Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/28/13
AREA FORECAST DISCUSSION
NWS NEW YORK NY
454 PM EST TUE NOV 26 2013
.SYNOPSIS...
LOW PRESSURE OVER THE SOUTHEAST STATES LATE THIS AFTERNOON WILL
INTENSIFY AND MOVE UP THE COAST TONIGHT...PASSING OVER THE AREA ON
WEDNESDAY AND THEN HEADING INTO EASTERN CANADA WEDNESDAY NIGHT.
HIGH PRESSURE WILL THEN BUILDS IN FROM THURSDAY THROUGH
SATURDAY...AND MOVE OFF THE NEW ENGLAND COAST ON SUNDAY. A COASTAL
FRONT WILL DEVELOP ON SUNDAY AND REMAIN INTO MONDAY. LOW PRESSURE
WILL DEVELOP ON THE FRONT AND MOVE ALONG THE COAST ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
IMPENDING STORM WILL BRING A VARIETY OF WEATHER HAZARDS BEGINNING
TONIGHT. FIRST...SFC TEMPS HAVE BARELY BUDGED THIS AFTERNOON IN
MOST OF ORANGE COUNTY WHILE TEMPS CONTINUE TO WARM ALOFT...WITH
PRECIP CHANGING TO LIGHT FREEZING RAIN. HAVE THEREFORE CONTINUED
THE WINTER WX ADVISORY THERE INTO THIS EVENING. TEMPS SHOULD
EVENTUALLY RISE LATER THIS EVENING AS LOW LEVEL WARM ADVECTION
CONTINUES...CHANGING PRECIP THERE TO ALL RAIN BY LATE EVENING.
ELSEWHERE...RAIN WILL CONTINUE TONIGHT AND PICK UP IN INTENSITY
FROM LATE EVENING ON AS PRIMARY LOW PRESSURE WEAKENS ALONG A LOW
LEVEL BAROCLINIC ZONE ALONG THE COASTAL PLAIN...AND GIVES WAY TO A
SECONDARY LOW OVER THE MID ATLANTIC FORMING UNDER THE STRENGTHENING
RIGHT ENTRANCE REGION OF A DIFLUENT UPPER JET STREAK APPROACHING
FROM THE WEST AS A NORTHERN/SOUTHERN STREAMS PHASE ALOFT. A S-SE
LOW LEVEL JET WILL INTENSIFY EAST OF THE LOW OVERNIGHT...
TRANSPORTING ATLANTIC/GULF MOISTURE INTO THE REGION AND PROVIDING
AMPLE LOW LEVEL CONVERGENCE/LIFT FOR HEAVY RAIN. OROGRAPHIC LIFT
WILL ALSO COME INTO PLAY NORTH/WEST OF NYC GIVEN THE LOW LEVEL
SE FLOW TO START. GIVEN THESE FACTORS THE POTENTIAL FOR
AREAL/URBAN FLOODING AND FLOODING OF SMALL STREAMS NOW LOOKS
GREAT ENOUGH TO WARRANT A FLOOD WATCH.
THE LLJ ALSO LOOKS STRONG ENOUGH TO SUPPORT STRONG SE-S WINDS
ALONG THE COAST...SO THE WIND ADVY CONTINUES. VERY STRONG NAM LLJ
WITH 85-95 KT AT H8 MAY LOOK LIKE AN OUTLIER COMPARED TO
WEAKER/FARTHER EAST GFS/ECMWF...BUT LATEST RUNS OF THE RAP DO LEND
IT SUPPORT SO AM NOT WILLING TO DISCOUNT IT. SFC-H8 INVERSION
SHOULD PREVENT THE STRONGEST OF THESE WINDS FROM MIXING DOWN.
HOWEVER HAVE A NAGGING CONCERN THAT DUCTED GRAVITY WAVES COULD
AID IN DOWNWARD MOMENTUM TRANSPORT TOWARD MORNING PER AKQ
RESEARCH...AS WEAK INSTABILITY MOVES IN ALOFT JUST NORTH OF AN
APPROACHING WARM FRONT...AND AS THE UPPER JET STREAK APPROACHES
THE DOWNSTREAM INFLECTION POINT BETWEEN THE UPPER TROUGH TO THE
WEST AND OFFSHORE RIDGING...SO POTENTIAL FOR 60+ MPH WIND GUSTS
ACROSS LONG ISLAND AND COASTAL SE CT WILL HAVE TO BE WATCHED. MOST
LIKELY SCENARIO WILL BE FOR SUSTAINED WINDS 25-35 MPH WITH GUSTS
45-50 MPH...MAINLY IN/NEAR NYC AND ALONG THE COAST BEGINNING LATE
TONIGHT.
THERE COULD BE A FEW RUMBLES OF THUNDER LATE AS ELEVATED
INSTABILITY MOVES OVER THE AREA.
TEMPS WILL BE ON THE RISE TONIGHT...REACHING THE MID AND UPPER 50S
BY MORNING.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
THE LOW WILL BE MOVING ACROSS THE REGION WED MORNING INTO EARLY
AFTERNOON...THEN RE-CONSOLIDATING TO THE NORTH IN THE AFTERNOON.
HEAVY RAIN...STRONG SOUTHERLY WINDS AND ISOLD RUMBLES OF THUNDER
WILL STILL BE ONGOING INITIALLY...THEN SHOULD SHIFT TO THE EAST
ACROSS ERN LONG ISLAND/CT DURING LATE MORNING AND LIFT UP INTO NEW
ENGLAND BY AFTERNOON AS THIS TAKES PLACE. ENDED WIND ADVY EARLIER
THAN ORIGINALLY FCST SINCE THE LOW TRACK SHOULD BE SLIGHTLY
FARTHER EAST...WITH THE LLJ ALSO PASSING TO THE EAST SOONER.
RAIN SHOULD LESSEN IN INTENSITY AS WELL AS AS THE LLJ PASSES TO
THE EAST.
AS THE LOW MOVES OVER THE AREA...THERE SHOULD BE A RELATIVE LULL
IN WINDS FROM LATE MORNING INTO EARLY AFTERNOON...THEN STRONG NW
WINDS WILL REDEVELOP BY EVENING AS THE LOW CONTINUES TO INTENSIFY
AND SHOULD CONTINUE INTO THE NIGHT...SUSTAINED AT 20-30 MPH WITH
GUSTS UP TO 40 MPH...POSSIBLY STRONGER IN NYC METRO AND LONG
ISLAND WHERE ANOTHER WIND ADVY MAY BE NEEDED. STILL EXPECT SCT
SHOWERS IN THE EVENING AS THE UPPER TROUGH MOVES ACROSS...AND LOW
LEVEL CAA SHOULD CHANGE ANY PRECIP OVER TO SNOW FROM NYC
NORTH/WEST. SOME INTERIOR AREAS COULD SEE A LIGHT COATING OF
ACCUMULATION OF SNOW BEFORE ALL PRECIP ENDS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
VIGOROUS SHORTWAVE IS ROTATING EAST OF THE REGION EARLY THURSDAY
MORNING AS BROAD UPPER TROUGH REMAINS ACROSS THE NORTHEAST. ANOTHER
SHORTWAVE ROTATES THROUGH THE TROUGH LATE THURSDAY INTO THURSDAY
NIGHT. MEANWHILE AT THE SURFACE LOW PRESSURE WILL BE NORTH AND EAST
OF THE AREA AND CONTINUING TO MOVE NORTH DURING THE DAY INTO
THURSDAY NIGHT AS HIGH PRESSURE BUILDS TO THE WEST. INCREASING
SUBSIDENCE BEHIND THE LOW WILL KEEP AREA PRECIPITATION FREE
THURSDAY...ALTHOUGH CLOUDS WILL LINGER EARLY IN THE DAY. UPPER FLOW
BECOMES MORE ZONAL FRIDAY AND INTO THE WEEKEND AS SURFACE HIGH
PRESSURE BUILDS OVER THE REGION. WARM ADVECTION SETS UP LATE
SATURDAY NIGHT AND INTO SUNDAY AS HIGH PRESSURE MOVES EAST AND NEXT
SHORTWAVE APPROACHES FROM THE GREAT LAKES. LIFT IS RATHER WEAK AT
THIS TIME AND MOISTURE LIMITED HOWEVER...THERE IS A VERY LOW
PROBABILITY OF LIGHT PRECIPITATION LATE SATURDAY NIGHT. SUNDAY WILL
BE A BETTER CHANCE AS ADVECTION CONTINUES AND GULF MOISTURE MOVES
INTO THE AREA. AS THE HIGH RETREATS TO THE NORTHEAST SATURDAY NIGHT
INTO SUNDAY...COLD AIR DAMNING IS POSSIBLE AND MIXED PRECIPITATION
WILL BE POSSIBLE INLAND AS COASTAL AREAS WARM IN THE SOUTHERLY FLOW.
A COASTAL FRONT DEVELOPS SUNDAY INTO MONDAY AS A WEAK SOUTHERN
STREAM SHORTWAVE MOVES OUT OF THE SOUTHWEST AND INTO THE GULF COAST
REGION. THIS WAVE WILL DEVELOP A LOW ALONG THE COASTAL FRONT MONDAY
INTO TUESDAY. STILL SOME UNCERTAINTY WITH THE TRACK OF LOW WITH THE
ECMWF CLOSER TO THE COAST AND THE GFS MOVING THE LOW FARTHER OFF THE
SOUTHEASTERN COAST AND KEEPING THE REGION ON THE NORTHWESTERN EDGE
OF THE PRECIPITATION TUESDAY.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
HIGH IMPACT AVIATION WEATHER EVENT FOR TONIGHT AND WEDNESDAY.
CONDITIONS DIMINISHING QUICKLY THIS EVENING.
THIS EVENING...WINDS LIGHT SE 5-12 KT WITH LOWERING CEILINGS AND
LIGHT RAIN MOVING ACROSS ENTIRE TERMINAL AREA.
AFTER 00Z...CIGS AND VSBYS LOWER TO IFR OR LESS AND RAIN WILL
BECOME MODERATE TO HEAVY AT TIMES. WINDS AND GUSTS INCREASE AFTER
05Z ESPECIALLY ACROSS THE NYC TERMINALS AND POINTS EAST. BY
08-09Z...GUSTS WILL REACH 35-40 KT. CAN NOT RULE OUT SOME ISOLATED
GUSTS TO 45 KT IN CONVECTIVE ELEMENTS. IN ADDITION...A STRONG LOW LEVEL
JET WILL RESULT IN WIND SHEAR SO HAVE INCLUDED IN THE
TAFS AFTER 08Z. SPEEDS AT 2000 FT COULD APPROACH 70 KT...MAINLY
EASTERN TERMINALS.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: MODERATE TO HIGH CONFIDENCE FORECAST. AMENDMENTS
MAY BE NEEDED TO FINE TUNE ANY WIND SHIFTS AND TIMING OF LOWER
CIGS AND PRECIPITATION THIS EVENING.
KLGA FCSTER COMMENTS: MODERATE TO HIGH CONFIDENCE FORECAST. AMENDMENTS
MAY BE NEEDED TO FINE TUNE ANY WIND SHIFTS AND TIMING OF LOWER
CIGS AND PRECIPITATION THIS EVENING.
KEWR FCSTER COMMENTS: MODERATE TO HIGH CONFIDENCE FORECAST. AMENDMENTS
MAY BE NEEDED TO FINE TUNE ANY WIND SHIFTS AND TIMING OF LOWER
CIGS AND PRECIPITATION THIS EVENING.
KTEB FCSTER COMMENTS: MODERATE TO HIGH CONFIDENCE FORECAST. AMENDMENTS
MAY BE NEEDED TO FINE TUNE ANY WIND SHIFTS AND TIMING OF LOWER
CIGS AND PRECIPITATION THIS EVENING.
KHPN FCSTER COMMENTS: MODERATE TO HIGH CONFIDENCE FORECAST. AMENDMENTS
MAY BE NEEDED TO FINE TUNE ANY WIND SHIFTS AND TIMING OF LOWER
CIGS AND PRECIPITATION THIS EVENING.
KISP FCSTER COMMENTS: MODERATE TO HIGH CONFIDENCE FORECAST. AMENDMENTS
MAY BE NEEDED TO FINE TUNE ANY WIND SHIFTS AND TIMING OF LOWER
CIGS AND PRECIPITATION THIS EVENING.
.OUTLOOK FOR 18Z WEDNESDAY THROUGH MONDAY...
.WED...LIFR...IMPROVING WEST TO EAST DURING THE AFTERNOON. +RA
THROUGH MID MORNING. STRONG S/SE SURFACE WIND...HIGHEST NY METRO
AND EAST...25-35G40-45KT EARLY AM. WIND LIGHTENS MIDDAY AS LOW
PASSES JUST WEST OF NY METRO. WIND VEERS SW/W LATE AND INCREASES
AGAIN. LLWS AND COMPRESSION LIKELY WITH 70+ KT AT FL020 IN THE
EARLY AM.
.WED NGT. MVFR...BECOMING VFR. CHC -SHSNRA. W/NW WINDS 20-25G35KT.
.THU...VFR. NW WINDS 20-25G30-35KT EARLY SLOWLY DIMINISHING TO G20KT
BY EVENING.
.THU NGT-SAT...VFR.
.SUN AND MON...MVFR CIG. -DZ / -RA. SE SFC FLOW 10-15 KT.
&&
.MARINE...
THE PRESSURE GRADIENT WILL QUICKLY TIGHTEN TONIGHT AHEAD OF AN
ADVANCING STORM SYSTEM TRACKING FROM THE SOUTHEASTERN TO COASTAL
MID ATLANTIC STATES TONIGHT...WITH WIND GUSTS TO GALE LEVELS
DEVELOPING AFTER MIDNIGHT. A FEW GUSTS TO STORM FORCE MAY BE
POSSIBLE TOWARD MORNING...MAINLY ON THE ERN OCEAN WATERS...BUT
THESE SHOULD BE BRIEF AT BEST AND SO DID NOT UPGRADE ANY AREAS TO
A STORM WARNING. WILL USE SPECIAL MARINE WARNINGS TO ADDRESS ANY
WIND GUSTS OF 48 KT OR HIGHER IN ISOLATED STRONGER CONVECTION.
SEAS COULD BUILD AS HIGH AS 16 FT ON THE ERN OCEAN WATERS WITH THE
STRONGEST SOUTHERLY WINDS.
THERE COULD BE A LULL IN WINDS FROM LATE WED MORNING INTO THE
AFTERNOON...BUT THEN NW GALES ARE EXPECTED WED NIGHT INTO
THU MORNING...WITH SEAS UP TO 15 FT EXPECTED WED NIGHT ON THE
OCEAN AND AS HIGH AS 7 FT ON LONG ISLAND SOUND AS THE SURFACE LOW
CONTINUES TO TRACK TO THE NORTH THROUGH CANADA AND HIGH PRESSURE
BUILDS TO THE WEST. THE WIND WILL BE DIMINISHING THROUGH THE DAY
THURSDAY...SUBSIDING BELOW GALE FORCE DURING THE AFTERNOON...AND
THEN QUICKLY FALLING BELOW 25 KT DURING THURSDAY EVENING.
VERY ROUGH SEAS ON THE OCEAN WATERS SUBSIDE DURING THURSDAY IN THE
WEST TO NORTHWEST FLOW. BY LATE THURSDAY NIGHT SEAS ARE EXPECTED TO
FALL BELOW 5 FT AS THE WESTERLY FLOW DIMINISHES.
WIND AND SEAS REMAIN BELOW ADVISORY LEVELS FRIDAY INTO SUNDAY.
DEPENDING ON THE STRENGTH OF THE WIND AROUND A DEPARTING HIGH AND A
DEVELOPING TROUGH ALONG THE COAST...SEAS ON THE OCEAN WATERS MAY
BUILD BACK UP TO SMALL CRAFT LEVELS LATE SUNDAY INTO SUNDAY
NIGHT.
&&
.HYDROLOGY...
WIDESPREAD RAINFALL TOTALS FORECAST RANGE BETWEEN 2 AND 3 INCHES
WITH LOCAL AMOUNTS UP TO 4 INCHES. DUE RECENT PROLONGED DRY
CONDITIONS...MAIN STEM RIVER FLOODING IS NOT EXPECTED.
HOWEVER...THERE IS ENOUGH CHANCE OF URBAN/AREAL/SMALL STREAM
FLOODING...ESPECIALLY WHERE STORM DRAINS ARE CLOGGED BY LEAVES
AND ESSENTIALLY WHERE THERE IS MORE RUNOFF....TO WARRANT A FLOOD
WATCH FROM LATE TONIGHT INTO WED AFTERNOON.
LIGHT PRECIPITATION IS POSSIBLE SUNDAY INTO TUESDAY...WITH A TOTAL
OF UP TO A HALF INCH EXPECTED AT THIS TIME.
&&
.TIDES/COASTAL FLOODING...
A GALE FORCE SE FLOW WILL RAPIDLY DEVELOP AHEAD OF DEEPENING LOW
PRESSURE LATE TONIGHT...BEFORE VEERING TO THE S WEDNESDAY MORNING. A
STORM SURGE OF 2 TO 2 1/2 FT...LOCALLY 3 FT IS EXPECTED. THE PEAK
SURGE COINCIDES BEST WITH THE TIMING OF THE MORNING HIGH TIDE CYCLE
IN WESTERN LONG ISLAND SOUND AND PECONIC BAY. AN ADVISORY HAS BEEN
ISSUED IN THESE LOCATIONS WITH COMBINED THREAT OF STORM TIDE...WAVE
SPLASH-OVER...AND HEAVY RAIN CAUSING WIDESPREAD MINOR IMPACTS.
ELSEWHERE...TIMING OF PEAK SURGE AND HIGH TIDE APPEARS TO BE
OFFSET...WITH ONLY LOCALIZED ISSUES EXPECTED WITH WEDNESDAY MORNING
HIGH TIDE DUE TO STORM TIDE AND HEAVY RAIN. A COASTAL FLOOD
STATEMENT HAS BEEN ISSUED TO ADDRESS THIS THREAT.
FOR THE LATE AFTERNOON/EVENING HIGH TIDE CYCLE...WITH FLOW
EXPECTED TO BEGIN TURN OFFSHORE WOULD EXPECT SURGE VALUES TO BEGIN
TO FALL RAPIDLY FROM AFTERNOON ON. THE ONLY AREA TO MONITOR WOULD BE
THE SOUTH SHORE BACK BAYS WITH HIGH SURF LIMITING TIDAL DRAINAGE.
HIGH SURF AND MINOR EROSION ISSUES ARE EXPECTED LATE TONIGHT THROUGH
LATE WEDNESDAY NIGHT FROM BATTERING SURF OF 7-11 FT. MAIN CONCERN
WILL BE THE VULNERABLE DUNES AND BREACH LOCATIONS POST SANDY. A HIGH
SURF ADVISORY HAS BEEN ISSUED TO ADDRESS THIS THREAT.
&&
.EQUIPMENT...
DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD
EMERGENCY BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS
WEATHER RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL
WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES
TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM.
DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE
INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO
DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE
WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE
INTERFERENCE ISSUE HAS BEEN RESOLVED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...FLOOD WATCH FROM MIDNIGHT EST TONIGHT THROUGH WEDNESDAY
AFTERNOON FOR CTZ005>012.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO 2 PM EST WEDNESDAY FOR
CTZ008-011-012.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST WEDNESDAY FOR
CTZ007-009-010.
COASTAL FLOOD ADVISORY FROM 5 AM TO 8 AM EST WEDNESDAY FOR
CTZ009-010.
NY...FLOOD WATCH FROM MIDNIGHT EST TONIGHT THROUGH WEDNESDAY
AFTERNOON FOR NYZ067>075-078>081-176>179.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO 2 PM EST WEDNESDAY FOR
NYZ078>081-177-179.
COASTAL FLOOD ADVISORY FROM 6 AM TO 9 AM EST WEDNESDAY FOR
NYZ079-081.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST WEDNESDAY FOR
NYZ071>075-176-178.
COASTAL FLOOD ADVISORY FROM 5 AM TO 8 AM EST WEDNESDAY FOR
NYZ071-073.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
NYZ067.
HIGH SURF ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT EST
WEDNESDAY NIGHT FOR NYZ080-081-178-179.
NJ...FLOOD WATCH FROM MIDNIGHT EST TONIGHT THROUGH WEDNESDAY
AFTERNOON FOR NJZ002-004-006-103>108.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST WEDNESDAY FOR
NJZ006.
MARINE...GALE WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST THURSDAY FOR
ANZ330-335-338-340-345-350-353-355.
&&
$$
SYNOPSIS...GOODMAN/MET
NEAR TERM...GOODMAN
SHORT TERM...GOODMAN
LONG TERM...MET
AVIATION...IRD
MARINE...GOODMAN/MET
HYDROLOGY...GOODMAN/MET
TIDES/COASTAL FLOODING...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
415 PM EST TUE NOV 26 2013
.DISCUSSION...
...STRONG THUNDERSTORMS POSSIBLE AFTER SUNSET TONIGHT...
...TURNING MUCH COLDER WEDNESDAY NIGHT INTO THANKSGIVING MORNING...
CURRENTLY/TONIGHT...
CENTRAL FL REMAINS WELL INSIDE THE WARM SECTOR OF THE DVLPG GOMEX
SYSTEM AS AFTN SFC DEWPOINTS REMAIN IN THE U60S/L70S...SFC TEMPS IN
THE U70S/L80S. PREFRONTAL SQUALL LINE HAS DVLPD OVER THE ERN GOMEX
PER LATEST SAT PICS/KTBW RADAR IMAGERY. RUC ANALYSIS SHOWS A POCKET
OF ENHANCED H85-H50 VORTICITY DUE W OF TAMPA CONCURRENT WITH THE
SQUALL LINE...AS WELL AS MODERATE TO STRONG UPR LVL DIVERGENCE
AREAWIDE. H85-H50 STEERING FLOW INDICATES THE CORE ENERGY WILL TRACK
N OF THE I-4 CORRIDOR LATER THIS EVENING...THOUGH LATEST KTBW
TRAJECTORY SHOWS THE BULK OF THE RAINFALL WITH THE CONVECTIVE LINE
LIFTING MORE TOWARD THE BIG BEND.
OUTSIDE OF THE VORT MAX...MID LVL DYNAMIC SUPPORT IS QUITE WEAK WITH
LITTLE IN THE WAY OF DEEP MID LYR VORTICITY OR OMEGA LIFT. MID LVL
LAPSE RATES UNIMPRESSIVE AS WELL...LARGELY BTWN 5.5-6.0C/KM OVER THE
SRN CWA...BLO 5.5C/KM NRN CWA. DESPITE SOME THINNING OF THE MID/UPR
LVL CLOUD DECKS...KMLB/TMCO/KPBI RADARS INDICATE CONVECTION HAS
STRUGGLED TO DVLP WITHIN THIS LCL ENERGY MINIMUM.
DEEP MOISTURE REMAINS IN THE VCNTY OF THE SQUALL LINE WITH H100-H85
AND H85-H50 MEAN RH VALUES AOA 90PCT. MID LVL MOISTURE DIMINISHES A
BIT OVER S FL THOUGH H85-H50 RH STILL BTWN 60-70PCT. MAX 0-3KM
HELICITY VALUES BTWN 300-350 FROM OSCEOLA/BREVARD CO NWD...BUT
EMBEDDED WITHIN A 30-40KT H85-H70 S/SW FLOW THAT WILL CARRY THE BULK
OF IT OUT OF THE CWA BEFORE ANY SIG DESTABILIZATION CAN OCCUR.
ON THE SYNOPTIC SCALE...THE NRN AND SRN STREAM SHORT WAVE TROFS HAVE
MERGED...FORMING A FULL LATITUDE H85-H50 TROF EXTENDING FROM HUDSON
BAY TO THE BAY OF CAMPECHE. THIS TROF WILL DIG STEADILY EWD
OVERNIGHT...PULLING BOTH A STRONG COLD FRONT INTO THE FL PENINSULA.
THE PREFRONTAL CONVECTIVE LINE WILL PUSH INTO CENTRAL FL THRU MID
EVNG WITH AN INITIAL ROUND OF CONVECTION EXPECTED N OF SEBASTIAN
INLET/LAKE KISSIMMEE THRU MIDNIGHT...THEN A SECOND ROUND TO THE S
AFT 3AM. WHILE SVR WX THREAT HAS DIMINISHED...CANNOT RULE OUT HEAVY
RAIN AND LCL STRONG WIND GUSTS AS TSRAS BLOW THROUGH.
BULK OF THE COLD AIR ADVECTION WILL NOT OCCUR UNTIL AFT SUNRISE.
DENSE CLOUD COVER AND STEADY S/SWRLY WINDS OVERNIGHT WILL KEEP MIN
TEMPS 10-15F ABV CLIMO AVG...THE L/M60S N OF I-4...U60S/L70S TO THE
SOUTH.
WED-WED NIGHT...(MODIFIED PREV DISC)
TIMING OF THE SYSTEM SHOULD CARRY THE BULK OF ITS CONVECTION CLEAR
THE CWA BY DAYBREAK AS THE DEEPENING PARENT LOW RACES UP THE ERN
SEABOARD. THE 500MB TROUGH WILL SWING THROUGH BY LATE MORNING...
EFFECTIVELY ENDING ANY PRECIP FOR THE REGION BY MIDDAY. STRONG COLD
AIR ADVECTION WILL COMMENCE QUICKLY BEHIND THE FRONT...BRINGING AN
ARCTIC AIRMASS INTO CENTRAL FL. ITS LIKELY THAT A LAKE WIND ADVISORY
WILL BE NEEDED FOR AT LEAST PART OF THE REGION...MAKING IT THE
FOURTH DAY IN A ROW FOR SOME PLACES.
THE COLD AIR ADVECTION AND LINGERING CLOUD COVER THROUGH LATE
MORNING WILL PREVENT MAX TEMPS FROM RISING MUCH MORE THAN 5F ABOVE
THE MORNING MINS. HIGH IN THE M/U60S ALONG AND N OF I-4...U60S/L70S
TO THE S. MUCH OF THE AREA WILL REACH MAX TEMPS BEFORE NOON THEN
HOLD STEADY OR DROP THRU THE AFTN.
CLEARING SKIES AND STRONG COLD/DRY AIR ADVECTION WILL DROP OVERNIGHT
MINS INTO THE U30S/L40S MOST OF THE CWA W OF I-95. OCEAN INFLUENCE
SHOULD KEEP AREAS E OF I-95 IN THE M/U40S THRU DAYBREAK THU...STILL
A SOLID 20-25F DEG COLDER THAN WED MORNING MINS.
THANKSGIVING DAY-SUNDAY...(PREV DISC)
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT...QUICKLY SPREADING OUT
ACROSS THE DEEP SOUTH AND MID-ATLANTIC BY FRIDAY...BEFORE BEING
REINFORCED BY A SECONDARY HIGH ACROSS NEW ENGLAND INTO THE WEEKEND.
BREEZY NORTH TO NORTH-NORTHEAST FLOW WILL START OFF THE THANKSGIVING
HOLIDAY BEFORE RETURNING TO WHAT HAS BECOME THE DEFAULT PATTERN OF
LATE...BREEZY EAST-NORTHEAST FLOW INTO THE WEEKEND. THE NORTHEAST
WIND SURGE AS THE HIGH BEGINS TO BUILD INTO THE ATLANTIC LATE ON
THURSDAY WILL REINTRODUCE ISOLATED LOW TOPPED ATLANTIC SHOWERS INTO
THE FORECAST THURSDAY NIGHT...AFFECTING COASTAL AREAS FROM FRIDAY
ONWARDS
THANKSGIVING DAY WILL BE COOL AND BLUSTERY WITH HIGHS IN THE MID 60S
IN MOST LOCATIONS. AS THE FLOW REGAINS ITS ONSHORE
COMPONENT...TEMPERATURES WILL MODERATE INTO THE WEEKEND WITH HIGHS
IN THE MID-UPPER 70S AND LOWS IN THE LOW-MID 50S INLAND/MID-UPPER
60S BREVARD/TREASURE COAST BY SATURDAY AND SUNDAY.
&&
.AVIATION...
THRU 27/00Z...S/SE SFC WIND ARND 15KTS WITH G20-25KTS...PREVAILING
VFR VSBYS WITH BRIEF PDS BTWN 3-5SM IN ISOLD SHRAS...VRBL CIGS ALL
SITES PREVAILING BTWN FL080-100 WITH OCNL PDS BTWN FL020-030 IN -RA.
BTWN 27/00Z-27/04Z...WINDS S/SW 10-15KTS WITH 30-35KT SW LLWS PSBL
ALL SITES...SCT NMRS MVFR SHRAS/SCT IFR TSRAS W OF KMLB-KOBE....SCT
MVFR SHRAS/ISOLD IFR TSRAS E OF KMLB-KOBE.
BTWN 27/04Z-27/12Z...SQLN WILL PUSH THRU E CENT FL WITH 35-40KT W/SW
LLWS PSBL ALL SITES. STRONG WIND GUSTS ABOVE 35 KNOTS AND +RA
REDUCING VSBYS/CIGS TO IFR/LIFR CONDS WITH THE PASSAGE OF THE LINE.
&&
.MARINE...
TONIGHT...SCA CONDITIONS TO CONTINUE. LCL DATA BUOY/C-MAN STATIONS
INDICATE SFC/BNDRY LYR WINDS HAVE SHIFTED TO THE S...STILL HOLDING
ARND 20KTS WITH GUSTS ARND 30KTS. LITTLE CHANGE TO SEAS...6-8FT
NEARSHORE AND 8-10FT OFFSHORE WITH DOMINANT PDS AOB 8SEC. STORM
SYSTEM LIFTING INTO THE DEEP SOUTH WILL FORCE SFC/BNDRY LYR WINDS TO
VEER SW OVERNIGHT...INCREASING TO GALE/NEAR GALE FORCE N OF THE CAPE
AFT SUNSET. SCA/GALE WARNING TIMING AND CONFIGURATION LOOK GOOD.
WED-WED NIGHT...(PREV DISC)
DEEPENING LOW PRESSURE SYSTEM WILL MOVE ACROSS N FLORIDA AND UP THE
EASTERN SEABOARD EARLY ON WEDNESDAY WITH A COLD FRONT SWEEPING
THROUGH THE STATE BEFORE MIDDAY. SOUTHWEST-WEST WINDS WILL BE
STRONGEST EARLY IN THE DAY WITH THE LOW AT ITS CLOSEST APPROACH WITH
SPEEDS 25-30KTS NORTH OF THE CAPE AND 20-25KTS SOUTH. WITH FREQUENT
GUSTS TO GALE FORCE EXPECTED...A GALE WARNING WILL BE HOISTED FOR
THE OFFSHORE WATERS NORTH OF SEBASTIAN INLET THROUGH MIDDAY. WINDS
SLOWLY DECREASE THROUGH THE AFTERNOON BECOMING NW 15-20KTS BY THE
EVENING...AND NORTH OVERNIGHT.
SEAS 4-6FT NEARSHORE AND 7-9FT OFFSHORE EARLY...SLOWLY DIMINISHING
TO 4-7FT BY LATE NIGHT. THE PREVAILING OFFSHORE WIND COMPONENT WILL
GENERATE ROUGH AND HAZARDOUS SHORT PERIOD SEAS OVER THE OPEN ATLC
WITHIN A FEW MILES OF SHORE. ROUGH CONDITIONS WILL CONTINUE
OVERNIGHT DUE TO THE OPPOSING DIRECTIONS OF THE NRLY WIND AND THE
SRLY GULF STREAM.
THU-SUN...(PREV DISC)
SURFACE HIGH BUILDING ACROSS THE DEEP SOUTH BEHIND THE FRONT WILL BE
DOMINANT FEATURE THROUGH THE END OF THE WEEK INTO THE WEEKEND. NORTH
WINDS EARLY ON THURS BECOME NORTHEAST BY THE AFTERNOON...BEFORE
VEERING TO THE EAST-NORTHEAST FRI-SUNDAY. SPEEDS GENERALLY
15-20KTS.
INCREASING ONSHORE COMPONENT TO THE FLOW WILL PUSH A STEADY SWELL
INTO THE COAST WITH SEAS 4-6FT ON FRIDAY BUILDING TO 8-9FT OFFSHORE
BY SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 64 67 40 64 / 90 20 0 10
MCO 65 69 40 66 / 90 10 0 0
MLB 68 71 46 68 / 90 30 0 10
VRB 71 73 46 69 / 80 40 0 10
LEE 61 66 36 64 / 90 10 0 0
SFB 65 68 38 65 / 90 10 0 0
ORL 64 68 40 66 / 90 10 0 0
FPR 71 73 46 69 / 80 40 0 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 7 PM EST WEDNESDAY FOR COASTAL
WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE OUT 20
NM-COASTAL WATERS FROM SEBASTIAN INLET TO JUPITER INLET OUT 20
NM-COASTAL WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN
INLET OUT 20 NM-WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20
TO 60 NM OFFSHORE.
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING 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.
SMALL CRAFT ADVISORY FROM 1 PM TO 7 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.
GALE WARNING FROM 10 PM THIS EVENING TO 1 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.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...LASCODY
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
345 PM EST TUE NOV 26 2013
...ISOLATED SEVERE WEATHER POSSIBLE THIS EVENING...
...HAZARDOUS BOATING CONDITIONS THROUGH WEDNESDAY NIGHT...
...HIGH RISK OF RIP CURRENTS ALONG AREA BEACHES THROUGH WEDNESDAY...
...FREEZE WATCH FOR PORTIONS OF THE NATURE COAST WEDNESDAY NIGHT...
.SYNOPSIS...
20Z WATER VAPOR AND H4 RAP ANALYSIS SHOWING AN AMPLIFIED AND
HIGHLY ENERGETIC UPPER LEVEL PATTERN EVOLVING ACROSS THE CONUS. FLOW
RIDGES SHARPLY OVER THE PACIFIC COAST AND INTER-MOUNTAIN WEST BEFORE
DIVING BACK SOUTH INTO DEEP LONGWAVE TROUGHING COVERING THE
REMAINDER OF THE NATION. THIS LONGWAVE TROUGH IS RATHER COMPLEX WITH
BOTH A STRONG NORTHERN STREAM AND SOUTHERN STREAM IMPULSE EMBEDDED
WITHIN. THE NORTHERN STREAM ENERGY IS DROPPING QUICKLY SOUTHEASTWARD
OVER THE UPPER MIDWEST/GREAT LAKES WHILE THE SOUTHERN STREAM IMPULSE
IS CURRENTLY EJECTING EASTWARD ALONG THE NORTHERN GULF COAST.
IT IS THIS POTENT SOUTHERN STREAM IMPULSE WHICH WILL BE THE BIG
PLAYER IN OUR WEATHER OVER THE NEXT 12-24.
CURRENTLY AT THE SURFACE...THE FLORIDA PENINSULA RESIDES WITH A ZONE
OF MODERATE SOUTHEASTERLY TO SOUTHERLY FLOW WITHIN A DEFINED WARM
SECTOR SOUTH AND EAST OF A DEEPENING AREA OF LOW PRESSURE OVER
SOUTHERN AL/GA. FROM THIS LOW...A COLD FRONT TRAILS SOUTHWARD ACROSS
THE CENTRAL GULF OF MEXICO AND WILL MOVE QUICKLY EASTWARD TO CROSS
OUR FORECAST AREA LATER THIS EVENING AND EARLY MORNING HOURS.
REGIONAL RADARS SHOWING WIDESPREAD SHOWERS/THUNDERSTORMS PUSHING
TOWARD THE FLORIDA WEST COAST WITHIN THE ZONE OF IMPRESSIVE SYNOPTIC
ASCENT AHEAD OF THE APPROACHING SOUTHERN STREAM IMPULSE AND SURFACE
FOCUS AHEAD OF THE COLD FRONT. SAW SOME SUNNY BREAKS TODAY WHICH
ALLOWED DECENT SURFACE HEATING AND THE DEVELOPMENT OF SURFACE BASED
INSTABILITY. THIS INSTABILITY IS BEING REALIZED WITH A SCATTERING OF
MAINLY SHOWERS OVER THE LAND AREAS...HOWEVER THE REAL SHOW IN TERMS
OF RAIN/THUNDER IS STILL OVER THE WATER AND SCHEDULED TO REACH THE
COAST BY EARLY EVENING.
&&
.SHORT TERM (EARLY EVENING THROUGH THURSDAY NIGHT)...THE POTENTIALLY
MORE SIGNIFICANT WEATHER IS BEGINNING TO APPROACH FROM THE EASTERN
GULF OF MEXICO. AS WE HEAD INTO THE EVENING HOURS...LARGE SCALE
FORCING FOR ASCENT ASSOCIATED WITH DCVA/HEIGHT FALLS WILL OVERSPREAD
THE AREA. GFS/ECMWF BOTH SHOW A BROAD EXPANSE OF DEEP LAYER QG
FORCING IN PLACE THIS EVENING. THIS IS ONE OF THE MORE POTENT
MID/UPPER LEVEL IMPULSES THAT WE HAVE SEEN MOVE ACROSS THE NE GULF
IN SOME TIME. UPPER LEVEL PV ANOMALY ASSOCIATED WITH THIS IMPULSE IS
VERY IMPRESSIVE WITH THE DYNAMIC TROPOPAUSE FOLDED DOWN ALMOST TO
600MB RESULTING IN AN EQUALLY IMPRESSIVE MID/UPPER LEVEL JET
STRUCTURE. SURFACE LOW REFLECTION AS A RESULT SHOULD CONTINUE TO
DEEPEN THROUGH THE EVENING AHEAD OF THIS FEATURE AS IT CROSSES
INTO SOUTHERN GA. THE COLD FRONT WILL ALSO INTENSIFY/SHARPEN WITH
TIME ADDING ADDITIONAL LOWER LEVEL CONVERGENCE FOCUS. ALL THAT BEING
SAID...RAIN CHANCES ARE CATEGORICAL 80% OR HIGHER FOR JUST ABOUT ALL
COASTAL ZONES THIS EVENING AND INLAND ZONES LATE THIS EVENING INTO
THE EARLY MORNING HOURS. RAIN CHANCES WILL TAPER OFF QUICKLY WITH
THE PASSAGE OF THE COLD FRONT FROM WEST TO EAST DURING THE SECOND
HALF OF THE NIGHT AND HAVE ALL RAIN CHANCES (EVEN FOR OUR FAR
EASTERN ZONES) REMOVED BY SUNRISE TOMORROW MORNING. THE CONVECTIVE
START AND END TIMES AGREE WELL WITH THE ENSEMBLE SUITE OF
LOCAL/NATIONAL HIGH RESOLUTION MODELS AND ALSO THE HOPWRF ENSEMBLES
BEING RUN OVER THE SE CONUS TODAY.
SEVERE THREAT...DESPITE THE EXPECTED WIDESPREAD COVERAGE OF SHOWER
AND STORMS DUE TO THE STRONG SYNOPTIC FORCING...THE OVERALL SEVERE
THREAT SHOULD BE ISOLATED IN NATURE. THE STORM PREDICTION CENTER HAS
OUTLOOKED MUCH OF OUR AREA IN A SLIGHT RISK FOR SEVERE WEATHER AND
AGREE WITH THIS ASSESSMENT. A NEW TORNADO WATCH HAS JUST BEEN ISSUED
TO INCLUDE SARASOTA...MANATEE...PINELLAS...HILLSBOROUGH...POLK...
PASCO...HERNANDO...SUMTER...CITRUS...AND LEVY COUNTIES. DEEP LAYER
0-6KM BULK SHEAR (35-40KTS) AND MLCAPE ARE NOT OVERLY IMPRESSIVE...
BUT CERTAINLY SUFFICIENT FOR ORGANIZED CONVECTION. MID-LEVEL LAPSE
RATES ARE ON THE POOR SIDE FOR MUCH OF THE EVENT...HOWEVER THE LACK
OF OVERALL BUOYANCY COULD BE OFFSET SOMEWHAT BY THE TENDENCY FOR THE
UPDRAFTS TO ROTATE. LOW LEVEL JET WILL BE STRONGEST 40-50KTS OVER
THE NATURE COAST ZONES...AND THEN WEAKEN WITH SOUTHWARD EXTENSION.
ALL THAT BEING SAID...THE POTENTIAL CERTAINLY EXISTS FOR ISOLATED
SEVERE WEATHER. THE MAIN THREAT WILL BE FOR DAMAGING STRAIGHT-LINE
WINDS. AN ISOLATED TORNADO IS POSSIBLE AS WELL. THE BEST SETUP FOR
AN ISOLATED TORNADO LOOKS TO EXIST ALONG THE I-4 CORRIDOR AND
NORTHWARD THROUGH THE NATURE COAST ZONES WHERE THE MORE PRONOUNCED
LOW LEVEL JET EXISTS...RESULTING IN 0-1KM SHEAR OF 25-30KTS.
WEDNESDAY...UPPER SHORTWAVE TAKES ON AN INCREASINGLY NEGATIVE TILT
AND ROTATES TO THE NORTHEAST OF THE AREA DURING THE MORNING HOURS.
RAIN WILL BE OVER WITH THE COLD FRONT OFF TO OUR EAST BY SUNRISE.
DEEP LAYER MOISTURE WILL ALSO QUICKLY EXIT ALLOWING FOR GENERALLY
CLEARING SKIES. HOWEVER...CAA IN THE WAKE OF THE FRONT OVER THE GULF
WILL LIKELY PRODUCE SOME COLD AIR STRATOCU THAT MAY MIGRATE ONSHORE
FROM TIME TO TIME (ESPECIALLY FROM PINELLAS COUNTY SOUTHWARD). THOSE
TRAVELING FOR THE THANKSGIVING HOLIDAY ON WEDNESDAY ALONG I-4 OR
FLORIDA I-75 CORRIDORS SHOULD EXPERIENCE FAIR WEATHER WITH A GUSTY
NW WIND. HIGH TEMPERATURES WILL BE COOLER WITH MAINLY 60S FROM TAMPA
BAY NORTHWARD AND AROUND 70 FURTHER SOUTH. ALONG AREA BEACHES THE
STRONG ONSHORE FLOW WILL PRODUCE LARGE BREAKING WAVES AND A HIGH
RISK OF RIP CURRENTS THROUGH THE DAY.
WEDNESDAY NIGHT...
LIKELY THE COLDEST NIGHT OF THE SEASON SO FAR ON THE WAY. A VERY DRY
AIRMASS AND NORTHERLY FLOW DRAINING DOWN THE PENINSULA WILL ALLOW
FOR TEMPERATURES TO STEADILY FALL THROUGH THE NIGHT. BY DAWN ON
THANKSGIVING MORNING THE CURRENT FORECAST SHOWS WIDESPREAD LOW TEMPS
IN THE MID/UPPER 30S TO LOW 40S. COLDER LOCATIONS OF HILLSBOROUGH...
POLK...AND PASCO COUNTY MAY BRIEFLY REACH THE LOWER 30S...AND EVEN
BETTER CHANCES FOR A PERIOD OF SUB-FREEZING (UPPER 20S/LOW 30S)
FURTHER NORTH ALONG THE NATURE COAST. THE CURRENT FORECAST
TEMPERATURES ARE SEVERAL DEGREES ABOVE THE MAV GUIDANCE AS
EXPERIENCE SHOWS A COLD BIAS TO THE STATISTICAL GUIDANCE WITH
REGARDS TO ADVECTION EVENTS. EVEN WITH THIS BIAS ADJUSTMENT...A
FREEZE WATCH IS APPROPRIATE...AND HAS BEEN ISSUED FOR HERNANDO...
SUMTER...CITRUS...AND LEVY DURING THE EARLY MORNING HOURS OF
THURSDAY (THANKSGIVING MORNING).
THANKSGIVING DAY/NIGHT...
A COLD START...BUT OTHERWISE A PLEASANT HOLIDAY UPCOMING. THE
SYNOPTIC PATTERN LOOKS BENIGN WITH ZONAL FLOW ALOFT AND A NORTHEAST
LOW LEVEL FLOW ON THE SOUTH SIDE OF SURFACE RIDGING. PLENTY OF SUN
IN THE MORNING WILL GIVE WAY TO A MIX OF SUN AND CLOUDS FOR THE
AFTERNOON AND TEMPERATURES RISING INTO THE 60S FOR MOST SPOTS
(PERHAPS NEAR 70 AROUND FORT MYERS). INCREASING LOW LEVEL MOISTURE
OFF THE ATLANTIC BY THURSDAY NIGHT SHOULD PREVENT ANY FREEZE
CONCERNS AS TEMPERATURES LOOK TO BE A GOOD 5-10+ DEGREES WARMER FOR
LOWS THAN ON THURSDAY MORNING.
&&
.LONG TERM (FRIDAY-MONDAY)...
SYNOPTIC MID LEVEL PATTERN THROUGH THE WEEKEND SHOWS A ZONAL FLOW
IN PLACE FRIDAY WITH A WEAK SHORT WAVE SHIFTING THROUGH THE
PENINSULA ON SATURDAY. ECMWF IS SHOWING A MORE AMPLIFIED TROUGH
DIGGING SOUTH THROUGH THE SOUTHEAST US ON MONDAY WITH THE GFS
DEPICTING A MUCH WEAKER WAVE. AT THE SURFACE...MODELS ARE IN GOOD
AGREEMENT THROUGH SUNDAY SHOWING HIGH PRESSURE STRETCHED ACROSS
THE EAST COAST BEFORE BEING FORCED EASTWARD BY THE NEXT
APPROACHING COLD FRONT.
DRY PATTERN EXPECTED TO SETTLE IN THROUGH SUNDAY MORNING WHICH WILL
LIMIT RAIN CHANCES. EVEN WITH A MID LEVEL SHORT WAVE SHIFTING
THROUGH THE STATE ON SATURDAY STRONG SURFACE RIDGING AND LACK OF
MOISTURE WILL HELP DIMINISH CONVECTION. RIDGE BEGINS TO WEAKEN ON
SUNDAY AND MONDAY WITH THE RETURN OF A MORE SOUTHEASTERLY FLOW. AS
MOISTURE BEGINS TO ADVECT OVER THE STATE WE WILL SEE RAIN CHANCES
BEGIN TO SLIGHTLY INCREASE AT THE TAIL END OF THE LONG TERM PERIOD.
TEMPS WILL GRADUALLY INCREASE TO MORE SEASONAL VALUES THROUGH
WEEKEND.
&&
.AVIATION...
BKN CIGS WITH VCNTY SHRA OR TSRA THIS AFTERNOON GIVE WAY TO MVFR IN
TSRA BEGINNING 00Z-04Z...WITH OCNL IFR...AND ENDING 06Z-08Z. VCNTY
SHRA OR -RA BECOME JUST BKN VFR CIGS AFTER 12Z. GUSTY SOUTHERLY
WINDS GRADUALLY SHIFT TO WESTERLY BY SUNRISE.
&&
.MARINE...
LOW PRESSURE WILL PASS TO OUR NORTH ACROSS SOUTHERN ALABAMA AND
GEORGIA THIS EVENING...AND TO THE MID ATLANTIC STATES BY WEDNESDAY.
A STRONG COLD FRONT TRAILING FROM THIS LOW WILL MOVE ACROSS THE
EASTERN GULF OF MEXICO THIS EVENING AND OVERNIGHT. WINDS WILL SHIFT
NORTHWEST IN THE WAKE OF THE FRONT WITH GUSTS TO GALE FORCE POSSIBLE
AFTER MIDNIGHT THROUGH WEDNESDAY MORNING. HIGH PRESSURE WILL ALSO
BUILD NORTH OF THE AREA IN THE WAKE OF THE FRONT AND REMAIN IN PLACE
THROUGH FRIDAY. WINDS AND SEAS WILL REMAIN NEAR ADVISORY CONDITIONS
THROUGH FRIDAY DUE TO A TIGHT PRESSURE GRADIENT TO THE SOUTH OF THE
HIGH CENTER.
&&
.FIRE WEATHER...
A STRONG COLD FRONT WILL CROSS THE REGION OVERNIGHT WITH A MUCH
COOLER AND DRIER AIRMASS ARRIVING DURING THE DAY ON WEDNESDAY. WINDS
WILL BE QUITE GUSTY FROM THE NORTHWEST DURING WEDNESDAY RESULTING IN
HIGH DISPERSION INDICES ACROSS THE FORECAST AREA. HOWEVER...AT THIS
TIME...NO CRITICAL LEVELS OF RELATIVE HUMIDITY ARE ANTICIPATED.
WINDS WILL BECOME LESS GUSTY FROM THE NORTHEAST ON THURSDAY AND A
BRIEF PERIOD OF RELATIVE HUMIDITY BELOW 35 PERCENT IS POSSIBLE
DURING THE AFTERNOON...ESPECIALLY TO THE NORTH OF THE I-4 CORRIDOR.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 66 69 39 67 / 100 10 0 0
FMY 70 74 43 71 / 90 10 0 0
GIF 63 69 37 68 / 90 10 0 0
SRQ 66 71 42 67 / 90 10 0 0
BKV 62 67 34 66 / 100 10 0 0
SPG 66 69 46 66 / 100 10 0 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...RIP CURRENT RISK THROUGH THURSDAY MORNING FOR CHARLOTTE-
HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.
HIGH SURF ADVISORY UNTIL 7 AM EST THURSDAY FOR CHARLOTTE-
HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.
FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
MORNING FOR CITRUS-HERNANDO-LEVY-SUMTER.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR BONITA
BEACH TO ENGLEWOOD OUT 20 NM-BONITA BEACH TO
ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD TO TARPON SPRINGS
OUT 20 NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60 NM-
TARPON SPRINGS TO SUWANNEE RIVER OUT 20 NM-TARPON
SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 10 PM EST WEDNESDAY FOR TAMPA
BAY WATERS.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
AVIATION...RUDE
LONG TERM...BARRON
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
925 AM EST TUE NOV 26 2013
...ISOLATED SEVERE WEATHER POSSIBLE THIS EVENING AND OVERNIGHT...
.UPDATE (REST OF TODAY THROUGH WEDNESDAY MORNING)...
14Z WATER VAPOR AND H4 RAP ANALYSIS SHOWING AN AMPLIFIED AND HIGHLY
ENERGETIC UPPER LEVEL PATTERN EVOLVING ACROSS THE CONUS. FLOW RIDGES
SHARPLY OVER THE PACIFIC COAST AND INTER-MOUNTAIN WEST BEFORE DIVING
BACK SOUTH INTO DEEP LONGWAVE TROUGHING COVERING THE REMAINDER OF
THE NATION. THIS LONGWAVE TROUGH IS RATHER COMPLEX WITH BOTH A
STRONG NORTHERN STREAM AND SOUTHERN STREAM IMPULSE EMBEDDED WITHIN.
THE NORTHERN STREAM ENERGY IS DROPPING QUICKLY SOUTHEASTWARD OVER
THE UPPER MIDWEST/GREAT LAKES WHILE THE SOUTHERN STREAM IMPULSE IS
CURRENTLY EJECTING EASTWARD OVER THE WESTERN GULF OF MEXICO FROM THE
SOUTHERN PLAINS.
IT IS THIS POTENT SOUTHERN STREAM IMPULSE WHICH WILL BE THE BIG
PLAYER IN OUR WEATHER OVER THE NEXT 24 HOURS AS IT SWINGS EASTWARD
ALONG THE NORTHERN GULF COAST.
CURRENTLY AT THE SURFACE...THE FLORIDA PENINSULA RESIDES WITH A ZONE
OF MODERATE SOUTHEASTERLY FLOW TO THE SOUTH OF A EAST-WEST ORIENTED
WARM FRONT ALIGNED NEAR THE I-10 CORRIDOR. THIS WARM FRONT TRAILS
BACK TO AN AREA OF LOW PRESSURE NEAR AL COAST. FROM THIS LOW...A
COLD FRONT TRAILS SOUTHWARD ACROSS THE CENTRAL GULF OF MEXICO AND
WILL MOVE QUICKLY EASTWARD TO CROSS OUR FORECAST AREA TONIGHT.
REGIONAL RADARS SHOWING WIDESPREAD SHOWERS/RAIN ASSOCIATED WITH THE
UPGLIDE OVER THE WARM FRONT LIFTING QUICKLY NORTHWARD. MUCH OF THE
FORECAST AREA IS NOW LEFT IN A ZONE OF WEAKER LIFT AS WE AWAIT THE
SYNOPTIC FORCING ASSOCIATED WITH THE APPROACHING IMPULSE/TROUGH
LATER TODAY AND TONIGHT. THEREFORE...FOR A MAJORITY OF THE DAY...THE
SHOWER ACTIVITY WILL BE MORE SCATTERED "OFF AND ON" TYPE OF REGIME
AS OPPOSED TO THE STEADIER PRECIP THAT THE CENTRAL AND NORTHERN
ZONES SAW EARLIER IN THE MORNING. SKIES ARE MOSTLY CLOUDY TO CLOUDY
REGION-WIDE AND ZONES FROM TAMPA NORTHWARD ARE LIKELY TO REMAIN
MOSTLY CLOUDY THROUGH THE DAY. FARTHER SOUTH FROM THE WARM FRONT
OVER OUR SOUTHERN ZONES...WILL NOT BE SURPRISED TO SEE AT LEAST SOME
SUNNY BREAKS EVENTUALLY DEVELOP. ALTHOUGH...THE ADDED INSTABILITY
FROM ANY INSOLATION WOULD LIKELY RESULT IN MORE SCATTERED SHOWERS.
THE POTENTIALLY MORE SIGNIFICANT WEATHER WILL BEGIN TO APPROACH
FROM THE EASTERN GULF OF MEXICO LATE THIS AFTERNOON/EARLY EVENING.
AS WE HEAD THROUGH THE LATER AFTERNOON AND ESPECIALLY THE EVENING
HOURS...LARGE SCALE FORCING FOR ASCENT ASSOCIATED WITH DCVA/HEIGHT
FALLS WILL OVERSPREAD THE AREA. GFS/ECMWF BOTH SHOW A BROAD EXPANSE
OF DEEP LAYER QG FORCING IN PLACE THIS EVENING. THIS IS ONE OF THE
MORE POTENT MID/UPPER LEVEL IMPULSES THAT WE HAVE SEEN MOVE ACROSS
THE NE GULF IN SOME TIME. UPPER LEVEL PV ANOMALY ASSOCIATED WITH
THIS IMPULSE IS VERY IMPRESSIVE WITH THE DYNAMIC TROPOPAUSE FOLDED
DOWN ALMOST TO 600MB RESULTING IN AN EQUALLY IMPRESSIVE MID/UPPER
LEVEL JET STRUCTURE. SURFACE LOW REFLECTION AS A RESULT SHOULD
CONTINUE TO DEEPEN THROUGH THE DAY/EVENING AHEAD OF THIS FEATURE AS
IT CROSSES INTO SOUTHERN GA. THE COLD FRONT WILL ALSO
INTENSIFY/SHARPEN WITH TIME ADDING A LOWER LEVEL CONVERGENCE FOCUS.
ALL THAT BEING SAID...WOULD EXPECT MOST (IF NOT ALL) LOCATIONS TO
SEE A SECONDARY ROUND OR 2 OF SHOWERS/STORMS BEGINNING LATE THIS
AFTERNOON INTO THE EVENING AND THEN ENDING QUICKLY FROM WEST TO
EAST DURING THE OVERNIGHT AS THE COLD FRONT SWEEPS ACROSS. RAIN
CHANCES ARE CATEGORICAL 80% OR HIGHER FOR JUST ABOUT ALL ZONES THIS
EVENING/OVERNIGHT...BUT TAPER QUICKLY AFTER 2AM...AND HAVE REMOVED
ALL RAIN CHANCES (EVEN FOR OUR FAR EASTERN ZONES) BY SUNRISE
TOMORROW MORNING. THE CONVECTIVE START AND END TIMES AGREE WELL WITH
THE ENSEMBLE SUITE OF LOCAL/NATIONAL HIGH RESOLUTION MODELS AND ALSO
THE HOPWRF ENSEMBLES BEING RUN OVER THE SE CONUS TODAY.
SEVERE THREAT...DESPITE THE EXPECTED WIDESPREAD COVERAGE OF SHOWER
AND STORMS DUE TO THE FORCING...THE OVERALL SEVERE THREAT SHOULD BE
ISOLATED IN NATURE. THE STORM PREDICTION CENTER HAS OUTLOOKED MUCH
OF OUR AREA IN A SLIGHT RISK FOR SEVERE WEATHER AND AGREE WITH THIS
ASSESSMENT. DEEP LAYER 0-6KM BULK SHEAR (35-40KTS) AND MLCAPE
(250-500 J/KG) IS NOT OVERLY IMPRESSIVE FOR OUR ZONES...BUT
SUFFICIENT FOR ORGANIZED CONVECTION. MID-LEVEL LAPSE RATES ARE POOR
FOR MUCH OF THE EVENT...HOWEVER THE LACK OF OVERALL BUOYANCY COULD
BE OFFSET SOMEWHAT BY THE TENDENCY FOR THE UPDRAFTS TO ROTATE. LOW
LEVEL JET WILL BE STRONGEST 40-50KTS OVER THE NATURE COAST
ZONES...AND THEN WEAKEN WITH SOUTHWARD EXTENSION. ALL THIS BEING
SAID...THE POTENTIAL CERTAINLY EXISTS FOR ISOLATED SEVERE WEATHER.
THE MAIN THREAT WILL BE FOR DAMAGING STRAIGHT-LINE WINDS. AN
ISOLATED TORNADO IS POSSIBLE AS WELL. THE BEST SETUP FOR AN ISOLATED
TORNADO LOOKS TO EXIST OVER THE NATURE COAST ZONES WHERE THE MORE
PRONOUNCED LOW LEVEL JET EXISTS RESULTING IN 0-1KM SHEAR OF AROUND
30KTS.
UPPER SHORTWAVE TAKES ON AN INCREASINGLY NEGATIVE TILT AND ROTATES
TO THE NORTHEAST OF THE AREA DURING WEDNESDAY MORNING. RAIN WILL BE
OVER WITH THE COLD FRONT OFF TO OUR EAST BY SUNRISE. DEEP LAYER
MOISTURE WILL ALSO QUICKLY EXIT ALLOWING FOR GENERALLY CLEARING
SKIES. HOWEVER...CAA IN THE WAKE OF THE FRONT OVER THE GULF WILL
LIKELY PRODUCE SOME COLD AIR STRATOCU THAT MAY MIGRATE ONSHORE FROM
TIME TO TIME (ESPECIALLY FROM PINELLAS COUNTY SOUTHWARD). THOSE
TRAVELING FOR THE THANKSGIVING HOLIDAY ON WEDNESDAY ALONG I-4 OR
FLORIDA I-75 CORRIDORS SHOULD EXPERIENCE FAIR WEATHER WITH A GUSTY
NW WIND. HIGH TEMPERATURES WILL BE COOLER WITH MAINLY 60S FROM TAMPA
BAY NORTHWARD AND AROUND 70 FURTHER SOUTH.
&&
.AVIATION...
BKN CIGS...OCNL MVFR/IFR...WITH SHRA OR -RA THROUGH MID MORNING. AN
ADVANCING FRONTAL SYSTEM WILL BRING VCTS BEGINNING AROUND 8-20Z WITH
TSRA STARTING BETWEEN 00-04Z...WITH TEMPO MVFR/IFR EXPECTED. GUSTY
WINDS SHIFT TO WEST AND NW AS THE FRONT MOVES ACROSS TONIGHT.
&&
.MARINE...
A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR ALL COASTAL WATERS
THROUGH WEDNESDAY EVENING...BUT THIS WILL LIKELY BE EXTENDED. SOME
AREAS COULD SEE WINDS THAT DROP BELOW ADVISORY LEVELS FOR A BRIEF
TIME...ESPECIALLY LATER THIS MORNING BETWEEN THE WARM AND COLD
FRONTAL PASSAGES...BUT THEY WILL INCREASE RAPIDLY AGAIN WITH THE
COLD FRONT OVERNIGHT INTO WEDNESDAY MORNING. BUFKIT SOUNDING
PROFILES SHOWING IMPRESSIVE LOW LEVEL LAPSE RATES OVER THE WATER
BEHIND THE FRONT WHICH WILL ALLOW FOR HIGHLY EFFICIENT MIXING OF
DOWNWARD MOMENTUM AND LIKELY AT LEAST A PERIOD OF HIGH END
ADVISORY WINDS WEDNESDAY MORNING. SEAS WILL REACH UP TO 10 FEET OR
SO OFFSHORE BY EARLY WEDNESDAY MORNING. CONDITIONS WILL IMPROVE
TOWARD THE END OF THE WEEK...BUT WE COULD STILL SEE WIND SPEEDS
CLOSE TO CAUTIONARY OR ADVISORY LEVELS THROUGH SATURDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 81 64 68 39 / 70 100 10 10
FMY 82 69 73 44 / 50 90 10 10
GIF 79 63 69 39 / 90 90 10 10
SRQ 82 67 70 43 / 60 90 10 10
BKV 79 62 65 32 / 90 100 10 10
SPG 80 65 67 47 / 70 100 10 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...RIP CURRENT RISK FROM 1 PM EST THIS AFTERNOON THROUGH
WEDNESDAY EVENING FOR CHARLOTTE-HILLSBOROUGH-LEE-
MANATEE-PINELLAS-SARASOTA.
HIGH SURF ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EST
WEDNESDAY FOR CHARLOTTE-HILLSBOROUGH-LEE-MANATEE-
PINELLAS-SARASOTA.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 10 PM EST WEDNESDAY FOR
BONITA BEACH TO ENGLEWOOD OUT 20 NM-BONITA BEACH TO
ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD TO TARPON SPRINGS
OUT 20 NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60 NM-
TAMPA BAY WATERS-TARPON SPRINGS TO SUWANNEE RIVER OUT
20 NM-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 TO 60
NM.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1229 AM EST TUE NOV 26 2013
.SYNOPSIS...
MOISTURE WILL OVERSPREAD THE FORECAST AREA TONIGHT AHEAD OF LOW
PRESSURE DEVELOPING ALONG THE GULF COAST. THE LOW WILL MOVE
NORTHEAST ACROSS THE OUR AREA TUESDAY AND TUESDAY NIGHT...BRINGING
WIDESPREAD RAIN. THE LOW WILL LIFT NORTHEAST OF THE REGION
WEDNESDAY WITH COLD AND DRY HIGH PRESSURE RETURNING THANKSGIVING
DAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
HIGH PRESSURE CENTERED OVER THE MID-ATLANTIC COAST WILL MOVE EAST
AS A WEATHER SYSTEM DEVELOPS ALONG THE GULF COAST OF LOUISIANA.
LOWER CLOUDS NOW BLANKETING THE ENTIRE FA.
WATER VAPOR IMAGERY AND MSAS ANALYSIS SHOWING A DIFLUENT PATTERN
OVER THE WESTERN GULF OF MEXICO AND LOW PRESSURE HAS NOW DEVELOPED ALONG
THE GULF COAST. ALL MODELS INDICATE INCREASING ISENTROPIC LIFT
AHEAD OF THIS LOW WILL RESULT IN PRECIPITATION OVERSPREADING THE
FORECAST AREA FROM SOUTHWEST TO NORTHEAST TONIGHT. THE HRRR PLUS
SATELLITE AND RADAR TRENDS INDICATE THE PRECIPITATION WILL HOLD
OFF UNTIL THE OVERNIGHT HOURS. THE MODELS INDICATE ENOUGH WARMING
SHOULD OCCUR FOR ALL LIQUID PRECIPITATION. ALL SREF MEMBERS KEEP
THE SURFACE TEMPERATURE ABOVE FREEZING LATE TONIGHT...EVEN IN THE
NORTH PART. FREEZING RAIN IS NOT IMPOSSIBLE IN THE EXTREME NORTH
SECTION...BUT BELIEVE PRECIPITATION WILL BE LIGHT AT THE ONSET
LIMITING WET-BULB COOLING. ALSO...THE NAM AND GFS SHOW SURFACE
WET-BULB TEMPERATURES RISING ABOVE FREEZING BEFORE SIGNIFICANT
PRECIPITATION REACHES THE AREA LATE TONIGHT. DESPITE THE MODEL
GUIDANCE...THERE MAY BE LAYERS OF DRY AIR ALOFT WITH WET-BULB
COOLING WHICH COULD SUPPORT SLEET...MAINLY IN THE EXTREME NW
PORTIONS OF THE FA. BELIEVE ANY SLEET WOULD BE LIGHT AND WITH
SURFACE TEMPERATURES ABOVE FREEZING...SO NO ACCUMULATION SHOULD
OCCUR.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/...
TUESDAY THROUGH WEDNESDAY...THE NAM AND GFS INDICATE THE BULK OF
THE RAINFALL WILL OCCUR DURING THE TUESDAY AND TUESDAY NIGHT TIME
FRAME WITH STRONG ISENTROPIC LIFT AND APPROACHING H5 SHORTWAVE
TROUGH. THE NAM...GFS AND SREF MEAN SUPPORT TOTAL RAINFALL FROM
1.5 TO AROUND 2.0 INCHES. THE NAM SHOWS CROSS TOTALS NEAR 25
TUESDAY AND TUESDAY NIGHT...SO A FEW ELEVATED THUNDERSTORMS MAY
OCCUR. THE SURFACE LOW WILL BE NORTHEAST OF THE AREA WITH THE
UPPER TROUGH OVERHEAD WEDNESDAY. WE MAY HAVE LINGERING MORNING
RAIN. STRONG COLD ADVECTION AND DRY AIR WILL POUR INTO THE AREA
WEDNESDAY AFTERNOON.
THE NAM LI-PATTERN INDICATES A WEDGE-TYPE PATTERN TUESDAY. WE
LEANED TOWARD THE IN-HOUSE WEDGE SCHEME FOR THE HIGH TEMPERATURE
FORECAST. EXPECT A NEAR STEADY TEMPERATURE TUESDAY NIGHT. USED
THE COLDER TEMPERATURE GUIDANCE WEDNESDAY BECAUSE OF LINGERING
CLOUDINESS AND A SHARP UPPER TROUGH OVER OUR AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING DRY HIGH PRESSURE
DOMINATING DURING MUCH OF THE THE MEDIUM-RANGE PERIOD. AN ONSHORE
FLOW AND WARM FRONT MAY SUPPORT RAIN MONDAY. BELOW NORMAL
TEMPERATURES SHOULD CONTINUE THROUGH SUNDAY. THE GFS...ECMWF...EKD MOS
PLUS GFS ENSEMBLE MEAN SUPPORT TEMPERATURES AROUND 10 DEGREES
BELOW NORMAL THROUGH SUNDAY WITH NORMAL TEMPERATURES MONDAY.
&&
.AVIATION /06Z TUESDAY THROUGH SUNDAY/...
MVFR CONDITIONS THROUGH MOST OF THE OVERNIGHT PERIOD THEN
DETERIORATING TO IFR BY 12Z.
HIGH PRESSURE WILL CONTINUE TO WEAKEN AND SHIFT EAST INTO THE
ATLANTIC AS LOW PRESSURE ALONG THE GULF COAST PUSHES NORTHEASTWARD.
DUE TO MOISTURE FLUX INTO THE AREA AHEAD OF THE APPROACHING
WEATHER SYSTEM...CEILINGS HAVE LOWERED TO MVFR AT ALL TAF SITES.
LIGHT RAIN SHOULD SPREAD INTO THE AREA BETWEEN 08Z AND 10Z AND
CONTINUE SPREADING TOWARD THE NORTHEAST AS THE SURFACE LOW
APPROACHES. BY 12Z...WIDESPREAD RAINFALL IS EXPECTED AND CONDITIONS
SHOULD DETERIORATE RAPIDLY TO IFR. MAINLY MODERATE RAIN ON TUESDAY
BUT CANNOT RULE OUT SOME HEAVY RAIN AT TIMES. MODEL SOUNDINGS AND
LOCAL SCHEME SHOWING WIND SHEAR DEVELOPING TUESDAY MORNING.
INTRODUCED WIND SHEAR OF 35 KNOTS FROM 12Z TO 24Z. ALSO WITH
INCREASING INSTABILITY ALOFT...A FEW ELEVATED THUNDERSTORMS ARE
POSSIBLE...ESPECIALLY ACROSS THE EASTERN MIDLANDS TAF SITE OGB...BUT
CONFIDENCE WAS TOO LOW TO INCLUDE IN THIS TAF PACKAGE.
EXTENDED AVIATION OUTLOOK...AN EXTENDED PERIOD OF CIG/VSBY
RESTRICTIONS ARE POSSIBLE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS A
LOW PRESSURE SYSTEM FROM THE GULF OF MEX CROSSES THE SOUTHEASTERN
STATES.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
156 AM EST TUE NOV 26 2013
.SYNOPSIS...
ISSUED AT 154 AM EST TUE NOV 26 2013
A REINFORCING SHOT OF COLD AIR WILL SET THE STAGE FOR A POTENTIAL
HEAVY LAKE EFFECT SNOW EVENT TUESDAY NIGHT THROUGH WEDNESDAY
ACROSS FAR SOUTHWEST LOWER MICHIGAN AND PORTIONS OF NORTHWEST AND
NORTH CENTRAL INDIANA.
&&
.UPDATE...
ISSUED AT 700 PM EST MON NOV 25 2013
LEAD SHORTWAVE APPEARS TO BE QUITE SHEARED IN NATURE STRETCHING
FROM SOUTHERN LOWER MICHIGAN BACK INTO CENTRAL ILLINOIS THIS
EVENING. THIS WAVE WILL CONTINUE TO SLIDE EAST THROUGH THE AREA
THROUGH THE LATE EVENING. THE COMBINATION OF WEAK DPVA WITH THIS
FEATURE AND ASSOCIATED DOWNSTREAM WEAK 750-650 HPA FRONTOGENESIS
WILL SUPPORT AREA OF -SN OVERSPREADING MUCH OF EASTERN AND
SOUTHEAST PORTIONS OF THE AREA THROUGH MIDNIGHT. DRY NATURE TO AIR
MASS AND ELEVATED NATURE OF FORCING WILL ONLY LEAD TO A FEW TENTHS
OF SNOW ACCUMULATION FOR MOST LOCATIONS HOWEVER. MUCH DRIER MID
LEVEL AIR ADVECTING IN BEHIND THIS LEAD SHORT WAVE HAS CUT OFF
PRECIP ACROSS THE FAR NORTH EARLY THIS EVENING. WATER VAPOR
IMAGERY/21Z RAP INITIALIZATION DO SUGGEST PRESENCE OF NEXT
UPSTREAM VORT ACROSS SOUTHERN MINNESOTA WHICH WILL SLIDE INTO THE
WESTERN GREAT LAKES LATE TONIGHT. NOT COMPLETELY OUT OF THE
QUESTION THAT SOME PATCHY FREEZING DRIZZLE COULD ACCOMPANY THIS
WEAK FORCING...BUT GIVEN EXPECTED VERY LIGHT NATURE TO THE DRIZZLE
IF IT OCCURS WOULD EXPECT MINIMAL TO NO IMPACT SO WILL CONTINUE TO
OMIT FROM THE FORECAST. ONLY TWEAK TO PREVIOUS FORECAST WAS TO
INCREASE POPS SLIGHTLY ACROSS CENTRAL PORTIONS OF THE AREA WHERE
IT APPEARS SOME VERY WEAK ELEVATED FGEN RESPONSE HAS OCCURRED OVER
THE PAST HOUR OR TWO. EVEN ACROSS THESE LOCATIONS...ACCUMULATIONS
SHOULD ONLY TOTAL A TENTH OR TWO. ANOTHER WEAK WAVE FROM SOUTHERN
STREAM ACROSS CENTRAL ILLINOIS EVIDENT ON WATER VAPOR IMAGERY MAY
CLIP SOUTHERN PORTIONS OF FORECAST THROUGH EARLY PORTIONS OF THE
OVERNIGHT THAT COULD LEAD TO BRIEF ENHANCEMENT OF WEAK ELEVATED
FGEN...BUT LITTLE OR NO ACCUMULATION IS EXPECTED. TREND OF
DIMINISHING POPS FROM NORTHWEST TO SOUTHEAST STILL APPEARS
REASONABLE AND NO OTHER CHANGES MADE TO PREVIOUS FORECAST AT THIS
TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 340 PM EST MON NOV 25 2013
LEAD NORTHERN STREAM S/W CURRENTLY DIVING SOUTHEAST ACROSS UPPER
GREAT LAKES. WEAK SMALLER SCALE WAVES STREAMING NORTHEAST TOWARD THE
LOWER GREAT LAKES NOTED ON W/V IMAGERY THIS AFTN...EMANATING FROM
STRONG SOUTHERN LOW ACROSS PANHANDLE REGION. THE PHASING OF THESE
WEAKER P/V ANOMALIES ACROSS THE AREA...COMBINED WITH COMPACT
CORRIDOR OF DECENT ISENTROPIC LIFT...PROVIDING WIDESPREAD
PRECIPITATION ACROSS THE REGION PER RADAR. THESE SNOW SHOWERS HAVE
BEEN STRUGGLING TO REACH THE GROUND ALL DAY PER UPSTREAM SFC
OBS...GIVEN STOUT DRY BOUNDARY LAYER AND SFC DEWPOINT DEPRESSIONS ON
THE ORDER OF 10-15F. CONTINUED WITH PREVIOUS FCST TREND...MENTIONING
LIGHT SNOW WORDING/FLURRIES...ALONG WITH LIGHT ACCUMULATIONS ACROSS
THE AREA. CONFIDENCE HAS WANED FOR ANY ACCUMULATIONS GIVEN RADAR
TRENDS...HOWEVER STREAM OF MID LVL MOISTURE ADVECTING NE INTO THE
AREA NOTED ON W/V MAY LEND TO ENHANCE THESE RETURNS AND HELP TOP DOWN
SATURATION OF THE LAYER...COINCIDENT WITH THE CORRIDOR OF ISENTROPIC
LIFT.
CORRIDOR OF LIFT STRETCHES OFF TO THE EAST AFTER MIDNIGHT...WITH
DIMINISHING POPS REFLECTED IN THE GRIDS. STRONGER NORTHERN STREAM
P/V ANOMALY WILL SURGE SOUTHEAST THROUGH THE REGION ON TUESDAY...AND
WILL ATTEMPT TO PHASE WITH SOUTHERN STREAM P/V ANOMALY LATE TOMORROW
AND WEDNESDAY WELL SOUTHEAST OF THE REGION. ATLANTIC COAST SFC
CYCLONE WILL DEVELOP IN RESPONSE TO THESE FEATURES...AND BRING
WIDESPREAD PRECIP TO MUCH OF THE EASTERN US. HOWEVER...BEST
ISENTROPIC UPGLIDE SHOULD KEEP SNOWFALL SOUTH AND EAST OF THE AREA
THROUGH TUESDAY...ESPECIALLY GIVEN THE AGGRESSIVE NATURE OF THE
NORTHERN STREAM ENERGY SURGING SOUTHEAST THROUGH THE AREA.
THEREFORE...HAVE KEPT POPS OUT OF THE TUESDAY PERIOD ACROSS THE
SOUTHEAST PORTION OF THE AREA...BUT HEDGED WITH A CHANCE FLURRIES
MENTION CLOSE TO THE EDGE OF THE BEST MOISTURE/LIFT GRADIENTS. NO
MAJOR CHANCES TO TEMPS TONIGHT/TUESDAY.
ACCOMPANYING THIS STRONG NORTHERN P/V ANOMALY IS ANOTHER EARLY
SEASON SURGE OF ARCTIC AIR. THIS WILL PUSH THROUGH THE AREA TUESDAY
AFTERNOON. KEPT WITH A FLURRY MENTION ACROSS THE AREA IN THE
AFTERNOON IN THE WAKE OF THE ARCTIC FRONT. LAKE RESPONSE SHOULD
ACTIVATE TUESDAY AFTERNOON AS 850MB TEMPS CRASH TO -12C TO -13C BY
21Z TUESDAY. SHOULD BE RATHER DISORGANIZED BEFORE 00Z...AS LOW LVL
NORTHWEST FLOW SHOULD KEEP BANDING TO A MINIMUM DURING THIS PERIOD.
WENT WITH A FEW TENTHS OF SNOW ACCUMULATION ACROSS FAR SW LWR MI
FROM 18Z TO 00Z...BEFORE FLOW VEERS NORTHERLY INTO THE
OVERNIGHT...LEADING TO A SIGNIFICANT SINGLE BAND EVENT IN THE LONG
TERM PERIOD.
&&
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 340 PM EST MON NOV 25 2013
...SIGNIFICANT LAKE EFFECT SNOW EXPECTED TUE NIGHT-WED...
FCST THIS AFTN PREDICATED ON SHARPER H5 SOLUTIONS ALOFT INCLUDING
NAM/GEM/EC AND VARIOUS HIGHRES GUIDANCE AS POTENT SRN STREAM SW
PHASES W/SECONDARY NRN STREAM DROPPING SWD THROUGH NRN SK THIS AFTN.
VIGOROUS/SHARP LL CAA BURST XPCD TUE NIGHT W/DEEP NRLY LONG AXIS
FETCH DVLPG. CLEAR INDICATIONS OF LK SP CONNECTION WHICH WILL MOST
CERTAINLY AID IN BREATH OF LATENT MSTR FLUX AND MODULATE SNOWBAND
INTENSITY HIGHER. 30-35KT MEAN CLD BEARING LYR FLW SHLD ALSO YIELD A
FURTHER INLAND PENETRATION OF SNOWBANDS BUT WHERE REMAINS A BIG QN.
TYPICAL W-E SPREAD NOTED THIS AFTN ALTHOUGH A DECIDED CONSENSUS LIES
W/ERN CLUSTER OF SOLUTIONS INCLUDING MOST HIGHRES RENDITIONS ALG
W/GEM AND 4KM NAM. AT THIS POINT GIVEN HOLIDAY TRAVEL CONCERNS WILL
BROAD BRUSH A WATCH FOR LT TUE NIGHT-WED EVE ACRS MUCH OF THE WRN
CORNER. HWVR IMPACTS WILL LIKELY EXTEND FARTHER DOWNSTREAM AND WILL
ADDRESS IN HWO UPDATE.
FVRBL DGZ LOCATION WITHIN LVL OF NON DVRG NOTED IN XSCTNS ALG
W/MAXIMIZED RH AND STG ASCENT WOULD PORTEND A PD OF 1-2 INCH SNOWFALL
RATES LIKELY VRY LT TUE NIGHT INTO WED AFTN BFR WKNG. CONSERVATIVE
AGGREGATED QPF YIELDS A BROAD 6-10 INCH SNOW PLUME W/OBVIOUS HEAVIER
ACCUMS TIED TO PLACEMENT OF LK SP CONNECTED PLUME AND LESSOR ACCUMS
TIED TO WHERE WEAKER WRN DIPOLE DVLPS. BAND XPCD TO BREAKUP RAPIDLY
WED EVE IN RESPONSE TO QUICK FLATTEN OF FLW ALOFT AS EAST COAST
STORM LIFTS OUT AND AHD OF NXT UPSTREAM DISTURBANCE. TEMPS THROUGH
THE PD CONT COLD BUT MODERATION ON TAP THIS WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 153 AM EST TUE NOV 26 2013
HIGH END MVFR TO VFR MET CONDS PREVAIL OVERNIGHT ACRS NRN IN WITH
FLURRIES COMING TO END AT KFWA SHORTLY. OTHERWISE FOCUS ON
DEVELOPMENT OF SIG LAKE EFFECT SNOWFALL FOR KSBN AREA LATE IN
FORECAST PD. TEMPO FUELING REQUIREMENTS THERE WITH HIGH LIKELIHOOD
OF FURTHER DEGRADATION INTO IFR RANGE IN HEAVIER SNOW
SQUALLS...ESPECIALLY JUST BYND CURRENT FCST PD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...LAKE EFFECT SNOW WATCH FROM LATE TONIGHT THROUGH WEDNESDAY
EVENING FOR INZ003-004-012>015.
MI...LAKE EFFECT SNOW WATCH FROM LATE TONIGHT THROUGH WEDNESDAY
EVENING FOR MIZ077.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR
LMZ043-046.
&&
$$
UPDATE...MARSILI
SYNOPSIS...MURPHY
SHORT TERM...NG
LONG TERM...T
AVIATION...MURPHY
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1157 PM CST Mon Nov 25 2013
.UPDATE...
ISSUED AT 1157 PM CST MON NOV 25 2013
The AVIATION section has been updated for the 06Z TAF issuance.
UPDATE ISSUED AT 742 PM CST MON NOV 25 2013
A slightly more modest change in precipitation chances and other
sensible weather elements (weather, temperature, dewpoint, wind,
etc) for tonight and Tuesday morning, mainly over West Kentucky.
The current wave of precipitation and sub-synoptic lift is moving
out of the area, creating a small droplet size area of rain/mist,
as well as snow over the eastern 1/3 of the WFO PAH County warning
area.
Regional radar mosaic still showing 0 to 15/20 dBZ returns over
Central Arkansas, Southeast Misouri, Southeast Illinois, and into
Northwest Kentucky and Southwest Indiana shortly after 01z (7 pm
CST) this evening. This is coincident with the southern edge of a
differential deformation zone/moisture gradient on the 7.0 micron
(sensitive near 700 mb) and 7.4 micron (sensitive near 850 mb)
GOES Sounder Water Vapor channels. On the 11-3.9 micron GOES IR
difference channel, the aforementioned radar echoes are centered
within the mean plume of ice clouds, serving as seeder-feeder
source region.
The GEM (Canadian), SREF (Short Range Ensemble Forecast),
deterministic 18z GFS numerical guidance are similar to the high
resolution 3km HRRR model guidance for this evening and overnight.
We should see a resurgence of PoPs/Weather from the southwest into
the Missouri Bootheel and Southwest Kentucky after midnight (06z).
A sharp northern PoP/Weather gradient should develop over West
Kentucky after midnight, slowly working east-northeast through 8
am CST Tuesday, then continue to shift east during the day on
Tuesday. By 9 am CST Tuesday, most areas should remain above freezing
over the entire WFO PAH CWA, eliminating any travel concern.
For now, the most concentrated area for travel concerns between 11
pm Monday and 8 am Tuesday will be from Paducah KY (KPAH) and
Owensboro KY (KOWB) southward 25 to 30 miles through 5 am CST,
working slightly more southward another 10 to 15 miles between 5
am - 8 am CST. The combination and duration of temperatures
slightly below freezing, PoPs above 40%, and differential lift may
lead some slight glazing on elevated surface and some roadways.
For now, will issue a longer term Special Weather Statement to
address this area of travel concern, as well as post a Weather
Story graphic on the NWS Paducah web page and social media
outlets. May also highlight in the Hazardous Weather Outlook as well.
Given the marginal nature of the precipitation amounts (between
0.04" - 0.07") it will be a judgement call whether an advisory
will be needed overnight, since critical temperatures will focused
in areas where total precipitation will be less than 0.05" between
11 pm and 8 am CST. Given the effectiveness of de-icing agents
(salt, etc...) most roads should remain in good shape. The only
areas of concern will be any untreated roadways.
&&
.SHORT TERM...(This Evening through Tuesday night)
ISSUED AT 239 PM CST MON NOV 25 2013
Models were obviously too slow with precip onset with this
initial wave. Not an uncommon error. Light sleet, light rain
light snow mix across the area. Most notable precip has been
over west KY and southeast MO, near the TN state line over to
the MO bootheel region. We will maintain our SPS (Special Weather
Statement) approach vs. an advisory. A few slick spots certainly
possible though not getting really any reports of that.
Temperatures per KY mesonet into SEMO at or above freezing even
where precip has occurred. Site near Hickman is down to 32F.
Overall, still not a big deal event.
This lead wave will push the afternoon activity on to the east.
The question then becomes, how much more will we see overnight
into early Tuesday. Will maintain slight better chances overnight
south and east and taper off low chance PoPs NW overnight, and
continue with our SE 1/3 of the area PoPs Tuesday as the
southern and northern stream systems interact and draw moisture
into this area. Should be dry over the remainder of the region
Tuesday. A minimal mix precip type possible tonight into early
Tuesday a.m. Then precip should transition to mainly light
rain. Tuesday night will be dry and colder as arctic high
pressure builds south into the area.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 239 PM CST MON NOV 25 2013
With precipitation having moved east of the PAH forecast area,
Wednesday will see clearing skies as chilly and breezy conditions
persist through the day. With highs only in the lower 30s, wind
chill readings in the morning will start out in the single digits to
around 10 degrees, only improving to the lower 20s by afternoon.
The coldest period of the extended will continue into Wednesday
night, with lows in the middle to upper teens. Northwest winds at 5
to 10 mph in the evening will decrease and gradually turn back to
the southwest by daybreak.
High pressure over the central plains Wednesday will slide east of
the PAH fa by Thursday morning, thus the winds becoming southwest.
Southwest flow will lead to a gradual warm up through the weekend,
though readings will remain below normal. High temperatures on
Thanksgiving will only reach the middle to upper 30s, moderating to
the upper 40s to around 50 degrees Saturday and Sunday. Lows
Saturday night are expected to stay above freezing, which will be
the first night with above freezing temperatures since last
weekend.
ECMWF brings a surface low into the Great Lakes region by 12z
Sunday, dragging a cold front into the Mississippi River valley.
GFS is about 12 hours slower than the ECMWF. ECMWF spreads rain
across much of the PAH fa Saturday night, while GFS holds off until
late Sunday into Sunday night. Went with a compromise, keeping
Saturday night dry then including slight to low chance pops for
mainly southern Illinois and southeast Missouri on Sunday. Went
with chance pops across the entire area Sunday night into Monday.
Fortunately, temperatures look to be warm enough through the event
to keep precip all liquid.
&&
.AVIATION...
ISSUED AT 1157 PM CST MON NOV 25 2013
The upper-level storm system over Texas will shift east and phase
with a northern stream system diving over the Mississippi River by
06Z Wednesday. Lots of moisture will be drawn northward over west
Kentucky tonight, as temperatures reach saturation near the
freezing mark. Most of the precipitation will be in the very low-
levels, so drizzle or freezing drizzle would be the main
precipitation type. Most guidance is indicating a brief window
toward 12Z where deeper saturation may occur. Guidance also
indicates some warming aloft by then, so any snow aloft would likely
melt. Rain or sleet would be the main precipitation type. Will
assume temperatures stay just above freezing, so will keep
rain/sleet combination and not mention freezing rain/drizzle.
Ceilings will likely drop to IFR levels in the east and possibly
at all sites straddling 12Z. Ceilings should lift considerably by
mid-morning. Surface high pressure will build east across the area
through the afternoon, so gusty north winds will spread eastward
across the area. The gustiness will pick up during the evening
throughout the area. Some strato cu ceilings are likely later in
the evening. MVFR levels cannot be ruled out.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
747 AM EST TUE NOV 26 2013
.SYNOPSIS...
EAST COAST BOUND LOW PRESSURE WILL SPREAD A WINTRY MIX OF
PRECIPITATION OVER THE REGION TODAY. THAT PRECIPITATION WILL
CHANGE TO ALL SNOW TONIGHT.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
CONFLUENT FLOW AS WELL AS A TIGHT BAND OF FRONTOGENESIS THAT WAS
WELL SAMPLED ON THE NAM BETWEEN 500 AND 300 MB...WHICH IS ROUGHLY
COINCIDENT WITH THE DENDRITIC GROWTH ZONE HAS RESULTED IN A BAND
OF FAIRLY STEADY SNOWFALL THAT HAS PUSHED SLOWLY FROM SOUTH TO
NORTH ALREADY THIS MORNING FROM ZANESVILLE TO WHEELING TO
PITTSBURGH TO LATROBE. AMOUNTS TO THIS POINT OUT OF THIS BAND HAVE
BEEN ROUGHLY 1.5 TO 3.5 INCHES...HOWEVER RECENT RADAR TRENDS AS
WELL AS MODEL TRENDS SUGGEST THIS BAND IS LIKELY TO STRENGTHEN AS
A WARMER PUSH OF AIR ALOFT IS SET TO ADVANCE NORTHWARD THROUGH THE
MORNING HOURS AS IT SLOWLY MEANDERS NORTHWARD. QPF AND SNOW
AMOUNTS WERE BUMPED UPWARD SUBSTANTIALLY IN THIS BAND THROUGH THE
MORNING HOURS...WITH IMPRESSIVE 20:1 RATIOS NOTED AT THE NWS
OFFICE THIS MORNING. WHILE THESE RATIOS ARE UNLIKELY TO LAST AFTER
SUN UP...IT STILL SEEMS REASONABLE TO ANTICIPATE THAT AT LEAST
10:1 WOULD PERSIST BEYOND SUNRISE.
THE REST OF THE FORECAST STILL LOOKS GOOD FOR TRANSITIONS TO
RAIN/SLEET/FREEZING RAIN IN PORTIONS OF THE AREA. THE DETAILS OF
THE RATIONALE OF THAT PORTION OF THE FORECAST ARE CONTAINED BELOW.
FRIES
PREVIOUS...
A SHORTWAVE MOVING ACROSS OHIO INTO NORTHWESTERN PENNSYLVANIA HAS
ALLOWED FOR A PRECURSOR ROUND OF SNOW IN ADVANCE OF THE MAJOR SYSTEM
ARRIVING THIS MORNING. AN INCH OF SNOW HAS FALLEN AT OUR
OFFICE...AND AREA WEBCAMS SHOW SOME LIGHT ACCUMULATIONS GENERALLY ON
GRASSY SURFACES...ALTHOUGH AREA ROADWAYS STILL APPEAR TO BE MOSTLY
WET. THIS LIGHT SNOW SHOULD CONTINUE THROUGH SUNRISE.
NORTHERN STREAM AND SOUTHERN STREAM SYSTEMS ARE BOTH STARTING THEIR
TREK TO THE EAST...WITH THEIR INTERACTION ABOUT TO AFFECT THE ENTIRE
EAST COAST. SO FAR THE PRECIPITATION SHIELD FROM THE SOUTHERN SYSTEM
IS CONTAINED TO SOUTHERN KENTUCKY AND VIRGINIA...WITH PRECIPITATION
MOVING TO THE NORTHEAST. TRICKIEST PORTION OF THE FORECAST REMAINS
WHAT WILL HAPPEN WITH LOW LEVEL TEMPERATURE PROFILES. ENOUGH WARM
AIR IS EXPECTED TO MOVE IN ALOFT THAT A MIX OF SNOW AND FREEZING
RAIN IS POSSIBLE GENERALLY SOUTH AND EAST OF A LINE FROM ZANESVILLE
TO PITTSBURGH TO DUBOIS DURING THE DAYTIME. IN ADDITION...SURFACE
TEMPERATURES WILL BE CRITICAL...AS PRECIP MAY ACTUALLY FALL AS RAIN
FOR A SEVERAL HOUR PERIOD. LATEST RUNS OF THE RAP STILL SHOW ABOVE
FREEZING TEMPERATURES REACHING ALL THE WAY INTO INDIANA COUNTY NEAR
THE SURFACE. THE RAP CAME IN AS THE WARMEST MODEL FOR SURFACE
TEMPERATURES...BUT IT ALSO USUALLY HANDLES THESE SITUATIONS WELL.
THE HIGHER ELEVATIONS IN THE RIDGES WILL LIKELY HAVE A WINTRY MIX
THROUGH MUCH OF THIS TIME PERIOD WITH AN EXTENDED PERIOD OF FREEZING
RAIN POSSIBLE. NORTH AND WEST OF THE ZZV/PIT/DUJ LINE...SOME SLEET
MAY MIX IN BY THE AFTERNOON...BUT SNOW IS EXPECTED TO BE THE
DOMINANT PRECIPITATION TYPE.
BY EVENING THE TWO SYSTEMS ARE EXPECTED TO BE IN ENOUGH PROXIMITY TO
EACH OTHER TO DEVELOP A COUPLED JET...AND CONSEQUENTLY SHOULD BE THE
TIME PERIOD WHEN THE HIGHEST PRECIPITATION RATES OCCUR. IN THE
RIDGES...FREEZING RAIN WILL CONTINUE THROUGH THE EVENING.
TEMPERATURES WILL LIKELY STILL BE WARM ENOUGH SOUTH AND EAST OF
PITTSBURGH OUTSIDE OF THE HIGHEST ELEVATIONS TO PERSIST WITH RAIN
FOR A FEW HOURS. HOWEVER...WITH ALL SNOW FALLING TO THE WEST OF
PITTSBURGH...SNOW RATES COULD BE QUITE IMPRESSIVE DURING THE EVENING
HOURS FROM ZANESVILLE TO NEW CASTLE AND FRANKLIN. AFTER MIDNIGHT
NEARLY ALL LOCATIONS WILL CHANGEOVER TO SNOW...WITH RATES BEGINNING
TO DIMINISH SLIGHTLY. IF THE WARM LAYER ALOFT PERSISTS...WHICH
LATEST MODELS RUNS HAVE BEEN INDICATING IS POSSIBLE...FREEZING
RAIN MAY HOLD ON FOR A FEW MORE HOURS IN THE RIDGES.
ALTHOUGH ALL LOCATIONS WILL CONTINUE TO RECEIVE SNOW WEDNESDAY
MORNING...THE WIDESPREAD PRECIPITATION SHIELD WILL BE MOVING OFF TO
THE EAST. ALTHOUGH WINDS WILL INITIALLY BE OUT OF THE
NORTH-NORTHWEST...LESS FAVORABLE FOR UPSLOPE/LAKE EFFECT...WINDS
WILL BACK TO THE NORTHWEST BY THE AFTERNOON AND ALLOW THE LAKE
EFFECT MACHINE TO START UP.
ALL IN ALL...ONLY MINOR CHANGES WERE MADE TO THE FORECAST THROUGH
THIS TIME PERIOD. THE AXIS OF HEAVIEST SNOWFALL WAS PUSHED SLIGHTLY
FARTHER TO THE WEST TO ALIGN WITH DEFORMATION ZONE AND THE CHANCES
FOR FREEZING RAIN WERE HELD ONTO LONGER TONIGHT IN THE RIDGES...BUT
OTHERWISE THE INHERITED FORECAST WAS IN GOOD SHAPE. NO CHANGES WERE
NEEDED TO ANY OF THE ADVISORIES OR WARNINGS.
&&
.SHORT TERM /WEDNESDAY NIGHT/...
UPSLOPE AND LAKE EFFECT SNOW WILL CONTINUE WEDNESDAY NIGHT. MODELS
ARE SUGGESTING THAT A DOUBLE LAKE CONNECTION BETWEEN HURON-ERIE IS
POSSIBLE...WHICH COULD RESULT IN SOME LOCALLY HIGHER TOTALS IF A
SINGLE DOMINANT BAND DEVELOP SIMILAR TO WHAT HAPPENED THIS
PREVIOUS SATURDAY. THE RETURN OF WEST-NORTHWESTERLY FLOW WILL
BRING LOWS DOWN INTO THE UPPER TEENS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
DRYING TREND CAN BE ANTICIPATED INTO THE WEEKEND AS THE UPR FLOW
FLATTENS...ALTHOUGH SUB AVG TEMPS WL CONT UNTIL WARM ADVCTN
INTENSIFIES WITH THE ADVN OF LOW PRES EARLY NXT WEEK. PASSAGE OF
THAT TROF IS GFS AND ECMWF FORECAST TO SPREAD RAIN...OR SNOW OVR
THE UPPER OH VALLEY REGION ON MONDAY AND TUESDAY. CHC POPS WERE
THUS INCLUDED FOR THAT TIME FRAME...BUT RESOLUTION OF PCPN TYPE WL
HAVE TO WAIT UNTIL THE SITUATION FURTHER MATURES.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
DETERIORATION TO GENL IFR WL CONT TDA AS LGT SN...THEN A MIXTURE
OF WINTRY PCPN SPREADS OVR THE REGION WITH LOW PRES EMERGING FM
THE GULF COAST AREA. IFR CONDITIONS WL THEN PREVAIL THROUGH TNGT
WITH COLD ADVCNT CHANGING PCPN TO ALL SNOW.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
WDSPRD RSTRNS WL CONT THRU WED NGT AS COLD ADVCTN INTENSIFIES IN
THE WAKE OF EXITING LOW PRES. VFR IS EXPD TO RTN LTR THU WITH BLDG
HIGH PRES AND PERSIST FOR THE RMNDR OF THE WEEK.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL 4 AM EST THURSDAY FOR MDZ001.
OH...WINTER STORM WARNING UNTIL 1 PM EST WEDNESDAY FOR OHZ039>041-
048>050-057-058.
WINTER WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR OHZ059-
068-069.
PA...WINTER STORM WARNING UNTIL 1 PM EST WEDNESDAY FOR PAZ013>016-
020>022.
WINTER WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR PAZ023-
029.
WINTER WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR PAZ031-
073-075.
WINTER STORM WARNING UNTIL 4 AM EST THURSDAY FOR PAZ074-076.
WINTER STORM WARNING FROM NOON TODAY TO 4 AM EST THURSDAY FOR
PAZ007>009.
WV...WINTER STORM WARNING UNTIL 1 PM EST WEDNESDAY FOR WVZ001-002.
WINTER WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR WVZ003-
004.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST
WEDNESDAY FOR WVZ012-021-022.
WINTER WEATHER ADVISORY UNTIL 4 AM EST THURSDAY FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
625 AM EST TUE NOV 26 2013
.SYNOPSIS...
EAST COAST BOUND LOW PRESSURE WILL SPREAD A WINTRY MIX OF
PRECIPITATION OVER THE REGION TODAY. THAT PRECIPITATION WILL
CHANGE TO ALL SNOW TONIGHT.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
ONLY CHANGES FOR THE NR DAWN UPDATE WERE TWEAKS TO HOURLY TRENDS
OF TEMP...PCPN TYPE...AND NR TERM SNOW AMOUNTS OVR AREAS EAST OF PIT.
PREVIOUS...
A SHORTWAVE MOVING ACROSS OHIO INTO NORTHWESTERN PENNSYLVANIA HAS
ALLOWED FOR A PRECURSOR ROUND OF SNOW IN ADVANCE OF THE MAJOR SYSTEM
ARRIVING THIS MORNING. AN INCH OF SNOW HAS FALLEN AT OUR
OFFICE...AND AREA WEBCAMS SHOW SOME LIGHT ACCUMULATIONS GENERALLY ON
GRASSY SURFACES...ALTHOUGH AREA ROADWAYS STILL APPEAR TO BE MOSTLY
WET. THIS LIGHT SNOW SHOULD CONTINUE THROUGH SUNRISE.
NORTHERN STREAM AND SOUTHERN STREAM SYSTEMS ARE BOTH STARTING THEIR
TREK TO THE EAST...WITH THEIR INTERACTION ABOUT TO AFFECT THE ENTIRE
EAST COAST. SO FAR THE PRECIPITATION SHIELD FROM THE SOUTHERN SYSTEM
IS CONTAINED TO SOUTHERN KENTUCKY AND VIRGINIA...WITH PRECIPITATION
MOVING TO THE NORTHEAST. TRICKIEST PORTION OF THE FORECAST REMAINS
WHAT WILL HAPPEN WITH LOW LEVEL TEMPERATURE PROFILES. ENOUGH WARM
AIR IS EXPECTED TO MOVE IN ALOFT THAT A MIX OF SNOW AND FREEZING
RAIN IS POSSIBLE GENERALLY SOUTH AND EAST OF A LINE FROM ZANESVILLE
TO PITTSBURGH TO DUBOIS DURING THE DAYTIME. IN ADDITION...SURFACE
TEMPERATURES WILL BE CRITICAL...AS PRECIP MAY ACTUALLY FALL AS RAIN
FOR A SEVERAL HOUR PERIOD. LATEST RUNS OF THE RAP STILL SHOW ABOVE
FREEZING TEMPERATURES REACHING ALL THE WAY INTO INDIANA COUNTY NEAR
THE SURFACE. THE RAP CAME IN AS THE WARMEST MODEL FOR SURFACE
TEMPERATURES...BUT IT ALSO USUALLY HANDLES THESE SITUATIONS WELL.
THE HIGHER ELEVATIONS IN THE RIDGES WILL LIKELY HAVE A WINTRY MIX
THROUGH MUCH OF THIS TIME PERIOD WITH AN EXTENDED PERIOD OF FREEZING
RAIN POSSIBLE. NORTH AND WEST OF THE ZZV/PIT/DUJ LINE...SOME SLEET
MAY MIX IN BY THE AFTERNOON...BUT SNOW IS EXPECTED TO BE THE
DOMINANT PRECIPITATION TYPE.
BY EVENING THE TWO SYSTEMS ARE EXPECTED TO BE IN ENOUGH PROXIMITY TO
EACH OTHER TO DEVELOP A COUPLED JET...AND CONSEQUENTLY SHOULD BE THE
TIME PERIOD WHEN THE HIGHEST PRECIPITATION RATES OCCUR. IN THE
RIDGES...FREEZING RAIN WILL CONTINUE THROUGH THE EVENING.
TEMPERATURES WILL LIKELY STILL BE WARM ENOUGH SOUTH AND EAST OF
PITTSBURGH OUTSIDE OF THE HIGHEST ELEVATIONS TO PERSIST WITH RAIN
FOR A FEW HOURS. HOWEVER...WITH ALL SNOW FALLING TO THE WEST OF
PITTSBURGH...SNOW RATES COULD BE QUITE IMPRESSIVE DURING THE EVENING
HOURS FROM ZANESVILLE TO NEW CASTLE AND FRANKLIN. AFTER MIDNIGHT
NEARLY ALL LOCATIONS WILL CHANGEOVER TO SNOW...WITH RATES BEGINNING
TO DIMINISH SLIGHTLY. IF THE WARM LAYER ALOFT PERSISTS...WHICH
LATEST MODELS RUNS HAVE BEEN INDICATING IS POSSIBLE...FREEZING
RAIN MAY HOLD ON FOR A FEW MORE HOURS IN THE RIDGES.
ALTHOUGH ALL LOCATIONS WILL CONTINUE TO RECEIVE SNOW WEDNESDAY
MORNING...THE WIDESPREAD PRECIPITATION SHIELD WILL BE MOVING OFF TO
THE EAST. ALTHOUGH WINDS WILL INITIALLY BE OUT OF THE
NORTH-NORTHWEST...LESS FAVORABLE FOR UPSLOPE/LAKE EFFECT...WINDS
WILL BACK TO THE NORTHWEST BY THE AFTERNOON AND ALLOW THE LAKE
EFFECT MACHINE TO START UP.
ALL IN ALL...ONLY MINOR CHANGES WERE MADE TO THE FORECAST THROUGH
THIS TIME PERIOD. THE AXIS OF HEAVIEST SNOWFALL WAS PUSHED SLIGHTLY
FARTHER TO THE WEST TO ALIGN WITH DEFORMATION ZONE AND THE CHANCES
FOR FREEZING RAIN WERE HELD ONTO LONGER TONIGHT IN THE RIDGES...BUT
OTHERWISE THE INHERITED FORECAST WAS IN GOOD SHAPE. NO CHANGES WERE
NEEDED TO ANY OF THE ADVISORIES OR WARNINGS.
&&
.SHORT TERM /WEDNESDAY NIGHT/...
UPSLOPE AND LAKE EFFECT SNOW WILL CONTINUE WEDNESDAY NIGHT. MODELS
ARE SUGGESTING THAT A DOUBLE LAKE CONNECTION BETWEEN HURON-ERIE IS
POSSIBLE...WHICH COULD RESULT IN SOME LOCALLY HIGHER TOTALS IF A
SINGLE DOMINANT BAND DEVELOP SIMILAR TO WHAT HAPPENED THIS
PREVIOUS SATURDAY. THE RETURN OF WEST-NORTHWESTERLY FLOW WILL
BRING LOWS DOWN INTO THE UPPER TEENS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
DRYING TREND CAN BE ANTICIPATED INTO THE WEEKEND AS THE UPR FLOW
FLATTENS...ALTHOUGH SUB AVG TEMPS WL CONT UNTIL WARM ADVCTN
INTENSIFIES WITH THE ADVN OF LOW PRES EARLY NXT WEEK. PASSAGE OF
THAT TROF IS GFS AND ECMWF FORECAST TO SPREAD RAIN...OR SNOW OVR
THE UPPER OH VALLEY REGION ON MONDAY AND TUESDAY. CHC POPS WERE
THUS INCLUDED FOR THAT TIME FRAME...BUT RESOLUTION OF PCPN TYPE WL
HAVE TO WAIT UNTIL THE SITUATION FURTHER MATURES.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
DETERIORATION TO GENL IFR WL CONT TDA AS LGT SN...THEN A MIXTURE
OF WINTRY PCPN SPREADS OVR THE REGION WITH LOW PRES EMERGING FM
THE GULF COAST AREA. IFR CONDITIONS WL THEN PREVAIL THROUGH TNGT
WITH COLD ADVCNT CHANGING PCPN TO ALL SNOW.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
WDSPRD RSTRNS WL CONT THRU WED NGT AS COLD ADVCTN INTENSIFIES IN
THE WAKE OF EXITING LOW PRES. VFR IS EXPD TO RTN LTR THU WITH BLDG
HIGH PRES AND PERSIST FOR THE RMNDR OF THE WEEK.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL 4 AM EST THURSDAY FOR MDZ001.
OH...WINTER STORM WARNING FROM 10 AM THIS MORNING TO 1 PM EST
WEDNESDAY FOR OHZ039>041-048>050-057-058.
WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 1 PM EST
WEDNESDAY FOR OHZ059-068-069.
PA...WINTER STORM WARNING FROM 10 AM THIS MORNING TO 1 PM EST
WEDNESDAY FOR PAZ013>016-020>022.
WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 1 PM EST
WEDNESDAY FOR PAZ023-029.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST
WEDNESDAY FOR PAZ031-073-075.
WINTER STORM WARNING UNTIL 4 AM EST THURSDAY FOR PAZ074-076.
WINTER STORM WARNING FROM NOON TODAY TO 4 AM EST THURSDAY FOR
PAZ007>009.
WV...WINTER STORM WARNING FROM 10 AM THIS MORNING TO 1 PM EST
WEDNESDAY FOR WVZ001-002.
WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 1 PM EST
WEDNESDAY FOR WVZ003-004.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST
WEDNESDAY FOR WVZ012-021-022.
WINTER WEATHER ADVISORY UNTIL 4 AM EST THURSDAY FOR WVZ023-041.
&&
$$
15
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
328 AM EST TUE NOV 26 2013
.SYNOPSIS...
AS LOW PRESSURE MOVES UP THE EAST COAST...A WINTRY MIX WILL ENTER
THE REGION BEFORE CHANGING TO ALL SNOW AFTER MIDNIGHT. SNOW WILL
DIMINISH WEDNESDAY INTO THURSDAY...WITH DRY WEATHER UNTIL AT LEAST
SUNDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
A SHORTWAVE MOVING ACROSS OHIO INTO NORTHWESTERN PENNSYLVANIA HAS
ALLOWED FOR A PRECURSOR ROUND OF SNOW IN ADVANCE OF THE MAJOR SYSTEM
ARRIVING THIS MORNING. AN INCH OF SNOW HAS FALLEN AT OUR
OFFICE...AND AREA WEBCAMS SHOW SOME LIGHT ACCUMULATIONS GENERALLY ON
GRASSY SURFACES...ALTHOUGH AREA ROADWAYS STILL APPEAR TO BE MOSTLY
WET. THIS LIGHT SNOW SHOULD CONTINUE THROUGH SUNRISE.
NORTHERN STREAM AND SOUTHERN STREAM SYSTEMS ARE BOTH STARTING THEIR
TREK TO THE EAST...WITH THEIR INTERACTION ABOUT TO AFFECT THE ENTIRE
EAST COAST. SO FAR THE PRECIPITATION SHIELD FROM THE SOUTHERN SYSTEM
IS CONTAINED TO SOUTHERN KENTUCKY AND VIRGINIA...WITH PRECIPITATION
MOVING TO THE NORTHEAST. TRICKIEST PORTION OF THE FORECAST REMAINS
WHAT WILL HAPPEN WITH LOW LEVEL TEMPERATURE PROFILES. ENOUGH WARM
AIR IS EXPECTED TO MOVE IN ALOFT THAT A MIX OF SNOW AND FREEZING
RAIN IS POSSIBLE GENERALLY SOUTH AND EAST OF A LINE FROM ZANESVILLE
TO PITTSBURGH TO DUBOIS DURING THE DAYTIME. IN ADDITION...SURFACE
TEMPERATURES WILL BE CRITICAL...AS PRECIP MAY ACTUALLY FALL AS RAIN
FOR A SEVERAL HOUR PERIOD. LATEST RUNS OF THE RAP STILL SHOW ABOVE
FREEZING TEMPERATURES REACHING ALL THE WAY INTO INDIANA COUNTY NEAR
THE SURFACE. THE RAP CAME IN AS THE WARMEST MODEL FOR SURFACE
TEMPERATURES...BUT IT ALSO USUALLY HANDLES THESE SITUATIONS WELL.
THE HIGHER ELEVATIONS IN THE RIDGES WILL LIKELY HAVE A WINTRY MIX
THROUGH MUCH OF THIS TIME PERIOD WITH AN EXTENDED PERIOD OF FREEZING
RAIN POSSIBLE. NORTH AND WEST OF THE ZZV/PIT/DUJ LINE...SOME SLEET
MAY MIX IN BY THE AFTERNOON...BUT SNOW IS EXPECTED TO BE THE
DOMINANT PRECIPITATION TYPE.
BY EVENING THE TWO SYSTEMS ARE EXPECTED TO BE IN ENOUGH PROXIMITY TO
EACH OTHER TO DEVELOP A COUPLED JET...AND CONSEQUENTLY SHOULD BE THE
TIME PERIOD WHEN THE HIGHEST PRECIPITATION RATES OCCUR. IN THE
RIDGES...FREEZING RAIN WILL CONTINUE THROUGH THE EVENING.
TEMPERATURES WILL LIKELY STILL BE WARM ENOUGH SOUTH AND EAST OF
PITTSBURGH OUTSIDE OF THE HIGHEST ELEVATIONS TO PERSIST WITH RAIN
FOR A FEW HOURS. HOWEVER...WITH ALL SNOW FALLING TO THE WEST OF
PITTSBURGH...SNOW RATES COULD BE QUITE IMPRESSIVE DURING THE EVENING
HOURS FROM ZANESVILLE TO NEW CASTLE AND FRANKLIN. AFTER MIDNIGHT
NEARLY ALL LOCATIONS WILL CHANGEOVER TO SNOW...WITH RATES BEGINNING
TO DIMINISH SLIGHTLY. IF THE WARM LAYER ALOFT PERSISTS...WHICH
LATEST MODELS RUNS HAVE BEEN INDICATING IS POSSIBLE...FREEZING
RAIN MAY HOLD ON FOR A FEW MORE HOURS IN THE RIDGES.
ALTHOUGH ALL LOCATIONS WILL CONTINUE TO RECEIVE SNOW WEDNESDAY
MORNING...THE WIDESPREAD PRECIPITATION SHIELD WILL BE MOVING OFF TO
THE EAST. ALTHOUGH WINDS WILL INITIALLY BE OUT OF THE
NORTH-NORTHWEST...LESS FAVORABLE FOR UPSLOPE/LAKE EFFECT...WINDS
WILL BACK TO THE NORTHWEST BY THE AFTERNOON AND ALLOW THE LAKE
EFFECT MACHINE TO START UP.
ALL IN ALL...ONLY MINOR CHANGES WERE MADE TO THE FORECAST THROUGH
THIS TIME PERIOD. THE AXIS OF HEAVIEST SNOWFALL WAS PUSHED SLIGHTLY
FARTHER TO THE WEST TO ALIGN WITH DEFORMATION ZONE AND THE CHANCES
FOR FREEZING RAIN WERE HELD ONTO LONGER TONIGHT IN THE RIDGES...BUT
OTHERWISE THE INHERITED FORECAST WAS IN GOOD SHAPE. NO CHANGES WERE
NEEDED TO ANY OF THE ADVISORIES OR WARNINGS.
&&
.SHORT TERM /WEDNESDAY NIGHT/...
UPSLOPE AND LAKE EFFECT SNOW WILL CONTINUE WEDNESDAY NIGHT. MODELS
ARE SUGGESTING THAT A DOUBLE LAKE CONNECTION BETWEEN HURON-ERIE IS
POSSIBLE...WHICH COULD RESULT IN SOME LOCALLY HIGHER TOTALS IF A
SINGLE DOMINANT BAND DEVELOP SIMILAR TO WHAT HAPPENED THIS
PREVIOUS SATURDAY. THE RETURN OF WEST-NORTHWESTERLY FLOW WILL
BRING LOWS DOWN INTO THE UPPER TEENS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
DRYING TREND CAN BE ANTICIPATED INTO THE WEEKEND AS THE UPR FLOW
FLATTENS...ALTHOUGH SUB AVG TEMPS WL CONT UNTIL WARM ADVCTN
INTENSIFIES WITH THE ADVN OF LOW PRES EARLY NXT WEEK. PASSAGE OF
THAT TROF IS GFS AND ECMWF FORECAST TO SPREAD RAIN...OR SNOW OVR
THE UPPER OH VALLEY REGION ON MONDAY AND TUESDAY. CHC POPS WERE
THUS INCLUDED FOR THAT TIME FRAME...BUT RESOLUTION OF PCPN TYPE WL
HAVE TO WAIT UNTIL THE SITUATION FURTHER MATURES.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
GRADUAL DETERIORATION TO GENL IFR CAN BE EXPECTED TODAY AS LGT
SN...THEN A MIXTURE OF WINTRY PCPN SPREADS OVR THE REGION AS LOW
PRES EMERGES FM THE GULF COAST AREA. IFR CONDITIONS WL THEN
PREVAIL THROUGH TNGT WITH COLD ADVCNT CHANGING PCPN TO ALL SNOW.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
WDSPRD RSTRNS WL CONT THRU WED NGT AS COLD ADVCTN INTENSIFIES IN
THE WAKE OF EXITING LOW PRES. VFR IS EXPD TO RTN LTR THU WITH BLDG
HIGH PRES AND PERSIST FOR THE RMNDR OF THE WEEK.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING FROM 7 AM THIS MORNING TO 4 AM EST
THURSDAY FOR MDZ001.
