Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/05/13
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
850 PM MST WED DEC 4 2013
...FREEZING TEMPERATURES FOR THE SOUTHWEST AND SOUTH-CENTRAL
ARIZONA DESERTS EARLY FRIDAY MORNING...
&&
.SYNOPSIS...
A LARGE AND VERY COLD LOW PRESSURE SYSTEM WILL CONTINUE TO IMPACT
THE REGION THE REMAINDER OF THE WEEK. THIS WEATHER SYSTEM WILL STILL
BRING A CHANCE FOR LIGHT RAIN AND MOUNTAIN SNOW ACROSS SOUTHEAST
ARIZONA THROUGH THURSDAY MORNING...AND MUCH COOLER TEMPERATURES TO
THE DESERT SOUTHWEST INTO THE UPCOMING WEEKEND.
&&
.DISCUSSION...
THE LARGE UPPER LEVEL TROUGH ACROSS THE WESTERN UNITED STATES MADE
ITS WAY INTO SOUTHERN ARIZONA EARLIER TODAY BRINGING MUCH COOLER
TEMPERATURES AND SOME SCATTERED LIGHT SHOWERS TO SOUTH-CENTRAL AND
EASTERN ARIZONA. CURRENTLY ACROSS THE CWA...STILL SEE SOME RADAR
RETURNS ACROSS EASTERN PINAL INTO SOUTHERN GILA COUNTY. THIS AREA OF
SHOWERS SHOULD CONTINUE TO AROUND MIDNIGHT...BUT LATEST HRRR RUNS
SHOW THIS ACTIVITY PUSHING JUST TO THE EAST OF SOUTHERN GILA COUNTY
SHORTLY AFTER MIDNIGHT. HAVE TRIMMED BACK ON POPS QUITE A BIT ACROSS
THE LOWER DESERTS...BASICALLY GOING BELOW 10 PERCENT...WHILE KEEPING
HIGH CHANCE POPS IN FOR MUCH OF SOUTHERN GILA COUNTY FOR THE REST OF
THE EVENING. SNOW LEVELS REMAIN AROUND 6000 FT...SO ONLY THE HIGHEST
PEAKS SHOULD PICK UP ANY ACCUMULATING SNOWS. ACROSS THE LOWER
DESERTS...TEMPERATURES WILL FALL INTO THE 30S AND 40S OVERNIGHT WITH
THE COLDEST TEMPERATURES ACROSS PORTIONS OF SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA WHERE SKIES ARE EXPECTED TO BECOME MOSTLY CLEAR
TONIGHT. FREEZE WARNING IS IN EFFECT FOR JTNP TONIGHT...WITH OTHER
FREEZE WARNINGS ACROSS SOUTHWEST AND SOUTH-CENTRAL ARIZONA FOR
THURSDAY NIGHT/FRIDAY MORNING. THE COLDEST AIR OF THIS SYSTEM HAS
NOT QUITE MADE IT HERE...BUT AS A SECOND SHORTWAVE TROUGH DIGS
ACROSS THE AREA THURSDAY MORNING...850MB TEMPERATURES FALL TO AROUND
ZERO OR JUST BELOW ZERO CELSIUS. THIS COLD AIR MASS WILL STICK
AROUND AT LEAST THROUGH EARLY NEXT WEEK.
&&
.PREVIOUS DISCUSSION...
TONIGHT THROUGH FRIDAY...
RADAR/IR SATELLITE IMAGERY REVEAL THAT MOST OF THE LIGHT RAIN
SHOWERS HAVE MOVED EAST OF PHOENIX...AND SURFACE OBSERVATIONS SHOW
THAT THE FRONT CONTINUES ITS TREK INTO WESTERN NM AND SOUTHEAST
ARIZONA. MODELS STILL HAVE THE SURFACE FRONT STALLING/SLOWING DOWN
OVER FAR SOUTHEAST PORTIONS OF THE STATE...SO PRECIPITATION CHANCES
WILL SLOWLY DROP OFF AND LINGER OVER OUR EASTERN ZONES NEAR GLOBE
AND HILLTOP THROUGH THURSDAY AFTERNOON. TEMPERATURE-WISE...WE
REACHED FORECAST HIGHS EARLIER TODAY AT MANY DESERT LOCATIONS...WITH
PHOENIX HITTING 63 DEGREES AROUND 0930 HOURS THIS MORNING. A
SIGNIFICANTLY COLDER AIRMASS WILL CONTINUE TO OVERSPREAD THE REGION
BEHIND THE DEPARTING FRONT...AND SNOW LEVELS PLUMMET TONIGHT AS THE
COLD AIR RUSHES IN. SNOW ACCUMULATIONS THROUGH THURSDAY MORNING
WILL BE CONFINED TO ELEVATIONS ABOVE 5000 FEET WITH ONE HALF TO ONE
INCH OF SNOW POSSIBLE. THE COLDER AIR WILL ALSO DROP OVERNIGHT
TEMPERATURES ACROSS THE HIGHER ELEVATION SITES ACROSS SOUTHEAST
CALIFORNIA...AND AS SUCH A FREEZE WARNING REMAINS IN EFFECT TONIGHT
THROUGH THURSDAY FOR JOSHUA TREE NATIONAL PARK. THE COLD AIR MASS
WILL REMAIN IN PLACE ACROSS THE REGION FOR THE REST OF THE
WEEK...AND WILL BE REINFORCED BY YET ANOTHER SHORT WAVE DUE TO
ROTATE SOUTH THROUGH THE GREAT BASIN AND BROADEN THE TROUGH ACROSS
THE WESTERN CONUS ON SATURDAY. UNTIL THEN...DAYTIME TEMPERATURES
WILL REMAIN WELL BELOW NORMAL...IN THE LOW TO MID 50S FOR THE
DESERTS.
A MORE SIGNIFICANT IMPACT WILL BE THE COLDER FREEZING TEMPERATURES
THAT CAN BE EXPECTED BY EARLY FRIDAY MORNING ACROSS THE SOUTH
CENTRAL DESERTS STRETCHING EAST INTO THE HIGHER TERRAIN OF SOUTHERN
GILA COUNTY NEAR GLOBE. WARMER LOCATIONS IN AND AROUND THE GREATER
PHOENIX AREA MIGHT NOT DIP BELOW 32 DEGREES...BUT MANY OTHER REMOTE
OR SHELTERED DESERT LOCATIONS SURROUNDING THE METROPOLITAN AREA
IN MARICOPA AND PINAL COUNTIES...AND EXTENDING WEST INTO YUMA AND LA
PAZ COUNTIES...WILL DIP BELOW FREEZING FRIDAY MORNING.
SATURDAY INTO TUESDAY...
ANOTHER LOW PRESSURE SYSTEM WILL MOVE THROUGH THE REGION SATURDAY.
THIS ONE TRACKS FURTHER SOUTH AND WILL HAVE LOWER SNOW LEVELS. THE
CONTINENTAL TRAJECTORY OF THE LOW WILL ALSO CUT OFF ANY RICH
MOISTURE TAP FROM LOWER LATITUDES. BUT THE MOISTURE WILL BE
SUFFICIENT GIVEN THE BETTER PRECIPITATION EFFICIENCY DUE TO THE
COLDER AIR INVOLVED. THE PRECIPITATION WILL COME MAINLY WITH THE
FRONTAL ZONE AS THE LOW SWINGS THROUGH THE AREA...SO POPS INCREASE
FROM WEST TO EAST DURING THE DAY SATURDAY AND CONTINUE OVERNIGHT
BEFORE TAPERING OFF FROM WEST TO EAST SUNDAY. THE BEST OPPORTUNITY
FOR POPS OVER OUR AREA APPEARS TO BE SATURDAY NIGHT OVER SOUTH
CENTRAL ARIZONA. SNOW LEVELS BOTTOM OUT BETWEEN 2000-3000 FEET
SUNDAY...AND COULD PRODUCE SNOW AMOUNTS OF 5 TO 10 INCHES ABOVE 5000
FEET...WITH A SHARP DROP OFF AS ELEVATION DECREASES. THE SYSTEM
BEGINS MOVING EASTWARD MONDAY AS THE EASTERN PACIFIC RIDGE EXPANDS
INLAND ACROSS THE WESTERN STATES. TEMPS SATURDAY MORNING COULD BE
QUITE COLD...ESPECIALLY WHERE WINDS STAY LIGHT AND SKIES STAY CLEAR.
SUNDAY MORNING NOT EXPECTED TO BE AS COLD WITH CLOUD COVER AND
MIXING...BUT FREEZING TEMPS COULD ONCE AGAIN BE REALIZED MONDAY
MORNING WITH THE ARRIVAL OF MORE COLD AIR...CLEAR SKIES AND GOOD
RADIATIONAL COOLING.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA...AND KSDL...
EXPECT SOME LINGERING LOWER CLOUDS GENERALLY AROUND 8K FEET FOR THE
REST OF THE EVENING...AND POSSIBLY LASTING THROUGH THE OVERNIGHT
HOURS UP AGAINST THE HIGHER TERRAIN EAST OF PHOENIX. WESTERLY
GRADIENT WINDS SHOULD PREVAIL THROUGH THE ENTIRE NIGHT...BUT SOME
DRAINAGE EASTERLY WINDS MAY PUSH INTO THE KIWA AREA LATE TONIGHT.
THE DRAINAGE WINDS WILL LIKELY NOT FULLY TAKE OVER AT KPHX AND
KSDL...SO MAY JUST SEE A FEW HOUR PERIOD OF VARIABLE WINDS AROUND
SUNRISE BEFORE GOING BACK TO A WESTERLY COMPONENT BY LATE THURSDAY
MORNING.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA...INCLUDING KIPL AND
KBLH...
WILL SEE CLEARING SKIES OVERNIGHT WITH NORTH TO NORTHWEST WINDS UP
TO AROUND 10 KNOTS AT KBLH AND LIGHTER MORE WESTERLY WINDS AFFECTING
KIPL. NO AVIATION IMPACTS EXPECTED THROUGH THE TAF PERIOD.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
DECENT MODEL AGREEMENT SHOWING ANOTHER TROUGH MOVING THROUGH THE
AREA ON SATURDAY...WITH A CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW
SHOWERS SATURDAY INTO SUNDAY. A COUPLE INCHES OF SNOW MAY ACCUMULATE
AT ELEVATIONS ABOVE 3000 FT. OTHERWISE...MAINLY DRY BUT UNUSUALLY
COLD CONDITIONS WILL PREVAIL OVER THE WEEKEND AND EARLY NEXT WEEK.
MUCH OF THE AREA WILL SEE OVERNIGHT LOW TEMPERATURES COME CLOSE OR
FALL BELOW THE FREEZING MARK. HUMIDITY VALUES WILL REMAIN QUITE
ELEVATED THROUGH THE PERIOD WITH MINIMUM HUMIDITIES MOSTLY BETWEEN
20 AND 30 PERCENT...AND GOOD TO EXCELLENT OVERNIGHT RECOVERY. WINDS
WILL GENERALLY BE LIGHT WITH SOME OCCASIONAL AFTERNOON UPSLOPE
GUSTINESS...AND DIRECTIONS FAVORING BETWEEN WEST AND NORTH.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...FREEZE WARNING IN EFFECT FOR THURSDAY NIGHT THROUGH FRIDAY
MORNING FOR AZZ021>024-026>028.
CA...FREEZE WARNING IN EFFECT FOR TONIGHT THROUGH THURSDAY MORNING
FOR CAZ030.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...KUHLMAN
PREVIOUS DISCUSSION...MEYERS/AJ
AVIATION...KUHLMAN
FIRE WEATHER...LEINS
AREA FORECAST DISCUSSION...UPDATED
NWS TUCSON AZ
550 PM MST WED DEC 4 2013
.UPDATE...THE WIND ADVISORY PREVIOUSLY IN EFFECT FOR MOST LOCALES
EAST AND SOUTH OF TUCSON HAS BEEN CANCELLED. GUSTY WINDS ARE
EXPECTED TO CONTINUE TONIGHT EAST AND SOUTH OF TUCSON. HOWEVER...
WIND SPEEDS WILL REMAIN BELOW WIND ADVISORY CRITERIA.
&&
.SYNOPSIS...A STRONG STORM SYSTEM MOVING THROUGH THE WESTERN
UNITED STATES WILL BRING A CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW
TO SOUTHEAST ARIZONA THROUGH THURSDAY. THIS SYSTEM WILL ALSO BRING
IN MUCH COOLER TEMPERATURES...WITH WIDESPREAD FREEZING TEMPERATURES
ACROSS ALL OF SOUTHEAST ARIZONA FRIDAY MORNING. ANOTHER STORM SYSTEM
WILL BRING GUSTY WINDS...A CHANCE OF THE PRECIPITATION AND A
REINFORCEMENT OF COLDER AIR LATE THIS WEEKEND.
&&
.DISCUSSION...THE UPPER PATTERN IS DEFINED BY A HIGH AMPLITUDE UPPER
RIDGE IN THE EASTERN PACIFIC...AND A LONGWAVE TROUGH ACROSS THE
WESTERN STATES. SHORTWAVE ENERGY MOVING SOUTH ALONG THE CALIFORNIA
COAST WILL ROTATE INTO THE SOUTHERN EDGE OF THIS TROUGH BEFORE IT
TRACKS ACROSS THE AREA TONIGHT AND THURSDAY. THE TIGHT GRADIENT OUT
AHEAD OF THIS TROUGH HAS RESULTED IN BREEZY TO WINDY CONDITIONS...
ESPECIALLY TO THE EAST AND SOUTH OF TUCSON. SURFACE OBSERVATIONS IN
KDUG INDICATE SUSTAINED WINDS IN THE 25 TO 30 MPH RANGE WITH GUSTS
TO 45 MPH. A WIND ADVISORY IS IN EFFECT TO THE EAST UNTIL 8 PM MST
THIS EVENING. THE LATEST MODEL GUIDANCE STILL INDICATES 45 KT FLOW
ACROSS COCHISE AT 06Z TONIGHT. THIS USUALLY MEANS THAT LOCALIZED
AREAS NEAR THE HUACHUCA MOUNTAINS WILL CONTINUE TO EXPERIENCE STRONG
AND GUSTY WINDS WELL INTO THE OVERNIGHT HOURS.
ACCORDING TO THE LATEST SURFACE OBSERVATIONS...THE SOUTHERN TIP OF
THE SURFACE COLD FRONT ASSOCIATED WITH THIS SYSTEM IS CURRENTLY
POSITIONED ACROSS CENTRAL PIMA COUNTY EXTENDING INTO NW PINAL
COUNTY. AT 230 PM MST...KEMX RADAR JUST BEGINNING TO INDICATE SHOWERS
DEVELOPING ACROSS THE TOHONO OODHAM NATION. THE HRRR AND UNIVERSITY
OF ARIZONA WRF MODELS INDICATE THAT THE COLD FRONT WILL PUSH WEST
INTO TUCSON BY 5 PM THIS AFTERNOON WITH PCPN BEGINNING TO EXPAND AND
ENHANCE AS IT MOVES FARTHER EAST. EXPECT SHOWERS TO BECOME MORE
NUMEROUS THIS EVENING WITH THE MAJORITY OF THE PCPN AFFECTING THE
CWA OVERNIGHT INTO THURSDAY MORNING. MOISTURE SOMEWHAT LIMITED WITH
THIS SYSTEM AND STILL EXPECT ONLY A TENTH TO A THIRD INCH WITH MAYBE
A HALF INCH IN THE MOUNTAINS. THIS TRANSLATES INTO SNOWFALL AMOUNTS
JUST BELOW ADVISORY CRITERIA. IT IS POSSIBLE THAT SOME OF THE
HIGHEST PEAKS MAY BARELY HIT LOW END SNOW ADVISORY CRITERIA...BUT IT
WILL NOT BE WIDESPREAD ENOUGH TO WARRANT AN ADVISORY.
THE MAIN ISSUE WITH THIS SYSTEM IS NOT THE WIND OR THE PCPN...BUT
THE TEMPERATURES. COLD AIRMASS MAKING ITS WAY SOUTH WILL BRING THE
FIRST WIDESPREAD FREEZING TEMPERATURES TO THE LOWER DESERTS FROM
TUCSON WEST. HAVE DECIDED TO ISSUE A FREEZE WARNING FOR FRIDAY
MORNING TO GET THE WORD OUT TO PROTECT PEOPLE...PETS...PIPES AND
PLANTS.
ANOTHER STRONG WEATHER SYSTEM WILL MAKE ITS WAY SOUTH INTO ARIZONA
THIS WEEKEND. THE ECMWF IS MUCH COLDER AND THUS MORE AGGRESSIVE THAN
THE GFS BRINGING PCPN AND ANOMALOUSLY COLDER TEMPS. INCREASED POPS AND
LOWERED TEMPS SAT NIGHT INTO MONDAY TO REFLECT THIS TREND.
&&
.AVIATION...VALID THRU 06/00Z.
UPPER LEVEL JET MOVING ACROSS SOUTHEAST ARIZONA AND INTO NEW MEXICO
BY THURSDAY NOON. ASSOCIATED WITH THIS CHANGE...COLD AIR WILL ADVECT
INTO SOUTHERN ARIZONA TONIGHT AND THURSDAY. STRONG SURFACE WINDS OF
20-25 KT WITH GUSTS UP TO 45 KTS SUBSIDING AROUND 05/06Z. FROM
05/00Z INTO THURSDAY MIDDAY EXPECT ISOLD TO SCT -SHRA. PERIODS OF
MVFR CONDITIONS WILL BE PRESENT IN THE STRONGER SHOWERS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...LOW PRESSURE TROUGH OVER THE WEST IS EXPECTED TO
REMAIN THROUGH THE FIRST PART OF NEXT WEEK. THE STRONG WINDS
ASSOCIATED WITH THIS TROUGH WILL SUBSIDE AROUND MIDNIGHT AND MUCH
COLDER AIR WILL ADVECT INTO THE AREA THURSDAY. TEMPERATURES WILL
DROP ABOUT 15 DEGREES BELOW AVERAGE LATE THURSDAY AND CONTINUE
THROUGH THE WEEKEND. MOISTURE WITH THIS TROUGH IS LIMITED...ALTHOUGH
MANY AREAS WILL SEE LIGHT PRECIPITATION AMOUNTS. A SECOND STORM
SYSTEM WILL DROP INTO THIS TROUGH LATE SATURDAY FOR A CHANCE OF
VALLEY RAIN AND MOUNTAIN SHOWERS...ALONG WITH REINFORCING THE COLDER
TEMPERATURES INTO EARLY NEXT WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING FROM 10 PM THURSDAY TO 10 AM MST FRIDAY FOR
AZZ501>506.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
746 PM MST WED DEC 4 2013
.UPDATE...OTHER THAN A DISSIPATING BAND OF LIGHT SNOW OVER EASTERN
ELBERT AND NORTHERN LINCOLN COUNTIES...SNOW HAS ENDED. WILL DECREASE
POPS FOR TONIGHT.
BIGGEST CHALLENGE TONIGHT WILL BE HOW COLD IT WILL GET. AS THE DRIER
CONTINUES TO MOVE INTO THE AREA...CLOUDS WILL DECREASE. SKIES
ALREADY PARTLY CLOUDY NORTH OF INTERSTATE 76. THIS CLEARING WILL
ALLOW TEMPERATURE TO FALL WELL BELOW ZERO TONIGHT. CURRENT READINGS
WHERE THE SKIES HAVE CLEARED SOME ARE ZERO TO 5 BELOW...SINGLE
DIGITS HOLDING ON UNDER THE CLOUD COVER. LOWERED TEMPERATURES A
DUE TO THE EARLIER CLEARING SKIES. ALSO THE RAP AND HRRR ARE
SHOWING TEMPERATURES -10 TO -15 OVER NORTHERN PARTS OF THE AREA.
COLDEST SPOTS WILL BE ALONG THE WYOMING BORDER WHERE THE BEST
CLEARING WILL OCCUR AND THE COLDEST AIR IS. PARTS OF JACKSON COUNTY
MAY APPROACH -30 OVERNIGHT.
RECORD LOW FOR DECEMBER 4TH IS -5 WHICH WE WE WILL LIKELY BREAK
BEFORE MIDNIGHT AS THE CURRENT TEMPERATURE IS -4. THE RECORD LOW FOR
DECEMBER 5TH IS -15 WHICH WILL BE TOUGH TO REACH OVERNIGHT BUT NOT
IMPOSSIBLE. COULD SEE SOME SHALLOW FOG TOWARDS DAY BREAK IN THE LOW
LYING AREAS...DON`T THINK IT WILL BE WIDESPREAD OR CONFIDENT ENOUGH
THAT IT WILL OCCUR TO PUT IN THE FORECAST.
&&
.AVIATION...SNOW HAS ENDED AND CLOUDS WILL DECREASE THROUGH THE
EVENING HOURS WITH JUST SCATTERED MID CLOUDS EXPECTED AFTER 06Z.
LIGHT WINDS WILL PREVAIL OVERNIGHT. SHALLOW FOG WILL BE POSSIBLE IN
LOW LYING AREAS AFTER MIDNIGHT...DON`T THINK IT WILL AFFECT THE
AIRPORTS BUT WILL HAVE A VCFG IN FOR KDEN. MID CLOUDS WILL INCREASE
THURSDAY AFTERNOON WITH CEILINGS OF 3000 TO 6000 FEET POSSIBLE.
&&
.PREV DISCUSSION... /ISSUED 340 PM MST WED DEC 4 2013/
SHORT TERM...JET DYNAMICS HAS MOVED INTO SOUTHERN COLORADO WITH
SUBSIDENCE AND SLIGHTLY DRIER AIR WORKING SOUTH ACROSS CFWA. STILL
ENOUGH MOISTURE AND WEAK LIFT ALONG WITH OROGRAPHICS KEEPING SOME
LIGHT SNOW GOING ACROSS THE MOUNTAINS...WHICH SHOULD PERSIST INTO
THE EVENING BEFORE DECREASING. WITH SUBSIDENCE AN LACK OF
DYNAMICS...ANY ADDITIONAL ACCUMULATION TO BE LESS THAN 3 INCHES.
SOME LIGHT SNOW ALSO OCCURRING ACROSS THE MOUNTAIN VALLEYS AND
FOOTHILLS AS WELL AS PORTIONS OF THE PLAINS MAINLY SOUTH OF
INTERSTATE 70. STILL SOME CHANCE FOR LIGHT SNOW THIS
EVENING...MAINLY SOUTHERN FOOTHILLS AND PALMER DIVIDE. SUBSIDENCE
AND DRIER AIR WILL LIMIT ANY ACCUMULATION. WILL CANCEL ALL
HILITES WITH THIS UPDATE. SOME CLEARING EXPECTED TONIGHT FROM
NORTH TO SOUTH...THOUGH FAIRLY EXTENSIVE CLOUD COVER MAY PERSIST
ACROSS THE SOUTHERN PORTION OF THE CFWA AS NEXT DISTURBANCE INTO
SOUTHWEST COLORADO. EXTENT OF CLOUD COVER WILL INDEED AFFECT HOW
TEMPERATURES PLUMMET. LOWERED MINS A FEW DEGREES...ESPECIALLY NEAR
THE WYOMING BORDER AND ACROSS NORTH AND MIDDLE PARKS WHERE LESS
CLOUD IS EXPECTED. ON THURSDAY...FLOW ALOFT BECOMES SOUTHWEST WITH
SOME MID LEVEL QG ASCENT SPREADING INTO THE SOUTHERN SECTIONS OF
THE CFWA. WITH INCREASING CLOUD COVER...SOME SNOW WILL BE POSSIBLE
OVER THE MOUNTAINS AND FOOTHILLS BY...MAINLY SOUTH OF INTERSTATE
70. ANY ACCUMULATIONS WILL BE LIGHT AND LESS THAN 2 INCHES. ACROSS
THE PLAINS...THERE COULD BE A SLIGHT CHANCE OF SNOW THOUGH THIS
LOOKS CONFINED TO AREAS SOUTH OF DENVER. ANY ACCUMULATIONS SHOULD
BE CONFINED TO THE PALMER DIVIDE...LESS THAN ONE HALF INCH.
TEMPERATURES TO WARM BACK INTO THE SINGLE DIGITS...STRUGGLING TO
GET NEAR 10 DEGREES. LOOKS LIKE GUIDANCE IS A BIT TOO WARM.
LONG TERM...MODELS HAVE AN UPPER TROUGH AXIS MOVE ACROSS COLORADO
THURSDAY NIGHT INTO FRIDAY MORNING. ON FRIDAY...STRONG WEST-
SOUTHWESTERLY FLOW ALOFT IS PROGGED. IT BECOMES SOUTHWESTERLY
FRIDAY NIGHT AND SATURDAY BUT STAYS PRETTY STRONG. THE NEXT UPPER
TROUGH`S AXIS IS PROGGED TO BE OVER THE WESTERN COLORADO BORDER AT
12Z SUNDAY MORNING. THE QG VERTICAL VELOCITY FIELDS HAVE WEAK
UPWARD SYNOPTIC SCALE MOTION FOR THE CWA THURSDAY NIGHT...THEN
DOWNWARD MOTION FRIDAY AND FRIDAY NIGHT...WEAK UPWARD MOTION
RETURNS...AND IT GETS STRONGER BY MID DAY SATURDAY AND SATURDAY
NIGHT. THE BOUNDARY LAYER FLOW IS PROGGED TO BE EASTERLY THURSDAY
NIGHT...THEN EAST-SOUTHEASTERLY ON FRIDAY. FOR FRIDAY NIGHT AND
SATURDAY...SOUTHEASTERLIES ARE PROGGED. FOR MOISTURE...THERE IS
SOME AROUND THURSDAY NIGHT THROUGH FRIDAY NIGHT...BUT NOTHING
GREAT. MOISTURE INCREASES ON SATURDAY. THERE IS A TAD OF
MEASURABLE SNOW FALL ON THE QPF FIELDS THURSDAY EVENING IN THE
FOOTHILLS AND PALMER RIDGE. THE QPF FIELDS SHOW NOTHING FOR THE
CWA THE REST OF THURSDAY NIGHT THROUGH FRIDAY. THERE IS A TAD
AGAIN FRIDAY NIGHT AND SATURDAY MORNING IN THE MOUNTAINS. THERE IS
A TAD INDICATED OVER MUCH OF THE CWA SATURDAY AFTERNOON...LESS
FOR SATURDAY NIGHT. FOR POPS...WILL GO WITH 10-30%S IN THE
MOUNTAINS...FOOTHILLS AND PALMER RIDGE THURSDAY EVENING. ON FRIDAY
AND FRIDAY NIGHT...SOME MINOR POPS FOR THE MOUNTAINS. WILL
INCREASE POPS IN ALL AREAS SATURDAY AND SATURDAY NIGHT....WITH
"CHANCE"S OVER THE PLAINS SATURDAY AFTERNOON AND NIGHT. WILL GO
WITH A FEW AREAS OF "LIKELY"S IN THE HIGH MOUNTAINS SATURDAY
NIGHT. NO HIGHLIGHTS RIGHT NOW. FOR TEMPERATURES...FRIDAY`S HIGHS
ARE 1-3 C WARMER THAN THURSDAY`S. SATURDAY`S HIGHS ARE 1-3 C
WARMER THAN FRIDAY`S. FOR THE LATER DAYS...SUNDAY THROUGH
WEDNESDAY...AN UPPER TROUGH IS PROGGED TO MOVE ACROSS COLORADO ON
SUNDAY...THEN ANOTHER WEAKER ONE ON MONDAY AFTERNOON AND EVENING.
THERE THE FLOW ALOFT IS NORTHWESTERLY TUESDAY INTO WEDNESDAY.
THERE MAYBE ANOTHER WEAK UPPER TROUGH TO MOVE ACROSS WEDNESDAY.
ANOTHER SURGE OF COLDER AIR PUSHES IN SUNDAY MORNING...WITH
UPSLOPE BEHIND IT. MONDAY STAY`S COLD...BUT TUESDAY AND WEDNESDAY
WARM UP SOMEWHAT. WILL KEEPS POPS IN SUNDAY INTO MONDAY EVENING...
ESPECIALLY IN THE MOUNTAINS. FOR NOW TUESDAY AND WEDNESDAY LOOK
DRY...BUT WE`LL SEE.
AVIATION...LIGHT SNOW CONTINUES AT KBJC AND KAPA BUT HAS ENDED
AT KDEN. THE AREA OF LIGHT SNOW ACROSS THE DENVER AREA WILL BE ON
THE DECREASE THROUGH THE EVENING AND SHOULD END BY 03Z...WITH
CONDITIONS IMPROVING TO VFR. ANY ADDITIONAL ACCUMULATION TO BE
LESS THAN ONE HALF INCH...MAINLY AT KAPA. SKIES WILL GRADUALLY
CLEAR AFTER 06Z...WHICH WILL ALLOW TEMPERATURES TO DROP TO NEAR
-10. WINDS WILL DECREASE THROUGH THE EVENING WITH DRAINAGE
DEVELOPING. ON THURSDAY...SOME INCREASE IN MID AND HIGH LEVEL
MOISTURE FROM THE SOUTH BY THE AFTERNOON. LIGHT SNOW WILL BE
POSSIBLE ALONG THE PALMER DIVIDE...AND MAY REACH KAPA. AT THIS
TIME...THE ACTIVITY SHOULD STAY SOUTH OF THE AREA AIRPORTS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
UPDATE/AVIATION...MEIER
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
805 PM EST WED DEC 4 2013
.UPDATE (TONIGHT AND THURSDAY)...
01Z WATER VAPOR AND H4 RAP ANALYSIS SHOW A UPPER LEVEL PATTERN OVER
THE CONUS CHARACTERIZED BY LONGWAVE TROUGHING SPREADING EASTWARD
OVER THE CENTRAL PLAINS FROM THE INTER-MOUNTAIN WEST...AND
DOWNSTREAM RIDGING COVERING MUCH OF THE DEEP SOUTH AND EASTERN
SEABOARD. THIS RIDGE IS FIRMLY IN PLACE OVER THE EASTERN GULF OF
MEXICO AND FLORIDA PENINSULA...AND WILL ONLY AMPLIFY FURTHER DURING
THE NEXT 12-24 HOURS IN RESPONSE TO THE HEIGHT FALLS OVER THE
SOUTHERN PLAINS.
05/00Z KTBW SOUNDING PROFILE SHOWS SIGNS OF A SUBSIDENCE INVERSION
ASSOCIATED WITH THE UPPER RIDGE AROUND 750MB THIS EVENING...AND
WOULD EXPECT THIS FEATURE TO BECOME MORE PRONOUNCED IN FUTURE
SOUNDINGS AS THE SUPPRESSION ALOFT GROWS.
AT THE SURFACE...RIDGE OF HIGH PRESSURE CONTINUES TO NOSE BACK OVER
THE STATE AND EASTERN GULF OF MEXICO FROM THE WESTERN ATLANTIC. THE
GRADIENT RELAXED ENOUGH WEDNESDAY AFTERNOON IN ORDER TO ALLOW A
NOTICEABLE SEA-BREEZE CIRCULATION...AND EVEN A FEW SEA-BREEZE
SHOWERS TO THE SOUTH OF THE I-4 CORRIDOR. NUMERICAL GUIDANCE IN
DECENT AGREEMENT THAT THE GRADIENT WILL BE TIGHTER TOMORROW WITH
BOUNDARY LAYER FLOW BETWEEN 10-12 KNOTS OUT OF THE SOUTHEAST. THIS
FLOW...DESPITE THE POTENTIAL FOR EVEN HIGHER AFTERNOON
TEMPS...SHOULD BE ENOUGH TO SUPPRESS SEA-BREEZE FORMATION...OR AT
LEAST KEEP THE FRONT PINNED AT SHORE OR JUST OFFSHORE.
THE SCATTERED SHOWERS WE SAW LATE IN THE AFTERNOON HAS DECAYED WITH
THE LOSS OF DIURNAL HEATING AND ANTICIPATE A DRY OVERNIGHT FROM HERE
ON. WITH LESS SEA-BREEZE FORCING ON THURSDAY ALONG WITH GREATER
ATMOSPHERIC SUPPRESSION...DO NOT EXPECT TO SEE MUCH IN THE WAY OF
ADDITIONAL SHOWER ACTIVITY. LOCAL HIGH RESOLUTION AND NATIONAL
CONVECTION ALLOWING MODELS AGREE WITH THIS ASSESSMENT AND ARE
PRODUCING LITTLE IN THE WAY OF CONVECTION ON THURSDAY ACROSS THE
STATE. IT WILL HOWEVER BY A VERY WARM EARLY DECEMBER DAY. 850MB
TEMPS OF 14-15C ALONG WITH GOOD MIXING SHOULD ALLOW TEMPS TO CLIMB
INTO THE 80S...WITH MORE LOCATIONS SEEING MID 80S THAN WAS EVEN SEEN
ON WEDNESDAY.
THE REAL FORECAST CONCERN INTO THURSDAY MORNING WILL BE THE
POTENTIAL FOR SEA FOG IMPACTING PARTS OF OUR NORTHERN WATERS AND
NORTHERN NATURE COAST ZONES. THE SOUTHEAST FLOW WOULD TEND TO KEEP
THE FOG MAINLY OFFSHORE...BUT ONLY A SMALL DIFFERENCE IN WIND
DIRECTION COULD IMPACT PORTIONS OF CITRUS AND LEVY COUNTY. SPORT SST
ANALYSIS SHOWS WATER TEMPS IN THE LOWER/MID 60S ALONG THESE COUNTY
COASTS...AND DEWPOINTS ARE IN THE 70S...NOT THAT FAR OFFSHORE.
GUIDANCE SUCH AS THE NARRE AND RAP ARE QUITE AGGRESSIVE WITH THE SEA
FOG...BUT ALSO TEND TO BE BIASED ON THE AGGRESSIVE SIDE WITH FOG
EXTENT...ESPECIALLY TOWARD THE BEGINNING OF SEA FOG EVENTS. SO FOR
NOW...WILL KEEP THE MENTION OF AREAS OF FOG IN THE GRIDS AND MARINE
FORECAST...BUT WAIT AND SEE HOW THINGS DEVELOP OVERNIGHT BEFORE
CONSIDERING THE POTENTIAL FOR ANY LAND OR MARINE FOG ADVISORIES.
HAVE A GREAT REST OF YOUR EVENING!
&&
.AVIATION...
VFR CONDITIONS WITH SCT BUT OCNL BKN MID OR HIGH CLOUDS THROUGH THE
EVENING. PATCHY FOG LATE NIGHT WITH TEMPO MAINLY MVFR VSBY EXPECTED.
LIGHT SE WINDS BECOME SOUTHERLY MID-DAY THU.
&&
.MARINE...
LIGHT WINDS AND SEAS ARE EXPECTED THROUGH THE UPCOMING WEEKEND. MAIN
CONCERN WOULD BE THE POSSIBILITY OF SEA FOG OVERNIGHT INTO
THURSDAY...MAINLY FOR THE COASTAL WATERS FROM TARPON SPRINGS
NORTHWARD.
&&
PRELIMINARY POINT TEMPS/POPS...
TPA 67 83 67 83 / 10 0 10 10
FMY 65 85 66 84 / 10 0 10 0
GIF 64 83 64 83 / 10 10 10 0
SRQ 65 83 66 82 / 10 0 10 10
BKV 60 83 61 84 / 10 10 10 10
SPG 67 81 68 81 / 10 0 10 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS MIAMI FL
1227 PM EST TUE DEC 3 2013
.AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. LIGHT SOUTH TO
SOUTHEASTERLY WINDS WILL CONTINUE THIS AFTERNOON. THE SCT/BKN
STRATOCU CONTINUES TO HOLD ON AT 5-7KFT...SO KEPT IT IN FOR THE
AFTERNOON HOURS. MAINLY CLEAR SKIES ARE FORECAST FOR OVERNIGHT.
LIGHT AND VARIABLE WINDS TO A LIGHT LAND BREEZE FLOW IS EXPECTED
OVERNIGHT. SOUTHEAST WINDS ARE FORECAST TO INCREASE TO 5-10 KNOTS
BY LATE WEDNESDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 1026 AM EST TUE DEC 3 2013/
UPDATE...
PARTLY CLOUDY TO MOSTLY SUNNY SKIES PREVAIL ACROSS SOUTH FLORIDA
THIS MORNING. A FEW LIGHT SHOWERS ARE CURRENTLY SEEN ACROSS THE
GULF WATERS. LATEST HRRR DEPICTS THESE SHOWERS SPREADING ACROSS
PORTIONS OF THE INTERIOR THROUGH THE AFTERNOON. MADE MINOR TWEAKS
TO THE ONGOING FORECAST. UPDATE SENT.
PREV DISCUSSION... /ISSUED 554 AM EST TUE DEC 3 2013/
AVIATION...
HIGH PRESSURE WILL KEEP VFR CONDITIONS THROUGH THE TAF PERIOD,
WITH POSSIBLE BRIEF MVFR THIS MORNING DUE TO SOME LOWER CIGS.
HOWEVER, THERE IS A GREAT AMOUNT OF UNCERTAINTY WITH THIS, THUS
BEING LEFT OUT OF THE TAFS AT THIS TIME. THERE IS A MID LEVEL DECK
OF CLOUDS MOVING ACROSS SOUTH FLORIDA THIS MORNING. THIS HAS KEPT
FOG FROM FORMING AND IS EXPECTED TO REMAIN ABOVE 5000 FT.
SKIES SHOULD BEGIN TO CLEAR SOME LATER THIS MORNING, BECOMING A
SCT DECK. WINDS WILL PICK UP OUT OF THE SOUTHEAST BETWEEN 5 AND 10
KTS MID MORNING.
PREV DISCUSSION... /ISSUED 320 AM EST TUE DEC 3 2013/
DISCUSSION...
THE MAIN SURFACE FEATURES ACROSS THE REGION INCLUDE WEAK HIGH
PRESSURE ACROSS THE SOUTHEASTERN GULF THAT EXTENDS INTO SOUTH
FLORIDA AND A WEAK LOW OFF THE COAST OF THE CAROLINAS. THIS
SYNOPTIC SITUATION WILL MAINTAIN LIGHT WINDS ACROSS THE REGION
TODAY WHILE LOW LEVEL MOISTURE AND LOW LEVEL STRATUS CONTINUES TO
LINGER ACROSS THE REGION EARLY THIS MORNING. AT THE UPPER LEVELS A
TROUGH CONTINUES TO BUILD INTO THE WESTERN ATLANTIC TO THE EAST OF
THE SOUTHEASTERN STATES WHILE THE SOUTHERN EXTENT OF THE JET
STREAM IS POSITIONED ACROSS SOUTH FLORIDA AND THE FLORIDA STRAITS
EARLY THIS MORNING. RECENT WATER VAPOR IMAGERY INDICATES DRY MID
TO UPPER LEVEL AIR BUILDING ACROSS MOST OF THE FLORIDA PENINSULA
BUT MOISTURE CONTINUES ACROSS THE SOUTHERN HALF OF SOUTH FLORIDA.
FOR TODAY...GIVEN THE LINGERING MOISTURE IN THE GULF AND THE
AFOREMENTIONED JET STREAM PASSING ACROSS THE REGION THERE MAY BE A
SLIGHT CHANCE OF A FEW SHOWERS ACROSS THE GULF WATERS AND THE
NAPLES METRO AREA...BUT LOW CONFIDENCE AS THE MID TO UPPER LEVELS
WILL CONTINUE A DRYING TREND AS THE DAY CONTINUES. BUT THE
GUIDANCE INDICATES THAT THE LOW LEVEL MOISTURE AND ASSOCIATED
STRATUS WILL LIKELY LINGER ACROSS THE REGION TODAY.
FOR WEDNESDAY THROUGH FRIDAY...BY WEDNESDAY THE JET STREAM IS
FORECAST TO START LIFTING NORTH OF THE REGION WITH A MID TO UPPER
LEVEL RIDGE BUILDING WESTWARD AND SURFACE HIGH PRESSURE WILL BUILD
BACK INTO THE REGION FROM THE WESTERN ATLANTIC. WHILE LOW LEVEL
SOUTHERLY FLOW WILL MAINTAIN LOW LEVEL MOISTURE ACROSS THE
AREA...MAINLY STABLE WEATHER CONDITIONS ARE EXPECTED. HIGH
PRESSURE WILL CONTINUE TO BUILD WESTWARD ACROSS THE FLORIDA PENINSULA
THURSDAY AND FRIDAY WITH STABLE WEATHER CONDITIONS FORECAST TO
CONTINUE.
FOR THE UPCOMING WEEKEND...BY SATURDAY A COLD FRONT IS FORECAST TO
BECOME STATIONARY ACROSS THE SOUTHEAST U.S. WHILE HIGH PRESSURE
REMAINS IN PLACE ACROSS SOUTH FLORIDA AND ADJACENT WATERS WITH
MAINLY STABLE WEATHER FORECAST TO CONTINUE THROUGH THE WEEKEND.
THE EXTENDED GUIDANCE INDICATES THAT THE FRONT COULD ENTER CENTRAL
FLORIDA BY TUESDAY.
MARINE...
WINDS ARE FORECAST TO BE 10 KNOTS OR LESS THROUGH WEDNESDAY WITH
MAINLY TRANQUIL SEAS EXPECTED. BY THURSDAY THE PRESSURE GRADIENT
INCREASES ACROSS THE WESTERN ATLANTIC WITH EASTERLY FLOW IN THE 10
TO 15 KNOT RANGE FORECAST AND IS FORECAST TO PERSIST IN THAT RANGE
INTO THE UPCOMING WEEKEND WITH GULF STREAM SEAS FROM 2 TO 4 FEET
THROUGH THAT PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 66 81 69 81 / 10 0 10 -
FORT LAUDERDALE 68 81 72 82 / 10 0 - -
MIAMI 68 81 71 82 / 10 0 - -
NAPLES 64 82 65 85 / 10 - 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS MIAMI FL
1026 AM EST TUE DEC 3 2013
.UPDATE...
PARTLY CLOUDY TO MOSTLY SUNNY SKIES PREVAIL ACROSS SOUTH FLORIDA
THIS MORNING. A FEW LIGHT SHOWERS ARE CURRENTLY SEEN ACROSS THE
GULF WATERS. LATEST HRRR DEPICTS THESE SHOWERS SPREADING ACROSS
PORTIONS OF THE INTERIOR THROUGH THE AFTERNOON. MADE MINOR TWEAKS
TO THE ONGOING FORECAST. UPDATE SENT.
&&
.PREV DISCUSSION... /ISSUED 554 AM EST TUE DEC 3 2013/
AVIATION...
HIGH PRESSURE WILL KEEP VFR CONDITIONS THROUGH THE TAF PERIOD,
WITH POSSIBLE BRIEF MVFR THIS MORNING DUE TO SOME LOWER CIGS.
HOWEVER, THERE IS A GREAT AMOUNT OF UNCERTAINTY WITH THIS, THUS
BEING LEFT OUT OF THE TAFS AT THIS TIME. THERE IS A MID LEVEL DECK
OF CLOUDS MOVING ACROSS SOUTH FLORIDA THIS MORNING. THIS HAS KEPT
FOG FROM FORMING AND IS EXPECTED TO REMAIN ABOVE 5000 FT.
SKIES SHOULD BEGIN TO CLEAR SOME LATER THIS MORNING, BECOMING A
SCT DECK. WINDS WILL PICK UP OUT OF THE SOUTHEAST BETWEEN 5 AND 10
KTS MID MORNING.
PREV DISCUSSION... /ISSUED 320 AM EST TUE DEC 3 2013/
DISCUSSION...
THE MAIN SURFACE FEATURES ACROSS THE REGION INCLUDE WEAK HIGH
PRESSURE ACROSS THE SOUTHEASTERN GULF THAT EXTENDS INTO SOUTH
FLORIDA AND A WEAK LOW OFF THE COAST OF THE CAROLINAS. THIS
SYNOPTIC SITUATION WILL MAINTAIN LIGHT WINDS ACROSS THE REGION
TODAY WHILE LOW LEVEL MOISTURE AND LOW LEVEL STRATUS CONTINUES TO
LINGER ACROSS THE REGION EARLY THIS MORNING. AT THE UPPER LEVELS A
TROUGH CONTINUES TO BUILD INTO THE WESTERN ATLANTIC TO THE EAST OF
THE SOUTHEASTERN STATES WHILE THE SOUTHERN EXTENT OF THE JET
STREAM IS POSITIONED ACROSS SOUTH FLORIDA AND THE FLORIDA STRAITS
EARLY THIS MORNING. RECENT WATER VAPOR IMAGERY INDICATES DRY MID
TO UPPER LEVEL AIR BUILDING ACROSS MOST OF THE FLORIDA PENINSULA
BUT MOISTURE CONTINUES ACROSS THE SOUTHERN HALF OF SOUTH FLORIDA.
FOR TODAY...GIVEN THE LINGERING MOISTURE IN THE GULF AND THE
AFOREMENTIONED JET STREAM PASSING ACROSS THE REGION THERE MAY BE A
SLIGHT CHANCE OF A FEW SHOWERS ACROSS THE GULF WATERS AND THE
NAPLES METRO AREA...BUT LOW CONFIDENCE AS THE MID TO UPPER LEVELS
WILL CONTINUE A DRYING TREND AS THE DAY CONTINUES. BUT THE
GUIDANCE INDICATES THAT THE LOW LEVEL MOISTURE AND ASSOCIATED
STRATUS WILL LIKELY LINGER ACROSS THE REGION TODAY.
FOR WEDNESDAY THROUGH FRIDAY...BY WEDNESDAY THE JET STREAM IS
FORECAST TO START LIFTING NORTH OF THE REGION WITH A MID TO UPPER
LEVEL RIDGE BUILDING WESTWARD AND SURFACE HIGH PRESSURE WILL BUILD
BACK INTO THE REGION FROM THE WESTERN ATLANTIC. WHILE LOW LEVEL
SOUTHERLY FLOW WILL MAINTAIN LOW LEVEL MOISTURE ACROSS THE
AREA...MAINLY STABLE WEATHER CONDITIONS ARE EXPECTED. HIGH
PRESSURE WILL CONTINUE TO BUILD WESTWARD ACROSS THE FLORIDA PENINSULA
THURSDAY AND FRIDAY WITH STABLE WEATHER CONDITIONS FORECAST TO
CONTINUE.
FOR THE UPCOMING WEEKEND...BY SATURDAY A COLD FRONT IS FORECAST TO
BECOME STATIONARY ACROSS THE SOUTHEAST U.S. WHILE HIGH PRESSURE
REMAINS IN PLACE ACROSS SOUTH FLORIDA AND ADJACENT WATERS WITH
MAINLY STABLE WEATHER FORECAST TO CONTINUE THROUGH THE WEEKEND.
THE EXTENDED GUIDANCE INDICATES THAT THE FRONT COULD ENTER CENTRAL
FLORIDA BY TUESDAY.
MARINE...
WINDS ARE FORECAST TO BE 10 KNOTS OR LESS THROUGH WEDNESDAY WITH
MAINLY TRANQUIL SEAS EXPECTED. BY THURSDAY THE PRESSURE GRADIENT
INCREASES ACROSS THE WESTERN ATLANTIC WITH EASTERLY FLOW IN THE 10
TO 15 KNOT RANGE FORECAST AND IS FORECAST TO PERSIST IN THAT RANGE
INTO THE UPCOMING WEEKEND WITH GULF STREAM SEAS FROM 2 TO 4 FEET
THROUGH THAT PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 79 66 81 69 / - 10 0 10
FORT LAUDERDALE 79 68 81 72 / - 10 0 -
MIAMI 80 68 81 71 / - 10 0 -
NAPLES 78 64 82 65 / 20 10 - 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
253 PM EST TUE DEC 3 2013
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
WARM FRONT SHOULD BE MOVING NORTH THROUGH THE CWA THIS EVENING AND
OVERNIGHT. GFS/NAM KEEP ENHANCED MOISTURE ACROSS THE CWA THROUGH
WEDNESDAY MORNING...AND HRRR IS INDICATING AN EXPANSION OF THE RAIN
AREA AS IT MOVES NORTHEAST TONIGHT. HAVE KEPT LIKELY POPS OVER MUCH
OF THE CENTRAL TO NE ZONES WITH A GRADUAL DECREASE AFTER 06Z. SOME
LINGERING LOW POPS WEDNESDAY MORNING MAINLY NORTH. WEAK UPPER RIDGE
BUILDS OVER THE CWA WEDNESDAY AFTERNOON AND SO HAVE REMOVED THE POPS
FOR THAT TIME. STRONG SOUTHERLY FLOW WILL BRING ANOTHER INCREASE IN
MOISTURE TO THE CWA LATE WEDNESDAY NIGHT AHEAD OF AN APPROACHING
COLD FRONT. HAVE INTRODUCED POPS AGAIN TOWARD THURSDAY MORNING. AIR
MASS LOOKS STABLE FOR THE SHORT TERM...SO HAVE NO MENTION OF
THUNDER. INSTABILITY STARTS TO INCREASE BY 12Z THURSDAY. EXPECT WARM
TEMPERATURES WITH THE STRONG SOUTHERLY FLOW. OVERNIGHT MINS MAY
APPROACH RECORD VALUES.
41
.LONG TERM /THURSDAY THROUGH TUESDAY/...
ONLY MINOR CHANGES MADE TO THE EXTENDED WITH THIS PACKAGE. REFINED
TIMING OF POPS FOR EARLY THURSDAY AND MADE SOME MINOR ADJUSTMENTS
MAINLY TO LOW TEMPS THROUGH THE EXTENDED. GUIDANCE COMING INTO
SLIGHTLY BETTER AGREEMENT FOR THE FINAL FROPA AFTER THE WEEKEND
CAD EVENT /GFS COMING MUCH BETTER IN LINE WITH THE ECMWF/ SO MADE
SOME ADDITIONAL ADJUSTMENTS TO TEMPS EARLY NEXT WEEK...BUT OVERALL
VERY LITTLE CHANGE. STILL SOME CONCERN ABOUT THUNDERSTORMS
THURSDAY AND FRIDAY AFTERNOON...WITH INCREASING CONCERN FOR
ISOLATED SEVERE. SHERB VALUES HOVER JUST BELOW THE CRITICAL
THRESHOLD OF 1 FOR HIGH SHEAR LOW CAPE SEVERE WEATHER BOTH
AFTERNOONS AND SPC HAS ADDED A GENERAL THUNDER AREA FOR DAY 3
/THURSDAY/. WILL CONTINUE TO MONITOR EVOLUTION OF THE FORECAST.
TDP
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
/ISSUED AT 405 AM EST TUE DEC 3 2013/
AN UNSETTLED WEATHER PATTERN WILL PREDOMINATE FOR MUCH OF THE
EXTENDED PERIOD.
CHANCES FOR LIGHT RAIN WEDNESDAY NIGHT INCREASING OVER MAINLY N GA
AS AN INCREASINGLY WARM AND MOIST SOUTHERLY LOW LEVEL FLOW
CONTINUES AHEAD OF A SLOW MOVING COLD FRONT MOVING ACROSS THE MID
U.S.
THE GFS AND EUROPEAN ARE SIMILAR WITH BRINGING THE FRONT TO THE TN
VALLEY LATE THURSDAY WITH SHOWERS LIKELY FOR N AND PORTIONS OF
CENTRAL GA WITH SMALL CHANCES FOR THUNDERSTORMS. MUCAPE FORECAST IN
THE 200-600 RANGE. FOR THE MOST PART PRECIP EXPECTED TO BE LIGHT AND
POSSIBLY BRIEFLY MODERATE.
FRONT EXPECTED TO MOVE INTO N GA FRIDAY AND TO CENTRAL TO S GA LATE
SATURDAY. MAINLY SMALL THUNDERSTORM CHANCES ASSOCIATED AS AN AXIS OF
MUCAPE MOVES WITH THE FRONT INTO FRIDAY NIGHT BEFORE WEAKENING.
HIGHEST POPS EXPECTED TO BE OVER N GA FRIDAY/FRIDAY NIGHT. SATURDAY
POPS FOR CENTRAL GA MAY NOT BE HIGH ENOUGH WITH CHANCE SHOWERS
FORECAST.
THE TREND FOR MUCH WARMER TEMPERATURES WILL CONTINUE UNTIL THE FRONT
PASSES BY. EXPECTING NEAR-RECORD OR RECORD WARM MIN TEMPS FOR
FRIDAY MORNING.
WITH HIGH PRESSURE MOVING ACROSS THE NORTHERN STATES SATURDAY NIGHT
AND SUNDAY...GFS AND EUROPEAN ARE SIMILAR WITH FORECASTING A COLD
AIR DAMMING EVENT THAT WILL INCREASE RAIN CHANCES ACROSS N AND
PORTIONS OF CENTRAL GA. BY LATE DAY SUNDAY THE GFS AND EUROPEAN
BEGIN TO DIFFER THAT BECOMES EVEN GREATER THROUGH MONDAY. THE GFS
MOVES ANOTHER FRONT ACROSS THE AREA MONDAY DRYING THINGS OUT BY DAYS
END. THE EUROPEAN IS MUCH SLOWER WITH THE FRONT OVER NW GA AT DAYS
END MONDAY MAKING THE FORECAST HIGH UNCERTAIN.
BDL
&&
.AVIATION...
18Z UPDATE...
IFR CEILINGS SHOULD PREVAIL ACROSS THE TAF SITES THROUGH MOST OF THE
AFTERNOON AND INTO THE EVENING. HOWEVER...THERE WILL BE PERIODS OF
MVFR. RAIN SHOULD REDEVELOP AND SPREAD NORTHEAST LATE AFTERNOON AND
EVENING BEFORE DIMINISHING LATER TONIGHT. LIFR DEVELOPING ACROSS THE
TAF SITES AFTER 06Z...GRADUALLY IMPROVING AFTER 15Z WEDNESDAY. WINDS
LIGHT SOUTHEAST OVERNIGHT BECOMING SOUTH TO SOUTHWEST AFTER 12Z.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON ALL ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 52 68 57 72 / 70 20 20 40
ATLANTA 55 69 62 72 / 60 20 20 50
BLAIRSVILLE 49 63 57 67 / 50 20 30 60
CARTERSVILLE 52 68 60 72 / 50 20 30 50
COLUMBUS 57 75 65 76 / 60 10 20 40
GAINESVILLE 50 65 59 69 / 60 20 30 50
MACON 55 74 61 75 / 70 10 20 30
ROME 53 69 61 73 / 50 20 40 60
PEACHTREE CITY 51 70 60 73 / 70 10 20 50
VIDALIA 57 76 59 76 / 40 10 10 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...41
LONG TERM....TDP
AVIATION...41
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
646 AM EST TUE DEC 3 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OVER THE REGION TONIGHT AS LOW
PRESSURE OFF THE COAST MOVES NORTHWARD. THE AREA OF HIGH PRESSURE
WILL MOVE OFF THE COAST TUESDAY ALLOWING A WARM FRONT TO LIFT
NORTH THROUGH THE AREA. A SIGNIFICANT WARMING TREND WILL BEGIN
MIDWEEK WITH A COLD FRONT BRINGING A CHANCE OF RAIN AND COOLER
TEMPERATURES FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PATCHY LIGHT RAIN ASSOCIATED WITH WEAK ISENTROPIC LIFT AND SHORT
WAVE TROUGH CONTINUES TO SPREAD INTO THE WESTERN MIDLANDS EARLY
THIS MORNING. LITTLE PROGRESS EAST DUE TO DRIER AIR MASS...LIMITED
PRECIPITABLE WATER. MORE ORGANIZED AREA OF RAIN OVER CENTRAL
GEORGIA MOVING TOWARD CSRA. LATEST HRRR GUIDANCE SUGGEST IT WILL
HOLD TOGETHER AND MOVE INTO THE AGS AREA. WILL RAISE POPS TO
LIKELY THERE FOR THIS MORNING.
UPPER LEVEL FLOW ZONAL TODAY...WEAK SHORT WAVE TROUGHS WILL MOVE
ACROSS THE REGION. SURFACE RIDGE MOVING OFF THE COAST. WARM FRONT
ACROSS SOUTHERN ALABAMA/SOUTH GEORGIA WILL BE LIFTING TO THE
NORTHEAST DURING THE DAY. WEAK ISENTROPIC LIFT/MOISTURE FLUX WILL
CONTINUE AHEAD OF THE WARM FRONT...ESPECIALLY ACROSS THE WESTERN
MIDLANDS/CSRA. PRECIPITABLE WATER REMAINS LOW...SREF INDICATES LOW
QPF. RAISE POPS FROM PREVIOUS FORECAST. TEMPERATURES SIMILAR TO
YESTERDAY WITH CONSIDERABLE CLOUDS AHEAD OF WARM FRONT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
WITH WARM FRONT LIFTING NORTH ACROSS THE AREA TONIGHT...HIGHEST
POPS DURING THE OVERNIGHT...LIKELY IN THE PIEDMONT/NORTH MIDLANDS
WHERE ISENTROPIC LIFT APPEARS TO BE STRONGEST. TEMPERATURES MAY
RISE TOWARD DAYBREAK. CHANCE SHOWERS EARLY WEDNESDAY BUT EXPECT
BREAKS IN THE CLOUDS BY AFTERNOON WITH DRYING ALOFT...WARM
ADVECTION SUPPORTS ABOVE NORMAL TEMPERATURES IN THE 70S. SHORT
WAVE RIDGE OVER THE AREA LATE WEDNESDAY THROUGH WEDNESDAY NIGHT
SHIFTS OFF THE COAST. UPPER LEVEL RIDGE OFFSHORE SOUTHEASTERN
STATES INTO GULF OF MEXICO IN RESPONSE TO UPSTREAM AMPLIFIED TROUGH
IN THE WESTERN STATES. SURFACE COLD FRONT MOVING INTO THE
TENNESSEE/OHIO VALLEY. WARM ADVECTION/MOISTURE FLUX INCREASING
ACROSS REGION...BEST CHANCE RAIN REMAINS TO THE WEST DUE TO
RIDGING EAST. RAISED POPS SLIGHTLY FROM PREVIOUS FORECAST DUE TO
LIKELY INCREASE IN MOISTURE. TEMPERATURES ABOVE NORMAL IN THE LOW
TO MID 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MEDIUM RANGE MODELS APPEAR TO BE CONVERGING ON A SOLUTION. THE
MAIN FORECAST PROBLEM REVOLVES AROUND THE TIMING OF A COLD FRONT
IN THE FRIDAY NIGHT INTO EARLY SATURDAY PERIOD AND SUBSEQUENT
WEDGE SETUP FOR EARLY NEXT WEEK.
THE MODELS DEPICT A LARGE AND EXPANSIVE UPPER TROUGH ACROSS THE
WESTERN UNITED STATES WITH DOWNSTREAM RIDGING ACROSS THE
SOUTHEASTERN STATES INTO THE MID ATLANTIC REGION. A SLOW MOVING
FRONTAL BOUNDARY IS EXPECTED TO STALL JUST WEST OF THE FORECAST AREA
INTO FRIDAY AS DEEP SOUTHWESTERLY FLOW ALOFT BECOMES NEARLY
PARALLEL TO THE FRONT. BOTH THE GFS AND ECMWF PUSH THE COLD FRONT
THROUGH THE FORECAST AREA FRIDAY NIGHT INTO EARLY SATURDAY... WITH
WEDGE CONDITIONS DEVELOPING SATURDAY AND LINGERING PERHAPS INTO
MONDAY.
INCREASING CHANCES OF RAIN FRIDAY INTO THE WEEKEND.
UNCERTAINTY REMAINS REGARDING THE PRECIPITATION AMOUNT AND EVEN
POSSIBLE THUNDERSTORMS WITH CONSIDERABLE SPREAD IN THE GUIDANCE.
THE SIGNIFICANT WARM UP CONTINUES THURSDAY AND FRIDAY UNDER THE
INFLUENCE OF THE UPPER RIDGE AND DEEP SOUTHERLY FLOW. TEMPERATURES
FALL TO AT OR BELOW NORMAL SATURDAY THROUGH MONDAY.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS THROUGH MUCH OF THE PERIOD...WITH LOWERING CONDITIONS
EXPECTED AFTER 03/18Z.
WEAK WARM AIR ADVECTION AND ISENTROPIC ASCENT CONTINUE ACROSS THE
REGION WITH AS A SHORT WAVE TROUGH CURRENTLY CROSSING WESTERN GA.
WIDELY SCATTERED RAIN SHOWERS CONTINUE ACROSS THE AREA AND WILL
CONTINUE TO HANDLE WITH VCSH AS SHOWERS ARE NOT PRODUCING
RESTRICTIONS ATTM. INCREASING CHANCES OF RAIN WILL MOVE INTO THE
TAF SITES THIS AFTERNOON AS THE SHORT WAVE CROSSES THE AREA.
EXPECT CIG RESTRICTIONS BEGINNING BY 21Z AND PERSISTING INTO
TONIGHT. FOG IS ALSO A CONCERN AFTER 04/05Z WITH MODELS INDICATING
INCREASING POTENTIAL. HAVE INCLUDED MVFR IN FOG/STRATUS FROM
AROUND 04/06Z ONWARD AND WILL ADJUST AS CONFIDENCE IMPROVES.
EXTENDED AVIATION OUTLOOK...STRATUS AND FOG WILL LIKELY OCCUR DURING
THE EARLY MORNING HOURS WEDNESDAY AND THURSDAY ASSOCIATED WITH A
WARM FRONT. LOW CONFIDENCE FORECAST FOR FRIDAY AND SATURDAY WITH
PERIODS OF MVFR...AND POSSIBLY LOWER.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
546 AM EST TUE DEC 3 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OVER THE REGION TONIGHT AS LOW
PRESSURE OFF THE COAST MOVES NORTHWARD. THE AREA OF HIGH PRESSURE
WILL MOVE OFF THE COAST TUESDAY ALLOWING A WARM FRONT TO LIFT
NORTH THROUGH THE AREA. A SIGNIFICANT WARMING TREND WILL BEGIN
MIDWEEK WITH A COLD FRONT BRINGING A CHANCE OF RAIN AND COOLER
TEMPERATURES FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PATCHY LIGHT RAIN ASSOCIATED WITH WEAK ISENTROPIC LIFT AND SHORT
WAVE TROUGH CONTINUES TO SPREAD INTO THE WESTERN MIDLANDS EARLY
THIS MORNING. LITTLE PROGRESS EAST DUE TO DRIER AIR MASS...LIMITED
PRECIPITABLE WATER. MORE ORGANIZED AREA OF RAIN OVER CENTRAL
GEORGIA MOVING TOWARD CSRA. LATEST HRRR GUIDANCE SUGGEST IT WILL
HOLD TOGETHER AND MOVE INTO THE AGS AREA. WILL RAISE POPS TO
LIKELY THERE FOR THIS MORNING.
UPPER LEVEL FLOW ZONAL TODAY...WEAK SHORT WAVE TROUGHS WILL MOVE
ACROSS THE REGION. SURFACE RIDGE MOVING OFF THE COAST. WARM FRONT
ACROSS SOUTHERN ALABAMA/SOUTH GEORGIA WILL BE LIFTING TO THE
NORTHEAST DURING THE DAY. WEAK ISENTROPIC LIFT/MOISTURE FLUX WILL
CONTINUE AHEAD OF THE WARM FRONT...ESPECIALLY ACROSS THE WESTERN
MIDLANDS/CSRA. PRECIPITABLE WATER REMAINS LOW...SREF INDICATES LOW
QPF. RAISE POPS FROM PREVIOUS FORECAST. TEMPERATURES SIMILAR TO
YESTERDAY WITH CONSIDERABLE CLOUDS AHEAD OF WARM FRONT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
WITH WARM FRONT LIFTING NORTH ACROSS THE AREA TONIGHT...HIGHEST
POPS DURING THE OVERNIGHT...LIKELY IN THE PIEDMONT/NORTH MIDLANDS
WHERE ISENTROPIC LIFT APPEARS TO BE STRONGEST. TEMPERATURES MAY
RISE TOWARD DAYBREAK. CHANCE SHOWERS EARLY WEDNESDAY BUT EXPECT
BREAKS IN THE CLOUDS BY AFTERNOON WITH DRYING ALOFT...WARM
ADVECTION SUPPORTS ABOVE NORMAL TEMPERATURES IN THE 70S. SHORT
WAVE RIDGE OVER THE AREA LATE WEDNESDAY THROUGH WEDNESDAY NIGHT
SHIFTS OFF THE COAST. UPPER LEVEL RIDGE OFFSHORE SOUTHEASTERN
STATES INTO GULF OF MEXICO IN RESPONSE TO UPSTREAM AMPLIFIED TROUGH
IN THE WESTERN STATES. SURFACE COLD FRONT MOVING INTO THE
TENNESSEE/OHIO VALLEY. WARM ADVECTION/MOISTURE FLUX INCREASING
ACROSS REGION...BEST CHANCE RAIN REMAINS TO THE WEST DUE TO
RIDGING EAST. RAISED POPS SLIGHTLY FROM PREVIOUS FORECAST DUE TO
LIKELY INCREASE IN MOISTURE. TEMPERATURES ABOVE NORMAL IN THE LOW
TO MID 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MEDIUM RANGE MODELS APPEAR TO BE CONVERGING ON A SOLUTION. THE
MAIN FORECAST PROBLEM REVOLVES AROUND THE TIMING OF A COLD FRONT
IN THE FRIDAY NIGHT INTO EARLY SATURDAY PERIOD AND SUBSEQUENT
WEDGE SETUP FOR EARLY NEXT WEEK.
THE MODELS DEPICT A LARGE AND EXPANSIVE UPPER TROUGH ACROSS THE
WESTERN UNITED STATES WITH DOWNSTREAM RIDGING ACROSS THE
SOUTHEASTERN STATES INTO THE MID ATLANTIC REGION. A SLOW MOVING
FRONTAL BOUNDARY IS EXPECTED TO STALL JUST WEST OF THE FORECAST AREA
INTO FRIDAY AS DEEP SOUTHWESTERLY FLOW ALOFT BECOMES NEARLY
PARALLEL TO THE FRONT. BOTH THE GFS AND ECMWF PUSH THE COLD FRONT
THROUGH THE FORECAST AREA FRIDAY NIGHT INTO EARLY SATURDAY... WITH
WEDGE CONDITIONS DEVELOPING SATURDAY AND LINGERING PERHAPS INTO
MONDAY.
INCREASING CHANCES OF RAIN FRIDAY INTO THE WEEKEND.
UNCERTAINTY REMAINS REGARDING THE PRECIPITATION AMOUNT AND EVEN
POSSIBLE THUNDERSTORMS WITH CONSIDERABLE SPREAD IN THE GUIDANCE.
THE SIGNIFICANT WARM UP CONTINUES THURSDAY AND FRIDAY UNDER THE
INFLUENCE OF THE UPPER RIDGE AND DEEP SOUTHERLY FLOW. TEMPERATURES
FALL TO AT OR BELOW NORMAL SATURDAY THROUGH MONDAY.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS THROUGH MUCH OF THE PERIOD...WITH LOWERING CONDITIONS
EXPECTED AFTER 03/18Z.
UPPER LEVEL TROUGH CONTINUES TO SWING OFFSHORE WITH SHORT WAVES
MOVING THROUGH THE REGION. WITH WEAK WARM AIR ADVECTION AND
ISENTROPIC ASCENT EXPECT SOME LIGHT SHOWERS TO CROSS THE TAF SITES
THROUGH THE PERIOD. SHOWERS CURRENTLY MOVING TOWARD THE TAF SITES
ARE LIGHT ENOUGH THAT NO RESTRICTIONS ARE EXPECTED THROUGH THE FIRST
HALF OF THE PERIOD. WITH ADDITIONAL MOISTURE MOVING INTO THE REGION
LATER IN THE PERIOD CIGS WILL BEGIN LOWERING WITH MVFR CIGS ARRIVING
AROUND 03/21Z AND PERSISTING THROUGH THE END OF THE PERIOD.
ADDITIONAL SHOWERS ARE POSSIBLE WITH THE LOWER CIGS...HOWEVER VSBY
RESTRICTIONS ARE NOT EXPECTED AS RAINFALL WITH BE LIGHT.
EXTENDED AVIATION OUTLOOK...STRATUS AND FOG WILL LIKELY OCCUR MAINLY
DURING THE EARLY MORNING HOURS WEDNESDAY AND THURSDAY ASSOCIATED
WITH A WARM FRONT. LOW CONFIDENCE FORECAST FOR FRIDAY AND SATURDAY
WITH PERIODS OF MVFR...AND POSSIBLY LOWER.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
77
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
228 PM CST TUE DEC 3 2013
.DISCUSSION...
1055 AM CST
HAVE EXTENDED THE DENSE FOG ADVISORY A COUPLE HOURS ACROSS NORTH
CENTRAL IL AS WELL AS EXPAND IT EASTWARD INTO THE FAR WESTERN
CHICAGO SUBURBS. ALSO HAVE BUMPED DOWN HIGH TEMPERATURES SEVERAL
DEGREES GIVEN THE LIMITED WARM ADVECTION NOT BEING ABLE TO OFFSET
NULL SOLAR HEATING.
OBSERVED VISIBILITY AND WEBCAMS ACROSS MUCH OF NORTH CENTRAL AND
NORTHWEST IL INDICATE LITTLE IMPROVEMENT HAS OCCURRED WITH T/TD
SPREADS ALMOST ENTIRELY AT 1F OR LESS. WITH TEMPERATURES STILL
AROUND 40 AND QUITE A WAYS FROM THAT 48-50 NEEDED ON THE 12Z DVN
RAOB TO BREAK THROUGH INTO BETTER MIXING...NOT EXPECTING RAPID
IMPROVEMENT. HIGH RES MODELS AND ENSEMBLES SUCH AS THE HRRR AND
NARRE-TL INDICATE SLIGHT VISIBILITY IMPROVEMENT THIS
AFTERNOON...WHILE ALSO BOTH INDICATING SUSCEPTIBILITY TO DROPPING
RIGHT BACK INTO DENSE FOG AFTER DARK WHICH CONCEPTUALLY MAKES
SENSE WITH THE AREA ALONG/NORTH OF THE WARM FRONT. HOW QUICKLY THE
WARM FRONT PROGRESSES NORTHWARD TONIGHT IS HIGHLY UNCERTAIN AND
SOMETHING MODELS MAY PROGRESS TOO QUICKLY. HAVE FOR THE TIME BEING
ADDED AREAS OF FOG MENTION ACROSS THE CWA.
INTERMITTENT LIGHT RAIN/DRIZZLE SHOULD CONTINUE WITH ANOTHER
SMALL SCALE MID-LEVEL IMPULSE HELPING TO BRING A BIT OF ENHANCED
WARM AIR ADVECTION/ISENTROPIC ASCENT AND JUST SOME BROAD AND WEAK
OMEGA.
TEMPERATURES WILL OOZE UPWARD AND MAY REACH THEIR MAXS TOWARD 4-5
PM...ABOUT 1-2 HRS LATER THAN TYPICAL THIS TIME OF YEAR.
TEMPERATURES SHOULD BASICALLY HOLD STEADY INTO THE EVE AND MAY
CLIMB LATER INTO THE NIGHT.
MTF
//PREV DISCUSSION...
330 AM CST
FORECAST FOCUS REMAINS LARGELY ON THE NEAR TERM THIS MORNING...
NAMELY PRECIPITATION AND TEMPERATURE TRENDS TODAY THROUGH WEDNESDAY
AS DEEP LOW PRESSURE SYSTEM DEVELOPS IN RESPONSE TO AMPLIFICATION OF
UPPER TROUGH ACROSS THE WESTERN/CENTRAL CONUS. DAYS 3-7 CONTINUE TO
FEATURE MUCH COLDER THAN AVERAGE TEMPERATURES...WITH THE POTENTIAL
FOR A COUPLE OF LIGHT SNOW EVENTS MAINLY ACROSS THE FAR SOUTHEAST
LATE THURSDAY-FRIDAY...AND FOR MOST OF THE AREA SUNDAY/SUNDAY NIGHT.
00Z RAOB ANALYSIS INDICATES FAIRLY ZONAL FLOW PATTERN ACROSS THE
CENTRAL CONUS...WITH A DEEP SHORT WAVE TROUGH DIGGING SOUTHEAST
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SEVERAL RELATIVELY MINOR
AMPLITUDE SHORT WAVES WERE NOTED DOWNSTREAM ACROSS THE MIDWEST...
EMANATING FROM STRONG JET STREAK DEVELOPS AROUND THE SOUTHERN
PERIPHERY OF THE DIGGING TROUGH. ONE SUCH WAVE WAS NOTED IN WATER
VAPOR IMAGERY OVER THE UPPER MISSISSIPPI VALLEY EARLY THIS
MORNING...WHICH WAS RESPONSIBLE FOR AN AREA OF WARM ADVECTION
PRECIPITATION THAT MOVED ACROSS THE FORECAST AREA OVERNIGHT AND WAS
NOW EAST OF THE REGION. A COUPLE OF MORE SUBTLE MID-LEVEL WAVES WERE
NOTED IN THE SATELLITE IMAGERY...ONE APPROACHING QUICKLY FROM
EASTERN IA...AND THE OTHER UPSTREAM ACROSS WESTERN NEBRASKA. THESE
FEATURES WILL RIPPLE QUICKLY EAST ACROSS THE AREA TODAY...MAINLY
WORKING TO MAINTAIN SOUTHERLY FLOW AND CONTINUED WARM ADVECTION INTO
THE MIDWEST. WHILE SOME SPOTTY LIGHT RAIN IS POSSIBLE WITH ANY OF
THESE SUBTLE FEATURES...UPSTREAM SOUNDINGS FROM OMA/TOP/SGF INDICATE
FAIRLY DRY MID-LEVELS. FORECAST SOUNDINGS MAINTAIN THIS DRY LAYER
ROUGHLY BETWEEN 850-650 MB WHICH SUGGESTS MAINLY SCATTERED LIGHT
RAIN OR SOME DRIZZLE WITH ONLY LIGHT QPF AMOUNTS TODAY-TONIGHT AS
FORCING WITH THESE WAVES ACT ON MOIST LOW LEVELS OR BRIEF POCKETS OF
ENHANCED MID-LEVEL MOISTURE.
WITH ONGOING WARM ADVECTION...SURFACE TEMPERATURES AND DEW POINTS
WILL CONTINUE TO SLOWLY RISE AS A WARM FRONT CURRENTLY LIFTING INTO
CENTRAL ILLINOIS MOVES NORTH. WHILE THE BOUNDARY REMAINS A BIT
DIFFUSE EARLY THIS MORNING...THE FRONT SHOULD SHARPEN AND BEGIN TO
MOVE FASTER LATER TODAY AND TONIGHT AS SURFACE LOW PRESSURE DEEPENS
TO OUR WEST ACROSS THE CENTRAL PLAINS IN RESPONSE TO HEIGHT FALLS
WITH DEEPENING WESTERN TROUGH. MODELS ARE IN FAIRLY GOOD AGREEMENT
THAT THE SURFACE WARM FRONT SHOULD LIFT INTO NORTHERN IL BY LATE
AFTERNOON...WITH THE SOUTHERN AND CENTRAL PARTS OF THE CWA GETTING
INTO THE WARM SECTOR. TEMPS SHOULD REACH THE LOW-MID 50S ALONG AND
SOUTH OF I-80 THIS AFTERNOON...WITH 40S TO THE NORTH. IT WILL REMAIN
VERY MILD TONIGHT AS THE WARM FRONT REACHES THE IL/WI BORDER...WITH
OVERNIGHT LOWS HOLDING IN THE 40S ACROSS THE CWA.
GUIDANCE REMAINS IN TWO SEPARATE CAMPS WITH THE HANDLING OF THE MAIN
SURFACE LOW AND COLD FRONT ON WEDNESDAY...WITH THE DOMESTIC MODELS
REMAINING FASTER AND INITIALLY DEEPER BEYOND 30 HOURS THAN THE UK/EC
AND CANADIAN COUNTERPARTS. THE 00Z RUNS OF THE GFS AND TO A GREATER
EXTENT THE WRF HAVE SLOWED HOWEVER...WHICH LENDS SUPPORT TO OUR
FAVORING THE SLOWER SOLUTION OF THE UKMET/ECMWF AND GEM. THUS
CONTINUE TO FAVOR THE SCENARIO OF THE SURFACE LOW LIFTING ACROSS
EASTERN IOWA INTO WI WEDNESDAY AFTERNOON...AND THE TRAILING COLD
FRONT MOVING ACROSS THE WFO LOT FORECAST AREA FAIRLY LATE IN THE
AFTERNOON AND EVENING HOURS. THIS SUPPORTS TEMPS IN THE 50S...AND
EVEN A COUPLE OF 60S FAR SOUTH...WEDNESDAY WITH THE CWA STILL IN THE
WARM SECTOR AHEAD OF THE FRONT. MID-LEVEL MOISTURE CONTINUES TO BE
LIMITED...AND ALTHOUGH LIGHT RAIN/SHOWER CHANCES DO INCREASE WITH
THE APPROACH OF THE LOW/COLD FRONT THE BEST COVERAGE AND RAINFALL
AMOUNTS EXPECTED NORTH OF THE AREA ACROSS WI AND THE NORTHERN LAKES.
THE COLD FRONT PUSHES ACROSS THE AREA WEDNESDAY EVENING...SHUTTING
OFF PRECIP AS MID/UPPER LEVELS DRY OUT. THANKS TO WEST-SOUTHWEST
FLOW ALOFT THE FIRST PUSH OF COLDER AIR IS RELATIVELY WEAK...AS THE
FRONT AND LOW LEVEL BAROCLINIC ZONE SLOW UP FROM THE OHIO VALLEY TO
THE EASTERN LAKES INTO THURSDAY. A COUPLE OF DISTURBANCES RIPPLE
NORTHEAST ALONG THIS BAROCLINIC ZONE LATE THURSDAY INTO FRIDAY...
WITH THE POTENTIAL FOR SOME LIGHT SNOW FROM CENTRAL IL INTO NORTHERN
INDIANA AND MAINLY CLIPPING THE FAR SOUTHEAST PART OF THE CWA. A
SECOND PUSH OF COLDER AIR THEN SPREADS IN THURSDAY NIGHT-FRIDAY AS
THE UPPER LOW PASSES TO THE NORTH AND HEADS INTO EASTERN CANADA.
THIS ALLOWS 850 MB AIR OF -10 TO -15 C ACROSS THE AREA AND TEMPS A
GOOD 8-10F COLDER FRIDAY THAN ON THURSDAY. SOME DIFFERENCES REMAIN
WITH MODEL DETAILS AT THIS TIME...BUT CONTINUE TO FAVOR THE SIMILAR
GEM/ECMWF WHICH SUPPORTS HIGHS ONLY NEAR/AROUND 20 FRIDAY AND
SATURDAY AS ARCTIC HIGH PRESSURE BUILDS ACROSS THE MIDWEST. LOOKS
LIKE AT LEAST SOME SLIGHT MODERATION SUNDAY-MONDAY AS UPPER TROUGH
AMPLIFIES ACROSS THE WESTERN CONUS/NOAM...WITH AN AREA OF LOW
PRESSURE LIFTING ACROSS THE AREA SUNDAY WITH THE POTENTIAL FOR SOME
LIGHT SNOW.
RATZER
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* IFR/LIFR CIGS/VIS LOWERING TO LIFR/VLIFR THIS EVENING/TONIGHT.
* SOUTHEASTERLY WINDS AROUND 10 KT THROUGH EARLY EVENING.
* FOG WITH 1/2SM OVERNIGHT INTO WEDNESDAY MORNING.
* CHANCE OF SHOWERS WEDNESDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE OVER THE SOUTH CENTRAL PLAINS WILL LIFT NORTHEAST
OVER MISSOURI WEDNESDAY MORNING...THEN MOVE NORTHEAST ACROSS
EASTERN IOWA AND NORTHWEST IL EARLY WEDNESDAY AFTERNOON. A WARM
FRONT EXTENDING EAST FROM THIS LOW...CURRENTLY ACROSS CENTRAL IL...
IS EXPECTED TO LIFT NORTH ACROSS THE TERMINALS OVERNIGHT INTO
WEDNESDAY MORNING. HOWEVER...CONFIDENCE REGARDING ITS SPEED AND
LOCATION IS LOW AND THIS CREATES A CHALLENGING FORECAST FOR FOG
POTENTIAL THIS EVENING THROUGH WEDNESDAY MORNING. PREVAILING
VISIBILITIES HAVE REMAINED IN THE 1-2SM WITH RFD NOW SLOWING
APPROACHING 1SM. WITH THE WARM FRONT EXPECTED TO REMAIN SOUTH OF
THE TERMINALS THROUGH AT LEAST THIS EVENING...EXPECT THE VIS TO
LOWER BACK UNDER 1SM THIS EVENING WITH SOME DRIZZLE POSSIBLE. THE
VIS MAY CONTINUE TO LOWER TO 1/2SM OR A 1/4SM AT SOME LOCATIONS...
ESPECIALLY AT RFD. IF THE WARM FRONT IS ABLE TO MOVE ACROSS
NORTHERN IL TONIGHT...VISIBILITIES WILL LIKELY IMPROVE INTO THE
1-2SM RANGE OR BETTER. HOWEVER...ITS POSSIBLE THE FRONT WILL SLOW
OR STALL AND IF THIS OCCURS...VISIBILITIES WILL LIKELY TANK
OVERNIGHT AND PERSIST INTO WEDNESDAY MORNING...WHEN THE WARM FRONT
WILL FINALLY MOVE ACROSS THE AREA.
WIND DIRECTIONS WILL REMAIN SOUTHEASTERLY AROUND 10KTS THIS
AFTERNOON...THEN DIMINISH THIS EVENING. SPECIFIC DIRECTIONS
TONIGHT INTO WEDNESDAY MORNING WILL DEPEND ON THE WARM FRONT
MOVEMENT/TIMING...LIKELY REMAINING MORE SOUTHEAST OR EVEN EAST/
SOUTHEAST NORTH OF THE FRONT WITH SOUTHERLY WINDS SOUTH OF THE
FRONT. CMS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH FOR CIG/VIS TRENDS INTO THIS EVENING.
* MEDIUM FOR CIG/VIS TRENDS OVERNIGHT AND WEDNESDAY MORNING.
* MEDIUM FOR WIND SPEEDS/DIRECTIONS THROUGH THE PERIOD.
* LOW FOR SHOWERS WEDNESDAY MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR POSSIBLE. SLT CHC OF RAIN.
THURSDAY THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW.
MONDAY...MVFR POSSIBLE.
BMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* IFR/LIFR CIGS/VIS LOWERING TO LIFR/VLIFR THIS EVENING/TONIGHT.
* SOUTHEASTERLY WINDS AROUND 10 KT THROUGH EARLY EVENING.
* FOG WITH 1/2SM OVERNIGHT INTO WEDNESDAY MORNING.
* CHANCE OF SHOWERS WEDNESDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE OVER THE SOUTH CENTRAL PLAINS WILL LIFT NORTHEAST
OVER MISSOURI WEDNESDAY MORNING...THEN MOVE NORTHEAST ACROSS
EASTERN IOWA AND NORTHWEST IL EARLY WEDNESDAY AFTERNOON. A WARM
FRONT EXTENDING EAST FROM THIS LOW...CURRENTLY ACROSS CENTRAL IL...
IS EXPECTED TO LIFT NORTH ACROSS THE TERMINALS OVERNIGHT INTO
WEDNESDAY MORNING. HOWEVER...CONFIDENCE REGARDING ITS SPEED AND
LOCATION IS LOW AND THIS CREATES A CHALLENGING FORECAST FOR FOG
POTENTIAL THIS EVENING THROUGH WEDNESDAY MORNING. PREVAILING
VISIBILITIES HAVE REMAINED IN THE 1-2SM WITH RFD NOW SLOWING
APPROACHING 1SM. WITH THE WARM FRONT EXPECTED TO REMAIN SOUTH OF
THE TERMINALS THROUGH AT LEAST THIS EVENING...EXPECT THE VIS TO
LOWER BACK UNDER 1SM THIS EVENING WITH SOME DRIZZLE POSSIBLE. THE
VIS MAY CONTINUE TO LOWER TO 1/2SM OR A 1/4SM AT SOME LOCATIONS...
ESPECIALLY AT RFD. IF THE WARM FRONT IS ABLE TO MOVE ACROSS
NORTHERN IL TONIGHT...VISIBILITIES WILL LIKELY IMPROVE INTO THE
1-2SM RANGE OR BETTER. HOWEVER...ITS POSSIBLE THE FRONT WILL SLOW
OR STALL AND IF THIS OCCURS...VISIBILITIES WILL LIKELY TANK
OVERNIGHT AND PERSIST INTO WEDNESDAY MORNING...WHEN THE WARM FRONT
WILL FINALLY MOVE ACROSS THE AREA.
WIND DIRECTIONS WILL REMAIN SOUTHEASTERLY AROUND 10KTS THIS
AFTERNOON...THEN DIMINISH THIS EVENING. SPECIFIC DIRECTIONS
TONIGHT INTO WEDNESDAY MORNING WILL DEPEND ON THE WARM FRONT
MOVEMENT/TIMING...LIKELY REMAINING MORE SOUTHEAST OR EVEN EAST/
SOUTHEAST NORTH OF THE FRONT WITH SOUTHERLY WINDS SOUTH OF THE
FRONT. CMS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH FOR CIG/VIS TRENDS INTO THIS EVENING.
* MEDIUM FOR CIG/VIS TRENDS OVERNIGHT AND WEDNESDAY MORNING.
* MEDIUM FOR WIND SPEEDS/DIRECTIONS THROUGH THE PERIOD.
* LOW FOR SHOWERS WEDNESDAY MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR POSSIBLE. SLT CHC OF RAIN.
THURSDAY THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW.
MONDAY...MVFR POSSIBLE.
BMD
&&
.MARINE...
228 PM CST
EASTERLY FLOW WILL CONTINUE OVER THE LAKE TONIGHT AND GRADUALLY VEER
TO SOUTH DURING WEDNESDAY. THIS WILL CONTINUE TO BRING ANOMALOUSLY
HIGH MOISTURE FOR THIS TIME OF YEAR OVER WHAT IS COOLER WATER...SO
EXPECTING DENSE FOG TO BLOSSOM THROUGH THIS EVENING AND PERSIST INTO
WEDNESDAY. AS THE LOW PRESSURE LIFTS UP TO LAKE SUPERIOR BY
WEDNESDAY EVENING IT WILL SWING A COLD FRONT ACROSS THE LAKE WHICH
WILL INTRODUCE STOUT COLD AIR ADVECTION. THE STEEPENED LAPSE RATES
AND ENHANCED MIXING WILL BRING A PERIOD OF AT LEAST GALE FORCE GUSTS
TO THE OPEN WATER. THESE ARE MOST FAVORED DURING THE DAY THURSDAY
BUT COULD BEGIN LATE WEDNESDAY NIGHT. THROUGHOUT THAT TIME SMALL
CRAFT ADVISORY CRITERIA SHOULD BE REACHED IN THE ILLINOIS AND
INDIANA NEARSHORE ZONES. THIS PATTERN SHIFT WILL BEGIN A PROLONGED
PERIOD OF WEST TO NORTHWEST FLOW OVER THE LAKE INTO THE WEEKEND AS
THE COLD AIR CONTINUES TO RE-ENFORCE ITSELF.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012 UNTIL 10 AM WEDNESDAY.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ870-
LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM WEDNESDAY.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
216 PM CST TUE DEC 3 2013
.DISCUSSION...
1055 AM CST
HAVE EXTENDED THE DENSE FOG ADVISORY A COUPLE HOURS ACROSS NORTH
CENTRAL IL AS WELL AS EXPAND IT EASTWARD INTO THE FAR WESTERN
CHICAGO SUBURBS. ALSO HAVE BUMPED DOWN HIGH TEMPERATURES SEVERAL
DEGREES GIVEN THE LIMITED WARM ADVECTION NOT BEING ABLE TO OFFSET
NULL SOLAR HEATING.
OBSERVED VISIBILITY AND WEBCAMS ACROSS MUCH OF NORTH CENTRAL AND
NORTHWEST IL INDICATE LITTLE IMPROVEMENT HAS OCCURRED WITH T/TD
SPREADS ALMOST ENTIRELY AT 1F OR LESS. WITH TEMPERATURES STILL
AROUND 40 AND QUITE A WAYS FROM THAT 48-50 NEEDED ON THE 12Z DVN
RAOB TO BREAK THROUGH INTO BETTER MIXING...NOT EXPECTING RAPID
IMPROVEMENT. HIGH RES MODELS AND ENSEMBLES SUCH AS THE HRRR AND
NARRE-TL INDICATE SLIGHT VISIBILITY IMPROVEMENT THIS
AFTERNOON...WHILE ALSO BOTH INDICATING SUSCEPTIBILITY TO DROPPING
RIGHT BACK INTO DENSE FOG AFTER DARK WHICH CONCEPTUALLY MAKES
SENSE WITH THE AREA ALONG/NORTH OF THE WARM FRONT. HOW QUICKLY THE
WARM FRONT PROGRESSES NORTHWARD TONIGHT IS HIGHLY UNCERTAIN AND
SOMETHING MODELS MAY PROGRESS TOO QUICKLY. HAVE FOR THE TIME BEING
ADDED AREAS OF FOG MENTION ACROSS THE CWA.
INTERMITTENT LIGHT RAIN/DRIZZLE SHOULD CONTINUE WITH ANOTHER
SMALL SCALE MID-LEVEL IMPULSE HELPING TO BRING A BIT OF ENHANCED
WARM AIR ADVECTION/ISENTROPIC ASCENT AND JUST SOME BROAD AND WEAK
OMEGA.
TEMPERATURES WILL OOZE UPWARD AND MAY REACH THEIR MAXS TOWARD 4-5
PM...ABOUT 1-2 HRS LATER THAN TYPICAL THIS TIME OF YEAR.
TEMPERATURES SHOULD BASICALLY HOLD STEADY INTO THE EVE AND MAY
CLIMB LATER INTO THE NIGHT.
MTF
//PREV DISCUSSION...
330 AM CST
FORECAST FOCUS REMAINS LARGELY ON THE NEAR TERM THIS MORNING...
NAMELY PRECIPITATION AND TEMPERATURE TRENDS TODAY THROUGH WEDNESDAY
AS DEEP LOW PRESSURE SYSTEM DEVELOPS IN RESPONSE TO AMPLIFICATION OF
UPPER TROUGH ACROSS THE WESTERN/CENTRAL CONUS. DAYS 3-7 CONTINUE TO
FEATURE MUCH COLDER THAN AVERAGE TEMPERATURES...WITH THE POTENTIAL
FOR A COUPLE OF LIGHT SNOW EVENTS MAINLY ACROSS THE FAR SOUTHEAST
LATE THURSDAY-FRIDAY...AND FOR MOST OF THE AREA SUNDAY/SUNDAY NIGHT.
00Z RAOB ANALYSIS INDICATES FAIRLY ZONAL FLOW PATTERN ACROSS THE
CENTRAL CONUS...WITH A DEEP SHORT WAVE TROUGH DIGGING SOUTHEAST
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SEVERAL RELATIVELY MINOR
AMPLITUDE SHORT WAVES WERE NOTED DOWNSTREAM ACROSS THE MIDWEST...
EMANATING FROM STRONG JET STREAK DEVELOPS AROUND THE SOUTHERN
PERIPHERY OF THE DIGGING TROUGH. ONE SUCH WAVE WAS NOTED IN WATER
VAPOR IMAGERY OVER THE UPPER MISSISSIPPI VALLEY EARLY THIS
MORNING...WHICH WAS RESPONSIBLE FOR AN AREA OF WARM ADVECTION
PRECIPITATION THAT MOVED ACROSS THE FORECAST AREA OVERNIGHT AND WAS
NOW EAST OF THE REGION. A COUPLE OF MORE SUBTLE MID-LEVEL WAVES WERE
NOTED IN THE SATELLITE IMAGERY...ONE APPROACHING QUICKLY FROM
EASTERN IA...AND THE OTHER UPSTREAM ACROSS WESTERN NEBRASKA. THESE
FEATURES WILL RIPPLE QUICKLY EAST ACROSS THE AREA TODAY...MAINLY
WORKING TO MAINTAIN SOUTHERLY FLOW AND CONTINUED WARM ADVECTION INTO
THE MIDWEST. WHILE SOME SPOTTY LIGHT RAIN IS POSSIBLE WITH ANY OF
THESE SUBTLE FEATURES...UPSTREAM SOUNDINGS FROM OMA/TOP/SGF INDICATE
FAIRLY DRY MID-LEVELS. FORECAST SOUNDINGS MAINTAIN THIS DRY LAYER
ROUGHLY BETWEEN 850-650 MB WHICH SUGGESTS MAINLY SCATTERED LIGHT
RAIN OR SOME DRIZZLE WITH ONLY LIGHT QPF AMOUNTS TODAY-TONIGHT AS
FORCING WITH THESE WAVES ACT ON MOIST LOW LEVELS OR BRIEF POCKETS OF
ENHANCED MID-LEVEL MOISTURE.
WITH ONGOING WARM ADVECTION...SURFACE TEMPERATURES AND DEW POINTS
WILL CONTINUE TO SLOWLY RISE AS A WARM FRONT CURRENTLY LIFTING INTO
CENTRAL ILLINOIS MOVES NORTH. WHILE THE BOUNDARY REMAINS A BIT
DIFFUSE EARLY THIS MORNING...THE FRONT SHOULD SHARPEN AND BEGIN TO
MOVE FASTER LATER TODAY AND TONIGHT AS SURFACE LOW PRESSURE DEEPENS
TO OUR WEST ACROSS THE CENTRAL PLAINS IN RESPONSE TO HEIGHT FALLS
WITH DEEPENING WESTERN TROUGH. MODELS ARE IN FAIRLY GOOD AGREEMENT
THAT THE SURFACE WARM FRONT SHOULD LIFT INTO NORTHERN IL BY LATE
AFTERNOON...WITH THE SOUTHERN AND CENTRAL PARTS OF THE CWA GETTING
INTO THE WARM SECTOR. TEMPS SHOULD REACH THE LOW-MID 50S ALONG AND
SOUTH OF I-80 THIS AFTERNOON...WITH 40S TO THE NORTH. IT WILL REMAIN
VERY MILD TONIGHT AS THE WARM FRONT REACHES THE IL/WI BORDER...WITH
OVERNIGHT LOWS HOLDING IN THE 40S ACROSS THE CWA.
GUIDANCE REMAINS IN TWO SEPARATE CAMPS WITH THE HANDLING OF THE MAIN
SURFACE LOW AND COLD FRONT ON WEDNESDAY...WITH THE DOMESTIC MODELS
REMAINING FASTER AND INITIALLY DEEPER BEYOND 30 HOURS THAN THE UK/EC
AND CANADIAN COUNTERPARTS. THE 00Z RUNS OF THE GFS AND TO A GREATER
EXTENT THE WRF HAVE SLOWED HOWEVER...WHICH LENDS SUPPORT TO OUR
FAVORING THE SLOWER SOLUTION OF THE UKMET/ECMWF AND GEM. THUS
CONTINUE TO FAVOR THE SCENARIO OF THE SURFACE LOW LIFTING ACROSS
EASTERN IOWA INTO WI WEDNESDAY AFTERNOON...AND THE TRAILING COLD
FRONT MOVING ACROSS THE WFO LOT FORECAST AREA FAIRLY LATE IN THE
AFTERNOON AND EVENING HOURS. THIS SUPPORTS TEMPS IN THE 50S...AND
EVEN A COUPLE OF 60S FAR SOUTH...WEDNESDAY WITH THE CWA STILL IN THE
WARM SECTOR AHEAD OF THE FRONT. MID-LEVEL MOISTURE CONTINUES TO BE
LIMITED...AND ALTHOUGH LIGHT RAIN/SHOWER CHANCES DO INCREASE WITH
THE APPROACH OF THE LOW/COLD FRONT THE BEST COVERAGE AND RAINFALL
AMOUNTS EXPECTED NORTH OF THE AREA ACROSS WI AND THE NORTHERN LAKES.
THE COLD FRONT PUSHES ACROSS THE AREA WEDNESDAY EVENING...SHUTTING
OFF PRECIP AS MID/UPPER LEVELS DRY OUT. THANKS TO WEST-SOUTHWEST
FLOW ALOFT THE FIRST PUSH OF COLDER AIR IS RELATIVELY WEAK...AS THE
FRONT AND LOW LEVEL BAROCLINIC ZONE SLOW UP FROM THE OHIO VALLEY TO
THE EASTERN LAKES INTO THURSDAY. A COUPLE OF DISTURBANCES RIPPLE
NORTHEAST ALONG THIS BAROCLINIC ZONE LATE THURSDAY INTO FRIDAY...
WITH THE POTENTIAL FOR SOME LIGHT SNOW FROM CENTRAL IL INTO NORTHERN
INDIANA AND MAINLY CLIPPING THE FAR SOUTHEAST PART OF THE CWA. A
SECOND PUSH OF COLDER AIR THEN SPREADS IN THURSDAY NIGHT-FRIDAY AS
THE UPPER LOW PASSES TO THE NORTH AND HEADS INTO EASTERN CANADA.
THIS ALLOWS 850 MB AIR OF -10 TO -15 C ACROSS THE AREA AND TEMPS A
GOOD 8-10F COLDER FRIDAY THAN ON THURSDAY. SOME DIFFERENCES REMAIN
WITH MODEL DETAILS AT THIS TIME...BUT CONTINUE TO FAVOR THE SIMILAR
GEM/ECMWF WHICH SUPPORTS HIGHS ONLY NEAR/AROUND 20 FRIDAY AND
SATURDAY AS ARCTIC HIGH PRESSURE BUILDS ACROSS THE MIDWEST. LOOKS
LIKE AT LEAST SOME SLIGHT MODERATION SUNDAY-MONDAY AS UPPER TROUGH
AMPLIFIES ACROSS THE WESTERN CONUS/NOAM...WITH AN AREA OF LOW
PRESSURE LIFTING ACROSS THE AREA SUNDAY WITH THE POTENTIAL FOR SOME
LIGHT SNOW.
RATZER
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* IFR/LIFR CIGS/VIS LOWERING TO LIFR/VLIFR THIS EVENING/TONIGHT.
* SOUTHEASTERLY WINDS AROUND 10 KT THROUGH EARLY EVENING.
* FOG WITH 1/2SM OVERNIGHT INTO WEDNESDAY MORNING.
* CHANCE OF SHOWERS WEDNESDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE OVER THE SOUTH CENTRAL PLAINS WILL LIFT NORTHEAST
OVER MISSOURI WEDNESDAY MORNING...THEN MOVE NORTHEAST ACROSS
EASTERN IOWA AND NORTHWEST IL EARLY WEDNESDAY AFTERNOON. A WARM
FRONT EXTENDING EAST FROM THIS LOW...CURRENTLY ACROSS CENTRAL IL...
IS EXPECTED TO LIFT NORTH ACROSS THE TERMINALS OVERNIGHT INTO
WEDNESDAY MORNING. HOWEVER...CONFIDENCE REGARDING ITS SPEED AND
LOCATION IS LOW AND THIS CREATES A CHALLENGING FORECAST FOR FOG
POTENTIAL THIS EVENING THROUGH WEDNESDAY MORNING. PREVAILING
VISIBILITIES HAVE REMAINED IN THE 1-2SM WITH RFD NOW SLOWING
APPROACHING 1SM. WITH THE WARM FRONT EXPECTED TO REMAIN SOUTH OF
THE TERMINALS THROUGH AT LEAST THIS EVENING...EXPECT THE VIS TO
LOWER BACK UNDER 1SM THIS EVENING WITH SOME DRIZZLE POSSIBLE. THE
VIS MAY CONTINUE TO LOWER TO 1/2SM OR A 1/4SM AT SOME LOCATIONS...
ESPECIALLY AT RFD. IF THE WARM FRONT IS ABLE TO MOVE ACROSS
NORTHERN IL TONIGHT...VISIBILITIES WILL LIKELY IMPROVE INTO THE
1-2SM RANGE OR BETTER. HOWEVER...ITS POSSIBLE THE FRONT WILL SLOW
OR STALL AND IF THIS OCCURS...VISIBILITIES WILL LIKELY TANK
OVERNIGHT AND PERSIST INTO WEDNESDAY MORNING...WHEN THE WARM FRONT
WILL FINALLY MOVE ACROSS THE AREA.
WIND DIRECTIONS WILL REMAIN SOUTHEASTERLY AROUND 10KTS THIS
AFTERNOON...THEN DIMINISH THIS EVENING. SPECIFIC DIRECTIONS
TONIGHT INTO WEDNESDAY MORNING WILL DEPEND ON THE WARM FRONT
MOVEMENT/TIMING...LIKELY REMAINING MORE SOUTHEAST OR EVEN EAST/
SOUTHEAST NORTH OF THE FRONT WITH SOUTHERLY WINDS SOUTH OF THE
FRONT. CMS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH FOR CIG/VIS TRENDS INTO THIS EVENING.
* MEDIUM FOR CIG/VIS TRENDS OVERNIGHT AND WEDNESDAY MORNING.
* MEDIUM FOR WIND SPEEDS/DIRECTIONS THROUGH THE PERIOD.
* LOW FOR SHOWERS WEDNESDAY MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR POSSIBLE. SLT CHC OF RAIN.
THURSDAY THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW.
MONDAY...MVFR POSSIBLE.
BMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* IFR/LIFR CIGS/VIS LOWERING TO LIFR/VLIFR LATE THIS AFTERNOON/
EARLY EVENING.
* CHANCE OF LIGHT RAIN LATE THIS AFTERNOON/EARLY EVENING.
* SOUTHEASTERLY WINDS UP TO 10 KT THROUGH EARLY EVENING.
* FOG WITH 1/2SM OVERNIGHT INTO WEDNESDAY MORNING.
* CHANCE OF SHOWERS WEDNESDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE OVER THE SOUTH CENTRAL PLAINS WILL LIFT NORTHEAST
OVER MISSOURI WEDNESDAY MORNING...THEN MOVE NORTHEAST ACROSS
EASTERN IOWA AND NORTHWEST IL EARLY WEDNESDAY AFTERNOON. A WARM
FRONT EXTENDING EAST FROM THIS LOW...CURRENTLY ACROSS CENTRAL IL...
IS EXPECTED TO LIFT NORTH ACROSS THE TERMINALS OVERNIGHT INTO
WEDNESDAY MORNING. HOWEVER...CONFIDENCE REGARDING ITS SPEED AND
LOCATION IS LOW AND THIS CREATES A CHALLENGING FORECAST FOR FOG
POTENTIAL THIS EVENING THROUGH WEDNESDAY MORNING. PREVAILING
VISIBILITIES HAVE REMAINED IN THE 1-2SM WITH RFD NOW SLOWING
APPROACHING 1SM. WITH THE WARM FRONT EXPECTED TO REMAIN SOUTH OF
THE TERMINALS THROUGH AT LEAST THIS EVENING...EXPECT THE VIS TO
LOWER BACK UNDER 1SM THIS EVENING WITH SOME DRIZZLE POSSIBLE. THE
VIS MAY CONTINUE TO LOWER TO 1/2SM OR A 1/4SM AT SOME LOCATIONS...
ESPECIALLY AT RFD. IF THE WARM FRONT IS ABLE TO MOVE ACROSS
NORTHERN IL TONIGHT...VISIBILITIES WILL LIKELY IMPROVE INTO THE
1-2SM RANGE OR BETTER. HOWEVER...ITS POSSIBLE THE FRONT WILL SLOW
OR STALL AND IF THIS OCCURS...VISIBILITIES WILL LIKELY TANK
OVERNIGHT AND PERSIST INTO WEDNESDAY MORNING...WHEN THE WARM FRONT
WILL FINALLY MOVE ACROSS THE AREA.
WIND DIRECTIONS WILL REMAIN SOUTHEASTERLY AROUND 10KTS THIS
AFTERNOON...THEN DIMINISH THIS EVENING. SPECIFIC DIRECTIONS
TONIGHT INTO WEDNESDAY MORNING WILL DEPEND ON THE WARM FRONT
MOVEMENT/TIMING...LIKELY REMAINING MORE SOUTHEAST OR EVEN EAST/
SOUTHEAST NORTH OF THE FRONT WITH SOUTHERLY WINDS SOUTH OF THE
FRONT. CMS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH FOR CIG/VIS TRENDS INTO THIS EVENING.
* MEDIUM FOR LIGHT RAIN LATE THIS AFTERNOON/EARLY THIS EVENING.
* MEDIUM FOR CIG/VIS TRENDS OVERNIGHT AND WEDNESDAY MORNING.
* MEDIUM FOR WIND SPEEDS/DIRECTIONS THROUGH THE PERIOD.
* LOW FOR SHOWERS WEDNESDAY MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR POSSIBLE. SLT CHC OF RAIN.
THURSDAY THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW.
MONDAY...MVFR POSSIBLE.
BMD
&&
.MARINE...
239 AM CST
STILL SIGNIFICANT DIFFERENCES IN THE MODELS WITH RESPECT TO LOW
PRESSURE THAT IS EXPECTED TO IMPACT THE LAKES MIDWEEK. GUIDANCE HAS
TRENDED TOWARDS A SLOWER FRONTAL TIMING AND MORE NORTHERLY LOW TRACK
THOUGH...A TYPICAL TREND WHEN THE UPPER AIR PATTERN IS AMPLIFIED.
WITH THAT IN MIND...HAVE BASED FORECAST TIMING ON A BLEND OF THE GEM
AND THE ECWMF WHICH HAVE BEEN FAIRLY CONSISTENT WITH SLOWER TIMING
AND WHICH THE FASTER NCEP GUIDANCE SEEMS TO BE TRENDING TOWARDS. A
DEEPENING AREA OF LOW PRESSURE IS EXPECTED TO LIFT FROM THE CENTRAL
PLAINS TODAY AND TOMORROW...ACROSS LAKE SUPERIOR OR WEDNESDAY NIGHT.
MODERATE SOUTHEAST TO EAST WINDS ARE EXPECTED AHEAD OF THE
LOW...THOUGH STABLE CONDITIONS WILL HELP KEEP THE HIGHER END GUSTS
FROM REACHING THE LAKE SURFACE. BEHIND THE FRONT...STRONG AND COLD
HIGH PRESSURE WILL OVERSPREAD THE PLAINS WITH A TIGHT GRADIENT ONLY
VERY GRADUALLY SUBSIDING THROUGH THE REST OF THE WEEK. THERE MAY BE
A SHORT PERIOD OF WESTERLY GALES IMMEDIATELY BEHIND THE FRONT
WEDNESDAY NIGHT INTO THURSDAY...WITH 30KTS REST OF THURSDAY INTO
FRIDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY
IS UNTIL 3 PM TUESDAY.
&&
$$
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
1138 AM CST TUE DEC 3 2013
.DISCUSSION...
1055 AM CST
HAVE EXTENDED THE DENSE FOG ADVISORY A COUPLE HOURS ACROSS NORTH
CENTRAL IL AS WELL AS EXPAND IT EASTWARD INTO THE FAR WESTERN
CHICAGO SUBURBS. ALSO HAVE BUMPED DOWN HIGH TEMPERATURES SEVERAL
DEGREES GIVEN THE LIMITED WARM ADVECTION NOT BEING ABLE TO OFFSET
NULL SOLAR HEATING.
OBSERVED VISIBILITY AND WEBCAMS ACROSS MUCH OF NORTH CENTRAL AND
NORTHWEST IL INDICATE LITTLE IMPROVEMENT HAS OCCURRED WITH T/TD
SPREADS ALMOST ENTIRELY AT 1F OR LESS. WITH TEMPERATURES STILL
AROUND 40 AND QUITE A WAYS FROM THAT 48-50 NEEDED ON THE 12Z DVN
RAOB TO BREAK THROUGH INTO BETTER MIXING...NOT EXPECTING RAPID
IMPROVEMENT. HIGH RES MODELS AND ENSEMBLES SUCH AS THE HRRR AND
NARRE-TL INDICATE SLIGHT VISIBILITY IMPROVEMENT THIS
AFTERNOON...WHILE ALSO BOTH INDICATING SUSCEPTIBILITY TO DROPPING
RIGHT BACK INTO DENSE FOG AFTER DARK WHICH CONCEPTUALLY MAKES
SENSE WITH THE AREA ALONG/NORTH OF THE WARM FRONT. HOW QUICKLY THE
WARM FRONT PROGRESSES NORTHWARD TONIGHT IS HIGHLY UNCERTAIN AND
SOMETHING MODELS MAY PROGRESS TOO QUICKLY. HAVE FOR THE TIME BEING
ADDED AREAS OF FOG MENTION ACROSS THE CWA.
INTERMITTENT LIGHT RAIN/DRIZZLE SHOULD CONTINUE WITH ANOTHER
SMALL SCALE MID-LEVEL IMPULSE HELPING TO BRING A BIT OF ENHANCED
WARM AIR ADVECTION/ISENTROPIC ASCENT AND JUST SOME BROAD AND WEAK
OMEGA.
TEMPERATURES WILL OOZE UPWARD AND MAY REACH THEIR MAXS TOWARD 4-5
PM...ABOUT 1-2 HRS LATER THAN TYPICAL THIS TIME OF YEAR.
TEMPERATURES SHOULD BASICALLY HOLD STEADY INTO THE EVE AND MAY
CLIMB LATER INTO THE NIGHT.
MTF
&&
.PREV DISCUSSION...
330 AM CST
FORECAST FOCUS REMAINS LARGELY ON THE NEAR TERM THIS MORNING...
NAMELY PRECIPITATION AND TEMPERATURE TRENDS TODAY THROUGH WEDNESDAY
AS DEEP LOW PRESSURE SYSTEM DEVELOPS IN RESPONSE TO AMPLIFICATION OF
UPPER TROUGH ACROSS THE WESTERN/CENTRAL CONUS. DAYS 3-7 CONTINUE TO
FEATURE MUCH COLDER THAN AVERAGE TEMPERATURES...WITH THE POTENTIAL
FOR A COUPLE OF LIGHT SNOW EVENTS MAINLY ACROSS THE FAR SOUTHEAST
LATE THURSDAY-FRIDAY...AND FOR MOST OF THE AREA SUNDAY/SUNDAY NIGHT.
00Z RAOB ANALYSIS INDICATES FAIRLY ZONAL FLOW PATTERN ACROSS THE
CENTRAL CONUS...WITH A DEEP SHORT WAVE TROUGH DIGGING SOUTHEAST
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SEVERAL RELATIVELY MINOR
AMPLITUDE SHORT WAVES WERE NOTED DOWNSTREAM ACROSS THE MIDWEST...
EMANATING FROM STRONG JET STREAK DEVELOPS AROUND THE SOUTHERN
PERIPHERY OF THE DIGGING TROUGH. ONE SUCH WAVE WAS NOTED IN WATER
VAPOR IMAGERY OVER THE UPPER MISSISSIPPI VALLEY EARLY THIS
MORNING...WHICH WAS RESPONSIBLE FOR AN AREA OF WARM ADVECTION
PRECIPITATION THAT MOVED ACROSS THE FORECAST AREA OVERNIGHT AND WAS
NOW EAST OF THE REGION. A COUPLE OF MORE SUBTLE MID-LEVEL WAVES WERE
NOTED IN THE SATELLITE IMAGERY...ONE APPROACHING QUICKLY FROM
EASTERN IA...AND THE OTHER UPSTREAM ACROSS WESTERN NEBRASKA. THESE
FEATURES WILL RIPPLE QUICKLY EAST ACROSS THE AREA TODAY...MAINLY
WORKING TO MAINTAIN SOUTHERLY FLOW AND CONTINUED WARM ADVECTION INTO
THE MIDWEST. WHILE SOME SPOTTY LIGHT RAIN IS POSSIBLE WITH ANY OF
THESE SUBTLE FEATURES...UPSTREAM SOUNDINGS FROM OMA/TOP/SGF INDICATE
FAIRLY DRY MID-LEVELS. FORECAST SOUNDINGS MAINTAIN THIS DRY LAYER
ROUGHLY BETWEEN 850-650 MB WHICH SUGGESTS MAINLY SCATTERED LIGHT
RAIN OR SOME DRIZZLE WITH ONLY LIGHT QPF AMOUNTS TODAY-TONIGHT AS
FORCING WITH THESE WAVES ACT ON MOIST LOW LEVELS OR BRIEF POCKETS OF
ENHANCED MID-LEVEL MOISTURE.
WITH ONGOING WARM ADVECTION...SURFACE TEMPERATURES AND DEW POINTS
WILL CONTINUE TO SLOWLY RISE AS A WARM FRONT CURRENTLY LIFTING INTO
CENTRAL ILLINOIS MOVES NORTH. WHILE THE BOUNDARY REMAINS A BIT
DIFFUSE EARLY THIS MORNING...THE FRONT SHOULD SHARPEN AND BEGIN TO
MOVE FASTER LATER TODAY AND TONIGHT AS SURFACE LOW PRESSURE DEEPENS
TO OUR WEST ACROSS THE CENTRAL PLAINS IN RESPONSE TO HEIGHT FALLS
WITH DEEPENING WESTERN TROUGH. MODELS ARE IN FAIRLY GOOD AGREEMENT
THAT THE SURFACE WARM FRONT SHOULD LIFT INTO NORTHERN IL BY LATE
AFTERNOON...WITH THE SOUTHERN AND CENTRAL PARTS OF THE CWA GETTING
INTO THE WARM SECTOR. TEMPS SHOULD REACH THE LOW-MID 50S ALONG AND
SOUTH OF I-80 THIS AFTERNOON...WITH 40S TO THE NORTH. IT WILL REMAIN
VERY MILD TONIGHT AS THE WARM FRONT REACHES THE IL/WI BORDER...WITH
OVERNIGHT LOWS HOLDING IN THE 40S ACROSS THE CWA.
GUIDANCE REMAINS IN TWO SEPARATE CAMPS WITH THE HANDLING OF THE MAIN
SURFACE LOW AND COLD FRONT ON WEDNESDAY...WITH THE DOMESTIC MODELS
REMAINING FASTER AND INITIALLY DEEPER BEYOND 30 HOURS THAN THE UK/EC
AND CANADIAN COUNTERPARTS. THE 00Z RUNS OF THE GFS AND TO A GREATER
EXTENT THE WRF HAVE SLOWED HOWEVER...WHICH LENDS SUPPORT TO OUR
FAVORING THE SLOWER SOLUTION OF THE UKMET/ECMWF AND GEM. THUS
CONTINUE TO FAVOR THE SCENARIO OF THE SURFACE LOW LIFTING ACROSS
EASTERN IOWA INTO WI WEDNESDAY AFTERNOON...AND THE TRAILING COLD
FRONT MOVING ACROSS THE WFO LOT FORECAST AREA FAIRLY LATE IN THE
AFTERNOON AND EVENING HOURS. THIS SUPPORTS TEMPS IN THE 50S...AND
EVEN A COUPLE OF 60S FAR SOUTH...WEDNESDAY WITH THE CWA STILL IN THE
WARM SECTOR AHEAD OF THE FRONT. MID-LEVEL MOISTURE CONTINUES TO BE
LIMITED...AND ALTHOUGH LIGHT RAIN/SHOWER CHANCES DO INCREASE WITH
THE APPROACH OF THE LOW/COLD FRONT THE BEST COVERAGE AND RAINFALL
AMOUNTS EXPECTED NORTH OF THE AREA ACROSS WI AND THE NORTHERN LAKES.
THE COLD FRONT PUSHES ACROSS THE AREA WEDNESDAY EVENING...SHUTTING
OFF PRECIP AS MID/UPPER LEVELS DRY OUT. THANKS TO WEST-SOUTHWEST
FLOW ALOFT THE FIRST PUSH OF COLDER AIR IS RELATIVELY WEAK...AS THE
FRONT AND LOW LEVEL BAROCLINIC ZONE SLOW UP FROM THE OHIO VALLEY TO
THE EASTERN LAKES INTO THURSDAY. A COUPLE OF DISTURBANCES RIPPLE
NORTHEAST ALONG THIS BAROCLINIC ZONE LATE THURSDAY INTO FRIDAY...
WITH THE POTENTIAL FOR SOME LIGHT SNOW FROM CENTRAL IL INTO NORTHERN
INDIANA AND MAINLY CLIPPING THE FAR SOUTHEAST PART OF THE CWA. A
SECOND PUSH OF COLDER AIR THEN SPREADS IN THURSDAY NIGHT-FRIDAY AS
THE UPPER LOW PASSES TO THE NORTH AND HEADS INTO EASTERN CANADA.
THIS ALLOWS 850 MB AIR OF -10 TO -15 C ACROSS THE AREA AND TEMPS A
GOOD 8-10F COLDER FRIDAY THAN ON THURSDAY. SOME DIFFERENCES REMAIN
WITH MODEL DETAILS AT THIS TIME...BUT CONTINUE TO FAVOR THE SIMILAR
GEM/ECMWF WHICH SUPPORTS HIGHS ONLY NEAR/AROUND 20 FRIDAY AND
SATURDAY AS ARCTIC HIGH PRESSURE BUILDS ACROSS THE MIDWEST. LOOKS
LIKE AT LEAST SOME SLIGHT MODERATION SUNDAY-MONDAY AS UPPER TROUGH
AMPLIFIES ACROSS THE WESTERN CONUS/NOAM...WITH AN AREA OF LOW
PRESSURE LIFTING ACROSS THE AREA SUNDAY WITH THE POTENTIAL FOR SOME
LIGHT SNOW.
RATZER
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* IFR/LIFR CIGS/VIS LOWERING TO LIFR/VLIFR THIS EVENING/TONIGHT.
* SOUTHEASTERLY WINDS AROUND 10 KT THROUGH EARLY EVENING.
* FOG WITH 1/2SM OVERNIGHT INTO WEDNESDAY MORNING.
* CHANCE OF SHOWERS WEDNESDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE OVER THE SOUTH CENTRAL PLAINS WILL LIFT NORTHEAST
OVER MISSOURI WEDNESDAY MORNING...THEN MOVE NORTHEAST ACROSS
EASTERN IOWA AND NORTHWEST IL EARLY WEDNESDAY AFTERNOON. A WARM
FRONT EXTENDING EAST FROM THIS LOW...CURRENTLY ACROSS CENTRAL IL...
IS EXPECTED TO LIFT NORTH ACROSS THE TERMINALS OVERNIGHT INTO
WEDNESDAY MORNING. HOWEVER...CONFIDENCE REGARDING ITS SPEED AND
LOCATION IS LOW AND THIS CREATES A CHALLENGING FORECAST FOR FOG
POTENTIAL THIS EVENING THROUGH WEDNESDAY MORNING. PREVAILING
VISIBILITIES HAVE REMAINED IN THE 1-2SM WITH RFD NOW SLOWING
APPROACHING 1SM. WITH THE WARM FRONT EXPECTED TO REMAIN SOUTH OF
THE TERMINALS THROUGH AT LEAST THIS EVENING...EXPECT THE VIS TO
LOWER BACK UNDER 1SM THIS EVENING WITH SOME DRIZZLE POSSIBLE. THE
VIS MAY CONTINUE TO LOWER TO 1/2SM OR A 1/4SM AT SOME LOCATIONS...
ESPECIALLY AT RFD. IF THE WARM FRONT IS ABLE TO MOVE ACROSS
NORTHERN IL TONIGHT...VISIBILITIES WILL LIKELY IMPROVE INTO THE
1-2SM RANGE OR BETTER. HOWEVER...ITS POSSIBLE THE FRONT WILL SLOW
OR STALL AND IF THIS OCCURS...VISIBILITIES WILL LIKELY TANK
OVERNIGHT AND PERSIST INTO WEDNESDAY MORNING...WHEN THE WARM FRONT
WILL FINALLY MOVE ACROSS THE AREA.
WIND DIRECTIONS WILL REMAIN SOUTHEASTERLY AROUND 10KTS THIS
AFTERNOON...THEN DIMINISH THIS EVENING. SPECIFIC DIRECTIONS
TONIGHT INTO WEDNESDAY MORNING WILL DEPEND ON THE WARM FRONT
MOVEMENT/TIMING...LIKELY REMAINING MORE SOUTHEAST OR EVEN EAST/
SOUTHEAST NORTH OF THE FRONT WITH SOUTHERLY WINDS SOUTH OF THE
FRONT. CMS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH FOR CIG/VIS TRENDS INTO THIS EVENING.
* MEDIUM FOR CIG/VIS TRENDS OVERNIGHT AND WEDNESDAY MORNING.
* MEDIUM FOR WIND SPEEDS/DIRECTIONS THROUGH THE PERIOD.
* LOW FOR SHOWERS WEDNESDAY MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR POSSIBLE. SLT CHC OF RAIN.
THURSDAY THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW.
MONDAY...MVFR POSSIBLE.
BMD
&&
.MARINE...
239 AM CST
STILL SIGNIFICANT DIFFERENCES IN THE MODELS WITH RESPECT TO LOW
PRESSURE THAT IS EXPECTED TO IMPACT THE LAKES MIDWEEK. GUIDANCE HAS
TRENDED TOWARDS A SLOWER FRONTAL TIMING AND MORE NORTHERLY LOW TRACK
THOUGH...A TYPICAL TREND WHEN THE UPPER AIR PATTERN IS AMPLIFIED.
WITH THAT IN MIND...HAVE BASED FORECAST TIMING ON A BLEND OF THE GEM
AND THE ECWMF WHICH HAVE BEEN FAIRLY CONSISTENT WITH SLOWER TIMING
AND WHICH THE FASTER NCEP GUIDANCE SEEMS TO BE TRENDING TOWARDS. A
DEEPENING AREA OF LOW PRESSURE IS EXPECTED TO LIFT FROM THE CENTRAL
PLAINS TODAY AND TOMORROW...ACROSS LAKE SUPERIOR OR WEDNESDAY NIGHT.
MODERATE SOUTHEAST TO EAST WINDS ARE EXPECTED AHEAD OF THE
LOW...THOUGH STABLE CONDITIONS WILL HELP KEEP THE HIGHER END GUSTS
FROM REACHING THE LAKE SURFACE. BEHIND THE FRONT...STRONG AND COLD
HIGH PRESSURE WILL OVERSPREAD THE PLAINS WITH A TIGHT GRADIENT ONLY
VERY GRADUALLY SUBSIDING THROUGH THE REST OF THE WEEK. THERE MAY BE
A SHORT PERIOD OF WESTERLY GALES IMMEDIATELY BEHIND THE FRONT
WEDNESDAY NIGHT INTO THURSDAY...WITH 30KTS REST OF THURSDAY INTO
FRIDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ019-ILZ020-ILZ021-ILZ032 UNTIL 1 PM TUESDAY.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY
IS UNTIL 3 PM TUESDAY.
&&
$$
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...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1055 AM CST TUE DEC 3 2013
.DISCUSSION...
1055 AM CST
HAVE EXTENDED THE DENSE FOG ADVISORY A COUPLE HOURS ACROSS NORTH
CENTRAL IL AS WELL AS EXPAND IT EASTWARD INTO THE FAR WESTERN
CHICAGO SUBURBS. ALSO HAVE BUMPED DOWN HIGH TEMPERATURES SEVERAL
DEGREES GIVEN THE LIMITED WARM ADVECTION NOT BEING ABLE TO OFFSET
NULL SOLAR HEATING.
OBSERVED VISIBILITY AND WEBCAMS ACROSS MUCH OF NORTH CENTRAL AND
NORTHWEST IL INDICATE LITTLE IMPROVEMENT HAS OCCURRED WITH T/TD
SPREADS ALMOST ENTIRELY AT 1F OR LESS. WITH TEMPERATURES STILL
AROUND 40 AND QUITE A WAYS FROM THAT 48-50 NEEDED ON THE 12Z DVN
RAOB TO BREAK THROUGH INTO BETTER MIXING...NOT EXPECTING RAPID
IMPROVEMENT. HIGH RES MODELS AND ENSEMBLES SUCH AS THE HRRR AND
NARRE-TL INDICATE SLIGHT VISIBILITY IMPROVEMENT THIS
AFTERNOON...WHILE ALSO BOTH INDICATING SUSCEPTIBILITY TO DROPPING
RIGHT BACK INTO DENSE FOG AFTER DARK WHICH CONCEPTUALLY MAKES
SENSE WITH THE AREA ALONG/NORTH OF THE WARM FRONT. HOW QUICKLY THE
WARM FRONT PROGRESSES NORTHWARD TONIGHT IS HIGHLY UNCERTAIN AND
SOMETHING MODELS MAY PROGRESS TOO QUICKLY. HAVE FOR THE TIME BEING
ADDED AREAS OF FOG MENTION ACROSS THE CWA.
INTERMITTENT LIGHT RAIN/DRIZZLE SHOULD CONTINUE WITH ANOTHER
SMALL SCALE MID-LEVEL IMPULSE HELPING TO BRING A BIT OF ENHANCED
WARM AIR ADVECTION/ISENTROPIC ASCENT AND JUST SOME BROAD AND WEAK
OMEGA.
TEMPERATURES WILL OOZE UPWARD AND MAY REACH THEIR MAXS TOWARD 4-5
PM...ABOUT 1-2 HRS LATER THAN TYPICAL THIS TIME OF YEAR.
TEMPERATURES SHOULD BASICALLY HOLD STEADY INTO THE EVE AND MAY
CLIMB LATER INTO THE NIGHT.
MTF
&&
//PREV DISCUSSION...
330 AM CST
FORECAST FOCUS REMAINS LARGELY ON THE NEAR TERM THIS MORNING...
NAMELY PRECIPITATION AND TEMPERATURE TRENDS TODAY THROUGH WEDNESDAY
AS DEEP LOW PRESSURE SYSTEM DEVELOPS IN RESPONSE TO AMPLIFICATION OF
UPPER TROUGH ACROSS THE WESTERN/CENTRAL CONUS. DAYS 3-7 CONTINUE TO
FEATURE MUCH COLDER THAN AVERAGE TEMPERATURES...WITH THE POTENTIAL
FOR A COUPLE OF LIGHT SNOW EVENTS MAINLY ACROSS THE FAR SOUTHEAST
LATE THURSDAY-FRIDAY...AND FOR MOST OF THE AREA SUNDAY/SUNDAY NIGHT.
00Z RAOB ANALYSIS INDICATES FAIRLY ZONAL FLOW PATTERN ACROSS THE
CENTRAL CONUS...WITH A DEEP SHORT WAVE TROUGH DIGGING SOUTHEAST
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SEVERAL RELATIVELY MINOR
AMPLITUDE SHORT WAVES WERE NOTED DOWNSTREAM ACROSS THE MIDWEST...
EMANATING FROM STRONG JET STREAK DEVELOPS AROUND THE SOUTHERN
PERIPHERY OF THE DIGGING TROUGH. ONE SUCH WAVE WAS NOTED IN WATER
VAPOR IMAGERY OVER THE UPPER MISSISSIPPI VALLEY EARLY THIS
MORNING...WHICH WAS RESPONSIBLE FOR AN AREA OF WARM ADVECTION
PRECIPITATION THAT MOVED ACROSS THE FORECAST AREA OVERNIGHT AND WAS
NOW EAST OF THE REGION. A COUPLE OF MORE SUBTLE MID-LEVEL WAVES WERE
NOTED IN THE SATELLITE IMAGERY...ONE APPROACHING QUICKLY FROM
EASTERN IA...AND THE OTHER UPSTREAM ACROSS WESTERN NEBRASKA. THESE
FEATURES WILL RIPPLE QUICKLY EAST ACROSS THE AREA TODAY...MAINLY
WORKING TO MAINTAIN SOUTHERLY FLOW AND CONTINUED WARM ADVECTION INTO
THE MIDWEST. WHILE SOME SPOTTY LIGHT RAIN IS POSSIBLE WITH ANY OF
THESE SUBTLE FEATURES...UPSTREAM SOUNDINGS FROM OMA/TOP/SGF INDICATE
FAIRLY DRY MID-LEVELS. FORECAST SOUNDINGS MAINTAIN THIS DRY LAYER
ROUGHLY BETWEEN 850-650 MB WHICH SUGGESTS MAINLY SCATTERED LIGHT
RAIN OR SOME DRIZZLE WITH ONLY LIGHT QPF AMOUNTS TODAY-TONIGHT AS
FORCING WITH THESE WAVES ACT ON MOIST LOW LEVELS OR BRIEF POCKETS OF
ENHANCED MID-LEVEL MOISTURE.
WITH ONGOING WARM ADVECTION...SURFACE TEMPERATURES AND DEW POINTS
WILL CONTINUE TO SLOWLY RISE AS A WARM FRONT CURRENTLY LIFTING INTO
CENTRAL ILLINOIS MOVES NORTH. WHILE THE BOUNDARY REMAINS A BIT
DIFFUSE EARLY THIS MORNING...THE FRONT SHOULD SHARPEN AND BEGIN TO
MOVE FASTER LATER TODAY AND TONIGHT AS SURFACE LOW PRESSURE DEEPENS
TO OUR WEST ACROSS THE CENTRAL PLAINS IN RESPONSE TO HEIGHT FALLS
WITH DEEPENING WESTERN TROUGH. MODELS ARE IN FAIRLY GOOD AGREEMENT
THAT THE SURFACE WARM FRONT SHOULD LIFT INTO NORTHERN IL BY LATE
AFTERNOON...WITH THE SOUTHERN AND CENTRAL PARTS OF THE CWA GETTING
INTO THE WARM SECTOR. TEMPS SHOULD REACH THE LOW-MID 50S ALONG AND
SOUTH OF I-80 THIS AFTERNOON...WITH 40S TO THE NORTH. IT WILL REMAIN
VERY MILD TONIGHT AS THE WARM FRONT REACHES THE IL/WI BORDER...WITH
OVERNIGHT LOWS HOLDING IN THE 40S ACROSS THE CWA.
GUIDANCE REMAINS IN TWO SEPARATE CAMPS WITH THE HANDLING OF THE MAIN
SURFACE LOW AND COLD FRONT ON WEDNESDAY...WITH THE DOMESTIC MODELS
REMAINING FASTER AND INITIALLY DEEPER BEYOND 30 HOURS THAN THE UK/EC
AND CANADIAN COUNTERPARTS. THE 00Z RUNS OF THE GFS AND TO A GREATER
EXTENT THE WRF HAVE SLOWED HOWEVER...WHICH LENDS SUPPORT TO OUR
FAVORING THE SLOWER SOLUTION OF THE UKMET/ECMWF AND GEM. THUS
CONTINUE TO FAVOR THE SCENARIO OF THE SURFACE LOW LIFTING ACROSS
EASTERN IOWA INTO WI WEDNESDAY AFTERNOON...AND THE TRAILING COLD
FRONT MOVING ACROSS THE WFO LOT FORECAST AREA FAIRLY LATE IN THE
AFTERNOON AND EVENING HOURS. THIS SUPPORTS TEMPS IN THE 50S...AND
EVEN A COUPLE OF 60S FAR SOUTH...WEDNESDAY WITH THE CWA STILL IN THE
WARM SECTOR AHEAD OF THE FRONT. MID-LEVEL MOISTURE CONTINUES TO BE
LIMITED...AND ALTHOUGH LIGHT RAIN/SHOWER CHANCES DO INCREASE WITH
THE APPROACH OF THE LOW/COLD FRONT THE BEST COVERAGE AND RAINFALL
AMOUNTS EXPECTED NORTH OF THE AREA ACROSS WI AND THE NORTHERN LAKES.
THE COLD FRONT PUSHES ACROSS THE AREA WEDNESDAY EVENING...SHUTTING
OFF PRECIP AS MID/UPPER LEVELS DRY OUT. THANKS TO WEST-SOUTHWEST
FLOW ALOFT THE FIRST PUSH OF COLDER AIR IS RELATIVELY WEAK...AS THE
FRONT AND LOW LEVEL BAROCLINIC ZONE SLOW UP FROM THE OHIO VALLEY TO
THE EASTERN LAKES INTO THURSDAY. A COUPLE OF DISTURBANCES RIPPLE
NORTHEAST ALONG THIS BAROCLINIC ZONE LATE THURSDAY INTO FRIDAY...
WITH THE POTENTIAL FOR SOME LIGHT SNOW FROM CENTRAL IL INTO NORTHERN
INDIANA AND MAINLY CLIPPING THE FAR SOUTHEAST PART OF THE CWA. A
SECOND PUSH OF COLDER AIR THEN SPREADS IN THURSDAY NIGHT-FRIDAY AS
THE UPPER LOW PASSES TO THE NORTH AND HEADS INTO EASTERN CANADA.
THIS ALLOWS 850 MB AIR OF -10 TO -15 C ACROSS THE AREA AND TEMPS A
GOOD 8-10F COLDER FRIDAY THAN ON THURSDAY. SOME DIFFERENCES REMAIN
WITH MODEL DETAILS AT THIS TIME...BUT CONTINUE TO FAVOR THE SIMILAR
GEM/ECMWF WHICH SUPPORTS HIGHS ONLY NEAR/AROUND 20 FRIDAY AND
SATURDAY AS ARCTIC HIGH PRESSURE BUILDS ACROSS THE MIDWEST. LOOKS
LIKE AT LEAST SOME SLIGHT MODERATION SUNDAY-MONDAY AS UPPER TROUGH
AMPLIFIES ACROSS THE WESTERN CONUS/NOAM...WITH AN AREA OF LOW
PRESSURE LIFTING ACROSS THE AREA SUNDAY WITH THE POTENTIAL FOR SOME
LIGHT SNOW.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* IFR/LIFR CIGS THROUGH WEDNESDAY MORNING.
* CHANCE OF SHOWERS THIS MORNING.
* SOUTHEAST WINDS APPROACHING 10KTS...TURNING MORE SOUTHERLY THIS
AFTERNOON.
* POTENTIAL FOR DENSE FOG TONIGHT/WEDNESDAY MORNING. CMS
//DISCUSSION...UPDATED 14Z...
CIGS/VIS CONTINUE TO TANK ACROSS NORTHWEST AND NORTH CENTRAL IL
THIS MORNING WITH RFD...AND SEVERAL OTHER SITES...AT 1/4SM. THIS
TREND WILL CONTINUE EAST INTO THE CHICAGO AREA TERMINALS WITH
PREVAILING VIS DROPPING INTO THE 1-2SM RANGE...POSSIBLY LOWER AT
DPA. CMS
PREVIOUS 12Z DISCUSSION...
TRICKY FORECAST ON TAP TODAY...WITH IFR CONDITIONS EXPECTED MUCH OF
THE TAF PERIOD. AN ILL-DEFINED WARM FRONTAL BOUNDARY IS DRAPED
ACROSS CENTRAL ILLINOIS AND IS EXPECTED TO GRADUALLY LIFT NORTH
ACROSS THE TERMINALS TODAY. AHEAD OF THE FRONT...IFR CIGS...FOG AND
LIGHT DRIZZLE/RAIN ARE ALL A LIKELIHOOD. WINDS WILL BE OUT OF THE
SE/SSE THROUGH MUCH OF THE DAY...AND MAY VEER BRIEFLY LATE THIS
AFTERNOON AS THE FRONTAL BOUNDARY MAKES IT NEAR THE STATE LINE
BEFORE WASHING OUT. GUIDANCE NOT IN THE BEST AGREEMENT ON WIND
DIRECTION...WITH SOME SUGGESTING WE MAY GO SSW...WHILE MOST KEEP
WIND DIRECTION SSE. ALSO...NAM GUIDANCE SUGGESTS THAT CIGS MAY
BRIEFLY SCATTER OUT SOUTH OF THE FRONT...BUT CONFIDENCE IN THIS
HAPPENING IS TOO LOW TO INCLUDE IN THE TAF AS DEEPENING AREA OF LOW
PRESSURE OVER THE PLAINS WILL BASICALLY CAUSE THE WARM FRONT TO
REORGANIZE BACK TO OUR SOUTH LATE THIS EVENING. THIS BETTER DEFINED
FRONT WILL GRADUALLY LIFT NORTH TOWARDS THE AREA TONIGHT WITH CIGS
EXPECTED TO ONCE AGAIN LOWER AND LIGHT DRIZZLE DEVELOP. THERE IS A
GOOD POSSIBILITY OF DENSE FOG DEVELOPING TONIGHT AS THE FRONTAL
TROUGH NEARS...SIMILAR TO WHAT HAPPENED ACROSS MUCH OF THE MID AND
LOWER MISSISSIPPI VALLEY THIS MORNING. MET/LAV GUIDANCE HITTING THIS
THE HARDEST...BUT FOR NOW WILL STICK WITH MAV/S MORE CONSERVATIVE
FORECAST.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH FOR VIS/CIGS THROUGH THIS AFTERNOON...MEDIUM THIS EVENING
THROUGH WEDNESDAY MORNING.
* MEDIUM SHOWERS WILL STAY NORTH OF ORD/MDW THIS MORNING.
* MEDIUM FOR WIND SPEEDS/DIRECTIONS THROUGH THE PERIOD.
* LOW FOR DENSE FOG TONIGHT/WEDNESDAY MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR POSSIBLE. SLT CHC OF RAIN.
THURSDAY THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW.
MONDAY...MVFR POSSIBLE.
BMD
&&
.MARINE...
239 AM CST
STILL SIGNIFICANT DIFFERENCES IN THE MODELS WITH RESPECT TO LOW
PRESSURE THAT IS EXPECTED TO IMPACT THE LAKES MIDWEEK. GUIDANCE HAS
TRENDED TOWARDS A SLOWER FRONTAL TIMING AND MORE NORTHERLY LOW TRACK
THOUGH...A TYPICAL TREND WHEN THE UPPER AIR PATTERN IS AMPLIFIED.
WITH THAT IN MIND...HAVE BASED FORECAST TIMING ON A BLEND OF THE GEM
AND THE ECWMF WHICH HAVE BEEN FAIRLY CONSISTENT WITH SLOWER TIMING
AND WHICH THE FASTER NCEP GUIDANCE SEEMS TO BE TRENDING TOWARDS. A
DEEPENING AREA OF LOW PRESSURE IS EXPECTED TO LIFT FROM THE CENTRAL
PLAINS TODAY AND TOMORROW...ACROSS LAKE SUPERIOR OR WEDNESDAY NIGHT.
MODERATE SOUTHEAST TO EAST WINDS ARE EXPECTED AHEAD OF THE
LOW...THOUGH STABLE CONDITIONS WILL HELP KEEP THE HIGHER END GUSTS
FROM REACHING THE LAKE SURFACE. BEHIND THE FRONT...STRONG AND COLD
HIGH PRESSURE WILL OVERSPREAD THE PLAINS WITH A TIGHT GRADIENT ONLY
VERY GRADUALLY SUBSIDING THROUGH THE REST OF THE WEEK. THERE MAY BE
A SHORT PERIOD OF WESTERLY GALES IMMEDIATELY BEHIND THE FRONT
WEDNESDAY NIGHT INTO THURSDAY...WITH 30KTS REST OF THURSDAY INTO
FRIDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ019-ILZ020-ILZ021-ILZ032 UNTIL 1 PM TUESDAY.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 3 PM TUESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
549 AM CST TUE DEC 3 2013
.DISCUSSION...
330 AM CST
FORECAST FOCUS REMAINS LARGELY ON THE NEAR TERM THIS MORNING...
NAMELY PRECIPITATION AND TEMPERATURE TRENDS TODAY THROUGH WEDNESDAY
AS DEEP LOW PRESSURE SYSTEM DEVELOPS IN RESPONSE TO AMPLIFICATION OF
UPPER TROUGH ACROSS THE WESTERN/CENTRAL CONUS. DAYS 3-7 CONTINUE TO
FEATURE MUCH COLDER THAN AVERAGE TEMPERATURES...WITH THE POTENTIAL
FOR A COUPLE OF LIGHT SNOW EVENTS MAINLY ACROSS THE FAR SOUTHEAST
LATE THURSDAY-FRIDAY...AND FOR MOST OF THE AREA SUNDAY/SUNDAY NIGHT.
00Z RAOB ANALYSIS INDICATES FAIRLY ZONAL FLOW PATTERN ACROSS THE
CENTRAL CONUS...WITH A DEEP SHORT WAVE TROUGH DIGGING SOUTHEAST
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SEVERAL RELATIVELY MINOR
AMPLITUDE SHORT WAVES WERE NOTED DOWNSTREAM ACROSS THE MIDWEST...
