT THE LATEST SOLUTIONS STILL INDICATE
THAT THIS ACTIVITY WILL CONTINUE TO SPREAD EAST TOWARDS SOUTHEAST
TEXAS AS THE ASSOCIATED UPPER LEVEL SYSTEM MOVES ACROSS THE STATE.
RAIN CHANCES WILL BEGIN INCREASING ALONG AND BEHIND THE PASSAGE OF
THE FRONT TONIGHT BUT BEST FORCING FOR RAIN DEVELOPMENT WILL BE
ALONG THE 850 MB FRONT...DELAYING HIGHEST RAIN CHANCES AROUND 3-6
HOURS AFTER FRONTAL PASSAGE. CURRENT FORECAST HANDLES THE
EVOLUTION OF TOMORROW/S RAIN...INCREASING FROM WEST TO EAST DURING
THE DAY AS THE UPPER LEVEL TROUGH PASSES...FAIRLY WELL AND NO
CHANGES WERE MADE TO ONGOING RAIN CHANCES.
HUFFMAN
MARINE...
SURFACE DEW PTS ARE IN THE MID 60S AND WATER TEMPS ARE NEAR 60.
SOME PATCHY SEA FOG DEVELOPED NEAR GALVESTON EARLIER AND FEEL SOME
PATCHY FOG COULD PLAGUE MARINE AREAS OFF AND ON THROUGH TUESDAY
AFTERNOON. NOT SURE HOW WIDESPREAD OR DENSE THE FOG WILL BECOME SO
WILL JUST CALL FOR AREAS OF FOG AND WATCH TRENDS.
A STRONG COLD FRONT SHOULD REACH MATAGORDA BAY BY EARLY
AFTERNOON...GALVESTON BAY AROUND 3 PM AND CROSS THE COASTAL WATERS
BY 6 PM. NORTHWEST WINDS WILL INCREASE RAPIDLY IN THE WAKE OF THE
FRONT AND SPEEDS SHOULD EXCEED 20 KNOTS OVER THE ENTIRE MARINE
AREA BY 00Z WITH OCCASIONAL GUSTS TO GALE FORCE. A SMALL CRAFT
ADVISORY HAS BEEN ISSUED FOR THE MARINE AREAS FOR LATE TUESDAY
AFTERNOON THROUGH TUESDAY NIGHT. THE STRONG OFFSHORE FLOW WILL
DRIVE WATER OUT OF GALVESTON BAY AND FEEL THE UPPER REACHES OF
GALVESTON BAY NEAR MORGANS PT AND MANCHESTER WILL SUFFER FROM LOW
WATER ISSUES. A LOW WATER ADVISORY MAY BE REQUIRED LATE TUESDAY
NIGHT INTO WEDNESDAY. MODERATE TO STRONG WINDS WILL PREVAIL ON
WEDNESDAY BEFORE SPEEDS BEGIN TO DECREASE WEDNESDAY NIGHT. AN
ONSHORE FLOW WILL REDEVELOP THURSDAY AND STRENGTHEN ON FRIDAY.
ANOTHER COLD FRONT WILL CROSS THE MARINE AREA ON SATURDAY NIGHT.
43
PREV DISCUSSION... /ISSUED 619 PM CST MON DEC 22 2014/
DISCUSSION...
SEE 00Z AVIATION DISCUSSION.
AVIATION...
VFR CONDS WILL PREVAIL AT MOST TAF SITES THROUGH 06Z WITH SKY
CONDS TRANSITIONING TO MVFR AHEAD OF A COLD FRONT. KGLS HAD A
BRIEF BOUT WITH LOW CIGS EARLIER IN THE EVENING ASSOCIATED WITH
SOME SEA FOG JUST OFF THE COAST. FCST SOUNDINGS SHOW A REASONABLY
DEEP SATURATE LAYER THAT FEEL SOME LIGHT RAIN WILL BE POSSIBLE
ALONG AND BEHIND TUESDAYS COLD FRONT. CIGS WILL ALSO LOWER TO
IFR/LIFR IN THE WAKE OF THE FRONT. WINDS WILL BECOME STRONG IN THE
WAKE OF THE FRONT AS WELL SO WILL CARRY A GUST GROUP AGAIN. VFR
CONDS EXPECTED TO GRADUALLY RETURN AFTER 00Z WED. 43
PREV DISCUSSION... /ISSUED 535 PM CST MON DEC 22 2014/
UPDATE...
QUICK UPDATE TO GRIDS TO ADD MENTION OF PATCHY FOG FOR COASTAL
AREAS THIS EVENING WHERE AFTERNOON VISIBLE SATELLITE AND
GALVESTON WEBCAMS SHOW A LOW STRATUS DECK/FOG BANK SITTING JUST
OFFSHORE. GUIDANCE DEPICTS WINDS BACKING FROM THE SOUTHWEST TO THE
SOUTHEAST DURING THE OVERNIGHT HOURS AND EXPANDED FOG MENTION TO
INLAND AREAS AS THIS OCCURS...WITH AREAS OF FOG LIKELY DEVELOPING
ALONG THE COAST COURTESY CONTINUED LOW LEVEL MOISTURE ADVECTION.
HUFFMAN
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 53 57 37 53 35 / 20 40 10 10 0
HOUSTON (IAH) 58 61 40 54 36 / 20 40 20 10 0
GALVESTON (GLS) 63 65 45 54 44 / 10 30 10 10 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 9 AM CST TUESDAY FOR THE FOLLOWING
ZONES: BRAZORIA...FORT BEND...JACKSON...MATAGORDA...WHARTON.
GM...SMALL CRAFT ADVISORY FROM 3 PM TUESDAY TO 6 AM CST WEDNESDAY FOR
THE FOLLOWING ZONES: MATAGORDA BAY...WATERS FROM FREEPORT
TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM.
SMALL CRAFT ADVISORY FROM 6 PM TUESDAY TO 6 AM CST WEDNESDAY FOR
THE FOLLOWING ZONES: GALVESTON BAY...WATERS FROM HIGH
ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...14
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1129 PM CST MON DEC 22 2014
.UPDATE...
ISSUED AT 913 PM CST MON DEC 22 2014
CONFIDENCE IS INCREASING THAT SOME HEAVIER SNOWS WILL BE MAKING IT
INTO CLARK COUNTY TONIGHT INTO TOMORROW AFTERNOON...SO HAVE
DECIDED TO ADD THEN INTO THE ADVISORY. 23.01Z RAP SOUNDINGS FROM
CLARK COUNTY SHOW THE THERMAL PROFILE STAYING BELOW FREEZING WITH
THE EXCEPTION OF THE NEAR SURFACE LAYER WHICH ONLY GETS TO 33F OR
SO. AT LEAST FOR THIS EVENING 34F APPEARS TO BE THE CHANGEOVER
LEVEL FROM RAIN TO SNOW...SO WILL USE THAT INTO TONIGHT INTO
TOMORROW. OUTSIDE OF THE ADJUSTMENT TO ADD CLARK TO THE
ADVISORY...WILL BE WAITING ON THE 23.00Z DATA TO COME IN BEFORE
MAKING ANY CHANGES TO THE PREVIOUS FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 245 PM CST MON DEC 22 2014
CHALLENGES CONTINUE WITH THE WINTER STORM THIS EVENING THROUGH
TUESDAY...NAMELY PRECIPITATION TYPE AND SNOW AMOUNTS. 22.12Z MODEL
SUITE MASS FIELDS IN GOOD OVERALL AGREEMENT THROUGH THE EVENT.
HOWEVER...MINOR DIFFERENCES IN THE THERMAL PROFILES...COMPOUNDED
BY THE FACT THAT SOUNDINGS WOBBLE ABOUT THE ZERO DEGREE ISOTHERM
MAKE PRECIPITATION TYPE PARTICULARLY DIFFICULT. ALL SAID...THERE
HAS STILL BEEN A SOUTHERN TREND IN THE TRACK OF THE SURFACE LOW AS
IT BRIEFLY DIPS INTO NORTHERN MO THIS EVENING BEFORE EJECTING
NORTHEASTWARD ACROSS SOUTHERN WI ON TUESDAY. THIS ALLOWS THE
PRIMARY DEFORMATION AXIS TO SET-UP ACROSS THE NORTHWEST THIRD OF
THE FORECAST AREA AND ENHANCES THE CHANCE FOR ACCUMULATING
SNOWFALL PRIMARILY ON TUESDAY.
FOR THIS EVENING...FIRST WAVE OF PRECIPITATION WILL LIFT ACROSS
THE FORECAST AREA. THERMAL PROFILES ARE WARM ENOUGH FOR MOSTLY
RAIN...EXCEPT ACROSS TAYLOR/CLARK COUNTIES WHERE SOME ACCUMULATING
SNOW (LESS THAN AN INCH) IS POSSIBLE. TEMPERATURES WILL CHANGE
VERY LITTLE AND REMAIN IN THE MID TO UPPER 30S.
FOR TONIGHT...LOW-MID LEVEL WARM FRONT WILL SURGE NORTHWARD AS
SURFACE LOW MOVES INTO NORTHEAST IA. A SECONDARY WAVE OF
PRECIPITATION WILL SWEEP ACROSS THE FORECAST AREA FROM SOUTH TO
NORTH ALONG AXIS OF STRONG WARM AIR ADVECTION AND ISENTROPIC LIFT.
IN GENERAL...EXPECT A NARROW CORRIDOR OF A RAIN SNOW MIX NEAR THE
TRACK OF THE SURFACE LOW WITH SNOW TO THE NORTHWEST AND RAIN TO
THE SOUTHEAST. MODELS ARE HINTING AT A 925 TO 850 HPA WARM TONGUE
TO WRAP AROUND THE LOW BY TUESDAY MORNING...BUT ITS IMPACT ON
PRECIPITATION TYPE SHOULD BE FELT MAINLY FOR AREAS THAT WILL
ALREADY BE SEEING RAIN.
ACCUMULATING SNOW IS MAINLY A CONCERN ON TUESDAY WEST OF A LINE
FROM OELWEIN TO LA CROSSE TO WAUSAU. EXPECT RAIN OR A RAIN/SNOW MIX
FARTHER SOUTH AND EAST. WARM AIR THIS EVENING AND A SLOW
TRANSITION TO A COLDER AIR MASS MAY INITIALLY LIMIT SNOWFALL...
BUT MODELS SHOW ALL BUT THE NEAR SURFACE LAYER DROPPING BELOW
FREEZING BY 23.12Z. EXPECT STRONG LIFT FROM 5 TO 8 UBAR/SECOND
ALONG THE -15 C ISOTHERM WITHIN DEFORMATION SNOW AXIS TO GENERATE
SNOWFALL RATES HIGH ENOUGH TO OVERCOME WARM SURFACE TEMPERATURES
AND ACCUMULATE. NEW FORECAST CALLS FOR 1-3 INCHES OF HEAVY WET
SNOW ACROSS PORTIONS OF NORTHEAST IA/SOUTHEAST MN/WESTERN WI WITH
THE HIGHEST AMOUNTS ACROSS ELEVATED TERRAIN. THIS MATCHES FAIRLY
WELL WITH LATEST GFS/NAM COBB OUTPUT AND SREF PLUMES. ACCUMULATING
SNOWFALL WILL BE BEST REALIZED ACROSS GRASSY SURFACES...BUT COULD
STILL SEE SLUSH ACCUMULATIONS ON UNTREATED ROADWAYS MAKING TRAVEL
DIFFICULT...ESPECIALLY DURING THE TUESDAY MORNING COMMUTE. WILL
KEEP CURRENT WINTER WEATHER ADVISORY FOR TAYLOR COUNTY AND MONITOR
ALL OTHER AREAS FOR POSSIBLE EXPANSION. SEE SPS FOR ADDITIONAL
INFORMATION.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 PM CST MON DEC 22 2014
PRECIPITATION WILL DISSIPATE TUESDAY NIGHT WITH ONLY SOME
LINGERING LIGHT SNOW POSSIBLE ON CHRISTMAS EVE DAY. TEMPERATURES
WILL REMAIN IN THE MID 30S. CHRISTMAS DAY WILL BE DRY WITH LITTLE
CHANGE IN TEMPERATURE AS A BROAD SURFACE RIDGE SLIDES ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY.
SNOW CHANCES INCREASE THURSDAY NIGHT THROUGH FRIDAY AS THE NEXT
TROUGH CARVES ITS WAY ACROSS THE WESTERN CONUS. SURFACE LOW TRACK
IS SIMILAR BETWEEN THE 22.12Z GFS/ECMWF/GEM...BUT PRECIPITATION
PLACEMENT DIFFERS BETWEEN THE DRIER ECMWF AND WETTER GFS/GEM. FOR
NOW...WILL FOLLOW SUPERBLEND GUIDANCE AND BROAD BRUSH CHANCE POPS
ACROSS THE FORECAST AREA.
AFTER A COLD FRONT SWEEPS ACROSS THE REGION FRIDAY NIGHT...THE
UPCOMING WEEKEND LOOKS DRY BUT COLDER WITH DAILY HIGH TEMPERATURES
IN THE 20S AND NIGHTTIME LOWS MAINLY IN THE TEENS. THERE IS A
SLIGHT CHANCE FOR SNOW SUNDAY NIGHT INTO MONDAY...BUT GIVEN VAST
MODEL DIFFERENCES...WILL KEEP 20 POPS AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1129 PM CST MON DEC 22 2014
MVFR/IFR CONDITIONS TO PERSIST INTO TUESDAY AS A LOW PRESSURE
SYSTEM LIFTS UP INTO THE REGION. THE MAIN QUESTION WILL BE WITH
PRECIPITATION TYPE AS TEMPERATURES ARE RIGHT AROUND FREEZING. LSE
HAS A HIGHER CHANCE OF BEING MORE RAIN THAN RST...BUT COULD EASILY
CHANGE OVER ON TUESDAY MORNING. LOW CONDITIONS WILL LIKELY HANG ON
THROUGH TUESDAY NIGHT AND POSSIBLY INTO WEDNESDAY. WINDS WILL BE
SHIFTING FROM THE NORTHEAST TO THE NORTHWEST ON TUESDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST TUESDAY FOR WIZ017-029.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...ROGERS
LONG TERM...ROGERS
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS PUEBLO CO
713 AM MST TUE DEC 23 2014
.UPDATE...
ISSUED AT 713 AM MST TUE DEC 23 2014
WINDS CONTINUE TO SLOWLY INCREASE ACROSS THE EASTERN PLAINS WITH
HIGHEST RECORDED GUST IN PAST HOUR OF 46KTS AT SPD. WINDS AND
SNOWFALL LAGGING ACROSS THE PALMER DVD...THOUGH STILL SEEING SOME
ECHOES ACROSS DOUGLAS AND LINCOLN COUNTIES...WHICH COULD POSE
TRAVEL IMPACTS ACROSS PORTIONS OF NORTHEASTERN EL PASO COUNTY AND
THE PALMER DVD. WITH THAT SAID...WILL KEEP WINTER STORM WARNING
ONGOING FOR NORTHERN EL PASO COUNTY FOR NOW...DUE TO POSSIBLE
VISIBILITY REDUCTIONS AND TRAVEL IMPACTS IN LIGHT SNOW AND BLOWING
SNOW...AS ANY ADDITIONAL ACCUMULATIONS ARE EXPECTED TO LIGHT AND
SPOTTY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM MST TUE DEC 23 2014
...STRONG WINDS ACROSS EASTERN COLORADO TODAY...
NO BIG CHANGES TO CURRENT FORECAST WITH STRONG NORTHERLY WINDS
GUSTING TO BETWEEN 50 AND 60 MPH EXPECTED ACROSS MUCH OF EASTERN
COLORADO LATER THIS MORNING AND AFTERNOON...WITH A STRONG SFC-H7
GRADIENT SETTING UP ACROSS THE PLAINS AS UPPER JET CORE ACROSS
WESTERN COLORADO THIS MORNING TRANSLATES EAST THROUGH THE AFTERNOON.
AS OF 3 AM...STARTING TO SEE GUSTY NORTH TO NORTHWEST WINDS OF 20 TO
40 MPH ACROSS NORTHEASTERN COLORADO REACHING AS FAR SOUTH AS LIMON
AND BURLINGTON...WITH BEST 3HRLY SFC PRESSURE RISES OF 2-3 MBS STILL
ACROSS NORTHEASTERN COLORADO AND SOUTHWESTERN NEBRASKA. WITH THAT
SAID...SHOULD SEE STRONG NORTHERLY WINDS HITTING THE PALMER DVD
WITHIN THE NEXT HOUR OR SO...WHICH WILL CONTINUE TO STRENGTHEN AS
SFC PRESSURE GRADIENT TIGHTENS AND CONTINUES SOUTH AND EAST ACROSS
THE REST OF THE SOUTHEAST PLAINS THROUGH THE REST OF THE MORNING.
LATEST HIGHER RESOLUTION HRRR AND RAP MODELS KEEP MOST OF
PRECIPITATION OUT ACROSS THE FAR SE PLAINS AND ALONG THE SOUTHERN
COLORADO AND NEW MEXICO BORDER TODAY...WITH ONE BAND MOVING SOUTH
AND EAST OF BURLINGTON ATTM. HOWEVER...LATEST RADAR AND SATELLITE
INDICATING SOME ENHANCED ECHOES NORTHEAST OF EL PASO AND LINCOLN
COUNTIES...AND WITH THE STRONG NORTHERLY WINDS HITTING THE PALMER
DIVIDE...STILL SHOULD SEE AN ENHANCED PERIOD OF WIND DRIVEN SNOW
ACROSS NORTHERN PORTIONS OF EL PASO COUNTY THROUGH THE MORNING
DRIVE...WITH A FEW INCHES OF ADDITIONAL ACCUMULATIONS POSSIBLE.
THE MAIN ISSUE...HOWEVER...WILL BE EXPECTED POOR VISIBILITIES IN
BLOWING SNOW...WITH TRAVEL ON EAST TO WEST ROADWAYS...ESPECIALLY
HIGHWAYS 24 AND 94 ACROSS NORTHEASTERN EL PASO COUNTY...AS WELL AS I-
25 FROM MONUMENT NORTH TO DENVER...LIKELY BEING VERY HAZARDOUS THIS
MORNING. WITH THAT SAID...HAVE KEPT CURRENT WINTER STORM WARNING IN
PLACE ACROSS NORTHERN EL PASO COUNTY FOR IMPACT OF SNOW AND BLOWING
AND NOT FOR ACTUAL SNOW ACCUMULATIONS. FURTHER SOUTH AND EAST ACROSS
THE PLAINS...COULD SEE SOME TRAVEL ISSUES IN BLOWING DUST AS
WELL...THOUGH WITH MUCH OF THE PLAINS SEEING SOME RECENT
PRECIPITATION...THINK BLOWING DUST WILL BE TOO LOCALIZED FOR ANY
HIGHLIGHTS ATTM.
A RAW AND BLUSTERY DAY EXPECTED ACROSS THE AREA WITH HIGHS ONLY IN
THE 20S AND 30S AS WINDS SLOWLY DIMINISH FROM WEST TO EAST THROUGH
THE AFTERNOON. WITH A COLD AIRMASS IN PLACE AND DECOUPLING WINDS
THROUGH THE EVENING...WILL LIKELY SEE TEMPERATURES TANK ACROSS THE
HIGHER TERRAIN AND VALLEY LOCALES OVERNIGHT...WITH LOWS IN THE
SINGLE DIGITS AND TEENS ACROSS THE EASTERN PLAINS AND MAINLY SINGLE
DIGITS ABOVE AND BELOW ZERO ACROSS THE HIGHER TERRAIN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 331 AM MST TUE DEC 23 2014
AREA WILL BE BETWEEN WEATHER SYSTEMS ON WED AS UPPER RIDGE
MIGRATES WESTWARD THROUGH THE ROCKIES. SHOULD SEE MAX TEMPS BOUNCE
BACK INTO THE 30S AND 40S MOST LOCATIONS...AND FEW SPOTS ALONG AND
JUST WEST OF I-25 MAY APPROACH 50F AS WEAK DOWNSLOPE WINDS
DEVELOP.
NEXT UPPER TROUGH IS ALREADY ONSHORE ACROSS THE PACIFIC
NORTHWEST WEDNESDAY NIGHT...WITH SYSTEM THEN DROPPING INTO THE
GREAT BASIN ON THU. SURFACE PRESSURE FALLS OVER THE EASTERN PLAINS
WED NIGHT WILL BEGIN TO INCREASE DOWNSLOPE WINDS OVER THE EASTERN
MOUNTAINS AND ADJACENT PLAINS...KEEPING LOW TEMPS RATHER MILD
ALONG AND WEST OF I-25. ON THU...UPPER TROUGH BEGINS TO MARCH
EASTWARD OUT OF THE GREAT BASIN TOWARD COLORADO...WITH MODELS
CONTINUING TO CONVERGE ON A DUE EASTWARD TRACK THROUGH THE STATE
LATE THU NIGHT INTO FRI. SNOW WILL REACH THE CONTINENTAL DIVIDE BY
MIDDAY THU...WITH A PERIOD OF HEAVY SNOW POSSIBLE LATE THU/THU
NIGHT. WILL LIKELY NEED A ROUND OF WINTER HIGHLIGHTS FOR HIGHER
DIVIDE ZONES ONCE AGAIN...THOUGH WILL LET TODAY`S HIGHLIGHTS
EXPIRE BEFORE ISSUING ANY NEW ONES. FARTHER EAST...DOWNSLOPE WINDS
WILL INCREASE OVER THE EASTERN MOUNTAINS AND ADJACENT PLAINS
THU...WITH SOME GUSTS IN THE 40-50 KNOT RANGE THU MORNING IN THE
LEE OF THE SOUTHERN SANGRES AS BAND OF STRONGER 700 MB WINDS
MOVES THROUGH. SURFACE COLD FRONT LOOKS TO HANG UP ALONG OR NORTH
OF THE PALMER DIVIDE FOR MUCH OF THE DAY THU...WHICH SHOULD KEEP
MILD AIR IN PLACE OVER MOST OF THE PLAINS...WHERE MAX TEMPS WILL
CLIMB INTO THE 50S...AIDED BY GUSTY WEST WINDS.
COLD FRONT THEN SWEEPS SOUTHWARD THROUGH THE STATE THU NIGHT AS
UPPER TROUGH CROSSES THE STATE. MOST MOUNTAIN AREAS WILL SEE AT
LEAST A QUICK BURST OF ACCUMULATING SNOW THU NIGHT...WITH SOME
LIGHT POST FRONTAL SNOW OVER THE PLAINS AS WELL. NOT EXPECTING BIG
SNOW ACCUMS OVER THE EASTERN MOUNTAINS AND PLAINS...BUT WITH LOW
LEVEL FLOW TURNING BRIEFLY UPSLOPE ALONG I-25 LATE THU
NIGHT...EASTERN MOUNTAINS/RATON MESA/PALMER DIVIDE COULD SEE AT
LEAST A FEW INCHES OF ACCUMULATION BY EARLY FRI MORNING. MAIN
PORTION OF THE UPPER TROUGH MOVES EASTWARD INTO THE PLAINS
FRI...THOUGH SOME WEAKER ENERGY DIVING INTO THE BACKSIDE OF THE
SYSTEM COMBINED WITH PERSISTENT SHALLOW UPSLOPE FLOW WILL KEEP
SOME LIGHT SNOW SHOWERS GOING OVER THE MOUNTAINS AND HIGHER
TERRAIN WEST OF I-25 THROUGH THE DAY. TEMPS FRI WILL RISE LITTLE
AS COLDER AIR POURS SOUTH ACROSS THE REGION...AND SUSPECT MOST
LOCATIONS WILL STAY AT OR BELOW FREEZING FOR MAXES.
A FEW FLURRIES MAY LINGER OVER THE MOUNTAINS EARLY SAT BEFORE
UPPER ENERGY MOVES EAST OF THE STATE...WITH GENERALLY DRY
CONDITIONS FROM SAT AFTERNOON INTO SUN...THOUGH MAX TEMPS WILL
REMAIN BELOW SEASONAL AVERAGES BOTH DAYS. WESTERN TROUGH RELOADS
EARLY NEXT WEEK AS MORE ENERGY DROPS SOUTH TOWARD THE GREAT BASIN
WHILE A RENEWED SURGE OF COLD AIR SPILLS SOUTH OVER THE PLAINS.
MAIN PORTION OF THE TROUGH COULD STAY TOO FAR WEST TO PRODUCE
HEAVY SNOW OVER THE AREA...THOUGH RATHER DEEP UPSLOPE FLOW OVER
THE EASTERN MOUNTAINS AND PLAINS MAY LEAD TO A PROLONGED LIGHT TO
MODERATE SNOW EVENT MON INTO TUE. CURRENT POPS EARLY NEXT WEEK ARE
ON THE LOW SIDE SO FAR...AND WILL LIKELY NEED TO BE INCREASED AS
EVENT COMES INTO BETTER FOCUS LATER THIS WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 331 AM MST TUE DEC 23 2014
MAIN AVIATION CONCERN CONTINUES TO BE STRONG NORTHERLY WINDS
ACROSS THE EASTERN PLAINS THIS MORNING THROUGH THE EARLY
AFTERNOON...WITH GUSTS TO 50KTS POSSIBLE AT COS AND PUB. THERE IS
A LOW PROBABILITY BRIEF IFR CONDITIONS WITH SNOW AND BLOWING AT
BOTH COS AND PUB THIS MORNING...THOUGH WILL ONLY KEEP VCSH AT COS
WITH ACCUMULATING SNOW STAYING NORTH ALONG THE PALMER DVD. WINDS
DIMINISH THROUGH THE AFTERNOON WITH VFR CONDITIONS EXPECTED
THEREAFTER. VFR CONDITIONS EXPECTED AT ALS OVER THE NEXT 24 HOURS
WITH BREEZY NORTH TO NORTHWEST WINDS THROUGH THE AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ095>099.
HIGH WIND WARNING UNTIL 11 AM MST THIS MORNING FOR COZ085-086.
HIGH WIND WARNING UNTIL 2 PM MST THIS AFTERNOON FOR COZ089-093-
094.
WINTER STORM WARNING UNTIL 11 AM MST THIS MORNING FOR COZ084.
&&
$$
UPDATE...MW
SHORT TERM...MW
LONG TERM...PETERSEN
AVIATION...MW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
431 AM MST TUE DEC 23 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM MST TUE DEC 23 2014
...STRONG WINDS ACROSS EASTERN COLORADO TODAY...
NO BIG CHANGES TO CURRENT FORECAST WITH STRONG NORTHERLY WINDS
GUSTING TO BETWEEN 50 AND 60 MPH EXPECTED ACROSS MUCH OF EASTERN
COLORADO LATER THIS MORNING AND AFTERNOON...WITH A STRONG SFC-H7
GRADIENT SETTING UP ACROSS THE PLAINS AS UPPER JET CORE ACROSS
WESTERN COLORADO THIS MORNING TRANSLATES EAST THROUGH THE AFTERNOON.
AS OF 3 AM...STARTING TO SEE GUSTY NORTH TO NORTHWEST WINDS OF 20 TO
40 MPH ACROSS NORTHEASTERN COLORADO REACHING AS FAR SOUTH AS LIMON
AND BURLINGTON...WITH BEST 3HRLY SFC PRESSURE RISES OF 2-3 MBS STILL
ACROSS NORTHEASTERN COLORADO AND SOUTHWESTERN NEBRASKA. WITH THAT
SAID...SHOULD SEE STRONG NORTHERLY WINDS HITTING THE PALMER DVD
WITHIN THE NEXT HOUR OR SO...WHICH WILL CONTINUE TO STRENGTHEN AS
SFC PRESSURE GRADIENT TIGHTENS AND CONTINUES SOUTH AND EAST ACROSS
THE REST OF THE SOUTHEAST PLAINS THROUGH THE REST OF THE MORNING.
LATEST HIGHER RESOLUTION HRRR AND RAP MODELS KEEP MOST OF
PRECIPITATION OUT ACROSS THE FAR SE PLAINS AND ALONG THE SOUTHERN
COLORADO AND NEW MEXICO BORDER TODAY...WITH ONE BAND MOVING SOUTH
AND EAST OF BURLINGTON ATTM. HOWEVER...LATEST RADAR AND SATELLITE
INDICATING SOME ENHANCED ECHOES NORTHEAST OF EL PASO AND LINCOLN
COUNTIES...AND WITH THE STRONG NORTHERLY WINDS HITTING THE PALMER
DIVIDE...STILL SHOULD SEE AN ENHANCED PERIOD OF WIND DRIVEN SNOW
ACROSS NORTHERN PORTIONS OF EL PASO COUNTY THROUGH THE MORNING
DRIVE...WITH A FEW INCHES OF ADDITIONAL ACCUMULATIONS POSSIBLE.
THE MAIN ISSUE...HOWEVER...WILL BE EXPECTED POOR VISIBILITIES IN
BLOWING SNOW...WITH TRAVEL ON EAST TO WEST ROADWAYS...ESPECIALLY
HIGHWAYS 24 AND 94 ACROSS NORTHEASTERN EL PASO COUNTY...AS WELL AS I-
25 FROM MONUMENT NORTH TO DENVER...LIKELY BEING VERY HAZARDOUS THIS
MORNING. WITH THAT SAID...HAVE KEPT CURRENT WINTER STORM WARNING IN
PLACE ACROSS NORTHERN EL PASO COUNTY FOR IMPACT OF SNOW AND BLOWING
AND NOT FOR ACTUAL SNOW ACCUMULATIONS. FURTHER SOUTH AND EAST ACROSS
THE PLAINS...COULD SEE SOME TRAVEL ISSUES IN BLOWING DUST AS
WELL...THOUGH WITH MUCH OF THE PLAINS SEEING SOME RECENT
PRECIPITATION...THINK BLOWING DUST WILL BE TOO LOCALIZED FOR ANY
HIGHLIGHTS ATTM.
A RAW AND BLUSTERY DAY EXPECTED ACROSS THE AREA WITH HIGHS ONLY IN
THE 20S AND 30S AS WINDS SLOWLY DIMINISH FROM WEST TO EAST THROUGH
THE AFTERNOON. WITH A COLD AIRMASS IN PLACE AND DECOUPLING WINDS
THROUGH THE EVENING...WILL LIKELY SEE TEMPERATURES TANK ACROSS THE
HIGHER TERRAIN AND VALLEY LOCALES OVERNIGHT...WITH LOWS IN THE
SINGLE DIGITS AND TEENS ACROSS THE EASTERN PLAINS AND MAINLY SINGLE
DIGITS ABOVE AND BELOW ZERO ACROSS THE HIGHER TERRAIN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 331 AM MST TUE DEC 23 2014
AREA WILL BE BETWEEN WEATHER SYSTEMS ON WED AS UPPER RIDGE
MIGRATES WESTWARD THROUGH THE ROCKIES. SHOULD SEE MAX TEMPS BOUNCE
BACK INTO THE 30S AND 40S MOST LOCATIONS...AND FEW SPOTS ALONG AND
JUST WEST OF I-25 MAY APPROACH 50F AS WEAK DOWNSLOPE WINDS
DEVELOP.
NEXT UPPER TROUGH IS ALREADY ONSHORE ACROSS THE PACIFIC
NORTHWEST WEDNESDAY NIGHT...WITH SYSTEM THEN DROPPING INTO THE
GREAT BASIN ON THU. SURFACE PRESSURE FALLS OVER THE EASTERN PLAINS
WED NIGHT WILL BEGIN TO INCREASE DOWNSLOPE WINDS OVER THE EASTERN
MOUNTAINS AND ADJACENT PLAINS...KEEPING LOW TEMPS RATHER MILD
ALONG AND WEST OF I-25. ON THU...UPPER TROUGH BEGINS TO MARCH
EASTWARD OUT OF THE GREAT BASIN TOWARD COLORADO...WITH MODELS
CONTINUING TO CONVERGE ON A DUE EASTWARD TRACK THROUGH THE STATE
LATE THU NIGHT INTO FRI. SNOW WILL REACH THE CONTINENTAL DIVIDE BY
MIDDAY THU...WITH A PERIOD OF HEAVY SNOW POSSIBLE LATE THU/THU
NIGHT. WILL LIKELY NEED A ROUND OF WINTER HIGHLIGHTS FOR HIGHER
DIVIDE ZONES ONCE AGAIN...THOUGH WILL LET TODAY`S HIGHLIGHTS
EXPIRE BEFORE ISSUING ANY NEW ONES. FARTHER EAST...DOWNSLOPE WINDS
WILL INCREASE OVER THE EASTERN MOUNTAINS AND ADJACENT PLAINS
THU...WITH SOME GUSTS IN THE 40-50 KNOT RANGE THU MORNING IN THE
LEE OF THE SOUTHERN SANGRES AS BAND OF STRONGER 700 MB WINDS
MOVES THROUGH. SURFACE COLD FRONT LOOKS TO HANG UP ALONG OR NORTH
OF THE PALMER DIVIDE FOR MUCH OF THE DAY THU...WHICH SHOULD KEEP
MILD AIR IN PLACE OVER MOST OF THE PLAINS...WHERE MAX TEMPS WILL
CLIMB INTO THE 50S...AIDED BY GUSTY WEST WINDS.
COLD FRONT THEN SWEEPS SOUTHWARD THROUGH THE STATE THU NIGHT AS
UPPER TROUGH CROSSES THE STATE. MOST MOUNTAIN AREAS WILL SEE AT
LEAST A QUICK BURST OF ACCUMULATING SNOW THU NIGHT...WITH SOME
LIGHT POST FRONTAL SNOW OVER THE PLAINS AS WELL. NOT EXPECTING BIG
SNOW ACCUMS OVER THE EASTERN MOUNTAINS AND PLAINS...BUT WITH LOW
LEVEL FLOW TURNING BRIEFLY UPSLOPE ALONG I-25 LATE THU
NIGHT...EASTERN MOUNTAINS/RATON MESA/PALMER DIVIDE COULD SEE AT
LEAST A FEW INCHES OF ACCUMULATION BY EARLY FRI MORNING. MAIN
PORTION OF THE UPPER TROUGH MOVES EASTWARD INTO THE PLAINS
FRI...THOUGH SOME WEAKER ENERGY DIVING INTO THE BACKSIDE OF THE
SYSTEM COMBINED WITH PERSISTENT SHALLOW UPSLOPE FLOW WILL KEEP
SOME LIGHT SNOW SHOWERS GOING OVER THE MOUNTAINS AND HIGHER
TERRAIN WEST OF I-25 THROUGH THE DAY. TEMPS FRI WILL RISE LITTLE
AS COLDER AIR POURS SOUTH ACROSS THE REGION...AND SUSPECT MOST
LOCATIONS WILL STAY AT OR BELOW FREEZING FOR MAXES.
A FEW FLURRIES MAY LINGER OVER THE MOUNTAINS EARLY SAT BEFORE
UPPER ENERGY MOVES EAST OF THE STATE...WITH GENERALLY DRY
CONDITIONS FROM SAT AFTERNOON INTO SUN...THOUGH MAX TEMPS WILL
REMAIN BELOW SEASONAL AVERAGES BOTH DAYS. WESTERN TROUGH RELOADS
EARLY NEXT WEEK AS MORE ENERGY DROPS SOUTH TOWARD THE GREAT BASIN
WHILE A RENEWED SURGE OF COLD AIR SPILLS SOUTH OVER THE PLAINS.
MAIN PORTION OF THE TROUGH COULD STAY TOO FAR WEST TO PRODUCE
HEAVY SNOW OVER THE AREA...THOUGH RATHER DEEP UPSLOPE FLOW OVER
THE EASTERN MOUNTAINS AND PLAINS MAY LEAD TO A PROLONGED LIGHT TO
MODERATE SNOW EVENT MON INTO TUE. CURRENT POPS EARLY NEXT WEEK ARE
ON THE LOW SIDE SO FAR...AND WILL LIKELY NEED TO BE INCREASED AS
EVENT COMES INTO BETTER FOCUS LATER THIS WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 331 AM MST TUE DEC 23 2014
MAIN AVIATION CONCERN CONTINUES TO BE STRONG NORTHERLY WINDS
ACROSS THE EASTERN PLAINS THIS MORNING THROUGH THE EARLY
AFTERNOON...WITH GUSTS TO 50KTS POSSIBLE AT COS AND PUB. THERE IS
A LOW PROBABILITY BRIEF IFR CONDITIONS WITH SNOW AND BLOWING AT
BOTH COS AND PUB THIS MORNING...THOUGH WILL ONLY KEEP VCSH AT COS
WITH ACCUMULATING SNOW STAYING NORTH ALONG THE PALMER DVD. WINDS
DIMINISH THROUGH THE AFTERNOON WITH VFR CONDITIONS EXPECTED
THEREAFTER. VFR CONDITIONS EXPECTED AT ALS OVER THE NEXT 24 HOURS
WITH BREEZY NORTH TO NORTHWEST WINDS THROUGH THE AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ095>099.
HIGH WIND WARNING UNTIL 11 AM MST THIS MORNING FOR COZ085-086.
HIGH WIND WARNING UNTIL 2 PM MST THIS AFTERNOON FOR COZ089-093-
094.
WINTER STORM WARNING UNTIL 11 AM MST THIS MORNING FOR COZ084.
&&
$$
SHORT TERM...MW
LONG TERM...PETERSEN
AVIATION...MW
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
936 AM EST TUE DEC 23 2014
.DISCUSSION...
VISIBILITIES CONTINUE TO IMPROVE ACROSS THE REGION AND HAVE LET
THE DENSE FOG ADVISORY OVER OSCEOLA...INDIAN RIVER AND SOUTHERN
BREVARD COUNTIES EXPIRE. SOME STRATUS CONTINUES ACROSS THE AREA
BUT THIS WILL GRADUALLY BREAK UP AS DAYTIME HEATING CONTINUES AND
SOUTHERLY WINDS JUST OFF THE SURFACE UP TO 15-20 KTS INCREASE
BOUNDARY LAYER MIXING. DRIER/WARMER AIR JUST ABOVE 850MB EVIDENT
IN MORNING SOUNDING AT KMFL WILL ADVECT NORTHWARD INTO THE REGION
AND IMPEDE PRECIP DEVELOPMENT. HOWEVER WILL KEEP A SLIGHT CHANCE
OF SHOWERS NORTH OF ORLANDO WHERE THE HRRR MODEL STILL SHOWS THE
POTENTIAL FOR A FEW SHOWERS TO DEVELOP INTO THE AFT...WHICH
MATCHES UP WELL WITH MAV POPS. HIGH CLOUDS WILL CONTINUE TO PUSH
EASTWARD ACROSS CENTRAL FLORIDA WITH SKIES RANGING FROM PARTLY TO
MOSTLY CLOUDY. ABOVE NORMAL TEMPS EXPECTED TODAY WITH HIGHS IN THE
LOW TO MID 80S.
&&
.AVIATION...CIGS FROM 300-500FT IN STRATUS FROM THE I-4 CORRIDOR
NORTHWARD WILL CONTINUE TO BREAK UP AND LIFT INTO LATE MORNING
WITH VFR CONDS THEN EXPECTED ACROSS THE REGION THROUGH THE REST OF
THE DAY AND EVENING. THE WARM/MOIST SOUTHERLY FLOW WILL BRING LOW
STRATUS BACK TONIGHT BY AROUND MIDNIGHT. MOS SHOWS LIFR AT MOST
TERMINALS...BUT THINK THAT STRENGTHENING WINDS JUST ABOVE THE
SURFACE WILL LIKELY RESULT IN MAINLY IFR CEILINGS. THESE WINDS
WILL REQUIRE MENTION OF LOW LEVEL WIND SHEAR AT MOST SITES BY
MIDNIGHT.
&&
.MARINE...
TODAY-TONIGHT...NO CHANGES PLANNED AS FORECAST LOOKS ON TRACK.
(PREVIOUS DISCUSSION) CONDITIONS FOR SMALL CRAFT WILL DETERIORATE
AS SOUTHERLY WINDS INCREASE IN RESPONSE TO LOW PRESSURE MOVING
FROM THE WESTERN GULF TO MISSISSIPPI DELTA REGION THIS EVENING
WHILE STRENGTHENING. WILL CARRY AN EXERCISE CAUTION STATEMENT FOR
MOST OF THE WATERS AS WINDS INCREASE THIS AFTERNOON. WILL START AN
ADVISORY OFFSHORE NORTH OF SEBASTIAN INLET AROUND MIDNIGHT.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY FOR WINDS FROM 1 AM TO 10 PM EST WEDNESDAY
FOR WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY
LINE 20 TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD
COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE.
&&
$$
WEITLICH/CRISTALDI
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
538 AM CST TUE DEC 23 2014
.SHORT TERM...
TODAY...
331 AM CST
STACKED UPPER/SURFACE LOW PRESSURE WAS OVER IOWA EARLY THIS
MORNING...WITH SURFACE OCCLUSION/WARM FRONT EXTENDING EAST AND
SOUTHEAST ACROSS NORTHERN ILLINOIS INTO WEST CENTRAL INDIANA. AREA
OF STEADIER MODERATE RAIN WAS LIFTING NORTH OF THE IL/WI BORDER...
WITH ONLY SPOTTY SHOWERS OR SOME LINGERING DRIZZLE EXPECTED THIS
MORNING WITHIN SYSTEM DRY SLOT. UPPER LOW IS PROGGED TO WEAKEN AND
SHEAR NORTHEAST ACROSS THE NORTHERN GREAT LAKES THROUGH THIS
AFTERNOON...WITH ITS SURFACE LOW ALSO MOVING NORTHEAST OF THE AREA
AND ALLOWING SOUTHERLY WINDS TO MAINTAIN RELATIVELY MILD WEATHER
ACROSS THE FORECAST AREA WITH TEMPS GENERALLY HOLDING IN THE 40S.
MAY SEE SOME BREAKS IN THE CLOUDS AS SKIES HAVE CLEARED UPSTREAM
ACROSS MISSOURI...THOUGH WILL LIKELY SEE REDEVELOPMENT OF LOWER
CLOUDS IN MOIST LOW LEVEL ENVIRONMENT AND WEAK WEAK TROUGHING
ALOFT.
RATZER
TONIGHT THROUGH WEDNESDAY NIGHT...
323 AM CST
HIGH IMPACT WINTER STORM WITH HEAVY WET SNOW POSSIBLE CHRISTMAS EVE.
GENERALLY SPEAKING...WE ARE IN A MUCH BETTER PLACE WITH RESPECT TO
MODEL AGREEMENT THIS MORNING THAN WE WERE LAST NIGHT OR EVEN 12
HOURS AGO. HOWEVER...THERE REMAIN SOME DIFFERENCES WITH RESPECT TO
THE EXACT TRACK AND SPEED/TIMING OF THE SYSTEM. OTHER FORECAST
BUGABOO IS THE MARGINAL LOW LEVEL THERMAL PROFILES DURING THE HEART
OF THE EVENT.
WHILE THERE ARE STILL DIFFERENCES...ONE THING THE COLLECTION OF
MODEL GUIDANCE HAS NOW COME AROUND TO IS THE IDEA OF AN EXPLOSIVELY
DEEPENING CYCLONE DEVELOPING TRACKING NORTH FROM THE GULF COAST
TODAY TO LOWER MICHIGAN BY CHRISTMAS EVE NIGHT. EVENING UPPER AIR
ANALYSIS DEPICTED 170KT 250MB JET SAMPLED BY 00Z RAOB AT SALT LAKE
CITY...WITH THIS JET DIVING DOWN THE BACK SIDE OF THE LONG WAVE
TROUGH AND PROGGED TO SHARPEN/AMPLIFY SOUTHERN FLANK OF THE TROUGH
OVER THE SOUTHERN PLAINS TODAY. THE UPPER JET EMERGES FROM THE BASE
OF THE TROUGH WEDNESDAY GUIDANCE DEPICTS A RAPIDLY DEEPENING CYCLONE
WITH CIRCULATION PROGGED TO CLOSE OFF ALL THE WAY UP TO 300MB.
THE RAPID DEEPENING AND QUICK MOVEMENT OF THE MID/UPPER LEVEL LOW
WILL LIKELY RESULT IN EXTREMELY IMPRESSIVE LARGE SCALE FORCING WITH
AN IMPRESSIVE TROWAL/DEFORMATION ZONE LIKELY TO DEVELOP ON THE
WESTERN FLANK OF THE CYCLONE. VERY STRONG LOW/MID LEVEL
FRONTOGENESIS WILL OCCUR WITHIN THE TROWAL AND COINCIDENT WITH THE
RAPIDLY STRENGTHENING CYCLONE WILL PROMOTE STRONG VERTICAL
CIRCULATION. GUIDANCE ALSO SUGGESTS WEAKLY STABLE TO UNSTABLE
CONDITIONS ALOFT WITHIN THIS TROWAL WITH NEGATIVE EPV AND STEEP
MID-HIGH LEVEL LAPSE RATES...WHICH GIVEN THE STRONG FRONTOGENESIS
WOULD TEND TO FAVOR A NARROWER BUT INTENSE PRECIPITATION BAND.
GFS/WRF-NAM BOTH INDICATE THE PRESENCE OF SOME WEAK UPRIGHT
INSTABILITY WHICH GIVEN THE FORCING COULD ALLOW FOR UPRIGHT
CONVECTION WITHIN THE DEFO BAND AND POSSIBLY A COUPLE LIGHTNING
STRIKES.
