Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/14/13
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
145 PM EST SAT JAN 12 2013
.SYNOPSIS...
18Z WATER VAPOR AND H4 RAP ANALYSIS SHOW A HIGHLY AMPLIFIED PATTERN
IN PLACE OVER THE CONUS. LUCKILY FOR US...THE WARM AND FAIR WEATHER
SIDE OF THIS AMPLIFICATION RESIDES OVER OUR HEADS...AND WILL
CONTINUE TO DO SO FOR THE REMAINDER OF THE WEEKEND. LARGE SCALE
PATTERN CONSISTS OF DEEP LONGWAVE TROUGHING IN PLACE OVER THE
WESTERN HALF OF THE NATION FOLLOWED DOWNSTREAM BY LONGWAVE RIDGING
EXTENDING FROM THE EASTERN GULF OF MEXICO NORTHWARD ALONG THE ENTIRE
EASTERN SEABOARD. WV IMAGERY CONTINUES TO SHOW AN INTERESTING SPIN /
LEFTOVER MCV PUSHING THROUGH THE RIDGE OFF THE NORTHEAST FL COAST.
THIS VORTICITY CENTER IS LIKELY LEFTOVER FROM CONVECTION TO OUR WEST
DURING THE PAST COUPLE DAYS. THIS FEATURE IS VISUALLY INTERESTING...
BUT WILL HAVE LITTLE IMPACT ON OUR LOCAL WEATHER OTHER THAN SOME
WEAK NVA/ENHANCE SUPPRESSION OVER THE AREA THROUGH THE AFTERNOON.
12Z KTBW SOUNDING PROFILE SHOWS THE INFLUENCE OF THE UPPER RIDGE
WITH A DISTINCT SUBSIDENCE INVERSION ABOVE 850MB. COLUMN IS QUITE
DRY ABOVE THIS LEVEL...BUT SEEING ENOUGH MOISTURE UNDERNEATH TO ONCE
AGAIN FORCE A SCT-BKN SHALLOW CU FIELD OVER LAND AREAS THROUGH EARLY
THIS EVENING.
AT THE SURFACE...HIGH PRESSURE CENTERED OFF THE SOUTHEAST COAST
RIDGES BACK TO THE WEST ALONG OR JUST NORTH OF THE I-10 CORRIDOR.
THIS POSITION CONTINUES TO PROVIDE OUR LOCAL AREA WITH A LIGHT EAST
TO EAST-SOUTHEAST FLOW. THE UNSEASONABLE TEMPERATURES ALSO CONTINUE
WITH MANY LOCATION ALREADY REPORTING READINGS IN THE LOWER 80S. IT
IS QUITE POSSIBLE THAT A FEW MORE RECORD HIGHS WILL BE BROKEN THIS
AFTERNOON.
&&
.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
TONIGHT THROUGH SUNDAY NIGHT...
STACKED RIDGING WILL KEEP THE WEATHER PATTERN UNCHANGED THROUGH THE
REMAINDER OF THE WEEKEND. OVERNIGHT LOWS WILL MAINLY BE IN THE
LOWER/MID 60S AT THE COAST AND MIDDLE 50S TO AROUND 60 INLAND.
DAYTIME HIGHS CLIMB BACK INTO THE LOWER 80S FOR MANY LOCATIONS
SUNDAY AFTERNOON. LOCAL GRADIENT DOES SLACKEN A BIT DURING THE DAY
ON SUNDAY...AND DUE TO THE UNUSUALLY STRONG LAND BASED HEATING...MAY
SEE A FEEBLE SEA-BREEZE DEVELOP DURING THE AFTERNOON...ESPECIALLY
FROM PINELLAS COUNTY NORTHWARD WHERE THE LAND/SEA TEMPERATURE
GRADIENT WILL BE GREATEST. IF THIS WEAK ONSHORE FLOW DOES DEVELOP
THEN THE IMMEDIATE COAST WOULD END UP A FEW DEGREES COOLER.
REGARDLESS WILL BE FORECASTING ABOVE NORMAL TEMPERATURES FOR ALL.
THE UPPER LEVEL RIDGE OVER-TOP THE INFLUX OF LOW LEVEL ATLANTIC
MOISTURE IS A GOOD SETUP FOR AREAS OF FOG TO DEVELOP ONCE AGAIN
DURING THE LATE NIGHT HOURS...SIMILAR TO EARLY THIS MORNING. BEST
CHANCES FOR THE FOG WILL BE INLAND. SHELF WATER TEMPERATURES HAVE
WARMED BY SEVERAL DEGREES DURING THE PAST WEEK RESULTING IN LESS
POTENTIAL FOR ADVECTION SEA FOG. HOWEVER...WILL CONTINUE TO MONITOR
FOR THIS POSSIBILITY...ESPECIALLY ALONG THE NATURE COAST ZONES.
MONDAY/MONDAY NIGHT...
WARM AND GENERALLY DRY CONDITIONS PREVAIL INTO THE FIRST DAY OF THE
NEW WORK WEEK AS STACKED RIDGING WILL REMAIN IN PLACE. WILL BEGIN TO
SEE THE FIRST SIGNS OF THE EVENTUAL BREAK DOWN OF THE RIDGE BY
MONDAY NIGHT INTO TUESDAY AS HEIGHT FALLS BEGIN TO SPREAD ACROSS THE
SOUTHERN PLAINS AND MIDDLE MS VALLEY. THIS PATTERN WILL EVENTUALLY
PUSH THE UPPER RIDGE EASTWARD AND ALLOW A FRONT TO SLIP INTO OUR
REGION...BUT THIS IS NOT UNTIL THE MID-WEEK PERIOD. MORE ON THIS
FRONT IN THE LONG TERM DISCUSSION BELOW.
&&
.LONG TERM (TUESDAY - FRIDAY)...
AN UPPER LEVEL TROUGH REACHES FROM HUDSON BAY TO THE SOUTHWEST U.S.
WITH A FRONT FROM THE GREAT LAKES TO THE WESTERN GULF COAST WHILE
DEEP RIDGING OFF THE EASTERN SEABOARD EXTENDS TO THE EAST GULF AND
CUBA MON NIGHT. THE UPPER TROUGH SLOWLY WORKS EAST TO THE EASTERN
STATES BY WED...SHIFTING THE DEEP RIDGING TO ALONG AND SOUTH OF
LATITUDE 30 NORTH. THE FRONT SAGS ACROSS THE GULF COAST AND SE U.S.
AND PUSHES INTO FL LATE WED. THIS WOULD SUGGEST SOME POSSIBILITY OF
RAINFALL BUT BOTH MOISTURE AND ENERGY ARE LIMITED AND WILL KEEP
THE FORECAST DRY.
THU-FRI...WHILE THE GFS AND ECMWF HAVE BEEN IN FAIRLY GOOD
AGREEMENT THEY NOW BEGIN TO DIVERGE. THE GFS KEEPS BROAD
TROUGHING OVER THE EASTERN U.S. AS A SURFACE HIGH MOVES OVER THE
GULF COASTAL STATES TO THE ATLANTIC. THIS PATTERN WOULD KEEP THE
AREA DRY AND STABLE. THE ECMWF HAS SIMILAR TROUGHING BUT WITH A
CUT-OFF LOW OVER THE SOUTHERN PLAINS THAT MOVES TO THE CENTRAL
GULF COAST WITH AN ASSOCIATED SURFACE LOW THAT TRAILS A COLD FRONT
ACROSS THE CENTRAL AND EASTERN GULF. THIS WOULD SUGGEST SOME
BETTER...BUT LOW...ODDS OF PRECIPITATION. FOR NOW WILL MAINTAIN A
DRY FORECAST.
INITIALLY WARM TEMPERATURES WILL GRADUALLY DECREASE BUT STILL
REMAIN ABOVE NORMAL.
&&
.AVIATION...
SOME CHANCE OF BRIEF MVFR CEILINGS AROUND 3000 FEET THIS
AFTERNOON...BUT MAINLY BROKEN VFR CEILINGS 3500 TO 5000 FEET. FOG
AND LOW CLOUDS DEVELOP 06-09Z WITH MVFR TO IFR POSSIBLE ALL
TERMINALS AND LIFR POSSIBLE LAL AND PGD.
&&
.MARINE...
THE SURFACE RIDGE REMAINS ALIGNED FROM OFF THE SOUTHEAST COAST BACK
WESTWARD ALONG THE I-10 CORRIDOR. THE RIDGE WILL HOLD POSITION
THROUGH TONIGHT AND THEN SLOWLY SETTLE SOUTHWARD LATER SUNDAY INTO
THE EARLY PORTION OF NEXT WEEK. NO MARINE HEADLINES ARE ANTICIPATED
THROUGH THE EARLY PORTION OF THE WEEK. THE NEXT COLD FRONT IS
EXPECTED TO ARRIVE ACROSS THE EASTERN GULF OF MEXICO BY WEDNESDAY OR
WEDNESDAY NIGHT.
&&
.FIRE WEATHER...
SURFACE AND UPPER LEVEL HIGH PRESSURE WILL REMAIN IN CONTROL OF THE
FORECAST AREA THROUGH MONDAY KEEPING OUR WEATHER GENERALLY DRY WITH
ABOVE AVERAGE TEMPERATURES. DESPITE THE WARM DAYTIME TEMPERATURES...
THE SURFACE RIDGE POSITION OFF THE SOUTHEAST COAST WILL PROVIDE A
STEADY INFLUX OF LOW LEVEL ATLANTIC MOISTURE AND PREVENT ANY
WIDESPREAD AREAS OF CRITICALLY LOW RELATIVE HUMIDITY. THE NEXT COLD
FRONT IS NOT ANTICIPATED TO ARRIVE UNTIL LATER WEDNESDAY OR
WEDNESDAY NIGHT. A MORE SEASONABLE AIRMASS IS ANTICIPATED TO ARRIVE
BEHIND THIS FRONT FOR THE LATER PORTION OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 64 81 64 80 / 0 0 10 0
FMY 64 83 62 82 / 0 0 0 0
GIF 59 82 58 82 / 0 0 0 0
SRQ 62 79 60 79 / 0 0 0 0
BKV 57 83 55 81 / 0 0 10 0
SPG 65 79 64 78 / 0 0 0 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
AVIATION...JILLSON
LONG TERM...RUDE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
955 AM EST SAT JAN 12 2013
.UPDATE (REST OF THE WEEKEND)...
15Z WATER VAPOR AND H4 RAP ANALYSIS SHOW A HIGHLY AMPLIFIED PATTERN
IN PLACE OVER THE CONUS THIS MORNING. LUCKILY FOR US...THE WARM AND
FAIR WEATHER SIDE OF THIS AMPLIFICATION RESIDES OVER OUR HEADS...AND
WILL CONTINUE TO DO SO FOR THE REMAINDER OF THE WEEKEND. LARGE SCALE
PATTERN CONSISTS OF DEEP LONGWAVE TROUGHING IN PLACE OVER THE
WESTERN HALF OF THE NATION FOLLOWED DOWNSTREAM BY LONGWAVE RIDGING
EXTENDING FROM THE EASTERN GULF OF MEXICO NORTHWARD ALONG THE ENTIRE
EASTERN SEABOARD. WV IMAGERY SHOWS AN INTERESTING SPIN / LEFTOVER
MCV RUNNING THROUGH THE RIDGE THIS MORNING OVER NORTHERN
FLORIDA...LIKELY LEFTOVER FROM CONVECTION TO OUR WEST DURING THE
PAST COUPLE DAYS. THIS FEATURE IS VISUALLY INTERESTING...BUT WILL
HAVE LITTLE IMPACT ON OUR LOCAL WEATHER OTHER THAN SOME WEAK
NVA/ENHANCE SUPPRESSION OVER THE AREA INTO THE EARLY AFTERNOON. THIS
SUPPRESSION OVER-TOP THE LOW LEVEL MOISTURE MAY HAVE AIDED SOME OF
THE FOG FORMATION EARLIER THIS MORNING...BUT NOW THAT DIURNAL
HEATING HAS COMMENCED...ANY LEFTOVER VISIBILITY RESTRICTIONS WILL
SOON BE A DISTANT MEMORY. 12Z KTBW SOUNDING PROFILE SHOWS THE
INFLUENCE OF THE UPPER RIDGE WITH A DISTINCT SUBSIDENCE INVERSION
ABOVE 850MB THIS MORNING. COLUMN IS QUITE DRY ABOVE THIS LEVEL...BUT
SEEING ENOUGH MOISTURE UNDERNEATH TO ONCE AGAIN FORCE A SCT-BKN
SHALLOW CU FIELD FOR THE AFTERNOON HOURS.
MADE A FEW TWEAKS TO THE AFTERNOON TEMPERATURE CURVE AND SKY COVER
GRIDS...BUT OTHERWISE INHERITED FORECAST APPEARS ON TRACK FOR
ANOTHER FAIR AND UNSEASONABLY WARM JANUARY DAY.
TONIGHT/SUNDAY...STACKED RIDGING WILL KEEP THE WEATHER PATTERN
UNCHANGED THROUGH THE REMAINDER OF THE WEEKEND. OVERNIGHT LOWS WILL
MAINLY BE IN THE LOWER/MID 60S AT THE COAST AND MIDDLE 50S TO AROUND
60 INLAND BY SUNRISE. DAYTIME HIGHS CLIMB BACK INTO THE LOWER 80S
FOR MANY LOCATIONS SUNDAY AFTERNOON. LOCAL GRADIENT DOES SLACKEN A
BIT DURING THE DAY ON SUNDAY...AND DUE TO THE UNUSUALLY STRONG LAND
BASED HEATING...MAY SEE A FEEBLE SEA-BREEZE DEVELOP DURING THE
AFTERNOON...ESPECIALLY FROM PINELLAS COUNTY NORTHWARD. IF THIS WEAK
ONSHORE FLOW DOES DEVELOP THEN THE IMMEDIATE COAST WOULD END UP A
FEW DEGREES COOLER. REGARDLESS WILL BE FORECASTING ABOVE NORMAL
TEMPERATURES FOR ALL.
&&
.AVIATION...
EXPECT VFR CONDITIONS WITH OCNL BROKEN CIGS ABOVE 3000 FEET THROUGH
08Z. MVFR OR IFR VISIBILITIES IN FOG POSSIBLE AFTER 08Z SUNDAY.
&&
.MARINE...
SURFACE HIGH PRESSURE OFFSHORE OF THE SOUTHEAST U.S. WILL REMAIN IN
PLACE THROUGH EARLY NEXT WEEK WITH A SOUTHEAST WIND FLOW CONTINUING.
THIS HIGH WILL SHIFT SOUTH AND EAST OF THE REGION ON TUESDAY AS A
COLD FRONT MOVES INTO THE NORTHERN GULF WATERS. THIS FRONT WILL THEN
MOVE SOUTH THROUGH THE WATERS ON WEDNESDAY SHIFTING WINDS TO THE
NORTHWEST AND NORTH IN ITS WAKE.
&&
.CLIMATE...
HERE ARE SOME RECORD HIGH TEMPERATURES FOR TODAY.
TAMPA INTERNATIONAL 82 SET BACK IN 1989
SAINT PETERSBURG CLEARWATER 81 SET BACK IN 2005
SARASOTA/BRADENTON 86 SET BACK IN 1993
LAKELAND 85 SET BACK IN 1993
BROOKSVILLE 81 SET BACK IN 2008
FORT MYERS 85 SET BACK IN 1993
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 82 64 81 65 / 0 10 0 10
FMY 83 63 82 62 / 0 10 0 0
GIF 82 61 82 62 / 0 10 0 10
SRQ 80 62 80 61 / 0 10 0 10
BKV 83 55 82 55 / 0 10 0 10
SPG 79 65 79 65 / 0 10 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
528 AM EST SAT JAN 12 2013
.SHORT TERM... /TODAY THROUGH SUNDAY NIGHT/
HIGHLY COMPLEX MID/UPR TROPOSPHERIC WAVE INTERACTIONS/DEFORMATIONS
UNDERWAY ACRS UPR PLAINS BLIZZARD/SNOWSTORM IN PROGRESS. HIGHLY
BUCKLED FLOW PATTERN PER RIDGE AXIS ALONG WRN ATL AND 140W. THIS
ALONG WITH STRONGLY MERIDIONAL FLOW DOWNSTREAM OF INTMTN/CNTL
ROCKIES TROF WITH NMRS SHORTWAVES TRANSLATING THROUGH...FIRST
EJECTING FM NRN OLD MEXICO ATTM AND OTHER SIG WAVE ACRS WRN ALB TO
HELP REPLANT BASE ACRS THE SWRN STATES THROUGH THE SHORT TERM
PD...AFFORDING STRONG PERMANENCE IN THE SHORT TERM WITH A PRIMARILY
STRONG POS TILT TROF AXIS...PRESENTING AS A SLOW/STALLED EULARIAN
STREAM SYSTEM WITH EMBEDDED HIGH VELOCITY LAGRANGIAN SUBSCALE
FEATURES. GIVEN PRECONDITIONING WITH DEEP SRLY/SWRLY FLOW DOWNSTREAM
TO PROVIDE QUITE SECURE WARM/HIGH BULK MOISTURE AIRMASS /PWAT AOA
1.25-1.4 INCHES/ INTO SRN GRTLKS/OHIO VALLEY...WITH CONTINUAL LLVL
GOMEX SUSTENANCE FEED BENEATH SUBTROPICAL MOISTURE SWEEP IN THE
MID/UP LVLS.
SRN TAIL OF NRN PLAINS UPSTREAM SFC FNTL WAVE TO APPROACH LATE
TODAY...THOUGH IN A STRONGLY LYTIC FASHION ALONG ITS SRN EXTENSION
WITH BEST DEEPLY FORCED ASCENT HELD AT ABEYANCE WELL N/NW OF CWA.
SLIGHT DELAY IN ONSET OF PRECIP ASSOCD WITH TIMING OF SWRN TX FNTL
WAVE TONIGHT...CERTAINLY NOT WRT REVERSAL OF TROF TILT. SFC LOW ACRS
CNTL ARKANSAS AT F24...THEN QUICKLY INTO WRN LK ERIE BY 12 UTC SUN.
STRONG FGEN RESPONSE AMID WARM/MOIST AIRMASS TO RESULT IN LARGE RAIN
SWATH. SOME CONCERN WRT NEED OF FLOOD WATCH FOR MAUMEE AND WABASH
BASINS...HOWEVER ATTM SPEED OF SYSTEM ALONG WITH STRONG INDICATIONS
OF QUICK TAPER DURING THE DAY SUNDAY. FOR NOW WITH PRIOR RAFL/RUNOFF
RESPONSES BEING RELATIVELY MUTED...WILL SIMPLY ADDRESS IN ESF/HWO. A
SFC LOW TRACK POTNL THROUGH HEART AFOREMENTIONED BASINS GIVES
DISFAVOR FOR SECONDARY DEFORMATION ZONE ENHANCED PRECIP SWATCH.
AGAIN POSTFNTL UNDERCUT OF COLD AIR /DEPTH MAGNITUDE AND
POSITION/ OF DIRE IMPORTANCE WRT PTYPE. QUICK/ARDENT LOSS OF
MSTR/SATURATION DEPTH IN DRY SLOT PERHAPS SAVING GRACE AS ANTICIPATE
WINTRY MIX ACCUMS AOB HEADLINES AND/OR INCRSLY CONDITIONAL IN
NATURE. WL CERTAINLY ADDRESS POTNL/IN HWO.
MUTED LAKE RESPONSE WITH STRONGLY SHEARED IN CLOUD FLOW THAT
QUICKLY BACKS WRLY...SUPPORTING A SUBVERSIVE DRY UNDERCUT TO ANY
BANDS AS CANADIAN/PLAINS AIRMASS BEGINS TO QUICKLY BECOME ENTRAINED
THROUGH WI/SRN LK MI SUN EVE/NIGHT. DEPTH OF MSTR ALSO NEGATIVE
WITH DGZ FAILURE NOTED...PERHAPS EVEN AN ICE CRYSTAL NUCLAETION
FAILURE PSBLTY SUNDAY AFTN. ABOVE FACTORS OVERLAIN WITH OVERALL
LAME LAKE INDUCED THERMAL STABILITY...SUGGESTS LOW CHC SHSN AND/OR
SCT FLURRIES MENTION BEST ATTM.
&&
.LONG TERM...MONDAY THROUGH FRIDAY.
N/NW FLOW WILL HOLD THROUGH THE PERIOD WITH TEMPS NEAR OR BELOW
NORMAL. INITIALLY...DELTA T`S FAVORABLE FOR SOME LAKE EFFECT CLOUD
AND SNOW SHOWERS. HOWEVER...MSTR PROFILES QUITE ANEMIC AND WHAT DOES
EXIST IS MAINLY CONFINED NORTH OF THE FORECAST AREA. HAVE NUDGED
POPS UP TO 14 PERCENT ACROSS MI COUNTIES BUT NO INTRODUCTION OF ANY
WX MENTION AT THIS POINT.
A SERIES OF WEAK WAVES WILL MOVE THROUGH THE FLOW...IMPACTING MAINLY
THE NORTHERN PLAINS/GREAT LAKES AREAS. EACH WAVE WILL ATTEMPT TO
REINFORCE THE COLD AIR ACROSS THE REGION. MODELS VARY ON HOW FAR
SOUTH EACH OF THESE INTRUSIONS WILL BE. AT THIS POINT...FEW CHANGES
TO PAST GRIDS. ALLBLEND CONTINUES TO PLACE IN SLGT CHC POPS WITH
EACH WAVE...BUT WITH LESS THAN FAVORABLE TRACK FOR THE AREA SEE NO
REASON TO MESS UP GRIDS WITH SEVERAL PERIODS OF SLGT CHCS. TEMPS
WILL ATTEMPT TO MODERATE SOMEWHAT AT LEAST BACK TOWARDS NORMAL
THROUGH THE PERIOD.
POINT OF INTEREST...POLAR VORTEX WILL BEGIN ITS SLOW MIGRATION SOUTH
INTO HUDSON BAY THROUGH THE UPCOMING WEEK. WHILE MODELS HAVE BEEN
ADVERTISING ON AND OFF FOR SEVERAL WEEKS OF A ARCTIC INTRUSION
DROPPING INTO THE LAKES THIS HAS LARGELY NOT COME TO FRUITION AS OF
YET. 00Z RUNS OF EURO AND GFS BOTH IN GENERAL AGREEMENT ON LARGE
PIECE OF THIS VORTEX DROPPING SOUTH ENOUGH TO IMPACT THE AREA WITH
-28 C OR COLDER TEMPS DROPPING THROUGH THE WESTERN GREAT LAKES
TOWARDS THE FORECAST AREA. AS ALWAYS...CONFIDENCE IN ANY MODEL 240
HOURS OUT VERY VERY LOW...SOMETHING TO MONITOR TREND WISE OVER THE
NEXT WEEK.
&&
.AVIATION... /06 UTC TAFS/
PRIME FOCUS ON CURRENT/NEXT HAZARDS...LLWS/RAIN RESPECTIVELY. SLIGHT
ADJUSTMENTS TO SLIGHTLY MORE VEERED LLJ PER PRESENT UPSTREAM
VWP/PROFILER DATA AND RAP ANALYSIS. FOCUS FOR RENEWED LIFT IN
WARM/ABNORMALLY MOIST ENVIRONMENT COMMENCES LATE TONIGHT AND HAVE
INTRODUCED DOWNWARD TREND. SUSPECT HIR PROB FOR MORE WIDESPREAD IFR
MET CONDS TO BE REALIZED WITH TIME/BY 12 UTC SUN ACRS NRN IN...AND
TO BE ASSESSED IN LATER FCSTS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST MONDAY FOR LMZ043-046.
&&
$$
SHORT TERM...MURPHY
LONG TERM...FISHER
AVIATION...MURPHY
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
100 AM EST SAT JAN 12 2013
.AVIATION... /06 UTC TAFS/
PRIME FOCUS ON CURRENT/NEXT HAZARDS...LLWS/RAIN RESPECTIVELY. SLIGHT
ADJUSTMENTS TO SLIGHTLY MORE VEERED LLJ PER PRESENT UPSTREAM
VWP/PROFILER DATA AND RAP ANALYSIS. FOCUS FOR RENEWED LIFT IN
WARM/ABNORMALLY MOIST ENVIRONMENT COMMENCES LATE TONIGHT AND HAVE
INTRODUCED DOWNWARD TREND. SUSPECT HIR PROB FOR MORE WIDESPREAD IFR
MET CONDS TO BE REALIZED WITH TIME/BY 12 UTC SUN ACRS NRN IN...AND
TO BE ASSESSED IN LATER FCSTS.
&&
.UPDATE...
LINGERING STRATOCU HAS LIFTED NORTHWARD ACROSS SOUTHERN LOWER
MICHIGAN THIS EVENING WITH MAINLY HIGH LEVEL CLOUDINESS PERSISTING
ACROSS THE AREA. THE COMBINATION OF CONTINUED HIGH LEVEL CLOUDS
OVERNIGHT AND MODERATE GRADIENT PERSISTING SHOULD ALLOW FOR
MINIMAL TEMP DROPS FOR THE REMAINDER OF THE NIGHT. DESPITE
GRADIENT...SURFACE OBSERVATIONS ACROSS THE REGION INDICATING SOME
FAIRLY GOOD DECOUPLING EARLIER THIS EVENING WHICH HAVE ALLOWED
TEMPS TO DROP INTO THE MID AND UPPER 40S ACROSS NORTHERN PORTIONS
OF THE AREA. A FEW MORE DEGREES OF TEMPERATURE DROP ARE POSSIBLE
THIS EVENING...BEFORE A MORE STEADY TEMPERATURE TREND BECOMES
ESTABLISHED OVERNIGHT AS LOW LEVEL JET STRENGTHENS PLACING LOCAL
AREA IN MORE ROBUST WARM SECTOR ONCE AGAIN. SOME MINOR TWEAKS MADE
TO HOURLY TEMPERATURE CURVE TO ACCOUNT FOR EARLIER EVENING
DECOUPLING...BUT PREVIOUS FORECAST APPEARS TO BE IN GOOD SHAPE.
&&
.PREV DISCUSSION... /ISSUED 335 PM EST FRI JAN 11 2013/
SHORT TERM.../TONIGHT THROUGH SATURDAY NIGHT/
BALMY MID JANUARY WX IS EXPECTED TO CONTINUE INTO TONIGHT AND
SATURDAY...WITH ANOTHER ROUND OF RAIN (MIXING WITH SLEET/FREEZING
RAIN WESTERN AREAS) SATURDAY NIGHT...
DEEP SOUTHWESTERLY FLOW IN ADVANCE OF A DEEP WESTERN CONUS FULL
LATITUDE UPPER TROUGH WILL KEEP TEMPS UNUSUALLY MILD TONIGHT INTO
TOMORROW AS WARM SECTOR HAS BUILT IN BEHIND LAST NIGHTS LEAD WAVE
AND WARM FRONT. LOWS TONIGHT WILL BE AN IMPRESSIVE ~30F ABOVE
NORMAL WITH HIGHS ~25F ABOVE NORMAL TOMORROW.
ATTENTION THEN TURNS TO QPF/PTYPE OF PCPN PROGGED TO IMPACT THE
ENTIRE AREA SATURDAY NIGHT. LEAD WAVE OF LOW PRESSURE TRACKING
NORTHEAST THROUGH THE UPPER MIDWEST AND INTO ONTARIO TONIGHT INTO
SATURDAY WILL FORCE A SFC FRONTAL BOUNDARY SOUTHEAST INTO
SOUTHEASTERN PORTIONS OF OUR FA BY SATURDAY
AFTERNOON/EVENING...STALLING OUT HERE UNDER SOUTHWEST FLOW ALOFT.
A FRONTAL WAVE WILL DEVELOP ALONG THIS STALLED FRONT AS SHEARED
SHORTWAVE ENERGY NOW JUST OFF THE SOUTHERN CALIFORNIA COAST ROUNDS
THE BASE OF THE DEEP WESTERN CONUS TROUGH AND PROPAGATES NORTHEAST
INTO THE MID MS VALLEY AND GREAT LAKES. MODERATE TO HEAVY RAIN
SHOULD BLOSSOM ALONG THE DEEPENING FRONTAL CIRCULATION WITH A
STRONG AGEOSTROPHIC RESPONSE ANTICIPATED UNDER THE RIGHT ENTRANCE
REGION OF A 160 KT UPPER JET. THIS COMBINED WITH AN OPEN GULF OF
MEXICO AND DECREASED STABILITY (MODELS DEPICTING -EPV AND THETA-E
FOLDING ON XSECTIONS JUST ABOVE THE FRONTAL INVERSION) HINTS AT A
CONVECTIVE ELEMENT WITH A NARROW AXIS OF 1-2 INCH RAINFALL TOTALS
POSSIBLE INTO NE INDIANA AND NW OHIO. THIS COULD LEAD TO SOME
MINOR HYDRO RELATED PROBLEMS...CHECK ESFIWX (HYDROLOGIC OUTLOOK)
FOR DETAILS.
PTYPE BECOMES A CONCERN ACROSS NW INDIANA AND SW LOWER MICHIGAN
SATURDAY NIGHT...MAINLY AFTER MIDNIGHT...AS COLD AIR UNDERCUTS THE
LINGERING MELTING LAYER AND DYNAMIC COOLING COMMENCES. LATEST SREF
PROBABILITIES, ALONG WITH GFS/ECMWF ITERATIONS, SUGGEST THAT BETTER
CHANCES FOR MEASURABLE SNOW/SLEET WILL BE JUST WEST OF OUR AREA. SFC
TEMPS MAY COOL TO NEAR FREEZING AFTER 08/09Z IN OUR NW WHICH COULD
ALLOW FOR A BRIEF PERIOD OF FREEZING RAIN. EXPECT ANY FZRA TO BE
TRANSIENT WITH QUICK CHANGEOVER TO LIGHT SNOW/SLEET/DRIZZLE
LIMITING/INHIBITING ICE ACCRETIONS. OTHERWISE...OPTED TO HOLD
WITH SNOW/SLEET ACCUMS OF A TRACE TO 0.5" IN OUR FAR NORTHWESTERN
ZONES...MAINLY RAIN ELSEWHERE THROUGH DAYBREAK SUNDAY.
LONG TERM.../SATURDAY THROUGH THURSDAY/
MAIN CONCERN FOR LONG TERM PERIOD IS PRECIP TYPE ON SUNDAY AS
STORM SYSTEM DEPARTS. NEXT WEEK WILL FEATURE COLDER AIR AND A FEW
ALBERTA CLIPPER SYSTEMS MOVING BY TO OUR NORTH.
A POTPOURRI OF PRECIPITATION TYPES POSSIBLE ACROSS THE AREA ON
SUNDAY DEPENDING ON WHICH MODEL IS FAVORED. ECMWF THERMAL PROFILE
INDICATES FREEZING RAIN POTENTIAL ON SUNDAY MORNING FROM HIGHWAY 15
WEST WHILE GFS WOULD INDICATE NO FREEZING RAIN POSSIBILITY AND A
TRANSITION FROM RAIN TO MOSTLY SNOW WITH SOME SLEET BY MID DAY. WITH
TRANSITION ZONE DIRECTLY OVER THE FORECAST AREA...AND MODEL
UNCERTAINTY...HAVE KEPT MOST ALL PRECIP TYPES IN THE FORECAST AND
WILL ATTEMPT TO NARROW THE POSSIBILITIES IN FUTURE FORECAST
ISSUANCES.
AFTER THIS SYSTEM MOVES AWAY...A COLDER AIRMASS WILL MOVE IN. IF WE
CLEAR OUT ON MONDAY NIGHT...TEMPERATURES COULD GET QUITE COLD WITH A
HIGH PRESSURE CENTER OVER EASTERN ILLINOIS KEEPING WINDS LIGHT TO
CALM. A FEW CLIPPER TYPE SYSTEMS WILL MOVE BY TO OUR NORTH NEXT
WEEK. CONTINUED NORTHERLY FLOW BEHIND THESE SYSTEMS WILL ALLOW
ARCTIC CANADIAN AIR TO INFILTRATE MOST OF THE MIDWEST/UPPER GREAT
LAKES BY THE END OF THE WEEK. LONG TERM PATTERN LOOKS TO REMAIN
COOLER THAN NORMAL AS EASTERN CANADA TROUGH KEEPS OUR AREA IN
NORTHERLY FLOW.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST SATURDAY FOR LMZ043-046.
&&
$$
SHORT TERM...STEINWEDEL
LONG TERM...BENTLEY
AVIATION...MURPHY
UPDATE...MARSILI
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
303 PM CST SAT JAN 12 2013
.SYNOPSIS...
COLD FRONT PUSHING INTO THE OHIO VALLEY THIS AFTERNOON...WITH COLD
AIR OOZING INTO THE UPPER MISSISSIPPI VALLEY BEHIND IT. LONG WAVE
TROUGH SPANNING THE ROCKIES...WITH ENERGY LIFTING OUT OVER THE
CENTRAL US IN FAST SOUTHWEST FLOW. LEAD SHORTWAVE GENERATING SOME
SNOW/SLEET OVER NORTHERN MO AND INTO SE IA AT THIS TIME. MAIN
PRECIP AREA ACROSS SOUTHERN MO AND SOUTHERN ILLINOIS IS ALSO
EXPANDING NORTHWARD AND IS NOW PUSHING INTO CENTRAL ILLINOIS AHEAD
OF THE MAIN SHORT WAVE...WHICH CAN BE SEEN ON SATELLITE LIFTING OUT
OF ARKANSAS.
&&
.SHORT TERM...TONIGHT AND SUNDAY...
MAIN FORECAST QUESTIONS THIS AFTERNOON CENTER AROUND DEVELOPING
PRECIPITATION EVENT FOR TONIGHT. THE INITIAL WAVE OF LIGHT SNOW/SLEET
NOW MOVING ACROSS EASTERN IA WILL HELP COOL AND SATURATE THE COLUMN
AHEAD OF TONIGHTS WAVE BUT WILL HAVE LITTLE OTHER IMPACT. FOR TONIGHT...OF
THE SHORT RANGE MODELS...THE RAP IS THE MOST AGGRESSIVE WITH
SNOWFALL AMOUNTS...SUGGESTING 4 TO 6 INCHES ALONG AND EAST OF THE
MISSISSIPPI RIVER. MEANWHILE...THE NAM...GFS...AND ECMWF ARE MORE
CONSERVATIVE WITH 2-3 INCHES AT MOST. THUS WILL FAVOR A BLEND OF
THE NAM AND ECMWF FOR THIS FORECAST...ESPECIALLY FOR MOISTURE PARAMETERS.
THERE IS CONSISTENCY IN THE FORECAST SOUNDINGS...SHOWING A LARGE
WEDGE OF WARM AIR ALOFT...ESPECIALLY EAST OF THE MISSISSIPPI
RIVER...THAT WILL HAVE TO COOL BEFORE PRECIP CHANGES TO SNOW.
CURRENT THINKING IS THAT NEAR THE RIVER THE PERIOD OF SLEET SHOULD
BE BRIEF...BUT WILL LAST LONGER AS YOU GO EAST. BUREAU/PUTNAM
COUNTIES COULD SEE A COUPLE OF HOURS OF SLEET BEFORE IT CHANGES TO
SNOW BY MIDNIGHT. IT IS ALSO NOT OUT OF THE QUESTION FOR A BRIEF
PERIOD OF FREEZING RAIN TO FALL AT ONSET IN THE BUREAU/PUTNAM
COUNTY AREA. HOWEVER...IF THIS WOULD OCCUR...THE EVAPORATIVE
COOLING WOULD QUICKLY CHANGE IT TO SLEET. AND WITH THE WARM
TEMPERATURES THESE LAST FEW DAYS...ONLY ELEVATED SURFACES SHOULD
BE AT RISK FOR FREEZING.
IN TERMS OF SNOW AMOUNTS...THE GARCIA METHOD WOULD SUGGEST 2-4 INCHES
IN THE HEAVIEST BAND FROM THE QUAD CITIES NORTHEASTWARD. THE MODEL TIME
SECTIONS DO SUPPORT THIS...SHOWING POTENTIAL FOR DENDRITIC GROWTH
IN THAT SAME AREA. WHILE DENDRITES WOULD INCREASE AMOUNTS...THE SHORT
DURATION OF THE EVENT AND ANY SLEET AT ONSET WILL LIMIT THE
ACCUMULATIONS.
THE BOTTOM LINE IS THAT I EXPECT A SHARP CUT-OFF IN SNOW ACCUMULATIONS
SOMEWHERE IN THE VICINITY OF THE 380 CORRIDOR...THE HEAVIEST SNOW
AMOUNTS IN THE 2-4 INCH RANGE FROM NEAR THE QUAD CITIES NORTHEASTWARD
TO FREEPORT...AND A LONGER PERIOD OF SLEET WITH LESSER SNOW
ACCUMULATIONS AS YOU MOVE TOWARD THE PRINCETON ILLINOIS AREA. THE
MAIN PRECIP EVENT WILL BEGIN AFTER 6 PM TONIGHT...CHANGING TO SNOW
AREA WIDE BY MIDNIGHT AND SHOULD HAVE EXITED ALL BUT THE EXTREME
EASTERN PORTIONS OF THE CWFA BY 6 AM.
DMD
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...
SUNDAY NIGHT AND MONDAY...LATEST 12Z RUN MODELS IN GOOD AGREEMENT OF
SUGGESTING SFC RIDGING SLIDING ACRS THE REGION FROM THE WEST SUNDAY
NIGHT...WHILE CONFLUENT FLOW REGION WEST OF L/W TROF TRYING TO
PHASE ACRS THE EASTERN ROCKIES. EXPECT CLEARING SKIES AS HIGH CLOUDS
NORTHWEST OF LLVL BAROCLINIC REGION PUSH EASTWARD...COMBINED WITH
DECREASING WINDS FOR A COLD NIGHT OVER FRESH SNOW COVER. SOME SINGLE
DIGITS POSSIBLE BY EARLY MON MORNING. MAINLY CLEAR SKIES AND COLD
CONDITIONS TO FINISH OUT THE PERIOD WITH HIGHS IN THE 20S MON AND
SINGLE DIGITS TO LOWER TEENS MON NIGHT. SOME LIGHT RETURN FLOW MAY
MAKE FOR NON-DIURNAL TEMP TRENDS PRE-DAWN EARLY TUE MORNING WEST OF
THE MS RVR.
TUESDAY AND WEDNESDAY...LATEST RUN MEDIUM RANGE SOLUTIONS SUGGEST
THE ABOVE MENTIONED LONG WAVE TROF AXIS WILL SHEAR ACRS THE MID
CONUS THIS PERIOD FROM THE GRT LKS...ALL THE WAY TO THE BAJA OF MEX.
UPPER RIDGE ALONG AND JUST OFF THE WEST COAST AMPLIFIES...EVENTUALLY
DUMPING RIDGE-RIDING WAVE ENERGY DOWN ACRS THE UPPER MIDWEST AND GRT
LKS THROUGH MID WEEK. HOW FAR SOUTH THIS CLIPPER TYPE WAVE WILL
EVENTUALLY DIG IS STILL SOMEWHAT UNCERTAIN...ALL LONGER RANGE MODEL
SOLUTIONS BUT THE 12Z GFS KEEP LEAD WAVE AND IT/S ASSOCIATED PRECIP
TO THE NORTH OF THE AREA UNTIL MAYBE WED NIGHT WHEN SOME FLURRIES
MAKE IT ACRS THE NORTHEASTERN THIRD OF THE AREA/CWA UNDER RE-
ENFORCING CYCLONIC FLOW DIGGING ACRS THE SOUTHWESTERN GRT LKS. THE
12Z GFS IS MORE PROGRESSIVE AND DEEPER SOUTH WITH THE CLIPPER AND
PRODUCES LIGHT SNOW ACRS MOST OF THE LOCAL AREA TUE NIGHT INTO WED
MORNING BEFORE SHUTTLING QUICKLY OFF TO THE EAST. FOR NOW WILL SIDE
WITH THE MAJORITY AND KEEP THE FCST DRY...WITH THERMAL MODERATION
FROM THE SOUTHWEST AHEAD OF THE NORTHERN STREAM CLIPPER. HIGHS TUE
NEAR 30...MAY TRANSLATE INTO THE 30S BY WED BEFORE COLD FRONT OFF
THE PASSING CLIPPER SYSTEM TO THE NORTH SWEEPS THROUGH THE CWA BY
LATE WED.
THURSDAY THROUGH SATURDAY...LATEST RUN MEDIUM RANGE MODEL SOLUTIONS
AND ENSEMBLES GENERALLY SUGGEST WHILE A TYPE OF REX BLOCK SETS UP
ACRS THE WEST COAST AND SOUTHWESTERN U.S...BROAD UPPER LEVEL
TROFFINESS SETS UP ACRS MUCH OF THE EASTERN CONUS SOUTH OF NORTHERN
HUDSON BAY POLAR VORTEX. A RIBBON OF LLVL BAROCLINICITY SETS UP
PARALLEL TO THIS FEATURE FROM SOUTH CENTRAL CANADA...TO THE MID
ATLANTIC WHILE A BUILDING DOME OF VERY COLD AIRMASS LOOMS ACRS THE
EASTERN TWO THIRDS OF CANADA. WHILE THE REAL COLD AIR REMAINS BOTTLED
UP BY THIS PATTERN...WILL CONTINUE TO ADVERTISE MODERATING TEMPS
THROUGH SAT. DRY CONDITIONS TOO AS ANY IMPULSES WILL LOOK TO RIPPLE
ALONG THE BAROCLINIC RIBBON AND PRODUCE PRECIP MAINLY OT THE NORTH
ACRS THE DAKOTAS...MN...WI AND THE NORTH HALF OF THE GRT LKS INTO
SAT NIGHT. SOME LONGER RANGE SIGNS OF PLUNGING JET ENERGY TO ALLOW
SOME OF THE ARCTIC AIR TO BREAK LOOSE AND SPILL ACRS THE WESTERN
GRT LKS BY EARLY NEXT WEEK. ..12..
&&
.AVIATION...
A WINTRY MIX WILL OVERSPREAD THE AREA THIS EVENING. SITES ALONG
AND WEST OF THE MISSISSIPPI RIVER COULD SEE A BRIEF PERIOD OF
SLEET AT ONSET WHICH WILL RAPIDLY CHANGE OVER TO SNOW. EAST OF THE
MISSISSIPPI RIVER...ROUGHLY FROM PRINCETON IL TO MACOMB
IL...PRECIPITATION IS EXPECTED TO BEGIN WITH A BRIEF PERIOD OF
FREEZING RAIN EARLY THIS EVENING...CHANGING TO SLEET FOR SEVERAL
HOURS...AND THEN FINALLY OVER TO SNOW AROUND MIDNIGHT. AREA
WIDE... SNOWFALL RATES WILL BE MOST INTENSE BETWEEN 3Z AND 9Z
OVERNIGHT... AND SNOW IS EXPECTED TO END BY 12Z. OTHERWISE... BY
02Z LOOK FOR PREDOMINANTLY MVFR CIGS AND VSBYS WITH LOCAL IFR IN
HEAVIER PRECIPITATION.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
SUNDAY FOR CLINTON-DES MOINES-JACKSON-LEE-LOUISA-MUSCATINE-
SCOTT.
IL...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
SUNDAY FOR BUREAU-CARROLL-HANCOCK-HENDERSON-HENRY IL-JO
DAVIESS-MCDONOUGH-MERCER-PUTNAM-ROCK ISLAND-STEPHENSON-
WARREN-WHITESIDE.
MO...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
SUNDAY FOR CLARK.
&&
$$
DMD/12/DMD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1132 PM CST FRI JAN 11 2013
.AVIATION...
VFR CONDITIONS WILL PREVAIL MOST TO ALL OF THE NEXT 24 HOURS AT ALL
TERMINALS. KCID AND KDBQ TERMINALS...A 1 TO 3 HOUR PERIOD OF SCT-
BKN LOW CLOUDS AT 1-2K AGL MAY FOLLOW COLD FRONTAL PASSAGE BETWEEN
12-15Z THIS MORNING. AFTER 21Z...BKN-OVC LOW/MID CLOUDS WITH
POSSIBLY LIGHT SNOW MAY AFFECT KMLI AND KBRL TERMINALS WITH MVFR
CONDITIONS POSSIBLE IN ANY SNOW THROUGH 13/06Z.
NICHOLS
&&
.PREV DISCUSSION... /ISSUED 302 PM CST FRI JAN 11 2013/
SYNOPSIS...
12Z UA ANALYSIS HAS A STRONG SYSTEM OVER THE ROCKIES WITH STRONG
SOUTHWEST FLOW FROM NORTHERN MEXICO INTO THE GREAT LAKES.
SATELLITE TRENDS THROUGH MID AFTERNOON INDICATE THE LOW CLOUDS ARE
BREAKING UP AS DEEPER MIXING OCCURS BUT MID AND HIGH LEVEL CLOUDS
ARE STREAMING IN OVER THE REMAINING LOW CLOUDS.
18Z SFC ANALYSIS HAS A LOW NORTH OF KATY WITH ANOTHER NORTHEAST OF
KLIC. A STRONG COLD FRONT CONNECTED BOTH LOWS AND THERE WERE
NUMEROUS TROFS FROM THE GREAT LAKES BACK INTO THE SOUTHERN PLAINS.
DEW POINTS WERE IN THE TEENS AND 20S ACROSS THE NORTHERN PLAINS
WITH 30S AND 40S ACROSS MUCH OF THE GREAT LAKES AND MIDWEST. DEW
POINTS IN THE 50S AND 60S RAN FROM THE OHIO VALLEY INTO THE DEEP
SOUTH.
SHORT TERM...LATE THIS AFTERNOON THROUGH SATURDAY
WE ARE DEALING WITH ADVECTION FOG. IN ADVECTION FOG YOU CAN HAVE
EXTREMELY DENSE FOG EVEN THOUGH WINDS ARE 10 TO 20 MPH. ALBEIT FAR
FROM PERFECT...THE RAP MODEL TRENDS STRONGLY POINT TO DENSE FOG
CONTINUING INTO THE EVENING ACROSS THE NORTHERN CWFA.
AS FOR HEADLINES...THE DENSE FOG ADVISORY WILL BE EXTENDED UNTIL
MIDNIGHT FROM DUBUQUE ON WEST IN THE HWY 20 CORRIDOR. PER
OBSERVATIONS AND WHAT WEB CAMS ARE AVAILABLE...THE NORTHERN PARTS
OF LINN/JONES/JACKSON COUNTIES IN IOWA AND STEPHENSON COUNTY IN
ILLINOIS STILL HAVE DENSE FOG OVER THEM. THUS THESE COUNTIES AND
JO DAVIESS COUNTY WILL HAVE THE DENSE FOG ADVISORY EXTENDED
THROUGH 6 PM.
THE POSSIBILITY DOES EXIST THAT THE HEADLINES MAY BE DROPPED
EARLY. THAT WILL DEPEND UPON STRONGER WINDS PROMOTING MIXING OF
THE BOUNDARY LAYER TO CAUSE THE FOG TO LIFT.
AFTER MIDNIGHT...A STRONG COLD FRONT WILL SWEEP THROUGH THE CWFA.
THIS FRONT WILL SCOUR OUT WHAT REMAINING FOG IS ACROSS THE AREA.
VERY BRISK CONDITIONS WILL BE SEEN ACROSS THE AREA ON SATURDAY
BEHIND THE FRONT.
THE STRENGTH OF THE CAA ON SATURDAY WOULD NORMALLY RESULT IN
UNSTABLE CONDITIONS WITH CONVECTIVE SHOWERS DEVELOPING. HOWEVER...
LOW LEVEL LAPSE RATES REMAIN QUITE STABLE DURING THE DAY AND FCST
SOUNDINGS SHOW A VERY PRONOUNCED INVERSION ACROSS THE AREA. THUS
SATURDAY WILL REMAIN DRY.
LOW TEMPERATURES TONIGHT WILL OCCUR AROUND 8 AM SATURDAY. THE HIGH
TEMPERATURES FOR THE DAYLIGHT HOURS ON SATURDAY WILL OCCUR BETWEEN
8 AND 10 AM FOLLOWED BY SLOWLY FALLING TEMPERATURES. TEMPERATURES
MAY REBOUND A LITTLE DURING THE AFTERNOON BUT WILL BE BELOW THE
MORNING HIGHS. ..08..
LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
SATURDAY NIGHT AND SUNDAY TO BE THE TRICKY PERIOD. LAST NIGHT THE
ECMWF TOOK A JOG TO THE NORTHWEST WITH A SHORTWAVE AND SURFACE
LOW THAT MOVES FROM EAST TEXAS NORTHEAST UP THE OHIO VALLEY. IT
APPEARS TO BE BRINGING THE WHOLE FEATURE FARTHER NORTHWEST...AS
WELL AS TAKING ADVANTAGE OF SOME DEEPER FRONTOGENESIS THAT SEEMS
TO BE FORMING ON THE NORTH SIDE OF THE FEATURE. THIS
MORNING...MORE OF THE MODELS FOLLOWED THAT TREND...AND ARE NOW
BRINGING A NICE SWATH OF SNOW TO THE FORECAST AREA. AREAS
SOUTHEAST OF A LINE FROM CEDAR RAPIDS TO DUBUQUE ARE NOW LOOKING
AT A NICE 1 TO POSSIBLY 3 INCH SNOWFALL EVENT...ASSUMING WE CAN
GET ENOUGH MOISTURE INTO THE AREA AND THE ECMWF AND GFS
ISENTROPIC AND FRONTOGENESIS LIFT PROGS ARE CORRECT. HAVE RAISED
POPS...BUT IF THIS TREND CONTINUES WITH TONIGHTS MODEL RUNS...WE
COULD RAISE POPS AGAIN.
SUNDAY NIGHT AND MONDAY TO BE COLD...ESPECIALLY IF WE CAN GET
SOME SNOW ON THE GROUND TO ENHANCE THE STRONG SURFACE RIDGE THAT
WILL BE SITTING OVER THE AREA BY EARLY MONDAY MORNING. AT THIS
TIME IT LOOKS LIKE WE MAY SEE SOME SINGLE DIGITS IN THE NORTHWEST
PORTIONS OF THE FORECAST AREA. IF WE DO GET THE NEW
SNOWPACK...NEARLY THE WHOLE CWA COULD HAVE SINGLE DIGIT MINS WITH
NEAR ZERO VALUES POSSIBLE NORTHWEST. HIGHS ON MONDAY TO STILL BE
CHILLY WITH THE RIDGE STILL OVERHEAD...AND CURRENTLY HAVE MID TO
UPPER 20S.
TUESDAY THE MAIN UPPER LEVEL TROUGH TO SLOWLY MOVE
OVERHEAD...INCREASING CLOUD COVER SOMEWHAT AND WITH SOME WEAK
WARM AIR ADVECTION BEGINNING ALOFT SOME MODERATION OF TEMPERATURES
IS POSSIBLE.
WEDNESDAY A STRONG CLIPPER IS LIKELY TO MOVE OUT OF CANADA IN THE
LONGWAVE TROUGH. THIS SYSTEM TO STAY MOSTLY NORTH OF THE
AREA...BUT IT WILL PULL SOME WARMER TEMPERATURES ALOFT OVER THE
AREA...FOR A CONTINUATION OF THE WARMING TREND STARTED ON TUESDAY.
HIGHS WEDNESDAY AFTERNOON SHOULD BE IN THE 30S NEARLY EVERYWHERE.
WITH THE CLIPPER NOW HAVING MOVED OFF TO THE EAST BY WEDNESDAY
NIGHT...A FRESH SHOT OF COLDER AIR WILL MOVE INTO THE CWA FROM
THE NORTH AS THE UPPER LEVEL TROUGH AXIS SHARPENS. IT LOOKS LIKE A
SHORTWAVE MAY DIVE THROUGH THE AREA THURSDAY...BUT SOME MODELS
KEEP IT TOO FAR NORTH TO AFFECT THE AREA...SO HAVE LEFT FORECAST
DRY FOR NOW. FRIDAY LOOKS COLD AND DRY AS WELL.
LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
NICHOLS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
245 PM EST SAT JAN 12 2013
.SYNOPSIS...
CROSSING LOW PRESSURE WILL SPREAD RAIN OVER THE UPPER OHIO VALLEY
REGION ON SUNDAY...AND WILL PULL A COLD FRONT THROUGH BY MONDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
SHRA AREA WITH SHRTWV IN SWLY FLOW ALOFT WAS MOVG ACRS KY THIS
AFTN...AND THAT CLUSTER IS EXPECTED TO DVLP UP THE OH RIVER AND
SHOULD AFFECT THE AREA LTR THIS EVE. EVE PRECIP PROBABILITIES HAVE
BEEN ADJUSTED FOR THIS POTENTIAL USING RAP HRLY OUTPUT...AND
BASICALLY FOCUS THE BTR SHRA CHCS OVR AREAS WEST OF PITTSBURGH
BEFORE THE DISTURBANCE LIFTS NWD LTR TNGT.
OTHERWISE...VERY WARM TEMPERATURES CAN BE EXPECTED THROUGH SUNDAY
AS DETERMINISTIC MODELS HAVE CONTINUED THE TREND OF HOLDING FRONT
TO THE WEST OF THE REGION THROUGH THE NEAR TERM. IN ADDITION...THE
HEAVIER RAIN POTENTIAL WILL ALSO BE SHIFTED WEST WITH THE
BOUNDARY...THUS LIMITING RAIN AMOUNTS FOR MOST COUNTIES AS WELL AS
ALLOWING MORE RUNOFF TIME FOR THE LAST OF THE SNOW MELT.
THE FORECAST THUS FEATURES REDUCED PRECIP PROBABILITIES FOR LATE
TNGT AND EARLY SUNDAY...ALTHOUGH CHC NMBRS HAVE GENLY BEEN MAINTAINED
UNTIL LOW PRES SWEEPS ACRS OHIO DURING THE AFTN. CATEGORICAL NMBRS
HAVE BEEN RECONSTRUCTED FOR THAT EVENTUALITY WITH RAIN AMOUNTS
APPROACHING AN INCH LIMITED TO AREAS ALONG AND NORTH OF A ZANESVILLE
TO FRANKLIN LINE.
GIVEN THIS SCENARIO...STREAM AND RIVER RISES CAN BE EXPECTED...BUT
FLOODING IS NOT ANTICIPATED.
THE WARM NEAR TERM TEMPS WERE FORECAST USING LAMP GUIDANCE AND
PERSISTENCE FOR SUNDAY.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
A TAPERING OF POPS TO LIKELY NMBRS WAS COMPLETED FOR SUNDAY
EVE...AND TO CHC NMBRS THEREAFTER AS THE AFOREMENTIONED LOW DRAGS
THE COLD FRONT OVR THE UPR OH REGION WITH ITS EXIT. RESIDUAL RAIN
SHOWERS MAY CHANGE TO SNOW BY MONDAY MRNG...BUT NO SIGNIFICANT
ACCUMULATION IS FORTHCOMING.
THE LATEST NAM AND GFS ARE IN AGREEMENT IN DEPICTIONS OF
SUFFICIENT SWD PENETRATION OF THE FRONT FOR DRY WEATHER FOR MOST
ZONES...AND A STEADY POP REDUCTION FOR SERN COUNTIES ON MONDAY.
THOSE MDLS ALSO INDICATE DVLPMNT OF LOW PRES ALNG THE FRONT ON
TUESDAY. THAT SYSTEMS PROGRESS ACRS THE VIRGINIAS MAY SPREAD PCPN
OVR AREAS ARND AND SE OF MORGANTOWN...AND WARM ADVCTN ABOVE THE
BNDRY LYR MAY BE SUFFICIENT FOR A PERIOD OF FREEZING RAIN WITH THE
LIGHT SNOW FOR THE RIDGE ZONES.
FOR NOW...LOW CHC POPS WL SUFFICE FOR THAT SITUATION AS THE BETTER
POTENTIAL LKS TO BE FARTHER SOUTH AND EAST.
SHORT TEMPS WERE FORECAST USING A BLEND OF GUIDANCE AND GENERALLY
FEATURE A SLOWER COOLING TREND.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
SVRL WEAK AND FAST MOVG SYSTEMS ARE EXPD THRU THE PD. WITH TIMING
DETAILS DIFFERING AMONG THE MODELS...PREFERRED AN ECMWF/HPC CHART
BLEND TO SMOOTH OUT SOME OF THE DIFFERENCES.
EXPCTG HIGH PRES TO BLD IN TUE NGT INTO WED. A COLD FRONT IS EXPD TO
DROP SE ACRS THE GT LKS RGN WED NGT INTO THU WITH A CHC OF SHSN...BUT
MOISTURE IS LMTD. A FEW SHSN MAY LINGER IN COLD WRLY FLOW THRU THU
NGT BEFORE ANOTHER WK SYSTEM SKIRTS THE NRN PTN OF THE CWA FRI. YET
ANOTHER WK COLD FRONT IS EXPD FOR SAT. MAY SEE JUST ENOUGH WARM AIR
AHEAD OF IT FOR A MIX OF SHRA/SHSN...BUT AGAIN MOISTURE SHOULD BE
LMTD. WENT NR OR A LTL BLW HPC TEMP GUIDANCE...RESULTING IN NR OR
SLIGHTLY ABV NRML TEMPS THRU THE PD.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
LOW LVL MOISTURE WL CONT TO BRING OCNL MVFR CIGS TO MOST OF THE TAF
SITES THROUGH THIS AFTN...EXCPT IFR FOR FKL AND DUJ. THINK THE LWR
CIGS WL SCT OUT BY THIS EVE...THEN IFR REDVLPS FOR FKL AND DUJ OVRNGT.
WITH MID LVL CLDS NOT CERTAIN REST OF THE TAF SITES WL SEE SGFNT
RESTRICTIONS...BUT WL HAVE TO MONITOR FOR THIS THRU THE EVE. LLVL JET
MOVG IN OVRNGT WL BRING A LLWS POTENTIAL AFTR 08-10Z MOST PLACES.
SHOULD GET SOME LMTD MIXING AFT 15Z SUN SO ENDED LLWS EXCPT FOR
FKL/DUJ WHERE LOW CLDS SHOULD LIMIT MXG. A COLD FRONT WL APRCH FM
THE WEST SUN...AND MENTIONED SHRA AT ZZV BY LT MRNG...AND LT AFTN
FOR PIT.
.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
RESTRICTIONS ARE EXPD SUN NGT INTO MON AS THE COLD FRONT MOVES THRU
THE AREA. RESTRICTIONS ARE PSBL AGAIN WED NGT AND THU AS ANOTHER COLD
FRONT MOVES THRU.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
15/07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
722 PM EST SUN JAN 13 2013
.UPDATE...
ISSUED AT 721 PM EST SUN JAN 13 2013
CALLS TO SPOTTERS IN ALGER/LUCE COUNTY AND A LOOK AT RADAR IMAGERY
INDICATE ONLY -SHSN ARE ONGOING IN THAT AREA ATTM. DESPITE APRCH OF
DISTURBANCE/AREA OF DEEPER MSTR...LLVL ACYC FLOW/LACK OF LLVL CNVGC
APPEARS TO BE THE MAIN IMPEDIMENTS TO HEAVIER LES DEPSITE ONSHORE NW
FLOW AND SUFFICIENTLY LO H85 TEMPS...-13C TO -15C PER RUC ANALYSIS.