OH...WINTER STORM WARNING FROM 10 AM THIS MORNING TO 1 PM EST
WEDNESDAY FOR OHZ039>041-048>050-057-058.
WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 1 PM EST
WEDNESDAY FOR OHZ059-068-069.
PA...WINTER STORM WARNING FROM 10 AM THIS MORNING TO 1 PM EST
WEDNESDAY FOR PAZ013>016-020>022.
WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 1 PM EST
WEDNESDAY FOR PAZ023-029.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST
WEDNESDAY FOR PAZ031-073-075.
WINTER STORM WARNING FROM 7 AM THIS MORNING TO 4 AM EST
THURSDAY FOR PAZ074-076.
WINTER STORM WARNING FROM NOON TODAY TO 4 AM EST THURSDAY FOR
PAZ007>009.
WV...WINTER STORM WARNING FROM 10 AM THIS MORNING TO 1 PM EST
WEDNESDAY FOR WVZ001-002.
WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 1 PM EST
WEDNESDAY FOR WVZ003-004.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST
WEDNESDAY FOR WVZ012-021-022.
WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 4 AM EST
THURSDAY FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
506 PM EST TUE NOV 26 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 505 PM EST TUE NOV 26 2013
WV IMAGERY AND RUC ANALYSIS REVEALS A WELL-DEFINED MID/UPPER LEVEL
SHORTWAVE ROTATING EAST ACROSS THE UPPER GREAT LAKES THIS AFTERNOON.
AT THE SFC...LOW PRES WAS LOCATED OVER NRN LAKE HURON WITH A COLD
FRONT EXTENDING SE THROUGH LOWER MI AND A TROUGH STRETCHING TO THE
NORTHWEST OVER NRN ONTARIO. 700-300 QVECTOR CONV OUT AHEAD
OF THE SHRTWV SUPPORTED AN AREA OF SHSN ACROSS WEST AND CNTRL UPPER
MI EARLIER TODAY WITH SOME HEAVIER LES REPORTED ALONG AND BEHIND
INITIAL FRONTAL PASSAGE. SOME AREAS NEAR WAKEFIELD/BESSEMER REPORTED
8-9 INCHES OF LAKE ENHANCED SNOW ALREADY FROM THE SNOW THAT STARTED
EARLY THIS MORNING WHILE MODERATE TO HEAVY LES WAS ALSO REPORTED
OVER PORTIONS OF HOUGHTON...NW MQT AND WRN ALGER COUNTIES.
EXPECT LES TO CONTINUE MODERATE TO HEAVY AT TIMES TONIGHT INTO
WEDNESDAY AS THE TROUGH JUST NORTH OF LAKE SUPERIOR MOVES SOUTH
ACROSS THE AREA LATE THIS EVENING AND SHIFTS WINDS FROM NW TO MORE
NNE DIRECTION OVER LAKE SUPERIOR. THIS WILL PUSH HEAVIER LES BANDS
INTO MARQUETTE COUNTY AND WRN ALGER COUNTY WITH ANOTHER DOMINANT
BAND LIKELY SETTING UP OVER THE PORCUPINE MTNS/IRONWOOD AREA. MOST
OF THE MODELS SUGGEST THAT THIS WILL OCCUR JUST AFT 00Z WHEN THE MID
LEVEL TROUGH AXIS MOVES INTO ERN UPPER MI. EXPECT THE GREATEST
SNOWFALL RATES NEAR MARQUETTE LATE THIS EVENING SHIFTING INTO THE
HIGHER TERRAIN WEST OF MARQUETTE OVERNIGHT INTO WEDNESDAY AS THE
UPSLOPE COMPONENT STRENGTHENS. OVER THE WEST...THE STRONGEST LOW
LEVEL CONV IS EXPECTED INTO IRONWOOD/WAKEFIELD/BERGLAND/PORCUPINE
MTNS WITH SNOWBANDS ORIGINATING NEAR THUNDER BAY AND PERHAPS
CONNECTING WITH LAKE NIPIGON IN STRONG MOIST CYCLONIC NNE FLOW. WITH
BUFR SNDGS INDICATING THE STRONGER UPWARD MOTION IN THE DGZ FOR MUCH
OF THE EVENT...EXPECT SLR VALUES IN THE 25/1 RANGE ARE EXPECTED.
THERE MAY ALSO BE SOME GUSTY WINDS ALONG THE LAKESHORE TONIGHT WHERE
WINDS MAY GUST TO AROUND 30 MPH. THE SNOW AND BLOWING SNOW WILL MAKE
ROADS HAZARDOUS AND TRAVEL DIFFICULT TONIGHT INTO WEDNESDAY.
THE GREATEST SNOWFALL AMOUNTS TONIGHT SHOULD ALSO BE IN THE 3 TO 7
INCH RANGE OVER THE HIGHER TERRAIN OF WRN MQT COUNTY AND FROM WHITE
PINE TO BERGLAND WEST TO IRONWOOD. WEDNESDAY....EXPECT ANOTHER 2-4
OF SNOW OVER GOGEBIC-ONTONAGON COUNTIES WITH ANOTHER 3-6 INCHES OVER
THE HIGHER TERRAIN OF WRN MQT COUNTY. GIVEN EXPECTED AMOUNTS AND
BLOWING SNOW POTENTIAL HAVE DECIDED TO UPGRADE GOGEBIC-ONTONAGON TO
AN LES WARNING THROUGH 18Z WED WHILE I ALSO UPGRADED MQT TO LES
WARNING FOR TONIGHT THROUGH WEDNESDAY.
FOR NOW LEFT LES ADVISORIES GOING FOR KEWEENAW-NRN HOUGHTON INTO
TONIGHT AND FOR BARAGA COUNTIES AND ALGER COUNITES INTO WED
AFTERNOON. WRN ALGER WILL NEED TO BE CLOSELY MONITORED TONIGHT AS
HEAVIER LES BANDS COULD PUSH AMOUNTS NEAR WARNING CRITERIA.
INFLUZ OF DRIER AIR AND WEAKENING NNE FLOW SHOULD ALLOW LES TO TAPER
OFF WED AFTERNOON FROM WEST TO EAST.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 416 PM EST TUE NOV 26 2013
UPPER MICHIGAN WILL REMAIN UNDER THE INFLUENCE OF THE MAIN LOW NEAR
HUDSON BAY THROUGH EARLY FRIDAY...WITH DISTURBANCES CONTINUING TO
SWING ACROSS THE REGION. THE THERMOMETERS OUTSIDE WILL BE BELOW
TURKEY THAWING CONDITIONS...BOTTOMING OUT IN THE TEENS FOR MOST
LOCATIONS.
THOSE WHO ENJOY SNOW WILL BE THANKFUL FOR MORE SNOW SHOWERS
THURSDAY. THE SFC LOW ACROSS SD AT 00Z THURSDAY WILL WEAKEN OVER MN
AND IA WEDNESDAY NIGHT...BEFORE SLOWLY CROSSING UPPER MI AND LAKE MI
THURSDAY INTO FRIDAY. CURRENT THINKING IS FOR THE BEST BANDS OF SNOW
TO BE OFF-SHORE OVER W LAKE SUPERIOR...STRETCHING THROUGH KEWEENAW
COUNTY AND TROUGH S CENTRAL LAKE SUPERIOR. COULD HAVE 2-5IN OF LAKE
EFFECT SNOW FOR KEWEENAW COUNTY. THE NAM AND OTHER SMALLER SCALE
MODELS ARE A LITTLE MORE BULLISH ON THE SNOW/QPF ACCUMULATION OVER
THE TIP OF THE KEWEENAW PENINSULA. MAY NEED AN ADVISORY IF CURRENT
THINKING REMAINS.
OTHERWISE...FRIDAY WILL BE MARKED BY WAA. LEFTOVER POCKETS OF COLD
AIR FRIDAY WILL KEEP TEMPERATURES MAXING OUT IN THE MID TO UPPER
20S. 850MB TEMPS SHOULD RISE INTO THE -7 TO -13C RANGE BY 00Z
SATURDAY. THE 500MB RIDGE BUILDING IN FRIDAY AFTERNOON AND EVENING
WILL BE SHORT LIVED. THE NEXT TROUGH SET UP FROM MANITOBA THROUGH
THE N PLAINS AT 06Z SATURDAY SHOULD SLOWLY EDGE ACROSS MANITOBA AND
THE UPPER GREAT LAKES SATURDAY THROUGH EARLY SUNDAY. WHILE POPS WILL
INCREASE BACK TO CHANCES AGAIN SATURDAY INTO SATURDAY NIGHT THERE
LOOKS TO BE LITTLE MOISTURE TO WORK WITH...GIVEN THE ORIGIN OF THE
DISTURBANCE.
EXPECT BREEZY CONDITIONS E ON SATURDAY...WITH WINDS JUST ABOVE THE
SFC OUT OF THE SSW AROUND 40-45KTS. SFC TEMPS SHOULD RETURN TO THE
30S CWA WIDE FOR THE 1ST TIME SINCE MONDAY. THE NEXT CLIPPER-LIKE
SYSTEM SHOULD BE SWINGING IN FROM THE NW SATURDAY AFTERNOON. TIMING
IS STILL A CONCERN...WITH THE 12Z RUNS OF THE ECMWF AND GFS
DIFFERING BY 350MI AT 18Z SATURDAY. THE ECMWF HAS IT ACROSS S
CENTRAL ONTARIO...WHILE THE LOW OFF THE GFS IS NEAR THE
MANITOBA/ONTARIO BORDER. OF MORE OF A CONCERN IS THEIR HANDLING OF
THE NEXT...MORE SIGNIFICANT LOOKING SYSTEM...IN THE FORM OF A 500MB
LOW SINKING ACROSS THE PACIFIC NW MONDAY. STILL...THE IMPACTS OF
THAT ONE WILL NOT REALLY BE NOTICED UNTIL CLOSER TO MID WEEK...WITH
THE ASSOCIATED SFC LOW PUSHING ACROSS THE PLAINS STATES TUESDAY AS
THE 500MB LOW SLIDES ACROSS MT. WILL HAVE TO WAIT TO SEE WHAT SORT
OF IMPACTS THIS ONE WILL HAVE ACROSS THE UPPER GREAT LAKES OVER THE
NEXT FEW DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1242 PM EST TUE NOV 26 2013
KCMX...EXPECT IFR CONDITIONS THROUGH MUCH OF THE PERIOD IN LAKE
EFFECT SNOW AND SOME BLOWING OF SNOW DUE TO WINDS GUSTING NEAR 25
MPH. WINDS WILL SHIFT FROM NW TO N LATER THIS EVENING CONTINUING INTO
WEDNESDAY.
KIWD...EXPECT MVFR CONDITIONS TO OCCASIONAL IFR CONDITIONS TODAY IN
NW FLOW LAKE EFFECT. CONDITIONS WILL DETERIORATE TO LIFR LATER THIS
EVENING AS WINDS SHIFT NORTHERLY AND LAKE EFFECT SNOW INCREASES.
KSAW....MVFR CONDITIONS IN SCT LAKE EFFECT SNOW WILL DETERIORATE TO
IFR AND PERHAPS EVEN OCCASIONALLY LIFR LATE TONIGHT INTO WEDNESDAY AS
WINDS SHIFT FROM NW TO N AS LAKE EFFECT SNOW INCREASES IN INTENSITY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 416 PM EST TUE NOV 26 2013
WEAK LOW PRESSURE OVER S ONTARIO WILL MOVE E OVERNIGHT AS HIGH
PRESSURE OVER THE N PLAINS TONIGHT SLIDES INTO THE GREAT LAKES
REGION...WEAKENING SLIGHTLY BY WEDNESDAY AFTERNOON. IN BETWEEN THESE
2 SYSTEMS...N GALES TO 35KTS ARE EXPECTED OVER MAINLY CENTRAL AND E
LAKE SUPERIOR TONIGHT...CONTINUING WITH MAINLY GALE FORCE GUSTS
WEDNESDAY OVER E PORTIONS OF LAKE SUPERIOR.
LOW PRESSURE OVER THE SE U.S. TONIGHT WILL MOVE NORTHEASTWARD INTO
THE NEW ENGLAND STATES BY WEDNESDAY EVENING WHILE DEEPENING...WHICH
WILL KEEP A TROUGH OVER THE LOWER LAKES. FOR THURSDAY INTO
FRIDAY...ANOTHER WEAK TROUGH SHOULD CROSS LAKE SUPERIOR...MERGING
WITH A HIGH OVER LAKE ONTARIO BY FRIDAY EVENING. AS THE HIGH MOVES E
TOWARDS THE ATLANTIC SATURDAY AFTERNOON INTO SUNDAY...ANOTHER WEAK
TROUGH WILL CROSS LAKE SUPERIOR. ANOTHER PERIOD OF STRONGER
WINDS...OUT OF THE S NEAR 30KTS...WILL BE POSSIBLE SATURDAY OVER
MAINLY E LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 1 PM EST /NOON CST/ WEDNESDAY FOR
MIZ002-009.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001-
003.
LAKE EFFECT SNOW ADVISORY UNTIL 3 PM EST WEDNESDAY FOR MIZ004-
006.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST WEDNESDAY FOR MIZ005.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ084.
LAKE SUPERIOR...
GALE WARNING FROM MIDNIGHT TONIGHT TO 1 PM EST WEDNESDAY FOR
LSZ266-267.
GALE WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST WEDNESDAY FOR
LSZ265.
GALE WARNING FROM MIDNIGHT TONIGHT TO 5 AM EST WEDNESDAY FOR
LSZ264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...VOSS
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
417 PM EST TUE NOV 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EST TUE NOV 26 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A WELL DEFINED UPSTREAM
MID/UPPER LEVEL LOW/SHORTWAVE TROUGH FROM NW OF LAKE SUPERIOR INTO
NW MN. AT THE SFC...LOW PRES WAS LOCATED NE OF LAKE SUPERIOR(NEAR
WAWA ONTARIO) WITH A COLD FRONT EXTENDING THROUGH WHITEFISH BAY INTO
NW LOWER MI AND A TROUGH STRETCHING TO THE WEST. 700-300 QVECTOR
CONV AHEAD OF THE SHRTWV SUPPORTED SCT -SHSN/FLURRIES FROM NE MN
INTO CNTRL UPPER MI. RADAR ALSO INDICATED AN INCREASE IN LES FROM
FROM NEAR BIG BAY EASTWARD ALIGNED WITH 280-290 LOW LEVEL FLOW.
HOWEVER...WEBCAMS AND SFC OBS OVER WRN UPPER MI DID NOT SHOW A
SIGNFICANT INCREASE IN SNOW INTENSITY OVERNIGHT.
TODAY...EXPECT LES TO INCREASE THIS MORNING OVER THE WEST AS THE MID
LEVEL LOW SLIDES TO THE SOUTHEAST WITH 850/700 MB TEMPS DROPPING TO
-17C/-25C...INCREASING 850-700 MOISTURE AND CLIMBING INVERSION
HEIGHTS. THE HIGHER RES MODELS SUGGEST THAT THE MOST FAVORABLE LOW
LEVEL CONV AND HIGHER LES POTENTIAL IN THE VEERING WIND PATTERN WILL
SET UP BETWEEN TWIN LAKES AND IRONWOOD BEFORE WINDS BEOMCE MORE NNW
LATER IN THE AFTERNOON. HIGHER TERRAIN LOCATIONS SHOULD SEE SNOW
AMOUNTS IN THE 3 TO 6 INCH RANGE WITH SOME LOCALLY HIGHER AMOUNTS
POSSIBLE. OVER THE EAST...THE WNW FLOW SHOULD CONFINE THE STRONGER
LES BANDS TO AREAS NEAR THE LAKE EAST OF MUNISING.
TONIGHT...THERE IS STILL UNCERTAINTY WITH HOW QUICKLY WINDS WILL
VEER OVER THE CNTRL AND EAST WHICH WILL PUSH THE STRONGER LES BANDS
INTO MARQUETTE COUNTY AND WRN ALGER COUNTY. MOST OF THE MODELS SUGGEST
THAT THIS WILL OCCUR AT OR LATER THAN 00Z WHEN THE MID LEVEL TROUGH
AXIS MOVES INTO ERN UPPER MI. THE NNW WINDS ARE EXPECTED TO GRADUALLY
VEER TO THE NNE TONIGHT. SO...THE GREATEST SNOWFALL RATES NEAR
MARQUETTE ARE EXPECTED LATE THIS EVENING AND THEN WILL SHIFT INTO THE
HIGHER TERRAIN TO THE WEST AS THE UPSLOPE COMPONENT STRENGTHENS. OVER
THE WEST...THE STRONGEST LOW LEVEL CONV IS EXPECTED INTO
IRONWOOD/WAKEFIELD/BERGLANDWITH SNOWBANDS ORIGINATING NEAR THUNDER
BAY. THE GREATEST SNOWFALL AMOUNTS TONIGHT SHOULD ALSO BE IN THE 3 TO
6 INCH RANGE.
WITH THE STRONGER UPWARD MOTION IN THE DGZ FOR MUCH OF THE
EVENT...SLR VALUES IN THE 20-25/1 RANGE ARE EXPECTED. THERE MAY ALSO
BE SOME GUSTY WINDS ALONG THE LAKESHORE TONIGHT WHERE WINDS MAY GUST
TO AROUND 30 MPH. ALTHOUGH THE SNOW MAY SLOW TRAVEL AND MAKE ROADS
HAZARDOUS BUT OVERALL IMPACTS ARE NOT EXPECTED TO BE SEVERE.
SO...GOING LES ADVISORY LEVEL HEADLINES FOR THE NORTHERN CWA IS ON
TRACK.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 416 PM EST TUE NOV 26 2013
UPPER MICHIGAN WILL REMAIN UNDER THE INFLUENCE OF THE MAIN LOW NEAR
HUDSON BAY THROUGH EARLY FRIDAY...WITH DISTURBANCES CONTINUING TO
SWING ACROSS THE REGION. THE THERMOMETERS OUTSIDE WILL BE BELOW
TURKEY THAWING CONDITIONS...BOTTOMING OUT IN THE TEENS FOR MOST
LOCATIONS.
THOSE WHO ENJOY SNOW WILL BE THANKFUL FOR MORE SNOW SHOWERS
THURSDAY. THE SFC LOW ACROSS SD AT 00Z THURSDAY WILL WEAKEN OVER MN
AND IA WEDNESDAY NIGHT...BEFORE SLOWLY CROSSING UPPER MI AND LAKE MI
THURSDAY INTO FRIDAY. CURRENT THINKING IS FOR THE BEST BANDS OF SNOW
TO BE OFF-SHORE OVER W LAKE SUPERIOR...STRETCHING THROUGH KEWEENAW
COUNTY AND TROUGH S CENTRAL LAKE SUPERIOR. COULD HAVE 2-5IN OF LAKE
EFFECT SNOW FOR KEWEENAW COUNTY. THE NAM AND OTHER SMALLER SCALE
MODELS ARE A LITTLE MORE BULLISH ON THE SNOW/QPF ACCUMULATION OVER
THE TIP OF THE KEWEENAW PENINSULA. MAY NEED AN ADVISORY IF CURRENT
THINKING REMAINS.
OTHERWISE...FRIDAY WILL BE MARKED BY WAA. LEFTOVER POCKETS OF COLD
AIR FRIDAY WILL KEEP TEMPERATURES MAXING OUT IN THE MID TO UPPER
20S. 850MB TEMPS SHOULD RISE INTO THE -7 TO -13C RANGE BY 00Z
SATURDAY. THE 500MB RIDGE BUILDING IN FRIDAY AFTERNOON AND EVENING
WILL BE SHORT LIVED. THE NEXT TROUGH SET UP FROM MANITOBA THROUGH
THE N PLAINS AT 06Z SATURDAY SHOULD SLOWLY EDGE ACROSS MANITOBA AND
THE UPPER GREAT LAKES SATURDAY THROUGH EARLY SUNDAY. WHILE POPS WILL
INCREASE BACK TO CHANCES AGAIN SATURDAY INTO SATURDAY NIGHT THERE
LOOKS TO BE LITTLE MOISTURE TO WORK WITH...GIVEN THE ORIGIN OF THE
DISTURBANCE.
EXPECT BREEZY CONDITIONS E ON SATURDAY...WITH WINDS JUST ABOVE THE
SFC OUT OF THE SSW AROUND 40-45KTS. SFC TEMPS SHOULD RETURN TO THE
30S CWA WIDE FOR THE 1ST TIME SINCE MONDAY. THE NEXT CLIPPER-LIKE
SYSTEM SHOULD BE SWINGING IN FROM THE NW SATURDAY AFTERNOON. TIMING
IS STILL A CONCERN...WITH THE 12Z RUNS OF THE ECMWF AND GFS
DIFFERING BY 350MI AT 18Z SATURDAY. THE ECMWF HAS IT ACROSS S
CENTRAL ONTARIO...WHILE THE LOW OFF THE GFS IS NEAR THE
MANITOBA/ONTARIO BORDER. OF MORE OF A CONCERN IS THEIR HANDLING OF
THE NEXT...MORE SIGNIFICANT LOOKING SYSTEM...IN THE FORM OF A 500MB
LOW SINKING ACROSS THE PACIFIC NW MONDAY. STILL...THE IMPACTS OF
THAT ONE WILL NOT REALLY BE NOTICED UNTIL CLOSER TO MID WEEK...WITH
THE ASSOCIATED SFC LOW PUSHING ACROSS THE PLAINS STATES TUESDAY AS
THE 500MB LOW SLIDES ACROSS MT. WILL HAVE TO WAIT TO SEE WHAT SORT
OF IMPACTS THIS ONE WILL HAVE ACROSS THE UPPER GREAT LAKES OVER THE
NEXT FEW DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1242 PM EST TUE NOV 26 2013
KCMX...EXPECT IFR CONDITIONS THROUGH MUCH OF THE PERIOD IN LAKE
EFFECT SNOW AND SOME BLOWING OF SNOW DUE TO WINDS GUSTING NEAR 25
MPH. WINDS WILL SHIFT FROM NW TO N LATER THIS EVENING CONTINUING INTO
WEDNESDAY.
KIWD...EXPECT MVFR CONDITIONS TO OCCASIONAL IFR CONDITIONS TODAY IN
NW FLOW LAKE EFFECT. CONDITIONS WILL DETERIORATE TO LIFR LATER THIS
EVENING AS WINDS SHIFT NORTHERLY AND LAKE EFFECT SNOW INCREASES.
KSAW....MVFR CONDITIONS IN SCT LAKE EFFECT SNOW WILL DETERIORATE TO
IFR AND PERHAPS EVEN OCCASIONALLY LIFR LATE TONIGHT INTO WEDNESDAY AS
WINDS SHIFT FROM NW TO N AS LAKE EFFECT SNOW INCREASES IN INTENSITY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 416 PM EST TUE NOV 26 2013
WEAK LOW PRESSURE OVER S ONTARIO WILL MOVE E OVERNIGHT AS HIGH
PRESSURE OVER THE N PLAINS TONIGHT SLIDES INTO THE GREAT LAKES
REGION...WEAKENING SLIGHTLY BY WEDNESDAY AFTERNOON. IN BETWEEN THESE
2 SYSTEMS...N GALES TO 35KTS ARE EXPECTED OVER MAINLY CENTRAL AND E
LAKE SUPERIOR TONIGHT...CONTINUING WITH MAINLY GALE FORCE GUSTS
WEDNESDAY OVER E PORTIONS OF LAKE SUPERIOR.
LOW PRESSURE OVER THE SE U.S. TONIGHT WILL MOVE NORTHEASTWARD INTO
THE NEW ENGLAND STATES BY WEDNESDAY EVENING WHILE DEEPENING...WHICH
WILL KEEP A TROUGH OVER THE LOWER LAKES. FOR THURSDAY INTO
FRIDAY...ANOTHER WEAK TROUGH SHOULD CROSS LAKE SUPERIOR...MERGING
WITH A HIGH OVER LAKE ONTARIO BY FRIDAY EVENING. AS THE HIGH MOVES E
TOWARDS THE ATLANTIC SATURDAY AFTERNOON INTO SUNDAY...ANOTHER WEAK
TROUGH WILL CROSS LAKE SUPERIOR. ANOTHER PERIOD OF STRONGER
WINDS...OUT OF THE S NEAR 30KTS...WILL BE POSSIBLE SATURDAY OVER
MAINLY E LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 1 PM EST /NOON CST/ WEDNESDAY FOR
MIZ002-009.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001-
003.
LAKE EFFECT SNOW ADVISORY UNTIL 3 PM EST WEDNESDAY FOR MIZ004-
006.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST WEDNESDAY FOR MIZ005.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ084.
LAKE SUPERIOR...
GALE WARNING FROM MIDNIGHT TONIGHT TO 1 PM EST WEDNESDAY FOR
LSZ266-267.
GALE WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST WEDNESDAY FOR
LSZ265.
GALE WARNING FROM MIDNIGHT TONIGHT TO 5 AM EST WEDNESDAY FOR
LSZ264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...VOSS
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
108 PM EST TUE NOV 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EST TUE NOV 26 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A WELL DEFINED UPSTREAM
MID/UPPER LEVEL LOW/SHORTWAVE TROUGH FROM NW OF LAKE SUPERIOR INTO
NW MN. AT THE SFC...LOW PRES WAS LOCATED NE OF LAKE SUPERIOR(NEAR
WAWA ONTARIO) WITH A COLD FRONT EXTENDING THROUGH WHITEFISH BAY INTO
NW LOWER MI AND A TROUGH STRETCHING TO THE WEST. 700-300 QVECTOR
CONV AHEAD OF THE SHRTWV SUPPORTED SCT -SHSN/FLURRIES FROM NE MN
INTO CNTRL UPPER MI. RADAR ALSO INDICATED AN INCREASE IN LES FROM
FROM NEAR BIG BAY EASTWARD ALIGNED WITH 280-290 LOW LEVEL FLOW.
HOWEVER...WEBCAMS AND SFC OBS OVER WRN UPPER MI DID NOT SHOW A
SIGNFICANT INCREASE IN SNOW INTENSITY OVERNIGHT.
TODAY...EXPECT LES TO INCREASE THIS MORNING OVER THE WEST AS THE MID
LEVEL LOW SLIDES TO THE SOUTHEAST WITH 850/700 MB TEMPS DROPPING TO
-17C/-25C...INCREASING 850-700 MOISTURE AND CLIMBING INVERSION
HEIGHTS. THE HIGHER RES MODELS SUGGEST THAT THE MOST FAVORABLE LOW
LEVEL CONV AND HIGHER LES POTENTIAL IN THE VEERING WIND PATTERN WILL
SET UP BETWEEN TWIN LAKES AND IRONWOOD BEFORE WINDS BEOMCE MORE NNW
LATER IN THE AFTERNOON. HIGHER TERRAIN LOCATIONS SHOULD SEE SNOW
AMOUNTS IN THE 3 TO 6 INCH RANGE WITH SOME LOCALLY HIGHER AMOUNTS
POSSIBLE. OVER THE EAST...THE WNW FLOW SHOULD CONFINE THE STRONGER
LES BANDS TO AREAS NEAR THE LAKE EAST OF MUNISING.
TONIGHT...THERE IS STILL UNCERTAINTY WITH HOW QUICKLY WINDS WILL
VEER OVER THE CNTRL AND EAST WHICH WILL PUSH THE STRONGER LES BANDS
INTO MARQUETTE COUNTY AND WRN ALGER COUNTY. MOST OF THE MODELS SUGGEST
THAT THIS WILL OCCUR AT OR LATER THAN 00Z WHEN THE MID LEVEL TROUGH
AXIS MOVES INTO ERN UPPER MI. THE NNW WINDS ARE EXPECTED TO GRADUALLY
VEER TO THE NNE TONIGHT. SO...THE GREATEST SNOWFALL RATES NEAR
MARQUETTE ARE EXPECTED LATE THIS EVENING AND THEN WILL SHIFT INTO THE
HIGHER TERRAIN TO THE WEST AS THE UPSLOPE COMPONENT STRENGTHENS. OVER
THE WEST...THE STRONGEST LOW LEVEL CONV IS EXPECTED INTO
IRONWOOD/WAKEFIELD/BERGLANDWITH SNOWBANDS ORIGINATING NEAR THUNDER
BAY. THE GREATEST SNOWFALL AMOUNTS TONIGHT SHOULD ALSO BE IN THE 3 TO
6 INCH RANGE.
WITH THE STRONGER UPWARD MOTION IN THE DGZ FOR MUCH OF THE
EVENT...SLR VALUES IN THE 20-25/1 RANGE ARE EXPECTED. THERE MAY ALSO
BE SOME GUSTY WINDS ALONG THE LAKESHORE TONIGHT WHERE WINDS MAY GUST
TO AROUND 30 MPH. ALTHOUGH THE SNOW MAY SLOW TRAVEL AND MAKE ROADS
HAZARDOUS BUT OVERALL IMPACTS ARE NOT EXPECTED TO BE SEVERE.
SO...GOING LES ADVISORY LEVEL HEADLINES FOR THE NORTHERN CWA IS ON
TRACK.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 443 AM EST TUE NOV 26 2013
LK EFFECT COVERAGE AND INTENSITY THROUGH THANKSGIVING IS THE MAIN
FORECAST FOCUS.
IN THE LARGER SCALE TO START WEDNESDAY...SHORTWAVE TROUGH THAT
HELPED TO IGNITE LATEST ROUND OF LAKE EFFECT WILL BE CROSSING LOWER
GREAT LAKES. TROUGH EVENTUALLY MEETS UP WITH PAIR OF SHORTWAVES
PUSHING OUT OF CNTRL AND SOUTHEAST CONUS TO HELP GIN UP STRONG
LOW PRESSURE SYSTEM OVER THE MID ATLANTIC STATES. THAT SYSTEM AND
ITS RAIN/SNOW AND WIND IMPACTS WILL BE PRIME FOCUS FOR THE WEATHER
ACROSS THE CONUS.
BACK ACROSS UPR MICHIGAN...MODERATE LK EFFECT WILL BE ONGOING FOR
NORTH FLOW AREAS. THOUGH THERE IS GRADUAL LOWERING OF INVERSIONS
THROUGH THE DAY ON WEDNESDAY...NORTH WINDS PERSIST IN THE LAKE
CONVECTIVE LAYER AND IT REMAINS PLENTY COLD ENOUGH WITH TEMPS AT
INVERSION TOP OF 5-7KFT STAYING IN THAT IDEAL RANGE OF -15C TO
-20C. BUFKIT COBB OUTPUT SUGGESTS SLR/S AT IWD AND MQT POINTS
NEARING 30:1. CUT THESE SLIGHTLY THOUGH DUE TO SOME FRACTURING OF
SNOWFLAKES WITH WINDS AOA 20 KTS BLO CLOUD BASE. LK EFFECT ADVYS IN
THE SHORT TERM WILL CARRY THROUGH MIDDAY WEDNESDAY IN THE FAR WEST
AND INTO LATE AFTN FOR MARQUETTE COUNTY INTO WESTERN ALGER COUNTY.
EXPECT ADDITIONAL DAYTIME SNOW ACCUMS UP TO 5 INCHES...GREATEST
FOR THE HIGHER TERRAIN OF WESTERN MARQUETTE COUNTY WITH EXPECTED
NNE WINDS BLO 5KFT. AS AFTN WEARS ON...INTENSITY OF SNOW SHOWERS
SHOULD START TO RELAX AS H85-H7 MOISTURE THINS OUT AND LOW-LEVEL
WINDS BECOME MORE ANTICYLONIC...ESPECIALLY FOR FAR WESTERN CWA. AWAY
FM LK EFFECT SHOULD BE GENERALLY CLOUDY DAY AS SOUNDINGS SHOW H85-H8
MOISTURE DUE TO WINDS FLOWING OFF LK SUPERIOR...STAYS TRAPPED
BENEATH LARGER SCALE SUBSIDENCE WHICH IS PRETTY TYPICAL FOR THIS
TIME OF YEAR GIVEN THE LOW SUN ANGLE. TEMPS WILL BE IN THE 20S
ACROSS THE AREA.
WEAKENING LOW-LEVEL FLOW ALLOWS MESOSCALE TO BECOME MAIN DRIVER FOR
CONVERGENCE/LK EFFECT AREAS ON WEDNESDAY NIGHT. LEANED ON THE NAM AS
OUTPUT MADE A LOT OF SENSE WITH EXPECTED SFC PATTERN AND WINDS AT H9
WHICH WILL BE IN THE LAKE CLOUD-BEARING LAYER. AS RETURN FLOW TRIES
TO GET GOING AND ALSO DUE TO LAND BREEZE...MESOLOW PROBABLY FORMS BY
WED EVENING JUST ALONG SHORE FM SAXON HARBOR TO SILVER CITY. AS H9
WINDS BECOME MORE SW...EXPECT SNOW SHOWERS TO LIFT TOWARD KEWEENAW
LATE. MODERATE SNOWS MAY BE ONGOING...BUT IMPACT WOULD BE LIMITED TO
FAR WESTERN SHORE OF KEWEENAW PENINSULA. FARTHER EAST...EXPECT
SIMILAR SETUP IN THE MARQUETTE AREA. WINDS SLOWLY BACKING NRLY IN
THE EVENING LIKELY WILL PUSH SNOW SHOWERS OFF THE HIGHLANDS OF
WESTERN MARQUETTE COUNTY AND TOWARD THE LK SUPERIOR SHORE AND INTO
EASTERN PORTIONS OF MARQUETTE COUNTY. LAND BREEZE MAY ALLOW FOR
DECENT CONVERGENT BAND SOMEWHERE BTWN MARQUETTE/HARVEY AND AU TRAIN.
MINIMAL CHANGE IN H925-H85 TEMPS AND INVERSION HEIGHTS ON WEDNESDAY
NIGHT WOULD ALLOW FOR AT LEAST MODERATE SNOW ACCUMS WITHIN THIS
CONVERGENT AREA. THIS MAY POSE SOME PROBLEM FOR THE ENDING OF THE
HEADLINE ON WEDNESDAY AFTN...BUT WILL LET LATER SHIFTS EXTEND THE
ADVY IF IT IS NEEDED AS DO NOT KNOW EXACTLY WHERE THE HEAVIER SNOW
WOULD END UP. POSSIBLE THAT BAND OF SNOW WILL STILL BE AROUND FOR
DAYBREAK ON THANKSGIVING...BUT THINK THAT THE RETURN FLOW OVER THE
WEST WILL MAKE ITS WAY EAST AND KICK THE MAIN SNOW SHOWERS OUT
ACROSS LK SUPERIOR. SOUNDINGS SHOW INCREASE IN MID-LEVEL MOISTURE
LATE WEDNESDAY NIGHT AS ANOTHER SHORTWAVE DROPS ACROSS UPR LAKES IN
NW FLOW. SMALL POPS AWAY FM LK EFFECT AREAS LATE IN THE WEST TO
ACCOUNT FOR THE SHORTWAVE.
SHORTWAVE CROSSES THE AREA ON THANKSGIVING...MAINLY THROUGH MID AFTN.
ALSO A BIT OF A WEAK SFC TROUGH TOO. SOUNDINGS SHOW DECENT LIFT
OCCURRING FM H9-H7 WHICH IS FIRMLY WHERE THE DGZ RESIDES. EVEN WITH
A BIT OF DRY AIR BLO H85...THINK THE LIFT AND MOISTENING FM ABOVE
WILL BE ENOUGH TO PRODUCE LGT SNOW OVER MUCH OF THE CWA...EXCEPT
MAYBE THE FAR SCNTRL. AMOUNTS WILL BE LESS THAN AN INCH. ONE
EXCEPTION TO THAT COULD BE OVER THE KEWEENAW WHERE ONSHORE
FLOW/CONVERGENCE COULD BOOST SNOW AMOUNTS ALONG TIP OF THE KEWEENAW.
NOT EXPECTING ANY HEADLINE AMOUNTS THOUGH AS WIND FIELDS ARE PRETTY
VARIABLE INDICATING SNOW SHOWERS WILL NOT REMAIN IN ANY ONE LOCATION
VERY LONG. LATEST RUNS SHOW ENOUGH OF SW PUSH IN AFTN TO ADVECT SNOW
SHOWERS OUT OVER NCNTRL LK SUPERIOR. GFS/ECMWF INDICATE LOW PRESSURE
TROUGH THAT IS LEFT BEHIND IN WAKE OF SHORTWAVE SHOULD SINK BACK INTO
AT LEAST NORTHWEST CWA LATER THURSDAY NIGHT. CHANCE POPS FOR SNOW
SHOWERS WERE CARRIED FOR THAT TIME AND INTO FRIDAY AS WELL. EXPECTED
N FLOW IN WAKE OF TROUGH ALSO RESULTED IN LOWER CHANCES LINGERING
INTO NCNTRL CWA. TROUGH AND ANY LINGERING SNOW SHOWERS DISSIPATE BY
FRIDAY EVENING AS PRESSURE GRADIENT REGROUPS AHEAD OF DEVELOPING
TROUGH OVR SCNTRL CANADA.
SHORTWAVE AND SFC TROUGH STAY MAINLY TO THE NORTH OF UPR LAKES FOR
THE UPCOMING WEEKEND. BEST SHOT OF LGT SNOW WILL BE OVR LK SUPERIOR
ON SATURDAY CLOSER TO THE SHORTWAVE/Q-VECTOR CONVERGENCE AND MORE
SATURATED LOW-LEVELS. A LOT OF CLOUD COVER OVER REST OF CWA ALONG
WITH BREEZY SOUTH WIND THAT WILL BRING A RETURN OF SLIGHTLY ABOVE
FREEZING TEMPS OVER MUCH OF CWA. RAN WITH CONSENSUS BEYOND SATURDAY
WITH DIFFERENCES SHOWING UP IN HOW QUICK TO BRING NEXT SHORTWAVE AND
SFC TROUGH/PRECIP INTO UPR LAKES. DOES LOOK LIKE TEMPS WILL STAY
RELATIVELY WARMER /HIGHS IN THE 30S COMPARED TO TEENS OR 20S/ BEFORE
ANOTHER PUSH OF COLDER AIR ARRIVES JUST BEYOND THE SCOPE OF THE LONG
TERM TIME RANGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1242 PM EST TUE NOV 26 2013
KCMX...EXPECT IFR CONDITIONS THROUGH MUCH OF THE PERIOD IN LAKE
EFFECT SNOW AND SOME BLOWING OF SNOW DUE TO WINDS GUSTING NEAR 25
MPH. WINDS WILL SHIFT FROM NW TO N LATER THIS EVENING CONTINUING INTO
WEDNESDAY.
KIWD...EXPECT MVFR CONDITIONS TO OCCASIONAL IFR CONDITIONS TODAY IN
NW FLOW LAKE EFFECT. CONDITIONS WILL DETERIORATE TO LIFR LATER THIS
EVENING AS WINDS SHIFT NORTHERLY AND LAKE EFFECT SNOW INCREASES.
KSAW....MVFR CONDITIONS IN SCT LAKE EFFECT SNOW WILL DETERIORATE TO
IFR AND PERHAPS EVEN OCCASIONALLY LIFR LATE TONIGHT INTO WEDNESDAY AS
WINDS SHIFT FROM NW TO N AS LAKE EFFECT SNOW INCREASES IN INTENSITY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 AM EST TUE NOV 26 2013
NW WINDS TO 30 KTS TODAY AS WE ARE IN THE WAKE OF COLD FRONT THAT
MOVED THROUGH MONDAY EVENING. ANOTHER TROUGH DROPS SOUTH ACROSS LK
SUPERIOR LATE TODAY AND THIS EVENING RESULTING IN WINDS SHIFTING TO
NORTH OR NORTHEAST. GALES LOOK LIKELY OVER MAINLY EAST HALF SO GALE
WARNING HAS BEEN POSTED. GALES LINGER INTO WEDNESDAY BEFORE WINDS
QUICKLY DIMINISH TO LESS THAN 20 KTS AS WEAK PRESSURE GRADIENT
DEVELOPS FOR THANKSGIVING. WINDS STAY LIGHT UNTIL SATURDAY WHEN
SOUTH WINDS INCREASE AHEAD OF LOW PRESSURE SYSTEM CROSSING SCNTRL
CANADA. WINDS MAY REACH 30 KTS OVER EASTERN SECTIONS INTO SATURDAY
EVENING. MORE LIGHT WINDS TO END THE WEEKEND AS PRESSURE GRADIENT
RELAXES AGAIN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 3 PM EST
WEDNESDAY FOR MIZ005.
LAKE EFFECT SNOW ADVISORY UNTIL NOON EST /11 AM CST/ WEDNESDAY
FOR MIZ002-009.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001-
003.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ004-
084.
LAKE EFFECT SNOW ADVISORY UNTIL 3 PM EST WEDNESDAY FOR MIZ006.
LAKE SUPERIOR...
GALE WARNING FROM 1 AM TO 1 PM EST WEDNESDAY FOR LSZ266-267.
GALE WARNING FROM 1 AM TO 10 AM EST WEDNESDAY FOR LSZ265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...VOSS
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
701 AM EST TUE NOV 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EST TUE NOV 26 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A WELL DEFINED UPSTREAM
MID/UPPER LEVEL LOW/SHORTWAVE TROUGH FROM NW OF LAKE SUPERIOR INTO
NW MN. AT THE SFC...LOW PRES WAS LOCATED NE OF LAKE SUPERIOR(NEAR
WAWA ONTARIO) WITH A COLD FRONT EXTENDING THROUGH WHITEFISH BAY INTO
NW LOWER MI AND A TROUGH STRETCHING TO THE WEST. 700-300 QVECTOR
CONV AHEAD OF THE SHRTWV SUPPORTED SCT -SHSN/FLURRIES FROM NE MN
INTO CNTRL UPPER MI. RADAR ALSO INDICATED AN INCREASE IN LES FROM
FROM NEAR BIG BAY EASTWARD ALIGNED WITH 280-290 LOW LEVEL FLOW.
HOWEVER...WEBCAMS AND SFC OBS OVER WRN UPPER MI DID NOT SHOW A
SIGNFICANT INCREASE IN SNOW INTENSITY OVERNIGHT.
TODAY...EXPECT LES TO INCREASE THIS MORNING OVER THE WEST AS THE MID
LEVEL LOW SLIDES TO THE SOUTHEAST WITH 850/700 MB TEMPS DROPPING TO
-17C/-25C...INCREASING 850-700 MOISTURE AND CLIMBING INVERSION
HEIGHTS. THE HIGHER RES MODELS SUGGEST THAT THE MOST FAVORABLE LOW
LEVEL CONV AND HIGHER LES POTENTIAL IN THE VEERING WIND PATTERN WILL
SET UP BETWEEN TWIN LAKES AND IRONWOOD BEFORE WINDS BEOMCE MORE NNW
LATER IN THE AFTERNOON. HIGHER TERRAIN LOCATIONS SHOULD SEE SNOW
AMOUNTS IN THE 3 TO 6 INCH RANGE WITH SOME LOCALLY HIGHER AMOUNTS
POSSIBLE. OVER THE EAST...THE WNW FLOW SHOULD CONFINE THE STRONGER
LES BANDS TO AREAS NEAR THE LAKE EAST OF MUNISING.
TONIGHT...THERE IS STILL UNCERTAINTY WITH HOW QUICKLY WINDS WILL
VEER OVER THE CNTRL AND EAST WHICH WILL PUSH THE STRONGER LES BANDS
INTO MARQUETTE COUNTY AND WRN ALGER COUNTY. MOST OF THE MODELS SUGGEST
THAT THIS WILL OCCUR AT OR LATER THAN 00Z WHEN THE MID LEVEL TROUGH
AXIS MOVES INTO ERN UPPER MI. THE NNW WINDS ARE EXPECTED TO GRADUALLY
VEER TO THE NNE TONIGHT. SO...THE GREATEST SNOWFALL RATES NEAR
MARQUETTE ARE EXPECTED LATE THIS EVENING AND THEN WILL SHIFT INTO THE
HIGHER TERRAIN TO THE WEST AS THE UPSLOPE COMPONENT STRENGTHENS. OVER
THE WEST...THE STRONGEST LOW LEVEL CONV IS EXPECTED INTO
IRONWOOD/WAKEFIELD/BERGLANDWITH SNOWBANDS ORIGINATING NEAR THUNDER
BAY. THE GREATEST SNOWFALL AMOUNTS TONIGHT SHOULD ALSO BE IN THE 3 TO
6 INCH RANGE.
WITH THE STRONGER UPWARD MOTION IN THE DGZ FOR MUCH OF THE
EVENT...SLR VALUES IN THE 20-25/1 RANGE ARE EXPECTED. THERE MAY ALSO
BE SOME GUSTY WINDS ALONG THE LAKESHORE TONIGHT WHERE WINDS MAY GUST
TO AROUND 30 MPH. ALTHOUGH THE SNOW MAY SLOW TRAVEL AND MAKE ROADS
HAZARDOUS BUT OVERALL IMPACTS ARE NOT EXPECTED TO BE SEVERE.
SO...GOING LES ADVISORY LEVEL HEADLINES FOR THE NORTHERN CWA IS ON
TRACK.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 443 AM EST TUE NOV 26 2013
LK EFFECT COVERAGE AND INTENSITY THROUGH THANKSGIVING IS THE MAIN
FORECAST FOCUS.
IN THE LARGER SCALE TO START WEDNESDAY...SHORTWAVE TROUGH THAT
HELPED TO IGNITE LATEST ROUND OF LAKE EFFECT WILL BE CROSSING LOWER
GREAT LAKES. TROUGH EVENTUALLY MEETS UP WITH PAIR OF SHORTWAVES
PUSHING OUT OF CNTRL AND SOUTHEAST CONUS TO HELP GIN UP STRONG
LOW PRESSURE SYSTEM OVER THE MID ATLANTIC STATES. THAT SYSTEM AND
ITS RAIN/SNOW AND WIND IMPACTS WILL BE PRIME FOCUS FOR THE WEATHER
ACROSS THE CONUS.
BACK ACROSS UPR MICHIGAN...MODERATE LK EFFECT WILL BE ONGOING FOR
NORTH FLOW AREAS. THOUGH THERE IS GRADUAL LOWERING OF INVERSIONS
THROUGH THE DAY ON WEDNESDAY...NORTH WINDS PERSIST IN THE LAKE
CONVECTIVE LAYER AND IT REMAINS PLENTY COLD ENOUGH WITH TEMPS AT
INVERSION TOP OF 5-7KFT STAYING IN THAT IDEAL RANGE OF -15C TO
-20C. BUFKIT COBB OUTPUT SUGGESTS SLR/S AT IWD AND MQT POINTS
NEARING 30:1. CUT THESE SLIGHTLY THOUGH DUE TO SOME FRACTURING OF
SNOWFLAKES WITH WINDS AOA 20 KTS BLO CLOUD BASE. LK EFFECT ADVYS IN
THE SHORT TERM WILL CARRY THROUGH MIDDAY WEDNESDAY IN THE FAR WEST
AND INTO LATE AFTN FOR MARQUETTE COUNTY INTO WESTERN ALGER COUNTY.
EXPECT ADDITIONAL DAYTIME SNOW ACCUMS UP TO 5 INCHES...GREATEST
FOR THE HIGHER TERRAIN OF WESTERN MARQUETTE COUNTY WITH EXPECTED
NNE WINDS BLO 5KFT. AS AFTN WEARS ON...INTENSITY OF SNOW SHOWERS
SHOULD START TO RELAX AS H85-H7 MOISTURE THINS OUT AND LOW-LEVEL
WINDS BECOME MORE ANTICYLONIC...ESPECIALLY FOR FAR WESTERN CWA. AWAY
FM LK EFFECT SHOULD BE GENERALLY CLOUDY DAY AS SOUNDINGS SHOW H85-H8
MOISTURE DUE TO WINDS FLOWING OFF LK SUPERIOR...STAYS TRAPPED
BENEATH LARGER SCALE SUBSIDENCE WHICH IS PRETTY TYPICAL FOR THIS
TIME OF YEAR GIVEN THE LOW SUN ANGLE. TEMPS WILL BE IN THE 20S
ACROSS THE AREA.
WEAKENING LOW-LEVEL FLOW ALLOWS MESOSCALE TO BECOME MAIN DRIVER FOR
CONVERGENCE/LK EFFECT AREAS ON WEDNESDAY NIGHT. LEANED ON THE NAM AS
OUTPUT MADE A LOT OF SENSE WITH EXPECTED SFC PATTERN AND WINDS AT H9
WHICH WILL BE IN THE LAKE CLOUD-BEARING LAYER. AS RETURN FLOW TRIES
TO GET GOING AND ALSO DUE TO LAND BREEZE...MESOLOW PROBABLY FORMS BY
WED EVENING JUST ALONG SHORE FM SAXON HARBOR TO SILVER CITY. AS H9
WINDS BECOME MORE SW...EXPECT SNOW SHOWERS TO LIFT TOWARD KEWEENAW
LATE. MODERATE SNOWS MAY BE ONGOING...BUT IMPACT WOULD BE LIMITED TO
FAR WESTERN SHORE OF KEWEENAW PENINSULA. FARTHER EAST...EXPECT
SIMILAR SETUP IN THE MARQUETTE AREA. WINDS SLOWLY BACKING NRLY IN
THE EVENING LIKELY WILL PUSH SNOW SHOWERS OFF THE HIGHLANDS OF
WESTERN MARQUETTE COUNTY AND TOWARD THE LK SUPERIOR SHORE AND INTO
EASTERN PORTIONS OF MARQUETTE COUNTY. LAND BREEZE MAY ALLOW FOR
DECENT CONVERGENT BAND SOMEWHERE BTWN MARQUETTE/HARVEY AND AU TRAIN.
MINIMAL CHANGE IN H925-H85 TEMPS AND INVERSION HEIGHTS ON WEDNESDAY
NIGHT WOULD ALLOW FOR AT LEAST MODERATE SNOW ACCUMS WITHIN THIS
CONVERGENT AREA. THIS MAY POSE SOME PROBLEM FOR THE ENDING OF THE
HEADLINE ON WEDNESDAY AFTN...BUT WILL LET LATER SHIFTS EXTEND THE
ADVY IF IT IS NEEDED AS DO NOT KNOW EXACTLY WHERE THE HEAVIER SNOW
WOULD END UP. POSSIBLE THAT BAND OF SNOW WILL STILL BE AROUND FOR
DAYBREAK ON THANKSGIVING...BUT THINK THAT THE RETURN FLOW OVER THE
WEST WILL MAKE ITS WAY EAST AND KICK THE MAIN SNOW SHOWERS OUT
ACROSS LK SUPERIOR. SOUNDINGS SHOW INCREASE IN MID-LEVEL MOISTURE
LATE WEDNESDAY NIGHT AS ANOTHER SHORTWAVE DROPS ACROSS UPR LAKES IN
NW FLOW. SMALL POPS AWAY FM LK EFFECT AREAS LATE IN THE WEST TO
ACCOUNT FOR THE SHORTWAVE.
SHORTWAVE CROSSES THE AREA ON THANKSGIVING...MAINLY THROUGH MID AFTN.
ALSO A BIT OF A WEAK SFC TROUGH TOO. SOUNDINGS SHOW DECENT LIFT
OCCURRING FM H9-H7 WHICH IS FIRMLY WHERE THE DGZ RESIDES. EVEN WITH
A BIT OF DRY AIR BLO H85...THINK THE LIFT AND MOISTENING FM ABOVE
WILL BE ENOUGH TO PRODUCE LGT SNOW OVER MUCH OF THE CWA...EXCEPT
MAYBE THE FAR SCNTRL. AMOUNTS WILL BE LESS THAN AN INCH. ONE
EXCEPTION TO THAT COULD BE OVER THE KEWEENAW WHERE ONSHORE
FLOW/CONVERGENCE COULD BOOST SNOW AMOUNTS ALONG TIP OF THE KEWEENAW.
NOT EXPECTING ANY HEADLINE AMOUNTS THOUGH AS WIND FIELDS ARE PRETTY
VARIABLE INDICATING SNOW SHOWERS WILL NOT REMAIN IN ANY ONE LOCATION
VERY LONG. LATEST RUNS SHOW ENOUGH OF SW PUSH IN AFTN TO ADVECT SNOW
SHOWERS OUT OVER NCNTRL LK SUPERIOR. GFS/ECMWF INDICATE LOW PRESSURE
TROUGH THAT IS LEFT BEHIND IN WAKE OF SHORTWAVE SHOULD SINK BACK INTO
AT LEAST NORTHWEST CWA LATER THURSDAY NIGHT. CHANCE POPS FOR SNOW
SHOWERS WERE CARRIED FOR THAT TIME AND INTO FRIDAY AS WELL. EXPECTED
N FLOW IN WAKE OF TROUGH ALSO RESULTED IN LOWER CHANCES LINGERING
INTO NCNTRL CWA. TROUGH AND ANY LINGERING SNOW SHOWERS DISSIPATE BY
FRIDAY EVENING AS PRESSURE GRADIENT REGROUPS AHEAD OF DEVELOPING
TROUGH OVR SCNTRL CANADA.
SHORTWAVE AND SFC TROUGH STAY MAINLY TO THE NORTH OF UPR LAKES FOR
THE UPCOMING WEEKEND. BEST SHOT OF LGT SNOW WILL BE OVR LK SUPERIOR
ON SATURDAY CLOSER TO THE SHORTWAVE/Q-VECTOR CONVERGENCE AND MORE
SATURATED LOW-LEVELS. A LOT OF CLOUD COVER OVER REST OF CWA ALONG
WITH BREEZY SOUTH WIND THAT WILL BRING A RETURN OF SLIGHTLY ABOVE
FREEZING TEMPS OVER MUCH OF CWA. RAN WITH CONSENSUS BEYOND SATURDAY
WITH DIFFERENCES SHOWING UP IN HOW QUICK TO BRING NEXT SHORTWAVE AND
SFC TROUGH/PRECIP INTO UPR LAKES. DOES LOOK LIKE TEMPS WILL STAY
RELATIVELY WARMER /HIGHS IN THE 30S COMPARED TO TEENS OR 20S/ BEFORE
ANOTHER PUSH OF COLDER AIR ARRIVES JUST BEYOND THE SCOPE OF THE LONG
TERM TIME RANGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 700 AM EST TUE NOV 26 2013
THE PASSAGE OF A LOW PRES TROUGH WILL BRING INCREASING LES INTENSITY
AT IWD/CMX THIS MORNING WITH OCNL IFR CONDITIONS LIKELY. AFTER
ANOTHER LOW PRES TROUGH TRACKS THROUGH THE AREA IN THE EVENING...A
WIND SHIFT TO A MORE N DIRECTION WILL NOT FAVOR CMX...SO MVFR
CONDITIONS ARE EXPECTED THERE. ON THE OTHER HAND...THE WIND SHIFT
WILL FAVOR IWD...SO IFR CONDITIONS SHOULD PREVAIL THERE LATE IN THE
FCST PERIOD. EXPECT VFR WX AT SAW TO PREDOMINATE INTO THIS EVENING WITH
A DOWNSLOPE WIND COMPONENT. BUT CONDITIONS THERE ARE LIKELY TO
DETERIORATE QUICKLY LATE IN THE PERIOD WITH THE WIND SHIFT TO A
FAVORABLE UPSLOPE N DIRECTION FOLLOWING THE LOW PRES TROUGH PASSAGE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 AM EST TUE NOV 26 2013
NW WINDS TO 30 KTS TODAY AS WE ARE IN THE WAKE OF COLD FRONT THAT
MOVED THROUGH MONDAY EVENING. ANOTHER TROUGH DROPS SOUTH ACROSS LK
SUPERIOR LATE TODAY AND THIS EVENING RESULTING IN WINDS SHIFTING TO
NORTH OR NORTHEAST. GALES LOOK LIKELY OVER MAINLY EAST HALF SO GALE
WARNING HAS BEEN POSTED. GALES LINGER INTO WEDNESDAY BEFORE WINDS
QUICKLY DIMINISH TO LESS THAN 20 KTS AS WEAK PRESSURE GRADIENT
DEVELOPS FOR THANKSGIVING. WINDS STAY LIGHT UNTIL SATURDAY WHEN
SOUTH WINDS INCREASE AHEAD OF LOW PRESSURE SYSTEM CROSSING SCNTRL
CANADA. WINDS MAY REACH 30 KTS OVER EASTERN SECTIONS INTO SATURDAY
EVENING. MORE LIGHT WINDS TO END THE WEEKEND AS PRESSURE GRADIENT
RELAXES AGAIN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 3 PM EST
WEDNESDAY FOR MIZ005.
LAKE EFFECT SNOW ADVISORY UNTIL NOON EST /11 AM CST/ WEDNESDAY
FOR MIZ002-009.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001-
003.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ004-
084.
LAKE EFFECT SNOW ADVISORY FROM 3 PM THIS AFTERNOON TO 3 PM EST
WEDNESDAY FOR MIZ006.
LAKE SUPERIOR...
GALE WARNING FROM 1 AM TO 1 PM EST WEDNESDAY FOR LSZ266-267.
GALE WARNING FROM 1 AM TO 10 AM EST WEDNESDAY FOR LSZ265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
519 AM EST TUE NOV 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EST TUE NOV 26 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A WELL DEFINED UPSTREAM
MID/UPPER LEVEL LOW/SHORTWAVE TROUGH FROM NW OF LAKE SUPERIOR INTO
NW MN. AT THE SFC...LOW PRES WAS LOCATED NE OF LAKE SUPERIOR(NEAR
WAWA ONTARIO) WITH A COLD FRONT EXTENDING THROUGH WHITEFISH BAY INTO
NW LOWER MI AND A TROUGH STRETCHING TO THE WEST. 700-300 QVECTOR
CONV AHEAD OF THE SHRTWV SUPPORTED SCT -SHSN/FLURRIES FROM NE MN
INTO CNTRL UPPER MI. RADAR ALSO INDICATED AN INCREASE IN LES FROM
FROM NEAR BIG BAY EASTWARD ALIGNED WITH 280-290 LOW LEVEL FLOW.
HOWEVER...WEBCAMS AND SFC OBS OVER WRN UPPER MI DID NOT SHOW A
SIGNFICANT INCREASE IN SNOW INTENSITY OVERNIGHT.
TODAY...EXPECT LES TO INCREASE THIS MORNING OVER THE WEST AS THE MID
LEVEL LOW SLIDES TO THE SOUTHEAST WITH 850/700 MB TEMPS DROPPING TO
-17C/-25C...INCREASING 850-700 MOISTURE AND CLIMBING INVERSION
HEIGHTS. THE HIGHER RES MODELS SUGGEST THAT THE MOST FAVORABLE LOW
LEVEL CONV AND HIGHER LES POTENTIAL IN THE VEERING WIND PATTERN WILL
SET UP BETWEEN TWIN LAKES AND IRONWOOD BEFORE WINDS BEOMCE MORE NNW
LATER IN THE AFTERNOON. HIGHER TERRAIN LOCATIONS SHOULD SEE SNOW
AMOUNTS IN THE 3 TO 6 INCH RANGE WITH SOME LOCALLY HIGHER AMOUNTS
POSSIBLE. OVER THE EAST...THE WNW FLOW SHOULD CONFINE THE STRONGER
LES BANDS TO AREAS NEAR THE LAKE EAST OF MUNISING.
TONIGHT...THERE IS STILL UNCERTAINTY WITH HOW QUICKLY WINDS WILL
VEER OVER THE CNTRL AND EAST WHICH WILL PUSH THE STRONGER LES BANDS
INTO MARQUETTE COUNTY AND WRN ALGER COUNTY. MOST OF THE MODELS SUGGEST
THAT THIS WILL OCCUR AT OR LATER THAN 00Z WHEN THE MID LEVEL TROUGH
AXIS MOVES INTO ERN UPPER MI. THE NNW WINDS ARE EXPECTED TO GRADUALLY
VEER TO THE NNE TONIGHT. SO...THE GREATEST SNOWFALL RATES NEAR
MARQUETTE ARE EXPECTED LATE THIS EVENING AND THEN WILL SHIFT INTO THE
HIGHER TERRAIN TO THE WEST AS THE UPSLOPE COMPONENT STRENGTHENS. OVER
THE WEST...THE STRONGEST LOW LEVEL CONV IS EXPECTED INTO
IRONWOOD/WAKEFIELD/BERGLANDWITH SNOWBANDS ORIGINATING NEAR THUNDER
BAY. THE GREATEST SNOWFALL AMOUNTS TONIGHT SHOULD ALSO BE IN THE 3 TO
6 INCH RANGE.
WITH THE STRONGER UPWARD MOTION IN THE DGZ FOR MUCH OF THE
EVENT...SLR VALUES IN THE 20-25/1 RANGE ARE EXPECTED. THERE MAY ALSO
BE SOME GUSTY WINDS ALONG THE LAKESHORE TONIGHT WHERE WINDS MAY GUST
TO AROUND 30 MPH. ALTHOUGH THE SNOW MAY SLOW TRAVEL AND MAKE ROADS
HAZARDOUS BUT OVERALL IMPACTS ARE NOT EXPECTED TO BE SEVERE.
SO...GOING LES ADVISORY LEVEL HEADLINES FOR THE NORTHERN CWA IS ON
TRACK.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 443 AM EST TUE NOV 26 2013
LK EFFECT COVERAGE AND INTENSITY THROUGH THANKSGIVING IS THE MAIN
FORECAST FOCUS.
IN THE LARGER SCALE TO START WEDNESDAY...SHORTWAVE TROUGH THAT
HELPED TO IGNITE LATEST ROUND OF LAKE EFFECT WILL BE CROSSING LOWER
GREAT LAKES. TROUGH EVENTUALLY MEETS UP WITH PAIR OF SHORTWAVES
PUSHING OUT OF CNTRL AND SOUTHEAST CONUS TO HELP GIN UP STRONG
LOW PRESSURE SYSTEM OVER THE MID ATLANTIC STATES. THAT SYSTEM AND
ITS RAIN/SNOW AND WIND IMPACTS WILL BE PRIME FOCUS FOR THE WEATHER
ACROSS THE CONUS.
BACK ACROSS UPR MICHIGAN...MODERATE LK EFFECT WILL BE ONGOING FOR
NORTH FLOW AREAS. THOUGH THERE IS GRADUAL LOWERING OF INVERSIONS
THROUGH THE DAY ON WEDNESDAY...NORTH WINDS PERSIST IN THE LAKE
CONVECTIVE LAYER AND IT REMAINS PLENTY COLD ENOUGH WITH TEMPS AT
INVERSION TOP OF 5-7KFT STAYING IN THAT IDEAL RANGE OF -15C TO
-20C. BUFKIT COBB OUTPUT SUGGESTS SLR/S AT IWD AND MQT POINTS
NEARING 30:1. CUT THESE SLIGHTLY THOUGH DUE TO SOME FRACTURING OF
SNOWFLAKES WITH WINDS AOA 20 KTS BLO CLOUD BASE. LK EFFECT ADVYS IN
THE SHORT TERM WILL CARRY THROUGH MIDDAY WEDNESDAY IN THE FAR WEST
AND INTO LATE AFTN FOR MARQUETTE COUNTY INTO WESTERN ALGER COUNTY.
EXPECT ADDITIONAL DAYTIME SNOW ACCUMS UP TO 5 INCHES...GREATEST
FOR THE HIGHER TERRAIN OF WESTERN MARQUETTE COUNTY WITH EXPECTED
NNE WINDS BLO 5KFT. AS AFTN WEARS ON...INTENSITY OF SNOW SHOWERS
SHOULD START TO RELAX AS H85-H7 MOISTURE THINS OUT AND LOW-LEVEL
WINDS BECOME MORE ANTICYLONIC...ESPECIALLY FOR FAR WESTERN CWA. AWAY
FM LK EFFECT SHOULD BE GENERALLY CLOUDY DAY AS SOUNDINGS SHOW H85-H8
MOISTURE DUE TO WINDS FLOWING OFF LK SUPERIOR...STAYS TRAPPED
BENEATH LARGER SCALE SUBSIDENCE WHICH IS PRETTY TYPICAL FOR THIS
TIME OF YEAR GIVEN THE LOW SUN ANGLE. TEMPS WILL BE IN THE 20S
ACROSS THE AREA.
WEAKENING LOW-LEVEL FLOW ALLOWS MESOSCALE TO BECOME MAIN DRIVER FOR
CONVERGENCE/LK EFFECT AREAS ON WEDNESDAY NIGHT. LEANED ON THE NAM AS
OUTPUT MADE A LOT OF SENSE WITH EXPECTED SFC PATTERN AND WINDS AT H9
WHICH WILL BE IN THE LAKE CLOUD-BEARING LAYER. AS RETURN FLOW TRIES
TO GET GOING AND ALSO DUE TO LAND BREEZE...MESOLOW PROBABLY FORMS BY
WED EVENING JUST ALONG SHORE FM SAXON HARBOR TO SILVER CITY. AS H9
WINDS BECOME MORE SW...EXPECT SNOW SHOWERS TO LIFT TOWARD KEWEENAW
LATE. MODERATE SNOWS MAY BE ONGOING...BUT IMPACT WOULD BE LIMITED TO
FAR WESTERN SHORE OF KEWEENAW PENINSULA. FARTHER EAST...EXPECT
SIMILAR SETUP IN THE MARQUETTE AREA. WINDS SLOWLY BACKING NRLY IN
THE EVENING LIKELY WILL PUSH SNOW SHOWERS OFF THE HIGHLANDS OF
WESTERN MARQUETTE COUNTY AND TOWARD THE LK SUPERIOR SHORE AND INTO
EASTERN PORTIONS OF MARQUETTE COUNTY. LAND BREEZE MAY ALLOW FOR
DECENT CONVERGENT BAND SOMEWHERE BTWN MARQUETTE/HARVEY AND AU TRAIN.
MINIMAL CHANGE IN H925-H85 TEMPS AND INVERSION HEIGHTS ON WEDNESDAY
NIGHT WOULD ALLOW FOR AT LEAST MODERATE SNOW ACCUMS WITHIN THIS
CONVERGENT AREA. THIS MAY POSE SOME PROBLEM FOR THE ENDING OF THE
HEADLINE ON WEDNESDAY AFTN...BUT WILL LET LATER SHIFTS EXTEND THE
ADVY IF IT IS NEEDED AS DO NOT KNOW EXACTLY WHERE THE HEAVIER SNOW
WOULD END UP. POSSIBLE THAT BAND OF SNOW WILL STILL BE AROUND FOR
DAYBREAK ON THANKSGIVING...BUT THINK THAT THE RETURN FLOW OVER THE
WEST WILL MAKE ITS WAY EAST AND KICK THE MAIN SNOW SHOWERS OUT
ACROSS LK SUPERIOR. SOUNDINGS SHOW INCREASE IN MID-LEVEL MOISTURE
LATE WEDNESDAY NIGHT AS ANOTHER SHORTWAVE DROPS ACROSS UPR LAKES IN
NW FLOW. SMALL POPS AWAY FM LK EFFECT AREAS LATE IN THE WEST TO
ACCOUNT FOR THE SHORTWAVE.
SHORTWAVE CROSSES THE AREA ON THANKSGIVING...MAINLY THROUGH MID AFTN.
ALSO A BIT OF A WEAK SFC TROUGH TOO. SOUNDINGS SHOW DECENT LIFT
OCCURRING FM H9-H7 WHICH IS FIRMLY WHERE THE DGZ RESIDES. EVEN WITH
A BIT OF DRY AIR BLO H85...THINK THE LIFT AND MOISTENING FM ABOVE
WILL BE ENOUGH TO PRODUCE LGT SNOW OVER MUCH OF THE CWA...EXCEPT
MAYBE THE FAR SCNTRL. AMOUNTS WILL BE LESS THAN AN INCH. ONE
EXCEPTION TO THAT COULD BE OVER THE KEWEENAW WHERE ONSHORE
FLOW/CONVERGENCE COULD BOOST SNOW AMOUNTS ALONG TIP OF THE KEWEENAW.
NOT EXPECTING ANY HEADLINE AMOUNTS THOUGH AS WIND FIELDS ARE PRETTY
VARIABLE INDICATING SNOW SHOWERS WILL NOT REMAIN IN ANY ONE LOCATION
VERY LONG. LATEST RUNS SHOW ENOUGH OF SW PUSH IN AFTN TO ADVECT SNOW
SHOWERS OUT OVER NCNTRL LK SUPERIOR. GFS/ECMWF INDICATE LOW PRESSURE
TROUGH THAT IS LEFT BEHIND IN WAKE OF SHORTWAVE SHOULD SINK BACK INTO
AT LEAST NORTHWEST CWA LATER THURSDAY NIGHT. CHANCE POPS FOR SNOW
SHOWERS WERE CARRIED FOR THAT TIME AND INTO FRIDAY AS WELL. EXPECTED
N FLOW IN WAKE OF TROUGH ALSO RESULTED IN LOWER CHANCES LINGERING
INTO NCNTRL CWA. TROUGH AND ANY LINGERING SNOW SHOWERS DISSIPATE BY
FRIDAY EVENING AS PRESSURE GRADIENT REGROUPS AHEAD OF DEVELOPING
TROUGH OVR SCNTRL CANADA.
SHORTWAVE AND SFC TROUGH STAY MAINLY TO THE NORTH OF UPR LAKES FOR
THE UPCOMING WEEKEND. BEST SHOT OF LGT SNOW WILL BE OVR LK SUPERIOR
ON SATURDAY CLOSER TO THE SHORTWAVE/Q-VECTOR CONVERGENCE AND MORE
SATURATED LOW-LEVELS. A LOT OF CLOUD COVER OVER REST OF CWA ALONG
WITH BREEZY SOUTH WIND THAT WILL BRING A RETURN OF SLIGHTLY ABOVE
FREEZING TEMPS OVER MUCH OF CWA. RAN WITH CONSENSUS BEYOND SATURDAY
WITH DIFFERENCES SHOWING UP IN HOW QUICK TO BRING NEXT SHORTWAVE AND
SFC TROUGH/PRECIP INTO UPR LAKES. DOES LOOK LIKE TEMPS WILL STAY
RELATIVELY WARMER /HIGHS IN THE 30S COMPARED TO TEENS OR 20S/ BEFORE
ANOTHER PUSH OF COLDER AIR ARRIVES JUST BEYOND THE SCOPE OF THE LONG
TERM TIME RANGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1242 AM EST TUE NOV 26 2013
A WEAK HI PRES RDG/FAIRLY DRY LLVL AIR SHOWN ON THE 00Z INL RAOB WL
BRING A LULL IN THE LES EARLY THIS MRNG...WITH NO WORSE THAN MVFR
CONDITIONS PREDOMINATING EVEN WITH AN UPSLOPE WNW FLOW AT IWD AND
CMX. BUT THE PASSAGE OF A LO PRES TROF ARND SUNRISE WL LIKELY
REINTENSIFY THE SHSN AT THESE LOCATIONS AND CAUSE SOME IFR VSBYS.
ALTHOUGH ANOTHER LO PRES TROF WL TRACK THRU THE AREA IN THE EVNG...
A WSHFT TO A MORE N DIRECTION WL NOT FAVOR CMX...SO FCST MVFR
CONDITIONS HERE. ON THE OTHER HAND...THIS WSHFT WL FAVOR IWD...SO
IFR CONDITIONS SHOULD PREVAIL THERE LATE IN THE FCST PERIOD. EXPECT
VFR WX AT SAW TO PREDOMINATE INTO THIS EVNG WITH A DOWNSLOPE WIND
COMPONENT. BUT CONDITIONS THERE ARE LIKELY TO DETERIORATE QUICKLY
LATE IN THE PERIOD WITH THE WSHFT TO A FVRBL UPSLOPE N DIRECTION
FOLLOWING THE LO PRES TROF PASSAGE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 AM EST TUE NOV 26 2013
NW WINDS TO 30 KTS TODAY AS WE ARE IN THE WAKE OF COLD FRONT THAT
MOVED THROUGH MONDAY EVENING. ANOTHER TROUGH DROPS SOUTH ACROSS LK
SUPERIOR LATE TODAY AND THIS EVENING RESULTING IN WINDS SHIFTING TO
NORTH OR NORTHEAST. GALES LOOK LIKELY OVER MAINLY EAST HALF SO GALE
WARNING HAS BEEN POSTED. GALES LINGER INTO WEDNESDAY BEFORE WINDS
QUICKLY DIMINISH TO LESS THAN 20 KTS AS WEAK PRESSURE GRADIENT
DEVELOPS FOR THANKSGIVING. WINDS STAY LIGHT UNTIL SATURDAY WHEN
SOUTH WINDS INCREASE AHEAD OF LOW PRESSURE SYSTEM CROSSING SCNTRL
CANADA. WINDS MAY REACH 30 KTS OVER EASTERN SECTIONS INTO SATURDAY
EVENING. MORE LIGHT WINDS TO END THE WEEKEND AS PRESSURE GRADIENT
RELAXES AGAIN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 3 PM EST
WEDNESDAY FOR MIZ005.
LAKE EFFECT SNOW ADVISORY UNTIL NOON EST /11 AM CST/ WEDNESDAY
FOR MIZ002-009.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001-
003.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ004-
084.
LAKE EFFECT SNOW ADVISORY FROM 3 PM THIS AFTERNOON TO 3 PM EST
WEDNESDAY FOR MIZ006.
LAKE SUPERIOR...
GALE WARNING FROM 1 AM TO 1 PM EST WEDNESDAY FOR LSZ266-267.
GALE WARNING FROM 1 AM TO 10 AM EST WEDNESDAY FOR LSZ265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...KC
MARINE...JLA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
549 PM CST WED NOV 27 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 215 PM CST WED NOV 27 2013
EARLY AFTERNOON WATER VAPOR IMAGERY TOGETHER WITH GFS 27.12 HEIGHTS
AND WINDS IMMEDIATELY IDENTIFIED A LONG WAVE TROUGH ACROSS THE
EASTERN CONUS...WITH A CYCLONE DOWNSTREAM OF THIS TROUGH AXIS.
NORTHWEST FLOW PREVAILED ACROSS THE CENTRAL CONUS UPSTREAM OF THE
TROUGH AXIS. A WEAK SHORTWAVE ALONG THE ND/MN BORDER WAS EMBEDDED IN
THIS NORTHWEST FLOW. WARM AIR ADVECTION AHEAD IF THIS SHORTWAVE
TOGETHER WITH THE UPPER LEVEL DYNAMICS ASSOCIATED WITH THE 5M/HR
HEIGHT FALLS WERE THE DRIVING FORCE BEHIND AN AREA OF SNOW ACROSS
NORTHERN MINNESOTA.
THIS EVENING THE FORCING WILL WEAKEN...BUT SNOW SHOULD CONTINUE TO
SPREAD SOUTHEASTWARD INTO NORTHERN WISCONSIN. THE NORTHEASTERN
COUNTIES IN THE CWA WILL BE RIGHT ON THE EDGE OF THIS SNOW...BUT
FORECAST SOUNDINGS FOR EAU CLAIRE AND NEW RICHMOND WOULD SUPPORT AT
LEAST A FEW HOURS OF SNOW. THE LOW LEVEL DRY AIR WILL DELAY THE
ONSET UNTIL CLOSER TO 00Z THIS EVENING. SNOW TOTALS WILL BE LESS
THAN AN INCH...AND SHOULD TAPER OFF TO FLURRIES BY THURSDAY MORNING.
THE CHALLENGE FOR THURSDAYS FORECAST WAS THE CLOUD COVER. INCREASED
IT SLIGHTLY BASED OFF THE 0-1RH FROM BOTH THE NAM AND RAP WHICH SEEM
TO HAVE A GOOD HANDLE ON THE STRATUS CURRENTLY ENTERING NORTHERN
NORTH DAKOTA. ALSO LOWERED HIGH TEMPS A COUPLE OF DEGREES BECAUSE OF
THE INCREASED CLOUD COVER.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 215 PM CST WED NOV 27 2013
BIG CHGS ARE EXPECTED NEXT WEEK AS A SIGNIFICANT ARCTIC AIR MASS
SURGES SOUTHWARD ACROSS THE WESTERN CONUS...AND EVENTUALLY TAKING
HOLD OF MOST OF THE U.S...WITH THE EXCEPTION IN THE DEEP SE.
CURRENT LONG WAVE PATTERN REMAINS FROM THE NW ACROSS THE UPPER
MIDWEST ALONG WITH A SPLIT FLOW REGIME FOR THE REMAINDER OF THE
CONUS. THE SOUTHERN STREAM HAS BEEN THE MOST ACTIVE IN RECENT
WEEKS...TAKING THE BULK OF THE SIGNIFICANT WX TRACKS SOUTH AND
EAST OF THE UPPER MIDWEST. ALTHOUGH SOME TIMING AND STRENGTH
PARAMETERS REMAIN UNCLEAR IN THE DETERMINISTIC RUNS FROM BOTH THE
EC/GFS...THERE REMAINS ONE THEME...A SIGNIFICANT COLD AIR MASS
WILL INVADE MOST OF THE U.S. STARTING THIS WEEKEND IN THE PACIFIC
NW...AND EVENTUALLY THE ROCKIES/PLAINS/GREAT LAKES BY THE
FOLLOWING WEEKEND.
USUALLY MODELS ARE TOO FAST ON PATTERN CHGS...AND THIS IS EVIDENT
WITH EACH MODEL RUN. ALTHOUGH THE EC HAS BEEN THE STRONGEST ON THE
DEEP TROUGH DEVELOPING ACROSS MOST OF THE WESTERN/CENTRAL PART OF
THE U.S. BY LATE NEXT WEEK...THE ENSEMBLE MEANS /EC & GFS/ HAVE
CONTINUED TO KEEP A MORE PROGRESSIVE WX PATTERN. EVEN THE LATEST
EC 12Z/27 RUN HAS A MORE PRONOUNCED DEEP TROUGH ACROSS THE
NORTHERN ROCKIES BY THE END OF NEXT WEEK COMPARED TO THE 50H
ENSEMBLE MEAN.
BASICALLY WITH THE STRONGER AND DEEPER TROUGH...STORM SYSTEMS WILL
LIKELY BE SLOWER ON THE ONSET OF SFC LOW /BOMBS/ DEVELOPING ACROSS
THE PLAINS. OVER THE PAST 3-5 RUNS OF THE EC...THE SFC LOW AND
ASSOCIATED ARCTIC BOUNDARY KEEPS GETTING PUSHED BACK IN TIME ON
THE EVOLUTION OF A STRONG STORM SYSTEM IN THE PLAINS. THIS WILL
LIKELY KEEP OUR REGION UNEVENTFUL UNTIL LATE IN THE PERIOD...AND
POSSIBLY OUTSIDE OUR 7 DAY FORECAST IF THE TROUGH IN THE WEST
CONTINUES TO DEEPEN. IN ADDITION TO THE SLOWER PACE OF THE STORM
SYSTEM MOVING OUT INTO THE PLAINS...THE LARGE AREA OF ARCTIC HIGH
PRESSURE CIRCULATING FROM THE EASTERN CANADA...AND ACROSS THE
GREAT LAKES /EAST & NE FLOW IN THE BOUNDARY LAYER/...KEEPS OUR
REGION RELATIVELY DRY. THEREFORE...I AM NOT CONFIDENT ON ANY CHC
OF PRECIPITATION NEXT WEEK UNTIL THIS SYSTEM MOVES OUT INTO THE
PLAINS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 550 PM CST WED NOV 27 2013
AN AREA OF SNOW WILL GRAZE THE FAR EASTERN TAF AREA /KEAU/ THIS
EVENING...ALTHOUGH ATTENDANT VSBYS WOULD NOT BE EXPECTED TO LOWER
MUCH MORE THAN 4SM. SECOND ITEM OF NOTE THIS EVENING IS THE
POTENTIAL FOR MVFR LEVEL CLOUDS TO WORK INTO THE AREA ON
THANKSGIVING DAY AS A WEAK SURFACE TROUGH PASSES ACROSS THE AREA.
ATTENTION THIS EVE IS ON THE BKN-OVC DECK OF CLOUDS CIRCA 2KFT
OVER NORTHERN ND AND SRN MANITOBA. VARIOUS RH PROGS OFF THE RAP13 AND
NAM12 SOLUTIONS INDICATE THESE CLOUDS WILL INDEED HOLD TOGETHER
AND SPREAD SOUTH/EAST ACROSS THE AREA ON THURSDAY. WHILE THEY
SHOULD BE A TAD MORE TRANSPARENT DURING THE DAYTIME...A SCT-BKN
MVFR MENTION APPEARS WARRANTED IN THE TAFS AT A MINIMUM...WITH
KEAU/KRNH LIKELY SEEING BKN-OVC MVFR CIGS THROUGH A GOOD PORTION
OF THE DAY. WINDS WILL BE LIGHT AND VARIABLE TONIGHT...THEN BECOME
WEST/NORTHWEST ON THURSDAY AND INCREASE TO 10-15KTS IN THE WAKE OF
THE TROUGH.
KMSP...
MAIN CONCERN IS ABOUT THE POTENTIAL FOR MVFR CLOUDS ON THURSDAY.
IN THE MEANTIME...EXPECT MID LEVEL CLOUDS TO BE ON THE INCREASE
THIS EVE...THEN THE PRIMARY WINDOW OF POSSIBILITY FOR MVFR CIGS
WOULD BE BETWEEN 18Z THU AND 00Z FRI. HAVE INCLUDED A SCT MENTION
FOR NOW...IN EXPECTATION THAT THE MORE DENSE CLOUDS WILL LIE TO
THE NORTH/EAST. SOUTHEAST WINDS UNDER 10 KTS BECOME LIGHT AND
VARIABLE THIS EVE...THEN SHIFT TO THE NORTHWEST BY 14Z
THURSDAY /AND GUST TO AROUND 15KTS DURING THE AFTERNOON/.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS SE AT 5-10KTS.
SAT...VFR. SW WINDS AT 5-10KTS BECOMING W/NW DURING THE AFT/EVE.
SUN...VFR WITH MVFR AND -SN POSSIBLE LATE. WINDS E/SE AT 5KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...JLT
AVIATION...LS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
921 PM EST WED NOV 27 2013
.SYNOPSIS...
A STORM SYSTEM OVER NEW ENGLAND WILL CONTINUE MOVING NORTHEAST
TONIGHT. STEADY SNOW WILL END THIS EVENING, BUT LAKE EFFECT SNOW
SHOWERS WILL SET UP ACROSS UPSTATE NEW YORK TONIGHT AND CONTINUE
INTO THANKSGIVING NIGHT. HIGH PRESSURE AND DRY WEATHER WILL RETURN
FRIDAY NIGHT TO SATURDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
920 PM UPDATE...
REDUCED OVERNIGHT SNOWFALL AMOUNTS IN PROJECTED BANDS FROM AROUND
2 TO 3 INCHES, DOWN TO 1.5 TO 2 INCHES. THIS IS MOSTLY FROM A
REDUCTION IN THE FIRST 6 HOURS, AS BAND INTO SYR AREA HAS NOT YET
SHOWN SIGNS OF FORMING. LATEST HRRR HAS A PRETTY GOOD HANDLE ON
THE RADAR DEPICTION, AND IT KEEPS THE RETURNS PRETTY LIGHT THROUGH
THE NEXT FEW HOURS.
STILL ANTICIPATE BAND INTENSIFICATION SOMETIME BETWEEN 7Z AND 9Z,
WITH MOST OF THE OVERNIGHT SNOW ACCUMULATION COMING IN THE FINAL 6
HOURS OF THE OVERNIGHT PERIOD.
515 PM UPDATE...
QUICK UPDATE TO LOWER POPS TO SLIGHT CHANCE OVER NY COUNTIES WEST
OF I-81 IN LOWER DEWPOINT ATMOSPHERE. BACK EDGE OF SYNOPTIC SNOW IS ALONG
THE I-81 CORRIDOR EASTWARD. WESTWARD - JUST A FEW RADAR RETURNS
AND MAJORITY OF OBS ARE REPORTING DRY WEATHER. AS THE EVENING
WEARS ON...THE EVENT WILL TRANSITION TO LAKE EFFECT OVER NORTHERN
FA.
3 PM UPDATE...
BACK EDGE OF SYNOPTIC PRECIP STILL IN NE PA AND THE CATSKILLS.
RAIN HAS NOW MOSTLY CHANGED TO SNOW. THIS WILL LIFT NE BY 6 PM AS
THE LARGE SFC LOW IN EASTERN NEW ENGLAND. NW FLOW ACROSS THE
ENTIRE CWA WITH WEAK LAKE EFFECT STARTING. AS THE LOW LEVEL FLOW
ALIGNS AND COLDER AIR COMES IN THE LAKE EFFECT SNOW WILL EXPAND IN
COVERAGE AND INCREASE IN INTENSITY. WITH A 320 FLOW IT WILL BE
MULTIBANDS. GEORGIAN BAY CONNECTION COMES INTO PLAY AS THE FLOW
SHIFTS SOME TO WNW. MOISTURE DEPTH OF 10KT. DENDRITE ZONE OF 2K FT
STARTS AROUND 6K THEN DROPS TO 4K LATE TONIGHT. GOOD LIFT THROUGH
THE MOISTURE AND DENDRITE ZONES. ISSUED A LES ADVISORY FOR
ONONDAGA ONEIDA MADISON FOR TONIGHT TO THU NGT.
OUTSIDE OF THE LAKE EFFECT IN CENTRAL NY...NE PA WILL BE CLOUDY
AND MOSTLY DRY. CAA IS STRONG WITH TEMPS FALLING UPPER TEENS AND
L20S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
3 PM UPDATE...
THU MORNING A LULL BEFORE A SHORT WAVE DROPS SE HELPING TO ENHANCE
THE LAKE EFFECT. LOW LEVEL FLOW SHIFTS TO 290 BRINGING THE BEST
BAND INTO SYRACUSE AND ONEIDA AND CAZENOVIA. THIS BAND WILL
CONTINUE INTO THE EVENING BEFORE WEAKENING LATE THU NGT. MULTILAKE
CONNECTION FROM GEORGIAN BAY. COULD BE A GOOD ENOUGH BAND FOR
HALF AN INCH TO AN INCH AN HOUR SNOW. HEAVIEST SNOW TOTALS THU PM
3 TO 5 INCHES.
FRIDAY COLD NW LOW LEVEL FLOW STILL GOING AS A LARGE DRY CANADIAN
HIGH PRESSURE MOVES IN FROM THE NW. LL FLOW BECOMES LIGHT AND IS
SHEARED SO SNOW ACCUMULATIONS WILL BE LESS THAN 2 INCHES
EVERYWHERE BEFORE LES SHUTS DOWN FRI AFTN. HIGH OVER THE CWA FRI
NGT AND STALLS INTO SAT NGT. WAA AT 850MB KICKS IN WHILE UPPER
LEVEL HEIGHTS RISE. SFC TEMPS STILL BELOW NORMAL AND MOSTLY BELOW
FREEZING.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
PD BEGINS WITH A WEAK WV DROPPING THRU THE GREAT LAKES. DFRNCS
BETWEEN THE EURO AND GFS WILL HAVE LTL EFFECT ON THE SENSIBLE WX
FOR THE SYSTEM WHICH LOOKS TO GENERATE SOME LGT PCPNSAT NGT INTO
SUNDAY. TEMPS MRGNL...BUT LOOKS COLD ENUF FOR SOME LGT SNOW MOST
PLACE...ESP NORTH. SLGTLY MILDER OVER NEPA BUT WITH A LWR CHANCE
PF PCPN IT MAY NOT MAKE MUCH DFRNC. SYSTEM, PASSES THRU SUN BUT
LEAVES THE AREA IN A SHALLOW UT BROAD UPR TROF OVER THE
LAKES...AND WEAK AREA OF MOISTURE PCPN. EURO SUGGESTS SOME WEAK
CSTL DVLPMT ON TUE PERHAPS ORGANIZING THE PCPN A BIT MORE. GFS HAS
DVLPMT FURTHER OUT TO SEA BUT STILL SOME ENHANCED PCPN OVER THE
ERN ZONES. HWVR...IN GNRL JUST A SEASONABLY COOL PD WITH LGT PCPN
AT TIMES.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
AT 00Z, A BRIEF BAND OF HEAVIER SNOW WAS PASSING THROUGH THE AREA
AND IT WILL AFFECT THE KRME TAF THROUGH 01Z WITH IFR SNOW
SHOWERS. A BRISK NORTHWEST FLOW WILL PREVAIL ACROSS THE AREA
THROUGH THIS TAF PERIOD WITH WIDESPREAD MVFR CIGS AND FLURRIES
EXPECTED AT ALL TERMINALS EXCEPT FOR KELM/KAVP WHERE CONDITIONS WILL
BE PRIMARILY VFR.
AT KSYR, A LAKE EFFECT SNOWBAND WILL DEVELOP LATER THIS EVENING AND
BRING CONDITIONS TO IFR BEGINNING AROUND 03Z AND CONTINUING UNTIL
18Z WHEN CONDITIONS MAY IMPROVE TO MVFR AS THE BAND LIFTS NORTH OF
THE AIRPORT. THE HEAVIEST SNOW MAY OCCUR BETWEEN 08Z-12Z AND
THEREFORE INCLUDED BELOW ALT MIN CONDITIONS HERE.
NORTHWEST WINDS 10-15 KNOTS WITH GUSTS AROUND 25 KNOTS DIMINISHING
TO 10-12 KNOTS BY MID MORNING THURSDAY.
OUTLOOK...
THU NIGHT TO SUN MORN...MAINLY VFR.
SUN AFTN TO MON...MVFR AND MAYBE IFR IN MIXED PRECIP.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST FRIDAY FOR NYZ009-018-
036-037.
&&
$$
SYNOPSIS...TAC
NEAR TERM...DJP/TAC
SHORT TERM...TAC
LONG TERM...DGM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS RALEIGH NC
648 AM EST TUE NOV 26 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM OVER THE NORTHERN GULF OF MEXICO
WILL RAPIDLY INTENSIFY AS IT LIFTS NORTHEASTWARD THROUGH THE
CAROLINAS AND MIDDLE ATLANTIC STATES TODAY AND TONIGHT. ARCTIC HIGH
PRESSURE WILL BUILD EAST OF THE APPALACHIANS WEDNESDAY AND WEDNESDAY
NIGHT...THEN LINGER THROUGH THE END OF THE WEEK.
&&
UPDATED TO ADD GRANVILLE...VANCE...AND STANLY COUNTIES TO THE
WINTER WEATHER ADVISORY.
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM TUESDAY...
PRECIPITATION HAS BEEN A LITTLE SLOWER THAN EXPECTED TO SPREAD IN TO
CENTRAL NC THIS MORNING...WITH ONLY KINT HAVING REPORTED A LITTLE
MIX OF SLEET AND RAIN THUS FAR. ISENTROPIC UPGLIDE DRIVEN BY A
STRENGTHENING AND EASTWARD-EXPANDING H85 LLJ OF 35-40 KTS WILL
NONETHELESS SUPPORT FURTHER LIFT AND MOISTENING TO ALLOW INCREASING
RADAR RETURNS PER KGSP RADAR TO OVERSPREAD THE NORTHWEST PIEDMONT
BETWEEN 5 AND 8 AM...PER RECENT RUNS OF THE HRRR AND RAP. THE
SPECIAL RELEASE 06Z KGSO RAOB INDICATED THIS MOISTENING PROCESS WAS
WELL UNDERWAY...WITH JUST A COUPLE OF SHALLOW...BUT STOUT DRY LAYERS
AROUND 10 THOUSAND...AND THE LOWEST 3 THOUSAND...FT REMAINING. THE
FORECAST WET BULB FREEZING LINE IS STILL FORECAST TO RETREAT ACROSS
THE PIEDMONT THROUGH 10-11 AM...A LITTLE MORE SLOWLY THAN EARLIER
PROGGED...AND STILL PROBABLY LINGERING OVER FORSYTH AND PERSON
COUNTIES UNTIL AROUND NOON OR SO. IT WILL TAKE SOME TIME FOR THE
PRECIPITATION TO EDGE INTO THE TRIANGLE - BETWEEN 8-11 AM - AND THE
COASTAL PLAIN DURING THE MIDDAY HOURS. THERE WILL CONSEQUENTLY BE
LITTLE OPPORTUNITY FOR ANYTHING BUT A CHILLY RAIN IN THOSE AREAS...
WITH THE EXCEPTION OF THE FAR NORTHERN REACHES OF NORTHERN DURHAM
COUNTY FOR AN HOUR OR TWO. THE PRECIPITATION AMOUNTS DURING THAT
TIME WILL BE SO LIGHT THAT ANY VERY LIGHT FREEZING RAIN WOULD HAVE
LITTLE TO NO IMPACT. THE BETTER CHANCE OF SEEING SEVERAL
HUNDREDTHS...TO AROUND A TENTH OF AN INCH OVER THE FAR NW
PIEDMONT...WILL OCCUR IN THE CURRENT ADVISORY AREA.
THE OTHER NOTABLE TREND IN GUIDANCE HAS BEEN FOR A MORE INLAND TRACK
OF THE SURFACE LOW TAKING SHAPE OVER THE NORTHERN GULF OF MEXICO...
AND ANOTHER PRECEDING LOW FORECAST TO DEVELOP OVER NC AND VA THIS
EVENING...AS THE FORCING FOR ASCENT ATTENDANT THE NORTHERN STREAM
OVERSPREADS THE LOW LEVEL FRONTAL ZONE. WHILE IT IS STILL LIKELY THE
MODELS ARE TOO AGGRESSIVE ERADICATING THE WEDGE AND BARRELING THE
WARM SECTOR ALL THE WAY INTO THE TRIAD THIS EVENING...IT IS HARD
TO IGNORE THIS MORE INLAND TREND EVEN IN THE HI-RES NMM AND ARW
CORES THAT TEND TO BETTER RESOLVE AND RESPECT CAD. EVEN THEY DRIVE
THE FRONTAL ZONE TO NEAR OR JUST EAST OF HWY 1...AND THIS SOLUTION
SEEMS ACCEPTABLE. BIG TEMPERATURE BUSTS REMAIN LIKELY INVOF THE
FRONT...WHICH WILL LIKELY BE CHARACTERIZED BY A 25-30 DEGREE
TEMPERATURE GRADIENT ACROSS SINGLE COUNTIES...WITH 30S IN THE
RESIDUAL IN-SITU WEDGE OVER THE WESTERN PIEDMONT...AND 60S IN THE
WARM SECTOR. TEMPERATURES WILL CHANGE LITTLE OVERNIGHT...WITH SOME
GRADUAL RISES INTO THE 60S IN THE WARM SECTOR THE MOST LIKELY
CHANGE FROM AFTERNOON TEMPS.
THE MORE INLAND WARM SECTOR PENETRATION ALSO RAISES CONCERN FOR
THE POTENTIAL FOR STRONG TO SEVERE CONVECTION...GIVEN THE EXTREME
LOW AND DEEP SHEAR PROFILES ATTENDING THE RAPIDLY DEEPENING LOW
PRESSURE SYSTEM AND INCREASINGLY-PHASED AND NEGATIVELY-TILTED
TROUGH AXES ALOFT. THIS THREAT WOULD BE HIGHEST OVER THE COASTAL
PLAIN AND FAR EASTERN SANDHILLS AND PIEDMONT AS THE NOSE OF THE
LLJ ACCELERATES ACROSS EAST-CENTRAL NC AND SUPPORTS SCATTERED
SURFACE-BASED...OR NEARLY SO...CONVECTION BETWEEN 7 PM AND 2 AM.
FORECAST BUFR SOUNDINGS SUGGEST CONVECTION OF THE ELEVATED
VARIETY COULD OCCUR IN THE CAD REGIME AS WELL...WITH UP TO A FEW
HUNDRED J/KG OF MUCAPE INDICATED ACROSS ALL OF CENTRAL NC FOR
SEVERAL HOURS THIS EVENING-EARLY TONIGHT. A MID LEVEL DRY SLOT MAY
LARGELY END PRECIPITATION FOR A TIME OVERNIGHT...AFTER THE RAIN
BECOMES HEAVY AT TIMES DURING THE AFTERNOON AND EVENING HOURS. THE
BULK OF THE PREVIOUSLY FORECAST ONE TO TWO INCHES OF SOAKING RAIN
(WELL BELOW FLASH FLOOD GUIDANCE)... HIGHEST WEST...WILL HAVE
FALLEN BY THAT TIME. THE LEADING EDGE OF CONCENTRATED DCVA
ATTENDING THE POTENT SOUTHERN STREAM SHORTWAVE TROUGH OVER WEST TX
SHOULD THEN RESULT IN THE REDEVELOPMENT OF RAIN...PERHAPS IN THE
FORM OF A BAND OF SHALLOW ELEVATED CONVECTION...LATE TONIGHT INTO
EARLY WEDNESDAY. AREAS OF FOG... INCLUDING SOME DENSE OVER THE
WESTERN PIEDMONT...WILL ALSO BE PROBABLE ON THE COOL SIDE OF THE
BOUNDARY TONIGHT.
&&
.SHORT TERM /WEDNESDAY/...
AS OF 345 AM TUESDAY...
GUIDANCE REMAINS CONSISTENT THAT THE DEPTH OF THE SATURATED LAYER
WILL STRUGGLE TO REACH THE MINUS 10 LEVEL...AS THE STRONGEST HEIGHT
FALLS/DYNAMICS ALOFT PIVOT NORTHEASTWARD. THE EXCEPTION WILL BE OVER
THE WESTERN AND NORTHERN PIEDMONT...WHERE BRIEF DEEPENING TO NEAR
MINUS 12...IN BAND OF LAST GASP DEFORMATION PRECIPITATION...IS
FORECAST TO OCCUR IN THE SEVERAL HOURS CENTERED AROUND 18Z. A FEW
WET FLAKES MAY CONSEQUENTLY MIX WITH THE RAIN AS THE PRECIPITATION
COMES TO AND END DURING THE AFTERNOON. AREAS OUTSIDE OF THE
DEFORMATION BAND...NAMELY OVER THE COASTAL COLAN AND PERHAPS
SANDHILLS...WILL LIKELY RECEIVE LITTLE TO NO ADDITIONAL RAIN...WITH
JUST A PARTLY CLOUDY SKY IN THE DRY SLOT. ALL AREAS WILL
EXPERIENCE STRONG CAA...HOWEVER...WITH TEMPERATURES TUMBLING INTO
THE 40S... AND 30S OVER THE WESTERN PIEDMONT...DURING THE LATE
MORNING TO EARLY AFTERNOON HOURS. BLUSTERY NW WINDS WILL ALSO GUST
TO BETWEEN 30 AND 35 MPH AS THE FRESH ARCTIC AIR MASS SURGES
ACROSS THE STATE BEHIND THE RAPIDLY DEEPENING LOW BOUND FOR NEW
ENGLAND AND EASTERN CANADA...WHICH WILL YIELD WIND CHILL VALUES
ABOUT 15 DEGREES COOLER THAN THE AFOREMENTIONED AIR TEMPS IN THE
30S-40S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
AS OF 250 AM TUESDAY...
WEDNESDAY NIGHT THROUGH SUNDAY: AS THE COLD FRONT MOVES FARTHER OFF
THE CAROLINA COAST AND THE LOW MOVES NE AWAY FROM THE AREA...SKIES
WILL BEGIN TO CLEAR AND LOW TEMPS FOR WEDNESDAY NIGHT WILL DROP INTO
THE LOW 20S NW TO UPPER 20S EAST. WINDS WILL REMAIN BREEZY OVERNIGHT
UNTIL THE PRESSURE GRADIENT RELAXES AND SURFACE HIGH PRESSURE MOVES
OVER THE APPALACHIANS ON THURSDAY. WITH THE COLD HIGH PRESSURE IN
PLACE...EXPECT HIGHS ON THURSDAY IN THE UPPER 30S TO LOW 40 AND
OVERNIGHT LOWS SIMILAR TO THE PREVIOUS NIGHT...LOW TO UPPER 20S. THE
SURFACE HIGH SHOULD MIGRATE OVER THE GREAT LAKES AND INTO THE
NORTHEAST BY FRIDAY WITH THE RIDGE EXTENDING SOUTHWEST INTO CENTRAL
NC WHERE IT WILL REMAIN THROUGH SUNDAY. THE RESULT WILL BE A DRY
FORECAST...MAINLY CLEAR SKIES AND COLD TEMPERATURES...WITH HIGHS
FRIDAY IN THE MID TO UPPER 40S. HIGHS SATURDAY AND SUNDAY WILL BE
DEPENDENT ON THE EASTWARD EXTENT OF THE WEDGE...BUT FOR NOW EXPECT
GRADUALLY INCREASING HIGHS IN THE EAST INTO THE MID 50S BY SUNDAY...
AND A SLOWER INCREASE IN THE NW...UPPER 40S SUNDAY. EXPECT A SIMILAR
TREND IN OVERNIGHT LOWS...MID 20S TO NEAR 30 DEGREES FRIDAY NIGHT
INCREASING SLIGHTLY INTO THE MID 20S TO LOW 30S FOR SATURDAY NIGHT.
SUNDAY NIGHT THROUGH MONDAY NIGHT: THERE ARE DIFFERENCES BETWEEN THE
MODELS WITH RESPECT TO UPPER LEVEL TROUGH AND PRECIP DEVELOPMENT FOR
THIS PART OF THE FORECAST...BUT THEY INDICATE THE RIDGE WEAKENING
AND CLOUD COVER INCREASING SUNDAY NIGHT AND MONDAY. EXPECT THE
COLUMN TO MOISTEN AND CHANCES FOR PRECIP TO INCREASE...HOWEVER
NAILING DOWN ANY TIMING IS DIFFICULT AT THIS TIME. FOR NOW WILL
GRADUALLY INCREASE PRECIP CHANCES SUNDAY NIGHT THROUGH MONDAY NIGHT.
SHOULD SEE HIGH TEMPS MODERATE A BIT...MID 50S TO LOW 60S FOR
MONDAY. OVERNIGHT LOWS GENERALLY IN THE MID 30S TO LOW 40S.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 645 AM TUESDAY...
24 HOUR TAF PERIOD: FREEZING RAIN HAS BEEN REPORTED THIS HOUR AT
KGSO WITH UNKNOWN PRECIPITATION OCCURRING AT KINT. TEMPERATURES IN
BOTH LOCATIONS ARE AT 32 DEGREES AND EXPECTED TO REMAIN THERE FOR
THE NEXT COUPLE OF HOURS. RADAR SHOWS STEADY LIGHT RAIN OVER THE
TRIAD BUT PERHAPS A BREAK IN THE RAIN COMING UP IN THE NEXT HOUR.
AFTER 14Z EXPECT TEMPERATURES TO RISE BACK ABOVE FREEZING AND
MODERATE RAIN WILL BE THE MAIN FORM OF PRECIPITATION FOR THE REST OF
THE DAY. TO THE EAST NO THREAT OF FREEZING RAIN BUT MODERATE RAIN
EXPECTED LATER TODAY.
A GRAB BAG OF AVIATION CONDITIONS OUT THERE THIS MORNING WITH SOME
IFR CEILINGS IN THE SOUTH...MAINLY MVFR IN THE NORTHWEST AND VFR
HANGING ON IN THE EAST BUT NOT FOR LONG AS THEY WILL DIP TO MVFR
AFTER THE ONSET OF PRECIPITATION LATER THIS MORNING.
WINDS TO DAY WILL BE MAINLY NORTHEASTERLY NEAR 10 KNOTS WITH FASTER
WIND SPEEDS IN THE SOUTHEAST. LATER TODAY AS THE LOW APPROACHES
WINDS IN THE NORTHWEST WILL BE NORTHWESTERLY AND WINDS IN THE EAST
WILL BE MORE SOUTHEASTERLY. OFF THE DECK...LOW LEVEL WIND SHEAR WILL
BE A CONCERN NEAR THE 2000 FT LEVEL WITH 35-40 KNOT SOUTHEASTERLY
SHEAR. THE GREATEST CONCERN FOR LLWS WILL BE IN THE TRIAD CONTINUING
THROUGH TODAY TO THE EARLY MORNING HOURS WEDNESDAY. LIKELIHOOD OF
LLWS DECREASES FOR EASTERN TERMINAL BUT WILL STILL BE PRESENT AT
LEAST THROUGH TUESDAY AFTERNOON/EARLY EVENING.
LONG TERM: RAIN WITH THIS SYSTEM WILL CONTINUE INTO WEDNESDAY AND
WIND SPEEDS ARE EXPECTED TO INCREASE WEDNESDAY AFTERNOON WITH GUSTS
UP TO 30 MPH POSSIBLE. THURSDAY THROUGH THE END OF THE WEEK SHOULD
SEE A RETURN TO VFR CONDITIONS UNTIL THE NEXT STORM SYSTEM
APPROACHES EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NCZ007-
021>024-038-039.
WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR
NCZ008-009-073.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...MWS
LONG TERM...KC
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
354 AM EST TUE NOV 26 2013
.SYNOPSIS...A LOW PRESSURE SYSTEM OVER THE NORTHERN GULF OF MEXICO
WILL RAPIDLY INTENSIFY AS IT LIFTS NORTHEASTWARD THROUGH THE
CAROLINAS AND MIDDLE ATLANTIC STATES TODAY AND TONIGHT. ARCTIC HIGH
PRESSURE WILL BUILD EAST OF THE APPALACHIANS WEDNESDAY AND WEDNESDAY
NIGHT...THEN LINGER THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM TUESDAY...
PRECIPITATION HAS BEEN A LITTLE SLOWER THAN EXPECTED TO SPREAD IN TO
CENTRAL NC THIS MORNING...WITH ONLY KINT HAVING REPORTED A LITTLE
MIX OF SLEET AND RAIN THUS FAR. ISENTROPIC UPGLIDE DRIVEN BY A
STRENGHTNEING AND EASTWARD-EXPANDING H85 LLJ OF 35-40 KTS WILL
NONETHELESS SUPPORT FURTHER LIFT AND MOISTENING TO ALLOW INCREASING
RADAR RETURNS PER KGSP RADAR TO OVERSPREAD THE NORTHWEST PIEDMONT
BETWEEN 5 AND 8 AM...PER RECENT RUNS OF THE HRRR AND RAP. THE
SPECIAL RELEASE 06Z KGSO RAOB INDICATED THIS MOISTENING PROCESS WAS
WELL UNDERWAY...WITH JUST A COUPLE OF SHALLOW...BUT STOUT DRY LAYERS
AROUND 10 THOUSAND...AND THE LOWEST 3 THOUSAND...FT REMAINING. THE
FORECAST WET BULB FREEZING LINE IS STILL FORECAST TO RETREAT ACROSS
THE PIEDMONT THROUGH 10-11 AM...A LITTLE MORE SLOWLY THAN EARLIER
PROGGED...AND STILL PROBABLY LINGERING OVER FORSYTH AND PERSON
COUNTIES UNTIL AROUND NOON OR SO. IT WILL TAKE SOME TIME FOR THE
PRECIPITATION TO EDGE INTO THE TRIANGLE - BETWEEN 8-11 AM - AND THE
COASTAL PLAIN DURING THE MIDDAY HOURS. THERE WILL CONSEQUENTLY BE
LITTLE OPPORTUNITY FOR ANYTHING BUT A CHILLY RAIN IN THOSE AREAS...
WITH THE EXCEPTION OF THE FAR NORTHERN REACHES OF NORTHERN DURHAM
COUNTY FOR AN HOUR OR TWO. THE PRECIPITATION AMOUNTS DURING THAT
TIME WILL BE SO LIGHT THAT ANY VERY LIGHT FREEZING RAIN WOULD HAVE
LITTLE TO NO IMPACT. THE BETTER CHANCE OF SEEING SEVERAL
HUNDREDTHS...TO AROUND A TENTH OF AN INCH OVER THE FAR NW
PIEDMONT...WILL OCCUR IN THE CURRENT ADVISORY AREA.
THE OTHER NOTABLE TREND IN GUIDANCE HAS BEEN FOR A MORE INLAND TRACK
OF THE SURFACE LOW TAKING SHAPE OVER THE NORTHERN GULF OF MEXICO...
AND ANOTHER PRECEDING LOW FORECAST TO DEVELOP OVER NC AND VA THIS
EVENING...AS THE FORCING FOR ASCENT ATTENDANT THE NORTHERN STREAM
OVERSPREADS THE LOW LEVEL FRONTAL ZONE. WHILE IT IS STILL LIKELY THE
MODELS ARE TOO AGGRESIVE ERRADICATING THE WEDGE AND BAREELING THE
WARM SECTOR ALL THE WAY INTO THE TRIAD THIS EVENING...IT IS HARD TO
IGNORE THIS MORE INLAND TREND EVEN IN THE HI-RES NMM AND ARW CORES
THAT TEND TO BETTER RESOLVE AND RESPECT CAD. EVEN THEY DRIVE THE
FRONTAL ZONE TO NEAR OR JUST EAST OF HWY 1...AND THIS SOLUTION SEEMS
ACCEPTABLE. BIG TEMPERATURE BUSTS REMAIN LIKELY INVOF THE
FRONT...WHICH WILL LIKELY BE CHARACTERIZED BY A 25-30 DEGREE
TEMPERATURE GRADIENT ACROSS SINGLE COUNTIES...WITH 30S IN THE
RESIUDAL IN-SITU WEDGE OVER THE WESTERN PIEDMONT...AND 60S IN THE
WARM SECTOR. TEMPERATURES WILL CHANGE LITTLE OVERNIGHT...WITH SOME
GRADUAL RISES INTO THE 60S IN THE WARM SECTOR THE MOST LIKELY CHANGE
FROM AFTERNOON TEMPS.
THE MORE INLAND WARM SECTOR PENERTATION ALSO RAISES CONCERN FOR THE
POTENTIAL FOR STRONG TO SEVERE CONVECTION...GIVEN THE EXTREME LOW
AND DEEP SHEAR PROFILES ATTENDING THE RAPIDLY DEEPENING LOW PRESSURE
SYSTEM AND INCREASINGLY-PHASED AND NEGATIVELY-TILTED TROUGH AXES
ALOFT. THIS THREAT WOULD BE HIGHEST OVER THE COASTAL PLAIN AND FAR
EASTERN SANDHILLS AND PIEDMONT AS THE NOSE OF THE LLJ ACCELERATES
ACROSS EAST-CENTRAL NC AND SUPPORTS SCATTERED SURFACE-BASED...OR
NEARLY SO...CONVECTION BETWEEN 7 PM AND 2 AM. FORECST BUFR SOUNDINGS
SUGGEST CONVECTION OF THE ELEVATED VARIETY COULD OCCUR IN THE CAD
REGIME AS WELL...WITH UP TO A FEW HUNDRED J/KG OF MUCAPE INDICATED
ACROSS ALL OF CENTRAL NC FOR SEVERAL HOURS THIS EVENING-EARLY
TONIGHT. A MID LEVEL DRY SLOT MAY LARGELY END PRECIPITATION FOR A
TIME OVERNIGHT...AFTER THE RAIN BECOMES HEAVY AT TIMES DURING THE
AFTERNOON AND EVENING HOURS. THE BULK OF THE PREVIOUSLY FORECAST ONE
TO TWO INCHES OF SOAKING RAIN (WELL BELOW FLASH FLOOD GUIDANCE)...
HIGHEST WEST...WILL HAVE FALLEN BY THAT TIME. THE LEADING EDGE OF
CONCENTRATED DCVA ATTENDING THE POTENT SOUTHERN STREAM SHORTWAVE
TROUGH OVER WEST TX SHOULD THEN RESULT IN THE REDEVELOPMENT OF
RAIN...PERHAPS IN THE FORM OF A BAND OF SHALLOW ELEVATED
CONVECTION...LATE TONIGHT INTO EARLY WEDNESDAY. AREAS OF FOG...
INCLUDING SOME DENSE OVER THE WESTERN PIEDMONT...WILL ALSO BE
PROBABLE ON THE COOL SIDE OF THE BOUNDARY TONIGHT.
&&
.SHORT TERM /WEDNESDAY/...
AS OF 345 AM TUESDAY...