WHILE GUIDANCE IS IN PRETTY GOOD AGREEMENT ON THE ABOVE...THERE ARE
A COUPLE OF KEY AREAS OF LINGERING UNCERTAINTY. FIRST...MODEL
BOUNDARY LAYER THERMAL PROFILES ARE FORECAST TO BE QUITE MARGINAL
FOR SNOW AND EVEN MORE MARGINAL FOR ACCUMULATING SNOW. DESPITE THE
MARGINAL THERMAL PROFILES...AM FAIRLY CONFIDENT THAT DYNAMIC COOLING
WITHIN THE DEFO BAND WILL LIKELY EASILY COOL THE BOUNDARY LAYER
SUFFICIENTLY TO SUPPORT ACCUMULATING SNOW...PARTICULARLY WHERE THE
HEAVIEST PRECIP OCCURS. THE 02/07/13 SYSTEM IS A PRIME EXAMPLE OF A
CASE OF VERY STRONG DYNAMIC COOLING THAT WAS VERY POORLY HANDLED BY
THE MODELS AND RESULTED IN NEARLY 10 INCHES OF SNOW WHERE MODELS
GUIDANCE FORECAST SFC TEMPS IN THE MID TO UPPER 30S.
THE BIGGER UNCERTAINTY AND WHAT IS KEEPING ME FROM JUMPING OUT WITH
A WINTER STORM WATCH AT THIS TIME IS THE TRACK DIFFERENCES IN THE
MODELS. WHILE THEY ARE NOT HUGE AND NOT SURPRISING GIVEN THE RAPIDLY
DEEPENING NATURE OF THE SYSTEM...THEY ARE SUBSTANTIAL ENOUGH TO MAKE
IT TOUGH TO PINPOINT THE PORTION OF OUR CWA MOST AT RISK. GIVEN
COMBINATION OF STRONG FRONTOGENESIS...INSTABILITY...AND MARGINAL
THERMAL PROFILES IT SEEMS LIKELY THE AREAL EXTENT OF HEAVY SNOW
WOULD NOT BE LARGE WITH POTENTIALLY SHARP CUT OFF ON BOTH THE
WESTERN AND EASTERN FLANKS OF THE SNOW BAND...SIMILAR TO WHAT WAS
SEEN IN THE 12/01/2006 SYSTEM WHICH IS ONE OF THE STRONGEST ANALOGS
FOR THIS SYSTEM AND PRODUCED LOCALLY OVER A FOOT OF SNOW.
THE CURRENT SNOWFALL FORECAST MAP WAS CREATED BLENDING VARYING
MODEL TRACK SOLUTIONS TOGETHER WHICH YIELD SNOWFALL AMOUNTS THAT
WILL LIKELY BE TOO LOW WHERE THE HEAVIEST SNOW FALLS AND TOO HIGH
OUTSIDE OF THAT BAND...BUT LIKELY THE BEST COMPROMISE THAT CAN BE
DONE FROM THIS DISTANCE GIVEN WHAT LOOKS TO BE A MESOSCALE HEAVY
SNOW THAT WILL SET UP. WHERE THE HEAVY SNOW BAND SETS UP...THINK IT
IS PRETTY LIKELY THAT VSBYS OF 1/4SM OR LESS WITH HEAVY WET SNOW ARE
LIKELY WITH SNOWFALL RATES >/= 2 INCHES PER HOUR POSSIBLE. THE PEAK
INTENSITY OF THE SNOW LOOKS TO COINCIDE WITH THE DAYTIME HOURS WHEN
MANY PEOPLE WILL LIKELY BE TRAVELING...SO ASSUMING THE BAND SETS UP
AS EXPECTED...IT COULD MAKE TRAVEL EXTREMELY DIFFICULT TOMORROW
AFTERNOON. SOME MODELS ARE AS FAR WEST AS NW IL INTO RFD (PARALLEL
GFS AND WRF-NMM) RANGING TO AS FAR EAST AS NORTHWEST INDIANA (00Z
ECMWF). WOULD TEND TO FAVOR THE MORE WESTERN SOLUTIONS AS RAPIDLY
DEEPENING CYCLONES TYPICALLY TEND TO END UP FARTHER WEST THAN
PROGGED WHICH COULD FAVOR CHICAGO AREA OR POINTS JUST WEST FOR THE
HEAVY SNOW THREAT. BUT WITH A STILL RELATIVELY LARGE SPREAD IN TRACK
SOLUTIONS WOULD BE DIFFICULT TO PIN POINT A SPECIFIC AREA FOR A
WINTER STORM WATCH WHEN IN REALITY THE HEAVY (6"+) SNOW AMOUNTS
COULD BE CONFINED TO <25MI WIDE SWATH. AFTER COORDINATION
INTERNALLY...WITH NEIGHBORING WFOS...AND WPC HAVE OPTED TO JUST HIT
THE THREAT HARD IN UPDATED SPS AND HOPEFULLY MORNING MODEL RUNS WILL
NARROW DOWN THE THREAT AREA ENOUGH TO ALLOW HEADLINES TO BE ISSUED
BY MIDDAY.
IZZI
&&
.LONG TERM...
331 AM CST
THURSDAY THROUGH MONDAY...
DEEPENING LOW PRESSURE FROM CHRISTMAS EVE STORM LIFTS QUICKLY AWAY
FROM THE REGION THURSDAY MORNING...WITH BUILDING UPPER RIDGE ALOFT
BETWEEN DEPARTING LOW AND UPSTREAM TROUGH OVER THE WESTERN CONUS.
GUIDANCE IN REASONABLE AGREEMENT IN SENDING A LEAD SHORT WAVE
NORTHEAST TOWARD THE UPPER MIDWEST ON FRIDAY...WITH SURFACE LOW
PRESSURE TRACKING TO OUR NORTHWEST FROM IOWA TO THE UPPER PENINSULA
OF MICHIGAN. SOUTHERLY FLOW DEVELOPS IN ADVANCE OF THIS SYSTEM AND
ITS TRAILING COLD FRONT...WITH TEMPERATURES SURGING BACK INTO THE
40S FRIDAY. MODEL QPF IS HIGHEST FARTHER SOUTH AHEAD OF THE COLD
FRONT ACROSS THE LOWER OHIO VALLEY...THOUGH IT DOES LOOK LIKE A
POTENTIAL FOR SOME LIGHT RAIN OR RAIN/SNOW MIX TO DEVELOP ACROSS THE
AREA FRIDAY NIGHT...WITH SOME LINGERING LIGHT SNOW OR SNOW SHOWERS
LINGERING ACROSS THE SOUTHEASTERN CWA SATURDAY AS COLDER AIR SPREADS
IN ON BLUSTERY WEST-NORTHWEST WINDS.
STRONG HIGH PRESSURE THEN BUILDS SOUTHEAST ACROSS THE PLAINS AND
UPPER MIDWEST INTO SUNDAY...THOUGH ECMWF MAINTAINS A LITTLE LIGHT
PRECIPITATION ALONG THE RETREATING BAROCLINIC ZONE TO OUR SOUTHEAST
AND HAVE KEPT SOME LOW POPS FOR LIGHT SNOW SATURDAY NIGHT AND SUNDAY
FOR SOUTH AND EAST OF THE CHICAGO AREA. THE REMNANT WESTERN CONUS
UPPER TROUGH THEN MOVES EAST ACORSS THE SOUTHERN PLAINS AND LOWER
MISSISSIPPI/OHIO VALLEYS SUNDAY NIGHT. DRY NORTHERLY FLOW
AROUND THE UPPER MIDWEST HIGH...WITH GENERALLY DRY AND SEASONABLY
COLD WEATHER SUNDAY INTO MONDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* CIG TRENDS TODAY...WITH VFR CONDITIONS POSSIBLE BY LATE
MORNING/EARLY AFTERNOON.
* STRONG STORM SYSTEM TO IMPACT THE REGION ON
WEDNESDAY...POTENTIAL FOR SOME HEAVY WET SNOW AND VERY LOW
CONDITIONS...ESPECIALLY IN THE AFTERNOON.
KJB
//DISCUSSION...UPDATED 12Z...
WINDS WILL PICK UP A BIT OUT OF THE SOUTH-SOUTHWEST BY MID MORNING
AS A FRONTAL BOUNDARY LIFTS NORTHWARD ACROSS THE AREA. IT ALSO
APPEARS THAT CIGS WILL BE ON AN IMPROVING TREND TODAY...WITH VFR
CONDITIONS LOOKING TO BE A GOOD POSSIBLY BY LATE MORNING. THE NEXT
MAIN WEATHER CONCERN WILL BE ON WEDNESDAY AS A STRENGTHENING STORM
SYSTEM LIFTS UP THE OHIO VALLEY AND INTO LOWER MICHIGAN. THIS
STORM SYSTEM LOOKS TO RESULT IN ANOTHER PERIOD OF PRECIPITATION
ACROSS THE AREA...AND A DECENT POTENTIAL FOR THIS TO CHANGE OVER
TO SOME HEAVY WET SNOW. ALTHOUGH CONFIDENCE IS INCREASING THAT
THIS PRECIPITATION WILL CHANGE OVER TO SNOW...UNCERTAINTY REMAINS
RATHER HIGH AS TO THE EXACT TIMING THIS MAY OCCUR ON WED. IF THE
HEAVY SNOW DOES MATERIALIZE...PERIODS OF IFR TO VLIFR VIS AND
CIGS WOULD BE LIKELY AT TIMES DURING THE DAY.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM ON CIG TRENDS.
* LOW TO MEDIUM ON POTENTIAL FOR SNOW ON WEDNESDAY...BUT LOW ON
ONSET TIMING AND CHANGE OVER FROM RA TO SN.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...SNOW ENDING IN THE EVENING. IFR OR LOWER
IMPROVING.
THURSDAY...CHANCE OF MVFR CIGS...MAINLY EARLY.
FRIDAY...CHANCE OF MVFR CIGS. STRONG SOUTH WINDS POSSIBLE.
SATURDAY AND SUNDAY...CHANCE OF MVFR CIGS.
MONDAY...MAINLY VFR.
KJB
&&
.MARINE...
217 AM CST
AN INITIAL AREA OF LOW PRESSURE ACROSS SOUTHERN IOWA THIS
MORNING...WILL SHIFT A WARM FRONTAL BOUNDARY FROM NORTH TO SOUTH UP
THE LAKE DURING THE DAY. THEREFORE...SOME STIFF EASTERLIES WILL
SHIFT SOUTHERLY BY LATE IN THE DAY. FOLLOWING THIS...IT STILL
APPEARS LIKELY THAT A SECOND RATHER SIGNIFICANT STORM SYSTEM WILL
RAPIDLY DEVELOP NEAR THE GULF COAST AND RACE NORTHWARD...WHILE
DEEPENING CONSIDERABLE...ACROSS THE OHIO VALLEY AND OVER THE CENTRAL
GREAT LAKES REGION BY CHRISTMAS EVE. DUE TO THE STRENGTH OF THIS
LOW...IT APPEARS THAT A PERIOD OF GALE FORCE WINDS WILL BE A DECENT
POSSIBLY...ESPECIALLY OVER THE OPEN WATERS CHRISTMAS EVE.
THEREFORE...I HAVE ISSUED A GALE WATCH FOR THE OPEN WATERS OF LAKE
MICHIGAN. DUE TO THE FAST MOVEMENT OF THE STORM...WINDS LOOK TO DROP
BELOW GALE FORCE BY CHRISTMAS DAY. STRONG WINDS AND HIGH WAVES ARE
ALSO EXPECTED OVER THE NEAR SHORE WATERS. HOWEVER...I HAVE OPTED
TO LEAVE THE GALE WATCH OUT OF THE NEAR SHORE WATERS AT THIS
TIME...THOUGH SOME GALES CANT BE RULED OUT.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM TUESDAY.
GALE WATCH...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM WEDNESDAY TO 3 AM
THURSDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...6 PM WEDNESDAY TO 6 AM THURSDAY.
&&
$$
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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
535 AM CST Tue Dec 23 2014
.SHORT TERM...(Today)
ISSUED AT 506 AM CST TUE DEC 23 2014
Initial shortwave associated with a closed low at 500 mb early this
morning was tracking across north central Illinois. Backedge of the
rain has shifted into our east and northeast counties...soon to exit
our area for this morning. Mid level dry slot seen on satellite data
tracking east into parts of west central Illinois. Most of the short
term models shift the lower clouds to our northeast this morning
allowing some breaks to develop. HRRR and RUC soundings showing
the low level moisture slowly lifting with time this morning, but
that shouldn`t last long as mid and high level clouds start to stream
northeast into our area ahead of the second shortwave that will bring
another round of rain, then snow to our area starting tonight. Air
mass in the wake of the weak frontal passage today not very cold at
all, in fact, 925-850 mb temperature forecasts suggests highs this
afternoon will range from the upper 40s north to the middle 50s
southeast.
&&
.LONG TERM...(Tonight through Monday)
ISSUED AT 506 AM CST TUE DEC 23 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 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 530 AM CST TUE DEC 23 2014
MVFR and local IFR cigs will become VFR this morning with PIA on
the edge of some wrap around moisture from the departing storm
system. Forecast soundings showing despite the loss of the low
level moisture, quite a bit of mid and high level cloud cover
will affect the TAF sites this morning into the afternoon hours
before more MVFR cigs approach the area for late this evening and
into the overnight hours ahead of the next storm system. As the
next storm system approaches from the south tonight, rain will
overspread the area from south to north after 04z with CMI and
DEC the first to see the rain followed by SPI and BMI aftr 06z
and then PIA during the early morning hours. Once the rain begins
it appears the cigs will quickly drop to MVFR and then eventually
IFR once again, but at this time will hold off bringing cigs and
or vsbys down too much in this forecast period as it appears the
IFR and LIFR cigs will be during the day Wed. Surface winds will
be out of the southwest today at 10 to 15 kts, and the gradually
turn into a light northwest to north direction tonight at 4 to
9 kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Smith
LONG TERM...07
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS JACKSON KY
1020 AM EST TUE DEC 23 2014
.UPDATE...
ISSUED AT 1020 AM EST TUE DEC 23 2014
SATELLITE THIS MORNING SHOWING A FEW BREAKS IN THE CLOUDS
PARTICULARLY ACROSS SE PORTIONS OF THE CWA. ALSO SEEING A FEW SHOWERS
MOVING ALONG THE WESTERN CWA BORDER. CLOUDS AND SHOWERS EXPECTED TO
INCREASE THROUGH THE DAY TODAY. EVEN SLIGHT CHANCE OF A THUNDERSTORM
ONCE WE MOVE INTO THE AFTERNOON HOURS FROM SW TO NE. NO MAJOR CHANGES
MADE THIS UPDATE. DID FRESHEN UP THE GRID WITH LATEST OBS AND TRENDS.
UPDATE ISSUED AT 638 AM EST TUE DEC 23 2014
NO UPDATE PLANNED THIS MORNING. SCATTERED SHOWERS CONTINUE TO SLIDE
NORTH ACROSS THE WESTERN HALF OF THE AREA. LATEST HRRR IS FLUCTUATING
A BIT NOW ON THE EXPECTED ARRIVAL OF MORE WIDESPREAD RAIN LATER THIS
AFTERNOON...BUT STILL BRINGS MOST OF IT INTO THE AREA BY EARLY
EVENING. WON`T MAKE ANY CHANGES AT THIS TIME AND SEE IF THE NEXT FEW
RUNS LOCK ONTO BETTER TIMING.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 315 AM EST TUE DEC 23 2014
A CUT OFF LOW CONTINUES TO SPIN ACROSS THE CENTRAL PLAINS THIS
MORNING WITH BROAD SOUTHWEST FLOW ACROSS THE OHIO RIVER VALLEY. LOW
LEVEL FLOW REMAINS SOUTHEAST ACROSS EASTERN KENTUCKY. A LULL IN
PRECIPITATION IS OCCURRING PRESENTLY ACROSS THE AREA AS THE LATEST
WAVE RESPONSIBLE FOR SOME RAIN EARLIER TONIGHT HAS EXITED TO THE
NORTH. HOWEVER...MORE SHOWERS ARE SPREADING NORTH OUT OF CENTRAL
TENNESSEE AND WILL PROVIDE SOME RAIN INTO SOUTHERN KENTUCKY OVER THE
NEXT FEW HOURS. THE BEST CHANCES FOR RAIN THROUGH MIDDAY WILL REMAIN
ACROSS THE WESTERN HALF OF THE AREA.
ANOTHER WILL EMERGE FROM THE UPPER LEVEL TROUGH AND PUSH NORTH ACROSS
THE TENNESSEE VALLEY THIS AFTERNOON AND EVENING...BRINGING WIDESPREAD
SHOWERS BACK TO THE AREA. THE SHOWALTER INDEX REMAINS NEGATIVE
THROUGH THE NEXT 24 TO 36 HOURS ACROSS MOST OF THE AREA. THUS...ANY
ENHANCED AREAS OF LIFT WILL PROVIDE THE POSSIBILITY OF SOME THUNDER.
THE THUNDER THREAT SHOULD REMAIN ALL ELEVATED LATER TODAY AND
TONIGHT. GIVEN THE TREMENDOUS LIFT ARRIVING LATE IN THE DAY AND THE
WIDESPREAD COVERAGE DEPICTED IN THE HRRR...HAVE OPTED FOR
CATEGORICAL POPS LATE IN THE DAY INTO TONIGHT. AS THIS INITIAL WAVE
EXITS TO THE NORTH...WE MAY SEE ANOTHER LULL THROUGH A PORTION OF
TONIGHT. HOWEVER...ANOTHER STRONG WAVE WILL PUSH NORTH LATE TONIGHT
WITH AN AREA OF LOW PRESSURE TRACKING NORTHWARD ACROSS CENTRAL
KENTUCKY. THIS WILL BRING ANOTHER ROUND OF WIDESPREAD SHOWERS AND
EMBEDDED THUNDERSTORMS TO THE AREA.
AS THE LOW PRESSURE SYSTEM STRENGTHENS AND HEADS INTO MICHIGAN ON
WEDNESDAY...IT WILL SEND A STRONG COLD FRONT TO THE EAST ACROSS
KENTUCKY. AGAIN...GOOD CONVERGENCE AND LIFT ALONG THE FRONT SHOULD
PROVIDE ANOTHER PERIOD OF WIDESPREAD SHOWERS. THIS FRONT WILL ALSO
PRODUCE THE BEST CHANCE OF THUNDER THROUGH THE FORECAST PERIOD AS IT
CROSSES THE AREA IN THE AFTERNOON AND EVENING HOURS. THIS TIME
AROUND...WE MAY BE ABLE TO GENERATE ENOUGH SURFACE BASED INSTABILITY
TO POSSIBLY MIX DOWN SOME OF THE STRONGER WINDS AS THE SHOWERS ALONG
THE FRONT PUSH EAST. THIS COULD YIELD WINDS 45+ KNOTS. EVEN WITHOUT
THE INSTABILITY...SYNOPTIC WINDS WILL TURN QUITE GUSTY JUST BEHIND
THE FRONT WITH WIND GUSTS REACHING AS HIGH AS 40 MPH AT TIMES. AS THE
FRONT PUSHES EAST...WE SHOULD FINALLY SEE PRECIPITATION COME TO AN
END FROM WEST TO EAST THROUGH THE EVENING HOURS WEDNESDAY AS A DRY
SLOT OVERSPREADS THE AREA.
TEMPERATURES WILL REMAIN ON THE MILD SIDE THROUGH WEDNESDAY WITH
HIGHS WELL INTO THE 60S BOTH DAYS AND LOWS TONIGHT ONLY IN THE 50S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 425 AM EST TUE DEC 23 2014
THE PERIOD WILL BEGIN WITH A DEEP CLOSED LOW AND ASSOCIATED SFC
SYSTEM CENTERED OVER THE GREAT LAKES REGION WITH A TROUGH EXTENDING
SOUTH INTO THE MS VALLEY. RIDGING IS EXPECTED TO BE OFF THE SOUTHEAST
US COAST WITH RIDGING ALSO OVER NORTHERN MEXICO AND INTO THE SOUTHERN
AND CENTRAL ROCKIES. A TROUGH IS EXPECTED TO BE WORKING ACROSS THE
NORTHWESTERN CONUS AT THAT POINT AS WELL. FROM THU INTO THE START OF
THE WEEKEND...THE DEEP LOW INITIALLY OVER THE GREAT LAKES WILL TRACK
NORTH ACROSS ONTARIO AND QUEBEC AND INTO THE MARITIMES WITH THE
TRAILING TROUGH AXIS MOVING ACROSS THE AREA EARLY IN THE PERIOD ON
WED NIGHT INTO EARLY ON THU. RIDGING SHOULD THEN WORK ACROSS THE
EASTERN CONUS FROM LATER ON CHRISTMAS DAY INTO FRIDAY. MEANWHILE THE
COLD FRONT TRAILING FROM THE SYSTEM MOVING THROUGH THE GREAT LAKES
INITIALLY SHOULD HAVE EXITED INTO WV OR SHOULD EXIT INTO WV VERY
EARLY IN THE PERIOD. A DRY SLOT SHOULD WORK ACROSS THE AREA EARLY IN
THE PERIOD PER RECENT MODEL CONSENSUS FOLLOWED BY SOMEWHAT DEEPER
WRAPAROUND MOISTURE LATER ON WED NIGHT. SFC HIGH PRESSURE WILL BUILD
IN BEHIND THE DEPARTING LOW PRESSURE SYSTEM FOR THU NIGHT INTO FRI
NIGHT.
FROM WED INTO FRIDAY...A TROUGH WILL HAVE DEVELOPED AND WORKED ACROSS
THE WESTERN CONUS AND SHOULD BE MOVING INTO THE PLAINS BY THE START
OF THE WEEKEND. AT THAT POINT...THE MOST RECENT GFS AND ECMWF RUNS
BEGIN TO DIFFER IN TIMING OF INDIVIDUAL WAVES BUT THERE IS A GENERAL
THEME OF LOWERING HEIGHTS ACROSS THE EASTERN SEABOARD AND SOUTHEAST
FROM THE WEEKEND INTO EARLY NEXT WEEK WITH A TROUGH OVER THE WESTERN
INTO THE CENTRAL CONUS BECOMING INCREASINGLY BROAD WITH TIME. THE
GENERAL CONSENSUS IS FOR A COLD FRONT TO ENTER THE LOWER OH AND
APPALACHIAN REGION FROM FRI NIGHT INTO SATURDAY AND THEN SHIFT SOUTH
OF THE REGION AS EARLY AS SAT AFTERNOON OR EVENING PER THE GFS AND
AS LATE SAT NIGHT INTO SUN PER THE ECMWF.
THE UPPER LEVEL TROUGH AND WRAPAROUND MOISTURE SHOULD LEAD TO SHOWER
AND DRIZZLE CHANCES FROM WED NIGHT INTO MIDDAY ON THURSDAY. SOME SNOW
COULD MIX IN AS WELL. LOCATIONS BELOW 2000 OR 2500 FEET ELEVATION
SHOULD REMAIN ABOVE FREEZING ON WED NIGHT. BEHIND THE DEPARTING
SYSTEM AND IN ADVANCE OF A SFC HIGH...THE LOW LEVEL FLOW WILL BECOME
TOO SOUTHWEST FOR IDEAL UPSLOPE FLOW BUT LOW LEVEL LAPSE RATES WILL
SUPPORT THE CHANCES FOR SHOWERS AND OR DRIZZLE. IN ADDITION...MODEL
FORECAST SOUNDINGS INDICATE THAT ICE CRYSTALS COULD BE LOST AT TIMES
LEADING TO LIGHT PRECIP POSSIBLY FALLING FROM CLOUDS WHERE ICE IS NOT
PRESENT...LEADING TO JUST RAIN OR DRIZZLE AT TIMES. THERE MAY BE
TIMES WHERE ICE IS PRESENT SO SOME FLURRIES OR LIGHT SNOW WOULD ALSO
BE POSSIBLE...BUT CHANCES FOR THIS ARE BEST ON THE RIDGES. A BIT OF
FREEZING DRIZZLE ALSO CANNOT BE RULED OUT LATE WED NIGHT INTO EARLY
ON THURSDAY FOR ELEVATIONS ABOVE 2000 OR 2500 FEET ELEVATION. THE
PRESSURE GRADIENT WILL REMAIN RATHER STEEP WELL INTO WED NIGHT...SO
WIND GUSTS AS HIGH AS 35 TO 40 MPH WILL BE POSSIBLE. A SLIGHTLY
STRONGER GUST CANNOT BE RULED OUT ABOVE 2500 FEET. AS THE MOISTURE
BECOMES INCREASINGLY SHALLOW AS CHRISTMAS DAY PROGRESSES ANY LINGERING
DRIZZLE SHOULD DISSIPATE WITH SOME PARTIAL CLEARING...ESPECIALLY IN
WESTERN SECTIONS. HIGH PRESSURE SHOULD LEAD TO DRY WEATHER FOR THU
EVENING INTO MOST OF FRIDAY NIGHT.
BOTH OF SCENARIOS FROM THE 0Z GFS AND 0Z ECMWF RUNS POINT TOWARD
MAINLY RAIN...POSSIBLY MIXING WITH OR CHANGING TO SNOW ON SAT INTO
SAT NIGHT. CURRENT MODEL RUNS HAVE A WAVE DEVELOPING ON SAT INTO SAT
NIGHT ALONG THE BOUNDARY THAT WILL HAVE PASSED TO OUR SOUTH WITH AN
INVERTED TROUGH EXTENDING TO ITS NORTH IN RESPONSE TO A SHORTWAVE
WORKING FROM HE SOUTHERN ROCKIES ACROSS THE SOUTHERN PLAINS AND INTO
THE SOUTHEASTERN CONUS FROM SAT NIGHT INTO SUN NIGHT. THE MODELS
TRACK THE SFC WAVE ACROSS THE SOUTHEASTERN STATES DURING THAT TIME. IF
DEEP ENOUGH MOISTURE LINGERS AS THIS SYSTEM DEPARTS ON SUN NIGHT INTO
EARLY ON MONDAY...SOME SNOW MIGHT MIX IN.
OVERALL..TEMPERATURES THROUGH THE PERIOD WILL REMAIN NEAR NORMAL TO
ABOVE NORMAL AS THE CORE OF THE COLDER AIRMASSES REMAINS MAINLY
BOTTLED UP OVER CANADA AND NEARER TO THE US/CANADIAN BORDER. THE
BIGGEST DEPARTURES SHOULD OCCUR FROM FRI INTO SATURDAY. SOME MODEL
GUIDANCE SUGGESTS THAT AT LEAST A GLANCING BLOW OF COLDER AIR MAY
AFFECT THE AREA AROUND THE MIDDLE OF NEXT WEEK...BUT THERE HAS BEEN
PLENTY OF MODEL DIFFERENCES FROM RUN TO RUN AND MODEL TO MODEL DURING
THAT TIME PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 638 AM EST TUE DEC 23 2014
A MIX OF VFR/MVFR CONDITIONS WILL BE SEEN OVER THE NEXT 12 TO 24
HOURS AS A NUMBER OF WEAK DISTURBANCES PUSH NORTH AHEAD OF AN UPPER
LEVEL TROUGH ADVANCING FROM THE WEST. SCATTERED SHOWERS WILL REMAIN
POSSIBLE THROUGH THE DAY TODAY...WITH THE BEST CHANCES FOR MORE
WIDESPREAD RAIN COMING LATER THIS EVENING. A DAMP NIGHT IS ON TAP FOR
TONIGHT AS MORE RAIN CONTINUES TO SPREAD NORTHWARD ACROSS THE AREA.
THIS WILL KEEP CIGS LOCKED AT MVFR LEVELS PERHAPS GETTING CLOSE TO
IFR. SOME REDUCED VISIBILITIES WILL ALSO BE LIKELY WITH THE HEAVIER
RAIN SHOWERS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...KAS
LONG TERM...JP
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
638 AM EST TUE DEC 23 2014
.UPDATE...
ISSUED AT 638 AM EST TUE DEC 23 2014
NO UPDATE PLANNED THIS MORNING. SCATTERED SHOWERS CONTINUE TO SLIDE
NORTH ACROSS THE WESTERN HALF OF THE AREA. LATEST HRRR IS FLUCTUATING
A BIT NOW ON THE EXPECTED ARRIVAL OF MORE WIDESPREAD RAIN LATER THIS
AFTERNOON...BUT STILL BRINGS MOST OF IT INTO THE AREA BY EARLY
EVENING. WON`T MAKE ANY CHANGES AT THIS TIME AND SEE IF THE NEXT FEW
RUNS LOCK ONTO BETTER TIMING.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 315 AM EST TUE DEC 23 2014
A CUT OFF LOW CONTINUES TO SPIN ACROSS THE CENTRAL PLAINS THIS
MORNING WITH BROAD SOUTHWEST FLOW ACROSS THE OHIO RIVER VALLEY. LOW
LEVEL FLOW REMAINS SOUTHEAST ACROSS EASTERN KENTUCKY. A LULL IN
PRECIPITATION IS OCCURRING PRESENTLY ACROSS THE AREA AS THE LATEST
WAVE RESPONSIBLE FOR SOME RAIN EARLIER TONIGHT HAS EXITED TO THE
NORTH. HOWEVER...MORE SHOWERS ARE SPREADING NORTH OUT OF CENTRAL
TENNESSEE AND WILL PROVIDE SOME RAIN INTO SOUTHERN KENTUCKY OVER THE
NEXT FEW HOURS. THE BEST CHANCES FOR RAIN THROUGH MIDDAY WILL REMAIN
ACROSS THE WESTERN HALF OF THE AREA.
ANOTHER WILL EMERGE FROM THE UPPER LEVEL TROUGH AND PUSH NORTH ACROSS
THE TENNESSEE VALLEY THIS AFTERNOON AND EVENING...BRINGING WIDESPREAD
SHOWERS BACK TO THE AREA. THE SHOWALTER INDEX REMAINS NEGATIVE
THROUGH THE NEXT 24 TO 36 HOURS ACROSS MOST OF THE AREA. THUS...ANY
ENHANCED AREAS OF LIFT WILL PROVIDE THE POSSIBILITY OF SOME THUNDER.
THE THUNDER THREAT SHOULD REMAIN ALL ELEVATED LATER TODAY AND
TONIGHT. GIVEN THE TREMENDOUS LIFT ARRIVING LATE IN THE DAY AND THE
WIDESPREAD COVERAGE DEPICTED IN THE HRRR...HAVE OPTED FOR
CATEGORICAL POPS LATE IN THE DAY INTO TONIGHT. AS THIS INITIAL WAVE
EXITS TO THE NORTH...WE MAY SEE ANOTHER LULL THROUGH A PORTION OF
TONIGHT. HOWEVER...ANOTHER STRONG WAVE WILL PUSH NORTH LATE TONIGHT
WITH AN AREA OF LOW PRESSURE TRACKING NORTHWARD ACROSS CENTRAL
KENTUCKY. THIS WILL BRING ANOTHER ROUND OF WIDESPREAD SHOWERS AND
EMBEDDED THUNDERSTORMS TO THE AREA.
AS THE LOW PRESSURE SYSTEM STRENGTHENS AND HEADS INTO MICHIGAN ON
WEDNESDAY...IT WILL SEND A STRONG COLD FRONT TO THE EAST ACROSS
KENTUCKY. AGAIN...GOOD CONVERGENCE AND LIFT ALONG THE FRONT SHOULD
PROVIDE ANOTHER PERIOD OF WIDESPREAD SHOWERS. THIS FRONT WILL ALSO
PRODUCE THE BEST CHANCE OF THUNDER THROUGH THE FORECAST PERIOD AS IT
CROSSES THE AREA IN THE AFTERNOON AND EVENING HOURS. THIS TIME
AROUND...WE MAY BE ABLE TO GENERATE ENOUGH SURFACE BASED INSTABILITY
TO POSSIBLY MIX DOWN SOME OF THE STRONGER WINDS AS THE SHOWERS ALONG
THE FRONT PUSH EAST. THIS COULD YIELD WINDS 45+ KNOTS. EVEN WITHOUT
THE INSTABILITY...SYNOPTIC WINDS WILL TURN QUITE GUSTY JUST BEHIND
THE FRONT WITH WIND GUSTS REACHING AS HIGH AS 40 MPH AT TIMES. AS THE
FRONT PUSHES EAST...WE SHOULD FINALLY SEE PRECIPITATION COME TO AN
END FROM WEST TO EAST THROUGH THE EVENING HOURS WEDNESDAY AS A DRY
SLOT OVERSPREADS THE AREA.
TEMPERATURES WILL REMAIN ON THE MILD SIDE THROUGH WEDNESDAY WITH
HIGHS WELL INTO THE 60S BOTH DAYS AND LOWS TONIGHT ONLY IN THE 50S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 425 AM EST TUE DEC 23 2014
THE PERIOD WILL BEGIN WITH A DEEP CLOSED LOW AND ASSOCIATED SFC
SYSTEM CENTERED OVER THE GREAT LAKES REGION WITH A TROUGH EXTENDING
SOUTH INTO THE MS VALLEY. RIDGING IS EXPECTED TO BE OFF THE SOUTHEAST
US COAST WITH RIDGING ALSO OVER NORTHERN MEXICO AND INTO THE SOUTHERN
AND CENTRAL ROCKIES. A TROUGH IS EXPECTED TO BE WORKING ACROSS THE
NORTHWESTERN CONUS AT THAT POINT AS WELL. FROM THU INTO THE START OF
THE WEEKEND...THE DEEP LOW INITIALLY OVER THE GREAT LAKES WILL TRACK
NORTH ACROSS ONTARIO AND QUEBEC AND INTO THE MARITIMES WITH THE
TRAILING TROUGH AXIS MOVING ACROSS THE AREA EARLY IN THE PERIOD ON
WED NIGHT INTO EARLY ON THU. RIDGING SHOULD THEN WORK ACROSS THE
EASTERN CONUS FROM LATER ON CHRISTMAS DAY INTO FRIDAY. MEANWHILE THE
COLD FRONT TRAILING FROM THE SYSTEM MOVING THROUGH THE GREAT LAKES
INITIALLY SHOULD HAVE EXITED INTO WV OR SHOULD EXIT INTO WV VERY
EARLY IN THE PERIOD. A DRY SLOT SHOULD WORK ACROSS THE AREA EARLY IN
THE PERIOD PER RECENT MODEL CONSENSUS FOLLOWED BY SOMEWHAT DEEPER
WRAPAROUND MOISTURE LATER ON WED NIGHT. SFC HIGH PRESSURE WILL BUILD
IN BEHIND THE DEPARTING LOW PRESSURE SYSTEM FOR THU NIGHT INTO FRI
NIGHT.
FROM WED INTO FRIDAY...A TROUGH WILL HAVE DEVELOPED AND WORKED ACROSS
THE WESTERN CONUS AND SHOULD BE MOVING INTO THE PLAINS BY THE START
OF THE WEEKEND. AT THAT POINT...THE MOST RECENT GFS AND ECMWF RUNS
BEGIN TO DIFFER IN TIMING OF INDIVIDUAL WAVES BUT THERE IS A GENERAL
THEME OF LOWERING HEIGHTS ACROSS THE EASTERN SEABOARD AND SOUTHEAST
FROM THE WEEKEND INTO EARLY NEXT WEEK WITH A TROUGH OVER THE WESTERN
INTO THE CENTRAL CONUS BECOMING INCREASINGLY BROAD WITH TIME. THE
GENERAL CONSENSUS IS FOR A COLD FRONT TO ENTER THE LOWER OH AND
APPALACHIAN REGION FROM FRI NIGHT INTO SATURDAY AND THEN SHIFT SOUTH
OF THE REGION AS EARLY AS SAT AFTERNOON OR EVENING PER THE GFS AND
AS LATE SAT NIGHT INTO SUN PER THE ECMWF.
THE UPPER LEVEL TROUGH AND WRAPAROUND MOISTURE SHOULD LEAD TO SHOWER
AND DRIZZLE CHANCES FROM WED NIGHT INTO MIDDAY ON THURSDAY. SOME SNOW
COULD MIX IN AS WELL. LOCATIONS BELOW 2000 OR 2500 FEET ELEVATION
SHOULD REMAIN ABOVE FREEZING ON WED NIGHT. BEHIND THE DEPARTING
SYSTEM AND IN ADVANCE OF A SFC HIGH...THE LOW LEVEL FLOW WILL BECOME
TOO SOUTHWEST FOR IDEAL UPSLOPE FLOW BUT LOW LEVEL LAPSE RATES WILL
SUPPORT THE CHANCES FOR SHOWERS AND OR DRIZZLE. IN ADDITION...MODEL
FORECAST SOUNDINGS INDICATE THAT ICE CRYSTALS COULD BE LOST AT TIMES
LEADING TO LIGHT PRECIP POSSIBLY FALLING FROM CLOUDS WHERE ICE IS NOT
PRESENT...LEADING TO JUST RAIN OR DRIZZLE AT TIMES. THERE MAY BE
TIMES WHERE ICE IS PRESENT SO SOME FLURRIES OR LIGHT SNOW WOULD ALSO
BE POSSIBLE...BUT CHANCES FOR THIS ARE BEST ON THE RIDGES. A BIT OF
FREEZING DRIZZLE ALSO CANNOT BE RULED OUT LATE WED NIGHT INTO EARLY
ON THURSDAY FOR ELEVATIONS ABOVE 2000 OR 2500 FEET ELEVATION. THE
PRESSURE GRADIENT WILL REMAIN RATHER STEEP WELL INTO WED NIGHT...SO
WIND GUSTS AS HIGH AS 35 TO 40 MPH WILL BE POSSIBLE. A SLIGHTLY
STRONGER GUST CANNOT BE RULED OUT ABOVE 2500 FEET. AS THE MOISTURE
BECOMES INCREASINGLY SHALLOW AS CHRISTMAS DAY PROGRESSES ANY LINGERING
DRIZZLE SHOULD DISSIPATE WITH SOME PARTIAL CLEARING...ESPECIALLY IN
WESTERN SECTIONS. HIGH PRESSURE SHOULD LEAD TO DRY WEATHER FOR THU
EVENING INTO MOST OF FRIDAY NIGHT.
BOTH OF SCENARIOS FROM THE 0Z GFS AND 0Z ECMWF RUNS POINT TOWARD
MAINLY RAIN...POSSIBLY MIXING WITH OR CHANGING TO SNOW ON SAT INTO
SAT NIGHT. CURRENT MODEL RUNS HAVE A WAVE DEVELOPING ON SAT INTO SAT
NIGHT ALONG THE BOUNDARY THAT WILL HAVE PASSED TO OUR SOUTH WITH AN
INVERTED TROUGH EXTENDING TO ITS NORTH IN RESPONSE TO A SHORTWAVE
WORKING FROM HE SOUTHERN ROCKIES ACROSS THE SOUTHERN PLAINS AND INTO
THE SOUTHEASTERN CONUS FROM SAT NIGHT INTO SUN NIGHT. THE MODELS
TRACK THE SFC WAVE ACROSS THE SOUTHEASTERN STATES DURING THAT TIME. IF
DEEP ENOUGH MOISTURE LINGERS AS THIS SYSTEM DEPARTS ON SUN NIGHT INTO
EARLY ON MONDAY...SOME SNOW MIGHT MIX IN.
OVERALL..TEMPERATURES THROUGH THE PERIOD WILL REMAIN NEAR NORMAL TO
ABOVE NORMAL AS THE CORE OF THE COLDER AIRMASSES REMAINS MAINLY
BOTTLED UP OVER CANADA AND NEARER TO THE US/CANADIAN BORDER. THE
BIGGEST DEPARTURES SHOULD OCCUR FROM FRI INTO SATURDAY. SOME MODEL
GUIDANCE SUGGESTS THAT AT LEAST A GLANCING BLOW OF COLDER AIR MAY
AFFECT THE AREA AROUND THE MIDDLE OF NEXT WEEK...BUT THERE HAS BEEN
PLENTY OF MODEL DIFFERENCES FROM RUN TO RUN AND MODEL TO MODEL DURING
THAT TIME PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 638 AM EST TUE DEC 23 2014
A MIX OF VFR/MVFR CONDITIONS WILL BE SEEN OVER THE NEXT 12 TO 24
HOURS AS A NUMBER OF WEAK DISTURBANCES PUSH NORTH AHEAD OF AN UPPER
LEVEL TROUGH ADVANCING FROM THE WEST. SCATTERED SHOWERS WILL REMAIN
POSSIBLE THROUGH THE DAY TODAY...WITH THE BEST CHANCES FOR MORE
WIDESPREAD RAIN COMING LATER THIS EVENING. A DAMP NIGHT IS ON TAP FOR
TONIGHT AS MORE RAIN CONTINUES TO SPREAD NORTHWARD ACROSS THE AREA.
THIS WILL KEEP CIGS LOCKED AT MVFR LEVELS PERHAPS GETTING CLOSE TO
IFR. SOME REDUCED VISIBILITIES WILL ALSO BE LIKELY WITH THE HEAVIER
RAIN SHOWERS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM...JP
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
644 AM EST TUE DEC 23 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EST TUE DEC 23 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO
CENTERED NEAR OMAHA BTWN BIG UPR RDG ALONG THE W COAST AND ANOTHER
OFF THE E COAST. THE WRN GREAT LKS ARE UNDER THE SW FLOW ALOFT E OF
THIS FEATURE. WV IMAGERY SHOWS A RATHER IMPRESSIVE SHRTWV LIFTING TO
THE NE THRU IL E OF THE CLOSED LO WITH AREA OF COOLING CLD TOP TEMPS
CORRESPONDING TO WHETHER THE MODELS ARE SHOWING SOME IMPRESSIVE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV. EVEN THOUGH THE
SHARPER DYNAMIC FORCING IS STILL WELL S OF UPR MI EARLY THIS MRNG...
SOME LIGHT SN INVADED THE AREA LAST EVNG UNDER SOME DEEP ISENTROPIC
ASCENT/DEEP SATURATION SHOWN ON THE 00Z GRB RAOB /00Z PWAT WAS 0.57
INCH OR 225 PCT OF NORMAL AT GRB/WELL TO THE NE OF THE CLOSED LO.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS MAINLY ON POPS/QPF/PTYPE
ASSOCIATED WITH THE STRONG SHRTWV OVER IL THAT WL LIFTING QUICKLY
NNEWD TODAY AND GOING HEADLINES.
TODAY...IL SHRTWV IS FCST TO LIFT NEWD TO NEAR MENOMINEE/ESCANABA BY
18Z AND THEN TO FAR ERN LAKE SUP BY 00Z TUE. SHARP DPVA/DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE IS FCST TO IMPACT THE CWA
THRU THE DAY BEFORE BEGINNING TO SUBSIDE LATE. THE SHARPER FORCING
IS FCST TO GLANCE THE WRN ZNS. MODELS HAVE SHOWN GOOD CONTINUITY IN
FCSTG AN AXIS OF HIER H7 SPECIFIC HUMIDITY ARND 3 G/KG AND AN AXIS
OF SHARPER H85-7 FGEN THAT IS FCST TO ROTATE NWWD AND BE ORIENTED IN
A LINE OVER THE CENTRAL CWA BY 18Z ON THE CYC SIDE OF THE SHRTWV
TRACK. THIS DEFORMATION BAND SHOULD SERVE AS THE FOCUS FOR THE
HEAVIEST PCPN. H7 SPECIFIC HUMIDITY AT 3 G/KG SUPPORTS ABOUT 6
INCHES OF SN IN THE 12HR PERIOD OF EXPECTED FORCING...IN GOOD
AGREEMENT WITH HPC FCST STRIPE OF 4 TO 6 INCHES OF SN OVER THE
CENTRAL CWA. RATHER HI AND THIN DGZ BTWN 10-13K FT WL LIMIT SN/WATER
RATIOS...SO THE SN WL BE WET AND HEAVY. EVENTUAL DRY SLOTTING TO THE
E OF THIS DEFORMATION ZN BY 18Z OVER THE SE AND EXPANDING NEWD THRU
THE AFTN WL LIMIT SN TOTALS IN THAT AREA AS THE PCPN. THERE ARE ALSO
PTYPE CONCERNS...ESPECIALLY OVER THE E HALF. THE 00Z NAM FCST SDNGS
SHOW A BIT OF AN ELEVATED WARM LYR WITH WARM NOSE/H9 TEMP ABOVE 0C
CENTERED ARND H9 MOVING AS FAR W AS IRON MOUNTAIN AND THEN
ENVELOPING MUCH OF THE NCNTRL COUNTIES. GIVEN THE SW-NE FCST TRACK
OF THE SHRTWV WL FOLLOW THE SOMEWHAT COLDER 00Z CNDN MODEL FCST
TEMPS...WHICH IS SUPPORTED BY THE 00Z GFS AND LATEST RAPID REFRESH
MODELS. THESE MODELS HINT THE PCPN WL MIX WITH OR CHANGE TO RA E OF
LINE FM MARQUETTE TO IRON MOUTNAIN...CONSISTENT WITH THE AXIS OF THE
DEFORMATION ZN AND SHARPER UVV ON ITS CYC SIDE THAT WL TEND TO
OFFSET THE WAA. THE ONLY EXCEPTION WL BE NEAR LK SUP FM THE KEWEENAW
TO MARQUETTE...WHERE HIER SFC TEMPS NEAR THE WARMING INFLUENCE OF LK
SUP WL SUPPORT AT LEAST A MIX WITH SOME RA. FOR LOCATIONS AWAY FM
FAR SRN MENOMINEE COUNTY AND THE IMMEDIATE LK MI/BAY OF GREEN BAY
SHORES...THE MIX WITH OR CHANGE TO RA/DZ WL NOT OCCUR UNTIL AFTER
THE HEAVIER DEFORMATION ZN SN BAND HAS LIFTED TO THE NW. ADDED A
MENTION OF SOME FOG LATER TODAY OVER THE E WITH HI LLVL RH/MELTING
SN WITH MAX TEMPS NEAR 35 UNDER SOME MID LVL DRYING. OVERALL... THE
INHERITED HEADLINES WITH ADVYS FOR THE ENTIRE CWA STILL LOOK OKAY.