LATEST HI RES NUMERICAL MODELS INDICATE LLVL FLOW WL BECOME MORE CYC
WITH FOCUSED LLVL CNVGC IN ERN ALGER/NRN LUCE COUNTIES FOLLOWING
PASSAGE OF UPR DISTURBANCE OVERNGT AS EVEN COLDER AIR WITH H85 TEMPS
FALLING TO -18C BY 12Z. THESE FACTORS SHOULD CONSPIRE TO INCRS
INTENSITY OF THE SHSN IN THIS AREA AFT 06Z. SO ADJUSTED THE LES ADVY
TIMING TO 06Z TO 18Z FOR ALGER/LUCE COUNTIES. BY 18Z MON...EXPECT
THE LARGER SCALE FLOW TO BACK SUFFICIENTLY WSW TO END THE LES IN
ALGER/LUCE COUNTIES.
HEADLINES FOR ONTONAGON/HOUGHTON/KEWEENAW COUNTIES APPEAR ON TRACK
AND VERIFIED BY RECENT SN REPORTS. SO MADE NO CHANGES TO THE ADVYS
IN PLACE FOR THOSE ZONES.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 400 PM EST SUN JAN 13 2013
MOISTURE DECREASES AND THE INVERSION HEIGHT FALLS TO AROUND 900MB AT
IWD AROUND OR SHORTLY AFTER 06Z...DECREASING THE POTENTIAL FOR ANY
SIGNIFICANT ACCUMULATION BEYOND THAT POINT. MUCH OF BARAGA AND
MARQUETTE COUNTIES WILL ALSO MISS OUT ON ACCUMULATIONS GREATER THAN
AN IN INCH OR TWO NEAR THE SHORELINES. OTHERWISE AROUND THE S EDGE
OF LAKE SUPERIOR...FAVORABLE NW FLOW OFF THE RELATIVELY WARM
WATERS...PLENTY OF MOISTURE BELOW 850MB COINCIDING WITH THE
DGZ...WILL CONTINUE TO BRING BANDS OF LAKE EFFECT SNOW SHOWERS FROM
THE PORCUPINE MOUNTAINS...AND MAINLY EAST OF AU TRAIN THROUGH N LUCE
COUNTY.
WHILE ACCUMULATIONS WILL LIKELY BE LESS FOR THE 6HR PERIOD FORM
06Z-12Z FOR THE WESTERN ADVISORY...WITH ACCUMULATIONS OF 1-2IN...THE
INTENSITY WILL LIKELY PICK UP AGAIN TOWARD DAYBREAK AT WINDS TURN
MORE WESTERLY...BRINGING THE FOCUS UP TO THE TWIN
LAKES-PAINESDALE-CMX AREA...AND THEN LIKELY FROM FREDA-CMX AND N BY
LATE AFTERNOON. THE BEST SNOW MAY ALSO BE ONGOING TOWARD THE END OF
THE EASTERN ADVISORY /MONDAY MORNING/...GIVEN THE WIND DIRECTION AND
850MB TEMPS FALLING FROM AROUND -12C THIS AFTERNOON TO AROUND -16C.
VERY LITTLE CHANGE WILL BE NOTED OVER THE W...WITH ONLY ABOUT A 2C
DROP IN 850MB TEMPS.
WENT A LITTLE MORE OPTIMISTIC WITH THE CLEARING/DIMINISHING CLOUD
COVER TONIGHT AND MONDAY OVER CENTRAL UPPER MI...AS HIGH PRESSURE
ACROSS THE N AND CENTRAL PLAINS SLOWLY WEAKENS THE LINGERING TROUGH
OVERHEAD.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 PM EST SUN JAN 13 2013
LAKE EFFECT SNOW WILL DOMINATE THE FORECAST FOR MOST OF THE LONG
TERM. IN FACT...AREAS FAVORED IN WESTERLY AND NORTHWESTERLY FLOW
WILL LIKELY SEE SNOW EACH DAY IN SOME FORM OR ANOTHER THROUGH NEXT
WEEKEND. AWAY FROM THESE AREAS...IT WILL END UP BEING FAIRLY
DRY...ALTHOUGH THERE WILL BE SOME OPPORTUNITIES FOR SNOW WITH
CLIPPER SYSTEMS.
LAKE EFFECT SNOW WILL BE ONGOING MONDAY NIGHT IN THE WESTERLY PBL
FLOW. IN FACT...THE NAM AND LOCAL HIGH RES MODELS SUGGEST A SINGLE
DOMINATE BAND CONTINUING FROM MONDAY AFTERNOON AND PERHAPS
INTENSIFYING SOME AS A WEAK UPPER DISTRUBANCE MOVES OVERHEAD WITH A
LITTLE ADDITIONAL MOISTURE. STILL LOOKS LIKE A DOMINATE BAND OF SNOW
WILL PERSIST ACROSS THE KEWEENAW MONDAY NIGHT...THEN GRADUALLY SHIFT
NORTH ON TUESDAY AS WINDS BACK AHEAD OF THE NEXT CLIPPER SYSTEM.
TRICKY SNOWFALL FORECAST FOR THE KEWEENAW MONDAY NIGHT...AS THE EQL
HEIGHT WILL RAISE TO NEARLY 9000 FT AND NEARLY ALL OF THE BEST OMEGA
LIES IN THE DGZ. IN FACT...THE COBB METHOD WOULD SUGGEST SNOW RATIOS
OF 25-30:1 MONDAY NIGHT. THIS COMBINED WITH QPF VALUES OF AROUND
0.15 INCH MON NIGHT WOULD SUGGEST THAT LES ADVISORY FOR THE KEWEEWAW
WILL NEED TO BE EXTENDED THROUGH MON NIGHT. WILL NEED TO WATCH FOR
HIGHER AMOUNTS OF SNOW ON MONDAY NIGHT...BUT EXTENDING THE ADVISORY
SEEMS TO BE THE BEST COURSE OF ACTION FOR NOW.
TUESDAY WILL GENERALLY BE QUIET AHEAD OF A CLIPPER SYSTEM. WEAK WARM
ADVECTION SHOULD ALLOW TEMPS TO RISE INTO THE UPPER TEENS AND LOWER
20S. THE CLIPPER SYSTEM MOVES THROUGH TUESDAY NIGHT INTO WED
MORNING. BEST DYNAMICS ACROSS LAKE SUPERIOR AND HAVE SUCH HAVE
PLACED THE HIGHEST POPS ACROSS THE LAKE AND OVER THE EASTERN PART OF
THE FORECAST AREA WHERE THERE MAY BE SOME WEAK LAKE MICHIGAN
ENHANCEMENT. WILL KEEP CHANCE POPS ACROSS THE NORTH CENTRAL DUE TO
DOWNSLOPING S-SW WINDS. IN FACT...THESE WINDS WILL BE RATHER GUSTY
INTO WED MORNING. THE COLD FRONT/TROUGH ENDS UP SLOWING DOWN AS IT
CROSSES THE REGION WED. THIS WILL MAKE IT JUST MARGINALLY COLD FOR
LES IN THE NW FAVORED SNOWBELTS UNTIL LATER WED AFTN INTO WED NIGHT
WHEN THE COLD AIR SURGES SOUTHWARD ONCE AGAIN. 850MB TEMPS WED NIGHT
DROP TO -24C ACROSS THE LAKE SO THERE IS NO REASON WHY LES WILL NOT
CONTINUE.
ALTHOUGH THE MODELS DIFFER ON THE SPECIFICS IN DAYS 4-7
(THURSDAY-SUNDAY)...ALL SIGNS CONTINUE TO POINT TOWARD SOME OF THE
COLDEST AIR OF THE YEAR THUS FAR MOVING ACROSS THE GREAT LAKES AS
THE ARCTIC VORTEX MOVES TO SOUTHERN HUDSON BAY BY THE END OF THE
WEEK. WITH THE AREA BEING UNDER NW FLOW...CLIPPER SYSTEMS ALONG WITH
LES WILL BE THE MAIN DRIVERS FOR PRECIPITATION. AS USUAL...THE
TIMING OF THESE SYSTEMS WILL BE DIFFICULT...BUT THE EMPHASIS IN THE
EXTENDED WILL BE MUCH COLDER WITH CHANCES FOR SNOW EACH DAY.
AS FOR A LITTLE MORE SPECIFICS...THURSDAY LOOKS TO BE COLD DAY WITH
850MB TEMPS DROPPING TO AROUND -25C BEHIND THE CLIPPER SYSTEM. THE
GFS AND ECMWF BOTH IMPLY AN INVERTED TROUGH HANGING OVER THE LAKE
ESPECIALLY ACROSS THE EAST AS THE SURFACE RIDGE MAINLY SLIDES SW OF
THE FORECAST AREA. THIS WILL LIKELY ALLOW FOR LAKE EFFECT SNOW TO
PERSIST IN THE W-NW FLOW FAVORED SNOW BELTS SUCH AS THE AREA FROM
ONTONAGON TO THE KEWEENAW...AS WELL AS PLACES WELL EAST OF MUNISING.
ALTHOUGH THERE WILL BE EXTREME INSTABILITY OFF THE LAKE WITH LAKE
INDUCED DELTA-T VALUES OF 25-30C...EXPERIENCE SUGGESTS THAT SNOW
RATIOS TEND TO BE QUITE LOW (GENERALLY 15-20:1) WITH ARCTIC TYPE LES
DUE TO THE BEST DGZ BEING NEAR THE GROUND. DUE TO THIS AND THE
DECREASING INVERSION AND BACKING WINDS INTO FRIDAY...IT IS UNCLEAR
HOW HEAVY THE SNOW WILL ACTUALLY FALL...ALTHOUGH SNOW WILL BE RATHER
PERSISTENT. FOR NOW...WILL CONTINUE WITH LIKELY POPS IN THE NW
FAVORED SNOW BELTS SIMILAR TO PREVIOUS FORECASTS.
DIFFERENCES OCCUR BETWEEN THE GFS AND ECMWF FOR THE WEEKEND. THE
ECMWF IS MUCH MORE AGRESSIVE WITH THE WEEKEND SYSTEM...WITH THIS
SYSTEM OPENING THE DOOR FOR THE ARCTIC VORTEX PLUNGING ACROSS THE
UPPER GREAT LAKES BY SUNDAY NIGHT. THE GFS IS SLOWER...WAITING UNTIL
SUN NIGHT CLIPPER FOR THE ARCTIC VORTEX TO SHIFT SOUTH. REGARDLESS
OF WHAT HAPPENS...ALL SIGNS ARE POINTING TOWARD A VERY COLD PERIOD
STARTING EITHER NEXT SUNDAY OR NEXT MONDAY. THE ECMWF CONTINUES TO
SHOW 850MB TEMPS OVER LAKE SUPERIOR OF -35C BY NEXT MONDAY AND
ALTHOUGH THE GFS IS WARMER...THE BROAD LONG WAVE PATTERN IS SIMILAR.
WILL NOT GET TOO SPECIFIC FOR THE WEEKEND AND HOLD ONTO A CHANCE OF
SNOW EACH DAY. THERE WILL LIKELY BE A PERIOD OF MORE WIDESPREAD SNOW
AS THE CLIPPER MOVES THROUGH...BUT THAT IS BEYOND THE PREDICTABILITY
OF THE NWP RIGHT NOW.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 624 PM EST SUN JAN 13 2013
CMX...EXPECT PREDOMINANT IFR CONDITIONS THIS PERIOD WITH PERSISTENT/
UPSLOPE WNW FLOW AND SUFFICIENT INSTABILITY FOR LES. THE BEST CHC
FOR LIFR WX WL BE THIS EVNG AS DISTURBANCE/AREA OF DEEPER MSTR
IMPACT THE AREA AND AGAIN ON MON MRNG WITH RETURN OF AREA OF SHARPER
LLVL CNVGC ASSOCIATED WITH SLOWLY BACKING LARGER SCALE FLOW.
IWD...WITH ARRIVAL OF DISTURBANCE/DEEPER MSTR THIS EVNG...EXPECT VFR
WX EARLY TO DETERIORATE TO MVFR/OCNL IFR CONDITIONS. ONCE THIS
DISTURBANCE PASSES AND THE FLOW BACKS MORE TO THE WSW LATER TNGT...
THE MORE SGNFT SHSN WL DIMINISH. VFR CONDITIONS WL RETURN ON MON AS
THE BACKING LLVL FLOW ADVECTS DRIER AIR OVHD.
SAW...ALTHOUGH MVFR CONDITIONS MAY OCCUR THIS EVNG ASSOCIATED WITH
THE PASSAGE OF AN UPR DISTURBANCE/DEEPER MSTR...EXPECT PREDOMINANT
VFR WX THIS FCST PERIOD WITH DOWNSLOPE WNW FLOW VEERING WSW
ADVECTING DRIER AIR INTO THE AREA IN THE WAKE OF DEPARTING
DISTURBANCE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 PM EST SUN JAN 13 2013
THE TROUGH LINGERING ACROSS LS WILL SLOWLY WEAKEN AS HIGH PRESSURE
SINKS FROM CENTRAL CANADA INTO THE MID MISSISSIPPI VALLEY. EXPECT
THE HIGH TO SLOWLY EXIT S TUESDAY IN RESPONSE TO A STRONGER LOW OVER
SASKATCHEWAN SWINGING ACROSS ONTARIO TUESDAY NIGHT...AND INTO QUEBEC
ON WEDNESDAY. SW GALES TO 35KTS WILL BE POSSIBLE TUESDAY AFTERNOON
THROUGH TUESDAY NIGHT. EXPECT THE EXTENDING TROUGH TO PUSH ACROSS LS
ON WEDNESDAY...WITH A NW GALES TO 35KTS POSSIBLE BEHIND THE
TROUGH...MAINLY WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT. A GALE
WATCHED HAS BEEN POSTED FOR PORTIONS OF LAKE SUPERIOR. WINDS WILL
SLOWLY DIMINISH AS THE TROUGH WEAKENS THURSDAY THROUGH FRIDAY IN
RESPONSE TO LARGE HIGH PRESSURE ONCE AGAIN NEARING FROM CENTRAL
CANADA AND THE PLAINS STATES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001-003.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST MONDAY FOR MIZ002.
LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 1 PM EST MONDAY FOR
MIZ006-007.
LAKE SUPERIOR...
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING FOR
LSZ265>267.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY AFTERNOON
FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...KF
LONG TERM...MRD
AVIATION...KC
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1246 PM EST SAT JAN 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 534 AM EST SAT JAN 12 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NW ONTARIO INTO THE SW CONUS AND A RIDGE OVER THE EAST RESULTING IN
SW FLOW FROM THE SRN PLAINS INTO THE WRN GREAT LAKES. A SHEARED
SHORTWAVE TROUGH WAS LIFTING NORTHEAST THROUGH NRN MN. AT THE
SFC...A 993 MB LOW WAS LOCATED OVER THE MN ARROWHEAD WITH A COLD
FRONT EXTENDING TO THE SSE THROUGH NW INTO CNTRL WI. VERY MILD SSW
FLOW AHEAD OF THE FRONT HAS PUSHED TEMPS INTO THE LOWER 40S ACROSS
MOST OF UPPER MI. GUSTY SW WINDS HAVE DEVELOPED BEHIND THE COLD
FRONT AS A 5MB/3HR PRES RISE MAX TRAILS THE FRONT OVER SRN MN.
RADARS INDICATED AREAS OF LIGHT PCPN OVER ERN MN INTO NW WI WITH NO
RETURNS TO THE EAST.
MAIN FCST CONCERNS ARE WINDS AND LAKE EFFECT SNOW POTENTIAL.
TODAY...MODELS HAVE BEEN CONSISTENT WITH THE LOW QUICKLY LIFTING
NORTHEAST TO JAMES BAY BY LATE TODAY. THIS WILL DRAG THE COLD FRONT
THROUGH THE CWA BY 18Z BRINGING THE STRONGEST ISALLOBARIC GRADIENT
THROUGH THE WEST HALF OF UPPER MICHIGAN THIS MORNING. WITH STRONG
CAA AND INCREASE IN MIXED LAYER DEPTH...GUSTY WINDS IN THE 25 TO 35
MPH RANGE ARE EXPECTED OVER MOST OF THE REGION. SINCE THE SW WINDS
ARE MAINLY PARALLEL TO THE KEWEENAW PENINSULA THE STRONGER GUSTS ARE
EXPECTED DURING THE AFTERNOON AS WINDS VEER MORE TO THE WSW. THIS
WOULD BRING THE STRONGEST GUSTS MAINLY ACROSS THE WESTERN SHORE OF
THE KEWEENAW. A WIND ADVISORY IS IN EFFECT WHICH HIGHLIGHTS THESE
LOCATIONS. BY THE TIME THAT WINDS VEER TO THE WEST WHICH WOULD FAVOR
LOCATIONS IN THE HIGHER TERRAIN AROUND CMX...THE GRADIENT WEAKENS.
LAKE INDUCED CAPE VALUES CLIMB QUICKLY TO AROUND 300-400 J/KG BY
LATE AFTERNOON AS 850 MB TEMPS FALL TO NEAR -15C. THE STRONGEST LOW
LEVEL CONVERGENCE AND GREATEST LES IS EXPECTED TO FOCUS TOWARD THE
NRN PORTION OF THE KEWEENAW....FROM CMX NORTHWARD.
TONIGHT...INSTABILITY OVER THE LAKE WILL INCREASE AS 850 MB TEMPS
DROP TO AROUND -18C. THE HIGHER RES MODELS SUGGEST THAT EVEN AS THE
WINDS OVER WRN LAKE SUPERIOR VEER MORE TO THE NW...LAKE INDUCED
TROUGHING WILL KEEP THE CONVERGENT WINDS OVER THE KEWEENAW. EVEN
THOUGH INVERSION HEIGHTS ARE ONLY FCST NEAR 4K FT...WITH THE
MOISTURE DEPTH TO AT LEAST 7K FT...AT LEAST MODERATE INTENSITY LES
IS EXPECTED THAT COULD BRING 2 TO 4 INCHES TO LOCATIONS FROM NE
ONTONAGON COUNTY THROUGH THE HIGHER TERRAIN OF THE KEWEENAW
PENINSULA. A LES ADVISORY WAS POSTED WHICH EXTENDS THROUGH SUNDAY
NIGHT(DETAILS IN SUBSEQUENT DISCUSSION).
A SHORTWAVE MOVING TOWARD THE GREAT LAKE FROM THE CNTRL PLAINS ALONG
WITH UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 170 KT 300 MB
JET INTO NRN ONTARIO WILL ALSO SUPPORT AN AREA OF LIGHT SNOW THAT
WILL GRAZE THE SE PORTIONS OF THE CWA. SINCE THE HEAVIER PCPN IS
EXPECTED TO THE SOUTH...ACCUMULATIONS ARE EXPECTED TO REMAIN BELOW
AN INCH.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 534 AM EST SAT JAN 12 2013
AREA WILL BE ENTERING BACK INTO A MORE WINTER TIME PATTERN
TODAY...WHICH WILL CONTINUE THROUGH THE LONG TERM PERIOD.
SYSTEM MOVING THROUGH THE LOWER GREAT LAKES TONIGHT INTO SUNDAY HAS
HAS SHIFTED A LITTLE MORE TO THE NORTHWEST OVER THE LAST FEW RUNS
AND NOW BRUSHES THE COUNTIES NEAR LAKE MICHIGAN WITH SOME LIGHT SNOW
SUNDAY MORNING. THIS NORTHWEST SHIFT HAS CAUSES THE DEEPER MOISTURE
WITH A LEFT OVER SHORTWAVE FROM THE LOW CURRENTLY IN MN TO REMAIN
JUST TO THE WEST OF LAKE SUPERIOR ON SUNDAY MORNING AND THE FIRST
PART OF THE AFTERNOON. THIS LEADS TO SOME CONCERN FOR THE INITIAL
LAKE EFFECT FROM LINGERING SURFACE TROUGH OVER SOUTHERN LAKE
SUPERIOR. SINCE THE COLD AIR SURGE EXPECTED TODAY INTO TONIGHT WILL
BE FAIRLY SHALLOW...IT WILL SETUP A VERY STRONG INVERSION TONIGHT
AROUND H800 OR 5KFT. THUS...DO EXPECT LAKE EFFECT TO BE OCCURRING
OVER THE WEST-NORTHWEST FAVORED LOCATIONS IN THE WESTERN U.P.
BUT HAVE SOME CONCERNS ON STRENGTH TO START THE PERIOD. ON THE
POSITIVE SIDE...THE BEST FORCING WILL BE FOCUSED IN THE DGZ...BUT
THERE IS SOME SHEAR IN THE CLOUD LAYER...SFC-H925 WINDS OUT OF THE
NORTHWEST AND H850 WINDS OUT OF THE WEST IN THE MORNING AND THEN
SOUTHWEST IN THE AFTERNOON. WONDERING IF THIS WILL KEEP THE FOCUS
AWAY FROM A DOMINATE BAND IN MORE GENERAL MULTIBAND LAKE EFFECT.
LAKE EFFECT SNOW PARAMETER...WHICH HAS DONE A GOOD JOB HIGHLIGHTING
THE FEW LAKE EFFECT EVENTS WE HAVE HAD THIS SEASON...KEEPS VALUES
LIMITED DURING THE MORNING HOURS AND WILL KEEP SNOWFALL AMOUNTS
LIGHTER.
ONCE THE SURFACE LOW SLIDES NORTHEAST INTO WESTERN QUEBEC SUNDAY
AFTERNOON AND EVENING...THEN THE SURFACE TROUGH WILL SLIDE SOUTH
SLIGHTLY LEADING TO LESS SHEAR AND RISING INVERSION HEIGHTS TO
6-7KFT DUE TO DEEPER MOISTURE IN MN BEING DRAGGED THROUGH THE
WESTERN CWA. LAKE EFFECT SNOW PARAMETER PEAKS TO 2 IN THIS
PERIOD...SO EXPECT INTENSITY OF THE LAKE EFFECT TO FOLLOW SUIT. AT
THIS POINT...THINK IT WILL BE IN NORTHWEST FAVORED LOCATIONS
ALTHOUGH HIGHER RESOLUTION MODELS ARE TRYING TO HINT AT ENHANCED
CONVERGENCE IN THE HOUGHTON/ONTONAGON/GOGEBIC COUNTY AREA. CHECKLIST
GIVES 3-5IN PER 12HRS FOR SUNDAY AND SUNDAY NIGHT AND THAT SEEMS TO
FIT WELL WITH THE GOING FORECAST...AS SNOW RATIOS WILL BE IN THE
20-30 TO 1 RANGE. WITH TOTAL SNOW FROM TONIGHT THROUGH SUNDAY NIGHT
OF 7 TO LOCALLY 14 INCHES...WILL ISSUE AN ADVISORY FOR KEWEENAW
THROUGH ONTONAGON COUNTIES. WILL NEED TO WATCH GOGEBIC COUNTY NEAR
THE PORCUPINE MOUNTAINS...AS ARE HINTS OF ENHANCED CONVERGENCE FOR
HIGHER SNOWFALL AMOUNTS THERE.
FARTHER EAST...WITH THE LIGHT SYNOPTIC SNOW LEAVING EARLY SUNDAY
AFTERNOON...TRANSITION WILL OCCUR TO LAKE EFFECT IN THE NORTHWEST
WIND BELTS IN THE AFTERNOON...AS THE SURFACE TROUGH SHIFTS WINDS.
THERE TOO...AMOUNTS WILL BE LIGHT TO MODERATE ON SUNDAY AFTERNOON
INTO THE EVENING...BUT COULD PEAK UP SOME AFTER MIDNIGHT WHEN THE
INVERSION HEIGHTS RISE. MAY NEED AN ADVISORY ON FUTURE SHIFTS FOR
THE SUN AFTERNOON/NIGHT PERIOD.
SURFACE TROUGH THEN SHIFTS NORTH ON MONDAY...PUSHING THE SNOW
OFFSHORE OVER THE EAST AND FOCUSES IT OVER THE KEWEENAW IN THE
WEST. INTENSITY SHOULD WEAKEN SOME AS THE DEEPER MOISTURE DEPARTS
AND INVERSION HEIGHTS DROP TO 5-6KFT. WITH THE CLOUD FOCUSED IN THE
DGZ...STILL SHOULD SEE GOOD SNOW RATIOS AND LIGHT SNOWFALL
ACCUMULATIONS IN THE 1-3 INCH RANGE FOR THE KEWEENAW.
SURFACE LOW DEVELOPS OVER EASTERN LAKE SUPERIOR MONDAY NIGHT AND
ENHANCES A SURFACE TROUGH OVER THE CENTRAL AND WESTERN PORTIONS OF
LAKE. MEANWHILE...DEEPER MOISTURE SLIDES THROUGH ASSOCIATED WITH A
SHORTWAVE MOVING THROUGH THE NORTHERN STREAM NORTHWEST FLOW. THERE
WILL LIKELY BE A STRONGER...DOMINATE LES BAND ASSOCIATED WITH THIS
TROUGH...BUT MODELS VARY ON THE EXACT LOCATION. AREA NEAR THE TIP OF
THE KEWEENAW WILL HAVE THE BEST CHANCE FOR SEEING THIS BAND LATE
MONDAY NIGHT INTO TUESDAY...SO WILL HIGHLIGHT HIGHER POPS/SNOWFALL
THERE. LES SHOULD DIMINISH TUESDAY AFTERNOON...AS WEAK RIDGING ALOFT
PRODUCES DRIER AIR AND WAA AHEAD OF THE NEXT SHORTWAVE.
THE NEXT SHORTWAVE AND ASSOCIATED CLIPPER LOW WILL MOVE ACROSS THE
CWA ON WEDNESDAY INTO WEDNESDAY EVENING. AS IS NORMALLY THE
CASE...THE GFS IS ON THE FAST SIDE AND THE ECMWF/GEM ARE ABOUT
6-12HRS BEHIND. WILL FOLLOW THAT IDEA FOR POPS AND THINK MOST AREAS
WILL SEE A DUSTING TO AN INCH OF SYNOPTIC SNOW.
POLAR VORTEX IS EXPECTED TO DROP SOUTH RIGHT BEHIND THIS WAVE AND
LEAD TO SOME OF THE COLDEST TEMPERATURES OF THE WINTER SEASON FOR
UPPER MICHIGAN. MODELS HAVE BEEN STRUGGLING WITH THIS PERIOD...DUE
TO THE PHASING OF THE NORTHERN/SOUTHERN STREAMS OF THE UPPER JET IN
THE EASTERN CONUS ON THURSDAY...BUT THE GENERAL IDEA OF COLD
WEATHER IS THERE. THE HPC PREFERRED BLEND OF ECMWF/ECENS MEAN SEEMS
TO BE THE WAY TO GO WITH THE GFS JUMPING 15C AT H850 FROM RUN TO
RUN. THIS COLD AIR...H850 TEMPS ON THE ECMWF IN THE MID -20S WILL
EASILY LEAD TO LAKE EFFECT SNOW IN THE NORTHWEST WIND LOCATIONS.
DELTA-T VALUES SHOULD BE FAIRLY IMPRESSIVE...IN THE UPPER 20S BUT
THE COLD AIR WILL PUSH THE DGZ TOWARDS THE SURFACE AND PRODUCE A
LESS FLUFFY /PLATES OR COLUMNS/ SNOW. WILL KEEP THE SAME IDEA AS
THE PREVIOUS SHIFT OF HIGH END LIKELY POPS FOR WEDNESDAY NIGHT INTO
FRIDAY FOR NORTHWEST AND EVENTUALLY WEST-NORTHWEST FAVORED
LOCATIONS. ONE FINAL ITEM TO NOTE DURING THIS PERIOD IS THE 00Z
GEM/GFS ARE BOTH SHOWING A CLIPPER MOVING THROUGH THE UPPER
MISSISSIPPI VALLEY ON THURSDAY INTO THURSDAY NIGHT...WHILE
THE ECMWF IS ABOUT A DAY LATER AND MAY BRUSH THE CWA.
HIGHS FOR THE PERIOD WILL BE IN THE TEENS TO MIDDLE 20S...WITH THE
COLDEST HIGHS EXPECTED ON THURSDAY/FRIDAY. LOWS WILL ALSO BE NEAR
NORMAL...WITH VALUES IN THE SINGLE DIGITS TO MIDDLE TEENS ABOVE
ZERO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1246 PM EST SAT JAN 12 2013
MVFR CONDITIONS ARE COMMON...EXCEPT HIGH END MVFR TO LOW END VFR
CEILINGS AT SAW /THANKS TO THE DOWNSLOPE CONDITIONS AT SAW/. STRONG
WSW GUSTS OF 25 TO 33KTS CONTINUE AT ALL 3 SITES...STRONGEST AT CMX
GIVEN THE HIGHER ELEVATION AND MORE FAVORABLE WIND DIRECTION...AND
LOCATION CLOSER TO THE EXITING SURFACE LOW. THE STRONG GUSTY WINDS
WILL DIMINISH SIGNIFICANTLY AROUND SUNSET...AS THE LOW QUICKLY
SHIFTS INTO WESTERN QUEBEC. SNOW SHOWERS EVIDENT ON THE DLH RADAR
WILL SLOWLY PUSH ACROSS W UPPER MI THIS AFTERNOON...WITH THE
CONTINUED STRONG WINDS BRINGING THE POTENTIAL FOR BLOWING SNOW TO
MAINLY CMX PRIOR TO 02Z. IFR TO LOW MVFR VIS CAN THEN BE EXPECTED TO
LINGER THROUGH THE MID MORNING HOURS AT CMX...WITH MAINLY MVFR
CONDITIONS TO VFR CONDITIONS AT IWD AND SAW RESPECTIVELY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 534 AM EST SAT JAN 12 2013
LOW PRESSURE ACROSS NE MN WILL MOVE NORTHEAST TO JAMES BAY LATE TODAY
BRINGING GALES ACROSS LAKE SUPERIOR. STRONG SW GALES OF 35 WILL
DEVELOP TOWARD DAYBREAK ACROSS THE WESTERN LAKE BEHIND THE COLD FRONT
AND INCREASE TO 40-45KTS. EXPECT THE GALES TO DIMINISH AS THE
STRONGEST WINDS SLOWLY EDGE SE...AS WINDS BEGIN TO TURN W BY LATE
AFTERNOON.
A TROUGH AVERAGING WILL LINGER ACROSS LAKE SUPERIOR THROUGH
SUNDAY...BEFORE SLOWLY WEAKENING AS STRONGER 30.4 INCH HIGH PRESSURE
EXPANDS ACROSS CENTRAL CANADA THROUGH THE CENTRAL PLAINS STATES
THROUGH MONDAY. NW WINDS COULD AGAIN GUST TO NEAR 30KTS OVER SE LS
SUNDAY NIGHT. LOW PRESSURE OVER MANITOBA AND ND TUESDAY NIGHT WILL
LIKELY PUSH ACROSS ONTARIO AND THE UPPER GREAT LAKES ON WEDNESDAY.
ANOTHER PERIOD OF SW-W 30-35KTS WINDS WILL BE POSSIBLE TUESDAY
AFTERNOON INTO THE EVENING HOURS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 5 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ001-003.
WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR MIZ001-003.
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST
MONDAY FOR MIZ002.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ162-
240>246-263>267.
LAKE MICHIGAN...
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LMZ248-250.
GALE WARNING UNTIL 5 PM EST THIS AFTERNOON FOR LMZ221.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...KF
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
643 AM EST SAT JAN 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 534 AM EST SAT JAN 12 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NW ONTARIO INTO THE SW CONUS AND A RIDGE OVER THE EAST RESULTING IN
SW FLOW FROM THE SRN PLAINS INTO THE WRN GREAT LAKES. A SHEARED
SHORTWAVE TROUGH WAS LIFTING NORTHEAST THROUGH NRN MN. AT THE
SFC...A 993 MB LOW WAS LOCATED OVER THE MN ARROWHEAD WITH A COLD
FRONT EXTENDING TO THE SSE THROUGH NW INTO CNTRL WI. VERY MILD SSW
FLOW AHEAD OF THE FRONT HAS PUSHED TEMPS INTO THE LOWER 40S ACROSS
MOST OF UPPER MI. GUSTY SW WINDS HAVE DEVELOPED BEHIND THE COLD
FRONT AS A 5MB/3HR PRES RISE MAX TRAILS THE FRONT OVER SRN MN.
RADARS INDICATED AREAS OF LIGHT PCPN OVER ERN MN INTO NW WI WITH NO
RETURNS TO THE EAST.
MAIN FCST CONCERNS ARE WINDS AND LAKE EFFECT SNOW POTENTIAL.
TODAY...MODELS HAVE BEEN CONSISTENT WITH THE LOW QUICKLY LIFTING
NORTHEAST TO JAMES BAY BY LATE TODAY. THIS WILL DRAG THE COLD FRONT
THROUGH THE CWA BY 18Z BRINGING THE STRONGEST ISALLOBARIC GRADIENT
THROUGH THE WEST HALF OF UPPER MICHIGAN THIS MORNING. WITH STRONG
CAA AND INCREASE IN MIXED LAYER DEPTH...GUSTY WINDS IN THE 25 TO 35
MPH RANGE ARE EXPECTED OVER MOST OF THE REGION. SINCE THE SW WINDS
ARE MAINLY PARALLEL TO THE KEWEENAW PENINSULA THE STRONGER GUSTS ARE
EXPECTED DURING THE AFTERNOON AS WINDS VEER MORE TO THE WSW. THIS
WOULD BRING THE STRONGEST GUSTS MAINLY ACROSS THE WESTERN SHORE OF
THE KEWEENAW. A WIND ADVISORY IS IN EFFECT WHICH HIGHLIGHTS THESE
LOCATIONS. BY THE TIME THAT WINDS VEER TO THE WEST WHICH WOULD FAVOR
LOCATIONS IN THE HIGHER TERRAIN AROUND CMX...THE GRADIENT WEAKENS.
LAKE INDUCED CAPE VALUES CLIMB QUICKLY TO AROUND 300-400 J/KG BY
LATE AFTERNOON AS 850 MB TEMPS FALL TO NEAR -15C. THE STRONGEST LOW
LEVEL CONVERGENCE AND GREATEST LES IS EXPECTED TO FOCUS TOWARD THE
NRN PORTION OF THE KEWEENAW....FROM CMX NORTHWARD.
TONIGHT...INSTABILITY OVER THE LAKE WILL INCREASE AS 850 MB TEMPS
DROP TO AROUND -18C. THE HIGHER RES MODELS SUGGEST THAT EVEN AS THE
WINDS OVER WRN LAKE SUPERIOR VEER MORE TO THE NW...LAKE INDUCED
TROUGHING WILL KEEP THE CONVERGENT WINDS OVER THE KEWEENAW. EVEN
THOUGH INVERSION HEIGHTS ARE ONLY FCST NEAR 4K FT...WITH THE
MOISTURE DEPTH TO AT LEAST 7K FT...AT LEAST MODERATE INTENSITY LES
IS EXPECTED THAT COULD BRING 2 TO 4 INCHES TO LOCATIONS FROM NE
ONTONAGON COUNTY THROUGH THE HIGHER TERRAIN OF THE KEWEENAW
PENINSULA. A LES ADVISORY WAS POSTED WHICH EXTENDS THROUGH SUNDAY
NIGHT(DETAILS IN SUBSEQUENT DISCUSSION).
A SHORTWAVE MOVING TOWARD THE GREAT LAKE FROM THE CNTRL PLAINS ALONG
WITH UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 170 KT 300 MB
JET INTO NRN ONTARIO WILL ALSO SUPPORT AN AREA OF LIGHT SNOW THAT
WILL GRAZE THE SE PORTIONS OF THE CWA. SINCE THE HEAVIER PCPN IS
EXPECTED TO THE SOUTH...ACCUMULATIONS ARE EXPECTED TO REMAIN BELOW
AN INCH.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 534 AM EST SAT JAN 12 2013
AREA WILL BE ENTERING BACK INTO A MORE WINTER TIME PATTERN
TODAY...WHICH WILL CONTINUE THROUGH THE LONG TERM PERIOD.
SYSTEM MOVING THROUGH THE LOWER GREAT LAKES TONIGHT INTO SUNDAY HAS
HAS SHIFTED A LITTLE MORE TO THE NORTHWEST OVER THE LAST FEW RUNS
AND NOW BRUSHES THE COUNTIES NEAR LAKE MICHIGAN WITH SOME LIGHT SNOW
SUNDAY MORNING. THIS NORTHWEST SHIFT HAS CAUSES THE DEEPER MOISTURE
WITH A LEFT OVER SHORTWAVE FROM THE LOW CURRENTLY IN MN TO REMAIN
JUST TO THE WEST OF LAKE SUPERIOR ON SUNDAY MORNING AND THE FIRST
PART OF THE AFTERNOON. THIS LEADS TO SOME CONCERN FOR THE INITIAL
LAKE EFFECT FROM LINGERING SURFACE TROUGH OVER SOUTHERN LAKE
SUPERIOR. SINCE THE COLD AIR SURGE EXPECTED TODAY INTO TONIGHT WILL
BE FAIRLY SHALLOW...IT WILL SETUP A VERY STRONG INVERSION TONIGHT
AROUND H800 OR 5KFT. THUS...DO EXPECT LAKE EFFECT TO BE OCCURRING
OVER THE WEST-NORTHWEST FAVORED LOCATIONS IN THE WESTERN U.P.
BUT HAVE SOME CONCERNS ON STRENGTH TO START THE PERIOD. ON THE
POSITIVE SIDE...THE BEST FORCING WILL BE FOCUSED IN THE DGZ...BUT
THERE IS SOME SHEAR IN THE CLOUD LAYER...SFC-H925 WINDS OUT OF THE
NORTHWEST AND H850 WINDS OUT OF THE WEST IN THE MORNING AND THEN
SOUTHWEST IN THE AFTERNOON. WONDERING IF THIS WILL KEEP THE FOCUS
AWAY FROM A DOMINATE BAND IN MORE GENERAL MULTIBAND LAKE EFFECT.
LAKE EFFECT SNOW PARAMETER...WHICH HAS DONE A GOOD JOB HIGHLIGHTING
THE FEW LAKE EFFECT EVENTS WE HAVE HAD THIS SEASON...KEEPS VALUES
LIMITED DURING THE MORNING HOURS AND WILL KEEP SNOWFALL AMOUNTS
LIGHTER.
ONCE THE SURFACE LOW SLIDES NORTHEAST INTO WESTERN QUEBEC SUNDAY
AFTERNOON AND EVENING...THEN THE SURFACE TROUGH WILL SLIDE SOUTH
SLIGHTLY LEADING TO LESS SHEAR AND RISING INVERSION HEIGHTS TO
6-7KFT DUE TO DEEPER MOISTURE IN MN BEING DRAGGED THROUGH THE
WESTERN CWA. LAKE EFFECT SNOW PARAMETER PEAKS TO 2 IN THIS
PERIOD...SO EXPECT INTENSITY OF THE LAKE EFFECT TO FOLLOW SUIT. AT
THIS POINT...THINK IT WILL BE IN NORTHWEST FAVORED LOCATIONS
ALTHOUGH HIGHER RESOLUTION MODELS ARE TRYING TO HINT AT ENHANCED
CONVERGENCE IN THE HOUGHTON/ONTONAGON/GOGEBIC COUNTY AREA. CHECKLIST
GIVES 3-5IN PER 12HRS FOR SUNDAY AND SUNDAY NIGHT AND THAT SEEMS TO
FIT WELL WITH THE GOING FORECAST...AS SNOW RATIOS WILL BE IN THE
20-30 TO 1 RANGE. WITH TOTAL SNOW FROM TONIGHT THROUGH SUNDAY NIGHT
OF 7 TO LOCALLY 14 INCHES...WILL ISSUE AN ADVISORY FOR KEWEENAW
THROUGH ONTONAGON COUNTIES. WILL NEED TO WATCH GOGEBIC COUNTY NEAR
THE PORCUPINE MOUNTAINS...AS ARE HINTS OF ENHANCED CONVERGENCE FOR
HIGHER SNOWFALL AMOUNTS THERE.
FARTHER EAST...WITH THE LIGHT SYNOPTIC SNOW LEAVING EARLY SUNDAY
AFTERNOON...TRANSITION WILL OCCUR TO LAKE EFFECT IN THE NORTHWEST
WIND BELTS IN THE AFTERNOON...AS THE SURFACE TROUGH SHIFTS WINDS.
THERE TOO...AMOUNTS WILL BE LIGHT TO MODERATE ON SUNDAY AFTERNOON
INTO THE EVENING...BUT COULD PEAK UP SOME AFTER MIDNIGHT WHEN THE
INVERSION HEIGHTS RISE. MAY NEED AN ADVISORY ON FUTURE SHIFTS FOR
THE SUN AFTERNOON/NIGHT PERIOD.
SURFACE TROUGH THEN SHIFTS NORTH ON MONDAY...PUSHING THE SNOW
OFFSHORE OVER THE EAST AND FOCUSES IT OVER THE KEWEENAW IN THE
WEST. INTENSITY SHOULD WEAKEN SOME AS THE DEEPER MOISTURE DEPARTS
AND INVERSION HEIGHTS DROP TO 5-6KFT. WITH THE CLOUD FOCUSED IN THE
DGZ...STILL SHOULD SEE GOOD SNOW RATIOS AND LIGHT SNOWFALL
ACCUMULATIONS IN THE 1-3 INCH RANGE FOR THE KEWEENAW.
SURFACE LOW DEVELOPS OVER EASTERN LAKE SUPERIOR MONDAY NIGHT AND
ENHANCES A SURFACE TROUGH OVER THE CENTRAL AND WESTERN PORTIONS OF
LAKE. MEANWHILE...DEEPER MOISTURE SLIDES THROUGH ASSOCIATED WITH A
SHORTWAVE MOVING THROUGH THE NORTHERN STREAM NORTHWEST FLOW. THERE
WILL LIKELY BE A STRONGER...DOMINATE LES BAND ASSOCIATED WITH THIS
TROUGH...BUT MODELS VARY ON THE EXACT LOCATION. AREA NEAR THE TIP OF
THE KEWEENAW WILL HAVE THE BEST CHANCE FOR SEEING THIS BAND LATE
MONDAY NIGHT INTO TUESDAY...SO WILL HIGHLIGHT HIGHER POPS/SNOWFALL
THERE. LES SHOULD DIMINISH TUESDAY AFTERNOON...AS WEAK RIDGING ALOFT
PRODUCES DRIER AIR AND WAA AHEAD OF THE NEXT SHORTWAVE.
THE NEXT SHORTWAVE AND ASSOCIATED CLIPPER LOW WILL MOVE ACROSS THE
CWA ON WEDNESDAY INTO WEDNESDAY EVENING. AS IS NORMALLY THE
CASE...THE GFS IS ON THE FAST SIDE AND THE ECMWF/GEM ARE ABOUT
6-12HRS BEHIND. WILL FOLLOW THAT IDEA FOR POPS AND THINK MOST AREAS
WILL SEE A DUSTING TO AN INCH OF SYNOPTIC SNOW.
POLAR VORTEX IS EXPECTED TO DROP SOUTH RIGHT BEHIND THIS WAVE AND
LEAD TO SOME OF THE COLDEST TEMPERATURES OF THE WINTER SEASON FOR
UPPER MICHIGAN. MODELS HAVE BEEN STRUGGLING WITH THIS PERIOD...DUE
TO THE PHASING OF THE NORTHERN/SOUTHERN STREAMS OF THE UPPER JET IN
THE EASTERN CONUS ON THURSDAY...BUT THE GENERAL IDEA OF COLD
WEATHER IS THERE. THE HPC PREFERRED BLEND OF ECMWF/ECENS MEAN SEEMS
TO BE THE WAY TO GO WITH THE GFS JUMPING 15C AT H850 FROM RUN TO
RUN. THIS COLD AIR...H850 TEMPS ON THE ECMWF IN THE MID -20S WILL
EASILY LEAD TO LAKE EFFECT SNOW IN THE NORTHWEST WIND LOCATIONS.
DELTA-T VALUES SHOULD BE FAIRLY IMPRESSIVE...IN THE UPPER 20S BUT
THE COLD AIR WILL PUSH THE DGZ TOWARDS THE SURFACE AND PRODUCE A
LESS FLUFFY /PLATES OR COLUMNS/ SNOW. WILL KEEP THE SAME IDEA AS
THE PREVIOUS SHIFT OF HIGH END LIKELY POPS FOR WEDNESDAY NIGHT INTO
FRIDAY FOR NORTHWEST AND EVENTUALLY WEST-NORTHWEST FAVORED
LOCATIONS. ONE FINAL ITEM TO NOTE DURING THIS PERIOD IS THE 00Z
GEM/GFS ARE BOTH SHOWING A CLIPPER MOVING THROUGH THE UPPER
MISSISSIPPI VALLEY ON THURSDAY INTO THURSDAY NIGHT...WHILE
THE ECMWF IS ABOUT A DAY LATER AND MAY BRUSH THE CWA.
HIGHS FOR THE PERIOD WILL BE IN THE TEENS TO MIDDLE 20S...WITH THE
COLDEST HIGHS EXPECTED ON THURSDAY/FRIDAY. LOWS WILL ALSO BE NEAR
NORMAL...WITH VALUES IN THE SINGLE DIGITS TO MIDDLE TEENS ABOVE
ZERO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 641 AM EST SAT JAN 12 2013
CONDITIONS AT SAW SHOULD QUICKLY IMPROVE INTO THE MVFR RANGE THIS
MORNING AT SAW AS WINDS VEER FROM THE S TO A MORE DOWNSLOPE SW
DIRECTION. A STRONG COLD FRONT WILL PUSH THROUGH THE AREA THIS
MORNING BRINGING GUSTY SOUTHWEST WINDS. THE STRONGEST GUSTS WILL
BE AT OROGRAPHICALLY FAVORED CMX WHERE GUSTS COULD REACH 40KTS. AS
TEMPERATURES FALL THROUGH THE DAY...LAKE EFFECT -SHSN SHOULD AFFECT
CMX WITH ANY LIGHT ACCUMULATIONS RESULTING IN BLSN BEFORE WINDS
BEGIN TO DIMINISH TOWARDS EVENING. LAKE EFFECT SNOW WITH PREDOMINANT
IFR VSBY IS EXPECTED TO CONTINUE THROUGH TONIGHT. AT IWD/SAW MAINLY
MVFR CONDITIONS SHOULD PREVAIL THROUGH THE FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 534 AM EST SAT JAN 12 2013
LOW PRESSURE ACROSS NE MN WILL MOVE NORTHEAST TO JAMES BAY LATE TODAY
BRINGING GALES ACROSS LAKE SUPERIOR. STRONG SW GALES OF 35 WILL
DEVELOP TOWARD DAYBREAK ACROSS THE WESTERN LAKE BEHIND THE COLD FRONT
AND INCREASE TO 40-45KTS. EXPECT THE GALES TO DIMINISH AS THE
STRONGEST WINDS SLOWLY EDGE SE...AS WINDS BEGIN TO TURN W BY LATE
AFTERNOON.
A TROUGH AVERAGING WILL LINGER ACROSS LAKE SUPERIOR THROUGH
SUNDAY...BEFORE SLOWLY WEAKENING AS STRONGER 30.4 INCH HIGH PRESSURE
EXPANDS ACROSS CENTRAL CANADA THROUGH THE CENTRAL PLAINS STATES
THROUGH MONDAY. NW WINDS COULD AGAIN GUST TO NEAR 30KTS OVER SE LS
SUNDAY NIGHT. LOW PRESSURE OVER MANITOBA AND ND TUESDAY NIGHT WILL
LIKELY PUSH ACROSS ONTARIO AND THE UPPER GREAT LAKES ON WEDNESDAY.
ANOTHER PERIOD OF SW-W 30-35KTS WINDS WILL BE POSSIBLE TUESDAY
AFTERNOON INTO THE EVENING HOURS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 5 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ001-003.
WIND ADVISORY FROM NOON TODAY TO 8 PM EST THIS EVENING FOR
MIZ001-003.
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST
MONDAY FOR MIZ002.
LAKE SUPERIOR...
GALE WARNING FROM 10 AM EST /9 AM CST/ THIS MORNING TO 10 PM EST
/9 PM CST/ THIS EVENING FOR LSZ240>246-265>267.
GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ162-
263-264.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR LMZ221-248-
250.
GALE WARNING FROM 11 AM THIS MORNING TO 9 PM EST THIS EVENING
FOR LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
535 AM EST SAT JAN 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 534 AM EST SAT JAN 12 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NW ONTARIO INTO THE SW CONUS AND A RIDGE OVER THE EAST RESULTING IN
SW FLOW FROM THE SRN PLAINS INTO THE WRN GREAT LAKES. A SHEARED
SHORTWAVE TROUGH WAS LIFTING NORTHEAST THROUGH NRN MN. AT THE
SFC...A 993 MB LOW WAS LOCATED OVER THE MN ARROWHEAD WITH A COLD
FRONT EXTENDING TO THE SSE THROUGH NW INTO CNTRL WI. VERY MILD SSW
FLOW AHEAD OF THE FRONT HAS PUSHED TEMPS INTO THE LOWER 40S ACROSS
MOST OF UPPER MI. GUSTY SW WINDS HAVE DEVELOPED BEHIND THE COLD
FRONT AS A 5MB/3HR PRES RISE MAX TRAILS THE FRONT OVER SRN MN.
RADARS INDICATED AREAS OF LIGHT PCPN OVER ERN MN INTO NW WI WITH NO
RETURNS TO THE EAST.
MAIN FCST CONCERNS ARE WINDS AND LAKE EFFECT SNOW POTENTIAL.
TODAY...MODELS HAVE BEEN CONSISTENT WITH THE LOW QUICKLY LIFTING
NORTHEAST TO JAMES BAY BY LATE TODAY. THIS WILL DRAG THE COLD FRONT
THROUGH THE CWA BY 18Z BRINGING THE STRONGEST ISALLOBARIC GRADIENT
THROUGH THE WEST HALF OF UPPER MICHIGAN THIS MORNING. WITH STRONG
CAA AND INCREASE IN MIXED LAYER DEPTH...GUSTY WINDS IN THE 25 TO 35
MPH RANGE ARE EXPECTED OVER MOST OF THE REGION. SINCE THE SW WINDS
ARE MAINLY PARALLEL TO THE KEWEENAW PENINSULA THE STRONGER GUSTS ARE
EXPECTED DURING THE AFTERNOON AS WINDS VEER MORE TO THE WSW. THIS
WOULD BRING THE STRONGEST GUSTS MAINLY ACROSS THE WESTERN SHORE OF
THE KEWEENAW. A WIND ADVISORY IS IN EFFECT WHICH HIGHLIGHTS THESE
LOCATIONS. BY THE TIME THAT WINDS VEER TO THE WEST WHICH WOULD FAVOR
LOCATIONS IN THE HIGHER TERRAIN AROUND CMX...THE GRADIENT WEAKENS.
LAKE INDUCED CAPE VALUES CLIMB QUICKLY TO AROUND 300-400 J/KG BY
LATE AFTERNOON AS 850 MB TEMPS FALL TO NEAR -15C. THE STRONGEST LOW
LEVEL CONVERGENCE AND GREATEST LES IS EXPECTED TO FOCUS TOWARD THE
NRN PORTION OF THE KEWEENAW....FROM CMX NORTHWARD.
TONIGHT...INSTABILITY OVER THE LAKE WILL INCREASE AS 850 MB TEMPS
DROP TO AROUND -18C. THE HIGHER RES MODELS SUGGEST THAT EVEN AS THE
WINDS OVER WRN LAKE SUPERIOR VEER MORE TO THE NW...LAKE INDUCED
TROUGHING WILL KEEP THE CONVERGENT WINDS OVER THE KEWEENAW. EVEN
THOUGH INVERSION HEIGHTS ARE ONLY FCST NEAR 4K FT...WITH THE
MOISTURE DEPTH TO AT LEAST 7K FT...AT LEAST MODERATE INTENSITY LES
IS EXPECTED THAT COULD BRING 2 TO 4 INCHES TO LOCATIONS FROM NE
ONTONAGON COUNTY THROUGH THE HIGHER TERRAIN OF THE KEWEENAW
PENINSULA. A LES ADVISORY WAS POSTED WHICH EXTENDS THROUGH SUNDAY
NIGHT(DETAILS IN SUBSEQUENT DISCUSSION).
A SHORTWAVE MOVING TOWARD THE GREAT LAKE FROM THE CNTRL PLAINS ALONG
WITH UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 170 KT 300 MB
JET INTO NRN ONTARIO WILL ALSO SUPPORT AN AREA OF LIGHT SNOW THAT
WILL GRAZE THE SE PORTIONS OF THE CWA. SINCE THE HEAVIER PCPN IS
EXPECTED TO THE SOUTH...ACCUMULATIONS ARE EXPECTED TO REMAIN BELOW
AN INCH.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 534 AM EST SAT JAN 12 2013
AREA WILL BE ENTERING BACK INTO A MORE WINTER TIME PATTERN
TODAY...WHICH WILL CONTINUE THROUGH THE LONG TERM PERIOD.
SYSTEM MOVING THROUGH THE LOWER GREAT LAKES TONIGHT INTO SUNDAY HAS
HAS SHIFTED A LITTLE MORE TO THE NORTHWEST OVER THE LAST FEW RUNS
AND NOW BRUSHES THE COUNTIES NEAR LAKE MICHIGAN WITH SOME LIGHT SNOW
SUNDAY MORNING. THIS NORTHWEST SHIFT HAS CAUSES THE DEEPER MOISTURE
WITH A LEFT OVER SHORTWAVE FROM THE LOW CURRENTLY IN MN TO REMAIN
JUST TO THE WEST OF LAKE SUPERIOR ON SUNDAY MORNING AND THE FIRST
PART OF THE AFTERNOON. THIS LEADS TO SOME CONCERN FOR THE INITIAL
LAKE EFFECT FROM LINGERING SURFACE TROUGH OVER SOUTHERN LAKE
SUPERIOR. SINCE THE COLD AIR SURGE EXPECTED TODAY INTO TONIGHT WILL
BE FAIRLY SHALLOW...IT WILL SETUP A VERY STRONG INVERSION TONIGHT
AROUND H800 OR 5KFT. THUS...DO EXPECT LAKE EFFECT TO BE OCCURRING
OVER THE WEST-NORTHWEST FAVORED LOCATIONS IN THE WESTERN U.P.
BUT HAVE SOME CONCERNS ON STRENGTH TO START THE PERIOD. ON THE
POSITIVE SIDE...THE BEST FORCING WILL BE FOCUSED IN THE DGZ...BUT
THERE IS SOME SHEAR IN THE CLOUD LAYER...SFC-H925 WINDS OUT OF THE
NORTHWEST AND H850 WINDS OUT OF THE WEST IN THE MORNING AND THEN
SOUTHWEST IN THE AFTERNOON. WONDERING IF THIS WILL KEEP THE FOCUS
AWAY FROM A DOMINATE BAND IN MORE GENERAL MULTIBAND LAKE EFFECT.
LAKE EFFECT SNOW PARAMETER...WHICH HAS DONE A GOOD JOB HIGHLIGHTING
THE FEW LAKE EFFECT EVENTS WE HAVE HAD THIS SEASON...KEEPS VALUES
LIMITED DURING THE MORNING HOURS AND WILL KEEP SNOWFALL AMOUNTS
LIGHTER.
ONCE THE SURFACE LOW SLIDES NORTHEAST INTO WESTERN QUEBEC SUNDAY
AFTERNOON AND EVENING...THEN THE SURFACE TROUGH WILL SLIDE SOUTH
SLIGHTLY LEADING TO LESS SHEAR AND RISING INVERSION HEIGHTS TO
6-7KFT DUE TO DEEPER MOISTURE IN MN BEING DRAGGED THROUGH THE
WESTERN CWA. LAKE EFFECT SNOW PARAMETER PEAKS TO 2 IN THIS
PERIOD...SO EXPECT INTENSITY OF THE LAKE EFFECT TO FOLLOW SUIT. AT
THIS POINT...THINK IT WILL BE IN NORTHWEST FAVORED LOCATIONS
ALTHOUGH HIGHER RESOLUTION MODELS ARE TRYING TO HINT AT ENHANCED
CONVERGENCE IN THE HOUGHTON/ONTONAGON/GOGEBIC COUNTY AREA. CHECKLIST
GIVES 3-5IN PER 12HRS FOR SUNDAY AND SUNDAY NIGHT AND THAT SEEMS TO
FIT WELL WITH THE GOING FORECAST...AS SNOW RATIOS WILL BE IN THE
20-30 TO 1 RANGE. WITH TOTAL SNOW FROM TONIGHT THROUGH SUNDAY NIGHT
OF 7 TO LOCALLY 14 INCHES...WILL ISSUE AN ADVISORY FOR KEWEENAW
THROUGH ONTONAGON COUNTIES. WILL NEED TO WATCH GOGEBIC COUNTY NEAR
THE PORCUPINE MOUNTAINS...AS ARE HINTS OF ENHANCED CONVERGENCE FOR
HIGHER SNOWFALL AMOUNTS THERE.
FARTHER EAST...WITH THE LIGHT SYNOPTIC SNOW LEAVING EARLY SUNDAY
AFTERNOON...TRANSITION WILL OCCUR TO LAKE EFFECT IN THE NORTHWEST
WIND BELTS IN THE AFTERNOON...AS THE SURFACE TROUGH SHIFTS WINDS.
THERE TOO...AMOUNTS WILL BE LIGHT TO MODERATE ON SUNDAY AFTERNOON
INTO THE EVENING...BUT COULD PEAK UP SOME AFTER MIDNIGHT WHEN THE
INVERSION HEIGHTS RISE. MAY NEED AN ADVISORY ON FUTURE SHIFTS FOR
THE SUN AFTERNOON/NIGHT PERIOD.
SURFACE TROUGH THEN SHIFTS NORTH ON MONDAY...PUSHING THE SNOW
OFFSHORE OVER THE EAST AND FOCUSES IT OVER THE KEWEENAW IN THE
WEST. INTENSITY SHOULD WEAKEN SOME AS THE DEEPER MOISTURE DEPARTS
AND INVERSION HEIGHTS DROP TO 5-6KFT. WITH THE CLOUD FOCUSED IN THE
DGZ...STILL SHOULD SEE GOOD SNOW RATIOS AND LIGHT SNOWFALL
ACCUMULATIONS IN THE 1-3 INCH RANGE FOR THE KEWEENAW.
SURFACE LOW DEVELOPS OVER EASTERN LAKE SUPERIOR MONDAY NIGHT AND
ENHANCES A SURFACE TROUGH OVER THE CENTRAL AND WESTERN PORTIONS OF
LAKE. MEANWHILE...DEEPER MOISTURE SLIDES THROUGH ASSOCIATED WITH A
SHORTWAVE MOVING THROUGH THE NORTHERN STREAM NORTHWEST FLOW. THERE
WILL LIKELY BE A STRONGER...DOMINATE LES BAND ASSOCIATED WITH THIS
TROUGH...BUT MODELS VARY ON THE EXACT LOCATION. AREA NEAR THE TIP OF
THE KEWEENAW WILL HAVE THE BEST CHANCE FOR SEEING THIS BAND LATE
MONDAY NIGHT INTO TUESDAY...SO WILL HIGHLIGHT HIGHER POPS/SNOWFALL
THERE. LES SHOULD DIMINISH TUESDAY AFTERNOON...AS WEAK RIDGING ALOFT
PRODUCES DRIER AIR AND WAA AHEAD OF THE NEXT SHORTWAVE.
THE NEXT SHORTWAVE AND ASSOCIATED CLIPPER LOW WILL MOVE ACROSS THE
CWA ON WEDNESDAY INTO WEDNESDAY EVENING. AS IS NORMALLY THE
CASE...THE GFS IS ON THE FAST SIDE AND THE ECMWF/GEM ARE ABOUT
6-12HRS BEHIND. WILL FOLLOW THAT IDEA FOR POPS AND THINK MOST AREAS
WILL SEE A DUSTING TO AN INCH OF SYNOPTIC SNOW.