GUIDANCE REMAINS CONSISTENT THAT THE DEPTH OF THE SATURATED LAYER
WILL STRUGGLE TO REACH THE MINUS 10 LEVEL...AS THE STRONGEST HEIGHT
FALLS/DYNAMICS ALOFT PIVOT NORTHEASTWARD. THE EXCEPTION WILL BE OVER
THE WESTERN AND NORTHERN PIEDMONT...WHERE BRIEF DEEPENING TO NEAR
MINUS 12...IN BAND OF LAST GASP DEFORMATION PRECIPITATION...IS
FORECAST TO OCCUR IN THE SEVERAL HOURS CENTERED AROUND 18Z. A FEW
WET FLAKES MAY CONSEQUENTLY MIX WITH THE RAIN AS THE PRECIPITATION
COMES TO AND END DURING THE AFTERNOON. AREAS OUTSIDE OF THE
DEFORMATION BAND...NAMELY OVER THE COASTAL COLAN AND PERHAPS
SANDHILLS...WILL LIKELY RECEIVE LITTLE TO NO ADDIITIONAL RAIN...WITH
JUST A PARTLY CLOUDY SKY IN THE DRY SLOT. ALL AREAS WILL EXPERIENCE
STRONG CAA...HOWVEER...WITH TEMPERATURES TUMBLING INTO THE 40S...
AND 30S OVER THE WESTERN PIEDMONT...DURING THE LATE MORNING TO EARLY
AFTERNOON HOURS. BLUSTERY NW WINDS WILL ALSO GUST TO BETWEEN 30 AND
35 MPH AS THE FRESH ARCTIC AIR MASS SURGES ACROSS THE STATE BEHIND
THE RAPIDLY DEPEENING LOW BOUND FOR NEW ENGLAND AND EASTERN
CANADA...WHICH WILL YIELD WIND CHILL VALUES ABOUT 15 DEGREES COOLER
THAN THE AFORMENTIONED AIR TEMPS IN THE 30S-40S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
AS OF 250 AM TUESDAY...
WEDNESDAY NIGHT THROUGH SUNDAY: AS THE COLD FRONT MOVES FARTHER OFF
THE CAROLINA COAST AND THE LOW MOVES NE AWAY FROM THE AREA...SKIES
WILL BEGIN TO CLEAR AND LOW TEMPS FOR WEDNESDAY NIGHT WILL DROP INTO
THE LOW 20S NW TO UPPER 20S EAST. WINDS WILL REMAIN BREEZY OVERNIGHT
UNTIL THE PRESSURE GRADIENT RELAXES AND SURFACE HIGH PRESSURE MOVES
OVER THE APPALACHIANS ON THURSDAY. WITH THE COLD HIGH PRESSURE IN
PLACE...EXPECT HIGHS ON THURSDAY IN THE UPPER 30S TO LOW 40 AND
OVERNIGHT LOWS SIMILAR TO THE PREVIOUS NIGHT...LOW TO UPPER 20S. THE
SURFACE HIGH SHOULD MIGRATE OVER THE GREAT LAKES AND INTO THE
NORTHEAST BY FRIDAY WITH THE RIDGE EXTENDING SOUTHWEST INTO CENTRAL
NC WHERE IT WILL REMAIN THROUGH SUNDAY. THE RESULT WILL BE A DRY
FORECAST...MAINLY CLEAR SKIES AND COLD TEMPERATURES...WITH HIGHS
FRIDAY IN THE MID TO UPPER 40S. HIGHS SATURDAY AND SUNDAY WILL BE
DEPENDENT ON THE EASTWARD EXTENT OF THE WEDGE...BUT FOR NOW EXPECT
GRADUALLY INCREASING HIGHS IN THE EAST INTO THE MID 50S BY SUNDAY...
AND A SLOWER INCREASE IN THE NW...UPPER 40S SUNDAY. EXPECT A SIMILAR
TREND IN OVERNIGHT LOWS...MID 20S TO NEAR 30 DEGREES FRIDAY NIGHT
INCREASING SLIGHTLY INTO THE MID 20S TO LOW 30S FOR SATURDAY NIGHT.
SUNDAY NIGHT THROUGH MONDAY NIGHT: THERE ARE DIFFERENCES BETWEEN THE
MODELS WITH RESPECT TO UPPER LEVEL TROUGH AND PRECIP DEVELOPMENT FOR
THIS PART OF THE FORECAST...BUT THEY INDICATE THE RIDGE WEAKENING
AND CLOUD COVER INCREASING SUNDAY NIGHT AND MONDAY. EXPECT THE
COLUMN TO MOISTEN AND CHANCES FOR PRECIP TO INCREASE...HOWEVER
NAILING DOWN ANY TIMING IS DIFFICULT AT THIS TIME. FOR NOW WILL
GRADUALLY INCREASE PRECIP CHANCES SUNDAY NIGHT THROUGH MONDAY NIGHT.
SHOULD SEE HIGH TEMPS MODERATE A BIT...MID 50S TO LOW 60S FOR
MONDAY. OVERNIGHT LOWS GENERALLY IN THE MID 30S TO LOW 40S.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 115 AM TUESDAY...
24 HOUR TAF PERIOD:
THE MOST TREACHEROUS CONDITIONS FOR THE TAFS WILL BE IN THE TRIAD AS
A POTENT STORM SYSTEM MOVES IN FROM THE SOUTHWEST. NO RAIN OBSERVED
YET AT KINT AND KGSO DESPITE RADAR RETURNS ON THE 0.5 DEGREE
ELEVATION ANGLE. THIS IS OWING TO VERY DRY AIR IN THE LOWER LEVELS
WHICH WILL TAKE A WHILE TO OVERCOME BEFORE PRECIPITATION BEGINS IN
THE TRIAD. AS EVAPORATIVE COOLING OCCURS IN THE LOW LEVELS
TEMPERATURES WILL COOL TO NEAR FREEZING AND A PERIOD OF FREEZING
RAIN IS POSSIBLE AT KINT AND KGSO BEGINNING AROUND 9Z THROUGH 14Z OR
SO BEFORE WARM AIR ADVECTION CAUSES TEMPERATURES TO RECOVER. AT THIS
TIME FREEZING RAIN IS EXPECTED TO GIVE WAY TO AN EXTENDED PERIOD OF
LIGHT TO MODERATE RAIN...WITH POCKETS OF HEAVIER PRECIPITATION
THROUGH THE END OF THE TAF PERIOD. ALREADY MVFR CONDITIONS IN THE
TRIAD ARE EXPECTED TO FURTHER DETERIORATE TO IFR/LIFR AND MOST
LIKELY WILL REMAIN IN THE TANK THROUGH THE PERIOD WITH CEILINGS LESS
THAN 1000 FEET AND VISIBILITIES MAINLY IN THE MVFR RANGE.
CONDITIONS AT THE REMAINING TAF SITES WILL BE SIMILAR BUT WITHOUT
THE PERIOD OF FREEZING RAIN AT THE ONSET AS TEMPERATURES ARE
EXPECTED TO REMAIN ABOVE FREEZING THROUGH THE PERIOD. ANOTHER
CONCERN AT ALL TAF LOCATIONS WILL BE LOW LEVEL WIND SHEAR THAT IS
EXPECTED TO PICK UP JUST AFTER SUNRISE...NEAR 14Z. LIGHT EAST OR
NORTHEASTERLY WINDS IN THE LOW LEVELS WILL RAPIDLY INCREASE TO 35 TO
40 KNOTS OUT OF THE SOUTHEAST NEAR 2 KFT. WHILE THE SEVERITY OF THE
LLWS WILL DECREASE AFTER 00Z WEDNESDAY...LLWS WILL STILL BE A
CONCERN THROUGH THE END OF THE TAF PERIOD WITH THE EXCEPTION OF KRWI
WHERE THE THREAT WILL END EARLIER AS SURFACE WINDS SHOULD BE
STRONGER AND NEAR UNIDIRECTIONAL TO HELP MITIGATE SHEAR POTENTIAL.
LONG TERM: A SECOND STORM SYSTEM WILL FOLLOW RIGHT BEHIND THE FIRST
WHICH WILL CARRY INTO WEDNESDAY BEFORE CLEARING OUT WEDNESDAY NIGHT.
CONDITIONS SHOULD BE PREDOMINATELY VFR THEREAFTER UNTIL EARLY NEXT
WEEK WHEN THE NEXT SYSTEM APPROACHES.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR NCZ007-
021>024-038-039.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...MWS
LONG TERM...KC
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
335 AM EST TUE NOV 26 2013
.SYNOPSIS...A LOW PRESSURE SYSTEM OVER THE NORTHERN GULF OF MEXICO
WILL RAPIDLY INTENSIFY AS IT LIFTS NORTHEASTWARD THROUGH THE
CAROLINAS AND MIDDLE ATLANTIC STATES TODAY AND TONIGHT. ARCTIC HIGH
PRESSURE WILL BUILD EAST OF THE APPALACHIANS WEDNESDAY AND WEDNESDAY
NIGHT...THEN LINGER THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM TUESDAY...
PRECIPITATION HAS BEEN A LITTLE SLOWER THAN EXPECTED TO SPREAD IN TO
CENTRAL NC THIS MORNING...WITH ONLY KINT HAVING REPORTED A LITTLE
MIX OF SLEET AND RAIN THUS FAR. ISENTROPIC UPGLIDE DRIVEN BY A
STRENGHTNEING AND EASTWARD-EXPANDING H85 LLJ OF 35-40 KTS WILL
NONETHELESS SUPPORT FURTHER LIFT AND MOISTENING TO ALLOW INCREASING
RADAR RETURNS PER KGSP RADAR TO OVERSPREAD THE NORTHWEST PIEDMONT
BETWEEN 5 AND 8 AM...PER RECENT RUNS OF THE HRRR AND RAP. THE
SPECIAL RELEASE 06Z KGSO RAOB INDICATED THIS MOISTENING PROCESS WAS
WELL UNDERWAY...WITH JUST A COUPLE OF SHALLOW...BUT STOUT DRY LAYERS
AROUND 10 THOUSAND...AND THE LOWEST 3 THOUSAND...FT REMAINING. THE
FORECAST WET BULB FREEZING LINE IS STILL FORECAST TO RETREAT ACROSS
THE PIEDMONT THROUGH 10-11 AM...A LITTLE MORE SLOWLY THAN EARLIER
PROGGED...AND STILL PROBABLY LINGERING OVER FORSYTH AND PERSON
COUNTIES UNTIL AROUND NOON OR SO. IT WILL TAKE SOME TIME FOR THE
PRECIPITATION TO EDGE INTO THE TRIANGLE - BETWEEN 8-11 AM - AND THE
COASTAL PLAIN DURING THE MIDDAY HOURS. THERE WILL CONSEQUENTLY BE
LITTLE OPPORTUNITY FOR ANYTHING BUT A CHILLY RAIN IN THOSE AREAS...
WITH THE EXCEPTION OF THE FAR NORTHERN REACHES OF NORTHERN DURHAM
COUNTY FOR AN HOUR OR TWO. THE PRECIPITATION AMOUNTS DURING THAT
TIME WILL BE SO LIGHT THAT ANY VERY LIGHT FREEZING RAIN WOULD HAVE
LITTLE TO NO IMPACT. THE BETTER CHANCE OF SEEING SEVERAL
HUNDREDTHS...TO AROUND A TENTH OF AN INCH OVER THE FAR NW
PIEDMONT...WILL OCCUR IN THE CURRENT ADVISORY AREA.
THE OTHER NOTABLE TREND IN GUIDANCE HAS BEEN FOR A MORE INLAND TRACK
OF THE SURFACE LOW TAKING SHAPE OVER THE NORTHERN GULF OF MEXICO...
AND ANOTHER PRECEDING LOW FORECAST TO DEVELOP OVER NC AND VA THIS
EVENING...AS THE FORCING FOR ASCENT ATTENDANT THE NORTHERN STREAM
OVERSPREADS THE LOW LEVEL FRONTAL ZONE. WHILE IT IS STILL LIKELY THE
MODELS ARE TOO AGGRESIVE ERRADICATING THE WEDGE AND BAREELING THE
WARM SECTOR ALL THE WAY INTO THE TRIAD THIS EVENING...IT IS HARD TO
IGNORE THIS MORE INLAND TREND EVEN IN THE HI-RES NMM AND ARW CORES
THAT TEND TO BETTER RESOLVE AND RESPECT CAD. EVEN THEY DRIVE THE
FRONTAL ZONE TO NEAR OR JUST EAST OF HWY 1...AND THIS SOLUTION SEEMS
ACCEPTABLE. BIG TEMPERATURE BUSTS REMAIN LIKELY INVOF THE
FRONT...WHICH WILL LIKELY BE CHARACTERIZED BY A 25-30 DEGREE
TEMPERATURE GRADIENT ACROSS SINGLE COUNTIES...WITH 30S IN THE
RESIUDAL IN-SITU WEDGE OVER THE WESTERN PIEDMONT...AND 60S IN THE
WARM SECTOR. TEMPERATURES WILL CHANGE LITTLE OVERNIGHT...WITH SOME
GRADUAL RISES INTO THE 60S IN THE WARM SECTOR THE MOST LIKELY CHANGE
FROM AFTERNOON TEMPS.
THE MORE INLAND WARM SECTOR PENERTATION ALSO RAISES CONCERN FOR THE
POTENTIAL FOR STRONG TO SEVERE CONVECTION...GIVEN THE EXTREME LOW
AND DEEP SHEAR PROFILES ATTENDING THE RAPIDLY DEEPENING LOW PRESSURE
SYSTEM AND INCREASINGLY-PHASED AND NEGATIVELY-TILTED TROUGH AXES
ALOFT. THIS THREAT WOULD BE HIGHEST OVER THE COASTAL PLAIN AND FAR
EASTERN SANDHILLS AND PIEDMONT AS THE NOSE OF THE LLJ ACCELERATES
ACROSS EAST-CENTRAL NC AND SUPPORTS SCATTERED SURFACE-BASED...OR
NEARLY SO...CONVECTION BETWEEN 7 PM AND 2 AM. FORECST BUFR SOUNDINGS
SUGGEST CONVECTION OF THE ELEVATED VARIETY COULD OCCUR IN THE CAD
REGIME AS WELL...WITH UP TO A FEW HUNDRED J/KG OF MUCAPE INDICATED
ACROSS ALL OF CENTRAL NC FOR SEVERAL HOURS THIS EVENING-EARLY
TONIGHT. A MID LEVEL DRY SLOT MAY LARGELY END PRECIPITATION FOR A
TIME OVERNIGHT...AFTER THE RAIN BECOMES HEAVY AT TIMES DURING THE
AFTERNOON AND EVENING HOURS. THE BULK OF THE PREVIOUSLY FORECAST ONE
TO TWO INCHES OF SOAKING RAIN (WELL BELOW FLASH FLOOD GUIDANCE)...
HIGHEST WEST...WILL HAVE FALLEN BY THAT TIME. THE LEADING EDGE OF
CONCENTRATED DCVA ATTENDING THE POTENT SOUTHERN STREAM SHORTWAVE
TROUGH OVER WEST TX SHOULD THEN RESULT IN THE REDEVELOPMENT OF
RAIN...PERHAPS IN THE FORM OF A BAND OF SHALLOW ELEVATED
CONVECTION...LATE TONIGHT INTO EARLY WEDNESDAY. AREAS OF FOG...
INCLUDING SOME DENSE OVER THE WESTERN PIEDMONT...WILL ALSO BE
PROBABLE ON THE COOL SIDE OF THE BOUNDARY TONIGHT.
&&
.SHORT TERM /WEDNESDAY/...
AS OF 320 PM MONDAY...
FOR WED/WED NIGHT: MODELS ARE IN GOOD AGREEMENT ON PLACING THE
PRIMARY SURFACE LOW NEAR NYC WED MORNING AND THE SECONDARY WEAKER
LOW OVER THE VA TIDEWATER... WHICH BOTH CONSOLIDATE INTO A SINGLE
LOW OVER MAINE BY DAY`S END. THE SOUTHERN STREAM PORTION OF THE
STORM SYSTEM WILL BE WEAKENING AS IT LIFT NORTHEASTWARD THROUGH NC
FROM MID MORNING THROUGH EARLY AFTERNOON... BUT IT WILL STILL BE
QUITE POTENT INDUCING STRONG FORCING FOR ASCENT AS IT MAINTAINS A
NEGATIVE TILT. THE MID-UPPER LEVELS ACCORDING TO FORECAST SOUNDINGS
WILL DRY OUT QUITE A BIT IN THE MORNING AS A DRY SLOT PUNCHES IN
FROM THE SOUTH... SUGGESTING A TRANSITION TO PATCHY DRIZZLE (OR
PERHAPS A LITTLE FREEZING DRIZZLE IN THE FAR NW CWA WHERE SURFACE
WET BULB TEMPS WILL BE DROPPING TO AROUND 32F) AS THE COLDER AIR
ARRIVES POST-FRONT... WITH THE LOWEST 4 KM OR SO STAYING SATURATED.
A SLUG OF DPVA ASSOCIATED WITH THE NORTHERN STREAM PORTION OF THE
MID LEVEL LONGWAVE TROUGH SWINGS THROUGH NW NC WED AFTERNOON
ATTENDING A DEFORMATION ZONE ALOFT... HOWEVER THESE TOO SHOULD BE
WEAKENING AND DON`T APPEAR TO PROVIDE ENOUGH DEEP LAYER LIFT TO RE-
SATURATE THE AIR ABOVE -10C. AS SUCH... BELIEVE THAT A FEW WET
FLAKES WILL BE POSSIBLE ACROSS THE NW AND FAR NRN PIEDMONT WED
AFTERNOON AS THE COLUMN COOLS... BUT IT SHOULD BE INCONSEQUENTIAL
GIVEN THE BRIEF WINDOW OF OPPORTUNITY AND LIMITED MOISTURE ALOFT.
PASSAGE OF A WEAK POST-FRONTAL SURFACE TROUGH WED AFTERNOON WILL
SWING WINDS AROUND TO A UNIFORMLY NW DIRECTION... YIELDING CLEARING
SKIES BY EARLY EVENING AS DOWNSLOPE FLOW AND DRY AIR ADVECTION TAKES
OVER. WITH A TIGHTENING MSLP GRADIENT DUE TO THE STRENGTHENING
DEPARTING SURFACE LOW... THESE BRISK NW WINDS DURING THE DAY ARE
EXPECTED TO TOP OUT AT 15-20 MPH SUSTAINED WITH GUSTS OVER 30 MPH
POSSIBLE AS STRONG 925 MB WINDS NEAR 35 KT MIX DOWN TO THE SURFACE.
WED HIGHS ARE APT TO BE VERY CLOSE TO THE MORNING LOWS... WITH
PLUNGING THICKNESSES THROUGH THE DAY WITH STEADY COLD AIR ADVECTION
CAUSING TEMPS TO FALL SLOWLY THROUGH THE DAY. EARLY DAY HIGHS FROM
THE UPPER 30S NW TO LOWER 60S IN THE EASTERN COASTAL PLAIN...
FALLING TO THE MID 30S NW TO MID 40S EAST BY LATE AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
AS OF 250 AM TUESDAY...
WEDNESDAY NIGHT THROUGH SUNDAY: AS THE COLD FRONT MOVES FARTHER OFF
THE CAROLINA COAST AND THE LOW MOVES NE AWAY FROM THE AREA...SKIES
WILL BEGIN TO CLEAR AND LOW TEMPS FOR WEDNESDAY NIGHT WILL DROP INTO
THE LOW 20S NW TO UPPER 20S EAST. WINDS WILL REMAIN BREEZY OVERNIGHT
UNTIL THE PRESSURE GRADIENT RELAXES AND SURFACE HIGH PRESSURE MOVES
OVER THE APPALACHIANS ON THURSDAY. WITH THE COLD HIGH PRESSURE IN
PLACE...EXPECT HIGHS ON THURSDAY IN THE UPPER 30S TO LOW 40 AND
OVERNIGHT LOWS SIMILAR TO THE PREVIOUS NIGHT...LOW TO UPPER 20S. THE
SURFACE HIGH SHOULD MIGRATE OVER THE GREAT LAKES AND INTO THE
NORTHEAST BY FRIDAY WITH THE RIDGE EXTENDING SOUTHWEST INTO CENTRAL
NC WHERE IT WILL REMAIN THROUGH SUNDAY. THE RESULT WILL BE A DRY
FORECAST...MAINLY CLEAR SKIES AND COLD TEMPERATURES...WITH HIGHS
FRIDAY IN THE MID TO UPPER 40S. HIGHS SATURDAY AND SUNDAY WILL BE
DEPENDENT ON THE EASTWARD EXTENT OF THE WEDGE...BUT FOR NOW EXPECT
GRADUALLY INCREASING HIGHS IN THE EAST INTO THE MID 50S BY SUNDAY...
AND A SLOWER INCREASE IN THE NW...UPPER 40S SUNDAY. EXPECT A SIMILAR
TREND IN OVERNIGHT LOWS...MID 20S TO NEAR 30 DEGREES FRIDAY NIGHT
INCREASING SLIGHTLY INTO THE MID 20S TO LOW 30S FOR SATURDAY NIGHT.
SUNDAY NIGHT THROUGH MONDAY NIGHT: THERE ARE DIFFERENCES BETWEEN THE
MODELS WITH RESPECT TO UPPER LEVEL TROUGH AND PRECIP DEVELOPMENT FOR
THIS PART OF THE FORECAST...BUT THEY INDICATE THE RIDGE WEAKENING
AND CLOUD COVER INCREASING SUNDAY NIGHT AND MONDAY. EXPECT THE
COLUMN TO MOISTEN AND CHANCES FOR PRECIP TO INCREASE...HOWEVER
NAILING DOWN ANY TIMING IS DIFFICULT AT THIS TIME. FOR NOW WILL
GRADUALLY INCREASE PRECIP CHANCES SUNDAY NIGHT THROUGH MONDAY NIGHT.
SHOULD SEE HIGH TEMPS MODERATE A BIT...MID 50S TO LOW 60S FOR
MONDAY. OVERNIGHT LOWS GENERALLY IN THE MID 30S TO LOW 40S.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 115 AM TUESDAY...
24 HOUR TAF PERIOD:
THE MOST TREACHEROUS CONDITIONS FOR THE TAFS WILL BE IN THE TRIAD AS
A POTENT STORM SYSTEM MOVES IN FROM THE SOUTHWEST. NO RAIN OBSERVED
YET AT KINT AND KGSO DESPITE RADAR RETURNS ON THE 0.5 DEGREE
ELEVATION ANGLE. THIS IS OWING TO VERY DRY AIR IN THE LOWER LEVELS
WHICH WILL TAKE A WHILE TO OVERCOME BEFORE PRECIPITATION BEGINS IN
THE TRIAD. AS EVAPORATIVE COOLING OCCURS IN THE LOW LEVELS
TEMPERATURES WILL COOL TO NEAR FREEZING AND A PERIOD OF FREEZING
RAIN IS POSSIBLE AT KINT AND KGSO BEGINNING AROUND 9Z THROUGH 14Z OR
SO BEFORE WARM AIR ADVECTION CAUSES TEMPERATURES TO RECOVER. AT THIS
TIME FREEZING RAIN IS EXPECTED TO GIVE WAY TO AN EXTENDED PERIOD OF
LIGHT TO MODERATE RAIN...WITH POCKETS OF HEAVIER PRECIPITATION
THROUGH THE END OF THE TAF PERIOD. ALREADY MVFR CONDITIONS IN THE
TRIAD ARE EXPECTED TO FURTHER DETERIORATE TO IFR/LIFR AND MOST
LIKELY WILL REMAIN IN THE TANK THROUGH THE PERIOD WITH CEILINGS LESS
THAN 1000 FEET AND VISIBILITIES MAINLY IN THE MVFR RANGE.
CONDITIONS AT THE REMAINING TAF SITES WILL BE SIMILAR BUT WITHOUT
THE PERIOD OF FREEZING RAIN AT THE ONSET AS TEMPERATURES ARE
EXPECTED TO REMAIN ABOVE FREEZING THROUGH THE PERIOD. ANOTHER
CONCERN AT ALL TAF LOCATIONS WILL BE LOW LEVEL WIND SHEAR THAT IS
EXPECTED TO PICK UP JUST AFTER SUNRISE...NEAR 14Z. LIGHT EAST OR
NORTHEASTERLY WINDS IN THE LOW LEVELS WILL RAPIDLY INCREASE TO 35 TO
40 KNOTS OUT OF THE SOUTHEAST NEAR 2 KFT. WHILE THE SEVERITY OF THE
LLWS WILL DECREASE AFTER 00Z WEDNESDAY...LLWS WILL STILL BE A
CONCERN THROUGH THE END OF THE TAF PERIOD WITH THE EXCEPTION OF KRWI
WHERE THE THREAT WILL END EARLIER AS SURFACE WINDS SHOULD BE
STRONGER AND NEAR UNIDIRECTIONAL TO HELP MITIGATE SHEAR POTENTIAL.
LONG TERM: A SECOND STORM SYSTEM WILL FOLLOW RIGHT BEHIND THE FIRST
WHICH WILL CARRY INTO WEDNESDAY BEFORE CLEARING OUT WEDNESDAY NIGHT.
CONDITIONS SHOULD BE PREDOMINATELY VFR THEREAFTER UNTIL EARLY NEXT
WEEK WHEN THE NEXT SYSTEM APPROACHES.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR NCZ007-
021>024-038-039.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...GIH
LONG TERM...KC
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
252 AM EST TUE NOV 26 2013
.SYNOPSIS...A LOW PRESSURE SYSTEM OVER THE NORTHERN GULF OF MEXICO
WILL RAPIDLY INTENSIFY AS IT LIFTS NORTHEASTWARD THROUGH THE
CAROLINAS AND MIDDLE ATLANTIC STATES TODAY AND TONIGHT. ARCTIC HIGH
PRESSURE WILL BUILD EAST OF THE APPALACHIANS WEDNESDAY AND WEDNESDAY
NIGHT...THEN LINGER THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM MONDAY...
TONIGHT: SURFACE HIGH PRESSURE IS CURRENTLY SHIFTING OFF THE NORTH
CAROLINA COAST. HOWEVER... THE LOW LEVELS REMAIN QUITE DRY ACROSS
THE AREA IN THE WAKE OF THE DEPARTING ARCTIC HIGH PRESSURE. ALOFT...
MID AND UPPER LEVEL MOISTURE IS BEGINNING TO STREAM INTO THE AREA IN
ASSOCIATION WITH A STRENGTHENING LOW PRESSURE SYSTEM OVER THE GULF
COAST STATES. THIS SYSTEM WILL QUICKLY APPROACH THE AREA
OVERNIGHT... SPREADING OVERCAST SKIES AND EVENTUALLY PRECIP INTO THE
WEST/NORTHWEST PIEDMONT AFTER MIDNIGHT... THEN SPREADING EASTWARD
ACROSS THE REST OF THE AREA AFTER DAYBREAK. IN FACT WE ARE ALREADY
SEEING SOME RETURNS ON RADAR THIS EVENING. CANT RULE OUT A FEW
SPRINKLES OR SLEET PELLETS LATE THIS EVENING WITH THE BEST
RETURNS... BUT THE AMOUNT OF DRY AIR IN THE LOW LEVEL (AS EVIDENT BY
THE 00Z KGSO SOUNDING ALONG WITH RAP MODELS SOUNDING FOR THE WESTERN
PIEDMONT) SUGGEST ANY PRECIP WILL HAVE A HARD TIME REACHING THE
GROUND OVER THE COURSE OF THE REST OF THE EVENING HOURS. HOWEVER...
WITH LOW LEVEL SOUTHERLY FLOW (925-850 MB) RAMPING UP BELOW THE COLD
DRY SURFACE ALONG WITH INCREASING UPPER DIVERGENCE EXPECT WE WILL
SEE A MOISTENING OF THE LOW LEVELS AND PRECIP BEGINNING TO FALL
ACROSS THE WESTERN/NORTHWESTERN PIEDMONT AFTER MIDNIGHT TONIGHT.
TIMING WISE... THE HRRR IS SHOWING PRECIP MOVING INTO OUR FAR
NORTHWEST PIEDMONT FIRST AROUND 07-09Z... THE MOVING INTO THE REST
OF OUR NORTHWEST PIEDMONT AND WESTERN PIEDMONT COUNTIES BY 12Z...
WITH THE MEASURABLE PRECIP EXPECTED TO BE NEAR RALEIGH BY AROUND
DAYBREAK.
AS THE PRECIP MOVES INTO THE AREA EXPECT WE WILL LIKELY SEE A BRIEF
PERIOD OF SLEET THANKS TO THE DRY LOW LEVEL AIRMASS THE INITIAL
PRECIP WILL FALL THROUGH. THEN... WE WILL NEED TO TAKE A LOOK AT OUR
SURFACE WET-BULB TEMPS AND THE POTENTIAL FOR FREEZING RAIN... AS THE
WARM NOES IS FORECAST TO BE IN EXCESS OF 5 DEGREES C. AND SHOULD
KEEP ANY PRECIP IN THE FORM OF RAIN/FREEZING RAIN AFTER THE INITIAL
LOW LEVEL AIRMASS IS SATURATED. CURRENT SURFACE TEMPS HAVE LEVELED
OFF/INCREASED A BIT WITH THE CLOUD COVER MOVING INTO THE AREA... IN
THE MID TO UPPER 30S. HOWEVER... SURFACE DEWPOINTS ACROSS THE AREA
IN THE SINGLE DIGITS/TEENS WILL ALLOW FOR THE POTENTIAL TO
EVAPORATIVELY COOL OUR TEMPS TO BELOW FREEZING ACROSS PORTIONS OF
OUR NORTHWEST/NORTHERN PIEDMONT EARLY TUESDAY MORNING THROUGH AROUND
15Z OR SO. THE BELOW FREEZING SURFACE WET-BULB TEMPS WHEN SUFFICIENT
PRECIP MOVES INTO THE AREA IN THE 09-12Z TIME FRAME WILL LOWER TEMPS
TO FREEZING OR JUST BELOW FREEZING ACROSS THE COUNTIES LISTED IN OUR
WINTER WEATHER ADVISORY. WILL NOT EXPAND THE ADVISORY AT THIS
TIME... AS CONFIDENCE IS NOT HIGH ENOUGH AT THIS TIME. IF ANY
COUNTIES WOULD NEED TO BE ADDED IT WOULD BE GRANVILLE AND VANCE...
WITH PERHAPS NORTHERN PORTIONS OF DURHAM COUNTY AND NORTHWESTERN
PORTIONS OF CHATHAM COUNTY POSSIBLY CAUSING THE INCLUSION OF THESE
COUNTIES. THE REASON FOR NOT ADDING THESE COUNTIES NOW IS WE WILL
NEED HEAVY ENOUGH PRECIP TO BE ABLE TO EVAPORATIVELY COOL DOWN TO
THE WET-BULB TEMPS. GIVEN THESE AREAS ARE ON THE FRINGE OF
SUFFICIENT PRECIP AND SUB-FREEZING WET-BULB TEMPS WILL HOLD OFF FOR
NOW. EXPECT ANY FREEZING RAIN THREAT SHOULD END BY MID MORNING AS
THE SUPPLY OF COLD DRY AIR AT THE SURFACE WILL BE LIMITED THANKS TO
THE SURFACE HIGH PRESSURE CENTER MOVING OFFSHORE... CREATING AN IN-
SITU DAMMING EVENT. THUS... MAKING THE FREEZING RAIN EVENT A SELF-
LIMITING PROCESS THANKS TO THE LATENT HEATING FROM PHASE CHANGE. ANY
ICE ACCRUAL IS EXPECTED TO BE GENERALLY LIMITED TO A TENTH OF AN
INCH OR LESS... WITH THE HIGHEST AMOUNTS EXPECTED IN NORTHWEST
FORSYTH COUNTY.
LOW TEMPS FOR THIS PERIOD HAVE ALREADY OCCURRED ACROSS MOST OF THE
COASTAL PLAIN COUNTIES... IN THE MID TO UPPER 20S. TEMPS ACROSS
THESE LOCATIONS HAVE RISEN AS CLOUD COVER HAS MOVED INTO THE AREA
THIS EVENING... NOW IN THE MID 30S IN GENERAL. LOWS ACROSS THE
WESTERN AND NORTHERN PIEDMONT SHOULD OCCUR AS THE PRECIP MOVES INTO
THE AREA... WITH LOCATIONS IN THE MIDDLE OF THE CWA GENERALLY
REMAINING NEAR STEADY TONIGHT (MID TO UPPER 30S).
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 320 PM MONDAY...
TUESDAY... PRECIP WILL BECOME WIDESPREAD ACROSS CENTRAL NC DURING
THE FIRST HALF OF THE MORNING. EXPECT WINTRY PRECIP IN THE NW
PIEDMONT TO TRANSITION TO MAINLY A COLD RAIN IN THE LATE MORNING.
POTENTIAL FOR THE ADVISORY TO BE CANCELED PRIOR TO NOON EXPIRATION
IF WARMING OCCURS SOONER OR IS STRONGER THAN EXPECTED. INCREASING
DIVERGENCE ALOFT COUPLED WITH INCREASING CONVERGENCE AS A SFC WARM
FRONT MIGRATES INLAND FROM THE COAST WILL INCREASE THE LIFT THROUGH
THE ENTIRE COLUMN. CONVERGENCE LONG THIS BOUNDARY WILL LEAD TO
ENHANCE PRECIP...LEADING TO LOCALLY HEAVY RAINFALL. BEST SHOT OF
AXIS OF HEAVY RAIN APPEARS TO EXIST IN VICINITY OF THE HIGHWAY 1
CORRIDOR. EXPECT STORM TOTALS AMOUNTS 1-2 INCHES WITH LOCALIZED
AMOUNTS AROUND 2.5 INCHES.
TEMPERATURE-WISE...COLD RAIN WILL ENTRENCH THE TRIAD IN AN IN-SITU
DAMMING EVENT AS TEMPS WILL STRUGGLE THROUGH THE 30S. THE INLAND
ADVANCING WARM FRONT WILL LIKELY CREATE A WIDE TEMP VARIANCE BETWEEN
THE TRIANGLE AND THE COASTAL PLAIN. EXPECT TEMPS TO VARY AS MUCH AS
15-20 DEGREES...RANGING THE 40S-50 IN THE TRIANGLE TO THE LOWER 60S
EAST OF I-95. LATEST MODEL GUIDANCE HAS COME MORE INLAND WITH HE SFC
LOW. IF THIS VERIFIES...POTENTIAL FOR A TEMPERATURE BUST IN VICINITY
OF THE TRIANGLE WHERE A TEMPERATURE SWING OF 10-12 DEGREES MAY
OCCUR. BASED ON LATEST GUIDANCE...MAY ADJUST TEMPS UP 4-7 DEGREES
FROM PREVIOUS FORECAST.
TUESDAY NIGHT... FORECAST STILL CHALLENGING THIS PERIOD...DEPENDENT
UPON EXTENT OF AVAILABLE SFC BASED INSTABILITY AND EVENTUAL TRACK OF
SFC LOW. WIDESPREAD RAIN OR SHOWERS WILL CONTINUE. INCREASING LOW
LEVEL JET (AS HIGH AS 60-65KTS OFF THE NAM)WIL PROVIDE INCREDIBLE
SHEAR AND STORM RELATIVE HELICITY. FORECAST MODEL SOUNDINGS MAINTAIN
A CONDITIONALLY STABLE AIR MASS WITH BEST INSTABILITY ALOFT.
EXCEPTION IS THE NAM WHICH SUGGEST THAT SFC BASED INSTABILITY MAY
OCCUR OVER OUR FAR SE COUNTIES FOR A FEW HOURS LATE TUESDAY NIGHT
(10 PM - 4 AM). BASED ON THE MODEL TREND OF A SFC LOW TRACK A LITTLE
FARTHER INLAND...SOME POTENTIAL FOR A SFC BASED THUNDERSTORM TO
OCCUR WITH A SMALL THREAT FOR A SEVERE STORM WITH DAMAGING WIND
GUSTS OR A BRIEF TORNADO THE MAIN SEVERE WEATHER THREAT.
TEMPS TUESDAY NIGHT WILL HOLD STEADY OR SLOWLY RISE ACROSS MOST
LOCATION EXCLUDING THE NW PIEDMONT WHERE TEMPS WILL HOLD STEADY.
TEMPS IN THE SANDHILLS AND COASTAL PLAIN MAY RISE OR HOLD STEADY IN
THE LOW-MID 60S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 250 AM TUESDAY...
WEDNESDAY NIGHT THROUGH SUNDAY: AS THE COLD FRONT MOVES FARTHER OFF
THE CAROLINA COAST AND THE LOW MOVES NE AWAY FROM THE AREA...SKIES
WILL BEGIN TO CLEAR AND LOW TEMPS FOR WEDNESDAY NIGHT WILL DROP INTO
THE LOW 20S NW TO UPPER 20S EAST. WINDS WILL REMAIN BREEZY OVERNIGHT
UNTIL THE PRESSURE GRADIENT RELAXES AND SURFACE HIGH PRESSURE MOVES
OVER THE APPALACHIANS ON THURSDAY. WITH THE COLD HIGH PRESSURE IN
PLACE...EXPECT HIGHS ON THURSDAY IN THE UPPER 30S TO LOW 40 AND
OVERNIGHT LOWS SIMILAR TO THE PREVIOUS NIGHT...LOW TO UPPER 20S. THE
SURFACE HIGH SHOULD MIGRATE OVER THE GREAT LAKES AND INTO THE
NORTHEAST BY FRIDAY WITH THE RIDGE EXTENDING SOUTHWEST INTO CENTRAL
NC WHERE IT WILL REMAIN THROUGH SUNDAY. THE RESULT WILL BE A DRY
FORECAST...MAINLY CLEAR SKIES AND COLD TEMPERATURES...WITH HIGHS
FRIDAY IN THE MID TO UPPER 40S. HIGHS SATURDAY AND SUNDAY WILL BE
DEPENDENT ON THE EASTWARD EXTENT OF THE WEDGE...BUT FOR NOW EXPECT
GRADUALLY INCREASING HIGHS IN THE EAST INTO THE MID 50S BY SUNDAY...
AND A SLOWER INCREASE IN THE NW...UPPER 40S SUNDAY. EXPECT A SIMILAR
TREND IN OVERNIGHT LOWS...MID 20S TO NEAR 30 DEGREES FRIDAY NIGHT
INCREASING SLIGHTLY INTO THE MID 20S TO LOW 30S FOR SATURDAY NIGHT.
SUNDAY NIGHT THROUGH MONDAY NIGHT: THERE ARE DIFFERENCES BETWEEN THE
MODELS WITH RESPECT TO UPPER LEVEL TROUGH AND PRECIP DEVELOPMENT FOR
THIS PART OF THE FORECAST...BUT THEY INDICATE THE RIDGE WEAKENING
AND CLOUD COVER INCREASING SUNDAY NIGHT AND MONDAY. EXPECT THE
COLUMN TO MOISTEN AND CHANCES FOR PRECIP TO INCREASE...HOWEVER
NAILING DOWN ANY TIMING IS DIFFICULT AT THIS TIME. FOR NOW WILL
GRADUALLY INCREASE PRECIP CHANCES SUNDAY NIGHT THROUGH MONDAY NIGHT.
SHOULD SEE HIGH TEMPS MODERATE A BIT...MID 50S TO LOW 60S FOR
MONDAY. OVERNIGHT LOWS GENERALLY IN THE MID 30S TO LOW 40S.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 115 AM TUESDAY...
24 HOUR TAF PERIOD:
THE MOST TREACHEROUS CONDITIONS FOR THE TAFS WILL BE IN THE TRIAD AS
A POTENT STORM SYSTEM MOVES IN FROM THE SOUTHWEST. NO RAIN OBSERVED
YET AT KINT AND KGSO DESPITE RADAR RETURNS ON THE 0.5 DEGREE
ELEVATION ANGLE. THIS IS OWING TO VERY DRY AIR IN THE LOWER LEVELS
WHICH WILL TAKE A WHILE TO OVERCOME BEFORE PRECIPITATION BEGINS IN
THE TRIAD. AS EVAPORATIVE COOLING OCCURS IN THE LOW LEVELS
TEMPERATURES WILL COOL TO NEAR FREEZING AND A PERIOD OF FREEZING
RAIN IS POSSIBLE AT KINT AND KGSO BEGINNING AROUND 9Z THROUGH 14Z OR
SO BEFORE WARM AIR ADVECTION CAUSES TEMPERATURES TO RECOVER. AT THIS
TIME FREEZING RAIN IS EXPECTED TO GIVE WAY TO AN EXTENDED PERIOD OF
LIGHT TO MODERATE RAIN...WITH POCKETS OF HEAVIER PRECIPITATION
THROUGH THE END OF THE TAF PERIOD. ALREADY MVFR CONDITIONS IN THE
TRIAD ARE EXPECTED TO FURTHER DETERIORATE TO IFR/LIFR AND MOST
LIKELY WILL REMAIN IN THE TANK THROUGH THE PERIOD WITH CEILINGS LESS
THAN 1000 FEET AND VISIBILITIES MAINLY IN THE MVFR RANGE.
CONDITIONS AT THE REMAINING TAF SITES WILL BE SIMILAR BUT WITHOUT
THE PERIOD OF FREEZING RAIN AT THE ONSET AS TEMPERATURES ARE
EXPECTED TO REMAIN ABOVE FREEZING THROUGH THE PERIOD. ANOTHER
CONCERN AT ALL TAF LOCATIONS WILL BE LOW LEVEL WIND SHEAR THAT IS
EXPECTED TO PICK UP JUST AFTER SUNRISE...NEAR 14Z. LIGHT EAST OR
NORTHEASTERLY WINDS IN THE LOW LEVELS WILL RAPIDLY INCREASE TO 35 TO
40 KNOTS OUT OF THE SOUTHEAST NEAR 2 KFT. WHILE THE SEVERITY OF THE
LLWS WILL DECREASE AFTER 00Z WEDNESDAY...LLWS WILL STILL BE A
CONCERN THROUGH THE END OF THE TAF PERIOD WITH THE EXCEPTION OF KRWI
WHERE THE THREAT WILL END EARLIER AS SURFACE WINDS SHOULD BE
STRONGER AND NEAR UNIDIRECTIONAL TO HELP MITIGATE SHEAR POTENTIAL.
LONG TERM: A SECOND STORM SYSTEM WILL FOLLOW RIGHT BEHIND THE FIRST
WHICH WILL CARRY INTO WEDNESDAY BEFORE CLEARING OUT WEDNESDAY NIGHT.
CONDITIONS SHOULD BE PREDOMINATELY VFR THEREAFTER UNTIL EARLY NEXT
WEEK WHEN THE NEXT SYSTEM APPROACHES.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR NCZ007-
021>024-038-039.
&&
$$
SYNOPSIS...MWS
NEAR TERM...BSD
SHORT TERM...WSS
LONG TERM...KC
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
251 AM EST TUE NOV 26 2013
.SYNOPSIS...A LOW PRESSURE SYSTEM OVER THE NORTHERN GULF OF MEXICO
WILL RAPIDLY INTENSIFY AS IT LIFTS NORTHEASTWARD THROUGH THE
CAROLINAS AND MIDDLE ATLANTIC STATES TODAY AND TONIGHT. ARCTIC HIGH
PRESSURE WILL BUILD EAST OF THE APPALACHIANS WEDNESDAY AND WEDNESDAY
NIGHT...THEN LINGER THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM MONDAY...
TONIGHT: SURFACE HIGH PRESSURE IS CURRENTLY SHIFTING OFF THE NORTH
CAROLINA COAST. HOWEVER... THE LOW LEVELS REMAIN QUITE DRY ACROSS
THE AREA IN THE WAKE OF THE DEPARTING ARCTIC HIGH PRESSURE. ALOFT...
MID AND UPPER LEVEL MOISTURE IS BEGINNING TO STREAM INTO THE AREA IN
ASSOCIATION WITH A STRENGTHENING LOW PRESSURE SYSTEM OVER THE GULF
COAST STATES. THIS SYSTEM WILL QUICKLY APPROACH THE AREA
OVERNIGHT... SPREADING OVERCAST SKIES AND EVENTUALLY PRECIP INTO THE
WEST/NORTHWEST PIEDMONT AFTER MIDNIGHT... THEN SPREADING EASTWARD
ACROSS THE REST OF THE AREA AFTER DAYBREAK. IN FACT WE ARE ALREADY
SEEING SOME RETURNS ON RADAR THIS EVENING. CANT RULE OUT A FEW
SPRINKLES OR SLEET PELLETS LATE THIS EVENING WITH THE BEST
RETURNS... BUT THE AMOUNT OF DRY AIR IN THE LOW LEVEL (AS EVIDENT BY
THE 00Z KGSO SOUNDING ALONG WITH RAP MODELS SOUNDING FOR THE WESTERN
PIEDMONT) SUGGEST ANY PRECIP WILL HAVE A HARD TIME REACHING THE
GROUND OVER THE COURSE OF THE REST OF THE EVENING HOURS. HOWEVER...
WITH LOW LEVEL SOUTHERLY FLOW (925-850 MB) RAMPING UP BELOW THE COLD
DRY SURFACE ALONG WITH INCREASING UPPER DIVERGENCE EXPECT WE WILL
SEE A MOISTENING OF THE LOW LEVELS AND PRECIP BEGINNING TO FALL
ACROSS THE WESTERN/NORTHWESTERN PIEDMONT AFTER MIDNIGHT TONIGHT.
TIMING WISE... THE HRRR IS SHOWING PRECIP MOVING INTO OUR FAR
NORTHWEST PIEDMONT FIRST AROUND 07-09Z... THE MOVING INTO THE REST
OF OUR NORTHWEST PIEDMONT AND WESTERN PIEDMONT COUNTIES BY 12Z...
WITH THE MEASURABLE PRECIP EXPECTED TO BE NEAR RALEIGH BY AROUND
DAYBREAK.
AS THE PRECIP MOVES INTO THE AREA EXPECT WE WILL LIKELY SEE A BRIEF
PERIOD OF SLEET THANKS TO THE DRY LOW LEVEL AIRMASS THE INITIAL
PRECIP WILL FALL THROUGH. THEN... WE WILL NEED TO TAKE A LOOK AT OUR
SURFACE WET-BULB TEMPS AND THE POTENTIAL FOR FREEZING RAIN... AS THE
WARM NOES IS FORECAST TO BE IN EXCESS OF 5 DEGREES C. AND SHOULD
KEEP ANY PRECIP IN THE FORM OF RAIN/FREEZING RAIN AFTER THE INITIAL
LOW LEVEL AIRMASS IS SATURATED. CURRENT SURFACE TEMPS HAVE LEVELED
OFF/INCREASED A BIT WITH THE CLOUD COVER MOVING INTO THE AREA... IN
THE MID TO UPPER 30S. HOWEVER... SURFACE DEWPOINTS ACROSS THE AREA
IN THE SINGLE DIGITS/TEENS WILL ALLOW FOR THE POTENTIAL TO
EVAPORATIVELY COOL OUR TEMPS TO BELOW FREEZING ACROSS PORTIONS OF
OUR NORTHWEST/NORTHERN PIEDMONT EARLY TUESDAY MORNING THROUGH AROUND
15Z OR SO. THE BELOW FREEZING SURFACE WET-BULB TEMPS WHEN SUFFICIENT
PRECIP MOVES INTO THE AREA IN THE 09-12Z TIME FRAME WILL LOWER TEMPS
TO FREEZING OR JUST BELOW FREEZING ACROSS THE COUNTIES LISTED IN OUR
WINTER WEATHER ADVISORY. WILL NOT EXPAND THE ADVISORY AT THIS
TIME... AS CONFIDENCE IS NOT HIGH ENOUGH AT THIS TIME. IF ANY
COUNTIES WOULD NEED TO BE ADDED IT WOULD BE GRANVILLE AND VANCE...
WITH PERHAPS NORTHERN PORTIONS OF DURHAM COUNTY AND NORTHWESTERN
PORTIONS OF CHATHAM COUNTY POSSIBLY CAUSING THE INCLUSION OF THESE
COUNTIES. THE REASON FOR NOT ADDING THESE COUNTIES NOW IS WE WILL
NEED HEAVY ENOUGH PRECIP TO BE ABLE TO EVAPORATIVELY COOL DOWN TO
THE WET-BULB TEMPS. GIVEN THESE AREAS ARE ON THE FRINGE OF
SUFFICIENT PRECIP AND SUB-FREEZING WET-BULB TEMPS WILL HOLD OFF FOR
NOW. EXPECT ANY FREEZING RAIN THREAT SHOULD END BY MID MORNING AS
THE SUPPLY OF COLD DRY AIR AT THE SURFACE WILL BE LIMITED THANKS TO
THE SURFACE HIGH PRESSURE CENTER MOVING OFFSHORE... CREATING AN IN-
SITU DAMMING EVENT. THUS... MAKING THE FREEZING RAIN EVENT A SELF-
LIMITING PROCESS THANKS TO THE LATENT HEATING FROM PHASE CHANGE. ANY
ICE ACCRUAL IS EXPECTED TO BE GENERALLY LIMITED TO A TENTH OF AN
INCH OR LESS... WITH THE HIGHEST AMOUNTS EXPECTED IN NORTHWEST
FORSYTH COUNTY.
LOW TEMPS FOR THIS PERIOD HAVE ALREADY OCCURRED ACROSS MOST OF THE
COASTAL PLAIN COUNTIES... IN THE MID TO UPPER 20S. TEMPS ACROSS
THESE LOCATIONS HAVE RISEN AS CLOUD COVER HAS MOVED INTO THE AREA
THIS EVENING... NOW IN THE MID 30S IN GENERAL. LOWS ACROSS THE
WESTERN AND NORTHERN PIEDMONT SHOULD OCCUR AS THE PRECIP MOVES INTO
THE AREA... WITH LOCATIONS IN THE MIDDLE OF THE CWA GENERALLY
REMAINING NEAR STEADY TONIGHT (MID TO UPPER 30S).
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 320 PM MONDAY...
TUESDAY... PRECIP WILL BECOME WIDESPREAD ACROSS CENTRAL NC DURING
THE FIRST HALF OF THE MORNING. EXPECT WINTRY PRECIP IN THE NW
PIEDMONT TO TRANSITION TO MAINLY A COLD RAIN IN THE LATE MORNING.
POTENTIAL FOR THE ADVISORY TO BE CANCELED PRIOR TO NOON EXPIRATION
IF WARMING OCCURS SOONER OR IS STRONGER THAN EXPECTED. INCREASING
DIVERGENCE ALOFT COUPLED WITH INCREASING CONVERGENCE AS A SFC WARM
FRONT MIGRATES INLAND FROM THE COAST WILL INCREASE THE LIFT THROUGH
THE ENTIRE COLUMN. CONVERGENCE LONG THIS BOUNDARY WILL LEAD TO
ENHANCE PRECIP...LEADING TO LOCALLY HEAVY RAINFALL. BEST SHOT OF
AXIS OF HEAVY RAIN APPEARS TO EXIST IN VICINITY OF THE HIGHWAY 1
CORRIDOR. EXPECT STORM TOTALS AMOUNTS 1-2 INCHES WITH LOCALIZED
AMOUNTS AROUND 2.5 INCHES.
TEMPERATURE-WISE...COLD RAIN WILL ENTRENCH THE TRIAD IN AN IN-SITU
DAMMING EVENT AS TEMPS WILL STRUGGLE THROUGH THE 30S. THE INLAND
ADVANCING WARM FRONT WILL LIKELY CREATE A WIDE TEMP VARIANCE BETWEEN
THE TRIANGLE AND THE COASTAL PLAIN. EXPECT TEMPS TO VARY AS MUCH AS
15-20 DEGREES...RANGING THE 40S-50 IN THE TRIANGLE TO THE LOWER 60S
EAST OF I-95. LATEST MODEL GUIDANCE HAS COME MORE INLAND WITH HE SFC
LOW. IF THIS VERIFIES...POTENTIAL FOR A TEMPERATURE BUST IN VICINITY
OF THE TRIANGLE WHERE A TEMPERATURE SWING OF 10-12 DEGREES MAY
OCCUR. BASED ON LATEST GUIDANCE...MAY ADJUST TEMPS UP 4-7 DEGREES
FROM PREVIOUS FORECAST.
TUESDAY NIGHT... FORECAST STILL CHALLENGING THIS PERIOD...DEPENDENT
UPON EXTENT OF AVAILABLE SFC BASED INSTABILITY AND EVENTUAL TRACK OF
SFC LOW. WIDESPREAD RAIN OR SHOWERS WILL CONTINUE. INCREASING LOW
LEVEL JET (AS HIGH AS 60-65KTS OFF THE NAM)WIL PROVIDE INCREDIBLE
SHEAR AND STORM RELATIVE HELICITY. FORECAST MODEL SOUNDINGS MAINTAIN
A CONDITIONALLY STABLE AIR MASS WITH BEST INSTABILITY ALOFT.
EXCEPTION IS THE NAM WHICH SUGGEST THAT SFC BASED INSTABILITY MAY
OCCUR OVER OUR FAR SE COUNTIES FOR A FEW HOURS LATE TUESDAY NIGHT
(10 PM - 4 AM). BASED ON THE MODEL TREND OF A SFC LOW TRACK A LITTLE
FARTHER INLAND...SOME POTENTIAL FOR A SFC BASED THUNDERSTORM TO
OCCUR WITH A SMALL THREAT FOR A SEVERE STORM WITH DAMAGING WIND
GUSTS OR A BRIEF TORNADO THE MAIN SEVERE WEATHER THREAT.
TEMPS TUESDAY NIGHT WILL HOLD STEADY OR SLOWLY RISE ACROSS MOST
LOCATION EXCLUDING THE NW PIEDMONT WHERE TEMPS WILL HOLD STEADY.
TEMPS IN THE SANDHILLS AND COASTAL PLAIN MAY RISE OR HOLD STEADY IN
THE LOW-MID 60S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY NIGHT/... AS OF 250 AM
TUESDAY...
WEDNESDAY NIGHT THROUGH SUNDAY: AS THE COLD FRONT MOVES FARTHER OFF
THE CAROLINA COAST AND THE LOW MOVES NE AWAY FROM THE AREA...SKIES
WILL BEGIN TO CLEAR AND LOW TEMPS FOR WEDNESDAY NIGHT WILL DROP INTO
THE LOW 20S NW TO UPPER 20S EAST. WINDS WILL REMAIN BREEZY OVERNIGHT
UNTIL THE PRESSURE GRADIENT RELAXES AND SURFACE HIGH PRESSURE MOVES
OVER THE APPALACHIANS ON THURSDAY. WITH THE COLD HIGH PRESSURE IN
PLACE...EXPECT HIGHS ON THURSDAY IN THE UPPER 30S TO LOW 40 AND
OVERNIGHT LOWS SIMILAR TO THE PREVIOUS NIGHT...LOW TO UPPER 20S. THE
SURFACE HIGH SHOULD MIGRATE OVER THE GREAT LAKES AND INTO THE
NORTHEAST BY FRIDAY WITH THE RIDGE EXTENDING SOUTHWEST INTO CENTRAL
NC WHERE IT WILL REMAIN THROUGH SUNDAY. THE RESULT WILL BE A DRY
FORECAST...MAINLY CLEAR SKIES AND COLD TEMPERATURES...WITH HIGHS
FRIDAY IN THE MID TO UPPER 40S. HIGHS SATURDAY AND SUNDAY WILL BE
DEPENDENT ON THE EASTWARD EXTENT OF THE WEDGE...BUT FOR NOW EXPECT
GRADUALLY INCREASING HIGHS IN THE EAST INTO THE MID 50S BY SUNDAY...
AND A SLOWER INCREASE IN THE NW...UPPER 40S SUNDAY. EXPECT A SIMILAR
TREND IN OVERNIGHT LOWS...MID 20S TO NEAR 30 DEGREES FRIDAY NIGHT
INCREASING SLIGHTLY INTO THE MID 20S TO LOW 30S FOR SATURDAY NIGHT.
SUNDAY NIGHT THROUGH MONDAY NIGHT: THERE ARE DIFFERENCES BETWEEN THE
MODELS WITH RESPECT TO UPPER LEVEL TROUGH AND PRECIP DEVELOPMENT FOR
THIS PART OF THE FORECAST...BUT THEY INDICATE THE RIDGE WEAKENING
AND CLOUD COVER INCREASING SUNDAY NIGHT AND MONDAY. EXPECT THE
COLUMN TO MOISTEN AND CHANCES FOR PRECIP TO INCREASE...HOWEVER
NAILING DOWN ANY TIMING IS DIFFICULT AT THIS TIME. FOR NOW WILL
GRADUALLY INCREASE PRECIP CHANCES SUNDAY NIGHT THROUGH MONDAY NIGHT.
SHOULD SEE HIGH TEMPS MODERATE A BIT...MID 50S TO LOW 60S FOR
MONDAY. OVERNIGHT LOWS GENERALLY IN THE MID 30S TO LOW 40S.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 115 AM TUESDAY...
24 HOUR TAF PERIOD:
THE MOST TREACHEROUS CONDITIONS FOR THE TAFS WILL BE IN THE TRIAD AS
A POTENT STORM SYSTEM MOVES IN FROM THE SOUTHWEST. NO RAIN OBSERVED
YET AT KINT AND KGSO DESPITE RADAR RETURNS ON THE 0.5 DEGREE
ELEVATION ANGLE. THIS IS OWING TO VERY DRY AIR IN THE LOWER LEVELS
WHICH WILL TAKE A WHILE TO OVERCOME BEFORE PRECIPITATION BEGINS IN
THE TRIAD. AS EVAPORATIVE COOLING OCCURS IN THE LOW LEVELS
TEMPERATURES WILL COOL TO NEAR FREEZING AND A PERIOD OF FREEZING
RAIN IS POSSIBLE AT KINT AND KGSO BEGINNING AROUND 9Z THROUGH 14Z OR
SO BEFORE WARM AIR ADVECTION CAUSES TEMPERATURES TO RECOVER. AT THIS
TIME FREEZING RAIN IS EXPECTED TO GIVE WAY TO AN EXTENDED PERIOD OF
LIGHT TO MODERATE RAIN...WITH POCKETS OF HEAVIER PRECIPITATION
THROUGH THE END OF THE TAF PERIOD. ALREADY MVFR CONDITIONS IN THE
TRIAD ARE EXPECTED TO FURTHER DETERIORATE TO IFR/LIFR AND MOST
LIKELY WILL REMAIN IN THE TANK THROUGH THE PERIOD WITH CEILINGS LESS
THAN 1000 FEET AND VISIBILITIES MAINLY IN THE MVFR RANGE.
CONDITIONS AT THE REMAINING TAF SITES WILL BE SIMILAR BUT WITHOUT
THE PERIOD OF FREEZING RAIN AT THE ONSET AS TEMPERATURES ARE
EXPECTED TO REMAIN ABOVE FREEZING THROUGH THE PERIOD. ANOTHER
CONCERN AT ALL TAF LOCATIONS WILL BE LOW LEVEL WIND SHEAR THAT IS
EXPECTED TO PICK UP JUST AFTER SUNRISE...NEAR 14Z. LIGHT EAST OR
NORTHEASTERLY WINDS IN THE LOW LEVELS WILL RAPIDLY INCREASE TO 35 TO
40 KNOTS OUT OF THE SOUTHEAST NEAR 2 KFT. WHILE THE SEVERITY OF THE
LLWS WILL DECREASE AFTER 00Z WEDNESDAY...LLWS WILL STILL BE A
CONCERN THROUGH THE END OF THE TAF PERIOD WITH THE EXCEPTION OF KRWI
WHERE THE THREAT WILL END EARLIER AS SURFACE WINDS SHOULD BE
STRONGER AND NEAR UNIDIRECTIONAL TO HELP MITIGATE SHEAR POTENTIAL.
LONG TERM: A SECOND STORM SYSTEM WILL FOLLOW RIGHT BEHIND THE FIRST
WHICH WILL CARRY INTO WEDNESDAY BEFORE CLEARING OUT WEDNESDAY NIGHT.
CONDITIONS SHOULD BE PREDOMINATELY VFR THEREAFTER UNTIL EARLY NEXT
WEEK WHEN THE NEXT SYSTEM APPROACHES.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR NCZ007-
021>024-038-039.
&&
$$
SYNOPSIS...MWS
NEAR TERM...BSD
SHORT TERM...WSS
LONG TERM...KC
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
114 AM EST TUE NOV 26 2013
.SYNOPSIS... A LOW PRESSURE SYSTEM WILL DEVELOP IN THE GULF OF
MEXICO TONIGHT...THEN INTENSIFY AND TRACK NORTHEAST ALONG THE
CAROLINA AND MID ATLANTIC COAST LATE TUESDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM MONDAY...
TONIGHT: SURFACE HIGH PRESSURE IS CURRENTLY SHIFTING OFF THE NORTH
CAROLINA COAST. HOWEVER... THE LOW LEVELS REMAIN QUITE DRY ACROSS
THE AREA IN THE WAKE OF THE DEPARTING ARCTIC HIGH PRESSURE. ALOFT...
MID AND UPPER LEVEL MOISTURE IS BEGINNING TO STREAM INTO THE AREA IN
ASSOCIATION WITH A STRENGTHENING LOW PRESSURE SYSTEM OVER THE GULF
COAST STATES. THIS SYSTEM WILL QUICKLY APPROACH THE AREA
OVERNIGHT... SPREADING OVERCAST SKIES AND EVENTUALLY PRECIP INTO THE
WEST/NORTHWEST PIEDMONT AFTER MIDNIGHT... THEN SPREADING EASTWARD
ACROSS THE REST OF THE AREA AFTER DAYBREAK. IN FACT WE ARE ALREADY
SEEING SOME RETURNS ON RADAR THIS EVENING. CANT RULE OUT A FEW
SPRINKLES OR SLEET PELLETS LATE THIS EVENING WITH THE BEST
RETURNS... BUT THE AMOUNT OF DRY AIR IN THE LOW LEVEL (AS EVIDENT BY
THE 00Z KGSO SOUNDING ALONG WITH RAP MODELS SOUNDING FOR THE WESTERN
PIEDMONT) SUGGEST ANY PRECIP WILL HAVE A HARD TIME REACHING THE
GROUND OVER THE COURSE OF THE REST OF THE EVENING HOURS. HOWEVER...
WITH LOW LEVEL SOUTHERLY FLOW (925-850 MB) RAMPING UP BELOW THE COLD
DRY SURFACE ALONG WITH INCREASING UPPER DIVERGENCE EXPECT WE WILL
SEE A MOISTENING OF THE LOW LEVELS AND PRECIP BEGINNING TO FALL
ACROSS THE WESTERN/NORTHWESTERN PIEDMONT AFTER MIDNIGHT TONIGHT.
TIMING WISE... THE HRRR IS SHOWING PRECIP MOVING INTO OUR FAR
NORTHWEST PIEDMONT FIRST AROUND 07-09Z... THE MOVING INTO THE REST
OF OUR NORTHWEST PIEDMONT AND WESTERN PIEDMONT COUNTIES BY 12Z...
WITH THE MEASURABLE PRECIP EXPECTED TO BE NEAR RALEIGH BY AROUND
DAYBREAK.
AS THE PRECIP MOVES INTO THE AREA EXPECT WE WILL LIKELY SEE A BRIEF
PERIOD OF SLEET THANKS TO THE DRY LOW LEVEL AIRMASS THE INITIAL
PRECIP WILL FALL THROUGH. THEN... WE WILL NEED TO TAKE A LOOK AT OUR
SURFACE WET-BULB TEMPS AND THE POTENTIAL FOR FREEZING RAIN... AS THE
WARM NOES IS FORECAST TO BE IN EXCESS OF 5 DEGREES C. AND SHOULD
KEEP ANY PRECIP IN THE FORM OF RAIN/FREEZING RAIN AFTER THE INITIAL
LOW LEVEL AIRMASS IS SATURATED. CURRENT SURFACE TEMPS HAVE LEVELED
OFF/INCREASED A BIT WITH THE CLOUD COVER MOVING INTO THE AREA... IN
THE MID TO UPPER 30S. HOWEVER... SURFACE DEWPOINTS ACROSS THE AREA
IN THE SINGLE DIGITS/TEENS WILL ALLOW FOR THE POTENTIAL TO
EVAPORATIVELY COOL OUR TEMPS TO BELOW FREEZING ACROSS PORTIONS OF
OUR NORTHWEST/NORTHERN PIEDMONT EARLY TUESDAY MORNING THROUGH AROUND
15Z OR SO. THE BELOW FREEZING SURFACE WET-BULB TEMPS WHEN SUFFICIENT
PRECIP MOVES INTO THE AREA IN THE 09-12Z TIME FRAME WILL LOWER TEMPS
TO FREEZING OR JUST BELOW FREEZING ACROSS THE COUNTIES LISTED IN OUR
WINTER WEATHER ADVISORY. WILL NOT EXPAND THE ADVISORY AT THIS
TIME... AS CONFIDENCE IS NOT HIGH ENOUGH AT THIS TIME. IF ANY
COUNTIES WOULD NEED TO BE ADDED IT WOULD BE GRANVILLE AND VANCE...
WITH PERHAPS NORTHERN PORTIONS OF DURHAM COUNTY AND NORTHWESTERN
PORTIONS OF CHATHAM COUNTY POSSIBLY CAUSING THE INCLUSION OF THESE
COUNTIES. THE REASON FOR NOT ADDING THESE COUNTIES NOW IS WE WILL
NEED HEAVY ENOUGH PRECIP TO BE ABLE TO EVAPORATIVELY COOL DOWN TO
THE WET-BULB TEMPS. GIVEN THESE AREAS ARE ON THE FRINGE OF
SUFFICIENT PRECIP AND SUB-FREEZING WET-BULB TEMPS WILL HOLD OFF FOR
NOW. EXPECT ANY FREEZING RAIN THREAT SHOULD END BY MID MORNING AS
THE SUPPLY OF COLD DRY AIR AT THE SURFACE WILL BE LIMITED THANKS TO
THE SURFACE HIGH PRESSURE CENTER MOVING OFFSHORE... CREATING AN IN-
SITU DAMMING EVENT. THUS... MAKING THE FREEZING RAIN EVENT A SELF-
LIMITING PROCESS THANKS TO THE LATENT HEATING FROM PHASE CHANGE. ANY
ICE ACCRUAL IS EXPECTED TO BE GENERALLY LIMITED TO A TENTH OF AN
INCH OR LESS... WITH THE HIGHEST AMOUNTS EXPECTED IN NORTHWEST
FORSYTH COUNTY.
LOW TEMPS FOR THIS PERIOD HAVE ALREADY OCCURRED ACROSS MOST OF THE
COASTAL PLAIN COUNTIES... IN THE MID TO UPPER 20S. TEMPS ACROSS
THESE LOCATIONS HAVE RISEN AS CLOUD COVER HAS MOVED INTO THE AREA
THIS EVENING... NOW IN THE MID 30S IN GENERAL. LOWS ACROSS THE
WESTERN AND NORTHERN PIEDMONT SHOULD OCCUR AS THE PRECIP MOVES INTO
THE AREA... WITH LOCATIONS IN THE MIDDLE OF THE CWA GENERALLY
REMAINING NEAR STEADY TONIGHT (MID TO UPPER 30S).
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 320 PM MONDAY...
TUESDAY... PRECIP WILL BECOME WIDESPREAD ACROSS CENTRAL NC DURING
THE FIRST HALF OF THE MORNING. EXPECT WINTRY PRECIP IN THE NW
PIEDMONT TO TRANSITION TO MAINLY A COLD RAIN IN THE LATE MORNING.
POTENTIAL FOR THE ADVISORY TO BE CANCELED PRIOR TO NOON EXPIRATION
IF WARMING OCCURS SOONER OR IS STRONGER THAN EXPECTED. INCREASING
DIVERGENCE ALOFT COUPLED WITH INCREASING CONVERGENCE AS A SFC WARM
FRONT MIGRATES INLAND FROM THE COAST WILL INCREASE THE LIFT THROUGH
THE ENTIRE COLUMN. CONVERGENCE LONG THIS BOUNDARY WILL LEAD TO
ENHANCE PRECIP...LEADING TO LOCALLY HEAVY RAINFALL. BEST SHOT OF
AXIS OF HEAVY RAIN APPEARS TO EXIST IN VICINITY OF THE HIGHWAY 1
CORRIDOR. EXPECT STORM TOTALS AMOUNTS 1-2 INCHES WITH LOCALIZED
AMOUNTS AROUND 2.5 INCHES.
TEMPERATURE-WISE...COLD RAIN WILL ENTRENCH THE TRIAD IN AN IN-SITU
DAMMING EVENT AS TEMPS WILL STRUGGLE THROUGH THE 30S. THE INLAND
ADVANCING WARM FRONT WILL LIKELY CREATE A WIDE TEMP VARIANCE BETWEEN
THE TRIANGLE AND THE COASTAL PLAIN. EXPECT TEMPS TO VARY AS MUCH AS
15-20 DEGREES...RANGING THE 40S-50 IN THE TRIANGLE TO THE LOWER 60S
EAST OF I-95. LATEST MODEL GUIDANCE HAS COME MORE INLAND WITH HE SFC
LOW. IF THIS VERIFIES...POTENTIAL FOR A TEMPERATURE BUST IN VICINITY
OF THE TRIANGLE WHERE A TEMPERATURE SWING OF 10-12 DEGREES MAY
OCCUR. BASED ON LATEST GUIDANCE...MAY ADJUST TEMPS UP 4-7 DEGREES
FROM PREVIOUS FORECAST.
TUESDAY NIGHT... FORECAST STILL CHALLENGING THIS PERIOD...DEPENDENT
UPON EXTENT OF AVAILABLE SFC BASED INSTABILITY AND EVENTUAL TRACK OF
SFC LOW. WIDESPREAD RAIN OR SHOWERS WILL CONTINUE. INCREASING LOW
LEVEL JET (AS HIGH AS 60-65KTS OFF THE NAM)WIL PROVIDE INCREDIBLE
SHEAR AND STORM RELATIVE HELICITY. FORECAST MODEL SOUNDINGS MAINTAIN
A CONDITIONALLY STABLE AIR MASS WITH BEST INSTABILITY ALOFT.
EXCEPTION IS THE NAM WHICH SUGGEST THAT SFC BASED INSTABILITY MAY
OCCUR OVER OUR FAR SE COUNTIES FOR A FEW HOURS LATE TUESDAY NIGHT
(10 PM - 4 AM). BASED ON THE MODEL TREND OF A SFC LOW TRACK A LITTLE
FARTHER INLAND...SOME POTENTIAL FOR A SFC BASED THUNDERSTORM TO
OCCUR WITH A SMALL THREAT FOR A SEVERE STORM WITH DAMAGING WIND
GUSTS OR A BRIEF TORNADO THE MAIN SEVERE WEATHER THREAT.
TEMPS TUESDAY NIGHT WILL HOLD STEADY OR SLOWLY RISE ACROSS MOST
LOCATION EXCLUDING THE NW PIEDMONT WHERE TEMPS WILL HOLD STEADY.
TEMPS IN THE SANDHILLS AND COASTAL PLAIN MAY RISE OR HOLD STEADY IN
THE LOW-MID 60S.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 325 PM MONDAY...
FOR WED/WED NIGHT: MODELS ARE IN GOOD AGREEMENT ON PLACING THE
PRIMARY SURFACE LOW NEAR NYC WED MORNING AND THE SECONDARY WEAKER
LOW OVER THE VA TIDEWATER... WHICH BOTH CONSOLIDATE INTO A SINGLE
LOW OVER MAINE BY DAY`S END. THE SOUTHERN STREAM PORTION OF THE
STORM SYSTEM WILL BE WEAKENING AS IT LIFT NORTHEASTWARD THROUGH NC
FROM MID MORNING THROUGH EARLY AFTERNOON... BUT IT WILL STILL BE
QUITE POTENT INDUCING STRONG FORCING FOR ASCENT AS IT MAINTAINS A
NEGATIVE TILT. THE MID-UPPER LEVELS ACCORDING TO FORECAST SOUNDINGS
WILL DRY OUT QUITE A BIT IN THE MORNING AS A DRY SLOT PUNCHES IN
FROM THE SOUTH... SUGGESTING A TRANSITION TO PATCHY DRIZZLE (OR
PERHAPS A LITTLE FREEZING DRIZZLE IN THE FAR NW CWA WHERE SURFACE
WET BULB TEMPS WILL BE DROPPING TO AROUND 32F) AS THE COLDER AIR
ARRIVES POST-FRONT... WITH THE LOWEST 4 KM OR SO STAYING SATURATED.
A SLUG OF DPVA ASSOCIATED WITH THE NORTHERN STREAM PORTION OF THE
MID LEVEL LONGWAVE TROUGH SWINGS THROUGH NW NC WED AFTERNOON
ATTENDING A DEFORMATION ZONE ALOFT... HOWEVER THESE TOO SHOULD BE
WEAKENING AND DON`T APPEAR TO PROVIDE ENOUGH DEEP LAYER LIFT TO RE-
SATURATE THE AIR ABOVE -10C. AS SUCH... BELIEVE THAT A FEW WET
FLAKES WILL BE POSSIBLE ACROSS THE NW AND FAR NRN PIEDMONT WED
AFTERNOON AS THE COLUMN COOLS... BUT IT SHOULD BE INCONSEQUENTIAL
GIVEN THE BRIEF WINDOW OF OPPORTUNITY AND LIMITED MOISTURE ALOFT.
PASSAGE OF A WEAK POST-FRONTAL SURFACE TROUGH WED AFTERNOON WILL
SWING WINDS AROUND TO A UNIFORMLY NW DIRECTION... YIELDING CLEARING
SKIES BY EARLY EVENING AS DOWNSLOPE FLOW AND DRY AIR ADVECTION TAKES
OVER. WITH A TIGHTENING MSLP GRADIENT DUE TO THE STRENGTHENING
DEPARTING SURFACE LOW... THESE BRISK NW WINDS DURING THE DAY ARE
EXPECTED TO TOP OUT AT 15-20 MPH SUSTAINED WITH GUSTS OVER 30 MPH
POSSIBLE AS STRONG 925 MB WINDS NEAR 35 KT MIX DOWN TO THE SURFACE.
WED HIGHS ARE APT TO BE VERY CLOSE TO THE MORNING LOWS... WITH
PLUNGING THICKNESSES THROUGH THE DAY WITH STEADY COLD AIR ADVECTION
CAUSING TEMPS TO FALL SLOWLY THROUGH THE DAY. EARLY DAY HIGHS FROM
THE UPPER 30S NW TO LOWER 60S IN THE EASTERN COASTAL PLAIN...
FALLING TO THE MID 30S NW TO MID 40S EAST BY LATE AFTERNOON. DEW
POINTS WILL FALL INTO THE TEENS TO LOWER 20S OVERNIGHT WITH CLEARING
SKIES... BUT THE CONTINUED LOW LEVEL MIXING WILL KEEP TEMPS FROM
FALLING TOO LOW... BUT STILL CHILLY WITH LOWS 22-28. LATE DAY WIND
CHILLS ARE EXPECTED TO FALL INTO THE 20S OVER THE PIEDMONT... AND
INTO THE TEENS TO AROUND 20 AREAWIDE WED NIGHT WITH DIMINISHING
WINDS.
FOR THU/THU NIGHT: THE CORE OF THE MID LEVEL TROUGH WILL BE WELL TO
OUR NE BY THU MORNING... ALTHOUGH BROAD FLAT TROUGHING WILL PERSIST
OVER THE EASTERN CONUS AS A VORTEX SPINS OFF CA WITH WEAK LONGWAVE
RIDGING IN BETWEEN. SURFACE HIGH PRESSURE WILL BUILD INTO THE AREA
FROM THE WSW AND DRIFT OVER THE SRN/CENTRAL APPALACHIANS AND MID-
ATLANTIC THROUGH THU NIGHT. EXPECT A DRY AND SUBSIDING COLUMN WITH
JUST A FEW HIGH CLOUDS AS ONE LAST WEAK PERTURBATION SWEEPS OVER THE
REGION. MAX TEMPS SHOULD BE COMPARABLE TO YESTERDAY GIVEN A SIMILAR
AIR MASS WITH SIMILAR (PERHAPS A BIT HIGHER) PREDICTED THICKNESSES.
HIGHS 38-45. MOSTLY CLEAR AND CONTINUED COLD THU NIGHT. LOWS 22-27
LOOK GOOD.
FOR FRI THROUGH MON: THE SRN STREAM PORTION OF THE SURFACE HIGH WILL
MERGE WITH THE POLAR HIGH TO BE CENTERED OVER MAINE/SW QUEBEC AND
NOSE TO THE SSW THROUGH CENTRAL NC FRI THROUGH SAT... AS THE MID
LEVEL FLOW OVER THE CENTRAL/ERN CONUS FLATTENS. AN INVERTED TROUGH
IS EXPECTED TO FORM ALONG THE SOUTHEAST COAST OVER THE WEEKEND...
AND THE ENHANCED ONSHORE-DIRECTED LOW LEVEL FLOW SHOULD PULL
INCREASING LOW LEVEL ATLANTIC MOISTURE INTO NC... RESULTING IN
INCREASING CLOUDS AS WE HEAD THROUGH SUNDAY. THE MID LEVEL LOW OFF
CA LATE IN THE WEEK OPENS UP AND WEAKENS THEN HEADS EASTWARD... AND
AS THIS BROAD TROUGH APPROACHES NC FROM THE WEST LATE SUN THROUGH
MON... EXPECT A TREND TO MOSTLY CLOUDY SKIES AND A CHANCE OF RAIN AS
THE OLD FRONT HEADS NORTHWARD TOWARD NC AS A WARM FRONT. EXPECT A
GRADUAL RECOVERY IN TEMPS THROUGH THIS PERIOD... STAYING BELOW
NORMAL HOWEVER. HIGHS IN THE 40S TO NEAR 50 FRI/SAT... CLIMBING TO
THE 50S TO NEAR 60 FOR SUN/MON. -GIH
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 115 AM TUESDAY...
24 HOUR TAF PERIOD:
THE MOST TREACHEROUS CONDITIONS FOR THE TAFS WILL BE IN THE TRIAD AS
A POTENT STORM SYSTEM MOVES IN FROM THE SOUTHWEST. NO RAIN OBSERVED
YET AT KINT AND KGSO DESPITE RADAR RETURNS ON THE 0.5 DEGREE
ELEVATION ANGLE. THIS IS OWING TO VERY DRY AIR IN THE LOWER LEVELS
WHICH WILL TAKE A WHILE TO OVERCOME BEFORE PRECIPITATION BEGINS IN
THE TRIAD. AS EVAPORATIVE COOLING OCCURS IN THE LOW LEVELS
TEMPERATURES WILL COOL TO NEAR FREEZING AND A PERIOD OF FREEZING
RAIN IS POSSIBLE AT KINT AND KGSO BEGINNING AROUND 9Z THROUGH 14Z OR
SO BEFORE WARM AIR ADVECTION CAUSES TEMPERATURES TO RECOVER. AT THIS
TIME FREEZING RAIN IS EXPECTED TO GIVE WAY TO AN EXTENDED PERIOD OF
LIGHT TO MODERATE RAIN...WITH POCKETS OF HEAVIER PRECIPITATION
THROUGH THE END OF THE TAF PERIOD. ALREADY MVFR CONDITIONS IN THE
TRIAD ARE EXPECTED TO FURTHER DETERIORATE TO IFR/LIFR AND MOST
LIKELY WILL REMAIN IN THE TANK THROUGH THE PERIOD WITH CEILINGS LESS
THAN 1000 FEET AND VISIBILITIES MAINLY IN THE MVFR RANGE.
CONDITIONS AT THE REMAINING TAF SITES WILL BE SIMILAR BUT WITHOUT
THE PERIOD OF FREEZING RAIN AT THE ONSET AS TEMPERATURES ARE
EXPECTED TO REMAIN ABOVE FREEZING THROUGH THE PERIOD. ANOTHER
CONCERN AT ALL TAF LOCATIONS WILL BE LOW LEVEL WIND SHEAR THAT IS
EXPECTED TO PICK UP JUST AFTER SUNRISE...NEAR 14Z. LIGHT EAST OR
NORTHEASTERLY WINDS IN THE LOW LEVELS WILL RAPIDLY INCREASE TO 35 TO
40 KNOTS OUT OF THE SOUTHEAST NEAR 2 KFT. WHILE THE SEVERITY OF THE
LLWS WILL DECREASE AFTER 00Z WEDNESDAY...LLWS WILL STILL BE A
CONCERN THROUGH THE END OF THE TAF PERIOD WITH THE EXCEPTION OF KRWI
WHERE THE THREAT WILL END EARLIER AS SURFACE WINDS SHOULD BE
STRONGER AND NEAR UNIDIRECTIONAL TO HELP MITIGATE SHEAR POTENTIAL.
LONG TERM: A SECOND STORM SYSTEM WILL FOLLOW RIGHT BEHIND THE FIRST
WHICH WILL CARRY INTO WEDNESDAY BEFORE CLEARING OUT WEDNESDAY NIGHT.
CONDITIONS SHOULD BE PREDOMINATELY VFR THEREAFTER UNTIL EARLY NEXT
WEEK WHEN THE NEXT SYSTEM APPROACHES.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR NCZ007-
021>024-038-039.
&&
$$
SYNOPSIS...WSS
NEAR TERM...BSD
SHORT TERM...WSS
LONG TERM...HARTFIELD
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
924 PM CST WED NOV 27 2013
.UPDATE...
ISSUED AT 924 PM CST WED NOV 27 2013
LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS CONTINUE TO SHOW
WESTERN AND CENTRAL NORTH DAKOTA INUNDATED WITH STRATUS. ISOLATED
FLURRIES CONTINUE IN THE NORTH. ONLY ADJUSTMENT WAS TO RAISE
OVERNIGHT TEMPERATURES BETWEEN 3 AND 5 DEGREES DUE TO THE CLOUDS
AND MIXED BOUNDARY LAYER/BRISK WINDS. LATEST NAM AND RAP13 SHOWS
THE STRATUS CONTINUING THROUGH 18Z THURSDAY...AND POSSIBLY INTO
THE AFTERNOON.
UPDATE ISSUED AT 556 PM CST WED NOV 27 2013
MAIN UPDATE THIS EVENING WAS TO INCREASE SKY GRIDS TO 100 PERCENT
OVER MOST OF WESTERN AND CENTRAL NORTH DAKOTA. LATEST FOG/STRATUS
LOOP IN CONJUNCTION WITH THE RAP13 AND HRRR 925MB-H85 RH FIELD...ARE
VERIFYING WELL AND ARE IN GOOD AGREEMENT TONIGHT. THE STRATUS WILL
MAKE IT TO THE SOUTHERN BORDER IN THE NEXT FEW HOURS AS WELL AS
INTO THE JAMES RIVER VALLEY. EXPECT OVERCAST CONDITIONS WITH ISOLATED
FLURRIES TONIGHT INTO MID MORNING THURSDAY BEFORE SKY IMPROVEMENTS
BEGIN. REST OF FORECAST IS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 352 PM CST WED NOV 27 2013
THE TEMPERATURE ROLLER COASTER WILL CONTINUE TONIGHT AND THURSDAY
AS ANOTHER SHOT OF COLD CANADIAN AIR PUSHES SOUTH INTO NORTH
DAKOTA. LOW STRATUS HAS ADVANCED INTO FAR NORTHWEST ND DURING THE
EARLY AFTERNOON...AND WILL CONTINUE A SOUTHWARD PUSH...ACCOMPANIED
BY A FEW FLURRIES. EXPECT ANOTHER NIGHT OF LOWS IN THE SINGLE
DIGITS TO TEENS SOUTHWEST.
ON THANKSGIVING DAY...HIGH PRESSURE WILL DRIFT INTO EASTERN
NORTH DAKOTA ON THURSDAY...SETTING UP ANOTHER NE-SW TEMPERATURE
GRADIENT. HIGHS ARE FORECAST IN THE MID TEENS NEAR THE TURTLE
MOUNTAINS...LOW TO MID 20S NEAR BISMARCK/MANDAN...AND NEAR 30 AT BOWMAN.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 352 PM CST WED NOV 27 2013
POTENTIAL MAJOR WINTER STORM NEXT WEEK.
THE MAIN FOCUS THROUGH THE EXTENDED PERIOD IS ON A POTENTIAL
WINTER STORM THAT MAY IMPACT THE REGION SUNDAY THROUGH THURSDAY.
AT THIS TIME THERE IS A LOT OF UNCERTAINTY AS TO
TIMING...PLACEMENT AND AMOUNTS. MODEL RUNS HAVE SLOWLY COME INTO
BETTER AGREEMENT OVER THE PAST RUN...BUT THERE ARE STILL LARGE
DISCREPANCIES THAT NEED TO BE RESOLVED BEFORE CONFIDENCE CLIMBS
HIGH ENOUGH TO WARRANT ANY THOUGHT OF WINTER WEATHER HEADLINES.
THE 12 UTC HAS THE POLAR AND SUBTROPICAL JETS PHASING TOGETHER LATE
NEXT WEEK AS A VERY POTENT LONGWAVE TROUGH DIGS SOUTH ACROSS THE
MOUNTAIN WEST. THIS WOULD SET UP VERY STRONG CYCLOGENESIS ACROSS
THE PLAINS. THE ECMWF IS STRONGER AND DEEPER WITH THIS TROUGH AND
CYCLOGENESIS AND THEREFORE FURTHER SOUTH AND SLIGHTLY SLOWER THAN
THE GFS. THE 12 UTC GFS MAINTAINS SPLIT FLOW UNTIL THE VERY END OF
NEXT WEEK AND DEVELOPS MORE OF A PROGRESSIVE OPEN WAVE. THIS WOULD
TEND TO FAVOR A QUICKER AND FURTHER NORTH SOLUTION.
ONE THING THAT IS MORE CERTAIN IS THE INTRUSION OF COLD AIR. A
VERY COLD AIRMASS IS SETTING UP ACROSS EASTERN SIBERIA AND IS
PROGGED TO ENTER EASTERN ALASKA AND FROM THERE MAKE A BEELINE
TOWARD THE CENTRAL CONTINENTAL USA. THIS COULD POTENTIALLY BE THE
COLDEST AIR WE HAVE SEEN YET WITH 850MB TEMPS AROUND -25.
UNTIL LATE SUNDAY TEMPERATURES SHOULD BE MILD AND AND PRECIP
CHANCES MINIMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 556 PM CST WED NOV 27 2013
LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW MVFR TO IFR
CIGS EXPANDING TOWARD THE SOUTHERN BORDER THIS EVENING. EXPECT ALL
AERODROMES TO FALL UNDER THESE CONDITIONS UNTIL 15Z TO 18Z
THURSDAY...WHEN CIGS WILL BEGIN TO LIFT AND IMPROVE TO VFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...RK
LONG TERM...AJ
AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
556 PM CST WED NOV 27 2013
.UPDATE...
ISSUED AT 556 PM CST WED NOV 27 2013
MAIN UPDATE THIS EVENING WAS TO INCREASE SKY GRIDS TO 100 PERCENT
OVER MOST OF WESTERN AND CENTRAL NORTH DAKOTA. LATEST FOG/STRATUS
LOOP IN CONJUNCTION WITH THE RAP13 AND HRRR 925MB-H85 RH FIELD...ARE
VERIFYING WELL AND ARE IN GOOD AGREEMENT TONIGHT. THE STRATUS WILL
MAKE IT TO THE SOUTHERN BORDER IN THE NEXT FEW HOURS AS WELL AS
INTO THE JAMES RIVER VALLEY. EXPECT OVERCAST CONDITIONS WITH ISOLATED
FLURRIES TONIGHT INTO MID MORNING THURSDAY BEFORE SKY IMPROVEMENTS
BEGIN. REST OF FORECAST IS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 352 PM CST WED NOV 27 2013
THE TEMPERATURE ROLLER COASTER WILL CONTINUE TONIGHT AND THURSDAY
AS ANOTHER SHOT OF COLD CANADIAN AIR PUSHES SOUTH INTO NORTH
DAKOTA. LOW STRATUS HAS ADVANCED INTO FAR NORTHWEST ND DURING THE
EARLY AFTERNOON...AND WILL CONTINUE A SOUTHWARD PUSH...ACCOMPANIED
BY A FEW FLURRIES. EXPECT ANOTHER NIGHT OF LOWS IN THE SINGLE
DIGITS TO TEENS SOUTHWEST.
ON THANKSGIVING DAY...HIGH PRESSURE WILL DRIFT INTO EASTERN
NORTH DAKOTA ON THURSDAY...SETTING UP ANOTHER NE-SW TEMPERATURE
GRADIENT. HIGHS ARE FORECAST IN THE MID TEENS NEAR THE TURTLE
MOUNTAINS...LOW TO MID 20S NEAR BISMARCK/MANDAN...AND NEAR 30 AT BOWMAN.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 352 PM CST WED NOV 27 2013
POTENTIAL MAJOR WINTER STORM NEXT WEEK.
THE MAIN FOCUS THROUGH THE EXTENDED PERIOD IS ON A POTENTIAL
WINTER STORM THAT MAY IMPACT THE REGION SUNDAY THROUGH THURSDAY.
AT THIS TIME THERE IS A LOT OF UNCERTAINTY AS TO
TIMING...PLACEMENT AND AMOUNTS. MODEL RUNS HAVE SLOWLY COME INTO
BETTER AGREEMENT OVER THE PAST RUN...BUT THERE ARE STILL LARGE
DISCREPANCIES THAT NEED TO BE RESOLVED BEFORE CONFIDENCE CLIMBS
HIGH ENOUGH TO WARRANT ANY THOUGHT OF WINTER WEATHER HEADLINES.
THE 12 UTC HAS THE POLAR AND SUBTROPICAL JETS PHASING TOGETHER LATE
NEXT WEEK AS A VERY POTENT LONGWAVE TROUGH DIGS SOUTH ACROSS THE
MOUNTAIN WEST. THIS WOULD SET UP VERY STRONG CYCLOGENESIS ACROSS
THE PLAINS. THE ECMWF IS STRONGER AND DEEPER WITH THIS TROUGH AND
CYCLOGENESIS AND THEREFORE FURTHER SOUTH AND SLIGHTLY SLOWER THAN
THE GFS. THE 12 UTC GFS MAINTAINS SPLIT FLOW UNTIL THE VERY END OF
NEXT WEEK AND DEVELOPS MORE OF A PROGRESSIVE OPEN WAVE. THIS WOULD
TEND TO FAVOR A QUICKER AND FURTHER NORTH SOLUTION.
ONE THING THAT IS MORE CERTAIN IS THE INTRUSION OF COLD AIR. A
VERY COLD AIRMASS IS SETTING UP ACROSS EASTERN SIBERIA AND IS
PROGGED TO ENTER EASTERN ALASKA AND FROM THERE MAKE A BEELINE
TOWARD THE CENTRAL CONTINENTAL USA. THIS COULD POTENTIALLY BE THE
COLDEST AIR WE HAVE SEEN YET WITH 850MB TEMPS AROUND -25.
UNTIL LATE SUNDAY TEMPERATURES SHOULD BE MILD AND AND PRECIP
CHANCES MINIMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 556 PM CST WED NOV 27 2013
LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW MVFR TO IFR
CIGS EXPANDING TOWARD THE SOUTHERN BORDER THIS EVENING. EXPECT ALL
AERODROMES TO FALL UNDER THESE CONDITIONS UNTIL 15Z TO 18Z
THURSDAY...WHEN CIGS WILL BEGIN TO LIFT AND IMPROVE TO VFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...RK
LONG TERM...AJ
AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1240 AM CST TUE NOV 26 2013
.UPDATE...
ISSUED AT 1240 AM CST TUE NOV 26 2013
NO MAJOR UPDATES REQUIRED TO THE FORECAST FOR THE OVERNIGHT HOURS.
ADDED A MENTION OF FLURRIES WESTWARD TO INCLUDE NEARLY ALL OF
CENTRAL NORTH DAKOTA TO THE JAMES RIVER BASIN FOR THE OVERNIGHT
HOURS. MINIMUM TEMPERATURES WILL DEPEND GREATLY ON SKY COVER WITH
CLEAR SKIES ALLOWING RADIATIONAL COOLING AND CLOUD COVER KEEPING
TEMPERATURES STEADY OR PERHAPS RISING A TAD. EXPECTING VARIABLE
CLOUDINESS OVERNIGHT...AND SOME AREAS INDICATED NEARLY REACHING
THE FORECAST MIN TEMPERATURES IN CLEAR SKIES. LOWERED MIN TEMPS
JUST A TAD TO ACCOUNT FOR PATCHY CLOUDS/CLEARING.
UPDATE ISSUED AT 958 PM CST MON NOV 25 2013
NO MAJOR UPDATES WERE REQUIRED TO THE ONGOING FORECAST. ONLY
ADJUSTED THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT
OBS/TRENDS. THE UPDATED PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 707 PM CST MON NOV 25 2013
LOW CLOUDS WILL CONTINUE PRIMARILY ALONG AND EAST OF THE MISSOURI
RIVER TONIGHT. FURTHERMORE...BOUNDARY LAYER WINDS ARE
FORECAST TO REMAIN AROUND 30 KNOTS EAST OF HIGHWAY 83 THROUGH 12Z
TUESDAY. GIVEN THE COMBINATION OF LOW CLOUDS AND TURBULENT
BOUNDARY LAYER FLOW...ADJUSTED OVERNIGHT LOWS UP BY TWO
CATEGORIES...MAINLY EAST OF HIGHWAY 83. HIGH PRESSURE NOSING INTO
WESTERN NORTH DAKOTA WILL LIKELY CLEAR OUT THE CLOUDS WEST AFTER
MIDNIGHT AND ALLOW TEMPERATURES TO RADIATE INTO THE SINGLE DIGITS
WEST OF HIGHWAY 85 BY TUESDAY MORNING.
THE REMAINING FORECAST ELEMENTS ARE IN GOOD SHAPE. THE UPDATED
PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 320 PM CST MON NOV 25 2013
A STRONGER SURGE OF COLD AIR ADVECTION WILL PUSH SOUTH INTO NORTH
DAKOTA OVERNIGHT. AFTERNOON OBS AND REFLECTIVITY NEAR ROLLA...AND
LIGHT QPF SCATTERED ALONG THE EASTERN FRINGES OF THE FORECAST AREA
IN SOME SHORT RANGE MODELS...HAVE PROMPTED INCLUSION OF FLURRIES
FROM THE TURTLE MOUNTAINS THROUGH THE JAMES RIVER VALLEY TONIGHT.
A FEW AFTERNOON OBS AT MINOT AND TIOGA...SUGGESTIVE OF FREEZING
DRIZZLE/UNKNOWN PRECIP...ARE ACTUALLY THE RESULT OF EXISTING SNOW
BEING BLOWN NEAR THE WEATHER SENSOR.
HAVE INCREASED OVERNIGHT CLOUD COVER BASED ON AFTERNOON TRENDS AND
ROBUST LOW LEVEL RH EVIDENT ON THE RAP MODEL. LOWS SHOULD BE IN THE
SINGLE DIGITS TO AROUND 10 DEGREES SOUTH. TUESDAY WILL BE THE
COLDEST DAY OF THE COMING WEEK...WITH HIGHS IN THE TEENS TO LOWER
20S SOUTHWEST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 320 PM CST MON NOV 25 2013
LATEST EXTENDED SUITE CONTINUES TO SHOW AN ACTIVE PERIOD IN TERMS
OF SUCCESSIVE DRY FRONTAL SYSTEMS SLIDING THROUGH. THE NEXT
POTENTIALLY SIGNIFICANT SYSTEM MAY OCCUR MONDAY AND BEYOND.
A PROGRESSIVE PATTERN BEGINS THE LONG TERM WITH A WAVERING
BAROCLINIC ZONE SHIFTING FROM WEST TO EAST TUESDAY NIGHT AS WARM AIR
ADVECTION COMMENCES. A WEAK COLD FRONT FOLLOWS FOR WEDNESDAY/
WEDNESDAY NIGHT WITH A RETURN TO COLD AIR ADVECTION INTO EARLY
THURSDAY. NEUTRAL ADVECTION TO WEAK WARM AIR ADVECTION RESUMES
FRIDAY INTO SATURDAY. THE ONLY SUFFICIENT LIFT FOR MEASURABLE
PRECIPITATION DURING THIS TIME WOULD BE CONFINED TO THE TURTLE
MOUNTAINS WEDNESDAY AND FRIDAY NIGHT. HAVE COLLABORATED WITH OUR
EASTERN OFFICE AND INCORPORATED A SLIGHT CHC OF SNOW IN THE FAR
NORTHEAST. ANY SNOW ACCUMULATION WOULD BE MINIMAL AT BEST.
THE NEXT SYSTEM TO AFFECT WESTERN AND CENTRAL NORTH DAKOTA SHOWS
SIGNS OF LIGHT PRECIPITATION BREAKING OUT VIA WARM AIR ADVECTION
PROCESSES SUNDAY AFTERNOON INTO SUNDAY NIGHT. HOWEVER IT APPEARS
THE BULK OF PRECIPITATION WOULD BE IN THE FORM OF SNOW MONDAY INTO
MONDAY NIGHT. A DRY SLOT MAY FOLLOW FOR TUESDAY. STILL A LOT OF
UNCERTAINTY THIS FAR OUT AND WILL CONTINUE TO MONITOR FUTURE
MODELS RUNS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1240 AM CST TUE NOV 26 2013
MVFR CIGS WILL CONTINUE GENERALLY ALONG AND EAST OF A LINE FROM
KISN-KBIS TONIGHT. CONDITIONS WILL GRADUALLY IMPROVE TO VFR FROM
WEST TO EAST TUESDAY MORNING. VFR CONDITIONS ARE FORECAST OVER
KISN/KDIK/KMOT/KBIS BY TUESDAY AFTERNOON...AND AT KJMS LATE
AFTERNOON. NORTHWEST WINDS WILL CONTINUE THROUGH TUESDAY
AFTERNOON...THEN BECOME LIGHT AND TURN TO THE SOUTHEAST BY/DURING
TUESDAY EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...RP KINNEY
LONG TERM...KS
AVIATION...JV
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
1121 PM CST MON NOV 25 2013
.UPDATE...
06Z AVIATION DISCUSSION BELOW.
.PREVIOUS UPDATE DISCUSSION...
STRATUS SHIELD CONTS TO SLIDE SE ACROSS NERN PART OF SOUTH DAKOTA
OVERNIGHT...CREATING A DIFFICULT FORECAST FOR OVERNIGHT LOWS.
TEMPS UNDER THE CLOUD SHIELD HAVE NOT FALLEN OFF GREATLY FROM THE
AFTERNOON READINGS...WITH TEMPS AOA 30 DEGREES AND HOLDING STEADY.
FURTHER SW...CLEAR SKIES ARE ENABLING TEMPS IN THE FAR SW CWA TO
FALL...ALBEIT SLOWLY...BUT FALLING NONE THE LESS. THE PROBLEM
ARISES WHEN TRYING TO TIME THE BACK EDGE OF THE CLOUD SHIELD AS IT
HAS PUSHED INTO NRN ND ATTM WITH TEMPS ACROSS SRN CANADA IN THE
SINGLE DIGITS ABOVE ZERO. SENT OUT EARLIER UPDATE TO SLOW THE TEMP
FALL ACROSS THE CWA...AND RAISE LOWS ABOUT A CATEGORY ACROSS THE
NE. ALSO MANUALLY ADJUSTED THE HOURLY TEMP GRIDS...KEEPING TEMPS
UP THROUGH 10Z OR SO...THEN IN ANTICIPATION OF CLEARING
LINE...ALLOWED TEMPS TO FALL TO FORECAST LOWS AROUND 13Z TO 14Z.
ISOLD FLURRIES ARE STILL BEING REPORTED ACROSS ERN SECTIONS OF
ND...AND STILL SEEMS PRUDENT TO KEEP THEM IN ONGOING FCST. ALSO
TWEAKED SKY GRIDS TO BETTER MATCH CURRENT CLOUD SHIELD LOCATION
AND WINDS ARE ALSO STAYING UP JUST A BIT. UPDATED ZONE FORECAST
SENT OUT EARLIER.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
LEADING EDGE OF THE STRATUS/STRATOCUMULUS DECK IS FIRMLY IN PLACE
ACROSS THE EASTERN CWA...WITH A MASSIVE EXPANSION BACK TO THE
NORTH INTO CANADA. MAIN FORECAST ISSUES OVERNIGHT WILL BE CLOUD
COVER AND THE ONSET OF STRONGER COLD AIR ADVECTION. RUC13 900-850
MB RH HAS A VERY GOOD HANDLE ON CURRENT STRATUS OVER THE REGION SO
USED THAT AS A FORECAST FOR THE OVERNIGHT PERIOD. IT BASICALLY
SHOWS THE STRATUS SLOWLY OOZING SOUTHWEST ACROSS SOUTH DAKOTA
THROUGH 12Z TUESDAY. HAVE INCREASED SKY COVER FROM PREVIOUS
FORECAST AND MAY NEED TO BE BEEFED UP MORE FOR EVENING UPDATES.
WITH ADDITIONAL WEAK SHORTWAVE ENERGY MOVING SOUTH OVER THE AREA
LATE TONIGHT AND THE STRONGER COLD AIR ADVECTION...SEE NO REASON
WHY CLOUDS WOULD BREAK UP OR CEASE TO MOVE ANY FURTHER
SOUTH/SOUTHWEST INTO TUESDAY MORNING. LEFT IN THE MENTION OF
FLURRIES FOR THE EASTERN CWA LATE TONIGHT THROUGH TUESDAY MORNING
IN ASSOCIATION WITH THE WEAK SHORTWAVE ENERGY. CURRENT OBS ACROSS
NORTHEAST ND AND SOUTHERN CANADA SHOW -SN WITH VSBYS GENERALLY
ABOVE 6SM IN ASSOCIATION WITH THE WEAK WAVE. WITH THE ONSET OF
COLDER AIR ALOFT ON TUESDAY...WILL SEE HIGH TEMPS SEVERAL DEGREES
COLDER THAN MONDAY. READINGS WILL BE IN THE TEENS TO MID 20S
ACROSS THE CWA. SURFACE HIGH THEN MOVES THROUGH THE AREA TUESDAY
NIGHT WHICH SHOULD CLEAR THE SKIES AND PROVIDE FOR A PERIOD OF
LIGHT WINDS. ALTHOUGH THE RIDGE AXIS IS PRETTY NARROW AND A QUICK
MOVER...SO BY 12Z WEDNESDAY MUCH OF THE CWA IS ALREADY UNDER
SOUTHERLY SFC WIND FLOW. NOT AN IDEAL RADIATIONAL COOLING
SETUP...BUT WILL STILL GET PRETTY COLD NONETHELESS. WILL BE AROUND
0 DEGREES ACROSS THE EASTERN CWA WITH FAVORED COLD SPOTS PERHAPS
SNEAKING BELOW ZERO. HIGHS ON WEDNESDAY WILL REBOUND SOMEWHAT AS
925MB TEMPS BEGIN TO WARM ON THE BACKSIDE OF THE RETREATING SFC
HIGH. BREEZY WINDS WILL DEVELOP SO THERE WILL BE DECENT MIXING.
HIGHS WILL REMAIN BELOW NORMAL THOUGH AS THE OVERALL PATTERN
REMAINS COLD.
.LONG TERM...THURSDAY THROUGH SUNDAY
NORTHWEST FLOW ALOFT WILL BE THE PREDOMINATE UPPER PATTERN
THROUGH MOST OF THE LONG TERM PERIOD...BUT A PATTERN CHANGE
DOES SEEM TO BE ON THE HORIZON. A SHORTWAVE TROUGH DROPPING OUT
OF CANADA WILL INFLUENCE THE REGION FOR THE FRIDAY/SATURDAY TIME
FRAME...HOWEVER MOST OF THE FORCING APPEARS TO REMAIN NORTH OF OUR
CWA...AND MODEL MOISTURE PROFILES REMAIN FAIRLY DRY AT THIS POINT.
DECENT WARM AIR ADVECTION AHEAD OF THAT WAVE COULD CAUSE SOME
PTYPE ISSUES IF PRECIPITATION WERE TO MATERIALIZE OVER OUR CWA
SATURDAY. ALTHOUGH MODELS VARY ON THE STRENGTH OF THE WARM
PUSH...850 MB TEMPERATURES DO RISE ABOVE 0 C...WITH THE GFS
ADVERTISING AS HIGH AS 6 OR 7 C ACROSS OUR SOUTHERN CWA.
EITHER WAY...CONTINUED WITH THE DRY ALLBLEND FORECAST FOR NOW. BY
SUNDAY WEAK RIDING APPEARS TO BE OVER THE NORTHERN PLAINS...BUT
IT ONLY PRECEDES A MORE SIGNIFICANT UPPER LOW MOVING INTO THE
PACIFIC NORTHWEST.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
MVFR STRATUS DECK CONTS TO RESIDE OVER THE NERN PART OF THE
CWA...WITH KMBG/KABR/KATY ALL REPORTING OVC CONDS. LOOK FOR THE
EDGE OF THE SHIELD TO CREATE SCT-BKN CONDS FOR THE KPIR TERMINAL
BY 08Z. BACK EDGE OF CLOUD DECK LOOKS TO MOVE INTO THE NRN
TERMINAL LOCATIONS AOA 13Z...AND INTO KATY BY 15Z. GUSTY NW WINDS
WILL WILL AFFECT ALL TERMINAL LOCATIONS THROUGH 14Z BEFORE
BEGINNING TO DIMINISH. ONCE SKIES CLEAR...LOOK FOR GOOD VFR CONDS
THROUGH THE REMAINDER OF THE VALID FORECAST PERIOD.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...HINTZ
SHORT TERM...TMT
LONG TERM...SERR
AVIATION...HINTZ
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1215 PM CST TUE NOV 26 2013
.DISCUSSION...
18Z AVIATION DISCUSSION.
&&
.AVIATION...
INTERESTING FORECAST THIS MORNING AS A COLD UPPER LOW DIGS DOWN
OVER THE EASTERN TEXAS/COASTAL BEND THROUGH THE DAY. THE ATMOSPHERIC
COLUMN BEGINS TO DRY THROUGH LATE AFTERNOON/EARLY EVENING...BUT
THAT WINDOW BETWEEN WHERE THERE IS JUST ENOUGH MOISTURE (OR ICE
CRYSTAL NUCLEI) IN TANDEM WITHIN ANY SUB-FREEZING LAYER OF ANY
SIGNIFICANT THICKNESS...WILL BE THE DETERMINING FACTOR AS TO
WHETHER NORTHERN HUB RECEIVE A RAIN-SNOW MIXTURE THROUGH THE
EARLY AFTERNOON. AS OF NOW...THE THERMODYNAMIC NATURE OF THE
PROGGED PROFILES OVER THE FAR NORTHERN HUBS COULD SUPPORT THIS
SCENARIO AS THE UPPER LOW PASSES BY. THE BEST CHANCE FOR ANY
FROZEN PRECIPITATION FOR SUCH HUBS AS KUTS OR KCXO WILL BE BY LATE
AFTERNOON AND WOULD BE IN MIXED FORM...LIGHT RAIN OR DRIZZLE WITH
EITHER SNOW OR ICE PELLETS. THIS COULD TEMPORARILY TURN OVER TO
ALL SNOW OVER THE EXTREME NORTHERN TERMINALS (KUTS). A LOW FREEZING
LINE...AND A FAIRLY-SATURATED BELOW FREEZING COLUMN UP THROUGH
THE UPPER ATMOSPHERE DUE TO WRAP-AROUND MOISTURE...MAKES FOR A
HIGHER POTENTIAL FOR AIRCRAFT ICE RIMING THROUGH THIS EVENING.
AS THE UPPER LOW EXITS EAST...DECKS WILL GRADUALLY LIFT TO MVFR
THROUGH EARLY EVENING TO MAINLY SKY CLEAR/SCT250 BY MIDNIGHT. A
VERY TIGHT OFFSHORE PRESSURE GRADIENT WILL MAKE FOR MODERATE
NORTHWESTERN INTERIOR WINDS...STRONG ALONG THE IMMEDIATE COAST
THROUGH THE PERIOD. 31
&&
.PREV DISCUSSION... /ISSUED 1006 AM CST TUE NOV 26 2013/
UPDATE...
SEE MORNING UPDATE.
DISCUSSION...
12Z DATA SHOWS THE UPPER LEVEL TROUGH AXIS STILL TO THE WEST WITH
SOME WEAK DIVERGENCE NOTED OVER EAST TEXAS. MOISTURE STILL LOOKS
RATHER PLENTIFUL AT 850 AND 700 MB. THE FREEZING LINE AT 850 MB
EXTENDS ACROSS THE WESTERN HALF OF SE TX. SHORT TERM GUIDANCE
SUGGESTS THAT MSTR WILL LINGER A BIT LONGER THAN EXPECTED
YESTERDAY AND FORCING FROM THE UPPER TROUGH SHOULD CONTINUE TO
FOSTER PERIODS OF LIGHT RAIN THROUGH EARLY AFTN. WILL BUMP POPS TO
HIGH END CHANCE FOR THE EASTERN HALF OF THE CWA. RAP AND 12Z NAM
12 SOUNDINGS SUGGEST SOME POTENTIAL FOR WINTER PRECIP OVER THE NE
QUARTER OF THE CWA. SOUNDINGS LOOK COLD ENOUGH FOR SNOW AROUND 18Z
FROM CROCKETT TO LIVINGSTON. NOT SURE HOW COLD MID LEVEL AIR WILL
BE BUT ADDED A RAIN/SNOW MIX FOR THE NE PART OF THE AREA. SURFACE
TEMPS WILL REMAIN TOO WARM FOR ANYTHING TO ACCUMULATE. NEW ZONES
OUT BY 1030 AM. 43
&&
PREV DISCUSSION... /ISSUED 434 AM CST TUE NOV 26 2013/
DISCUSSION...
THE LARGE AREA OF PRECIPITATION THAT HAS LINGERED ACROSS SOUTHEAST
TEXAS SINCE EARLY MONDAY IS BEGINNING TO SHIFT OFF TO THE EAST
WITH THE APPROACH OF THE MAIN UPPER LEVEL LOW. THIS SYSTEM IS
DIGGING SOUTHWARD ACROSS THE SOUTH PLAINS AND APPROACHING THE HILL
COUNTRY THIS MORNING. OF GREATEST CONCERN THIS MORNING IS THE
POTENTIAL FOR SOME WINTRY PRECIPITATION TO MIX IN WITH THE RAIN AS
THE LOW BRINGS COOLER TEMPERATURES ALOFT INTO THE REGION. A 09Z
SOUNDING FROM COLLEGE STATION SHOWS A WARM NOSE AT 800MB WITH A
WARM LAYER OF APPROXIMATELY 3KFT. BELOW THIS LAYER TEMPERATURES
FALL BACK BELOW FREEZING FOR 3KFT BEFORE RISING ABOVE FREEZING
AGAIN IN THE LAST 800 FEET. THIS SUPPORTS THE CURRENT FORECAST
REASONING WHICH IS FOR RAIN WITH SOME SLIGHT CHANCE FOR SLEET
MIXED IN ALONG AND NORTH OF A LINE FROM CALDWELL TO LIVINGSTON.
WITH SURFACE TEMPERATURES IN THE UPPER 30S NO ACCUMULATION IS
EXPECTED ACROSS THIS AREA. FURTHER SOUTH...PRECIPITATION WILL
REMAIN AS RAIN. AS THE MAIN UPPER LOW APPROACHES WE COULD BRIEFLY
SEE THE POTENTIAL FOR A FEW SNOW FLURRIES TO MIX IN WITH THE RAIN
AS TEMPERATURES ALOFT BEGIN TO COOL...BUT THIS IS NOT LIKELY TO
OCCUR BEFORE THE MOISTURE SHIFTS OFF TO OUR EAST AND PRECIPITATION
ENDS ACROSS THE REGION.
THE UPPER LOW WILL CROSS THE REGION TODAY BRINGING DRIER AND
COOLER AIR IN ITS WAKE. UNSEASONABLY COLD TEMPERATURES ARE
EXPECTED WEDNESDAY AND THURSDAY MORNINGS WITH A LIGHT FREEZE
EXPECTED ACROSS THE NORTHERN HALF OF THE REGION. A SLOW WARMING
TREND WILL BEGIN LATE IN THE WEEK THROUGH THE WEEKEND AS HIGH
PRESSURE EXITS THE REGION AND ONSHORE FLOW RESUMES. NEXT CHANCE
FOR RAIN WILL BE LATE THIS WEEKEND AS A WEAK DISTURBANCE MOVES
ACROSS THE REGION. 38
&&
MARINE...
STRONG NORTH TO NORTHWEST WINDS AND ROUGH SEAS WILL CONTINUE THROUGH
TONIGHT AS AN INTENSE UPPER LEVEL LOW PRESSURE SYSTEM MOVES THROUGH
THE UPPER TEXAS COASTAL WATERS. SMALL CRAFT ADVISORIES REMAIN IN
EFFECT...AND WIND GUSTS TO GALE FORCE WILL BE POSSIBLE. CONDITIONS
WILL BEGIN TO IMPROVE ON WEDNESDAY AS SURFACE HIGH PRESSURE BUILDS
INTO THE AREA...WINDS TURN TO THE NORTHEAST...AND SEAS COME DOWN.
LIGHT TO MODERATE NORTHEAST TO EAST WINDS ARE ANTICIPATED BEGINNING
ON THURSDAY AND CONTINUING INTO EARLY SATURDAY. A STRENGTHENING
ONSHORE FLOW IS IN THE FORECAST FOR THE END OF THE WEEKEND. 42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 30 48 29 54 35 / 10 0 0 0 0
HOUSTON (IAH) 32 51 30 57 37 / 10 0 0 0 0
GALVESTON (GLS) 42 50 42 57 50 / 10 0 0 0 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: BRAZORIA...CHAMBERS...GALVESTON...JACKSON...