ALTHOUGH THE SHARPER FORCING WL MISS THE FAR WRN CWA...STILL LOOKING
FOR 2 TO 4 INCHES OF WET SNOW IN THAT AREA...ENUF TO JUSTIFY THE
ADVY.
TNGT...IN THE WAKE OF DEPARTING SHRTWV...DEEP LYR QVECTOR DVGC IS
FCST TO DOMINATE THE CWA...WITH EXPANDING MID LVL DRYING. EXPECT THE
HIER POPS IN THE EVNG OVER THE W UNDER LINGERING DEEPER MSTR. WITH
THE SHALLOW MOIST LYR BLO THE DGZ...NOT OUT OF THE QUESTION THERE
COULD BE SOME FREEZING DZ...ESPECIALLY OVER THE HIER TERRAIN OF THE
NCENTRAL AND W WHERE NNE FLOW WL UPSLOPE AND TEMPS WL BE AOB 32. BUT
RELATIVELY UNSTABLE NATURE OF THE LLVL LAPSE RATES WL LIMIT THIS
POTENTIAL. MIN TEMPS WL BE WELL ABOVE NORMAL FOR THE SEASON...NO
LOWER THAN THE UPR 20S OVER THE INTERIOR W. MAINTAINED MENTION OF
FOG THRU THE NGT OVER THE E HALF WHERE TEMPS ARE LIKELY TO REMAIN
ABOVE 32 WITH MOIST AIR OVER MELTING SN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 503 AM EST TUE DEC 23 2014
FOLLOWED THE ECMWF/GEM FOR THE TRACK OF THE LOW PRESSURE SYSTEM
LIFTING JUST EAST OF LOWER MICHIGAN WEDNESDAY AFTN INTO CHIRSTMAS
EVE. GIVEN THE STRENGTH OF THE JET STREAK UP TO 180 KTS OVER THE
INTERMOUNTAIN WEST AND COULPLE OF STRONGER SHORTWAVES DIGGING INTO
THE BASE OF CNTRL PLAINS TROUGH...THINK GFS AND PARALLEL GFS MODELS
ARE TOO QUICK TO BRING THE SHORTWAVE NORTH TO MICHIGAN ON WEDNESDAY
WHICH ALSO PUSHES THE LOW FARTHER TO THE WEST COMPARED TO OTHER
MODELS. 00Z NAM WAS ON THE SLOWER SIDE BUT WOULD TEND TO BUY THAT
IDEA GIVEN HOW FAR SOUTH THIS WAVE WILL INITIALLY DIG INTO TX BEFORE
LIFTING BACK TO THE NORTH. ESSENTIALLY ECMWF/GEM AND NAM IDEAS KEEP
BULK OF DEFORMATION PRECIP JUST NORTHWEST OF SFC-H85 LOWS...MAINLY
IN THE FORM OF SNOW...JUST EAST OF THE CWA. FOR THE POPS/QPF/SNOW
FOLLOWED CLOSELY TO THE WPC GUIDANCE WHICH RESULTED IN CATEGORICAL
POPS FOR LUCE COUNTY LATE WEDNESDAY AFTN INTO CHRISTMAS EVE. HIGH
POPS TAPER QUICKLY TO THE WEST MORE INTO THE CENTRAL CWA.
FOR MOST OF THE CWA ON WEDNESDAY...MAIN CONCERN WILL BE LINGERING
LGT SNOW IN WAKE OF THE SYSTEM MOVING THROUGH TODAY. SOUNDINGS STILL
SHOWING DZ/FZDZ SIGNAL AS WELL WITH MOISTURE UP TO AROUND -7C AND
DRYING ABOVE. HIT THE SNOW AND DRIZZLE CHANCES HARDEST WHERE
NORTHERLY WINDS PROVIDE ADDITIONAL UPSLOPE LIFTING...SO MAINLY OVER
PORTIONS OF WEST AND NCNTRL UPR MICHIGAN. PASSAGE OF WEAK NORTHERN
STREAM WAVE WITH DEEPER MOISTURE LIKELY ENDS THE FZDZ/DZ REGIME BY
CHRISTMAS EVE EVENING. AS LONG AS LOW PRESSURE SYSTEM OVER CNTRL
GREAT LAKES DOES NOT COME ANY FARTHER WEST...WILL SEE ANY LGT SNOW
TAPERING OFF BY MIDNIGHT FOR FAR EAST. TOTAL SNOW ACCUMS AS IT
STANDS NOW COULD BE A FEW INCHES TOWARD KERY. THIS IDEA MATCHES WPC
SNOW FORECASTS FAIRLY WELL. TEMPS THROUGOUT THE WED-WED NIGHT TIME
FRAME REMAIN MILD WITH LOW TO MID 30S ON WED AND UPR 20S TO LOW 30S
WED NIGHT.
ON CHRISTMAS DAY...A COOLISH AIRMASS ALOFT /H85 TEMPS -10C/ IN WAKE
OF THE NORTHERN STREAM TROUGH MAY RESULT IN WEAK LAKE ENHANCED SNOW
FOR WNW FLOW AREAS...BUT OTHERWISE APPEARS TO BE A QUIET DAY WITH
CONTINUED ABOVE NORMAL TEMPS IN THE LOW-MID 30S. TIGHTER PRESSURE
GRADIENT ON WEST EDGE OF DEEPENING LOW LIFTING TOWARD JAMES BAY MAY
LEAD TO SOME GUSTY WINDS AND BLSN OVER FAR EAST CWA TO START THE
DAY...BUT THIS SHOULD EASE QUICKLY.
ON TO THE NEXT SYSTEM THAT COULD IMPACT THE UPPER GREAT LAKES. TREND
OF DEEPER/SLOWER SHORTWAVE TROUGH OVER CNTRL CONUS BY FRIDAY IS
EMERGING. RESULT IS MORE DEVELOPED SFC LOW PRESSURE SYSTEM AND AREA
OF LGT TO MODERATE SNOW ORIENTED SW-NE ON NORTHWEST SIDE OF H85 LOW.
MIXING RATIOS INTO THE SYSTEM A SHADE OVER 2 G/KG AND SLR/S WILL BE
HIGHER AS COLDER AIR WILL HAVE WORKED FM THE NORTHERN PLAINS TO THE
UPPER GREAT LAKES. OVERALL A SWATH OF MODERATE SNOW MAY OCCUR...
PEGGED TO MAINLY IMPACT WESTERN SECTIONS OF UPR MICHIGAN FRIDAY
AFTN/FRIDAY NIGHT. ONSHORE FLOW AND TEMPS COLD ENOUGH COULD LEAD TO
LAKE ENHANCEMENT OVER WESTERN TIER OF UPR MICHIGAN FOR AREAS FAVORED
BY NW WINDS. WILL CONTINUE TO MENTION IN THE HWO.
LAKE EFFECT LIKELY IN THE WAKE OF THIS SYSTEM AS TEMPS CONTINUE TO
COOL WITH READINGS BLO -15C BY LATE IN THE WEEKEND. BLYR DRYING OUT
AND INCREASING SFC RIDGING WILL LIKELY PUT CRIMP INTO THE LES. KEPT
POPS SIMILAR TO PREVIOUS FORECAST FOR THE WEEKEND...WITH LIKELY POPS
IN THE NW FLOW AREAS NEAR LK SUPERIOR. AFTER THE MILD DAYTIME TEMPS
THIS WEEK...THE COOLING TEMPS WILL BE NOTICABLE WITH READINGS ONLY
IN THE TEENS TO LOWER 20S BY SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 644 AM EST TUE DEC 23 2014
EXPECT LIFR CONDITIONS TO PREDOMINATE THIS FCST PERIOD AT ALL 3 TAF
SITES AS A STRONG DISTURBANCE MOVING THRU THE GREAT LKS BRINGS SOME
SN TO THE AREA TODAY. SINCE IWD WILL BE FARTHER FROM THE TRACK OF
THIS SYSTEM AND THE LLVL ENE WIND INITIALLY DOES NOT PRESENT A SGNFT
UPSLOPE COMPONENT...CONDITIONS THERE EARLY IN THE TAF PERIOD WILL BE
MVFR. BUT AS THE LLVL WINDS SHIFT TOWARD A MORE FAVORABLE UPSLOPE NE
DIRECTION AND DEEPER MSTR/HEAVIER SN ARRIVES BY AFTN...CONDITIONS
THERE SHOULD FALL TO LIFR AS WELL. THE BEST CHANCE FOR LOWER VSBYS
APRCHG VLIFR WL BE SAW LATE THIS MRNG INTO EARLY AFTN AS A BAND OF
VERY HEAVY SN CLOSER TO THE TRACK OF THE RESPONSIBLE DISTURBANCE
MOVES OVHD. GUSTY ENE WINDS MAY CAUSE ENUF BLSN AT THE EXPOSED CMX
LOCATION TO CAUSE VSBYS THERE TO FALL TOWARD VLIFR AS WELL...
ESPECIALLY IN THE EARLY AFTN WHEN THE STRONGER DYNAMIC FORCING WL
IMPACT THAT LOCATION. THE DISTURBANCE/DEEP MSTR WL EXIT LATE TODAY/
TNGT...SO THE SN WL DIMINISH. BUT LINGERING ALBEIT WEAKENING CYC NNE
FLOW OFF LK SUP WL MAINTAIN OVC LO CLDS/LIFR CIGS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EST TUE DEC 23 2014
LOW PRESSURE SLOWLY LIFTING OVER THE WESTERN GREAT LAKES TODAY WILL
RESULT IN EAST WINDS ON LK SUPERIOR...PERHAPS GUSTING TO GALE FORCE
OVER WESTERN LK SUPERIOR. WINDS WILL DIMINISH TONIGHT INTO WEDNESDAY
AS THE LOW SLIDES DIRECTLY OVER LAKE SUPERIOR. AS THE LOW WEAKENS...
ANOTHER MUCH STRONGER DEEPENING LOW WILL LIFT NORTHWARD OVER THE
CENTRAL GREAT LAKES BY WEDNESDAY NIGHT. EXPECT NORTHERLY WINDS TO
INCREASE TO 30 KTS OVER EASTERN LK SUPERIOR CLOSER TO THE STRONG LOW
PRESSURE SYSTEM. THE PRESSURE GRADIENT WILL BE TIGHEST ON THE WEST
FLANK OF THIS LOW LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING.
GALE GUSTS COULD OCCUR OVER EASTERN LK SUPERIOR AT THAT TIME. WINDS
BACK NW ON THURSDAY AND DIMINISH TO LESS THAN 20 KTS BY AFTN AS THE
LOW PRESSURE SYSTEM MOVES FARTHER AWAY FM THE AREA. ANOTHER LOW
PRESSURE SYSTEM WILL SLIDE OUT OF THE PLAINS OVER THE UPPER GREAT
LAKES FRIDAY INTO SATURDAY. NORTHERLY WINDS WILL BACK NORTHWEST AND
MAY REACH 30 KTS ON SATURDAY...MAINLY OVER EAST HALF OF LK SUPERIOR.
WINDS DIMINISH AGAIN BY SUNDAY AS HIGH PRESSURE BEGINS TO BUILD
TOWARD THE REGION FM THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>007-009>011-084-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ012>014.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...JLA
AREA FORECAST DISCUSSION
NWS GLASGOW MT
901 AM MST TUE DEC 23 2014
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
SKIES HAVE CLEARED A BIT MORE THAN WHAT IS FORECASTED. MODELS ARE
NOT HAVING A GOOD HANDLE ON THIS VERY WELL...SO HAD TO USE THE
CONCEPTUAL MODEL. TWEAKED WINDS TO LATEST MODEL DATA. REST OF
FORECAST LOOKED GOOD. TFJ
PREVIOUS DISCUSSION...
THE SYNOPTIC PATTERN BEGINS WITH A LARGE TROUGH OF COLD AIR OVER
CENTRAL CONUS AND AN EQUALLY LONG-WAVE RIDGE OVER THE WEST. THIS
PLACES NORTHWEST FLOW ALOFT OVER NORTHEAST MONTANA. THERE ARE
STILL LINGERING EFFECTS FROM THE DEPARTING WINTER STORM...MAINLY
LIGHT RADAR ECHOES NEAR THE YELLOWSTONE RIVER VALLEY AREA. WITH
ONLY LIGHT ECHOES THE WINTER WEATHER ADVISORY WAS CANCELLED EARLY
THIS MORNING. THE APPROACHING RIDGE IS PUSHING WARM/COLD
BOUNDARY EAST AS A WARM FRONT THAT WILL OVERRUN THE LOCAL REGION
TONIGHT AND WEDNESDAY.
TODAY...WILL NOT SEE MUCH TEMPERATURES DIFFERENCE FROM
MONDAY...BUT WIND WILL BE LIGHT...ELIMINATING THE WIND CHILL
EFFECT. ALSO EXPECT CLEARING FROM THE WEST.
TONIGHT...THE WARM FRONT WILL INCREASE 850 MB TEMPERATURES WHICH
WILL RISE TO AROUND +2C TO +4C...AS A SURFACE TROUGH ALSO SLIDES
DOWN FROM CANADA. SOME PACIFIC MOISTURE RIDING THE TOP OF THE
FLATTENING RIDGE WILL MAKE IT INTO THE REGION FOR POSSIBLE LIGHT
FREEZING RAIN.
WEDNESDAY...AN UPPER DISTURBANCE MOVING ACROSS THE PRAIRIE
PROVINCES WILL SEND THE COLD BOUNDARY SOUTH AND ACT AS A COLD
FRONT. MODELS ARE SHOWING ANOTHER TROUGH SLAMMING INTO THE WEST
COAST. THIS WILL SEND MORE MOISTURE OVER THE DIVIDE...REACHING
PORTIONS OF NEMONT WITH MIXED PRECIPITATION. THE FREEZING RAIN
POTENTIAL SUGGESTS THAT SOME TRAVEL MAY BE IMPACTED BY ICE THROUGH
WEDNESDAY MORNING BEFORE TEMPERATURES RISE ABOVE FREEZING.
WEDNESDAY NIGHT AND THURSDAY...AS THE FRONT MOVES SOUTH SO DOES
THE PRECIPITATION. A BLEND OF THE MODELS ARE SHOWING BASICALLY THE
SOUTHWEST HALF OF THE CWA GETTING THE MOST QPF. TEMPERATURE
PROFILES SUGGEST ALL SNOW. THIS IS THE CHRISTMAS STORM THAT HAS
BEEN ADVERTISED FOR THE REGION. THE BRUNT OF IT FOR US WILL HAPPEN
THROUGH THURSDAY MORNING THEN RAPIDLY TAPER OFF FROM THE NORTH BY
AFTERNOON. BASED ON QPF AND SNOW RATIO THE TOTAL SNOW COULD RANGE
FROM AROUND 3.5 INCHES IN THE SOUTHWEST ZONES TO LESS THAN A
HALF INCH IN THE NORTHEAST ZONES. WITH MODELS COMING TOGETHER MORE
THE UNCERTAINTY IS DIMINISHING FOR A SNOW EVENT WEDNESDAY NIGHT
AND THURSDAY SPREAD OVER MOST OF CENTRAL AND EASTERN MONTANA.
SCT
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
UPPER RIDGE BUILDING ALONG THE WEST COAST WILL OPEN THE REGION TO
THE ARCTIC...RESULTING IN MUCH COLDER TEMPERATURES BETWEEN
CHRISTMAS AND NEW YEARS.
MIDWEEK GREAT BASIN STORM SYSTEM SHOULD BE WINDING DOWN ACROSS
NORTHERN MONTANA BY THURSDAY EVENING WITH CANADIAN HIGH PRESSURE
PUSHING INTO THE NORTHERN PLAINS. A SECONDARY SHORTWAVE DROPPING
ACROSS ALBERTA INTO THE LONGWAVE TROF COULD BRING A FEW FLURRIES
OR SNOW SHOWERS ON FRIDAY.
NEXT SHORTWAVE SLIDES DOWN THE CANADIAN ROCKIES FOR THE WEEKEND.
SLIGHT WARM FRONT/CHINOOK BOUNDARY DEVELOPS IN CENTRAL MONTANA ON
SATURDAY WITH WAVE SLIDING SOUTH ALONG THE BOUNDARY SATURDAY
NIGHT. ANOTHER SURGE OF COLD AIR FOLLOWS ALONG WITH PACIFIC
MOISTURE STREAMING EAST OF THE DIVIDE...SETTING THE STAGE FOR
UPSLOPE AND COLD AIR ADVECTION SNOW ON SUNDAY. BEST CHANCE WILL BE
THE SOUTHWEST WITH THE ADDITION OF TERRAIN INFLUENCES.
COLDEST AIR COMES OVER THE REGION ON MONDAY WITH THE UPPER TROF
AXIS. CANADIAN HIGH FOLLOWS WITH DRIER AIRMASS MONDAY NIGHT FOR A
GOOD POSSIBILITY OF TEMPERATURES DROPPING BELOW ZERO ACROSS MOST
OF THE CWA BY TUESDAY MORNING. EBERT
&&
.AVIATION...
FLIGHT CATEGORY: MAINLY VFR... ISOLATED MVFR POSSIBLE.
SYNOPSIS: A LOW PRESSURE SYSTEM CONTINUES TO EXIT THE REGION VIA
SOUTH DAKOTA WITH SOME LINGERING AVIATION ISSUES EARLY THIS
MORNING AT KOLF AND KSDY. LOW CLOUD DECK WILL GRADUALLY MOVE EAST
AND EXIT THE REMAINING TAFS.
FOG: AN ISOLATED CHANCE FOR FOG AT KOLF EXISTS TONIGHT IN BOTH
THE RAP AND NAMDNG5 MODELS. HOWEVER... WITH MID TO HIGH CLOUDS MOVING INTO
THE AREA AT PEAK FOG HOURS.... CONFIDENCE IS TOO LOW TO INCLUDE IN
THE TAF AT THIS TIME.
WINDS: OUT OF THE WEST FROM 5 TO 15 KTS THROUGH THIS AFTERNOON...
BACKING TO THE SOUTH AND SOUTHWEST AND DECREASING TO 5 TO 10 KTS
OVERNIGHT.
GAH
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1035 AM EST TUE DEC 23 2014
.SYNOPSIS...
LIGHT RAIN AND PATCHY DRIZZLE WILL CONTINUE THIS AFTERNOON AND
EVENING AS A WEAK SURFACE LOW MOVES UP THE EAST COAST. A STRONGER
STORM SYSTEM MOVING UP FROM THE GULF OF MEXICO WILL BRING A MORE
WIDESPREAD RAIN TO CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA
LATE TONIGHT THROUGH EARLY CHRISTMAS MORNING. A STRONG FRONT WILL
MOVE THROUGH CHRISTMAS MORNING BRINGING STRONG GUSTY WINDS TO THE
AREA, WITH LINGERING RAIN SHOWERS MIXING WITH SNOW SHOWERS.
&&
.NEAR TERM /THROUGH TONIGHT/...
RADARS SHOW A BAND OF RAIN LIFTING NORTHEAST INTO CENTRAL NY AND
NRN PA IN ASSCTN WITH A SHORT WAVE THAT WAS RIPPLING NORTHEASTWARD
INTO THE NE U.S. THIS FEATURE WAS SEEN AS SOME ENHANCED CLOUD TOPS
ON THE IR IMAGERY AT THIS TIME. THIS FEATURE WILL RACE OFF TO THE
NORTHEAST BY EARLY AFTERNOON AND THE RAIN WILL GO WITH IT LEAVING
BEHIND PATCHY AREAS OF LIGHT RAIN AND DRIZZLE FOR THE REST OF THE
AFTERNOON AND MUCH OF TONIGHT. A FEW PATCHES OF STEADIER RAIN CUD
ADVECT THRU THE REGION AS PER HRRR LATE AFTERNOON/EVENING. SO WILL KEEP
CHC POPS GOING FOR AFTERNOON AND MUCH OF TONIGHT TO COVER ANY
POCKETS OF LIGHT RAIN/DRIZZLE OR A BRIEF STEADIER PD OF RAIN. MAIN
SHIELD OF RAIN ARRIVES BTWN 8 AND 12Z WED AS ONE OF THE FIRST
SIGNIFICANT MAIN WAVES RIDES NORTHEASTWARD AHEAD OF THE DIGGING
TROUGH THAT DROPS INTO THE SRN U.S LATER TONIGHT. THIS WAVE WILL
ACCELERATE A SRLY LLJ WHICH ADVECTS PLENTY OF MOISTURE NORTHWARD
INTO NY AND PA AS IT GLIDES UP THE ISENTROPES LATE TONIGHT. IN
ADDTN...UPR DVRG INCREASES AS WELL. THIS IS RECIPE FOR A
WIDESPREAD AREA OF RAIN TO OVERSPREAD THE ENTIRE AREA BY 12Z WED. I
ALSO KEEP PATCHY DENSE FOG IN THE POCONOS AND CATSKILLS IN THE
HIGHER TERRAIN AS THE LL FLOW IS SERLY AND UPSLOPING UNTIL THE
HEAVIER RAIN ARRIVES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
335 AM UPDATE...
CWA WL BE IN A LULL THE FIRST PART OF TONIGHT AS SFC LOW ALONG THE
ERN SEABOARD FILLS AND SYSTEM OVR NRN GULF GATHERS STRENGTH. AIRMASS
WL CONTINUE TO BE MOIST AND JUICY WITH POTENTIAL FOR LGT RAIN/DZ/FOG
THRU 06Z WED. BY 12Z EXPECT H5 LOW WL EXTND ACRS THE CNTR PART OF
THE NATION WITH ~997MB SFC LOW LOCATED IN VICINITY OF OH VLY. THIS
WL ALLOW DEEP LYR MOISTURE TO MV IN FM THE SOUTH LKLY BTWN 09Z AND
12Z. THUS HV RAMPED POPS TO LKLY BY 09Z AND NR 100 POPS BY 12Z WED.
PW VALUES FM NAM AND GEFS EXPECTED TO BE BTWN 3-4 STANDARD
DEVIATIONS ABV NORMAL LATE TUE NGT. THIS LINES UP WELL WITH ALL
MODELS, INCLUDING HIRES AND 4KM NAM, SHOWING THE FIRST SURGE OF RAIN
TWD 12Z.
H5 LOW WL GO NEGATIVE ON WED WITH GOM WIDE OPEN AS 40-50KT H8 JET
PUMPS MOISTURE INTO REGION DRG THE DAY. PW VALUES DRG THE AFTN HRS
INCREASE TO 4-5 SD ABV NORMAL VALUES WITH V-COMPONENT OF H8 WINDS
RANGING FM 2-3 SD DRG THE DAY. COUPLED JET REGION OF H2 SPEED MAX
LOOKS TO BE TO THE WEST OF CWA ON WED. THAT BEING SAID, WL CONTINUE
WITH MENTION OF MODERATE RAIN FOR XMAS EVE.
FROPA LOOKS TO OCCUR ARND 09Z ON CHRISTMAS MRNG. CANNOT RULE OUT A
RUMBLE OF THUNDER IMMEDIATELY AHD OF FRONT, HWVR THINK CHCS ARE
MARGINAL SO WL NOT INLUDE IN GRIDS AT THIS TIME. AS INVERSION
BREAKS, STRONG WINDS ALOFT WL BE ABLE TO MIX DOWN AS IT MVS THRU
WITH A GUSTY SW WIND LOOKING LIKELY LATE WED NIGHT WHICH WL GIVE
SANTA A HARD TIME. LATER SHIFTS MAY NEED TO CONSIDER WIND HEADLINES
FOR LATE WED NGT INTO THURSDAY BUT STILL TOO EARLY AT THIS POINT.
TEMPS WL VRY SLOWLY FALL ON THURSDAY WITH A SLOW RAIN/SNOW MIX
WORKING IN THROUGHOUT CHRISTMAS DAY. NOT EXPECTING ANYTHING MORE
THAN A TRACE OF SNOW TO FALL ON THURSDAY WITH A DUSTING POSSIBLE ON
280-290 FLOW ACRS LK ZONES. HWVR INVERSION WL BE LOWERING DRG THE
EVNG HRS SO NOT EXPECTING MUCH IN THE WAY OF ACCUMS THRU THE END OF
THE SHORT TERM.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
1 AM UPDATE...
LITTLE CHANGE. FOLLOWED WPC GUIDANCE. FRI/FRI NGT DRY THEN RAIN
MOVES BACK IN LATE SAT THEN CHANGES TO SNOW FROM NW TO SE SUN AND
SUN NGT. MOSTLY DRY MON/TUE. TEMPERATURES ABOVE NORMAL FALLING TO
NORMAL MON/TUE.
PREVIOUS DISCUSSION...
STRONG COLD FRONT PASSES THE REGION THURSDAY MORNING. MODELS ARE
IN REASONABLE AGREEMENT WITH THIS FEATURE AND SUGGEST THE MOST
SIGNIFICANT IMPACT WILL BE SW-W WINDS IN THE STRONG COLD ADVECTION
THURSDAY AFTERNOON. WINDS MAY GUST AT TIMES 35-45 MPH. THERE IS
ALSO A GOOD SIGNAL SHOWING UP FOR A NARROW COLD FRONTAL RAIN BAND
PHENOMENA MOVING THROUGH BETWEEN 12Z-18Z. THIS FEATURE ALONE MAY
CAUSE CONVECTIVE WIND ACCELERATIONS AND SCATTERED DAMAGE/POWER
OUTAGES. LOOKING FOR A NON-DIURNAL TEMPERATURE TREND FROM WEDS
NIGHT-THURSDAY WITH MAXES FOR WEDS/THURS PROBABLY A FEW HOURS
EITHER SIDE OF MIDNIGHT AS STRONG WARM SECTOR SURGES INTO AREA.
OUTSIDE OF THIS FEATURE...THE TEMPERATURES ARE TRENDING SLIGHTLY
WARMER SO A CHANGEOVER FROM PERIODS OF RAIN TO SCATTERED RAIN/SNOW
SHOWERS SEEMS MORE LIKELY THAN A SHARP TURNOVER TO ALL SNOW. IN
FACT...A SIGNIFICANT DRY SLOT MAY CUT PRECIPITATION OFF FOR MUCH
OF THE MORNING BEFORE THE INSTABILITY SHOWERS ASSOCIATED WITH THE
COLD POOL KICK IN FOR THURSDAY AFTERNOON AND NIGHT.
THE REMAINDER OF THE WEEK FEATURES SOME WEAK LAKE EFFECT RESPONSE
MAINLY NORTH OF CENTRAL NY ON FRIDAY...THEN RIDGING AND GENERALLY
NEAR TO ABOVE NORMAL TEMPERATURES INTO SATURDAY. BIG MODEL
DISCREPANCIES THEN CONTINUE TO SHOW UP BETWEEN THE ECMWF AND GFS
WHERE THE ECMWF BRINGS A QUICK TN VALLEY RUNNER TO THE MIDDLE
ATLANTIC COAST BY SUNDAY AFTERNOON. THE GFS AND GEFS ENSEMBLES
FEATURE A MUCH FLATTER SWLY FLOW AND SFC HIGH PRESSURE. THE
CANADIAN GGEM DEFINITELY LEANS WITH THE EURO WITH LOW PRES ON THE
COAST SUNDAY AFTERNOON. AT THIS TIME...WILL BLANKET WITH LOW CHC
POPS FOR SNOW SHOWERS GIVEN THE HIGH LVL OF UNCERTAINTY.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
630 AM UPDATE...
RAIN OVER THE AREA NOW WILL CONTINUE THROUGH THE FIRST 24 HOURS AT
LEAST. CONDITIONS MOSTLY MVFR CIGS AND VFR VSBYS.
BGM HAS IFR CIGS AND VFR VSBYS. MOST CONFIDENT HERE THAT CIGS WILL
REMAIN IFR WELL INTO WED. CIGS WILL BE AT OR CLOSE TO FLIGHT
MINIMUMS ESPECIALLY EARLY THIS MORNING. AS RAIN INCREASES TONIGHT
VSBYS MAY FALL TO IFR.
AVP WILL HAVE CIGS AROUND 1500 FT SO MVFR AND VSBYS VFR.
POSSIBILITY OF SOME IFR CIGS FIRST 3 HOURS.
ELM ALSO HAS IFR CIGS. EXTRA FUEL WITH ALTERNATE REQUIRED. CIGS
SHOULD RISE TO MVFR THIS AFTN BUT THEN FALL BACK TO IFR LATE EVE.
ITH HAS A 1K FT CIG. EXPECT THE CIG TO BECOME IFR THIS MORNING.
IMPROVEMENT TO MVFR LATE TODAY AND EVE THEN FALLING BACK TO IFR
LATE TONIGHT. VSBYS VFR BECOMING MVFR.
RME NOW MVFR CIGS BUT EXPECTED TO FALL TO IFR AT TIMES THIS
MORNING THEN FALL TO IFR TONIGHT.
SYR HAS THE BEST CONDITIONS. MVFR CIGS THROUGHOUT WITH VSBYS
FALLING TO MVFR IN STEADY RAIN STARTING THIS AFTN.
OUTLOOK...
WED TO WED NGT... MVFR LIKELY...CHANCE IFR. PERIODS OF RAIN.
THU...VFR. VERY WINDY AFTERNOON.
FRI/SAT...VFR. CHC SHRA SAT.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN/PVF
NEAR TERM...DJN
SHORT TERM...PVF
LONG TERM...JAB/TAC
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1004 AM EST TUE DEC 23 2014
.SYNOPSIS...
LOW PRESSURE OVER NORTHEASTERN IOWA WILL WEAKEN AS IT MOVES TO THE
NORTHEAST THROUGH THE AFTERNOON. A SECONDARY AREA OF LOW PRESSURE
WILL DEVELOP NEAR THE GULF COAST TODAY AND UNDERGO RAPID DEEPENING
AS IT TRACKS NORTH TOWARDS LAKE ERIE BY WEDNESDAY NIGHT. THIS
SYSTEM WILL PULL A STRONG COLD FRONT ACROSS THE AREA WITH GUSTY
WINDS LATE WEDNESDAY AND WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AT THIS POINT HAVE ONLY MADE MINOR CHANGES TO THE GRIDS TO REFLECT
CURRENT CONDITIONS.
70 KNOT 5H JET IS NOSING INTO SOUTHERN OHIO WHICH SHOULD CONTINUE
TO PROVIDE SOME LIFT ACROSS THE SOUTHEASTERN THIRD OF THE COUNTY
WARNING AREA. HAVE EITHER SCATTERED OR LIKELY WORDING FOR THIS
REGION. STILL CANT RULE OUT A FEW SHOWERS ELSEWHERE SO KEPT A
CHANCE GOING.
PREVIOUS DISCUSSION...
A WARM FRONT WILL BE MOVING NORTH OF THE AREA TODAY. THE BEST
CHANCE OF SHOWERS WILL BE EARLY THIS MORNING AND THEN LATE THIS
AFTERNOON ACCORDING TO THE HRRR MODEL THAT THE NEXT ROUND OF
SHOWERS WILL BE HEADING TOWARD THE AREA. SOME QUESTION IN THIS BUT
IT SEEMS REASONABLE WITH THE TROF ASSOCIATED WITH THE LOW WILL BE
MOVING UP. EVEN BETWEEN THE SYSTEMS BATCHES OF RAIN THE AREA WILL
BE IN THE LFQ OF THE JET SO A THREAT OF SHOWERS WILL EXIST.
WITH THE WARM FRONT MOVING NORTH AND EVEN WITH PLENTY OF CLOUDS
AND SOME WIND WENT TOWARD THE WARMER GUIDANCE FOR THE HIGHS BASED
ON WARM AIR COMING UP FROM THE SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
WET AT TIMES THE NEXT FEW DAYS...ABOVE NORMAL TEMPERATURES AND
BECOMING WINDY LATE CHRISTMAS EVE.
MORE SHOWERS WILL BE MOVING THROUGH AHEAD OF THE LOW THAT WILL
MOVE ALONG THE OHIO AND INDIANA BORDER ON WEDNESDAY. SOME QUESTION
HOW MUCH SHOWER ACTIVITY WILL OCCUR ON THE WARM SIDE OF THE LOW.
KEPT HIGH POPS. WE COULD GET INTO A BREAK FROM THE SHOWERS
WEDNESDAY AFTERNOON AS THE FIRST FRONT MOVES THROUGH AND THEN
ANOTHER FRONT WEDNESDAY NIGHT...THAT FRONT MAY HAVE SOME SNOW WITH
IT. THE GFS MOS GUIDANCE SAYS IT WILL BE ALL RAIN...THIS DOES NOT
SEEM REASONABLE BASED ON THE LOW LEVEL THICKNESS AND THE 850 MB
TEMPERATURE DIFFERENCE. WILL LEAVE IT A MIX BUT THIS WILL HAVE TO
BE WATCHED. NONE THE LESS WITH THE SURFACE TEMPERATURE IN THE MID
30S IT WILL BE TOUGH TO ACCUMULATE...MAY BE A LITTLE ON GRASSY
SURFACES. SOME RAIN OR SNOW SHOWERS WILL LINGER MAINLY EAST
THURSDAY MORNING. DRY FRIDAY AND THEN A CHANCE OF RAIN OR SNOW
SHOWERS LATE FRIDAY NIGHT AS ANOTHER FRONT HEADS TOWARD THE AREA.
QPF FOR THIS EVENT FROM TONIGHT THROUGH THURSDAY WILL BE AN INCH OR
LESS OF RAIN. NO FLOODING IS EXPECTED. SOME PONDING OF WATER ON
ROADS MAY OCCUR AS THE GROUND IS SATURATED.
THE WIND IS THE BIGGEST CONCERN FOR LATE WEDNESDAY INTO THURSDAY
MORNING. STILL SOME ISSUES WHETHER THE WINDS WILL JUST BE IN THE
ADVISORY CATEGORY OR WILL NEED A HIGH WIND WARNING. THE COLD
ADVECTION SEEMS STRONG AT FIRST AND WITH 925 MB WINDS IN THE 40 TO
50 KNOT RANGE CONCERNED. SOME OF THE STRONGEST WINDS WILL BE ALONG
THE LAKESHORE. STILL SOME QUESTION WHETHER THE WATCH SHOULD BE
FOR THE WHOLE FORECAST AREA OR JUST ALONG THE LAKESHORE. AT THIS
TIME WILL NOT ISSUE THE WATCH AS SOME OF THE STRONG WINDS COULD
OCCUR WITH THUNDER AND SEVERE THUNDERSTORM WARNINGS WILL BE
NEEDED. ADDED CHANCE OF THUNDERSTORMS FOR WEDNESDAY AFTERNOON.
TEMPERATURES ARE TOUGH ON WEDNESDAY. WENT TOWARD THE WARMER GUIDANCE.
THESE HIGHS WILL BE A FEW DEGREES BELOW THE RECORD HIGHS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
UPPER LEVEL TROUGHS THREATEN TO STRIKE THE AREA BY THE END OF THE
WEEK AND THEN FLATTEN OUT AS THEY REACH THE FORECAST AREA. FLOW
TRIES TO BECOME MORE ZONAL BY SUNDAY EVENING ACROSS MUCH OF THE
COUNTRY. BUT THEN AS WE APPROACH THE END OF THE YEAR...YET ANOTHER
TROUGH SWINGS THROUGH THE FORECAST AREA. THIS SYSTEM WILL BE RATHER
QUICK TO MOVE THROUGH THE REGION AND WILL BRING WITH IT THE
POTENTIAL FOR A GLANCING BLOW OF COLDER AIR TO THE REGION.
IN THE MEAN TIME...STILL EXPECTING TEMPERATURES TO REMAIN ABOVE
NORMAL THROUGH THE FORECAST PERIOD. LOW PRESSURE IS PROGGED TO MOVE
NORTHEAST INTO THE CENTRAL GREAT LAKES BY SATURDAY MORNING. THIS
STORM SYSTEM WILL FORCE A COLD FRONT TO MOVE EAST ACROSS THE AREA
SATURDAY. A REINFORCING SHOT OF COLD AIR WILL PUSH SOUTHEAST INTO
THE AREA SATURDAY NIGHT INTO SUNDAY MORNING. HOWEVER...THE SECONDARY
FRONT IS EXPECTED TO STALL OVER EXTREME NORTHERN OHIO AND NORTHWEST
PENNSYLVANIA. HIGH PRESSURE WILL MOVE EAST INTO THE SOUTHERN GREAT
LAKES BY SUNDAY AFTERNOON AND THEN LIFT NORTHEAST TO QUEBEC BY
SUNDAY NIGHT. TRUE ARCTIC AIR MASS WILL NOT REALLY PUSH INTO THE
AREA DURING THIS FORECAST PERIOD. NEXT BEST SHOT OF COLD AIR WILL
NOT ARRIVE UNTIL WEDNESDAY IN TIME FOR THE NEW YEAR. EVEN THIS SHOT
OF COLD AIR APPEARS TO BE A GLANCING BLOW AND QUICKLY RETREATS TO
THE EAST.
THE COLD FRONT EXPECTED TO MOVE EAST INTO THE REGION ON SATURDAY
WILL HAVE LIMITED MOISTURE AT BEST AND MAY LIMIT THE AMOUNT OF
PRECIPITATION WE SEE WITH THE FEATURE.
DRIER AIR QUICKLY PUSHES INTO THE REGION FROM THE NORTHWEST IN
ADVANCE OF THE HIGH PRESSURE AND THIS SHOULD BRING A RETURN BACK TO
FAIR WEATHER TO THE REGION SUNDAY NIGHT INTO MONDAY. SOME LAKE
EFFECT SNOW SHOWER ACTIVITY IS POSSIBLE SATURDAY NIGHT INTO SUNDAY
IN NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA IN THE COLD AIR
ADVECTION.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
WARM FRONT LIFTING NORTH AT THIS TIME FORCING PRECIPITATION TO
MOVE NORTHEAST OF THE AREA AT THIS TIME. LITTLE TO NO
PRECIPITATION AT THIS TIME BEHIND THE FRONT AND NOT EXPECTING ANY
THING MORE THAN JUST SOME PATCHY DRIZZLE THROUGH MUCH OF THE DAY.
CEILINGS BEGIN TO LOWER FROM WEST TO EAST LATER IN THE DAY INTO
TONIGHT AS NEXT STORM SYSTEM APPROACHES FROM THE SOUTHWEST.
EXPECTING WINDS TO REMAIN LIGHT THROUGH THE DAY INTO TONIGHT OVER
MUCH OF THE AREA. HIGHEST WINDS WILL REMAIN CONFINED TO ERIE
PENNSYLVANIA NEAR THE LAKE.
.OUTLOOK...NON VFR POSSIBLE THROUGH THURSDAY.
&&
.MARINE...
GALE WATCHES HAVE ALREADY BEEN POSTED FOR WEDNESDAY AFTERNOON INTO
THURSDAY MORNING AS WINDS ON THE LAKE ARE EXPECTED TO INCREASE TO 35
TO 40 KNOTS. THIS IS IN RESPONSE TO STORM SYSTEM EXPECTED TO MOVE
NORTHEAST INTO THE FORECAST AREA AND AFFECT THE LAKE. GRADIENT WILL
BE QUITE STRONG AND THIS WILL CAUSE THE STRONGER WINDS ON THE LAKE.
AT THIS TIME...DO NOT EXPECT TO SEE STORM FORCE WINDS ON THE LAKE.
WINDS WILL GRADUALLY DIMINISH THURSDAY AFTERNOON AND THURSDAY NIGHT.
SOUTHERLY FLOW QUICKLY RETURNS BY THURSDAY NIGHT INTO FRIDAY AS HIGH
PRESSURE SCOOTS BY TO THE SOUTH OF THE AREA. THIS SHOULD SET UP SOME
WARM AIR ADVECTION OVER THE LAKE REDUCING THREAT OF HIGH WAVES BY
FRIDAY. NEXT STORM SYSTEM APPROACHES FROM THE WEST FORCING A COLD
FRONT ACROSS THE LAKE ON SATURDAY. WINDS AHEAD OF THE COLD FRONT
ARE EXPECTED TO INCREASE ON SATURDAY AND WILL LIKELY NEED SMALL
CRAFT ADVISORIES BY THEN.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY AFTERNOON
FOR LEZ061-142>149-162>169.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA/MULLEN
SHORT TERM...KIELTYKA
LONG TERM...LOMBARDY
AVIATION...LOMBARDY
MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
628 AM EST TUE DEC 23 2014
.SYNOPSIS...
A BROAD AREA OF LOW PRESSURE OVER THE NORTHERN PLAINS WILL LIFT A
WARM FRONT NORTH ACROSS THE AREA TODAY. A SECONDARY AREA OF LOW
PRESSURE WILL DEVELOP NEAR THE GULF COAST TODAY AND UNDERGO RAPID
DEEPENING AS IT TRACKS NORTH TOWARDS LAKE ERIE BY WEDNESDAY NIGHT.
THIS SYSTEM WILL PULL A STRONG COLD FRONT ACROSS THE AREA WITH
GUSTY WINDS LATE WEDNESDAY AND WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A WARM FRONT WILL BE MOVING NORTH OF THE AREA TODAY. THE BEST CHANCE
OF SHOWERS WILL BE EARLY THIS MORNING AND THEN LATE THIS AFTERNOON
ACCORDING TO THE HRRR MODEL THAT THE NEXT ROUND OF SHOWERS WILL BE
HEADING TOWARD THE AREA. SOME QUESTION IN THIS BUT IT SEEMS
REASONABLE WITH THE TROF ASSOCIATED WITH THE LOW WILL BE MOVING
UP. EVEN BETWEEN THE SYSTEMS BATCHES OF RAIN THE AREA WILL BE IN
THE LFQ OF THE JET SO A THREAT OF SHOWERS WILL EXIST.
WITH THE WARM FRONT MOVING NORTH AND EVEN WITH PLENTY OF CLOUDS
AND SOME WIND WENT TOWARD THE WARMER GUIDANCE FOR THE HIGHS BASED
ON WARM AIR COMING UP FROM THE SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
WET AT TIMES THE NEXT FEW DAYS...ABOVE NORMAL TEMPERATURES AND
BECOMING WINDY LATE CHRISTMAS EVE.
MORE SHOWERS WILL BE MOVING THROUGH AHEAD OF THE LOW THAT WILL
MOVE ALONG THE OHIO AND INDIANA BORDER ON WEDNESDAY. SOME QUESTION
HOW MUCH SHOWER ACTIVITY WILL OCCUR ON THE WARM SIDE OF THE LOW.
KEPT HIGH POPS. WE COULD GET INTO A BREAK FROM THE SHOWERS
WEDNESDAY AFTERNOON AS THE FIRST FRONT MOVES THROUGH AND THEN
ANOTHER FRONT WEDNESDAY NIGHT...THAT FRONT MAY HAVE SOME SNOW WITH
IT. THE GFS MOS GUIDANCE SAYS IT WILL BE ALL RAIN...THIS DOES NOT
SEEM REASONABLE BASED ON THE LOW LEVEL THICKNESS AND THE 850 MB
TEMPERATURE DIFFERENCE. WILL LEAVE IT A MIX BUT THIS WILL HAVE TO
BE WATCHED. NONE THE LESS WITH THE SURFACE TEMPERATURE IN THE MID
30S IT WILL BE TOUGH TO ACCUMULATE...MAY BE A LITTLE ON GRASSY
SURFACES. SOME RAIN OR SNOW SHOWERS WILL LINGER MAINLY EAST
THURSDAY MORNING. DRY FRIDAY AND THEN A CHANCE OF RAIN OR SNOW
SHOWERS LATE FRIDAY NIGHT AS ANOTHER FRONT HEADS TOWARD THE AREA.
QPF FOR THIS EVENT FROM TONIGHT THROUGH THURSDAY WILL BE AN INCH OR
LESS OF RAIN. NO FLOODING IS EXPECTED. SOME PONDING OF WATER ON
ROADS MAY OCCUR AS THE GROUND IS SATURATED.
THE WIND IS THE BIGGEST CONCERN FOR LATE WEDNESDAY INTO THURSDAY
MORNING. STILL SOME ISSUES WHETHER THE WINDS WILL JUST BE IN THE
ADVISORY CATEGORY OR WILL NEED A HIGH WIND WARNING. THE COLD
ADVECTION SEEMS STRONG AT FIRST AND WITH 925 MB WINDS IN THE 40 TO
50 KNOT RANGE CONCERNED. SOME OF THE STRONGEST WINDS WILL BE ALONG
THE LAKESHORE. STILL SOME QUESTION WHETHER THE WATCH SHOULD BE
FOR THE WHOLE FORECAST AREA OR JUST ALONG THE LAKESHORE. AT THIS
TIME WILL NOT ISSUE THE WATCH AS SOME OF THE STRONG WINDS COULD
OCCUR WITH THUNDER AND SEVERE THUNDERSTORM WARNINGS WILL BE
NEEDED. ADDED CHANCE OF THUNDERSTORMS FOR WEDNESDAY AFTERNOON.
TEMPERATURES ARE TOUGH ON WEDNESDAY. WENT TOWARD THE WARMER GUIDANCE.
THESE HIGHS WILL BE A FEW DEGREES BELOW THE RECORD HIGHS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
UPPER LEVEL TROUGHS THREATEN TO STRIKE THE AREA BY THE END OF THE
WEEK AND THEN FLATTEN OUT AS THEY REACH THE FORECAST AREA. FLOW
TRIES TO BECOME MORE ZONAL BY SUNDAY EVENING ACROSS MUCH OF THE
COUNTRY. BUT THEN AS WE APPROACH THE END OF THE YEAR...YET ANOTHER
TROUGH SWINGS THROUGH THE FORECAST AREA. THIS SYSTEM WILL BE RATHER
QUICK TO MOVE THROUGH THE REGION AND WILL BRING WITH IT THE
POTENTIAL FOR A GLANCING BLOW OF COLDER AIR TO THE REGION.