POLAR VORTEX IS EXPECTED TO DROP SOUTH RIGHT BEHIND THIS WAVE AND
LEAD TO SOME OF THE COLDEST TEMPERATURES OF THE WINTER SEASON FOR
UPPER MICHIGAN. MODELS HAVE BEEN STRUGGLING WITH THIS PERIOD...DUE
TO THE PHASING OF THE NORTHERN/SOUTHERN STREAMS OF THE UPPER JET IN
THE EASTERN CONUS ON THURSDAY...BUT THE GENERAL IDEA OF COLD
WEATHER IS THERE. THE HPC PREFERRED BLEND OF ECMWF/ECENS MEAN SEEMS
TO BE THE WAY TO GO WITH THE GFS JUMPING 15C AT H850 FROM RUN TO
RUN. THIS COLD AIR...H850 TEMPS ON THE ECMWF IN THE MID -20S WILL
EASILY LEAD TO LAKE EFFECT SNOW IN THE NORTHWEST WIND LOCATIONS.
DELTA-T VALUES SHOULD BE FAIRLY IMPRESSIVE...IN THE UPPER 20S BUT
THE COLD AIR WILL PUSH THE DGZ TOWARDS THE SURFACE AND PRODUCE A
LESS FLUFFY /PLATES OR COLUMNS/ SNOW. WILL KEEP THE SAME IDEA AS
THE PREVIOUS SHIFT OF HIGH END LIKELY POPS FOR WEDNESDAY NIGHT INTO
FRIDAY FOR NORTHWEST AND EVENTUALLY WEST-NORTHWEST FAVORED
LOCATIONS. ONE FINAL ITEM TO NOTE DURING THIS PERIOD IS THE 00Z
GEM/GFS ARE BOTH SHOWING A CLIPPER MOVING THROUGH THE UPPER
MISSISSIPPI VALLEY ON THURSDAY INTO THURSDAY NIGHT...WHILE
THE ECMWF IS ABOUT A DAY LATER AND MAY BRUSH THE CWA.
HIGHS FOR THE PERIOD WILL BE IN THE TEENS TO MIDDLE 20S...WITH THE
COLDEST HIGHS EXPECTED ON THURSDAY/FRIDAY. LOWS WILL ALSO BE NEAR
NORMAL...WITH VALUES IN THE SINGLE DIGITS TO MIDDLE TEENS ABOVE
ZERO.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY MORNING)
ISSUED AT 534 AM EST SAT JAN 12 2013
AS SOUTHERLY WINDS INCREASE OVERNIGHT VISIBILITIES SHOULD SLOWLY
IMPROVE AT CMX AND SAW. HOWEVER...CIGS WILL GENERALLY REMAIN IN THE
LIFR RANGE. CONDITIONS SHOULD IMPROVE INTO THE MVFR RANGE ON
SATURDAY BEHIND A STRONG COLD FRONT PUSHING THROUGH THE AREA. STRONG
PRESSURE RISES AND A TIGHT PRESSURE GRADIENT WILL RESULT IN GUSTY
WEST TO SOUTHWEST WINDS DURING THE DAY. THE STRONGEST GUSTS WILL BE
AT OROGRAPHICALLY FAVORED CMX WHERE GUSTS COULD TOP 40KTS. AS
TEMPERATURES FALL THROUGH THE DAY LAKE EFFECT -SHSN SHOULD AFFECT
CMX WITH ANY LIGHT ACCUMULATIONS RESULTING IN BLSN BEFORE WINDS
BEGIN TO DIMINISH TOWARDS EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 534 AM EST SAT JAN 12 2013
LOW PRESSURE ACROSS NE MN WILL MOVE NORTHEAST TO JAMES BAY LATE TODAY
BRINGING GALES ACROSS LAKE SUPERIOR. STRONG SW GALES OF 35 WILL
DEVELOP TOWARD DAYBREAK ACROSS THE WESTERN LAKE BEHIND THE COLD FRONT
AND INCREASE TO 40-45KTS. EXPECT THE GALES TO DIMINISH AS THE
STRONGEST WINDS SLOWLY EDGE SE...AS WINDS BEGIN TO TURN W BY LATE
AFTERNOON.
A TROUGH AVERAGING WILL LINGER ACROSS LAKE SUPERIOR THROUGH
SUNDAY...BEFORE SLOWLY WEAKENING AS STRONGER 30.4 INCH HIGH PRESSURE
EXPANDS ACROSS CENTRAL CANADA THROUGH THE CENTRAL PLAINS STATES
THROUGH MONDAY. NW WINDS COULD AGAIN GUST TO NEAR 30KTS OVER SE LS
SUNDAY NIGHT. LOW PRESSURE OVER MANITOBA AND ND TUESDAY NIGHT WILL
LIKELY PUSH ACROSS ONTARIO AND THE UPPER GREAT LAKES ON WEDNESDAY.
ANOTHER PERIOD OF SW-W 30-35KTS WINDS WILL BE POSSIBLE TUESDAY
AFTERNOON INTO THE EVENING HOURS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 5 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ001-003.
WIND ADVISORY FROM NOON TODAY TO 8 PM EST THIS EVENING FOR
MIZ001-003.
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST
MONDAY FOR MIZ002.
LAKE SUPERIOR...
GALE WARNING FROM 10 AM EST /9 AM CST/ THIS MORNING TO 10 PM EST
/9 PM CST/ THIS EVENING FOR LSZ240>246-265>267.
GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ162-
263-264.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR LMZ221-248-
250.
GALE WARNING FROM 11 AM THIS MORNING TO 9 PM EST THIS EVENING
FOR LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...MZ
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1225 PM CST SAT JAN 12 2013
.UPDATE...
ISSUED AT 1212 PM CST SAT JAN 12 2013
COLD FRONT EXTENDS FROM JUST NORTHWEST OF FARMINGTON TO AROUND
SALEM ILLINOIS AT THIS TIME. LATEST MODEL GUIDANCE HAS STRENGTHENED
THE WARM NOSE ABOVE THE COLD AIR AT THE SURFACE FOR THIS
EVENING...AND THIS IS BEARING OUT PRETTY WELL IN AMDAR SOUNDINGS
FROM LAMBERT FIELD EARLIER THIS MORNING. RAP SOUNDINGS SHOW THE WARM
NOSE OVER THE STL METRO AREA WILL BE AROUND 7C THROUGH THE EVENING
HOURS...AND WITH THE COLD LAYER ONLY DROPPING TO BETWEEN -4C TO
-5C IT DOESN`T LOOK LIKE THERE`S GOING TO BE ENOUGH COLD AIR TO
FREEZE THE LIQUID ALOFT. FORECAST SOUNDINGS ALONG A LINE FROM
ROLLA TO ST LOUIS TO LITCHFIELD ARE VERY SIMILAR. THEREFORE AM
UPDATING THE FORECAST TO GO WITH MORE FREEZING RAIN THAN SLEET IN
THESE AREAS THIS EVENING AND OVERNIGHT. REMAINDER OF THE WEATHER
TYPES STILL LOOK GOOD WITH A SLEET/SNOW MIX OVER CENTRAL AND
NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS WHERE COLD AIR WILL BE
DEEPER...AND RAIN CHANGING TO FREEZING RAIN OVER SOUTHEAST
MISSOURI AND SOUTH CENTRAL ILLINOIS.
DEBATING WHETHER OR NOT TO EXTEND THE ADVISORY ANOTHER ROW OF
COUNTIES TO THE SOUTHEAST TO ACCOUNT FOR THE POTENTIAL OF MORE
FREEZING RAIN ACCUMULATION...AND WILL LIKELY HAVE TO EXTEND THE
TIME OF THE ADVISORY OUT BEYOND 06Z TONIGHT.
CARNEY
&&
.SHORT TERM...
ISSUED AT 330 AM CST SAT JAN 12 2013
(TODAY)
A STRONG CDFNT WILL MOVE THROUGH MOST OF THE CWA TODAY BEFORE IT
BEGINS TO STALL IN SERN MO LATER TODAY DUE TO A WAVE OF LOW
PRESSURE WHICH DVLPS UPSTREAM ALONG THE FRONT IN RESPONSE TO AN
UPPER LEVEL DISTURBANCE MOVING OVER THE BDRY IN TX/OK. MANY
LOCATIONS WILL EXPERIENCE NEARLY STEADY OR FALLING TEMPERATURES
THROUGH THE DAY BECAUSE OF THE STRENGTH OF THE CDFNT AND THE
TIMING OF ITS PASSAGE DURING DAYLIGHT HOURS.
STRONG ISENTROPIC ASCENT IS MOST PRONOUNCED ALONG THE 295-305K
SFCS THIS AFTN AHEAD OF AN APPROACHING SHORTWAVE. THIS ASCENT WILL
OCCUR IN THE PRESENCE OF A GREAT DEAL OF MOISTURE FOR MID-JANUARY.
IN PARTICULAR...STANDARDIZED ANOMALY PLOTS OF PW FROM THE 12/00Z
GFS AND 12/03Z SREF SHOW ANOMALIES OF BETWEEN +1 AND +4 STDDEV
ACROSS THE ENTIRE CWA WITH THE HIGHEST VALUES ACROSS THE SERN CWA
BY 00Z. THE NET RESULT OF THE FNTL PASSAGE TODAY ALONG WITH
SEVERAL HOURS OF ASCENT AND PLENTY OF MOISTURE WILL BE PCPN OF
VARIOUS TYPES OCCURRING FROM THIS AFTN THROUGH TONIGHT. THE BULK
OF THE PCPN AS WELL AS THE GREATEST VARIETY OF PTYPES WILL OCCUR
TONIGHT AND THIS IS DISCUSSED IN FURTHER DETAIL BELOW. FOR THIS
AFTN...BUFKIT PROFILES SUPPORT RAIN WHICH MAY BEGIN CHANGING TO
SNOW AND ICE PELLETS ACROSS THE FAR WRN AND NWRN CWA LATE IN THE
AFTN. SCT THUNDERSTORMS WILL ALSO BE POSSIBLE ACROSS THE SERN CWA
SINCE MODELS SHOW SOME MUCAPE ALONG WITH STRONG MOISTURE TRANSPORT
ALOFT.
KANOFSKY
&&
.LONG TERM...
ISSUED AT 357 AM CST SAT JAN 12 2013
(TONIGHT AND SUNDAY)
THE FORECAST PACKAGE...AS IT STANDS NOW...WILL BE DOMINATED BY WHAT
HAPPENS IN THIS PERIOD. BASIC PREMISE OF THE FORECAST REMAINS THE
SAME...BUT THERE HAVE BEEN SOME MODEL TRENDS IN SOME AREAS THAT
COULD MAKE A SIGNIFICANT IMPACT TO THE FORECAST.
MODELS CONTINUE TO SHOW SW UPPER LEVEL FLOW PATTERN WITH A
SIGNIFICANT PIECE OF ENERGY BREAKING APART FROM THE BASE OF THE MAIN
LONGWAVE TROF IN THE FOUR CORNERS REGION TODAY AND RACING NEWD THRU
OUR AREA THIS EVENING. IN ADDITION TO THE LIFT PROVIDED BY THIS
SHORTWAVE WILL BE SEVERAL OTHER STRONG LIFTING MECHANISMS FROM RIGHT
ENTRANCE REGION OF AN UPPER JET...FRONTOGENESIS AT H850-700...WAA...
AND CONVERGENCE FROM NOSE OF LO LEVEL JET...THAT WILL PROVIDE
INTENSE LIFT THRU THE COLUMN ACROSS A WIDESPREAD AREA THIS EVENING.
BUT ALREADY BY 06Z...MUCH OF THIS LIFT IS GONE IN AN INCREASINGLY
DRY COLUMN SEVERELY LIMITING PCPN POTENTIAL LATE TONIGHT AND INTO
SUNDAY MORNING.
THE MAIN MODEL TRENDS FROM 24HRS AGO ARE A STRONGER WEDGE OF WARM
AIR ALOFT...AND MORE PERSISTENT...AS WELL AS JUICIER MOISTURE TO
WORK WITH FROM THE S-SE WHERE PWATS WILL PUSH TO 1.4" WHICH IS
HIGHLY ANOMALOUS FOR MID JANUARY...OFTEN CLIMATOLOGICALLY THE
COLDEST AND BY CONSEQUENCE THE DRIEST TIME OF THE YEAR.
TAKE THE ABOVE AND COUPLE IT WITH THE FACT THAT THE MODELS SEEM TO
BE UNDERESTIMATING THE STRENGTH OF THE COLD AIR AT THE SFC BEHIND
CDFNT NOW PLOWING FROM KIRK-KJLN AT 09Z...COULD MAKE FOR A
POTENTIALLY DANGEROUS WINTRY WX EVENT. BY THIS MEANING THAT THE
ZONE OF MIXED WINTRY PCPN WILL PUSH FURTHER NWWD TOWARDS KUIN-KCOU
AND IT IS LOOKING INCREASINGLY LIKELY THAT A ZONE OF FZRA WILL PUSH
SEWD EDGING THE STL METRO AREA FROM THE NW AND EXTENDING SWWD ALG
I-44 AND NEWD NEAR I-55. THE MOSTLY SNOW ZONE...ROUGHLY ALG-NW FROM
A KUIN-KCOU LINE...IS EXPECTED TO RECEIVE 1-2"...WHILE AREAS FURTHER
SE WILL RECEIVE A POTPOURRI OF WINTRY TYPES...FROM FZRA TO SLEET
WITH SOME SNOW. LIGHT ICE AND SLEET/SNOW ACCUMS ARE EXPECTED BUT IT
WILL NOT TAKE MUCH TO CREATE PROBLEMS.
HAVE HOISTED A WINTER WX ADVISORY FOR THE WINTRY MIX AND SOMEWHAT
HEAVIER SNOW ACCUMS ACROSS ABOUT THE NW HALF OF THE FA FOR THIS
EVENING. PCPN MAY SNEAK IN SOONER...BUT DO NOT EXPECT ACCUMS AT
THIS TIME BEFORE 00Z AND THINGS SHOULD TAPER DOWN SIGNIFICANTLY
AFTER 06Z.
ALSO ADDED THUNDER AND HEAVY RAINFALL MENTION FOR AREAS SE OF STL
METRO BUT HELD OFF ON FFA FOR NOW WITH EXISTING DROUGHT AND LESS
THAN 2" OF RAINFALL EXPECTED. WILL LET DAY CREW TAKE A FINAL LOOK
ON THIS ITEM.
(MONDAY - TUESDAY)
COLD...BUT DRY...WX WILL PREVAIL FOR THIS PERIOD. ON TUESDAY...AN
UPPER LEVEL SHORTWAVE WILL SLIDE THRU AS THE BASE OF THE LONGWAVE
TROF MIGRATES E...BUT LIMITED MOISTURE TO WORK WITH TO LEAVE DRY FOR
NOW.
(WEDNESDAY - FRIDAY)
LONGWAVE UPPER TROF SLIDES TO THE ERN CONUS BUT DE-AMPLIFIES IN THE
PROCESS AND SO WILL GIVE TEMPS A CHANCE TO MODERATE A BIT. STILL
LOOKS DRY AT THIS TIME...WITH SOME MODEL SPREADS SUGGESTING LIGHT
PCPN POTENTIAL FOR THURSDAY...BUT NOT ENOUGH TO INCLUDE IN FCST AT
THIS TIME.
TES
&&
.AVIATION...
ISSUED AT 1151 AM CST SAT JAN 12 2013
DIFFICULT FORECAST DUE TO POTENTIAL FOR MIXED PRECIP THIS EVENING.
COLD FRONT IS MOVING THROUGH THE AREA AT THIS TIME...HOWEVER THE
COLD AIR IS VERY SHALLOW. CURRENT THINKING PRECIP SHOULD BE MOSTLY
SLEET AND/OR SNOW ACROSS CENTRAL AND NORTHEAST MISSOURI AND WEST
CENTRAL ILLINOIS...TRANSITIONING TO RAIN AND FREEZING RAIN WITH
SOME SLEET IN EASTERN MISSOURI AND SOUTHWEST ILLINOIS...WITH
MOSTLY RAIN IN SOUTHEAST MISSOURI AND SOUTH CENTRAL ILLINOIS UNTIL
BETWEEN 10Z-12Z SUNDAY. SOME LINGERING LIGHT WINTRY PRECIPITATION
IS LIKELY AFTER 12Z SUNDAY MORNING...MAINLY SOUTHEAST OF THE
I-44 CORRIDOR IN MISSOURI AND THE I-70 CORRIDOR IN ILLINOIS. LOW
MVFR AND IFR FLIGHT CONDITIONS WILL PREVAIL ONCE THE PRECIP STARTS
AND WILL LIKELY CONTINUE THROUGH MUCH OF THE DAY SUNDAY.
SPECIFICS FOR KSTL...
COLD FRONT IS SOUTH OF LAMBERT AT THIS TIME. NORTHWEST WIND AND
VFR WILL PREVAIL THROUGH MUCH OF THE AFTERNOON...BUT WILL SEE RAIN
MOVE INTO THE TERMINAL FROM THE SOUTH. INITIAL SURGE OF RAIN
SHOULD BE PRETTY LIGHT...BUT WILL SEE RAINFALL INTENSIFY WITH
FLIGHT CONDITIONS DROPPING TO IFR BETWEEN 00Z AND 02Z. EXPECTING
ALL LIQUID PRECIP TO CONTINUE UNTIL LATE EVENING WHEN TEMPERATURE
SHOULD DROP TO FREEZING. PREDOMINANT PRECIP TYPE LOOKS TO BE
FREEZING RAIN AFTER THIS. MAY SEE A LITTLE SLEET OR LIGHT SNOW MIXED
IN BEFORE THE PRECIPITATION ENDS BETWEEN 08Z AND 10Z. LOW MVFR/IFR
FLIGHT CONDITIONS WILL CONTINUE TO PREVAIL IN LIGHT FREEZING
DRIZZLE OR FOG INTO THE DAYLIGHT HOURS OF SUNDAY BEFORE ENDING BY
EARLY TO MID MORNING.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT CST
TONIGHT FOR AUDRAIN MO-BOONE MO-CALLAWAY MO-COLE MO-
CRAWFORD MO-FRANKLIN MO-GASCONADE MO-KNOX MO-LEWIS MO-
LINCOLN MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-
OSAGE MO-PIKE MO-RALLS MO-SHELBY MO-ST. CHARLES MO-ST.
LOUIS CITY MO-ST. LOUIS MO-WARREN MO.
IL...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT CST
TONIGHT FOR ADAMS IL-BROWN IL-CALHOUN IL-GREENE IL-JERSEY
IL-MACOUPIN IL-PIKE IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1205 AM CST SAT JAN 12 2013
...UPDATED AVIATION DISCUSSION...
.UPDATE...
/834 PM CST Fri Jan 11 2013/
Looking at the latest model runs for tomorrow`s potential
snowfall...some of the higher resolution models are hinting at a
potential band of snow that could develop further west of the main
area of precipitation, from east central KS into north central MO,
possibly including parts of the KC metro. Earlier SREF members,
specifically the ARW members, were the first to pick up on this
possibility and now the 00Z NAM and even RAP are picking up on this
as well. Frontogenesis progs and cross section analysis do indicate
the potential for locally banded snowfall developing somewhere over
eastern KS and western MO in the vicinity of a stalled 700-hPa
boundary. This would be highly sensitive to small-scale fluctuations
in the height field so it is not necessarily going to come to
fruition. However, a small potential is there for a narrow band of
1"-3" across this corridor, possibly as high as 4" in a few spots
given the banded nature.
With the very high uncertainty, will not make any changes to the
ongoing forecast and will let the overnight shift analyze the full
suite of 00Z models before making the final call on this potential
snow band. But for now, wanted to raise awareness that *if* the
trend of the NAM, RAP and SREF were to continue, then our current
snowfall forecast for the KC area could be too low.
Hawblitzel
&&
.DISCUSSION...
The main focus for the next three days centers on the potential for
accumulating snowfall Saturday night:
Tonight - Saturday:
The strong cold front that will be tracking through the forecast
area tonight through Saturday was situated from northeastern
Nebraska through northwestern Kansas. This front is expected to
start entering northwestern Missouri around midnight tonight and
then be through the forecast area by mid morning. The night will
start rather mild with decent mixing ahead of the front keeping
temperatures ahead of the front in the upper 40s and 50s.
Temperatures will fall into the 20s and 30s behind the front with
temperatures nearly steady during the day Saturday. In fact, we will
likely see our highs early in the day before the cold advection
overwhelms things. Highs on Saturday should range from the upper 20s
in far northwestern Missouri to the lower 40s in parts of central
Missouri.
Saturday night:
As the strong cold advection is occurring, a weak system will move
northwest out of the Southern Plains and track across Arkansas and
southern Missouri. This system will interact with a strong jet
stream moving across the region and for part of the night much of
the forecast area will be the right rear quadrant of the upper jet.
This will enable broad frontogenetic forcing leading to a brief
period of strong upward lift. This will lead to several hours of
snowfall across areas mainly east of Interstate 35. The heaviest
accumulations of snow should be over portions of central Missouri
where as much as 2 inches looks possible given the available
moisture, the intensity of the system and the short duration of the
event itself. Further west, across east central Kansas, west central
Missouri and northwestern Missouri accumulations will be less than
an inch with little or no accumulation expected across far
northwestern Missouri and extreme northeastern Kansas.
Sunday:
This system will be quick-hitting and is expected to be out of the
region by late Sunday morning. As the system exits, skies should
clear out but temperatures will continue to be cold with highs in
the 20s and 30s.
CDB
Medium Range (Monday through Friday)...
Through the medium range, the pattern will gradually transition from
deep troughing over the Plains and eastern Rockies to warmer, more
zonal flow throughout the CONUS. Temperatures on Monday and Tuesday
continue to look colder than average with chilly Canadian air
continuing to flow into the region, then will gradually rise to near
or just above normal for Wednesday through at least Thursday. There
is some degree of disagreement among the longer-range models on the
extent and progression of arctic air into the CONUS by the end of
the work week as a broad, deep trough edges across the Canadian
border, which could strongly impact the temperature forecast. If the
12z ECMWF verifies going into the weekend, very cold temperatures
could slide into the CWA, despite a current consensus of slightly
above normal temperatures for that period. Thus, this will be
something to monitor for significant changes as this time period
draws closer.
No precipitation is expected through this period, as surface high
pressure becomes semi-permanent across the central and southern
Plains and the split jet structure keeps systems confined to far
northern and southeastern portions of the country.
Laflin
&&
.AVIATION...
For the 06Z TAFs...cold front will move through the terminals within
the first couple hours of the forecast with winds veering from wsw
to nw. Pressure gradient remains tight both ahead and immediately
behind the front such that gusty winds expected for at least a few
hours after fropa. Satellite cloud trends and upstream ceilings are
not as pessimistic so will allow for generally VFR conditions
although a few hours of MVFR are expected at KSTJ.
Latest short range models now keying in on the increasing potential
for banded snow a bit further northwest...spreading from east
central KS through west central MO, including the KMCI/KMKC
terminals, shortly after sunset. Model fields suggest a setup
favoring banded snow which would result in a period of several hours
of moderate snow intensity and MVFR/IFR conditions. Since the snow
bands will likely be very narrow the heaviest bands could easily set
up and miss the terminals. However, feel the threat is such that a
PROB group was used to highlight the potential.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
155 AM CST SAT JAN 12 2013
.DISCUSSION...UPDATED THE FORECAST TO END THE WIND ADVISORY AND TO
LOWER LOW TEMPERATURES TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 1119 PM CST FRI JAN 11 2013/
AVIATION...06Z KGRI TAF. DRIER LOW TO MID LEVEL AIR IS HELPING
RESTORE VFR CONDITIONS AT THE TERMINAL AND ALTHOUGH TEMPORARY
MVFR CEILINGS CANNOT BE RULED OUT THROUGH 08Z...PREVAILING VFR
CONDITIONS ARE CURRENTLY FORECAST THROUGH THE NEXT 24 HOURS. THE
SURFACE WIND WILL REMAIN STRONG FROM THE NORTHWEST...SUSTAINED AT
AROUND 25KTS AND GUSTING NEAR 30KTS...TO START THE TAF
PERIOD...BUT DECREASE IN INTENSITY THEREAFTER. VISIBILITY
RESTRICTION IS NOT EXPECTED THROUGH THE NEXT 24 HOURS.
PREV DISCUSSION... /ISSUED 843 PM CST FRI JAN 11 2013/
UPDATE...FOG AND LIGHT FREEZING RAIN WHICH WERE OBSERVED AT
VARIOUS POINTS ACROSS THE CWA EARLIER THIS EVENING HAVE SINCE
DISSIPATED. WENT AHEAD AND REMOVED ANY SUCH WORDING FROM THE GRIDS
AND HWO. ANY REPORTS OF BLOWING DUST FROM ACROSS OUR KANSAS
COUNTIES HAVE ALSO CEASED SO WENT AHEAD AND REMOVED SUCH WORDING
FROM THE FORECAST. AS OF 02Z THE LOW LEVEL BAROCLINIC ZONE WAS
LOCATED FROM NEAR KLNK...TO NEAR KHJH...TO NEAR KK61. THE SURFACE
WIND HAS TRANSITIONED TO THE NORTHWEST FOR MOST LOCATIONS ACROSS
OUR CWA AS A RESULT. LOW LEVEL PRESSURE RISES POST-FROPA ARE
INDUCING AN INCREASING LOW LEVEL PRESSURE GRADIENT ACROSS MUCH OF
THE CWA AT THIS HOUR...WITH THE STRONGEST PRESSURE RISES BEING
OBSERVED THROUGH THE TRI-CITIES AREA. A THIN CORRIDOR OF SUSTAINED
WIND NEAR 25KTS IS BEING OBSERVED FROM KAUH...TO KHSI...TO
KGRI...AND SOUTH TO KK82...WITH A SUSTAINED WIND CLOSER TO THE
15-20KT RANGE AT LOCATIONS FARTHER EAST AND WEST. SHORT TERM
GUIDANCE FROM THE RAP SUGGESTS THE LOW LEVEL PRESSURE RISES SHOULD
DIMINISH ACROSS MUCH OF OUR AREA HEADING INTO THE OVERNIGHT HOURS
AND WITH A RESULTANT DECREASE IN THE LOW LEVEL PRESSURE
GRADIENT...THE LOW LEVEL WIND FIELD SHOULD ALSO DIMINISH IN
INTENSITY. THIS IS A SOLUTION ALSO SUPPORTED BY THE NAM AND
OPERATIONAL GFS. THE ONLY EXCEPTION MAY BE ACROSS OUR FAR
NORTH/NORTHEASTERN CWA WHERE THE INCREASED LOW LEVEL PRESSURE
GRADIENT MAY REMAIN INTACT FOR A FEW HOURS LONGER...THUS ALLOWING
FOR A SOMEWHAT STRONGER WIND HEADING INTO THE EARLY MORNING HOURS
SATURDAY. GIVEN ALL THIS...WENT AHEAD AND CANCELLED THE WIND
ADVISORY WHICH WAS IN EFFECT FOR SOME OF OUR KANSAS COUNTIES. ALSO
WENT AHEAD AND PUSHED THE WIND ADVISORY...IN EFFECT FOR OUR
NEBRASKA COUNTIES...NORTH OF I-80 WHERE THE STRONGER LOW LEVEL
PRESSURE GRADIENT IS EXPECTED TO LINGER LONGER. THIS IS A DECISION
WHICH SEEMS A BIT SHAKY RIGHT NOW GIVEN THAT THE TRI-CITIES HAVE
SEEN A DRASTIC INCREASE IN WIND SPEED IN THE LAST HOUR BUT
AGAIN...THE CURRENT BELIEF IS THAT THE WIND WILL DIMINISH WITHIN
ANOTHER HOUR ACROSS THE TRI-CITIES..LEAVING ONLY OUR FAR
NORTH/NORTHEAST AT AN INCREASED RISK OF OBSERVING A WIND WHICH
MEETS WIND ADVISORY CRITERIA. ALSO WENT AHEAD AND TWEAKED HOURLY
TEMPERATURE...DEWPOINT AND SKY GRIDS TO BETTER REFLECT CURRENT
TRENDS.
PREV DISCUSSION... /ISSUED 621 PM CST FRI JAN 11 2013/
UPDATE...EVENING UPPER AIR ANALYSIS PER RAP ANALYSIS DATA
INDICATES LONGWAVE TROUGHING OVER THE WESTERN HALF OF THE
CONUS...WITH RIDGING OVER THE EAST. MID AND UPPER LEVEL JET ENERGY
EXTENDS FROM THE FOUR CORNERS REGION...NORTHEAST ACROSS THE
CENTRAL PLAINS...AND THEN FARTHER NORTHEAST INTO SOUTHERN AND
SOUTHEASTERN CANADA. MID AND UPPER TROPOSPHERIC FLOW IS QUITE
STRONG OVER OUR AREA AS A RESULT...MAXING OUT AT AROUND 150KTS PER
23Z RAP ANALYSIS SOUNDING DATA FROM KGRI. ITS WORTH NOTING THAT
THE LOWER TROPOSPHERE IS ALSO EXHIBITING VERY STRONG
FLOW...50-55KTS ALL THE WAY TO THE TOP OF THE LOW LEVEL INVERSION
NEAR 800MB. WATER VAPOR IMAGERY INDICATES A CLOSED MID LEVEL LOW
OVER WESTERN WYOMING. A MID LEVEL SHORT WAVE IS ALSO NOTED OVER
THE CENTRAL HIGH PLAINS...ADVANCING NORTHEAST ACROSS THE REGION
ALONG THE EASTERN PERIPHERY OF THE CLOSED MID LEVEL LOW. WATER
VAPOR IMAGERY ALSO INDICATES INCREASED VALUES OF MID LEVEL
MOISTURE EXTENDING FROM WEST-TEXAS...NORTHEAST INTO THE CENTRAL
PLAINS AND MID TO UPPER MISSISSIPPI VALLEY. A MID LEVEL DRY
INTRUSION IS ALSO NOTED EXTENDING FROM THE FOUR CORNERS REGION
NORTHEAST INTO THE CENTRAL HIGH PLAINS. AT THE SURFACE A ~992MB
LOW IS NOTED BETWEEN KMCK AND KHLC...WITH AN ASSOCIATED FRONTAL
BOUNDARY EXTENDING EAST/NORTHEAST FROM THE LOW ACROSS CENTRAL AND
NORTHEASTERN NEBRASKA...AND A COLD FRONT EXTENDING WEST/SOUTHWEST
FROM THE LOW INTO NORTHWESTERN KANSAS AND SOUTHEASTERN COLORADO. A
DRY LINE IS ALSO NOTED EXTENDING SOUTH FROM THE LOW ACROSS WESTERN
KANSAS.
BLOWING DUST REMAINED EVIDENT ON VISIBLE SATELLITE IMAGERY UNTIL
SUNSET THIS EVENING BUT AT THIS TIME HAVE NO REASON TO BELIEVE IT
HAS SUBSIDED AS GUSTY WINDS AND MINOR VISIBILITY RESTRICTIONS ARE
STILL BEING REPORTED FROM KPHG TO KHLC. THAT BEING SAID...GIVEN
THE LINGERING SNOWPACK AND WET GROUNDS ACROSS OUR AREA IT APPEARS
UNLIKELY VISIBILITY RESTRICTIONS WILL WORSEN THROUGH THE NEXT
COUPLE OF HOURS...AND WITH VISIBILITY GREATER THAN 1 1/2SM AT
KPHG...AM COMFORTABLE WITH THE BLOWING DUST MENTION IN THE CURRENT
WIND ADVISORY AND HWO. NO PLANS FOR A FORMAL BLOWING DUST ADVISORY
AT THIS TIME.
A THIN CORRIDOR OF DENSE FOG HAS DEVELOPED ALONG THE LOW LEVEL
BAROCLINIC ZONE CURRENTLY PUSHING ACROSS THE CWA. KHSI DROPPED TO
1/4SM FOR A BRIEF TIME THIS AFTERNOON...WITH LOCATIONS FROM KAUH
TO OSCEOLA AND KJYR ALSO REPORTING SIGNIFICANT VISIBILITY
RESTRICTIONS IN FOG THROUGH THE PAST COUPLE OF HOURS. WHAT FOG IS
REALIZED DOES NOT LAST LONG AS IT CONTINUES TO MOVE EAST...BUT
WENT AHEAD AND INSERTED PATCHY DENSE FOG IN THE GRIDS THROUGH 01Z
TO ACCOUNT FOR ONGOING ACTIVITY.
MID LEVEL THERMAL ADVECTION AND MODEST DPVA AHEAD OF THE MID LEVEL
SHORT WAVE OVER THE CENTRAL HIGH PLAINS IS PROMOTING WIDESPREAD
PRECIPITATION OVER WESTERN NEBRASKA...WITH SOME OF THIS
PRECIPITATION MANAGING TO CLIP FAR WEST/NORTHWESTERN PORTIONS OF
OUR CWA IN THE LAST HOUR. PROXIMITY SOUNDINGS FROM OUR
WEST/NORTHWEST CWA PER RAP ANALYSIS DATA SUGGESTS AN ELEVATED WARM
LAYER EXISTS BETWEEN 850 AND 800MB...AND PERIODIC LIGHT FREEZING
RAIN WAS REPORTED IN DAWSON COUNTY IN THE LAST HOUR. GIVEN THE
CURRENT RETURNS FROM KUEX...ANY FREEZING RAIN THAT IS REALIZED
SHOULD REMAIN VERY LIGHT AND SHOULD NOT PRODUCE MUCH IN THE WAY OF
ICE ACCUMULATION. THAT BEING SAID...FELT MORE COMFORTABLE
INTRODUCING LIGHT FREEZING RAIN WORDING TO THE GRIDS AND
HWO...THROUGH 01Z...FOR OUR FAR WEST/NORTHWEST CWA.
WIND ADVISORIES ACROSS OUR AREA REMAIN INTACT WITH NO CHANGES MADE
AT THIS TIME. THOSE HEADLINES WILL BE EVALUATED AND POTENTIALLY
ADJUSTED LATER THIS EVENING. REMAINDER OF THE FORECAST REMAINS IN
GOOD SHAPE...WITH ONLY MINOR TWEAKS MADE TO HOURLY
TEMPERATURE...WIND...AND DEWPOINT GRIDS TO BETTER REFLECT REALITY.
PREV DISCUSSION... /ISSUED 405 PM CST FRI JAN 11 2013/
SHORT TERM...NOW THROUGH SATURDAY
WINTERS COLD RETURNS TO THE CNTRL PLAINS TONIGHT WITH A PERIOD OF
STRONG WIND GUSTS IN THE TRANSITION...
AN SPS WAS ISSUED AT 2032Z FOR THE BLOWING DUST AND WILL PROBABLY
BE UPDATED BY THE BOTTOM OF THE HOUR.
WIND ADVISORIES CONTINUE AS POSTED. NPW WAS UPDATED/SENT AT 324 PM
TO RAISE ADDITIONAL AWARENESS OF BLOWING DUST OVER KS.
NOW: STRONG COLD FRONT IS SAGGING SE THRU CNTRL NEB. IT WAS LAST
SEEN ON THE LNX 88D AT 1825Z JUST NW OF BBW. THE TIMING TOOL BRINGS
IT INTO GRI BY 2230Z. 992 MB LOW WAS TRACKING ALONG THE KS-NEB
BORDER...S OF WHERE IT WAS FCST 24 HRS AGO.
THE FRONT IS AHEAD OF SCHEDULE SO USED THE RAP FOR SHORT-TERM WINDS.
THE 18Z RAP SUGGESTS IT FINALLY CUTS NE THIS EVNG ACROSS ERN NEB.
BLOWING DUST: A BURST OF 33-41 KT WINDS HAS RESULTED IN A LARGE AREA
OF BLOWING DUST THAT ORIGINATED OVER ERN CO. TIMING TOOL WILL BRING
THIS INTO OUR KS COUNTIES AROUND 445 PM AND IT WILL CONTINUE UNTIL
WIND SHIFT ASSOCIATED WITH COLD FRONTAL PASSAGE.
CONTEMPLATED CANCELLING THE WIND ADVISORY FOR N-CNTRL KS SINCE WINDS
HAVE BEEN WELL BELOW ADVISORY SUSTAINED OR GUSTS. BUT GIVEN MULTIPLE
G40 KTS WITH THAT DUST...HAVE CONTINUED ADVISORY.
A LARGE AREA OF STRATUS IS EXPECTED TO SINK S BEHIND THE FRONT TNGT
IN THE WAKE OF THE DEPARTING LOW. HOW FAR S OVC EXTENDS REMAINS
UNCERTAIN GIVEN DOWNSLOPING WINDS WILL TEND TO BREAK IT UP.
WIND: 3 HR PRES RISES ARE ONLY 3 MB OVER THE NEB PANHANDLE AT 21Z.
THE NAM IS OVER ESTIMATING THIS BY 5 MB AND THE RAP BY 3 MB. THINK
THE TREND IS RIGHT WITH EXPANDING/INCREASING PRES RISES AS THE LOW
ACCELERATES NEWD THIS EVE...BUT THE MAGNITUDE MAY BE OVERDONE.
CONFIDENCE IS ABOVE AVERAGE FOR VERIFYING THE ADVISORY OVER N-CNTRL
KS AHEAD OF THE FRONT. IT/S TAKEN ALL DAY BUT IT WILL VERIFY
22Z-03Z. BEHIND THE FRONT HAVE YET TO SEE ADVISORY LEVEL WINDS
DEVELOP. LOW-LEVELS WILL BECOME UNSTABLE IN CAA THIS EVE AND BUT
THIS APPEARS A MARGINAL WIND EVENT SO VERIFYING NEB WIND ADVISORY IS
BELOW AVERAGE ALONG AND S OF I-80. BEST CHANCE FOR A ONE-TIME 45 MPH
GUST WILL BE N OF THE TRI-CITIES. THE BEST CHANCE FOR VERIFYING
ALONG AND S OF I-80 WILL PROBABLY BE A BRIEF PERIOD OF SUSTAINED
WINDS OF 30 MPH.
TNGT: M/CLOUDY WITH BLUSTERY NW WINDS. SOME FLURRIES OR BRIEF SHSN
WILL OCCUR 6PM-12AM IN PULSE OF CAA. TEMP GUIDANCE WAS IN GOOD
AGREEMENT AND USED THE CONSENSUS OF ALL GUIDANCE WHICH BASICALLY
PUTS TEMPS NEAR NORMAL.
SAT: A MIX OF CLOUDS/SUN. UNSURE HOW MUCH STRATOCU GETS TRAPPED
UNDER FRONTAL INVERSION. HAVE ALREADY INCREASED CLOUDS ABOVE
PREVIOUS GID FCST AND IF NAM BUFKIT IS RIGHT THAN WE WILL BE TOO
LOW ON CLOUD COVER. REGARDLESS...PATCHES JET STREAM CIRRUS WILL
KEEP THE SKY AT LEAST P/CLOUDY. STILL A BLUSTERY NW WIND WITH GUST
UP TO 30 MPH FORENOON. TEMPS ARE NAM 2M TEMPS WHICH IS CLOSE TO
THE PREVIOUS FCST...ABOUT 12F BELOW NORMAL.
LONG TERM...SATURDAY NIGHT THROUGH FRIDAY. THIS WILL LIKELY BE A
DRY PERIOD WITH TEMPERATURES GENERALLY WARMING THROUGH AT LEAST
WEDNESDAY. MORE UNCERTAINTY ENTERS THE PICTURE BY THURSDAY AND
FRIDAY.
SATURDAY NIGHT THROUGH MONDAY...A COLD AREA OF ARCTIC HIGH PRESSURE
WILL BEGIN TO SLIDE INTO THE PLAINS SATURDAY NIGHT INTO SUNDAY AND
REMAIN THROUGH AT LEAST MONDAY. THERE WILL BE A LARGE UPPER TROUGH
SITUATED OVER THE PLAINS BUT ALL OF THE MOISTURE WILL BE AT THE
LEADING EDGE OF THIS TROUGH AND WELL OFF TO OUR EAST. HIGH
TEMPERATURES WILL BE STUCK IN THE 20S ON SUNDAY AND POSSIBLY MONDAY
AS WELL. SOME AREAS THAT ARE COMPLETELY FREE OF SNOW COVER MAY REACH
THE LOWER 30S ON MONDAY.
TUESDAY AND WEDNESDAY...THE 12Z ECMWF PUSHES THE SFC HIGH OFF TO OUR
SOUTH ALLOWING FOR WEST SOUTHWEST DOWNSLOPE SFC WINDS. THE SHALLOW
COLD AIR WILL GRADUALLY MODERATE WITH HIGH TEMPERATURES BACK INTO
THE 30S ON TUESDAY AND PROBABLY 40S BY WEDNESDAY.
THURSDAY THROUGH FRIDAY...THERE IS A SUBSTANTIAL AMOUNT OF MODEL
UNCERTAINTY WITH REGARD TO TEMPERATURES. HOWEVER...THERE IS GOOD
MODEL AGREEMENT IN DRY CONDITIONS. THE ECMWF BRINGS A COLD FRONT
THROUGH WEDNESDAY NIGHT WITH STRONG COLD AIR ADVECTION ON THURSDAY.
THE 850 MB TEMPERATURES THURSDAY EVENING RANGE FROM -15C ON THE 12Z
ECMWF TO 5C ON THE 12Z GFS FOR A SIGNIFICANT 20C DEGREE SPREAD. THE
OFFICIAL FORECAST IS SOMEWHERE IN THE MIDDLE OF THESE TWO MODELS
CALLING FOR ABOVE FREEZING HIGHS IN THE UPPER 30S TO LOWER 40S.
HOWEVER...THESE HIGHS MAY VERY WELL BE TOO WARM. THE ONGOING
STRATOSPHERIC WARMING EVENT WILL LIKELY RESULT IN THE TRANSITION TO
A NEGATIVE ARCTIC OSCILLATION PATTERN...WHICH TENDS TO BRING THE
COLD AIR DOWN OUT OF CANADA INTO THE EASTERN TWO THIRDS OF THE
CONUS. THEREFORE...I WOULD LEAN MORE TOWARDS THE ECWMF AND THE
POSSIBILITY OF COLDER TEMPERATURES THAN WHAT WE ARE OFFICIALLY
CALLING FOR AS THIS BETTER FITS THE -AO PATTERN. IF THE 12Z ECMWF
COLDER TREND CONTINUES...WE WILL NEED TO BE LOWERING OUR THURSDAY
AND FRIDAY HIGH TEMPERATURES.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
DISCUSSION (UPDATE)...HEINLEIN
AVIATION/EARLIER UPDATES...BRYANT
SHORT TERM...HALBLAUB
LONG TERM...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1119 PM CST FRI JAN 11 2013
.AVIATION...06Z KGRI TAF. DRIER LOW TO MID LEVEL AIR IS HELPING
RESTORE VFR CONDITIONS AT THE TERMINAL AND ALTHOUGH TEMPORARY
MVFR CEILINGS CANNOT BE RULED OUT THROUGH 08Z...PREVAILING VFR
CONDITIONS ARE CURRENTLY FORECAST THROUGH THE NEXT 24 HOURS. THE
SURFACE WIND WILL REMAIN STRONG FROM THE NORTHWEST...SUSTAINED AT
AROUND 25KTS AND GUSTING NEAR 30KTS...TO START THE TAF
PERIOD...BUT DECREASE IN INTENSITY THEREAFTER. VISIBILITY
RESTRICTION IS NOT EXPECTED THROUGH THE NEXT 24 HOURS.
&&
.PREV DISCUSSION... /ISSUED 843 PM CST FRI JAN 11 2013/
UPDATE...FOG AND LIGHT FREEZING RAIN WHICH WERE OBSERVED AT
VARIOUS POINTS ACROSS THE CWA EARLIER THIS EVENING HAVE SINCE
DISSIPATED. WENT AHEAD AND REMOVED ANY SUCH WORDING FROM THE GRIDS
AND HWO. ANY REPORTS OF BLOWING DUST FROM ACROSS OUR KANSAS
COUNTIES HAVE ALSO CEASED SO WENT AHEAD AND REMOVED SUCH WORDING
FROM THE FORECAST. AS OF 02Z THE LOW LEVEL BAROCLINIC ZONE WAS
LOCATED FROM NEAR KLNK...TO NEAR KHJH...TO NEAR KK61. THE SURFACE
WIND HAS TRANSITIONED TO THE NORTHWEST FOR MOST LOCATIONS ACROSS
OUR CWA AS A RESULT. LOW LEVEL PRESSURE RISES POST-FROPA ARE
INDUCING AN INCREASING LOW LEVEL PRESSURE GRADIENT ACROSS MUCH OF
THE CWA AT THIS HOUR...WITH THE STRONGEST PRESSURE RISES BEING
OBSERVED THROUGH THE TRI-CITIES AREA. A THIN CORRIDOR OF SUSTAINED
WIND NEAR 25KTS IS BEING OBSERVED FROM KAUH...TO KHSI...TO
KGRI...AND SOUTH TO KK82...WITH A SUSTAINED WIND CLOSER TO THE
15-20KT RANGE AT LOCATIONS FARTHER EAST AND WEST. SHORT TERM
GUIDANCE FROM THE RAP SUGGESTS THE LOW LEVEL PRESSURE RISES SHOULD
DIMINISH ACROSS MUCH OF OUR AREA HEADING INTO THE OVERNIGHT HOURS
AND WITH A RESULTANT DECREASE IN THE LOW LEVEL PRESSURE
GRADIENT...THE LOW LEVEL WIND FIELD SHOULD ALSO DIMINISH IN
INTENSITY. THIS IS A SOLUTION ALSO SUPPORTED BY THE NAM AND
OPERATIONAL GFS. THE ONLY EXCEPTION MAY BE ACROSS OUR FAR
NORTH/NORTHEASTERN CWA WHERE THE INCREASED LOW LEVEL PRESSURE
GRADIENT MAY REMAIN INTACT FOR A FEW HOURS LONGER...THUS ALLOWING
FOR A SOMEWHAT STRONGER WIND HEADING INTO THE EARLY MORNING HOURS
SATURDAY. GIVEN ALL THIS...WENT AHEAD AND CANCELLED THE WIND
ADVISORY WHICH WAS IN EFFECT FOR SOME OF OUR KANSAS COUNTIES. ALSO
WENT AHEAD AND PUSHED THE WIND ADVISORY...IN EFFECT FOR OUR
NEBRASKA COUNTIES...NORTH OF I-80 WHERE THE STRONGER LOW LEVEL
PRESSURE GRADIENT IS EXPECTED TO LINGER LONGER. THIS IS A DECISION
WHICH SEEMS A BIT SHAKY RIGHT NOW GIVEN THAT THE TRI-CITIES HAVE
SEEN A DRASTIC INCREASE IN WIND SPEED IN THE LAST HOUR BUT
AGAIN...THE CURRENT BELIEF IS THAT THE WIND WILL DIMINISH WITHIN
ANOTHER HOUR ACROSS THE TRI-CITIES..LEAVING ONLY OUR FAR
NORTH/NORTHEAST AT AN INCREASED RISK OF OBSERVING A WIND WHICH
MEETS WIND ADVISORY CRITERIA. ALSO WENT AHEAD AND TWEAKED HOURLY
TEMPERATURE...DEWPOINT AND SKY GRIDS TO BETTER REFLECT CURRENT
TRENDS.
PREV DISCUSSION... /ISSUED 621 PM CST FRI JAN 11 2013/
UPDATE...EVENING UPPER AIR ANALYSIS PER RAP ANALYSIS DATA
INDICATES LONGWAVE TROUGHING OVER THE WESTERN HALF OF THE
CONUS...WITH RIDGING OVER THE EAST. MID AND UPPER LEVEL JET ENERGY
EXTENDS FROM THE FOUR CORNERS REGION...NORTHEAST ACROSS THE
CENTRAL PLAINS...AND THEN FARTHER NORTHEAST INTO SOUTHERN AND
SOUTHEASTERN CANADA. MID AND UPPER TROPOSPHERIC FLOW IS QUITE
STRONG OVER OUR AREA AS A RESULT...MAXING OUT AT AROUND 150KTS PER
23Z RAP ANALYSIS SOUNDING DATA FROM KGRI. ITS WORTH NOTING THAT
THE LOWER TROPOSPHERE IS ALSO EXHIBITING VERY STRONG
FLOW...50-55KTS ALL THE WAY TO THE TOP OF THE LOW LEVEL INVERSION
NEAR 800MB. WATER VAPOR IMAGERY INDICATES A CLOSED MID LEVEL LOW
OVER WESTERN WYOMING. A MID LEVEL SHORT WAVE IS ALSO NOTED OVER
THE CENTRAL HIGH PLAINS...ADVANCING NORTHEAST ACROSS THE REGION
ALONG THE EASTERN PERIPHERY OF THE CLOSED MID LEVEL LOW. WATER
VAPOR IMAGERY ALSO INDICATES INCREASED VALUES OF MID LEVEL
MOISTURE EXTENDING FROM WEST-TEXAS...NORTHEAST INTO THE CENTRAL
PLAINS AND MID TO UPPER MISSISSIPPI VALLEY. A MID LEVEL DRY
INTRUSION IS ALSO NOTED EXTENDING FROM THE FOUR CORNERS REGION
NORTHEAST INTO THE CENTRAL HIGH PLAINS. AT THE SURFACE A ~992MB
LOW IS NOTED BETWEEN KMCK AND KHLC...WITH AN ASSOCIATED FRONTAL
BOUNDARY EXTENDING EAST/NORTHEAST FROM THE LOW ACROSS CENTRAL AND
NORTHEASTERN NEBRASKA...AND A COLD FRONT EXTENDING WEST/SOUTHWEST
FROM THE LOW INTO NORTHWESTERN KANSAS AND SOUTHEASTERN COLORADO. A
DRY LINE IS ALSO NOTED EXTENDING SOUTH FROM THE LOW ACROSS WESTERN
KANSAS.
BLOWING DUST REMAINED EVIDENT ON VISIBLE SATELLITE IMAGERY UNTIL
SUNSET THIS EVENING BUT AT THIS TIME HAVE NO REASON TO BELIEVE IT
HAS SUBSIDED AS GUSTY WINDS AND MINOR VISIBILITY RESTRICTIONS ARE
STILL BEING REPORTED FROM KPHG TO KHLC. THAT BEING SAID...GIVEN
THE LINGERING SNOWPACK AND WET GROUNDS ACROSS OUR AREA IT APPEARS
UNLIKELY VISIBILITY RESTRICTIONS WILL WORSEN THROUGH THE NEXT
COUPLE OF HOURS...AND WITH VISIBILITY GREATER THAN 1 1/2SM AT
KPHG...AM COMFORTABLE WITH THE BLOWING DUST MENTION IN THE CURRENT
WIND ADVISORY AND HWO. NO PLANS FOR A FORMAL BLOWING DUST ADVISORY
AT THIS TIME.
A THIN CORRIDOR OF DENSE FOG HAS DEVELOPED ALONG THE LOW LEVEL
BAROCLINIC ZONE CURRENTLY PUSHING ACROSS THE CWA. KHSI DROPPED TO
1/4SM FOR A BRIEF TIME THIS AFTERNOON...WITH LOCATIONS FROM KAUH
TO OSCEOLA AND KJYR ALSO REPORTING SIGNIFICANT VISIBILITY
RESTRICTIONS IN FOG THROUGH THE PAST COUPLE OF HOURS. WHAT FOG IS
REALIZED DOES NOT LAST LONG AS IT CONTINUES TO MOVE EAST...BUT
WENT AHEAD AND INSERTED PATCHY DENSE FOG IN THE GRIDS THROUGH 01Z
TO ACCOUNT FOR ONGOING ACTIVITY.
MID LEVEL THERMAL ADVECTION AND MODEST DPVA AHEAD OF THE MID LEVEL
SHORT WAVE OVER THE CENTRAL HIGH PLAINS IS PROMOTING WIDESPREAD
PRECIPITATION OVER WESTERN NEBRASKA...WITH SOME OF THIS
PRECIPITATION MANAGING TO CLIP FAR WEST/NORTHWESTERN PORTIONS OF
OUR CWA IN THE LAST HOUR. PROXIMITY SOUNDINGS FROM OUR
WEST/NORTHWEST CWA PER RAP ANALYSIS DATA SUGGESTS AN ELEVATED WARM
LAYER EXISTS BETWEEN 850 AND 800MB...AND PERIODIC LIGHT FREEZING
RAIN WAS REPORTED IN DAWSON COUNTY IN THE LAST HOUR. GIVEN THE
CURRENT RETURNS FROM KUEX...ANY FREEZING RAIN THAT IS REALIZED
SHOULD REMAIN VERY LIGHT AND SHOULD NOT PRODUCE MUCH IN THE WAY OF
ICE ACCUMULATION. THAT BEING SAID...FELT MORE COMFORTABLE
INTRODUCING LIGHT FREEZING RAIN WORDING TO THE GRIDS AND
HWO...THROUGH 01Z...FOR OUR FAR WEST/NORTHWEST CWA.
WIND ADVISORIES ACROSS OUR AREA REMAIN INTACT WITH NO CHANGES MADE
AT THIS TIME. THOSE HEADLINES WILL BE EVALUATED AND POTENTIALLY
ADJUSTED LATER THIS EVENING. REMAINDER OF THE FORECAST REMAINS IN
GOOD SHAPE...WITH ONLY MINOR TWEAKS MADE TO HOURLY
TEMPERATURE...WIND...AND DEWPOINT GRIDS TO BETTER REFLECT REALITY.
PREV DISCUSSION... /ISSUED 405 PM CST FRI JAN 11 2013/
SHORT TERM...NOW THROUGH SATURDAY
WINTERS COLD RETURNS TO THE CNTRL PLAINS TONIGHT WITH A PERIOD OF
STRONG WIND GUSTS IN THE TRANSITION...
AN SPS WAS ISSUED AT 2032Z FOR THE BLOWING DUST AND WILL PROBABLY
BE UPDATED BY THE BOTTOM OF THE HOUR.
WIND ADVISORIES CONTINUE AS POSTED. NPW WAS UPDATED/SENT AT 324 PM
TO RAISE ADDITIONAL AWARENESS OF BLOWING DUST OVER KS.
NOW: STRONG COLD FRONT IS SAGGING SE THRU CNTRL NEB. IT WAS LAST
SEEN ON THE LNX 88D AT 1825Z JUST NW OF BBW. THE TIMING TOOL BRINGS
IT INTO GRI BY 2230Z. 992 MB LOW WAS TRACKING ALONG THE KS-NEB
BORDER...S OF WHERE IT WAS FCST 24 HRS AGO.
THE FRONT IS AHEAD OF SCHEDULE SO USED THE RAP FOR SHORT-TERM WINDS.
THE 18Z RAP SUGGESTS IT FINALLY CUTS NE THIS EVNG ACROSS ERN NEB.
BLOWING DUST: A BURST OF 33-41 KT WINDS HAS RESULTED IN A LARGE AREA
OF BLOWING DUST THAT ORIGINATED OVER ERN CO. TIMING TOOL WILL BRING
THIS INTO OUR KS COUNTIES AROUND 445 PM AND IT WILL CONTINUE UNTIL
WIND SHIFT ASSOCIATED WITH COLD FRONTAL PASSAGE.
CONTEMPLATED CANCELLING THE WIND ADVISORY FOR N-CNTRL KS SINCE WINDS
HAVE BEEN WELL BELOW ADVISORY SUSTAINED OR GUSTS. BUT GIVEN MULTIPLE
G40 KTS WITH THAT DUST...HAVE CONTINUED ADVISORY.
A LARGE AREA OF STRATUS IS EXPECTED TO SINK S BEHIND THE FRONT TNGT
IN THE WAKE OF THE DEPARTING LOW. HOW FAR S OVC EXTENDS REMAINS
UNCERTAIN GIVEN DOWNSLOPING WINDS WILL TEND TO BREAK IT UP.
WIND: 3 HR PRES RISES ARE ONLY 3 MB OVER THE NEB PANHANDLE AT 21Z.
THE NAM IS OVER ESTIMATING THIS BY 5 MB AND THE RAP BY 3 MB. THINK
THE TREND IS RIGHT WITH EXPANDING/INCREASING PRES RISES AS THE LOW
ACCELERATES NEWD THIS EVE...BUT THE MAGNITUDE MAY BE OVERDONE.
CONFIDENCE IS ABOVE AVERAGE FOR VERIFYING THE ADVISORY OVER N-CNTRL
KS AHEAD OF THE FRONT. IT/S TAKEN ALL DAY BUT IT WILL VERIFY
22Z-03Z. BEHIND THE FRONT HAVE YET TO SEE ADVISORY LEVEL WINDS
DEVELOP. LOW-LEVELS WILL BECOME UNSTABLE IN CAA THIS EVE AND BUT
THIS APPEARS A MARGINAL WIND EVENT SO VERIFYING NEB WIND ADVISORY IS
BELOW AVERAGE ALONG AND S OF I-80. BEST CHANCE FOR A ONE-TIME 45 MPH
GUST WILL BE N OF THE TRI-CITIES. THE BEST CHANCE FOR VERIFYING
ALONG AND S OF I-80 WILL PROBABLY BE A BRIEF PERIOD OF SUSTAINED
WINDS OF 30 MPH.
TNGT: M/CLOUDY WITH BLUSTERY NW WINDS. SOME FLURRIES OR BRIEF SHSN
WILL OCCUR 6PM-12AM IN PULSE OF CAA. TEMP GUIDANCE WAS IN GOOD
AGREEMENT AND USED THE CONSENSUS OF ALL GUIDANCE WHICH BASICALLY
PUTS TEMPS NEAR NORMAL.
SAT: A MIX OF CLOUDS/SUN. UNSURE HOW MUCH STRATOCU GETS TRAPPED
UNDER FRONTAL INVERSION. HAVE ALREADY INCREASED CLOUDS ABOVE
PREVIOUS GID FCST AND IF NAM BUFKIT IS RIGHT THAN WE WILL BE TOO
LOW ON CLOUD COVER. REGARDLESS...PATCHES JET STREAM CIRRUS WILL
KEEP THE SKY AT LEAST P/CLOUDY. STILL A BLUSTERY NW WIND WITH GUST
UP TO 30 MPH FORENOON. TEMPS ARE NAM 2M TEMPS WHICH IS CLOSE TO
THE PREVIOUS FCST...ABOUT 12F BELOW NORMAL.
LONG TERM...SATURDAY NIGHT THROUGH FRIDAY. THIS WILL LIKELY BE A
DRY PERIOD WITH TEMPERATURES GENERALLY WARMING THROUGH AT LEAST
WEDNESDAY. MORE UNCERTAINTY ENTERS THE PICTURE BY THURSDAY AND
FRIDAY.
SATURDAY NIGHT THROUGH MONDAY...A COLD AREA OF ARCTIC HIGH PRESSURE
WILL BEGIN TO SLIDE INTO THE PLAINS SATURDAY NIGHT INTO SUNDAY AND
REMAIN THROUGH AT LEAST MONDAY. THERE WILL BE A LARGE UPPER TROUGH
SITUATED OVER THE PLAINS BUT ALL OF THE MOISTURE WILL BE AT THE
LEADING EDGE OF THIS TROUGH AND WELL OFF TO OUR EAST. HIGH
TEMPERATURES WILL BE STUCK IN THE 20S ON SUNDAY AND POSSIBLY MONDAY
AS WELL. SOME AREAS THAT ARE COMPLETELY FREE OF SNOW COVER MAY REACH
THE LOWER 30S ON MONDAY.