MATAGORDA.
GM...SMALL CRAFT ADVISORY UNTIL 6 AM CST WEDNESDAY FOR THE FOLLOWING
ZONES: GALVESTON BAY...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...WATERS
FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...43
AVIATION/MARINE...31
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1006 AM CST TUE NOV 26 2013
.UPDATE...
SEE MORNING UPDATE.
&&
.DISCUSSION...
12Z DATA SHOWS THE UPPER LEVEL TROUGH AXIS STILL TO THE WEST WITH
SOME WEAK DIVERGENCE NOTED OVER EAST TEXAS. MOISTURE STILL LOOKS
RATHER PLENTIFUL AT 850 AND 700 MB. THE FREEZING LINE AT 850 MB
EXTENDS ACROSS THE WESTERN HALF OF SE TX. SHORT TERM GUIDANCE
SUGGESTS THAT MSTR WILL LINGER A BIT LONGER THAN EXPECTED
YESTERDAY AND FORCING FROM THE UPPER TROUGH SHOULD CONTINUE TO
FOSTER PERIODS OF LIGHT RAIN THROUGH EARLY AFTN. WILL BUMP POPS TO
HIGH END CHANCE FOR THE EASTERN HALF OF THE CWA. RAP AND 12Z NAM
12 SOUNDINGS SUGGEST SOME POTENTIAL FOR WINTER PRECIP OVER THE NE
QUARTER OF THE CWA. SOUNDINGS LOOK COLD ENOUGH FOR SNOW AROUND 18Z
FROM CROCKETT TO LIVINGSTON. NOT SURE HOW COLD MID LEVEL AIR WILL
BE BUT ADDED A RAIN/SNOW MIX FOR THE NE PART OF THE AREA. SURFACE
TEMPS WILL REMAIN TOO WARM FOR ANYTHING TO ACCUMULATE. NEW ZONES
OUT BY 1030 AM. 43
&&
.PREV DISCUSSION... /ISSUED 555 AM CST TUE NOV 26 2013/
AVIATION...
CURRENT BATCH OF -RA/RA WILL BE EAST OF OUR TAF SITES BY AROUND 14Z.
AS THE UPPER LOW CENTER MOVES ACROSS THE AREA LATER THIS MORNING THROUGH
THIS AFTERNOON...SOME HIGH RES MODELS ARE INDICATING POSSIBLE ADDITIONAL
DEVELOPMENT...ESPECIALLY BETWEEN IAH AND GLS. WILL COVER THIS CHANCE
WITH TEMPO FOR IAH AND PREVAILING FURTHER TO THE SOUTH. MVFR/IFR CEILINGS
THIS MORNING WILL BEGIN TO LIFT LATER THIS AFTERNOON WITH VFR CONDITIONS
ANTICIPATED THIS EVENING. WINDS WILL REMAIN ELEVATED FOR MUCH OF THE
DAY...ESPECIALLY NEAR THE COAST...THEN COME DOWN THIS EVENING UNDER
A RELAXING PRESSURE GRADIENT.
42
PREV DISCUSSION... /ISSUED 434 AM CST TUE NOV 26 2013/
DISCUSSION...
THE LARGE AREA OF PRECIPITATION THAT HAS LINGERED ACROSS SOUTHEAST
TEXAS SINCE EARLY MONDAY IS BEGINNING TO SHIFT OFF TO THE EAST
WITH THE APPROACH OF THE MAIN UPPER LEVEL LOW. THIS SYSTEM IS
DIGGING SOUTHWARD ACROSS THE SOUTH PLAINS AND APPROACHING THE HILL
COUNTRY THIS MORNING. OF GREATEST CONCERN THIS MORNING IS THE
POTENTIAL FOR SOME WINTRY PRECIPITATION TO MIX IN WITH THE RAIN AS
THE LOW BRINGS COOLER TEMPERATURES ALOFT INTO THE REGION. A 09Z
SOUNDING FROM COLLEGE STATION SHOWS A WARM NOSE AT 800MB WITH A
WARM LAYER OF APPROXIMATELY 3KFT. BELOW THIS LAYER TEMPERATURES
FALL BACK BELOW FREEZING FOR 3KFT BEFORE RISING ABOVE FREEZING
AGAIN IN THE LAST 800 FEET. THIS SUPPORTS THE CURRENT FORECAST
REASONING WHICH IS FOR RAIN WITH SOME SLIGHT CHANCE FOR SLEET
MIXED IN ALONG AND NORTH OF A LINE FROM CALDWELL TO LIVINGSTON.
WITH SURFACE TEMPERATURES IN THE UPPER 30S NO ACCUMULATION IS
EXPECTED ACROSS THIS AREA. FURTHER SOUTH...PRECIPITATION WILL
REMAIN AS RAIN. AS THE MAIN UPPER LOW APPROACHES WE COULD BRIEFLY
SEE THE POTENTIAL FOR A FEW SNOW FLURRIES TO MIX IN WITH THE RAIN
AS TEMPERATURES ALOFT BEGIN TO COOL...BUT THIS IS NOT LIKELY TO
OCCUR BEFORE THE MOISTURE SHIFTS OFF TO OUR EAST AND PRECIPITATION
ENDS ACROSS THE REGION.
THE UPPER LOW WILL CROSS THE REGION TODAY BRINGING DRIER AND
COOLER AIR IN ITS WAKE. UNSEASONABLY COLD TEMPERATURES ARE
EXPECTED WEDNESDAY AND THURSDAY MORNINGS WITH A LIGHT FREEZE
EXPECTED ACROSS THE NORTHERN HALF OF THE REGION. A SLOW WARMING
TREND WILL BEGIN LATE IN THE WEEK THROUGH THE WEEKEND AS HIGH
PRESSURE EXITS THE REGION AND ONSHORE FLOW RESUMES. NEXT CHANCE
FOR RAIN WILL BE LATE THIS WEEKEND AS A WEAK DISTURBANCE MOVES
ACROSS THE REGION. 38
MARINE...
STRONG NORTH TO NORTHWEST WINDS AND ROUGH SEAS WILL CONTINUE THROUGH
TONIGHT AS AN INTENSE UPPER LEVEL LOW PRESSURE SYSTEM MOVES THROUGH
THE UPPER TEXAS COASTAL WATERS. SMALL CRAFT ADVISORIES REMAIN IN
EFFECT...AND WIND GUSTS TO GALE FORCE WILL BE POSSIBLE. CONDITIONS
WILL BEGIN TO IMPROVE ON WEDNESDAY AS SURFACE HIGH PRESSURE BUILDS
INTO THE AREA...WINDS TURN TO THE NORTHEAST...AND SEAS COME DOWN.
LIGHT TO MODERATE NORTHEAST TO EAST WINDS ARE ANTICIPATED BEGINNING
ON THURSDAY AND CONTINUING INTO EARLY SATURDAY. A STRENGTHENING
ONSHORE FLOW IS IN THE FORECAST FOR THE END OF THE WEEKEND. 42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 43 30 48 29 54 / 20 10 0 0 0
HOUSTON (IAH) 43 32 51 30 57 / 50 10 0 0 0
GALVESTON (GLS) 46 42 50 42 57 / 50 10 0 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: BRAZORIA...CHAMBERS...GALVESTON...JACKSON...
MATAGORDA.
GM...SMALL CRAFT ADVISORY UNTIL 6 AM CST WEDNESDAY FOR THE FOLLOWING
ZONES: GALVESTON BAY...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...WATERS
FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...43
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1144 PM CST MON NOV 25 2013
.AVIATION...
THE BACK EDGE OF THE LOW CLOUD DECK WAS EDGING SOUTHWARD AT 20 MPH
AND SHOULD PASS BOTH KLBB AND KCDS NEAR 08Z TONIGHT. UNTIL
THEN...KLBB WILL HAVE THE BIGGEST CHANCE OF IFR AND MAYBE EVEN
LIFR CONDITIONS WHILE KCDS APPEARS TO HAVE SLOWLY INCREASING MVFR
CEILINGS ALREADY. KLBB ALSO WILL STILL EXPERIENCE LIGHT FREEZING
DRIZZLE AND PROBABLY AT MOST A LIGHT FOG UNTIL ABOUT 08Z. THERE
STILL WILL BE A NON-ZERO RISK FOR SURFACE OBSCURATION FROM FOG
LATER TONIGHT AT KCDS MAINLY BUT TRENDS DO NOT APPEAR TO SUPPORT
THIS TO ANY AMOUNT LARGE ENOUGH FOR TAF INCLUSION. OTHERWISE...
TREND TOWARDS VFR ON TUESDAY ARE CLEAR. RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 701 PM CST MON NOV 25 2013/
UPDATE...
ISSUED A WINTER WEATHER ADVISORY THROUGH THE EVENING AS AN AREA OF
LIGHT FREEZING DRIZZLE AND FOG WAS SPREADING SOUTHWARD THROUGH
MOST OF THE AREA. ALSO EXPECT FLURRIES. MOST SOLUTIONS DIMINISH
THE SHALLOW LIFT AND THIN THE NEAR-SURFACE MOIST LAYER AROUND
MIDNIGHT. RMCQUEEN
PREV DISCUSSION... /ISSUED 547 PM CST MON NOV 25 2013/
AVIATION...
A LOW STRATUS LAYER BEHIND THIS AFTERNOONS COLD FRONT WAS EDGING
SOUTHWARD TOWARDS KLBB EARLY THIS EVENING AND SHOULD MAKE IT INTO
KLBB VERY SHORTLY AFTER 00Z. LATEST RAP SOUNDINGS STEADILY LOWER
CEILING AT KLBB TO LIFR LEVELS EARLY THIS EVENING...THOUGH THE
HRRR RUN REVEALS LESS CERTAINTY. WE HAVE CONTINUED PREVIOUS IDEA
OF AN LIFR LAYER THIS EVENING INTO KLBB...AND EVEN ADDED TEMP
LIGHT FOG AND FREEZING DRIZZLE BASED ON UPSTREAM REPORTS. THERE IS
ALSO A LOW RISK OF A HARD DROP IN VISIBILITY AS THIS IS EMANATING
OFF THE HEAVY SNOW FIELD...THOUGH NOT EXPLICIT FOR KLBB IN ANY
GUIDANCE AT THE MOMENT. FOR KCDS...THE CURRENT IFR/LIFR CIG SHOULD
HOLD FOR SEVERAL HOURS BEFORE BREAKING...AT LEAST BASED ON SHORT
RANGE MODEL TRENDS. UNCERTAIN FOR KCDS IS IF FOG COULD REDEVELOP
LATER TONIGHT PER RAP SURFACE HUMIDITY PROGS. WILL STUDY FURTHER
FOR 06Z CYCLE. CONDITIONS EXPECTED TO BE ALL VFR TUESDAY. RMCQUEEN
PREV DISCUSSION... /ISSUED 300 PM CST MON NOV 25 2013/
SHORT TERM...
UPPER LEVEL LOW WHICH HELPED FEED MOISTURE IN FOR THE WEEKEND WINTER
WEATHER STORM WAS OVER THE PANHANDLE AT MID DAY. THE LOW CENTER
WILL MAKE AN INTERESTING TRAJECTORY DIGGING SOUTHWARD THIS EVENING
AND MAKING IT INTO THE TX HILL COUNTRY BY TUESDAY MORNING BEFORE
EJECTING NORTHEASTWARD AS IT PHASES WITH A MAIN STREAM DIVING
THROUGH MANITOBA THIS AFTERNOON. THIS WILL RESULT IN NORTHERLY FLOW
AND MUCH DRIER CONDITIONS SETTING IN. LOWS TONIGHT WILL BE TRICKY
AS SKIES ARE EXPECTED TO CLEAR NW TO SE AROUND SUNRISE TUESDAY
MORNING. GIVEN THE PROXIMITY OF THE UPPER LOW...WE MAY SEE A FEW
FLURRIES OVERNIGHT WINDS SHOULD REMAIN UP AROUND 10 KTS AND THOUGH
WIDESPREAD SNOWFALL REMAINS ON THE GROUND...COMBINATION OF SPEEDS
AND DOWNSLOPE TRAJECTORY SHOULD KEEP FOG THREAT TO A MINIMUM THOUGH
GIVEN THE SNOW-PACK...WILL GO AHEAD AND MENTION PATCHY FOG NORTHWEST.
SUNNY AND MUCH WARMER TUESDAY.
LONG TERM...
HIGH AMPLITUDE RIDGE IN PLACE ACROSS THE ROCKIES TO BEGIN THE
EXTENDED PERIOD TUESDAY NIGHT AND WEDNESDAY. SHOULD BE RATHER COLD
AGAIN OVER DEEPER SNOW-PACK SRN PANHANDLE WITH TEMPS AGAIN IN THE
TEENS. IF WINDS ARE LIGHT ENOUGH...COULD SEE SOME SINGLE DIGITS.
40S AREAWIDE FOR HIGHS WEDNESDAY...AND THEN 50S ON THURSDAY AS
FLAT UPPER RIDGE AXIS MOVES EAST OVER THE CENTRAL AND SOUTHERN PLAINS.
MAY BE PUSHING 55-60 DEGREES SOUTH BY FRIDAY AS SURFACE LEE TROUGH
DEEPENS FROM ERN CO INTO NERN NM AND WEST TEXAS. NEXT SYSTEM OF
INTEREST IS POS TILTED OPEN WAVE THAT WILL APPROACH THE AREA OVER
THE WEEKEND. SHOULD BEGIN TO SEE SOME MOISTURE RETURN LATE FRIDAY
AND SATURDAY AS SOUTHERLY WINDS INCREASE...LIKELY SOME LOW CLOUDS
CENTRAL AND EAST SECTIONS. GFS FOR NOW KEEPS SHOWERS EAST OF THE
AREA. MAY SEE FRONT INTO AREA ON SUNDAY. PROGRESSIVE NATURE OF
SYSTEM LIKELY MEANS A DRY FRONT...AND ONLY SLIGHT COOL-DOWN.
BOTH GFS AND PREV ECMWF ADVERTISING BIG PATTERN CHANGE WEDNESDAY OF
NEXT WEEK (DEC. 4) WITH CRASHING HEIGHTS OVER THE WESTERN CONUS. IF
SOME SEMBLANCE OF THIS PATTERN IS REALIZED...COULD TURN MUCH COLDER
AROUND THIS TIME...WITH WINTER WEATHER POSSIBLY MAKING A RETURN.
DOES BEAR WATCHING.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 14 36 17 39 23 / 10 0 0 0 0
TULIA 19 38 18 39 23 / 10 0 0 0 0
PLAINVIEW 22 41 20 44 25 / 10 0 0 0 0
LEVELLAND 21 45 20 44 25 / 10 0 0 0 0
LUBBOCK 23 45 22 48 27 / 10 0 0 0 0
DENVER CITY 23 46 23 48 25 / 10 0 0 0 0
BROWNFIELD 23 46 22 48 25 / 10 0 0 0 0
CHILDRESS 23 47 24 45 26 / 10 0 0 0 0
SPUR 26 48 22 48 27 / 10 0 0 0 0
ASPERMONT 25 49 26 48 29 / 10 10 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE
FOLLOWING ZONES: TXZ021>037-039>042.
&&
$$
99/99/05
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1135 PM EST MON NOV 25 2013
.SYNOPSIS...
STORM SYSTEM WILL MOVE FROM THE GULF COAST TONIGHT INTO EASTERN
NC/VA BY WEDNESDAY MORNING...AND FINALLY NORTH INTO QUEBEC BY WED
NIGHT. THIS SYSTEM WILL BRING A POTPOURRI OF WEATHER THROUGH WED
NIGHT. HIGH PRESSURE ENTERS FROM THE SOUTHWEST BY THURSDAY...AND
STICKS AROUND INTO SATURDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 1045 PM EST MONDAY...
QUICK UPDATE TO START THE ADVISORY RIGHT NOW OVER THE WEST SINCE
GETTING REPORTS OF SNOW ACCUMULATING ON ROADS ACROSS THE FAR SW.
LEAVING THE REMAINDER FROM ALONG THE BLUE RIDGE EAST STARTING AT 2
AM.
AS OF 825 PM EST MONDAY...
MID/LOW LEVEL DRY AIR PER EVENING SOUNDINGS AND LATEST OBS HAS
CONTINUED TO KEEP PRECIP FARTHER TO THE WEST THIS EVENING WITH
MOST PRECIP ON RADAR ALOFT AND JUST GOING TO SLOWLY MOISTEN THE
COLUMN ATTM. IN ADDITION THE LOW LEVEL FLOW REMAINS RATHER WEAK
AND SW JUST ABOVE THE SURFACE MAKING FOR LIMITED ISENTROPIC LIFT
AS THE BEST JET SUPPORT INCLUDING AXIS OF HIGHER DEWPOINTS LINGERS
ACROSS THE TN VALLEY. BOTH THE LATEST RAP AND HRRR HAVE DELAYED
THE ONSET OF SIGNIFICANT PRECIP UNTIL AFTER MIDNIGHT FOR THE MOST
PART WEST AND UNTIL THE EARLY MORNING HOURS OUT EAST. SINCE THIS
LOOKS IN LINE WITH THE LATEST TRENDS...HAVE DELAYED ONSET OF POPS
ACROSS THE REGION FOR COUPLE HOURS BEFORE THINGS REALLY MOISTEN
AND PRECIP QUICKLY INCREASES ESPCLY BLUE RIDGE AND ACROSS THE
SOUTH AFTER MIDNIGHT. EVENING RAOBS AND SURFACE OBS INDICATE STILL
LOTS OF ROOM FOR WET BULB COOLING ALTHOUGH TREND OUT WEST HAS BEEN
FOR DEWPOINTS TO RISE WITHOUT MUCH COOLING AS PRECIP EVAPORATES
BEFORE REACHING THE SURFACE. THIS SUPPORTS KEEPING A MIXED BAG BUT
A LITTLE MORE SNOW WEST AT THE ONSET WITH SOME CHANCE OF
SNOW/SLEET EAST THEN MOSTLY FZRA/SLEET. ADJUSTED TEMPS DOWN SOME
FOR CURRENT READINGS WITH MOST LIKELY NOT DROPPING TOO MUCH MORE
UNTIL HEAVIER PRECIP ARRIVES.
MAIN ADJUST TO HEADLINES WAS TO EXTEND THE GOING ADVISORY LONGER
INTO THE AFTERNOON ON TUESDAY FOR AMHERST/BOTETOURT COUNTIES
GIVEN FORECAST SOUNDINGS SHOWING TEMPS UNABLE TO GET MUCH ABOVE
FREEZING UNTIL LATE IN THE DAY. THIS MAY ALSO BE THE CASE ON THE
NORTH SIDE OF HIGHWAY 460 IN ROANOKE AND MONTGOMERY COUNTIES BUT
HELD THOSE AREAS AT A NOON EXPIRATION FOR NOW GIVEN POTENTIAL FOR
THAT AREA TO SEE WARMING FROM HEAVIER RAINFALL THROUGH THE WARM
LAYER SOONER.
PREVIOUS DISCUSSION AS OF 250 PM EST MONDAY...
DURING THIS TIME PERIOD WILL BE DEALING WITH NUISANCE WINTER WX
WHERE PRECIP ARRIVES INTO THE NC MTNS/FAR SW VA BEFORE MIDNIGHT
OVERSPREADING THE REGION BY DAWN. SUNSHINE CAME OUT TODAY OVER MOST
OF THE AREA ALLOWING TEMPS TO CLIMB ABOVE FREEZING AND AROUND 40 IN
SOUTHSIDE VA/FAR SW VA. DEWPOINTS HOWEVER ARE TANKED IN THE SINGLE
DIGITS. HENCE LIES THE PROBLEM TONIGHT. UPSTREAM CLOUDS ALREADY
POURING BACK IN AND THIS MAY HELP IN TERMS OF NOT ALLOWING TEMPS TO
DROP TOO FAR AFTER SUNSET AS CLOUDS ACT AS A BLANKET. THEN...AS THE
PRECIP ARRIVES...GIVEN THE DRY AIR IT MAY TAKE AN HOUR OR TWO TO
SATURATE THE LOW LVLS BUT ONCE IT DOES...THE TEMP/DEWPOINT PROFILE
WILL HEAD TOWARD CRITICAL LEVELS FOR WINTER PRECIP. AT THE ONSET THE
TEMPS SHOULD BE COLD ENOUGH FOR SLEET OR SNOW THEN CHANGE QUICKLY TO
FREEZING RAIN AS STRONG SOUTH TO SOUTHWEST FLOW BRINGS A WARM NOSE
INTO THE MTNS AFTER MIDNIGHT AND REACHING OUR NRN CWA BY MID
MORNING. WITH INSITU WEDGE AND SFC WET BULBING TO AT OR BELOW ZERO
WITH WARM NOSE...FREEZING RAIN WILL BECOME AN ISSUE. GROUND HAS
TURNED COLDER AS EVIDENCE BY SOIL TEMPS IN THE LOWER TO MID 30S.
THERE WILL BE A LIGHT ACCUMULATION OF SLEET OR SNOW AT THE
ONSET...LESS THAN AN INCH...THEN QUICKLY CHANGING TO FZRA WITH
GLAZING EXPECTED ALONG TREE/POWERLINES AND METAL OBJECTS FIRST THEN
BRIDGES/OVERPASSES. BASED ON RAINFALL RATE AND WARM AIR ALOFT THE
ACCRETION OF ICE WILL BE IN A 2-4 HOUR WINDOW AS THE BETTER LIFT
TAKES PLACE AFTER 12Z...ALLOWING THE RATES TO INCREASE AND DRAG DOWN
WARMER AIR. MODERATE TO HEAVIER RAINFALL USUALLY DOES NOT STICK TO
ROADS VERY WELL WHEN SFC TEMPS ARE EXPECTED TO BE NEAR FREEZING.
NEED MORE LIKE MID TO UPPER 20S OR LOWER.
STILL THERE SEEMS TO BE ENOUGH EVIDENCE THAT MOST OF OUR CWA WILL
GET AT LEAST A TRACE OF ICE WITH HIGHER AMOUNTS ALONG THE BLUE RIDGE
FROM BOONE/BLOWING ROCK NORTH TO BUENA VISTA/AMHERST. ALSO THE
ALLEGHANY HIGHLAND SHOULD SEE UP TO 2/10S. IT ONLY TAKES A TRACE OF
ICE TO CAUSE TRAVEL PROBLEMS. BASED ON THIS AND COLLABORATION WITH
SURROUNDING NWS OFFICES...WE HAVE A WINTER WX ADVISORY OUT FOR THE
ENTIRE CWA FOR TONIGHT-MIDDAY/AFTERNOON TUESDAY...ENDING EARLIER
IN THE SOUTH.
TEMPS THIS EVENING WILL START FALLING SLOWLY THEN DROP A LITTLE MORE
ONCE PRECIP ARRIVES ALOFT LEADING TO EVAP COOLING. LOOKING AT LOWS
FROM THE UPPER 20S TO AROUND 30...THEN WARMING GRADUALLY TO ABOVE
FREEZING DURING THE DAY TUESDAY...FIRST IN THE FAR SW VA/SRN WV AREA
OUTSIDE THE WEDGE AND INTO WRN NC MTNS ALONG THE TN BORDER...THEN
SOUTHSIDE VA/NW NC PIEDMONT EXPANDING NORTHWARD BY AFTERNOON TO THE
NRN BLUE RIDGE. COULD BE A DEAL WHERE SOME VALLEYS ACROSS
BATH/ROCKBRIDGE/AMHERST TAKE INTO TUE EVENING...BUT THINK THE WARMER
RAIN AND HIGHER RATES TO BRING IT UP. FOR MOST OF US...THE ICE WILL
BE MELTED AND GONE BY MIDDAY/EARLY AFTERNOON WITH HIGHS EXPECTED TO
BE IN THE MID TO UPPER 30S SOUTH...TO LOWER 30S NORTH. BUT WILL BE
DEALING WITH MODERATE TO HEAVY AT TIMES COLD NOVEMBER RAINS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 340 PM EST MONDAY...
GFS AND ECMWF ARE IN GOOD AGREEMENT WITH THE NORTHERN AND SOUTHERN
BEGINNING TO PHASE TUESDAY NIGHT AND BECOME ONE SYSTEM WEDNESDAY.
THE UPPER LEVEL LOW TRACKING ALONG THE GULF COAST WILL OPEN OVER THE
TENNESSEE VALLEY AND MERGE WITH THE NORTHERN STREAM TROUGH ENTERING
THE OHIO VALLEY BY WEDNESDAY MORNING. THE SURFACE LOW PRESSURE OVER
GEORGIA ON TUESDAY EVENING WILL TRACK NORTHEAST ALONG THE LEE SIDE
OF THE APPALACHIAN MOUNTAINS EARLY WEDNESDAY MORNING. AS THE
NORTHERN STREAM TROUGH BECOMES DOMINATE...A SECONDARY SURFACE LOW IS
EXPECTED TO DEVELOP OVER THE VIRGINIA PIEDMONT TUESDAY NIGHT...THEN
LIFT TO NEW ENGLAND ON WEDNESDAY. BY WEDNESDAY EVENING...THE SFC LOW
WILL BE LOCATED OVER MAINE WITH TRAILING COLD FRONT PUSHING INTO THE
ATLANTIC OCEAN. HIGH PRESSURE WILL BE BUILDING ACROSS OUR REGION
WEDNESDAY NIGHT INTO THURSDAY.
THE RAIN MAY BE HEAVY AT TIMES TUESDAY AFTERNOON INTO WEDNESDAY
MORNING. JET DYNAMICS AND LIFT ASSOCIATED WITH PASSING SURFACE AND
SHORTWAVES WILL BRING HIGH RAINFALL RATES TO THE AREA. COLDER AIR
WILL PUSH INTO OUR REGION TUESDAY NIGHT INTO WEDNESDAY MORNING. RAIN
WILL TRANSITION TO SNOW STARTING ALONG THE HIGHER ELEVATION THEN
ACROSS THE REST ON WEDNESDAY. MOISTURE WILL PULL OUT OF MOST OF THE
AREA WEDNESDAY EVENING INTO WEDNESDAY NIGHT. NORTHWEST UPSLOPE SNOW
SHOWERS AND SNOW FLURRIES WILL CONTINUE INTO WEDNESDAY NIGHT INTO
THURSDAY. POTENTIAL STORM TOTAL SNOW FOR THE MOUNTAINS WILL LIKELY
RANGE FROM 1-4 INCHES TUESDAY NIGHT INTO WEDNESDAY...WITH UPWARDS OF
4 TO 6 INCHES ON WESTERN SLOPES TUESDAY NIGHT INTO WEDNESDAY NIGHT.
LIGHTER AMOUNTS OF SNOW EXPECTED GENERALLY LESS THAN INCH IN THE
EAST. INCREASING WINDS WILL ACCOMPANY THE UPSLOPE SNOW SHOWERS.
STRONG PRESSURE RISES AND COLD AIR ADVECTION ALONG WITH A 45-55KT
CROSS BARRIER JET WILL BRING SUSTAIN WINDS OF 20-30 MPH GUSTING TO
AROUND 50 MPH FOR COUNTIES ALONG THE BLUE RIDGE...PARTICULARLY THE
NORTH CAROLINA HIGH COUNTY AND GRAYSON HIGHLANDS. WIND SPEED WILL BE
CLOSE TO ADVISORY LEVELS. WILL HOLD OFF ON ISSUING HEADLINES FOR
SNOW AND WINDS FOR NOW TO AVOID CONFUSION WITH ONGOING EVENT. ONE
SET OF HEADLINES WILL BE REPLACED BY ANOTHER SET EVERY 6-12 HOURS.
PLAN TO HIGHLIGHT THE POTENTIAL IN HWO. AS THIS SYSTEM DEVELOPS AND
MATURES OVER THE REGION...EVERYONE SHOULD BE PREPARED FOR RAPIDLY
CHANGING CONDITIONS...ESPECIALLY IF YOU ARE TRAVELING ALONG THE EAST
COAST THIS WEEK.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 1245 PM EDT MONDAY...
LARGE SCALE PATTERN TRANSITIONS TO ZONAL FLOW WITH SURFACE HIGH
PRESSURE IN CONTROL THROUGH THE WEEKEND. THIS RESULTS IN SLOWLY
MODERATING TEMPERATURES...YET SHOULD REMAIN BELOW SEASONABLE
AVERAGES EVEN BY SUNDAY. ALSO THINKING HIGHER CLOUDS WILL BECOME
MORE PREVALENT BY SUNDAY WHICH WOULD KEEP HIGHS DOWN SOMEWHAT. LONG
TERM MODELS GENERALLY IN AGREEMENT THAT NEXT WEATHER SYSTEM WILL
MATERIALIZE IN THE SOUTHERN PLAINS LATE SUNDAY AND THEN QUICKLY
APPROACHING THE SOUTHERN APPALACHIANS FROM THE SOUTHWEST ON MONDAY.
RIGHT NOW THE 00Z ECWMF IS A LITTLE FASTER THAN THE 12Z GFS AND
GIVEN THE GENERALLY ZONAL FLOW PATTERN THIS FASTER IDEA IS
FAVORED...ESPECIALLY AS A STRONGER SYSTEM DIGS INTO THE WESTERN U.S.
AND EJECTS THIS WAVE OUT ACROSS THE PLAINS AND TOWARDS THE
APPALACHIANS. THE HIGH PRESSURE WILL BE WEAKENING AND RETREATING AS
THIS SYSTEM APPROACHES BY EARLY MONDAY BUT AIRMASS APPEARS THAT IT
WILL MODERATE ENOUGH SO THAT PRECIP TYPE REMAINS JUST RAIN. HOWEVER
IT WILL BE WORTH KEEPING AN EYE ON THE TIMING OF PRECIP ARRIVAL AND
STRENGTH OF LINGERING HIGH...AS WELL AS HOW LOW INITIAL WET BULB
TEMPERATURES ARE WHEN PRECIP ARRIVES. CANT RULE OUT SOME POCKETS OF
FREEZING RAIN IF THIS COMES IN OVERNIGHT...BUT AT THIS POINT STILL A
LONG WAY OFF.
&&
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
AS OF 1130 PM EST MONDAY...
BAND OF MIXED SNOW AND SLEET CONTINUES TO PUSH EAST TOWARD THE
BLUE RIDGE AND SHOULD BRING SOME -SN TO KBCB/ROA OVER THE NEXT HOUR
OR TWO BEFORE COVERAGE BRIEFLY FADES. THIS WILL RESULT IN LOWERING
CIGS TO MVFR OVER THE WEST BEFORE MORE SIGNIFICANT MIXED PRECIP
ARRIVES WELL AFTER MIDNIGHT. THUS LOOKING AT DETERIORATING FLYING
WEATHER AS THE NIGHT WEARS ON WITH WIDESPREAD LOW CIGS AND AT
LEAST MVFR VSBYS OVER THE WEST BY DAYBREAK TUESDAY WHEN PRECIP
SHOULD TAKE THE FORM OF FREEZING RAIN. FARTHER EAST EXPECTING LYH
TO START AS FZRA WITH PERHAPS A BIT OF SN/PL WITH THE INITIAL
BATCH. DAN WILL BE BORDERLINE ON FZRA BUT TEMPS SHOULD BE HUGGING
32-33F AT THE SFC SO INCLUDED A HOUR OR TWO OF -FZRA THERE EARLY
TUESDAY. WARM NOSE ALOFT TO CHANGE FZRA TO RAIN AT ALL SITES
AROUND MIDDAY TUESDAY ALTHOUGH SPOTS LIKE KLWB/KLYH MAY KEEP -FZRA
INTO MID OR LATE AFTERNOON. RAIN BECOMES HEAVY AT TIMES TUESDAY
AFTERNOON ESPECIALLY AT BCB/ROA/LYH/DAN. WILL EXPECT TO SEE
FLUCTUATIONS IN CIGS/VSBYS BASED ON RAINFALL RATES BUT OVERALL
SHOULD BE IFR TO LIFR WITH MOUNTAIN OBSCURATIONS LIKELY. WITH THE
STRONG SE FLOW ABOVE THE SURFACE WILL ALSO BE SEEING LLWS
POTENTIAL AT ALL LOCATIONS THROUGH THE DAY TUESDAY AS LATEST
SOUNDINGS INDICATE 35-45 KTS JUST ABOVE THE SURFACE ESPCLY IN THE
AFTERNOON. THEREFORE INCLUDED LLWS AT MOST SPOTS FOR STRONG SOUTH
TO SE FLOW DEVELOPING RIGHT AFTER SUNRISE ON TUESDAY.
MODERATE TO HEAVY RAINFALL CONTINUES TUESDAY NIGHT WITH LOCATIONS
ACROSS SE WVA TRANSITIONING BACK TO SNOW BY EARLY WEDNESDAY. THIS
WILL KEEP LOW IFR/LIFR CIGS AND MVFR TO IFR VSBYS GOING TUESDAY
NIGHT AS THE CORE OF THE LOW PRESSURE SYSTEM TRACKS ACROSS THE
AREA.
RAIN CHANGES TO A SIGNIFICANT UPSLOPE EVENT BY WED WITH PERHAPS A
TRAILING DEFORMATION BAND OF SNOW WORKING EAST TOWARD THE BLUE
RIDGE WED MORNING. THIS MAY RESULT IN A FEW INCHES OF SNOW
ACCUMULATION AROUND KBLF/KLWB AND POSSIBLY A LIGHT AMOUNT EAST TO
KBCB. WIND WILL ALSO BECOME AN ISSUE ACROSS THE MOUNTAINS WITH NW
WIND GUSTS TO 45 KTS OR MORE WED WITH A SIGNIFICANT COASTAL LOW
MOVING ACROSS COASTAL NEW ENGLAND.
RAPID IMPROVEMENT WILL OCCUR ON THURSDAY AS THE STORM SYSTEM
PULLS AWAY AND DRIER AIR WORKS IN...RESULTING IN WIDESPREAD VFR
CONDITIONS. VFR THEN CONTINUES UNDER HIGH PRESSURE FOR FRIDAY
THROUGH SATURDAY.
&&
.HYDROLOGY...
AS OF NOON EST MONDAY...
MODEL CONSENSUS AND HPC GUIDANCE GENERALLY IN THE 2 TO 3 INCH RANGE
OF LIQUID QPF FOR THE IMPENDING STORM EVENT ALTHOUGH SOME SREF
ENSEMBLE MEMBERS SHOWING OVER 4 INCHES BY ABOUT 12Z WEDNESDAY THE
27TH. QUESTION IS WHAT IMPACT THE RUNOFF FROM THIS WILL HAVE ON AREA
STREAMS AND RIVERS. POINT ONE IS THAT RIVERS ARE STARTING OFF AT
VERY LOW LEVELS ESPECIALLY ACROSS THE LOWER PORTIONS OF OUR RIVER
BASINS...ACROSS THE PIEDMONT. USGS DAILY STREAMFLOW PERCENTILES AS
OF THIS MORNING ARE SHOWING NEARLY ALL PIEDMONT RIVER AND STREAM
LOCATIONS RUNNING AT FLOWS BELOW THE 25TH PERCENTILE FOR THE DATE
AND SOME BELOW THE 10TH PERCENTILE. THIS ALSO HOLDS TRUE FOR MUCH OF
THE UPPER JAMES RIVER BASIN. 60-DAY RAINFALL DEFICITS HAVE BECOME
QUITE SIGNIFICANT...REACHING 4 TO 6 INCHES IN MANY OF THESE BASINS
OR AROUND 25 PERCENT OF NORMAL. DETERMINISTIC RIVER FORECASTS ISSUED
THIS MORNING BY THE FOUR RFCS SERVING THE BLACKSBURG HYDRO SERVICE
AREA INCLUDE 48 HOURS OF QPF THROUGH 12Z WEDNESDAY OF GENERALLY 2 TO
2.5 INCHES. AT OF THIS PACKAGE NO RIVERS ARE FORECAST TO REACH FLOOD
STAGE OR EVEN ACTION STAGE (GENERALLY A FEW FEET BELOW FLOOD STAGE)
ALTHOUGH SEVERAL COME CLOSE...INCLUDING THE NORTH FORK HOLSTON RIVER
AT SALTVILLE AND GREENBRIER RIVER AT ALDERSON. THAT SAID HYDROLOGIC
MODELS TEND TO HAVE SOME DIFFICULTY AFTER EXTENDED DRY PERIODS IN
HANDLING RUNOFF WHICH IS GENERALLY MUCH MORE EFFICIENT IN THE COOL
SEASON. HENCE...THE RESPONSE ON RIVERS REMAINS SOMEWHAT UNCERTAIN
BUT NOT ENOUGH CONFIDENCE TO ISSUE A FLOOD WATCH. NOT EXPECTING MUCH
IF ANY CONVECTION WITH THIS STORM SO RAINFALL RATES SHOULD REMAIN
MODEST..IN THE 0.10 TO 0.25 INCH PER HOUR RANGE. BUT HIGHER RAINFALL
RATES IN ANY ELEVATED STORMS THAT ARE ABLE TO DEVELOP COULD LEAD TO
LOCALIZED RUNOFF PROBLEMS. THESE COULD BE HANDLED WITH SHORT-FUSE
HYDROLOGIC PRODUCTS..FLOOD ADVISORIES OR EVEN FLASH FLOOD WARNINGS
BUT THE LIKELIHOOD AT THIS POINT IS QUITE LOW FOR THIS TO OCCUR.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER WEATHER ADVISORY UNTIL 4 PM EST TUESDAY FOR VAZ018>020-
023-024-035.
WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR VAZ007-
009>017.
WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR VAZ022-
032>034-043>047-058-059.
NC...WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR NCZ001-002-
018.
WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR NCZ003>006-
019-020.
WV...WINTER WEATHER ADVISORY UNTIL 4 PM EST TUESDAY FOR WVZ045.
WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR WVZ042>044.
&&
$$
SYNOPSIS...RAB/WP
NEAR TERM...JH/WP
SHORT TERM...KK
LONG TERM...SK
AVIATION...JH/RAB/WP
HYDROLOGY...PC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
712 PM CST WED NOV 27 2013
.UPDATE...
ISSUED AT 712 PM CST WED NOV 27 2013
FRONTOGENETIC BAND FROM NORTHERN MINNESOTA INTO NORTH CENTRAL
WISCONSIN CONTINUES TO PRODUCE EFFICIENT SNOW AMOUNTS WITH DECENT
LIFT IN DENDRITIC SNOW GROWTH ZONE. REPORTS OF 2 TO 4 INCHES
UPSTREAM...AND EVEN THOUGH FORCING IS FORECAST TO WEAKEN AS SYSTEM
ADVECTS EAST...BUMPED UP SNOW ACCUMULATIONS SLIGHTLY MAINLY ALONG
AND NORTH OF HIGHWAY 29 IN PARTS OF NORTH CENTRAL WISCONSIN TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH THANKSGIVING)
ISSUED AT 310 PM CST WED NOV 27 2013
OVERALL A QUIET WEATHER PERIOD THROUGH THE WEEKEND...AFTER SOME
LIGHT SNOW ACROSS THE NORTH TONIGHT.
HAVE BEEN MONITORING SHORTWAVE TROUGH 1 MOVING INTO MINNESOTA
THIS AFTERNOON WITH LIGHT SNOW IN THE 1-2SM VISIBILITY
RANGE...WITH A BIT LOWER FURTHER NORTHWEST ALONG THE MN/CANADA
BORDER. ECHO IS INCREASING IN NW WI...BUT THE PRECIPITATION IS
WORKING ON SATURATION AND NOT MAKING IT TO THE SURFACE. THE UPPER
TROPOSPHERIC SHORTWAVE TROUGH IS LOCATED IN NWRN MN AT 20Z PER
GOES WATER VAPOR IMAGERY...WITH SHORTWAVE TROUGH 2 ON ITS HEALS
JUST NORTHWEST OF LAKE WINNIPEG. MORNING RAOB AT KMPX WAS DEEPLY
DRY BUT THE FORCING WITH THE SHORTWAVE TROUGH IS WORKING PRETTY
RAPIDLY TO SATURATE THE COLUMN AND PRODUCE SNOW....ON THE ORDER OF
A COUPLE HOURS. PER THE LATEST RAP...THIS FORCING IS A
CONTRIBUTION FROM WARM ADVECTION IN THE LOW LEVELS / AND 700MB
FRONTOGENESIS/ AND MID-UPPER LEVEL QG CONVERGENCE.
THE FIRST SHORTWAVE WILL TRACK TOWARD THE NORTHERN FORECAST AREA THIS
AFTERNOON AND ARRIVE AROUND 6-7 PM IN CLARK AND TAYLOR COUNTIES
PER RAP FORECASTS AND TRACKING. THIS FIRST SHORTWAVE TROUGH
WEAKENS AS IT MOVES IN PER THE CONSENSUS MODEL GUIDANCE AS THE
SECOND WAVE INTENSIFIES AND DEEPENS. HOWEVER...THERE IS GUIDANCE
/HRRR/ SOLUTIONS DIMINISHING THE WEATHER AS IT MOVES SOUTHEAST
AND DRY AIR IN PLACE WILL DOMINATE. WITH CONSENSUS FORCING SWIPING
A BAND OF SNOW IN THE EVENING AND CURRENT CONDITIONS...HAVE
FORECAST THE SNOW TO MOVE IN DURING THE EVENING AND ACCUMULATE...MAINLY
I-94 AND NORTH. THIS IS NOT A BIG CHANGE TO ONGOING FORECAST..BUT
HIGHER CONFIDENCE. WILL LIKELY HIT THIS A BIT IN THE SOCIAL MEDIA
AND SPECIAL WEATHER STATEMENTS WITH MORE TRAVEL THIS EVENING
HAPPENING.
SOME DIFFICULTY IN TRYING TO FIGURE OUT THE REMAINDER OF THE
NIGHT AFTER MIDNIGHT...AHEAD OF THE SECOND SHORT WAVE TROUGH. IT
APPEARS THE FRONTOGENESIS NEAR 700MB WILL BE STRONGER THAN THE
FIRST SHORTWAVE AND WITH THE UPPER QG FORCING MAINLY OVER NRN WI
/MODEL CONSENSUS/...SNOW SEEMS TO BE A GIVEN. BUT AS SHORTWAVE
TROUGH 2 DEEPENS...THE FORCING SHIFTS INTO NORTHERN WI AND MAY
SPREAD ITS SNOW NORTH OF TAYLOR COUNTY. FEEL FAIRLY CONFIDENT SNOW
WILL OCCUR OVERNIGHT...BUT HAVE DECIDED TO MOVE IT NORTH WITH TIME
AND LEAVE FLURRIES SOUTH TO I-94. THE SNOW RATIOS COULD BE QUITE
HIGH WITH THIS SNOW WITH MOST OF THE SATURATED COLUMN IN THE
DENDRITE GROWTH ZONE -12 TO -18C...THUS LOW QPF COULD PRODUCE AN
INCH PRETTY EASY.
MAINLY FLURRIES SHOULD REMAIN DURING THE EARLY MORNING THURSDAY WITH
ROADS CLEANING UP FOR TRAVEL. SUN IS EXPECTED BY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 PM CST WED NOV 27 2013
A PERIOD OF QUIET WEATHER WITH SOME MODERATION IN TEMPERATURES
BEGINNING FRIDAY...BUT A COLD START THAT MORNING UNDER HIGH
PRESSURE AND CLEAR SKIES. IF A BIT MORE SNOW FALLS IN TAYLOR
COUNTY TONIGHT ACROSS TAYLOR COUNTY...FRIDAY MORNING COULD BE NEAR
ZERO.
NEXT WEATHER SYSTEM SHIFTS ACROSS NORTHERN GREAT LAKES FRIDAY
NIGHT AND SATURDAY WITH THE MORE FAVORABLE FORCING NORTH OF THE
AREA. MAYBE SOME CLOUDS AND FLURRIES IN TAYLOR COUNTY BUT HAVE
KEPT DRY FORECAST INTACT.
SUNDAY THROUGH WEDNESDAY...LOW CONFIDENCE IN THIS PERIOD AS THE
MODEL GUIDANCE HAS DIFFERENT EVOLUTIONS AND TIMING TO THE MAJOR
READJUSTMENT OF THE LARGE SCALE PATTERN OVER NORTH AMERICA. MAJOR
TROUGH AND COLD POOL OF AIR INVADE THE WESTERN CONUS WITH AN
ASTOUNDING -3.5 TO -4 STANDARD DEVIATION BELOW NORMAL 850 MB TEMP
IN THE WESTERN CONUS. BECAUSE OF THE SPREAD IN THE MODELS AND HOW
ENERGY EJECTS OUT OF THE TROUGH...THE FORECAST HAS SMALL
PRECIPITATION CHANCES MONDAY TO WEDNESDAY. THIS COULD BE A DRY
PERIOD SHOULD THE 27.12Z ECMWF SOLUTION OCCUR...WHICH THE 27.12Z
GFS TRENDED TOWARD...WITH MORE WEATHER LATER IN THE WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 527 PM CST WED NOV 27 2013
AS SHORT WAVE TROUGH DROPS INTO WESTERN GREAT LAKES THIS EVENING...
FRONTOGENETIC BAND WILL SET UP ACROSS NORTHERN AND CENTRAL WISCONSIN
WITH SOME MVFR VISIBILITIES AND CEILINGS. BETTER CONDITIONS EXPECTED
SOUTH AND WEST OF THERE...STAYING VFR.
SECOND WAVE ON HEELS OF FIRST WILL SWEEP DOWN EARLY ON THANKSGIVING
MORNING BUT THREAT FOR SNOW WILL BE EVEN FURTHER NORTHEAST. MAIN
AVIATION IMPACT WILL BE TRAPPED STRATUS LAYER IN COLD AIR ADVECTION
ZONE BEHIND COLD FRONT. CEILINGS COULD BECOME MVFR FOR A TIME
THURSDAY BEFORE DRIER AIR ALOFT MIXES LOWER CEILINGS OUT LATER IN
DAY. MAY BE A BIT PESSIMISTIC BUT INTRODUCED FAR MORE SKY COVER FOR
THURSDAY UNTIL RIDGE BUILDS IN THURSDAY NIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...SHEA
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
527 PM CST WED NOV 27 2013
.SHORT TERM...(THIS EVENING THROUGH THANKSGIVING)
ISSUED AT 310 PM CST WED NOV 27 2013
OVERALL A QUIET WEATHER PERIOD THROUGH THE WEEKEND...AFTER SOME
LIGHT SNOW ACROSS THE NORTH TONIGHT.
HAVE BEEN MONITORING SHORTWAVE TROUGH 1 MOVING INTO MINNESOTA
THIS AFTERNOON WITH LIGHT SNOW IN THE 1-2SM VISIBILITY
RANGE...WITH A BIT LOWER FURTHER NORTHWEST ALONG THE MN/CANADA
BORDER. ECHO IS INCREASING IN NW WI...BUT THE PRECIPITATION IS
WORKING ON SATURATION AND NOT MAKING IT TO THE SURFACE. THE UPPER
TROPOSPHERIC SHORTWAVE TROUGH IS LOCATED IN NWRN MN AT 20Z PER
GOES WATER VAPOR IMAGERY...WITH SHORTWAVE TROUGH 2 ON ITS HEALS
JUST NORTHWEST OF LAKE WINNIPEG. MORNING RAOB AT KMPX WAS DEEPLY
DRY BUT THE FORCING WITH THE SHORTWAVE TROUGH IS WORKING PRETTY
RAPIDLY TO SATURATE THE COLUMN AND PRODUCE SNOW....ON THE ORDER OF
A COUPLE HOURS. PER THE LATEST RAP...THIS FORCING IS A
CONTRIBUTION FROM WARM ADVECTION IN THE LOW LEVELS / AND 700MB
FRONTOGENESIS/ AND MID-UPPER LEVEL QG CONVERGENCE.
THE FIRST SHORTWAVE WILL TRACK TOWARD THE NORTHERN FORECAST AREA THIS
AFTERNOON AND ARRIVE AROUND 6-7 PM IN CLARK AND TAYLOR COUNTIES
PER RAP FORECASTS AND TRACKING. THIS FIRST SHORTWAVE TROUGH
WEAKENS AS IT MOVES IN PER THE CONSENSUS MODEL GUIDANCE AS THE
SECOND WAVE INTENSIFIES AND DEEPENS. HOWEVER...THERE IS GUIDANCE
/HRRR/ SOLUTIONS DIMINISHING THE WEATHER AS IT MOVES SOUTHEAST
AND DRY AIR IN PLACE WILL DOMINATE. WITH CONSENSUS FORCING SWIPING
A BAND OF SNOW IN THE EVENING AND CURRENT CONDITIONS...HAVE
FORECAST THE SNOW TO MOVE IN DURING THE EVENING AND ACCUMULATE...MAINLY
I-94 AND NORTH. THIS IS NOT A BIG CHANGE TO ONGOING FORECAST..BUT
HIGHER CONFIDENCE. WILL LIKELY HIT THIS A BIT IN THE SOCIAL MEDIA
AND SPECIAL WEATHER STATEMENTS WITH MORE TRAVEL THIS EVENING
HAPPENING.
SOME DIFFICULTY IN TRYING TO FIGURE OUT THE REMAINDER OF THE
NIGHT AFTER MIDNIGHT...AHEAD OF THE SECOND SHORT WAVE TROUGH. IT
APPEARS THE FRONTOGENESIS NEAR 700MB WILL BE STRONGER THAN THE
FIRST SHORTWAVE AND WITH THE UPPER QG FORCING MAINLY OVER NRN WI
/MODEL CONSENSUS/...SNOW SEEMS TO BE A GIVEN. BUT AS SHORTWAVE
TROUGH 2 DEEPENS...THE FORCING SHIFTS INTO NORTHERN WI AND MAY
SPREAD ITS SNOW NORTH OF TAYLOR COUNTY. FEEL FAIRLY CONFIDENT SNOW
WILL OCCUR OVERNIGHT...BUT HAVE DECIDED TO MOVE IT NORTH WITH TIME
AND LEAVE FLURRIES SOUTH TO I-94. THE SNOW RATIOS COULD BE QUITE
HIGH WITH THIS SNOW WITH MOST OF THE SATURATED COLUMN IN THE
DENDRITE GROWTH ZONE -12 TO -18C...THUS LOW QPF COULD PRODUCE AN
INCH PRETTY EASY.
MAINLY FLURRIES SHOULD REMAIN DURING THE EARLY MORNING THURSDAY WITH
ROADS CLEANING UP FOR TRAVEL. SUN IS EXPECTED BY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 PM CST WED NOV 27 2013
A PERIOD OF QUIET WEATHER WITH SOME MODERATION IN TEMPERATURES
BEGINNING FRIDAY...BUT A COLD START THAT MORNING UNDER HIGH
PRESSURE AND CLEAR SKIES. IF A BIT MORE SNOW FALLS IN TAYLOR
COUNTY TONIGHT ACROSS TAYLOR COUNTY...FRIDAY MORNING COULD BE NEAR
ZERO.
NEXT WEATHER SYSTEM SHIFTS ACROSS NORTHERN GREAT LAKES FRIDAY
NIGHT AND SATURDAY WITH THE MORE FAVORABLE FORCING NORTH OF THE
AREA. MAYBE SOME CLOUDS AND FLURRIES IN TAYLOR COUNTY BUT HAVE
KEPT DRY FORECAST INTACT.
SUNDAY THROUGH WEDNESDAY...LOW CONFIDENCE IN THIS PERIOD AS THE
MODEL GUIDANCE HAS DIFFERENT EVOLUTIONS AND TIMING TO THE MAJOR
READJUSTMENT OF THE LARGE SCALE PATTERN OVER NORTH AMERICA. MAJOR
TROUGH AND COLD POOL OF AIR INVADE THE WESTERN CONUS WITH AN
ASTOUNDING -3.5 TO -4 STANDARD DEVIATION BELOW NORMAL 850 MB TEMP
IN THE WESTERN CONUS. BECAUSE OF THE SPREAD IN THE MODELS AND HOW
ENERGY EJECTS OUT OF THE TROUGH...THE FORECAST HAS SMALL
PRECIPITATION CHANCES MONDAY TO WEDNESDAY. THIS COULD BE A DRY
PERIOD SHOULD THE 27.12Z ECMWF SOLUTION OCCUR...WHICH THE 27.12Z
GFS TRENDED TOWARD...WITH MORE WEATHER LATER IN THE WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 527 PM CST WED NOV 27 2013
AS SHORT WAVE TROUGH DROPS INTO WESTERN GREAT LAKES THIS EVENING...
FRONTOGENETIC BAND WILL SET UP ACROSS NORTHERN AND CENTRAL WISCONSIN
WITH SOME MVFR VISIBILITIES AND CEILINGS. BETTER CONDITIONS EXPECTED
SOUTH AND WEST OF THERE...STAYING VFR.
SECOND WAVE ON HEELS OF FIRST WILL SWEEP DOWN EARLY ON THANKSGIVING
MORNING BUT THREAT FOR SNOW WILL BE EVEN FURTHER NORTHEAST. MAIN
AVIATION IMPACT WILL BE TRAPPED STRATUS LAYER IN COLD AIR ADVECTION
ZONE BEHIND COLD FRONT. CEILINGS COULD BECOME MVFR FOR A TIME
THURSDAY BEFORE DRIER AIR ALOFT MIXES LOWER CEILINGS OUT LATER IN
DAY. MAY BE A BIT PESSIMISTIC BUT INTRODUCED FAR MORE SKY COVER FOR
THURSDAY UNTIL RIDGE BUILDS IN THURSDAY NIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...SHEA
AREA FORECAST DISCUSSION
NWS ALBANY NY
331 AM EST THU NOV 28 2013
.SYNOPSIS...
LOW PRESSURE WILL CONTINUE TO DEEPEN AND INTENSIFY AS IT MOVES
FURTHER NORTHEAST INTO THE CANADIAN MARITIMES...AS HIGH PRESSURE
WILL ATTEMPT TO BUILD IN FROM THE SOUTHEAST. BLUSTERY AND COLD
CONDITIONS ARE EXPECTED FOR THANKSGIVING TODAY WITH SOME LAKE
EFFECT SNOW SHOWERS WEST OF THE GREATER CAPITAL REGION. A WEAK
DISTURBANCE WILL BRING SOME LAKE EFFECT SNOW SHOWERS AND FLURRIES
TONIGHT INTO EARLY FRIDAY MAINLY WEST OF THE HUDSON RIVER
VALLEY...BEFORE HIGH PRESSURE BUILDS IN LATE FRIDAY INTO THE FIRST
HALF OF THE WEEKEND WITH DRY WEATHER AND BELOW NORMAL TEMPERATURES
TO CLOSE NOVEMBER.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 330 AM EST...HAPPY THANKSGIVING EVERYONE ! BLUSTERY AND COLD
CONDITIONS GREET ERN NY AND WRN NEW ENGLAND THIS MORNING...AS THE
UPPER TROUGH AXIS TO THE STRONG STORM SYSTEM YESTERDAY HAS CROSSED
THE REGION. THE CYCLONE IS NOW DEEPENING AND INTENSIFYING OVER NEW
BRUNSWICK /984 HPA/. SOME GUSTY WINDS ARE IMPACTING PARTS OF THE
REGION WITH THE STRONG SFC PRESSURE GRADIENT BETWEEN THE DEPARTING
CYCLONE...AND HIGH PRESSURE OVER THE LOWER MS RIVER
VALLEY/SOUTHEAST. KALB HAD A PEAK WIND GUST OF 39 KTS /45 MPH/
BTWN 1-2 AM. THE CORE OF THE STRONGEST WINDS AT H850 OF 40-50 KTS
WILL BE OVER THE ERN HALF OF THE FCST AREA PRIOR TO 12Z. SOME
GUSTS OF 30-40 MPH WILL BE POSSIBLE ESPECIALLY PRIOR TO NOON...AS
THE SFC PRESSURE GRADIENT STARTS TO WEAKEN THEREAFTER.
THE CYCLONIC FLOW WILL CONTINUE WITH H850 TEMPS FALLING TO -18C TO
-13C FROM NORTHWEST TO SOUTHEAST OVER THE FCST AREA. IN THE W/NW
SOME MULTIBANDS OF LAKE EFFECT WILL CONTINUE TO BE POSSIBLE. THE
LATEST HRRR SHOWS A WEAKENING OF THE ACTIVITY TOWARDS 12Z. THE
CURRENT RADAR SHOWS SEVERAL NARROW MULTIBANDS OFF LAKE ONTARIO
IMPACTING THE WRN DACKS...W-CNTRL MOHAWK...AND NRN CATSKILLS.
THESE BANDS SEEM TO BE ENDURING SOME SHEAR AND DRY AIR INTRUDING.
NONETHELESS...LOCALLY A BURST OF WIND DRIVEN SNOW IS POSSIBLE
ESPECIALLY ACROSS THE WRN DACKS...W-CNTRL MOHAWK VALLEY...AND THE
SRN GREENS/BERKS...DUE TO THE W/NW UPSLOPE COMPONENT. THE LAKE
EFFECT ADVISORY FOR SRN HERKIMER WILL CONTINUE...IT GOES ALL THE
WAY TO 7 AM TOMORROW. THE ACTIVITY MAY SLIP SOUTH OF THE ADVISORY
AREA LATER TODAY BASED ON THE HRRR...BUT THE LOCAL HIRES WRF SHOWS
A COUPLE OF BANDS IN THE 300 DEG TRAJECTORY BOUNDARY LAYER
FLOW...AND ONE DOES GO THROUGH SRN HERKIMER...MONTGOMERY AND WRN
FULTON COUNTIES INTO THE PM. BOTH FORMS OF HIGH RESOLUTION
GUIDANCE SHOWS THE BANDS WEAKENING IN THE AFTERNOON...UNTIL A
SHORT-WAVE ARRIVES TONIGHT FROM THE GREAT LAKES REGION.
COLD...WINDY...AND PARTLY CLOUDY CONDITIONS WILL PERSIST TODAY FOR A
LARGE PORTION OF THE AREA WITH HIGH TEMPS ABOUT 15 DEGREES BELOW
NORMAL. EXPECT HIGHS IN THE TEENS AND L20S OVER THE SRN
DACKS...SRN GREENS...AND ERN CATSKILLS. MID AND U20S WILL BE
COMMON ELSEWHERE...EXCEPT FOR A FEW L30S IN THE MID HUDSON
VALLEY...SRN TACONICS...AND LITCHFIELD CTY CT.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
TONIGHT...THE AFOREMENTIONED IMPULSE IN THE CYCLONIC FLOW WILL MOVE
ACROSS THE REGION WITH SOME LAKE ENHANCED SNOW SHOWERS AND
FLURRIES. THE BOUNDARY LAYER FLOW SHOULD BACK INITIALLY FOR A
270-280 DEG TRAJECTORY FOR PERHAPS THE CNTRL PORTION OF HERKIMER
AND SW HAMILTON COS TO GET A LITTLE SNOW...BEFORE VEERING AGAIN INTO
THE WRN-CNTRL MOHAWK VALLEY AND NRN CATSKILLS. ANOTHER FEW INCHES
OF SNOW WILL BE POSSIBLE IN THESE LOCATIONS...AND A 3-6" TALLY FOR
THE ADVISORY AREA LOOKS FINE. CLOUDS WILL INCREASE FOR THE BULK OF
THE REGION WITH PERHAPS SOME FLURRIES FROM THE CAPITAL REGION
EASTWARD. THE MID LEVEL VORT MAX/SHORT-WAVE SHOULD MOVE DOWNSTREAM
BY FRI MORNING WITH THE INVERSION HEIGHTS STARTING TO LOWER TO
SQUASH THE LAKE EFFECT ACTIVITY. A COLD NIGHT IS EXPECTED WITH
MAINLY TEENS FOR LOWS FOR THE REGION...EXCEPT SOME SINGLE DIGITS
FOR THE SRN ADIRONDACK REGION....AND SRN GREENS.
FRIDAY...THE BIG SHOPPING DAY LOOKS MAINLY DRY WITH THE LAKE EFFECT
SNOW SHOWERS AND FLURRIES DWINDLING WITH A STRONG SFC ANTICYCLONE
RIDGING IN FROM SE ONTARIO...AND THE ERN GREAT LAKES REGION. THE
BEST CHC OF A STRAY SNOW SHOWER WILL BE OVER THE W-CNTRL MOHAWK
RIVER VALLEY...AND NRN CATSKILLS. H850 TEMPS WILL STILL BE A
LITTLE BELOW NORMAL WITH -12C TO -15C READINGS. MAX TEMPS MAY BE A
SMIDGE WARMER THAN THANKSGIVING WITH HIGHS IN THE U20S TO L30S IN
THE VALLEYS /EXCEPT THE MID HUDSON RIVER VALLEY WHERE A FEW M30S
WILL BE POSSIBLE/...AND MAINLY LOWER TO M20S OVER THE HIGH PEAKS.
FRIDAY NIGHT...A VERY COLD NIGHT WILL BE ON TAP...AS THE SFC HIGH
STRENGTHENS TO 1043 HPA OVER ERN NY ON THE NAM40. MOSTLY
CLEAR/CLEAR SKIES WITH LIGHT TO CALM WINDS WILL YIELD IDEAL
RADIATIONAL COOLING CONDITIONS WITH LOWS FORECASTED CLOSER TO THE
NAM MOS GUIDANCE. LOWS 5 ABOVE TO 5 BELOW ZERO OVER THE LAKE
GEORGE REGION...AND SRN DACKS. SINGLE DIGITS IN THE MOHAWK RIVER
VALLEY...NRN CATSKILLS...HELDERBERGS...SRN VT...N-CNTRL BERKS...AND
NRN SARATOGA REGION...LOWER TEENS IN THE CAPITAL
DISTRICT..TACONICS...SRN BERKS...MID HUDSON VALLEY...AND NW CT.
SATURDAY-SATURDAY NIGHT...DRY WEATHER WILL START THE WEEKEND WITH
TEMPS STILL RUNNING BELOW NORMAL BY 10-15 DEGS. THE SFC HIGH MOVES
DOWN STREAM OVER NRN NEW ENGLAND AND THE GULF OF MAINE. A LIGHT
S/SE BREEZE BEGINS LATE IN THE DAY. MOSTLY SUNNY SKIES EARLY ON
WILL GIVE WAY TO INCREASE MID AND HIGH CLOUDS IN THE WARM
ADVECTION REGIME. A CLIPPER LOW WILL BE APPROACHING FROM THE NRN
GREAT LAKES REGION...AND S-CNTRL ONTARIO. THE TIMING IS VARIABLE
ON THE GUIDANCE...AND SLIGHT CHC OF SNOW SHOWERS WAS PLACED IN THE
GRIDS AFTER MIDNIGHT. LOWS SATURDAY WILL BE MUCH WARMER THAN THE
PREVIOUS NIGHTS WITH TEENS TO THE NORTH OF THE MOHAWK RIVER
VALLEY/CAPITAL REGION...AND LOWER TO M20S TO THE SOUTH.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MUCH OF THE LONG TERM PERIOD IS EXPECTED TO BE DRY WITH THE MAIN
FEATURE FOR EARLY NEXT WEEK BEING A COASTAL LOW WHICH WOULD
POTENTIALLY IMPACT THE FA IN THE TUESDAY TO TUESDAY NIGHT TIME FRAME.
SUNDAY AND SUNDAY NIGHT...A CLIPPER TYPE SYSTEM WITH LIMITED
MOISTURE IS EXPECTED TO IMPACT THE FA AS IT TRACKS ACRS SRN CANADA
AND NRN NEW ENGLAND. HIGHS ON SUNDAY ARE EXPECTED TO RANGE FROM THE
LOWER 30S NORTHWEST TO MID 40S SOUTHEAST WITH LOWS SUNDAY NIGHT
GENERALLY IN THE 20S TO AROUND 30.
MONDAY AND MONDAY NIGHT...LOOK TO BE DRY AS HIGH PRESSURE BRIEFLY
BUILDS BACK INTO THE FA. HIGHS ARE EXPECTED TO BE IN THE 30S TO
AROUND 40 WITH SOME UPPER 20S ACROSS THE WESTERN ADIRONDACKS. LOWS
ARE EXPECTED TO BE IN THE MID TEENS TO UPPER 20S.
TUESDAY AND TUESDAY NIGHT...A COASTAL LOW MAY IMPACT THE FA AS IT
WORKS NORTHWARD UP THE EASTERN SEABOARD TUESDAY AND INTO THE GULF OF
MAINE BY LATE TUESDAY NIGHT. TOO FAR OUT TO GET VERY SPECIFIC AT THIS
POINT IN TIME...BUT WILL INCLUDE CHANCE POPS IN THE FORECAST FOR
NOW. EXPECT HIGHS ON TUESDAY IN THE UPPER 20S TO UPPER 30S WITH LOWS
TUESDAY NIGHT IN THE MID TEENS TO MID 20S.
WEDNESDAY...AT THIS TIME LOOKS TO BE A DRY DAY AS COASTAL SYSTEM
DEPARTS EAST OF THE CANADIAN MARITIMES AND A RIDGE OF HIGH PRESSURE
BUILDS SOUTHEAST FROM NORTH OF THE UPPER GREAT LAKES. EXPECT HIGHS
ON WEDNESDAY TO BE IN THE MID 20S TO UPPER 30S.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH THE
END OF THE TAF PERIOD ENDING AT 06Z FRI. SKIES WILL GENERALLY BE
OVC035-080 THROUGH THE OVERNIGHT AND THEN SCT025-035 SCT100 ON
THURSDAY AND THEN BECOME SKC THU EVENING.
THE WEST-NORTHWEST WINDS TOO WILL BE ON THE INCREASE AS PRESSURE
GRADIENT REMAINS TIGHT. AS MIXING LAYER HEIGHTS INCREASE DURING
THURSDAY...WIND GUSTS WILL INCREASE TO AROUND 30 KTS. THE WINDS
WILL GRADUALLY DIMINISH THU EVENING BECOMING LIGHT AND VARIABLE
AFTER DARK.
OUTLOOK...
THURSDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
FRIDAY TO SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
SUNDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...SHSN.
SUNDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...SHSN.
&&
.HYDROLOGY...
THE RIVERS HAVE CRESTED...AND FLOWS ARE STARTING TO DECREASE WITH
THE COLDER TEMPS. THE TREND THE NEXT 5 DAYS ARE FOR FLOWS TO
DECREASE IN THE COLD AND DRY AIR MASS INTO THE HOLIDAY WEEKEND.
ANY PRECIP WILL BE IN THE FORM OF SNOW SHOWERS PREDOMINANTLY WEST
OF THE HUDSON RIVER VALLEY TODAY INTO FRIDAY. A CLIPPER LOW MAY
BRING SOME SCT SNOW SHOWERS TO THE REGION TO CLOSE THE WEEKEND
WITH VERY LIGHT QPF. MOST LOCATIONS OUTSIDE OF THE FAVORED LAKE
EFFECT AREAS ARE NOT EXPECTED TO RECEIVE A TENTH OF AN INCH OF
LIQUID EQUIVALENT THE NEXT 5 DAYS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST FRIDAY FOR NYZ038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...11
AVIATION...11
HYDROLOGY...JPV/WASULA
AREA FORECAST DISCUSSION
NWS MIAMI FL
1243 AM EST THU NOV 28 2013
.AVIATION...VFR WILL PREVAIL. SKIES WILL BE SKC AT KAPF THROUGH
THE PERIOD AND SKC-FEW050 EAST COAST THROUGH EARLY AFTERNOON,
BEFORE STRATO CU MOVES ONSHORE FROM THE ATLANTIC. EXPECTING BKN050
TO PREVAIL EAST COAST TERMINALS LATE AFTERNOON AND THU NIGHT.
MOISTURE LOOKS TOO SHALLOW TO ADD ANY SHOWER MENTION. WINDS WILL
PREVAIL NW AT NEAR 10 KT. GFS/NAM MOS LIKELY BRINGING WINDS OUT OF
THE NE TOO QUICKLY ATLANTIC TERMINALS. HRRR LOOKS TO HAVE THE
RIGHT IDEA, DELAYING NE WINDS UNTIL 18-19Z. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 654 PM EST WED NOV 27 2013/
UPDATE...
EXPANDED THE SMALL CRAFT ADVISORY ACROSS THE GULF AND ATLANTIC
WATERS TO INCLUDE LAKE OKEECHOBEE WITH LAKE SENSORS INDICATING
WINDS IN EXCESS OF 20 KNOTS ACROSS PORTIONS OF THE LAKE. AFTER 06Z
THURSDAY WINDS ARE FORECAST TO SLOWLY SUBSIDE...SO WILL LET THE
ADVISORY FOR THE LAKE EXPIRE AT THAT TIME. FOR THE GULF
WATERS...WINDS WILL REMAIN AROUND 20 KNOTS INTO THURSDAY WITH SEAS
OF 8 TO 10 FEET POSSIBLE MAINLY ACROSS THE OFF SHORE WATERS INTO
EARLY THURSDAY AND SLOWLY SUBSIDING INTO THURSDAY AFTERNOON. BASED
ON THE CURRENT FORECAST THE SMALL CRAFT ADVISORY WAS EXTENDED TO
18Z THURSDAY. FOR THE ATLANTIC WATERS...WINDS TO NEAR 20 KNOTS
WILL CONTINUE OVER NIGHT AND SLOWLY SUBSIDE LATER ON THURSDAY. AS
WINDS BECOME MORE NORTHERLY EARLY THURSDAY GULF STREAM SEAS WILL
SLOWLY INCREASE WITH SEAS TO NEAR 7 FEET POSSIBLE BY EARLY
THURSDAY. THE SMALL CRAFT ADVISORY FOR THE ATLANTIC WATERS WAS
ALSO EXTENDED TO 18Z THURSDAY.
60
PREV DISCUSSION... /ISSUED 637 PM EST WED NOV 27 2013/
AVIATION...
SKIES SHOULD REMAIN MOSTLY CLEAR FOR THE EAST COAST TAF SITES
OVERNIGHT. STRATUS AROUND 5KFT WAS MOVING ACROSS THE GULF
WATERS...AND SOME OF THIS WILL MOVE ACROSS KAPF OVERNIGHT. WINDS
WILL SHIFT TO THE NORTH AND NORTHEAST AROUND 10 KNOTS WITH HIGHER
GUSTS THANKSGIVING DAY. SCT/BKN STRATUS AROUND 4KFT WILL MOVE
INTO THE EAST COAST AREAS IN THE AFTERNOON.
PREV DISCUSSION... /ISSUED 222 PM EST WED NOV 27 2013/
DRY AND COOLER CONDITIONS FOR SOUTH FLORIDA ON THANKSGIVING....
SHORT TERM...
A COLD FRONT OVER THE EASTERN PORTION OF SOUTH FLORIDA WILL
CONTINUE TO PUSH EAST THIS AFTERNOON AND SHOULD BE OVER THE
BAHAMAS BY THIS EVENING. THE FRONT WILL CONTINUE TO MOVE EAST
FURTHER INTO THE ATLANTIC WATERS TONIGHT INTO THANKSGIVING DAY
AS HIGH PRESSURE OVER THE CENTRAL UNITED STATES MOVES SOUTHEAST
INTO THE SOUTHEASTERN UNITED STATES. THIS WILL ALLOW FOR DRIER AND
COOLER AIR TO WORK INTO THE AREA FROM THE NORTH TONIGHT INTO
THANKSGIVING DAY...WHICH IN TURN WILL ALLOW FOR THE LOWS TONIGHT
TO FALL DOWN INTO THE 40S OVER THE OVER MOST OF SOUTH FLORIDA
EXCEPT AROUND 40 WEST OF LAKE OKEECHOBEE AND AROUND 50 OVER THE
SOUTHEASTERN METRO AREAS OF SOUTH FLORIDA. THE WINDS WILL ALSO BE
AROUND 5 TO 10 MPH OVER THE METRO AREAS TO AROUND 5 MPH OVER THE
INTERIOR AREAS. THIS WILL ALLOW FOR THE WIND CHILLS TO FALL DOWN
INTO THE LOWER TO MID 40S OVER MOST OF SOUTH FLORIDA LATE
TONIGHT...EXCEPT UPPER 40S TO NEAR 50 OVER METRO BROWARD AND METRO
MIAMI-DADE COUNTIES.
THE HIGH WILL MOVE SLOWLY EAST INTO THE MID ATLANTIC WATERS THIS
WEEKEND ALLOWING FOR THE WIND FLOW TO SWING TO A NORTHEAST
DIRECTION. THIS WILL ALLOW FOR SOME SLOW WARMING IN THE
TEMPERATURES THIS WEEKEND OVER SOUTH FLORIDA. HIGHS ON THURSDAY WILL
BE IN THE 70S BEFORE INCREASING TO THE LOWER TO MID 80S BY THIS
WEEKEND. LOWS ON THANKSGIVING NIGHT WILL BE IN THE 50S TO NEAR 60
BEFORE INCREASING TO THE 60S TO NEAR 70 THIS WEEKEND.
THE WEATHER WILL ALSO BE MOSTLY DRY ACROSS SOUTH FLORIDA THIS
WEEKEND DUE TO THE HIGH NORTH OF THE AREA MOVING SLOWLY EAST. THE
ONLY EXCEPTION TO THIS IS OVER THE EAST COAST METRO AREAS WHERE A
FEW SHOWERS COULD OCCUR ON THE NORTHEAST WIND FLOW. SO WILL KEEP A
10 PERCENT POPS IN PLACE FOR THE EAST COAST METRO AREAS FOR THIS
WEEKEND.
LONG TERM...
THE HIGH WILL CONTINUE TO MOVE EAST INTO THE ATLANTIC WATERS EARLY
NEXT WEEK ALLOWING FOR ANOTHER COLD FRONT CURRENTLY OVER THE
NORTHWEST PORTION OF THE UNITED STATES TO MOVE SOUTHEAST AND
THROUGH SOUTH FLORIDA. THIS FRONT WILL BRING A SLIGHT CHANCE OF
SHOWERS TO THE EARLY NEXT WEEK...BEFORE DRY WEATHER WORKS BACK
INTO THE AREA FROM THE NORTH.
AVIATION...
VFR CONDITIONS WILL PREVAIL FOR NEXT 24 HOURS AS HIGH PRESSURE
BUILDS SOUTH INTO THE REGION. NORTHWEST WINDS OF 15-25 KTS TODAY
WILL DIMINISH TO 10 KTS OVERNIGHT...BUT INCREASE AGAIN THURSDAY TO
15-20 KTS. WINDS SHOULD ALSO VEER TO NORTH-NORTHEAST BY MID-MORNING
THURSDAY.
MARINE...
THE WINDS WILL BE NORTHERLY DIRECTION TONIGHT BEFORE SWINGING TO A
NORTHEAST DIRECTION ON THANKSGIVING DAY...AND REMAIN AT A
NORTHEAST DIRECTION THIS WEEKEND. THE WIND SPEEDS WILL ALSO REMAIN
AT LEAST 20 KNOTS OVER THE MOST OF THE LOCAL WATERS...EXCEPT 15
TO 20 KNOTS OVER BISCAYNE BAY AND LAKE OKEECHOBEE TONIGHT THROUGH
FRIDAY NIGHT. THIS WILL KEEP THE SEAS IN THE ATLANTIC WATERS AT 5
TO 7 FEET TONIGHT INTO FRIDAY NIGHT. FOR THE GULF SIDE...THE SEAS
WILL BE 5 TO 7 FEET UP TO 10 FEET IN THE OFFSHORE WATERS TONIGHT
BEFORE SLOWLY DECREASING TO LESS THAN 7 FEET BY THANKSGIVING
NIGHT. SO WILL CONTINUE THE SCA FOR BOTH THE ATLANTIC AND GULF
WATERS OF SOUTH FLORIDA FOR TONIGHT WITH A SCEC FOR BISCAYNE BAY
AND LAKE OKEECHOBEE WATERS.
FIRE WEATHER...
THE RELATIVE HUMIDITY VALUES ON THANKSGIVING DAY SHOULD REMAIN ABOVE THE
35 PERCENT CRITICAL VALUE OVER SOUTH FLORIDA. HOWEVER...SOME
ISOLATED AREAS OVER THE INTERIOR AND METRO AREAS OF COLLIER COUNTY
COULD FALL DOWN CLOSE TO THE 35 PERCENT CRITICAL VALUE DURING THE
AFTERNOON HOURS. AT THIS TIME...THE ENERGY RELEASE COMPONENT WILL
REMAIN IN THE LOWER 20S FOR THANKSGIVING DAY AND THE 20 FOOT WINDS
WILL REMAIN BELOW 15 MPH. SO WILL NOT BE ISSUING ANY FIRE WEATHER
WATCH OR RED FLAG WARNINGS FOR COLLIER COUNTY OR REST OF SOUTH
FLORIDA FOR THANKSGIVING DAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 64 77 69 80 / - 10 10 10
FORT LAUDERDALE 66 78 71 80 / - 10 10 10
MIAMI 67 79 71 81 / - 10 10 10
NAPLES 56 79 61 81 / - - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...RIP CURRENT RISK UNTIL 7 AM EST THIS MORNING FOR COASTAL COLLIER.
AM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING
FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS.
SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING
FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 1 AM EST EARLY THIS MORNING FOR LAKE
OKEECHOBEE.
GM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
310 AM CST THU NOV 28 2013
.DISCUSSION...
306 AM CST
THE PRIMARY FORECAST CONCERNS ARE CENTERED ON CLOUD COVER AND
TEMPERATURES THROUGH THE WEEKEND AND THEN CHANCES FOR PRECIPITATION
NEXT WEEK IN WHAT APPEARS TO POSSIBLY BE AN UNSETTLED
PATTERN...ALTHOUGH A HIGH DEGREE OF UNCERTAINTY.
ONE MORE SHORT WAVE IS DIVING SOUTHEAST ACROSS THE GREAT LAKES THIS
THANKSGIVING MORNING IN WHAT HAS BEEN A LITERAL PARADE OF THESE
COLD-AIR-REINFORCING SYSTEMS. A 1017MB SURFACE LOW REFLECTION ACROSS
IA WILL TRANSLATE EAST THIS MORNING AND WEAKEN AS IT DOES SUCH.
MORNING CLOUDS IN PLACE WERE DEVELOPED WITHIN THE WARM AIR ADVECTION
ENVELOPE OF THIS SYSTEM AND AS SUCH HAVE BASES MAINLY ABOVE 5000
FT...SO BELIEVE THEY WILL VACATE BY AFTERNOON ACROSS THE WESTERN AND
SOUTHERN FORECAST AREA GIVEN THE CLOUD-BEARING WIND FLOW. LOW-LEVEL
LAPSE RATES ARE MODESTLY STEEP BEHIND THE SYSTEM WITH SOME MARGINAL
SATURATION FORECAST AT THE TOP OF THE MIXED LAYER...SO LIKELY SOME
SCATTERED STRATOCU WILL CONTINUE. ALL-IN-ALL...EXPECTING SOME SUN
LATE THIS MORNING AND AFTERNOON. GIVEN THE 850MB AND 925MB FORECAST
TEMPS BY THE RAP AND NAM THIS AFTERNOON...WE ONCE AGAIN ARE IN THE
BOTTOM TENTH PERCENTILE FOR THIS TIME OF YEAR. THIS FAVORS HIGHS IN
THE LOWER TO MID 30S. SEE THE CLIMATE DISCUSSION BELOW FOR MORE ON
WHERE THIS STACKS UP FOR THANKSGIVING DAYS.
AS A CANADIAN SURFACE HIGH MOVES OVERHEAD TONIGHT TEMPERATURES
SHOULD RADIATE QUICKLY THIS EVE...EVEN IF IT DOES TAKE A FEW HOURS
AFTER SUNSET TO DIMINISH THE LINGERING STRATOCU. HAVE MID AND EVEN
PATCHY LOWER TEENS IN OUTLYING AREAS. AS THE WIND FIELD OVER LAKE MI
SHIFTS MORE NE TONIGHT IMMEDIATELY AHEAD OF THE HIGH CENTER...A LAKE
PLUME OF AT LEAST CLOUDS LOOKS LIKELY INTO NORTHWEST INDIANA AND
POSSIBLY NORTHEAST ILLINOIS. LAKE-INDUCED EQUILIBRIUM LEVELS AROUND
4500 FT FORECAST BY THE NAM SEEM A LITTLE SHALLOW FOR PRECIP AND ANY
PRONOUNCED CONVERGENCE IS UNLIKELY. HAVE THUS ONLY ADDED A LOW
CHANCE FOR SOME LIGHT SNOW IN NORTHWEST IN/FAR SOUTHEAST COOK COUNTY
LATE TONIGHT AS WELL AS BUMPED UP CLOUD COVER.
A MORE ZONAL PATTERN WILL MOVE OVER BY LATER FRIDAY INTO SATURDAY
BRINGING MODERATING TEMPERATURES. THERE IS A FAIR AMOUNT OF SPREAD
IN THE ENVELOPE OF GUIDANCE SOLUTIONS FOR HOW WARM SATURDAY WILL
BE...AND POTENTIAL CLOUD COVER LIKELY HAS QUITE A BIT TO DO WITH
THAT. THIS TIME OF YEAR SOUTHERLY LOW-LEVEL FLOW AFTER A COLD AIR
MASS CAN READILY BECOME "CONTAMINATED" WITH SATURATION/CLOUDS.
CLIMATOLOGY OF THE 850MB AND 925MB TEMPERATURES WOULD FAVOR MID AND
MAYBE EVEN UPPER 40S...BUT THAT WARM CURRENTLY SEEMS UNLIKELY WITH
AT LEAST SOME POTENTIAL FOR CLOUDS AND NOT THE STRONGEST OF WARM AIR
ADVECTION SIGNALS. THE HEART OF THE SYSTEM IS OVER THE NORTHERN
GREAT LAKES...SO FORCING AND SATURATION REMAINS MINIMAL OVER THE
AREA. SO HAVE NO POPS AT THIS TIME.
NEXT WEEK THE UNCERTAINTY REALLY STARTS TO RAMP UP BY MIDWEEK AFTER
WHAT IS BECOMING A MORE FAVORED DRY SUNDAY AND MONDAY. ALTHOUGH MUCH
LIKE SATURDAY...TEMPERATURE CONFIDENCE IS FAIRLY LOW GIVEN CLOUD
POTENTIAL. IF CLOUDS ARE REMAINING INTO SUNDAY MORNING THEY VERY
WELL COULD STICK AROUND ALL THE WAY THROUGH MONDAY NIGHT AS SURFACE
PRESSURES ARE FORECAST TO BASICALLY REMAIN THE SAME...I.E. LITTLE
ADVECTION. THE LONG ADVERTISED UPPER TROUGH ACROSS THE WEST COAST
LOOKS TO EVOLVE IN THE BEGINNING OF THE WEEK AND FORCE DOWNSTREAM
RIDGING AND SOUTHWEST FLOW ALOFT. THIS TROUGH SHOULD PACK QUITE A
PUNCH OF COLD AIR INTO THE NORTHERN ROCKIES AND PLAINS...BUT THE
MAIN BAROCLINIC ZONE DURING MIDWEEK LOOKS TO REMAIN TO THE NORTHWEST
AND IF THAT IS THE CASE THEN ANY HEAVY WINTER PRECIP SHOULD AS WELL
DURING MIDWEEK...BUT AGAIN CONFIDENCE IS LOW. ENERGY THAT TRANSLATES
EAST FROM THIS TROUGH APPEARS TO BE IN PARTS AND THUS MULTIPLE
CHANCES FOR PRECIP LOOK TO BE THE CASE ACROSS THE GREAT LAKES AND
CORN BELT REGIONS DURING THE DEC 3-8 PERIOD. NIGHTTIME TEMPERATURES
SHOULD BE MORE NEAR NORMAL OR EVEN ABOVE NORMAL GIVEN CLOUD
COVER DURING MIDWEEK...BUT DAYTIME HIGHS COULD BE ANYWHERE IN A
LARGE SPECTRUM OF SOLUTIONS DEPENDING ON STRENGTH OF SOUTHERLY
FLOW AND WHEN LOW PASSAGES OCCUR. THOSE ARE BOTH VARIABLES DIFFICULT
TO LOCK DOWN IN A FORECAST PATTERN OF A BROAD TROUGH IN THE WEST.
MTF
&&
.CLIMATE...
306 AM CST
THE FORECAST HIGH TODAY FOR CHICAGO (O`HARE) IS 33 WHICH WOULD TIE
MULTIPLE THANKSGIVINGS IN THE PAST TWO DECADES FOR A COOL
HIGH...THE LAST BEING 2007. HOWEVER IF THE MERCURY STAYS BELOW
THAT...IT WOULD BE THE COLDEST HIGH TEMPERATURE ON THANKSGIVING IN
CHICAGO SINCE 1989.
SIMILARLY FOR ROCKFORD...THE 31 DEGREE FORECAST HIGH WOULD BE THE
COOLEST THANKSGIVING HIGH SINCE 1995 AND IF IT STAYS BELOW THAT IT
WOULD BE THE COOLEST SINCE 1989.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* WIND SHIFT FROM SOUTHWEST TO NORTHWEST TOWARD 21Z WITH COLD
FRONTAL PASSAGE.
* CHANCE FOR BRIEF PERIOD OF MVFR CIGS MID TO LATE AFTERNOON.
MDB
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE RIDGING IS CROSSING THE AREA TONIGHT ALLOWING FOR
LIGHT SOUTHWEST WINDS TO SET UP ACROSS THE TERMINALS. WINDS WILL
LIKELY TURN MORE TO THE SOUTH LATER TONIGHT AS THE RIDGE SHIFTS
EAST AND A WEAK LOW APPROACHES FROM THE WEST. AN UPPER LEVEL
TROUGH WILL PASS NORTH OF THE AREA THROUGH THE MORNING BUT
ASSOCIATED MVFR CIGS AND SNOW SHOWERS WILL REMAIN NORTH OF THE
TERMINALS. BEYOND THAT...A COLD FRONT WILL BE DRAGGED ACROSS THE
AREA WITH THE SURFACE LOW WHICH WILL TURN WINDS TO THE NORTHWEST
DURING THE EARLY TO MID AFTERNOON HOURS. THERE WILL BE AT LEAST
SOME CHANCE FOR A BAND OF MVFR CIGS TO ACCOMPANY THE FRONTAL
PASSAGE SO WILL NEED TO MONITOR THE EXTENT SHOULD IT DEVELOP
HOWEVER THE DURATION LOOKS TO BE RATHER SHORT IF IT DOES. HIGH
PRESSURE WILL THEN MOVE IN INTO FRIDAY MORNING ALLOWING FOR LIGHT
NORTHERLY WINDS.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* LOW-MEDIUM CONFIDENCE THAT SOME MVFR CIGS WILL DEVELOP DURING
THE AFTERNOON.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY AND SATURDAY...VFR.
SUNDAY AND MONDAY...MVFR CIG POSSIBLE.
TUESDAY...VFR.
ALLSOPP
&&
.MARINE...
221 AM CST
THE MAIN FOCUS OF THE FORECAST CONTINUES TO BE THE POTENTIAL FOR
GALE FORCE WINDS LATE FRIDAY NIGHT THROUGH MIDDAY/EARLY AFTERNOON
SATURDAY...MAINLY ACROSS THE NORTH HALF OF THE LAKE.
CURRENTLY...SURFACE LOW PRESSURE CONTINUES TO DEEPEN AS IT MOVES
NORTHWARD INTO EASTERN QUEBEC AND NEWFOUNDLAND. HIGH PRESSURE
RIDGING IS CROSSING LAKE MICHIGAN EARLY THIS MORNING WITH A WEAK
AREA OF LOW PRESSURE OVER WESTERN MINNESOTA AND NORTHWEST IOWA.
THIS LOW WILL MOVE ACROSS NORTHERN LAKE MICHIGAN LATER TODAY AND
THIS EVENING. WINDS HAVE TURNED WEST AND SOUTHWEST THANKS TO THE
PASSAGE OF THE RIDGE AXIS WITH SPEEDS DIMINISHING BUT THEY WILL
INCREASE SOMEWHAT AS THE LOW CROSSES THE AREA LATER TODAY. A
NARROW CORRIDOR OF OFFSHORE SOUTHEASTERLY WINDS IS OCCURRING ALONG
THE MICHIGAN SHORE BUT WILL DIMINISH THROUGH MID MORNING. WINDS
ACROSS FAR NORTHERN LAKE MICHIGAN WILL BE TRICKY AS THE LOW CENTER
IS EXPECTED TO CROSS THIS AREA THIS AFTERNOON. THIS WILL LIKELY
LEAD TO AN EASTERLY SURFACE FLOW OVER FAR NORTHERN LAKE MICHIGAN
LATER THIS MORNING AND THIS AFTERNOON...WHILE THE REST OF THE LAKE
SEES WEST TO SOUTHWEST WINDS. A COOL FRONTAL BOUNDARY WILL CROSS
THE LAKE LATER TODAY TURNING WINDS TO THE NORTHWEST. HIGH PRESSURE
WILL SPREAD IN BEHIND THE FRONT AND STRENGTHEN AS IT CROSSES THE
LAKE FRIDAY BEFORE SHIFTING TO THE EAST. THIS WILL TURN WINDS BACK
TO THE SOUTH BY FRIDAY AFTERNOON WITH RATHER LIGHT SPEEDS.
THE HIGH WILL CONTINUE TO STRENGTHEN AS IT MOVES ACROSS THE NORTHEAST
U.S. WHILE A CLIPPER DROPS SOUTHEAST ACROSS WESTERN ONTARIO JUST
NORTH OF LAKE SUPERIOR SATURDAY. THE PRESSURE GRADIENT WILL TIGHTEN
BETWEEN THESE TWO SYSTEMS LEADING TO STRONG SOUTH TO SOUTHWEST WINDS
LATE FRIDAY NIGHT AND SATURDAY MORNING. THE STRONGEST SPEEDS WILL
OCCUR ACROSS NORTHERN PORTIONS OF THE LAKE. WILL HOLD WINDS TO 30 KT
FOR NOW WITH THE STRONGEST WINDS NORTH...BUT AM CONCERNED THAT AN
INCREASE TO GALES MAY BE NEEDED. THIS SYSTEM IS NOT TOO UNLIKE
SEVERAL WHICH WE SAW EARLIER THIS FALL THAT FEATURED SURFACE LOWS
PASSING TO THE NORTH AND WINDS THAT WERE HIGHER THAN EXPECTED. THIS
MAY NOT BE THE CASE WITH THIS PARTICULAR SYSTEM BUT IT IS WORTH
NOTING GIVEN THAT UNSTABLE CONDITIONS WILL BE IN PLACE ACROSS THE
LAKE SIMILAR TO THESE EARLIER SYSTEMS. A COLD FRONT CROSSES THE
LAKE SATURDAY AFTERNOON ALLOWING WINDS TO DROP OFF SATURDAY
EVENING. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE REGION
SUNDAY AND CONTINUE TO KEEP LIGHTER WINDS IN PLACE THROUGH
TUESDAY. FORECAST CONFIDENCE DROPS OFF BY WEDNESDAY BUT IT DOES
APPEAR THAT A MORE ACTIVE PATTERN WILL BE SETTING UP BRINGING
INCREASING CHANCES FOR STRONGER WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM THURSDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1023 PM CST WED NOV 27 2013
.UPDATE...FOR 06Z AVIATION DISCUSSION BELOW
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 215 PM CST WED NOV 27 2013
EARLY AFTERNOON WATER VAPOR IMAGERY TOGETHER WITH GFS 27.12 HEIGHTS
AND WINDS IMMEDIATELY IDENTIFIED A LONG WAVE TROUGH ACROSS THE
EASTERN CONUS...WITH A CYCLONE DOWNSTREAM OF THIS TROUGH AXIS.
NORTHWEST FLOW PREVAILED ACROSS THE CENTRAL CONUS UPSTREAM OF THE
TROUGH AXIS. A WEAK SHORTWAVE ALONG THE ND/MN BORDER WAS EMBEDDED IN
THIS NORTHWEST FLOW. WARM AIR ADVECTION AHEAD IF THIS SHORTWAVE
TOGETHER WITH THE UPPER LEVEL DYNAMICS ASSOCIATED WITH THE 5M/HR
HEIGHT FALLS WERE THE DRIVING FORCE BEHIND AN AREA OF SNOW ACROSS
NORTHERN MINNESOTA.
THIS EVENING THE FORCING WILL WEAKEN...BUT SNOW SHOULD CONTINUE TO
SPREAD SOUTHEASTWARD INTO NORTHERN WISCONSIN. THE NORTHEASTERN
COUNTIES IN THE CWA WILL BE RIGHT ON THE EDGE OF THIS SNOW...BUT
FORECAST SOUNDINGS FOR EAU CLAIRE AND NEW RICHMOND WOULD SUPPORT AT
LEAST A FEW HOURS OF SNOW. THE LOW LEVEL DRY AIR WILL DELAY THE
ONSET UNTIL CLOSER TO 00Z THIS EVENING. SNOW TOTALS WILL BE LESS
THAN AN INCH...AND SHOULD TAPER OFF TO FLURRIES BY THURSDAY MORNING.
THE CHALLENGE FOR THURSDAYS FORECAST WAS THE CLOUD COVER. INCREASED
IT SLIGHTLY BASED OFF THE 0-1RH FROM BOTH THE NAM AND RAP WHICH SEEM
TO HAVE A GOOD HANDLE ON THE STRATUS CURRENTLY ENTERING NORTHERN
NORTH DAKOTA. ALSO LOWERED HIGH TEMPS A COUPLE OF DEGREES BECAUSE OF
THE INCREASED CLOUD COVER.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 215 PM CST WED NOV 27 2013
BIG CHGS ARE EXPECTED NEXT WEEK AS A SIGNIFICANT ARCTIC AIR MASS
SURGES SOUTHWARD ACROSS THE WESTERN CONUS...AND EVENTUALLY TAKING
HOLD OF MOST OF THE U.S...WITH THE EXCEPTION IN THE DEEP SE.
CURRENT LONG WAVE PATTERN REMAINS FROM THE NW ACROSS THE UPPER
MIDWEST ALONG WITH A SPLIT FLOW REGIME FOR THE REMAINDER OF THE
CONUS. THE SOUTHERN STREAM HAS BEEN THE MOST ACTIVE IN RECENT
WEEKS...TAKING THE BULK OF THE SIGNIFICANT WX TRACKS SOUTH AND
EAST OF THE UPPER MIDWEST. ALTHOUGH SOME TIMING AND STRENGTH
PARAMETERS REMAIN UNCLEAR IN THE DETERMINISTIC RUNS FROM BOTH THE
EC/GFS...THERE REMAINS ONE THEME...A SIGNIFICANT COLD AIR MASS
WILL INVADE MOST OF THE U.S. STARTING THIS WEEKEND IN THE PACIFIC
NW...AND EVENTUALLY THE ROCKIES/PLAINS/GREAT LAKES BY THE
FOLLOWING WEEKEND.
USUALLY MODELS ARE TOO FAST ON PATTERN CHGS...AND THIS IS EVIDENT
WITH EACH MODEL RUN. ALTHOUGH THE EC HAS BEEN THE STRONGEST ON THE
DEEP TROUGH DEVELOPING ACROSS MOST OF THE WESTERN/CENTRAL PART OF
THE U.S. BY LATE NEXT WEEK...THE ENSEMBLE MEANS /EC & GFS/ HAVE
CONTINUED TO KEEP A MORE PROGRESSIVE WX PATTERN. EVEN THE LATEST
EC 12Z/27 RUN HAS A MORE PRONOUNCED DEEP TROUGH ACROSS THE
NORTHERN ROCKIES BY THE END OF NEXT WEEK COMPARED TO THE 50H
ENSEMBLE MEAN.
BASICALLY WITH THE STRONGER AND DEEPER TROUGH...STORM SYSTEMS WILL
LIKELY BE SLOWER ON THE ONSET OF SFC LOW /BOMBS/ DEVELOPING ACROSS
THE PLAINS. OVER THE PAST 3-5 RUNS OF THE EC...THE SFC LOW AND
ASSOCIATED ARCTIC BOUNDARY KEEPS GETTING PUSHED BACK IN TIME ON
THE EVOLUTION OF A STRONG STORM SYSTEM IN THE PLAINS. THIS WILL
LIKELY KEEP OUR REGION UNEVENTFUL UNTIL LATE IN THE PERIOD...AND
POSSIBLY OUTSIDE OUR 7 DAY FORECAST IF THE TROUGH IN THE WEST
CONTINUES TO DEEPEN. IN ADDITION TO THE SLOWER PACE OF THE STORM
SYSTEM MOVING OUT INTO THE PLAINS...THE LARGE AREA OF ARCTIC HIGH
PRESSURE CIRCULATING FROM THE EASTERN CANADA...AND ACROSS THE
GREAT LAKES /EAST & NE FLOW IN THE BOUNDARY LAYER/...KEEPS OUR
REGION RELATIVELY DRY. THEREFORE...I AM NOT CONFIDENT ON ANY CHC
OF PRECIPITATION NEXT WEEK UNTIL THIS SYSTEM MOVES OUT INTO THE
PLAINS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 1025 PM CST WED NOV 27 2013
A BKN-OVC DECK FROM 5KFT-7KFT WILL PREVAIL OVERNIGHT...AS MVFR
LEVEL CLOUDS APPROACH FROM THE NORTH/WEST. SAID CLOUDS ARE
EXPECTED TO ENTER WEST CENTRAL MN /KAXN/ BY DAYBREAK...AND
GRADUALLY SNAKE SOUTH AND EAST /TOWARD KRWF/ DURING THE MORNING.
THE CLOUDS SHOULD BECOME MORE TRANSPARENT DURING THE DAYTIME
HOWEVER...SO HAVE ONLY INCLUDED A SCATTERED GROUP AT KMSP...BUT KEAU/KRNH
LIKELY SEEING BKN-OVC MVFR CIGS THROUGH A GOOD PORTION OF THE DAY.
LIGHT AND VARIABLE WINDS OVERNIGHT BECOME WEST/NORTHWEST ON
THURSDAY AND INCREASE TO 10-15KTS IN THE WAKE OF THE TROUGH.
KMSP...
A 5000FT CIG WILL PREVAIL INTO THURSDAY...WITH A POSSIBILITY FOR MVFR
LEVEL CLOUDS BETWEEN 18Z THU AND 00Z FRI. HAVE INCLUDED A SCT
MENTION FOR NOW. LIGHT AND VARIABLE WINDS OVERNIGHT SHIFT TO THE NORTHWEST
BY 14Z THURSDAY /AND GUST TO AROUND 15KTS DURING THE AFTERNOON/.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS SE AT 5-10KTS.
SAT...VFR. SW WINDS AT 5-10KTS BECOMING W/NW DURING THE AFT/EVE.
SUN...VFR WITH MVFR AND -SN POSSIBLE LATE. WINDS E/SE AT 5KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...JLT
AVIATION...LS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
332 AM CST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST THU NOV 28 2013
OVERNIGHT UPPER AIR ANALYSIS INDICATES MID TO UPPER LEVEL
TROUGHING OVER THE EASTERN CONUS...WITH A RIDGE OVER THE WEST AND
A MID LEVEL LOW OVER THE PACIFIC OFF THE CALIFORNIA COAST. A
SUBTLE MID LEVEL PERTURBATION IS ALSO NOTED OVER SOUTHERN
MINNESOTA...MOVING SOUTHEAST. MID TO UPPER LEVEL JET ENERGY
EXTENDS FROM SOUTH CENTRAL CANADA...SOUTHEAST INTO THE CENTRAL
CONUS...AND FINALLY EAST AND NORTHEAST ALONG THE EASTERN CONUS
INTO SOUTHEASTERN CANADA. MID TO UPPER LEVEL FLOW OVER OUR AREA
MAXES OUT AT AROUND 70KTS BETWEEN 300MB AND 200MB PER 00Z SOUNDING
DATA FROM KLBF AND KOAX. WATER VAPOR IMAGERY INDICATES INCREASED
VALUES OF MID LEVEL MOISTURE EXTENDING ALONG THE BACK SIDE OF THE
WEST COAST RIDGE...AS WELL AS FROM THE PACIFIC EASTWARD INTO
MEXICO AND THE SOUTHERN PLAINS. MID LEVEL MOISTURE OVER OUR AREA
HOWEVER REMAINS FAIRLY LIMITED. AT THE SURFACE...AN AREA OF LOW
BAROMETRIC PRESSURE EXISTS OVER NORTHWEST IOWA JUST AHEAD OF THE
AFOREMENTIONED MID LEVEL PERTURBATION...WITH AN ASSOCIATED COLD
FRONT EXTENDING FROM WESTERN IOWA INTO SOUTHEASTERN NEBRASKA AND
NORTHERN KANSAS. THIS FRONT HAS CLEARED MOST ALL OF OUR CWA AND AS
A RESULT...THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM
THE NORTH/NORTHWEST.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST NORTHWESTERLY MID TO UPPER LEVEL FLOW WILL PERSIST OVER
OUR AREA THROUGH THE NEXT 24 HOURS AS THE EASTERN CONUS TROUGH AND
WESTERN CONUS RIDGE BOTH TREK EAST. THE MID LEVEL
PERTURBATION...CURRENTLY OVER SOUTHERN MINNESOTA...IS EXPECTED TO
CONTINUE MOVING SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH NO
OTHER MID LEVEL SHORTWAVES/PERTURBATIONS EXPECTED TO IMPACT THE
REGION. AT THE SURFACE...THE AREA OF LOW BAROMETRIC
PRESSURE...CURRENTLY OVER NORTHWEST IOWA...SHOULD ALSO CONTINUE
MOVING TO THE EAST/SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH THE
ASSOCIATED LOW LEVEL BAROCLINIC ZONE PUSHING FARTHER
SOUTH/SOUTHEAST ACROSS THE PLAINS. THE LOW LEVEL WIND FIELD ACROSS
OUR AREA SHOULD REMAIN FROM THE NORTH/NORTHWEST THROUGH MUCH OF
TODAY AS A RESULT. THAT BEING SAID...GUIDANCE SUGGESTS THE PASSAGE
OF A SURFACE RIDGE TO EAST SHOULD ALLOW FOR LOW LEVEL RETURN FLOW
ACROSS OUR AREA DURING THE OVERNIGHT HOURS TONIGHT.
WITH AN OVERALL LACK IN OMEGA EXPECTED OVER OUR AREA...DRY
CONDITIONS ARE CURRENTLY FORECAST THROUGH THE NEXT 24 HOURS.
SATELLITE IMAGERY INDICATES A BAND OF STRATUS OVER MUCH OF THE
NORTHERN PLAINS THIS MORNING AND THIS STRATUS IS ADVANCING TO THE
SOUTH...ABOUT 150 MILES NORTH OF THE AFOREMENTIONED SURFACE FRONT.
GUIDANCE FROM THE NAM AND RAP BOTH SHOW THIS STRATUS...WITH HIGH
RELATIVE HUMIDITY VALUES AT 925MB NOTED ON PLAN VIEW
MAPS...INFILTRATING OUR NORTH/NORTHEASTERN CWA JUST PRIOR TO
SUNRISE THIS MORNING...BUT DISSIPATING POST-SUNRISE AS DIABATIC
HEATING RESULTS IN INCREASED BOUNDARY LAYER HEIGHT AND MIXING.
WENT AHEAD AND PLAYED PRETTY CLOSE TO NAM AND RAP GUIDANCE FOR THE
CLOUD FORECAST THROUGH THE FIRST PART OF THE SHORT TERM FORECAST
PERIOD...WITH THIS STRATUS EXPECTED TO IMPACT OUR NORTH/NORTHEAST
BY 10Z OR 11Z THIS MORNING...AND THEN DISSIPATE BY 15Z OR 16Z.
WITH LOW LEVEL RETURN FLOW INFILTRATING THE REGION TONIGHT...THERE
ARE INDICATIONS OF ISENTROPIC UPGLIDE AND SATURATION...PRIMARILY
ALONG THE 275-285K SURFACES...OVER THE HIGH PLAINS OF KANSAS AND
NEBRASKA. ALTHOUGH IT APPEARS MUCH OF OUR CWA SHOULD BE SPARED
FROM ANY STRATUS DEVELOPMENT THROUGH 12Z FRIDAY...925MB RELATIVE
HUMIDITY PLAN VIEW MAPS FROM THE NAM...OPERATIONAL GFS AND EC ALL
SUGGEST OUR EXTREME WEST/SOUTHWEST COULD ACTUALLY OBSERVE QUITE A
BIT OF CLOUD COVER TOWARDS SUNRISE FRIDAY AS THE EASTERN PERIPHERY
OF THE HIGH PLAINS STRATUS CLIPS THE AREA. WENT AHEAD WITH A
BROKEN CEILING ACROSS OUR EXTREME WEST/SOUTHWEST BY 12Z FRIDAY AS
A RESULT.
THE INTRUSION OF A COOLER LOW LEVEL AIRMASS BEHIND THE LOW LEVEL
BAROCLINIC ZONE SHOULD RESULT IN A COOLER DAY TODAY WHEN COMPARED
TO WEDNESDAY. HIGH TEMPERATURES GENERALLY IN THE MID 30S ACROSS
OUR NORTH...AND INTO THE MID 40S ACROSS OUR SOUTH...ARE FORECAST
FOR TODAY AS A RESULT. IT MIGHT OTHERWISE BE REASONABLE TO THINK
TONIGHT WILL BE COOLER WHEN COMPARED TO EARLY THIS MORNING...BUT
WITH LOW LEVEL RETURN FLOW EXPECTED TO INFILTRATE OUR AREA DURING
THE OVERNIGHT HOURS...OVERNIGHT LOWS TONIGHT SHOULD ACTUALLY BE
PRETTY CLOSE TO WHAT WE ARE EXPECTING EARLY THIS MORNING.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CST THU NOV 28 2013
THE FIRST PART OF THE LONG TERM FORECAST IS DRY WITH ABOVE NORMAL
TEMPERATURES...AFTERWHICH A MORE UNSETTLED...COLDER AND MORE
CHALLENGING FORECAST TAKES HOLD BY MID NEXT WEEK.
A TRANSITIONING WEST/NORTHWEST UPPER LEVEL FLOW WILL KEEP THE
REGION MAINLY DRY AND MILD THROUGH THROUGH THE REMAINDER OF THE
HOLIDAY WEEKEND. REGIONAL TRAVEL CONCERNS WILL BE NIL...AND BOTH
DAYTIME HIGHS AND NIGHTTIME LOWS WILL BE AT OR SLIGHTLY ABOVE
SEASONAL NORMALS. ONE NOTABLE WEATHER ELEMENT WILL THE WIND...OR
LACK THERE OF ON SATURDAY AND SUNDAY. THAT WILL HELP OFFSET ANY
COOLING FROM PASSING CLOUDS THROUGHOUT THE WEEKEND.
OVERALL...PRETTY NICE FOR THE END OF NOVEMBER. WARM ADVECTION
ASSOCIATED WITH WAVE ACROSS THE NORTHERN PLAINS SUNDAY WILL
THICKEN CLOUDS...BUT NOT TOO EXCITED ABOUT INCURRING ANY
MEASURABLE PRECIPITATION AT THIS POINT.
ACTUALLY THE MILD WEATHER WILL CONTINUE INTO THE FIRST PART OF
NEXT WEEK...ALTHOUGH THINGS WILL BE CHANGING AS UPPER LEVEL
HEIGHTS LOWER AND WE START TO SEE UPPER LEVEL LOW PRESSURE DEEPEN
IN THE GREAT BASIN REGION. AS THE LOW STRENGTHENS...AN INCREASING
SOUTH TO SOUTHEAST FLOW ACROSS THE CENTRAL/SOUTHERN PLAINS
DEVELOPS WHICH WILL KEEP TEMPERATURES ON THE MILD SIDE
MONDAY/TUESDAY. THERE IS SOME MODEL LIKENESS IN OVERALL
TRENDS...BUT VERY UNEASY IN TRYING TO PIN DOWN ANY SPECIFIC
DETAILS FOR NEXT WEEKS FORECAST AT THIS POINT. WE HAVE BEEN
ANTICIPATING A COLD AIR PUSH NEXT WEEK...AND THAT STILL LOOKS ON
TRACK FOR ABOUT WEDNESDAY...BUT THE COLD AIR PLUNGE COMES IN
PIECES WITH THE COLDEST AIR NOT LIKELY TO MAKE IT INTO THE AREA
UNTIL LATER NEXT WEEK. MODELS SUGGEST HEAVIEST PRECIPITATION
TRENDS WILL LIKELY BE ACROSS THE DAKOTAS AT THIS POINT...WITH ONLY
SMALL CHANCES FOR RAIN OR RAIN/SNOW MIX IN THE FORECAST AT THIS
POINT AS THE SYSTEM APPROACHES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1133 PM CST WED NOV 27 2013
VFR CONDITIONS EXPECTED THROUGH 11Z...WITH MVFR CONDITIONS
FORECAST 11-18Z...FOLLOWED BY VFR CONDITIONS 18Z ONWARD.
LITTLE IN THE WAY OF CLOUD COVER WILL BE OBSERVED TO START THE TAF
PERIOD. STRATUS...CURRENTLY OVER SOUTH DAKOTA...IS SURGING TOWARD
THE AREA AND MAY IMPACT THE AREA TOWARDS SUNRISE THURSDAY. BASED
ON CURRENT OBSERVATIONS ACROSS SOUTH DAKOTA...AS WELL AS CURRENT
GUIDANCE...WENT AHEAD WITH A CEILING AROUND 1500FT AGL STARTING AT
11Z. THE SURFACE WIND WILL REMAIN FROM THE NORTH/NORTHWEST AT
AROUND 10KTS THROUGH THE OVERNIGHT HOURS AND INTO THURSDAY
MORNING...THEN BECOMING LIGHT AND VARIABLE HEADING INTO THE
AFTERNOON HOURS THURSDAY. VISIBILITY RESTRICTION IS NOT EXPECTED
AT GRI THROUGH THE NEXT 24 HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...NOAA/NWS/BRYANT
LONG TERM...NOAA/NWS/MORITZ
AVIATION...NOAA/NWS/BRYANT
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
131 AM EST THU NOV 28 2013
.SYNOPSIS...
A STORM SYSTEM OVER NEW ENGLAND WILL CONTINUE MOVING NORTHEAST
TONIGHT. STEADY SNOW WILL END THIS EVENING, BUT LAKE EFFECT SNOW
SHOWERS WILL SET UP ACROSS UPSTATE NEW YORK TONIGHT AND CONTINUE
INTO THANKSGIVING NIGHT. HIGH PRESSURE AND DRY WEATHER WILL RETURN
FRIDAY NIGHT TO SATURDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
920 PM UPDATE...
REDUCED OVERNIGHT SNOWFALL AMOUNTS IN PROJECTED BANDS FROM AROUND
2 TO 3 INCHES, DOWN TO 1.5 TO 2 INCHES. THIS IS MOSTLY FROM A
REDUCTION IN THE FIRST 6 HOURS, AS BAND INTO SYR AREA HAS NOT YET
SHOWN SIGNS OF FORMING. LATEST HRRR HAS A PRETTY GOOD HANDLE ON
THE RADAR DEPICTION, AND IT KEEPS THE RETURNS PRETTY LIGHT THROUGH
THE NEXT FEW HOURS.
STILL ANTICIPATE BAND INTENSIFICATION SOMETIME BETWEEN 7Z AND 9Z,
WITH MOST OF THE OVERNIGHT SNOW ACCUMULATION COMING IN THE FINAL 6
HOURS OF THE OVERNIGHT PERIOD.
515 PM UPDATE...
QUICK UPDATE TO LOWER POPS TO SLIGHT CHANCE OVER NY COUNTIES WEST
OF I-81 IN LOWER DEWPOINT ATMOSPHERE. BACK EDGE OF SYNOPTIC SNOW IS ALONG
THE I-81 CORRIDOR EASTWARD. WESTWARD - JUST A FEW RADAR RETURNS
AND MAJORITY OF OBS ARE REPORTING DRY WEATHER. AS THE EVENING
WEARS ON...THE EVENT WILL TRANSITION TO LAKE EFFECT OVER NORTHERN
FA.
3 PM UPDATE...
BACK EDGE OF SYNOPTIC PRECIP STILL IN NE PA AND THE CATSKILLS.
RAIN HAS NOW MOSTLY CHANGED TO SNOW. THIS WILL LIFT NE BY 6 PM AS
THE LARGE SFC LOW IN EASTERN NEW ENGLAND. NW FLOW ACROSS THE
ENTIRE CWA WITH WEAK LAKE EFFECT STARTING. AS THE LOW LEVEL FLOW
ALIGNS AND COLDER AIR COMES IN THE LAKE EFFECT SNOW WILL EXPAND IN
COVERAGE AND INCREASE IN INTENSITY. WITH A 320 FLOW IT WILL BE
MULTIBANDS. GEORGIAN BAY CONNECTION COMES INTO PLAY AS THE FLOW
SHIFTS SOME TO WNW. MOISTURE DEPTH OF 10KT. DENDRITE ZONE OF 2K FT
STARTS AROUND 6K THEN DROPS TO 4K LATE TONIGHT. GOOD LIFT THROUGH
THE MOISTURE AND DENDRITE ZONES. ISSUED A LES ADVISORY FOR
ONONDAGA ONEIDA MADISON FOR TONIGHT TO THU NGT.