EMANATING FROM STRONG JET STREAK DEVELOPS AROUND THE SOUTHERN
PERIPHERY OF THE DIGGING TROUGH. ONE SUCH WAVE WAS NOTED IN WATER
VAPOR IMAGERY OVER THE UPPER MISSISSIPPI VALLEY EARLY THIS
MORNING...WHICH WAS RESPONSIBLE FOR AN AREA OF WARM ADVECTION
PRECIPITATION THAT MOVED ACROSS THE FORECAST AREA OVERNIGHT AND WAS
NOW EAST OF THE REGION. A COUPLE OF MORE SUBTLE MID-LEVEL WAVES WERE
NOTED IN THE SATELLITE IMAGERY...ONE APPROACHING QUICKLY FROM
EASTERN IA...AND THE OTHER UPSTREAM ACROSS WESTERN NEBRASKA. THESE
FEATURES WILL RIPPLE QUICKLY EAST ACROSS THE AREA TODAY...MAINLY
WORKING TO MAINTAIN SOUTHERLY FLOW AND CONTINUED WARM ADVECTION INTO
THE MIDWEST. WHILE SOME SPOTTY LIGHT RAIN IS POSSIBLE WITH ANY OF
THESE SUBTLE FEATURES...UPSTREAM SOUNDINGS FROM OMA/TOP/SGF INDICATE
FAIRLY DRY MID-LEVELS. FORECAST SOUNDINGS MAINTAIN THIS DRY LAYER
ROUGHLY BETWEEN 850-650 MB WHICH SUGGESTS MAINLY SCATTERED LIGHT
RAIN OR SOME DRIZZLE WITH ONLY LIGHT QPF AMOUNTS TODAY-TONIGHT AS
FORCING WITH THESE WAVES ACT ON MOIST LOW LEVELS OR BRIEF POCKETS OF
ENHANCED MID-LEVEL MOISTURE.
WITH ONGOING WARM ADVECTION...SURFACE TEMPERATURES AND DEW POINTS
WILL CONTINUE TO SLOWLY RISE AS A WARM FRONT CURRENTLY LIFTING INTO
CENTRAL ILLINOIS MOVES NORTH. WHILE THE BOUNDARY REMAINS A BIT
DIFFUSE EARLY THIS MORNING...THE FRONT SHOULD SHARPEN AND BEGIN TO
MOVE FASTER LATER TODAY AND TONIGHT AS SURFACE LOW PRESSURE DEEPENS
TO OUR WEST ACROSS THE CENTRAL PLAINS IN RESPONSE TO HEIGHT FALLS
WITH DEEPENING WESTERN TROUGH. MODELS ARE IN FAIRLY GOOD AGREEMENT
THAT THE SURFACE WARM FRONT SHOULD LIFT INTO NORTHERN IL BY LATE
AFTERNOON...WITH THE SOUTHERN AND CENTRAL PARTS OF THE CWA GETTING
INTO THE WARM SECTOR. TEMPS SHOULD REACH THE LOW-MID 50S ALONG AND
SOUTH OF I-80 THIS AFTERNOON...WITH 40S TO THE NORTH. IT WILL REMAIN
VERY MILD TONIGHT AS THE WARM FRONT REACHES THE IL/WI BORDER...WITH
OVERNIGHT LOWS HOLDING IN THE 40S ACROSS THE CWA.
GUIDANCE REMAINS IN TWO SEPARATE CAMPS WITH THE HANDLING OF THE MAIN
SURFACE LOW AND COLD FRONT ON WEDNESDAY...WITH THE DOMESTIC MODELS
REMAINING FASTER AND INITIALLY DEEPER BEYOND 30 HOURS THAN THE UK/EC
AND CANADIAN COUNTERPARTS. THE 00Z RUNS OF THE GFS AND TO A GREATER
EXTENT THE WRF HAVE SLOWED HOWEVER...WHICH LENDS SUPPORT TO OUR
FAVORING THE SLOWER SOLUTION OF THE UKMET/ECMWF AND GEM. THUS
CONTINUE TO FAVOR THE SCENARIO OF THE SURFACE LOW LIFTING ACROSS
EASTERN IOWA INTO WI WEDNESDAY AFTERNOON...AND THE TRAILING COLD
FRONT MOVING ACROSS THE WFO LOT FORECAST AREA FAIRLY LATE IN THE
AFTERNOON AND EVENING HOURS. THIS SUPPORTS TEMPS IN THE 50S...AND
EVEN A COUPLE OF 60S FAR SOUTH...WEDNESDAY WITH THE CWA STILL IN THE
WARM SECTOR AHEAD OF THE FRONT. MID-LEVEL MOISTURE CONTINUES TO BE
LIMITED...AND ALTHOUGH LIGHT RAIN/SHOWER CHANCES DO INCREASE WITH
THE APPROACH OF THE LOW/COLD FRONT THE BEST COVERAGE AND RAINFALL
AMOUNTS EXPECTED NORTH OF THE AREA ACROSS WI AND THE NORTHERN LAKES.
THE COLD FRONT PUSHES ACROSS THE AREA WEDNESDAY EVENING...SHUTTING
OFF PRECIP AS MID/UPPER LEVELS DRY OUT. THANKS TO WEST-SOUTHWEST
FLOW ALOFT THE FIRST PUSH OF COLDER AIR IS RELATIVELY WEAK...AS THE
FRONT AND LOW LEVEL BAROCLINIC ZONE SLOW UP FROM THE OHIO VALLEY TO
THE EASTERN LAKES INTO THURSDAY. A COUPLE OF DISTURBANCES RIPPLE
NORTHEAST ALONG THIS BAROCLINIC ZONE LATE THURSDAY INTO FRIDAY...
WITH THE POTENTIAL FOR SOME LIGHT SNOW FROM CENTRAL IL INTO NORTHERN
INDIANA AND MAINLY CLIPPING THE FAR SOUTHEAST PART OF THE CWA. A
SECOND PUSH OF COLDER AIR THEN SPREADS IN THURSDAY NIGHT-FRIDAY AS
THE UPPER LOW PASSES TO THE NORTH AND HEADS INTO EASTERN CANADA.
THIS ALLOWS 850 MB AIR OF -10 TO -15 C ACROSS THE AREA AND TEMPS A
GOOD 8-10F COLDER FRIDAY THAN ON THURSDAY. SOME DIFFERENCES REMAIN
WITH MODEL DETAILS AT THIS TIME...BUT CONTINUE TO FAVOR THE SIMILAR
GEM/ECMWF WHICH SUPPORTS HIGHS ONLY NEAR/AROUND 20 FRIDAY AND
SATURDAY AS ARCTIC HIGH PRESSURE BUILDS ACROSS THE MIDWEST. LOOKS
LIKE AT LEAST SOME SLIGHT MODERATION SUNDAY-MONDAY AS UPPER TROUGH
AMPLIFIES ACROSS THE WESTERN CONUS/NOAM...WITH AN AREA OF LOW
PRESSURE LIFTING ACROSS THE AREA SUNDAY WITH THE POTENTIAL FOR SOME
LIGHT SNOW.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* IFR CIGS THROUGH THE PERIOD...POSSIBLY BRIEFLY LIFTING OR
SCATTERING THIS AFTERNOON...BEFORE LOWERING/REDEVELOPING LATE
THIS EVENING.
* WIND DIRECTION...SOMEWHAT VARIABLE SE TO S AS WEAK WARM FRONT
LIFTS THROUGH THE AREA AND WASHES OUT.
* POTENTIAL FOR DENSE FOG TONIGHT.
BMD
//DISCUSSION...UPDATED 12Z...
TRICKY FORECAST ON TAP TODAY...WITH IFR CONDITIONS EXPECTED MUCH OF
THE TAF PERIOD. AN ILL-DEFINED WARM FRONTAL BOUNDARY IS DRAPED
ACROSS CENTRAL ILLINOIS AND IS EXPECTED TO GRADUALLY LIFT NORTH
ACROSS THE TERMINALS TODAY. AHEAD OF THE FRONT...IFR CIGS...FOG AND
LIGHT DRIZZLE/RAIN ARE ALL A LIKELIHOOD. WINDS WILL BE OUT OF THE
SE/SSE THROUGH MUCH OF THE DAY...AND MAY VEER BRIEFLY LATE THIS
AFTERNOON AS THE FRONTAL BOUNDARY MAKES IT NEAR THE STATE LINE
BEFORE WASHING OUT. GUIDANCE NOT IN THE BEST AGREEMENT ON WIND
DIRECTION...WITH SOME SUGGESTING WE MAY GO SSW...WHILE MOST KEEP
WIND DIRECTION SSE. ALSO...NAM GUIDANCE SUGGESTS THAT CIGS MAY
BRIEFLY SCATTER OUT SOUTH OF THE FRONT...BUT CONFIDENCE IN THIS
HAPPENING IS TOO LOW TO INCLUDE IN THE TAF AS DEEPENING AREA OF LOW
PRESSURE OVER THE PLAINS WILL BASICALLY CAUSE THE WARM FRONT TO
REORGANIZE BACK TO OUR SOUTH LATE THIS EVENING. THIS BETTER DEFINED
FRONT WILL GRADUALLY LIFT NORTH TOWARDS THE AREA TONIGHT WITH CIGS
EXPECTED TO ONCE AGAIN LOWER AND LIGHT DRIZZLE DEVELOP. THERE IS A
GOOD POSSIBILITY OF DENSE FOG DEVELOPING TONIGHT AS THE FRONTAL
TROUGH NEARS...SIMILAR TO WHAT HAPPENED ACROSS MUCH OF THE MID AND
LOWER MISSISSIPPI VALLEY THIS MORNING. MET/LAV GUIDANCE HITTING THIS
THE HARDEST...BUT FOR NOW WILL STICK WITH MAV/S MORE CONSERVATIVE
FORECAST.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM-HIGH CONFIDENCE IN IFR CIGS THROUGH THIS AFTERNOON. LOW
CONFIDENCE IN CIGS LIFTING TO MVFR OR SCATTERING OUT THIS
AFTERNOON.
* MEDIUM-HIGH CONFIDENCE IN IFR CIGS LATE THIS EVENING AND TONIGHT.
* LOW-MEDIUM CONFIDENCE IN VSBY TRENDS...AND PRECIP CHANCES/TIMING.
* MEDIUM CONFIDENCE IN WIND DIRECTION/SPEED...EXCEPT LOW-MEDIUM
CONFIDENCE IN THE AFTERNOON.
* LOW CONFIDENCE IN DENSE FOG TONIGHT.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR POSSIBLE. SLT CHC OF RAIN.
THURSDAY THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW.
MONDAY...MVFR POSSIBLE.
BMD
&&
.MARINE...
239 AM CST
STILL SIGNIFICANT DIFFERENCES IN THE MODELS WITH RESPECT TO LOW
PRESSURE THAT IS EXPECTED TO IMPACT THE LAKES MIDWEEK. GUIDANCE HAS
TRENDED TOWARDS A SLOWER FRONTAL TIMING AND MORE NORTHERLY LOW TRACK
THOUGH...A TYPICAL TREND WHEN THE UPPER AIR PATTERN IS AMPLIFIED.
WITH THAT IN MIND...HAVE BASED FORECAST TIMING ON A BLEND OF THE GEM
AND THE ECWMF WHICH HAVE BEEN FAIRLY CONSISTENT WITH SLOWER TIMING
AND WHICH THE FASTER NCEP GUIDANCE SEEMS TO BE TRENDING TOWARDS. A
DEEPENING AREA OF LOW PRESSURE IS EXPECTED TO LIFT FROM THE CENTRAL
PLAINS TODAY AND TOMORROW...ACROSS LAKE SUPERIOR OR WEDNESDAY NIGHT.
MODERATE SOUTHEAST TO EAST WINDS ARE EXPECTED AHEAD OF THE
LOW...THOUGH STABLE CONDITIONS WILL HELP KEEP THE HIGHER END GUSTS
FROM REACHING THE LAKE SURFACE. BEHIND THE FRONT...STRONG AND COLD
HIGH PRESSURE WILL OVERSPREAD THE PLAINS WITH A TIGHT GRADIENT ONLY
VERY GRADUALLY SUBSIDING THROUGH THE REST OF THE WEEK. THERE MAY BE
A SHORT PERIOD OF WESTERLY GALES IMMEDIATELY BEHIND THE FRONT
WEDNESDAY NIGHT INTO THURSDAY...WITH 30KTS REST OF THURSDAY INTO
FRIDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 3 PM TUESDAY.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
533 AM CST Tue Dec 3 2013
.DISCUSSION...
ISSUED 315 AM CST Tue Dec 3 2013
Main forecast concern continues to be potential for accumulating
snow and ice across parts of central Illinois Thursday into Friday.
SHORT TERM...Today through Thursday
Widespread fog blankets central Illinois early this morning,
thanks to light southerly winds and ample low-level moisture
flowing northward behind an advancing warm front. 08z/2am
visibilities are generally in the 2 to 4 mile range, but a few
pockets of locally dense fog are beginning to develop across
west-central and southwest Illinois. HRRR suggests visibilities may
continue to drop across this area over the next few hours. As a
result, will be issuing a Dense Fog Advisory for all locations
along and west of I-55 through 10AM. This may need to be expanded
eastward to include the remainder of the KILX CWA if visibility
trends continue. Fog will be slow to dissipate, but should clear
most of the area by around midday. Due to the fog and clouds
expected today, have trimmed previous high temperature forecast by
a few degrees, with readings ranging from the middle 50s far north
to around 60 degrees far south/southwest.
00z Dec 3 models have come into much better agreement concerning
approaching cold front on Wednesday. While the GFS/NAM remain the
fastest models, both have slowed FROPA considerably and are now
closer to the slower/more consistent ECMWF/GEM. With a clear slowing
trend noted, confidence is growing that front will remain west of
central Illinois until late Wednesday afternoon. As a result, have
boosted temperatures, with highs ranging from the lower 50s west
of the Illinois River to the middle 60s south of I-70. Rain
chances with the front still appear very low, as deepest moisture
remains further south. Will continue with just low chance POPs
during the day, with dry weather returning for all but the far SE
CWA Wednesday night into Thursday morning. Much colder air will
spill into the region behind the cold front, resulting in a 20 to
25 degree temperature drop on Thursday. Highs will range from
around 30 in the Illinois River Valley to around 40 south of I-70.
Wave of low pressure is expected to develop and track along the
departing cold front, spreading wintry precipitation into parts
of central and southeast Illinois late Thursday afternoon and
evening. Airmass will be cold enough to support snow along and
northwest of a Taylorville to Danville line, but things get a
little trickier further south. Both the NAM and GFS show a max
temp in the elevated warm layer of 3C, suggesting partial melting
of ice crystals and mixed phase precip reaching the ground. The
exact type of precip will depend on surface temps. Based on
expected afternoon highs, a mixture of snow and sleet will be
likely along the I-70 corridor, with mainly rain along and south
of highway 50 Thursday afternoon. As deeper colder air arrives,
the precip will change over to mainly snow Thursday night. The
exception will be along and south of highway 50, where warm wedge
aloft will remain strong enough to support sleet and perhaps some
freezing rain. Precip may tend to diminish/come to an end
overnight as initial wave passes to the northeast.
LONG TERM...Friday through Monday
A second wave will track along the slow-moving front on Friday:
however, its main precipitation shield is expected to be a bit
further southeast over the Ohio River Valley. Light snow or
flurries may occur as far northwest as I-55 on Friday, with the
steadier snows focused further south along/south of I-70. By the
time the precip comes to an end Friday afternoon, snowfall of
around 1 inch will be possible along a Jacksonville to Danville
line, with as much as 2 to 3 inches further south along the I-70
corridor.
Once precip shuts off, dry and very cold weather will be on tap
through Saturday with high temps only in the 20s and lows dropping
into the single digits and teens. After that, models are trying to
bring another upper-level disturbance across the region late in
the weekend, possibly bringing a period of light snow
Sunday/Sunday night. Given very dry airmass initially in place, am
skeptical that much snow will fall. Have therefore kept POPs in
the low chance category with only minimal accumulations.
&&
.AVIATION...
ISSUED 525 AM CST Tue Dec 3 2013
Coverage and duration of LIFR/VLIFR cigs and vsbys this morning the
main forecast concern.
Cigs and vsbys continue to slowly deteriorate over our area this
morning as a very mild and moist southerly flow prevails. Not
expecting any great improvement in conditions until after 16z
based on the latest short term guidance from the HRRR and HopWRF-
ARW ensembles, and that may be too optimistic as mid and upper 40
dew points stream north out of Missouri into our area today. Will
keep the LIFR to VLIFR conditions in most areas thru about 16z and
then start a gradual improving trend into the afternoon before the
possibility for more widespread LIFR to VLIFR late tonight.
Surface winds will be mostly out of a southerly direction at 8 to
13 kts today and then winds will back more into a southeast
direction tonight at 6 to 10 kts.
Smith
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY until 10 AM CST this morning FOR ILZ027>031-
036>038-040>043-047>053.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
334 AM CST TUE DEC 3 2013
.DISCUSSION...
330 AM CST
FORECAST FOCUS REMAINS LARGELY ON THE NEAR TERM THIS MORNING...
NAMELY PRECIPITATION AND TEMPERATURE TRENDS TODAY THROUGH WEDNESDAY
AS DEEP LOW PRESSURE SYSTEM DEVELOPS IN RESPONSE TO AMPLIFICATION OF
UPPER TROUGH ACROSS THE WESTERN/CENTRAL CONUS. DAYS 3-7 CONTINUE TO
FEATURE MUCH COLDER THAN AVERAGE TEMPERATURES...WITH THE POTENTIAL
FOR A COUPLE OF LIGHT SNOW EVENTS MAINLY ACROSS THE FAR SOUTHEAST
LATE THURSDAY-FRIDAY...AND FOR MOST OF THE AREA SUNDAY/SUNDAY NIGHT.
00Z RAOB ANALYSIS INDICATES FAIRLY ZONAL FLOW PATTERN ACROSS THE
CENTRAL CONUS...WITH A DEEP SHORT WAVE TROUGH DIGGING SOUTHEAST
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SEVERAL RELATIVELY MINOR
AMPLITUDE SHORT WAVES WERE NOTED DOWNSTREAM ACROSS THE MIDWEST...
EMANATING FROM STRONG JET STREAK DEVELOPS AROUND THE SOUTHERN
PERIPHERY OF THE DIGGING TROUGH. ONE SUCH WAVE WAS NOTED IN WATER
VAPOR IMAGERY OVER THE UPPER MISSISSIPPI VALLEY EARLY THIS
MORNING...WHICH WAS RESPONSIBLE FOR AN AREA OF WARM ADVECTION
PRECIPITATION THAT MOVED ACROSS THE FORECAST AREA OVERNIGHT AND WAS
NOW EAST OF THE REGION. A COUPLE OF MORE SUBTLE MID-LEVEL WAVES WERE
NOTED IN THE SATELLITE IMAGERY...ONE APPROACHING QUICKLY FROM
EASTERN IA...AND THE OTHER UPSTREAM ACROSS WESTERN NEBRASKA. THESE
FEATURES WILL RIPPLE QUICKLY EAST ACROSS THE AREA TODAY...MAINLY
WORKING TO MAINTAIN SOUTHERLY FLOW AND CONTINUED WARM ADVECTION INTO
THE MIDWEST. WHILE SOME SPOTTY LIGHT RAIN IS POSSIBLE WITH ANY OF
THESE SUBTLE FEATURES...UPSTREAM SOUNDINGS FROM OMA/TOP/SGF INDICATE
FAIRLY DRY MID-LEVELS. FORECAST SOUNDINGS MAINTAIN THIS DRY LAYER
ROUGHLY BETWEEN 850-650 MB WHICH SUGGESTS MAINLY SCATTERED LIGHT
RAIN OR SOME DRIZZLE WITH ONLY LIGHT QPF AMOUNTS TODAY-TONIGHT AS
FORCING WITH THESE WAVES ACT ON MOIST LOW LEVELS OR BRIEF POCKETS OF
ENHANCED MID-LEVEL MOISTURE.
WITH ONGOING WARM ADVECTION...SURFACE TEMPERATURES AND DEW POINTS
WILL CONTINUE TO SLOWLY RISE AS A WARM FRONT CURRENTLY LIFTING INTO
CENTRAL ILLINOIS MOVES NORTH. WHILE THE BOUNDARY REMAINS A BIT
DIFFUSE EARLY THIS MORNING...THE FRONT SHOULD SHARPEN AND BEGIN TO
MOVE FASTER LATER TODAY AND TONIGHT AS SURFACE LOW PRESSURE DEEPENS
TO OUR WEST ACROSS THE CENTRAL PLAINS IN RESPONSE TO HEIGHT FALLS
WITH DEEPENING WESTERN TROUGH. MODELS ARE IN FAIRLY GOOD AGREEMENT
THAT THE SURFACE WARM FRONT SHOULD LIFT INTO NORTHERN IL BY LATE
AFTERNOON...WITH THE SOUTHERN AND CENTRAL PARTS OF THE CWA GETTING
INTO THE WARM SECTOR. TEMPS SHOULD REACH THE LOW-MID 50S ALONG AND
SOUTH OF I-80 THIS AFTERNOON...WITH 40S TO THE NORTH. IT WILL REMAIN
VERY MILD TONIGHT AS THE WARM FRONT REACHES THE IL/WI BORDER...WITH
OVERNIGHT LOWS HOLDING IN THE 40S ACROSS THE CWA.
GUIDANCE REMAINS IN TWO SEPARATE CAMPS WITH THE HANDLING OF THE MAIN
SURFACE LOW AND COLD FRONT ON WEDNESDAY...WITH THE DOMESTIC MODELS
REMAINING FASTER AND INITIALLY DEEPER BEYOND 30 HOURS THAN THE UK/EC
AND CANADIAN COUNTERPARTS. THE 00Z RUNS OF THE GFS AND TO A GREATER
EXTENT THE WRF HAVE SLOWED HOWEVER...WHICH LENDS SUPPORT TO OUR
FAVORING THE SLOWER SOLUTION OF THE UKMET/ECMWF AND GEM. THUS
CONTINUE TO FAVOR THE SCENARIO OF THE SURFACE LOW LIFTING ACROSS
EASTERN IOWA INTO WI WEDNESDAY AFTERNOON...AND THE TRAILING COLD
FRONT MOVING ACROSS THE WFO LOT FORECAST AREA FAIRLY LATE IN THE
AFTERNOON AND EVENING HOURS. THIS SUPPORTS TEMPS IN THE 50S...AND
EVEN A COUPLE OF 60S FAR SOUTH...WEDNESDAY WITH THE CWA STILL IN THE
WARM SECTOR AHEAD OF THE FRONT. MID-LEVEL MOISTURE CONTINUES TO BE
LIMITED...AND ALTHOUGH LIGHT RAIN/SHOWER CHANCES DO INCREASE WITH
THE APPROACH OF THE LOW/COLD FRONT THE BEST COVERAGE AND RAINFALL
AMOUNTS EXPECTED NORTH OF THE AREA ACROSS WI AND THE NORTHERN LAKES.
THE COLD FRONT PUSHES ACROSS THE AREA WEDNESDAY EVENING...SHUTTING
OFF PRECIP AS MID/UPPER LEVELS DRY OUT. THANKS TO WEST-SOUTHWEST
FLOW ALOFT THE FIRST PUSH OF COLDER AIR IS RELATIVELY WEAK...AS THE
FRONT AND LOW LEVEL BAROCLINIC ZONE SLOW UP FROM THE OHIO VALLEY TO
THE EASTERN LAKES INTO THURSDAY. A COUPLE OF DISTURBANCES RIPPLE
NORTHEAST ALONG THIS BAROCLINIC ZONE LATE THURSDAY INTO FRIDAY...
WITH THE POTENTIAL FOR SOME LIGHT SNOW FROM CENTRAL IL INTO NORTHERN
INDIANA AND MAINLY CLIPPING THE FAR SOUTHEAST PART OF THE CWA. A
SECOND PUSH OF COLDER AIR THEN SPREADS IN THURSDAY NIGHT-FRIDAY AS
THE UPPER LOW PASSES TO THE NORTH AND HEADS INTO EASTERN CANADA.
THIS ALLOWS 850 MB AIR OF -10 TO -15 C ACROSS THE AREA AND TEMPS A
GOOD 8-10F COLDER FRIDAY THAN ON THURSDAY. SOME DIFFERENCES REMAIN
WITH MODEL DETAILS AT THIS TIME...BUT CONTINUE TO FAVOR THE SIMILAR
GEM/ECMWF WHICH SUPPORTS HIGHS ONLY NEAR/AROUND 20 FRIDAY AND
SATURDAY AS ARCTIC HIGH PRESSURE BUILDS ACROSS THE MIDWEST. LOOKS
LIKE AT LEAST SOME SLIGHT MODERATION SUNDAY-MONDAY AS UPPER TROUGH
AMPLIFIES ACROSS THE WESTERN CONUS/NOAM...WITH AN AREA OF LOW
PRESSURE LIFTING ACROSS THE AREA SUNDAY WITH THE POTENTIAL FOR SOME
LIGHT SNOW.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* IFR CIGS EXPECTED TO PERSIST THROUGH THE OVERNIGHT
HOURS...POSSIBLY BOUNCE UP TO MVFR TUESDAY.
* PINNING DOWN BEST CHANCES FOR PRECIPITATION.
* VSBY BETWEEN 1SM-4SM OVERNIGHT
BMD
//DISCUSSION...UPDATED 06Z...
WARM FRONT IS DRAPED ACROSS IOWA INTO CENTRAL ILLINOIS LATE THIS
EVENING WITH AN AREA OF SHOWERS PUSHING EAST AWAY FROM THE TERMINALS
WITH LOWERING CIGS AND VSBYS SETTING IN BEHIND. EXPECT LITTLE CHANCE
IN CONDITIONS OVERNIGHT...THOUGH VSBY MAY BE VARIABLE AT TIMES
BETWEEN 1SM AND 4 SM. THE FRONT WILL SLOWLY LIFT NORTH THROUGH THE DAY
TUESDAY WITH DRIER MID LEVEL AIR OVERSPREADING THE LOW LEVEL
MOISTURE/IFR CIGS. THIS DRY MID LEVEL AIR SHOULD INHIBIT PRECIP FROM
DEVELOPING THROUGH MOST OF THE DAY TOMORROW. CIGS MAY REBOUND
SLIGHTLY DURING THE DAY...INTO LOWER MVFR CATEGORY BETWEEN
010-015...ESPECIALLY LATE MORNING OR EARLY AFTERNOON WHEN THE FRONT
LIFTS ACROSS THE TERMINALS AND WINDS TURN SOUTHERLY. AS THE SURFACE
LOW BEGINS TO DEEPEN OVER THE PLAINS TUESDAY EVENING...ASCENT WILL
INCREASE ACROSS THE AREA AND DESPITE THE STILL MODEST DEPTH OF
MOISTURE...FEEL THIS WILL BE THE BEST CHANCE FOR LIGHT RAIN OR
DRIZZLE TO DEVELOP OVER THE AREA. SOME GUIDANCE SUGGESTS THAT IFR
CIGS WILL DEVELOP AGAIN TOMORROW NIGHT.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM CONFIDENCE ON WIND DIRECTION/SPEED.
* MEDIUM-HIGH CONFIDENCE IN IFR CONDITIONS THROUGH OVERNIGHT HOURS
...LOW-MEDIUM CONFIDENCE IN REBOUNDING SLIGHTLY TO LOW END MVFR
TUESDAY AFTERNOON. LOW CONFIDENCE IN CIG TRENDS TUESDAY NIGHT.
* MEDIUM CONFIDENCE IN VSBY TRENDS OVERNIGHT.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...MVFR CIGS POSSIBLE. CHC OF RAIN.
THURSDAY...VFR. POSSIBLE PERIOD OF LIGHT SNOW/FLURRIES.
FRIDAY THROUGH SUNDAY...VFR.
BEACHLER
&&
.MARINE...
239 AM CST
STILL SIGNIFICANT DIFFERENCES IN THE MODELS WITH RESPECT TO LOW
PRESSURE THAT IS EXPECTED TO IMPACT THE LAKES MIDWEEK. GUIDANCE HAS
TRENDED TOWARDS A SLOWER FRONTAL TIMING AND MORE NORTHERLY LOW TRACK
THOUGH...A TYPICAL TREND WHEN THE UPPER AIR PATTERN IS AMPLIFIED.
WITH THAT IN MIND...HAVE BASED FORECAST TIMING ON A BLEND OF THE GEM
AND THE ECWMF WHICH HAVE BEEN FAIRLY CONSISTENT WITH SLOWER TIMING
AND WHICH THE FASTER NCEP GUIDANCE SEEMS TO BE TRENDING TOWARDS. A
DEEPENING AREA OF LOW PRESSURE IS EXPECTED TO LIFT FROM THE CENTRAL
PLAINS TODAY AND TOMORROW...ACROSS LAKE SUPERIOR OR WEDNESDAY NIGHT.
MODERATE SOUTHEAST TO EAST WINDS ARE EXPECTED AHEAD OF THE
LOW...THOUGH STABLE CONDITIONS WILL HELP KEEP THE HIGHER END GUSTS
FROM REACHING THE LAKE SURFACE. BEHIND THE FRONT...STRONG AND COLD
HIGH PRESSURE WILL OVERSPREAD THE PLAINS WITH A TIGHT GRADIENT ONLY
VERY GRADUALLY SUBSIDING THROUGH THE REST OF THE WEEK. THERE MAY BE
A SHORT PERIOD OF WESTERLY GALES IMMEDIATELY BEHIND THE FRONT
WEDNESDAY NIGHT INTO THURSDAY...WITH 30KTS REST OF THURSDAY INTO
FRIDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 3 PM TUESDAY.
&&
$$
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
National Weather Service Lincoln IL
315 AM CST Tue Dec 3 2013
.DISCUSSION...
ISSUED 315 AM CST Tue Dec 3 2013
Main forecast concern continues to be potential for accumulating
snow and ice across parts of central Illinois Thursday into Friday.
SHORT TERM...Today through Thursday
Widespread fog blankets central Illinois early this morning,
thanks to light southerly winds and ample low-level moisture
flowing northward behind an advancing warm front. 08z/2am
visibilities are generally in the 2 to 4 mile range, but a few
pockets of locally dense fog are beginning to develop across
west-central and southwest Illinois. HRRR suggests visibilities may
continue to drop across this area over the next few hours. As a
result, will be issuing a Dense Fog Advisory for all locations
along and west of I-55 through 10AM. This may need to be expanded
eastward to include the remainder of the KILX CWA if visibility
trends continue. Fog will be slow to dissipate, but should clear
most of the area by around midday. Due to the fog and clouds
expected today, have trimmed previous high temperature forecast by
a few degrees, with readings ranging from the middle 50s far north
to around 60 degrees far south/southwest.
00z Dec 3 models have come into much better agreement concerning
approaching cold front on Wednesday. While the GFS/NAM remain the
fastest models, both have slowed FROPA considerably and are now
closer to the slower/more consistent ECMWF/GEM. With a clear slowing
trend noted, confidence is growing that front will remain west of
central Illinois until late Wednesday afternoon. As a result, have
boosted temperatures, with highs ranging from the lower 50s west
of the Illinois River to the middle 60s south of I-70. Rain
chances with the front still appear very low, as deepest moisture
remains further south. Will continue with just low chance POPs
during the day, with dry weather returning for all but the far SE
CWA Wednesday night into Thursday morning. Much colder air will
spill into the region behind the cold front, resulting in a 20 to
25 degree temperature drop on Thursday. Highs will range from
around 30 in the Illinois River Valley to around 40 south of I-70.
Wave of low pressure is expected to develop and track along the
departing cold front, spreading wintry precipitation into parts
of central and southeast Illinois late Thursday afternoon and
evening. Airmass will be cold enough to support snow along and
northwest of a Taylorville to Danville line, but things get a
little trickier further south. Both the NAM and GFS show a max
temp in the elevated warm layer of 3C, suggesting partial melting
of ice crystals and mixed phase precip reaching the ground. The
exact type of precip will depend on surface temps. Based on
expected afternoon highs, a mixture of snow and sleet will be
likely along the I-70 corridor, with mainly rain along and south
of highway 50 Thursday afternoon. As deeper colder air arrives,
the precip will change over to mainly snow Thursday night. The
exception will be along and south of highway 50, where warm wedge
aloft will remain strong enough to support sleet and perhaps some
freezing rain. Precip may tend to diminish/come to an end
overnight as initial wave passes to the northeast.
LONG TERM...Friday through Monday
A second wave will track along the slow-moving front on Friday:
however, its main precipitation shield is expected to be a bit
further southeast over the Ohio River Valley. Light snow or
flurries may occur as far northwest as I-55 on Friday, with the
steadier snows focused further south along/south of I-70. By the
time the precip comes to an end Friday afternoon, snowfall of
around 1 inch will be possible along a Jacksonville to Danville
line, with as much as 2 to 3 inches further south along the I-70
corridor.
Once precip shuts off, dry and very cold weather will be on tap
through Saturday with high temps only in the 20s and lows dropping
into the single digits and teens. After that, models are trying to
bring another upper-level disturbance across the region late in
the weekend, possibly bringing a period of light snow
Sunday/Sunday night. Given very dry airmass initially in place, am
skeptical that much snow will fall. Have therefore kept POPs in
the low chance category with only minimal accumulations.
Barnes
&&
.AVIATION...
ISSUED 1140 PM CST Mon Dec 2 2013
Lower clouds continue to move northeast out of the area, but are
affecting BMI for another hour or two, and may affect CMI for an
hour. Reminder of the sites have only a large mid deck of clouds
around 12kft moving over them; which will affect BMI and CMI
shortly. Light fog remains an issue as well and will it will
remain foggy at all sites overnight and into the morning hours.
Vis could get lower in the morning hours so have kept a TEMPO
group at all sites for the early morning hours around sunrise. The
mid clouds around 10kft will continue into the afternoon at all
sites and into the evening hours. However, SPI and DEC appear to
become clear around sunset, while the other sites keep clouds over
them. Winds will be southeast to start and then become more
southerly during the day.
Auten
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY until 10 AM CST this morning FOR ILZ027>031-
036>038-040>043-047>053.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
345 PM CST TUE DEC 3 2013
.SYNOPSIS...
ISSUED AT 340 PM CST TUE DEC 3 2013
WARM FRONT REACHING FROM DEVELOPING LOW OVER SE CO REACHED E-NE
ACROSS CENTRAL KS TO S CENTRAL IA TO N CENTRAL IL THIS AFTERNOON. AT
21Z...SURFACE ANALYSIS AND VISIBLE SATELLITE IMAGERY INDICATED THE
BOUNDARY BETWEEN FAIRFIELD AND WASHINGTON SE TO BETWEEN GALESBURG AND
MACOMB. FOG WAS WIDESPREAD NORTH OF THIS BOUNDARY AND HAS REMAINED
DENSE THROUGH THE DAY ALONG THE HIGHWAY 20 CORRIDOR. SOUTH OF THE
BOUNDARY...TEMPERATURES WERE IN THE 50S...WHILE 40S WERE FOUND TO
THE NORTH. THE PRIMARY PUSH OF ARCTIC AIR WAS STILL IN THE
PLAINS...WHERE THE MAIN COLD FRONT REACHED FROM NW MN S-SW TO THE
NEB PANHANDLE. BEHIND THIS BOUNDARY...TEMPERATURES WERE IN THE TEENS
AND 20S.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 340 PM CST TUE DEC 3 2013
THE REBOUND OF WIDESPREAD DENSE FOG IS THE INITIAL CHALLENGE...THEN
TRENDS WITH THE PASSAGE OF THE STRONG COLD FRONT THAT IS NOW LIKELY
TO PUSH THROUGH WED AFTERNOON.
THE WARM FRONT WILL TRY TO PUSH NORTH TONIGHT AS THE CO LEE LOW
MIGRATES NORTHEAST ALONG THE BOUNDARY IN KS. THE BROAD LOW LEVEL
CONVERGENT FLOW AND MOISTURE ADVECTION AS DEWPOINTS IN THE 40S OVER
MO AND IL ARE DRAWN NORTH AND NORTHWESTWARD WILL KEEP THE LOW LEVELS
SATURATED. THE HRRR AND SREF FOG PROG TOOLS ARE IN ALIGNMENT WITH
THE CURRENT AREA OF DENSE FOG AND HAVE THIS EXPANDING BACK SOUTH AND
SOUTHWEST OVERNIGHT. THIS IS ALONG THE AREA OF CURRENT CONVERGENCE
FROM S CENTRAL IA NE TO NW IL AND HAVE EXPANDED OUR DENSE FOG
ADVISORY TO COVER THESE AREAS OVERNIGHT. HAVE THIS GOING UNTIL NOON
WEDNESDAY...WHEN THE ENHANCED MIXING AHEAD OF THE FRONT SHOULD BRING
SOME IMPROVEMENT. ACROSS FAR SOUTHEAST IA...FAR NE MO AND WEST
CENTRAL IL ALONG THE I-80 CORRIDOR...FOG WILL LIKELY RETURN...BUT
THERE IS LOW CONFIDENCE AS TO WHETHER IT WILL BECOME DENSE. HAVE
THUS HELD OFF ON AN ADVISORY...BUT WILL NEED TO MONITOR CLOSELY.
OTHERWISE...THE DEVELOPING LIFT AND INCREASING DIFLUENCE IN FLOW
ALOFT WILL SUPPORT ANOTHER ROUND OF LIGHT RAIN...ESPECIALLY TOWARD
MORNING ACROSS THE NORTH AND HAVE MAINTAINED CHANCE POPS.
ELSEWHERE...WILL KEEP A MENTION OF DRIZZLE WITH THE FOG.
WEDNESDAY...LATEST MODELS CONTINUE TO TREND TOWARD THE
EARLIER...SLOWER ECMWF RUNS WITH THE TIMING OF THE FROPA. THE
GFS...NAM...ECMWF...AND GEM OFFER SIMILAR SOLUTIONS WITH THE WAVE OF
LOW PRESSURE MOVING OUT OF THE PLAINS...LIFTING THROUGH THE FORECAST
AREA WEDNESDAY AFTERNOON. THIS USHERS THE PRIMARY COLD FRONT THROUGH
THE AREA BY EARLY EVENING. HAVE TRENDED THE FORECAST TOWARD THE
SLIGHTLY SLOWER ECMWF AND CANADIAN SOLUTIONS...KEEPING THE
PRECIPITATION IN THE FORM OF RAIN WITH A POSSIBLY RAIN/SNOW MIX IN
THE FAR NW LATE. WITH THE PRIMARY WARM SECTOR SWEEPING THROUGH THE
MUCH OF THE WARM SECTOR...WE SHOULD TAP INTO THE AIRMASS OVER
EASTERN MO AND SOUTHERN IL RESULTING IN MORNING OR EARLY AFTERNOON
HIGHS FROM THE LOWER 40S NW TO NEAR 60 IN THE FAR SE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 340 PM CST TUE DEC 3 2013
WEDNESDAY NIGHT THROUGH FRIDAY...TAKING INTO ACCOUNT A TYPE OF
ENSEMBLE FRONTAL MOVEMENT OF THE 12Z MODEL RUNS AND EVEN SLOWING
THAT DOWN SOME AS DEEPENING CYCLONE WRAPS UP SOMEWHERE ACRS
SOUTHWEST INTO CENTRAL WI WED EVENING...IT SHOULD BE PUSHING EAST OF
THE DVN CWA BY 01Z-02Z THU. CONVERGENT FORCING OFF THIS PROCESS MAY
WRING OUT SOME LIGHT RAIN OR DRIZZLE ALONG AND EAST OF THE MS RVR THE
FIRST 1-2 HRS OF THE FCST PERIOD. BUT THE MAIN OVERNIGHT WX STORY
WILL BE THE INCREASING WESTERLY POST-FRONTAL SFC WINDS AND DEVELOPING
LLVL COLD CONVEYOR IN-WRAPPING FROM THE NORTHWEST. BRISK WEST WINDS
OF 15 TO 25+ MPH SHOULD COLD AIR ADVECT TEMPS INTO THE UPPER TEENS
IN THE NORTHWEST...TO THE MID 20S IN THE EAST BY THU MORNING. THE
12Z RUNS THEN SUGGEST THAT AS 1035-1040 MB HIGH DUMPS DOWN THE
NORTHWESTERN PLAINS AND TIGHT CYCLONIC GRADIENT LINGERS SOME OFF
NORTHERN GRT LKS DEEP LOW PRESSURE CENTER...WINDY CONDITIONS TO
CONTINUE THROUGH AT LEAST MIDDAY THU WITH AMBIENT TEMPS ONLY
RECOVERING 3-5 DEGREES FROM MORNING VALUES AT 12Z THU. SINGLE DIGIT
ABOVE ZERO WIND CHILLS IN THE NORTHWESTERN HALF OF THE CWA THU AM.
THE ARCTIC FRONT SURGES SOUTH AND PRODUCES TIGHTENING LLVL
BAROCLINICITY AS IT SLOWS UNDER SOUTHWESTERLIES ACRS THE DEEP
SOUTHERN PLAINS TO SOUTHEASTERN OH RVR VALLEY. ALONG AND NORTH OF
THIS THERMAL RIBBON TO BE AN AXIS FOR WINTER STORM/ICE CONDITIONS
INTO FRI AND THERE IS STILL SOME VARIANCE BETWEEN THE LATEST RUN
SOLUTIONS OF FRONTAL PLACEMENT AND STRENGTH OF A WAVE RIPPLING UP
ALONG THIS HIGHWAY. THE MAJORITY OF THE 12Z MODEL RUNS STILL KEEP
ANY OVERRUNNING SNOW OFF TO THE SOUTHEAST OF THE CWA THU THROUGH FRI
WITH JUST A MID AND HIGH LEVEL CLOUD DECK MOVING UP ACRS PORTIONS OF
THE CWA LATE IN THE DAY AND OVERNIGHT. BUT THE 12Z RUN NAM AND GEM
ARE MORE BULLISH AND FURTHER NORTH WITH THE OVERRUNNING PRECIP
SHIELD AND CLIP AT LEAST THE SOUTHEASTERN THIRD OF THE DVN CWA WITH
LIGHT SNOW THU NIGHT INTO FRI MORNING. FOR NOW WILL MAINTAIN SLIGHT
CHC POPS ACRS THE FAR SOUTH AND SOUTHEASTERN CORNER OF THE FCST
AREA. MOSTLY CLOUDY...BLUSTERY AND COLD CONDITIONS CONTINUE ON FRI
WITH HIGHS ONLY IN THE UPPER TEENS TO LOWER 20S. THE INCOMING SFC
RIDGE WILL LOOK TO UNFOLD ACRS THE UPPER MS RVR VALLEY FRI NIGHT FOR
CLEARING...SFC WIND DECREASING AND COLD CONDITIONS. MANY LOWS IN THE
SINGLE DIGITS WITH A ZERO EVEN POSSIBLE IN THE NORTHWEST.
SATURDAY AND SUNDAY...THE SFC RIDGE MAINTAINS LOCALLY LONG ENOUGH FOR
A FAIR WX BUT COLD DAY SAT WITH HIGHS IN THE TEENS TO AROUND 20 AS
L/W TROF LOOMS ACRS THE SOUTHWESTERN CONUS/GRT BSN. THE MEDIUM RANGE
SOLUTIONS THEN SUGGEST NORTHERN STREAM UPPER JET ENERGY/TROFFINESS
ACRS WESTERN INTO CENTRAL CANADA TO TRY AND PHASE WITH THIS SW
CONUS LONG WAVE. THE LATEST MODEL RUNS PROBABLY STILL TRYING TO GET A
HANDLE ON THIS PROCESS AND IT WILL BE SUBJECT TO CHANGE...BUT THE
CURRENT SIGNAL SUGGESTS AT LEAST A DECENT SIZED PIECE OF WAVE ENERGY
EJECTING OUT OF THE SOUTHERN PLAINS AND THEN SOMEWHERE UP THE OH
RVR VALLEY OR EVEN FURTHER TO THE NORTHWEST SUNDAY INTO MONDAY. WITH
COLD AIR IN PLACE...THIS COULD SPELL AN EXTENDED PERIOD OF SNOW
MOVING UP ACRS PORTIONS OR ALL OF THE DVN CWA STARING OUT LATE SAT
NIGHT IN THE SOUTHWEST...AND THEN CONTINUING THROUGH LATE SUNDAY
NIGHT OR EARLY MON MORNING. THE CURRENT MODELS INCLUDING THE 12Z RUN
GFS AND ECMWF SUGGEST THE BETTER MOISTURE TRANSPORT TO FUEL HEAVIER
PRECIP TO GET PINCHED OFF/REMAIN TO THE SOUTH AND SOUTHEAST OF THE
LOCAL FCST AREA...WITH JUST SECONDARY SNOWS OF 1-3 INCHES ACRS THE
DVN CWA BY 12Z MON...SNOW MOVING OUT JUST AFTER THAT TIME-FRAME. BUT
THE DURATION/24 HRS OF ROUNDS OF AT LEAST LIGHT TO OCCASIONAL
MODERATE SNOW AND HIGHER LSR/S SUGGEST AMOUNTS COULD ADD UP TO BE
MORE. IF THE MOISTURE CONVEYOR IS LESS IMPEDED AND THE SYSTEM PULLS
UP FURTHER TO THE NORTHWEST...THERE MAY BE THE POTENTIAL FOR A MORE
SIGNIFICANT WINTER STORM IN PORTIONS OF OR CLOSE TO THE LOCAL AREA.
A WINDOW TO WATCH FOR SURE...AND WILL HAVE TO SEE HOW ADDITIONAL
MODEL RUNS BEHAVE AND HANDLE THE PHASING PROCESS. WILL RAISE THE CHC
POPS FOR NOW FOR SUNDAY NIGHT.
NEXT MONDAY AND TUESDAY...THE LONGER RANGE SIGNALS SUGGEST THAT
AFTER WHAT KIND OF SYSTEM CAN MAKE IT THROUGH OR CLOSE TO THE AREA
SUNDAY INTO EARLY MONDAY...A VERY COLD AIRMASS THEN LOOMS ACRS
CANADA. THE FRESHLY PHASED L/W TROF WILL THEN BECOME COLD CORE AND
ACT AS AN ARCTIC CONDUIT ALLOWING A COLD DUMP DOWN THE NORTHERN
PLAINS AND UPPER MIDWEST LATER MONDAY INTO TUE. THE 12Z GFS HAS A
FRIGID H85 MB COLD POOL OF -20 TO -26C BARRELING IT/S WAY DOWN
ACRS MOST OF THE CWA BY 12Z TUE...THE 12Z ECMWF IS ADVERTISING -19 TO
-21C. EVEN WITH MIXING WINDS WHICH WILL BE BRISK IN THIS TYPE OF
CAA UNDER CYCLONIC FLOW...TEMPS BY TUE MORNING MAY GO SUB-ZERO. MAY
BE WIND CHILL ADVISORY CRITERIA ATTAINED IN PORTIONS OF THE AREA LATE
MON NIGHT AND THROUGH MIDDAY TUE. WELL AGAIN...MANY SYSTEMS AND
PHASING PROCESSES TO GO THROUGH TO GET TO THIS EXTENDED PERIOD BUT
WILL START TO TREND TEMPS DOWN. ..12..
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
UPDATED AT 340 PM CST TUE DEC 3 2013
WIDESPREAD FOG AND LOW CLOUDS RESULTING IN IFR AND LIFR
CONDITIONS ALONG AND NORTH OF A WARM FRONT EXTENDING ACROSS
SOUTHERN IA AND CENTRAL IL WILL REMAIN IN PLACE UNTIL A COLD FRONT
PUSHES THROUGH WEDNESDAY AFTERNOON. CONDITIONS WILL BE WORST AT
DBQ...WHERE ONLY MINOR IMPROVEMENT IS EXPECTED THIS AFTERNOON. VISIBILITIES
BELOW 1/4 MILE AND CIGS ONLY A COUPLE HUNDRED FEET WILL RESULT IN
VLIFR...WITH ONLY TEMPORARY IMPROVEMENTS TO LIFR EXPECTED THIS
AFTERNOON. ELSEWHERE...BRL MAY SEE SOME PERIODS OF MVFR INTO EARLY EVENING...
WHILE DBQ AND MLI REMAIN IFR OR LOWER. EVEN THESE SITES SHOULD
AGAIN SEE LOWERING CONDITIONS TONIGHT WITH WIDESPREAD LIFR AND
VLIFR DUE TO THE DENSE FOG...LOW CLOUDS AND PATCHY LIGHT RAIN OR
DRIZZLE THROUGH WEDNESDAY MORNING.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR BENTON-BUCHANAN-
CLINTON-DELAWARE-DUBUQUE-JACKSON-JONES-LINN.
DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR CEDAR-HENRY IA-
IOWA-JEFFERSON-JOHNSON-KEOKUK-LOUISA-MUSCATINE-SCOTT-VAN
BUREN-WASHINGTON.
IL...DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR CARROLL-JO
DAVIESS-STEPHENSON-WHITESIDE.
DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR ROCK ISLAND.
MO...NONE.
&&
$$
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...12
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1149 PM CST MON DEC 2 2013
.SHORT TERM /TONIGHT/...
ISSUED AT 424 PM CST MON DEC 2 2013
SKIES ARE CLEARING RAPIDLY FROM WEST TO EAST THIS AFTERNOON...BUT
SOME HIGH CLOUDS ARE FILLING BACK IN FROM THE NORTHWEST PER
SATELLITE IMAGERY. AS EXPECTED A WARM FRONT HAS NOSED INTO OUR SOUTH
AND SOUTHWEST AND CONTINUES TO ADVANCE TOWARD CENTRAL
IOWA...BRINGING TEMPERATURES IN THE 50S WITH IT. A QUIET NIGHT IS IN
STORE AS WINDS REMAIN GENERALLY FROM THE SOUTHEAST BUT MID/HIGH
CLOUDS STEADILY THICKEN AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM.
THIS WILL RESULT IN TEMPERATURES STAYING RELATIVELY WARM IN THE MID
TO UPPER 30S IN MOST AREAS OVERNIGHT. FORECAST SOUNDINGS ALSO
INDICATE THAT BY SUNRISE TUESDAY THERE WILL BE QUITE A DEEP
SATURATED LAYER ASSOCIATED WITH THE MID/HIGH CLOUDS...HOWEVER A
POWERFUL NEAR SURFACE DRY LAYER WILL REMAIN IN PLACE. THIS SHOULD
RESULT IN A SCENARIO SIMILAR TO THIS MORNING WHEREBY ANY PRECIP THAT
FORMS LATE TONIGHT WILL FALL IN THE FORM OF VIRGA EVAPORATING BEFORE
IT HITS THE SURFACE...THEN DURING THE DAY TUESDAY PRECIP WILL BE
MORE LIKELY TO REACH THE GROUND AT TIMES. THUS HAVE REMOVED POPS
OVERNIGHT...ALTHOUGH SPRINKLE WORDING MAY NEED TO BE INTRODUCED
LATER FOR THE PRE DAWN HOURS.
.LONG TERM /TUESDAY THROUGH MONDAY/...
ISSUED AT 424 PM CST MON DEC 2 2013
MAJOR CHALLENGE IN NEAR TERM IS TRACK OF LOW AND LOCATION/TIMING OF
ASSOCIATED FROPA. THE RAP HAS BEEN INITIALIZING THE BEST ALL
MORNING. BY TUESDAY AFTERNOON...GFS A LITTLE FASTER THAN RAP...AND
NAM A LITTLE SLOWER AND FURTHER SOUTH. ECMWF SEEMS TO SOMEWHAT OF AN
OUTLIER ON TRACK OF LOW. IT SEEMS THE NAM HAS THE BEST HANDLE ON THE
SITUATION...SO PUSHING BACK TIME OF COLD FROPA AND HAVE SUBSEQUENTLY
INCREASED TEMPS OVER GUIDANCE AND PREVIOUS FORECAST.
ADDITIONALLY...THERE COULD BE SOME SUNSHINE IN SOUTHWESTERN IOWA
AS DRIER AIR BEING ADVECTED INTO LOWER LEVELS...WHICH COULD
ACTUALLY HELP TEMPS WARM UP INTO THE MID 60S. DECENT MOISTURE
CONVERGENCE AND FORCING ALONG COLD FRONT. HOWEVER...SOUNDING
PROFILES NOT VERY SATURATED IN DMX CWA SO PRECIP MAY STRUGGLE TO
REACH GROUND...THUS LOW QPF FORECAST. STRONG CAA AND TEMP GRADIENT
BEHIND FRONT...SO PRECIP TYPE WILL BE TOUGH TO PIN DOWN. THE
TRANSITION ZONE FROM RAIN TO SNOW WILL BE VERY NARROW. BETTER
FORCING TOWARDS MINNESOTA...SO HIGHER POPS TO THE NORTH.
FOR THURSDAY...GFS SOUNDINGS NOW KEEP THE PROFILE VERY SATURATED
DURING THE MORNING. A FEW FLURRIES MAY FALL DURING THE MORNING...BUT
NOT A LOT OF SUPPORT IN THE ATMOSPHERE FOR ANYTHING THAT WOULD
NOTABLY IMPACT THE PUBLIC. ALL MODELS HAVE SUBSIDENCE AND DRY
NORTHWESTERLY FLOW BEING ADVECTED DOWN TO CWA...ESPECIALLY THE
NAM...DURING THE AFTERNOON. THEREFORE...THINK CLOUDS SHOULD BEGIN
TO BREAK UP DURING THE DAY. DUE TO LACK OF FORCING HAVE REDUCED
POPS FOR THURSDAY PM.
THURSDAY/S TEMPERATURES SLIGHTLY TRICKY. AS MENTIONED ABOVE...CLOUDS
COVER LIKELY TO BE PRESENT DURING THE MORNING BUT WILL BREAK UP
DURING THE AFTERNOON. ADDITIONALLY...IT APPEARS WIND SPEEDS WILL
REMAIN NEAR THE 10 TO 15KT RANGE. CAA THROUGHOUT THE DAY AS H850
TEMPS WILL START THE DAY AROUND -10C AND END THE DAY NEAR -13C.
THEREFORE WENT SEVERAL DEGREES ABOVE GUIDANCE FOR THURSDAY
MORNING...AND WILL INCREASE DAYTIME TEMPERATURES A FEW DEGREES WITH
THE ANTICIPATED SUNSHINE. IN LOCATIONS WHERE SUN CANNOT MAKE IT
THROUGH...TEMPS WILL LIKELY HOLD STEADY OR DECREASE DURING THE DAY.
BY FRIDAY MORNING...PRESSURE GRADIENT STILL PRETTY TIGHT IN ADVANCE
OF APPROACHING HIGH SO WINDS WILL STAY AT LEAST AROUND 10 KTS.
THOUGH NOT A PURE RADIATIONAL COOLING NIGHT...WITH H850 TEMPS
APPROACHING -17C...APPARENT TEMPERATURE AT SURFACE WILL APPROACH
ZERO DEGREES...AND MAY EVEN BE BELOW ZERO IN SOME LOCATIONS. SUNNY
SKIES WILL PREVAIL FOR THE AFTERNOON...BUT HIGHS WILL STRUGGLE TO
MAKE IT OUT OF THE TEENS AS NO WAA EXPECTED.
FOR THE WEEKEND...GFS AND EURO CAME INTO SLIGHTLY BETTER AGREEMENT
WITH THEIR 12Z RUNS. HOWEVER...THERE IS STILL QUITE A BIT OF
DISAGREEMENT. BOTH MODELS DEVELOP A SIZABLE TROUGH THAT PUSHES OFF
THE ROCKIES. THE EURO HAS A MUCH MORE SOUTHERLY TRACK...PUTTING THE
REGION INTO SOUTHWESTERLY FLOW AND BRINGING MUCH GREATER CHANCE FOR
WINTRY PRECIP TO THE AREA. THE GFS ENSEMBLES KEEP THE LOW FURTHER
NORTH...KEEPING THE CWA IN WESTERLY TO NORTHWESTERLY FLOW...WHICH
WOULD KEEP COOL...DRY AIR ALOFT AND REDUCE PRECIPITATION CHANCES
FOR DMX.
&&
.AVIATION...03/06Z
ISSUED AT 1148 PM CST MON DEC 2 2013
PRIMARY CONCERN REMAINS VSBY/CIG TRENDS INTO TUE. 06Z SURFACE
ANALYSIS STILL SHOWS WARM FRONT BISECTING IA NW-SE WITH
DETERIORATING MVFR-LIFR CONDITIONS NOTED N AND E OF THE FRONT.
WITH LITTLE CHANGE ANTICIPATED OVERNIGHT...LINGERING LOW LEVEL
MOISTURE AND LIGHT SELY WINDS...EXPECT CONDITIONS TO DEGRADE
FURTHER DIURNALLY WITH AT LEAST MVFR VSBYS S AND W OF THE FRONT
AND LIFR CONDITIONS N AND E /KMCW/KALO/. CONDITIONS MAY IMPROVE
SOMEWHAT WITH INSOLATION TUE...BUT MVFR VSBYS/CIGS WILL LIKELY
LINGER AT LEAST INTO MIDDAY ALONG AND NORTH OF THE BOUNDARY WITH
LITTLE PATTERN CHANGE. LIGHT RAIN MAY ALSO CLIP FAR NRN IA /KMCW/
EARLY TUE EVENING AS WELL.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...LEE
LONG TERM...KOTENBERG
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
434 PM MST WED DEC 4 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 223 PM MST WED DEC 4 2013
ARCTIC COLD HAS ENTERED THE CWA AND IS EXPECTED TO STICK AROUND FOR
A WHILE. SOME LIGHT SNOW FELL THIS MORNING...WITH HEAVIEST BANDS
OVER EASTERN COLORADO BRINGING NEARLY AN INCH IN A FEW SPOTS.
TONIGHT ANOTHER ROUND OF SNOWFALL IS EXPECTED WHICH COULD BRING A
QUICK INCH IN A FEW SPOTS...BUT OTHERWISE THE COLD WILL BE THE MAIN
HAZARD IN THE SHORT TERM.
TODAY...SUBSIDENCE ACROSS THE TRI-STATE LEAD TO SNOWFALL ENDING AND
EVEN SOME CLEARING SKIES...AND HIGHS WERE A CHALLENGE OF BALANCING
THE ADDITIONAL SOLAR RADIATION WITH COLD AIR ADVECTION. WINDS ARE A
BIT STRONGER THAN THE ORIGINAL FORECAST...BUT A BLEND OF 12Z MOS
GUIDANCE HANDLED THE STRONGER WINDS A LITTLE BETTER THAN MOST OF THE
OTHER GUIDANCE.
TONIGHT...MUCH OF EASTERN COLORADO AND PARTS OF NW KANSAS/SW
NEBRASKA WILL REACH LOWS NEAR OR BELOW ZERO...APPROACHING RECORD
COLD VALUES. A QUICK CHANCE FOR SNOWFALL DUE TO A NARROW BAND
ENHANCED FRONTOGENESIS AS SUGGESTED BY SHORT RANGE GUIDANCE. A FEW
SPOTS NEAR AND SOUTH OF I-70 COULD SEE UP TO AN INCH...BUT ANY
SNOWFALL THAT DOES FALL WILL BE QUICK TO EXIT. SNOWFALL AND CLOUD
COVER WILL LIMIT TEMPS IN THE EVENING HOURS...BUT ONCE THE SNOW
SHOWERS AND CLOUDS MOVE OUT TEMPERATURES WILL DROP RAPIDLY AS COLD
AIR PUSHES SOUTHWARD...850 TEMPS DROPPING TO NEAR -20 C...VERY COLD
EVEN BY WINTER STANDARDS. LOWS WILL BE NEAR TO BELOW
ZERO...APPROACHING RECORD VALUES FOR MANY LOCATIONS. COMBINED WITH
WINDS OF 20-25 MPH AM VERY CONFIDENT ADVISORY-LEVEL WIND CHILL
VALUES AS WIND CHILLS DROP TO -15 TO -25...ESPECIALLY IN EASTERN
COLORADO. IF SKIES CLEAR AS RAPID AS THE RUC IS INDICATING...EVEN
COLDER TEMPS/WIND CHILLS ARE POSSIBLE.
THURSDAY...COLD. HIGHS WILL STRUGGLE TO REACH THE TEENS...EVEN WITH
PARTIAL SUNSHINE. WINDS WILL BE LIGHT...WITH WIND CHILLS WILL BE
NEAR ZERO MUCH OF THE DAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 223 PM MST WED DEC 4 2013
THURSDAY NIGHT-FRIDAY NIGHT...H5 LONGWAVE TROUGH WILL REMAIN IN
PLACE WITH ARCTIC AIR MASS AT THE SURFACE. LOOKS LIKE THERE WILL BE
VERY LITTLE CHANGE IN TEMPS WITH HIGHS IN THE TEENS AND LOWS AROUND
ZERO. MY CURRENT LOW TEMP FORECAST IS A CONSERVATIVE BLEND...AND IF
SKIES CLEAR NEAR DAYBREAK FRIDAY MORNING WE COULD SEE RECORD LOWS IN
THE -5 TO -15F BELOW ZERO RANGE. EVEN WITH SLIGHTLY WARMER TEMPS WE
WILL PROBABLY NEED TO CONSIDER WIND CHILL ADVISORIES BOTH NIGHTS.
MODELS SHOW SOME WEAK ENERGY ROTATING THROUGH THE BASE ON THE LARGE
SCALE TROUGH. BEYOND INCREASING CLOUD COVER THE FORECAST SHOULD
REMAIN DRY DURING THESE PERIODS. I DECIDED AGAINST MENTION OF
FLURRIES...THOUGH I COULDNT RULE OUT A FEW FLURRIES DURING THE
DAYTIME PERIOD THURSDAY IF WE ARE ABLE TO GET SOME WEAK INSTABILITY.
SATURDAY-SUNDAY NIGHT...THE NEXT GOOD CHANCE FOR ACCUMULATING SNOW
LOOKS TO ARRIVE THIS WEEKEND WHEN A SHORTWAVE TROUGH ORIGINATING
OVER THE PACIFIC NW MOVES TO THE FOUR CORNERS REGION SATURDAY AND
ACROSS THE PLAINS AS A NEGATIVELY TILTED TROUGH SUNDAY. VERY GOOD
FORCING AHEAD OF THIS FEATURE AND DECENT MOISTURE ADVECTION SHOULD
COMBINE TO PRODUCE ACCUMULATING SNOW FOR A LARGE PORTION OF THE
PLAINS. MODELS GENERALLY SHOW SIMILAR TIMING ON THIS
FEATURE...HOWEVER THERE IS LESS CONTINUITY ON THE TRACK AND THIS
WILL HAVE A LARGE IMPACT ON SNOW TOTALS OVER OUR CWA. DURING THIS
FORECAST UPDATE I BUMPED POPS UP SOME ON SATURDAY NIGHT AND SUNDAY
TO HIGH CHANCE CATEGORY WITH INCREASING CONFIDENCE IN MEASURABLE
SNOW. BEST GUESS BASED ON A MEAN STORM TRACK PUTS SNOW AMOUNTS IN
THE 1-3" RANGE OVER OUR CWA WITH THE HIGHEST AMOUNTS ACROSS THE
SOUTHEAST WHERE BETTER FORCING ASSOCIATED WITH MID LEVEL
FRONTOGENETICAL BAND HAS A BETTER CHANCE OF SETTING UP.
MONDAY-WEDNESDAY...DRY FORECAST IS EXPECTED WITH UPPER LEVEL
CONFLUENCE AND H5 PATTERN BECOMING SLIGHTLY MORE ZONAL. MODELS DO
ADVERTISE A GRADUAL WARMING TREND WITH HIGHS FINALLY APPROACHING (OR
GOING ABOVE) FREEZING BY TUESDAY AND WEDNESDAY. NORTHERN JET STREAM
STILL APPEARS TO BE VERY ACTIVE HOWEVER SO ADDITIONAL REINFORCING
SHOTS OF COLD AIR COULD KEEP OUR TEMPERATURES BELOW NORMAL THROUGH
NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 424 PM MST WED DEC 4 2013
VFR CONDITIONS CAN BE EXPECTED FOR MOST OF THE TAF PERIOD FOR
BOTH SITES. HOWEVER...KGLD COULD SEE TEMPORARY MVFR CONDITIONS
WITH THE LIGHT SNOW CURRENTLY IN EASTERN COLORADO THAT WILL MOVE
INTO THE TERMINAL BETWEEN NOW AND 03Z. THE MAIN FORCING INDUCING
THE LIGHT SNOW SHOULD REMAIN TO THE SOUTH AND SOUTHEAST OF
KMCK...SO NO LIGHT SNOW IS INCLUDED AT THIS TIME. NORTHWEST WINDS
WILL CONTINUE TO GUST AROUND 25 TO 30 KTS THROUGH THE FIRST PART
OF THE TAF PERIOD...WITH GUSTS DIMINISHING AROUND OR AFTER
MIDNIGHT. HIGH CLOUDS AND LIGHTER NORTHWEST WINDS AROUND 10 KTS
WILL OCCUR EARLY IN THE MORNING AND TOMORROW AFTERNOON.
&&
.CLIMATE...
ISSUED AT 223 PM MST WED DEC 4 2013
LOW TEMPERATURES WILL APPROACH RECORD VALUES TONIGHT.
CURRENT DAILY RECORD LOWS FOR THURSDAY (DEC 5)...
GOODLAND.....-8 (1972)
HILL CITY....-5 (1909)
BURLINGTON...-11 (1972)
MCCOOK.......-10 (1909)
YUMA.........-5
TRIBUNE......-2
COLBY........-8
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND CHILL ADVISORY UNTIL 11 AM MST /NOON CST/ THURSDAY FOR
KSZ001>003-013-014-027.
CO...WIND CHILL ADVISORY UNTIL 11 AM MST THURSDAY FOR COZ090>092.
NE...WIND CHILL ADVISORY UNTIL 11 AM MST /NOON CST/ THURSDAY FOR
NEZ079>081.
&&
$$
SHORT TERM...JJM
LONG TERM...DR
AVIATION...ALW
CLIMATE...JJM
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
529 PM CST Wed Dec 4 2013
...Updated aviation section...
.SYNOPSIS...
ISSUED AT 1102 AM CST WED DEC 4 2013
At 12z Wednesday a 300mb jet extended from southern California
into far western Nebraska. A -35c to -37c 500mb low was located
over southeastern Idaho with an upper level trough extending
southwest of this upper low into southern California. Ahead of
this upper level trough 80 to 90meter 12hour height rises were
observed near the four corners region which was where the left
exit region of a 300mb +100kt jet was positioned. A 700mb
baroclinic zone stretched from the four corners region across
western Kansas and into southeastern Nebraska with an area of
higher dewpoints observed along this baroclinic zone. The 850mb
temperatures at 12z Wednesday across the central plains varied
from -3c at Amarillo to -9c at Dodge city to -16c at North Platte.
This a 18c to 25c drop when comparing the 850mb temperatures from 12z
Wednesday to 12z Tuesday. Dodge City and North Platte soundings
from 12z also indicated a fairly deep layer of moisture which
extended from near the surface to at least the 800mb level.
&&
.SHORT TERM...(This evening through Thursday)
ISSUED AT 147 PM CST WED DEC 4 2013
19z visible satellite loop indicating some clearing skies across
western Kansas as the low clouds gradually erode. Further west mid
level cloud cover/moisture was on the increase and this appears to
be related to a 700mb baroclinic zone that extended from northeast
Colorado into Nebraska. Tonight 700mb frontogenesis will be
improving along this mid level baroclinic zone as the right
entrance region of a 300mb jet crosses western Kansas. Based on
the NAM and RAP at 18z Wednesday this 700mb baroclinic zone should
be located across northeast Colorado 18z and based on the latest
composite mosaic radar loop these models appear to have a decent
handle on this. As a result will follow the 700mb baroclinic zone
from NAM and RAP overnight and place the better chances for
measurable snow along this boundary given the improving
frontogenesis and the location of the right entrance region of an
upper level jet as it crosses the central plains during the
overnight hours.
Initial thoughts for snow amounts tonight...a brief period of
steady light to even moderate snow may accompany the jet steak
which may result in a quick inch of snow across portions of west
central and north central Kansas. Have therefore place snow
accumulations of 1 to around 1.5 inches in this this area between
00z Thursday and 12z Thursday. Further south some light
snow/flurries will still be possible, however given the loss of
the upper level dynamics lower snow amounts are anticipated.
On Thursday the better mid level forcing will be located near the
Oklahoma border through much of the day as a southern branch upper
level disturbance approaches southwest Kansas from New Mexico.
Another brief period of steady light to moderate snow will be be
possible during the day across far southwest Kansas and near the
Oklahoma border. Once again 1 to 2 inches of snowfall will be
possible with this steadier snow and lower snow amounts further
north. At this time snow totals over the next 24 to 36 hours are
expected to be mainly between 1 to 2 inches so inserted these snow
totals into the hazardous weather outlook but will not issue a
winter weather advisory at this time.
Wind chill values towards daybreak will fall back mainly into the
5 to 10 degrees below zero range with wind chill readings
approaching -15c in a few locations of west central Kansas. On
Thursday as afternoon temperatures struggle to reach the 15 to
near 20 degree range the wind chill values are expected to be
mainly in the single digits.
.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 222 PM CST WED DEC 4 2013
Thursday night/Friday:
Precipitation will be quickly diminishing after 00Z Friday as the 700
mb frontogenesis and 285 Kelvin isentropic lift slides off to the
southeast. Minimums will continue to be cold and in the single
digits. will have to watch out for the possible need for a wind
chill advisory as apparent temperatures approach -15F,
particularly during the morning on Friday. Otherwise, a
precipitation free forecast is expected Friday as isentropic
downglide develops in the wake of the passing synoptic trof.
Maximums Friday will be in the teens and have gone with the colder
bias correct guidance as 850 mb temperatures remain 2 to 3 standard
deviations below normal.
Saturday and beyond:
250 mb flow will eventually transition from westerly Saturday to
southwesterly Sunday as the next 400 mb pv anomaly moves across the
central Rockies and eventually ejects out across the prairies.
This signature is quite impressive per ECMWF fields and displays
the classic treble clef signature. At the low levels, 850-600 mb
frontogenesis and 280-290 Kelvin isentropic lift develops across
west central Kansas Sunday. Have ramped up precipitation
probabilities in this region during the day. The GEM and ECMWF
indicate the potential for a low end snow advisory for Sunday.
This is something to continue to watch as we get closer to the
event. Otherwise, the rest of the forecast will feature fairly
tranquil weather and cold temperatures.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 526 PM CST WED DEC 4 2013
VFR conditions will prevail tonight with northerly winds at 15 to
20 knots gusting to around 25 knots at times. There is a slight
chance of light snow towards sunrise and have placed a TEMPO group
to account for this. Northerly winds then decrease to around 10
knots tomorrow morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 9 16 6 16 / 30 60 60 0
GCK 9 16 4 14 / 50 40 40 0
EHA 7 14 5 15 / 50 50 50 0
LBL 11 17 7 16 / 40 80 80 0
HYS 8 18 1 15 / 60 20 20 0
P28 14 22 11 19 / 20 50 50 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Sugden
AVIATION...Hovorka_42
AREA FORECAST DISCUSSION
NWS GOODLAND KS
238 PM MST TUE DEC 3 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 157 PM MST TUE DEC 3 2013
AS OF 3 PM CST...2 PM MST...SKIES ACROSS THE TRI-STATE AREA RANGED
FROM PARTLY CLOUDY TO OVERCAST AS HIGH CIRRUS CONTINUES TO PASS
OVER. TEMPERATURES REACHED THE LOW TO MID 60S ACROSS THE AREA WITH
THE EXCEPTION OF SOUTHWEST NEBRASKA. A BACK DOOR COLD FRONT HAS
MOVED IN FROM THE NORTHEAST...KEEPING THINGS ACROSS THE NORTHEASTERN
THIRD OF THE FORECAST AREA COOLER. WINDS HAVE BEEN FROM THE SOUTH
AHEAD OF THE COLD FRONT AND NORTHEAST BEHIND THE BACKDOOR FRONT. THE
MAIN COLD FRONT WAS FINALLY BEGINNING TO MAKE ITS SURGE INTO
NORTHEAST COLORADO. THE FRONT WAS BLOCKED BY A STRONG LEE TROUGH
CENTERED BETWEEN DENVER AND LIMON. THIS LEE TROUGH IS NOW STARTING
TO MOVE SOUTHEAST FROM LATEST RAP MSL ANALYSIS...ALLOWING THE MAIN
COLD FRONT TO SURGE SOUTH.
FOR THIS AFTERNOON AND TONIGHT...THE STRONG ARCTIC FRONT WILL MAKE
ITS PRESENCE FELT AS IT MOVES SOUTH. TEMPERATURES DROP RAPIDLY BY
THE FRONT AS SEEN BY THE 15 TO 20 DEGREE DROPS IN ONE HOUR AT YUMA
AND AKRON COLORADO. IMMEDIATELY BEHIND THE FRONT...GUSTY NORTH WINDS
ARE EXPECTED. WINDS NEAR WIND ADVISORY CRITERIA HAVE NOT BEEN
OBSERVED AND MODELS HAVE BACKED OFF ON WIND SPEEDS FROM YESTERDAYS
RUNS. THERE COULD BE SOME GUSTS THAT APPROACH WIND ADVISORY CRITERIA
BUT THIS SHOULD NOT BE WIDESPREAD NOR PERSISTENT. LOW TEMPERATURES
TONIGHT SHOULD BE ABLE TO DROP INTO THE LOW 10S TO LOW 20S EVEN WITH
DENSE CLOUD COVER. FOR PRECIPITATION CHANCES...MOST OF THE
PRECIPITATION WILL LIKELY HOLD OFF UNTIL AFTER 00Z WITH CHANCES
GRADUALLY INCREASING THROUGHOUT THE NIGHT. MODELS INDICATE THAT THE
ATMOSPHERE GRADUALLY SATURATES THROUGH THE NIGHT...ALLOWING SNOW TO
BEGIN FALLING THIS EVENING OR EARLY TOMORROW MORNING. SOUTHEAST
PORTIONS OF THE FORECAST AREA SHOULD MISS OUT ON THE PRECIPITATION
FOR THE MOST PART BUT COULD SEEM SOME FLURRIES. ACCUMULATIONS WILL
BE LIGHT AS ALL MODELS SHOW LIGHT QPF WITH HEAVIER AMOUNTS WEST
WHERE TERRAIN EFFECTS AND LIFT ARE STRONGER.
FOR TOMORROW...COLD WEATHER WILL CONTINUE WITH HIGH TEMPERATURES LESS
THAN 10 DEGREES WARMER THAN LOW TEMPERATURES TONIGHT. HIGHS ARE ONLY
ADVERTISED TO BE IN THE LOW 10S OVER NORTHEAST COLORADO TO THE MID
20S OUT NEAR HILL CITY. THIS COULD BE GENEROUS CONSIDERING THAT
DENSE CLOUD COVER AND NORTH WINDS SHOULD PERSIST. CHANCES FOR LIGHT
SNOW CONTINUE IN THE MORNING HOURS BEFORE CHANCES DECREASE ACROSS
NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. CHANCES SHOULD CONTINUE
OVER EAST COLORADO WITH A SLIGHT UPSLOPE COMPONENT AND A BETTER
ATMOSPHERIC MOISTURE PROFILE. AGAIN...ONLY LIGHT ACCUMULATIONS ARE
EXPECTED WITH LITTLE IMPACT TO TRAVEL. ANOTHER THING TO NOTE ABOUT
TOMORROW IS THAT WITH THE NORTH WINDS AND COLD TEMPERATURES...WIND
CHILLS SHOULD REMAIN IN THE SINGLE DIGITS ABOVE ZERO THROUGHOUT THE
DAY WITH BELOW ZERO WIND CHILLS POSSIBLE IN EAST COLORADO. NEEDLESS
TO SAY...TOMORROW WILL BE MUCH COLDER WITH HIGH TEMPERATURES ON THE
ORDER OF 20 TO 45 DEGREES COOLER DEPENDING ON THE LOCATION.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 157 PM MST TUE DEC 3 2013
COLD AIR WILL BE THOROUGHLY ENTRENCHED ACROSS THE CENTRAL HIGH
PLAINS REGION AND IS EXPECTED TO REMAIN IN PLACE THROUGH THE
FORECAST PERIOD. FLURRIES TO LIGHT SNOW WILL CONTINUE ACROSS
PORTIONS OF THE FORECAST AREA THROUGH THURSDAY NIGHT AS THE MAIN
UPPER TROUGH AND A COUPLE OF PRECEDING SHORT WAVE TROUGHS LIFT
OUT OF THE SOUTHWEST UNITED STATES AND ACROSS THE HIGH PLAINS REGION.
FRIDAY AND FRIDAY NIGHT WILL BE DRY AND COLD WITH HIGH PRESSURE IN
PLACE AT THE SURFACE IN THE WAKE OF THE UPPER TROUGH AS IT MOVES
QUICKLY TO THE EAST. LATE SATURDAY THROUGH SUNDAY BRINGS ANOTHER
CHANCE OF LIGHT SNOW AS THE NEXT UPPER LOW CENTER MOVES OUT OF THE
SOUTHWEST UNITED STATES AND INTO THE CENTRAL UNITED STATES.
MONDAY THROUGH TUESDAY WILL BE DRY AGAIN IN THE WAKE OF THE SECOND
UPPER SYSTEM WHILE COLD HIGH PRESSURE REMAINS IN PLACE...KEEPING
TEMPERATURES ABOUT 20 DEGREES COLDER THAN AVERAGE THROUGH THE
LONG TERM PORTION OF THE FORECAST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1045 AM MST TUE DEC 3 2013
COMPLICATED WEATHER SCENARIO WILL UNFOLD DURING THE TAF PERIOD. A
STRONG COLD FRONT WILL MOVE THROUGH BOTH TAF SITES...BRINGING
GUSTY NORTH WINDS AND REDUCED CIGS/VIS. AN EASTERN SURGE OF THE
FRONT IS ALREADY THROUGH KMCK WITH THE STRONGER SURGE NOW
ENTERING NORTHEAST COLORADO. AHEAD OF THE FRONT AT KGLD...SOUTH
WINDS HAVE PICKED UP BUT SHOULD RELAX IMMEDIATELY AHEAD OF THE
FRONT. BEHIND THE INITIAL SURGE...CIGS HAVE DROPPED TO LIFR WITH
SOME IFR VIS ACROSS SOUTHWEST NEBRASKA AND THINKING THIS WILL
MAKE IT TO KMCK OVER THE NEXT 2-3 HOURS. LOW CIGS/VIS WILL TAKE
LONGER TO MAKE IT TO KGLD...LIKELY HOLDING OFF UNTIL MAIN SURGE OF
THE FRONT PASSES THROUGH AROUND 00Z OR AFTER. LOW CIGS/VIS AND
GUSTY NORTH WINDS ARE EXPECTED TO CONTINUE BEHIND THE FRONT MOST
OF THE NIGHT AT BOTH SITES. TOMORROW...HAVE INCLUDED MENTIONS OF
SNOW AS AN UPPER LEVEL DISTURBANCE MOVES THROUGH. SNOW SHOULD NOT
BE HEAVY BY ANY STRETCH...LIKELY RANGING FROM A FEW FLURRIES TO
LIGHT SNOW SHOWERS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...RRH
LONG TERM...LOCKHART
AVIATION...RRH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
225 PM CST Tue Dec 3 2013
...Updated Short term discussion...
.SYNOPSIS...
ISSUED AT 1106 AM CST TUE DEC 3 2013
At 12z Tuesday a -35c 500mb low was located over Idaho/western
Montana. A +100kt 300mb jet streak was located in the based of
this upper low and extended from northern Nevada into southern
Wyoming. 700 mb level difluent flow appears to be located across
eastern Wyoming. This was located near the left exit region of
the 300mb jet. Across the Central Plains earlier this morning the
850mb temperatures ranged from +10C at North Platte to +15c at
Amarillo. Dodge City this morning had a 850mb temperature of +13c.
A surface cold front was located across Nebraska at 12z Tuesday.
North of this surface cold front low clouds, gusty north winds and
light snow/fog were observed from the surface observations across
eastern Wyoming and northwest Nebraska. Surface temperatures under
the status were mainly in the 20s. 850mb temperatures north of
this front varied from -9c at South Dakota to -13c at Glasgow MT.
&&
.SHORT TERM...(This evening through Wednesday)
ISSUED AT 222 PM CST TUE DEC 3 2013
12z NAM and GFS along with the latest HRRR and RAP were all in
decent agreement with a cold front surging south across western
Kansas during the overnight hours. Based on 18z verification
between the models and the surface observations the 2m
temperatures across Nebraska from NAM and HRRR were within 3
degrees of the actual temperature, and both of these models were
close with the surface front location. 12z NAM model soundings
across Nebraska also appeared to be picking up on the status
behind this front as well. As a result will stay close to the NAM
and HRRR on timing of the wind shift overnight along with the
magnitude of the cold air advection that will be developing behind
this front overnight as low clouds thicken across western Kansas.
Given the current temperatures behind this front in northern
Nebraska, status and cold air advection that is forecast to spread
into western Kansas later tonight have decided to stay close the
previous forecast which was also similar to the latest MET
guidance. Gusty north winds at 20 to 30 mph are also expected to
develop for several hours behind this front later tonight based
given the tight surface pressure gradient and 925-850mb winds of
25 to 35 knots. These gusty winds by daybreak will easily result
in wind chill values in the single digits by early Wednesday
morning. Isentropic lift/warm air advection along with a deepening
moist layer across portions of north central Kansas approaches a
depth favorable for some very light precipitation, however at
this time have decided not to introduce any type of very light
precipitation east of 183.
On Wednesday the status will slowly erode during the afternoon
and cold air advection continues in the 900mb to 850mb layer. Based
on the 18z Wednesday and 00z Thursday 850mb temperatures from the
NAM and GFS will undercut the MET/MAV guidance for highs.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 132 PM CST TUE DEC 3 2013
Wednesday night/Thursday:
The 03.012Z ECMWF, NAM, and GEM were indicating the potential for some
snow Wednesday night but mainly into Thursday as an 145 kt 250 hPa
jet streak moves across the region. This will create an ageostrophic
response (i.e. acceleration) and cause some synoptic lift across the
forecast area of responsibility. On top of that, the models indicate
low level 285 Kelvin isentropic lift on top of the cold airmass. The
GFS is the oddball out and was ignored as it did not match ensemble
mean nor the aforementioned consensus in the deterministic runs. Will
have to watch for a sneaky snow advisory snow amount being met. One
fly in the ointment is that the low levels are very dry (as expected
with an Arctic intrusion), so this could reduce probabilities for more
significant precipitation measurement. Of course, not ready to buy into
the thermodynamic profiles (particularly the NAM) this far out, but
did trend with higher pops, qpf, and lower temperatures. If a snow pack
does come into fruition, the minimums into Friday morning will have
to be watched as they could bottom into negative territory. Otherwise,
midweek will be cold and have gone with bias corrected mos guidance.
Friday and beyond:
Friday through Saturday will feature a precipitation free forecast as
the region will be between synoptic systems. The next chance of precipitation
in the form of snow will be on Sunday as another trof digs across the
central Rockies and eventually ejects out across the prairies. It is
too early to hammer out details this far out and have stuck with the
weighted blend solution. Temperatures will continue to remain below
normal.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1106 AM CST TUE DEC 3 2013
NAM, and HRRR were both in generally good agreement with the
timing of a cold front as it crosses western Kansas early this
evening. As this front passes, southerly winds at less than 10kts
will shift to the north and increase into the 20 to near 25 kt
range for several hours. Based on the latest model runs of the
HRRR and NAM the wind shift is expected to occur around 00z at
HYS. The wind shift is expected between 02z and 05z at DDC and
GCK. In addition to the gusty north winds following the frontal
passage MVFR status is expected to spread south across western
Kansas overnight. Based on surface observations at 16z north of
this front in Nebraska and bufr soundings the cloud bases are
expected to range from 1000 to 1500 feet.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 21 28 10 13 / 0 0 10 50
GCK 21 26 11 12 / 0 0 30 50
EHA 21 29 7 13 / 0 10 30 50
LBL 23 29 13 13 / 0 0 10 50
HYS 21 28 9 17 / 0 0 20 10
P28 29 35 14 19 / 0 0 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Sugden
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
132 PM CST Tue Dec 3 2013
...Update to long term discussion...
.SYNOPSIS...
ISSUED AT 1106 AM CST TUE DEC 3 2013
At 12z Tuesday a -35c 500mb low was located over Idaho/western
Montana. A +100kt 300mb jet streak was located in the based of
this upper low and extended from northern Nevada into southern
Wyoming. 700 mb level difluent flow appears to be located across
eastern Wyoming. This was located near the left exit region of
the 300mb jet. Across the Central Plains earlier this morning the
850mb temperatures ranged from +10C at North Platte to +15c at
Amarillo. Dodge City this morning had a 850mb temperature of +13c.
A surface cold front was located across Nebraska at 12z Tuesday.
North of this surface cold front low clouds, gusty north winds and
light snow/fog were observed from the surface observations across
eastern Wyoming and northwest Nebraska. Surface temperatures under
the status were mainly in the 20s. 850mb temperatures north of
this front varied from -9c at South Dakota to -13c at Glasgow MT.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 349 AM CST TUE DEC 3 2013
Low level moisture was slowly advecting northward into south central
and southeast Kansas early this morning. This was manifesting itself
as areas of locally dense fog across north central Oklahoma into
southeast Kansas. The High Resolution Rapid Refresh model is
suggesting that fog could be developing into the Medicine Lodge and
Pratt areas by around sunrise and continue into this morning before
burning off. Will add some areas of locally dense fog to the gridded
forecast for a few hours this morning
The upper low and trough over the northern Rockies will continue to
dig south and southeast today. All of the 00z models have slowed the
passage of the front across western Kansas from previous runs. Ahead
of the front, westerly winds will develop today across far southwest
Kansas. This will likely help boost temperatures to near or around
70 in locations from Johnson and Elkhart to around Liberal. Have
raised high temperatures several degrees in that area as well as a
few degrees more around Garden City and Dodge City. With less of a
downslope component expected over central and south central Kansas,
highs should top out in the low to mid 60s.
The cold front should be moving to a position along I-70 by sunset
and then continuing south through the remainder of south central and
southwest Kansas by around or shortly after midnight. Gusty north
winds will develop tonight and there could be a period of time
behind the front that winds are approaching or meeting advisory
criteria. For now will let the next shift assess any need for wind
headlines tonight. Colder air and stratus will push south across
western Kansas overnight. Temperatures should range from around 20
over west central and far southwest Kansas to the mid 20s over south
central Kansas.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 132 PM CST TUE DEC 3 2013
Wednesday night/Thursday:
The 03.012Z ECMWF, NAM, and GEM were indicating the potential for some
snow Wednesday night but mainly into Thursday as an 145 kt 250 hPa
jet streak moves across the region. This will create an ageostrophic
response (i.e. acceleration) and cause some synoptic lift across the
forecast area of responsibility. On top of that, the models indicate
low level 285 Kelvin isentropic lift on top of the cold airmass. The
GFS is the oddball out and was ignored as it did not match ensemble
mean nor the aforementioned consensus in the deterministic runs. Will
have to watch for a sneaky snow advisory snow amount being met. One
fly in the ointment is that the low levels are very dry (as expected
with an Arctic intrusion), so this could reduce probabilities for more
significant precipitation measurement. Of course, not ready to buy into
the thermodynamic profiles (particularly the NAM) this far out, but
did trend with higher pops, qpf, and lower temperatures. If a snow pack
does come into fruition, the minimums into Friday morning will have
to be watched as they could bottom into negative territory. Otherwise,
midweek will be cold and have gone with bias corrected mos guidance.
Friday and beyond:
Friday through Saturday will feature a precipitation free forecast as
the region will be between synoptic systems. The next chance of precipitation
in the form of snow will be on Sunday as another trof digs across the
central Rockies and eventually ejects out across the prairies. It is
too early to hammer out details this far out and have stuck with the
weighted blend solution. Temperatures will continue to remain below
normal.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1106 AM CST TUE DEC 3 2013
NAM, and HRRR were both in generally good agreement with the
timing of a cold front as it crosses western Kansas early this
evening. As this front passes, southerly winds at less than 10kts
will shift to the north and increase into the 20 to near 25 kt
range for several hours. Based on the latest model runs of the
HRRR and NAM the wind shift is expected to occur around 00z at
HYS. The wind shift is expected between 02z and 05z at DDC and
GCK. In addition to the gusty north winds following the frontal
passage MVFR status is expected to spread south across western
Kansas overnight. Based on surface observations at 16z north of
this front in Nebraska and bufr soundings the cloud bases are
expected to range from 1000 to 1500 feet.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 21 29 10 13 / 0 0 10 50
GCK 21 27 11 12 / 0 0 30 50
EHA 21 27 7 13 / 0 10 30 50
LBL 23 30 13 13 / 0 0 10 50
HYS 21 29 9 17 / 0 0 20 10
P28 29 36 14 19 / 0 0 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Gerard
LONG TERM...Sugden
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1110 AM CST Tue Dec 3 2013
...Updated Synopsis and Aviation discussion...
.SYNOPSIS...
ISSUED AT 1106 AM CST TUE DEC 3 2013
At 12z Tuesday a -35c 500mb low was located over Idaho/western
Montana. A +100kt 300mb jet streak was located in the based of
this upper low and extended from northern Nevada into southern
Wyoming. 700 mb level difluent flow appears to be located across
eastern Wyoming. This was located near the left exit region of
the 300mb jet. Across the Central Plains earlier this morning the
850mb temperatures ranged from +10C at North Platte to +15c at
Amarillo. Dodge City this morning had a 850mb temperature of +13c.
A surface cold front was located across Nebraska at 12z Tuesday.
North of this surface cold front low clouds, gusty north winds and
light snow/fog were observed from the surface observations across
eastern Wyoming and northwest Nebraska. Surface temperatures under
the status were mainly in the 20s. 850mb temperatures north of
this front varied from -9c at South Dakota to -13c at Glasgow MT.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 349 AM CST TUE DEC 3 2013
Low level moisture was slowly advecting northward into south central
and southeast Kansas early this morning. This was manifesting itself
as areas of locally dense fog across north central Oklahoma into
southeast Kansas. The High Resolution Rapid Refresh model is
suggesting that fog could be developing into the Medicine Lodge and
Pratt areas by around sunrise and continue into this morning before
burning off. Will add some areas of locally dense fog to the gridded
forecast for a few hours this morning
The upper low and trough over the northern Rockies will continue to
dig south and southeast today. All of the 00z models have slowed the
passage of the front across western Kansas from previous runs. Ahead
of the front, westerly winds will develop today across far southwest
Kansas. This will likely help boost temperatures to near or around
70 in locations from Johnson and Elkhart to around Liberal. Have
raised high temperatures several degrees in that area as well as a
few degrees more around Garden City and Dodge City. With less of a
downslope component expected over central and south central Kansas,
highs should top out in the low to mid 60s.
The cold front should be moving to a position along I-70 by sunset
and then continuing south through the remainder of south central and
southwest Kansas by around or shortly after midnight. Gusty north
winds will develop tonight and there could be a period of time
behind the front that winds are approaching or meeting advisory
criteria. For now will let the next shift assess any need for wind
headlines tonight. Colder air and stratus will push south across
western Kansas overnight. Temperatures should range from around 20
over west central and far southwest Kansas to the mid 20s over south
central Kansas.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 410 AM CST TUE DEC 3 2013
Medium range models indicate a strong upper level trough moving east
across the Intermountain West Wednesday and Thursday while a series
of H5 vort maxes eject out of the trough axis northeast across the
Western High Plains. This will set up the chance for periods of
light precip across portions of western Kansas late Wednesday night
into Thursday. As the elongated upper level trough approaches, an
upper level jet exiting the trough axis will intensify as it climbs
northeast across the Western High Plains reaching speeds in excess
of 130kt by early Thursday morning. Additionally, increased H7
frontogenesis banding is noted migrating across western Kansas
during this same general time frame. Meanwhile, GFS/ECMWF model
soundings show mid/upper level moisture advection into western
Kansas with profiles saturating by early to mid morning Thursday.
Due to this, periods of light snow will be possible across west
central and southwest Kansas late Wednesday night with those
chances spreading eastward into central Kansas Thursday. However,
significant snow accumulations are not expected with model soundings
indicating pw values well under half an inch. Drier conditions are
expected Friday through Saturday afternoon as the upper level wave
opens up and kicks off to the east while another upper level trough
begins to drop south across the Pacific Northwest early in the
weekend.
Temperatures will be below normal Wednesday as cold air surges
southward into western Kansas in wake of a strong cold front pushing
across the region Tuesday afternoon/evening. The NAM/GFS show the
H85 0C isotherm dipping south into the Texas panhandle by mid day
Wednesday while extending back to the northeast into south central
Kansas. As a result, highs are expected to be reached earlier in the
day ranging from the 20s(F) across west central Kansas to the 30s(F)
in south central Kansas. Temperatures will be frigid Thursday and
Friday as the arctic air mass settles into western Kansas with H85
temperatures reaching as low as 15C below. Look for highs only up
into the teens(F) and 20s(F) Thursday and Friday with a gradual
warming trend going into the weekend as the cold air mass begins to
slowly erode.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1106 AM CST TUE DEC 3 2013
NAM, and HRRR were both in generally good agreement with the
timing of a cold front as it crosses western Kansas early this
evening. As this front passes, southerly winds at less than 10kts
will shift to the north and increase into the 20 to near 25 kt
range for several hours. Based on the latest model runs of the
HRRR and NAM the wind shift is expected to occur around 00z at
HYS. The wind shift is expected between 02z and 05z at DDC and
GCK. In addition to the gusty north winds following the frontal
passage MVFR status is expected to spread south across western
Kansas overnight. Based on surface observations at 16z north of
this front in Nebraska and bufr soundings the cloud bases are
expected to range from 1000 to 1500 feet.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 68 21 29 10 / 0 0 0 20
GCK 67 21 27 9 / 0 0 0 30
EHA 68 21 27 11 / 0 0 0 30
LBL 71 23 30 12 / 0 0 0 30
HYS 62 21 29 10 / 0 0 0 20
P28 66 29 36 16 / 0 0 0 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Gerard
LONG TERM...JJohnson
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS PADUCAH KY
844 PM CST Wed Dec 4 2013
.UPDATE...
ISSUED AT 836 PM CST WED DEC 4 2013
Used the latest HRRR model to update wind and temperature fields
tonight as the front is just a tad faster but temperatures really
drop right behind the front. Otherwise forecast looks on track
with a few showers developing southwest of IND. This precipitation
should increase and spread southwest into our area later this
evening. New NAM is still a bit faster than other models with the
onset of freezing rain by about 3 hours but will not make any
changes at this point.
&&
.SHORT TERM...(This Evening through Friday Night)
ISSUED AT 334 PM CST WED DEC 4 2013
The 12Z models have sped up the arrival of the surface freezing
line, which is currently well past Kansas City and trucking this
way. The other trend is for a cooler overall solution, with many
areas quickly changing to sleet as the cold air arrives and then
quite a period of pure snow, especially across southern Illinois
and southeast Missouri.
Given that impacts now appear likely across southeast Missouri and
southern Illinois by late Thursday afternoon, will go ahead and
upgrade to a Winter Storm Warning at this time. Far northwest
areas will begin at 3 PM Thursday, and most of the area will begin
at 6 PM. The far southeast 4 counties of west Kentucky will not
start until Midnight Thursday Night, and some of that area may
not see problems until after daybreak. It will be a close call
down there for Friday morning.
Given the copious liquid equivalent precipitation forecast, there
will be the potential for 1/4 to 1/2 inch of icing, mainly over
west Kentucky and the Missouri Bootheel. Much of southeast
Missouri, southern Illinois and southwest Indiana will see mainly
sleet and snow with some locations receiving as much as a half a
foot before it is done. The precipitation should end as light snow
from west to east Friday afternoon and evening. An inch of snow
may still fall 00Z-03Z Saturday in the far southeast, so will
continue the Warning down there until 03Z.
In the meantime, it will be quite mild tonight ahead of the cold
front, and some scattered showers and maybe a thunderstorm or two
will be possible mainly over the bootheel and west Kentucky
overnight tonight.
.LONG TERM...(Saturday through Wednesday)
ISSUED AT 334 PM CST WED DEC 4 2013
Dry and chilly conditions are expected Saturday as high pressure
briefly settles over the northern U.S. As the high moves north, low
pressure will slide northeast from the western Gulf of Mexico,
skirting eastern portions of the PAH FA Sunday into Sunday night.
With cold air already in place, moisture pushed northward by this
weather system will be a wintry mix. ECMWF takes the low a bit
farther east than yesterday, and thus has backed off a bit on QPF.
GFS still shows significant moisture across our region late Saturday
night into Sunday. In either case, best moisture will be across
west Kentucky. Soundings continue to indicate a wintry mix, but
while yesterday`s run showed a majority freezing rain, today looks
more like an even mixture of freezing rain and sleet across west
Kentucky into southern portions of southeast Missouri. Farther
north and west, where temperatures will be colder and QPF will be
significantly lower, precipitation will be mainly light snow and
sleet.
Wintry precipitation is expected to transition to rain by Sunday
afternoon from the Pennyrile region west to the Land Between the
Lakes region in west Kentucky as temperatures climb a little above
freezing. This will help negate more significant ice accumulations.
Overall confidence is still not very high due to model
discrepancies, so kept snow and ice amounts fairly low for now.
Moisture is not as deep as our upcoming late work week system and is
moving more quickly, so amounts should not be as high as our first
system. However, if the late week system leaves us with snow/ice
coverage, this could have a big impact on our surface temps and lead
to more accumulation of whatever falls.
Precipitation will taper off from west to east Sunday night into
Monday, with just a small chance of light snow or sleet lingering in
our eastern counties on Monday. Any additional accumulations during
this time period will be light. Behind this weather system, the big
story will be bitterly cold temperatures. Monday highs will still
be in the upper 20s to middle 30s, which is 15 to 20 degrees below
seasonal normals. By Monday night, lows will be in the upper single
digits to middle teens, and then even a few degrees colder Tuesday
night, which would put us around 25 degrees below normal. Wind
chills around zero will be possible both Monday night and Tuesday
night across some of our northern counties.
&&
.AVIATION...
ISSUED AT 542 PM CST WED DEC 4 2013
With the approach of a frontal system, cigs/vsbys will slowly
deteriorate from northwest to southeast through the valid period.
All sites should remain VFR through at least 04Z, then decrease to
MVFR with the potential of briefly improving to VFR in the 14-21Z
time frame. VCSH possible at KCGI 09-14Z, then FZRA from 19Z on.
At KPAH/KEVV/KOWB VCSH possible after 07Z, -RA between 09-15Z,
then -RA again after 19-21Z. Southerly winds 10-15 mph will veer
around to the northwest and gust up to 15-20 mph behind the
frontal passage.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING from 6 PM Thursday to 6 PM CST Friday FOR
ILZ077-078-083-086-087-089>091-093-094.
WINTER STORM WARNING from 3 PM Thursday to 6 PM CST Friday FOR
ILZ075-076-080>082-084-085-088-092.
MO...WINTER STORM WARNING from 6 PM Thursday to 6 PM CST Friday FOR
MOZ112-114.
WINTER STORM WARNING from 3 PM Thursday to 6 PM CST Friday FOR
MOZ076-086-087-100-107>111.
IN...WINTER STORM WARNING from 6 PM Thursday to 6 PM CST Friday FOR
INZ081-082-085>088.
KY...WINTER STORM WARNING from 6 PM Thursday to 6 PM CST Friday FOR
KYZ001>008-010-011-013>016-018>020.
WINTER STORM WARNING from Midnight Thursday Night to 9 PM CST
Friday FOR KYZ009-012-017-021-022.
&&
$$
UPDATE...PS
AVIATION...JP
SHORT TERM...DRS
LONG TERM...RT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
623 PM EST WED DEC 4 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 400 PM EST WED DEC 4 2013
20Z SFC CHART INDICATES ELONGATED SFC TROUGH FROM WCNTRL WI INTO
NORTHEAST IA WITH MSLP OF 998MB. WV AND RUC FCST SHOWS SHORTWAVE
PUSHING ACROSS SOUTHERN MINNESOTA. WAVE IS EXPECTED TO LIFT TOWARD
NORTHWEST WI WHILE DEEPENING OVERNIGHT. WARM AIR ADVECTION IN FULL
SWING AHEAD OF MAINLY 850MB LOW LIFTING INTO NW WISCONSIN. RUC13 AND
NAM12 HAVE DONE NICE JOB WITH THE WARM LAYER AT H9-H85 TODAY AND
BOTH SHOW H85 TEMPS OVER 2C REACHING NORTH OF ALL CWA BY 00Z.
SOUNDINGS OVER US CURRENTLY WOULD SUGGEST MAINLY FZRA BUT LINGERING
COLD POCKET NEAR SFC /TEMPS STILL IN MID-UPR 20S/ IS ALLOWING SLEET
TO HANG ON LONGER. CURRENTLY SNOW IS STILL FALLING OVER KEWEENAW
PENINSULA BUT IS EVEN STARTING TO MIX WITH FREEZING RAIN AND SLEET
OVER PORTIONS OF WESTERN UPR MICHIGAN. PLAN FOR EVENING IS THAT
MIXED FREEZING RAIN/SLEET/SNOW WILL CHANGE TO MAINLY FREEZING RAIN
AND SLEET WHILE MOSTLY FREEZING RAIN OR EVEN JUST RAIN OCCURS FOR
CNTRL CWA...ESPECIALLY CLOSER TO LK MICHIGAN SHORE. IF HEAVIER
PRECIP WAS EXPECTED OVR CNTRL THIS EVENING...ICING COULD BE BIGGER
ISSUE. RIGHT NOW...APPEARS THAT HEAVIER PRECIP IS GOING TO OCCUR IN
STRIPE FROM SOUTHERN MINNESOTA TOWARD WESTERN LK SUPERIOR IN AREAS
OF STRONGEST PVA/DIVERGENCE ALOFT JUST AHEAD OF TRACK OF SHORTWAVE.
GIVEN TREND TO MORE FZRA THOUGH...INCREASED ICE ACCUMS OVER INTERIOR
WEST AND CNTRL TO 0.10-0.20 INCHES THROUGH THE EVENING.
AS MID-LEVEL DRYING IN THE H7-H6 LAYER ARRIVES 03Z-06Z OVER THE
SOUTH AND AFTER 06Z IN THE NORTH...EXPECT WINTRY MIX OF PRECIP TO
TAPER OFF TO MORE OF A DRIZZLE/FREEZING DRIZZLE. ACTUALLY HEADLINES
SO FAR ARE WORKING OUT PRETTY WELL. DID HAVE TO GO WITH MORE SLEET
AND FREEZING RAIN AS WARM AIR WORKED IN QUICKER...BUT OVERALL IDEA
OF WINTRY MIX IS COVERED WITH GOING WINTER WEATHER ADVY. TIMING FOR
ENDING OF ADVY SEEMS GOOD AS WELL. ONLY POSSIBLE TROUBLE SPOTS WILL
IN THE INTERIOR CNTRL AND EAST THIS EVENING DUE TO ICING IF HEAVIER
PRECIP ENDS UP BLOSSOMING TO THE EAST OF PRIMARY SHORTWAVE. SOME
SHORT TERM HIGHER-RES MODELS INDICATE EXPANSION OF PRECIP OVER
SCNTRL THIS EVENING...BUT RADAR TRENDS UPSTREAM NOT REALLY SHOWING
THIS. IF SFC TEMPS STAY BLO FREEZING THAT AREA WILL NEED TO BE
WATCHED FOR POSSIBLE ADVY.
NOW ONTO LATE TONIGHT AND THURSDAY. MAIN ISSUE SEEMS TO BE LK EFFECT
AND BLOWING SNOW ON THE KEWEENAW. WEST WINDS MAY GUST OVER 40 MPH AT
TIMES LEADING TO THE BLSN/POOR VISIBILITY...PROBABLY 1/4-1/2SM AT
TIMES OVER PORTIONS OF THE KEWEENAW. LARGER SCALE FORCING BECOMES
NEGATIVE BUT THERE IS A LOT OF LINGERING MOISTURE BLO H8 WITH
COOLING AT INVERSION TOP TO -16C OR SO BY MIDDAY. GIVEN LK SUPERIOR
WATER TEMPS AROUND 3-4C THIS GIVES MORE THAN SUFFICIENT OVER-WATER
INSTABILITY FOR AT LEAST MODERATE LK EFFECT SNOW SHOWERS. WSW WINDS
OVER LAND WITH MORE OF A WESTERLY WIND OVER LK SUPERIOR INDICATES
STRONGER CONVERGENCE AREA SETS UP ACROSS KEWEENAW. SNOW AMOUNTS WILL
BE HELD DOWN SOME BY LOWER SLR/S AS THERE IS A LOT OF FRACTURING OF
SNOWFLAKES DUE TO THE STRONG WINDS. EXPECT ADVY LEVEL SNOWS OF 3-5"
OR 4-7" WITH A LOT OF WIND/BLSN. WILL ISSUE A SEPARATE LAKE EFFECT
SNOW ADVY FOR LATE TONIGHT THROUGH THURSDAY...GOING INTO PLACE RIGHT
WHEN THE CURRENT WINTER WEATHER ADVY FOR THE MESSY MIX OF SNOW/SLEET
AND FREEZING RAIN DIMINISHES.
AND FINALLY FOR LATE TONIGHT INTO THURSDAY...AWAY FM THE
KEWEENAW...MAIN ISSUE WILL BE COLD AIR PUSHING IN FM THE WEST.
ALREADY SEEING THIS ARCTIC AIR POURING ACROSS THE DAKOTAS THIS AFTN.
EXPECT SLOWLY FALLING TEMPERATURES THROUGH THE DAY AS THE COLD WORKS
EAST...WITH READINGS LIKELY INTO THE UPPER SINGLE DIGITS BY EVENING
OVER THE FAR WEST CWA. THIS COLDER AIR WILL ALSO FREEZE ANY
LINGERING SLUSH AND WATER IS ON THE ROADS AND SIDEWALKS...WHICH
COULD RESULT IN TOUGHER TRAVEL CONDITIONS IN SPOTS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 456 PM EST WED DEC 4 2013
THE EASY PART OF THIS FCST PERIOD WILL BE THE LACK OF MIXED
PRECIPITATION. EXPECT ONLY SNOW...WITH SFC TEMPS MAXING OUT IN THE
LOW TO MID 20F DEGREE RANGE /MONDAY/ AND 850MB TEMPS TOPPING OUT
AROUND -15C EAST EARLY THURSDAY NIGHT...AND AGAIN SUNDAY THROUGH
MONDAY AROUND -12 TO -15C.
WILL CONTINUE TO HAVE LES OVER THE W HALF OF UPPER MI THURSDAY
NIGHT. AMOUNTS ARE STILL IN QUESTION. MAY NEED TO EXTEND THE CURRENT
LES ADVISORY FOR ANOTHER 6-12HRS IF THE 3-5IN OF SNOW FALL OVER
KEWEENAW...N HOUGHTON...AND FAR W ONTONAGON COUNTY THURSDAY NIGHT.
THE LES PARAMETER OFF THE GFS REMAINS AT OR ABOVE 2 THROUGH 06Z
FRIDAY. WILL LET LATER SHIFTS DISCUSS THE NEED...AS THE WINDS
DIMINISH SIGNIFICANTLY...BUT STILL GUSTING TO AROUND 20-25KTS
OVERNIGHT. THE WEAKENING SFC TROUGH WILL LINGER ACROSS THE UPPER
GREAT LAKES THROUGH SATURDAY...WITH WINDS SLOWLY MOVING MORE
OFFSHORE SATURDAY NIGHT. UNTIL THEN...LES WILL LINGER MAINLY ACROSS
THE KEWEENAW PENINSULA.
KEPT MENTION OF THE COLDEST TEMPS OF THE SEASON IN THE HWO FOR
THURSDAY NIGHT THROUGH SATURDAY MORNING. AT THIS POINT IT LOOKS LIKE
A WIND CHILL ADVISORY MAY NOT BE NEEDED FOR FRIDAY NIGHT INTO
SATURDAY MORNING...AS THE LOWEST VALUES FLIRT WITH -25C OVER THE SW
CORNER OF THE CWA.
STRONG SFC HIGH OVER SW CANADA FRIDAY WILL PUSH ACROSS THE NORTHERN
AND CENTRAL PLAINS FRIDAY NIGHT INTO EARLY SATURDAY...BEFORE
BUILDING ACROSS THE GREAT LAKES REGION. ENDED UP SPLITTING UP SOME
OF THE MORE EXTENDED POPS AS A RESULT...FOR SATURDAY THROUGH SUNDAY.
THE NEXT ROUND OF SNOW WILL SLIDE BACK IN SUNDAY NIGHT...WITH LIKELY
POPS OVER THE E HALF...AS THE HIGH EXITS ACROSS THE NEW ENGLAND
STATES AND LOW PRESSURE NEARS FROM THE LOWER AND CENTRAL MS VALLEY.
THE SFC LOW LOOKS TO CROSS LAKE HURON AROUND 12Z MONDAY...DEEPENING
AS IT MOVES TO S QUEBEC MONDAY AFTERNOON/EVENING. THIS WILL BRING
ABOUT ANOTHER ROUND OF W TO NW WINDS...WITH GALES AGAIN POSSIBLE
ACROSS LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 623 PM EST WED DEC 4 2013
A LOW PRESSURE SYSTEM WILL KEEP PRECIP AT THE TAF SITES INTO
TONIGHT. WARM AIR MOVING INTO THE REGION WILL SWITCH FREEZING RAIN
THIS EVENING BACK TO SNOW LATER TONIGHT AT ALL SITES. LOTS OF
DIFFICULTY FORECASTING EXACT CHANGE OVER TIMES...SO PUT BEST GUESS
INTO TAFS. PRECIP WILL CHANGE BACK TO SNOW TONIGHT AS COLD AIR COMES
IN BEHIND A COLD FRONT...WHILE PRECIP TRANSITIONS FROM AREA WIDE
PRECIP TO LAKE EFFECT SNOW...FAVORING IWD AND ESPECIALLY CMX INTO
THURSDAY. USED CONSENSUS GUIDANCE FOR CIGS/VIS AND MORE CLIMATOLOGY
FOR LAKE EFFECT SNOW LATE IN THE PERIOD. LIFR CONDITIONS WILL
IMPROVE TONIGHT AT ALL SITES AS PCPN BEGINS TO MOVE OUT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 317 PM EST WED DEC 4 2013
LOW PRESSURE OVER WISCONSIN WILL DEEPEN ACROSS CENTRAL AND EASTERN
LAKE SUPERIOR OVERNIGHT...AND EXIT NORTHEAST ACROSS JAMES BAY WHILE
FURTHER DEEPENING THURSDAY NIGHT. THE PERIOD OF STRONG WINDS WILL
CONTINUE THROUGH THURSDAY NIGHT...WITH OUR INITIAL E TO NE WINDS
/GALES TO 35KTS OVER W LAKE SUPERIOR/ BECOMING OUT OF THE S AND SW
FOR ALL BUT FAR W LAKE SUPERIOR OVERNIGHT...BEFORE W GALES OF 35 TO
40 KNOTS START UP THURSDAY MORNING THROUGH THURSDAY NIGHT.
A STRONG ARCTIC HIGH PRESSURE SYSTEM OVER WESTERN CANADA ON THURSDAY
WILL SLIDE ACROSS THE NORTHERN PLAINS ON SATURDAY...AND ACROSS THE
GREAT LAKES SUNDAY. THE HIGH WILL EXIT ACROSS THE NEW ENGLAND STATES
WHILE WEAKENING SLIGHTLY ON MONDAY. EXPECT LOW PRESSURE OVER THE
LOWER MISSISSIPPI VALLEY SUNDAY TO DEEPEN AND SURGE NORTHWARD ACROSS
LAKE HURON LATE SUNDAY NIGHT INTO MONDAY. W TO NW GALES TO 35KTS
WILL BE POSSIBLE AGAIN MONDAY THROUGH TUESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 AM EST /MIDNIGHT CST/ THURSDAY
FOR MIZ002-004-005-009>011-084.
LAKE EFFECT SNOW ADVISORY FROM 4 AM TO 7 PM EST THURSDAY FOR
MIZ001-003.
WINTER WEATHER ADVISORY UNTIL 4 AM EST THURSDAY FOR MIZ001-003.
LAKE SUPERIOR...
GALE WARNING FROM 6 AM THURSDAY TO 4 AM EST FRIDAY FOR
LSZ265>267.
GALE WARNING UNTIL 4 AM EST FRIDAY FOR LSZ263-264.
GALE WARNING FROM 8 AM TO 7 PM EST THURSDAY FOR LSZ246>248-250-
251.
GALE WARNING FROM 5 AM EST /4 AM CST/ TO 7 PM EST /6 PM CST/
THURSDAY FOR LSZ241>245.
GALE WARNING UNTIL 10 PM EST /9 PM CST/ THURSDAY FOR LSZ162.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...KF
AVIATION...07
MARINE...KF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1248 PM EST TUE DEC 3 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 341 AM EST TUE DEC 3 2013
A WARM FRONT MOVING THROUGH LOWER MICHIGAN WILL BRING LIGHT SNOW
POSSIBLY MIXED WITH SLEET AND FREEZING RAIN THIS MORNING. WE DON/T
EXPECT MUCH IF ANY ACCUMULATION. HOWEVER A FEW ROADS COULD BECOME
SLICK. THE PCPN WILL BECOME LIGHT RAIN THIS AFTERNOON AS WARMER AIR
MOVES INTO THE REGION.
A STRONG COLD FRONT WILL MOVE THROUGH WEDNESDAY NIGHT BRINGING AN
ABRUPT END TO THE 50 DEGREE TEMPERATURES EXPECTED WEDNESDAY. SNOW
SHOWERS AND HIGHS IN THE 20S ARE EXPECTED FRIDAY THROUGH THE
WEEKEND.
&&
.UPDATE...
ISSUED AT 1154 AM EST TUE DEC 3 2013
I UPDATED THE GRIDS TO KEEP THE CHANCE OF FREEZING RAIN GOING INTO
THE EVENING NEAR ROUTE 10...EAST OF US-131 (OVER THE HIGHER
TERRAIN AREAS). ALSO I INCREASED THE CHANCE OF RAIN OVER SOUTHERN
AREAS ANOTHER SHORTWAVE HEADS INTO THE AREA THIS AFTERNOON. THIS
IS SEEN NICELY ON BOTH THE WATER VAPOR AND IR IMAGE LOOPS FROM MN
TO WI INTO IL AT 11 AM. AS THAT MOVES NORTH AND EAST IT SHOULD
SHOULD KEEP THE RAIN GOING NORTH OF ROUTE 2O INTO THE LATE
EVENING HOURS BUT ALLOW THE RAIN SHOULD END FOR AWHILE OVER AREAS
NEAR AND SOUTH OF I-96.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
FORECAST CONCERNS DEAL WITH MIXED PCPN MAINLY THIS MORNING.
LATEST RADAR SHOWS A BAND OF PCPN STRETCHING FROM OCEANA COUNTY
SOUTHEAST TOWARD NW OHIO MOVING NEED THROUGH THE CWA. MOST OF THIS
IS LIGHT SHOW BUT LOCAL OBS HAVE SHOWN SOME SLEET TOO. THIS WAS
CORROBORATED BY DUAL POL. LATEST HRRR AND FCST SOUNDINGS SUGGEST
SOME
LIGHT FREEZING RAIN IS POSSIBLE TOO THIS MORNING BEFORE TEMPS WARM
UP ENOUGH TO RESULT IN LIGHT RAIN. PCPN IS FAIRLY LIGHT AND ANY
ACCUMS SHOULD REMAIN LESS THAN AN INCH. THAT SAID...A FEW ROADS MAY
BECOME SLICK.
A WARM FRONT WILL CONTINUE TO PUSH NORTH THROUGH THE CWA TONIGHT. H8
TEMPS RISING TO 7C SHOULD RESULT IN SFC TEMPS IN THE 50S TOMORROW.
MODELS CONTINUE TO BE AT ODDS ON COLD FRONTAL TIMING. WE/LL BE
CONSISTENT THOUGH IN FOLLOWING THE SLOWER ECMWF DUE TO THE OCCLUDING
NATURE OF THE SYSTEM. THAT MEANS A FROPA WEDNESDAY NIGHT. HIGHS
THURSDAY WILL BE IN THE MID 30S. LIGHT SNOW SHOWERS POSSIBLE
THURSDAY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
TWO MAIN HEADLINES OF THE LONG TERM REMAIN THE COLD AND LAKE EFFECT
SNOW SHOWERS. THE COLD MAY BE THE BIGGER STORY AS THE LAKE EFFECT
LOOKS TO BE SOMEWHAT MOISTURE DEPLETED.
COLD AIR ADVECTION WILL BE IN FULL SWING THURSDAY NIGHT AS WE BEGIN
THE LONG TERM WITH THE LOW MOVING AWAY ACROSS ONTARIO. DELTA T/S
WILL BE IN THE MIDDLE TEENS...PROVIDING DECENT INSTABILITY. MOISTURE
LOOKS LIMITED SO NOT EXPECTING ANYTHING IN THE WAY OF SIGNIFICANT
LAKE EFFECT. MINOR ACCUMULATIONS AT BEST.
THAT REALLY REMAINS THE CASE FOR FRIDAY THROUGH SATURDAY. CONTINUED
COLD AIR ADVECTION WILL PUSH DELTA T/S INTO THE LOWER 20S C...BUT
MOISTURE REMAINS A LIMITING FACTOR. WE NEVER DEEPLY PLUNGE INTO
CYCLONIC FLOW TO THE NORTH SIDE OF THE UPPER JET AXIS...INSTEAD
REMAINING IN A BROAD SOUTHWEST TO WEST FLOW. 1000-700MB RH VALUES
FROM FRIDAY THROUGH SATURDAY REMAIN IN THE 40-60 PCT RANGE WHICH IS
NOT IDEAL. 20-40 PCT CHANCES FOR SNOW SHOWERS THURSDAY NIGHT THROUGH
SATURDAY SEEM WARRANTED. AT THIS POINT NOT EXPECTING ANY BIG
ACCUMULATIONS...JUST PERSISTENT LIGHT SNOW SHOWERS.
LOW PRESSURE IS FORECAST BY THE ECMWF (STILL THE MODEL OF CHOICE
TONIGHT) TO SWING NORTH THROUGH THE AREA SUNDAY NIGHT INTO MONDAY
WHICH BRINGS A GENERAL LIGHT SYNOPTIC SNOW TO THE AREA.
LOWS IN THE TEENS THROUGH THE PERIOD WITH HIGHS IN THE 20S WILL BE
COMMON. THIS IS COLDER THAN NORMAL...BUT BY NO MEANS RARE FOR EARLY
DECEMBER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1242 PM EST TUE DEC 3 2013
WITH A WARM FRONT ACROSS THE REGION PUSHING ONLY SLOWLY
NORTH...LOTS OF IFR CONDITIONS ALONG WITH RA/DZ WERE REPORTED FROM
THE TAF SITES. AS THIS FRONT WILL LINGER OVER THE AREA INTO
TONIGHT...THE LOW CONDITIONS WILL LIKELY PERSIST. SOME POCKETS OF
MVFR WILL BE POSSIBLE...BUT THEY SHOULD FILL IN QUICKLY SO THAT IS
NOT FEATURED IN THE FORECAST.
AS THE ARCTIC FRONT APPROACHES FROM THE WEST WED...THE LOW CLOUDS
WILL LIKELY LINGER. FOG COULD EVEN BECOME THICKER SENDING
CONDITIONS TO LIFR.
TEMPERATURES HAVE WARMED UP ENOUGH TO LIMIT THE RISK FOR SURFACE
BASED ICING AT KMKG...KGRR AND KLAN. HOWEVER JUST TO THE NORTH IN
PLACES LIKE KAMN AND KRQB ICING AND OR SNOW COULD CAUSE IMPACTS.
&&
.MARINE...
ISSUED AT 341 AM EST TUE DEC 3 2013
SOUTH TO SOUTHEAST WINDS WILL INCREASE TO 15 TO 25 KNOTS TODAY. THE
OFFSHORE NATURE OF THE WINDS SHOULD PRECLUDE WAVES FROM GETTING
HIGHER THAN 3 FEET.
&&
.HYDROLOGY...
ISSUED AT 341 AM EST TUE DEC 3 2013
NO HYDRO ISSUES TODAY. HOWEVER THE ARCTIC AIR EXPECTED BY THE END OF
THE WEEK COULD CAUSE ICE TO DEVELOP ON STREAMS AND RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...MJS
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1229 PM EST TUE DEC 3 2013
.UPDATE...
ISSUED AT 739 AM EST TUE DEC 3 2013
OPTED TO ADD SOME PATCHY -FZDZ TO THE FCST FOR LATER THIS MRNG/AFTN
FOR MUCH OF THE W HALF OF UPR MM WITH EXPECTATION THAT MID LVL
DRYING ASSOCIATED WITH DNVA/LARGER SCALE QVECTOR DVGC IN THE WAKE OF
DEPARTING SHRTWV WL DRY OUT THE DGZ LYR IN THE 10-12K FT RANGE. SFC
OBS IN NCENTRAL WI SHOW SOME OF THIS PCPN THERE...SO CONFIDENCE IS
INCREASED THIS WL HAPPEN AS WELL IN THE CWA WITH THE ONSET OF MID
LVL DRYING. EXCLUDED THIS PTYPE OVER THE FAR W WHERE LLVL E-SE FLOW
DOWNSLOPES/DRIES AND OVER THE E HALF WHERE LLVL DRY AIR HAS PROVEN
TO BE MORE RESILIENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 447 AM EST TUE DEC 3 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW RELATIVELY WEAK
ZONAL FLOW ALF OVER THE UPR GRT LKS TO THE N OF FASTER POLAR JET
OVER THE SRN 2/3 OF THE CONUS. THERE ARE 2 SHRTWVS OF NOTE EMBEDDED
IN THIS FLOW. THE FIRST IS MOVING E THRU MN AND CAUSING A BAND OF SN
EXTENDING FM NE MN SEWD OVER WRN LK SUP AND INTO CENTRAL WI AS OF
06Z UNDER AREA OF H85-5 QVECTOR CNVGC. THE AXIS OF HIER
REFLECTIVITIES IN WI APPEARS TO BE ORIENTED ALONG THE MOST
IMPRESSIVE ISENTROPIC ASCENT SHOWN ON THE 290K SFC /H7-75/...WHILE
THE MOST IMPRESSIVE RETURNS IN NE MN ALIGN WITH MOST VIGOROUS H85-5
QVECTOR CNVGC. THE 00Z INL/MPX RAOBS SHOW DEEP MSTR THRU THE DEPTH
OF THE TROP. ELY FEED OF DRIER LLVL AIR ASSOCIATED WITH AREA OF
MOCLR SKIES/HI PRES RDG AXIS STILL OVER FAR ERN UPR MI AND LOCATION
OF SHARPER H85 THERMAL PACKING/ISENTROPIC ASCENT TO THE S HAS SO FAR
LIMITED THE ENE EXTENT OF THE PCPN INTO UPR MI...BUT SN APPEARS
POISED TO SPREAD INTO THE WRN CWA PER LATEST SFC OBS/RADAR IMAGERY.
THE VSBY AT IWD FELL UNDER 2 MILES AT 07Z...AND THE VSBY AS CLOSE AS
ASHLAND IN NW WI IS DOWN TO 1/2 MILE. ENE FLOW DOWN WRN LK SUP MAY
BE ENHANCING THE SN INTO THIS AREA. IN THE AREA OVER WRN MN/MUCH OF
THE DAKOTAS UNDER DNVA/DEEP LYR QVECTOR DVGC BEHIND THE MN SHRTWV...
THERE IS LTL IF ANY PCPN FALLING EVEN THOUGH SKIES REMAIN CLDY WITH
QUITE A BIT OF MID LVL DRYING ABV LLVL MSTR SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. FARTHER TO THE W...THE 2ND MORE IMPRESSIVE
SHRTWV OF INTEREST IS MOVING EWD THRU THE NRN ROCKIES. 12HR H3 HGT
FALLS UP TO 200M AND H3 WIND SPEEDS UP TO 100M IN THE ACCOMPANYING
JET CORE ARE ASSOCIATED WITH THIS MORE IMPRESSIVE DISTURBANCE.
MAIN FCST CONCERNS IN THE SHORT TERM PERIOD ARE POPS/EXPECTED SN
ACCUMS THRU THIS MRNG ASSOCIATED WITH THE FIRST SHRTWV IN MN AND
NEED FOR ANY HEADLINES. FOCUS FOR TNGT TURNS TO POPS AND SN AMOUNTS
THAT WL ACCOMPANY THE APRCH OF THE 2ND STRONGER SHRTWV.
TODAY...AS MN SHRTWV TRACKS TO THE E INTO PERSISTENT SFC RDG AXIS
JUST TO THE E OF UPR MI AND AWAY FM TROF DEEPENING OVER THE W...
AREA OF H85-5 QVECTOR CNVGC IS PROGGED TO DIMINISH SGNFTLY BY 18Z
WITH MID LVL DRYING UNDER DVLPG H85-5 QVECTOR DVGC. EXPECT THE HIER
POPS THIS MRNG OVER THE W AND SCENTRAL UNDER THE SHARPER H85-5
QVECTOR CVNGC/SHARPER 295K ISENTROPIC ASCENT/AREA OF H85-7 FGEN.
GIVEN PRESENCE OF 2.5G/KG SPECIFIC HUMIDITY AT THIS LVL...EXPECT UP
TO 3 INCHES OF SN FOR THE 6-9 HR PERIOD OVER THE SW HALF OF THE CWA.
SINCE THE SN IS LIKELY TO FALL A FOR CLOSER TO 12Z HRS AT IWD...UP
TO 4 INCHES MAY ACCUMULATE THERE BEFORE THE PCPN DIMINISHES TOWARD
NOON. ALTHOUGH THE DGZ IS RATHER NARROW...MODELS SHOW FAIRLY
IMPRESSIVE OMEGA IN THIS LYR THAT MAY INCH SN/WATER RATIOS CLOSER
TO 15:1. CONSIDERING THE LO VSBYS REPORTED AT ASHLAND IN THE ABSENCE
OF LAKE ENHANCEMENT WITH THE LARGER SCALE E WIND...OPTED TO ISSUE A
WINTER WX ADVY FOR GOGEBIC COUNTY THRU MID MRNG. OTRW...UPSLOPE E
WIND OFF LK MI MAY CAUSE STEADIER SN TO LINGER LONGER OVER THE
SCENTRAL. SN WL LIKELY MOVE INTO THE E DURING THE AFTN BUT WL BE MUCH
LIGHTER AS THE DYNAMIC SUPPORT FADES AND HITS DRIER AIR.
TNGT...ALTHOUGH THE EARLY EVNG WL FEATURE DNVA/LARGER SCALE QVECTOR
DVGC LEFT IN THE WAKE OF THE DEPARTING/WEAKENING SHRTWV...FAVORED
CNDN MODEL SHOWS AXIS OF SHARPER H85-7 FGEN SUPPORTING BAND OF SN
NOW OVER SDAKOTA IMPACTING MAINLY THE SRN CWA FOR A COUPLE HRS IN
THE LATER EVNG. THE 00Z GFS/ECWMF SHOW A SIMILAR QPF...SO WENT FOR
HI END LIKELY POPS IN THIS AREA BY LATER IN THE EVNG. OVERALL MODEL
QPF UP TO 0.25 INCH WL SUPPORT A FEW INCHES OF SN IN THIS AREA. HIER
POPS/MORE SN MAY ARRIVE LATE OVER THE W AS THE DYNAMICS IN ADVANCE
OF THE SHRTWV MOVING THRU THE NRN ROCKIES PUSH TOWARD THE AREA. BUT
MODELS DISAGREE ON THE TIMING OF THE ARRIVAL OF THE DEEP LYR QVECTOR
CNVGC AS WELL AS INTENSITY OF THE SFC LO THAT MIGHT ACCOMPANY THE
LARGER SCALE FORCING. THE NAM/LOCAL WRF-ARW MODELS ARE THE MOST
AGGRESSIVE AT DEEPENING THE SFC LO AND BRINGING MORE PCPN FARTHER E.
BUT SINCE THE MAIN SHRTWV REMAINS SO FAR TO THE W THRU THE NGT...
SUSPECT THE SLOWER/WEAKER CNDN MODEL IS ON THE RIGHT TRACK. SO WENT
NO HIER THAN LIKELY POPS OVER THE FAR W FOR NOW. THE THERMAL FIELDS
FM THE CNDN MODEL INDICATE ENUF WARM AIR WL ARRIVE TO CAUSE THE SN
TO MIX WITH RA OVER THE FAR SCENTRAL.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 447 AM EST TUE DEC 3 2013
CONTINUED CHALLENGING FORECAST IN STORE FOR WEDNESDAY THROUGH
WEDNESDAY NIGHT TIME FRAME AS A WINTER WEATHER SYSTEM TAKES AIM AT
THE UPPER GREAT LAKES. VERY COLD AIR IS EXPECTED TO BUILD IN ON THE
BACK SIDE OF THIS SYSTEM ALLOWING FOR VERY COLD TEMPERATURES FRIDAY
NIGHT THROUGH SATURDAY NIGHT.
WEDNESDAY INTO WEDNESDAY NIGHT...SITUATION LOOKS A BIT BETTER FROM A
FORECASTING STANDPOINT AS MODELS ARE COMING INTO BETTER AGREEMENT
WITH RESPECT TO THE HANDLING OF THE LOW PRESSURE SYSTEM POISED TO
AFFECT THE AREA THROUGH THIS TIME PERIOD. THE 00Z RUN OF THE NAM AND
GFS ARE FINALLY ALIGNING BETTER WITH THE MORE CONSISTENT
EC/GEM...ALTHOUGH THEY ARE A TOUCH FASTER AT SHIFTING THE LOW INTO
THE UPPER PENINSULA. AS OF 12Z/04 EACH OF THE MODELS ARE IN GOOD
AGREEMENT IN PLACING THE SURFACE LOW OVER SW WISCONSIN WITH VERY
SIMILAR INTENSITIES. THE UPPER LEVEL 500MB CLOSED LOW IS PROGGED TO
BE POSITIONED FARTHER NORTHWEST OVER NORTHWESTERN MN...INDICATING
THE POTENTIAL FOR ADDITIONAL INTENSIFICATION OF THE SURFACE LOW. AT
THAT TIME ISENTROPIC UPGLIDE IS EXPECTED TO CONTINUE AS SHOWN BY
ANALYZING MOISTURE AND MOISTURE TRANSPORT ON A 295K PRESSURE
ISOSURFACE. SOUNDINGS AROUND 12Z/04 INDICATE THAT MOST OF THE
PRECIPITATION EAST OF A MQT TO IMT LINE WILL LIKELY BE IN THE FORM
OF RAIN AS A FAIRLY DEEP WARM LAYER EXISTS IN THE BOUNDARY LAYER.
WEST OF THAT LINE ATMOSPHERIC PROFILES ARE SUCH THAT THE
PRECIPITATION SHOULD REMAIN IN THE FORM OF SNOW. ALSO AT THIS TIME
FORCING IN THE DGZ SEEMS FAIRLY LIMITED...HOWEVER...THIS WILL CHANGE
THROUGH THE DAY. THE LOW IS PROGGED TO BE OVER SOUTH CENTRAL WI BY
18Z/04. AS THIS LOW CONTINUES TO APPROACH DURING THIS TIME PERIOD
INCREASED MOISTURE AND FORCING IN THE DGZ IS EXPECTED TO INCREASE
ALLOWING FOR A STEADY INCREASE IN SNOWFALL INTENSITY DURING THE
AFTERNOON HOURS. BETWEEN 00Z/05 AND 06Z/05 THE LOW IS PROGGED TO
SHIFT NORTH AND EASTWARD INTO THE EAST CENTRAL PORTION OF THE UPPER
PENINSULA. INCREASED SNOWFALL RATES ARE EXPECTED TO CONTINUE DURING
THAT TIME PERIOD AS WELL...AS CONTINUED MOISTURE AND LIFT ARE
PROGGED TO BE COLLOCATED IN THE DGZ AS SHOWN BY ANALYZING 1000-500MB
RH AS WELL AS QCONV IN THE 700-500 DGZ LAYER AS IDENTIFIED USING
ATMOSPHERIC PROFILES OF THE EC/GEM. THE WESTERN HALF OF THE UPPER
PENINSULA LOOKS TO ALSO BE IN A FAVORED LOCATION FOR HEAVY SNOWFALL
AS THIS REGION IS IN THE FAVORED LEFT EXIT REGION OF AN UPPER LEVEL
JET. THE MAIN CAVEAT HERE IS THE NEW UNCERTAINTY WITH PRECIPITATION
TYPE WHICH WAS INTRODUCED BY THE 00Z EC/GEM/UKMET WHICH PULLS THE
SURFACE LOW MUCH FARTHER TO THE WEST...WHICH TAKES THE LOW VERY NEAR
WHERE THE PREVIOUS GFS MODELS WERE TAKING IT OVER THE PAST COUPLE OF
DAYS. THIS WOULD SHIFT THE RAIN SNOW LINE FARTHER WEST...POSSIBLY
REDUCING SNOWFALL TOTALS. HAVE DECIDED TO CONTINUE WITH AN UPDATED
SPS BASED ON COORDINATION WITH SURROUNDING OFFICES...AS CONFIDENCE
IS NOT HIGH ENOUGH AT THIS POINT TO GO WITH A HEADLINE.
THURSDAY THROUGH SATURDAY...BETWEEN 12Z/05 AND 18Z/05 THE SURFACE
LOW IS PROGGED TO SHIFT NORTHEASTWARD TO JUST SOUTH OF JAMES
BAY...TAKEN THE BETTER SYNOPTIC FORCING OUT OF THE AREA. AT THE SAME
TIME A DEEP TROUGH DIGGING INTO THE NORTHERN PLAINS WILL BEGIN TO
INFLUENCE THE WEATHER IN THE UPPER PENINSULA. WINDS WILL BECOME
WESTERLY TO WEST NORTHWESTERLY IN THE RETURN FLOW ON THE BACK SIDE
OF THE LOW PRESSURE SYSTEM. THIS WILL ALLOW LAKE EFFECT SNOW DEVELOP
IN THE SNOWBELTS FAVORED WITH THE SAID WIND DIRECTION. 850MB
TEMPERATURES ARE EXPECTED TO DROP FROM NEAR -14C 12/05 TO AROUND
-22C 12Z/07. THESE TEMPERATURES ARE MORE THAN FAVORABLE FOR LES
GIVEN LAKE SURFACE TEMPERATURES AROUND 4C TO 5C...CREATING DELTA T
VALUES BETWEEN 18 AND 27 DEGREES THROUGH THIS TIME PERIOD.
WINDS...AGAIN...LOOK TO BE FAVORABLE WITH SURFACE TO 850MB WINDS
REMAINING OUT OF THE WEST...AND WELL WITHIN THE 30 DEGREE TOLERANCE
FOR LES. IT APPEARS AS IF THE TIME FRAME FOR HEAVIER LES WOULD OCCUR
THURSDAY EVENING INTO FRIDAY MORNING AS INVERSION HEIGHTS INCREASE
TO AROUND 8-9KFT AFTER ADJUSTING FOR LAKE SURFACE TEMPERATURES. THE
MOISTURE IS COLLOCATED WITH THE DGZ WHICH WOULD BE MORE FAVORABLE
FOR SNOWFLAKE PRODUCTION. FRIDAY AFTERNOON THROUGH SATURDAY
INVERSION HEIGHTS ARE EXPECTED TO BECOME MORE SHALLOW AS
TEMPERATURES ALSO BEGIN TO RAPIDLY DROP AS THE NEXT TROUGH AXIS
PRESSES INTO THE AREA. THESE COLDER TEMPERATURES WILL PRESS THE DGZ
DOWN TO THE VERY LOWEST LEVELS OF THE ATMOSPHERE. WHILE IT IS LIKELY
THAT SNOW WILL CONTINUE TO FALL THROUGH THE FRIDAY AFTERNOON INTO
SATURDAY TIME PERIOD...SNOW PRODUCTION WILL BE LIMITED AS THE
MOISTURE IS MAINLY OUTSIDE OF THE DGZ. TEMPERATURES THIS WEEKEND
WILL BE WELL BELOW NORMAL WITH TEMPERATURES DROPPING INTO THE TEENS
BELOW ZERO FRIDAY NIGHT INTO SATURDAY NIGHT...ESPECIALLY OVER THE
WEST HALF. HIGH TEMPERATURES WILLS STRUGGLE TO GET OUT OF THE SINGLE
DIGITS OVER WESTERN AREAS. WIND CHILLS THIS WEEKEND WILL BECOME
DANGEROUSLY COLD WITH READINGS DROPPING TO AROUND 30 BELOW ZERO OVER
THE INTERIOR WEST.
SATURDAY NIGHT THROUGH MONDAY...A SURFACE HIGH PRESSURE SYSTEM IS
PROGGED TO MOVE INTO THE UPPER GREAT LAKES REGION AS UPPER LEVEL
FLOW BECOMES SLIGHTLY MORE ZONAL SATURDAY NIGHT THROUGH SUNDAY. THIS
ALONG WITH DRYER AIR WILL ALLOW LAKE EFFECT SNOT TO DIMINISH. LOW
PRESSURE WILL THEN BUILD BACK INTO THE AREA SUNDAY NIGHT INTO
MONDAY. WINDS WILL BECOME SOUTH TO SOUTHWESTERLY DURING THIS TIME
PERIOD WHILE TEMPERATURES ALOFT AT 850MB LINGER AROUND -15C WHICH
WILL HELP LES TO DEVELOP OVER THE FAR EASTERN UPPER PENINSULA AS THE
WIND FLOW WOULD BE DIRECTLY ACROSS THE WARM WATERS OF LAKE MICHIGAN.
THE BEST CHANCE OF THIS HAPPENING WOULD BE SUNDAY NIGHT INTO MONDAY
MORNING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1228 PM EST TUE DEC 3 2013
VERY CHALLENGING FORECAST THIS AFTERNOON AND TOMORROW AS APPROACHING
LOW PRESSURE WITH SEVERAL UPPER LEVEL SHORTWAVES ARE EXPECTED TO
MOVE THROUGH THE AREA. THE MAIN QUESTION IS PRECIPITATION TYPE...AND
HOW LOW VISIBILITIES/CEILINGS WILL DIP DOWN. GENERALLY LIGHT SNOW
SHOWERS OVER NORTHERN WI AND WESTERN LAKE SUPERIOR WILL CONTINUE TO
MOVE THROUGH IWD THROUGH THE AFTERNOON...BUT VISIBILITIES SHOULD NOT
DIP TOO LOW GIVEN THE DOWNSLOPE WIND DIRECTION. SAW AND CMX WILL
CONTINUE TO SEE FLUCTUATING VISIBILITIES THROUGH MID AFTERNOON
TODAY...UNTIL A BRIEF BREAK IN MORE INTENSE PRECIPITATION ARRIVES.
OVERALL...HAVE IFR TO MVFR CONDITIONS THROUGH THE TIME PERIOD.
FOR THE LOW PRESSURE SYSTEM MOVING IN TONIGHT AND
TOMORROW...DIFFERENCES AMONGST MODELS ARE LEADING TO A DIFFICULT
FORECAST FOR PRECIPITATION TYPE. CURRENT THINKING IS THAT ACROSS
WESTERN UPPER MICHIGAN...FOR CMX/IWD THE PTYPE WILL BE PRIMARILY
SNOW. IF WARMER AIR WITH THE SYSTEM CAN REACH FURTHER NORTH AND
WESTWARD...THESE SITES MAY SEE FREEZING RAIN/SNOW MIX...BUT DID NOT
FEEL CONFIDENT ENOUGH TO PLACE INTO THE TAF AT THIS TIME. FOR
SAW...HAVE INCLUDED -RASN FOR NOW...BUT -FZRA COULD OCCUR IN THE
AFTERNOON AS TEMPERATURES WARM.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 AM EST TUE DEC 3 2013
EXPECT INCREASING E WINDS THRU TONIGHT AS THE PRES GRADIENT TIGHTENS
OVER THE UPPER LAKES BETWEEN HI PRES OVER NORTHERN ONTARIO AND LO
PRES TAKING SHAPE IN THE PLAINS. THE STRONGEST WINDS WILL BE OVER
WESTERN LAKE SUPERIOR...WHERE THE TERRAIN SURROUNDING THE LAKE
FUNNELS AND ENHANCES THE LARGER SCALE WINDS. MAINTAINED GOING GALE
WARNINGS FOR THE TWO WESTERN ZONES AND MENTIONED SOME GALE FORCE
GUSTS OVER THE CENTRAL AS WELL THIS AFTERNOON THRU TONIGHT.