IN THE MEAN TIME...STILL EXPECTING TEMPERATURES TO REMAIN ABOVE
NORMAL THROUGH THE FORECAST PERIOD. LOW PRESSURE IS PROGGED TO MOVE
NORTHEAST INTO THE CENTRAL GREAT LAKES BY SATURDAY MORNING. THIS
STORM SYSTEM WILL FORCE A COLD FRONT TO MOVE EAST ACROSS THE AREA
SATURDAY. A REINFORCING SHOT OF COLD AIR WILL PUSH SOUTHEAST INTO
THE AREA SATURDAY NIGHT INTO SUNDAY MORNING. HOWEVER...THE SECONDARY
FRONT IS EXPECTED TO STALL OVER EXTREME NORTHERN OHIO AND NORTHWEST
PENNSYLVANIA. HIGH PRESSURE WILL MOVE EAST INTO THE SOUTHERN GREAT
LAKES BY SUNDAY AFTERNOON AND THEN LIFT NORTHEAST TO QUEBEC BY
SUNDAY NIGHT. TRUE ARCTIC AIR MASS WILL NOT REALLY PUSH INTO THE
AREA DURING THIS FORECAST PERIOD. NEXT BEST SHOT OF COLD AIR WILL
NOT ARRIVE UNTIL WEDNESDAY IN TIME FOR THE NEW YEAR. EVEN THIS SHOT
OF COLD AIR APPEARS TO BE A GLANCING BLOW AND QUICKLY RETREATS TO
THE EAST.
THE COLD FRONT EXPECTED TO MOVE EAST INTO THE REGION ON SATURDAY
WILL HAVE LIMITED MOISTURE AT BEST AND MAY LIMIT THE AMOUNT OF
PRECIPITATION WE SEE WITH THE FEATURE.
DRIER AIR QUICKLY PUSHES INTO THE REGION FROM THE NORTHWEST IN
ADVANCE OF THE HIGH PRESSURE AND THIS SHOULD BRING A RETURN BACK TO
FAIR WEATHER TO THE REGION SUNDAY NIGHT INTO MONDAY. SOME LAKE
EFFECT SNOW SHOWER ACTIVITY IS POSSIBLE SATURDAY NIGHT INTO SUNDAY
IN NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA IN THE COLD AIR
ADVECTION.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
WARM FRONT LIFTING NORTH AT THIS TIME FORCING PRECIPITATION TO
MOVE NORTHEAST OF THE AREA AT THIS TIME. LITTLE TO NO
PRECIPITATION AT THIS TIME BEHIND THE FRONT AND NOT EXPECTING ANY
THING MORE THAN JUST SOME PATCHY DRIZZLE THROUGH MUCH OF THE DAY.
CEILINGS BEGIN TO LOWER FROM WEST TO EAST LATER IN THE DAY INTO
TONIGHT AS NEXT STORM SYSTEM APPROACHES FROM THE SOUTHWEST.
EXPECTING WINDS TO REMAIN LIGHT THROUGH THE DAY INTO TONIGHT OVER
MUCH OF THE AREA. HIGHEST WINDS WILL REMAIN CONFINED TO ERIE
PENNSYLVANIA NEAR THE LAKE.
.OUTLOOK...NON VFR POSSIBLE THROUGH THURSDAY.
&&
.MARINE...
GALE WATCHES HAVE ALREADY BEEN POSTED FOR WEDNESDAY AFTERNOON INTO
THURSDAY MORNING AS WINDS ON THE LAKE ARE EXPECTED TO INCREASE TO 35
TO 40 KNOTS. THIS IS IN RESPONSE TO STORM SYSTEM EXPECTED TO MOVE
NORTHEAST INTO THE FORECAST AREA AND AFFECT THE LAKE. GRADIENT WILL
BE QUITE STRONG AND THIS WILL CAUSE THE STRONGER WINDS ON THE LAKE.
AT THIS TIME...DO NOT EXPECT TO SEE STORM FORCE WINDS ON THE LAKE.
WINDS WILL GRADUALLY DIMINISH THURSDAY AFTERNOON AND THURSDAY NIGHT.
SOUTHERLY FLOW QUICKLY RETURNS BY THURSDAY NIGHT INTO FRIDAY AS HIGH
PRESSURE SCOOTS BY TO THE SOUTH OF THE AREA. THIS SHOULD SET UP SOME
WARM AIR ADVECTION OVER THE LAKE REDUCING THREAT OF HIGH WAVES BY
FRIDAY. NEXT STORM SYSTEM APPROACHES FROM THE WEST FORCING A COLD
FRONT ACROSS THE LAKE ON SATURDAY. WINDS AHEAD OF THE COLD FRONT
ARE EXPECTED TO INCREASE ON SATURDAY AND WILL LIKELY NEED SMALL
CRAFT ADVISORIES BY THEN.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY AFTERNOON
FOR LEZ061-142>149-162>169.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...LOMBARDY
AVIATION...LOMBARDY
MARINE...LOMBARDY
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
525 AM CST TUE DEC 23 2014
.AVIATION...
VFR CONDITIONS IN PLACE AT ALL THREE TAF SITES BUT EXPECT KLBB AND
KPVW TO BOUNCE AROUND BETWEEN VFR AND MVFR. LIGHT PRECIPITATION
MAY IMPACT KPVW AND KLBB OVER THE NEXT 3 HOURS BUT COVERAGE WILL
BE SO SPOTTY AND AMOUNTS SO LIGHT THAT GOING WITH ANY MENTION
WOULD NOT BE WARRANTED. WILL WATCH THROUGH THE MORNING AND AMEND
IF NECESSARY. WIND SPEED WILL CONTINUE TO RAMP UP THROUGH THE DAY
POSSIBLY REACHING THE 25 TO 30 KT SUSTAINED OUT OF THE NORTH WITH
HIGHER GUSTS. ADDITIONAL SHOWERS THIS AFTERNOON MAY IMPACT KCDS
BUT REMAIN EAST OF KLBB AND KPVW. THESE SHOULD BE HIGH ENOUGH TO
KEEP VFR CONDITIONS IN PLACE. AFTER SUNSET...WIND SPEEDS WILL
DECREASE AND VFR CONDITIONS WILL PREVAIL.
JORDAN
&&
.PREV DISCUSSION... /ISSUED 432 AM CST TUE DEC 23 2014/
SHORT TERM...
THE HEAVIEST BANDS OF PRECIPITATION HAVE MOVED SOUTH OF THE
AREA...FASTER THAN PRETTY MUCH EVERY OPERATIONAL MODEL RUN HAD IN
THE 12Z RUNS YESTERDAY AND THE 00Z RUNS TODAY. BEST MODELS HAVE
BEEN THE HRRR AND TTU-WRF WHICH BOTH SEEM TO BE FAIRLY CLOSE IN
THEIR FORECASTS COMPARED TO OBSERVED RADAR DATA. WV SATELLITE LOOP
SHOWS THE TROF AXIS IS ALMOST OVERHEAD AS IT DRIFTS OFF TO THE
EAST. THERE ALSO APPEARS TO BE TIGHTENING OF A CIRCULATION EAST OF
THE FOUR CORNERS AREA ALONG THE CO/NM BORDER THAT IS LIKELY HELPING
TO GENERATE SOME OF THE ADDITIONAL RETURNS ON RADAR ACROSS EASTERN
NEW MEXICO.
ANY PRECIPITATION ONGOING ACROSS THE AREA THIS MORNING WILL LIKELY
REMAIN A MIX OF RAIN/SNOW AS SURFACE TEMPERATURES ARE JUST NOW
STARTING TO FLIRT WITH FREEZING. THE TREND HAS BEEN FOR A GRADUAL
DECREASE IN AERIAL COVERAGE IN THE RETURNS BUT THERE COULD STILL BE
SOME MIXED PRECIP REACHING THE GROUND BY SUNRISE...MAINLY ACROSS THE
WESTERN AND SOUTHERN SOUTH PLAINS. THIS ACTIVITY SHOULD CONTINUE TO
DECREASE THROUGH THE MORNING RESULTING IN A BRIEF LULL LATE MORNING
THROUGH EARLY AFTERNOON. STILL IS SOME CONCERN ON HOW STRONG WIND
SPEEDS WILL BECOME THIS AFTERNOON AS THE GFS STILL WANTS TO RAMP
WINDS UP TO 25-35 MPH SUSTAINED ACROSS MOST OF THE CAPROCK. ALL
OTHER MODELS ABOUT 10 MPH LOWER SO WE OPTED TO KEEP WIND SPEEDS
BELOW WIND ADVISORY CRITERIA FOR OUR AREA THIS AFTERNOON. MODELS
CONTINUE TO HINT AT THE POSSIBILITY OF SOME WRAP AROUND
PRECIPITATION THIS AFTERNOON AS ANOTHER VORTMAX STRENGTHENS ON THE
BACK SIDE OF THE TROF AXIS. HIGHER RESOLUTION TTU-WRF AND HRRR ARE
HINTING THAT THESE WILL BE FAIRLY ISOLATED SHOWERS...NOT ANYTHING
THAT WILL BE ABLE TO PROVIDE WIDESPREAD PRECIPITATION AMOUNTS.
FORECAST SOUNDINGS SHOW THAT LAPSE RATES INCREASE A BIT AS THE
SECOND VORT MAX ROTATES AROUND THE BACKSIDE OF THE TROF AND THERE IS
JUST ENOUGH MOISTURE ALOFT TO GENERATE SOME PRECIPITATION. COVERAGE
IS LIMITED TO THE ROLLING PLAINS WHICH WILL BE CLOSER TO THE TROF
AXIS AND WHERE SLIGHTLY GREATER LAPSE RATES WILL BE IN PLACE ALOFT.
INCREASED POPS ACROSS THE ROLLING PLAINS TO ADD SLIGHT CHANCE OF
SHOWERS AS A RESULT. TEMPERATURES WILL CLIMB TO NEAR 50 ACROSS HERE
SO PROFILE WILL BE TOO WARM FOR ANY KIND OF A MIX OF PRECIPITATION.
CAPROCK WILL BE COOLER MAINLY DUE TO THE PRECIPITATION THAT HAS
FALLEN...CLOUD COVER...AND THE BRISK NORTH WIND.
ANY PRECIPITATION WILL COME TO AN END AFTER SUNSET AS THE TROF AXIS
SLIDES OFF TO THE EAST AND AS LAPSE RATES START TO DECREASE.
TEMPERATURES TONIGHT WILL BE PRETTY CHILLY BUT NOT AS COLD AS IT
COULD BE AS WIND SPEEDS WILL REMAIN UP DUE TO THE PRESSURE GRADIENT
REMAINING SOMEWHAT TIGHT. STILL WILL SEE READINGS ACROSS THE
NORTHWESTERN SOUTH PLAINS MAKE IT INTO THE UPPER TEENS WITH THE
ROLLING PLAINS HOVERING AROUND FREEZING.
JORDAN
LONG TERM...
THE FINAL DAYS OF 2014 LOOK TO CLOSE OUT ON A CHILLY NOTE AS A
LARGE SCALE PATTERN CHANGE UNFOLDS AND DIRECTS ARCTIC AIR INTO
MUCH OF MIDDLE CONUS INCLUDING WEST TX. THIS TRANSITION WILL
ALREADY BE IN FULL SWING FRIDAY INTO THE WEEKEND...BUT UNTIL THEN
A WARMING TREND IN STORE UNDERNEATH RISING HEIGHTS BEHIND TODAY/S
UPPER TROUGH. CHRISTMAS DAY IS STILL SHAPING UP QUITE MILD AS LEE
TROUGHING DEEPENS TO OUR WEST AND SUBJECTS MUCH OF THE CWA TO AN
ENHANCED BAND OF SWLY GRADIENT WINDS. EDGED MAX TEMPS UP CLOSER TO
THE ECMWF MOS AS MAV AND MET APPEAR SUSPICIOUSLY COOL FOR THIS
DEEP SWLY FLOW REGIME.
ECM AND GFS ARE IN GOOD ACCORD WITH A STRONG COLD FROPA BY FRI AS
A PIECE OF A TROUGH IN THE FOUR CORNERS LIFTS NORTHEAST. WHERE
THESE MODELS DIFFER IS HOW MUCH ENERGY LINGERS BACK IN THE MAIN
TROUGH AXIS TO OUR WEST FOR FRI NITE INTO THE WEEKEND. THE DEEPER
ECM ADVECTS SUBTROPICAL MOISTURE NEWD ATOP OUR COOL DOME AND AS
SUCH IS EAGER TO GENERATE BOTH LIFT AND QPF ALONG THE ELEVATED
FRONTAL SURFACE. THE GFS IS DRIER AND ABOUT 40 METERS HIGHER WITH
500MB HEIGHTS COMPARED TO ITS FIERCEST COMPETITOR...BUT STILL
GARNERS LIGHT QPF ON SAT WITH ITS DAMPENED TROUGH. EARLIER
SUPERBLEND POPS WERE MASSAGED A BIT TO BETTER WEIGHT THE LATEST
00Z GUIDANCE...BUT A VERY LIGHT RAIN/SNOW EVENT REMAINS IN THE
CARDS FOR FRI NITE-SAT.
BY LATE WEEKEND AND MONDAY...THE STAGE LOOKS PRIMED FOR AN ARCTIC
DUMP AS DEEP NLY FLOW ENSUES FROM THE CANADIAN ROCKIES SOUTH TO
THE CENTRAL HIGH PLAINS. MODELS AND ENSEMBLES ARE NOT DEVIATING MUCH
WITH THIS PATTERN CHANGE...SO CONFIDENCE IS MOUNTING THAT OUR MILD
DECEMBER MAY END ON A CHILLY NOTE. IF THE ARCTIC AIR IS AS STRONG
AS CURRENTLY PROGGED...WE WOULD NOT BE SURPRISED TO AT LEAST SEE
FREEZING DRIZZLE AT SOME POINT EARLY NEXT WEEK AS THESE ARCTIC
AIRMASSES CAN BE NOTORIOUS FOR SUSTAINING LOW CLOUDS ALONG THE
SHARP FRONTAL INVERSION. TEMPS WERE EDGED DOWN IN LINE WITH
CONSALL...BUT IT/S TOO SOON TO JUMP ON ANY POPS EVEN WITH A
DEEPENING TROUGH PROGGED TO OUR WEST BY MON/TUE.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 38 18 46 24 63 / 20 0 0 0 0
TULIA 40 22 48 27 63 / 10 0 0 0 0
PLAINVIEW 41 25 48 28 63 / 10 0 0 0 0
LEVELLAND 41 24 47 27 64 / 20 0 0 0 0
LUBBOCK 42 25 47 29 64 / 10 0 0 0 0
DENVER CITY 42 24 48 28 65 / 20 0 0 0 0
BROWNFIELD 43 25 48 28 64 / 20 0 0 0 0
CHILDRESS 47 31 50 31 67 / 20 10 0 0 0
SPUR 47 28 50 30 65 / 10 0 0 0 0
ASPERMONT 49 30 51 31 66 / 20 10 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
14/93/14
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
432 AM CST TUE DEC 23 2014
.SHORT TERM...
THE HEAVIEST BANDS OF PRECIPITATION HAVE MOVED SOUTH OF THE
AREA...FASTER THAN PRETTY MUCH EVERY OPERATIONAL MODEL RUN HAD IN
THE 12Z RUNS YESTERDAY AND THE 00Z RUNS TODAY. BEST MODELS HAVE
BEEN THE HRRR AND TTU-WRF WHICH BOTH SEEM TO BE FAIRLY CLOSE IN
THEIR FORECASTS COMPARED TO OBSERVED RADAR DATA. WV SATELLITE LOOP
SHOWS THE TROF AXIS IS ALMOST OVERHEAD AS IT DRIFTS OFF TO THE
EAST. THERE ALSO APPEARS TO BE TIGHTENING OF A CIRCULATION EAST OF
THE FOUR CORNERS AREA ALONG THE CO/NM BORDER THAT IS LIKELY HELPING
TO GENERATE SOME OF THE ADDITIONAL RETURNS ON RADAR ACROSS EASTERN
NEW MEXICO.
ANY PRECIPITATION ONGOING ACROSS THE AREA THIS MORNING WILL LIKELY
REMAIN A MIX OF RAIN/SNOW AS SURFACE TEMPERATURES ARE JUST NOW
STARTING TO FLIRT WITH FREEZING. THE TREND HAS BEEN FOR A GRADUAL
DECREASE IN AERIAL COVERAGE IN THE RETURNS BUT THERE COULD STILL BE
SOME MIXED PRECIP REACHING THE GROUND BY SUNRISE...MAINLY ACROSS THE
WESTERN AND SOUTHERN SOUTH PLAINS. THIS ACTIVITY SHOULD CONTINUE TO
DECREASE THROUGH THE MORNING RESULTING IN A BRIEF LULL LATE MORNING
THROUGH EARLY AFTERNOON. STILL IS SOME CONCERN ON HOW STRONG WIND
SPEEDS WILL BECOME THIS AFTERNOON AS THE GFS STILL WANTS TO RAMP
WINDS UP TO 25-35 MPH SUSTAINED ACROSS MOST OF THE CAPROCK. ALL
OTHER MODELS ABOUT 10 MPH LOWER SO WE OPTED TO KEEP WIND SPEEDS
BELOW WIND ADVISORY CRITERIA FOR OUR AREA THIS AFTERNOON. MODELS
CONTINUE TO HINT AT THE POSSIBILITY OF SOME WRAP AROUND
PRECIPITATION THIS AFTERNOON AS ANOTHER VORTMAX STRENGTHENS ON THE
BACK SIDE OF THE TROF AXIS. HIGHER RESOLUTION TTU-WRF AND HRRR ARE
HINTING THAT THESE WILL BE FAIRLY ISOLATED SHOWERS...NOT ANYTHING
THAT WILL BE ABLE TO PROVIDE WIDESPREAD PRECIPITATION AMOUNTS.
FORECAST SOUNDINGS SHOW THAT LAPSE RATES INCREASE A BIT AS THE
SECOND VORT MAX ROTATES AROUND THE BACKSIDE OF THE TROF AND THERE IS
JUST ENOUGH MOISTURE ALOFT TO GENERATE SOME PRECIPITATION. COVERAGE
IS LIMITED TO THE ROLLING PLAINS WHICH WILL BE CLOSER TO THE TROF
AXIS AND WHERE SLIGHTLY GREATER LAPSE RATES WILL BE IN PLACE ALOFT.
INCREASED POPS ACROSS THE ROLLING PLAINS TO ADD SLIGHT CHANCE OF
SHOWERS AS A RESULT. TEMPERATURES WILL CLIMB TO NEAR 50 ACROSS HERE
SO PROFILE WILL BE TOO WARM FOR ANY KIND OF A MIX OF PRECIPITATION.
CAPROCK WILL BE COOLER MAINLY DUE TO THE PRECIPITATION THAT HAS
FALLEN...CLOUD COVER...AND THE BRISK NORTH WIND.
ANY PRECIPITATION WILL COME TO AN END AFTER SUNSET AS THE TROF AXIS
SLIDES OFF TO THE EAST AND AS LAPSE RATES START TO DECREASE.
TEMPERATURES TONIGHT WILL BE PRETTY CHILLY BUT NOT AS COLD AS IT
COULD BE AS WIND SPEEDS WILL REMAIN UP DUE TO THE PRESSURE GRADIENT
REMAINING SOMEWHAT TIGHT. STILL WILL SEE READINGS ACROSS THE
NORTHWESTERN SOUTH PLAINS MAKE IT INTO THE UPPER TEENS WITH THE
ROLLING PLAINS HOVERING AROUND FREEZING.
JORDAN
&&
.LONG TERM...
THE FINAL DAYS OF 2014 LOOK TO CLOSE OUT ON A CHILLY NOTE AS A
LARGE SCALE PATTERN CHANGE UNFOLDS AND DIRECTS ARCTIC AIR INTO
MUCH OF MIDDLE CONUS INCLUDING WEST TX. THIS TRANSITION WILL
ALREADY BE IN FULL SWING FRIDAY INTO THE WEEKEND...BUT UNTIL THEN
A WARMING TREND IN STORE UNDERNEATH RISING HEIGHTS BEHIND TODAY/S
UPPER TROUGH. CHRISTMAS DAY IS STILL SHAPING UP QUITE MILD AS LEE
TROUGHING DEEPENS TO OUR WEST AND SUBJECTS MUCH OF THE CWA TO AN
ENHANCED BAND OF SWLY GRADIENT WINDS. EDGED MAX TEMPS UP CLOSER TO
THE ECMWF MOS AS MAV AND MET APPEAR SUSPICIOUSLY COOL FOR THIS
DEEP SWLY FLOW REGIME.
ECM AND GFS ARE IN GOOD ACCORD WITH A STRONG COLD FROPA BY FRI AS
A PIECE OF A TROUGH IN THE FOUR CORNERS LIFTS NORTHEAST. WHERE
THESE MODELS DIFFER IS HOW MUCH ENERGY LINGERS BACK IN THE MAIN
TROUGH AXIS TO OUR WEST FOR FRI NITE INTO THE WEEKEND. THE DEEPER
ECM ADVECTS SUBTROPICAL MOISTURE NEWD ATOP OUR COOL DOME AND AS
SUCH IS EAGER TO GENERATE BOTH LIFT AND QPF ALONG THE ELEVATED
FRONTAL SURFACE. THE GFS IS DRIER AND ABOUT 40 METERS HIGHER WITH
500MB HEIGHTS COMPARED TO ITS FIERCEST COMPETITOR...BUT STILL
GARNERS LIGHT QPF ON SAT WITH ITS DAMPENED TROUGH. EARLIER
SUPERBLEND POPS WERE MASSAGED A BIT TO BETTER WEIGHT THE LATEST
00Z GUIDANCE...BUT A VERY LIGHT RAIN/SNOW EVENT REMAINS IN THE
CARDS FOR FRI NITE-SAT.
BY LATE WEEKEND AND MONDAY...THE STAGE LOOKS PRIMED FOR AN ARCTIC
DUMP AS DEEP NLY FLOW ENSUES FROM THE CANADIAN ROCKIES SOUTH TO
THE CENTRAL HIGH PLAINS. MODELS AND ENSEMBLES ARE NOT DEVIATING MUCH
WITH THIS PATTERN CHANGE...SO CONFIDENCE IS MOUNTING THAT OUR MILD
DECEMBER MAY END ON A CHILLY NOTE. IF THE ARCTIC AIR IS AS STRONG
AS CURRENTLY PROGGED...WE WOULD NOT BE SURPRISED TO AT LEAST SEE
FREEZING DRIZZLE AT SOME POINT EARLY NEXT WEEK AS THESE ARCTIC
AIRMASSES CAN BE NOTORIOUS FOR SUSTAINING LOW CLOUDS ALONG THE
SHARP FRONTAL INVERSION. TEMPS WERE EDGED DOWN IN LINE WITH
CONSALL...BUT IT/S TOO SOON TO JUMP ON ANY POPS EVEN WITH A
DEEPENING TROUGH PROGGED TO OUR WEST BY MON/TUE.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 38 18 46 24 63 / 20 0 0 0 0
TULIA 40 22 48 27 63 / 10 0 0 0 0
PLAINVIEW 41 25 48 28 63 / 10 0 0 0 0
LEVELLAND 41 24 47 27 64 / 20 0 0 0 0
LUBBOCK 42 25 47 29 64 / 10 0 0 0 0
DENVER CITY 42 24 48 28 65 / 20 0 0 0 0
BROWNFIELD 43 25 48 28 64 / 20 0 0 0 0
CHILDRESS 47 31 50 31 67 / 20 10 0 0 0
SPUR 47 28 50 30 65 / 10 0 0 0 0
ASPERMONT 49 30 51 31 66 / 20 10 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
14/93
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
944 AM MST TUE DEC 23 2014
.SYNOPSIS...
HIGH PRESSURE OFF THE WEST COAST WILL RESULT IN NEAR NORMAL
TEMPERATURES WITH VARYING AMOUNTS OF HIGH CLOUDS THROUGH THE MIDDLE
OF THE WEEK. BY THURSDAY...THE STORM PATTERN WILL BECOME MORE ACTIVE
ACROSS THE WEST COAST AS A SERIES OF SHORTWAVES SWEEP THROUGH THE
REGION. COOLER TEMPERATURES AND INCREASED CLOUDINESS ARE EXPECTED
THURSDAY INTO FRIDAY. DRY...AND POTENTIALLY MUCH COOLER...WEATHER IS
EXPECTED BY THE COMING WEEKEND.
&&
.DISCUSSION...
VISIBLE SAT IMAGERY CURRENTLY SHOWS GENERALLY CLEAR SKIES OVER
ENTIRE FORECAST AREA...THE RESULT OF SUBSIDENCE ASSOCIATED WITH
UPPER LEVEL RIDGE BUILDING INTO THE SOUTHWEST. MODEL SOUNDINGS
INDICATE CONSIDERABLE DRYING OF THE AIRMASS OVER THE REGION DURING
THE LAST 24-HOURS...WITH PWAT DROPPING TO AROUND ONE QUARTER OF AN
INCH. WIND PROFILE FROM THE SFC TO ABOVE 3H REMAINS NORTH TO
NORTHEAST...KEEPING COOLER AIR OVER MUCH THE REGION.
AS INDICATED IN EARLIER DISCUSSION...TIGHTENING LOW LEVEL SURFACE
GRADIENT WILL RESULT IN PERIODS OF BREEZY TO WINDY CONDITIONS...
PARTICULARLY DOWN THE COLORADO RIVER VALLEY AND OVER SOUTHERN GILA
COUNTY. REAL-TIME MESOANALYSIS DATA INDICATES SOME INCREASING WINDS
ALREADY IN THESE AREAS. COLD AIR BOUNDARY OVER SOUTHERN GILA COUNTY
HAS BEEN NUDGING TO THE SOUTHWEST...THOUGH NOTICED THE HRRR DOESNT
PUSH THIS BOUNDARY MUCH FURTHER SOUTH. EXPECT ONLY REAL AFFECT THEN
WILL BE THE STRONGER WINDS ALREADY MENTIONED.
TEMPERATURES ACROSS THE REGION THIS MORNING WERE GENERALLY WARMER
THAN YESTERDAY AT THIS TIME...PARTICULARLY OVER SOUTHWEST ARIZONA
AND SOUTHEAST CALIFORNIA...WHERE OBSERVATIONS WERE 10 DEGREES OR
MORE WARMER THAN 24-HOURS AGO. HAD TO MAKE SOME ADJUSTMENTS IN OUR
MAX TEMPERATURE FORECASTS FOR TODAY...PRIMARILY IN THE WESTERN THIRD
OF THE FORECAST AREA...SO GRIDS WOULD BETTER TRACK CURRENT TEMPS AND
EXPECTED TRENDS. DEWPOINT TEMPERATURES FIRST PERIOD WERE ALSO
TWEAKED. THE REMAINDER OF OUR FORECAST PACKAGE CURRENTLY IS ON
TRACK.
&&
.PREV DISCUSSION...
ISSUED AT 455 AM MST TUE DEC 23 2014
BROAD TROUGHING COVERS MUCH OF THE CONUS THE MORNING...WITH HIGH
AMPLITUDE RIDGING EXPANDING ACROSS THE NORTHEASTERN PACIFIC FROM OFF
THE BAJA/SOCAL COAST UP THROUGH SOUTHERN BRITISH COLUMBIA. EARLY AM
SFC ANALYSIS PLOTS A STRENGTHENING SFC HIGH...AROUND 1032MB...OVER ID
WITH TIGHTENED NORTHERLY SFC PRESSURE GRADIENTS ALREADY DROPPING INTO
NORTHERN AZ AND THE CO RIVER VALLEY. NORTHERLY WINDS BEGAN LAST
EVENING AT BLYTHE AND SITES UPSTREAM AND WILL CONTINUE FOR MUCH OF
THE DAY AS THE SURFACE HIGH STRENGTHENS AND SLIDES FURTHER INTO THE
GREAT BASIN. MEANWHILE TO OUR NORTHEAST AND EAST...STRONG 500MB/300MB
JET ENERGY ALONG A SHORTWAVE IMPULSE IS AIDING PRECIP ACTIVITY ACROSS
CO AND NM. MUCH AZ REMAINS UNDER PARTIAL INFLUENCE OF THE UPPER
RIDGE...WITH SUBSIDENT FLOW PRODUCING CLEAR MORNING SKIES. EARLY AM
TEMPERATURES ARE FAIRLY MILD ALONG THE CO RIVER VALLEY...THANKS TO
THE OVERNIGHT WINDS...WITH LOCATIONS LIKE DESERT CENTER AND BLYTHE
CA STILL REPORTING TEMPERATURES IN THE 60S.
TODAY AND WEDNESDAY...
STRONG LOW LEVEL PRESSURE GRADIENTS WILL PERSIST GUSTY NORTH-
NORTHEAST WINDS ACROSS MOST OF OUR FORECAST AREA...STRONGEST DOWN THE
COLORADO RIVER VALLEY AND OVER SOUTHERN GILA COUNTY WHERE RIDGE TOP
WINDS COULD BRIEFLY APPROACH 40 MPH. CO RIVER VALLEY WINDS SHOULD
INCREASE A FEW HOURS AFTER SUNRISE WITH SUDDEN GUSTS TO 30
MPH...SIMILARLY IN THE MOUNTAIN VALLEYS OF SOUTHERN GILA COUNTY. THE
REMAINDER OF THE LOWER DESERTS INCLUDING PHOENIX ARE FORECAST IN THE
BREEZY CATEGORY...10 TO 20 MPH. TRAILING SHORTWAVE ENERGY OFF THE
BROAD CONUS TROUGH WILL FORCE A BACKDOOR COLD FRONT TO THE SOUTHWEST
THROUGH AZ TODAY BEFORE THE DISTURBANCE BOTTOMS OUT OVER WEST TEXAS
BY LATER THIS AM. THE FRONT WILL BE DRY...BUT THE INTRUSION OF DRIER
COLD AIR WILL OFFSET ANY WARMING EXPECTED OVER OUR SOUTH-CENTRAL AZ
ZONES...WITH JUST A FEW DEGREES OF COOLING EXPECTED ACROSS SOUTHEAST
CALIFORNIA AND THE LOWER CO RIVER VALLEY. WINDS WILL ABATE BY
WEDNESDAY MORNING AND COOLER DAYTIME TEMPS BACK INTO THE 60S WILL
PREVAIL ACROSS THE LOWER DESERTS.
THURSDAY THROUGH INTO EARLY NEXT WEEK...
ANOTHER PASSING COOL FRONT AND SWIFT MOVING PACIFIC TROUGH WILL SWEEP
INTO THE REGION FROM THE NORTHWEST THURSDAY. LOWERING HEIGHTS AND
THICKNESSES COULD DRAW SOME MOISTURE IN FROM OFF THE PACIFIC...BUT
FCST PWATS HAVE BEEN DRAWN DOWN AROUND 0.50 OR LESS. ELEVATED WEST-
SOUTHWEST DAYTIME BREEZES AND INCREASING CLOUDS ARE EXPECTED FORECAST
AREA WIDE. THE REMOTE CHANCE FOR LIGHT SHOWER ACTIVITY STILL LINGERS
THE EASTERN AZ HIGHER TERRAIN...INCLUDING THE FOOTHILLS ACROSS
EASTERN PINAL AND SOUTHERN GILA COUNTY. UPPER TROUGH WILL LINGER OVER
THE FOUR CORNERS FRIDAY INTO SATURDAY LEAVING TEMPERATURES FORECAST
BELOW NORMAL...FOR A CHANGE...AS ADDITIONAL TROUGH ENERGY LOADS
UPSTREAM OVER THE PACIFIC NW.
BROAD TROUGHING WILL ENCOMPASS MUCH OF THE CONUS BY SATURDAY AND INTO
NEXT WEEK AS THE HIGHLY AMPLIFIED ROSSBY WAVE PATTERN SENDS RIDGING
WELL UP INTO ALASKA. PACIFIC NW TROUGHING WILL EXPAND ACROSS THE
INTERIOR WEST EARLY NEXT WEEK AIDED BY A VERY COLD AIR AND A
DISPLACED SFC HIGH FROM ALASKA AND NORTHERN CANADA. THIS POTENTLY
COLDER SYSTEM STILL LOOKS TO BE ON THE DRY SIDE. CPC MEDIUM RANGE
OUTLOOK AND WPC EXTENDED MODEL DISCUSSIONS ALL GNLY AGREE ON THE
POTENTIAL FOR BELOW NORMAL TEMPERATURES WITH THE CURRENT CHOICE OF
MODEL SOLNS FALLING MOSTLY TO THE LAST FEW RUNS OF ECMWF AND ITS
ENSEMBLES. BLEND OF THE BEST PERFORMING AND CONSENSUS TEMP
GUIDANCE...WITH A BIT MORE WEIGHT TOWARDS THE ECBC SOLN...RESULTS IN
COLD MORNINGS WITH UPPER 20 TO LOW 40 DEGREE READINGS POSSIBLE OVER
THE LOWER DESERTS. TRENDED TEMPERATURES IN A COOLER DIRECTION FOR
NOW AND WILL CONTINUE TO MONITOR THE POTENTIAL FOR NEAR FREEZING OR
FREEZING TEMPERATURES TO OPEN THE 2015 NEW YEAR.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
A TIGHTENING PRESSURE GRADIENT WILL EVENTUALLY ALLOW SFC WINDS TO
MAINTAIN A PREVAILING N/NE TRAJECTORY BY LATER THIS
MORNING...HOWEVER PERIODS OF VARIABLE OR UNUSUAL LIGHT SW COMPONENT
WILL BE COMMON AT THE IMMEDIATE SFC THROUGH THE PHOENIX AREA THIS
MORNING...WITH NE WINDS 1-2K FT ABV THE SFC. A FEW GUSTS OVER 15KT
MAY BE POSSIBLE DURING THE LATE MORNING...HOWEVER A WEAKENING
GRADIENT BY LATE AFTERNOON WILL FORCE A LIGHTER E/NE DRAINAGE WIND.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA...INCLUDING KIPL AND
KBLH...
A PERIOD OF GUSTY NORTH WINDS LATER THIS MORNING (PARTICULARLY AT
KBLH) WILL BE THE PRIMARY AVIATION CONCERN THROUGH THE NEXT 24
HOURS. WHILE MARGINAL LLWS CONDITIONS MAY BRIEFLY OCCUR THIS
MORNING...VERTICAL MIXING SHOULD ALLOW GUSTS TO REACH THE SFC FAIRLY
RAPIDLY. HOWEVER...THE PRESSURE GRADIENT MAY BEGIN TO WEAKEN
SUBSTANTIALLY THIS AFTERNOON...AND UNCERTAINTY EXISTS AS TO THE
DURATION OF STRONGER GUSTS OVER 25KT. CERTAINLY BY THIS
EVENING...SUSTAINED SFC WINDS WILL FALL BELOW 12KT LEADING TO LITTLE
TO NO IMPACTS HEADING INTO WEDNESDAY MORNING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
A SERIES OF WEATHER DISTURBANCES MOVING THROUGH THE GREAT BASIN WILL
ALLOW COOLER AIR AND OCCASIONAL BREEZY CONDITIONS TO FILTER INTO THE
DISTRICT THROUGH THE LATTER HALF OF THE WEEK AND WEEKEND. WHILE A
FEW LIGHT SHOWERS MAY BE POSSIBLE OVER PARTS OF EASTERN ARIZONA
FRIDAY...THE MAJORITY OF THE TIME WILL BE DRY. GIVEN THE COOLER
WEATHER...AFTERNOON HUMIDITY LEVELS WILL ONLY FALL INTO A 20 TO 35
PERCENT RANGE WITH GOOD TO EXCELLENT OVERNIGHT RECOVERY.
OVERALL...THE FIRE DANGER WILL BE MINIMAL DURING THIS PERIOD.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...MCLANE/NOLTE
AVIATION....MO
FIRE WEATHER...MO
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
200 PM PST TUE DEC 23 2014
.SYNOPSIS...
WEAKENING UPPER LEVEL HIGH PRESSURE WILL ALLOW A SLIGHT COOLING ON
WEDNESDAY. SURFACE HIGH PRESSURE OVER NEVADA AND UTAH WILL BRING
LOCALLY STRONG...GUSTY NORTHEAST WINDS TO THE COASTAL SLOPES OF THE
MOUNTAINS AND ADJACENT FOOTHILL AREAS...GRADUALLY DECREASING THIS
AFTERNOON THROUGH LATE TONIGHT. A LOW PRESSURE SYSTEM PASSING BY TO
THE NORTH WILL RESULT IN COOLING AND STRONG GUSTY WEST WINDS FOR THE
MOUNTAINS AND DESERTS LATE WEDNESDAY NIGHT INTO CHRISTMAS DAY...WITH
A SLIGHT CHANCE OF SHOWERS ALONG AND WEST OF THE MOUNTAINS.
CONTINUED COOL CONDITIONS WITH PERIODS OF STRONG GUSTY NORTHEAST
WINDS FOR FRIDAY AND SATURDAY.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.SHORT TERM (TODAY THROUGH CHRISTMAS)...
SURFACE HIGH PRESSURE OVER THE GREAT BASIN CONTINUES TO BRING
LOCALLY STRONG GUSTY SANTA ANA WINDS TO THE COASTAL SLOPES OF THE
MOUNTAINS AND ADJACENT FOOTHILL AREAS. THE WINDS ARE EXPECTED TO
GRADUALLY SUBSIDE THIS AFTERNOON THROUGH LATE TONIGHT.
A FEW DEGREES OF COOLING IS EXPECTED ALONG AND WEST OF THE MOUNTAINS
FOR WEDNESDAY AS OFFSHORE FLOW WEAKENS AND HIGH PRESSURE ALOFT
WEAKENS. BUFKIT SHOWS LESS MARINE LAYER TONIGHT COMPARED TO THIS
MORNING...BUT ALONG WITH THE HRRR AND THE WRFEMS...AND SUPPORT FROM
THE VISIBLE SATELLITE IMAGERY...THERE COULD BE SOME PATCHY DENSE
FOG. THIS HAS BEEN ADDED TO THE FORECASTS FOR THIS AFTERNOON THROUGH
WEDNESDAY MORNING.
FOR WEDNESDAY NIGHT INTO CHRISTMAS DAY...A TROUGH WILL BRING A
RETURN OF ONSHORE FLOW WITH COOLING AND STRONG GUSTY WEST WINDS FOR
THE MOUNTAINS AND DESERTS FOR LATE WEDNESDAY NIGHT INTO CHRISTMAS
MORNING. A SLIGHT CHANCE OF MAINLY LIGHT SHOWERS ALONG AND WEST OF
THE MOUNTAINS FOR LATE WEDNESDAY NIGHT INTO CHRISTMAS MORNING IS
EXPECTED. A DUSTING OF SNOWFALL IS POSSIBLE IN THE MOUNTAINS...
MAINLY ABOVE 6000 TO 6500 FEET.
&&
.LONG TERM (FRIDAY THROUGH MONDAY)...
CONTINUE COOL FRIDAY THROUGH MONDAY WITH HIGH TEMPERATURES ONLY
AROUND 5 DEGREES BELOW AVERAGE. SURFACE HIGH PRESSURE OVER THE GREAT
BASIN WILL DEVELOP ONCE AGAIN FOR PERIODS OF STRONG GUSTY NORTHEAST
WINDS FRIDAY AND SATURDAY. ANOTHER COLD LOW PRESSURE SYSTEM MOVING
SOUTHWARD THROUGH THE WESTERN STATES FOR SUNDAY THROUGH TUESDAY...AS
SEEN IN THE GFS ENSEMBLE MEAN...COULD BRING A RETURN OF ONSHORE FLOW
EARLY MONDAY WITH A SLIGHT CHANCE OF SHOWERS FOLLOWED BY GUSTY NORTH
TO NORTHEAST WINDS FOR TUESDAY AND WEDNESDAY...AND CONTINUED RATHER
COOL CONDITIONS.
&&
.AVIATION...
232130Z...SKC CONDS WITH P6SM WILL CONTINUE THROUGH WEDNESDAY WITH
THE EXCEPTION OF PATCHY LOW CLOUDS AND FOG FORMING ON THE IMMEDIATE
COASTLINE TONIGHT.
GUSTY NE WINDS WILL CONTINUE THROUGH TONIGHT ALONG THE COASTAL
FOOTHILLS OF SAN DIEGO COUNTY...NORTHWESTERN PORTIONS OF THE INLAND
EMPIRE...AND THE SANTA ANA MOUNTAINS. AREAS OF LLWS AND MOD-STG
UDDFS POSSIBLE OVER AND SW OF THE MTNS...INCLUDING VCNTY KONT AND
KSNA. NE-E WINDS WILL WEAKEN SLIGHTLY WEAKEN BY WEDNESDAY MORNING.
&&
.MARINE...
100 PM...BRIEF PATCHY DENSE FOG MAY OCCUR THIS AFTERNOON THROUGH
TONIGHT OVER THE COASTAL WATERS. A TROUGH OF LOW PRESSURE MOVING
INLAND WED NIGHT INTO THU WILL BRING GUSTY WEST-NORTHWEST WINDS TO
THE COASTAL WATERS. WIND GUSTS OF 20-25 KT ARE LIKELY OVER THE
COASTAL WATERS WED NIGHT INTO THU AFTERNOON. WINDS WILL WEAKEN THU
NIGHT. NO HAZARDOUS MARINE WEATHER FRI-SAT.
&&
.FIRE WEATHER...
SURFACE HIGH PRESSURE OVER THE GREAT BASIN WILL WEAKEN THROUGH
WEDNESDAY. THIS FEATURE SHALL CONTINUE THE WEAK TO MODERATE OFFSHORE
FLOW AND ABOVE NORMAL HIGH TEMPERATURES WEST OF THE MOUNTAINS. FROM
WEDNESDAY NIGHT INTO THURSDAY MORNING A TROUGH OF LOW PRESSURE WILL
BRING ONSHORE WINDS OF MODERATE STRENGTH...INCREASING RH...LOWER
HIGH TEMPS...AND A SLIGHT CHANCE OF LIGHT RAIN SHOWERS OVER AND WEST
OF THE MOUNTAINS. OFFSHORE FLOW WILL RETURN FRIDAY INTO SATURDAY
WITH TEMPERATURES REMAINING AT OR BELOW NORMAL.
&&
.SKYWARN...
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...WIND ADVISORY UNTIL 6 PM PST THIS EVENING FOR THE ORANGE COUNTY
COASTAL AREAS...RIVERSIDE COUNTY MOUNTAINS...SAN BERNARDINO
COUNTY MOUNTAINS...SAN BERNARDINO AND RIVERSIDE COUNTY
VALLEYS-THE INLAND EMPIRE...SAN DIEGO COUNTY MOUNTAINS...
SAN DIEGO COUNTY VALLEYS...SANTA ANA MOUNTAINS AND
FOOTHILLS.
PZ...NONE.
&&
$$
PUBLIC...SMALL
FIRE WEATHER...JT
AVIATION/MARINE...JT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1058 AM MST TUE DEC 23 2014
.UPDATE...
ISSUED AT 1055 AM MST TUE DEC 23 2014
UPDATED FOR EXPIRATION OF WINTER STORM WARNING FOR N EL PASO...AND
EXPIRATION OF HIGH WIND WARNING FOR S EL PASO AND PUEBLO COUNTIES.
STRONG NORTHERLY WINDS CONTINUE ACROSS THE PLAINS...BUT ARE
EXPECTED TO WANE THROUGH THE AFTN FROM WEST TO EAST. MOORE
UPDATE ISSUED AT 933 AM MST TUE DEC 23 2014
QUICK UPDATE TO ADJUST CLOUD COVER AND POPS FROM THE EASTERN MTS
WESTWARD. ONGOING FORECAST GRIDS FOR THE E PLAINS LOOK GOOD AT
THIS TIME. MOORE
UPDATE ISSUED AT 713 AM MST TUE DEC 23 2014
WINDS CONTINUE TO SLOWLY INCREASE ACROSS THE EASTERN PLAINS WITH
HIGHEST RECORDED GUST IN PAST HOUR OF 46KTS AT SPD. WINDS AND
SNOWFALL LAGGING ACROSS THE PALMER DVD...THOUGH STILL SEEING SOME
ECHOES ACROSS DOUGLAS AND LINCOLN COUNTIES...WHICH COULD POSE
TRAVEL IMPACTS ACROSS PORTIONS OF NORTHEASTERN EL PASO COUNTY AND
THE PALMER DVD. WITH THAT SAID...WILL KEEP WINTER STORM WARNING
ONGOING FOR NORTHERN EL PASO COUNTY FOR NOW...DUE TO POSSIBLE
VISIBILITY REDUCTIONS AND TRAVEL IMPACTS IN LIGHT SNOW AND BLOWING
SNOW...AS ANY ADDITIONAL ACCUMULATIONS ARE EXPECTED TO LIGHT AND
SPOTTY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM MST TUE DEC 23 2014
...STRONG WINDS ACROSS EASTERN COLORADO TODAY...
NO BIG CHANGES TO CURRENT FORECAST WITH STRONG NORTHERLY WINDS
GUSTING TO BETWEEN 50 AND 60 MPH EXPECTED ACROSS MUCH OF EASTERN
COLORADO LATER THIS MORNING AND AFTERNOON...WITH A STRONG SFC-H7
GRADIENT SETTING UP ACROSS THE PLAINS AS UPPER JET CORE ACROSS
WESTERN COLORADO THIS MORNING TRANSLATES EAST THROUGH THE AFTERNOON.