TUESDAY AND WEDNESDAY...THE 12Z ECMWF PUSHES THE SFC HIGH OFF TO OUR
SOUTH ALLOWING FOR WEST SOUTHWEST DOWNSLOPE SFC WINDS. THE SHALLOW
COLD AIR WILL GRADUALLY MODERATE WITH HIGH TEMPERATURES BACK INTO
THE 30S ON TUESDAY AND PROBABLY 40S BY WEDNESDAY.
THURSDAY THROUGH FRIDAY...THERE IS A SUBSTANTIAL AMOUNT OF MODEL
UNCERTAINTY WITH REGARD TO TEMPERATURES. HOWEVER...THERE IS GOOD
MODEL AGREEMENT IN DRY CONDITIONS. THE ECMWF BRINGS A COLD FRONT
THROUGH WEDNESDAY NIGHT WITH STRONG COLD AIR ADVECTION ON THURSDAY.
THE 850 MB TEMPERATURES THURSDAY EVENING RANGE FROM -15C ON THE 12Z
ECMWF TO 5C ON THE 12Z GFS FOR A SIGNIFICANT 20C DEGREE SPREAD. THE
OFFICIAL FORECAST IS SOMEWHERE IN THE MIDDLE OF THESE TWO MODELS
CALLING FOR ABOVE FREEZING HIGHS IN THE UPPER 30S TO LOWER 40S.
HOWEVER...THESE HIGHS MAY VERY WELL BE TOO WARM. THE ONGOING
STRATOSPHERIC WARMING EVENT WILL LIKELY RESULT IN THE TRANSITION TO
A NEGATIVE ARCTIC OSCILLATION PATTERN...WHICH TENDS TO BRING THE
COLD AIR DOWN OUT OF CANADA INTO THE EASTERN TWO THIRDS OF THE
CONUS. THEREFORE...I WOULD LEAN MORE TOWARDS THE ECWMF AND THE
POSSIBILITY OF COLDER TEMPERATURES THAN WHAT WE ARE OFFICIALLY
CALLING FOR AS THIS BETTER FITS THE -AO PATTERN. IF THE 12Z ECMWF
COLDER TREND CONTINUES...WE WILL NEED TO BE LOWERING OUR THURSDAY
AND FRIDAY HIGH TEMPERATURES.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY UNTIL 1 AM CST SATURDAY FOR NEZ039>041-046>049.
KS...NONE.
&&
$$
AVIATION/UPDATES...BRYANT
SHORT...HALBLAUB
LONG...WESELY
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
859 PM EST SUN JAN 13 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE MIDWEST AND NOSE INTO THE OHIO
VALLEY FOR THE BEGINNING OF THE WEEK. A WEAK COLD FRONT WILL SKIRT
THE NORTHEAST OHIO VALLEY WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
COLD FRONT EXTENDS ACROSS THE FAR EASTERN COUNTIES AND WILL MOVE
OUT OF THE AREA IN THE NEXT COUPLE OF HOURS. RADAR SHOWS A SHARP
EDGE TO THE RAIN WHICH IS LAGGING THE FRONT BY A FEW HOURS. EXPECT
THE RAIN TO COME TO AN END BY 06Z. WITH THIS QUICK CUTOFF IT
APPEARS THAT PRECIPITATION WILL END BEFORE TEMPERATURES ARE COLD
ENOUGH FOR ANY WINTRY MIX. TIGHT GRADIENT IMMEDIATELY BEHIND THE
COLD FRONT HAS RESULT IN GUSTY WINDS. THESE SHOULD GRADUALLY
DIMINISH AS GRADIENT RELAXES. SATELLITE SHOWS CLEARING WORKING
INTO WESTERN INDIANA. RAP FORECASTS SEEM TO HAVE A REASONABLE
HANDLE ON THIS LOW LEVEL MOISTURE. THIS SUGGESTS THAT CLEARING
WILL WORK INTO THE FORECAST AREA LATER TONIGHT. FORECAST LOWS LOOK
REASONABLE WITH SOME MINOR ADJUSTMENTS TO TEMPERATURE DROP.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
I WAS UNABLE TO GO AS LOW ON THE CLOUD COVER WITH THE HIGH
PRESSURE BUILDING IN AS I WOULD LIKE. THOUGHT THE MOISTURE
BUILDING IN FROM THE NORTHWEST ON TUESDAY AND THE INCREASED
MOISTURE FROM THE SOUTHEAST ON MONDAY WOULD BATTLE FOR AT LEAST
SOME CLOUD COVER OVER THE REST OF THE CWA FOR SOME POINT IN TIME.
A VORTICITY MAXIMA IS NOTED SOMEWHAT AT H5 AND WILL SKIRT
SOUTHEAST CWA MONDAY EVENING...INCREASING THE THREAT FOR A PASSING
SNOW SHOWER FOR JUST A FEW COUNTIES SOUTH OF CHILLICOTHE AND EAST
OF MAYSVILLE. BOTH NAM AND GFS ARE HINTING AT A WEAK SHORTWAVE
WITH THIS VORT IN THE MEAN SOUTHWEST FLOW.
HIGH PRESSURE STRENGTHENING IN THE WAKE OF THE COLD FRONT WILL
HELP USHER IN MORE SEASONAL AND SIGNIFICANTLY COLDER TEMPERATURES
TO THE REGION.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
FORECAST PERIOD BEGINS WITH SFC HIGH PRESSURE RIDGING OVER THE FA.
THIS RIDGING GETS SHUNTED E QUICKLY ON WEDNESDAY AS A CDFNT SWINGS
THRU THE GREAT LAKES WED AFTN. MODELS ARE KEEPING THE BEST LIFT N OF
THE FA WITH THIS SYSTEM...SO KEPT THE FCST DRY. HIGH PRESSURE BUILDS
BACK INTO THE OH AND TN VALLEYS THU INTO FRI.
ENERGY KEEPS RUNNING THROUGH THE SUBTLE ERN U.S. LONGWAVE TROF OVER
THE WEEKEND. GFS AND ECMWF DIFFER ON THE STRENGTH OF A SYSTEM ON
SATURDAY....BUT BOTH PUSH COOLER AIR IN ON SUNDAY WITH A TRAILING
COLD FRONT. ONCE AGAIN THE MOISTURE IS LOOKING LIMITED FOR
SUNDAY...SO KEPT THE FCST DRY.
AS FOR TEMPERATURES...THE HIGH PRESSURE RIDGE ON WEDNESDAY WILL
ALLOW HIGHS TO CREEP INTO THE UPPER 30S TO LOWER 40S. COOLER AIR
BEHIND WEDNESDAYS SYSTEM WILL FILTER IN FOR THU...DROPPING HIGHS
INTO 30S. THE SEE-SAW TEMPERATURES WILL CONTINUE...AS A WARMER AIR
WORKS BACK IN FOR FRIDAY AND SATURDAY. HIGHS FRIDAY WILL BE IN THE
UPPER 30S TO LOWER 40S...WITH 40S FOR HIGHS ON SATURDAY.
TEMPERATURES WILL TAKE ANOTHER DOWN TURN ON SUNDAY AS HIGHS WILL
RANGE FROM THE MID 30S IN THE N TO MID 40S IN NRN KY.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
RAIN WILL COME TO AN END AT ALL TERMINALS IN THE NEXT HOUR OR TWO.
IFR/MVFR CEILINGS WILL REMAIN WITH GUSTY NORTHWEST WINDS. EXPECT
CEILINGS TO LIFT A BIT BEFORE SCATTERING OUT. THIS SHOULD OCCUR
BEFORE 12Z. ALTHOUGH THERE REMAINS UNCERTAINTY WITH THE
POSSIBILITY OF ENOUGH LINGERING LOW LEVEL MOISTURE FOR CEILINGS TO
REMAIN WELL INTO THE MORNING. WINDS WILL DECREASE THROUGH THE
NIGHT. ONCE LOWER CLOUDS BREAK EXPECT VFR CONDITIONS THROUGH THE
REST OF THE TAF PERIOD WITH ONLY MID CLOUDS SPREADING BACK IN
LATE.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1037 AM MST SAT JAN 12 2013
.AVIATION...18Z TAFS
AREAS OF -SN AND BLSN WILL CONTINUE TO BRING AREAS OF IFR VSBY INTO
THE AFTERNOON HOURS...THOUGH IMPROVING THROUGH THE DAY. VFR
CONDITIONS ARE EXPECTED AREAWIDE TONIGHT INTO SUNDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 744 AM MST SAT JAN 12 2013/
UPDATE...ARCTIC AIRMASS IN PLACE ACROSS THE REGION...WITH A DEEP
NEAR SATURATED ISOTHERMAL OVERHEAD PER THE 12Z RAP SOUNDING.
FORECAST MODELS CONTINUE TO PROG LINGERING LARGE SCALE LIFT OVER
THE FA THROUGH THE DAY IN Q-VECTOR ANALYSIS. GIVEN THE DEEP NEAR
SATURATED PROFILES EXPECTED TO REMAIN IN PLACE THROUGH EARLY TO
MID AFTERNOON...HAVE UPDATED THE FORECAST TO MENTION LIGHT SNOW
LIKELY IN THE MORNING...TRENDING TO CHANCE IN THE AFTERNOON FOR
MOST OF THE FA. GIVEN COLD PROFILES OUTSIDE THE DGZ...SMALL CRYSTAL
PRODUCTION FAVORED...SUGGESTING COLUMNS/SMALL PLATES OR VERY LIGHT
SNOWFALL. ALL ELSE IN GOOD SHAPE.
PREV DISCUSSION... /ISSUED 327 AM MST SAT JAN 12 2013/
DISCUSSION...WATER VAPOR SHOWS ELONGATED TROF EXTENDING FROM THE
CA BAJA THROUGH THE NRN PLAINS. AT THE SURFACE...TIGHT PRES GRADS
CONTINUE TO PRODUCE GUSTY NW WINDS ACRS THE CWFA. MAIN LOW CENTER
HAS SHIFTED INTO THE UPPER MIDWEST...ALTHOUGH DEFORMATION ZONE
ACROSS WRN SD CONTINUES TO PRODUCE LIGHT SNOW ACROSS OUR AREA.
WIND CHILLS HAVE DROPPED TO 15 BELOW TO 30 BELOW ZERO.
TODAY...WEAK LIFT WILL CONTINUE TO PRODUCE SOME LIGHT SNOW ACROSS
THE CWFA THIS MORNING ALTHOUGH ANY ADDITIONAL ACCUMULATIONS WILL
REMAIN LESS THAN AN INCH. HOWEVER...WINDS GUSTING TO AROUND 40 MPH
WILL CONTINUE TO PRODUCE AREAS OF BLOWING SNOW ESPECIALLY ON THE
SD PLAINS THIS MORNING...ALONG WITH WIND CHILLS TO 30 BELOW. HAVE
DOWNGRADED THE WINTER STORM WARNING OVER PORTIONS OF WRN SD GIVEN
THE DIMINISHING SNOW...AND WILL CARRY WINTER WX ADVISORIES FOR THE
ENTIRE CWFA THROUGH THE MORNING GIVEN COMBINATION OF BLOWING SNOW
AND WIND CHILLS. CONDITIONS WILL IMPROVE THIS AFTERNOON AS WINDS
RELAX.
TONIGHT THROUGH MONDAY NIGHT...UPPER TROF AXIS WILL SHIFT ONLY
SLIGHTLY EWD INTO EARLY NEXT WEEK...WITH SURFACE RIDGE DOMINATE
OVER THE NRN PLAINS. THIS WILL LEAD TO ONLY A SLOW RISE IN
TEMPS...WITH SNOW COVERED AREAS REMAINING SEVERAL DEGREES BELOW
GUIDANCE. GENERALLY DRY CONDITIONS EXPECTED...ALTHOUGH A FEW SNOW
SHOWERS POSSIBLE IN THE NRN BLKHLS SUNDAY AS A WEAK SHORT WAVE
CROSSES THE REGION.
EXTENDED...WARM FRONT PUSHES OVER THE REGION TUESDAY...WITH BROAD
AREA OF ISENTROPIC LIFT DEVELOPING MAINLY OVER THE WRN CWA.
THEREFORE...WILL KEEP PRECIP CHANCES OVER THIS AREA THRU THE DAY
WITH CHANCES DIMINISHING OVERNIGHT. SOME PRECIP OVERNIGHT MAY BE
FREEZING RAIN AS WARM AIR ALOFT CONTINUES TO SLIDE IN...SO WILL HAVE
TO KEEP AN EYE ON THIS. FOR THE REMAINDER OF THE WEEK...
WEST/NORTHWEST FLOW ALOFT SETS UP OVER THE AREA BRINGING NEAR
TO SLIGHTLY ABOVE AVERAGE TEMPERATURES AND DRY CONDITIONS.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...WFO UNR
LONG TERM....WFO UNR
AVIATION...13
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
744 AM MST SAT JAN 12 2013
.UPDATE...ARCTIC AIRMASS IN PLACE ACROSS THE REGION...WITH A DEEP
NEAR SATURATED ISOTHERMAL OVERHEAD PER THE 12Z RAP SOUNDING.
FORECAST MODELS CONTINUE TO PROG LINGERING LARGE SCALE LIFT OVER
THE FA THROUGH THE DAY IN Q-VECTOR ANALYSIS. GIVEN THE DEEP NEAR
SATURATED PROFILES EXPECTED TO REMAIN IN PLACE THROUGH EARLY TO
MID AFTERNOON...HAVE UPDATED THE FORECAST TO MENTION LIGHT SNOW
LIKELY IN THE MORNING...TRENDING TO CHANCE IN THE AFTERNOON FOR
MOST OF THE FA. GIVEN COLD PROFILES OUTSIDE THE DGZ...SMALL CRYSTAL
PRODUCTION FAVORED...SUGGESTING COLUMNS/SMALL PLATES OR VERY LIGHT
SNOWFALL. ALL ELSE IN GOOD SHAPE.
&&
.AVIATION...12Z TAFS
AREAS OF -SN AND BLSN WILL CONT TO BRING AREAS OF IFR VIS THRU EARLY
THIS MORN. CONDITIONS WILL IMPROVE THRU THE DAY AS WINDS/SNOW
DIMINISH WITH MOST LOCATIONS EXPECTED TO BE VFR BY SUNSET.
&&
.PREV DISCUSSION... /ISSUED 327 AM MST SAT JAN 12 2013/
DISCUSSION...WATER VAPOR SHOWS ELONGATED TROF EXTENDING FROM THE
CA BAJA THROUGH THE NRN PLAINS. AT THE SURFACE...TIGHT PRES GRADS
CONTINUE TO PRODUCE GUSTY NW WINDS ACRS THE CWFA. MAIN LOW CENTER
HAS SHIFTED INTO THE UPPER MIDWEST...ALTHOUGH DEFORMATION ZONE
ACROSS WRN SD CONTINUES TO PRODUCE LIGHT SNOW ACROSS OUR AREA.
WIND CHILLS HAVE DROPPED TO 15 BELOW TO 30 BELOW ZERO.
TODAY...WEAK LIFT WILL CONTINUE TO PRODUCE SOME LIGHT SNOW ACROSS
THE CWFA THIS MORNING ALTHOUGH ANY ADDITIONAL ACCUMULATIONS WILL
REMAIN LESS THAN AN INCH. HOWEVER...WINDS GUSTING TO AROUND 40 MPH
WILL CONTINUE TO PRODUCE AREAS OF BLOWING SNOW ESPECIALLY ON THE
SD PLAINS THIS MORNING...ALONG WITH WIND CHILLS TO 30 BELOW. HAVE
DOWNGRADED THE WINTER STORM WARNING OVER PORTIONS OF WRN SD GIVEN
THE DIMINISHING SNOW...AND WILL CARRY WINTER WX ADVISORIES FOR THE
ENTIRE CWFA THROUGH THE MORNING GIVEN COMBINATION OF BLOWING SNOW
AND WIND CHILLS. CONDITIONS WILL IMPROVE THIS AFTERNOON AS WINDS
RELAX.
TONIGHT THROUGH MONDAY NIGHT...UPPER TROF AXIS WILL SHIFT ONLY
SLIGHTLY EWD INTO EARLY NEXT WEEK...WITH SURFACE RIDGE DOMINATE
OVER THE NRN PLAINS. THIS WILL LEAD TO ONLY A SLOW RISE IN
TEMPS...WITH SNOW COVERED AREAS REMAINING SEVERAL DEGREES BELOW
GUIDANCE. GENERALLY DRY CONDITIONS EXPECTED...ALTHOUGH A FEW SNOW
SHOWERS POSSIBLE IN THE NRN BLKHLS SUNDAY AS A WEAK SHORT WAVE
CROSSES THE REGION.
EXTENDED...WARM FRONT PUSHES OVER THE REGION TUESDAY...WITH BROAD
AREA OF ISENTROPIC LIFT DEVELOPING MAINLY OVER THE WRN CWA.
THEREFORE...WILL KEEP PRECIP CHANCES OVER THIS AREA THRU THE DAY
WITH CHANCES DIMINISHING OVERNIGHT. SOME PRECIP OVERNIGHT MAY BE
FREEZING RAIN AS WARM AIR ALOFT CONTINUES TO SLIDE IN...SO WILL HAVE
TO KEEP AN EYE ON THIS. FOR THE REMAINDER OF THE WEEK...
WEST/NORTHWEST FLOW ALOFT SETS UP OVER THE AREA BRINGING NEAR
TO SLIGHTLY ABOVE AVERAGE TEMPERATURES AND DRY CONDITIONS.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 11 AM MST /NOON CST/ THIS MORNING
FOR BENNETT-BUTTE-CENTRAL BLACK HILLS-CUSTER CO PLAINS-FALL
RIVER-HAAKON-HARDING-HERMOSA FOOT HILLS-JACKSON-MELLETTE-
NORTHERN BLACK HILLS-NORTHERN FOOT HILLS-NORTHERN MEADE CO
PLAINS-PENNINGTON CO PLAINS-PERKINS-RAPID CITY-SHANNON-
SOUTHERN BLACK HILLS-SOUTHERN FOOT HILLS-SOUTHERN MEADE CO
PLAINS-STURGIS/PIEDMONT FOOT HILLS-TODD-TRIPP-ZIEBACH.
WY...WINTER WEATHER ADVISORY UNTIL 11 AM MST THIS MORNING FOR
NORTHEASTERN CROOK-NORTHERN CAMPBELL-SOUTHERN CAMPBELL-
WESTERN CROOK-WESTON-WYOMING BLACK HILLS.
&&
$$
SHORT TERM...JOHNSON
EXTENDED...77
AVIATION...77
UPDATE...JC
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
240 PM CST SAT JAN 12 2013
.SHORT TERM...TONIGHT THROUGH TUESDAY
240 PM CST SAT JAN 12 2013
THE MAIN FOCUS IN THE SHORT TERM IS WITH THE SNOW POTENTIAL
TONIGHT ACROSS FAR SOUTHWEST WISCONSIN AND NORTHEAST IOWA ALONG
WITH TEMPERATURES INTO EARLY NEXT WEEK.
CURRENTLY...AN UPPER LEVEL TROUGH IS DIGGING SOUTH ACROSS THE
PLAINS WHILE A RIDGE OF HIGH PRESSURE BECOMES MORE AMPLIFIED
ACROSS THE EAST COAST. AT THE SURFACE...COLDER AIR IS DROPPING
DOWN FROM CENTRAL CANADA DOWN THROUGH THE PLAINS ON THE BACK SIDE
OF A LOW THAT IS MOVING INTO WESTERN QUEBEC. AN INVERTED TROUGH
EXTENDS TO THE SOUTHWEST OUT OF THIS LOW AND HAS HELPED TO POOL
SOME HIGHER LOW LEVEL HUMIDITY THAT HAPPENS TO BE IN THE -8C TO
-12C RANGE...WHICH INTRODUCES ICE INTO THE CLOUD LAYER. OVERALL
FORCING IS WEAK BUT ENOUGH FROM THE SURFACE TROUGH TO PRODUCE SNOW
SHOWERS AND FLURRIES ACROSS THE REGION.
12.12Z NAM/GFS AND 12.18Z RAP SOUNDINGS SHOW THE THIN LOW LEVEL
CLOUD LAYER STICKING AROUND OVERNIGHT INTO TOMORROW AND DEEPENING
AS A LOW PRESSURE SYSTEM TRACKS TO THE NORTHEAST FROM THE SOUTHERN
PLAINS ON INTO MICHIGAN TONIGHT. THE QUESTION WITH THIS SYSTEM HAS
BEEN HOW FAR WEST THE SNOW WOULD MAKE IT. THE PREVIOUS RUNS OF THE
ECMWF HAD BEEN THE FURTHEST WEST OVER THE PAST FEW DAYS...BUT NOW
HAS COME INTO A CONSENSUS WITH WHAT THE 12.12Z NAM/GFS/GEM ARE
SHOWING WITH THE TRACK FURTHER TO THE EAST WITH JUST A BRIEF
PERIOD OF LIGHT SNOW OCCURRING ACROSS NORTHEAST IOWA AND FAR
SOUTHWEST WISCONSIN. 12.12Z NAM/GFS AND 12.18Z RAP CROSS SECTIONS
SHOWS AN ASCENDING BAND OF FRONTOGENESIS THAT IS CLOSER TO THE
SURFACE TO THE SOUTHEAST AND MORE OF A MID LEVEL CIRCULATION
ACROSS THE REST OF THE FORECAST AREA. THIS FORCING SHOULD BE
ENOUGH TO AT LEAST PRODUCE SOME FLURRIES...BUT CAN NOT COMPLETELY
RULE OUT THAT SOME SNOW COULD MAKE IT FURTHER WEST DEPENDING ON
HOW STRONG THE CIRCULATION GETS. THE SNOW WILL DEVELOP NORTHWARD
THIS EVENING BEFORE QUICKLY GETTING SHUNTED OFF TO THE EAST BY DAY
BREAK. ACCUMULATIONS ARE EXPECTED TO BE ON THE LIGHT SIDE AT LESS
THAN AN INCH ACROSS GRANT COUNTY.
AFTER THIS SYSTEM MOVES THROUGH...THE COLD AIR WILL MOVE IN ACROSS
THE REGION FROM THE NORTHWEST AND LINGER INTO THE EARLY PART OF
NEXT WEEK. HOW FAR TEMPERATURES ARE ABLE TO DROP IS OF QUESTION
RIGHT NOW SINCE MOST OF THE AREAS SNOW PACK HAS ERODED DUE TO THE
FOG...WIND...RAIN AND WARM AIR THAT WAS AROUND EARLIER THIS WEEK.
HAVE NOT MADE MANY ADJUSTMENTS TO THE GOING FORECAST WITH SUNDAY
LOOKING LIKE THE COLDEST DAY OVER THE NEXT WEEK.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
240 PM CST SAT JAN 12 2013
THE NEXT CHANCE FOR SNOW COMES IN TUESDAY NIGHT INTO WEDNESDAY AS
A MID LEVEL SHORT WAVE TROUGH DIVES DOWN FROM NORTHWEST CANADA
DOWN INTO THE UPPER MISSISSIPPI RIVER VALLEY. THERE ARE SOME
DIFFERENCES BETWEEN THE LONG TERM GUIDANCE WITH THIS SYSTEM WITH
THE 12.12Z GFS SHOWING A MUCH MORE COMPACT TROUGH THAT COMES
THROUGH FASTER THAN WHAT THE 12.12Z ECMWF IS ADVERTISING. THIS
LEADS TO A DEEPER SURFACE LOW THAT DIVES FURTHER SOUTH ON THE GFS
COMPARED TO THE ECMWF AS WELL. BECAUSE OF THESE DIFFERENCES...HAVE
NOT HIT THE PRECIPITATION CHANCES TO HIGH YET...BUT OVERALL THE
BETTER CHANCES FOR SEEING THE SNOW WILL BE ACROSS THE NORTHERN
PORTION OF THE FORECAST AREA. WITH THERE NOT BEING MUCH OF A SHIFT
IN THE UPPER LEVEL PATTERN...THERE COULD BE A FEW MORE CHANCES OF
LIGHT SNOW NEXT WEEK BUT MUCH OF THE FORCING APPEARS TO BE GOING
JUST NORTH OF THE REGION. WITH THE PATTERN NOT SHIFTING
MUCH...TEMPERATURES WILL NOT VARY MUCH EITHER AND REMAIN FAIRLY
SEASONAL.
&&
.AVIATION...THROUGH 18Z SUNDAY
1142 AM CST SAT JAN 12 2013
DEEP LOW PRESSURE WILL WEAKEN AND CONTINUE MOVING FARTHER EAST
INTO ONTARIO. WITH LINGERING CYCLONIC FLOW AND COLD AIR ADVECTION
ACROSS THE AREA...PLAN ON MVFR CLOUDS ALONG WITH SCATTERED FLURRY
ACTIVITY TO CONTINUE INTO THIS EVENING. EXPECTING WINDS TO SUBSIDE
THROUGH THE DAY AS PRESSURE GRADIENT BECOMES MORE RELAXED.
ANOTHER WEAKER WAVE OF LOW PRESSURE WILL THEN RIPPLE NORTHEAST
FROM THE SOUTHERN PLAINS INTO THE GREAT LAKES REGION TONIGHT
THROUGH SUNDAY MORNING. WITH THIS TRACK...EXPECTING ANY
ACCUMULATING SNOW TO REMAIN SOUTH OF THE AREA. BUFKIT SOUNDING
DATA CONTINUES TO SHOW MVFR CLOUD COVER AND FLURRIES LINGERING THROUGH
18Z SUNDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
240 PM CST SAT JAN 12 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
424 AM EST MON JAN 14 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE REGION THIS MORNING AND THEN
BECOME STATIONARY TO OUR SOUTH TONIGHT THROUGH WEDNESDAY AS A
SERIES OF WEAK WAVES OF LOW PRESSURE RIDE ALONG IT. A COLD FRONT
CROSSES THE TRI-STATE ON THURSDAY WITH CANADIAN HIGH PRESSURE
BUILDING IN FOR THURSDAY NIGHT THROUGH SATURDAY. ANOTHER COLD FRONT
MOVES ACROSS THE TRI-STATE ON SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD FRONT APPROACHING CENTRAL PA AS OF 08Z WITH TEXTBOOK WIND
SHIFT AND TEMP FALLS. AREA OF LIGHT RAIN OVER EASTERN PA RIDING
NORTH WILL PROVIDE MEASURABLE PCPN FOR NORTHWEST ZONES THROUGH
11Z BEFORE WEAKENING. 05Z HRRR RUN DEPICTS FRONT NICELY IN ITS
REFLECTIVITY FIELDS...THOUGH DO NOT EXPECT THIS TO PRODUCE MUCH
MORE THAN SPRINKLES. IN FACT...ONLY CHANCE POPS FOR MEASURABLE
PCPN AFTER 11Z OVER THE WESTERN TWO THIRDS OF THE REGION WITH
THE MAIN PCPN BEING SPOTTY LIGHT DRIZZLE/SPRINKLES. FRONT CLEARS
MONTAUK BY 18Z WITH FOG/DRIZZLE ALL ENDED BY NOON.
AS FOR FOG ADVISORY...HAVE SPLIT THAT UP FOR TIMING. I WAS GOING
THE CITY AND LONG ISLAND...BUT BASED ON LATEST LAMP GUIDANCE...HAVE
KEPT IT.
HAVE UNDER CUT MOS NUMBERS BASED PRIMARILY BASED ON 15 DEGREE DROP
SEEN ON WITH THE FROPA IN WESTERN PA AND EASTERN OH. DESPITE
THIS...STILL THINK WE CAN REACH THE LOWER 50S WITH DOWNSLOPE AND NORTHERLY
FLOW...THOUGH CONFIDENCE IS LOW AND WOULD NOT BE SHOCKED WITH A
BUST AND TEMPS STAYING IN THE 40S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
UNCERTAINTY CONTINUES TONIGHT AS MOISTURE SPREADS NORTHEAST ALONG
THE STALLED FRONT. OUR REGION IS ON THE NORTHERN EDGE OF THE PCPN
WITH THIS FEATURE. 00Z NAM AND WRF ARW SUPPORT A DRY SOLUTION
WITH GEM/GFS/WRF-ARW/AND MANY SREF MEMBERS SUPPORTING LGT PCPN
FOR THE SOUTHERN THIRD OF THE FCST AREA.
THERE IS AN IMPRESSIVE 170+KT SUBTROPICAL JET STREAK COMING OUT OF
TX WHICH PLACES THE REGION IN THE RIGHT FRONT QUADRANT THAT WOULD
HELP BUILD THE SFC HIGH AND AND BRING IN DRIER AIR. BUT THE NWP
QPF GUIDANCE CAN NOT BE IGNORED. HAVE THUS GONE WITH A TIGHT
GRADIENT OF POPS AND USED LIKELY FOR THE SOUTHERN PARTS OF THE
CITY AND LONG ISLAND.
THERMAL PROFILES SUPPORT SOME MIXING OF SLEET TO THE NORTH OF THE
CITY AND LONG ISLAND...BUT IMPACT IS EXPECTED TO BE MINIMAL IF THE
SLEET OCCURS AT ALL.
TONUGHT`S LOW TEMPS WERE A BLEND OF NAM AND GFS MOS WITH
ADJUSTMENTS UP DUE TO EXPECTED EXTENSIVE CLOUD COVER.
WEAK HIGH PRESSURE BUILDS IN BRIEFLY FOR TUESDAY. TEMPS WERE AGAIN
A BLEND OF MOS - NO ADJUSTMENTS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
INCREASING CONSENSUS AMONG THE MODELS THAT THE REGION WILL
EXPERIENCE LIGHT TO MODERATE PRECIPITATION TUESDAY NIGHT INTO
WEDNESDAY AS A WAVE OF LOW PRESSURE PASSES TO OUR SOUTH ALONG A
STALLED FRONTAL BOUNDARY. HAVE CHANCE POPS N AND LIKELY POPS S IN
THIS TIME FRAME. FOR NOW...BASED ON A BLEND OF NAM/GFS/ECMWF LOW
LEVEL THERMAL PROFILES - APPEARS WILL BE A MIX OF RAIN/SNOW/SLEET
ACROSS NYC/LONG ISLAND/MOST OF NE NJ CHANGING TO ALL RAIN WEDNESDAY
MORNING...AND A MIX OF SNOW/SLEET CHANGING TO ALL RAIN BEFORE ENDING
WEDNESDAY AFTERNOON. FOR NOW THINKING SUB-ADVISORY AMOUNTS ARE MOST
LIKELY...BUT THERE IS SOME POTENTIAL FOR ADVISORY LEVEL ACCUMULATION
ACROSS NORTHERN INTERIOR ZONES. WILL CONTINUE TO MONITOR.
USED A BLEND OF NAM/GFS MOS AND 2-METER TEMPERATURES FOR LOWS
TUESDAY NIGHT AND HIGHS WEDNESDAY...WITH LOWS BETWEEN...5 AND 10
DEGREES ABOVE NORMAL AND HIGHS A FEW DEGREES ABOVE NORMAL.
THE REGION WILL BE AT THE BASE OF A 500 HPA TROUGH ANCHORED WITH THE
POLAR VORTEX OVER HUDSON BAY WEDNESDAY NIGHT-THURSDAY NIGHT. THE
BASE OF THE TROUGH LIFTS FRIDAY WITH ZONAL FLOW GIVING WAY TO SW
FLOW/SLIGHT RIDGING ALOFT BY LATE SATURDAY. THE GFS IS FASTER THAN
THE ECMWF IN BRINGING IN THE NEXT RE-ENFORCING SHOT OF COLD AIR -
SATURDAY NIGHT VICE DURING THE DAY ON SUNDAY. HOWEVER...WITHOUT ANY
CLEAR INDICATION OF ONE MODEL BEING MORE RIGHT THAN THE OTHER...HAVE
OPTED FOR A GFS/ECMWF BLEND IN THIS TIME FRAME.
OTHER THAN POSSIBLY SOME FLURRIES UNDER THE COLD POOL
THURSDAY/THURSDAY NIGHT - NOT CONFIDENT ENOUGH IN THIS TO REFLECT IN
THE FORECAST AT THIS TIME...AND A SLIGHT CHANCE OF SNOW SHOWERS WITH
THE ARRIVAL OF THE COLD AIR SUNDAY OVER FAR W ZONES...IT APPEARS LOW
LEVELS WILL BE TOO DRY TO SUPPORT ANY PRECIPITATION WEDNESDAY
NIGHT-SUNDAY.
FOR TEMPERATURES WEDNESDAY NIGHT-SUNDAY USED A BLEND OF MEX/MEX
ENSEMBLE MEAN/ECE/HPC GUIDANCE. TEMPERATURES TREND FROM 5-10 DEGREES
ABOVE NORMAL AT THE START OF THIS TIME FRAME TO SLIGHTLY BELOW
NORMAL ON FRIDAY...THEN REBOUND TO A TAD ABOVE NORMAL FOR THE
WEEKEND. DEPENDING ON EXACTLY WHEN THE COLD AIR MOVES IN
SUNDAY...COULD END UP BEING BELOW NORMAL THEN...BUT TOO MUCH
UNCERTAINTY TO FORECAST THAT AT THIS TIME.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
A COLD FRONT APPROACHES EARLY THIS MORNING...AND PASSES THROUGH AFTER
DAYBREAK. HIGH PRESSURE GRADUALLY BUILDS INTO THE REGION FROM THE
WEST THROUGH TONIGHT.
ABUNDANT LOW-LEVEL MOISTURE AND LIGHT WINDS AHEAD OF AN APPROACHING
COLD FRONT HAVE RESULTED WIDESPREAD LIFR OR LOWER CONDITIONS IN
STRATUS/FOG/DZ. MODERATE TO HIGH CONFIDENCE IN THIS CONTINUING TILL
DAYBREAK...HOWEVER THERE MAY BE BRIEF PERIODS OF CHANGING CONDITIONS.
CONDITIONS EXPECTED TO IMPROVE A BIT TOWARDS DAYBREAK...PARTICULARLY
ACROSS THE NYC/NJ METRO TERMINALS WHERE SW WINDS AT 1-2 KFT INCREASE
TO 30-40 KT. THIS MIGHT PROMOTE ENOUGH TURBULENT MIXING TO SLIGHTLY
IMPROVED VSBY/CIGS TO IFR. IN ADDITION...THERE COULD BE SOME
MARGINAL LOW LEVEL WIND SHEAR ISSUES.
COLD FRONT WILL PUSH ACROSS THE REGION JUST AFTER DAYBREAK...WITH
CONDITIONS SLOWLY IMPROVING AT FIRST...THEN VSBY QUICKLY BECOMING
VFR AROUND 15Z-16Z. TIMING OF LIFR/IFR CIGS IMPROVEMENT COULD BE OFF
BY AN HOUR OR SO DEPENDING ON STRENGTH OF DRY AIR ADVECTION BEHIND
THE FRONT.
HIGH CONFIDENCE IN VFR BY THIS AFTERNOON. NW WINDS 10-15G20KT
EXPECTED...MAINLY RIGHT OF 310 MAGNETIC.
WINDS GRADUALLY WEAKEN THIS EVENING AND VEER N. A WEAK WAVE RIDING
TO THE SOUTH WILL LIKELY RESULT IN INCREASING HIGH/MID CLOUDS THIS
EVENING...WITH A FEW SHOWERS POSSIBLE AFTER MIDNIGHT ACROSS
SOUTHERN TERMINALS.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: AMENDMENTS EXPECTED THIS MORNING FOR CHANGING
FLIGHT CATEGORIES - VARIABLE CIGS AND VSBYS.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: AMENDMENTS EXPECTED THIS MORNING FOR CHANGING
FLIGHT CATEGORIES - VARIABLE CIGS AND VSBYS.
KLGA FCSTER COMMENTS: AMENDMENTS EXPECTED THIS MORNING FOR CHANGING
FLIGHT CATEGORIES - VARIABLE CIGS AND VSBYS.
KTEB FCSTER COMMENTS: AMENDMENTS EXPECTED THIS MORNING FOR CHANGING
FLIGHT CATEGORIES - VARIABLE CIGS AND VSBYS.
KHPN FCSTER COMMENTS: MEDIUM TO HIGH CONFIDENCE OF LIFR OR LESS
UNTIL 13Z...THEN GRADUAL IMPROVEMENT EXPECTED.
KISP FCSTER COMMENTS: MEDIUM TO HIGH CONFIDENCE OF LIFR OR LESS
UNTIL 13Z...THEN GRADUAL IMPROVEMENT EXPECTED.
.OUTLOOK FOR 06Z TUE THROUGH FRI...
.LATE TONIGHT-TUE MORNING...LOW PROB FOR MVFR CONDS...ESPECIALLY
LATE TONIGHT FOR NYC METRO AND LONG ISLAND...AS WEAK LOW PRESSURE
PASSES TO THE SOUTH. PCPN TYPE SHOULD BE MOSTLY RAIN...BUT SOME
SNOW COULD MIX IN.
.TUE AFTERNOON/EVENING...VFR.
.LATE TUE NIGHT-WED MORNING...SLIGHT CHANCE FOR MVFR CONDS FOR NYC
METRO AND LONG ISLAND...AS ANOTHER WEAK LOW PASSES TO THE SOUTH.
.WED AFTERNOON-FRI...VFR. COLD FROPA THU EVENING...FOLLOWED BY
GUSTY NW WINDS THU NIGHT-FRI.
&&
.MARINE...
THE DENSE FOG ADVISORY REMAINS UP THROUGH THE MORNING.
COLD FRONT PASSES MID TO LATE MORNING AND WHILE THERE MAY BE A
GUST TO THE MID 20S...THIS WOULD ONLY BE WITH THE FRONT ITSELF.
SEAS IN A SE SWELL ARE AROUND 4 FEET ON THE OCEAN AT MOST...THUS
THE SMALL CRAFT ADVISORY FOR THE OCEAN HAS BEEN DROPPED.
A LIGHT PRESSURE GRADIENT ACROSS THE REGION WILL PROMOTE WINDS 10 KT
OR LESS TUESDAY INTO WEDNESDAY. STRONG COLD ADVECTION WILL SEE
SMALL CRAFT CONDITIONS AND POSSIBLY GALE FORCE GUSTS ON ALL WATERS
WEDNESDAY NIGHT AND POSSIBLY INTO THURSDAY. SUB-SMALL CRAFT
CONDITIONS SHOULD RETURN TO ALL WATERS BY FRIDAY.
&&
.HYDROLOGY...
LIGHT PCPN IS EXPECT THIS MORNING AND AGAIN OVERNIGHT. A 1/4 OF
AN INCH OF LIQUID EQUIVALENT...AND POSSIBLY A BIT MORE OVER LONG
ISLAND AND NYC...IS EXPECTED OVER THE REGION TUESDAY NIGHT AND
WEDNESDAY.
NO HYDROLOGIC IMPACTS ARE EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR CTZ006>008-
010>012.
DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR CTZ005-009.
NY...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR NYZ078>081-
177-179.
DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR NYZ067>075-
176-178.
NJ...DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR NJZ002-004-
006-103>108.
MARINE...DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR ANZ330-335-338-340-
345-350-353-355.
&&
$$
SYNOPSIS...TONGUE
NEAR TERM...TONGUE
SHORT TERM...TONGUE
LONG TERM...MALOIT
AVIATION...BC/NV
MARINE...MALOIT/TONGUE
HYDROLOGY...TONGUE
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1259 AM EST MON JAN 14 2013
.SYNOPSIS...
A COLD FRONT OVER WESTERN PENNSYLVANIA APPROACHES OVERNIGHT. THE
FRONT MOVES SOUTH AND EAST BY AFTERNOON AND THEN BECOMES
STATIONARY TO OUR SOUTH TONIGHT THROUGH WEDNESDAY WITH A SERIES
OF WEAK WAVES OF LOW PRESSURE RIDING ALONG IT. HIGH PRESSURE
RETURNS ON THURSDAY...FOLLOWED BY A COLD FRONT PASSING THROUGH
THURSDAY NIGHT. HIGH PRESSURE THEN REMAINS IN CONTROL INTO THE END
OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
FRONT IS NEARING KPIT AS OF 0530Z AND IS ACCELERATING WITH G30
KT IN IT`S WAKE. THUS ARRIVAL IN THE WESTERN THIRD OF THE CWA BY
SUNRISE SEEMS LIKELY. WILL CONTINUE THE DENSE FOG ADVISORY AND
HAVE MADE THE DRIZZLE PERSISTENT. VSBYS ARE FLUCTUATING UP TO 3
MILES AT KEWR...BUT WILL NOT TRY TO CHASE THINGS WITH MOS STILL
SUGGESTING LOWERING TOWARDS SUNRISE.
PCPN WITH THE FRONT DIMINISHES AS IT APPROACHES PER ALL LATEST
NWP. HRRR DOES HAVE BAND OF LIGHT PCPN MAKING TO THE CT/LONG
ISLAND AREAS...BUT BELIEVE THIS IS OVER DONE. DRIZZLE IS THE MAIN
PCPN PRODUCER.
WARM ADVECTION ALOFT WILL CONTINUE TO SUPPORT DRIZZLE AND FOG
UNTIL THE FRONT DOES PASS WITH STEADY TEMPS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
COLD FRONT PUSHES DRIZZLE...FOG AND ANY LIGHT RAIN OUT OF THE
REGION BY NOON FROM NORTHWEST TO SOUTHEAST. CLEARING BY MIDDAY. A
GUSTY NW FLOW ON THE BACKSIDE THIS AFTN.
HIGHS WILL GET UP TO AROUND 50 INLAND...AND THE LOW TO MID 50S AT
THE COAST. THE STRONGEST COLD ADVECTION FOLLOWS IN THE AFT/EVE...
WHICH ALLOWS THE AIR MASS TO WARM UP WELL ABOVE SEASONABLE LEVELS.
GUSTS IN THE AFT WILL BE UP TO 20 MPH.
A WEAK WAVE OF LOW PRESSURE PASSES WELL SOUTH AND EAST LATE MON
NIGHT WITH SOME LIGHT PCPN...MAINLY NEAR THE COAST...BUT HAVE
PUSHED BACK THE TIMING TO AFT 9 PM. AS THE COLD AIR FILTERS
IN...ANY PCPN THAT DOES FALL MAY MIX WITH SOME SLEET OR SNOW. NO
ACCUM IS EXPECTED. THERE COULD HOWEVER BE A FEW SLICKS SPOTS FOR
THE MORNING COMMUTE TUE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MOISTURE SHIFTS TO THE SOUTH THROUGH TUESDAY. THIS IS IN ASSOCIATION
WITH A STALLING FRONTAL BOUNDARY TO OUR SOUTH. THEREFORE...ONLY A
SLIGHT CHANCE OF PCPN OVER THE LAND AREAS DURING THE
MORNING...THEN DRY IN THE AFTERNOON. AS FOR PCPN TYPE...BY
DAYBREAK ON TUESDAY...A WARM NOSE ALOFT ERODES AND WOULD LIKELY
SUPPORT EITHER SNOW...SLEET OR A MIXTURE OF THE TWO. THEN BY LATE
MORNING...THE BOUNDARY LAYER WOULD WARM UP ENOUGH FOR RAIN BEING
MIXED WITH THE WINTRY PCPN. IN ANY CASE...POPS AND QPF ARE LOW.
HIGH TEMPERATURES STILL END UP A LITTLE ABOVE NORMAL.
A WAVE OF LOW PRESSURE THEN MOVES ALONG THE FRONTAL BOUNDARY TUESDAY
NIGHT INTO WEDNESDAY...BUT AGAIN...ONLY A LOW CHANCE OF PCPN...AND
FOCUSED LATE AT NIGHT INTO WEDNESDAY MORNING. SNOW WOULD BE THE MOST
LIKELY PCPN TYPE UNTIL MID-MORNING...THEN EVENTUALLY A CHANGE TO
RAIN BY THE AFTERNOON IF THERE`S ANY LINGERING PCPN.
FOR THURSDAY...A COLD FRONT PASSES THROUGH IN THE EVENING. MAYBE A
SPRINKLE IN THE AFTERNOON...THEN A SPRINKLE OR FLURRY IN THE
EVENING. HIGH PRESSURE OTHERWISE REMAINS THE DOMINANT FEATURE FOR
OUR WEATHER THROUGH THE UPCOMING WEEKEND. A COLD FRONT COULD BRING
PCPN OUR WAY ON SUNDAY...BUT WILL GO WITH A DRY FORECAST FOR NOW
AS MOISTURE APPEARS TO BE LACKING.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
A COLD FRONT APPROACHES EARLY THIS MORNING...AND PASSES THROUGH AFTER
DAYBREAK. HIGH PRESSURE GRADUALLY BUILDS INTO THE REGION FROM THE
WEST THROUGH TONIGHT.
ABUNDANT LOW-LEVEL MOISTURE AND LIGHT WINDS AHEAD OF AN APPROACHING
COLD FRONT HAVE RESULTED IN THE RE-DEVELOPMENT OF WIDESPREAD LIFR OR
LOWER CONDS IN STRATUS/FOG/DZ. MODERATE TO HIGH CONFIDENCE IN THIS
CONTINUING TILL DAYBREAK. THERE IS SOME UNCERTAINTY IF THESE CONDS
IMPROVE A BIT TOWARDS DAYBREAK THOUGH...PARTICULARLY NYC/NJ METRO
TERMINALS AS SW WINDS AT 1-2 KFT INCREASE TO 30-40 KT. THIS MIGHT
PROMOTE ENOUGH TURBULENT MIXING TO SLIGHTLY IMPROVED VSBY/CIGS TO
IFR. IN ADDITION...THERE COULD BE SOME MARGINAL LOW LEVEL WIND
SHEAR ISSUES.
COLD FROPA STILL EXPECTED JUST AFTER DAYBREAK...WITH CONDS SLOWLY
IMPROVING AT FIRST...THEN VSBY QUICKLY BECOMING VFR AFTER ABOUT
15Z-16Z. TIMING OF LIFR/IFR CIGS IMPROVEMENT COULD BE OFF BY AN HOUR
OR SO DEPENDING ON STRENGTH OF DRY AIR ADVECTION BEHIND THE FRONT.
HIGH CONFIDENCE IN VFR BY THIS AFTERNOON. NW WINDS
10-15G20KT EXPECTED...MAINLY RIGHT OF 310 MAGNETIC.
WINDS GRADUALLY WEAKEN THIS EVENING AND VEER N. A WEAK WAVE RIDING
TO THE SOUTH WILL LIKELY RESULT IN INCREASING HIGH/MID CLOUDS THIS
EVENING...WITH A FEW SHOWERS POSSIBLE AFTER MIDNIGHT ACROSS
SOUTHERN TERMINALS.
.OUTLOOK FOR 06Z TUE THROUGH FRI...
.LATE TONIGHT-TUE MORNING...LOW PROB FOR MVFR CONDS...ESPECIALLY
LATE TONIGHT FOR NYC METRO AND LONG ISLAND...AS WEAK LOW PRESSURE
PASSES TO THE SOUTH. PCPN TYPE SHOULD BE MOSTLY RAIN...BUT SOME
SNOW COULD MIX IN.
.TUE AFTERNOON/EVENING...VFR.
.LATE TUE NIGHT-WED MORNING...SLIGHT CHANCE FOR MVFR CONDS FOR NYC
METRO AND LONG ISLAND...AS ANOTHER WEAK LOW PASSES TO THE SOUTH.
.WED AFTERNOON-FRI...VFR. COLD FROPA THU EVENING...FOLLOWED BY
GUSTY NW WINDS THU NIGHT-FRI.
&&
.MARINE...
THE DENSE FOG ADVISORY REMAINS UP THROUGH THE NIGHT FOR
VISIBILITIES 1 NM OR LESS.
WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA
THROUGH THE OVERNIGHT.
WINDS PRECEDING A COLD FRONTAL PASSAGE IN THE MORNING WILL PRODUCE
MARGINAL SCA WINDS AND SEAS ACROSS THE OCEAN WATERS EAST OF FIRE
ISLAND INLET. CONFIDENCE IN THIS SCENARIO IS WANING AND IT IS
QUITE POSSIBLE THAT SCA CONDITIONS ARE NOT MET. A GUSTY NW FLOW MON
AFT/ERLY EVE WILL GET UP TO AROUND 20 KT BEFORE DIMINISHING LATE
AS HIGH PRESSURE NOSES IN FROM THE OHIO VALLEY.
RELATIVELY TRANQUIL CONDITIONS PREVAIL ON TUESDAY AND WEDNESDAY.
SCA CONDITIONS THEN BECOME POSSIBLE AGAIN WEDNESDAY NIGHT...AND
MORE LIKELY DURING THURSDAY AS THE PRESSURE GRADIENT TIGHTENS
AHEAD OF A COLD FRONT...CAUSING WINDS AND SEAS TO INCREASE. THE
COLD FRONT MOVES THROUGH THURSDAY NIGHT...WITH SUB SCA CONDITIONS
PROBABLE ACROSS ALL WATERS BY FRIDAY AFTERNOON.
&&
.HYDROLOGY...
THERE IS ONLY POTENTIAL FOR LIGHT PRECIPITATION AMOUNTS THROUGH THE
FORECAST PERIOD.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR CTZ005>012.
NY...DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR NYZ067>075-
078>081-176>179.
NJ...DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR NJZ002-004-
006-103>108.
MARINE...DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR ANZ330-335-
338-340-345-350-353-355.
SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 6 PM EST THIS
EVENING FOR ANZ350-353.
&&
$$
SYNOPSIS...JC/DW
NEAR TERM...JC/TONGUE/DW
SHORT TERM...TONGUE/DW
LONG TERM...JC
AVIATION...NV
MARINE...JC/DW
HYDROLOGY...JC/DW
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
406 AM EST MON JAN 14 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH THE FIRST PART OF
THE WORK WEEK. THIS WILL LEAD TO MAINLY DRY CONDITIONS AND MORE
SEASONABLE TEMPERATURES THROUGH WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH THIS AFTERNOON.
AS IT DOES...NORTH TO NORTHWEST LOW LEVEL FLOW WILL DECREASE BUT
WEAK CAA WILL CONTINUE THROUGH MUCH OF THE DAY. A FAIR AMOUNT OF
LOW CLOUDS ARE STILL IN PLACE ACROSS THE REGION BUT SATELLITE
IMAGES ARE INDICATING SOME BREAKS ACROSS PARTS OF OUR SOUTHWEST.
MAIN QUESTION FOR TODAY WILL BE HOW FAST THESE CLOUDS DISSIPATE.
THE RAP IS HANGING ON TO A FAIR AMOUNT OF LOW LEVEL MOISTURE
THROUGH THIS AFTERNOON. THIS IS PROBABLY OVERDONE AND PREFER
SOMETHING CLOSER TO WHAT THE NAM IS INDICATING ALTHOUGH THE WEAK
CAA MAY HELP KEEP THE CLOUDS AROUND A BIT LONGER. WILL THEREFORE
ALLOW FOR PARTIAL CLEARING HEADING THROUGH LATE MORNING INTO EARLY
AFTERNOON. 500 MB MOISTURE WILL INCREASE FROM THE SOUTHWEST LATER
THIS AFTERNOON AND THIS COULD ALLOW FOR AN INCREASE IN SOME
HIGHER LEVEL CLOUDS LATER TODAY. WITH WEAK CAA...EXPECT HIGHS
RANGING FROM THE UPPER 20S TO LOWER 30S IN THE NORTHWEST TO THE
MID AND UPPER 30S ACROSS THE SOUTHEAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
SURFACE HIGH PRESSURE WILL REMAIN ACROSS THE AREA TUESDAY INTO
WEDNESDAY...PROVIDING MAINLY DRY CONDITIONS. THE ONE EXCEPTION
COULD BE ACROSS OUR FAR SOUTHEAST AS A COUPLE OF SHORT WAVES RIDE
UP ALONG THE APPALACHIANS. THE MODELS HAVE TRENDED A BIT FARTHER
NORTH WITH THEIR NORTHERN PERIPHERY WITH THE INITIAL WAVE TONIGHT
AND THEN THE SECOND ONE FOR TUESDAY NIGHT. BOTH THE 00Z ECMWF AND
GFS ARE TRYING TO BRUSH A FEW OF OUR SOUTHEASTERN COUNTIES WITH
PCPN WHILE THE 00Z AND 06Z NAM ARE KEEPING EVERYTHING TO THE
SOUTH. GIVEN THE TRENDS...WILL GO AHEAD AND INTRODUCE SOME POPS
ACROSS THE FAR SOUTHEAST FOR TONIGHT AND TUESDAY NIGHT...BUT KEEP
THEM LOW AT THIS POINT. FORECAST SOUNDINGS ARE INDICATING THE
POSSIBILITY OF A RAIN/SNOW MIX WITH ANY PCPN BUT GIVEN THAT IT
WOULD BE AT NIGHT...IT MAY BE MORE LIKELY TO BE SNOW THAN RAIN.
CLOUDS WILL BE DEPENDENT ON JUST HOW FAR NORTH THESE WAVES MAKE IT
AND THIS WILL ALSO HAVE AN AFFECT ON LOW TEMPERATURES BOTH TONIGHT
AND TUESDAY NIGHT. WILL GO AHEAD AND ALLOW FOR A DECENT GRADIENT
BOTH NIGHTS FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE BUILDS BACK INTO THE OH AND TN VALLEYS THU INTO
FRI.
ENERGY KEEPS RUNNING THROUGH THE SUBTLE ERN U.S. LONGWAVE TROF OVER
THE WEEKEND. GFS AND ECMWF DIFFER ON THE STRENGTH OF A SYSTEM ON
SATURDAY....BUT BOTH PUSH COOLER AIR IN ON SUNDAY WITH A TRAILING
COLD FRONT. ONCE AGAIN THE MOISTURE IS LOOKING LIMITED FOR
SUNDAY...SO KEPT THE FCST DRY.
COOLER AIR BEHIND WEDNESDAYS SYSTEM WILL FILTER IN FOR
THU...DROPPING HIGHS INTO 30S. THE SEE-SAW TEMPERATURES WILL
CONTINUE...AS A WARMER AIR WORKS BACK IN FOR FRIDAY AND SATURDAY.
HIGHS FRIDAY WILL BE IN THE UPPER 30S TO LOWER 40S...WITH 40S FOR
HIGHS ON SATURDAY. TEMPERATURES WILL TAKE ANOTHER DOWN TURN ON
SUNDAY AS HIGHS WILL RANGE FROM THE MID 30S IN THE N TO MID 40S IN
NRN KY.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
MVFR CIGS WILL CONTINUE FOR THE MOST PART ACROSS THE AREA THROUGH
SUNRISE. A BREAK IN THE CLOUD COVER WILL ALLOW FOR A COUPLE OF
HOUR PERIOD OF VFR CONDITIONS DURING THE MIDDLE OF THE NIGHT FOR
ALL TERMINALS EXCEPT KLCK/KCMH. AFTER SUNRISE THE BACK EDGE OF
CLOUD COVER WILL SPREAD EAST ACROSS THE TERMINALS WITH VFR
CONDITIONS AND EXPECTED THEREAFTER FOR THE REMAINDER OF THE TAF
PERIOD. SOME VFR LOW TO MID LEVEL CLOUD COVER IS EXPECTED TO
SPREAD ACROSS THE AREA LATE MONDAY AFTERNOON AND EVENING.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...SITES
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1226 AM EST MON JAN 14 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE MIDWEST AND NOSE INTO THE OHIO
VALLEY FOR THE BEGINNING OF THE WEEK. A WEAK COLD FRONT WILL SKIRT
THE NORTHEAST OHIO VALLEY WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
COLD FRONT EXTENDS ACROSS THE FAR EASTERN COUNTIES AND WILL MOVE
OUT OF THE AREA IN THE NEXT COUPLE OF HOURS. RADAR SHOWS A SHARP
EDGE TO THE RAIN WHICH IS LAGGING THE FRONT BY A FEW HOURS. EXPECT
THE RAIN TO COME TO AN END BY 06Z. WITH THIS QUICK CUTOFF IT
APPEARS THAT PRECIPITATION WILL END BEFORE TEMPERATURES ARE COLD
ENOUGH FOR ANY WINTRY MIX. TIGHT GRADIENT IMMEDIATELY BEHIND THE
COLD FRONT HAS RESULT IN GUSTY WINDS. THESE SHOULD GRADUALLY
DIMINISH AS GRADIENT RELAXES. SATELLITE SHOWS CLEARING WORKING
INTO WESTERN INDIANA. RAP FORECASTS SEEM TO HAVE A REASONABLE
HANDLE ON THIS LOW LEVEL MOISTURE. THIS SUGGESTS THAT CLEARING
WILL WORK INTO THE FORECAST AREA LATER TONIGHT. FORECAST LOWS LOOK
REASONABLE WITH SOME MINOR ADJUSTMENTS TO TEMPERATURE DROP.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/...
I WAS UNABLE TO GO AS LOW ON THE CLOUD COVER WITH THE HIGH
PRESSURE BUILDING IN AS I WOULD LIKE. THOUGHT THE MOISTURE
BUILDING IN FROM THE NORTHWEST ON TUESDAY AND THE INCREASED
MOISTURE FROM THE SOUTHEAST ON MONDAY WOULD BATTLE FOR AT LEAST
SOME CLOUD COVER OVER THE REST OF THE CWA FOR SOME POINT IN TIME.
A VORTICITY MAXIMA IS NOTED SOMEWHAT AT H5 AND WILL SKIRT
SOUTHEAST CWA MONDAY EVENING...INCREASING THE THREAT FOR A PASSING
SNOW SHOWER FOR JUST A FEW COUNTIES SOUTH OF CHILLICOTHE AND EAST
OF MAYSVILLE. BOTH NAM AND GFS ARE HINTING AT A WEAK SHORTWAVE
WITH THIS VORT IN THE MEAN SOUTHWEST FLOW.
HIGH PRESSURE STRENGTHENING IN THE WAKE OF THE COLD FRONT WILL
HELP USHER IN MORE SEASONAL AND SIGNIFICANTLY COLDER TEMPERATURES
TO THE REGION.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
FORECAST PERIOD BEGINS WITH SFC HIGH PRESSURE RIDGING OVER THE FA.
THIS RIDGING GETS SHUNTED E QUICKLY ON WEDNESDAY AS A CDFNT SWINGS
THRU THE GREAT LAKES WED AFTN. MODELS ARE KEEPING THE BEST LIFT N OF
THE FA WITH THIS SYSTEM...SO KEPT THE FCST DRY. HIGH PRESSURE BUILDS
BACK INTO THE OH AND TN VALLEYS THU INTO FRI.
ENERGY KEEPS RUNNING THROUGH THE SUBTLE ERN U.S. LONGWAVE TROF OVER
THE WEEKEND. GFS AND ECMWF DIFFER ON THE STRENGTH OF A SYSTEM ON
SATURDAY....BUT BOTH PUSH COOLER AIR IN ON SUNDAY WITH A TRAILING
COLD FRONT. ONCE AGAIN THE MOISTURE IS LOOKING LIMITED FOR
SUNDAY...SO KEPT THE FCST DRY.
AS FOR TEMPERATURES...THE HIGH PRESSURE RIDGE ON WEDNESDAY WILL
ALLOW HIGHS TO CREEP INTO THE UPPER 30S TO LOWER 40S. COOLER AIR
BEHIND WEDNESDAYS SYSTEM WILL FILTER IN FOR THU...DROPPING HIGHS
INTO 30S. THE SEE-SAW TEMPERATURES WILL CONTINUE...AS A WARMER AIR
WORKS BACK IN FOR FRIDAY AND SATURDAY. HIGHS FRIDAY WILL BE IN THE
UPPER 30S TO LOWER 40S...WITH 40S FOR HIGHS ON SATURDAY.