LOW PRESSURE WILL MOVE ACROSS THE UPPER GREAT LAKES LATE WED THROUGH
THU MORNING. IN THE WAKE OF THE LOW...VERY COLD AIR ADVECTING OVER
THE RELATIVELY WARM WATERS WILL INCREASE INSTABILITY AND RESULT IN W
TO NW GALES AT TIMES FOR PORTIONS OF LAKE SUPERIOR WED NIGHT/THU.
CONTINUED FLOW OF VERY COLD AIR MAY RESULT IN A FEW GALE FORCE GUSTS
INTO SATURDAY BEFORE HIGH PRESSURE BUILDS IN SUNDAY. THIS HIGH
PRESSURE SYSTEM WILL MOVE DIRECTLY OVERHEAD BY SUNDAY AFTERNOON
ALLOW WINDS TO BECOME LIGHT AND VARIABLE. BUILDING WAVES AND THE
ARRIVAL OF THE ARCTIC AIR WILL CAUSE AN INCREASING FREEZING SPRAY
POTENTIAL FOR THE LAST HALF OF THE WORK WEEK AND INTO THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 AM EST /9 AM CST/ WEDNESDAY FOR LSZ162.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST WEDNESDAY FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...KC
LONG TERM...KEC
AVIATION...MCD
MARINE...KC/KEC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1154 AM EST TUE DEC 3 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 341 AM EST TUE DEC 3 2013
A WARM FRONT MOVING THROUGH LOWER MICHIGAN WILL BRING LIGHT SNOW
POSSIBLY MIXED WITH SLEET AND FREEZING RAIN THIS MORNING. WE DON/T
EXPECT MUCH IF ANY ACCUMULATION. HOWEVER A FEW ROADS COULD BECOME
SLICK. THE PCPN WILL BECOME LIGHT RAIN THIS AFTERNOON AS WARMER AIR
MOVES INTO THE REGION.
A STRONG COLD FRONT WILL MOVE THROUGH WEDNESDAY NIGHT BRINGING AN
ABRUPT END TO THE 50 DEGREE TEMPERATURES EXPECTED WEDNESDAY. SNOW
SHOWERS AND HIGHS IN THE 20S ARE EXPECTED FRIDAY THROUGH THE
WEEKEND.
&&
.UPDATE...
ISSUED AT 1154 AM EST TUE DEC 3 2013
I UPDATED THE GRIDS TO KEEP THE CHANCE OF FREEZING RAIN GOING INTO
THE EVENING NEAR ROUTE 10...EAST OF US-131 (OVER THE HIGHER
TERRAIN AREAS). ALSO I INCREASED THE CHANCE OF RAIN OVER SOUTHERN
AREAS ANOTHER SHORTWAVE HEADS INTO THE AREA THIS AFTERNOON. THIS
IS SEEN NICELY ON BOTH THE WATER VAPOR AND IR IMAGE LOOPS FROM MN
TO WI INTO IL AT 11 AM. AS THAT MOVES NORTH AND EAST IT SHOULD
SHOULD KEEP THE RAIN GOING NORTH OF ROUTE 2O INTO THE LATE
EVENING HOURS BUT ALLOW THE RAIN SHOULD END FOR AWHILE OVER AREAS
NEAR AND SOUTH OF I-96.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
FORECAST CONCERNS DEAL WITH MIXED PCPN MAINLY THIS MORNING.
LATEST RADAR SHOWS A BAND OF PCPN STRETCHING FROM OCEANA COUNTY
SOUTHEAST TOWARD NW OHIO MOVING NEED THROUGH THE CWA. MOST OF THIS
IS LIGHT SHOW BUT LOCAL OBS HAVE SHOWN SOME SLEET TOO. THIS WAS
CORROBORATED BY DUAL POL. LATEST HRRR AND FCST SOUNDINGS SUGGEST
SOME
LIGHT FREEZING RAIN IS POSSIBLE TOO THIS MORNING BEFORE TEMPS WARM
UP ENOUGH TO RESULT IN LIGHT RAIN. PCPN IS FAIRLY LIGHT AND ANY
ACCUMS SHOULD REMAIN LESS THAN AN INCH. THAT SAID...A FEW ROADS MAY
BECOME SLICK.
A WARM FRONT WILL CONTINUE TO PUSH NORTH THROUGH THE CWA TONIGHT. H8
TEMPS RISING TO 7C SHOULD RESULT IN SFC TEMPS IN THE 50S TOMORROW.
MODELS CONTINUE TO BE AT ODDS ON COLD FRONTAL TIMING. WE/LL BE
CONSISTENT THOUGH IN FOLLOWING THE SLOWER ECMWF DUE TO THE OCCLUDING
NATURE OF THE SYSTEM. THAT MEANS A FROPA WEDNESDAY NIGHT. HIGHS
THURSDAY WILL BE IN THE MID 30S. LIGHT SNOW SHOWERS POSSIBLE
THURSDAY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
TWO MAIN HEADLINES OF THE LONG TERM REMAIN THE COLD AND LAKE EFFECT
SNOW SHOWERS. THE COLD MAY BE THE BIGGER STORY AS THE LAKE EFFECT
LOOKS TO BE SOMEWHAT MOISTURE DEPLETED.
COLD AIR ADVECTION WILL BE IN FULL SWING THURSDAY NIGHT AS WE BEGIN
THE LONG TERM WITH THE LOW MOVING AWAY ACROSS ONTARIO. DELTA T/S
WILL BE IN THE MIDDLE TEENS...PROVIDING DECENT INSTABILITY. MOISTURE
LOOKS LIMITED SO NOT EXPECTING ANYTHING IN THE WAY OF SIGNIFICANT
LAKE EFFECT. MINOR ACCUMULATIONS AT BEST.
THAT REALLY REMAINS THE CASE FOR FRIDAY THROUGH SATURDAY. CONTINUED
COLD AIR ADVECTION WILL PUSH DELTA T/S INTO THE LOWER 20S C...BUT
MOISTURE REMAINS A LIMITING FACTOR. WE NEVER DEEPLY PLUNGE INTO
CYCLONIC FLOW TO THE NORTH SIDE OF THE UPPER JET AXIS...INSTEAD
REMAINING IN A BROAD SOUTHWEST TO WEST FLOW. 1000-700MB RH VALUES
FROM FRIDAY THROUGH SATURDAY REMAIN IN THE 40-60 PCT RANGE WHICH IS
NOT IDEAL. 20-40 PCT CHANCES FOR SNOW SHOWERS THURSDAY NIGHT THROUGH
SATURDAY SEEM WARRANTED. AT THIS POINT NOT EXPECTING ANY BIG
ACCUMULATIONS...JUST PERSISTENT LIGHT SNOW SHOWERS.
LOW PRESSURE IS FORECAST BY THE ECMWF (STILL THE MODEL OF CHOICE
TONIGHT) TO SWING NORTH THROUGH THE AREA SUNDAY NIGHT INTO MONDAY
WHICH BRINGS A GENERAL LIGHT SYNOPTIC SNOW TO THE AREA.
LOWS IN THE TEENS THROUGH THE PERIOD WITH HIGHS IN THE 20S WILL BE
COMMON. THIS IS COLDER THAN NORMAL...BUT BY NO MEANS RARE FOR EARLY
DECEMBER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 711 AM EST TUE DEC 3 2013
AVIATION CONDITIONS SHOULD CONTINUE TO DETERIORATE THE NEXT 24
HOURS...WITH WIDESPREAD IFR EXPECTED THIS AFTERNOON. OVERNIGHT
MOST SITES SHOULD SEE CEILINGS DROP FURTHER...INTO LIFR.
A MIXTURE OF PRECIPITATION IS OCCURRING THIS MORNING AS WARMER AIR
SURGES INTO THE REGION ALOFT. SOME SNOW...SLEET AND FREEZING RAIN
MAY MIX IN FROM TIME TO TIME THROUGH 15Z OR SO. BY MIDDAY...ALL
PRECIPITATION SHOULD HAVE SWITCHED OVER TO RAIN. SCATTERED RAIN
SHOWERS WILL BE POSSIBLE THIS AFTERNOON AND EVENING.
CEILINGS SHOULD CONSISTENTLY LOWER THE NEXT 24 HOURS. FOG SHOULD
BECOME MORE PREVALENT WITH TIME...WITH IFR VISIBILITIES BECOMING
FAIRLY WIDESPREAD TONIGHT.
&&
.MARINE...
ISSUED AT 341 AM EST TUE DEC 3 2013
SOUTH TO SOUTHEAST WINDS WILL INCREASE TO 15 TO 25 KNOTS TODAY. THE
OFFSHORE NATURE OF THE WINDS SHOULD PRECLUDE WAVES FROM GETTING
HIGHER THAN 3 FEET.
&&
.HYDROLOGY...
ISSUED AT 341 AM EST TUE DEC 3 2013
NO HYDRO ISSUES TODAY. HOWEVER THE ARCTIC AIR EXPECTED BY THE END OF
THE WEEK COULD CAUSE ICE TO DEVELOP ON STREAMS AND RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
740 AM EST TUE DEC 3 2013
.UPDATE...
ISSUED AT 739 AM EST TUE DEC 3 2013
OPTED TO ADD SOME PATCHY -FZDZ TO THE FCST FOR LATER THIS MRNG/AFTN
FOR MUCH OF THE W HALF OF UPR MM WITH EXPECTATION THAT MID LVL
DRYING ASSOCIATED WITH DNVA/LARGER SCALE QVECTOR DVGC IN THE WAKE OF
DEPARTING SHRTWV WL DRY OUT THE DGZ LYR IN THE 10-12K FT RANGE. SFC
OBS IN NCENTRAL WI SHOW SOME OF THIS PCPN THERE...SO CONFIDENCE IS
INCREASED THIS WL HAPPEN AS WELL IN THE CWA WITH THE ONSET OF MID
LVL DRYING. EXCLUDED THIS PTYPE OVER THE FAR W WHERE LLVL E-SE FLOW
DOWNSLOPES/DRIES AND OVER THE E HALF WHERE LLVL DRY AIR HAS PROVEN
TO BE MORE RESILIENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 447 AM EST TUE DEC 3 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW RELATIVELY WEAK
ZONAL FLOW ALF OVER THE UPR GRT LKS TO THE N OF FASTER POLAR JET
OVER THE SRN 2/3 OF THE CONUS. THERE ARE 2 SHRTWVS OF NOTE EMBEDDED
IN THIS FLOW. THE FIRST IS MOVING E THRU MN AND CAUSING A BAND OF SN
EXTENDING FM NE MN SEWD OVER WRN LK SUP AND INTO CENTRAL WI AS OF
06Z UNDER AREA OF H85-5 QVECTOR CNVGC. THE AXIS OF HIER
REFLECTIVITIES IN WI APPEARS TO BE ORIENTED ALONG THE MOST
IMPRESSIVE ISENTROPIC ASCENT SHOWN ON THE 290K SFC /H7-75/...WHILE
THE MOST IMPRESSIVE RETURNS IN NE MN ALIGN WITH MOST VIGOROUS H85-5
QVECTOR CNVGC. THE 00Z INL/MPX RAOBS SHOW DEEP MSTR THRU THE DEPTH
OF THE TROP. ELY FEED OF DRIER LLVL AIR ASSOCIATED WITH AREA OF
MOCLR SKIES/HI PRES RDG AXIS STILL OVER FAR ERN UPR MI AND LOCATION
OF SHARPER H85 THERMAL PACKING/ISENTROPIC ASCENT TO THE S HAS SO FAR
LIMITED THE ENE EXTENT OF THE PCPN INTO UPR MI...BUT SN APPEARS
POISED TO SPREAD INTO THE WRN CWA PER LATEST SFC OBS/RADAR IMAGERY.
THE VSBY AT IWD FELL UNDER 2 MILES AT 07Z...AND THE VSBY AS CLOSE AS
ASHLAND IN NW WI IS DOWN TO 1/2 MILE. ENE FLOW DOWN WRN LK SUP MAY
BE ENHANCING THE SN INTO THIS AREA. IN THE AREA OVER WRN MN/MUCH OF
THE DAKOTAS UNDER DNVA/DEEP LYR QVECTOR DVGC BEHIND THE MN SHRTWV...
THERE IS LTL IF ANY PCPN FALLING EVEN THOUGH SKIES REMAIN CLDY WITH
QUITE A BIT OF MID LVL DRYING ABV LLVL MSTR SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. FARTHER TO THE W...THE 2ND MORE IMPRESSIVE
SHRTWV OF INTEREST IS MOVING EWD THRU THE NRN ROCKIES. 12HR H3 HGT
FALLS UP TO 200M AND H3 WIND SPEEDS UP TO 100M IN THE ACCOMPANYING
JET CORE ARE ASSOCIATED WITH THIS MORE IMPRESSIVE DISTURBANCE.
MAIN FCST CONCERNS IN THE SHORT TERM PERIOD ARE POPS/EXPECTED SN
ACCUMS THRU THIS MRNG ASSOCIATED WITH THE FIRST SHRTWV IN MN AND
NEED FOR ANY HEADLINES. FOCUS FOR TNGT TURNS TO POPS AND SN AMOUNTS
THAT WL ACCOMPANY THE APRCH OF THE 2ND STRONGER SHRTWV.
TODAY...AS MN SHRTWV TRACKS TO THE E INTO PERSISTENT SFC RDG AXIS
JUST TO THE E OF UPR MI AND AWAY FM TROF DEEPENING OVER THE W...
AREA OF H85-5 QVECTOR CNVGC IS PROGGED TO DIMINISH SGNFTLY BY 18Z
WITH MID LVL DRYING UNDER DVLPG H85-5 QVECTOR DVGC. EXPECT THE HIER
POPS THIS MRNG OVER THE W AND SCENTRAL UNDER THE SHARPER H85-5
QVECTOR CVNGC/SHARPER 295K ISENTROPIC ASCENT/AREA OF H85-7 FGEN.
GIVEN PRESENCE OF 2.5G/KG SPECIFIC HUMIDITY AT THIS LVL...EXPECT UP
TO 3 INCHES OF SN FOR THE 6-9 HR PERIOD OVER THE SW HALF OF THE CWA.
SINCE THE SN IS LIKELY TO FALL A FOR CLOSER TO 12Z HRS AT IWD...UP
TO 4 INCHES MAY ACCUMULATE THERE BEFORE THE PCPN DIMINISHES TOWARD
NOON. ALTHOUGH THE DGZ IS RATHER NARROW...MODELS SHOW FAIRLY
IMPRESSIVE OMEGA IN THIS LYR THAT MAY INCH SN/WATER RATIOS CLOSER
TO 15:1. CONSIDERING THE LO VSBYS REPORTED AT ASHLAND IN THE ABSENCE
OF LAKE ENHANCEMENT WITH THE LARGER SCALE E WIND...OPTED TO ISSUE A
WINTER WX ADVY FOR GOGEBIC COUNTY THRU MID MRNG. OTRW...UPSLOPE E
WIND OFF LK MI MAY CAUSE STEADIER SN TO LINGER LONGER OVER THE
SCENTRAL. SN WL LIKELY MOVE INTO THE E DURING THE AFTN BUT WL BE MUCH
LIGHTER AS THE DYNAMIC SUPPORT FADES AND HITS DRIER AIR.
TNGT...ALTHOUGH THE EARLY EVNG WL FEATURE DNVA/LARGER SCALE QVECTOR
DVGC LEFT IN THE WAKE OF THE DEPARTING/WEAKENING SHRTWV...FAVORED
CNDN MODEL SHOWS AXIS OF SHARPER H85-7 FGEN SUPPORTING BAND OF SN
NOW OVER SDAKOTA IMPACTING MAINLY THE SRN CWA FOR A COUPLE HRS IN
THE LATER EVNG. THE 00Z GFS/ECWMF SHOW A SIMILAR QPF...SO WENT FOR
HI END LIKELY POPS IN THIS AREA BY LATER IN THE EVNG. OVERALL MODEL
QPF UP TO 0.25 INCH WL SUPPORT A FEW INCHES OF SN IN THIS AREA. HIER
POPS/MORE SN MAY ARRIVE LATE OVER THE W AS THE DYNAMICS IN ADVANCE
OF THE SHRTWV MOVING THRU THE NRN ROCKIES PUSH TOWARD THE AREA. BUT
MODELS DISAGREE ON THE TIMING OF THE ARRIVAL OF THE DEEP LYR QVECTOR
CNVGC AS WELL AS INTENSITY OF THE SFC LO THAT MIGHT ACCOMPANY THE
LARGER SCALE FORCING. THE NAM/LOCAL WRF-ARW MODELS ARE THE MOST
AGGRESSIVE AT DEEPENING THE SFC LO AND BRINGING MORE PCPN FARTHER E.
BUT SINCE THE MAIN SHRTWV REMAINS SO FAR TO THE W THRU THE NGT...
SUSPECT THE SLOWER/WEAKER CNDN MODEL IS ON THE RIGHT TRACK. SO WENT
NO HIER THAN LIKELY POPS OVER THE FAR W FOR NOW. THE THERMAL FIELDS
FM THE CNDN MODEL INDICATE ENUF WARM AIR WL ARRIVE TO CAUSE THE SN
TO MIX WITH RA OVER THE FAR SCENTRAL.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 447 AM EST TUE DEC 3 2013
CONTINUED CHALLENGING FORECAST IN STORE FOR WEDNESDAY THROUGH
WEDNESDAY NIGHT TIME FRAME AS A WINTER WEATHER SYSTEM TAKES AIM AT
THE UPPER GREAT LAKES. VERY COLD AIR IS EXPECTED TO BUILD IN ON THE
BACK SIDE OF THIS SYSTEM ALLOWING FOR VERY COLD TEMPERATURES FRIDAY
NIGHT THROUGH SATURDAY NIGHT.
WEDNESDAY INTO WEDNESDAY NIGHT...SITUATION LOOKS A BIT BETTER FROM A
FORECASTING STANDPOINT AS MODELS ARE COMING INTO BETTER AGREEMENT
WITH RESPECT TO THE HANDLING OF THE LOW PRESSURE SYSTEM POISED TO
AFFECT THE AREA THROUGH THIS TIME PERIOD. THE 00Z RUN OF THE NAM AND
GFS ARE FINALLY ALIGNING BETTER WITH THE MORE CONSISTENT
EC/GEM...ALTHOUGH THEY ARE A TOUCH FASTER AT SHIFTING THE LOW INTO
THE UPPER PENINSULA. AS OF 12Z/04 EACH OF THE MODELS ARE IN GOOD
AGREEMENT IN PLACING THE SURFACE LOW OVER SW WISCONSIN WITH VERY
SIMILAR INTENSITIES. THE UPPER LEVEL 500MB CLOSED LOW IS PROGGED TO
BE POSITIONED FARTHER NORTHWEST OVER NORTHWESTERN MN...INDICATING
THE POTENTIAL FOR ADDITIONAL INTENSIFICATION OF THE SURFACE LOW. AT
THAT TIME ISENTROPIC UPGLIDE IS EXPECTED TO CONTINUE AS SHOWN BY
ANALYZING MOISTURE AND MOISTURE TRANSPORT ON A 295K PRESSURE
ISOSURFACE. SOUNDINGS AROUND 12Z/04 INDICATE THAT MOST OF THE
PRECIPITATION EAST OF A MQT TO IMT LINE WILL LIKELY BE IN THE FORM
OF RAIN AS A FAIRLY DEEP WARM LAYER EXISTS IN THE BOUNDARY LAYER.
WEST OF THAT LINE ATMOSPHERIC PROFILES ARE SUCH THAT THE
PRECIPITATION SHOULD REMAIN IN THE FORM OF SNOW. ALSO AT THIS TIME
FORCING IN THE DGZ SEEMS FAIRLY LIMITED...HOWEVER...THIS WILL CHANGE
THROUGH THE DAY. THE LOW IS PROGGED TO BE OVER SOUTH CENTRAL WI BY
18Z/04. AS THIS LOW CONTINUES TO APPROACH DURING THIS TIME PERIOD
INCREASED MOISTURE AND FORCING IN THE DGZ IS EXPECTED TO INCREASE
ALLOWING FOR A STEADY INCREASE IN SNOWFALL INTENSITY DURING THE
AFTERNOON HOURS. BETWEEN 00Z/05 AND 06Z/05 THE LOW IS PROGGED TO
SHIFT NORTH AND EASTWARD INTO THE EAST CENTRAL PORTION OF THE UPPER
PENINSULA. INCREASED SNOWFALL RATES ARE EXPECTED TO CONTINUE DURING
THAT TIME PERIOD AS WELL...AS CONTINUED MOISTURE AND LIFT ARE
PROGGED TO BE COLLOCATED IN THE DGZ AS SHOWN BY ANALYZING 1000-500MB
RH AS WELL AS QCONV IN THE 700-500 DGZ LAYER AS IDENTIFIED USING
ATMOSPHERIC PROFILES OF THE EC/GEM. THE WESTERN HALF OF THE UPPER
PENINSULA LOOKS TO ALSO BE IN A FAVORED LOCATION FOR HEAVY SNOWFALL
AS THIS REGION IS IN THE FAVORED LEFT EXIT REGION OF AN UPPER LEVEL
JET. THE MAIN CAVEAT HERE IS THE NEW UNCERTAINTY WITH PRECIPITATION
TYPE WHICH WAS INTRODUCED BY THE 00Z EC/GEM/UKMET WHICH PULLS THE
SURFACE LOW MUCH FARTHER TO THE WEST...WHICH TAKES THE LOW VERY NEAR
WHERE THE PREVIOUS GFS MODELS WERE TAKING IT OVER THE PAST COUPLE OF
DAYS. THIS WOULD SHIFT THE RAIN SNOW LINE FARTHER WEST...POSSIBLY
REDUCING SNOWFALL TOTALS. HAVE DECIDED TO CONTINUE WITH AN UPDATED
SPS BASED ON COORDINATION WITH SURROUNDING OFFICES...AS CONFIDENCE
IS NOT HIGH ENOUGH AT THIS POINT TO GO WITH A HEADLINE.
THURSDAY THROUGH SATURDAY...BETWEEN 12Z/05 AND 18Z/05 THE SURFACE
LOW IS PROGGED TO SHIFT NORTHEASTWARD TO JUST SOUTH OF JAMES
BAY...TAKEN THE BETTER SYNOPTIC FORCING OUT OF THE AREA. AT THE SAME
TIME A DEEP TROUGH DIGGING INTO THE NORTHERN PLAINS WILL BEGIN TO
INFLUENCE THE WEATHER IN THE UPPER PENINSULA. WINDS WILL BECOME
WESTERLY TO WEST NORTHWESTERLY IN THE RETURN FLOW ON THE BACK SIDE
OF THE LOW PRESSURE SYSTEM. THIS WILL ALLOW LAKE EFFECT SNOW DEVELOP
IN THE SNOWBELTS FAVORED WITH THE SAID WIND DIRECTION. 850MB
TEMPERATURES ARE EXPECTED TO DROP FROM NEAR -14C 12/05 TO AROUND
-22C 12Z/07. THESE TEMPERATURES ARE MORE THAN FAVORABLE FOR LES
GIVEN LAKE SURFACE TEMPERATURES AROUND 4C TO 5C...CREATING DELTA T
VALUES BETWEEN 18 AND 27 DEGREES THROUGH THIS TIME PERIOD.
WINDS...AGAIN...LOOK TO BE FAVORABLE WITH SURFACE TO 850MB WINDS
REMAINING OUT OF THE WEST...AND WELL WITHIN THE 30 DEGREE TOLERANCE
FOR LES. IT APPEARS AS IF THE TIME FRAME FOR HEAVIER LES WOULD OCCUR
THURSDAY EVENING INTO FRIDAY MORNING AS INVERSION HEIGHTS INCREASE
TO AROUND 8-9KFT AFTER ADJUSTING FOR LAKE SURFACE TEMPERATURES. THE
MOISTURE IS COLLOCATED WITH THE DGZ WHICH WOULD BE MORE FAVORABLE
FOR SNOWFLAKE PRODUCTION. FRIDAY AFTERNOON THROUGH SATURDAY
INVERSION HEIGHTS ARE EXPECTED TO BECOME MORE SHALLOW AS
TEMPERATURES ALSO BEGIN TO RAPIDLY DROP AS THE NEXT TROUGH AXIS
PRESSES INTO THE AREA. THESE COLDER TEMPERATURES WILL PRESS THE DGZ
DOWN TO THE VERY LOWEST LEVELS OF THE ATMOSPHERE. WHILE IT IS LIKELY
THAT SNOW WILL CONTINUE TO FALL THROUGH THE FRIDAY AFTERNOON INTO
SATURDAY TIME PERIOD...SNOW PRODUCTION WILL BE LIMITED AS THE
MOISTURE IS MAINLY OUTSIDE OF THE DGZ. TEMPERATURES THIS WEEKEND
WILL BE WELL BELOW NORMAL WITH TEMPERATURES DROPPING INTO THE TEENS
BELOW ZERO FRIDAY NIGHT INTO SATURDAY NIGHT...ESPECIALLY OVER THE
WEST HALF. HIGH TEMPERATURES WILLS STRUGGLE TO GET OUT OF THE SINGLE
DIGITS OVER WESTERN AREAS. WIND CHILLS THIS WEEKEND WILL BECOME
DANGEROUSLY COLD WITH READINGS DROPPING TO AROUND 30 BELOW ZERO OVER
THE INTERIOR WEST.
SATURDAY NIGHT THROUGH MONDAY...A SURFACE HIGH PRESSURE SYSTEM IS
PROGGED TO MOVE INTO THE UPPER GREAT LAKES REGION AS UPPER LEVEL
FLOW BECOMES SLIGHTLY MORE ZONAL SATURDAY NIGHT THROUGH SUNDAY. THIS
ALONG WITH DRYER AIR WILL ALLOW LAKE EFFECT SNOT TO DIMINISH. LOW
PRESSURE WILL THEN BUILD BACK INTO THE AREA SUNDAY NIGHT INTO
MONDAY. WINDS WILL BECOME SOUTH TO SOUTHWESTERLY DURING THIS TIME
PERIOD WHILE TEMPERATURES ALOFT AT 850MB LINGER AROUND -15C WHICH
WILL HELP LES TO DEVELOP OVER THE FAR EASTERN UPPER PENINSULA AS THE
WIND FLOW WOULD BE DIRECTLY ACROSS THE WARM WATERS OF LAKE MICHIGAN.
THE BEST CHANCE OF THIS HAPPENING WOULD BE SUNDAY NIGHT INTO MONDAY
MORNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 641 AM EST TUE DEC 3 2013
IWD...WITH A DOWNSLOPE E WIND AND WEAKENING BAND OF -SN...EXPECT
CONDITIONS TO IMPROVE TO VFR THIS MRNG AND AFTN. ANOTHER DISTURBANCE
APRCHG FM THE W TNGT MAY BRING A PERIOD OF SOME STEADIER -SN AND
MVFR TO PERHAPS IFR CONDITIONS.
CMX...EXPECT PREDOMINANT MVFR CONDITIONS TO DOMINATE THIS FCST
PERIOD WITH GUSTY UPSLOPE E WIND. ALTHOUGH THIS FLOW COULD BRING IFR
CONDITIONS...DRY UPSTREAM LLVL AIRMASS WILL LIMIT HOW FAR THE CIG
WILL DROP.
SAW...AS WEAKENING BAND OF -SN MOVES INTO THE AREA...EXPECT MVFR
CONDITIONS TO DVLP THIS MRNG WITH UPSLOPE E WIND. DRY NATURE OF THE
UPSTREAM LLVL AIRMASS WL LIMIT THE POTENTIAL FOR IFR CONDITIONS WITH
THIS UPSLOPE FLOW EVEN IF ANOTHER DISTURBANCE BRUSHES THE AREA WITH
SOME HEAVIER SN LATE THIS EVNG.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 AM EST TUE DEC 3 2013
EXPECT INCREASING E WINDS THRU TONIGHT AS THE PRES GRADIENT TIGHTENS
OVER THE UPPER LAKES BETWEEN HI PRES OVER NORTHERN ONTARIO AND LO
PRES TAKING SHAPE IN THE PLAINS. THE STRONGEST WINDS WILL BE OVER
WESTERN LAKE SUPERIOR...WHERE THE TERRAIN SURROUNDING THE LAKE
FUNNELS AND ENHANCES THE LARGER SCALE WINDS. MAINTAINED GOING GALE
WARNINGS FOR THE TWO WESTERN ZONES AND MENTIONED SOME GALE FORCE
GUSTS OVER THE CENTRAL AS WELL THIS AFTERNOON THRU TONIGHT.
LOW PRESSURE WILL MOVE ACROSS THE UPPER GREAT LAKES LATE WED THROUGH
THU MORNING. IN THE WAKE OF THE LOW...VERY COLD AIR ADVECTING OVER
THE RELATIVELY WARM WATERS WILL INCREASE INSTABILITY AND RESULT IN W
TO NW GALES AT TIMES FOR PORTIONS OF LAKE SUPERIOR WED NIGHT/THU.
CONTINUED FLOW OF VERY COLD AIR MAY RESULT IN A FEW GALE FORCE GUSTS
INTO SATURDAY BEFORE HIGH PRESSURE BUILDS IN SUNDAY. THIS HIGH
PRESSURE SYSTEM WILL MOVE DIRECTLY OVERHEAD BY SUNDAY AFTERNOON
ALLOW WINDS TO BECOME LIGHT AND VARIABLE. BUILDING WAVES AND THE
ARRIVAL OF THE ARCTIC AIR WILL CAUSE AN INCREASING FREEZING SPRAY
POTENTIAL FOR THE LAST HALF OF THE WORK WEEK AND INTO THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 11 AM CST THIS MORNING FOR MIZ009.
LAKE SUPERIOR...
GALE WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 10 AM
EST /9 AM CST/ WEDNESDAY FOR LSZ162.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST WEDNESDAY FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...KC
LONG TERM...KEC
AVIATION...KC
MARINE...KC/KEC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
711 AM EST TUE DEC 3 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 341 AM EST TUE DEC 3 2013
A WARM FRONT MOVING THROUGH LOWER MICHIGAN WILL BRING LIGHT SNOW
POSSIBLY MIXED WITH SLEET AND FREEZING RAIN THIS MORNING. WE DON/T
EXPECT MUCH IF ANY ACCUMULATION. HOWEVER A FEW ROADS COULD BECOME
SLICK. THE PCPN WILL BECOME LIGHT RAIN THIS AFTERNOON AS WARMER AIR
MOVES INTO THE REGION.
A STRONG COLD FRONT WILL MOVE THROUGH WEDNESDAY NIGHT BRINGING AN
ABRUPT END TO THE 50 DEGREE TEMPERATURES EXPECTED WEDNESDAY. SNOW
SHOWERS AND HIGHS IN THE 20S ARE EXPECTED FRIDAY THROUGH THE
WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
FORECAST CONCERNS DEAL WITH MIXED PCPN MAINLY THIS MORNING.
LATEST RADAR SHOWS A BAND OF PCPN STRETCHING FROM OCEANA COUNTY
SOUTHEAST TOWARD NW OHIO MOVING NEWD THROUGH THE CWA. MOST OF THIS
IS LIGHT SHOW BUT LOCAL OBS HAVE SHOWN SOME SLEET TOO. THIS WAS
CORROBORATED BY DUAL POL. LATEST HRRR AND FCST SOUNDINGS SUGGEST
SOME
LIGHT FREEZING RAIN IS POSSIBLE TOO THIS MORNING BEFORE TEMPS WARM
UP ENOUGH TO RESULT IN LIGHT RAIN. PCPN IS FAIRLY LIGHT AND ANY
ACCUMS SHOULD REMAIN LESS THAN AN INCH. THAT SAID...A FEW ROADS MAY
BECOME SLICK.
A WARM FRONT WILL CONTINUE TO PUSH NORTH THROUGH THE CWA TONIGHT. H8
TEMPS RISING TO 7C SHOULD RESULT IN SFC TEMPS IN THE 50S TOMORROW.
MODELS CONTINUE TO BE AT ODDS ON COLD FRONTAL TIMING. WE/LL BE
CONSISTENT THOUGH IN FOLLOWING THE SLOWER ECMWF DUE TO THE OCCLUDING
NATURE OF THE SYSTEM. THAT MEANS A FROPA WEDNESDAY NIGHT. HIGHS
THURSDAY WILL BE IN THE MID 30S. LIGHT SNOW SHOWERS POSSIBLE
THURSDAY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
TWO MAIN HEADLINES OF THE LONG TERM REMAIN THE COLD AND LAKE EFFECT
SNOW SHOWERS. THE COLD MAY BE THE BIGGER STORY AS THE LAKE EFFECT
LOOKS TO BE SOMEWHAT MOISTURE DEPLETED.
COLD AIR ADVECTION WILL BE IN FULL SWING THURSDAY NIGHT AS WE BEGIN
THE LONG TERM WITH THE LOW MOVING AWAY ACROSS ONTARIO. DELTA T/S
WILL BE IN THE MIDDLE TEENS...PROVIDING DECENT INSTABILITY. MOISTURE
LOOKS LIMITED SO NOT EXPECTING ANYTHING IN THE WAY OF SIGNIFICANT
LAKE EFFECT. MINOR ACCUMULATIONS AT BEST.
THAT REALLY REMAINS THE CASE FOR FRIDAY THROUGH SATURDAY. CONTINUED
COLD AIR ADVECTION WILL PUSH DELTA T/S INTO THE LOWER 20S C...BUT
MOISTURE REMAINS A LIMITING FACTOR. WE NEVER DEEPLY PLUNGE INTO
CYCLONIC FLOW TO THE NORTH SIDE OF THE UPPER JET AXIS...INSTEAD
REMAINING IN A BROAD SOUTHWEST TO WEST FLOW. 1000-700MB RH VALUES
FROM FRIDAY THROUGH SATURDAY REMAIN IN THE 40-60 PCT RANGE WHICH IS
NOT IDEAL. 20-40 PCT CHANCES FOR SNOW SHOWERS THURSDAY NIGHT THROUGH
SATURDAY SEEM WARRANTED. AT THIS POINT NOT EXPECTING ANY BIG
ACCUMULATIONS...JUST PERSISTENT LIGHT SNOW SHOWERS.
LOW PRESSURE IS FORECAST BY THE ECMWF (STILL THE MODEL OF CHOICE
TONIGHT) TO SWING NORTH THROUGH THE AREA SUNDAY NIGHT INTO MONDAY
WHICH BRINGS A GENERAL LIGHT SYNOPTIC SNOW TO THE AREA.
LOWS IN THE TEENS THROUGH THE PERIOD WITH HIGHS IN THE 20S WILL BE
COMMON. THIS IS COLDER THAN NORMAL...BUT BY NO MEANS RARE FOR EARLY
DECEMBER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 711 AM EST TUE DEC 3 2013
AVIATION CONDITIONS SHOULD CONTINUE TO DETERIORATE THE NEXT 24
HOURS...WITH WIDESPREAD IFR EXPECTED THIS AFTERNOON. OVERNIGHT
MOST SITES SHOULD SEE CEILINGS DROP FURTHER...INTO LIFR.
A MIXTURE OF PRECIPITATION IS OCCURRING THIS MORNING AS WARMER AIR
SURGES INTO THE REGION ALOFT. SOME SNOW...SLEET AND FREEZING RAIN
MAY MIX IN FROM TIME TO TIME THROUGH 15Z OR SO. BY MIDDAY...ALL
PRECIPITATION SHOULD HAVE SWITCHED OVER TO RAIN. SCATTERED RAIN
SHOWERS WILL BE POSSIBLE THIS AFTERNOON AND EVENING.
CEILINGS SHOULD CONSISTENTLY LOWER THE NEXT 24 HOURS. FOG SHOULD
BECOME MORE PREVALENT WITH TIME...WITH IFR VISIBILITIES BECOMING
FAIRLY WIDESPREAD TONIGHT.
&&
.MARINE...
ISSUED AT 341 AM EST TUE DEC 3 2013
SOUTH TO SOUTHEAST WINDS WILL INCREASE TO 15 TO 25 KNOTS TODAY. THE
OFFSHORE NATURE OF THE WINDS SHOULD PRECLUDE WAVES FROM GETTING
HIGHER THAN 3 FEET.
&&
.HYDROLOGY...
ISSUED AT 341 AM EST TUE DEC 3 2013
NO HYDRO ISSUES TODAY. HOWEVER THE ARCTIC AIR EXPECTED BY THE END OF
THE WEEK COULD CAUSE ICE TO DEVELOP ON STREAMS AND RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
642 AM EST TUE DEC 3 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 447 AM EST TUE DEC 3 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW RELATIVELY WEAK
ZONAL FLOW ALF OVER THE UPR GRT LKS TO THE N OF FASTER POLAR JET
OVER THE SRN 2/3 OF THE CONUS. THERE ARE 2 SHRTWVS OF NOTE EMBEDDED
IN THIS FLOW. THE FIRST IS MOVING E THRU MN AND CAUSING A BAND OF SN
EXTENDING FM NE MN SEWD OVER WRN LK SUP AND INTO CENTRAL WI AS OF
06Z UNDER AREA OF H85-5 QVECTOR CNVGC. THE AXIS OF HIER
REFLECTIVITIES IN WI APPEARS TO BE ORIENTED ALONG THE MOST
IMPRESSIVE ISENTROPIC ASCENT SHOWN ON THE 290K SFC /H7-75/...WHILE
THE MOST IMPRESSIVE RETURNS IN NE MN ALIGN WITH MOST VIGOROUS H85-5
QVECTOR CNVGC. THE 00Z INL/MPX RAOBS SHOW DEEP MSTR THRU THE DEPTH
OF THE TROP. ELY FEED OF DRIER LLVL AIR ASSOCIATED WITH AREA OF
MOCLR SKIES/HI PRES RDG AXIS STILL OVER FAR ERN UPR MI AND LOCATION
OF SHARPER H85 THERMAL PACKING/ISENTROPIC ASCENT TO THE S HAS SO FAR
LIMITED THE ENE EXTENT OF THE PCPN INTO UPR MI...BUT SN APPEARS
POISED TO SPREAD INTO THE WRN CWA PER LATEST SFC OBS/RADAR IMAGERY.
THE VSBY AT IWD FELL UNDER 2 MILES AT 07Z...AND THE VSBY AS CLOSE AS
ASHLAND IN NW WI IS DOWN TO 1/2 MILE. ENE FLOW DOWN WRN LK SUP MAY
BE ENHANCING THE SN INTO THIS AREA. IN THE AREA OVER WRN MN/MUCH OF
THE DAKOTAS UNDER DNVA/DEEP LYR QVECTOR DVGC BEHIND THE MN SHRTWV...
THERE IS LTL IF ANY PCPN FALLING EVEN THOUGH SKIES REMAIN CLDY WITH
QUITE A BIT OF MID LVL DRYING ABV LLVL MSTR SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. FARTHER TO THE W...THE 2ND MORE IMPRESSIVE
SHRTWV OF INTEREST IS MOVING EWD THRU THE NRN ROCKIES. 12HR H3 HGT
FALLS UP TO 200M AND H3 WIND SPEEDS UP TO 100M IN THE ACCOMPANYING
JET CORE ARE ASSOCIATED WITH THIS MORE IMPRESSIVE DISTURBANCE.
MAIN FCST CONCERNS IN THE SHORT TERM PERIOD ARE POPS/EXPECTED SN
ACCUMS THRU THIS MRNG ASSOCIATED WITH THE FIRST SHRTWV IN MN AND
NEED FOR ANY HEADLINES. FOCUS FOR TNGT TURNS TO POPS AND SN AMOUNTS
THAT WL ACCOMPANY THE APRCH OF THE 2ND STRONGER SHRTWV.
TODAY...AS MN SHRTWV TRACKS TO THE E INTO PERSISTENT SFC RDG AXIS
JUST TO THE E OF UPR MI AND AWAY FM TROF DEEPENING OVER THE W...
AREA OF H85-5 QVECTOR CNVGC IS PROGGED TO DIMINISH SGNFTLY BY 18Z
WITH MID LVL DRYING UNDER DVLPG H85-5 QVECTOR DVGC. EXPECT THE HIER
POPS THIS MRNG OVER THE W AND SCENTRAL UNDER THE SHARPER H85-5
QVECTOR CVNGC/SHARPER 295K ISENTROPIC ASCENT/AREA OF H85-7 FGEN.
GIVEN PRESENCE OF 2.5G/KG SPECIFIC HUMIDITY AT THIS LVL...EXPECT UP
TO 3 INCHES OF SN FOR THE 6-9 HR PERIOD OVER THE SW HALF OF THE CWA.
SINCE THE SN IS LIKELY TO FALL A FOR CLOSER TO 12Z HRS AT IWD...UP
TO 4 INCHES MAY ACCUMULATE THERE BEFORE THE PCPN DIMINISHES TOWARD
NOON. ALTHOUGH THE DGZ IS RATHER NARROW...MODELS SHOW FAIRLY
IMPRESSIVE OMEGA IN THIS LYR THAT MAY INCH SN/WATER RATIOS CLOSER
TO 15:1. CONSIDERING THE LO VSBYS REPORTED AT ASHLAND IN THE ABSENCE
OF LAKE ENHANCEMENT WITH THE LARGER SCALE E WIND...OPTED TO ISSUE A
WINTER WX ADVY FOR GOGEBIC COUNTY THRU MID MRNG. OTRW...UPSLOPE E
WIND OFF LK MI MAY CAUSE STEADIER SN TO LINGER LONGER OVER THE
SCENTRAL. SN WL LIKELY MOVE INTO THE E DURING THE AFTN BUT WL BE MUCH
LIGHTER AS THE DYNAMIC SUPPORT FADES AND HITS DRIER AIR.
TNGT...ALTHOUGH THE EARLY EVNG WL FEATURE DNVA/LARGER SCALE QVECTOR
DVGC LEFT IN THE WAKE OF THE DEPARTING/WEAKENING SHRTWV...FAVORED
CNDN MODEL SHOWS AXIS OF SHARPER H85-7 FGEN SUPPORTING BAND OF SN
NOW OVER SDAKOTA IMPACTING MAINLY THE SRN CWA FOR A COUPLE HRS IN
THE LATER EVNG. THE 00Z GFS/ECWMF SHOW A SIMILAR QPF...SO WENT FOR
HI END LIKELY POPS IN THIS AREA BY LATER IN THE EVNG. OVERALL MODEL
QPF UP TO 0.25 INCH WL SUPPORT A FEW INCHES OF SN IN THIS AREA. HIER
POPS/MORE SN MAY ARRIVE LATE OVER THE W AS THE DYNAMICS IN ADVANCE
OF THE SHRTWV MOVING THRU THE NRN ROCKIES PUSH TOWARD THE AREA. BUT
MODELS DISAGREE ON THE TIMING OF THE ARRIVAL OF THE DEEP LYR QVECTOR
CNVGC AS WELL AS INTENSITY OF THE SFC LO THAT MIGHT ACCOMPANY THE
LARGER SCALE FORCING. THE NAM/LOCAL WRF-ARW MODELS ARE THE MOST
AGGRESSIVE AT DEEPENING THE SFC LO AND BRINGING MORE PCPN FARTHER E.
BUT SINCE THE MAIN SHRTWV REMAINS SO FAR TO THE W THRU THE NGT...
SUSPECT THE SLOWER/WEAKER CNDN MODEL IS ON THE RIGHT TRACK. SO WENT
NO HIER THAN LIKELY POPS OVER THE FAR W FOR NOW. THE THERMAL FIELDS
FM THE CNDN MODEL INDICATE ENUF WARM AIR WL ARRIVE TO CAUSE THE SN
TO MIX WITH RA OVER THE FAR SCENTRAL.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 447 AM EST TUE DEC 3 2013
CONTINUED CHALLENGING FORECAST IN STORE FOR WEDNESDAY THROUGH
WEDNESDAY NIGHT TIME FRAME AS A WINTER WEATHER SYSTEM TAKES AIM AT
THE UPPER GREAT LAKES. VERY COLD AIR IS EXPECTED TO BUILD IN ON THE
BACK SIDE OF THIS SYSTEM ALLOWING FOR VERY COLD TEMPERATURES FRIDAY
NIGHT THROUGH SATURDAY NIGHT.
WEDNESDAY INTO WEDNESDAY NIGHT...SITUATION LOOKS A BIT BETTER FROM A
FORECASTING STANDPOINT AS MODELS ARE COMING INTO BETTER AGREEMENT
WITH RESPECT TO THE HANDLING OF THE LOW PRESSURE SYSTEM POISED TO
AFFECT THE AREA THROUGH THIS TIME PERIOD. THE 00Z RUN OF THE NAM AND
GFS ARE FINALLY ALIGNING BETTER WITH THE MORE CONSISTENT
EC/GEM...ALTHOUGH THEY ARE A TOUCH FASTER AT SHIFTING THE LOW INTO
THE UPPER PENINSULA. AS OF 12Z/04 EACH OF THE MODELS ARE IN GOOD
AGREEMENT IN PLACING THE SURFACE LOW OVER SW WISCONSIN WITH VERY
SIMILAR INTENSITIES. THE UPPER LEVEL 500MB CLOSED LOW IS PROGGED TO
BE POSITIONED FARTHER NORTHWEST OVER NORTHWESTERN MN...INDICATING
THE POTENTIAL FOR ADDITIONAL INTENSIFICATION OF THE SURFACE LOW. AT
THAT TIME ISENTROPIC UPGLIDE IS EXPECTED TO CONTINUE AS SHOWN BY
ANALYZING MOISTURE AND MOISTURE TRANSPORT ON A 295K PRESSURE
ISOSURFACE. SOUNDINGS AROUND 12Z/04 INDICATE THAT MOST OF THE
PRECIPITATION EAST OF A MQT TO IMT LINE WILL LIKELY BE IN THE FORM
OF RAIN AS A FAIRLY DEEP WARM LAYER EXISTS IN THE BOUNDARY LAYER.
WEST OF THAT LINE ATMOSPHERIC PROFILES ARE SUCH THAT THE
PRECIPITATION SHOULD REMAIN IN THE FORM OF SNOW. ALSO AT THIS TIME
FORCING IN THE DGZ SEEMS FAIRLY LIMITED...HOWEVER...THIS WILL CHANGE
THROUGH THE DAY. THE LOW IS PROGGED TO BE OVER SOUTH CENTRAL WI BY
18Z/04. AS THIS LOW CONTINUES TO APPROACH DURING THIS TIME PERIOD
INCREASED MOISTURE AND FORCING IN THE DGZ IS EXPECTED TO INCREASE
ALLOWING FOR A STEADY INCREASE IN SNOWFALL INTENSITY DURING THE
AFTERNOON HOURS. BETWEEN 00Z/05 AND 06Z/05 THE LOW IS PROGGED TO
SHIFT NORTH AND EASTWARD INTO THE EAST CENTRAL PORTION OF THE UPPER
PENINSULA. INCREASED SNOWFALL RATES ARE EXPECTED TO CONTINUE DURING
THAT TIME PERIOD AS WELL...AS CONTINUED MOISTURE AND LIFT ARE
PROGGED TO BE COLLOCATED IN THE DGZ AS SHOWN BY ANALYZING 1000-500MB
RH AS WELL AS QCONV IN THE 700-500 DGZ LAYER AS IDENTIFIED USING
ATMOSPHERIC PROFILES OF THE EC/GEM. THE WESTERN HALF OF THE UPPER
PENINSULA LOOKS TO ALSO BE IN A FAVORED LOCATION FOR HEAVY SNOWFALL
AS THIS REGION IS IN THE FAVORED LEFT EXIT REGION OF AN UPPER LEVEL
JET. THE MAIN CAVEAT HERE IS THE NEW UNCERTAINTY WITH PRECIPITATION
TYPE WHICH WAS INTRODUCED BY THE 00Z EC/GEM/UKMET WHICH PULLS THE
SURFACE LOW MUCH FARTHER TO THE WEST...WHICH TAKES THE LOW VERY NEAR
WHERE THE PREVIOUS GFS MODELS WERE TAKING IT OVER THE PAST COUPLE OF
DAYS. THIS WOULD SHIFT THE RAIN SNOW LINE FARTHER WEST...POSSIBLY
REDUCING SNOWFALL TOTALS. HAVE DECIDED TO CONTINUE WITH AN UPDATED
SPS BASED ON COORDINATION WITH SURROUNDING OFFICES...AS CONFIDENCE
IS NOT HIGH ENOUGH AT THIS POINT TO GO WITH A HEADLINE.
THURSDAY THROUGH SATURDAY...BETWEEN 12Z/05 AND 18Z/05 THE SURFACE
LOW IS PROGGED TO SHIFT NORTHEASTWARD TO JUST SOUTH OF JAMES
BAY...TAKEN THE BETTER SYNOPTIC FORCING OUT OF THE AREA. AT THE SAME
TIME A DEEP TROUGH DIGGING INTO THE NORTHERN PLAINS WILL BEGIN TO
INFLUENCE THE WEATHER IN THE UPPER PENINSULA. WINDS WILL BECOME
WESTERLY TO WEST NORTHWESTERLY IN THE RETURN FLOW ON THE BACK SIDE
OF THE LOW PRESSURE SYSTEM. THIS WILL ALLOW LAKE EFFECT SNOW DEVELOP
IN THE SNOWBELTS FAVORED WITH THE SAID WIND DIRECTION. 850MB
TEMPERATURES ARE EXPECTED TO DROP FROM NEAR -14C 12/05 TO AROUND
-22C 12Z/07. THESE TEMPERATURES ARE MORE THAN FAVORABLE FOR LES
GIVEN LAKE SURFACE TEMPERATURES AROUND 4C TO 5C...CREATING DELTA T
VALUES BETWEEN 18 AND 27 DEGREES THROUGH THIS TIME PERIOD.
WINDS...AGAIN...LOOK TO BE FAVORABLE WITH SURFACE TO 850MB WINDS
REMAINING OUT OF THE WEST...AND WELL WITHIN THE 30 DEGREE TOLERANCE
FOR LES. IT APPEARS AS IF THE TIME FRAME FOR HEAVIER LES WOULD OCCUR
THURSDAY EVENING INTO FRIDAY MORNING AS INVERSION HEIGHTS INCREASE
TO AROUND 8-9KFT AFTER ADJUSTING FOR LAKE SURFACE TEMPERATURES. THE
MOISTURE IS COLLOCATED WITH THE DGZ WHICH WOULD BE MORE FAVORABLE
FOR SNOWFLAKE PRODUCTION. FRIDAY AFTERNOON THROUGH SATURDAY
INVERSION HEIGHTS ARE EXPECTED TO BECOME MORE SHALLOW AS
TEMPERATURES ALSO BEGIN TO RAPIDLY DROP AS THE NEXT TROUGH AXIS
PRESSES INTO THE AREA. THESE COLDER TEMPERATURES WILL PRESS THE DGZ
DOWN TO THE VERY LOWEST LEVELS OF THE ATMOSPHERE. WHILE IT IS LIKELY
THAT SNOW WILL CONTINUE TO FALL THROUGH THE FRIDAY AFTERNOON INTO
SATURDAY TIME PERIOD...SNOW PRODUCTION WILL BE LIMITED AS THE
MOISTURE IS MAINLY OUTSIDE OF THE DGZ. TEMPERATURES THIS WEEKEND
WILL BE WELL BELOW NORMAL WITH TEMPERATURES DROPPING INTO THE TEENS
BELOW ZERO FRIDAY NIGHT INTO SATURDAY NIGHT...ESPECIALLY OVER THE
WEST HALF. HIGH TEMPERATURES WILLS STRUGGLE TO GET OUT OF THE SINGLE
DIGITS OVER WESTERN AREAS. WIND CHILLS THIS WEEKEND WILL BECOME
DANGEROUSLY COLD WITH READINGS DROPPING TO AROUND 30 BELOW ZERO OVER
THE INTERIOR WEST.
SATURDAY NIGHT THROUGH MONDAY...A SURFACE HIGH PRESSURE SYSTEM IS
PROGGED TO MOVE INTO THE UPPER GREAT LAKES REGION AS UPPER LEVEL
FLOW BECOMES SLIGHTLY MORE ZONAL SATURDAY NIGHT THROUGH SUNDAY. THIS
ALONG WITH DRYER AIR WILL ALLOW LAKE EFFECT SNOT TO DIMINISH. LOW
PRESSURE WILL THEN BUILD BACK INTO THE AREA SUNDAY NIGHT INTO
MONDAY. WINDS WILL BECOME SOUTH TO SOUTHWESTERLY DURING THIS TIME
PERIOD WHILE TEMPERATURES ALOFT AT 850MB LINGER AROUND -15C WHICH
WILL HELP LES TO DEVELOP OVER THE FAR EASTERN UPPER PENINSULA AS THE
WIND FLOW WOULD BE DIRECTLY ACROSS THE WARM WATERS OF LAKE MICHIGAN.
THE BEST CHANCE OF THIS HAPPENING WOULD BE SUNDAY NIGHT INTO MONDAY
MORNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 641 AM EST TUE DEC 3 2013
IWD...WITH A DOWNSLOPE E WIND AND WEAKENING BAND OF -SN...EXPECT
CONDITIONS TO IMPROVE TO VFR THIS MRNG AND AFTN. ANOTHER DISTURBANCE
APRCHG FM THE W TNGT MAY BRING A PERIOD OF SOME STEADIER -SN AND
MVFR TO PERHAPS IFR CONDITIONS.
CMX...EXPECT PREDOMINANT MVFR CONDITIONS TO DOMINATE THIS FCST
PERIOD WITH GUSTY UPSLOPE E WIND. ALTHOUGH THIS FLOW COULD BRING IFR
CONDITIONS...DRY UPSTREAM LLVL AIRMASS WILL LIMIT HOW FAR THE CIG
WILL DROP.
SAW...AS WEAKENING BAND OF -SN MOVES INTO THE AREA...EXPECT MVFR
CONDITIONS TO DVLP THIS MRNG WITH UPSLOPE E WIND. DRY NATURE OF THE
UPSTREAM LLVL AIRMASS WL LIMIT THE POTENTIAL FOR IFR CONDITIONS WITH
THIS UPSLOPE FLOW EVEN IF ANOTHER DISTURBANCE BRUSHES THE AREA WITH
SOME HEAVIER SN LATE THIS EVNG.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 AM EST TUE DEC 3 2013
EXPECT INCREASING E WINDS THRU TONIGHT AS THE PRES GRADIENT TIGHTENS
OVER THE UPPER LAKES BETWEEN HI PRES OVER NORTHERN ONTARIO AND LO
PRES TAKING SHAPE IN THE PLAINS. THE STRONGEST WINDS WILL BE OVER
WESTERN LAKE SUPERIOR...WHERE THE TERRAIN SURROUNDING THE LAKE
FUNNELS AND ENHANCES THE LARGER SCALE WINDS. MAINTAINED GOING GALE
WARNINGS FOR THE TWO WESTERN ZONES AND MENTIONED SOME GALE FORCE
GUSTS OVER THE CENTRAL AS WELL THIS AFTERNOON THRU TONIGHT.
LOW PRESSURE WILL MOVE ACROSS THE UPPER GREAT LAKES LATE WED THROUGH
THU MORNING. IN THE WAKE OF THE LOW...VERY COLD AIR ADVECTING OVER
THE RELATIVELY WARM WATERS WILL INCREASE INSTABILITY AND RESULT IN W
TO NW GALES AT TIMES FOR PORTIONS OF LAKE SUPERIOR WED NIGHT/THU.
CONTINUED FLOW OF VERY COLD AIR MAY RESULT IN A FEW GALE FORCE GUSTS
INTO SATURDAY BEFORE HIGH PRESSURE BUILDS IN SUNDAY. THIS HIGH
PRESSURE SYSTEM WILL MOVE DIRECTLY OVERHEAD BY SUNDAY AFTERNOON
ALLOW WINDS TO BECOME LIGHT AND VARIABLE. BUILDING WAVES AND THE
ARRIVAL OF THE ARCTIC AIR WILL CAUSE AN INCREASING FREEZING SPRAY
POTENTIAL FOR THE LAST HALF OF THE WORK WEEK AND INTO THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 11 AM CST THIS MORNING FOR MIZ009.
LAKE SUPERIOR...
GALE WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 10 AM
EST /9 AM CST/ WEDNESDAY FOR LSZ162.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST WEDNESDAY FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KEC
AVIATION...KC
MARINE...KC/KEC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
449 AM EST TUE DEC 3 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 447 AM EST TUE DEC 3 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW RELATIVELY WEAK
ZONAL FLOW ALF OVER THE UPR GRT LKS TO THE N OF FASTER POLAR JET
OVER THE SRN 2/3 OF THE CONUS. THERE ARE 2 SHRTWVS OF NOTE EMBEDDED
IN THIS FLOW. THE FIRST IS MOVING E THRU MN AND CAUSING A BAND OF SN
EXTENDING FM NE MN SEWD OVER WRN LK SUP AND INTO CENTRAL WI AS OF
06Z UNDER AREA OF H85-5 QVECTOR CNVGC. THE AXIS OF HIER
REFLECTIVITIES IN WI APPEARS TO BE ORIENTED ALONG THE MOST
IMPRESSIVE ISENTROPIC ASCENT SHOWN ON THE 290K SFC /H7-75/...WHILE
THE MOST IMPRESSIVE RETURNS IN NE MN ALIGN WITH MOST VIGOROUS H85-5
QVECTOR CNVGC. THE 00Z INL/MPX RAOBS SHOW DEEP MSTR THRU THE DEPTH
OF THE TROP. ELY FEED OF DRIER LLVL AIR ASSOCIATED WITH AREA OF
MOCLR SKIES/HI PRES RDG AXIS STILL OVER FAR ERN UPR MI AND LOCATION
OF SHARPER H85 THERMAL PACKING/ISENTROPIC ASCENT TO THE S HAS SO FAR
LIMITED THE ENE EXTENT OF THE PCPN INTO UPR MI...BUT SN APPEARS
POISED TO SPREAD INTO THE WRN CWA PER LATEST SFC OBS/RADAR IMAGERY.
THE VSBY AT IWD FELL UNDER 2 MILES AT 07Z...AND THE VSBY AS CLOSE AS
ASHLAND IN NW WI IS DOWN TO 1/2 MILE. ENE FLOW DOWN WRN LK SUP MAY
BE ENHANCING THE SN INTO THIS AREA. IN THE AREA OVER WRN MN/MUCH OF
THE DAKOTAS UNDER DNVA/DEEP LYR QVECTOR DVGC BEHIND THE MN SHRTWV...
THERE IS LTL IF ANY PCPN FALLING EVEN THOUGH SKIES REMAIN CLDY WITH
QUITE A BIT OF MID LVL DRYING ABV LLVL MSTR SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. FARTHER TO THE W...THE 2ND MORE IMPRESSIVE
SHRTWV OF INTEREST IS MOVING EWD THRU THE NRN ROCKIES. 12HR H3 HGT
FALLS UP TO 200M AND H3 WIND SPEEDS UP TO 100M IN THE ACCOMPANYING
JET CORE ARE ASSOCIATED WITH THIS MORE IMPRESSIVE DISTURBANCE.
MAIN FCST CONCERNS IN THE SHORT TERM PERIOD ARE POPS/EXPECTED SN
ACCUMS THRU THIS MRNG ASSOCIATED WITH THE FIRST SHRTWV IN MN AND
NEED FOR ANY HEADLINES. FOCUS FOR TNGT TURNS TO POPS AND SN AMOUNTS
THAT WL ACCOMPANY THE APRCH OF THE 2ND STRONGER SHRTWV.
TODAY...AS MN SHRTWV TRACKS TO THE E INTO PERSISTENT SFC RDG AXIS
JUST TO THE E OF UPR MI AND AWAY FM TROF DEEPENING OVER THE W...
AREA OF H85-5 QVECTOR CNVGC IS PROGGED TO DIMINISH SGNFTLY BY 18Z
WITH MID LVL DRYING UNDER DVLPG H85-5 QVECTOR DVGC. EXPECT THE HIER
POPS THIS MRNG OVER THE W AND SCENTRAL UNDER THE SHARPER H85-5
QVECTOR CVNGC/SHARPER 295K ISENTROPIC ASCENT/AREA OF H85-7 FGEN.
GIVEN PRESENCE OF 2.5G/KG SPECIFIC HUMIDITY AT THIS LVL...EXPECT UP
TO 3 INCHES OF SN FOR THE 6-9 HR PERIOD OVER THE SW HALF OF THE CWA.
SINCE THE SN IS LIKELY TO FALL A FOR CLOSER TO 12Z HRS AT IWD...UP
TO 4 INCHES MAY ACCUMULATE THERE BEFORE THE PCPN DIMINISHES TOWARD
NOON. ALTHOUGH THE DGZ IS RATHER NARROW...MODELS SHOW FAIRLY
IMPRESSIVE OMEGA IN THIS LYR THAT MAY INCH SN/WATER RATIOS CLOSER
TO 15:1. CONSIDERING THE LO VSBYS REPORTED AT ASHLAND IN THE ABSENCE
OF LAKE ENHANCEMENT WITH THE LARGER SCALE E WIND...OPTED TO ISSUE A
WINTER WX ADVY FOR GOGEBIC COUNTY THRU MID MRNG. OTRW...UPSLOPE E
WIND OFF LK MI MAY CAUSE STEADIER SN TO LINGER LONGER OVER THE
SCENTRAL. SN WL LIKELY MOVE INTO THE E DURING THE AFTN BUT WL BE MUCH
LIGHTER AS THE DYNAMIC SUPPORT FADES AND HITS DRIER AIR.
TNGT...ALTHOUGH THE EARLY EVNG WL FEATURE DNVA/LARGER SCALE QVECTOR
DVGC LEFT IN THE WAKE OF THE DEPARTING/WEAKENING SHRTWV...FAVORED
CNDN MODEL SHOWS AXIS OF SHARPER H85-7 FGEN SUPPORTING BAND OF SN
NOW OVER SDAKOTA IMPACTING MAINLY THE SRN CWA FOR A COUPLE HRS IN
THE LATER EVNG. THE 00Z GFS/ECWMF SHOW A SIMILAR QPF...SO WENT FOR
HI END LIKELY POPS IN THIS AREA BY LATER IN THE EVNG. OVERALL MODEL
QPF UP TO 0.25 INCH WL SUPPORT A FEW INCHES OF SN IN THIS AREA. HIER
POPS/MORE SN MAY ARRIVE LATE OVER THE W AS THE DYNAMICS IN ADVANCE
OF THE SHRTWV MOVING THRU THE NRN ROCKIES PUSH TOWARD THE AREA. BUT
MODELS DISAGREE ON THE TIMING OF THE ARRIVAL OF THE DEEP LYR QVECTOR
CNVGC AS WELL AS INTENSITY OF THE SFC LO THAT MIGHT ACCOMPANY THE
LARGER SCALE FORCING. THE NAM/LOCAL WRF-ARW MODELS ARE THE MOST
AGGRESSIVE AT DEEPENING THE SFC LO AND BRINGING MORE PCPN FARTHER E.
BUT SINCE THE MAIN SHRTWV REMAINS SO FAR TO THE W THRU THE NGT...
SUSPECT THE SLOWER/WEAKER CNDN MODEL IS ON THE RIGHT TRACK. SO WENT
NO HIER THAN LIKELY POPS OVER THE FAR W FOR NOW. THE THERMAL FIELDS
FM THE CNDN MODEL INDICATE ENUF WARM AIR WL ARRIVE TO CAUSE THE SN
TO MIX WITH RA OVER THE FAR SCENTRAL.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 447 AM EST TUE DEC 3 2013
CONTINUED CHALLENGING FORECAST IN STORE FOR WEDNESDAY THROUGH
WEDNESDAY NIGHT TIME FRAME AS A WINTER WEATHER SYSTEM TAKES AIM AT
THE UPPER GREAT LAKES. VERY COLD AIR IS EXPECTED TO BUILD IN ON THE
BACK SIDE OF THIS SYSTEM ALLOWING FOR VERY COLD TEMPERATURES FRIDAY
NIGHT THROUGH SATURDAY NIGHT.
WEDNESDAY INTO WEDNESDAY NIGHT...SITUATION LOOKS A BIT BETTER FROM A
FORECASTING STANDPOINT AS MODELS ARE COMING INTO BETTER AGREEMENT
WITH RESPECT TO THE HANDLING OF THE LOW PRESSURE SYSTEM POISED TO
AFFECT THE AREA THROUGH THIS TIME PERIOD. THE 00Z RUN OF THE NAM AND
GFS ARE FINALLY ALIGNING BETTER WITH THE MORE CONSISTENT
EC/GEM...ALTHOUGH THEY ARE A TOUCH FASTER AT SHIFTING THE LOW INTO
THE UPPER PENINSULA. AS OF 12Z/04 EACH OF THE MODELS ARE IN GOOD
AGREEMENT IN PLACING THE SURFACE LOW OVER SW WISCONSIN WITH VERY
SIMILAR INTENSITIES. THE UPPER LEVEL 500MB CLOSED LOW IS PROGGED TO
BE POSITIONED FARTHER NORTHWEST OVER NORTHWESTERN MN...INDICATING
THE POTENTIAL FOR ADDITIONAL INTENSIFICATION OF THE SURFACE LOW. AT
THAT TIME ISENTROPIC UPGLIDE IS EXPECTED TO CONTINUE AS SHOWN BY
ANALYZING MOISTURE AND MOISTURE TRANSPORT ON A 295K PRESSURE
ISOSURFACE. SOUNDINGS AROUND 12Z/04 INDICATE THAT MOST OF THE
PRECIPITATION EAST OF A MQT TO IMT LINE WILL LIKELY BE IN THE FORM
OF RAIN AS A FAIRLY DEEP WARM LAYER EXISTS IN THE BOUNDARY LAYER.
WEST OF THAT LINE ATMOSPHERIC PROFILES ARE SUCH THAT THE
PRECIPITATION SHOULD REMAIN IN THE FORM OF SNOW. ALSO AT THIS TIME
FORCING IN THE DGZ SEEMS FAIRLY LIMITED...HOWEVER...THIS WILL CHANGE
THROUGH THE DAY. THE LOW IS PROGGED TO BE OVER SOUTH CENTRAL WI BY
18Z/04. AS THIS LOW CONTINUES TO APPROACH DURING THIS TIME PERIOD
INCREASED MOISTURE AND FORCING IN THE DGZ IS EXPECTED TO INCREASE
ALLOWING FOR A STEADY INCREASE IN SNOWFALL INTENSITY DURING THE
AFTERNOON HOURS. BETWEEN 00Z/05 AND 06Z/05 THE LOW IS PROGGED TO
SHIFT NORTH AND EASTWARD INTO THE EAST CENTRAL PORTION OF THE UPPER
PENINSULA. INCREASED SNOWFALL RATES ARE EXPECTED TO CONTINUE DURING
THAT TIME PERIOD AS WELL...AS CONTINUED MOISTURE AND LIFT ARE
PROGGED TO BE COLLOCATED IN THE DGZ AS SHOWN BY ANALYZING 1000-500MB
RH AS WELL AS QCONV IN THE 700-500 DGZ LAYER AS IDENTIFIED USING
ATMOSPHERIC PROFILES OF THE EC/GEM. THE WESTERN HALF OF THE UPPER
PENINSULA LOOKS TO ALSO BE IN A FAVORED LOCATION FOR HEAVY SNOWFALL
AS THIS REGION IS IN THE FAVORED LEFT EXIT REGION OF AN UPPER LEVEL
JET. THE MAIN CAVEAT HERE IS THE NEW UNCERTAINTY WITH PRECIPITATION
TYPE WHICH WAS INTRODUCED BY THE 00Z EC/GEM/UKMET WHICH PULLS THE
SURFACE LOW MUCH FARTHER TO THE WEST...WHICH TAKES THE LOW VERY NEAR
WHERE THE PREVIOUS GFS MODELS WERE TAKING IT OVER THE PAST COUPLE OF
DAYS. THIS WOULD SHIFT THE RAIN SNOW LINE FARTHER WEST...POSSIBLY
REDUCING SNOWFALL TOTALS. HAVE DECIDED TO CONTINUE WITH AN UPDATED
SPS BASED ON COORDINATION WITH SURROUNDING OFFICES...AS CONFIDENCE
IS NOT HIGH ENOUGH AT THIS POINT TO GO WITH A HEADLINE.
THURSDAY THROUGH SATURDAY...BETWEEN 12Z/05 AND 18Z/05 THE SURFACE
LOW IS PROGGED TO SHIFT NORTHEASTWARD TO JUST SOUTH OF JAMES
BAY...TAKEN THE BETTER SYNOPTIC FORCING OUT OF THE AREA. AT THE SAME
TIME A DEEP TROUGH DIGGING INTO THE NORTHERN PLAINS WILL BEGIN TO
INFLUENCE THE WEATHER IN THE UPPER PENINSULA. WINDS WILL BECOME
WESTERLY TO WEST NORTHWESTERLY IN THE RETURN FLOW ON THE BACK SIDE
OF THE LOW PRESSURE SYSTEM. THIS WILL ALLOW LAKE EFFECT SNOW DEVELOP
IN THE SNOWBELTS FAVORED WITH THE SAID WIND DIRECTION. 850MB
TEMPERATURES ARE EXPECTED TO DROP FROM NEAR -14C 12/05 TO AROUND
-22C 12Z/07. THESE TEMPERATURES ARE MORE THAN FAVORABLE FOR LES
GIVEN LAKE SURFACE TEMPERATURES AROUND 4C TO 5C...CREATING DELTA T
VALUES BETWEEN 18 AND 27 DEGREES THROUGH THIS TIME PERIOD.
WINDS...AGAIN...LOOK TO BE FAVORABLE WITH SURFACE TO 850MB WINDS
REMAINING OUT OF THE WEST...AND WELL WITHIN THE 30 DEGREE TOLERANCE
FOR LES. IT APPEARS AS IF THE TIME FRAME FOR HEAVIER LES WOULD OCCUR
THURSDAY EVENING INTO FRIDAY MORNING AS INVERSION HEIGHTS INCREASE
TO AROUND 8-9KFT AFTER ADJUSTING FOR LAKE SURFACE TEMPERATURES. THE
MOISTURE IS COLLOCATED WITH THE DGZ WHICH WOULD BE MORE FAVORABLE
FOR SNOWFLAKE PRODUCTION. FRIDAY AFTERNOON THROUGH SATURDAY
INVERSION HEIGHTS ARE EXPECTED TO BECOME MORE SHALLOW AS
TEMPERATURES ALSO BEGIN TO RAPIDLY DROP AS THE NEXT TROUGH AXIS
PRESSES INTO THE AREA. THESE COLDER TEMPERATURES WILL PRESS THE DGZ
DOWN TO THE VERY LOWEST LEVELS OF THE ATMOSPHERE. WHILE IT IS LIKELY
THAT SNOW WILL CONTINUE TO FALL THROUGH THE FRIDAY AFTERNOON INTO
SATURDAY TIME PERIOD...SNOW PRODUCTION WILL BE LIMITED AS THE
MOISTURE IS MAINLY OUTSIDE OF THE DGZ. TEMPERATURES THIS WEEKEND
WILL BE WELL BELOW NORMAL WITH TEMPERATURES DROPPING INTO THE TEENS
BELOW ZERO FRIDAY NIGHT INTO SATURDAY NIGHT...ESPECIALLY OVER THE
WEST HALF. HIGH TEMPERATURES WILLS STRUGGLE TO GET OUT OF THE SINGLE
DIGITS OVER WESTERN AREAS. WIND CHILLS THIS WEEKEND WILL BECOME
DANGEROUSLY COLD WITH READINGS DROPPING TO AROUND 30 BELOW ZERO OVER
THE INTERIOR WEST.
SATURDAY NIGHT THROUGH MONDAY...A SURFACE HIGH PRESSURE SYSTEM IS
PROGGED TO MOVE INTO THE UPPER GREAT LAKES REGION AS UPPER LEVEL
FLOW BECOMES SLIGHTLY MORE ZONAL SATURDAY NIGHT THROUGH SUNDAY. THIS
ALONG WITH DRYER AIR WILL ALLOW LAKE EFFECT SNOT TO DIMINISH. LOW
PRESSURE WILL THEN BUILD BACK INTO THE AREA SUNDAY NIGHT INTO
MONDAY. WINDS WILL BECOME SOUTH TO SOUTHWESTERLY DURING THIS TIME
PERIOD WHILE TEMPERATURES ALOFT AT 850MB LINGER AROUND -15C WHICH
WILL HELP LES TO DEVELOP OVER THE FAR EASTERN UPPER PENINSULA AS THE
WIND FLOW WOULD BE DIRECTLY ACROSS THE WARM WATERS OF LAKE MICHIGAN.
THE BEST CHANCE OF THIS HAPPENING WOULD BE SUNDAY NIGHT INTO MONDAY
MORNING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1228 AM EST TUE DEC 3 2013
DISTURBANCE APPROACHING FROM THE NRN PLAINS WILL SPREAD -SN FROM W
TO E ACROSS THE AREA TONIGHT. WITH THE ONSET OF THE -SN...MARGINAL
VFR CONDITIONS WILL INITIALLY LOWER TO MVFR AND THEN TO IFR SEVERAL
HRS LATER. UPSLOPE E-SE FLOW AT KCMX/KSAW WILL LIKELY ALSO AID IN
DETERIORATING CONDITIONS AT THOSE SITES LATE TONIGHT INTO TUE
MORNING. MAY SEE SOME IMPROVEMENT AT KIWD TUE MORNING AND AT
KSAW/KCMX TUE AFTERNOON AS STEADIER -SN SHIFTS E AND NE. ANOTHER
DISTURBANCE APPROACHING FROM THE PLAINS WILL BRING IN ANOTHER SHOT
OF SNOW LATE TUE EVENING WITH CONDITIONS DETERIORATING TO IFR AGAIN.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 AM EST TUE DEC 3 2013
EXPECT INCREASING E WINDS THRU TONIGHT AS THE PRES GRADIENT TIGHTENS
OVER THE UPPER LAKES BETWEEN HI PRES OVER NORTHERN ONTARIO AND LO
PRES TAKING SHAPE IN THE PLAINS. THE STRONGEST WINDS WILL BE OVER
WESTERN LAKE SUPERIOR...WHERE THE TERRAIN SURROUNDING THE LAKE
FUNNELS AND ENHANCES THE LARGER SCALE WINDS. MAINTAINED GOING GALE
WARNINGS FOR THE TWO WESTERN ZONES AND MENTIONED SOME GALE FORCE
GUSTS OVER THE CENTRAL AS WELL THIS AFTERNOON THRU TONIGHT.
LOW PRESSURE WILL MOVE ACROSS THE UPPER GREAT LAKES LATE WED THROUGH
THU MORNING. IN THE WAKE OF THE LOW...VERY COLD AIR ADVECTING OVER
THE RELATIVELY WARM WATERS WILL INCREASE INSTABILITY AND RESULT IN W
TO NW GALES AT TIMES FOR PORTIONS OF LAKE SUPERIOR WED NIGHT/THU.
CONTINUED FLOW OF VERY COLD AIR MAY RESULT IN A FEW GALE FORCE GUSTS
INTO SATURDAY BEFORE HIGH PRESSURE BUILDS IN SUNDAY. THIS HIGH
PRESSURE SYSTEM WILL MOVE DIRECTLY OVERHEAD BY SUNDAY AFTERNOON
ALLOW WINDS TO BECOME LIGHT AND VARIABLE. BUILDING WAVES AND THE
ARRIVAL OF THE ARCTIC AIR WILL CAUSE AN INCREASING FREEZING SPRAY
POTENTIAL FOR THE LAST HALF OF THE WORK WEEK AND INTO THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 11 AM CST THIS MORNING FOR MIZ009.
LAKE SUPERIOR...
GALE WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 10 AM
EST /9 AM CST/ WEDNESDAY FOR LSZ162.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST WEDNESDAY FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KEC
AVIATION...VOSS
MARINE...KC/KEC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
341 AM EST TUE DEC 3 2013
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 341 AM EST TUE DEC 3 2013
A WARM FRONT MOVING THROUGH LOWER MICHIGAN WILL BRING LIGHT SNOW
POSSIBLY MIXED WITH SLEET AND FREEZING RAIN THIS MORNING. WE DON/T
EXPECT MUCH IF ANY ACCUMULATION. HOWEVER A FEW ROADS COULD BECOME
SLICK. THE PCPN WILL BECOME LIGHT RAIN THIS AFTERNOON AS WARMER AIR
MOVES INTO THE REGION.
A STRONG COLD FRONT WILL MOVE THROUGH WEDNESDAY NIGHT BRINGING AN
ABRUPT END TO THE 50 DEGREE TEMPERATURES EXPECTED WEDNESDAY. SNOW
SHOWERS AND HIGHS IN THE 20S ARE EXPECTED FRIDAY THROUGH THE
WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
FORECAST CONCERNS DEAL WITH MIXED PCPN MAINLY THIS MORNING.
LATEST RADAR SHOWS A BAND OF PCPN STRETCHING FROM OCEANA COUNTY
SOUTHEAST TOWARD NW OHIO MOVING NEWD THROUGH THE CWA. MOST OF THIS
IS LIGHT SHOW BUT LOCAL OBS HAVE SHOWN SOME SLEET TOO. THIS WAS
CORROBORATED BY DUAL POL. LATEST HRRR AND FCST SOUNDINGS SUGGEST
SOME
LIGHT FREEZING RAIN IS POSSIBLE TOO THIS MORNING BEFORE TEMPS WARM
UP ENOUGH TO RESULT IN LIGHT RAIN. PCPN IS FAIRLY LIGHT AND ANY
ACCUMS SHOULD REMAIN LESS THAN AN INCH. THAT SAID...A FEW ROADS MAY
BECOME SLICK.
A WARM FRONT WILL CONTINUE TO PUSH NORTH THROUGH THE CWA TONIGHT. H8
TEMPS RISING TO 7C SHOULD RESULT IN SFC TEMPS IN THE 50S TOMORROW.
MODELS CONTINUE TO BE AT ODDS ON COLD FRONTAL TIMING. WE/LL BE
CONSISTENT THOUGH IN FOLLOWING THE SLOWER ECMWF DUE TO THE OCCLUDING
NATURE OF THE SYSTEM. THAT MEANS A FROPA WEDNESDAY NIGHT. HIGHS
THURSDAY WILL BE IN THE MID 30S. LIGHT SNOW SHOWERS POSSIBLE
THURSDAY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
TWO MAIN HEADLINES OF THE LONG TERM REMAIN THE COLD AND LAKE EFFECT
SNOW SHOWERS. THE COLD MAY BE THE BIGGER STORY AS THE LAKE EFFECT
LOOKS TO BE SOMEWHAT MOISTURE DEPLETED.
COLD AIR ADVECTION WILL BE IN FULL SWING THURSDAY NIGHT AS WE BEGIN
THE LONG TERM WITH THE LOW MOVING AWAY ACROSS ONTARIO. DELTA T/S
WILL BE IN THE MIDDLE TEENS...PROVIDING DECENT INSTABILITY. MOISTURE
LOOKS LIMITED SO NOT EXPECTING ANYTHING IN THE WAY OF SIGNIFICANT
LAKE EFFECT. MINOR ACCUMULATIONS AT BEST.
THAT REALLY REMAINS THE CASE FOR FRIDAY THROUGH SATURDAY. CONTINUED
COLD AIR ADVECTION WILL PUSH DELTA T/S INTO THE LOWER 20S C...BUT
MOISTURE REMAINS A LIMITING FACTOR. WE NEVER DEEPLY PLUNGE INTO
CYCLONIC FLOW TO THE NORTH SIDE OF THE UPPER JET AXIS...INSTEAD
REMAINING IN A BROAD SOUTHWEST TO WEST FLOW. 1000-700MB RH VALUES
FROM FRIDAY THROUGH SATURDAY REMAIN IN THE 40-60 PCT RANGE WHICH IS
NOT IDEAL. 20-40 PCT CHANCES FOR SNOW SHOWERS THURSDAY NIGHT THROUGH
SATURDAY SEEM WARRANTED. AT THIS POINT NOT EXPECTING ANY BIG
ACCUMULATIONS...JUST PERSISTENT LIGHT SNOW SHOWERS.
LOW PRESSURE IS FORECAST BY THE ECMWF (STILL THE MODEL OF CHOICE
TONIGHT) TO SWING NORTH THROUGH THE AREA SUNDAY NIGHT INTO MONDAY
WHICH BRINGS A GENERAL LIGHT SYNOPTIC SNOW TO THE AREA.
LOWS IN THE TEENS THROUGH THE PERIOD WITH HIGHS IN THE 20S WILL BE
COMMON. THIS IS COLDER THAN NORMAL...BUT BY NO MEANS RARE FOR EARLY
DECEMBER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1058 PM EST MON DEC 2 2013
THE MAIN AVIATION ISSUE TONIGHT IS WITH THE LIGHT MIXTURE OF
SNOW... FREEZING RAIN.. AND SLEET WHICH IS EXPECTED FROM ROUGHLY
08Z TO 14Z. THIS WILL IMPACT THE MORNING RUSH WITH THE LIKELIHOOD
FOR ICING AS WELL AS SLIPPERY RUNWAY CONDITIONS. THE ICING THREAT
IS EXPECTED TO END BY 15Z AS SFC TEMPS WARM ABOVE FREEZING AND THE
PRECIPITATION CHANGES TO ALL LIGHT RAIN.
WIDESPREAD VFR CONDITIONS AT 04Z WILL LOWER FAIRLY QUICKLY INTO
THE MVFR/IFR CATEGORY 06Z-09Z AS THE LIGHT WINTRY MIX DEVELOPS AND
SPREADS EAST/NORTHEAST. PRECIPITATION WILL CHANGE TO ALL RAIN BY
MID MORNING TUESDAY ALTHOUGH WIDESPREAD IFR CONDITIONS ARE EXPECTED
FOR TUESDAY AFTERNOON AND EVENING DUE TO PERSISTENT LOW CIGS/VSBYS
IN LINGERING LIGHT RAIN/FOG.
&&
.MARINE...
ISSUED AT 341 AM EST TUE DEC 3 2013
SOUTH TO SOUTHEAST WINDS WILL INCREASE TO 15 TO 25 KNOTS TODAY. THE
OFFSHORE NATURE OF THE WINDS SHOULD PRECLUDE WAVES FROM GETTING
HIGHER THAN 3 FEET.
&&
.HYDROLOGY...
ISSUED AT 341 AM EST TUE DEC 3 2013
NO HYDRO ISSUES TODAY. HOWEVER THE ARCTIC AIR EXPECTED BY THE END OF
THE WEEK COULD CAUSE ICE TO DEVELOP ON STREAMS AND RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...MEADE
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1230 AM EST TUE DEC 3 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 506 PM EST MON DEC 2 2013
MAIN FCST CONCERN IN THE SHORT TERM IS SNOW ACCUMULATIONS WITH A
RATHER PERSISTENT -SN REGIME SETTING UP.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW RELATIVELY ZONAL FLOW
ACROSS THE NRN PLAINS AND UPPER GREAT LAKES. ONE SHORTWAVE HAS MOVED
E OF UPPER MI...ANOTHER IS OVER THE ERN DAKOTAS/WRN MN WHILE A
WELL-DEFINED MID LEVEL LOW IS NOTED OVER THE PACIFIC NW. PCPN
TONIGHT/EARLY TUE WILL BE ASSOCIATED WITH THE SHORTWAVE HEADING INTO
MN...THEN ANOTHER ROUND OF FORCING MAY BEGIN TO OVERSPREAD THE AREA
LATER TUE AS PACIFIC NW SYSTEM EMERGES INTO THE NRN PLAINS.
RELATIVELY MODEST ISENTROPIC ASCENT/WAA REGIME AHEAD OF THE WRN MN
SHORTWAVE IS GENERATING AN AREA OF -SN FROM NE MN ACROSS FAR WRN
UPPER MI INTO NW WI. ANOTHER BAND OF SNOW IS LINED UP JUST AHEAD OF
THE SHORTWAVE TROF AXIS. AS SHORTWAVE AND ASSOCIATED ISENTROPIC
ASCENT SHIFT E...EXPECT -SN TO SPREAD GRADUALLY E ACROSS ROUGHLY THE
W HALF OF UPPER MI TONIGHT. BETTER ASCENT GENERALLY OCCURS OVER FAR
W INTO SRN UPPER MI...BUT TENDS TO WEAKEN WITH TIME...ESPECIALLY
FARTHER E AND NE...AS SHORTWAVE WEAKENS. MAY END UP WITH A PERIOD OF
STEADIER -SN OVER THE FAR W THIS EVENING UNDER WAA REGIME AND THEN
THERE WILL BE ANOTHER PUSH OF STEADIER -SN AS BAND OF SNOW JUST
AHEAD OF SHORTWAVE TROF AXIS SWINGS INTO THE AREA. IN THE END...
GREATEST SNOW ACCUMULATIONS TONIGHT THRU TUE MORNING WILL OCCUR OVER
THE FAR W AND TO SOME EXTENT TOWARD SCNTRL UPPER MI. UTILIZATION OF
MIXING RATIOS ON THE 290K SFC (ROUGHLY BTWN 700-750MB) SUGGESTS
POTENTIAL FOR 4-6 INCH ACCUMULATIONS ACROSS THE W AND SCNTRL TONIGHT
THRU TUE MORNING. HOWEVER...WITH A LACK OF FOCUSED UPWARD MOTION
THRU A RELATIVELY HIGH/NARROW DGZ...SNOW RATIOS WILL BE ON THE LOW
SIDE...PROBABLY SOMETHING LIKE 10-12 TO 1. ALSO...SINCE ISENTROPIC
ASCENT IS NEVER ESPECIALLY STRONG...SNOW ACCUMULATIONS WILL LIKELY
END UP BLO ADVY CRITERIA. ONLY PLACE THAT WILL BE CLOSE TO ADVY IS
IN THE KIWD VCNTY. FOR NOW...WILL HOLD OFF ANY HEADLINES AND MONITOR
TRENDS THIS EVENING. OVERALL TONIGHT/TUE MORNING...EXPECT MORE OF A
PERSISTENT -SN WITH NOT MUCH IN THE WAY OF NOTABLY HEAVIER PERIODS
OF SNOW.
ON TUE...AREA OF DIMINISHING -SN ASSOCIATED WITH WEAKENING SHORTWAVE
WILL CONTINUE TO LIFT N AND E. MEANWHILE...SYSTEM CURRENTLY OVER THE
PACIFIC NW WILL EMERGE OVER THE NRN PLAINS. AS IT DOES SO...
ISENTROPIC ASCENT MAY STRENGTHEN AGAIN IN THE AFTN OR INTO TUE
EVENING...THOUGH THERE IS SOME DISAGREEMENT ON HOW STRONG THE
ISENTROPIC ASCENT WILL BE. SO...AFTER DIMINISHING -SN INTO THE AFTN
HRS...-SN MAY PICK UP AGAIN FROM THE SW LATER IN THE AFTN. MAY SEE
AN INCH OR SO OF SNOW LATE IN THE DAY TOWARD THE WI BORDER.
SPECIAL WEATHER STATEMENT HAS BEEN UPDATED TO REFLECT THE LATEST
THINKING ON THE WINTRY WEATHER EXPECTED OVER THE NEXT FEW DAYS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 513 PM EST MON DEC 2 2013
SIGNIFICANT SNOWFALL IS POSSIBLE TUESDAY NIGHT INTO THURSDAY MORNING
FOR WEST AND CENTRAL UPPER MICHIGAN
AND THE SAGA CONTINUES...MODELS DISAGREEING ON HOW AND WHEN THE LOW
PRESSURE SYSTEM WILL CROSS UPPER MI. THOUGH ALL HAVE SIMILAR TRACKS
WITH SLIGHT DIFFERENCES...THE 12Z GFS/NAM AND THE 12Z GEM/12Z ECMWF
ARE WIDELY DIFFERENT IN TERMS OF TIMING.
ON THE TRACK OVERALL...MODELS TAKE THE LOW FROM THE CENTRAL PLAINS
INTO THE JAMES BAY/NORTHERN ONTARIO REGION. THE 12Z GEM/12Z
UKMET/12Z ECMWF TAKE THE LOW FURTHEST SOUTHEAST...MOVING FROM
SOUTHEASTERN WI TO EASTERN UPPER MI...THEN INTO ONTARIO SOUTH OF
JAMES BAY. THE GFS/NAM TAKE THE LOW TRACK FROM WESTERN WI INTO
CENTRAL UPPER MI...THEN JUST SOUTH OF JAMES BAY AND NORTHEAST OF
LAKE SUPERIOR.
TIMING WISE...THE 12 GFS/NAM HAVE A MUCH QUICKER SOLUTION THAN THE
ECMWF/GEM...AND THE UKMET IS SLIGHTLY SLOWER THAN ALL. FOR
EXAMPLE...WHEN THE GFS/NAM HAVE THE LOW SOUTH OF JAMES BAY...THE 12Z
ECMWF/12Z GEM ARE JUST CROSSING IT OVER LAKE SUPERIOR/EASTERN UPPER
MI. THE UKMET HAS IT OVER SOUTHEASTERN UPPER MI/NORTHERN LAKE MI.
OVERALL...SINCE CONSISTENCY WISE THE ECWMF SEEMS STEADIER...AND
BECAUSE OFTEN TIMES THE GFS SEEMS TO RUSH THINGS THROUGH/AMPLIFY
THINGS...OPTED TO LEAN TOWARDS THE SLOWER GEM/ECMWF SOLUTION FOR
TIMING. FOR THE EXACT TRACK OF THE LOW...USED A 12Z GEM/12Z ECMWF
COMPROMISE.
USING THE CHOSEN MODEL TRACKS/TIMING...A BROAD AREA OF 850MB WAA AND
ISENTROPIC ASCENT ON THE 290K SFC WILL BRING WIDESPREAD
PRECIPITATION ACROSS UPPER MICHIGAN AS THE SYSTEM APPROACHES TUESDAY
NIGHT THROUGH WEDNESDAY MORNING. SOUNDINGS SUGGEST THIS FIRST BURST
OF PRECIPITATION WILL BE IN THE FORM OF SNOW. BY WEDNESDAY
AFTERNOON...AS THE LOW REACHES IOWA AND ILLINOIS/SOUTHERN WI...WARM
MOIST AIR WRAPPING AROUND THE SURFACE LOW DEVELOPS A 700MB FGEN BAND
THAT ALIGNS ITSELF SOUTHWEST TO NORTHEAST...FROM SOUTHEASTERN MN TO
JUST NORTHEAST OF LAKE SUPERIOR...ACROSS THE WESTERN AND CENTRAL CWA.
BY 00Z THURSDAY SLIGHT DIFFERENCES IN THE TRACK OF THE LOW BETWEEN
THE GEM/ECMWF START TO AFFECT THE TEMPERATURE/PTYPE FORECAST. THE
12Z ECMWF CENTERS THE LOW OVER CENTRAL WI...WHICH BRINGS A NOSE OF
WARMER AIR SLIGHTLY FURTHER NORTH AND CENTRAL. THIS WOULD BRING
CHANCES FOR MIXED PRECIPITATION/RAIN INTO THE NORTH CENTRAL AND
EAST. THE GEM KEEPS THE LOW SOUTHEAST...CENTERED OVER SOUTHEASTERN
WI BY 00Z THUR AND NOT QUITE PULLING THAT WARMER AIR AROUND INTO THE
CENTRAL. THIS WOULD KEEP THE WEST AND NORTH CENTRAL ALL SNOW...AND
THE EAST A MIX/RAIN. BY 12Z THURSDAY HOWEVER...THE MODELS ALL AGREE
ON SNOW BEING THE PTYPE. THE EXACT TRACK WILL AFFECT WHAT TYPE OF
SNOWFALL AMOUNTS WE SEE. AGAIN...WENT WITH AN ECMWF/GEM COMPROMISE
FOR TEMPS/PTYPE...WHICH KEEPS THE PRECIPITATION SNOW FOR A MAJORITY
OF THE FORECAST AREA...ONLY MIXING/RAIN ACROSS THE FAR SOUTHEASTERN
CWA. OVERALL...ACCUMULATIONS COULD BE OVER 6-8 INCHES ACROSS THE
WEST AND CENTRAL U.P. FROM TUESDAY NIGHT INTO THURSDAY MORNING.
AS THE LOW MOVES OFF INTO ONTARIO JUST NORTHEAST OF LAKE SUPERIOR
BETWEEN 06Z AND 12Z THURSDAY...UPPER MICHIGAN IS QUICKLY BROUGHT
INTO AN AREA OF STRONG CAA ON WEST TO NORTHWEST WINDS. 850MB TEMPS
QUICKLY DIP INTO THE -15 TO -20C RANGE IN THE WAKE OF THE LOW...AND
ON ON WEST TO NORTHWEST WINDS LAKE EFFECT CHANCES QUICKLY BECOME THE
MAIN CONCERN. GRADUALLY AS THE LOW HOVERS OVER JAMES BAY AREA FRIDAY
AND SATURDAY...850MB TEMPS CONTINUE TO DROP...REACHING AS LOW AS
-22C...WITH THE KEWEENAW AND WESTERN UPPER MI IN THE COLDEST OF THAT
AIR. THIS WILL BRING VERY COLD TEMPERATURES TO UPPER MICHIGAN FRIDAY
NIGHT THROUGH SATURDAY NIGHT...WITH WIND CHILLS AS LOW AS -25C IN
SOME PLACES OUT WEST.
SATURDAY AND SUNDAY...HIGH PRESSURE STEADILY EXPANDING FROM THE
CANADIAN PRAIRIE...ACROSS THE GREAT LAKES...AND INTO THE ATLANTIC.
GENERALLY IN THIS TIME FRAME...WINDS ARE WESTERLY TO
NORTHWESTERLY...850MB TEMPS RANGE FROM -22C TO -15C...AND THERE ARE
SHORTWAVES ROUNDING THE LOW OVER JAMES BAY. THESE SHORTWAVES WILL
SERVE TO ASSIST THE EXPECTED LAKE EFFECT SNOW SHOWERS DURING THESE
PERIODS...WITH CHANCES LESSENING AS THE LOW DEPARTS AND THE HIGH
STRENGTHENS. SNOW ACCUMULATIONS COULD BE HAMPERED HOWEVER...AS THE
DGZ DIPS CLOSER TO THE GROUND WITH THE EXTREME COLD. ON MONDAY
MODELS DISAGREE SLIGHTLY ON ANOTHER AREA OF LOW PRESSURE MOVING INTO
THE GREAT LAKES REGION...SO KEPT CONSENSUS PRECIPITATION CHANCES
BEGINNING ACROSS THE NON-LAKE EFFECT AREAS AS IT APPROACHES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1228 AM EST TUE DEC 3 2013
DISTURBANCE APPROACHING FROM THE NRN PLAINS WILL SPREAD -SN FROM W
TO E ACROSS THE AREA TONIGHT. WITH THE ONSET OF THE -SN...MARGINAL
VFR CONDITIONS WILL INITIALLY LOWER TO MVFR AND THEN TO IFR SEVERAL
HRS LATER. UPSLOPE E-SE FLOW AT KCMX/KSAW WILL LIKELY ALSO AID IN
DETERIORATING CONDITIONS AT THOSE SITES LATE TONIGHT INTO TUE
MORNING. MAY SEE SOME IMPROVEMENT AT KIWD TUE MORNING AND AT
KSAW/KCMX TUE AFTERNOON AS STEADIER -SN SHIFTS E AND NE. ANOTHER
DISTURBANCE APPROACHING FROM THE PLAINS WILL BRING IN ANOTHER SHOT
OF SNOW LATE TUE EVENING WITH CONDITIONS DETERIORATING TO IFR AGAIN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 506 PM EST MON DEC 2 2013
AS LOW PRES BEGINS TO ORGANIZE IN THE PLAINS AND HIGH PRES BUILDS
ACROSS CNTRL CANADA AND INTO NRN ONTARIO...E TO SE WINDS WILL BE ON
THE INCREASE TONIGHT...AND E WINDS WILL INCREASE FURTHER TUE. EXPECT
WINDS TO REACH GALE FORCE OVER WRN LAKE SUPERIOR TUE AFTN THU WED
MORNING AS TERRAIN SURROUNDING THE LAKE ENHANCES THE E FLOW. THE LOW
WILL MOVE ACROSS THE UPPER GREAT LAKES LATE WED. IN THE WAKE OF THE
LOW...VERY COLD AIR ADVECTING OVER THE RELATIVELY WARM WATERS WILL
INCREASE INSTABILITY AND RESULT IN W TO NW GALES AT TIMES FOR
PORTIONS OF LAKE SUPERIOR WED NIGHT/THU. CONTINUED FLOW OF VERY COLD
AIR MAY RESULT IN PERIODIC GALES EVEN THRU FRI/SAT. BUILDING WAVES
AND THE ARRIVAL OF THE ARCTIC AIR WILL ALSO CAUSE INCREASING
FREEZING SPRAY LATE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 10 AM
EST /9 AM CST/ WEDNESDAY FOR LSZ162.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST WEDNESDAY FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...MCD
AVIATION...VOSS
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS HASTINGS NE
600 PM CST WED DEC 4 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 257 PM CST WED DEC 4 2013
AN ARCTIC AIRMASS HAS SETTLED ACROSS THE NORTHERN AND CENTRAL
PLAINS...AND H85 TEMPS ARE ON THE ORDER OF 2 TO 3 STANDARD
DEVIATIONS BELOW NORMAL FOR THIS TIME OF YEAR. TEMPERATURES THIS
AFTERNOON HAVE STRUGGLED IN THE ARCTIC AIR AND READINGS AVERAGE IN
THE TEENS/20S ATTM. WINDS CONTINUE TO REMAIN STEADY/GUSTY IN A
TIGHT PRESSURE GRADIENT WITH A DEPARTING SFC LOW ACROSS EASTERN
IOWA AND A 1035MB SURFACE HIGH BUILDING SOUTHEAST FM MONTANA. THE
COMBINATION OF THE GUSTY WINDS AND COLD TEMPS HAVE RESULTED IN
WINDS CHILLS IN THE SINGLE DIGITS THIS AFTERNOON. SNOW FLURRIES
ACROSS OUR EASTERN ZONES CONTINUE WILL CONTINUE TO DIMINISH AS WE
HEAD THRU THE REMAINDER OF THE AFTN IN A SUBSIDENT/CLEARING AREA.
THIS EVENING...A 150KT H25 JET EMERGES FROM THE CENTRAL ROCKIES
AND CROSSES THRU NEBRASKA AND A MID LEVEL TROUGH TRANSLATES ACROSS
THE CENTRAL PLAINS. COLD AIR IS REINFORCED WITH THIS NEXT TROUGH
MOVING THRU THIS EVENING AND A BAND OF MID LEVEL FRONTOGENESIS IS
PROGGED ACROSS OUR SOUTHERN ZONES. IN FAVORABLE JET DYNAMICS AND
PRESENCE OF THE FRONTOGENESIS...A NARROW CORRIDOR OF BANDED
SNOWFALL IS EXPECTED TO DEVELOP DURING THE EVENING. MODELS ARE NOT
IN COMPLETE AGREEMENT ON WHERE THIS BAND WILL SET UP WITH THE GFS
THE FARTHEST NORTH WITH THE BAND...THE 12Z NAM WAS THE FARTHEST
SOUTH WITH THE BAND BUT HAS TRENDED NORTHWARD WITH THE 18Z RUN.
EARLIER RUNS OF THE RAP WERE MORE SIMILAR TO THE CURRENT 18Z
NAM...HOWEVER THE LATEST RUNS OF THE RAP HAVE TRENDED FARTHER
SOUTH INTO CENTRAL KANSAS WITH THE POSITION. THIS BEING
SAID...NORTH CENTRAL KANSAS IS STILL THE MOST FAVORABLE LOCATION
FOR SNOWFALL THIS EVENING. POPS HAVE BEEN INCREASED AND WHERE BAND
SETS UP...SOME HALF INCH SNOWFALL AMOUNTS OR SO ARE NOT OUT OF THE
QUESTION. FARTHER NORTH OF THE BAND...FLURRIES ARE POSSIBLE UNTIL
THE MID LEVEL TROUGH AXIS PASSES TO THE EAST BY AROUND MIDNIGHT OR
SHORTLY THEREAFTER.
OVERNIGHT TEMPERATURES WILL REMAIN FRIGID AND CLOUDS BEGIN TO SCOUR
BEFORE DAYBREAK. HAVE WENT WITH LOW TEMPS IN THE SINGLE DIGITS
ABOVE ZERO TONIGHT AND WHEN COMBINED WITH THE STEADY NORTHWESTERLY
WINDS...WIND CHILL READINGS WILL DROP TO ROUGHLY 8 TO 18 DEGREES
BELOW ZERO ACROSS OUR CWA. THE COLDEST READINGS WILL BE ACROSS OUR
NW ZONES...AND THE 18 BELOW VALUES REMAIN SHY OF WIND CHILL ADVISORY
CRITERIA SO WILL HOLD OFF ON HEADLINE AND CONTINUE TO MENTION COLD
WIND CHILLS IN THE HWO.
THE ARCTIC AIRMASS WILL REMAIN IN PLACE ON THURSDAY...WITH FRIGID
-18C AIR SETTLING IN AT H85. THE SFC RIDGE AXIS WILL CONTINUE TO
NOSE SOUTHEAST ONTO THE PLAINS AND DRY AND VERY COLD WEATHER IS
FORECAST. TEMPS WILL CONTINUE TO STRUGGLE IN THE COLD AIRMASS AND
WILL GIVE TEMPS ABOUT A 10 DEGREE RISE FROM MORNING LOWS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 257 PM CST WED DEC 4 2013
THURSDAY NIGHT THROUGH WEDNESDAY. MAIN FORECAST
CONCERNS WILL BE CHANCE FOR SNOW SATURDAY NIGHT THROUGH SUNDAY NIGHT
AND COLD TEMPERATURES THROUGH THE PERIOD.
A COLD SURFACE HIGH PRESSURE SYSTEM WILL PUSH INTO THE AREA FOR
THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE CENTER OF THE HIGH WILL
REMAIN NORTH AND EAST OF THE AREA AND WINDS WILL CONTINUE TO BE
AROUND 5 TO 15 MPH. WITH THE TEMPERATURES ALREADY IN THE SINGLE
DIGITS ABOVE AND BELOW ZERO...THE WIND CHILL VALUES WILL DROP INTO
THE -10 TO -20 DEGREE RANGE ACROSS THE AREA.
ON SATURDAY THE SURFACE HIGH MOVES OFF TO THE EAST AND WINDS TURN TO
THE SOUTH. AN UPPER LEVEL WAVE APPROACHES THE AREA FROM THE
SOUTHWEST. THERE IS INCREASING MOISTURE ACROSS THE AREA AND CLOUDS
WILL INCREASE.
SATURDAY NIGHT THROUGH SUNDAY NIGHT THE UPPER LEVEL WAVE WILL MOVE
THROUGH THE REGION. STARTING SATURDAY NIGHT THERE IS WARM ADVECTION
OF MOIST AIR OVER THE COLD SURFACE. EXPECT SNOW TO START ACROSS THE
AREA DURING THE EVENING AND CONTINUE INTO SUNDAY. THE BEST CHANCES
WILL LIKELY BE LATE SATURDAY NIGHT INTO SUNDAY MORNING. MODELS HAVE
SOME VARIABLE QPF AMOUNTS BUT IT LOOKS LIKE THERE WILL BE
ACCUMULATING SNOWFALL. WITH THE COLD TEMPERATURES THERE WILL MOST
LIKELY BE LIGHT FLUFFY SNOWFALL. AN ADVANTAGE IS THAT CURRENTLY
THERE IS NOT SIGNIFICANT WIND WITH THE SYSTEM. BY SUNDAY EVENING THE
MAIN UPPER WAVE IS THROUGH THE AREA AND THE SNOWFALL WILL GRADUALLY
COME TO AN END SUNDAY NIGHT.
A COLD SURFACE HIGH PRESSURE SYSTEM MOVES INTO THE SOUTHERN PLAINS
ON MONDAY AND COLD TEMPERATURES WILL CONTINUE ACROSS THE AREA MONDAY
INTO TUESDAY. TUESDAY NIGHT ANOTHER WEAK UPPER LEVEL WAVE APPROACHES
THE AREA. THE MAIN WAVE IS FURTHER TO THE NORTH. MOST OF THE
MOISTURE IS FURTHER NORTH AND NOT MUCH CHANGE FROM MONDAY AND
TUESDAY. THE ONLY CHANGE WILL BE A POTENTIAL FOR SOME SLIGHTLY
WARMER TEMPERATURES.
&&
.AVIATION...(FOR THE 00Z KGRI TAF THROUGH 00Z THURSDAY EVENING)
ISSUED AT 557 PM CST WED DEC 4 2013
VFR CONDITIONS EXPECTED WITH A BRISK NORTHWEST WIND WITH MAINLY
MID-LEVEL CEILINGS TO CONTEND WITH. WIND SHOULD SLACK OFF SOME AS
THE PRESSURE GRADIENT DECREASES FOR THURSDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...FAY
LONG TERM...JCB
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1140 AM CST TUE DEC 3 2013
.UPDATE...
ISSUED AT 1034 AM CST TUE DEC 3 2013
LOTS OF STRATUS CONTINUES TO PUSH SOUTH ACROSS THE FORECAST AREA
THIS MORNING. WITH THIS STATUS MOVING IN...EXPECT TEMPERATURES TO
STRUGGLE TO CLIMB MUCH AFTER THE SKIES CLOUD OVER...AND
CORRESPONDINGLY DROPPED AFTERNOON FORECAST TEMPERATURES
SIGNIFICANTLY ACROSS THE ENTIRE AREA. STUCK FAIRLY CLOSE TO A
BLEND OF PREVIOUS FORECAST AND RAP MODEL...WHICH MAY ACTUALLY BE
TOO OPTIMISTIC FROM AROUND I80 SOUTH TO THE NE/KS STATE LINE...WHERE
STRATUS CONTINUES TO RAPIDLY ENCROACH A BIT FASTER THAN PREVIOUSLY
THOUGHT.
UPDATE ISSUED AT 628 AM CST TUE DEC 3 2013
SENT ANOTHER UPDATE TO LOWER HIGH TEMPS AND HOURLY TEMPS FURTHER
FROM LEXINGTON-ORD IN COORDINATION WITH LBF.
UPDATE ISSUED AT 603 AM CST TUE DEC 3 2013
WITH THE INITIAL FCST ISSUANCE AT 4 AM...WAS UNSURE WHY THE
00Z/06Z NAM TEMPS WERE FCST TO BEHAVE THE WAY THEY WERE DEPICTED
AND NOW IT IS CLEAR AS WE SEE STRATUS SURGING S ACROSS CNTRL NEB.
THE SKY FCST HAS BEEN ENHANCED BY USING THE 13 KM RAP WHICH HAS AN
EXCELLENT HANDLE ON THE STRATUS...EVEN DEPICTING ITS LEADING EDGE
ERODING AROUND MIDDAY. HAVE ALSO REPLACED THE PREVIOUS HIGH TEMP
FCST BY A 50-50 BLEND THE 00Z/06Z NAM 2M TEMPS. THIS HAS COOLED
FCST HIGHS ALONG THE I-80 CORRIDOR NORTHWARD.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CST TUE DEC 3 2013
...AN EXTENDED PERIOD OF HARSH WINTER COLD IS ON THE DOORSTEP AND
ONCE IT ARRIVES TONIGHT THERE ARE NO SIGNS OF IT RELEASING UNTIL
MID-MONTH APPROACHES...
ALOFT: THE COLD CORE ARCTIC LOW THAT WAS OVER SIBERIA 7 DAYS AGO
IS NOW ON OUR DOORSTEP /CURRENTLY OVER MT/. WESTERLY FLOW WILL
BECOME SW AS THE LOW BECOMES ELONGATED AND OPENS UP...EJECTING A
SHORTWAVE TROF ACROSS THE NRN PLAINS THIS AFTERNOON AND TONIGHT.
SFC: THE ARCTIC COLD FRONT WAS ALONG THE SD-NEB BORDER...WITH A
PRE-FRONTAL TROF EXTENDING E-W ACROSS NEB. BOTH OF THESE FEATURES
TO PRESS S...CROSSING THE FCST AREA BETWEEN 2 PM AND 8 PM.
BITTERLY COLD HIGH PRES OVER THE CANADIAN ROCKIES BEGINS BUILDING
IN TONIGHT. A LEE-SIDE LOW WILL MIGRATE DOWN THE FRONT RANGE
TODAY AND THEN EJECT ACROSS OK TONIGHT. THIS WILL MAINTAIN A
TIGHT PRES GRADIENT.
HI-RES MESOSCALE MODELS SUGGEST THE FOLLOWING APPROXIMATE TIMES
OF FRONTAL PASSAGE:
3 PM ORD-LEXINGTON
4 PM OSCEOLA-KEARNEY-ELWOOD
5 PM YORK-FRANKLIN-LONG ISLAND KS
6 PM GENEVA-SMITH CENTER KS-PHILLIPSBURG KS
7 PM MANKATO-OSBORNE-STOCKTON
8 PM BELOIT
EARLY THIS MORNING: A BATCH OF MULTI-LAYERED MID-HIGH CLOUDS WAS
MOVING THRU THE FCST AREA. CLOUD TOPS WERE WARMING. UEX/LNX
RADARS HAVE SHOWN SOME SMALL POCKETS OF PRECIP...BUT SUB-CLOUD
AIR IS TOO DRY FOR ANYTHING TO SURVIVE TO THE SURFACE.
TODAY: ONCE THE BATCH OF CLOUDS DEPARTS TO THE E...WE COULD SEE A
PERIOD OF SUBSTANTIAL SUNSHINE. LOOK FOR A RAPID WARM-UP. THIS
WILL BE THE LAST DAY OF MUCH WARMER THAN NORMAL TEMPS. HIGHS ARE
PRIMARILY BASED ON THE 21Z/2 BIAS CORRECTED SREF.
THE SATELLITE FOG/REFLECTIVITY PRODUCT SHOWS STRATUS OVERCAST
IMMEDIATELY BEHIND T HE FRONT. IT IS DISCONCERTING TO SEE IT
DROPPING INTO NRN NEB. THIS WILL NEED TO BE MONITORED AS
SUBSTANTIAL CHANGES WILL NEED TO OCCUR TO THE SHORT-TERM FCST.
THE 06Z NAM SUGGESTS THE STRATUS WILL DROP INTO AREAS N OF HWY
92...BUT THEN GET ERODED BY BOUNDARY LAYER MIXING.
POSSIBLE FCST SHORT-COMINGS: DO WE HAVE THE TIMING OF FRONTAL
PASSAGE CORRECT? THIS WILL HAVE SIGNIFICANT IMPLICATIONS ON THE
FCST. CONFIDENCE IN HOURLY TEMPS AND HIGHS ARE BELOW AVERAGE FROM
HWY 6 NORTHWARD.
IMMEDIATELY BEHIND THE FRONT EXPECT A RAPID INCREASE IN N WINDS
AND IT WILL CONTINUE THRU TONIGHT.
WIND: COOPERATIVE INSTITUTE FOR PRECIP SYSTEMS /CIPS/ TOP 10
ANALOGS OFFER A 50-60% CHANCE OF 30-35 KT WINDS. THE CHANCE FOR
36-40 KTS IS 30-40%. THE 00Z NAM HAS 30 KTS AS LOW AS 1000 FT AT
ORD WITH A MAX OF 32-34 KTS AVAILABLE AT THE TOP OF THE MIXED
LAYER. OVER THE REST OF S-CNTRL NEB 30 KTS IS FCST AS LOW AS 1500
FT WITH 32 KTS MAX. OVER N-CNTRL KS 30 KTS WILL BE AVAILABLE AT
THE TOP OF THE MIXED LAYER /2000 FT/. THIS MATCHES WELL WITH WHAT
IS OFFERED FROM THE CIPS ANALOGS. SO EXPECT THE HIGHEST GUSTS N OF
I-80...BUT THERE IS POTENTIAL FOR EVERYWHERE TO GUST TO 30 KTS
WITH THE HIGHEST PROBABILITY OVER S-CNTRL NEB. 06Z NAM CHECKED. IT
LOOKS A BIT MORE THREATENING WITH MAX GUSTS UP TO 35 KTS N OF HWY
6.
TONIGHT: CLOUDY WITH HARSH N WINDS. LOW TEMPS NEAR NORMAL.
AS FOR PRECIP TODAY-TONIGHT...A SHALLOW FRONTOGENETIC CIRCULATION
WILL NOT BE AIDED BY ANY DEEP-LAYER FORCING/LIFT. AND WHILE THE
LOW-LEVELS AND MID-LEVELS ABOVE 12K FT WILL BE AT OR NEAR
SATURATION ...THE 7-11K FT LAYER WILL BE DRY. SO PLAYED IT AS A
SLIGHT CHANCE FOR A LITTLE LIGHT RAIN/SNOW N OF HWY 92 LATE THIS
AFTERNOON AND A SLIGHT CHANCE OF LIGHT SNOW TONIGHT. BY 09Z...THE
BASE OF THE STRATUS WILL BECOME COLD ENOUGH FOR ICE TO FORM IN-
CLOUD. SO A SLIGHT CHANCE OF FLURRIES WAS INCLUDED FROM HWY 92
DOWN TO HWY 6 LATE TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM CST TUE DEC 3 2013
GUIDANCE SUGGESTS A MID TO UPPER LEVEL LONG WAVE TROUGH WILL
EXTEND FROM CENTRAL CANADA...SOUTHWEST INTO THE WESTERN CONUS AT
12Z WEDNESDAY. THIS LONG WAVE TROUGH IS EXPECTED TO PERSIST OVER
THE SAME AREAS THROUGH 12Z FRIDAY...AT WHICH TIME IT SHOULD MOVE
EAST/NORTHEAST AND WEAKEN. A SECOND MID TO UPPER LEVEL LONGWAVE
TROUGH IS THEN EXPECTED TO DEVELOP OVER THE WESTERN CONUS SATURDAY
INTO SATURDAY NIGHT AND PERSIST THROUGH THE END OF THE LONG TERM
FORECAST PERIOD. RESULTANT MID TO UPPER LEVEL FLOW OVER OUR AREA
IS EXPECTED TO REMAIN FROM THE SOUTHWEST 12Z WEDNESDAY THROUGH 12Z
FRIDAY...WITH QUASI-ZONAL FLOW EXPECTED FRIDAY INTO FRIDAY
NIGHT...AND SOUTHWEST FLOW ONCE AGAIN SATURDAY THROUGH THE END OF
THE LONG TERM FORECAST PERIOD. A CLOSED MID LEVEL LOW...EMBEDDED
WITHIN THE FIRST LONG WAVE TROUGH...IS EXPECTED OVER THE NORTHERN
PLAINS AT 12Z WEDNESDAY...WITH THIS MID LEVEL LOW EXPECTED TO
EJECT TO THE NORTHEAST...AWAY FROM THE LONG WAVE TROUGH...INTO
ONTARIO AND QUEBEC BETWEEN 12Z WEDNESDAY AND 12Z FRIDAY. A
SECONDARY MID LEVEL LOW IS ALSO EXPECTED TO MOVE SOUTH AND THEN
EAST FROM SASKATCHEWAN INTO THE NORTHERN PLAINS BETWEEN 12Z
WEDNESDAY AND 12Z FRIDAY. THIS SECONDARY MID LEVEL LOW IS THEN
EXPECTED TO MOVE EAST/NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY
AND ONTARIO...ALONG WITH THE LONG WAVE TROUGH...FRIDAY INTO FRIDAY
NIGHT. THERE ARE THEN INDICATIONS OF A MID LEVEL SHORTWAVE
EJECTING FROM THE WESTERN CONUS AND MOVING EAST ACROSS PORTIONS OF
THE CENTRAL AND SOUTHERN PLAINS ON SUNDAY. AT THE SURFACE AN AREA
LOW BAROMETRIC PRESSURE IS EXPECTED OVER THE UPPER MISSISSIPPI
VALLEY AT 12Z WEDNESDAY...WITH AN ASSOCIATED LOW LEVEL BAROCLINIC
ZONE EXTENDING SOUTH/SOUTHWEST FROM THE LOW INTO THE MID
MISSISSIPPI VALLEY AND SOUTHERN PLAINS. STRONG SURFACE RIDGING
SHOULD BE WORKING INTO THE CENTRAL PLAINS ON WEDNESDAY AS THE
FIRST MID LEVEL LOW AND SURFACE LOW DEPART TO THE NORTHEAST. THE
SURFACE RIDGE SHOULD THEN PERSIST ACROSS THE CENTRAL PLAINS
THROUGH FRIDAY AS THE SECONDARY MID LEVEL LOW ADVANCES SOUTH AND
THEN EAST FROM SASKATCHEWAN...INDUCING A WEAK AREA OF LOW
BAROMETRIC PRESSURE AT THE SURFACE ACROSS PORTIONS OF THE UPPER
MISSISSIPPI VALLEY. LEE SIDE TROUGHING ALONG THE FRONT RANGE IS
THEN EXPECTED TO DEVELOP FRIDAY NIGHT INTO SATURDAY.
FINALLY...THERE IS A LIKELIHOOD A SURFACE LOW WILL MOVE EAST
SOMEWHERE ACROSS THE CENTRAL AND/OR SOUTHERN PLAINS DURING THE DAY
SUNDAY AS THE MID LEVEL SHORTWAVE DOES THE SAME. GIVEN ALL
THIS...LOW LEVEL FLOW SHOULD REMAIN FROM THE NORTH/NORTHWEST
WEDNESDAY FRIDAY...WITH SOUTHERLY FLOW EXPECTED SATURDAY...AND
ANOTHER ROUND OF NORTHWESTERLY LOW LEVEL FLOW TOWARDS THE END OF
THE FORECAST PERIOD.
ALTHOUGH THERE COULD BE A WEAK RIBBON OF MID LEVEL THERMAL
ADVECTION GRAZING OUR NORTHWEST DURING THE DAY WEDNESDAY...AT THIS
TIME IT APPEARS ANY SUBSTANTIAL OMEGA WILL REMAIN RELEGATED
NORTH/NORTHEAST AND WEST OF OUR AREA...EITHER IN CLOSER PROXIMITY
TO THE DEPARTING MID LEVEL LOW TO OUR NORTH/NORTHEAST OR IN CLOSER
PROXIMITY TO THE LONGWAVE TROUGH AXIS TO OUR WEST. WENT AHEAD WITH
DRY CONDITIONS ON WEDNESDAY AS A RESULT. HEADING INTO WEDNESDAY
NIGHT...THERE ARE INDICATIONS OF A ~90KT MID LEVEL JET STREAK
MOVING INTO THE MID MISSISSIPPI VALLEY...WITH THE RIGHT-REAR
QUADRANT OF THIS STREAK PERHAPS GENERATING ENOUGH OF A DIRECT
THERMAL CIRCULATION AND RESULTANT OMEGA FOR PRECIPITATION
PRODUCTION ACROSS PORTIONS OF OUR CWA. QPF FIELDS FROM THE
NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL SEEM TO SUGGEST OUR
WEST/SOUTHWEST CWA STAND THE BEST CHANCE AT OBSERVING MEASURABLE
PRECIPITATION. AS A RESULT...WENT AHEAD WITH ~20% POPS ACROSS OUR
WEST/SOUTHWEST 00Z-06Z THURSDAY. IT APPEARS THE MID LEVEL JET
STREAK WILL PERSIST THURSDAY INTO THURSDAY NIGHT AS WELL...HOWEVER
IT ALSO APPEARS THE JET STREAK AXIS WILL SHIFT EAST/SOUTHEAST
SOMEWHAT...THUS POSITIONING THE RIGHT-REAR QUADRANT AND RESULTANT
OMEGA SLIGHTLY SOUTH/SOUTHEAST OF OUR AREA AS WELL. ALTHOUGH SOME
GUIDANCE SUGGESTS OUR EXTREME SOUTH COULD OBSERVE MEASURABLE
PRECIPITATION AT ONE TIME OR ANOTHER THURSDAY AND THURSDAY
NIGHT...THERE REALLY IS NO AGREEMENT BETWEEN THE MODELS AS TO
WHETHER THIS WILL OCCUR THURSDAY...THURSDAY NIGHT...OR AT ALL.
ALTHOUGH WE PROBABLY CANNOT COMPLETELY RULE OUT A PERIOD OF VERY
LIGHT PRECIPITATION AT SOME POINT DURING THE THURSDAY-THURSDAY
NIGHT TIME PERIOD...GIVEN THE PRIMARY AXIS OF OMEGA APPEARS TO
REMAIN SOUTH/SOUTHEAST OF OUR AREA AND THE VERY LOW CONFIDENCE
THAT ANYONE WOULD ACTUALLY OBSERVE MEASURABLE
PRECIPITATION...OPTED TO REMOVE MEASURABLE PRECIPITATION FROM THE
THURSDAY-THURSDAY NIGHT TIME PERIOD AND INSTEAD GO AHEAD WITH A
MENTION OF SNOW FLURRIES. THE APPROACH OF THE MID LEVEL SHORTWAVE
SUNDAY COULD THEN BRING A CHANCE FOR PRECIPITATION SUNDAY.
ALLBLEND RESPONDED BY PROVIDING ~30% POPS TO THE AREA AND THESE
POPS WERE LEFT UNCHANGED FOR THE MOST PART.
FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE NAM
AND OPERATIONAL GFS...SUGGEST AN INVASION OF ARCTIC AIR WILL KEEP
THE LOWER TROPOSPHERE COLD ENOUGH FOR SNOW PRODUCTION DURING THE
LONG TERM FORECAST PERIOD. ANY SNOWFALL THAT IS REALIZED ACROSS
OUR CWA WEDNESDAY NIGHT INTO THURSDAY SHOULD REMAIN VERY LIGHT.
THAT BEING SAID...THE VERY COLD/DRY LOWER TROPOSPHERE SUGGESTS
SNOW-WATER RATIOS WILL BE VERY HIGH...SOMEWHERE IN 20-30:1
RANGE...THUS EVEN A COUPLE HUNDREDTHS OF AN INCH OF LIQUID
PRECIPITATION...WHICH IS FORECAST ACROSS OUR WEST/SOUTHWEST 00-06Z
THURSDAY...COULD BE CAPABLE OF PRODUCING ~0.5" OF SNOWFALL. THE
MID LEVEL SHORTWAVE WHICH COULD POTENTIALLY IMPACT OUR AREA NEXT
SUNDAY IS SLIGHTLY MORE INTERESTING...WITH THE OPERATIONAL GFS AND
EC BOTH SUGGESTING SNOWFALL ACCUMULATION IN EXCESS OF AN INCH WILL
BE REALIZED ACROSS THE CWA. CERTAINLY SOMETHING TO CONTINUE
MONITORING.
ARCTIC AIR REMAINS POISED TO OCCUPY THE CENTRAL PLAINS DURING THE
LONG TERM FORECAST PERIOD. TEMPERATURES WITHIN THE SOURCE REGION
OF THE ARCTIC AIRMASS...CURRENTLY ACROSS PORTIONS OF
ALBERTA...SASKATCHEWAN AND MANITOBA...ONLY CLIMBED INTO THE TEENS
AND 20S MONDAY AFTERNOON...AND THESE VALUES ARE ALSO BEING
PRESENTED TO OUR AREA BY MULTIPLE SETS OF GUIDANCE THURSDAY
ONWARD. WEDNESDAY MAY ACTUALLY BE A TOUCH WARMER AS THE TRUE MASS
OF ARCTIC AIR WILL TAKE SOME TIME TO WORK INTO THE REGION...THUS
WEDNESDAY AFTERNOON HIGHS RANGING FROM THE 20S TO NEAR 30 ARE
FORECAST. BASED ON THE SOURCE REGION OF THE INCOMING ARCTIC AIR
MASS...IT APPEARS LIKELY OVERNIGHT LOWS IN THE SINGLE DIGITS WILL
ALSO BE COMMON THURSDAY ONWARD.
FINALLY...LATEST GUIDANCE SUGGESTS A SUSTAINED LOW LEVEL WIND
FIELD AT AROUND 15KTS...WORKING IN CONCERT WITH THE AFOREMENTIONED
SINGLE DIGIT OVERNIGHT LOWS...WILL PROVIDE APPARENT TEMPERATURE
VALUES BETWEEN -15 AND -19 DEGREES F ACROSS NORTHWESTERN PORTIONS
OF OUR CWA WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. WILL GO
AHEAD AND OUTLOOK THESE CONDITIONS IN THE HWO...PRIMARILY FOR
LOCATIONS ALONG AND NORTHWEST OF A LINE OF LEXINGTON...TO LOUP
CITY AND GREELEY. ALTHOUGH THESE VALUES DO NOT JUSTIFY ADVISORY
ISSUANCE...THIS WILL CERTAINLY NEED TO BE MONITORED THROUGH THE
NEXT COUPLE DAYS IN CASE HEADLINES BECOME NECESSARY. ALTHOUGH NOT
AS WIDESPREAD...APPARENT TEMPERATURE VALUES ARE ALSO FORECAST TO
APPROACH -15 DEGREES F ACROSS VALLEY AND GREELEY COUNTIES EARLY
FRIDAY MORNING AS WELL.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z WEDNESDAY
AFTERNOON) ISSUED AT 1135 AM CST TUE DEC 3 2013
IFR STRATUS AND NEAR MVFR VSBYS WILL CONTINUE AT THE TERMINAL
THROUGH THE AFTERNOON HOURS AS PLENTY OF STRATUS CONTINUES TO
STREAM IN FROM THE NORTH. WINDS WILL INCREASE SIGNIFICANTLY DURING
THE EVENING HOURS AS THE MAIN COLD FRONT PUSHES ACROSS THE
TERMINAL...AND THEN REMAIN ELEVATED...GUSTING TO 30 KTS OR
HIGHER...THROUGH THE AFTERNOON HOURS WEDNESDAY. MAY SEE SOME LIGHT
SNOW AT THE TERMINAL OVERNIGHT...BUT CONFIDENCE WAS LOW ENOUGH TO
LEAVE OUT OF THE TAF FOR THE TIME BEING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...ROSSI
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1038 AM CST TUE DEC 3 2013
.UPDATE...
ISSUED AT 1034 AM CST TUE DEC 3 2013
LOTS OF STRATUS CONTINUES TO PUSH SOUTH ACROSS THE FORECAST AREA
THIS MORNING. WITH THIS STATUS MOVING IN...EXPECT TEMPERATURES TO
STRUGGLE TO CLIMB MUCH AFTER THE SKIES CLOUD OVER...AND
CORRESPONDINGLY DROPPED AFTERNOON FORECAST TEMPERATURES
SIGNIFICANTLY ACROSS THE ENTIRE AREA. STUCK FAIRLY CLOSE TO A
BLEND OF PREVIOUS FORECAST AND RAP MODEL...WHICH MAY ACTUALLY BE
TOO OPTIMISTIC FROM AROUND I80 SOUTH TO THE NE/KS STATE LINE...WHERE
STRATUS CONTINUES TO RAPIDLY ENCROACH A BIT FASTER THAN PREVIOUSLY
THOUGHT.
UPDATE ISSUED AT 628 AM CST TUE DEC 3 2013
SENT ANOTHER UPDATE TO LOWER HIGH TEMPS AND HOURLY TEMPS FURTHER
FROM LEXINGTON-ORD IN COORDINATION WITH LBF.
UPDATE ISSUED AT 603 AM CST TUE DEC 3 2013
WITH THE INITIAL FCST ISSUANCE AT 4 AM...WAS UNSURE WHY THE
00Z/06Z NAM TEMPS WERE FCST TO BEHAVE THE WAY THEY WERE DEPICTED
AND NOW IT IS CLEAR AS WE SEE STRATUS SURGING S ACROSS CNTRL NEB.
THE SKY FCST HAS BEEN ENHANCED BY USING THE 13 KM RAP WHICH HAS AN
EXCELLENT HANDLE ON THE STRATUS...EVEN DEPICTING ITS LEADING EDGE
ERODING AROUND MIDDAY. HAVE ALSO REPLACED THE PREVIOUS HIGH TEMP
FCST BY A 50-50 BLEND THE 00Z/06Z NAM 2M TEMPS. THIS HAS COOLED
FCST HIGHS ALONG THE I-80 CORRIDOR NORTHWARD.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CST TUE DEC 3 2013
...AN EXTENDED PERIOD OF HARSH WINTER COLD IS ON THE DOORSTEP AND
ONCE IT ARRIVES TONIGHT THERE ARE NO SIGNS OF IT RELEASING UNTIL
MID-MONTH APPROACHES...
ALOFT: THE COLD CORE ARCTIC LOW THAT WAS OVER SIBERIA 7 DAYS AGO
IS NOW ON OUR DOORSTEP /CURRENTLY OVER MT/. WESTERLY FLOW WILL
BECOME SW AS THE LOW BECOMES ELONGATED AND OPENS UP...EJECTING A
SHORTWAVE TROF ACROSS THE NRN PLAINS THIS AFTERNOON AND TONIGHT.
SFC: THE ARCTIC COLD FRONT WAS ALONG THE SD-NEB BORDER...WITH A
PRE-FRONTAL TROF EXTENDING E-W ACROSS NEB. BOTH OF THESE FEATURES
TO PRESS S...CROSSING THE FCST AREA BETWEEN 2 PM AND 8 PM.
BITTERLY COLD HIGH PRES OVER THE CANADIAN ROCKIES BEGINS BUILDING
IN TONIGHT. A LEE-SIDE LOW WILL MIGRATE DOWN THE FRONT RANGE
TODAY AND THEN EJECT ACROSS OK TONIGHT. THIS WILL MAINTAIN A
TIGHT PRES GRADIENT.
HI-RES MESOSCALE MODELS SUGGEST THE FOLLOWING APPROXIMATE TIMES
OF FRONTAL PASSAGE:
3 PM ORD-LEXINGTON
4 PM OSCEOLA-KEARNEY-ELWOOD
5 PM YORK-FRANKLIN-LONG ISLAND KS
6 PM GENEVA-SMITH CENTER KS-PHILLIPSBURG KS
7 PM MANKATO-OSBORNE-STOCKTON
8 PM BELOIT
EARLY THIS MORNING: A BATCH OF MULTI-LAYERED MID-HIGH CLOUDS WAS
MOVING THRU THE FCST AREA. CLOUD TOPS WERE WARMING. UEX/LNX
RADARS HAVE SHOWN SOME SMALL POCKETS OF PRECIP...BUT SUB-CLOUD
AIR IS TOO DRY FOR ANYTHING TO SURVIVE TO THE SURFACE.
TODAY: ONCE THE BATCH OF CLOUDS DEPARTS TO THE E...WE COULD SEE A
PERIOD OF SUBSTANTIAL SUNSHINE. LOOK FOR A RAPID WARM-UP. THIS
WILL BE THE LAST DAY OF MUCH WARMER THAN NORMAL TEMPS. HIGHS ARE
PRIMARILY BASED ON THE 21Z/2 BIAS CORRECTED SREF.
THE SATELLITE FOG/REFLECTIVITY PRODUCT SHOWS STRATUS OVERCAST
IMMEDIATELY BEHIND T HE FRONT. IT IS DISCONCERTING TO SEE IT
DROPPING INTO NRN NEB. THIS WILL NEED TO BE MONITORED AS
SUBSTANTIAL CHANGES WILL NEED TO OCCUR TO THE SHORT-TERM FCST.
THE 06Z NAM SUGGESTS THE STRATUS WILL DROP INTO AREAS N OF HWY
92...BUT THEN GET ERODED BY BOUNDARY LAYER MIXING.
POSSIBLE FCST SHORT-COMINGS: DO WE HAVE THE TIMING OF FRONTAL
PASSAGE CORRECT? THIS WILL HAVE SIGNIFICANT IMPLICATIONS ON THE
FCST. CONFIDENCE IN HOURLY TEMPS AND HIGHS ARE BELOW AVERAGE FROM
HWY 6 NORTHWARD.
IMMEDIATELY BEHIND THE FRONT EXPECT A RAPID INCREASE IN N WINDS
AND IT WILL CONTINUE THRU TONIGHT.
WIND: COOPERATIVE INSTITUTE FOR PRECIP SYSTEMS /CIPS/ TOP 10
ANALOGS OFFER A 50-60% CHANCE OF 30-35 KT WINDS. THE CHANCE FOR
36-40 KTS IS 30-40%. THE 00Z NAM HAS 30 KTS AS LOW AS 1000 FT AT
ORD WITH A MAX OF 32-34 KTS AVAILABLE AT THE TOP OF THE MIXED
LAYER. OVER THE REST OF S-CNTRL NEB 30 KTS IS FCST AS LOW AS 1500
FT WITH 32 KTS MAX. OVER N-CNTRL KS 30 KTS WILL BE AVAILABLE AT
THE TOP OF THE MIXED LAYER /2000 FT/. THIS MATCHES WELL WITH WHAT
IS OFFERED FROM THE CIPS ANALOGS. SO EXPECT THE HIGHEST GUSTS N OF
I-80...BUT THERE IS POTENTIAL FOR EVERYWHERE TO GUST TO 30 KTS
WITH THE HIGHEST PROBABILITY OVER S-CNTRL NEB. 06Z NAM CHECKED. IT
LOOKS A BIT MORE THREATENING WITH MAX GUSTS UP TO 35 KTS N OF HWY
6.
TONIGHT: CLOUDY WITH HARSH N WINDS. LOW TEMPS NEAR NORMAL.
AS FOR PRECIP TODAY-TONIGHT...A SHALLOW FRONTOGENETIC CIRCULATION
WILL NOT BE AIDED BY ANY DEEP-LAYER FORCING/LIFT. AND WHILE THE
LOW-LEVELS AND MID-LEVELS ABOVE 12K FT WILL BE AT OR NEAR
SATURATION ...THE 7-11K FT LAYER WILL BE DRY. SO PLAYED IT AS A
SLIGHT CHANCE FOR A LITTLE LIGHT RAIN/SNOW N OF HWY 92 LATE THIS
AFTERNOON AND A SLIGHT CHANCE OF LIGHT SNOW TONIGHT. BY 09Z...THE
BASE OF THE STRATUS WILL BECOME COLD ENOUGH FOR ICE TO FORM IN-
CLOUD. SO A SLIGHT CHANCE OF FLURRIES WAS INCLUDED FROM HWY 92
DOWN TO HWY 6 LATE TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM CST TUE DEC 3 2013
GUIDANCE SUGGESTS A MID TO UPPER LEVEL LONG WAVE TROUGH WILL
EXTEND FROM CENTRAL CANADA...SOUTHWEST INTO THE WESTERN CONUS AT
12Z WEDNESDAY. THIS LONG WAVE TROUGH IS EXPECTED TO PERSIST OVER
THE SAME AREAS THROUGH 12Z FRIDAY...AT WHICH TIME IT SHOULD MOVE
EAST/NORTHEAST AND WEAKEN. A SECOND MID TO UPPER LEVEL LONGWAVE
TROUGH IS THEN EXPECTED TO DEVELOP OVER THE WESTERN CONUS SATURDAY
INTO SATURDAY NIGHT AND PERSIST THROUGH THE END OF THE LONG TERM
FORECAST PERIOD. RESULTANT MID TO UPPER LEVEL FLOW OVER OUR AREA
IS EXPECTED TO REMAIN FROM THE SOUTHWEST 12Z WEDNESDAY THROUGH 12Z
FRIDAY...WITH QUASI-ZONAL FLOW EXPECTED FRIDAY INTO FRIDAY
NIGHT...AND SOUTHWEST FLOW ONCE AGAIN SATURDAY THROUGH THE END OF
THE LONG TERM FORECAST PERIOD. A CLOSED MID LEVEL LOW...EMBEDDED
WITHIN THE FIRST LONG WAVE TROUGH...IS EXPECTED OVER THE NORTHERN
PLAINS AT 12Z WEDNESDAY...WITH THIS MID LEVEL LOW EXPECTED TO
EJECT TO THE NORTHEAST...AWAY FROM THE LONG WAVE TROUGH...INTO
ONTARIO AND QUEBEC BETWEEN 12Z WEDNESDAY AND 12Z FRIDAY. A
SECONDARY MID LEVEL LOW IS ALSO EXPECTED TO MOVE SOUTH AND THEN
EAST FROM SASKATCHEWAN INTO THE NORTHERN PLAINS BETWEEN 12Z
WEDNESDAY AND 12Z FRIDAY. THIS SECONDARY MID LEVEL LOW IS THEN
EXPECTED TO MOVE EAST/NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY
AND ONTARIO...ALONG WITH THE LONG WAVE TROUGH...FRIDAY INTO FRIDAY
NIGHT. THERE ARE THEN INDICATIONS OF A MID LEVEL SHORTWAVE
EJECTING FROM THE WESTERN CONUS AND MOVING EAST ACROSS PORTIONS OF
THE CENTRAL AND SOUTHERN PLAINS ON SUNDAY. AT THE SURFACE AN AREA
LOW BAROMETRIC PRESSURE IS EXPECTED OVER THE UPPER MISSISSIPPI
VALLEY AT 12Z WEDNESDAY...WITH AN ASSOCIATED LOW LEVEL BAROCLINIC
ZONE EXTENDING SOUTH/SOUTHWEST FROM THE LOW INTO THE MID
MISSISSIPPI VALLEY AND SOUTHERN PLAINS. STRONG SURFACE RIDGING
SHOULD BE WORKING INTO THE CENTRAL PLAINS ON WEDNESDAY AS THE
FIRST MID LEVEL LOW AND SURFACE LOW DEPART TO THE NORTHEAST. THE
SURFACE RIDGE SHOULD THEN PERSIST ACROSS THE CENTRAL PLAINS
THROUGH FRIDAY AS THE SECONDARY MID LEVEL LOW ADVANCES SOUTH AND
THEN EAST FROM SASKATCHEWAN...INDUCING A WEAK AREA OF LOW
BAROMETRIC PRESSURE AT THE SURFACE ACROSS PORTIONS OF THE UPPER
MISSISSIPPI VALLEY. LEE SIDE TROUGHING ALONG THE FRONT RANGE IS
THEN EXPECTED TO DEVELOP FRIDAY NIGHT INTO SATURDAY.
FINALLY...THERE IS A LIKELIHOOD A SURFACE LOW WILL MOVE EAST
SOMEWHERE ACROSS THE CENTRAL AND/OR SOUTHERN PLAINS DURING THE DAY
SUNDAY AS THE MID LEVEL SHORTWAVE DOES THE SAME. GIVEN ALL
THIS...LOW LEVEL FLOW SHOULD REMAIN FROM THE NORTH/NORTHWEST
WEDNESDAY FRIDAY...WITH SOUTHERLY FLOW EXPECTED SATURDAY...AND
ANOTHER ROUND OF NORTHWESTERLY LOW LEVEL FLOW TOWARDS THE END OF
THE FORECAST PERIOD.
ALTHOUGH THERE COULD BE A WEAK RIBBON OF MID LEVEL THERMAL
ADVECTION GRAZING OUR NORTHWEST DURING THE DAY WEDNESDAY...AT THIS
TIME IT APPEARS ANY SUBSTANTIAL OMEGA WILL REMAIN RELEGATED
NORTH/NORTHEAST AND WEST OF OUR AREA...EITHER IN CLOSER PROXIMITY
TO THE DEPARTING MID LEVEL LOW TO OUR NORTH/NORTHEAST OR IN CLOSER
PROXIMITY TO THE LONGWAVE TROUGH AXIS TO OUR WEST. WENT AHEAD WITH
DRY CONDITIONS ON WEDNESDAY AS A RESULT. HEADING INTO WEDNESDAY
NIGHT...THERE ARE INDICATIONS OF A ~90KT MID LEVEL JET STREAK
MOVING INTO THE MID MISSISSIPPI VALLEY...WITH THE RIGHT-REAR
QUADRANT OF THIS STREAK PERHAPS GENERATING ENOUGH OF A DIRECT
THERMAL CIRCULATION AND RESULTANT OMEGA FOR PRECIPITATION
PRODUCTION ACROSS PORTIONS OF OUR CWA. QPF FIELDS FROM THE
NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL SEEM TO SUGGEST OUR
WEST/SOUTHWEST CWA STAND THE BEST CHANCE AT OBSERVING MEASURABLE
PRECIPITATION. AS A RESULT...WENT AHEAD WITH ~20% POPS ACROSS OUR
WEST/SOUTHWEST 00Z-06Z THURSDAY. IT APPEARS THE MID LEVEL JET
STREAK WILL PERSIST THURSDAY INTO THURSDAY NIGHT AS WELL...HOWEVER
IT ALSO APPEARS THE JET STREAK AXIS WILL SHIFT EAST/SOUTHEAST
SOMEWHAT...THUS POSITIONING THE RIGHT-REAR QUADRANT AND RESULTANT
OMEGA SLIGHTLY SOUTH/SOUTHEAST OF OUR AREA AS WELL. ALTHOUGH SOME
GUIDANCE SUGGESTS OUR EXTREME SOUTH COULD OBSERVE MEASURABLE
PRECIPITATION AT ONE TIME OR ANOTHER THURSDAY AND THURSDAY
NIGHT...THERE REALLY IS NO AGREEMENT BETWEEN THE MODELS AS TO
WHETHER THIS WILL OCCUR THURSDAY...THURSDAY NIGHT...OR AT ALL.