AS OF 3 AM...STARTING TO SEE GUSTY NORTH TO NORTHWEST WINDS OF 20 TO
40 MPH ACROSS NORTHEASTERN COLORADO REACHING AS FAR SOUTH AS LIMON
AND BURLINGTON...WITH BEST 3HRLY SFC PRESSURE RISES OF 2-3 MBS STILL
ACROSS NORTHEASTERN COLORADO AND SOUTHWESTERN NEBRASKA. WITH THAT
SAID...SHOULD SEE STRONG NORTHERLY WINDS HITTING THE PALMER DVD
WITHIN THE NEXT HOUR OR SO...WHICH WILL CONTINUE TO STRENGTHEN AS
SFC PRESSURE GRADIENT TIGHTENS AND CONTINUES SOUTH AND EAST ACROSS
THE REST OF THE SOUTHEAST PLAINS THROUGH THE REST OF THE MORNING.
LATEST HIGHER RESOLUTION HRRR AND RAP MODELS KEEP MOST OF
PRECIPITATION OUT ACROSS THE FAR SE PLAINS AND ALONG THE SOUTHERN
COLORADO AND NEW MEXICO BORDER TODAY...WITH ONE BAND MOVING SOUTH
AND EAST OF BURLINGTON ATTM. HOWEVER...LATEST RADAR AND SATELLITE
INDICATING SOME ENHANCED ECHOES NORTHEAST OF EL PASO AND LINCOLN
COUNTIES...AND WITH THE STRONG NORTHERLY WINDS HITTING THE PALMER
DIVIDE...STILL SHOULD SEE AN ENHANCED PERIOD OF WIND DRIVEN SNOW
ACROSS NORTHERN PORTIONS OF EL PASO COUNTY THROUGH THE MORNING
DRIVE...WITH A FEW INCHES OF ADDITIONAL ACCUMULATIONS POSSIBLE.
THE MAIN ISSUE...HOWEVER...WILL BE EXPECTED POOR VISIBILITIES IN
BLOWING SNOW...WITH TRAVEL ON EAST TO WEST ROADWAYS...ESPECIALLY
HIGHWAYS 24 AND 94 ACROSS NORTHEASTERN EL PASO COUNTY...AS WELL AS I-
25 FROM MONUMENT NORTH TO DENVER...LIKELY BEING VERY HAZARDOUS THIS
MORNING. WITH THAT SAID...HAVE KEPT CURRENT WINTER STORM WARNING IN
PLACE ACROSS NORTHERN EL PASO COUNTY FOR IMPACT OF SNOW AND BLOWING
AND NOT FOR ACTUAL SNOW ACCUMULATIONS. FURTHER SOUTH AND EAST ACROSS
THE PLAINS...COULD SEE SOME TRAVEL ISSUES IN BLOWING DUST AS
WELL...THOUGH WITH MUCH OF THE PLAINS SEEING SOME RECENT
PRECIPITATION...THINK BLOWING DUST WILL BE TOO LOCALIZED FOR ANY
HIGHLIGHTS ATTM.
A RAW AND BLUSTERY DAY EXPECTED ACROSS THE AREA WITH HIGHS ONLY IN
THE 20S AND 30S AS WINDS SLOWLY DIMINISH FROM WEST TO EAST THROUGH
THE AFTERNOON. WITH A COLD AIRMASS IN PLACE AND DECOUPLING WINDS
THROUGH THE EVENING...WILL LIKELY SEE TEMPERATURES TANK ACROSS THE
HIGHER TERRAIN AND VALLEY LOCALES OVERNIGHT...WITH LOWS IN THE
SINGLE DIGITS AND TEENS ACROSS THE EASTERN PLAINS AND MAINLY SINGLE
DIGITS ABOVE AND BELOW ZERO ACROSS THE HIGHER TERRAIN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 331 AM MST TUE DEC 23 2014
AREA WILL BE BETWEEN WEATHER SYSTEMS ON WED AS UPPER RIDGE
MIGRATES WESTWARD THROUGH THE ROCKIES. SHOULD SEE MAX TEMPS BOUNCE
BACK INTO THE 30S AND 40S MOST LOCATIONS...AND FEW SPOTS ALONG AND
JUST WEST OF I-25 MAY APPROACH 50F AS WEAK DOWNSLOPE WINDS
DEVELOP.
NEXT UPPER TROUGH IS ALREADY ONSHORE ACROSS THE PACIFIC
NORTHWEST WEDNESDAY NIGHT...WITH SYSTEM THEN DROPPING INTO THE
GREAT BASIN ON THU. SURFACE PRESSURE FALLS OVER THE EASTERN PLAINS
WED NIGHT WILL BEGIN TO INCREASE DOWNSLOPE WINDS OVER THE EASTERN
MOUNTAINS AND ADJACENT PLAINS...KEEPING LOW TEMPS RATHER MILD
ALONG AND WEST OF I-25. ON THU...UPPER TROUGH BEGINS TO MARCH
EASTWARD OUT OF THE GREAT BASIN TOWARD COLORADO...WITH MODELS
CONTINUING TO CONVERGE ON A DUE EASTWARD TRACK THROUGH THE STATE
LATE THU NIGHT INTO FRI. SNOW WILL REACH THE CONTINENTAL DIVIDE BY
MIDDAY THU...WITH A PERIOD OF HEAVY SNOW POSSIBLE LATE THU/THU
NIGHT. WILL LIKELY NEED A ROUND OF WINTER HIGHLIGHTS FOR HIGHER
DIVIDE ZONES ONCE AGAIN...THOUGH WILL LET TODAY`S HIGHLIGHTS
EXPIRE BEFORE ISSUING ANY NEW ONES. FARTHER EAST...DOWNSLOPE WINDS
WILL INCREASE OVER THE EASTERN MOUNTAINS AND ADJACENT PLAINS
THU...WITH SOME GUSTS IN THE 40-50 KNOT RANGE THU MORNING IN THE
LEE OF THE SOUTHERN SANGRES AS BAND OF STRONGER 700 MB WINDS
MOVES THROUGH. SURFACE COLD FRONT LOOKS TO HANG UP ALONG OR NORTH
OF THE PALMER DIVIDE FOR MUCH OF THE DAY THU...WHICH SHOULD KEEP
MILD AIR IN PLACE OVER MOST OF THE PLAINS...WHERE MAX TEMPS WILL
CLIMB INTO THE 50S...AIDED BY GUSTY WEST WINDS.
COLD FRONT THEN SWEEPS SOUTHWARD THROUGH THE STATE THU NIGHT AS
UPPER TROUGH CROSSES THE STATE. MOST MOUNTAIN AREAS WILL SEE AT
LEAST A QUICK BURST OF ACCUMULATING SNOW THU NIGHT...WITH SOME
LIGHT POST FRONTAL SNOW OVER THE PLAINS AS WELL. NOT EXPECTING BIG
SNOW ACCUMS OVER THE EASTERN MOUNTAINS AND PLAINS...BUT WITH LOW
LEVEL FLOW TURNING BRIEFLY UPSLOPE ALONG I-25 LATE THU
NIGHT...EASTERN MOUNTAINS/RATON MESA/PALMER DIVIDE COULD SEE AT
LEAST A FEW INCHES OF ACCUMULATION BY EARLY FRI MORNING. MAIN
PORTION OF THE UPPER TROUGH MOVES EASTWARD INTO THE PLAINS
FRI...THOUGH SOME WEAKER ENERGY DIVING INTO THE BACKSIDE OF THE
SYSTEM COMBINED WITH PERSISTENT SHALLOW UPSLOPE FLOW WILL KEEP
SOME LIGHT SNOW SHOWERS GOING OVER THE MOUNTAINS AND HIGHER
TERRAIN WEST OF I-25 THROUGH THE DAY. TEMPS FRI WILL RISE LITTLE
AS COLDER AIR POURS SOUTH ACROSS THE REGION...AND SUSPECT MOST
LOCATIONS WILL STAY AT OR BELOW FREEZING FOR MAXES.
A FEW FLURRIES MAY LINGER OVER THE MOUNTAINS EARLY SAT BEFORE
UPPER ENERGY MOVES EAST OF THE STATE...WITH GENERALLY DRY
CONDITIONS FROM SAT AFTERNOON INTO SUN...THOUGH MAX TEMPS WILL
REMAIN BELOW SEASONAL AVERAGES BOTH DAYS. WESTERN TROUGH RELOADS
EARLY NEXT WEEK AS MORE ENERGY DROPS SOUTH TOWARD THE GREAT BASIN
WHILE A RENEWED SURGE OF COLD AIR SPILLS SOUTH OVER THE PLAINS.
MAIN PORTION OF THE TROUGH COULD STAY TOO FAR WEST TO PRODUCE
HEAVY SNOW OVER THE AREA...THOUGH RATHER DEEP UPSLOPE FLOW OVER
THE EASTERN MOUNTAINS AND PLAINS MAY LEAD TO A PROLONGED LIGHT TO
MODERATE SNOW EVENT MON INTO TUE. CURRENT POPS EARLY NEXT WEEK ARE
ON THE LOW SIDE SO FAR...AND WILL LIKELY NEED TO BE INCREASED AS
EVENT COMES INTO BETTER FOCUS LATER THIS WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1055 AM MST TUE DEC 23 2014
VFR CONDITIONS EXPECTED AT THE THREE MAIN TAF SITES OF KCOS...KPUB
AND KALS FOR THE NEXT 24 HRS. GUSTY NORTH WINDS WILL BE ON THE
WANE FROM WEST TO EAST THROUGH THE AFTN. MOORE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ095>099.
HIGH WIND WARNING UNTIL 11 AM MST THIS MORNING FOR COZ085-086.
HIGH WIND WARNING UNTIL 2 PM MST THIS AFTERNOON FOR COZ089-093-
094.
WINTER STORM WARNING UNTIL 11 AM MST THIS MORNING FOR COZ084.
&&
$$
UPDATE...MOORE
SHORT TERM...MW
LONG TERM...PETERSEN
AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
935 AM MST TUE DEC 23 2014
.UPDATE...
ISSUED AT 933 AM MST TUE DEC 23 2014
QUICK UPDATE TO ADJUST CLOUD COVER AND POPS FROM THE EASTERN MTS
WESTWARD. ONGOING FORECAST GRIDS FOR THE E PLAINS LOOK GOOD AT
THIS TIME. MOORE
UPDATE ISSUED AT 713 AM MST TUE DEC 23 2014
WINDS CONTINUE TO SLOWLY INCREASE ACROSS THE EASTERN PLAINS WITH
HIGHEST RECORDED GUST IN PAST HOUR OF 46KTS AT SPD. WINDS AND
SNOWFALL LAGGING ACROSS THE PALMER DVD...THOUGH STILL SEEING SOME
ECHOES ACROSS DOUGLAS AND LINCOLN COUNTIES...WHICH COULD POSE
TRAVEL IMPACTS ACROSS PORTIONS OF NORTHEASTERN EL PASO COUNTY AND
THE PALMER DVD. WITH THAT SAID...WILL KEEP WINTER STORM WARNING
ONGOING FOR NORTHERN EL PASO COUNTY FOR NOW...DUE TO POSSIBLE
VISIBILITY REDUCTIONS AND TRAVEL IMPACTS IN LIGHT SNOW AND BLOWING
SNOW...AS ANY ADDITIONAL ACCUMULATIONS ARE EXPECTED TO LIGHT AND
SPOTTY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM MST TUE DEC 23 2014
...STRONG WINDS ACROSS EASTERN COLORADO TODAY...
NO BIG CHANGES TO CURRENT FORECAST WITH STRONG NORTHERLY WINDS
GUSTING TO BETWEEN 50 AND 60 MPH EXPECTED ACROSS MUCH OF EASTERN
COLORADO LATER THIS MORNING AND AFTERNOON...WITH A STRONG SFC-H7
GRADIENT SETTING UP ACROSS THE PLAINS AS UPPER JET CORE ACROSS
WESTERN COLORADO THIS MORNING TRANSLATES EAST THROUGH THE AFTERNOON.
AS OF 3 AM...STARTING TO SEE GUSTY NORTH TO NORTHWEST WINDS OF 20 TO
40 MPH ACROSS NORTHEASTERN COLORADO REACHING AS FAR SOUTH AS LIMON
AND BURLINGTON...WITH BEST 3HRLY SFC PRESSURE RISES OF 2-3 MBS STILL
ACROSS NORTHEASTERN COLORADO AND SOUTHWESTERN NEBRASKA. WITH THAT
SAID...SHOULD SEE STRONG NORTHERLY WINDS HITTING THE PALMER DVD
WITHIN THE NEXT HOUR OR SO...WHICH WILL CONTINUE TO STRENGTHEN AS
SFC PRESSURE GRADIENT TIGHTENS AND CONTINUES SOUTH AND EAST ACROSS
THE REST OF THE SOUTHEAST PLAINS THROUGH THE REST OF THE MORNING.
LATEST HIGHER RESOLUTION HRRR AND RAP MODELS KEEP MOST OF
PRECIPITATION OUT ACROSS THE FAR SE PLAINS AND ALONG THE SOUTHERN
COLORADO AND NEW MEXICO BORDER TODAY...WITH ONE BAND MOVING SOUTH
AND EAST OF BURLINGTON ATTM. HOWEVER...LATEST RADAR AND SATELLITE
INDICATING SOME ENHANCED ECHOES NORTHEAST OF EL PASO AND LINCOLN
COUNTIES...AND WITH THE STRONG NORTHERLY WINDS HITTING THE PALMER
DIVIDE...STILL SHOULD SEE AN ENHANCED PERIOD OF WIND DRIVEN SNOW
ACROSS NORTHERN PORTIONS OF EL PASO COUNTY THROUGH THE MORNING
DRIVE...WITH A FEW INCHES OF ADDITIONAL ACCUMULATIONS POSSIBLE.
THE MAIN ISSUE...HOWEVER...WILL BE EXPECTED POOR VISIBILITIES IN
BLOWING SNOW...WITH TRAVEL ON EAST TO WEST ROADWAYS...ESPECIALLY
HIGHWAYS 24 AND 94 ACROSS NORTHEASTERN EL PASO COUNTY...AS WELL AS I-
25 FROM MONUMENT NORTH TO DENVER...LIKELY BEING VERY HAZARDOUS THIS
MORNING. WITH THAT SAID...HAVE KEPT CURRENT WINTER STORM WARNING IN
PLACE ACROSS NORTHERN EL PASO COUNTY FOR IMPACT OF SNOW AND BLOWING
AND NOT FOR ACTUAL SNOW ACCUMULATIONS. FURTHER SOUTH AND EAST ACROSS
THE PLAINS...COULD SEE SOME TRAVEL ISSUES IN BLOWING DUST AS
WELL...THOUGH WITH MUCH OF THE PLAINS SEEING SOME RECENT
PRECIPITATION...THINK BLOWING DUST WILL BE TOO LOCALIZED FOR ANY
HIGHLIGHTS ATTM.
A RAW AND BLUSTERY DAY EXPECTED ACROSS THE AREA WITH HIGHS ONLY IN
THE 20S AND 30S AS WINDS SLOWLY DIMINISH FROM WEST TO EAST THROUGH
THE AFTERNOON. WITH A COLD AIRMASS IN PLACE AND DECOUPLING WINDS
THROUGH THE EVENING...WILL LIKELY SEE TEMPERATURES TANK ACROSS THE
HIGHER TERRAIN AND VALLEY LOCALES OVERNIGHT...WITH LOWS IN THE
SINGLE DIGITS AND TEENS ACROSS THE EASTERN PLAINS AND MAINLY SINGLE
DIGITS ABOVE AND BELOW ZERO ACROSS THE HIGHER TERRAIN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 331 AM MST TUE DEC 23 2014
AREA WILL BE BETWEEN WEATHER SYSTEMS ON WED AS UPPER RIDGE
MIGRATES WESTWARD THROUGH THE ROCKIES. SHOULD SEE MAX TEMPS BOUNCE
BACK INTO THE 30S AND 40S MOST LOCATIONS...AND FEW SPOTS ALONG AND
JUST WEST OF I-25 MAY APPROACH 50F AS WEAK DOWNSLOPE WINDS
DEVELOP.
NEXT UPPER TROUGH IS ALREADY ONSHORE ACROSS THE PACIFIC
NORTHWEST WEDNESDAY NIGHT...WITH SYSTEM THEN DROPPING INTO THE
GREAT BASIN ON THU. SURFACE PRESSURE FALLS OVER THE EASTERN PLAINS
WED NIGHT WILL BEGIN TO INCREASE DOWNSLOPE WINDS OVER THE EASTERN
MOUNTAINS AND ADJACENT PLAINS...KEEPING LOW TEMPS RATHER MILD
ALONG AND WEST OF I-25. ON THU...UPPER TROUGH BEGINS TO MARCH
EASTWARD OUT OF THE GREAT BASIN TOWARD COLORADO...WITH MODELS
CONTINUING TO CONVERGE ON A DUE EASTWARD TRACK THROUGH THE STATE
LATE THU NIGHT INTO FRI. SNOW WILL REACH THE CONTINENTAL DIVIDE BY
MIDDAY THU...WITH A PERIOD OF HEAVY SNOW POSSIBLE LATE THU/THU
NIGHT. WILL LIKELY NEED A ROUND OF WINTER HIGHLIGHTS FOR HIGHER
DIVIDE ZONES ONCE AGAIN...THOUGH WILL LET TODAY`S HIGHLIGHTS
EXPIRE BEFORE ISSUING ANY NEW ONES. FARTHER EAST...DOWNSLOPE WINDS
WILL INCREASE OVER THE EASTERN MOUNTAINS AND ADJACENT PLAINS
THU...WITH SOME GUSTS IN THE 40-50 KNOT RANGE THU MORNING IN THE
LEE OF THE SOUTHERN SANGRES AS BAND OF STRONGER 700 MB WINDS
MOVES THROUGH. SURFACE COLD FRONT LOOKS TO HANG UP ALONG OR NORTH
OF THE PALMER DIVIDE FOR MUCH OF THE DAY THU...WHICH SHOULD KEEP
MILD AIR IN PLACE OVER MOST OF THE PLAINS...WHERE MAX TEMPS WILL
CLIMB INTO THE 50S...AIDED BY GUSTY WEST WINDS.
COLD FRONT THEN SWEEPS SOUTHWARD THROUGH THE STATE THU NIGHT AS
UPPER TROUGH CROSSES THE STATE. MOST MOUNTAIN AREAS WILL SEE AT
LEAST A QUICK BURST OF ACCUMULATING SNOW THU NIGHT...WITH SOME
LIGHT POST FRONTAL SNOW OVER THE PLAINS AS WELL. NOT EXPECTING BIG
SNOW ACCUMS OVER THE EASTERN MOUNTAINS AND PLAINS...BUT WITH LOW
LEVEL FLOW TURNING BRIEFLY UPSLOPE ALONG I-25 LATE THU
NIGHT...EASTERN MOUNTAINS/RATON MESA/PALMER DIVIDE COULD SEE AT
LEAST A FEW INCHES OF ACCUMULATION BY EARLY FRI MORNING. MAIN
PORTION OF THE UPPER TROUGH MOVES EASTWARD INTO THE PLAINS
FRI...THOUGH SOME WEAKER ENERGY DIVING INTO THE BACKSIDE OF THE
SYSTEM COMBINED WITH PERSISTENT SHALLOW UPSLOPE FLOW WILL KEEP
SOME LIGHT SNOW SHOWERS GOING OVER THE MOUNTAINS AND HIGHER
TERRAIN WEST OF I-25 THROUGH THE DAY. TEMPS FRI WILL RISE LITTLE
AS COLDER AIR POURS SOUTH ACROSS THE REGION...AND SUSPECT MOST
LOCATIONS WILL STAY AT OR BELOW FREEZING FOR MAXES.
A FEW FLURRIES MAY LINGER OVER THE MOUNTAINS EARLY SAT BEFORE
UPPER ENERGY MOVES EAST OF THE STATE...WITH GENERALLY DRY
CONDITIONS FROM SAT AFTERNOON INTO SUN...THOUGH MAX TEMPS WILL
REMAIN BELOW SEASONAL AVERAGES BOTH DAYS. WESTERN TROUGH RELOADS
EARLY NEXT WEEK AS MORE ENERGY DROPS SOUTH TOWARD THE GREAT BASIN
WHILE A RENEWED SURGE OF COLD AIR SPILLS SOUTH OVER THE PLAINS.
MAIN PORTION OF THE TROUGH COULD STAY TOO FAR WEST TO PRODUCE
HEAVY SNOW OVER THE AREA...THOUGH RATHER DEEP UPSLOPE FLOW OVER
THE EASTERN MOUNTAINS AND PLAINS MAY LEAD TO A PROLONGED LIGHT TO
MODERATE SNOW EVENT MON INTO TUE. CURRENT POPS EARLY NEXT WEEK ARE
ON THE LOW SIDE SO FAR...AND WILL LIKELY NEED TO BE INCREASED AS
EVENT COMES INTO BETTER FOCUS LATER THIS WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 331 AM MST TUE DEC 23 2014
MAIN AVIATION CONCERN CONTINUES TO BE STRONG NORTHERLY WINDS
ACROSS THE EASTERN PLAINS THIS MORNING THROUGH THE EARLY
AFTERNOON...WITH GUSTS TO 50KTS POSSIBLE AT COS AND PUB. THERE IS
A LOW PROBABILITY BRIEF IFR CONDITIONS WITH SNOW AND BLOWING AT
BOTH COS AND PUB THIS MORNING...THOUGH WILL ONLY KEEP VCSH AT COS
WITH ACCUMULATING SNOW STAYING NORTH ALONG THE PALMER DVD. WINDS
DIMINISH THROUGH THE AFTERNOON WITH VFR CONDITIONS EXPECTED
THEREAFTER. VFR CONDITIONS EXPECTED AT ALS OVER THE NEXT 24 HOURS
WITH BREEZY NORTH TO NORTHWEST WINDS THROUGH THE AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ095>099.
HIGH WIND WARNING UNTIL 11 AM MST THIS MORNING FOR COZ085-086.
HIGH WIND WARNING UNTIL 2 PM MST THIS AFTERNOON FOR COZ089-093-
094.
WINTER STORM WARNING UNTIL 11 AM MST THIS MORNING FOR COZ084.
&&
$$
UPDATE...MOORE
SHORT TERM...MW
LONG TERM...PETERSEN
AVIATION...MW
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1236 PM CST TUE DEC 23 2014
.UPDATE...
1037 AM CST
CHRISTMAS EVE STORM UPDATE...
THE LATEST AVAILABLE 12Z GUIDANCE HAS HONED IN PRETTY CLOSELY ON A
LOW PRESSURE TRACK FROM FROM CENTRAL KY TO NEAR IND TO CENTRAL OR
SOUTHWEST LOWER MI ON WEDNESDAY. THIS GIVES US MORE CONFIDENCE IN
WHERE THE HEAVIEST SWATH OF PRECIPITATION WILL FALL IN THE INTENSE
DEFORMATION AXIS. THERE IS A STILL A SIGNIFICANT TIMING
DISCREPANCY BETWEEN THE NAM ON THE SLOW END OF THE GUIDANCE
ENVELOPE AND 12Z GFS ON THE FASTEST END...AS IT HAS CONSISTENTLY
SHOWN FOR SEVERAL MODEL CYCLES. SO CONFIDENCE IS LOWER ON TIMING
AND DURATION OF HEAVY PRECIP...WITH THE GFS SUGGESTING THAT THE
BULK OF THE PRECIPITATION FALLS BETWEEN 06Z AND 18Z...WHILE THE
NAM FAVORS THE HEAVIEST PRECIPITATION OVER THE CHICAGO METRO AND
POINTS EAST FROM THE LATE MORNING UNTIL THE LATE AFTERNOON.
THE BIGGEST QUESTION MARK REMAINS WITH THE VERY MARGINAL BOUNDARY
LAYER CONDITIONS FOR SNOW AT PRECIP ONSET AND THROUGH MUCH OF THE
EVENT. PRECIPITATION IS EXPECTED TO START AS RAIN THEN FLIP OVER
TO SNOW. THE THINKING IS THAT THE GFS IS NOT HANDLING THE DYNAMIC
COOLING OFFERED BY THE INTENSE UPWARD MOTION IN THE HEART OF THE
FRONTOGENETICALLY DRIVEN DEFORMATION BAND...AND THUS REMAINS TOO
WARM WITH NEAR SFC THERMAL PROFILES AND MOST OF THE PRECIP FALLS
IN THE FORM OF RAIN/MIX. THE FORECAST WILL LEAN IN FAVOR OF
DYNAMIC COOLING OFFSETTING THE INITIALLY MARGINAL
CONDITIONS...WHICH IS CAPTURED WELL BY THE 12Z NAM. HOWEVER...IT
WILL LIKELY BE A VERY LOW SNOW TO LIQUID RATIO SNOW AND THE HUGE
SNOWFALL AMOUNTS ON THE NAM COBB OUTPUT ARE VERY LIKELY OVERDONE.
WOULD LIKE TO SEE THE REST OF THE 12Z GUIDANCE BEFORE MAKING ANY
HEADLINE DECISIONS...WHICH WILL LIKELY BE MADE BY THE EARLY
AFTERNOON. OVERALL THINKING REMAINS THAT CONFIDENCE IS GROWING IN
A HIGH IMPACT SNOW EVENT ACROSS PART OF THE CWA TOMORROW...WHICH
IS BECOMING MORE LIKELY TO INCLUDE THE CHICAGO METRO. THE SPS HAS
BEEN UPDATED.
RC
&&
.SHORT TERM...
TODAY...
331 AM CST
STACKED UPPER/SURFACE LOW PRESSURE WAS OVER IOWA EARLY THIS
MORNING...WITH SURFACE OCCLUSION/WARM FRONT EXTENDING EAST AND
SOUTHEAST ACROSS NORTHERN ILLINOIS INTO WEST CENTRAL INDIANA. AREA
OF STEADIER MODERATE RAIN WAS LIFTING NORTH OF THE IL/WI BORDER...
WITH ONLY SPOTTY SHOWERS OR SOME LINGERING DRIZZLE EXPECTED THIS
MORNING WITHIN SYSTEM DRY SLOT. UPPER LOW IS PROGGED TO WEAKEN AND
SHEAR NORTHEAST ACROSS THE NORTHERN GREAT LAKES THROUGH THIS
AFTERNOON...WITH ITS SURFACE LOW ALSO MOVING NORTHEAST OF THE AREA
AND ALLOWING SOUTHERLY WINDS TO MAINTAIN RELATIVELY MILD WEATHER
ACROSS THE FORECAST AREA WITH TEMPS GENERALLY HOLDING IN THE 40S.
MAY SEE SOME BREAKS IN THE CLOUDS AS SKIES HAVE CLEARED UPSTREAM
ACROSS MISSOURI...THOUGH WILL LIKELY SEE REDEVELOPMENT OF LOWER
CLOUDS IN MOIST LOW LEVEL ENVIRONMENT AND WEAK WEAK TROUGHING
ALOFT.
RATZER
TONIGHT THROUGH WEDNESDAY NIGHT...
323 AM CST
HIGH IMPACT WINTER STORM WITH HEAVY WET SNOW POSSIBLE CHRISTMAS EVE.
GENERALLY SPEAKING...WE ARE IN A MUCH BETTER PLACE WITH RESPECT TO
MODEL AGREEMENT THIS MORNING THAN WE WERE LAST NIGHT OR EVEN 12
HOURS AGO. HOWEVER...THERE REMAIN SOME DIFFERENCES WITH RESPECT TO
THE EXACT TRACK AND SPEED/TIMING OF THE SYSTEM. OTHER FORECAST
BUGABOO IS THE MARGINAL LOW LEVEL THERMAL PROFILES DURING THE HEART
OF THE EVENT.
WHILE THERE ARE STILL DIFFERENCES...ONE THING THE COLLECTION OF
MODEL GUIDANCE HAS NOW COME AROUND TO IS THE IDEA OF AN EXPLOSIVELY
DEEPENING CYCLONE DEVELOPING TRACKING NORTH FROM THE GULF COAST
TODAY TO LOWER MICHIGAN BY CHRISTMAS EVE NIGHT. EVENING UPPER AIR
ANALYSIS DEPICTED 170KT 250MB JET SAMPLED BY 00Z RAOB AT SALT LAKE
CITY...WITH THIS JET DIVING DOWN THE BACK SIDE OF THE LONG WAVE
TROUGH AND PROGGED TO SHARPEN/AMPLIFY SOUTHERN FLANK OF THE TROUGH
OVER THE SOUTHERN PLAINS TODAY. THE UPPER JET EMERGES FROM THE BASE
OF THE TROUGH WEDNESDAY GUIDANCE DEPICTS A RAPIDLY DEEPENING CYCLONE
WITH CIRCULATION PROGGED TO CLOSE OFF ALL THE WAY UP TO 300MB.
THE RAPID DEEPENING AND QUICK MOVEMENT OF THE MID/UPPER LEVEL LOW
WILL LIKELY RESULT IN EXTREMELY IMPRESSIVE LARGE SCALE FORCING WITH
AN IMPRESSIVE TROWAL/DEFORMATION ZONE LIKELY TO DEVELOP ON THE
WESTERN FLANK OF THE CYCLONE. VERY STRONG LOW/MID LEVEL
FRONTOGENESIS WILL OCCUR WITHIN THE TROWAL AND COINCIDENT WITH THE
RAPIDLY STRENGTHENING CYCLONE WILL PROMOTE STRONG VERTICAL
CIRCULATION. GUIDANCE ALSO SUGGESTS WEAKLY STABLE TO UNSTABLE
CONDITIONS ALOFT WITHIN THIS TROWAL WITH NEGATIVE EPV AND STEEP
MID-HIGH LEVEL LAPSE RATES...WHICH GIVEN THE STRONG FRONTOGENESIS
WOULD TEND TO FAVOR A NARROWER BUT INTENSE PRECIPITATION BAND.
GFS/WRF-NAM BOTH INDICATE THE PRESENCE OF SOME WEAK UPRIGHT
INSTABILITY WHICH GIVEN THE FORCING COULD ALLOW FOR UPRIGHT
CONVECTION WITHIN THE DEFO BAND AND POSSIBLY A COUPLE LIGHTNING
STRIKES.
WHILE GUIDANCE IS IN PRETTY GOOD AGREEMENT ON THE ABOVE...THERE ARE
A COUPLE OF KEY AREAS OF LINGERING UNCERTAINTY. FIRST...MODEL
BOUNDARY LAYER THERMAL PROFILES ARE FORECAST TO BE QUITE MARGINAL
FOR SNOW AND EVEN MORE MARGINAL FOR ACCUMULATING SNOW. DESPITE THE
MARGINAL THERMAL PROFILES...AM FAIRLY CONFIDENT THAT DYNAMIC COOLING
WITHIN THE DEFO BAND WILL LIKELY EASILY COOL THE BOUNDARY LAYER
SUFFICIENTLY TO SUPPORT ACCUMULATING SNOW...PARTICULARLY WHERE THE
HEAVIEST PRECIP OCCURS. THE 02/07/13 SYSTEM IS A PRIME EXAMPLE OF A
CASE OF VERY STRONG DYNAMIC COOLING THAT WAS VERY POORLY HANDLED BY
THE MODELS AND RESULTED IN NEARLY 10 INCHES OF SNOW WHERE MODELS
GUIDANCE FORECAST SFC TEMPS IN THE MID TO UPPER 30S.
THE BIGGER UNCERTAINTY AND WHAT IS KEEPING ME FROM JUMPING OUT WITH
A WINTER STORM WATCH AT THIS TIME IS THE TRACK DIFFERENCES IN THE
MODELS. WHILE THEY ARE NOT HUGE AND NOT SURPRISING GIVEN THE RAPIDLY
DEEPENING NATURE OF THE SYSTEM...THEY ARE SUBSTANTIAL ENOUGH TO MAKE
IT TOUGH TO PINPOINT THE PORTION OF OUR CWA MOST AT RISK. GIVEN
COMBINATION OF STRONG FRONTOGENESIS...INSTABILITY...AND MARGINAL
THERMAL PROFILES IT SEEMS LIKELY THE AREAL EXTENT OF HEAVY SNOW
WOULD NOT BE LARGE WITH POTENTIALLY SHARP CUT OFF ON BOTH THE
WESTERN AND EASTERN FLANKS OF THE SNOW BAND...SIMILAR TO WHAT WAS
SEEN IN THE 12/01/2006 SYSTEM WHICH IS ONE OF THE STRONGEST ANALOGS
FOR THIS SYSTEM AND PRODUCED LOCALLY OVER A FOOT OF SNOW.
THE CURRENT SNOWFALL FORECAST MAP WAS CREATED BLENDING VARYING
MODEL TRACK SOLUTIONS TOGETHER WHICH YIELD SNOWFALL AMOUNTS THAT
WILL LIKELY BE TOO LOW WHERE THE HEAVIEST SNOW FALLS AND TOO HIGH
OUTSIDE OF THAT BAND...BUT LIKELY THE BEST COMPROMISE THAT CAN BE
DONE FROM THIS DISTANCE GIVEN WHAT LOOKS TO BE A MESOSCALE HEAVY
SNOW THAT WILL SET UP. WHERE THE HEAVY SNOW BAND SETS UP...THINK IT
IS PRETTY LIKELY THAT VSBYS OF 1/4SM OR LESS WITH HEAVY WET SNOW ARE
LIKELY WITH SNOWFALL RATES >/= 2 INCHES PER HOUR POSSIBLE. THE PEAK
INTENSITY OF THE SNOW LOOKS TO COINCIDE WITH THE DAYTIME HOURS WHEN
MANY PEOPLE WILL LIKELY BE TRAVELING...SO ASSUMING THE BAND SETS UP
AS EXPECTED...IT COULD MAKE TRAVEL EXTREMELY DIFFICULT TOMORROW
AFTERNOON. SOME MODELS ARE AS FAR WEST AS NW IL INTO RFD (PARALLEL
GFS AND WRF-NMM) RANGING TO AS FAR EAST AS NORTHWEST INDIANA (00Z
ECMWF). WOULD TEND TO FAVOR THE MORE WESTERN SOLUTIONS AS RAPIDLY
DEEPENING CYCLONES TYPICALLY TEND TO END UP FARTHER WEST THAN
PROGGED WHICH COULD FAVOR CHICAGO AREA OR POINTS JUST WEST FOR THE
HEAVY SNOW THREAT. BUT WITH A STILL RELATIVELY LARGE SPREAD IN TRACK
SOLUTIONS WOULD BE DIFFICULT TO PIN POINT A SPECIFIC AREA FOR A
WINTER STORM WATCH WHEN IN REALITY THE HEAVY (6"+) SNOW AMOUNTS
COULD BE CONFINED TO <25MI WIDE SWATH. AFTER COORDINATION
INTERNALLY...WITH NEIGHBORING WFOS...AND WPC HAVE OPTED TO JUST HIT
THE THREAT HARD IN UPDATED SPS AND HOPEFULLY MORNING MODEL RUNS WILL
NARROW DOWN THE THREAT AREA ENOUGH TO ALLOW HEADLINES TO BE ISSUED
BY MIDDAY.
IZZI
&&
.LONG TERM...
331 AM CST
THURSDAY THROUGH MONDAY...
DEEPENING LOW PRESSURE FROM CHRISTMAS EVE STORM LIFTS QUICKLY AWAY
FROM THE REGION THURSDAY MORNING...WITH BUILDING UPPER RIDGE ALOFT
BETWEEN DEPARTING LOW AND UPSTREAM TROUGH OVER THE WESTERN CONUS.
GUIDANCE IN REASONABLE AGREEMENT IN SENDING A LEAD SHORT WAVE
NORTHEAST TOWARD THE UPPER MIDWEST ON FRIDAY...WITH SURFACE LOW
PRESSURE TRACKING TO OUR NORTHWEST FROM IOWA TO THE UPPER PENINSULA
OF MICHIGAN. SOUTHERLY FLOW DEVELOPS IN ADVANCE OF THIS SYSTEM AND
ITS TRAILING COLD FRONT...WITH TEMPERATURES SURGING BACK INTO THE
40S FRIDAY. MODEL QPF IS HIGHEST FARTHER SOUTH AHEAD OF THE COLD
FRONT ACROSS THE LOWER OHIO VALLEY...THOUGH IT DOES LOOK LIKE A
POTENTIAL FOR SOME LIGHT RAIN OR RAIN/SNOW MIX TO DEVELOP ACROSS THE
AREA FRIDAY NIGHT...WITH SOME LINGERING LIGHT SNOW OR SNOW SHOWERS
LINGERING ACROSS THE SOUTHEASTERN CWA SATURDAY AS COLDER AIR SPREADS
IN ON BLUSTERY WEST-NORTHWEST WINDS.
STRONG HIGH PRESSURE THEN BUILDS SOUTHEAST ACROSS THE PLAINS AND
UPPER MIDWEST INTO SUNDAY...THOUGH ECMWF MAINTAINS A LITTLE LIGHT
PRECIPITATION ALONG THE RETREATING BAROCLINIC ZONE TO OUR SOUTHEAST
AND HAVE KEPT SOME LOW POPS FOR LIGHT SNOW SATURDAY NIGHT AND SUNDAY
FOR SOUTH AND EAST OF THE CHICAGO AREA. THE REMNANT WESTERN CONUS
UPPER TROUGH THEN MOVES EAST ACROSS THE SOUTHERN PLAINS AND LOWER
MISSISSIPPI/OHIO VALLEYS SUNDAY NIGHT. DRY NORTHERLY FLOW
AROUND THE UPPER MIDWEST HIGH...WITH GENERALLY DRY AND SEASONABLY
COLD WEATHER SUNDAY INTO MONDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* BURST OF HEAVY WET SNOW LIKELY WEDNESDAY FROM MIDDAY THROUGH THE AFTERNOON.
* A PERIOD OF VLIFR CONDITIONS POSSIBLE WEDNESDAY AFTERNOON WITH
HEAVY WET SNOW.
* EXACT LOCATION OF BAND OF HEAVIEST SNOW REMAINS UNCERTAIN. SNOW
AMOUNTS WILL DROP OFF SHARPLY TO EITHER SIDE.
ED F
//DISCUSSION...UPDATED 18Z...
COMPLICATED WEATHER SITUATION UNFOLDING FOR WEDNESDAY WITH
POTENTIAL FOR VERY LOW CIGS AND VSBYS ASSOCIATED WITH BAND OF
HEAVY WET SNOW. FIRST... SOUTHWEST WINDS WILL CONTINUE TO GUST
20-25 KT THIS AFTERNOON WITH LOW CLOUDS LURKING JUST TO THE
NORTHWEST OF ORD/MDW AS LOW PRESSURE TRACKS NE ACROSS WISCONSIN
REACHING NORTHERN LAKE MICHIGAN TONIGHT. WINDS WILL SLACKEN AS THE
LOW PULLS AWAY TONIGHT WITH CIGS LOWERING OVERNIGHT.
MEANWHILE... POWERFUL LOW PRESSURE MOVING FROM THE OHIO VALLEY TO
LOWER MICHIGAN BY LATE DAY WEDNESDAY WILL LIKELY BRING RAIN
CHANGING TO HEAVY WET SNOW QUICKLY WEDNESDAY MID-LATE MORNING WITH
THE POTENTIAL FOR SNOWFALL RATES OF 1 TO LOCALLY OVER 2 INCHES PER
HOUR WITH VERY LOW CIGS AND VSBYS POSSIBLE. WHILE MODELS TRENDING MORE
CONSISTENT ON OVERALL SCENARIO... DIFFERENCES REMAIN THAT CAN MAKE
THE DIFFERENCE IN EXACTLY WHERE THE NARROW BAND OF HEAVIEST SNOW
THAT THIS SYSTEM IS CAPABLE OF WILL SET UP. COMING FORECASTS
WILL SEEK TO FURTHER REFINE THE EXACT LOCATION OF THIS
POTENTIALLY HIGHLY IMPACTFUL EVENT.
ED F
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH ON CIG TRENDS AND WINDS THIS AFTERNOON/EVENING.
* MEDIUM TO HIGH ON POTENTIAL FOR SNOW ON WEDNESDAY...BUT LOW ON
ONSET TIMING AND TIMING OF CHANGE OVER FROM RA TO SN... AS WELL
AS HOW POOR CONDITIONS MAY DETERIORATE TO.
ED F
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...SNOW ENDING IN THE EVENING. IFR OR LOWER
IMPROVING.
THURSDAY...CHANCE OF MVFR CIGS...MAINLY EARLY.
FRIDAY...CHANCE OF MVFR CIGS. STRONG SOUTH WINDS POSSIBLE.
SATURDAY AND SUNDAY...CHANCE OF MVFR CIGS.
MONDAY...MAINLY VFR.
KJB
&&
.MARINE...
217 AM CST
AN INITIAL AREA OF LOW PRESSURE ACROSS SOUTHERN IOWA THIS
MORNING...WILL SHIFT A WARM FRONTAL BOUNDARY FROM NORTH TO SOUTH UP
THE LAKE DURING THE DAY. THEREFORE...SOME STIFF EASTERLIES WILL
SHIFT SOUTHERLY BY LATE IN THE DAY. FOLLOWING THIS...IT STILL
APPEARS LIKELY THAT A SECOND RATHER SIGNIFICANT STORM SYSTEM WILL
RAPIDLY DEVELOP NEAR THE GULF COAST AND RACE NORTHWARD...WHILE
DEEPENING CONSIDERABLE...ACROSS THE OHIO VALLEY AND OVER THE CENTRAL
GREAT LAKES REGION BY CHRISTMAS EVE. DUE TO THE STRENGTH OF THIS
LOW...IT APPEARS THAT A PERIOD OF GALE FORCE WINDS WILL BE A DECENT
POSSIBLY...ESPECIALLY OVER THE OPEN WATERS CHRISTMAS EVE.
THEREFORE...I HAVE ISSUED A GALE WATCH FOR THE OPEN WATERS OF LAKE
MICHIGAN. DUE TO THE FAST MOVEMENT OF THE STORM...WINDS LOOK TO DROP
BELOW GALE FORCE BY CHRISTMAS DAY. STRONG WINDS AND HIGH WAVES ARE
ALSO EXPECTED OVER THE NEAR SHORE WATERS. HOWEVER...I HAVE OPTED
TO LEAVE THE GALE WATCH OUT OF THE NEAR SHORE WATERS AT THIS
TIME...THOUGH SOME GALES CANT BE RULED OUT.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM WEDNESDAY TO 3 AM
THURSDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...6 PM WEDNESDAY TO 6 AM THURSDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1140 AM CST Tue Dec 23 2014
.UPDATE...
ISSUED AT 1030 AM CST TUE DEC 23 2014
Weak low pressure center at the sfc moving NE from east central IA
this morning, as a dry slot built into Central Illinois resulting
in long absent sunshine for the area. Cirrus building in from the
south will slowly cloud back over and the day should wrap up
rather cloudy again. Temperatures on track for the afternoon with
southwesterly winds. Quiet weather expected through the afternoon,
with a break between the two systems. Forecast looking good and no
updates are anticipated in the short term.
&&
.SHORT TERM...(Today)
ISSUED AT 506 AM CST TUE DEC 23 2014
Initial shortwave associated with a closed low at 500 mb early this
morning was tracking across north central Illinois. Back edge of the
rain has shifted into our east and northeast counties...soon to exit
our area for this morning. Mid level dry slot seen on satellite data
tracking east into parts of west central Illinois. Most of the short
term models shift the lower clouds to our northeast this morning
allowing some breaks to develop. HRRR and RUC soundings showing
the low level moisture slowly lifting with time this morning, but
that shouldn`t last long as mid and high level clouds start to stream
northeast into our area ahead of the second shortwave that will bring
another round of rain, then snow to our area starting tonight. Air
mass in the wake of the weak frontal passage today not very cold at
all, in fact, 925-850 mb temperature forecasts suggests highs this
afternoon will range from the upper 40s north to the middle 50s
southeast.
&&
.LONG TERM...(Tonight through Monday)
ISSUED AT 335 AM CST TUE DEC 23 2014
Will be issuing a Special Weather Statement to address the 1-3inch
snow accumulations with locally 3 to 4 inches west of I-57 to near
the IL river on Wed and Wed evening. 00Z models have trended
further west (especially NAM model) up Indiana Wed with
deformation/trowal setting up over central and northeast IL on Wed.
Rain spread back northward across se IL this evening and over rest
of central IL overnight with chance of light snow late tonight
west of the IL river. But appears warm enough for most areas
tonight to just get rain. Lows tonight in mid 30s from I-55 nw to
upper 30s to around 40F in eastern/southeast IL.
Surface low pressure to deepen and lift nne from the nw Gulf of
Mexico across central Indiana Wed and into eastern lower MI by Wed
evening. Strong upper level low to pivot across IL Wed afternoon
and expect rain to change to wet snow from west to east during the
day Wed. Snow to diminish from west to east during Wed night. Best
snow accumulations to occur over western IL Wed morning with 1
inch or less while snow accumulations 1-3 inches from IL river
east toward I-57 Wed afternoon/evening with locally 3-4 inches
near I-55 and into ne IL. Morning highs Wed in mid to upper 30s
central IL and lower 40s eastern/se IL and then slipping into low
to mid 30s by end of day Wed as strong west/nw winds kick in
during day Wed into Wed night with gusts 25 to 35 mph.
Christmas day still looks dry with return of some sunshine
especially sw counties as strong low pressure exits into Quebec
and 1025 mb surface high pressure sets up over southeast states.