OUTSIDE OF THE LAKE EFFECT IN CENTRAL NY...NE PA WILL BE CLOUDY
AND MOSTLY DRY. CAA IS STRONG WITH TEMPS FALLING UPPER TEENS AND
L20S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
3 PM UPDATE...
THU MORNING A LULL BEFORE A SHORT WAVE DROPS SE HELPING TO ENHANCE
THE LAKE EFFECT. LOW LEVEL FLOW SHIFTS TO 290 BRINGING THE BEST
BAND INTO SYRACUSE AND ONEIDA AND CAZENOVIA. THIS BAND WILL
CONTINUE INTO THE EVENING BEFORE WEAKENING LATE THU NGT. MULTILAKE
CONNECTION FROM GEORGIAN BAY. COULD BE A GOOD ENOUGH BAND FOR
HALF AN INCH TO AN INCH AN HOUR SNOW. HEAVIEST SNOW TOTALS THU PM
3 TO 5 INCHES.
FRIDAY COLD NW LOW LEVEL FLOW STILL GOING AS A LARGE DRY CANADIAN
HIGH PRESSURE MOVES IN FROM THE NW. LL FLOW BECOMES LIGHT AND IS
SHEARED SO SNOW ACCUMULATIONS WILL BE LESS THAN 2 INCHES
EVERYWHERE BEFORE LES SHUTS DOWN FRI AFTN. HIGH OVER THE CWA FRI
NGT AND STALLS INTO SAT NGT. WAA AT 850MB KICKS IN WHILE UPPER
LEVEL HEIGHTS RISE. SFC TEMPS STILL BELOW NORMAL AND MOSTLY BELOW
FREEZING.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
PD BEGINS WITH A WEAK WV DROPPING THRU THE GREAT LAKES. DFRNCS
BETWEEN THE EURO AND GFS WILL HAVE LTL EFFECT ON THE SENSIBLE WX
FOR THE SYSTEM WHICH LOOKS TO GENERATE SOME LGT PCPNSAT NGT INTO
SUNDAY. TEMPS MRGNL...BUT LOOKS COLD ENUF FOR SOME LGT SNOW MOST
PLACE...ESP NORTH. SLGTLY MILDER OVER NEPA BUT WITH A LWR CHANCE
PF PCPN IT MAY NOT MAKE MUCH DFRNC. SYSTEM, PASSES THRU SUN BUT
LEAVES THE AREA IN A SHALLOW UT BROAD UPR TROF OVER THE
LAKES...AND WEAK AREA OF MOISTURE PCPN. EURO SUGGESTS SOME WEAK
CSTL DVLPMT ON TUE PERHAPS ORGANIZING THE PCPN A BIT MORE. GFS HAS
DVLPMT FURTHER OUT TO SEA BUT STILL SOME ENHANCED PCPN OVER THE
ERN ZONES. HWVR...IN GNRL JUST A SEASONABLY COOL PD WITH LGT PCPN
AT TIMES.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A BRISK NORTHWEST FLOW WILL PREVAIL ACROSS THE AREA THROUGH THIS
TAF PERIOD WITH WIDESPREAD MVFR CIGS AND FLURRIES EXPECTED AT ALL
TERMINALS EXCEPT FOR KELM/KAVP WHERE CONDITIONS WILL BE PRIMARILY
VFR.
AT KSYR, A LAKE EFFECT SNOWBAND CONTINUES TO PRODUCE IFR
RESTRICTIONS NOW. IT APPEARS BASED ON RADAR AND MODEL SOUNDINGS
SHOWING DRIER AIR WORKING IN FROM ABOVE...THAT THE BEST SHOT FOR
IFR WILL COME OVER THE NEXT FEW HOURS. WITH THE 09Z UPDATE I MAY
HAVE TO REMOVE IFR VSBYS THAT WE CURRENTLY HAVE NEAR DAYBREAK.
LATER TODAY AS MOISTURE INCREASES IN THE COLUMN...MORE LAKE SNOWS
ARE POSSIBLE ESPECIALLY AT KRME AND KSYR WITH IFR VSBYS POSSIBLE.
NORTHWEST WINDS 10-15 KNOTS WITH GUSTS AROUND 25 KNOTS DIMINISHING
TO 10-12 KNOTS BY MID MORNING THURSDAY.
OUTLOOK...
THU NIGHT TO SUN MORN...MAINLY VFR.
SUN AFTN TO MON...MVFR AND MAYBE IFR IN MIXED PRECIP.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST FRIDAY FOR NYZ009-018-
036-037.
&&
$$
SYNOPSIS...TAC
NEAR TERM...DJP/TAC
SHORT TERM...TAC
LONG TERM...DGM
AVIATION...HEDEN/RRM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
300 AM CST THU NOV 28 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
NORTHWEST FLOW ALOFT WILL CONTINUE INTO FRIDAY...WITH ANOTHER
SHORTWAVE EXPECTED FRIDAY INTO FRIDAY NIGHT. 00Z MODELS INDICATE
THAT THIS NEXT SHORTWAVE WILL TRACK FURTHER NORTH THAN THE ONE
YESTERDAY...KEEPING ACCUMULATING SNOWFALL OUTSIDE OF THE FA.
FOR TODAY...THE REGION WILL BE BETWEEN SHORTWAVES AS HIGH PRESSURE
BUILDS FROM THE NORTH. THIS WILL LEAVE CLOUD TRENDS AS THE MAIN
CHALLENGE. 09Z SATELLITE IMAGERY SHOWS CLEARING WORKING INTO THE
NORTHERN VALLEY. MODELS ARE STRUGGLING WITH THE CURRENT CLOUD
COVER...ALTHOUGH THE 07Z RAP IS CLOSEST WHEN LOOKING AT THE 925MB-
850MB RH FIELD. THIS MODEL INDICATES THAT CLEARING WILL CONTINUE
TO MOVE DOWN THE VALLEY...WITH CLOUDS DISSIPATING ALONG BOTH
EDGES THROUGH THE DAY. THIS SCENARIO MAKES SOME SENSE WITH THE
HIGH BUILDING INTO THE REGION. HOWEVER...CONVECTIVE TEMPS WILL BE
IN THE TEENS UNTIL LATE AFTERNOON...WHICH COULD LEAD TO
REDEVELOPMENT WITHIN CLEARING AREAS. DID DELAY THE CLEARING...BUT
REMAINED OPTIMISTIC THAT MOST AREAS WILL CLEAR THIS AFTERNOON.
ALSO...CONSIDERING CURRENT CONDITIONS...MENTIONED FLURRIES WITHIN
EXPECTED CLOUDY AREAS.
MIN TEMPS TONIGHT VERY DEPENDENT ON WHETHER OR NOT WE GET RID OF
THE CLOUDS TODAY. IF WE DO CLEAR...THERE WILL LIKELY WILL BE A
QUICK DROP THIS EVENING BEFORE RETURN FLOW KICKS IN AND TEMPS
BECOME STEADY AFTER MIDNIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
FRIDAY NIGHT-SATURDAY NIGHT...HIGH PRESSURE MOVING THROUGH SHOULD
LEAD TO DRY WEATHER. NOT SURE ABOUT CLOUD COVER (CONSIDERING
CURRENT CONDITIONS FOLLOWING A SHORTWAVE). CURRENT THOUGHT IS THAT
SINCE THE FRIDAY SHORTWAVE WILL TRACK FURTHER NORTH THAN THE
CURRENT SYSTEM...SHOULD BE LESS CLOUDS. ALSO...ANTICIPATE A WARMER
AIRMASS.
SUNDAY-WEDNESDAY...DETERMINISTIC MODEL RUNS CONTINUE TO SUGGEST A
MORE ACTIVE PATTERN TAKING SHAPE NEXT WEEK AS AN UPPER WAVE
CURRENTLY ACROSS ALASKA DIVES SOUTHWARD INTO THE WESTERN CONUS
DURING THE FIRST HALF OF NEXT WEEK...WITH ZONAL FLOW TRANSITIONING
TO SOUTHWEST FLOW ALOFT DOWNSTREAM ACROSS THE PLAINS. 00Z MODELS
SUGGEST THE POTENTIAL FOR SOME LIGHT SNOW WITH WARM ADVECTION LATER
SUNDAY INTO MONDAY. BEYOND THIS POINT...CONFIDENCE REGARDING ANY
PARTICULAR DETAILS IS VERY LOW...WITH SIGNIFICANT DIFFERENCES AMONG
MODELS IN HANDLING THE UPPER LONGWAVE TROUGH AND TIMING/PLACEMENT
OF EMBEDDED SHORTWAVE TROUGHS. THE LOW TO MID-LEVEL BAROCLINIC ZONE
WILL REMAIN POSITIONED ACROSS THE NORTHERN PLAINS THROUGH MID-WEEK
BEFORE ADVANCING SOUTHWARD. ANY WAVE EJECTING OUT OF THE BROADER
TROUGH TO THE WEST ALONG THIS BAROCLINIC ZONE WILL NEED TO BE
WATCHED FOR SFC CYCLONE DEVELOPMENT...WITH THE 00Z ECMWF INDICATING
A MORE SIGNIFICANT WAVE FOR THE MIDDLE OF THE WEEK. GIVEN THE VARIED
MODEL SOLUTIONS...CONTINUED WITH BROADBRUSHED SLIGHT/CHANCE POPS
THROUGH MUCH OF THE PERIOD. TEMPS THROUGH MID-WEEK LOOK TO BE
SEASONABLE BEFORE COLDER AIR ARRIVES LATE IN THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1148 PM CST WED NOV 27 2013
MVFR CIGS CONTINUE TO REMAIN WEST OF THE RED RIVER VALLEY AND
CONTINUE TO MOVE SOUTH FROM WEST AND CENTRAL ND. WILL GENERALLY KEEP
VFR CIGS ACROSS THE AREA EXCEPT FOR THE EAST/NORTHEAST ZONES. LIGHT
SNOW SHOULD LOWER CIGS AND VISIBILITIES IN THE NORTHEAST ZONES. LOW
LEVEL RH GETS TO BE A THIN LAYER BY THU AFTERNOON. WILL SCATTER
CLOUDS OUT AROUND THE NOON HOUR.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...TG
LONG TERM...TG/MAKOWSKI
AVIATION...HOPPES
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1236 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 1236 AM CST THU NOV 28 2013
STRATUS CLOUDS COVERED ALL BUT THE EXTREME SOUTHWESTERN CORNER OF
THE STATE...AND THE TREND IN SATELLITE LOOP INDICATES THE SOUTHWEST
CORNER SHOULD SOON BE CLOUDY. THE LOW PRESSURE CENTER ASSOCIATED
WITH THE COLD FRONT THAT MOVED THROUGH THE STATE WEDNESDAY WAS WELL
TO THE SOUTHEAST...FROM MINNESOTA/IOWA TO SOUTHERN NEBRASKA AND
NORTHWEST WINDS CONTINUED ACROSS NORTH DAKOTA. THE ARCTIC HIGH WAS
CENTERED OVER NORTHERN MANITOBA WITH ITS AXIS EXTENDING
SOUTHWESTWARD ACROSS SOUTHERN SASKATCHEWAN AND INTO THE
MONTANA/NORTH DAKOTA BORDER. SKIES SHOULD REMAIN CLOUDY FOR THE REST
OF THE NIGHTTIME HOURS...BUT THERE IS UNCERTAINTY AS TO
WHEN/IF/WHERE THE LOW CLOUDS WILL SCATTER DURING THE DAYLIGHT HOURS
ON THANKSGIVING DAY.
ONLY ADJUSTMENTS WERE TO THE HOURLY TEMPERATURE/DEWPOINT TRENDS.
OTHERWISE CURRENT FORECAST ON TRACK.
UPDATE ISSUED AT 924 PM CST WED NOV 27 2013
LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS CONTINUE TO SHOW
WESTERN AND CENTRAL NORTH DAKOTA INUNDATED WITH STRATUS. ISOLATED
FLURRIES CONTINUE IN THE NORTH. ONLY ADJUSTMENT WAS TO RAISE
OVERNIGHT TEMPERATURES BETWEEN 3 AND 5 DEGREES DUE TO THE CLOUDS
AND MIXED BOUNDARY LAYER/BRISK WINDS. LATEST NAM AND RAP13 SHOWS
THE STRATUS CONTINUING THROUGH 18Z THURSDAY...AND POSSIBLY INTO
THE AFTERNOON.
UPDATE ISSUED AT 556 PM CST WED NOV 27 2013
MAIN UPDATE THIS EVENING WAS TO INCREASE SKY GRIDS TO 100 PERCENT
OVER MOST OF WESTERN AND CENTRAL NORTH DAKOTA. LATEST FOG/STRATUS
LOOP IN CONJUNCTION WITH THE RAP13 AND HRRR 925MB-H85 RH FIELD...ARE
VERIFYING WELL AND ARE IN GOOD AGREEMENT TONIGHT. THE STRATUS WILL
MAKE IT TO THE SOUTHERN BORDER IN THE NEXT FEW HOURS AS WELL AS
INTO THE JAMES RIVER VALLEY. EXPECT OVERCAST CONDITIONS WITH ISOLATED
FLURRIES TONIGHT INTO MID MORNING THURSDAY BEFORE SKY IMPROVEMENTS
BEGIN. REST OF FORECAST IS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 352 PM CST WED NOV 27 2013
THE TEMPERATURE ROLLER COASTER WILL CONTINUE TONIGHT AND THURSDAY
AS ANOTHER SHOT OF COLD CANADIAN AIR PUSHES SOUTH INTO NORTH
DAKOTA. LOW STRATUS HAS ADVANCED INTO FAR NORTHWEST ND DURING THE
EARLY AFTERNOON...AND WILL CONTINUE A SOUTHWARD PUSH...ACCOMPANIED
BY A FEW FLURRIES. EXPECT ANOTHER NIGHT OF LOWS IN THE SINGLE
DIGITS TO TEENS SOUTHWEST.
ON THANKSGIVING DAY...HIGH PRESSURE WILL DRIFT INTO EASTERN
NORTH DAKOTA ON THURSDAY...SETTING UP ANOTHER NE-SW TEMPERATURE
GRADIENT. HIGHS ARE FORECAST IN THE MID TEENS NEAR THE TURTLE
MOUNTAINS...LOW TO MID 20S NEAR BISMARCK/MANDAN...AND NEAR 30 AT BOWMAN.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 352 PM CST WED NOV 27 2013
POTENTIAL MAJOR WINTER STORM NEXT WEEK.
THE MAIN FOCUS THROUGH THE EXTENDED PERIOD IS ON A POTENTIAL
WINTER STORM THAT MAY IMPACT THE REGION SUNDAY THROUGH THURSDAY.
AT THIS TIME THERE IS A LOT OF UNCERTAINTY AS TO
TIMING...PLACEMENT AND AMOUNTS. MODEL RUNS HAVE SLOWLY COME INTO
BETTER AGREEMENT OVER THE PAST RUN...BUT THERE ARE STILL LARGE
DISCREPANCIES THAT NEED TO BE RESOLVED BEFORE CONFIDENCE CLIMBS
HIGH ENOUGH TO WARRANT ANY THOUGHT OF WINTER WEATHER HEADLINES.
THE 12 UTC HAS THE POLAR AND SUBTROPICAL JETS PHASING TOGETHER LATE
NEXT WEEK AS A VERY POTENT LONGWAVE TROUGH DIGS SOUTH ACROSS THE
MOUNTAIN WEST. THIS WOULD SET UP VERY STRONG CYCLOGENESIS ACROSS
THE PLAINS. THE ECMWF IS STRONGER AND DEEPER WITH THIS TROUGH AND
CYCLOGENESIS AND THEREFORE FURTHER SOUTH AND SLIGHTLY SLOWER THAN
THE GFS. THE 12 UTC GFS MAINTAINS SPLIT FLOW UNTIL THE VERY END OF
NEXT WEEK AND DEVELOPS MORE OF A PROGRESSIVE OPEN WAVE. THIS WOULD
TEND TO FAVOR A QUICKER AND FURTHER NORTH SOLUTION.
ONE THING THAT IS MORE CERTAIN IS THE INTRUSION OF COLD AIR. A
VERY COLD AIRMASS IS SETTING UP ACROSS EASTERN SIBERIA AND IS
PROGGED TO ENTER EASTERN ALASKA AND FROM THERE MAKE A BEELINE
TOWARD THE CENTRAL CONTINENTAL USA. THIS COULD POTENTIALLY BE THE
COLDEST AIR WE HAVE SEEN YET WITH 850MB TEMPS AROUND -25.
UNTIL LATE SUNDAY TEMPERATURES SHOULD BE MILD AND AND PRECIP
CHANCES MINIMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1236 AM CST THU NOV 28 2013
LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW MVFR CIGS
ACROSS NEARLY ALL OF NORTH DAKOTA EARLY THIS MORNING. EXPECT ALL
AERODROMES TO REMAIN MVFR THROUGH SUNRISE. CIGS SHOULD BEGIN TO
IMPROVE TO VFR DURING THE LATE AFTERNOON OR EARLY EVENING HOURS ON
THURSDAY. THERE IS MUCH UNCERTAINTY FOR WHEN/IF/TIMING OF MVFR
CLOUDS SCATTERING OUT DURING THE DAYLIGHT HOURS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...RK
LONG TERM...AJ
AVIATION...JV
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
331 AM CST THU NOV 28 2013
.SHORT TERM...TODAY THROUGH SATURDAY
AN EXTENSIVE STRATUS DECK OVER THE REGION IS KEEPING TEMPERATURES
RELATIVELY MILD WITH CURRENT READINGS IN THE MID 20S. BASED ON THE
PAST FEW RUNS OF THE RUC...IT SEEMS UNLIKELY THIS STRATUS DECK
WILL DISSIPATE ANYTIME SOON. WOULD NOT BE TOO SURPRISED IF THESE
CLOUDS HANG AROUND THROUGH THIS AFTERNOON BEFORE DRIER AIR AT 925
MB MOVES IN FROM THE SOUTHWEST. OF COURSE THESE CLOUDS WILL MAKE
FORECASTING HIGH TEMPERATURES RATHER DIFFICULT. HAVE RELIED UPON
THE RUC MODEL WHICH SHOWS A SLIGHT COOL DOWN AROUND SUNRISE...THEN
A SLIGHT INCREASE BY 21Z.
HIGH PRESSURE SHIFTS EAST OF THE REGION TONIGHT...ALLOWING WAA TO
SPREAD ACROSS THE WESTERN CWA WHERE TEMPERATURES SHOULD BECOME
STEADY OR SLOWLY RISE AFTER MIDNIGHT. ANOTHER WEAK LOW PRESSURE
SYSTEM PASSING ACROSS THE REGION ON FRIDAY WILL BRING WARM
TEMPERATURES BACK INTO THE AREA. TEMPS AT 925/850 MB ARE PROJECTED
TO RANGE AROUND NORMAL...WHICH WHEN COMBINED WITH DECENT MIXING
WINDS SHOULD EQUAL HIGHS IN THE MID 30S...TO THE MID 40S. WOULD
NOT BE TOO SURPRISED IF HIGH TEMPERATURES END UP BEING WARMER.
SLIGHTLY COOLER LOW LEVEL TEMPERATURES ALONG WITH WEAK CAA ON
SATURDAY WILL RESULT IN HIGHS IN THE LOW TO MID 30S.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
LATEST MODEL RUNS CONTINUE TO FORECAST A MAJOR PATTERN SHIFT
DURING THE LONG TERM. HOWEVER THE DETAILS REMAIN SKETCHY AS EACH
MODEL HAS ITS OWN IDEA ON HOW TO HANDLE ENERGY WITHIN THE
DEVELOPING MID LEVEL TROF AND THAT TROFS EVOLUTION THROUGH THE
MIDDLE OF NEXT WEEK. THE ECMWF IS BY FAR THE MOST AGGRESSIVE IN
SETTING UP A BAROCLINIC ZONE ACROSS THE REGION AND CRANKS OUT
COPIOUS AMOUNTS OF PCPN FROM TUESDAY THROUGH THURSDAY. THE GFS IS
MORE PROGRESSIVE AND FEATURES A MORE POSITIVE TILT MID LEVEL TROF
OVER THE WESTERN/CENTRAL CONUS LEADING TO A LESS INTENSE
BAROCLINIC ZONE OVER THE NORTHERN PLAINS. THE LAST COUPLE RUNS OF
THE ECMWF HAVE BEEN CONSISTENTLY SLOWER AND WETTER VS THE GFS.
BUT IT SEEMS OVERLY WET. NONETHELESS WILL BE AN INTERESTING MIDDLE
OF NEXT WEEK WEATHER-WISE WITH A MIXED BAG OF PCPN EXPECTED NO
MATTER WHICH MODEL YOU LIKE. TEMPERATURES ARE EXPECTED TO BE ABOVE
NORMAL FOR THE FIRST PART OF THE PERIOD...BUT THEN TRANSITION
TOWARD NORMAL AS COLDER AIR INVADES FROM CANADA TOWARD MID TO LATE
WEEK.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
MVFR STRATUS /1500FT TO 2500FT AGL CIGS/ IS SPREADING OVER ALL
FOUR TERMINALS. KATY SHOULD SEE THE STRATUS WORKING IN BY 08Z.
CURRENT MODEL DEPICTIONS SUGGEST THE CLOUDS ARE BREAKING UP OR
LIFTING BY AROUND 18Z THURSDAY. THERE COULD ALSO END UP BEING A
FEW SNOW FLURRIES OBSERVED FALLING OUT OF THIS STRATUS FIELD
BEFORE IT`S ALL SAID AND DONE. WINDS WILL BE FROM THE NORTHWEST AT
ALL FOUR TERMINALS THROUGH THURSDAY MORNING BEFORE SURFACE HIGH
PRESSURE BUILDING INTO THE REGION TURNS THEM LIGHT AND VARIABLE
AND THEN EVENTUALLY SOUTHEASTERLY AROUND 5 TO 10 KNOTS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...SD
LONG TERM...TDK
AVIATION...DORN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1134 PM CST WED NOV 27 2013
.UPDATE...
ISSUED AT 712 PM CST WED NOV 27 2013
FRONTOGENETIC BAND FROM NORTHERN MINNESOTA INTO NORTH CENTRAL
WISCONSIN CONTINUES TO PRODUCE EFFICIENT SNOW AMOUNTS WITH DECENT
LIFT IN DENDRITIC SNOW GROWTH ZONE. REPORTS OF 2 TO 4 INCHES
UPSTREAM...AND EVEN THOUGH FORCING IS FORECAST TO WEAKEN AS SYSTEM
ADVECTS EAST...BUMPED UP SNOW ACCUMULATIONS SLIGHTLY MAINLY ALONG
AND NORTH OF HIGHWAY 29 IN PARTS OF NORTH CENTRAL WISCONSIN TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH THANKSGIVING)
ISSUED AT 310 PM CST WED NOV 27 2013
OVERALL A QUIET WEATHER PERIOD THROUGH THE WEEKEND...AFTER SOME
LIGHT SNOW ACROSS THE NORTH TONIGHT.
HAVE BEEN MONITORING SHORTWAVE TROUGH 1 MOVING INTO MINNESOTA
THIS AFTERNOON WITH LIGHT SNOW IN THE 1-2SM VISIBILITY
RANGE...WITH A BIT LOWER FURTHER NORTHWEST ALONG THE MN/CANADA
BORDER. ECHO IS INCREASING IN NW WI...BUT THE PRECIPITATION IS
WORKING ON SATURATION AND NOT MAKING IT TO THE SURFACE. THE UPPER
TROPOSPHERIC SHORTWAVE TROUGH IS LOCATED IN NWRN MN AT 20Z PER
GOES WATER VAPOR IMAGERY...WITH SHORTWAVE TROUGH 2 ON ITS HEALS
JUST NORTHWEST OF LAKE WINNIPEG. MORNING RAOB AT KMPX WAS DEEPLY
DRY BUT THE FORCING WITH THE SHORTWAVE TROUGH IS WORKING PRETTY
RAPIDLY TO SATURATE THE COLUMN AND PRODUCE SNOW....ON THE ORDER OF
A COUPLE HOURS. PER THE LATEST RAP...THIS FORCING IS A
CONTRIBUTION FROM WARM ADVECTION IN THE LOW LEVELS / AND 700MB
FRONTOGENESIS/ AND MID-UPPER LEVEL QG CONVERGENCE.
THE FIRST SHORTWAVE WILL TRACK TOWARD THE NORTHERN FORECAST AREA THIS
AFTERNOON AND ARRIVE AROUND 6-7 PM IN CLARK AND TAYLOR COUNTIES
PER RAP FORECASTS AND TRACKING. THIS FIRST SHORTWAVE TROUGH
WEAKENS AS IT MOVES IN PER THE CONSENSUS MODEL GUIDANCE AS THE
SECOND WAVE INTENSIFIES AND DEEPENS. HOWEVER...THERE IS GUIDANCE
/HRRR/ SOLUTIONS DIMINISHING THE WEATHER AS IT MOVES SOUTHEAST
AND DRY AIR IN PLACE WILL DOMINATE. WITH CONSENSUS FORCING SWIPING
A BAND OF SNOW IN THE EVENING AND CURRENT CONDITIONS...HAVE
FORECAST THE SNOW TO MOVE IN DURING THE EVENING AND ACCUMULATE...MAINLY
I-94 AND NORTH. THIS IS NOT A BIG CHANGE TO ONGOING FORECAST..BUT
HIGHER CONFIDENCE. WILL LIKELY HIT THIS A BIT IN THE SOCIAL MEDIA
AND SPECIAL WEATHER STATEMENTS WITH MORE TRAVEL THIS EVENING
HAPPENING.
SOME DIFFICULTY IN TRYING TO FIGURE OUT THE REMAINDER OF THE
NIGHT AFTER MIDNIGHT...AHEAD OF THE SECOND SHORT WAVE TROUGH. IT
APPEARS THE FRONTOGENESIS NEAR 700MB WILL BE STRONGER THAN THE
FIRST SHORTWAVE AND WITH THE UPPER QG FORCING MAINLY OVER NRN WI
/MODEL CONSENSUS/...SNOW SEEMS TO BE A GIVEN. BUT AS SHORTWAVE
TROUGH 2 DEEPENS...THE FORCING SHIFTS INTO NORTHERN WI AND MAY
SPREAD ITS SNOW NORTH OF TAYLOR COUNTY. FEEL FAIRLY CONFIDENT SNOW
WILL OCCUR OVERNIGHT...BUT HAVE DECIDED TO MOVE IT NORTH WITH TIME
AND LEAVE FLURRIES SOUTH TO I-94. THE SNOW RATIOS COULD BE QUITE
HIGH WITH THIS SNOW WITH MOST OF THE SATURATED COLUMN IN THE
DENDRITE GROWTH ZONE -12 TO -18C...THUS LOW QPF COULD PRODUCE AN
INCH PRETTY EASY.
MAINLY FLURRIES SHOULD REMAIN DURING THE EARLY MORNING THURSDAY WITH
ROADS CLEANING UP FOR TRAVEL. SUN IS EXPECTED BY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 PM CST WED NOV 27 2013
A PERIOD OF QUIET WEATHER WITH SOME MODERATION IN TEMPERATURES
BEGINNING FRIDAY...BUT A COLD START THAT MORNING UNDER HIGH
PRESSURE AND CLEAR SKIES. IF A BIT MORE SNOW FALLS IN TAYLOR
COUNTY TONIGHT ACROSS TAYLOR COUNTY...FRIDAY MORNING COULD BE NEAR
ZERO.
NEXT WEATHER SYSTEM SHIFTS ACROSS NORTHERN GREAT LAKES FRIDAY
NIGHT AND SATURDAY WITH THE MORE FAVORABLE FORCING NORTH OF THE
AREA. MAYBE SOME CLOUDS AND FLURRIES IN TAYLOR COUNTY BUT HAVE
KEPT DRY FORECAST INTACT.
SUNDAY THROUGH WEDNESDAY...LOW CONFIDENCE IN THIS PERIOD AS THE
MODEL GUIDANCE HAS DIFFERENT EVOLUTIONS AND TIMING TO THE MAJOR
READJUSTMENT OF THE LARGE SCALE PATTERN OVER NORTH AMERICA. MAJOR
TROUGH AND COLD POOL OF AIR INVADE THE WESTERN CONUS WITH AN
ASTOUNDING -3.5 TO -4 STANDARD DEVIATION BELOW NORMAL 850 MB TEMP
IN THE WESTERN CONUS. BECAUSE OF THE SPREAD IN THE MODELS AND HOW
ENERGY EJECTS OUT OF THE TROUGH...THE FORECAST HAS SMALL
PRECIPITATION CHANCES MONDAY TO WEDNESDAY. THIS COULD BE A DRY
PERIOD SHOULD THE 27.12Z ECMWF SOLUTION OCCUR...WHICH THE 27.12Z
GFS TRENDED TOWARD...WITH MORE WEATHER LATER IN THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY MORNING)
ISSUED AT 1134 PM CST WED NOV 27 2013
MID LEVEL FRONTOGENETIC BAND MOVING ACROSS CENTRAL WISCONSIN IS ONLY
AVIATION IMPACT TONIGHT BUT THAT FEATURE IS QUICKLY PUSHING OFF TO
THE EAST. MEANWHILE NEXT SHORT WAVE WILL BRING A COLD FRONT INTO THE
AREA EARLY THANKSGIVING MORNING AND SHALLOW COLD AIR ADVECTION
THROUGH MUCH OF THE DAY. EXTENSIVE STRATUS FIELD UPSTREAM SUGGESTS
IDEA OF MORE CLOUDS IS ON TRACK WITH INVERSION SETTING UP. DRY
AIRMASS ALOFT BUT IT WILL TAKE SOME TIME TO MIX OUT STRATUS FIELD
LOCKED BELOW.
GENERALLY CONDITIONS WILL REMAIN VFR BUT COULD SEE SOME MVFR
CEILINGS AT TIME...ESPECIALLY NORTH OF INTERSTATE 90 THURSDAY
MORNING. WILL BE OPTIMISTIC THAT CEILINGS WILL BREAK UP HEADING INTO
THURSDAY EVENING AS RIDGE BUILDS IN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE........SHEA
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...SHEA
AREA FORECAST DISCUSSION
NWS ALBANY NY
631 AM EST THU NOV 28 2013
.SYNOPSIS...
LOW PRESSURE WILL CONTINUE TO DEEPEN AND INTENSIFY AS IT MOVES
FURTHER NORTHEAST INTO THE CANADIAN MARITIMES...AS HIGH PRESSURE
WILL ATTEMPT TO BUILD IN FROM THE SOUTHEAST. BLUSTERY AND COLD
CONDITIONS ARE EXPECTED FOR THANKSGIVING TODAY WITH SOME LAKE
EFFECT SNOW SHOWERS WEST OF THE GREATER CAPITAL REGION. A WEAK
DISTURBANCE WILL BRING SOME LAKE EFFECT SNOW SHOWERS AND FLURRIES
TONIGHT INTO EARLY FRIDAY MAINLY WEST OF THE HUDSON RIVER
VALLEY...BEFORE HIGH PRESSURE BUILDS IN LATE FRIDAY INTO THE FIRST
HALF OF THE WEEKEND WITH DRY WEATHER AND BELOW NORMAL TEMPERATURES
TO CLOSE NOVEMBER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM EST...HAPPY THANKSGIVING EVERYONE ! BLUSTERY AND COLD
CONDITIONS GREET ERN NY AND WRN NEW ENGLAND THIS MORNING...AS THE
UPPER TROUGH AXIS TO THE STRONG STORM SYSTEM YESTERDAY HAS CROSSED
THE REGION. THE CYCLONE IS NOW DEEPENING AND INTENSIFYING OVER
LABRADOR /980 HPA/. SOME GUSTY WINDS ARE IMPACTING PARTS OF THE REGION
WITH THE STRONG SFC PRESSURE GRADIENT BETWEEN THE DEPARTING
CYCLONE...AND HIGH PRESSURE OVER THE LOWER MS RIVER
VALLEY/SOUTHEAST. KALB HAD A PEAK WIND GUST OF 39 KTS /45 MPH/
BTWN 1-2 AM AND AT 5 AM. THE CORE OF THE STRONGEST WINDS AT H850 OF
40-50 KTS WILL BE OVER THE ERN HALF OF THE FCST AREA PRIOR TO 12Z.
SOME GUSTS OF 30-45 MPH WILL BE POSSIBLE ESPECIALLY PRIOR TO
NOON...AS THE SFC PRESSURE GRADIENT STARTS TO WEAKEN THEREAFTER.
THE STRONGEST GUSTS WILL BE DUE TO THE FUNNELING EFFECT DOWN THE
MOHAWK RIVER VALLEY.
THE CYCLONIC FLOW WILL CONTINUE WITH H850 TEMPS FALLING TO -18C TO
-13C FROM NORTHWEST TO SOUTHEAST OVER THE FCST AREA. IN THE W/NW
SOME MULTIBANDS OF LAKE EFFECT WILL CONTINUE TO BE POSSIBLE. THE
LATEST HRRR SHOWS A WEAKENING OF THE ACTIVITY AROUND 12Z. THE CURRENT
RADAR SHOWS SEVERAL NARROW MULTIBANDS OFF LAKE ONTARIO IMPACTING
THE WRN DACKS...W-CNTRL MOHAWK...AND NRN CATSKILLS. THESE BANDS
SEEM TO BE ENDURING SOME SHEAR AND DRY AIR INTRUDING. POPS WERE
ADJUSTED FOR MORE SNOW SHOWERS OVER THE NRN AND ERN CATSKILLS.
NONETHELESS...LOCALLY A BURST OF WIND DRIVEN SNOW IS POSSIBLE
ESPECIALLY ACROSS THE WRN DACKS...W-CNTRL MOHAWK VALLEY...AND THE
SRN GREENS/BERKS...DUE TO THE W/NW UPSLOPE COMPONENT. THE LAKE
EFFECT ADVISORY FOR SRN HERKIMER WILL CONTINUE...IT GOES ALL THE
WAY TO 7 AM TOMORROW. THE ACTIVITY MAY SLIP SOUTH OF THE ADVISORY
AREA LATER TODAY BASED ON THE HRRR...BUT THE LOCAL HIRES WRF SHOWS
A COUPLE OF BANDS IN THE 300 DEG TRAJECTORY BOUNDARY LAYER
FLOW...AND ONE DOES GO THROUGH SRN HERKIMER...MONTGOMERY AND WRN
FULTON COUNTIES INTO THE PM. BOTH FORMS OF HIGH RESOLUTION
GUIDANCE SHOWS THE BANDS WEAKENING IN THE AFTERNOON...UNTIL A
SHORT-WAVE ARRIVES TONIGHT FROM THE GREAT LAKES REGION.
COLD...WINDY...AND PARTLY CLOUDY CONDITIONS WILL PERSIST TODAY FOR A
LARGE PORTION OF THE AREA WITH HIGH TEMPS ABOUT 15 DEGREES BELOW
NORMAL. EXPECT HIGHS IN THE TEENS AND L20S OVER THE SRN
DACKS...SRN GREENS...AND ERN CATSKILLS. MID AND U20S WILL BE
COMMON ELSEWHERE...EXCEPT FOR A FEW L30S IN THE MID HUDSON
VALLEY...SRN TACONICS...AND LITCHFIELD CTY CT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
TONIGHT...THE AFOREMENTIONED IMPULSE IN THE CYCLONIC FLOW WILL MOVE
ACROSS THE REGION WITH SOME LAKE ENHANCED SNOW SHOWERS AND
FLURRIES. THE BOUNDARY LAYER FLOW SHOULD BACK INITIALLY FOR A
270-280 DEG TRAJECTORY FOR PERHAPS THE CNTRL PORTION OF HERKIMER
AND SW HAMILTON COS TO GET A LITTLE SNOW...BEFORE VEERING AGAIN INTO
THE WRN-CNTRL MOHAWK VALLEY AND NRN CATSKILLS. ANOTHER FEW INCHES
OF SNOW WILL BE POSSIBLE IN THESE LOCATIONS...AND A 3-6" TALLY FOR
THE ADVISORY AREA LOOKS FINE. CLOUDS WILL INCREASE FOR THE BULK OF
THE REGION WITH PERHAPS SOME FLURRIES FROM THE CAPITAL REGION
EASTWARD. THE MID LEVEL VORT MAX/SHORT-WAVE SHOULD MOVE DOWNSTREAM
BY FRI MORNING WITH THE INVERSION HEIGHTS STARTING TO LOWER TO
SQUASH THE LAKE EFFECT ACTIVITY. A COLD NIGHT IS EXPECTED WITH
MAINLY TEENS FOR LOWS FOR THE REGION...EXCEPT SOME SINGLE DIGITS
FOR THE SRN ADIRONDACK REGION....AND SRN GREENS.
FRIDAY...THE BIG SHOPPING DAY LOOKS MAINLY DRY WITH THE LAKE EFFECT
SNOW SHOWERS AND FLURRIES DWINDLING WITH A STRONG SFC ANTICYCLONE
RIDGING IN FROM SE ONTARIO...AND THE ERN GREAT LAKES REGION. THE
BEST CHC OF A STRAY SNOW SHOWER WILL BE OVER THE W-CNTRL MOHAWK
RIVER VALLEY...AND NRN CATSKILLS. H850 TEMPS WILL STILL BE A
LITTLE BELOW NORMAL WITH -12C TO -15C READINGS. MAX TEMPS MAY BE A
SMIDGE WARMER THAN THANKSGIVING WITH HIGHS IN THE U20S TO L30S IN
THE VALLEYS /EXCEPT THE MID HUDSON RIVER VALLEY WHERE A FEW M30S
WILL BE POSSIBLE/...AND MAINLY LOWER TO M20S OVER THE HIGH PEAKS.
FRIDAY NIGHT...A VERY COLD NIGHT WILL BE ON TAP...AS THE SFC HIGH
STRENGTHENS TO 1043 HPA OVER ERN NY ON THE NAM40. MOSTLY
CLEAR/CLEAR SKIES WITH LIGHT TO CALM WINDS WILL YIELD IDEAL
RADIATIONAL COOLING CONDITIONS WITH LOWS FORECASTED CLOSER TO THE
NAM MOS GUIDANCE. LOWS 5 ABOVE TO 5 BELOW ZERO OVER THE LAKE
GEORGE REGION...AND SRN DACKS. SINGLE DIGITS IN THE MOHAWK RIVER
VALLEY...NRN CATSKILLS...HELDERBERGS...SRN VT...N-CNTRL BERKS...AND
NRN SARATOGA REGION...LOWER TEENS IN THE CAPITAL
DISTRICT..TACONICS...SRN BERKS...MID HUDSON VALLEY...AND NW CT.
SATURDAY-SATURDAY NIGHT...DRY WEATHER WILL START THE WEEKEND WITH
TEMPS STILL RUNNING BELOW NORMAL BY 10-15 DEGS. THE SFC HIGH MOVES
DOWN STREAM OVER NRN NEW ENGLAND AND THE GULF OF MAINE. A LIGHT
S/SE BREEZE BEGINS LATE IN THE DAY. MOSTLY SUNNY SKIES EARLY ON
WILL GIVE WAY TO INCREASE MID AND HIGH CLOUDS IN THE WARM
ADVECTION REGIME. A CLIPPER LOW WILL BE APPROACHING FROM THE NRN
GREAT LAKES REGION...AND S-CNTRL ONTARIO. THE TIMING IS VARIABLE
ON THE GUIDANCE...AND SLIGHT CHC OF SNOW SHOWERS WAS PLACED IN THE
GRIDS AFTER MIDNIGHT. LOWS SATURDAY WILL BE MUCH WARMER THAN THE
PREVIOUS NIGHTS WITH TEENS TO THE NORTH OF THE MOHAWK RIVER
VALLEY/CAPITAL REGION...AND LOWER TO M20S TO THE SOUTH.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MUCH OF THE LONG TERM PERIOD IS EXPECTED TO BE DRY WITH THE MAIN
FEATURE FOR EARLY NEXT WEEK BEING A COASTAL LOW WHICH WOULD
POTENTIALLY IMPACT THE FA IN THE TUESDAY TO TUESDAY NIGHT TIME FRAME.
SUNDAY AND SUNDAY NIGHT...A CLIPPER TYPE SYSTEM WITH LIMITED
MOISTURE IS EXPECTED TO IMPACT THE FA AS IT TRACKS ACRS SRN CANADA
AND NRN NEW ENGLAND. HIGHS ON SUNDAY ARE EXPECTED TO RANGE FROM THE
LOWER 30S NORTHWEST TO MID 40S SOUTHEAST WITH LOWS SUNDAY NIGHT
GENERALLY IN THE 20S TO AROUND 30.
MONDAY AND MONDAY NIGHT...LOOK TO BE DRY AS HIGH PRESSURE BRIEFLY
BUILDS BACK INTO THE FA. HIGHS ARE EXPECTED TO BE IN THE 30S TO
AROUND 40 WITH SOME UPPER 20S ACROSS THE WESTERN ADIRONDACKS. LOWS
ARE EXPECTED TO BE IN THE MID TEENS TO UPPER 20S.
TUESDAY AND TUESDAY NIGHT...A COASTAL LOW MAY IMPACT THE FA AS IT
WORKS NORTHWARD UP THE EASTERN SEABOARD TUESDAY AND INTO THE GULF OF
MAINE BY LATE TUESDAY NIGHT. TOO FAR OUT TO GET VERY SPECIFIC AT THIS
POINT IN TIME...BUT WILL INCLUDE CHANCE POPS IN THE FORECAST FOR
NOW. EXPECT HIGHS ON TUESDAY IN THE UPPER 20S TO UPPER 30S WITH LOWS
TUESDAY NIGHT IN THE MID TEENS TO MID 20S.
WEDNESDAY...AT THIS TIME LOOKS TO BE A DRY DAY AS COASTAL SYSTEM
DEPARTS EAST OF THE CANADIAN MARITIMES AND A RIDGE OF HIGH PRESSURE
BUILDS SOUTHEAST FROM NORTH OF THE UPPER GREAT LAKES. EXPECT HIGHS
ON WEDNESDAY TO BE IN THE MID 20S TO UPPER 30S.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH THE
END OF THE TAF PERIOD ENDING AT 12Z FRI. SKIES WILL GENERALLY BE
SCT025-040 SCT100 TODAY EXCEPT FOR BRIEFLY OVC025 AT KPSF. SKIES
WILL BECOME SKC THIS EVENING.
THE WEST-NORTHWEST WINDS WILL REMAIN STRONG AS A STRONG PRESSURE
GRADIENT REMAINS ACRS THE REGION. WIND GUSTS WILL INCREASE TO
OVER 30 KTS AT TIMES. THE WINDS WILL GRADUALLY DIMINISH THU EVENING
BECOMING LIGHT AND VARIABLE AFTER DARK.
OUTLOOK...
FRIDAY TO SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
SUNDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...SHSN.
SUNDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...SHSN.
&&
.HYDROLOGY...
THE RIVERS HAVE CRESTED...AND FLOWS ARE STARTING TO DECREASE WITH
THE COLDER TEMPS. THE TREND THE NEXT 5 DAYS ARE FOR FLOWS TO
DECREASE IN THE COLD AND DRY AIR MASS INTO THE HOLIDAY WEEKEND.
ANY PRECIP WILL BE IN THE FORM OF SNOW SHOWERS PREDOMINANTLY WEST
OF THE HUDSON RIVER VALLEY TODAY INTO FRIDAY. A CLIPPER LOW MAY
BRING SOME SCT SNOW SHOWERS TO THE REGION TO CLOSE THE WEEKEND
WITH VERY LIGHT QPF. MOST LOCATIONS OUTSIDE OF THE FAVORED LAKE
EFFECT AREAS ARE NOT EXPECTED TO RECEIVE A TENTH OF AN INCH OF
LIQUID EQUIVALENT THE NEXT 5 DAYS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST FRIDAY FOR NYZ038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...11
AVIATION...11
HYDROLOGY...JPV/WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
609 AM EST THU NOV 28 2013
.SYNOPSIS...
LOW PRESSURE WILL CONTINUE TO DEEPEN AND INTENSIFY AS IT MOVES
FURTHER NORTHEAST INTO THE CANADIAN MARITIMES...AS HIGH PRESSURE
WILL ATTEMPT TO BUILD IN FROM THE SOUTHEAST. BLUSTERY AND COLD
CONDITIONS ARE EXPECTED FOR THANKSGIVING TODAY WITH SOME LAKE
EFFECT SNOW SHOWERS WEST OF THE GREATER CAPITAL REGION. A WEAK
DISTURBANCE WILL BRING SOME LAKE EFFECT SNOW SHOWERS AND FLURRIES
TONIGHT INTO EARLY FRIDAY MAINLY WEST OF THE HUDSON RIVER
VALLEY...BEFORE HIGH PRESSURE BUILDS IN LATE FRIDAY INTO THE FIRST
HALF OF THE WEEKEND WITH DRY WEATHER AND BELOW NORMAL TEMPERATURES
TO CLOSE NOVEMBER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM EST...HAPPY THANKSGIVING EVERYONE ! BLUSTERY AND COLD
CONDITIONS GREET ERN NY AND WRN NEW ENGLAND THIS MORNING...AS THE
UPPER TROUGH AXIS TO THE STRONG STORM SYSTEM YESTERDAY HAS CROSSED
THE REGION. THE CYCLONE IS NOW DEEPENING AND INTENSIFYING OVER NEW
BRUNSWICK /984 HPA/. SOME GUSTY WINDS ARE IMPACTING PARTS OF THE
REGION WITH THE STRONG SFC PRESSURE GRADIENT BETWEEN THE DEPARTING
CYCLONE...AND HIGH PRESSURE OVER THE LOWER MS RIVER
VALLEY/SOUTHEAST. KALB HAD A PEAK WIND GUST OF 39 KTS /45 MPH/
BTWN 1-2 AM. THE CORE OF THE STRONGEST WINDS AT H850 OF 40-50 KTS
WILL BE OVER THE ERN HALF OF THE FCST AREA PRIOR TO 12Z. SOME
GUSTS OF 30-40 MPH WILL BE POSSIBLE ESPECIALLY PRIOR TO NOON...AS
THE SFC PRESSURE GRADIENT STARTS TO WEAKEN THEREAFTER.
THE CYCLONIC FLOW WILL CONTINUE WITH H850 TEMPS FALLING TO -18C TO
-13C FROM NORTHWEST TO SOUTHEAST OVER THE FCST AREA. IN THE W/NW
SOME MULTIBANDS OF LAKE EFFECT WILL CONTINUE TO BE POSSIBLE. THE
LATEST HRRR SHOWS A WEAKENING OF THE ACTIVITY TOWARDS 12Z. THE
CURRENT RADAR SHOWS SEVERAL NARROW MULTIBANDS OFF LAKE ONTARIO
IMPACTING THE WRN DACKS...W-CNTRL MOHAWK...AND NRN CATSKILLS.
THESE BANDS SEEM TO BE ENDURING SOME SHEAR AND DRY AIR INTRUDING.
NONETHELESS...LOCALLY A BURST OF WIND DRIVEN SNOW IS POSSIBLE
ESPECIALLY ACROSS THE WRN DACKS...W-CNTRL MOHAWK VALLEY...AND THE
SRN GREENS/BERKS...DUE TO THE W/NW UPSLOPE COMPONENT. THE LAKE
EFFECT ADVISORY FOR SRN HERKIMER WILL CONTINUE...IT GOES ALL THE
WAY TO 7 AM TOMORROW. THE ACTIVITY MAY SLIP SOUTH OF THE ADVISORY
AREA LATER TODAY BASED ON THE HRRR...BUT THE LOCAL HIRES WRF SHOWS
A COUPLE OF BANDS IN THE 300 DEG TRAJECTORY BOUNDARY LAYER
FLOW...AND ONE DOES GO THROUGH SRN HERKIMER...MONTGOMERY AND WRN
FULTON COUNTIES INTO THE PM. BOTH FORMS OF HIGH RESOLUTION
GUIDANCE SHOWS THE BANDS WEAKENING IN THE AFTERNOON...UNTIL A
SHORT-WAVE ARRIVES TONIGHT FROM THE GREAT LAKES REGION.
COLD...WINDY...AND PARTLY CLOUDY CONDITIONS WILL PERSIST TODAY FOR A
LARGE PORTION OF THE AREA WITH HIGH TEMPS ABOUT 15 DEGREES BELOW
NORMAL. EXPECT HIGHS IN THE TEENS AND L20S OVER THE SRN
DACKS...SRN GREENS...AND ERN CATSKILLS. MID AND U20S WILL BE
COMMON ELSEWHERE...EXCEPT FOR A FEW L30S IN THE MID HUDSON
VALLEY...SRN TACONICS...AND LITCHFIELD CTY CT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
TONIGHT...THE AFOREMENTIONED IMPULSE IN THE CYCLONIC FLOW WILL MOVE
ACROSS THE REGION WITH SOME LAKE ENHANCED SNOW SHOWERS AND
FLURRIES. THE BOUNDARY LAYER FLOW SHOULD BACK INITIALLY FOR A
270-280 DEG TRAJECTORY FOR PERHAPS THE CNTRL PORTION OF HERKIMER
AND SW HAMILTON COS TO GET A LITTLE SNOW...BEFORE VEERING AGAIN INTO
THE WRN-CNTRL MOHAWK VALLEY AND NRN CATSKILLS. ANOTHER FEW INCHES
OF SNOW WILL BE POSSIBLE IN THESE LOCATIONS...AND A 3-6" TALLY FOR
THE ADVISORY AREA LOOKS FINE. CLOUDS WILL INCREASE FOR THE BULK OF
THE REGION WITH PERHAPS SOME FLURRIES FROM THE CAPITAL REGION
EASTWARD. THE MID LEVEL VORT MAX/SHORT-WAVE SHOULD MOVE DOWNSTREAM
BY FRI MORNING WITH THE INVERSION HEIGHTS STARTING TO LOWER TO
SQUASH THE LAKE EFFECT ACTIVITY. A COLD NIGHT IS EXPECTED WITH
MAINLY TEENS FOR LOWS FOR THE REGION...EXCEPT SOME SINGLE DIGITS
FOR THE SRN ADIRONDACK REGION....AND SRN GREENS.
FRIDAY...THE BIG SHOPPING DAY LOOKS MAINLY DRY WITH THE LAKE EFFECT
SNOW SHOWERS AND FLURRIES DWINDLING WITH A STRONG SFC ANTICYCLONE
RIDGING IN FROM SE ONTARIO...AND THE ERN GREAT LAKES REGION. THE
BEST CHC OF A STRAY SNOW SHOWER WILL BE OVER THE W-CNTRL MOHAWK
RIVER VALLEY...AND NRN CATSKILLS. H850 TEMPS WILL STILL BE A
LITTLE BELOW NORMAL WITH -12C TO -15C READINGS. MAX TEMPS MAY BE A
SMIDGE WARMER THAN THANKSGIVING WITH HIGHS IN THE U20S TO L30S IN
THE VALLEYS /EXCEPT THE MID HUDSON RIVER VALLEY WHERE A FEW M30S
WILL BE POSSIBLE/...AND MAINLY LOWER TO M20S OVER THE HIGH PEAKS.
FRIDAY NIGHT...A VERY COLD NIGHT WILL BE ON TAP...AS THE SFC HIGH
STRENGTHENS TO 1043 HPA OVER ERN NY ON THE NAM40. MOSTLY
CLEAR/CLEAR SKIES WITH LIGHT TO CALM WINDS WILL YIELD IDEAL
RADIATIONAL COOLING CONDITIONS WITH LOWS FORECASTED CLOSER TO THE
NAM MOS GUIDANCE. LOWS 5 ABOVE TO 5 BELOW ZERO OVER THE LAKE
GEORGE REGION...AND SRN DACKS. SINGLE DIGITS IN THE MOHAWK RIVER
VALLEY...NRN CATSKILLS...HELDERBERGS...SRN VT...N-CNTRL BERKS...AND
NRN SARATOGA REGION...LOWER TEENS IN THE CAPITAL
DISTRICT..TACONICS...SRN BERKS...MID HUDSON VALLEY...AND NW CT.
SATURDAY-SATURDAY NIGHT...DRY WEATHER WILL START THE WEEKEND WITH
TEMPS STILL RUNNING BELOW NORMAL BY 10-15 DEGS. THE SFC HIGH MOVES
DOWN STREAM OVER NRN NEW ENGLAND AND THE GULF OF MAINE. A LIGHT
S/SE BREEZE BEGINS LATE IN THE DAY. MOSTLY SUNNY SKIES EARLY ON
WILL GIVE WAY TO INCREASE MID AND HIGH CLOUDS IN THE WARM
ADVECTION REGIME. A CLIPPER LOW WILL BE APPROACHING FROM THE NRN
GREAT LAKES REGION...AND S-CNTRL ONTARIO. THE TIMING IS VARIABLE
ON THE GUIDANCE...AND SLIGHT CHC OF SNOW SHOWERS WAS PLACED IN THE
GRIDS AFTER MIDNIGHT. LOWS SATURDAY WILL BE MUCH WARMER THAN THE
PREVIOUS NIGHTS WITH TEENS TO THE NORTH OF THE MOHAWK RIVER
VALLEY/CAPITAL REGION...AND LOWER TO M20S TO THE SOUTH.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MUCH OF THE LONG TERM PERIOD IS EXPECTED TO BE DRY WITH THE MAIN
FEATURE FOR EARLY NEXT WEEK BEING A COASTAL LOW WHICH WOULD
POTENTIALLY IMPACT THE FA IN THE TUESDAY TO TUESDAY NIGHT TIME FRAME.
SUNDAY AND SUNDAY NIGHT...A CLIPPER TYPE SYSTEM WITH LIMITED
MOISTURE IS EXPECTED TO IMPACT THE FA AS IT TRACKS ACRS SRN CANADA
AND NRN NEW ENGLAND. HIGHS ON SUNDAY ARE EXPECTED TO RANGE FROM THE
LOWER 30S NORTHWEST TO MID 40S SOUTHEAST WITH LOWS SUNDAY NIGHT
GENERALLY IN THE 20S TO AROUND 30.
MONDAY AND MONDAY NIGHT...LOOK TO BE DRY AS HIGH PRESSURE BRIEFLY
BUILDS BACK INTO THE FA. HIGHS ARE EXPECTED TO BE IN THE 30S TO
AROUND 40 WITH SOME UPPER 20S ACROSS THE WESTERN ADIRONDACKS. LOWS
ARE EXPECTED TO BE IN THE MID TEENS TO UPPER 20S.
TUESDAY AND TUESDAY NIGHT...A COASTAL LOW MAY IMPACT THE FA AS IT
WORKS NORTHWARD UP THE EASTERN SEABOARD TUESDAY AND INTO THE GULF OF
MAINE BY LATE TUESDAY NIGHT. TOO FAR OUT TO GET VERY SPECIFIC AT THIS
POINT IN TIME...BUT WILL INCLUDE CHANCE POPS IN THE FORECAST FOR
NOW. EXPECT HIGHS ON TUESDAY IN THE UPPER 20S TO UPPER 30S WITH LOWS
TUESDAY NIGHT IN THE MID TEENS TO MID 20S.
WEDNESDAY...AT THIS TIME LOOKS TO BE A DRY DAY AS COASTAL SYSTEM
DEPARTS EAST OF THE CANADIAN MARITIMES AND A RIDGE OF HIGH PRESSURE
BUILDS SOUTHEAST FROM NORTH OF THE UPPER GREAT LAKES. EXPECT HIGHS
ON WEDNESDAY TO BE IN THE MID 20S TO UPPER 30S.
&&
.AVIATION /11Z THURSDAY THROUGH MONDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH THE
END OF THE TAF PERIOD ENDING AT 12Z FRI. SKIES WILL GENERALLY BE
SCT025-040 SCT100 TODAY EXCEPT FOR BRIEFLY OVC025 AT KPSF. SKIES
WILL BECOME SKC THIS EVENING.
THE WEST-NORTHWEST WINDS WILL REMAIN STRONG AS A STRONG PRESSURE
GRADIENT REMAINS ACRS THE REGION. WIND GUSTS WILL INCREASE TO
OVER 30 KTS AT TIMES. THE WINDS WILL GRADUALLY DIMINISH THU EVENING
BECOMING LIGHT AND VARIABLE AFTER DARK.
OUTLOOK...
THURSDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
FRIDAY TO SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
SUNDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...SHSN.
SUNDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...SHSN.
&&
.HYDROLOGY...
THE RIVERS HAVE CRESTED...AND FLOWS ARE STARTING TO DECREASE WITH
THE COLDER TEMPS. THE TREND THE NEXT 5 DAYS ARE FOR FLOWS TO
DECREASE IN THE COLD AND DRY AIR MASS INTO THE HOLIDAY WEEKEND.
ANY PRECIP WILL BE IN THE FORM OF SNOW SHOWERS PREDOMINANTLY WEST
OF THE HUDSON RIVER VALLEY TODAY INTO FRIDAY. A CLIPPER LOW MAY
BRING SOME SCT SNOW SHOWERS TO THE REGION TO CLOSE THE WEEKEND
WITH VERY LIGHT QPF. MOST LOCATIONS OUTSIDE OF THE FAVORED LAKE
EFFECT AREAS ARE NOT EXPECTED TO RECEIVE A TENTH OF AN INCH OF
LIQUID EQUIVALENT THE NEXT 5 DAYS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST FRIDAY FOR NYZ038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...11
AVIATION...11
HYDROLOGY...JPV/WASULA
AREA FORECAST DISCUSSION
NWS MIAMI FL
951 AM EST THU NOV 28 2013
.UPDATE...
OUTSIDE OF A FEW MINOR TWEAKS BASED ON THE LATEST OBSERVATIONS
AROUND THE LOCAL AREA...NO MAJOR UPDATES WERE NECESSARY. THE
WINDS OVER LAKE OKEECHOBEE WERE SLIGHTLY HIGHER THAN ORIGINALLY
EXPECTED DUE TO STRONGER WINDS MIXING DOWN OVER THE WARMER LAKE
WATERS...WHICH HAS PROMPTED A SHORT-FUSED ADVISORY. THESE WINDS
SHOULD TREND DOWN THROUGH THE LATE MORNING AND AFTERNOON PERIOD AS
THE GRADIENT RELAXES.
THE MAIN STORY THIS MORNING HAS BEEN THE COOL TEMPERATURES...WHICH
MARKS THE COOLEST MORNING OF THE SEASON FOR SOUTH FLORIDA.
BRIGHTON IN NORTHERN GLADES COUNTY BRIEFLY DROPPED TO 36 DEGREES
...WHICH WAS THE COLDEST RECORDED TEMPERATURE IN OUR LOCAL AREA
TODAY. ELSEWHERE...TEMPERATURES RANGED FROM THE UPPER 30S FROM THE
INTERIOR AREAS (PALMDALE TO IMMOKALEE) TO THE LOWER 50S ALONG THE
COAST IN MIAMI-DADE COUNTY. THE MORNING SOUNDING AT MIAMI
REFLECTED THIS COOL AIR AT THE SURFACE BELOW A STRONG LOW-LEVEL
INVERSION AROUND 1700 FT...THEN TOPPED WITH A SUBSTANTIAL AMOUNT
OF DRY AIR ABOVE 3500 FT (PWAT OF .5"). THE LATEST RUC ANALYSIS
HAS LINED UP WELL WITH THE CURRENT SYNOPTIC PATTERN AND GENERALLY
INDICATES THE COLD AIR ADVECTION COMING TO AN END LATER TODAY AS
THE LOW-LEVEL FLOW QUICKLY SHIFTS TO THE NORTHEAST. AFTERNOON
HIGHS ARE FORECAST TO CLIMB INTO THE LOWER 70S. AG
&&
.PREV DISCUSSION... /ISSUED 645 AM EST THU NOV 28 2013/
AVIATION...VFR WILL PREVAIL. SKIES WILL BE MOSTLY CLEAR AT KAPF
THROUGH THE PERIOD. FOR THE EAST COAST, EXPECT SCT-BKN STRATO CU
TO INCREASE LATER TODAY...AT AROUND 5K FT. BRIEF MVFR CIGS WILL
CONTINUE IN MIAMI-DADE OVER THE NEXT HOUR BUT ARE EXPECTED TO
IMPROVE. MOISTURE LOOKS TOO SHALLOW TO ADD ANY SHOWER MENTION.
WINDS WILL PREVAIL NW AT NEAR 10 KT. GFS/NAM MOS LIKELY BRINGING
WINDS OUT OF THE NE TOO QUICKLY ATLANTIC TERMINALS. HRRR LOOKS TO
HAVE THE RIGHT IDEA, DELAYING NE WINDS UNTIL 18-19Z. /GREGORIA
PREV DISCUSSION... /ISSUED 406 AM EST THU NOV 28 2013/
DISCUSSION...
TEMPERATURES IN THE LOW TO MID 50S ARE SEEN THIS MORNING ALONG
THE EAST COAST WITH MID TO UPPER 40S ACROSS THE INTERIOR WITH
BRISK NORTHERLY WINDS. WINDS SHOULD BEGIN TO VEER MORE TO THE
NORTHEAST THROUGH THE DAY ALLOWING MORE OF A MARITIME INFLUENCE
AND WEAK MOISTURE RETURN ACROSS THE AREA PARTICULARLY FOR THE
EASTERN HALF OF THE AREA. HOWEVER...GENERALLY RAIN FREE WEATHER
SHOULD PREVAIL THROUGH THE DAY.
NORTHEAST FLOW SHOULD THEN PERSIST THROUGH THE WEEKEND AS HIGH
PRESSURE REMAINS CENTERED JUST OFF THE CAROLINA COAST. THIS FLOW
REGIME WILL ALLOW FOR A FEW SHOWERS TO STREAM ACROSS THE ATLANTIC
WATERS AND INTO THE EAST COAST METRO AREAS DURING THIS TIME FRAME
ALONG WITH SLIGHTLY WARMER TEMPERATURES.
BY EARLY NEXT WEEK...A WEAK H5 SHORTWAVE IS FORECAST TO SURGE TO
THE SOUTHEAST ACROSS THE DEEP SOUTH AND INTO NORTHERN FLORIDA. AS
IT DOES...AN ASSOCIATED SURFACE LOW ACROSS THE WESTERN ATLANTIC
WILL PULL TO THE NORTHEAST WRAPPING SOME DEEPER MOISTURE ACROSS
THE FLORIDA PENINSULA RESULTING IN SLIGHT CHANCES FOR SHOWERS ON
MONDAY. AS THE LOW CONTINUES TO MOVE ON...IT WILL SWING A COLD
FRONT THROUGH THE AREA LATE MONDAY INTO TUESDAY WITH A RETURN TO
DRIER CONDITIONS WITH MORE NORTHWEST TO NORTHERLY FLOW AND COOLER
TEMPERATURES.
MARINE...
FRESH NORTH TO NORTHEASTERLY WINDS WILL PREVAIL TODAY AND THROUGH
THE WEEKEND WITH HIGH PRESSURE SITUATED ACROSS THE WESTERN
ATLANTIC. SEAS ACROSS THE GULF WATERS WILL BEGIN TO SUBSIDE
THROUGH THE DAY AS WINDS BECOME MORE OFFSHORE. ACROSS THE
ATLANTIC...SEAS SHOULD REMAIN NEAR ADVISORY LEVELS THROUGH
SATURDAY BEFORE WINDS SUBSIDE SLIGHTLY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 64 77 68 / - - 10 10
FORT LAUDERDALE 73 67 79 71 / - - 10 10
MIAMI 73 65 79 69 / - - 10 10
NAPLES 73 56 81 60 / - - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-
LAKE OKEECHOBEE-WATERS FROM DEERFIELD BEACH TO OCEAN REEF,
FL EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE
BAHAMAS.
SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING
FROM 20 NM TO 60 NM.
GM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...54/BNB
AREA FORECAST DISCUSSION
NWS MIAMI FL
645 AM EST THU NOV 28 2013
.AVIATION...VFR WILL PREVAIL. SKIES WILL BE MOSTLY CLEAR AT KAPF
THROUGH THE PERIOD. FOR THE EAST COAST, EXPECT SCT-BKN STRATO CU
TO INCREASE LATER TODAY...AT AROUND 5K FT. BRIEF MVFR CIGS WILL
CONTINUE IN MIAMI-DADE OVER THE NEXT HOUR BUT ARE EXPECTED TO
IMPROVE. MOISTURE LOOKS TOO SHALLOW TO ADD ANY SHOWER MENTION.
WINDS WILL PREVAIL NW AT NEAR 10 KT. GFS/NAM MOS LIKELY BRINGING
WINDS OUT OF THE NE TOO QUICKLY ATLANTIC TERMINALS. HRRR LOOKS TO
HAVE THE RIGHT IDEA, DELAYING NE WINDS UNTIL 18-19Z. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 406 AM EST THU NOV 28 2013/
DISCUSSION...
TEMPERATURES IN THE LOW TO MID 50S ARE SEEN THIS MORNING ALONG
THE EAST COAST WITH MID TO UPPER 40S ACROSS THE INTERIOR WITH
BRISK NORTHERLY WINDS. WINDS SHOULD BEGIN TO VEER MORE TO THE
NORTHEAST THROUGH THE DAY ALLOWING MORE OF A MARITIME INFLUENCE
AND WEAK MOISTURE RETURN ACROSS THE AREA PARTICULARLY FOR THE
EASTERN HALF OF THE AREA. HOWEVER...GENERALLY RAIN FREE WEATHER
SHOULD PREVAIL THROUGH THE DAY.
NORTHEAST FLOW SHOULD THEN PERSIST THROUGH THE WEEKEND AS HIGH
PRESSURE REMAINS CENTERED JUST OFF THE CAROLINA COAST. THIS FLOW
REGIME WILL ALLOW FOR A FEW SHOWERS TO STREAM ACROSS THE ATLANTIC
WATERS AND INTO THE EAST COAST METRO AREAS DURING THIS TIME FRAME
ALONG WITH SLIGHTLY WARMER TEMPERATURES.
BY EARLY NEXT WEEK...A WEAK H5 SHORTWAVE IS FORECAST TO SURGE TO
THE SOUTHEAST ACROSS THE DEEP SOUTH AND INTO NORTHERN FLORIDA. AS
IT DOES...AN ASSOCIATED SURFACE LOW ACROSS THE WESTERN ATLANTIC
WILL PULL TO THE NORTHEAST WRAPPING SOME DEEPER MOISTURE ACROSS
THE FLORIDA PENINSULA RESULTING IN SLIGHT CHANCES FOR SHOWERS ON
MONDAY. AS THE LOW CONTINUES TO MOVE ON...IT WILL SWING A COLD
FRONT THROUGH THE AREA LATE MONDAY INTO TUESDAY WITH A RETURN TO
DRIER CONDITIONS WITH MORE NORTHWEST TO NORTHERLY FLOW AND COOLER
TEMPERATURES.
MARINE...
FRESH NORTH TO NORTHEASTERLY WINDS WILL PREVAIL TODAY AND THROUGH
THE WEEKEND WITH HIGH PRESSURE SITUATED ACROSS THE WESTERN
ATLANTIC. SEAS ACROSS THE GULF WATERS WILL BEGIN TO SUBSIDE
THROUGH THE DAY AS WINDS BECOME MORE OFFSHORE. ACROSS THE
ATLANTIC...SEAS SHOULD REMAIN NEAR ADVISORY LEVELS THROUGH
SATURDAY BEFORE WINDS SUBSIDE SLIGHTLY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 64 77 68 / - - 10 10
FORT LAUDERDALE 73 67 79 71 / - - 10 10
MIAMI 73 65 79 69 / - - 10 10
NAPLES 73 56 81 60 / - - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING
FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS.
SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING
FROM 20 NM TO 60 NM.
GM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
810 AM CST THU NOV 28 2013
.DISCUSSION...
306 AM CST
THE PRIMARY FORECAST CONCERNS ARE CENTERED ON CLOUD COVER AND
TEMPERATURES THROUGH THE WEEKEND AND THEN CHANCES FOR PRECIPITATION
NEXT WEEK IN WHAT APPEARS TO POSSIBLY BE AN UNSETTLED
PATTERN...ALTHOUGH A HIGH DEGREE OF UNCERTAINTY.
ONE MORE SHORT WAVE IS DIVING SOUTHEAST ACROSS THE GREAT LAKES THIS
THANKSGIVING MORNING IN WHAT HAS BEEN A LITERAL PARADE OF THESE
COLD-AIR-REINFORCING SYSTEMS. A 1017MB SURFACE LOW REFLECTION ACROSS
IA WILL TRANSLATE EAST THIS MORNING AND WEAKEN AS IT DOES SUCH.
MORNING CLOUDS IN PLACE WERE DEVELOPED WITHIN THE WARM AIR ADVECTION
ENVELOPE OF THIS SYSTEM AND AS SUCH HAVE BASES MAINLY ABOVE 5000
FT...SO BELIEVE THEY WILL VACATE BY AFTERNOON ACROSS THE WESTERN AND
SOUTHERN FORECAST AREA GIVEN THE CLOUD-BEARING WIND FLOW. LOW-LEVEL
LAPSE RATES ARE MODESTLY STEEP BEHIND THE SYSTEM WITH SOME MARGINAL
SATURATION FORECAST AT THE TOP OF THE MIXED LAYER...SO LIKELY SOME
SCATTERED STRATOCU WILL CONTINUE. ALL-IN-ALL...EXPECTING SOME SUN
LATE THIS MORNING AND AFTERNOON. GIVEN THE 850MB AND 925MB FORECAST
TEMPS BY THE RAP AND NAM THIS AFTERNOON...WE ONCE AGAIN ARE IN THE
BOTTOM TENTH PERCENTILE FOR THIS TIME OF YEAR. THIS FAVORS HIGHS IN
THE LOWER TO MID 30S. SEE THE CLIMATE DISCUSSION BELOW FOR MORE ON
WHERE THIS STACKS UP FOR THANKSGIVING DAYS.
AS A CANADIAN SURFACE HIGH MOVES OVERHEAD TONIGHT TEMPERATURES
SHOULD RADIATE QUICKLY THIS EVE...EVEN IF IT DOES TAKE A FEW HOURS
AFTER SUNSET TO DIMINISH THE LINGERING STRATOCU. HAVE MID AND EVEN
PATCHY LOWER TEENS IN OUTLYING AREAS. AS THE WIND FIELD OVER LAKE MI
SHIFTS MORE NE TONIGHT IMMEDIATELY AHEAD OF THE HIGH CENTER...A LAKE
PLUME OF AT LEAST CLOUDS LOOKS LIKELY INTO NORTHWEST INDIANA AND
POSSIBLY NORTHEAST ILLINOIS. LAKE-INDUCED EQUILIBRIUM LEVELS AROUND
4500 FT FORECAST BY THE NAM SEEM A LITTLE SHALLOW FOR PRECIP AND ANY
PRONOUNCED CONVERGENCE IS UNLIKELY. HAVE THUS ONLY ADDED A LOW
CHANCE FOR SOME LIGHT SNOW IN NORTHWEST IN/FAR SOUTHEAST COOK COUNTY
LATE TONIGHT AS WELL AS BUMPED UP CLOUD COVER.
A MORE ZONAL PATTERN WILL MOVE OVER BY LATER FRIDAY INTO SATURDAY
BRINGING MODERATING TEMPERATURES. THERE IS A FAIR AMOUNT OF SPREAD
IN THE ENVELOPE OF GUIDANCE SOLUTIONS FOR HOW WARM SATURDAY WILL
BE...AND POTENTIAL CLOUD COVER LIKELY HAS QUITE A BIT TO DO WITH
THAT. THIS TIME OF YEAR SOUTHERLY LOW-LEVEL FLOW AFTER A COLD AIR
MASS CAN READILY BECOME "CONTAMINATED" WITH SATURATION/CLOUDS.
CLIMATOLOGY OF THE 850MB AND 925MB TEMPERATURES WOULD FAVOR MID AND
MAYBE EVEN UPPER 40S...BUT THAT WARM CURRENTLY SEEMS UNLIKELY WITH
AT LEAST SOME POTENTIAL FOR CLOUDS AND NOT THE STRONGEST OF WARM AIR
ADVECTION SIGNALS. THE HEART OF THE SYSTEM IS OVER THE NORTHERN
GREAT LAKES...SO FORCING AND SATURATION REMAINS MINIMAL OVER THE
AREA. SO HAVE NO POPS AT THIS TIME.
NEXT WEEK THE UNCERTAINTY REALLY STARTS TO RAMP UP BY MIDWEEK AFTER
WHAT IS BECOMING A MORE FAVORED DRY SUNDAY AND MONDAY. ALTHOUGH MUCH
LIKE SATURDAY...TEMPERATURE CONFIDENCE IS FAIRLY LOW GIVEN CLOUD
POTENTIAL. IF CLOUDS ARE REMAINING INTO SUNDAY MORNING THEY VERY
WELL COULD STICK AROUND ALL THE WAY THROUGH MONDAY NIGHT AS SURFACE
PRESSURES ARE FORECAST TO BASICALLY REMAIN THE SAME...I.E. LITTLE
ADVECTION. THE LONG ADVERTISED UPPER TROUGH ACROSS THE WEST COAST
LOOKS TO EVOLVE IN THE BEGINNING OF THE WEEK AND FORCE DOWNSTREAM
RIDGING AND SOUTHWEST FLOW ALOFT. THIS TROUGH SHOULD PACK QUITE A
PUNCH OF COLD AIR INTO THE NORTHERN ROCKIES AND PLAINS...BUT THE
MAIN BAROCLINIC ZONE DURING MIDWEEK LOOKS TO REMAIN TO THE NORTHWEST
AND IF THAT IS THE CASE THEN ANY HEAVY WINTER PRECIP SHOULD AS WELL
DURING MIDWEEK...BUT AGAIN CONFIDENCE IS LOW. ENERGY THAT TRANSLATES
EAST FROM THIS TROUGH APPEARS TO BE IN PARTS AND THUS MULTIPLE
CHANCES FOR PRECIP LOOK TO BE THE CASE ACROSS THE GREAT LAKES AND
CORN BELT REGIONS DURING THE DEC 3-8 PERIOD. NIGHTTIME TEMPERATURES
SHOULD BE MORE NEAR NORMAL OR EVEN ABOVE NORMAL GIVEN CLOUD
COVER DURING MIDWEEK...BUT DAYTIME HIGHS COULD BE ANYWHERE IN A
LARGE SPECTRUM OF SOLUTIONS DEPENDING ON STRENGTH OF SOUTHERLY
FLOW AND WHEN LOW PASSAGES OCCUR. THOSE ARE BOTH VARIABLES DIFFICULT
TO LOCK DOWN IN A FORECAST PATTERN OF A BROAD TROUGH IN THE WEST.
MTF
&&
.CLIMATE...
306 AM CST
THE FORECAST HIGH TODAY FOR CHICAGO (O`HARE) IS 33 WHICH WOULD TIE
MULTIPLE THANKSGIVINGS IN THE PAST TWO DECADES FOR A COOL
HIGH...THE LAST BEING 2007. HOWEVER IF THE MERCURY STAYS BELOW
THAT...IT WOULD BE THE COLDEST HIGH TEMPERATURE ON THANKSGIVING IN
CHICAGO SINCE 1989.
SIMILARLY FOR ROCKFORD...THE 31 DEGREE FORECAST HIGH WOULD BE THE
COOLEST THANKSGIVING HIGH SINCE 1995 AND IF IT STAYS BELOW THAT IT
WOULD BE THE COOLEST SINCE 1989.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* WIND SHIFT FROM SOUTHWEST TO NORTHWEST TOWARD 20Z.
* VFR EXPECTED TO CONTINUE BUT THERE IS A LOW CHANCE FOR A PERIOD
OF MVFR CIGS LATER THIS AFTERNOON.
MDB/RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE RIDGING HAS SHIFTED OFF TO THE EAST OF THE TERMINALS
ALLOWING A STEADIER SOUTHERLY FLOW TO SET UP. AN UPPER LEVEL
TROUGH IS CURRENTLY CROSSING THE AREA WITH ASSOCIATED PRECIP
REMAINING NORTHEAST OF THE AREA. VFR CLOUD SHIELD WITH BASES OF
6000-7000 FT CONTINUES TO MOVE EASTWARD WITH THE BACK EDGE OF IT
COMING INTO NORTH CENTRAL ILLINOIS. HAVE GONE AHEAD AND REDUCED
CLOUD COVER OVER THE NEXT FEW HOURS AS SATELLITE SUPPORTS THIS
CLOUD BAND EXITING TO THE EAST OF THE TERMINALS. COVERAGE COULD BE
MUCH LESS THAN THE SCT INCLUDED IN THE TAFS BUT SOME ADDITIONAL
CUMULUS COULD DEVELOP.
SOUTH TO SOUTHWEST WINDS WILL CONTINUE THROUGH THE MORNING THEN
TURN WEST AND THEN NORTHWEST WITH THE PASSAGE OF A COLD FRONTAL
BOUNDARY THIS AFTERNOON. CLOUD COVER TO THE NORTH OF THE AREA
LOOKS TO WORK SOUTHWARD INTO THE AREA LATER THIS AFTERNOON. EXPECT
THE BULK OF THIS TO BE VFR BUT SOME MVFR MAY DEVELOP FOR A BRIEF
PERIOD. WINDS WILL DIMINISH LATER THIS EVENING WHILE TRYING TO
TURN MORE NORTHERLY OVERNIGHT WITH ANY LATE DAY CLOUD COVER
EXITING THE AREA LEAVING LITTLE IN THE WAY OF SKY COVER GOING INTO
FRIDAY MORNING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* LOW CONFIDENCE IN MVFR POTENTIAL THIS AFTERNOON.
MDB/RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...VFR.
SUNDAY AND MONDAY...MVFR POSSIBLE,
TUESDAY...VFR.
WEDNESDAY...CHANCE SHRA...MVFR POSSIBLE.
MDB
&&
.MARINE...
221 AM CST
THE MAIN FOCUS OF THE FORECAST CONTINUES TO BE THE POTENTIAL FOR
GALE FORCE WINDS LATE FRIDAY NIGHT THROUGH MIDDAY/EARLY AFTERNOON
SATURDAY...MAINLY ACROSS THE NORTH HALF OF THE LAKE.
CURRENTLY...SURFACE LOW PRESSURE CONTINUES TO DEEPEN AS IT MOVES
NORTHWARD INTO EASTERN QUEBEC AND NEWFOUNDLAND. HIGH PRESSURE
RIDGING IS CROSSING LAKE MICHIGAN EARLY THIS MORNING WITH A WEAK
AREA OF LOW PRESSURE OVER WESTERN MINNESOTA AND NORTHWEST IOWA.
THIS LOW WILL MOVE ACROSS NORTHERN LAKE MICHIGAN LATER TODAY AND
THIS EVENING. WINDS HAVE TURNED WEST AND SOUTHWEST THANKS TO THE
PASSAGE OF THE RIDGE AXIS WITH SPEEDS DIMINISHING BUT THEY WILL
INCREASE SOMEWHAT AS THE LOW CROSSES THE AREA LATER TODAY. A
NARROW CORRIDOR OF OFFSHORE SOUTHEASTERLY WINDS IS OCCURRING ALONG
THE MICHIGAN SHORE BUT WILL DIMINISH THROUGH MID MORNING. WINDS
ACROSS FAR NORTHERN LAKE MICHIGAN WILL BE TRICKY AS THE LOW CENTER
IS EXPECTED TO CROSS THIS AREA THIS AFTERNOON. THIS WILL LIKELY
LEAD TO AN EASTERLY SURFACE FLOW OVER FAR NORTHERN LAKE MICHIGAN
LATER THIS MORNING AND THIS AFTERNOON...WHILE THE REST OF THE LAKE
SEES WEST TO SOUTHWEST WINDS. A COOL FRONTAL BOUNDARY WILL CROSS
THE LAKE LATER TODAY TURNING WINDS TO THE NORTHWEST. HIGH PRESSURE
WILL SPREAD IN BEHIND THE FRONT AND STRENGTHEN AS IT CROSSES THE
LAKE FRIDAY BEFORE SHIFTING TO THE EAST. THIS WILL TURN WINDS BACK
TO THE SOUTH BY FRIDAY AFTERNOON WITH RATHER LIGHT SPEEDS.
THE HIGH WILL CONTINUE TO STRENGTHEN AS IT MOVES ACROSS THE NORTHEAST
U.S. WHILE A CLIPPER DROPS SOUTHEAST ACROSS WESTERN ONTARIO JUST
NORTH OF LAKE SUPERIOR SATURDAY. THE PRESSURE GRADIENT WILL TIGHTEN
BETWEEN THESE TWO SYSTEMS LEADING TO STRONG SOUTH TO SOUTHWEST WINDS
LATE FRIDAY NIGHT AND SATURDAY MORNING. THE STRONGEST SPEEDS WILL
OCCUR ACROSS NORTHERN PORTIONS OF THE LAKE. WILL HOLD WINDS TO 30 KT
FOR NOW WITH THE STRONGEST WINDS NORTH...BUT AM CONCERNED THAT AN
INCREASE TO GALES MAY BE NEEDED. THIS SYSTEM IS NOT TOO UNLIKE
SEVERAL WHICH WE SAW EARLIER THIS FALL THAT FEATURED SURFACE LOWS
PASSING TO THE NORTH AND WINDS THAT WERE HIGHER THAN EXPECTED. THIS
MAY NOT BE THE CASE WITH THIS PARTICULAR SYSTEM BUT IT IS WORTH
NOTING GIVEN THAT UNSTABLE CONDITIONS WILL BE IN PLACE ACROSS THE
LAKE SIMILAR TO THESE EARLIER SYSTEMS. A COLD FRONT CROSSES THE
LAKE SATURDAY AFTERNOON ALLOWING WINDS TO DROP OFF SATURDAY
EVENING. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE REGION
SUNDAY AND CONTINUE TO KEEP LIGHTER WINDS IN PLACE THROUGH
TUESDAY. FORECAST CONFIDENCE DROPS OFF BY WEDNESDAY BUT IT DOES
APPEAR THAT A MORE ACTIVE PATTERN WILL BE SETTING UP BRINGING
INCREASING CHANCES FOR STRONGER WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
540 AM CST THU NOV 28 2013
.DISCUSSION...
306 AM CST
THE PRIMARY FORECAST CONCERNS ARE CENTERED ON CLOUD COVER AND
TEMPERATURES THROUGH THE WEEKEND AND THEN CHANCES FOR PRECIPITATION
NEXT WEEK IN WHAT APPEARS TO POSSIBLY BE AN UNSETTLED
PATTERN...ALTHOUGH A HIGH DEGREE OF UNCERTAINTY.
ONE MORE SHORT WAVE IS DIVING SOUTHEAST ACROSS THE GREAT LAKES THIS
THANKSGIVING MORNING IN WHAT HAS BEEN A LITERAL PARADE OF THESE
COLD-AIR-REINFORCING SYSTEMS. A 1017MB SURFACE LOW REFLECTION ACROSS
IA WILL TRANSLATE EAST THIS MORNING AND WEAKEN AS IT DOES SUCH.
MORNING CLOUDS IN PLACE WERE DEVELOPED WITHIN THE WARM AIR ADVECTION
ENVELOPE OF THIS SYSTEM AND AS SUCH HAVE BASES MAINLY ABOVE 5000
FT...SO BELIEVE THEY WILL VACATE BY AFTERNOON ACROSS THE WESTERN AND
SOUTHERN FORECAST AREA GIVEN THE CLOUD-BEARING WIND FLOW. LOW-LEVEL
LAPSE RATES ARE MODESTLY STEEP BEHIND THE SYSTEM WITH SOME MARGINAL
SATURATION FORECAST AT THE TOP OF THE MIXED LAYER...SO LIKELY SOME
SCATTERED STRATOCU WILL CONTINUE. ALL-IN-ALL...EXPECTING SOME SUN
LATE THIS MORNING AND AFTERNOON. GIVEN THE 850MB AND 925MB FORECAST
TEMPS BY THE RAP AND NAM THIS AFTERNOON...WE ONCE AGAIN ARE IN THE
BOTTOM TENTH PERCENTILE FOR THIS TIME OF YEAR. THIS FAVORS HIGHS IN
THE LOWER TO MID 30S. SEE THE CLIMATE DISCUSSION BELOW FOR MORE ON
WHERE THIS STACKS UP FOR THANKSGIVING DAYS.
AS A CANADIAN SURFACE HIGH MOVES OVERHEAD TONIGHT TEMPERATURES
SHOULD RADIATE QUICKLY THIS EVE...EVEN IF IT DOES TAKE A FEW HOURS
AFTER SUNSET TO DIMINISH THE LINGERING STRATOCU. HAVE MID AND EVEN
PATCHY LOWER TEENS IN OUTLYING AREAS. AS THE WIND FIELD OVER LAKE MI
SHIFTS MORE NE TONIGHT IMMEDIATELY AHEAD OF THE HIGH CENTER...A LAKE
PLUME OF AT LEAST CLOUDS LOOKS LIKELY INTO NORTHWEST INDIANA AND
POSSIBLY NORTHEAST ILLINOIS. LAKE-INDUCED EQUILIBRIUM LEVELS AROUND
4500 FT FORECAST BY THE NAM SEEM A LITTLE SHALLOW FOR PRECIP AND ANY
PRONOUNCED CONVERGENCE IS UNLIKELY. HAVE THUS ONLY ADDED A LOW
CHANCE FOR SOME LIGHT SNOW IN NORTHWEST IN/FAR SOUTHEAST COOK COUNTY
LATE TONIGHT AS WELL AS BUMPED UP CLOUD COVER.
A MORE ZONAL PATTERN WILL MOVE OVER BY LATER FRIDAY INTO SATURDAY
BRINGING MODERATING TEMPERATURES. THERE IS A FAIR AMOUNT OF SPREAD
IN THE ENVELOPE OF GUIDANCE SOLUTIONS FOR HOW WARM SATURDAY WILL
BE...AND POTENTIAL CLOUD COVER LIKELY HAS QUITE A BIT TO DO WITH
THAT. THIS TIME OF YEAR SOUTHERLY LOW-LEVEL FLOW AFTER A COLD AIR
MASS CAN READILY BECOME "CONTAMINATED" WITH SATURATION/CLOUDS.
CLIMATOLOGY OF THE 850MB AND 925MB TEMPERATURES WOULD FAVOR MID AND
MAYBE EVEN UPPER 40S...BUT THAT WARM CURRENTLY SEEMS UNLIKELY WITH
AT LEAST SOME POTENTIAL FOR CLOUDS AND NOT THE STRONGEST OF WARM AIR
ADVECTION SIGNALS. THE HEART OF THE SYSTEM IS OVER THE NORTHERN
GREAT LAKES...SO FORCING AND SATURATION REMAINS MINIMAL OVER THE
AREA. SO HAVE NO POPS AT THIS TIME.
NEXT WEEK THE UNCERTAINTY REALLY STARTS TO RAMP UP BY MIDWEEK AFTER
WHAT IS BECOMING A MORE FAVORED DRY SUNDAY AND MONDAY. ALTHOUGH MUCH
LIKE SATURDAY...TEMPERATURE CONFIDENCE IS FAIRLY LOW GIVEN CLOUD
POTENTIAL. IF CLOUDS ARE REMAINING INTO SUNDAY MORNING THEY VERY
WELL COULD STICK AROUND ALL THE WAY THROUGH MONDAY NIGHT AS SURFACE
PRESSURES ARE FORECAST TO BASICALLY REMAIN THE SAME...I.E. LITTLE
ADVECTION. THE LONG ADVERTISED UPPER TROUGH ACROSS THE WEST COAST
LOOKS TO EVOLVE IN THE BEGINNING OF THE WEEK AND FORCE DOWNSTREAM
RIDGING AND SOUTHWEST FLOW ALOFT. THIS TROUGH SHOULD PACK QUITE A
PUNCH OF COLD AIR INTO THE NORTHERN ROCKIES AND PLAINS...BUT THE
MAIN BAROCLINIC ZONE DURING MIDWEEK LOOKS TO REMAIN TO THE NORTHWEST
AND IF THAT IS THE CASE THEN ANY HEAVY WINTER PRECIP SHOULD AS WELL
DURING MIDWEEK...BUT AGAIN CONFIDENCE IS LOW. ENERGY THAT TRANSLATES
EAST FROM THIS TROUGH APPEARS TO BE IN PARTS AND THUS MULTIPLE
CHANCES FOR PRECIP LOOK TO BE THE CASE ACROSS THE GREAT LAKES AND
CORN BELT REGIONS DURING THE DEC 3-8 PERIOD. NIGHTTIME TEMPERATURES
SHOULD BE MORE NEAR NORMAL OR EVEN ABOVE NORMAL GIVEN CLOUD
COVER DURING MIDWEEK...BUT DAYTIME HIGHS COULD BE ANYWHERE IN A
LARGE SPECTRUM OF SOLUTIONS DEPENDING ON STRENGTH OF SOUTHERLY
FLOW AND WHEN LOW PASSAGES OCCUR. THOSE ARE BOTH VARIABLES DIFFICULT
TO LOCK DOWN IN A FORECAST PATTERN OF A BROAD TROUGH IN THE WEST.
MTF
&&
.CLIMATE...
306 AM CST
THE FORECAST HIGH TODAY FOR CHICAGO (O`HARE) IS 33 WHICH WOULD TIE
MULTIPLE THANKSGIVINGS IN THE PAST TWO DECADES FOR A COOL
HIGH...THE LAST BEING 2007. HOWEVER IF THE MERCURY STAYS BELOW
THAT...IT WOULD BE THE COLDEST HIGH TEMPERATURE ON THANKSGIVING IN
CHICAGO SINCE 1989.
SIMILARLY FOR ROCKFORD...THE 31 DEGREE FORECAST HIGH WOULD BE THE
COOLEST THANKSGIVING HIGH SINCE 1995 AND IF IT STAYS BELOW THAT IT
WOULD BE THE COOLEST SINCE 1989.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* WINDS SHIFT FROM SOUTHWEST TO NORTHWEST TOWARD 20Z.
* VFR EXPECTED TO CONTINUE BUT THERE IS A LOW CHANCE FOR A PERIOD
OF MVFR CIGS LATER THIS AFTERNOON.
MDB
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE RIDGING HAS SHIFTED OFF TO THE EAST OF THE TERMINALS
ALLOWING A STEADIER SOUTHERLY FLOW TO SET UP. AN UPPER LEVEL
TROUGH IS CURRENTLY CROSSING THE AREA WITH ASSOCIATED PRECIP
REMAINING NORTHEAST OF THE AREA. VFR CLOUD SHIELD WITH BASES OF
6000-7000 FT CONTINUES TO MOVE EASTWARD WITH THE BACK EDGE OF IT
COMING INTO NORTH CENTRAL ILLINOIS. HAVE GONE AHEAD AND REDUCED
CLOUD COVER OVER THE NEXT FEW HOURS AS SATELLITE SUPPORTS THIS
CLOUD BAND EXITING TO THE EAST OF THE TERMINALS. COVERAGE COULD BE
MUCH LESS THAN THE SCT INCLUDED IN THE TAFS BUT SOME ADDITIONAL
CUMULUS COULD DEVELOP.
SOUTH TO SOUTHWEST WINDS WILL CONTINUE THROUGH THE MORNING THEN
TURN WEST AND THEN NORTHWEST WITH THE PASSAGE OF A COLD FRONTAL
BOUNDARY THIS AFTERNOON. CLOUD COVER TO THE NORTH OF THE AREA
LOOKS TO WORK SOUTHWARD INTO THE AREA LATER THIS AFTERNOON. EXPECT
THE BULK OF THIS TO BE VFR BUT SOME MVFR MAY DEVELOP FOR A BRIEF
PERIOD. WINDS WILL DIMINISH LATER THIS EVENING WHILE TRYING TO
TURN MORE NORTHERLY OVERNIGHT WITH ANY LATE DAY CLOUD COVER
EXITING THE AREA LEAVING LITTLE IN THE WAY OF SKY COVER GOING INTO
FRIDAY MORNING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* LOW CONFIDENCE IN MVFR POTENTIAL THIS AFTERNOON.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...VFR.
SUNDAY AND MONDAY...MVFR POSSIBLE,
TUESDAY...VFR.
WEDNESDAY...CHANCE SHRA...MVFR POSSIBLE.
MDB
&&
.MARINE...
221 AM CST
THE MAIN FOCUS OF THE FORECAST CONTINUES TO BE THE POTENTIAL FOR
GALE FORCE WINDS LATE FRIDAY NIGHT THROUGH MIDDAY/EARLY AFTERNOON
SATURDAY...MAINLY ACROSS THE NORTH HALF OF THE LAKE.
CURRENTLY...SURFACE LOW PRESSURE CONTINUES TO DEEPEN AS IT MOVES
NORTHWARD INTO EASTERN QUEBEC AND NEWFOUNDLAND. HIGH PRESSURE
RIDGING IS CROSSING LAKE MICHIGAN EARLY THIS MORNING WITH A WEAK
AREA OF LOW PRESSURE OVER WESTERN MINNESOTA AND NORTHWEST IOWA.
THIS LOW WILL MOVE ACROSS NORTHERN LAKE MICHIGAN LATER TODAY AND
THIS EVENING. WINDS HAVE TURNED WEST AND SOUTHWEST THANKS TO THE
PASSAGE OF THE RIDGE AXIS WITH SPEEDS DIMINISHING BUT THEY WILL
INCREASE SOMEWHAT AS THE LOW CROSSES THE AREA LATER TODAY. A
NARROW CORRIDOR OF OFFSHORE SOUTHEASTERLY WINDS IS OCCURRING ALONG
THE MICHIGAN SHORE BUT WILL DIMINISH THROUGH MID MORNING. WINDS
ACROSS FAR NORTHERN LAKE MICHIGAN WILL BE TRICKY AS THE LOW CENTER
IS EXPECTED TO CROSS THIS AREA THIS AFTERNOON. THIS WILL LIKELY
LEAD TO AN EASTERLY SURFACE FLOW OVER FAR NORTHERN LAKE MICHIGAN
LATER THIS MORNING AND THIS AFTERNOON...WHILE THE REST OF THE LAKE
SEES WEST TO SOUTHWEST WINDS. A COOL FRONTAL BOUNDARY WILL CROSS
THE LAKE LATER TODAY TURNING WINDS TO THE NORTHWEST. HIGH PRESSURE
WILL SPREAD IN BEHIND THE FRONT AND STRENGTHEN AS IT CROSSES THE
LAKE FRIDAY BEFORE SHIFTING TO THE EAST. THIS WILL TURN WINDS BACK
TO THE SOUTH BY FRIDAY AFTERNOON WITH RATHER LIGHT SPEEDS.
THE HIGH WILL CONTINUE TO STRENGTHEN AS IT MOVES ACROSS THE NORTHEAST
U.S. WHILE A CLIPPER DROPS SOUTHEAST ACROSS WESTERN ONTARIO JUST
NORTH OF LAKE SUPERIOR SATURDAY. THE PRESSURE GRADIENT WILL TIGHTEN
BETWEEN THESE TWO SYSTEMS LEADING TO STRONG SOUTH TO SOUTHWEST WINDS
LATE FRIDAY NIGHT AND SATURDAY MORNING. THE STRONGEST SPEEDS WILL
OCCUR ACROSS NORTHERN PORTIONS OF THE LAKE. WILL HOLD WINDS TO 30 KT
FOR NOW WITH THE STRONGEST WINDS NORTH...BUT AM CONCERNED THAT AN
INCREASE TO GALES MAY BE NEEDED. THIS SYSTEM IS NOT TOO UNLIKE
SEVERAL WHICH WE SAW EARLIER THIS FALL THAT FEATURED SURFACE LOWS
PASSING TO THE NORTH AND WINDS THAT WERE HIGHER THAN EXPECTED. THIS
MAY NOT BE THE CASE WITH THIS PARTICULAR SYSTEM BUT IT IS WORTH
NOTING GIVEN THAT UNSTABLE CONDITIONS WILL BE IN PLACE ACROSS THE
LAKE SIMILAR TO THESE EARLIER SYSTEMS. A COLD FRONT CROSSES THE
LAKE SATURDAY AFTERNOON ALLOWING WINDS TO DROP OFF SATURDAY
EVENING. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE REGION
SUNDAY AND CONTINUE TO KEEP LIGHTER WINDS IN PLACE THROUGH
TUESDAY. FORECAST CONFIDENCE DROPS OFF BY WEDNESDAY BUT IT DOES
APPEAR THAT A MORE ACTIVE PATTERN WILL BE SETTING UP BRINGING
INCREASING CHANCES FOR STRONGER WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS GOODLAND KS
446 AM MST THU NOV 28 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 358 AM MST THU NOV 28 2013
FORECAST PROBLEM WILL BE TEMPERATURES. SATELLITE SHOWING AN
AMPLIFIED PATTERN FROM THE PACIFIC INTO EASTERN NORTH AMERICA.
SOUTHERN PORTION OF THE TROUGH ALONG THE WEST COAST HAS SPLIT AND
CUT OFF FROM THE NORTHERN PORTION. THIS IS LEAVING A STRONG RIDGE
OVER THE WESTERN PORTION OF THE COUNTRY WITH NORTHWEST FLOW ALOFT
OVER THE AREA. DRY AIR MASS AT ALL LEVELS IS IN PLACE ACROSS THE
REGION.
MODELS DID FINE AT UPPER LEVELS. AT MID LEVELS...THE GFS WAS DOING
THE BEST WITH THE UKMET NOT TOO FAR BEHIND IT. THE NAM WAS DOING A
LITTLE BETTER THAN THE ECMWF ON THE SURFACE WIND AND PRESSURE
FIELD. NAM AND ECMWF WERE DOING A LITTLE BETTER THAN THE GFS AND
CANADIAN ON THE LOW LEVEL THERMAL FIELD.
TODAY/TONIGHT...INTERESTING AND TRICKY TEMPERATURE FORECAST. SHALLOW
COLD FRONT WAS BEGINNING TO PUSH THROUGH THE AREA AND SHOULD BE
THROUGH MOST OF THE AREA BY 12Z TODAY. COLD AIR ADVECTION WILL
CONTINUE THROUGH THE DAY AS SURFACE BECOME EASTERLY. SOME THIN HIGH
LEVEL CLOUD COVER MAY COME IN DURING THE DAY AND CONTINUE INTO
TONIGHT BUT DO NOT EXPECT IT TO BE HAMPER WARMING. WHAT MAY IMPACT
HIGH TEMPERATURES TODAY IS LARGE AREA OF STRATUS MOVING SOUTH
ACROSS NEBRASKA AT THIS TIME.
THE RAP AND NAM TENDED TO CATCH THIS BUT WERE EITHER NOT FAR ENOUGH
SOUTH OR WEST WITH THIS AREA. TAKING THOSE MODELS AT FACE VALUE
WOULD SAY THAT STRATUS AND MAYBE SOME FOG WILL MOVE INTO THE
NORTHEAST PORTION OF THE AREA THIS MORNING. THE RAP IS THE MOST
AGGRESSIVE AND KEEPS THE COLDEST TEMPERATURES THERE. AFTER
COLLABORATION...ALL I DID WAS INCREASE CLOUD COVER A LITTLE.
HOWEVER WILL CONTINUE TO MONITOR TRENDS FOR AS LONG AS POSSIBLE AND
MAKE ANY NEEDED ADJUSTMENTS. TENDED TO COOLER IN THE NORTHEAST AND
WARMER IN THE WEST AND SOUTHWEST.
FOR TONIGHT MORE THAN MODEL IS NOW CONSISTENT IN BRINGING STRATUS IN
RETURN FLOW BY LATER THIS EVENING INTO THE OVERNIGHT HOURS. THE NAM
IS THE MOST AGGRESSIVE BUT THE ECMWF...GFS AND SREF ARE NOT FAR
BEHIND. WITH THIS NEW DATA AND COLLABORATION...KEPT THE FREEZING
FOG AND INCREASED THE SKY COVER AFTER 06Z. DEPENDING ON HOW FAST THE
STRATUS COMES IN...EASTERN LOCATIONS COULD DROP QUICKLY.
FRIDAY/FRIDAY NIGHT...STRATUS LOOKS TO HANG ON THROUGH THE MORNING
WHICH COULD IMPACT TEMPERATURES...ESPECIALLY IF IT HANGS ON LONGER.
MODELS STILL WAFFLING BACK AND FORTH AS TO HOW FAR BACK EAST TO TAKE
THE COLD AIR/COLD FRONT. EARLIER OUTPUT TENDED TO KEEP THE COLD AIR
FARTHER WEST WHILE THE NEWER OUTPUT IS NOW FURTHER EAST. ONE THING
FOR SURE...WILL DEFINITELY HAVE QUITE A GRADIENT IN TEMPERATURES
WITH A HIGH DEGREE OF UNCERTAINTY/POTENTIAL TO BE VERY WRONG.
SATURDAY/SATURDAY NIGHT...MODELS THEN START HAVING PROBLEMS IN
RESOLVING THE MID AND UPPER LEVEL FLOW WITH LITTLE AGREEMENT SHOWN BY
THE OUTPUT. WEST NORTHWEST TO NORTHWEST FLOW ALOFT WITH EMBEDDED
SHORTWAVES COME THROUGH DURING THIS TIME. THE STRONGEST ONE MOVES
ACROSS THE NORTH CENTRAL PORTION OF THE COUNTRY. THIS PUSHES
ANOTHER COLD FRONT THROUGH FROM LATE IN THE MORNING INTO THE EARLY
AFTERNOON. THE BRUNT OF THE COOLING LOOKS TO OCCUR OVER THE EASTERN
THIRD TO HALF. SO ONCE AGAIN THERE COULD BE A BIG GRADIENT IN
TEMPERATURES ACROSS THE AREA. CURRENT GRIDS HAD THIS LAYOUT
CAPTURED WELL AND ONLY MADE SLIGHT ADJUSTMENTS. BUT THERE IS
POTENTIAL THAT THESE TEMPERATURES WILL NEED TO BE ADJUSTED IF THE
SPEED AND POSITION OF THIS FRONT CHANGES.
THANKS TO ALL FOR THE COLLABORATION.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM MST THU NOV 28 2013
H5 ZONAL FLOW AND H3 CONFLUENCE WILL BE IN PLACE THROUGH THE EARLY
PART OF THE WEEK...WHICH WILL SUPPORT LARGE SCALE STABLE/DRY
CONDITIONS OVER MUCH OF THE PLAINS. SURFACE TO H85 W-SW FLOW
ASSOCIATED WITH LEE TROUGH DEVELOPMENT ALONG THE KS/CO BORDER WILL
SUPPORT WAA AND MILD TEMPERATURES ACROSS THE REGION. A WEAK COLD
FRONT OVER THE NORTHERN PLAINS WILL LIFT NORTH AND EAST SUNDAY WITH
HIGHS WARMING TO LOW TO MID 50S. CONTINUED MODERATION OF AIR MASS ON
MONDAY SHOULD SUPPORT HIGHS AT LEAST IN THE MID 50S. ECMWF MOS
CONTINUES TO SHOW HIGHS IN UPPER 50S/NEAR 60F AND BASED ON WARM
EPISODES IN THE SHORT TERM THIS MIGHT BE REASONABLE.
TUESDAY-WEDNESDAY NIGHT...LESS CONFIDENCE IN THESE PERIODS REGARDING
FINER DETAILS OF TEMPS/PRECIP CHANCES...HOWEVER GUIDANCE CONTINUES
TO ADVERTISE A LARGE SCALE SHIFT IN THE PATTERN ACROSS THE WESTERN
US. A STRONG UPPER LOW ORIGINATING OVER ALASKA IS ADVERTISED TO DROP
SOUTH ALONG AMPLIFIED PACIFIC RIDGE INTO THE PACIFIC NW BY MONDAY
NIGHT PULLING WITH IT A STRONG ARCTIC AIR MASS FROM POLAR REGIONS
INTO THE NORTHERN PLAINS. GEM IS THE FASTEST ON ARCTIC FRONT MOVING
INTO OUR CWA TUESDAY EVENING...HOWEVER LAST FEW RUNS OF
ECMWF/GFS/GEFS LEAN TOWARDS A SLOWER FRONTAL TIMING (POSSIBLY AS
LATE AS WED NIGHT). THERE IS A LARGE AMOUNT OF SPREAD REGARDING THE
EVOLUTION OF THE UPPER LOW IN THE WESTERN US...WHICH WILL IMPACT
ONSET OF PRECIPITATION AND THE MAGNITUDE OF COLD AIR. YESTERDAYS 12Z
RUN OF ECMWF WAS AN EXTREME (AND CONCERNING) OUTLIER WITH H85 TEMPS
BY NEXT THU -20C OR COLDER OVER PARTS OF OUR CWA. LATEST RUN OF
ECWMF AND GFS ARE A LITTLE MORE IN LINE...HOWEVER BOTH WOULD SUPPORT
VERY COLD TEMPERATURES SETTLING IN BY AT LEAST THE LATER PART OF
NEXT WEEK. CONSIDERING THE PATTERN SHOULD SUPPORT AT LEAST BREEZY
CONDITIONS AND VERY COLD OVERNIGHT TEMPS WE MAY END UP SEEING THE
NEED FOR A WIND CHILL ADVISORY (WC VALUES LESS/EQUAL TO -15F) OR
WARNING IF THE EXTREME SPECTRUM OF GUIDANCE WERE TO VERIFY. I TEND
TO LEAN TOWARD THE MODEL MEAN AT THIS POINT FOR TUE/WED CONSIDERING
RUN-RUN DIFFERENCES WHICH SHOWS COLDER TEMPS AND BETTER PRECIP
CHANCES DELAYED TOWARDS WED/WED NIGHT AND OUTSIDE OUR CURRENT VALID
FORECAST PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 441 AM MST THU NOV 28 2013
MAIN PROBLEMS TO DEAL WITH ARE STRATUS NEAR KMCK IN THE FIRST PART
OF THE PERIOD AND STRATUS FOR BOTH SITES...ESPECIALLY AT KGLD...TOWARD
THE END OF THE PERIOD. COLD FRONT HAS MOVED THROUGH BOTH SITES. A
LARGE AREA OF STRATUS HAS BEEN MOVING SOUTH ACROSS NEBRASKA. THIS
AREA IS STILL WELL TO THE NORTHEAST OF KMCK. AT THIS TIME IT LOOKS
LIKE THE EDGE OF THIS STRATUS FIELD WILL COME CLOSE TO KMCK. SO
FROM MID MORNING UNTIL EARLY AFTERNOON PUT IN A SCATTERED LOW DECK
WITH A TEMPO GROUP COVERING THE POSSIBILITY OF A MVFR CEILING.
LATER TONIGHT AS SOUTHERLY WINDS INCREASE ON THE WEST SIDE OF THE
EXITING SURFACE HIGH...LOW LEVEL MOISTURE WILL BE DRAWN NORTHWARD.
AT THIS TIME IT LOOK LIKE KGLD HAVE MVFR CEILINGS DEVELOP AFTER
06Z. IT LOOKS LIKE ANY CEILINGS WILL STAY TO THE WEST OF KMCK AT
THIS TIME.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...DJR
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
358 AM MST THU NOV 28 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 358 AM MST THU NOV 28 2013
FORECAST PROBLEM WILL BE TEMPERATURES. SATELLITE SHOWING AN
AMPLIFIED PATTERN FROM THE PACIFIC INTO EASTERN NORTH AMERICA.
SOUTHERN PORTION OF THE TROUGH ALONG THE WEST COAST HAS SPLIT AND
CUT OFF FROM THE NORTHERN PORTION. THIS IS LEAVING A STRONG RIDGE
OVER THE WESTERN PORTION OF THE COUNTRY WITH NORTHWEST FLOW ALOFT
OVER THE AREA. DRY AIR MASS AT ALL LEVELS IS IN PLACE ACROSS THE
REGION.
MODELS DID FINE AT UPPER LEVELS. AT MID LEVELS...THE GFS WAS DOING
THE BEST WITH THE UKMET NOT TOO FAR BEHIND IT. THE NAM WAS DOING A
LITTLE BETTER THAN THE ECMWF ON THE SURFACE WIND AND PRESSURE
FIELD. NAM AND ECMWF WERE DOING A LITTLE BETTER THAN THE GFS AND
CANADIAN ON THE LOW LEVEL THERMAL FIELD.
TODAY/TONIGHT...INTERESTING AND TRICKY TEMPERATURE FORECAST. SHALLOW
COLD FRONT WAS BEGINNING TO PUSH THROUGH THE AREA AND SHOULD BE
THROUGH MOST OF THE AREA BY 12Z TODAY. COLD AIR ADVECTION WILL
CONTINUE THROUGH THE DAY AS SURFACE BECOME EASTERLY. SOME THIN HIGH
LEVEL CLOUD COVER MAY COME IN DURING THE DAY AND CONTINUE INTO
TONIGHT BUT DO NOT EXPECT IT TO BE HAMPER WARMING. WHAT MAY IMPACT
HIGH TEMPERATURES TODAY IS LARGE AREA OF STRATUS MOVING SOUTH
ACROSS NEBRASKA AT THIS TIME.
THE RAP AND NAM TENDED TO CATCH THIS BUT WERE EITHER NOT FAR ENOUGH
SOUTH OR WEST WITH THIS AREA. TAKING THOSE MODELS AT FACE VALUE
WOULD SAY THAT STRATUS AND MAYBE SOME FOG WILL MOVE INTO THE
NORTHEAST PORTION OF THE AREA THIS MORNING. THE RAP IS THE MOST
AGGRESSIVE AND KEEPS THE COLDEST TEMPERATURES THERE. AFTER
COLLABORATION...ALL I DID WAS INCREASE CLOUD COVER A LITTLE.
HOWEVER WILL CONTINUE TO MONITOR TRENDS FOR AS LONG AS POSSIBLE AND
MAKE ANY NEEDED ADJUSTMENTS. TENDED TO COOLER IN THE NORTHEAST AND
WARMER IN THE WEST AND SOUTHWEST.
FOR TONIGHT MORE THAN MODEL IS NOW CONSISTENT IN BRINGING STRATUS IN
RETURN FLOW BY LATER THIS EVENING INTO THE OVERNIGHT HOURS. THE NAM
IS THE MOST AGGRESSIVE BUT THE ECMWF...GFS AND SREF ARE NOT FAR
BEHIND. WITH THIS NEW DATA AND COLLABORATION...KEPT THE FREEZING
FOG AND INCREASED THE SKY COVER AFTER 06Z. DEPENDING ON HOW FAST THE
STRATUS COMES IN...EASTERN LOCATIONS COULD DROP QUICKLY.
FRIDAY/FRIDAY NIGHT...STRATUS LOOKS TO HANG ON THROUGH THE MORNING
WHICH COULD IMPACT TEMPERATURES...ESPECIALLY IF IT HANGS ON LONGER.
MODELS STILL WAFFLING BACK AND FORTH AS TO HOW FAR BACK EAST TO TAKE
THE COLD AIR/COLD FRONT. EARLIER OUTPUT TENDED TO KEEP THE COLD AIR
FARTHER WEST WHILE THE NEWER OUTPUT IS NOW FURTHER EAST. ONE THING
FOR SURE...WILL DEFINITELY HAVE QUITE A GRADIENT IN TEMPERATURES
WITH A HIGH DEGREE OF UNCERTAINTY/POTENTIAL TO BE VERY WRONG.
SATURDAY/SATURDAY NIGHT...MODELS THEN START HAVING PROBLEMS IN
RESOLVING THE MID AND UPPER LEVEL FLOW WITH LITTLE AGREEMENT SHOWN BY
THE OUTPUT. WEST NORTHWEST TO NORTHWEST FLOW ALOFT WITH EMBEDDED
SHORTWAVES COME THROUGH DURING THIS TIME. THE STRONGEST ONE MOVES
ACROSS THE NORTH CENTRAL PORTION OF THE COUNTRY. THIS PUSHES
ANOTHER COLD FRONT THROUGH FROM LATE IN THE MORNING INTO THE EARLY
AFTERNOON. THE BRUNT OF THE COOLING LOOKS TO OCCUR OVER THE EASTERN
THIRD TO HALF. SO ONCE AGAIN THERE COULD BE A BIG GRADIENT IN
TEMPERATURES ACROSS THE AREA. CURRENT GRIDS HAD THIS LAYOUT
CAPTURED WELL AND ONLY MADE SLIGHT ADJUSTMENTS. BUT THERE IS
POTENTIAL THAT THESE TEMPERATURES WILL NEED TO BE ADJUSTED IF THE
SPEED AND POSITION OF THIS FRONT CHANGES.
THANKS TO ALL FOR THE COLLABORATION.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM MST THU NOV 28 2013
H5 ZONAL FLOW AND H3 CONFLUENCE WILL BE IN PLACE THROUGH THE EARLY
PART OF THE WEEK...WHICH WILL SUPPORT LARGE SCALE STABLE/DRY
CONDITIONS OVER MUCH OF THE PLAINS. SURFACE TO H85 W-SW FLOW
ASSOCIATED WITH LEE TROUGH DEVELOPMENT ALONG THE KS/CO BORDER WILL
SUPPORT WAA AND MILD TEMPERATURES ACROSS THE REGION. A WEAK COLD
FRONT OVER THE NORTHERN PLAINS WILL LIFT NORTH AND EAST SUNDAY WITH
HIGHS WARMING TO LOW TO MID 50S. CONTINUED MODERATION OF AIR MASS ON
MONDAY SHOULD SUPPORT HIGHS AT LEAST IN THE MID 50S. ECMWF MOS
CONTINUES TO SHOW HIGHS IN UPPER 50S/NEAR 60F AND BASED ON WARM
EPISODES IN THE SHORT TERM THIS MIGHT BE REASONABLE.