ALTHOUGH WE PROBABLY CANNOT COMPLETELY RULE OUT A PERIOD OF VERY
LIGHT PRECIPITATION AT SOME POINT DURING THE THURSDAY-THURSDAY
NIGHT TIME PERIOD...GIVEN THE PRIMARY AXIS OF OMEGA APPEARS TO
REMAIN SOUTH/SOUTHEAST OF OUR AREA AND THE VERY LOW CONFIDENCE
THAT ANYONE WOULD ACTUALLY OBSERVE MEASURABLE
PRECIPITATION...OPTED TO REMOVE MEASURABLE PRECIPITATION FROM THE
THURSDAY-THURSDAY NIGHT TIME PERIOD AND INSTEAD GO AHEAD WITH A
MENTION OF SNOW FLURRIES. THE APPROACH OF THE MID LEVEL SHORTWAVE
SUNDAY COULD THEN BRING A CHANCE FOR PRECIPITATION SUNDAY.
ALLBLEND RESPONDED BY PROVIDING ~30% POPS TO THE AREA AND THESE
POPS WERE LEFT UNCHANGED FOR THE MOST PART.
FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE NAM
AND OPERATIONAL GFS...SUGGEST AN INVASION OF ARCTIC AIR WILL KEEP
THE LOWER TROPOSPHERE COLD ENOUGH FOR SNOW PRODUCTION DURING THE
LONG TERM FORECAST PERIOD. ANY SNOWFALL THAT IS REALIZED ACROSS
OUR CWA WEDNESDAY NIGHT INTO THURSDAY SHOULD REMAIN VERY LIGHT.
THAT BEING SAID...THE VERY COLD/DRY LOWER TROPOSPHERE SUGGESTS
SNOW-WATER RATIOS WILL BE VERY HIGH...SOMEWHERE IN 20-30:1
RANGE...THUS EVEN A COUPLE HUNDREDTHS OF AN INCH OF LIQUID
PRECIPITATION...WHICH IS FORECAST ACROSS OUR WEST/SOUTHWEST 00-06Z
THURSDAY...COULD BE CAPABLE OF PRODUCING ~0.5" OF SNOWFALL. THE
MID LEVEL SHORTWAVE WHICH COULD POTENTIALLY IMPACT OUR AREA NEXT
SUNDAY IS SLIGHTLY MORE INTERESTING...WITH THE OPERATIONAL GFS AND
EC BOTH SUGGESTING SNOWFALL ACCUMULATION IN EXCESS OF AN INCH WILL
BE REALIZED ACROSS THE CWA. CERTAINLY SOMETHING TO CONTINUE
MONITORING.
ARCTIC AIR REMAINS POISED TO OCCUPY THE CENTRAL PLAINS DURING THE
LONG TERM FORECAST PERIOD. TEMPERATURES WITHIN THE SOURCE REGION
OF THE ARCTIC AIRMASS...CURRENTLY ACROSS PORTIONS OF
ALBERTA...SASKATCHEWAN AND MANITOBA...ONLY CLIMBED INTO THE TEENS
AND 20S MONDAY AFTERNOON...AND THESE VALUES ARE ALSO BEING
PRESENTED TO OUR AREA BY MULTIPLE SETS OF GUIDANCE THURSDAY
ONWARD. WEDNESDAY MAY ACTUALLY BE A TOUCH WARMER AS THE TRUE MASS
OF ARCTIC AIR WILL TAKE SOME TIME TO WORK INTO THE REGION...THUS
WEDNESDAY AFTERNOON HIGHS RANGING FROM THE 20S TO NEAR 30 ARE
FORECAST. BASED ON THE SOURCE REGION OF THE INCOMING ARCTIC AIR
MASS...IT APPEARS LIKELY OVERNIGHT LOWS IN THE SINGLE DIGITS WILL
ALSO BE COMMON THURSDAY ONWARD.
FINALLY...LATEST GUIDANCE SUGGESTS A SUSTAINED LOW LEVEL WIND
FIELD AT AROUND 15KTS...WORKING IN CONCERT WITH THE AFOREMENTIONED
SINGLE DIGIT OVERNIGHT LOWS...WILL PROVIDE APPARENT TEMPERATURE
VALUES BETWEEN -15 AND -19 DEGREES F ACROSS NORTHWESTERN PORTIONS
OF OUR CWA WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. WILL GO
AHEAD AND OUTLOOK THESE CONDITIONS IN THE HWO...PRIMARILY FOR
LOCATIONS ALONG AND NORTHWEST OF A LINE OF LEXINGTON...TO LOUP
CITY AND GREELEY. ALTHOUGH THESE VALUES DO NOT JUSTIFY ADVISORY
ISSUANCE...THIS WILL CERTAINLY NEED TO BE MONITORED THROUGH THE
NEXT COUPLE DAYS IN CASE HEADLINES BECOME NECESSARY. ALTHOUGH NOT
AS WIDESPREAD...APPARENT TEMPERATURE VALUES ARE ALSO FORECAST TO
APPROACH -15 DEGREES F ACROSS VALLEY AND GREELEY COUNTIES EARLY
FRIDAY MORNING AS WELL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 603 AM CST TUE DEC 3 2013
TODAY: FOG/REFLECTIVITY SATELLITE IMAGERY SHOWS IFR STRATUS IS
SURGING S TOWARD GRI AT 12Z. ODX IS NOW OVC008 AND HAVE TIMED
THIS INTO GRI AT 14Z. THE STATISTICAL MODEL OUTPUT IS NOT HANDLING
THIS STRATUS. SO THIS FCST IS BASED ON CURRENT TRENDS AND MODEL RH
FIELDS...WHICH INDICATE THE LEADING EDGE OF THE STRATUS COULD
BEGIN ERODING AROUND MIDDAY...ALLOWING FOR A COUPLE HRS OF VFR
CIGS. IF THIS OCCURS...STRATUS WILL RE-INVADE AROUND 21Z WITH
FRONTAL PASSAGE. SHOULD SEE A SIGNIFICANT INCREASE IN N WINDS...
BUT THERE IS UNCERTAINTY ON IF ITS GRADUAL OR ABRUPT. CONFIDENCE:
AVERAGE
TONIGHT: STATISTICAL MODEL OUTPUT SUGGESTS MVFR CIGS...BUT CURRENT
OBS UPSTREAM ARE LARGELY IFR. THE TAF CIG IS MORE PESSIMISTIC THAN
MOS BUT NOT AS PESSIMISTIC AS CURRENT OBS UPSTREAM. BE AWARE THAT
CIGS MAY NEED TO BE DOWNGRADED A CATEGORY LATER TODAY. CONFIDENCE:
AVERAGE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...ROSSI
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
628 AM CST TUE DEC 3 2013
.UPDATE...
ISSUED AT 628 AM CST TUE DEC 3 2013
SENT ANOTHER UPDATE TO LOWER HIGH TEMPS AND HOURLY TEMPS FURTHER
FROM LEXINGTON-ORD IN COORDINATION WITH LBF.
UPDATE ISSUED AT 603 AM CST TUE DEC 3 2013
WITH THE INITIAL FCST ISSUANCE AT 4 AM...WAS UNSURE WHY THE
00Z/06Z NAM TEMPS WERE FCST TO BEHAVE THE WAY THEY WERE DEPICTED
AND NOW IT IS CLEAR AS WE SEE STRATUS SURGING S ACROSS CNTRL NEB.
THE SKY FCST HAS BEEN ENHANCED BY USING THE 13 KM RAP WHICH HAS AN
EXCELLENT HANDLE ON THE STRATUS...EVEN DEPICTING ITS LEADING EDGE
ERODING AROUND MIDDAY. HAVE ALSO REPLACED THE PREVIOUS HIGH TEMP
FCST BY A 50-50 BLEND THE 00Z/06Z NAM 2M TEMPS. THIS HAS COOLED
FCST HIGHS ALONG THE I-80 CORRIDOR NORTHWARD.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CST TUE DEC 3 2013
...AN EXTENDED PERIOD OF HARSH WINTER COLD IS ON THE DOORSTEP AND
ONCE IT ARRIVES TONIGHT THERE ARE NO SIGNS OF IT RELEASING UNTIL
MID-MONTH APPROACHES...
ALOFT: THE COLD CORE ARCTIC LOW THAT WAS OVER SIBERIA 7 DAYS AGO
IS NOW ON OUR DOORSTEP /CURRENTLY OVER MT/. WESTERLY FLOW WILL
BECOME SW AS THE LOW BECOMES ELONGATED AND OPENS UP...EJECTING A
SHORTWAVE TROF ACROSS THE NRN PLAINS THIS AFTERNOON AND TONIGHT.
SFC: THE ARCTIC COLD FRONT WAS ALONG THE SD-NEB BORDER...WITH A
PRE-FRONTAL TROF EXTENDING E-W ACROSS NEB. BOTH OF THESE FEATURES
TO PRESS S...CROSSING THE FCST AREA BETWEEN 2 PM AND 8 PM.
BITTERLY COLD HIGH PRES OVER THE CANADIAN ROCKIES BEGINS BUILDING
IN TONIGHT. A LEE-SIDE LOW WILL MIGRATE DOWN THE FRONT RANGE
TODAY AND THEN EJECT ACROSS OK TONIGHT. THIS WILL MAINTAIN A
TIGHT PRES GRADIENT.
HI-RES MESOSCALE MODELS SUGGEST THE FOLLOWING APPROXIMATE TIMES
OF FRONTAL PASSAGE:
3 PM ORD-LEXINGTON
4 PM OSCEOLA-KEARNEY-ELWOOD
5 PM YORK-FRANKLIN-LONG ISLAND KS
6 PM GENEVA-SMITH CENTER KS-PHILLIPSBURG KS
7 PM MANKATO-OSBORNE-STOCKTON
8 PM BELOIT
EARLY THIS MORNING: A BATCH OF MULTI-LAYERED MID-HIGH CLOUDS WAS
MOVING THRU THE FCST AREA. CLOUD TOPS WERE WARMING. UEX/LNX
RADARS HAVE SHOWN SOME SMALL POCKETS OF PRECIP...BUT SUB-CLOUD
AIR IS TOO DRY FOR ANYTHING TO SURVIVE TO THE SURFACE.
TODAY: ONCE THE BATCH OF CLOUDS DEPARTS TO THE E...WE COULD SEE A
PERIOD OF SUBSTANTIAL SUNSHINE. LOOK FOR A RAPID WARM-UP. THIS
WILL BE THE LAST DAY OF MUCH WARMER THAN NORMAL TEMPS. HIGHS ARE
PRIMARILY BASED ON THE 21Z/2 BIAS CORRECTED SREF.
THE SATELLITE FOG/REFLECTIVITY PRODUCT SHOWS STRATUS OVERCAST
IMMEDIATELY BEHIND T HE FRONT. IT IS DISCONCERTING TO SEE IT
DROPPING INTO NRN NEB. THIS WILL NEED TO BE MONITORED AS
SUBSTANTIAL CHANGES WILL NEED TO OCCUR TO THE SHORT-TERM FCST.
THE 06Z NAM SUGGESTS THE STRATUS WILL DROP INTO AREAS N OF HWY
92...BUT THEN GET ERODED BY BOUNDARY LAYER MIXING.
POSSIBLE FCST SHORT-COMINGS: DO WE HAVE THE TIMING OF FRONTAL
PASSAGE CORRECT? THIS WILL HAVE SIGNIFICANT IMPLICATIONS ON THE
FCST. CONFIDENCE IN HOURLY TEMPS AND HIGHS ARE BELOW AVERAGE FROM
HWY 6 NORTHWARD.
IMMEDIATELY BEHIND THE FRONT EXPECT A RAPID INCREASE IN N WINDS
AND IT WILL CONTINUE THRU TONIGHT.
WIND: COOPERATIVE INSTITUTE FOR PRECIP SYSTEMS /CIPS/ TOP 10
ANALOGS OFFER A 50-60% CHANCE OF 30-35 KT WINDS. THE CHANCE FOR
36-40 KTS IS 30-40%. THE 00Z NAM HAS 30 KTS AS LOW AS 1000 FT AT
ORD WITH A MAX OF 32-34 KTS AVAILABLE AT THE TOP OF THE MIXED
LAYER. OVER THE REST OF S-CNTRL NEB 30 KTS IS FCST AS LOW AS 1500
FT WITH 32 KTS MAX. OVER N-CNTRL KS 30 KTS WILL BE AVAILABLE AT
THE TOP OF THE MIXED LAYER /2000 FT/. THIS MATCHES WELL WITH WHAT
IS OFFERED FROM THE CIPS ANALOGS. SO EXPECT THE HIGHEST GUSTS N OF
I-80...BUT THERE IS POTENTIAL FOR EVERYWHERE TO GUST TO 30 KTS
WITH THE HIGHEST PROBABILITY OVER S-CNTRL NEB. 06Z NAM CHECKED. IT
LOOKS A BIT MORE THREATENING WITH MAX GUSTS UP TO 35 KTS N OF HWY
6.
TONIGHT: CLOUDY WITH HARSH N WINDS. LOW TEMPS NEAR NORMAL.
AS FOR PRECIP TODAY-TONIGHT...A SHALLOW FRONTOGENETIC CIRCULATION
WILL NOT BE AIDED BY ANY DEEP-LAYER FORCING/LIFT. AND WHILE THE
LOW-LEVELS AND MID-LEVELS ABOVE 12K FT WILL BE AT OR NEAR
SATURATION ...THE 7-11K FT LAYER WILL BE DRY. SO PLAYED IT AS A
SLIGHT CHANCE FOR A LITTLE LIGHT RAIN/SNOW N OF HWY 92 LATE THIS
AFTERNOON AND A SLIGHT CHANCE OF LIGHT SNOW TONIGHT. BY 09Z...THE
BASE OF THE STRATUS WILL BECOME COLD ENOUGH FOR ICE TO FORM IN-
CLOUD. SO A SLIGHT CHANCE OF FLURRIES WAS INCLUDED FROM HWY 92
DOWN TO HWY 6 LATE TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM CST TUE DEC 3 2013
GUIDANCE SUGGESTS A MID TO UPPER LEVEL LONG WAVE TROUGH WILL
EXTEND FROM CENTRAL CANADA...SOUTHWEST INTO THE WESTERN CONUS AT
12Z WEDNESDAY. THIS LONG WAVE TROUGH IS EXPECTED TO PERSIST OVER
THE SAME AREAS THROUGH 12Z FRIDAY...AT WHICH TIME IT SHOULD MOVE
EAST/NORTHEAST AND WEAKEN. A SECOND MID TO UPPER LEVEL LONGWAVE
TROUGH IS THEN EXPECTED TO DEVELOP OVER THE WESTERN CONUS SATURDAY
INTO SATURDAY NIGHT AND PERSIST THROUGH THE END OF THE LONG TERM
FORECAST PERIOD. RESULTANT MID TO UPPER LEVEL FLOW OVER OUR AREA
IS EXPECTED TO REMAIN FROM THE SOUTHWEST 12Z WEDNESDAY THROUGH 12Z
FRIDAY...WITH QUASI-ZONAL FLOW EXPECTED FRIDAY INTO FRIDAY
NIGHT...AND SOUTHWEST FLOW ONCE AGAIN SATURDAY THROUGH THE END OF
THE LONG TERM FORECAST PERIOD. A CLOSED MID LEVEL LOW...EMBEDDED
WITHIN THE FIRST LONG WAVE TROUGH...IS EXPECTED OVER THE NORTHERN
PLAINS AT 12Z WEDNESDAY...WITH THIS MID LEVEL LOW EXPECTED TO
EJECT TO THE NORTHEAST...AWAY FROM THE LONG WAVE TROUGH...INTO
ONTARIO AND QUEBEC BETWEEN 12Z WEDNESDAY AND 12Z FRIDAY. A
SECONDARY MID LEVEL LOW IS ALSO EXPECTED TO MOVE SOUTH AND THEN
EAST FROM SASKATCHEWAN INTO THE NORTHERN PLAINS BETWEEN 12Z
WEDNESDAY AND 12Z FRIDAY. THIS SECONDARY MID LEVEL LOW IS THEN
EXPECTED TO MOVE EAST/NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY
AND ONTARIO...ALONG WITH THE LONG WAVE TROUGH...FRIDAY INTO FRIDAY
NIGHT. THERE ARE THEN INDICATIONS OF A MID LEVEL SHORTWAVE
EJECTING FROM THE WESTERN CONUS AND MOVING EAST ACROSS PORTIONS OF
THE CENTRAL AND SOUTHERN PLAINS ON SUNDAY. AT THE SURFACE AN AREA
LOW BAROMETRIC PRESSURE IS EXPECTED OVER THE UPPER MISSISSIPPI
VALLEY AT 12Z WEDNESDAY...WITH AN ASSOCIATED LOW LEVEL BAROCLINIC
ZONE EXTENDING SOUTH/SOUTHWEST FROM THE LOW INTO THE MID
MISSISSIPPI VALLEY AND SOUTHERN PLAINS. STRONG SURFACE RIDGING
SHOULD BE WORKING INTO THE CENTRAL PLAINS ON WEDNESDAY AS THE
FIRST MID LEVEL LOW AND SURFACE LOW DEPART TO THE NORTHEAST. THE
SURFACE RIDGE SHOULD THEN PERSIST ACROSS THE CENTRAL PLAINS
THROUGH FRIDAY AS THE SECONDARY MID LEVEL LOW ADVANCES SOUTH AND
THEN EAST FROM SASKATCHEWAN...INDUCING A WEAK AREA OF LOW
BAROMETRIC PRESSURE AT THE SURFACE ACROSS PORTIONS OF THE UPPER
MISSISSIPPI VALLEY. LEE SIDE TROUGHING ALONG THE FRONT RANGE IS
THEN EXPECTED TO DEVELOP FRIDAY NIGHT INTO SATURDAY.
FINALLY...THERE IS A LIKELIHOOD A SURFACE LOW WILL MOVE EAST
SOMEWHERE ACROSS THE CENTRAL AND/OR SOUTHERN PLAINS DURING THE DAY
SUNDAY AS THE MID LEVEL SHORTWAVE DOES THE SAME. GIVEN ALL
THIS...LOW LEVEL FLOW SHOULD REMAIN FROM THE NORTH/NORTHWEST
WEDNESDAY FRIDAY...WITH SOUTHERLY FLOW EXPECTED SATURDAY...AND
ANOTHER ROUND OF NORTHWESTERLY LOW LEVEL FLOW TOWARDS THE END OF
THE FORECAST PERIOD.
ALTHOUGH THERE COULD BE A WEAK RIBBON OF MID LEVEL THERMAL
ADVECTION GRAZING OUR NORTHWEST DURING THE DAY WEDNESDAY...AT THIS
TIME IT APPEARS ANY SUBSTANTIAL OMEGA WILL REMAIN RELEGATED
NORTH/NORTHEAST AND WEST OF OUR AREA...EITHER IN CLOSER PROXIMITY
TO THE DEPARTING MID LEVEL LOW TO OUR NORTH/NORTHEAST OR IN CLOSER
PROXIMITY TO THE LONGWAVE TROUGH AXIS TO OUR WEST. WENT AHEAD WITH
DRY CONDITIONS ON WEDNESDAY AS A RESULT. HEADING INTO WEDNESDAY
NIGHT...THERE ARE INDICATIONS OF A ~90KT MID LEVEL JET STREAK
MOVING INTO THE MID MISSISSIPPI VALLEY...WITH THE RIGHT-REAR
QUADRANT OF THIS STREAK PERHAPS GENERATING ENOUGH OF A DIRECT
THERMAL CIRCULATION AND RESULTANT OMEGA FOR PRECIPITATION
PRODUCTION ACROSS PORTIONS OF OUR CWA. QPF FIELDS FROM THE
NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL SEEM TO SUGGEST OUR
WEST/SOUTHWEST CWA STAND THE BEST CHANCE AT OBSERVING MEASURABLE
PRECIPITATION. AS A RESULT...WENT AHEAD WITH ~20% POPS ACROSS OUR
WEST/SOUTHWEST 00Z-06Z THURSDAY. IT APPEARS THE MID LEVEL JET
STREAK WILL PERSIST THURSDAY INTO THURSDAY NIGHT AS WELL...HOWEVER
IT ALSO APPEARS THE JET STREAK AXIS WILL SHIFT EAST/SOUTHEAST
SOMEWHAT...THUS POSITIONING THE RIGHT-REAR QUADRANT AND RESULTANT
OMEGA SLIGHTLY SOUTH/SOUTHEAST OF OUR AREA AS WELL. ALTHOUGH SOME
GUIDANCE SUGGESTS OUR EXTREME SOUTH COULD OBSERVE MEASURABLE
PRECIPITATION AT ONE TIME OR ANOTHER THURSDAY AND THURSDAY
NIGHT...THERE REALLY IS NO AGREEMENT BETWEEN THE MODELS AS TO
WHETHER THIS WILL OCCUR THURSDAY...THURSDAY NIGHT...OR AT ALL.
ALTHOUGH WE PROBABLY CANNOT COMPLETELY RULE OUT A PERIOD OF VERY
LIGHT PRECIPITATION AT SOME POINT DURING THE THURSDAY-THURSDAY
NIGHT TIME PERIOD...GIVEN THE PRIMARY AXIS OF OMEGA APPEARS TO
REMAIN SOUTH/SOUTHEAST OF OUR AREA AND THE VERY LOW CONFIDENCE
THAT ANYONE WOULD ACTUALLY OBSERVE MEASURABLE
PRECIPITATION...OPTED TO REMOVE MEASURABLE PRECIPITATION FROM THE
THURSDAY-THURSDAY NIGHT TIME PERIOD AND INSTEAD GO AHEAD WITH A
MENTION OF SNOW FLURRIES. THE APPROACH OF THE MID LEVEL SHORTWAVE
SUNDAY COULD THEN BRING A CHANCE FOR PRECIPITATION SUNDAY.
ALLBLEND RESPONDED BY PROVIDING ~30% POPS TO THE AREA AND THESE
POPS WERE LEFT UNCHANGED FOR THE MOST PART.
FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE NAM
AND OPERATIONAL GFS...SUGGEST AN INVASION OF ARCTIC AIR WILL KEEP
THE LOWER TROPOSPHERE COLD ENOUGH FOR SNOW PRODUCTION DURING THE
LONG TERM FORECAST PERIOD. ANY SNOWFALL THAT IS REALIZED ACROSS
OUR CWA WEDNESDAY NIGHT INTO THURSDAY SHOULD REMAIN VERY LIGHT.
THAT BEING SAID...THE VERY COLD/DRY LOWER TROPOSPHERE SUGGESTS
SNOW-WATER RATIOS WILL BE VERY HIGH...SOMEWHERE IN 20-30:1
RANGE...THUS EVEN A COUPLE HUNDREDTHS OF AN INCH OF LIQUID
PRECIPITATION...WHICH IS FORECAST ACROSS OUR WEST/SOUTHWEST 00-06Z
THURSDAY...COULD BE CAPABLE OF PRODUCING ~0.5" OF SNOWFALL. THE
MID LEVEL SHORTWAVE WHICH COULD POTENTIALLY IMPACT OUR AREA NEXT
SUNDAY IS SLIGHTLY MORE INTERESTING...WITH THE OPERATIONAL GFS AND
EC BOTH SUGGESTING SNOWFALL ACCUMULATION IN EXCESS OF AN INCH WILL
BE REALIZED ACROSS THE CWA. CERTAINLY SOMETHING TO CONTINUE
MONITORING.
ARCTIC AIR REMAINS POISED TO OCCUPY THE CENTRAL PLAINS DURING THE
LONG TERM FORECAST PERIOD. TEMPERATURES WITHIN THE SOURCE REGION
OF THE ARCTIC AIRMASS...CURRENTLY ACROSS PORTIONS OF
ALBERTA...SASKATCHEWAN AND MANITOBA...ONLY CLIMBED INTO THE TEENS
AND 20S MONDAY AFTERNOON...AND THESE VALUES ARE ALSO BEING
PRESENTED TO OUR AREA BY MULTIPLE SETS OF GUIDANCE THURSDAY
ONWARD. WEDNESDAY MAY ACTUALLY BE A TOUCH WARMER AS THE TRUE MASS
OF ARCTIC AIR WILL TAKE SOME TIME TO WORK INTO THE REGION...THUS
WEDNESDAY AFTERNOON HIGHS RANGING FROM THE 20S TO NEAR 30 ARE
FORECAST. BASED ON THE SOURCE REGION OF THE INCOMING ARCTIC AIR
MASS...IT APPEARS LIKELY OVERNIGHT LOWS IN THE SINGLE DIGITS WILL
ALSO BE COMMON THURSDAY ONWARD.
FINALLY...LATEST GUIDANCE SUGGESTS A SUSTAINED LOW LEVEL WIND
FIELD AT AROUND 15KTS...WORKING IN CONCERT WITH THE AFOREMENTIONED
SINGLE DIGIT OVERNIGHT LOWS...WILL PROVIDE APPARENT TEMPERATURE
VALUES BETWEEN -15 AND -19 DEGREES F ACROSS NORTHWESTERN PORTIONS
OF OUR CWA WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. WILL GO
AHEAD AND OUTLOOK THESE CONDITIONS IN THE HWO...PRIMARILY FOR
LOCATIONS ALONG AND NORTHWEST OF A LINE OF LEXINGTON...TO LOUP
CITY AND GREELEY. ALTHOUGH THESE VALUES DO NOT JUSTIFY ADVISORY
ISSUANCE...THIS WILL CERTAINLY NEED TO BE MONITORED THROUGH THE
NEXT COUPLE DAYS IN CASE HEADLINES BECOME NECESSARY. ALTHOUGH NOT
AS WIDESPREAD...APPARENT TEMPERATURE VALUES ARE ALSO FORECAST TO
APPROACH -15 DEGREES F ACROSS VALLEY AND GREELEY COUNTIES EARLY
FRIDAY MORNING AS WELL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 603 AM CST TUE DEC 3 2013
TODAY: FOG/REFLECTIVITY SATELLITE IMAGERY SHOWS IFR STRATUS IS
SURGING S TOWARD GRI AT 12Z. ODX IS NOW OVC008 AND HAVE TIMED
THIS INTO GRI AT 14Z. THE STATISTICAL MODEL OUTPUT IS NOT HANDLING
THIS STRATUS. SO THIS FCST IS BASED ON CURRENT TRENDS AND MODEL RH
FIELDS...WHICH INDICATE THE LEADING EDGE OF THE STRATUS COULD
BEGIN ERODING AROUND MIDDAY...ALLOWING FOR A COUPLE HRS OF VFR
CIGS. IF THIS OCCURS...STRATUS WILL RE-INVADE AROUND 21Z WITH
FRONTAL PASSAGE. SHOULD SEE A SIGNIFICANT INCREASE IN N WINDS...
BUT THERE IS UNCERTAINTY ON IF ITS GRADUAL OR ABRUPT. CONFIDENCE:
AVERAGE
TONIGHT: STATISTICAL MODEL OUTPUT SUGGESTS MVFR CIGS...BUT CURRENT
OBS UPSTREAM ARE LARGELY IFR. THE TAF CIG IS MORE PESSIMISTIC THAN
MOS BUT NOT AS PESSIMISTIC AS CURRENT OBS UPSTREAM. BE AWARE THAT
CIGS MAY NEED TO BE DOWNGRADED A CATEGORY LATER TODAY. CONFIDENCE:
AVERAGE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
604 AM CST TUE DEC 3 2013
.UPDATE...
ISSUED AT 603 AM CST TUE DEC 3 2013
WITH THE INITIAL FCST ISSUANCE AT 4 AM...WAS UNSURE WHY THE
00Z/06Z NAM TEMPS WERE FCST TO BEHAVE THE WAY THEY WERE DEPICTED
AND NOW IT IS CLEAR AS WE SEE STRATUS SURGING S ACROSS CNTRL NEB.
THE SKY FCST HAS BEEN ENHANCED BY USING THE 13 KM RAP WHICH HAS AN
EXCELLENT HANDLE ON THE STRATUS...EVEN DEPICTING ITS LEADING EDGE
ERODING AROUND MIDDAY. HAVE ALSO REPLACED THE PREVIOUS HIGH TEMP
FCST BY A 50-50 BLEND THE 00Z/06Z NAM 2M TEMPS. THIS HAS COOLED
FCST HIGHS ALONG THE I-80 CORRIDOR NORTHWARD.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CST TUE DEC 3 2013
...AN EXTENDED PERIOD OF HARSH WINTER COLD IS ON THE DOORSTEP AND
ONCE IT ARRIVES TONIGHT THERE ARE NO SIGNS OF IT RELEASING UNTIL
MID-MONTH APPROACHES...
ALOFT: THE COLD CORE ARCTIC LOW THAT WAS OVER SIBERIA 7 DAYS AGO
IS NOW ON OUR DOORSTEP /CURRENTLY OVER MT/. WESTERLY FLOW WILL
BECOME SW AS THE LOW BECOMES ELONGATED AND OPENS UP...EJECTING A
SHORTWAVE TROF ACROSS THE NRN PLAINS THIS AFTERNOON AND TONIGHT.
SFC: THE ARCTIC COLD FRONT WAS ALONG THE SD-NEB BORDER...WITH A
PRE-FRONTAL TROF EXTENDING E-W ACROSS NEB. BOTH OF THESE FEATURES
TO PRESS S...CROSSING THE FCST AREA BETWEEN 2 PM AND 8 PM.
BITTERLY COLD HIGH PRES OVER THE CANADIAN ROCKIES BEGINS BUILDING
IN TONIGHT. A LEE-SIDE LOW WILL MIGRATE DOWN THE FRONT RANGE
TODAY AND THEN EJECT ACROSS OK TONIGHT. THIS WILL MAINTAIN A
TIGHT PRES GRADIENT.
HI-RES MESOSCALE MODELS SUGGEST THE FOLLOWING APPROXIMATE TIMES
OF FRONTAL PASSAGE:
3 PM ORD-LEXINGTON
4 PM OSCEOLA-KEARNEY-ELWOOD
5 PM YORK-FRANKLIN-LONG ISLAND KS
6 PM GENEVA-SMITH CENTER KS-PHILLIPSBURG KS
7 PM MANKATO-OSBORNE-STOCKTON
8 PM BELOIT
EARLY THIS MORNING: A BATCH OF MULTI-LAYERED MID-HIGH CLOUDS WAS
MOVING THRU THE FCST AREA. CLOUD TOPS WERE WARMING. UEX/LNX
RADARS HAVE SHOWN SOME SMALL POCKETS OF PRECIP...BUT SUB-CLOUD
AIR IS TOO DRY FOR ANYTHING TO SURVIVE TO THE SURFACE.
TODAY: ONCE THE BATCH OF CLOUDS DEPARTS TO THE E...WE COULD SEE A
PERIOD OF SUBSTANTIAL SUNSHINE. LOOK FOR A RAPID WARM-UP. THIS
WILL BE THE LAST DAY OF MUCH WARMER THAN NORMAL TEMPS. HIGHS ARE
PRIMARILY BASED ON THE 21Z/2 BIAS CORRECTED SREF.
THE SATELLITE FOG/REFLECTIVITY PRODUCT SHOWS STRATUS OVERCAST
IMMEDIATELY BEHIND T HE FRONT. IT IS DISCONCERTING TO SEE IT
DROPPING INTO NRN NEB. THIS WILL NEED TO BE MONITORED AS
SUBSTANTIAL CHANGES WILL NEED TO OCCUR TO THE SHORT-TERM FCST.
THE 06Z NAM SUGGESTS THE STRATUS WILL DROP INTO AREAS N OF HWY
92...BUT THEN GET ERODED BY BOUNDARY LAYER MIXING.
POSSIBLE FCST SHORT-COMINGS: DO WE HAVE THE TIMING OF FRONTAL
PASSAGE CORRECT? THIS WILL HAVE SIGNIFICANT IMPLICATIONS ON THE
FCST. CONFIDENCE IN HOURLY TEMPS AND HIGHS ARE BELOW AVERAGE FROM
HWY 6 NORTHWARD.
IMMEDIATELY BEHIND THE FRONT EXPECT A RAPID INCREASE IN N WINDS
AND IT WILL CONTINUE THRU TONIGHT.
WIND: COOPERATIVE INSTITUTE FOR PRECIP SYSTEMS /CIPS/ TOP 10
ANALOGS OFFER A 50-60% CHANCE OF 30-35 KT WINDS. THE CHANCE FOR
36-40 KTS IS 30-40%. THE 00Z NAM HAS 30 KTS AS LOW AS 1000 FT AT
ORD WITH A MAX OF 32-34 KTS AVAILABLE AT THE TOP OF THE MIXED
LAYER. OVER THE REST OF S-CNTRL NEB 30 KTS IS FCST AS LOW AS 1500
FT WITH 32 KTS MAX. OVER N-CNTRL KS 30 KTS WILL BE AVAILABLE AT
THE TOP OF THE MIXED LAYER /2000 FT/. THIS MATCHES WELL WITH WHAT
IS OFFERED FROM THE CIPS ANALOGS. SO EXPECT THE HIGHEST GUSTS N OF
I-80...BUT THERE IS POTENTIAL FOR EVERYWHERE TO GUST TO 30 KTS
WITH THE HIGHEST PROBABILITY OVER S-CNTRL NEB. 06Z NAM CHECKED. IT
LOOKS A BIT MORE THREATENING WITH MAX GUSTS UP TO 35 KTS N OF HWY
6.
TONIGHT: CLOUDY WITH HARSH N WINDS. LOW TEMPS NEAR NORMAL.
AS FOR PRECIP TODAY-TONIGHT...A SHALLOW FRONTOGENETIC CIRCULATION
WILL NOT BE AIDED BY ANY DEEP-LAYER FORCING/LIFT. AND WHILE THE
LOW-LEVELS AND MID-LEVELS ABOVE 12K FT WILL BE AT OR NEAR
SATURATION ...THE 7-11K FT LAYER WILL BE DRY. SO PLAYED IT AS A
SLIGHT CHANCE FOR A LITTLE LIGHT RAIN/SNOW N OF HWY 92 LATE THIS
AFTERNOON AND A SLIGHT CHANCE OF LIGHT SNOW TONIGHT. BY 09Z...THE
BASE OF THE STRATUS WILL BECOME COLD ENOUGH FOR ICE TO FORM IN-
CLOUD. SO A SLIGHT CHANCE OF FLURRIES WAS INCLUDED FROM HWY 92
DOWN TO HWY 6 LATE TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM CST TUE DEC 3 2013
GUIDANCE SUGGESTS A MID TO UPPER LEVEL LONG WAVE TROUGH WILL
EXTEND FROM CENTRAL CANADA...SOUTHWEST INTO THE WESTERN CONUS AT
12Z WEDNESDAY. THIS LONG WAVE TROUGH IS EXPECTED TO PERSIST OVER
THE SAME AREAS THROUGH 12Z FRIDAY...AT WHICH TIME IT SHOULD MOVE
EAST/NORTHEAST AND WEAKEN. A SECOND MID TO UPPER LEVEL LONGWAVE
TROUGH IS THEN EXPECTED TO DEVELOP OVER THE WESTERN CONUS SATURDAY
INTO SATURDAY NIGHT AND PERSIST THROUGH THE END OF THE LONG TERM
FORECAST PERIOD. RESULTANT MID TO UPPER LEVEL FLOW OVER OUR AREA
IS EXPECTED TO REMAIN FROM THE SOUTHWEST 12Z WEDNESDAY THROUGH 12Z
FRIDAY...WITH QUASI-ZONAL FLOW EXPECTED FRIDAY INTO FRIDAY
NIGHT...AND SOUTHWEST FLOW ONCE AGAIN SATURDAY THROUGH THE END OF
THE LONG TERM FORECAST PERIOD. A CLOSED MID LEVEL LOW...EMBEDDED
WITHIN THE FIRST LONG WAVE TROUGH...IS EXPECTED OVER THE NORTHERN
PLAINS AT 12Z WEDNESDAY...WITH THIS MID LEVEL LOW EXPECTED TO
EJECT TO THE NORTHEAST...AWAY FROM THE LONG WAVE TROUGH...INTO
ONTARIO AND QUEBEC BETWEEN 12Z WEDNESDAY AND 12Z FRIDAY. A
SECONDARY MID LEVEL LOW IS ALSO EXPECTED TO MOVE SOUTH AND THEN
EAST FROM SASKATCHEWAN INTO THE NORTHERN PLAINS BETWEEN 12Z
WEDNESDAY AND 12Z FRIDAY. THIS SECONDARY MID LEVEL LOW IS THEN
EXPECTED TO MOVE EAST/NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY
AND ONTARIO...ALONG WITH THE LONG WAVE TROUGH...FRIDAY INTO FRIDAY
NIGHT. THERE ARE THEN INDICATIONS OF A MID LEVEL SHORTWAVE
EJECTING FROM THE WESTERN CONUS AND MOVING EAST ACROSS PORTIONS OF
THE CENTRAL AND SOUTHERN PLAINS ON SUNDAY. AT THE SURFACE AN AREA
LOW BAROMETRIC PRESSURE IS EXPECTED OVER THE UPPER MISSISSIPPI
VALLEY AT 12Z WEDNESDAY...WITH AN ASSOCIATED LOW LEVEL BAROCLINIC
ZONE EXTENDING SOUTH/SOUTHWEST FROM THE LOW INTO THE MID
MISSISSIPPI VALLEY AND SOUTHERN PLAINS. STRONG SURFACE RIDGING
SHOULD BE WORKING INTO THE CENTRAL PLAINS ON WEDNESDAY AS THE
FIRST MID LEVEL LOW AND SURFACE LOW DEPART TO THE NORTHEAST. THE
SURFACE RIDGE SHOULD THEN PERSIST ACROSS THE CENTRAL PLAINS
THROUGH FRIDAY AS THE SECONDARY MID LEVEL LOW ADVANCES SOUTH AND
THEN EAST FROM SASKATCHEWAN...INDUCING A WEAK AREA OF LOW
BAROMETRIC PRESSURE AT THE SURFACE ACROSS PORTIONS OF THE UPPER
MISSISSIPPI VALLEY. LEE SIDE TROUGHING ALONG THE FRONT RANGE IS
THEN EXPECTED TO DEVELOP FRIDAY NIGHT INTO SATURDAY.
FINALLY...THERE IS A LIKELIHOOD A SURFACE LOW WILL MOVE EAST
SOMEWHERE ACROSS THE CENTRAL AND/OR SOUTHERN PLAINS DURING THE DAY
SUNDAY AS THE MID LEVEL SHORTWAVE DOES THE SAME. GIVEN ALL
THIS...LOW LEVEL FLOW SHOULD REMAIN FROM THE NORTH/NORTHWEST
WEDNESDAY FRIDAY...WITH SOUTHERLY FLOW EXPECTED SATURDAY...AND
ANOTHER ROUND OF NORTHWESTERLY LOW LEVEL FLOW TOWARDS THE END OF
THE FORECAST PERIOD.
ALTHOUGH THERE COULD BE A WEAK RIBBON OF MID LEVEL THERMAL
ADVECTION GRAZING OUR NORTHWEST DURING THE DAY WEDNESDAY...AT THIS
TIME IT APPEARS ANY SUBSTANTIAL OMEGA WILL REMAIN RELEGATED
NORTH/NORTHEAST AND WEST OF OUR AREA...EITHER IN CLOSER PROXIMITY
TO THE DEPARTING MID LEVEL LOW TO OUR NORTH/NORTHEAST OR IN CLOSER
PROXIMITY TO THE LONGWAVE TROUGH AXIS TO OUR WEST. WENT AHEAD WITH
DRY CONDITIONS ON WEDNESDAY AS A RESULT. HEADING INTO WEDNESDAY
NIGHT...THERE ARE INDICATIONS OF A ~90KT MID LEVEL JET STREAK
MOVING INTO THE MID MISSISSIPPI VALLEY...WITH THE RIGHT-REAR
QUADRANT OF THIS STREAK PERHAPS GENERATING ENOUGH OF A DIRECT
THERMAL CIRCULATION AND RESULTANT OMEGA FOR PRECIPITATION
PRODUCTION ACROSS PORTIONS OF OUR CWA. QPF FIELDS FROM THE
NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL SEEM TO SUGGEST OUR
WEST/SOUTHWEST CWA STAND THE BEST CHANCE AT OBSERVING MEASURABLE
PRECIPITATION. AS A RESULT...WENT AHEAD WITH ~20% POPS ACROSS OUR
WEST/SOUTHWEST 00Z-06Z THURSDAY. IT APPEARS THE MID LEVEL JET
STREAK WILL PERSIST THURSDAY INTO THURSDAY NIGHT AS WELL...HOWEVER
IT ALSO APPEARS THE JET STREAK AXIS WILL SHIFT EAST/SOUTHEAST
SOMEWHAT...THUS POSITIONING THE RIGHT-REAR QUADRANT AND RESULTANT
OMEGA SLIGHTLY SOUTH/SOUTHEAST OF OUR AREA AS WELL. ALTHOUGH SOME
GUIDANCE SUGGESTS OUR EXTREME SOUTH COULD OBSERVE MEASURABLE
PRECIPITATION AT ONE TIME OR ANOTHER THURSDAY AND THURSDAY
NIGHT...THERE REALLY IS NO AGREEMENT BETWEEN THE MODELS AS TO
WHETHER THIS WILL OCCUR THURSDAY...THURSDAY NIGHT...OR AT ALL.
ALTHOUGH WE PROBABLY CANNOT COMPLETELY RULE OUT A PERIOD OF VERY
LIGHT PRECIPITATION AT SOME POINT DURING THE THURSDAY-THURSDAY
NIGHT TIME PERIOD...GIVEN THE PRIMARY AXIS OF OMEGA APPEARS TO
REMAIN SOUTH/SOUTHEAST OF OUR AREA AND THE VERY LOW CONFIDENCE
THAT ANYONE WOULD ACTUALLY OBSERVE MEASURABLE
PRECIPITATION...OPTED TO REMOVE MEASURABLE PRECIPITATION FROM THE
THURSDAY-THURSDAY NIGHT TIME PERIOD AND INSTEAD GO AHEAD WITH A
MENTION OF SNOW FLURRIES. THE APPROACH OF THE MID LEVEL SHORTWAVE
SUNDAY COULD THEN BRING A CHANCE FOR PRECIPITATION SUNDAY.
ALLBLEND RESPONDED BY PROVIDING ~30% POPS TO THE AREA AND THESE
POPS WERE LEFT UNCHANGED FOR THE MOST PART.
FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE NAM
AND OPERATIONAL GFS...SUGGEST AN INVASION OF ARCTIC AIR WILL KEEP
THE LOWER TROPOSPHERE COLD ENOUGH FOR SNOW PRODUCTION DURING THE
LONG TERM FORECAST PERIOD. ANY SNOWFALL THAT IS REALIZED ACROSS
OUR CWA WEDNESDAY NIGHT INTO THURSDAY SHOULD REMAIN VERY LIGHT.
THAT BEING SAID...THE VERY COLD/DRY LOWER TROPOSPHERE SUGGESTS
SNOW-WATER RATIOS WILL BE VERY HIGH...SOMEWHERE IN 20-30:1
RANGE...THUS EVEN A COUPLE HUNDREDTHS OF AN INCH OF LIQUID
PRECIPITATION...WHICH IS FORECAST ACROSS OUR WEST/SOUTHWEST 00-06Z
THURSDAY...COULD BE CAPABLE OF PRODUCING ~0.5" OF SNOWFALL. THE
MID LEVEL SHORTWAVE WHICH COULD POTENTIALLY IMPACT OUR AREA NEXT
SUNDAY IS SLIGHTLY MORE INTERESTING...WITH THE OPERATIONAL GFS AND
EC BOTH SUGGESTING SNOWFALL ACCUMULATION IN EXCESS OF AN INCH WILL
BE REALIZED ACROSS THE CWA. CERTAINLY SOMETHING TO CONTINUE
MONITORING.
ARCTIC AIR REMAINS POISED TO OCCUPY THE CENTRAL PLAINS DURING THE
LONG TERM FORECAST PERIOD. TEMPERATURES WITHIN THE SOURCE REGION
OF THE ARCTIC AIRMASS...CURRENTLY ACROSS PORTIONS OF
ALBERTA...SASKATCHEWAN AND MANITOBA...ONLY CLIMBED INTO THE TEENS
AND 20S MONDAY AFTERNOON...AND THESE VALUES ARE ALSO BEING
PRESENTED TO OUR AREA BY MULTIPLE SETS OF GUIDANCE THURSDAY
ONWARD. WEDNESDAY MAY ACTUALLY BE A TOUCH WARMER AS THE TRUE MASS
OF ARCTIC AIR WILL TAKE SOME TIME TO WORK INTO THE REGION...THUS
WEDNESDAY AFTERNOON HIGHS RANGING FROM THE 20S TO NEAR 30 ARE
FORECAST. BASED ON THE SOURCE REGION OF THE INCOMING ARCTIC AIR
MASS...IT APPEARS LIKELY OVERNIGHT LOWS IN THE SINGLE DIGITS WILL
ALSO BE COMMON THURSDAY ONWARD.
FINALLY...LATEST GUIDANCE SUGGESTS A SUSTAINED LOW LEVEL WIND
FIELD AT AROUND 15KTS...WORKING IN CONCERT WITH THE AFOREMENTIONED
SINGLE DIGIT OVERNIGHT LOWS...WILL PROVIDE APPARENT TEMPERATURE
VALUES BETWEEN -15 AND -19 DEGREES F ACROSS NORTHWESTERN PORTIONS
OF OUR CWA WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. WILL GO
AHEAD AND OUTLOOK THESE CONDITIONS IN THE HWO...PRIMARILY FOR
LOCATIONS ALONG AND NORTHWEST OF A LINE OF LEXINGTON...TO LOUP
CITY AND GREELEY. ALTHOUGH THESE VALUES DO NOT JUSTIFY ADVISORY
ISSUANCE...THIS WILL CERTAINLY NEED TO BE MONITORED THROUGH THE
NEXT COUPLE DAYS IN CASE HEADLINES BECOME NECESSARY. ALTHOUGH NOT
AS WIDESPREAD...APPARENT TEMPERATURE VALUES ARE ALSO FORECAST TO
APPROACH -15 DEGREES F ACROSS VALLEY AND GREELEY COUNTIES EARLY
FRIDAY MORNING AS WELL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 603 AM CST TUE DEC 3 2013
TODAY: FOG/REFLECTIVITY SATELLITE IMAGERY SHOWS IFR STRATUS IS
SURGING S TOWARD GRI AT 12Z. ODX IS NOW OVC008 AND HAVE TIMED
THIS INTO GRI AT 14Z. THE STATISTICAL MODEL OUTPUT IS NOT HANDLING
THIS STRATUS. SO THIS FCST IS BASED ON CURRENT TRENDS AND MODEL RH
FIELDS...WHICH INDICATE THE LEADING EDGE OF THE STRATUS COULD
BEGIN ERODING AROUND MIDDAY...ALLOWING FOR A COUPLE HRS OF VFR
CIGS. IF THIS OCCURS...STRATUS WILL RE-INVADE AROUND 21Z WITH
FRONTAL PASSAGE. SHOULD SEE A SIGNIFICANT INCREASE IN N WINDS...
BUT THERE IS UNCERTAINTY ON IF ITS GRADUAL OR ABRUPT. CONFIDENCE:
AVERAGE
TONIGHT: STATISTICAL MODEL OUTPUT SUGGESTS MVFR CIGS...BUT CURRENT
OBS UPSTREAM ARE LARGELY IFR. THE TAF CIG IS MORE PESSIMISTIC THAN
MOS BUT NOT AS PESSIMISTIC AS CURRENT OBS UPSTREAM. BE AWARE THAT
CIGS MAY NEED TO BE DOWNGRADED A CATEGORY LATER TODAY. CONFIDENCE:
AVERAGE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
706 AM EST TUE DEC 3 2013
.SYNOPSIS...COASTAL LOW PRESSURE WILL MOVE NORTHEAST AWAY FROM NORTH
CAROLINA THIS MORNING. WEAK HIGH PRESSURE WILL BUILD OVER THE AREA
TODAY AND TONIGHT...THEN SHIFT OFFSHORE WEDNESDAY AS A WARM FRONT
APPROACHES FROM THE SOUTH.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 235 AM TUESDAY...
TODAY WILL MARK THE START OF A PERIOD OF VERY LITTLE SUNSHINE. THE
LATEST SURFACE ANALYSIS SHOWS THE LOW OFF THE NRN NC OUTER BANKS
(ALONG THE OLD FRONT) HEADING ENE AWAY FROM OUR AREA (PUSHED BY THE
BAGGY MID LEVEL TROUGH NOW CROSSING THE AREA)... WHILE WEAK NARROW
HIGH PRESSURE SLIDES IN FROM THE WEST. THIS SURFACE RIDGE WILL BE
PROGRESSIVE... MOVING TO OUR EAST THIS AFTERNOON AS A LOW LEVEL WARM
FRONTAL ZONE (NOW STRETCHING ACROSS E TN THROUGH GA) HEADS SLOWLY NE
TOWARD CENTRAL NC. PATCHY LIGHT RAIN OVER AL/GA (FUELED IN PART BY
LOW LEVEL MOIST UPGLIDE AND WEAK MID LEVEL DPVA) IS MOVING EASTWARD
INTO SC AND SW NC... AND THE LATEST HRRR RUNS BRING THIS INTO OUR
FAR SW CWA EARLY THIS MORNING BEFORE IT DISSIPATES... SUPPORTING THE
IDEA THAT IT WILL ENCOUNTER ENOUGH LOW LEVEL DRY AIR IN PLACE TO BE
OF LITTLE CONSEQUENCE. WILL RETAIN A LOW CHANCE OF A SPRINKLE IN THE
SW THROUGH JUST PAST DAYBREAK. LOW LEVEL MOISTURE SHOULD CONTINUE TO
INCREASE FROM SW TO NE ACROSS CENTRAL NC THROUGH TODAY... WITH NE
SECTIONS SEEING THE MOST SUNSHINE (ALTHOUGH THIS TOO SHOULD BE
FILTERED) AND THE WEST SEEING VERY LITTLE SUN AS THE LOW LEVEL MOIST
UPGLIDE AT 290-300K RAMPS UP AND DEEPENS EARLY. MODELS DEPICT A VERY
WEAK MID LEVEL WAVE TRACKING FROM THE CENTRAL PLAINS THROUGH THE
MIDATLANTIC AREA TONIGHT... AND THE INCREASING MOISTURE COMBINED
WITH THIS WEAK LIFT ALOFT AND ALSO-WEAK LOWER-LEVEL LIFT WITH THE
APPROACHING WARM FRONT (EXPECTED TO PUSH THROUGH SC TOWARD THE NC
BORDER BY MIDNIGHT AND INTO FAR SRN AND SE NC OVERNIGHT) INCLUDING
WEAK 850 MB MASS CONVERGENCE WARRANTS A CHANCE OF LIGHT RAIN OVER
THE WRN AND EXTREME SRN CWA STARTING LATE THIS AFTERNOON GOING INTO
THIS EVENING. EXPECT LOW CHANCES TO THEN SPREAD NORTHWARD THROUGH NC
OVERNIGHT... BUT THE ANTECEDENT DRIER AIR HERE AND WEAK NATURE OF
THE ASCENT SHOULD GREATLY LIMIT COVERAGE AND AMOUNTS FARTHER NORTH.
THIS POP SCENARIO IS SUPPORTED BY THE SREF AND LATEST HI-RES WRF
RUNS. THE COOLEST TEMPS ACROSS THE AREA TODAY SHOULD BE IN THE SW
WHERE CLOUDS WILL BE THICKEST AND MOST PERSISTENT. THICKNESSES STILL
A BIT BELOW NORMAL FAVOR BELOW-NORMAL HIGHS OF 57-62. MILD LOWS OF
43-50... INCLUDING A SMALL UPWARD BUMP IN THE SOUTHERN CWA WITH
THICK CLOUDS AND THE NEARING WARM FRONT. -GIH
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 305 AM TUESDAY...
THE LOW LEVEL WARM FRONT IS EXPECTED TO CONTINUE ITS SLOW NORTHWARD
PROGRESSION THROUGH NC... ALTHOUGH THE MODELS SUGGEST THAT WHILE THE
925-850 MB FRONT SHOULD PROGRESS TO OUR NORTH... THE SURFACE WARM
FRONTAL ZONE MAY NOT QUITE GET ALL OF THE WAY THROUGH OUR CWA AS A
POCKET OF WEAKLY STABLE AIR MAY LINGER OVER THE NW PIEDMONT. WITHIN
THE DEEP SW FLOW... HIGH PW AIR WILL CONTINUE TO FUNNEL INTO
CENTRAL/ERN NC WITH VALUES AT OR OVER 1 INCH... NEAR OR EXCEEDING
200% OF NORMAL... WITH STEADY MOIST ISENTROPIC UPGLIDE OVER THE
AREA... PARTICULARLY WED MORNING... DECREASING AS THE WARM FRONT
JUST ALOFT SHIFTS TO OUR NORTH WITH UPGLIDE BECOMING WEAKER AND MORE
SHALLOW. THE EARLIER FORECAST SHOWS THIS TREND FAIRLY WELL... WITH
SLIGHT CHANCE POPS AND LOWER AMOUNTS IN THE NW WITH CHANCE POPS AND
A BIT MORE OVER THE SE CWA. WITH DECENT AGREEMENT ON THIS PATTERN
AMONGST THE MOST RECENT MODELS RUNS... WILL RETAIN THIS
CONFIGURATION... FOCUSING THE HIGHER (BUT STILL LESS THAN A 40%
CHANCE) POPS IN THE SE IN THE MORNING BEFORE TAPERING THEM OFF IN
THE AFTERNOON WITH THE DEPARTURE OF THE BETTER (YET STILL MODEST)
FORCING FOR ASCENT AND A BRIEF DIP IN THE PRECIP WATER. THE FLAT
FLOW ALOFT THAT IS GENTLY ANTICYCLONIC AND THE FOCUS OF THE WEAK
FORCING CONFINED TO THE LOWER ALTITUDES WILL LIMIT OVERALL PRECIP
TOTALS. EXPECT IT TO REMAIN MOSTLY CLOUDY TO CLOUDY... ESPECIALLY
OVERNIGHT AS ANOTHER SURGE IN VERY HIGH PW SPREADS IN FROM THE SW.
HIGHS FROM NEAR 60 NW (WHERE THE SLIGHTLY COOLER AND MORE STABLE AIR
WILL HOLD ON LONGER INTO WED) TO AROUND 70 SE (THANKS TO THICKNESSES
CLIMBING WELL ABOVE NORMAL). MILD LOWS 53-58. -GIH
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 250 AM MONDAY...
AN AMPLIFIED LONGWAVE PATTERN IN THE MEDIUM RANGE WILL FEATURE A
TROUGH OVER THE WESTERN US AND A RIDGE OVER THE WESTERN
ATLANTIC...WHICH WILL LEAD TO SPEEDY SOUTHWESTERLY FLOW ALOFT
BETWEEN THE TWO AND ACTIVE WESTERN OVER THE EASTERN US. AHEAD OF A
SLOWLY EVOLVING COLD FRONT OVER THE MIDWEST...LOW LEVEL THICKNESSES
OVER CENTRAL NC ARE FORECAST TO REACH AROUND 1375M THURSDAY AND
1385M ON FRIDAY...AIDED BY A STEADY SOUTHWESTERLY PRE-FRONTAL WIND.
CLOUD COVER WILL BE MORE WIDESPREAD WEST OF THE MOUNTAINS NEAR THE
FRONTAL ZONE...AND SOME BREAKS ARE POSSIBLE AS MORNING STRATUS BURNS
OFF AND HIGH CLOUD ABATE. HIGHS EACH DAY SHOULD REACH THE UPPER 60S
TO MID 70S...WITH FRIDAY BEING THE WARMEST DAY WHEN SOME EASTERN
COUNTIES COULD PUSH 80.
THE COLD FRONT AND ASSOCIATED MAINLY ANAFRONTAL PRECIP WILL MOVE
INTO CENTRAL NC LATE FRIDAY NIGHT AND EARLY SATURDAY. MODELS ARE IN
DECENT AGREEMENT ON THE TIMING OF THE FROPA...THOUGH THE 00Z ECMWF
IS A LITTLE SLOWER...AND CONFIDENCE IN THE EXACT TIMING OF THE FRONT
STILL REMAINS MEDIUM. THE SURFACE FRONT IS FORECAST TO PUSH SOUTH
OF THE NC/SC BORDER BY SATURDAY EVENING...BUT WITH THE 850MB FLOW
REMAINING OUT OF THE SOUTHWEST AND A 1030MB HIGH PRESSURE BUILDING
OVER NEW ENGLAND...A COLD AIR DAMMING EVENT SHOULD BEGIN TO QUICKLY
EVOLVE SATURDAY NIGHT INTO SUNDAY. THIS WILL BE ACCENTUATED BY AN
UPPER TROUGH DIGGING THROUGH THE CENTRAL US AND A SURFACE LOW MOVING
ACROSS THE MIDWEST AND GREAT LAKES ON SUNDAY. MUCH COLDER TEMPS
FALLING THROUGH THE 40S ON SATURDAY WILL BOTTOM OUT IN THE LOW TO
MID 30S SATURDAY NIGHT AND LIKELY HOLD IN THE 30S ON SUNDAY. AS THE
SURFACE HIGH...WHICH SHOULD BE PROGRESSIVE...MOVES OVER THE
NORTHEAST US...1000-850MB THICKNESSES MAY HOVER AROUND 1300M AND THE
WETBULB FREEZING LINE MAY MEANDER AROUND THE NORTHWEST PIEDMONT
SUNDAY MORNING. THIS WILL NEED TO BE MONITORED WITH SUBSEQUENT MODEL
RUNS...BUT OVERALL CONDITIONS DONT LOOK FAVORABLE FOR MORE THAN
BRIEF FREEZING RAIN.
ON THE HEELS OF THE AFOREMENTIONED SURFACE LOW....A COLD FRONT WILL
SWEEP ACROSS THE AREA MONDAY AND THE WEATHER SHOULD IMPROVE FOR THE
MIDDLE OF NEXT WEEK.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 705 AM TUESDAY...
SUB-VFR CONDITIONS ARE EXPECTED TO DEVELOP AT CENTRAL NC TAF SITES
DURING THIS 24 HR PERIOD. THE CURRENT VFR CONDITIONS WILL PERSIST
UNTIL AROUND 16Z (INT/GSO) TO 19Z (RDU/FAY) TO 21Z (RWI)... WHEN
CIGS ARE LIKELY TO DROP TO MVFR AS THE WARM FRONTAL ZONE APPROACHES
FROM THE SW AND MOISTURE SURGES TO THE NE UP AND OVER THE FRONTAL
ZONE. MVFR CIGS/VSBY SHOULD DOMINATE AT INT/GSO THROUGH 00Z WED...
THEN CIGS AT ALL SITES ARE LIKELY TO RISE BACK UP TO VFR FOR A FEW
HOURS BETWEEN 01Z AND 07Z. AFTER 07Z... ANOTHER SURGE IN LOW LEVEL
MOISTURE WILL CAUSE CIGS TO DROP BACK DOWN TO MVFR THEN TO IFR AT
ALL SITES AFTER 09Z... WITH MVFR TO IFR VSBYS. WINDS WILL BECOME
SWRLY TODAY AT SPEEDS UNDER 8 KTS.
LOOKING BEYOND 12Z WED... SUB-VFR CONDITIONS ARE EXPECTED TO
DOMINATE AT ALL SITES WED INTO THU WITH LOW MVFR-IFR CIGS AND SOME
MAINLY NIGHTTIME/MORNING MVFR FOG WITHIN A MOIST FLOW FROM THE SW.
THESE POOR AVIATION CONDITIONS MAY LAST THROUGH FRI INTO SAT AS WELL
AS A COLD FRONT MOVES SLOWLY INTO THE AREA FROM THE WNW... BRINGING
INCREASING RAIN CHANCES. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
308 AM EST TUE DEC 3 2013
.SYNOPSIS...COASTAL LOW PRESSURE WILL MOVE NORTHEAST AWAY FROM NORTH
CAROLINA THIS MORNING. WEAK HIGH PRESSURE WILL BUILD OVER THE AREA
TODAY AND TONIGHT...THEN SHIFT OFFSHORE WEDNESDAY AS A WARM FRONT
APPROACHES FROM THE SOUTH.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 235 AM TUESDAY...
TODAY WILL MARK THE START OF A PERIOD OF VERY LITTLE SUNSHINE. THE
LATEST SURFACE ANALYSIS SHOWS THE LOW OFF THE NRN NC OUTER BANKS
(ALONG THE OLD FRONT) HEADING ENE AWAY FROM OUR AREA (PUSHED BY THE
BAGGY MID LEVEL TROUGH NOW CROSSING THE AREA)... WHILE WEAK NARROW
HIGH PRESSURE SLIDES IN FROM THE WEST. THIS SURFACE RIDGE WILL BE
PROGRESSIVE... MOVING TO OUR EAST THIS AFTERNOON AS A LOW LEVEL WARM
FRONTAL ZONE (NOW STRETCHING ACROSS E TN THROUGH GA) HEADS SLOWLY NE
TOWARD CENTRAL NC. PATCHY LIGHT RAIN OVER AL/GA (FUELED IN PART BY
LOW LEVEL MOIST UPGLIDE AND WEAK MID LEVEL DPVA) IS MOVING EASTWARD
INTO SC AND SW NC... AND THE LATEST HRRR RUNS BRING THIS INTO OUR
FAR SW CWA EARLY THIS MORNING BEFORE IT DISSIPATES... SUPPORTING THE
IDEA THAT IT WILL ENCOUNTER ENOUGH LOW LEVEL DRY AIR IN PLACE TO BE
OF LITTLE CONSEQUENCE. WILL RETAIN A LOW CHANCE OF A SPRINKLE IN THE
SW THROUGH JUST PAST DAYBREAK. LOW LEVEL MOISTURE SHOULD CONTINUE TO
INCREASE FROM SW TO NE ACROSS CENTRAL NC THROUGH TODAY... WITH NE
SECTIONS SEEING THE MOST SUNSHINE (ALTHOUGH THIS TOO SHOULD BE
FILTERED) AND THE WEST SEEING VERY LITTLE SUN AS THE LOW LEVEL MOIST
UPGLIDE AT 290-300K RAMPS UP AND DEEPENS EARLY. MODELS DEPICT A VERY
WEAK MID LEVEL WAVE TRACKING FROM THE CENTRAL PLAINS THROUGH THE
MIDATLANTIC AREA TONIGHT... AND THE INCREASING MOISTURE COMBINED
WITH THIS WEAK LIFT ALOFT AND ALSO-WEAK LOWER-LEVEL LIFT WITH THE
APPROACHING WARM FRONT (EXPECTED TO PUSH THROUGH SC TOWARD THE NC
BORDER BY MIDNIGHT AND INTO FAR SRN AND SE NC OVERNIGHT) INCLUDING
WEAK 850 MB MASS CONVERGENCE WARRANTS A CHANCE OF LIGHT RAIN OVER
THE WRN AND EXTREME SRN CWA STARTING LATE THIS AFTERNOON GOING INTO
THIS EVENING. EXPECT LOW CHANCES TO THEN SPREAD NORTHWARD THROUGH NC
OVERNIGHT... BUT THE ANTECEDENT DRIER AIR HERE AND WEAK NATURE OF
THE ASCENT SHOULD GREATLY LIMIT COVERAGE AND AMOUNTS FARTHER NORTH.
THIS POP SCENARIO IS SUPPORTED BY THE SREF AND LATEST HI-RES WRF
RUNS. THE COOLEST TEMPS ACROSS THE AREA TODAY SHOULD BE IN THE SW
WHERE CLOUDS WILL BE THICKEST AND MOST PERSISTENT. THICKNESSES STILL
A BIT BELOW NORMAL FAVOR BELOW-NORMAL HIGHS OF 57-62. MILD LOWS OF
43-50... INCLUDING A SMALL UPWARD BUMP IN THE SOUTHERN CWA WITH
THICK CLOUDS AND THE NEARING WARM FRONT. -GIH
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 305 AM TUESDAY...
THE LOW LEVEL WARM FRONT IS EXPECTED TO CONTINUE ITS SLOW NORTHWARD
PROGRESSION THROUGH NC... ALTHOUGH THE MODELS SUGGEST THAT WHILE THE
925-850 MB FRONT SHOULD PROGRESS TO OUR NORTH... THE SURFACE WARM
FRONTAL ZONE MAY NOT QUITE GET ALL OF THE WAY THROUGH OUR CWA AS A
POCKET OF WEAKLY STABLE AIR MAY LINGER OVER THE NW PIEDMONT. WITHIN
THE DEEP SW FLOW... HIGH PW AIR WILL CONTINUE TO FUNNEL INTO
CENTRAL/ERN NC WITH VALUES AT OR OVER 1 INCH... NEAR OR EXCEEDING
200% OF NORMAL... WITH STEADY MOIST ISENTROPIC UPGLIDE OVER THE
AREA... PARTICULARLY WED MORNING... DECREASING AS THE WARM FRONT
JUST ALOFT SHIFTS TO OUR NORTH WITH UPGLIDE BECOMING WEAKER AND MORE
SHALLOW. THE EARLIER FORECAST SHOWS THIS TREND FAIRLY WELL... WITH
SLIGHT CHANCE POPS AND LOWER AMOUNTS IN THE NW WITH CHANCE POPS AND
A BIT MORE OVER THE SE CWA. WITH DECENT AGREEMENT ON THIS PATTERN
AMONGST THE MOST RECENT MODELS RUNS... WILL RETAIN THIS
CONFIGURATION... FOCUSING THE HIGHER (BUT STILL LESS THAN A 40%
CHANCE) POPS IN THE SE IN THE MORNING BEFORE TAPERING THEM OFF IN
THE AFTERNOON WITH THE DEPARTURE OF THE BETTER (YET STILL MODEST)
FORCING FOR ASCENT AND A BRIEF DIP IN THE PRECIP WATER. THE FLAT
FLOW ALOFT THAT IS GENTLY ANTICYCLONIC AND THE FOCUS OF THE WEAK
FORCING CONFINED TO THE LOWER ALTITUDES WILL LIMIT OVERALL PRECIP
TOTALS. EXPECT IT TO REMAIN MOSTLY CLOUDY TO CLOUDY... ESPECIALLY
OVERNIGHT AS ANOTHER SURGE IN VERY HIGH PW SPREADS IN FROM THE SW.
HIGHS FROM NEAR 60 NW (WHERE THE SLIGHTLY COOLER AND MORE STABLE AIR
WILL HOLD ON LONGER INTO WED) TO AROUND 70 SE (THANKS TO THICKNESSES
CLIMBING WELL ABOVE NORMAL). MILD LOWS 53-58. -GIH
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 250 AM MONDAY...
AN AMPLIFIED LONGWAVE PATTERN IN THE MEDIUM RANGE WILL FEATURE A
TROUGH OVER THE WESTERN US AND A RIDGE OVER THE WESTERN
ATLANTIC...WHICH WILL LEAD TO SPEEDY SOUTHWESTERLY FLOW ALOFT
BETWEEN THE TWO AND ACTIVE WESTERN OVER THE EASTERN US. AHEAD OF A
SLOWLY EVOLVING COLD FRONT OVER THE MIDWEST...LOW LEVEL THICKNESSES
OVER CENTRAL NC ARE FORECAST TO REACH AROUND 1375M THURSDAY AND
1385M ON FRIDAY...AIDED BY A STEADY SOUTHWESTERLY PRE-FRONTAL WIND.
CLOUD COVER WILL BE MORE WIDESPREAD WEST OF THE MOUNTAINS NEAR THE
FRONTAL ZONE...AND SOME BREAKS ARE POSSIBLE AS MORNING STRATUS BURNS
OFF AND HIGH CLOUD ABATE. HIGHS EACH DAY SHOULD REACH THE UPPER 60S
TO MID 70S...WITH FRIDAY BEING THE WARMEST DAY WHEN SOME EASTERN
COUNTIES COULD PUSH 80.
THE COLD FRONT AND ASSOCIATED MAINLY ANAFRONTAL PRECIP WILL MOVE
INTO CENTRAL NC LATE FRIDAY NIGHT AND EARLY SATURDAY. MODELS ARE IN
DECENT AGREEMENT ON THE TIMING OF THE FROPA...THOUGH THE 00Z ECMWF
IS A LITTLE SLOWER...AND CONFIDENCE IN THE EXACT TIMING OF THE FRONT
STILL REMAINS MEDIUM. THE SURFACE FRONT IS FORECAST TO PUSH SOUTH
OF THE NC/SC BORDER BY SATURDAY EVENING...BUT WITH THE 850MB FLOW
REMAINING OUT OF THE SOUTHWEST AND A 1030MB HIGH PRESSURE BUILDING
OVER NEW ENGLAND...A COLD AIR DAMMING EVENT SHOULD BEGIN TO QUICKLY
EVOLVE SATURDAY NIGHT INTO SUNDAY. THIS WILL BE ACCENTUATED BY AN
UPPER TROUGH DIGGING THROUGH THE CENTRAL US AND A SURFACE LOW MOVING
ACROSS THE MIDWEST AND GREAT LAKES ON SUNDAY. MUCH COLDER TEMPS
FALLING THROUGH THE 40S ON SATURDAY WILL BOTTOM OUT IN THE LOW TO
MID 30S SATURDAY NIGHT AND LIKELY HOLD IN THE 30S ON SUNDAY. AS THE
SURFACE HIGH...WHICH SHOULD BE PROGRESSIVE...MOVES OVER THE
NORTHEAST US...1000-850MB THICKNESSES MAY HOVER AROUND 1300M AND THE
WETBULB FREEZING LINE MAY MEANDER AROUND THE NORTHWEST PIEDMONT
SUNDAY MORNING. THIS WILL NEED TO BE MONITORED WITH SUBSEQUENT MODEL
RUNS...BUT OVERALL CONDITIONS DONT LOOK FAVORABLE FOR MORE THAN
BRIEF FREEZING RAIN.
ON THE HEELS OF THE AFOREMENTIONED SURFACE LOW....A COLD FRONT WILL
SWEEP ACROSS THE AREA MONDAY AND THE WEATHER SHOULD IMPROVE FOR THE
MIDDLE OF NEXT WEEK.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 100 AM TUESDAY...
SUB-VFR CONDITIONS ARE EXPECTED TO DEVELOP AT CENTRAL NC TAF SITES
DURING THIS 24 HR PERIOD... BUT THE TIMING AND HAZARDS WILL DIFFER
AT EACH LOCATION. AT INT/GSO... VFR CONDITIONS WILL PERSIST UNTIL
AROUND 17Z WHEN CIGS ARE LIKELY TO DROP TO MVFR AS THE WARM FRONTAL
ZONE APPROACHES FROM THE SW. MVFR CIGS/VSBY SHOULD DOMINATE AT
INT/GSO THROUGH 06Z WED. AT FAY... CIGS WILL STAY VFR THIS MORNING
BUT MVFR VSBYS IN FOG ARE EXPECTED 06Z-13Z WITH BRIEF IFR VSBYS
POSSIBLE. CIGS SHOULD DROP TO MVFR AFTER 18Z... THEN IMPROVE BACK UP
TO VFR AFTER 23Z. AT RDU/RWI... BRIEF MVFR VSBYS IN FOG ARE POSSIBLE
THROUGH 13Z THIS MORNING BUT OTHERWISE VFR CONDITIONS SHOULD STILL
DOMINATE THROUGH MIDDAY. CIGS MAY DROP TO MVFR AFTER 19Z BEFORE
RISING BACK TO VFR AFTER 23Z. WINDS WILL STAY LIGHT/VARIABLE THIS
MORNING THEN BECOME PREDOMINANTLY FROM THE SW OR SOUTH UNDER 8 KTS.
LOOKING BEYOND 06Z WED... SUB-VFR CONDITIONS ARE EXPECTED TO
DOMINATE AT ALL SITES FOR WED INTO THU WITH LOW CIGS AND SOME MAINLY
NIGHTTIME/MORNING FOG WITHIN A MOIST FLOW FROM THE SW. THESE POOR
AVIATION CONDITIONS MAY LAST THROUGH FRI INTO SAT AS WELL AS A COLD
FRONT MOVES SLOWLY INTO THE AREA FROM THE WNW... BRINGING INCREASING
RAIN CHANCES. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
250 AM EST TUE DEC 3 2013
.SYNOPSIS...COASTAL LOW PRESSURE WILL MOVE NORTHEAST AWAY FROM NORTH
CAROLINA THIS MORNING. WEAK HIGH PRESSURE WILL BUILD OVER THE AREA
TODAY AND TONIGHT...THEN SHIFT OFFSHORE WEDNESDAY AS A WARM FRONT
APPROACHES FROM THE SOUTH.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 235 AM TUESDAY...
TODAY WILL MARK THE START OF A PERIOD OF VERY LITTLE SUNSHINE. THE
LATEST SURFACE ANALYSIS SHOWS THE LOW OFF THE NRN NC OUTER BANKS
(ALONG THE OLD FRONT) HEADING ENE AWAY FROM OUR AREA (PUSHED BY THE
BAGGY MID LEVEL TROUGH NOW CROSSING THE AREA)... WHILE WEAK NARROW
HIGH PRESSURE SLIDES IN FROM THE WEST. THIS SURFACE RIDGE WILL BE
PROGRESSIVE... MOVING TO OUR EAST THIS AFTERNOON AS A LOW LEVEL WARM
FRONTAL ZONE (NOW STRETCHING ACROSS E TN THROUGH GA) HEADS SLOWLY NE
TOWARD CENTRAL NC. PATCHY LIGHT RAIN OVER AL/GA (FUELED IN PART BY
LOW LEVEL MOIST UPGLIDE AND WEAK MID LEVEL DPVA) IS MOVING EASTWARD
INTO SC AND SW NC... AND THE LATEST HRRR RUNS BRING THIS INTO OUR
FAR SW CWA EARLY THIS MORNING BEFORE IT DISSIPATES... SUPPORTING THE
IDEA THAT IT WILL ENCOUNTER ENOUGH LOW LEVEL DRY AIR IN PLACE TO BE
OF LITTLE CONSEQUENCE. WILL RETAIN A LOW CHANCE OF A SPRINKLE IN THE
SW THROUGH JUST PAST DAYBREAK. LOW LEVEL MOISTURE SHOULD CONTINUE TO
INCREASE FROM SW TO NE ACROSS CENTRAL NC THROUGH TODAY... WITH NE
SECTIONS SEEING THE MOST SUNSHINE (ALTHOUGH THIS TOO SHOULD BE
FILTERED) AND THE WEST SEEING VERY LITTLE SUN AS THE LOW LEVEL MOIST
UPGLIDE AT 290-300K RAMPS UP AND DEEPENS EARLY. MODELS DEPICT A VERY
WEAK MID LEVEL WAVE TRACKING FROM THE CENTRAL PLAINS THROUGH THE
MIDATLANTIC AREA TONIGHT... AND THE INCREASING MOISTURE COMBINED
WITH THIS WEAK LIFT ALOFT AND ALSO-WEAK LOWER-LEVEL LIFT WITH THE
APPROACHING WARM FRONT (EXPECTED TO PUSH THROUGH SC TOWARD THE NC
BORDER BY MIDNIGHT AND INTO FAR SRN AND SE NC OVERNIGHT) INCLUDING
WEAK 850 MB MASS CONVERGENCE WARRANTS A CHANCE OF LIGHT RAIN OVER
THE WRN AND EXTREME SRN CWA STARTING LATE THIS AFTERNOON GOING INTO
THIS EVENING. EXPECT LOW CHANCES TO THEN SPREAD NORTHWARD THROUGH NC
OVERNIGHT... BUT THE ANTECEDENT DRIER AIR HERE AND WEAK NATURE OF
THE ASCENT SHOULD GREATLY LIMIT COVERAGE AND AMOUNTS FARTHER NORTH.
THIS POP SCENARIO IS SUPPORTED BY THE SREF AND LATEST HI-RES WRF
RUNS. THE COOLEST TEMPS ACROSS THE AREA TODAY SHOULD BE IN THE SW
WHERE CLOUDS WILL BE THICKEST AND MOST PERSISTENT. THICKNESSES STILL
A BIT BELOW NORMAL FAVOR BELOW-NORMAL HIGHS OF 57-62. MILD LOWS OF
43-50... INCLUDING A SMALL UPWARD BUMP IN THE SOUTHERN CWA WITH
THICK CLOUDS AND THE NEARING WARM FRONT. -GIH
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 245 PM MONDAY...
TO BE UPDATED SHORTLY...
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 250 AM MONDAY...
AN AMPLIFIED LONGWAVE PATTERN IN THE MEDIUM RANGE WILL FEATURE A
TROUGH OVER THE WESTERN US AND A RIDGE OVER THE WESTERN
ATLANTIC...WHICH WILL LEAD TO SPEEDY SOUTHWESTERLY FLOW ALOFT
BETWEEN THE TWO AND ACTIVE WESTERN OVER THE EASTERN US. AHEAD OF A
SLOWLY EVOLVING COLD FRONT OVER THE MIDWEST...LOW LEVEL THICKNESSES
OVER CENTRAL NC ARE FORECAST TO REACH AROUND 1375M THURSDAY AND
1385M ON FRIDAY...AIDED BY A STEADY SOUTHWESTERLY PRE-FRONTAL WIND.
CLOUD COVER WILL BE MORE WIDESPREAD WEST OF THE MOUNTAINS NEAR THE
FRONTAL ZONE...AND SOME BREAKS ARE POSSIBLE AS MORNING STRATUS BURNS
OFF AND HIGH CLOUD ABATE. HIGHS EACH DAY SHOULD REACH THE UPPER 60S
TO MID 70S...WITH FRIDAY BEING THE WARMEST DAY WHEN SOME EASTERN
COUNTIES COULD PUSH 80.
THE COLD FRONT AND ASSOCIATED MAINLY ANAFRONTAL PRECIP WILL MOVE
INTO CENTRAL NC LATE FRIDAY NIGHT AND EARLY SATURDAY. MODELS ARE IN
DECENT AGREEMENT ON THE TIMING OF THE FROPA...THOUGH THE 00Z ECMWF
IS A LITTLE SLOWER...AND CONFIDENCE IN THE EXACT TIMING OF THE FRONT
STILL REMAINS MEDIUM. THE SURFACE FRONT IS FORECAST TO PUSH SOUTH
OF THE NC/SC BORDER BY SATURDAY EVENING...BUT WITH THE 850MB FLOW
REMAINING OUT OF THE SOUTHWEST AND A 1030MB HIGH PRESSURE BUILDING
OVER NEW ENGLAND...A COLD AIR DAMMING EVENT SHOULD BEGIN TO QUICKLY
EVOLVE SATURDAY NIGHT INTO SUNDAY. THIS WILL BE ACCENTUATED BY AN
UPPER TROUGH DIGGING THROUGH THE CENTRAL US AND A SURFACE LOW MOVING
ACROSS THE MIDWEST AND GREAT LAKES ON SUNDAY. MUCH COLDER TEMPS
FALLING THROUGH THE 40S ON SATURDAY WILL BOTTOM OUT IN THE LOW TO
MID 30S SATURDAY NIGHT AND LIKELY HOLD IN THE 30S ON SUNDAY. AS THE
SURFACE HIGH...WHICH SHOULD BE PROGRESSIVE...MOVES OVER THE
NORTHEAST US...1000-850MB THICKNESSES MAY HOVER AROUND 1300M AND THE
WETBULB FREEZING LINE MAY MEANDER AROUND THE NORTHWEST PIEDMONT
SUNDAY MORNING. THIS WILL NEED TO BE MONITORED WITH SUBSEQUENT MODEL
RUNS...BUT OVERALL CONDITIONS DONT LOOK FAVORABLE FOR MORE THAN
BRIEF FREEZING RAIN.
ON THE HEELS OF THE AFOREMENTIONED SURFACE LOW....A COLD FRONT WILL
SWEEP ACROSS THE AREA MONDAY AND THE WEATHER SHOULD IMPROVE FOR THE
MIDDLE OF NEXT WEEK.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 100 AM TUESDAY...
SUB-VFR CONDITIONS ARE EXPECTED TO DEVELOP AT CENTRAL NC TAF SITES
DURING THIS 24 HR PERIOD... BUT THE TIMING AND HAZARDS WILL DIFFER
AT EACH LOCATION. AT INT/GSO... VFR CONDITIONS WILL PERSIST UNTIL
AROUND 17Z WHEN CIGS ARE LIKELY TO DROP TO MVFR AS THE WARM FRONTAL
ZONE APPROACHES FROM THE SW. MVFR CIGS/VSBY SHOULD DOMINATE AT
INT/GSO THROUGH 06Z WED. AT FAY... CIGS WILL STAY VFR THIS MORNING
BUT MVFR VSBYS IN FOG ARE EXPECTED 06Z-13Z WITH BRIEF IFR VSBYS
POSSIBLE. CIGS SHOULD DROP TO MVFR AFTER 18Z... THEN IMPROVE BACK UP
TO VFR AFTER 23Z. AT RDU/RWI... BRIEF MVFR VSBYS IN FOG ARE POSSIBLE
THROUGH 13Z THIS MORNING BUT OTHERWISE VFR CONDITIONS SHOULD STILL
DOMINATE THROUGH MIDDAY. CIGS MAY DROP TO MVFR AFTER 19Z BEFORE
RISING BACK TO VFR AFTER 23Z. WINDS WILL STAY LIGHT/VARIABLE THIS
MORNING THEN BECOME PREDOMINANTLY FROM THE SW OR SOUTH UNDER 8 KTS.
LOOKING BEYOND 06Z WED... SUB-VFR CONDITIONS ARE EXPECTED TO
DOMINATE AT ALL SITES FOR WED INTO THU WITH LOW CIGS AND SOME MAINLY
NIGHTTIME/MORNING FOG WITHIN A MOIST FLOW FROM THE SW. THESE POOR
AVIATION CONDITIONS MAY LAST THROUGH FRI INTO SAT AS WELL AS A COLD
FRONT MOVES SLOWLY INTO THE AREA FROM THE WNW... BRINGING INCREASING
RAIN CHANCES. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...VINCENT
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
235 AM EST TUE DEC 3 2013
.SYNOPSIS...COASTAL LOW PRESSURE WILL MOVE NORTHEAST AWAY FROM NORTH
CAROLINA THIS MORNING. WEAK HIGH PRESSURE WILL BUILD OVER THE AREA
TODAY AND TONIGHT...THEN SHIFT OFFSHORE WEDNESDAY AS A WARM FRONT
APPROACHES FROM THE SOUTH.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 235 AM TUESDAY...
TODAY WILL MARK THE START OF A PERIOD OF VERY LITTLE SUNSHINE. THE
LATEST SURFACE ANALYSIS SHOWS THE LOW OFF THE NRN NC OUTER BANKS
(ALONG THE OLD FRONT) HEADING ENE AWAY FROM OUR AREA (PUSHED BY THE
BAGGY MID LEVEL TROUGH NOW CROSSING THE AREA)... WHILE WEAK NARROW
HIGH PRESSURE SLIDES IN FROM THE WEST. THIS SURFACE RIDGE WILL BE
PROGRESSIVE... MOVING TO OUR EAST THIS AFTERNOON AS A LOW LEVEL WARM
FRONTAL ZONE (NOW STRETCHING ACROSS E TN THROUGH GA) HEADS SLOWLY NE
TOWARD CENTRAL NC. PATCHY LIGHT RAIN OVER AL/GA (FUELED IN PART BY
LOW LEVEL MOIST UPGLIDE AND WEAK MID LEVEL DPVA) IS MOVING EASTWARD
INTO SC AND SW NC... AND THE LATEST HRRR RUNS BRING THIS INTO OUR
FAR SW CWA EARLY THIS MORNING BEFORE IT DISSIPATES... SUPPORTING THE
IDEA THAT IT WILL ENCOUNTER ENOUGH LOW LEVEL DRY AIR IN PLACE TO BE
OF LITTLE CONSEQUENCE. WILL RETAIN A LOW CHANCE OF A SPRINKLE IN THE
SW THROUGH JUST PAST DAYBREAK. LOW LEVEL MOISTURE SHOULD CONTINUE TO
INCREASE FROM SW TO NE ACROSS CENTRAL NC THROUGH TODAY... WITH NE
SECTIONS SEEING THE MOST SUNSHINE (ALTHOUGH THIS TOO SHOULD BE
FILTERED) AND THE WEST SEEING VERY LITTLE SUN AS THE LOW LEVEL MOIST
UPGLIDE AT 290-300K RAMPS UP AND DEEPENS EARLY. MODELS DEPICT A VERY
WEAK MID LEVEL WAVE TRACKING FROM THE CENTRAL PLAINS THROUGH THE
MIDATLANTIC AREA TONIGHT... AND THE INCREASING MOISTURE COMBINED
WITH THIS WEAK LIFT ALOFT AND ALSO-WEAK LOWER-LEVEL LIFT WITH THE
APPROACHING WARM FRONT (EXPECTED TO PUSH THROUGH SC TOWARD THE NC
BORDER BY MIDNIGHT AND INTO FAR SRN AND SE NC OVERNIGHT) INCLUDING
WEAK 850 MB MASS CONVERGENCE WARRANTS A CHANCE OF LIGHT RAIN OVER
THE WRN AND EXTREME SRN CWA STARTING LATE THIS AFTERNOON GOING INTO
THIS EVENING. EXPECT LOW CHANCES TO THEN SPREAD NORTHWARD THROUGH NC
OVERNIGHT... BUT THE ANTECEDENT DRIER AIR HERE AND WEAK NATURE OF
THE ASCENT SHOULD GREATLY LIMIT COVERAGE AND AMOUNTS FARTHER NORTH.
THIS POP SCENARIO IS SUPPORTED BY THE SREF AND LATEST HI-RES WRF
RUNS. THE COOLEST TEMPS ACROSS THE AREA TODAY SHOULD BE IN THE SW
WHERE CLOUDS WILL BE THICKEST AND MOST PERSISTENT. THICKNESSES STILL
A BIT BELOW NORMAL FAVOR BELOW-NORMAL HIGHS OF 57-62. MILD LOWS OF
43-50... INCLUDING A SMALL UPWARD BUMP IN THE SOUTHERN CWA WITH
THICK CLOUDS AND THE NEARING WARM FRONT. -GIH
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 245 PM MONDAY...
WSW FLOW ALOFT ON THE WESTERN PERIPHERY OF AN UPPER LEVEL RIDGE
BUILDING ALONG/JUST OFFSHORE THE EAST COAST WILL GIVE WAY TO
STRENGTHENING SW FLOW ALOFT ACROSS THE CAROLINAS BY FRIDAY AS AN
UPPER LEVEL TROUGH DEEPENS OVER THE ROCKIES/CENTRAL CONUS. IN THE
LOWER LEVELS...A PERSISTENT SOUTHERLY RETURN FLOW /WARM ADVECTION
REGIME/ WILL PREVAIL ON THE WESTERN PERIPHERY OF OFFSHORE HIGH
PRESSURE...WITH INCREASING MOISTURE ACROSS THE CAROLINAS IN THE WED-
FRI TIME FRAME. DESPITE INCREASING CLOUD COVER DOWNSTREAM OF PRECIP
EXPECTED TO DEVELOP ALONG A STRENGTHENING FRONTAL ZONE OVER THE
LOWER MS RIVER VALLEY AND TN/OH VALLEY ON THU/FRI...THERE IS HIGH
CONFIDENCE THAT STRONG WARM ADVECTION WILL RESULT IN A WARMING TREND
EACH DAY...WITH TEMPS IN THE LOWER/MID 70S (ESP. EAST OF HWY 1) BY
FRIDAY.
CONFIDENCE IN PRECIPITATION CHANCES REMAINS LOWER THAN AVERAGE. THE
LATEST MODEL GUIDANCE SUGGESTS A CHANCE OF LIGHT RAIN WED MORNING
THROUGH EARLY WED AFTERNOON IN ASSOC/W INCREASING MOISTURE AND THE
INITIAL SURGE OF STRONG LOW/MID-LEVEL WARM ADVECTION...THOUGH
PRECISE COVERAGE AND TIMING REMAIN DIFFICULT TO ASCERTAIN AT THIS
RANGE. DUE TO INCREASED CLOUD COVER AND A CHANCE OF RAIN...HIGH
TEMPS ON WED COULD RANGE FROM THE UPPER 50S TO UPPER 60S. EXPECT
LITTLE CHANCE FOR PRECIPITATION WED NIGHT THROUGH THE DAYTIME HOURS
ON FRIDAY GIVEN VERY LITTLE FORCING (ASIDE FROM TRANSIENT SMALL
AMPLITUDE WAVES IN SW FLOW ALOFT) AS THE AFOREMENTIONED FRONTAL ZONE
SLOWLY APPROACHES THE MOUNTAINS FROM THE WEST. WILL INDICATE LARGELY
DRY CONDITIONS WED NIGHT THROUGH FRIDAY. HIGHS WILL PRIMARILY DEPEND
ON CLOUD COVER THU/FRI...RANGING FROM THE MID/UPPER 60S NW (MORE
CLOUD COVER) TO LOWER 70S SE ON THU...AND UPPER 60S NW TO MID 70S SE
ON FRI. -VINCENT
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
AS OF 345 PM MONDAY...
FRI NIGHT THROUGH SAT: DESPITE BEING 120+ HOURS OUT...FORECAST
CONFIDENCE REMAINS HIGH THAT A STRONG COLD FRONT WILL PROGRESS
THROUGH CENTRAL NC FRIDAY NIGHT AND SATURDAY MORNING...THOUGH THE
PRECISE TIMING IS STILL DIFFICULT TO ASCERTAIN THIS FAR OUT IN THE
FCST AND WILL HIGHLY AFFECT BOTH LOW TEMPS FRI NIGHT AND HIGHS ON
SAT. PRECIP AMOUNTS ALONG AND BEHIND THE COLD FRONT APPEAR GENERALLY
ON THE LOWER END OF THE SPECTRUM. WITHOUT MUCH IN THE WAY OF UPPER
LEVEL FORCING AND UNIDIRECTIONAL SW FLOW ALOFT...FORCING WILL
PRIMARILY BE CONFINED TO LOW-LEVEL CONVERGENCE ALONG THE SFC FRONT
AND WARM ADVECTION OVER/BEHIND THE SURFACE FRONT PROGRESSING E/SE
THROUGH THE CAROLINAS...WITH THE 925-850 MB TROUGH LAGGING BEHIND.
WILL MAINTAIN PRECIP CHANCES ~60% LATE FRI NIGHT THROUGH EARLY SAT
AFTERNOON. THEREAFTER...PRECIP CHANCES MAY LARGELY END SAT AFT/EVE
ASIDE FROM A POTENTIAL FOR PATCHY DRIZZLE. TEMPS WILL FALL FROM THE
60S LATE FRI EVENING TO THE 40S FROM NW-SE SATURDAY MORNING THROUGH
EARLY SAT AFTERNOON...LIKELY CONTINUING TO FALL MID/LATE SAT
AFTERNOON AS STRONG/COLD HIGH PRESSURE OVER THE UPPER MIDWEST
PROGRESSES EAST INTO THE GREAT LAKES RESULTING IN FURTHER PRESSURE
RISES /COLD ADVECTION/ LATE SAT INTO SAT NIGHT...WITH A PRONOUNCED
SFC RIDGE AXIS EXTENDING SOUTHWARD INTO THE CAROLINAS.
SATURDAY NIGHT THROUGH MONDAY: AN UPPER LEVEL TROUGH DIGGING INTO
THE 4-CORNERS REGION SAT IS PROGGED TO TRACK EAST INTO THE CENTRAL
PLAINS SAT NIGHT...AFFECTING THE LOW-LEVEL HEIGHT PATTERN
(BACKING/STRENGTHENING LOW-LEVEL FLOW) OVER THE SOUTHEAST CONUS AND
ENHANCING WARM ADVECTION /ISENTROPIC LIFT/ ATOP THE STRONG SFC RIDGE
AXIS /CAD WEDGE/ OVER THE CAROLINAS. AS A RESULT...AFTER A BRIEF
LULL SAT AFT/EVE LIGHT RAIN COULD RE-DEVELOP FROM SOUTH-NORTH SAT
NIGHT. LOWS SAT NIGHT WILL HIGHLY DEPEND ON THE PRECISE NATURE OF
THE COLD/DRY AIRMASS ADVECTING INTO THE REGION AND ANY POTENTIAL
EVAP COOLING ASSOC/W PRECIPITATION THAT MAY RE-DEVELOP...AND IT IS
POSSIBLE THAT PTYPE ISSUES (I.E. FZRA) COULD BE AN ISSUE IN THE NW
PIEDMONT. HOWEVER...AT THIS RANGE CONFIDENCE IS TOO LOW W/REGARD TO
THE SPECIFICS AND WILL MENTION ALL RAIN WITH LOWS IN THE MID 30S
(NW) TO UPPER 30S (SE). THE UPPER LEVEL WAVE IS EXPECTED TO
DEAMPLIFY AS IT TRACKS INTO THE TN VALLEY AND MID-ATLANTIC SUN AND
SUN NIGHT. EXPECT OVERCAST SKIES/RAIN AND NEAR STEADY TEMPS IN THE
30S TO PERHAPS 40S IN FAR SE COASTAL PLAIN ON SUNDAY IN ASSOC/W A
STRONG CAD WEDGE AND EVOLVING WEAK MILLER-B CYCLONE. FROM A PATTERN
RECOGNITION STANDPOINT...BASED ON THE LATEST GUIDANCE...FZRA AND
SOME POTENTIAL FOR ICE ACCUMULATION CANNOT BE RULED OUT IN THE NW
PIEDMONT ON SUNDAY...DEPENDING ON THE PRECISE NATURE/TIMING OF THE
AIRMASS ADVECTING INTO THE REGION FROM THE NORTH AND THE EVOLUTION
OF THE AFOREMENTIONED MILLER-B CYCLONE. DUE TO SIGNIFICANT
UNCERTAINTY AT THIS RANGE...WILL MENTION ONLY RAIN IN THE OFFICIAL
FORECAST. PRECIPITATION WILL END FROM W-E SUN NIGHT IN ASSOC/W A
COLD FRONTAL PASSAGE FROM THE WEST AS THE PRIMARY SFC CYCLONE
CONSOLIDATES ALONG THE MID-ATLANTIC COAST AND TRACKS NE AWAY FROM
THE REGION. -VINCENT
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 100 AM TUESDAY...
SUB-VFR CONDITIONS ARE EXPECTED TO DEVELOP AT CENTRAL NC TAF SITES
DURING THIS 24 HR PERIOD... BUT THE TIMING AND HAZARDS WILL DIFFER
AT EACH LOCATION. AT INT/GSO... VFR CONDITIONS WILL PERSIST UNTIL
AROUND 17Z WHEN CIGS ARE LIKELY TO DROP TO MVFR AS THE WARM FRONTAL
ZONE APPROACHES FROM THE SW. MVFR CIGS/VSBY SHOULD DOMINATE AT
INT/GSO THROUGH 06Z WED. AT FAY... CIGS WILL STAY VFR THIS MORNING
BUT MVFR VSBYS IN FOG ARE EXPECTED 06Z-13Z WITH BRIEF IFR VSBYS
POSSIBLE. CIGS SHOULD DROP TO MVFR AFTER 18Z... THEN IMPROVE BACK UP
TO VFR AFTER 23Z. AT RDU/RWI... BRIEF MVFR VSBYS IN FOG ARE POSSIBLE
THROUGH 13Z THIS MORNING BUT OTHERWISE VFR CONDITIONS SHOULD STILL
DOMINATE THROUGH MIDDAY. CIGS MAY DROP TO MVFR AFTER 19Z BEFORE
RISING BACK TO VFR AFTER 23Z. WINDS WILL STAY LIGHT/VARIABLE THIS
MORNING THEN BECOME PREDOMINANTLY FROM THE SW OR SOUTH UNDER 8 KTS.
LOOKING BEYOND 06Z WED... SUB-VFR CONDITIONS ARE EXPECTED TO
DOMINATE AT ALL SITES FOR WED INTO THU WITH LOW CIGS AND SOME MAINLY
NIGHTTIME/MORNING FOG WITHIN A MOIST FLOW FROM THE SW. THESE POOR
AVIATION CONDITIONS MAY LAST THROUGH FRI INTO SAT AS WELL AS A COLD
FRONT MOVES SLOWLY INTO THE AREA FROM THE WNW... BRINGING INCREASING
RAIN CHANCES. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...VINCENT
LONG TERM...VINCENT
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1134 PM CST MON DEC 2 2013
.UPDATE...
ISSUED AT 1134 PM CST MON DEC 2 2013
ONLY CHANGE FOR THE EARLY AM UPDATE WILL BE TO CUT BACK ON QPF FOR
12Z TO 18Z TIMEFRAME ABOUT 50 PER CENT AND 18Z TO 00Z TIME FRAME
ABOUT 20 PER CENT AS ONE THING THE MODELS ACTUALLY **ARE** IN
AGREEMENT WITH IS A LULL IN ACTIVITY THROUGH MUCH OF THE DAY
TOMORROW. DO SEE CLOUDY SKIES AND A VERY...VERY LIGHT SNOW (BUT
HIGH POP) SCENARIO...BUT THAT WILL NOT AMT TO MUCH IN TERMS OF
QPF. RERAN SNOW TOTALS FOR WAVE TWO AND THIS BRINGS US DOWN TO A
VERY LOW END WARNING OF SIX TO EIGHT INCHES ACROSS ALL BUT THE
NORTHERN TIER OF ZONES ALONG THE INTL BORDER...WHICH WOULD BE HIGH
END ADVISORY IN THE FOUR TO SIX RANGE. HOWEVER...MODELS STILL
DIFFERING QUITE A BIT AND PUSHING PRECIP FURTHER SOUTH. THIS
GRADIENT COULD BE EVEN TIGHTER WITH VERY LITTLE AT ALL ACROSS THE
FAR NORTH. STILL ENOUGH UNCERTAINTY WITH 00Z RUNS AND TIME TO
ASSESS 12Z RUNS TOMORROW BEFORE MAKING ANY FINAL DECISIONS ON
HEADLINES...BUT CAN EXPECT VERY LITTLE IMPACT THROUGH 18Z TOMORROW.
UPDATE ISSUED AT 927 PM CST MON DEC 2 2013
THE FOCUS FOR THE 10 PM UPDATE WILL BE THE ISSUANCE OF A WINTER
STORM WARNING FOR THE SOUTHEAST...MAINLY SOUTHERN BELTRAMI THROUGH
WADENA COUNTY AND EASTERN PORTIONS OF BECKER...CLEARWATER...AND
OTTER TAIL.
STORM TOTALS AT THE BEGINNING OF EVENING SHIFT WERE AROUND 5 TO 6
INCHES AND RADAR TRENDS AND THE LATEST RAP GUIDANCE INDICATED THE
EVENT SHOULD END AROUND 11 PM. HRRR WAS A BIT SLOWER...PULLING
PRECIP OUT AROUND 1 AM. HOWEVER...WITH RADAR COVERAGE EXTREMELY
POOR IN THIS AREA DUE TO DISTANCE/OVERSHOOTING ISSUES...HAVE HAD
TO MAKE A PLETHORA OF CALLS IN THE AREA. WE ARE NOW RECEIVING
REPORTS IN THE 6 TO 8 INCH RANGE WITH AN ISOLATED REPORT AROUND 9.
REPORTS FROM THE WADENA AREA INDICATE THE SNOW IS STILL COMING
DOWN AT A DECENT RATE OF AN INCH PER HOUR. AFTER COORDINATION WITH
DLH OFFICE...WILL BE ISSUING A WINTER STORM WARNING FOR THE AREA.
TOTAL ACCUMULATION MAY GET TO THE 8 TO 10 INCH RANGE WITH ISOLATED
AMOUNTS SLIGHTLY HIGHER. THE NAM IS INDICATING A NARROW BAND OF
INCREASED 280K ISENTROPIC LIFT OVER THE AREA. WARNING WILL BE IN
EFFECT UNTIL 12Z.
IT IS VERY IMPORTANT TO REALIZE THE WARNING IS PART OF THE FIRST
WAVE OF SNOW THAT HAS BEEN ADVERTISED...AND WILL BE FOLLOWED BY A
WINTER STORM WATCH FOR THE SECOND WAVE THAT WILL IMPACT THE AREA
FROM MID DAY TUESDAY THROUGH MUCH OF THE DAY WEDNESDAY. ONLY MINOR
UPDATES TO THE GRIDS FOR THE 2ND WAVE...ALTHOUGH HAVE EXPANDED THE
AREA OF LOWER POPS FOR THE LULL IN ACTIVITY EXPECTED ACROSS THE
SOUTH FOR THE REMAINDER OF TONIGHT THROUGH MID DAY TUESDAY.
UPDATE ISSUED AT 648 PM CST MON DEC 2 2013
FOCUS FOR EVENING UPDATE WILL BE TO EXTEND FAR SOUTHERN ZONES
(RANSOM/SARGENT THROUGH GRANT) WINTER WEATHER ADVISORY THROUGH 12Z
TO MATCH REST OF HEADLINES. AREA WAS SET TO EXPIRE AT
00Z...HOWEVER WEAK ECHOES MOVING INTO REGION AS WELL AS SOUNDINGS
INDICATING POSSIBILITY OF SOME FREEZING DRIZZLE...WOULD PREFER TO
EXTEND IN TIME WITH WEATHER OVER THE REGION CONTINUING. SNOWFALL
CONTINUES MAINLY ALONG AND NORTH OF I 94 CORRIDOR WITH SOME SITES
NOW REPORTING SIX INCHES (BJI AND PKD). CHECKING NOW TO SEE HOW
WIDESPREAD THE SIX INCH REPORTS ARE TO DETERMINE IF HEADLINES
SHOULD BE UPDATED. MORE DIFFICULT TO DETERMINE IN THIS AREA AS
RADAR OVERSHOOTS SNOW IN THE BJI AREA...SO MAINLY WILL GO OFF WEB
CAMS AND PUBLIC REPORTS. STAY TUNED FOR MORE INFO IN THIS REGION.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 321 PM CST MON DEC 2 2013
PRECIP TYPE...SNOW AMOUNTS AND WHAT TO DO WITH HEADLINES CONTINUE
TO BE THE PRIMARY FORECAST HEADACHES FOR THE PERIOD.
MAIN UPPER LOW IS STILL DIGGING INTO THE PAC NW THIS
AFTERNOON...WITH ONLY PARTIAL RAOB SAMPLING FOR THE INITIALIZATION
OF THE 12Z MODEL RUNS THIS MORNING. MODEL CONSISTENCY HAS
CONTINUED TO BE POOR EVEN IN THE FIRST 24 HOURS OF THE RUNS. SNOW
BAND FROM THE LEAD SHORTWAVE TODAY HAS BROUGHT 3 TO 6 INCHES OF
ACCUMULATION FROM WEST OF FARGO TO NEAR ALEX. HOWEVER...THE BAND
HAS BEEN WEAKENING AS IT MOVES NORTHEASTWARD. THINK THAT SNOW
ACCUMULATIONS NORTH OF THE I-94 CORRIDOR WILL BE FAIRLY LIGHT AND
MAY ONLY BE AN INCH OR TWO. HOWEVER...THERE IS STILL A LOT OF
SLICK ROADS AND SOME OF THE MODELS SOUNDINGS ACROSS THE SOUTHERN
COUNTIES SHOW THE POSSIBILITY OF SOME FREEZING DRIZZLE. WILL
CONTINUE TO KEEP THE WINTER WEATHER ADVISORY GOING OVERNIGHT.
FOR TOMORROW...THE MODELS SHOW THE FIRST UPPER SHORTWAVE EJECTING
NORTHEASTWARD INTO THE DAKOTAS TUESDAY WHILE THE NEXT SHORTWAVE
DIGS FURTHER SOUTH AND DOES NOT MOVE EASTWARD UNTIL MID WEEK.
THERE IS STILL DISAGREEMENT ON THE EXACT TRACK OF THE SFC
LOW. ALL START IT OFF AS AN INVERTED TROUGH OVER SOUTHERN
MN...WITH A DECENT PRECIP BAND OVER THE CWA AND WINDS STARTING TO
PICK UP. HOWEVER...WHEN THE MODELS CLOSE THE LOW OFF AND HOW FAR
WEST REMAINS IN QUESTION. THE ECMWF HAS TRENDED FARTHER SOUTH WITH
THE HEAVY SNOW BAND WITH EACH RUN...AND THE GFS AND 12Z NAM ALSO
SEEM TO BE FARTHER SOUTH...ALTHOUGH THE 18Z NAM HAS GONE BACK THE
OTHER DIRECTION. EVEN WITH THE FURTHER NORTH SOLUTION...THE CWA
WILL BE IN A LULL BETWEEN TODAYS LEAD SHORTWAVE AND THE NEXT VORT
MAX...SO CONDITIONS MAY NOT BE TOO BAD WHEN PEOPLE GET UP IN THE
MORNING. WITH THIS AND ALL THE UNCERTAINTY OF US EVEN GETTING 6
INCHES...WILL MAINTAIN THE WATCH AND HOLD OFF ON ANY UPGRADES FOR
NOW.
TUESDAYS SHORTWAVE WILL MOVE OFF INTO WI TUESDAY NIGHT...WITH SFC
LOW DEEPENING. THE PRESSURE GRADIENT WILL BE PICKING UP AS THE
ARCTIC HIGH DIGS INTO THE NORTHERN ROCKIES. WINDS WILL BE VERY
STRONG LATE TUESDAY INTO TUESDAY NIGHT...AND BLOWING AND DRIFTING
SNOW COULD BE A PROBLEM. WILL CONTINUE TO MAKE MENTION OF THIS IN
THE WSW AND GRIDS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 321 PM CST MON DEC 2 2013
WEDNESDAY...AN UPPER TROUGH WILL CONTINUE OVER THE ROCKIES...WITH
ANOTHER WEAK SHORTWAVE EJECTING INTO THE PLAINS. WILL CONTINUE TO
KEEP HIGH POPS GOING AND STRONG WINDS...AND THE WATCH WILL REMAIN
THROUGH THE PERIOD. THE SFC LOW WILL MOVE OFF TO THE EAST...WITH
THE ARCTIC AIR COMING IN BEHIND IT. TEMPS MAY NOT GET OUT OF THE
SINGLE DIGITS IN THE NORTHWESTERN COUNTIES AND WITH WINDS
CONTINUING THE CHILL FACTOR WILL BE BRUTAL.
FOR WEDNESDAY NIGHT INTO THURSDAY THERE ARE STILL ENOUGH MODEL
DIFFERENCES TO KEEP A LOT OF UNCERTAINTY IN THE FORECAST. THE 12Z
ECMWF STILL HAS A PRETTY DECENT PRESSURE GRADIENT OVER THE FA WHILE
THE 12Z GFS HAS MUCH LESS. FOR NOW WILL KEEP THINGS MIDDLE OF THE
ROAD WITH SOME GUSTINESS LINGERING WED NIGHT AND THEN DIMINISHING
THINGS ON THU. COLDER AIR WILL CONTINUE TO MOVE INTO THE FA WITH
TEMPS HINGING ON CLOUD COVER. RIGHT NOW IT APPEARS LIKE A GOOD
AMOUNT OF CLOUD COVER WILL HOLD OVER THE AREA KEEPING THE REALLY
COLD TEMPS AT BAY. HOWEVER DETERMINING CLOUD AMOUNTS WITH GOOD
ACCURACY THIS FAR OUT IS TOUGH.
BY THU NIGHT INTO MONDAY CLOUD TRENDS AND TEMPS WILL BE THE MAIN
ISSUE. MODELS SEEM TO LINGER SNOW SHOWERS IN THE NORTHEAST FA A LONG
TIME OR GENERALLY FROM THU NIGHT THRU SAT NIGHT. MEANWHILE 850MB
TEMPS DROP WELL INTO THE 20S BELOW ZERO. SFC HIGH PRESSURE WILL TRY
TO BUILD INTO THE FA BY SATURDAY BUT UNTIL THEN THE 12Z ECMWF KEEPS
SUSTAINED WIND SPEEDS ABOVE 10KTS. THEREFORE IT WILL BE HARD TO
REALIZE THE FULL POTENTIAL OF THE COLD AIR. THE HIGH PRESSURE SYSTEM
IS EXPECTED TO SLIDE TO THE EAST SAT NIGHT AS ANOTHER WEAKER SYSTEM
MOVES UP INTO THE FA FROM THE SOUTHWEST. THIS NEXT SYSTEM LOOKS
WEAKER SO SNOW AMOUNTS SHOULD STAY ON THE LIGHTER SIDE. THIS SYSTEM
WOULD ALSO SPREAD MORE CLOUD COVER INTO THE REGION WHICH WOULD
CONTINUE TO MODERATE THE FRIGID AIR OVER THE FA. HOWEVER COLD IS
COLD AND CLOUDS WOULD NOT MODERATE THINGS THAT MUCH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1134 PM CST MON DEC 2 2013
MOST SITES WILL BE IN MVFR RANGE THROUGH EARLY AFTN TUESDAY...WHEN
CIGS WILL GRADUALLY BEGIN SINKING AND NORTHERLY WINDS WILL BEGIN
TO INCREASE AS THE SYSTEM PULLS ACROSS THE PLAINS. HAVE DELAYED
SNOW AT SITES TILL MID TO LATE AFTN. BJI IS THE EXCEPTION...WHICH
COULD SEE SOME LIGHT SNOW AND IFR CIGS OVER THE NEXT 24 HRS AS
LOW LEVEL MOISTURE IS MORE ABUNDANT IN NORTHERN MN.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR NDZ006>008-
014>016-024-026>030-038-039-049-052>054.
WINTER STORM WATCH FROM 6 AM CST TUESDAY THROUGH WEDNESDAY
AFTERNOON FOR NDZ006>008-014>016-024-026>030-038-039-049-
052>054.
MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR MNZ001>009-
013>015-022-027-029-030-040.
WINTER STORM WATCH FROM 6 AM CST TUESDAY THROUGH WEDNESDAY
AFTERNOON FOR MNZ001>009-013>017-022>024-027>032-040.
WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR MNZ016-017-023-
024-028-031-032.
&&
$$
UPDATE...SPEICHER
SHORT TERM...JR
LONG TERM...JR/GODON
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS TULSA OK
352 PM CST TUE DEC 3 2013
.DISCUSSION...
WOW FOLKS...WHAT A FORECAST TODAY. THERE WILL BE SEVERAL ROUNDS OF
WINTRY PRECIPITATION THAT WILL HAVE IMPACTS ON TRAVEL AND POSSIBLY
THE POWER GRID AS WELL. I WILL DIVE INTO EACH FACET OF THE
FORECAST BELOW...ONE BY ONE.
FIRST...OF SOMEWHAT LESS IMPORTANCE...WILL BE FOG POTENTIAL
TONIGHT. FOR THE PAST 2 DAYS WE`VE HAD WIDESPREAD DENSE FOG.
TONIGHT...WHAT I SEE THAT IS DIFFERENT WILL BE THE DEPTH OF THE
NEAR GROUND MOIST LAYER. MODEL MOISTURE PROFILES DRY OUT FROM TOP
TO BOTTOM WITH TIME TONIGHT...ALTHOUGH THERE MAY BE ENOUGH REMNANT
MOISTURE NEAR THE GROUND FOR SOME PATCHY FOG DEVELOPMENT...SOME
POSSIBLY DENSE. FWIW...THE HRRR BREAKS OUT DENSE FOG OVER A GOOD
PORTION OF EASTERN OK THIS EVENING...AND IT HAS BEEN HANDLING THE
FOG WELL THE PAST 2 NIGHTS.
NOW TO THE MEAT OF THIS FORECAST. A VERY AMPLIFIED UPPER PATTERN
IS EVOLVING OVER THE WESTERN CONUS AS I TYPE...WITH A RIDGE NOSING
WELL UP INTO ALASKA...AND A DEEP POSITIVE TILT DOWNSTREAM TROUGH
DEVELOPING OVER THE WESTERN CONUS. THIS HAS CREATED A CROSS-POLAR
FLOW CLEAR FROM SIBERIA DOWN INTO NORTH AMERICA. WORSE YET...THIS
PATTERN WILL LIKELY PERSIST FOR ABOUT A WEEK...SENDING SHOT AFTER
SHOT OF ARCTIC AIR DOWN INTO THE CONUS AS DISTURBANCES ROTATE
AROUND THE POLAR VORTEX OVER CENTRAL CANADA. THE INITIAL SURGE OF
ARCTIC AIR WILL ARRIVE TOMORROW...AND WILL UNDERCUT A STRONG BELT
OF SW FLOW ALOFT DOWNSTREAM FROM THE WESTERN TROUGH. THE FIRST
ROUND OF PRECIP WILL BE FORCED MAINLY BY LOW TO MID LVL
FRONTOGENESIS...WHICH WILL KICK IN BY EARLY THURSDAY. THE MODELS
ARE IN VERY GOOD AGREEMENT ON A RATHER IMPRESSIVE BAND OF PRECIP
FROM SE OK UP INTO NRN AR ON THURSDAY. NE OK WILL BE ON THE FRINGE
OF THE BEST FN FORCING...AND WILL SEE LIGHTER PRECIP AMOUNTS AS A
RESULT. IN FACT...PORTIONS OF OSAGE COUNTY MAY NOT SEE ANYTHING
WITH THIS FIRST ROUND. NAM/GFS TEMP PROFILES SUGGEST THAT A BAND
OF SIGNIFICANT ICING IS POSSIBLE FROM SE OK UP INTO W CNTRL AR AND
PORTIONS OF NW AR. SOME PLACES HERE MAY PICK UP A QUARTER INCH OR
MORE OF ICE ACCUMULATION...WHICH COULD CAUSE POWER OUTAGES AND
SIGNIFICANT TRAVEL ISSUES. A BAND OF SIGNIFICANT SLEET
ACCUMULATION IS POSSIBLE JUST NORTH OF WHERE THE ZR/IP LINE SETS
UP...MOST LIKELY FROM E CNTRL AND EVENTUALLY PORTIONS OF SE OK
INTO W CNTRL AND NW AR AS THE COLDER AIR GETS DEEPER WITH TIME
FROM NORTH TO SOUTH. THIS COULD CAUSE SIGNIFICANT TRAVEL ISSUES AS
WELL. SOME LIGHT SNOW ACCUMULATION IS MOST LIKELY NEAR THE KANSAS
BORDER. THE FN FORCING SHIFTS SOUTHEAST BY THURSDAY EVENING AND
WEAKENS OVER OUR AREA...ENDING THE FIRST ROUND OF PRECIP.
ROUND TWO BEGINS LATE THURSDAY NIGHT INTO FRIDAY...AS A SHORTWAVE
TROUGH EJECTS EAST FROM THE WESTERN TROUGH OVER THE PLAINS. THE
INCREASING QG FORCING WILL BE MORE BROAD AND WILL COVER MORE OF
THE FORECAST AREA THIS GO AROUND. MODELS SUGGEST THAT A NICE WSW-
ENE ORIENTED DEFORMATION ZONE WILL SET UP FROM SOUTH CENTRAL INTO
NORTHEAST OK AND NORTHWEST AR. LAYER TEMP PROFILES FORECAST BY THE
GFS/ECMWF SUGGEST SNOW OR SNOW/SLEET FOR NE OK AND NW AR...WITH
MORE SLEET ACROSS MUCH OF SE OK AND W CNTRL AR. BASED ON QPF...THIS
COULD LEAD TO SEVERAL INCHES OF SNOW/SLEET ACCUMULATION.
HOWEVER...THE WARM NOSE MAY BE STRONG ENOUGH FOR MORE ZR AND THUS
ICE ACCUMULATION ACROSS FAR SE OK INTO W CNTRL AR LATE THURSDAY
NIGHT AS ROUND TWO GETS GOING. BY FRIDAY MORNING...THE WARM LAYER
IS ERODED ENOUGH FROM THE NORTH TO SHIFT THE BEST ICE POTENTIAL
SOUTH AND EAST OF THE FORECAST AREA. BOTH THE GFS/ECMWF SUGGEST
THAT THE QG FORCING WILL SHUT OFF RAPIDLY BY MIDDAY FRIDAY AS THE
WAVE SHEARS OUT AND LIFTS NORTHEAST OVER THE PLAINS. ROUND TWO
WILL LIKELY BRING MORE TRAVEL HEADACHES ACROSS A LARGER PORTION OF
THE FORECAST AREA. POWER INTERRUPTIONS EITHER MAY DEVELOP OR
CONTINUE OVER AREAS THAT HAVE RECEIVED THE MOST ICE ACCUMULATION
FROM THESE FIRST TWO ROUNDS OF PRECIP.
ROUND THREE GETS GOING OVER THE WEEKEND...AS ANOTHER SHORTWAVE
EMBEDDED WITHIN THE WESTERN CONUS LONGWAVE TROUGH EJECTS NORTHEAST
OVER THE PLAINS...AND A BIT FARTHER NORTH THAN THE PREVIOUS WAVE.
IN ADDITION...WITH THE SURFACE FRONT AND BEST MOISTURE NOW SHUNTED
WELL TO OUR SOUTH AND EAST...THERE WILL NOT BE AS MUCH MOISTURE
FOR THIS SYSTEM TO WORK WITH. INCREASING LOW/MID LVL ISENTROPIC
LIFT WILL RESULT IN AT LEAST LIGHT AMOUNTS OF PRECIPITATION
BEGINNING LATE SATURDAY AND INTO SUNDAY. MODEL SOUNDINGS ARE
FAIRLY DRY OVERALL IN THE CRUCIAL -10 TO -15C LAYER...WITH
MOISTURE MAINLY CONFINED BELOW 700MB. THIS WOULD SUGGEST THAT
PATCHY FREEZING DRIZZLE IS A POSSIBILITY AND HAS THUS BEEN ADDED
TO THE GRIDS. THERE ARE SOME HINTS OF PERIODIC MOISTENING DEEP
ENOUGH FOR ICE PRODUCTION...SO I HAVE ELECTED TO USE MULTIPLE
PRECIP TYPES IN THE GRIDS. THE GFS/ECMWF SUGGEST THAT THE WARM LAYER
WILL EXPAND NORTH INTO OUR AREA SOME DURING THIS TIME...AND THUS
ANOTHER ROUND OF MIXED PRECIP IS POSSIBLE...HOWEVER I WILL
REITERATE THAT PRECIP SHOULD REMAIN LIGHT OVERALL. THIS ROUND OF
PRECIP SHOULD END BY SUNDAY EVENING AS THE WARM CONVEYOR AND
RESULTING ISENTROPIC LIFT SHIFTS EAST OF OUR AREA.
FINALLY...BY EARLY NEXT WEEK THE GFS/ECMWF ARE IN GOOD AGREEMENT
THAT THE PERSISTENT WESTERN LONGWAVE TROUGH WILL LIFT OUT AND SHIFT
EAST OVER THE PLAINS. SOME LIFT AND LIMITED MOISTURE COULD SQUEEZE
OUT SOME LIGHT SNOW ON MONDAY. THIS SHOULD END WINTER PRECIP
CHANCES FOR THE TIME BEING...WHEW.
BOTTOM LINE...AN EXTENDED PERIOD OF VERY COLD WEATHER ALONG WITH
SEVERAL ROUNDS OF WINTRY PRECIPITATION ARE EXPECTED. TRAVEL WILL
BE AFFECTED...AND POWER DELIVERY MAY BE AS WELL IN SOME AREAS.
LOWS ON SATURDAY AND TUESDAY MORNING ARE EXPECTED TO DIP DOWN INTO
THE SINGLE DIGITS WITH WIND CHILLS BELOW ZERO OVER PORTIONS OF THE
AREA. GET READY FOLKS.
THE WINTER STORM WATCH WILL BE CONTINUED FOR THE ENTIRE FORECAST
AREA...WITH WARNINGS LIKELY TO FOLLOW EITHER TONIGHT OR WEDNESDAY.
LACY
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 44 49 28 28 / 0 0 20 70
FSM 48 66 37 37 / 0 0 20 90
MLC 46 59 33 33 / 0 0 20 90
BVO 40 45 26 27 / 0 0 10 60
FYV 47 60 31 31 / 0 0 20 90
BYV 49 62 30 30 / 0 0 20 90
MKO 45 56 31 31 / 0 0 20 90
MIO 45 50 26 27 / 0 0 10 90
F10 44 53 29 30 / 0 0 20 80
HHW 47 70 39 39 / 0 0 20 90
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...WINTER STORM WATCH FROM 6 AM THURSDAY TO 6 PM FRIDAY FOR OKZ054-
OKZ055-OKZ056-OKZ057-OKZ058-OKZ059-OKZ060-OKZ061-OKZ062-
OKZ063-OKZ064-OKZ065-OKZ066-OKZ067-OKZ068-OKZ069-OKZ070-
OKZ071-OKZ072-OKZ073-OKZ074-OKZ075.
WINTER STORM WATCH FROM NOON THURSDAY TO 6 PM FRIDAY FOR OKZ049-
OKZ053-OKZ076.
AR...WINTER STORM WATCH FROM 6 AM THURSDAY TO 6 PM FRIDAY FOR ARZ001-
ARZ002-ARZ010-ARZ011-ARZ019.
WINTER STORM WATCH FROM NOON THURSDAY TO 6 PM FRIDAY FOR ARZ020-
ARZ029.
&&
$$
LONG TERM....30
AREA FORECAST DISCUSSION
NWS NORMAN OK
1146 PM CST MON DEC 2 2013
.AVIATION...03 DEC 06Z TAF ISSUANCE...
VISIBILITIES DUE TO FOG CONTINUE TO BE THE PRIMARY FORECAST
CONCERN. SITES ACROSS SOUTH CENTRAL AND SERN OK CONTINUE TO DROP
TO 1/4SM. SITES ACROSS CENTRAL OK HAVE BEEN MORE STEADY OVER THE
PAST FEW HOURS...4 TO 5SM. FROM VISUAL AND SAT OBSERVATIONS...
EXPECT VIS TO CONTINUE TO DROP ACROSS CENTRAL OK THROUGH THE
OVERNIGHT HOURS... IMPACTING KOKC AND KOUN...WITH 1/4SM EXPECTED
THROUGH DAY BREAK. ACROSS NRN OK... DO NOT EXPECT THE IMPACTS TO
BE AS GREAT... WITH 3 TO 5SM FOG FOR KPNC THROUGH THE EARLY
MORNING HOURS. HAVE MENTIONS OF LIGHT FOG AS WELL...5SM... FOR
KCSM/KHBR/KLAW/KSPS AS WELL THROUGH THE EARLY MORNING. WINDS WILL
GRADUALLY INCREASE THROUGH TOMORROW AND REMAIN OUT OF THE S/SW
THROUGH THE EVENING.
JTK
&&
.PREV DISCUSSION... /ISSUED 928 PM CST MON DEC 2 2013/
UPDATE...
ADDED GRANT AND GARFIELD COUNTIES TO THE DENSE FOG ADVISORY.
ALSO...NUDGED LOWS DOWN TONIGHT ACROSS PARTS OF NORTHERN
OKLAHOMA. INCREASED CLOUD COVER ACROSS THE AREA TONIGHT.
DISCUSSION...
ADDED THE LOCATIONS MENTIONED ABOVE TO THE DENSE FOG ADVISORY BASED
ON LATEST HRRR MODEL OUTPUT. THE REST OF THE DENSE FOG ADVISORY
IS IN GOOD SHAPE. ADA HAS BEEN REPORTING 1/4SM FG OVER THE PAST
THREE HOURS AND FEEL HIGHLY CONFIDENT THAT THIS DENSE FOG WILL
SPREAD NORTH AND WEST OVER THE NEXT FEW HOURS. THE OKLAHOMA CITY
METRO AREA SHOULD SEE DENSE FOG DEVELOPMENT IN THE FEW HOURS. FOG
MAY NOT BE AS DENSE AS LAST NIGHT ESPECIALLY WITH INCREASING
SURFACE WINDS TO MIX THE AIR AND MORE HIGH LEVEL CLOUDS TO LIMIT
RADIATIONAL COOLING. REGARDLESS...SOME LOCATIONS WILL EXPERIENCE
SIGNIFICANTLY REDUCED VISIBILITIES WHICH WILL AFFECT DRIVERS.
TEMPERATURES WERE LOWERED TONIGHT ACROSS NORTHERN OKLAHOMA WHERE
THEY HAVE ALREADY FALLEN TO PREVIOUSLY FORECAST LOWS. HIGH LEVEL
CLOUD COVER WILL CONTINUE...BUT MAY DIMINISH LATE TONIGHT.
KEPT THE CURRENT FIRE WEATHER WATCH FOR PARTS OF WESTERN AND
SOUTHWESTERN OKLAHOMA AS WELL AS WESTERN NORTH TEXAS TUESDAY
AFTERNOON...THOUGH WINDS APPEAR TO BE MARGINAL BASED ON LATEST
MODEL OUTPUT.
MBS
PREV DISCUSSION... /ISSUED 521 PM CST MON DEC 2 2013/
UPDATE...
ISSUED A DENSE FOG ADVISORY FROM 7 PM TONIGHT TO 10 AM TUESDAY
ROUGHLY ALONG AND EAST OF I-35.
DISCUSSION...
DENSE FOG WILL AGAIN DEVELOP TONIGHT IN THE OKLAHOMA CITY...
DURANT...ARDMORE...PAULS VALLEY...STILLWATER...AND PONCA
CITY AREAS. LATEST HRRR RUNS HAVE BEEN CONSISTENT WITH DEVELOPING
DENSE FOG DEVELOPING AROUND 7 PM THIS EVENING AROUND COALGATE AND
ATOKA THEN EXPANDING IT NORTH AND WEST...WHICH SEEMS REASONABLE.
THE DENSE FOG SHOULD ARRIVE IN THE OKLAHOMA CITY METRO AREA
BETWEEN 10 PM AND 1 AM.
VISIBILITIES WILL BE 1/4 MILE OR LESS IN MANY LOCATIONS IN
THE ADVISORY AREA LATE TONIGHT INTO TUESDAY MORNING...BUT MAY
NOT BE QUITE AS LOW COMPARED TO LAST NIGHT/THIS MORNING DUE TO
A SLIGHT INCREASE IN SURFACE WINDS. ANY FOG SHOULD DISSIPATE
QUICKER TUESDAY MORNING COMPARED TO THIS MORNING DUE TO THE
STRONGER WINDS.
PRODUCTS HAVE BEEN UPDATED.
MBS
PREV DISCUSSION... /ISSUED 334 PM CST MON DEC 2 2013/
DISCUSSION...
DENSE FOG IS EXPECTED TO DEVELOP AGAIN TONIGHT...MAINLY NEAR AND
EAST OF INTERSTATE-35. DENSE FOG ADVISORIES WILL BE ISSUED LATER
THIS EVENING AS NEEDED. WE DO EXPECT THE FOG TO BURN OFF QUICKER
TOMORROW WITH INCREASING S/SW FLOW.
WRF RUNS NOW EXTENDING INTO BEGINNING OF UPCOMING STORM AND
INITIALLY ARE FORECASTING IMPACTS CLOSER TO GFS...A WETTER AND
HIGHER IMPACT SCENARIO. THE ECM STILL STICKING TO ITS FORECAST OF
LESS ACCUMULATIONS. HISTORICALLY...FOR THE EXCESSIVE ICE EVENTS WE
TYPICALLY SEE DEEP ZONE OF STRONG WARM ADVECTION/LLJ ALONG
ELEVATED BAROCLINIC ZONE/TOP OF THE FRONT/AND THIS IS NOT READILY
APPARENT HERE. STRONG/VERY STRONG MID AND UPPER LEVEL JET DYNAMICS
FORCING RESPONSE WELL ABOVE FRONTAL SURFACE IN THE FORM OF
700-600MB WAA AND FRONTOGENESIS. COINCIDENCE OF THIS FORCING AND
AVAILABLE MOISTURE/DRY-AIR ENTRAINMENT STILL LEAD US TO QUESTION
THE WIDESPREAD HIGH QPFS FROM A FEW OF THE MODELS. NONETHELESS...
GIVEN TRANSIENT TIME OF UPPER JET AND AGREEMENT OF PRECIPITATION
BAND LOCATION FROM ALL MODELS...THERE WILL LIKELY BE A NARROW BAND
OF ENHANCED PRECIP NEAR OR JUST SOUTH OF THE I-44 CORRIDOR. THE
CLOSER TO I-44 THE GREATER CHANCE FOR HEAVY SNOW. FARTHER
SOUTH...FREEZING RAIN AND ICE ACCUMULATION.
STILL LOOKS LIKE EVENT WILL BE ASSOCIATED WITH INITIAL SHIELD OF
RAIN/FREEZING RAIN WESTERN NORTH TEXAS AND SOUTHERN HALF OF
OKLAHOMA LATE WEDNESDAY NIGHT THROUGH THURSDAY. SECOND IMPULSE
INDUCES POSSIBLY HEAVIER PRECIP OVER LARGER AREA LATE THURSDAY
NIGHT THROUGH MIDDAY FRIDAY. APPEARS THAT LEAST AMOUNT OF IMPACTS
WILL BE OVER FAR NORTHERN OKLAHOMA. MODEL TRENDS WILL BE WATCHED
CLOSELY AND IF TRENDS CONTINUE WINTER STORM WATCH WILL LIKELY BE
ISSUED IN THE NEXT COUPLE OF FORECAST PACKAGES.
LIGHT SNOW AND/OR FLURRIES ALONG WITH VERY COLD CONDITIONS WILL
CONTINUE THROUGH THE WEEKEND BUT LITTLE IN THE WAY OF
ACCUMULATIONS EXPECTED SATURDAY AND SUNDAY.
03
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 41 68 35 43 / 0 0 0 0
HOBART OK 38 69 33 45 / 0 0 0 0
WICHITA FALLS TX 40 76 38 52 / 0 0 0 0
GAGE OK 33 68 26 35 / 0 0 0 0
PONCA CITY OK 36 65 31 40 / 0 0 0 0
DURANT OK 45 70 46 54 / 0 0 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...DENSE FOG ADVISORY UNTIL 10 AM CST TUESDAY FOR OKZ007-008-012-
013-018>020-024>032-039>043-045>048-050>052.
FIRE WEATHER WATCH TUESDAY AFTERNOON FOR OKZ014-016-021-022-
033>038-044.
TX...FIRE WEATHER WATCH TUESDAY AFTERNOON FOR TXZ083>089.
&&
$$
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
1108 AM EST TUE DEC 3 2013
.DISCUSSION...CLOUD COVER SLOWLY ERODING ACROSS NE HALF OF THE
REGION AS FLOW MORE SOUTHWESTERLY BUT HANGING IN ALONG THE PLATEAU
AND SE TN AND SW NC WHERE FLOW IS MORE SOUTHEASTERLY AND UPSLOPE.
EXPECT THE CLEARING SKIES TO CONTINUE NE SO HAVE RAISED HIGHS A
COUPLE DEGREES AND ADDED SOME PARTLY CLOUDY WORDING. LATEST RUC MODEL
SHOWS SHORTWAVE ENERGY TO MOVE ACROSS SE TN AND SW NC SO KEEPING
LOW POPS THERE FOR AFTERNOON. LATE AFTERNOON AND EARLY EVENING
STRONGER SHORTWAVE TO MOVE ACROSS ENTIRE FORECAST AREA SO CLOUDS
LIKELY TO INCREASE IN THE NORTHEAST AFTER 21Z. UPDATED FORECAST SENT.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
TD
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
1005 PM CST Wed Dec 4 2013
.DISCUSSION...
See Aviation Discussion below.
&&
.AVIATION...
Cold front now showing up on KMAF 88D just entering Midland
County...even faster than the RUC and new NAM. This will put fropa
at KMAF right around issuance time, and thru the other terminals
by 14Z. NAM buffer soundings keep cigs VFR thru the forecast
period except for KHOB and KCNM, which may see a few hours of
post-frontal MVFR cigs. Lack of lower-lvl moisture was evident in
the KMAF 00Z raob. We`ve tempo`d in -RA for fropa all terminals
except KMAF and KHOB, where soundings suggest -FZRA.
&&
PREV DISCUSSION... /ISSUED 227 PM CST Wed Dec 4 2013/
DISCUSSION...
Today looks like our last warm day for a while before Arctic air
moves in tomorrow and stays around for much of the next week.
Strong winds over the Guadalupe Mountains continue this afternoon
with some locations still gusting over 55 mph. Will keep the High
Wind Warning going through this evening when the strong winds should
begin to diminish. Winds have also picked up across northern Eddy
and Lea counties so have opted to include them in a short fused Wind
Advisory ending this evening.
This afternoons warm temperatures will soon be a distant memory as
we await a strong cold front set to arrive tonight. The Arctic front
is currently sitting across the Big Country and southern TX
Panhandle as diurnal effects have stalled it. The front will get
a strong push later tonight and should move through most of the
Permian Basin by sunrise Thursday. Temperatures will fall quickly
into the 30s behind the front with even some locations staying in
the 20s tomorrow afternoon across the far northern Permian Basin
and western Low Rolling Plains. At the same time, precipitation
will begin to break out across with area within moderate
isentropic lift. Temperatures will be cold enough for freezing
rain and possibly some sleet over northern parts of the Permian
Basin. With confidence increasing in the frozen precipitation,
will issue a winter weather advisory for the northern Permian
Basin and western Low Rolling Plains until Friday morning. These
areas could see ice accumulations up to 1/4" by Thursday
afternoon; then mix with sleet and snow Thursday night and Friday
morning. More counties will likely be added to the advisory
overnight as freezing temperatures will be delayed until Thursday
afternoon and night further south and west. Models indicate more
precipitation will develop over the area Thursday night as the
cold air deepens. This may cause major travel problems by Friday
morning especially across the Permian Basin where the heaviest
sleet and freezing rain is expected. We could also see an inch or
so of snow from Lamesa over to Snyder. Precip should end by mid
morning Friday leaving behind very chilly temperatures and cloudy
skies. Temperatures then nosedive into the teens and 20s by
Saturday morning with areas north of the Pecos River likely not
making it above freezing during the day. There could also be some
freezing drizzle across the Permian Basin Saturday and Saturday
night as the low levels of the atmosphere saturates.
We try to warm a bit Sunday, but am very skeptical of the guidance
as the Arctic air makes it all the way to the Gulf coast. Will stay
below guidance for now and keep high temperatures mostly in the 40s
and 50s.
Yet another shot of Arctic air will arrive Monday with well below
normal temperatures expected into next week.
hluchan
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...WINTER WEATHER ADVISORY from 5 AM Thursday to 5 AM MST Friday
FOR THE FOLLOWING ZONES... Northern Lea County.
TX...WINTER WEATHER ADVISORY from 6 AM Thursday to 6 AM CST Friday
FOR THE FOLLOWING ZONES... Borden...Dawson...Gaines...
Howard...Martin...Mitchell...Scurry.
&&
$$
44
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
928 PM CST WED DEC 4 2013
.UPDATE...
THE EVENING BALLOON DATA HAS BEEN ANALYZED AND AT 850MB IT
INDICATES VERY COLD AIR ACROSS THE PLAINS IS NOW POURING SOUTH.
DODGE CITY REPORTED -10C AT 850MB AND NORTH PLATTE HAD -17C WITH
NORTH WINDS AT 25 TO 30 KNOTS. SURFACE WINDS AND PRESSURES WERE
NOW RISING TO OUR NORTHWEST...IN RESPONSE TO THE VERY STRONG COLD
ADVECTION OCCURRING ABOVE THE SURFACE. TEMPERATURES AT 850MB
ACROSS THE PLAINS GIVE A BETTER INDICATION OF WHAT OUR SURFACE
TEMPERATURES WILL BE THAN THE CURRENT SURFACE TEMPERATURES THERE
DO. THIS IS BECAUSE THE AIR BEHIND A COLD FRONT UNDERGOES GRADUAL
SUBSIDENCE BEFORE IT REACHES THE SURFACE AT A GIVEN LOCATION.
850MB IS A GREAT LEVEL TO ANALYZE ACROSS KANSAS AND NEBRASKA FOR
AN APPROXIMATION OF WHAT OUR SURFACE TEMPS WILL BE HERE. ASSUMING
ONLY ADIABATIC COMPRESSIONAL WARMING TAKES PLACE .../I.E. NO
SUNSHINE/RADIATIVE/LATENT HEAT CHANGES OCCUR/... THE -10C
EXTRAPOLATES TO SURFACE TEMPS IN THE MID 30S F AND THE -17C TO MID
20S F. THIS AIR WILL ARRIVE INTO OUR AREA THURSDAY AND THURSDAY
NIGHT. ALSO OF NOTE...THE 6-12 HOUR OLD FORECASTS FROM THE
GFS/SREF/NAM WERE 2-4 DEG C TOO WARM AT 850MB ACROSS THE PLAINS.
ALL OF THIS RAISES OUR CONFIDENCE THAT MOST OF THE MODELS CONTINUE
TO UNDERESTIMATE THE SPEED OF THIS COLD AIR AND THAT THE COLDER
TEMPS ARE LIKELY TO ARRIVE EARLIER.
THE RAP HAS SO FAR DONE AN EXCELLENT JOB WITH THIS FRONT AND IT IS
FORECASTING THE FRONT TO CLEAR THE SOUTHERN CWA BY SUNRISE. AS A
RESULT HAVE LOWERED TEMPERATURES SIGNIFICANTLY ACROSS THE SOUTHERN
ZONES FOR LOWS TONIGHT AND HIGHS TOMORROW. THE RAP IS ALSO
FORECASTING THE FREEZING LINE TO REACH THE I-20 CORRIDOR BY MIDDAY
TOMORROW. MEANWHILE A BAND OF PRECIPITATION WILL DEVELOP AND
STREAM ACROSS THE NORTHWESTERN AND NORTHERN ZONES. MOST OF THIS
PRECIP WILL ORIGINATE ABOVE 700MB OR ABOUT 10000 FEET WHICH WILL
LIMIT ITS INTENSITY. FURTHERMORE THE AIR BELOW IT WILL BE VERY DRY
AND SOME OF THIS PRECIP WILL BE LOST TO EVAPORATION BEFORE IT CAN
REACH THE SURFACE. NONETHELESS IT IS LIKELY THAT PRECIP WILL REACH
THE GROUND ACROSS THE NORTHWEST AND NORTHERN ZONES AND EVAPORATIVE
COOLING WILL PUSH SURFACE TEMPS INTO THE 20S. WHILE GROUND
SURFACES ARE STILL VERY WARM...TEMPS IN THE 20S AND WINDS OF 15
MPH WILL BE ENOUGH TO COOL ELEVATED SURFACES/BRIDGES BELOW
FREEZING TO START ACCUMULATING ICE BY THE AFTERNOON HOURS. THE
WINTER STORM WARNING BEGINS AT NOON IN THE AREA ALONG AND NORTH OF
A CISCO TO WEATHERFORD TO SHERMAN LINE AND THIS REGION MAY BEGIN
TO SEE IMPACTS BY AFTERNOON.
FARTHER SOUTH ACROSS THE I-20 CORRIDOR...FREEZING TEMPERATURES ARE
POSSIBLE BY AFTERNOON...BUT PRECIPITATION COVERAGE AND INTENSITY
BECOMES A LITTLE MORE QUESTIONABLE. EITHER WAY FEEL THAT IT IS TOO
LOW OF A RISK FOR IMPACTS TO BRING THE WARNING INTO THE AFTERNOON
HOURS...EVEN THOUGH LIGHT FREEZING RAIN MAY BEGIN TO SHOW UP ON
CARS AND TREES BY THE AFTERNOON RUSH.
THE ONLY CHANGES TO THE PREVIOUS FORECAST FOR THURSDAY NIGHT AND
FRIDAY WERE TO INCREASE ICE ACCUMULATION AMOUNTS NORTH OF I-20.