A southerly flow sets up by Thu afternoon with highs in the upper
30s to lower 40s so any snow that fall Wed/Wed evening will likely
melt on Thu afternoon.
Another area of low pressure ejects ne from CO into WI by Fri
evening and swings a cold front se across central IL Fri night and
near southeast IL Sat. Milder highs in mid to upper 40s on Friday
with IL getting in warm sector. Then precipitation chances
increasing during Friday night into Sat especially over southeast
IL. Southeast IL looks warm enough for mainly rain (turning to mix
during day on Sat) with mix of light rain/snow central IL but
little accumulations. Highs Sat range from lower 30s nw of IL
river to lower 40s along the Wabash River.
ECMWF model is further north with southern low pressure system and
qpf into southeast IL Sat night through Sunday eve and drawing in
colder air and cold enough for light snow. Have chance of light
snow southeast IL Sat night and Sunday with slight chances over
central IL. Seasonably cold highs in the low to mid 30s on Sunday.
Quieter weather returns early next work week with seasonable temps
for late Dec.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1136 AM CST TUE DEC 23 2014
Not much in the way of changes in the shorter term TAF this
morning. Cirrus closing in the gap in the dry slot this morning
and mid level clouds anticipated by later this afternoon. Winds
becoming light and variable in the evening as MVFR clouds begin to
build back into the region from the SE as the next low pressure
system slides north into the area. Same low pressure system will
bring increasing chances for rain, eventually changing over to
snow mid morning. Timing is still low confidence, but needed to
start the trend. Should be all snow by noon in both SPI and PIA
and close to all snow in other terminals as well.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...Smith
LONG TERM...07
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1037 AM CST TUE DEC 23 2014
.UPDATE...
1037 AM CST
CHRISTMAS EVE STORM UPDATE...
THE LATEST AVAILABLE 12Z GUIDANCE HAS HONED IN PRETTY CLOSELY ON A
LOW PRESSURE TRACK FROM FROM CENTRAL KY TO NEAR IND TO CENTRAL OR
SOUTHWEST LOWER MI ON WEDNESDAY. THIS GIVES US MORE CONFIDENCE IN
WHERE THE HEAVIEST SWATH OF PRECIPITATION WILL FALL IN THE INTENSE
DEFORMATION AXIS. THERE IS A STILL A SIGNIFICANT TIMING
DISCREPANCY BETWEEN THE NAM ON THE SLOW END OF THE GUIDANCE
ENVELOPE AND 12Z GFS ON THE FASTEST END...AS IT HAS CONSISTENTLY
SHOWN FOR SEVERAL MODEL CYCLES. SO CONFIDENCE IS LOWER ON TIMING
AND DURATION OF HEAVY PRECIP...WITH THE GFS SUGGESTING THAT THE
BULK OF THE PRECIPITATION FALLS BETWEEN 06Z AND 18Z...WHILE THE
NAM FAVORS THE HEAVIEST PRECIPITATION OVER THE CHICAGO METRO AND
POINTS EAST FROM THE LATE MORNING UNTIL THE LATE AFTERNOON.
THE BIGGEST QUESTION MARK REMAINS WITH THE VERY MARGINAL BOUNDARY
LAYER CONDITIONS FOR SNOW AT PRECIP ONSET AND THROUGH MUCH OF THE
EVENT. PRECIPITATION IS EXPECTED TO START AS RAIN THEN FLIP OVER
TO SNOW. THE THINKING IS THAT THE GFS IS NOT HANDLING THE DYNAMIC
COOLING OFFERED BY THE INTENSE UPWARD MOTION IN THE HEART OF THE
FRONTOGENETICALLY DRIVEN DEFORMATION BAND...AND THUS REMAINS TOO
WARM WITH NEAR SFC THERMAL PROFILES AND MOST OF THE PRECIP FALLS
IN THE FORM OF RAIN/MIX. THE FORECAST WILL LEAN IN FAVOR OF
DYNAMIC COOLING OFFSETTING THE INITIALLY MARGINAL
CONDITIONS...WHICH IS CAPTURED WELL BY THE 12Z NAM. HOWEVER...IT
WILL LIKELY BE A VERY LOW SNOW TO LIQUID RATIO SNOW AND THE HUGE
SNOWFALL AMOUNTS ON THE NAM COBB OUTPUT ARE VERY LIKELY OVERDONE.
WOULD LIKE TO SEE THE REST OF THE 12Z GUIDANCE BEFORE MAKING ANY
HEADLINE DECISIONS...WHICH WILL LIKELY BE MADE BY THE EARLY
AFTERNOON. OVERALL THINKING REMAINS THAT CONFIDENCE IS GROWING IN
A HIGH IMPACT SNOW EVENT ACROSS PART OF THE CWA TOMORROW...WHICH
IS BECOMING MORE LIKELY TO INCLUDE THE CHICAGO METRO. THE SPS HAS
BEEN UPDATED.
RC
&&
.SHORT TERM...
TODAY...
331 AM CST
STACKED UPPER/SURFACE LOW PRESSURE WAS OVER IOWA EARLY THIS
MORNING...WITH SURFACE OCCLUSION/WARM FRONT EXTENDING EAST AND
SOUTHEAST ACROSS NORTHERN ILLINOIS INTO WEST CENTRAL INDIANA. AREA
OF STEADIER MODERATE RAIN WAS LIFTING NORTH OF THE IL/WI BORDER...
WITH ONLY SPOTTY SHOWERS OR SOME LINGERING DRIZZLE EXPECTED THIS
MORNING WITHIN SYSTEM DRY SLOT. UPPER LOW IS PROGGED TO WEAKEN AND
SHEAR NORTHEAST ACROSS THE NORTHERN GREAT LAKES THROUGH THIS
AFTERNOON...WITH ITS SURFACE LOW ALSO MOVING NORTHEAST OF THE AREA
AND ALLOWING SOUTHERLY WINDS TO MAINTAIN RELATIVELY MILD WEATHER
ACROSS THE FORECAST AREA WITH TEMPS GENERALLY HOLDING IN THE 40S.
MAY SEE SOME BREAKS IN THE CLOUDS AS SKIES HAVE CLEARED UPSTREAM
ACROSS MISSOURI...THOUGH WILL LIKELY SEE REDEVELOPMENT OF LOWER
CLOUDS IN MOIST LOW LEVEL ENVIRONMENT AND WEAK WEAK TROUGHING
ALOFT.
RATZER
TONIGHT THROUGH WEDNESDAY NIGHT...
323 AM CST
HIGH IMPACT WINTER STORM WITH HEAVY WET SNOW POSSIBLE CHRISTMAS EVE.
GENERALLY SPEAKING...WE ARE IN A MUCH BETTER PLACE WITH RESPECT TO
MODEL AGREEMENT THIS MORNING THAN WE WERE LAST NIGHT OR EVEN 12
HOURS AGO. HOWEVER...THERE REMAIN SOME DIFFERENCES WITH RESPECT TO
THE EXACT TRACK AND SPEED/TIMING OF THE SYSTEM. OTHER FORECAST
BUGABOO IS THE MARGINAL LOW LEVEL THERMAL PROFILES DURING THE HEART
OF THE EVENT.
WHILE THERE ARE STILL DIFFERENCES...ONE THING THE COLLECTION OF
MODEL GUIDANCE HAS NOW COME AROUND TO IS THE IDEA OF AN EXPLOSIVELY
DEEPENING CYCLONE DEVELOPING TRACKING NORTH FROM THE GULF COAST
TODAY TO LOWER MICHIGAN BY CHRISTMAS EVE NIGHT. EVENING UPPER AIR
ANALYSIS DEPICTED 170KT 250MB JET SAMPLED BY 00Z RAOB AT SALT LAKE
CITY...WITH THIS JET DIVING DOWN THE BACK SIDE OF THE LONG WAVE
TROUGH AND PROGGED TO SHARPEN/AMPLIFY SOUTHERN FLANK OF THE TROUGH
OVER THE SOUTHERN PLAINS TODAY. THE UPPER JET EMERGES FROM THE BASE
OF THE TROUGH WEDNESDAY GUIDANCE DEPICTS A RAPIDLY DEEPENING CYCLONE
WITH CIRCULATION PROGGED TO CLOSE OFF ALL THE WAY UP TO 300MB.
THE RAPID DEEPENING AND QUICK MOVEMENT OF THE MID/UPPER LEVEL LOW
WILL LIKELY RESULT IN EXTREMELY IMPRESSIVE LARGE SCALE FORCING WITH
AN IMPRESSIVE TROWAL/DEFORMATION ZONE LIKELY TO DEVELOP ON THE
WESTERN FLANK OF THE CYCLONE. VERY STRONG LOW/MID LEVEL
FRONTOGENESIS WILL OCCUR WITHIN THE TROWAL AND COINCIDENT WITH THE
RAPIDLY STRENGTHENING CYCLONE WILL PROMOTE STRONG VERTICAL
CIRCULATION. GUIDANCE ALSO SUGGESTS WEAKLY STABLE TO UNSTABLE
CONDITIONS ALOFT WITHIN THIS TROWAL WITH NEGATIVE EPV AND STEEP
MID-HIGH LEVEL LAPSE RATES...WHICH GIVEN THE STRONG FRONTOGENESIS
WOULD TEND TO FAVOR A NARROWER BUT INTENSE PRECIPITATION BAND.
GFS/WRF-NAM BOTH INDICATE THE PRESENCE OF SOME WEAK UPRIGHT
INSTABILITY WHICH GIVEN THE FORCING COULD ALLOW FOR UPRIGHT
CONVECTION WITHIN THE DEFO BAND AND POSSIBLY A COUPLE LIGHTNING
STRIKES.
WHILE GUIDANCE IS IN PRETTY GOOD AGREEMENT ON THE ABOVE...THERE ARE
A COUPLE OF KEY AREAS OF LINGERING UNCERTAINTY. FIRST...MODEL
BOUNDARY LAYER THERMAL PROFILES ARE FORECAST TO BE QUITE MARGINAL
FOR SNOW AND EVEN MORE MARGINAL FOR ACCUMULATING SNOW. DESPITE THE
MARGINAL THERMAL PROFILES...AM FAIRLY CONFIDENT THAT DYNAMIC COOLING
WITHIN THE DEFO BAND WILL LIKELY EASILY COOL THE BOUNDARY LAYER
SUFFICIENTLY TO SUPPORT ACCUMULATING SNOW...PARTICULARLY WHERE THE
HEAVIEST PRECIP OCCURS. THE 02/07/13 SYSTEM IS A PRIME EXAMPLE OF A
CASE OF VERY STRONG DYNAMIC COOLING THAT WAS VERY POORLY HANDLED BY
THE MODELS AND RESULTED IN NEARLY 10 INCHES OF SNOW WHERE MODELS
GUIDANCE FORECAST SFC TEMPS IN THE MID TO UPPER 30S.
THE BIGGER UNCERTAINTY AND WHAT IS KEEPING ME FROM JUMPING OUT WITH
A WINTER STORM WATCH AT THIS TIME IS THE TRACK DIFFERENCES IN THE
MODELS. WHILE THEY ARE NOT HUGE AND NOT SURPRISING GIVEN THE RAPIDLY
DEEPENING NATURE OF THE SYSTEM...THEY ARE SUBSTANTIAL ENOUGH TO MAKE
IT TOUGH TO PINPOINT THE PORTION OF OUR CWA MOST AT RISK. GIVEN
COMBINATION OF STRONG FRONTOGENESIS...INSTABILITY...AND MARGINAL
THERMAL PROFILES IT SEEMS LIKELY THE AREAL EXTENT OF HEAVY SNOW
WOULD NOT BE LARGE WITH POTENTIALLY SHARP CUT OFF ON BOTH THE
WESTERN AND EASTERN FLANKS OF THE SNOW BAND...SIMILAR TO WHAT WAS
SEEN IN THE 12/01/2006 SYSTEM WHICH IS ONE OF THE STRONGEST ANALOGS
FOR THIS SYSTEM AND PRODUCED LOCALLY OVER A FOOT OF SNOW.
THE CURRENT SNOWFALL FORECAST MAP WAS CREATED BLENDING VARYING
MODEL TRACK SOLUTIONS TOGETHER WHICH YIELD SNOWFALL AMOUNTS THAT
WILL LIKELY BE TOO LOW WHERE THE HEAVIEST SNOW FALLS AND TOO HIGH
OUTSIDE OF THAT BAND...BUT LIKELY THE BEST COMPROMISE THAT CAN BE
DONE FROM THIS DISTANCE GIVEN WHAT LOOKS TO BE A MESOSCALE HEAVY
SNOW THAT WILL SET UP. WHERE THE HEAVY SNOW BAND SETS UP...THINK IT
IS PRETTY LIKELY THAT VSBYS OF 1/4SM OR LESS WITH HEAVY WET SNOW ARE
LIKELY WITH SNOWFALL RATES >/= 2 INCHES PER HOUR POSSIBLE. THE PEAK
INTENSITY OF THE SNOW LOOKS TO COINCIDE WITH THE DAYTIME HOURS WHEN
MANY PEOPLE WILL LIKELY BE TRAVELING...SO ASSUMING THE BAND SETS UP
AS EXPECTED...IT COULD MAKE TRAVEL EXTREMELY DIFFICULT TOMORROW
AFTERNOON. SOME MODELS ARE AS FAR WEST AS NW IL INTO RFD (PARALLEL
GFS AND WRF-NMM) RANGING TO AS FAR EAST AS NORTHWEST INDIANA (00Z
ECMWF). WOULD TEND TO FAVOR THE MORE WESTERN SOLUTIONS AS RAPIDLY
DEEPENING CYCLONES TYPICALLY TEND TO END UP FARTHER WEST THAN
PROGGED WHICH COULD FAVOR CHICAGO AREA OR POINTS JUST WEST FOR THE
HEAVY SNOW THREAT. BUT WITH A STILL RELATIVELY LARGE SPREAD IN TRACK
SOLUTIONS WOULD BE DIFFICULT TO PIN POINT A SPECIFIC AREA FOR A
WINTER STORM WATCH WHEN IN REALITY THE HEAVY (6"+) SNOW AMOUNTS
COULD BE CONFINED TO <25MI WIDE SWATH. AFTER COORDINATION
INTERNALLY...WITH NEIGHBORING WFOS...AND WPC HAVE OPTED TO JUST HIT
THE THREAT HARD IN UPDATED SPS AND HOPEFULLY MORNING MODEL RUNS WILL
NARROW DOWN THE THREAT AREA ENOUGH TO ALLOW HEADLINES TO BE ISSUED
BY MIDDAY.
IZZI
&&
.LONG TERM...
331 AM CST
THURSDAY THROUGH MONDAY...
DEEPENING LOW PRESSURE FROM CHRISTMAS EVE STORM LIFTS QUICKLY AWAY
FROM THE REGION THURSDAY MORNING...WITH BUILDING UPPER RIDGE ALOFT
BETWEEN DEPARTING LOW AND UPSTREAM TROUGH OVER THE WESTERN CONUS.
GUIDANCE IN REASONABLE AGREEMENT IN SENDING A LEAD SHORT WAVE
NORTHEAST TOWARD THE UPPER MIDWEST ON FRIDAY...WITH SURFACE LOW
PRESSURE TRACKING TO OUR NORTHWEST FROM IOWA TO THE UPPER PENINSULA
OF MICHIGAN. SOUTHERLY FLOW DEVELOPS IN ADVANCE OF THIS SYSTEM AND
ITS TRAILING COLD FRONT...WITH TEMPERATURES SURGING BACK INTO THE
40S FRIDAY. MODEL QPF IS HIGHEST FARTHER SOUTH AHEAD OF THE COLD
FRONT ACROSS THE LOWER OHIO VALLEY...THOUGH IT DOES LOOK LIKE A
POTENTIAL FOR SOME LIGHT RAIN OR RAIN/SNOW MIX TO DEVELOP ACROSS THE
AREA FRIDAY NIGHT...WITH SOME LINGERING LIGHT SNOW OR SNOW SHOWERS
LINGERING ACROSS THE SOUTHEASTERN CWA SATURDAY AS COLDER AIR SPREADS
IN ON BLUSTERY WEST-NORTHWEST WINDS.
STRONG HIGH PRESSURE THEN BUILDS SOUTHEAST ACROSS THE PLAINS AND
UPPER MIDWEST INTO SUNDAY...THOUGH ECMWF MAINTAINS A LITTLE LIGHT
PRECIPITATION ALONG THE RETREATING BAROCLINIC ZONE TO OUR SOUTHEAST
AND HAVE KEPT SOME LOW POPS FOR LIGHT SNOW SATURDAY NIGHT AND SUNDAY
FOR SOUTH AND EAST OF THE CHICAGO AREA. THE REMNANT WESTERN CONUS
UPPER TROUGH THEN MOVES EAST ACROSS THE SOUTHERN PLAINS AND LOWER
MISSISSIPPI/OHIO VALLEYS SUNDAY NIGHT. DRY NORTHERLY FLOW
AROUND THE UPPER MIDWEST HIGH...WITH GENERALLY DRY AND SEASONABLY
COLD WEATHER SUNDAY INTO MONDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* CIGS VARIABLE THROUGH 18Z WITH MVFR CIGS IN AND OUT
* VFR CONDITIONS PREVAILING BY 18Z... MAY SEE BRIEF MVFR CONTINUING
* VLIFR CONDITIONS POSSIBLE WEDNESDAY WITH STRONG STORM SYSTEM AND
POTENTIAL FOR HEAVY WET SNOW... FROM AROUND MIDDAY THROUGH THE
AFTERNOON.
ED F
//DISCUSSION...UPDATED 12Z...
WINDS WILL PICK UP A BIT OUT OF THE SOUTH-SOUTHWEST BY MID MORNING
AS A FRONTAL BOUNDARY LIFTS NORTHWARD ACROSS THE AREA. IT ALSO
APPEARS THAT CIGS WILL BE ON AN IMPROVING TREND TODAY...WITH VFR
CONDITIONS LOOKING TO BE A GOOD POSSIBLY BY LATE MORNING. THE NEXT
MAIN WEATHER CONCERN WILL BE ON WEDNESDAY AS A STRENGTHENING STORM
SYSTEM LIFTS UP THE OHIO VALLEY AND INTO LOWER MICHIGAN. THIS
STORM SYSTEM LOOKS TO RESULT IN ANOTHER PERIOD OF PRECIPITATION
ACROSS THE AREA...AND A DECENT POTENTIAL FOR THIS TO CHANGE OVER
TO SOME HEAVY WET SNOW. ALTHOUGH CONFIDENCE IS INCREASING THAT
THIS PRECIPITATION WILL CHANGE OVER TO SNOW...UNCERTAINTY REMAINS
RATHER HIGH AS TO THE EXACT TIMING THIS MAY OCCUR ON WED. IF THE
HEAVY SNOW DOES MATERIALIZE...PERIODS OF IFR TO VLIFR VIS AND
CIGS WOULD BE LIKELY AT TIMES DURING THE DAY.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM ON CIG TRENDS... HIGH ON WINDS.
* MEDIUM TO HIGH ON POTENTIAL FOR SNOW ON WEDNESDAY...BUT LOW ON
ONSET TIMING AND TIMING OF CHANGE OVER FROM RA TO SN... AS WELL
AS HOW POOR CONDITIONS MAY DETERIORATE TO.
ED F
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...SNOW ENDING IN THE EVENING. IFR OR LOWER
IMPROVING.
THURSDAY...CHANCE OF MVFR CIGS...MAINLY EARLY.
FRIDAY...CHANCE OF MVFR CIGS. STRONG SOUTH WINDS POSSIBLE.
SATURDAY AND SUNDAY...CHANCE OF MVFR CIGS.
MONDAY...MAINLY VFR.
KJB
&&
.MARINE...
217 AM CST
AN INITIAL AREA OF LOW PRESSURE ACROSS SOUTHERN IOWA THIS
MORNING...WILL SHIFT A WARM FRONTAL BOUNDARY FROM NORTH TO SOUTH UP
THE LAKE DURING THE DAY. THEREFORE...SOME STIFF EASTERLIES WILL
SHIFT SOUTHERLY BY LATE IN THE DAY. FOLLOWING THIS...IT STILL
APPEARS LIKELY THAT A SECOND RATHER SIGNIFICANT STORM SYSTEM WILL
RAPIDLY DEVELOP NEAR THE GULF COAST AND RACE NORTHWARD...WHILE
DEEPENING CONSIDERABLE...ACROSS THE OHIO VALLEY AND OVER THE CENTRAL
GREAT LAKES REGION BY CHRISTMAS EVE. DUE TO THE STRENGTH OF THIS
LOW...IT APPEARS THAT A PERIOD OF GALE FORCE WINDS WILL BE A DECENT
POSSIBLY...ESPECIALLY OVER THE OPEN WATERS CHRISTMAS EVE.
THEREFORE...I HAVE ISSUED A GALE WATCH FOR THE OPEN WATERS OF LAKE
MICHIGAN. DUE TO THE FAST MOVEMENT OF THE STORM...WINDS LOOK TO DROP
BELOW GALE FORCE BY CHRISTMAS DAY. STRONG WINDS AND HIGH WAVES ARE
ALSO EXPECTED OVER THE NEAR SHORE WATERS. HOWEVER...I HAVE OPTED
TO LEAVE THE GALE WATCH OUT OF THE NEAR SHORE WATERS AT THIS
TIME...THOUGH SOME GALES CANT BE RULED OUT.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM WEDNESDAY TO 3 AM
THURSDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...6 PM WEDNESDAY TO 6 AM THURSDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1035 AM CST Tue Dec 23 2014
.UPDATE...
ISSUED AT 1030 AM CST TUE DEC 23 2014
Weak low pressure center at the sfc moving NE from east central IA
this morning, as a dry slot built into Central Illinois resulting
in long absent sunshine for the area. Cirrus building in from the
south will slowly cloud back over and the day should wrap up
rather cloudy again. Temperatures on track for the afternoon with
southwesterly winds. Quiet weather expected through the afternoon,
with a break between the two systems. Forecast looking good and no
updates are anticipated in the short term.
&&
.SHORT TERM...(Today)
ISSUED AT 506 AM CST TUE DEC 23 2014
Initial shortwave associated with a closed low at 500 mb early this
morning was tracking across north central Illinois. Backedge of the
rain has shifted into our east and northeast counties...soon to exit
our area for this morning. Mid level dry slot seen on satellite data
tracking east into parts of west central Illinois. Most of the short
term models shift the lower clouds to our northeast this morning
allowing some breaks to develop. HRRR and RUC soundings showing
the low level moisture slowly lifting with time this morning, but
that shouldn`t last long as mid and high level clouds start to stream
northeast into our area ahead of the second shortwave that will bring
another round of rain, then snow to our area starting tonight. Air
mass in the wake of the weak frontal passage today not very cold at
all, in fact, 925-850 mb temperature forecasts suggests highs this
afternoon will range from the upper 40s north to the middle 50s
southeast.
&&
.LONG TERM...(Tonight through Monday)
ISSUED AT 335 AM CST TUE DEC 23 2014
Will be issuing a Special Weather Statement to address the 1-3inch
snow accumulations with locally 3 to 4 inches west of I-57 to near
the IL river on Wed and Wed evening. 00Z models have trended
further west (especially NAM model) up Indiana Wed with
deformation/trowal setting up over central and northeast IL on Wed.
Rain spread back northward across se IL this evening and over rest
of central IL overnight with chance of light snow late tonight
west of the IL river. But appears warm enough for most areas
tonight to just get rain. Lows tonight in mid 30s from I-55 nw to
upper 30s to around 40F in eastern/southeast IL.
Surface low pressure to deepen and lift nne from the nw Gulf of
Mexico across central Indiana Wed and into eastern lower MI by Wed
evening. Strong upper level low to pivot across IL Wed afternoon
and expect rain to change to wet snow from west to east during the
day Wed. Snow to diminish from west to east during Wed night. Best
snow accumulations to occur over western IL Wed morning with 1
inch or less while snow accumulations 1-3 inches from IL river
east toward I-57 Wed afternoon/evening with locally 3-4 inches
near I-55 and into ne IL. Morning highs Wed in mid to upper 30s
central IL and lower 40s eastern/se IL and then slipping into low
to mid 30s by end of day Wed as strong west/nw winds kick in
during day Wed into Wed night with gusts 25 to 35 mph.
Christmas day still looks dry with return of some sunshine
especially sw counties as strong low pressure exits into Quebec
and 1025 mb surface high pressure sets up over southeast states.
A southerly flow sets up by Thu afternoon with highs in the upper
30s to lower 40s so any snow that fall Wed/Wed evening will likely
melt on Thu afternoon.
Another area of low pressure ejects ne from CO into WI by Fri
evening and swings a cold front se across central IL Fri night and
near southeast IL Sat. Milder highs in mid to upper 40s on Friday
with IL getting in warm sector. Then precipitation chances
increasing during Friday night into Sat especially over southeast
IL. Southeast IL looks warm enough for mainly rain (turning to mix
during day on Sat) with mix of light rain/snow central IL but
little accumulations. Highs Sat range from lower 30s nw of IL
river to lower 40s along the Wabash River.
ECMWF model is further north with southern low pressure system and
qpf into southeast IL Sat night through Sunday eve and drawing in
colder air and cold enough for light snow. Have chance of light
snow southeast IL Sat night and Sunday with slight chances over
central IL. Seasonably cold highs in the low to mid 30s on Sunday.
Quieter weather returns early next work week with seasonable temps
for late Dec.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 530 AM CST TUE DEC 23 2014
MVFR and local IFR cigs will become VFR this morning with PIA on
the edge of some wrap around moisture from the departing storm
system. Forecast soundings showing despite the loss of the low
level moisture, quite a bit of mid and high level cloud cover
will affect the TAF sites this morning into the afternoon hours
before more MVFR cigs approach the area for late this evening and
into the overnight hours ahead of the next storm system. As the
next storm system approaches from the south tonight, rain will
overspread the area from south to north after 04z with CMI and
DEC the first to see the rain followed by SPI and BMI aftr 06z
and then PIA during the early morning hours. Once the rain begins
it appears the cigs will quickly drop to MVFR and then eventually
IFR once again, but at this time will hold off bringing cigs and
or vsbys down too much in this forecast period as it appears the
IFR and LIFR cigs will be during the day Wed. Surface winds will
be out of the southwest today at 10 to 15 kts, and the gradually
turn into a light northwest to north direction tonight at 4 to
9 kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...Smith
LONG TERM...07
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS DES MOINES IA
325 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...23/18Z
ISSUED AT 1150 AM CST TUE DEC 23 2014
WIDESPREAD STRATUS AND VSBY RESTRICTIONS CONTINUE TO BLANKET TAF
SITES RANGING FROM MVFR SE TO IFR NW. PERSISTENT LIGHT SNOW IS
ALSO CONTRIBUTING TO VSBY REDUCTIONS SW-NE THROUGH KFOD/KMCW. CIG
SITUATION WILL CHANGE LITTLE THROUGH THE PERIOD WITH JUST SLIGHT
IMPROVEMENT TO MORE PREVALENT LOW END MVFR WED MORNING. AREA OF
LIGHT SNOW WILL GRADUALLY SHIFT SOUTH AND EAST AS WI SFC LOW FADES
AND IS REPLACED BY OH VALLEY LOW. ONLY -DZ IS ANTICIPATED AT KOTM
HOWEVER.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...ZOGG
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS JACKSON KY
429 PM EST TUE DEC 23 2014
.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.
&&
$$
SHORT TERM...DJ
LONG TERM...GEOGERIAN
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
355 PM EST TUE DEC 23 2014
.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...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 425 AM EST TUE DEC 23 2014
THE PERIOD WILL BEGIN WITH A DEEP CLOSED LOW AND ASSOCIATED SFC
SYSTEM CENTERED OVER THE GREAT LAKES REGION WITH A TROUGH EXTENDING
SOUTH INTO THE MS VALLEY. RIDGING IS EXPECTED TO BE OFF THE SOUTHEAST
US COAST WITH RIDGING ALSO OVER NORTHERN MEXICO AND INTO THE SOUTHERN
AND CENTRAL ROCKIES. A TROUGH IS EXPECTED TO BE WORKING ACROSS THE
NORTHWESTERN CONUS AT THAT POINT AS WELL. FROM THU INTO THE START OF
THE WEEKEND...THE DEEP LOW INITIALLY OVER THE GREAT LAKES WILL TRACK
NORTH ACROSS ONTARIO AND QUEBEC AND INTO THE MARITIMES WITH THE
TRAILING TROUGH AXIS MOVING ACROSS THE AREA EARLY IN THE PERIOD ON
WED NIGHT INTO EARLY ON THU. RIDGING SHOULD THEN WORK ACROSS THE
EASTERN CONUS FROM LATER ON CHRISTMAS DAY INTO FRIDAY. MEANWHILE THE
COLD FRONT TRAILING FROM THE SYSTEM MOVING THROUGH THE GREAT LAKES
INITIALLY SHOULD HAVE EXITED INTO WV OR SHOULD EXIT INTO WV VERY
EARLY IN THE PERIOD. A DRY SLOT SHOULD WORK ACROSS THE AREA EARLY IN
THE PERIOD PER RECENT MODEL CONSENSUS FOLLOWED BY SOMEWHAT DEEPER
WRAPAROUND MOISTURE LATER ON WED NIGHT. SFC HIGH PRESSURE WILL BUILD
IN BEHIND THE DEPARTING LOW PRESSURE SYSTEM FOR THU NIGHT INTO FRI
NIGHT.
FROM WED INTO FRIDAY...A TROUGH WILL HAVE DEVELOPED AND WORKED ACROSS
THE WESTERN CONUS AND SHOULD BE MOVING INTO THE PLAINS BY THE START
OF THE WEEKEND. AT THAT POINT...THE MOST RECENT GFS AND ECMWF RUNS
BEGIN TO DIFFER IN TIMING OF INDIVIDUAL WAVES BUT THERE IS A GENERAL
THEME OF LOWERING HEIGHTS ACROSS THE EASTERN SEABOARD AND SOUTHEAST
FROM THE WEEKEND INTO EARLY NEXT WEEK WITH A TROUGH OVER THE WESTERN
INTO THE CENTRAL CONUS BECOMING INCREASINGLY BROAD WITH TIME. THE
GENERAL CONSENSUS IS FOR A COLD FRONT TO ENTER THE LOWER OH AND
APPALACHIAN REGION FROM FRI NIGHT INTO SATURDAY AND THEN SHIFT SOUTH
OF THE REGION AS EARLY AS SAT AFTERNOON OR EVENING PER THE GFS AND
AS LATE SAT NIGHT INTO SUN PER THE ECMWF.
THE UPPER LEVEL TROUGH AND WRAPAROUND MOISTURE SHOULD LEAD TO SHOWER
AND DRIZZLE CHANCES FROM WED NIGHT INTO MIDDAY ON THURSDAY. SOME SNOW
COULD MIX IN AS WELL. LOCATIONS BELOW 2000 OR 2500 FEET ELEVATION
SHOULD REMAIN ABOVE FREEZING ON WED NIGHT. BEHIND THE DEPARTING
SYSTEM AND IN ADVANCE OF A SFC HIGH...THE LOW LEVEL FLOW WILL BECOME
TOO SOUTHWEST FOR IDEAL UPSLOPE FLOW BUT LOW LEVEL LAPSE RATES WILL
SUPPORT THE CHANCES FOR SHOWERS AND OR DRIZZLE. IN ADDITION...MODEL
FORECAST SOUNDINGS INDICATE THAT ICE CRYSTALS COULD BE LOST AT TIMES
LEADING TO LIGHT PRECIP POSSIBLY FALLING FROM CLOUDS WHERE ICE IS NOT
PRESENT...LEADING TO JUST RAIN OR DRIZZLE AT TIMES. THERE MAY BE
TIMES WHERE ICE IS PRESENT SO SOME FLURRIES OR LIGHT SNOW WOULD ALSO
BE POSSIBLE...BUT CHANCES FOR THIS ARE BEST ON THE RIDGES. A BIT OF
FREEZING DRIZZLE ALSO CANNOT BE RULED OUT LATE WED NIGHT INTO EARLY
ON THURSDAY FOR ELEVATIONS ABOVE 2000 OR 2500 FEET ELEVATION. THE
PRESSURE GRADIENT WILL REMAIN RATHER STEEP WELL INTO WED NIGHT...SO
WIND GUSTS AS HIGH AS 35 TO 40 MPH WILL BE POSSIBLE. A SLIGHTLY
STRONGER GUST CANNOT BE RULED OUT ABOVE 2500 FEET. AS THE MOISTURE
BECOMES INCREASINGLY SHALLOW AS CHRISTMAS DAY PROGRESSES ANY LINGERING
DRIZZLE SHOULD DISSIPATE WITH SOME PARTIAL CLEARING...ESPECIALLY IN
WESTERN SECTIONS. HIGH PRESSURE SHOULD LEAD TO DRY WEATHER FOR THU
EVENING INTO MOST OF FRIDAY NIGHT.
BOTH OF SCENARIOS FROM THE 0Z GFS AND 0Z ECMWF RUNS POINT TOWARD
MAINLY RAIN...POSSIBLY MIXING WITH OR CHANGING TO SNOW ON SAT INTO
SAT NIGHT. CURRENT MODEL RUNS HAVE A WAVE DEVELOPING ON SAT INTO SAT
NIGHT ALONG THE BOUNDARY THAT WILL HAVE PASSED TO OUR SOUTH WITH AN
INVERTED TROUGH EXTENDING TO ITS NORTH IN RESPONSE TO A SHORTWAVE
WORKING FROM HE SOUTHERN ROCKIES ACROSS THE SOUTHERN PLAINS AND INTO
THE SOUTHEASTERN CONUS FROM SAT NIGHT INTO SUN NIGHT. THE MODELS
TRACK THE SFC WAVE ACROSS THE SOUTHEASTERN STATES DURING THAT TIME. IF
DEEP ENOUGH MOISTURE LINGERS AS THIS SYSTEM DEPARTS ON SUN NIGHT INTO
EARLY ON MONDAY...SOME SNOW MIGHT MIX IN.
OVERALL..TEMPERATURES THROUGH THE PERIOD WILL REMAIN NEAR NORMAL TO
ABOVE NORMAL AS THE CORE OF THE COLDER AIRMASSES REMAINS MAINLY
BOTTLED UP OVER CANADA AND NEARER TO THE US/CANADIAN BORDER. THE
BIGGEST DEPARTURES SHOULD OCCUR FROM FRI INTO SATURDAY. SOME MODEL
GUIDANCE SUGGESTS THAT AT LEAST A GLANCING BLOW OF COLDER AIR MAY
AFFECT THE AREA AROUND THE MIDDLE OF NEXT WEEK...BUT THERE HAS BEEN
PLENTY OF MODEL DIFFERENCES FROM RUN TO RUN AND MODEL TO MODEL DURING
THAT TIME PERIOD.
&&
.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.
&&
$$
SHORT TERM...DJ
LONG TERM...JP
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
103 PM EST TUE DEC 23 2014
.UPDATE...
ISSUED AT 1020 AM EST TUE DEC 23 2014
SATELLITE THIS MORNING SHOWING A FEW BREAKS IN THE CLOUDS
PARTICULARLY ACROSS SE PORTIONS OF THE CWA. ALSO SEEING A FEW SHOWERS
MOVING ALONG THE WESTERN CWA BORDER. CLOUDS AND SHOWERS EXPECTED TO
INCREASE THROUGH THE DAY TODAY. EVEN SLIGHT CHANCE OF A THUNDERSTORM
ONCE WE MOVE INTO THE AFTERNOON HOURS FROM SW TO NE. NO MAJOR CHANGES
MADE THIS UPDATE. DID FRESHEN UP THE GRID WITH LATEST OBS AND TRENDS.
UPDATE ISSUED AT 638 AM EST TUE DEC 23 2014
NO UPDATE PLANNED THIS MORNING. SCATTERED SHOWERS CONTINUE TO SLIDE
NORTH ACROSS THE WESTERN HALF OF THE AREA. LATEST HRRR IS FLUCTUATING
A BIT NOW ON THE EXPECTED ARRIVAL OF MORE WIDESPREAD RAIN LATER THIS
AFTERNOON...BUT STILL BRINGS MOST OF IT INTO THE AREA BY EARLY
EVENING. WON`T MAKE ANY CHANGES AT THIS TIME AND SEE IF THE NEXT FEW
RUNS LOCK ONTO BETTER TIMING.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 315 AM EST TUE DEC 23 2014
A CUT OFF LOW CONTINUES TO SPIN ACROSS THE CENTRAL PLAINS THIS
MORNING WITH BROAD SOUTHWEST FLOW ACROSS THE OHIO RIVER VALLEY. LOW
LEVEL FLOW REMAINS SOUTHEAST ACROSS EASTERN KENTUCKY. A LULL IN
PRECIPITATION IS OCCURRING PRESENTLY ACROSS THE AREA AS THE LATEST
WAVE RESPONSIBLE FOR SOME RAIN EARLIER TONIGHT HAS EXITED TO THE
NORTH. HOWEVER...MORE SHOWERS ARE SPREADING NORTH OUT OF CENTRAL
TENNESSEE AND WILL PROVIDE SOME RAIN INTO SOUTHERN KENTUCKY OVER THE
NEXT FEW HOURS. THE BEST CHANCES FOR RAIN THROUGH MIDDAY WILL REMAIN
ACROSS THE WESTERN HALF OF THE AREA.
ANOTHER WILL EMERGE FROM THE UPPER LEVEL TROUGH AND PUSH NORTH ACROSS
THE TENNESSEE VALLEY THIS AFTERNOON AND EVENING...BRINGING WIDESPREAD
SHOWERS BACK TO THE AREA. THE SHOWALTER INDEX REMAINS NEGATIVE
THROUGH THE NEXT 24 TO 36 HOURS ACROSS MOST OF THE AREA. THUS...ANY
ENHANCED AREAS OF LIFT WILL PROVIDE THE POSSIBILITY OF SOME THUNDER.
THE THUNDER THREAT SHOULD REMAIN ALL ELEVATED LATER TODAY AND
TONIGHT. GIVEN THE TREMENDOUS LIFT ARRIVING LATE IN THE DAY AND THE
WIDESPREAD COVERAGE DEPICTED IN THE HRRR...HAVE OPTED FOR
CATEGORICAL POPS LATE IN THE DAY INTO TONIGHT. AS THIS INITIAL WAVE
EXITS TO THE NORTH...WE MAY SEE ANOTHER LULL THROUGH A PORTION OF
TONIGHT. HOWEVER...ANOTHER STRONG WAVE WILL PUSH NORTH LATE TONIGHT
WITH AN AREA OF LOW PRESSURE TRACKING NORTHWARD ACROSS CENTRAL
KENTUCKY. THIS WILL BRING ANOTHER ROUND OF WIDESPREAD SHOWERS AND
EMBEDDED THUNDERSTORMS TO THE AREA.
AS THE LOW PRESSURE SYSTEM STRENGTHENS AND HEADS INTO MICHIGAN ON
WEDNESDAY...IT WILL SEND A STRONG COLD FRONT TO THE EAST ACROSS
KENTUCKY. AGAIN...GOOD CONVERGENCE AND LIFT ALONG THE FRONT SHOULD
PROVIDE ANOTHER PERIOD OF WIDESPREAD SHOWERS. THIS FRONT WILL ALSO
PRODUCE THE BEST CHANCE OF THUNDER THROUGH THE FORECAST PERIOD AS IT
CROSSES THE AREA IN THE AFTERNOON AND EVENING HOURS. THIS TIME
AROUND...WE MAY BE ABLE TO GENERATE ENOUGH SURFACE BASED INSTABILITY
TO POSSIBLY MIX DOWN SOME OF THE STRONGER WINDS AS THE SHOWERS ALONG
THE FRONT PUSH EAST. THIS COULD YIELD WINDS 45+ KNOTS. EVEN WITHOUT
THE INSTABILITY...SYNOPTIC WINDS WILL TURN QUITE GUSTY JUST BEHIND
THE FRONT WITH WIND GUSTS REACHING AS HIGH AS 40 MPH AT TIMES. AS THE
FRONT PUSHES EAST...WE SHOULD FINALLY SEE PRECIPITATION COME TO AN
END FROM WEST TO EAST THROUGH THE EVENING HOURS WEDNESDAY AS A DRY
SLOT OVERSPREADS THE AREA.
TEMPERATURES WILL REMAIN ON THE MILD SIDE THROUGH WEDNESDAY WITH
HIGHS WELL INTO THE 60S BOTH DAYS AND LOWS TONIGHT ONLY IN THE 50S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 425 AM EST TUE DEC 23 2014
THE PERIOD WILL BEGIN WITH A DEEP CLOSED LOW AND ASSOCIATED SFC
SYSTEM CENTERED OVER THE GREAT LAKES REGION WITH A TROUGH EXTENDING
SOUTH INTO THE MS VALLEY. RIDGING IS EXPECTED TO BE OFF THE SOUTHEAST
US COAST WITH RIDGING ALSO OVER NORTHERN MEXICO AND INTO THE SOUTHERN
AND CENTRAL ROCKIES. A TROUGH IS EXPECTED TO BE WORKING ACROSS THE
NORTHWESTERN CONUS AT THAT POINT AS WELL. FROM THU INTO THE START OF
THE WEEKEND...THE DEEP LOW INITIALLY OVER THE GREAT LAKES WILL TRACK
NORTH ACROSS ONTARIO AND QUEBEC AND INTO THE MARITIMES WITH THE
TRAILING TROUGH AXIS MOVING ACROSS THE AREA EARLY IN THE PERIOD ON
WED NIGHT INTO EARLY ON THU. RIDGING SHOULD THEN WORK ACROSS THE
EASTERN CONUS FROM LATER ON CHRISTMAS DAY INTO FRIDAY. MEANWHILE THE
COLD FRONT TRAILING FROM THE SYSTEM MOVING THROUGH THE GREAT LAKES
INITIALLY SHOULD HAVE EXITED INTO WV OR SHOULD EXIT INTO WV VERY
EARLY IN THE PERIOD. A DRY SLOT SHOULD WORK ACROSS THE AREA EARLY IN
THE PERIOD PER RECENT MODEL CONSENSUS FOLLOWED BY SOMEWHAT DEEPER
WRAPAROUND MOISTURE LATER ON WED NIGHT. SFC HIGH PRESSURE WILL BUILD
IN BEHIND THE DEPARTING LOW PRESSURE SYSTEM FOR THU NIGHT INTO FRI
NIGHT.
FROM WED INTO FRIDAY...A TROUGH WILL HAVE DEVELOPED AND WORKED ACROSS
THE WESTERN CONUS AND SHOULD BE MOVING INTO THE PLAINS BY THE START
OF THE WEEKEND. AT THAT POINT...THE MOST RECENT GFS AND ECMWF RUNS
BEGIN TO DIFFER IN TIMING OF INDIVIDUAL WAVES BUT THERE IS A GENERAL
THEME OF LOWERING HEIGHTS ACROSS THE EASTERN SEABOARD AND SOUTHEAST
FROM THE WEEKEND INTO EARLY NEXT WEEK WITH A TROUGH OVER THE WESTERN
INTO THE CENTRAL CONUS BECOMING INCREASINGLY BROAD WITH TIME. THE
GENERAL CONSENSUS IS FOR A COLD FRONT TO ENTER THE LOWER OH AND
APPALACHIAN REGION FROM FRI NIGHT INTO SATURDAY AND THEN SHIFT SOUTH
OF THE REGION AS EARLY AS SAT AFTERNOON OR EVENING PER THE GFS AND
AS LATE SAT NIGHT INTO SUN PER THE ECMWF.
THE UPPER LEVEL TROUGH AND WRAPAROUND MOISTURE SHOULD LEAD TO SHOWER
AND DRIZZLE CHANCES FROM WED NIGHT INTO MIDDAY ON THURSDAY. SOME SNOW
COULD MIX IN AS WELL. LOCATIONS BELOW 2000 OR 2500 FEET ELEVATION
SHOULD REMAIN ABOVE FREEZING ON WED NIGHT. BEHIND THE DEPARTING
SYSTEM AND IN ADVANCE OF A SFC HIGH...THE LOW LEVEL FLOW WILL BECOME
TOO SOUTHWEST FOR IDEAL UPSLOPE FLOW BUT LOW LEVEL LAPSE RATES WILL
SUPPORT THE CHANCES FOR SHOWERS AND OR DRIZZLE. IN ADDITION...MODEL
FORECAST SOUNDINGS INDICATE THAT ICE CRYSTALS COULD BE LOST AT TIMES
LEADING TO LIGHT PRECIP POSSIBLY FALLING FROM CLOUDS WHERE ICE IS NOT
PRESENT...LEADING TO JUST RAIN OR DRIZZLE AT TIMES. THERE MAY BE
TIMES WHERE ICE IS PRESENT SO SOME FLURRIES OR LIGHT SNOW WOULD ALSO
BE POSSIBLE...BUT CHANCES FOR THIS ARE BEST ON THE RIDGES. A BIT OF
FREEZING DRIZZLE ALSO CANNOT BE RULED OUT LATE WED NIGHT INTO EARLY
ON THURSDAY FOR ELEVATIONS ABOVE 2000 OR 2500 FEET ELEVATION. THE
PRESSURE GRADIENT WILL REMAIN RATHER STEEP WELL INTO WED NIGHT...SO
WIND GUSTS AS HIGH AS 35 TO 40 MPH WILL BE POSSIBLE. A SLIGHTLY
STRONGER GUST CANNOT BE RULED OUT ABOVE 2500 FEET. AS THE MOISTURE
BECOMES INCREASINGLY SHALLOW AS CHRISTMAS DAY PROGRESSES ANY LINGERING
DRIZZLE SHOULD DISSIPATE WITH SOME PARTIAL CLEARING...ESPECIALLY IN
WESTERN SECTIONS. HIGH PRESSURE SHOULD LEAD TO DRY WEATHER FOR THU
EVENING INTO MOST OF FRIDAY NIGHT.