TEMPERATURES WILL TAKE ANOTHER DOWN TURN ON SUNDAY AS HIGHS WILL
RANGE FROM THE MID 30S IN THE N TO MID 40S IN NRN KY.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
MVFR CIGS WILL CONTINUE FOR THE MOST PART ACROSS THE AREA THROUGH
SUNRISE. A BREAK IN THE CLOUD COVER WILL ALLOW FOR A COUPLE OF
HOUR PERIOD OF VFR CONDITIONS DURING THE MIDDLE OF THE NIGHT FOR
ALL TERMINALS EXCEPT KLCK/KCMH. AFTER SUNRISE THE BACK EDGE OF
CLOUD COVER WILL SPREAD EAST ACROSS THE TERMINALS WITH VFR
CONDITIONS AND EXPECTED THEREAFTER FOR THE REMAINDER OF THE TAF
PERIOD. SOME VFR LOW TO MID LEVEL CLOUD COVER IS EXPECTED TO
SPREAD ACROSS THE AREA LATE MONDAY AFTERNOON AND EVENING.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
323 AM CST MON JAN 14 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY
322 AM CST MON JAN 14 2013
AT 3 AM...A SURFACE TROUGH WAS LOCATED ACROSS SOUTHWEST MINNESOTA.
THIS TROUGH IS CURRENTLY PRODUCING A MVFR DECK OF CLOUDS ACROSS
EASTERN SOUTH DAKOTA AND SOUTHWEST MINNESOTA. THERE ARE EVEN
FLURRIES BEING REPORTED AT SIOUX FALLS SOUTH DAKOTA. FURTHER TO
THE SOUTHWEST...THE WATER VAPOR IMAGERY SHOWS A SHORT WAVE TROUGH
MOVING OUT OF COLORADO. THIS SYSTEM HAS BEEN PRODUCING SOME LIGHT
SNOW FROM COLORADO INTO CENTRAL SOUTH DAKOTA. THE 14.00Z MODELS
ARE IN GOOD AGREEMENT THAT THE SURFACE TROUGH WILL MOVE SLOWLY
EAST AND GRADUALLY WEAKEN TODAY. MEANWHILE THE SHORT WAVE WILL
MOVE ACROSS THE AREA THIS AFTERNOON. BOTH THE GFS AND NAM/WRF
SOUNDINGS SHOW LITTLE OMEGA WITH THESE SYSTEMS. MEANWHILE THE RAP
HAS UP TO 5 MICROBARS OF OMEGA CO-LOCATED WITH THE DENDRITIC
GROWTH ZONE. SINCE BOTH SYSTEMS ARE CURRENTLY PRODUCING SOME
FLURRIES OR VERY LIGHT SNOW...WENT MORE TOWARD THE RAP AND
INTRODUCED SOME SCATTERED FLURRIES FOR THIS AFTERNOON NORTHWEST OF
SAINT ANSGAR IOWA TO WISCONSIN RAPIDS LINE.
ON TUESDAY NIGHT AND WEDNESDAY...THE MODELS CONTINUE TO SHOW THAT
A LOW PRESSURE SYSTEM WILL MOVE ALONG THE ARCTIC COLD FRONT TO OUR
NORTH. AS THE WAVE APPROACHES...THE CLOUDS WILL INCREASE OVERNIGHT
AND TEMPERATURES WILL SLOWLY RISE. LIKE THE PAST COUPLE OF
DAYS...THE MODELS CONTINUE TO SHOW THAT THERE WILL BE ENOUGH
MOISTURE FOR SOME PRECIPITATION TO DEVELOP ALONG AND NORTH OF THE
INTERSTATE 90 CORRIDOR OVERNIGHT TUESDAY AND WEDNESDAY MORNING.
HOWEVER SOUNDINGS CONTINUE TO STRUGGLE ON WHETHER THERE WILL BE
ICE CRYSTAL SEEDING OR NOT. IN MANY CASES...WHERE THEY SHOW THE
LACK OF ICE...THERE IS NO PRECIPITATION. SINCE THERE IS NO CLEAR
SIGNAL...JUST KEPT THE PRECIPITATION IN THE FORM OF SNOW FOR NOW.
HOWEVER A BIT CONCERNED THAT THERE MAY BE SOME LIGHT FREEZING
DRIZZLE ON THE SOUTHERN PERIPHERY OF THE PRECIPITATION.
ANOTHER CONCERN ON WEDNESDAY IS THE TEMPERATURES...THE NAM/WRF HAS
WAY TOO MUCH SNOW COVER IN IT. THIS MODEL SHOWED 1 TO 2 INCHES OF
SNOW ON THE GROUND ACROSS NORTHEAST IOWA AND SOUTHEAST
MINNESOTA...AND 2 TO 5 INCHES OF SNOW ACROSS WESTERN WISCONSIN.
COOPERATIVE REPORTS AND NOHRSC SHOW THAT WITH THE EXCEPTION OF AN
INCH AT MEDFORD WISCONSIN...MUCH OF THE AREA IS SNOW FREE. DUE TO
THIS...THE NAM/WRF TEMPERATURES ARE WAY TOO COLD. TYPICALLY...AT
LA CROSSE THE MID-JANUARY MAXIMUM TEMPERATURES AVERAGE 10 DEGREES
WARMER THAN THE LONG TERM AVERAGE /24.7 DEGREES AT KLSE/ WHEN
THERE IS NO SNOW ON THE GROUND. THIS FITS IN WELL WITH A BLEND OF
THE GFS/ECMWF/GEM. WOULD NOT BE SURPRISED TO SEE SOME LOWER 40S
ACROSS SOUTHWEST WISCONSIN AND NORTHEAST IOWA.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
322 AM CST MON JAN 14 2013
ON THURSDAY AND THURSDAY NIGHT...THE 14.00Z MODELS CONTINUE TO
STRUGGLE ON HOW FAR SOUTH THE ARCTIC FRONT WILL GET. THE GFS HAS
THIS FRONT DROPPING SOUTH OF THE FORECAST AREA. MEANWHILE THE
NAM/WRF KEEPS THIS FRONT NORTH OF THE FORECAST AREA. THIS IS DUE
TO ANOTHER LOW PRESSURE SYSTEM QUICKLY FOLLOWING THE LOW THAT
PASSES TO THE NORTH OF THE AREA ON TUESDAY NIGHT AND WEDNESDAY.
MEANWHILE THE ECWMF IS A GOOD COMPROMISE BETWEEN THE TWO AND IT
HAS THIS FRONT ONLY GETTING AS FAR SOUTH AS THE INTERSTATE 94
CORRIDOR. DUE TO THESE DIFFERENCES...THERE IS LOWER THAN USUAL
CONFIDENCE IN THE TEMPERATURES. EVEN THE SNOWFALL FORECAST IS
UNCERTAIN DUE TO THE VARIOUS TIMING OF THE WAVES AND THE PLACEMENT
OF THE FRONT /THE SNOW WILL BE MAINLY CONFINED NORTH OF THIS
FRONT/.
ON FRIDAY...THE MODELS CONTINUE TO SHOW THAT A LOW PRESSURE AREA
WILL BE PASSING NORTH OF THE AREA. THE COMBINATION OF SOUTHWEST
WINDS AND SUNSHINE WILL ALLOW TEMPERATURES TO ONCE AGAIN WARM INTO
THE 30S AND LOWER 40S. THE ECMWF EVEN SUGGESTS LOWER AND MID 40S.
SINCE THIS HAS BEEN A CONSISTENT SIGNAL...RAISED THE ALL BLEND
TEMPERATURES BY ABOUT 5 DEGREES.
ON SUNDAY...THE MODELS CONTINUE TO STRUGGLE ON HOW FAR SOUTH THE
ARCTIC FRONT WILL SAG SOUTHWARD INTO THE AREA. A COUPLE OF DAYS
AGO THE ECMWF CONSISTENTLY SHOWED THAT THIS FRONT WOULD MOVE WELL
SOUTH OF THE AREA. THE 13.12Z ECMWF BACKED AWAY FROM THIS
SOLUTION...AND THE 14.00Z ECMWF HAS RETURNED BACK TO ITS COLDER
SOLUTION. SINCE THERE IS SOME UNCERTAINTY ON WHERE THIS FRONT WILL
BE LOCATED AND CONCERN ABOUT HOW MUCH MODERATION MAY TAKE PLACE
WITH THE LACK OF SNOW ACROSS THE AREA...JUST STAYED WITH THE ALL
BLEND FORECAST FOR NOW.
&&
.AVIATION...THROUGH 06Z TUESDAY
1136 PM CST SUN JAN 13 2013
SKIES HAVE CLEARED OUT AT BOTH TAF SITES DUE TO A WEAK RIDGE OF
HIGH PRESSURE THAT HAS MOVED IN. TO THE WEST...A TROUGH OF LOW
PRESSURE WAS MOVING INTO WESTERN MINNESOTA. ACCOMPANYING THE
TROUGH IS A BATCH OF MVFR STRATUS CROSSING FAR EASTERN SOUTH
DAKOTA. MODELS ARE IN GOOD AGREEMENT BRINGING THIS STRATUS INTO
KRST AROUND 16Z AND KLSE AROUND 18Z...THEN LASTING FOR 6-8 HOURS
BEFORE DRIER AIR MOVES BACK IN TO SCOUR THE CLOUDS OUT. GIVEN THAT
THERE WERE FLURRIES WITH THIS STRATUS DURING DAYTIME HEATING
YESTERDAY...HAVE MAINTAINED FLURRY POTENTIAL IN THE TAF. LOOK FOR
WINDS TO HOLD FAIRLY STEADY THROUGH 06Z TUESDAY...OUT OF THE
SOUTHWEST TO WEST AT 5-10 KT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
322 AM CST MON JAN 14 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
438 AM PST MON JAN 14 2013
...COLD TEMPERATURES THIS MORNING FOR MANY LOCATIONS...
.DISCUSSION...AS OF 4:15 AM PST MONDAY...HAVE CANCELLED THE FROST
ADVISORY FOR SAN FRANCISCO AND THE FREEZE WARNING FOR THE SAN
FRANCISCO SHORELINE. THERE HAS BEEN ENOUGH WIND TO KEEP THE
ATMOSPHERE MIXED...SO WHILE THE DEW PTS ARE VERY LOW TEMPERATURES
WILL REMAIN A BIT WARMER THAN EXPECTED. HAVE KEPT THE FREEZE
WARNING GOING TO 9 AM FOR THE INLAND VALLEYS OF THE DISTRICT AS
WELL AS THE SANTA CRUZ/MONTEREY COASTLINE. THE FREEZE WARNING FOR
THE NORTH BAY VALLEYS AND THE EAST BAY VALLEYS IS MARGINAL...BUT
IF THE WIND DIES OFF...TEMPERATURES WILL DROP RAPIDLY IN THE VERY
DRY AIRMASS. THE HRRR MODEL AND THE 00Z WRF BOTH ARE FORECASTING
LIGHT SFC WINDS THIS MORNING...SO WE WILL SEE HOW THIS PANS OUT.
DRY WEATHER WILL BE THE RULE FOR THE UPCOMING WEEK. A STRONG
RIDGE...CLEARLY SEEN ON WATER VAPOR IMAGERY IS CENTERED AROUND
140W...WITH THE RIDGE REACHING INTO ALASKA. INTERESTING TO NOTE
HOW FAR NORTH WARM AIR IS BEING ADVECTED INTO ALASKA...FAIRBANKS
IS CURRENTLY A (RELATIVELY) BALMY 28 DEGREES...WHEREAS THE AVERAGE
LOW IS -14 DEGREES! IN FACT...SAN MARTIN (BETWEEN MORGAN HILL AND
GILROY) IS THE SAME TEMPERATURE AS FAIRBANKS AT THIS TIME...VERY
RARELY SEEN IN THE MIDDLE OF JANUARY!
THE RIDGE WILL SLOWLY EDGE EAST...TO A POSITION ALONG THE COAST BY
THURSDAY...THEN REMAIN OVER THE WEST COAST RIGHT THROUGH THE
WEEKEND. AFTER ANOTHER COLD NIGHT TONIGHT...DEPENDING ON THE
WIND...TEMPERATURES WILL SLOWLY WARM THE REMAINDER OF THE WEEK AND
INTO THE WEEKEND. BOTH THE GFS AND ECMWF BEGIN TO BREAK DOWN THE
RIDGE BY THE MIDDLE OF NEXT WEEK (JANUARY 23).
&&
.AVIATION...AS OF 3:15 AM PST MONDAY...VERY DRY AIRMASS IN PLACE
THIS MORNING WITH CLEAR SKIES AND VFR CONDITIONS. CURRENT TAF
PACKAGE WILL CONTINUE VFR THROUGH THE FORECAST PERIOD. ONLY TRICKY
PART ARE THE EASTERLY WINDS...ESP AROUND SAN FRANCISCO BAY. CONF HIGH.
VICINITY OF KSFO...VFR CONDITIONS. WINDS AS OF 11Z ARE SE AROUND
THE BAY. WILL KEEP SE PREVAILING...BUT MODEL GUIDANCE SUGGESTS A
NE FLOW AROUND 10 KT LATER THIS MORNING. CONF IS MARGINAL AND WILL
LEAVE THE NE FLOW OUT FOR NOW. WILL MONITOR AND AMEND SFO IF
NEEDED. OTHERWISE...NW FLOW LATER TODAY.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR CONDITIONS.
&&
.CLIMATE...HERE ARE THE RECORD LOW TEMPERATURES FOR JANUARY 14TH
AT SELECTED LOCATIONS...
SAN FRANCISCO BAY AREA
.LOCATION....................JAN 14
SANTA ROSA.................21/1963
KENTFIELD..................25/1949
SAN RAFAEL.................28/2007
NAPA.......................24/1963
SAN FRANCISCO..............29/1888
SFO........................31/1963
OAKLAND....................33/2007
OAKLAND AIRPORT............28/2007
RICHMOND...................31/1955
LIVERMORE..................21/1963
MOUNTAIN VIEW..............28/2007
SAN JOSE...................28/1997
GILROY.....................19/1963
MONTEREY BAY AREA
.LOCATION....................JAN 14
MONTEREY...................30/1997
SANTA CRUZ.................22/1963
SALINAS....................24/2007
SALINAS AIRPORT............25/2007
KING CITY..................17/2007
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...FREEZE WARNING...INTERIOR VALLEYS OF THE SAN FRANCISCO
AND MONTEREY BAY AREAS AND THE SANTA
CRUZ/MONTEREY COASTLINE.
&&
$$
PUBLIC FORECAST: STROBIN
AVIATION/MARINE: MM
CLIMATE: HENDERSON/BELL
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AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1045 AM EST MON JAN 14 2013
.UPDATE (REST OF TODAY THROUGH TUESDAY)...
15Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A CONTINUED HIGHLY
AMPLIFIED UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS. PATTERN IS
DOMINATED BY A LARGE AND IMPRESSIVE LONGWAVE TROUGH COVERING ALMOST
THE ENTIRE CONUS. THE LAST DOMAIN OF THE ONCE PROMINENT UPPER RIDGE
ALONG THE EAST COAST IS ACROSS THE FAR SOUTHEASTERN STATES.
LUCKILY...THIS INCLUDES US AND WILL ALLOW OUR GENERALLY DRY AND WARM
WEATHER TO CONTINUE FOR ANOTHER COUPLE OF DAYS.
UPPER LEVEL JET AND HIGH LEVEL MOISTURE AXIS IS LOCATED WELL OFF TO
OUR NORTHWEST TODAY...AND HENCE WE SHOULD SEE MUCH LESS IN THE WAY
OF HIGH LEVEL CIRRUS COMPARED TO WHAT OCCURRED ON SUNDAY.
HOWEVER...SIMILAR TO PREVIOUS DAYS...WE WILL SEE THE DEVELOPMENT OF
A SCT-BKN SHALLOW CU FIELD WITHIN THE SOUTHEAST LOW LEVEL FLOW BY
THE EARLY AFTERNOON HOURS.
MORNING SOUNDINGS HAVE A VERY SIMILAR MID/LOW LEVEL PROFILE THE PAST
FEW DAYS...AND THAT PATTERN CONTINUES THIS MORNING WITH A
WELL-DEFINED SUBSIDENCE INVERSION AROUND 850MB UNDERNEATH THE
SUPPRESSION OF THE UPPER RIDGE. EXPECT DIURNAL MIXING BY LATE
AFTERNOON UP TO AROUND 5000 FEET AND WITH 850MB TEMPS IN THE 14-15C
RANGE...THIS SHOULD MIX OUT NICELY TO HIGH TEMPS IN THE LOWER 80S
AWAY FROM THE IMMEDIATE COAST. THE WEAK GRADIENT AND STRONG LAND
BASED HEATING SHOULD BE ENOUGH TO TURN WINDS ONSHORE AT THE BEACHES
DURING THE AFTERNOON WITH FEEBLE SEA-BREEZE DEVELOPMENT. MOST OF THE
HIRES GUIDANCE IS SHOWING THIS WIND SHIFT BY 19-20Z...AND THIS
SHOULD KEEP THE IMMEDIATE COAST A FEW DEGREES COOLER.
MORE OF THE SAME FOR TONIGHT INTO TUESDAY AS THE STACKED RIDGING
HOLDS ON JUST A LITTLE BIT LONGER. STATIC SYNOPTIC PATTERNS
GENERALLY YIELD STATIC WEATHER. THIS FORECAST WILL REFLECT THAT
PHILOSOPHY WITH SOME PATCHY FOG AND LOW CLOUDS DURING THE LATE NIGHT
/ EARLY MORNING HOURS OF TUESDAY...THEN HAVING ANY FOG BURN OFF BY
AROUND 900 AM. AFTERNOON TEMPS WILL CLIMB TO WITHIN A FEW DEGREES OF
80 INLAND...AND A FEW DEGREES COOLER AT THE BEACHES WITH AN ONSHORE
AFTERNOON BREEZE. ENJOY!
&&
.AVIATION...
MORNING FOG JUST ABOUT GONE WITH MAINLY VFR REST OF THE DAY. PATCHY
FOG POSSIBLE AGAIN TONIGHT WITH MAIN IMPACTS EXPECTED AT PGD.
&&
.MARINE...
HIGH PRESSURE NORTH OF THE BAHAMAS WILL CONTINUE TO RIDGE BACK TO
THE WEST ACROSS THE FLORIDA PENINSULA AND EASTERN GULF OF MEXICO
THROUGH WEDNESDAY. A COLD FRONT WILL THEN CROSS THE FORECAST WATERS
DURING THURSDAY WITH A WIND SHIFT TO THE NORTH IN ITS WAKE BY
THURSDAY NIGHT AND FRIDAY. A PERIOD OF CAUTIONARY TO ADVISORY LEVEL
WINDS AND SEAS WILL ALSO BE POSSIBLE IN THE WAKE OF THIS FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 80 63 78 62 / 0 0 05 05
FMY 80 63 80 62 / 0 0 05 05
GIF 80 59 81 59 / 0 0 05 05
SRQ 78 60 77 61 / 0 0 05 05
BKV 81 53 81 55 / 0 0 05 05
SPG 78 64 76 65 / 0 0 05 05
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
645 AM EST MON JAN 14 2013
.AVIATION... /12 UTC TAFS/
ONLY MINOR CHNGS WRT LATEST TAFS. LEADING EDGE CLEARING SLOWING
INVOF KSBN PER LAKE INFLUENCE...THOUGH CIGS SHOULD BE VFR/UNLIMITED
BY ABOUT 14-1430 UTC AT KSBN AIRFIELD. END OF FUEL ALT CONDS MORE
IMMINENT AT KFWA...WITH VFR CONDS ASSURED THROUGH THE END OF THE
FCST PD.
&&
.SHORT TERM... /TODAY THROUGH TUESDAY NIGHT/
NMRS MESOGAMMA THERMAL ROLLS CRNTLY BLOSSOMING WSR-88 VCP 31
RETURNS ERLY THIS MORNING...EXTNDG FARTHER SOUTH THAN TYPICAL LAKE
RESPONSE...AT LEAST TO KRCR-WABASH LN. LK MSTR ENHANCEMENT RATHER
MINIMAL GIVEN ONLY LWR TEENS LK/8H THERMAL DIFFERENTIAL ACRS FAR
SRN LK MI. THIN LYR LIFT ON NOSE OF 30-35KT 8H JETLET/SHORTWAVE FM
NRN IL AT 03 UTC. 8H PSUEDOFRONT APPEARS ORTHOGONALLY ALONG
LEADING EDGE OF RAP ANALYZED THIN LYR NEAR SFC/950-900 MB/ FGEN
ZONE LAID OUT SRN LK HUR-SERN FA-SRN IN...WHICH SHOULD QUELL
FLURRIES MENTION BY ABOUT 14 UTC. THIS THE ONLY SENSIBLE WX IN THE
SHORT TERM PD. THEREAFTER...THE DEEP SCOUR OF MSTR BY CP CANADIAN
PLAINS AIRMASS TO CONT TO ERODE RMNG STRATOCU FIELD TDY ON LEADING
EDGE OF 1034MB RIDGE. ANTICIPATE POOR THERMAL RECOVERY THOUGH IN
LIGHT OF SIG AIRMASS EXCHANGE ALONG WITH POTNL INCRS IN CI/CS LTR
THIS AFTN ASSOCD WITH INTENSE ULVL JETSTREAK ON ORDER OF 180-200
KTS LIFTG THROUGH MID MS VLY TO FAR SRN ONT THIS EVE. GOOD POTNL
FOR DECOUPLED BLYR LATE TONIGHT. DOWN TO LWR TEENS/PSBLY LWR
SINGLE DIGITS...SPCLY FAR WRN CWA WITH BEST DURATION FOR LONGWAVE
LOSSES. SLIGHT SFC- 925MB THERMAL MODIFICATION BY DAYBREAK
WED...ALONG WITH INCRSD MIXED BL...WITH CWA ON SERN PERIPHERY OF
RAMPING FLOW ASSOCD WITH HIGH BELTED CLIPPER.
&&
.LONG TERM... /WEDNESDAY THROUGH SUNDAY/
A LONGWAVE TROF WILL AMPLIFY OVER EASTERN NORTH AMERICA THIS
PERIOD AS A PRECURSOR OF THE ARRIVAL OF VERY COLD AIR LATE IN THE
PERIOD. THE 500 MB GFS AND CANADIAN ANALOGS...GFS AND CANADIAN
ENSEMBLES AND THE ECMWF ALL SUPPORT THE ESTABLISHMENT OF A MUCH
COLDER PATTERN EARLY NEXT WEEK. AHEAD OF THE AMPLIFYING UPPER
TROF...A WEAKER TROF WILL MOVE ACROSS THE AREA ACCOMPANIED BY A
COLD FRONT WEDNESDAY NIGHT. THERE IS NOT MUCH SUPPORT FOR
PRECIPITATION WITH THIS SYSTEM INCLUDING LAKE EFFECT SNOW.
MOISTURE IS LIMITED AND FORCING IS WEAK. THE MOST UNSTABLE LAKE
EFFECT DELTA T VALUES BEFORE SUNDAY ARE 10 TO 14...BUT WITH AN
UNFAVORABLE FETCH OVER MUCH OF THE PERIOD...KEPT THE FORECAST DRY.
FOR LATE IN THE PERIOD...GUT FEELING HIGHS SUNDAY ARE TOO WARM.
HOWEVER...LEFT HIGHS AROUND 30 MOST AREAS GIVEN THE UNCERTAINTY OF
THE ARRIVAL TIME OF THE FRONT. THE GFS MEAN ENSEMBLE MOS HIGHS
SUNDAY ARE 22 TO 27 WHICH MAY BE ON TRACK. A PERIOD OF LIGHT SNOW
IN THE ARCTIC AIR MAY ALSO EVENTUALLY NEED TO BE ADDED TO THE
FORECAST SUNDAY IF A FASTER FRONTAL PASSAGE PREVAILS. TEMPERATURES
MAY BE STEADY OR SLOWING FALLING SUNDAY. FOR NOW...WENT WITH A
SMALL DIURNAL RISE SUNDAY.
&&
.MARINE...
LOOK FOR RAPIDLY INCRSG GRADIENT FLOW AS ULVL TROF SHIFTS GRDLY
EWD INTO WRN GRTLKS BY LATE TUE. MIDWEEK MARINE HEADLINES TO LATER
FOCUS ON NEED FOR NEARSHORE GALE WATCH/WARNING WITH BEST WINDOW IN
THE 12-21 UTC WED TIMEFRAME. ACCELERATION RATE OF FLOW SHOULD
PRECLUDE LEAD IN SC.Y...THOUGH LATER FCSTS TO FINE TUNE AS NEED
BE.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LMZ043-046.
&&
$$
SHORT TERM...MURPHY
LONG TERM...SKIPPER
AVIATION...MURPHY
MARINE...MURPHY
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
523 AM EST MON JAN 14 2013
.SHORT TERM... /TODAY THROUGH TUESDAY NIGHT/
NMRS MESOGAMMA THERMAL ROLLS CRNTLY BLOSSOMING WSR-88 VCP 31
RETURNS ERLY THIS MORNING...EXTNDG FARTHER SOUTH THAN TYPICAL LAKE
RESPONSE...AT LEAST TO KRCR-WABASH LN. LK MSTR ENHANCEMENT RATHER
MINIMAL GIVEN ONLY LWR TEENS LK/8H THERMAL DIFFERENTIAL ACRS FAR
SRN LK MI. THIN LYR LIFT ON NOSE OF 30-35KT 8H JETLET/SHORTWAVE FM
NRN IL AT 03 UTC. 8H PSUEDOFRONT APPEARS ORTHOGONALLY ALONG
LEADING EDGE OF RAP ANALYZED THIN LYR NEAR SFC/950-900 MB/ FGEN
ZONE LAID OUT SRN LK HUR-SERN FA-SRN IN...WHICH SHOULD QUELL
FLURRIES MENTION BY ABOUT 14 UTC. THIS THE ONLY SENSIBLE WX IN THE
SHORT TERM PD. THEREAFTER...THE DEEP SCOUR OF MSTR BY CP CANADIAN
PLAINS AIRMASS TO CONT TO ERODE RMNG STRATOCU FIELD TDY ON LEADING
EDGE OF 1034MB RIDGE. ANTICIPATE POOR THERMAL RECOVERY THOUGH IN
LIGHT OF SIG AIRMASS EXCHANGE ALONG WITH POTNL INCRS IN CI/CS LTR
THIS AFTN ASSOCD WITH INTENSE ULVL JETSTREAK ON ORDER OF 180-200
KTS LIFTG THROUGH MID MS VLY TO FAR SRN ONT THIS EVE. GOOD POTNL
FOR DECOUPLED BLYR LATE TONIGHT. DOWN TO LWR TEENS/PSBLY LWR
SINGLE DIGITS...SPCLY FAR WRN CWA WITH BEST DURATION FOR LONGWAVE
LOSSES. SLIGHT SFC- 925MB THERMAL MODIFICATION BY DAYBREAK
WED...ALONG WITH INCRSD MIXED BL...WITH CWA ON SERN PERIPHERY OF
RAMPING FLOW ASSOCD WITH HIGH BELTED CLIPPER.
&&
.LONG TERM... /WEDNESDAY THROUGH SUNDAY/
A LONGWAVE TROF WILL AMPLIFY OVER EASTERN NORTH AMERICA THIS
PERIOD AS A PRECURSOR OF THE ARRIVAL OF VERY COLD AIR LATE IN THE
PERIOD. THE 500 MB GFS AND CANADIAN ANALOGS...GFS AND CANADIAN
ENSEMBLES AND THE ECMWF ALL SUPPORT THE ESTABLISHMENT OF A MUCH
COLDER PATTERN EARLY NEXT WEEK. AHEAD OF THE AMPLIFYING UPPER
TROF...A WEAKER TROF WILL MOVE ACROSS THE AREA ACCOMPANIED BY A
COLD FRONT WEDNESDAY NIGHT. THERE IS NOT MUCH SUPPORT FOR
PRECIPITATION WITH THIS SYSTEM INCLUDING LAKE EFFECT SNOW.
MOISTURE IS LIMITED AND FORCING IS WEAK. THE MOST UNSTABLE LAKE
EFFECT DELTA T VALUES BEFORE SUNDAY ARE 10 TO 14...BUT WITH AN
UNFAVORABLE FETCH OVER MUCH OF THE PERIOD...KEPT THE FORECAST DRY.
FOR LATE IN THE PERIOD...GUT FEELING HIGHS SUNDAY ARE TOO WARM.
HOWEVER...LEFT HIGHS AROUND 30 MOST AREAS GIVEN THE UNCERTAINTY OF
THE ARRIVAL TIME OF THE FRONT. THE GFS MEAN ENSEMBLE MOS HIGHS
SUNDAY ARE 22 TO 27 WHICH MAY BE ON TRACK. A PERIOD OF LIGHT SNOW
IN THE ARCTIC AIR MAY ALSO EVENTUALLY NEED TO BE ADDED TO THE
FORECAST SUNDAY IF A FASTER FRONTAL PASSAGE PREVAILS. TEMPERATURES
MAY BE STEADY OR SLOWING FALLING SUNDAY. FOR NOW...WENT WITH A
SMALL DIURNAL RISE SUNDAY.
&&
.AVIATION... /06 UTC TAFS/
INCRSD ENTRAINMENT OF DRIER AIR ACRS NRN IL/SRN WI CIRCUITOUSLY VIA
LAND/AROUND SRN TIP OF LK MI AND INTO NRN IN. THIS SHOULD SUPPORT A
MORE RAPID RECOVERY OUT OF FUEL ALT CONDS AT KSBN/AROUND 10 UTC.
THIS APPROX SAME TIME AS KFWA WHERE LAKE INFLUENCE LACKS IN BACKED
WRLY/CROSS SHORT LAKE AXIS FLOW.
&&
.MARINE...
LOOK FOR RAPIDLY INCRSG GRADIENT FLOW AS ULVL TROF SHIFTS GRDLY
EWD INTO WRN GRTLKS BY LATE TUE. MIDWEEK MARINE HEADLINES TO LATER
FOCUS ON NEED FOR NEARSHORE GALE WATCH/WARNING WITH BEST WINDOW IN
THE 12-21 UTC WED TIMEFRAME. ACCELERATION RATE OF FLOW SHOULD
PRECLUDE LEAD IN SC.Y...THOUGH LATER FCSTS TO FINE TUNE AS NEED
BE.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LMZ043-046.
&&
$$
SHORT TERM...MURPHY
LONG TERM...SKIPPER
AVIATION...MURPHY
MARINE...MURPHY
AREA FORECAST DISCUSSION
NWS CARIBOU ME
903 AM EST MON JAN 14 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION BY AFTERNOON. MUCH COLDER
TEMPERATURES ARE EXPECTED BEHIND THE FRONT FOR TONIGHT AND
TUESDAY. AFTER A BRIEF RESPITE WEDNESDAY...AN ARCTIC FRONT WILL
CROSS THE REGION THURSDAY AND BRING BITTERLY COLD AIR FOR LATE
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
900 AM UPDATE...ADDED NORTHERN 1/2 OF THE CWA IN A DENSE FOG
ADVISORY THROUGH 11 AM. THIS WILL BE MAINLY ACROSS THE HIGHER TERRAIN.
THE CANADIAN GEM DOING A FINE JOB IN PICKING THE FOG UP AS WELL AS
THE RUC THIS MORNING IN THESE AREAS. DEWPOINTS RISING ALLOW FOR
SOME MELTING OF THE SNOWPACK W/SSE WINDS ACROSS THE NORTH ALLOWING
FOR DENSE FOG.
ACROSS THE CENTRAL AND DOWNEAST AREAS, THE FOG IS BEGINNING TO
LIFT W/VSBYS IMPROVING, SO ADJUSTMENTS HAVE BEEN MADE AND THE
DENSE FOG ADVISORY HAS BEEN ALLOWED TO EXPIRE. SUNSHINE LATER THIS
MORNING INT THE AFTERNOON WILL ALLOW FOR TEMPERATURES IN THESE
AREAS TO WARM IN THE UPPER 40S TO POSSIBLY 50 DEGREES. WE WILL
ASSESS MENTIONED IN THE PREVIOUS DISCUSSION...RAIN SHOWERS HAVE
INDEED BEGUN MOVING INTO CENTRAL AND SOUTHERN PORTIONS OF THE
FORECAST AREA. HAVE INCREASED POPS TO LIKELY IN THESE AREAS. NO
OTHER CHANGES NEEDED.
PREVIOUS DISCUSSION...WIDESPREAD FOG WILL CONTINUE THROUGH THE
EARLY MORNING HOURS AS MOIST SOUTHWEST FLOW STREAMS INTO THE
FORECAST AREA AHEAD OF AN APPROACHING COLD FRONT. WITH VISIBILITY
STILL AT OR BELOW ONE HALF MILE, THE DENSE FOG ADVISORY REMAINS IN
PLACE UNTIL 8 AM FOR DOWNEAST AREAS. UPSTREAM RADARS SHOW RAIN
ASSOCIATED WITH THE FRONT CURRENTLY MOVING INTO NEW YORK. THIS
PRECIPITATION WILL CONTINUE TO PUSH EASTWARD ALONG WITH THE FRONT,
ENTERING NORTHWESTERN MAINE BY AROUND DAYBREAK. THE FRONT WILL
CROSS THE AREA DURING THE MORNING HOURS, MOVING OFFSHORE BY EARLY
AFTERNOON. THEREFORE EXPECT THE RAIN WILL QUICKLY COME TO AN END
SHORTLY AFTER NOON. WHILE THE BULK OF THE PRECIPITATION WILL BE
OVER NORTHERN PORTIONS OF THE FORECAST AREA, HAVE NOTED THAT SOME
OF THE LATEST GUIDANCE, INCLUDING THE 3KM HRRR MODEL, INDICATES
THAT THE RAIN WILL HOLD TOGETHER OVER DOWNEAST MAINE AS WELL. HAVE
THEREFORE BUMPED UP POPS THERE A BIT THROUGH MID-MORNING, BUT THEY
MAY HAVE TO BE INCREASED LATER AS TRENDS BECOME ESTABLISHED.
TEMPERATURES WILL RISE SLIGHTLY THIS MORNING WITH HIGHS RANGING
FROM THE LOWER 40S IN THE NORTH AND WEST TO MID AND UPPER 40S
DOWNEAST. ONCE THE FRONT COMES THROUGH, TEMPERATURES WILL QUICKLY
DROP UNDER BRISK NORTHWEST WINDS.
HIGH PRESSURE WILL SLOWLY BUILD OVER THE REGION TONIGHT. EXPECT
CLEARING SKIES AND DECREASING WINDS. ALTHOUGH OVERNIGHT TEMPS WILL
REMAIN ABOVE NORMAL, IT WILL BE MUCH COLDER THAN READINGS OVER THE
PAST COUPLE OF NIGHTS. LOWS WILL RANGE FROM THE SINGLE DIGITS IN THE
NORTH TO THE UPPER TEENS DOWNEAST. COASTAL AREAS WILL REMAIN IN THE
LOWER 20S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
FAIR AND COLDER CONDITIONS IS XPCTD TUE INTO TUE NGT AS SEMI-
ARCTIC SFC HI PRES CROSSES THE REGION. RETURN SRLY FLOW WILL OCCUR
ON WED BEHIND THIS HI AS IT MOVES INTO THE MARITIMES. IN THE MEANTIME...
A FLAT S/WV TRACKING ENE FROM SE NEW ENG S OF THE GULF OF ME WILL
BRING DOWNEAST PTNS OF THE FA INCREASING CLDS WED WITH A CHC OF LGT
RN/SN LATE WED INTO WED EVE ALG THE COAST AND MSLY OVR THE ADJACENT
COASTAL WATERS. IMMEDIATELY FOLLOWING THIS SYSTEM....A STRONG
ARCTIC FRONT WILL APCH WRN PTNS OF THE FA LATE WED NGT WITH SOME
CLDNSS AND A CHC OF SN SHWRS. TEMPS WILL BE A LITTLE MILDER ON
WED AND WED NGT WITH THE RETURN SRLY FLOW THAN TUE AND TUE NGT
WHICH WILL FEATURE NEAR SEASONAL TEMPS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
LONGER RANGE MODELS GENERALLY AGREE WITH MINOR TMG DIFFERENCES THAT
THE ARCTIC FRONT WILL CROSS THE REGION THU MORN...WITH MOST OF
SCT SN SHWRS OVR NW AND FAR NE PTNS OF THE REGION DURING THE
PASSAGE OF THE FRONT. MUCH COLDER TEMPS FOLLOW FOR THU NGT THRU
FRI NGT...WITH HI TEMPS WE SHOW FRI ACROSS THE REGION LIKELY
OPTIMISTIC. HI CLDS COULD BEGIN INCREASING ACROSS OUR REGION FROM
AN ADVCG S/WV FROM THE GREAT LKS AS EARLY AS LATE FRI NGT...BUT
WILL LIKELY HOLD OFF UNTIL SAT.
THE 00Z DTMNSTC GFS AND ECMWF CAME INTO BETTER AGREEMENT WITH THE
TMG OF THE GREAT LKS S/WV...BRINGING OVRRNG SNFL TO THE FA...SPCLY
NRN PTNS SAT NGT INTO SUN. OF THE TWO MODELS...THE GFS ACTUALLY
BRINGS SIG QPF ACROSS THE N HLF OF THE REGION WITH THIS SYSTEM AS
THE SFC TRACKS OVR OR JUST N OF THE FA...WITH LESSER AMTS SHOWN BY
THE ECMWF. FOR NOW...WE WILL INCREASE POPS TO HI CHC FOR STRATIFORM
SN UP TO 50 PERCENT FOR THE N....WITH LESSER POPS CNTRL AND DOWNEAST
AREAS. ANY STEADY SN SHOULD WIND DOWN AS SN SHWRS SUN AFTN AND SUN
NGT BEHIND THIS LOW AS IT MOVES INTO THE CAN MARITIMES...WITH
POTENTIALLY ANOTHER SHOT OF BITTERLY COLD ARCTIC AIR ADVCTG INTO
THE REGION BY LATE SUN NGT INTO MON. WE DO NOT INDICATE THE
POTENTIAL MAGNITUDE OF THIS AIR MASS WITH REGARD TO TEMPS SUN
NGT ATTM DUE TO UNCERTAINTY DUE TO PREVIOUS TMG DIFFERENCES
BETWEEN LONGER RANGE MODELS IN PAST MODEL RUNS...BUT AS WE GET
CLOSER TO THIS EVENT...MORE REALISTIC TEMPS WILL BE SHOWN.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
NEAR TERM: WIDESPREAD IFR WILL CONTINUE THROUGH AT LEAST 13Z-14Z.
WHILE FOG MAY LIFT SOMEWHAT TOWARD DAYBREAK, RAIN ASSOCIATED WITH
A COLD FRONT WILL KEEP CEILINGS IN THE IFR CATEGORY INTO MID-
MORNING. CONDITIONS WILL GRADUALLY IMPROVE THEREAFTER, WITH ALL
SITES REACHING VFR STATUS 18Z-20Z.
SHORT TO LONG TERM: VFR XPCTD...XCPT BRIEF MVFR CONDITIONS
POSSIBLE WITH SN SHWRS ACROSS NRN TAF SITES JUST AHEAD AND DURG
THE PASSAGE OF AN ARCTIC COLD FRONT LATE WED NGT AND THU MORN.
&&
.MARINE...
NEAR TERM: SCA REMAINS IN EFFECT TODAY INTO TONIGHT. A COLD FRONT
WILL MOVE ACROSS THE WATERS LATE THIS MORNING, TURNING SOUTHWEST
WINDS 15 TO 20 KT TO THE NORTHWEST AND INCREASING THEM TO 20 TO 30
KT. THE WINDS WILL SUBSIDE LATER TONIGHT ONCE THE INITIAL COLD
ADVECTION HAS PASSED.
SHORT TO LONG TERM: INITIALLY NO HDLNS TUE INTO WED MORN...THEN
WINDS AND SEAS APCHG AND REACHING SCA CONDITIONS FOR WED AFTN INTO
THUS MORN AHEAD TO JUST BEHIND THE ARCTIC COLD FRONT. CONDITIONS LOWER
BLO SCA CONDITIONS LATER THU INTO THU NGT AND CONT INTO FRI. KEPT
CLOSE TO FCST WW3 GUIDANCE FOR WV HTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...DENSE FOG ADVISORY UNTIL 11 AM EST THIS MORNING FOR MEZ001>006.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...HASTINGS/HEWITT
SHORT TERM...VJN
LONG TERM...VJN
AVIATION...HASTINGS/HEWITT
MARINE...HASTINGS/HEWITT/VJN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
742 AM EST MON JAN 14 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION BY AFTERNOON. MUCH COLDER
TEMPERATURES ARE EXPECTED BEHIND THE FRONT FOR TONIGHT AND
TUESDAY. AFTER A BRIEF RESPITE WEDNESDAY...AN ARCTIC FRONT WILL
CROSS THE REGION THURSDAY AND BRING BITTERLY COLD AIR FOR LATE
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
520 AM UPDATE...AS MENTIONED IN THE PREVIOUS DISCUSSION...RAIN
SHOWERS HAVE INDEED BEGUN MOVING INTO CENTRAL AND SOUTHERN
PORTIONS OF THE FORECAST AREA. HAVE INCREASED POPS TO LIKELY IN
THESE AREAS. NO OTHER CHANGES NEEDED.
PREVIOUS DISCUSSION...WIDESPREAD FOG WILL CONTINUE THROUGH THE
EARLY MORNING HOURS AS MOIST SOUTHWEST FLOW STREAMS INTO THE
FORECAST AREA AHEAD OF AN APPROACHING COLD FRONT. WITH VISIBILITY
STILL AT OR BELOW ONE HALF MILE, THE DENSE FOG ADVISORY REMAINS IN
PLACE UNTIL 8 AM FOR DOWNEAST AREAS. UPSTREAM RADARS SHOW RAIN
ASSOCIATED WITH THE FRONT CURRENTLY MOVING INTO NEW YORK. THIS
PRECIPITATION WILL CONTINUE TO PUSH EASTWARD ALONG WITH THE FRONT,
ENTERING NORTHWESTERN MAINE BY AROUND DAYBREAK. THE FRONT WILL
CROSS THE AREA DURING THE MORNING HOURS, MOVING OFFSHORE BY EARLY
AFTERNOON. THEREFORE EXPECT THE RAIN WILL QUICKLY COME TO AN END
SHORTLY AFTER NOON. WHILE THE BULK OF THE PRECIPITATION WILL BE
OVER NORTHERN PORTIONS OF THE FORECAST AREA, HAVE NOTED THAT SOME
OF THE LATEST GUIDANCE, INCLUDING THE 3KM HRRR MODEL, INDICATES
THAT THE RAIN WILL HOLD TOGETHER OVER DOWNEAST MAINE AS WELL. HAVE
THEREFORE BUMPED UP POPS THERE A BIT THROUGH MID-MORNING, BUT THEY
MAY HAVE TO BE INCREASED LATER AS TRENDS BECOME ESTABLISHED.
TEMPERATURES WILL RISE SLIGHTLY THIS MORNING WITH HIGHS RANGING
FROM THE LOWER 40S IN THE NORTH AND WEST TO MID AND UPPER 40S
DOWNEAST. ONCE THE FRONT COMES THROUGH, TEMPERATURES WILL QUICKLY
DROP UNDER BRISK NORTHWEST WINDS.
HIGH PRESSURE WILL SLOWLY BUILD OVER THE REGION TONIGHT. EXPECT
CLEARING SKIES AND DECREASING WINDS. ALTHOUGH OVERNIGHT TEMPS WILL
REMAIN ABOVE NORMAL, IT WILL BE MUCH COLDER THAN READINGS OVER THE
PAST COUPLE OF NIGHTS. LOWS WILL RANGE FROM THE SINGLE DIGITS IN THE
NORTH TO THE UPPER TEENS DOWNEAST. COASTAL AREAS WILL REMAIN IN THE
LOWER 20S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
FAIR AND COLDER CONDITIONS IS XPCTD TUE INTO TUE NGT AS SEMI-
ARCTIC SFC HI PRES CROSSES THE REGION. RETURN SRLY FLOW WILL OCCUR
ON WED BEHIND THIS HI AS IT MOVES INTO THE MARITIMES. IN THE MEANTIME...
A FLAT S/WV TRACKING ENE FROM SE NEW ENG S OF THE GULF OF ME WILL
BRING DOWNEAST PTNS OF THE FA INCREASING CLDS WED WITH A CHC OF LGT
RN/SN LATE WED INTO WED EVE ALG THE COAST AND MSLY OVR THE ADJACENT
COASTAL WATERS. IMMEDIATELY FOLLOWING THIS SYSTEM....A STRONG
ARCTIC FRONT WILL APCH WRN PTNS OF THE FA LATE WED NGT WITH SOME
CLDNSS AND A CHC OF SN SHWRS. TEMPS WILL BE A LITTLE MILDER ON
WED AND WED NGT WITH THE RETURN SRLY FLOW THAN TUE AND TUE NGT
WHICH WILL FEATURE NEAR SEASONAL TEMPS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
LONGER RANGE MODELS GENERALLY AGREE WITH MINOR TMG DIFFERENCES THAT
THE ARCTIC FRONT WILL CROSS THE REGION THU MORN...WITH MOST OF
SCT SN SHWRS OVR NW AND FAR NE PTNS OF THE REGION DURING THE
PASSAGE OF THE FRONT. MUCH COLDER TEMPS FOLLOW FOR THU NGT THRU
FRI NGT...WITH HI TEMPS WE SHOW FRI ACROSS THE REGION LIKELY
OPTIMISTIC. HI CLDS COULD BEGIN INCREASING ACROSS OUR REGION FROM
AN ADVCG S/WV FROM THE GREAT LKS AS EARLY AS LATE FRI NGT...BUT
WILL LIKELY HOLD OFF UNTIL SAT.
THE 00Z DTMNSTC GFS AND ECMWF CAME INTO BETTER AGREEMENT WITH THE
TMG OF THE GREAT LKS S/WV...BRINGING OVRRNG SNFL TO THE FA...SPCLY
NRN PTNS SAT NGT INTO SUN. OF THE TWO MODELS...THE GFS ACTUALLY
BRINGS SIG QPF ACROSS THE N HLF OF THE REGION WITH THIS SYSTEM AS
THE SFC TRACKS OVR OR JUST N OF THE FA...WITH LESSER AMTS SHOWN BY
THE ECMWF. FOR NOW...WE WILL INCREASE POPS TO HI CHC FOR STRATIFORM
SN UP TO 50 PERCENT FOR THE N....WITH LESSER POPS CNTRL AND DOWNEAST
AREAS. ANY STEADY SN SHOULD WIND DOWN AS SN SHWRS SUN AFTN AND SUN
NGT BEHIND THIS LOW AS IT MOVES INTO THE CAN MARITIMES...WITH
POTENTIALLY ANOTHER SHOT OF BITTERLY COLD ARCTIC AIR ADVCTG INTO
THE REGION BY LATE SUN NGT INTO MON. WE DO NOT INDICATE THE
POTENTIAL MAGNITUDE OF THIS AIR MASS WITH REGARD TO TEMPS SUN
NGT ATTM DUE TO UNCERTAINTY DUE TO PREVIOUS TMG DIFFERENCES
BETWEEN LONGER RANGE MODELS IN PAST MODEL RUNS...BUT AS WE GET
CLOSER TO THIS EVENT...MORE REALISTIC TEMPS WILL BE SHOWN.
&&
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
NEAR TERM: WIDESPREAD IFR WILL CONTINUE THROUGH AT LEAST 13Z-14Z.
WHILE FOG MAY LIFT SOMEWHAT TOWARD DAYBREAK, RAIN ASSOCIATED WITH
A COLD FRONT WILL KEEP CEILINGS IN THE IFR CATEGORY INTO MID-
MORNING. CONDITIONS WILL GRADUALLY IMPROVE THEREAFTER, WITH ALL
SITES REACHING VFR STATUS 18Z-20Z.
SHORT TO LONG TERM: VFR XPCTD...XCPT BRIEF MVFR CONDITIONS
POSSIBLE WITH SN SHWRS ACROSS NRN TAF SITES JUST AHEAD AND DURG
THE PASSAGE OF AN ARCTIC COLD FRONT LATE WED NGT AND THU MORN.
&&
.MARINE...
NEAR TERM: SCA REMAINS IN EFFECT TODAY INTO TONIGHT. A COLD FRONT
WILL MOVE ACROSS THE WATERS LATE THIS MORNING, TURNING SOUTHWEST
WINDS 15 TO 20 KT TO THE NORTHWEST AND INCREASING THEM TO 20 TO 30
KT. THE WINDS WILL SUBSIDE LATER TONIGHT ONCE THE INITIAL COLD
ADVECTION HAS PASSED.
SHORT TO LONG TERM: INITIALLY NO HDLNS TUE INTO WED MORN...THEN
WINDS AND SEAS APCHG AND REACHING SCA CONDITIONS FOR WED AFTN INTO
THUS MORN AHEAD TO JUST BEHIND THE ARCTIC COLD FRONT. CONDITIONS LOWER
BLO SCA CONDITIONS LATER THU INTO THU NGT AND CONT INTO FRI. KEPT
CLOSE TO FCST WW3 GUIDANCE FOR WV HTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR MEZ011-
015>017-029>032.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...HASTINGS
SHORT TERM...VJN
LONG TERM...VJN
AVIATION...HASTINGS
MARINE...HASTINGS/VJN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
521 AM EST MON JAN 14 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION BY AFTERNOON. MUCH COLDER
TEMPERATURES ARE EXPECTED BEHIND THE FRONT FOR TONIGHT AND
TUESDAY. AFTER A BRIEF RESPITE WEDNESDAY...AN ARCTIC FRONT WILL
CROSS THE REGION THURSDAY AND BRING BITTERLY COLD AIR FOR LATE
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
520 AM UPDATE...AS MENTIONED IN THE PREVIOUS DISCUSSION...RAIN
SHOWERS HAVE INDEED BEGUN MOVING INTO CENTRAL AND SOUTHERN
PORTIONS OF THE FORECAST AREA. HAVE INCREASED POPS TO LIKELY IN
THESE AREAS. NO OTHER CHANGES NEEDED.
PREVIOUS DISCUSSION...WIDESPREAD FOG WILL CONTINUE THROUGH THE
EARLY MORNING HOURS AS MOIST SOUTHWEST FLOW STREAMS INTO THE
FORECAST AREA AHEAD OF AN APPROACHING COLD FRONT. WITH VISIBILITY
STILL AT OR BELOW ONE HALF MILE, THE DENSE FOG ADVISORY REMAINS IN
PLACE UNTIL 8 AM FOR DOWNEAST AREAS. UPSTREAM RADARS SHOW RAIN
ASSOCIATED WITH THE FRONT CURRENTLY MOVING INTO NEW YORK. THIS
PRECIPITATION WILL CONTINUE TO PUSH EASTWARD ALONG WITH THE FRONT,
ENTERING NORTHWESTERN MAINE BY AROUND DAYBREAK. THE FRONT WILL
CROSS THE AREA DURING THE MORNING HOURS, MOVING OFFSHORE BY EARLY
AFTERNOON. THEREFORE EXPECT THE RAIN WILL QUICKLY COME TO AN END
SHORTLY AFTER NOON. WHILE THE BULK OF THE PRECIPITATION WILL BE
OVER NORTHERN PORTIONS OF THE FORECAST AREA, HAVE NOTED THAT SOME
OF THE LATEST GUIDANCE, INCLUDING THE 3KM HRRR MODEL, INDICATES
THAT THE RAIN WILL HOLD TOGETHER OVER DOWNEAST MAINE AS WELL. HAVE
THEREFORE BUMPED UP POPS THERE A BIT THROUGH MID-MORNING, BUT THEY
MAY HAVE TO BE INCREASED LATER AS TRENDS BECOME ESTABLISHED.
TEMPERATURES WILL RISE SLIGHTLY THIS MORNING WITH HIGHS RANGING
FROM THE LOWER 40S IN THE NORTH AND WEST TO MID AND UPPER 40S
DOWNEAST. ONCE THE FRONT COMES THROUGH, TEMPERATURES WILL QUICKLY
DROP UNDER BRISK NORTHWEST WINDS.
HIGH PRESSURE WILL SLOWLY BUILD OVER THE REGION TONIGHT. EXPECT
CLEARING SKIES AND DECREASING WINDS. ALTHOUGH OVERNIGHT TEMPS WILL
REMAIN ABOVE NORMAL, IT WILL BE MUCH COLDER THAN READINGS OVER THE
PAST COUPLE OF NIGHTS. LOWS WILL RANGE FROM THE SINGLE DIGITS IN THE
NORTH TO THE UPPER TEENS DOWNEAST. COASTAL AREAS WILL REMAIN IN THE
LOWER 20S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
FAIR AND COLDER CONDITIONS IS XPCTD TUE INTO TUE NGT AS SEMI-
ARCTIC SFC HI PRES CROSSES THE REGION. RETURN SRLY FLOW WILL OCCUR
ON WED BEHIND THIS HI AS IT MOVES INTO THE MARITIMES. IN THE MEANTIME...
A FLAT S/WV TRACKING ENE FROM SE NEW ENG S OF THE GULF OF ME WILL
BRING DOWNEAST PTNS OF THE FA INCREASING CLDS WED WITH A CHC OF LGT
RN/SN LATE WED INTO WED EVE ALG THE COAST AND MSLY OVR THE ADJACENT
COASTAL WATERS. IMMEDIATELY FOLLOWING THIS SYSTEM....A STRONG
ARCTIC FRONT WILL APCH WRN PTNS OF THE FA LATE WED NGT WITH SOME
CLDNSS AND A CHC OF SN SHWRS. TEMPS WILL BE A LITTLE MILDER ON
WED AND WED NGT WITH THE RETURN SRLY FLOW THAN TUE AND TUE NGT
WHICH WILL FEATURE NEAR SEASONAL TEMPS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
LONGER RANGE MODELS GENERALLY AGREE WITH MINOR TMG DIFFERENCES THAT
THE ARCTIC FRONT WILL CROSS THE REGION THU MORN...WITH MOST OF
SCT SN SHWRS OVR NW AND FAR NE PTNS OF THE REGION DURING THE
PASSAGE OF THE FRONT. MUCH COLDER TEMPS FOLLOW FOR THU NGT THRU
FRI NGT...WITH HI TEMPS WE SHOW FRI ACROSS THE REGION LIKELY
OPTIMISTIC. HI CLDS COULD BEGIN INCREASING ACROSS OUR REGION FROM
AN ADVCG S/WV FROM THE GREAT LKS AS EARLY AS LATE FRI NGT...BUT
WILL LIKELY HOLD OFF UNTIL SAT.
THE 00Z DTMNSTC GFS AND ECMWF CAME INTO BETTER AGREEMENT WITH THE
TMG OF THE GREAT LKS S/WV...BRINGING OVRRNG SNFL TO THE FA...SPCLY
NRN PTNS SAT NGT INTO SUN. OF THE TWO MODELS...THE GFS ACTUALLY
BRINGS SIG QPF ACROSS THE N HLF OF THE REGION WITH THIS SYSTEM AS
THE SFC TRACKS OVR OR JUST N OF THE FA...WITH LESSER AMTS SHOWN BY
THE ECMWF. FOR NOW...WE WILL INCREASE POPS TO HI CHC FOR STRATIFORM
SN UP TO 50 PERCENT FOR THE N....WITH LESSER POPS CNTRL AND DOWNEAST
AREAS. ANY STEADY SN SHOULD WIND DOWN AS SN SHWRS SUN AFTN AND SUN
NGT BEHIND THIS LOW AS IT MOVES INTO THE CAN MARITIMES...WITH
POTENTIALLY ANOTHER SHOT OF BITTERLY COLD ARCTIC AIR ADVCTG INTO
THE REGION BY LATE SUN NGT INTO MON. WE DO NOT INDICATE THE
POTENTIAL MAGNITUDE OF THIS AIR MASS WITH REGARD TO TEMPS SUN
NGT ATTM DUE TO UNCERTAINTY DUE TO PREVIOUS TMG DIFFERENCES
BETWEEN LONGER RANGE MODELS IN PAST MODEL RUNS...BUT AS WE GET
CLOSER TO THIS EVENT...MORE REALISTIC TEMPS WILL BE SHOWN.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
NEAR TERM: WIDESPREAD IFR WILL CONTINUE THROUGH AT LEAST 13Z-14Z.
WHILE FOG MAY LIFT SOMEWHAT TOWARD DAYBREAK, RAIN ASSOCIATED WITH
A COLD FRONT WILL KEEP CEILINGS IN THE IFR CATEGORY INTO MID-
MORNING. CONDITIONS WILL GRADUALLY IMPROVE THEREAFTER, WITH ALL
SITES REACHING VFR STATUS 18Z-20Z.
SHORT TO LONG TERM: VFR XPCTD...XCPT BRIEF MVFR CONDITIONS
POSSIBLE WITH SN SHWRS ACROSS NRN TAF SITES JUST AHEAD AND DURG
THE PASSAGE OF AN ARCTIC COLD FRONT LATE WED NGT AND THU MORN.
&&
.MARINE...
NEAR TERM: SCA REMAINS IN EFFECT TODAY INTO TONIGHT. A COLD FRONT
WILL MOVE ACROSS THE WATERS LATE THIS MORNING, TURNING SOUTHWEST
WINDS 15 TO 20 KT TO THE NORTHWEST AND INCREASING THEM TO 20 TO 30
KT. THE WINDS WILL SUBSIDE LATER TONIGHT ONCE THE INITIAL COLD
ADVECTION HAS PASSED.
SHORT TO LONG TERM: INITIALLY NO HDLNS TUE INTO WED MORN...THEN
WINDS AND SEAS APCHG AND REACHING SCA CONDITIONS FOR WED AFTN INTO
THUS MORN AHEAD TO JUST BEHIND THE ARCTIC COLD FRONT. CONDITIONS LOWER
BLO SCA CONDITIONS LATER THU INTO THU NGT AND CONT INTO FRI. KEPT
CLOSE TO FCST WW3 GUIDANCE FOR WV HTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR MEZ011-
015>017-029>032.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...HASTINGS
SHORT TERM...VJN
LONG TERM...VJN
AVIATION...HASTINGS
MARINE...HASTINGS/VJN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
652 AM EST MON JAN 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM EST MON JAN 14 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
EXTENDING FROM HUDSON BAY THROUGH THE NRN PLAINS INTO THE SW CONUS.
THE SHORTWAVE TROUGH THAT BROUGHT -SN/FLURRIES TO UPPER MI AND
HELPED ENHANCED THE LES INTO THE WEST HAD LIFTED OFF TO THE
NORTHEAST TOWARD QUEBEC. IN ITS WAKE...SHRTWV RIDGING WITH QVECTOR
DIV AND SUBSIDENCE HAS HELPED LIMIT LES INTENSITY OVERNIGHT.
UPSTREAM...ONLY A WEAK SHRTWV WAS NOTED OVER NEBRASKA. AT THE
SFC...A RIDGE EXTENDED FROM SASK THROUGH THE NRN PLAINS INTO THE MID
MS VALLEY RESULTING IN W TO WNW FLOW THROUGH THE NRN GREAT LAKES.
THE LINGERING LAKE INDUCED TROUGH HAS KEPT THE FOCUS OF LES OVER THE
KEWEENAW AND FOR LOCATIONS EAST OF P53.
INSTABILITY FOR LES WILL REMAIN FAVORABLE WITH 850 MB TEMPS NEAR
-19C PRODUCING LAKE INDUCED CAPES IN THE 400-500 J/KG RANGE. THE DGZ
WILL ALSO REMAIN IN THE CONVECTIVE LAYER...LEADING TO HIGH
SNOW/WATER RATIOS IN THE 25/1 TO 30/1 RANGE. UPSTREAM LOW LEVEL
MOISTURE OVER NRN MN WILL HELP MAINTAIN LES ACROSS WRN LAKE
SUPERIOR.