CONFIDENCE CONTINUES TO INCREASE THAT SIGNIFICANT ICE ACCUMULATION
FROM FREEZING RAIN WILL OCCUR AS TEMPERATURES SHOULD DROP INTO THE
MID TO UPPER 20S AS A LARGE AREA OF MODERATE PRECIPITATION MOVES
INTO THE REGION. EVEN DESPITE THE VERY WARM TEMPERATURES ALOFT AND
RAIN DROPS THAT WILL LIKELY BE A FEW DEGREES ABOVE FREEZING WHEN
THEY REACH THE GROUND...STRONG COLD/DRY ADVECTION WILL BE ONGOING
DURING THIS EVENT WHICH SHOULD KEEP TEMPERATURES BELOW FREEZING
AND LIKELY IN 20S ACROSS THE WARNING AREA. WE ARE PARTICULARLY
CONCERNED ABOUT DENTON...COLLIN...COOKE...GRAYSON...AND FANNIN
COUNTIES WHERE THE JUXTAPOSITION OF HIGH AMOUNTS OF FREEZING RAIN
AND TEMPERATURES IN THE MID TO UPPER 20S WILL OCCUR. SIGNIFICANT
ICING OF TREES IN THIS AREA WOULD LEAD TO LIMB BREAKAGE AND POWER
OUTAGES THAT MAY LAST FOR DAYS IN SOME COMMUNITIES. FURTHERMORE
NOT ALL TREES HAVE LOST THEIR LEAVES YET WHICH WILL ADD TO TREE
LIMB STRESS DUE TO THE WEIGHT OF MORE ICE. MORE SLEET IS POSSIBLE
FOR THE NORTHWESTERN ZONES WHICH SHOULD LIMIT ICE ACCUMULATION ON
TREES AND HOPEFULLY MITIGATE DAMAGE TO THE POWER GRID BUT IT IS A
TOUGH CALL. ACROSS THE REMAINDER OF THE WARNING AREA...AND
ESPECIALLY ALONG AND NORTH OF I-20...SIGNIFICANT TRAVEL
DISRUPTIONS WILL OCCUR FROM ICE ON ROADS. ICE MAY LINGER FOR DAYS
AS SKIES STAY CLOUDY AND TEMPERATURES REMAIN BELOW FREEZING.
ANOTHER SHOT AT SLEET AND FREEZING RAIN WILL OCCUR ON SATURDAY
AFTERNOON AND NIGHT.
WILL BE UPDATING THE WINTER STORM WARNING TO INCREASE THE
SEVERITY OF THE WORDING AND IMPACTS ACROSS THE NORTHERN AND
NORTHWESTERN ZONES.
TR.92
&&
.AVIATION...
/00Z TAFS/
CONCERNS...FROPA TIMING...CEILINGS...ONSET OF FREEZING PRECIP.
THE INITIAL FRONTAL BOUNDARY HAS BEEN SLOW TO PROGRESS SOUTHWARD...
AND AT NIGHTFALL...IT REMAINS DRAPED ACROSS THE DALLAS/FORT WORTH
METROPLEX. THE ARCTIC AIR IS STILL IN OKLAHOMA...BUT PRESSURE RISES
THERE SUGGEST THE AIR MASS WILL DEEPEN AND BEGIN SURGING SOUTHWARD
THIS EVENING. METROPLEX TAFS BEGIN WITH NORTH WINDS...SPEEDS
INCREASING AFTER MIDNIGHT WHEN THE ARCTIC AIR ARRIVES.
PERFECT PROG GUIDANCE SUGGEST SOME MVFR CEILINGS WILL BE POSSIBLE
OVERNIGHT NEAR THE TOP OF THE POST-FRONTAL LAYER. MOS IS LESS
IMPRESSED...AND WITH THE STRATUS UPSTREAM CONFINED TO NORTHEAST
OKLAHOMA...WILL FORGO INCLUDING ANY AT THIS TIME. WILL BEGIN MVFR
CEILINGS WITH LIGHT RAIN MID-MORNING...BUT SIGNIFICANT PRECIP
WILL LIKELY WAIT UNTIL THURSDAY EVENING. HAVE INTRODUCED THE ONSET
OF FREEZING RAIN MID-EVENING THURSDAY WITHIN THE EXTENDED PORTION
OF THE DFW TAF. SINCE THE FREEZING LINE MAY REACH THE METROPLEX
EARLIER THAN THE CURRENT FORECAST...AVIATION INTERESTS SHOULD
CONTINUE TO MONITOR UPDATES ABOUT THIS DEVELOPING WINTER WEATHER
SITUATION.
WACO...
SOUTH FLOW MAY PREVAIL AT WACO UNTIL AFTER MIDNIGHT. ONSET OF
LIGHT PRECIPITATION IN CENTRAL TEXAS WILL LIKELY BE LATER THAN AT
METROPLEX SITES...POTENTIALLY MID-AFTERNOON THURSDAY. AT THIS
TIME...TEMPERATURES ARE EXPECTED TO STAY ABOVE FREEZING AT WACO
UNTIL AROUND DAYBREAK FRIDAY MORNING...WHEN THE RAIN MAY
TRANSITION TO FREEZING RAIN...BUT THIS TOO IS SUBJECT TO CHANGE.
25
&&
.PREV DISCUSSION... /ISSUED 321 PM CST WED DEC 4 2013/
WE/VE UPGRADED AND EXPANDED THE WINTER STORM WATCH TO A WINTER
STORM WARNING NORTHWEST OF A GOLDTHWAITE TO CANTON LINE AND ADDED
A WINTER WEATHER ADVISORY SOUTHEASTWARD TO A TEMPLE TO PALESTINE
LINE.
TODAY/S FRONT HAS REACHED A NORTH OF PARIS TO EASTLAND LINE BY 2
PM AND WILL CONTINUE TO MOVE SOUTH OVERNIGHT. MUCH COLDER AIR IS
SPREADING THROUGH OKLAHOMA AND WILL INVADE NORTH TEXAS LATER TONIGHT
AND CENTRAL TEXAS THURSDAY MORNING AND EARLY AFTERNOON. LIGHT RAIN
SHOULD BEGIN OVERNIGHT DUE TO FRONTAL LIFTING AND ISENTROPIC
UPGLIDE.
THURSDAY THROUGH FRIDAY...TEMPERATURES WILL NOT CHANGE VERY MUCH ON
THURSDAY DUE TO COLD AIR ADVECTION...CLOUDS AND PRECIPITATION.
SOME FREEZING RAIN WILL BE POSSIBLE OVER THE FAR NORTHWEST
COUNTIES BEFORE SUNSET. CONDITIONS WILL CONTINUE TO DETERIORATE AS
FREEZING RAIN BECOMES MORE PREDOMINATE AS THE COLD AIR DEEPENS.
MODERATE TO HEAVY RAINFALL AND FREEZING RAIN IS POSSIBLE THURSDAY
MID EVENING THROUGH EARLY FRIDAY MORNING GENERALLY NORTHWEST OF A
HAMILTON TO DALLAS TO PARIS LINE WITH THE AXIS ALIGNED FROM
COMANCHE TO SHERMAN. ISOLATED THUNDER MAY ALSO OCCUR AFTER
MIDNIGHT. IF THIS RAINFALL MATERIALIZES...THEN A SIGNIFICANT ICE
STORM COULD DEVELOP IF TEMPERATURES CAN FALL INTO THE 20S.
HOWEVER...THIS COULD ALSO BE A CASE WHERE RAIN FALLING THROUGH THE
WARM NOSE ALOFT GAINS ENOUGH HEAT TO PREVENT SURFACE TEMPERATURES
FROM FALLING MUCH BELOW FREEZING. THUS...THE TEMPORAL AND SPATIAL
CHARACTERISTICS OF THE TRANSITION TO ALL FREEZING RAIN REMAINS
HARD TO DETERMINE. IT COULD REMAIN WEST OF THE METROPLEX THROUGH
FRIDAY MIDDAY OR IT COULD MIGRATE EAST ACROSS THE METROPLEX BEFORE
DAYBREAK AND DURING THE MORNING HOURS. BY ANY TOKEN...TEMPERATURES
ABOVE HOUSE TOPS WILL BE COLD ENOUGH FOR ICE TO ACCUMULATE ON
ELEVATED SURFACES AND STRUCTURES...AND THIS COULD BRING DOWN POWER
LINES AND TREE LIMBS...AND MAKE BRIDGES AND OVERPASSES ICY.
AS THE FREEZING AIR CONTINUES TO DEEPEN ON FRIDAY...SLEET WILL
BECOME MORE LIKELY...ESPECIALLY OVER THE NORTHERN HALF OF THE CWA.
SLEET AMOUNTS COULD TOTAL UP TO ONE HALF INCH. THE WINTRY
PRECIPITATION SHOULD END FOR FRIDAY NIGHT...BUT IT WILL RETURN
SATURDAY THROUGH SUNDAY AS AN UPPER DISTURBANCE MOVES ACROSS THE
REGION.
WITH COLD TEMPERATURES REMAINING ACROSS THE REGION THROUGH MUCH OF
THIS FORECAST...ICE ACCUMULATIONS WILL LIKELY HANG AROUND THROUGH
THE WEEKEND AND IN SOME AREAS THROUGH TUESDAY.
ONCE THE ARCTIC AIR SETTLES OVER THE REGION...HIGHS ARE NOT
EXPECTED TO WARM ABOVE 40 DEGREES UNTIL THE MIDDLE OF NEXT WEEK.
LOWS WILL VARY DAY TO DAY...BUT WILL LIKELY WILL BE IN THE TEENS
AND 20S THIS WEEKEND THROUGH TUESDAY MORNING. SOME RED RIVER
LOCATIONS MAY SEE SINGLE DIGITS ON TUESDAY MORNING. 75
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 36 37 26 29 19 / 20 50 90 50 10
WACO, TX 40 43 29 32 21 / 20 30 80 50 10
PARIS, TX 35 36 27 29 17 / 20 50 90 60 10
DENTON, TX 35 35 24 26 17 / 20 60 90 50 10
MCKINNEY, TX 35 36 25 27 18 / 20 50 90 50 10
DALLAS, TX 37 37 26 29 20 / 20 50 90 50 10
TERRELL, TX 37 38 27 29 20 / 20 40 90 50 10
CORSICANA, TX 40 41 29 33 22 / 20 30 80 60 10
TEMPLE, TX 42 44 30 32 22 / 20 30 80 60 10
MINERAL WELLS, TX 35 35 23 25 17 / 20 60 70 40 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THURSDAY TO 6 PM CST FRIDAY FOR
TXZ094-095-104>107-118>123-130>134-141>145.
WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM CST FRIDAY FOR TXZ135-
146>148-156>161.
WINTER STORM WARNING FROM NOON THURSDAY TO 6 PM CST FRIDAY FOR
TXZ091>093-100>103-115>117-129.
&&
$$
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
903 PM CST Wed Dec 4 2013
.UPDATE...
The much anticipated Arctic cold front is, not surprisingly, running
ahead of schedule. As of 03Z, surface obs indicate the front is
located near a Lamesa to Colorado city line and pushing southeast
rapidly. This timing is about 3 hours faster than previously thought
forecasted, therefore updated the winds to account for this change.
Also, winds across the Guadalupe Mountains and southeast New Mexico
have dropped below warning/advisory criteria so an update was needed
to remove wording from zones. Otherwise, the rest of the forecast
tonight looks to be on track and no additional changes were made.
Zones will be sent shortly.
&&
.PREV DISCUSSION... /ISSUED 520 PM CST Wed Dec 4 2013/
DISCUSSION...
See Aviation Discussion below.
AVIATION...
Latest sfc analysis shows the cold front hung up NW-SE across the
Texas Panhandle/S. Plains, where it has been most of the
afternoon. Latest NAM continues to begin moving it SW after 00Z,
and buffer soundings fropa it thru KMAF at around 00Z, and most
other terminals around 13Z. It stalls out around KCNM during the
day Thursday. The latest RUC moves the front a little faster, and
we`ll update timing as necessary. Attm, cigs look to stay just
above MVFR everywhere but KHOB, which could see MVFR cigs around
18Z. -RA will accompany fropa all terminals except KMAF, where
buffer soundings suggest a chance of FZRA.
PREV DISCUSSION... /ISSUED 227 PM CST Wed Dec 4 2013/
DISCUSSION...
Today looks like our last warm day for a while before Arctic air
moves in tomorrow and stays around for much of the next week.
Strong winds over the Guadalupe Mountains continue this afternoon
with some locations still gusting over 55 mph. Will keep the High
Wind Warning going through this evening when the strong winds should
begin to diminish. Winds have also picked up across northern Eddy
and Lea counties so have opted to include them in a short fused Wind
Advisory ending this evening.
This afternoons warm temperatures will soon be a distant memory as
we await a strong cold front set to arrive tonight. The Arctic front
is currently sitting across the Big Country and southern TX
Panhandle as diurnal effects have stalled it. The front will get
a strong push later tonight and should move through most of the
Permian Basin by sunrise Thursday. Temperatures will fall quickly
into the 30s behind the front with even some locations staying in
the 20s tomorrow afternoon across the far northern Permian Basin
and western Low Rolling Plains. At the same time, precipitation
will begin to break out across with area within moderate
isentropic lift. Temperatures will be cold enough for freezing
rain and possibly some sleet over northern parts of the Permian
Basin. With confidence increasing in the frozen precipitation,
will issue a winter weather advisory for the northern Permian
Basin and western Low Rolling Plains until Friday morning. These
areas could see ice accumulations up to 1/4" by Thursday
afternoon; then mix with sleet and snow Thursday night and Friday
morning. More counties will likely be added to the advisory
overnight as freezing temperatures will be delayed until Thursday
afternoon and night further south and west. Models indicate more
precipitation will develop over the area Thursday night as the
cold air deepens. This may cause major travel problems by Friday
morning especially across the Permian Basin where the heaviest
sleet and freezing rain is expected. We could also see an inch or
so of snow from Lamesa over to Snyder. Precip should end by mid
morning Friday leaving behind very chilly temperatures and cloudy
skies. Temperatures then nosedive into the teens and 20s by
Saturday morning with areas north of the Pecos River likely not
making it above freezing during the day. There could also be some
freezing drizzle across the Permian Basin Saturday and Saturday
night as the low levels of the atmosphere saturates.
We try to warm a bit Sunday, but am very skeptical of the guidance
as the Arctic air makes it all the way to the Gulf coast. Will stay
below guidance for now and keep high temperatures mostly in the 40s
and 50s.
Yet another shot of Arctic air will arrive Monday with well below
normal temperatures expected into next week.
hluchan
&&
.PRELIMINARY POINT TEMPS/POPS...
ANDREWS TX 34 36 21 31 / 10 60 60 10
BIG SPRING TX 33 35 22 30 / 20 60 70 10
CARLSBAD NM 51 52 29 39 / 10 40 50 0
DRYDEN TX 55 62 36 42 / 10 30 40 10
FORT STOCKTON TX 46 48 29 38 / 10 50 50 10
GUADALUPE PASS TX 46 49 30 36 / 10 50 40 0
HOBBS NM 40 40 21 32 / 10 50 50 0
MARFA TX 46 61 33 47 / 10 50 40 10
MIDLAND INTL AIRPORT TX 33 34 23 32 / 20 60 60 10
ODESSA TX 36 37 23 33 / 10 60 60 10
WINK TX 45 47 26 38 / 10 50 50 10
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...WINTER WEATHER ADVISORY from 5 AM Thursday to 5 AM MST Friday
FOR THE FOLLOWING ZONES... Northern Lea County.
TX...WINTER WEATHER ADVISORY from 6 AM Thursday to 6 AM CST Friday
FOR THE FOLLOWING ZONES... Borden...Dawson...Gaines...
Howard...Martin...Mitchell...Scurry.
&&
$$
44/27
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
520 PM CST Wed Dec 4 2013
.DISCUSSION...
See Aviation Discussion below.
&&
.AVIATION...
Latest sfc analysis shows the cold front hung up NW-SE across the
Texas Panhandle/S. Plains, where it has been most of the
afternoon. Latest NAM continues to begin moving it SW after 00Z,
and buffer soundings fropa it thru KMAF at around 00Z, and most
other terminals around 13Z. It stalls out around KCNM during the
day Thursday. The latest RUC moves the front a little faster, and
we`ll update timing as necessary. Attm, cigs look to stay just
above MVFR everywhere but KHOB, which could see MVFR cigs around
18Z. -RA will accompany fropa all terminals except KMAF, where
buffer soundings suggest a chance of FZRA.
&&
.PREV DISCUSSION... /ISSUED 227 PM CST Wed Dec 4 2013/
DISCUSSION...
Today looks like our last warm day for a while before Arctic air
moves in tomorrow and stays around for much of the next week.
Strong winds over the Guadalupe Mountains continue this afternoon
with some locations still gusting over 55 mph. Will keep the High
Wind Warning going through this evening when the strong winds should
begin to diminish. Winds have also picked up across northern Eddy
and Lea counties so have opted to include them in a short fused Wind
Advisory ending this evening.
This afternoons warm temperatures will soon be a distant memory as
we await a strong cold front set to arrive tonight. The Arctic front
is currently sitting across the Big Country and southern TX
Panhandle as diurnal effects have stalled it. The front will get
a strong push later tonight and should move through most of the
Permian Basin by sunrise Thursday. Temperatures will fall quickly
into the 30s behind the front with even some locations staying in
the 20s tomorrow afternoon across the far northern Permian Basin
and western Low Rolling Plains. At the same time, precipitation
will begin to break out across with area within moderate
isentropic lift. Temperatures will be cold enough for freezing
rain and possibly some sleet over northern parts of the Permian
Basin. With confidence increasing in the frozen precipitation,
will issue a winter weather advisory for the northern Permian
Basin and western Low Rolling Plains until Friday morning. These
areas could see ice accumulations up to 1/4" by Thursday
afternoon; then mix with sleet and snow Thursday night and Friday
morning. More counties will likely be added to the advisory
overnight as freezing temperatures will be delayed until Thursday
afternoon and night further south and west. Models indicate more
precipitation will develop over the area Thursday night as the
cold air deepens. This may cause major travel problems by Friday
morning especially across the Permian Basin where the heaviest
sleet and freezing rain is expected. We could also see an inch or
so of snow from Lamesa over to Snyder. Precip should end by mid
morning Friday leaving behind very chilly temperatures and cloudy
skies. Temperatures then nosedive into the teens and 20s by
Saturday morning with areas north of the Pecos River likely not
making it above freezing during the day. There could also be some
freezing drizzle across the Permian Basin Saturday and Saturday
night as the low levels of the atmosphere saturates.
We try to warm a bit Sunday, but am very skeptical of the guidance
as the Arctic air makes it all the way to the Gulf coast. Will stay
below guidance for now and keep high temperatures mostly in the 40s
and 50s.
Yet another shot of Arctic air will arrive Monday with well below
normal temperatures expected into next week.
hluchan
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...HIGH WIND WARNING until 8 PM MST this evening FOR THE FOLLOWING
ZONES... Guadalupe Mountains of Eddy County.
WINTER WEATHER ADVISORY from 5 AM Thursday to 5 AM MST Friday
FOR THE FOLLOWING ZONES... Northern Lea County.
WIND ADVISORY until 8 PM MST this evening FOR THE FOLLOWING
ZONES... Eddy County Plains...Northern Lea County.
TX...HIGH WIND WARNING until 8 PM MST this evening FOR THE FOLLOWING
ZONES... Guadalupe Mountains.
WINTER WEATHER ADVISORY from 6 AM Thursday to 6 AM CST Friday
FOR THE FOLLOWING ZONES... Borden...Dawson...Gaines...
Howard...Martin...Mitchell...Scurry.
&&
$$
44
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1005 AM CST TUE DEC 3 2013
.UPDATE...
WE/VE EXTENDED THE DENSE FOG UNTIL NOON FOR AREAS ALONG AND NORTH
OF A DENTON TO SULPHUR SPRINGS LINE. MANY REPORTING SITES CONTINUE
TO HAVE VISIBILITIES OF 1/4 MILE OR LESS AND THIS SHOULD PERSIST
INTO MIDDAY LIKE IT DID YESTERDAY. SOME LOCATIONS MAY CONTINUE TO
HAVE FOG PROBLEMS INTO EARLY AFTERNOON...AND WE/LL DECIDE AROUND
MIDDAY WHETHER TO EXTEND IT AGAIN. 75
&&
.AVIATION...
A BAND OF CIRRUS MOVED OVER THE METROPLEX SLOWING THE COOLING A
BIT...BUT IT HAS MOVED EAST OF TAF SITES AND FOG IS STARTING TO
FORM AT DFW AS I WRITE THIS. DENSE FOG REMAINS AS CLOSE AS
DENTON...LANCASTER...AND MESQUITE WHICH APPEARS SIMILAR TO
CONDITIONS YESTERDAY MORNING. HRRR CONTINUES TO SHOW FOG REACHING
DFW AND DAL...BUT NOT THE WESTERN/SOUTHERN SITES. 4KM WRF STOPS
FOG JUST EAST OF TAF SITES AND RUC SOUNDINGS SHOW GROUND FOG.
WITH TWO HOURS TO SUNRISE...CONDITIONS ARE RIPE FOR COOLING TO
CONTINUE AND FOG TO FORM...SO WILL KEEP THE IFR FORECASTS FOR DFW
& DAL. LIKE YESTERDAY...FOG LAYER WILL BE FAIRLY THIN AND SHOULD
BURN OFF QUICKLY AFTER SUNRISE. WITH A STRONG SOUTHWESTERLY LOW
LEVEL JET TOMORROW MORNING...NO RESTRICTIONS TO CIG/VSBY ARE
EXPECTED. 84
&&
.PREV DISCUSSION...
/ISSUED 426 AM CST TUE DEC 3 2013/
STILL SOME MILD WEATHER TO ENJOY BEFORE THE ARCTIC BLAST ARRIVES.
DENSE FOG DEVELOPED OVERNIGHT NORTHEAST OF A BOWIE TO DALLAS TO
CANTON LINE. THIS FOG WILL CONTINUE TO CAUSE SOME PROBLEMS
THROUGH MID MORNING. THUS THE DENSE FOG ADVISORY WILL REMAIN IN
EFFECT UNTIL 10 AM. SOME PATCHY FOG WILL OCCUR FARTHER SOUTH FROM
CORSICANA TO HEARNE EASTWARD...AND IF IT BECOMES WIDESPREAD
ENOUGH WILL EXPAND THE DENSE FOG ADVISORY. AFTER THE FOG BURNS
OFF IT WILL BE A NICE LATE FALL DAY ACROSS THE REGION WITH HIGHS
IN THE UPPER 60S NORTHEAST TO AROUND 80 WEST.
ALTHOUGH TIMING DIFFERENCES BETWEEN THE MODELS CONTINUE CONCERNING
THE NEXT COLD FRONT...THEY HAVE COME CLOSER TO AGREEMENT THAN THEY
WERE 24 HOURS AGO. THE GFS REMAINS THE FASTEST WITH THE FRONT BUT
IS SLOWER THAN IT WAS 24 HOURS AGO...BRINGING THE FRONT INTO THE
NORTHWESTERN ZONES LATE WEDNESDAY MORNING. THE GFS THEN SLOWS
THE SOUTHWARD PROGRESS CONSIDERABLY...BRINGING THE FRONT DOWN
TO A PARIS TO EASTLAND LINE BY 00Z THURSDAY...AND TO A CANTON TO
LAMPASAS BY 12Z THURSDAY. THE ECMWF BRINGS THE FRONT ACROSS THE
RED RIVER AROUND 00Z THURSDAY AND THROUGH THE SOUTHEAST BY 12Z
THURSDAY. THE CMC ALSO BRINGS THE FRONT INTO THE NORTHWEST BY 00Z
THURSDAY BUT BY 12Z...IT PLACES THE FRONT NEAR A TYLER TO TEMPLE
LINE. THE NAM BRINGS THE FRONT DOWN TO A PARIS TO DFW TO HAMILTON
LINE BY 00Z THURSDAY AND THEN THROUGH THE SOUTHEAST BY 12Z
THURSDAY.
THE MODELS AGREE THAT THE FRONT WILL NOT REACH THE I-20 CORRIDOR
UNTIL LATE WEDNESDAY AFTERNOON AT THE EARLIEST AND WILL NOT MOVE
THROUGH THE SOUTHEASTERN COUNTIES UNTIL AROUND OR SHORTLY AFTER
DAYBREAK THURSDAY. THUS HAVE WARMED WEDNESDAY/S TEMPERATURES 5 TO
OVER 10 DEGREES AREA WIDE. LIKEWISE HAVE RAISED THURSDAY MORNINGS
LOWS ACROSS ALL BUT THE NORTHWEST BY 5 TO 10 DEGREES.
THE ARCTIC FRONT WILL MOVE THROUGH NORTH TEXAS THURSDAY WITH MUCH
COLDER TEMPERATURES. THE HIGHS WILL LIKELY OCCUR EARLY MORNING
WITH TEMPERATURES STEADY OR SLOWLY FALLING DURING THE DAY. AN
APPROACHING SHORTWAVE AND UPGLIDE OVER THE FRONT WILL RESULT IN
RAIN STARTING THURSDAY AND INCREASING THURSDAY NIGHT. AS
TEMPERATURES FALL BELOW FREEZING ACROSS THE NORTHWEST...THE RAIN
WILL CHANGE TO FREEZING RAIN THURSDAY NIGHT. BY DAYBREAK FRIDAY
THE FREEZING LINE MAY BE DOWN TO NEAR A SULPHUR SPRINGS TO
KILLEEN LINE. HAVE JUST LEFT A MENTION OF RAIN AT WACO AND
KILLEEN FOR NOW...BUT IT WILL BE CLOSE. THE PRECIPITATION SHOULD
COME TO A TEMPORARY END FROM SOUTHWEST TO NORTHEAST FRIDAY
AFTERNOON AS A SHORTWAVE MOVES OFF TO THE EAST.
UNFORTUNATELY...WITH THE TROUGH STILL BACK TO OUR WEST...WE WILL
REMAIN UNDER THE GUN FOR ADDITIONAL SHORTWAVES TO MOVE ACROSS
OVER THE REGION THE WEEKEND BRINGING A CHANCE OF A WINTRY MIX OF
PRECIPITATION. FORTUNATELY PRECIPITATION AMOUNTS SHOULD NOT BE
HEAVY. THE MAIN TROUGH WILL FINALLY MOVE ACROSS THE SOUTHERN
PLAINS SUNDAY NIGHT...BRINGING AN END TO THE PRECIPITATION
CHANCES BUT COOLER THAN NORMAL TEMPERATURES WILL CONTINUE INTO
THE EARLY PART OF NEXT WEEK. 58
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 74 55 77 38 42 / 0 5 10 20 60
WACO, TX 77 57 79 47 52 / 0 5 10 20 50
PARIS, TX 69 52 72 40 44 / 0 5 5 20 70
DENTON, TX 72 50 73 36 39 / 0 5 5 20 60
MCKINNEY, TX 71 51 75 38 41 / 0 5 10 20 60
DALLAS, TX 74 56 77 39 43 / 0 5 10 20 60
TERRELL, TX 71 57 76 41 47 / 0 5 10 20 60
CORSICANA, TX 74 61 77 48 52 / 0 5 10 20 60
TEMPLE, TX 78 57 79 53 56 / 0 5 10 20 50
MINERAL WELLS, TX 77 52 77 36 40 / 0 5 10 20 60
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR TXZ092>095-103>107.
&&
$$
/75
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
511 AM CST TUE DEC 3 2013
.AVIATION...
A BAND OF CIRRUS MOVED OVER THE METROPLEX SLOWING THE COOLING A
BIT...BUT IT HAS MOVED EAST OF TAF SITES AND FOG IS STARTING TO
FORM AT DFW AS I WRITE THIS. DENSE FOG REMAINS AS CLOSE AS
DENTON...LANCASTER...AND MESQUITE WHICH APPEARS SIMILAR TO
CONDITIONS YESTERDAY MORNING. HRRR CONTINUES TO SHOW FOG REACHING
DFW AND DAL...BUT NOT THE WESTERN/SOUTHERN SITES. 4KM WRF STOPS
FOG JUST EAST OF TAF SITES AND RUC SOUNDINGS SHOW GROUND FOG.
WITH TWO HOURS TO SUNRISE...CONDITIONS ARE RIPE FOR COOLING TO
CONTINUE AND FOG TO FORM...SO WILL KEEP THE IFR FORECASTS FOR DFW
& DAL. LIKE YESTERDAY...FOG LAYER WILL BE FAIRLY THIN AND SHOULD
BURN OFF QUICKLY AFTER SUNRISE. WITH A STRONG SOUTHWESTERLY LOW
LEVEL JET TOMORROW MORNING...NO RESTRICTIONS TO CIG/VSBY ARE
EXPECTED. 84
&&
.PREV DISCUSSION...
/ISSUED 426 AM CST TUE DEC 3 2013/
STILL SOME MILD WEATHER TO ENJOY BEFORE THE ARCTIC BLAST ARRIVES.
DENSE FOG DEVELOPED OVERNIGHT NORTHEAST OF A BOWIE TO DALLAS TO
CANTON LINE. THIS FOG WILL CONTINUE TO CAUSE SOME PROBLEMS
THROUGH MID MORNING. THUS THE DENSE FOG ADVISORY WILL REMAIN IN
EFFECT UNTIL 10 AM. SOME PATCHY FOG WILL OCCUR FARTHER SOUTH FROM
CORSICANA TO HEARNE EASTWARD...AND IF IT BECOMES WIDESPREAD
ENOUGH WILL EXPAND THE DENSE FOG ADVISORY. AFTER THE FOG BURNS
OFF IT WILL BE A NICE LATE FALL DAY ACROSS THE REGION WITH HIGHS
IN THE UPPER 60S NORTHEAST TO AROUND 80 WEST.
ALTHOUGH TIMING DIFFERENCES BETWEEN THE MODELS CONTINUE CONCERNING
THE NEXT COLD FRONT...THEY HAVE COME CLOSER TO AGREEMENT THAN THEY
WERE 24 HOURS AGO. THE GFS REMAINS THE FASTEST WITH THE FRONT BUT
IS SLOWER THAN IT WAS 24 HOURS AGO...BRINGING THE FRONT INTO THE
NORTHWESTERN ZONES LATE WEDNESDAY MORNING. THE GFS THEN SLOWS
THE SOUTHWARD PROGRESS CONSIDERABLY...BRINGING THE FRONT DOWN
TO A PARIS TO EASTLAND LINE BY 00Z THURSDAY...AND TO A CANTON TO
LAMPASAS BY 12Z THURSDAY. THE ECMWF BRINGS THE FRONT ACROSS THE
RED RIVER AROUND 00Z THURSDAY AND THROUGH THE SOUTHEAST BY 12Z
THURSDAY. THE CMC ALSO BRINGS THE FRONT INTO THE NORTHWEST BY 00Z
THURSDAY BUT BY 12Z...IT PLACES THE FRONT NEAR A TYLER TO TEMPLE
LINE. THE NAM BRINGS THE FRONT DOWN TO A PARIS TO DFW TO HAMILTON
LINE BY 00Z THURSDAY AND THEN THROUGH THE SOUTHEAST BY 12Z
THURSDAY.
THE MODELS AGREE THAT THE FRONT WILL NOT REACH THE I-20 CORRIDOR
UNTIL LATE WEDNESDAY AFTERNOON AT THE EARLIEST AND WILL NOT MOVE
THROUGH THE SOUTHEASTERN COUNTIES UNTIL AROUND OR SHORTLY AFTER
DAYBREAK THURSDAY. THUS HAVE WARMED WEDNESDAY/S TEMPERATURES 5 TO
OVER 10 DEGREES AREA WIDE. LIKEWISE HAVE RAISED THURSDAY MORNINGS
LOWS ACROSS ALL BUT THE NORTHWEST BY 5 TO 10 DEGREES.
THE ARCTIC FRONT WILL MOVE THROUGH NORTH TEXAS THURSDAY WITH MUCH
COLDER TEMPERATURES. THE HIGHS WILL LIKELY OCCUR EARLY MORNING
WITH TEMPERATURES STEADY OR SLOWLY FALLING DURING THE DAY. AN
APPROACHING SHORTWAVE AND UPGLIDE OVER THE FRONT WILL RESULT IN
RAIN STARTING THURSDAY AND INCREASING THURSDAY NIGHT. AS
TEMPERATURES FALL BELOW FREEZING ACROSS THE NORTHWEST...THE RAIN
WILL CHANGE TO FREEZING RAIN THURSDAY NIGHT. BY DAYBREAK FRIDAY
THE FREEZING LINE MAY BE DOWN TO NEAR A SULPHUR SPRINGS TO
KILLEEN LINE. HAVE JUST LEFT A MENTION OF RAIN AT WACO AND
KILLEEN FOR NOW...BUT IT WILL BE CLOSE. THE PRECIPITATION SHOULD
COME TO A TEMPORARY END FROM SOUTHWEST TO NORTHEAST FRIDAY
AFTERNOON AS A SHORTWAVE MOVES OFF TO THE EAST.
UNFORTUNATELY...WITH THE TROUGH STILL BACK TO OUR WEST...WE WILL
REMAIN UNDER THE GUN FOR ADDITIONAL SHORTWAVES TO MOVE ACROSS
OVER THE REGION THE WEEKEND BRINGING A CHANCE OF A WINTRY MIX OF
PRECIPITATION. FORTUNATELY PRECIPITATION AMOUNTS SHOULD NOT BE
HEAVY. THE MAIN TROUGH WILL FINALLY MOVE ACROSS THE SOUTHERN
PLAINS SUNDAY NIGHT...BRINGING AN END TO THE PRECIPITATION
CHANCES BUT COOLER THAN NORMAL TEMPERATURES WILL CONTINUE INTO
THE EARLY PART OF NEXT WEEK.
58
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 74 55 77 43 45 / 0 5 10 20 60
WACO, TX 77 57 79 54 57 / 0 5 10 20 50
PARIS, TX 69 52 72 46 46 / 0 5 5 20 70
DENTON, TX 72 50 73 38 39 / 0 5 5 20 60
MCKINNEY, TX 71 51 75 41 41 / 0 5 10 20 60
DALLAS, TX 74 56 77 44 48 / 0 5 10 20 60
TERRELL, TX 71 57 76 48 48 / 0 5 10 20 60
CORSICANA, TX 74 61 77 53 54 / 0 5 10 20 60
TEMPLE, TX 78 57 79 56 58 / 0 5 10 20 50
MINERAL WELLS, TX 77 52 77 39 40 / 0 5 10 20 60
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR TXZ092>095-
103>107-120>123-135.
&&
$$
/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
510 AM CST TUE DEC 3 2013
.AVIATION...
A BAND OF CIRRUS MOVED OVER THE METROPLEX SLOWING THE COOLING A
BIT...BUT IT HAS MOVED EAST OF TAF SITES AND FOG IS STARTING TO
FORM AS I WRITE THIS. DENSE FOG REMAINS AS CLOSE AS
DENTON...LANCASTER...AND MESQUITE WHICH APPEARS SIMILAR TO
YESTERDAY. HRRR CONTINUES TO SHOW FOG REACHING DFW AND DAL...BUT
NOT THE WESTERN/SOUTHERN SITES. 4KM WRF STOPS FOG JUST EAST OF
TAF SITES AND RUC SOUNDINGS SHOW GROUND FOG. WITH TWO HOURS TO
SUNRISE...CONDITIONS ARE RIPE FOR COOLING TO CONTINUE AND FOG TO
FORM...SO WILL KEEP THE IFR FORECASTS FOR DFW & DAL. LIKE
YESTERDAY...FOG LAYER WILL BE FAIRLY THIN AND SHOULD BURN OFF
QUICKLY AFTER SUNRISE. WITH A STRONG SOUTHWESTERLY LOW LEVEL JET
TOMORROW MORNING...NO RESTRICTIONS TO CIG/VSBY ARE EXPECTED. 84
&&
.PREV DISCUSSION... /ISSUED 426 AM CST TUE DEC 3 2013/
STILL SOME MILD WEATHER TO ENJOY BEFORE THE ARCTIC BLAST ARRIVES.
DENSE FOG DEVELOPED OVERNIGHT NORTHEAST OF A BOWIE TO DALLAS TO
CANTON LINE. THIS FOG WILL CONTINUE TO CAUSE SOME PROBLEMS
THROUGH MID MORNING. THUS THE DENSE FOG ADVISORY WILL REMAIN IN
EFFECT UNTIL 10 AM. SOME PATCHY FOG WILL OCCUR FARTHER SOUTH FROM
CORSICANA TO HEARNE EASTWARD...AND IF IT BECOMES WIDESPREAD
ENOUGH WILL EXPAND THE DENSE FOG ADVISORY. AFTER THE FOG BURNS
OFF IT WILL BE A NICE LATE FALL DAY ACROSS THE REGION WITH HIGHS
IN THE UPPER 60S NORTHEAST TO AROUND 80 WEST.
ALTHOUGH TIMING DIFFERENCES BETWEEN THE MODELS CONTINUE CONCERNING
THE NEXT COLD FRONT...THEY HAVE COME CLOSER TO AGREEMENT THAN THEY
WERE 24 HOURS AGO. THE GFS REMAINS THE FASTEST WITH THE FRONT BUT
IS SLOWER THAN IT WAS 24 HOURS AGO...BRINGING THE FRONT INTO THE
NORTHWESTERN ZONES LATE WEDNESDAY MORNING. THE GFS THEN SLOWS
THE SOUTHWARD PROGRESS CONSIDERABLY...BRINGING THE FRONT DOWN
TO A PARIS TO EASTLAND LINE BY 00Z THURSDAY...AND TO A CANTON TO
LAMPASAS BY 12Z THURSDAY. THE ECMWF BRINGS THE FRONT ACROSS THE
RED RIVER AROUND 00Z THURSDAY AND THROUGH THE SOUTHEAST BY 12Z
THURSDAY. THE CMC ALSO BRINGS THE FRONT INTO THE NORTHWEST BY 00Z
THURSDAY BUT BY 12Z...IT PLACES THE FRONT NEAR A TYLER TO TEMPLE
LINE. THE NAM BRINGS THE FRONT DOWN TO A PARIS TO DFW TO HAMILTON
LINE BY 00Z THURSDAY AND THEN THROUGH THE SOUTHEAST BY 12Z
THURSDAY.
THE MODELS AGREE THAT THE FRONT WILL NOT REACH THE I-20 CORRIDOR
UNTIL LATE WEDNESDAY AFTERNOON AT THE EARLIEST AND WILL NOT MOVE
THROUGH THE SOUTHEASTERN COUNTIES UNTIL AROUND OR SHORTLY AFTER
DAYBREAK THURSDAY. THUS HAVE WARMED WEDNESDAY/S TEMPERATURES 5 TO
OVER 10 DEGREES AREA WIDE. LIKEWISE HAVE RAISED THURSDAY MORNINGS
LOWS ACROSS ALL BUT THE NORTHWEST BY 5 TO 10 DEGREES.
THE ARCTIC FRONT WILL MOVE THROUGH NORTH TEXAS THURSDAY WITH MUCH
COLDER TEMPERATURES. THE HIGHS WILL LIKELY OCCUR EARLY MORNING
WITH TEMPERATURES STEADY OR SLOWLY FALLING DURING THE DAY. AN
APPROACHING SHORTWAVE AND UPGLIDE OVER THE FRONT WILL RESULT IN
RAIN STARTING THURSDAY AND INCREASING THURSDAY NIGHT. AS
TEMPERATURES FALL BELOW FREEZING ACROSS THE NORTHWEST...THE RAIN
WILL CHANGE TO FREEZING RAIN THURSDAY NIGHT. BY DAYBREAK FRIDAY
THE FREEZING LINE MAY BE DOWN TO NEAR A SULPHUR SPRINGS TO
KILLEEN LINE. HAVE JUST LEFT A MENTION OF RAIN AT WACO AND
KILLEEN FOR NOW...BUT IT WILL BE CLOSE. THE PRECIPITATION SHOULD
COME TO A TEMPORARY END FROM SOUTHWEST TO NORTHEAST FRIDAY
AFTERNOON AS A SHORTWAVE MOVES OFF TO THE EAST.
UNFORTUNATELY...WITH THE TROUGH STILL BACK TO OUR WEST...WE WILL
REMAIN UNDER THE GUN FOR ADDITIONAL SHORTWAVES TO MOVE ACROSS
OVER THE REGION THE WEEKEND BRINGING A CHANCE OF A WINTRY MIX OF
PRECIPITATION. FORTUNATELY PRECIPITATION AMOUNTS SHOULD NOT BE
HEAVY. THE MAIN TROUGH WILL FINALLY MOVE ACROSS THE SOUTHERN
PLAINS SUNDAY NIGHT...BRINGING AN END TO THE PRECIPITATION
CHANCES BUT COOLER THAN NORMAL TEMPERATURES WILL CONTINUE INTO
THE EARLY PART OF NEXT WEEK.
58
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 74 55 77 43 45 / 0 5 10 20 60
WACO, TX 77 57 79 54 57 / 0 5 10 20 50
PARIS, TX 69 52 72 46 46 / 0 5 5 20 70
DENTON, TX 72 50 73 38 39 / 0 5 5 20 60
MCKINNEY, TX 71 51 75 41 41 / 0 5 10 20 60
DALLAS, TX 74 56 77 44 48 / 0 5 10 20 60
TERRELL, TX 71 57 76 48 48 / 0 5 10 20 60
CORSICANA, TX 74 61 77 53 54 / 0 5 10 20 60
TEMPLE, TX 78 57 79 56 58 / 0 5 10 20 50
MINERAL WELLS, TX 77 52 77 39 40 / 0 5 10 20 60
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR TXZ092>095-
103>107-120>123-135.
&&
$$
84/58
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
925 PM CST WED DEC 4 2013
.UPDATE...
HAD EARLIER BEEFED UP WIND GUSTS BEHIND THE COLD FRONT AND LATEST
NAM AND HRRR INDICATE WINDS WILL STAY UP OVERNIGHT AS TIGHT
GRADIENT AROUND DEEPENING LOW TRACKING NORTHEAST ACROSS NRN WI
MOVES ACROSS SRN WI. TEMPERATURES WILL ALSO FALL OFF FAST AS 925MB
TEMPS FALL 15C BETWEEN 00Z AND 12Z WEDNESDAY. GIVEN CURRENT TEMPS
NOT THAT FAR UPSTREAM...WILL LOWER LOWS A FEW DEGREES CLOSER TO
NAM12 2M TEMPS AND LOCAL MODEL VALUES...WHICH BRINGS TEENS INTO
THE WEST.
&&
.AVIATION/06Z TAFS/...
ADVECTION OF DRIER AIR JUST AHEAD OF THE FRONT...AND COLDER AIR
BEHIND IS RAISING CIGS ABOVE 1K FT AND UPSTREAM OBS INDICATE THIS
TREND SHOULD HOLD...THOUGH DOESN/T LOOK LIKE WE WILL LIFT UP TO
MVFR BEFORE DAYBREAK EXCEPT AN OUTSIDE CHANCE AT KMSN. PER RECENT
RAPID UPDATE MODEL SOUNDINGS WIND GUSTS SHOULD STAY UP THROUGH THE
NIGHT WITH COLD ADVECTION.
&&
.MARINE...
WILL KEEP CURRENT SMALL CRAFT ADVISORY HEADLINE AS IS. SOUTHWEST
WINDS GUSTING AT/ABOVE CRITERIA WILL SHIFT WEST OVERNIGHT AND
REMAIN GUSTY THROUGH THURSDAY NIGHT AS THEY TURN NORTHWEST AND
LOWER TO JUST BELOW CRITERIA BY FRIDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 325 PM CST WED DEC 4 2013/
.TONIGHT - CONFIDENCE...MEDIUM
997MB SURFACE LOW VCNTY LSE WILL FURTHER INTENSIFY. PER IMPRESSIVE
RISE/FALL COUPLET LOW WILL HEAD RIGHT ACROSS WESTERN LAKE SUPERIOR.
AS THIS DEEPENING OCCURS A STRONG COLD FRONT WILL WHIP THROUGH SRN
WI BRINGING AN END TO THE MILD/FOGGY AND MOIST CONDITIONS AND
TRANSITION TO A MUCH COLDER AND BLUSTERY REGIME. WILL HAVE TO WATCH
FOR SOME ICING UP OF THE WET ROADWAYS AND SIDEWALKS AS TEMPS DROP
BELOW FREEZING. WILL MENTION IN THE HWO. WITH THE FROPA VSBYS WILL
DRAMATICALLY IMPROVE SO CURRENT END TIMES OF DENSE FOG ADVISORY LOOK
OK. 925 TEMPS STARTING OUT AT 6-10C ON THE PLUS SIDE THIS EVENING
WILL PLUMMET TO 6-10C ON THE NEGATIVE SIDE BY 12Z...WITH GUSTY POST-
FRONTAL WEST WINDS.
THURSDAY - CONFIDENCE...MEDIUM
GRADUAL 850 MILLIBAR COLD AIR ADVECTION. TEMPS WILL NOT MOVE UPWARDS
TOO MUCH...WITH CONSENSUS TO KEEP TEMPS IN THE 20S. WIND CHILLS
CONSIDERABLY LOWER. GFS MUCH QUICKER ON DECREASING LOW LEVEL RH THAN
THE NAM. THIS REFLECTED TO SOME EXTENT IN THE MOS SKY COVER
FORECAST. WITHOUT A DEEP UPPER TROUGH ACROSS THE AREA BELIEVE SOME
BREAKS IN LOW CLOUDS ARE LIKELY THOUGH STRONG SOUTHWEST UPPER FLOW
MAY MAINTAIN SOME MID AND HIGH LEVEL CLOUD COVER AT TIMES. MAIN
STORY WILL BE THE COLD.
THURSDAY NIGHT THROUGH SATURDAY...FORECAST CONFIDENCE...MEDIUM TO
HIGH.
A VERY COLD PERIOD IS STILL EXPECTED WITH UNSEASONABLY COLD AIR
SETTLING INTO THE WESTERN GREAT LAKES. 85H TEMPS FALL AROUND 15C
FROM TODAY INTO THURSDAY...FALLING TO AROUND -10C BY 00Z/06. THE
COLD AIR GETS REINFORCED BY A PERSISTENT NORTHWEST WIND FLOW IN THE
LOW TO MID LEVELS THURSDAY NIGHT AND FRIDAY. HIGH TEMPS BOTH FRI
AND SAT WILL BE WELL BELOW NORMAL...MOST LIKELY BELOW THE NORMAL LOW
TEMP FOR THE 6TH AND 7TH. THE LOW TO MID LEVEL FLOW REMAINS
NORTHWEST THROUGH 00Z/08 SO NO LAKE EFFECT SNOW IS EXPECTED.
SEVERAL VERY WEAK CHANNELED VORTICITY AREAS ASSOCIATED WITH MID-
LEVEL SHORT WAVES PASS ACROSS SOUTHERN WI FRIDAY INTO FRIDAY NIGHT.
ALTHOUGH MID-LEVEL MOISTURE WILL BE SPARSE...THERE MAY BE JUST
ENOUGH FORCING TO SHAKE OUT SOME FLURRIES WITH LINGERING LOW LEVEL
MOISTURE CAUGHT BELOW INVERSION.
SATURDAY NIGHT THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM.
SLIGHT MODERATION IN TEMPERATURE BEGINS ON SUNDAY AS STRONG WEST TO
NORTHWEST FLOW SUCCUMBS TO UPSTREAM AMPLIFYING LONG WAVE TROFFING
OVER WESTERN CONUS. LOW TO MID-LEVEL WARM AIR ADVECTION SHIFTS INTO
THE SOUTHERN WI REGION ON SUN TIGHTENING BAROCLINIC ZONE. 12Z GFS
AND LATEST ECMWF CARRIES 85H CIRCULATION NORTHEAST ALONG THIS
BAROCLINIC ZONE ACROSS SOUTHERN WI/NORTHERN IL AREA SUN NGT INTO MON
AS MID-LEVEL SHORT WAVE TROUGH MOVES FROM THE CENTRAL PLAINS INTO
THE CENTRAL GTLAKES.
GFS AND ECMWF IN REASONABLE AGREEMENT ON CARRYING AROUND ONE QUARTER
INCH OF QPF ACROSS MUCH OF SOUTHERN WI DURING THIS PERIOD. CRITICAL
THICKNESSES FAVOR ALL SNOW. DRIER SNOW-LIQUID RATIOS OF 15 TO 20 TO
ONE AND A PERIOD OF STRONGER OMEGA TAPPING INTO A DEEPER DENDRITIC
GROWTH ZONE SHOULD RESULT IN SNOWFALLS OF 3 TO 6 INCHES ACROSS MOST
OF THE REGION...POSSIBLY A LITTLE MORE DUE TO SOME LAKE ENHANCEMENT.
WILL BE WATCHING THIS SYSTEM EVOLVE OVER THE NEXT SEVERAL DAYS BUT
LOOKING MORE LIKELY THAT THE FIRST WIDESPREAD WINTER WEATHER EVENT
WL AFFECT SRN WI LATE IN THE WEEKEND...POSSIBLY HAVING AN IMPACT ON
MONDAY MORNING.
THE COLD AIR GETS REINFORCED EARLY NEXT WEEK. WITH POTENTIAL FOR
WIDESPREAD SNOWCOVER...TEMPS LIKELY TO FALL INTO THE SINGLE DIGITS
AND POTENTIALLY LOWER.
AVIATION/00Z TAFS/...WIDESPREAD LIFR/VLIFR CONTINUES WITH MOIST LOW
LEVEL FLOW AHEAD OF STRENGTHENING LOW PRESSURE IN WRN AND NRN WI.
COLD FRONT ARRIVES LATE AFTN/ERLY EVE. WIDESPREAD DENSE FOG WILL BE
REPLACED BY STRONG COLD ADVECTION AND GUSTY WEST WINDS. THIS WILL
ALLOW FOR IMPROVEMENT IN CIGS AND VSBYS THOUGH STILL EXPECT DECENT
COVERAGE OF MVFR CIGS DURING THE NIGHT. ANY RAIN OR LIGHT MIX THIS
EVENING WILL BE ON THE LIGHT SIDE. PROGS SHOW NO MEASURABLE AFTER
6Z. SOUNDINGS SHOW DECREASING MOISTURE IN THE LOW LEVELS THURSDAY
MORNING THOUGH VFR BKN CONDITIONS MAY LINGER WITH STRONG SW UPPER
FLOW.
MARINE...DENSE FOG ADVISORY THROUGH 9 PM WITH PASSING COLD FRONT
ABOUT THAT TIME TO SCOUR OUT THE FOG. GUSTY WEST WINDS ENSUE AND
SMALL CRAFT ADVISORY WILL KICK IN AT 9 PM. WINDY CONDITIONS THROUGH
AT LEAST THURSDAY NIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 AM CST FRIDAY FOR LMZ643>646.
&&
$$
UPDATE...REM
TONIGHT/THURSDAY AND AVIATION/MARINE...COLLAR
THURSDAY NIGHT THROUGH WEDNESDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
550 PM CST WED DEC 4 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY MORNING)
ISSUED AT 316 PM CST WED DEC 4 2013
MAIN FORECAST CONCERN IS ON DEPARTING WEATHER SYSTEM...FOLLOWED
BY THE ARCTIC AIR MASS SURGE.
AS OF 3 PM WEDNESDAY...SURFACE ANALYSIS SHOWED 998 MB LOW
PRESSURE CENTERED NEAR DECORAH IOWA...WITH A WARM FRONT SITUATED
FROM NEAR PRAIRIE DU CHIEN WISCONSIN EASTWARD INTO SOUTHERN
WISCONSIN. FINALLY...THE LEADING EDGE OF THE COLD AIR WAS ALONG
THE I-35 CORRIDOR IN MINNESOTA AND IOWA.
THE SURFACE LOW IS EXPECTED TO LIFT NORTHEAST TO NORTHERN WISCONSIN
LATER THIS EVENING...THEN OVER LAKE SUPERIOR BY MIDNIGHT. THE COLD
FRONT SHOULD MAKE A CLEAN SWEEP ACROSS THE ENTIRE FORECAST AREA BY
03Z. THE SURGE OF WARMER AIR AHEAD OF THE SURFACE LOW IS KEEPING
WINTER PRECIPITATION THREAT LOW AT THIS TIME BUT STILL PLENTY OF
1/4 SM VISIBILITIES OR LOWER. LOCATIONS WILL HAVE TO WAIT FOR THE
COLD FRONTAL PASSAGE FOR IMPROVED VISIBILITIES...AND AREAS EAST OF
THE MISSISSIPPI RIVER AND NORTH OF I-90 IN WISCONSIN WILL LIKELY
HANG ONTO THE REDUCED VISIBILITIES THE LONGEST.
AHEAD OF THE COLD FRONT...STRONG LOW LEVEL LIFT AND SATURATION
COMBINED WITH VERY LITTLE ICE SATURATION ALOFT WILL LIKELY LEAD TO
DRIZZLE. HIGH RES MODELS SUCH AS THE HRRR CAPTURE THIS FAIRLY WELL.
BEHIND THE COLD FRONT...TEMPERATURES QUICKLY FALL INTO THE UPPER 20S
TO NEAR 30 DEGREES. ALTHOUGH MOISTURE IS TRAPPED IN THE LOW-LEVEL
INVERSION...THE LIFT BEGINS TO DROP OFF BUT THERE IS LIKELY TO BE
A PERIOD OF FREEZING DRIZZLE. AS EVEN COLDER AIR WORKS IN
ALOFT...SATURATION IN THE ICE GROWTH LAYER RETURNS SO PRECIPITATION
COULD END AS SNOW FLURRIES OR SNOW SHOWERS...ESPECIALLY ACROSS
CENTRAL MINNESOTA...INTO NORTH CENTRAL WISCONSIN BEFORE TAPERING
OFF ALTOGETHER TOWARD MIDNIGHT. AS SUCH...THE WINTER WEATHER
ADVISORY FOR TAYLOR/CLARK COUNTIES WILL REMAIN IN PLACE BUT LIKELY
COULD BE ENDED TOWARD MIDNIGHT.
FOR THURSDAY MORNING...GOOD CONSENSUS THAT PLENTY OF MOISTURE
REMAINS TRAPPED IN THE LOW LEVELS...MAINLY CENTERED AROUND 900 MB.
LIFT IS VERY WEAK BUT THE SURGE OF ARCTIC AIR SHOULD PUT THE DGZ
CLOSER TO 900 MB. THIS SUPPORTS VERY LIGHT BUT OCCASIONAL TO PERIODS
OF SNOW FLURRIES ACROSS NORTH CENTRAL WISCONSIN...BECOMING MORE
SCATTERED CLOSER TO ROCHESTER AND LA CROSSE.
.LONG TERM...(THURSDAY THROUGH WEDNESDAY)
ISSUED AT 316 PM CST WED DEC 4 2013
HIGHLIGHTS IN THE LONG TERM ARE ARCTIC AIR MASS SURGES AND
ACCUMULATING SNOWFALL POTENTIAL SUNDAY NIGHT.
THE CURRENT STORM SYSTEM DEEPENS AND QUICKLY DEPARTS NORTHEAST OF
THE GREAT LAKES REGION THURSDAY WHILE THE WESTERN TWO-THIRDS OF THE
CONUS REMAINS UNDER THE INFLUENCE OF THE UPPER LEVEL LONGWAVE
TROUGH. AS WELL ADVERTISED PREVIOUSLY...THE ARCTIC AIR SURGE
BEGINS IN EARNEST THURSDAY AND FRIDAY AS NOTED BY 850 MB
TEMPERATURES FALLING FROM AN AVERAGE OF -8C 12Z THURSDAY...TO -17C
BY 18Z FRIDAY. 850 MB STANDARDIZED ANOMALIES FALL TO 2 TO 2.5
DEGREES BELOW NORMAL...WHICH IS NOT RECORD COLD TERRITORY BUT
CERTAINLY UNSEASONABLE FOR THIS TIME OF YEAR. THE FRESH SNOWPACK
ACROSS CENTRAL MINNESOTA INTO NORTH CENTRAL WISCONSIN IS LIKELY TO
KEEP TEMPERATURES ON THE LOWER SIDE OF GUIDANCE AS WELL. LATEST
SNOW DEPTH READINGS SHOW ANYWHERE FROM A FEW INCHES FROM SOUTH CENTRAL
MINNESOTA...TO ALMOST 10 INCHES IN TAYLOR COUNTY. FORECAST
TEMPERATURES WERE NUDGED DOWN SLIGHTLY BY A FEW DEGREES FROM
PREVIOUS FORECAST.
A NOTICEABLY COLDER DAY ON TAP THURSDAY...WITH HIGHS ONLY IN THE
TEENS TO LOWER 20S. STIFF NORTHWEST WINDS WILL MAKE FOR WIND CHILL
READINGS IN THE SINGLE DIGITS ABOVE ZERO AT TIMES FOR MUCH OF THE
DAY. EVEN COLDER TEMPERATURES ARE EXPECTED FRIDAY AND
SATURDAY...MAINLY SINGLE DIGITS TO TEENS. FOR REFERENCE...NORMAL
HIGHS FOR THIS TIME OF YEAR ARE IN THE UPPER 20S TO LOWER 30S AND
LOWS IN THE TEENS. AS FAR AS LOW TEMPERATURES GO...SEVERAL
MORNINGS OF SUB ZERO READINGS EXPECTED FOR PARTS OF SOUTHEAST
MINNESOTA INTO NORTH CENTRAL WISCONSIN WHILE THE REST OF THE AREA
SHOULD FALL INTO THE SINGLE DIGITS ABOVE ZERO.
A WIND CHILL ADVISORY IS LIKELY NEEDED FOR PARTS OF THE AREA FRIDAY
NIGHT INTO SATURDAY AS THE SURFACE HIGH PRESSURE DROPS SOUTH TO OUR
WEST. THIS KEEPS A 10 TO 15 MPH WIND DURING THE OVERNIGHT ACROSS THE
AREA...RESULTING IN WIND CHILL READINGS IN THE 15 TO 25 DEGREE BELOW
ZERO RANGE NORTH OF INTERSTATE 90.
FOR THE UPCOMING WEEKEND...SATURDAY LOOKS TO BE ANOTHER UNSEASONABLY
COLD BUT DRY DAY WITH HIGHS IN THE SINGLE DIGITS TO TEENS.
HOWEVER...ON SUNDAY WITH THE MAIN UPPER LEVEL TROUGH REMAINING IN
PLACE ACROSS THE WESTERN CONUS...ANOTHER PIECE OF UPPER LEVEL ENERGY
DIGS INTO THE SOUTHWEST U.S. WHICH IS EXPECTED TO ALLOW A SURFACE
LOW TO DEVELOP IN THE LEE SIDE OF THE ROCKIES. PREVIOUS MODEL
CYCLES...AND THE 04.12Z GUIDANCE CONTINUE TO SHOW VERY GOOD
AGREEMENT THIS FAR OUT WHICH BOOSTS CONFIDENCE DURING THIS PERIOD.
THE SURFACE LOW IS EXPECTED TO BE NEAR CENTRAL OKLAHOMA 18Z
SUNDAY...THEN MOVE TOWARD CENTRAL ILLINOIS BY 06Z MONDAY. ON THE
NORTHWEST SIDE...AN INVERTED SURFACE TROUGH COUPLED WITH THE UPPER
LEVEL ENERGY IS LIKELY TO PROVIDE PLENTY OF LIFT TO SUPPORT SNOW
ACROSS MUCH OF THE FORECAST AREA. PRECIPITATION CHANCES WERE BOOSTED
TO LIKELY ACROSS NORTHEAST IOWA INTO WESTERN AND SOUTHERN
WISCONSIN...AND INTO THE 40 TO 50 PERCENT RANGE ELSEWHERE. STILL TOO
EARLY TO SPECULATE ON SNOWFALL AMOUNTS...BUT IMPACTFUL WEATHER IS
LOOKING LIKELY SUNDAY AFTERNOON INTO MONDAY MORNING FOR PORTIONS
OF THE AREA.
IN THE WAKE OF THE LATE WEEKEND SYSTEM...ANOTHER SURGE OF ARCTIC AIR
WILL USHER IN EVEN COLDER AIR WITH 850 MB TEMPERATURES IN THE -20 TO
-25C RANGE. AIDED BY A POSSIBLE FRESH SNOWPACK...WIDESPREAD MORNING
TEMPERATURES IN THE SINGLE DIGITS BELOW ZERO ARE LIKELY WITH TEENS
BELOW ZERO POSSIBLE IN SPOTS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 550 PM CST WED DEC 4 2013
PASSAGE OF COLD FRONT WILL RESULT IN A QUICK INCREASE IN WINDS AS A
TIGHT PRESSURE GRADIENT SWEEPS IN. STRONG/GUSTY THROUGH TONIGHT AND
THE BETTER PART OF THU CAN BE EXPECTED. DON/T SEE A LLWS THREAT AT
THIS TIME.
CIGS WILL REMAIN A CONCERN AND BUFKIT SOUNDINGS AND LOW LEVEL
MOISTURE FIELDS KEEP SOME SATURATION UNDER AN INVERSION THROUGH THE
BETTER PART OF THU. SOUNDINGS DO SUGGEST SOME IMPROVEMENT ON
THU...WITH SOME INCREASE IN CIG HEIGHTS...BUT LIKELY STAYING MVFR.
THESE 1500-2500 KFT CIGS COULD HANG AROUND INTO EARLY FRIDAY
MORNING...ON THE PESSIMISTIC SIDE. LATEST FOG/STRATUS SATELLITE
IMAGERY PAINT A SLIGHTLY DIFFERENT PICTURE THOUGH...SHOWING SOME
CLEARING ASSOCIATED WITH SOME MID LEVEL DRYING WORKING ACROSS NEB.
NO LOW CLOUDS INDICATED IN THIS REGION. THAT SAID...GOING TO LEAN ON
THE PESSIMISTIC SIDE FOR NOW. MODELS CAN HAVE A TENDENCY TO CLEAR
LOW LEVEL MOISTURE OUT TOO QUICKLY...BUT WILL MONITOR TRENDS
CLOSELY...AND UPDATE AS NEEDED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST THURSDAY FOR WIZ017-029.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ZT
LONG TERM....ZT
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1139 PM CST MON DEC 2 2013
.UPDATE...
ISSUED AT 1138 PM CST MON DEC 2 2013
DRIZZLE CONTINUES TO BECOME MORE AND MORE WIDESPREAD WEST OF THE
SNOW BAND CURRENTLY LOCATED FROM MEDFORD TO MARSHFILED WISCONSIN.
USING THE 03.04Z RAP GUIDANCE...WHICH SEEMS TO BE NAILING THE
FORECAST...THE 285K ISENTROPIC SURFACE INDICATES VERTICAL MOTION
TO CONTINUE UNDER SOUTH-SOUTHWEST FLOW UP THE SURFACE FOR SEVERAL
HOURS. THIS LIFT IS CENTERED ON TAYLOR-ADAMS COUNTIES THROUGH 10Z
BEFORE PULLING EAST.
HAVE UPDATED THE FORECAST FOR WI WITH WIDESPREAD DRIZZLE OVERNIGHT
AND FREEZING DRIZZLE NORTHEAST OF I-94. DO HAVE CONCERNS FOR ICING
OVERNIGHT NORTHEAST OF I-94 AND HAVE ISSUED AN SPS...UPDATED THE
GRAPHICAL WEATHER STORY...AND THE HAZ WEATHER OUTLOOK TO RAISE
AWARENESS.
UPDATE ISSUED AT 955 PM CST MON DEC 2 2013
A COUPLE OF THOUGHTS TO PASS ALONG QUICKLY. THE SNOW BAND ACROSS
CENTRAL WISCONSIN IS EXPECTED TO CONTINUE TO SHIFT
NORTHEAST...HOWEVER WI REMAINS UNDER THE INFLUENCE OF LIFT AND
SOME PRECIPITATION COULD CONTINUE TO FORM BEHIND THE BAND. OVER
THE PAST HOUR...KARX RADAR ECHOES DO STILL SHOW SOME OF THAT LIFT
AS A BAND FORMED ON THE MISS RIVER AND IS NOW ROTATING EAST BEHIND
THE INITIAL RA/SN BAND. UPSTREAM ICE CLOUD IS NOT ROBUST...AND THE
WARM ADVECTION REGION RUNNING FROM KMPX-KMSN ROUGHLY SEEMS THAT IT
COULD PROVIDE SOME LIFT IN THE LOW-LEVELS OVERNIGHT. SO...THE MAIN
CONCERN RIGHT NOW IS THE BAND SHIFTS NE AND THEN LOSS OF ICE CLOUD
WOULD ALLOW THE 2KM DEEP SURFACE-BASED SUPERCOOLED LIQUID LAYER TO
RESIDE WITH RAP/NAM/GFS AGREED ON -5 UB/S UPWARD MOTION. WITH
TEMPERATURES ALONG AND NORTHEAST OF I-94 NEAR OR BELOW FREEZING...THIS
COULD MEAN A FREEZING DRIZZLE PERIOD AFTER MIDNIGHT. WILL START TO
RAMP THE MESSAGE UP A BIT IN NEXT HOUR.
SECOND ITEM IS THE 03.00Z NAM HAS COME IN WITH A SOLUTION MORE
ALONG THE UKMET/ECMWF SOLUTIONS FOR A MORE SOUTHERN SURFACE LOW
PRESSURE TRACK WEDNESDAY AND A SNOWBAND OFF TO THE NORTHWEST. IT
IS LIKELY WE WILL START MOVING THE FORECAST TOWARD THAT EC/UKMET
SOLUTION OVERNIGHT. AT THIS TIME IT LOOKS LIKE THE MOST OF THE
PRECIPITATION WOULD FALL AS RAIN WITH A SNOW BAND WEST OF THE
FORECAST AREA. A MIXED PRECIPITATION TYPE ISSUE MAY BE IN THE
EQUATION...AND WILL EVALUATE OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 345 PM CST MON DEC 2 2013
FOR TONIGHT...A SHORT WAVE TROUGH WILL MOVE SLOWLY EAST INTO
WESTERN WISCONSIN THIS EVENING...AND THROUGH NORTHERN AND CENTRAL
WISCONSIN OVERNIGHT. THE PRECIPITATION ASSOCIATED WITH THIS
SYSTEM SEEMS TO BE TIED WITH THIS WAVE AND MODERATE TO STRONG 900
TO 800 MB FRONTOGENETIC BAND. THIS BAND ALONG WITH THE LATEST RAP
WAS USED TO TIME THE EASTWARD PROGRESSION OF THIS PRECIPITATION
THROUGH THE FORECAST AREA TONIGHT. SOUTH OF INTERSTATE 94...THE
SOUNDINGS SUGGEST THAT MUCH OF THE PRECIPITATION WILL BE MAINLY IN
THE FORM OF RAIN. WHILE THIS IS LIKELY THE CASE...THERE STILL
COULD BE SOME SNOW MIXING IN AT THE ONSET. NORTH OF INTERSTATE
94...THE SOUNDINGS ARE A BIT COLDER AND THEY SUGGEST THAT THE
PRECIPITATION WILL BE MORE SNOW THAN RAIN. MANY OF THE MODELS ARE
SUGGESTING THAT THE QPFS WILL RANGE FROM 0.10 TO 0.20 INCHES WILL
FALL NORTH OF INTERSTATE 94. HOWEVER THESE MODELS HAVE BEEN
OVERDOING THE PRECIPITATION TOTALS ACROSS SOUTHEAST MINNESOTA THIS
AFTERNOON...SO CONFIDENCE IS NOT OVERLY HIGH THAT THESE
PRECIPITATION AMOUNTS WILL BE REALIZED. AS A RESULT...LOWERED THE
PRECIPITATION AMOUNTS SOME. SNOW AMOUNTS WILL BE UP TO 2 INCHES
ACROSS NORTHERN CLARK AND TAYLOR COUNTIES TONIGHT. TOWARD MORNING
THERE IS SOME CONCERN THAT THERE MAY BE SOME LIGHT FREEZING RAIN
ACROSS THESE SAME AREAS AS WE LOSE THE ICE ALOFT BETWEEN 03.09Z
AND 03.15Z. HOWEVER THERE ARE A LOT OF QUESTIONS ON WHETHER ANY
PRECIPITATION WILL BE OCCURRING AT THIS TIME...SO DID NOT ISSUE A
WINTER WEATHER ADVISORY AT THIS TIME.
FROM LATE TUESDAY MORNING INTO THE AFTERNOON...285 TO 300K
ISENTROPIC LIFT AND WARM AIR ADVECTION INCREASES ACROSS THE AREA
AHEAD OF THE APPROACHING SHORT WAVE TROUGH AND SURFACE LOW.
OVERALL THE BEST 850 MB MOISTURE TRANSPORT LOOKS TO BE NORTH OF
THE INTERSTATE 90 CORRIDOR. IN ADDITION...THE WARM FRONT LOOKS
LIKE IT WILL BE CLOSE TO THIS CORRIDOR TOO. AS A RESULT...KEPT THE
HIGHEST PRECIPITATION CHANCES ACROSS THE NORTH. WOULD NOT BE
OVERLY SURPRISED TO SEE NORTHEAST IOWA AND SOUTHWEST WISCONSIN DRY
DURING THE AFTERNOON. THE 02.18Z NAM IS ALREADY SHOWING THIS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 345 PM CST MON DEC 2 2013
FROM TUESDAY NIGHT INTO THURSDAY...THE 02.00Z MODELS CONTINUE TO
STRUGGLE WITH THE STRENGTH OF A SHORT WAVE EJECTING OUT OF THE
NORTHERN PLAINS. WHILE THERE ARE COME SLIGHT DIFFERENCES IN TIMING
WITH THE GFS AND NAM...THEY ARE IN GOOD AGREEMENT THAT A STRONG
SHORT WAVE TROUGH WILL EJECT OUT OF THE WESTERN UNITED STATES LONG
WAVE TROUGH AND MOVE ACROSS NORTHERN MINNESOTA ON TUESDAY NIGHT
AND WEDNESDAY MORNING. THIS PUSHES AN ARCTIC COLD FRONT THROUGH
THE AREA ON WEDNESDAY MORNING...AND ALSO MOVES THE PRECIPITATION
OUT OF THE AREA BY LATE TUESDAY NIGHT. MEANWHILE THE ECMWF AND GEM
HAVE A MUCH WEAKER SHORT WAVE EJECTING OUT OF THE LONG WAVE
TROUGH DURING THE SAME TIME PERIOD. AS A RESULT...THE UPPER AIR
FLOW REMAINS SOUTHWESTERLY AND THIS SLOWS THE EASTWARD PROGRESS OF
THE ARCTIC COLD FRONT THROUGH THE FORECAST AREA. AS A RESULT THE
TEMPERATURES ARE MUCH WARMER FROM WEDNESDAY INTO THURSDAY MORNING.
IT ALSO ALLOWS ANOTHER BAND OF PRECIPITATION TO MOVE ACROSS THE
AREA FROM WEDNESDAY INTO WEDNESDAY NIGHT ALONG THE COLD FRONT.
UNFORTUNATELY...ALL OF THESE MODELS HAVE BEEN VERY CONSISTENT WITH
THEIR FORECAST SCENARIOS...SO THE FORECAST CONFIDENCE REMAINS
UNUSUALLY LOW FOR THIS TIME PERIOD. SINCE THERE WAS NO CLEAR
CONSENSUS...THE FORECAST WAS TRENDED TOWARD A BLEND OF ALL OF
THEM. WHILE THERE IS A POTENTIAL OF 2 TO 4 INCHES OF SNOW ACROSS
NORTHERN CLARK AND TAYLOR COUNTIES...THE FORECAST CONFIDENCE WAS
TOO LOW TO EVEN ISSUE A WINTER STORM WATCH FOR THIS TIME PERIOD.
FURTHER NORTHWEST WHERE THERE IS A BIT MORE CONSENSUS...A WINTER
STORM WATCH WAS ISSUED.
FROM FRIDAY INTO SATURDAY...THE FORECAST CONFIDENCE IS STILL NOT
THAT HIGH ON THE TEMPERATURES FOR THIS TIME PERIOD. UNLIKE THE
PAST COUPLE OF DAYS...THERE IS NOW A STRIATION IN THE 850 MB
TEMPERATURES ACROSS THE FORECAST AREA. TEMPERATURES ACROSS THE
AREA RANGE FROM -14C ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN
TO -20C IN NORTH CENTRAL WISCONSIN. IN ADDITION...THERE CONTINUES
TO BE QUESTIONS ON WHETHER THERE WILL BE ANY SNOW COVER ACROSS
MUCH OF THE FORECAST AREA. IN AREAS WHICH DO NOT HAVE SNOW
COVER...BOTH HIGHS AND LOW TEMPERATURES WILL BE 10 TO 15 DEGREES
WARMER THAN AREAS /LIKELY NORTH OF INTERSTATE 94/ WHICH HAVE AT
LEAST 1 INCH OF SNOW ON THE GROUND. DUE TO THIS...WENT MORE WITH
THE CONSENSUS OF HIGH TEMPERATURES IN THE SINGLE DIGITS NORTH OF
THE INTERSTATE 94 CORRIDOR AND IN THE TEENS ACROSS THE REMAINDER
OF THE AREA. LOW TEMPERATURES WILL BE IN THE NEGATIVE SINGLE
DIGITS NORTH OF INTERSTATE 94 AND BE IN THE POSITIVE SINGLE
DIGITS ACROSS THE REMAINDER OF THE AREA.
ON SUNDAY AND SUNDAY NIGHT...WEAK WARM AIR ADVECTION AND 275-285K
ISENTROPIC LIFT AHEAD OF AN APPROACHING SHORT WAVE WILL LOWER
CONDENSATION PRESSURE DEFICITS TO LESS THAN 30 MB. THIS SHOULD
RESULT IN THE POTENTIAL FOR SOME LIGHT SNOW OR FLURRIES. DUE TO
THIS...A 15 TO 24 PERCENT CHANCE OF LIGHT SNOW WAS ADDED TO THE
FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1138 PM CST MON DEC 2 2013
STATIONARY FRONT REMAINS PARKED TO THE WEST OF THE TAF SITES WHICH
CONTINUES TO PROVIDE A GOOD ENVIRONMENT FOR LOW CEILINGS. HAVE PUT
A SMALL DIURNAL TREND IN OVERNIGHT WITH SOME LOWERING CIGS/VSBYS
NEAR SUNRISE...BEFORE LIFTING WITH A BIT OF WARMING TUESDAY.
HOWEVER...EDGE TO CLOUDS IS JUST WEST OF KRST AND THIS MAY GET
CLOSE OR WORK IN AT TIMES AT KRST. THIS IS NOT IN THE CURRENT
FORECAST...BUT MAY OCCUR.
HAVE GOOD LIFT OCCURING AT AND EAST OF KLSE OVERNIGHT WHICH WILL
CAUSE DZ TO BE AROUND FOR SEVERAL HOURS OVERNIGHT. TEMPERATURES
WILL REMAIN ABOVE FREEZING SO ICING SHOULD NOT BE AN ISSUE AT
KLSE. ANOTHER PERIOD OF LIFT COMING IN LATE TUESDAY AND INTO
TUESDAY NIGHT WILL PROLONG THE LOW MVFR OR IFR CONDITIONS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BAUMGARDT
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS TUCSON AZ
935 PM MST WED DEC 4 2013
.SYNOPSIS...A STRONG STORM SYSTEM MOVING THROUGH THE WESTERN UNITED
STATES WILL BRING A CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW TO
SOUTHEAST ARIZONA THROUGH THURSDAY. THIS SYSTEM WILL ALSO BRING MUCH
COOLER TEMPERATURES...WITH WIDESPREAD FREEZING TEMPERATURES ACROSS
ALL OF SOUTHEAST ARIZONA FRIDAY MORNING. ANOTHER STORM SYSTEM WILL
BRING GUSTY WINDS...A CHANCE OF THE PRECIPITATION AND A
REINFORCEMENT OF COLDER AIR LATE THIS WEEKEND.
&&
.DISCUSSION...SCATTERED SHOWERS PRODUCING GENERALLY A FEW HUNDREDTHS
OF AN INCH DURING THE PAST 1-3 HOURS ONGOING FROM THE NWRN PORTION
OF THE TUCSON METRO AREA WESTWARD AND NORTHWESTWARD INTO CENTRAL
PIMA COUNTY AND SE PINAL COUNTY. ALTHOUGH CELL MOVEMENT HAS BEEN
NEWD...AREAL COVERAGE CONTINUES TO GRADUALLY EXPAND EWD. RUC HRRR
CONTINUES TO EXPAND THE COVERAGE OF PRECIP ACROSS MUCH OF SE AZ
DURING THE NEXT SEVERAL HOURS.
THUS...EXPECT SCATTERED TO NUMEROUS SHOWERS THE REST OF TONIGHT
MAINLY FROM THE TUCSON METRO AREA EWD/SWD. FOR NOW HAVE MAINTAINED
ISOLATED SHOWERS ACROSS WRN PIMA COUNTY...ALTHOUGH SATELLITE/RADAR
TRENDS SUGGEST THIS ACTIVITY MAY BE OVERDONE. PRECIP TO CONTINUE
ACROSS MUCH OF THE AREA THURSDAY MORNING...THEN PRECIP TO DECREASE
FROM NORTHWEST-TO-SOUTHEAST THUR AFTERNOON. SNOW LEVELS BY MIDDAY
THUR ARE EXPECTED TO RANGE FROM ABOUT 4000 FEET ACROSS THE WHITE
MOUNTAINS TO ABOUT 6500 FEET IN FAR SERN SECTIONS.
THE OFFICIAL FORECAST WAS UPDATED TO DECREASE MIN TEMPS ABOUT 2-4
DEGS FROM TUCSON WWD THE REST OF TONIGHT. OCCASIONALLY GUSTY SLY
WINDS SHOULD CONTINUE TONIGHT EAST AND SOUTH OF TUCSON. HOWEVER...
WIND SPEEDS WILL BE WELL BELOW WIND ADVISORY CRITERIA. GUSTY
SOUTHWEST TO WEST WINDS ARE ON TAP EAST AND SOUTH OF TUCSON THUR.
MARKEDLY LIGHTER WINDS WILL OCCUR FROM TUCSON WWD THUR. EXPECT MUCH
COOLER TEMPS THUR...WITH HIGH TEMPS PARTICULARLY FROM TUCSON WWD
NEARLY 15 DEGS F COOLER VERSUS TODAY.
PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL.
&&
.PREV DISCUSSION...THE UPPER PATTERN IS DEFINED BY A HIGH AMPLITUDE
UPPER RIDGE IN THE EASTERN PACIFIC...AND A LONGWAVE TROUGH ACROSS
THE WESTERN STATES. SHORTWAVE ENERGY MOVING SOUTH ALONG THE
CALIFORNIA COAST WILL ROTATE INTO THE SOUTHERN EDGE OF THIS TROUGH
BEFORE IT TRACKS ACROSS THE AREA TONIGHT AND THURSDAY. THE TIGHT
GRADIENT OUT AHEAD OF THIS TROUGH HAS RESULTED IN BREEZY TO WINDY
CONDITIONS...ESPECIALLY TO THE EAST AND SOUTH OF TUCSON. SURFACE
OBSERVATIONS IN KDUG INDICATE SUSTAINED WINDS IN THE 25 TO 30 MPH
RANGE WITH GUSTS TO 45 MPH. A WIND ADVISORY IS IN EFFECT TO THE EAST
UNTIL 8 PM MST THIS EVENING. THE LATEST MODEL GUIDANCE STILL
INDICATES 45 KT FLOW ACROSS COCHISE AT 06Z TONIGHT. THIS USUALLY
MEANS THAT LOCALIZED AREAS NEAR THE HUACHUCA MOUNTAINS WILL CONTINUE
TO EXPERIENCE STRONG AND GUSTY WINDS WELL INTO THE OVERNIGHT HOURS.
ACCORDING TO THE LATEST SURFACE OBSERVATIONS...THE SOUTHERN TIP OF
THE SURFACE COLD FRONT ASSOCIATED WITH THIS SYSTEM IS CURRENTLY
POSITIONED ACROSS CENTRAL PIMA COUNTY EXTENDING INTO NW PINAL
COUNTY. AT 230 PM MST...KEMX RADAR JUST BEGINNING TO INDICATE SHOWERS
DEVELOPING ACROSS THE TOHONO OODHAM NATION. THE HRRR AND UNIVERSITY
OF ARIZONA WRF MODELS INDICATE THAT THE COLD FRONT WILL PUSH WEST
INTO TUCSON BY 5 PM THIS AFTERNOON WITH PCPN BEGINNING TO EXPAND AND
ENHANCE AS IT MOVES FARTHER EAST. EXPECT SHOWERS TO BECOME MORE
NUMEROUS THIS EVENING WITH THE MAJORITY OF THE PCPN AFFECTING THE
CWA OVERNIGHT INTO THURSDAY MORNING. MOISTURE SOMEWHAT LIMITED WITH
THIS SYSTEM AND STILL EXPECT ONLY A TENTH TO A THIRD INCH WITH MAYBE
A HALF INCH IN THE MOUNTAINS. THIS TRANSLATES INTO SNOWFALL AMOUNTS
JUST BELOW ADVISORY CRITERIA. IT IS POSSIBLE THAT SOME OF THE
HIGHEST PEAKS MAY BARELY HIT LOW END SNOW ADVISORY CRITERIA...BUT IT
WILL NOT BE WIDESPREAD ENOUGH TO WARRANT AN ADVISORY.
THE MAIN ISSUE WITH THIS SYSTEM IS NOT THE WIND OR THE PCPN...BUT
THE TEMPERATURES. COLD AIRMASS MAKING ITS WAY SOUTH WILL BRING THE
FIRST WIDESPREAD FREEZING TEMPERATURES TO THE LOWER DESERTS FROM
TUCSON WEST. HAVE DECIDED TO ISSUE A FREEZE WARNING FOR FRIDAY
MORNING TO GET THE WORD OUT TO PROTECT PEOPLE...PETS...PIPES AND
PLANTS.
ANOTHER STRONG WEATHER SYSTEM WILL MAKE ITS WAY SOUTH INTO ARIZONA
THIS WEEKEND. THE ECMWF IS MUCH COLDER AND THUS MORE AGGRESSIVE THAN
THE GFS BRINGING PCPN AND ANOMALOUSLY COLDER TEMPS. INCREASED POPS AND
LOWERED TEMPS SAT NIGHT INTO MONDAY TO REFLECT THIS TREND.
&&
.AVIATION...VALID THRU 06/00Z.
SCATTERED SHOWERS AND HIGHER TERRAIN SNOW SHOWERS GENERALLY FROM
KTUS VICINITY EWD/SWD THRU THURSDAY MORNING...THEN PRECIPITATION
ENDING FROM NORTHWEST-TO-SOUTHEAST BY THURSDAY EVENING. CLOUD DECKS
THRU THURSDAY AFTERNOON GENERALLY 3-6K FT AGL. AREAS MVFR CIGS/VSBYS
THRU THURSDAY AFTERNOON ESPECIALLY NEAR HIGHER TERRAIN NORTH TO
NORTHEAST OF KTUS. CLEAR SKIES FROM WEST-TO-EAST WILL OCCUR THURSDAY
EVENING. SURFACE WIND EAST AND SOUTH OF KTUS THRU THURSDAY EVENING
WLY 12-18 KTS WITH GUSTS TO 30 KTS. SURFACE WIND KTUS VICINITY WWD/
NWWD GENERALLY LESS THAN 10 KTS. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.
&&
.FIRE WEATHER...LOW PRESSURE TROUGH OVER THE WEST IS EXPECTED TO
REMAIN THROUGH THE FIRST PART OF NEXT WEEK. THE STRONG WINDS
ASSOCIATED WITH THIS TROUGH WILL SUBSIDE AROUND MIDNIGHT AND MUCH
COLDER AIR WILL ADVECT INTO THE AREA THURSDAY. TEMPERATURES WILL
DROP ABOUT 15 DEGREES BELOW AVERAGE LATE THURSDAY AND CONTINUE
THROUGH THE WEEKEND. MOISTURE WITH THIS TROUGH IS LIMITED...ALTHOUGH
MANY AREAS WILL SEE LIGHT PRECIPITATION AMOUNTS. A SECOND STORM
SYSTEM WILL DROP INTO THIS TROUGH LATE SATURDAY FOR A CHANCE OF
VALLEY RAIN AND MOUNTAIN SHOWERS...ALONG WITH REINFORCING THE COLDER
TEMPERATURES INTO EARLY NEXT WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING FROM 10 PM THURSDAY TO 10 AM MST FRIDAY FOR
AZZ501>506.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1142 PM MST WED DEC 4 2013
.UPDATE...
ISSUED AT 1142 PM MST WED DEC 4 2013
CANCELLED THE REMAINING WINTER STORM WARNINGS OVER THE CENTRAL AND
SOUTHERN MOUNTAINS AS THERE WAS LITTLE INDICATION THAT ANYTHING
MORE THAN A FEW LIGHT FLURRIES IN PROGRESS ACROSS THE REGION.
NEITHER THE RAP13 NOR THE HRRR INDICATED ANY ADDITIONAL QPF DURING
THE NIGHT. IN ADDITION...REDUCED POPS DURING THE REMAINDER OF THE
NIGHT TO BETTER REFLECT LATEST SHORT RANGE GUIDANCE. HOWEVER...
WILL HOIST A DENSE FOG ADVISORY FOR A PORTION OF THE I-70 CORRIDOR
IN RESPONSE TO A REPORT FROM A TRAINED SPOTTER WHO OBSERVED AREAS
OF DENSE FOG IMPACTING THE INTERSTATE FROM NEWCASTLE TO SILT.
UPDATE ISSUED AT 613 PM MST WED DEC 4 2013
ALLOWED THE WARNING ALONG THE I-70 CORRIDOR FROM GLENWOOD SPRINGS
EASTWARD TO EXPIRE. REMAINING HIGHLIGHTS WILL STAY IN EFFECT AS
ASPEN...MONTROSE AND SOME POINTS IN BETWEEN CONTINUE TO REPORT
SNOW AT THIS HOUR. A BUSY DAY!
UPDATE ISSUED AT 514 PM MST WED DEC 4 2013
LOCAL WEBCAMS SHOW SUN PEAKING THROUGH THE CLOUDS OVER SOUTHERN
COLORADO. WEBCAMS FACING NORTH AND WEST OF PAGOSA SPRINGS SHOW
PLENTY OF CLEARING SO DROPPED THE HIGHLIGHTS FOR THOSE TWO AREAS.
REMAINING WARNINGS WILL STAY IN PLACE.
UPDATE ISSUED AT 455 PM MST WED DEC 4 2013
SATELLITE IMAGERY SHOWING DEFINITE CLEARING FROM THE ROAN/TAVAPUTS
NORTH AND ALSO AREAS TO THE W AND SW. WITH THAT IN MIND...DROPPED
THE WARNINGS AND ADVISORIES IN THOSE AREAS. KEPT REMAINING
WARNINGS AND ADVISORIES IN PLACE BUT WILL KEEP AN EYE OUT SINCE
BEST SUPPORT CONTINUES TO SHIFT SOUTHWARD. ANTICIPATE THE
HIGHLIGHTS IN DURANGO AND PAGOSA SPRINGS WILL BE COMING DOWN EARLY
TOO BUT WILL KEEP AN EYE ON SATELLITE AND WEBCAMS BEFORE DOING
ANYTHING.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 341 PM MST WED DEC 4 2013
THE STRONG AND COLD WINTER STORM WILL BE ON ITS WAY OUT TONIGHT AS
THE CORE OF THE 140-150 KT UPPER JET LIFTS AWAY TO THE NORTHEAST.
LOOKS LIKE THE COLD FRONT HAS JUST EXITED ARCHULETA COUNTY TO THE
SOUTHEAST AS TEMPS AT PAGOSA WERE NOW FALLING. HAVE PRUNED SOME MORE
WINTER HIGHLIGHTS AS CLEARING CONTINUES TO WORK IN FROM THE W AND
NW. LEFT THE CO MTNS AND THE CENTRAL AND SOUTHWEST CO VALLEYS UNDER
WINTER WARNINGS/ADVISORIES AS PRECIPITATION IS EXPECTED TO PERSIST
INTO THE EVENING IN THESE AREAS...ALTHOUGH CONCERNED THAT DURANGO
AND PAGOSA ZONES MAY HAVE TROUBLE REACHING CRITERIA.
WHILE SOME CLEARING OBSERVED LATE TODAY IN NW CO AND NE UT...EXPECT
SOME LOW CLOUDS AND PATCHY FOG TO FILL IN MANY OF THESE VALLEYS
LATER TONIGHT AS INVERSIONS SET UP. THE ARCTIC-TINGED AIR WILL
RESULT IN VERY COLD TEMPS TONIGHT AND AGAIN THURSDAY NIGHT. WITH
WIDESPREAD AND FRESH SNOW COVER...DAYTIME RECOVERY ON THURSDAY WILL
BE RESTRICTED AS THE EXTREMELY COLD AIR MASS SETTLES IN. A WEAKER
AND DRIER TROUGH MOVES ACROSS ON THURSDAY FOR A COUPLE INCHES OF
SNOW OVER THE SAN JUANS THURSDAY AFTERNOON/EVENING...WITH A CHANCE OF
SNOW SHOWERS ELSEWHERE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 341 PM MST WED DEC 4 2013
THE DOOR TO THE ARCTIC REMAINS OPEN THROUGH MONDAY. EXPECT BRISK
SHOTS OF FRESH FRIGID AIR AND SOME NEW SNOW. BY TUESDAY A RIDGE
BUILDING OVER THE WEST WILL CUT OFF THE ARCTIC EXPRESS FOR THIS
REGION. SO THEN VALLEY INVERSIONS WILL LIKELY SETUP FOR CONTINUED
FRIGID CONDITIONS.
FRIDAY THE BROAD WESTERN TROUGH IS RELOADING. THE NEXT OPEN
ALASKAN DISTURBANCE IS DIVING DUE SOUTH THROUGH THE PACIFIC NW
AND INTO THE WESTERN GREAT BASIN FRIDAY NIGHT. THIS BACKS THE
UPPER WINDS TO WEST THEN SOUTHWEST. 700MB TEMPERATURE CLIMBS TO
-12/SOUTH AND -16/NORTH...WHILE THE 300-500MB LAYER STARTS TO
COOL. THIS WILL ASSIST WITH SNOWFALL PRODUCTION BY RAISING THE
SNOW PRODUCTION LAYER UP TO THE MTN TOP LAYER AND STEEPENS THE
LAPSE RATE. THE TROUGH PASSAGE OCCURS EARLY SUNDAY MORNING WITH
BEST SNOW ACCUMULATION SHIFTING FRONT SW TO NW (SKI) SLOPES. SNOW
PERSISTS OVER THE NW COLORADO MTNS INTO MONDAY AS THE H5 -40C COLD
CORE BRUSHES THE NORTH. THIS IS IMPRESSIVELY COLD AIR AND WILL
LIKELY SCOUR OUT ANY WEAK INVERSIONS THAT HAVE FORMED. HIGHLIGHTS
ARE QUITE POSSIBLE WITH THIS TROUGH PASSAGE.
BEGINNING MONDAY AFTERNOON THE EASTERN PACIFIC RIDGE PROGRESSES
INLAND SOMEWHAT. THIS BRINGS A QUICK MODIFICATION TO THE COLD MID-
UPPER PORTIONS OF THE ATMOSPHERE. THIS WILL LIKELY LOCK THE SNOW
COVERED VALLEYS INTO WHAT WILL BECOME STRONG AND PERSISTENT
INVERSIONS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 942 PM MST WED DEC 4 2013
SNOW WILL CONTINUE TO WIND DOWN DURING THE NEXT FEW HOURS. HOWEVER
SOME AREAS OF SNOW WILL PERSIST LATE TONIGHT ALONG OROGRAPHICALLY
FAVORED SLOPES AND DRAINAGES. TAF SITES THAT MAY CONTINUE TO SEE
SNOW AT TIMES UNTIL AROUND 09Z...INCLUDE KASE/KMTJ/KTEX. LOCAL
MOUNTAIN OBSCURATIONS WILL ALSO BE EXPECTED. MOUNTAIN SNOW WILL
INCREASE A LITTLE THURSDAY AFTERNOON...05/19Z-06/00Z...AS THE NEXT
WAVE PASSES. IN ADDITION TO THE LINGERING SNOW...PATCHY FOG WILL
FORM IN MANY VALLEY LOCATIONS LATE TONIGHT THROUGH THURSDAY
MORNING...AND MAY IMPACT AREA TAF SITES.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...DENSE FOG ADVISORY UNTIL 9 AM MST THURSDAY FOR COZ007-008.
UT...NONE.
&&
$$
UPDATE...NL
SHORT TERM...JAD
LONG TERM...JOE
AVIATION...EH
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
300 AM EST Thu Dec 5 2013
...Unseasonably warm weather to continue...
.NEAR TERM [Through Today]...
Northwest parts of our forecast area (roughly DTS-DHN) have been
experiencing a relatively persistent rain band through the evening
and into the early part of the overnight hours. Looking at surface
observations, there is a subtle boundary near the Florida
Panhandle coast. Southerly winds with higher thetae values over
the water stand in contrast to backed winds and lower thetae
values over the land areas. North of the boundary, there appears
to be a narrow band of stronger southwesterly winds in the 1-2km
AGL layer (around 30 knots or so). It is in this region of more
focused moisture transport and isentropic ascent that the rain
band has been focused. Rainfall rates have not been trivial - dual
pol estimates from EOX and EVX are around 0.5-1.0"/hr in narrow
bands of training echoes. QPF and PoPs were increased for the
06-12z period in these areas earlier this evening (around 05z).
The HRRR and other CAM output do show a continuation of rain
showers in the NW third of our area through the day today, but the
rain is of a more scattered nature. Thus, PoPs were pared back for
the 12-00z timeframe, but maintained due to continued isentropic
ascent in nearly saturated layers.
Highs were adjusted to be close to yesterday: mid 70s in cloudier
areas in our northwest, and around 80 elsewhere. The record high in
Tallahassee today is 81, which is what we are forecasting so we
should get close to record highs barring any unforseen cloud cover.
Finally, there is the issue of fog during the pre-dawn and early
morning hours. A Dense Fog Advisory was issued earlier as fog was
causing visibility to decrease at many observing sites, and when the
visibility in Tallahassee was around 1/8 mile. Since then, a
mid-level cloud deck has caused fog to dissipate and redevelop, with
substantial fluctuations in visibility. However, with each new set
of observations that comes in, there is usually at least one or two
sites that are down around 1/4 mile. Therefore, the advisory will be
maintained as is, but will be re-evalulated closer to sunrise.
&&
.SHORT TERM [Tonight Through Saturday]...
Strong upper ridge will remain in place over Florida tonight into
Saturday, keeping temperatures well above normal and in sharp
contrast to the record cold temperatures in the plains states.
Boundary between the airmasses will stretch from far northeast
Alabama into central Louisiana tonight, and will slowly push
southeastward Friday into Saturday. Ahead of the front (away from
the center of the upper ridge), isolated showers will be possible
across SE Alabama tonight and Friday. Very warm temperatures are
expected through Friday night, with highs in the lower 80s and
lows generally in the 60s. The highs on Friday will be very close
to record temperatures for the date.
The cold front will edge into the forecast area on Saturday before
stalling and lifting back to the north Saturday night. This will
lead to a wide range of temperatures across the region, with
temperatures forecast to hold steady in the 50s in southeast
Alabama, while upper 70s are expected south and east of the
boundary.
Fog will continue to be of concern over the next few nights.
However, the more southeasterly direction expected tonight is not
as favorable a trajectory for advecting the moist Gulf airmass
across the cool Apalachee Bay waters. By Friday night, the flow is
expected to be weaker, which will also limit the potential for
advection fog. So while widespread fog is expected, the potential
for widespread dense fog is much less certain.
&&
.LONG TERM [Saturday Night through Wednesday]...
The cold front will push back north as a warm front Saturday night,
meaning that our area never gets into the deeper moisture or lift
behind the front. The drier return flow on Sunday is short-lived,
as a second much stronger cold front pushes through the area late
Monday night into early Tuesday. This front has the upper support
to push all the way south across the FL peninsula, putting AL, GA,
and northern FL well into the cold air. As a result, the very warm
temperatures of the past week could drop by 15 to 20 degrees
behind the front on Tuesday and Wednesday, with readings in the
50s in SE Alabama and SW Georgia to the 50s and lower 60s across
northern FL.
Precipitation will generally be scattered through the period with
a chance of thunderstorms along and ahead of the first front
Saturday and again with the much more vigorous front on Monday.
&&
.AVIATION [Through 06Z Friday]...
Current conditions are varying widely early this morning due to a
scattered deck of mid-level clouds between 7000-10000 feet. This is
causing fog to dissipate and redevelop with flight categories at
some of the terminals varying between VFR and LIFR in the space of a
couple hours. The bottom line is that when mid-level cloud cover
thins a bit, there is a good chance of IFR/LIFR with fog through
14-15z this morning at TLH, ABY, and VLD, and perhaps also at ECP. A
band of rain showers near DHN should prevent much fog there although
CIGS should be in the IFR range. We expect VFR after 15z, with
another round of fog developing tomorrow evening.
&&
.MARINE...
Light to moderate southeasterly flow will continue over the
coastal waters through Friday night as high pressure remains
anchored off the east coast. A front will slide into the western
waters on Saturday before lifting back to the north Saturday
night, with southeasterly flow continuing into early next week.
&&
.FIRE WEATHER...
Red flag conditions are not expected the next several days. Dense
fog is likely in spots over the next several nights with poor
mixing and light winds.
&&
.HYDROLOGY...
Isolated to scattered showers will be possible over the western
half of the forecast area through Saturday. Total rainfall amounts
should generally remain below 1 inch, which will lead to only
minimal impacts on area rivers and streams.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 81 59 78 63 75 / 20 10 10 10 30
Panama City 75 65 76 65 70 / 30 10 10 30 30
Dothan 76 63 80 59 62 / 40 20 10 30 50
Albany 79 61 81 64 69 / 30 10 10 20 40
Valdosta 81 61 81 62 78 / 20 10 10 10 20
Cross City 81 59 81 59 79 / 10 10 10 10 10
Apalachicola 76 64 74 66 73 / 10 10 10 10 20
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...DENSE FOG ADVISORY until 10 AM EST /9 AM CST/ this morning for
Coastal Dixie-Coastal Franklin-Coastal Gulf-Coastal
Jefferson-Coastal Taylor-Coastal Wakulla-Gadsden-Inland
Dixie-Inland Franklin-Inland Gulf-Inland Jefferson-Inland
Taylor-Inland Wakulla-Lafayette-Leon-Liberty-Madison.
GA...DENSE FOG ADVISORY until 10 AM EST this morning for Baker-Ben
Hill-Berrien-Brooks-Calhoun-Colquitt-Cook-Decatur-
Dougherty-Grady-Irwin-Lanier-Lee-Lowndes-Miller-Mitchell-
Seminole-Terrell-Thomas-Tift-Turner-Worth.
AL...None.
GM...DENSE FOG ADVISORY until 10 AM EST this morning for Apalachee
Bay or Coastal Waters From Keaton Beach to Ochlockonee
River Fl out to 20 Nm-Coastal Waters From Ochlockonee
River to Apalachicola Fl out to 20 Nm-Coastal waters from
Suwannee River to Keaton Beach out 20 NM-Waters from
Suwannee River to Apalachicola FL from 20 to 60 NM.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Camp
LONG TERM...Hollingsworth
AVIATION...Lamers
MARINE...Camp
FIRE WEATHER...Lamers
HYDROLOGY...Camp
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
425 AM EST THU DEC 5 2013
.SHORT TERM /TODAY THROUGH FRIDAY/...
SHORT TERM MODELS ARE IN GOOD AGREEMENT...BUT CONTINUE TO HAVE
ISSUES WITH IMPULSES MOVING THROUGH THE UPPER LEVEL FLOW WHICH ARE
PRODUCING AREAS OF RAIN ACROSS THE FORECAST AREA. UPPER LEVEL
RIDGING BUILDS OVER FL/SE GA AS BROAD LONG WAVE TROUGH MOVES ACROSS
THE DESERT SOUTHWEST. THE SUBTLE IMPULSES MAKE IT HARD TO PINPOINT
EXACT TIMING OF RAIN TRENDS. THE RAP HAS HAD A GOOD HANDLE ON THE
AREA OF RAIN MOVING ACROSS PORTIONS OF CENTRAL GA AND LEANED HEAVILY
TOWARD RAP SOLUTION IN THE NEAR TERM. AREA OF RAIN WILL MOVE VERY
CLOSE TO ATLANTA BUT MAINLY IMPACT SOUTH AND EAST PORTIONS OF THE
METRO AREA IN THE EARLY PORTIONS OF THE MORNING RUSH HOUR...
IMPACTING AREAS NORTH OF MACON AND ATHENS THROUGH 8AM BEFORE EXITING
THE FORECAST AREA. EARLIER AREA OF RAIN ALLOWED ATMOSPHERE OVER
NORTHEAST GA TO MIX..WINDS HAVE SHIFTED OUT OF THE SOUTH AND
SOUTHWEST AND VISIBILITIES HAVE INCREASED TO 1-2 MILES. WHILE
PATCHES OF DENSE FOG WILL BE POSSIBLE TOWARD MORNING WIDESPREAD
DENSE FOG IS NOT EXPECTED AND WILL DROP THE DENSE FOG ADVISORY AT
THIS TIME BUT CONTINUE TO MONITOR THE SITUATION.
SURFACE FRONT NEAR ARKLATEX WILL SLOWLY TREK ACROSS THE GULF COAST
STATES TODAY WITH GOOD GULF MOISTURE SPREADING AHEAD OF THE FRONT
ESPECIALLY INTO WESTERN PORTIONS OF FORECAST AREA. MODELS CONTINUE
TO SHOW MUCAPE OF 400-900 NORTH OF A LINE FROM AMERICUS TO
MILLEDGEVILLE. BEST SHEAR AXIS REMAINS WEST OF FORECAST AREA...
HOWEVER ENOUGH FOR ISOLATED THUNDER ACROSS NORTH AND WEST GA
18-06Z. SEVERE IS UNLIKELY AT THIS TIME BUT LATER SHIFTS WILL
CONTINUE TO MONITOR. FRONT STALLS OR DRIFTS SLOWLY SOUTHEAST ACROSS
FORECAST AREA THROUGH FRIDAY. MODELS SHOW AN INCREASED AXIS OF
INSTABILITY ONCE AGAIN FRIDAY AFTERNOON...ENOUGH TO WARRANT ISOLATED
THUNDER ONCE AGAIN
GUIDANCE TEMPERATURES LOOK IN LINE AND HAVE TAKEN A BLEND OF MAV AND
MET...LEANING TOWARD WARMER GUIDANCE EACH DAY. OVERNIGHT LOWS
TONIGHT WILL BE CLOSE TO BREAKING SOME OF THE RECORD HIGH MINIMUM
TEMPERATURES AT THE CLIMATE STATIONS.
ATWELL
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A WET AND UNSETTLED PATTERN WILL CONTINUE UNTIL TUESDAY.
MODELS SIMILAR WITH A SLOW MOVING COLD FRONT OVER N GA FORECAST TO
MOVE TO CENTRAL GA AND S DURING THE DAY SATURDAY. HIGHEST RAIN
CHANCES ACROSS N GA FRIDAY NIGHT AND OVER THE FORECAST AREA IN
GENERAL ON SATURDAY AS A MOIST SW FLOW ALOFT MOVES OVER THE ENTIRE
AREA.
GFS/EUROPEAN SIMILAR WITH COLD AIR DAMMING SETTING UP SUNDAY NIGHT
AND CONTINUING MONDAY. RAIN AND DRIZZLE CAN BE EXPECTED FOR MUCH
OF THE AREA...WITH THE SMALLEST CHANCES OVER THE SOUTHERN PORTION
OF CENTRAL GA.
GFS/EUROPEAN SIMILAR WITH BRINGING ANOTHER COLD FRONT INTO N GA
SUNDAY NIGHT AND INTO CENTRAL GA ON MONDAY THEN EXITING THE AREA
MONDAY NIGHT. HIGHEST RAIN CHANCES WILL CONTINUE OVER N AND PORTIONS
OF CENTRAL GA UNTIL TUESDAY WHEN PRECIP CHANCES WILL END. SOME
MUCAPE ASSOCIATED WITH THE COLD FRONT AND CONDITIONS WILL NEED TO BE
MONITORED FOR THE POTENTIAL OF STRONG TO SEVERE STORMS SUNDAY NIGHT
INTO MONDAY.
LARGE VARIATIONS OF TEMPERATURES CAN BE EXPECTED FROM N TO S UNTIL
MONDAY NIGHT AND TUESDAY WHEN THE PLUNGE TO COLDER TEMPERATURES
ACROSS THE AREA OCCURS.
BDL
&&
.CLIMATE...
RECORDS FOR 12-05
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAHN 77 1977 39 1984 59 1912 20 1935
1971 1886
1905
KATL 75 1998 33 1895 60 1998 20 1899
1977
KCSG 82 1977 45 1984 63 1994 26 1960
1957
KMCN 80 1977 44 1945 64 1912 22 2000
1901
RECORDS FOR 12-06
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAHN 77 1998 37 1992 59 1912 20 1937
1962
KATL 75 2001 25 1937 57 2011 14 1937
1998
1912
KCSG 78 1951 42 1992 63 2011 24 1962
1962
KMCN 78 1924 33 1937 63 1912 20 1937
&&
.AVIATION...
06Z UPDATE...
TAF SITES ARE A MIX IFR/MVFR WITH PATCHY LIFR BEGINNING TO
DEVELOP. BASED UPON RAINFALL EXPECT ALL TAF SITE LIFR/IFR BY
DAYBREAK WITH CIGS BELOW 010 AND VISIBILITIES DROPPING TO 1SM.
COULD SEE PATCHY VISIBILITIES TO 1/2SM BUT DO NOT HAVE IT IN TAF
SITE AT THIS TIME. ANOTHER AREA OF LIGHT RAIN WILL IMPACT
CSG/MCN/AHN BUT BASED UPON CURRENT RADAR LOOP SHOULD STAY EAST OF
ATL. WINDS ARE MAINLY SOUTH WITH ATL MAINLY SOUTHWEST...WIND
SPEEDS SHOULD BE LIGHT 7KTS OR LESS.
//ATL CONFIDENCE...06Z UPDATE...
LOW TO MEDIUM CONFIDENCE ON WIND DIRECTION STAYING OUT OF
SOUTHWEST.
MEDIUM CONFIDENCE IN VISIBILITY/CIGS/WEATHER BASED UPON
TIMING OF LIGHT RAIN/FOG AND LOWERING CIGS.
MEDIUM TO HIGH CONFIDENCE IN WIND SPEEDS.
ATWELL
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 60 76 56 / 50 50 30 50
ATLANTA 72 62 74 49 / 50 50 70 80
BLAIRSVILLE 66 60 66 46 / 60 80 90 100
CARTERSVILLE 72 63 75 45 / 50 60 90 100
COLUMBUS 76 63 79 55 / 50 40 20 60
GAINESVILLE 67 61 72 51 / 50 60 70 80
MACON 76 61 80 60 / 50 20 20 40
ROME 74 62 74 45 / 60 70 100 100
PEACHTREE CITY 72 64 77 49 / 50 40 60 80
VIDALIA 76 62 81 63 / 50 20 10 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ATWELL
LONG TERM....BDL
AVIATION...ATWELL
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
345 AM CST THU DEC 5 2013
.DISCUSSION...
345 AM CST
MAIN FORECAST FOCUS IS ON COLDER TEMPERATURES WHICH WILL AFFECT THE
MIDWEST THROUGH THE PERIOD...AND THE POTENTIAL FOR SOME LIGHT SNOW
MAINLY SOUTHEAST OF THE CWA TONIGHT AND FRIDAY...AND ACROSS MUCH OF
THE FORECAST AREA SUNDAY AND SUNDAY NIGHT. A PUSH OF EVEN COLDER
ARCTIC AIR APPEARS POSSIBLE EARLY NEXT WEEK IN THE WAKE OF THE
WEEKEND SYSTEM...LIKELY ENHANCED BY FRESH SNOW COVER.
STRONG LOW PRESSURE WAS OVER EASTERN LAKE SUPERIOR EARLY THIS
MORNING...WITH ITS TRAILING COLD FRONT WELL EAST OF THE FORECAST
AREA FROM LOWER MICHIGAN TO THE LOWER OHIO VALLEY AND ARKLATEX.
COLDER/DRIER ARCTIC AIR WAS STEADILY SPREADING INTO THE MIDWEST WITH
TEMPS IN THE TEENS/LOWER 20S AND DEW POINTS IN THE SINGLE DIGITS AND
TEENS. COLD ADVECTION WILL LIKELY OFFSET ANY DIURNAL WARMING TODAY
WITH TEMPS EXPECTED TO DIP A LITTLE MORE THIS MORNING THEN BECOME
STEADY. THOUGH APPROACHING AIR MASS IS DRIER...THERE IS CONSIDERABLE
LOW CLOUDINESS WITHIN COLD ADVECTION AND EVEN A NARROW BAND OF
FLURRIES OR LIGHT SNOW ACROSS FAR EASTERN IOWA AND NORTHWEST
ILLINOIS AT THIS HOUR. THIS APPEARS TO BE DRIVEN BY SHORT WAVE
ENERGY AND A TIGHTENING IN THE THERMAL GRADIENT AROUND NEAR 800
MB...WHICH THE RAP DEPICTS NICELY WITH AN AREA OF FRONTOGENESIS
CLOSELY TIED TO CURRENT RADAR RETURNS. THE RAP CONTINUES TO SPREAD
THIS FORCING INTO NORTH CENTRAL AND FAR NORTHERN IL EARLY THIS
MORNING BEFORE RAPIDLY WEAKENING IT PRIOR TO MIDDAY. LOW LEVEL CLOUD
COVER WILL LIKELY ERODE BY THIS AFTERNOON...THOUGH PRESENCE OF
STRONG SOUTHWESTERLY JET ALOFT AND ADDITIONAL MINOR AMPLITUDE
MID-LEVEL WAVES WILL LIKELY KEEP SOME DEGREE OF MID/HIGH CLOUDS
AROUND THROUGH THE DAY. FARTHER TO THE SOUTHEAST...SERIES OF FAST
MOVING MID-LEVEL DISTURBANCES WILL HELP TIGHTEN LOW LEVEL BAROCLINIC
ZONE ACROSS THE OHIO VALLEY...FRONT FRONTOGENETIC BANDING DEVELOPING
SNOW FROM SOUTHERN MISSOURI INTO OHIO. MODEL GUIDANCE CONTINUES TO
FOCUS AXIS OF ACCUMULATING SNOWFALL SOUTHEAST OF THE CWA LATER TODAY
INTO FRIDAY...WITH FARTHEST NORTH SOLUTIONS CLIPPING SOUTHEAST TIER
OF WFO LOT CWA COUNTIES WITH AT BEST A MINOR ACCUMULATION OF LESS
THAN A HALF INCH WITH DISTURBANCES THIS EVENING AND AGAIN FRIDAY
MIDDAY/AFTERNOON.
LITTLE CHANGE IN THINKING WITH RESPECT TO TEMPERATURES TODAY THROUGH
SATURDAY...WITH PERSISTENT INTRUSION OF ARCTIC AIR INTO FRIDAY AND
SATURDAY AS SURFACE HIGH PRESSURE EVENTUALLY BUILDS INTO THE REGION.
GUIDANCE REMAINS IN DECENT AGREEMENT WITH THE GENERAL TREND OF
20S/LOW 30S TODAY...THEN HIGHS IN THE UPPER TEENS TO LOW 20S FRI/SAT
WITH LOWS RANGING FROM THE SINGLE DIGITS NORTHWEST TO THE TEENS
SOUTHEAST.
ENERGY NOTED IN WATER VAPOR IMAGERY CURRENTLY DIGGING SOUTH INTO
BRITISH COLUMBIA IS PROGGED TO AMPLIFY OVER THE WEST COAST OVER THE
NEXT COUPLE OF DAYS...THEN MOVE EAST ACROSS THE ROCKIES AND PLAINS
SUNDAY AND ACROSS THE GREAT LAKES REGION SUNDAY NIGHT. WHILE SOME
MINOR DETAIL DIFFERENCES REMAIN IN THE LONGER RANGE MODEL
GUIDANCE...THERE IS DECENT CONSENSUS IN A BROAD SURFACE LOW
DEVELOPING ACROSS THE REGION AND LIFTING NORTHEAST ACROSS THE GREAT
LAKES SUNDAY NIGHT AND EARLY MONDAY. DRY EASTERLY FLOW IN MODIFIED
ARCTIC AIR WILL LIKELY BE A BIT SLOW TO SATURATE AS WARM/MOIST
ADVECTION DEVELOPS IN ADVANCE OF THIS SYSTEM SUNDAY...THOUGH LIGHT
SNOW IS EXPECTED TO DEVELOP FROM THE WEST/SOUTHWEST THROUGH THE
AFTERNOON. SNOW IS THEN EXPECTED SUNDAY NIGHT INTO EARLY MONDAY
MORNING...WITH CURRENT MODEL QPF SUGGESTING PERHAPS 2-3 INCHES
ACROSS ESPECIALLY THE CENTRAL AND NORTHWEST PARTS OF THE FORECAST
AREA BEFORE TAPERING TO FLURRIES MONDAY MORNING. IF THIS SNOW COVER
DOES MATERIALIZE...ANOTHER BRIEF SHOT OF ARCTIC AIR WOULD LIKELY
PRODUCE COLDER TEMPS EARLY/MID NEXT WEEK. COLDEST PERHAPS WOULD BE
TUESDAY MORNING...WHEN WEAK RIDGE AXIS WOULD SUPPORT BEST
RADIATIONAL COOLING.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* MVFR CIGS WITH A SMALL POSSIBILITY OF IFR.
* GUSTY WEST WINDS VERY GRADUALLY TURNING NORTHWEST.
LENNING
//DISCUSSION...UPDATED 06Z...
A STRONG LOW PRESSURE CENTER CROSSING LAKE SUPERIOR AND MOVING
INTO ONTARIO OVERNIGHT HAS DRAGGED A COLD FRONT ACROSS THE LOCAL
TERMINALS. GUSTY WEST WINDS BEHIND THE FRONT WILL PERSIST TONIGHT
AND MOST OF THURSDAY BEFORE DIMINISHING AND SLOWLY TURNING
NORTHWEST BY EVENING. MVFR CEILINGS ALSO HAVE SPREAD ACROSS THE
AREA BUT SHOULD BEGIN TO BREAK UP DURING THE MORNING AS DRIER AIR
MOVES IN WITH THE APPROACHING HIGH PRESSURE BEHIND THE FRONT.
POCKETS OF IFR ALSO ARE SHOWING UP IN THE LATEST OBSERVATIONS...SO
PERIODS OF 600-800 FT CIGS ALSO ARE POSSIBLE OVERNIGHT.
LENNING
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN WIND TRENDS.
* MEDIUM TO HIGH CONFIDENCE OF MVFR PERSISTING INTO THE MORNING
AND MEDIUM CONFIDENCE THAT IFR WILL NOT DEVELOP.
LENNING
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW...WITH SNOW LIKELY SUNDAY NIGHT. IFR CONDITIONS.
MONDAY...SLT CHC SNOW EARLY.
TUESDAY...PRIMARILY VFR.
KJB
&&
.MARINE...
321 AM CST
LOW PRESSURE CROSSING LAKE SUPERIOR INTO ONTARIO THIS MORNING
DRAGGED A COLD FRONT ACROSS THE LAKE LAST EVENING. WINDS TURNED
SOUTHWEST BEHIND THE FRONT BUT ARE VEERING TO WEST THIS MORNING
AND WILL CONTINUE VEERING TO NORTHWEST TONIGHT. IN THE TIGHTER
PRESSURE GRADIENT ACROSS THE NORTHERN HALF OF THE LAKE CLOSER TO
THE LOW...GALES TO 40 KTS WITH POSSIBLY HIGHER GUSTS ARE EXPECTED
TO PERSIST INTO THIS EVENING. THE SOUTHERN HALF OF THE LAKE ALSO
WILL BE WINDY...BUT GALE FORCE GUSTS ARE EXPECTED TO BE
CONSIDERABLY LESS FREQUENT ACROSS THE SOUTH HALF. LATEST 3 AM CST
SHIP OBS IN THE FAR SOUTHERN PART OF THE LAKE HAD WIND SPEEDS
ONLY IN THE TEENS...WHILE SHIP OBS IN THE NORTHERN LAKE HAD WINDS
IN THE MID 30 KNOT RANGE.
DEBATED WHETHER TO TRIM THE END OF THE SMALL CRAFT ADVISORY FOR
THE INDIANA NEARSHORE WATERS AS THE PRESSURE GRADIENT FALLS OFF
QUICKLY THIS EVENING. DECIDED WITH SUCH COLD AIR AND A NORTHWEST
FETCH...WAVES SHOULD BE EASY TO MAINTAIN...AND GUSTS INTO THE MID
20 KNOT RANGE MAY WELL PERSIST INTO THE OVERNIGHT HOURS.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868 UNTIL 9 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 3 PM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM FRIDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
229 AM CST Thu Dec 5 2013
...Updated for the long term discussion...
.SYNOPSIS...
ISSUED AT 1102 AM CST WED DEC 4 2013
At 12z Wednesday a 300mb jet extended from southern California
into far western Nebraska. A -35c to -37c 500mb low was located
over southeastern Idaho with an upper level trough extending
southwest of this upper low into southern California. Ahead of
this upper level trough 80 to 90meter 12hour height rises were
observed near the four corners region which was where the left
exit region of a 300mb +100kt jet was positioned. A 700mb
baroclinic zone stretched from the four corners region across
western Kansas and into southeastern Nebraska with an area of
higher dewpoints observed along this baroclinic zone. The 850mb
temperatures at 12z Wednesday across the central plains varied
from -3c at Amarillo to -9c at Dodge city to -16c at North Platte.
This a 18c to 25c drop when comparing the 850mb temperatures from 12z
Wednesday to 12z Tuesday. Dodge City and North Platte soundings
from 12z also indicated a fairly deep layer of moisture which
extended from near the surface to at least the 800mb level.
&&
.SHORT TERM...(This evening through Thursday)
ISSUED AT 147 PM CST WED DEC 4 2013
19z visible satellite loop indicating some clearing skies across
western Kansas as the low clouds gradually erode. Further west mid
level cloud cover/moisture was on the increase and this appears to
be related to a 700mb baroclinic zone that extended from northeast
Colorado into Nebraska. Tonight 700mb frontogenesis will be
improving along this mid level baroclinic zone as the right
entrance region of a 300mb jet crosses western Kansas. Based on
the NAM and RAP at 18z Wednesday this 700mb baroclinic zone should
be located across northeast Colorado 18z and based on the latest
composite mosaic radar loop these models appear to have a decent
handle on this. As a result will follow the 700mb baroclinic zone
from NAM and RAP overnight and place the better chances for
measurable snow along this boundary given the improving
frontogenesis and the location of the right entrance region of an
upper level jet as it crosses the central plains during the
overnight hours.
Initial thoughts for snow amounts tonight...a brief period of
steady light to even moderate snow may accompany the jet steak
which may result in a quick inch of snow across portions of west
central and north central Kansas. Have therefore place snow
accumulations of 1 to around 1.5 inches in this this area between
00z Thursday and 12z Thursday. Further south some light
snow/flurries will still be possible, however given the loss of
the upper level dynamics lower snow amounts are anticipated.
On Thursday the better mid level forcing will be located near the
Oklahoma border through much of the day as a southern branch upper
level disturbance approaches southwest Kansas from New Mexico.
Another brief period of steady light to moderate snow will be be
possible during the day across far southwest Kansas and near the
Oklahoma border. Once again 1 to 2 inches of snowfall will be
possible with this steadier snow and lower snow amounts further
north. At this time snow totals over the next 24 to 36 hours are
expected to be mainly between 1 to 2 inches so inserted these snow
totals into the hazardous weather outlook but will not issue a
winter weather advisory at this time.
Wind chill values towards daybreak will fall back mainly into the
5 to 10 degrees below zero range with wind chill readings
approaching -15c in a few locations of west central Kansas. On
Thursday as afternoon temperatures struggle to reach the 15 to
near 20 degree range the wind chill values are expected to be
mainly in the single digits.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 227 AM CST THU DEC 5 2013
Friday night will see the strong arctic high pressure system shift
slightly to the east, with a southerly flow returning at the surface
in our western zones near the Colorado border. A trough of low
pressure will form in eastern Colorado Friday afternoon, and migrate
into far western Kansas overnight Friday night. On Saturday, a mid
level wave of low pressure will cross from the Rockies into the
Plains, and may bring a little snow to far western Kansas by noon
time, near the trough. The mid level lift and instability will move
across the rest of southwestern Kansas and spread light snow into
central Kansas Saturday afternoon. The large upper level trough at
H5 will slowly move eastward into plains Saturday night, and send
small waves of energy through the plains. This will support light
snow through Sunday, with a slight chance of snow in our east, east
of a Hays to Coldwater line, Sunday night. This snow event looks
very weak, and an inch or less of new snow is anticipated. After
Sunday night, the upper and lower support for snow will shift east
and we should see a slight warm up.
Friday night looks really cold with the arctic air extending well
south of us into Oklahoma. In addition, skies will be mostly clear
for much of the night, allowing temps to dive quickly after
sundown. For these reasons, some of our zones from Syracuse to
Dighton to Wakeeney may bottom out to the -2F degree range. light
easterly winds at 7 to 8 knots will still produce wind chill
readings in the advisory level, down in the -15F to -19F range. A
wind chill advisory may be needed for Friday night, but later shifts
can evaluate that. Saturday, Sunday and even Monday all look very
cold with maximum temperatures only in the teens and minimums in the
single digits. Tuesday will see a little warm up with south winds
returning. Highs Tuesday into Thursday will reach the 30s, while
low temperatures will be in the teens and 20s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 526 PM CST WED DEC 4 2013
VFR conditions will prevail tonight with northerly winds at 15 to
20 knots gusting to around 25 knots at times. There is a slight
chance of light snow towards sunrise and have placed a TEMPO group
to account for this. Northerly winds then decrease to around 10
knots tomorrow morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 17 7 16 2 / 60 70 0 0
GCK 18 7 14 2 / 40 50 0 0
EHA 14 7 15 3 / 80 80 0 0
LBL 16 9 16 2 / 80 80 0 0
HYS 19 7 15 1 / 10 20 0 0
P28 25 12 19 5 / 50 50 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Burke
AVIATION...Hovorka_42
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1151 PM MST WED DEC 4 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 223 PM MST WED DEC 4 2013
ARCTIC COLD HAS ENTERED THE CWA AND IS EXPECTED TO STICK AROUND FOR
A WHILE. SOME LIGHT SNOW FELL THIS MORNING...WITH HEAVIEST BANDS
OVER EASTERN COLORADO BRINGING NEARLY AN INCH IN A FEW SPOTS.
TONIGHT ANOTHER ROUND OF SNOWFALL IS EXPECTED WHICH COULD BRING A
QUICK INCH IN A FEW SPOTS...BUT OTHERWISE THE COLD WILL BE THE MAIN
HAZARD IN THE SHORT TERM.
TODAY...SUBSIDENCE ACROSS THE TRI-STATE LEAD TO SNOWFALL ENDING AND
EVEN SOME CLEARING SKIES...AND HIGHS WERE A CHALLENGE OF BALANCING
THE ADDITIONAL SOLAR RADIATION WITH COLD AIR ADVECTION. WINDS ARE A
BIT STRONGER THAN THE ORIGINAL FORECAST...BUT A BLEND OF 12Z MOS
GUIDANCE HANDLED THE STRONGER WINDS A LITTLE BETTER THAN MOST OF THE
OTHER GUIDANCE.
TONIGHT...MUCH OF EASTERN COLORADO AND PARTS OF NW KANSAS/SW
NEBRASKA WILL REACH LOWS NEAR OR BELOW ZERO...APPROACHING RECORD
COLD VALUES. A QUICK CHANCE FOR SNOWFALL DUE TO A NARROW BAND
ENHANCED FRONTOGENESIS AS SUGGESTED BY SHORT RANGE GUIDANCE. A FEW
SPOTS NEAR AND SOUTH OF I-70 COULD SEE UP TO AN INCH...BUT ANY
SNOWFALL THAT DOES FALL WILL BE QUICK TO EXIT. SNOWFALL AND CLOUD
COVER WILL LIMIT TEMPS IN THE EVENING HOURS...BUT ONCE THE SNOW
SHOWERS AND CLOUDS MOVE OUT TEMPERATURES WILL DROP RAPIDLY AS COLD
AIR PUSHES SOUTHWARD...850 TEMPS DROPPING TO NEAR -20 C...VERY COLD
EVEN BY WINTER STANDARDS. LOWS WILL BE NEAR TO BELOW
ZERO...APPROACHING RECORD VALUES FOR MANY LOCATIONS. COMBINED WITH
WINDS OF 20-25 MPH AM VERY CONFIDENT ADVISORY-LEVEL WIND CHILL
VALUES AS WIND CHILLS DROP TO -15 TO -25...ESPECIALLY IN EASTERN
COLORADO. IF SKIES CLEAR AS RAPID AS THE RUC IS INDICATING...EVEN
COLDER TEMPS/WIND CHILLS ARE POSSIBLE.
THURSDAY...COLD. HIGHS WILL STRUGGLE TO REACH THE TEENS...EVEN WITH
PARTIAL SUNSHINE. WINDS WILL BE LIGHT...WITH WIND CHILLS WILL BE
NEAR ZERO MUCH OF THE DAY.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 1142 PM MST WED DEC 4 2013
ARCTIC AIR MASS WILL REMAIN ENTRENCHED THROUGH MID WEEK...BUT
THERE ARE SIGNS THAT IT WILL FINALLY RELENT TOWARDS THE VERY END
OF THE PERIOD. MEANWHILE...LIGHT SNOW ASSOCIATED WITH THE MAIN
UPPER TROUGH AXIS WILL OCCUR ON SUNDAY AND WIND DOWN SUNDAY NIGHT.
SNOW AMOUNTS LOOK TO BE IN ADVISORY RANGE OF 1 TO 3 INCHES.
SURFACE RIDGE WILL NOSE IN SUNDAY NIGHT BEHIND THE SYSTEM. THE
FRESH SNOW PACK COMBINED WITH A SECONDARY SURGE OF COLD AIR
SUGGESTS TEMPERATURES ON SUNDAY NIGHT/MONDAY MORNING COULD TANK TO
NEAR 10 BELOW. THE REMAINDER OF THE PERIOD WILL BE DRY AS
NORTHWEST FLOW MONDAY AND TUESDAY TRANSITIONS TO ZONAL FLOW BY
WEDNESDAY AND THURSDAY. TEMPERATURES WILL GRADUALLY MODERATE AND
THURSDAY APPEARS TO BE THE NEXT BEST CHANCE OF GETTING ABOVE
FREEZING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1014 PM MST WED DEC 4 2013
CURRENT RADAR INDICATES BAND OF LIGHT SNOW MOVING OUT OF THE AREA
WITH METARS SHOWING A RETURN TO VFR CONDITIONS. EXPECT VFR TO
PREVAIL OVERNIGHT AT KGLD AND KMCK AS SURFACE HIGH PRESSURE BUILDS
INTO THE CENTRAL PLAINS. LATER THURSDAY AFTERNOON SOUNDINGS AT BOTH
SITES SHOW AN INCREASE IN MID LEVEL CLOUDS BUT NO PRECIPITATION IS
EXPECTED.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND CHILL ADVISORY UNTIL 11 AM MST /NOON CST/ THURSDAY FOR
KSZ001>003-013-014-027.
CO...WIND CHILL ADVISORY UNTIL 11 AM MST THURSDAY FOR COZ090>092.
NE...WIND CHILL ADVISORY UNTIL 11 AM MST /NOON CST/ THURSDAY FOR
NEZ079>081.
&&
$$
SHORT TERM...JJM
LONG TERM...024
AVIATION...FS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1016 PM MST WED DEC 4 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 223 PM MST WED DEC 4 2013
ARCTIC COLD HAS ENTERED THE CWA AND IS EXPECTED TO STICK AROUND FOR
A WHILE. SOME LIGHT SNOW FELL THIS MORNING...WITH HEAVIEST BANDS
OVER EASTERN COLORADO BRINGING NEARLY AN INCH IN A FEW SPOTS.
TONIGHT ANOTHER ROUND OF SNOWFALL IS EXPECTED WHICH COULD BRING A
QUICK INCH IN A FEW SPOTS...BUT OTHERWISE THE COLD WILL BE THE MAIN
HAZARD IN THE SHORT TERM.
TODAY...SUBSIDENCE ACROSS THE TRI-STATE LEAD TO SNOWFALL ENDING AND
EVEN SOME CLEARING SKIES...AND HIGHS WERE A CHALLENGE OF BALANCING
THE ADDITIONAL SOLAR RADIATION WITH COLD AIR ADVECTION. WINDS ARE A
BIT STRONGER THAN THE ORIGINAL FORECAST...BUT A BLEND OF 12Z MOS
GUIDANCE HANDLED THE STRONGER WINDS A LITTLE BETTER THAN MOST OF THE
OTHER GUIDANCE.
TONIGHT...MUCH OF EASTERN COLORADO AND PARTS OF NW KANSAS/SW
NEBRASKA WILL REACH LOWS NEAR OR BELOW ZERO...APPROACHING RECORD
COLD VALUES. A QUICK CHANCE FOR SNOWFALL DUE TO A NARROW BAND
ENHANCED FRONTOGENESIS AS SUGGESTED BY SHORT RANGE GUIDANCE. A FEW
SPOTS NEAR AND SOUTH OF I-70 COULD SEE UP TO AN INCH...BUT ANY
SNOWFALL THAT DOES FALL WILL BE QUICK TO EXIT. SNOWFALL AND CLOUD
COVER WILL LIMIT TEMPS IN THE EVENING HOURS...BUT ONCE THE SNOW
SHOWERS AND CLOUDS MOVE OUT TEMPERATURES WILL DROP RAPIDLY AS COLD
AIR PUSHES SOUTHWARD...850 TEMPS DROPPING TO NEAR -20 C...VERY COLD
EVEN BY WINTER STANDARDS. LOWS WILL BE NEAR TO BELOW
ZERO...APPROACHING RECORD VALUES FOR MANY LOCATIONS. COMBINED WITH
WINDS OF 20-25 MPH AM VERY CONFIDENT ADVISORY-LEVEL WIND CHILL
VALUES AS WIND CHILLS DROP TO -15 TO -25...ESPECIALLY IN EASTERN
COLORADO. IF SKIES CLEAR AS RAPID AS THE RUC IS INDICATING...EVEN
COLDER TEMPS/WIND CHILLS ARE POSSIBLE.
THURSDAY...COLD. HIGHS WILL STRUGGLE TO REACH THE TEENS...EVEN WITH
PARTIAL SUNSHINE. WINDS WILL BE LIGHT...WITH WIND CHILLS WILL BE
NEAR ZERO MUCH OF THE DAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 223 PM MST WED DEC 4 2013
THURSDAY NIGHT-FRIDAY NIGHT...H5 LONGWAVE TROUGH WILL REMAIN IN
PLACE WITH ARCTIC AIR MASS AT THE SURFACE. LOOKS LIKE THERE WILL BE
VERY LITTLE CHANGE IN TEMPS WITH HIGHS IN THE TEENS AND LOWS AROUND
ZERO. MY CURRENT LOW TEMP FORECAST IS A CONSERVATIVE BLEND...AND IF
SKIES CLEAR NEAR DAYBREAK FRIDAY MORNING WE COULD SEE RECORD LOWS IN
THE -5 TO -15F BELOW ZERO RANGE. EVEN WITH SLIGHTLY WARMER TEMPS WE
WILL PROBABLY NEED TO CONSIDER WIND CHILL ADVISORIES BOTH NIGHTS.
MODELS SHOW SOME WEAK ENERGY ROTATING THROUGH THE BASE ON THE LARGE
SCALE TROUGH. BEYOND INCREASING CLOUD COVER THE FORECAST SHOULD
REMAIN DRY DURING THESE PERIODS. I DECIDED AGAINST MENTION OF
FLURRIES...THOUGH I COULDNT RULE OUT A FEW FLURRIES DURING THE
DAYTIME PERIOD THURSDAY IF WE ARE ABLE TO GET SOME WEAK INSTABILITY.
SATURDAY-SUNDAY NIGHT...THE NEXT GOOD CHANCE FOR ACCUMULATING SNOW
LOOKS TO ARRIVE THIS WEEKEND WHEN A SHORTWAVE TROUGH ORIGINATING
OVER THE PACIFIC NW MOVES TO THE FOUR CORNERS REGION SATURDAY AND
ACROSS THE PLAINS AS A NEGATIVELY TILTED TROUGH SUNDAY. VERY GOOD
FORCING AHEAD OF THIS FEATURE AND DECENT MOISTURE ADVECTION SHOULD
COMBINE TO PRODUCE ACCUMULATING SNOW FOR A LARGE PORTION OF THE
PLAINS. MODELS GENERALLY SHOW SIMILAR TIMING ON THIS
FEATURE...HOWEVER THERE IS LESS CONTINUITY ON THE TRACK AND THIS
WILL HAVE A LARGE IMPACT ON SNOW TOTALS OVER OUR CWA. DURING THIS
FORECAST UPDATE I BUMPED POPS UP SOME ON SATURDAY NIGHT AND SUNDAY
TO HIGH CHANCE CATEGORY WITH INCREASING CONFIDENCE IN MEASURABLE
SNOW. BEST GUESS BASED ON A MEAN STORM TRACK PUTS SNOW AMOUNTS IN
THE 1-3" RANGE OVER OUR CWA WITH THE HIGHEST AMOUNTS ACROSS THE
SOUTHEAST WHERE BETTER FORCING ASSOCIATED WITH MID LEVEL
FRONTOGENETICAL BAND HAS A BETTER CHANCE OF SETTING UP.
MONDAY-WEDNESDAY...DRY FORECAST IS EXPECTED WITH UPPER LEVEL
CONFLUENCE AND H5 PATTERN BECOMING SLIGHTLY MORE ZONAL. MODELS DO
ADVERTISE A GRADUAL WARMING TREND WITH HIGHS FINALLY APPROACHING (OR
GOING ABOVE) FREEZING BY TUESDAY AND WEDNESDAY. NORTHERN JET STREAM
STILL APPEARS TO BE VERY ACTIVE HOWEVER SO ADDITIONAL REINFORCING
SHOTS OF COLD AIR COULD KEEP OUR TEMPERATURES BELOW NORMAL THROUGH
NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1014 PM MST WED DEC 4 2013
CURRENT RADAR INDICATES BAND OF LIGHT SNOW MOVING OUT OF THE AREA
WITH METARS SHOWING A RETURN TO VFR CONDITIONS. EXPECT VFR TO
PREVAIL OVERNIGHT AT KGLD AND KMCK AS SURFACE HIGH PRESSURE BUILDS
INTO THE CENTRAL PLAINS. LATER THURSDAY AFTERNOON SOUNDINGS AT BOTH
SITES SHOW AN INCREASE IN MID LEVEL CLOUDS BUT NO PRECIPITATION IS
EXPECTED.
&&
.CLIMATE...
ISSUED AT 223 PM MST WED DEC 4 2013
LOW TEMPERATURES WILL APPROACH RECORD VALUES TONIGHT.
CURRENT DAILY RECORD LOWS FOR THURSDAY (DEC 5)...
GOODLAND.....-8 (1972)
HILL CITY....-5 (1909)
BURLINGTON...-11 (1972)
MCCOOK.......-10 (1909)
YUMA.........-5
TRIBUNE......-2
COLBY........-8
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND CHILL ADVISORY UNTIL 11 AM MST /NOON CST/ THURSDAY FOR
KSZ001>003-013-014-027.
CO...WIND CHILL ADVISORY UNTIL 11 AM MST THURSDAY FOR COZ090>092.
NE...WIND CHILL ADVISORY UNTIL 11 AM MST /NOON CST/ THURSDAY FOR
NEZ079>081.
&&
$$
SHORT TERM...JJM
LONG TERM...DR
AVIATION...FS
CLIMATE...JJM
AREA FORECAST DISCUSSION...UPDATED
NWS PADUCAH KY
1152 PM CST Wed Dec 4 2013
.UPDATE...
ISSUED AT 1140 PM CST WED DEC 4 2013
Updated the aviation discussion for the 06Z TAF issuance.
UPDATE ISSUED AT 836 PM CST WED DEC 4 2013
Used the latest HRRR model to update wind and temperature fields
tonight as the front is just a tad faster but temperatures really
drop right behind the front. Otherwise forecast looks on track
with a few showers developing southwest of IND. This precipitation
should increase and spread southwest into our area later this
evening. New NAM is still a bit faster than other models with the
onset of freezing rain by about 3 hours but will not make any
changes at this point.
&&
.SHORT TERM...(This Evening through Friday Night)
ISSUED AT 334 PM CST WED DEC 4 2013
The 12Z models have sped up the arrival of the surface freezing
line, which is currently well past Kansas City and trucking this
way. The other trend is for a cooler overall solution, with many
areas quickly changing to sleet as the cold air arrives and then
quite a period of pure snow, especially across southern Illinois
and southeast Missouri.
Given that impacts now appear likely across southeast Missouri and
southern Illinois by late Thursday afternoon, will go ahead and
upgrade to a Winter Storm Warning at this time. Far northwest
areas will begin at 3 PM Thursday, and most of the area will begin
at 6 PM. The far southeast 4 counties of west Kentucky will not
start until Midnight Thursday Night, and some of that area may
not see problems until after daybreak. It will be a close call
down there for Friday morning.
Given the copious liquid equivalent precipitation forecast, there
will be the potential for 1/4 to 1/2 inch of icing, mainly over
west Kentucky and the Missouri Bootheel. Much of southeast
Missouri, southern Illinois and southwest Indiana will see mainly
sleet and snow with some locations receiving as much as a half a
foot before it is done. The precipitation should end as light snow
from west to east Friday afternoon and evening. An inch of snow
may still fall 00Z-03Z Saturday in the far southeast, so will
continue the Warning down there until 03Z.
In the meantime, it will be quite mild tonight ahead of the cold
front, and some scattered showers and maybe a thunderstorm or two
will be possible mainly over the bootheel and west Kentucky
overnight tonight.
.LONG TERM...(Saturday through Wednesday)
ISSUED AT 334 PM CST WED DEC 4 2013
Dry and chilly conditions are expected Saturday as high pressure
briefly settles over the northern U.S. As the high moves north, low
pressure will slide northeast from the western Gulf of Mexico,
skirting eastern portions of the PAH FA Sunday into Sunday night.
With cold air already in place, moisture pushed northward by this
weather system will be a wintry mix. ECMWF takes the low a bit
farther east than yesterday, and thus has backed off a bit on QPF.
GFS still shows significant moisture across our region late Saturday
night into Sunday. In either case, best moisture will be across
west Kentucky. Soundings continue to indicate a wintry mix, but
while yesterday`s run showed a majority freezing rain, today looks
more like an even mixture of freezing rain and sleet across west
Kentucky into southern portions of southeast Missouri. Farther
north and west, where temperatures will be colder and QPF will be
significantly lower, precipitation will be mainly light snow and
sleet.
Wintry precipitation is expected to transition to rain by Sunday
afternoon from the Pennyrile region west to the Land Between the
Lakes region in west Kentucky as temperatures climb a little above
freezing. This will help negate more significant ice accumulations.
Overall confidence is still not very high due to model
discrepancies, so kept snow and ice amounts fairly low for now.
Moisture is not as deep as our upcoming late work week system and is
moving more quickly, so amounts should not be as high as our first
system. However, if the late week system leaves us with snow/ice
coverage, this could have a big impact on our surface temps and lead
to more accumulation of whatever falls.
Precipitation will taper off from west to east Sunday night into
Monday, with just a small chance of light snow or sleet lingering in
our eastern counties on Monday. Any additional accumulations during
this time period will be light. Behind this weather system, the big
story will be bitterly cold temperatures. Monday highs will still
be in the upper 20s to middle 30s, which is 15 to 20 degrees below
seasonal normals. By Monday night, lows will be in the upper single
digits to middle teens, and then even a few degrees colder Tuesday
night, which would put us around 25 degrees below normal. Wind
chills around zero will be possible both Monday night and Tuesday
night across some of our northern counties.
&&
.AVIATION...
ISSUED AT 1140 PM CST WED DEC 4 2013
With the passage of a frontal system, cigs/vsbys will slowly
deteriorate from northwest to southeast through the valid period
with IFR cigs possible at KCGI/KPAH by the end of the period.
precipitation will likely begin as rain, then transition to
freezing rain, and eventually to ice pellets/sleet. Northwest winds
10-15 mph will gust up to 15-20 mph behind the frontal passage.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING from 6 PM Thursday to 6 PM CST Friday FOR
ILZ077-078-083-086-087-089>091-093-094.
WINTER STORM WARNING from 3 PM Thursday to 6 PM CST Friday FOR
ILZ075-076-080>082-084-085-088-092.