BOTH OF SCENARIOS FROM THE 0Z GFS AND 0Z ECMWF RUNS POINT TOWARD
MAINLY RAIN...POSSIBLY MIXING WITH OR CHANGING TO SNOW ON SAT INTO
SAT NIGHT. CURRENT MODEL RUNS HAVE A WAVE DEVELOPING ON SAT INTO SAT
NIGHT ALONG THE BOUNDARY THAT WILL HAVE PASSED TO OUR SOUTH WITH AN
INVERTED TROUGH EXTENDING TO ITS NORTH IN RESPONSE TO A SHORTWAVE
WORKING FROM HE SOUTHERN ROCKIES ACROSS THE SOUTHERN PLAINS AND INTO
THE SOUTHEASTERN CONUS FROM SAT NIGHT INTO SUN NIGHT. THE MODELS
TRACK THE SFC WAVE ACROSS THE SOUTHEASTERN STATES DURING THAT TIME. IF
DEEP ENOUGH MOISTURE LINGERS AS THIS SYSTEM DEPARTS ON SUN NIGHT INTO
EARLY ON MONDAY...SOME SNOW MIGHT MIX IN.
OVERALL..TEMPERATURES THROUGH THE PERIOD WILL REMAIN NEAR NORMAL TO
ABOVE NORMAL AS THE CORE OF THE COLDER AIRMASSES REMAINS MAINLY
BOTTLED UP OVER CANADA AND NEARER TO THE US/CANADIAN BORDER. THE
BIGGEST DEPARTURES SHOULD OCCUR FROM FRI INTO SATURDAY. SOME MODEL
GUIDANCE SUGGESTS THAT AT LEAST A GLANCING BLOW OF COLDER AIR MAY
AFFECT THE AREA AROUND THE MIDDLE OF NEXT WEEK...BUT THERE HAS BEEN
PLENTY OF MODEL DIFFERENCES FROM RUN TO RUN AND MODEL TO MODEL DURING
THAT TIME PERIOD.
&&
.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...DJ
SHORT TERM...KAS
LONG TERM...JP
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1222 PM EST TUE DEC 23 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EST TUE DEC 23 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO
CENTERED NEAR OMAHA BTWN BIG UPR RDG ALONG THE W COAST AND ANOTHER
OFF THE E COAST. THE WRN GREAT LKS ARE UNDER THE SW FLOW ALOFT E OF
THIS FEATURE. WV IMAGERY SHOWS A RATHER IMPRESSIVE SHRTWV LIFTING TO
THE NE THRU IL E OF THE CLOSED LO WITH AREA OF COOLING CLD TOP TEMPS
CORRESPONDING TO WHETHER THE MODELS ARE SHOWING SOME IMPRESSIVE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV. EVEN THOUGH THE
SHARPER DYNAMIC FORCING IS STILL WELL S OF UPR MI EARLY THIS MRNG...
SOME LIGHT SN INVADED THE AREA LAST EVNG UNDER SOME DEEP ISENTROPIC
ASCENT/DEEP SATURATION SHOWN ON THE 00Z GRB RAOB /00Z PWAT WAS 0.57
INCH OR 225 PCT OF NORMAL AT GRB/WELL TO THE NE OF THE CLOSED LO.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS MAINLY ON POPS/QPF/PTYPE
ASSOCIATED WITH THE STRONG SHRTWV OVER IL THAT WL LIFTING QUICKLY
NNEWD TODAY AND GOING HEADLINES.
TODAY...IL SHRTWV IS FCST TO LIFT NEWD TO NEAR MENOMINEE/ESCANABA BY
18Z AND THEN TO FAR ERN LAKE SUP BY 00Z TUE. SHARP DPVA/DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE IS FCST TO IMPACT THE CWA
THRU THE DAY BEFORE BEGINNING TO SUBSIDE LATE. THE SHARPER FORCING
IS FCST TO GLANCE THE WRN ZNS. MODELS HAVE SHOWN GOOD CONTINUITY IN
FCSTG AN AXIS OF HIER H7 SPECIFIC HUMIDITY ARND 3 G/KG AND AN AXIS
OF SHARPER H85-7 FGEN THAT IS FCST TO ROTATE NWWD AND BE ORIENTED IN
A LINE OVER THE CENTRAL CWA BY 18Z ON THE CYC SIDE OF THE SHRTWV
TRACK. THIS DEFORMATION BAND SHOULD SERVE AS THE FOCUS FOR THE
HEAVIEST PCPN. H7 SPECIFIC HUMIDITY AT 3 G/KG SUPPORTS ABOUT 6
INCHES OF SN IN THE 12HR PERIOD OF EXPECTED FORCING...IN GOOD
AGREEMENT WITH HPC FCST STRIPE OF 4 TO 6 INCHES OF SN OVER THE
CENTRAL CWA. RATHER HI AND THIN DGZ BTWN 10-13K FT WL LIMIT SN/WATER
RATIOS...SO THE SN WL BE WET AND HEAVY. EVENTUAL DRY SLOTTING TO THE
E OF THIS DEFORMATION ZN BY 18Z OVER THE SE AND EXPANDING NEWD THRU
THE AFTN WL LIMIT SN TOTALS IN THAT AREA AS THE PCPN. THERE ARE ALSO
PTYPE CONCERNS...ESPECIALLY OVER THE E HALF. THE 00Z NAM FCST SDNGS
SHOW A BIT OF AN ELEVATED WARM LYR WITH WARM NOSE/H9 TEMP ABOVE 0C
CENTERED ARND H9 MOVING AS FAR W AS IRON MOUNTAIN AND THEN
ENVELOPING MUCH OF THE NCNTRL COUNTIES. GIVEN THE SW-NE FCST TRACK
OF THE SHRTWV WL FOLLOW THE SOMEWHAT COLDER 00Z CNDN MODEL FCST
TEMPS...WHICH IS SUPPORTED BY THE 00Z GFS AND LATEST RAPID REFRESH
MODELS. THESE MODELS HINT THE PCPN WL MIX WITH OR CHANGE TO RA E OF
LINE FM MARQUETTE TO IRON MOUTNAIN...CONSISTENT WITH THE AXIS OF THE
DEFORMATION ZN AND SHARPER UVV ON ITS CYC SIDE THAT WL TEND TO
OFFSET THE WAA. THE ONLY EXCEPTION WL BE NEAR LK SUP FM THE KEWEENAW
TO MARQUETTE...WHERE HIER SFC TEMPS NEAR THE WARMING INFLUENCE OF LK
SUP WL SUPPORT AT LEAST A MIX WITH SOME RA. FOR LOCATIONS AWAY FM
FAR SRN MENOMINEE COUNTY AND THE IMMEDIATE LK MI/BAY OF GREEN BAY
SHORES...THE MIX WITH OR CHANGE TO RA/DZ WL NOT OCCUR UNTIL AFTER
THE HEAVIER DEFORMATION ZN SN BAND HAS LIFTED TO THE NW. ADDED A
MENTION OF SOME FOG LATER TODAY OVER THE E WITH HI LLVL RH/MELTING
SN WITH MAX TEMPS NEAR 35 UNDER SOME MID LVL DRYING. OVERALL... THE
INHERITED HEADLINES WITH ADVYS FOR THE ENTIRE CWA STILL LOOK OKAY.
ALTHOUGH THE SHARPER FORCING WL MISS THE FAR WRN CWA...STILL LOOKING
FOR 2 TO 4 INCHES OF WET SNOW IN THAT AREA...ENUF TO JUSTIFY THE
ADVY.
TNGT...IN THE WAKE OF DEPARTING SHRTWV...DEEP LYR QVECTOR DVGC IS
FCST TO DOMINATE THE CWA...WITH EXPANDING MID LVL DRYING. EXPECT THE
HIER POPS IN THE EVNG OVER THE W UNDER LINGERING DEEPER MSTR. WITH
THE SHALLOW MOIST LYR BLO THE DGZ...NOT OUT OF THE QUESTION THERE
COULD BE SOME FREEZING DZ...ESPECIALLY OVER THE HIER TERRAIN OF THE
NCENTRAL AND W WHERE NNE FLOW WL UPSLOPE AND TEMPS WL BE AOB 32. BUT
RELATIVELY UNSTABLE NATURE OF THE LLVL LAPSE RATES WL LIMIT THIS
POTENTIAL. MIN TEMPS WL BE WELL ABOVE NORMAL FOR THE SEASON...NO
LOWER THAN THE UPR 20S OVER THE INTERIOR W. MAINTAINED MENTION OF
FOG THRU THE NGT OVER THE E HALF WHERE TEMPS ARE LIKELY TO REMAIN
ABOVE 32 WITH MOIST AIR OVER MELTING SN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 503 AM EST TUE DEC 23 2014
FOLLOWED THE ECMWF/GEM FOR THE TRACK OF THE LOW PRESSURE SYSTEM
LIFTING JUST EAST OF LOWER MICHIGAN WEDNESDAY AFTN INTO CHIRSTMAS
EVE. GIVEN THE STRENGTH OF THE JET STREAK UP TO 180 KTS OVER THE
INTERMOUNTAIN WEST AND COULPLE OF STRONGER SHORTWAVES DIGGING INTO
THE BASE OF CNTRL PLAINS TROUGH...THINK GFS AND PARALLEL GFS MODELS
ARE TOO QUICK TO BRING THE SHORTWAVE NORTH TO MICHIGAN ON WEDNESDAY
WHICH ALSO PUSHES THE LOW FARTHER TO THE WEST COMPARED TO OTHER
MODELS. 00Z NAM WAS ON THE SLOWER SIDE BUT WOULD TEND TO BUY THAT
IDEA GIVEN HOW FAR SOUTH THIS WAVE WILL INITIALLY DIG INTO TX BEFORE
LIFTING BACK TO THE NORTH. ESSENTIALLY ECMWF/GEM AND NAM IDEAS KEEP
BULK OF DEFORMATION PRECIP JUST NORTHWEST OF SFC-H85 LOWS...MAINLY
IN THE FORM OF SNOW...JUST EAST OF THE CWA. FOR THE POPS/QPF/SNOW
FOLLOWED CLOSELY TO THE WPC GUIDANCE WHICH RESULTED IN CATEGORICAL
POPS FOR LUCE COUNTY LATE WEDNESDAY AFTN INTO CHRISTMAS EVE. HIGH
POPS TAPER QUICKLY TO THE WEST MORE INTO THE CENTRAL CWA.
FOR MOST OF THE CWA ON WEDNESDAY...MAIN CONCERN WILL BE LINGERING
LGT SNOW IN WAKE OF THE SYSTEM MOVING THROUGH TODAY. SOUNDINGS STILL
SHOWING DZ/FZDZ SIGNAL AS WELL WITH MOISTURE UP TO AROUND -7C AND
DRYING ABOVE. HIT THE SNOW AND DRIZZLE CHANCES HARDEST WHERE
NORTHERLY WINDS PROVIDE ADDITIONAL UPSLOPE LIFTING...SO MAINLY OVER
PORTIONS OF WEST AND NCNTRL UPR MICHIGAN. PASSAGE OF WEAK NORTHERN
STREAM WAVE WITH DEEPER MOISTURE LIKELY ENDS THE FZDZ/DZ REGIME BY
CHRISTMAS EVE EVENING. AS LONG AS LOW PRESSURE SYSTEM OVER CNTRL
GREAT LAKES DOES NOT COME ANY FARTHER WEST...WILL SEE ANY LGT SNOW
TAPERING OFF BY MIDNIGHT FOR FAR EAST. TOTAL SNOW ACCUMS AS IT
STANDS NOW COULD BE A FEW INCHES TOWARD KERY. THIS IDEA MATCHES WPC
SNOW FORECASTS FAIRLY WELL. TEMPS THROUGOUT THE WED-WED NIGHT TIME
FRAME REMAIN MILD WITH LOW TO MID 30S ON WED AND UPR 20S TO LOW 30S
WED NIGHT.
ON CHRISTMAS DAY...A COOLISH AIRMASS ALOFT /H85 TEMPS -10C/ IN WAKE
OF THE NORTHERN STREAM TROUGH MAY RESULT IN WEAK LAKE ENHANCED SNOW
FOR WNW FLOW AREAS...BUT OTHERWISE APPEARS TO BE A QUIET DAY WITH
CONTINUED ABOVE NORMAL TEMPS IN THE LOW-MID 30S. TIGHTER PRESSURE
GRADIENT ON WEST EDGE OF DEEPENING LOW LIFTING TOWARD JAMES BAY MAY
LEAD TO SOME GUSTY WINDS AND BLSN OVER FAR EAST CWA TO START THE
DAY...BUT THIS SHOULD EASE QUICKLY.
ON TO THE NEXT SYSTEM THAT COULD IMPACT THE UPPER GREAT LAKES. TREND
OF DEEPER/SLOWER SHORTWAVE TROUGH OVER CNTRL CONUS BY FRIDAY IS
EMERGING. RESULT IS MORE DEVELOPED SFC LOW PRESSURE SYSTEM AND AREA
OF LGT TO MODERATE SNOW ORIENTED SW-NE ON NORTHWEST SIDE OF H85 LOW.
MIXING RATIOS INTO THE SYSTEM A SHADE OVER 2 G/KG AND SLR/S WILL BE
HIGHER AS COLDER AIR WILL HAVE WORKED FM THE NORTHERN PLAINS TO THE
UPPER GREAT LAKES. OVERALL A SWATH OF MODERATE SNOW MAY OCCUR...
PEGGED TO MAINLY IMPACT WESTERN SECTIONS OF UPR MICHIGAN FRIDAY
AFTN/FRIDAY NIGHT. ONSHORE FLOW AND TEMPS COLD ENOUGH COULD LEAD TO
LAKE ENHANCEMENT OVER WESTERN TIER OF UPR MICHIGAN FOR AREAS FAVORED
BY NW WINDS. WILL CONTINUE TO MENTION IN THE HWO.
LAKE EFFECT LIKELY IN THE WAKE OF THIS SYSTEM AS TEMPS CONTINUE TO
COOL WITH READINGS BLO -15C BY LATE IN THE WEEKEND. BLYR DRYING OUT
AND INCREASING SFC RIDGING WILL LIKELY PUT CRIMP INTO THE LES. KEPT
POPS SIMILAR TO PREVIOUS FORECAST FOR THE WEEKEND...WITH LIKELY POPS
IN THE NW FLOW AREAS NEAR LK SUPERIOR. AFTER THE MILD DAYTIME TEMPS
THIS WEEK...THE COOLING TEMPS WILL BE NOTICABLE WITH READINGS ONLY
IN THE TEENS TO LOWER 20S BY SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1220 PM EST TUE DEC 23 2014
EXPECT LIFR/VLIFR CONDITIONS TO PREDOMINATE THIS FCST PERIOD AT ALL
3 TAF SITES. GUSTY ENE WINDS MAY CAUSE ENUF BLSN AT THE EXPOSED CMX
LOCATION TO CAUSE VSBYS THERE TO FALL TOWARD VLIFR AS
WELL...ESPECIALLY IN THE EARLY AFTN WHEN STRONGER DYNAMIC FORCING WL
IMPACT THAT LOCATION. THE DISTURBANCE/DEEP MSTR WL EXIT LATE TODAY/
TNGT...SO THE SN WL DIMINISH. BUT LINGERING ALBEIT WEAKENING CYC NNE
FLOW OFF LK SUP WL MAINTAIN OVC LO CLDS/LIFR CIGS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EST TUE DEC 23 2014
LOW PRESSURE SLOWLY LIFTING OVER THE WESTERN GREAT LAKES TODAY WILL
RESULT IN EAST WINDS ON LK SUPERIOR...PERHAPS GUSTING TO GALE FORCE
OVER WESTERN LK SUPERIOR. WINDS WILL DIMINISH TONIGHT INTO WEDNESDAY
AS THE LOW SLIDES DIRECTLY OVER LAKE SUPERIOR. AS THE LOW WEAKENS...
ANOTHER MUCH STRONGER DEEPENING LOW WILL LIFT NORTHWARD OVER THE
CENTRAL GREAT LAKES BY WEDNESDAY NIGHT. EXPECT NORTHERLY WINDS TO
INCREASE TO 30 KTS OVER EASTERN LK SUPERIOR CLOSER TO THE STRONG LOW
PRESSURE SYSTEM. THE PRESSURE GRADIENT WILL BE TIGHEST ON THE WEST
FLANK OF THIS LOW LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING.
GALE GUSTS COULD OCCUR OVER EASTERN LK SUPERIOR AT THAT TIME. WINDS
BACK NW ON THURSDAY AND DIMINISH TO LESS THAN 20 KTS BY AFTN AS THE
LOW PRESSURE SYSTEM MOVES FARTHER AWAY FM THE AREA. ANOTHER LOW
PRESSURE SYSTEM WILL SLIDE OUT OF THE PLAINS OVER THE UPPER GREAT
LAKES FRIDAY INTO SATURDAY. NORTHERLY WINDS WILL BACK NORTHWEST AND
MAY REACH 30 KTS ON SATURDAY...MAINLY OVER EAST HALF OF LK SUPERIOR.
WINDS DIMINISH AGAIN BY SUNDAY AS HIGH PRESSURE BEGINS TO BUILD
TOWARD THE REGION FM THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>007-009>011-084-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ012>014.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...07
MARINE...JLA
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
300 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...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1120 AM CST TUE DEC 23 2014
IFR CEILINGS WILL LIKELY PREVAIL THROUGH MOST OF THE PERIOD. BAND
OF PCPN...MIXED RAIN AND SNOW...WILL CONTINUE TO DROP SOUTHEAST
ACROSS KLNK AND KOMA. THIS WILL LIKELY TURN TO MAINLY SNOW LATER
THIS AFTN AND CONTINUE INTO EARLY EVENING BEFORE ENDING. VSBYS MAY
DROP TO AROUND 1 MILE IN THE PREVAILING SNOW. FOR KOFK...LOOK FOR
SCT AREAS OF LIGHT SNOW OR SNOW SHOWERS THE REST OF THE DAY.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...FOBERT
LONG TERM...FOBERT
AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
242 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 /20Z TUESDAY THROUGH SUNDAY/...
THE ONLY CONFIDENCE IN THE AVIATION FORECAST TODAY IS IN THE BROAD
GENERALITIES OF THE WEATHER PATTERN AS THE DETAILS AT EACH
AIRPORT IS SUJECT TO THE SUBTLTIES OF LOCAL TERRAIN. THE FORECAST
AREA IS WITHIN A VEERING SOUTHEAST TO SOUTHWEST FLOW FROM THE SFC-
10KFT WHICH WILL CONTINUE TO SUPPORT A STRONG TEMPERATURE
INVERSION THAT SHOULD LOCKS IN RESTRICTIVE FLIGHT CATEGORIES FOR
THE FORSEEABLE FUTURE.
THAT SAID...THE SOUTHEASTERLY FLOW IN THE LOW LEVELS WILL IMPINGE
UPON THE TERRAIN CAUSING SOME FLUCTUATION IN THE GENERAL IDEA OF
THE FORECAST. KSYR WILL BENEFIT FROM DOWNSLOPE FLOW WITH MOST OF THE REST
OF TODAY FLUCTUATING BETWEEN VFR AND MVFR. A SIMILAR STORY EXISTS
AT KAVP WHERE THE RIDGE LINE TO THE SOUTHEAST OF AIRPORT ALLOWS
VLIFR TO STICK IN THE MOUNTAINS AND MVFR TO PREVAIL RIGHT OVER THE
TERMINAL. MVFR WILL ALSO DOMINATE AT KRME...ALTHOUGH POOR CONDITIONS CAN
SNEAK...UNNANOUNCED UP THE MOHAWK VALLEY. EVERYWHERE ELSE...IFR
IS EXPECTED AT KELM/KBGM AND CAN BE IN AND OUT AT KITH AS TERRAIN
FLOW CHANGES.
HIGH-REZ MODELS ALL SUGGEST THAT AS WARM ADVECTION STRENGTHENS
THIS EVENING...THE CHANCE FOR DRIZZLE WILL INCREASE AND CIGS/VSBYS
WILL LOWER A CATEGORY OR TWO AT ALL STATIONS TONIGHT WITH THE
DOMINANT FLIGHT CATEGORY BEING IFR WITH FUEL ALTERNATES NECESSARY
AT SOME SITES. DON/T THINK WE WILL BE SHUTTING DOWN TO AIRPORT
MINS ANYWHERE...BUT MAY COME CLOSE AT TIMES. THE MAIN BULK OF RAIN
ALONG WITH THE WORST CONDITIONS IS EXPECTED TO ARRIVE FROM SW-NE
WELL AFTER MIDNIGHT WITH WIDESPREAD IFR/VLIFR/FUEL ALTS EXPECTED
INTO WEDNESDAY.
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
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
213 PM EST TUE DEC 23 2014
.SYNOPSIS...
LIGHT RAIN AND PATCHY DRIZZLE WILL CONTINUE THIS AFTERNOON AND
EVENING AS A WEAK SURFACE LOW MOVES UP THE EAST COAST. A STRONGER
STORM SYSTEM MOVING UP FROM THE GULF OF MEXICO WILL BRING A MORE
WIDESPREAD RAIN TO CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA
LATE TONIGHT THROUGH EARLY CHRISTMAS MORNING. A STRONG FRONT WILL
MOVE THROUGH CHRISTMAS MORNING BRINGING STRONG GUSTY WINDS TO THE
AREA, WITH LINGERING RAIN SHOWERS MIXING WITH SNOW SHOWERS.
&&
.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/...
335 AM UPDATE...
CWA WL BE IN A LULL THE FIRST PART OF TONIGHT AS SFC LOW ALONG THE
ERN SEABOARD FILLS AND SYSTEM OVR NRN GULF GATHERS STRENGTH. AIRMASS
WL CONTINUE TO BE MOIST AND JUICY WITH POTENTIAL FOR LGT RAIN/DZ/FOG
THRU 06Z WED. BY 12Z EXPECT H5 LOW WL EXTND ACRS THE CNTR PART OF
THE NATION WITH ~997MB SFC LOW LOCATED IN VICINITY OF OH VLY. THIS
WL ALLOW DEEP LYR MOISTURE TO MV IN FM THE SOUTH LKLY BTWN 09Z AND
12Z. THUS HV RAMPED POPS TO LKLY BY 09Z AND NR 100 POPS BY 12Z WED.
PW VALUES FM NAM AND GEFS EXPECTED TO BE BTWN 3-4 STANDARD
DEVIATIONS ABV NORMAL LATE TUE NGT. THIS LINES UP WELL WITH ALL
MODELS, INCLUDING HIRES AND 4KM NAM, SHOWING THE FIRST SURGE OF RAIN
TWD 12Z.
H5 LOW WL GO NEGATIVE ON WED WITH GOM WIDE OPEN AS 40-50KT H8 JET
PUMPS MOISTURE INTO REGION DRG THE DAY. PW VALUES DRG THE AFTN HRS
INCREASE TO 4-5 SD ABV NORMAL VALUES WITH V-COMPONENT OF H8 WINDS
RANGING FM 2-3 SD DRG THE DAY. COUPLED JET REGION OF H2 SPEED MAX
LOOKS TO BE TO THE WEST OF CWA ON WED. THAT BEING SAID, WL CONTINUE
WITH MENTION OF MODERATE RAIN FOR XMAS EVE.
FROPA LOOKS TO OCCUR ARND 09Z ON CHRISTMAS MRNG. CANNOT RULE OUT A
RUMBLE OF THUNDER IMMEDIATELY AHD OF FRONT, HWVR THINK CHCS ARE
MARGINAL SO WL NOT INLUDE IN GRIDS AT THIS TIME. AS INVERSION
BREAKS, STRONG WINDS ALOFT WL BE ABLE TO MIX DOWN AS IT MVS THRU
WITH A GUSTY SW WIND LOOKING LIKELY LATE WED NIGHT WHICH WL GIVE
SANTA A HARD TIME. LATER SHIFTS MAY NEED TO CONSIDER WIND HEADLINES
FOR LATE WED NGT INTO THURSDAY BUT STILL TOO EARLY AT THIS POINT.
TEMPS WL VRY SLOWLY FALL ON THURSDAY WITH A SLOW RAIN/SNOW MIX
WORKING IN THROUGHOUT CHRISTMAS DAY. NOT EXPECTING ANYTHING MORE
THAN A TRACE OF SNOW TO FALL ON THURSDAY WITH A DUSTING POSSIBLE ON
280-290 FLOW ACRS LK ZONES. HWVR INVERSION WL BE LOWERING DRG THE
EVNG HRS SO NOT EXPECTING MUCH IN THE WAY OF ACCUMS THRU THE END OF
THE SHORT TERM.
&&
.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 /19Z TUESDAY THROUGH SUNDAY/...
THE ONLY CONFIDENCE IN THE AVIATION FORECAST TODAY IS IN THE BROAD
GENERALITIES OF THE WEATHER PATTERN AS THE DETAILS AT EACH
AIRPORT IS SUJECT TO THE SUBTLTIES OF LOCAL TERRAIN. THE FORECAST
AREA IS WITHIN A VEERING SOUTHEAST TO SOUTHWEST FLOW FROM THE SFC-
10KFT WHICH WILL CONTINUE TO SUPPORT A STRONG TEMPERATURE
INVERSION THAT SHOULD LOCKS IN RESTRICTIVE FLIGHT CATEGORIES FOR
THE FORSEEABLE FUTURE.
THAT SAID...THE SOUTHEASTERLY FLOW IN THE LOW LEVELS WILL IMPINGE
UPON THE TERRAIN CAUSING SOME FLUCTUATION IN THE GENERAL IDEA OF
THE FORECAST. KSYR WILL BENEFIT FROM DOWNSLOPE FLOW WITH MOST OF THE REST
OF TODAY FLUCTUATING BETWEEN VFR AND MVFR. A SIMILAR STORY EXISTS
AT KAVP WHERE THE RIDGE LINE TO THE SOUTHEAST OF AIRPORT ALLOWS
VLIFR TO STICK IN THE MOUNTAINS AND MVFR TO PREVAIL RIGHT OVER THE
TERMINAL. MVFR WILL ALSO DOMINATE AT KRME...ALTHOUGH POOR CONDITIONS CAN
SNEAK...UNNANOUNCED UP THE MOHAWK VALLEY. EVERYWHERE ELSE...IFR
IS EXPECTED AT KELM/KBGM AND CAN BE IN AND OUT AT KITH AS TERRAIN
FLOW CHANGES.
HIGH-REZ MODELS ALL SUGGEST THAT AS WARM ADVECTION STRENGTHENS
THIS EVENING...THE CHANCE FOR DRIZZLE WILL INCREASE AND CIGS/VSBYS
WILL LOWER A CATEGORY OR TWO AT ALL STATIONS TONIGHT WITH THE
DOMINANT FLIGHT CATEGORY BEING IFR WITH FUEL ALTERNATES NECESSARY
AT SOME SITES. DON/T THINK WE WILL BE SHUTTING DOWN TO AIRPORT
MINS ANYWHERE...BUT MAY COME CLOSE AT TIMES. THE MAIN BULK OF RAIN
ALONG WITH THE WORST CONDITIONS IS EXPECTED TO ARRIVE FROM SW-NE
WELL AFTER MIDNIGHT WITH WIDESPREAD IFR/VLIFR/FUEL ALTS EXPECTED
INTO WEDNESDAY.
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...PVF
LONG TERM...JAB
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
137 PM EST TUE DEC 23 2014
.SYNOPSIS...
LIGHT RAIN AND PATCHY DRIZZLE WILL CONTINUE THIS AFTERNOON AND
EVENING AS A WEAK SURFACE LOW MOVES UP THE EAST COAST. A STRONGER
STORM SYSTEM MOVING UP FROM THE GULF OF MEXICO WILL BRING A MORE
WIDESPREAD RAIN TO CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA
LATE TONIGHT THROUGH EARLY CHRISTMAS MORNING. A STRONG FRONT WILL
MOVE THROUGH CHRISTMAS MORNING BRINGING STRONG GUSTY WINDS TO THE
AREA, WITH LINGERING RAIN SHOWERS MIXING WITH SNOW SHOWERS.
&&
.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 THURSDAY NIGHT/...
335 AM UPDATE...
CWA WL BE IN A LULL THE FIRST PART OF TONIGHT AS SFC LOW ALONG THE
ERN SEABOARD FILLS AND SYSTEM OVR NRN GULF GATHERS STRENGTH. AIRMASS
WL CONTINUE TO BE MOIST AND JUICY WITH POTENTIAL FOR LGT RAIN/DZ/FOG
THRU 06Z WED. BY 12Z EXPECT H5 LOW WL EXTND ACRS THE CNTR PART OF
THE NATION WITH ~997MB SFC LOW LOCATED IN VICINITY OF OH VLY. THIS
WL ALLOW DEEP LYR MOISTURE TO MV IN FM THE SOUTH LKLY BTWN 09Z AND
12Z. THUS HV RAMPED POPS TO LKLY BY 09Z AND NR 100 POPS BY 12Z WED.
PW VALUES FM NAM AND GEFS EXPECTED TO BE BTWN 3-4 STANDARD
DEVIATIONS ABV NORMAL LATE TUE NGT. THIS LINES UP WELL WITH ALL
MODELS, INCLUDING HIRES AND 4KM NAM, SHOWING THE FIRST SURGE OF RAIN
TWD 12Z.
H5 LOW WL GO NEGATIVE ON WED WITH GOM WIDE OPEN AS 40-50KT H8 JET
PUMPS MOISTURE INTO REGION DRG THE DAY. PW VALUES DRG THE AFTN HRS
INCREASE TO 4-5 SD ABV NORMAL VALUES WITH V-COMPONENT OF H8 WINDS
RANGING FM 2-3 SD DRG THE DAY. COUPLED JET REGION OF H2 SPEED MAX
LOOKS TO BE TO THE WEST OF CWA ON WED. THAT BEING SAID, WL CONTINUE
WITH MENTION OF MODERATE RAIN FOR XMAS EVE.
FROPA LOOKS TO OCCUR ARND 09Z ON CHRISTMAS MRNG. CANNOT RULE OUT A
RUMBLE OF THUNDER IMMEDIATELY AHD OF FRONT, HWVR THINK CHCS ARE
MARGINAL SO WL NOT INLUDE IN GRIDS AT THIS TIME. AS INVERSION
BREAKS, STRONG WINDS ALOFT WL BE ABLE TO MIX DOWN AS IT MVS THRU
WITH A GUSTY SW WIND LOOKING LIKELY LATE WED NIGHT WHICH WL GIVE
SANTA A HARD TIME. LATER SHIFTS MAY NEED TO CONSIDER WIND HEADLINES
FOR LATE WED NGT INTO THURSDAY BUT STILL TOO EARLY AT THIS POINT.
TEMPS WL VRY SLOWLY FALL ON THURSDAY WITH A SLOW RAIN/SNOW MIX
WORKING IN THROUGHOUT CHRISTMAS DAY. NOT EXPECTING ANYTHING MORE
THAN A TRACE OF SNOW TO FALL ON THURSDAY WITH A DUSTING POSSIBLE ON
280-290 FLOW ACRS LK ZONES. HWVR INVERSION WL BE LOWERING DRG THE
EVNG HRS SO NOT EXPECTING MUCH IN THE WAY OF ACCUMS THRU THE END OF
THE SHORT TERM.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
1 AM UPDATE...
LITTLE CHANGE. FOLLOWED WPC GUIDANCE. FRI/FRI NGT DRY THEN RAIN
MOVES BACK IN LATE SAT THEN CHANGES TO SNOW FROM NW TO SE SUN AND
SUN NGT. MOSTLY DRY MON/TUE. TEMPERATURES ABOVE NORMAL FALLING TO
NORMAL MON/TUE.
PREVIOUS DISCUSSION...
STRONG COLD FRONT PASSES THE REGION THURSDAY MORNING. MODELS ARE
IN REASONABLE AGREEMENT WITH THIS FEATURE AND SUGGEST THE MOST
SIGNIFICANT IMPACT WILL BE SW-W WINDS IN THE STRONG COLD ADVECTION
THURSDAY AFTERNOON. WINDS MAY GUST AT TIMES 35-45 MPH. THERE IS
ALSO A GOOD SIGNAL SHOWING UP FOR A NARROW COLD FRONTAL RAIN BAND
PHENOMENA MOVING THROUGH BETWEEN 12Z-18Z. THIS FEATURE ALONE MAY
CAUSE CONVECTIVE WIND ACCELERATIONS AND SCATTERED DAMAGE/POWER
OUTAGES. LOOKING FOR A NON-DIURNAL TEMPERATURE TREND FROM WEDS
NIGHT-THURSDAY WITH MAXES FOR WEDS/THURS PROBABLY A FEW HOURS
EITHER SIDE OF MIDNIGHT AS STRONG WARM SECTOR SURGES INTO AREA.
OUTSIDE OF THIS FEATURE...THE TEMPERATURES ARE TRENDING SLIGHTLY
WARMER SO A CHANGEOVER FROM PERIODS OF RAIN TO SCATTERED RAIN/SNOW
SHOWERS SEEMS MORE LIKELY THAN A SHARP TURNOVER TO ALL SNOW. IN
FACT...A SIGNIFICANT DRY SLOT MAY CUT PRECIPITATION OFF FOR MUCH
OF THE MORNING BEFORE THE INSTABILITY SHOWERS ASSOCIATED WITH THE
COLD POOL KICK IN FOR THURSDAY AFTERNOON AND NIGHT.
THE REMAINDER OF THE WEEK FEATURES SOME WEAK LAKE EFFECT RESPONSE
MAINLY NORTH OF CENTRAL NY ON FRIDAY...THEN RIDGING AND GENERALLY
NEAR TO ABOVE NORMAL TEMPERATURES INTO SATURDAY. BIG MODEL
DISCREPANCIES THEN CONTINUE TO SHOW UP BETWEEN THE ECMWF AND GFS
WHERE THE ECMWF BRINGS A QUICK TN VALLEY RUNNER TO THE MIDDLE
ATLANTIC COAST BY SUNDAY AFTERNOON. THE GFS AND GEFS ENSEMBLES
FEATURE A MUCH FLATTER SWLY FLOW AND SFC HIGH PRESSURE. THE
CANADIAN GGEM DEFINITELY LEANS WITH THE EURO WITH LOW PRES ON THE
COAST SUNDAY AFTERNOON. AT THIS TIME...WILL BLANKET WITH LOW CHC
POPS FOR SNOW SHOWERS GIVEN THE HIGH LVL OF UNCERTAINTY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THE ONLY CONFIDENCE IN THE AVIATION FORECAST TODAY IS IN THE BROAD
GENERALITIES OF THE WEATHER PATTERN AS THE DETAILS AT EACH
AIRPORT IS SUJECT TO THE SUBTLTIES OF LOCAL TERRAIN. THE FORECAST
AREA IS WITHIN A VEERING SOUTHEAST TO SOUTHWEST FLOW FROM THE SFC-
10KFT WHICH WILL CONTINUE TO SUPPORT A STRONG TEMPERATURE
INVERSION THAT SHOULD LOCKS IN RESTRICTIVE FLIGHT CATEGORIES FOR
THE FORSEEABLE FUTURE.
THAT SAID...THE SOUTHEASTERLY FLOW IN THE LOW LEVELS WILL IMPINGE
UPON THE TERRAIN CAUSING SOME FLUCTUATION IN THE GENERAL IDEA OF
THE FORECAST. KSYR WILL BENEFIT FROM DOWNSLOPE FLOW WITH MOST OF THE REST
OF TODAY FLUCTUATING BETWEEN VFR AND MVFR. A SIMILAR STORY EXISTS
AT KAVP WHERE THE RIDGE LINE TO THE SOUTHEAST OF AIRPORT ALLOWS
VLIFR TO STICK IN THE MOUNTAINS AND MVFR TO PREVAIL RIGHT OVER THE
TERMINAL. MVFR WILL ALSO DOMINATE AT KRME...ALTHOUGH POOR CONDITIONS CAN
SNEAK...UNNANOUNCED UP THE MOHAWK VALLEY. EVERYWHERE ELSE...IFR
IS EXPECTED AT KELM/KBGM AND CAN BE IN AND OUT AT KITH AS TERRAIN
FLOW CHANGES.
HIGH-REZ MODELS ALL SUGGEST THAT AS WARM ADVECTION STRENGTHENS
THIS EVENING...THE CHANCE FOR DRIZZLE WILL INCREASE AND CIGS/VSBYS
WILL LOWER A CATEGORY OR TWO AT ALL STATIONS TONIGHT WITH THE
DOMINANT FLIGHT CATEGORY BEING IFR WITH FUEL ALTERNATES NECESSARY
AT SOME SITES. DON/T THINK WE WILL BE SHUTTING DOWN TO AIRPORT
MINS ANYWHERE...BUT MAY COME CLOSE AT TIMES. THE MAIN BULK OF RAIN
ALONG WITH THE WORST CONDITIONS IS EXPECTED TO ARRIVE FROM SW-NE
WELL AFTER MIDNIGHT WITH WIDESPREAD IFR/VLIFR/FUEL ALTS EXPECTED
INTO WEDNESDAY.
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...PVF
LONG TERM...JAB/TAC
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1256 PM EST TUE DEC 23 2014
.SYNOPSIS...
LIGHT RAIN AND PATCHY DRIZZLE WILL CONTINUE THIS AFTERNOON AND
EVENING AS A WEAK SURFACE LOW MOVES UP THE EAST COAST. A STRONGER
STORM SYSTEM MOVING UP FROM THE GULF OF MEXICO WILL BRING A MORE
WIDESPREAD RAIN TO CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA
LATE TONIGHT THROUGH EARLY CHRISTMAS MORNING. A STRONG FRONT WILL
MOVE THROUGH CHRISTMAS MORNING BRINGING STRONG GUSTY WINDS TO THE
AREA, WITH LINGERING RAIN SHOWERS MIXING WITH SNOW SHOWERS.
&&
.NEAR TERM /THROUGH TONIGHT/...
RADARS SHOW A BAND OF RAIN LIFTING NORTHEAST INTO CENTRAL NY AND
NRN PA IN ASSCTN WITH A SHORT WAVE THAT WAS RIPPLING NORTHEASTWARD
INTO THE NE U.S. THIS FEATURE WAS SEEN AS SOME ENHANCED CLOUD TOPS
ON THE IR IMAGERY AT THIS TIME. THIS FEATURE WILL RACE OFF TO THE
NORTHEAST BY EARLY AFTERNOON AND THE RAIN WILL GO WITH IT LEAVING
BEHIND PATCHY AREAS OF LIGHT RAIN AND DRIZZLE FOR THE REST OF THE
AFTERNOON AND MUCH OF TONIGHT. A FEW PATCHES OF STEADIER RAIN CUD
ADVECT THRU THE REGION AS PER HRRR LATE AFTERNOON/EVENING. SO WILL KEEP
CHC POPS GOING FOR AFTERNOON AND MUCH OF TONIGHT TO COVER ANY
POCKETS OF LIGHT RAIN/DRIZZLE OR A BRIEF STEADIER PD OF RAIN. MAIN
SHIELD OF RAIN ARRIVES BTWN 8 AND 12Z WED AS ONE OF THE FIRST
SIGNIFICANT MAIN WAVES RIDES NORTHEASTWARD AHEAD OF THE DIGGING
TROUGH THAT DROPS INTO THE SRN U.S LATER TONIGHT. THIS WAVE WILL
ACCELERATE A SRLY LLJ WHICH ADVECTS PLENTY OF MOISTURE NORTHWARD
INTO NY AND PA AS IT GLIDES UP THE ISENTROPES LATE TONIGHT. IN
ADDTN...UPR DVRG INCREASES AS WELL. THIS IS RECIPE FOR A
WIDESPREAD AREA OF RAIN TO OVERSPREAD THE ENTIRE AREA BY 12Z WED. I
ALSO KEEP PATCHY DENSE FOG IN THE POCONOS AND CATSKILLS IN THE
HIGHER TERRAIN AS THE LL FLOW IS SERLY AND UPSLOPING UNTIL THE
HEAVIER RAIN ARRIVES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
335 AM UPDATE...
CWA WL BE IN A LULL THE FIRST PART OF TONIGHT AS SFC LOW ALONG THE
ERN SEABOARD FILLS AND SYSTEM OVR NRN GULF GATHERS STRENGTH. AIRMASS
WL CONTINUE TO BE MOIST AND JUICY WITH POTENTIAL FOR LGT RAIN/DZ/FOG
THRU 06Z WED. BY 12Z EXPECT H5 LOW WL EXTND ACRS THE CNTR PART OF
THE NATION WITH ~997MB SFC LOW LOCATED IN VICINITY OF OH VLY. THIS
WL ALLOW DEEP LYR MOISTURE TO MV IN FM THE SOUTH LKLY BTWN 09Z AND
12Z. THUS HV RAMPED POPS TO LKLY BY 09Z AND NR 100 POPS BY 12Z WED.
PW VALUES FM NAM AND GEFS EXPECTED TO BE BTWN 3-4 STANDARD
DEVIATIONS ABV NORMAL LATE TUE NGT. THIS LINES UP WELL WITH ALL
MODELS, INCLUDING HIRES AND 4KM NAM, SHOWING THE FIRST SURGE OF RAIN
TWD 12Z.
H5 LOW WL GO NEGATIVE ON WED WITH GOM WIDE OPEN AS 40-50KT H8 JET
PUMPS MOISTURE INTO REGION DRG THE DAY. PW VALUES DRG THE AFTN HRS
INCREASE TO 4-5 SD ABV NORMAL VALUES WITH V-COMPONENT OF H8 WINDS
RANGING FM 2-3 SD DRG THE DAY. COUPLED JET REGION OF H2 SPEED MAX
LOOKS TO BE TO THE WEST OF CWA ON WED. THAT BEING SAID, WL CONTINUE
WITH MENTION OF MODERATE RAIN FOR XMAS EVE.
FROPA LOOKS TO OCCUR ARND 09Z ON CHRISTMAS MRNG. CANNOT RULE OUT A
RUMBLE OF THUNDER IMMEDIATELY AHD OF FRONT, HWVR THINK CHCS ARE
MARGINAL SO WL NOT INLUDE IN GRIDS AT THIS TIME. AS INVERSION
BREAKS, STRONG WINDS ALOFT WL BE ABLE TO MIX DOWN AS IT MVS THRU
WITH A GUSTY SW WIND LOOKING LIKELY LATE WED NIGHT WHICH WL GIVE
SANTA A HARD TIME. LATER SHIFTS MAY NEED TO CONSIDER WIND HEADLINES
FOR LATE WED NGT INTO THURSDAY BUT STILL TOO EARLY AT THIS POINT.
TEMPS WL VRY SLOWLY FALL ON THURSDAY WITH A SLOW RAIN/SNOW MIX
WORKING IN THROUGHOUT CHRISTMAS DAY. NOT EXPECTING ANYTHING MORE
THAN A TRACE OF SNOW TO FALL ON THURSDAY WITH A DUSTING POSSIBLE ON
280-290 FLOW ACRS LK ZONES. HWVR INVERSION WL BE LOWERING DRG THE
EVNG HRS SO NOT EXPECTING MUCH IN THE WAY OF ACCUMS THRU THE END OF
THE SHORT TERM.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
1 AM UPDATE...
LITTLE CHANGE. FOLLOWED WPC GUIDANCE. FRI/FRI NGT DRY THEN RAIN
MOVES BACK IN LATE SAT THEN CHANGES TO SNOW FROM NW TO SE SUN AND
SUN NGT. MOSTLY DRY MON/TUE. TEMPERATURES ABOVE NORMAL FALLING TO
NORMAL MON/TUE.
PREVIOUS DISCUSSION...
STRONG COLD FRONT PASSES THE REGION THURSDAY MORNING. MODELS ARE
IN REASONABLE AGREEMENT WITH THIS FEATURE AND SUGGEST THE MOST
SIGNIFICANT IMPACT WILL BE SW-W WINDS IN THE STRONG COLD ADVECTION
THURSDAY AFTERNOON. WINDS MAY GUST AT TIMES 35-45 MPH. THERE IS
ALSO A GOOD SIGNAL SHOWING UP FOR A NARROW COLD FRONTAL RAIN BAND
PHENOMENA MOVING THROUGH BETWEEN 12Z-18Z. THIS FEATURE ALONE MAY
CAUSE CONVECTIVE WIND ACCELERATIONS AND SCATTERED DAMAGE/POWER
OUTAGES. LOOKING FOR A NON-DIURNAL TEMPERATURE TREND FROM WEDS
NIGHT-THURSDAY WITH MAXES FOR WEDS/THURS PROBABLY A FEW HOURS
EITHER SIDE OF MIDNIGHT AS STRONG WARM SECTOR SURGES INTO AREA.
OUTSIDE OF THIS FEATURE...THE TEMPERATURES ARE TRENDING SLIGHTLY
WARMER SO A CHANGEOVER FROM PERIODS OF RAIN TO SCATTERED RAIN/SNOW
SHOWERS SEEMS MORE LIKELY THAN A SHARP TURNOVER TO ALL SNOW. IN
FACT...A SIGNIFICANT DRY SLOT MAY CUT PRECIPITATION OFF FOR MUCH
OF THE MORNING BEFORE THE INSTABILITY SHOWERS ASSOCIATED WITH THE
COLD POOL KICK IN FOR THURSDAY AFTERNOON AND NIGHT.