TUESDAY-WEDNESDAY NIGHT...LESS CONFIDENCE IN THESE PERIODS REGARDING
FINER DETAILS OF TEMPS/PRECIP CHANCES...HOWEVER GUIDANCE CONTINUES
TO ADVERTISE A LARGE SCALE SHIFT IN THE PATTERN ACROSS THE WESTERN
US. A STRONG UPPER LOW ORIGINATING OVER ALASKA IS ADVERTISED TO DROP
SOUTH ALONG AMPLIFIED PACIFIC RIDGE INTO THE PACIFIC NW BY MONDAY
NIGHT PULLING WITH IT A STRONG ARCTIC AIR MASS FROM POLAR REGIONS
INTO THE NORTHERN PLAINS. GEM IS THE FASTEST ON ARCTIC FRONT MOVING
INTO OUR CWA TUESDAY EVENING...HOWEVER LAST FEW RUNS OF
ECMWF/GFS/GEFS LEAN TOWARDS A SLOWER FRONTAL TIMING (POSSIBLY AS
LATE AS WED NIGHT). THERE IS A LARGE AMOUNT OF SPREAD REGARDING THE
EVOLUTION OF THE UPPER LOW IN THE WESTERN US...WHICH WILL IMPACT
ONSET OF PRECIPITATION AND THE MAGNITUDE OF COLD AIR. YESTERDAYS 12Z
RUN OF ECMWF WAS AN EXTREME (AND CONCERNING) OUTLIER WITH H85 TEMPS
BY NEXT THU -20C OR COLDER OVER PARTS OF OUR CWA. LATEST RUN OF
ECWMF AND GFS ARE A LITTLE MORE IN LINE...HOWEVER BOTH WOULD SUPPORT
VERY COLD TEMPERATURES SETTLING IN BY AT LEAST THE LATER PART OF
NEXT WEEK. CONSIDERING THE PATTERN SHOULD SUPPORT AT LEAST BREEZY
CONDITIONS AND VERY COLD OVERNIGHT TEMPS WE MAY END UP SEEING THE
NEED FOR A WIND CHILL ADVISORY (WC VALUES LESS/EQUAL TO -15F) OR
WARNING IF THE EXTREME SPECTRUM OF GUIDANCE WERE TO VERIFY. I TEND
TO LEAN TOWARD THE MODEL MEAN AT THIS POINT FOR TUE/WED CONSIDERING
RUN-RUN DIFFERENCES WHICH SHOWS COLDER TEMPS AND BETTER PRECIP
CHANCES DELAYED TOWARDS WED/WED NIGHT AND OUTSIDE OUR CURRENT VALID
FORECAST PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1029 PM MST WED NOV 27 2013
VFR CONDITIONS WILL PREVAIL ACROSS THE CENTRAL HIGH PLAINS REGION
AND THE MCK AND GLD TAF SITES THROUGH THE TAF PERIOD. LIGHT
NORTHWEST TO WEST WINDS WILL TURN NORTHEASTERLY BY 19Z THURSDAY AS
THE SURFACE HIGH PRESSURE AREA OVER THE NORTHERN PLAINS MOVES INTO
THE CENTRAL PLAINS STATES. WINDS WILL REMAIN LIGHT AND TURN
TO THE SOUTH AS THE HIGH MOVES OFF TO THE EAST AND A LEE TROUGH
DEEPENS ALONG THE FRONT RANGE AFTER 00Z FRIDAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...DJR
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
650 AM EST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EST THU NOV 28 2013
LARGE SCALE FIRST...THEN LETS TALK ABOUT MESOSCALE AND LK EFFECT
ISSUES THAT ARE PLENTY. SHORTWAVE AND LOW PRESSURE TROUGH IN COOL NW
FLOW CLOSING IN ON WESTERN UPR MICHIGAN. BATCH OF LGT SNOW EXTENDS
FROM FAR WEST CWA TO THE NORTHWEST ALONG MN/ONTARIO BORDER. SO
WIDESPREAD LGT SNOW WILL IMPACT THOSE TRAVELING THIS THANKSGIVING
MORNING...ESPECIALLY OVER WESTERN CWA AND TOWARD WISCONSIN BORDER
WHERE BETTER FORCING WITH THE SHORTWAVE RESIDES. OMEGA IN THE H7-H6
LAYER EXITS AFT 15Z...LEAVING MOSTLY NEGATIVE LARGE SCALE FORCING
THROUGH TONIGHT.
NOW ONTO THE MESOSCALE AND LAKE EFFECT ISSUES. IT IS NEVER A GOOD
THING WHEN A LARGER SCALE TROUGH MERGES INTO AN UNSTABLE AND LIGHT
WIND LAKE EFFECT ENVIRONMENT. CRAZY THINGS CAN HAPPEN. TODAY MAY END
UP BEING ONE OF THESE DAYS. ONLY TIME WILL TELL. LK EFFECT IS ALREADY
ONGOING. FIRST FOR LK SUPERIOR...STRONG MESOLOW CIRCULATION IS TAKING
OFF JUST OFFSHORE OF MUNSING AND MAY ACTUALLY BE CLIPPING GRAND
ISLAND. THIS IS LIKELY THE BEGINNING OF EVENTUAL HEAVY SNOW BAND TO
IMPACT FAR NORTHERN KEWEENAW PENINSULA...VCNTY OF DELAWARE AND COPPER
HARBOR...THOUGH MIDDAY. WINDS OVER LK SUPERIOR ARE MAINLY NE AT THIS
TIME...BUT TOWARD THE SOUTH SHORE ARE BECOMING VARIABLE OR EVEN SOUTH
THANKS TO APPROACHING LOW PRESSURE TROUGH AND LAND BREEZES /ACTUALLY
SAW TEMPS DIP BLO ZERO OVR PARTS OF INTERIOR EASTERN UPR MICHIGAN
THIS MORNING SHOWING THE CHILL OF THE AIRMASS/. AS THE MORNING WEARS
ON...INCREASING SOUTH WINDS WILL CONVERGE WITH ENE WINDS OVR LK
SUPERIOR RESULTING IN DOMINANT BAND OF SNOW OVR TIP OF KEWEENAW.
ALREADY SEEING ECHOES ON MQT RADAR NEAR COPPER HARBOR BUT NOTHING YET
PER THE KEWEENAW CO SHERIFF IN EAGLE RIVER. 00Z NAM SEEMED TOO QUICK
IN SWINGING DOMINANT BAND BACK TO SOUTH THIS AFTN. 06Z NAM ADJUSTED
AND NOW LOOKS LIKE PREFERRED 00Z GEM-REGIONAL AND LOCAL WRF-ARW AND
RUC13. UPSHOT IS HEAVIER SNOW HANGS OUT ON TIP OF KEWEENAW THROUGH
MIDDAY THEN SINKS SOUTH WITH MORE BRIEF HEAVIER SNOW SOUTH OF CALUMET
BY MID-LATE AFTN. OVERALL THE GOING LK EFFECT SNOW ADVY LOOKS
GOOD...THOUGH ISOLD AMOUNTS UP TO 10 INCHES NOT OUT QUESTION IF BAND
STAYS IN SAME LOCATION.
NOT ALL ABOUT LK SUPERIOR THOUGH AS LK MICHIGAN COULD BE INTERESTING
AS WELL. SOUTH WINDS FORMING ON LK MICHIGAN ARE LEADING TO CONCERNS
THAT LK EFFECT...POSSIBLY HEAVY...COULD IMPACT PARTS OF DELTA AND
SOUTHERN SCHOOLCRAFT INTO THIS AFTN. GRB/APX RADAR ALREADY SHOWING
SIGNS OF LK EFFECT MESO FEATURES ALONG DOOR PENINSULA AND ALONG NW
SHORE OF NORTHERN LOWER MICHIGAN. RUC13 SFC CONVERGENCE FIELD DOING
VERY NICE JOB OF PEGGING THESE AREAS AND IT SHOWS THEM MERGING OVER
FAR NORTHERN LK MICHIGAN AFT 15Z AND AFFECTING MAINLY GARDEN
PENINSULA ACROSS SOUTHERN SCHOOLCRAFT ZONE THIS AFTN. WAS VERY CLOSE
TO GO WITH ADVY...BUT CONFIDENCE WAS NOT THERE AS THESE IS UNCERTAINTY
IN HOW FAR NORTH THESE CIRCULATIONS WILL GET. RUC FCST IS VERIFYING
WELL THOUGH AND DOES GET A LOT OF MERIT. SO...WILL PASS THIS ON TO
DAYSHIFT AND LET THEM SEE HOW THINGS LOOK AFT DAYBREAK. PUT OUT A
STRONGLY WORDED SPS AND MENTIONED THAT EITHER ADVY/WARNING COULD BE
NEEDED LATER TODAY. ANYTHING IS POSSIBLE IN THIS KIND OF SETUP.
TONIGHT WILL BASICALLY BE AN EXTENSION OF HOW LK EFFECT DEVELOPS
TODAY...SO IT IS STILL KIND OF UNCERTAIN. LEANED ON NCEP HIGH RES
WRF-ARW AND NMM RUNS AS WELL AS NAM WHICH COMES BACK INTO LINE WITH
GOING THINKING. GENERALLY...SFC TROUGH SHOULD MOVE TO EASTERN LK
SUPERIOR ALLOWING WINDS TO BECOME MORE NW OR WEST OVR MUCH OF UPR
MICHIGAN. FIRST IMPACT WILL BE TO SHUNT LK EFFECT OFF LK MICHIGAN
BACK TO THE SOUTH. HAVE CHANCES VERY EARLY IN THE EVENING...THEN
DROP THEM TO SLIGHTS BY LATE EVENING. FARTHER NORTH...LK EFFECT SNOW
SHOWERS WILL BE AFFECTING NORTHWEST CWA LATE AFTN/EARLY EVENING AND
SHOULD SINK TOWARD NCNTRL UPR MICHIGAN...BIG BAY/MARQUETTE THROUGH
THE EVENING AND OVERNIGHT HOURS AND EVENTUALLY MAKE IT ONSHORE TO
EAST OF MARQUETTE TOWARD MUNISING AND GRAND MARAIS LATER TONIGHT.
MODERATE ACCUMS COULD OCCUR TONIGHT FOR HIGHER TERRAIN OF
WEST...VCNTY OF PORCUPINE MTS AND SETUP SEEMS GOOD FOR CONVERGENT
BAND OF SNOW TO AFFECT GOOD PART OF BARAGA COUNTY...MAYBE EVEN RIGHT
ALONG LK SHORE AT BARAGA/L`ANSE AS WELL. FOR NOW HAVE 2-4 INCHES IN
THERE FOR THESE AREAS THIS EVENING. LOCALLY HEAVY SNOW MAY SPREAD TO
BIG BAY/MARQUETTE LATER TONIGHT AS CONVERGENCE MAXIMIZES BTWN NW WINDS
OVER LK SUPERIOR AND POSSIBLE LAND BREEZE OVER CNTRL UPR MICHIGAN.
INLAND FM ALL THE LK EFFECT AND CLOUDS...SOME CLEARING AND LIGHTER
WINDS MAY ALLOW TEMPS TO FALL INTO THE SINGLE DIGITS TOWARD WI
BORDER AND OVER INTERIOR EASTERN CWA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 505 AM EST THU NOV 28 2013
FRIDAY...A SPRAWLING SFC HIGH FROM NRN ONTARIO INTO THE OHIO VALLEY
WILL RESULT IN A VERY WEAK GRADIENT ACROSS THE NRN GREAT LAKES. THE
HIGH RES MODELS SUGGEST THAT THE CIRCULATION AROUND A LAKE INDUCED
LOW OR TROUGH OVER SE LAKE SUPERIOR COULD FOCUS LES BANDS ANYWHERE FROM
MARQUETTE TO MUNISING. IF THE LOW LEVEL CONVERGENCE IS STRONG ENOUGH
THERE MAY BE A PERIOD OF HEAVY SNOW. HOWEVER...CONFIDENCE IN THE
LOCATION AND DURATION OF SUCH A BAND IS LOW. SO...FCST SNOWFALL
AMOUNTS WERE LIMITED TO AROUND AN INCH. DEVELOPING SRLY FLOW IN THE
AFTERNOON WILL PUSH THE REMAINING LES OFFSHORE. ANY SNOWBANDS MOVING
INTO THE WEST SHOULD ALSO WEAKEN AND POSSIBLY LINGER ALONG THE
SHORELINE UNTIL AFTERNOON WHEN OFF SHORE WINDS STRENGTHEN. 850 MB WAA
WILL INCREASE IN THE AFTERNOON AS WEAK MID LEVEL RIDGING MOVES BACK
OVER THE AREA AND A SFC HIGH BUILDS INTO THE ERN LAKES. HIGH TEMPS
ARE EXPECTED TO REBOUND INTO THE MID AND UPPER 20S.
FRI NIGHT AND SAT...THE MODELS WERE IN GOOD AGREEMENT WITH THE NEXT
CLIPPER SHORTWAVE TROUGH SLIDING ACROSS NRN LAKE SUPERIOR LATE IN THE
DAY ON SATURDAY. LIGHT SNOW DEVELOPING OVER SCNTRL CANADA IN THE WAA
PATTERN AHEAD OF THE SHORTWAVE WILL SPREAD SNOW ACROSS NRN LAKE
SUPERIOR FRI NIGHT PERHAPS BRUSHING THE NRN AND ERN COUNTIES WITH
SOME LIGHT SNOW LATE FRI NIGHT INTO SAT. THE STRONGER FORCING AND
BETTER SNOW POTENTIAL IS EXPECTED TO REMAIN NORTH OF LAKE SUPERIOR.
HOWEVER...THERE MAY ALSO BE A PERIOD OF LAKE ENAHCNED SNOW INTO THE
ERN CWA FROM LATE FRI NIGHT INTO SAT WITH SSW LOW LEVEL FLOW OFF OF LAKE
MI VEERING TO THE SW. THE LONG FETCH WILL BE FAVORABLE BUT
INSTABILITY WILL BE LIMITED WITH RELATIVELY DRY AIR OVER THE AREA
BEFORE THE SHRTWV ARRIVES AND WAA PUSHING 850 MB TEMPS -8C TO -5C.
SAT NIGHT...SOME LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE
WAKE OF THE SFC TROUGH AS WINDS VEER FROM NW TO N AND 850 MB TEMPS
DROP FROM -10C TO -12C. WITH ONLY MARGINAL INSTABILITY...ONLY CHANCE
POPS WERE INCLUDED.
SUN INTO MON...AS HIGH PRES BUILDS INTO NRN ONTARIO WINDS WILL
CONTINUE TO VEER FROM NNE TO E. 850 MB TEMPS AROUND -12C WILL
PROVIDE JUST ENOUGH INSTABILITY TO KEEP LES CHANCES GOING ACROSS
NORTH CENTRAL UPPER MICHIGAN AND THE KEWEENAW. NEAR NORMAL TEMPS ARE
EXPECTED WITH HIGHS AROUND 30 TO THE LOWER 30S AND LOWS IN THE LOWER
20S.
TUE AND WED...MODELS DIFFER WITH THE APPROACH OF THE NEXT
SHORTWAVE EMERGING FROM THE WRN CONUS TROF. THE GFS INDICATES A MORE
POSITIVE-TILT WRN CONUS TROF AND LESS AMPLIFICATION OF RIDGE
DOWNSTREAM ALLOWING FOR A QUICKER ADVANCE OF A SHORTWAVE AND ASSOCIATED
FRONTAL SYSTEM INTO THE WRN LAKES. THE ECMWF INDICATES A MORE
AMPLIFIED PATTERN ACROSS THE CONUS WITH A SLOWER ADVANCE OF THE
SHORTWAVE MOVING TOWARD THE WRN LAKES. THE FCST CONTINUED TO USE A
MDLS CONSENSUS THAT REFLECTS A SLIGHTLY LATER ARRIVAL OF PCPN
CHANCES FROM TUE NIGHT INTO WED. THE MODELS ALSO TRENDED TOWARD A
LESS AMPLIFIED SOLUTION WITH COLDER AIR ACROSS THE NRN LAKES WHICH
WOULD REDUCE THE CHANCE FOR ANY RAIN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 649 AM EST THU NOV 28 2013
FCST WILL BE A CHALLENGE OVER THE NEXT 24HRS. WITH DISTURBANCE
APPROACHING FROM THE NW...WINDS HAVE SWUNG AROUND TO A LIGHT S TO
SW DIRECTION. -SN ASSOCIATED WITH APPROACHING DISTURBANCE WILL
AFFECT ALL THE TAF SITES WITH MAINLY MVFR CONDITIONS THIS MORNING.
OTHERWISE...FOCUS WILL SHIFT TO MESOLOW DEVELOPING OVER WRN LAKE
SUPERIOR THIS MORNING. AS THE LOW SHIFTS INTO WRN UPPER MI THIS
AFTN...A PERIOD OF MDT TO POTENTIALLY HVY SNOW WILL IMPACT KIWD/KCMX
AS WINDS SHIFT TO AN ONSHORE DIRECTION. FOR NOW...INCLUDED IFR
CONDITIONS AT BOTH TERMINALS FOR SEVERAL HRS IN THE AFTN TO EVENING.
OCNL LIFR CONDITIONS NOT OUT OF THE QUESTION. BEST SHOT OF THAT WILL
BE AT CMX SO INCLUDED TEMPO GROUP. KSAW SHOULD GENERALLY REMAIN VFR
INTO THE AFTN BEFORE WINDS BECOME LIGHT NRLY. MIGHT BE A PERIOD OF
HEAVIER SHSN/LOWER CONDITIONS AT KSAW THIS EVENING. &&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 343 PM EST WED NOV 27 2013
STRONGER N WINDS WILL CONTINUE TO SLOWLY DIMINISH THIS EVENING. A
RIDGE OF HIGH PRESSURE WILL EXTEND OVER LAKE SUPERIOR THIS
EVENING...WHILE A WEAK LOW OVER THE EASTERN DAKOTAS PUSHES ACROSS
THE UPPER GREAT LAKES LATE TONIGHT THROUGH THURSDAY. LARGER HIGH
PRESSURE EXTENDING ACROSS MUCH OF CENTRAL CANADA THROUGH THE CENTRAL
PLAINS THURSDAY AFTERNOON WILL SWING ACROSS THE UPPER GREAT LAKES
THURSDAY NIGHT...BEFORE EXITING TO THE LOWER GREAT LAKES AND NEW
ENGLAND STATES FRIDAY AFTERNOON THROUGH SATURDAY. EXPECT A LOW OVER
LAKE WINNIPEG FRIDAY NIGHT TO PUSH ACROSS SOUTHERN ONTARIO AND LAKE
SUPERIOR SATURDAY AND SATURDAY EVENING. THERE IS THE POTENTIAL FOR
30KT S GUSTS DURING THE DAY SATURDAY. FOR SUNDAY AND MONDAY...HIGH
PRESSURE SCOOTING ACROSS ONTARIO WILL PUSH A RIDGE OVER LAKE
SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
MIZ001.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...JLB
AVIATION...JLA
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
521 AM EST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EST THU NOV 28 2013
LARGE SCALE FIRST...THEN LETS TALK ABOUT MESOSCALE AND LK EFFECT
ISSUES THAT ARE PLENTY. SHORTWAVE AND LOW PRESSURE TROUGH IN COOL NW
FLOW CLOSING IN ON WESTERN UPR MICHIGAN. BATCH OF LGT SNOW EXTENDS
FROM FAR WEST CWA TO THE NORTHWEST ALONG MN/ONTARIO BORDER. SO
WIDESPREAD LGT SNOW WILL IMPACT THOSE TRAVELING THIS THANKSGIVING
MORNING...ESPECIALLY OVER WESTERN CWA AND TOWARD WISCONSIN BORDER
WHERE BETTER FORCING WITH THE SHORTWAVE RESIDES. OMEGA IN THE H7-H6
LAYER EXITS AFT 15Z...LEAVING MOSTLY NEGATIVE LARGE SCALE FORCING
THROUGH TONIGHT.
NOW ONTO THE MESOSCALE AND LAKE EFFECT ISSUES. IT IS NEVER A GOOD
THING WHEN A LARGER SCALE TROUGH MERGES INTO AN UNSTABLE AND LIGHT
WIND LAKE EFFECT ENVIRONMENT. CRAZY THINGS CAN HAPPEN. TODAY MAY END
UP BEING ONE OF THESE DAYS. ONLY TIME WILL TELL. LK EFFECT IS ALREADY
ONGOING. FIRST FOR LK SUPERIOR...STRONG MESOLOW CIRCULATION IS TAKING
OFF JUST OFFSHORE OF MUNSING AND MAY ACTUALLY BE CLIPPING GRAND
ISLAND. THIS IS LIKELY THE BEGINNING OF EVENTUAL HEAVY SNOW BAND TO
IMPACT FAR NORTHERN KEWEENAW PENINSULA...VCNTY OF DELAWARE AND COPPER
HARBOR...THOUGH MIDDAY. WINDS OVER LK SUPERIOR ARE MAINLY NE AT THIS
TIME...BUT TOWARD THE SOUTH SHORE ARE BECOMING VARIABLE OR EVEN SOUTH
THANKS TO APPROACHING LOW PRESSURE TROUGH AND LAND BREEZES /ACTUALLY
SAW TEMPS DIP BLO ZERO OVR PARTS OF INTERIOR EASTERN UPR MICHIGAN
THIS MORNING SHOWING THE CHILL OF THE AIRMASS/. AS THE MORNING WEARS
ON...INCREASING SOUTH WINDS WILL CONVERGE WITH ENE WINDS OVR LK
SUPERIOR RESULTING IN DOMINANT BAND OF SNOW OVR TIP OF KEWEENAW.
ALREADY SEEING ECHOES ON MQT RADAR NEAR COPPER HARBOR BUT NOTHING YET
PER THE KEWEENAW CO SHERIFF IN EAGLE RIVER. 00Z NAM SEEMED TOO QUICK
IN SWINGING DOMINANT BAND BACK TO SOUTH THIS AFTN. 06Z NAM ADJUSTED
AND NOW LOOKS LIKE PREFERRED 00Z GEM-REGIONAL AND LOCAL WRF-ARW AND
RUC13. UPSHOT IS HEAVIER SNOW HANGS OUT ON TIP OF KEWEENAW THROUGH
MIDDAY THEN SINKS SOUTH WITH MORE BRIEF HEAVIER SNOW SOUTH OF CALUMET
BY MID-LATE AFTN. OVERALL THE GOING LK EFFECT SNOW ADVY LOOKS
GOOD...THOUGH ISOLD AMOUNTS UP TO 10 INCHES NOT OUT QUESTION IF BAND
STAYS IN SAME LOCATION.
NOT ALL ABOUT LK SUPERIOR THOUGH AS LK MICHIGAN COULD BE INTERESTING
AS WELL. SOUTH WINDS FORMING ON LK MICHIGAN ARE LEADING TO CONCERNS
THAT LK EFFECT...POSSIBLY HEAVY...COULD IMPACT PARTS OF DELTA AND
SOUTHERN SCHOOLCRAFT INTO THIS AFTN. GRB/APX RADAR ALREADY SHOWING
SIGNS OF LK EFFECT MESO FEATURES ALONG DOOR PENINSULA AND ALONG NW
SHORE OF NORTHERN LOWER MICHIGAN. RUC13 SFC CONVERGENCE FIELD DOING
VERY NICE JOB OF PEGGING THESE AREAS AND IT SHOWS THEM MERGING OVER
FAR NORTHERN LK MICHIGAN AFT 15Z AND AFFECTING MAINLY GARDEN
PENINSULA ACROSS SOUTHERN SCHOOLCRAFT ZONE THIS AFTN. WAS VERY CLOSE
TO GO WITH ADVY...BUT CONFIDENCE WAS NOT THERE AS THESE IS UNCERTAINTY
IN HOW FAR NORTH THESE CIRCULATIONS WILL GET. RUC FCST IS VERIFYING
WELL THOUGH AND DOES GET A LOT OF MERIT. SO...WILL PASS THIS ON TO
DAYSHIFT AND LET THEM SEE HOW THINGS LOOK AFT DAYBREAK. PUT OUT A
STRONGLY WORDED SPS AND MENTIONED THAT EITHER ADVY/WARNING COULD BE
NEEDED LATER TODAY. ANYTHING IS POSSIBLE IN THIS KIND OF SETUP.
TONIGHT WILL BASICALLY BE AN EXTENSION OF HOW LK EFFECT DEVELOPS
TODAY...SO IT IS STILL KIND OF UNCERTAIN. LEANED ON NCEP HIGH RES
WRF-ARW AND NMM RUNS AS WELL AS NAM WHICH COMES BACK INTO LINE WITH
GOING THINKING. GENERALLY...SFC TROUGH SHOULD MOVE TO EASTERN LK
SUPERIOR ALLOWING WINDS TO BECOME MORE NW OR WEST OVR MUCH OF UPR
MICHIGAN. FIRST IMPACT WILL BE TO SHUNT LK EFFECT OFF LK MICHIGAN
BACK TO THE SOUTH. HAVE CHANCES VERY EARLY IN THE EVENING...THEN
DROP THEM TO SLIGHTS BY LATE EVENING. FARTHER NORTH...LK EFFECT SNOW
SHOWERS WILL BE AFFECTING NORTHWEST CWA LATE AFTN/EARLY EVENING AND
SHOULD SINK TOWARD NCNTRL UPR MICHIGAN...BIG BAY/MARQUETTE THROUGH
THE EVENING AND OVERNIGHT HOURS AND EVENTUALLY MAKE IT ONSHORE TO
EAST OF MARQUETTE TOWARD MUNISING AND GRAND MARAIS LATER TONIGHT.
MODERATE ACCUMS COULD OCCUR TONIGHT FOR HIGHER TERRAIN OF
WEST...VCNTY OF PORCUPINE MTS AND SETUP SEEMS GOOD FOR CONVERGENT
BAND OF SNOW TO AFFECT GOOD PART OF BARAGA COUNTY...MAYBE EVEN RIGHT
ALONG LK SHORE AT BARAGA/L`ANSE AS WELL. FOR NOW HAVE 2-4 INCHES IN
THERE FOR THESE AREAS THIS EVENING. LOCALLY HEAVY SNOW MAY SPREAD TO
BIG BAY/MARQUETTE LATER TONIGHT AS CONVERGENCE MAXIMIZES BTWN NW WINDS
OVER LK SUPERIOR AND POSSIBLE LAND BREEZE OVER CNTRL UPR MICHIGAN.
INLAND FM ALL THE LK EFFECT AND CLOUDS...SOME CLEARING AND LIGHTER
WINDS MAY ALLOW TEMPS TO FALL INTO THE SINGLE DIGITS TOWARD WI
BORDER AND OVER INTERIOR EASTERN CWA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 505 AM EST THU NOV 28 2013
FRIDAY...A SPRAWLING SFC HIGH FROM NRN ONTARIO INTO THE OHIO VALLEY
WILL RESULT IN A VERY WEAK GRADIENT ACROSS THE NRN GREAT LAKES. THE
HIGH RES MODELS SUGGEST THAT THE CIRCULATION AROUND A LAKE INDUCED
LOW OR TROUGH OVER SE LAKE SUPERIOR COULD FOCUS LES BANDS ANYWHERE FROM
MARQUETTE TO MUNISING. IF THE LOW LEVEL CONVERGENCE IS STRONG ENOUGH
THERE MAY BE A PERIOD OF HEAVY SNOW. HOWEVER...CONFIDENCE IN THE
LOCATION AND DURATION OF SUCH A BAND IS LOW. SO...FCST SNOWFALL
AMOUNTS WERE LIMITED TO AROUND AN INCH. DEVELOPING SRLY FLOW IN THE
AFTERNOON WILL PUSH THE REMAINING LES OFFSHORE. ANY SNOWBANDS MOVING
INTO THE WEST SHOULD ALSO WEAKEN AND POSSIBLY LINGER ALONG THE
SHORELINE UNTIL AFTERNOON WHEN OFF SHORE WINDS STRENGTHEN. 850 MB WAA
WILL INCREASE IN THE AFTERNOON AS WEAK MID LEVEL RIDGING MOVES BACK
OVER THE AREA AND A SFC HIGH BUILDS INTO THE ERN LAKES. HIGH TEMPS
ARE EXPECTED TO REBOUND INTO THE MID AND UPPER 20S.
FRI NIGHT AND SAT...THE MODELS WERE IN GOOD AGREEMENT WITH THE NEXT
CLIPPER SHORTWAVE TROUGH SLIDING ACROSS NRN LAKE SUPERIOR LATE IN THE
DAY ON SATURDAY. LIGHT SNOW DEVELOPING OVER SCNTRL CANADA IN THE WAA
PATTERN AHEAD OF THE SHORTWAVE WILL SPREAD SNOW ACROSS NRN LAKE
SUPERIOR FRI NIGHT PERHAPS BRUSHING THE NRN AND ERN COUNTIES WITH
SOME LIGHT SNOW LATE FRI NIGHT INTO SAT. THE STRONGER FORCING AND
BETTER SNOW POTENTIAL IS EXPECTED TO REMAIN NORTH OF LAKE SUPERIOR.
HOWEVER...THERE MAY ALSO BE A PERIOD OF LAKE ENAHCNED SNOW INTO THE
ERN CWA FROM LATE FRI NIGHT INTO SAT WITH SSW LOW LEVEL FLOW OFF OF LAKE
MI VEERING TO THE SW. THE LONG FETCH WILL BE FAVORABLE BUT
INSTABILITY WILL BE LIMITED WITH RELATIVELY DRY AIR OVER THE AREA
BEFORE THE SHRTWV ARRIVES AND WAA PUSHING 850 MB TEMPS -8C TO -5C.
SAT NIGHT...SOME LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE
WAKE OF THE SFC TROUGH AS WINDS VEER FROM NW TO N AND 850 MB TEMPS
DROP FROM -10C TO -12C. WITH ONLY MARGINAL INSTABILITY...ONLY CHANCE
POPS WERE INCLUDED.
SUN INTO MON...AS HIGH PRES BUILDS INTO NRN ONTARIO WINDS WILL
CONTINUE TO VEER FROM NNE TO E. 850 MB TEMPS AROUND -12C WILL
PROVIDE JUST ENOUGH INSTABILITY TO KEEP LES CHANCES GOING ACROSS
NORTH CENTRAL UPPER MICHIGAN AND THE KEWEENAW. NEAR NORMAL TEMPS ARE
EXPECTED WITH HIGHS AROUND 30 TO THE LOWER 30S AND LOWS IN THE LOWER
20S.
TUE AND WED...MODELS DIFFER WITH THE APPROACH OF THE NEXT
SHORTWAVE EMERGING FROM THE WRN CONUS TROF. THE GFS INDICATES A MORE
POSITIVE-TILT WRN CONUS TROF AND LESS AMPLIFICATION OF RIDGE
DOWNSTREAM ALLOWING FOR A QUICKER ADVANCE OF A SHORTWAVE AND ASSOCIATED
FRONTAL SYSTEM INTO THE WRN LAKES. THE ECMWF INDICATES A MORE
AMPLIFIED PATTERN ACROSS THE CONUS WITH A SLOWER ADVANCE OF THE
SHORTWAVE MOVING TOWARD THE WRN LAKES. THE FCST CONTINUED TO USE A
MDLS CONSENSUS THAT REFLECTS A SLIGHTLY LATER ARRIVAL OF PCPN
CHANCES FROM TUE NIGHT INTO WED. THE MODELS ALSO TRENDED TOWARD A
LESS AMPLIFIED SOLUTION WITH COLDER AIR ACROSS THE NRN LAKES WHICH
WOULD REDUCE THE CHANCE FOR ANY RAIN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1206 AM EST THU NOV 28 2013
FCST WILL BE A CHALLENGE OVER THE NEXT 24HRS. WITH DISTURBANCE
APPROACHING FROM THE NW...WINDS ARE IN THE PROCESS OF SWINGING
AROUND TO A LIGHT S TO SW DIRECTION. AS A RESULT...LAKE EFFECT SNOW
SHOWERS FOR THE TIME BEING HAVE ENDED AT KIWD/KCMX/KSAW...AND VFR
CONDITIONS SHOULD GENERALLY PREVAIL OVERNIGHT. HOWEVER...-SN
ASSOCIATED WITH APPROACHING DISTURBANCE MAY AFFECT KIWD OVERNIGHT
INTO THE MORNING...BRINGING MVFR CONDITIONS. OTHERWISE...FOCUS WILL
SHIFT TO MESOLOW DEVELOPING OVER WRN LAKE SUPERIOR OVERNIGHT. AS THE
LOW SHIFTS INTO WRN UPPER MI THIS AFTN...A PERIOD OF MDT TO
POTENTIALLY HVY SNOW WILL IMPACT KIWD/KCMX AS WINDS SHIFT TO AN
ONSHORE DIRECTION. FOR NOW...INCLUDED IFR CONDITIONS AT BOTH
TERMINALS FOR SEVERAL HRS IN THE AFTN TO EVENING. OCNL LIFR
CONDITIONS NOT OUT OF THE QUESTION. KSAW SHOULD GENERALLY REMAIN VFR
INTO THE AFTN BEFORE WINDS BECOME LIGHT NRLY. MIGHT BE A PERIOD OF
HEAVIER SHSN/LOWER CONDITIONS AT KSAW THIS EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 343 PM EST WED NOV 27 2013
STRONGER N WINDS WILL CONTINUE TO SLOWLY DIMINISH THIS EVENING. A
RIDGE OF HIGH PRESSURE WILL EXTEND OVER LAKE SUPERIOR THIS
EVENING...WHILE A WEAK LOW OVER THE EASTERN DAKOTAS PUSHES ACROSS
THE UPPER GREAT LAKES LATE TONIGHT THROUGH THURSDAY. LARGER HIGH
PRESSURE EXTENDING ACROSS MUCH OF CENTRAL CANADA THROUGH THE CENTRAL
PLAINS THURSDAY AFTERNOON WILL SWING ACROSS THE UPPER GREAT LAKES
THURSDAY NIGHT...BEFORE EXITING TO THE LOWER GREAT LAKES AND NEW
ENGLAND STATES FRIDAY AFTERNOON THROUGH SATURDAY. EXPECT A LOW OVER
LAKE WINNIPEG FRIDAY NIGHT TO PUSH ACROSS SOUTHERN ONTARIO AND LAKE
SUPERIOR SATURDAY AND SATURDAY EVENING. THERE IS THE POTENTIAL FOR
30KT S GUSTS DURING THE DAY SATURDAY. FOR SUNDAY AND MONDAY...HIGH
PRESSURE SCOOTING ACROSS ONTARIO WILL PUSH A RIDGE OVER LAKE
SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
MIZ001.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
529 AM CST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 AM CST THU NOV 28 2013
MAIN ISSUE FOR THE SHORT TERM IS HOW LONG WILL IT TAKE FOR THE
CLOUDS TO CLEAR OUT TODAY. A 1018MB SFC LOW HAS BEEN MAKING SLOW BUT
STEADY PROGRESS ACROSS NRN IOWA OVERNIGHT AND WILL CONTINUE ON A
TRACK TOWARD SRN LAKE MICHIGAN BY THE AFTERNOON. AN INVERTED SFC
TROUGH HAS BEEN WORKING EAST ACROSS MN IN CONCERT WITH THE IOWA LOW
AND HAS HELPED MAINTAIN THE STRATUS NORTH OF THE LOW. BEHIND THIS
INVERTED TROUGH...ANOTHER CANADIAN HIGH IS BUILDING SOUTH ACROSS THE
DAKOTAS. RH TIME-HEIGHT PROFILES SHOW PLENTY OF DRYING AND
SUBSIDENCE OCCURRING AS THIS HIGH MOVES IN...WHICH IS WHY THE
QUESTION WITH THE CLOUDS IS HOW LONG DO THEY STICK AROUND. FOR
NOW...HAVE A RATHER CLOUDY FORECAST THROUGH 18Z...BUT QUICKLY START
TO IMPROVE THINGS FROM WEST TO EAST THIS AFTERNOON...IN LINE WITH
WHAT THE RAP 925-850 MB RH SHOWS.
ALTHOUGH THERE IS CURRENTLY A SEA OF LIGHT SNOW REPORTS ACROSS NRN
MN AND NODAK...THESE ARE NOT EXPECTED TO MAKE IT INTO THE MPX AREA.
THE REASON FOR THIS IS THAT SFC TEMPERATURES WHERE THE SNOW IS BEING
REPORTED RIGHT NOW ARE ALL IN THE LOW TO MID TEENS...WHICH MEANS UP
THERE...THE DENDRITIC GROWTH ZONE IS DOWN AT THE SURFACE AND EXTENDS
UP THROUGH THE CLOUD LAYER. ADD IN THE WEAK LIFT ALONG/AHEAD OF THE
INVERTED TROUGH WITH A DGZ ALL THE WAY DOWN TO THE SURFACE AND YOU
END UP WITH THE SCENARIO WHERE ALL CLOUDS HAVE SNOW. COMING DOWN TO
CENTRAL/SRN MN...SFC TEMPS DOWN HERE ARE ALL IN THE UPPER
TEENS/LOWER 20S...OUTSIDE OF THE DGZ. THE SHALLOWER DGZ THAT DOES
NOT EXTEND TO THE SFC HAS ALLOWED THE CLOUDS DOWN HERE TO REMAIN
SNOW FREE. CAA AT THE MOMENT IS NOT STRONG ENOUGH TO COOL OUR SFC
TEMPS DOWN INTO THE DGZ BEFORE WE START GETTING SOME SOLAR
HEATING...SO DO NOT ANTICIPATE THE SNOW/FLURRY REPORTS TO MAKE IT
MUCH FARTHER SOUTH THAN THEY CURRENTLY ARE.
THE COMBINATION OF WEAK CAA AND CLOUD COVER WILL AGAIN LIMIT THE
DIURNAL TEMPERATURE INCREASE AGAIN TODAY...WITH TEMPERATURES THIS
AFTERNOON ONLY EXPECTED TO INCREASE ABOUT 5 OR 10 DEGREES ABOVE
THEIR CURRENT VALUES THIS MORNING. TONIGHT...YET ANOTHER SFC RIDGE
AXIS WILL BE CENTERED ACROSS THE AREA...RESULTING IN ANOTHER NIGHT
WITH LOWS IN THE SINGLE DIGITS TO LOWER TEENS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 250 AM CST THU NOV 28 2013
THE LONG TERM WILL BEGIN TRANQUIL BUT WILL LIKELY END RATHER
ACTIVE AS A MAJOR PATTERN SHIFT UNFOLDS. HIGH PRESSURE OVER THE
GREAT LAKES WILL SLIDE EAST FRIDAY WITH WAA COMMENCING AT THE
START OF THE PERIOD. BREEZY SOUTHEAST WINDS WILL BRING HIGHS BACK
TO WHERE THEY SHOULD BE IN THE UPPER 20S TO MID 30S.
A WEAK CLIPPER SYSTEM WILL DIVE SOUTHEAST ACROSS NORTHERN LAKE
SUPERIOR FRIDAY NIGHT AND EARLY SATURDAY. FORECAST SOUNDINGS SHOW
SUFFICIENT MOISTENING IN THE LOWER LEVELS AFTER MIDNIGHT TO
SUPPORT A CHANCE OF FREEZING DRIZZLE OR FLURRIES OVER WESTERN
WISCONSIN. HOWEVER...KEPT PROBABILITIES RATHER LOW DUE TO THE
SOURCE REGION OF THIS MOISTURE BEING FROM THE SPRAWLING EASTERN
CONUS HIGH PRESSURE SYSTEM THAT DROVE A COLD FRONT THROUGH THE
GULF AND CUBA. NEEDLESS TO SAY...NOT A WHOLE LOT OF MOISTURE TO BE
FOUND ANYWHERE NEARBY.
SURFACE RIDGING WILL RETURN SATURDAY AND SUNDAY WITH TEMPERATURES
REMAINING NEAR NORMAL. MEANWHILE...A POTENT UPPER LOW TRAVERSING
ALASKA WILL DIVE SOUTHEAST ALONG THE BRITISH COLOMBIAN COAST INTO
THE PACIFIC NORTHWEST AND THE CENTRAL ROCKIES BY THE MIDDLE OF
NEXT WEEK. THIS WILL BE REPLACED WITH A 570DM RIDGE OVER ALASKA
MONDAY AND BUILDING HEIGHTS ACROSS THE CENTRAL AND EASTERN CONUS
FOR LATE WEEK. A SIZABLE CHUNK OF ARCTIC AIR WILL DISLODGE FROM
THE POLAR VORTEX AND SINK SOUTH TOWARD THE NORTHERN CONUS BY LATE
IN THE LONG TERM. FOLLOWED THE ECMWF/GEM/GFS ENSEMBLE SOLUTION
WITH A MORE ZONAL LOOK ACROSS THE NORTHERN TIER OF STATES AS
OPPOSED TO THE OPERATIONAL GFS WHICH SEEMED TOO AMPLIFIED DURING MID
TO LATE WEEK.
SOUTHERLY FLOW AHEAD OF THE WESTERN TROUGH AND MODEST ISENTROPIC
LIFT IN THE PRESENCE OF INCREASING MID LEVEL MOISTURE LOOKS
INCREASINGLY LIKELY WILL ALLOW FOR PERIODS OF LIGHT SNOW ALONG AN
EAST-WEST STATIONARY BOUNDARY FROM SUNDAY NIGHT THROUGH TUESDAY
NIGHT. DUE TO A SURFACE HIGH ANCHORED TO THE NORTH...EASTERLY
SURFACE FLOW WILL BRING A CONTINUED SUPPLY OF DRY BOUNDARY LAYER
AIR AND THUS AMOUNTS WILL BE LIGHT DURING THIS PERIOD.
SURFACE LOW ORGANIZING TO THE LEE OF THE ROCKIES IN ADVANCE OF
THE ROCKIES TROUGH MAY EJECT NORTHEAST TOWARD THE GREAT LAKES IN
THE WEDNESDAY NIGHT/THURSDAY TIMEFRAME. ECMWF BRINGS A PRETTY
IMPRESSIVE SYSTEM THROUGH WITH SIGNIFICANT ACCUMULATING SNOW. GEM
IS A BIT FURTHER SOUTH. REGARDLESS...FOLLOWING THIS POTENTIAL
STORM WILL BE AN EXPANSIVE INTRUSION OF ARCTIC AIR FOR MOST OF THE
CENTRAL AND WESTERN CONUS. THIS SIGNAL HAS BEEN SOLID IN CLIMATE
FORECASTING MODELS FOR WEEKS NOW AND AS CPC POINTS OUT IN THEIR
6-10 AND 8-14 DAY OUTLOOKS...PROBABILITY OF OCCUR RANCE IS VERY
HIGH. IF WE CAN GET A SNOWPACK DOWN BEFORE THIS ARRIVES...TEMPS
COULD BE 20-30+ DEGREES BELOW AVERAGE FOR EARLY DECEMBER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 519 AM CST THU NOV 28 2013
HIGH PRESSURE WILL BE MOVING ACROSS THE TERMINALS THIS
PERIOD...RESULTING IN YET ANOTHER QUIET TAF PERIOD. MAIN ISSUE FOR
TODAY IS WHEN WILL THE VFR STRATUS CLEAR. ALREADY SEEING SOME
CLEARING DEVELOP NORTH OF FARGO...AND RAP 925-850 MB RH SHOWS
CLEARING DEVELOPING FROM THIS AREA QUICKLY AFTER 15Z OR SO.
CURRENT TAFS LOOKED TO HAVE THINGS TIMED WELL WITH RESPECT TO
CLEARING SO MADE FEW CHANGES. WILL SEE NW WINDS TODAY THAT WILL GO
CALM OVERNIGHT WITH THE HIGH AS SE WINDS RETURN LATE AT MN
TERMINALS.
KMSP...ABOUT THE ONLY POSSIBLE DEVIATION THAT COULD BE SEEN FROM
CURRENT TAF WOULD BE A LATER SCATTERING OUT OF VFR CIGS THAN
CURRENTLY INDICATED...BUT AT 5K FT...THEY WILL BE OF MINIMAL IMPACT.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS SE AT 5-10KTS.
SAT...VFR. SW WINDS AT 5-10KTS BECOMING W/NW DURING THE AFT/EVE.
SUN...VFR. WINDS E/SE AT 5KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...BORGHOFF
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
414 AM CST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 AM CST THU NOV 28 2013
MAIN ISSUE FOR THE SHORT TERM IS HOW LONG WILL IT TAKE FOR THE
CLOUDS TO CLEAR OUT TODAY. A 1018MB SFC LOW HAS BEEN MAKING SLOW BUT
STEADY PROGRESS ACROSS NRN IOWA OVERNIGHT AND WILL CONTINUE ON A
TRACK TOWARD SRN LAKE MICHIGAN BY THE AFTERNOON. AN INVERTED SFC
TROUGH HAS BEEN WORKING EAST ACROSS MN IN CONCERT WITH THE IOWA LOW
AND HAS HELPED MAINTAIN THE STRATUS NORTH OF THE LOW. BEHIND THIS
INVERTED TROUGH...ANOTHER CANADIAN HIGH IS BUILDING SOUTH ACROSS THE
DAKOTAS. RH TIME-HEIGHT PROFILES SHOW PLENTY OF DRYING AND
SUBSIDENCE OCCURRING AS THIS HIGH MOVES IN...WHICH IS WHY THE
QUESTION WITH THE CLOUDS IS HOW LONG DO THEY STICK AROUND. FOR
NOW...HAVE A RATHER CLOUDY FORECAST THROUGH 18Z...BUT QUICKLY START
TO IMPROVE THINGS FROM WEST TO EAST THIS AFTERNOON...IN LINE WITH
WHAT THE RAP 925-850 MB RH SHOWS.
ALTHOUGH THERE IS CURRENTLY A SEA OF LIGHT SNOW REPORTS ACROSS NRN
MN AND NODAK...THESE ARE NOT EXPECTED TO MAKE IT INTO THE MPX AREA.
THE REASON FOR THIS IS THAT SFC TEMPERATURES WHERE THE SNOW IS BEING
REPORTED RIGHT NOW ARE ALL IN THE LOW TO MID TEENS...WHICH MEANS UP
THERE...THE DENDRITIC GROWTH ZONE IS DOWN AT THE SURFACE AND EXTENDS
UP THROUGH THE CLOUD LAYER. ADD IN THE WEAK LIFT ALONG/AHEAD OF THE
INVERTED TROUGH WITH A DGZ ALL THE WAY DOWN TO THE SURFACE AND YOU
END UP WITH THE SCENARIO WHERE ALL CLOUDS HAVE SNOW. COMING DOWN TO
CENTRAL/SRN MN...SFC TEMPS DOWN HERE ARE ALL IN THE UPPER
TEENS/LOWER 20S...OUTSIDE OF THE DGZ. THE SHALLOWER DGZ THAT DOES
NOT EXTEND TO THE SFC HAS ALLOWED THE CLOUDS DOWN HERE TO REMAIN
SNOW FREE. CAA AT THE MOMENT IS NOT STRONG ENOUGH TO COOL OUR SFC
TEMPS DOWN INTO THE DGZ BEFORE WE START GETTING SOME SOLAR
HEATING...SO DO NOT ANTICIPATE THE SNOW/FLURRY REPORTS TO MAKE IT
MUCH FARTHER SOUTH THAN THEY CURRENTLY ARE.
THE COMBINATION OF WEAK CAA AND CLOUD COVER WILL AGAIN LIMIT THE
DIURNAL TEMPERATURE INCREASE AGAIN TODAY...WITH TEMPERATURES THIS
AFTERNOON ONLY EXPECTED TO INCREASE ABOUT 5 OR 10 DEGREES ABOVE
THEIR CURRENT VALUES THIS MORNING. TONIGHT...YET ANOTHER SFC RIDGE
AXIS WILL BE CENTERED ACROSS THE AREA...RESULTING IN ANOTHER NIGHT
WITH LOWS IN THE SINGLE DIGITS TO LOWER TEENS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 250 AM CST THU NOV 28 2013
THE LONG TERM WILL BEGIN TRANQUIL BUT WILL LIKELY END RATHER
ACTIVE AS A MAJOR PATTERN SHIFT UNFOLDS. HIGH PRESSURE OVER THE
GREAT LAKES WILL SLIDE EAST FRIDAY WITH WAA COMMENCING AT THE
START OF THE PERIOD. BREEZY SOUTHEAST WINDS WILL BRING HIGHS BACK
TO WHERE THEY SHOULD BE IN THE UPPER 20S TO MID 30S.
A WEAK CLIPPER SYSTEM WILL DIVE SOUTHEAST ACROSS NORTHERN LAKE
SUPERIOR FRIDAY NIGHT AND EARLY SATURDAY. FORECAST SOUNDINGS SHOW
SUFFICIENT MOISTENING IN THE LOWER LEVELS AFTER MIDNIGHT TO
SUPPORT A CHANCE OF FREEZING DRIZZLE OR FLURRIES OVER WESTERN
WISCONSIN. HOWEVER...KEPT PROBABILITIES RATHER LOW DUE TO THE
SOURCE REGION OF THIS MOISTURE BEING FROM THE SPRAWLING EASTERN
CONUS HIGH PRESSURE SYSTEM THAT DROVE A COLD FRONT THROUGH THE
GULF AND CUBA. NEEDLESS TO SAY...NOT A WHOLE LOT OF MOISTURE TO BE
FOUND ANYWHERE NEARBY.
SURFACE RIDGING WILL RETURN SATURDAY AND SUNDAY WITH TEMPERATURES
REMAINING NEAR NORMAL. MEANWHILE...A POTENT UPPER LOW TRAVERSING
ALASKA WILL DIVE SOUTHEAST ALONG THE BRITISH COLOMBIAN COAST INTO
THE PACIFIC NORTHWEST AND THE CENTRAL ROCKIES BY THE MIDDLE OF
NEXT WEEK. THIS WILL BE REPLACED WITH A 570DM RIDGE OVER ALASKA
MONDAY AND BUILDING HEIGHTS ACROSS THE CENTRAL AND EASTERN CONUS
FOR LATE WEEK. A SIZABLE CHUNK OF ARCTIC AIR WILL DISLODGE FROM
THE POLAR VORTEX AND SINK SOUTH TOWARD THE NORTHERN CONUS BY LATE
IN THE LONG TERM. FOLLOWED THE ECMWF/GEM/GFS ENSEMBLE SOLUTION
WITH A MORE ZONAL LOOK ACROSS THE NORTHERN TIER OF STATES AS
OPPOSED TO THE OPERATIONAL GFS WHICH SEEMED TOO AMPLIFIED DURING MID
TO LATE WEEK.
SOUTHERLY FLOW AHEAD OF THE WESTERN TROUGH AND MODEST ISENTROPIC
LIFT IN THE PRESENCE OF INCREASING MID LEVEL MOISTURE LOOKS
INCREASINGLY LIKELY WILL ALLOW FOR PERIODS OF LIGHT SNOW ALONG AN
EAST-WEST STATIONARY BOUNDARY FROM SUNDAY NIGHT THROUGH TUESDAY
NIGHT. DUE TO A SURFACE HIGH ANCHORED TO THE NORTH...EASTERLY
SURFACE FLOW WILL BRING A CONTINUED SUPPLY OF DRY BOUNDARY LAYER
AIR AND THUS AMOUNTS WILL BE LIGHT DURING THIS PERIOD.
SURFACE LOW ORGANIZING TO THE LEE OF THE ROCKIES IN ADVANCE OF
THE ROCKIES TROUGH MAY EJECT NORTHEAST TOWARD THE GREAT LAKES IN
THE WEDNESDAY NIGHT/THURSDAY TIMEFRAME. ECMWF BRINGS A PRETTY
IMPRESSIVE SYSTEM THROUGH WITH SIGNIFICANT ACCUMULATING SNOW. GEM
IS A BIT FURTHER SOUTH. REGARDLESS...FOLLOWING THIS POTENTIAL
STORM WILL BE AN EXPANSIVE INTRUSION OF ARCTIC AIR FOR MOST OF THE
CENTRAL AND WESTERN CONUS. THIS SIGNAL HAS BEEN SOLID IN CLIMATE
FORECASTING MODELS FOR WEEKS NOW AND AS CPC POINTS OUT IN THEIR
6-10 AND 8-14 DAY OUTLOOKS...PROBABILITY OF OCCUR RANCE IS VERY
HIGH. IF WE CAN GET A SNOWPACK DOWN BEFORE THIS ARRIVES...TEMPS
COULD BE 20-30+ DEGREES BELOW AVERAGE FOR EARLY DECEMBER.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 1025 PM CST WED NOV 27 2013
A BKN-OVC DECK FROM 5KFT-7KFT WILL PREVAIL OVERNIGHT...AS MVFR
LEVEL CLOUDS APPROACH FROM THE NORTH/WEST. SAID CLOUDS ARE
EXPECTED TO ENTER WEST CENTRAL MN /KAXN/ BY DAYBREAK...AND
GRADUALLY SNAKE SOUTH AND EAST /TOWARD KRWF/ DURING THE MORNING.
THE CLOUDS SHOULD BECOME MORE TRANSPARENT DURING THE DAYTIME
HOWEVER...SO HAVE ONLY INCLUDED A SCATTERED GROUP AT KMSP...BUT
KEAU/KRNH LIKELY SEEING BKN-OVC MVFR CIGS THROUGH A GOOD PORTION
OF THE DAY. LIGHT AND VARIABLE WINDS OVERNIGHT BECOME
WEST/NORTHWEST ON THURSDAY AND INCREASE TO 10-15KTS IN THE WAKE OF
THE TROUGH.
KMSP...
A 5000FT CIG WILL PREVAIL INTO THURSDAY...WITH A POSSIBILITY FOR
MVFR LEVEL CLOUDS BETWEEN 18Z THU AND 00Z FRI. HAVE INCLUDED A SCT
MENTION FOR NOW. LIGHT AND VARIABLE WINDS OVERNIGHT SHIFT TO THE
NORTHWEST BY 14Z THURSDAY /AND GUST TO AROUND 15KTS DURING THE
AFTERNOON/.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS SE AT 5-10KTS.
SAT...VFR. SW WINDS AT 5-10KTS BECOMING W/NW DURING THE AFT/EVE.
SUN...VFR WITH MVFR AND -SN POSSIBLE LATE. WINDS E/SE AT 5KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...BORGHOFF
AVIATION...LS
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
554 AM CST Thu Nov 28 2013
.SHORT TERM: (Through Late This Afternoon)
Issued at 327 AM CST Thu Nov 28 2013
Southerly winds ahead of low pressure zipping from N IA into MI
today will bring a brief shot of warm air into the CWA this morning,
which will then be followed by a secondary surge of cold air during
the afternoon and into the evening. Primary question for this
Thanksgiving Day is how warm to go for high temperatures given the
see-saw nature of the temperature advection during the day. Have
followed trend of going forecasts in heading towards the warm side
of guidance, especially along and south of the I-70 corridor in
Missouri where thermal ridge ahead of cold front, mixing, and strong
sunshine should all combine to have their greatest impact. In
northern sections of the CWA it may be that temps will make a fairly
substantial jump this morning, but additional temp climb during the
afternoon will struggle as the return of colder air trumps the
effects of afternoon sunshine.
Have also gone with lots of sunshine today. Will need to keep an eye
on post frontal stratus that is making a strong southward surge into
E NE early today, but if all of the forecast soundings and RH
guidance is to be believed the dry airmass and mixing will cause
this deck to erode before reaching our CWA.
Truett
.LONG TERM: (Tonight through Wednesday)
Issued at 327 AM CST Thu Nov 28 2013
(Tonight through Saturday Night)
Now that the energy along the East Coast has moved offshore, what
is left is a broad low amplitude trough across the ern half of the
country and nw flow along the Canadian border funneling into the ern
trough. There is split flow along the West Coast with a closed low off
the srn CA coast. The NW flow keeps the parade of cold fronts coming
every 48 hrs or so with the most recent bndry exiting the CWA early
this evening. The next short wave and assoc cold front is fcst for
Saturday night. The fronts are passing with such frequency that the
atmosphere does not have much chance to recover. Therefore, there isn`t
much moisture to work with and the fronts pass quietly with no precip
and little to no cloud cover. This front will fail to tap a true arctic
airmass and shouldn`t be anymore than a subtle wind shift. There is
another short wave that is expected to pass thru the area late this
week. The vort max is expected to move across srn MO/IL Friday night
into Saturday morning. Due to limited moisture, no precip is expected
with this feature.
Temps will be slightly cooler on Friday behind the cold front. I generally
used a blend of MOS guidance but, tended to favor the warmer MAV. Temps
are expected to bounce back again on Saturday in advance of the next
cold front. Generally used a blend of guidance but went on the warm
side of guidance across cntrl and e cntrl MO due to the synoptic set
up for a decent warm up.
(Sunday thru Wednesday)
Model consensus agrees that NW flow continues thru Monday and then
transitions to SW flow by Wednesday. The problem is the path they
take from NW to SW flow. Return flow begins Tuesday. The column
eventually moistens sufficiently for clouds and rain chances
beginning Tuesday night and continuing thru Wednesday. Due to model
differences, this is a lower confidence fcst.
Highs are expected to be 5-10 degrees cooler on Sunday after the
Saturday night FROPA. A slow warming trend begins on Monday that
continues thru Wednesday with temps near seasonal norms by Tuesday
and Wednesday.
2%
&&
.AVIATION: (For the 12z TAFs through 12z Friday Morning)
Issued at 550 AM CST Thu Nov 28 2013
Latest RUC data continues to indicate low level jet over the
region early this morning, with southwest winds in the 40-45kt
range. LLWS was introduced to the TAFs several hours ago because
of this, and will continue the LLWS in the 12z TAFs until 15z when
mixing begins to lessen this low level flow.
Surface low pressure is allowing warm air to work into the region
early today on south-southwest winds, but the cold front trailing
the low has now dropped into NW MO. This front will work across
the CWA later this afternoon, and 12z TAFs attempt to reflect the
wind shift associated with the front.
With extremely dry ams forecast in the lower levels of the AMS
over the mid-Mississippi Valley, any cloudiness should be limited
to some patchy high level cirrus. Will need to keep an eye on
stratus dropping across NE and behind the cold front, but all
indications are that these clouds will erode before reaching our CWA.
Specifics for KSTL: Low level wind shear threat should subside
around 15z. Otherwise, it appears favorable flying conditions are
in the offing for the KSTL area, with clouds limited to a bit of
patchy cirrus. Surface winds will slowly veer to the west during
the morning, and then to the northwest this afternoon with the
passage of the aforementioned cold front.
Truett
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
919 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 913 AM CST THU NOV 28 2013
WITH THICK STRATUS EVIDENT ON SATELLITE IMAGERY AND LATEST RAP
COMING IN WITH PESSIMISTIC CONDITIONS FOR THE REST OF THE
DAY...WENT AHEAD AND FURTHER INCREASED CLOUD COVER FROM PREVIOUS
UPDATE AS WELL AS DROPPED FORECAST HIGH TEMPERATURES ABOUT 5
DEGREES ACROSS THE BOARD. OTHERWISE...NO ADDITIONAL CHANGES
NECESSARY AT THIS TIME.
UPDATE ISSUED AT 749 AM CST THU NOV 28 2013
BASED ON LATEST SHORTWAVE IR SATELLITE AND MODEL TRENDS...
ANTICIPATE WE WILL NEED TO MAKE SOME SUBSTANTIAL CHANGES TO THE
FCST TODAY AND POSSIBLY INTO TONIGHT AND TOMORROW. THESE CHANGES
WILL INVOLVE MORE CLOUDS AND COOLER TEMPS...PROBABLY NOT BECOMING
AS WARM AS THOUGHT THE LAST FEW DAYS AND WE SAW THIS AS A
POTENTIAL OPTION EARLIER THIS WEEK. IT/S TOUGH TO FCST FAR IN
ADVANCE THOUGH.
THERE IS AN EXTENSIVE BANK OF STRATUS RACING S TO THE KS-NEB
BORDER AT THIS TIME AND IT EXTENDS ALL THE WAY UP INTO THE
CANADIAN PRAIRIES. BELIEVE THIS IS GOING TO BE A FCST PROBLEM THRU
SUNSET TOMORROW AS IT WILL BE STUCK IN A THERMAL TROF /COLD
POCKET/ AND WILL RESIST EROSION. WE REALLY NEED WARM AIR ADVECTION
TO GET RID OF IT AND THAT WILL NOT HAPPEN UNTIL LATE TONIGHT OR
TOMORROW.
SO THE FCST SKY HAS BEEN TURNED SIGNIFICANTLY MORE PESSIMISTIC
THRU MIDDAY AND EXPECT WE WILL NEED TO PUSH THIS FURTHER INTO THE
AFTERNOON PENDING THE LATEST SATELLITE TRENDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST THU NOV 28 2013
OVERNIGHT UPPER AIR ANALYSIS INDICATES MID TO UPPER LEVEL
TROUGHING OVER THE EASTERN CONUS...WITH A RIDGE OVER THE WEST AND
A MID LEVEL LOW OVER THE PACIFIC OFF THE CALIFORNIA COAST. A
SUBTLE MID LEVEL PERTURBATION IS ALSO NOTED OVER SOUTHERN
MINNESOTA...MOVING SOUTHEAST. MID TO UPPER LEVEL JET ENERGY
EXTENDS FROM SOUTH CENTRAL CANADA...SOUTHEAST INTO THE CENTRAL
CONUS...AND FINALLY EAST AND NORTHEAST ALONG THE EASTERN CONUS
INTO SOUTHEASTERN CANADA. MID TO UPPER LEVEL FLOW OVER OUR AREA
MAXES OUT AT AROUND 70KTS BETWEEN 300MB AND 200MB PER 00Z SOUNDING
DATA FROM KLBF AND KOAX. WATER VAPOR IMAGERY INDICATES INCREASED
VALUES OF MID LEVEL MOISTURE EXTENDING ALONG THE BACK SIDE OF THE
WEST COAST RIDGE...AS WELL AS FROM THE PACIFIC EASTWARD INTO
MEXICO AND THE SOUTHERN PLAINS. MID LEVEL MOISTURE OVER OUR AREA
HOWEVER REMAINS FAIRLY LIMITED. AT THE SURFACE...AN AREA OF LOW
BAROMETRIC PRESSURE EXISTS OVER NORTHWEST IOWA JUST AHEAD OF THE
AFOREMENTIONED MID LEVEL PERTURBATION...WITH AN ASSOCIATED COLD
FRONT EXTENDING FROM WESTERN IOWA INTO SOUTHEASTERN NEBRASKA AND
NORTHERN KANSAS. THIS FRONT HAS CLEARED MOST ALL OF OUR CWA AND AS
A RESULT...THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM
THE NORTH/NORTHWEST.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST NORTHWESTERLY MID TO UPPER LEVEL FLOW WILL PERSIST OVER
OUR AREA THROUGH THE NEXT 24 HOURS AS THE EASTERN CONUS TROUGH AND
WESTERN CONUS RIDGE BOTH TREK EAST. THE MID LEVEL
PERTURBATION...CURRENTLY OVER SOUTHERN MINNESOTA...IS EXPECTED TO
CONTINUE MOVING SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH NO
OTHER MID LEVEL SHORTWAVES/PERTURBATIONS EXPECTED TO IMPACT THE
REGION. AT THE SURFACE...THE AREA OF LOW BAROMETRIC
PRESSURE...CURRENTLY OVER NORTHWEST IOWA...SHOULD ALSO CONTINUE
MOVING TO THE EAST/SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH THE
ASSOCIATED LOW LEVEL BAROCLINIC ZONE PUSHING FARTHER
SOUTH/SOUTHEAST ACROSS THE PLAINS. THE LOW LEVEL WIND FIELD ACROSS
OUR AREA SHOULD REMAIN FROM THE NORTH/NORTHWEST THROUGH MUCH OF
TODAY AS A RESULT. THAT BEING SAID...GUIDANCE SUGGESTS THE PASSAGE
OF A SURFACE RIDGE TO EAST SHOULD ALLOW FOR LOW LEVEL RETURN FLOW
ACROSS OUR AREA DURING THE OVERNIGHT HOURS TONIGHT.
WITH AN OVERALL LACK IN OMEGA EXPECTED OVER OUR AREA...DRY
CONDITIONS ARE CURRENTLY FORECAST THROUGH THE NEXT 24 HOURS.
SATELLITE IMAGERY INDICATES A BAND OF STRATUS OVER MUCH OF THE
NORTHERN PLAINS THIS MORNING AND THIS STRATUS IS ADVANCING TO THE
SOUTH...ABOUT 150 MILES NORTH OF THE AFOREMENTIONED SURFACE FRONT.
GUIDANCE FROM THE NAM AND RAP BOTH SHOW THIS STRATUS...WITH HIGH
RELATIVE HUMIDITY VALUES AT 925MB NOTED ON PLAN VIEW
MAPS...INFILTRATING OUR NORTH/NORTHEASTERN CWA JUST PRIOR TO
SUNRISE THIS MORNING...BUT DISSIPATING POST-SUNRISE AS DIABATIC
HEATING RESULTS IN INCREASED BOUNDARY LAYER HEIGHT AND MIXING.
WENT AHEAD AND PLAYED PRETTY CLOSE TO NAM AND RAP GUIDANCE FOR THE
CLOUD FORECAST THROUGH THE FIRST PART OF THE SHORT TERM FORECAST
PERIOD...WITH THIS STRATUS EXPECTED TO IMPACT OUR NORTH/NORTHEAST
BY 10Z OR 11Z THIS MORNING...AND THEN DISSIPATE BY 15Z OR 16Z.
WITH LOW LEVEL RETURN FLOW INFILTRATING THE REGION TONIGHT...THERE
ARE INDICATIONS OF ISENTROPIC UPGLIDE AND SATURATION...PRIMARILY
ALONG THE 275-285K SURFACES...OVER THE HIGH PLAINS OF KANSAS AND
NEBRASKA. ALTHOUGH IT APPEARS MUCH OF OUR CWA SHOULD BE SPARED
FROM ANY STRATUS DEVELOPMENT THROUGH 12Z FRIDAY...925MB RELATIVE
HUMIDITY PLAN VIEW MAPS FROM THE NAM...OPERATIONAL GFS AND EC ALL
SUGGEST OUR EXTREME WEST/SOUTHWEST COULD ACTUALLY OBSERVE QUITE A
BIT OF CLOUD COVER TOWARDS SUNRISE FRIDAY AS THE EASTERN PERIPHERY
OF THE HIGH PLAINS STRATUS CLIPS THE AREA. WENT AHEAD WITH A
BROKEN CEILING ACROSS OUR EXTREME WEST/SOUTHWEST BY 12Z FRIDAY AS
A RESULT.
THE INTRUSION OF A COOLER LOW LEVEL AIRMASS BEHIND THE LOW LEVEL
BAROCLINIC ZONE SHOULD RESULT IN A COOLER DAY TODAY WHEN COMPARED
TO WEDNESDAY. HIGH TEMPERATURES GENERALLY IN THE MID 30S ACROSS
OUR NORTH...AND INTO THE MID 40S ACROSS OUR SOUTH...ARE FORECAST
FOR TODAY AS A RESULT. IT MIGHT OTHERWISE BE REASONABLE TO THINK
TONIGHT WILL BE COOLER WHEN COMPARED TO EARLY THIS MORNING...BUT
WITH LOW LEVEL RETURN FLOW EXPECTED TO INFILTRATE OUR AREA DURING
THE OVERNIGHT HOURS...OVERNIGHT LOWS TONIGHT SHOULD ACTUALLY BE
PRETTY CLOSE TO WHAT WE ARE EXPECTING EARLY THIS MORNING.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CST THU NOV 28 2013
THE FIRST PART OF THE LONG TERM FORECAST IS DRY WITH ABOVE NORMAL
TEMPERATURES...AFTERWHICH A MORE UNSETTLED...COLDER AND MORE
CHALLENGING FORECAST TAKES HOLD BY MID NEXT WEEK.
A TRANSITIONING WEST/NORTHWEST UPPER LEVEL FLOW WILL KEEP THE
REGION MAINLY DRY AND MILD THROUGH THROUGH THE REMAINDER OF THE
HOLIDAY WEEKEND. REGIONAL TRAVEL CONCERNS WILL BE NIL...AND BOTH
DAYTIME HIGHS AND NIGHTTIME LOWS WILL BE AT OR SLIGHTLY ABOVE
SEASONAL NORMALS. ONE NOTABLE WEATHER ELEMENT WILL THE WIND...OR
LACK THERE OF ON SATURDAY AND SUNDAY. THAT WILL HELP OFFSET ANY
COOLING FROM PASSING CLOUDS THROUGHOUT THE WEEKEND.
OVERALL...PRETTY NICE FOR THE END OF NOVEMBER. WARM ADVECTION
ASSOCIATED WITH WAVE ACROSS THE NORTHERN PLAINS SUNDAY WILL
THICKEN CLOUDS...BUT NOT TOO EXCITED ABOUT INCURRING ANY
MEASURABLE PRECIPITATION AT THIS POINT.
ACTUALLY THE MILD WEATHER WILL CONTINUE INTO THE FIRST PART OF
NEXT WEEK...ALTHOUGH THINGS WILL BE CHANGING AS UPPER LEVEL
HEIGHTS LOWER AND WE START TO SEE UPPER LEVEL LOW PRESSURE DEEPEN
IN THE GREAT BASIN REGION. AS THE LOW STRENGTHENS...AN INCREASING
SOUTH TO SOUTHEAST FLOW ACROSS THE CENTRAL/SOUTHERN PLAINS
DEVELOPS WHICH WILL KEEP TEMPERATURES ON THE MILD SIDE
MONDAY/TUESDAY. THERE IS SOME MODEL LIKENESS IN OVERALL
TRENDS...BUT VERY UNEASY IN TRYING TO PIN DOWN ANY SPECIFIC
DETAILS FOR NEXT WEEKS FORECAST AT THIS POINT. WE HAVE BEEN
ANTICIPATING A COLD AIR PUSH NEXT WEEK...AND THAT STILL LOOKS ON
TRACK FOR ABOUT WEDNESDAY...BUT THE COLD AIR PLUNGE COMES IN
PIECES WITH THE COLDEST AIR NOT LIKELY TO MAKE IT INTO THE AREA
UNTIL LATER NEXT WEEK. MODELS SUGGEST HEAVIEST PRECIPITATION
TRENDS WILL LIKELY BE ACROSS THE DAKOTAS AT THIS POINT...WITH ONLY
SMALL CHANCES FOR RAIN OR RAIN/SNOW MIX IN THE FORECAST AT THIS
POINT AS THE SYSTEM APPROACHES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 530 AM CST THU NOV 28 2013
MVFR CONDITIONS EXPECTED TO START THE TAF PERIOD...WITH VFR
CONDITIONS EXPECTED 15Z AND BEYOND.
AN AREA OF STRATUS HAS BEEN MOVING SOUTH FROM SOUTH DAKOTA ALL
NIGHT AND IS NOW MOVING INTO THE GRI AREA. THE CEILING WITHIN THIS
STRATUS GENERALLY RANGES BETWEEN 1000FT AND 1500FT AGL...THUS THE
MVFR FORECAST 12-15Z. GUIDANCE CONTINUES TO SUGGEST THIS STRATUS
WILL LIFT AND BREAK APART AFTER SUNRISE AS INCREASING DIABATIC
HEATING ALLOWS FOR INCREASING BOUNDARY LAYER DEPTH AND MIXING. VFR
CONDITIONS ARE CURRENTLY EXPECTED TO BE RESTORED BY 15Z...BUT THIS
WILL NEED TO BE MONITORED THROUGH THE NEXT FEW HOURS FOR POSSIBLE
UPDATES TO THE TAF. THE SURFACE WIND WILL REMAIN FROM THE
NORTH/NORTHEAST TODAY...SUSTAINED AT AROUND 10KTS. THE PASSAGE OF
A SURFACE RIDGE WILL THEN ALLOW FOR A WEAK...NO GREATER THAN
6KTS...SOUTHEASTERLY LOW LEVEL WIND FIELD OVERNIGHT TONIGHT.
VISIBILITY RESTRICTION IS NOT EXPECTED AT GRI THROUGH THE NEXT 24
HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...ROSSI
SHORT TERM...NOAA/NWS/BRYANT
LONG TERM...NOAA/NWS/MORITZ
AVIATION...NOAA/NWS/BRYANT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
749 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 749 AM CST THU NOV 28 2013
BASED ON LATEST SHORTWAVE IR SATELLITE AND MODEL TRENDS...
ANTICIPATE WE WILL NEED TO MAKE SOME SUBSTANTIAL CHANGES TO THE
FCST TODAY AND POSSIBLY INTO TONIGHT AND TOMORROW. THESE CHANGES
WILL INVOLVE MORE CLOUDS AND COOLER TEMPS...PROBABLY NOT BECOMING
AS WARM AS THOUGHT THE LAST FEW DAYS AND WE SAW THIS AS A
POTENTIAL OPTION EARLIER THIS WEEK. IT/S TOUGH TO FCST FAR IN
ADVANCE THOUGH.
THERE IS AN EXTENSIVE BANK OF STRATUS RACING S TO THE KS-NEB
BORDER AT THIS TIME AND IT EXTENDS ALL THE WAY UP INTO THE
CANADIAN PRAIRIES. BELIEVE THIS IS GOING TO BE A FCST PROBLEM THRU
SUNSET TOMORROW AS IT WILL BE STUCK IN A THERMAL TROF /COLD
POCKET/ AND WILL RESIST EROSION. WE REALLY NEED WARM AIR ADVECTION
TO GET RID OF IT AND THAT WILL NOT HAPPEN UNTIL LATE TONIGHT OR
TOMORROW.
SO THE FCST SKY HAS BEEN TURNED SIGNIFICANTLY MORE PESSIMISTIC
THRU MIDDAY AND EXPECT WE WILL NEED TO PUSH THIS FURTHER INTO THE
AFTERNOON PENDING THE LATEST SATELLITE TRENDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST THU NOV 28 2013
OVERNIGHT UPPER AIR ANALYSIS INDICATES MID TO UPPER LEVEL
TROUGHING OVER THE EASTERN CONUS...WITH A RIDGE OVER THE WEST AND
A MID LEVEL LOW OVER THE PACIFIC OFF THE CALIFORNIA COAST. A
SUBTLE MID LEVEL PERTURBATION IS ALSO NOTED OVER SOUTHERN
MINNESOTA...MOVING SOUTHEAST. MID TO UPPER LEVEL JET ENERGY
EXTENDS FROM SOUTH CENTRAL CANADA...SOUTHEAST INTO THE CENTRAL
CONUS...AND FINALLY EAST AND NORTHEAST ALONG THE EASTERN CONUS
INTO SOUTHEASTERN CANADA. MID TO UPPER LEVEL FLOW OVER OUR AREA
MAXES OUT AT AROUND 70KTS BETWEEN 300MB AND 200MB PER 00Z SOUNDING
DATA FROM KLBF AND KOAX. WATER VAPOR IMAGERY INDICATES INCREASED
VALUES OF MID LEVEL MOISTURE EXTENDING ALONG THE BACK SIDE OF THE
WEST COAST RIDGE...AS WELL AS FROM THE PACIFIC EASTWARD INTO
MEXICO AND THE SOUTHERN PLAINS. MID LEVEL MOISTURE OVER OUR AREA
HOWEVER REMAINS FAIRLY LIMITED. AT THE SURFACE...AN AREA OF LOW
BAROMETRIC PRESSURE EXISTS OVER NORTHWEST IOWA JUST AHEAD OF THE
AFOREMENTIONED MID LEVEL PERTURBATION...WITH AN ASSOCIATED COLD
FRONT EXTENDING FROM WESTERN IOWA INTO SOUTHEASTERN NEBRASKA AND
NORTHERN KANSAS. THIS FRONT HAS CLEARED MOST ALL OF OUR CWA AND AS
A RESULT...THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM
THE NORTH/NORTHWEST.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST NORTHWESTERLY MID TO UPPER LEVEL FLOW WILL PERSIST OVER
OUR AREA THROUGH THE NEXT 24 HOURS AS THE EASTERN CONUS TROUGH AND
WESTERN CONUS RIDGE BOTH TREK EAST. THE MID LEVEL
PERTURBATION...CURRENTLY OVER SOUTHERN MINNESOTA...IS EXPECTED TO
CONTINUE MOVING SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH NO
OTHER MID LEVEL SHORTWAVES/PERTURBATIONS EXPECTED TO IMPACT THE
REGION. AT THE SURFACE...THE AREA OF LOW BAROMETRIC
PRESSURE...CURRENTLY OVER NORTHWEST IOWA...SHOULD ALSO CONTINUE
MOVING TO THE EAST/SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH THE
ASSOCIATED LOW LEVEL BAROCLINIC ZONE PUSHING FARTHER
SOUTH/SOUTHEAST ACROSS THE PLAINS. THE LOW LEVEL WIND FIELD ACROSS
OUR AREA SHOULD REMAIN FROM THE NORTH/NORTHWEST THROUGH MUCH OF
TODAY AS A RESULT. THAT BEING SAID...GUIDANCE SUGGESTS THE PASSAGE
OF A SURFACE RIDGE TO EAST SHOULD ALLOW FOR LOW LEVEL RETURN FLOW
ACROSS OUR AREA DURING THE OVERNIGHT HOURS TONIGHT.
WITH AN OVERALL LACK IN OMEGA EXPECTED OVER OUR AREA...DRY
CONDITIONS ARE CURRENTLY FORECAST THROUGH THE NEXT 24 HOURS.
SATELLITE IMAGERY INDICATES A BAND OF STRATUS OVER MUCH OF THE
NORTHERN PLAINS THIS MORNING AND THIS STRATUS IS ADVANCING TO THE
SOUTH...ABOUT 150 MILES NORTH OF THE AFOREMENTIONED SURFACE FRONT.
GUIDANCE FROM THE NAM AND RAP BOTH SHOW THIS STRATUS...WITH HIGH
RELATIVE HUMIDITY VALUES AT 925MB NOTED ON PLAN VIEW
MAPS...INFILTRATING OUR NORTH/NORTHEASTERN CWA JUST PRIOR TO
SUNRISE THIS MORNING...BUT DISSIPATING POST-SUNRISE AS DIABATIC
HEATING RESULTS IN INCREASED BOUNDARY LAYER HEIGHT AND MIXING.
WENT AHEAD AND PLAYED PRETTY CLOSE TO NAM AND RAP GUIDANCE FOR THE
CLOUD FORECAST THROUGH THE FIRST PART OF THE SHORT TERM FORECAST
PERIOD...WITH THIS STRATUS EXPECTED TO IMPACT OUR NORTH/NORTHEAST
BY 10Z OR 11Z THIS MORNING...AND THEN DISSIPATE BY 15Z OR 16Z.
WITH LOW LEVEL RETURN FLOW INFILTRATING THE REGION TONIGHT...THERE
ARE INDICATIONS OF ISENTROPIC UPGLIDE AND SATURATION...PRIMARILY
ALONG THE 275-285K SURFACES...OVER THE HIGH PLAINS OF KANSAS AND
NEBRASKA. ALTHOUGH IT APPEARS MUCH OF OUR CWA SHOULD BE SPARED
FROM ANY STRATUS DEVELOPMENT THROUGH 12Z FRIDAY...925MB RELATIVE
HUMIDITY PLAN VIEW MAPS FROM THE NAM...OPERATIONAL GFS AND EC ALL
SUGGEST OUR EXTREME WEST/SOUTHWEST COULD ACTUALLY OBSERVE QUITE A
BIT OF CLOUD COVER TOWARDS SUNRISE FRIDAY AS THE EASTERN PERIPHERY
OF THE HIGH PLAINS STRATUS CLIPS THE AREA. WENT AHEAD WITH A
BROKEN CEILING ACROSS OUR EXTREME WEST/SOUTHWEST BY 12Z FRIDAY AS
A RESULT.
THE INTRUSION OF A COOLER LOW LEVEL AIRMASS BEHIND THE LOW LEVEL
BAROCLINIC ZONE SHOULD RESULT IN A COOLER DAY TODAY WHEN COMPARED
TO WEDNESDAY. HIGH TEMPERATURES GENERALLY IN THE MID 30S ACROSS
OUR NORTH...AND INTO THE MID 40S ACROSS OUR SOUTH...ARE FORECAST
FOR TODAY AS A RESULT. IT MIGHT OTHERWISE BE REASONABLE TO THINK
TONIGHT WILL BE COOLER WHEN COMPARED TO EARLY THIS MORNING...BUT
WITH LOW LEVEL RETURN FLOW EXPECTED TO INFILTRATE OUR AREA DURING
THE OVERNIGHT HOURS...OVERNIGHT LOWS TONIGHT SHOULD ACTUALLY BE
PRETTY CLOSE TO WHAT WE ARE EXPECTING EARLY THIS MORNING.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CST THU NOV 28 2013
THE FIRST PART OF THE LONG TERM FORECAST IS DRY WITH ABOVE NORMAL
TEMPERATURES...AFTERWHICH A MORE UNSETTLED...COLDER AND MORE
CHALLENGING FORECAST TAKES HOLD BY MID NEXT WEEK.
A TRANSITIONING WEST/NORTHWEST UPPER LEVEL FLOW WILL KEEP THE
REGION MAINLY DRY AND MILD THROUGH THROUGH THE REMAINDER OF THE
HOLIDAY WEEKEND. REGIONAL TRAVEL CONCERNS WILL BE NIL...AND BOTH
DAYTIME HIGHS AND NIGHTTIME LOWS WILL BE AT OR SLIGHTLY ABOVE
SEASONAL NORMALS. ONE NOTABLE WEATHER ELEMENT WILL THE WIND...OR
LACK THERE OF ON SATURDAY AND SUNDAY. THAT WILL HELP OFFSET ANY
COOLING FROM PASSING CLOUDS THROUGHOUT THE WEEKEND.
OVERALL...PRETTY NICE FOR THE END OF NOVEMBER. WARM ADVECTION
ASSOCIATED WITH WAVE ACROSS THE NORTHERN PLAINS SUNDAY WILL
THICKEN CLOUDS...BUT NOT TOO EXCITED ABOUT INCURRING ANY
MEASURABLE PRECIPITATION AT THIS POINT.
ACTUALLY THE MILD WEATHER WILL CONTINUE INTO THE FIRST PART OF
NEXT WEEK...ALTHOUGH THINGS WILL BE CHANGING AS UPPER LEVEL
HEIGHTS LOWER AND WE START TO SEE UPPER LEVEL LOW PRESSURE DEEPEN
IN THE GREAT BASIN REGION. AS THE LOW STRENGTHENS...AN INCREASING
SOUTH TO SOUTHEAST FLOW ACROSS THE CENTRAL/SOUTHERN PLAINS
DEVELOPS WHICH WILL KEEP TEMPERATURES ON THE MILD SIDE
MONDAY/TUESDAY. THERE IS SOME MODEL LIKENESS IN OVERALL
TRENDS...BUT VERY UNEASY IN TRYING TO PIN DOWN ANY SPECIFIC
DETAILS FOR NEXT WEEKS FORECAST AT THIS POINT. WE HAVE BEEN
ANTICIPATING A COLD AIR PUSH NEXT WEEK...AND THAT STILL LOOKS ON
TRACK FOR ABOUT WEDNESDAY...BUT THE COLD AIR PLUNGE COMES IN
PIECES WITH THE COLDEST AIR NOT LIKELY TO MAKE IT INTO THE AREA
UNTIL LATER NEXT WEEK. MODELS SUGGEST HEAVIEST PRECIPITATION
TRENDS WILL LIKELY BE ACROSS THE DAKOTAS AT THIS POINT...WITH ONLY
SMALL CHANCES FOR RAIN OR RAIN/SNOW MIX IN THE FORECAST AT THIS
POINT AS THE SYSTEM APPROACHES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 530 AM CST THU NOV 28 2013
MVFR CONDITIONS EXPECTED TO START THE TAF PERIOD...WITH VFR
CONDITIONS EXPECTED 15Z AND BEYOND.
AN AREA OF STRATUS HAS BEEN MOVING SOUTH FROM SOUTH DAKOTA ALL
NIGHT AND IS NOW MOVING INTO THE GRI AREA. THE CEILING WITHIN THIS
STRATUS GENERALLY RANGES BETWEEN 1000FT AND 1500FT AGL...THUS THE
MVFR FORECAST 12-15Z. GUIDANCE CONTINUES TO SUGGEST THIS STRATUS
WILL LIFT AND BREAK APART AFTER SUNRISE AS INCREASING DIABATIC
HEATING ALLOWS FOR INCREASING BOUNDARY LAYER DEPTH AND MIXING. VFR
CONDITIONS ARE CURRENTLY EXPECTED TO BE RESTORED BY 15Z...BUT THIS
WILL NEED TO BE MONITORED THROUGH THE NEXT FEW HOURS FOR POSSIBLE
UPDATES TO THE TAF. THE SURFACE WIND WILL REMAIN FROM THE
NORTH/NORTHEAST TODAY...SUSTAINED AT AROUND 10KTS. THE PASSAGE OF
A SURFACE RIDGE WILL THEN ALLOW FOR A WEAK...NO GREATER THAN
6KTS...SOUTHEASTERLY LOW LEVEL WIND FIELD OVERNIGHT TONIGHT.
VISIBILITY RESTRICTION IS NOT EXPECTED AT GRI THROUGH THE NEXT 24
HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...NOAA/NWS/BRYANT
LONG TERM...NOAA/NWS/MORITZ
AVIATION...NOAA/NWS/BRYANT
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
548 AM CST THU NOV 28 2013
.AVIATION...
12Z TAFS FOR KOMA...KOFK...KLNK
THE MAIN INITIAL ISSUE IS THE MVFR STRATUS DECK THAT HAS MOVED
INTO KOFK AND IS APPROACHING KOMA/KLNK. THE MODELS ARE NOT
HANDLING THIS DECK WELL WITH THE RUC13 LIKELY DOING THE BEST.
LATEST SAT IMAGERY INDICATES THE CLOUDS EWD PROGRESS HAS SLOWED
AND THIS IS INDICATED IN MOST MODELS THROUGH THE MORNING. THUS WE
WILL LEAVE THE DECK OUT OF KOMA FOR NOW...AND ALTHOUGH THE SWD
MOVEMENT HAS ALSO SLOWED WE WILL INCLUDE A TEMPO MVFR GROUP THIS
MORNING FOR A TIME AS THE CLOUDS ARE MORE LIKELY TO MAKE IT THERE
GIVEN THE 925 MB WINDS. OTHERWISE THE MVFR CLOUDS WILL SLOWLY
DISSIPATE THIS AFTERNOON AT KOFK...AND ONCE THIS OCCURS VFR
CONDITIONS ARE EXPECTED FOR THE REST OF THE PERIOD AT ALL SITES.
WINDS WILL START TO DIMINISH THIS AFTN AND WILL GO LIGHT
OVERNIGHT.
BOUSTEAD
&&
.PREV DISCUSSION... /ISSUED 329 AM CST THU NOV 28 2013/
DISCUSSION...
WATER VAPOR IMAGERY THIS MORNING SHOWING A DISTINCT CLOSED LOW
SPINNING JUST OFF THE WEST COAST ALONG WITH A WELL AMPLIFIED RIDGE
OVER THE WRN CONUS EXTENDING ALL THE WAY UP THE CANADIAN WEST COAST.
MEANWHILE BROAD DOWNSTREAM TROF WAS SITUATED OVER THE ERN CONUS.
HAVE OPTED TO MAKE SOME POP CHANGES IN THE EXTENDED PDS...IN
PARTICULAR MON THRU WED BASED ON 00Z ECM TRENDING TWD DRIER GFS
SOLUTION.
FIRST THOUGH...ANTICIPATED MODERATE WARMING TREND THRU EARLY NEXT
APPEARS TO BE ON TRACK. ALL THIS IN PART TO LARGE SCALE FLOW
TRANSITIONING TO SWLY WITH GRADUAL HGT RISES SPREADING OVER THE
CNTRL PLAINS. AND AT THIS POINT...MET/MEX/ECE MOS PROJECTING HIGHS
IN THE LOW/MID 40S LOOK PRETTY REASONABLE.
AS FOR PCPN CHANCES NEXT WEEK...WITH THE ECM/GFS IN SOMEWHAT BETTER
AGREEMENT...FEEL COMPELLED TO GO DRY ON MONDAY AS WELL AS TRIM POPS
BACK TO SLGT TUESDAY THRU THURSDAY. BOTH GENERALLY PLACE BRUNT OF
QPF FIELD NORTH OF THE CWA...WHICH THE CMC LENDS SOME CREDENCE TO.
BUFKIT/CRITICAL THNKS PROGS GENERALLY SUPPORT RA WITH POSSIBLE
RA/SN MIX DURING THE OVERNIGHT HOURS.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
530 AM CST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST THU NOV 28 2013
OVERNIGHT UPPER AIR ANALYSIS INDICATES MID TO UPPER LEVEL
TROUGHING OVER THE EASTERN CONUS...WITH A RIDGE OVER THE WEST AND
A MID LEVEL LOW OVER THE PACIFIC OFF THE CALIFORNIA COAST. A
SUBTLE MID LEVEL PERTURBATION IS ALSO NOTED OVER SOUTHERN
MINNESOTA...MOVING SOUTHEAST. MID TO UPPER LEVEL JET ENERGY
EXTENDS FROM SOUTH CENTRAL CANADA...SOUTHEAST INTO THE CENTRAL
CONUS...AND FINALLY EAST AND NORTHEAST ALONG THE EASTERN CONUS
INTO SOUTHEASTERN CANADA. MID TO UPPER LEVEL FLOW OVER OUR AREA
MAXES OUT AT AROUND 70KTS BETWEEN 300MB AND 200MB PER 00Z SOUNDING
DATA FROM KLBF AND KOAX. WATER VAPOR IMAGERY INDICATES INCREASED
VALUES OF MID LEVEL MOISTURE EXTENDING ALONG THE BACK SIDE OF THE
WEST COAST RIDGE...AS WELL AS FROM THE PACIFIC EASTWARD INTO
MEXICO AND THE SOUTHERN PLAINS. MID LEVEL MOISTURE OVER OUR AREA
HOWEVER REMAINS FAIRLY LIMITED. AT THE SURFACE...AN AREA OF LOW
BAROMETRIC PRESSURE EXISTS OVER NORTHWEST IOWA JUST AHEAD OF THE
AFOREMENTIONED MID LEVEL PERTURBATION...WITH AN ASSOCIATED COLD
FRONT EXTENDING FROM WESTERN IOWA INTO SOUTHEASTERN NEBRASKA AND
NORTHERN KANSAS. THIS FRONT HAS CLEARED MOST ALL OF OUR CWA AND AS
A RESULT...THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM
THE NORTH/NORTHWEST.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST NORTHWESTERLY MID TO UPPER LEVEL FLOW WILL PERSIST OVER
OUR AREA THROUGH THE NEXT 24 HOURS AS THE EASTERN CONUS TROUGH AND
WESTERN CONUS RIDGE BOTH TREK EAST. THE MID LEVEL
PERTURBATION...CURRENTLY OVER SOUTHERN MINNESOTA...IS EXPECTED TO
CONTINUE MOVING SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH NO
OTHER MID LEVEL SHORTWAVES/PERTURBATIONS EXPECTED TO IMPACT THE
REGION. AT THE SURFACE...THE AREA OF LOW BAROMETRIC
PRESSURE...CURRENTLY OVER NORTHWEST IOWA...SHOULD ALSO CONTINUE
MOVING TO THE EAST/SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH THE
ASSOCIATED LOW LEVEL BAROCLINIC ZONE PUSHING FARTHER
SOUTH/SOUTHEAST ACROSS THE PLAINS. THE LOW LEVEL WIND FIELD ACROSS
OUR AREA SHOULD REMAIN FROM THE NORTH/NORTHWEST THROUGH MUCH OF
TODAY AS A RESULT. THAT BEING SAID...GUIDANCE SUGGESTS THE PASSAGE
OF A SURFACE RIDGE TO EAST SHOULD ALLOW FOR LOW LEVEL RETURN FLOW
ACROSS OUR AREA DURING THE OVERNIGHT HOURS TONIGHT.
WITH AN OVERALL LACK IN OMEGA EXPECTED OVER OUR AREA...DRY
CONDITIONS ARE CURRENTLY FORECAST THROUGH THE NEXT 24 HOURS.
SATELLITE IMAGERY INDICATES A BAND OF STRATUS OVER MUCH OF THE
NORTHERN PLAINS THIS MORNING AND THIS STRATUS IS ADVANCING TO THE
SOUTH...ABOUT 150 MILES NORTH OF THE AFOREMENTIONED SURFACE FRONT.
GUIDANCE FROM THE NAM AND RAP BOTH SHOW THIS STRATUS...WITH HIGH
RELATIVE HUMIDITY VALUES AT 925MB NOTED ON PLAN VIEW
MAPS...INFILTRATING OUR NORTH/NORTHEASTERN CWA JUST PRIOR TO
SUNRISE THIS MORNING...BUT DISSIPATING POST-SUNRISE AS DIABATIC
HEATING RESULTS IN INCREASED BOUNDARY LAYER HEIGHT AND MIXING.
WENT AHEAD AND PLAYED PRETTY CLOSE TO NAM AND RAP GUIDANCE FOR THE
CLOUD FORECAST THROUGH THE FIRST PART OF THE SHORT TERM FORECAST
PERIOD...WITH THIS STRATUS EXPECTED TO IMPACT OUR NORTH/NORTHEAST
BY 10Z OR 11Z THIS MORNING...AND THEN DISSIPATE BY 15Z OR 16Z.
WITH LOW LEVEL RETURN FLOW INFILTRATING THE REGION TONIGHT...THERE
ARE INDICATIONS OF ISENTROPIC UPGLIDE AND SATURATION...PRIMARILY
ALONG THE 275-285K SURFACES...OVER THE HIGH PLAINS OF KANSAS AND
NEBRASKA. ALTHOUGH IT APPEARS MUCH OF OUR CWA SHOULD BE SPARED
FROM ANY STRATUS DEVELOPMENT THROUGH 12Z FRIDAY...925MB RELATIVE
HUMIDITY PLAN VIEW MAPS FROM THE NAM...OPERATIONAL GFS AND EC ALL
SUGGEST OUR EXTREME WEST/SOUTHWEST COULD ACTUALLY OBSERVE QUITE A
BIT OF CLOUD COVER TOWARDS SUNRISE FRIDAY AS THE EASTERN PERIPHERY
OF THE HIGH PLAINS STRATUS CLIPS THE AREA. WENT AHEAD WITH A
BROKEN CEILING ACROSS OUR EXTREME WEST/SOUTHWEST BY 12Z FRIDAY AS
A RESULT.
THE INTRUSION OF A COOLER LOW LEVEL AIRMASS BEHIND THE LOW LEVEL
BAROCLINIC ZONE SHOULD RESULT IN A COOLER DAY TODAY WHEN COMPARED
TO WEDNESDAY. HIGH TEMPERATURES GENERALLY IN THE MID 30S ACROSS
OUR NORTH...AND INTO THE MID 40S ACROSS OUR SOUTH...ARE FORECAST
FOR TODAY AS A RESULT. IT MIGHT OTHERWISE BE REASONABLE TO THINK
TONIGHT WILL BE COOLER WHEN COMPARED TO EARLY THIS MORNING...BUT
WITH LOW LEVEL RETURN FLOW EXPECTED TO INFILTRATE OUR AREA DURING
THE OVERNIGHT HOURS...OVERNIGHT LOWS TONIGHT SHOULD ACTUALLY BE
PRETTY CLOSE TO WHAT WE ARE EXPECTING EARLY THIS MORNING.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CST THU NOV 28 2013
THE FIRST PART OF THE LONG TERM FORECAST IS DRY WITH ABOVE NORMAL
TEMPERATURES...AFTERWHICH A MORE UNSETTLED...COLDER AND MORE
CHALLENGING FORECAST TAKES HOLD BY MID NEXT WEEK.
A TRANSITIONING WEST/NORTHWEST UPPER LEVEL FLOW WILL KEEP THE
REGION MAINLY DRY AND MILD THROUGH THROUGH THE REMAINDER OF THE
HOLIDAY WEEKEND. REGIONAL TRAVEL CONCERNS WILL BE NIL...AND BOTH
DAYTIME HIGHS AND NIGHTTIME LOWS WILL BE AT OR SLIGHTLY ABOVE
SEASONAL NORMALS. ONE NOTABLE WEATHER ELEMENT WILL THE WIND...OR
LACK THERE OF ON SATURDAY AND SUNDAY. THAT WILL HELP OFFSET ANY
COOLING FROM PASSING CLOUDS THROUGHOUT THE WEEKEND.
OVERALL...PRETTY NICE FOR THE END OF NOVEMBER. WARM ADVECTION
ASSOCIATED WITH WAVE ACROSS THE NORTHERN PLAINS SUNDAY WILL
THICKEN CLOUDS...BUT NOT TOO EXCITED ABOUT INCURRING ANY
MEASURABLE PRECIPITATION AT THIS POINT.
ACTUALLY THE MILD WEATHER WILL CONTINUE INTO THE FIRST PART OF
NEXT WEEK...ALTHOUGH THINGS WILL BE CHANGING AS UPPER LEVEL
HEIGHTS LOWER AND WE START TO SEE UPPER LEVEL LOW PRESSURE DEEPEN
IN THE GREAT BASIN REGION. AS THE LOW STRENGTHENS...AN INCREASING
SOUTH TO SOUTHEAST FLOW ACROSS THE CENTRAL/SOUTHERN PLAINS
DEVELOPS WHICH WILL KEEP TEMPERATURES ON THE MILD SIDE
MONDAY/TUESDAY. THERE IS SOME MODEL LIKENESS IN OVERALL
TRENDS...BUT VERY UNEASY IN TRYING TO PIN DOWN ANY SPECIFIC
DETAILS FOR NEXT WEEKS FORECAST AT THIS POINT. WE HAVE BEEN
ANTICIPATING A COLD AIR PUSH NEXT WEEK...AND THAT STILL LOOKS ON
TRACK FOR ABOUT WEDNESDAY...BUT THE COLD AIR PLUNGE COMES IN
PIECES WITH THE COLDEST AIR NOT LIKELY TO MAKE IT INTO THE AREA
UNTIL LATER NEXT WEEK. MODELS SUGGEST HEAVIEST PRECIPITATION
TRENDS WILL LIKELY BE ACROSS THE DAKOTAS AT THIS POINT...WITH ONLY
SMALL CHANCES FOR RAIN OR RAIN/SNOW MIX IN THE FORECAST AT THIS
POINT AS THE SYSTEM APPROACHES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 530 AM CST THU NOV 28 2013
MVFR CONDITIONS EXPECTED TO START THE TAF PERIOD...WITH VFR
CONDITIONS EXPECTED 15Z AND BEYOND.
AN AREA OF STRATUS HAS BEEN MOVING SOUTH FROM SOUTH DAKOTA ALL
NIGHT AND IS NOW MOVING INTO THE GRI AREA. THE CEILING WITHIN THIS
STRATUS GENERALLY RANGES BETWEEN 1000FT AND 1500FT AGL...THUS THE
MVFR FORECAST 12-15Z. GUIDANCE CONTINUES TO SUGGEST THIS STRATUS
WILL LIFT AND BREAK APART AFTER SUNRISE AS INCREASING DIABATIC
HEATING ALLOWS FOR INCREASING BOUNDARY LAYER DEPTH AND MIXING. VFR
CONDITIONS ARE CURRENTLY EXPECTED TO BE RESTORED BY 15Z...BUT THIS
WILL NEED TO BE MONITORED THROUGH THE NEXT FEW HOURS FOR POSSIBLE
UPDATES TO THE TAF. THE SURFACE WIND WILL REMAIN FROM THE
NORTH/NORTHEAST TODAY...SUSTAINED AT AROUND 10KTS. THE PASSAGE OF
A SURFACE RIDGE WILL THEN ALLOW FOR A WEAK...NO GREATER THAN
6KTS...SOUTHEASTERLY LOW LEVEL WIND FIELD OVERNIGHT TONIGHT.
VISIBILITY RESTRICTION IS NOT EXPECTED AT GRI THROUGH THE NEXT 24
HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...NOAA/NWS/BRYANT
LONG TERM...NOAA/NWS/MORITZ
AVIATION...NOAA/NWS/BRYANT
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
940 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 936 AM CST THU NOV 28 2013
MAIN CHALLENGE TODAY WILL BE CLOUD TRENDS AND TEMPERATURES. LATEST
SATELLITE IMAGERY SHOWING A GENERAL DECREASE IN CLOUD COVER ACROSS
THE REGION BEST DEPICTED BY RAP MESO-MODEL. WILL CONTINUE WITH A
GRADUAL DECREASE IN CLOUDS THROUGH THE MORNING BASED ON RAP
GUIDANCE AND CURRENT TRENDS. AT THIS POINT WITH EXPECTED PARTIAL SOLAR
WILL HOLD WITH TEMPERATURES FOR NOW. ONLY CHANGES WERE MINOR CLOUD
TREND ADJUSTMENTS.
UPDATE ISSUED AT 641 AM CST THU NOV 28 2013
CLOUDS CONTINUE TO BE A CHALLENGE. RAP/HRRR CIG GUIDANCE
INITIALIZES WITH CLEAR SKIES...BUT THEN DEVELOPS LOW CIGS DURING
THE AFTERNOON HOURS (LIKELY CU...LOW CONVECTIVE TEMPS) WHICH GET
TRAPPED UNDER THE RIDGE TONIGHT. RAP 925MB-850MB RH FIELD
ACTUALLY INDICATES THE DRYING THAT IS WORKING THROUGH THE
VALLEY...AND PROBABLY IS CLOSEST TO THE TRUTH. ADJUSTED THE SKY
GRIDS FOR CURRENT OBSERVATIONS AND LATEST RAP 925MB-850MB RH. NO
MAJOR CHANGES YET UNTIL MORE CONFIDENCE CAN BE OBTAINED WITH WHAT
EVER THE CLOUDS WILL DO TODAY.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
NORTHWEST FLOW ALOFT WILL CONTINUE INTO FRIDAY...WITH ANOTHER
SHORTWAVE EXPECTED FRIDAY INTO FRIDAY NIGHT. 00Z MODELS INDICATE
THAT THIS NEXT SHORTWAVE WILL TRACK FURTHER NORTH THAN THE ONE
YESTERDAY...KEEPING ACCUMULATING SNOWFALL OUTSIDE OF THE FA.
FOR TODAY...THE REGION WILL BE BETWEEN SHORTWAVES AS HIGH PRESSURE
BUILDS FROM THE NORTH. THIS WILL LEAVE CLOUD TRENDS AS THE MAIN
CHALLENGE. 09Z SATELLITE IMAGERY SHOWS CLEARING WORKING INTO THE
NORTHERN VALLEY. MODELS ARE STRUGGLING WITH THE CURRENT CLOUD
COVER...ALTHOUGH THE 07Z RAP IS CLOSEST WHEN LOOKING AT THE 925MB-
850MB RH FIELD. THIS MODEL INDICATES THAT CLEARING WILL CONTINUE
TO MOVE DOWN THE VALLEY...WITH CLOUDS DISSIPATING ALONG BOTH
EDGES THROUGH THE DAY. THIS SCENARIO MAKES SOME SENSE WITH THE
HIGH BUILDING INTO THE REGION. HOWEVER...CONVECTIVE TEMPS WILL BE
IN THE TEENS UNTIL LATE AFTERNOON...WHICH COULD LEAD TO
REDEVELOPMENT WITHIN CLEARING AREAS. DID DELAY THE CLEARING...BUT
REMAINED OPTIMISTIC THAT MOST AREAS WILL CLEAR THIS AFTERNOON.
ALSO...CONSIDERING CURRENT CONDITIONS...MENTIONED FLURRIES WITHIN
EXPECTED CLOUDY AREAS.
MIN TEMPS TONIGHT VERY DEPENDENT ON WHETHER OR NOT WE GET RID OF
THE CLOUDS TODAY. IF WE DO CLEAR...THERE WILL LIKELY WILL BE A
QUICK DROP THIS EVENING BEFORE RETURN FLOW KICKS IN AND TEMPS
BECOME STEADY AFTER MIDNIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
FRIDAY NIGHT-SATURDAY NIGHT...HIGH PRESSURE MOVING THROUGH SHOULD
LEAD TO DRY WEATHER. NOT SURE ABOUT CLOUD COVER (CONSIDERING
CURRENT CONDITIONS FOLLOWING A SHORTWAVE). CURRENT THOUGHT IS THAT
SINCE THE FRIDAY SHORTWAVE WILL TRACK FURTHER NORTH THAN THE
CURRENT SYSTEM...SHOULD BE LESS CLOUDS. ALSO...ANTICIPATE A WARMER
AIRMASS.
SUNDAY-WEDNESDAY...DETERMINISTIC MODEL RUNS CONTINUE TO SUGGEST A
MORE ACTIVE PATTERN TAKING SHAPE NEXT WEEK AS AN UPPER WAVE
CURRENTLY ACROSS ALASKA DIVES SOUTHWARD INTO THE WESTERN CONUS
DURING THE FIRST HALF OF NEXT WEEK...WITH ZONAL FLOW TRANSITIONING
TO SOUTHWEST FLOW ALOFT DOWNSTREAM ACROSS THE PLAINS. 00Z MODELS
SUGGEST THE POTENTIAL FOR SOME LIGHT SNOW WITH WARM ADVECTION LATER
SUNDAY INTO MONDAY. BEYOND THIS POINT...CONFIDENCE REGARDING ANY
PARTICULAR DETAILS IS VERY LOW...WITH SIGNIFICANT DIFFERENCES AMONG
MODELS IN HANDLING THE UPPER LONGWAVE TROUGH AND TIMING/PLACEMENT
OF EMBEDDED SHORTWAVE TROUGHS. THE LOW TO MID-LEVEL BAROCLINIC ZONE
WILL REMAIN POSITIONED ACROSS THE NORTHERN PLAINS THROUGH MID-WEEK
BEFORE ADVANCING SOUTHWARD. ANY WAVE EJECTING OUT OF THE BROADER
TROUGH TO THE WEST ALONG THIS BAROCLINIC ZONE WILL NEED TO BE
WATCHED FOR SFC CYCLONE DEVELOPMENT...WITH THE 00Z ECMWF INDICATING
A MORE SIGNIFICANT WAVE FOR THE MIDDLE OF THE WEEK. GIVEN THE VARIED
MODEL SOLUTIONS...CONTINUED WITH BROAD BRUSHED SLIGHT/CHANCE POPS
THROUGH MUCH OF THE PERIOD. TEMPS THROUGH MID-WEEK LOOK TO BE
SEASONABLE BEFORE COLDER AIR ARRIVES LATE IN THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 641 AM CST THU NOV 28 2013
LOW CONFIDENCE FORECAST FOR TODAY AS GUIDANCE IS PERFORMING POORLY
WITH THE CURRENT SITUATION. THE MOST LIKELY SCENARIO IS THAT MVFR
CIGS WILL REMAIN WEST OF THE VALLEY THROUGH MUCH OF THE
DAY...BREAKING UP BY THIS EVENING. SKY WITHIN THE VALLEY
(KGFK/KFAR) IS CURRENTLY CLEAR...AND SHOULD REMAIN THAT WAY (WITH
A BRIEF PERIOD OF MVFR CU DEVELOPMENT MID-DAY). ANTICIPATE
CLEARING EAST OF THE VALLEY BY EARLY TO MID AFTERNOON. WILL AMEND
THE TAFS IF MORE CONFIDENCE CAN BE OBTAINED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...TG
LONG TERM...TG/MAKOWSKI
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
646 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 646 AM CST THU NOV 28 2013
HIGH RESOLUTION MODELS INCLUDING RAP AND NAM NOT SHOWING MUCH
INDICATION OF LOW STRATUS SCATTERING OUT ANYTIME SOON. LATEST
SATELLITE IMAGERY DOES SHOW CLEARING WORKING SOUTH INTO
SOUTHWESTERN MANITOBA...AND THE LATEST RAP DOES DEPICT THIS AND
CONTINUES THE CLEARING SOUTH. THUS TRENDING SKY CONDITIONS SCT-BKN
OVER MY EAST AS THIS CLEARING DEVELOPS SOUTHWARD. MODELS ALSO
INDICATING THE WESTERN EDGE OF THE STRATUS DECK ERODING SO
TRENDED SKY OVER SOUTHWEST ND SCT-BKN AS WELL. OTHERWISE DO NOT
SEE CIGS SCOURING OUT TODAY ELSEWHERE. PIREP REPORTS FROM LAST
EVENING INDICATED THE THICKNESS OF THE STRATUS DECK AT AROUND
1500FT...SO MAY ONLY SEE THE EDGES ERODING TODAY WITH
REDEVELOPMENT TONIGHT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 419 AM CST THU NOV 28 2013
CURRENTLY...ARCTIC HIGH PRESSURE WAS CENTERED OVER NORTHERN
MANITOBA...WITH ITS AXIS EXTENDING SOUTHWESTWARD TO THE
MONTANA/NORTH DAKOTA BORDER. A WIDE AREA OF STRATUS CLOUDS WAS
SITUATED ON THE WESTERN AND SOUTHERN FRINGES OF THE ARCTIC HIGH. THE
STRATUS CLOUDS EXTENDED FROM NORTHERN ALBERTA/SASKATCHEWAN ACROSS
NORTHEASTERN MONTANA...ALL OF NORTH DAKOTA...MOST OF MINNESOTA AND
SOUTH DAKOTA...AND THE LEADING EDGE OF THE SOUTHERNMOST EXTENT WAS
NOSING INTO NORTHEASTERN NEBRASKA.
THE MAIN FORECAST CHALLENGES TODAY ARE SKY COVER AND TEMPERATURES.
THE STRATUS CLOUDS HAVE INHIBITED RADIATIONAL COOLING DURING THE
NIGHTTIME HOURS...AND THINK THE MORNING LOW TEMPERATURES OVER
WESTERN AND CENTRAL NORTH DAKOTA WILL BE HIGHER THAN FORECAST.
THE ARCTIC HIGH IS FORECAST TO MOVE EAST/SOUTHEAST TODAY...SUCH THAT
THE HIGH AXIS WOULD CROSS THE STATE WEST-TO-EAST AND THE AXIS WOULD
LIE ACROSS MINNESOTA/IOWA BY THIS EVENING...THEN CONTINUE MOVING
SOUTHEAST TOWARDS THE OHIO VALLEY TONIGHT.
THERE IS MUCH UNCERTAINTY IN HOW LONG THE STRATUS CLOUDS MAY LINGER
IN NORTH DAKOTA. THE MODELS ARE SUGGESTING THE STRATUS REMAINING
WELL-ENTRENCHED OVER THE STATE FOR THE MORNING HOURS...THEN BEGIN
ERODING FROM THE SOUTH THIS AFTERNOON AS WINDS SWITCH FROM NORTHWEST
TO SOUTHEAST AFTER THE HIGH AXIS MOVES THROUGH. HOWEVER...CONFIDENCE
IS LOW WHETHER CLOUDS WILL ERODE MUCH. THERE IS SUCH A WIDE SWATH OF
CLOUDS ASSOCIATED WITH THE WESTERN AND SOUTHERN PORTIONS OF THE
ARCTIC AIRMASS/HIGH...THAT AM THINKING ANY EROSION OF THE CLOUDS IN
SOUTHERN NORTH DAKOTA WOULD BE SHORT-LIVED...AND CLOUDS WOULD RETURN
DURING THE EVENING HOURS AS FORECAST LOW LEVEL MOISTURE FIELDS ARE
VERY HIGH IN THE MODELS. EVEN THIS IS SUSPECT...BECAUSE WARM
ADVECTION SHOULD BE TAKING PLACES FROM WEST TO EAST AS THE ARCTIC
HIGH EXITS THE REGION.
ALL OF THE UNCERTAINTY IN CLOUD COVER WILL IMPACT BOTH FORECAST MAX
TEMPERATURES TODAY AND MIN TEMPERATURES TONIGHT. THE LATEST MODEL
CONSENSUS WOULD RESULT IN MAX TEMPERATURES RANGING FROM THE TEENS
NORTH CENTRAL TO THE LOWER 30S SOUTHWEST...AND MINIMUM TEMPERATURES
TONIGHT RANGING FROM AROUND 5 ABOVE IN THE TURTLE MOUNTAINS TO
AROUND 20 IN THE FAR SOUTHWEST.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 419 AM CST THU NOV 28 2013
THE MAIN HIGHLIGHT IN THE LONG TERM FORECAST PERIOD CONTINUES TO
BE THE POTENTIAL FOR A PROLONGED PERIOD OF SEVERE WINTER WEATHER
FROM SUNDAY THROUGH THE MIDDLE OF NEXT WEEK. WILL STRESS AT THE
GET-GO THAT FORECAST UNCERTAINTY REMAINS HIGH AND CONFIDENCE BELOW
AVERAGE...ESPECIALLY MONDAY-WEDNESDAY.