MO...WINTER STORM WARNING from 6 PM Thursday to 6 PM CST Friday FOR
MOZ112-114.
WINTER STORM WARNING from 3 PM Thursday to 6 PM CST Friday FOR
MOZ076-086-087-100-107>111.
IN...WINTER STORM WARNING from 6 PM Thursday to 6 PM CST Friday FOR
INZ081-082-085>088.
KY...WINTER STORM WARNING from 6 PM Thursday to 6 PM CST Friday FOR
KYZ001>008-010-011-013>016-018>020.
WINTER STORM WARNING from Midnight Thursday Night to 9 PM CST
Friday FOR KYZ009-012-017-021-022.
&&
$$
SHORT TERM...PS
AVIATION...JP
AREA FORECAST DISCUSSION
NWS GRAY ME
330 AM EST THU DEC 5 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL MOVE INTO NEW ENGLAND ON TODAY...
SPREADING SOME LIGHT PRECIPITATION INTO THE REGION. THE FRONT WILL
PUSH OFFSHORE TONIGHT. A WAVE OF LOW PRESSURE WILL TRACK
NORTHEAST ALONG THE FRONT ON FRIDAY AND MAY SPREAD RAIN OR SNOW
INTO SOUTHERN AREAS. HIGH PRESSURE PUSHES THE FRONT FURTHER SOUTH
ON SATURDAY WITH COLDER AIR MOVING IN. HIGH PRESSURE SHIFTS EAST
ON SUNDAY WITH LOW PRESSURE TRACKING UP THE EAST COAST ON MONDAY.
&&
.NEAR TERM /THROUGH TODAY/...
MODELS HAVE BACKED OFF ON THE TIMING OF ANY PRECIPITATION IN
ASSOCIATION WITH THE APPROACHING FRONT EARLY THIS MORNING WITH
EACH CONSECUTIVE RUN. HOWEVER...A WEAK AREA OF LOW PRESSURE OFF
THE NEW JERSEY COASTALINE IS BEGINNING TO GENERATE SOME LOW LEVEL
PRECIPITATION IN THE FORM OF LIGHT DRIZZLE AND LIGHT RAIN. WITH
TEMPERATURES IN THE LOWER TO MIDDLE 20S ACROSS THE REGION...EXPECT
SOME OF THIS MAY FREEZE ON CONTACT IF IT ARRIVES EARLY ENOUGH
PRIOR TO OUR EXPECTED DAYTIME WARMUP TODAY. WILL CONTINUE TO
MONITOR THIS VERY CLOSELY AS LATEST HRRR RUN BRINGS LIGHT MIXED
PRECIPITATION INTO FAR SOUTHERN AREAS SHORTLY AFTER 12Z.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
FROPA FINALLY OCCURS TONIGHT...CHANGING THE PRECIPITATION FROM A
STRATIFORM TO A SHOWERY TYPE OF WEATHER. TEMPERATURES IN THE
MOUNTAINS WILL BE COOLING OFF...SO THERE MAY BE SOME LIGHT
ACCUMULATIONS IN ANY PERSISTENT SNOW SHOWERS OVER THE HIGH
TERRAIN. USED A BLEND OF MAV/MET MOS WHICH BRINGS TEMPERATURES IN
THE MOUNTAINS TO BELOW FREEZING BY FRIDAY MORNING.
MODELS ARE IN DISAGREEMENT BY LATE IN THE DAY ON FRIDAY AS TO
WHETHER A WAVE OF LOW PRESSURE WILL RIDE UP THE FRONT AND SOUTH OF
NEW ENGLAND OR NOT. CURRENTLY...THE NAM IS MOST AGRESSIVE WITH THE
NORTHERN PROXIMITY OF PRECIPITATION...WHICH LEADS US TO THE LONG
RANGE PORTION OF THE FORECAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
FRI NIGHT A WEAK WAVE OF LOW PRES WILL MOVE E ALONG A STALLED
FRONT LOCATED S OF NEW ENGL. SRN AREAS OF ME/NH WILL BE ON THE NRN
FRINGE OF THE PCPN SHIELD SO SOME LGT PCPN IS EXPECTED. THE PCPN
SHOULD PRODUCE PSBLY A FEW INCHES OF SNOW OVER SRN AREAS AS ANY
MIXED PCPN GRDLY CHANGES TO SNOW AS CAA OCCURS FRI NIGHT. BY SAT
MRNG SKIES CLEAR AS HIGH PRES BUILDS ACROSS THE REGION. HIGH PRES
BECOMES CENTERED OVER THE REGION SUN ALLOWING ANOTHER NICE DAY.
SUN NIGHT THE SFC/UPR RDG AXIS OVR NEW ENGL MOVES EWD ALLOWING A
MOIST SWLY FLOW TO DEVELOP AS A BROAD WAA PATTERN DEVELOPS AND
MOVES EWD INTO THE REGION BY MON MORNING. MODELS IN GENERAL
AGREEMENT THAT CONDS WILL BE COLD ENOUGH FOR SNOW AND SOME ACCUMS
EXPECTED AT THE ONSET MON MRNG BEFORE CHANGING OVER TO A MIX AND
THEN RAIN FROM S-N DURING THE DAY. BY MON NIGHT SYSTEM RAPIDLY
EXITS AND CLEARING EXPECTED AS A STRONG COLD FRONT MOVES THROUGH
THE REGION LATE IN THE SYSTEMS WAKE. TUES AND WED MUCH COLDER
TEMPS EXPECTED WITH BELOW NORMAL TEMPS EXPECTED.
ACCEPTED TIMING AND POPS OF SUPERBLEND GUID FOR DAYS 4-7.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
SHORT TERM...CONDITIONS GRADUALLY DETERIORATE THIS MORNING WITH LOW
CLOUDS AND POSSIBLY FOG/DRIZZLE MOVE IN. THIS COULD LEAD TO AN
EXTENDED PERIOD OF IFR OR LIFR CONDITIONS THROUGH TONIGHT...BEFORE
SLOWLY IMPROVING TO MVFR CONDITIONS ON FRIDAY.
LONG TERM...
FRI NIGHT IFR CONDS IN SNW OR MIXED PCPN OVER SRN AREAS WHILE NRN
AND CNTRL AREAS MAILY VFR. ON SAT CONDS BECOME VFR ACROSS ALL
AREAS AND CONTINUE THRU SUNDAY. THE NEXT SYSTEM APPROACHES SUN
NIGHT AND MON LOWERING CONDS TO IFR/LIFR ACROSS ALL AREAS.
&&
.MARINE...
SHORT TERM...SOUTHERLY FLOW TODAY WILL GRADUALLY BUILD 3 TO 5 FOOT
WAVES WITH TIME. WILL ISSUES SCA FOR SEAS...WHICH WILL CARRY ON
INTO FRIDAY. THIS IS FOR THE OUTER WATERS ONLY.
LONG TERM...
NO FLAGS FRI NIGHT AND SAT. NW WINDS MAY APPROACH SCA CONDS SUN.
ON MON AN INCRG E FLOW WILL PRODUCE SCA CONDS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 PM THIS
AFTERNOON TO 4 PM EST FRIDAY FOR ANZ150-152-154.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
1246 AM EST THU DEC 5 2013
.SYNOPSIS...
HIGH PRESSURE SHIFTS EAST TONIGHT. A FRONTAL BOUNDARY WILL MOVE
INTO NEW ENGLAND ON THURSDAY... SPREADING SOME LIGHT PRECIPITATION
INTO THE REGION. THE FRONT WILL PUSH OFFSHORE THURSDAY NIGHT. A
WAVE OF LOW PRESSURE WILL TRACK NORTHEAST ALONG THE FRONT ON
FRIDAY AND MAY SPREAD RAIN OR SNOW INTO SOUTHERN AREAS. HIGH
PRESSURE PUSHES THE FRONT FURTHER SOUTH ON SATURDAY WITH COLDER
AIR MOVING IN. HIGH PRESSURE SHIFTS EAST ON SUNDAY WITH LOW
PRESSURE TRACKING UP THE EAST COAST ON MONDAY.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATE...
HAVE UPDATED GRIDS BASED ON CURRENT CONDITIONS ACROSS MAINE AND
NEW HAMPSHIRE. TEMPERATURES WILL LIKELY HOLD STEADY IN THE MID 20S
AS CLOUDS BEGIN TO FILTER IN ACROSS THE REGION. DRY AIR CONTINUES
IN THE LOWER LEVELS ACROSS OUR REGION AND PRECIPITATION CONTINUES
TO BE DELAYED UNTIL THURSDAY. PTYPE MAY BE AN ISSUE DURING THE MID
TO LATE MORNING HOURS. LATEST HRRR RUN CONTINUES TO SHOW SOME
LIGHT PRECIPITATION COMING IN OFF THE BRINK AROUND 13Z.
PREV DISC...
HIGH PRESSURE SHIFTS EAST TONIGHT WITH A RETURN SOUTHERLY
FLOW SETTING UP. SKY STARTS OFF INITIALLY MOSTLY CLEAR ACROSS THE
AREA... ALLOWING TEMPERATURES TO FALL. HOWEVER AS THE NIGHT GOES
ON... WARMER AIR WILL BE PUSHING NORTH ESPECIALLY JUST ABOVE THE
SURFACE. WILL LIKELY SEE CLOUDS MOVE IN THROUGH THE NIGHT AND
TEMPERATURES MAY WARM A FEW DEGREES BY MORNING. COULD SEE SOME FOG
AND DRIZZLE DEVELOP BY MORNING AS WELL. THE MORE SIGNIFICANT
PRECIPITATION NOW LOOKS TO BE DELAYED UNTIL THURSDAY AFTER
SUNRISE... WHICH LIMITS THE CHANCE OF FREEZING RAIN. HOWEVER... IF
PRECIPITATION DOES BEGIN EARLIER OR DRIZZLE SETS UP LATE TONIGHT
THEN THERE IS A CHANCE FOR SOME LIGHT ICING. CONFIDENCE IN
FREEZING PRECIPITATION IS NOT HIGH ENOUGH FOR AN ADVISORY AT THIS
TIME... BUT A SPECIAL WEATHER STATEMENT OR LAST MINUTE ADVISORY
COULD BE ISSUED ONCE THE TIMING OF PRECIPITATION AND ACCURACY OF
SURFACE TEMPERATURES IS BETTER KNOWN.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
PRECIPITATION BECOMES MORE WIDESPREAD DURING THE DAY THURSDAY...
THOUGH IT WILL STILL BE QUITE LIGHT. THE ONSHORE FLOW MAY LEAD TO
MORE OF A HEAVY FOG/DRIZZLE SITUATION. TEMPERATURES WILL BE
WARMING AS WARM AIR CONTINUES TO PUSH INTO THE AREA. PRECIPITATION
MAY START OUT AS FREEZING RAIN OR FREEZING DRIZZLE IN SOME AREAS
THOUGH CONFIDENCE IS NOT HIGH ENOUGH FOR AN ADVISORY AT THIS TIME.
TEMPERATURES WARM INTO THE 40S FOR JUST ABOUT ALL AREAS.
TEMPERATURES DO NOT FALL MUCH THURSDAY NIGHT AS CLOUDS AND
PRECIPITATION HANG AROUND. EXPECT LOWS IN THE 30S AND 40S. A FRONT
PUSHES SOUTH INTO THE AREA LATE IN THE NIGHT. AS THE FRONT PUSHES
SOUTH ON FRIDAY... TEMPERATURES BEGIN TO GET COOLER... ESPECIALLY
ALOFT. THIS MAY ALLOW PRECIPITATION TO TRANSITION TO SNOW BEFORE
ENDING. DO NOT EXPECT SIGNIFICANT ACCUMULATIONS. THIS
PRECIPITATION IS BEING DRIVEN BY A WEAK WAVE OF LOW PRESSURE
MOVING ALONG THE FRONT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
AS WE MOVE INTO THE WEEKEND THE FORECAST CONFIDENCE RAPIDLY
DECLINES. MOST GUIDANCE SUGGESTS THAT THURSDAYS FRONTAL BOUNDARY
SHOULD MOVE TO THE EAST OVER THE COASTAL WATERS BY 00Z SATURDAY...
LEAVING JUST A FEW SHOWERS AND FLURRIES ALONG THE COAST. HOWEVER
AN INITIALIZATION WITH AN ABNORMALLY STRONG TROUGH OVER THE WESTERN
UNITED STATES AND A WEAK HIGH OVER LOW BLOCK IN THE NORTH ATLANTIC
LEADS ME TO THINK THAT THE TROUGH MAY REMAIN STALLED OVER OUR AREA
INTO THE START OF THE WEEKEND. REGARDLESS OF WHERE THE FRONT
STALLS... EITHER OFFSHORE OR NEARSHORE... A WEAK WAVE DEVELOPING
NEAR THE DELMARVA PENINSULA WILL PROGRESS ALONG THE BOUNDARY
BRINGING FURTHER SHOWERS TO NORTHERN NEW ENGLAND THROUGH THE DAY
ON SATURDAY. TEMPERATURES ARE COLD ENOUGH TO KEEP IT ALL SNOW IN
THE INTERIOR... WITH 1 TO 2 INCHES POSSIBLE OVERNIGHT...WHILE THE
COAST WILL SEE RAIN SHOWERS MID DAY SATURDAY.
SUNDAY WILL BE QUIET AS A BRIEF PERIOD OF HIGH PRESSURE MOVES
OVER THE REGION. FOR THE START OF NEXT WEEK A BROAD UPPER LEVEL
TROUGH SHIFTS EASTWARD ALLOWING A LOW PRESSURE SYSTEM TO DEVELOP
OVER THE SOUTHEASTERN UNITED STATES... AND MOVE THROUGH NEW
ENGLAND ON MONDAY. A CLOUDY DAY WITH SOME SORT OF PRECIPITATION IS
A SAFE BET BUT THERE IS PLENTY OF TIME FOR CHANGES IN THIS STORM.
NOTABLE THERE ARE HINTS OF A DEVELOPMENT OF A COASTAL LOW TRACKING
THROUGH THE GULF OF MAINE WHILE THE MAIN LOW MOVES FURTHER INLAND
UP THE ST. LAWRENCE. THIS SECONDARY/MESO LOW COULD SERVE TO
ENHANCE PRECIPITATION ALONG THE COAST.... OR COULD BECOME THE MAIN
LOW CENTER IF THE LARGE SCALE TROUGH MOVE FURTHER EAST. FOR THE
MOUNTAINS THIS SHOULD BE A CLEAR CUT SNOW EVENT. AS USUAL THE
COAST IS CONSIDERABLY MORE DICEY WITH THE PRECIP TYPE STILL UP FOR
GRABS. HAVE OPTED FOR A BASIC RAIN/SNOW MIX AT THIS POINT AS IT IS
STILL TOO FAR OUT TO MAKE A CLEAR CALL BUT UNDOUBTEDLY PERIODS OF
SLEET AND FREEZING RAIN ARE POSSIBLE TOO.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
SHORT TERM...VFR CONTINUES THROUGH TONIGHT BUT CONDITIONS
DETERIORATE THURSDAY MORNING WITH LOW CLOUDS AND POSSIBLY
FOG/DRIZZLE MOVE IN. THIS COULD LEAD TO AN EXTENDED PERIOD OF IFR
OR LIFR CONDITIONS.
LONG TERM...
EXPECT MVFR TO IFR CONDITIONS THROUGH FRIDAY. CONDITIONS IMPROVE TO VFR
LATE SATURDAY AS HIGH PRESSURE BUILDS INTO THE REGION. ANOTHER
STORM WILL RETURN CONDITIONS TO IFR FOR MONDAY.
&&
.MARINE...
SHORT TERM...
CONDITIONS CONTINUE TO GET QUIETER OVER THE WATERS TONIGHT. BUT A
RETURN SOUTHERLY FLOW GETS STRONGER ON THURSDAY. COULD SEE GUSTS
TO 25 KT BEGINNING LATE THURSDAY INTO THURSDAY NIGHT.
LONG TERM...
QUIET WATERS THROUGH THE START OF THE PERIOD. GALES MAY BE NEEDED
LATE SUNDAY INTO MONDAY AHEAD OF THE DEVELOPING LOW.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 PM THIS
AFTERNOON TO 5 AM EST FRIDAY FOR ANZ150-152-154.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
505 AM EST THU DEC 5 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 504 AM EST THU DEC 5 2013
CONTINUED THE LAKE EFFECT SNOW ADVISORY FOR THE KEWEENAW WHICH WAS
EXTENDED THROUGH SUNDAY MORNING.
RADAR AND SURFACE OBSERVATIONS THIS MORNING ARE ONLY SHOWING A FEW
LINGERING SNOW SHOWERS OVER CENTRAL PORTIONS OF THE UPPER PENINSULA
WITH WINDS BEGINNING TO GUST OUT OF THE SOUTHWEST TO NEARLY 30MPH.
ALSO A WIDE RANGE OF TEMPERATURES ARE BEING DISPLAYED ACROSS THE CWA
WITH IWD AROUND 19F WILE NEWBERRY IS AROUND 36F. THE COOL DOWN IS
EXPECTED TO CONTINUE THROUGH THE DAY.
TODAY AND TONIGHT....LOW PRESSURE CENTERED OVER UPPER MICHIGAN AND
LAKE SUPERIOR EARLY THIS MORNING...WHILE A COLD FRONT WHILE A COLD
FRONT STRETCHES SOUTH AND WESTWARD FROM NORTH CENTRAL WI TO
SOUTHEAST MN AS OF 06Z. THE LOW IS EXPECTED TO CONTINUE
NORTHEASTWARD...PUSHING INTO ONTARIO BY DAY BREAK TODAY. AS THIS
HAPPENS THE COLD FRONT WILL HAVE PASSED THROUGH ALLOWING
TEMPERATURES TO DROP SIGNIFICANTLY ACROSS THE CWA. THIS WILL ALLOW
ANY LIQUID REMAINING ON THE ROADWAYS TO REFREEZE ALLOWING TRAVEL TO
CONTINUE TO BE SLIPPERY ONCE AGAIN...THEREFORE...HAVE ISSUED A SPS
TO DRAW ATTENTION TO THIS POTENTIAL HAZARD. THE POSITIVE SIDE OF
THIS FORECAST PERIOD IS THAT THE MIXED PRECIPITATION HAS MOVED OUT
OF THE AREA...LEAVING TEMPERATURES ALOFT COLD ENOUGH TO KEEP
PRECIPITATION IN THE FORM OF SNOW AS THE UPPER LEVEL TROUGH
ASSOCIATED WITH THE SURFACE LOW PUSHES OVERHEAD. FOR THE
DETAILS...WINDS WILL BECOME FAIRLY STRONG OUT OF THE WEST AS THE
SURFACE CONTINUES LIFTS NORTHEASTWARD FROM NORTHERN LAKE SUPERIOR AS
OF 12Z/05 TO NEAR JAMES BAY BY 18Z/05...WHERE IT WILL BECOME NEARLY
STATIONARY.
WITH THE COLD AIR ADVECTION ACROSS THE RELATIVELY WARM WATERS OF
LAKES SUPERIOR IN THE WAKE OF THE LOW...LAKE EFFECT SNOW WILL BECOME
A CONCERN...ESPECIALLY FOR WESTERLY WIND FAVORED SNOW BELTS OF THE
UPPER PENINSULA. AT 850MB THE COLDER TEMPERATURES REALLY START TO
BUILD INTO THE AREA BY 12Z/05 WITH MUCH OF THE WESTERN HALF OF THE
U.P. UNDER -10C TO -14C 850MB TEMPS. THIS WILL AGAIN BE FAVORABLE
FOR LAKE EFFECT SNOW DEVELOPMENT AS LAKE SURFACE TEMPERATURES ARE
CURRENTLY RUNNING AROUND 4C TO 5C. TEMPERATURE INVERSION HEIGHTS
AROUND 12Z ARE PROGGED TO BE AROUND 7KFT WITH MOISTURE AND LIFT
BEGINNING TO BE COLLOCATED IN THE FAVORED DGZ...MAINLY OVER THE
KEWEENAW PENINSULA. EVEN COLDER TEMPERATURES ARE EXPECTED TO PUSH IN
AT 850MB BY EARLY AFTERNOON AROUND 18Z WITH 850MB TEMPERATURES
RANGING FROM -14C OVER THE EAST TO -17 OVER THE WEST AND INVERSION
HEIGHTS LIFT TO AROUND 8KFT. THIS HELPS TO PLACE A GREATER DEAL OF
MOISTURE AN FORCING IN THE DGZ...ALLOWING FOR BETTER SNOW GROWTH
OVER THE KEWEENAW PENINSULA. REALLY NOT MANY CHANGES OCCUR FROM
18Z/05 THROUGH 06Z/06...EXCEPT FOR EVEN COLDER AIR PRESSES INTO THE
UPPER PENINSULA AT 850MB...WITH TEMPERATURES AT THAT LEVEL DROPPING
TO -20C OVER THE WESTERN U.P. SLIGHTLY DRYER AIR BUILDS IN ALOFT BY
06Z WHICH WILL LIKELY HELP TO REDUCE THE INTENSITY OF THE LAKE
EFFECT SNOW ACROSS THE KEWEENAW.
AWAY FROM THE KEWEENAW PENINSULA...THE MAIN ISSUE DURING THIS ENTIRE
TIME FRAME WILL BE MUCH COLDER TEMPERATURES BUILDING INTO THE
REGION. THE THICK CLOUD BANK THAT HAS LINGERED OVER MUCH OF THE AREA
OVER THE PAST COUPLE OF DAYS WILL TRY TO FINALLY BREAK UP...MAINLY
AWAY FROM LAKE SUPERIOR. THIS CLEARING ALONG WITH THE AFOREMENTIONED
COLDER 850MB TEMPERATURES WILL ALLOW OVERNIGHT LOWS TO DROP INTO THE
SINGLE DIGITS ABOVE ZERO OVER MUCH OF THE U.P. WITH THE INLAND WEST
AREAS POSSIBLY DROPPING INTO SINGLE DIGITS BELOW ZERO. THESE BELOW
ZERO TEMPERATURES COUPLED WITH WEST WINDS CLOSE TO 10 MPH OVERNIGHT
WILL MAKE WIND CHILL READINGS FALL TO 15 TO 20 BELOW ZERO. THIS
WOULD BE MARGINAL FOR A WIND CHILL ADVISORY...BUT THIS MAY BE NEEDED
BY THE AFTERNOON UPDATE.
ALSO...AWAY FROM THE KEWEENAW DECIDED TO ISSUE A GALE WARNING FOR
NORTHWESTERN LAKE MICHIGAN AS TIGHT PRESSURE GRADIENT BUILDS OVER
THE AREA ALONG WITH CAA ALLOWING STRONGER WINDS ALOFT TO MIX DOWN TO
THE RELATIVELY WARM SURFACE OF THE LAKE. RUC ANALYSIS SHOWS THE
POTENTIAL FOR 38KT WINDS TO MIX DOWN TO THE SURFACE OF THE LAKE.
ALREADY THIS MORNING THERE WERE A COUPLE OF OBS COMING IN WITH GUSTS
TO 32KTS...WITH THESE GUSTS LIKELY TO INTENSIFY THROUGH THIS
AFTERNOON.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 504 AM EST THU DEC 5 2013
MAIN FCST CONCERNS IN THE LONG TERM INCLUDE TEMPS/LES MAINLY IN THE
W-NW SN BELTS AND THE POTENTIAL FOR ANOTHER LARGER SCALE SN EVENT
EARLY NEXT WEEK. OVERALL TEMPS WL RUN WELL BLO NORMAL MOST OF THE
LONGER TERM WITH ARCTIC AIRMASSES DOMINATING.
FRI INTO SAT...AS THE LO TO THE NE DRIFTS SLOWLY INTO QUEBEC AND
ARCTIC HI PRES SLIDES FM WRN CANADA INTO THE NRN PLAINS...THE STEADY
FLOW OF VERY COLD AIR IS PROGGED TO GRDLY VEER TOWARD THE WNW AND
DIMINISH WITH TIME AS H85 TEMPS FALL SLOWLY TO ARND -17C OVER THE E
AND -21C OVER THE W BY 12Z SAT. THIS TYPICAL WINTER WX REGIME WL
FAVOR NEARLY CONTINUOUS LES IN THE FAVORED SN BELTS. A SHRTWV
TRACKING EWD THRU SRN ONTARIO/NRN LK SUP ON FRI NGT AND ACCOMPANYING
DEEPER MSTR MAY RESULT IN SOME ENHANCEMENT TO THE LES. ALTHOUGH THE
WINDS/BLSN WL BE DIMINISHING GRDLY...EXPECT LES/WINTER WX ADVYS TO
BE IN PLACE FOR THE FAVORED LES BELTS WITH FAVORABLE ALIGNMENT OF
THE LLVL OMEGA WITHIN THE DGZ. WENT HIER THAN MODEL CONSENSUS POPS
FOR LES IN THE FAVORED SN BELTS...USING CLIMATOLOGY GRIDS TO
EVALUATE THE POPS. AS THE LLVL WINDS DIMINISH...LAND BREEZE CNVGC
MAY PLAY A MORE IMPORTANT ROLE IN ENHANCING THE LES BANDS IN SOME
PLACES...WITH AT LEAST LOCALLY HEAVIER SN FALL APRCHG WARNING
CRITERIA. THIS POTENTIAL APPEARS GREATEST NEAR LK SUP E OF GRAND
MARAIS ON FRI NGT. SN/WATER RATIOS WL ALSO LIKELY BE MORE FVRBL FOR
LARGER FLAKES AS THE FLAKE FRACTURING DIMINISHES WITH THE WEAKENING
WINDS. AWAY FM THE FAVORED SN BELTS...THE WX DURING THIS TIME WL BE
VERY COLD BUT DRY. SUB ZERO MIN TEMPS WITH DAYTIME TEMPS STRUGGLING
TO RISE ABV 10F WL THE RULE OVER THE INTERIOR W HALF WITHIN THE LESS
MODIFIED ARCTIC AIR.
SAT NGT/SUN...THE SLOW EWD PUSH OF THE ARCTIC HI CENTER FM THE NRN
PLAINS THRU THE GREAT LKS/SLOWLY BACKING WINDS TO WSW ON SUN WL
CAUSE THE LES TO DIMINISH. THESE SHSN WL LINGER THE LONGEST OVER THE
KEWEENAW...AND EXTNENDED LES ADVY FOR THAT AREA UNTIL 12Z SUN.
DEPENDING ON HOW QUICKLY WAD CLDS SPILL INTO THE UPR LKS ON SUN TO
THE E OF A DEEPENING TROF IN THE PLAINS...TEMPS AT SOME PLACES OVER
THE INTERIOR ON EARLY SUN MRNG MAY FALL INTO THE TEENS BLO ZERO WITH
LGT WINDS UNDER THE ARRIVING SFC HI CENTER.
EXTENDED...NEXT LARGER SCALE PCPN EPISODE IS LIKELY TO ARRIVE ON SUN
NGT INTO EARLY MON. SOME OF THE LONGER TERM MODELS WERE SHOWING A
PHASING OF THE ARCTIC/POLAR BRANCHES WITH A DEEPER SFC LO TRACKING
THRU THE WCENTRAL GREAT LKS. IF THIS SCENARIO WERE TO VERIFY...A
WDSPRD ADVY SN WL BE PSBL OVER MUCH OF THE CWA. BUT THE MORE RECENT
LONGER TERM GUIDANCE APPEARS TO BE SHIFTING TOWARD LESS PHASING/A
WEAKER SFC LO THAT WOULD CAUSE JUST A FEW INCHES...MAINLY OVER THE E
CLOSER TO LO TRACK THRU LOWER MI. SINCE THE TREND HAS BEEN FOR A
WEAKER LO...GUIDANCE IS ALSO INDICATING THE AIRMASS FOLLOWING INTO
THE UPR LKS FOR LATER MON INTO TUE MAY NOT BE AS COLD AS PREVIOUSLY
INDICATED...WITH H85 TEMPS DOWN TO -25C INSTEAD OF -28C OR EVEN
-30C. STILL...LES WOULD BE A GOOD BET IN THE NW WIND SNOW BELTS. A
NUMBER OF THE LONGER TERM MODELS INDICATE A CLIPPER LO PRES MIGHT
TRACK THRU THE UPR LKS ON TUE AND BRING ANOTHER PERIOD OF MORE
WDSPRD -SN. THE CHILLY NW FLOW BTWN THE DEPARTING CLIPPER LO IN
ONTARIO AND HI PRES SINKING INTO THE CENTRAL CONUS WL THEN BRING
ANOTHER ROUND OF LES IN THE FAVORED SN BELTS. FINALLY...SOME OF THE
EXTENDED GUIDANCE IS HINTING THE UPR FLOW WL TREND MORE ZONAL LATER
NEXT WEEK AND BRING A MODERATION TO THE ARCTIC CHILL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1246 AM EST THU DEC 5 2013
LOW PRESSURE LIFTING NORTHEASTWARD OUT OF THE AREA WILL ALLOW SOME
LINGERING DRIZZLE THROUGH 08Z/05 KEEPING VSBY DOWN AT KSAW BEFORE A
COLD FRONT PUSHES INTO THE AREA. WINDS ARE EXPECTED TO BECOME
WESTERLY THROUGH THE OVERNIGHT HOURS WITH GUSTS INCREASING TO NEARLY
30 KNOTS AT TIMES. IWD AND CMX MAY ALSO HAVE SOME LINGERING DRIZZLE
BEFORE THE STRONGER...COLDER WINDS PUSH IN DROPPING CEILINGS DOWN AND
INCREASING THE POTENTIAL FOR LAKE EFFECT SNOW...ESPECIALLY DURING THE
DAY THURSDAY. THE PREVIOUSLY MENTIONED GUSTY WINDS MAY ALSO ACT TO
REDUCE VISIBILITY AT CMX AND IWD IF BLSN BECOMES AN ISSUE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 504 AM EST THU DEC 5 2013
EXPECT W GALES AS HI AS 40-45 KTS TO DEVELOP OVER LAKE SUPERIOR
TODAY AND CONTINUE INTO TONIGHT WITH SHARPENING PRES GRADIENT ON THE
SW FLANK OF LO PRES MOVING NE THRU ONTARIO. FREEZING SPRAY WILL ALSO
DEVELOP AS VERY COLD ARCTIC AIR SPILLS OUT OVER THE LAKE. THERE MAY
BE POCKETS OF HEAVY FREEZING SPRAY TONIGHT. THE W GALES WILL THEN
SLOWLY DIMINISH W-E LATE TONIGHT/FRI AS THE PRES GRADIENT SLOWLY
SLACKENS WITH THE SLOW APPROACH OF HI PRES FROM THE NORTHERN PLAINS.
WINDS WILL TURN TO THE S-SW ON SUN AND DIMINISH UNDER 15 KTS WITH
THE PASSAGE OF THE HI PRES TO THE E. A LO PRES SYSTEM MOVING NE THRU
LOWER MI ON SU NIGHT WILL FOLLOW THE DEPARTING HI. NW GALES AND MORE
FREEZING SPRAY WILL THEN DEVELOP ON MON AS ANOTHER ARCTIC AIRMASS
INVADES THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST SUNDAY FOR MIZ001-003.
LAKE SUPERIOR...
GALE WARNING UNTIL 11 AM EST FRIDAY FOR LSZ265>267.
GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ162.
GALE WARNING UNTIL 11 AM EST FRIDAY FOR LSZ264.
GALE WARNING UNTIL 4 AM EST FRIDAY FOR LSZ263.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ246>248-250-251.
GALE WARNING UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR
LSZ241>245.
LAKE MICHIGAN...
GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LMZ221-248-250.
&&
$$
SHORT TERM...KEC
LONG TERM...KC
AVIATION...KEC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1247 AM EST THU DEC 5 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 400 PM EST WED DEC 4 2013
20Z SFC CHART INDICATES ELONGATED SFC TROUGH FROM WCNTRL WI INTO
NORTHEAST IA WITH MSLP OF 998MB. WV AND RUC FCST SHOWS SHORTWAVE
PUSHING ACROSS SOUTHERN MINNESOTA. WAVE IS EXPECTED TO LIFT TOWARD
NORTHWEST WI WHILE DEEPENING OVERNIGHT. WARM AIR ADVECTION IN FULL
SWING AHEAD OF MAINLY 850MB LOW LIFTING INTO NW WISCONSIN. RUC13 AND
NAM12 HAVE DONE NICE JOB WITH THE WARM LAYER AT H9-H85 TODAY AND
BOTH SHOW H85 TEMPS OVER 2C REACHING NORTH OF ALL CWA BY 00Z.
SOUNDINGS OVER US CURRENTLY WOULD SUGGEST MAINLY FZRA BUT LINGERING
COLD POCKET NEAR SFC /TEMPS STILL IN MID-UPR 20S/ IS ALLOWING SLEET
TO HANG ON LONGER. CURRENTLY SNOW IS STILL FALLING OVER KEWEENAW
PENINSULA BUT IS EVEN STARTING TO MIX WITH FREEZING RAIN AND SLEET
OVER PORTIONS OF WESTERN UPR MICHIGAN. PLAN FOR EVENING IS THAT
MIXED FREEZING RAIN/SLEET/SNOW WILL CHANGE TO MAINLY FREEZING RAIN
AND SLEET WHILE MOSTLY FREEZING RAIN OR EVEN JUST RAIN OCCURS FOR
CNTRL CWA...ESPECIALLY CLOSER TO LK MICHIGAN SHORE. IF HEAVIER
PRECIP WAS EXPECTED OVR CNTRL THIS EVENING...ICING COULD BE BIGGER
ISSUE. RIGHT NOW...APPEARS THAT HEAVIER PRECIP IS GOING TO OCCUR IN
STRIPE FROM SOUTHERN MINNESOTA TOWARD WESTERN LK SUPERIOR IN AREAS
OF STRONGEST PVA/DIVERGENCE ALOFT JUST AHEAD OF TRACK OF SHORTWAVE.
GIVEN TREND TO MORE FZRA THOUGH...INCREASED ICE ACCUMS OVER INTERIOR
WEST AND CNTRL TO 0.10-0.20 INCHES THROUGH THE EVENING.
AS MID-LEVEL DRYING IN THE H7-H6 LAYER ARRIVES 03Z-06Z OVER THE
SOUTH AND AFTER 06Z IN THE NORTH...EXPECT WINTRY MIX OF PRECIP TO
TAPER OFF TO MORE OF A DRIZZLE/FREEZING DRIZZLE. ACTUALLY HEADLINES
SO FAR ARE WORKING OUT PRETTY WELL. DID HAVE TO GO WITH MORE SLEET
AND FREEZING RAIN AS WARM AIR WORKED IN QUICKER...BUT OVERALL IDEA
OF WINTRY MIX IS COVERED WITH GOING WINTER WEATHER ADVY. TIMING FOR
ENDING OF ADVY SEEMS GOOD AS WELL. ONLY POSSIBLE TROUBLE SPOTS WILL
IN THE INTERIOR CNTRL AND EAST THIS EVENING DUE TO ICING IF HEAVIER
PRECIP ENDS UP BLOSSOMING TO THE EAST OF PRIMARY SHORTWAVE. SOME
SHORT TERM HIGHER-RES MODELS INDICATE EXPANSION OF PRECIP OVER
SCNTRL THIS EVENING...BUT RADAR TRENDS UPSTREAM NOT REALLY SHOWING
THIS. IF SFC TEMPS STAY BLO FREEZING THAT AREA WILL NEED TO BE
WATCHED FOR POSSIBLE ADVY.
NOW ONTO LATE TONIGHT AND THURSDAY. MAIN ISSUE SEEMS TO BE LK EFFECT
AND BLOWING SNOW ON THE KEWEENAW. WEST WINDS MAY GUST OVER 40 MPH AT
TIMES LEADING TO THE BLSN/POOR VISIBILITY...PROBABLY 1/4-1/2SM AT
TIMES OVER PORTIONS OF THE KEWEENAW. LARGER SCALE FORCING BECOMES
NEGATIVE BUT THERE IS A LOT OF LINGERING MOISTURE BLO H8 WITH
COOLING AT INVERSION TOP TO -16C OR SO BY MIDDAY. GIVEN LK SUPERIOR
WATER TEMPS AROUND 3-4C THIS GIVES MORE THAN SUFFICIENT OVER-WATER
INSTABILITY FOR AT LEAST MODERATE LK EFFECT SNOW SHOWERS. WSW WINDS
OVER LAND WITH MORE OF A WESTERLY WIND OVER LK SUPERIOR INDICATES
STRONGER CONVERGENCE AREA SETS UP ACROSS KEWEENAW. SNOW AMOUNTS WILL
BE HELD DOWN SOME BY LOWER SLR/S AS THERE IS A LOT OF FRACTURING OF
SNOWFLAKES DUE TO THE STRONG WINDS. EXPECT ADVY LEVEL SNOWS OF 3-5"
OR 4-7" WITH A LOT OF WIND/BLSN. WILL ISSUE A SEPARATE LAKE EFFECT
SNOW ADVY FOR LATE TONIGHT THROUGH THURSDAY...GOING INTO PLACE RIGHT
WHEN THE CURRENT WINTER WEATHER ADVY FOR THE MESSY MIX OF SNOW/SLEET
AND FREEZING RAIN DIMINISHES.
AND FINALLY FOR LATE TONIGHT INTO THURSDAY...AWAY FM THE
KEWEENAW...MAIN ISSUE WILL BE COLD AIR PUSHING IN FM THE WEST.
ALREADY SEEING THIS ARCTIC AIR POURING ACROSS THE DAKOTAS THIS AFTN.
EXPECT SLOWLY FALLING TEMPERATURES THROUGH THE DAY AS THE COLD WORKS
EAST...WITH READINGS LIKELY INTO THE UPPER SINGLE DIGITS BY EVENING
OVER THE FAR WEST CWA. THIS COLDER AIR WILL ALSO FREEZE ANY
LINGERING SLUSH AND WATER IS ON THE ROADS AND SIDEWALKS...WHICH
COULD RESULT IN TOUGHER TRAVEL CONDITIONS IN SPOTS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 456 PM EST WED DEC 4 2013
THE EASY PART OF THIS FCST PERIOD WILL BE THE LACK OF MIXED
PRECIPITATION. EXPECT ONLY SNOW...WITH SFC TEMPS MAXING OUT IN THE
LOW TO MID 20F DEGREE RANGE /MONDAY/ AND 850MB TEMPS TOPPING OUT
AROUND -15C EAST EARLY THURSDAY NIGHT...AND AGAIN SUNDAY THROUGH
MONDAY AROUND -12 TO -15C.
WILL CONTINUE TO HAVE LES OVER THE W HALF OF UPPER MI THURSDAY
NIGHT. AMOUNTS ARE STILL IN QUESTION. MAY NEED TO EXTEND THE CURRENT
LES ADVISORY FOR ANOTHER 6-12HRS IF THE 3-5IN OF SNOW FALL OVER
KEWEENAW...N HOUGHTON...AND FAR W ONTONAGON COUNTY THURSDAY NIGHT.
THE LES PARAMETER OFF THE GFS REMAINS AT OR ABOVE 2 THROUGH 06Z
FRIDAY. WILL LET LATER SHIFTS DISCUSS THE NEED...AS THE WINDS
DIMINISH SIGNIFICANTLY...BUT STILL GUSTING TO AROUND 20-25KTS
OVERNIGHT. THE WEAKENING SFC TROUGH WILL LINGER ACROSS THE UPPER
GREAT LAKES THROUGH SATURDAY...WITH WINDS SLOWLY MOVING MORE
OFFSHORE SATURDAY NIGHT. UNTIL THEN...LES WILL LINGER MAINLY ACROSS
THE KEWEENAW PENINSULA.
KEPT MENTION OF THE COLDEST TEMPS OF THE SEASON IN THE HWO FOR
THURSDAY NIGHT THROUGH SATURDAY MORNING. AT THIS POINT IT LOOKS LIKE
A WIND CHILL ADVISORY MAY NOT BE NEEDED FOR FRIDAY NIGHT INTO
SATURDAY MORNING...AS THE LOWEST VALUES FLIRT WITH -25C OVER THE SW
CORNER OF THE CWA.
STRONG SFC HIGH OVER SW CANADA FRIDAY WILL PUSH ACROSS THE NORTHERN
AND CENTRAL PLAINS FRIDAY NIGHT INTO EARLY SATURDAY...BEFORE
BUILDING ACROSS THE GREAT LAKES REGION. ENDED UP SPLITTING UP SOME
OF THE MORE EXTENDED POPS AS A RESULT...FOR SATURDAY THROUGH SUNDAY.
THE NEXT ROUND OF SNOW WILL SLIDE BACK IN SUNDAY NIGHT...WITH LIKELY
POPS OVER THE E HALF...AS THE HIGH EXITS ACROSS THE NEW ENGLAND
STATES AND LOW PRESSURE NEARS FROM THE LOWER AND CENTRAL MS VALLEY.
THE SFC LOW LOOKS TO CROSS LAKE HURON AROUND 12Z MONDAY...DEEPENING
AS IT MOVES TO S QUEBEC MONDAY AFTERNOON/EVENING. THIS WILL BRING
ABOUT ANOTHER ROUND OF W TO NW WINDS...WITH GALES AGAIN POSSIBLE
ACROSS LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1246 AM EST THU DEC 5 2013
LOW PRESSURE LIFTING NORTHEASTWARD OUT OF THE AREA WILL ALLOW SOME
LINGERING DRIZZLE THROUGH 08Z/05 KEEPING VSBY DOWN AT KSAW BEFORE A
COLD FRONT PUSHES INTO THE AREA. WINDS ARE EXPECTED TO BECOME
WESTERLY THROUGH THE OVERNIGHT HOURS WITH GUSTS INCREASING TO NEARLY
30 KNOTS AT TIMES. IWD AND CMX MAY ALSO HAVE SOME LINGERING DRIZZLE
BEFORE THE STRONGER...COLDER WINDS PUSH IN DROPPING CEILINGS DOWN AND
INCREASING THE POTENTIAL FOR LAKE EFFECT SNOW...ESPECIALLY DURING THE
DAY THURSDAY. THE PREVIOUSLY MENTIONED GUSTY WINDS MAY ALSO ACT TO
REDUCE VISIBILITY AT CMX AND IWD IF BLSN BECOMES AN ISSUE. &&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 317 PM EST WED DEC 4 2013
LOW PRESSURE OVER WISCONSIN WILL DEEPEN ACROSS CENTRAL AND EASTERN
LAKE SUPERIOR OVERNIGHT...AND EXIT NORTHEAST ACROSS JAMES BAY WHILE
FURTHER DEEPENING THURSDAY NIGHT. THE PERIOD OF STRONG WINDS WILL
CONTINUE THROUGH THURSDAY NIGHT...WITH OUR INITIAL E TO NE WINDS
/GALES TO 35KTS OVER W LAKE SUPERIOR/ BECOMING OUT OF THE S AND SW
FOR ALL BUT FAR W LAKE SUPERIOR OVERNIGHT...BEFORE W GALES OF 35 TO
40 KNOTS START UP THURSDAY MORNING THROUGH THURSDAY NIGHT.
A STRONG ARCTIC HIGH PRESSURE SYSTEM OVER WESTERN CANADA ON THURSDAY
WILL SLIDE ACROSS THE NORTHERN PLAINS ON SATURDAY...AND ACROSS THE
GREAT LAKES SUNDAY. THE HIGH WILL EXIT ACROSS THE NEW ENGLAND STATES
WHILE WEAKENING SLIGHTLY ON MONDAY. EXPECT LOW PRESSURE OVER THE
LOWER MISSISSIPPI VALLEY SUNDAY TO DEEPEN AND SURGE NORTHWARD ACROSS
LAKE HURON LATE SUNDAY NIGHT INTO MONDAY. W TO NW GALES TO 35KTS
WILL BE POSSIBLE AGAIN MONDAY THROUGH TUESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 AM EST /MIDNIGHT CST/ EARLY THIS
MORNING FOR MIZ002-009>011-084.
LAKE EFFECT SNOW ADVISORY FROM 4 AM EARLY THIS MORNING TO 7 PM
EST THIS EVENING FOR MIZ001-003.
WINTER WEATHER ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR
MIZ001-003.
WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ004-
005.
LAKE SUPERIOR...
GALE WARNING FROM 6 AM THIS MORNING TO 4 AM EST FRIDAY FOR
LSZ265>267.
GALE WARNING UNTIL 4 AM EST FRIDAY FOR LSZ263-264.
GALE WARNING FROM 8 AM THIS MORNING TO 7 PM EST THIS EVENING FOR
LSZ246>248-250-251.
GALE WARNING FROM 5 AM EST /4 AM CST/ EARLY THIS MORNING TO 7 PM
EST /6 PM CST/ THIS EVENING FOR LSZ241>245.
GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ162.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...KF
AVIATION...KEC
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1203 AM EST THU DEC 5 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 400 PM EST WED DEC 4 2013
20Z SFC CHART INDICATES ELONGATED SFC TROUGH FROM WCNTRL WI INTO
NORTHEAST IA WITH MSLP OF 998MB. WV AND RUC FCST SHOWS SHORTWAVE
PUSHING ACROSS SOUTHERN MINNESOTA. WAVE IS EXPECTED TO LIFT TOWARD
NORTHWEST WI WHILE DEEPENING OVERNIGHT. WARM AIR ADVECTION IN FULL
SWING AHEAD OF MAINLY 850MB LOW LIFTING INTO NW WISCONSIN. RUC13 AND
NAM12 HAVE DONE NICE JOB WITH THE WARM LAYER AT H9-H85 TODAY AND
BOTH SHOW H85 TEMPS OVER 2C REACHING NORTH OF ALL CWA BY 00Z.
SOUNDINGS OVER US CURRENTLY WOULD SUGGEST MAINLY FZRA BUT LINGERING
COLD POCKET NEAR SFC /TEMPS STILL IN MID-UPR 20S/ IS ALLOWING SLEET
TO HANG ON LONGER. CURRENTLY SNOW IS STILL FALLING OVER KEWEENAW
PENINSULA BUT IS EVEN STARTING TO MIX WITH FREEZING RAIN AND SLEET
OVER PORTIONS OF WESTERN UPR MICHIGAN. PLAN FOR EVENING IS THAT
MIXED FREEZING RAIN/SLEET/SNOW WILL CHANGE TO MAINLY FREEZING RAIN
AND SLEET WHILE MOSTLY FREEZING RAIN OR EVEN JUST RAIN OCCURS FOR
CNTRL CWA...ESPECIALLY CLOSER TO LK MICHIGAN SHORE. IF HEAVIER
PRECIP WAS EXPECTED OVR CNTRL THIS EVENING...ICING COULD BE BIGGER
ISSUE. RIGHT NOW...APPEARS THAT HEAVIER PRECIP IS GOING TO OCCUR IN
STRIPE FROM SOUTHERN MINNESOTA TOWARD WESTERN LK SUPERIOR IN AREAS
OF STRONGEST PVA/DIVERGENCE ALOFT JUST AHEAD OF TRACK OF SHORTWAVE.
GIVEN TREND TO MORE FZRA THOUGH...INCREASED ICE ACCUMS OVER INTERIOR
WEST AND CNTRL TO 0.10-0.20 INCHES THROUGH THE EVENING.
AS MID-LEVEL DRYING IN THE H7-H6 LAYER ARRIVES 03Z-06Z OVER THE
SOUTH AND AFTER 06Z IN THE NORTH...EXPECT WINTRY MIX OF PRECIP TO
TAPER OFF TO MORE OF A DRIZZLE/FREEZING DRIZZLE. ACTUALLY HEADLINES
SO FAR ARE WORKING OUT PRETTY WELL. DID HAVE TO GO WITH MORE SLEET
AND FREEZING RAIN AS WARM AIR WORKED IN QUICKER...BUT OVERALL IDEA
OF WINTRY MIX IS COVERED WITH GOING WINTER WEATHER ADVY. TIMING FOR
ENDING OF ADVY SEEMS GOOD AS WELL. ONLY POSSIBLE TROUBLE SPOTS WILL
IN THE INTERIOR CNTRL AND EAST THIS EVENING DUE TO ICING IF HEAVIER
PRECIP ENDS UP BLOSSOMING TO THE EAST OF PRIMARY SHORTWAVE. SOME
SHORT TERM HIGHER-RES MODELS INDICATE EXPANSION OF PRECIP OVER
SCNTRL THIS EVENING...BUT RADAR TRENDS UPSTREAM NOT REALLY SHOWING
THIS. IF SFC TEMPS STAY BLO FREEZING THAT AREA WILL NEED TO BE
WATCHED FOR POSSIBLE ADVY.
NOW ONTO LATE TONIGHT AND THURSDAY. MAIN ISSUE SEEMS TO BE LK EFFECT
AND BLOWING SNOW ON THE KEWEENAW. WEST WINDS MAY GUST OVER 40 MPH AT
TIMES LEADING TO THE BLSN/POOR VISIBILITY...PROBABLY 1/4-1/2SM AT
TIMES OVER PORTIONS OF THE KEWEENAW. LARGER SCALE FORCING BECOMES
NEGATIVE BUT THERE IS A LOT OF LINGERING MOISTURE BLO H8 WITH
COOLING AT INVERSION TOP TO -16C OR SO BY MIDDAY. GIVEN LK SUPERIOR
WATER TEMPS AROUND 3-4C THIS GIVES MORE THAN SUFFICIENT OVER-WATER
INSTABILITY FOR AT LEAST MODERATE LK EFFECT SNOW SHOWERS. WSW WINDS
OVER LAND WITH MORE OF A WESTERLY WIND OVER LK SUPERIOR INDICATES
STRONGER CONVERGENCE AREA SETS UP ACROSS KEWEENAW. SNOW AMOUNTS WILL
BE HELD DOWN SOME BY LOWER SLR/S AS THERE IS A LOT OF FRACTURING OF
SNOWFLAKES DUE TO THE STRONG WINDS. EXPECT ADVY LEVEL SNOWS OF 3-5"
OR 4-7" WITH A LOT OF WIND/BLSN. WILL ISSUE A SEPARATE LAKE EFFECT
SNOW ADVY FOR LATE TONIGHT THROUGH THURSDAY...GOING INTO PLACE RIGHT
WHEN THE CURRENT WINTER WEATHER ADVY FOR THE MESSY MIX OF SNOW/SLEET
AND FREEZING RAIN DIMINISHES.
AND FINALLY FOR LATE TONIGHT INTO THURSDAY...AWAY FM THE
KEWEENAW...MAIN ISSUE WILL BE COLD AIR PUSHING IN FM THE WEST.
ALREADY SEEING THIS ARCTIC AIR POURING ACROSS THE DAKOTAS THIS AFTN.
EXPECT SLOWLY FALLING TEMPERATURES THROUGH THE DAY AS THE COLD WORKS
EAST...WITH READINGS LIKELY INTO THE UPPER SINGLE DIGITS BY EVENING
OVER THE FAR WEST CWA. THIS COLDER AIR WILL ALSO FREEZE ANY
LINGERING SLUSH AND WATER IS ON THE ROADS AND SIDEWALKS...WHICH
COULD RESULT IN TOUGHER TRAVEL CONDITIONS IN SPOTS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 456 PM EST WED DEC 4 2013
THE EASY PART OF THIS FCST PERIOD WILL BE THE LACK OF MIXED
PRECIPITATION. EXPECT ONLY SNOW...WITH SFC TEMPS MAXING OUT IN THE
LOW TO MID 20F DEGREE RANGE /MONDAY/ AND 850MB TEMPS TOPPING OUT
AROUND -15C EAST EARLY THURSDAY NIGHT...AND AGAIN SUNDAY THROUGH
MONDAY AROUND -12 TO -15C.
WILL CONTINUE TO HAVE LES OVER THE W HALF OF UPPER MI THURSDAY
NIGHT. AMOUNTS ARE STILL IN QUESTION. MAY NEED TO EXTEND THE CURRENT
LES ADVISORY FOR ANOTHER 6-12HRS IF THE 3-5IN OF SNOW FALL OVER
KEWEENAW...N HOUGHTON...AND FAR W ONTONAGON COUNTY THURSDAY NIGHT.
THE LES PARAMETER OFF THE GFS REMAINS AT OR ABOVE 2 THROUGH 06Z
FRIDAY. WILL LET LATER SHIFTS DISCUSS THE NEED...AS THE WINDS
DIMINISH SIGNIFICANTLY...BUT STILL GUSTING TO AROUND 20-25KTS
OVERNIGHT. THE WEAKENING SFC TROUGH WILL LINGER ACROSS THE UPPER
GREAT LAKES THROUGH SATURDAY...WITH WINDS SLOWLY MOVING MORE
OFFSHORE SATURDAY NIGHT. UNTIL THEN...LES WILL LINGER MAINLY ACROSS
THE KEWEENAW PENINSULA.
KEPT MENTION OF THE COLDEST TEMPS OF THE SEASON IN THE HWO FOR
THURSDAY NIGHT THROUGH SATURDAY MORNING. AT THIS POINT IT LOOKS LIKE
A WIND CHILL ADVISORY MAY NOT BE NEEDED FOR FRIDAY NIGHT INTO
SATURDAY MORNING...AS THE LOWEST VALUES FLIRT WITH -25C OVER THE SW
CORNER OF THE CWA.
STRONG SFC HIGH OVER SW CANADA FRIDAY WILL PUSH ACROSS THE NORTHERN
AND CENTRAL PLAINS FRIDAY NIGHT INTO EARLY SATURDAY...BEFORE
BUILDING ACROSS THE GREAT LAKES REGION. ENDED UP SPLITTING UP SOME
OF THE MORE EXTENDED POPS AS A RESULT...FOR SATURDAY THROUGH SUNDAY.
THE NEXT ROUND OF SNOW WILL SLIDE BACK IN SUNDAY NIGHT...WITH LIKELY
POPS OVER THE E HALF...AS THE HIGH EXITS ACROSS THE NEW ENGLAND
STATES AND LOW PRESSURE NEARS FROM THE LOWER AND CENTRAL MS VALLEY.
THE SFC LOW LOOKS TO CROSS LAKE HURON AROUND 12Z MONDAY...DEEPENING
AS IT MOVES TO S QUEBEC MONDAY AFTERNOON/EVENING. THIS WILL BRING
ABOUT ANOTHER ROUND OF W TO NW WINDS...WITH GALES AGAIN POSSIBLE
ACROSS LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1202 AM EST THU DEC 5 2013
COMPLICATED FORECAST CONTINUES WITH COLD AIR COMING IN. SNOW
CONTINUE AT IWD AND CMX THROUGH THE PERIOD WITH SOME LAKE EFFECT
SNOW. USED CONSENSUS GUIDANCE FOR CIGS/VIS AND MORE CLIMATOLOGY FOR
LAKE EFFECT SNOW LATE IN THE PERIOD FOR IWD AND CMX. LIFR CONDITIONS
WILL IMPROVE OVERNIGHT AT ALL SITES AS COLD AIR MOVES IN AND THEN
SHOULD STAY MVFR AT IWD AND SAW THROUGH THE PERIOD. GUSTY WINDS AND
BLOWING SNOW WILL KEEP CMX DOWN TO LIFR LATE TONIGHT THROUGH THE
REST OF THE FORECAST PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 317 PM EST WED DEC 4 2013
LOW PRESSURE OVER WISCONSIN WILL DEEPEN ACROSS CENTRAL AND EASTERN
LAKE SUPERIOR OVERNIGHT...AND EXIT NORTHEAST ACROSS JAMES BAY WHILE
FURTHER DEEPENING THURSDAY NIGHT. THE PERIOD OF STRONG WINDS WILL
CONTINUE THROUGH THURSDAY NIGHT...WITH OUR INITIAL E TO NE WINDS
/GALES TO 35KTS OVER W LAKE SUPERIOR/ BECOMING OUT OF THE S AND SW
FOR ALL BUT FAR W LAKE SUPERIOR OVERNIGHT...BEFORE W GALES OF 35 TO
40 KNOTS START UP THURSDAY MORNING THROUGH THURSDAY NIGHT.
A STRONG ARCTIC HIGH PRESSURE SYSTEM OVER WESTERN CANADA ON THURSDAY
WILL SLIDE ACROSS THE NORTHERN PLAINS ON SATURDAY...AND ACROSS THE
GREAT LAKES SUNDAY. THE HIGH WILL EXIT ACROSS THE NEW ENGLAND STATES
WHILE WEAKENING SLIGHTLY ON MONDAY. EXPECT LOW PRESSURE OVER THE
LOWER MISSISSIPPI VALLEY SUNDAY TO DEEPEN AND SURGE NORTHWARD ACROSS
LAKE HURON LATE SUNDAY NIGHT INTO MONDAY. W TO NW GALES TO 35KTS
WILL BE POSSIBLE AGAIN MONDAY THROUGH TUESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 AM EST /MIDNIGHT CST/ EARLY THIS
MORNING FOR MIZ002-009>011-084.
LAKE EFFECT SNOW ADVISORY FROM 4 AM EARLY THIS MORNING TO 7 PM
EST THIS EVENING FOR MIZ001-003.
WINTER WEATHER ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR
MIZ001-003.
WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ004-
005.
LAKE SUPERIOR...
GALE WARNING FROM 6 AM THIS MORNING TO 4 AM EST FRIDAY FOR
LSZ265>267.
GALE WARNING UNTIL 4 AM EST FRIDAY FOR LSZ263-264.
GALE WARNING FROM 8 AM THIS MORNING TO 7 PM EST THIS EVENING FOR
LSZ246>248-250-251.
GALE WARNING FROM 5 AM EST /4 AM CST/ EARLY THIS MORNING TO 7 PM
EST /6 PM CST/ THIS EVENING FOR LSZ241>245.
GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ162.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...KF
AVIATION...07
MARINE...KF
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
105 AM CST Thu Dec 5 2013
.UPDATE...
Issued at 1249 AM CST THU DEC 5 2013
We have inserted a slight chance for a wintry mix overnight from
southwestern Missouri up towards Lake of the Ozarks and Rolla. The
last few runs of the NAM and RAP have hinted at QPF output late
tonight. They appear to be hitting on forcing along the 850 mb
front. There may also be aid from continued upslope flow along the
Ozark Plateau. Point soundings indicate that parcels lifted from
850 mb would be briefly buoyant. As for precipitation types...we
went with a mixture of light freezing rain and sleet. Freezing
drizzle will also be possible as any precipitation will likely
occur right on the edge of appreciable cloud ice. A very thin
glaze of ice will be possible along with a dusting of sleet if
this precipitation materializes. This may result in localized slick
spots on area roadways during the predawn hours.
&&
.SHORT TERM...(Through This Evening)
Issued at 138 PM CST WED DEC 4 2013
A cold front was in the process of making its way east across the
region this afternoon. Temperatures ahead of the front were in the
lower 60s. Behind the front, temperatures had fallen to around 40
degrees. The cold air will filter into the region through this
evening, bringing an abrupt end to the mild weather the region has
seen over the past few days.
As the front pushes east, the rapid drop in temperatures was
allowing for the development of advection fog. Visibilities along
and just behind the front were dropping to less than a mile. The
thickest fog will remain closely associated with the front, with
visibilities improving behind the front. Some light fog and low
clouds will remain over the region after the front moves through
with winds turning to the northwest and temperatures falling
through the evening and overnight.
.LONG TERM...(Thursday through Wednesday)
Issued at 138 PM CST WED DEC 4 2013
Cold air will continue to build into the area during the overnight
hours tonight, with temperatures dropping below freezing in most
locations during the predawn hours. By 12z tomorrow morning, expect
all but the far southeastern corner of the CWA to be below freezing,
with areas along and north of I-44 well into the mid to low 20s.
Precipitation should begin to develop during the morning hours on
Thursday, with a steady increase in both coverage and intensity from
mid morning through mid afternoon as the upper level jet intensifies
over the Midwest, with the Ozarks well within its right entrance
region. Onset of precip appears to be a little slower, with the
heaviest activity afternoon tomorrow. With some dry air to be
overcome, especially the further north and west that one goes in
the CWA, it may take a bit for precip to reach the ground,
especially along the I-44 corridor. Once it does however, given
cold ground temps, would expect to see rapid increases on area
roadways.
Initial precipitation type remains most likely to be a mix of snow,
sleet, and perhaps a little freezing rain along the I-44 corridor,
with a mix of sleet, rain, and freezing rain across far south
central Missouri, before enough cold air builds in for a change over
the freezing rain and sleet, and then sleet and snow, and eventually
all snow by tomorrow evening. Guidance continues to trend colder
aloft, and thus believe the vast majority of freezing rain
accumulations will remain south of the CWA. Will continue to
advertise a glaze to tenth of an inch of freezing rain along and
southeast of an Anderson to Marshfield to Salem line. Along with
the ice accumulations, snow/sleet accumulations should be fairly
minor during the daytime hours tomorrow, with a quarter inch to one
inch of combined snow and sleet by late afternoon. Again, however,
it`s important to note that with cold temps in place before the
onset of precipitation, immediate accumulations and impacts are
expected tomorrow during the daytime hours.
By tomorrow evening, enough cold air should be in place to change
precipitation over to all snow for all but the extreme southeastern
portion of the forecast area. That area should finally change over
to all snow between midnight and 3 AM. After a relative lull in
activity during the evening hours, another wave of snow should
overspread the area as the upper jet increases in intensity and
another shortwave arrives from the Southern Plains. Will need to
watch the Thursday night/Friday morning snow carefully for the
potential for higher accumulations that what is currently forecast,
given the potential for much higher than usual snow to liquid ratios
due to the very cold temperatures. For this forecast, generally
used a 13:1-17:1 ratio, depending in temperature. In addition to
SLR issues, cross sections indicate the potential for some lower
static stability and possible development of slantwise convection,
especially if an axis of mid level frontogenesis develops far enough
north to tap into the CSI. Snow should end during the day Friday as
the mid level wave swings through.
Once all is said and done Friday evening, storm total snow
accumulations should range from 1-3 inches north of I-44, 2-5 along
the greater I-44 corridor, and 4-6 inches across southern and south
central Missouri. A glaze to tenth of an inch of freezing rain will
also be possible Thursday across south central Missouri.
With heavier accumulations and more substantial mixed precipitation
across southern/south central Missouri, will go ahead and upgrade
the Winter Storm Watch area to a Winter Storm Warning. North of the
Warning, a Winter Weather Advisory will be issued as far north as
roughly U.S. 54. The main impact for this event will likely be to
roadways/travel, especially considering what should be almost
immediate accumulations once precipitation begins on Thursday.
Friday night and Saturday look to be dry across the region, as very
cold and dry air builds into the area. Temperatures Friday night
will fall into the single digits, especially with fresh snow cover
in place. Highs Saturday will only warm into the low to perhaps mid
20s.
Another wave of precipitation will overspread the area Saturday
night into Sunday, most likely in the form of snow. A few
additional inches of snowfall will be possible with this system. The
majority of this activity looks to end by Monday morning.
After relative "warmth" in the upper 20s on Sunday, the coldest air
in nearly two and a half years will overspread the area for Monday
and Tuesday. For now, highs both days look to be in low 20s, with
low temperatures in the single digits, approaching zero. It is
worth noting that some guidance does bring in even colder readings,
with the possibility of later forecasts taking low temperatures
below zero Monday and Tuesday mornings in some spots. Much will
depend on snow cover both here and to our north, so this will
certainly be something to keep an eye on over the next few days.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1139 PM CST WED DEC 4 2013
Ceilings will continue to hover between high-end IFR and low-end
MVFR for the early overnight period. Flight conditions will then
briefly improve as we approach sunrise. A storm system will then
spread a wintry mix of precipitation into southern Missouri on
Thursday. It appears that a mixture of sleet and snow will change
to all snow at Springfield with precipitation falling from late
morning through the afternoon. Joplin will be right on the
northern edge of the precipitation and will also see a sleet and
snow mixture quickly changing to all snow. Branson will see mixed
precipitation longer before finally changing to all snow from mid
to late afternoon. IFR conditions can be expected with steadier
snow, with LIFR possible at Branson where snow may be moderate to
heavy at times. The snow will then end by early evening with
ceilings remaining in the MVFR to high-end IFR range.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...WINTER STORM WARNING from 9 AM this morning to 6 PM CST Friday
FOR MOZ095>098-101>106.
WINTER WEATHER ADVISORY from 9 AM this morning to 6 PM CST
Friday FOR MOZ057-058-069>071-077>083-088>094.
KS...WINTER WEATHER ADVISORY from 9 AM this morning to 6 PM CST
Friday FOR KSZ097-101.
&&
$$
UPDATE...Schaumann
SHORT TERM...Hatch
LONG TERM...Boxell
AVIATION...Schaumann
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1132 PM CST WED DEC 4 2013
.EQUIPMENT...
OUR RADAR FAILED AT THE TOP OF THE HOUR AND WILL NOT COME BACK ON-
LINE. WE ARE IN THE PROCESS OF CONTACTING TECHS.
.UPDATE...
ISSUED AT 1132 PM CST WED DEC 4 2013
HOURLY TEMPS AND DEWPOINTS WERE RUNNING A LITTLE TOO LOW COMPARED
TO REALITY. WE SHOULD BE BACK ON-TRACK FOR THE NEXT FEW HOURS. SKY
COVER WAS ALSO INCREASED TO 100% WHERE SKIES ARE CLOUDY AND WILL
CONTINUE TO BE THE NEXT FEW HOURS.
THE LAST OF THE LIGHT SNOW IS ALONG AND E OF A LINE FROM STOCKTON
KS TO MANKATO TO HEBRON. IT SHOULD BE COMPLETELY OUT OF THE FCST
AREA BY 2 AM.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 257 PM CST WED DEC 4 2013
AN ARCTIC AIRMASS HAS SETTLED ACROSS THE NORTHERN AND CENTRAL
PLAINS...AND H85 TEMPS ARE ON THE ORDER OF 2 TO 3 STANDARD
DEVIATIONS BELOW NORMAL FOR THIS TIME OF YEAR. TEMPERATURES THIS
AFTERNOON HAVE STRUGGLED IN THE ARCTIC AIR AND READINGS AVERAGE IN
THE TEENS/20S ATTM. WINDS CONTINUE TO REMAIN STEADY/GUSTY IN A
TIGHT PRESSURE GRADIENT WITH A DEPARTING SFC LOW ACROSS EASTERN
IOWA AND A 1035MB SURFACE HIGH BUILDING SOUTHEAST FM MONTANA. THE
COMBINATION OF THE GUSTY WINDS AND COLD TEMPS HAVE RESULTED IN
WINDS CHILLS IN THE SINGLE DIGITS THIS AFTERNOON. SNOW FLURRIES
ACROSS OUR EASTERN ZONES CONTINUE WILL CONTINUE TO DIMINISH AS WE
HEAD THRU THE REMAINDER OF THE AFTN IN A SUBSIDENT/CLEARING AREA.
THIS EVENING...A 150KT H25 JET EMERGES FROM THE CENTRAL ROCKIES
AND CROSSES THRU NEBRASKA AND A MID LEVEL TROUGH TRANSLATES ACROSS
THE CENTRAL PLAINS. COLD AIR IS REINFORCED WITH THIS NEXT TROUGH
MOVING THRU THIS EVENING AND A BAND OF MID LEVEL FRONTOGENESIS IS
PROGGED ACROSS OUR SOUTHERN ZONES. IN FAVORABLE JET DYNAMICS AND
PRESENCE OF THE FRONTOGENESIS...A NARROW CORRIDOR OF BANDED
SNOWFALL IS EXPECTED TO DEVELOP DURING THE EVENING. MODELS ARE NOT
IN COMPLETE AGREEMENT ON WHERE THIS BAND WILL SET UP WITH THE GFS
THE FARTHEST NORTH WITH THE BAND...THE 12Z NAM WAS THE FARTHEST
SOUTH WITH THE BAND BUT HAS TRENDED NORTHWARD WITH THE 18Z RUN.
EARLIER RUNS OF THE RAP WERE MORE SIMILAR TO THE CURRENT 18Z
NAM...HOWEVER THE LATEST RUNS OF THE RAP HAVE TRENDED FARTHER
SOUTH INTO CENTRAL KANSAS WITH THE POSITION. THIS BEING
SAID...NORTH CENTRAL KANSAS IS STILL THE MOST FAVORABLE LOCATION
FOR SNOWFALL THIS EVENING. POPS HAVE BEEN INCREASED AND WHERE BAND
SETS UP...SOME HALF INCH SNOWFALL AMOUNTS OR SO ARE NOT OUT OF THE
QUESTION. FARTHER NORTH OF THE BAND...FLURRIES ARE POSSIBLE UNTIL
THE MID LEVEL TROUGH AXIS PASSES TO THE EAST BY AROUND MIDNIGHT OR
SHORTLY THEREAFTER.
OVERNIGHT TEMPERATURES WILL REMAIN FRIGID AND CLOUDS BEGIN TO SCOUR
BEFORE DAYBREAK. HAVE WENT WITH LOW TEMPS IN THE SINGLE DIGITS
ABOVE ZERO TONIGHT AND WHEN COMBINED WITH THE STEADY NORTHWESTERLY
WINDS...WIND CHILL READINGS WILL DROP TO ROUGHLY 8 TO 18 DEGREES
BELOW ZERO ACROSS OUR CWA. THE COLDEST READINGS WILL BE ACROSS OUR
NW ZONES...AND THE 18 BELOW VALUES REMAIN SHY OF WIND CHILL ADVISORY
CRITERIA SO WILL HOLD OFF ON HEADLINE AND CONTINUE TO MENTION COLD
WIND CHILLS IN THE HWO.
THE ARCTIC AIRMASS WILL REMAIN IN PLACE ON THURSDAY...WITH FRIGID
-18C AIR SETTLING IN AT H85. THE SFC RIDGE AXIS WILL CONTINUE TO
NOSE SOUTHEAST ONTO THE PLAINS AND DRY AND VERY COLD WEATHER IS
FORECAST. TEMPS WILL CONTINUE TO STRUGGLE IN THE COLD AIRMASS AND
WILL GIVE TEMPS ABOUT A 10 DEGREE RISE FROM MORNING LOWS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 257 PM CST WED DEC 4 2013
THURSDAY NIGHT THROUGH WEDNESDAY. MAIN FORECAST
CONCERNS WILL BE CHANCE FOR SNOW SATURDAY NIGHT THROUGH SUNDAY NIGHT
AND COLD TEMPERATURES THROUGH THE PERIOD.
A COLD SURFACE HIGH PRESSURE SYSTEM WILL PUSH INTO THE AREA FOR
THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE CENTER OF THE HIGH WILL
REMAIN NORTH AND EAST OF THE AREA AND WINDS WILL CONTINUE TO BE
AROUND 5 TO 15 MPH. WITH THE TEMPERATURES ALREADY IN THE SINGLE
DIGITS ABOVE AND BELOW ZERO...THE WIND CHILL VALUES WILL DROP INTO
THE -10 TO -20 DEGREE RANGE ACROSS THE AREA.
ON SATURDAY THE SURFACE HIGH MOVES OFF TO THE EAST AND WINDS TURN TO
THE SOUTH. AN UPPER LEVEL WAVE APPROACHES THE AREA FROM THE
SOUTHWEST. THERE IS INCREASING MOISTURE ACROSS THE AREA AND CLOUDS
WILL INCREASE.
SATURDAY NIGHT THROUGH SUNDAY NIGHT THE UPPER LEVEL WAVE WILL MOVE
THROUGH THE REGION. STARTING SATURDAY NIGHT THERE IS WARM ADVECTION
OF MOIST AIR OVER THE COLD SURFACE. EXPECT SNOW TO START ACROSS THE
AREA DURING THE EVENING AND CONTINUE INTO SUNDAY. THE BEST CHANCES
WILL LIKELY BE LATE SATURDAY NIGHT INTO SUNDAY MORNING. MODELS HAVE
SOME VARIABLE QPF AMOUNTS BUT IT LOOKS LIKE THERE WILL BE
ACCUMULATING SNOWFALL. WITH THE COLD TEMPERATURES THERE WILL MOST
LIKELY BE LIGHT FLUFFY SNOWFALL. AN ADVANTAGE IS THAT CURRENTLY
THERE IS NOT SIGNIFICANT WIND WITH THE SYSTEM. BY SUNDAY EVENING THE
MAIN UPPER WAVE IS THROUGH THE AREA AND THE SNOWFALL WILL GRADUALLY
COME TO AN END SUNDAY NIGHT.
A COLD SURFACE HIGH PRESSURE SYSTEM MOVES INTO THE SOUTHERN PLAINS
ON MONDAY AND COLD TEMPERATURES WILL CONTINUE ACROSS THE AREA MONDAY
INTO TUESDAY. TUESDAY NIGHT ANOTHER WEAK UPPER LEVEL WAVE APPROACHES
THE AREA. THE MAIN WAVE IS FURTHER TO THE NORTH. MOST OF THE
MOISTURE IS FURTHER NORTH AND NOT MUCH CHANGE FROM MONDAY AND
TUESDAY. THE ONLY CHANGE WILL BE A POTENTIAL FOR SOME SLIGHTLY
WARMER TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1132 PM CST WED DEC 4 2013
REST OF TONIGHT: VFR MID-LEVEL CIGS WILL BECOME SCT...REVEALING
SCT-BKN CIRRUS AT 25K FT. NW WINDS WILL CONTINUE GUSTING UP TO 32
KTS WITH A SLOW DIMINISHING TREND. CONFIDENCE: HIGH.
THU: VFR WITH SCT-BKN 25K FT CIRRUS IN THE MORNING. A FEW STRATOCU
COULD DEVELOP AROUND 3K FT AFTER 17Z. NW WINDS 10-15 KTS.
CONFIDENCE: HIGH.
THU EVE: VFR WITH SCT MID-LEVEL CLOUDS AROUND 10K FT BECOMING A
CIG BY MIDNIGHT. CONFIDENCE: MEDIUM.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
EQUIPMENT...HALBLAUB
UPDATE...HALBLAUB
SHORT TERM...FAY
LONG TERM...JCB
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1107 PM MST WED DEC 4 2013
.AVIATION...
06Z TAF CYCLE
THE BAND OF SNOW WILL REINVIGORATE ACROSS THE WEST CENTRAL MTNS
LATE EVE/EARLY MORN AND SPREAD EASTWARD. HAVE GONE MUCH MORE
BULLISH FOR SNOW IMPACTS AT SAF/AEG/ABQ/LVS AND TCC. THE MAIN
PERIOD OF IMPACT ACROSS CENTRAL AREAS WILL RANGE BETWEEN 10Z TO
16Z ALTHOUGH SAF SHOULD LAST A BIT LONGER BASED ON THE LATEST
MODEL RUNS. LVS SHOULD LAST A GOOD CHUNK OF THE DAY WITH IFR
CONDITIONS PREDICTED. COULD VERY WELL SEE LIFR THERE. COULD SEE
BRIEF PERIODS OF IFR AT SAF/ABQ BUT NOT CURRENTLY IN THE FORECAST.
ALSO CANT RULE OUT AWW SNOW AMOUNTS OF 1...POSSIBLY 2 INCHES AT
ABQ. WILL BE MONITORING THAT VERY CLOSELY. WIND NOT NEARLY AS MUCH
OF A FACTOR TODAY WITH SLOWLY DIMINISHING SPEEDS ACROSS THE
EASTERN PLAINS REST OF TONIGHT.
50
&&
.PREV DISCUSSION...907 PM MST WED DEC 4 2013...
...ESTANCIA VALLEY AND EAST MOUNTAIN COMMUNITIES IN THE CROSSHAIRS
FOR HEAVY SNOW LATE TONIGHT THRU THURSDAY...
HAVE MADE SOME DETAILED CHANGES TO THE FORECAST GRIDS TO NARROW IN
ON EXPECTED AREA OF MOST SIGNIFICANT WINTER WX IMPACTS THRU THURSDAY
NIGHT. THE GREATEST CHALLENGE HAS BEEN WHERE A MESOSCALE BAND OF SNOW
SETS UP OVER CENTRAL NM THEN EXPANDS INTO A BROADER AREA OF SNOWFALL
ACROSS THE EASTERN PLAINS. THE LATEST 00Z NAM GUIDANCE AND RUC13 SHOW
THE BAND NOW FARTHER NORTH MORE LIKE SEVERAL ITERATIONS OF THE GFS/
CANADIAN AND ECMWF. GIVEN THIS NEW INFO AND A FOCUSED ATTEMPT AT QPF
WITH VERY SNOW RATIOS WE WILL EXPAND THE WARNING TO INCLUDE MUCH OF
THE EAST CENTRAL AND NE PLAINS...AS WELL AS ADD THE LOWER RIO GRANDE
VALLEY TO THE ADVISORY. COULD BE VERY INTERESTING FOR THE ESTANCIA
VALLEY AND EAST MTN COMMUNITIES WHERE THE DENDRITIC SNOW GROWTH
LAYER IS SPOT ON WITH THE BEST LIFT AND QPF...AND WITH HIGH SNOW
RATIOS WE MAY SEE SNOW RATES NEAR 1 OR EVEN 2 INCHES PER HOUR FOR A
FEW HOURS THURSDAY MORNING. AREAS OF NORTHWEST NM MAY BE DONE WITH
THIS EVENT HOWEVER WILL GIVE THE MID SHIFT ANOTHER SHOT TO LOOK AT
IT BEFORE DROPPING ANY HIGHLIGHTS.
GUYER
.PREV DISCUSSION...249 PM MST WED DEC 4 2013...
CURRENTLY...HIGH AMPLITUDE TROUGH FROM CENTRAL SASKATCHEWAN SOUTH
AND WEST TO SOUTHERN CALIFORNIA SWEEPING TOWARD NEW MEXICO...AS
SURFACE LOW DEEPENS OVER NORTHERN NEW MEXICO NEAR THE COLORADO
BORDER. ASSOCIATED COLD FRONT FESTOONED ACROSS THE NORTHERN
TIER...WITH SOUTHBOUND INCURSIONS OVER THE NORTHWEST PLATEAU AND
NORTHEAST PLAINS. SNOW STARTED SO FAR AT FARMINGTON AND
GALLUP...WITH WIDESPREAD SNOW ON TAP ACROSS MUCH OF THE FORECAST
AREA OVER THE NEXT 24 HOURS. WIND SPEEDS HAVE PEGGED WELL ABOVE
WARNING CRITERIA NEAR RUIDOSO...CLINES CORNERS...AND LAS
VEGAS...WITH GUSTS IN THE 40S MPH COMMON AND WIDESPREAD ACROSS THE
FORECAST AREA THIS AFTERNOON.
MODELS...IN REASONABLE AGREEMENT IN A STRONGLY FORCED PATTERN
THROUGH MIDWEEK NEXT WEEK. SIGNIFICANT DIFFERENCES IN PATTERN
EVOLUTION EMERGE FROM THURSDAY ONWARD NEXT WEEK. TROUGH STRETCHED
ACROSS THE INTERMOUNTAIN REGION AND MUCH OF THE WESTERN U.S. WILL
DIG TO THE COASTAL WATERS OF NORTHWESTERN MEXICO THROUGH THURSDAY
BEFORE MAKING EASTWARD SWEEP ACROSS NEW MEXICO THROUGH THURSDAY
NIGHT INTO FRIDAY MORNING. NEXT SHORTWAVE AMPLIFYING FROM ARCTIC
CANADA WESTWARD TOT HE PACIFIC NORTHWEST WILL DIG TO SOUTHERN
CALIFORNIA SATURDAY NIGHT AND CROSS OVER NEW MEXICO THROUGH SUNDAY
AND SUNDAY NIGHT. A QUICK TRAILING WAVE AMPLIFYING UPSTREAM FORM
CENTRAL COLORADO TO SOUTHERN ARIZONA MONDAY WILL MOVE ACROSS NEW
MEXICO THROUGH MONDAY NIGHT. BOTH ECMWF AND GFS SOLUTIONS NOW
PAINTING A DEEPER SHORTWAVE LATE TUESDAY OVER THE FOUR
CORNERS...AND DIFFER ON SPEED OF MOVING THIS FEATURE ACROSS NEW
MEXICO. ECMWF HAS THIS ONE OUTTA HERE BY WEDNESDAY NIGHT AS NEXT
WINTRY WAVE AMPLIFIES FROM ARCTIC CANADA TO CENTRAL CALIFORNIA ON
THURSDAY...AND DIGS THIS INTO A DEEP CLOSED LOW OVER SOUTHERN
SONORA IN NORTHERN MEXICO. GFS SOLUTION LACKS THIS DEEP
DRAMA...SHEARING PACIFIC NORTHWEST SHORTWAVES EASTWARD AND KEEPING
THEM CLEAR OF NEW MEXICO...WHICH SITS IN NORTHWEST FLOW THROUGH
THE REMAINDER OF THE WORK WEEK. ECMWF CLOSED LOW IS A NEW FEATURE
NEAR THE END OF THE FORECAST...THUS WILL SEE IF THIS REAPPEARS IN
FUTURE RUNS WITH BETTER CONTINUITY.
OVERNIGHT...COLD FRONT BLASTING SOUTHWARD WILL REACH THE SOUTHERN
TIER OVER THE EAST BY THURSDAY MORNING...WITH SOUTHBOUND PROGRESS
TO INTERSTATE 40 IN THE WEST. EASTERN WINDS WILL BACK OFF TO THE
EAST AND NORTHEAST...AND WESTWARD PUSH OF THE COLD WILL SET THE
STAGE FOR THE EASTERN SNOW EVENT TO COME. SNOW COVERAGE OVERNIGHT
WILL BECOME WIDESPREAD OVER THE NORTHERN HALF OF THE STATE...WITH
SNOW REACHING SOUTH OF INTERSTATE 40 OVER THE CONTINENTAL DIVIDE.
SANGRE DE CRISTO SUMMITS...ESPECIALLY THE SOUTHERN SUMMITS...WILL
BE MOST FAVORED FOR SNOW ACCUMULATION. PORTIONS OF CHAVES AND
ROOSEVELT COUNTIES MAY HAVE SOME FREEZING RAIN MIXED IN FOR AWHILE
AS ICY RAIN CHANGES OVER TO WET SNOW. 20 TO 30 DEGREE OVERNIGHT
TEMPERATURE DROPS TONIGHT COMPARED TO LAST NIGHT...WITH NORTHEAST
PLAINS SPOTS IN THE SINGLE DIGITS AND LOTS OF TEENS AND 20S
ELSEWHERE. WIND SPEEDS WILL RATCHET DOWN OVERNIGHT...BUT EVENING
GUSTS AND DEVELOPING SNOW OVER THE NORTH...AND OVER THE
CONTINENTAL DIVIDE WILL SET UP SOME OVERNIGHT BLOWING AND DRIFTING
OF SNOW. SNOW AMOUNTS COMING IN A LITTLE HIGHER THIS ROUND...AND
ACCOUNTING FOR ENHANCEMENTS ON THE EAST SLOPES OF THE CENTRAL
MOUNTAIN CHAIN...HAVE EXPANDED WINTER STORM WARNING COVERAGE THIS
ROUND TO THE ENTIRE LENGTH OF THE CENTRAL MOUNTAIN CHAIN...AND
PLACED MOST REMAINING ZONES UNDER WINTER WEATHER ADVISORIES OVER
THE NEXT 24 HOURS.
FOR THURSDAY...AXIS OF TROUGH ALOFT DIGGING INTO THE LOWER
COLORADO RIVER VALLEY AND NORTHERN BAJA CALIFORNIA...AS COLD PUSH
OVER THE EAST MAKES INTENSE EFFORT TO PUSH THROUGH THE CENTRAL
MOUNTAIN CHAIN AND OUT OVER THE RIO GRANDE VALLEY THROUGH THURSDAY
EVENING. VIGOROUS UP SLOPE FLOW AGAINST THE CENTRAL MOUNTAIN CHAIN
WILL SHIFT AND INTENSIFY SNOW COVERAGE OVER THE EAST...WITH
HEAVIEST ACCUMULATIONS OVER THE SOUTHERN SANGRE DE CRISTO
SUMMITS...AND PILED UP ON THE EAST SLOPES AND SUMMITS OF THE
MANZANO AND SANDIA MOUNTAINS...AND ON THE SOUTHWEST FACING SLOPES
BORDERING THE SAN FRANCISCO RIVER VALLEY IN CATRON COUNTY.
FREEZING RAIN REMAINS A THREAT IN THE SOUTHEAST...ESPECIALLY OVER
CHAVES AND SOUTHERN ROOSEVELT COUNTY. 30 TO 40 DEGREE TEMPERATURE
DROPS FROM THOSE LOGGED ON WEDNESDAY WILL BE COMMON ACROSS THE
EAST...WITH CENTRAL POINTS DROPPING 15 TO 25 DEGREES...AND EASTERN
SPOTS 8 TO 15 DEGREES BELOW WEDNESDAY TEMPERATURES. CLIMATE
COMPARISONS PUT THESE TEMPERATURES 30 TO 40 DEGREES BELOW EARLY
DECEMBER NORMALS OVER THE EAST...15 TO 25 DEGREES BELOW OVER THE
CENTRAL...AND 10 TO 20 DEGREES BELOW NORMAL OVER THE WEST.
THURSDAY WINDS WILL BE MUCH REDUCED...WITH SOME SOUTHWEST
BREEZINESS CONTINUING OVER THE SOUTH CENTRAL MOUNTAINS AND
CHUPADERA MESA DURING THE AFTERNOON. SNOW TAPERING OFF AND
SHIFTING TO THE SOUTHEAST THURSDAY NIGHT
FOR FRIDAY...BRISK AND BLUSTERY ZONAL FLOW ACROSS NEW MEXICO AS
WESTERN TROUGH MAKES FAST PASS ACROSS THE STATE...LEAVING ARCTIC
AIR MASS UNTOUCHED AS IT DEPARTS. ONLY MODEST TEMPERATURE
RELIEF...MOST OF THIS FOR THE FRIGID EAST...AS SKIES CLEAR AND
SNOW ENDS. COLD PUSH OUT OF THE CENTRAL PLAINS INTO NORTHEAST NEW
MEXICO LATE FRIDAY WILL REDEVELOP SNOW SHOWERS OVER THE
EAST...WITH MODEST ACCUMULATION SHOWING UP MOSTLY OVER THE
NORTHEAST PLAINS THROUGH FRIDAY NIGHT.
FOR SATURDAY...WESTBOUND COLD FRONT SLOSHED UP AGAINST THE CENTRAL
MOUNTAIN CHAIN...WITH AFTERNOON SOUTHWEST BREEZES STRENGTHENING
OVER THE WEST AND SOUTH CENTRAL...AND SOUTHERLY BREEZES WORKING
INTO THE NORTHEAST. ANOTHER DAY OF WIDESPREAD BUT LESS INTENSE
SNOW COVERAGE OVER THE EAST...WITH AMOUNTS AROUND AN
INCH...LOCALLY HIGHER IN OROGRAPHICALLY ENHANCED SPOTS.
TEMPERATURES REMAINING WELL BELOW EARLY DECEMBER NORMALS.
UPSTREAM...AMPLIFYING TROUGH SWEEPING THROUGH THE WESTERN U.S.
WILL DIG TO SOUTHERN CALIFORNIA BY SATURDAY AFTERNOON...AND INTO
SOUTHERN ARIZONA SATURDAY NIGHT.
OUTLOOK...SUNDAY THROUGH TUESDAY...TROUGH WILL BLUSTER AND SWEEP
ACROSS NEW MEXICO THROUGH THE DAY ON SUNDAY FOR CLEARING
SKIES...CONTINUED WELL BELOW NORMAL TEMPERATURES...AND LAST OF THE
SNOW TAPERING OFF OVER THE NORTHWEST ON MONDAY. SOME MODEST
TEMPERATURE MODERATION ON TUESDAY...WITH SPOTS REMAINING 10 TO 20
DEGREES BELOW MID DECEMBER NORMALS.
SHY
.FIRE WEATHER...
MODELS AGREE FAIRLY WELL WITH THE UPCOMING ACTIVE WEATHER PATTERN. A
PERSISTENT UPPER LEVEL LONG WAVE TROUGH WILL CONTINUE ACROSS NM
THROUGH THE NEXT WEEK. FOUR DISTINCT DISTURBANCES WITHIN THAT FLOW
WILL IMPACT THE STATE. THE FIRST DISTURBANCE IS ONGOING AND WILL
EXIT EAST THURSDAY MORNING. THE SECOND DISTURBANCE WILL QUICKLY
FOLLOW THE FIRST...CONTINUING SNOW SHOWERS ACROSS THE AREA THURSDAY
INTO FRIDAY MORNING. FLOW WILL BE IN TRANSITION FRIDAY...SETTING UP
A THIRD DISTURBANCE WILL DIG DEEPER INTO THE GREAT BASIN LATE
SATURDAY AND SWEEP ACROSS NM FROM THE WEST THROUGH SUNDAY NIGHT.
THIS WILL BE THE NEXT BEST PERIOD OF SIGNIFICANT SNOWFALL
ACCUMULATIONS AND WIND. THE FOURTH DISTURBANCE WILL PUSH SOUTHWARD
OUT OF THE CENTRAL ROCKIES MONDAY INTO TUESDAY...BUT BE FAIRLY
MOISTURE STARVED.
A PACIFIC COLD FRONT ACROSS NW NM ASSOCIATED WITH THE FIRST
DISTURBANCE WILL CONTINUE MOVING TO THE SOUTHEAST THIS EVENING.
WINDS HAVE FINALLY INCREASED AHEAD OF THE FRONT OVER PORTIONS OF
CENTRAL AND SOUTHERN NEW MEXICO. THE FRONT WILL REACH THE CENTRAL
MOUNTAIN CHAIN TONIGHT WITH WINDS DIMINISHING AFTER SUNSET. SOME
RAIN SHOWERS AHEAD OF THE FRONT WILL QUICKLY CHANGE OVER TO SNOW
AFTER THE FRONTAL PASSAGE. MEANWHILE...A BACKDOOR COLD FRONT
CURRENTLY OVER THE FAR NE WILL PUSH FARTHER SOUTH TONIGHT AND USHER
IN COOLER TEMPS AND SNOW SHOWERS. AS A RESULT...SNOWFALL
ACCUMULATION WILL CONTINUE ACROSS THE MOUNTAINS AND ADJACENT
HIGHLANDS. OVERNIGHT LOWS WILL GENERALLY BE 5 TO 20 DEGREES BELOW
NORMAL BEHIND THE BACKDOOR COLD FRONT AND A FEW DEGREES BELOW NORMAL
BEHIND THE PACIFIC COLD FRONT. THIS WILL RESULT IN BETTER OVERNIGHT
RH RECOVERIES AREA WIDE.
COOLER AIR WILL CONTINUE SPILLING INTO THE STATE WITH THE SECOND
DISTURBANCE THURSDAY. AS EACH FRONT ADVANCES FARTHER SOUTH DURING
THE DAY...THE FOCUS FOR SNOW ACCUMULATION WILL SHIFT TO AREAS ALONG
AND EAST OF THE CENTRAL MOUNTAIN CHAIN. DESPITE THE COOLER
AIR...DECENT WINDS AND MIXING HEIGHTS WILL ALLOW VENT RATES TO
REMAIN GOOD TO EXCELLENT ACROSS MUCH OF WESTERN AND CENTRAL NM.
HOWEVER...VENT RATES WILL PLUMMET AND BECOME POOR BEHIND THE
BACKDOOR COLD FRONT EAST OF THE CENTRAL MOUNTAIN CHAIN THURSDAY.
DAYTIME HIGH TEMPERATURES WILL BE 10 TO 20 DEGREES COOLER FOR MUCH
OF THE STATE...THOUGH 25 TO 40 DEGREES COOLER ACROSS THE EASTERN
PLAINS. OVERNIGHT RH VALUES WILL CONTINUE TRENDING UP AND BE GOOD TO
EXCELLENT MOST LOCATIONS.
THE SECOND DISTURBANCE WILL EXIT LATE FRIDAY...WITH LIGHT SNOW
ACCUMULATION CONTINUING ACROSS THE EASTERN PLAINS DUE TO PERSISTENT
EASTERLY UP SLOPE FLOW. WARMING WILL BE MINIMAL AS TEMPERATURES REMAIN 10
TO 30 DEGREES BELOW NORMAL ACROSS THE STATE. LIGHTER WINDS AND
GENERALLY LOWER MIXING HEIGHTS WILL CAUSE FAIR TO POOR VENT RATES
FOR MUCH OF THE STATE FRIDAY.
SOUTHWEST FLOW WILL RESTRENGTHEN SATURDAY AS THE THIRD DISTURBANCE
BEGINS TO SHIFT EASTWARD OUT OF THE GREAT BASIN. THIS WILL BRING
INCREASED CHANCES FOR SNOWFALL ACROSS WESTERN AND NORTHERN NM FOR
LATE SATURDAY THROUGH SUNDAY. SHOWERS WILL BEGIN LATE SATURDAY ACROSS THE
FAR NORTHWEST AND SHIFT EAST THROUGH THE EVENT. AS THE THIRD
DISTURBANCE EXITS LATE MONDAY...THE FOURTH DISTURBANCE WILL PUSH
SOUTH FROM THE CENTRAL ROCKIES...CAUSING SNOW SHOWERS TO LINGER
ACROSS THE EASTERN PLAINS INTO MONDAY MORNING. LITTLE CHANGE IS
EXPECTED TO DAYTIME HIGHS THROUGH THIS PERIOD AS A PACIFIC COLD
FRONT WILL REINFORCE THE COLD AIR SUNDAY. A COLD FRONT WITH THE
FOURTH DISTURBANCE WILL KEEP COLD AIR ENTRENCHED WITH POOR VENT
RATES LIKELY TUESDAY.
24/44
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 11 PM MST THURSDAY FOR THE FOLLOWING
ZONES...NMZ510-512>516-521>524-528>534-537-539.
WINTER WEATHER ADVISORY UNTIL 11 PM MST THURSDAY FOR THE FOLLOWING
ZONES...NMZ501>509-511-517>520-525>527-535-536-538.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
907 PM MST WED DEC 4 2013
.UPDATE...
...ESTANCIA VALLEY AND EAST MOUNTAIN COMMUNITIES IN THE CROSSHAIRS
FOR HEAVY SNOW LATE TONIGHT THRU THURSDAY...
HAVE MADE SOME DETAILED CHANGES TO THE FORECAST GRIDS TO NARROW IN
ON EXPECTED AREA OF MOST SIGNIFICANT WINTER WX IMPACTS THRU THURSDAY
NIGHT. THE GREATEST CHALLENGE HAS BEEN WHERE A MESOSCALE BAND OF SNOW
SETS UP OVER CENTRAL NM THEN EXPANDS INTO A BROADER AREA OF SNOWFALL
ACROSS THE EASTERN PLAINS. THE LATEST 00Z NAM GUIDANCE AND RUC13 SHOW
THE BAND NOW FARTHER NORTH MORE LIKE SEVERAL ITERATIONS OF THE GFS/
CANADIAN AND ECMWF. GIVEN THIS NEW INFO AND A FOCUSED ATTEMPT AT QPF
WITH VERY SNOW RATIOS WE WILL EXPAND THE WARNING TO INCLUDE MUCH OF
THE EAST CENTRAL AND NE PLAINS...AS WELL AS ADD THE LOWER RIO GRANDE
VALLEY TO THE ADVISORY. COULD BE VERY INTERESTING FOR THE ESTANCIA
VALLEY AND EAST MTN COMMUNITIES WHERE THE DENDRITIC SNOW GROWTH
LAYER IS SPOT ON WITH THE BEST LIFT AND QPF...AND WITH HIGH SNOW
RATIOS WE MAY SEE SNOW RATES NEAR 1 OR EVEN 2 INCHES PER HOUR FOR A
FEW HOURS THURSDAY MORNING. AREAS OF NORTHWEST NM MAY BE DONE WITH
THIS EVENT HOWEVER WILL GIVE THE MID SHIFT ANOTHER SHOT TO LOOK AT
IT BEFORE DROPPING ANY HIGHLIGHTS.
GUYER
&&
.PREV DISCUSSION...714 PM MST WED DEC 4 2013...
.AVIATION...
00Z TAF CYCLE
WIND IS BECOMING LESS OF AN AVIATION HAZARD AS SPEEDS LOWER. THE
MAIN COLD FRONT TO WATCH THROUGH THE OVERNIGHT HOURS WILL BE FOUND
ACROSS THE EASTERN PLAINS WHERE GUSTS COULD RANGE BETWEEN 25 TO 30
KT. THE MAIN HAZARD WILL BE FOUND WITH THE BAND OF SNOW THAT IS
CURRENTLY IMPACTING WESTERN AND NORTHERN AREAS. LATEST MODELS SHOW
THIS BAND REMAINING MORE CONSOLIDATED AS IT SLOWLY PROGRESSES
EASTWARD. THERE IS A BETTER CHANCE AT SOME SNOWFALL AT AEG/SAF AND
ABQ THAN PREVIOUSLY THOUGHT. THE BEST TIME FOR THESE SITES TO
EXPERIENCE SNOWFALL AND REDUCED CIGS/VIS WILL BE 8Z TO 14Z. AS
MODELS CONTINUE TO COME IN LOOK FOR THIS CHANGE IN UPDATED
TERMINAL FORECASTS. MVFR AND SOME IFR AND EVEN LOCALIZED LIFR
CONDITIONS WILL BE ASSOCIATED WITH THIS SNOW BAND. AS THURS
PROGRESSES THE SNOW BAND WILL INCREASE IN AREAL COVERAGE AND
INTENSITY ACROSS PORTIONS OF THE EASTERN PLAINS. LVS/TCC AND EVEN
ROW SHOULD BE IMPACTED.
50
.PREV DISCUSSION...249 PM MST WED DEC 4 2013...
CURRENTLY...HIGH AMPLITUDE TROUGH FROM CENTRAL SASKATCHEWAN SOUTH
AND WEST TO SOUTHERN CALIFORNIA SWEEPING TOWARD NEW MEXICO...AS
SURFACE LOW DEEPENS OVER NORTHERN NEW MEXICO NEAR THE COLORADO
BORDER. ASSOCIATED COLD FRONT FESTOONED ACROSS THE NORTHERN
TIER...WITH SOUTHBOUND INCURSIONS OVER THE NORTHWEST PLATEAU AND
NORTHEAST PLAINS. SNOW STARTED SO FAR AT FARMINGTON AND
GALLUP...WITH WIDESPREAD SNOW ON TAP ACROSS MUCH OF THE FORECAST
AREA OVER THE NEXT 24 HOURS. WIND SPEEDS HAVE PEGGED WELL ABOVE
WARNING CRITERIA NEAR RUIDOSO...CLINES CORNERS...AND LAS
VEGAS...WITH GUSTS IN THE 40S MPH COMMON AND WIDESPREAD ACROSS THE
FORECAST AREA THIS AFTERNOON.
MODELS...IN REASONABLE AGREEMENT IN A STRONGLY FORCED PATTERN
THROUGH MIDWEEK NEXT WEEK. SIGNIFICANT DIFFERENCES IN PATTERN
EVOLUTION EMERGE FROM THURSDAY ONWARD NEXT WEEK. TROUGH STRETCHED
ACROSS THE INTERMOUNTAIN REGION AND MUCH OF THE WESTERN U.S. WILL
DIG TO THE COASTAL WATERS OF NORTHWESTERN MEXICO THROUGH THURSDAY
BEFORE MAKING EASTWARD SWEEP ACROSS NEW MEXICO THROUGH THURSDAY
NIGHT INTO FRIDAY MORNING. NEXT SHORTWAVE AMPLIFYING FROM ARCTIC
CANADA WESTWARD TOT HE PACIFIC NORTHWEST WILL DIG TO SOUTHERN
CALIFORNIA SATURDAY NIGHT AND CROSS OVER NEW MEXICO THROUGH SUNDAY
AND SUNDAY NIGHT. A QUICK TRAILING WAVE AMPLIFYING UPSTREAM FORM
CENTRAL COLORADO TO SOUTHERN ARIZONA MONDAY WILL MOVE ACROSS NEW
MEXICO THROUGH MONDAY NIGHT. BOTH ECMWF AND GFS SOLUTIONS NOW
PAINTING A DEEPER SHORTWAVE LATE TUESDAY OVER THE FOUR
CORNERS...AND DIFFER ON SPEED OF MOVING THIS FEATURE ACROSS NEW
MEXICO. ECMWF HAS THIS ONE OUTTA HERE BY WEDNESDAY NIGHT AS NEXT
WINTRY WAVE AMPLIFIES FROM ARCTIC CANADA TO CENTRAL CALIFORNIA ON
THURSDAY...AND DIGS THIS INTO A DEEP CLOSED LOW OVER SOUTHERN
SONORA IN NORTHERN MEXICO. GFS SOLUTION LACKS THIS DEEP
DRAMA...SHEARING PACIFIC NORTHWEST SHORTWAVES EASTWARD AND KEEPING
THEM CLEAR OF NEW MEXICO...WHICH SITS IN NORTHWEST FLOW THROUGH
THE REMAINDER OF THE WORK WEEK. ECMWF CLOSED LOW IS A NEW FEATURE
NEAR THE END OF THE FORECAST...THUS WILL SEE IF THIS REAPPEARS IN
FUTURE RUNS WITH BETTER CONTINUITY.
OVERNIGHT...COLD FRONT BLASTING SOUTHWARD WILL REACH THE SOUTHERN
TIER OVER THE EAST BY THURSDAY MORNING...WITH SOUTHBOUND PROGRESS
TO INTERSTATE 40 IN THE WEST. EASTERN WINDS WILL BACK OFF TO THE
EAST AND NORTHEAST...AND WESTWARD PUSH OF THE COLD WILL SET THE
STAGE FOR THE EASTERN SNOW EVENT TO COME. SNOW COVERAGE OVERNIGHT
WILL BECOME WIDESPREAD OVER THE NORTHERN HALF OF THE STATE...WITH
SNOW REACHING SOUTH OF INTERSTATE 40 OVER THE CONTINENTAL DIVIDE.
SANGRE DE CRISTO SUMMITS...ESPECIALLY THE SOUTHERN SUMMITS...WILL
BE MOST FAVORED FOR SNOW ACCUMULATION. PORTIONS OF CHAVES AND
ROOSEVELT COUNTIES MAY HAVE SOME FREEZING RAIN MIXED IN FOR AWHILE
AS ICY RAIN CHANGES OVER TO WET SNOW. 20 TO 30 DEGREE OVERNIGHT
TEMPERATURE DROPS TONIGHT COMPARED TO LAST NIGHT...WITH NORTHEAST
PLAINS SPOTS IN THE SINGLE DIGITS AND LOTS OF TEENS AND 20S
ELSEWHERE. WIND SPEEDS WILL RATCHET DOWN OVERNIGHT...BUT EVENING
GUSTS AND DEVELOPING SNOW OVER THE NORTH...AND OVER THE
CONTINENTAL DIVIDE WILL SET UP SOME OVERNIGHT BLOWING AND DRIFTING
OF SNOW. SNOW AMOUNTS COMING IN A LITTLE HIGHER THIS ROUND...AND
ACCOUNTING FOR ENHANCEMENTS ON THE EAST SLOPES OF THE CENTRAL
MOUNTAIN CHAIN...HAVE EXPANDED WINTER STORM WARNING COVERAGE THIS
ROUND TO THE ENTIRE LENGTH OF THE CENTRAL MOUNTAIN CHAIN...AND
PLACED MOST REMAINING ZONES UNDER WINTER WEATHER ADVISORIES OVER
THE NEXT 24 HOURS.
FOR THURSDAY...AXIS OF TROUGH ALOFT DIGGING INTO THE LOWER
COLORADO RIVER VALLEY AND NORTHERN BAJA CALIFORNIA...AS COLD PUSH
OVER THE EAST MAKES INTENSE EFFORT TO PUSH THROUGH THE CENTRAL
MOUNTAIN CHAIN AND OUT OVER THE RIO GRANDE VALLEY THROUGH THURSDAY
EVENING. VIGOROUS UP SLOPE FLOW AGAINST THE CENTRAL MOUNTAIN CHAIN
WILL SHIFT AND INTENSIFY SNOW COVERAGE OVER THE EAST...WITH
HEAVIEST ACCUMULATIONS OVER THE SOUTHERN SANGRE DE CRISTO
SUMMITS...AND PILED UP ON THE EAST SLOPES AND SUMMITS OF THE
MANZANO AND SANDIA MOUNTAINS...AND ON THE SOUTHWEST FACING SLOPES
BORDERING THE SAN FRANCISCO RIVER VALLEY IN CATRON COUNTY.
FREEZING RAIN REMAINS A THREAT IN THE SOUTHEAST...ESPECIALLY OVER
CHAVES AND SOUTHERN ROOSEVELT COUNTY. 30 TO 40 DEGREE TEMPERATURE
DROPS FROM THOSE LOGGED ON WEDNESDAY WILL BE COMMON ACROSS THE
EAST...WITH CENTRAL POINTS DROPPING 15 TO 25 DEGREES...AND EASTERN
SPOTS 8 TO 15 DEGREES BELOW WEDNESDAY TEMPERATURES. CLIMATE
COMPARISONS PUT THESE TEMPERATURES 30 TO 40 DEGREES BELOW EARLY
DECEMBER NORMALS OVER THE EAST...15 TO 25 DEGREES BELOW OVER THE
CENTRAL...AND 10 TO 20 DEGREES BELOW NORMAL OVER THE WEST.
THURSDAY WINDS WILL BE MUCH REDUCED...WITH SOME SOUTHWEST
BREEZINESS CONTINUING OVER THE SOUTH CENTRAL MOUNTAINS AND
CHUPADERA MESA DURING THE AFTERNOON. SNOW TAPERING OFF AND
SHIFTING TO THE SOUTHEAST THURSDAY NIGHT
FOR FRIDAY...BRISK AND BLUSTERY ZONAL FLOW ACROSS NEW MEXICO AS
WESTERN TROUGH MAKES FAST PASS ACROSS THE STATE...LEAVING ARCTIC
AIR MASS UNTOUCHED AS IT DEPARTS. ONLY MODEST TEMPERATURE
RELIEF...MOST OF THIS FOR THE FRIGID EAST...AS SKIES CLEAR AND
SNOW ENDS. COLD PUSH OUT OF THE CENTRAL PLAINS INTO NORTHEAST NEW
MEXICO LATE FRIDAY WILL REDEVELOP SNOW SHOWERS OVER THE
EAST...WITH MODEST ACCUMULATION SHOWING UP MOSTLY OVER THE
NORTHEAST PLAINS THROUGH FRIDAY NIGHT.
FOR SATURDAY...WESTBOUND COLD FRONT SLOSHED UP AGAINST THE CENTRAL
MOUNTAIN CHAIN...WITH AFTERNOON SOUTHWEST BREEZES STRENGTHENING
OVER THE WEST AND SOUTH CENTRAL...AND SOUTHERLY BREEZES WORKING
INTO THE NORTHEAST. ANOTHER DAY OF WIDESPREAD BUT LESS INTENSE
SNOW COVERAGE OVER THE EAST...WITH AMOUNTS AROUND AN
INCH...LOCALLY HIGHER IN OROGRAPHICALLY ENHANCED SPOTS.
TEMPERATURES REMAINING WELL BELOW EARLY DECEMBER NORMALS.
UPSTREAM...AMPLIFYING TROUGH SWEEPING THROUGH THE WESTERN U.S.
WILL DIG TO SOUTHERN CALIFORNIA BY SATURDAY AFTERNOON...AND INTO
SOUTHERN ARIZONA SATURDAY NIGHT.
OUTLOOK...SUNDAY THROUGH TUESDAY...TROUGH WILL BLUSTER AND SWEEP
ACROSS NEW MEXICO THROUGH THE DAY ON SUNDAY FOR CLEARING
SKIES...CONTINUED WELL BELOW NORMAL TEMPERATURES...AND LAST OF THE
SNOW TAPERING OFF OVER THE NORTHWEST ON MONDAY. SOME MODEST
TEMPERATURE MODERATION ON TUESDAY...WITH SPOTS REMAINING 10 TO 20
DEGREES BELOW MID DECEMBER NORMALS.
SHY
.FIRE WEATHER...
MODELS AGREE FAIRLY WELL WITH THE UPCOMING ACTIVE WEATHER PATTERN. A
PERSISTENT UPPER LEVEL LONG WAVE TROUGH WILL CONTINUE ACROSS NM
THROUGH THE NEXT WEEK. FOUR DISTINCT DISTURBANCES WITHIN THAT FLOW
WILL IMPACT THE STATE. THE FIRST DISTURBANCE IS ONGOING AND WILL
EXIT EAST THURSDAY MORNING. THE SECOND DISTURBANCE WILL QUICKLY
FOLLOW THE FIRST...CONTINUING SNOW SHOWERS ACROSS THE AREA THURSDAY
INTO FRIDAY MORNING. FLOW WILL BE IN TRANSITION FRIDAY...SETTING UP
A THIRD DISTURBANCE WILL DIG DEEPER INTO THE GREAT BASIN LATE
SATURDAY AND SWEEP ACROSS NM FROM THE WEST THROUGH SUNDAY NIGHT.
THIS WILL BE THE NEXT BEST PERIOD OF SIGNIFICANT SNOWFALL
ACCUMULATIONS AND WIND. THE FOURTH DISTURBANCE WILL PUSH SOUTHWARD
OUT OF THE CENTRAL ROCKIES MONDAY INTO TUESDAY...BUT BE FAIRLY
MOISTURE STARVED.
A PACIFIC COLD FRONT ACROSS NW NM ASSOCIATED WITH THE FIRST
DISTURBANCE WILL CONTINUE MOVING TO THE SOUTHEAST THIS EVENING.
WINDS HAVE FINALLY INCREASED AHEAD OF THE FRONT OVER PORTIONS OF
CENTRAL AND SOUTHERN NEW MEXICO. THE FRONT WILL REACH THE CENTRAL
MOUNTAIN CHAIN TONIGHT WITH WINDS DIMINISHING AFTER SUNSET. SOME
RAIN SHOWERS AHEAD OF THE FRONT WILL QUICKLY CHANGE OVER TO SNOW
AFTER THE FRONTAL PASSAGE. MEANWHILE...A BACKDOOR COLD FRONT
CURRENTLY OVER THE FAR NE WILL PUSH FARTHER SOUTH TONIGHT AND USHER
IN COOLER TEMPS AND SNOW SHOWERS. AS A RESULT...SNOWFALL
ACCUMULATION WILL CONTINUE ACROSS THE MOUNTAINS AND ADJACENT
HIGHLANDS. OVERNIGHT LOWS WILL GENERALLY BE 5 TO 20 DEGREES BELOW
NORMAL BEHIND THE BACKDOOR COLD FRONT AND A FEW DEGREES BELOW NORMAL
BEHIND THE PACIFIC COLD FRONT. THIS WILL RESULT IN BETTER OVERNIGHT
RH RECOVERIES AREA WIDE.
COOLER AIR WILL CONTINUE SPILLING INTO THE STATE WITH THE SECOND
DISTURBANCE THURSDAY. AS EACH FRONT ADVANCES FARTHER SOUTH DURING
THE DAY...THE FOCUS FOR SNOW ACCUMULATION WILL SHIFT TO AREAS ALONG
AND EAST OF THE CENTRAL MOUNTAIN CHAIN. DESPITE THE COOLER
AIR...DECENT WINDS AND MIXING HEIGHTS WILL ALLOW VENT RATES TO
REMAIN GOOD TO EXCELLENT ACROSS MUCH OF WESTERN AND CENTRAL NM.
HOWEVER...VENT RATES WILL PLUMMET AND BECOME POOR BEHIND THE
BACKDOOR COLD FRONT EAST OF THE CENTRAL MOUNTAIN CHAIN THURSDAY.
DAYTIME HIGH TEMPERATURES WILL BE 10 TO 20 DEGREES COOLER FOR MUCH
OF THE STATE...THOUGH 25 TO 40 DEGREES COOLER ACROSS THE EASTERN
PLAINS. OVERNIGHT RH VALUES WILL CONTINUE TRENDING UP AND BE GOOD TO
EXCELLENT MOST LOCATIONS.
THE SECOND DISTURBANCE WILL EXIT LATE FRIDAY...WITH LIGHT SNOW
ACCUMULATION CONTINUING ACROSS THE EASTERN PLAINS DUE TO PERSISTENT
EASTERLY UP SLOPE FLOW. WARMING WILL BE MINIMAL AS TEMPERATURES REMAIN 10
TO 30 DEGREES BELOW NORMAL ACROSS THE STATE. LIGHTER WINDS AND
GENERALLY LOWER MIXING HEIGHTS WILL CAUSE FAIR TO POOR VENT RATES
FOR MUCH OF THE STATE FRIDAY.
SOUTHWEST FLOW WILL RESTRENGTHEN SATURDAY AS THE THIRD DISTURBANCE
BEGINS TO SHIFT EASTWARD OUT OF THE GREAT BASIN. THIS WILL BRING
INCREASED CHANCES FOR SNOWFALL ACROSS WESTERN AND NORTHERN NM FOR
LATE SATURDAY THROUGH SUNDAY. SHOWERS WILL BEGIN LATE SATURDAY ACROSS THE
FAR NORTHWEST AND SHIFT EAST THROUGH THE EVENT. AS THE THIRD
DISTURBANCE EXITS LATE MONDAY...THE FOURTH DISTURBANCE WILL PUSH
SOUTH FROM THE CENTRAL ROCKIES...CAUSING SNOW SHOWERS TO LINGER
ACROSS THE EASTERN PLAINS INTO MONDAY MORNING. LITTLE CHANGE IS
EXPECTED TO DAYTIME HIGHS THROUGH THIS PERIOD AS A PACIFIC COLD
FRONT WILL REINFORCE THE COLD AIR SUNDAY. A COLD FRONT WITH THE
FOURTH DISTURBANCE WILL KEEP COLD AIR ENTRENCHED WITH POOR VENT
RATES LIKELY TUESDAY.
24/44
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 11 PM MST THURSDAY FOR THE FOLLOWING
ZONES...NMZ510-512>516-521>524-528>534-537-539.
WINTER WEATHER ADVISORY UNTIL 11 PM MST THURSDAY FOR THE FOLLOWING
ZONES...NMZ501>509-511-517>520-525>527-535-536-538.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1152 PM CST WED DEC 4 2013
.AVIATION...
/06Z TAFS/
PRIMARY CONCERN...ONSET OF FREEZING PRECIP.
ARCTIC AIR IS BEGINNING TO SPILL ACROSS THE RED RIVER...AND
PRESSURE RISES UPSTREAM SUGGEST IT WILL CONTINUE TO SURGE SOUTH
OVERNIGHT. MVFR CEILINGS HAVE ALREADY DEVELOPED NEAR THE FRONTAL
INVERSION...AND THESE CEILINGS SHOULD PERSIST.
THE INITIAL BAND OF PRECIPITATION FRIDAY AFTERNOON MAY BE VERY
LIGHT IF NOT ENTIRELY VIRGA. METROPLEX TEMPERATURES MAY REACH
FREEZING BY SUNSET THURSDAY...BUT THE SIGNIFICANT PRECIPITATION
WILL LIKELY WAIT UNTIL LATE THURSDAY EVENING...PERSISTING THROUGH
DAYBREAK FRIDAY MORNING.
WACO...
GROUND FOG WILL QUICKLY DISSIPATE AS NORTH WINDS AND DRY ADVECTION
INCREASE. THE ONSET OF POTENTIALLY FREEZING PRECIPITATION IN
CENTRAL TEXAS WILL LIKELY BE AFTER MIDNIGHT THURSDAY NIGHT. AS A
RESULT...IT IS NOT INCLUDED IN THE 06Z WACO TAF.
25
&&
.UPDATE...
THE EVENING BALLOON DATA HAS BEEN ANALYZED AND AT 850MB IT
INDICATES VERY COLD AIR ACROSS THE PLAINS IS NOW POURING SOUTH.
DODGE CITY REPORTED -10C AT 850MB AND NORTH PLATTE HAD -17C WITH
NORTH WINDS AT 25 TO 30 KNOTS. SURFACE WINDS AND PRESSURES WERE
NOW RISING TO OUR NORTHWEST...IN RESPONSE TO THE VERY STRONG COLD
ADVECTION OCCURRING ABOVE THE SURFACE. TEMPERATURES AT 850MB
ACROSS THE PLAINS GIVE A BETTER INDICATION OF WHAT OUR SURFACE
TEMPERATURES WILL BE THAN THE CURRENT SURFACE TEMPERATURES THERE
DO. THIS IS BECAUSE THE AIR BEHIND A COLD FRONT UNDERGOES GRADUAL
SUBSIDENCE BEFORE IT REACHES THE SURFACE AT A GIVEN LOCATION.
850MB IS A GREAT LEVEL TO ANALYZE ACROSS KANSAS AND NEBRASKA FOR
AN APPROXIMATION OF WHAT OUR SURFACE TEMPS WILL BE HERE. ASSUMING
ONLY ADIABATIC COMPRESSIONAL WARMING TAKES PLACE .../I.E. NO
SUNSHINE/RADIATIVE/LATENT HEAT CHANGES OCCUR/... THE -10C
EXTRAPOLATES TO SURFACE TEMPS IN THE MID 30S F AND THE -17C TO MID
20S F. THIS AIR WILL ARRIVE INTO OUR AREA THURSDAY AND THURSDAY
NIGHT. ALSO OF NOTE...THE 6-12 HOUR OLD FORECASTS FROM THE
GFS/SREF/NAM WERE 2-4 DEG C TOO WARM AT 850MB ACROSS THE PLAINS.
ALL OF THIS RAISES OUR CONFIDENCE THAT MOST OF THE MODELS CONTINUE
TO UNDERESTIMATE THE SPEED OF THIS COLD AIR AND THAT THE COLDER
TEMPS ARE LIKELY TO ARRIVE EARLIER.
THE RAP HAS SO FAR DONE AN EXCELLENT JOB WITH THIS FRONT AND IT IS
FORECASTING THE FRONT TO CLEAR THE SOUTHERN CWA BY SUNRISE. AS A
RESULT HAVE LOWERED TEMPERATURES SIGNIFICANTLY ACROSS THE SOUTHERN
ZONES FOR LOWS TONIGHT AND HIGHS TOMORROW. THE RAP IS ALSO
FORECASTING THE FREEZING LINE TO REACH THE I-20 CORRIDOR BY MIDDAY
TOMORROW. MEANWHILE A BAND OF PRECIPITATION WILL DEVELOP AND
STREAM ACROSS THE NORTHWESTERN AND NORTHERN ZONES. MOST OF THIS
PRECIP WILL ORIGINATE ABOVE 700MB OR ABOUT 10000 FEET WHICH WILL
LIMIT ITS INTENSITY. FURTHERMORE THE AIR BELOW IT WILL BE VERY DRY
AND SOME OF THIS PRECIP WILL BE LOST TO EVAPORATION BEFORE IT CAN
REACH THE SURFACE. NONETHELESS IT IS LIKELY THAT PRECIP WILL REACH
THE GROUND ACROSS THE NORTHWEST AND NORTHERN ZONES AND EVAPORATIVE
COOLING WILL PUSH SURFACE TEMPS INTO THE 20S. WHILE GROUND
SURFACES ARE STILL VERY WARM...TEMPS IN THE 20S AND WINDS OF 15
MPH WILL BE ENOUGH TO COOL ELEVATED SURFACES/BRIDGES BELOW
FREEZING TO START ACCUMULATING ICE BY THE AFTERNOON HOURS. THE
WINTER STORM WARNING BEGINS AT NOON IN THE AREA ALONG AND NORTH OF
A CISCO TO WEATHERFORD TO SHERMAN LINE AND THIS REGION MAY BEGIN
TO SEE IMPACTS BY AFTERNOON.
FARTHER SOUTH ACROSS THE I-20 CORRIDOR...FREEZING TEMPERATURES ARE
POSSIBLE BY AFTERNOON...BUT PRECIPITATION COVERAGE AND INTENSITY
BECOMES A LITTLE MORE QUESTIONABLE. EITHER WAY FEEL THAT IT IS TOO
LOW OF A RISK FOR IMPACTS TO BRING THE WARNING INTO THE AFTERNOON
HOURS...EVEN THOUGH LIGHT FREEZING RAIN MAY BEGIN TO SHOW UP ON
CARS AND TREES BY THE AFTERNOON RUSH.
THE ONLY CHANGES TO THE PREVIOUS FORECAST FOR THURSDAY NIGHT AND
FRIDAY WERE TO INCREASE ICE ACCUMULATION AMOUNTS NORTH OF I-20.
CONFIDENCE CONTINUES TO INCREASE THAT SIGNIFICANT ICE ACCUMULATION
FROM FREEZING RAIN WILL OCCUR AS TEMPERATURES SHOULD DROP INTO THE
MID TO UPPER 20S AS A LARGE AREA OF MODERATE PRECIPITATION MOVES
INTO THE REGION. EVEN DESPITE THE VERY WARM TEMPERATURES ALOFT AND
RAIN DROPS THAT WILL LIKELY BE A FEW DEGREES ABOVE FREEZING WHEN
THEY REACH THE GROUND...STRONG COLD/DRY ADVECTION WILL BE ONGOING
DURING THIS EVENT WHICH SHOULD KEEP TEMPERATURES BELOW FREEZING
AND LIKELY IN 20S ACROSS THE WARNING AREA. WE ARE PARTICULARLY
CONCERNED ABOUT DENTON...COLLIN...COOKE...GRAYSON...AND FANNIN
COUNTIES WHERE THE JUXTAPOSITION OF HIGH AMOUNTS OF FREEZING RAIN
AND TEMPERATURES IN THE MID TO UPPER 20S WILL OCCUR. SIGNIFICANT
ICING OF TREES IN THIS AREA WOULD LEAD TO LIMB BREAKAGE AND POWER
OUTAGES THAT MAY LAST FOR DAYS IN SOME COMMUNITIES. FURTHERMORE
NOT ALL TREES HAVE LOST THEIR LEAVES YET WHICH WILL ADD TO TREE
LIMB STRESS DUE TO THE WEIGHT OF MORE ICE. MORE SLEET IS POSSIBLE
FOR THE NORTHWESTERN ZONES WHICH SHOULD LIMIT ICE ACCUMULATION ON
TREES AND HOPEFULLY MITIGATE DAMAGE TO THE POWER GRID BUT IT IS A
TOUGH CALL. ACROSS THE REMAINDER OF THE WARNING AREA...AND
ESPECIALLY ALONG AND NORTH OF I-20...SIGNIFICANT TRAVEL
DISRUPTIONS WILL OCCUR FROM ICE ON ROADS. ICE MAY LINGER FOR DAYS
AS SKIES STAY CLOUDY AND TEMPERATURES REMAIN BELOW FREEZING.
ANOTHER SHOT AT SLEET AND FREEZING RAIN WILL OCCUR ON SATURDAY
AFTERNOON AND NIGHT.
WILL BE UPDATING THE WINTER STORM WARNING TO INCREASE THE
SEVERITY OF THE WORDING AND IMPACTS ACROSS THE NORTHERN AND
NORTHWESTERN ZONES.
TR.92
&&
.PREV DISCUSSION... /ISSUED 321 PM CST WED DEC 4 2013/
WE/VE UPGRADED AND EXPANDED THE WINTER STORM WATCH TO A WINTER
STORM WARNING NORTHWEST OF A GOLDTHWAITE TO CANTON LINE AND ADDED
A WINTER WEATHER ADVISORY SOUTHEASTWARD TO A TEMPLE TO PALESTINE
LINE.
TODAY/S FRONT HAS REACHED A NORTH OF PARIS TO EASTLAND LINE BY 2
PM AND WILL CONTINUE TO MOVE SOUTH OVERNIGHT. MUCH COLDER AIR IS
SPREADING THROUGH OKLAHOMA AND WILL INVADE NORTH TEXAS LATER TONIGHT
AND CENTRAL TEXAS THURSDAY MORNING AND EARLY AFTERNOON. LIGHT RAIN
SHOULD BEGIN OVERNIGHT DUE TO FRONTAL LIFTING AND ISENTROPIC
UPGLIDE.
THURSDAY THROUGH FRIDAY...TEMPERATURES WILL NOT CHANGE VERY MUCH ON
THURSDAY DUE TO COLD AIR ADVECTION...CLOUDS AND PRECIPITATION.
SOME FREEZING RAIN WILL BE POSSIBLE OVER THE FAR NORTHWEST
COUNTIES BEFORE SUNSET. CONDITIONS WILL CONTINUE TO DETERIORATE AS
FREEZING RAIN BECOMES MORE PREDOMINATE AS THE COLD AIR DEEPENS.
MODERATE TO HEAVY RAINFALL AND FREEZING RAIN IS POSSIBLE THURSDAY
MID EVENING THROUGH EARLY FRIDAY MORNING GENERALLY NORTHWEST OF A
HAMILTON TO DALLAS TO PARIS LINE WITH THE AXIS ALIGNED FROM
COMANCHE TO SHERMAN. ISOLATED THUNDER MAY ALSO OCCUR AFTER
MIDNIGHT. IF THIS RAINFALL MATERIALIZES...THEN A SIGNIFICANT ICE
STORM COULD DEVELOP IF TEMPERATURES CAN FALL INTO THE 20S.
HOWEVER...THIS COULD ALSO BE A CASE WHERE RAIN FALLING THROUGH THE
WARM NOSE ALOFT GAINS ENOUGH HEAT TO PREVENT SURFACE TEMPERATURES
FROM FALLING MUCH BELOW FREEZING. THUS...THE TEMPORAL AND SPATIAL
CHARACTERISTICS OF THE TRANSITION TO ALL FREEZING RAIN REMAINS
HARD TO DETERMINE. IT COULD REMAIN WEST OF THE METROPLEX THROUGH
FRIDAY MIDDAY OR IT COULD MIGRATE EAST ACROSS THE METROPLEX BEFORE
DAYBREAK AND DURING THE MORNING HOURS. BY ANY TOKEN...TEMPERATURES
ABOVE HOUSE TOPS WILL BE COLD ENOUGH FOR ICE TO ACCUMULATE ON
ELEVATED SURFACES AND STRUCTURES...AND THIS COULD BRING DOWN POWER
LINES AND TREE LIMBS...AND MAKE BRIDGES AND OVERPASSES ICY.
AS THE FREEZING AIR CONTINUES TO DEEPEN ON FRIDAY...SLEET WILL
BECOME MORE LIKELY...ESPECIALLY OVER THE NORTHERN HALF OF THE CWA.
SLEET AMOUNTS COULD TOTAL UP TO ONE HALF INCH. THE WINTRY
PRECIPITATION SHOULD END FOR FRIDAY NIGHT...BUT IT WILL RETURN
SATURDAY THROUGH SUNDAY AS AN UPPER DISTURBANCE MOVES ACROSS THE
REGION.
WITH COLD TEMPERATURES REMAINING ACROSS THE REGION THROUGH MUCH OF
THIS FORECAST...ICE ACCUMULATIONS WILL LIKELY HANG AROUND THROUGH
THE WEEKEND AND IN SOME AREAS THROUGH TUESDAY.
ONCE THE ARCTIC AIR SETTLES OVER THE REGION...HIGHS ARE NOT
EXPECTED TO WARM ABOVE 40 DEGREES UNTIL THE MIDDLE OF NEXT WEEK.
LOWS WILL VARY DAY TO DAY...BUT WILL LIKELY WILL BE IN THE TEENS
AND 20S THIS WEEKEND THROUGH TUESDAY MORNING. SOME RED RIVER
LOCATIONS MAY SEE SINGLE DIGITS ON TUESDAY MORNING. 75
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 36 37 26 29 19 / 20 50 90 50 10
WACO, TX 40 43 29 32 21 / 20 30 80 50 10
PARIS, TX 35 36 27 29 17 / 20 50 90 60 10
DENTON, TX 35 35 24 26 17 / 20 60 90 50 10
MCKINNEY, TX 35 36 25 27 18 / 20 50 90 50 10
DALLAS, TX 37 37 26 29 20 / 20 50 90 50 10
TERRELL, TX 37 38 27 29 20 / 20 40 90 50 10
CORSICANA, TX 40 41 29 33 22 / 20 30 80 60 10
TEMPLE, TX 42 44 30 32 22 / 20 30 80 60 10
MINERAL WELLS, TX 35 35 23 25 17 / 20 60 70 40 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THURSDAY TO 6 PM CST FRIDAY FOR
TXZ094-095-104>107-118>123-130>134-141>145.
WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM CST FRIDAY FOR TXZ135-
146>148-156>161.
WINTER STORM WARNING FROM NOON THURSDAY TO 6 PM CST FRIDAY FOR
TXZ091>093-100>103-115>117-129.
&&
$$
25/92
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1129 PM CST WED DEC 4 2013
.AVIATION...
NO SIGNIFICANT CHANGES TO ONGOING TAFS. SOUTH TO SOUTHEASTERLY
FLOW WILL CONTINUE OVERNIGHT BRINGING WARM...MOIST AIR INTO THE
REGION. BEGINNING TO SEE VIS DROPPING IN FOG. EXPECT THIS TREND TO
CONTINUE AND ALSO LOOKING FOR CIGS TO DROP. EXPECTING FLYING
CONDITIONS TO DROP TO IFR BY AROUND 07Z AND TO VLIFR A COUPLE OF
HOURS LATER. SHOULD SEE SOME IMPROVEMENT NEAR SUNRISE WHEN A COLD
FRONT WILL MOVE THROUGH AND TURN THE WINDS AROUND TO THE NORTH.
THEN CIGS WILL RISE TO MVFR LATE MORNING THURSDAY. WINDS WILL BE
OUT OF THE NORTH AT 15 WITH GUSTS TO 25 KTS DURING THE DAY
THURSDAY. EXPECT SLIGHT CHANCE FOR RAIN AFTER 00Z WHICH SHOULD BE
LIGHT AND HAVE LITTLE IMPACT ON VIS. BETTER CHANCE FOR RAIN AFTER
06Z AT 30 HOUR AIRPORTS.
&&
.PREV DISCUSSION... /ISSUED 1005 PM CST WED DEC 4 2013/
UPDATE...
WE HAVE UPDATED THE FORECAST TO INCLUDE A DENSE FOG ADVISORY FOR
AREAS GENERALLY ALONG AND EAST OF THE I-35 CORRIDOR.
DISCUSSION...
DEW POINTS IN THE UPPER 50S TO UPPER 60S ALONG WITH LIGHT WINDS
HAVE ALLOWED FOG TO DEVELOP LATE THIS EVENING. WITH CONTINUED
COOLING AND LIGHT WINDS...SUSPECT WE COULD SEE SOME AREAS OF DENSE
FOG AFTER MIDNIGHT ACROSS PORTIONS OF SOUTH CENTRAL TEXAS. THE
LATEST HI-RES RUC CONTINUES TO SUPPORT THE ABOVE AND WE HAVE OPTED
TO ISSUE A DENSE FOG ADVISORY FOR COUNTIES ALONG AND EAST OF A
CARRIZO SPRINGS TO UVALDE TO SAN ANTONIO TO AUSTIN LINE.
VISIBILITIES OF ONE QUARTER MILE OR LESS POSSIBLE IN THE ADVISORY
AREA.
THE LATEST FEW RUNS OF THE HI-RES RUC ALSO CONTINUES TO SHOW A
QUICKER FRONTAL PASSAGE EARLY TOMORROW MORNING. WE HAVE ADJUSTED
THE FORECAST TO ACCOUNT FOR A LITTLE EARLIER ARRIVAL OF THE COLD
FRONT. VISIBILITIES WILL QUICKLY IMPROVE BEHIND THE FRONT.
PREV DISCUSSION... /ISSUED 327 PM CST WED DEC 4 2013/
SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)...
ABOVE NORMAL TEMPERATURES WILL CONTINUE THIS EVENING WITH LOW
CLOUDS AND PATCHY FOG DEVELOPING LATE TONIGHT. THE STRONG ARCTIC
FRONT IS SET TO ENTER THE FORECAST AREA BY AROUND 09Z AND INTO
AUSTIN BY 12Z AND SAT BY 15Z. MODEL RUN-TO-RUN TRENDS SUGGEST A
SLIGHT ACCELERATION OF THE FRONT POSSIBLE. DAYTIME TEMPERATURE
TRENDS CONTINUE DOWNWARD FOR THURSDAY...AND BY LATE EVENING...A FEW
LOCATIONS OF THE NORTHERN HILL COUNTRY MAY BE AT RISK OF
REACHING THE FREEZING MARK. SIMILAR TO THE PREVIOUS ARCTIC
FRONT... LIGHT TO MODERATE RAIN SHOWERS ARE EXPECTED TO OVERRUN
THE ARCTIC AIR AND PRODUCE A THREAT OF FREEZING RAIN...ESPECIALLY
LATE THURSDAY NIGHT. PF AMOUNTS WILL BE MAINLY BELOW 1/10 INCH...
AND SO A WINTER STORM WATCH IS NOT ANTICIPATED AT THIS TIME. A
WINTER WEATHER ADVISORY LEVEL THREAT IS CURRENTLY ANTICIPATED...
WITH WARM GROUND TEMPERATURES EXPECTED TO CONFINE EARLY ICING TO
MAINLY BRIDGES AND OVERPASSES.
LONG TERM (FRIDAY THROUGH WEDNESDAY)...
PRECIPITATION RATES ARE EXPECTED TO DECREASE FRIDAY AS A SHALLOW
SHORTWAVE TROUGH PASSES MAINLY NORTH OF THE AREA. ISENTROPIC LIFT
OVER THE FRONT IS EXPECTED TO CONTINUE THROUGH THE WEEKEND...BUT
WILL HAVE TO OVERCOME CONTINUED DRY AIR REINFORCEMENT IN THE
LOWEST 3000 FT OR MORE. LIGHT RAIN AND SPRINKLES WILL EVENTUALLY
BE REDUCED TO DRIZZLE AT THE SURFACE...SO VERY LITTLE ICING IS
ANTICIPATED...DESPITE SEVERAL HOURS OF OPPORTUNITY OF FREEZING
DRIZZLE AND SLEET SHOWN IN THE FORECAST. PERSISTENT EVAPORATIVE
COOLING FROM THE LIGHT PRECIPITATION PATTERN AND MODEL TRENDS ON
TEMPERATURES SUGGEST THIS AIR MASS WILL BE COLDER THAN THE ONE
PRIOR TO THANKSGIVING. IF ANY SHORTWAVE ACTIVITY IS DETECTED IN
THE BROAD ZONAL FLOW ALOFT...THE HIGHER PRECIPITATION RATES THAT
RESULT WOULD WARRANT A WINTER STORM WATCH OR WARNING TO BE
ISSUED.
BY LATE SUNDAY MORNING...A MORE SIGNIFICANT SHORTWAVES IN
THE FLOW ALOFT IS EXPECTED TO PASS NORTH OF SOUTH CENTRAL TEXAS.
AS IT DOES SO...THERE IS A GOOD CHANCE FOR WAKE SUBSIDENCE TO
CLEAR OUT SKIES AND MODIFY THE TEMPERATURES TO END THE FREEZING
PRECIPITATION POTENTIAL. MODEL TRENDS...ESPECIALLY FROM THE
GFS...SHOW THE BASE OF THE BROADER UPPER TROUGH BECOMING MORE
SHALLOW SUNDAY INTO MONDAY...THUS FURTHER INCREASING THE CHANCE
FOR CLEARING SKIES. NEVERTHELESS...COLD AIR ADVECTION WILL BE
FURTHER REINFORCED ON MONDAY WITH THE COLDEST MORNING LOWS OF THE
SEASON EXPECTED OVER MANY AREAS BY TUESDAY MORNING. A SPLIT FLOW
PATTERN REMAINS IN THE FORECAST FOR THE REST OF NEXT WEEK...
LEADING TO A HIGHER CHANCE FOR CLOUD COVER AND COOLER THAN
NORMAL TEMPERATURES CONTINUING INTO NEXT WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 51 57 33 38 29 / 10 30 70 60 20
AUSTIN BERGSTROM INTL AIRPORT 54 59 34 38 28 / 10 30 70 60 20
NEW BRAUNFELS MUNI AIRPORT 60 62 37 39 29 / 10 30 70 50 30
BURNET MUNI AIRPORT 46 49 31 35 25 / 10 30 70 50 20
DEL RIO INTL AIRPORT 60 68 39 47 33 / - 20 60 20 -
GEORGETOWN MUNI AIRPORT 48 53 31 35 26 / 10 30 70 60 20
HONDO MUNI AIRPORT 60 67 38 40 33 / 10 20 60 30 20
SAN MARCOS MUNI AIRPORT 59 61 36 38 29 / 10 30 70 60 20
LA GRANGE - FAYETTE REGIONAL 65 67 38 39 33 / 10 30 60 70 30
SAN ANTONIO INTL AIRPORT 62 64 36 39 32 / 10 20 70 50 20
STINSON MUNI AIRPORT 63 65 38 41 34 / 10 20 60 50 20
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 6 AM CST THURSDAY FOR THE FOLLOWING
COUNTIES: ATASCOSA...BASTROP...BEXAR...CALDWELL...COMAL...DE WITT...
DIMMIT...FAYETTE...FRIO...GONZALES...GUADALUPE...HAYS...KARNES...
LAVACA...LEE...MEDINA...TRAVIS...UVALDE...WILSON...ZAVALA.
&&
$$
MESOSCALE/AVIATION...05
SYNOPTIC/GRIDS...24
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
1005 PM CST WED DEC 4 2013
.UPDATE...
WE HAVE UPDATED THE FORECAST TO INCLUDE A DENSE FOG ADVISORY FOR
AREAS GENERALLY ALONG AND EAST OF THE I-35 CORRIDOR.
&&
.DISCUSSION...
DEW POINTS IN THE UPPER 50S TO UPPER 60S ALONG WITH LIGHT WINDS
HAVE ALLOWED FOG TO DEVELOP LATE THIS EVENING. WITH CONTINUED
COOLING AND LIGHT WINDS...SUSPECT WE COULD SEE SOME AREAS OF DENSE
FOG AFTER MIDNIGHT ACROSS PORTIONS OF SOUTH CENTRAL TEXAS. THE
LATEST HI-RES RUC CONTINUES TO SUPPORT THE ABOVE AND WE HAVE OPTED
TO ISSUE A DENSE FOG ADVISORY FOR COUNTIES ALONG AND EAST OF A
CARRIZO SPRINGS TO UVALDE TO SAN ANTONIO TO AUSTIN LINE.
VISIBILITIES OF ONE QUARTER MILE OR LESS POSSIBLE IN THE ADVISORY
AREA.
THE LATEST FEW RUNS OF THE HI-RES RUC ALSO CONTINUES TO SHOW A
QUICKER FRONTAL PASSAGE EARLY TOMORROW MORNING. WE HAVE ADJUSTED
THE FORECAST TO ACCOUNT FOR A LITTLE EARLIER ARRIVAL OF THE COLD
FRONT. VISIBILITIES WILL QUICKLY IMPROVE BEHIND THE FRONT.
&&
.PREV DISCUSSION... /ISSUED 539 PM CST WED DEC 4 2013/
AVIATION...
SOUTH TO SOUTHEASTERLY FLOW WILL CONTINUE OVERNIGHT BRINGING
WARM...MOIST AIR INTO THE REGION. EXPECTING LOW CIGS TO FORM LATER
TONIGHT IN THE AUSTIN AND SAN ANTONIO AREAS. ALSO EXPECTING VIS TO
BE REDUCED BY FOG. EXPECTING FLYING CONDITIONS TO DROP TO IFR BY
AROUND 05Z AND TO VLIFR A COUPLE OF HOURS LATER. SHOULD SEE SOME
IMPROVEMENT NEAR SUNRISE WHEN A COLD FRONT WILL MOVE THROUGH AND
TURN THE WINDS AROUND TO THE NORTH. THEN CIGS WILL RISE TO MVFR
LATE MORNING THURSDAY. WINDS WILL BE OUT OF THE NORTH AT 15 WITH
GUSTS TO 25 KTS DURING THE DAY THURSDAY. THERE IS SOME CHANCE FOR
RAIN SHOWERS THURSDAY BEHIND THE FRONT...BUT PROBABILITY IS TOO
LOW TO INCLUDED IN THE TAFS AT THIS TIME.
PREV DISCUSSION... /ISSUED 327 PM CST WED DEC 4 2013/
SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)...