THE REMAINDER OF THE WEEK FEATURES SOME WEAK LAKE EFFECT RESPONSE
MAINLY NORTH OF CENTRAL NY ON FRIDAY...THEN RIDGING AND GENERALLY
NEAR TO ABOVE NORMAL TEMPERATURES INTO SATURDAY. BIG MODEL
DISCREPANCIES THEN CONTINUE TO SHOW UP BETWEEN THE ECMWF AND GFS
WHERE THE ECMWF BRINGS A QUICK TN VALLEY RUNNER TO THE MIDDLE
ATLANTIC COAST BY SUNDAY AFTERNOON. THE GFS AND GEFS ENSEMBLES
FEATURE A MUCH FLATTER SWLY FLOW AND SFC HIGH PRESSURE. THE
CANADIAN GGEM DEFINITELY LEANS WITH THE EURO WITH LOW PRES ON THE
COAST SUNDAY AFTERNOON. AT THIS TIME...WILL BLANKET WITH LOW CHC
POPS FOR SNOW SHOWERS GIVEN THE HIGH LVL OF UNCERTAINTY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THE ONLY CONFIDENCE IN THE AVIATION FORECAST TODAY IS IN THE BROAD
GENERALITIES OF THE WEATHER PATTERN AS THE DETAILS AT EACH
AIRPORT IS SUJECT TO THE SUBTLTIES OF LOCAL TERRAIN. THE FORECAST
AREA IS WITHIN A VEERING SOUTHEAST TO SOUTHWEST FLOW FROM THE SFC-
10KFT WHICH WILL CONTINUE TO SUPPORT A STRONG TEMPERATURE
INVERSION THAT SHOULD LOCKS IN RESTRICTIVE FLIGHT CATEGORIES FOR
THE FORSEEABLE FUTURE.
THAT SAID...THE SOUTHEASTERLY FLOW IN THE LOW LEVELS WILL IMPINGE
UPON THE TERRAIN CAUSING SOME FLUCTUATION IN THE GENERAL IDEA OF
THE FORECAST. KSYR WILL BENEFIT FROM DOWNSLOPE FLOW WITH MOST OF THE REST
OF TODAY FLUCTUATING BETWEEN VFR AND MVFR. A SIMILAR STORY EXISTS
AT KAVP WHERE THE RIDGE LINE TO THE SOUTHEAST OF AIRPORT ALLOWS
VLIFR TO STICK IN THE MOUNTAINS AND MVFR TO PREVAIL RIGHT OVER THE
TERMINAL. MVFR WILL ALSO DOMINATE AT KRME...ALTHOUGH POOR CONDITIONS CAN
SNEAK...UNNANOUNCED UP THE MOHAWK VALLEY. EVERYWHERE ELSE...IFR
IS EXPECTED AT KELM/KBGM AND CAN BE IN AND OUT AT KITH AS TERRAIN
FLOW CHANGES.
HIGH-REZ MODELS ALL SUGGEST THAT AS WARM ADVECTION STRENGTHENS
THIS EVENING...THE CHANCE FOR DRIZZLE WILL INCREASE AND CIGS/VSBYS
WILL LOWER A CATEGORY OR TWO AT ALL STATIONS TONIGHT WITH THE
DOMINANT FLIGHT CATEGORY BEING IFR WITH FUEL ALTERNATES NECESSARY
AT SOME SITES. DON/T THINK WE WILL BE SHUTTING DOWN TO AIRPORT
MINS ANYWHERE...BUT MAY COME CLOSE AT TIMES. THE MAIN BULK OF RAIN
ALONG WITH THE WORST CONDITIONS IS EXPECTED TO ARRIVE FROM SW-NE
WELL AFTER MIDNIGHT WITH WIDESPREAD IFR/VLIFR/FUEL ALTS EXPECTED
INTO WEDNESDAY.
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/PVF
NEAR TERM...DJN
SHORT TERM...PVF
LONG TERM...JAB/TAC
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
232 PM EST TUE DEC 23 2014
.SYNOPSIS...A COLD AIR DAMMING RIDGE WILL REMAIN LOCKED IN PLACE
EAST OF THE APPALACHIANS THROUGH THIS EVENING. A WARM FRONT WILL
LIFT NORTHWARD THROUGH THE AREA WEDNESDAY MORNING AS A LOW PRESSURE
SYSTEM STRENGTHENS WEST OF THE MOUNTAINS. AN ASSOCIATED COLD FRONT
WILL SURGE EASTWARD ACROSS THE CAROLINAS WEDNESDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 PM TUESDAY...
CAD WEDGE REMAINS STRONGLY ANCHORED IN PLACE AS EVIDENT FROM THE
VERY STRONG INVERSION ON THE CURRENT RAP FORECAST SOUNDINGS. THIS
DOES NOT CHANGE HARDLY AT ALL OVERNIGHT AND SO THE FOG/MIST AND LOW
CEILINGS WILL ALSO CONTINUE THROUGH TONIGHT. AFTER 00Z A WARM FRONT
WILL BEGIN ITS NORTHWARD ADVANCEMENT THROUGH OUR CWA AND WITH IT
WILL COME A PERIOD OF RAIN BEGINNING ABOUT 00Z IN THE SOUTH AND A
COUPLE HOURS LATER IN THE NORTH. THIS FIRST BOUT OF RAIN WILL LAST
UNTIL 6-8Z BEFORE HIGH RESOLUTION MODELS PREDICT A LULL IN
PRECIPITATION. DURING THIS LULL EXPECT FOG TO BECOME AN ISSUE WITH
AREAS OF 1/2 SM VISIBILITIES AND PROBABLY LESS IN SOME SPOTS. WOULD
NOT BE SURPRISED TO HAVE TO ISSUE A DENSE FOG ADVISORY SOMETIME
AFTER 6Z THROUGH DAYBREAK FOR THE ENTIRE AREA. A SECOND WAVE OF
PRECIPITATION WILL APPROACH THE AREA FROM THE SOUTHWEST CLOSER TO
DAYBREAK. THIS AGAIN IS ACCORDING TO HIGH RESOLUTION
MODELS...WHEREAS THE GFS AND ECMWF HAVE A MORE CONTINUOUS
PRECIPIATION PATTERN OVERNIGHT. HAVE HEDGED THE FORECAST TOWARDS THE
HIGH RES MODELS. EARLIER INDICATIONS WERE THAT SOME ELEVATED
INSTABILITY MIGHT CREATE ENOUGH LIFT FOR SOME THUNDERSTORMS THIS
EVENING. WHILE CURRENT SHORT TERM MODELS ARE STILL SHOWING DECENT
MID LEVEL LAPSE RATES FOR THIS TIME OF YEAR...THEY ARE LACKING THE
INSTABILITY THAT WAS THERE IN THIS MORNINGS RUN. AS A RESULT HAVE
TAKEN MENTION OF THUNDER OUT OF THE FORECAST FOR NOW. RADAR IS
HOWEVER DEPICTING SOME LIGHTNING STRIKES IN THE CHARLOTTE AREA AND
DOWN ALONG THE COAST SOUTH OF WILMINGTON. TRENDS IN THE ACTIVITY
OVER THE PAST HOUR OR SO ARE WEAKENING SO WHILE IT IS NOT IMPOSSIBLE
THAT WE WILL SEE A LIGHTNING STRIKE OR TWO...THE CHANCES ARE GETTING
LESS LIKELY.
TEMPERATURES WILL FOLLOW A NON-DIURNAL PATTERN THIS EVENING INTO THE
OVERNIGHT HOURS AS THE WARM FRONT MOVES NORTH...EXPECT TEMPERATURES
TO RISE OVERNIGHT...AND LOWS ARE MOST LIKELY TO OCCUR DURING THE
EVENING HOURS TONIGHT IN THE LOW TO MID 40S BEFORE RISING OVERNIGHT.
THE WARMING TREND WILL BE VERY MUTED IN THE TRIAD WHERE THE WARM AIR
WILL END UP RISING UP OVER THE COLD DOME LOCKED IN BY THE CAD WEDGE.
THEREFORE EXPECT LOW 40S IN THE TRIAD NEAR DAYBREAK WITH MUCH WARMER
MID TO UPPER 50S IN THE SOUTH AND EAST. THE PROGRESSION OF
TEMPERATURES WILL DEPEND ON THE FRONTAL ADVANCEMENT AND THEREFORE
HOURLY TEMPERATURES OVERNIGHT ARE A LOW CONFIDENCE FORECAST AT BEST.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 200 PM TUESDAY...
...ACTIVE WEATHER DAY ON TAP WITH CAD...HEAVY RAIN AND A SMALL
THREAT OF SEVERE WEATHER IN THE COASTAL PLAIN...
NWP GUIDANCE IS IN GOOD AGREEMENT WITH THE OVERALL EVOLUTION OF THE
WEATHER PATTERN DURING THE SHORT TERM PERIOD WITH A HIGH AMPLITUDE
DIGGING TROUGH AT 500 HPA THAT EXTENDS INTO THE WESTERN GULF OF
MEXICO AT DAYBREAK WEDNESDAY. THE TROUGH CLOSES OFF WITH AN UPPER
LOW DURING THE MORNING AS IT LIFTS FROM NEAR KSTL TO NORTHEAST OF
KDET TOWARD MIDNIGHT AS THE TROUGH AXIS SLOWLY SHIFTS EAST TO NEAR
OR JUST WEST OF THE APPALACHIANS BY DAYBREAK CHRISTMAS MORNING. AT
THE SURFACE...AN AREA OF LOW PRESSURE DEVELOPING IN THE LOWER OH
VALLEY RAPIDLY DEEPENS AS IT MOVES TO NORTH OF THE GREAT LAKES AFTER
MIDNIGHT. THE ATTENDANT COLD FRONT REACHES THE SOUTHWESTERN
APPALACHIANS AROUND MIDDAY WEDNESDAY...THE TRIANGLE TOWARD MIDNIGHT
AND THE COAST BY DAYBREAK CHRISTMAS MORNING.
AFTER AFTER A PREDAWN LULL...WIDESPREAD RAIN WITH EMBEDDED HEAVIER
SHOWERS WILL OVERSPREAD CENTRAL NC AFTER DAYBREAK FROM THE SOUTHWEST
AS A WARM FRONT LIFTS NORTH THROUGH THE REGION. THE RAIN WILL
OVERWHELM MUCH OF CENTRAL NC DURING THE MORNING INTO THE EARLY
AFTERNOON HOURS. GUIDANCE DIFFERS IN THE HANDLING OF THE DETAILS OF
THE PRECIPITATION WITH THE CONVECTION ALLOWING MODELS (CAMS)
SUGGESTING THE CONVECTION WILL OUTRUN THE COLD FRONT AND THE LAGGING
UPPER TROUGH WITH THE LINE OF CONVECTION REACHING THE COASTAL PLAIN
TOWARD MID/LATE AFTERNOON WITH A LULL BEHIND THE LINE. OTHER
CONVECTION PARAMETERIZED MODELS SHOW A MORE OR LESS CONTINUOUS
PERIOD OF PRECIPITATION THROUGH THE LATE NIGHT HOURS. FEEL THE CAMS
DEPICT THE EVOLUTION OF THE EVENT MORE REALISTICALLY AND WILL USE
THEM TO CONSTRUCT THE GRIDS AND HIGHLIGHT A BAND OF HEAVIER SHOWERS
AND THUNDERSTORMS. PRECIPITATION CHANCES WILL DECREASE DURING THE
EVENING IN A RELATIVE LULL BETWEEN THE DEPARTING SQUALL LINE AND THE
APPROACHING UPPER TROUGH. GUIDANCE HAS TRENDED SLOWER WITH THE
PASSAGE OF THE COLD FRONT AND THE UPPER TROUGH AND SUGGEST ANOTHER
LINE OF SHOWERS WILL LIKELY REDEVELOP IN THE WESTERN PIEDMONT JUST
PRIOR TO MIDNIGHT AND EXPAND IN COVERAGE AND INTENSITY AS IT MOVES
EAST AND REACHES THE COASTAL PLAIN WELL AFTER MIDNIGHT.
THE THREAT FOR SEVERE CONVECTION WED AFTERNOON IS LIMITED IN CENTRAL
NC BUT HAS BEEN TRENDING UPWARD SLIGHTLY. THE AMOUNT OF BOUNDARY
LAYER DESTABILIZATION IS STILL RATHER SMALL BUT THE MOST RECENT RUN
OF THE SREF SHOWS ALL 21 MEMBERS WITH AT LEAST SOME SFC CAPE AT 18-
20Z AT KFAY WITH NEARLY HALF OF THE MEMBERS SHOWING CAPE VALUES
GREATER THAN 250 UNITS. THESE ARE STILL PRETTY MEAGER VALUES BUT
THEY HAVE BEEN TRENDING UPWARD AND COMBINED WITH BULK SHEAR VALUES
AROUND 50KTS...A LIMITED THREAT OF SEVERE WEATHER IS PRESENT IN THE
COASTAL PLAIN AND SANDHILLS DURING THE MID TO LATE AFTERNOON HOURS
WEDNESDAY. FURTHER NORTH AND WEST THE BOUNDARY LAYER IS MORE STABLE
SO CONVECTION IS LIKELY TO INTENSIFY NOTABLY AS IT PUSHES EAST OF
U.S. 1.. MODEL CONSENSUS EXPERIMENTAL SHERB HSLC VALUES ARE ELEVATED
IN THE 0.7 TO 0.9 RANGE AT 18Z ON WEDNESDAY IN THE EASTERN PIEDMONT
AND SOUTHERN COASTAL PLAIN OF NC...NEAR BUT LESS THAN THE CRITICAL
VALUE OF 1. THE LIMITING FACTOR IN ADDITION TO INSTABILITY IS THE
LAGGING UPPER TROUGH AND ITS HEIGHTS FALLS AND INCREASED LAPSE
RATES.
AS IS TYPICALLY THE CASE...THE INSITU COLD AIR DAMMING WILL PERSIST
IN THE NORTHWEST PIEDMONT LONGER THAN MOST OF THE NWP GUIDANCE
SUGGESTS...ALTHOUGH THE HIGH RES WINDOW SIMULATIONS HOLD ONTO COOLER
TEMPS LONGER COMPARED TO THE NAM/GFS/EC. EVENTUALLY THE APPROACHING
COLD FRONT WILL SCOUR OUT THE CAD AIRMASS IN THE TRIAD BUT THE
ASSOCIATED MIXING WILL ACTUALLY PRODUCE A WINDOW OF WARMING
TEMPERATURES DURING THE EVENING THROUGH MIDNIGHT.
ELSEWHERE...TEMPERATURES WILL RISE INTO THE 60S WITH SOME LOWER 70S
IN THE SANDHILLS AND SOUTHERN COASTAL PLAIN BY AFTERNOON.
STILL SOME CONCERN FOR THE POTENTIAL OF FLASH FLOODING AND EVENTUAL
MINOR RIVER FLOODING BUT THE PRECIPITATION IS LIKELY TO ARRIVE IN
MULTIPLE WAVES DURING THE PERIOD. IN ADDITION...TIME LAGGED
ENSEMBLES FOR BOTH THE NAM AND GFS SUGGEST RECENT RUNS ARE TRENDING
WITH LOWER QPF...GENERALLY RANGING BETWEEN 1.0 AND 1.5 INCHES. A
MORE GENERAL URBAN AND SMALL STREAM THREAT SEEMS MOST PROBABLE AT
THIS POINT. SEE HYDRO DISCUSSION BELOW FOR MORE DETAILS. -BLAES
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 215 PM MONDAY...
THURSDAY AND THURSDAY NIGHT: 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.
FRIDAY THROUGH SATURDAY: DRY CONDITIONS WILL PERSIST WITH ABOVE
NORMAL TEMPERATURES THROUGH SATURDAY AS HIGH PRESSURE OVER THE THE
GULF COAST STATES BUILDS OVER THE AREA ON FRIDAY...WITH LIGHT SWLY
RETURN FLOW ON SATURDAY AS THE HIGH CENTER SHIFTS OFFSHORE. HIGHS
RANGING FROM THE UPPER 50S NW TO MID 60S SE. LOWS FRIDAY NIGHT IN
THE LOWER TO MID 30S.
SATURDAY NIGHT THROUGH TUESDAY: WHILE THE NEXT TROUGH/SYSTEM TO
IMPACT THE REGION IS NOT COMPLETELY RESOLVED YET...THERE IS AT LEAST
A GENERAL CONSENSUS THAT IT WILL BE A WET LATTER HALF OF THE
WEEKEND/EARLY NEXT WEEK.
ANOTHER BATCH OF PACIFIC SHORTWAVE ENERGY IS FORECAST TO EMERGE FROM
THE SOUTHERN ROCKIES ON SATURDAY AND IS PROGGED TO PROGRESS EASTWARD
INTO THE SOUTHERN PLAINS/ARKLATEX REGION SATURDAY NIGHT AND INTO
SUNDAY...EVENTUALLY DAMPENING AS IT ROUNDS THE BASE OF THE LONG WAVE
TROUGH AND MOVES INTO THE REGION LATE SUNDAY-MONDAY. IN
RESPONSE...WEAK SFC CYCLOGENESIS ENSUES ON THE SOUTHERN END OF A
COLD FRONT...INVOF THE LOWER MS VALLEY...THAT WILL EVENTUALLY RIDE
NORTHEASTWARD TOWARDS THE SOUTHERN MID-ATLANTIC REGION...SUPPORTING
WHAT COULD END BEING ANOTHER SIGNIFICANT WIDESPREAD RAIN EVENT FOR
THE CAROLINAS SUNDAY-SUNDAY NIGHT. IN SHORT...THE MORE
AMPLIFIED/PHASED EC SOLUTION WOULD SUPPORT A SLOWER MORE CONVECTIVE
RAINFALL SCENARIO AS THE AREA OF LOW PRESSURE TRACKS THROUGH THE
SOUTHERN APPALACHIANS. THE MORE PROGRESSIVE GFS DEPICTS YET ANOTHER
OVERRUNNING DAMMING EVENT IN THE WAKE OF AN EARLIER NORTHERN STREAM
COLD FRONTAL PASSAGE SATURDAY NIGHT AS AN AREA OF LOW PRESSURE
TRACKS FROM THE NORTHERN GULF TO OFF THE SOUTHEAST COAST. GIVEN
THESE LARGE MODEL DIFFERENCES..FORECAST WILL REFLECT A
MODEL/ENSEMBLE BLEND WITH CHANCE POPS SUNDAY AND SUNDAY NIGHT WITH
NO P-TYPE CONCERNS. TEMPERATURES DROPPING BACK TO NEAR NORMAL GIVEN
WIDESPREAD RAIN AND CLOUDS.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AS OF 100 PM TUESDAY...
24 HOUR TAF PERIOD: HIGH CONFIDENCE OF LIFR OR WORSE CONDITIONS
THROUGH THE END OF THE TAF PERIOD. CONDITIONS THIS AFTERNOON HAVE
BEEN VARIABLE AS FAR AS VISIBILITIES GO...RANGING FROM 1/4 SM UP TO
AS HIGH AS 5SM BUT THE COMMON DENOMINATOR HAS BEEN VERY LOW CEILINGS
BELOW 500 FEET. THIS SHOULD CONTINUE THROUGH THE TAF PERIOD. WINDS
THIS AFTERNOON ARE FAIRLY CALM BUT WILL BE LIGHT AND VARIABLE
OVERNIGHT SHIFTING TO A MORE SOUTHERLY DIRECTION BY WEDNESDAY
AFTERNOON. LATE IN THE TAF PERIOD WIND SPEEDS COULD PICK UP TO NEAR
10 KTS. NOT MUCH PRECIPITATION IN THE AREA OTHER THAN MIST OR
DRIZZLE RIGHT NOW BUT THAT WILL CHANGE THIS EVENING AS RAIN WILL
MOVE UP FROM THE SOUTHWEST AND WILL BEGIN TO AFFECT TAF SITES AROUND
00Z WITH KRDU AND KRWI A COUPLE OF HOURS LATER. THIS FIRST ROUND OF
RAIN WILL LAST UNTIL ABOUT 6-8Z AND THEN THERE IS EXPECTED TO BE A
LULL IN PRECIPIATION. DURING THIS LULL...EXPECT WIDESPREAD FOG
ACROSS THE CWA WITH VISIBILITIES AS LEAST AS LOW AS 1/2 A MILE BUT
WOULD COUNT ON SOME AREAS OF DENSE FOG OF LESS THAN A 1/4 MILE
VISIBILITY. AROUND DAYBREAK...A SECOND ROUND OF PRECIPITATION IS
PROGGED TO MOVE INTO THE AREA WHICH MAY HELP IMPROVE VISIBILITIES A
LITTLE BUT CEILINGS WILL STILL BE BELOW 500 FEET.
LONG TERM: PERIODS OF PRECIPITATION...AND ADVERSE AVIATION
CONDITIONS WILL PERSIST THROUGH WEDNESDAY NIGHT INTO THURSDAY
MORNING BEFORE MOVING OFF TO THE EAST. THE NEXT CHANCE AFTER THAT
FOR ADVERSE CONDITIONS WILL BE WITH A SOUTHERN STREAM SYSTEM THAT
WILL MOVE INTO CENTRAL NC FOR SUNDAY INTO MONDAY.
&&
.HYDROLOGIC DISCUSSION /TONIGHT 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...ELLIS
SHORT TERM...BLAES
LONG TERM...CBL
AVIATION...ELLIS
HYDROLOGY...MLM/BADGETT
AREA FORECAST DISCUSSION
NWS BISMARCK ND
248 PM CST TUE DEC 23 2014
.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 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 245 PM CST TUE DEC 23 2014
LIGHT SNOW CONTINUES TO DIMINISH ACROSS WESTERN AND CENTRAL NORTH
DAKOTA. A BRIEF PERIOD OF FLURRIES IS STILL POSSIBLE FROM MINOT TO
BISMARCK AND JAMESTOWN...BUT ANY IMPACTS SHOULD BE MINIMAL.
CEILINGS HAVE GENERALLY TRENDED TO MVFR...AND WENT WITH A FAIRLY
OPTIMISTIC OUTLOOK OVERNIGHT WITH SUGGESTIONS THAT THE MVFR MAY
LIFT TO VFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CK
LONG TERM...MM
AVIATION...CK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
104 PM EST TUE DEC 23 2014
.SYNOPSIS...
LOW PRESSURE OVER NORTHEASTERN IOWA WILL WEAKEN AS IT MOVES TO THE
NORTHEAST THROUGH THE AFTERNOON. A SECONDARY AREA OF LOW PRESSURE
WILL DEVELOP NEAR THE GULF COAST TODAY AND UNDERGO RAPID DEEPENING
AS IT TRACKS NORTH TOWARDS LAKE ERIE BY WEDNESDAY NIGHT. THIS
SYSTEM WILL PULL A STRONG COLD FRONT ACROSS THE AREA WITH GUSTY
WINDS LATE WEDNESDAY AND WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AT THIS POINT HAVE ONLY MADE MINOR CHANGES TO THE GRIDS TO REFLECT
CURRENT CONDITIONS.
70 KNOT 5H JET IS NOSING INTO SOUTHERN OHIO WHICH SHOULD CONTINUE
TO PROVIDE SOME LIFT ACROSS THE SOUTHEASTERN THIRD OF THE COUNTY
WARNING AREA. HAVE EITHER SCATTERED OR LIKELY WORDING FOR THIS
REGION. STILL CANT RULE OUT A FEW SHOWERS ELSEWHERE SO KEPT A
CHANCE GOING.
PREVIOUS DISCUSSION...
A WARM FRONT WILL BE MOVING NORTH OF THE AREA TODAY. THE BEST
CHANCE OF SHOWERS WILL BE EARLY THIS MORNING AND THEN LATE THIS
AFTERNOON ACCORDING TO THE HRRR MODEL THAT THE NEXT ROUND OF
SHOWERS WILL BE HEADING TOWARD THE AREA. SOME QUESTION IN THIS BUT
IT SEEMS REASONABLE WITH THE TROF ASSOCIATED WITH THE LOW WILL BE
MOVING UP. EVEN BETWEEN THE SYSTEMS BATCHES OF RAIN THE AREA WILL
BE IN THE LFQ OF THE JET SO A THREAT OF SHOWERS WILL EXIST.
WITH THE WARM FRONT MOVING NORTH AND EVEN WITH PLENTY OF CLOUDS
AND SOME WIND WENT TOWARD THE WARMER GUIDANCE FOR THE HIGHS BASED
ON WARM AIR COMING UP FROM THE SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
WET AT TIMES THE NEXT FEW DAYS...ABOVE NORMAL TEMPERATURES AND
BECOMING WINDY LATE CHRISTMAS EVE.
MORE SHOWERS WILL BE MOVING THROUGH AHEAD OF THE LOW THAT WILL
MOVE ALONG THE OHIO AND INDIANA BORDER ON WEDNESDAY. SOME QUESTION
HOW MUCH SHOWER ACTIVITY WILL OCCUR ON THE WARM SIDE OF THE LOW.
KEPT HIGH POPS. WE COULD GET INTO A BREAK FROM THE SHOWERS
WEDNESDAY AFTERNOON AS THE FIRST FRONT MOVES THROUGH AND THEN
ANOTHER FRONT WEDNESDAY NIGHT...THAT FRONT MAY HAVE SOME SNOW WITH
IT. THE GFS MOS GUIDANCE SAYS IT WILL BE ALL RAIN...THIS DOES NOT
SEEM REASONABLE BASED ON THE LOW LEVEL THICKNESS AND THE 850 MB
TEMPERATURE DIFFERENCE. WILL LEAVE IT A MIX BUT THIS WILL HAVE TO
BE WATCHED. NONE THE LESS WITH THE SURFACE TEMPERATURE IN THE MID
30S IT WILL BE TOUGH TO ACCUMULATE...MAY BE A LITTLE ON GRASSY
SURFACES. SOME RAIN OR SNOW SHOWERS WILL LINGER MAINLY EAST
THURSDAY MORNING. DRY FRIDAY AND THEN A CHANCE OF RAIN OR SNOW
SHOWERS LATE FRIDAY NIGHT AS ANOTHER FRONT HEADS TOWARD THE AREA.
QPF FOR THIS EVENT FROM TONIGHT THROUGH THURSDAY WILL BE AN INCH OR
LESS OF RAIN. NO FLOODING IS EXPECTED. SOME PONDING OF WATER ON
ROADS MAY OCCUR AS THE GROUND IS SATURATED.
THE WIND IS THE BIGGEST CONCERN FOR LATE WEDNESDAY INTO THURSDAY
MORNING. STILL SOME ISSUES WHETHER THE WINDS WILL JUST BE IN THE
ADVISORY CATEGORY OR WILL NEED A HIGH WIND WARNING. THE COLD
ADVECTION SEEMS STRONG AT FIRST AND WITH 925 MB WINDS IN THE 40 TO
50 KNOT RANGE CONCERNED. SOME OF THE STRONGEST WINDS WILL BE ALONG
THE LAKESHORE. STILL SOME QUESTION WHETHER THE WATCH SHOULD BE
FOR THE WHOLE FORECAST AREA OR JUST ALONG THE LAKESHORE. AT THIS
TIME WILL NOT ISSUE THE WATCH AS SOME OF THE STRONG WINDS COULD
OCCUR WITH THUNDER AND SEVERE THUNDERSTORM WARNINGS WILL BE
NEEDED. ADDED CHANCE OF THUNDERSTORMS FOR WEDNESDAY AFTERNOON.
TEMPERATURES ARE TOUGH ON WEDNESDAY. WENT TOWARD THE WARMER GUIDANCE.
THESE HIGHS WILL BE A FEW DEGREES BELOW THE RECORD HIGHS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
UPPER LEVEL TROUGHS THREATEN TO STRIKE THE AREA BY THE END OF THE
WEEK AND THEN FLATTEN OUT AS THEY REACH THE FORECAST AREA. FLOW
TRIES TO BECOME MORE ZONAL BY SUNDAY EVENING ACROSS MUCH OF THE
COUNTRY. BUT THEN AS WE APPROACH THE END OF THE YEAR...YET ANOTHER
TROUGH SWINGS THROUGH THE FORECAST AREA. THIS SYSTEM WILL BE RATHER
QUICK TO MOVE THROUGH THE REGION AND WILL BRING WITH IT THE
POTENTIAL FOR A GLANCING BLOW OF COLDER AIR TO THE REGION.
IN THE MEAN TIME...STILL EXPECTING TEMPERATURES TO REMAIN ABOVE
NORMAL THROUGH THE FORECAST PERIOD. LOW PRESSURE IS PROGGED TO MOVE
NORTHEAST INTO THE CENTRAL GREAT LAKES BY SATURDAY MORNING. THIS
STORM SYSTEM WILL FORCE A COLD FRONT TO MOVE EAST ACROSS THE AREA
SATURDAY. A REINFORCING SHOT OF COLD AIR WILL PUSH SOUTHEAST INTO
THE AREA SATURDAY NIGHT INTO SUNDAY MORNING. HOWEVER...THE SECONDARY
FRONT IS EXPECTED TO STALL OVER EXTREME NORTHERN OHIO AND NORTHWEST
PENNSYLVANIA. HIGH PRESSURE WILL MOVE EAST INTO THE SOUTHERN GREAT
LAKES BY SUNDAY AFTERNOON AND THEN LIFT NORTHEAST TO QUEBEC BY
SUNDAY NIGHT. TRUE ARCTIC AIR MASS WILL NOT REALLY PUSH INTO THE
AREA DURING THIS FORECAST PERIOD. NEXT BEST SHOT OF COLD AIR WILL
NOT ARRIVE UNTIL WEDNESDAY IN TIME FOR THE NEW YEAR. EVEN THIS SHOT
OF COLD AIR APPEARS TO BE A GLANCING BLOW AND QUICKLY RETREATS TO
THE EAST.
THE COLD FRONT EXPECTED TO MOVE EAST INTO THE REGION ON SATURDAY
WILL HAVE LIMITED MOISTURE AT BEST AND MAY LIMIT THE AMOUNT OF
PRECIPITATION WE SEE WITH THE FEATURE.
DRIER AIR QUICKLY PUSHES INTO THE REGION FROM THE NORTHWEST IN
ADVANCE OF THE HIGH PRESSURE AND THIS SHOULD BRING A RETURN BACK TO
FAIR WEATHER TO THE REGION SUNDAY NIGHT INTO MONDAY. SOME LAKE
EFFECT SNOW SHOWER ACTIVITY IS POSSIBLE SATURDAY NIGHT INTO SUNDAY
IN NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA IN THE COLD AIR
ADVECTION.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
LOW PRESSURE LOCATED WEST OF CHICAGO WILL LIFT A WARM FRONT NORTH
ACROSS THE AREA TODAY WHICH IS CONTRIBUTING TO LOW CEILINGS AND
LOCALIZED RESTRICTIONS TO VISIBILITY. DOWNSLOPING WINDS AT CLE/ERI
WILL LIKELY KEEP CEILINGS IN THE MVFR RANGE WHILE OTHER SITES ARE
MOSTLY IFR. CAK/YNG MAY SEE CEILINGS LIFT FOR A FEW HOURS BEFORE
LOWERING AGAIN TONIGHT.
SCATTERED SHOWERS WILL INCREASE FROM THE SOUTH AFTER 22Z AND FILL
IN TONIGHT AS A STRONGER LOW PRESSURE SYSTEM TRACKS UP FROM THE
SOUTH. EXPECTING POOR AVIATION CONDITIONS WITH CEILINGS BELOW 500
FEET FOR MOST SITES EXCEPT ERI BY 09Z. EASTERN AREA MAY SEE A BREAK
IN THE RAIN DURING THE DAY ON WEDNESDAY. LEANED TOWARDS THE SLOWER
TRACK/TIMING OF THE NAM WHICH DOES NOT BRING THE REAL STRONG WINDS
ASSOCIATED WITH THE COLD FRONT INTO THE TAFS UNTIL CLOSER TO 00Z
SO DID NOT INCLUDE IN THE TERMINALS WITH THIS PACKAGE.
.OUTLOOK...STRONG SOUTHWEST WINDS GUSTING TO 40 KNOTS POSSIBLE
02-10Z THURS. NON VFR POSSIBLE THROUGH THURSDAY THEN AGAIN
SATURDAY AND SUNDAY.
&&
.MARINE...
GALE WATCHES HAVE ALREADY BEEN POSTED FOR WEDNESDAY AFTERNOON INTO
THURSDAY MORNING AS WINDS ON THE LAKE ARE EXPECTED TO INCREASE TO 35
TO 40 KNOTS. THIS IS IN RESPONSE TO STORM SYSTEM EXPECTED TO MOVE
NORTHEAST INTO THE FORECAST AREA AND AFFECT THE LAKE. GRADIENT WILL
BE QUITE STRONG AND THIS WILL CAUSE THE STRONGER WINDS ON THE LAKE.
AT THIS TIME...DO NOT EXPECT TO SEE STORM FORCE WINDS ON THE LAKE.
WINDS WILL GRADUALLY DIMINISH THURSDAY AFTERNOON AND THURSDAY NIGHT.
SOUTHERLY FLOW QUICKLY RETURNS BY THURSDAY NIGHT INTO FRIDAY AS HIGH
PRESSURE SCOOTS BY TO THE SOUTH OF THE AREA. THIS SHOULD SET UP SOME
WARM AIR ADVECTION OVER THE LAKE REDUCING THREAT OF HIGH WAVES BY
FRIDAY. NEXT STORM SYSTEM APPROACHES FROM THE WEST FORCING A COLD
FRONT ACROSS THE LAKE ON SATURDAY. WINDS AHEAD OF THE COLD FRONT
ARE EXPECTED TO INCREASE ON SATURDAY AND WILL LIKELY NEED SMALL
CRAFT ADVISORIES BY THEN.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY AFTERNOON
FOR LEZ061-142>149-162>169.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA/MULLEN
SHORT TERM...KIELTYKA
LONG TERM...LOMBARDY
AVIATION...KEC
MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1147 AM CST TUE DEC 23 2014
.UPDATE...
GIVEN TRENDS...HAVE INCREASE WIND SPEEDS THIS AFTERNOON AND
HOISTED A WIND ADVISORY. THERE IS A BIT OF A CLEARING MOVING
THROUGH THE CWFA WHICH IS HELPING TO MIX WINDS DOWNWARD YIELDING
SPEEDS IN THE LOWER 30S JUST TO OUR NORTH. THE HRX AND REE WEST TEXAS
MESONET SODARS HAVE ALSO INDICATED 50KT SPEEDS NOT FAR OFF THE DECK.
MORE CLOUDINESS CONTINUES TO MOVE SOUTH THROUGH THE PANHANDLE AND
SHOULD HELP SUPPRESS SPEEDS A BIT MORE LATER THIS AFTERNOON BEFORE
BOUNDARY LAYER DECOUPLING ALLOWS SIGNIFICANTLY LOWER SPEEDS THIS
EVENING AND OVERNIGHT.
&&
.AVIATION...
MOSTLY VFR CONDITIONS ARE EXPECTED NEXT 24 HOURS WITH SOME
POTENTIAL FOR MVFR CEILINGS MAINLY AFTER 03Z AT ALL THREE
TERMINALS. MAIN CONCERN WILL BE GUSTY NORTHERLY WINDS WITH
SUSTAINED SPEEDS IN THE 25 TO 30 KT RANGE ALONG WITH HIGHER GUSTS.
NOTE THAT INCREASING MID LEVEL MOISTURE MAY INCREASE ICING
POTENTIAL THIS EVENING.
&&
.PREV DISCUSSION... /ISSUED 525 AM CST TUE DEC 23 2014/
AVIATION...
VFR CONDITIONS IN PLACE AT ALL THREE TAF SITES BUT EXPECT KLBB AND
KPVW TO BOUNCE AROUND BETWEEN VFR AND MVFR. LIGHT PRECIPITATION
MAY IMPACT KPVW AND KLBB OVER THE NEXT 3 HOURS BUT COVERAGE WILL
BE SO SPOTTY AND AMOUNTS SO LIGHT THAT GOING WITH ANY MENTION
WOULD NOT BE WARRANTED. WILL WATCH THROUGH THE MORNING AND AMEND
IF NECESSARY. WIND SPEED WILL CONTINUE TO RAMP UP THROUGH THE DAY
POSSIBLY REACHING THE 25 TO 30 KT SUSTAINED OUT OF THE NORTH WITH
HIGHER GUSTS. ADDITIONAL SHOWERS THIS AFTERNOON MAY IMPACT KCDS
BUT REMAIN EAST OF KLBB AND KPVW. THESE SHOULD BE HIGH ENOUGH TO
KEEP VFR CONDITIONS IN PLACE. AFTER SUNSET...WIND SPEEDS WILL
DECREASE AND VFR CONDITIONS WILL PREVAIL.
JORDAN
PREV DISCUSSION... /ISSUED 432 AM CST TUE DEC 23 2014/
SHORT TERM...
THE HEAVIEST BANDS OF PRECIPITATION HAVE MOVED SOUTH OF THE
AREA...FASTER THAN PRETTY MUCH EVERY OPERATIONAL MODEL RUN HAD IN
THE 12Z RUNS YESTERDAY AND THE 00Z RUNS TODAY. BEST MODELS HAVE
BEEN THE HRRR AND TTU-WRF WHICH BOTH SEEM TO BE FAIRLY CLOSE IN
THEIR FORECASTS COMPARED TO OBSERVED RADAR DATA. WV SATELLITE LOOP
SHOWS THE TROF AXIS IS ALMOST OVERHEAD AS IT DRIFTS OFF TO THE
EAST. THERE ALSO APPEARS TO BE TIGHTENING OF A CIRCULATION EAST OF
THE FOUR CORNERS AREA ALONG THE CO/NM BORDER THAT IS LIKELY HELPING
TO GENERATE SOME OF THE ADDITIONAL RETURNS ON RADAR ACROSS EASTERN
NEW MEXICO.
ANY PRECIPITATION ONGOING ACROSS THE AREA THIS MORNING WILL LIKELY
REMAIN A MIX OF RAIN/SNOW AS SURFACE TEMPERATURES ARE JUST NOW
STARTING TO FLIRT WITH FREEZING. THE TREND HAS BEEN FOR A GRADUAL
DECREASE IN AERIAL COVERAGE IN THE RETURNS BUT THERE COULD STILL BE
SOME MIXED PRECIP REACHING THE GROUND BY SUNRISE...MAINLY ACROSS THE
WESTERN AND SOUTHERN SOUTH PLAINS. THIS ACTIVITY SHOULD CONTINUE TO
DECREASE THROUGH THE MORNING RESULTING IN A BRIEF LULL LATE MORNING
THROUGH EARLY AFTERNOON. STILL IS SOME CONCERN ON HOW STRONG WIND
SPEEDS WILL BECOME THIS AFTERNOON AS THE GFS STILL WANTS TO RAMP
WINDS UP TO 25-35 MPH SUSTAINED ACROSS MOST OF THE CAPROCK. ALL
OTHER MODELS ABOUT 10 MPH LOWER SO WE OPTED TO KEEP WIND SPEEDS
BELOW WIND ADVISORY CRITERIA FOR OUR AREA THIS AFTERNOON. MODELS
CONTINUE TO HINT AT THE POSSIBILITY OF SOME WRAP AROUND
PRECIPITATION THIS AFTERNOON AS ANOTHER VORTMAX STRENGTHENS ON THE
BACK SIDE OF THE TROF AXIS. HIGHER RESOLUTION TTU-WRF AND HRRR ARE
HINTING THAT THESE WILL BE FAIRLY ISOLATED SHOWERS...NOT ANYTHING
THAT WILL BE ABLE TO PROVIDE WIDESPREAD PRECIPITATION AMOUNTS.
FORECAST SOUNDINGS SHOW THAT LAPSE RATES INCREASE A BIT AS THE
SECOND VORT MAX ROTATES AROUND THE BACKSIDE OF THE TROF AND THERE IS
JUST ENOUGH MOISTURE ALOFT TO GENERATE SOME PRECIPITATION. COVERAGE
IS LIMITED TO THE ROLLING PLAINS WHICH WILL BE CLOSER TO THE TROF
AXIS AND WHERE SLIGHTLY GREATER LAPSE RATES WILL BE IN PLACE ALOFT.
INCREASED POPS ACROSS THE ROLLING PLAINS TO ADD SLIGHT CHANCE OF
SHOWERS AS A RESULT. TEMPERATURES WILL CLIMB TO NEAR 50 ACROSS HERE
SO PROFILE WILL BE TOO WARM FOR ANY KIND OF A MIX OF PRECIPITATION.
CAPROCK WILL BE COOLER MAINLY DUE TO THE PRECIPITATION THAT HAS
FALLEN...CLOUD COVER...AND THE BRISK NORTH WIND.
ANY PRECIPITATION WILL COME TO AN END AFTER SUNSET AS THE TROF AXIS
SLIDES OFF TO THE EAST AND AS LAPSE RATES START TO DECREASE.
TEMPERATURES TONIGHT WILL BE PRETTY CHILLY BUT NOT AS COLD AS IT
COULD BE AS WIND SPEEDS WILL REMAIN UP DUE TO THE PRESSURE GRADIENT
REMAINING SOMEWHAT TIGHT. STILL WILL SEE READINGS ACROSS THE
NORTHWESTERN SOUTH PLAINS MAKE IT INTO THE UPPER TEENS WITH THE
ROLLING PLAINS HOVERING AROUND FREEZING.
JORDAN
LONG TERM...
THE FINAL DAYS OF 2014 LOOK TO CLOSE OUT ON A CHILLY NOTE AS A
LARGE SCALE PATTERN CHANGE UNFOLDS AND DIRECTS ARCTIC AIR INTO
MUCH OF MIDDLE CONUS INCLUDING WEST TX. THIS TRANSITION WILL
ALREADY BE IN FULL SWING FRIDAY INTO THE WEEKEND...BUT UNTIL THEN
A WARMING TREND IN STORE UNDERNEATH RISING HEIGHTS BEHIND TODAY/S
UPPER TROUGH. CHRISTMAS DAY IS STILL SHAPING UP QUITE MILD AS LEE
TROUGHING DEEPENS TO OUR WEST AND SUBJECTS MUCH OF THE CWA TO AN
ENHANCED BAND OF SWLY GRADIENT WINDS. EDGED MAX TEMPS UP CLOSER TO
THE ECMWF MOS AS MAV AND MET APPEAR SUSPICIOUSLY COOL FOR THIS
DEEP SWLY FLOW REGIME.
ECM AND GFS ARE IN GOOD ACCORD WITH A STRONG COLD FROPA BY FRI AS
A PIECE OF A TROUGH IN THE FOUR CORNERS LIFTS NORTHEAST. WHERE
THESE MODELS DIFFER IS HOW MUCH ENERGY LINGERS BACK IN THE MAIN
TROUGH AXIS TO OUR WEST FOR FRI NITE INTO THE WEEKEND. THE DEEPER
ECM ADVECTS SUBTROPICAL MOISTURE NEWD ATOP OUR COOL DOME AND AS
SUCH IS EAGER TO GENERATE BOTH LIFT AND QPF ALONG THE ELEVATED
FRONTAL SURFACE. THE GFS IS DRIER AND ABOUT 40 METERS HIGHER WITH
500MB HEIGHTS COMPARED TO ITS FIERCEST COMPETITOR...BUT STILL
GARNERS LIGHT QPF ON SAT WITH ITS DAMPENED TROUGH. EARLIER
SUPERBLEND POPS WERE MASSAGED A BIT TO BETTER WEIGHT THE LATEST
00Z GUIDANCE...BUT A VERY LIGHT RAIN/SNOW EVENT REMAINS IN THE
CARDS FOR FRI NITE-SAT.
BY LATE WEEKEND AND MONDAY...THE STAGE LOOKS PRIMED FOR AN ARCTIC
DUMP AS DEEP NLY FLOW ENSUES FROM THE CANADIAN ROCKIES SOUTH TO
THE CENTRAL HIGH PLAINS. MODELS AND ENSEMBLES ARE NOT DEVIATING MUCH
WITH THIS PATTERN CHANGE...SO CONFIDENCE IS MOUNTING THAT OUR MILD
DECEMBER MAY END ON A CHILLY NOTE. IF THE ARCTIC AIR IS AS STRONG
AS CURRENTLY PROGGED...WE WOULD NOT BE SURPRISED TO AT LEAST SEE
FREEZING DRIZZLE AT SOME POINT EARLY NEXT WEEK AS THESE ARCTIC
AIRMASSES CAN BE NOTORIOUS FOR SUSTAINING LOW CLOUDS ALONG THE
SHARP FRONTAL INVERSION. TEMPS WERE EDGED DOWN IN LINE WITH
CONSALL...BUT IT/S TOO SOON TO JUMP ON ANY POPS EVEN WITH A
DEEPENING TROUGH PROGGED TO OUR WEST BY MON/TUE.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 38 18 46 24 63 / 20 0 0 0 0
TULIA 40 22 48 27 63 / 10 0 0 0 0
PLAINVIEW 41 25 48 28 63 / 10 0 0 0 0
LEVELLAND 41 24 47 27 64 / 20 0 0 0 0
LUBBOCK 42 25 47 29 64 / 10 0 0 0 0
DENVER CITY 42 24 48 28 65 / 20 0 0 0 0
BROWNFIELD 43 25 48 28 64 / 20 0 0 0 0
CHILDRESS 47 31 50 31 67 / 20 10 0 0 0
SPUR 47 28 50 30 65 / 10 0 0 0 0
ASPERMONT 49 30 51 31 66 / 20 10 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: TXZ021>038.
&&
$$
26/99/26