MODELS WERE CONSISTENT IN SUGGESTING THAT LOW LEVEL WINDS WILL
SLOWLY BACK. AS A RESULT...THE LES INTO THE ERN CWA COULD PRODUCE AN
ADDITIONAL 1 TO 3 INCHES BEFORE THE BANDS GRADUALLY SHIFT TOWARD THE
SHORELINE AND MOVE OUT OF THE AREA THIS AFTERNOON. OVER THE WEST...
THE HIGHER RES MODELS SUGGEST THAT THE STRONGEST LES BAND(S) MAINLY
NEAR THE SHORELINE OF ONTONAGON COUNTY TOWARD TWIN LAKES THIS
MORNING WOULD GRADUALLY SHIFT THROUGH NRN HOUGHTON COUNTY TODAY AND
EVENTUALLY TO CMX-P59 TONIGHT. THERE IS LOWER CONFIDENCE WITH THE
SNOWFALL RATES AND AMOUNT OF TIME IT WILL LINGER OVER ANY GIVEN
AREA. THE POTENTIAL REMAINS FOR LOCAL AMOUNTS IN THE 4 TO 8 INCH
RANGE BOTH TODAY AND TONIGHT AS IT LIFTS THROUGH THESE AREAS.
SO...THE LES WARNING WILL CONTINUE AT LEAST UNTIL 12Z/TUE.
OVER THE REST OF THE CWA...EXPECT MAINLY JUST A FEW FLURRIES OVER
THE NORTH OUTSIDE OF THE MAIN LES AREA. EVEN WITH MORE SUNSHINE
TODAY OVER THE SOUTH...TEMPERATURES WILL REMAIN AT OR BELOW NORMAL
FROM 12 TO 17 WEST AND IN THE LOWER 20S EAST. THERE MAY ALSO BE
ENOUGH CLEARING TONIGHT INLAND WITH LIGHT WSW WINDS AS THE RIDGE
BUILDS TOWARD THE REGION TO ALLOW TEMPS TO DIP TO AROUND ZERO.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 535 AM EST MON JAN 14 2013
TUESDAY LOOKS TO BE ONE OF THE FEW BREAKS FROM SNOW FOR MUCH OF THE
LAND CWA...AS WINDS BACK TO THE WEST-SOUTHWEST AHEAD OF AN
APPROACHING SHORTWAVE AND ASSOCIATED COLD FRONT. THIS WILL PUSH
WHAT IS LEFT OF THE BANDS CURRENTLY OVER NORTHERN HOUGHTON AND
KEWEENAW COUNTIES ALONG THE WESTERN SHORELINE DURING THE MORNING
AND THEN OFFSHORE DURING THE AFTERNOON. THE BANDS WILL ALSO BE
DIMINISHING IN INTENSITY DUE TO INCREASING H850 TEMPS.
ELSEWHERE...LOOKS TO BE A FAIRLY NICE DAY WITH ONLY A FEW MID LEVEL
CLOUDS MOVING THROUGH.
HEADING INTO TUESDAY NIGHT...LOOKS LIKE IT COULD BE GUSTY ACROSS
MUCH OF UPPER MICHIGAN AHEAD OF THE COLD FRONT. GALES OVER LAKE
SUPERIOR STILL LOOK LIKELY...SO WILL CONTINUE GALE WATCH. OVER
LAND...INVERSION WILL KEEP MUCH OF THE STRONG 50-60KT LOW LEVEL JET
ALOFT. BUT LATE IN THE NIGHT...THINK IT WILL GET A LITTLE GUSTY AS
THE 10-14MB 6HR PRESSURE FALLS MOVE ACROSS THE CWA. STRONGEST WINDS
WILL LIKELY END UP IN THE SOUTHWEST WIND DOWNSLOPE AREAS NEAR LAKE
SUPERIOR...MAYBE APPROACHING 35-45MPH...WHILE THE REST OF THE AREA
WILL SEE A FEW HOUR PERIOD OF 25-35MPH GUSTS.
THERE IS MUCH BETTER AGREEMENT WITH THE SHORTWAVE AND ASSOCIATED
COLD FRONT THAT MOVES THROUGH LATE TUESDAY NIGHT INTO WEDNESDAY
MORNING. DUE TO THIS...HAVE DELAYED THE START OF THE SNOW INTO THE
OVERNIGHT HOURS. BEST H500 HEIGHT FALLS STAY OVER NORTHERN LAKE
SUPERIOR AND SOUTHERN ONTARIO...BUT DECENT H850-500 Q-VECTOR
CONVERGENCE MOVES OVER THE NORTHERN HALF OF THE CWA. WILL CONTINUE
TO HIGHLIGHT THE HIGHEST POPS OVER THE NORTH HALF OF THE CWA...WITH
CHANCES ELSEWHERE. WITH IT MOVING THROUGH FAIRLY QUICKLY...DON/T
THINK THERE WILL BE TOO MUCH SNOW ACCUMULATION...WITH THE HIGHEST
AMOUNTS OVER THE KEWEENAW AND LUCE COUNTY WHERE THERE COULD BE SOME
ENHANCEMENT OFF LAKE MICHIGAN. THE LEAST AMOUNTS WILL LIKELY BE
OVER THE CENTRAL CWA...WHERE DRY LOW LEVEL AIR WILL LEAD TO SOME
INITIAL EVAPORATION OF THE SNOW. THERE IS A SLIGHT DELAY IN THE
COLD AIR SURGING IN BEHIND THE FRONT...SO AFTER SNOW DIMINISHES ON
WEDNESDAY MORNING AND EARLY AFTERNOON...PROBABLY WONT BE MUCH GOING
ON LAKE EFFECT WISE UNTIL THE COLDER ARRIVES LATE WEDNESDAY
AFTERNOON AND WEDNESDAY NIGHT.
BEHIND THE FRONT...PERSISTENT LAKE EFFECT SNOW IS EXPECTED WEDNESDAY
NIGHT THROUGH THURSDAY NIGHT FOR WEST TO NORTHWEST FLOW FAVORED
LOCATIONS. THE AREA WILL BE BETWEEN THE SURFACE LOW ROTATING OVER
HUDSON BAY AND A HIGH PRESSURE IN THE PLAINS STATES. H850 TEMPS
FALLING TO AROUND -24C BEHIND THE FRONT SHOULD PRODUCE SIGNIFICANT
LAKE INSTABILITY DUE TO LAKE SUPERIOR WATER TEMPS AROUND 3C. SINCE
MODELS ARE SHOWING THE INVERSION AROUND 5KFT TO BE FAIRLY
WEAK...LAKE INDUCED EQL LEVELS RISE TO 9-10KFT AND CAPE VALUES
APPROACH 900 J/KG. THESE ARE FAIRLY IMPRESSIVE VALUES...BUT THE
CONCERN WITH SIGNIFICANT SNOWFALL COMES WITH THE BEST MOISTURE
FOCUSED IN THE 2-5KFT RANGE. WITH THE COLD AIR...THE CONVECTIVE
PORTION OF THE LAKE EFFECT SHOULD BE ABOVE THE DGZ AND LEAD TO
MORE COLUMN/PLATE SNOW TYPE...AT LEAST FOR WEDNESDAY NIGHT AND
THURSDAY. THIS WILL LEAD TO LOWER SNOW RATIOS THAN WHAT HAVE BEEN
SEEN OVER THE LAST DAY AND GENERALLY IN THE 15-20 TO 1 RANGE. THE
PERSISTENT NATURE OF THE SNOW DURING THIS PERIOD WILL LIKELY
PRODUCE DECENT LAKE EFFECT SNOW ACCUMULATIONS IN THE FAVORED
LOCATIONS AND WILL CONTINUE TO MENTION PERIODS OF MODERATE SNOW IN
THE HWO. SINCE THE MODELS HAVE BEEN CONSISTENT ON THIS PERIOD OF
LES...WILL MAKE THE JUMP UP TO DEFINITE POPS IN THE WNW TO NW
FAVORED AREAS. TIMING OF SHORTWAVES AND ASSOCIATED POCKETS OF DEEPER
MOISTURE ARE DIFFICULT TO LOCATE/TIME IN NORTHWEST FLOW...BUT THEY
COULD LEAD TO PERIODS OF HEAVY SNOW. THIS WOULD ESPECIALLY BE
TRUE ON THURSDAY AFTERNOON/NIGHT WHEN TEMPS WARM SLIGHTLY TO RAISE
THE DGZ FROM THE SURFACE.
00Z GFS/ECMWF HAVE GOOD CONSISTENCY WITH SHORTWAVE AND CLIPPER
SYSTEM AFFECTING THE AREA ON FRIDAY. CONFIDENCE IN TIMING/LOCATION
STILL IS LOW...BUT THE LATEST TRENDS SUGGEST A BETTER H850 WAA
FOCUS ACROSS THE CWA FOR FRIDAY. THIS WOULD LEAD TO BETTER SNOWFALL
CHANCES /1-2IN OF ACCUM OVER MUCH OF THE CWA/ THAN THE LOW END
CHANCES THAT ARE CURRENTLY IN PLACE. IF MODELS CONTINUE TO SHOW
THIS IDEA...WILL NEED TO BUMP UP POPS.
NORTHWEST FLOW ALOFT WILL CONTINUE INTO THE WEEKEND AS A
UPPER RIDGE BUILDS OVER THE PACIFIC NORTHWEST. BUT MODELS ARE REALLY
STARTING TO DIFFER IN THE UPPER LOW SPINNING EAST OF HUDSON BAY AND
WHAT HAPPENS TO IT THROUGH THE WEEKEND. NO MATTER THE SOLUTION...IT
APPEARS THE AREA WILL STILL BE UNDER THE INFLUENCE OF THE UPPER
TROUGH BUT THERE APPEARS TO BE STRONGER SHORTWAVES DISRUPTING THE
TROUGH SOME. THESE DISRUPTIONS PRODUCES MORE UNCERTAINTY IN THE LOW
TRACK FORECAST...WHICH MAKES THE LOW LEVEL WIND FIELDS HIGHLY
VARIABLE FOR PINNING DOWN LAKE EFFECT AREAS IN ADDITION TO
SYNOPTIC SNOW. WILL FOLLOW A GENERAL MODEL CONSENSUS...WHICH
WILL CONTINUE TO FOCUS THE HIGHEST CHANCE POPS NEAR LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 638 AM EST MON JAN 14 2013
CMX...EXPECT PREDOMINANT IFR CONDITIONS THRU TODAY WITH PERSISTENT/
UPSLOPE WNW FLOW AND SUFFICIENT INSTABILITY FOR LES. THE BEST CHC
FOR LIFR WX WL BE 15Z-21Z TODAY...WHEN AXIS OF ENHANCED LOW LEVEL
CONVERGENCE ASSOCIATED WITH SLOWLY BACKING LARGER SCALE FLOW WL
SHIFT OVHD. HOWEVER...CONFIDENCE IN THE TIMING AND STRENGTH OF THE
BAND IS MARGINAL. AS THE FLOW BACKS MORE TO THE WSW...THE HEAVIER
SHSN SHOULD SHIFT TO THE N OF THE SITE AND ALLOW A RETURN OF
PREDOMINANT MVFR CONDITIONS AND LIGHTER -SHSN.
IWD/SAW...ALTHOUGH SOME MVFR CONDITIONS MIGHT IMPACT THESE SITES
EARLY IN THE PERIOD...A SLOWLY BACKING LLVL FLOW TOWARD THE WSW WL
ADVECT DRIER AIR OVHD AND ALLOW FOR MAINLY VFR WX.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EST MON JAN 14 2013
NORTHWEST WINDS WILL GRADUALLY BACK TODAY AND TONIGHT...WITH MOST
LOCATIONS SEEING WINDS IN THE 15-25KT RANGE. AS A COLD FRONT
APPROACHES THE AREA ON TUESDAY AND TUESDAY EVENING...SOUTHWEST
WINDS WILL INCREASE TO GALES OF 35-45KTS FOR TUESDAY NIGHT. THEN AS
THE FRONT MOVES THROUGH ON WEDNESDAY MORNING...THE WINDS ARE
EXPECTED TO VEER TO THE NORTHWEST AND STILL PRODUCE GALES TO 40KTS.
THE TIMING OF THE GALE WATCH LOOKS TO BE IN GOOD SHAPE AND WILL
KEEP IT IN PLACE.
NORTHWEST FLOW WILL REMAIN WEDNESDAY NIGHT INTO THURSDAY
NIGHT...WITH WINDS GENERALLY IN THE 15-30KT RANGE WITH A FEW GUSTS
TO 35KTS ON THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ001-003.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ002.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ006-007.
LAKE SUPERIOR...
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING FOR
LSZ265>267.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY AFTERNOON
FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
536 AM EST MON JAN 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM EST MON JAN 14 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
EXTENDING FROM HUDSON BAY THROUGH THE NRN PLAINS INTO THE SW CONUS.
THE SHORTWAVE TROUGH THAT BROUGHT -SN/FLURRIES TO UPPER MI AND
HELPED ENHANCED THE LES INTO THE WEST HAD LIFTED OFF TO THE
NORTHEAST TOWARD QUEBEC. IN ITS WAKE...SHRTWV RIDGING WITH QVECTOR
DIV AND SUBSIDENCE HAS HELPED LIMIT LES INTENSITY OVERNIGHT.
UPSTREAM...ONLY A WEAK SHRTWV WAS NOTED OVER NEBRASKA. AT THE
SFC...A RIDGE EXTENDED FROM SASK THROUGH THE NRN PLAINS INTO THE MID
MS VALLEY RESULTING IN W TO WNW FLOW THROUGH THE NRN GREAT LAKES.
THE LINGERING LAKE INDUCED TROUGH HAS KEPT THE FOCUS OF LES OVER THE
KEWEENAW AND FOR LOCATIONS EAST OF P53.
INSTABILITY FOR LES WILL REMAIN FAVORABLE WITH 850 MB TEMPS NEAR
-19C PRODUCING LAKE INDUCED CAPES IN THE 400-500 J/KG RANGE. THE DGZ
WILL ALSO REMAIN IN THE CONVECTIVE LAYER...LEADING TO HIGH
SNOW/WATER RATIOS IN THE 25/1 TO 30/1 RANGE. UPSTREAM LOW LEVEL
MOISTURE OVER NRN MN WILL HELP MAINTAIN LES ACROSS WRN LAKE
SUPERIOR.
MODELS WERE CONSISTENT IN SUGGESTING THAT LOW LEVEL WINDS WILL
SLOWLY BACK. AS A RESULT...THE LES INTO THE ERN CWA COULD PRODUCE AN
ADDITIONAL 1 TO 3 INCHES BEFORE THE BANDS GRADUALLY SHIFT TOWARD THE
SHORELINE AND MOVE OUT OF THE AREA THIS AFTERNOON. OVER THE WEST...
THE HIGHER RES MODELS SUGGEST THAT THE STRONGEST LES BAND(S) MAINLY
NEAR THE SHORELINE OF ONTONAGON COUNTY TOWARD TWIN LAKES THIS
MORNING WOULD GRADUALLY SHIFT THROUGH NRN HOUGHTON COUNTY TODAY AND
EVENTUALLY TO CMX-P59 TONIGHT. THERE IS LOWER CONFIDENCE WITH THE
SNOWFALL RATES AND AMOUNT OF TIME IT WILL LINGER OVER ANY GIVEN
AREA. THE POTENTIAL REMAINS FOR LOCAL AMOUNTS IN THE 4 TO 8 INCH
RANGE BOTH TODAY AND TONIGHT AS IT LIFTS THROUGH THESE AREAS.
SO...THE LES WARNING WILL CONTINUE AT LEAST UNTIL 12Z/TUE.
OVER THE REST OF THE CWA...EXPECT MAINLY JUST A FEW FLURRIES OVER
THE NORTH OUTSIDE OF THE MAIN LES AREA. EVEN WITH MORE SUNSHINE
TODAY OVER THE SOUTH...TEMPERATURES WILL REMAIN AT OR BELOW NORMAL
FROM 12 TO 17 WEST AND IN THE LOWER 20S EAST. THERE MAY ALSO BE
ENOUGH CLEARING TONIGHT INLAND WITH LIGHT WSW WINDS AS THE RIDGE
BUILDS TOWARD THE REGION TO ALLOW TEMPS TO DIP TO AROUND ZERO.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 535 AM EST MON JAN 14 2013
TUESDAY LOOKS TO BE ONE OF THE FEW BREAKS FROM SNOW FOR MUCH OF THE
LAND CWA...AS WINDS BACK TO THE WEST-SOUTHWEST AHEAD OF AN
APPROACHING SHORTWAVE AND ASSOCIATED COLD FRONT. THIS WILL PUSH
WHAT IS LEFT OF THE BANDS CURRENTLY OVER NORTHERN HOUGHTON AND
KEWEENAW COUNTIES ALONG THE WESTERN SHORELINE DURING THE MORNING
AND THEN OFFSHORE DURING THE AFTERNOON. THE BANDS WILL ALSO BE
DIMINISHING IN INTENSITY DUE TO INCREASING H850 TEMPS.
ELSEWHERE...LOOKS TO BE A FAIRLY NICE DAY WITH ONLY A FEW MID LEVEL
CLOUDS MOVING THROUGH.
HEADING INTO TUESDAY NIGHT...LOOKS LIKE IT COULD BE GUSTY ACROSS
MUCH OF UPPER MICHIGAN AHEAD OF THE COLD FRONT. GALES OVER LAKE
SUPERIOR STILL LOOK LIKELY...SO WILL CONTINUE GALE WATCH. OVER
LAND...INVERSION WILL KEEP MUCH OF THE STRONG 50-60KT LOW LEVEL JET
ALOFT. BUT LATE IN THE NIGHT...THINK IT WILL GET A LITTLE GUSTY AS
THE 10-14MB 6HR PRESSURE FALLS MOVE ACROSS THE CWA. STRONGEST WINDS
WILL LIKELY END UP IN THE SOUTHWEST WIND DOWNSLOPE AREAS NEAR LAKE
SUPERIOR...MAYBE APPROACHING 35-45MPH...WHILE THE REST OF THE AREA
WILL SEE A FEW HOUR PERIOD OF 25-35MPH GUSTS.
THERE IS MUCH BETTER AGREEMENT WITH THE SHORTWAVE AND ASSOCIATED
COLD FRONT THAT MOVES THROUGH LATE TUESDAY NIGHT INTO WEDNESDAY
MORNING. DUE TO THIS...HAVE DELAYED THE START OF THE SNOW INTO THE
OVERNIGHT HOURS. BEST H500 HEIGHT FALLS STAY OVER NORTHERN LAKE
SUPERIOR AND SOUTHERN ONTARIO...BUT DECENT H850-500 Q-VECTOR
CONVERGENCE MOVES OVER THE NORTHERN HALF OF THE CWA. WILL CONTINUE
TO HIGHLIGHT THE HIGHEST POPS OVER THE NORTH HALF OF THE CWA...WITH
CHANCES ELSEWHERE. WITH IT MOVING THROUGH FAIRLY QUICKLY...DON/T
THINK THERE WILL BE TOO MUCH SNOW ACCUMULATION...WITH THE HIGHEST
AMOUNTS OVER THE KEWEENAW AND LUCE COUNTY WHERE THERE COULD BE SOME
ENHANCEMENT OFF LAKE MICHIGAN. THE LEAST AMOUNTS WILL LIKELY BE
OVER THE CENTRAL CWA...WHERE DRY LOW LEVEL AIR WILL LEAD TO SOME
INITIAL EVAPORATION OF THE SNOW. THERE IS A SLIGHT DELAY IN THE
COLD AIR SURGING IN BEHIND THE FRONT...SO AFTER SNOW DIMINISHES ON
WEDNESDAY MORNING AND EARLY AFTERNOON...PROBABLY WONT BE MUCH GOING
ON LAKE EFFECT WISE UNTIL THE COLDER ARRIVES LATE WEDNESDAY
AFTERNOON AND WEDNESDAY NIGHT.
BEHIND THE FRONT...PERSISTENT LAKE EFFECT SNOW IS EXPECTED WEDNESDAY
NIGHT THROUGH THURSDAY NIGHT FOR WEST TO NORTHWEST FLOW FAVORED
LOCATIONS. THE AREA WILL BE BETWEEN THE SURFACE LOW ROTATING OVER
HUDSON BAY AND A HIGH PRESSURE IN THE PLAINS STATES. H850 TEMPS
FALLING TO AROUND -24C BEHIND THE FRONT SHOULD PRODUCE SIGNIFICANT
LAKE INSTABILITY DUE TO LAKE SUPERIOR WATER TEMPS AROUND 3C. SINCE
MODELS ARE SHOWING THE INVERSION AROUND 5KFT TO BE FAIRLY
WEAK...LAKE INDUCED EQL LEVELS RISE TO 9-10KFT AND CAPE VALUES
APPROACH 900 J/KG. THESE ARE FAIRLY IMPRESSIVE VALUES...BUT THE
CONCERN WITH SIGNIFICANT SNOWFALL COMES WITH THE BEST MOISTURE
FOCUSED IN THE 2-5KFT RANGE. WITH THE COLD AIR...THE CONVECTIVE
PORTION OF THE LAKE EFFECT SHOULD BE ABOVE THE DGZ AND LEAD TO
MORE COLUMN/PLATE SNOW TYPE...AT LEAST FOR WEDNESDAY NIGHT AND
THURSDAY. THIS WILL LEAD TO LOWER SNOW RATIOS THAN WHAT HAVE BEEN
SEEN OVER THE LAST DAY AND GENERALLY IN THE 15-20 TO 1 RANGE. THE
PERSISTENT NATURE OF THE SNOW DURING THIS PERIOD WILL LIKELY
PRODUCE DECENT LAKE EFFECT SNOW ACCUMULATIONS IN THE FAVORED
LOCATIONS AND WILL CONTINUE TO MENTION PERIODS OF MODERATE SNOW IN
THE HWO. SINCE THE MODELS HAVE BEEN CONSISTENT ON THIS PERIOD OF
LES...WILL MAKE THE JUMP UP TO DEFINITE POPS IN THE WNW TO NW
FAVORED AREAS. TIMING OF SHORTWAVES AND ASSOCIATED POCKETS OF DEEPER
MOISTURE ARE DIFFICULT TO LOCATE/TIME IN NORTHWEST FLOW...BUT THEY
COULD LEAD TO PERIODS OF HEAVY SNOW. THIS WOULD ESPECIALLY BE
TRUE ON THURSDAY AFTERNOON/NIGHT WHEN TEMPS WARM SLIGHTLY TO RAISE
THE DGZ FROM THE SURFACE.
00Z GFS/ECMWF HAVE GOOD CONSISTENCY WITH SHORTWAVE AND CLIPPER
SYSTEM AFFECTING THE AREA ON FRIDAY. CONFIDENCE IN TIMING/LOCATION
STILL IS LOW...BUT THE LATEST TRENDS SUGGEST A BETTER H850 WAA
FOCUS ACROSS THE CWA FOR FRIDAY. THIS WOULD LEAD TO BETTER SNOWFALL
CHANCES /1-2IN OF ACCUM OVER MUCH OF THE CWA/ THAN THE LOW END
CHANCES THAT ARE CURRENTLY IN PLACE. IF MODELS CONTINUE TO SHOW
THIS IDEA...WILL NEED TO BUMP UP POPS.
NORTHWEST FLOW ALOFT WILL CONTINUE INTO THE WEEKEND AS A
UPPER RIDGE BUILDS OVER THE PACIFIC NORTHWEST. BUT MODELS ARE REALLY
STARTING TO DIFFER IN THE UPPER LOW SPINNING EAST OF HUDSON BAY AND
WHAT HAPPENS TO IT THROUGH THE WEEKEND. NO MATTER THE SOLUTION...IT
APPEARS THE AREA WILL STILL BE UNDER THE INFLUENCE OF THE UPPER
TROUGH BUT THERE APPEARS TO BE STRONGER SHORTWAVES DISRUPTING THE
TROUGH SOME. THESE DISRUPTIONS PRODUCES MORE UNCERTAINTY IN THE LOW
TRACK FORECAST...WHICH MAKES THE LOW LEVEL WIND FIELDS HIGHLY
VARIABLE FOR PINNING DOWN LAKE EFFECT AREAS IN ADDITION TO
SYNOPTIC SNOW. WILL FOLLOW A GENERAL MODEL CONSENSUS...WHICH
WILL CONTINUE TO FOCUS THE HIGHEST CHANCE POPS NEAR LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1209 AM EST MON JAN 14 2013
CMX...EXPECT PREDOMINANT IFR CONDITIONS THRU TODAY WITH PERSISTENT/
UPSLOPE WNW FLOW AND SUFFICIENT INSTABILITY FOR LES. THE BEST CHC
FOR LIFR WX WL BE 12Z-18Z TODAY...WHEN AXIS OF ENHANCED LLVL CNVGC
ASSOCIATED WITH SLOWLY BACKING LARGER SCALE FLOW WL SHIFT OVHD. AS
THE FLOW BACKS MORE TO THE WSW...THE HEAVIER SHSN SHOULD SHIFT TO
THE N OF THE SITE AND ALLOW A RETURN OF PREDOMINANT MVFR CONDITIONS/
LIGHTER -SHSN.
IWD/SAW...ALTHOUGH SOME MVFR CONDITIONS MIGHT IMPACT THESE SITES
EARLY IN THE PERIOD...A SLOWLY BACKING LLVL FLOW TOWARD THE WSW WL
ADVECT DRIER AIR OVHD AND ALLOW A RETURN OF PREDOMINANT VFR WX.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EST MON JAN 14 2013
NORTHWEST WINDS WILL GRADUALLY BACK TODAY AND TONIGHT...WITH MOST
LOCATIONS SEEING WINDS IN THE 15-25KT RANGE. AS A COLD FRONT
APPROACHES THE AREA ON TUESDAY AND TUESDAY EVENING...SOUTHWEST
WINDS WILL INCREASE TO GALES OF 35-45KTS FOR TUESDAY NIGHT. THEN AS
THE FRONT MOVES THROUGH ON WEDNESDAY MORNING...THE WINDS ARE
EXPECTED TO VEER TO THE NORTHWEST AND STILL PRODUCE GALES TO 40KTS.
THE TIMING OF THE GALE WATCH LOOKS TO BE IN GOOD SHAPE AND WILL
KEEP IT IN PLACE.
NORTHWEST FLOW WILL REMAIN WEDNESDAY NIGHT INTO THURSDAY
NIGHT...WITH WINDS GENERALLY IN THE 15-30KT RANGE WITH A FEW GUSTS
TO 35KTS ON THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ001-003.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ002.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ006-007.
LAKE SUPERIOR...
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING FOR
LSZ265>267.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY AFTERNOON
FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1036 AM EST MON JAN 14 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PRODUCE UNSEASONABLY WARM CONDITIONS
INTO MID-WEEK. A COLD FRONT WILL MOVE SLOWLY THROUGH THE AREA
LATE WEDNESDAY. WEAK GULF COAST LOW PRESSURE MAY BRING A CHANCE OF
LIGHT RAIN TO THE REGION THURSDAY NIGHT OR FRIDAY. HIGH PRESSURE
WILL BUILD IN BEHIND THE COLD FRONT FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM MONDAY...HAVE ADJUSTED TEMPS UP A COUPLE OF DEGREES
FOR TODAY KEEPING MAX TEMPS IN THE MID TO UPPER 70S. THE
SOUTHWESTERLY WINDS WILL BACK A BIT PRODUCING MORE OF AN ON
SHORE FLOW THROUGH THE AFTERNOON. THIS WILL KEEP TEMPS COOLER
ALONG THE SHORE...MOVING INLAND AS WINDS PICK UP THROUGH THE
AFTERNOON. SEA FOG WILL ALSO HELP TO KEEP TEMPS COOLER ALONG THE
COAST.
PREVIOUS DISCUSSION...MODELS INDICATE THE MID TO UPPER LEVEL RIDGE TO
REMAIN ANCHORED JUST OFF THE SE U.S. COAST DURING THIS NEAR TERM
PERIOD. THIS WILL SLOW DOWN THE PROGRESSION OF THE BAROCLINIC ZONE
IE. THE SFC COLD FRONT...TOWARD THE SOUTHEAST. IN FACT... MODELS
ACTUALLY STALL THE COLD FRONT JUST NORTH AND WEST OF THE FA AS IT
BECOMES ORIENTED PARALLEL WITH THE FLOW ALOFT. THE DEEPEST
MOISTURE WILL REMAIN JUST OUTSIDE OF THE ILM CWA DURING THIS NEAR
TERM PERIOD...REMAINING WEST THROUGH NORTH OF THE FA. AMAZINGLY...
GFS/NAM/EUROPEAN/ETC. AGREE THAT THIS SCENARIO WILL PLAY OUT. NOW
WHAT THEY DO NOT AGREE IS THE THREAT OR PROBABILITY FOR PCPN. WITH
THE BEST LIFT REMAINING OUTSIDE OF THE ILM CWA DOMAIN...HAVE
INDICATED A LOW CHANCE OF POPS FOR THE NW PORTIONS OF THE FA FROM
THIS AFTERNOON THROUGH TONIGHT...ROUGHLY ALONG AND WEST OF THE
I-95 CORRIDOR. THE LATEST RUN OF THE HRRR MODEL ALSO INDICATES
THIS PCPN POSSIBILITY. HAVE STAYED AWAY FROM MENTIONING THUNDER
DUE TO THE LACK OF INSTABILITY ILLUSTRATED BY LATEST NAMBUFR
SOUNDINGS...IE. NO CAPE...LI`S STAY MAINLY POSITIVE. WILL LIKELY
HAVE A SOMEWHAT OF A SHARP CLOUD GRADIENT ACROSS THE FA WITH THE
IMMEDIATE COAST HAVING THE BEST POTENTIAL TO OBSERVE THE DAYS
INSOLATION. THEREFORE...HAVE RELIED ON THE WARMER MODEL MOS
GUIDANCE FOR BOTH TODAYS MAX AND TONIGHTS MIN TEMPS. THIS WILL
RESULT IN ADDITIONAL MAX TEMP RECORDS LIKELY BEING SET FOR 1 MORE
DAY. AND FINALLY...THE MID TO UPPER LEVEL CLOUD DECK ACROSS THE FA
HAS BEEN OPAQUE ENOUGH TO PREVENT WIDESPREAD RADIATIONAL TYPE
DENSE FOG. HOWEVER...SEA FOG IE. ADVECTION TYPE FOG...WILL
SPORADICALLY AFFECT THE IMMEDIATE COAST AS SFC WINDS SLIGHTLY BACK
TO THE SSW AND PUSH 60+ DEWPOINTS ACROSS SSTS IN THE 50S RESULTING
WITH SEA FOG BRIEFLY PUSHING ONSHORE AT TIMES.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 245 AM MONDAY...WEAK FRONT WILL BE STALLED IN OR JUST WEST
OF THE REGION FOR A MAJORITY OF THE PERIOD. PROXIMITY TO FRONT
WILL CREATE SIGNIFICANT TEMP GRADIENT ACROSS THE
REGION...PROVIDING PLENTY OF POTENTIAL FOR THE FORECAST TO GO
WRONG. SOME WEAK ISENTROPIC LIFT AND LOW LEVEL MOISTURE MAY
PRODUCE SOME PATCHY LIGHT RAIN AT TIMES. ALTHOUGH DRY MID AND
UPPER LEVELS WILL LIKELY KEEP MUCH OF THE AREA DRY FOR A MAJORITY
OF THE PERIOD. COMBINATION OF FRONT IN THE REGION AND LOW LEVEL
CLOUD COVER WILL TEMPER HIGHS ACROSS PORTIONS OF THE FORECAST AREA
BOTH DAYS. COASTAL SC ENDS UP WARMEST WITH A LITTLE LESS CLOUD
COVER AND SOUTHERLY FLOW INTO WED NIGHT. HIGHS WILL BE IN THE LOW
70S WITH LOWS IN THE UPPER 50S TO AROUND 60.
INLAND SC AND NC WILL HAVE BEST PRECIP CHANCES...THOUGH AT THIS
POINT LITTLE MORE THAN LOW CHANCE OR SLIGHT CHANCE APPEARS
WARRANTED. HIGH TEMP FORECAST WILL BE TRICKY IN THESE AREAS WITH
LOCATION OF FRONT...AND THE NORTHERLY FLOW BEHIND IT...LEADING TO A
SHARP GRADIENT SOMEWHERE IN THE FORECAST AREA. FOR NOW WILL GO WITH
HIGHS NEAR TO ABOVE CLIMO TUE AND ABOVE TO WELL ABOVE CLIMO WED.
HOWEVER A MORE EASTERLY POSITION OF THE FRONT WED...SOMETHING
GUIDANCE IS TRENDING AWAY FROM...WOULD RESULT IN COOLER TEMPS. LOWS
WILL CONTINUE TO RUN ABOVE CLIMO REGARDLESS OF FRONTAL POSITION
GIVEN PLENTY OF CLOUD COVER AND LIMITED COLD ADVECTION ON BACKSIDE
OF THE BOUNDARY.
FRONT IS PULLED OFF THE COAST WED NIGHT BY WEAK SURFACE LOW MOVING
INTO THE CANADIAN MARITIMES. LACK OF ANY MID LEVEL PUSH TRANSLATES
TO MINIMAL TEMP REDUCTION AS THE PERIOD ENDS. NORTH TO NORTHEAST
FLOW ACROSS THE AREA BY END OF PERIOD ONLY DROPS WED NIGHT LOWS A
FEW DEGREES.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 245 AM MONDAY...SOUTHERN STREAM SYSTEM EMERGING FROM THE
SOUTHWEST MID WEEK WILL BRING THE PERIODS BEST AND ONLY PRECIP
CHANCE THU NIGHT INTO FRI. DEEP SOUTHWEST FLOW AHEAD OF THE WAVE
AS IT CROSSES THE GULF COAST INCREASES MOISTURE OVER THE
SOUTHEAST THU. DIVERGENT PATTERN ALOFT THU NIGHT INTO FRI IS
ENHANCED BY 200MB JET STREAK APPROACHING 120 KT. RIGHT NOW THE
BIGGEST NEGATIVE FACTOR APPEARS TO BE THE TRACK OF THE MID LEVEL
FEATURE AND THE ASSOCIATED SURFACE WAVE. WEAK SURFACE LOW DEVELOPS
ALONG FRONT STALLED ACROSS NORTHERN GOMEX EARLY THU. THIS LOW
TRACKS NORTHEAST ALONG THE FRONT...PASSING OFF THE SOUTHEAST COAST.
THIS KEEPS NORTHEAST LOW LEVEL FLOW IN PLACE FOR THE DURATION OF
THE EVENT. BELOW 700MB OR SO FORECAST SOUNDINGS DEPICT A SATURATED
BUT VERY STABLE AIR MASS. SO WHILE MID AND UPPER LEVEL FORCING
WILL BE PRESENT IT APPEARS THE LOW LEVEL STABILITY WILL ULTIMATELY
WIN OUT. THUS HAVE GONE FOR LOWER POP AND MINIMAL QPF EARLY IN THE
PERIOD.
AS SURFACE AND MID LEVEL FEATURES MOVE OFF TO THE NORTHEAST HIGH
PRESSURE BUILDS IN UNDER DEVELOPING PROGRESSIVE MID LEVEL PATTERN.
THIS ALLOWS MUCH DRIER AND COOLER AIR TO SPREAD IN FROM THE WEST.
PINCHED GRADIENT ALONG THE COAST WILL KEEP NORTHEAST FLOW BRISK INTO
SAT MORNING...ESPECIALLY ALONG THE COAST. LATE IN THE PERIOD MEDIUM
RANGE GUIDANCE IS TRYING TO SHOW A WEAK COASTAL LOW DEVELOPING ON
REMAINS OF STALLED SURFACE BOUNDARY. GIVEN THE TIME RANGE AND
POTENTIAL FOR SIGNIFICANT CHANGES REGARDING THIS FEATURE WILL NOT
INTRODUCE A POP LATE IN THE PERIOD. TEMPS NEAR CLIMO THROUGH THE
PERIOD.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 12Z...LBT IS LIFR AND WILL LIKELY NOT REACH VFR UNTIL
14Z...PERHAPS EVEN AN HOUR LATER. THE OTHER TERMINALS APPEAR TO HAVE
ENOUGH SOUTHWEST FLOW TO MIX OUT A BIT EARLIER. STAGNANT SYNOPTIC
PATTERN WILL KEEP THE FRONT WEST OF THE REGION...WITH MAINLY THICK
HIGH CLOUDS IN AND OUT OF OUR WESTERN TERMINALS. ALONG THE
COAST...GOOD LOW LEVEL MOISTURE WILL GIVE US A CHANCE OF AN MVFR
CEILING IN AND OUT THROUGH EARLY AFTERNOON. SOUTHWEST FLOW WILL
CONTINUE THROUGH THE OVERNIGHT HOURS. IT APPEARS THE WINDS WILL BE
TOO STRONG TO SUPPORT FOG...BUT WILL REEVALUATE ON THE NEXT SET OF
TAFS.
EXTENDED OUTLOOK...POSSIBLE RESTRICTIONS IN ASSOCIATION WITH COLD
FRONT TUESDAY AND WEDNESDAY...MAINLY AT THE INLAND TERMINALS.
CHANCE FOR SHOWERS THURSDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM MONDAY...SFC PRESSURE PATTERN INDICATES THE WESTERN
ATLANTIC HIGH...CENTERED OFFSHORE FROM THE SE U.S. COAST...WILL
PRODUCE SSW THROUGH WSW WIND DIRECTIONS. THE SFC PG WILL SLIGHTLY
TIGHTEN AS THE SFC COLD FRONT APPROACHES FROM THE NW TODAY...
BEFORE STALLING BETWEEN DUCK NC SOUTHWEST TO PENSACOLA BEACH
FLORIDA TONIGHT. LOOK FOR WIND SPEEDS AT 5 TO 10 KT THIS
MORNING...INCREASING TO 10 TO POSSIBLY 15 KT THIS AFTERNOON AND
TONIGHT. SIGNIFICANT SEAS WILL RUN 2 TO 3 FT...EXCEPT UP TO 4 FT
ACROSS THE OUTER WATERS OFF CAPE FEAR THIS AFTERNOON AND/OR
TONIGHT. GENERALLY...A 1 1/2 TO 2 1/2 FOOT ESE GROUND SWELL
EXHIBITING 9 TO 12 SECOND PERIODS WILL DOMINATE SIG. SEAS. THE
ADDITION OF 3 TO 5 SECOND PERIOD WIND DRIVEN WAVES WILL PUSH SIG.
SEAS TO THE 4 FOOT LEVEL OFF CAPE FEAR LATER TODAY AND TONIGHT.
SEA FOG WILL ALSO REMAIN A THREAT TO MARINERS THIS FORECAST
PERIOD...OCCASIONALLY AND BRIEFLY MOVING ONSHORE. VSBY ROUGHLY 1
NM OR LESS WITHIN THE SEA FOG.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 245 AM MONDAY...SOUTHWEST FLOW REMAINS IN PLACE FOR A
MAJORITY OF THE PERIOD WITH SPEEDS GENERALLY 10 TO 15 KT. WEAK
SLOW MOVING FRONT DROPPING IN FROM THE NORTH-NORTHWEST LATE IN THE
PERIOD WILL BRING ABOUT A WIND SHIFT TO NORTHERLY BY THE END OF
THE PERIOD BUT LACK OF COLD ADVECTION OR SIGNIFICANT GRADIENT WILL
KEEP SPEEDS LIGHT...10 KT OR LESS. SEAS WILL RUN 2 TO 4 FT THROUGH
THE PERIOD...MAINLY AS SOUTHERLY WIND WAVE.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 245 AM MONDAY...NORTH TO NORTHEAST FLOW THU STARTS TO
INCREASE THU NIGHT...BUT QUESTION REMAINS BY HOW MUCH. WEAK LOW
PRESSURE EMERGING FROM NORTHEAST GOMEX WILL PINCH GRADIENT...BUT
HOW TIGHT GRADIENT BETWEEN THIS LOW AND THE HIGH BUILDING IN FROM
THE NORTHWEST BECOMES IS UNCERTAIN. ALL OF THE MEDIUM RANGE
GUIDANCE DEPICTS THIS SURFACE WAVE PASSING EAST OF THE WATERS
LATE THU NIGHT OR EARLY FRI...SO FEEL THAT AN INCREASE IN
NORTHEAST FLOW IS LIKELY FOR SECOND HALF OF THE PERIOD. AT THIS
POINT CANNOT SAY IF HEADLINES WILL BE NEEDED BUT IT CERTAINLY
APPEARS TO BE A POSSIBILITY. CURRENT SEAS FORECAST IS 2 TO 4 FT
THU BUILDING TO 3 TO 5 ON FRI. HOWEVER IT IS WORTH NOTING THAT WW3
GUIDANCE IS COMING IN CLOSE TO 10 FT FRI.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...RGZ
SHORT TERM...III
LONG TERM...III
AVIATION...DL
MARINE...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
641 AM EST MON JAN 14 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PRODUCE UNSEASONABLY WARM CONDITIONS
INTO MID-WEEK. A COLD FRONT WILL MOVE SLOWLY THROUGH THE AREA
LATE WEDNESDAY. WEAK GULF COAST LOW PRESSURE MAY BRING A CHANCE OF
LIGHT RAIN TO THE REGION THURSDAY NIGHT OR FRIDAY. HIGH PRESSURE
WILL BUILD IN BEHIND THE COLD FRONT FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM MONDAY...MODELS INDICATE THE MID TO UPPER LEVEL RIDGE
TO REMAIN ANCHORED JUST OFF THE SE U.S. COAST DURING THIS NEAR
TERM PERIOD. THIS WILL SLOW DOWN THE PROGRESSION OF THE BAROCLINIC
ZONE IE. THE SFC COLD FRONT...TOWARD THE SOUTHEAST. IN FACT...
MODELS ACTUALLY STALL THE COLD FRONT JUST NORTH AND WEST OF THE FA
AS IT BECOMES ORIENTED PARALLEL WITH THE FLOW ALOFT. THE DEEPEST
MOISTURE WILL REMAIN JUST OUTSIDE OF THE ILM CWA DURING THIS NEAR
TERM PERIOD...REMAINING WEST THROUGH NORTH OF THE FA. AMAZINGLY...
GFS/NAM/EUROPEAN/ETC. AGREE THAT THIS SCENARIO WILL PLAY OUT. NOW
WHAT THEY DO NOT AGREE IS THE THREAT OR PROBABILITY FOR PCPN. WITH
THE BEST LIFT REMAINING OUTSIDE OF THE ILM CWA DOMAIN...HAVE
INDICATED A LOW CHANCE OF POPS FOR THE NW PORTIONS OF THE FA FROM
THIS AFTERNOON THROUGH TONIGHT...ROUGHLY ALONG AND WEST OF THE
I-95 CORRIDOR. THE LATEST RUN OF THE HRRR MODEL ALSO INDICATES
THIS PCPN POSSIBILITY. HAVE STAYED AWAY FROM MENTIONING THUNDER
DUE TO THE LACK OF INSTABILITY ILLUSTRATED BY LATEST NAMBUFR
SOUNDINGS...IE. NO CAPE...LI`S STAY MAINLY POSITIVE. WILL LIKELY
HAVE A SOMEWHAT OF A SHARP CLOUD GRADIENT ACROSS THE FA WITH THE
IMMEDIATE COAST HAVING THE BEST POTENTIAL TO OBSERVE THE DAYS
INSOLATION. THEREFORE...HAVE RELIED ON THE WARMER MODEL MOS
GUIDANCE FOR BOTH TODAYS MAX AND TONIGHTS MIN TEMPS. THIS WILL
RESULT IN ADDITIONAL MAX TEMP RECORDS LIKELY BEING SET FOR 1 MORE
DAY. AND FINALLY...THE MID TO UPPER LEVEL CLOUD DECK ACROSS THE FA
HAS BEEN OPAQUE ENOUGH TO PREVENT WIDESPREAD RADIATIONAL TYPE
DENSE FOG. HOWEVER...SEA FOG IE. ADVECTION TYPE FOG...WILL
SPORADICALLY AFFECT THE IMMEDIATE COAST AS SFC WINDS SLIGHTLY BACK
TO THE SSW AND PUSH 60+ DEWPOINTS ACROSS SSTS IN THE 50S RESULTING
WITH SEA FOG BRIEFLY PUSHING ONSHORE AT TIMES.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 245 AM MONDAY...WEAK FRONT WILL BE STALLED IN OR JUST WEST
OF THE REGION FOR A MAJORITY OF THE PERIOD. PROXIMITY TO FRONT
WILL CREATE SIGNIFICANT TEMP GRADIENT ACROSS THE
REGION...PROVIDING PLENTY OF POTENTIAL FOR THE FORECAST TO GO
WRONG. SOME WEAK ISENTROPIC LIFT AND LOW LEVEL MOISTURE MAY
PRODUCE SOME PATCHY LIGHT RAIN AT TIMES. ALTHOUGH DRY MID AND
UPPER LEVELS WILL LIKELY KEEP MUCH OF THE AREA DRY FOR A MAJORITY
OF THE PERIOD. COMBINATION OF FRONT IN THE REGION AND LOW LEVEL
CLOUD COVER WILL TEMPER HIGHS ACROSS PORTIONS OF THE FORECAST AREA
BOTH DAYS. COASTAL SC ENDS UP WARMEST WITH A LITTLE LESS CLOUD
COVER AND SOUTHERLY FLOW INTO WED NIGHT. HIGHS WILL BE IN THE LOW
70S WITH LOWS IN THE UPPER 50S TO AROUND 60.
INLAND SC AND NC WILL HAVE BEST PRECIP CHANCES...THOUGH AT THIS
POINT LITTLE MORE THAN LOW CHANCE OR SLIGHT CHANCE APPEARS
WARRANTED. HIGH TEMP FORECAST WILL BE TRICKY IN THESE AREAS WITH
LOCATION OF FRONT...AND THE NORTHERLY FLOW BEHIND IT...LEADING TO A
SHARP GRADIENT SOMEWHERE IN THE FORECAST AREA. FOR NOW WILL GO WITH
HIGHS NEAR TO ABOVE CLIMO TUE AND ABOVE TO WELL ABOVE CLIMO WED.
HOWEVER A MORE EASTERLY POSITION OF THE FRONT WED...SOMETHING
GUIDANCE IS TRENDING AWAY FROM...WOULD RESULT IN COOLER TEMPS. LOWS
WILL CONTINUE TO RUN ABOVE CLIMO REGARDLESS OF FRONTAL POSITION
GIVEN PLENTY OF CLOUD COVER AND LIMITED COLD ADVECTION ON BACKSIDE
OF THE BOUNDARY.
FRONT IS PULLED OFF THE COAST WED NIGHT BY WEAK SURFACE LOW MOVING
INTO THE CANADIAN MARITIMES. LACK OF ANY MID LEVEL PUSH TRANSLATES
TO MINIMAL TEMP REDUCTION AS THE PERIOD ENDS. NORTH TO NORTHEAST
FLOW ACROSS THE AREA BY END OF PERIOD ONLY DROPS WED NIGHT LOWS A
FEW DEGREES.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 245 AM MONDAY...SOUTHERN STREAM SYSTEM EMERGING FROM THE
SOUTHWEST MID WEEK WILL BRING THE PERIODS BEST AND ONLY PRECIP
CHANCE THU NIGHT INTO FRI. DEEP SOUTHWEST FLOW AHEAD OF THE WAVE
AS IT CROSSES THE GULF COAST INCREASES MOISTURE OVER THE
SOUTHEAST THU. DIVERGENT PATTERN ALOFT THU NIGHT INTO FRI IS
ENHANCED BY 200MB JET STREAK APPROACHING 120 KT. RIGHT NOW THE
BIGGEST NEGATIVE FACTOR APPEARS TO BE THE TRACK OF THE MID LEVEL
FEATURE AND THE ASSOCIATED SURFACE WAVE. WEAK SURFACE LOW DEVELOPS
ALONG FRONT STALLED ACROSS NORTHERN GOMEX EARLY THU. THIS LOW
TRACKS NORTHEAST ALONG THE FRONT...PASSING OFF THE SOUTHEAST COAST.
THIS KEEPS NORTHEAST LOW LEVEL FLOW IN PLACE FOR THE DURATION OF
THE EVENT. BELOW 700MB OR SO FORECAST SOUNDINGS DEPICT A SATURATED
BUT VERY STABLE AIR MASS. SO WHILE MID AND UPPER LEVEL FORCING
WILL BE PRESENT IT APPEARS THE LOW LEVEL STABILITY WILL ULTIMATELY
WIN OUT. THUS HAVE GONE FOR LOWER POP AND MINIMAL QPF EARLY IN THE
PERIOD.
AS SURFACE AND MID LEVEL FEATURES MOVE OFF TO THE NORTHEAST HIGH
PRESSURE BUILDS IN UNDER DEVELOPING PROGRESSIVE MID LEVEL PATTERN.
THIS ALLOWS MUCH DRIER AND COOLER AIR TO SPREAD IN FROM THE WEST.
PINCHED GRADIENT ALONG THE COAST WILL KEEP NORTHEAST FLOW BRISK INTO
SAT MORNING...ESPECIALLY ALONG THE COAST. LATE IN THE PERIOD MEDIUM
RANGE GUIDANCE IS TRYING TO SHOW A WEAK COASTAL LOW DEVELOPING ON
REMAINS OF STALLED SURFACE BOUNDARY. GIVEN THE TIME RANGE AND
POTENTIAL FOR SIGNIFICANT CHANGES REGARDING THIS FEATURE WILL NOT
INTRODUCE A POP LATE IN THE PERIOD. TEMPS NEAR CLIMO THROUGH THE
PERIOD.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 12Z...LBT IS LIFR AND WILL LIKELY NOT REACH VFR UNTIL
14Z...PERHAPS EVEN AN HOUR LATER. THE OTHER TERMINALS APPEAR TO HAVE
ENOUGH SOUTHWEST FLOW TO MIX OUT A BIT EARLIER. STAGNANT SYNOPTIC
PATTERN WILL KEEP THE FRONT WEST OF THE REGION...WITH MAINLY THICK
HIGH CLOUDS IN AND OUT OF OUR WESTERN TERMINALS. ALONG THE
COAST...GOOD LOW LEVEL MOISTURE WILL GIVE US A CHANCE OF AN MVFR
CEILING IN AND OUT THROUGH EARLY AFTERNOON. SOUTHWEST FLOW WILL
CONTINUE THROUGH THE OVERNIGHT HOURS. IT APPEARS THE WINDS WILL BE
TOO STRONG TO SUPPORT FOG...BUT WILL REEVALUATE ON THE NEXT SET OF
TAFS.
EXTENDED OUTLOOK...POSSIBLE RESTRICTIONS IN ASSOCIATION WITH COLD
FRONT TUESDAY AND WEDNESDAY...MAINLY AT THE INLAND TERMINALS.
CHANCE FOR SHOWERS THURSDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM MONDAY...SFC PRESSURE PATTERN INDICATES THE WESTERN
ATLANTIC HIGH...CENTERED OFFSHORE FROM THE SE U.S. COAST...WILL
PRODUCE SSW THROUGH WSW WIND DIRECTIONS. THE SFC PG WILL SLIGHTLY
TIGHTEN AS THE SFC COLD FRONT APPROACHES FROM THE NW TODAY...
BEFORE STALLING BETWEEN DUCK NC SOUTHWEST TO PENSACOLA BEACH
FLORIDA TONIGHT. LOOK FOR WIND SPEEDS AT 5 TO 10 KT THIS
MORNING...INCREASING TO 10 TO POSSIBLY 15 KT THIS AFTERNOON AND
TONIGHT. SIGNIFICANT SEAS WILL RUN 2 TO 3 FT...EXCEPT UP TO 4 FT
ACROSS THE OUTER WATERS OFF CAPE FEAR THIS AFTERNOON AND/OR
TONIGHT. GENERALLY...A 1 1/2 TO 2 1/2 FOOT ESE GROUND SWELL
EXHIBITING 9 TO 12 SECOND PERIODS WILL DOMINATE SIG. SEAS. THE
ADDITION OF 3 TO 5 SECOND PERIOD WIND DRIVEN WAVES WILL PUSH SIG.
SEAS TO THE 4 FOOT LEVEL OFF CAPE FEAR LATER TODAY AND TONIGHT.
SEA FOG WILL ALSO REMAIN A THREAT TO MARINERS THIS FORECAST
PERIOD...OCCASIONALLY AND BRIEFLY MOVING ONSHORE. VSBY ROUGHLY 1
NM OR LESS WITHIN THE SEA FOG.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 245 AM MONDAY...SOUTHWEST FLOW REMAINS IN PLACE FOR A
MAJORITY OF THE PERIOD WITH SPEEDS GENERALLY 10 TO 15 KT. WEAK
SLOW MOVING FRONT DROPPING IN FROM THE NORTH-NORTHWEST LATE IN THE
PERIOD WILL BRING ABOUT A WIND SHIFT TO NORTHERLY BY THE END OF
THE PERIOD BUT LACK OF COLD ADVECTION OR SIGNIFICANT GRADIENT WILL
KEEP SPEEDS LIGHT...10 KT OR LESS. SEAS WILL RUN 2 TO 4 FT THROUGH
THE PERIOD...MAINLY AS SOUTHERLY WIND WAVE.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 245 AM MONDAY...NORTH TO NORTHEAST FLOW THU STARTS TO
INCREASE THU NIGHT...BUT QUESTION REMAINS BY HOW MUCH. WEAK LOW
PRESSURE EMERGING FROM NORTHEAST GOMEX WILL PINCH GRADIENT...BUT
HOW TIGHT GRADIENT BETWEEN THIS LOW AND THE HIGH BUILDING IN FROM
THE NORTHWEST BECOMES IS UNCERTAIN. ALL OF THE MEDIUM RANGE
GUIDANCE DEPICTS THIS SURFACE WAVE PASSING EAST OF THE WATERS
LATE THU NIGHT OR EARLY FRI...SO FEEL THAT AN INCREASE IN
NORTHEAST FLOW IS LIKELY FOR SECOND HALF OF THE PERIOD. AT THIS
POINT CANNOT SAY IF HEADLINES WILL BE NEEDED BUT IT CERTAINLY
APPEARS TO BE A POSSIBILITY. CURRENT SEAS FORECAST IS 2 TO 4 FT
THU BUILDING TO 3 TO 5 ON FRI. HOWEVER IT IS WORTH NOTING THAT WW3
GUIDANCE IS COMING IN CLOSE TO 10 FT FRI.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...III
NEAR TERM...DCH
SHORT TERM...III
LONG TERM...III
AVIATION...DCH/SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
636 AM EST MON JAN 14 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH THE FIRST PART OF
THE WORK WEEK. THIS WILL LEAD TO MAINLY DRY CONDITIONS AND MORE
SEASONABLE TEMPERATURES THROUGH WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH THIS AFTERNOON.
AS IT DOES...NORTH TO NORTHWEST LOW LEVEL FLOW WILL DECREASE BUT
WEAK CAA WILL CONTINUE THROUGH MUCH OF THE DAY. A FAIR AMOUNT OF
LOW CLOUDS ARE STILL IN PLACE ACROSS THE REGION BUT SATELLITE
IMAGES ARE INDICATING SOME BREAKS ACROSS PARTS OF OUR SOUTHWEST.
MAIN QUESTION FOR TODAY WILL BE HOW FAST THESE CLOUDS DISSIPATE.
THE RAP IS HANGING ON TO A FAIR AMOUNT OF LOW LEVEL MOISTURE
THROUGH THIS AFTERNOON. THIS IS PROBABLY OVERDONE AND PREFER
SOMETHING CLOSER TO WHAT THE NAM IS INDICATING ALTHOUGH THE WEAK
CAA MAY HELP KEEP THE CLOUDS AROUND A BIT LONGER. WILL THEREFORE
ALLOW FOR PARTIAL CLEARING HEADING THROUGH LATE MORNING INTO EARLY
AFTERNOON. 500 MB MOISTURE WILL INCREASE FROM THE SOUTHWEST LATER
THIS AFTERNOON AND THIS COULD ALLOW FOR AN INCREASE IN SOME
HIGHER LEVEL CLOUDS LATER TODAY. WITH WEAK CAA...EXPECT HIGHS
RANGING FROM THE UPPER 20S TO LOWER 30S IN THE NORTHWEST TO THE
MID AND UPPER 30S ACROSS THE SOUTHEAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
SURFACE HIGH PRESSURE WILL REMAIN ACROSS THE AREA TUESDAY INTO
WEDNESDAY...PROVIDING MAINLY DRY CONDITIONS. THE ONE EXCEPTION
COULD BE ACROSS OUR FAR SOUTHEAST AS A COUPLE OF SHORT WAVES RIDE
UP ALONG THE APPALACHIANS. THE MODELS HAVE TRENDED A BIT FARTHER
NORTH WITH THEIR NORTHERN PERIPHERY WITH THE INITIAL WAVE TONIGHT
AND THEN THE SECOND ONE FOR TUESDAY NIGHT. BOTH THE 00Z ECMWF AND
GFS ARE TRYING TO BRUSH A FEW OF OUR SOUTHEASTERN COUNTIES WITH
PCPN WHILE THE 00Z AND 06Z NAM ARE KEEPING EVERYTHING TO THE
SOUTH. GIVEN THE TRENDS...WILL GO AHEAD AND INTRODUCE SOME POPS
ACROSS THE FAR SOUTHEAST FOR TONIGHT AND TUESDAY NIGHT...BUT KEEP
THEM LOW AT THIS POINT. FORECAST SOUNDINGS ARE INDICATING THE
POSSIBILITY OF A RAIN/SNOW MIX WITH ANY PCPN BUT GIVEN THAT IT
WOULD BE AT NIGHT...IT MAY BE MORE LIKELY TO BE SNOW THAN RAIN.
CLOUDS WILL BE DEPENDENT ON JUST HOW FAR NORTH THESE WAVES MAKE IT
AND THIS WILL ALSO HAVE AN AFFECT ON LOW TEMPERATURES BOTH TONIGHT
AND TUESDAY NIGHT. WILL GO AHEAD AND ALLOW FOR A DECENT GRADIENT
BOTH NIGHTS FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE BUILDS BACK INTO THE OH AND TN VALLEYS THU INTO
FRI.
ENERGY KEEPS RUNNING THROUGH THE SUBTLE ERN U.S. LONGWAVE TROF OVER
THE WEEKEND. GFS AND ECMWF DIFFER ON THE STRENGTH OF A SYSTEM ON
SATURDAY....BUT BOTH PUSH COOLER AIR IN ON SUNDAY WITH A TRAILING
COLD FRONT. ONCE AGAIN THE MOISTURE IS LOOKING LIMITED FOR
SUNDAY...SO KEPT THE FCST DRY.
COOLER AIR BEHIND WEDNESDAYS SYSTEM WILL FILTER IN FOR
THU...DROPPING HIGHS INTO 30S. THE SEE-SAW TEMPERATURES WILL
CONTINUE...AS A WARMER AIR WORKS BACK IN FOR FRIDAY AND SATURDAY.
HIGHS FRIDAY WILL BE IN THE UPPER 30S TO LOWER 40S...WITH 40S FOR
HIGHS ON SATURDAY. TEMPERATURES WILL TAKE ANOTHER DOWN TURN ON
SUNDAY AS HIGHS WILL RANGE FROM THE MID 30S IN THE N TO MID 40S IN
NRN KY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
CLOUD DECK AROUND 1000 TO 1500 FEET AGL ASSOCIATED WITH RESIDUAL
LOW LEVEL MOISTURE WILL KEEP CIGS MAINLY MVFR WITH A COUPLE IFR
SPOTS THROUGHOUT THE MORNING. AS THE DAY PROGRESSES THIS DECK
SHOULD THIN AS DRIER AIR BEGINS TO MIX INTO THE LOW LEVELS.