ABOVE NORMAL TEMPERATURES WILL CONTINUE THIS EVENING WITH LOW
CLOUDS AND PATCHY FOG DEVELOPING LATE TONIGHT. THE STRONG ARCTIC
FRONT IS SET TO ENTER THE FORECAST AREA BY AROUND 09Z AND INTO
AUSTIN BY 12Z AND SAT BY 15Z. MODEL RUN-TO-RUN TRENDS SUGGEST A
SLIGHT ACCELERATION OF THE FRONT POSSIBLE. DAYTIME TEMPERATURE
TRENDS CONTINUE DOWNWARD FOR THURSDAY...AND BY LATE EVENING...A FEW
LOCATIONS OF THE NORTHERN HILL COUNTRY MAY BE AT RISK OF
REACHING THE FREEZING MARK. SIMILAR TO THE PREVIOUS ARCTIC
FRONT... LIGHT TO MODERATE RAIN SHOWERS ARE EXPECTED TO OVERRUN
THE ARCTIC AIR AND PRODUCE A THREAT OF FREEZING RAIN...ESPECIALLY
LATE THURSDAY NIGHT. PF AMOUNTS WILL BE MAINLY BELOW 1/10 INCH...
AND SO A WINTER STORM WATCH IS NOT ANTICIPATED AT THIS TIME. A
WINTER WEATHER ADVISORY LEVEL THREAT IS CURRENTLY ANTICIPATED...
WITH WARM GROUND TEMPERATURES EXPECTED TO CONFINE EARLY ICING TO
MAINLY BRIDGES AND OVERPASSES.
LONG TERM (FRIDAY THROUGH WEDNESDAY)...
PRECIPITATION RATES ARE EXPECTED TO DECREASE FRIDAY AS A SHALLOW
SHORTWAVE TROUGH PASSES MAINLY NORTH OF THE AREA. ISENTROPIC LIFT
OVER THE FRONT IS EXPECTED TO CONTINUE THROUGH THE WEEKEND...BUT
WILL HAVE TO OVERCOME CONTINUED DRY AIR REINFORCEMENT IN THE
LOWEST 3000 FT OR MORE. LIGHT RAIN AND SPRINKLES WILL EVENTUALLY
BE REDUCED TO DRIZZLE AT THE SURFACE...SO VERY LITTLE ICING IS
ANTICIPATED...DESPITE SEVERAL HOURS OF OPPORTUNITY OF FREEZING
DRIZZLE AND SLEET SHOWN IN THE FORECAST. PERSISTENT EVAPORATIVE
COOLING FROM THE LIGHT PRECIPITATION PATTERN AND MODEL TRENDS ON
TEMPERATURES SUGGEST THIS AIR MASS WILL BE COLDER THAN THE ONE
PRIOR TO THANKSGIVING. IF ANY SHORTWAVE ACTIVITY IS DETECTED IN
THE BROAD ZONAL FLOW ALOFT...THE HIGHER PRECIPITATION RATES THAT
RESULT WOULD WARRANT A WINTER STORM WATCH OR WARNING TO BE
ISSUED.
BY LATE SUNDAY MORNING...A MORE SIGNIFICANT SHORTWAVES IN
THE FLOW ALOFT IS EXPECTED TO PASS NORTH OF SOUTH CENTRAL TEXAS.
AS IT DOES SO...THERE IS A GOOD CHANCE FOR WAKE SUBSIDENCE TO
CLEAR OUT SKIES AND MODIFY THE TEMPERATURES TO END THE FREEZING
PRECIPITATION POTENTIAL. MODEL TRENDS...ESPECIALLY FROM THE
GFS...SHOW THE BASE OF THE BROADER UPPER TROUGH BECOMING MORE
SHALLOW SUNDAY INTO MONDAY...THUS FURTHER INCREASING THE CHANCE
FOR CLEARING SKIES. NEVERTHELESS...COLD AIR ADVECTION WILL BE
FURTHER REINFORCED ON MONDAY WITH THE COLDEST MORNING LOWS OF THE
SEASON EXPECTED OVER MANY AREAS BY TUESDAY MORNING. A SPLIT FLOW
PATTERN REMAINS IN THE FORECAST FOR THE REST OF NEXT WEEK...
LEADING TO A HIGHER CHANCE FOR CLOUD COVER AND COOLER THAN
NORMAL TEMPERATURES CONTINUING INTO NEXT WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 51 57 33 38 29 / 10 30 70 60 20
AUSTIN BERGSTROM INTL AIRPORT 54 59 34 38 28 / 10 30 70 60 20
NEW BRAUNFELS MUNI AIRPORT 60 62 37 39 29 / 10 30 70 50 30
BURNET MUNI AIRPORT 46 49 31 35 25 / 10 30 70 50 20
DEL RIO INTL AIRPORT 60 68 39 47 33 / - 20 60 20 -
GEORGETOWN MUNI AIRPORT 48 53 31 35 26 / 10 30 70 60 20
HONDO MUNI AIRPORT 60 67 38 40 33 / 10 20 60 30 20
SAN MARCOS MUNI AIRPORT 59 61 36 38 29 / 10 30 70 60 20
LA GRANGE - FAYETTE REGIONAL 65 67 38 39 33 / 10 30 60 70 30
SAN ANTONIO INTL AIRPORT 62 64 36 39 32 / 10 20 70 50 20
STINSON MUNI AIRPORT 63 65 38 41 34 / 10 20 60 50 20
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 6 AM CST THURSDAY FOR THE FOLLOWING
COUNTIES: ATASCOSA...BASTROP...BEXAR...CALDWELL...COMAL...DE WITT...
DIMMIT...FAYETTE...FRIO...GONZALES...GUADALUPE...HAYS...KARNES...
LAVACA...LEE...MEDINA...TRAVIS...UVALDE...WILSON...ZAVALA.
&&
$$
MESOSCALE/AVIATION...05
SYNOPTIC/GRIDS...24
PUBLIC SERVICE/DATA COLLECTION...33
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1111 PM CST WED DEC 4 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY MORNING)
ISSUED AT 316 PM CST WED DEC 4 2013
MAIN FORECAST CONCERN IS ON DEPARTING WEATHER SYSTEM...FOLLOWED
BY THE ARCTIC AIR MASS SURGE.
AS OF 3 PM WEDNESDAY...SURFACE ANALYSIS SHOWED 998 MB LOW
PRESSURE CENTERED NEAR DECORAH IOWA...WITH A WARM FRONT SITUATED
FROM NEAR PRAIRIE DU CHIEN WISCONSIN EASTWARD INTO SOUTHERN
WISCONSIN. FINALLY...THE LEADING EDGE OF THE COLD AIR WAS ALONG
THE I-35 CORRIDOR IN MINNESOTA AND IOWA.
THE SURFACE LOW IS EXPECTED TO LIFT NORTHEAST TO NORTHERN WISCONSIN
LATER THIS EVENING...THEN OVER LAKE SUPERIOR BY MIDNIGHT. THE COLD
FRONT SHOULD MAKE A CLEAN SWEEP ACROSS THE ENTIRE FORECAST AREA BY
03Z. THE SURGE OF WARMER AIR AHEAD OF THE SURFACE LOW IS KEEPING
WINTER PRECIPITATION THREAT LOW AT THIS TIME BUT STILL PLENTY OF
1/4 SM VISIBILITIES OR LOWER. LOCATIONS WILL HAVE TO WAIT FOR THE
COLD FRONTAL PASSAGE FOR IMPROVED VISIBILITIES...AND AREAS EAST OF
THE MISSISSIPPI RIVER AND NORTH OF I-90 IN WISCONSIN WILL LIKELY
HANG ONTO THE REDUCED VISIBILITIES THE LONGEST.
AHEAD OF THE COLD FRONT...STRONG LOW LEVEL LIFT AND SATURATION
COMBINED WITH VERY LITTLE ICE SATURATION ALOFT WILL LIKELY LEAD TO
DRIZZLE. HIGH RES MODELS SUCH AS THE HRRR CAPTURE THIS FAIRLY WELL.
BEHIND THE COLD FRONT...TEMPERATURES QUICKLY FALL INTO THE UPPER 20S
TO NEAR 30 DEGREES. ALTHOUGH MOISTURE IS TRAPPED IN THE LOW-LEVEL
INVERSION...THE LIFT BEGINS TO DROP OFF BUT THERE IS LIKELY TO BE
A PERIOD OF FREEZING DRIZZLE. AS EVEN COLDER AIR WORKS IN
ALOFT...SATURATION IN THE ICE GROWTH LAYER RETURNS SO PRECIPITATION
COULD END AS SNOW FLURRIES OR SNOW SHOWERS...ESPECIALLY ACROSS
CENTRAL MINNESOTA...INTO NORTH CENTRAL WISCONSIN BEFORE TAPERING
OFF ALTOGETHER TOWARD MIDNIGHT. AS SUCH...THE WINTER WEATHER
ADVISORY FOR TAYLOR/CLARK COUNTIES WILL REMAIN IN PLACE BUT LIKELY
COULD BE ENDED TOWARD MIDNIGHT.
FOR THURSDAY MORNING...GOOD CONSENSUS THAT PLENTY OF MOISTURE
REMAINS TRAPPED IN THE LOW LEVELS...MAINLY CENTERED AROUND 900 MB.
LIFT IS VERY WEAK BUT THE SURGE OF ARCTIC AIR SHOULD PUT THE DGZ
CLOSER TO 900 MB. THIS SUPPORTS VERY LIGHT BUT OCCASIONAL TO PERIODS
OF SNOW FLURRIES ACROSS NORTH CENTRAL WISCONSIN...BECOMING MORE
SCATTERED CLOSER TO ROCHESTER AND LA CROSSE.
.LONG TERM...(THURSDAY THROUGH WEDNESDAY)
ISSUED AT 316 PM CST WED DEC 4 2013
HIGHLIGHTS IN THE LONG TERM ARE ARCTIC AIR MASS SURGES AND
ACCUMULATING SNOWFALL POTENTIAL SUNDAY NIGHT.
THE CURRENT STORM SYSTEM DEEPENS AND QUICKLY DEPARTS NORTHEAST OF
THE GREAT LAKES REGION THURSDAY WHILE THE WESTERN TWO-THIRDS OF THE
CONUS REMAINS UNDER THE INFLUENCE OF THE UPPER LEVEL LONGWAVE
TROUGH. AS WELL ADVERTISED PREVIOUSLY...THE ARCTIC AIR SURGE
BEGINS IN EARNEST THURSDAY AND FRIDAY AS NOTED BY 850 MB
TEMPERATURES FALLING FROM AN AVERAGE OF -8C 12Z THURSDAY...TO -17C
BY 18Z FRIDAY. 850 MB STANDARDIZED ANOMALIES FALL TO 2 TO 2.5
DEGREES BELOW NORMAL...WHICH IS NOT RECORD COLD TERRITORY BUT
CERTAINLY UNSEASONABLE FOR THIS TIME OF YEAR. THE FRESH SNOWPACK
ACROSS CENTRAL MINNESOTA INTO NORTH CENTRAL WISCONSIN IS LIKELY TO
KEEP TEMPERATURES ON THE LOWER SIDE OF GUIDANCE AS WELL. LATEST
SNOW DEPTH READINGS SHOW ANYWHERE FROM A FEW INCHES FROM SOUTH CENTRAL
MINNESOTA...TO ALMOST 10 INCHES IN TAYLOR COUNTY. FORECAST
TEMPERATURES WERE NUDGED DOWN SLIGHTLY BY A FEW DEGREES FROM
PREVIOUS FORECAST.
A NOTICEABLY COLDER DAY ON TAP THURSDAY...WITH HIGHS ONLY IN THE
TEENS TO LOWER 20S. STIFF NORTHWEST WINDS WILL MAKE FOR WIND CHILL
READINGS IN THE SINGLE DIGITS ABOVE ZERO AT TIMES FOR MUCH OF THE
DAY. EVEN COLDER TEMPERATURES ARE EXPECTED FRIDAY AND
SATURDAY...MAINLY SINGLE DIGITS TO TEENS. FOR REFERENCE...NORMAL
HIGHS FOR THIS TIME OF YEAR ARE IN THE UPPER 20S TO LOWER 30S AND
LOWS IN THE TEENS. AS FAR AS LOW TEMPERATURES GO...SEVERAL
MORNINGS OF SUB ZERO READINGS EXPECTED FOR PARTS OF SOUTHEAST
MINNESOTA INTO NORTH CENTRAL WISCONSIN WHILE THE REST OF THE AREA
SHOULD FALL INTO THE SINGLE DIGITS ABOVE ZERO.
A WIND CHILL ADVISORY IS LIKELY NEEDED FOR PARTS OF THE AREA FRIDAY
NIGHT INTO SATURDAY AS THE SURFACE HIGH PRESSURE DROPS SOUTH TO OUR
WEST. THIS KEEPS A 10 TO 15 MPH WIND DURING THE OVERNIGHT ACROSS THE
AREA...RESULTING IN WIND CHILL READINGS IN THE 15 TO 25 DEGREE BELOW
ZERO RANGE NORTH OF INTERSTATE 90.
FOR THE UPCOMING WEEKEND...SATURDAY LOOKS TO BE ANOTHER UNSEASONABLY
COLD BUT DRY DAY WITH HIGHS IN THE SINGLE DIGITS TO TEENS.
HOWEVER...ON SUNDAY WITH THE MAIN UPPER LEVEL TROUGH REMAINING IN
PLACE ACROSS THE WESTERN CONUS...ANOTHER PIECE OF UPPER LEVEL ENERGY
DIGS INTO THE SOUTHWEST U.S. WHICH IS EXPECTED TO ALLOW A SURFACE
LOW TO DEVELOP IN THE LEE SIDE OF THE ROCKIES. PREVIOUS MODEL
CYCLES...AND THE 04.12Z GUIDANCE CONTINUE TO SHOW VERY GOOD
AGREEMENT THIS FAR OUT WHICH BOOSTS CONFIDENCE DURING THIS PERIOD.
THE SURFACE LOW IS EXPECTED TO BE NEAR CENTRAL OKLAHOMA 18Z
SUNDAY...THEN MOVE TOWARD CENTRAL ILLINOIS BY 06Z MONDAY. ON THE
NORTHWEST SIDE...AN INVERTED SURFACE TROUGH COUPLED WITH THE UPPER
LEVEL ENERGY IS LIKELY TO PROVIDE PLENTY OF LIFT TO SUPPORT SNOW
ACROSS MUCH OF THE FORECAST AREA. PRECIPITATION CHANCES WERE BOOSTED
TO LIKELY ACROSS NORTHEAST IOWA INTO WESTERN AND SOUTHERN
WISCONSIN...AND INTO THE 40 TO 50 PERCENT RANGE ELSEWHERE. STILL TOO
EARLY TO SPECULATE ON SNOWFALL AMOUNTS...BUT IMPACTFUL WEATHER IS
LOOKING LIKELY SUNDAY AFTERNOON INTO MONDAY MORNING FOR PORTIONS
OF THE AREA.
IN THE WAKE OF THE LATE WEEKEND SYSTEM...ANOTHER SURGE OF ARCTIC AIR
WILL USHER IN EVEN COLDER AIR WITH 850 MB TEMPERATURES IN THE -20 TO
-25C RANGE. AIDED BY A POSSIBLE FRESH SNOWPACK...WIDESPREAD MORNING
TEMPERATURES IN THE SINGLE DIGITS BELOW ZERO ARE LIKELY WITH TEENS
BELOW ZERO POSSIBLE IN SPOTS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1111 PM CST WED DEC 4 2013
WINDS HAVE INCREASED POST A COLD FRONT...AND WILL STAY STRONG AND
GUSTY FROM THE WEST/NORTHWEST THROUGH THURSDAY EVENING. DON/T SEE A
LLWS THREAT AT THIS TIME.
CIGS ARE PROBLEMATIC AND CONFIDENCE IS NOT HIGH IN WHEN THE MVFR
/TO IFR/ CLOUD DECK WILL CLIMB/CLEAR. BUFKIT SOUNDINGS AND LOW LEVEL
MOISTURE FIELDS CONTINUE TO KEEP SOME SATURATION UNDER AN INVERSION
THROUGH THE BETTER PART OF THU. SOUNDINGS DO SUGGEST SOME
IMPROVEMENT ON THU...WITH SOME INCREASE IN CIG HEIGHTS...BUT LIKELY
STAYING MVFR. THESE 1500-2500 KFT CIGS COULD HANG AROUND INTO EARLY
FRIDAY MORNING. LATEST FOG/STRATUS SATELLITE IMAGERY POINTS TO
CLEARING OVER WESTERN MN...BUT VAD/PROFILER WINDS ARE WEST TO
NORTHWEST...SUGGESTING THIS CLEARING WILL STAY NORTH OF THE
KRST/KLSE. GOING TO STAY PESSIMISTIC WITH THE MVFR CIGS FOR NOW AND
HOLD THEM THROUGH MUCH OF THU...BRINGING VFR IN FOR THE EVENING
HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ZT
LONG TERM....ZT
AVIATION.....RIECK
AREA FORECAST DISCUSSION...UPDATE
NWS PEACHTREE CITY GA
1030 AM EST THU DEC 5 2013
.UPDATE...
HAVE MADE NO CHANGES TO THE ZONES. PERIODS OF LIGHT RAIN OR DRIZZLE
WILL CONTINUE INTO THE AFTERNOON AS STRONG SOUTHERLY FLOW CONTINUES
ALOFT.
41
.UPDATE...
A QUICK UPDATE TO ACCOUNT FOR CURRENT RADAR TRENDS. FORECAST WILL
BE ISSUED SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 425 AM EST THU DEC 5 2013/
SHORT TERM /TODAY THROUGH FRIDAY/...
SHORT TERM MODELS ARE IN GOOD AGREEMENT...BUT CONTINUE TO HAVE
ISSUES WITH IMPULSES MOVING THROUGH THE UPPER LEVEL FLOW WHICH ARE
PRODUCING AREAS OF RAIN ACROSS THE FORECAST AREA. UPPER LEVEL
RIDGING BUILDS OVER FL/SE GA AS BROAD LONG WAVE TROUGH MOVES ACROSS
THE DESERT SOUTHWEST. THE SUBTLE IMPULSES MAKE IT HARD TO PINPOINT
EXACT TIMING OF RAIN TRENDS. THE RAP HAS HAD A GOOD HANDLE ON THE
AREA OF RAIN MOVING ACROSS PORTIONS OF CENTRAL GA AND LEANED HEAVILY
TOWARD RAP SOLUTION IN THE NEAR TERM. AREA OF RAIN WILL MOVE VERY
CLOSE TO ATLANTA BUT MAINLY IMPACT SOUTH AND EAST PORTIONS OF THE
METRO AREA IN THE EARLY PORTIONS OF THE MORNING RUSH HOUR...
IMPACTING AREAS NORTH OF MACON AND ATHENS THROUGH 8AM BEFORE EXITING
THE FORECAST AREA. EARLIER AREA OF RAIN ALLOWED ATMOSPHERE OVER
NORTHEAST GA TO MIX..WINDS HAVE SHIFTED OUT OF THE SOUTH AND
SOUTHWEST AND VISIBILITIES HAVE INCREASED TO 1-2 MILES. WHILE
PATCHES OF DENSE FOG WILL BE POSSIBLE TOWARD MORNING WIDESPREAD
DENSE FOG IS NOT EXPECTED AND WILL DROP THE DENSE FOG ADVISORY AT
THIS TIME BUT CONTINUE TO MONITOR THE SITUATION.
SURFACE FRONT NEAR ARKLATEX WILL SLOWLY TREK ACROSS THE GULF COAST
STATES TODAY WITH GOOD GULF MOISTURE SPREADING AHEAD OF THE FRONT
ESPECIALLY INTO WESTERN PORTIONS OF FORECAST AREA. MODELS CONTINUE
TO SHOW MUCAPE OF 400-900 NORTH OF A LINE FROM AMERICUS TO
MILLEDGEVILLE. BEST SHEAR AXIS REMAINS WEST OF FORECAST AREA...
HOWEVER ENOUGH FOR ISOLATED THUNDER ACROSS NORTH AND WEST GA
18-06Z. SEVERE IS UNLIKELY AT THIS TIME BUT LATER SHIFTS WILL
CONTINUE TO MONITOR. FRONT STALLS OR DRIFTS SLOWLY SOUTHEAST ACROSS
FORECAST AREA THROUGH FRIDAY. MODELS SHOW AN INCREASED AXIS OF
INSTABILITY ONCE AGAIN FRIDAY AFTERNOON...ENOUGH TO WARRANT ISOLATED
THUNDER ONCE AGAIN
GUIDANCE TEMPERATURES LOOK IN LINE AND HAVE TAKEN A BLEND OF MAV AND
MET...LEANING TOWARD WARMER GUIDANCE EACH DAY. OVERNIGHT LOWS
TONIGHT WILL BE CLOSE TO BREAKING SOME OF THE RECORD HIGH MINIMUM
TEMPERATURES AT THE CLIMATE STATIONS.
ATWELL
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A WET AND UNSETTLED PATTERN WILL CONTINUE UNTIL TUESDAY.
MODELS SIMILAR WITH A SLOW MOVING COLD FRONT OVER N GA FORECAST TO
MOVE TO CENTRAL GA AND S DURING THE DAY SATURDAY. HIGHEST RAIN
CHANCES ACROSS N GA FRIDAY NIGHT AND OVER THE FORECAST AREA IN
GENERAL ON SATURDAY AS A MOIST SW FLOW ALOFT MOVES OVER THE ENTIRE
AREA.
GFS/EUROPEAN SIMILAR WITH COLD AIR DAMMING SETTING UP SUNDAY NIGHT
AND CONTINUING MONDAY. RAIN AND DRIZZLE CAN BE EXPECTED FOR MUCH
OF THE AREA...WITH THE SMALLEST CHANCES OVER THE SOUTHERN PORTION
OF CENTRAL GA.
GFS/EUROPEAN SIMILAR WITH BRINGING ANOTHER COLD FRONT INTO N GA
SUNDAY NIGHT AND INTO CENTRAL GA ON MONDAY THEN EXITING THE AREA
MONDAY NIGHT. HIGHEST RAIN CHANCES WILL CONTINUE OVER N AND PORTIONS
OF CENTRAL GA UNTIL TUESDAY WHEN PRECIP CHANCES WILL END. SOME
MUCAPE ASSOCIATED WITH THE COLD FRONT AND CONDITIONS WILL NEED TO BE
MONITORED FOR THE POTENTIAL OF STRONG TO SEVERE STORMS SUNDAY NIGHT
INTO MONDAY.
LARGE VARIATIONS OF TEMPERATURES CAN BE EXPECTED FROM N TO S UNTIL
MONDAY NIGHT AND TUESDAY WHEN THE PLUNGE TO COLDER TEMPERATURES
ACROSS THE AREA OCCURS.
BDL
CLIMATE...
RECORDS FOR 12-05
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAHN 77 1977 39 1984 59 1912 20 1935
1971 1886
1905
KATL 75 1998 33 1895 60 1998 20 1899
1977
KCSG 82 1977 45 1984 63 1994 26 1960
1957
KMCN 80 1977 44 1945 64 1912 22 2000
1901
RECORDS FOR 12-06
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAHN 77 1998 37 1992 59 1912 20 1937
1962
KATL 75 2001 25 1937 57 2011 14 1937
1998
1912
KCSG 78 1951 42 1992 63 2011 24 1962
1962
KMCN 78 1924 33 1937 63 1912 20 1937
PREV DISCUSSION... /ISSUED 639 AM EST THU DEC 5 2013/
AVIATION...
12Z UPDATE...
TAF SITES ARE A MIX IFR/LIFR...WITH AN IMPROVEMENT TO MVFR
EXPECTED BETWEEN 15-16Z. AN AREA OF RAIN WILL IMPACT MCN/AHN. SHRA
AND ISOLATED TS EXPECTED BY AFTERNOON BUT PROBABILITY IS LOW AND
HAVE LEFT IT OUT OF TAF SITES FOR NOW. WINDS ARE SOUTH WITH ATL
MAINLY SOUTHWEST...WIND SPEEDS SHOULD BE 5-10KTS.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON CIGS/WIND DIRECTION.
MEDIUM TO HIGH CONFIDENCE ON WIND SPEEDS/VISIBILITY/WEATHER.
ATWELL
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 60 76 56 / 50 50 30 50
ATLANTA 72 62 74 49 / 50 50 70 80
BLAIRSVILLE 66 60 66 46 / 60 80 90 100
CARTERSVILLE 72 63 75 45 / 50 60 90 100
COLUMBUS 76 63 79 55 / 50 40 20 60
GAINESVILLE 67 61 72 51 / 50 60 70 80
MACON 76 61 80 60 / 50 20 20 40
ROME 74 62 74 45 / 60 70 100 100
PEACHTREE CITY 72 64 77 49 / 50 40 60 80
VIDALIA 76 62 81 63 / 50 20 10 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ATWELL
LONG TERM....BDL
AVIATION...41
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
649 AM EST THU DEC 5 2013
.UPDATE...
A QUICK UPDATE TO ACCOUNT FOR CURRENT RADAR TRENDS. FORECAST WILL
BE ISSUED SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 425 AM EST THU DEC 5 2013/
SHORT TERM /TODAY THROUGH FRIDAY/...
SHORT TERM MODELS ARE IN GOOD AGREEMENT...BUT CONTINUE TO HAVE
ISSUES WITH IMPULSES MOVING THROUGH THE UPPER LEVEL FLOW WHICH ARE
PRODUCING AREAS OF RAIN ACROSS THE FORECAST AREA. UPPER LEVEL
RIDGING BUILDS OVER FL/SE GA AS BROAD LONG WAVE TROUGH MOVES ACROSS
THE DESERT SOUTHWEST. THE SUBTLE IMPULSES MAKE IT HARD TO PINPOINT
EXACT TIMING OF RAIN TRENDS. THE RAP HAS HAD A GOOD HANDLE ON THE
AREA OF RAIN MOVING ACROSS PORTIONS OF CENTRAL GA AND LEANED HEAVILY
TOWARD RAP SOLUTION IN THE NEAR TERM. AREA OF RAIN WILL MOVE VERY
CLOSE TO ATLANTA BUT MAINLY IMPACT SOUTH AND EAST PORTIONS OF THE
METRO AREA IN THE EARLY PORTIONS OF THE MORNING RUSH HOUR...
IMPACTING AREAS NORTH OF MACON AND ATHENS THROUGH 8AM BEFORE EXITING
THE FORECAST AREA. EARLIER AREA OF RAIN ALLOWED ATMOSPHERE OVER
NORTHEAST GA TO MIX..WINDS HAVE SHIFTED OUT OF THE SOUTH AND
SOUTHWEST AND VISIBILITIES HAVE INCREASED TO 1-2 MILES. WHILE
PATCHES OF DENSE FOG WILL BE POSSIBLE TOWARD MORNING WIDESPREAD
DENSE FOG IS NOT EXPECTED AND WILL DROP THE DENSE FOG ADVISORY AT
THIS TIME BUT CONTINUE TO MONITOR THE SITUATION.
SURFACE FRONT NEAR ARKLATEX WILL SLOWLY TREK ACROSS THE GULF COAST
STATES TODAY WITH GOOD GULF MOISTURE SPREADING AHEAD OF THE FRONT
ESPECIALLY INTO WESTERN PORTIONS OF FORECAST AREA. MODELS CONTINUE
TO SHOW MUCAPE OF 400-900 NORTH OF A LINE FROM AMERICUS TO
MILLEDGEVILLE. BEST SHEAR AXIS REMAINS WEST OF FORECAST AREA...
HOWEVER ENOUGH FOR ISOLATED THUNDER ACROSS NORTH AND WEST GA
18-06Z. SEVERE IS UNLIKELY AT THIS TIME BUT LATER SHIFTS WILL
CONTINUE TO MONITOR. FRONT STALLS OR DRIFTS SLOWLY SOUTHEAST ACROSS
FORECAST AREA THROUGH FRIDAY. MODELS SHOW AN INCREASED AXIS OF
INSTABILITY ONCE AGAIN FRIDAY AFTERNOON...ENOUGH TO WARRANT ISOLATED
THUNDER ONCE AGAIN
GUIDANCE TEMPERATURES LOOK IN LINE AND HAVE TAKEN A BLEND OF MAV AND
MET...LEANING TOWARD WARMER GUIDANCE EACH DAY. OVERNIGHT LOWS
TONIGHT WILL BE CLOSE TO BREAKING SOME OF THE RECORD HIGH MINIMUM
TEMPERATURES AT THE CLIMATE STATIONS.
ATWELL
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A WET AND UNSETTLED PATTERN WILL CONTINUE UNTIL TUESDAY.
MODELS SIMILAR WITH A SLOW MOVING COLD FRONT OVER N GA FORECAST TO
MOVE TO CENTRAL GA AND S DURING THE DAY SATURDAY. HIGHEST RAIN
CHANCES ACROSS N GA FRIDAY NIGHT AND OVER THE FORECAST AREA IN
GENERAL ON SATURDAY AS A MOIST SW FLOW ALOFT MOVES OVER THE ENTIRE
AREA.
GFS/EUROPEAN SIMILAR WITH COLD AIR DAMMING SETTING UP SUNDAY NIGHT
AND CONTINUING MONDAY. RAIN AND DRIZZLE CAN BE EXPECTED FOR MUCH
OF THE AREA...WITH THE SMALLEST CHANCES OVER THE SOUTHERN PORTION
OF CENTRAL GA.
GFS/EUROPEAN SIMILAR WITH BRINGING ANOTHER COLD FRONT INTO N GA
SUNDAY NIGHT AND INTO CENTRAL GA ON MONDAY THEN EXITING THE AREA
MONDAY NIGHT. HIGHEST RAIN CHANCES WILL CONTINUE OVER N AND PORTIONS
OF CENTRAL GA UNTIL TUESDAY WHEN PRECIP CHANCES WILL END. SOME
MUCAPE ASSOCIATED WITH THE COLD FRONT AND CONDITIONS WILL NEED TO BE
MONITORED FOR THE POTENTIAL OF STRONG TO SEVERE STORMS SUNDAY NIGHT
INTO MONDAY.
LARGE VARIATIONS OF TEMPERATURES CAN BE EXPECTED FROM N TO S UNTIL
MONDAY NIGHT AND TUESDAY WHEN THE PLUNGE TO COLDER TEMPERATURES
ACROSS THE AREA OCCURS.
BDL
CLIMATE...
RECORDS FOR 12-05
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAHN 77 1977 39 1984 59 1912 20 1935
1971 1886
1905
KATL 75 1998 33 1895 60 1998 20 1899
1977
KCSG 82 1977 45 1984 63 1994 26 1960
1957
KMCN 80 1977 44 1945 64 1912 22 2000
1901
RECORDS FOR 12-06
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAHN 77 1998 37 1992 59 1912 20 1937
1962
KATL 75 2001 25 1937 57 2011 14 1937
1998
1912
KCSG 78 1951 42 1992 63 2011 24 1962
1962
KMCN 78 1924 33 1937 63 1912 20 1937
PREV DISCUSSION... /ISSUED 639 AM EST THU DEC 5 2013/
AVIATION...
12Z UPDATE...
TAF SITES ARE A MIX IFR/LIFR...WITH AN IMPROVEMENT TO MVFR
EXPECTED BETWEEN 15-16Z. AN AREA OF RAIN WILL IMPACT MCN/AHN. SHRA
AND ISOLATED TS EXPECTED BY AFTERNOON BUT PROBABILITY IS LOW AND
HAVE LEFT IT OUT OF TAF SITES FOR NOW. WINDS ARE SOUTH WITH ATL
MAINLY SOUTHWEST...WIND SPEEDS SHOULD BE 5-10KTS.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON CIGS/WIND DIRECTION.
MEDIUM TO HIGH CONFIDENCE ON WIND SPEEDS/VISIBILITY/WEATHER.
ATWELL
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 60 76 56 / 50 50 30 50
ATLANTA 72 62 74 49 / 50 50 70 80
BLAIRSVILLE 66 60 66 46 / 60 80 90 100
CARTERSVILLE 72 63 75 45 / 50 60 90 100
COLUMBUS 76 63 79 55 / 50 40 20 60
GAINESVILLE 67 61 72 51 / 50 60 70 80
MACON 76 61 80 60 / 50 20 20 40
ROME 74 62 74 45 / 60 70 100 100
PEACHTREE CITY 72 64 77 49 / 50 40 60 80
VIDALIA 76 62 81 63 / 50 20 10 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ATWELL
LONG TERM....BDL
AVIATION...ATWELL
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
639 AM EST THU DEC 5 2013
.PREV DISCUSSION... /ISSUED 425 AM EST THU DEC 5 2013/
SHORT TERM /TODAY THROUGH FRIDAY/...
SHORT TERM MODELS ARE IN GOOD AGREEMENT...BUT CONTINUE TO HAVE
ISSUES WITH IMPULSES MOVING THROUGH THE UPPER LEVEL FLOW WHICH ARE
PRODUCING AREAS OF RAIN ACROSS THE FORECAST AREA. UPPER LEVEL
RIDGING BUILDS OVER FL/SE GA AS BROAD LONG WAVE TROUGH MOVES ACROSS
THE DESERT SOUTHWEST. THE SUBTLE IMPULSES MAKE IT HARD TO PINPOINT
EXACT TIMING OF RAIN TRENDS. THE RAP HAS HAD A GOOD HANDLE ON THE
AREA OF RAIN MOVING ACROSS PORTIONS OF CENTRAL GA AND LEANED HEAVILY
TOWARD RAP SOLUTION IN THE NEAR TERM. AREA OF RAIN WILL MOVE VERY
CLOSE TO ATLANTA BUT MAINLY IMPACT SOUTH AND EAST PORTIONS OF THE
METRO AREA IN THE EARLY PORTIONS OF THE MORNING RUSH HOUR...
IMPACTING AREAS NORTH OF MACON AND ATHENS THROUGH 8AM BEFORE EXITING
THE FORECAST AREA. EARLIER AREA OF RAIN ALLOWED ATMOSPHERE OVER
NORTHEAST GA TO MIX..WINDS HAVE SHIFTED OUT OF THE SOUTH AND
SOUTHWEST AND VISIBILITIES HAVE INCREASED TO 1-2 MILES. WHILE
PATCHES OF DENSE FOG WILL BE POSSIBLE TOWARD MORNING WIDESPREAD
DENSE FOG IS NOT EXPECTED AND WILL DROP THE DENSE FOG ADVISORY AT
THIS TIME BUT CONTINUE TO MONITOR THE SITUATION.
SURFACE FRONT NEAR ARKLATEX WILL SLOWLY TREK ACROSS THE GULF COAST
STATES TODAY WITH GOOD GULF MOISTURE SPREADING AHEAD OF THE FRONT
ESPECIALLY INTO WESTERN PORTIONS OF FORECAST AREA. MODELS CONTINUE
TO SHOW MUCAPE OF 400-900 NORTH OF A LINE FROM AMERICUS TO
MILLEDGEVILLE. BEST SHEAR AXIS REMAINS WEST OF FORECAST AREA...
HOWEVER ENOUGH FOR ISOLATED THUNDER ACROSS NORTH AND WEST GA
18-06Z. SEVERE IS UNLIKELY AT THIS TIME BUT LATER SHIFTS WILL
CONTINUE TO MONITOR. FRONT STALLS OR DRIFTS SLOWLY SOUTHEAST ACROSS
FORECAST AREA THROUGH FRIDAY. MODELS SHOW AN INCREASED AXIS OF
INSTABILITY ONCE AGAIN FRIDAY AFTERNOON...ENOUGH TO WARRANT ISOLATED
THUNDER ONCE AGAIN
GUIDANCE TEMPERATURES LOOK IN LINE AND HAVE TAKEN A BLEND OF MAV AND
MET...LEANING TOWARD WARMER GUIDANCE EACH DAY. OVERNIGHT LOWS
TONIGHT WILL BE CLOSE TO BREAKING SOME OF THE RECORD HIGH MINIMUM
TEMPERATURES AT THE CLIMATE STATIONS.
ATWELL
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A WET AND UNSETTLED PATTERN WILL CONTINUE UNTIL TUESDAY.
MODELS SIMILAR WITH A SLOW MOVING COLD FRONT OVER N GA FORECAST TO
MOVE TO CENTRAL GA AND S DURING THE DAY SATURDAY. HIGHEST RAIN
CHANCES ACROSS N GA FRIDAY NIGHT AND OVER THE FORECAST AREA IN
GENERAL ON SATURDAY AS A MOIST SW FLOW ALOFT MOVES OVER THE ENTIRE
AREA.
GFS/EUROPEAN SIMILAR WITH COLD AIR DAMMING SETTING UP SUNDAY NIGHT
AND CONTINUING MONDAY. RAIN AND DRIZZLE CAN BE EXPECTED FOR MUCH
OF THE AREA...WITH THE SMALLEST CHANCES OVER THE SOUTHERN PORTION
OF CENTRAL GA.
GFS/EUROPEAN SIMILAR WITH BRINGING ANOTHER COLD FRONT INTO N GA
SUNDAY NIGHT AND INTO CENTRAL GA ON MONDAY THEN EXITING THE AREA
MONDAY NIGHT. HIGHEST RAIN CHANCES WILL CONTINUE OVER N AND PORTIONS
OF CENTRAL GA UNTIL TUESDAY WHEN PRECIP CHANCES WILL END. SOME
MUCAPE ASSOCIATED WITH THE COLD FRONT AND CONDITIONS WILL NEED TO BE
MONITORED FOR THE POTENTIAL OF STRONG TO SEVERE STORMS SUNDAY NIGHT
INTO MONDAY.
LARGE VARIATIONS OF TEMPERATURES CAN BE EXPECTED FROM N TO S UNTIL
MONDAY NIGHT AND TUESDAY WHEN THE PLUNGE TO COLDER TEMPERATURES
ACROSS THE AREA OCCURS.
BDL
CLIMATE...
RECORDS FOR 12-05
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAHN 77 1977 39 1984 59 1912 20 1935
1971 1886
1905
KATL 75 1998 33 1895 60 1998 20 1899
1977
KCSG 82 1977 45 1984 63 1994 26 1960
1957
KMCN 80 1977 44 1945 64 1912 22 2000
1901
RECORDS FOR 12-06
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAHN 77 1998 37 1992 59 1912 20 1937
1962
KATL 75 2001 25 1937 57 2011 14 1937
1998
1912
KCSG 78 1951 42 1992 63 2011 24 1962
1962
KMCN 78 1924 33 1937 63 1912 20 1937
&&
.AVIATION...
12Z UPDATE...
TAF SITES ARE A MIX IFR/LIFR...WITH AN IMPROVEMENT TO MVFR
EXPECTED BETWEEN 15-16Z. AN AREA OF RAIN WILL IMPACT MCN/AHN. SHRA
AND ISOLATED TS EXPECTED BY AFTERNOON BUT PROBABILITY IS LOW AND
HAVE LEFT IT OUT OF TAF SITES FOR NOW. WINDS ARE SOUTH WITH ATL
MAINLY SOUTHWEST...WIND SPEEDS SHOULD BE 5-10KTS.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON CIGS/WIND DIRECTION.
MEDIUM TO HIGH CONFIDENCE ON WIND SPEEDS/VISIBILITY/WEATHER.
ATWELL
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 60 76 56 / 50 50 30 50
ATLANTA 72 62 74 49 / 50 50 70 80
BLAIRSVILLE 66 60 66 46 / 60 80 90 100
CARTERSVILLE 72 63 75 45 / 50 60 90 100
COLUMBUS 76 63 79 55 / 50 40 20 60
GAINESVILLE 67 61 72 51 / 50 60 70 80
MACON 76 61 80 60 / 50 20 20 40
ROME 74 62 74 45 / 60 70 100 100
PEACHTREE CITY 72 64 77 49 / 50 40 60 80
VIDALIA 76 62 81 63 / 50 20 10 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ATWELL
LONG TERM....BDL
AVIATION...ATWELL
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
816 AM CST THU DEC 5 2013
.DISCUSSION...
345 AM CST
MAIN FORECAST FOCUS IS ON COLDER TEMPERATURES WHICH WILL AFFECT THE
MIDWEST THROUGH THE PERIOD...AND THE POTENTIAL FOR SOME LIGHT SNOW
MAINLY SOUTHEAST OF THE CWA TONIGHT AND FRIDAY...AND ACROSS MUCH OF
THE FORECAST AREA SUNDAY AND SUNDAY NIGHT. A PUSH OF EVEN COLDER
ARCTIC AIR APPEARS POSSIBLE EARLY NEXT WEEK IN THE WAKE OF THE
WEEKEND SYSTEM...LIKELY ENHANCED BY FRESH SNOW COVER.
STRONG LOW PRESSURE WAS OVER EASTERN LAKE SUPERIOR EARLY THIS
MORNING...WITH ITS TRAILING COLD FRONT WELL EAST OF THE FORECAST
AREA FROM LOWER MICHIGAN TO THE LOWER OHIO VALLEY AND ARKLATEX.
COLDER/DRIER ARCTIC AIR WAS STEADILY SPREADING INTO THE MIDWEST WITH
TEMPS IN THE TEENS/LOWER 20S AND DEW POINTS IN THE SINGLE DIGITS AND
TEENS. COLD ADVECTION WILL LIKELY OFFSET ANY DIURNAL WARMING TODAY
WITH TEMPS EXPECTED TO DIP A LITTLE MORE THIS MORNING THEN BECOME
STEADY. THOUGH APPROACHING AIR MASS IS DRIER...THERE IS CONSIDERABLE
LOW CLOUDINESS WITHIN COLD ADVECTION AND EVEN A NARROW BAND OF
FLURRIES OR LIGHT SNOW ACROSS FAR EASTERN IOWA AND NORTHWEST
ILLINOIS AT THIS HOUR. THIS APPEARS TO BE DRIVEN BY SHORT WAVE
ENERGY AND A TIGHTENING IN THE THERMAL GRADIENT AROUND NEAR 800
MB...WHICH THE RAP DEPICTS NICELY WITH AN AREA OF FRONTOGENESIS
CLOSELY TIED TO CURRENT RADAR RETURNS. THE RAP CONTINUES TO SPREAD
THIS FORCING INTO NORTH CENTRAL AND FAR NORTHERN IL EARLY THIS
MORNING BEFORE RAPIDLY WEAKENING IT PRIOR TO MIDDAY. LOW LEVEL CLOUD
COVER WILL LIKELY ERODE BY THIS AFTERNOON...THOUGH PRESENCE OF
STRONG SOUTHWESTERLY JET ALOFT AND ADDITIONAL MINOR AMPLITUDE
MID-LEVEL WAVES WILL LIKELY KEEP SOME DEGREE OF MID/HIGH CLOUDS
AROUND THROUGH THE DAY. FARTHER TO THE SOUTHEAST...SERIES OF FAST
MOVING MID-LEVEL DISTURBANCES WILL HELP TIGHTEN LOW LEVEL BAROCLINIC
ZONE ACROSS THE OHIO VALLEY...FRONT FRONTOGENETIC BANDING DEVELOPING
SNOW FROM SOUTHERN MISSOURI INTO OHIO. MODEL GUIDANCE CONTINUES TO
FOCUS AXIS OF ACCUMULATING SNOWFALL SOUTHEAST OF THE CWA LATER TODAY
INTO FRIDAY...WITH FARTHEST NORTH SOLUTIONS CLIPPING SOUTHEAST TIER
OF WFO LOT CWA COUNTIES WITH AT BEST A MINOR ACCUMULATION OF LESS
THAN A HALF INCH WITH DISTURBANCES THIS EVENING AND AGAIN FRIDAY
MIDDAY/AFTERNOON.
LITTLE CHANGE IN THINKING WITH RESPECT TO TEMPERATURES TODAY THROUGH
SATURDAY...WITH PERSISTENT INTRUSION OF ARCTIC AIR INTO FRIDAY AND
SATURDAY AS SURFACE HIGH PRESSURE EVENTUALLY BUILDS INTO THE REGION.
GUIDANCE REMAINS IN DECENT AGREEMENT WITH THE GENERAL TREND OF
20S/LOW 30S TODAY...THEN HIGHS IN THE UPPER TEENS TO LOW 20S FRI/SAT
WITH LOWS RANGING FROM THE SINGLE DIGITS NORTHWEST TO THE TEENS
SOUTHEAST.
ENERGY NOTED IN WATER VAPOR IMAGERY CURRENTLY DIGGING SOUTH INTO
BRITISH COLUMBIA IS PROGGED TO AMPLIFY OVER THE WEST COAST OVER THE
NEXT COUPLE OF DAYS...THEN MOVE EAST ACROSS THE ROCKIES AND PLAINS
SUNDAY AND ACROSS THE GREAT LAKES REGION SUNDAY NIGHT. WHILE SOME
MINOR DETAIL DIFFERENCES REMAIN IN THE LONGER RANGE MODEL
GUIDANCE...THERE IS DECENT CONSENSUS IN A BROAD SURFACE LOW
DEVELOPING ACROSS THE REGION AND LIFTING NORTHEAST ACROSS THE GREAT
LAKES SUNDAY NIGHT AND EARLY MONDAY. DRY EASTERLY FLOW IN MODIFIED
ARCTIC AIR WILL LIKELY BE A BIT SLOW TO SATURATE AS WARM/MOIST
ADVECTION DEVELOPS IN ADVANCE OF THIS SYSTEM SUNDAY...THOUGH LIGHT
SNOW IS EXPECTED TO DEVELOP FROM THE WEST/SOUTHWEST THROUGH THE
AFTERNOON. SNOW IS THEN EXPECTED SUNDAY NIGHT INTO EARLY MONDAY
MORNING...WITH CURRENT MODEL QPF SUGGESTING PERHAPS 2-3 INCHES
ACROSS ESPECIALLY THE CENTRAL AND NORTHWEST PARTS OF THE FORECAST
AREA BEFORE TAPERING TO FLURRIES MONDAY MORNING. IF THIS SNOW COVER
DOES MATERIALIZE...ANOTHER BRIEF SHOT OF ARCTIC AIR WOULD LIKELY
PRODUCE COLDER TEMPS EARLY/MID NEXT WEEK. COLDEST PERHAPS WOULD BE
TUESDAY MORNING...WHEN WEAK RIDGE AXIS WOULD SUPPORT BEST
RADIATIONAL COOLING.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* MVFR CEILINGS SCATTERING OUT TO VFR CEILINGS LATE THIS MORNING.
* GUSTY WEST WINDS TODAY...DIMINISHING AND VEERING NORTHWEST
TONIGHT.
TRS
//DISCUSSION...UPDATED 12Z...
DESPITE POCKETS OF VFR THE TREND THIS MORNING IS MORE LIKELY TO BE
GRADUALLY IMPROVING MVFR. SLOWED DOWN THE ARRIVAL OF HIGHER CIGS
COMPARED TO EARLIER TAFS BASED ON UPSTREAM OBS AND LATEST GUIDANCE
PRODUCTS. GUSTY WEST WINDS WILL VERY GRADUALLY VEER NORTHWESTERLY
AND BY EARLY THIS EVENING WE SHOULD LOSE THE GUSTS. ALSO INCLUDED
PERIODS OF LIGHT SNOW THIS MORNING WHICH ACTUALLY IS EXPECTED TO
BE MORE LIKE FLURRIES AND HOPEFULLY NOT ANY SORT OF PROBLEM.
LENNING
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN TIMING OF LOSS OF MVFR CEILINGS THIS
MORNING.
* HIGH CONFIDENCE IN WIND TRENDS AND OTHER ELEMENTS.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT AND SATURDAY...VFR.
SUNDAY...CHANCE OF SNOW...ESPECIALLY LATE. MVFR OR LOWER POSSIBLE.
MONDAY...CHANCE OF SNOW WITH MVFR OR LOWER EARLY.
TUESDAY AND WEDNESDAY...MAINLY VFR.
LENNING
&&
.MARINE...
321 AM CST
LOW PRESSURE CROSSING LAKE SUPERIOR INTO ONTARIO THIS MORNING
DRAGGED A COLD FRONT ACROSS THE LAKE LAST EVENING. WINDS TURNED
SOUTHWEST BEHIND THE FRONT BUT ARE VEERING TO WEST THIS MORNING
AND WILL CONTINUE VEERING TO NORTHWEST TONIGHT. IN THE TIGHTER
PRESSURE GRADIENT ACROSS THE NORTHERN HALF OF THE LAKE CLOSER TO
THE LOW...GALES TO 40 KTS WITH POSSIBLY HIGHER GUSTS ARE EXPECTED
TO PERSIST INTO THIS EVENING. THE SOUTHERN HALF OF THE LAKE ALSO
WILL BE WINDY...BUT GALE FORCE GUSTS ARE EXPECTED TO BE
CONSIDERABLY LESS FREQUENT ACROSS THE SOUTH HALF. LATEST 3 AM CST
SHIP OBS IN THE FAR SOUTHERN PART OF THE LAKE HAD WIND SPEEDS
ONLY IN THE TEENS...WHILE SHIP OBS IN THE NORTHERN LAKE HAD WINDS
IN THE MID 30 KNOT RANGE.
DEBATED WHETHER TO TRIM THE END OF THE SMALL CRAFT ADVISORY FOR
THE INDIANA NEARSHORE WATERS AS THE PRESSURE GRADIENT FALLS OFF
QUICKLY THIS EVENING. DECIDED WITH SUCH COLD AIR AND A NORTHWEST
FETCH...WAVES SHOULD BE EASY TO MAINTAIN...AND GUSTS INTO THE MID
20 KNOT RANGE MAY WELL PERSIST INTO THE OVERNIGHT HOURS.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868 UNTIL 9 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 3 PM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM FRIDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
551 AM CST THU DEC 5 2013
.DISCUSSION...
345 AM CST
MAIN FORECAST FOCUS IS ON COLDER TEMPERATURES WHICH WILL AFFECT THE
MIDWEST THROUGH THE PERIOD...AND THE POTENTIAL FOR SOME LIGHT SNOW
MAINLY SOUTHEAST OF THE CWA TONIGHT AND FRIDAY...AND ACROSS MUCH OF
THE FORECAST AREA SUNDAY AND SUNDAY NIGHT. A PUSH OF EVEN COLDER
ARCTIC AIR APPEARS POSSIBLE EARLY NEXT WEEK IN THE WAKE OF THE
WEEKEND SYSTEM...LIKELY ENHANCED BY FRESH SNOW COVER.
STRONG LOW PRESSURE WAS OVER EASTERN LAKE SUPERIOR EARLY THIS
MORNING...WITH ITS TRAILING COLD FRONT WELL EAST OF THE FORECAST
AREA FROM LOWER MICHIGAN TO THE LOWER OHIO VALLEY AND ARKLATEX.
COLDER/DRIER ARCTIC AIR WAS STEADILY SPREADING INTO THE MIDWEST WITH
TEMPS IN THE TEENS/LOWER 20S AND DEW POINTS IN THE SINGLE DIGITS AND
TEENS. COLD ADVECTION WILL LIKELY OFFSET ANY DIURNAL WARMING TODAY
WITH TEMPS EXPECTED TO DIP A LITTLE MORE THIS MORNING THEN BECOME
STEADY. THOUGH APPROACHING AIR MASS IS DRIER...THERE IS CONSIDERABLE
LOW CLOUDINESS WITHIN COLD ADVECTION AND EVEN A NARROW BAND OF
FLURRIES OR LIGHT SNOW ACROSS FAR EASTERN IOWA AND NORTHWEST
ILLINOIS AT THIS HOUR. THIS APPEARS TO BE DRIVEN BY SHORT WAVE
ENERGY AND A TIGHTENING IN THE THERMAL GRADIENT AROUND NEAR 800
MB...WHICH THE RAP DEPICTS NICELY WITH AN AREA OF FRONTOGENESIS
CLOSELY TIED TO CURRENT RADAR RETURNS. THE RAP CONTINUES TO SPREAD
THIS FORCING INTO NORTH CENTRAL AND FAR NORTHERN IL EARLY THIS
MORNING BEFORE RAPIDLY WEAKENING IT PRIOR TO MIDDAY. LOW LEVEL CLOUD
COVER WILL LIKELY ERODE BY THIS AFTERNOON...THOUGH PRESENCE OF
STRONG SOUTHWESTERLY JET ALOFT AND ADDITIONAL MINOR AMPLITUDE
MID-LEVEL WAVES WILL LIKELY KEEP SOME DEGREE OF MID/HIGH CLOUDS
AROUND THROUGH THE DAY. FARTHER TO THE SOUTHEAST...SERIES OF FAST
MOVING MID-LEVEL DISTURBANCES WILL HELP TIGHTEN LOW LEVEL BAROCLINIC
ZONE ACROSS THE OHIO VALLEY...FRONT FRONTOGENETIC BANDING DEVELOPING
SNOW FROM SOUTHERN MISSOURI INTO OHIO. MODEL GUIDANCE CONTINUES TO
FOCUS AXIS OF ACCUMULATING SNOWFALL SOUTHEAST OF THE CWA LATER TODAY
INTO FRIDAY...WITH FARTHEST NORTH SOLUTIONS CLIPPING SOUTHEAST TIER
OF WFO LOT CWA COUNTIES WITH AT BEST A MINOR ACCUMULATION OF LESS
THAN A HALF INCH WITH DISTURBANCES THIS EVENING AND AGAIN FRIDAY
MIDDAY/AFTERNOON.
LITTLE CHANGE IN THINKING WITH RESPECT TO TEMPERATURES TODAY THROUGH
SATURDAY...WITH PERSISTENT INTRUSION OF ARCTIC AIR INTO FRIDAY AND
SATURDAY AS SURFACE HIGH PRESSURE EVENTUALLY BUILDS INTO THE REGION.
GUIDANCE REMAINS IN DECENT AGREEMENT WITH THE GENERAL TREND OF
20S/LOW 30S TODAY...THEN HIGHS IN THE UPPER TEENS TO LOW 20S FRI/SAT
WITH LOWS RANGING FROM THE SINGLE DIGITS NORTHWEST TO THE TEENS
SOUTHEAST.
ENERGY NOTED IN WATER VAPOR IMAGERY CURRENTLY DIGGING SOUTH INTO
BRITISH COLUMBIA IS PROGGED TO AMPLIFY OVER THE WEST COAST OVER THE
NEXT COUPLE OF DAYS...THEN MOVE EAST ACROSS THE ROCKIES AND PLAINS
SUNDAY AND ACROSS THE GREAT LAKES REGION SUNDAY NIGHT. WHILE SOME
MINOR DETAIL DIFFERENCES REMAIN IN THE LONGER RANGE MODEL
GUIDANCE...THERE IS DECENT CONSENSUS IN A BROAD SURFACE LOW
DEVELOPING ACROSS THE REGION AND LIFTING NORTHEAST ACROSS THE GREAT
LAKES SUNDAY NIGHT AND EARLY MONDAY. DRY EASTERLY FLOW IN MODIFIED
ARCTIC AIR WILL LIKELY BE A BIT SLOW TO SATURATE AS WARM/MOIST
ADVECTION DEVELOPS IN ADVANCE OF THIS SYSTEM SUNDAY...THOUGH LIGHT
SNOW IS EXPECTED TO DEVELOP FROM THE WEST/SOUTHWEST THROUGH THE
AFTERNOON. SNOW IS THEN EXPECTED SUNDAY NIGHT INTO EARLY MONDAY
MORNING...WITH CURRENT MODEL QPF SUGGESTING PERHAPS 2-3 INCHES
ACROSS ESPECIALLY THE CENTRAL AND NORTHWEST PARTS OF THE FORECAST
AREA BEFORE TAPERING TO FLURRIES MONDAY MORNING. IF THIS SNOW COVER
DOES MATERIALIZE...ANOTHER BRIEF SHOT OF ARCTIC AIR WOULD LIKELY
PRODUCE COLDER TEMPS EARLY/MID NEXT WEEK. COLDEST PERHAPS WOULD BE
TUESDAY MORNING...WHEN WEAK RIDGE AXIS WOULD SUPPORT BEST
RADIATIONAL COOLING.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* MVFR CEILINGS GRADUALLY IMPROVING THIS MORNING...WITH POCKETS OF VFR.
* GUSTY WEST WINDS TODAY...DIMINISHING AND VEERING NORTHWEST
TONIGHT.
* PERIODS OF FLURRIES OR LIGHT SNOW THIS MORNING.
LENNING
//DISCUSSION...UPDATED 12Z...
DESPITE POCKETS OF VFR THE TREND THIS MORNING IS MORE LIKELY TO BE
GRADUALLY IMPROVING MVFR. SLOWED DOWN THE ARRIVAL OF HIGHER CIGS
COMPARED TO EARLIER TAFS BASED ON UPSTREAM OBS AND LATEST GUIDANCE
PRODUCTS. GUSTY WEST WINDS WILL VERY GRADUALLY VEER NORTHWESTERLY
AND BY EARLY THIS EVENING WE SHOULD LOSE THE GUSTS. ALSO INCLUDED
PERIODS OF LIGHT SNOW THIS MORNING WHICH ACTUALLY IS EXPECTED TO
BE MORE LIKE FLURRIES AND HOPEFULLY NOT ANY SORT OF PROBLEM.
LENNING
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN TIMING OF HIGHER CEILINGS THIS MORNING.
* HIGH CONFIDENCE IN WIND TRENDS AND OTHER ELEMENTS.
LENNING
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT AND SATURDAY...VFR.
SUNDAY...CHANCE OF SNOW...ESPECIALLY LATE. MVFR OR LOWER POSSIBLE.
MONDAY...CHANCE OF SNOW WITH MVFR OR LOWER EARLY.
TUESDAY AND WEDNESDAY...MAINLY VFR.
LENNING
&&
.MARINE...
321 AM CST
LOW PRESSURE CROSSING LAKE SUPERIOR INTO ONTARIO THIS MORNING
DRAGGED A COLD FRONT ACROSS THE LAKE LAST EVENING. WINDS TURNED
SOUTHWEST BEHIND THE FRONT BUT ARE VEERING TO WEST THIS MORNING
AND WILL CONTINUE VEERING TO NORTHWEST TONIGHT. IN THE TIGHTER
PRESSURE GRADIENT ACROSS THE NORTHERN HALF OF THE LAKE CLOSER TO
THE LOW...GALES TO 40 KTS WITH POSSIBLY HIGHER GUSTS ARE EXPECTED
TO PERSIST INTO THIS EVENING. THE SOUTHERN HALF OF THE LAKE ALSO
WILL BE WINDY...BUT GALE FORCE GUSTS ARE EXPECTED TO BE
CONSIDERABLY LESS FREQUENT ACROSS THE SOUTH HALF. LATEST 3 AM CST
SHIP OBS IN THE FAR SOUTHERN PART OF THE LAKE HAD WIND SPEEDS
ONLY IN THE TEENS...WHILE SHIP OBS IN THE NORTHERN LAKE HAD WINDS
IN THE MID 30 KNOT RANGE.
DEBATED WHETHER TO TRIM THE END OF THE SMALL CRAFT ADVISORY FOR
THE INDIANA NEARSHORE WATERS AS THE PRESSURE GRADIENT FALLS OFF
QUICKLY THIS EVENING. DECIDED WITH SUCH COLD AIR AND A NORTHWEST
FETCH...WAVES SHOULD BE EASY TO MAINTAIN...AND GUSTS INTO THE MID
20 KNOT RANGE MAY WELL PERSIST INTO THE OVERNIGHT HOURS.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868 UNTIL 9 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 3 PM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM FRIDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS GRAY ME
919 AM EST THU DEC 5 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL MOVE INTO NEW ENGLAND ON TODAY...
SPREADING SOME LIGHT PRECIPITATION INTO THE REGION. THE FRONT WILL
PUSH OFFSHORE TONIGHT. A WAVE OF LOW PRESSURE WILL TRACK
NORTHEAST ALONG THE FRONT ON FRIDAY AND MAY SPREAD RAIN OR SNOW
INTO SOUTHERN AREAS. HIGH PRESSURE PUSHES THE FRONT FURTHER SOUTH
ON SATURDAY WITH COLDER AIR MOVING IN. HIGH PRESSURE SHIFTS EAST
ON SUNDAY WITH LOW PRESSURE TRACKING UP THE EAST COAST ON MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
855 AM...SFC WARM FRONT IS PROGRESSING NWD WITH LITTLE IN THE WAY
OF ANY PRECIP ATTM. ONLY PRECIP NEARBY IS LIGHT RA IN CENTRAL
MA/CT. PREV TREND IS FOR ANY RAIN TO MIX DOWN WARMER /ABV FRZING/
TEMPS AND WEAKEN INVERSION...THEREFORE THREAT OF ANY PATCHY FZRA
IS EXTREMELY S OF THE MTNS. CANNOT RULE OUT A FEW POCKETS OF FZRA
IN THE COLDER SPOTS OF THE MTNS THIS AFTERNOON...BUT THESE WOULD
BE SHORT-LIVED AND ISOLATED. OTHERWISE...LOOK FOR TEMPS TO SLOWLY
THROUGH THE DAY AND INTO THE EVENING.
UPDATE...
SOUTHERN AREAS CONTINUE TO SLOWLY WARM AS WARM AIR ADVECTION
REMAINS IN FULL SWING THIS MORNING. SOME VERY LIGHT ECHOES PER
LATEST 88D IMAGERY EXISTS OVER SOUTHERN NEW HAMPSHIRE EARLY THIS
MORNING. MUCH OF THIS PRECIPITATION IS NOT MAKING IT TO THE GROUND
DUE TO A DRY COLUMN IN PLACE OVER NORTHERN NEW ENGLAND.
WILL CONTINUE TO MONITOR FOR PATCHY FREEZING DRIZZLE. HOWEVER...NO
REPORTS AS OF 12Z. USED THE BTV TOP/DOWN WEATHER TOOL. WILL NOT BE
ISSUING AN ADVISORY WITH SUCH LOW CHANCE POPS FOR ICE THIS MORNING.
TIDES WILL NEED TO BE MONITORED ONCE AGAIN TODAY. SHOULD COME UP
CLOSE TO THE 12 FOOT FLOOD STAGE IN PORTLAND. HOWEVER...WITHOUT
MUCH WIND OR WAVE ACTION...PROBLEMS ARE NOT EXPECTED. HOWEVER...WATER LEVELS
IN HAMPTON WILL BE RUNNING HIGH TODAY.
PREV DISC...
MODELS HAVE BACKED OFF ON THE TIMING OF ANY PRECIPITATION IN
ASSOCIATION WITH THE APPROACHING FRONT EARLY THIS MORNING WITH
EACH CONSECUTIVE RUN. HOWEVER...A WEAK AREA OF LOW PRESSURE OFF
THE NEW JERSEY COASTLINE IS BEGINNING TO GENERATE SOME LOW LEVEL
PRECIPITATION IN THE FORM OF LIGHT DRIZZLE AND LIGHT RAIN. WITH
TEMPERATURES IN THE LOWER TO MIDDLE 20S ACROSS THE REGION...EXPECT
SOME OF THIS MAY FREEZE ON CONTACT IF IT ARRIVES EARLY ENOUGH
PRIOR TO OUR EXPECTED DAYTIME WARM UP TODAY. WILL CONTINUE TO
MONITOR THIS VERY CLOSELY AS LATEST HRRR RUN BRINGS LIGHT MIXED
PRECIPITATION INTO FAR SOUTHERN AREAS SHORTLY AFTER 12Z.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
FROPA FINALLY OCCURS TONIGHT...CHANGING THE PRECIPITATION FROM A
STRATIFORM TO A SHOWERY TYPE OF WEATHER. TEMPERATURES IN THE
MOUNTAINS WILL BE COOLING OFF...SO THERE MAY BE SOME LIGHT
ACCUMULATIONS IN ANY PERSISTENT SNOW SHOWERS OVER THE HIGH
TERRAIN. USED A BLEND OF MAV/MET MOS WHICH BRINGS TEMPERATURES IN
THE MOUNTAINS TO BELOW FREEZING BY FRIDAY MORNING.
MODELS ARE IN DISAGREEMENT BY LATE IN THE DAY ON FRIDAY AS TO
WHETHER A WAVE OF LOW PRESSURE WILL RIDE UP THE FRONT AND SOUTH OF
NEW ENGLAND OR NOT. CURRENTLY...THE NAM IS MOST AGGRESSIVE WITH THE
NORTHERN PROXIMITY OF PRECIPITATION...WHICH LEADS US TO THE LONG
RANGE PORTION OF THE FORECAST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
FRI NIGHT A WEAK WAVE OF LOW PRES WILL MOVE E ALONG A STALLED
FRONT LOCATED S OF NEW ENGL. SRN AREAS OF ME/NH WILL BE ON THE NRN
FRINGE OF THE PCPN SHIELD SO SOME LGT PCPN IS EXPECTED. THE PCPN
SHOULD PRODUCE PSBLY A FEW INCHES OF SNOW OVER SRN AREAS AS ANY
MIXED PCPN GRDLY CHANGES TO SNOW AS CAA OCCURS FRI NIGHT. BY SAT
MRNG SKIES CLEAR AS HIGH PRES BUILDS ACROSS THE REGION. HIGH PRES
BECOMES CENTERED OVER THE REGION SUN ALLOWING ANOTHER NICE DAY.
SUN NIGHT THE SFC/UPR RDG AXIS OVR NEW ENGL MOVES EWD ALLOWING A
MOIST SWLY FLOW TO DEVELOP AS A BROAD WAA PATTERN DEVELOPS AND
MOVES EWD INTO THE REGION BY MON MORNING. MODELS IN GENERAL
AGREEMENT THAT CONDS WILL BE COLD ENOUGH FOR SNOW AND SOME ACCUMS
EXPECTED AT THE ONSET MON MRNG BEFORE CHANGING OVER TO A MIX AND
THEN RAIN FROM S-N DURING THE DAY. BY MON NIGHT SYSTEM RAPIDLY
EXITS AND CLEARING EXPECTED AS A STRONG COLD FRONT MOVES THROUGH
THE REGION LATE IN THE SYSTEMS WAKE. TUES AND WED MUCH COLDER
TEMPS EXPECTED WITH BELOW NORMAL TEMPS EXPECTED.
ACCEPTED TIMING AND POPS OF SUPERBLEND GUID FOR DAYS 4-7.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
SHORT TERM...CONDITIONS GRADUALLY DETERIORATE THIS MORNING WITH LOW
CLOUDS AND POSSIBLY FOG/DRIZZLE MOVE IN. THIS COULD LEAD TO AN
EXTENDED PERIOD OF IFR OR LIFR CONDITIONS THROUGH TONIGHT...BEFORE
SLOWLY IMPROVING TO MVFR CONDITIONS ON FRIDAY.
LONG TERM...
FRI NIGHT IFR CONDS IN SNW OR MIXED PCPN OVER SRN AREAS WHILE NRN
AND CNTRL AREAS MAILY VFR. ON SAT CONDS BECOME VFR ACROSS ALL
AREAS AND CONTINUE THRU SUNDAY. THE NEXT SYSTEM APPROACHES SUN
NIGHT AND MON LOWERING CONDS TO IFR/LIFR ACROSS ALL AREAS.
&&
.MARINE...
SHORT TERM...SOUTHERLY FLOW TODAY WILL GRADUALLY BUILD 3 TO 5 FOOT
WAVES WITH TIME. WILL ISSUES SCA FOR SEAS...WHICH WILL CARRY ON
INTO FRIDAY. THIS IS FOR THE OUTER WATERS ONLY.
LONG TERM...
NO FLAGS FRI NIGHT AND SAT. NW WINDS MAY APPROACH SCA CONDS SUN.
ON MON AN INCRG E FLOW WILL PRODUCE SCA CONDS.
&&
.TIDES/COASTAL FLOODING...
KING TIDES PEAK TODAY AROUND MIDDAY...11.5 FT AT 1215 EST AT
PORTLAND...BUT WITH LIGHT WINDS AND MINIMAL WAVES...IMPACT SHOULD
BE LIMITED.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 PM THIS
AFTERNOON TO 4 PM EST FRIDAY FOR ANZ150-152-154.
&&
$$
SYNOPSIS...
NEAR TERM...CEMPA
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS GRAY ME
904 AM EST THU DEC 5 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL MOVE INTO NEW ENGLAND ON TODAY...
SPREADING SOME LIGHT PRECIPITATION INTO THE REGION. THE FRONT WILL
PUSH OFFSHORE TONIGHT. A WAVE OF LOW PRESSURE WILL TRACK
NORTHEAST ALONG THE FRONT ON FRIDAY AND MAY SPREAD RAIN OR SNOW
INTO SOUTHERN AREAS. HIGH PRESSURE PUSHES THE FRONT FURTHER SOUTH
ON SATURDAY WITH COLDER AIR MOVING IN. HIGH PRESSURE SHIFTS EAST
ON SUNDAY WITH LOW PRESSURE TRACKING UP THE EAST COAST ON MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
855 AM...SFC WARM FRONT IS PROGRESSING NWD WITH LITTLE IN THE WAY
OF ANY PRECIP ATTM. ONLY PRECIP NEARBY IS LIGHT RA IN CENTRAL
MA/CT. PREV TREND IS FOR ANY RAIN TO MIX DOWN WARMER /ABV FRZING/
TEMPS AND WEAKEN INVERSION...THEREFORE THREAT OF ANY PATCHY FZRA
IS EXTREMELY S OF THE MTNS. CANNOT RULE OUT A FEW POCKETS OF FZRA
IN THE COLDER SPOTS OF THE MTNS THIS AFTERNOON...BUT THESE WOULD
BE SHORT-LIVED AND ISOLATED. OTHERWISE...LOOK FOR TEMPS TO SLOWLY
THROUGH THE DAY AND INTO THE EVENING.
UPDATE...
SOUTHERN AREAS CONTINUE TO SLOWLY WARM AS WARM AIR ADVECTION
REMAINS IN FULL SWING THIS MORNING. SOME VERY LIGHT ECHOES PER
LATEST 88D IMAGERY EXISTS OVER SOUTHERN NEW HAMPSHIRE EARLY THIS
MORNING. MUCH OF THIS PRECIPITATION IS NOT MAKING IT TO THE GROUND
DUE TO A DRY COLUMN IN PLACE OVER NORTHERN NEW ENGLAND.
WILL CONTINUE TO MONITOR FOR PATCHY FREEZING DRIZZLE. HOWEVER...NO
REPORTS AS OF 12Z. USED THE BTV TOP/DOWN WEATHER TOOL. WILL NOT BE
ISSUING AN ADVISORY WITH SUCH LOW CHANCE POPS FOR ICE THIS MORNING.
TIDES WILL NEED TO BE MONITORED ONCE AGAIN TODAY. SHOULD COME UP
CLOSE TO THE 12 FOOT FLOOD STAGE IN PORTLAND. HOWEVER...WITHOUT
MUCH WIND OR WAVE ACTION...PROBLEMS ARE NOT EXPECTED. HOWEVER...WATER LEVELS
IN HAMPTON WILL BE RUNNING HIGH TODAY.
PREV DISC...
MODELS HAVE BACKED OFF ON THE TIMING OF ANY PRECIPITATION IN
ASSOCIATION WITH THE APPROACHING FRONT EARLY THIS MORNING WITH
EACH CONSECUTIVE RUN. HOWEVER...A WEAK AREA OF LOW PRESSURE OFF
THE NEW JERSEY COASTALINE IS BEGINNING TO GENERATE SOME LOW LEVEL
PRECIPITATION IN THE FORM OF LIGHT DRIZZLE AND LIGHT RAIN. WITH
TEMPERATURES IN THE LOWER TO MIDDLE 20S ACROSS THE REGION...EXPECT
SOME OF THIS MAY FREEZE ON CONTACT IF IT ARRIVES EARLY ENOUGH
PRIOR TO OUR EXPECTED DAYTIME WARMUP TODAY. WILL CONTINUE TO
MONITOR THIS VERY CLOSELY AS LATEST HRRR RUN BRINGS LIGHT MIXED
PRECIPITATION INTO FAR SOUTHERN AREAS SHORTLY AFTER 12Z.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
FROPA FINALLY OCCURS TONIGHT...CHANGING THE PRECIPITATION FROM A
STRATIFORM TO A SHOWERY TYPE OF WEATHER. TEMPERATURES IN THE
MOUNTAINS WILL BE COOLING OFF...SO THERE MAY BE SOME LIGHT
ACCUMULATIONS IN ANY PERSISTENT SNOW SHOWERS OVER THE HIGH
TERRAIN. USED A BLEND OF MAV/MET MOS WHICH BRINGS TEMPERATURES IN
THE MOUNTAINS TO BELOW FREEZING BY FRIDAY MORNING.
MODELS ARE IN DISAGREEMENT BY LATE IN THE DAY ON FRIDAY AS TO
WHETHER A WAVE OF LOW PRESSURE WILL RIDE UP THE FRONT AND SOUTH OF
NEW ENGLAND OR NOT. CURRENTLY...THE NAM IS MOST AGRESSIVE WITH THE
NORTHERN PROXIMITY OF PRECIPITATION...WHICH LEADS US TO THE LONG
RANGE PORTION OF THE FORECAST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
FRI NIGHT A WEAK WAVE OF LOW PRES WILL MOVE E ALONG A STALLED
FRONT LOCATED S OF NEW ENGL. SRN AREAS OF ME/NH WILL BE ON THE NRN
FRINGE OF THE PCPN SHIELD SO SOME LGT PCPN IS EXPECTED. THE PCPN
SHOULD PRODUCE PSBLY A FEW INCHES OF SNOW OVER SRN AREAS AS ANY
MIXED PCPN GRDLY CHANGES TO SNOW AS CAA OCCURS FRI NIGHT. BY SAT
MRNG SKIES CLEAR AS HIGH PRES BUILDS ACROSS THE REGION. HIGH PRES
BECOMES CENTERED OVER THE REGION SUN ALLOWING ANOTHER NICE DAY.
SUN NIGHT THE SFC/UPR RDG AXIS OVR NEW ENGL MOVES EWD ALLOWING A
MOIST SWLY FLOW TO DEVELOP AS A BROAD WAA PATTERN DEVELOPS AND
MOVES EWD INTO THE REGION BY MON MORNING. MODELS IN GENERAL
AGREEMENT THAT CONDS WILL BE COLD ENOUGH FOR SNOW AND SOME ACCUMS
EXPECTED AT THE ONSET MON MRNG BEFORE CHANGING OVER TO A MIX AND
THEN RAIN FROM S-N DURING THE DAY. BY MON NIGHT SYSTEM RAPIDLY
EXITS AND CLEARING EXPECTED AS A STRONG COLD FRONT MOVES THROUGH
THE REGION LATE IN THE SYSTEMS WAKE. TUES AND WED MUCH COLDER
TEMPS EXPECTED WITH BELOW NORMAL TEMPS EXPECTED.
ACCEPTED TIMING AND POPS OF SUPERBLEND GUID FOR DAYS 4-7.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
SHORT TERM...CONDITIONS GRADUALLY DETERIORATE THIS MORNING WITH LOW
CLOUDS AND POSSIBLY FOG/DRIZZLE MOVE IN. THIS COULD LEAD TO AN
EXTENDED PERIOD OF IFR OR LIFR CONDITIONS THROUGH TONIGHT...BEFORE
SLOWLY IMPROVING TO MVFR CONDITIONS ON FRIDAY.
LONG TERM...
FRI NIGHT IFR CONDS IN SNW OR MIXED PCPN OVER SRN AREAS WHILE NRN
AND CNTRL AREAS MAILY VFR. ON SAT CONDS BECOME VFR ACROSS ALL
AREAS AND CONTINUE THRU SUNDAY. THE NEXT SYSTEM APPROACHES SUN
NIGHT AND MON LOWERING CONDS TO IFR/LIFR ACROSS ALL AREAS.
&&
.MARINE...
SHORT TERM...SOUTHERLY FLOW TODAY WILL GRADUALLY BUILD 3 TO 5 FOOT
WAVES WITH TIME. WILL ISSUES SCA FOR SEAS...WHICH WILL CARRY ON
INTO FRIDAY. THIS IS FOR THE OUTER WATERS ONLY.
LONG TERM...
NO FLAGS FRI NIGHT AND SAT. NW WINDS MAY APPROACH SCA CONDS SUN.
ON MON AN INCRG E FLOW WILL PRODUCE SCA CONDS.
&&
.TIDES/COASTAL FLOODING...
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 PM THIS
AFTERNOON TO 4 PM EST FRIDAY FOR ANZ150-152-154.
&&
$$
SYNOPSIS...
NEAR TERM...CEMPA
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS GRAY ME
712 AM EST THU DEC 5 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL MOVE INTO NEW ENGLAND ON TODAY...
SPREADING SOME LIGHT PRECIPITATION INTO THE REGION. THE FRONT WILL
PUSH OFFSHORE TONIGHT. A WAVE OF LOW PRESSURE WILL TRACK
NORTHEAST ALONG THE FRONT ON FRIDAY AND MAY SPREAD RAIN OR SNOW
INTO SOUTHERN AREAS. HIGH PRESSURE PUSHES THE FRONT FURTHER SOUTH
ON SATURDAY WITH COLDER AIR MOVING IN. HIGH PRESSURE SHIFTS EAST
ON SUNDAY WITH LOW PRESSURE TRACKING UP THE EAST COAST ON MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
SOUTHERN AREAS CONTINUE TO SLOWLY WARM AS WARM AIR ADVECTION
REMAINS IN FULL SWING THIS MORNING. SOME VERY LIGHT ECHOES PER
LATEST 88D IMAGERY EXISTS OVER SOUTHERN NEW HAMPSHIRE EARLY THIS
MORNING. MUCH OF THIS PRECIPITATION IS NOT MAKING IT TO THE GROUND
DUE TO A DRY COLUMN IN PLACE OVER NORTHERN NEW ENGLAND.
WILL CONTINUE TO MONITOR FOR PATCHY FREEZING DRIZZLE. HOWEVER...NO
REPORTS AS OF 12Z. USED THE BTV TOP/DOWN WEATHER TOOL. WILL NOT BE
ISSUING AN ADVISORY WITH SUCH LOW CHANCE POPS FOR ICE THIS MORNING.
TIDES WILL NEED TO BE MONITORED ONCE AGAIN TODAY. SHOULD COME UP
CLOSE TO THE 12 FOOT FLOOD STAGE IN PORTLAND. HOWEVER...WITHOUT
MUCH WIND OR WAVE ACTION...PROBLEMS ARE NOT EXPECTED. HOWEVER...WATER LEVELS
IN HAMPTON WILL BE RUNNING HIGH TODAY.
PREV DISC...
MODELS HAVE BACKED OFF ON THE TIMING OF ANY PRECIPITATION IN
ASSOCIATION WITH THE APPROACHING FRONT EARLY THIS MORNING WITH
EACH CONSECUTIVE RUN. HOWEVER...A WEAK AREA OF LOW PRESSURE OFF
THE NEW JERSEY COASTALINE IS BEGINNING TO GENERATE SOME LOW LEVEL
PRECIPITATION IN THE FORM OF LIGHT DRIZZLE AND LIGHT RAIN. WITH
TEMPERATURES IN THE LOWER TO MIDDLE 20S ACROSS THE REGION...EXPECT
SOME OF THIS MAY FREEZE ON CONTACT IF IT ARRIVES EARLY ENOUGH
PRIOR TO OUR EXPECTED DAYTIME WARMUP TODAY. WILL CONTINUE TO
MONITOR THIS VERY CLOSELY AS LATEST HRRR RUN BRINGS LIGHT MIXED
PRECIPITATION INTO FAR SOUTHERN AREAS SHORTLY AFTER 12Z.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
FROPA FINALLY OCCURS TONIGHT...CHANGING THE PRECIPITATION FROM A
STRATIFORM TO A SHOWERY TYPE OF WEATHER. TEMPERATURES IN THE
MOUNTAINS WILL BE COOLING OFF...SO THERE MAY BE SOME LIGHT
ACCUMULATIONS IN ANY PERSISTENT SNOW SHOWERS OVER THE HIGH
TERRAIN. USED A BLEND OF MAV/MET MOS WHICH BRINGS TEMPERATURES IN
THE MOUNTAINS TO BELOW FREEZING BY FRIDAY MORNING.
MODELS ARE IN DISAGREEMENT BY LATE IN THE DAY ON FRIDAY AS TO
WHETHER A WAVE OF LOW PRESSURE WILL RIDE UP THE FRONT AND SOUTH OF
NEW ENGLAND OR NOT. CURRENTLY...THE NAM IS MOST AGRESSIVE WITH THE
NORTHERN PROXIMITY OF PRECIPITATION...WHICH LEADS US TO THE LONG
RANGE PORTION OF THE FORECAST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
FRI NIGHT A WEAK WAVE OF LOW PRES WILL MOVE E ALONG A STALLED
FRONT LOCATED S OF NEW ENGL. SRN AREAS OF ME/NH WILL BE ON THE NRN
FRINGE OF THE PCPN SHIELD SO SOME LGT PCPN IS EXPECTED. THE PCPN
SHOULD PRODUCE PSBLY A FEW INCHES OF SNOW OVER SRN AREAS AS ANY
MIXED PCPN GRDLY CHANGES TO SNOW AS CAA OCCURS FRI NIGHT. BY SAT
MRNG SKIES CLEAR AS HIGH PRES BUILDS ACROSS THE REGION. HIGH PRES
BECOMES CENTERED OVER THE REGION SUN ALLOWING ANOTHER NICE DAY.
SUN NIGHT THE SFC/UPR RDG AXIS OVR NEW ENGL MOVES EWD ALLOWING A
MOIST SWLY FLOW TO DEVELOP AS A BROAD WAA PATTERN DEVELOPS AND
MOVES EWD INTO THE REGION BY MON MORNING. MODELS IN GENERAL
AGREEMENT THAT CONDS WILL BE COLD ENOUGH FOR SNOW AND SOME ACCUMS
EXPECTED AT THE ONSET MON MRNG BEFORE CHANGING OVER TO A MIX AND
THEN RAIN FROM S-N DURING THE DAY. BY MON NIGHT SYSTEM RAPIDLY
EXITS AND CLEARING EXPECTED AS A STRONG COLD FRONT MOVES THROUGH
THE REGION LATE IN THE SYSTEMS WAKE. TUES AND WED MUCH COLDER
TEMPS EXPECTED WITH BELOW NORMAL TEMPS EXPECTED.
ACCEPTED TIMING AND POPS OF SUPERBLEND GUID FOR DAYS 4-7.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
SHORT TERM...CONDITIONS GRADUALLY DETERIORATE THIS MORNING WITH LOW
CLOUDS AND POSSIBLY FOG/DRIZZLE MOVE IN. THIS COULD LEAD TO AN
EXTENDED PERIOD OF IFR OR LIFR CONDITIONS THROUGH TONIGHT...BEFORE
SLOWLY IMPROVING TO MVFR CONDITIONS ON FRIDAY.
LONG TERM...
FRI NIGHT IFR CONDS IN SNW OR MIXED PCPN OVER SRN AREAS WHILE NRN
AND CNTRL AREAS MAILY VFR. ON SAT CONDS BECOME VFR ACROSS ALL
AREAS AND CONTINUE THRU SUNDAY. THE NEXT SYSTEM APPROACHES SUN
NIGHT AND MON LOWERING CONDS TO IFR/LIFR ACROSS ALL AREAS.
&&
.MARINE...
SHORT TERM...SOUTHERLY FLOW TODAY WILL GRADUALLY BUILD 3 TO 5 FOOT
WAVES WITH TIME. WILL ISSUES SCA FOR SEAS...WHICH WILL CARRY ON
INTO FRIDAY. THIS IS FOR THE OUTER WATERS ONLY.
LONG TERM...
NO FLAGS FRI NIGHT AND SAT. NW WINDS MAY APPROACH SCA CONDS SUN.
ON MON AN INCRG E FLOW WILL PRODUCE SCA CONDS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 PM THIS
AFTERNOON TO 4 PM EST FRIDAY FOR ANZ150-152-154.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1037 AM EST THU DEC 5 2013
.UPDATE...
ISSUED AT 1036 AM EST THU DEC 5 2013
...LAKE EFFECT SNOW WARNING NOW UP FOR NORTHERN HOUGHTON COUNTY...
SIGNIFICANT LK EFFECT AND BLOWING SNOW HAS DEVELOPED OVER THE
KEWEENAW. VIS SATELLITE SHOWS TYPICAL ENHANCED BAND OF SNOW
DEVELOPING OFF THE TIP OF BAYFIELD PENINSULA STREAMING INTO THE
VCNTY OF HOUGHTON AND HANCOCK. THINK THIS SNOW BAND RECEIVED
INITIAL BOOST FROM FORCING MOVING ACROSS BRINGING LGT SNOW TO
REST OF WESTERN UPR MICHIGAN. OVERWATER INSTABILITY AND DEPTH OF
LAKE CONVECTIVE LAYER INCREASE THROUGH THE DAY SO THE FAVORABLE
LAKE EFFECT SETUP WILL ONLY BECOME MORE SO THROUGH THE AFTN. EXPECT
THE HEAVY LK EFFECT SNOW TO PERSIST BEFORE SHIFTING/RE-ORIENTING
LATER THIS AFTN INTO EARLY THIS EVENING AS SECONDARY TROUGH MOVING
THROUGH VEERS WINDS TO MORE NW...LIMITING THE PERSISTENT CONVERGENCE
AREA. BASED ON CURRENT TRENDS AND HIGH RES MODEL OUTPUT FOR REST OF
DAY AND WINDS UPSTREAM...ISSUED A LAKE EFFECT SNOW WARNING FOR
NORTHERN HOUGHTON COUNTY AS THAT IS WHERE THE HEAVIER BAND OF SNOW
WILL OCCUR THROUGH THE DAY.
TOTAL SNOW AMOUNTS MAY EXCEED 10 INCHES IF THE BAND STAYS PUT...BUT
THAT IS ALWAYS A CHALLENGE TO SAY IF THAT WILL OCCUR. SNOW RATES
WITHIN THE HEAVIER SNOW BAND WILL BE OVER 1 INCH PER HOUR. SNOW WILL
BE HARD TO MEASURE DUE TO STRONG WINDS BUT THAT ALSO RESULTS IN VERY
POOR VSBY AS SEEN ON WEB CAMS THIS MORNING AND CMX BEING LESS THAN
1/4SM AT TIMES.
WARNING WILL GO THROUGH 03Z WHEN SHIFTING WINDS SHOULD RE-ORIENT THE
HEAVIER SNOW AREAS. VERY LIKELY THIS MAY OCCUR EARLIER THAN 03Z BUT
WANTED TO GIVE EXTRA WIGGLE ROOM AT THE END OF THE WARNING. BEYOND
03Z THE LK EFFECT ADVY KICKS BACK IN. NO CHANGES TO KEWEENAW COUNTY
ADVY AS HEAVIER SNOW SHOWERS WILL FOCUS MORE TO THE SOUTH OF THAT
AREA TODAY. OTHERWISE...BOOSTED POPS FOR NEXT FEW HOURS AWAY FM
KEWEENAW AS LGT SNOW SHOWERS MOVE ACROSS WITH SHALLOW DEPTH
DISTURBANCE. EVENTUALLY THOUGH...EXPECT SNOW TO TAPER OFF/END
LEAVING JUST PERSISTENT FALLING TEMPS AND LOWERING WIND
CHILLS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 504 AM EST THU DEC 5 2013
CONTINUED THE LAKE EFFECT SNOW ADVISORY FOR THE KEWEENAW WHICH WAS
EXTENDED THROUGH SUNDAY MORNING.
RADAR AND SURFACE OBSERVATIONS THIS MORNING ARE ONLY SHOWING A FEW
LINGERING SNOW SHOWERS OVER CENTRAL PORTIONS OF THE UPPER PENINSULA
WITH WINDS BEGINNING TO GUST OUT OF THE SOUTHWEST TO NEARLY 30MPH.
ALSO A WIDE RANGE OF TEMPERATURES ARE BEING DISPLAYED ACROSS THE CWA
WITH IWD AROUND 19F WILE NEWBERRY IS AROUND 36F. THE COOL DOWN IS
EXPECTED TO CONTINUE THROUGH THE DAY.
TODAY AND TONIGHT....LOW PRESSURE CENTERED OVER UPPER MICHIGAN AND
LAKE SUPERIOR EARLY THIS MORNING...WHILE A COLD FRONT WHILE A COLD
FRONT STRETCHES SOUTH AND WESTWARD FROM NORTH CENTRAL WI TO
SOUTHEAST MN AS OF 06Z. THE LOW IS EXPECTED TO CONTINUE
NORTHEASTWARD...PUSHING INTO ONTARIO BY DAY BREAK TODAY. AS THIS
HAPPENS THE COLD FRONT WILL HAVE PASSED THROUGH ALLOWING
TEMPERATURES TO DROP SIGNIFICANTLY ACROSS THE CWA. THIS WILL ALLOW
ANY LIQUID REMAINING ON THE ROADWAYS TO REFREEZE ALLOWING TRAVEL TO
CONTINUE TO BE SLIPPERY ONCE AGAIN...THEREFORE...HAVE ISSUED A SPS
TO DRAW ATTENTION TO THIS POTENTIAL HAZARD. THE POSITIVE SIDE OF
THIS FORECAST PERIOD IS THAT THE MIXED PRECIPITATION HAS MOVED OUT
OF THE AREA...LEAVING TEMPERATURES ALOFT COLD ENOUGH TO KEEP
PRECIPITATION IN THE FORM OF SNOW AS THE UPPER LEVEL TROUGH
ASSOCIATED WITH THE SURFACE LOW PUSHES OVERHEAD. FOR THE
DETAILS...WINDS WILL BECOME FAIRLY STRONG OUT OF THE WEST AS THE
SURFACE CONTINUES LIFTS NORTHEASTWARD FROM NORTHERN LAKE SUPERIOR AS
OF 12Z/05 TO NEAR JAMES BAY BY 18Z/05...WHERE IT WILL BECOME NEARLY
STATIONARY.
WITH THE COLD AIR ADVECTION ACROSS THE RELATIVELY WARM WATERS OF
LAKES SUPERIOR IN THE WAKE OF THE LOW...LAKE EFFECT SNOW WILL BECOME
A CONCERN...ESPECIALLY FOR WESTERLY WIND FAVORED SNOW BELTS OF THE
UPPER PENINSULA. AT 850MB THE COLDER TEMPERATURES REALLY START TO
BUILD INTO THE AREA BY 12Z/05 WITH MUCH OF THE WESTERN HALF OF THE
U.P. UNDER -10C TO -14C 850MB TEMPS. THIS WILL AGAIN BE FAVORABLE
FOR LAKE EFFECT SNOW DEVELOPMENT AS LAKE SURFACE TEMPERATURES ARE
CURRENTLY RUNNING AROUND 4C TO 5C. TEMPERATURE INVERSION HEIGHTS
AROUND 12Z ARE PROGGED TO BE AROUND 7KFT WITH MOISTURE AND LIFT
BEGINNING TO BE COLLOCATED IN THE FAVORED DGZ...MAINLY OVER THE
KEWEENAW PENINSULA. EVEN COLDER TEMPERATURES ARE EXPECTED TO PUSH IN
AT 850MB BY EARLY AFTERNOON AROUND 18Z WITH 850MB TEMPERATURES
RANGING FROM -14C OVER THE EAST TO -17 OVER THE WEST AND INVERSION
HEIGHTS LIFT TO AROUND 8KFT. THIS HELPS TO PLACE A GREATER DEAL OF
MOISTURE AN FORCING IN THE DGZ...ALLOWING FOR BETTER SNOW GROWTH
OVER THE KEWEENAW PENINSULA. REALLY NOT MANY CHANGES OCCUR FROM
18Z/05 THROUGH 06Z/06...EXCEPT FOR EVEN COLDER AIR PRESSES INTO THE
UPPER PENINSULA AT 850MB...WITH TEMPERATURES AT THAT LEVEL DROPPING
TO -20C OVER THE WESTERN U.P. SLIGHTLY DRYER AIR BUILDS IN ALOFT BY
06Z WHICH WILL LIKELY HELP TO REDUCE THE INTENSITY OF THE LAKE
EFFECT SNOW ACROSS THE KEWEENAW.
AWAY FROM THE KEWEENAW PENINSULA...THE MAIN ISSUE DURING THIS ENTIRE
TIME FRAME WILL BE MUCH COLDER TEMPERATURES BUILDING INTO THE
REGION. THE THICK CLOUD BANK THAT HAS LINGERED OVER MUCH OF THE AREA
OVER THE PAST COUPLE OF DAYS WILL TRY TO FINALLY BREAK UP...MAINLY
AWAY FROM LAKE SUPERIOR. THIS CLEARING ALONG WITH THE AFOREMENTIONED
COLDER 850MB TEMPERATURES WILL ALLOW OVERNIGHT LOWS TO DROP INTO THE
SINGLE DIGITS ABOVE ZERO OVER MUCH OF THE U.P. WITH THE INLAND WEST
AREAS POSSIBLY DROPPING INTO SINGLE DIGITS BELOW ZERO. THESE BELOW
ZERO TEMPERATURES COUPLED WITH WEST WINDS CLOSE TO 10 MPH OVERNIGHT
WILL MAKE WIND CHILL READINGS FALL TO 15 TO 20 BELOW ZERO. THIS
WOULD BE MARGINAL FOR A WIND CHILL ADVISORY...BUT THIS MAY BE NEEDED
BY THE AFTERNOON UPDATE.
ALSO...AWAY FROM THE KEWEENAW DECIDED TO ISSUE A GALE WARNING FOR
NORTHWESTERN LAKE MICHIGAN AS TIGHT PRESSURE GRADIENT BUILDS OVER
THE AREA ALONG WITH CAA ALLOWING STRONGER WINDS ALOFT TO MIX DOWN TO
THE RELATIVELY WARM SURFACE OF THE LAKE. RUC ANALYSIS SHOWS THE
POTENTIAL FOR 38KT WINDS TO MIX DOWN TO THE SURFACE OF THE LAKE.
ALREADY THIS MORNING THERE WERE A COUPLE OF OBS COMING IN WITH GUSTS
TO 32KTS...WITH THESE GUSTS LIKELY TO INTENSIFY THROUGH THIS
AFTERNOON.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 504 AM EST THU DEC 5 2013
MAIN FCST CONCERNS IN THE LONG TERM INCLUDE TEMPS/LES MAINLY IN THE
W-NW SN BELTS AND THE POTENTIAL FOR ANOTHER LARGER SCALE SN EVENT
EARLY NEXT WEEK. OVERALL TEMPS WL RUN WELL BLO NORMAL MOST OF THE
LONGER TERM WITH ARCTIC AIRMASSES DOMINATING.
FRI INTO SAT...AS THE LO TO THE NE DRIFTS SLOWLY INTO QUEBEC AND
ARCTIC HI PRES SLIDES FM WRN CANADA INTO THE NRN PLAINS...THE STEADY
FLOW OF VERY COLD AIR IS PROGGED TO GRDLY VEER TOWARD THE WNW AND
DIMINISH WITH TIME AS H85 TEMPS FALL SLOWLY TO ARND -17C OVER THE E
AND -21C OVER THE W BY 12Z SAT. THIS TYPICAL WINTER WX REGIME WL
FAVOR NEARLY CONTINUOUS LES IN THE FAVORED SN BELTS. A SHRTWV
TRACKING EWD THRU SRN ONTARIO/NRN LK SUP ON FRI NGT AND ACCOMPANYING
DEEPER MSTR MAY RESULT IN SOME ENHANCEMENT TO THE LES. ALTHOUGH THE
WINDS/BLSN WL BE DIMINISHING GRDLY...EXPECT LES/WINTER WX ADVYS TO
BE IN PLACE FOR THE FAVORED LES BELTS WITH FAVORABLE ALIGNMENT OF
THE LLVL OMEGA WITHIN THE DGZ. WENT HIER THAN MODEL CONSENSUS POPS
FOR LES IN THE FAVORED SN BELTS...USING CLIMATOLOGY GRIDS TO
EVALUATE THE POPS. AS THE LLVL WINDS DIMINISH...LAND BREEZE CNVGC
MAY PLAY A MORE IMPORTANT ROLE IN ENHANCING THE LES BANDS IN SOME
PLACES...WITH AT LEAST LOCALLY HEAVIER SN FALL APRCHG WARNING
CRITERIA. THIS POTENTIAL APPEARS GREATEST NEAR LK SUP E OF GRAND
MARAIS ON FRI NGT. SN/WATER RATIOS WL ALSO LIKELY BE MORE FVRBL FOR
LARGER FLAKES AS THE FLAKE FRACTURING DIMINISHES WITH THE WEAKENING
WINDS. AWAY FM THE FAVORED SN BELTS...THE WX DURING THIS TIME WL BE
VERY COLD BUT DRY. SUB ZERO MIN TEMPS WITH DAYTIME TEMPS STRUGGLING
TO RISE ABV 10F WL THE RULE OVER THE INTERIOR W HALF WITHIN THE LESS
MODIFIED ARCTIC AIR.
SAT NGT/SUN...THE SLOW EWD PUSH OF THE ARCTIC HI CENTER FM THE NRN
PLAINS THRU THE GREAT LKS/SLOWLY BACKING WINDS TO WSW ON SUN WL
CAUSE THE LES TO DIMINISH. THESE SHSN WL LINGER THE LONGEST OVER THE
KEWEENAW...AND EXTNENDED LES ADVY FOR THAT AREA UNTIL 12Z SUN.
DEPENDING ON HOW QUICKLY WAD CLDS SPILL INTO THE UPR LKS ON SUN TO
THE E OF A DEEPENING TROF IN THE PLAINS...TEMPS AT SOME PLACES OVER
THE INTERIOR ON EARLY SUN MRNG MAY FALL INTO THE TEENS BLO ZERO WITH
LGT WINDS UNDER THE ARRIVING SFC HI CENTER.
EXTENDED...NEXT LARGER SCALE PCPN EPISODE IS LIKELY TO ARRIVE ON SUN
NGT INTO EARLY MON. SOME OF THE LONGER TERM MODELS WERE SHOWING A
PHASING OF THE ARCTIC/POLAR BRANCHES WITH A DEEPER SFC LO TRACKING
THRU THE WCENTRAL GREAT LKS. IF THIS SCENARIO WERE TO VERIFY...A
WDSPRD ADVY SN WL BE PSBL OVER MUCH OF THE CWA. BUT THE MORE RECENT
LONGER TERM GUIDANCE APPEARS TO BE SHIFTING TOWARD LESS PHASING/A
WEAKER SFC LO THAT WOULD CAUSE JUST A FEW INCHES...MAINLY OVER THE E
CLOSER TO LO TRACK THRU LOWER MI. SINCE THE TREND HAS BEEN FOR A
WEAKER LO...GUIDANCE IS ALSO INDICATING THE AIRMASS FOLLOWING INTO
THE UPR LKS FOR LATER MON INTO TUE MAY NOT BE AS COLD AS PREVIOUSLY
INDICATED...WITH H85 TEMPS DOWN TO -25C INSTEAD OF -28C OR EVEN
-30C. STILL...LES WOULD BE A GOOD BET IN THE NW WIND SNOW BELTS. A
NUMBER OF THE LONGER TERM MODELS INDICATE A CLIPPER LO PRES MIGHT
TRACK THRU THE UPR LKS ON TUE AND BRING ANOTHER PERIOD OF MORE
WDSPRD -SN. THE CHILLY NW FLOW BTWN THE DEPARTING CLIPPER LO IN
ONTARIO AND HI PRES SINKING INTO THE CENTRAL CONUS WL THEN BRING
ANOTHER ROUND OF LES IN THE FAVORED SN BELTS. FINALLY...SOME OF THE
EXTENDED GUIDANCE IS HINTING THE UPR FLOW WL TREND MORE ZONAL LATER
NEXT WEEK AND BRING A MODERATION TO THE ARCTIC CHILL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 645 AM EST THU DEC 5 2013
A STRONG PRESSURE GRADIENT BEHIND THE DEPARTING LOW PRESSURE SYSTEM
WILL CAUSE WINDS TO BE FAIRLY GUSTY TODAY INTO TONIGHT FROM THE WEST
AT EACH OF THE TAF SITES. CMX AND IWD WILL LIKELY SEE SOME OF THE
STRONGER GUSTS...APPROACHING 40KTS AT TIMES. VISIBILITY SHOULD NOT
BE AN ISSUE FOR IWD OR SAW THROUGH THIS TAF PERIOD. CEILINGS WILL
LIKELY LINGER AT OR AROUND MVFR TO IFR AT IWD AND CMX AS LAKE EFFECT
CLOUD COVER BUILDS IN. KSAW WILL SEE CEILINGS IMPROVE THROUGH THE
DAY...LIKELY BECOMING VFR BY MID AFTERNOON. AS FAR AS VISIBILITY
GOES...THE BIGGEST ISSUE WILL BE AT CMX AS LAKE EFFECT SNOW SHOWERS
DEVELOP THROUGH THE MID TO LATE MORNING HOURS AND LINGERS INTO THE
NIGHT TIME. KEPT THE GOING VISIBILITY OF 1SM AT CMX AS BLSN MAY BE
INTRODUCED WITH ANY FRESH SNOW THAT DOES OCCUR...COULD SEE VISIBILITY
FALLING LOWER THAN 1SM AT TIMES DURING THE HEAVIER LAKE EFFECT
BANDS...BUT ITS A BIT EARLY TO PIN POINT THE BEST TIME FOR THIS TO
OCCUR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 504 AM EST THU DEC 5 2013
EXPECT W GALES AS HI AS 40-45 KTS TO DEVELOP OVER LAKE SUPERIOR
TODAY AND CONTINUE INTO TONIGHT WITH SHARPENING PRES GRADIENT ON THE
SW FLANK OF LO PRES MOVING NE THRU ONTARIO. FREEZING SPRAY WILL ALSO
DEVELOP AS VERY COLD ARCTIC AIR SPILLS OUT OVER THE LAKE. THERE MAY
BE POCKETS OF HEAVY FREEZING SPRAY TONIGHT. THE W GALES WILL THEN
SLOWLY DIMINISH W-E LATE TONIGHT/FRI AS THE PRES GRADIENT SLOWLY
SLACKENS WITH THE SLOW APPROACH OF HI PRES FROM THE NORTHERN PLAINS.
WINDS WILL TURN TO THE S-SW ON SUN AND DIMINISH UNDER 15 KTS WITH
THE PASSAGE OF THE HI PRES TO THE E. A LO PRES SYSTEM MOVING NE THRU
LOWER MI ON SU NIGHT WILL FOLLOW THE DEPARTING HI. NW GALES AND MORE
FREEZING SPRAY WILL THEN DEVELOP ON MON AS ANOTHER ARCTIC AIRMASS
INVADES THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST
SUNDAY FOR MIZ003.
LAKE EFFECT SNOW WARNING UNTIL 10 PM EST THIS EVENING FOR MIZ003.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST SUNDAY FOR MIZ001.
LAKE SUPERIOR...
GALE WARNING UNTIL 11 AM EST FRIDAY FOR LSZ264>267.
GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ162.
GALE WARNING UNTIL 4 AM EST FRIDAY FOR LSZ263.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ246>248-250-251.
GALE WARNING UNTIL 1 AM EST /MIDNIGHT CST/ FRIDAY FOR LSZ241>245.
LAKE MICHIGAN...
GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LMZ221-248-250.
&&
$$
UPDATE...JLA
SHORT TERM...KEC
LONG TERM...KC
AVIATION...KEC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
647 AM EST THU DEC 5 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 504 AM EST THU DEC 5 2013
CONTINUED THE LAKE EFFECT SNOW ADVISORY FOR THE KEWEENAW WHICH WAS
EXTENDED THROUGH SUNDAY MORNING.
RADAR AND SURFACE OBSERVATIONS THIS MORNING ARE ONLY SHOWING A FEW
LINGERING SNOW SHOWERS OVER CENTRAL PORTIONS OF THE UPPER PENINSULA
WITH WINDS BEGINNING TO GUST OUT OF THE SOUTHWEST TO NEARLY 30MPH.
ALSO A WIDE RANGE OF TEMPERATURES ARE BEING DISPLAYED ACROSS THE CWA
WITH IWD AROUND 19F WILE NEWBERRY IS AROUND 36F. THE COOL DOWN IS
EXPECTED TO CONTINUE THROUGH THE DAY.
TODAY AND TONIGHT....LOW PRESSURE CENTERED OVER UPPER MICHIGAN AND
LAKE SUPERIOR EARLY THIS MORNING...WHILE A COLD FRONT WHILE A COLD
FRONT STRETCHES SOUTH AND WESTWARD FROM NORTH CENTRAL WI TO
SOUTHEAST MN AS OF 06Z. THE LOW IS EXPECTED TO CONTINUE
NORTHEASTWARD...PUSHING INTO ONTARIO BY DAY BREAK TODAY. AS THIS
HAPPENS THE COLD FRONT WILL HAVE PASSED THROUGH ALLOWING
TEMPERATURES TO DROP SIGNIFICANTLY ACROSS THE CWA. THIS WILL ALLOW
ANY LIQUID REMAINING ON THE ROADWAYS TO REFREEZE ALLOWING TRAVEL TO
CONTINUE TO BE SLIPPERY ONCE AGAIN...THEREFORE...HAVE ISSUED A SPS
TO DRAW ATTENTION TO THIS POTENTIAL HAZARD. THE POSITIVE SIDE OF
THIS FORECAST PERIOD IS THAT THE MIXED PRECIPITATION HAS MOVED OUT
OF THE AREA...LEAVING TEMPERATURES ALOFT COLD ENOUGH TO KEEP
PRECIPITATION IN THE FORM OF SNOW AS THE UPPER LEVEL TROUGH
ASSOCIATED WITH THE SURFACE LOW PUSHES OVERHEAD. FOR THE
DETAILS...WINDS WILL BECOME FAIRLY STRONG OUT OF THE WEST AS THE
SURFACE CONTINUES LIFTS NORTHEASTWARD FROM NORTHERN LAKE SUPERIOR AS
OF 12Z/05 TO NEAR JAMES BAY BY 18Z/05...WHERE IT WILL BECOME NEARLY
STATIONARY.
WITH THE COLD AIR ADVECTION ACROSS THE RELATIVELY WARM WATERS OF
LAKES SUPERIOR IN THE WAKE OF THE LOW...LAKE EFFECT SNOW WILL BECOME
A CONCERN...ESPECIALLY FOR WESTERLY WIND FAVORED SNOW BELTS OF THE
UPPER PENINSULA. AT 850MB THE COLDER TEMPERATURES REALLY START TO
BUILD INTO THE AREA BY 12Z/05 WITH MUCH OF THE WESTERN HALF OF THE
U.P. UNDER -10C TO -14C 850MB TEMPS. THIS WILL AGAIN BE FAVORABLE
FOR LAKE EFFECT SNOW DEVELOPMENT AS LAKE SURFACE TEMPERATURES ARE
CURRENTLY RUNNING AROUND 4C TO 5C. TEMPERATURE INVERSION HEIGHTS
AROUND 12Z ARE PROGGED TO BE AROUND 7KFT WITH MOISTURE AND LIFT
BEGINNING TO BE COLLOCATED IN THE FAVORED DGZ...MAINLY OVER THE
KEWEENAW PENINSULA. EVEN COLDER TEMPERATURES ARE EXPECTED TO PUSH IN
AT 850MB BY EARLY AFTERNOON AROUND 18Z WITH 850MB TEMPERATURES
RANGING FROM -14C OVER THE EAST TO -17 OVER THE WEST AND INVERSION
HEIGHTS LIFT TO AROUND 8KFT. THIS HELPS TO PLACE A GREATER DEAL OF
MOISTURE AN FORCING IN THE DGZ...ALLOWING FOR BETTER SNOW GROWTH
OVER THE KEWEENAW PENINSULA. REALLY NOT MANY CHANGES OCCUR FROM
18Z/05 THROUGH 06Z/06...EXCEPT FOR EVEN COLDER AIR PRESSES INTO THE
UPPER PENINSULA AT 850MB...WITH TEMPERATURES AT THAT LEVEL DROPPING
TO -20C OVER THE WESTERN U.P. SLIGHTLY DRYER AIR BUILDS IN ALOFT BY
06Z WHICH WILL LIKELY HELP TO REDUCE THE INTENSITY OF THE LAKE
EFFECT SNOW ACROSS THE KEWEENAW.
AWAY FROM THE KEWEENAW PENINSULA...THE MAIN ISSUE DURING THIS ENTIRE
TIME FRAME WILL BE MUCH COLDER TEMPERATURES BUILDING INTO THE
REGION. THE THICK CLOUD BANK THAT HAS LINGERED OVER MUCH OF THE AREA
OVER THE PAST COUPLE OF DAYS WILL TRY TO FINALLY BREAK UP...MAINLY
AWAY FROM LAKE SUPERIOR. THIS CLEARING ALONG WITH THE AFOREMENTIONED
COLDER 850MB TEMPERATURES WILL ALLOW OVERNIGHT LOWS TO DROP INTO THE
SINGLE DIGITS ABOVE ZERO OVER MUCH OF THE U.P. WITH THE INLAND WEST
AREAS POSSIBLY DROPPING INTO SINGLE DIGITS BELOW ZERO. THESE BELOW
ZERO TEMPERATURES COUPLED WITH WEST WINDS CLOSE TO 10 MPH OVERNIGHT
WILL MAKE WIND CHILL READINGS FALL TO 15 TO 20 BELOW ZERO. THIS
WOULD BE MARGINAL FOR A WIND CHILL ADVISORY...BUT THIS MAY BE NEEDED
BY THE AFTERNOON UPDATE.
ALSO...AWAY FROM THE KEWEENAW DECIDED TO ISSUE A GALE WARNING FOR
NORTHWESTERN LAKE MICHIGAN AS TIGHT PRESSURE GRADIENT BUILDS OVER
THE AREA ALONG WITH CAA ALLOWING STRONGER WINDS ALOFT TO MIX DOWN TO
THE RELATIVELY WARM SURFACE OF THE LAKE. RUC ANALYSIS SHOWS THE
POTENTIAL FOR 38KT WINDS TO MIX DOWN TO THE SURFACE OF THE LAKE.
ALREADY THIS MORNING THERE WERE A COUPLE OF OBS COMING IN WITH GUSTS
TO 32KTS...WITH THESE GUSTS LIKELY TO INTENSIFY THROUGH THIS
AFTERNOON.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 504 AM EST THU DEC 5 2013
MAIN FCST CONCERNS IN THE LONG TERM INCLUDE TEMPS/LES MAINLY IN THE
W-NW SN BELTS AND THE POTENTIAL FOR ANOTHER LARGER SCALE SN EVENT
EARLY NEXT WEEK. OVERALL TEMPS WL RUN WELL BLO NORMAL MOST OF THE
LONGER TERM WITH ARCTIC AIRMASSES DOMINATING.
FRI INTO SAT...AS THE LO TO THE NE DRIFTS SLOWLY INTO QUEBEC AND
ARCTIC HI PRES SLIDES FM WRN CANADA INTO THE NRN PLAINS...THE STEADY
FLOW OF VERY COLD AIR IS PROGGED TO GRDLY VEER TOWARD THE WNW AND
DIMINISH WITH TIME AS H85 TEMPS FALL SLOWLY TO ARND -17C OVER THE E
AND -21C OVER THE W BY 12Z SAT. THIS TYPICAL WINTER WX REGIME WL
FAVOR NEARLY CONTINUOUS LES IN THE FAVORED SN BELTS. A SHRTWV
TRACKING EWD THRU SRN ONTARIO/NRN LK SUP ON FRI NGT AND ACCOMPANYING
DEEPER MSTR MAY RESULT IN SOME ENHANCEMENT TO THE LES. ALTHOUGH THE
WINDS/BLSN WL BE DIMINISHING GRDLY...EXPECT LES/WINTER WX ADVYS TO
BE IN PLACE FOR THE FAVORED LES BELTS WITH FAVORABLE ALIGNMENT OF
THE LLVL OMEGA WITHIN THE DGZ. WENT HIER THAN MODEL CONSENSUS POPS
FOR LES IN THE FAVORED SN BELTS...USING CLIMATOLOGY GRIDS TO
EVALUATE THE POPS. AS THE LLVL WINDS DIMINISH...LAND BREEZE CNVGC
MAY PLAY A MORE IMPORTANT ROLE IN ENHANCING THE LES BANDS IN SOME
PLACES...WITH AT LEAST LOCALLY HEAVIER SN FALL APRCHG WARNING
CRITERIA. THIS POTENTIAL APPEARS GREATEST NEAR LK SUP E OF GRAND
MARAIS ON FRI NGT. SN/WATER RATIOS WL ALSO LIKELY BE MORE FVRBL FOR
LARGER FLAKES AS THE FLAKE FRACTURING DIMINISHES WITH THE WEAKENING
WINDS. AWAY FM THE FAVORED SN BELTS...THE WX DURING THIS TIME WL BE
VERY COLD BUT DRY. SUB ZERO MIN TEMPS WITH DAYTIME TEMPS STRUGGLING
TO RISE ABV 10F WL THE RULE OVER THE INTERIOR W HALF WITHIN THE LESS
MODIFIED ARCTIC AIR.
SAT NGT/SUN...THE SLOW EWD PUSH OF THE ARCTIC HI CENTER FM THE NRN
PLAINS THRU THE GREAT LKS/SLOWLY BACKING WINDS TO WSW ON SUN WL
CAUSE THE LES TO DIMINISH. THESE SHSN WL LINGER THE LONGEST OVER THE
KEWEENAW...AND EXTNENDED LES ADVY FOR THAT AREA UNTIL 12Z SUN.
DEPENDING ON HOW QUICKLY WAD CLDS SPILL INTO THE UPR LKS ON SUN TO
THE E OF A DEEPENING TROF IN THE PLAINS...TEMPS AT SOME PLACES OVER
THE INTERIOR ON EARLY SUN MRNG MAY FALL INTO THE TEENS BLO ZERO WITH
LGT WINDS UNDER THE ARRIVING SFC HI CENTER.
EXTENDED...NEXT LARGER SCALE PCPN EPISODE IS LIKELY TO ARRIVE ON SUN
NGT INTO EARLY MON. SOME OF THE LONGER TERM MODELS WERE SHOWING A
PHASING OF THE ARCTIC/POLAR BRANCHES WITH A DEEPER SFC LO TRACKING
THRU THE WCENTRAL GREAT LKS. IF THIS SCENARIO WERE TO VERIFY...A
WDSPRD ADVY SN WL BE PSBL OVER MUCH OF THE CWA. BUT THE MORE RECENT
LONGER TERM GUIDANCE APPEARS TO BE SHIFTING TOWARD LESS PHASING/A
WEAKER SFC LO THAT WOULD CAUSE JUST A FEW INCHES...MAINLY OVER THE E
CLOSER TO LO TRACK THRU LOWER MI. SINCE THE TREND HAS BEEN FOR A
WEAKER LO...GUIDANCE IS ALSO INDICATING THE AIRMASS FOLLOWING INTO
THE UPR LKS FOR LATER MON INTO TUE MAY NOT BE AS COLD AS PREVIOUSLY
INDICATED...WITH H85 TEMPS DOWN TO -25C INSTEAD OF -28C OR EVEN
-30C. STILL...LES WOULD BE A GOOD BET IN THE NW WIND SNOW BELTS. A
NUMBER OF THE LONGER TERM MODELS INDICATE A CLIPPER LO PRES MIGHT
TRACK THRU THE UPR LKS ON TUE AND BRING ANOTHER PERIOD OF MORE
WDSPRD -SN. THE CHILLY NW FLOW BTWN THE DEPARTING CLIPPER LO IN
ONTARIO AND HI PRES SINKING INTO THE CENTRAL CONUS WL THEN BRING
ANOTHER ROUND OF LES IN THE FAVORED SN BELTS. FINALLY...SOME OF THE
EXTENDED GUIDANCE IS HINTING THE UPR FLOW WL TREND MORE ZONAL LATER
NEXT WEEK AND BRING A MODERATION TO THE ARCTIC CHILL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 645 AM EST THU DEC 5 2013
A STRONG PRESSURE GRADIENT BEHIND THE DEPARTING LOW PRESSURE SYSTEM
WILL CAUSE WINDS TO BE FAIRLY GUSTY TODAY INTO TONIGHT FROM THE WEST
AT EACH OF THE TAF SITES. CMX AND IWD WILL LIKELY SEE SOME OF THE
STRONGER GUSTS...APPROACHING 40KTS AT TIMES. VISIBILITY SHOULD NOT
BE AN ISSUE FOR IWD OR SAW THROUGH THIS TAF PERIOD. CEILINGS WILL
LIKELY LINGER AT OR AROUND MVFR TO IFR AT IWD AND CMX AS LAKE EFFECT
CLOUD COVER BUILDS IN. KSAW WILL SEE CEILINGS IMPROVE THROUGH THE
DAY...LIKELY BECOMING VFR BY MID AFTERNOON. AS FAR AS VISIBILITY
GOES...THE BIGGEST ISSUE WILL BE AT CMX AS LAKE EFFECT SNOW SHOWERS
DEVELOP THROUGH THE MID TO LATE MORNING HOURS AND LINGERS INTO THE
NIGHT TIME. KEPT THE GOING VISIBILITY OF 1SM AT CMX AS BLSN MAY BE
INTRODUCED WITH ANY FRESH SNOW THAT DOES OCCUR...COULD SEE VISIBILITY
FALLING LOWER THAN 1SM AT TIMES DURING THE HEAVIER LAKE EFFECT
BANDS...BUT ITS A BIT EARLY TO PIN POINT THE BEST TIME FOR THIS TO
OCCUR. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 504 AM EST THU DEC 5 2013
EXPECT W GALES AS HI AS 40-45 KTS TO DEVELOP OVER LAKE SUPERIOR
TODAY AND CONTINUE INTO TONIGHT WITH SHARPENING PRES GRADIENT ON THE
SW FLANK OF LO PRES MOVING NE THRU ONTARIO. FREEZING SPRAY WILL ALSO
DEVELOP AS VERY COLD ARCTIC AIR SPILLS OUT OVER THE LAKE. THERE MAY
BE POCKETS OF HEAVY FREEZING SPRAY TONIGHT. THE W GALES WILL THEN
SLOWLY DIMINISH W-E LATE TONIGHT/FRI AS THE PRES GRADIENT SLOWLY
SLACKENS WITH THE SLOW APPROACH OF HI PRES FROM THE NORTHERN PLAINS.
WINDS WILL TURN TO THE S-SW ON SUN AND DIMINISH UNDER 15 KTS WITH
THE PASSAGE OF THE HI PRES TO THE E. A LO PRES SYSTEM MOVING NE THRU
LOWER MI ON SU NIGHT WILL FOLLOW THE DEPARTING HI. NW GALES AND MORE
FREEZING SPRAY WILL THEN DEVELOP ON MON AS ANOTHER ARCTIC AIRMASS
INVADES THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST SUNDAY FOR MIZ001-003.
LAKE SUPERIOR...
GALE WARNING UNTIL 11 AM EST FRIDAY FOR LSZ264>267.
GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ162.
GALE WARNING UNTIL 4 AM EST FRIDAY FOR LSZ263.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ246>248-250-251.
GALE WARNING UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR
LSZ241>245.
LAKE MICHIGAN...
GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LMZ221-248-250.
&&
$$
SHORT TERM...KEC
LONG TERM...KC
AVIATION...KEC
MARINE...KC
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
1247 PM MST THU DEC 5 2013
.UPDATE...UPDATED AVIATION DISCUSSION.
&&
.SYNOPSIS...
A LARGE AND COLD LOW PRESSURE SYSTEM WILL CONTINUE TO COVER THE
WESTERN STATES THROUGH EARLY NEXT WEEK. A COUPLE OF WEATHER
DISTURBANCES...ROTATING THROUGH THE LARGE WESTERN REGION
TROUGH...WILL BRING A CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW
LATER SATURDAY AND SATURDAY NIGHT. RATHER COLD NIGHT-TIME
TEMPERATURES ARE EXPECTED THROUGH MONDAY MORNING...WITH CLEAR SKIES
AND A WARMING TREND BY THE MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...
MID MORNING SATELLITE IMAGERY REVEALS A BROAD TROUGH ACROSS THE
WESTERN CONUS WITH A LARGE PLUME OF MOISTURE EXTENDING WELL INTO THE
CENTRAL PLAINS. YESTERDAYS STORM SYSTEM HAS SHIFTED EAST AND IS IN
THE PROCESS OF PRODUCING A WINTRY MIX OVER PARTS OF
TEXAS...OKLAHOMA...ARKANSAS...KANSAS AND MISSOURI AMONG OTHER
STATES. MEANWHILE SOUTH-CENTRAL ARIZONA AND SOUTHEAST CALIFORNIA ARE
LARGELY IN THE CLEAR THIS MORNING. ASIDE FROM A FEW LINGERING CLOUDS
ACROSS SOUTHERN GILA COUNTY AND SOME CLOUDS MAKING THEIR WAY OVER
THE COASTAL MOUNTAINS INTO IMPERIAL COUNTY...SKIES WERE CLEAR AS OF
16Z. TEMPS WERE GENERALLY IN THE UPPER 30S TO LOWER 40S ACROSS THE
LOWER DESERTS.
FOR TODAY...EXPECT CLEARING SKIES AND DRY WEATHER ACROSS MOST OF THE
AREA AS THE TROUGH SHIFTS EAST. THE CLOUDS ACROSS SOUTHEAST
CALIFORNIA WILL GRADUALLY THIN OUT LATER THIS AFTERNOON AND
EVENING...BUT THERE COULD BE AN ISOLATED SPRINKLE IN FAR SOUTHWEST
IMPERIAL COUNTY THROUGH LATE DAY. LOCAL WRFS AND HRRR GUIDANCE
SUGGEST AT LEAST SOME POTENTIAL FOR A ROGUE SHOWER IN THAT AREA BUT
COVERAGE WILL BE SPARSE AND POPS ARE ONLY IN THE 5-15 PERCENT RANGE.
HAVENT ADDRESSED TEMPERATURES FOR TONIGHT BUT INITIAL GUIDANCE
SUGGESTS THE FREEZE WARNING FOR MOST OF THE LOWER AZ DESERTS LOOKS
ON TRACK. GIVEN THE COLD START THIS MORNING AND THE POTENTIAL FOR
HIGHS TO ONLY REACH THE MID 50S THIS AFTERNOON...SHOULD BE FAIRLY
EASY TO DROP INTO THE LOWER 30S IN THE NORMALLY COLDER SPOTS TONIGHT.
FRIDAY...
FRIDAY WILL BE IN-BETWEEN SHORTWAVE TROFS...WITH ANOTHER DISTURBANCE
APPROACHING ON SATURDAY. THEREFORE MOSTLY CLEAR SKIES ARE EXPECTED
FRIDAY WITH MUCH BELOW NORMAL AFTERNOON TEMPERATURES.
SATURDAY AND SUNDAY...
THIS PERIOD WILL BE RATHER INTERESTING AND A LITTLE COMPLICATED.
ANOTHER SHORTWAVE TROF/DISTURBANCE...ROTATING AROUND THE FLOW
PATTERN OF THE MUCH LARGER WESTERN REGION LOW PRESSURE SYSTEM...
WILL APPROACH AZ LATER SATURDAY. DUE TO THE MASSIVELY COLD AIRMASS
OVER THE WESTERN REGION VERY LITTLE MOISTURE EXISTS IN QUANTITATIVE
TERMS. HOWEVER...BITTERLY COLD CANADIAN AIR WILL SPREAD OFF THE
WA...OR...AND NRN CA COASTS FRIDAY/FRIDAY NIGHT...GENERATING STRONG
LOW LEVEL THERMAL AND GEOSTROPHIC WINDS TO MECHANICALLY FORCE
RELATIVELY HIGH AMOUNTS OF BOUNDARY LAYER MOISTURE...AT AND BELOW
700 MB...INTO THE FORECAST AREA AHEAD OF THE DISTURBANCE SATURDAY
AND SATURDAY NIGHT.
THE PLUME OF LOW LEVEL MOISTURE WILL SPREAD INTO SOUTHEAST CA AND
PARTS OF SOUTHWEST AZ SATURDAY AFTERNOON...THEN INTO SOUTH CENTRAL
AZ SATURDAY NIGHT. DUE TO RATHER STRONG LOW/MID LEVEL WESTERLY WINDS
SATURDAY...RAIN SHADOW EFFECTS WILL HINDER PRECIP CHANCES IN THE
IMPERIAL VALLEY OF SOUTHEAST CA...BUT A VERY WINDY MORNING AND
AFTERNOON IS EXPECTED.
ALTHOUGH MOST OF THE MOISTURE WILL EXIST AT OR BELOW 700 MB...
TEMPERATURES AT THESE LEVELS WILL BE VERY COLD WITH MOISTURE LOCATED
IN THE ICE CRYSTAL/PRECIP GROWTH ZONES OF MINUS 10 DEG C AND COLDER.
COMPOUND THIS WITH 30 KNOTS 800/700 MB SOUTHWESTERLY UPSLOPE WINDS
IN SOUTHERN GILA COUNTY SATURDAY NIGHT...AND ABOUT 1 INCH OF SNOW IS
POSSIBLE AT 4500 FT...WITH 2-3 INCHES ABOVE 5000 FT. A CHANCE OF
SHOWERS IS ALSO POSSIBLE ON THE SOUTH CENTRAL AZ DESERTS INCLUDING
PHOENIX.
A FEW LINGERING SHOWERS WILL PERSIST SUNDAY MORNING BUT FOR THE MOST
PART DRIER AND COLDER AIR WILL SPREAD QUICKLY TO THE AREA. IN OTHER
WORDS CLEARING AND COLDER SUNDAY.
MONDAY AND TUESDAY...
MONDAY MORNING TEMPERATURES WILL BE COLD AGAIN...AND NEARLY SIMILAR
TO WHAT IS FORECAST TOMORROW OR FRIDAY MORNING. AGAIN...FREEZE
WARNING CRITERIA IS MARGINAL AND CERTAINLY NOTHING LIKE THE STRONG
COLD WAVES WEVE HAD IN THE RECENT PAST. OTHERWISE...MOSTLY CLEAR
SKIES ARE EXPECTED MONDAY AND TUESDAY WITH A WARMING TREND.
WEDNESDAY AND THURSDAY...
MOSTLY CLEAR WITH TEMPERATURES FINALLY APPROACHING NORMAL.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA...AND KSDL...AND
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA...INCLUDING KIPL AND KBLH...
MOSTLY CLEAR SKIES WITH FEW-SCT CU AROUND 10KFT...AND LIGHT WINDS
GENERALLY 10KT OR LESS EXPECTED AT ALL TAF SITES THROUGH AT LEAST
15Z FRIDAY MORNING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
ANOTHER LOW PRESSURE SYSTEM WILL MOVE THROUGH THE FORECAST AREA THIS
WEEKEND. BEST CHANCE FOR PRECIPITATION WILL BE SATURDAY NIGHT...
MAINLY OVER SOUTH-CENTRAL ARIZONA. AMOUNTS WILL BE LIGHT...LESS THAN
A TENTH OF AN INCH ON THE LOWER ELEVATIONS AND UP TO A QUARTER OF AN
INCH LIQUID EQUIVALENT OVER THE HIGHER MOUNTAINS. SNOW LEVELS WILL
BE 4000-4500 FEET SATURDAY...LOWERING SEVERAL HUNDRED FEET SATURDAY
NIGHT. ACCUMULATIONS OF 2-3 INCHES ABOVE 5000 FEET ARE POSSIBLE.
WINDY CONDITIONS CAN BE EXPECTED SATURDAY AFTERNOON AND EVENING OVER
SOUTHEAST CALIFORNIA...BREEZY ELSEWHERE. CLEARING CAN BE EXPECTED
SUNDAY. DRY CONDITIONS WITH NORTH AND NORTHEAST BREEZINESS CAN BE
EXPECTED MONDAY INTO WEDNESDAY...ESPECIALLY OVER THE LOWER COLORADO
RIVER VALLEY. AFTER A COLD START MONDAY...TEMPERATURES WILL SLOWLY
INCREASE.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...FREEZE WARNING IN EFFECT FOR THURSDAY NIGHT THROUGH FRIDAY
MORNING FOR AZZ021>024-026>028.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/VASQUEZ
AVIATION...MEYERS
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
919 AM MST THU DEC 5 2013
.SYNOPSIS...
A LARGE AND COLD LOW PRESSURE SYSTEM WILL CONTINUE TO COVER THE
WESTERN STATES THROUGH EARLY NEXT WEEK. A COUPLE OF WEATHER
DISTURBANCES...ROTATING THROUGH THE LARGE WESTERN REGION
TROUGH...WILL BRING A CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW
LATER SATURDAY AND SATURDAY NIGHT. RATHER COLD NIGHT-TIME
TEMPERATURES ARE EXPECTED THROUGH MONDAY MORNING...WITH CLEAR SKIES
AND A WARMING TREND BY THE MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...
MID MORNING SATELLITE IMAGERY REVEALS A BROAD TROUGH ACROSS THE
WESTERN CONUS WITH A LARGE PLUME OF MOISTURE EXTENDING WELL INTO THE
CENTRAL PLAINS. YESTERDAYS STORM SYSTEM HAS SHIFTED EAST AND IS IN
THE PROCESS OF PRODUCING A WINTRY MIX OVER PARTS OF
TEXAS...OKLAHOMA...ARKANSAS...KANSAS AND MISSOURI AMONG OTHER
STATES. MEANWHILE SOUTH-CENTRAL ARIZONA AND SOUTHEAST CALIFORNIA ARE
LARGELY IN THE CLEAR THIS MORNING. ASIDE FROM A FEW LINGERING CLOUDS
ACROSS SOUTHERN GILA COUNTY AND SOME CLOUDS MAKING THEIR WAY OVER
THE COASTAL MOUNTAINS INTO IMPERIAL COUNTY...SKIES WERE CLEAR AS OF
16Z. TEMPS WERE GENERALLY IN THE UPPER 30S TO LOWER 40S ACROSS THE
LOWER DESERTS.
FOR TODAY...EXPECT CLEARING SKIES AND DRY WEATHER ACROSS MOST OF THE
AREA AS THE TROUGH SHIFTS EAST. THE CLOUDS ACROSS SOUTHEAST
CALIFORNIA WILL GRADUALLY THIN OUT LATER THIS AFTERNOON AND
EVENING...BUT THERE COULD BE AN ISOLATED SPRINKLE IN FAR SOUTHWEST
IMPERIAL COUNTY THROUGH LATE DAY. LOCAL WRFS AND HRRR GUIDANCE
SUGGEST AT LEAST SOME POTENTIAL FOR A ROGUE SHOWER IN THAT AREA BUT
COVERAGE WILL BE SPARSE AND POPS ARE ONLY IN THE 5-15 PERCENT RANGE.
HAVENT ADDRESSED TEMPERATURES FOR TONIGHT BUT INITIAL GUIDANCE
SUGGESTS THE FREEZE WARNING FOR MOST OF THE LOWER AZ DESERTS LOOKS
ON TRACK. GIVEN THE COLD START THIS MORNING AND THE POTENTIAL FOR
HIGHS TO ONLY REACH THE MID 50S THIS AFTERNOON...SHOULD BE FAIRLY
EASY TO DROP INTO THE LOWER 30S IN THE NORMALLY COLDER SPOTS TONIGHT.
FRIDAY...
FRIDAY WILL BE IN-BETWEEN SHORTWAVE TROFS...WITH ANOTHER DISTURBANCE
APPROACHING ON SATURDAY. THEREFORE MOSTLY CLEAR SKIES ARE EXPECTED
FRIDAY WITH MUCH BELOW NORMAL AFTERNOON TEMPERATURES.
SATURDAY AND SUNDAY...
THIS PERIOD WILL BE RATHER INTERESTING AND A LITTLE COMPLICATED.
ANOTHER SHORTWAVE TROF/DISTURBANCE...ROTATING AROUND THE FLOW
PATTERN OF THE MUCH LARGER WESTERN REGION LOW PRESSURE SYSTEM...
WILL APPROACH AZ LATER SATURDAY. DUE TO THE MASSIVELY COLD AIRMASS
OVER THE WESTERN REGION VERY LITTLE MOISTURE EXISTS IN QUANTITATIVE
TERMS. HOWEVER...BITTERLY COLD CANADIAN AIR WILL SPREAD OFF THE
WA...OR...AND NRN CA COASTS FRIDAY/FRIDAY NIGHT...GENERATING STRONG
LOW LEVEL THERMAL AND GEOSTROPHIC WINDS TO MECHANICALLY FORCE
RELATIVELY HIGH AMOUNTS OF BOUNDARY LAYER MOISTURE...AT AND BELOW
700 MB...INTO THE FORECAST AREA AHEAD OF THE DISTURBANCE SATURDAY
AND SATURDAY NIGHT.
THE PLUME OF LOW LEVEL MOISTURE WILL SPREAD INTO SOUTHEAST CA AND
PARTS OF SOUTHWEST AZ SATURDAY AFTERNOON...THEN INTO SOUTH CENTRAL
AZ SATURDAY NIGHT. DUE TO RATHER STRONG LOW/MID LEVEL WESTERLY WINDS
SATURDAY...RAIN SHADOW EFFECTS WILL HINDER PRECIP CHANCES IN THE
IMPERIAL VALLEY OF SOUTHEAST CA...BUT A VERY WINDY MORNING AND
AFTERNOON IS EXPECTED.
ALTHOUGH MOST OF THE MOISTURE WILL EXIST AT OR BELOW 700 MB...
TEMPERATURES AT THESE LEVELS WILL BE VERY COLD WITH MOISTURE LOCATED
IN THE ICE XTAL/PRECIP GROWTH ZONES OF MINUS 10 DEG C AND COLDER.
COMPOUND THIS WITH 30 KNOTS 800/700 MB SOUTHWESTERLY UPSLOPE WINDS
IN SOUTHERN GILA COUNTY SATURDAY NIGHT...AND ABOUT 1 INCH OF SNOW IS
POSSIBLE AT 4500 FT...WITH 2-3 INCHES ABOVE 5000 FT. A CHANCE OF
SHOWERS IS ALSO POSSIBLE ON THE SOUTH CENTRAL AZ DESERTS INCLUDING
PHOENIX.
A FEW LINGERING SHOWERS WILL PERSIST SUNDAY MORNING BUT FOR THE MOST
PART DRIER AND COLDER AIR WILL SPREAD QUICKLY TO THE AREA. IN OTHER
WORDS CLEARING AND COLDER SUNDAY.
MONDAY AND TUESDAY...
MONDAY MORNING TEMPERATURES WILL BE COLD AGAIN...AND NEARLY SIMILAR
TO WHAT IS FORECAST TOMORROW OR FRIDAY MORNING. AGAIN...FREEZE
WARNING CRITERIA IS MARGINAL AND CERTAINLY NOTHING LIKE THE STRONG
COLD WAVES WEVE HAD IN THE RECENT PAST. OTHERWISE...MOSTLY CLEAR
SKIES ARE EXPECTED MONDAY AND TUESDAY WITH A WARMING TREND.
WEDNESDAY AND THURSDAY...
MOSTLY CLEAR WITH TEMPERATURES FINALLY APPROACHING NORMAL.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA...AND KSDL...
CLOUDINESS WILL BE CONFINED TO AREAS WELL SOUTH AND WELL EAST OF THE
PHOENIX METRO AND THAT IS WHERE SCATTERED LIGHT SHOWERS WILL BE AS
WELL...MAINLY SOUTHEAST ARIZONA. LIGHT WEST WINDS CAN BE EXPECTED
THROUGH THE DAY BECOMING LIGHT AND VARIABLE LATE TONIGHT.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA...INCLUDING KIPL AND
KBLH...
LOWER LEVEL CLOUDINESS SPILLING OVER THE COASTAL MOUNTAINS WILL
DRIFT OVER THE IMPERIAL COUNTY TODAY WITH LOCAL CIGS OF 5-7 KFT
MSL...ESPECIALLY BETWEEN 21Z-03Z. EXPECT SIGNIFICANTLY LESS
CLOUDINESS ELSEWHERE. WINDS WILL FAVOR NORTHERLY DIRECTIONS AND BE
LIGHT EXCEPT A BIT STRONGER OVER THE LOWER COLORADO RIVER VALLEY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
ANOTHER LOW PRESSURE SYSTEM WILL MOVE THROUGH THE FORECAST AREA THIS
WEEKEND. BEST CHANCE FOR PRECIPITATION WILL BE SATURDAY
NIGHT...MAINLY OVER SOUTH-CENTRAL ARIZONA. AMOUNTS WILL BE
LIGHT...LESS THAN A TENTH OF AN INCH ON THE LOWER ELEVATIONS AND UP
TO A QUARTER OF AN INCH LIQUID EQUIVALENT OVER THE HIGHER MOUNTAINS.
SNOW LEVELS WILL BE 4000-4500 FEET SATURDAY...LOWERING SEVERAL
HUNDRED FEET SATURDAY NIGHT. ACCUMULATIONS OF 2-3 INCHES ABOVE 5000
FEET ARE POSSIBLE. WINDY CONDITIONS CAN BE EXPECTED SATURDAY
AFTERNOON AND EVENING OVER SOUTHEAST CALIFORNIA...BREEZY ELSEWHERE.
CLEARING CAN BE EXPECTED SUNDAY. DRY CONDITIONS WITH NORTH AND
NORTHEAST BREEZINESS CAN BE EXPECTED MONDAY INTO
WEDNESDAY...ESPECIALLY OVER THE LOWER COLORADO RIVER VALLEY. AFTER A
COLD START MONDAY...TEMPERATURES WILL SLOWLY INCREASE.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...FREEZE WARNING IN EFFECT FOR THURSDAY NIGHT THROUGH FRIDAY
MORNING FOR AZZ021>024-026>028.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/VASQUEZ
AVIATION...AJ
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION...UPDATE
NWS PEACHTREE CITY GA
1250 PM EST THU DEC 5 2013
.UPDATE...
HAVE MADE NO CHANGES TO THE ZONES. PERIODS OF LIGHT RAIN OR DRIZZLE
WILL CONTINUE INTO THE AFTERNOON AS STRONG SOUTHERLY FLOW CONTINUES
ALOFT.
41
.UPDATE...
A QUICK UPDATE TO ACCOUNT FOR CURRENT RADAR TRENDS. FORECAST WILL
BE ISSUED SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 425 AM EST THU DEC 5 2013/
SHORT TERM /TODAY THROUGH FRIDAY/...
SHORT TERM MODELS ARE IN GOOD AGREEMENT...BUT CONTINUE TO HAVE
ISSUES WITH IMPULSES MOVING THROUGH THE UPPER LEVEL FLOW WHICH ARE
PRODUCING AREAS OF RAIN ACROSS THE FORECAST AREA. UPPER LEVEL
RIDGING BUILDS OVER FL/SE GA AS BROAD LONG WAVE TROUGH MOVES ACROSS
THE DESERT SOUTHWEST. THE SUBTLE IMPULSES MAKE IT HARD TO PINPOINT
EXACT TIMING OF RAIN TRENDS. THE RAP HAS HAD A GOOD HANDLE ON THE
AREA OF RAIN MOVING ACROSS PORTIONS OF CENTRAL GA AND LEANED HEAVILY
TOWARD RAP SOLUTION IN THE NEAR TERM. AREA OF RAIN WILL MOVE VERY
CLOSE TO ATLANTA BUT MAINLY IMPACT SOUTH AND EAST PORTIONS OF THE
METRO AREA IN THE EARLY PORTIONS OF THE MORNING RUSH HOUR...
IMPACTING AREAS NORTH OF MACON AND ATHENS THROUGH 8AM BEFORE EXITING
THE FORECAST AREA. EARLIER AREA OF RAIN ALLOWED ATMOSPHERE OVER
NORTHEAST GA TO MIX..WINDS HAVE SHIFTED OUT OF THE SOUTH AND
SOUTHWEST AND VISIBILITIES HAVE INCREASED TO 1-2 MILES. WHILE
PATCHES OF DENSE FOG WILL BE POSSIBLE TOWARD MORNING WIDESPREAD
DENSE FOG IS NOT EXPECTED AND WILL DROP THE DENSE FOG ADVISORY AT
THIS TIME BUT CONTINUE TO MONITOR THE SITUATION.
SURFACE FRONT NEAR ARKLATEX WILL SLOWLY TREK ACROSS THE GULF COAST
STATES TODAY WITH GOOD GULF MOISTURE SPREADING AHEAD OF THE FRONT
ESPECIALLY INTO WESTERN PORTIONS OF FORECAST AREA. MODELS CONTINUE
TO SHOW MUCAPE OF 400-900 NORTH OF A LINE FROM AMERICUS TO
MILLEDGEVILLE. BEST SHEAR AXIS REMAINS WEST OF FORECAST AREA...
HOWEVER ENOUGH FOR ISOLATED THUNDER ACROSS NORTH AND WEST GA
18-06Z. SEVERE IS UNLIKELY AT THIS TIME BUT LATER SHIFTS WILL
CONTINUE TO MONITOR. FRONT STALLS OR DRIFTS SLOWLY SOUTHEAST ACROSS
FORECAST AREA THROUGH FRIDAY. MODELS SHOW AN INCREASED AXIS OF
INSTABILITY ONCE AGAIN FRIDAY AFTERNOON...ENOUGH TO WARRANT ISOLATED
THUNDER ONCE AGAIN
GUIDANCE TEMPERATURES LOOK IN LINE AND HAVE TAKEN A BLEND OF MAV AND
MET...LEANING TOWARD WARMER GUIDANCE EACH DAY. OVERNIGHT LOWS
TONIGHT WILL BE CLOSE TO BREAKING SOME OF THE RECORD HIGH MINIMUM
TEMPERATURES AT THE CLIMATE STATIONS.