THE EXTENDED PERIOD BEGINS FRIDAY MORNING WITH RELATIVELY WEAK
NORTHWEST FLOW ALOFT. AN EMBEDDED S/WV WILL BE MOVING EAST-
SOUTHEAST ACROSS NORTHERN SASKATCHEWAN/MANITOBA...WITH AN
ASSOCIATED SFC TROUGH AXIS APPROACHING THE FAR WESTERN DAKOTAS.
EXTENSIVE AREA OF LOW STRATUS CURRENTLY OVER THE REGION THIS
THURSDAY MORNING IS PROJECTED TO STILL HAVE SOME REMNANTS ALONG
TO AHEAD OF THIS BOUNDARY FRIDAY MORNING...SLOWLY ERODING WEST TO
EAST AND ACROSS THE SOUTHERN EXTENT AS THE FRONTAL BOUNDARY MOVES
ACROSS THE WEST AND CENTRAL PORTIONS OF THE STATE AS THE DAY
PROGRESSES. EXPECT A MAINLY DRY FROPA WITH MAINLY A MODERATE TO
HIGH PERCENT OF CLOUD COVER THE MAIN RESULT INTO FRIDAY NIGHT.
CAA FRIDAY NIGHT INTO SATURDAY WITH WEAK HIGH PRESSURE DEVELOPING
ACROSS THE REGION. DESPITE SOME CLOUD COVER...SATURDAY IS SHAPING
UP TO BE AN OVERALL PLEASANT LATE-FALL DAY WITH A WEAK SFC
PRESSURE GRADIENT RESULTING IN LIGHT WINDS AND TEMPERATURES
SEASONABLE AROUND 30 NORTH TO THE LOWER 40S SOUTHWEST. NOT A BAD
DAY TO WRAP UP OUTSIDE HOUSE WORK OR FINISH CHRISTMAS DECORATING
CONSIDERING WHAT IS IN STORE FOR US NEXT WEEK.
UPPER LEVEL LOW PRESSURE CURRENTLY SPINNING OVER ALASKA IS
FORECAST TO PROPAGATE SOUTHEAST ALONG THE BRITISH COLUMBIA COAST
SATURDAY NIGHT INTO SUNDAY NIGHT...POSITIONED OVER THE PACIFIC
NORTHWEST BY MONDAY MORNING. MODELS HAVE TRENDED A TAD MORE
CONSISTENT WITH LEAD S/WV APPROACHING AND MOVING THROUGH THE
NORTHERN PLAINS SUNDAY MORNING - SUNDAY NIGHT...ALONG WITH
INCREASING THERMAL UPGLIDE OVER THE WEST AND CENTRAL PORTIONS OF
THE STATE SUNDAY DAYTIME WITH A LEE SIDE SFC TROUGH TAKING SHAPE
JUST OFF TO OUR WEST OVER THE NORTHERN HIGH PLAINS OF MT/WY. 00Z
BUFFER DATA IS INDICATING THERE MAY BE ENOUGH ABOVE FREEZING MID
LEVEL AIR SUNDAY/SUNDAY NIGHT ACROSS THE SOUTHWEST FOR MIXED
PRECIPITATION WITH SUB-FREEZING SFC TEMPERATURES FORECAST.
ELSEWHERE THE PRECIP TYPE SHOULD BE ALL SNOW. GENERALLY LIGHT QPF
WITH THIS FIRST WAVE OF OVERRUNNING PRECIPITATION.
WILL NOT GET INTO DETAILS MONDAY-WEDNESDAY WITH STILL A WIDE
VARIETY OF SOLUTIONS ON THE EVENTUAL EVOLUTION OF THE PACIFIC
NORTHWEST LOW. THE 00Z GFS REMAINS MUCH MORE PROGRESSIVE AT
FIRST MONDAY AND TUESDAY WITH THE EASTWARD EXTENT OF THE LOW AND
THE LARGE SIZE OF CYCLONIC CIRCULATION...THEN MORPHING INTO A
SPLIT FLOW REGIME TUESDAY NIGHT - WED. THE LAST TWO RUNS (12Z ON
THE 27TH AND 00Z ON THE 28TH) OF THE ECMWF ARE MUCH LESS
PROGRESSIVE...MAINTAINING A CLOSED SYSTEM THROUGH WEDNESDAY NIGHT
OVER THE INTERMOUNTAIN WEST AND NORTHERN U.S. ROCKIES. THE 12Z RUN
MAINTAINED A CLOSED SYSTEM THROUGH THE WORKWEEK...WHILE THE LATEST
00Z RUN OF THE ECMWF NOW DEVELOPS SPLIT FLOW BY THURSDAY. EMBEDDED
ENERGY EJECTING OUT OF THIS FEATURE IMPOSSIBLE AT THIS TIME TO
ACCURATELY TIME OR TRACK SO LEANED ON ALLBLEND GUIDANCE WITH ZERO
EDITS FROM ITS OUTPUT DAYS 5-8. WILL MENTION THAT THE LAST TWO
ECMWF RUNS DO INDICATE HIGH QPF ACROSS SOUTH DAKOTA INTO SOUTHERN
NORTH DAKOTA BEGINNING TUESDAY NIGHT AND ENDING SOMETIME THURSDAY.
WITH THE COLD PROFILE ADVERTISED WOULD SEE SIGNIFICANT SNOW
ACCUMULATIONS BASED ON THESE TWO MODEL OUTPUTS ALONG TO SOUTH OF
I-94. WILL CONTINUE TO MONITOR.
&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 419 AM CST THU NOV 28 2013
LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW MVFR CIGS
ACROSS ALL OF NORTH DAKOTA EARLY THIS MORNING. EXPECT ALL
AERODROMES TO REMAIN MVFR THROUGH SUNRISE. CIGS SHOULD BEGIN TO
IMPROVE TO VFR DURING THE LATE AFTERNOON OR EARLY EVENING HOURS ON
THURSDAY. THERE IS MUCH UNCERTAINTY FOR WHEN/IF/TIMING OF MVFR
CLOUDS SCATTERING OUT DURING THE DAYLIGHT HOURS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 646 AM CST THU NOV 28 2013
LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW MVFR CIGS
ACROSS ALL OF NORTH DAKOTA EARLY THIS MORNING. EXPECT ALL
AERODROMES TO REMAIN MVFR THROUGH SUNRISE. CIGS SHOULD BEGIN TO
IMPROVE TO VFR DURING THE LATE AFTERNOON OR EARLY EVENING HOURS ON
THURSDAY. THERE IS MUCH UNCERTAINTY FOR WHEN/IF/TIMING OF MVFR
CLOUDS SCATTERING OUT DURING THE DAYLIGHT HOURS. AFTER 00Z LOWER
LEVEL CIGS EXPECTED TO REDEVELOP WITH MVFR CIGS AFTER 03Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...JV
LONG TERM...NH
AVIATION...JV
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
641 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 641 AM CST THU NOV 28 2013
CLOUDS CONTINUE TO BE A CHALLENGE. RAP/HRRR CIG GUIDANCE
INITIALIZES WITH CLEAR SKIES...BUT THEN DEVELOPS LOW CIGS DURING
THE AFTERNOON HOURS (LIKELY CU...LOW CONVECTIVE TEMPS) WHICH GET
TRAPPED UNDER THE RIDGE TONIGHT. RAP 925MB-850MB RH FIELD
ACTUALLY INDICATES THE DRYING THAT IS WORKING THROUGH THE
VALLEY...AND PROBABLY IS CLOSEST TO THE TRUTH. ADJUSTED THE SKY
GRIDS FOR CURRENT OBSERVATIONS AND LATEST RAP 925MB-850MB RH. NO
MAJOR CHANGES YET UNTIL MORE CONFIDENCE CAN BE OBTAINED WITH WHAT
EVER THE CLOUDS WILL DO TODAY.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
NORTHWEST FLOW ALOFT WILL CONTINUE INTO FRIDAY...WITH ANOTHER
SHORTWAVE EXPECTED FRIDAY INTO FRIDAY NIGHT. 00Z MODELS INDICATE
THAT THIS NEXT SHORTWAVE WILL TRACK FURTHER NORTH THAN THE ONE
YESTERDAY...KEEPING ACCUMULATING SNOWFALL OUTSIDE OF THE FA.
FOR TODAY...THE REGION WILL BE BETWEEN SHORTWAVES AS HIGH PRESSURE
BUILDS FROM THE NORTH. THIS WILL LEAVE CLOUD TRENDS AS THE MAIN
CHALLENGE. 09Z SATELLITE IMAGERY SHOWS CLEARING WORKING INTO THE
NORTHERN VALLEY. MODELS ARE STRUGGLING WITH THE CURRENT CLOUD
COVER...ALTHOUGH THE 07Z RAP IS CLOSEST WHEN LOOKING AT THE 925MB-
850MB RH FIELD. THIS MODEL INDICATES THAT CLEARING WILL CONTINUE
TO MOVE DOWN THE VALLEY...WITH CLOUDS DISSIPATING ALONG BOTH
EDGES THROUGH THE DAY. THIS SCENARIO MAKES SOME SENSE WITH THE
HIGH BUILDING INTO THE REGION. HOWEVER...CONVECTIVE TEMPS WILL BE
IN THE TEENS UNTIL LATE AFTERNOON...WHICH COULD LEAD TO
REDEVELOPMENT WITHIN CLEARING AREAS. DID DELAY THE CLEARING...BUT
REMAINED OPTIMISTIC THAT MOST AREAS WILL CLEAR THIS AFTERNOON.
ALSO...CONSIDERING CURRENT CONDITIONS...MENTIONED FLURRIES WITHIN
EXPECTED CLOUDY AREAS.
MIN TEMPS TONIGHT VERY DEPENDENT ON WHETHER OR NOT WE GET RID OF
THE CLOUDS TODAY. IF WE DO CLEAR...THERE WILL LIKELY WILL BE A
QUICK DROP THIS EVENING BEFORE RETURN FLOW KICKS IN AND TEMPS
BECOME STEADY AFTER MIDNIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
FRIDAY NIGHT-SATURDAY NIGHT...HIGH PRESSURE MOVING THROUGH SHOULD
LEAD TO DRY WEATHER. NOT SURE ABOUT CLOUD COVER (CONSIDERING
CURRENT CONDITIONS FOLLOWING A SHORTWAVE). CURRENT THOUGHT IS THAT
SINCE THE FRIDAY SHORTWAVE WILL TRACK FURTHER NORTH THAN THE
CURRENT SYSTEM...SHOULD BE LESS CLOUDS. ALSO...ANTICIPATE A WARMER
AIRMASS.
SUNDAY-WEDNESDAY...DETERMINISTIC MODEL RUNS CONTINUE TO SUGGEST A
MORE ACTIVE PATTERN TAKING SHAPE NEXT WEEK AS AN UPPER WAVE
CURRENTLY ACROSS ALASKA DIVES SOUTHWARD INTO THE WESTERN CONUS
DURING THE FIRST HALF OF NEXT WEEK...WITH ZONAL FLOW TRANSITIONING
TO SOUTHWEST FLOW ALOFT DOWNSTREAM ACROSS THE PLAINS. 00Z MODELS
SUGGEST THE POTENTIAL FOR SOME LIGHT SNOW WITH WARM ADVECTION LATER
SUNDAY INTO MONDAY. BEYOND THIS POINT...CONFIDENCE REGARDING ANY
PARTICULAR DETAILS IS VERY LOW...WITH SIGNIFICANT DIFFERENCES AMONG
MODELS IN HANDLING THE UPPER LONGWAVE TROUGH AND TIMING/PLACEMENT
OF EMBEDDED SHORTWAVE TROUGHS. THE LOW TO MID-LEVEL BAROCLINIC ZONE
WILL REMAIN POSITIONED ACROSS THE NORTHERN PLAINS THROUGH MID-WEEK
BEFORE ADVANCING SOUTHWARD. ANY WAVE EJECTING OUT OF THE BROADER
TROUGH TO THE WEST ALONG THIS BAROCLINIC ZONE WILL NEED TO BE
WATCHED FOR SFC CYCLONE DEVELOPMENT...WITH THE 00Z ECMWF INDICATING
A MORE SIGNIFICANT WAVE FOR THE MIDDLE OF THE WEEK. GIVEN THE VARIED
MODEL SOLUTIONS...CONTINUED WITH BROADBRUSHED SLIGHT/CHANCE POPS
THROUGH MUCH OF THE PERIOD. TEMPS THROUGH MID-WEEK LOOK TO BE
SEASONABLE BEFORE COLDER AIR ARRIVES LATE IN THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 641 AM CST THU NOV 28 2013
LOW CONFIDENCE FORECAST FOR TODAY AS GUIDANCE IS PERFORMING POORLY
WITH THE CURRENT SITUATION. THE MOST LIKELY SCENARIO IS THAT MVFR
CIGS WILL REMAIN WEST OF THE VALLEY THROUGH MUCH OF THE
DAY...BREAKING UP BY THIS EVENING. SKY WITHIN THE VALLEY
(KGFK/KFAR) IS CURRENTLY CLEAR...AND SHOULD REMAIN THAT WAY (WITH
A BRIEF PERIOD OF MVFR CU DEVELOPMENT MID-DAY). ANTICIPATE
CLEARING EAST OF THE VALLEY BY EARLY TO MID AFTERNOON. WILL AMEND
THE TAFS IF MORE CONFIDENCE CAN BE OBTAINED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...TG
LONG TERM...TG/MAKOWSKI
AVIATION...TG
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
949 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 949 AM CST THU NOV 28 2013
CLOUDS ARE PROVIDING THE GREATEST CHALLENGE FOR THE SHORT TERM
TODAY. FAIRLY EXTENSIVE CLOUDS PRESENT EARLY THIS MORNING HAVE
DIMINISHED IN COVERAGE EAST...BUT ARE FAIRLY SOLID FOR THE TIME
WEST. BASED ON KABR/KBIS MORNING RAOBS...THESE CLOUDS ARE FAIRLY
SHALLOW...BUT IMPRESSIVELY TRAPPED BELOW INVERSION...MAKING THE
DISSIPATION LIKELY TO BE A RESULT OF DRYING AND LIMITED HEATING
BELOW INVERSION AS WELL AS AN ADVECTIVE COMPONENT. RAP ON THE RIGHT
TRACK...BUT TOO PESSIMISTIC TOWARD I 29 CORRIDOR. AT THIS TIME...
CLOUDS LOOK TO BE FAIRLY TOUGH TO SHAKE IN THE WEST/SOUTHWEST CWA
WHILE THOSE AREAS IN ADVANCE OF THE LOW LEVEL RIDGE AXIS FROM
AROUND I29 EASTWARD ARE CERTAIN TO FIND A MIX OF CLOUDS AND SUN
THROUGH MIDDAY AND THEN TRENDING TOWARD MORE SUN. BASED ON TEMPS
ON CLOUD BEARING LEVEL AS WELL AS UPSTREAM OBSERVATIONS...HAVE
ADDED IN A FEW FLURRIES TO AREAS AS FAR SOUTH AS AROUND KFSD...BUT
EXPECT STRONGER COVERAGE OF LOW REFLECTIVITIES ON KABR RADAR TO
DWINDLE SOMEWHAT WITH INCREASING DISTANCE FROM WEAK TERRAIN
SUPPORT. EARLIER FLURRIES IN SW MN COULD HAVE IMPACTED SOMEWHAT
MORE RAPID DISSIPATION IN CLOUDS...AND MAY ALSO INFLUENCE THE
CLEARING TREND. TEMPS ALSO CHALLENGING WITH CONTINUED LOW LEVEL
COLD AIR ADVECTION...BUT TEMPS ALREADY REACHING INDICATED MIXING
POTENTIAL UNDER CLOUDY AREAS BY MID MORNING. PROBABLY NOT MUCH
ROOM TO WARM MORE THAN A FEW DEGREES ANYWHERE TODAY...MOST SO IN
AREAS WITH SUNSHINE TO THE EAST. UPDATES OUT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM CST THU NOV 28 2013
CURRENT SURFACE ANALYSIS SHOWS THE FRONTAL BOUNDARY HAVING PUSHED
THROUGH OUR CWA EARLY THIS MORNING...WITH AN AREA OF STRATUS
STREAMING INTO OUR WESTERN CWA BEHIND THE EXITING SYSTEM. THE
SURFACE RIDGE AXIS PRESENTLY LOCATED THROUGH THE WESTERN PORTIONS OF
THE DAKOTA WILL SLIDE TO THE SOUTH AND EAST TODAY...AND WITH DRYING
AND SUBSIDENCE LOOKING FOR THE LOW CLOUDS TO THIN OUT ACROSS THE
AREA BY LATE MORNING OR EARLY AFTERNOON. OTHERWISE...IT WILL BE
BREEZY DURING THE EARLY PART OF THE DAY...ESPECIALLY IN THE
EAST...WITH COLD AIR ADVECTION AND A DECENT GRADIENT ACROSS THE
AREA...THEN TAPERING DOWN IN THE AFTERNOON AS HIGH PRESSURE BUILDS
IN AND THE GRADIENT RELAXES AND ML WINDS DECREASE. THERMAL PROFILES
DO COOL A BIT TODAY...THOUGH NOTHING TOO EXTREME WITH HIGHS STILL
MAKING IT INTO THE MID 20S TO LOWER 30S FROM NORTHEAST TO SOUTHWEST
RESPECTIVELY.
THE HIGH PRESSURE MOVES QUICKLY TO THE EAST TONIGHT...AND WITH THAT
WINDS WILL TRANSITION TO SOUTHEASTERLY AND PICK UP LATER AT NIGHT.
IT WILL STILL BE A COLD NIGHT WITH LOWS IN THE UPPER SINGLE DIGITS
TO TEENS...WITH TEMPS STEADYING OUT OR RISING SOME LATE AT NIGHT AS
THE WINDS INCREASE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 520 AM CST THU NOV 28 2013
POTENT PACIFIC LOW DIVES INTO THE PACIFIC NORTHWEST FRIDAY AND
SATURDAY...SHIFTING THE INTERMOUNTAIN WEST RIDGING ITO THE PLAINS
STATES. A STRONG PUSH OF WARM AIR ADVECTION AND BREEZY SOUTHERLY
WINDS WILL BRING MILDER TEMPERATURES ON FRIDAY DESPITE SOME PASSING
MID AND HIGH CLOUDS FILTERING THE SUNSHINE. HIGHS WILL WARM TO
SLIGHTLY ABOVE NORMAL READINGS IN THE LOW 30S EAST TO THE MID 40S
WEST. A WEAK FRONT SAGS ACROSS THE FORECAST AREA FRIDAY NIGHT
THROUGH SATURDAY MORNING...BUT WITHOUT MOISTURE OR A REAL COLD AIR
PUSH BEHIND IT...CONDITIONS WILL REMAIN DRY AND MILD WITH HIGHS
MIXING INTO THE UPPER 30S TO MID 40S.
MUCH GREATER UNCERTAINTY SHOWS UP EARLY NEXT WEEK AS THE PACIFIC
TROUGH STRENGTHENS AND MOVES INTO THE NORTHERN ROCKIES. MODELS STILL
SHOWING SIGNIFICANT DIFFERENCES IN THE STRENGTH...TIMING AND TRACK
OF THE UPPER LOW. THE GFS FOLLOWS A MORE NORTHERLY TRACK WHILE THE
ECMWF IS SLOWER AND FURTHER SOUTH. FINALLY...THE CANADIAN DEPICTS A
MUCH WEAKER SYSTEM OVERALL WHICH GIVEN THE ENERGETIC NATURE OF THIS
SYSTEM SEEMS THE LEAST LIKELY.
INITIAL SHORTWAVE AHEAD OF THE MAIN SYSTEM SLIDES SOUTHEAST ACROSS
THE REGION AROUND THE SUNDAY NIGHT/MONDAY TIME FRAME. WITH THE GFS
RAPIDLY AMPLIFYING THE PAC NW TROUGH AND UPPER RIDGE AHEAD OF
IT...THIS WAVE IS WEAKER AND FASTER MOVING THAN THE ECMWF WHICH
DEVELOPS AN INVERTED TROUGH FEATURE OVER THE NORTHERN AND CENTRAL
PLAINS AND KEEPS IT IN THE PICTURE WELL INTO TUESDAY. SIGNIFICANT
DIFFERENCES IN TEMPERATURE PROFILES ALSO MAKE PRECIPITATION TYPES
DIFFICULT TO PINPOINT. TEMPERATURES LOOK TO REMAIN SEASONALLY MILD
THROUGH WEDNESDAY WITH MUCH COOLER READINGS ARRIVING LATE IN THE
WEEK. FOR NOW WILL KEEP MENTION OF BOTH RAIN AND SNOW. NOT MUCH
CONFIDENCE IN THE TIMING OF THE PRECIPITATION BUT CHANCES DO APPEAR
TO IMPROVE AS WE MOVE TOWARDS MID WEEK AS THE MAIN PACIFIC TROUGH
ADVANCES TOWARDS THE REGION. FOR NOW DID NOT ALTER THE ALLBLEND POPS
OR TEMPS MUCH GIVEN SUCH UNCERTAINTY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 520 AM CST THU NOV 28 2013
STRATUS CONTINUES TO EXPAND SOUTHWARD BEHIND EXITING COLD
FRONT...AND THE CHALLENGE BECOMES WHEN THIS AREA OF LOW CLOUDS
WILL BREAK UP. WITH HIGH PRESSURE BUILDING ACROSS THE REGION AND
ASSOCIATED SUBSIDENCE AND DRYING...WOULD EXPECT CLOUDS TO BEGIN TO
DISSIPATE BY MID AFTERNOON. THERE IS SOME DISAGREEMENT AMONG
MODELS...WITH THE RAP HOLDING IT IN THROUGH AT LEAST LATE
AFTERNOON. AT THIS POINT WILL LEAN A LITTLE EARLIER WITH CLOUDS
SCATTERING OUT MOST PLACES AFTER AROUND 19Z. OTHERWISE...NORTHWESTERLY
WINDS...GUSTY AT TIMES EARLY...WILL TAPER DOWN...BECOMING LIGHT BY
THIS EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHAPMAN
SHORT TERM...
LONG TERM...JM
AVIATION...JM
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
528 AM CST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM CST THU NOV 28 2013
CURRENT SURFACE ANALYSIS SHOWS THE FRONTAL BOUNDARY HAVING PUSHED
THROUGH OUR CWA EARLY THIS MORNING...WITH AN AREA OF STRATUS
STREAMING INTO OUR WESTERN CWA BEHIND THE EXITING SYSTEM. THE
SURFACE RIDGE AXIS PRESENTLY LOCATED THROUGH THE WESTERN PORTIONS OF
THE DAKOTA WILL SLIDE TO THE SOUTH AND EAST TODAY...AND WITH DRYING
AND SUBSIDENCE LOOKING FOR THE LOW CLOUDS TO THIN OUT ACROSS THE
AREA BY LATE MORNING OR EARLY AFTERNOON. OTHERWISE...IT WILL BE
BREEZY DURING THE EARLY PART OF THE DAY...ESPECIALLY IN THE
EAST...WITH COLD AIR ADVECTION AND A DECENT GRADIENT ACROSS THE
AREA...THEN TAPERING DOWN IN THE AFTERNOON AS HIGH PRESSURE BUILDS
IN AND THE GRADIENT RELAXES AND ML WINDS DECREASE. THERMAL PROFILES
DO COOL A BIT TODAY...THOUGH NOTHING TOO EXTREME WITH HIGHS STILL
MAKING IT INTO THE MID 20S TO LOWER 30S FROM NORTHEAST TO SOUTHWEST
RESPECTIVELY.
THE HIGH PRESSURE MOVES QUICKLY TO THE EAST TONIGHT...AND WITH THAT
WINDS WILL TRANSITION TO SOUTHEASTERLY AND PICK UP LATER AT NIGHT.
IT WILL STILL BE A COLD NIGHT WITH LOWS IN THE UPPER SINGLE DIGITS
TO TEENS...WITH TEMPS STEADYING OUT OR RISING SOME LATE AT NIGHT AS
THE WINDS INCREASE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 520 AM CST THU NOV 28 2013
POTENT PACIFIC LOW DIVES INTO THE PACIFIC NORTHWEST FRIDAY AND
SATURDAY...SHIFTING THE INTERMOUNTAIN WEST RIDGING ITO THE PLAINS
STATES. A STRONG PUSH OF WARM AIR ADVECTION AND BREEZY SOUTHERLY
WINDS WILL BRING MILDER TEMPERATURES ON FRIDAY DESPITE SOME PASSING
MID AND HIGH CLOUDS FILTERING THE SUNSHINE. HIGHS WILL WARM TO
SLIGHTLY ABOVE NORMAL READINGS IN THE LOW 30S EAST TO THE MID 40S
WEST. A WEAK FRONT SAGS ACROSS THE FORECAST AREA FRIDAY NIGHT
THROUGH SATURDAY MORNING...BUT WITHOUT MOISTURE OR A REAL COLD AIR
PUSH BEHIND IT...CONDITIONS WILL REMAIN DRY AND MILD WITH HIGHS
MIXING INTO THE UPPER 30S TO MID 40S.
MUCH GREATER UNCERTAINTY SHOWS UP EARLY NEXT WEEK AS THE PACIFIC
TROUGH STRENGTHENS AND MOVES INTO THE NORTHERN ROCKIES. MODELS STILL
SHOWING SIGNIFICANT DIFFERENCES IN THE STRENGTH...TIMING AND TRACK
OF THE UPPER LOW. THE GFS FOLLOWS A MORE NORTHERLY TRACK WHILE THE
ECMWF IS SLOWER AND FURTHER SOUTH. FINALLY...THE CANADIAN DEPICTS A
MUCH WEAKER SYSTEM OVERALL WHICH GIVEN THE ENERGETIC NATURE OF THIS
SYSTEM SEEMS THE LEAST LIKELY.
INITIAL SHORTWAVE AHEAD OF THE MAIN SYSTEM SLIDES SOUTHEAST ACROSS
THE REGION AROUND THE SUNDAY NIGHT/MONDAY TIME FRAME. WITH THE GFS
RAPIDLY AMPLIFYING THE PAC NW TROUGH AND UPPER RIDGE AHEAD OF
IT...THIS WAVE IS WEAKER AND FASTER MOVING THAN THE ECMWF WHICH
DEVELOPS AN INVERTED TROUGH FEATURE OVER THE NORTHERN AND CENTRAL
PLAINS AND KEEPS IT IN THE PICTURE WELL INTO TUESDAY. SIGNIFICANT
DIFFERENCES IN TEMPERATURE PROFILES ALSO MAKE PRECIPITATION TYPES
DIFFICULT TO PINPOINT. TEMPERATURES LOOK TO REMAIN SEASONALLY MILD
THROUGH WEDNESDAY WITH MUCH COOLER READINGS ARRIVING LATE IN THE
WEEK. FOR NOW WILL KEEP MENTION OF BOTH RAIN AND SNOW. NOT MUCH
CONFIDENCE IN THE TIMING OF THE PRECIPITATION BUT CHANCES DO APPEAR
TO IMPROVE AS WE MOVE TOWARDS MID WEEK AS THE MAIN PACIFIC TROUGH
ADVANCES TOWARDS THE REGION. FOR NOW DID NOT ALTER THE ALLBLEND POPS
OR TEMPS MUCH GIVEN SUCH UNCERTAINTY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 520 AM CST THU NOV 28 2013
STRATUS CONTINUES TO EXPAND SOUTHWARD BEHIND EXITING COLD
FRONT...AND THE CHALLENGE BECOMES WHEN THIS AREA OF LOW CLOUDS
WILL BREAK UP. WITH HIGH PRESSURE BUILDING ACROSS THE REGION AND
ASSOCIATED SUBSIDENCE AND DRYING...WOULD EXPECT CLOUDS TO BEGIN TO
DISSIPATE BY MID AFTERNOON. THERE IS SOME DISAGREEMENT AMONG
MODELS...WITH THE RAP HOLDING IT IN THROUGH AT LEAST LATE
AFTERNOON. AT THIS POINT WILL LEAN A LITTLE EARLIER WITH CLOUDS
SCATTERING OUT MOST PLACES AFTER AROUND 19Z. OTHERWISE...NORTHWESTERLY
WINDS...GUSTY AT TIMES EARLY...WILL TAPER DOWN...BECOMING LIGHT BY
THIS EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...JM
AVIATION...JM
SEE BELOW FOR AN UPDATED AVIATION FORECAST DISCUSSION.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
AN EXTENSIVE STRATUS DECK OVER THE REGION IS KEEPING TEMPERATURES
RELATIVELY MILD WITH CURRENT READINGS IN THE MID 20S. BASED ON THE
PAST FEW RUNS OF THE RUC...IT SEEMS UNLIKELY THIS STRATUS DECK
WILL DISSIPATE ANYTIME SOON. WOULD NOT BE TOO SURPRISED IF THESE
CLOUDS HANG AROUND THROUGH THIS AFTERNOON BEFORE DRIER AIR AT 925
MB MOVES IN FROM THE SOUTHWEST. OF COURSE THESE CLOUDS WILL MAKE
FORECASTING HIGH TEMPERATURES RATHER DIFFICULT. HAVE RELIED UPON
THE RUC MODEL WHICH SHOWS A SLIGHT COOL DOWN AROUND SUNRISE...THEN
A SLIGHT INCREASE BY 21Z.
HIGH PRESSURE SHIFTS EAST OF THE REGION TONIGHT...ALLOWING WAA TO
SPREAD ACROSS THE WESTERN CWA WHERE TEMPERATURES SHOULD BECOME
STEADY OR SLOWLY RISE AFTER MIDNIGHT. ANOTHER WEAK LOW PRESSURE
SYSTEM PASSING ACROSS THE REGION ON FRIDAY WILL BRING WARM
TEMPERATURES BACK INTO THE AREA. TEMPS AT 925/850 MB ARE PROJECTED
TO RANGE AROUND NORMAL...WHICH WHEN COMBINED WITH DECENT MIXING
WINDS SHOULD EQUAL HIGHS IN THE MID 30S...TO THE MID 40S. WOULD
NOT BE TOO SURPRISED IF HIGH TEMPERATURES END UP BEING WARMER.
SLIGHTLY COOLER LOW LEVEL TEMPERATURES ALONG WITH WEAK CAA ON
SATURDAY WILL RESULT IN HIGHS IN THE LOW TO MID 30S.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
LATEST MODEL RUNS CONTINUE TO FORECAST A MAJOR PATTERN SHIFT
DURING THE LONG TERM. HOWEVER THE DETAILS REMAIN SKETCHY AS EACH
MODEL HAS ITS OWN IDEA ON HOW TO HANDLE ENERGY WITHIN THE
DEVELOPING MID LEVEL TROF AND THAT TROFS EVOLUTION THROUGH THE
MIDDLE OF NEXT WEEK. THE ECMWF IS BY FAR THE MOST AGGRESSIVE IN
SETTING UP A BAROCLINIC ZONE ACROSS THE REGION AND CRANKS OUT
COPIOUS AMOUNTS OF PCPN FROM TUESDAY THROUGH THURSDAY. THE GFS IS
MORE PROGRESSIVE AND FEATURES A MORE POSITIVE TILT MID LEVEL TROF
OVER THE WESTERN/CENTRAL CONUS LEADING TO A LESS INTENSE
BAROCLINIC ZONE OVER THE NORTHERN PLAINS. THE LAST COUPLE RUNS OF
THE ECMWF HAVE BEEN CONSISTENTLY SLOWER AND WETTER VS THE GFS.
BUT IT SEEMS OVERLY WET. NONETHELESS WILL BE AN INTERESTING MIDDLE
OF NEXT WEEK WEATHER-WISE WITH A MIXED BAG OF PCPN EXPECTED NO
MATTER WHICH MODEL YOU LIKE. TEMPERATURES ARE EXPECTED TO BE ABOVE
NORMAL FOR THE FIRST PART OF THE PERIOD...BUT THEN TRANSITION
TOWARD NORMAL AS COLDER AIR INVADES FROM CANADA TOWARD MID TO LATE
WEEK.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
MVFR CIGS ARE EXPECTED TO PERSIST AT LEAST INTO THE AFTERNOON FOR MOST
TERMINALS. MOST AREAS SHOULD BECOME VFR BY EVENING.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...TDK
SHORT TERM...SD
LONG TERM...TDK
AVIATION...TDK
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
333 AM MST THU NOV 28 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 332 AM MST THU NOV 28 2013
10Z SURFACE ANALYSIS SHOWS THE COLD FRONT BISECTING THE CWA FROM
NORTHWEST TO SOUTHEAST WITH LIGHT WINDS THROUGHOUT THE AREA. HIGH
CLOUDS ARE STREAMING OVERHEAD IN NORTHWEST FLOW WITH A STRATUS DECK
CREEPING SOUTH-SOUTHWESTWARD ACROSS THE CENTRAL PLAINS AND TOWARD
THE NORTHERN NEBRASKA PANHANDLE. CURRENT TRENDS COMBINED WITH NAM
BUFKIT SOUNDINGS AND RECENT HRRR RUNS SUGGEST THAT THIS STRATUS DECK
WILL IMPACT CHADRON AROUND SUNRISE AND MAY SNEAK INTO ALLIANCE AS
WELL THROUGH THE MORNING. GUIDANCE ALSO SUGGESTS THE LOW CLOUDS WILL
PERSIST THROUGH THE MORNING...AND WILL SCATTER OUT SLOWLY WITH
INCREASED SOLAR INSOLATION. IN ADDITION...SOUTHEASTERLY WINDS WILL
BECOME BREEZY ACROSS THE EASTERN PLAINS AS THE SFC HIGH SLIDES
SOUTH-SOUTHEAST ACROSS THE CENTRAL PLAINS. THIS WILL ADVECT SOME
LLVL MOISTURE INTO THE EASTERN PLAINS AND LIKELY CONTRIBUTE TO THE
SLOWER MIXING OUT OF THE STRATUS. INCREASED CLOUD COVER FOR TODAY IN
THIS AREA AS A RESULT...AND LOWERED MAX TEMPS A FEW DEGREES DUE TO THE
MORE PERSISTENT CLOUD DECK. OTHERWISE...EXPECTING A DRY...CALM
THANKSGIVING DAY WITH LIGHT WINDS AND CONTINUAL HIGH CIRRUS MOVING
OVERHEAD FROM THE NORTHWEST.
TONIGHT...A SHORTWAVE WILL MOVE EASTWARD ACROSS CENTRAL CANADA WHILE
A SECOND WEAK WAVE WILL MOVE ACROSS COLORADO. THE COMBINATION OF
FEATURES WILL DEEPEN THE LEESIDE SFC PRESSURE TROUGH...ALTHOUGH THE
DEEPEST PRESSURE FALLS WILL REMAIN WELL REMOVED FROM THE REGION AND
THEREFORE THE SFC PRESSURE GRADIENT WILL NOT BECOME VERY STRONG.
STILL LOOKING AT 850/700 MB CAG-CPR GRADIENTS OF 30 DAM OR LESS BY
EARLY FRIDAY MORNING. A LOOK AT A CROSS SECTION OF LAPSE RATES AND
WINDS THROUGH THE WIND PRONE REGIONS ALONG AND WEST OF THE LARAMIE
RANGE SHOWS THE INCREASE IN WINDS WITH THE STRENGTHENING
GRADIENT...BUT THE INVERSION REMAINS NEAR THE GROUND EARLY FRIDAY
MORNING WHICH SHOULD MINIMIZE GAP EFFECTS. THE INVERSION WILL LIFT
JUST OFF THE SURFACE AND WILL REMAIN RELATIVELY WEAK THROUGH
FRIDAY...BUT SHOULD BE STRONG ENOUGH TO PRODUCE MODERATE
GRADIENT/GAP WINDS THROUGH FRIDAY NIGHT. LOOKING AT SUSTAINED
WEST-SOUTHWEST WINDS IN THIS AREA ON AVERAGE OF 25 TO 35 MPH WITH A
FEW PERIODS OF STRONGER WINDS IN THE MORNING HOURS AS THE INVERSION
BEGINS TO LIFT. GUSTS SHOULD REMAIN WITHIN THE 50 TO 55 MPH ZONE AS
WINDS JUST OFF THE SURFACE ARE PROGGED TO ONLY BE AS HIGH AS 40 KTS.
LASTLY FOR FRIDAY...LITTLE CHANGE TO THE AIRMASS OUT IN THE FAR
WESTERN PORTIONS OF THE FORECAST AREA ON FRIDAY MORNING SUGGESTS A
RETURN OF STRATUS AND PATCHY FOG IN FAR SOUTHWESTERN CARBON COUNTY.
WITH LITTLE CHANGE IN THE SYNOPTIC PATTERN ON SATURDAY...EXPECT
MODERATE WINDS TO CONTINUE THROUGH AT LEAST SATURDAY AFTERNOON. BREEZY
WEST-NORTHWEST WINDS WILL EXPAND WESTWARD AND JUST TO THE LEE OF THE
MOUNTAINS DURING THE AFTERNOON HOURS AS THE INVERSION LIFTS...WHICH
WILL WARM TEMPS ACROSS THE EASTERN PLAINS BACK INTO THE 50S FOR
FRIDAY AND SATURDAY DUE TO DOWNSLOPE WARMING EFFECTS. A WEAK
SHORTWAVE MOVING TOWARD THE REGION ON SATURDAY AFTERNOON WILL BRING
WITH IT A PLUME OF LOW-MID LEVEL MOISTURE. COULD SEE A FEW
OROGRAPHIC SNOW SHOWERS OVER THE MOUNTAINS IN THE LATE AFTERNOON AS
THIS WEAK ENERGY AND MOISTURE MOVE OVERHEAD.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 332 AM MST THU NOV 28 2013
VERY DEFINITE PATTERN CHANGE CONTINUES TO BE ADVERTISED IN THE
LONG TERM. LOOKS VERY COLD AND WET FOR NEXT WEEK.
STARTING OFF SATURDAY NIGHT...LOOKS LIKE OUR WIND PRONE AREAS WILL
BE WINDY AS GFS 700MB WINDS ARE UP AROUND 45KTS SATURDAY NIGHT.
AFTER A DECREASE IN WINDS DURING THE DAY SUNDAY...THEY PICK UP
AGAIN SUNDAY NIGHT...THOUGH NOT AS STRONG AS PREVIOUS MODEL RUNS
WERE ADVERTISING. RIGHT NOW...THE NEW GFS WINDS ARE RIGHT AROUND
45-50KTS SUNDAY EVENING INTO MONDAY. CRAIG TO CASPER 700MB HEIGHT
GRADIENT STILL TIGHT THOUGH...RIGHT AROUND 70MTRS...SO IF THIS
HOLDS TRUE...WE WILL PROBABLY NEED SOME WIND HEADLINES FOR THIS
TIME FRAME.
MODELS STILL ADVERTISING A DRASTIC CHANGE IN THE WEATHER TUESDAY
AS A STRONG PACIFIC LOW PRESSURE SYSTEM MOVES INTO THE PACNW.
FRONT DOES NOT MAKE IT INTO SOUTHEAST WYOMING UNTIL WEDNESDAY
MORNING. MODELS CONTINUE TO SHOW THIS FRONT STALLING OVER NORTHERN
COLORADO AND PERSISTING THROUGH THE REMAINDER OF THE WEEK. 700MB
TEMPERATURES ARE QUITE COLD BEHIND THE FRONT. GFS SHOWING -18 TO
-20C WHILE NEW ECMWF RUN SHOWING -16 TO -18C. GOING TO BE QUITE
COLD THROUGH THE REMAINDER OF THE WEEK. HIGHS THURSDAY/FRIDAY MAY
ONLY BE IN THE TEENS WITH LOWS CLOSE TO ZERO AT MANY LOCATIONS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 332 AM MST THU NOV 28 2013
SOME CONCERN FOR THE NORTHERN NEBRASKA PANHANDLE AS LATEST 11-3.9U
SATELLITE IMAGERY SHOWING LOW STRATUS MOVING SOUTHWEST OUT OF
SOUTH DAKOTA. LATEST HRRR MODEL BRINGS IFR CONDITIONS INTO KCDR
AND KEEPS IT IN THROUGH 18Z. WILL BE ADJUSTING THE 12Z KCDR TAF
BASED ON THIS AND THE SATELLITE TRENDS ONCE THE STRATUS GETS CLOSER.
&&
.FIRE WEATHER...
ISSUED AT 332 AM MST THU NOV 28 2013
NO FIRE WEATHER CONCERNS ANTICIPATED THROUGH THE NEAR TERM. MILD AND
DRY CONDITIONS WILL CONTINUE ACROSS THE DISTRICT OVER THE NEXT FEW
DAYS WITH DAYTIME TEMPS AVERAGING IN THE 40S AND 50S DEGREES...WITH
COOLER READINGS OVER THE HIGHER TERRAIN. MINIMUM HUMIDITIES WILL BE
AT OR ABOVE 30 PERCENT EACH AFTERNOON. MODERATE WINDS ARE EXPECTED
ON FRIDAY AND SATURDAY IN THE WIND PRONE REGIONS ALONG AND WEST OF
THE LARAMIE RANGE WITH SUSTAINED SPEEDS BETWEEN 25 AND 40 MPH AND
GUSTS AROUND 50 MPH AT TIMES. A STRONG WEATHER SYSTEM WILL BEGIN TO
TAKE SHAPE LATE THIS WEEKEND INTO THE EARLY PART OF NEXT
WEEK...LIKELY BRINGING STRONGER WINDS...COLDER TEMPERATURES AND AN
INCREASED CHANCE FOR ACCUMULATING SNOWS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RJM
LONG TERM...CLAYCOMB
AVIATION...CLAYCOMB
FIRE WEATHER...RJM
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
1224 PM EST THU NOV 28 2013
.AVIATION...
THE WINDS WILL BE SWINGING TO A NORTHEAST DIRECTION EARLY THIS
AFTERNOON AND REMAIN NORTHEAST THROUGH TONIGHT. THE SPEEDS WILL BE
5 TO 10 KNOTS THIS AFTERNOON INTO TONIGHT AT ALL OF THE TAF
SITES...EXCEPT FOR KAPF TAF SITE WHERE THE SPEEDS WILL DROP DOWN
TO 3 KNOTS AFTER 23Z TONIGHT. SOME CLOUDS FROM THE ATLANTIC WATERS
WILL WORK INTO KFLL AND KPBI TAF STIES THIS AFTERNOON...BUT SHOULD
REMAIN IN THE VFR CONDITIONS ALONG WITH THE VIS IN THE VFR
CONDITIONS. REST OF THE TAF SITES OVER SOUTH FLORIDA WILL ALSO
REMAIN IN THE VFR CONDITIONS FOR THE SKY AND VIS.
&&
.AVIATION...54/BNB
.PREV DISCUSSION... /ISSUED 951 AM EST THU NOV 28 2013/
UPDATE...
OUTSIDE OF A FEW MINOR TWEAKS BASED ON THE LATEST OBSERVATIONS
AROUND THE LOCAL AREA...NO MAJOR UPDATES WERE NECESSARY. THE
WINDS OVER LAKE OKEECHOBEE WERE SLIGHTLY HIGHER THAN ORIGINALLY
EXPECTED DUE TO STRONGER WINDS MIXING DOWN OVER THE WARMER LAKE
WATERS...WHICH HAS PROMPTED A SHORT-FUSED ADVISORY. THESE WINDS
SHOULD TREND DOWN THROUGH THE LATE MORNING AND AFTERNOON PERIOD AS
THE GRADIENT RELAXES.
THE MAIN STORY THIS MORNING HAS BEEN THE COOL TEMPERATURES...WHICH
MARKS THE COOLEST MORNING OF THE SEASON FOR SOUTH FLORIDA.
BRIGHTON IN NORTHERN GLADES COUNTY BRIEFLY DROPPED TO 36 DEGREES
..WHICH WAS THE COLDEST RECORDED TEMPERATURE IN OUR LOCAL AREA
TODAY. ELSEWHERE...TEMPERATURES RANGED FROM THE UPPER 30S FROM THE
INTERIOR AREAS (PALMDALE TO IMMOKALEE) TO THE LOWER 50S ALONG THE
COAST IN MIAMI-DADE COUNTY. THE MORNING SOUNDING AT MIAMI
REFLECTED THIS COOL AIR AT THE SURFACE BELOW A STRONG LOW-LEVEL
INVERSION AROUND 1700 FT...THEN TOPPED WITH A SUBSTANTIAL AMOUNT
OF DRY AIR ABOVE 3500 FT (PWAT OF .5"). THE LATEST RUC ANALYSIS
HAS LINED UP WELL WITH THE CURRENT SYNOPTIC PATTERN AND GENERALLY
INDICATES THE COLD AIR ADVECTION COMING TO AN END LATER TODAY AS
THE LOW-LEVEL FLOW QUICKLY SHIFTS TO THE NORTHEAST. AFTERNOON
HIGHS ARE FORECAST TO CLIMB INTO THE LOWER 70S.
&&
.UPDATED...AG
PREV DISCUSSION... /ISSUED 645 AM EST THU NOV 28 2013/
AVIATION...VFR WILL PREVAIL. SKIES WILL BE MOSTLY CLEAR AT KAPF
THROUGH THE PERIOD. FOR THE EAST COAST, EXPECT SCT-BKN STRATO CU
TO INCREASE LATER TODAY...AT AROUND 5K FT. BRIEF MVFR CIGS WILL
CONTINUE IN MIAMI-DADE OVER THE NEXT HOUR BUT ARE EXPECTED TO
IMPROVE. MOISTURE LOOKS TOO SHALLOW TO ADD ANY SHOWER MENTION.
WINDS WILL PREVAIL NW AT NEAR 10 KT. GFS/NAM MOS LIKELY BRINGING
WINDS OUT OF THE NE TOO QUICKLY ATLANTIC TERMINALS. HRRR LOOKS TO
HAVE THE RIGHT IDEA, DELAYING NE WINDS UNTIL 18-19Z. /GREGORIA
&&
PREV DISCUSSION... /ISSUED 406 AM EST THU NOV 28 2013/
DISCUSSION...
TEMPERATURES IN THE LOW TO MID 50S ARE SEEN THIS MORNING ALONG
THE EAST COAST WITH MID TO UPPER 40S ACROSS THE INTERIOR WITH
BRISK NORTHERLY WINDS. WINDS SHOULD BEGIN TO VEER MORE TO THE
NORTHEAST THROUGH THE DAY ALLOWING MORE OF A MARITIME INFLUENCE
AND WEAK MOISTURE RETURN ACROSS THE AREA PARTICULARLY FOR THE
EASTERN HALF OF THE AREA. HOWEVER...GENERALLY RAIN FREE WEATHER
SHOULD PREVAIL THROUGH THE DAY.
NORTHEAST FLOW SHOULD THEN PERSIST THROUGH THE WEEKEND AS HIGH
PRESSURE REMAINS CENTERED JUST OFF THE CAROLINA COAST. THIS FLOW
REGIME WILL ALLOW FOR A FEW SHOWERS TO STREAM ACROSS THE ATLANTIC
WATERS AND INTO THE EAST COAST METRO AREAS DURING THIS TIME FRAME
ALONG WITH SLIGHTLY WARMER TEMPERATURES.
BY EARLY NEXT WEEK...A WEAK H5 SHORTWAVE IS FORECAST TO SURGE TO
THE SOUTHEAST ACROSS THE DEEP SOUTH AND INTO NORTHERN FLORIDA. AS
IT DOES...AN ASSOCIATED SURFACE LOW ACROSS THE WESTERN ATLANTIC
WILL PULL TO THE NORTHEAST WRAPPING SOME DEEPER MOISTURE ACROSS
THE FLORIDA PENINSULA RESULTING IN SLIGHT CHANCES FOR SHOWERS ON
MONDAY. AS THE LOW CONTINUES TO MOVE ON...IT WILL SWING A COLD
FRONT THROUGH THE AREA LATE MONDAY INTO TUESDAY WITH A RETURN TO
DRIER CONDITIONS WITH MORE NORTHWEST TO NORTHERLY FLOW AND COOLER
TEMPERATURES.
MARINE...
FRESH NORTH TO NORTHEASTERLY WINDS WILL PREVAIL TODAY AND THROUGH
THE WEEKEND WITH HIGH PRESSURE SITUATED ACROSS THE WESTERN
ATLANTIC. SEAS ACROSS THE GULF WATERS WILL BEGIN TO SUBSIDE
THROUGH THE DAY AS WINDS BECOME MORE OFFSHORE. ACROSS THE
ATLANTIC...SEAS SHOULD REMAIN NEAR ADVISORY LEVELS THROUGH
SATURDAY BEFORE WINDS SUBSIDE SLIGHTLY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 65 77 68 / - - 10 10
FORT LAUDERDALE 73 67 79 71 / - - 10 10
MIAMI 73 65 79 69 / - - 10 10
NAPLES 73 56 81 60 / - - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-
LAKE OKEECHOBEE-WATERS FROM DEERFIELD BEACH TO OCEAN REEF,
FL EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE
BAHAMAS.
SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING
FROM 20 NM TO 60 NM.
GM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...57/DG
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
230 PM CST THU NOV 28 2013
.DISCUSSION...
306 AM CST
THE PRIMARY FORECAST CONCERNS ARE CENTERED ON CLOUD COVER AND
TEMPERATURES THROUGH THE WEEKEND AND THEN CHANCES FOR PRECIPITATION
NEXT WEEK IN WHAT APPEARS TO POSSIBLY BE AN UNSETTLED
PATTERN...ALTHOUGH A HIGH DEGREE OF UNCERTAINTY.
ONE MORE SHORT WAVE IS DIVING SOUTHEAST ACROSS THE GREAT LAKES THIS
THANKSGIVING MORNING IN WHAT HAS BEEN A LITERAL PARADE OF THESE
COLD-AIR-REINFORCING SYSTEMS. A 1017MB SURFACE LOW REFLECTION ACROSS
IA WILL TRANSLATE EAST THIS MORNING AND WEAKEN AS IT DOES SUCH.
MORNING CLOUDS IN PLACE WERE DEVELOPED WITHIN THE WARM AIR ADVECTION
ENVELOPE OF THIS SYSTEM AND AS SUCH HAVE BASES MAINLY ABOVE 5000
FT...SO BELIEVE THEY WILL VACATE BY AFTERNOON ACROSS THE WESTERN AND
SOUTHERN FORECAST AREA GIVEN THE CLOUD-BEARING WIND FLOW. LOW-LEVEL
LAPSE RATES ARE MODESTLY STEEP BEHIND THE SYSTEM WITH SOME MARGINAL
SATURATION FORECAST AT THE TOP OF THE MIXED LAYER...SO LIKELY SOME
SCATTERED STRATOCU WILL CONTINUE. ALL-IN-ALL...EXPECTING SOME SUN
LATE THIS MORNING AND AFTERNOON. GIVEN THE 850MB AND 925MB FORECAST
TEMPS BY THE RAP AND NAM THIS AFTERNOON...WE ONCE AGAIN ARE IN THE
BOTTOM TENTH PERCENTILE FOR THIS TIME OF YEAR. THIS FAVORS HIGHS IN
THE LOWER TO MID 30S. SEE THE CLIMATE DISCUSSION BELOW FOR MORE ON
WHERE THIS STACKS UP FOR THANKSGIVING DAYS.
AS A CANADIAN SURFACE HIGH MOVES OVERHEAD TONIGHT TEMPERATURES
SHOULD RADIATE QUICKLY THIS EVE...EVEN IF IT DOES TAKE A FEW HOURS
AFTER SUNSET TO DIMINISH THE LINGERING STRATOCU. HAVE MID AND EVEN
PATCHY LOWER TEENS IN OUTLYING AREAS. AS THE WIND FIELD OVER LAKE MI
SHIFTS MORE NE TONIGHT IMMEDIATELY AHEAD OF THE HIGH CENTER...A LAKE
PLUME OF AT LEAST CLOUDS LOOKS LIKELY INTO NORTHWEST INDIANA AND
POSSIBLY NORTHEAST ILLINOIS. LAKE-INDUCED EQUILIBRIUM LEVELS AROUND
4500 FT FORECAST BY THE NAM SEEM A LITTLE SHALLOW FOR PRECIP AND ANY
PRONOUNCED CONVERGENCE IS UNLIKELY. HAVE THUS ONLY ADDED A LOW
CHANCE FOR SOME LIGHT SNOW IN NORTHWEST IN/FAR SOUTHEAST COOK COUNTY
LATE TONIGHT AS WELL AS BUMPED UP CLOUD COVER.
A MORE ZONAL PATTERN WILL MOVE OVER BY LATER FRIDAY INTO SATURDAY
BRINGING MODERATING TEMPERATURES. THERE IS A FAIR AMOUNT OF SPREAD
IN THE ENVELOPE OF GUIDANCE SOLUTIONS FOR HOW WARM SATURDAY WILL
BE...AND POTENTIAL CLOUD COVER LIKELY HAS QUITE A BIT TO DO WITH
THAT. THIS TIME OF YEAR SOUTHERLY LOW-LEVEL FLOW AFTER A COLD AIR
MASS CAN READILY BECOME "CONTAMINATED" WITH SATURATION/CLOUDS.
CLIMATOLOGY OF THE 850MB AND 925MB TEMPERATURES WOULD FAVOR MID AND
MAYBE EVEN UPPER 40S...BUT THAT WARM CURRENTLY SEEMS UNLIKELY WITH
AT LEAST SOME POTENTIAL FOR CLOUDS AND NOT THE STRONGEST OF WARM AIR
ADVECTION SIGNALS. THE HEART OF THE SYSTEM IS OVER THE NORTHERN
GREAT LAKES...SO FORCING AND SATURATION REMAINS MINIMAL OVER THE
AREA. SO HAVE NO POPS AT THIS TIME.
NEXT WEEK THE UNCERTAINTY REALLY STARTS TO RAMP UP BY MIDWEEK AFTER
WHAT IS BECOMING A MORE FAVORED DRY SUNDAY AND MONDAY. ALTHOUGH MUCH
LIKE SATURDAY...TEMPERATURE CONFIDENCE IS FAIRLY LOW GIVEN CLOUD
POTENTIAL. IF CLOUDS ARE REMAINING INTO SUNDAY MORNING THEY VERY
WELL COULD STICK AROUND ALL THE WAY THROUGH MONDAY NIGHT AS SURFACE
PRESSURES ARE FORECAST TO BASICALLY REMAIN THE SAME...I.E. LITTLE
ADVECTION. THE LONG ADVERTISED UPPER TROUGH ACROSS THE WEST COAST
LOOKS TO EVOLVE IN THE BEGINNING OF THE WEEK AND FORCE DOWNSTREAM
RIDGING AND SOUTHWEST FLOW ALOFT. THIS TROUGH SHOULD PACK QUITE A
PUNCH OF COLD AIR INTO THE NORTHERN ROCKIES AND PLAINS...BUT THE
MAIN BAROCLINIC ZONE DURING MIDWEEK LOOKS TO REMAIN TO THE NORTHWEST
AND IF THAT IS THE CASE THEN ANY HEAVY WINTER PRECIP SHOULD AS WELL
DURING MIDWEEK...BUT AGAIN CONFIDENCE IS LOW. ENERGY THAT TRANSLATES
EAST FROM THIS TROUGH APPEARS TO BE IN PARTS AND THUS MULTIPLE
CHANCES FOR PRECIP LOOK TO BE THE CASE ACROSS THE GREAT LAKES AND
CORN BELT REGIONS DURING THE DEC 3-8 PERIOD. NIGHTTIME TEMPERATURES
SHOULD BE MORE NEAR NORMAL OR EVEN ABOVE NORMAL GIVEN CLOUD
COVER DURING MIDWEEK...BUT DAYTIME HIGHS COULD BE ANYWHERE IN A
LARGE SPECTRUM OF SOLUTIONS DEPENDING ON STRENGTH OF SOUTHERLY
FLOW AND WHEN LOW PASSAGES OCCUR. THOSE ARE BOTH VARIABLES DIFFICULT
TO LOCK DOWN IN A FORECAST PATTERN OF A BROAD TROUGH IN THE WEST.
MTF
&&
.CLIMATE...
306 AM CST
THE FORECAST HIGH TODAY FOR CHICAGO (O`HARE) IS 33 WHICH WOULD TIE
MULTIPLE THANKSGIVINGS IN THE PAST TWO DECADES FOR A COOL
HIGH...THE LAST BEING 2007. HOWEVER IF THE MERCURY STAYS BELOW
THAT...IT WOULD BE THE COLDEST HIGH TEMPERATURE ON THANKSGIVING IN
CHICAGO SINCE 1989.
SIMILARLY FOR ROCKFORD...THE 31 DEGREE FORECAST HIGH WOULD BE THE
COOLEST THANKSGIVING HIGH SINCE 1995 AND IF IT STAYS BELOW THAT IT
WOULD BE THE COOLEST SINCE 1989.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WEST NORTHWEST WIND BECOMING MORE NORTHWEST THIS AFTERNOON.
* VFR CEILINGS EXPECTED THIS AFTERNOON...WITH A CHANCE FOR A BRIEF
PERIOD OF MVFR CEILINGS EARLY THIS EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
AN APPROACHING COLD FRONT WILL PUSH ACROSS THE TERMINALS OVER THE
NEXT 1-2 HOURS WITH WEST SOUTHWEST WINDS TURNING TO THE
NORTHWEST...AND A RETURN OF VFR CEILINGS. THIS CLOUD COVER CAN BE
OBSERVED MOVING SOUTHEAST ACROSS EASTERN IOWA AND SOUTHERN
WISCONSIN...WITH DISTANCE SPEED TOOL BRINGING THIS TO RFD BY 19Z
AND TO ORD BY 20Z. SHORT TERM GUIDANCE CONTINUES TO INDICATE THE
POSSIBILITY OF MVFR CEILINGS LATER THIS EVENING...AND CANNOT RULE
THIS OUT WITH COLDER AIR MOVING ACROSS THE REGION. SO HAVE SHOWED
THIS POSSIBILITY IN THE TAF. VFR OR MVFR CEILINGS WILL NOT BE LONG
LASTING THIS EVENING...WITH THIS AREA OF CLOUD COVER EXPECTED TO
QUICKLY EXIT THE TERMINALS AND ONLY HIGH LEVEL CLOUDS TO THEN MOVE
OVER THE TERMINALS THROUGH THE REMAINDER OF THE FORECAST PERIOD.
WINDS WILL DIMINISH TONIGHT AND EVEN BECOME CALM OR LIGHT AND
VARIABLE AS HIGH PRESSURE MOVES OVERHEAD...BUT THEN INCREASE OUT
OF THE SOUTHEAST BY MID DAY FRIDAY.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
* LOW MEDIUM CONFIDENCE WITH MVFR POTENTIAL EARLY THIS EVENING.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...VFR.
SUNDAY AND MONDAY...MVFR POSSIBLE,
TUESDAY...VFR.
WEDNESDAY...CHANCE SHRA...MVFR POSSIBLE.
MDB
&&
.MARINE...
228 PM CST
A BROAD RIDGE OF HIGH PRESSURE CONTINUES TO BE CENTERED ACROSS THE
TENN VALLEY. WITH THE HIGH PRESSURE CENTERED SOUTH OF LAKE
MICHIGAN...AND A WEAK LOW PRESSURE FLOATING SOUTHEAST ACROSS THE
NORTHERN PORTIONS OF LAKE MICHIGAN THIS AFTERNOON...WINDS FOR THE
SOUTHERN TWO-THIRDS OF LAKE MICHIGAN HAVE REMAINED WEST/NORTHWEST
WHILE THE FAR NORTHERN SECTION IS EASTERLY. AT TIMES THE GRADIENT
HAS BEEN TIGHT ENOUGH TO PRODUCE GUSTS TO 25KT NEAR THE
STRAITS...HOWEVER IN GENERAL THE GRADIENT IS EXPECTED TO BE
DIMINISHING.
HIGH PRESSURE WILL BE LIFTING NORTHEAST ACROSS THE NORTHEASTERN
CONUS...WHICH WILL ALLOW WINDS TO BACK TO THE SOUTHWEST/SOUTH FRIDAY
AFTERNOON. THE GRADIENT DOES RAMP UP ALONG THE WESTERN EDGE OF THE
HIGH PRESSURE FRIDAY NIGHT/SATURDAY. GUIDANCE HAS INDICATED THAT
SOUTHERLY GUSTS MAY APPROACH 30KT...AND OCCASIONAL GALE FORCE GUSTS
MAY OCCUR MAINLY FOR THE OPEN WATERS.
A LOW PRESSURE WILL DEVELOP ACROSS THE NORTHERN PLAINS/SOUTHCENTRAL
CANADA LATE FRI NIGHT...THEN STEADILY STRENGTHEN AS IT SLIDES EAST
TOWARDS JAMES BAY SATURDAY AFTN. THIS MAY HELP TO PROLONG HIGHER
GUSTS TO NEAR GALES FOR THE FAR NORTHERN PORTIONS OF LAKE MICHIGAN
SAT. MEANWHILE FURTHER SOUTH THE GRADIENT WILL DIMINISH...WITH WINDS
SHIFTING TO THE WEST THEN NORTH BEHIND A FRONTAL BOUNDARY SUN.
THE GRADIENT DOES APPEAR TO REMAIN MINIMAL SUN NGT...WITH WEAK HIGH
PRESSURE SLIDING NORTHEAST ACROSS NORTHEAST ONTARIO. THIS WILL ALLOW
WINDS TO BECOME EASTERLY FOR EARLY NEXT WEEK...BUT WITH THE LACK OF
ANY SIGNIFICANT GRADIENT...WINDS SHOULD REMAIN ARND 10-20KT FOR
MON/TUE. THEN FOR THE MIDDLE OF NEXT WEEK FORECAST MODELS ARE
INDICATING AN AREA OF LOW PRESSURE TO INTENSIFY ACROSS THE UPPER
MIDWEST AND PIVOT EAST TOWARDS THE NORTHERN GREAT LAKES. THEN YET
ANOTHER LOW PRESSURE TO WATCH LATER IN THE WEEK...WHICH COULD
PROVIDE PROLONGED PERIOD OF SOUTH/SOUTHWEST WINDS AND BUILDING WAVES
FOR THE NORTHERN PORTIONS OF LAKE MICHIGAN TUE NIGHT THROUGH THUR.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
147 PM CST THU NOV 28 2013
.DISCUSSION...
306 AM CST
THE PRIMARY FORECAST CONCERNS ARE CENTERED ON CLOUD COVER AND
TEMPERATURES THROUGH THE WEEKEND AND THEN CHANCES FOR PRECIPITATION
NEXT WEEK IN WHAT APPEARS TO POSSIBLY BE AN UNSETTLED
PATTERN...ALTHOUGH A HIGH DEGREE OF UNCERTAINTY.
ONE MORE SHORT WAVE IS DIVING SOUTHEAST ACROSS THE GREAT LAKES THIS
THANKSGIVING MORNING IN WHAT HAS BEEN A LITERAL PARADE OF THESE
COLD-AIR-REINFORCING SYSTEMS. A 1017MB SURFACE LOW REFLECTION ACROSS
IA WILL TRANSLATE EAST THIS MORNING AND WEAKEN AS IT DOES SUCH.
MORNING CLOUDS IN PLACE WERE DEVELOPED WITHIN THE WARM AIR ADVECTION
ENVELOPE OF THIS SYSTEM AND AS SUCH HAVE BASES MAINLY ABOVE 5000
FT...SO BELIEVE THEY WILL VACATE BY AFTERNOON ACROSS THE WESTERN AND
SOUTHERN FORECAST AREA GIVEN THE CLOUD-BEARING WIND FLOW. LOW-LEVEL
LAPSE RATES ARE MODESTLY STEEP BEHIND THE SYSTEM WITH SOME MARGINAL
SATURATION FORECAST AT THE TOP OF THE MIXED LAYER...SO LIKELY SOME
SCATTERED STRATOCU WILL CONTINUE. ALL-IN-ALL...EXPECTING SOME SUN
LATE THIS MORNING AND AFTERNOON. GIVEN THE 850MB AND 925MB FORECAST
TEMPS BY THE RAP AND NAM THIS AFTERNOON...WE ONCE AGAIN ARE IN THE
BOTTOM TENTH PERCENTILE FOR THIS TIME OF YEAR. THIS FAVORS HIGHS IN
THE LOWER TO MID 30S. SEE THE CLIMATE DISCUSSION BELOW FOR MORE ON
WHERE THIS STACKS UP FOR THANKSGIVING DAYS.
AS A CANADIAN SURFACE HIGH MOVES OVERHEAD TONIGHT TEMPERATURES
SHOULD RADIATE QUICKLY THIS EVE...EVEN IF IT DOES TAKE A FEW HOURS
AFTER SUNSET TO DIMINISH THE LINGERING STRATOCU. HAVE MID AND EVEN
PATCHY LOWER TEENS IN OUTLYING AREAS. AS THE WIND FIELD OVER LAKE MI
SHIFTS MORE NE TONIGHT IMMEDIATELY AHEAD OF THE HIGH CENTER...A LAKE
PLUME OF AT LEAST CLOUDS LOOKS LIKELY INTO NORTHWEST INDIANA AND
POSSIBLY NORTHEAST ILLINOIS. LAKE-INDUCED EQUILIBRIUM LEVELS AROUND
4500 FT FORECAST BY THE NAM SEEM A LITTLE SHALLOW FOR PRECIP AND ANY
PRONOUNCED CONVERGENCE IS UNLIKELY. HAVE THUS ONLY ADDED A LOW
CHANCE FOR SOME LIGHT SNOW IN NORTHWEST IN/FAR SOUTHEAST COOK COUNTY
LATE TONIGHT AS WELL AS BUMPED UP CLOUD COVER.
A MORE ZONAL PATTERN WILL MOVE OVER BY LATER FRIDAY INTO SATURDAY
BRINGING MODERATING TEMPERATURES. THERE IS A FAIR AMOUNT OF SPREAD
IN THE ENVELOPE OF GUIDANCE SOLUTIONS FOR HOW WARM SATURDAY WILL
BE...AND POTENTIAL CLOUD COVER LIKELY HAS QUITE A BIT TO DO WITH
THAT. THIS TIME OF YEAR SOUTHERLY LOW-LEVEL FLOW AFTER A COLD AIR
MASS CAN READILY BECOME "CONTAMINATED" WITH SATURATION/CLOUDS.
CLIMATOLOGY OF THE 850MB AND 925MB TEMPERATURES WOULD FAVOR MID AND
MAYBE EVEN UPPER 40S...BUT THAT WARM CURRENTLY SEEMS UNLIKELY WITH
AT LEAST SOME POTENTIAL FOR CLOUDS AND NOT THE STRONGEST OF WARM AIR
ADVECTION SIGNALS. THE HEART OF THE SYSTEM IS OVER THE NORTHERN
GREAT LAKES...SO FORCING AND SATURATION REMAINS MINIMAL OVER THE
AREA. SO HAVE NO POPS AT THIS TIME.
NEXT WEEK THE UNCERTAINTY REALLY STARTS TO RAMP UP BY MIDWEEK AFTER
WHAT IS BECOMING A MORE FAVORED DRY SUNDAY AND MONDAY. ALTHOUGH MUCH
LIKE SATURDAY...TEMPERATURE CONFIDENCE IS FAIRLY LOW GIVEN CLOUD
POTENTIAL. IF CLOUDS ARE REMAINING INTO SUNDAY MORNING THEY VERY
WELL COULD STICK AROUND ALL THE WAY THROUGH MONDAY NIGHT AS SURFACE
PRESSURES ARE FORECAST TO BASICALLY REMAIN THE SAME...I.E. LITTLE
ADVECTION. THE LONG ADVERTISED UPPER TROUGH ACROSS THE WEST COAST
LOOKS TO EVOLVE IN THE BEGINNING OF THE WEEK AND FORCE DOWNSTREAM
RIDGING AND SOUTHWEST FLOW ALOFT. THIS TROUGH SHOULD PACK QUITE A
PUNCH OF COLD AIR INTO THE NORTHERN ROCKIES AND PLAINS...BUT THE
MAIN BAROCLINIC ZONE DURING MIDWEEK LOOKS TO REMAIN TO THE NORTHWEST
AND IF THAT IS THE CASE THEN ANY HEAVY WINTER PRECIP SHOULD AS WELL
DURING MIDWEEK...BUT AGAIN CONFIDENCE IS LOW. ENERGY THAT TRANSLATES
EAST FROM THIS TROUGH APPEARS TO BE IN PARTS AND THUS MULTIPLE
CHANCES FOR PRECIP LOOK TO BE THE CASE ACROSS THE GREAT LAKES AND
CORN BELT REGIONS DURING THE DEC 3-8 PERIOD. NIGHTTIME TEMPERATURES
SHOULD BE MORE NEAR NORMAL OR EVEN ABOVE NORMAL GIVEN CLOUD
COVER DURING MIDWEEK...BUT DAYTIME HIGHS COULD BE ANYWHERE IN A
LARGE SPECTRUM OF SOLUTIONS DEPENDING ON STRENGTH OF SOUTHERLY
FLOW AND WHEN LOW PASSAGES OCCUR. THOSE ARE BOTH VARIABLES DIFFICULT
TO LOCK DOWN IN A FORECAST PATTERN OF A BROAD TROUGH IN THE WEST.
MTF
&&
.CLIMATE...
306 AM CST
THE FORECAST HIGH TODAY FOR CHICAGO (O`HARE) IS 33 WHICH WOULD TIE
MULTIPLE THANKSGIVINGS IN THE PAST TWO DECADES FOR A COOL
HIGH...THE LAST BEING 2007. HOWEVER IF THE MERCURY STAYS BELOW
THAT...IT WOULD BE THE COLDEST HIGH TEMPERATURE ON THANKSGIVING IN
CHICAGO SINCE 1989.
SIMILARLY FOR ROCKFORD...THE 31 DEGREE FORECAST HIGH WOULD BE THE
COOLEST THANKSGIVING HIGH SINCE 1995 AND IF IT STAYS BELOW THAT IT
WOULD BE THE COOLEST SINCE 1989.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WEST NORTHWEST WIND BECOMING MORE NORTHWEST THIS AFTERNOON.
* VFR CEILINGS EXPECTED THIS AFTERNOON...WITH A CHANCE FOR A BRIEF
PERIOD OF MVFR CEILINGS EARLY THIS EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
AN APPROACHING COLD FRONT WILL PUSH ACROSS THE TERMINALS OVER THE
NEXT 1-2 HOURS WITH WEST SOUTHWEST WINDS TURNING TO THE
NORTHWEST...AND A RETURN OF VFR CEILINGS. THIS CLOUD COVER CAN BE
OBSERVED MOVING SOUTHEAST ACROSS EASTERN IOWA AND SOUTHERN
WISCONSIN...WITH DISTANCE SPEED TOOL BRINGING THIS TO RFD BY 19Z
AND TO ORD BY 20Z. SHORT TERM GUIDANCE CONTINUES TO INDICATE THE
POSSIBILITY OF MVFR CEILINGS LATER THIS EVENING...AND CANNOT RULE
THIS OUT WITH COLDER AIR MOVING ACROSS THE REGION. SO HAVE SHOWED
THIS POSSIBILITY IN THE TAF. VFR OR MVFR CEILINGS WILL NOT BE LONG
LASTING THIS EVENING...WITH THIS AREA OF CLOUD COVER EXPECTED TO
QUICKLY EXIT THE TERMINALS AND ONLY HIGH LEVEL CLOUDS TO THEN MOVE
OVER THE TERMINALS THROUGH THE REMAINDER OF THE FORECAST PERIOD.
WINDS WILL DIMINISH TONIGHT AND EVEN BECOME CALM OR LIGHT AND
VARIABLE AS HIGH PRESSURE MOVES OVERHEAD...BUT THEN INCREASE OUT
OF THE SOUTHEAST BY MID DAY FRIDAY.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
* LOW MEDIUM CONFIDENCE WITH MVFR POTENTIAL EARLY THIS EVENING.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...VFR.
SUNDAY AND MONDAY...MVFR POSSIBLE,
TUESDAY...VFR.
WEDNESDAY...CHANCE SHRA...MVFR POSSIBLE.
MDB
&&
.MARINE...
221 AM CST
THE MAIN FOCUS OF THE FORECAST CONTINUES TO BE THE POTENTIAL FOR
GALE FORCE WINDS LATE FRIDAY NIGHT THROUGH MIDDAY/EARLY AFTERNOON
SATURDAY...MAINLY ACROSS THE NORTH HALF OF THE LAKE.
CURRENTLY...SURFACE LOW PRESSURE CONTINUES TO DEEPEN AS IT MOVES
NORTHWARD INTO EASTERN QUEBEC AND NEWFOUNDLAND. HIGH PRESSURE
RIDGING IS CROSSING LAKE MICHIGAN EARLY THIS MORNING WITH A WEAK
AREA OF LOW PRESSURE OVER WESTERN MINNESOTA AND NORTHWEST IOWA.
THIS LOW WILL MOVE ACROSS NORTHERN LAKE MICHIGAN LATER TODAY AND
THIS EVENING. WINDS HAVE TURNED WEST AND SOUTHWEST THANKS TO THE
PASSAGE OF THE RIDGE AXIS WITH SPEEDS DIMINISHING BUT THEY WILL
INCREASE SOMEWHAT AS THE LOW CROSSES THE AREA LATER TODAY. A
NARROW CORRIDOR OF OFFSHORE SOUTHEASTERLY WINDS IS OCCURRING ALONG
THE MICHIGAN SHORE BUT WILL DIMINISH THROUGH MID MORNING. WINDS
ACROSS FAR NORTHERN LAKE MICHIGAN WILL BE TRICKY AS THE LOW CENTER
IS EXPECTED TO CROSS THIS AREA THIS AFTERNOON. THIS WILL LIKELY
LEAD TO AN EASTERLY SURFACE FLOW OVER FAR NORTHERN LAKE MICHIGAN
LATER THIS MORNING AND THIS AFTERNOON...WHILE THE REST OF THE LAKE
SEES WEST TO SOUTHWEST WINDS. A COOL FRONTAL BOUNDARY WILL CROSS
THE LAKE LATER TODAY TURNING WINDS TO THE NORTHWEST. HIGH PRESSURE
WILL SPREAD IN BEHIND THE FRONT AND STRENGTHEN AS IT CROSSES THE
LAKE FRIDAY BEFORE SHIFTING TO THE EAST. THIS WILL TURN WINDS BACK
TO THE SOUTH BY FRIDAY AFTERNOON WITH RATHER LIGHT SPEEDS.
THE HIGH WILL CONTINUE TO STRENGTHEN AS IT MOVES ACROSS THE NORTHEAST
U.S. WHILE A CLIPPER DROPS SOUTHEAST ACROSS WESTERN ONTARIO JUST
NORTH OF LAKE SUPERIOR SATURDAY. THE PRESSURE GRADIENT WILL TIGHTEN
BETWEEN THESE TWO SYSTEMS LEADING TO STRONG SOUTH TO SOUTHWEST WINDS
LATE FRIDAY NIGHT AND SATURDAY MORNING. THE STRONGEST SPEEDS WILL
OCCUR ACROSS NORTHERN PORTIONS OF THE LAKE. WILL HOLD WINDS TO 30 KT
FOR NOW WITH THE STRONGEST WINDS NORTH...BUT AM CONCERNED THAT AN
INCREASE TO GALES MAY BE NEEDED. THIS SYSTEM IS NOT TOO UNLIKE
SEVERAL WHICH WE SAW EARLIER THIS FALL THAT FEATURED SURFACE LOWS
PASSING TO THE NORTH AND WINDS THAT WERE HIGHER THAN EXPECTED. THIS
MAY NOT BE THE CASE WITH THIS PARTICULAR SYSTEM BUT IT IS WORTH
NOTING GIVEN THAT UNSTABLE CONDITIONS WILL BE IN PLACE ACROSS THE
LAKE SIMILAR TO THESE EARLIER SYSTEMS. A COLD FRONT CROSSES THE
LAKE SATURDAY AFTERNOON ALLOWING WINDS TO DROP OFF SATURDAY
EVENING. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE REGION
SUNDAY AND CONTINUE TO KEEP LIGHTER WINDS IN PLACE THROUGH
TUESDAY. FORECAST CONFIDENCE DROPS OFF BY WEDNESDAY BUT IT DOES
APPEAR THAT A MORE ACTIVE PATTERN WILL BE SETTING UP BRINGING
INCREASING CHANCES FOR STRONGER WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1218 PM CST THU NOV 28 2013
.DISCUSSION...
306 AM CST
THE PRIMARY FORECAST CONCERNS ARE CENTERED ON CLOUD COVER AND
TEMPERATURES THROUGH THE WEEKEND AND THEN CHANCES FOR PRECIPITATION
NEXT WEEK IN WHAT APPEARS TO POSSIBLY BE AN UNSETTLED
PATTERN...ALTHOUGH A HIGH DEGREE OF UNCERTAINTY.
ONE MORE SHORT WAVE IS DIVING SOUTHEAST ACROSS THE GREAT LAKES THIS
THANKSGIVING MORNING IN WHAT HAS BEEN A LITERAL PARADE OF THESE
COLD-AIR-REINFORCING SYSTEMS. A 1017MB SURFACE LOW REFLECTION ACROSS
IA WILL TRANSLATE EAST THIS MORNING AND WEAKEN AS IT DOES SUCH.
MORNING CLOUDS IN PLACE WERE DEVELOPED WITHIN THE WARM AIR ADVECTION
ENVELOPE OF THIS SYSTEM AND AS SUCH HAVE BASES MAINLY ABOVE 5000
FT...SO BELIEVE THEY WILL VACATE BY AFTERNOON ACROSS THE WESTERN AND
SOUTHERN FORECAST AREA GIVEN THE CLOUD-BEARING WIND FLOW. LOW-LEVEL
LAPSE RATES ARE MODESTLY STEEP BEHIND THE SYSTEM WITH SOME MARGINAL
SATURATION FORECAST AT THE TOP OF THE MIXED LAYER...SO LIKELY SOME
SCATTERED STRATOCU WILL CONTINUE. ALL-IN-ALL...EXPECTING SOME SUN
LATE THIS MORNING AND AFTERNOON. GIVEN THE 850MB AND 925MB FORECAST
TEMPS BY THE RAP AND NAM THIS AFTERNOON...WE ONCE AGAIN ARE IN THE
BOTTOM TENTH PERCENTILE FOR THIS TIME OF YEAR. THIS FAVORS HIGHS IN
THE LOWER TO MID 30S. SEE THE CLIMATE DISCUSSION BELOW FOR MORE ON
WHERE THIS STACKS UP FOR THANKSGIVING DAYS.
AS A CANADIAN SURFACE HIGH MOVES OVERHEAD TONIGHT TEMPERATURES
SHOULD RADIATE QUICKLY THIS EVE...EVEN IF IT DOES TAKE A FEW HOURS
AFTER SUNSET TO DIMINISH THE LINGERING STRATOCU. HAVE MID AND EVEN
PATCHY LOWER TEENS IN OUTLYING AREAS. AS THE WIND FIELD OVER LAKE MI
SHIFTS MORE NE TONIGHT IMMEDIATELY AHEAD OF THE HIGH CENTER...A LAKE
PLUME OF AT LEAST CLOUDS LOOKS LIKELY INTO NORTHWEST INDIANA AND
POSSIBLY NORTHEAST ILLINOIS. LAKE-INDUCED EQUILIBRIUM LEVELS AROUND
4500 FT FORECAST BY THE NAM SEEM A LITTLE SHALLOW FOR PRECIP AND ANY
PRONOUNCED CONVERGENCE IS UNLIKELY. HAVE THUS ONLY ADDED A LOW
CHANCE FOR SOME LIGHT SNOW IN NORTHWEST IN/FAR SOUTHEAST COOK COUNTY
LATE TONIGHT AS WELL AS BUMPED UP CLOUD COVER.
A MORE ZONAL PATTERN WILL MOVE OVER BY LATER FRIDAY INTO SATURDAY
BRINGING MODERATING TEMPERATURES. THERE IS A FAIR AMOUNT OF SPREAD
IN THE ENVELOPE OF GUIDANCE SOLUTIONS FOR HOW WARM SATURDAY WILL
BE...AND POTENTIAL CLOUD COVER LIKELY HAS QUITE A BIT TO DO WITH
THAT. THIS TIME OF YEAR SOUTHERLY LOW-LEVEL FLOW AFTER A COLD AIR
MASS CAN READILY BECOME "CONTAMINATED" WITH SATURATION/CLOUDS.
CLIMATOLOGY OF THE 850MB AND 925MB TEMPERATURES WOULD FAVOR MID AND
MAYBE EVEN UPPER 40S...BUT THAT WARM CURRENTLY SEEMS UNLIKELY WITH
AT LEAST SOME POTENTIAL FOR CLOUDS AND NOT THE STRONGEST OF WARM AIR
ADVECTION SIGNALS. THE HEART OF THE SYSTEM IS OVER THE NORTHERN
GREAT LAKES...SO FORCING AND SATURATION REMAINS MINIMAL OVER THE
AREA. SO HAVE NO POPS AT THIS TIME.
NEXT WEEK THE UNCERTAINTY REALLY STARTS TO RAMP UP BY MIDWEEK AFTER
WHAT IS BECOMING A MORE FAVORED DRY SUNDAY AND MONDAY. ALTHOUGH MUCH
LIKE SATURDAY...TEMPERATURE CONFIDENCE IS FAIRLY LOW GIVEN CLOUD
POTENTIAL. IF CLOUDS ARE REMAINING INTO SUNDAY MORNING THEY VERY
WELL COULD STICK AROUND ALL THE WAY THROUGH MONDAY NIGHT AS SURFACE
PRESSURES ARE FORECAST TO BASICALLY REMAIN THE SAME...I.E. LITTLE
ADVECTION. THE LONG ADVERTISED UPPER TROUGH ACROSS THE WEST COAST
LOOKS TO EVOLVE IN THE BEGINNING OF THE WEEK AND FORCE DOWNSTREAM
RIDGING AND SOUTHWEST FLOW ALOFT. THIS TROUGH SHOULD PACK QUITE A
PUNCH OF COLD AIR INTO THE NORTHERN ROCKIES AND PLAINS...BUT THE
MAIN BAROCLINIC ZONE DURING MIDWEEK LOOKS TO REMAIN TO THE NORTHWEST
AND IF THAT IS THE CASE THEN ANY HEAVY WINTER PRECIP SHOULD AS WELL
DURING MIDWEEK...BUT AGAIN CONFIDENCE IS LOW. ENERGY THAT TRANSLATES
EAST FROM THIS TROUGH APPEARS TO BE IN PARTS AND THUS MULTIPLE
CHANCES FOR PRECIP LOOK TO BE THE CASE ACROSS THE GREAT LAKES AND
CORN BELT REGIONS DURING THE DEC 3-8 PERIOD. NIGHTTIME TEMPERATURES
SHOULD BE MORE NEAR NORMAL OR EVEN ABOVE NORMAL GIVEN CLOUD
COVER DURING MIDWEEK...BUT DAYTIME HIGHS COULD BE ANYWHERE IN A
LARGE SPECTRUM OF SOLUTIONS DEPENDING ON STRENGTH OF SOUTHERLY
FLOW AND WHEN LOW PASSAGES OCCUR. THOSE ARE BOTH VARIABLES DIFFICULT
TO LOCK DOWN IN A FORECAST PATTERN OF A BROAD TROUGH IN THE WEST.
MTF
&&
.CLIMATE...
306 AM CST
THE FORECAST HIGH TODAY FOR CHICAGO (O`HARE) IS 33 WHICH WOULD TIE
MULTIPLE THANKSGIVINGS IN THE PAST TWO DECADES FOR A COOL
HIGH...THE LAST BEING 2007. HOWEVER IF THE MERCURY STAYS BELOW
THAT...IT WOULD BE THE COLDEST HIGH TEMPERATURE ON THANKSGIVING IN
CHICAGO SINCE 1989.
SIMILARLY FOR ROCKFORD...THE 31 DEGREE FORECAST HIGH WOULD BE THE
COOLEST THANKSGIVING HIGH SINCE 1995 AND IF IT STAYS BELOW THAT IT
WOULD BE THE COOLEST SINCE 1989.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* WIND SHIFT FROM WEST SOUTHWEST TO NORTHWEST BY 20Z.
* VFR CEILINGS EXPECTED THIS AFTERNOON...WITH A CHANCE FOR A BRIEF
PERIOD OF MVFR CEILINGS EARLY THIS EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
AN APPROACHING COLD FRONT WILL PUSH ACROSS THE TERMINALS OVER THE
NEXT 1-2 HOURS WITH WEST SOUTHWEST WINDS TURNING TO THE
NORTHWEST...AND A RETURN OF VFR CEILINGS. THIS CLOUD COVER CAN BE
OBSERVED MOVING SOUTHEAST ACROSS EASTERN IOWA AND SOUTHERN
WISCONSIN...WITH DISTANCE SPEED TOOL BRINGING THIS TO RFD BY 19Z
AND TO ORD BY 20Z. SHORT TERM GUIDANCE CONTINUES TO INDICATE THE
POSSIBILITY OF MVFR CEILINGS LATER THIS EVENING...AND CANNOT RULE
THIS OUT WITH COLDER AIR MOVING ACROSS THE REGION. SO HAVE SHOWED
THIS POSSIBILITY IN THE TAF. VFR OR MVFR CEILINGS WILL NOT BE LONG
LASTING THIS EVENING...WITH THIS AREA OF CLOUD COVER EXPECTED TO
QUICKLY EXIT THE TERMINALS AND ONLY HIGH LEVEL CLOUDS TO THEN MOVE
OVER THE TERMINALS THROUGH THE REMAINDER OF THE FORECAST PERIOD.
WINDS WILL DIMINISH TONIGHT AND EVEN BECOME CALM OR LIGHT AND
VARIABLE AS HIGH PRESSURE MOVES OVERHEAD...BUT THEN INCREASE OUT
OF THE SOUTHEAST BY MID DAY FRIDAY.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
* LOW MEDIUM CONFIDENCE WITH MVFR POTENTIAL EARLY THIS EVENING.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...VFR.
SUNDAY AND MONDAY...MVFR POSSIBLE,
TUESDAY...VFR.
WEDNESDAY...CHANCE SHRA...MVFR POSSIBLE.
MDB
&&
.MARINE...
221 AM CST
THE MAIN FOCUS OF THE FORECAST CONTINUES TO BE THE POTENTIAL FOR
GALE FORCE WINDS LATE FRIDAY NIGHT THROUGH MIDDAY/EARLY AFTERNOON
SATURDAY...MAINLY ACROSS THE NORTH HALF OF THE LAKE.
CURRENTLY...SURFACE LOW PRESSURE CONTINUES TO DEEPEN AS IT MOVES
NORTHWARD INTO EASTERN QUEBEC AND NEWFOUNDLAND. HIGH PRESSURE
RIDGING IS CROSSING LAKE MICHIGAN EARLY THIS MORNING WITH A WEAK
AREA OF LOW PRESSURE OVER WESTERN MINNESOTA AND NORTHWEST IOWA.
THIS LOW WILL MOVE ACROSS NORTHERN LAKE MICHIGAN LATER TODAY AND
THIS EVENING. WINDS HAVE TURNED WEST AND SOUTHWEST THANKS TO THE
PASSAGE OF THE RIDGE AXIS WITH SPEEDS DIMINISHING BUT THEY WILL
INCREASE SOMEWHAT AS THE LOW CROSSES THE AREA LATER TODAY. A
NARROW CORRIDOR OF OFFSHORE SOUTHEASTERLY WINDS IS OCCURRING ALONG
THE MICHIGAN SHORE BUT WILL DIMINISH THROUGH MID MORNING. WINDS
ACROSS FAR NORTHERN LAKE MICHIGAN WILL BE TRICKY AS THE LOW CENTER
IS EXPECTED TO CROSS THIS AREA THIS AFTERNOON. THIS WILL LIKELY
LEAD TO AN EASTERLY SURFACE FLOW OVER FAR NORTHERN LAKE MICHIGAN
LATER THIS MORNING AND THIS AFTERNOON...WHILE THE REST OF THE LAKE
SEES WEST TO SOUTHWEST WINDS. A COOL FRONTAL BOUNDARY WILL CROSS
THE LAKE LATER TODAY TURNING WINDS TO THE NORTHWEST. HIGH PRESSURE
WILL SPREAD IN BEHIND THE FRONT AND STRENGTHEN AS IT CROSSES THE
LAKE FRIDAY BEFORE SHIFTING TO THE EAST. THIS WILL TURN WINDS BACK
TO THE SOUTH BY FRIDAY AFTERNOON WITH RATHER LIGHT SPEEDS.
THE HIGH WILL CONTINUE TO STRENGTHEN AS IT MOVES ACROSS THE NORTHEAST
U.S. WHILE A CLIPPER DROPS SOUTHEAST ACROSS WESTERN ONTARIO JUST
NORTH OF LAKE SUPERIOR SATURDAY. THE PRESSURE GRADIENT WILL TIGHTEN
BETWEEN THESE TWO SYSTEMS LEADING TO STRONG SOUTH TO SOUTHWEST WINDS
LATE FRIDAY NIGHT AND SATURDAY MORNING. THE STRONGEST SPEEDS WILL
OCCUR ACROSS NORTHERN PORTIONS OF THE LAKE. WILL HOLD WINDS TO 30 KT
FOR NOW WITH THE STRONGEST WINDS NORTH...BUT AM CONCERNED THAT AN
INCREASE TO GALES MAY BE NEEDED. THIS SYSTEM IS NOT TOO UNLIKE
SEVERAL WHICH WE SAW EARLIER THIS FALL THAT FEATURED SURFACE LOWS
PASSING TO THE NORTH AND WINDS THAT WERE HIGHER THAN EXPECTED. THIS
MAY NOT BE THE CASE WITH THIS PARTICULAR SYSTEM BUT IT IS WORTH
NOTING GIVEN THAT UNSTABLE CONDITIONS WILL BE IN PLACE ACROSS THE
LAKE SIMILAR TO THESE EARLIER SYSTEMS. A COLD FRONT CROSSES THE
LAKE SATURDAY AFTERNOON ALLOWING WINDS TO DROP OFF SATURDAY
EVENING. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE REGION
SUNDAY AND CONTINUE TO KEEP LIGHTER WINDS IN PLACE THROUGH
TUESDAY. FORECAST CONFIDENCE DROPS OFF BY WEDNESDAY BUT IT DOES
APPEAR THAT A MORE ACTIVE PATTERN WILL BE SETTING UP BRINGING
INCREASING CHANCES FOR STRONGER WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1005 AM CST THU NOV 28 2013
.DISCUSSION...
306 AM CST
THE PRIMARY FORECAST CONCERNS ARE CENTERED ON CLOUD COVER AND
TEMPERATURES THROUGH THE WEEKEND AND THEN CHANCES FOR PRECIPITATION
NEXT WEEK IN WHAT APPEARS TO POSSIBLY BE AN UNSETTLED
PATTERN...ALTHOUGH A HIGH DEGREE OF UNCERTAINTY.
ONE MORE SHORT WAVE IS DIVING SOUTHEAST ACROSS THE GREAT LAKES THIS
THANKSGIVING MORNING IN WHAT HAS BEEN A LITERAL PARADE OF THESE
COLD-AIR-REINFORCING SYSTEMS. A 1017MB SURFACE LOW REFLECTION ACROSS
IA WILL TRANSLATE EAST THIS MORNING AND WEAKEN AS IT DOES SUCH.
MORNING CLOUDS IN PLACE WERE DEVELOPED WITHIN THE WARM AIR ADVECTION
ENVELOPE OF THIS SYSTEM AND AS SUCH HAVE BASES MAINLY ABOVE 5000
FT...SO BELIEVE THEY WILL VACATE BY AFTERNOON ACROSS THE WESTERN AND
SOUTHERN FORECAST AREA GIVEN THE CLOUD-BEARING WIND FLOW. LOW-LEVEL
LAPSE RATES ARE MODESTLY STEEP BEHIND THE SYSTEM WITH SOME MARGINAL
SATURATION FORECAST AT THE TOP OF THE MIXED LAYER...SO LIKELY SOME
SCATTERED STRATOCU WILL CONTINUE. ALL-IN-ALL...EXPECTING SOME SUN
LATE THIS MORNING AND AFTERNOON. GIVEN THE 850MB AND 925MB FORECAST
TEMPS BY THE RAP AND NAM THIS AFTERNOON...WE ONCE AGAIN ARE IN THE
BOTTOM TENTH PERCENTILE FOR THIS TIME OF YEAR. THIS FAVORS HIGHS IN
THE LOWER TO MID 30S. SEE THE CLIMATE DISCUSSION BELOW FOR MORE ON
WHERE THIS STACKS UP FOR THANKSGIVING DAYS.
AS A CANADIAN SURFACE HIGH MOVES OVERHEAD TONIGHT TEMPERATURES
SHOULD RADIATE QUICKLY THIS EVE...EVEN IF IT DOES TAKE A FEW HOURS
AFTER SUNSET TO DIMINISH THE LINGERING STRATOCU. HAVE MID AND EVEN
PATCHY LOWER TEENS IN OUTLYING AREAS. AS THE WIND FIELD OVER LAKE MI
SHIFTS MORE NE TONIGHT IMMEDIATELY AHEAD OF THE HIGH CENTER...A LAKE
PLUME OF AT LEAST CLOUDS LOOKS LIKELY INTO NORTHWEST INDIANA AND
POSSIBLY NORTHEAST ILLINOIS. LAKE-INDUCED EQUILIBRIUM LEVELS AROUND
4500 FT FORECAST BY THE NAM SEEM A LITTLE SHALLOW FOR PRECIP AND ANY
PRONOUNCED CONVERGENCE IS UNLIKELY. HAVE THUS ONLY ADDED A LOW
CHANCE FOR SOME LIGHT SNOW IN NORTHWEST IN/FAR SOUTHEAST COOK COUNTY
LATE TONIGHT AS WELL AS BUMPED UP CLOUD COVER.
A MORE ZONAL PATTERN WILL MOVE OVER BY LATER FRIDAY INTO SATURDAY
BRINGING MODERATING TEMPERATURES. THERE IS A FAIR AMOUNT OF SPREAD
IN THE ENVELOPE OF GUIDANCE SOLUTIONS FOR HOW WARM SATURDAY WILL
BE...AND POTENTIAL CLOUD COVER LIKELY HAS QUITE A BIT TO DO WITH
THAT. THIS TIME OF YEAR SOUTHERLY LOW-LEVEL FLOW AFTER A COLD AIR
MASS CAN READILY BECOME "CONTAMINATED" WITH SATURATION/CLOUDS.
CLIMATOLOGY OF THE 850MB AND 925MB TEMPERATURES WOULD FAVOR MID AND
MAYBE EVEN UPPER 40S...BUT THAT WARM CURRENTLY SEEMS UNLIKELY WITH
AT LEAST SOME POTENTIAL FOR CLOUDS AND NOT THE STRONGEST OF WARM AIR
ADVECTION SIGNALS. THE HEART OF THE SYSTEM IS OVER THE NORTHERN
GREAT LAKES...SO FORCING AND SATURATION REMAINS MINIMAL OVER THE
AREA. SO HAVE NO POPS AT THIS TIME.
NEXT WEEK THE UNCERTAINTY REALLY STARTS TO RAMP UP BY MIDWEEK AFTER
WHAT IS BECOMING A MORE FAVORED DRY SUNDAY AND MONDAY. ALTHOUGH MUCH
LIKE SATURDAY...TEMPERATURE CONFIDENCE IS FAIRLY LOW GIVEN CLOUD
POTENTIAL. IF CLOUDS ARE REMAINING INTO SUNDAY MORNING THEY VERY
WELL COULD STICK AROUND ALL THE WAY THROUGH MONDAY NIGHT AS SURFACE
PRESSURES ARE FORECAST TO BASICALLY REMAIN THE SAME...I.E. LITTLE
ADVECTION. THE LONG ADVERTISED UPPER TROUGH ACROSS THE WEST COAST
LOOKS TO EVOLVE IN THE BEGINNING OF THE WEEK AND FORCE DOWNSTREAM
RIDGING AND SOUTHWEST FLOW ALOFT. THIS TROUGH SHOULD PACK QUITE A
PUNCH OF COLD AIR INTO THE NORTHERN ROCKIES AND PLAINS...BUT THE
MAIN BAROCLINIC ZONE DURING MIDWEEK LOOKS TO REMAIN TO THE NORTHWEST
AND IF THAT IS THE CASE THEN ANY HEAVY WINTER PRECIP SHOULD AS WELL
DURING MIDWEEK...BUT AGAIN CONFIDENCE IS LOW. ENERGY THAT TRANSLATES
EAST FROM THIS TROUGH APPEARS TO BE IN PARTS AND THUS MULTIPLE
CHANCES FOR PRECIP LOOK TO BE THE CASE ACROSS THE GREAT LAKES AND
CORN BELT REGIONS DURING THE DEC 3-8 PERIOD. NIGHTTIME TEMPERATURES
SHOULD BE MORE NEAR NORMAL OR EVEN ABOVE NORMAL GIVEN CLOUD
COVER DURING MIDWEEK...BUT DAYTIME HIGHS COULD BE ANYWHERE IN A
LARGE SPECTRUM OF SOLUTIONS DEPENDING ON STRENGTH OF SOUTHERLY
FLOW AND WHEN LOW PASSAGES OCCUR. THOSE ARE BOTH VARIABLES DIFFICULT
TO LOCK DOWN IN A FORECAST PATTERN OF A BROAD TROUGH IN THE WEST.
MTF
&&
.CLIMATE...
306 AM CST
THE FORECAST HIGH TODAY FOR CHICAGO (O`HARE) IS 33 WHICH WOULD TIE
MULTIPLE THANKSGIVINGS IN THE PAST TWO DECADES FOR A COOL
HIGH...THE LAST BEING 2007. HOWEVER IF THE MERCURY STAYS BELOW
THAT...IT WOULD BE THE COLDEST HIGH TEMPERATURE ON THANKSGIVING IN
CHICAGO SINCE 1989.
SIMILARLY FOR ROCKFORD...THE 31 DEGREE FORECAST HIGH WOULD BE THE
COOLEST THANKSGIVING HIGH SINCE 1995 AND IF IT STAYS BELOW THAT IT
WOULD BE THE COOLEST SINCE 1989.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* WIND SHIFT FROM SOUTHWEST TO NORTHWEST TOWARD 20Z.
* VFR EXPECTED TO CONTINUE BUT THERE IS A LOW CHANCE FOR A PERIOD
OF MVFR CIGS LATER THIS AFTERNOON.
MDB/RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE RIDGING HAS SHIFTED OFF TO THE EAST OF THE TERMINALS
ALLOWING A STEADIER SOUTHERLY FLOW TO SET UP. AN UPPER LEVEL
TROUGH IS CURRENTLY CROSSING THE AREA WITH ASSOCIATED PRECIP
REMAINING NORTHEAST OF THE AREA. VFR CLOUD SHIELD WITH BASES OF
6000-7000 FT CONTINUES TO MOVE EASTWARD WITH THE BACK EDGE OF IT
COMING INTO NORTH CENTRAL ILLINOIS. HAVE GONE AHEAD AND REDUCED
CLOUD COVER OVER THE NEXT FEW HOURS AS SATELLITE SUPPORTS THIS
CLOUD BAND EXITING TO THE EAST OF THE TERMINALS. COVERAGE COULD BE
MUCH LESS THAN THE SCT INCLUDED IN THE TAFS BUT SOME ADDITIONAL
CUMULUS COULD DEVELOP.
SOUTH TO SOUTHWEST WINDS WILL CONTINUE THROUGH THE MORNING THEN
TURN WEST AND THEN NORTHWEST WITH THE PASSAGE OF A COLD FRONTAL
BOUNDARY THIS AFTERNOON. CLOUD COVER TO THE NORTH OF THE AREA
LOOKS TO WORK SOUTHWARD INTO THE AREA LATER THIS AFTERNOON. EXPECT
THE BULK OF THIS TO BE VFR BUT SOME MVFR MAY DEVELOP FOR A BRIEF
PERIOD. WINDS WILL DIMINISH LATER THIS EVENING WHILE TRYING TO
TURN MORE NORTHERLY OVERNIGHT WITH ANY LATE DAY CLOUD COVER
EXITING THE AREA LEAVING LITTLE IN THE WAY OF SKY COVER GOING INTO
FRIDAY MORNING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* LOW CONFIDENCE IN MVFR POTENTIAL THIS AFTERNOON.
MDB/RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...VFR.
SUNDAY AND MONDAY...MVFR POSSIBLE,
TUESDAY...VFR.
WEDNESDAY...CHANCE SHRA...MVFR POSSIBLE.
MDB
&&
.MARINE...
221 AM CST
THE MAIN FOCUS OF THE FORECAST CONTINUES TO BE THE POTENTIAL FOR
GALE FORCE WINDS LATE FRIDAY NIGHT THROUGH MIDDAY/EARLY AFTERNOON
SATURDAY...MAINLY ACROSS THE NORTH HALF OF THE LAKE.
CURRENTLY...SURFACE LOW PRESSURE CONTINUES TO DEEPEN AS IT MOVES
NORTHWARD INTO EASTERN QUEBEC AND NEWFOUNDLAND. HIGH PRESSURE
RIDGING IS CROSSING LAKE MICHIGAN EARLY THIS MORNING WITH A WEAK
AREA OF LOW PRESSURE OVER WESTERN MINNESOTA AND NORTHWEST IOWA.
THIS LOW WILL MOVE ACROSS NORTHERN LAKE MICHIGAN LATER TODAY AND
THIS EVENING. WINDS HAVE TURNED WEST AND SOUTHWEST THANKS TO THE
PASSAGE OF THE RIDGE AXIS WITH SPEEDS DIMINISHING BUT THEY WILL
INCREASE SOMEWHAT AS THE LOW CROSSES THE AREA LATER TODAY. A
NARROW CORRIDOR OF OFFSHORE SOUTHEASTERLY WINDS IS OCCURRING ALONG
THE MICHIGAN SHORE BUT WILL DIMINISH THROUGH MID MORNING. WINDS
ACROSS FAR NORTHERN LAKE MICHIGAN WILL BE TRICKY AS THE LOW CENTER
IS EXPECTED TO CROSS THIS AREA THIS AFTERNOON. THIS WILL LIKELY
LEAD TO AN EASTERLY SURFACE FLOW OVER FAR NORTHERN LAKE MICHIGAN
LATER THIS MORNING AND THIS AFTERNOON...WHILE THE REST OF THE LAKE
SEES WEST TO SOUTHWEST WINDS. A COOL FRONTAL BOUNDARY WILL CROSS
THE LAKE LATER TODAY TURNING WINDS TO THE NORTHWEST. HIGH PRESSURE
WILL SPREAD IN BEHIND THE FRONT AND STRENGTHEN AS IT CROSSES THE
LAKE FRIDAY BEFORE SHIFTING TO THE EAST. THIS WILL TURN WINDS BACK
TO THE SOUTH BY FRIDAY AFTERNOON WITH RATHER LIGHT SPEEDS.
THE HIGH WILL CONTINUE TO STRENGTHEN AS IT MOVES ACROSS THE NORTHEAST
U.S. WHILE A CLIPPER DROPS SOUTHEAST ACROSS WESTERN ONTARIO JUST
NORTH OF LAKE SUPERIOR SATURDAY. THE PRESSURE GRADIENT WILL TIGHTEN
BETWEEN THESE TWO SYSTEMS LEADING TO STRONG SOUTH TO SOUTHWEST WINDS
LATE FRIDAY NIGHT AND SATURDAY MORNING. THE STRONGEST SPEEDS WILL
OCCUR ACROSS NORTHERN PORTIONS OF THE LAKE. WILL HOLD WINDS TO 30 KT
FOR NOW WITH THE STRONGEST WINDS NORTH...BUT AM CONCERNED THAT AN
INCREASE TO GALES MAY BE NEEDED. THIS SYSTEM IS NOT TOO UNLIKE
SEVERAL WHICH WE SAW EARLIER THIS FALL THAT FEATURED SURFACE LOWS
PASSING TO THE NORTH AND WINDS THAT WERE HIGHER THAN EXPECTED. THIS
MAY NOT BE THE CASE WITH THIS PARTICULAR SYSTEM BUT IT IS WORTH
NOTING GIVEN THAT UNSTABLE CONDITIONS WILL BE IN PLACE ACROSS THE
LAKE SIMILAR TO THESE EARLIER SYSTEMS. A COLD FRONT CROSSES THE
LAKE SATURDAY AFTERNOON ALLOWING WINDS TO DROP OFF SATURDAY
EVENING. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE REGION
SUNDAY AND CONTINUE TO KEEP LIGHTER WINDS IN PLACE THROUGH
TUESDAY. FORECAST CONFIDENCE DROPS OFF BY WEDNESDAY BUT IT DOES
APPEAR THAT A MORE ACTIVE PATTERN WILL BE SETTING UP BRINGING
INCREASING CHANCES FOR STRONGER WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
314 PM CST THU NOV 28 2013
.SYNOPSIS...
ISSUED AT 218 PM CST THU NOV 28 2013
A WEAK SURFACE LOW MOVED EASTWARD INTO SOUTHERN LAKE MICHIGAN
DURING THE DAY ON THURSDAY WITH A COLD FRONT STRETCHING SOUTHWESTWARD
TO KSTL TO KJLN IN SOUTHWEST MISSOURI. SURFACE HIGH SAT OVER
EASTERN NORTH DAKOTA. STRATUS ALONG THE SOUTH AND WEST SIDES OF
THE HIGH PRESSURE HAS SLOWLY DISSIPATED THROUGH THE DAY. TEMPERATURES
WERE IN THE UPPER 20S IN NORTHWEST ILLINOIS TO THE LOWER 40S IN
WEST CENTRAL ILLINOIS.
A CHANGE IN THE 500 HPA PATTERN WILL OCCUR OVER
THE NEXT SEVEN DAYS AS WE GO FROM THE CURRENT NORTHWEST FLOW ALOFT
TO A MORE ZONAL FLOW WHICH WILL CONTINUE INTO EARLY NEXT WEEK.
THIS WILL RESULT IN SLOWLY MODERATING TEMPERATURES AS THE COLD AIR
OF THE LAST WEEK RETREATS NORTHWARD.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 218 PM CST THU NOV 28 2013
MODELS ARE IN GOOD OVERALL AGREEMENT WITH THE NAM/RAP BEING AN
OUTLIER WITH LOW LEVEL MOISTURE IN PLACE ACROSS THE REGION. THE
MAIN FORECAST CONCERNS WILL BE THE POTENTIAL FOR CLOUD COVER
OVERNIGHT INTO FRIDAY AS WELL AS TEMPERATURES ON FRIDAY.
HIGH PRESSURE IS FORECAST TO BUILD SOUTHEASTWARD OVERNIGHT AND BE
CENTERED ALONG THE IOWA AND ILLINOIS BORDER BY 12 UTC ON FRIDAY. AN
EXTENSIVE STRATUS DECK DEVELOPED ON THE SOUTH AND WEST SIDES OF
THE HIGH PRESSURE THIS MORNING WITH A STRONG INVERSION IN PLACE
ACROSS THE UPPER MIDWEST AND NORTHERN PLAINS. THE 12 UTC SOUNDINGS
AT KBIS AND KABR SHOWED EXTENSIVE LOW LEVEL MOISTURE IN PLACE. THE
ECMWF...GFS... AND GEM CONTINUE TO SHOW A DRIER INVERSION IN PLACE
ACROSS THE REGION OVERNIGHT WHILE THE NAM AND RAP SHOW MORE
MOISTURE IN THE LOWER LEVELS OF THE ATMOSPHERE BUT NOT TO THE
EXTENT THAT EXISTED AT KBIS AND KABR THIS MORNING. THEREFORE I AM
NOT ANTICIPATING THE FORMATION OF NEW STRATUS TONIGHT SO GOING
WITH CLEAR SKIES TONIGHT. A GOOD RADIATIONAL COOLING NIGHT AND
EXPECT TEMPERATURES TO FALL QUICKLY THIS EVENING.
HIGH PRESSURE IS FORECAST TO SHIFT EASTWARD DURING THE DAY ON
FRIDAY WITH WINDS VEERING TO THE SOUTHEAST DURING THE AFTERNOON HOURS.
850 HPA TEMPERATURES WARM FROM -4 TO -10*C TODAY TO 0 TO -4*C ON
FRIDAY. HAVE WARMED TEMPERATURES UP BY A COUPLE OF DEGREES BUT MID
LEVEL CLOUDINESS WILL BE ON THE INCREASE TOMORROW AHEAD OF ANOTHER
WAVE THAT WILL ARRIVE ON SATURDAY. THE INCREASING CLOUDS MAY HELP
TO KEEP TEMPERATURES FROM WARMING AS THEY DID TODAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 218 PM CST THU NOV 28 2013
FRIDAY NIGHT...WEAK NORTHERN STREAM CLIPPER WILL CONTINUE MOVING TO
GREAT LAKES BY SATURDAY MORNING. OVERNIGHT LOW TEMPERATURES WILL BE
IN THE 20S.
SATURDAY AND SUNDAY...TEMPERATURES WILL RANGE NEAR OR SLIGHTLY ABOVE
NORMAL ON SATURDAY BEFORE A WEAK SURFACE TROF CROSSES THE AREA
SWITCHING THE WIND TO THE WEST NORTHWEST LATE IN THE DAY. WITH
LIMITED MOISTURE THIS TROF PASSAGE WILL BE DRY. ON SUNDAY...WEAK
COLD AIR ADVECTION BEHIND THE TROF PASSAGE WILL PRODUCE LOW
TEMPERATURES IN THE IN 20S ON SATURDAY NIGHT WITH HIGHS IN THE MID
30S ACROSS THE NORTHERN THIRD OF THE FORECAST AREA WITH HIGHS IN THE
40S OVER THE SOUTH.
MONDAY THROUGH WEDNESDAY...LATEST MEDIUM RANGE MODEL SOLUTIONS
CONTINUE TO DIVERGE BUT THERE IS OVERALL AGREEMENT IN DEVELOPING A
DEEP TROF ACROSS THE WESTERN UNITED STATES BY MID WEEK. THE ENERGETIC
SYSTEM CURRENTLY DIVING SOUTH ALONG THE WEST COAST WILL BEGIN A
PERIOD OF ACTIVE WEATHER FOR THE MIDWEST. THE 12Z GFS KEEPS THE
FORECAST AREA MAINLY DRY THROUGH TUESDAY. HOWEVER...THE 12Z ECMWF IS
FASTER AND BRINGS PRECIPITATION INTO THE REGION ON MONDAY. IN EITHER
CASE MOISTURE ADVECTION FROM THE GULF OF MEXICO AHEAD OF THE SURFACE
LOW WILL BREAK OUT PRECIPITATION EITHER MONDAY OR TUESDAY. THE
PRECIPITATION COULD FALL AS A MIXTURE OF RAIN AND SNOW.
THURSDAY AND FRIDAY...CONFIDENCE IS LOW AS MODEL SOLUTIONS SHOW
MAJOR DISCREPANCIES. THE 12Z RUN OF THE ECMWF PROGS A SURFACE
LOW TO DEVELOP OVER THE CENTRAL ROCKIES AND TRACK NORTHWEST OF IOWA
ON THURSDAY. IF THIS TRACK IS CORRECT WARM AIR ADVECTION AHEAD OF
THIS LOW WOULD PRODUCE A RAIN OR RAIN/SNOW MIX TURNING TO ALL RAIN
WITH A SNOW STORM OCCURRING OVER WESTERN IOWA AND THE NORTHERN
PLAINS. ON THE OTHER HAND THE 12Z RUN OF THE GFS TRACKS THE SURFACE
LOW FURTHER SOUTHEAST AND PROGS IT TO MOVE ACROSS MISSOURI INTO
NORTHERN ILLINOIS/INDIANA BY FRIDAY. IF THE GFS SOLUTION IS CORRECT
THERMAL PROFILES WOULD SUPPORT AN ALL SNOW EVENT LATE NEXT WEEK.
HOWEVER I MUST STRONGLY REITERATE FORECAST CONFIDENCE IS LOW.&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1136 AM CST THU NOV 28 2013
A COOL FRONT HAS SHIFTED EASTWARD INTO ILLINOIS THIS MORNING WITH
WINDS BECOMING WEST TO NORTHWEST BEHIND THE FRONT. EXPECT TAFS TO
REMAIN VFR THROUGH THE PERIOD HOWEVER MONITORING STRATUS ACROSS
THE DAKOTAS WHICH MAY MOVE INTO THE REGION AFTER 00 UTC ON FRIDAY.
IN THE MEAN TIME A CEILING OF AROUND 4KFT WILL ROTATE THROUGH KDBQ
AND KCID THIS AFTERNOON. IF THE STRATUS REMAINS IN PLACE A BKN
CEILING OF AROUND 2500 WILL MOVE INTO ALL TAF SITES. OVERNIGHT.
CONFIDENCE IS LOW THAT THIS WILL OCCUR.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...COUSINS
SHORT TERM...COUSINS
LONG TERM...KUHL
AVIATION...COUSINS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1021 AM MST THU NOV 28 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 358 AM MST THU NOV 28 2013
FORECAST PROBLEM WILL BE TEMPERATURES. SATELLITE SHOWING AN
AMPLIFIED PATTERN FROM THE PACIFIC INTO EASTERN NORTH AMERICA.