ATWELL
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A WET AND UNSETTLED PATTERN WILL CONTINUE UNTIL TUESDAY.
MODELS SIMILAR WITH A SLOW MOVING COLD FRONT OVER N GA FORECAST TO
MOVE TO CENTRAL GA AND S DURING THE DAY SATURDAY. HIGHEST RAIN
CHANCES ACROSS N GA FRIDAY NIGHT AND OVER THE FORECAST AREA IN
GENERAL ON SATURDAY AS A MOIST SW FLOW ALOFT MOVES OVER THE ENTIRE
AREA.
GFS/EUROPEAN SIMILAR WITH COLD AIR DAMMING SETTING UP SUNDAY NIGHT
AND CONTINUING MONDAY. RAIN AND DRIZZLE CAN BE EXPECTED FOR MUCH
OF THE AREA...WITH THE SMALLEST CHANCES OVER THE SOUTHERN PORTION
OF CENTRAL GA.
GFS/EUROPEAN SIMILAR WITH BRINGING ANOTHER COLD FRONT INTO N GA
SUNDAY NIGHT AND INTO CENTRAL GA ON MONDAY THEN EXITING THE AREA
MONDAY NIGHT. HIGHEST RAIN CHANCES WILL CONTINUE OVER N AND PORTIONS
OF CENTRAL GA UNTIL TUESDAY WHEN PRECIP CHANCES WILL END. SOME
MUCAPE ASSOCIATED WITH THE COLD FRONT AND CONDITIONS WILL NEED TO BE
MONITORED FOR THE POTENTIAL OF STRONG TO SEVERE STORMS SUNDAY NIGHT
INTO MONDAY.
LARGE VARIATIONS OF TEMPERATURES CAN BE EXPECTED FROM N TO S UNTIL
MONDAY NIGHT AND TUESDAY WHEN THE PLUNGE TO COLDER TEMPERATURES
ACROSS THE AREA OCCURS.
BDL
CLIMATE...
RECORDS FOR 12-05
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAHN 77 1977 39 1984 59 1912 20 1935
1971 1886
1905
KATL 75 1998 33 1895 60 1998 20 1899
1977
KCSG 82 1977 45 1984 63 1994 26 1960
1957
KMCN 80 1977 44 1945 64 1912 22 2000
1901
RECORDS FOR 12-06
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAHN 77 1998 37 1992 59 1912 20 1937
1962
KATL 75 2001 25 1937 57 2011 14 1937
1998
1912
KCSG 78 1951 42 1992 63 2011 24 1962
1962
KMCN 78 1924 33 1937 63 1912 20 1937
.AVIATION...
18Z UPDATE...
TAF SITES CONTINUE WITH IFR AND SOME MVFR. A SLOW IMPROVEMENT TO
MVFR EXPECTED LATE AFTERNOON...BUT CONDITIONS GOING BACK DOWN TO IFR
WITH SOME LIFR BY 06Z. PATCHES OF RAIN OR DRIZZLE THROUGH THE
EVENING AND OVERNIGHT. HAVE LEFT PREVAILING RAIN OUT OF TAFS DUE TO
DIFFICULTY IN TIMING OF INDIVIDUAL SHORT WAVES. FRONTAL BOUNDARY
SHOULD REMAIN NORTH OF THE TAF SITES THROUGH THE NIGHT. NO
CONVECTION EXPECTED. WINDS LIGHT SOUTHWEST THIS EVENING AND VARIABLE
TO LIGHT SOUTHWEST OVERNIGHT. SOUTHWEST 10 TO 15KT FRIDAY.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON ALL ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 60 76 56 / 50 50 30 50
ATLANTA 72 62 74 49 / 50 50 70 80
BLAIRSVILLE 66 60 66 46 / 60 80 90 100
CARTERSVILLE 72 63 75 45 / 50 60 90 100
COLUMBUS 76 63 79 55 / 50 40 20 60
GAINESVILLE 67 61 72 51 / 50 60 70 80
MACON 76 61 80 60 / 50 20 20 40
ROME 74 62 74 45 / 60 70 100 100
PEACHTREE CITY 72 64 77 49 / 50 40 60 80
VIDALIA 76 62 81 63 / 50 20 10 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ATWELL
LONG TERM....BDL
AVIATION...41
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
215 PM CST THU DEC 5 2013
.DISCUSSION...
345 AM CST
MAIN FORECAST FOCUS IS ON COLDER TEMPERATURES WHICH WILL AFFECT THE
MIDWEST THROUGH THE PERIOD...AND THE POTENTIAL FOR SOME LIGHT SNOW
MAINLY SOUTHEAST OF THE CWA TONIGHT AND FRIDAY...AND ACROSS MUCH OF
THE FORECAST AREA SUNDAY AND SUNDAY NIGHT. A PUSH OF EVEN COLDER
ARCTIC AIR APPEARS POSSIBLE EARLY NEXT WEEK IN THE WAKE OF THE
WEEKEND SYSTEM...LIKELY ENHANCED BY FRESH SNOW COVER.
STRONG LOW PRESSURE WAS OVER EASTERN LAKE SUPERIOR EARLY THIS
MORNING...WITH ITS TRAILING COLD FRONT WELL EAST OF THE FORECAST
AREA FROM LOWER MICHIGAN TO THE LOWER OHIO VALLEY AND ARKLATEX.
COLDER/DRIER ARCTIC AIR WAS STEADILY SPREADING INTO THE MIDWEST WITH
TEMPS IN THE TEENS/LOWER 20S AND DEW POINTS IN THE SINGLE DIGITS AND
TEENS. COLD ADVECTION WILL LIKELY OFFSET ANY DIURNAL WARMING TODAY
WITH TEMPS EXPECTED TO DIP A LITTLE MORE THIS MORNING THEN BECOME
STEADY. THOUGH APPROACHING AIR MASS IS DRIER...THERE IS CONSIDERABLE
LOW CLOUDINESS WITHIN COLD ADVECTION AND EVEN A NARROW BAND OF
FLURRIES OR LIGHT SNOW ACROSS FAR EASTERN IOWA AND NORTHWEST
ILLINOIS AT THIS HOUR. THIS APPEARS TO BE DRIVEN BY SHORT WAVE
ENERGY AND A TIGHTENING IN THE THERMAL GRADIENT AROUND NEAR 800
MB...WHICH THE RAP DEPICTS NICELY WITH AN AREA OF FRONTOGENESIS
CLOSELY TIED TO CURRENT RADAR RETURNS. THE RAP CONTINUES TO SPREAD
THIS FORCING INTO NORTH CENTRAL AND FAR NORTHERN IL EARLY THIS
MORNING BEFORE RAPIDLY WEAKENING IT PRIOR TO MIDDAY. LOW LEVEL CLOUD
COVER WILL LIKELY ERODE BY THIS AFTERNOON...THOUGH PRESENCE OF
STRONG SOUTHWESTERLY JET ALOFT AND ADDITIONAL MINOR AMPLITUDE
MID-LEVEL WAVES WILL LIKELY KEEP SOME DEGREE OF MID/HIGH CLOUDS
AROUND THROUGH THE DAY. FARTHER TO THE SOUTHEAST...SERIES OF FAST
MOVING MID-LEVEL DISTURBANCES WILL HELP TIGHTEN LOW LEVEL BAROCLINIC
ZONE ACROSS THE OHIO VALLEY...FRONT FRONTOGENETIC BANDING DEVELOPING
SNOW FROM SOUTHERN MISSOURI INTO OHIO. MODEL GUIDANCE CONTINUES TO
FOCUS AXIS OF ACCUMULATING SNOWFALL SOUTHEAST OF THE CWA LATER TODAY
INTO FRIDAY...WITH FARTHEST NORTH SOLUTIONS CLIPPING SOUTHEAST TIER
OF WFO LOT CWA COUNTIES WITH AT BEST A MINOR ACCUMULATION OF LESS
THAN A HALF INCH WITH DISTURBANCES THIS EVENING AND AGAIN FRIDAY
MIDDAY/AFTERNOON.
LITTLE CHANGE IN THINKING WITH RESPECT TO TEMPERATURES TODAY THROUGH
SATURDAY...WITH PERSISTENT INTRUSION OF ARCTIC AIR INTO FRIDAY AND
SATURDAY AS SURFACE HIGH PRESSURE EVENTUALLY BUILDS INTO THE REGION.
GUIDANCE REMAINS IN DECENT AGREEMENT WITH THE GENERAL TREND OF
20S/LOW 30S TODAY...THEN HIGHS IN THE UPPER TEENS TO LOW 20S FRI/SAT
WITH LOWS RANGING FROM THE SINGLE DIGITS NORTHWEST TO THE TEENS
SOUTHEAST.
ENERGY NOTED IN WATER VAPOR IMAGERY CURRENTLY DIGGING SOUTH INTO
BRITISH COLUMBIA IS PROGGED TO AMPLIFY OVER THE WEST COAST OVER THE
NEXT COUPLE OF DAYS...THEN MOVE EAST ACROSS THE ROCKIES AND PLAINS
SUNDAY AND ACROSS THE GREAT LAKES REGION SUNDAY NIGHT. WHILE SOME
MINOR DETAIL DIFFERENCES REMAIN IN THE LONGER RANGE MODEL
GUIDANCE...THERE IS DECENT CONSENSUS IN A BROAD SURFACE LOW
DEVELOPING ACROSS THE REGION AND LIFTING NORTHEAST ACROSS THE GREAT
LAKES SUNDAY NIGHT AND EARLY MONDAY. DRY EASTERLY FLOW IN MODIFIED
ARCTIC AIR WILL LIKELY BE A BIT SLOW TO SATURATE AS WARM/MOIST
ADVECTION DEVELOPS IN ADVANCE OF THIS SYSTEM SUNDAY...THOUGH LIGHT
SNOW IS EXPECTED TO DEVELOP FROM THE WEST/SOUTHWEST THROUGH THE
AFTERNOON. SNOW IS THEN EXPECTED SUNDAY NIGHT INTO EARLY MONDAY
MORNING...WITH CURRENT MODEL QPF SUGGESTING PERHAPS 2-3 INCHES
ACROSS ESPECIALLY THE CENTRAL AND NORTHWEST PARTS OF THE FORECAST
AREA BEFORE TAPERING TO FLURRIES MONDAY MORNING. IF THIS SNOW COVER
DOES MATERIALIZE...ANOTHER BRIEF SHOT OF ARCTIC AIR WOULD LIKELY
PRODUCE COLDER TEMPS EARLY/MID NEXT WEEK. COLDEST PERHAPS WOULD BE
TUESDAY MORNING...WHEN WEAK RIDGE AXIS WOULD SUPPORT BEST
RADIATIONAL COOLING.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* MODERATELY GUSTY WINDS TIL LATE AFTERNOON.
TRS
//DISCUSSION...UPDATED 18Z...
MVFR CEILINGS SCATTERED OUT MID MORNING. A SMALL AREA OF MVFR
CEILINGS REMAINS OVER E CENTRAL IA BUT WAS SHRINKING IN COVERAGE
AND SHOULD CONTINUE TO DO SO PER MODELS DRYING UP THIS REMAINING
POCKET OF LOWER LEVEL RH. LOCAL VFR CONDITIONS EXPECTED TO
CONTINUE THIS AFTERNOON AND THROUGH FRI WITH LOWER LEVELS
REMAINING DRY AS THE LARGE RIDGE OF HIGH PRESSURE CURVING SE FROM
WESTERN CANADA TO ACROSS THE MID MS VALLEY GRADUALLY MOVES A BIT
FURTHER E BEHIND STRONG LOW PRESSURE SLOWLY MOVING NE THEN NNE
OVER JAMES BAY AND EXTREME SOUTHERN HUDSON BAY.
TREND OF WIND SPEEDS THROUGH THE MORNING HAS BEEN TO GRADUALLY
DECREASE AND THIS IS EXPECTED TO CONTINUE THIS AFTERNOON AS THE
SURFACE PRESSURE GRADIENT OVER THE AREA SLOWLY RELAXES AS THE
EASTERN ONTARIO LOW INCHES FURTHER AWAY. DIRECTION HAS BEEN
GENERALLY W WITH SOME SUBTLE BACKING AND VEERING NOTED BETWEEN
250 AND 290 DEG. WINDS SHOULD SETTLE INTO A MORE WNW-NW DIRECTION
LATE AFTERNOON-EARLY EVENING AS THE AXIS OF THE LARGE RIDGE
GRADUALLY MOVES A BIT FURTHER EASTWARD BEHIND THE DEPARTING
ONTARIO LOW.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
*HIGH ALL ELEMENTS...WITH WIND DIRECTION +/- 20 DEG TIL LATE THIS
AFTERNOON.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT AND SATURDAY...VFR.
SUNDAY...CHANCE OF SNOW...ESPECIALLY LATE. MVFR OR LOWER POSSIBLE.
MONDAY...CHANCE OF SNOW WITH MVFR OR LOWER EARLY.
TUESDAY AND WEDNESDAY...MAINLY VFR.
LENNING
&&
.MARINE...
214 PM CST
STRONG AREA OF LOW PRESSURE JUST NORTHEAST OF LAKE
SUPERIOR...CONTINUES TO STRENGTHEN AND LIFT NORTHEAST THIS EVENING
TOWARDS JAMES BAY. A TRAILING COLD FRONT HAS PUSHED SOUTHEAST ACROSS
LAKE MICHIGAN EARLIER TODAY...WITH WINDS GENERALLY FROM THE
WEST/NORTHWEST. A TIGHT GRADIENT REMAINS ACROSS THE NORTHERN HALF OF
THE LAKE...WHERE FREQUENT GALES TO 35 KT CONTINUE. AT THIS TIME
THESE GALES ARE EXPECTED TO PERSIST THROUGH THIS EVENING...THEN AS
THE LOW PRESSURE CONTINUES TO LIFT NORTHEAST AWAY FROM THE
AREA...THE GRADIENT WILL DIMINISH WITH WINDS GALES COMING TO AN END.
FREEZING SPRAY LOOKS TO BE A DISTINCT POSSIBILITY FOR THE NORTHERN
HALF OF THE LAKE THROUGH TONIGHT.
FURTHER SOUTH THIS EVENING A CONTINUED WEST TO NORTHWEST FLOW WILL
KEEP WAVES ELEVATED ALONG THE INDIANA NEARSHORE WATERS. THIS WILL
KEEP THE SMALL CRAFT CONDITIONS GOING FOR THE INDIANA NEARSHORE THRU
FRI MORNING. WITH MUCH COLDER AIR FLOWING ACROSS THE LAKE...WHILE
THE WINDS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT CONDITIONS...IT
WILL NOT TAKE MUCH WIND TO KEEP WAVES ELEVATED. SO COULD SEE THE
NEED FOR ANOTHER EXTENSION OF THE SMALL CRAFT ADVISORY FOR INDIANA.
NORTHWEST FLOW WILL LIKELY PERSIST WITH A MUCH LIGHTER GRADIENT
THROUGH THE FIRST HALF OF THE WEEKEND...WITH HIGH PRESSURE SLIDING
OVERHEAD SUN. THEN ANOTHER SYSTEM IS FORECAST TO DEVELOP ACROSS THE
SOUTHERN PLAINS SUN...ARRIVING ACROSS THE GREAT LAKES REGION MON.
THIS SYSTEM DEEPENS QUICKLY TO 29.6 INCHES MON EVENING JUST NORTH OF
THE STRAITS OF MACKINAW. THIS WILL RESULT IN AN INCREASING GRADIENT
AND POSSIBLE GALES FOR MONDAY NIGHT THROUGH DAYBREAK TUE. THEN A
BRIEF LULL MAY OCCUR WITH A WEAK LOW PRESSURE PIVOTING EAST ACROSS
THE WESTERN GREAT LAKES TUE MORNING...THEN A TIGHT GRADIENT RETURNS
TUE NIGHT.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868 UNTIL 9 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 3 PM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 10 AM FRIDAY.
&&
$$
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
157 PM CST THU DEC 5 2013
.DISCUSSION...
345 AM CST
MAIN FORECAST FOCUS IS ON COLDER TEMPERATURES WHICH WILL AFFECT THE
MIDWEST THROUGH THE PERIOD...AND THE POTENTIAL FOR SOME LIGHT SNOW
MAINLY SOUTHEAST OF THE CWA TONIGHT AND FRIDAY...AND ACROSS MUCH OF
THE FORECAST AREA SUNDAY AND SUNDAY NIGHT. A PUSH OF EVEN COLDER
ARCTIC AIR APPEARS POSSIBLE EARLY NEXT WEEK IN THE WAKE OF THE
WEEKEND SYSTEM...LIKELY ENHANCED BY FRESH SNOW COVER.
STRONG LOW PRESSURE WAS OVER EASTERN LAKE SUPERIOR EARLY THIS
MORNING...WITH ITS TRAILING COLD FRONT WELL EAST OF THE FORECAST
AREA FROM LOWER MICHIGAN TO THE LOWER OHIO VALLEY AND ARKLATEX.
COLDER/DRIER ARCTIC AIR WAS STEADILY SPREADING INTO THE MIDWEST WITH
TEMPS IN THE TEENS/LOWER 20S AND DEW POINTS IN THE SINGLE DIGITS AND
TEENS. COLD ADVECTION WILL LIKELY OFFSET ANY DIURNAL WARMING TODAY
WITH TEMPS EXPECTED TO DIP A LITTLE MORE THIS MORNING THEN BECOME
STEADY. THOUGH APPROACHING AIR MASS IS DRIER...THERE IS CONSIDERABLE
LOW CLOUDINESS WITHIN COLD ADVECTION AND EVEN A NARROW BAND OF
FLURRIES OR LIGHT SNOW ACROSS FAR EASTERN IOWA AND NORTHWEST
ILLINOIS AT THIS HOUR. THIS APPEARS TO BE DRIVEN BY SHORT WAVE
ENERGY AND A TIGHTENING IN THE THERMAL GRADIENT AROUND NEAR 800
MB...WHICH THE RAP DEPICTS NICELY WITH AN AREA OF FRONTOGENESIS
CLOSELY TIED TO CURRENT RADAR RETURNS. THE RAP CONTINUES TO SPREAD
THIS FORCING INTO NORTH CENTRAL AND FAR NORTHERN IL EARLY THIS
MORNING BEFORE RAPIDLY WEAKENING IT PRIOR TO MIDDAY. LOW LEVEL CLOUD
COVER WILL LIKELY ERODE BY THIS AFTERNOON...THOUGH PRESENCE OF
STRONG SOUTHWESTERLY JET ALOFT AND ADDITIONAL MINOR AMPLITUDE
MID-LEVEL WAVES WILL LIKELY KEEP SOME DEGREE OF MID/HIGH CLOUDS
AROUND THROUGH THE DAY. FARTHER TO THE SOUTHEAST...SERIES OF FAST
MOVING MID-LEVEL DISTURBANCES WILL HELP TIGHTEN LOW LEVEL BAROCLINIC
ZONE ACROSS THE OHIO VALLEY...FRONT FRONTOGENETIC BANDING DEVELOPING
SNOW FROM SOUTHERN MISSOURI INTO OHIO. MODEL GUIDANCE CONTINUES TO
FOCUS AXIS OF ACCUMULATING SNOWFALL SOUTHEAST OF THE CWA LATER TODAY
INTO FRIDAY...WITH FARTHEST NORTH SOLUTIONS CLIPPING SOUTHEAST TIER
OF WFO LOT CWA COUNTIES WITH AT BEST A MINOR ACCUMULATION OF LESS
THAN A HALF INCH WITH DISTURBANCES THIS EVENING AND AGAIN FRIDAY
MIDDAY/AFTERNOON.
LITTLE CHANGE IN THINKING WITH RESPECT TO TEMPERATURES TODAY THROUGH
SATURDAY...WITH PERSISTENT INTRUSION OF ARCTIC AIR INTO FRIDAY AND
SATURDAY AS SURFACE HIGH PRESSURE EVENTUALLY BUILDS INTO THE REGION.
GUIDANCE REMAINS IN DECENT AGREEMENT WITH THE GENERAL TREND OF
20S/LOW 30S TODAY...THEN HIGHS IN THE UPPER TEENS TO LOW 20S FRI/SAT
WITH LOWS RANGING FROM THE SINGLE DIGITS NORTHWEST TO THE TEENS
SOUTHEAST.
ENERGY NOTED IN WATER VAPOR IMAGERY CURRENTLY DIGGING SOUTH INTO
BRITISH COLUMBIA IS PROGGED TO AMPLIFY OVER THE WEST COAST OVER THE
NEXT COUPLE OF DAYS...THEN MOVE EAST ACROSS THE ROCKIES AND PLAINS
SUNDAY AND ACROSS THE GREAT LAKES REGION SUNDAY NIGHT. WHILE SOME
MINOR DETAIL DIFFERENCES REMAIN IN THE LONGER RANGE MODEL
GUIDANCE...THERE IS DECENT CONSENSUS IN A BROAD SURFACE LOW
DEVELOPING ACROSS THE REGION AND LIFTING NORTHEAST ACROSS THE GREAT
LAKES SUNDAY NIGHT AND EARLY MONDAY. DRY EASTERLY FLOW IN MODIFIED
ARCTIC AIR WILL LIKELY BE A BIT SLOW TO SATURATE AS WARM/MOIST
ADVECTION DEVELOPS IN ADVANCE OF THIS SYSTEM SUNDAY...THOUGH LIGHT
SNOW IS EXPECTED TO DEVELOP FROM THE WEST/SOUTHWEST THROUGH THE
AFTERNOON. SNOW IS THEN EXPECTED SUNDAY NIGHT INTO EARLY MONDAY
MORNING...WITH CURRENT MODEL QPF SUGGESTING PERHAPS 2-3 INCHES
ACROSS ESPECIALLY THE CENTRAL AND NORTHWEST PARTS OF THE FORECAST
AREA BEFORE TAPERING TO FLURRIES MONDAY MORNING. IF THIS SNOW COVER
DOES MATERIALIZE...ANOTHER BRIEF SHOT OF ARCTIC AIR WOULD LIKELY
PRODUCE COLDER TEMPS EARLY/MID NEXT WEEK. COLDEST PERHAPS WOULD BE
TUESDAY MORNING...WHEN WEAK RIDGE AXIS WOULD SUPPORT BEST
RADIATIONAL COOLING.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* MODERATELY GUSTY WINDS TIL LATE AFTERNOON.
TRS
//DISCUSSION...UPDATED 18Z...
MVFR CEILINGS SCATTERED OUT MID MORNING. A SMALL AREA OF MVFR
CEILINGS REMAINS OVER E CENTRAL IA BUT WAS SHRINKING IN COVERAGE
AND SHOULD CONTINUE TO DO SO PER MODELS DRYING UP THIS REMAINING
POCKET OF LOWER LEVEL RH. LOCAL VFR CONDITIONS EXPECTED TO
CONTINUE THIS AFTERNOON AND THROUGH FRI WITH LOWER LEVELS
REMAINING DRY AS THE LARGE RIDGE OF HIGH PRESSURE CURVING SE FROM
WESTERN CANADA TO ACROSS THE MID MS VALLEY GRADUALLY MOVES A BIT
FURTHER E BEHIND STRONG LOW PRESSURE SLOWLY MOVING NE THEN NNE
OVER JAMES BAY AND EXTREME SOUTHERN HUDSON BAY.
TREND OF WIND SPEEDS THROUGH THE MORNING HAS BEEN TO GRADUALLY
DECREASE AND THIS IS EXPECTED TO CONTINUE THIS AFTERNOON AS THE
SURFACE PRESSURE GRADIENT OVER THE AREA SLOWLY RELAXES AS THE
EASTERN ONTARIO LOW INCHES FURTHER AWAY. DIRECTION HAS BEEN
GENERALLY W WITH SOME SUBTLE BACKING AND VEERING NOTED BETWEEN
250 AND 290 DEG. WINDS SHOULD SETTLE INTO A MORE WNW-NW DIRECTION
LATE AFTERNOON-EARLY EVENING AS THE AXIS OF THE LARGE RIDGE
GRADUALLY MOVES A BIT FURTHER EASTWARD BEHIND THE DEPARTING
ONTARIO LOW.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
*HIGH ALL ELEMENTS...WITH WIND DIRECTION +/- 20 DEG TIL LATE THIS
AFTERNOON.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT AND SATURDAY...VFR.
SUNDAY...CHANCE OF SNOW...ESPECIALLY LATE. MVFR OR LOWER POSSIBLE.
MONDAY...CHANCE OF SNOW WITH MVFR OR LOWER EARLY.
TUESDAY AND WEDNESDAY...MAINLY VFR.
LENNING
&&
.MARINE...
321 AM CST
LOW PRESSURE CROSSING LAKE SUPERIOR INTO ONTARIO THIS MORNING
DRAGGED A COLD FRONT ACROSS THE LAKE LAST EVENING. WINDS TURNED
SOUTHWEST BEHIND THE FRONT BUT ARE VEERING TO WEST THIS MORNING
AND WILL CONTINUE VEERING TO NORTHWEST TONIGHT. IN THE TIGHTER
PRESSURE GRADIENT ACROSS THE NORTHERN HALF OF THE LAKE CLOSER TO
THE LOW...GALES TO 40 KTS WITH POSSIBLY HIGHER GUSTS ARE EXPECTED
TO PERSIST INTO THIS EVENING. THE SOUTHERN HALF OF THE LAKE ALSO
WILL BE WINDY...BUT GALE FORCE GUSTS ARE EXPECTED TO BE
CONSIDERABLY LESS FREQUENT ACROSS THE SOUTH HALF. LATEST 3 AM CST
SHIP OBS IN THE FAR SOUTHERN PART OF THE LAKE HAD WIND SPEEDS
ONLY IN THE TEENS...WHILE SHIP OBS IN THE NORTHERN LAKE HAD WINDS
IN THE MID 30 KNOT RANGE.
DEBATED WHETHER TO TRIM THE END OF THE SMALL CRAFT ADVISORY FOR
THE INDIANA NEARSHORE WATERS AS THE PRESSURE GRADIENT FALLS OFF
QUICKLY THIS EVENING. DECIDED WITH SUCH COLD AIR AND A NORTHWEST
FETCH...WAVES SHOULD BE EASY TO MAINTAIN...AND GUSTS INTO THE MID
20 KNOT RANGE MAY WELL PERSIST INTO THE OVERNIGHT HOURS.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868 UNTIL 9 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 3 PM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM FRIDAY.
&&
$$
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
1154 AM CST THU DEC 5 2013
.DISCUSSION...
345 AM CST
MAIN FORECAST FOCUS IS ON COLDER TEMPERATURES WHICH WILL AFFECT THE
MIDWEST THROUGH THE PERIOD...AND THE POTENTIAL FOR SOME LIGHT SNOW
MAINLY SOUTHEAST OF THE CWA TONIGHT AND FRIDAY...AND ACROSS MUCH OF
THE FORECAST AREA SUNDAY AND SUNDAY NIGHT. A PUSH OF EVEN COLDER
ARCTIC AIR APPEARS POSSIBLE EARLY NEXT WEEK IN THE WAKE OF THE
WEEKEND SYSTEM...LIKELY ENHANCED BY FRESH SNOW COVER.
STRONG LOW PRESSURE WAS OVER EASTERN LAKE SUPERIOR EARLY THIS
MORNING...WITH ITS TRAILING COLD FRONT WELL EAST OF THE FORECAST
AREA FROM LOWER MICHIGAN TO THE LOWER OHIO VALLEY AND ARKLATEX.
COLDER/DRIER ARCTIC AIR WAS STEADILY SPREADING INTO THE MIDWEST WITH
TEMPS IN THE TEENS/LOWER 20S AND DEW POINTS IN THE SINGLE DIGITS AND
TEENS. COLD ADVECTION WILL LIKELY OFFSET ANY DIURNAL WARMING TODAY
WITH TEMPS EXPECTED TO DIP A LITTLE MORE THIS MORNING THEN BECOME
STEADY. THOUGH APPROACHING AIR MASS IS DRIER...THERE IS CONSIDERABLE
LOW CLOUDINESS WITHIN COLD ADVECTION AND EVEN A NARROW BAND OF
FLURRIES OR LIGHT SNOW ACROSS FAR EASTERN IOWA AND NORTHWEST
ILLINOIS AT THIS HOUR. THIS APPEARS TO BE DRIVEN BY SHORT WAVE
ENERGY AND A TIGHTENING IN THE THERMAL GRADIENT AROUND NEAR 800
MB...WHICH THE RAP DEPICTS NICELY WITH AN AREA OF FRONTOGENESIS
CLOSELY TIED TO CURRENT RADAR RETURNS. THE RAP CONTINUES TO SPREAD
THIS FORCING INTO NORTH CENTRAL AND FAR NORTHERN IL EARLY THIS
MORNING BEFORE RAPIDLY WEAKENING IT PRIOR TO MIDDAY. LOW LEVEL CLOUD
COVER WILL LIKELY ERODE BY THIS AFTERNOON...THOUGH PRESENCE OF
STRONG SOUTHWESTERLY JET ALOFT AND ADDITIONAL MINOR AMPLITUDE
MID-LEVEL WAVES WILL LIKELY KEEP SOME DEGREE OF MID/HIGH CLOUDS
AROUND THROUGH THE DAY. FARTHER TO THE SOUTHEAST...SERIES OF FAST
MOVING MID-LEVEL DISTURBANCES WILL HELP TIGHTEN LOW LEVEL BAROCLINIC
ZONE ACROSS THE OHIO VALLEY...FRONT FRONTOGENETIC BANDING DEVELOPING
SNOW FROM SOUTHERN MISSOURI INTO OHIO. MODEL GUIDANCE CONTINUES TO
FOCUS AXIS OF ACCUMULATING SNOWFALL SOUTHEAST OF THE CWA LATER TODAY
INTO FRIDAY...WITH FARTHEST NORTH SOLUTIONS CLIPPING SOUTHEAST TIER
OF WFO LOT CWA COUNTIES WITH AT BEST A MINOR ACCUMULATION OF LESS
THAN A HALF INCH WITH DISTURBANCES THIS EVENING AND AGAIN FRIDAY
MIDDAY/AFTERNOON.
LITTLE CHANGE IN THINKING WITH RESPECT TO TEMPERATURES TODAY THROUGH
SATURDAY...WITH PERSISTENT INTRUSION OF ARCTIC AIR INTO FRIDAY AND
SATURDAY AS SURFACE HIGH PRESSURE EVENTUALLY BUILDS INTO THE REGION.
GUIDANCE REMAINS IN DECENT AGREEMENT WITH THE GENERAL TREND OF
20S/LOW 30S TODAY...THEN HIGHS IN THE UPPER TEENS TO LOW 20S FRI/SAT
WITH LOWS RANGING FROM THE SINGLE DIGITS NORTHWEST TO THE TEENS
SOUTHEAST.
ENERGY NOTED IN WATER VAPOR IMAGERY CURRENTLY DIGGING SOUTH INTO
BRITISH COLUMBIA IS PROGGED TO AMPLIFY OVER THE WEST COAST OVER THE
NEXT COUPLE OF DAYS...THEN MOVE EAST ACROSS THE ROCKIES AND PLAINS
SUNDAY AND ACROSS THE GREAT LAKES REGION SUNDAY NIGHT. WHILE SOME
MINOR DETAIL DIFFERENCES REMAIN IN THE LONGER RANGE MODEL
GUIDANCE...THERE IS DECENT CONSENSUS IN A BROAD SURFACE LOW
DEVELOPING ACROSS THE REGION AND LIFTING NORTHEAST ACROSS THE GREAT
LAKES SUNDAY NIGHT AND EARLY MONDAY. DRY EASTERLY FLOW IN MODIFIED
ARCTIC AIR WILL LIKELY BE A BIT SLOW TO SATURATE AS WARM/MOIST
ADVECTION DEVELOPS IN ADVANCE OF THIS SYSTEM SUNDAY...THOUGH LIGHT
SNOW IS EXPECTED TO DEVELOP FROM THE WEST/SOUTHWEST THROUGH THE
AFTERNOON. SNOW IS THEN EXPECTED SUNDAY NIGHT INTO EARLY MONDAY
MORNING...WITH CURRENT MODEL QPF SUGGESTING PERHAPS 2-3 INCHES
ACROSS ESPECIALLY THE CENTRAL AND NORTHWEST PARTS OF THE FORECAST
AREA BEFORE TAPERING TO FLURRIES MONDAY MORNING. IF THIS SNOW COVER
DOES MATERIALIZE...ANOTHER BRIEF SHOT OF ARCTIC AIR WOULD LIKELY
PRODUCE COLDER TEMPS EARLY/MID NEXT WEEK. COLDEST PERHAPS WOULD BE
TUESDAY MORNING...WHEN WEAK RIDGE AXIS WOULD SUPPORT BEST
RADIATIONAL COOLING.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* MODERATELY GUSTY WINDS TIL LATE AFTERNOON.
TRS
//DISCUSSION...UPDATED 18Z...
MVFR CEILINGS SCATTERED OUT MID MORNING. A SMALL AREA OF MVFR
CEILINGS REMAINS OVER E CENTRAL IA BUT WAS SHRINKING IN COVERAGE
AND SHOULD CONTINUE TO DO SO PER MODELS DRYING UP THIS REMAINING
POCKET OF LOWER LEVEL RH. LOCAL VFR CONDITIONS EXPECTED TO
CONTINUE THIS AFTERNOON AND THROUGH FRI WITH LOWER LEVELS
REMAINING DRY AS THE LARGE RIDGE OF HIGH PRESSURE CURVING SE FROM
WESTERN CANADA TO ACROSS THE MID MS VALLEY GRADUALLY MOVES A BIT
FURTHER E BEHIND STRONG LOW PRESSURE SLOWLY MOVING NE THEN NNE
OVER JAMES BAY AND EXTREME SOUTHERN HUDSON BAY.
TREND OF WIND SPEEDS THROUGH THE MORNING HAS BEEN TO GRADUALLY
DECREASE AND THIS IS EXPECTED TO CONTINUE THIS AFTERNOON AS THE
SURFACE PRESSURE GRADIENT OVER THE AREA SLOWLY RELAXES AS THE
EASTERN ONTARIO LOW INCHES FURTHER AWAY. DIRECTION HAS BEEN
GENERALLY W WITH SOME SUBTLE BACKING AND VEERING NOTED BETWEEN
250 AND 290 DEG. WINDS SHOULD SETTLE INTO A MORE WNW-NW DIRECTION
LATE AFTERNOON-EARLY EVENING AS THE AXIS OF THE LARGE RIDGE
GRADUALLY MOVES A BIT FURTHER EASTWARD BEHIND THE DEPARTING
ONTARIO LOW.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
*HIGH ALL ELEMENTS...WITH WIND DIRECTION +/- 20 DEG TIL LATE THIS
AFTERNOON.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT AND SATURDAY...VFR.
SUNDAY...CHANCE OF SNOW...ESPECIALLY LATE. MVFR OR LOWER POSSIBLE.
MONDAY...CHANCE OF SNOW WITH MVFR OR LOWER EARLY.
TUESDAY AND WEDNESDAY...MAINLY VFR.
LENNING
&&
.MARINE...
321 AM CST
LOW PRESSURE CROSSING LAKE SUPERIOR INTO ONTARIO THIS MORNING
DRAGGED A COLD FRONT ACROSS THE LAKE LAST EVENING. WINDS TURNED
SOUTHWEST BEHIND THE FRONT BUT ARE VEERING TO WEST THIS MORNING
AND WILL CONTINUE VEERING TO NORTHWEST TONIGHT. IN THE TIGHTER
PRESSURE GRADIENT ACROSS THE NORTHERN HALF OF THE LAKE CLOSER TO
THE LOW...GALES TO 40 KTS WITH POSSIBLY HIGHER GUSTS ARE EXPECTED
TO PERSIST INTO THIS EVENING. THE SOUTHERN HALF OF THE LAKE ALSO
WILL BE WINDY...BUT GALE FORCE GUSTS ARE EXPECTED TO BE
CONSIDERABLY LESS FREQUENT ACROSS THE SOUTH HALF. LATEST 3 AM CST
SHIP OBS IN THE FAR SOUTHERN PART OF THE LAKE HAD WIND SPEEDS
ONLY IN THE TEENS...WHILE SHIP OBS IN THE NORTHERN LAKE HAD WINDS
IN THE MID 30 KNOT RANGE.
DEBATED WHETHER TO TRIM THE END OF THE SMALL CRAFT ADVISORY FOR
THE INDIANA NEARSHORE WATERS AS THE PRESSURE GRADIENT FALLS OFF
QUICKLY THIS EVENING. DECIDED WITH SUCH COLD AIR AND A NORTHWEST
FETCH...WAVES SHOULD BE EASY TO MAINTAIN...AND GUSTS INTO THE MID
20 KNOT RANGE MAY WELL PERSIST INTO THE OVERNIGHT HOURS.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868 UNTIL 9 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 3 PM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM FRIDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1013 AM CST THU DEC 5 2013
.DISCUSSION...
345 AM CST
MAIN FORECAST FOCUS IS ON COLDER TEMPERATURES WHICH WILL AFFECT THE
MIDWEST THROUGH THE PERIOD...AND THE POTENTIAL FOR SOME LIGHT SNOW
MAINLY SOUTHEAST OF THE CWA TONIGHT AND FRIDAY...AND ACROSS MUCH OF
THE FORECAST AREA SUNDAY AND SUNDAY NIGHT. A PUSH OF EVEN COLDER
ARCTIC AIR APPEARS POSSIBLE EARLY NEXT WEEK IN THE WAKE OF THE
WEEKEND SYSTEM...LIKELY ENHANCED BY FRESH SNOW COVER.
STRONG LOW PRESSURE WAS OVER EASTERN LAKE SUPERIOR EARLY THIS
MORNING...WITH ITS TRAILING COLD FRONT WELL EAST OF THE FORECAST
AREA FROM LOWER MICHIGAN TO THE LOWER OHIO VALLEY AND ARKLATEX.
COLDER/DRIER ARCTIC AIR WAS STEADILY SPREADING INTO THE MIDWEST WITH
TEMPS IN THE TEENS/LOWER 20S AND DEW POINTS IN THE SINGLE DIGITS AND
TEENS. COLD ADVECTION WILL LIKELY OFFSET ANY DIURNAL WARMING TODAY
WITH TEMPS EXPECTED TO DIP A LITTLE MORE THIS MORNING THEN BECOME
STEADY. THOUGH APPROACHING AIR MASS IS DRIER...THERE IS CONSIDERABLE
LOW CLOUDINESS WITHIN COLD ADVECTION AND EVEN A NARROW BAND OF
FLURRIES OR LIGHT SNOW ACROSS FAR EASTERN IOWA AND NORTHWEST
ILLINOIS AT THIS HOUR. THIS APPEARS TO BE DRIVEN BY SHORT WAVE
ENERGY AND A TIGHTENING IN THE THERMAL GRADIENT AROUND NEAR 800
MB...WHICH THE RAP DEPICTS NICELY WITH AN AREA OF FRONTOGENESIS
CLOSELY TIED TO CURRENT RADAR RETURNS. THE RAP CONTINUES TO SPREAD
THIS FORCING INTO NORTH CENTRAL AND FAR NORTHERN IL EARLY THIS
MORNING BEFORE RAPIDLY WEAKENING IT PRIOR TO MIDDAY. LOW LEVEL CLOUD
COVER WILL LIKELY ERODE BY THIS AFTERNOON...THOUGH PRESENCE OF
STRONG SOUTHWESTERLY JET ALOFT AND ADDITIONAL MINOR AMPLITUDE
MID-LEVEL WAVES WILL LIKELY KEEP SOME DEGREE OF MID/HIGH CLOUDS
AROUND THROUGH THE DAY. FARTHER TO THE SOUTHEAST...SERIES OF FAST
MOVING MID-LEVEL DISTURBANCES WILL HELP TIGHTEN LOW LEVEL BAROCLINIC
ZONE ACROSS THE OHIO VALLEY...FRONT FRONTOGENETIC BANDING DEVELOPING
SNOW FROM SOUTHERN MISSOURI INTO OHIO. MODEL GUIDANCE CONTINUES TO
FOCUS AXIS OF ACCUMULATING SNOWFALL SOUTHEAST OF THE CWA LATER TODAY
INTO FRIDAY...WITH FARTHEST NORTH SOLUTIONS CLIPPING SOUTHEAST TIER
OF WFO LOT CWA COUNTIES WITH AT BEST A MINOR ACCUMULATION OF LESS
THAN A HALF INCH WITH DISTURBANCES THIS EVENING AND AGAIN FRIDAY
MIDDAY/AFTERNOON.
LITTLE CHANGE IN THINKING WITH RESPECT TO TEMPERATURES TODAY THROUGH
SATURDAY...WITH PERSISTENT INTRUSION OF ARCTIC AIR INTO FRIDAY AND
SATURDAY AS SURFACE HIGH PRESSURE EVENTUALLY BUILDS INTO THE REGION.
GUIDANCE REMAINS IN DECENT AGREEMENT WITH THE GENERAL TREND OF
20S/LOW 30S TODAY...THEN HIGHS IN THE UPPER TEENS TO LOW 20S FRI/SAT
WITH LOWS RANGING FROM THE SINGLE DIGITS NORTHWEST TO THE TEENS
SOUTHEAST.
ENERGY NOTED IN WATER VAPOR IMAGERY CURRENTLY DIGGING SOUTH INTO
BRITISH COLUMBIA IS PROGGED TO AMPLIFY OVER THE WEST COAST OVER THE
NEXT COUPLE OF DAYS...THEN MOVE EAST ACROSS THE ROCKIES AND PLAINS
SUNDAY AND ACROSS THE GREAT LAKES REGION SUNDAY NIGHT. WHILE SOME
MINOR DETAIL DIFFERENCES REMAIN IN THE LONGER RANGE MODEL
GUIDANCE...THERE IS DECENT CONSENSUS IN A BROAD SURFACE LOW
DEVELOPING ACROSS THE REGION AND LIFTING NORTHEAST ACROSS THE GREAT
LAKES SUNDAY NIGHT AND EARLY MONDAY. DRY EASTERLY FLOW IN MODIFIED
ARCTIC AIR WILL LIKELY BE A BIT SLOW TO SATURATE AS WARM/MOIST
ADVECTION DEVELOPS IN ADVANCE OF THIS SYSTEM SUNDAY...THOUGH LIGHT
SNOW IS EXPECTED TO DEVELOP FROM THE WEST/SOUTHWEST THROUGH THE
AFTERNOON. SNOW IS THEN EXPECTED SUNDAY NIGHT INTO EARLY MONDAY
MORNING...WITH CURRENT MODEL QPF SUGGESTING PERHAPS 2-3 INCHES
ACROSS ESPECIALLY THE CENTRAL AND NORTHWEST PARTS OF THE FORECAST
AREA BEFORE TAPERING TO FLURRIES MONDAY MORNING. IF THIS SNOW COVER
DOES MATERIALIZE...ANOTHER BRIEF SHOT OF ARCTIC AIR WOULD LIKELY
PRODUCE COLDER TEMPS EARLY/MID NEXT WEEK. COLDEST PERHAPS WOULD BE
TUESDAY MORNING...WHEN WEAK RIDGE AXIS WOULD SUPPORT BEST
RADIATIONAL COOLING.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* GUSTY WEST WINDS SLOWLY DIMINISHING REST OF TODAY AND LOOSING
GUSTS AT SUNDOWN.
TRS
//DISCUSSION...UPDATED 16Z...
ORD AND MDW HAVE BOTH LOST THEIR MVFR CIGS IN THE PAST HOUR.
VISIBLE SATELLITE LOOP SHOWS THAT IT WILL REMAIN VFR AT ORD WHILE
MDW WILL LIKELY BE SCT V BKN TIL 17Z. STILL SOME MVFR CIGS
REMAINING OVER SE AND E CENTRAL IA...FAR NW IL AND FAR S CENTRAL
WI BUT MODELS DRY UP THIS LOW LEVEL MOISTURE BEFORE IT MUCH
FURTHER E.
GENERAL TREND IN WIND SPEEDS HAS BEEN A VERY GRADUAL DECREASE AND
EXPECT THIS TO CONTINUE THIS AFTERNOON AS THE CENTER OF LOW PRES
IN EASTERN ONTARIO CONTINUES MOVING SLOWLY NE TO JAMES BAY BY
00Z. DIRECTION GENERALLY WESTERLY WITH SOME SUBTLE BACKING AND
VEERING NOTED BETWEEN 250 AND 280 DEG. WINDS WILL VEER MORE TO
WNW-NW LATE AFTERNOON-EARLY EVENING AS THE LARGE RIDGE OF HIGH
PRES CURVING SE FROM WESTERN CANADA TO ACROSS THE MID MS VALLEY
GRADUALLY MOVES A BIT FURTHER EASTWARD BEHIND THE DEPARTING
ONTARIO LOW.
TRS
PREVIOUS... UPDATED 12Z...
DESPITE POCKETS OF VFR THE TREND THIS MORNING IS MORE LIKELY TO BE
GRADUALLY IMPROVING MVFR. SLOWED DOWN THE ARRIVAL OF HIGHER CIGS
COMPARED TO EARLIER TAFS BASED ON UPSTREAM OBS AND LATEST GUIDANCE
PRODUCTS. GUSTY WEST WINDS WILL VERY GRADUALLY VEER NORTHWESTERLY
AND BY EARLY THIS EVENING WE SHOULD LOSE THE GUSTS. ALSO INCLUDED
PERIODS OF LIGHT SNOW THIS MORNING WHICH ACTUALLY IS EXPECTED TO
BE MORE LIKE FLURRIES AND HOPEFULLY NOT ANY SORT OF PROBLEM.
LENNING
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN TIMING OF LOSS OF MVFR CEILINGS THIS
MORNING.
* HIGH CONFIDENCE IN WIND TRENDS AND OTHER ELEMENTS.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT AND SATURDAY...VFR.
SUNDAY...CHANCE OF SNOW...ESPECIALLY LATE. MVFR OR LOWER POSSIBLE.
MONDAY...CHANCE OF SNOW WITH MVFR OR LOWER EARLY.
TUESDAY AND WEDNESDAY...MAINLY VFR.
LENNING
&&
.MARINE...
321 AM CST
LOW PRESSURE CROSSING LAKE SUPERIOR INTO ONTARIO THIS MORNING
DRAGGED A COLD FRONT ACROSS THE LAKE LAST EVENING. WINDS TURNED
SOUTHWEST BEHIND THE FRONT BUT ARE VEERING TO WEST THIS MORNING
AND WILL CONTINUE VEERING TO NORTHWEST TONIGHT. IN THE TIGHTER
PRESSURE GRADIENT ACROSS THE NORTHERN HALF OF THE LAKE CLOSER TO
THE LOW...GALES TO 40 KTS WITH POSSIBLY HIGHER GUSTS ARE EXPECTED
TO PERSIST INTO THIS EVENING. THE SOUTHERN HALF OF THE LAKE ALSO
WILL BE WINDY...BUT GALE FORCE GUSTS ARE EXPECTED TO BE
CONSIDERABLY LESS FREQUENT ACROSS THE SOUTH HALF. LATEST 3 AM CST
SHIP OBS IN THE FAR SOUTHERN PART OF THE LAKE HAD WIND SPEEDS
ONLY IN THE TEENS...WHILE SHIP OBS IN THE NORTHERN LAKE HAD WINDS
IN THE MID 30 KNOT RANGE.
DEBATED WHETHER TO TRIM THE END OF THE SMALL CRAFT ADVISORY FOR
THE INDIANA NEARSHORE WATERS AS THE PRESSURE GRADIENT FALLS OFF
QUICKLY THIS EVENING. DECIDED WITH SUCH COLD AIR AND A NORTHWEST
FETCH...WAVES SHOULD BE EASY TO MAINTAIN...AND GUSTS INTO THE MID
20 KNOT RANGE MAY WELL PERSIST INTO THE OVERNIGHT HOURS.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868 UNTIL 9 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 3 PM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM FRIDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS DODGE CITY KS
219 PM CST Thu Dec 5 2013
...Updated short term discussion...
.SYNOPSIS...
ISSUED AT 1115 AM CST THU DEC 5 2013
At 12z Thursday a 1400-160kt 300mb jet extended from northeast
Colorado into the western Great Lakes. Another upper level jet was
located near the based of the 500mb trough that was positioned from
southern California into southwest Montana. A -25 to -32c 500mb
thermal trough was located near the four corners region. A surface
to 850mb ridge axis was located across from western Nebraska into
western Oklahoma and a surface cold front extended from eastern
Colorado south southeast across eastern New Mexico into west
central Texas.
&&
.SHORT TERM...(This evening through Friday)
ISSUED AT 217 PM CST THU DEC 5 2013
Upper level through that was located across southern California
and Nevada earlier today will track east and cross New Mexico by
late day. Ahead of this this upper trough some mid level moisture
will linger across western Kansas. Backing 700mb winds ahead of
this upper wave appears to enhance frontogenisis across portions
of southwest Kansas late today and early this evening which may
give rise to a period of steady light to moderate snow. Both the
NAM, GFS, and even the RAP hints at enhanced precipitation briefly
ahead of this wave along this baroclinic zone so will follow this
trend through midnight as the upper level trough moves out into
the central high plains. Given the potential for a period of
steadier snow early tonight could easily see snowfall
accumulations in the one to two inch range given the high liquid
to snow ratio. The area more favorable for this measurable
snowfall still appears to be along and south of a Ulysses to Dodge
City to Pratt line. Snow totals of around two inches still not out
of the question near the Oklahoma border so will trim several
counties out of the current winter weather advisory.
Tonight the dewpoint will be at or several degrees below zero
under mostly cloudy skies. Temperatures will be slow to fall this
evening but at this time given these expected low dewpoints, last
nights temperatures across northwest Kansas, and the low levels
cooling by a couple more degrees have decided to stay close to the
guidance for overnight lows. Given these overnight lows ranging
from around 1 degree in west central Kansas to near 10 degrees in
south central Kansas along with wind speeds of around 10 mph the
wind chills by early Friday morning are expected to fall back into
the -8 to -15 degree range. The coldest wind chills early Friday
morning will be across west central Kansas so will be issuing a
wind chill advisory for this area late tonight/early Friday.
On Friday the upper level trough will move east into the mid
Mississippi valley. Subsidence behind this disturbance may give
rise to some breaks of sun late in the day as high pressure at the
surface will continue to build into western Kansas. Despite to
break of sunshine the 900-850mb temperatures continue to support
highs only in the teens Friday afternoon.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 209 PM CST THU DEC 5 2013
Friday night:
Sfc high pressure will shift off to the east Friday night. This will
result in northeasterly winds eventually shifting southeast on the backside
of said departing high. A cold night is expected with minimums near
0F. Would not rule out a few negative values if skies clear more than
expected. Will have to watch for the potential for a wind chill advisory
during the overnight and morning hours.
Saturday and beyond:
The forecast becomes a bit more interesting during the weekend. An amplified
trof will eject from the central Rockies and out across the plains by
Sunday. This wave does have some upper level dynamics associated with
it (140-150 kt jet streak traverses across the forecast area of responsibility).
At the low levels, fairly intense warm air advection, 280-290 Kelvin
isentropic lift, and 850-600 hPa increasing frontogenesis will lead
to snow late Saturday and into Sunday. The more enhanced area of said
parameters is forecast along and north of the 850 hPa pressure perturbation
...basically the northern half of the forecast area. Models still show
low end snow advisory amounts along and north of highway 96. Even some
of the GEFS members show 2-4" of snow. There is huge bust potential
in temperatures for Sunday, should this snow/snow pack/cloud cover come
into fruition. The ECE shows a high of 8 for KDDC versus 22 from the
MEX. Will apply a slight bias towards the ECMWF solution versus the
GFS. Boise verification shows this guidance doing better than the
MEX with the current cold air mass over Kansas.
After Sunday, the forecast will remain precipitation free as isentropic
downglide and subsidence develops in the wake of the departing synoptic
trof. There is some question of when this cold air will be dislodged
and more of a low level 850 hPa downslope plume will develop. The ECMWF
indicates this possibility of seeing "warmer" temperatures (i.e. above
freezing) by mid to late next week. The deterministic runs have been
fairly consistent over the last few days.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1115 AM CST THU DEC 5 2013
An upper level disturbance will cross western Kansas late this
afternoon/early this evening. This will result in lowering
ceilings along with improving the chances for light snow at DDC
and GCK. Based on the 12z BUFR soundings the better chance for
snow at DDC and GCK will be from 21z Thursday to 03z Friday with
the ceilings lowering between 21z Thursday and 00z Friday into
MVFR category.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 5 15 0 16 / 70 0 0 30
GCK 2 15 0 13 / 50 0 0 30
EHA 2 13 1 17 / 80 0 0 30
LBL 5 15 0 15 / 80 0 0 30
HYS 4 15 0 15 / 20 0 0 40
P28 10 21 4 20 / 50 10 0 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from Midnight CST /11 PM MST/ tonight to 9
AM CST /8 AM MST/ Friday FOR KSZ043-044-061>063.
WINTER WEATHER ADVISORY until 9 PM CST this evening FOR
KSZ084>088.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Sugden
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS JACKSON KY
1116 AM EST THU DEC 5 2013
.UPDATE...
ISSUED AT 1116 AM EST THU DEC 5 2013
A WELL DEFINED AREA OF SHOWERS WITH SPORADIC ISOLATED THUNDER IS
SINKING SLOWLY SE ACROSS THE FORECAST AREA THIS MORNING. HAVE LARGELY
FOLLOWED THE SUGGESTION OF THE HRRR MODEL FOR THE PROGRESS OF THIS
DURING THE DAY. HAVE ALSO ADDED THUNDER TO TONIGHT BASED ON ELEVATED
INSTABILITY FORECAST IN THE MODELS...ESPECIALLY THE NAM. TEMPS ARE
WARMING MORE THAN WAS FORECAST AHEAD OF THE RAIN TODAY...AND HAVE
ALSO MADE ADJUSTMENTS FOR THIS.
UPDATE ISSUED AT 717 AM EST THU DEC 5 2013
THE COLD FRONT CONTINUES TO MARCH EAST...NOW ALIGNED FROM WESTERN
OHIO DOWN THROUGH WESTERN KENTUCKY. PRECIPITATION HAS BLOSSOMED ALONG
AND OUT AHEAD OF THE SURFACE BOUNDARY...WITH LOCATIONS NORTH OF THE
I-64 CORRIDOR ALREADY SEEING SOME SCATTERED TO NUMEROUS SHOWER
ACTIVITY. THERE HAVE ALSO BEEN SOME EMBEDDED THUNDERSTORMS WITHIN THE
BAND. HAVE FRESHENED UP THE POP GRIDS TO ALIGN BETTER WITH CURRENT
RADAR TRENDS. HAVE ALSO UPDATED THE HOURLY TEMPERATURES AND DEW
POINTS...AS THERE ARE STILL A FEW STRAGGLING VALLEYS...STILL
REPORTING AROUND THE 50 DEGREE MARK...THAT REFUSE TO MIX OUT.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 359 AM EST THU DEC 5 2013
VERY DYNAMIC WEATHER IS ON THE WAY AS MULTIPLE IMPACTS WILL AFFECT
THE COMMONWEALTH THROUGH THE SHORT TERM AND BEYOND.
A DEEP AREA OF SURFACE LOW PRESSURE IS CURRENTLY SITUATED ACROSS
LAKE SUPERIOR. THE ASSOCIATED COLD FRONT IS ALIGNED SOUTH ACROSS THE
OH/IN BORDER AND THEN ARCS BACK TO THE SOUTHWEST ACROSS THE OHIO
RIVER AND THEN ALONG THE MISSISSIPPI RIVER. A BAND OF CONVECTION HAS
FIRED UP ALONG THE OHIO RIVER FROM NORTH CENTRAL KENTUCKY DOWN
THROUGH WESTERN KENTUCKY IN THE PAST COUPLE OF HOURS OUT AHEAD OF THE
BOUNDARY AS IT MAKES ITS EASTWARD PUSH. MEANWHILE...EASTERN KENTUCKY
REMAINS IN THE WARM SECTOR...WITH TEMPERATURES MORE SUMMER-LIKE FOR
THE OVERNIGHT HOURS COMPARED TO NORMAL VALUES FOR EARLY DECEMBER.
THE MODELS ARE IN GOOD AGREEMENT WITH THE PROGRESSION OF THE FRONTAL
BOUNDARY THROUGH LATE THIS EVENING...CLEARING EASTERN KENTUCKY BY
DUSK AND THEN SETTLING ACROSS THE SOUTHERN APPALACHIANS WHERE IT WILL
STALL THROUGH FRIDAY BEFORE MAKING A MORE DECISIVE PUSH SOUTHEAST
INTO THE CAROLINAS BY LATE FRIDAY NIGHT.
SHOWERS WILL GRADUALLY MOVE IN FROM THE WEST THROUGH THE DAY TODAY.
POPS HAVE GENERALLY BEEN TRENDING A BIT SLOWER FOR THIS EVENT...SO
WILL ONLY CARRY ISOLATED TO SCATTERED POPS IN THE EAST THROUGH THE
MORNING...UNTIL THE FRONT DRAWS CLOSER. THERE WILL BE SOME
INSTABILITY AVAILABLE TODAY AND GIVEN THAT THERE HAS ALREADY BEEN AT
LEAST SOME IN CLOUD LIGHTNING ACTIVITY OUT WEST ALREADY...WILL
INCLUDE SOME SLIGHT CHANCES FOR THUNDER. GIVEN THE STRONGER WIND
PROFILE IN THE LOW LEVELS...IT IS NOT TOTALLY OUT OF THE QUESTION
THAT SOME GUSTY WINDS IN THE 30 TO 40 MILE PER HOUR RANGE COULD MIX
DOWN.
HIGHS TODAY WILL LIKELY BE ESTABLISHED IN THE EARLY PART OF THE DAY
ACROSS THE NORTHWEST PORTION OF THE AREA...BEFORE THE COLD FRONT
COMES THROUGH AND BRINGS MUCH COOLER AIR BEHIND IT. EXPECT STEADY
RAINS TO PICK UP TONIGHT...POSSIBLY FALLING HEAVY AT TIMES...AS WAVES
OF LOW PRESSURE RIDE UP ALONG THE SURFACE BOUNDARY.
ON FRIDAY...BOTH THE NAM AND GFS ARE INDICATING THE OVERALL BEST LIFT
TO PASS THROUGH FRIDAY AFTERNOON AS SOME 850-700 MB FRONTOGENETIC
FORCING RAMPS UP ACROSS THE AREA AS A BETTER EMBEDDED SHORT WAVE
PASSES BY OVERHEAD. THIS WILL BRING ANOTHER THREAT OF THUNDER
POTENTIALLY AND WILL MAINTAIN SLIGHT CHANCES THERE. THE BEST 12 HOUR
QPF WILL ALSO LIKELY OCCUR ON FRIDAY...WITH 1 TO 1.5 INCHES
POSSIBLE...SO ISOLATED FLOODING OF LOW LYING AREAS AND SIGNIFICANT
RISES ON RIVERS STILL LOOKS ON TARGET. TOTAL RAINFALL FOR THIS BATCH
OF RAINFALL REMAINS IN THE 2 TO 3 INCH RANGE...WITH A BIT OF A
LIGHTER TREND OVERALL IN THE PAST COUPLE OF DAYS.
FINALLY...AS DEEPER MOISTURE BEGINS TO PULL AWAY LATE FRIDAY
AFTERNOON INTO FRIDAY EVENING...ENOUGH COLDER AIR WILL GRADUALLY
UNDERCUT THE WARM NOSE ALOFT AND ALLOW FOR A SNOW...SLEET...AND
PERHAPS FREEZING RAIN/ DRIZZLE THREAT. IMPACTS FROM THIS LOOK TO BE
ADVISORY CRITERIA AT WORST AS THE GROUND WILL BE VERY WARM AND DEEPER
MOISTURE CUTS OFF QUICKLY. THERE WILL LIKELY BE A SHARP CUTOFF WHERE
THE WINTRY MIX FALLS AND CREATES SOME TEMPORARY SLICK
CONDITIONS...MOST LIKELY NORTHWEST OF A LINE FROM SANDY HOOK TO
STANTON. ANOTHER POTENTIAL ISSUE WILL BE SOME REFREEZING THAT TAKES
PLACE OVERNIGHT FRIDAY NIGHT AS ARCTIC AIR INVADES FROM THE
NORTHWEST. OVERNIGHT LOWS WILL RANGE FROM THE LOW TO MID 20S
NORTHWEST...TO AROUND 30 IN THE SOUTHEAST.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 452 AM EST THU DEC 5 2013
VERY COMPLICATED WEATHER PATTERN THROUGH THE FIRST SEVERAL DAYS OF
THE EXTENDED FORECAST. FAIRLY GOOD AGREEMENT EXISTED BETWEEN THE GFS
AND ECMWF MODELS FOR THIS TIME FRAME...BELIEVE IT OR NOT. THE
OVERALL WEATHER PATTERN TO START THE EXTENDED IS PROGGED TO FEATURE
COLD AND MOIST NORTH TO NORTHWEST FLOW BEHIND A DEPARTING FRONTAL
BOUNDARY. BASED ON THE LATEST FORECAST SOUNDINGS AND TIME HEIGHT
CROSS SECTIONS...THERE WILL EXIST THE POSSIBILITY OF FREEZING
DRIZZLE THROUGH LATE SATURDAY MORNING. THIS PRECIPITATION WILL TAPER
OFF QUICKLY TO DRIZZLE BY EARLY AFTERNOON...WITH THE REST OF THE
AFTERNOON AND EARLY EVENING FREE OF PRECIPITATION. THIS WILL CHANGE
QUICKLY...HOWEVER...AS ANOTHER STORM SYSTEM MOVES IN FROM THE SOUTH.
THIS SECOND WEATHER SYSTEM IS FORECAST TO MATERIALIZE OVER THE
WESTERN GULF OF MEXICO SATURDAY AND SATURDAY NIGHT. AN AREA OF LOW
PRESSURE IS EXPECTED TO FORM OVER SOUTHERN TEXAS...ALONG THE WESTERN
OF EDGE OF THE PREVIOUSLY STALLED FRONTAL BOUNDARY. ONCE THIS AREA
OF LOW PRESSURE BECOMES BETTER DEFINED SATURDAY NIGHT...IT WILL GET
CAUGHT UP IN THE SOUTHERN BRANCH OF THE JET STREAM...AND CARRIED
NORTHEASTWARD ACROSS THE TENNESSEE AND OHIO VALLEY REGIONS. WITH
COLD AIR ALREADY IN PLACE AT THE SURFACE...A WINTRY MIX OF
PRECIPITATION WILL QUICKLY FORM NORTH OF THE APPROACHING LOW LATE
SATURDAY NIGHT THROUGH THE MORNING IN ON SUNDAY. THE PRECIPITATION
WILL LIKELY BEGIN AS ALL SNOW FOR A BRIEF PERIOD...BEFORE
TRANSITIONING TO A MIX OF FREEZING RAIN...SLEET...AND SNOW AS MOIST
AIR OVERRUNS THE COLD SURFACE AIR MASS. SOME LIGHT ICE ACCUMULATIONS
WILL BE POSSIBLE EARLY IN THE DAY...BUT WARMING TEMPERATURES AND
RAIN SHOULD MELT MOST OR ALL OF THIS OF LATER IN THE DAY. THE
SURFACE TEMPERATURES WILL GRADUALLY WARM UP DURING THE DAY ON
SUNDAY...WITH PRECIPITATION GRADUALLY CHANGING BACK OVER TO RAIN FROM
SOUTH TO NORTH BY SUNDAY AFTERNOON.
TEMPERATURES SHOULD REMAIN WARM ENOUGH FOR PRECIPITATION TO REMAIN
IN LIQUID FORM SUNDAY NIGHT AND MONDAY. ANOTHER SHOT OF COLD AIR IS
THEN EXPECTED TO FILTER SOUTH MONDAY AND TUESDAY...AS WINDS SHIFT TO
THE WEST AND NORTHWEST BEHIND THE DEPARTING WEATHER SYSTEM. SOME
LIGHT SNOW ACCUMULATIONS WILL BE POSSIBLE AS THIS SYSTEM MOVES OFF
TO THE NORTHEAST. WITH SIGNIFICANT DIFFERENCES BETWEEN THE LATEST
MEXMOS AND ECEMOS NUMBERS...DECIDED TO GO WITH A BLEND BETWEEN THE
TWO FOR FORECAST HIGHS AND LOWS ACROSS THE BOARD. PRECIPITATION
COULD BECOME MODERATE AT TIMES SATURDAY NIGHT AND SUNDAY...AS AMPLE
GULF MOISTURE WILL BE FEEDING INTO THE AREA FROM THE SOUTH.
A LARGE AREA OF HIGH PRESSURE WILL THEN SETTLE OVER THE REGION FROM
TUESDAY ONWARD...BRINGING VERY COLD TEMPERATURES TO THE AREA FOR
SEVERAL DAYS. HIGHS TUESDAY ONWARD WILL BE HARD PRESSED TO REACH THE
UPPER 30S FOR MOST LOCATIONS...WITH OVERNIGHT LOWS DROPPING INTO THE
TEENS AND LOWER 20S TUESDAY NIGHT AND WEDNESDAY NIGHT. HIGHS OVER
THE WEEKEND WILL TOP OUT MOSTLY IN THE 30S ON SATURDAY...AND IN THE
40S FOR ALL BUT THE NORTHWESTERN COUNTIES OF THE FORECAST
AREA...WHERE HIGHS WILL ONLY MAKE IT TO THE MID 30S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 717 AM EST THU DEC 5 2013
CONDITIONS WILL GRADUALLY DETERIORATE THROUGH THE PERIOD AS A COLD
FRONT MOVES SOUTHEAST ACROSS THE COMMONWEALTH AND THEN STALLS JUST
SOUTHEAST OF THE AREA. THIS WILL BRING A PROLONGED PERIOD OF RAIN
WITH IFR CEILINGS/VISIBILITIES AT TIMES. AN AMPLE LOW LEVEL JET
WILL PROVIDE THE THREAT OF LOW LEVEL WIND SHEAR EAST OF I-75 THROUGH
15Z. SOUTH WINDS AT AROUND 10 KTS WILL GRADUALLY VEER TO THE SOUTHWEST
DURING THE DAY...AND THEN SHIFT TO THE NORTHWEST BEHIND THE COLD
FRONT LATER THIS AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH SATURDAY MORNING
FOR KYZ044-050>052-058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...HAL
SHORT TERM...GEOGERIAN
LONG TERM...AR
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS GRAY ME
1204 PM EST THU DEC 5 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL MOVE INTO NEW ENGLAND ON TODAY...
SPREADING SOME LIGHT PRECIPITATION INTO THE REGION. THE FRONT WILL
PUSH OFFSHORE TONIGHT. A WAVE OF LOW PRESSURE WILL TRACK
NORTHEAST ALONG THE FRONT ON FRIDAY AND MAY SPREAD RAIN OR SNOW
INTO SOUTHERN AREAS. HIGH PRESSURE PUSHES THE FRONT FURTHER SOUTH
ON SATURDAY WITH COLDER AIR MOVING IN. HIGH PRESSURE SHIFTS EAST
ON SUNDAY WITH LOW PRESSURE TRACKING UP THE EAST COAST ON MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NOON...SOME SHELTERED AREAS IN INTERIOR ME STILL BELOW FREEZING
WITH SOME -SHRA MOVING THRU. AS WITH PLACES WHERE SHRA MOVES THRU
EARLIER...THESE SHOULD BUT UP A FEW DEGREES AS THE RAIN MIXES SOME
WARMER AIR DOWN...SO FZRA LOOKS TO BE BE ISOLATED AND BRIEF. BACK
OFF POPS TO REFLECT MORE SCT PRECIP THIS AFTERNOON...AS STEADIER
RAIN LOOKS TO BE MORE LKLY TONIGHT.
855 AM...SFC WARM FRONT IS PROGRESSING NWD WITH LITTLE IN THE WAY
OF ANY PRECIP ATTM. ONLY PRECIP NEARBY IS LIGHT RA IN CENTRAL
MA/CT. PREV TREND IS FOR ANY RAIN TO MIX DOWN WARMER /ABV FRZING/
TEMPS AND WEAKEN INVERSION...THEREFORE THREAT OF ANY PATCHY FZRA
IS EXTREMELY S OF THE MTNS. CANNOT RULE OUT A FEW POCKETS OF FZRA
IN THE COLDER SPOTS OF THE MTNS THIS AFTERNOON...BUT THESE WOULD
BE SHORT-LIVED AND ISOLATED. OTHERWISE...LOOK FOR TEMPS TO SLOWLY
THROUGH THE DAY AND INTO THE EVENING.
UPDATE...
SOUTHERN AREAS CONTINUE TO SLOWLY WARM AS WARM AIR ADVECTION
REMAINS IN FULL SWING THIS MORNING. SOME VERY LIGHT ECHOES PER
LATEST 88D IMAGERY EXISTS OVER SOUTHERN NEW HAMPSHIRE EARLY THIS
MORNING. MUCH OF THIS PRECIPITATION IS NOT MAKING IT TO THE GROUND
DUE TO A DRY COLUMN IN PLACE OVER NORTHERN NEW ENGLAND.
WILL CONTINUE TO MONITOR FOR PATCHY FREEZING DRIZZLE. HOWEVER...NO
REPORTS AS OF 12Z. USED THE BTV TOP/DOWN WEATHER TOOL. WILL NOT BE
ISSUING AN ADVISORY WITH SUCH LOW CHANCE POPS FOR ICE THIS MORNING.
TIDES WILL NEED TO BE MONITORED ONCE AGAIN TODAY. SHOULD COME UP
CLOSE TO THE 12 FOOT FLOOD STAGE IN PORTLAND. HOWEVER...WITHOUT
MUCH WIND OR WAVE ACTION...PROBLEMS ARE NOT EXPECTED. HOWEVER...WATER LEVELS
IN HAMPTON WILL BE RUNNING HIGH TODAY.
PREV DISC...
MODELS HAVE BACKED OFF ON THE TIMING OF ANY PRECIPITATION IN
ASSOCIATION WITH THE APPROACHING FRONT EARLY THIS MORNING WITH
EACH CONSECUTIVE RUN. HOWEVER...A WEAK AREA OF LOW PRESSURE OFF
THE NEW JERSEY COASTLINE IS BEGINNING TO GENERATE SOME LOW LEVEL
PRECIPITATION IN THE FORM OF LIGHT DRIZZLE AND LIGHT RAIN. WITH
TEMPERATURES IN THE LOWER TO MIDDLE 20S ACROSS THE REGION...EXPECT
SOME OF THIS MAY FREEZE ON CONTACT IF IT ARRIVES EARLY ENOUGH
PRIOR TO OUR EXPECTED DAYTIME WARM UP TODAY. WILL CONTINUE TO
MONITOR THIS VERY CLOSELY AS LATEST HRRR RUN BRINGS LIGHT MIXED
PRECIPITATION INTO FAR SOUTHERN AREAS SHORTLY AFTER 12Z.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
FROPA FINALLY OCCURS TONIGHT...CHANGING THE PRECIPITATION FROM A
STRATIFORM TO A SHOWERY TYPE OF WEATHER. TEMPERATURES IN THE
MOUNTAINS WILL BE COOLING OFF...SO THERE MAY BE SOME LIGHT
ACCUMULATIONS IN ANY PERSISTENT SNOW SHOWERS OVER THE HIGH
TERRAIN. USED A BLEND OF MAV/MET MOS WHICH BRINGS TEMPERATURES IN
THE MOUNTAINS TO BELOW FREEZING BY FRIDAY MORNING.
MODELS ARE IN DISAGREEMENT BY LATE IN THE DAY ON FRIDAY AS TO
WHETHER A WAVE OF LOW PRESSURE WILL RIDE UP THE FRONT AND SOUTH OF
NEW ENGLAND OR NOT. CURRENTLY...THE NAM IS MOST AGGRESSIVE WITH THE
NORTHERN PROXIMITY OF PRECIPITATION...WHICH LEADS US TO THE LONG
RANGE PORTION OF THE FORECAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
FRI NIGHT A WEAK WAVE OF LOW PRES WILL MOVE E ALONG A STALLED
FRONT LOCATED S OF NEW ENGL. SRN AREAS OF ME/NH WILL BE ON THE NRN
FRINGE OF THE PCPN SHIELD SO SOME LGT PCPN IS EXPECTED. THE PCPN
SHOULD PRODUCE PSBLY A FEW INCHES OF SNOW OVER SRN AREAS AS ANY
MIXED PCPN GRDLY CHANGES TO SNOW AS CAA OCCURS FRI NIGHT. BY SAT
MRNG SKIES CLEAR AS HIGH PRES BUILDS ACROSS THE REGION. HIGH PRES
BECOMES CENTERED OVER THE REGION SUN ALLOWING ANOTHER NICE DAY.
SUN NIGHT THE SFC/UPR RDG AXIS OVR NEW ENGL MOVES EWD ALLOWING A
MOIST SWLY FLOW TO DEVELOP AS A BROAD WAA PATTERN DEVELOPS AND
MOVES EWD INTO THE REGION BY MON MORNING. MODELS IN GENERAL
AGREEMENT THAT CONDS WILL BE COLD ENOUGH FOR SNOW AND SOME ACCUMS
EXPECTED AT THE ONSET MON MRNG BEFORE CHANGING OVER TO A MIX AND
THEN RAIN FROM S-N DURING THE DAY. BY MON NIGHT SYSTEM RAPIDLY
EXITS AND CLEARING EXPECTED AS A STRONG COLD FRONT MOVES THROUGH
THE REGION LATE IN THE SYSTEMS WAKE. TUES AND WED MUCH COLDER
TEMPS EXPECTED WITH BELOW NORMAL TEMPS EXPECTED.
ACCEPTED TIMING AND POPS OF SUPERBLEND GUID FOR DAYS 4-7.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
SHORT TERM...CONDITIONS GRADUALLY DETERIORATE THIS MORNING WITH LOW
CLOUDS AND POSSIBLY FOG/DRIZZLE MOVE IN. THIS COULD LEAD TO AN
EXTENDED PERIOD OF IFR OR LIFR CONDITIONS THROUGH TONIGHT...BEFORE
SLOWLY IMPROVING TO MVFR CONDITIONS ON FRIDAY.
LONG TERM...
FRI NIGHT IFR CONDS IN SNW OR MIXED PCPN OVER SRN AREAS WHILE NRN
AND CNTRL AREAS MAILY VFR. ON SAT CONDS BECOME VFR ACROSS ALL
AREAS AND CONTINUE THRU SUNDAY. THE NEXT SYSTEM APPROACHES SUN
NIGHT AND MON LOWERING CONDS TO IFR/LIFR ACROSS ALL AREAS.
&&
.MARINE...
SHORT TERM...SOUTHERLY FLOW TODAY WILL GRADUALLY BUILD 3 TO 5 FOOT
WAVES WITH TIME. WILL ISSUES SCA FOR SEAS...WHICH WILL CARRY ON
INTO FRIDAY. THIS IS FOR THE OUTER WATERS ONLY.
LONG TERM...
NO FLAGS FRI NIGHT AND SAT. NW WINDS MAY APPROACH SCA CONDS SUN.
ON MON AN INCRG E FLOW WILL PRODUCE SCA CONDS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 PM THIS
AFTERNOON TO 4 PM EST FRIDAY FOR ANZ150-152-154.
&&
$$
SYNOPSIS...
NEAR TERM...CEMPA
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
424 PM EST THU DEC 5 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS OFF THE COAST THROUGH TONIGHT. A SLOW
MOVING COLD FRONT IS EXPECTED TO MOVE INTO THE AREA BY MID DAY
FRIDAY...FOLLOWED BY A PERIOD OF UNSETTLED WEATHER THROUGH EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
MILD S-SW FLOW CONTINUES ACROSS THE REGION INTO TONIGHT...WITH SFC
HIGH PRESSURE SITUATED OFF THE COAST. ABUNDANT LOW-LEVEL MOISTURE
IN PLACE TONIGHT (DEW PTS IN THE 50S TO AROUND 60) WILL ALLOW
CLOUDS TO REMAIN PLENTIFUL...WITH PATCHY DENSE FOG POSSIBLE AGAIN
ESPECIALLY ALONG THE COAST AND OVER THE WATERS. LATEST RADAR
COMPOSITE SHOWS A BATCH OF SHOWERS MOVING EAST AND OFF THE LOWER
MD EASTERN SHORE. MEANWHILE...ANOTHER BATCH OF SHOWERS IS PUSHING
EAST ACROSS SOUTHERN VA AND NE NC. THESE SHOWERS WILL CONTINUE TO
MOVE EAST THROUGH THE EVENING HOURS AND WILL CARRY CHC POPS
(30-40%) DURING THIS TIME. A COLD FRONT WILL CONTINUE TO MOVE
EASTWARD FROM THE OHIO VALLEY AND GETS HUNG UP ALONG THE SPINE OF
THE APPALACHIANS LATE TONIGHT INTO FRI MORNING. THIS IS DUE TO A
BLOCKING PATTERN DEVELOPING...WHERE A STRONG ARCTIC HIGH IS
DIGGING INTO THE NCTRL U.S. AND ANOTHER HIGH IN THE WRN ATLANTIC
IS PREVENTING THE COLD FRONT FROM PROGRESSING EWD. ONCE ANY LIGHT
SHOWERS END THIS EVENING...A DRY PERIOD IS ANTICIPATED OVERNIGHT.
MOISTURE AND WEAK SHORTWAVE ENERGY THEN RIDES ALONG THE FRONT FROM
SW TO NE AND MAY BRING PCPN BACK INTO FAR NW PORTIONS OF THE FA
TOWARD DAYBREAK. MILD TONIGHT WITH LOWS IN THE UPR 50S TO LOW 60S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
THE COLD FRONT TO THE NORTHWEST WILL EVENTUALLY START TO SAG
SOUTHWARD BY FRIDAY AFTERNOON. AHEAD OF THE BOUNDARY...SW FLOW
WILL ALLOW MILD AND DRY CONDITIONS TO CONTINUE. ALONG AND NORTH
OF THE BOUNDARY...AM EXPECTING STEADIER PCPN TO ARRIVE ACROSS
NORTHERN AREAS...ESPECIALLY IN THE AFTERNOON. AS FAR AS POPS
GO...HAVE LIKELY POPS (60%) SPREADING SOUTHWARD TO ALONG A
FLUVANNA TO HANOVER TO DORCHESTER MD LINE BY LATE FRIDAY
AFTERNOON. FARTHER SOUTH...WILL KEEP THE FORECAST DRY MAINLY ALONG
AND SOUTH OF VA HWY 58. CONTINUED WAA ADVECTION SOUTH OF THE FRONT
AND FAVORABLE MIXING WILL HELP BOOST HIGH TEMPS WELL ABOVE NORMAL
ON FRI...ESPECIALLY OVER SRN AREAS WHERE TEMPS SHOULD REACH THE
MID-UPPER 70S. RECORDS ARE NOT EXPECTED TO BE BROKEN (SEE CLIMATE
SECTION BELOW). FOR NW AREAS...TEMPS MAY ONLY BE IN THE LOW-MID
60S DEPENDING ON WHERE LOW CLOUDS AND PRECIP OCCUR. THE COLD FRONT
SWEEPS THROUGH THE REST OF THE FA FRI NIGHT AND MOVES SOUTH OF THE
AREA SAT MORNING. PRECIPITATION IS EXPECTED TO BECOME MORE
WIDESPREAD AND STEADY OVERNIGHT FRI. LOW TEMPS WILL BE TRICKY
DEPENDING ON HOW FAST THE POST-FRONTAL ARCTIC AIR CAN MOVE INTO
THE REGION AND WHEN WINDS TURN TO THE NORTHWEST/NORTH. AM
CURRENTLY ANTICIPATING A CONTRAST WITH LOWS IN THE UPPER 30S/LOWER
40S NW TO LOW/MID 50S FAR SE.
SATURDAY...
THE AFOREMENTIONED COLD FRONT STALLS OUT ACROSS THE SERN U.S. AS
ARCTIC HIGH PRESSURE EXPANDS EWD FROM THE OHIO VALLEY AND INTO THE
NORTHEAST. N-NE SFC WINDS WILL CONTINUE TO FUNNEL COLDER AIR INTO
THE MID ATLANTIC REGION THROUGH SAT WITH HIGHS EITHER HOLDING
STEADY OR ONLY RISING A COUPLE OF DEGREES FROM THEIR MORNING LOWS.
HIGHS AROUND 40 NW TO THE LOW/MID 50S FAR SE. THE QUESTION THAT
STILL REMAINS IS JUST HOW MUCH PRECIP LINGERS ACROSS THE LOCAL
AREA ON SATURDAY. ATTM...THE ECMWF AND GFS MODELS STILL FAVOR
LIGHT RAIN LINGERING ALONG AND SOUTH OF A FARMVILLE-RICHMOND-
SALISBURY LINE IN THE MORNING...THEN SHIFTING INTO JUST FAR
SOUTHERN VA AND NE NC IN THE AFTERNOON. THE NAM/SREF SOLUTIONS NOT
ONLY DRIVE THE SFC COLD FRONT A LITTLE FARTHER SOUTH BUT THEY
FLATTEN THE FRONT INTO A MORE WEST TO EAST ORIENTATION...WHICH
SUPPORTS LESS PRECIPITATION SAT AFTN. CONTINUE TO FAVOR THE PRECIP
GETTING HUNG UP NEAR SE COASTAL AREAS AND BEING SLOWER TO EXIT THE
REGION CONSIDERING THE GIVEN POSITION/STRENGTH OF THE WRN ATLANTIC
RIDGE. WILL KEEP BEST PRECIP CHANCES ACROSS THE SERN HALF OF THE
FA THROUGHOUT THE DAY.
SATURDAY NIGHT...
MODELS ARE IN GENERAL AGREEMENT WITH LAYING THE FRONTAL BOUNDARY
INTO A MORE FLAT W-E ORIENTATION SAT NIGHT...THEN PULLING IT BACK
UP THE APPALACHIANS ALMOST LIKE A RETROGRADING LEE TROUGH.
SHORTWAVE ENERGY MOVING UP THIS BOUNDARY FROM THE TN VALLEY IS
EXPECTED TO ENHANCE AND SPREAD PRECIPITATION BACK INTO THE REGION
FROM THE SOUTH/SOUTHWEST OVERNIGHT. MEANWHILE...A COLD AIR WEDGE IS
BEGINNING TO TAKE FORM AS COLD ARCTIC AIR FILTERS INTO THE REGION
FROM THE N/NE. THE COMBINATION OF WARMER AIR IN THE SOUTHEAST
VERSUS THE COLDER AIR TO THE NORTH WILL MAKE FOR A TRICKY
PRECIP-TYPE FORECAST. MODEL DISCREPANCIES REGARDING PRECIP
PLACEMENT AND TIMING ARE DIFFERENT ENOUGH TO MAKE IT DIFFICULT TO
DETERMINE WHERE RAINFALL WILL TRANSITION TO SLEET AND/OR FREEZING
RAIN. AT THIS TIME...THE GFS/ECMWF ARE THE MOST PROGRESSIVE IN
PUSHING THE PRECIP NWD OVERNIGHT. THE NAM HAS MORE OF A DRY LOOK
TO IT...NOT BRINGING PRECIP BACK INTO SW PORTIONS OF THE FA UNTIL
AROUND 12Z SUN. THIS DELAY IS ALSO RESULTING IN A COLDER
TEMPERATURE BIAS OVER NWRN AREAS. THE SREF SPLITS THE DIFFERENCE
BTWN THE FAST GFS/ECMWF AND THE SLOWER/COLDER NAM. USING THICKNESS
HEIGHTS AND WET BULB ZERO TEMPS TO DETERMINE A GENERAL P-TYPE...
HAVE INTRODUCED SOME FREEZING RAIN AND SLEET INTO NW PORTIONS OF
THE FA EARLY SUNDAY MORNING. A MIX OF RAIN AND FREEZING RAIN WILL
BE POSSIBLE EAST OF I-95 FROM EMPORIA TO NEW KENT COUNTY INTO THE
NORTHERN NECK DURING THIS TIME. FARTHER EAST...ALL RAIN IS
EXPECTED SATURDAY NIGHT...WITH THE LOWER MD EASTERN SHORE PROBABLY
REAMINING FREE OF PRECIP UNTIL AFTER 12Z SAT. LOW TEMPS ARE
EXPECTED TO BE BELOW FREEZING WEST OF A LINE FROM EMPORIA TO NEW
KENT TO THE INTERIOR LOWER MD EASTER SHORE...AND IN THE MID 30S TO
NEAR 40 SOUTH AND EAST AND SE OF THIS LINE.
SUNDAY...
THE CHALLENGING FORECAST CONTINUES INTO SUNDAY WHEN OVERRUNNING
PRECIP CONTINUES TO OVERSPREAD THE COLD NEAR-SURFACE AIR. MODEL
CONSENSUS FOR SUNDAY SHOWS A LITTLE BIT COLDER TEMPS THAN WHAT HAS
BEEN PREVIOUSLY EXPECTED WITHIN THE CAD SETUP...ESPECIALLY THE NAM
AND GFS. THE COLDER TREND MEANS THERE IS A POSSIBILITY FOR FROZEN
PRECIP TO HOLD ON LONGER ALONG/WEST OF THE I-95 CORRIDOR...AND
THEREFORE SUGGESTING A HIGHER POSSIBILITY OF WINTER WX HEADLINES
BEING NECESSARY ACROSS THE AREA. IF THE ATMOSPHERE DOES IN FACT
START OUT COLDER...THEN THERE COULD BE MORE SNOW/SLEET THAN FIRST
THOUGHT ACROSS THE NW AS WELL BEFORE A CHANGEOVER TO FREEZING
RAIN. BECAUSE OF THE UNCERTAINTIES WITH P-TYPES AND DURATION OF
FROZEN PRECIP...WILL NOT GET TOO SPECIFIC WITH THE FORECAST JUST
YET. HAVE CONTINUED THE TREND OF SHOWING THE POSSIBILITY OF FROZEN
PRECIP ON SUNDAY...ESPECIALLY THROUGH EARLY AFTERNOON...ALONG AND
NORTH OF A LUNENBURG TO TRI-CITIES TO NORTHERN NECK TO SALISBURY
LINE. HIGHS SUNDAY WILL RANGE FROM THE LOW/MID 30S WEST TO THE LOW
50S ALONG THE SE COAST.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
DUE TO THE 12Z MODELS COLDER AND SLOWER WITH ONSET OF THE EVENT
SUNDAY...BUFKIT DATA NOW SUPPORTS A CONTINUATION OF P-TYPE ISSUES
ACROSS NWRN MOST COUNTYS THROUGH SUNDAY EVENING AS THE WEDGE WILL
BE LOCKED IN PLACE. SO WILL CONTINUE THE FZ RAIN FOR LOUISA/
FLUVANNA/WESTERN GOOCHLAND AND WESTERN CAROLINA COUNTY THROUGH
MIDNIGHT. OTW...RAIN CONTINUES ACROSS THE FA WITH STEADY TEMPS
MOST OF THE NIGHT...SLOWLY RISING AFTER 08Z AS A WEAK WAVE OF LOW
PRESSURE PULLS SOME OCEANIC AIR INLAND.
FIRST WAVE OF LOW PRESSURE MOVES NE OF FA MON MORNING WITH MODELS
INDICATING A SERIES OF WEAK WAVES MOVING NE AHEAD OF THE NEXT COLD
FRONT THAT WILL CROSS THE REGION LATE MONDAY AFTERNOON AND NIGHT.
ENOUGH MOISTURE PROGGED TO CONTINUE THE RAIN CHCS ACROSS THE AREA
MON. MUCH MILDER AS THE FLOW BECOMES SW BUT THE COLD FRONTAL PASSAGE
RESULTS IN ANOTHER TRICKY TEMP FORECAST. EXPECT A WIDE RANGE IN
TEMPS AS RESIDUAL WEDGING LEADS TO TEMPS HOLDING AROUND 50 NORTHERN
MOST COUNTYS...WITH MUCH MILDER AIR (AND MAYBE SOME PARTIAL SUN)
RESULTING IN TEMPS WARMING INTO THE 60S AND POSSIBLY NEAR 70 IVOF
ALBEMARLE SOUND.
SAID COLD FRONT SLOWS ITS SOUTHERLY MOVEMENT MON NITE AND TUESDAY AS
YET ANOTHER IN A SERIES OF S/W RIDES NE ALONG THE BOUNDARY. THIS
SCENARIO WILL LIKELY KEEP THE PCPN CHCS GOING INTO TUESDAY. ONE
CAVEAT TO THE FORECAST IS THE COLDER AIR COMING IN FROM THE NORTH
LATE MONDAY NIGHT. AS TEMPS FALL TO NEAR FREEZING...CRITICAL
THICKNESSES SUPPORTS SOME WET SNOW FLAKES MIXING IN WITH THE RAIN
ACROSS NORTHERN MOST COUNTYS...SO HAVE INTRODUCED A RAIN/SNOW MIX
LATE MON NIGHT FROM LKU-SBY. RAIN ELSEWHERE WITH LOWS IN THE
M30S-M40S. FRONT SLOWLY MOVES OFF THE CAROLINA COAST LATE TUESDAY
WITH CAA SETTING IN. STILL A CHC FOR RAIN WITH HIGHS FROM 40 NORTH
TO M50S SOUTH.
NEXT CANADIAN HIGH PRESSURE BUILDS INTO THE AREA WED AND THURS.
THE GFS SHOWS ANOTHER WAVE OF LOW PRESSURE PROGGED TO DEVELOP ALONG
THE STALLED FRONTAL BOUNDARY ACROSS SERN STATES BY MID WEEK WITH
MOISTURE FROM THIS SYSTEM STAYING JUST SOUTH OF AKQ FA. THE 12Z
ECMWF PUSHES THE COASTAL SYSTEM FURTHER OFFSHORE WITH HIGH PRESSURE
DOMINATING THE ENTIRE REGION. WILL TREND THE DAY 6 AND 7 FORECAST AS
DRY AND COLDER. HIGHS BOTH DAYS IN THE M30S-M40S. LOWS 20-30.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
STILL SOME IFR EARLY THIS AFTERNOON MAINLY NEAR KRIC. LOOKING AT
THE RAP AND NAM WOULD EXPECT MOST AREAS TO LIFT TO MVFR OR VFR
CEILINGS DURING THE AFTERNOON. THERE IS A WEAK SHORTWAVE CROSSING
THE AREA WHICH MAY BRING SOME SHOWERS TO SBY. OVERNIGHT TONIGHT
WINDS KEEP UP AROUND 10 KTS SO EVEN WITH VERY MOIST AIR BELIEVE IT
WILL BE MAINLY STRATUS THAT FORMS. BROUGHT ALL SITES BACK DOWN TO
IFR CEILINGS BUT HELD MOST VSBYS IN THE MVFR RANGE. STILL IN THE
HUMID AIR MASS ON FRIDAY BUT WITH AN APPROACHING FRONT SHOULD GET
CLOUDS BACK TO VFR RANGE BY LATE MORNING AT ALL LOCATIONS.
FRONT PUSHES THROUGH THE AREA FRIDAY NIGHT INTO SATURDAY WITH
PLENTY OF RAIN AND WIDESPREAD IFR CONDITIONS BEHIND THE FRONT. BY
SATURDAY NIGHT EXPECT SOME CLEARING WITH VFR CONDITIONS RETURNING.
NEXT WAVE OF LOW PRESSURE WILL MOVE BY ON SUNDAY WITH MORE
WIDESPREAD IFR CONDITIONS AND WITH A GREATER PROBABILITY FOR MIXED
PRECIP AT KRIC SUNDAY.
&&
.MARINE...
WARM FRONT HAS LIFTED N OF THE AREA TODAY WITH A S FLOW ACROSS THE
WATERS. WINDS PROGGED TO REMAIN BLO SCA LEVELS THROUGH FRI...HOWEVER
WNA SUGGESTS SEAS OUT NEAR 20 NM FLURT WITH 5 FT FRI. GIVEN WNA
SEEMS TO RUN HIGH IN A S FLOW...CONFIDENCE NOT HIGH ENOUGH TO PUT
OUT A MARGINAL SCA FOR SEAS OUT NEAR 20 NM SO NO HEADLINES EXPECTED
IN SHORT TERM.
MODELS CONTINUE TO ADVERTISE A STRONG CAA SURGE BEHIND A COLD FRONT
LATE FRI NIGHT AND SATURDAY. DESPITE THIS BEING A LATE 3RD / 4TH
PERIOD EVENT...CONFIDENCE HIGH ENOUGH TO HOIST SCA HEADLINES FOR THE
CHES BAY / LOWER JAMES RIVER / COASTAL WATERS LATE FRI NIGHT AND
SAT. WENT WITH A 00Z STARTING TIME FOR THE CURRITUCK SOUND AS THE
FLOW AROUND A WAVE OF LOW PRESSURE INCREASES THE GRADIENT ACROSS NC.
SEAS 4-5 FT ALL AREAS BY SAT...THEN 5-6 FT THEREAFTER. HELD OFF ON
ANY HEADLINES FOR THE REST OF THE RIVERS AS THAT SEEMS TO BE A 4TH
PERIOD HEADLINE.
SCA`S WILL LIKELY BE NEEDED THROUGH THE WEEKEND...ESPECIALLY ACROSS
THE COASTAL AREAS AS A PERSISTANT NE FLOW WILL KEEP SEAS AOA 5 FT
INTO EARLY NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
GIVEN THE ASTRONOMICAL TIMING OF THE EVENT...PREDICTED TIDES AND
LEVELS ARE PROGGED TO REMAIN BLO ANY CRITICAL THRESHOLDS THROUGH THE
WEEKEND.
&&
.CLIMATE...
RECORD HIGH TEMPERATURES FRIDAY (12/6)...
RIC 81 IN 1998
ORF 79 IN 1998
SBY 77 IN 1998
ECG 80 IN 1998
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 AM TO 4 PM EST SATURDAY FOR
ANZ630>632-634-650-652.
SMALL CRAFT ADVISORY FROM 7 PM FRIDAY TO 4 PM EST SATURDAY FOR
ANZ633.
SMALL CRAFT ADVISORY FROM 5 AM TO 4 PM EST SATURDAY FOR ANZ638-
654-656-658.
&&
$$
SYNOPSIS...JDM
NEAR TERM...JDM
SHORT TERM...BMD/JDM
LONG TERM...MPR
AVIATION...LKB/JAB
MARINE...MPR
TIDES/COASTAL FLOODING...MPR
CLIMATE...AKQ
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
409 PM EST THU DEC 5 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS OFF THE COAST THROUGH TONIGHT. A SLOW
MOVING COLD FRONT IS EXPECTED TO MOVE INTO THE AREA BY MID DAY
FRIDAY...FOLLOWED BY A PERIOD OF UNSETTLED WEATHER THROUGH EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
MILD S-SW FLOW CONTINUES ACROSS THE REGION INTO TONIGHT...WITH SFC
HIGH PRESSURE SITUATED OFF THE COAST. ABUNDANT LOW-LEVEL MOISTURE
IN PLACE TONIGHT (DEW PTS IN THE 50S TO AROUND 60) WILL ALLOW
CLOUDS TO REMAIN PLENTIFUL...WITH PATCHY DENSE FOG POSSIBLE AGAIN
ESPECIALLY ALONG THE COAST AND OVER THE WATERS. LATEST RADAR
COMPOSITE SHOWS A BATCH OF SHOWERS MOVING EAST AND OFF THE LOWER
MD EASTERN SHORE. MEANWHILE...ANOTHER BATCH OF SHOWERS IS PUSHING
EAST ACROSS SOUTHERN VA AND NE NC. THESE SHOWERS WILL CONTINUE TO
MOVE EAST THROUGH THE EVENING HOURS AND WILL CARRY CHC POPS
(30-40%) DURING THIS TIME. A COLD FRONT WILL CONTINUE TO MOVE
EASTWARD FROM THE OHIO VALLEY AND GETS HUNG UP ALONG THE SPINE OF
THE APPALACHIANS LATE TONIGHT INTO FRI MORNING. THIS IS DUE TO A
BLOCKING PATTERN DEVELOPING...WHERE A STRONG ARCTIC HIGH IS
DIGGING INTO THE NCTRL U.S. AND ANOTHER HIGH IN THE WRN ATLANTIC
IS PREVENTING THE COLD FRONT FROM PROGRESSING EWD. ONCE ANY LIGHT
SHOWERS END THIS EVENING...A DRY PERIOD IS ANTICIPATED OVERNIGHT.
MOISTURE AND WEAK SHORTWAVE ENERGY THEN RIDES ALONG THE FRONT FROM
SW TO NE AND MAY BRING PCPN BACK INTO FAR NW PORTIONS OF THE FA
TOWARD DAYBREAK. MILD TONIGHT WITH LOWS IN THE UPR 50S TO LOW 60S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
THE COLD FRONT TO THE NORTHWEST WILL EVENTUALLY START TO SAG
SOUTHWARD BY FRIDAY AFTERNOON. AHEAD OF THE BOUNDARY...SW FLOW
WILL ALLOW MILD WX TO CONTINUE AND DRY CONDITIONS TO CONTINUE.
ALONG AND NORTH OF THE BOUNDARY...AN EXPECTING STEADIER PCPN TO
ARRIVE ACROSS NORTHERN AREAS...ESPECIALLY IN THE AFTERNOON. AS FAR
AS POPS GO...HAVE LIKELY POPS (60%) SPREADING SOUTHWARD TO ALONG A
FLUVANNA TO HANOVER TO DORCHESTER MD LINE BY LATE FRIDAY
AFTERNOON. FARTHER SOUTH...WILL KEEP THE FORECAST DRY MAINLY ALONG
AND SOUTH OF VA HWY 58. CONTINUED WAA ADVECTION SOUTH OF THE
FRONT AND FAVORABLE MIXING WILL HELP BOOST HIGH TEMPS WELL ABOVE
NORMAL ON FRI...ESPECIALLY OVER SRN AREAS WHERE TEMPS COULD REACH
THE MID-UPPER 70S. FOR NW AREAS...TEMPS MAY ONLY BE IN THE LOW-
MID 60S DEPENDING ON WHERE LOW CLOUDS AND PRECIP OCCUR. THE COLD
FRONT SWEEPS THROUGH THE REST OF THE FA FRI NIGHT AND MOVES SOUTH
OF THE AREA SAT MORNING. PRECIPITATION IS EXPECTED TO BECOME MORE
WIDESPREAD AND STEADY OVERNIGHT FRI. LOW TEMPS WILL BE TRICKY
DEPENDING ON HOW FAST THE POST-FRONTAL ARCTIC AIR CAN MOVE INTO
THE REGION AND WHEN WINDS TURN TO THE NORTHWEST/NORTH. AM
CURRENTLY ANTICIPATING A CONTRAST WITH LOWS IN THE UPPER 30S/LOWER
40S NW TO LOW/MID 50S FAR SE.
SATURDAY...
THE AFOREMENTIONED COLD FRONT STALLS OUT ACROSS THE SERN U.S. AS
ARCTIC HIGH PRESSURE EXPANDS EWD FROM THE OHIO VALLEY AND INTO THE
NORTHEAST. N-NE SFC WINDS WILL CONTINUE TO FUNNEL COLDER AIR INTO
THE MID ATLANTIC REGION THROUGH SAT WITH HIGHS EITHER HOLDING
STEADY OR ONLY RISING A COUPLE OF DEGREES FROM THEIR MORNING LOWS.
HIGHS AROUND 40 NW TO THE LOW/MID 50S FAR SE. THE QUESTION THAT
STILL REMAINS IS JUST HOW MUCH PRECIP LINGERS ACROSS THE LOCAL
AREA ON SATURDAY. ATTM...THE ECMWF AND GFS MODELS STILL FAVOR
LIGHT RAIN LINGERING ALONG AND SOUTH OF A FARMVILLE-RICHMOND-
SALISBURY LINE IN THE MORNING...THEN SHIFTING INTO JUST FAR
SOUTHERN VA AND NE NC IN THE AFTERNOON. THE NAM/SREF SOLUTIONS NOT
ONLY DRIVE THE SFC COLD FRONT A LITTLE FARTHER SOUTH BUT THEY
FLATTEN THE FRONT INTO A MORE WEST TO EAST ORIENTATION...WHICH
SUPPORTS LESS PRECIPITATION SAT AFTN. CONTINUE TO FAVOR THE PRECIP
GETTING HUNG UP NEAR SE COASTAL AREAS AND BEING SLOWER TO EXIT THE
REGION CONSIDERING THE GIVEN POSITION/STRENGTH OF THE WRN ATLANTIC
RIDGE. WILL KEEP BEST PRECIP CHANCES ACROSS THE SERN HALF OF THE
FA THROUGHOUT THE DAY.
SATURDAY NIGHT...
MODELS ARE IN GENERAL AGREEMENT WITH LAYING THE FRONTAL BOUNDARY
INTO A MORE FLAT W-E ORIENTATION SAT NIGHT...THEN PULLING IT BACK
UP THE APPALACHIANS ALMOST LIKE A RETROGRADING LEE TROUGH.
SHORTWAVE ENERGY MOVING UP THIS BOUNDARY FROM THE TN VALLEY IS
EXPECTED TO ENHANCE AND SPREAD PRECIPITATION BACK INTO THE REGION
FROM THE SOUTH/SOUTHWEST OVERNIGHT. MEANWHILE...A COLD AIR WEDGE IS
BEGINNING TO TAKE FORM AS COLD ARCTIC AIR FILTERS INTO THE REGION
FROM THE N/NE. THE COMBINATION OF WARMER AIR IN THE SOUTHEAST
VERSUS THE COLDER AIR TO THE NORTH WILL MAKE FOR A TRICKY
PRECIP-TYPE FORECAST. MODEL DISCREPANCIES REGARDING PRECIP
PLACEMENT AND TIMING ARE DIFFERENT ENOUGH TO MAKE IT DIFFICULT TO
DETERMINE WHERE RAINFALL WILL TRANSITION TO SLEET AND/OR FREEZING
RAIN. AT THIS TIME...THE GFS/ECMWF ARE THE MOST PROGRESSIVE IN
PUSHING THE PRECIP NWD OVERNIGHT. THE NAM HAS MORE OF A DRY LOOK
TO IT...NOT BRINGING PRECIP BACK INTO SW PORTIONS OF THE FA UNTIL
AROUND 12Z SUN. THIS DELAY IS ALSO RESULTING IN A COLDER
TEMPERATURE BIAS OVER NWRN AREAS. THE SREF SPLITS THE DIFFERENCE
BTWN THE FAST GFS/ECMWF AND THE SLOWER/COLDER NAM. USING THICKNESS
HEIGHTS AND WET BULB ZERO TEMPS TO DETERMINE A GENERAL P-TYPE...
HAVE INTRODUCED SOME FREEZING RAIN AND SLEET INTO NW PORTIONS OF
THE FA EARLY SUNDAY MORNING. A MIX OF RAIN AND FREEZING RAIN WILL
BE POSSIBLE EAST OF I-95 FROM EMPORIA TO NEW KENT COUNTY INTO THE
NORTHERN NECK DURING THIS TIME. FARTHER EAST...ALL RAIN IS
EXPECTED SATURDAY NIGHT WITH THE LOWER MD EASTERN SHORE PROBABLY
REAMINING FREE OF PRECIP UNTIL AFTER 12Z SAT. LOW TEMPS ARE EXPECTED
TO BE BELOW FREEZING NE OF A LINE FROM EMPORIA TO NEW KENT TO THE
INTERIOR LOWER MD EASTER SHORE...AND IN THE MID 30S TO NEAR 40 SOUTH
AND SE OF THIS LINE.
THE CHALLENGING FORECAST CONTINUES INTO SUNDAY WHEN OVERRUNNING
PRECIP CONTINUES TO OVERSPREAD THE COLD NEAR-SURFACE AIR. MODEL
CONSENSUS FOR SUNDAY SHOWS A LITTLE BIT COLDER TEMPS THAN WHAT HAS
BEEN PREVIOUSLY EXPECTED WITHIN THE CAD SETUP...ESPECIALLY THE NAM
AND GFS. THE COLDER TREND MEANS THERE IS A POSSIBILITY FOR FROZEN
PRECIP TO HOLD ON LONGER ALONG/WEST OF THE I-95 CORRIDOR...AND
THEREFORE SUGGESTING A HIGHER POSSIBILITY OF WINTER WX HEADLINES
ACROSS THE AREA. IF THE ATMOSPHERE DOES IN FACT START OUT
COLDER...THAN THERE COULD BE MORE SNOW/SLEET THAN FIRST THOUGHT
ACROSS THE NW AS WELL BEFORE A CHANGEOVER TO FREEZING RAIN.
BECAUSE OF THE UNCERTAINTIES WITH P-TYPES AND DURATION OF FROZEN
PRECIP...WILL NOT GET TOO SPECIFIC WITH THE FORECAST JUST YET.
HAVE CONTINUED THE TREND OF SHOWING THE POSSIBILITY OF FROZEN
PRECIP ON SUNDAY...ESPECIALLY THROUGH EARLY AFTERNOON...ALONG AND
NORTH OF A LUNENBURG TO TRI-CITIES TO NORTHERN NECK TO SALISBURY
LINE. HIGHS SUNDAY WILL RANGE FROM THE LOW/MID 30S WEST TO THE LOW
50S ALONG THE SE COAST.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
DUE TO THE 12Z MODELS COLDER AND SLOWER WITH ONSET OF THE EVENT
SUNDAY...BUFKIT DATA NOW SUPPORTS A CONTINUATION OF P-TYPE ISSUES
ACROSS NWRN MOST COUNTYS THROUGH SUNDAY EVENING AS THE WEDGE WILL
BE LOCKED IN PLACE. SO WILL CONTINUE THE FZ RAIN FOR LOUISA/
FLUVANNA/WESTERN GOOCHLAND AND WESTERN CAROLINA COUNTY THROUGH
MIDNIGHT. OTW...RAIN CONTINUES ACROSS THE FA WITH STEADY TEMPS
MOST OF THE NIGHT...SLOWLY RISING AFTER 08Z AS A WEAK WAVE OF LOW
PRESSURE PULLS SOME OCEANIC AIR INLAND.
FIRST WAVE OF LOW PRESSURE MOVES NE OF FA MON MORNING WITH MODELS
INDICATING A SERIES OF WEAK WAVES MOVING NE AHEAD OF THE NEXT COLD
FRONT THAT WILL CROSS THE REGION LATE MONDAY AFTERNOON AND NIGHT.
ENOUGH MOISTURE PROGGED TO CONTINUE THE RAIN CHCS ACROSS THE AREA
MON. MUCH MILDER AS THE FLOW BECOMES SW BUT THE COLD FRONTAL PASSAGE
RESULTS IN ANOTHER TRICKY TEMP FORECAST. EXPECT A WIDE RANGE IN
TEMPS AS RESIDUAL WEDGING LEADS TO TEMPS HOLDING AROUND 50 NORTHERN
MOST COUNTYS...WITH MUCH MILDER AIR (AND MAYBE SOME PARTIAL SUN)
RESULTING IN TEMPS WARMING INTO THE 60S AND POSSIBLY NEAR 70 IVOF
ALBEMARLE SOUND.
SAID COLD FRONT SLOWS ITS SOUTHERLY MOVEMENT MON NITE AND TUESDAY AS
YET ANOTHER IN A SERIES OF S/W RIDES NE ALONG THE BOUNDARY. THIS
SCENARIO WILL LIKELY KEEP THE PCPN CHCS GOING INTO TUESDAY. ONE
CAVEAT TO THE FORECAST IS THE COLDER AIR COMING IN FROM THE NORTH
LATE MONDAY NIGHT. AS TEMPS FALL TO NEAR FREEZING...CRITICAL
THICKNESSES SUPPORTS SOME WET SNOW FLAKES MIXING IN WITH THE RAIN
ACROSS NORTHERN MOST COUNTYS...SO HAVE INTRODUCED A RAIN/SNOW MIX
LATE MON NIGHT FROM LKU-SBY. RAIN ELSEWHERE WITH LOWS IN THE
M30S-M40S. FRONT SLOWLY MOVES OFF THE CAROLINA COAST LATE TUESDAY
WITH CAA SETTING IN. STILL A CHC FOR RAIN WITH HIGHS FROM 40 NORTH
TO M50S SOUTH.
NEXT CANADIAN HIGH PRESSURE BUILDS INTO THE AREA WED AND THURS.
THE GFS SHOWS ANOTHER WAVE OF LOW PRESSURE PROGGED TO DEVELOP ALONG
THE STALLED FRONTAL BOUNDARY ACROSS SERN STATES BY MID WEEK WITH
MOISTURE FROM THIS SYSTEM STAYING JUST SOUTH OF AKQ FA. THE 12Z
ECMWF PUSHES THE COASTAL SYSTEM FURTHER OFFSHORE WITH HIGH PRESSURE
DOMINATING THE ENTIRE REGION. WILL TREND THE DAY 6 AND 7 FORECAST AS
DRY AND COLDER. HIGHS BOTH DAYS IN THE M30S-M40S. LOWS 20-30.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
STILL SOME IFR EARLY THIS AFTERNOON MAINLY NEAR KRIC. LOOKING AT
THE RAP AND NAM WOULD EXPECT MOST AREAS TO LIFT TO MVFR OR VFR
CEILINGS DURING THE AFTERNOON. THERE IS A WEAK SHORTWAVE CROSSING
THE AREA WHICH MAY BRING SOME SHOWERS TO SBY. OVERNIGHT TONIGHT
WINDS KEEP UP AROUND 10 KTS SO EVEN WITH VERY MOIST AIR BELIEVE IT
WILL BE MAINLY STRATUS THAT FORMS. BROUGHT ALL SITES BACK DOWN TO
IFR CEILINGS BUT HELD MOST VSBYS IN THE MVFR RANGE. STILL IN THE
HUMID AIR MASS ON FRIDAY BUT WITH AN APPROACHING FRONT SHOULD GET
CLOUDS BACK TO VFR RANGE BY LATE MORNING AT ALL LOCATIONS.
FRONT PUSHES THROUGH THE AREA FRIDAY NIGHT INTO SATURDAY WITH
PLENTY OF RAIN AND WIDESPREAD IFR CONDITIONS BEHIND THE FRONT. BY
SATURDAY NIGHT EXPECT SOME CLEARING WITH VFR CONDITIONS RETURNING.
NEXT WAVE OF LOW PRESSURE WILL MOVE BY ON SUNDAY WITH MORE
WIDESPREAD IFR CONDITIONS AND WITH A GREATER PROBABILITY FOR MIXED
PRECIP AT KRIC SUNDAY.
&&
.MARINE...
WARM FRONT HAS LIFTED N OF THE AREA TODAY WITH A S FLOW ACROSS THE
WATERS. WINDS PROGGED TO REMAIN BLO SCA LEVELS THROUGH FRI...HOWEVER
WNA SUGGESTS SEAS OUT NEAR 20 NM FLURT WITH 5 FT FRI. GIVEN WNA
SEEMS TO RUN HIGH IN A S FLOW...CONFIDENCE NOT HIGH ENOUGH TO PUT
OUT A MARGINAL SCA FOR SEAS OUT NEAR 20 NM SO NO HEADLINES EXPECTED
IN SHORT TERM.
MODELS CONTINUE TO ADVERTISE A STRONG CAA SURGE BEHIND A COLD FRONT
LATE FRI NIGHT AND SATURDAY. DESPITE THIS BEING A LATE 3RD / 4TH
PERIOD EVENT...CONFIDENCE HIGH ENOUGH TO HOIST SCA HEADLINES FOR THE
CHES BAY / LOWER JAMES RIVER / COASTAL WATERS LATE FRI NIGHT AND
SAT. WENT WITH A 00Z STARTING TIME FOR THE CURRITUCK SOUND AS THE
FLOW AROUND A WAVE OF LOW PRESSURE INCREASES THE GRADIENT ACROSS NC.
SEAS 4-5 FT ALL AREAS BY SAT...THEN 5-6 FT THEREAFTER. HELD OFF ON
ANY HEADLINES FOR THE REST OF THE RIVERS AS THAT SEEMS TO BE A 4TH
PERIOD HEADLINE.
SCA`S WILL LIKELY BE NEEDED THROUGH THE WEEKEND...ESPECIALLY ACROSS
THE COASTAL AREAS AS A PERSISTANT NE FLOW WILL KEEP SEAS AOA 5 FT
INTO EARLY NEXT WEEK.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 AM TO 4 PM EST SATURDAY FOR
ANZ630>632-634-650-652.
SMALL CRAFT ADVISORY FROM 7 PM FRIDAY TO 4 PM EST SATURDAY FOR
ANZ633.
SMALL CRAFT ADVISORY FROM 5 AM TO 4 PM EST SATURDAY FOR ANZ638-
654-656-658.
&&
$$
SYNOPSIS...JDM
NEAR TERM...JDM
SHORT TERM...BMD/JDM
LONG TERM...MPR
AVIATION...LKB/JAB
MARINE...MPR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1242 PM EST THU DEC 5 2013
.UPDATE...
ISSUED AT 1036 AM EST THU DEC 5 2013
...LAKE EFFECT SNOW WARNING NOW UP FOR NORTHERN HOUGHTON COUNTY...
SIGNIFICANT LK EFFECT AND BLOWING SNOW HAS DEVELOPED OVER THE
KEWEENAW. VIS SATELLITE SHOWS TYPICAL ENHANCED BAND OF SNOW
DEVELOPING OFF THE TIP OF BAYFIELD PENINSULA STREAMING INTO THE
VCNTY OF HOUGHTON AND HANCOCK. THINK THIS SNOW BAND RECEIVED
INITIAL BOOST FROM FORCING MOVING ACROSS BRINGING LGT SNOW TO
REST OF WESTERN UPR MICHIGAN. OVERWATER INSTABILITY AND DEPTH OF
LAKE CONVECTIVE LAYER INCREASE THROUGH THE DAY SO THE FAVORABLE
LAKE EFFECT SETUP WILL ONLY BECOME MORE SO THROUGH THE AFTN. EXPECT
THE HEAVY LK EFFECT SNOW TO PERSIST BEFORE SHIFTING/RE-ORIENTING
LATER THIS AFTN INTO EARLY THIS EVENING AS SECONDARY TROUGH MOVING
THROUGH VEERS WINDS TO MORE NW...LIMITING THE PERSISTENT CONVERGENCE
AREA. BASED ON CURRENT TRENDS AND HIGH RES MODEL OUTPUT FOR REST OF
DAY AND WINDS UPSTREAM...ISSUED A LAKE EFFECT SNOW WARNING FOR
NORTHERN HOUGHTON COUNTY AS THAT IS WHERE THE HEAVIER BAND OF SNOW
WILL OCCUR THROUGH THE DAY.
TOTAL SNOW AMOUNTS MAY EXCEED 10 INCHES IF THE BAND STAYS PUT...BUT
THAT IS ALWAYS A CHALLENGE TO SAY IF THAT WILL OCCUR. SNOW RATES
WITHIN THE HEAVIER SNOW BAND WILL BE OVER 1 INCH PER HOUR. SNOW WILL
BE HARD TO MEASURE DUE TO STRONG WINDS BUT THAT ALSO RESULTS IN VERY
POOR VSBY AS SEEN ON WEB CAMS THIS MORNING AND CMX BEING LESS THAN
1/4SM AT TIMES.
WARNING WILL GO THROUGH 03Z WHEN SHIFTING WINDS SHOULD RE-ORIENT THE
HEAVIER SNOW AREAS. VERY LIKELY THIS MAY OCCUR EARLIER THAN 03Z BUT
WANTED TO GIVE EXTRA WIGGLE ROOM AT THE END OF THE WARNING. BEYOND
03Z THE LK EFFECT ADVY KICKS BACK IN. NO CHANGES TO KEWEENAW COUNTY
ADVY AS HEAVIER SNOW SHOWERS WILL FOCUS MORE TO THE SOUTH OF THAT
AREA TODAY. OTHERWISE...BOOSTED POPS FOR NEXT FEW HOURS AWAY FM
KEWEENAW AS LGT SNOW SHOWERS MOVE ACROSS WITH SHALLOW DEPTH
DISTURBANCE. EVENTUALLY THOUGH...EXPECT SNOW TO TAPER OFF/END
LEAVING JUST PERSISTENT FALLING TEMPS AND LOWERING WIND
CHILLS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 504 AM EST THU DEC 5 2013
CONTINUED THE LAKE EFFECT SNOW ADVISORY FOR THE KEWEENAW WHICH WAS
EXTENDED THROUGH SUNDAY MORNING.
RADAR AND SURFACE OBSERVATIONS THIS MORNING ARE ONLY SHOWING A FEW
LINGERING SNOW SHOWERS OVER CENTRAL PORTIONS OF THE UPPER PENINSULA
WITH WINDS BEGINNING TO GUST OUT OF THE SOUTHWEST TO NEARLY 30MPH.
ALSO A WIDE RANGE OF TEMPERATURES ARE BEING DISPLAYED ACROSS THE CWA
WITH IWD AROUND 19F WILE NEWBERRY IS AROUND 36F. THE COOL DOWN IS
EXPECTED TO CONTINUE THROUGH THE DAY.
TODAY AND TONIGHT....LOW PRESSURE CENTERED OVER UPPER MICHIGAN AND
LAKE SUPERIOR EARLY THIS MORNING...WHILE A COLD FRONT WHILE A COLD
FRONT STRETCHES SOUTH AND WESTWARD FROM NORTH CENTRAL WI TO
SOUTHEAST MN AS OF 06Z. THE LOW IS EXPECTED TO CONTINUE
NORTHEASTWARD...PUSHING INTO ONTARIO BY DAY BREAK TODAY. AS THIS
HAPPENS THE COLD FRONT WILL HAVE PASSED THROUGH ALLOWING
TEMPERATURES TO DROP SIGNIFICANTLY ACROSS THE CWA. THIS WILL ALLOW
ANY LIQUID REMAINING ON THE ROADWAYS TO REFREEZE ALLOWING TRAVEL TO
CONTINUE TO BE SLIPPERY ONCE AGAIN...THEREFORE...HAVE ISSUED A SPS
TO DRAW ATTENTION TO THIS POTENTIAL HAZARD. THE POSITIVE SIDE OF
THIS FORECAST PERIOD IS THAT THE MIXED PRECIPITATION HAS MOVED OUT
OF THE AREA...LEAVING TEMPERATURES ALOFT COLD ENOUGH TO KEEP
PRECIPITATION IN THE FORM OF SNOW AS THE UPPER LEVEL TROUGH
ASSOCIATED WITH THE SURFACE LOW PUSHES OVERHEAD. FOR THE
DETAILS...WINDS WILL BECOME FAIRLY STRONG OUT OF THE WEST AS THE
SURFACE CONTINUES LIFTS NORTHEASTWARD FROM NORTHERN LAKE SUPERIOR AS
OF 12Z/05 TO NEAR JAMES BAY BY 18Z/05...WHERE IT WILL BECOME NEARLY
STATIONARY.
WITH THE COLD AIR ADVECTION ACROSS THE RELATIVELY WARM WATERS OF
LAKES SUPERIOR IN THE WAKE OF THE LOW...LAKE EFFECT SNOW WILL BECOME
A CONCERN...ESPECIALLY FOR WESTERLY WIND FAVORED SNOW BELTS OF THE
UPPER PENINSULA. AT 850MB THE COLDER TEMPERATURES REALLY START TO
BUILD INTO THE AREA BY 12Z/05 WITH MUCH OF THE WESTERN HALF OF THE
U.P. UNDER -10C TO -14C 850MB TEMPS. THIS WILL AGAIN BE FAVORABLE
FOR LAKE EFFECT SNOW DEVELOPMENT AS LAKE SURFACE TEMPERATURES ARE
CURRENTLY RUNNING AROUND 4C TO 5C. TEMPERATURE INVERSION HEIGHTS
AROUND 12Z ARE PROGGED TO BE AROUND 7KFT WITH MOISTURE AND LIFT
BEGINNING TO BE COLLOCATED IN THE FAVORED DGZ...MAINLY OVER THE
KEWEENAW PENINSULA. EVEN COLDER TEMPERATURES ARE EXPECTED TO PUSH IN
AT 850MB BY EARLY AFTERNOON AROUND 18Z WITH 850MB TEMPERATURES
RANGING FROM -14C OVER THE EAST TO -17 OVER THE WEST AND INVERSION
HEIGHTS LIFT TO AROUND 8KFT. THIS HELPS TO PLACE A GREATER DEAL OF
MOISTURE AN FORCING IN THE DGZ...ALLOWING FOR BETTER SNOW GROWTH
OVER THE KEWEENAW PENINSULA. REALLY NOT MANY CHANGES OCCUR FROM
18Z/05 THROUGH 06Z/06...EXCEPT FOR EVEN COLDER AIR PRESSES INTO THE
UPPER PENINSULA AT 850MB...WITH TEMPERATURES AT THAT LEVEL DROPPING
TO -20C OVER THE WESTERN U.P. SLIGHTLY DRYER AIR BUILDS IN ALOFT BY
06Z WHICH WILL LIKELY HELP TO REDUCE THE INTENSITY OF THE LAKE
EFFECT SNOW ACROSS THE KEWEENAW.
AWAY FROM THE KEWEENAW PENINSULA...THE MAIN ISSUE DURING THIS ENTIRE
TIME FRAME WILL BE MUCH COLDER TEMPERATURES BUILDING INTO THE
REGION. THE THICK CLOUD BANK THAT HAS LINGERED OVER MUCH OF THE AREA
OVER THE PAST COUPLE OF DAYS WILL TRY TO FINALLY BREAK UP...MAINLY
AWAY FROM LAKE SUPERIOR. THIS CLEARING ALONG WITH THE AFOREMENTIONED
COLDER 850MB TEMPERATURES WILL ALLOW OVERNIGHT LOWS TO DROP INTO THE
SINGLE DIGITS ABOVE ZERO OVER MUCH OF THE U.P. WITH THE INLAND WEST
AREAS POSSIBLY DROPPING INTO SINGLE DIGITS BELOW ZERO. THESE BELOW
ZERO TEMPERATURES COUPLED WITH WEST WINDS CLOSE TO 10 MPH OVERNIGHT
WILL MAKE WIND CHILL READINGS FALL TO 15 TO 20 BELOW ZERO. THIS
WOULD BE MARGINAL FOR A WIND CHILL ADVISORY...BUT THIS MAY BE NEEDED
BY THE AFTERNOON UPDATE.
ALSO...AWAY FROM THE KEWEENAW DECIDED TO ISSUE A GALE WARNING FOR
NORTHWESTERN LAKE MICHIGAN AS TIGHT PRESSURE GRADIENT BUILDS OVER
THE AREA ALONG WITH CAA ALLOWING STRONGER WINDS ALOFT TO MIX DOWN TO
THE RELATIVELY WARM SURFACE OF THE LAKE. RUC ANALYSIS SHOWS THE
POTENTIAL FOR 38KT WINDS TO MIX DOWN TO THE SURFACE OF THE LAKE.
ALREADY THIS MORNING THERE WERE A COUPLE OF OBS COMING IN WITH GUSTS
TO 32KTS...WITH THESE GUSTS LIKELY TO INTENSIFY THROUGH THIS
AFTERNOON.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 504 AM EST THU DEC 5 2013
MAIN FCST CONCERNS IN THE LONG TERM INCLUDE TEMPS/LES MAINLY IN THE
W-NW SN BELTS AND THE POTENTIAL FOR ANOTHER LARGER SCALE SN EVENT
EARLY NEXT WEEK. OVERALL TEMPS WL RUN WELL BLO NORMAL MOST OF THE
LONGER TERM WITH ARCTIC AIRMASSES DOMINATING.
FRI INTO SAT...AS THE LO TO THE NE DRIFTS SLOWLY INTO QUEBEC AND
ARCTIC HI PRES SLIDES FM WRN CANADA INTO THE NRN PLAINS...THE STEADY
FLOW OF VERY COLD AIR IS PROGGED TO GRDLY VEER TOWARD THE WNW AND
DIMINISH WITH TIME AS H85 TEMPS FALL SLOWLY TO ARND -17C OVER THE E
AND -21C OVER THE W BY 12Z SAT. THIS TYPICAL WINTER WX REGIME WL
FAVOR NEARLY CONTINUOUS LES IN THE FAVORED SN BELTS. A SHRTWV
TRACKING EWD THRU SRN ONTARIO/NRN LK SUP ON FRI NGT AND ACCOMPANYING
DEEPER MSTR MAY RESULT IN SOME ENHANCEMENT TO THE LES. ALTHOUGH THE
WINDS/BLSN WL BE DIMINISHING GRDLY...EXPECT LES/WINTER WX ADVYS TO
BE IN PLACE FOR THE FAVORED LES BELTS WITH FAVORABLE ALIGNMENT OF
THE LLVL OMEGA WITHIN THE DGZ. WENT HIER THAN MODEL CONSENSUS POPS
FOR LES IN THE FAVORED SN BELTS...USING CLIMATOLOGY GRIDS TO
EVALUATE THE POPS. AS THE LLVL WINDS DIMINISH...LAND BREEZE CNVGC
MAY PLAY A MORE IMPORTANT ROLE IN ENHANCING THE LES BANDS IN SOME
PLACES...WITH AT LEAST LOCALLY HEAVIER SN FALL APRCHG WARNING
CRITERIA. THIS POTENTIAL APPEARS GREATEST NEAR LK SUP E OF GRAND
MARAIS ON FRI NGT. SN/WATER RATIOS WL ALSO LIKELY BE MORE FVRBL FOR
LARGER FLAKES AS THE FLAKE FRACTURING DIMINISHES WITH THE WEAKENING
WINDS. AWAY FM THE FAVORED SN BELTS...THE WX DURING THIS TIME WL BE
VERY COLD BUT DRY. SUB ZERO MIN TEMPS WITH DAYTIME TEMPS STRUGGLING
TO RISE ABV 10F WL THE RULE OVER THE INTERIOR W HALF WITHIN THE LESS
MODIFIED ARCTIC AIR.
SAT NGT/SUN...THE SLOW EWD PUSH OF THE ARCTIC HI CENTER FM THE NRN
PLAINS THRU THE GREAT LKS/SLOWLY BACKING WINDS TO WSW ON SUN WL
CAUSE THE LES TO DIMINISH. THESE SHSN WL LINGER THE LONGEST OVER THE
KEWEENAW...AND EXTNENDED LES ADVY FOR THAT AREA UNTIL 12Z SUN.
DEPENDING ON HOW QUICKLY WAD CLDS SPILL INTO THE UPR LKS ON SUN TO
THE E OF A DEEPENING TROF IN THE PLAINS...TEMPS AT SOME PLACES OVER
THE INTERIOR ON EARLY SUN MRNG MAY FALL INTO THE TEENS BLO ZERO WITH
LGT WINDS UNDER THE ARRIVING SFC HI CENTER.
EXTENDED...NEXT LARGER SCALE PCPN EPISODE IS LIKELY TO ARRIVE ON SUN
NGT INTO EARLY MON. SOME OF THE LONGER TERM MODELS WERE SHOWING A
PHASING OF THE ARCTIC/POLAR BRANCHES WITH A DEEPER SFC LO TRACKING
THRU THE WCENTRAL GREAT LKS. IF THIS SCENARIO WERE TO VERIFY...A
WDSPRD ADVY SN WL BE PSBL OVER MUCH OF THE CWA. BUT THE MORE RECENT
LONGER TERM GUIDANCE APPEARS TO BE SHIFTING TOWARD LESS PHASING/A
WEAKER SFC LO THAT WOULD CAUSE JUST A FEW INCHES...MAINLY OVER THE E
CLOSER TO LO TRACK THRU LOWER MI. SINCE THE TREND HAS BEEN FOR A
WEAKER LO...GUIDANCE IS ALSO INDICATING THE AIRMASS FOLLOWING INTO
THE UPR LKS FOR LATER MON INTO TUE MAY NOT BE AS COLD AS PREVIOUSLY
INDICATED...WITH H85 TEMPS DOWN TO -25C INSTEAD OF -28C OR EVEN
-30C. STILL...LES WOULD BE A GOOD BET IN THE NW WIND SNOW BELTS. A
NUMBER OF THE LONGER TERM MODELS INDICATE A CLIPPER LO PRES MIGHT
TRACK THRU THE UPR LKS ON TUE AND BRING ANOTHER PERIOD OF MORE
WDSPRD -SN. THE CHILLY NW FLOW BTWN THE DEPARTING CLIPPER LO IN
ONTARIO AND HI PRES SINKING INTO THE CENTRAL CONUS WL THEN BRING
ANOTHER ROUND OF LES IN THE FAVORED SN BELTS. FINALLY...SOME OF THE
EXTENDED GUIDANCE IS HINTING THE UPR FLOW WL TREND MORE ZONAL LATER
NEXT WEEK AND BRING A MODERATION TO THE ARCTIC CHILL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1241 PM EST THU DEC 5 2013
AT CMX...STRONG BAND OF LK EFFECT SNOW WILL REMAIN IN THE VCNTY INTO
EARLY THIS EVENING. EXPECT BLO AIRPORT MINS WITHIN THE SNOW BAND AS
VSBY LOWERS TO LESS THAN 1/4SM IN HEAVY SNOW AND BLOWING SNOW AS
WINDS GUST TO OVER 30 KTS AT TIMES. CONDITIONS IMPROVE SLIGHTLY THIS
EVENING...BUT IFR CONDITIONS WILL STAY IN PLACE THROUGH FRIDAY WITH
OCCASIONAL LAKE EFFECT SNOW SHOWERS.
AT IWD AND SAW...WEST WINDS WILL NOT FAVOR MUCH LK EFFECT SNOW
THROUGH THE PERIOD. MVFR CLOUDS OVERHEAD THIS AFTN WILL LIKELY
SCATTER OUT TONIGHT AT SAW BUT SHOULD PERSIST AT IWD. WINDS WILL
DIMINISH BY THIS EVENING AND REMAIN LESS THAN 15 KTS INTO FRIDAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 504 AM EST THU DEC 5 2013
EXPECT W GALES AS HI AS 40-45 KTS TO DEVELOP OVER LAKE SUPERIOR
TODAY AND CONTINUE INTO TONIGHT WITH SHARPENING PRES GRADIENT ON THE
SW FLANK OF LO PRES MOVING NE THRU ONTARIO. FREEZING SPRAY WILL ALSO
DEVELOP AS VERY COLD ARCTIC AIR SPILLS OUT OVER THE LAKE. THERE MAY
BE POCKETS OF HEAVY FREEZING SPRAY TONIGHT. THE W GALES WILL THEN
SLOWLY DIMINISH W-E LATE TONIGHT/FRI AS THE PRES GRADIENT SLOWLY
SLACKENS WITH THE SLOW APPROACH OF HI PRES FROM THE NORTHERN PLAINS.
WINDS WILL TURN TO THE S-SW ON SUN AND DIMINISH UNDER 15 KTS WITH
THE PASSAGE OF THE HI PRES TO THE E. A LO PRES SYSTEM MOVING NE THRU
LOWER MI ON SU NIGHT WILL FOLLOW THE DEPARTING HI. NW GALES AND MORE
FREEZING SPRAY WILL THEN DEVELOP ON MON AS ANOTHER ARCTIC AIRMASS
INVADES THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST
SUNDAY FOR MIZ003.
LAKE EFFECT SNOW WARNING UNTIL 10 PM EST THIS EVENING FOR MIZ003.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST SUNDAY FOR MIZ001.
LAKE SUPERIOR...
GALE WARNING UNTIL 11 AM EST FRIDAY FOR LSZ264>267.
GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ162.
GALE WARNING UNTIL 4 AM EST FRIDAY FOR LSZ263.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ246>248-250-251.
GALE WARNING UNTIL 1 AM EST /MIDNIGHT CST/ FRIDAY FOR LSZ241>245.
LAKE MICHIGAN...
GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LMZ221-248-250.
&&
$$
UPDATE...JLA
SHORT TERM...KEC
LONG TERM...KC
AVIATION...JLA
MARINE...KC
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
404 PM CST THU DEC 5 2013
.SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...AS OF WRITING...COLD
FRONT HAS CLEARED ALL BUT SOUTHERN WEBB COUNTY AND OFFSHORE
MARINE ZONES. MAIN FORECAST CHALLENGES FOR SHORT TERM PERIOD ARE
LIGHT PRECIP AND TEMPS. SHALLOW AND DRY AIRMASS FROM SFC TO H9 IS
CURRENTLY MOVING SOUTH INTO THE AREA WHICH SHOULD LIMIT PRECIP
POTENTIAL FOR THIS AFTERNOON AND EVENING. BY LATE EVENING /AND
ESPECIALLY AFTER MIDNIGHT/ WAA OVER SHALLOW COOL AIRMASS SHOULD
INCREASE RESULTING IN LIGHT DRIZZLE/RAIN DEVELOPING...WITH THE
PRECIP FORECAST REFLECTING A BLEND OF THE HRRR AND TTU 4KM WRF
/GIVEN BETTER MODEL RESOLUTION AND BETTER HANDLING OF SHALLOW
AIRMASS/ THE LIGHT PRECIP SHOULD SHIFT EAST LATE TONIGHT AND
THROUGH FRIDAY MORNING AS H5 S/W DISTURBANCE KICKS EAST AND H85
FRONT DRIFTS INTO THE CWA...WITH THE AFTERNOON AND EVENING HOURS
OF FRIDAY CURRENTLY FORECAST TO REMAIN DRY. UNCERTAINTY EXISTS AS
TO HOW MUCH DRY AIR WILL WORK INTO THE REGION FRIDAY AFTERNOON.
NAM IS THE DRIEST AND EVEN WANTS TO DEVELOP SOME SIGNIFICANT
BREAKS IN THE CLOUD COVER ACROSS THE BRUSH COUNTRY /WITH THE 12Z
ECMWF HINTING AT SOME SUNSHINE AS WELL/. GFS AND CMC ARE MORE
PESSIMISTIC AND KEEP THE CLOUD COVER THROUGH THE DAY. FOR
NOW...WILL GO WITH A BLEND AND INDICATE POSSIBILITY OF AT LEAST A
FEW PEAKS OF SUNSHINE...PRIMARILY ACROSS WESTERN ZONES. WEAK
COASTAL TROUGHING TRIES TO DEVELOP BY LATE FRIDAY NIGHT WHICH
COULD LEAD TO SOME LIGHT PRECIP ACROSS EASTERN HALF OF CWA. TEMPS
FRI NIGHT COULD APPROACH FREEZING ACROSS N/NE ZONES WHICH WOULD
POTENTIALLY ALLOW FOR SOME LIGHT FREEZING DRIZZLE ON ELEVATED
SURFACES. AT THIS TIME...ANY FREEZING DRIZZLE IS EXPECTED TO BE
BRIEF AND ISOLATED IN NATURE. WILL CONTINUE TO MONITOR SITUATION.
TEMPS TONIGHT ARE TRICKY AS EVAPORATIVE COOLING IN LOWEST 100 MB
COULD ALLOW TEMPS TO FALL INTO THE 30S AREAWIDE. FEEL THAT
GREATEST EVAP COOLING WILL BE ACROSS NE ZONES AND THUS HAVE
COOLEST TEMPS DRAWN THERE. HIGHS FRIDAY WILL BE ROUGHLY 25 DEGREES
BELOW NORMAL FOR THIS TIME OF YEAR...BUT COULD POTENTIALLY BE A
LITTLE WARMER THAN FORECAST VALUES IF ANY AFTERNOON SUNSHINE
DEVELOPS. SATURDAY NIGHT LOOKS TO BE COLDER THAN TONIGHT AS
STRONGER CAA OCCURS WITH ALMOST ALL LOCATIONS FALLING INTO AT
LEAST THE MID 30S. WITH CAA ADVECTION OCCURRING FRIDAY
NIGHT...SOME LOCATIONS /ESPECIALLY COASTAL PLAINS AND VICTORIA
REGION/ MAY HAVE WIND CHILL VALUES REACH WIND CHILL ADVISORY
CRITERIA /WIND CHILL VALUES OF 15 TO 25 DEGREES WITH SUSTAINED
WINDS OF AT LEAST 10 MPH/. WILL BE SOMETHING TO TAKE A LOOK WITH
FRIDAY/S FORECAST PACKAGES.
&&
.LONG TERM (SATURDAY THROUGH THURSDAY)...AS A SHORT WAVE TROUGH
MOVES FROM NORTHERN MEXICO SATURDAY AND THROUGH THE OZARKS BY
SUNDAY MORNING...WARM AIR ADVECTION IN THE 925-85H LAYER ALONG WITH
INCREASING ISENTROPIC LIFT WILL PROVIDE A CHANCE OF LIGHT RAIN OVER
THE AREA SATURDAY AND ESPECIALLY SATURDAY NIGHT AS SOUTHERLY FLOW AT
85H INCREASES TO 35-45 KNOTS. AT THE BEGINNING OF SATURDAY...SHALLOW
COLD AIR MASS MAY BE COLD ENOUGH TO PROVIDE A SMALL WINDOW FOR
FREEZING RAIN OR FREEZING DRIZZLE TO OCCUR FROM TILDEN OVER TO
BEEVILLE AND VICTORIA. WITH EXPECTED CLOUD COVER AND LIGHT RAIN
TEMPERATURES WILL NOT MOVE MUCH SATURDAY INTO SATURDAY NIGHT.
THE LOW LEVEL WARM AIR ADVECTION ZONE SHIFTS TO THE EAST ON THE
DAY SUNDAY WITH A POSSIBLE DECREASE IN CLOUD COVER OUT WEST FOR
A SLIGHT WARM UP. BUT THE NEXT STRONG UPPER LOW DIVING INTO THE
PACIFIC NORTHWEST DOWNSTREAM FROM AN IMPRESSIVE RIDGE INTO ALASKA
WILL LEAD TO ANOTHER DISPERSAL OF ARCTIC AIR THAT WILL REACH THE
REGION ON MONDAY. MOISTURE WILL BE SHUNTED TO THE EAST AND A VERY
STRONG OFFSHORE FLOW WILL OCCUR MONDAY NIGHT INTO TUESDAY MORNING.
HIGH PRESSURE SETTLING INTO THE REGION SHOULD LEAD TO FREEZING
TEMPERATURES ACROSS MUCH OF SOUTH TEXAS BY TUESDAY MORNING. THERE
ARE SOME DIFFERENCES IN HOW THE MEDIUM RANGE MODELS HANDLE ENERGY
IN THE SOUTHERN STREAM LATE IN THE PERIOD. ECMWF SHOWS A STRONGER
SHORT WAVE TROUGH MOVING OUT OF MEXICO INTO TEXAS WEDNESDAY AND
THURSDAY THAT WOULD LEAD TO SOME MOISTURE OVERRUNNING THE COLD AIR
AT THE SURFACE AND POSSIBLY INCREASED RAIN CHANCES. BUT FOR NOW WENT
WITH THE OTHER MODELS AND KEPT THE FORECAST DRY FOR WEDNESDAY AND
THURSDAY. SHOWED ONLY A MODEST WARM UP TO THE MID/UPPER 50S BY
THURSDAY.
&&
.MARINE...WIND SPEEDS SHOULD INCREASE THROUGH THE REMAINDER OF THE
AFTERNOON AND EARLY EVENING AS COLD FRONT PUSHES THROUGH. WINDS
MAY ACTUALLY DECREASE IN INTENSITY OVERNIGHT BEFORE BECOMING A
STRONG OFFSHORE FLOW FRIDAY AND THROUGH THE WEEKEND. WAVE HEIGHTS
WILL BUILD SIGNIFICANTLY FRIDAY WITH ADDITIONAL SMALL CRAFT
ADVISORIES LIKELY FRIDAY AND OVER THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 41 44 35 38 35 / 50 60 20 40 50
VICTORIA 36 41 32 36 33 / 60 70 20 50 50
LAREDO 44 51 35 40 36 / 50 30 10 20 20
ALICE 40 44 34 37 34 / 50 50 20 40 40
ROCKPORT 41 45 33 38 37 / 60 70 20 50 50
COTULLA 41 48 32 38 33 / 60 40 10 20 20
KINGSVILLE 41 46 34 38 35 / 50 60 20 40 40
NAVY CORPUS 43 46 35 39 38 / 50 60 20 50 50
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT
ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT
O`CONNOR...COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS
OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA
SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT
ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
&&
$$
RH/79...SHORT TERM
TMT/89...LONG TERM