SOUTHERN PORTION OF THE TROUGH ALONG THE WEST COAST HAS SPLIT AND
CUT OFF FROM THE NORTHERN PORTION. THIS IS LEAVING A STRONG RIDGE
OVER THE WESTERN PORTION OF THE COUNTRY WITH NORTHWEST FLOW ALOFT
OVER THE AREA. DRY AIR MASS AT ALL LEVELS IS IN PLACE ACROSS THE
REGION.
MODELS DID FINE AT UPPER LEVELS. AT MID LEVELS...THE GFS WAS DOING
THE BEST WITH THE UKMET NOT TOO FAR BEHIND IT. THE NAM WAS DOING A
LITTLE BETTER THAN THE ECMWF ON THE SURFACE WIND AND PRESSURE
FIELD. NAM AND ECMWF WERE DOING A LITTLE BETTER THAN THE GFS AND
CANADIAN ON THE LOW LEVEL THERMAL FIELD.
TODAY/TONIGHT...INTERESTING AND TRICKY TEMPERATURE FORECAST. SHALLOW
COLD FRONT WAS BEGINNING TO PUSH THROUGH THE AREA AND SHOULD BE
THROUGH MOST OF THE AREA BY 12Z TODAY. COLD AIR ADVECTION WILL
CONTINUE THROUGH THE DAY AS SURFACE BECOME EASTERLY. SOME THIN HIGH
LEVEL CLOUD COVER MAY COME IN DURING THE DAY AND CONTINUE INTO
TONIGHT BUT DO NOT EXPECT IT TO BE HAMPER WARMING. WHAT MAY IMPACT
HIGH TEMPERATURES TODAY IS LARGE AREA OF STRATUS MOVING SOUTH
ACROSS NEBRASKA AT THIS TIME.
THE RAP AND NAM TENDED TO CATCH THIS BUT WERE EITHER NOT FAR ENOUGH
SOUTH OR WEST WITH THIS AREA. TAKING THOSE MODELS AT FACE VALUE
WOULD SAY THAT STRATUS AND MAYBE SOME FOG WILL MOVE INTO THE
NORTHEAST PORTION OF THE AREA THIS MORNING. THE RAP IS THE MOST
AGGRESSIVE AND KEEPS THE COLDEST TEMPERATURES THERE. AFTER
COLLABORATION...ALL I DID WAS INCREASE CLOUD COVER A LITTLE.
HOWEVER WILL CONTINUE TO MONITOR TRENDS FOR AS LONG AS POSSIBLE AND
MAKE ANY NEEDED ADJUSTMENTS. TENDED TO COOLER IN THE NORTHEAST AND
WARMER IN THE WEST AND SOUTHWEST.
FOR TONIGHT MORE THAN MODEL IS NOW CONSISTENT IN BRINGING STRATUS IN
RETURN FLOW BY LATER THIS EVENING INTO THE OVERNIGHT HOURS. THE NAM
IS THE MOST AGGRESSIVE BUT THE ECMWF...GFS AND SREF ARE NOT FAR
BEHIND. WITH THIS NEW DATA AND COLLABORATION...KEPT THE FREEZING
FOG AND INCREASED THE SKY COVER AFTER 06Z. DEPENDING ON HOW FAST THE
STRATUS COMES IN...EASTERN LOCATIONS COULD DROP QUICKLY.
FRIDAY/FRIDAY NIGHT...STRATUS LOOKS TO HANG ON THROUGH THE MORNING
WHICH COULD IMPACT TEMPERATURES...ESPECIALLY IF IT HANGS ON LONGER.
MODELS STILL WAFFLING BACK AND FORTH AS TO HOW FAR BACK EAST TO TAKE
THE COLD AIR/COLD FRONT. EARLIER OUTPUT TENDED TO KEEP THE COLD AIR
FARTHER WEST WHILE THE NEWER OUTPUT IS NOW FURTHER EAST. ONE THING
FOR SURE...WILL DEFINITELY HAVE QUITE A GRADIENT IN TEMPERATURES
WITH A HIGH DEGREE OF UNCERTAINTY/POTENTIAL TO BE VERY WRONG.
SATURDAY/SATURDAY NIGHT...MODELS THEN START HAVING PROBLEMS IN
RESOLVING THE MID AND UPPER LEVEL FLOW WITH LITTLE AGREEMENT SHOWN BY
THE OUTPUT. WEST NORTHWEST TO NORTHWEST FLOW ALOFT WITH EMBEDDED
SHORTWAVES COME THROUGH DURING THIS TIME. THE STRONGEST ONE MOVES
ACROSS THE NORTH CENTRAL PORTION OF THE COUNTRY. THIS PUSHES
ANOTHER COLD FRONT THROUGH FROM LATE IN THE MORNING INTO THE EARLY
AFTERNOON. THE BRUNT OF THE COOLING LOOKS TO OCCUR OVER THE EASTERN
THIRD TO HALF. SO ONCE AGAIN THERE COULD BE A BIG GRADIENT IN
TEMPERATURES ACROSS THE AREA. CURRENT GRIDS HAD THIS LAYOUT
CAPTURED WELL AND ONLY MADE SLIGHT ADJUSTMENTS. BUT THERE IS
POTENTIAL THAT THESE TEMPERATURES WILL NEED TO BE ADJUSTED IF THE
SPEED AND POSITION OF THIS FRONT CHANGES.
THANKS TO ALL FOR THE COLLABORATION.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM MST THU NOV 28 2013
H5 ZONAL FLOW AND H3 CONFLUENCE WILL BE IN PLACE THROUGH THE EARLY
PART OF THE WEEK...WHICH WILL SUPPORT LARGE SCALE STABLE/DRY
CONDITIONS OVER MUCH OF THE PLAINS. SURFACE TO H85 W-SW FLOW
ASSOCIATED WITH LEE TROUGH DEVELOPMENT ALONG THE KS/CO BORDER WILL
SUPPORT WAA AND MILD TEMPERATURES ACROSS THE REGION. A WEAK COLD
FRONT OVER THE NORTHERN PLAINS WILL LIFT NORTH AND EAST SUNDAY WITH
HIGHS WARMING TO LOW TO MID 50S. CONTINUED MODERATION OF AIR MASS ON
MONDAY SHOULD SUPPORT HIGHS AT LEAST IN THE MID 50S. ECMWF MOS
CONTINUES TO SHOW HIGHS IN UPPER 50S/NEAR 60F AND BASED ON WARM
EPISODES IN THE SHORT TERM THIS MIGHT BE REASONABLE.
TUESDAY-WEDNESDAY NIGHT...LESS CONFIDENCE IN THESE PERIODS REGARDING
FINER DETAILS OF TEMPS/PRECIP CHANCES...HOWEVER GUIDANCE CONTINUES
TO ADVERTISE A LARGE SCALE SHIFT IN THE PATTERN ACROSS THE WESTERN
US. A STRONG UPPER LOW ORIGINATING OVER ALASKA IS ADVERTISED TO DROP
SOUTH ALONG AMPLIFIED PACIFIC RIDGE INTO THE PACIFIC NW BY MONDAY
NIGHT PULLING WITH IT A STRONG ARCTIC AIR MASS FROM POLAR REGIONS
INTO THE NORTHERN PLAINS. GEM IS THE FASTEST ON ARCTIC FRONT MOVING
INTO OUR CWA TUESDAY EVENING...HOWEVER LAST FEW RUNS OF
ECMWF/GFS/GEFS LEAN TOWARDS A SLOWER FRONTAL TIMING (POSSIBLY AS
LATE AS WED NIGHT). THERE IS A LARGE AMOUNT OF SPREAD REGARDING THE
EVOLUTION OF THE UPPER LOW IN THE WESTERN US...WHICH WILL IMPACT
ONSET OF PRECIPITATION AND THE MAGNITUDE OF COLD AIR. YESTERDAYS 12Z
RUN OF ECMWF WAS AN EXTREME (AND CONCERNING) OUTLIER WITH H85 TEMPS
BY NEXT THU -20C OR COLDER OVER PARTS OF OUR CWA. LATEST RUN OF
ECMWF AND GFS ARE A LITTLE MORE IN LINE...HOWEVER BOTH WOULD SUPPORT
VERY COLD TEMPERATURES SETTLING IN BY AT LEAST THE LATER PART OF
NEXT WEEK. CONSIDERING THE PATTERN SHOULD SUPPORT AT LEAST BREEZY
CONDITIONS AND VERY COLD OVERNIGHT TEMPS WE MAY END UP SEEING THE
NEED FOR A WIND CHILL ADVISORY (WC VALUES LESS/EQUAL TO -15F) OR
WARNING IF THE EXTREME SPECTRUM OF GUIDANCE WERE TO VERIFY. I TEND
TO LEAN TOWARD THE MODEL MEAN AT THIS POINT FOR TUE/WED CONSIDERING
RUN-RUN DIFFERENCES WHICH SHOWS COLDER TEMPS AND BETTER PRECIP
CHANCES DELAYED TOWARDS WED/WED NIGHT AND OUTSIDE OUR CURRENT VALID
FORECAST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1014 AM MST THU NOV 28 2013
AT KMCK...STRATUS DECK HAS BEEN STEADILY ADVANCING TOWARDS THE
TERMINAL ALL MORNING AND A PERIOD OF LOWER CIGS IS EXPECTED
ROUGHLY BETWEEN 19Z AND 22Z THIS AFTERNOON. SATELLITE TRENDS SHOW
SOME EROSION ON THE LEADING EDGE...SO THERE IS STILL SOME
UNCERTAINTY THAT THE STRATUS CAN BE MAINTAINED WITH SURFACE
HEATING. TONIGHT...LOW CIGS WITH THE STRATUS WILL STILL BE A
POSSIBILITY ALTHOUGH THE WINDS ARE LIGHT THEY WILL HAVE AN UPSLOPE
COMPONENT. PATCHY FREEZING FOG MAY ALSO DEVELOP IN THE OVERNIGHT
BUT CONFIDENCE IS LACKING TO MENTION ATTM.
AT KGLD...VFR EXPECTED THROUGH THE AFTERNOON AND EARLY EVENING.
HOWEVER AS THE NIGHT WEARS ON LIGHT UPSLOPE WINDS WILL CONTRIBUTE
TO THE DEVELOPMENT OF STRATUS AND POSSIBLE LOW CIGS. PATCHY FREEZING
FOG MAY ALSO DEVELOP IN THE OVERNIGHT BUT CONFIDENCE IS LACKING
TO MENTION ATTM.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...DJR
AVIATION...024
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1248 PM EST THU NOV 28 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 343 AM EST THU NOV 28 2013
A CLIPPER SYSTEM WILL BRING LAKE ENHANCED SNOWFALL TO THE REGION
TODAY. TWO TO FIVE INCHES CAN BE EXPECTED BY THIS EVENING NORTH OF
I-96...WHILE AREAS SOUTH OF I-96 WILL ONLY GET TWO INCHES OR LESS.
THE SNOW IS EXPECTED TO GRADUALLY TAPER OFF TONIGHT. AFTER A QUIET
FRIDAY AND FRIDAY NIGHT...ANOTHER COLD FRONT COMES IN FOR
SATURDAY. THIS SYSTEM LOOKS TO BE WEAKER AND SHOULD ONLY GIVE THE
REGION A DUSTING OF SNOW.
THE WEEKEND AND INTO EARLY NEXT WEEK LOOKS QUIET...WITH THE NEXT
CHANCE OF PRECIPITATION COMING IN ON WEDNESDAY. HIGH TEMPERATURES
SHOULD MAINLY BE IN THE 30S.
&&
.UPDATE...
ISSUED AT 1150 PM EST THU NOV 28 2013
THE ADVISORIES HAVE BEEN UPDATED..MAIN EXPECTATION IS AREA OF
LOCALIZED 3 TO 6 INCH SNOW POTENTIAL WITH NICE AREA OF SNOW
THAT HAS DEVELOPED WEST AND NORTH OF GRAND RAPIDS AND INLAND FROM
HOLLAND...MUSKEOGON...WHITEHALL. THE HRRR HAS THE BEST HANDLE ON
THIS AREA ALTHOUGH IT DEVELOPED ABOUT 2 HOURS AHEAD OF WHAT THE
HRRR WAS INDICATING EARLIER. THIS AREA WILL PERSIST THROUGH THE
EARLY AFTNERNOON BEFORE GRADUALLY PIVOTING EAST AND SOUTH AND
WEAKENING. SO GRAND RAPIDS MAY SEE ANOTHER PERIOD OF LIGHT SNOW
LATE AFTERNOON INTO EARLY THIS EVENING...OTHERWISE THE EVENT IS
ABOUT OVER.
THE ENHANCED SNOW IS ASSOCIATED WITH AN AREA OF COVERGING LAKE
MOISTURE INTO A WEAK TROUGH OF LOW PRESSURE EXTENDING ACROSS THE
STATE. LOW LEVEL CLOUD TEMPERATURES ARE GREAT TODAY FOR BOTH THE
EFFICIENT PRODUCTION OF PRECIPITATON AND HIGH SNOW TO LIQUID
RATIOS...I.E. LARGE...DRY...AND FLUFFY SNOWFLAKES. BASED ON PAST
SIMILAR SCENARIOS...WOULD NOT BE SURPRISED TO SEE VERY LOCAL
ADDITIONAL SNOWFALL OF 6+ INCHES THIS AFTERNOON...BUT THE LIGHT
NATURE OF THE SNOW WILL MITIGATE THE POTENTIAL IMPACTS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 343 AM EST THU NOV 28 2013
WILL KEEP THE SAME COUNTIES IN THE HEADLINE...BUT NOW THAT WE A
TRANSITIONING INTO A SYNOPTIC/LAKE EFFECT COMBO EVENT...WILL JUST
CALL IT A WINTER WEATHER ADVISORY FOR ALL COUNTIES.
SOLID SW FLOW ENHANCED EVENT EVOLVING EARLY THIS MORNING. THE N/S
ORIENTED LAKE BAND FROM OVERNIGHT WAS BEING PUSHED INLAND AS THE
FLOW WAS GOING WEST AND WILL CONTINUE TO BACK TO THE SW LATE THIS
MORNING. DEEP MOISTURE SEEN WITHIN THE DGZ ALONG WITH A STRONG
OMEGA FOR THE CLASSIC BULLS-EYE WHICH SHOULD RESULT IN LARGER FLAKES
AND FAVORABLE ACCUMULATION RATES BY LATE MORNING/EARLY AFTERNOON.
INCREASED SNOW TOTALS FOR PORTIONS OF THE NW CWA AS THIS AREA SHOULD
SEE THE BEST SYNOPTIC/LE COMBO. FEEL WE WILL SEE A FEW 5-6 INCH
REPORTS FROM THIS ONE. THE HIGHEST TOTALS SHOULD OCCUR WHERE
OROGRAPHIC LIFT ALSO PITCHES IN...OVER NORTHERN NEWAYGO AND LAKE
COUNTIES.
AS THE WAVE PASSES EAST THE FLOW WILL PIVOT TO THE WNW TOWARD
NIGHTFALL...THEN CONTINUE TO PIVOT TO THE NNW BY LATE EVENING. THIS
WILL SPRAY MUCH OF THE WESTERN HALF WITH SNOWFALL THIS EVENING.
THEN INVERSION HEIGHTS CRASH TOWARD MIDNIGHT WHEN THE SNOW WILL
DIMINISH.
ANOTHER NORTHERN STREAM SYSTEM MOVES IN FOR SATURDAY. THIS APPEARS
TO BE A WEAKER SYSTEM THAT SHOULD ONLY PUT DOWN MINIMAL SNOWS...LESS
THAN AN INCH...AND MAINLY NORTH OF I-96. H8 TEMPS WARM BY THEN...SO
IT APPEARS THIS SYSTEM WILL NOT HAVE MUCH LAKE EFFECT POTENTIAL.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 343 AM EST THU NOV 28 2013
THE LONG TERM PERIOD WILL BE PREDOMINATELY DRY WITH TEMPERATURES
CLOSE TO NORMAL. SFC HIGH PRESSURE TO OUR NORTH OVER ONTARIO WILL
PROVIDE MICHIGAN WITH A DRY/COOL EASTERLY FLOW OF AIR AND A
PREDOMINATELY FLAT/ZONAL FLOW ALOFT WILL RESULT IN A VERY LOW
POTENTIAL FOR ANY SIGNIFICANT SYSTEMS.
THE UPPER FLOW DOES BEGIN TO AMPLIFY FOR THE MIDDLE TO LATE PART OF
NEXT WEEK WITH A LONG WAVE TROUGH DEVELOPING OVER THE WRN UNITED
STATES. SO THE PATTERN SHOULD BECOME MORE ACTIVE FOR SW MI BY NEXT
THURSDAY... BUT CURRENTLY IT LOOKS LIKE RAIN WOULD BE THE MAIN
PRECIP TYPE.
THE COLD FRONT WHICH PASSES THROUGH ON SATURDAY NIGHT BRINGS DOWN H8
AIR NEAR -10C. THIS SHOULD BE COLD ENOUGH TO GENERATE SOME LAKE
EFFECT CLOUDINESS AND LIGHT SNOW SHOWERS OR FLURRIES. INITIALLY ON
SUNDAY THE FLOW IS NORTHERLY WHICH SUPPORTS SOME LIGHT SNOW ACROSS
PORTIONS OF MASON AND OCEANA COUNTIES. THEN FOR SUNDAY NIGHT THROUGH
TUESDAY THE LOW LEVEL FLOW IS MORE EASTERLY WHICH MEANS MOST OF THE
AREA WILL BE DRY ALTHOUGH SOME FLURRIES FROM LAKE HURON MAY MAKE IT
INLAND TOWARD THE CLARE AREA.
THE DRY LOW LEVEL EAST FLOW AND SURFACE RIDGING MAY DELAY/FEND OFF
INCOMING WAA PRECIP NEXT WEDNESDAY BUT MAY ALSO RESULT IN A WINTRY
MIX AT THE PRECIP ONSET WED NIGHT DUE TO EVAPORATIVE COOLING/WET
BULB EFFECTS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1239 PM EST THU NOV 28 2013
LIGHT SNOW WILL DIMINISH THIS EVENING. CIGS SHOULD REMAIN MOSTLY
VFR EXCEPT AT KMKG THIS AFTERNOON.
&&
.MARINE...
ISSUED AT 343 AM EST THU NOV 28 2013
EXTENDED THE SCA THROUGH TODAY AS THE SW FLOW REMAIN BRISK. AFTER A
CALMER PERIOD FOR TONIGHT AND FRIDAY...WE MAY NEED ANOTHER SCA BY
FRIDAY NIGHT AS SSW WINDS INCREASE.
&&
.HYDROLOGY...
ISSUED AT 343 AM EST THU NOV 28 2013
PCPN WILL BE ALL SNOW THROUGH THE SHORT TERM WITH MINIMAL MELTING...
SO NO HYDRO IMPACTS ARE EXPECTED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
MIZ037>040-043>046-050-051-056-057-064.
FLOOD WATCH THROUGH SATURDAY EVENING FOR MIZ045.
LM...NONE.
&&
$$
UPDATE...COBB
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...MEADE
AVIATION...93
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1238 PM EST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EST THU NOV 28 2013
LARGE SCALE FIRST...THEN LETS TALK ABOUT MESOSCALE AND LK EFFECT
ISSUES THAT ARE PLENTY. SHORTWAVE AND LOW PRESSURE TROUGH IN COOL NW
FLOW CLOSING IN ON WESTERN UPR MICHIGAN. BATCH OF LGT SNOW EXTENDS
FROM FAR WEST CWA TO THE NORTHWEST ALONG MN/ONTARIO BORDER. SO
WIDESPREAD LGT SNOW WILL IMPACT THOSE TRAVELING THIS THANKSGIVING
MORNING...ESPECIALLY OVER WESTERN CWA AND TOWARD WISCONSIN BORDER
WHERE BETTER FORCING WITH THE SHORTWAVE RESIDES. OMEGA IN THE H7-H6
LAYER EXITS AFT 15Z...LEAVING MOSTLY NEGATIVE LARGE SCALE FORCING
THROUGH TONIGHT.
NOW ONTO THE MESOSCALE AND LAKE EFFECT ISSUES. IT IS NEVER A GOOD
THING WHEN A LARGER SCALE TROUGH MERGES INTO AN UNSTABLE AND LIGHT
WIND LAKE EFFECT ENVIRONMENT. CRAZY THINGS CAN HAPPEN. TODAY MAY END
UP BEING ONE OF THESE DAYS. ONLY TIME WILL TELL. LK EFFECT IS ALREADY
ONGOING. FIRST FOR LK SUPERIOR...STRONG MESOLOW CIRCULATION IS TAKING
OFF JUST OFFSHORE OF MUNSING AND MAY ACTUALLY BE CLIPPING GRAND
ISLAND. THIS IS LIKELY THE BEGINNING OF EVENTUAL HEAVY SNOW BAND TO
IMPACT FAR NORTHERN KEWEENAW PENINSULA...VCNTY OF DELAWARE AND COPPER
HARBOR...THOUGH MIDDAY. WINDS OVER LK SUPERIOR ARE MAINLY NE AT THIS
TIME...BUT TOWARD THE SOUTH SHORE ARE BECOMING VARIABLE OR EVEN SOUTH
THANKS TO APPROACHING LOW PRESSURE TROUGH AND LAND BREEZES /ACTUALLY
SAW TEMPS DIP BLO ZERO OVR PARTS OF INTERIOR EASTERN UPR MICHIGAN
THIS MORNING SHOWING THE CHILL OF THE AIRMASS/. AS THE MORNING WEARS
ON...INCREASING SOUTH WINDS WILL CONVERGE WITH ENE WINDS OVR LK
SUPERIOR RESULTING IN DOMINANT BAND OF SNOW OVR TIP OF KEWEENAW.
ALREADY SEEING ECHOES ON MQT RADAR NEAR COPPER HARBOR BUT NOTHING YET
PER THE KEWEENAW CO SHERIFF IN EAGLE RIVER. 00Z NAM SEEMED TOO QUICK
IN SWINGING DOMINANT BAND BACK TO SOUTH THIS AFTN. 06Z NAM ADJUSTED
AND NOW LOOKS LIKE PREFERRED 00Z GEM-REGIONAL AND LOCAL WRF-ARW AND
RUC13. UPSHOT IS HEAVIER SNOW HANGS OUT ON TIP OF KEWEENAW THROUGH
MIDDAY THEN SINKS SOUTH WITH MORE BRIEF HEAVIER SNOW SOUTH OF CALUMET
BY MID-LATE AFTN. OVERALL THE GOING LK EFFECT SNOW ADVY LOOKS
GOOD...THOUGH ISOLD AMOUNTS UP TO 10 INCHES NOT OUT QUESTION IF BAND
STAYS IN SAME LOCATION.
NOT ALL ABOUT LK SUPERIOR THOUGH AS LK MICHIGAN COULD BE INTERESTING
AS WELL. SOUTH WINDS FORMING ON LK MICHIGAN ARE LEADING TO CONCERNS
THAT LK EFFECT...POSSIBLY HEAVY...COULD IMPACT PARTS OF DELTA AND
SOUTHERN SCHOOLCRAFT INTO THIS AFTN. GRB/APX RADAR ALREADY SHOWING
SIGNS OF LK EFFECT MESO FEATURES ALONG DOOR PENINSULA AND ALONG NW
SHORE OF NORTHERN LOWER MICHIGAN. RUC13 SFC CONVERGENCE FIELD DOING
VERY NICE JOB OF PEGGING THESE AREAS AND IT SHOWS THEM MERGING OVER
FAR NORTHERN LK MICHIGAN AFT 15Z AND AFFECTING MAINLY GARDEN
PENINSULA ACROSS SOUTHERN SCHOOLCRAFT ZONE THIS AFTN. WAS VERY CLOSE
TO GO WITH ADVY...BUT CONFIDENCE WAS NOT THERE AS THESE IS UNCERTAINTY
IN HOW FAR NORTH THESE CIRCULATIONS WILL GET. RUC FCST IS VERIFYING
WELL THOUGH AND DOES GET A LOT OF MERIT. SO...WILL PASS THIS ON TO
DAYSHIFT AND LET THEM SEE HOW THINGS LOOK AFT DAYBREAK. PUT OUT A
STRONGLY WORDED SPS AND MENTIONED THAT EITHER ADVY/WARNING COULD BE
NEEDED LATER TODAY. ANYTHING IS POSSIBLE IN THIS KIND OF SETUP.
TONIGHT WILL BASICALLY BE AN EXTENSION OF HOW LK EFFECT DEVELOPS
TODAY...SO IT IS STILL KIND OF UNCERTAIN. LEANED ON NCEP HIGH RES
WRF-ARW AND NMM RUNS AS WELL AS NAM WHICH COMES BACK INTO LINE WITH
GOING THINKING. GENERALLY...SFC TROUGH SHOULD MOVE TO EASTERN LK
SUPERIOR ALLOWING WINDS TO BECOME MORE NW OR WEST OVR MUCH OF UPR
MICHIGAN. FIRST IMPACT WILL BE TO SHUNT LK EFFECT OFF LK MICHIGAN
BACK TO THE SOUTH. HAVE CHANCES VERY EARLY IN THE EVENING...THEN
DROP THEM TO SLIGHTS BY LATE EVENING. FARTHER NORTH...LK EFFECT SNOW
SHOWERS WILL BE AFFECTING NORTHWEST CWA LATE AFTN/EARLY EVENING AND
SHOULD SINK TOWARD NCNTRL UPR MICHIGAN...BIG BAY/MARQUETTE THROUGH
THE EVENING AND OVERNIGHT HOURS AND EVENTUALLY MAKE IT ONSHORE TO
EAST OF MARQUETTE TOWARD MUNISING AND GRAND MARAIS LATER TONIGHT.
MODERATE ACCUMS COULD OCCUR TONIGHT FOR HIGHER TERRAIN OF
WEST...VCNTY OF PORCUPINE MTS AND SETUP SEEMS GOOD FOR CONVERGENT
BAND OF SNOW TO AFFECT GOOD PART OF BARAGA COUNTY...MAYBE EVEN RIGHT
ALONG LK SHORE AT BARAGA/L`ANSE AS WELL. FOR NOW HAVE 2-4 INCHES IN
THERE FOR THESE AREAS THIS EVENING. LOCALLY HEAVY SNOW MAY SPREAD TO
BIG BAY/MARQUETTE LATER TONIGHT AS CONVERGENCE MAXIMIZES BTWN NW WINDS
OVER LK SUPERIOR AND POSSIBLE LAND BREEZE OVER CNTRL UPR MICHIGAN.
INLAND FM ALL THE LK EFFECT AND CLOUDS...SOME CLEARING AND LIGHTER
WINDS MAY ALLOW TEMPS TO FALL INTO THE SINGLE DIGITS TOWARD WI
BORDER AND OVER INTERIOR EASTERN CWA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 505 AM EST THU NOV 28 2013
FRIDAY...A SPRAWLING SFC HIGH FROM NRN ONTARIO INTO THE OHIO VALLEY
WILL RESULT IN A VERY WEAK GRADIENT ACROSS THE NRN GREAT LAKES. THE
HIGH RES MODELS SUGGEST THAT THE CIRCULATION AROUND A LAKE INDUCED
LOW OR TROUGH OVER SE LAKE SUPERIOR COULD FOCUS LES BANDS ANYWHERE FROM
MARQUETTE TO MUNISING. IF THE LOW LEVEL CONVERGENCE IS STRONG ENOUGH
THERE MAY BE A PERIOD OF HEAVY SNOW. HOWEVER...CONFIDENCE IN THE
LOCATION AND DURATION OF SUCH A BAND IS LOW. SO...FCST SNOWFALL
AMOUNTS WERE LIMITED TO AROUND AN INCH. DEVELOPING SRLY FLOW IN THE
AFTERNOON WILL PUSH THE REMAINING LES OFFSHORE. ANY SNOWBANDS MOVING
INTO THE WEST SHOULD ALSO WEAKEN AND POSSIBLY LINGER ALONG THE
SHORELINE UNTIL AFTERNOON WHEN OFF SHORE WINDS STRENGTHEN. 850 MB WAA
WILL INCREASE IN THE AFTERNOON AS WEAK MID LEVEL RIDGING MOVES BACK
OVER THE AREA AND A SFC HIGH BUILDS INTO THE ERN LAKES. HIGH TEMPS
ARE EXPECTED TO REBOUND INTO THE MID AND UPPER 20S.
FRI NIGHT AND SAT...THE MODELS WERE IN GOOD AGREEMENT WITH THE NEXT
CLIPPER SHORTWAVE TROUGH SLIDING ACROSS NRN LAKE SUPERIOR LATE IN THE
DAY ON SATURDAY. LIGHT SNOW DEVELOPING OVER SCNTRL CANADA IN THE WAA
PATTERN AHEAD OF THE SHORTWAVE WILL SPREAD SNOW ACROSS NRN LAKE
SUPERIOR FRI NIGHT PERHAPS BRUSHING THE NRN AND ERN COUNTIES WITH
SOME LIGHT SNOW LATE FRI NIGHT INTO SAT. THE STRONGER FORCING AND
BETTER SNOW POTENTIAL IS EXPECTED TO REMAIN NORTH OF LAKE SUPERIOR.
HOWEVER...THERE MAY ALSO BE A PERIOD OF LAKE ENAHCNED SNOW INTO THE
ERN CWA FROM LATE FRI NIGHT INTO SAT WITH SSW LOW LEVEL FLOW OFF OF LAKE
MI VEERING TO THE SW. THE LONG FETCH WILL BE FAVORABLE BUT
INSTABILITY WILL BE LIMITED WITH RELATIVELY DRY AIR OVER THE AREA
BEFORE THE SHRTWV ARRIVES AND WAA PUSHING 850 MB TEMPS -8C TO -5C.
SAT NIGHT...SOME LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE
WAKE OF THE SFC TROUGH AS WINDS VEER FROM NW TO N AND 850 MB TEMPS
DROP FROM -10C TO -12C. WITH ONLY MARGINAL INSTABILITY...ONLY CHANCE
POPS WERE INCLUDED.
SUN INTO MON...AS HIGH PRES BUILDS INTO NRN ONTARIO WINDS WILL
CONTINUE TO VEER FROM NNE TO E. 850 MB TEMPS AROUND -12C WILL
PROVIDE JUST ENOUGH INSTABILITY TO KEEP LES CHANCES GOING ACROSS
NORTH CENTRAL UPPER MICHIGAN AND THE KEWEENAW. NEAR NORMAL TEMPS ARE
EXPECTED WITH HIGHS AROUND 30 TO THE LOWER 30S AND LOWS IN THE LOWER
20S.
TUE AND WED...MODELS DIFFER WITH THE APPROACH OF THE NEXT
SHORTWAVE EMERGING FROM THE WRN CONUS TROF. THE GFS INDICATES A MORE
POSITIVE-TILT WRN CONUS TROF AND LESS AMPLIFICATION OF RIDGE
DOWNSTREAM ALLOWING FOR A QUICKER ADVANCE OF A SHORTWAVE AND ASSOCIATED
FRONTAL SYSTEM INTO THE WRN LAKES. THE ECMWF INDICATES A MORE
AMPLIFIED PATTERN ACROSS THE CONUS WITH A SLOWER ADVANCE OF THE
SHORTWAVE MOVING TOWARD THE WRN LAKES. THE FCST CONTINUED TO USE A
MDLS CONSENSUS THAT REFLECTS A SLIGHTLY LATER ARRIVAL OF PCPN
CHANCES FROM TUE NIGHT INTO WED. THE MODELS ALSO TRENDED TOWARD A
LESS AMPLIFIED SOLUTION WITH COLDER AIR ACROSS THE NRN LAKES WHICH
WOULD REDUCE THE CHANCE FOR ANY RAIN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1237 PM EST THU NOV 28 2013
FORECAST WILL BE A CHALLENGE OVER THE NEXT 24HRS. MULTIPLE MESO-LOWS
OVER LAKE SUPERIOR THAT ARE NOT HANDLED WELL BY ANY MODELS SHOULD
MOVE ONSHORE TODAY INTO TONIGHT...MAKING ALL TAF ELEMENTS VERY
DIFFICULT TO FORECAST MORE THAN A COUPLE HOURS OUT. PUT BEST GUESS
INTO TAFS...BUT MULTIPLE AMENDMENTS MAY BE NEEDED AS VERY SMALL
SCALE FEATURES MOVE OVER TAF SITES. SEEMS CMX HAS THE BEST CHANCE OF
SEEING LOWERED CONDITIONS AS A HEAVY LAKE EFFECT SNOW BAND OVER THE
NORTHERN KEWEENAW MOVES SOUTH. IWD HAS THE NEXT BEST CHANCE OF
LOWERING CONDITIONS AS A STRONG MESO-LOW OVER WESTERN LAKE SUPERIOR
MOVES ONSHORE IN NW WI OR WRN UPPER MI. SAW HAS THE LOWEST CHANCES
OF SEEING DECREASED CONDITIONS...BUT THERE IS STILL A CHANCE THAT A
MESO-LOW OVER SOUTH CENTRAL LAKE SUPERIOR WILL MOVE ONSHORE NEAR
MARQUETTE THAT WOULD IMPACT THAT SITE AS WELL.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 343 PM EST WED NOV 27 2013
STRONGER N WINDS WILL CONTINUE TO SLOWLY DIMINISH THIS EVENING. A
RIDGE OF HIGH PRESSURE WILL EXTEND OVER LAKE SUPERIOR THIS
EVENING...WHILE A WEAK LOW OVER THE EASTERN DAKOTAS PUSHES ACROSS
THE UPPER GREAT LAKES LATE TONIGHT THROUGH THURSDAY. LARGER HIGH
PRESSURE EXTENDING ACROSS MUCH OF CENTRAL CANADA THROUGH THE CENTRAL
PLAINS THURSDAY AFTERNOON WILL SWING ACROSS THE UPPER GREAT LAKES
THURSDAY NIGHT...BEFORE EXITING TO THE LOWER GREAT LAKES AND NEW
ENGLAND STATES FRIDAY AFTERNOON THROUGH SATURDAY. EXPECT A LOW OVER
LAKE WINNIPEG FRIDAY NIGHT TO PUSH ACROSS SOUTHERN ONTARIO AND LAKE
SUPERIOR SATURDAY AND SATURDAY EVENING. THERE IS THE POTENTIAL FOR
30KT S GUSTS DURING THE DAY SATURDAY. FOR SUNDAY AND MONDAY...HIGH
PRESSURE SCOOTING ACROSS ONTARIO WILL PUSH A RIDGE OVER LAKE
SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
MIZ001.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...JLB
AVIATION...TITUS
MARINE...KF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1154 AM EST THU NOV 28 2013
LATEST UPDATE...MORNING UPDATE
.SYNOPSIS...
ISSUED AT 343 AM EST THU NOV 28 2013
A CLIPPER SYSTEM WILL BRING LAKE ENHANCED SNOWFALL TO THE REGION
TODAY. TWO TO FIVE INCHES CAN BE EXPECTED BY THIS EVENING NORTH OF
I-96...WHILE AREAS SOUTH OF I-96 WILL ONLY GET TWO INCHES OR LESS.
THE SNOW IS EXPECTED TO GRADUALLY TAPER OFF TONIGHT. AFTER A QUIET
FRIDAY AND FRIDAY NIGHT...ANOTHER COLD FRONT COMES IN FOR
SATURDAY. THIS SYSTEM LOOKS TO BE WEAKER AND SHOULD ONLY GIVE THE
REGION A DUSTING OF SNOW.
THE WEEKEND AND INTO EARLY NEXT WEEK LOOKS QUIET...WITH THE NEXT
CHANCE OF PRECIPITATION COMING IN ON WEDNESDAY. HIGH TEMPERATURES
SHOULD MAINLY BE IN THE 30S.
&&
.UPDATE...
ISSUED AT 1150 PM EST THU NOV 28 2013
THE ADVISORIES HAVE BEEN UPDATED..MAIN EXPECTATION IS AREA OF
LOCALIZED 3 TO 6 INCH SNOW POTENTIAL WITH NICE AREA OF SNOW
THAT HAS DEVELOPED WEST AND NORTH OF GRAND RAPIDS AND INLAND FROM
HOLLAND...MUSKEOGON...WHITEHALL. THE HRRR HAS THE BEST HANDLE ON
THIS AREA ALTHOUGH IT DEVELOPED ABOUT 2 HOURS AHEAD OF WHAT THE
HRRR WAS INDICATING EARLIER. THIS AREA WILL PERSIST THROUGH THE
EARLY AFTNERNOON BEFORE GRADUALLY PIVOTING EAST AND SOUTH AND
WEAKENING. SO GRAND RAPIDS MAY SEE ANOTHER PERIOD OF LIGHT SNOW
LATE AFTERNOON INTO EARLY THIS EVENING...OTHERWISE THE EVENT IS
ABOUT OVER.
THE ENHANCED SNOW IS ASSOCIATED WITH AN AREA OF COVERGING LAKE
MOISTURE INTO A WEAK TROUGH OF LOW PRESSURE EXTENDING ACROSS THE
STATE. LOW LEVEL CLOUD TEMPERATURES ARE GREAT TODAY FOR BOTH THE
EFFICIENT PRODUCTION OF PRECIPITATON AND HIGH SNOW TO LIQUID
RATIOS...I.E. LARGE...DRY...AND FLUFFY SNOWFLAKES. BASED ON PAST
SIMILAR SCENARIOS...WOULD NOT BE SURPRISED TO SEE VERY LOCAL
ADDITIONAL SNOWFALL OF 6+ INCHES THIS AFTERNOON...BUT THE LIGHT
NATURE OF THE SNOW WILL MITIGATE THE POTENTIAL IMPACTS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 343 AM EST THU NOV 28 2013
WILL KEEP THE SAME COUNTIES IN THE HEADLINE...BUT NOW THAT WE A
TRANSITIONING INTO A SYNOPTIC/LAKE EFFECT COMBO EVENT...WILL JUST
CALL IT A WINTER WEATHER ADVISORY FOR ALL COUNTIES.
SOLID SW FLOW ENHANCED EVENT EVOLVING EARLY THIS MORNING. THE N/S
ORIENTED LAKE BAND FROM OVERNIGHT WAS BEING PUSHED INLAND AS THE
FLOW WAS GOING WEST AND WILL CONTINUE TO BACK TO THE SW LATE THIS
MORNING. DEEP MOISTURE SEEN WITHIN THE DGZ ALONG WITH A STRONG
OMEGA FOR THE CLASSIC BULLS-EYE WHICH SHOULD RESULT IN LARGER FLAKES
AND FAVORABLE ACCUMULATION RATES BY LATE MORNING/EARLY AFTERNOON.
INCREASED SNOW TOTALS FOR PORTIONS OF THE NW CWA AS THIS AREA SHOULD
SEE THE BEST SYNOPTIC/LE COMBO. FEEL WE WILL SEE A FEW 5-6 INCH
REPORTS FROM THIS ONE. THE HIGHEST TOTALS SHOULD OCCUR WHERE
OROGRAPHIC LIFT ALSO PITCHES IN...OVER NORTHERN NEWAYGO AND LAKE
COUNTIES.
AS THE WAVE PASSES EAST THE FLOW WILL PIVOT TO THE WNW TOWARD
NIGHTFALL...THEN CONTINUE TO PIVOT TO THE NNW BY LATE EVENING. THIS
WILL SPRAY MUCH OF THE WESTERN HALF WITH SNOWFALL THIS EVENING.
THEN INVERSION HEIGHTS CRASH TOWARD MIDNIGHT WHEN THE SNOW WILL
DIMINISH.
ANOTHER NORTHERN STREAM SYSTEM MOVES IN FOR SATURDAY. THIS APPEARS
TO BE A WEAKER SYSTEM THAT SHOULD ONLY PUT DOWN MINIMAL SNOWS...LESS
THAN AN INCH...AND MAINLY NORTH OF I-96. H8 TEMPS WARM BY THEN...SO
IT APPEARS THIS SYSTEM WILL NOT HAVE MUCH LAKE EFFECT POTENTIAL.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 343 AM EST THU NOV 28 2013
THE LONG TERM PERIOD WILL BE PREDOMINATELY DRY WITH TEMPERATURES
CLOSE TO NORMAL. SFC HIGH PRESSURE TO OUR NORTH OVER ONTARIO WILL
PROVIDE MICHIGAN WITH A DRY/COOL EASTERLY FLOW OF AIR AND A
PREDOMINATELY FLAT/ZONAL FLOW ALOFT WILL RESULT IN A VERY LOW
POTENTIAL FOR ANY SIGNIFICANT SYSTEMS.
THE UPPER FLOW DOES BEGIN TO AMPLIFY FOR THE MIDDLE TO LATE PART OF
NEXT WEEK WITH A LONG WAVE TROUGH DEVELOPING OVER THE WRN UNITED
STATES. SO THE PATTERN SHOULD BECOME MORE ACTIVE FOR SW MI BY NEXT
THURSDAY... BUT CURRENTLY IT LOOKS LIKE RAIN WOULD BE THE MAIN
PRECIP TYPE.
THE COLD FRONT WHICH PASSES THROUGH ON SATURDAY NIGHT BRINGS DOWN H8
AIR NEAR -10C. THIS SHOULD BE COLD ENOUGH TO GENERATE SOME LAKE
EFFECT CLOUDINESS AND LIGHT SNOW SHOWERS OR FLURRIES. INITIALLY ON
SUNDAY THE FLOW IS NORTHERLY WHICH SUPPORTS SOME LIGHT SNOW ACROSS
PORTIONS OF MASON AND OCEANA COUNTIES. THEN FOR SUNDAY NIGHT THROUGH
TUESDAY THE LOW LEVEL FLOW IS MORE EASTERLY WHICH MEANS MOST OF THE
AREA WILL BE DRY ALTHOUGH SOME FLURRIES FROM LAKE HURON MAY MAKE IT
INLAND TOWARD THE CLARE AREA.
THE DRY LOW LEVEL EAST FLOW AND SURFACE RIDGING MAY DELAY/FEND OFF
INCOMING WAA PRECIP NEXT WEDNESDAY BUT MAY ALSO RESULT IN A WINTRY
MIX AT THE PRECIP ONSET WED NIGHT DUE TO EVAPORATIVE COOLING/WET
BULB EFFECTS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 657 AM EST THU NOV 28 2013
IFR VSBYS IN SNOW ARE LIKELY AT MKG/GRR/LAN THROUGH MID MORNING
WITH MVFR TYPE VSBYS EXPECTED THEREAFTER. CONDITIONS SHOULD
IMPROVE TO VFR TONIGHT AS THE SNOW ENDS.
BASED ON WHERE THE SRN EDGE OF THE SNOW IS SETTING UP... THERE IS
A HIGH PROBABILITY OF VFR CONDITIONS WITH NO SNOW TODAY ALONG THE
I-94 CORRIDOR REGION INCLUDING AZO/BTL/JXN.
&&
.MARINE...
ISSUED AT 343 AM EST THU NOV 28 2013
EXTENDED THE SCA THROUGH TODAY AS THE SW FLOW REMAIN BRISK. AFTER A
CALMER PERIOD FOR TONIGHT AND FRIDAY...WE MAY NEED ANOTHER SCA BY
FRIDAY NIGHT AS SSW WINDS INCREASE.
&&
.HYDROLOGY...
ISSUED AT 343 AM EST THU NOV 28 2013
PCPN WILL BE ALL SNOW THROUGH THE SHORT TERM WITH MINIMAL MELTING...
SO NO HYDRO IMPACTS ARE EXPECTED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
MIZ037>040-043>046-050-051-056-057-064.
FLOOD WATCH THROUGH SATURDAY EVENING FOR MIZ045.
LM...NONE.
&&
$$
UPDATE...COBB
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1136 AM CST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 AM CST THU NOV 28 2013
MAIN ISSUE FOR THE SHORT TERM IS HOW LONG WILL IT TAKE FOR THE
CLOUDS TO CLEAR OUT TODAY. A 1018MB SFC LOW HAS BEEN MAKING SLOW BUT
STEADY PROGRESS ACROSS NRN IOWA OVERNIGHT AND WILL CONTINUE ON A
TRACK TOWARD SRN LAKE MICHIGAN BY THE AFTERNOON. AN INVERTED SFC
TROUGH HAS BEEN WORKING EAST ACROSS MN IN CONCERT WITH THE IOWA LOW
AND HAS HELPED MAINTAIN THE STRATUS NORTH OF THE LOW. BEHIND THIS
INVERTED TROUGH...ANOTHER CANADIAN HIGH IS BUILDING SOUTH ACROSS THE
DAKOTAS. RH TIME-HEIGHT PROFILES SHOW PLENTY OF DRYING AND
SUBSIDENCE OCCURRING AS THIS HIGH MOVES IN...WHICH IS WHY THE
QUESTION WITH THE CLOUDS IS HOW LONG DO THEY STICK AROUND. FOR
NOW...HAVE A RATHER CLOUDY FORECAST THROUGH 18Z...BUT QUICKLY START
TO IMPROVE THINGS FROM WEST TO EAST THIS AFTERNOON...IN LINE WITH
WHAT THE RAP 925-850 MB RH SHOWS.
ALTHOUGH THERE IS CURRENTLY A SEA OF LIGHT SNOW REPORTS ACROSS NRN
MN AND NODAK...THESE ARE NOT EXPECTED TO MAKE IT INTO THE MPX AREA.
THE REASON FOR THIS IS THAT SFC TEMPERATURES WHERE THE SNOW IS BEING
REPORTED RIGHT NOW ARE ALL IN THE LOW TO MID TEENS...WHICH MEANS UP
THERE...THE DENDRITIC GROWTH ZONE IS DOWN AT THE SURFACE AND EXTENDS
UP THROUGH THE CLOUD LAYER. ADD IN THE WEAK LIFT ALONG/AHEAD OF THE
INVERTED TROUGH WITH A DGZ ALL THE WAY DOWN TO THE SURFACE AND YOU
END UP WITH THE SCENARIO WHERE ALL CLOUDS HAVE SNOW. COMING DOWN TO
CENTRAL/SRN MN...SFC TEMPS DOWN HERE ARE ALL IN THE UPPER
TEENS/LOWER 20S...OUTSIDE OF THE DGZ. THE SHALLOWER DGZ THAT DOES
NOT EXTEND TO THE SFC HAS ALLOWED THE CLOUDS DOWN HERE TO REMAIN
SNOW FREE. CAA AT THE MOMENT IS NOT STRONG ENOUGH TO COOL OUR SFC
TEMPS DOWN INTO THE DGZ BEFORE WE START GETTING SOME SOLAR
HEATING...SO DO NOT ANTICIPATE THE SNOW/FLURRY REPORTS TO MAKE IT
MUCH FARTHER SOUTH THAN THEY CURRENTLY ARE.
THE COMBINATION OF WEAK CAA AND CLOUD COVER WILL AGAIN LIMIT THE
DIURNAL TEMPERATURE INCREASE AGAIN TODAY...WITH TEMPERATURES THIS
AFTERNOON ONLY EXPECTED TO INCREASE ABOUT 5 OR 10 DEGREES ABOVE
THEIR CURRENT VALUES THIS MORNING. TONIGHT...YET ANOTHER SFC RIDGE
AXIS WILL BE CENTERED ACROSS THE AREA...RESULTING IN ANOTHER NIGHT
WITH LOWS IN THE SINGLE DIGITS TO LOWER TEENS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 250 AM CST THU NOV 28 2013
THE LONG TERM WILL BEGIN TRANQUIL BUT WILL LIKELY END RATHER
ACTIVE AS A MAJOR PATTERN SHIFT UNFOLDS. HIGH PRESSURE OVER THE
GREAT LAKES WILL SLIDE EAST FRIDAY WITH WAA COMMENCING AT THE
START OF THE PERIOD. BREEZY SOUTHEAST WINDS WILL BRING HIGHS BACK
TO WHERE THEY SHOULD BE IN THE UPPER 20S TO MID 30S.
A WEAK CLIPPER SYSTEM WILL DIVE SOUTHEAST ACROSS NORTHERN LAKE
SUPERIOR FRIDAY NIGHT AND EARLY SATURDAY. FORECAST SOUNDINGS SHOW
SUFFICIENT MOISTENING IN THE LOWER LEVELS AFTER MIDNIGHT TO
SUPPORT A CHANCE OF FREEZING DRIZZLE OR FLURRIES OVER WESTERN
WISCONSIN. HOWEVER...KEPT PROBABILITIES RATHER LOW DUE TO THE
SOURCE REGION OF THIS MOISTURE BEING FROM THE SPRAWLING EASTERN
CONUS HIGH PRESSURE SYSTEM THAT DROVE A COLD FRONT THROUGH THE
GULF AND CUBA. NEEDLESS TO SAY...NOT A WHOLE LOT OF MOISTURE TO BE
FOUND ANYWHERE NEARBY.
SURFACE RIDGING WILL RETURN SATURDAY AND SUNDAY WITH TEMPERATURES
REMAINING NEAR NORMAL. MEANWHILE...A POTENT UPPER LOW TRAVERSING
ALASKA WILL DIVE SOUTHEAST ALONG THE BRITISH COLOMBIAN COAST INTO
THE PACIFIC NORTHWEST AND THE CENTRAL ROCKIES BY THE MIDDLE OF
NEXT WEEK. THIS WILL BE REPLACED WITH A 570DM RIDGE OVER ALASKA
MONDAY AND BUILDING HEIGHTS ACROSS THE CENTRAL AND EASTERN CONUS
FOR LATE WEEK. A SIZABLE CHUNK OF ARCTIC AIR WILL DISLODGE FROM
THE POLAR VORTEX AND SINK SOUTH TOWARD THE NORTHERN CONUS BY LATE
IN THE LONG TERM. FOLLOWED THE ECMWF/GEM/GFS ENSEMBLE SOLUTION
WITH A MORE ZONAL LOOK ACROSS THE NORTHERN TIER OF STATES AS
OPPOSED TO THE OPERATIONAL GFS WHICH SEEMED TOO AMPLIFIED DURING MID
TO LATE WEEK.
SOUTHERLY FLOW AHEAD OF THE WESTERN TROUGH AND MODEST ISENTROPIC
LIFT IN THE PRESENCE OF INCREASING MID LEVEL MOISTURE LOOKS
INCREASINGLY LIKELY WILL ALLOW FOR PERIODS OF LIGHT SNOW ALONG AN
EAST-WEST STATIONARY BOUNDARY FROM SUNDAY NIGHT THROUGH TUESDAY
NIGHT. DUE TO A SURFACE HIGH ANCHORED TO THE NORTH...EASTERLY
SURFACE FLOW WILL BRING A CONTINUED SUPPLY OF DRY BOUNDARY LAYER
AIR AND THUS AMOUNTS WILL BE LIGHT DURING THIS PERIOD.
SURFACE LOW ORGANIZING TO THE LEE OF THE ROCKIES IN ADVANCE OF
THE ROCKIES TROUGH MAY EJECT NORTHEAST TOWARD THE GREAT LAKES IN
THE WEDNESDAY NIGHT/THURSDAY TIMEFRAME. ECMWF BRINGS A PRETTY
IMPRESSIVE SYSTEM THROUGH WITH SIGNIFICANT ACCUMULATING SNOW. GEM
IS A BIT FURTHER SOUTH. REGARDLESS...FOLLOWING THIS POTENTIAL
STORM WILL BE AN EXPANSIVE INTRUSION OF ARCTIC AIR FOR MOST OF THE
CENTRAL AND WESTERN CONUS. THIS SIGNAL HAS BEEN SOLID IN CLIMATE
FORECASTING MODELS FOR WEEKS NOW AND AS CPC POINTS OUT IN THEIR
6-10 AND 8-14 DAY OUTLOOKS...PROBABILITY OF OCCUR RANCE IS VERY
HIGH. IF WE CAN GET A SNOWPACK DOWN BEFORE THIS ARRIVES...TEMPS
COULD BE 20-30+ DEGREES BELOW AVERAGE FOR EARLY DECEMBER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1120 AM CST THU NOV 28 2013
VFR/MVFR CIGS MOVING SOUTHWARD ACROSS EASTERN MN MAY ALLOW FOR
SOME CIGS ARND 2.5 TEMPORARY THIS AFTN. THE BEST CHC OF MVFR CIGS
WILL OCCUR AT KSTC/KRNH DURING THE EARLY AFTN. ELSEWHERE...MORE
SCATTERED CLDS ARE EXPECTED. BY 22Z...ANY MINOR DAYTIME HEATING
WILL QUICKLY ERODE THE CLDS WITH ONLY CIRRUS EXPECTED AFT 00Z.
WINDS WILL QUICKLY BECOME NEAR CALM OVERNIGHT...BEFORE SHIFTING TO
THE S/SSE BY DAWN AND INCREASE TO 14-16 KTS IN WESTERN MN...AND
ARND 12 KTS IN EASTERN MN.
KMSP...
MVFR CIGS AS CLOSE AS KMIC WHICH MAY AFFECT THE AIRPORT GROUNDS
DURING THE EARLY AFTN HRS. BEST TIME FRAME WILL OCCUR BETWEEN
18-20Z WITH CIGS ARND 2.5K. OTHERWISE...SKIES WILL QUICKLY BECOME
CLR THIS EVENING WITH CIRRUS MOVING IN AFT MIDNIGHT. GUSTY WINDS
ARND 14-16 KTS THIS AFTN WILL BECOME CALM AND SHIFT TO THE SE BY
MORNING...BECOMING GUSTY AGAIN BY THE AFTN.
/OUTLOOK FOR KMSP/
SAT...VFR. SW WINDS AT 5-10KTS BECOMING W/NW DURING THE AFT/EVE.
SUN...VFR...POSSIBLY MVFR CIGS LATE WITH -SN. WINDS E/SE AT 5KTS.
MON...VFR WITH CHC OF MIX PREC LATE WITH MVFR CIGS. SE WNDS 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...BORGHOFF
AVIATION...JLT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1144 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 913 AM CST THU NOV 28 2013
WITH THICK STRATUS EVIDENT ON SATELLITE IMAGERY AND LATEST RAP
COMING IN WITH PESSIMISTIC CONDITIONS FOR THE REST OF THE
DAY...WENT AHEAD AND FURTHER INCREASED CLOUD COVER FROM PREVIOUS
UPDATE AS WELL AS DROPPED FORECAST HIGH TEMPERATURES ABOUT 5
DEGREES ACROSS THE BOARD. OTHERWISE...NO ADDITIONAL CHANGES
NECESSARY AT THIS TIME.
UPDATE ISSUED AT 749 AM CST THU NOV 28 2013
BASED ON LATEST SHORTWAVE IR SATELLITE AND MODEL TRENDS...
ANTICIPATE WE WILL NEED TO MAKE SOME SUBSTANTIAL CHANGES TO THE
FCST TODAY AND POSSIBLY INTO TONIGHT AND TOMORROW. THESE CHANGES
WILL INVOLVE MORE CLOUDS AND COOLER TEMPS...PROBABLY NOT BECOMING
AS WARM AS THOUGHT THE LAST FEW DAYS AND WE SAW THIS AS A
POTENTIAL OPTION EARLIER THIS WEEK. IT/S TOUGH TO FCST FAR IN
ADVANCE THOUGH.
THERE IS AN EXTENSIVE BANK OF STRATUS RACING S TO THE KS-NEB
BORDER AT THIS TIME AND IT EXTENDS ALL THE WAY UP INTO THE
CANADIAN PRAIRIES. BELIEVE THIS IS GOING TO BE A FCST PROBLEM THRU
SUNSET TOMORROW AS IT WILL BE STUCK IN A THERMAL TROF /COLD
POCKET/ AND WILL RESIST EROSION. WE REALLY NEED WARM AIR ADVECTION
TO GET RID OF IT AND THAT WILL NOT HAPPEN UNTIL LATE TONIGHT OR
TOMORROW.
SO THE FCST SKY HAS BEEN TURNED SIGNIFICANTLY MORE PESSIMISTIC
THRU MIDDAY AND EXPECT WE WILL NEED TO PUSH THIS FURTHER INTO THE
AFTERNOON PENDING THE LATEST SATELLITE TRENDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST THU NOV 28 2013
OVERNIGHT UPPER AIR ANALYSIS INDICATES MID TO UPPER LEVEL
TROUGHING OVER THE EASTERN CONUS...WITH A RIDGE OVER THE WEST AND
A MID LEVEL LOW OVER THE PACIFIC OFF THE CALIFORNIA COAST. A
SUBTLE MID LEVEL PERTURBATION IS ALSO NOTED OVER SOUTHERN
MINNESOTA...MOVING SOUTHEAST. MID TO UPPER LEVEL JET ENERGY
EXTENDS FROM SOUTH CENTRAL CANADA...SOUTHEAST INTO THE CENTRAL
CONUS...AND FINALLY EAST AND NORTHEAST ALONG THE EASTERN CONUS
INTO SOUTHEASTERN CANADA. MID TO UPPER LEVEL FLOW OVER OUR AREA
MAXES OUT AT AROUND 70KTS BETWEEN 300MB AND 200MB PER 00Z SOUNDING
DATA FROM KLBF AND KOAX. WATER VAPOR IMAGERY INDICATES INCREASED
VALUES OF MID LEVEL MOISTURE EXTENDING ALONG THE BACK SIDE OF THE
WEST COAST RIDGE...AS WELL AS FROM THE PACIFIC EASTWARD INTO
MEXICO AND THE SOUTHERN PLAINS. MID LEVEL MOISTURE OVER OUR AREA
HOWEVER REMAINS FAIRLY LIMITED. AT THE SURFACE...AN AREA OF LOW
BAROMETRIC PRESSURE EXISTS OVER NORTHWEST IOWA JUST AHEAD OF THE
AFOREMENTIONED MID LEVEL PERTURBATION...WITH AN ASSOCIATED COLD
FRONT EXTENDING FROM WESTERN IOWA INTO SOUTHEASTERN NEBRASKA AND
NORTHERN KANSAS. THIS FRONT HAS CLEARED MOST ALL OF OUR CWA AND AS
A RESULT...THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM
THE NORTH/NORTHWEST.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST NORTHWESTERLY MID TO UPPER LEVEL FLOW WILL PERSIST OVER
OUR AREA THROUGH THE NEXT 24 HOURS AS THE EASTERN CONUS TROUGH AND
WESTERN CONUS RIDGE BOTH TREK EAST. THE MID LEVEL
PERTURBATION...CURRENTLY OVER SOUTHERN MINNESOTA...IS EXPECTED TO
CONTINUE MOVING SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH NO
OTHER MID LEVEL SHORTWAVES/PERTURBATIONS EXPECTED TO IMPACT THE
REGION. AT THE SURFACE...THE AREA OF LOW BAROMETRIC
PRESSURE...CURRENTLY OVER NORTHWEST IOWA...SHOULD ALSO CONTINUE
MOVING TO THE EAST/SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH THE
ASSOCIATED LOW LEVEL BAROCLINIC ZONE PUSHING FARTHER
SOUTH/SOUTHEAST ACROSS THE PLAINS. THE LOW LEVEL WIND FIELD ACROSS
OUR AREA SHOULD REMAIN FROM THE NORTH/NORTHWEST THROUGH MUCH OF
TODAY AS A RESULT. THAT BEING SAID...GUIDANCE SUGGESTS THE PASSAGE
OF A SURFACE RIDGE TO EAST SHOULD ALLOW FOR LOW LEVEL RETURN FLOW
ACROSS OUR AREA DURING THE OVERNIGHT HOURS TONIGHT.
WITH AN OVERALL LACK IN OMEGA EXPECTED OVER OUR AREA...DRY
CONDITIONS ARE CURRENTLY FORECAST THROUGH THE NEXT 24 HOURS.
SATELLITE IMAGERY INDICATES A BAND OF STRATUS OVER MUCH OF THE
NORTHERN PLAINS THIS MORNING AND THIS STRATUS IS ADVANCING TO THE
SOUTH...ABOUT 150 MILES NORTH OF THE AFOREMENTIONED SURFACE FRONT.
GUIDANCE FROM THE NAM AND RAP BOTH SHOW THIS STRATUS...WITH HIGH
RELATIVE HUMIDITY VALUES AT 925MB NOTED ON PLAN VIEW
MAPS...INFILTRATING OUR NORTH/NORTHEASTERN CWA JUST PRIOR TO
SUNRISE THIS MORNING...BUT DISSIPATING POST-SUNRISE AS DIABATIC
HEATING RESULTS IN INCREASED BOUNDARY LAYER HEIGHT AND MIXING.
WENT AHEAD AND PLAYED PRETTY CLOSE TO NAM AND RAP GUIDANCE FOR THE
CLOUD FORECAST THROUGH THE FIRST PART OF THE SHORT TERM FORECAST
PERIOD...WITH THIS STRATUS EXPECTED TO IMPACT OUR NORTH/NORTHEAST
BY 10Z OR 11Z THIS MORNING...AND THEN DISSIPATE BY 15Z OR 16Z.
WITH LOW LEVEL RETURN FLOW INFILTRATING THE REGION TONIGHT...THERE
ARE INDICATIONS OF ISENTROPIC UPGLIDE AND SATURATION...PRIMARILY
ALONG THE 275-285K SURFACES...OVER THE HIGH PLAINS OF KANSAS AND
NEBRASKA. ALTHOUGH IT APPEARS MUCH OF OUR CWA SHOULD BE SPARED
FROM ANY STRATUS DEVELOPMENT THROUGH 12Z FRIDAY...925MB RELATIVE
HUMIDITY PLAN VIEW MAPS FROM THE NAM...OPERATIONAL GFS AND EC ALL
SUGGEST OUR EXTREME WEST/SOUTHWEST COULD ACTUALLY OBSERVE QUITE A
BIT OF CLOUD COVER TOWARDS SUNRISE FRIDAY AS THE EASTERN PERIPHERY
OF THE HIGH PLAINS STRATUS CLIPS THE AREA. WENT AHEAD WITH A
BROKEN CEILING ACROSS OUR EXTREME WEST/SOUTHWEST BY 12Z FRIDAY AS
A RESULT.
THE INTRUSION OF A COOLER LOW LEVEL AIRMASS BEHIND THE LOW LEVEL
BAROCLINIC ZONE SHOULD RESULT IN A COOLER DAY TODAY WHEN COMPARED
TO WEDNESDAY. HIGH TEMPERATURES GENERALLY IN THE MID 30S ACROSS
OUR NORTH...AND INTO THE MID 40S ACROSS OUR SOUTH...ARE FORECAST
FOR TODAY AS A RESULT. IT MIGHT OTHERWISE BE REASONABLE TO THINK
TONIGHT WILL BE COOLER WHEN COMPARED TO EARLY THIS MORNING...BUT
WITH LOW LEVEL RETURN FLOW EXPECTED TO INFILTRATE OUR AREA DURING
THE OVERNIGHT HOURS...OVERNIGHT LOWS TONIGHT SHOULD ACTUALLY BE
PRETTY CLOSE TO WHAT WE ARE EXPECTING EARLY THIS MORNING.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CST THU NOV 28 2013
THE FIRST PART OF THE LONG TERM FORECAST IS DRY WITH ABOVE NORMAL
TEMPERATURES...AFTER WHICH A MORE UNSETTLED...COLDER AND MORE
CHALLENGING FORECAST TAKES HOLD BY MID NEXT WEEK.
A TRANSITIONING WEST/NORTHWEST UPPER LEVEL FLOW WILL KEEP THE
REGION MAINLY DRY AND MILD THROUGH THROUGH THE REMAINDER OF THE
HOLIDAY WEEKEND. REGIONAL TRAVEL CONCERNS WILL BE NIL...AND BOTH
DAYTIME HIGHS AND NIGHTTIME LOWS WILL BE AT OR SLIGHTLY ABOVE
SEASONAL NORMALS. ONE NOTABLE WEATHER ELEMENT WILL THE WIND...OR
LACK THERE OF ON SATURDAY AND SUNDAY. THAT WILL HELP OFFSET ANY
COOLING FROM PASSING CLOUDS THROUGHOUT THE WEEKEND.
OVERALL...PRETTY NICE FOR THE END OF NOVEMBER. WARM ADVECTION
ASSOCIATED WITH WAVE ACROSS THE NORTHERN PLAINS SUNDAY WILL
THICKEN CLOUDS...BUT NOT TOO EXCITED ABOUT INCURRING ANY
MEASURABLE PRECIPITATION AT THIS POINT.
ACTUALLY THE MILD WEATHER WILL CONTINUE INTO THE FIRST PART OF
NEXT WEEK...ALTHOUGH THINGS WILL BE CHANGING AS UPPER LEVEL
HEIGHTS LOWER AND WE START TO SEE UPPER LEVEL LOW PRESSURE DEEPEN
IN THE GREAT BASIN REGION. AS THE LOW STRENGTHENS...AN INCREASING
SOUTH TO SOUTHEAST FLOW ACROSS THE CENTRAL/SOUTHERN PLAINS
DEVELOPS WHICH WILL KEEP TEMPERATURES ON THE MILD SIDE
MONDAY/TUESDAY. THERE IS SOME MODEL LIKENESS IN OVERALL
TRENDS...BUT VERY UNEASY IN TRYING TO PIN DOWN ANY SPECIFIC
DETAILS FOR NEXT WEEKS FORECAST AT THIS POINT. WE HAVE BEEN
ANTICIPATING A COLD AIR PUSH NEXT WEEK...AND THAT STILL LOOKS ON
TRACK FOR ABOUT WEDNESDAY...BUT THE COLD AIR PLUNGE COMES IN
PIECES WITH THE COLDEST AIR NOT LIKELY TO MAKE IT INTO THE AREA
UNTIL LATER NEXT WEEK. MODELS SUGGEST HEAVIEST PRECIPITATION
TRENDS WILL LIKELY BE ACROSS THE DAKOTAS AT THIS POINT...WITH ONLY
SMALL CHANCES FOR RAIN OR RAIN/SNOW MIX IN THE FORECAST AT THIS
POINT AS THE SYSTEM APPROACHES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1140 AM CST THU NOV 28 2013
A BREAK IN MVFR STRATUS IS EVIDENT ON LATEST SATELLITE
IMAGERY...BUT EXPECT THIS STRATUS TO RAPIDLY FILL BACK IN BY ABOUT
28/20Z...AND PERSIST THROUGH THE LATE AFTERNOON OR EARLY EVENING
HOURS. WINDS WILL GENERALLY REMAIN NORTHERLY THROUGH THE AFTERNOON
HOURS...EVENTUALLY BECOMING LIGHT AND VARIABLE AS THE SURFACE HIGH
TRACKS SOUTH ACROSS THE MISSOURI RIVER VALLEY. SOUTHERLY WINDS ARE
EXPECTED TO INCREASE IN RETURN FLOW AROUND THIS HIGH PRESSURE
SYSTEM ON FRIDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...ROSSI
SHORT TERM...NOAA/NWS/BRYANT
LONG TERM...NOAA/NWS/MORITZ
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS BISMARCK ND
306 PM CST THU NOV 28 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 306 PM CST THU NOV 28 2013
THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD WILL BE SKY COVER
TONIGHT AND IMPACT ON TEMPERATURES.
PORTIONS OF THE STRATUS DECK HAVE ERODED ACROSS THE FORECAST AREA
THIS AFTERNOON. RAP 925MB RELATIVE HUMIDITY HAS THIS MODELED
RELATIVELY WELL AND SUGGEST THAT STRATUS SHOULD FILL BACK IN THIS
EVENING AND OVERNIGHT. TEMPERATURES WILL LIKELY DROP QUICKLY THIS
EVENING IN CLOUD FREE AREAS...BEFORE THE STRONGER SE WINDS
DEVELOP. THE STRONGER GRADIENT WILL BE LOCATED OVER THE WEST AND
HAVE KEPT OVERNIGHT LOWS RELATIVELY MILD...IN THE TEENS TO LOWER
20S. EAST/NORTHEAST PORTIONS OF THE FORECAST AREA...FROM THE
TURTLE MOUNTAINS THROUGH THE JAMES RIVER VALLEY...SHOULD BE ABLE
TO GET INTO THE SINGLE DIGITS. HOURLY TRENDS WILL LIKELY NEED TO
BE UPDATED THIS EVENING.
ON FRIDAY...STRONGER WARM AIR ADVECTION WILL KICK IN...WITH HIGHS
IN THE MID 20S NORTHEAST TO LOWER 40S SOUTHWEST.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 306 PM CST THU NOV 28 2013
THE HIGHLIGHT OF THE EXTENDED FORECAST IS THE RETURN OF ARCTIC AIR
AND THE POTENTIAL FOR WIDESPREAD ACCUMULATING SNOW NEXT WEEK.
THE 12 UTC GUIDANCE SUITE IS IN GOOD AGREEMENT ON A SIGNIFICANT
UPPER LEVEL LOW COMING ONSHORE TO THE PACIFIC NORTHWEST ON MONDAY.
THEREAFTER...UNCERTAINTY INCREASES IN REGARDS TO THE EVOLUTION AND
PROPAGATION OF THIS LOW ACROSS THE INTERMOUNTAIN WEST AND
POTENTIALLY INTO THE NORTHERN PLAINS LATE TUESDAY AND INTO
WEDNESDAY. THE 12 UTC ECMWF CONTINUES THE TREND OF ITS PREVIOUS
RUNS OVER THE PAST 24 HOURS OF THE DEEPEST LOW YIELDING
SIGNIFICANT QPF AND SNOW ACROSS THE NORTHERN PLAINS TUESDAY INTO
WEDNESDAY. THE 12 UTC GFS HAS TRENDED MORE TOWARDS THE
ECMWF...HOWEVER...IS NOT AS DEEP WITH LESSER QPF...MUCH LIKE THE
12 UTC GEM. THE ECMWF HAS BEEN THE MOST CONSISTENT AND IS
SUPPORTED BY THE GEFS MEAN...AND FAVORED BY WPC. THUS...WILL
CONTINUE TO MONITOR THE POTENTIAL FOR ACCUMULATING SNOW NEXT WEEK.
NO MATTER THE MODEL...ARCTIC AIR IS FORECAST TO OVERTAKE THE
NORTHERN PLAINS ONCE AGAIN TUESDAY THROUGH THE END OF NEXT WEEK
WITH A PATTERN SHIFT TO BROAD WESTERN AND CENTRAL CONUS UPPER
LEVEL TROUGHING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 306 PM CST THU NOV 28 2013
EXPECT MAINLY MVFR CEILINGS THROUGH TONIGHT...WITH SOME PERIODS
THIS AFTERNOON WHEN CLOUDS SCATTER OUT...ESPECIALLY AT
KDIK/KJMS/KMOT. A FEW FLURRIES WILL PERSIST.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM/AVIATION...RP KINNEY
LONG TERM...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1234 PM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 1228 PM CST THU NOV 28 2013
TEMPERATURES HAVE BEEN SLOW TO RECOVER OVER PORTIONS OF NW MN
LIKELY A RESULT OF FRESH SNOW COVER AND LOWERED MAXIMUM
TEMPERATURES 3-5 DEGREES. TEMPERATURES ON TRACK ELSEWHERE WHERE
PARTIAL SOLAR HELPING THE SLIGHT RECOVERY EXPECTED. NO OTHER
CHANGES MADE TO ONGOING FORECAST.
UPDATE ISSUED AT 936 AM CST THU NOV 28 2013
MAIN CHALLENGE TODAY WILL BE CLOUD TRENDS AND TEMPERATURES. LATEST
SATELLITE IMAGERY SHOWING A GENERAL DECREASE IN CLOUD COVER ACROSS
THE REGION BEST DEPICTED BY RAP MESO-MODEL. WILL CONTINUE WITH A
GRADUAL DECREASE IN CLOUDS THROUGH THE MORNING BASED ON RAP
GUIDANCE AND CURRENT TRENDS. AT THIS POINT WITH EXPECTED PARTIAL SOLAR
WILL HOLD WITH TEMPERATURES FOR NOW. ONLY CHANGES WERE MINOR CLOUD
TREND ADJUSTMENTS.
UPDATE ISSUED AT 641 AM CST THU NOV 28 2013
CLOUDS CONTINUE TO BE A CHALLENGE. RAP/HRRR CIG GUIDANCE
INITIALIZES WITH CLEAR SKIES...BUT THEN DEVELOPS LOW CIGS DURING
THE AFTERNOON HOURS (LIKELY CU...LOW CONVECTIVE TEMPS) WHICH GET
TRAPPED UNDER THE RIDGE TONIGHT. RAP 925MB-850MB RH FIELD
ACTUALLY INDICATES THE DRYING THAT IS WORKING THROUGH THE
VALLEY...AND PROBABLY IS CLOSEST TO THE TRUTH. ADJUSTED THE SKY
GRIDS FOR CURRENT OBSERVATIONS AND LATEST RAP 925MB-850MB RH. NO
MAJOR CHANGES YET UNTIL MORE CONFIDENCE CAN BE OBTAINED WITH WHAT
EVER THE CLOUDS WILL DO TODAY.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
NORTHWEST FLOW ALOFT WILL CONTINUE INTO FRIDAY...WITH ANOTHER
SHORTWAVE EXPECTED FRIDAY INTO FRIDAY NIGHT. 00Z MODELS INDICATE
THAT THIS NEXT SHORTWAVE WILL TRACK FURTHER NORTH THAN THE ONE
YESTERDAY...KEEPING ACCUMULATING SNOWFALL OUTSIDE OF THE FA.
FOR TODAY...THE REGION WILL BE BETWEEN SHORTWAVES AS HIGH PRESSURE
BUILDS FROM THE NORTH. THIS WILL LEAVE CLOUD TRENDS AS THE MAIN
CHALLENGE. 09Z SATELLITE IMAGERY SHOWS CLEARING WORKING INTO THE
NORTHERN VALLEY. MODELS ARE STRUGGLING WITH THE CURRENT CLOUD
COVER...ALTHOUGH THE 07Z RAP IS CLOSEST WHEN LOOKING AT THE 925MB-
850MB RH FIELD. THIS MODEL INDICATES THAT CLEARING WILL CONTINUE
TO MOVE DOWN THE VALLEY...WITH CLOUDS DISSIPATING ALONG BOTH
EDGES THROUGH THE DAY. THIS SCENARIO MAKES SOME SENSE WITH THE
HIGH BUILDING INTO THE REGION. HOWEVER...CONVECTIVE TEMPS WILL BE
IN THE TEENS UNTIL LATE AFTERNOON...WHICH COULD LEAD TO
REDEVELOPMENT WITHIN CLEARING AREAS. DID DELAY THE CLEARING...BUT
REMAINED OPTIMISTIC THAT MOST AREAS WILL CLEAR THIS AFTERNOON.
ALSO...CONSIDERING CURRENT CONDITIONS...MENTIONED FLURRIES WITHIN
EXPECTED CLOUDY AREAS.
MIN TEMPS TONIGHT VERY DEPENDENT ON WHETHER OR NOT WE GET RID OF
THE CLOUDS TODAY. IF WE DO CLEAR...THERE WILL LIKELY WILL BE A
QUICK DROP THIS EVENING BEFORE RETURN FLOW KICKS IN AND TEMPS
BECOME STEADY AFTER MIDNIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
FRIDAY NIGHT-SATURDAY NIGHT...HIGH PRESSURE MOVING THROUGH SHOULD
LEAD TO DRY WEATHER. NOT SURE ABOUT CLOUD COVER (CONSIDERING
CURRENT CONDITIONS FOLLOWING A SHORTWAVE). CURRENT THOUGHT IS THAT
SINCE THE FRIDAY SHORTWAVE WILL TRACK FURTHER NORTH THAN THE
CURRENT SYSTEM...SHOULD BE LESS CLOUDS. ALSO...ANTICIPATE A WARMER
AIRMASS.
SUNDAY-WEDNESDAY...DETERMINISTIC MODEL RUNS CONTINUE TO SUGGEST A
MORE ACTIVE PATTERN TAKING SHAPE NEXT WEEK AS AN UPPER WAVE
CURRENTLY ACROSS ALASKA DIVES SOUTHWARD INTO THE WESTERN CONUS
DURING THE FIRST HALF OF NEXT WEEK...WITH ZONAL FLOW TRANSITIONING
TO SOUTHWEST FLOW ALOFT DOWNSTREAM ACROSS THE PLAINS. 00Z MODELS
SUGGEST THE POTENTIAL FOR SOME LIGHT SNOW WITH WARM ADVECTION LATER
SUNDAY INTO MONDAY. BEYOND THIS POINT...CONFIDENCE REGARDING ANY
PARTICULAR DETAILS IS VERY LOW...WITH SIGNIFICANT DIFFERENCES AMONG
MODELS IN HANDLING THE UPPER LONGWAVE TROUGH AND TIMING/PLACEMENT
OF EMBEDDED SHORTWAVE TROUGHS. THE LOW TO MID-LEVEL BAROCLINIC ZONE
WILL REMAIN POSITIONED ACROSS THE NORTHERN PLAINS THROUGH MID-WEEK
BEFORE ADVANCING SOUTHWARD. ANY WAVE EJECTING OUT OF THE BROADER
TROUGH TO THE WEST ALONG THIS BAROCLINIC ZONE WILL NEED TO BE
WATCHED FOR SFC CYCLONE DEVELOPMENT...WITH THE 00Z ECMWF INDICATING
A MORE SIGNIFICANT WAVE FOR THE MIDDLE OF THE WEEK. GIVEN THE VARIED
MODEL SOLUTIONS...CONTINUED WITH BROAD BRUSHED SLIGHT/CHANCE POPS
THROUGH MUCH OF THE PERIOD. TEMPS THROUGH MID-WEEK LOOK TO BE
SEASONABLE BEFORE COLDER AIR ARRIVES LATE IN THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1228 PM CST THU NOV 28 2013
MVFR CEILINGS WITH PATCHY LIGHT SNOW/FLURRIES CONTINUE ACROSS THE FAR
EASTERN PORTIONS OF THE FA...THIS INCLUDES KTVF AND KBJI.
OTHERWISE...SKIES HAVE UNDERGONE A CLEARING TREND IN THE HEART OF
THE RED RIVER VALLEY AND SOUTHERN PORTIONS OF THE FA. THESE TRENDS
SHOULD CONTINUE FOR THE REMAINDER OF THE DAYLIGHT HOURS. CLOUD
COVER IS THEN EXPECTED TO INCREASE AGAIN ACROSS THE NORTHERN FA
AFTER 00Z AND CONTINUING OVERNIGHT. SURFACE WINDS WILL SLACKEN IN
THE EVENING AND THEN BEGIN TO TURN AROUND OUT OF THE SOUTHEAST AS
THE SURFACE RIDGE PASSES TO THE EAST OF THE REGION. THE WINDS
SHOULD INCREASE AFTER SUNRISE ON FRIDAY AND GUST TO AROUND 20
KNOTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...TG
LONG TERM...TG/MAKOWSKI
AVIATION...BRAMER
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1150 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 949 AM CST THU NOV 28 2013
CLOUDS ARE PROVIDING THE GREATEST CHALLENGE FOR THE SHORT TERM
TODAY. FAIRLY EXTENSIVE CLOUDS PRESENT EARLY THIS MORNING HAVE
DIMINISHED IN COVERAGE EAST...BUT ARE FAIRLY SOLID FOR THE TIME
WEST. BASED ON KABR/KBIS MORNING RAOBS...THESE CLOUDS ARE FAIRLY
SHALLOW...BUT IMPRESSIVELY TRAPPED BELOW INVERSION...MAKING THE
DISSIPATION LIKELY TO BE A RESULT OF DRYING AND LIMITED HEATING
BELOW INVERSION AS WELL AS AN ADVECTIVE COMPONENT. RAP ON THE RIGHT
TRACK...BUT TOO PESSIMISTIC TOWARD I 29 CORRIDOR. AT THIS TIME...
CLOUDS LOOK TO BE FAIRLY TOUGH TO SHAKE IN THE WEST/SOUTHWEST CWA
WHILE THOSE AREAS IN ADVANCE OF THE LOW LEVEL RIDGE AXIS FROM
AROUND I29 EASTWARD ARE CERTAIN TO FIND A MIX OF CLOUDS AND SUN
THROUGH MIDDAY AND THEN TRENDING TOWARD MORE SUN. BASED ON TEMPS
ON CLOUD BEARING LEVEL AS WELL AS UPSTREAM OBSERVATIONS...HAVE
ADDED IN A FEW FLURRIES TO AREAS AS FAR SOUTH AS AROUND KFSD...BUT
EXPECT STRONGER COVERAGE OF LOW REFLECTIVITIES ON KABR RADAR TO
DWINDLE SOMEWHAT WITH INCREASING DISTANCE FROM WEAK TERRAIN
SUPPORT. EARLIER FLURRIES IN SW MN COULD HAVE IMPACTED SOMEWHAT
MORE RAPID DISSIPATION IN CLOUDS...AND MAY ALSO INFLUENCE THE
CLEARING TREND. TEMPS ALSO CHALLENGING WITH CONTINUED LOW LEVEL
COLD AIR ADVECTION...BUT TEMPS ALREADY REACHING INDICATED MIXING
POTENTIAL UNDER CLOUDY AREAS BY MID MORNING. PROBABLY NOT MUCH
ROOM TO WARM MORE THAN A FEW DEGREES ANYWHERE TODAY...MOST SO IN
AREAS WITH SUNSHINE TO THE EAST. UPDATES OUT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM CST THU NOV 28 2013
CURRENT SURFACE ANALYSIS SHOWS THE FRONTAL BOUNDARY HAVING PUSHED
THROUGH OUR CWA EARLY THIS MORNING...WITH AN AREA OF STRATUS
STREAMING INTO OUR WESTERN CWA BEHIND THE EXITING SYSTEM. THE
SURFACE RIDGE AXIS PRESENTLY LOCATED THROUGH THE WESTERN PORTIONS OF
THE DAKOTA WILL SLIDE TO THE SOUTH AND EAST TODAY...AND WITH DRYING
AND SUBSIDENCE LOOKING FOR THE LOW CLOUDS TO THIN OUT ACROSS THE
AREA BY LATE MORNING OR EARLY AFTERNOON. OTHERWISE...IT WILL BE
BREEZY DURING THE EARLY PART OF THE DAY...ESPECIALLY IN THE
EAST...WITH COLD AIR ADVECTION AND A DECENT GRADIENT ACROSS THE
AREA...THEN TAPERING DOWN IN THE AFTERNOON AS HIGH PRESSURE BUILDS
IN AND THE GRADIENT RELAXES AND ML WINDS DECREASE. THERMAL PROFILES
DO COOL A BIT TODAY...THOUGH NOTHING TOO EXTREME WITH HIGHS STILL
MAKING IT INTO THE MID 20S TO LOWER 30S FROM NORTHEAST TO SOUTHWEST
RESPECTIVELY.
THE HIGH PRESSURE MOVES QUICKLY TO THE EAST TONIGHT...AND WITH THAT
WINDS WILL TRANSITION TO SOUTHEASTERLY AND PICK UP LATER AT NIGHT.
IT WILL STILL BE A COLD NIGHT WITH LOWS IN THE UPPER SINGLE DIGITS
TO TEENS...WITH TEMPS STEADYING OUT OR RISING SOME LATE AT NIGHT AS
THE WINDS INCREASE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 520 AM CST THU NOV 28 2013
POTENT PACIFIC LOW DIVES INTO THE PACIFIC NORTHWEST FRIDAY AND
SATURDAY...SHIFTING THE INTERMOUNTAIN WEST RIDGING ITO THE PLAINS
STATES. A STRONG PUSH OF WARM AIR ADVECTION AND BREEZY SOUTHERLY
WINDS WILL BRING MILDER TEMPERATURES ON FRIDAY DESPITE SOME PASSING
MID AND HIGH CLOUDS FILTERING THE SUNSHINE. HIGHS WILL WARM TO
SLIGHTLY ABOVE NORMAL READINGS IN THE LOW 30S EAST TO THE MID 40S
WEST. A WEAK FRONT SAGS ACROSS THE FORECAST AREA FRIDAY NIGHT
THROUGH SATURDAY MORNING...BUT WITHOUT MOISTURE OR A REAL COLD AIR
PUSH BEHIND IT...CONDITIONS WILL REMAIN DRY AND MILD WITH HIGHS
MIXING INTO THE UPPER 30S TO MID 40S.
MUCH GREATER UNCERTAINTY SHOWS UP EARLY NEXT WEEK AS THE PACIFIC
TROUGH STRENGTHENS AND MOVES INTO THE NORTHERN ROCKIES. MODELS STILL
SHOWING SIGNIFICANT DIFFERENCES IN THE STRENGTH...TIMING AND TRACK
OF THE UPPER LOW. THE GFS FOLLOWS A MORE NORTHERLY TRACK WHILE THE
ECMWF IS SLOWER AND FURTHER SOUTH. FINALLY...THE CANADIAN DEPICTS A
MUCH WEAKER SYSTEM OVERALL WHICH GIVEN THE ENERGETIC NATURE OF THIS
SYSTEM SEEMS THE LEAST LIKELY.
INITIAL SHORTWAVE AHEAD OF THE MAIN SYSTEM SLIDES SOUTHEAST ACROSS
THE REGION AROUND THE SUNDAY NIGHT/MONDAY TIME FRAME. WITH THE GFS
RAPIDLY AMPLIFYING THE PAC NW TROUGH AND UPPER RIDGE AHEAD OF
IT...THIS WAVE IS WEAKER AND FASTER MOVING THAN THE ECMWF WHICH
DEVELOPS AN INVERTED TROUGH FEATURE OVER THE NORTHERN AND CENTRAL
PLAINS AND KEEPS IT IN THE PICTURE WELL INTO TUESDAY. SIGNIFICANT
DIFFERENCES IN TEMPERATURE PROFILES ALSO MAKE PRECIPITATION TYPES
DIFFICULT TO PINPOINT. TEMPERATURES LOOK TO REMAIN SEASONALLY MILD
THROUGH WEDNESDAY WITH MUCH COOLER READINGS ARRIVING LATE IN THE
WEEK. FOR NOW WILL KEEP MENTION OF BOTH RAIN AND SNOW. NOT MUCH
CONFIDENCE IN THE TIMING OF THE PRECIPITATION BUT CHANCES DO APPEAR
TO IMPROVE AS WE MOVE TOWARDS MID WEEK AS THE MAIN PACIFIC TROUGH
ADVANCES TOWARDS THE REGION. FOR NOW DID NOT ALTER THE ALLBLEND POPS
OR TEMPS MUCH GIVEN SUCH UNCERTAINTY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1149 AM CST THU NOV 28 2013
MVFR CEILINGS WILL CONTINUE ACROSS MUCH OF THE AREA EARLY THIS
AFTERNOON... BUT SHOULD GRADUALLY SEE COVERAGE BEGIN TO FAVOR
AREAS WEST OF THE JAMES RIVER VALLEY AFTER 21Z. REMAINDER OF THE
PERIOD SHOULD BE VFR...WITH EXCEPTION OF THOSE CEILINGS HANGING
UP IN THE FAR WEST. AT THIS POINT...IT IS ANTICIPATED THAT MOST OF
THE CEILINGS WILL DISSIPATE BEFORE RETURNING EASTWARD EARLY
FRIDAY...BUT COULD HAVE TO WATCH KHON FOR SOME MVFR CLOUDS AGAIN
BY AROUND 15Z.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHAPMAN
SHORT TERM...
LONG TERM...JM
AVIATION...CHAPMAN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1123 AM CST THU NOV 28 2013
.UPDATE...
SEE UPDATED AVIATION DISCUSSION BELOW.
THE MAIN FORECAST CHANGES THIS MORNING REVOLVE AROUND THE STRATUS
DECK THAT HAS SPREAD OVER THE REGION. MODELS ARE MUCH TO
OPTIMISTIC IN ERODING THE CLOUD DECK...SO ADJUSTED THE SKY GRIDS TO
KEEP THE WESTERN HALF OF THE CWA UNDER CLOUD COVER MUCH LONGER
THAN ORIGINALLY ANTICIPATED. ALSO EXTENDED THE FLURRIES MENTION
AS SEVERAL OBS HAVE REPORTED VERY LIGHT SNOW THIS MORNING. OVERALL
THE OTHER FORECAST FIELDS SEEM TO BE ON TRACK...TEMPERATURES WILL
REMAIN PRETTY STEADY THROUGH THE DAY...AND THE INHERITED FORECAST
TREND SEEMS TO BE REFLECTING THIS WELL.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
AN EXTENSIVE STRATUS DECK OVER THE REGION IS KEEPING TEMPERATURES
RELATIVELY MILD WITH CURRENT READINGS IN THE MID 20S. BASED ON THE
PAST FEW RUNS OF THE RUC...IT SEEMS UNLIKELY THIS STRATUS DECK
WILL DISSIPATE ANYTIME SOON. WOULD NOT BE TOO SURPRISED IF THESE
CLOUDS HANG AROUND THROUGH THIS AFTERNOON BEFORE DRIER AIR AT 925
MB MOVES IN FROM THE SOUTHWEST. OF COURSE THESE CLOUDS WILL MAKE
FORECASTING HIGH TEMPERATURES RATHER DIFFICULT. HAVE RELIED UPON
THE RUC MODEL WHICH SHOWS A SLIGHT COOL DOWN AROUND SUNRISE...THEN
A SLIGHT INCREASE BY 21Z.
HIGH PRESSURE SHIFTS EAST OF THE REGION TONIGHT...ALLOWING WAA TO
SPREAD ACROSS THE WESTERN CWA WHERE TEMPERATURES SHOULD BECOME
STEADY OR SLOWLY RISE AFTER MIDNIGHT. ANOTHER WEAK LOW PRESSURE
SYSTEM PASSING ACROSS THE REGION ON FRIDAY WILL BRING WARM
TEMPERATURES BACK INTO THE AREA. TEMPS AT 925/850 MB ARE PROJECTED
TO RANGE AROUND NORMAL...WHICH WHEN COMBINED WITH DECENT MIXING
WINDS SHOULD EQUAL HIGHS IN THE MID 30S...TO THE MID 40S. WOULD
NOT BE TOO SURPRISED IF HIGH TEMPERATURES END UP BEING WARMER.
SLIGHTLY COOLER LOW LEVEL TEMPERATURES ALONG WITH WEAK CAA ON
SATURDAY WILL RESULT IN HIGHS IN THE LOW TO MID 30S.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
LATEST MODEL RUNS CONTINUE TO FORECAST A MAJOR PATTERN SHIFT
DURING THE LONG TERM. HOWEVER THE DETAILS REMAIN SKETCHY AS EACH
MODEL HAS ITS OWN IDEA ON HOW TO HANDLE ENERGY WITHIN THE
DEVELOPING MID LEVEL TROF AND THAT TROFS EVOLUTION THROUGH THE
MIDDLE OF NEXT WEEK. THE ECMWF IS BY FAR THE MOST AGGRESSIVE IN
SETTING UP A BAROCLINIC ZONE ACROSS THE REGION AND CRANKS OUT
COPIOUS AMOUNTS OF PCPN FROM TUESDAY THROUGH THURSDAY. THE GFS IS
MORE PROGRESSIVE AND FEATURES A MORE POSITIVE TILT MID LEVEL TROF
OVER THE WESTERN/CENTRAL CONUS LEADING TO A LESS INTENSE
BAROCLINIC ZONE OVER THE NORTHERN PLAINS. THE LAST COUPLE RUNS OF
THE ECMWF HAVE BEEN CONSISTENTLY SLOWER AND WETTER VS THE GFS. BUT
IT SEEMS OVERLY WET. NONETHELESS WILL BE AN INTERESTING MIDDLE OF
NEXT WEEK WEATHER-WISE WITH A MIXED BAG OF PCPN EXPECTED NO MATTER
WHICH MODEL YOU LIKE. TEMPERATURES ARE EXPECTED TO BE ABOVE NORMAL
FOR THE FIRST PART OF THE PERIOD...BUT THEN TRANSITION TOWARD
NORMAL AS COLDER AIR INVADES FROM CANADA TOWARD MID TO LATE WEEK.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
MVFR CIGS WILL PREVAIL THIS AFTERNOON AND INTO THE OVERNIGHT
HOURS ACROSS THE WESTERN HALF OF THE CWA...INCLUDING KPIR AND
KMBG. KABR AND KATY LOOK TO BE RIGHT ON THE EDGE OF THESE
CIGS...SO WILL BE IN AND OUT OF THE MVFR CIGS. FROM LATE TONIGHT
AND THROUGH THE MORNING HOURS ON FRIDAY...VFR CONDITIONS WILL
PREVAIL.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...SERR
SHORT TERM...SD
LONG TERM...TDK
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1035 AM CST THU NOV 28 2013
.UPDATE...
THE MAIN FORECAST CHANGES THIS MORNING REVOLVE AROUND THE STRATUS
DECK THAT HAS SPREAD OVER THE REGION. MODELS ARE MUCH TO
OPTIMISTIC IN ERODING THE CLOUD DECK...SO ADJUSTED THE SKY GRIDS TO
KEEP THE WESTERN HALF OF THE CWA UNDER CLOUD COVER MUCH LONGER
THAN ORIGINALLY ANTICIPATED. ALSO EXTENDED THE FLURRIES MENTION
AS SEVERAL OBS HAVE REPORTED VERY LIGHT SNOW THIS MORNING. OVERALL
THE OTHER FORECAST FIELDS SEEM TO BE ON TRACK...TEMPERATURES WILL
REMAIN PRETTY STEADY THROUGH THE DAY...AND THE INHERITED FORECAST
TREND SEEMS TO BE REFLECTING THIS WELL.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
AN EXTENSIVE STRATUS DECK OVER THE REGION IS KEEPING TEMPERATURES
RELATIVELY MILD WITH CURRENT READINGS IN THE MID 20S. BASED ON THE
PAST FEW RUNS OF THE RUC...IT SEEMS UNLIKELY THIS STRATUS DECK
WILL DISSIPATE ANYTIME SOON. WOULD NOT BE TOO SURPRISED IF THESE
CLOUDS HANG AROUND THROUGH THIS AFTERNOON BEFORE DRIER AIR AT 925
MB MOVES IN FROM THE SOUTHWEST. OF COURSE THESE CLOUDS WILL MAKE
FORECASTING HIGH TEMPERATURES RATHER DIFFICULT. HAVE RELIED UPON
THE RUC MODEL WHICH SHOWS A SLIGHT COOL DOWN AROUND SUNRISE...THEN
A SLIGHT INCREASE BY 21Z.
HIGH PRESSURE SHIFTS EAST OF THE REGION TONIGHT...ALLOWING WAA TO
SPREAD ACROSS THE WESTERN CWA WHERE TEMPERATURES SHOULD BECOME
STEADY OR SLOWLY RISE AFTER MIDNIGHT. ANOTHER WEAK LOW PRESSURE
SYSTEM PASSING ACROSS THE REGION ON FRIDAY WILL BRING WARM
TEMPERATURES BACK INTO THE AREA. TEMPS AT 925/850 MB ARE PROJECTED
TO RANGE AROUND NORMAL...WHICH WHEN COMBINED WITH DECENT MIXING
WINDS SHOULD EQUAL HIGHS IN THE MID 30S...TO THE MID 40S. WOULD
NOT BE TOO SURPRISED IF HIGH TEMPERATURES END UP BEING WARMER.
SLIGHTLY COOLER LOW LEVEL TEMPERATURES ALONG WITH WEAK CAA ON
SATURDAY WILL RESULT IN HIGHS IN THE LOW TO MID 30S.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
LATEST MODEL RUNS CONTINUE TO FORECAST A MAJOR PATTERN SHIFT
DURING THE LONG TERM. HOWEVER THE DETAILS REMAIN SKETCHY AS EACH
MODEL HAS ITS OWN IDEA ON HOW TO HANDLE ENERGY WITHIN THE
DEVELOPING MID LEVEL TROF AND THAT TROFS EVOLUTION THROUGH THE
MIDDLE OF NEXT WEEK. THE ECMWF IS BY FAR THE MOST AGGRESSIVE IN
SETTING UP A BAROCLINIC ZONE ACROSS THE REGION AND CRANKS OUT
COPIOUS AMOUNTS OF PCPN FROM TUESDAY THROUGH THURSDAY. THE GFS IS
MORE PROGRESSIVE AND FEATURES A MORE POSITIVE TILT MID LEVEL TROF
OVER THE WESTERN/CENTRAL CONUS LEADING TO A LESS INTENSE
BAROCLINIC ZONE OVER THE NORTHERN PLAINS. THE LAST COUPLE RUNS OF
THE ECMWF HAVE BEEN CONSISTENTLY SLOWER AND WETTER VS THE GFS. BUT
IT SEEMS OVERLY WET. NONETHELESS WILL BE AN INTERESTING MIDDLE OF
NEXT WEEK WEATHER-WISE WITH A MIXED BAG OF PCPN EXPECTED NO MATTER
WHICH MODEL YOU LIKE. TEMPERATURES ARE EXPECTED TO BE ABOVE NORMAL
FOR THE FIRST PART OF THE PERIOD...BUT THEN TRANSITION TOWARD
NORMAL AS COLDER AIR INVADES FROM CANADA TOWARD MID TO LATE WEEK.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
MVFR CIGS ARE EXPECTED TO PERSIST AT LEAST INTO THE AFTERNOON FOR MOST
TERMINALS. MOST AREAS SHOULD BECOME VFR BY EVENING.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...SERR
SHORT TERM...SD
LONG TERM...TDK
AVIATION...TDK
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
325 PM CST THU NOV 28 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 325 PM CST THU NOV 28 2013
AT 3 PM...A LAKE INDUCED VORTICITY WAS LOCATED OVER THE APOSTLE
ISLANDS IN WESTERN LAKE SUPERIOR. MEANWHILE A SURFACE LOW WAS
LOCATED OVER EASTERN UPPER MICHIGAN. THIS LOW WAS PRODUCING WEAK
CYCLONIC FLOW ACROSS ACROSS WISCONSIN AND EAST CENTRAL MINNESOTA.
THIS CYCLONIC FLOW ALONG WITH STEEP 950-900 MB LAPSE RATES
/ASSOCIATED WITH A THERMAL TROUGH LOCATED FROM NORTHERN MINNESOTA
SOUTHEAST INTO EASTERN WISCONSIN/ IS HELPING MAINTAIN THESE
CLOUDS. THE 28.19Z RAP HAS A VERY GOOD HANDLE ON THESE CLOUDS AND
THEY SHOW THAT THEY WILL CONTINUE TO MOVE SOUTHEAST ACROSS MAINLY
OUR WISCONSIN COUNTIES AND THEN QUICKLY DISSIPATES THEM BETWEEN
28.01Z AND 28.03Z AS THE FLOW STARTS TO BECOME ANTICYCLONIC AND
THE 950-900 MB LAPSE RATES DECREASE.
FROM LATE TONIGHT INTO FRIDAY...THE 28.12Z MODELS CONTINUE TO
SHOW THAT WEAK WARM AIR ADVECTION WILL DEVELOP ABOVE 600 MB AS A
WEAK SHORT WAVE TROUGH APPROACHES THE REGION FROM THE CENTRAL
PLAINS. THIS WILL RESULT IN SOME MID TO HIGH CLOUDS ACROSS THE
AREA.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 325 PM CST THU NOV 28 2013
ON FRIDAY NIGHT...THE 28.12Z MODELS CONTINUE TO SHOW THAT A STRONG
SHORT WAVE TROUGH WILL MOVE SOUTHEAST ACROSS SOUTHWEST ONTARIO.
MUCH OF THE PV ADVECTION ASSOCIATED WITH THIS SYSTEM STAYS WILL
NORTH OF THE FORECAST AREA. THERE IS WEAK TO MODERATE 285 TO 300K
ISENTROPIC LIFT ACROSS NORTHERN AND EASTERN WISCONSIN. THIS LOWERS
THE CONDENSATION PRESSURE DEFICITS TO LESS 40 MB. MEANWHILE AT THE
285 AND 290K ISENTROPIC SURFACES YOU STILL NEED 100 TO 200 MB
OF LIFT FOR SATURATION. AS A RESULT...IT IS NOT LOOKING PROMISING
FOR ANY PRECIPITATION ACROSS TAYLOR AND NORTHERN CLARK COUNTY IN
NORTH CENTRAL WISCONSIN. HOWEVER WITH THE ECMWF...GEM...AND NAM
STILL INDICATING A POSSIBILITY. JUST KEPT A SLIGHT CHANCE /LESS
THAN 20 PERCENT/ ACROSS THIS AREA. BUFKIT SOUNDINGS CONTINUE TO
SHOW NO ICE...SO IF PRECIPITATION DOES INDEED OCCURS IT WOULD BE
IN THE FORM OF FREEZING DRIZZLE.
ON SATURDAY NIGHT...WEAK TO MODERATE WARM AIR ADVECTION AND STRONG
290 TO 300K ISENTROPIC LIFT DEVELOP ACROSS THE AREA AS A STRONG
SHORT WAVE TROUGH MOVES ACROSS THE REGION. THE 290-300K ISENTROPIC
CONDENSATION PRESSURE DEFICITS DROP TO LESS THAN 30 MB...SO WE
WILL LIKELY SEE CLOUDS WITH THIS WAVE. HOWEVER...THE 285K
CONDENSATION DEFICITS REMAIN IN THE 100 TO 200 MB RANGE...SO NOT
EXPECTING ANY PRECIPITATION WITH THIS WAVE.
FROM SUNDAY NIGHT INTO MONDAY...THE MODELS CONTINUE TO STRUGGLE
WITH THE TIMING OF A SHORT WAVE TROUGH COMING OUT AHEAD OF THE
DEVELOPING LONG WAVE TROUGH IN THE WESTERN UNITED STATE. BOTH THE
GEM AND ECMWF BRING A WAVE AHEAD OF THIS SYSTEM. MEANWHILE THE GFS
DOES NOT. AS AS RESULT...THE GEM AND ECMWF PRODUCES SOME LIGHT
PRECIPITATION ACROSS THE AREA. MEANWHILE THE GFS KEEPS THE AREA
DRY. SINCE THE MODELS HAVE BEEN CONSISTENT...JUST STAYED WITH THE
SLIGHT CHANCES THAT THE ALL BLEND PROVIDED.
FROM MONDAY NIGHT THROUGH THURSDAY...THE MODELS CONTINUE TO
STRUGGLE WITH THE EVOLUTION OF A LONG WAVE TROUGH OVER THE WESTERN
UNITED STATES. DUE TO THIS...THERE HAS BEEN A VARIETY OF DIFFERENT
LOW PRESSURE TRACKS FROM THE NORTHERN PLAINS EAST INTO THE GREAT
LAKES. THIS SYSTEM HAS THE POTENTIAL OF PRODUCING A WINTER STORM
SOMEWHERE ACROSS THE REGION...BUT WHERE IS VERY UNCERTAIN...SO
JUST STAYED WITH THE ALL BLEND FOR THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1130 AM CST THU NOV 28 2013
SKIES HAVE CLEARED OUT TO START THE TAF FORECAST. A LOW PRESSURE
TROUGH WAS SEEN UPSTREAM NEAR MSP...PRODUCING SOME MVFR TO VFR
STRATOCUMULUS AND EVEN A FEW FLURRIES. IF THIS TROUGH AND CLOUDS
HOLD TOGETHER...THEY WILL ARRIVE IN THE TAF SITES BETWEEN 20-22Z
AND HANG AROUND FOR A FEW HOURS. THINKING THE CEILINGS WILL RISE
AS THEY RUN INTO DRIER AIR AHEAD OF THEM...THUS HAVE MAINTAINED A
SCATTERED VFR CLOUD DECK THROUGH THE AFTERNOON. NEEDLESS TO SAY
SOMETHING TO WATCH DURING THE AFTERNOON HOURS. OTHERWISE...ANY OF
THIS STRATOCUMULUS SHOULD EITHER EXIT OR DISSIPATE AROUND THE TAF
SITES BY 01Z...WITH VFR CONDITIONS PERSISTING THROUGH FRIDAY
MORNING. NORTHWEST WINDS OF 10-15KT ARE EXPECTED TO DIMINISH THIS
EVENING WITH LOSS OF DAYTIME HEATING AND A RIDGE OF HIGH PRESSURE
MOVING IN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1032 AM MST THU NOV 28 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 332 AM MST THU NOV 28 2013
10Z SURFACE ANALYSIS SHOWS THE COLD FRONT BISECTING THE CWA FROM
NORTHWEST TO SOUTHEAST WITH LIGHT WINDS THROUGHOUT THE AREA. HIGH
CLOUDS ARE STREAMING OVERHEAD IN NORTHWEST FLOW WITH A STRATUS DECK
CREEPING SOUTH-SOUTHWESTWARD ACROSS THE CENTRAL PLAINS AND TOWARD
THE NORTHERN NEBRASKA PANHANDLE. CURRENT TRENDS COMBINED WITH NAM
BUFKIT SOUNDINGS AND RECENT HRRR RUNS SUGGEST THAT THIS STRATUS DECK
WILL IMPACT CHADRON AROUND SUNRISE AND MAY SNEAK INTO ALLIANCE AS
WELL THROUGH THE MORNING. GUIDANCE ALSO SUGGESTS THE LOW CLOUDS WILL
PERSIST THROUGH THE MORNING...AND WILL SCATTER OUT SLOWLY WITH
INCREASED SOLAR INSOLATION. IN ADDITION...SOUTHEASTERLY WINDS WILL
BECOME BREEZY ACROSS THE EASTERN PLAINS AS THE SFC HIGH SLIDES
SOUTH-SOUTHEAST ACROSS THE CENTRAL PLAINS. THIS WILL ADVECT SOME
LLVL MOISTURE INTO THE EASTERN PLAINS AND LIKELY CONTRIBUTE TO THE
SLOWER MIXING OUT OF THE STRATUS. INCREASED CLOUD COVER FOR TODAY IN
THIS AREA AS A RESULT...AND LOWERED MAX TEMPS A FEW DEGREES DUE TO THE
MORE PERSISTENT CLOUD DECK. OTHERWISE...EXPECTING A DRY...CALM
THANKSGIVING DAY WITH LIGHT WINDS AND CONTINUAL HIGH CIRRUS MOVING
OVERHEAD FROM THE NORTHWEST.
TONIGHT...A SHORTWAVE WILL MOVE EASTWARD ACROSS CENTRAL CANADA WHILE
A SECOND WEAK WAVE WILL MOVE ACROSS COLORADO. THE COMBINATION OF
FEATURES WILL DEEPEN THE LEESIDE SFC PRESSURE TROUGH...ALTHOUGH THE
DEEPEST PRESSURE FALLS WILL REMAIN WELL REMOVED FROM THE REGION AND
THEREFORE THE SFC PRESSURE GRADIENT WILL NOT BECOME VERY STRONG.
STILL LOOKING AT 850/700 MB CAG-CPR GRADIENTS OF 30 DAM OR LESS BY
EARLY FRIDAY MORNING. A LOOK AT A CROSS SECTION OF LAPSE RATES AND
WINDS THROUGH THE WIND PRONE REGIONS ALONG AND WEST OF THE LARAMIE
RANGE SHOWS THE INCREASE IN WINDS WITH THE STRENGTHENING
GRADIENT...BUT THE INVERSION REMAINS NEAR THE GROUND EARLY FRIDAY
MORNING WHICH SHOULD MINIMIZE GAP EFFECTS. THE INVERSION WILL LIFT
JUST OFF THE SURFACE AND WILL REMAIN RELATIVELY WEAK THROUGH
FRIDAY...BUT SHOULD BE STRONG ENOUGH TO PRODUCE MODERATE
GRADIENT/GAP WINDS THROUGH FRIDAY NIGHT. LOOKING AT SUSTAINED
WEST-SOUTHWEST WINDS IN THIS AREA ON AVERAGE OF 25 TO 35 MPH WITH A
FEW PERIODS OF STRONGER WINDS IN THE MORNING HOURS AS THE INVERSION
BEGINS TO LIFT. GUSTS SHOULD REMAIN WITHIN THE 50 TO 55 MPH ZONE AS
WINDS JUST OFF THE SURFACE ARE PROGGED TO ONLY BE AS HIGH AS 40 KTS.
LASTLY FOR FRIDAY...LITTLE CHANGE TO THE AIRMASS OUT IN THE FAR
WESTERN PORTIONS OF THE FORECAST AREA ON FRIDAY MORNING SUGGESTS A
RETURN OF STRATUS AND PATCHY FOG IN FAR SOUTHWESTERN CARBON COUNTY.
WITH LITTLE CHANGE IN THE SYNOPTIC PATTERN ON SATURDAY...EXPECT
MODERATE WINDS TO CONTINUE THROUGH AT LEAST SATURDAY AFTERNOON. BREEZY
WEST-NORTHWEST WINDS WILL EXPAND WESTWARD AND JUST TO THE LEE OF THE
MOUNTAINS DURING THE AFTERNOON HOURS AS THE INVERSION LIFTS...WHICH
WILL WARM TEMPS ACROSS THE EASTERN PLAINS BACK INTO THE 50S FOR
FRIDAY AND SATURDAY DUE TO DOWNSLOPE WARMING EFFECTS. A WEAK
SHORTWAVE MOVING TOWARD THE REGION ON SATURDAY AFTERNOON WILL BRING
WITH IT A PLUME OF LOW-MID LEVEL MOISTURE. COULD SEE A FEW
OROGRAPHIC SNOW SHOWERS OVER THE MOUNTAINS IN THE LATE AFTERNOON AS
THIS WEAK ENERGY AND MOISTURE MOVE OVERHEAD.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 332 AM MST THU NOV 28 2013
VERY DEFINITE PATTERN CHANGE CONTINUES TO BE ADVERTISED IN THE
LONG TERM. LOOKS VERY COLD AND WET FOR NEXT WEEK.
STARTING OFF SATURDAY NIGHT...LOOKS LIKE OUR WIND PRONE AREAS WILL
BE WINDY AS GFS 700MB WINDS ARE UP AROUND 45KTS SATURDAY NIGHT.
AFTER A DECREASE IN WINDS DURING THE DAY SUNDAY...THEY PICK UP
AGAIN SUNDAY NIGHT...THOUGH NOT AS STRONG AS PREVIOUS MODEL RUNS
WERE ADVERTISING. RIGHT NOW...THE NEW GFS WINDS ARE RIGHT AROUND
45-50KTS SUNDAY EVENING INTO MONDAY. CRAIG TO CASPER 700MB HEIGHT
GRADIENT STILL TIGHT THOUGH...RIGHT AROUND 70MTRS...SO IF THIS
HOLDS TRUE...WE WILL PROBABLY NEED SOME WIND HEADLINES FOR THIS
TIME FRAME.
MODELS STILL ADVERTISING A DRASTIC CHANGE IN THE WEATHER TUESDAY
AS A STRONG PACIFIC LOW PRESSURE SYSTEM MOVES INTO THE PACNW.
FRONT DOES NOT MAKE IT INTO SOUTHEAST WYOMING UNTIL WEDNESDAY
MORNING. MODELS CONTINUE TO SHOW THIS FRONT STALLING OVER NORTHERN
COLORADO AND PERSISTING THROUGH THE REMAINDER OF THE WEEK. 700MB
TEMPERATURES ARE QUITE COLD BEHIND THE FRONT. GFS SHOWING -18 TO
-20C WHILE NEW ECMWF RUN SHOWING -16 TO -18C. GOING TO BE QUITE
COLD THROUGH THE REMAINDER OF THE WEEK. HIGHS THURSDAY/FRIDAY MAY
ONLY BE IN THE TEENS WITH LOWS CLOSE TO ZERO AT MANY LOCATIONS.
&&
.AVIATION...(FOR THE 18Z TAFS)
STRATUS ACROSS SOUTH DAKOTA AND CENTRAL/EASTERN NEBRASKA IS NOT
EXPECTED TO MOVE INTO THE NORTHERN NE PANHANDLE THIS
AFTERNOON...ALTHOUGH IT IS CLOSE TO KCDR AT THIS HOUR. WILL CONTINUE
TO MONITOR THE WESTWARD PROGRESSION OF THIS LOW CIG STRATUS.
OTHERWISE...LIGHT WINDS AND VFR CONDITIONS WILL CONTINUE ACROSS
SOUTHEAST WYOMING AND WESTERN NEBRASKA THROUGH TONIGHT.
&&
.FIRE WEATHER...
ISSUED AT 332 AM MST THU NOV 28 2013
NO FIRE WEATHER CONCERNS ANTICIPATED THROUGH THE NEAR TERM. MILD AND
DRY CONDITIONS WILL CONTINUE ACROSS THE DISTRICT OVER THE NEXT FEW
DAYS WITH DAYTIME TEMPS AVERAGING IN THE 40S AND 50S DEGREES...WITH
COOLER READINGS OVER THE HIGHER TERRAIN. MINIMUM HUMIDITIES WILL BE
AT OR ABOVE 30 PERCENT EACH AFTERNOON. MODERATE WINDS ARE EXPECTED
ON FRIDAY AND SATURDAY IN THE WIND PRONE REGIONS ALONG AND WEST OF
THE LARAMIE RANGE WITH SUSTAINED SPEEDS BETWEEN 25 AND 40 MPH AND
GUSTS AROUND 50 MPH AT TIMES. A STRONG WEATHER SYSTEM WILL BEGIN TO
TAKE SHAPE LATE THIS WEEKEND INTO THE EARLY PART OF NEXT
WEEK...LIKELY BRINGING STRONGER WINDS...COLDER TEMPERATURES AND AN
INCREASED CHANCE FOR ACCUMULATING SNOWS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RJM
LONG TERM...CLAYCOMB
AVIATION...TJT
FIRE WEATHER...RJM