CURRENT FORECAST CALLS FOR CLOUDS TO SCATTER TO VFR BY THE LATE
MORNING STARTING ACROSS THE SOUTHERN TERMINALS KCVG/KLUK...AND
INTO THE EARLY AFTERNOON TOWARD THE NORTHERN TERMINALS.
AS LOW LEVEL WINDS BEGIN TO VEER OUT OF THE NORTHEAST LATE THIS
AFTERNOON...IT IS POSSIBLE THAT SOME OF THE MVFR CIGS MAY TRY TO
PUSH SOUTH ACROSS THE NORTHERN TERMINALS. KEPT THE FORECAST A BIT
MORE OPTIMISTIC WITH VFR CONDITIONS EXPECTED FROM THIS AFTERNOON
ONWARD THROUGH THE REST OF THE TAF PERIOD. THIS EVENING...A
DISTURBANCE PASSING BY TO OUR SOUTH WILL BRING VFR CLOUD COVER
ACROSS THE AREA. PRECIPITATION ASSOCIATED WITH THIS DISTURBANCE IS
EXPECTED TO REMAIN SOUTH OF OUR TERMINALS.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...SITES
AVIATION...LATTO
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
450 AM CST MON JAN 14 2013
.DISCUSSION...
FAIRLY QUIET WEEK AHEAD...WITH MAIN ENERGY FROM A COUPLE OF WAVES
EXPECTED TO REMAIN NORTH OF THE AREA...LEAVING TEMPERATURES AS
PRIMARY CONCERN THROUGH NEXT WEEKEND.
FOR TODAY...WEAK WAVE SLIDING NORTHEAST ACROSS OUR AREA AHEAD OF
MID-UPPER TROUGH DROPPING SOUTHEAST INTO THE UPPER MIDWEST. WITH
COLD AIR MASS STILL IN PLACE AND WEAK LIFT FROM THIS WAVE...STILL
SEEING FLURRIES BEING SQUEEZED OUT OF ANY LOWER/DEEPER MOISTURE
LAYERS. RAP SEEMS TO BE HANDLING THE MOISTURE FAIRLY WELL...AND
KEEPS DEEPER MOISTURE ACROSS CENTRAL/NORTHERN CWA THIS MORNING...
SHIFTING EAST OF THE AREA THROUGH THE AFTERNOON. DEEPER MOISTURE
AGAIN LIES IN FAVORABLE TEMPERATURE ZONE FOR ICE PRODUCTION /A FEW
DEGREES EITHER SIDE OF -15C/...THUS HAVE ADDED SCATTERED FLURRIES
ALONG/NORTH OF I-90 THROUGH MIDDAY.
TEMPERATURES SHOULD REBOUND A BIT FROM WEEKEND CHILL AS WARMER LOW
LEVEL AIR BEGINS TO WORK INTO THE AREA THIS AFTERNOON. STILL ONE
MORE DAY BELOW NORMAL THOUGH... WITH HIGHS IN THE TEENS TO LOWER
20S. ONE THING OF NOTE ON TEMPS THROUGHOUT MUCH OF THE FORECAST...
NAM/GFS APPEAR TO HAVE POORLY INITIALIZED SNOW COVER IN THE MODEL...
WHICH SEEMS TO BE HAVING A LARGE EFFECT ON THEIR RESPECTIVE SURFACE
TEMPERATURE FORECASTS... SEEN BOTH IN THE RAW MODELS/MOS OUTPUT...
THOUGH SOMEWHAT LESSER EXTENT IN THE LATTER. THUS HAVE CHOSEN TO
FAVOR WARMER GEM/ECMWF TEMPERATURES THROUGH MOST OF THE WEEK...
ESPECIALLY THROUGH FRIDAY WHEN WARM AIR ALOFT REMAINS IN PLACE.
NEXT WAVE MOVES ACROSS THE REGION TUESDAY/TUESDAY NIGHT. STRONG WARM
ADVECTION WILL LEAD TO POTENTIAL FOR A LITTLE LIGHT SNOW OR FLURRIES
AHEAD OF THE WARM AIR...WHICH WILL SPREAD ACROSS THE FORECAST AREA
IN EARNEST TUESDAY NIGHT. LITTLE ACCUMULATION EXPECTED...WITH MAYBE
A QUARTER INCH OR SO ALONG THE HIGHWAY 14 CORRIDOR. STOUT SOUTHWEST
FLOW AHEAD OF THE WARM FRONT WILL RESULT IN GUSTY WINDS ATOP AND
DOWNSTREAM OF THE BUFFALO RIDGE MUCH OF THE NIGHT. EXPECT EARLY
EVENING LOWS FROM AROUND 20 IN THE EAST TO THE MID-UPPER 20S WEST OF
THE JAMES VALLEY...WITH MOST AREAS WARMING TO NEAR FREEZING OR JUST
SHY BY DAYBREAK WEDNESDAY AS WINDS TURN TO THE WEST BEHIND THE WARM
FRONT. STILL LOOKS LIKE A MILD DAY WITH TEMPS ONLY WARMING A FEW
MORE DEGREES THROUGH THE DAY TO HIGHS OF 35 TO 45.
BACKDOOR COOL FRONT DROPS THROUGH NORTHEAST PORTIONS OF THE FORECAST
AREA WEDNESDAY NIGHT/THURSDAY. TEMPERATURES STILL EXPECTED TO BE
ABOVE NORMAL THURSDAY THOUGH...WITH HIGHS UPPER 20S NORTHEAST TO THE
MID 30S THROUGH THE MISSOURI VALLEY. GEM/ECMWF BOTH SHOWING ANOTHER
WARM PUSH FRIDAY AHEAD OF STRONGER PUSH OF COLD AIR EXPECTED NEXT
WEEKEND. HAVE NUDGED TEMPERATURES A FEW DEGREES ABOVE GENERAL MODEL
CONSENSUS...THOUGH COULD BE EVEN WARMER IF 14/00Z ECMWF PANS OUT.
A COUPLE OF QUICK MOVING WAVES DIVE SOUTHEAST ACROSS NORTH DAKOTA
AND NORTHERN MINNESOTA DURING THE LONGER RANGE. THE FIRST WEAKER
WAVE MOVES THROUGH THURSDAY NIGHT...LEAVING A TIGHTENING THERMAL
GRADIENT WHICH NEXT STRONGER WAVE CAN WORK WITH SATURDAY. THIS WAVE
WILL PUSH THE ARCTIC FRONT SOUTH THROUGH THE REGION...BRINGING A
RETURN TO BELOW NORMAL TEMPERATURES BY THE LATTER HALF OF NEXT
WEEKEND. AS WAS MENTIONED ABOVE...ENERGY APPEARS TO REMAIN WELL
NORTH OF OUR AREA AT THIS TIME...SO WILL KEEP THE LONGER RANGE DRY
FOR NOW. HOWEVER WILL HAVE TO WATCH FOR POTENTIAL OF SOME LIGHT SNOW
SUNDAY AS YET ANOTHER WAVE DROPS INTO THE ARCTIC AIR MASS WHICH IS
EXPECTED TO PUSH BACK INTO THE REGION BY THEN.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
AN AREA OF CEILINGS 1-3K FEET SHOULD BE EXITING SOUTHWEST MN BY 15Z.
OTHERWISE VFR IS EXPECTED OVER THE AREA THROUGH 15/12Z. AREAS OF
CEILINGS 3-5K FEET WILL PASS OVER THE AREA NORTH OF INTERSTATE 90
THROUGH 15/06Z WITH CEILINGS ELSEWHERE UNRESTRICTED OR ABOVE 5K
FEET. IT APPEARS AIR WILL BE TOO DRY FOR PATCHY FOG IN LIGHT WIND
REGIME NEAR END OF PERIOD AT 15/12Z. SURFACE WINDS SHOULD BE 10
KNOTS OR LESS THROUGH 15/12Z.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
415 AM CST MON JAN 14 2013
.DISCUSSION...
FAIRLY QUIET WEEK AHEAD...WITH MAIN ENERGY FROM A COUPLE OF WAVES
EXPECTED TO REMAIN NORTH OF THE AREA...LEAVING TEMPERATURES AS
PRIMARY CONCERN THROUGH NEXT WEEKEND.
FOR TODAY...WEAK WAVE SLIDING NORTHEAST ACROSS OUR AREA AHEAD OF
MID-UPPER TROUGH DROPPING SOUTHEAST INTO THE UPPER MIDWEST. WITH
COLD AIR MASS STILL IN PLACE AND WEAK LIFT FROM THIS WAVE...STILL
SEEING FLURRIES BEING SQUEEZED OUT OF ANY LOWER/DEEPER MOISTURE
LAYERS. RAP SEEMS TO BE HANDLING THE MOISTURE FAIRLY WELL...AND
KEEPS DEEPER MOISTURE ACROSS CENTRAL/NORTHERN CWA THIS MORNING...
SHIFTING EAST OF THE AREA THROUGH THE AFTERNOON. DEEPER MOISTURE
AGAIN LIES IN FAVORABLE TEMPERATURE ZONE FOR ICE PRODUCTION /A FEW
DEGREES EITHER SIDE OF -15C/...THUS HAVE ADDED SCATTERED FLURRIES
ALONG/NORTH OF I-90 THROUGH MIDDAY.
TEMPERATURES SHOULD REBOUND A BIT FROM WEEKEND CHILL AS WARMER LOW
LEVEL AIR BEGINS TO WORK INTO THE AREA THIS AFTERNOON. STILL ONE
MORE DAY BELOW NORMAL THOUGH... WITH HIGHS IN THE TEENS TO LOWER
20S. ONE THING OF NOTE ON TEMPS THROUGHOUT MUCH OF THE FORECAST...
NAM/GFS APPEAR TO HAVE POORLY INITIALIZED SNOW COVER IN THE MODEL...
WHICH SEEMS TO BE HAVING A LARGE EFFECT ON THEIR RESPECTIVE SURFACE
TEMPERATURE FORECASTS... SEEN BOTH IN THE RAW MODELS/MOS OUTPUT...
THOUGH SOMEWHAT LESSER EXTENT IN THE LATTER. THUS HAVE CHOSEN TO
FAVOR WARMER GEM/ECMWF TEMPERATURES THROUGH MOST OF THE WEEK...
ESPECIALLY THROUGH FRIDAY WHEN WARM AIR ALOFT REMAINS IN PLACE.
NEXT WAVE MOVES ACROSS THE REGION TUESDAY/TUESDAY NIGHT. STRONG WARM
ADVECTION WILL LEAD TO POTENTIAL FOR A LITTLE LIGHT SNOW OR FLURRIES
AHEAD OF THE WARM AIR...WHICH WILL SPREAD ACROSS THE FORECAST AREA
IN EARNEST TUESDAY NIGHT. LITTLE ACCUMULATION EXPECTED...WITH MAYBE
A QUARTER INCH OR SO ALONG THE HIGHWAY 14 CORRIDOR. STOUT SOUTHWEST
FLOW AHEAD OF THE WARM FRONT WILL RESULT IN GUSTY WINDS ATOP AND
DOWNSTREAM OF THE BUFFALO RIDGE MUCH OF THE NIGHT. EXPECT EARLY
EVENING LOWS FROM AROUND 20 IN THE EAST TO THE MID-UPPER 20S WEST OF
THE JAMES VALLEY...WITH MOST AREAS WARMING TO NEAR FREEZING OR JUST
SHY BY DAYBREAK WEDNESDAY AS WINDS TURN TO THE WEST BEHIND THE WARM
FRONT. STILL LOOKS LIKE A MILD DAY WITH TEMPS ONLY WARMING A FEW
MORE DEGREES THROUGH THE DAY TO HIGHS OF 35 TO 45.
BACKDOOR COOL FRONT DROPS THROUGH NORTHEAST PORTIONS OF THE FORECAST
AREA WEDNESDAY NIGHT/THURSDAY. TEMPERATURES STILL EXPECTED TO BE
ABOVE NORMAL THURSDAY THOUGH...WITH HIGHS UPPER 20S NORTHEAST TO THE
MID 30S THROUGH THE MISSOURI VALLEY. GEM/ECMWF BOTH SHOWING ANOTHER
WARM PUSH FRIDAY AHEAD OF STRONGER PUSH OF COLD AIR EXPECTED NEXT
WEEKEND. HAVE NUDGED TEMPERATURES A FEW DEGREES ABOVE GENERAL MODEL
CONSENSUS...THOUGH COULD BE EVEN WARMER IF 14/00Z ECMWF PANS OUT.
A COUPLE OF QUICK MOVING WAVES DIVE SOUTHEAST ACROSS NORTH DAKOTA
AND NORTHERN MINNESOTA DURING THE LONGER RANGE. THE FIRST WEAKER
WAVE MOVES THROUGH THURSDAY NIGHT...LEAVING A TIGHTENING THERMAL
GRADIENT WHICH NEXT STRONGER WAVE CAN WORK WITH SATURDAY. THIS WAVE
WILL PUSH THE ARCTIC FRONT SOUTH THROUGH THE REGION...BRINGING A
RETURN TO BELOW NORMAL TEMPERATURES BY THE LATTER HALF OF NEXT
WEEKEND. AS WAS MENTIONED ABOVE...ENERGY APPEARS TO REMAIN WELL
NORTH OF OUR AREA AT THIS TIME...SO WILL KEEP THE LONGER RANGE DRY
FOR NOW. HOWEVER WILL HAVE TO WATCH FOR POTENTIAL OF SOME LIGHT SNOW
SUNDAY AS YET ANOTHER WAVE DROPS INTO THE ARCTIC AIR MASS WHICH IS
EXPECTED TO PUSH BACK INTO THE REGION BY THEN.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
AN AREA OF STRATUS AROUND 3000 FEET WILL AFFECT THE NORTHERN CWA
THROUGH THE OVERNIGHT HOURS AFFECTING BOTH THE KHON AND KFSD
TERMINALS. THERE MAYBE A FEW FLURRIES ASSOCIATED WITH THIS BAND OF
STRATUS...BUT IS NOT EXPECTED TO REDUCE VISIBILITY. THEREAFTER..VFR
CONDITIONS ARE EXPECTED TO PREVAIL WITH LIGHT WESTERLY WINDS
BECOMING SOUTHWEST.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
949 AM CST MON JAN 14 2013
.UPDATE...MOSTLY SUNNY SKIES WILL CONTINUE THROUGH THE MORNING.
COULD SEE SOME HIGH CLOUDS MOVE IN FROM THE SOUTH THIS
AFTERNOON...AND AN AREA OF LOW CLOUDS MAY ALSO MOVE INTO THE
NORTHWEST FORECAST AREA BY LATE AFTERNOON. OTHERWISE...A
QUIET...BUT CHILLY DAY STILL EXPECTED WITH HIGHS A FEW DEGREES
BELOW NORMAL.
&&
.AVIATION/18Z TAFS/...WATCHING AN AREA OF MVFR CIGS UPSTREAM.
LATEST RAP AND NAM RH FIELDS INDICATE THIS MAY HOLD TOGETHER AND
MOVE INTO THE NORTHWEST HALF OF THE FORECAST AREA MID TO LATE THIS
AFTERNOON. BEST CHANCE FOR THESE LOWER CIGS APPEARS TO BE ROUGHLY
ALONG AND NORTHWEST OF A MINERAL POINT TO SHEBOYGAN LINE...AS THE
HIGH RH IN THE MODELS NEVER QUITE MAKES IT TO THE SOUTHEAST. WILL
KEEP AN EYE ON SATELLITE TRENDS AND CONSIDER ADDING SOME LOWER
CIGS TO THE TAFS.
ANY LOWER CIGS SHOULD SCATTER OUT OR MOVE OUT BY MORNING...WITH VFR
CONDITIONS THEN EXPECTED THROUGH THE DAY TUESDAY.
&&
.PREV DISCUSSION... /ISSUED 321 AM CST MON JAN 14 2013/
TODAY AND TONIGHT...FORECAST CONFIDENCE IS HIGH.
HIGH PRESSURE SLIDING INTO THE AREA WILL BRING QUIET WEATHER TO
REGION. A COLD START TO THE DAY...COUPLED WITH A DECENT THERMAL
TROUGH LINGERING OVER THE WESTERN GREAT LAKES MEANS TEMPS WON/T
RECOVER VERY FAST TODAY. THIS WILL PROBABLY BE THE COLDEST DAY OF
THE WEEK...THOUGH THURSDAY WILL CHALLENGE IT.
SOME LOWER CLOUDS ASSOCIATED WITH WEAK COLD AIR ADVECTION OVER
THE EASTERN DAKOTAS AND MINNESOTA MAY SNEAK INTO THE NORTHWEST CWA
TOWARD EVENING. BUT THIS SHOULDN/T MAKE MUCH HEADWAY BEYOND THAT
BEFORE LIFTING TO THE NORTH OR DIMINISHING AS THE CAA WEAKENS.
ALSO...SOME CIRRUS MAY STREAM IN FROM THE SOUTHWEST TODAY AND
TONIGHT AS A VERY STRONG UPPER LEVEL JET WILL BE CENTERED FROM
OKLAHOMA NORTHEAST INTO LOWER MICHIGAN.
TEMPS TONIGHT WILL BE A LITTLE TRICKY AND VERY DEPENDENT ON THE
THICKNESS OF THE POSSIBLE CLOUDS. THOSE CLOUDS AREN/T A
CERTAINTY...SO PLAYED IT CAUTIOUSLY. ANOTHER COLD NIGHT ON TAP
BEFORE TEMPS RISE INTO THE MIDDLE OF THE WEEK.
TUESDAY THROUGH WEDNESDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM.
SHORT TERM MODELS SHOWING 500MB FLOW WEST SOUTHWEST
TUESDAY...BEFORE A SHORTWAVE TROUGH SLIDES EAST ACROSS THE REGION
LATER TUESDAY AND TUESDAY EVENING. 500MB WINDS GRADUALLY VEER WEST
NORTHWEST BEHIND THE SHORTWAVE TROUGH LATER TUESDAY NIGHT THROUGH
WEDNESDAY NIGHT. GFS/CANADIAN BRING A VORTICITY MAXIMUM INTO
NORTHERN PORTIONS OF THE AREA WEDNESDAY NIGHT...WITH THE NAM WELL
NORTH OF THE AREA WITH THIS FEATURE. THE ECMWF BRINGS THIS FEATURE
IN WEDNESDAY.
AT THE SURFACE...HIGH PRESSURE TO THE SOUTH OF THE AREA TUESDAY
WILL SLIDE TO THE SOUTH SOUTHWEST TUESDAY NIGHT. MEANWHILE...WARM
AIR ADVECTION MOVES INTO THE AREA TUESDAY NIGHT INTO
WEDNESDAY...WITH STRONG LOW PRESSURE PASSING WELL NORTHEAST OF THE
AREA.
MODEST Q VECTOR CONVERGENCE SEEN ACROSS NORTHWESTERN AND NORTHERN
PORTIONS OF THE AREA TUESDAY NIGHT INTO WEDNESDAY...THOUGH MODELS
HAVE DRY TUESDAY NIGHT AND VERY LIGHT/SPOTTY QPF WEDNESDAY
MORNING. AREA FORECAST SOUNDINGS TRY TO MOISTEN UP WEDNESDAY
MORNING. KEPT LOW END POPS FOR WEDNESDAY MORNING IN THE FAR
NORTHERN COUNTIES.
PRESSURE GRADIENT GETS TIGHT TUESDAY NIGHT INTO WEDNESDAY...WHICH
WILL BRING BRISK WEST WINDS. TEMPERATURES WILL MODERATE A BIT
DURING THIS PERIOD.
COLD FRONT SLIDES SOUTHEAST THROUGH THE AREA WEDNESDAY AFTERNOON
AND EVENING...WITH THE ECMWF/CANADIAN QUICKER THAN THE GFS/NAM.
CANADIAN IS MOST AGGRESSIVE MODEL WITH QPF ACROSS THE AREA DURING
THIS TIME...WITH LIGHT QPF IN THE EVENING ON THE GFS...AND THE
NAM/ECMWF DRY.
WEAK TO MODEST UPWARD MOTION SEEN ON 850MB TO 700MB FRONTOGENESIS
RESPONSE FIELDS DURING THIS TIME. KEPT SMALL CHANCES FOR LIGHT
SNOW SHOWERS GOING FOR FAR NORTHERN AND NORTHEASTERN PORTIONS OF
THE AREA FOR THIS TIME. GFS/ECMWF/CANADIAN SHOW STRONG COLD AIR
ADVECTION AFTER THE COLD FRONTAL PASSAGE WEDNESDAY NIGHT...WITH
THE NAM MUCH WARMER. TRENDED TOWARD THE COOLER SOLUTIONS FOR
TEMPERATURES WEDNESDAY NIGHT.
THURSDAY THROUGH SUNDAY...FORECAST CONFIDENCE IS MEDIUM.
ECMWF/GFS SHOW SOME DIFFERENCES DURING THIS PERIOD ACROSS THE
AREA. THEY BOTH DO SHOW WEAK HIGH PRESSURE TO THE WEST KEEPING
QUIET WEATHER ACROSS THE AREA FOR THURSDAY.
ECMWF THEN BRINGS A WARM FRONT ACROSS THE AREA LATE THURSDAY
NIGHT WITH AN AREA OF QPF CLIPPING THE FAR NORTH...EXITING BY
FRIDAY AFTERNOON. IT IS THEN DRY THROUGH SATURDAY ACROSS THE
REGION.
GFS KEEPS THURSDAY NIGHT DRY...WITH THE WARM FRONT THEN SETTING
UP WEST TO EAST ACROSS THE FAR NORTHERN COUNTIES FRIDAY. THIS
KEEPS MOST OF THE QPF JUST NORTH OF THE FORECAST AREA FRIDAY AND
FRIDAY NIGHT. USED CONSENSUS POPS AND TEMPERATURES FOR THURSDAY
THROUGH FRIDAY NIGHT...GIVEN THE DIFFERENCES IN THE MODELS.
THE GFS THEN DEVELOPS LOW PRESSURE OVER NORTHERN LOWER MICHIGAN BY
00Z SUNDAY...WITH A STRONG COLD FRONT PUSHING SOUTHEAST THROUGH
THE AREA. STRONG COLD AIR ADVECTION THEN BRINGS A VERY COLD
AIRMASS INTO THE AREA FOR SATURDAY NIGHT AND SUNDAY.
THE ECMWF DELAYS THIS SYSTEM UNTIL SATURDAY NIGHT. GFS CLIPS THE
NORTHEASTERN HALF OF THE AREA WITH QPF SATURDAY. THE ECMWF DOES
HAVE LIGHT QPF JUST MISSING THE AREA SATURDAY NIGHT WITH A PASSING
VORTICITY MAXIMUM TO THE NORTH. AGAIN...USED CONSENSUS POPS AND
TEMPERATURES FOR THIS PERIOD WITH THE UNCERTAINTY IN THE MODELS.
AVIATION/12Z TAFS/...HIGH PRESSURE WILL BRING VFR CONDITIONS TO
THE AREA THROUGH THE TAF PERIOD. JUST SOME HIGH CLOUDS MOSTLY.
MARINE...A STRONG LOW PRESSURE SYSTEM PASSING JUST NORTH OF THE
U.S./CANADIAN BORDER LATE TUESDAY NIGHT THROUGH WEDNESDAY WILL
LIKELY RESULT IN SMALL CRAFT ADVISORY CONDITIONS DURING THIS
PERIOD. EXPECT BRISK SOUTHWEST WINDS OF 15 TO 25 KNOTS VEERING
WEST WITH TIME. A FEW GALE GUSTS TO 35 KNOTS WILL BE POSSIBLE.
WAVES OF 3 TO 6 FEET ARE LIKELY...WITH THE HIGHEST WAVES TOWARD
OPEN WATER.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...DDV
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
TUESDAY THROUGH SUNDAY...WOOD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
516 AM CST MON JAN 14 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY
322 AM CST MON JAN 14 2013
AT 3 AM...A SURFACE TROUGH WAS LOCATED ACROSS SOUTHWEST MINNESOTA.
THIS TROUGH IS CURRENTLY PRODUCING A MVFR DECK OF CLOUDS ACROSS
EASTERN SOUTH DAKOTA AND SOUTHWEST MINNESOTA. THERE ARE EVEN
FLURRIES BEING REPORTED AT SIOUX FALLS SOUTH DAKOTA. FURTHER TO
THE SOUTHWEST...THE WATER VAPOR IMAGERY SHOWS A SHORT WAVE TROUGH
MOVING OUT OF COLORADO. THIS SYSTEM HAS BEEN PRODUCING SOME LIGHT
SNOW FROM COLORADO INTO CENTRAL SOUTH DAKOTA. THE 14.00Z MODELS
ARE IN GOOD AGREEMENT THAT THE SURFACE TROUGH WILL MOVE SLOWLY
EAST AND GRADUALLY WEAKEN TODAY. MEANWHILE THE SHORT WAVE WILL
MOVE ACROSS THE AREA THIS AFTERNOON. BOTH THE GFS AND NAM/WRF
SOUNDINGS SHOW LITTLE OMEGA WITH THESE SYSTEMS. MEANWHILE THE RAP
HAS UP TO 5 MICROBARS OF OMEGA CO-LOCATED WITH THE DENDRITIC
GROWTH ZONE. SINCE BOTH SYSTEMS ARE CURRENTLY PRODUCING SOME
FLURRIES OR VERY LIGHT SNOW...WENT MORE TOWARD THE RAP AND
INTRODUCED SOME SCATTERED FLURRIES FOR THIS AFTERNOON NORTHWEST OF
SAINT ANSGAR IOWA TO WISCONSIN RAPIDS LINE.
ON TUESDAY NIGHT AND WEDNESDAY...THE MODELS CONTINUE TO SHOW THAT
A LOW PRESSURE SYSTEM WILL MOVE ALONG THE ARCTIC COLD FRONT TO OUR
NORTH. AS THE WAVE APPROACHES...THE CLOUDS WILL INCREASE OVERNIGHT
AND TEMPERATURES WILL SLOWLY RISE. LIKE THE PAST COUPLE OF
DAYS...THE MODELS CONTINUE TO SHOW THAT THERE WILL BE ENOUGH
MOISTURE FOR SOME PRECIPITATION TO DEVELOP ALONG AND NORTH OF THE
INTERSTATE 90 CORRIDOR OVERNIGHT TUESDAY AND WEDNESDAY MORNING.
HOWEVER SOUNDINGS CONTINUE TO STRUGGLE ON WHETHER THERE WILL BE
ICE CRYSTAL SEEDING OR NOT. IN MANY CASES...WHERE THEY SHOW THE
LACK OF ICE...THERE IS NO PRECIPITATION. SINCE THERE IS NO CLEAR
SIGNAL...JUST KEPT THE PRECIPITATION IN THE FORM OF SNOW FOR NOW.
HOWEVER A BIT CONCERNED THAT THERE MAY BE SOME LIGHT FREEZING
DRIZZLE ON THE SOUTHERN PERIPHERY OF THE PRECIPITATION.
ANOTHER CONCERN ON WEDNESDAY IS THE TEMPERATURES...THE NAM/WRF HAS
WAY TOO MUCH SNOW COVER IN IT. THIS MODEL SHOWED 1 TO 2 INCHES OF
SNOW ON THE GROUND ACROSS NORTHEAST IOWA AND SOUTHEAST
MINNESOTA...AND 2 TO 5 INCHES OF SNOW ACROSS WESTERN WISCONSIN.
COOPERATIVE REPORTS AND NOHRSC SHOW THAT WITH THE EXCEPTION OF AN
INCH AT MEDFORD WISCONSIN...MUCH OF THE AREA IS SNOW FREE. DUE TO
THIS...THE NAM/WRF TEMPERATURES ARE WAY TOO COLD. TYPICALLY...AT
LA CROSSE THE MID-JANUARY MAXIMUM TEMPERATURES AVERAGE 10 DEGREES
WARMER THAN THE LONG TERM AVERAGE /24.7 DEGREES AT KLSE/ WHEN
THERE IS NO SNOW ON THE GROUND. THIS FITS IN WELL WITH A BLEND OF
THE GFS/ECMWF/GEM. WOULD NOT BE SURPRISED TO SEE SOME LOWER 40S
ACROSS SOUTHWEST WISCONSIN AND NORTHEAST IOWA.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
322 AM CST MON JAN 14 2013
ON THURSDAY AND THURSDAY NIGHT...THE 14.00Z MODELS CONTINUE TO
STRUGGLE ON HOW FAR SOUTH THE ARCTIC FRONT WILL GET. THE GFS HAS
THIS FRONT DROPPING SOUTH OF THE FORECAST AREA. MEANWHILE THE
NAM/WRF KEEPS THIS FRONT NORTH OF THE FORECAST AREA. THIS IS DUE
TO ANOTHER LOW PRESSURE SYSTEM QUICKLY FOLLOWING THE LOW THAT
PASSES TO THE NORTH OF THE AREA ON TUESDAY NIGHT AND WEDNESDAY.
MEANWHILE THE ECMWF IS A GOOD COMPROMISE BETWEEN THE TWO AND IT
HAS THIS FRONT ONLY GETTING AS FAR SOUTH AS THE INTERSTATE 94
CORRIDOR. DUE TO THESE DIFFERENCES...THERE IS LOWER THAN USUAL
CONFIDENCE IN THE TEMPERATURES. EVEN THE SNOWFALL FORECAST IS
UNCERTAIN DUE TO THE VARIOUS TIMING OF THE WAVES AND THE PLACEMENT
OF THE FRONT /THE SNOW WILL BE MAINLY CONFINED NORTH OF THIS
FRONT/.
ON FRIDAY...THE MODELS CONTINUE TO SHOW THAT A LOW PRESSURE AREA
WILL BE PASSING NORTH OF THE AREA. THE COMBINATION OF SOUTHWEST
WINDS AND SUNSHINE WILL ALLOW TEMPERATURES TO ONCE AGAIN WARM INTO
THE 30S AND LOWER 40S. THE ECMWF EVEN SUGGESTS LOWER AND MID 40S.
SINCE THIS HAS BEEN A CONSISTENT SIGNAL...RAISED THE ALL BLEND
TEMPERATURES BY ABOUT 5 DEGREES.
ON SUNDAY...THE MODELS CONTINUE TO STRUGGLE ON HOW FAR SOUTH THE
ARCTIC FRONT WILL SAG SOUTHWARD INTO THE AREA. A COUPLE OF DAYS
AGO THE ECMWF CONSISTENTLY SHOWED THAT THIS FRONT WOULD MOVE WELL
SOUTH OF THE AREA. THE 13.12Z ECMWF BACKED AWAY FROM THIS
SOLUTION...AND THE 14.00Z ECMWF HAS RETURNED BACK TO ITS COLDER
SOLUTION. SINCE THERE IS SOME UNCERTAINTY ON WHERE THIS FRONT WILL
BE LOCATED AND CONCERN ABOUT HOW MUCH MODERATION MAY TAKE PLACE
WITH THE LACK OF SNOW ACROSS THE AREA...JUST STAYED WITH THE ALL
BLEND FORECAST FOR NOW.
&&
.AVIATION...TODAY AND TONIGHT
515 AM CST MON JAN 14 2013
FOG PRODUCT OFF THE IR SATELLITE IS SHOWING A PATCH OF MVFR CLOUDS
MOVING EAST ACROSS SOUTHERN MINNESOTA. TIMING THESE CLOUDS OFF THE
SATELLITE...IT LOOKS LIKE THEY SHOULD BE INTO KRST AROUND 12Z AND
BY MID MORNING FOR KLSE. THEY SHOULD THEN LAST ABOUT 6 HOURS
BEFORE MOVING OFF TO THE EAST. AS WITH THE PAST FEW DAYS...SOME
FLURRIES WILL LIKELY OCCUR WITH THE CLOUDS BUT NO VISIBILITY
RESTRICTIONS ARE EXPECTED. A FEW CLOUDS MAY LINGER THROUGH THE
AFTERNOON BEHIND THE MAIN PATCH OF CLOUDS...BUT BY EVENING AND FOR
THE OVERNIGHT HOURS...THE 14.06Z NAM BUFKIT SOUNDING INDICATE
SKIES SHOULD BE CLEAR WITH VFR CONDITIONS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
322 AM CST MON JAN 14 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1015 AM PST MON JAN 14 2013
...ONE MORE ROUND OF COOL TEMPERATURES EXPECTED...
.DISCUSSION...AS OF 9:35 AM PST MONDAY...TEMPEARTURES ENDED UP
COLD IN MANY SPOTS ACROSS OUR AREA...HOWEVER THE WIND CAME UP MORE
THAN FORECAST FOR PARTS OF THE BAY AND THE NORTH BAY. THIS
PREVENTED SOME LOCATIONS FROM DROPPING AS LOW AS THEY WERE SUNDAY
MORNING.
WIDESPREAD SUNSHINE CAN BE EXPECTED TODAY WITH A FEW DEGREES OF
WARMING COMPARED TO YESTERDAY. GENERALLY LOW TO MID 50S INSTEAD OF
UPPER 40S TO LOWER 50S WHICH WE SAW FOR SUNDAY`S HIGHS.
TONIGHT WILL BE THE COOLEST NIGHT FOR THE NEXT SEVEN DAYS AS A
RIDGE OF HIGH PRESSURE BUILDS BACK TO OUR AREA AND HELPS TO PUSH
TEMPERATURES TO ABOVE NORMAL READINGS FOR THE SECOND HALF OF THE
WEEK. TONIGHT DUE TO FAIRLY LIGHT WINDS AND CLEAR SKIES WE WILL
SEE MOST LOCATIONS BACK IN THE 30S WITH A FEW 20S STILL EXPECTED
FOR PARTS OF THE SOUTHERN SANTA CLARA VALLEY DOWN THROUGH THE
SOUTHERN SALINAS VALLEY. WILL PROBABLY ISSUE ANOTHER FREEZE
WARNING FOR THOSE LOCATIONS. WILL PROBABLY DO A MINOR UPDATE TO
LOWS TONIGHT AS A FEW SHORELINE LOCATIONS LOOK TO BE A BIT TOO
COOL.
.PREVIOUS DISCUSSION...HAVE CANCELLED THE FROST
ADVISORY FOR SAN FRANCISCO AND THE FREEZE WARNING FOR THE SAN
FRANCISCO SHORELINE. THERE HAS BEEN ENOUGH WIND TO KEEP THE
ATMOSPHERE MIXED...SO WHILE THE DEW PTS ARE VERY LOW TEMPERATURES
WILL REMAIN A BIT WARMER THAN EXPECTED. HAVE KEPT THE FREEZE
WARNING GOING TO 9 AM FOR THE INLAND VALLEYS OF THE DISTRICT AS
WELL AS THE SANTA CRUZ/MONTEREY COASTLINE. THE FREEZE WARNING FOR
THE NORTH BAY VALLEYS AND THE EAST BAY VALLEYS IS MARGINAL...BUT
IF THE WIND DIES OFF...TEMPERATURES WILL DROP RAPIDLY IN THE VERY
DRY AIRMASS. THE HRRR MODEL AND THE 00Z WRF BOTH ARE FORECASTING
LIGHT SFC WINDS THIS MORNING...SO WE WILL SEE HOW THIS PANS OUT.
DRY WEATHER WILL BE THE RULE FOR THE UPCOMING WEEK. A STRONG
RIDGE...CLEARLY SEEN ON WATER VAPOR IMAGERY IS CENTERED AROUND
140W...WITH THE RIDGE REACHING INTO ALASKA. INTERESTING TO NOTE
HOW FAR NORTH WARM AIR IS BEING ADVECTED INTO ALASKA...FAIRBANKS
IS CURRENTLY A (RELATIVELY) BALMY 28 DEGREES...WHEREAS THE AVERAGE
LOW IS -14 DEGREES! IN FACT...SAN MARTIN (BETWEEN MORGAN HILL AND
GILROY) IS THE SAME TEMPERATURE AS FAIRBANKS AT THIS TIME...VERY
RARELY SEEN IN THE MIDDLE OF JANUARY!
THE RIDGE WILL SLOWLY EDGE EAST...TO A POSITION ALONG THE COAST BY
THURSDAY...THEN REMAIN OVER THE WEST COAST RIGHT THROUGH THE
WEEKEND. AFTER ANOTHER COLD NIGHT TONIGHT...DEPENDING ON THE
WIND...TEMPERATURES WILL SLOWLY WARM THE REMAINDER OF THE WEEK AND
INTO THE WEEKEND. BOTH THE GFS AND ECMWF BEGIN TO BREAK DOWN THE
RIDGE BY THE MIDDLE OF NEXT WEEK (JANUARY 23).
&&
.AVIATION...AS OF 10:15 AM PST MONDAY...CLEAR SKIES AND OFFSHORE
FLOW WILL CONTINUE ACROSS AREA TERMINALS TODAY AS HIGH PRESSURE
CONTINUES TO BUILD INTO THE GREAT BASIN. THE DRY AIRMASS WILL
MAINTAIN VFR CONDITIONS THROUGH THE FORECAST PERIOD. HIGH
CONFIDENCE.
VICINITY OF KSFO...VFR CONDITIONS EXPECTED THROUGH THE FORECAST
PERIOD. EASTERLY WINDS WILL CONTINUE THROUGH EARLY THIS MORNING
BECOMING VARIABLE IN THE AFTERNOON. LIGHT OFFSHORE FLOW EXPECTED
OVERNIGHT. MODERATE CONFIDENCE IN REGARDS TO WINDS.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR CONDITIONS EXPECTED THROUGH THE
FORECAST PERIOD. OFFSHORE FLOW WILL BECOME VARIABLE THIS AFTERNOON
WITH EASTERLY WINDS ANTICIPATED TO RETURN TONIGHT.
&&
.CLIMATE...HERE ARE THE RECORD LOW TEMPERATURES FOR JANUARY 14TH
AT SELECTED LOCATIONS...
SAN FRANCISCO BAY AREA
.LOCATION....................JAN 14
SANTA ROSA.................21/1963
KENTFIELD..................25/1949
SAN RAFAEL.................28/2007
NAPA.......................24/1963
SAN FRANCISCO..............29/1888
SFO........................31/1963
OAKLAND....................33/2007
OAKLAND AIRPORT............28/2007
RICHMOND...................31/1955
LIVERMORE..................21/1963
MOUNTAIN VIEW..............28/2007
SAN JOSE...................28/1997
GILROY.....................19/1963
MONTEREY BAY AREA
.LOCATION....................JAN 14
MONTEREY...................30/1997
SANTA CRUZ.................22/1963
SALINAS....................24/2007
SALINAS AIRPORT............25/2007
KING CITY..................17/2007
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...NONE.
$$
PUBLIC FORECAST: STROBIN
AVIATION/MARINE: CW
CLIMATE: HENDERSON/BELL
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
941 AM PST MON JAN 14 2013
...ONE MORE ROUND OF COOL TEMPERATURES EXPECTED...
.DISCUSSION...AS OF 9:35 AM PST MONDAY...TEMPEARTURES ENDED UP
COLD IN MANY SPOTS ACROSS OUR AREA...HOWEVER THE WIND CAME UP MORE
THAN FORECAST FOR PARTS OF THE BAY AND THE NORTH BAY. THIS
PREVENTED SOME LOCATIONS FROM DROPPING AS LOW AS THEY WERE SUNDAY
MORNING.
WIDESPREAD SUNSHINE CAN BE EXPECTED TODAY WITH A FEW DEGREES OF
WARMING COMPARED TO YESTERDAY. GENERALLY LOW TO MID 50S INSTEAD OF
UPPER 40S TO LOWER 50S WHICH WE SAW FOR SUNDAY`S HIGHS.
TONIGHT WILL BE THE COOLEST NIGHT FOR THE NEXT SEVEN DAYS AS A
RIDGE OF HIGH PRESSURE BUILDS BACK TO OUR AREA AND HELPS TO PUSH
TEMPERATURES TO ABOVE NORMAL READINGS FOR THE SECOND HALF OF THE
WEEK. TONIGHT DUE TO FAIRLY LIGHT WINDS AND CLEAR SKIES WE WILL
SEE MOST LOCATIONS BACK IN THE 30S WITH A FEW 20S STILL EXPECTED
FOR PARTS OF THE SOUTHERN SANTA CLARA VALLEY DOWN THROUGH THE
SOUTHERN SALINAS VALLEY. WILL PROBABLY ISSUE ANOTHER FREEZE
WARNING FOR THOSE LOCATIONS. WILL PROBABLY DO A MINOR UPDATE TO
LOWS TONIGHT AS A FEW SHORELINE LOCATIONS LOOK TO BE A BIT TOO
COOL.
.PREVIOUS DISCUSSION...HAVE CANCELLED THE FROST
ADVISORY FOR SAN FRANCISCO AND THE FREEZE WARNING FOR THE SAN
FRANCISCO SHORELINE. THERE HAS BEEN ENOUGH WIND TO KEEP THE
ATMOSPHERE MIXED...SO WHILE THE DEW PTS ARE VERY LOW TEMPERATURES
WILL REMAIN A BIT WARMER THAN EXPECTED. HAVE KEPT THE FREEZE
WARNING GOING TO 9 AM FOR THE INLAND VALLEYS OF THE DISTRICT AS
WELL AS THE SANTA CRUZ/MONTEREY COASTLINE. THE FREEZE WARNING FOR
THE NORTH BAY VALLEYS AND THE EAST BAY VALLEYS IS MARGINAL...BUT
IF THE WIND DIES OFF...TEMPERATURES WILL DROP RAPIDLY IN THE VERY
DRY AIRMASS. THE HRRR MODEL AND THE 00Z WRF BOTH ARE FORECASTING
LIGHT SFC WINDS THIS MORNING...SO WE WILL SEE HOW THIS PANS OUT.
DRY WEATHER WILL BE THE RULE FOR THE UPCOMING WEEK. A STRONG
RIDGE...CLEARLY SEEN ON WATER VAPOR IMAGERY IS CENTERED AROUND
140W...WITH THE RIDGE REACHING INTO ALASKA. INTERESTING TO NOTE
HOW FAR NORTH WARM AIR IS BEING ADVECTED INTO ALASKA...FAIRBANKS
IS CURRENTLY A (RELATIVELY) BALMY 28 DEGREES...WHEREAS THE AVERAGE
LOW IS -14 DEGREES! IN FACT...SAN MARTIN (BETWEEN MORGAN HILL AND
GILROY) IS THE SAME TEMPERATURE AS FAIRBANKS AT THIS TIME...VERY
RARELY SEEN IN THE MIDDLE OF JANUARY!
THE RIDGE WILL SLOWLY EDGE EAST...TO A POSITION ALONG THE COAST BY
THURSDAY...THEN REMAIN OVER THE WEST COAST RIGHT THROUGH THE
WEEKEND. AFTER ANOTHER COLD NIGHT TONIGHT...DEPENDING ON THE
WIND...TEMPERATURES WILL SLOWLY WARM THE REMAINDER OF THE WEEK AND
INTO THE WEEKEND. BOTH THE GFS AND ECMWF BEGIN TO BREAK DOWN THE
RIDGE BY THE MIDDLE OF NEXT WEEK (JANUARY 23).
&&
.AVIATION...AS OF 3:15 AM PST MONDAY...VERY DRY AIRMASS IN PLACE
THIS MORNING WITH CLEAR SKIES AND VFR CONDITIONS. CURRENT TAF
PACKAGE WILL CONTINUE VFR THROUGH THE FORECAST PERIOD. ONLY TRICKY
PART ARE THE EASTERLY WINDS...ESP AROUND SAN FRANCISCO BAY. CONF HIGH.
VICINITY OF KSFO...VFR CONDITIONS. WINDS AS OF 11Z ARE SE AROUND
THE BAY. WILL KEEP SE PREVAILING...BUT MODEL GUIDANCE SUGGESTS A
NE FLOW AROUND 10 KT LATER THIS MORNING. CONF IS MARGINAL AND WILL
LEAVE THE NE FLOW OUT FOR NOW. WILL MONITOR AND AMEND SFO IF
NEEDED. OTHERWISE...NW FLOW LATER TODAY.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR CONDITIONS.
&&
.CLIMATE...HERE ARE THE RECORD LOW TEMPERATURES FOR JANUARY 14TH
AT SELECTED LOCATIONS...
SAN FRANCISCO BAY AREA
.LOCATION....................JAN 14
SANTA ROSA.................21/1963
KENTFIELD..................25/1949
SAN RAFAEL.................28/2007
NAPA.......................24/1963
SAN FRANCISCO..............29/1888
SFO........................31/1963
OAKLAND....................33/2007
OAKLAND AIRPORT............28/2007
RICHMOND...................31/1955
LIVERMORE..................21/1963
MOUNTAIN VIEW..............28/2007
SAN JOSE...................28/1997
GILROY.....................19/1963
MONTEREY BAY AREA
.LOCATION....................JAN 14
MONTEREY...................30/1997
SANTA CRUZ.................22/1963
SALINAS....................24/2007
SALINAS AIRPORT............25/2007
KING CITY..................17/2007
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...NONE.
$$
PUBLIC FORECAST: STROBIN
AVIATION/MARINE: MM
CLIMATE: HENDERSON/BELL
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
355 PM MST MON JAN 14 2013
.SHORT TERM...ELONGATED UPPER TROUGH CURRENTLY MOVING ACROSS
STATE. LATEST RUC QG VERTICAL VELOCITY ANALYSIS SHOWING SOME
LINGERING MID LEVEL ASCENT ACROSSS FAR EASTERN PLAINS. CURRENT
SURFACE OBS AND WEB CAMS DO NOT SHOW SNOW OVER THE AREA THOUGH
LATEST SATELLITE INDICATE A DECENT BATCH OF LOW CLOUDS. ACROSS
MOUNTAINS...WEB CAMS SHOW LIGHT SNOW ALONG THE CONTINENTAL DIVIDE
AND PERHAPS OVER THE GORE AND PARK RANGES OF WESTERN JACKSON
COUNTY. MODELS SHOW THE ASCENT MOVING INTO KANSAS DURING THE
EVENING...SHOULD SEE ANY LINGERING SNOW ACROSS THE PLAINS ENDING
AT THAT TIME. MOISTURE DOES INCREASE OVER MOUNTAINS ON BACK SIDE
OF TROUGH OVERNIGHT...SHOULD SEE SNOW CHANCES INCREASE
PARTICULARLY ZONE 31. WINDS LOOK TO INCREASE AS WELL OVER THE
RIDGES WHICH SHOULD HELP MODERATE THE TEMPERATURES IN AND NEAR
FOOTHILLS. WIND CHILL READINGS TO BE WELL BELOW ZERO...BUT SHOULD
REMAIN BELOW WARNING CRITERIA. OTHERWISE...A COLD NIGHT IS
EXPECTED WITH TEMPERATURES SIMILAR TO THIS MORNINGS READINGS. ON
TUESDAY...THE TROUGH WILL BE IN KANSAS BY 18Z WITH NORTHERLY FLOW
ALOFT OVER COLORADO. THIS SHOULD CONTINUE TO PROVIDE A CHANCE OF
SNOW TO THE MOUNTAINS... MAINLY ZONES 31 AND 33. SNOW AMOUNTS TO
REMAIN LIGHT. ACROSS PLAINS...DRY CONDITIONS TO PREVAIL WITH A
GRADUAL INCREASE IN MID LEVEL CLOUDS. GRADUAL WARMING TREND IS
EXPECTED AS WARM AIR ADVECTS INTO AREA. HOWEVER...INVERSIONS WILL
LIMIT WARMUP IN MOUNTAIN VALLEYS AND LOW LYING AREAS OF THE
PLAINS. ALSO MID LEVEL CLOUDS WILL HINDER WARMUP. CURRENT
TEMPERATURE GRIDS LOOK REASONABLE.
.LONG TERM...THE STRONG NORTH-NORTHEASTERLY FLOW ALOFT IS ON THE
DECREASE TUESDAY NIGHT. ON WEDNESDAY...THE FLOW ALOFT CONTINUES
TO WEAKEN AND BECOMES NORTHWESTERLY. VERY WEAK WEST-NORTHWESTERLY
FLOW ALOFT IS PROGGED WEDNESDAY NIGHT THROUGH THURSDAY NIGHT.
THERE IS BENIGN SYNOPTIC SCALE ENERGY PROGGED ON THE QG VERTICAL
VELOCITY FIELDS THROUGH THE FIVE PERIODS. THE LEVEL FLOW WILL
LIKELY BE A MIX OF NORMAL DIURNAL TRENDS WITH SOME NORTHWESTERLY
DOWNSLOPING THROWN IN TUESDAY NIGHT INTO WEDNESDAY EVENING.
NORMALS PATTERNS ARE LIKELY BY THURSDAY AND THURSDAY NIGHT. FOR
MOISTURE...IT IS PRETTY DEEP TUESDAY EVENING...THEN MOISTURE
DECREASES TOWARDS WEDNESDAY MORNING. FROM WEDNESDAY THROUGH
THURSDAY NIGHT THERE IS VERY LITTLE MOISTURE OVER THE CWA. THERE
IS A TAD OF MEASURABLE SNOWFALL PROGGED ON THE QPF FIELDS TUESDAY
EVENING...THEN NOTHING THROUGH THE REST OF THE PERIODS. FOR POPS
WILL GO WITH 20-50%S FOR THE MOUNTAINS TUESDAY NIGHT...AND 5-20%S
FOR THE PLAINS. FROM WEDNESDAY ONWARD NO POPS. FOR TEMPERATURES
...WEDNESDAY`S HIGHS ARE UP 7-9 C FROM TUESDAY`S. THURSDAY`S HIGHS
ARE SIMILAR TO WEDNESDAY`S. FOR THE LATER DAYS...FRIDAY THROUGH
MONDAY...THE MEDIUM RANGE MODELS KEEP THE FORECAST AREA
IN...MOSTLY...WEAK NORTHWESTERLY FLOW ALOFT ALL FOUR DAYS. A MEAN
TROUGH EAST OF THE CWA GETS A LITTLE CLOSER TO THE CWA...COMPARED
TO PREVIOUS RUNS. THE GFS BRINGS A COLDER AIRMASS INTO THE CWA
SATURDAY AND SUNDAY...THE ECMWF DOES NOT. BOTH MODELS KEEP THE CWA
DRY.
&&
.AVIATION...CEILINGS HAVE SCATTERED OUT AT DEN THOUGH SOME HAZE
STILL IN THE AREA. VFR CONDITIONS TO PREVAIL WITH UNLIMITED
CEILINGS. LIGHT NORTHERLY WINDS TO BECOME SOUTHERLY AS DRAINAGE
PATTERN DEVELOPS. ANY FOG THAT DEVELOPS SHOULD BE CONFINED TO THE
LOW LYING AREAS IN WELD COUNTY. ON TUESDAY...WINDS TO BECOME
NORTHWEST WITH SPEEDS LESS THAN 8 KTS. GRADUAL INCREASE IN MID
LEVEL CLOUDS WITH CEILINGS ABOVE 10000 FEET.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
150 PM EST MON JAN 14 2013
.SYNOPSIS (REST OF TODAY THROUGH TUESDAY)...
18Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A CONTINUED HIGHLY
AMPLIFIED UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS. PATTERN IS
DOMINATED BY A LARGE AND IMPRESSIVE LONGWAVE TROUGH COVERING ALMOST
THE ENTIRE CONUS. THE LAST DOMAIN OF THE ONCE PROMINENT UPPER RIDGE
ALONG THE EAST COAST IS ACROSS THE FAR SOUTHEASTERN STATES.
LUCKILY...THIS INCLUDES US AND WILL ALLOW OUR GENERALLY DRY AND WARM
WEATHER TO CONTINUE FOR ANOTHER COUPLE OF DAYS.
UPPER LEVEL JET AND HIGH LEVEL MOISTURE AXIS IS LOCATED WELL OFF TO
OUR NORTHWEST THIS AFTERNOON...AND HENCE WE ARE NOT SEEING THE HIGH
LEVEL CIRRUS COMPARED TO WHAT OCCURRED ON SUNDAY. HOWEVER...SIMILAR
TO PREVIOUS DAYS...WE HAVE SEEN THE DEVELOPMENT OF A SCT-BKN SHALLOW
CU FIELD WITHIN THE SOUTHEAST LOW LEVEL FLOW.
&&
.SHORT TERM (TONIGHT THROUGH WEDNESDAY NIGHT)...
TONIGHT THROUGH TUESDAY NIGHT...
MORE OF THE SAME FOR TONIGHT INTO TUESDAY AS THE STACKED RIDGING
HOLDS ON JUST A LITTLE BIT LONGER. STATIC SYNOPTIC PATTERNS
GENERALLY YIELD STATIC WEATHER. THIS FORECAST WILL REFLECT THAT
PHILOSOPHY WITH SOME PATCHY FOG AND LOW CLOUDS DURING THE LATE NIGHT
/ EARLY MORNING HOURS OF TUESDAY...THEN HAVING ANY FOG BURN OFF BY
AROUND 900 AM. AFTERNOON TEMPS WILL CLIMB TO WITHIN A FEW DEGREES OF
80 INLAND...AND A FEW DEGREES COOLER AT THE BEACHES WITH AN ONSHORE
AFTERNOON BREEZE. AREAS OF EARLY MORNING LOW CLOUDS WILL BURN OFF
QUICKLY AND BE REPLACED A FEW HOURS LATER BY ANOTHER SCT-BKN LOW
LEVEL CU FIELD.
WEDNESDAY/WEDNESDAY NIGHT...
THE APPROACH OF A SERIES OF UPPER LEVEL IMPULSES WILL FINALLY BEGIN
TO PUSH THE UPPER RIDGE TO THE EAST OF THE REGION LATER WEDNESDAY
AND WEDNESDAY NIGHT ALONG WITH A SLOW WEAKENING OF THE SURFACE
RIDGE. OVERALL THE WEATHER FOR WEDNESDAY WILL STILL BE GENERALLY
FAIR AND WARM...BUT CHANGES TO THIS STATIC PATTERN WILL NOT BE FAR
AWAY...AND BE ON THE APPROACH. INITIAL PUSH SYNOPTIC PUSH ON
WEDNESDAY WILL FAIL TO PUSH THE FRONT THROUGH OUR REGION...AND WILL
STALL IT JUST TO OUR NORTH. THE NEXT STRONGER PIECE OF ENERGY MOVING
ALONG THE NORTHERN GULF COAST WILL HOWEVER DO THE TRICK AND PROPEL
THE BOUNDARY THROUGH THE AREA THURSDAY AND/OR THURSDAY NIGHT.
&&
.LONG TERM (THURSDAY THROUGH SUNDAY)...
U/L LOW OVER THE SOUTHERN PLAINS WILL OPEN UP AND LIFT NORTHEAST
ACROSS THE LOWER MISSISSIPPI VALLEY AND SOUTHEAST U.S. THURSDAY. AN
ASSOCIATED COLD FRONT WILL PUSH EAST AND APPROACH WEST CENTRAL
FLORIDA LATE THURSDAY AND THURSDAY NIGHT. MAIN U/L ENERGY WILL
REMAIN WELL NORTH OF THE REGION WITH ONLY A CHANCE OF SHOWERS WITH
THE FRONT. COOLER AIR WILL ADVECT OVER THE FORECAST AREA THURSDAY
NIGHT AND FRIDAY. THE COLD FRONT WILL STALL ACROSS SOUTH FLORIDA AS
IT BECOMES PARALLEL TO THE U/L FLOW FRIDAY AND FRIDAY NIGHT. THIS
WILL KEEP SKIES MOSTLY CLOUDY ACROSS THE REGION WITH A SLIGHT CHANCE
OF A SHOWER. THE FRONT WILL GRADUALLY RETURN NORTH AS A WARM FRONT
SATURDAY WITH A WEAK SURFACE LOW POSSIBLY DEVELOPING ALONG THE
FRONTAL BOUNDARY EAST OF FLORIDA SUNDAY. THIS WILL CONTINUE THE
MOSTLY CLOUDY SKIES AND A SLIGHT CHANCE OF SHOWERS INTO EARLY
SATURDAY...WITH DECREASING CLOUDINESS SATURDAY AS THE SURFACE LOW
LIFTS NORTHEAST OF THE AREA.
&&
.AVIATION...
VFR FOR THE REST OF TODAY WITH SOME LOCAL CEILINGS AROUND 4000 FEET
AT TIMES. FOG DEVELOPS AGAIN OVERNIGHT BUT THINK MOST TERMINALS STAY
VFR. SOME IFR OR EVEN LIFR POSSIBLE 09Z TO 13Z TUESDAY AT PGD AND
LAL.
&&
.MARINE...
HIGH PRESSURE NORTH OF THE BAHAMAS WILL CONTINUE TO RIDGE BACK TO
THE WEST ACROSS THE FLORIDA PENINSULA AND EASTERN GULF OF MEXICO
THROUGH WEDNESDAY. A COLD FRONT WILL THEN CROSS THE FORECAST WATERS
DURING THURSDAY WITH A WIND SHIFT TO THE NORTH IN ITS WAKE BY
THURSDAY NIGHT AND FRIDAY. A PERIOD OF CAUTIONARY TO ADVISORY LEVEL
WINDS AND SEAS WILL ALSO BE POSSIBLE IN THE WAKE OF THIS FRONT.
&&
.FIRE WEATHER...
HIGH PRESSURE WILL CONTINUE TO DOMINATE THE LOCAL WEATHER THROUGH
THE MIDDLE OF THE WEEK. DAYTIME HIGH TEMPERATURES WILL REMAIN ABOVE
NORMAL...HOWEVER PLENTY OF LOW LEVEL MOISTURE WILL PREVENT ANY
SIGNIFICANT FIRE WEATHER CONCERNS. A COLD FRONT WILL CROSS THE AREA
LATE IN THE WEEK WITH CHANCES FOR A FEW SHOWERS AND FOLLOWED BY A
MORE SEASONABLE AIRMASS BY THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 64 79 64 78 / 0 0 0 0
FMY 62 81 62 82 / 0 0 0 10
GIF 57 81 58 82 / 0 0 0 0
SRQ 61 78 59 77 / 0 0 0 0
BKV 54 80 54 81 / 0 0 0 10
SPG 65 77 64 78 / 0 0 0 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
AVIATION...JILLSON
LONG TERM...OGLESBY
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
322 PM EST MON JAN 14 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.
&&
.SYNOPSIS...
ISSUED AT 320 PM EST MON JAN 14 2013
QUIET WEATHER IS EXPECTED FOR MUCH OF THE PERIOD WITH
TEMPERATURES RETURNING TO NORMAL FOR THIS TIME OF YEAR UNDER HIGH
PRESSURE. BY THE END OF THE LONG TERM THOUGH A CLIPPER SYSTEM COULD
MOVE THROUGH BRINGING CHANCES FOR SNOW AND COLDER TEMPERATURES WITH
IT.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 320 PM EST MON JAN 14 2013
CURRENTLY RADAR MOSAIC SHOWS SOME WEAK ECHOES TO THE SOUTH AND WEST
THAT ARE MOVING NORTHEAST...BUT NO PRECIPITATION IS BEING REPORTED
AT THE GROUND UNDER ANY OF THESE ECHOES AND WITH VERY DRY AIR ALOFT
IN THE SOUNDINGS DO NOT EXPECT TO SEE ANY OF THIS REACH THE GROUND.
SATELLITE SHOWS MOSTLY CLOUDY SKIES ACROSS THE AREA AND TEMPERATURES
ARE IN THE LOW TO MID 20S WITH LIGHT NORTHERLY WINDS.
HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE WEST DURING THE
OVERNIGHT. COMBINATION OF STRATOCU AND MID LEVEL CLOUDS WILL HAVE
THE AREA STARTING OUT MOSTLY CLOUDY BUT THESE CLOUDS SHOULD THIN AND
SCATTER OUT FROM NORTHWEST TO SOUTHEAST BY MORNING. GUIDANCE
TEMPERATURES WERE A BIT WARMER THAN LOWS WERE LAST NIGHT AND WITH
COLDER SURFACE/925MB/850MB TEMPERATURES AND SIMILAR CLOUD COVER SEE
NO REASON FOR THIS TO BE TRUE. THUS ADJUSTED TEMPERATURES DOWN A FEW
DEGREES FROM GUIDANCE TO BE A DEGREE OR TWO LOWER THAN LAST NIGHT.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 320 PM EST MON JAN 14 2013
QUIET WEATHER IS EXPECTED OVER THE SHORT TERM AS HIGH PRESSURE
REMAINS THE DOMINANT FEATURE OVER CENTRAL INDIANA. AT THIS TIME IT
LOOKS LIKE THE AREA WILL BE IN BETWEEN A LOW PRESSURE SYSTEM COMING
OUT OF THE GULF AND TO VIRGINIA WHILE A CLIPPER MOVES ACROSS THE
GREAT LAKES FROM TUESDAY THROUGH WEDNESDAY NIGHT. THESE SYSTEMS
COULD INCREASE CLOUDS A BIT IN THE SOUTH AND NORTH RESPECTIVELY BUT
THE SURFACE HIGH OVER THE AREA SHOULD KEEP CENTRAL INDIANA DRY. FOR
TEMPERATURES GENERALLY USED A GUIDANCE CONSENSUS WHICH ALLOWED FOR A
LITTLE WARMING TUESDAY THROUGH WEDNESDAY NIGHT WITH SLIGHTLY COOLER
HIGHS ON THURSDAY AFTER THE PASSAGE OF THE CLIPPER TO THE NORTH.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 252 PM EST MON JAN 14 2013
FOCUS OF THE EXTENDED PERIOD REMAINS ON A TRANSITION TO MUCH
COLDER AIR ACROSS THE REGION AS THE POLAR VORTEX DIVES INTO
EASTERN CANADA AND SERVES TO AMPLIFY THE UPPER TROUGH OVER THE
EASTERN PART OF THE COUNTRY.
DRY WEATHER AND LARGELY SEASONABLE TEMPS WILL CONTINUE THROUGH
SATURDAY AS NORTHWEST FLOW ALOFT PERSISTS ACROSS THE OHIO VALLEY.
HIGHS IN THE 30S FRIDAY WILL WARM INTO THE 40S SATURDAY AS BRIEF
WARM ADVECTION DEVELOPS AHEAD OF A STRONG WAVE MOVING INTO THE
GREAT LAKES. MODEL CONSENSUS TRACKS THE SURFACE WAVE TO THE NORTH
OF THE REGION SATURDAY NIGHT...WITH THE MAIN IMPACTS TO CENTRAL
INDIANA BEING AN INCREASE IN WINDS AND A WINDSHIFT AS THE INITIAL
SHOT OF COLDER AIR ADVECTS INTO THE AREA. THIS WILL BE FOLLOWED BY
A CLIPPER-LIKE SYSTEM FOR MONDAY...USHERING IN A REINFORCING AND
COLDER AIRMASS AS A PIECE OF OF THE POLAR VORTEX DIVES INTO THE
GREAT LAKES. WHILE MODELS ARE NOT PICKING UP ON A LOT OF MOISTURE
WITH THE CLIPPER...EXPECT SNOW SHOWERS TO ACCOMPANY THE SYSTEM AND
HAVE INCLUDED CHANCE POPS SUNDAY NIGHT AND MONDAY. 850MB TEMPS
BELOW -20C CONTINUE TO SHOW UP OVER THE FORECAST AREA ON BOTH THE OP
GFS AND ECMWF BY MONDAY/TUESDAY. AT THIS POINT HAVE HIGHS FALLING
INTO THE LOWER/MID 20S BY MONDAY. NOT OUT OF THE QUESTION THAT IF
THESE 850MB TEMPS ARE REALIZED THAT HIGHS COULD CONCEIVABLY BE
EVEN COLDER EARLY NEXT WEEK.
&&
.AVIATION /DISCUSSION FOR THE 14/21Z TAF UPDATE/...
ISSUED AT 316 PM EST MON JAN 14 2013
LOW CLOUDS HAVE SCATTERED AT ALL SITES BUT LAF...AND HAVE UPDATED
TAFS TO REFLECT THIS. PREVIOUS DISCUSSION FOLLOWS.
ISSUED AT 1222 PM EST MON JAN 14 2013
MVFR CEILINGS LIKELY TO PERSIST THROUGH THE AFTERNOON...AND
POSSIBLY TO SOME DEGREE TONIGHT.
THE COMBINATION OF COLD ADVECTION...GOOD LAPSE RATES AND VEERING
N/NE FLOW IN THE LOWER LEVELS HAS ENABLED CEILINGS AROUND 1500FT
TO REDEVELOP AND EXPAND BACK INTO CENTRAL INDIANA EARLY THIS
AFTERNOON. WITH MOISTURE INCREASING A BIT THROUGH THE BOUNDARY
LAYER...EXPECT MVFR CEILINGS TO MAINTAIN TO SOME DEGREE FOR THE
REST OF THE AFTERNOON. IN ADDITION TO THE STRATOCU...FAIRLY DENSE
CANOPY OF MID LEVEL CLOUDS WILL MOVE ACROSS THE OHIO VALLEY IN FAT
SOUTHWEST FLOW ALOFT. NORTHERLY WINDS WILL BE LESS THAN 10KTS
THROUGH SUNSET.
CLOUD FORECAST TONIGHT HAS SOME UNCERTAINTY AS RAP SOUNDINGS
INDICATING SHALLOW LAYER OF LOW LEVEL MOISTURE PERSISTING. WHILE
FLOW THROUGH 925MB WEAKENS...IT REMAINS FROM THE NORTHEAST INTO
THE OVERNIGHT. HAVE INTRODUCED SCATTERED CEILINGS AT 1500FT
TONIGHT AND WILL ADJUST AS NECESSARY. MID LEVEL CLOUDS WILL
CONTINUE TO MOVE ACROSS THE REGION IN THE SOUTHWEST FLOW AS WELL.
SHOULD FINALLY SEE MOSTLY CLEAR SKIES BY TUESDAY MORNING AS CENTER
OF HIGH PRESSURE BUILDS ACROSS THE OHIO VALLEY WITH DEEPER
SUBSIDENCE NOTED IN THE MODEL SOUNDINGS. WINDS WILL VEER TO THE
NORTHEAST AND REMAIN AT 10KTS OR LESS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....RYAN
AVIATION...RYAN/NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
316 PM EST MON JAN 14 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 308 AM EST MON JAN 14 2013
HIGH PRESSURE WILL BUILD FROM THE PLAINS TO THE LOWER GREAT LAKES
AND OHIO VALLEY ALLOWING FOR A DRY FORECAST THROUGH SUNDAY. BELOW
NORMAL TEMPERATURES TO START THE WEEK WILL BECOME SEASONABLE BY
MIDWEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1106 AM EST MON JAN 14 2013
SATELLITE AT 11 AM SHOWS PARTLY CLOUDY SKIES ACROSS MOST OF
CENTRAL INDIANA WITH A BIT MORE CLOUD COVERAGE IN THE NORTHEAST.
EXPECT PARTLY CLOUDY TO BE THE RULE FOR THE REST OF THE DAY. GOING
FORECAST HIGHS IN THE MID 20S TO LOW 30S LOOK RIGHT ON TRACK.
PREVIOUS DISCUSSION FOLLOWS...
MAIN FOCUS TODAY WILL BE ON CLEARING AS STRATOCU DECK WAS CURRENTLY
DROPPING SOUTHEAST ACROSS THE EASTERN HALF OF CENTRAL INDIANA BEHIND
A DEPARTING COLD FRONT ACROSS THE APPALACHIANS.
MODELS IN GOOD AGREEMENT ON PLAINS HIGH PRESSURE BUILDING IN ACROSS
THE FORECAST AREA. MODEL TIME SECTIONS AND SOUNDINGS ARE ALSO SHOWING
THINNING OF THE LOW LEVEL MOISTURE ASSOCIATED WITH THE STRATOCU
DECK...AND SATELLITE TRENDS SUGGEST THEY WILL DEPART TO THE
SOUTHEAST DESPITE WHAT 00Z MOS WAS SUGGESTING. MEANWHILE...UPPER
WAVE IN FAST SOUTHWEST FLOW ALOFT COULD BRING SOME INCREASED CLOUD
COVER LATE TO THE SOUTHEAST COUNTIES. DRY DAY SHOULD ALLOW AREA
CREEKS AND STREAMS TO DROP BELOW FLOOD STAGE AS THEY EMPTY INTO
THE MAIN RIVERS WITH MINOR TO MODERATE FLOODING ON MOST FORECAST
POINTS.
00Z MOS TEMPERATURES AND ALLBLEND MATCH UP PRETTY WELL AND LOOK
REASONABLE CONSIDERING THE NORTHWEST COLD ADVECTION.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 308 AM EST MON JAN 14 2013
MODELS AGREE HIGH PRESSURE AND LIMITED MOISTURE SHOULD ALLOW FOR
LITTLE CLOUD COVER THROUGH THE SHORT TERM. SHOULD ONLY SEE SOME
INCREASE IN CLOUDS SOUTH LATE TUESDAY AS AN INVERTED TROUGH SLIDES
ACROSS THE SOUTHEASTERN STATES AND SOME INCREASE IN CLOUDS NORTH
LATE WEDNESDAY AS A COLD FRONT DROPS SOUTH TO THE LOWER GREAT LAKES.
LOW LEVEL FLOW IS EXPECTED TO VEER TO THE NORTH TONIGHT...NORTHEAST
ON TUESDAY AND SOUTHWEST BY WEDNESDAY. THIS WILL ALLOW TEMPERATURES
TO WARM TO THE MID 30S NORTH AND LOWER 40S SOUTH PER SIMILAR 00Z MOS
AND ALLBLEND BY WEDNESDAY. THE DRY WEATHER WILL ALLOW MINOR TO
MODERATE RIVER FLOODING TO RUN ITS COURSE WITHOUT ANY HITCHES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 252 PM EST MON JAN 14 2013
FOCUS OF THE EXTENDED PERIOD REMAINS ON A TRANSITION TO MUCH
COLDER AIR ACROSS THE REGION AS THE POLAR VORTEX DIVES INTO
EASTERN CANADA AND SERVES TO AMPLIFY THE UPPER TROUGH OVER THE
EASTERN PART OF THE COUNTRY.
DRY WEATHER AND LARGELY SEASONABLE TEMPS WILL CONTINUE THROUGH
SATURDAY AS NORTHWEST FLOW ALOFT PERSISTS ACROSS THE OHIO VALLEY.
HIGHS IN THE 30S FRIDAY WILL WARM INTO THE 40S SATURDAY AS BRIEF
WARM ADVECTION DEVELOPS AHEAD OF A STRONG WAVE MOVING INTO THE
GREAT LAKES. MODEL CONSENSUS TRACKS THE SURFACE WAVE TO THE NORTH
OF THE REGION SATURDAY NIGHT...WITH THE MAIN IMPACTS TO CENTRAL
INDIANA BEING AN INCREASE IN WINDS AND A WINDSHIFT AS THE INITIAL
SHOT OF COLDER AIR ADVECTS INTO THE AREA. THIS WILL BE FOLLOWED BY
A CLIPPER-LIKE SYSTEM FOR MONDAY...USHERING IN A REINFORCING AND
COLDER AIRMASS AS A PIECE OF OF THE POLAR VORTEX DIVES INTO THE
GREAT LAKES. WHILE MODELS ARE NOT PICKING UP ON A LOT OF MOISTURE
WITH THE CLIPPER...EXPECT SNOW SHOWERS TO ACCOMPANY THE SYSTEM AND
HAVE INCLUDED CHANCE POPS SUNDAY NIGHT AND MONDAY. 850MB TEMPS
BELOW -20C CONTINUE TO SHOW UP OVER THE FORECAST AREA ON BOTH THE OP
GFS AND ECMWF BY MONDAY/TUESDAY. AT THIS POINT HAVE HIGHS FALLING
INTO THE LOWER/MID 20S BY MONDAY. NOT OUT OF THE QUESTION THAT IF
THESE 850MB TEMPS ARE REALIZED THAT HIGHS COULD CONCEIVABLY BE
EVEN COLDER EARLY NEXT WEEK.
&&
.AVIATION /DISCUSSION FOR THE 14/21Z TAF UPDATE/...
ISSUED AT 316 PM EST MON JAN 14 2013
LOW CLOUDS HAVE SCATTERED AT ALL SITES BUT LAF...AND HAVE UPDATED
TAFS TO REFLECT THIS. PREVIOUS DISCUSSION FOLLOWS.
ISSUED AT 1222 PM EST MON JAN 14 2013
MVFR CEILINGS LIKELY TO PERSIST THROUGH THE AFTERNOON...AND
POSSIBLY TO SOME DEGREE TONIGHT.
THE COMBINATION OF COLD ADVECTION...GOOD LAPSE RATES AND VEERING
N/NE FLOW IN THE LOWER LEVELS HAS ENABLED CEILINGS AROUND 1500FT
TO REDEVELOP AND EXPAND BACK INTO CENTRAL INDIANA EARLY THIS
AFTERNOON. WITH MOISTURE INCREASING A BIT THROUGH THE BOUNDARY
LAYER...EXPECT MVFR CEILINGS TO MAINTAIN TO SOME DEGREE FOR THE
REST OF THE AFTERNOON. IN ADDITION TO THE STRATOCU...FAIRLY DENSE
CANOPY OF MID LEVEL CLOUDS WILL MOVE ACROSS THE OHIO VALLEY IN FAT
SOUTHWEST FLOW ALOFT. NORTHERLY WINDS WILL BE LESS THAN 10KTS
THROUGH SUNSET.
CLOUD FORECAST TONIGHT HAS SOME UNCERTAINTY AS RAP SOUNDINGS
INDICATING SHALLOW LAYER OF LOW LEVEL MOISTURE PERSISTING. WHILE
FLOW THROUGH 925MB WEAKENS...IT REMAINS FROM THE NORTHEAST INTO
THE OVERNIGHT. HAVE INTRODUCED SCATTERED CEILINGS AT 1500FT
TONIGHT AND WILL ADJUST AS NECESSARY. MID LEVEL CLOUDS WILL
CONTINUE TO MOVE ACROSS THE REGION IN THE SOUTHWEST FLOW AS WELL.
SHOULD FINALLY SEE MOSTLY CLEAR SKIES BY TUESDAY MORNING AS CENTER
OF HIGH PRESSURE BUILDS ACROSS THE OHIO VALLEY WITH DEEPER
SUBSIDENCE NOTED IN THE MODEL SOUNDINGS. WINDS WILL VEER TO THE
NORTHEAST AND REMAIN AT 10KTS OR LESS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...MK/CP
SHORT TERM...MK
LONG TERM....RYAN
AVIATION...RYAN/NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
252 PM EST MON JAN 14 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 308 AM EST MON JAN 14 2013
HIGH PRESSURE WILL BUILD FROM THE PLAINS TO THE LOWER GREAT LAKES
AND OHIO VALLEY ALLOWING FOR A DRY FORECAST THROUGH SUNDAY. BELOW
NORMAL TEMPERATURES TO START THE WEEK WILL BECOME SEASONABLE BY
MIDWEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1106 AM EST MON JAN 14 2013
SATELLITE AT 11 AM SHOWS PARTLY CLOUDY SKIES ACROSS MOST OF
CENTRAL INDIANA WITH A BIT MORE CLOUD COVERAGE IN THE NORTHEAST.
EXPECT PARTLY CLOUDY TO BE THE RULE FOR THE REST OF THE DAY. GOING
FORECAST HIGHS IN THE MID 20S TO LOW 30S LOOK RIGHT ON TRACK.
PREVIOUS DISCUSSION FOLLOWS...
MAIN FOCUS TODAY WILL BE ON CLEARING AS STRATOCU DECK WAS CURRENTLY
DROPPING SOUTHEAST ACROSS THE EASTERN HALF OF CENTRAL INDIANA BEHIND
A DEPARTING COLD FRONT ACROSS THE APPALACHIANS.
MODELS IN GOOD AGREEMENT ON PLAINS HIGH PRESSURE BUILDING IN ACROSS
THE FORECAST AREA. MODEL TIME SECTIONS AND SOUNDINGS ARE ALSO SHOWING
THINNING OF THE LOW LEVEL MOISTURE ASSOCIATED WITH THE STRATOCU
DECK...AND SATELLITE TRENDS SUGGEST THEY WILL DEPART TO THE
SOUTHEAST DESPITE WHAT 00Z MOS WAS SUGGESTING. MEANWHILE...UPPER
WAVE IN FAST SOUTHWEST FLOW ALOFT COULD BRING SOME INCREASED CLOUD
COVER LATE TO THE SOUTHEAST COUNTIES. DRY DAY SHOULD ALLOW AREA
CREEKS AND STREAMS TO DROP BELOW FLOOD STAGE AS THEY EMPTY INTO
THE MAIN RIVERS WITH MINOR TO MODERATE FLOODING ON MOST FORECAST
POINTS.
00Z MOS TEMPERATURES AND ALLBLEND MATCH UP PRETTY WELL AND LOOK
REASONABLE CONSIDERING THE NORTHWEST COLD ADVECTION.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 308 AM EST MON JAN 14 2013
MODELS AGREE HIGH PRESSURE AND LIMITED MOISTURE SHOULD ALLOW FOR
LITTLE CLOUD COVER THROUGH THE SHORT TERM. SHOULD ONLY SEE SOME
INCREASE IN CLOUDS SOUTH LATE TUESDAY AS AN INVERTED TROUGH SLIDES
ACROSS THE SOUTHEASTERN STATES AND SOME INCREASE IN CLOUDS NORTH
LATE WEDNESDAY AS A COLD FRONT DROPS SOUTH TO THE LOWER GREAT LAKES.
LOW LEVEL FLOW IS EXPECTED TO VEER TO THE NORTH TONIGHT...NORTHEAST
ON TUESDAY AND SOUTHWEST BY WEDNESDAY. THIS WILL ALLOW TEMPERATURES
TO WARM TO THE MID 30S NORTH AND LOWER 40S SOUTH PER SIMILAR 00Z MOS
AND ALLBLEND BY WEDNESDAY. THE DRY WEATHER WILL ALLOW MINOR TO
MODERATE RIVER FLOODING TO RUN ITS COURSE WITHOUT ANY HITCHES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 252 PM EST MON JAN 14 2013
FOCUS OF THE EXTENDED PERIOD REMAINS ON A TRANSITION TO MUCH
COLDER AIR ACROSS THE REGION AS THE POLAR VORTEX DIVES INTO
EASTERN CANADA AND SERVES TO AMPLIFY THE UPPER TROUGH OVER THE
EASTERN PART OF THE COUNTRY.
DRY WEATHER AND LARGELY SEASONABLE TEMPS WILL CONTINUE THROUGH
SATURDAY AS NORTHWEST FLOW ALOFT PERSISTS ACROSS THE OHIO VALLEY.
HIGHS IN THE 30S FRIDAY WILL WARM INTO THE 40S SATURDAY AS BRIEF
WARM ADVECTION DEVELOPS AHEAD OF A STRONG WAVE MOVING INTO THE
GREAT LAKES. MODEL CONSENSUS TRACKS THE SURFACE WAVE TO THE NORTH
OF THE REGION SATURDAY NIGHT...WITH THE MAIN IMPACTS TO CENTRAL
INDIANA BEING AN INCREASE IN WINDS AND A WINDSHIFT AS THE INITIAL
SHOT OF COLDER AIR ADVECTS INTO THE AREA. THIS WILL BE FOLLOWED BY
A CLIPPER-LIKE SYSTEM FOR MONDAY...USHERING IN A REINFORCING AND
COLDER AIRMASS AS A PIECE OF OF THE POLAR VORTEX DIVES INTO THE
GREAT LAKES. WHILE MODELS ARE NOT PICKING UP ON A LOT OF MOISTURE
WITH THE CLIPPER...EXPECT SNOW SHOWERS TO ACCOMPANY THE SYSTEM AND
HAVE INCLUDED CHANCE POPS SUNDAY NIGHT AND MONDAY. 850MB TEMPS
BELOW -20C CONTINUE TO SHOW UP OVER THE FORECAST AREA ON BOTH THE OP
GFS AND ECMWF BY MONDAY/TUESDAY. AT THIS POINT HAVE HIGHS FALLING
INTO THE LOWER/MID 20S BY MONDAY. NOT OUT OF THE QUESTION THAT IF
THESE 850MB TEMPS ARE REALIZED THAT HIGHS COULD CONCEIVABLY BE
EVEN COLDER EARLY NEXT WEEK.
&&
.AVIATION /DISCUSSION FOR 141800Z TAF ISSUANCE/...
ISSUED AT 1222 PM EST MON JAN 14 2013
MVFR CEILINGS LIKELY TO PERSIST THROUGH THE AFTERNOON...AND
POSSIBLY TO SOME DEGREE TONIGHT.
THE COMBINATION OF COLD ADVECTION...GOOD LAPSE RATES AND VEERING
N/NE FLOW IN THE LOWER LEVELS HAS ENABLED CEILINGS AROUND 1500FT
TO REDEVELOP AND EXPAND BACK INTO CENTRAL INDIANA EARLY THIS
AFTERNOON. WITH MOISTURE INCREASING A BIT THROUGH THE BOUNDARY
LAYER...EXPECT MVFR CEILINGS TO MAINTAIN TO SOME DEGREE FOR THE
REST OF THE AFTERNOON. IN ADDITION TO THE STRATOCU...FAIRLY DENSE
CANOPY OF MID LEVEL CLOUDS WILL MOVE ACROSS THE OHIO VALLEY IN FAT
SOUTHWEST FLOW ALOFT. NORTHERLY WINDS WILL BE LESS THAN 10KTS
THROUGH SUNSET.
CLOUD FORECAST TONIGHT HAS SOME UNCERTAINTY AS RAP SOUNDINGS
INDICATING SHALLOW LAYER OF LOW LEVEL MOISTURE PERSISTING. WHILE
FLOW THROUGH 925MB WEAKENS...IT REMAINS FROM THE NORTHEAST INTO
THE OVERNIGHT. HAVE INTRODUCED SCATTERED CEILINGS AT 1500FT
TONIGHT AND WILL ADJUST AS NECESSARY. MID LEVEL CLOUDS WILL
CONTINUE TO MOVE ACROSS THE REGION IN THE SOUTHWEST FLOW AS WELL.
SHOULD FINALLY SEE MOSTLY CLEAR SKIES BY TUESDAY MORNING AS CENTER
OF HIGH PRESSURE BUILDS ACROSS THE OHIO VALLEY WITH DEEPER
SUBSIDENCE NOTED IN THE MODEL SOUNDINGS. WINDS WILL VEER TO THE
NORTHEAST AND REMAIN AT 10KTS OR LESS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...MK/CP
SHORT TERM...MK
LONG TERM....RYAN
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1235 PM EST MON JAN 14 2013
.UPDATE...
UPDATE SENT EARLIER TO EXPAND IN TIME AND SPACE CLOUD COVER AND
REINTRODUCE FLURRIES FOR MUCH OF THE AREA INTO EARLY AFTERNOON.
LAKE EFFECT CLOUDS WERE HOLDING STRONG ACROSS MUCH OF THE FORECAST
AREA WITH SEVERAL LOCATIONS REPORTING FLURRY ACTIVITY. NO ACCUMS
ARE EXPECTED SO KEPT THINGS SIMPLE AND WENT WITH SCT FLURRIES INTO
EARLY AFTERNOON WHEN LL FLOW WILL WEAKEN AND DRY AIR BECOME MORE
ENTRAINED. NO MODIFICATIONS TO ANY OTHER PARTS OF THE FORECAST WITH
TEMPS STILL GENERALLY ON TRACK.
&&
.AVIATION...
MVFR CIGS HOLDING AS A RESULT OF LAKE EFFECT CLOUD COVER.
CONDITIONS SHOULD IMPROVE BY LATE AFTERNOON AS DRIER AIR WORKS IN.
TAFS PATCHED UP TO REFLECT THIS WITH VFR CONDITIONS ANTICIPATED
AFTER 00Z AND FOR THE REMAINDER OF THE PERIOD.
&&
.PREV DISCUSSION... /ISSUED 645 AM EST MON JAN 14 2013/
SHORT TERM... /TODAY THROUGH TUESDAY NIGHT/
NMRS MESOGAMMA THERMAL ROLLS CRNTLY BLOSSOMING WSR-88 VCP 31
RETURNS ERLY THIS MORNING...EXTNDG FARTHER SOUTH THAN TYPICAL LAKE
RESPONSE...AT LEAST TO KRCR-WABASH LN. LK MSTR ENHANCEMENT RATHER
MINIMAL GIVEN ONLY LWR TEENS LK/8H THERMAL DIFFERENTIAL ACRS FAR
SRN LK MI. THIN LYR LIFT ON NOSE OF 30-35KT 8H JETLET/SHORTWAVE FM
NRN IL AT 03 UTC. 8H PSUEDOFRONT APPEARS ORTHOGONALLY ALONG
LEADING EDGE OF RAP ANALYZED THIN LYR NEAR SFC/950-900 MB/ FGEN
ZONE LAID OUT SRN LK HUR-SERN FA-SRN IN...WHICH SHOULD QUELL
FLURRIES MENTION BY ABOUT 14 UTC. THIS THE ONLY SENSIBLE WX IN THE
SHORT TERM PD. THEREAFTER...THE DEEP SCOUR OF MSTR BY CP CANADIAN
PLAINS AIRMASS TO CONT TO ERODE RMNG STRATOCU FIELD TDY ON LEADING
EDGE OF 1034MB RIDGE. ANTICIPATE POOR THERMAL RECOVERY THOUGH IN
LIGHT OF SIG AIRMASS EXCHANGE ALONG WITH POTNL INCRS IN CI/CS LTR
THIS AFTN ASSOCD WITH INTENSE ULVL JETSTREAK ON ORDER OF 180-200
KTS LIFTG THROUGH MID MS VLY TO FAR SRN ONT THIS EVE. GOOD POTNL
FOR DECOUPLED BLYR LATE TONIGHT. DOWN TO LWR TEENS/PSBLY LWR
SINGLE DIGITS...SPCLY FAR WRN CWA WITH BEST DURATION FOR LONGWAVE
LOSSES. SLIGHT SFC- 925MB THERMAL MODIFICATION BY DAYBREAK
WED...ALONG WITH INCRSD MIXED BL...WITH CWA ON SERN PERIPHERY OF
RAMPING FLOW ASSOCD WITH HIGH BELTED CLIPPER.
LONG TERM... /WEDNESDAY THROUGH SUNDAY/
A LONGWAVE TROF WILL AMPLIFY OVER EASTERN NORTH AMERICA THIS
PERIOD AS A PRECURSOR OF THE ARRIVAL OF VERY COLD AIR LATE IN THE
PERIOD. THE 500 MB GFS AND CANADIAN ANALOGS...GFS AND CANADIAN
ENSEMBLES AND THE ECMWF ALL SUPPORT THE ESTABLISHMENT OF A MUCH
COLDER PATTERN EARLY NEXT WEEK. AHEAD OF THE AMPLIFYING UPPER
TROF...A WEAKER TROF WILL MOVE ACROSS THE AREA ACCOMPANIED BY A
COLD FRONT WEDNESDAY NIGHT. THERE IS NOT MUCH SUPPORT FOR
PRECIPITATION WITH THIS SYSTEM INCLUDING LAKE EFFECT SNOW.
MOISTURE IS LIMITED AND FORCING IS WEAK. THE MOST UNSTABLE LAKE
EFFECT DELTA T VALUES BEFORE SUNDAY ARE 10 TO 14...BUT WITH AN
UNFAVORABLE FETCH OVER MUCH OF THE PERIOD...KEPT THE FORECAST DRY.
FOR LATE IN THE PERIOD...GUT FEELING HIGHS SUNDAY ARE TOO WARM.
HOWEVER...LEFT HIGHS AROUND 30 MOST AREAS GIVEN THE UNCERTAINTY OF
THE ARRIVAL TIME OF THE FRONT. THE GFS MEAN ENSEMBLE MOS HIGHS
SUNDAY ARE 22 TO 27 WHICH MAY BE ON TRACK. A PERIOD OF LIGHT SNOW
IN THE ARCTIC AIR MAY ALSO EVENTUALLY NEED TO BE ADDED TO THE
FORECAST SUNDAY IF A FASTER FRONTAL PASSAGE PREVAILS. TEMPERATURES
MAY BE STEADY OR SLOWING FALLING SUNDAY. FOR NOW...WENT WITH A
SMALL DIURNAL RISE SUNDAY.
MARINE...
LOOK FOR RAPIDLY INCRSG GRADIENT FLOW AS ULVL TROF SHIFTS GRDLY
EWD INTO WRN GRTLKS BY LATE TUE. MIDWEEK MARINE HEADLINES TO LATER
FOCUS ON NEED FOR NEARSHORE GALE WATCH/WARNING WITH BEST WINDOW IN
THE 12-21 UTC WED TIMEFRAME. ACCELERATION RATE OF FLOW SHOULD
PRECLUDE LEAD IN SC.Y...THOUGH LATER FCSTS TO FINE TUNE AS NEED
BE.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...MURPHY
LONG TERM...SKIPPER
AVIATION...FISHER
UPDATE...FISHER
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1222 PM EST MON JAN 14 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 308 AM EST MON JAN 14 2013
HIGH PRESSURE WILL BUILD FROM THE PLAINS TO THE LOWER GREAT LAKES
AND OHIO VALLEY ALLOWING FOR A DRY FORECAST THROUGH SUNDAY. BELOW
NORMAL TEMPERATURES TO START THE WEEK WILL BECOME SEASONABLE BY
MIDWEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1106 AM EST MON JAN 14 2013
SATELLITE AT 11 AM SHOWS PARTLY CLOUDY SKIES ACROSS MOST OF
CENTRAL INDIANA WITH A BIT MORE CLOUD COVERAGE IN THE NORTHEAST.
EXPECT PARTLY CLOUDY TO BE THE RULE FOR THE REST OF THE DAY. GOING
FORECAST HIGHS IN THE MID 20S TO LOW 30S LOOK RIGHT ON TRACK.
PREVIOUS DISCUSSION FOLLOWS...
MAIN FOCUS TODAY WILL BE ON CLEARING AS STRATOCU DECK WAS CURRENTLY
DROPPING SOUTHEAST ACROSS THE EASTERN HALF OF CENTRAL INDIANA BEHIND
A DEPARTING COLD FRONT ACROSS THE APPALACHIANS.
MODELS IN GOOD AGREEMENT ON PLAINS HIGH PRESSURE BUILDING IN ACROSS
THE FORECAST AREA. MODEL TIME SECTIONS AND SOUNDINGS ARE ALSO SHOWING
THINNING OF THE LOW LEVEL MOISTURE ASSOCIATED WITH THE STRATOCU
DECK...AND SATELLITE TRENDS SUGGEST THEY WILL DEPART TO THE
SOUTHEAST DESPITE WHAT 00Z MOS WAS SUGGESTING. MEANWHILE...UPPER
WAVE IN FAST SOUTHWEST FLOW ALOFT COULD BRING SOME INCREASED CLOUD
COVER LATE TO THE SOUTHEAST COUNTIES. DRY DAY SHOULD ALLOW AREA
CREEKS AND STREAMS TO DROP BELOW FLOOD STAGE AS THEY EMPTY INTO
THE MAIN RIVERS WITH MINOR TO MODERATE FLOODING ON MOST FORECAST
POINTS.
00Z MOS TEMPERATURES AND ALLBLEND MATCH UP PRETTY WELL AND LOOK
REASONABLE CONSIDERING THE NORTHWEST COLD ADVECTION.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 308 AM EST MON JAN 14 2013
MODELS AGREE HIGH PRESSURE AND LIMITED MOISTURE SHOULD ALLOW FOR
LITTLE CLOUD COVER THROUGH THE SHORT TERM. SHOULD ONLY SEE SOME
INCREASE IN CLOUDS SOUTH LATE TUESDAY AS AN INVERTED TROUGH SLIDES
ACROSS THE SOUTHEASTERN STATES AND SOME INCREASE IN CLOUDS NORTH
LATE WEDNESDAY AS A COLD FRONT DROPS SOUTH TO THE LOWER GREAT LAKES.
LOW LEVEL FLOW IS EXPECTED TO VEER TO THE NORTH TONIGHT...NORTHEAST
ON TUESDAY AND SOUTHWEST BY WEDNESDAY. THIS WILL ALLOW TEMPERATURES
TO WARM TO THE MID 30S NORTH AND LOWER 40S SOUTH PER SIMILAR 00Z MOS
AND ALLBLEND BY WEDNESDAY. THE DRY WEATHER WILL ALLOW MINOR TO
MODERATE RIVER FLOODING TO RUN ITS COURSE WITHOUT ANY HITCHES.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 331 AM EST MON JAN 14 2013
A COOL DRY WEATHER PATTERN WILL REMAIN IN PLACE FOR MOST OF THE
LONG TERM PERIOD. A DISTURBANCE WILL PASS ACROSS THE GREAT LAKES
REGION ON SATURDAY...BUT WILL NOT IMPACT CENTRAL INDIANA. THE MAIN
FOCUS OF THE EXTENDED PERIOD IS AT THE TAIL END WHEN A BROAD
UPPER LEVEL TROUGH WILL BRING THE NEXT CHANCE FOR SOME SNOW TO
CENTRAL INDIANA. THE EURO IS THE MOST AGGRESSIVE WITH THE
LOW...HINTING AT SOME ACCUMULATING SNOWFALL...AND THE LATEST
INITIALIZATION IS FAVORING THE EURO OVER THE GFS. WILL NOT DEVIATE
THIS FAR OUT. BEYOND THAT...MODELS ARE HINTING AT A VERY FRIGID
AIRMASS BY THE MIDDLE OF NEXT WEEK.
&&
.AVIATION /DISCUSSION FOR 141800Z TAF ISSUANCE/...
ISSUED AT 1222 PM EST MON JAN 14 2013
MVFR CEILINGS LIKELY TO PERSIST THROUGH THE AFTERNOON...AND
POSSIBLY TO SOME DEGREE TONIGHT.
THE COMBINATION OF COLD ADVECTION...GOOD LAPSE RATES AND VEERING
N/NE FLOW IN THE LOWER LEVELS HAS ENABLED CEILINGS AROUND 1500FT
TO REDEVELOP AND EXPAND BACK INTO CENTRAL INDIANA EARLY THIS
AFTERNOON. WITH MOISTURE INCREASING A BIT THROUGH THE BOUNDARY
LAYER...EXPECT MVFR CEILINGS TO MAINTAIN TO SOME DEGREE FOR THE
REST OF THE AFTERNOON. IN ADDITION TO THE STRATOCU...FAIRLY DENSE
CANOPY OF MID LEVEL CLOUDS WILL MOVE ACROSS THE OHIO VALLEY IN FAT
SOUTHWEST FLOW ALOFT. NORTHERLY WINDS WILL BE LESS THAN 10KTS
THROUGH SUNSET.
CLOUD FORECAST TONIGHT HAS SOME UNCERTAINTY AS RAP SOUNDINGS
INDICATING SHALLOW LAYER OF LOW LEVEL MOISTURE PERSISTING. WHILE
FLOW THROUGH 925MB WEAKENS...IT REMAINS FROM THE NORTHEAST INTO
THE OVERNIGHT. HAVE INTRODUCED SCATTERED CEILINGS AT 1500FT
TONIGHT AND WILL ADJUST AS NECESSARY. MID LEVEL CLOUDS WILL
CONTINUE TO MOVE ACROSS THE REGION IN THE SOUTHWEST FLOW AS WELL.
SHOULD FINALLY SEE MOSTLY CLEAR SKIES BY TUESDAY MORNING AS CENTER
OF HIGH PRESSURE BUILDS ACROSS THE OHIO VALLEY WITH DEEPER
SUBSIDENCE NOTED IN THE MODEL SOUNDINGS. WINDS WILL VEER TO THE
NORTHEAST AND REMAIN AT 10KTS OR LESS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...MK/CP
SHORT TERM...MK
LONG TERM....TDUD
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
233 PM MST MON JAN 14 2013
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 111 PM MST MON JAN 14 2013
CURRENT WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE TROUGH EXTENDING
FROM CANADA ACROSS THE PLAINS AND SW US TO THE BAJA PENINSULA. MEAN
AXIS IS CURRENTLY UPSTREAM OF CWA ALONG THE CENTRAL ROCKIES WITH
SURFACE TROUGH ALONG FRONT RANGE.
RUC INDICATES AXIS OF H85-H7 FRONTOGENESIS IN PLACE ACROSS EASTERN
COLORADO AND FAR WESTERN KANSAS WHERE LIGHT SNOW HAS BEEN FALLING
FOR MOST OF THE DAY. AS THE UPPER LEVEL TROUGH SHIFTS EAST THIS
EVENING THIS AXIS OF FORCING WILL BEGIN TO WEAKEN AND SHIFT
SOUTH...WITH SNOW COMING TO AN END OVER OUR SW CWA BY 03Z. I
COULD NOT RULE OUT ADDITIONAL SNOW ACCUMULATION AROUND ONE INCH
ALONG AN AXIS FROM STRATTON COLORADO TO BENKELMAN NEBRASKA THROUGH
THIS AFTERNOON WHERE RADAR SHOWS SOME INTENSIFICATION...HOWEVER
MOST LOCATIONS SHOULD SEE LESS THAN ONE HALF INCH TOTAL SNOW
ACCUMULATION FOR THIS EVENT. SUBSIDENCE AND A DRY AIR MASS WILL
BEGIN TO WORK IN OVER THE CWA AFTER MIDNIGHT WITH CLEARING SKIES
FROM THE NORTHWEST OVERNIGHT. THERE WILL BE LITTLE CHANGE IN THE
COLD AIRMASS FROM LAST NIGHT...SO DEPENDING ON HOW QUICKLY
CLOUDS CLEAR WE COULD SEE NEGATIVE TEMPERATURES ONCE AGAIN OVER
PARTS OF THE CWA. FOR NOW I LIMITED COLDEST TEMPS TO THE NORTH AND
WEST WHERE CLOUDS ARE MOST LIKELY TO CLEAR BEFORE SUNRISE.
AIRMASS WILL BEGIN TO MODERATE BY MIDDAY TUESDAY AS LEE TROUGH
DEVELOPS AND WINDS SHIFT TO THE WEST. IT IS A TOUGH CALL ON WHAT
IMPACT LINGERING SNOW PACK WILL HAVE...HOWEVER WE SHOULD SEE
TEMPERATURES IN THE LOW TO MID 30S ACROSS ALL THE CWA...WITH A FEW
LOCATIONS IN THE SOUTH AND EAST POSSIBLY WARMER.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 233 PM MST MON JAN 14 2013
FORECAST PROBLEMS WILL BE AMOUNT OF WARMUP DURING THE EARLY PORTION
OF THIS PERIOD FOLLOWED BY HOW MUCH TO COOL IT DOWN AT THE END OF
THE PERIOD. SATELLITE SHOWING AN AMPLIFIED FLOW STARTING WITH A
BROAD...DEEP AND COMPLICATED UPPER TROUGH OVER THE WESTERN HALF OF
THE PACIFIC WHICH IS MAINTAINING/AMPLIFYING AN UPPER RIDGE NEAR THE
WEST COAST OF NORTH AMERICA. THIS TRANSITIONS TO A TROUGH OVER THE
CENTER OF THE COUNTRY WHICH HAS/CONTINUES TO SPLIT. COLD AIR REMAINS
OVER THE AREA AND UPSTREAM AT THIS TIME.
MODELS INITIALIZED FINE AT JET LEVEL. HOWEVER...THEY WERE A LITTLE
UNDERDONE ON THE SPEEDS BEHIND THE UPPER TROUGH OVER THE COUNTRY.
THE GFS WAS DOING A LITTLE BETTER THAN THE CANADIAN AND NAM. MODELS
INITIALIZED FINE AT MID LEVELS WITH THE ECMWF AND UKMET DOING A
LITTLE BETTER THAN THE GFS AND CANADIAN. THE ECMWF WAS DOING THE
BEST AT THE SURFACE. THE ECMWF WAS DOING A LITTLE BETTER THAN THE
GFS...UKMET AND CANADIAN ON THE LOW LEVEL THERMAL FIELD.
TUESDAY NIGHT/WEDNESDAY...LEFT FRONT QUADRANT OF THE JET MOVES
ACROSS DURING THE NIGHT. UPPER TROUGH WILL HAVE MOVED EAST OF THE
AREA BY THE BEGINNING OF THIS PERIOD. IN ADDITION TO THE LIFT FROM
THE JET...MOISTURE INCREASES THROUGH MID LEVELS ON THE WEST SIDE OF
THE TROUGH. THERE IS SOME MODERATE FRONTOGENESIS AS WELL. LAPSE
RATES ARE NOT THAT GREAT. HOWEVER WITH THE COLD AIR IN PLACE AND THE
MODELS SHOWING DEEP ENOUGH MOISTURE...WILL INSERT FLURRIES INTO
THE NORTHWEST HALF SINCE THE SYNOPTIC LIFT IS NOT THAT GREAT BUT
MESOSCALE FORCING IS PRETTY GOOD. WHATEVER FALLS SHOULD BE DONE BY
06Z.
AFTER THE FLURRIES END...SUBSIDENCE INCREASE BEHIND JET AND UPPER
TROUGH. SO WINDS COULD BECOME BREEZY FROM A DOWNSLOPE DIRECTION FOR
A SHORT PERIOD OF TIME. THIS SHOULD MAKE THE MINS WARMER AND DID
WARM THEM SOME BUT MAYBE NOT ENOUGH. PLENTY OF SUN AND DOWNSLOPE
WINDS SHOULD MAKE FOR A MUCH WARMER DAY THAN WE HAVE BEEN HAVING
LATELY. IN GENERAL...MAXES SHOULD RANGE FROM THE MIDDLE 40S TO NEAR
50 DEGREES.
WEDNESDAY NIGHT/THURSDAY...DOWNSLOPE WINDS SHOULD KEEP MINS WARMER
AGAIN. WILL HAVE PLENTY OF SUN BUT NOT AS FAVORABLE OF A WIND FIELD.
NEW GUIDANCE INDICATES HIGH TEMPERATURES SIMILAR TO WEDNESDAYS AND
DID NOT CHANGE MUCH.
THURSDAY NIGHT THROUGH MONDAY...CURRENT AMPLIFIED PATTERN FLATTENS
OUT A LITTLE BIT EARLY IN THE PERIOD BEFORE BECOMING VERY AMPLIFIED
BY THE END OF THE PERIOD ONCE AGAIN. THROUGH FRIDAY SHOULD MAINTAIN
HIGH TEMPERATURES VERY SIMILAR TO WHAT THEY WERE ON WEDNESDAY AND
THURSDAY. THEN A BIG CHANGE IS GOING TO OCCUR IN TEMPERATURE BUT
WITH UNCERTAINTY IN TIMING AND MAGNITUDE OF THIS TEMPERATURE.
GIVEN WHAT THE PATTERN IS...HAVING A MUCH COLDER AIR MASS INTRUDE
INTO THE REGION IS PRETTY MUCH A GIVEN BUT THE MODELS DISAGREE ON
HOW FAST THEY WHAT TO DO IT. THE GFS AND CANADIAN BRING IN THE
COOLER AIR FASTER WHICH IS FROM LATE SATURDAY AFTERNOON INTO THE
NIGHT. THE 00Z AND 12Z ECMWF PRETTY MUCH KEEP THE COLDER AIR OUT
DURING THE DAY ON SATURDAY. HOWEVER...THE 12Z ECMWF IS MUCH QUICKER
THAN THE OLD RUN IN BRINGING THE COLDER AIR ON SATURDAY NIGHT AND
SUNDAY WHICH A BIG DIFFERENCE ON SUNDAY MAXES. MODELS IN BETTER
AGREEMENT AND MUCH BETTER THAN EARLIER IN BRINGING IN AN ABSOLUTELY
FRIGID AIR MASS SUNDAY NIGHT INTO MONDAY.
THROUGH SATURDAY NIGHT LEFT IN WHAT THE CRH_INIT GAVE ME ALTHOUGH IT
IS POSSIBLE THAT SATURDAY AND SATURDAY NIGHT TEMPERATURES COULD BE
COLDER. FELT PER THE AMPLIFIED PATTERN MAKING THE AREA SUSCEPTIBLE
TO HAVING MUCH COLDER AIR BROUGHT IN...SIGNIFICANT SNOW FIELD OVER
THE NORTH CENTRAL PORTION OF THE COUNTRY...AND MORE MODEL SUPPORT FOR
A SOONER ARRIVING COLD AIR MASS WHICH IS NOT UNCOMMON WITH THIS
MAGNITUDE OF COLD AIR...ADJUSTED THE TEMPERATURES...ESPECIALLY THE
MAXES FOR SUNDAY AND MONDAY...DOWN FROM THE INIT. CONSIDERING THE
AIR MASS WE HAVE HAD IN PLACE FOR THE LAST FEW DAYS AND WHAT THE
MODELS ARE SHOWING...THESE TEMPERATURES WILL PROBABLY NOT BE COLD
ENOUGH...BUT STARTED THE TREND DOWN.
IN REGARDS TO THE PRECIPITATION...LEFT WHAT THE CRH_INIT GAVE ME
WHICH HAS IT DRY DURING THE ENTIRE PERIOD. ALTHOUGH WOULD NOT BE
SURPRISED TO SEE SOME FLURRIES WHEN THE COLD AIR MASS BEGINS TO
ENTER THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1028 AM MST MON JAN 14 2013
MAIN AVIATION CONCERN WILL CONTINUE TO BE LIGHT SNOW DURING THE
DAY TODAY AT BOTH KGLD AND KMCK. VFR CONDITIONS SHOULD
PERSIST...THOUGH EITHER TERMINAL MAY BRIEFLY DROP TO MVFR/IFR
BEFORE SNOW TAPERS OF THIS AFTERNOON/EVENING. CONFIDENCE WAS TOO
LOW...AND DUE TO THE INFREQUENCY OF THESE CONDITIONS AT KGLD SO
FAR THIS MORNING I DECIDED AGAINST A TEMPO GROUP DURING THIS
UPDATE. ANY LINGERING SNOW SHOULD END AT KMCK AROUND 00Z...AND BY
03Z AT KGLD. WINDS WOULD REMAIN AT OR BELOW 10KT THROUGH THE
PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
112 PM MST MON JAN 14 2013
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 111 PM MST MON JAN 14 2013
CURRENT WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE TROUGH EXTENDING
FROM CANADA ACROSS THE PLAINS AND SW US TO THE BAJA PENINSULA. MEAN
AXIS IS CURRENTLY UPSTREAM OF CWA ALONG THE CENTRAL ROCKIES WITH
SURFACE TROUGH ALONG FRONT RANGE.
RUC INDICATES AXIS OF H85-H7 FRONTOGENESIS IN PLACE ACROSS EASTERN
COLORADO AND FAR WESTERN KANSAS WHERE LIGHT SNOW HAS BEEN FALLING
FOR MOST OF THE DAY. AS THE UPPER LEVEL TROUGH SHIFTS EAST THIS
EVENING THIS AXIS OF FORCING WILL BEGIN TO WEAKEN AND SHIFT
SOUTH...WITH SNOW COMING TO AN END OVER OUR SW CWA BY 03Z. I
COULDNT RULE OUT ADDITIONAL SNOW ACCUMULATION AROUND ONE INCH
ALONG AN AXIS FROM STRATTON COLORADO TO BENKELMAN NEBRASKA THROUGH
THIS AFTERNOON WHERE RADAR SHOWS SOME INTENSIFICATION...HOWEVER
MOST LOCATIONS SHOULD SEE LESS THAN ONE HALF INCH TOTAL SNOW
ACCUMULATION FOR THIS EVENT. SUBSIDENCE AND A DRY AIR MASS WILL
BEGIN TO WORK IN OVER THE CWA AFTER MIDNIGHT WITH CLEARING SKIES
FROM THE NORTHWEST OVERNIGHT. THERE WILL BE LITTLE CHANGE IN THE
COLD AIRMASS FROM LAST NIGHT...SO DEPENDING ON HOW QUICKLY
CLOUDS CLEAR WE COULD SEE NEGATIVE TEMPERATURES ONCE AGAIN OVER
PARTS OF THE CWA. FOR NOW I LIMITED COLDEST TEMPS TO THE NORTH AND
WEST WHERE CLOUDS ARE MOST LIKELY TO CLEAR BEFORE SUNRISE.
AIRMASS WILL BEGIN TO MODERATE BY MIDDAY TUESDAY AS LEE TROUGH
DEVELOPS AND WINDS SHIFT TO THE WEST. IT IS A TOUGH CALL ON WHAT
IMPACT LINGERING SNOW PACK WILL HAVE...HOWEVER WE SHOULD SEE
TEMPERATURES IN THE LOW TO MID 30S ACROSS ALL THE CWA...WITH A FEW
LOCATIONS IN THE SOUTH AND EAST POSSIBLY WARMER.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 109 AM MST MON JAN 14 2013
THE PERSISTENT UPPER RIDGE REMAINS OVER THE EASTERN PACIFIC AND
WEST COAST OF THE UNITED STATES THROUGH THE LONG TERM PORTION OF
THE FORECAST. AS A RESULT THE UPPER FLOW OVER THE CENTRAL HIGH
PLAINS REGION REMAINS GENERALLY OUT OF THE NORTHWEST WITH THE
STRONGER NORTHERN BRANCH OF THE UPPER FLOW REMAINING OVER THE
NORTHERN PLAINS THROUGH THE LATTER PORTION OF THE WORK WEEK. THIS
WILL KEEP THE CENTRAL HIGH PLAINS REGION GENERALLY DRY AND WARMER
THAN NORMAL FOR THIS TIME OF YEAR AS ANY OF THE MAJOR DISTURBANCES
MOVING THROUGH THE UPPER FLOW WILL TRACK WELL TO THE NORTH OF THE
FORECAST AREA.
THROUGH THE WEEKEND AND INTO THE BEGINNING OF NEXT WEEK...THE RIDGE
SHARPENS OVER THE WEST COAST AND THE UPPER PATTERN BECOMES MORE
AMPLIFIED WITH THE UPPER FLOW TURNING MORE NORTHERLY OVER THE
ROCKIES AND HIGH PLAINS. THIS WILL ALLOW COLDER AIR TO DIVE DEEPER
TO THE SOUTH THROUGH THE PLAINS STATES WITH TEMPERATURES ACROSS
THE FORECAST AREA RETURNING TO NEAR NORMAL ON SUNDAY AND BECOMING
SLIGHTLY COOLER THAN NORMAL BY MONDAY. THERE IS A LITTLE
PRECIPITATION HINTED AT BY THE GFS ON SUNDAY NIGHT AND MONDAY AS
THE COLDER AIRMASS MOVES IN...BUT HAVE KEPT THE FORECAST DRY FOR
NOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1028 AM MST MON JAN 14 2013
MAIN AVIATION CONCERN WILL CONTINUE TO BE LIGHT SNOW DURING THE
DAY TODAY AT BOTH KGLD AND KMCK. VFR CONDITIONS SHOULD
PERSIST...THOUGH EITHER TERMINAL MAY BRIEFLY DROP TO MVFR/IFR
BEFORE SNOW TAPERS OF THIS AFTERNOON/EVENING. CONFIDENCE WAS TOO
LOW...AND DUE TO THE INFREQUENCY OF THESE CONDITIONS AT KGLD SO
FAR THIS MORNING I DECIDED AGAINST A TEMPO GROUP DURING THIS
UPDATE. ANY LINGERING SNOW SHOULD END AT KMCK AROUND 00Z...AND BY
03Z AT KGLD. WINDS WOULD REMAIN AT OR BELOW 10KT THROUGH THE
PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...DR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1223 PM EST MON JAN 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM EST MON JAN 14 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
EXTENDING FROM HUDSON BAY THROUGH THE NRN PLAINS INTO THE SW CONUS.
THE SHORTWAVE TROUGH THAT BROUGHT -SN/FLURRIES TO UPPER MI AND
HELPED ENHANCED THE LES INTO THE WEST HAD LIFTED OFF TO THE
NORTHEAST TOWARD QUEBEC. IN ITS WAKE...SHRTWV RIDGING WITH QVECTOR
DIV AND SUBSIDENCE HAS HELPED LIMIT LES INTENSITY OVERNIGHT.
UPSTREAM...ONLY A WEAK SHRTWV WAS NOTED OVER NEBRASKA. AT THE
SFC...A RIDGE EXTENDED FROM SASK THROUGH THE NRN PLAINS INTO THE MID
MS VALLEY RESULTING IN W TO WNW FLOW THROUGH THE NRN GREAT LAKES.
THE LINGERING LAKE INDUCED TROUGH HAS KEPT THE FOCUS OF LES OVER THE
KEWEENAW AND FOR LOCATIONS EAST OF P53.
INSTABILITY FOR LES WILL REMAIN FAVORABLE WITH 850 MB TEMPS NEAR
-19C PRODUCING LAKE INDUCED CAPES IN THE 400-500 J/KG RANGE. THE DGZ
WILL ALSO REMAIN IN THE CONVECTIVE LAYER...LEADING TO HIGH
SNOW/WATER RATIOS IN THE 25/1 TO 30/1 RANGE. UPSTREAM LOW LEVEL
MOISTURE OVER NRN MN WILL HELP MAINTAIN LES ACROSS WRN LAKE
SUPERIOR.
MODELS WERE CONSISTENT IN SUGGESTING THAT LOW LEVEL WINDS WILL
SLOWLY BACK. AS A RESULT...THE LES INTO THE ERN CWA COULD PRODUCE AN
ADDITIONAL 1 TO 3 INCHES BEFORE THE BANDS GRADUALLY SHIFT TOWARD THE
SHORELINE AND MOVE OUT OF THE AREA THIS AFTERNOON. OVER THE WEST...
THE HIGHER RES MODELS SUGGEST THAT THE STRONGEST LES BAND(S) MAINLY
NEAR THE SHORELINE OF ONTONAGON COUNTY TOWARD TWIN LAKES THIS
MORNING WOULD GRADUALLY SHIFT THROUGH NRN HOUGHTON COUNTY TODAY AND
EVENTUALLY TO CMX-P59 TONIGHT. THERE IS LOWER CONFIDENCE WITH THE
SNOWFALL RATES AND AMOUNT OF TIME IT WILL LINGER OVER ANY GIVEN
AREA. THE POTENTIAL REMAINS FOR LOCAL AMOUNTS IN THE 4 TO 8 INCH
RANGE BOTH TODAY AND TONIGHT AS IT LIFTS THROUGH THESE AREAS.
SO...THE LES WARNING WILL CONTINUE AT LEAST UNTIL 12Z/TUE.
OVER THE REST OF THE CWA...EXPECT MAINLY JUST A FEW FLURRIES OVER
THE NORTH OUTSIDE OF THE MAIN LES AREA. EVEN WITH MORE SUNSHINE
TODAY OVER THE SOUTH...TEMPERATURES WILL REMAIN AT OR BELOW NORMAL
FROM 12 TO 17 WEST AND IN THE LOWER 20S EAST. THERE MAY ALSO BE
ENOUGH CLEARING TONIGHT INLAND WITH LIGHT WSW WINDS AS THE RIDGE
BUILDS TOWARD THE REGION TO ALLOW TEMPS TO DIP TO AROUND ZERO.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 535 AM EST MON JAN 14 2013
TUESDAY LOOKS TO BE ONE OF THE FEW BREAKS FROM SNOW FOR MUCH OF THE
LAND CWA...AS WINDS BACK TO THE WEST-SOUTHWEST AHEAD OF AN
APPROACHING SHORTWAVE AND ASSOCIATED COLD FRONT. THIS WILL PUSH
WHAT IS LEFT OF THE BANDS CURRENTLY OVER NORTHERN HOUGHTON AND
KEWEENAW COUNTIES ALONG THE WESTERN SHORELINE DURING THE MORNING
AND THEN OFFSHORE DURING THE AFTERNOON. THE BANDS WILL ALSO BE
DIMINISHING IN INTENSITY DUE TO INCREASING H850 TEMPS.
ELSEWHERE...LOOKS TO BE A FAIRLY NICE DAY WITH ONLY A FEW MID LEVEL
CLOUDS MOVING THROUGH.
HEADING INTO TUESDAY NIGHT...LOOKS LIKE IT COULD BE GUSTY ACROSS
MUCH OF UPPER MICHIGAN AHEAD OF THE COLD FRONT. GALES OVER LAKE
SUPERIOR STILL LOOK LIKELY...SO WILL CONTINUE GALE WATCH. OVER
LAND...INVERSION WILL KEEP MUCH OF THE STRONG 50-60KT LOW LEVEL JET
ALOFT. BUT LATE IN THE NIGHT...THINK IT WILL GET A LITTLE GUSTY AS
THE 10-14MB 6HR PRESSURE FALLS MOVE ACROSS THE CWA. STRONGEST WINDS
WILL LIKELY END UP IN THE SOUTHWEST WIND DOWNSLOPE AREAS NEAR LAKE
SUPERIOR...MAYBE APPROACHING 35-45MPH...WHILE THE REST OF THE AREA
WILL SEE A FEW HOUR PERIOD OF 25-35MPH GUSTS.
THERE IS MUCH BETTER AGREEMENT WITH THE SHORTWAVE AND ASSOCIATED
COLD FRONT THAT MOVES THROUGH LATE TUESDAY NIGHT INTO WEDNESDAY
MORNING. DUE TO THIS...HAVE DELAYED THE START OF THE SNOW INTO THE
OVERNIGHT HOURS. BEST H500 HEIGHT FALLS STAY OVER NORTHERN LAKE
SUPERIOR AND SOUTHERN ONTARIO...BUT DECENT H850-500 Q-VECTOR
CONVERGENCE MOVES OVER THE NORTHERN HALF OF THE CWA. WILL CONTINUE
TO HIGHLIGHT THE HIGHEST POPS OVER THE NORTH HALF OF THE CWA...WITH
CHANCES ELSEWHERE. WITH IT MOVING THROUGH FAIRLY QUICKLY...DON/T
THINK THERE WILL BE TOO MUCH SNOW ACCUMULATION...WITH THE HIGHEST
AMOUNTS OVER THE KEWEENAW AND LUCE COUNTY WHERE THERE COULD BE SOME
ENHANCEMENT OFF LAKE MICHIGAN. THE LEAST AMOUNTS WILL LIKELY BE
OVER THE CENTRAL CWA...WHERE DRY LOW LEVEL AIR WILL LEAD TO SOME
INITIAL EVAPORATION OF THE SNOW. THERE IS A SLIGHT DELAY IN THE
COLD AIR SURGING IN BEHIND THE FRONT...SO AFTER SNOW DIMINISHES ON
WEDNESDAY MORNING AND EARLY AFTERNOON...PROBABLY WONT BE MUCH GOING
ON LAKE EFFECT WISE UNTIL THE COLDER ARRIVES LATE WEDNESDAY
AFTERNOON AND WEDNESDAY NIGHT.
BEHIND THE FRONT...PERSISTENT LAKE EFFECT SNOW IS EXPECTED WEDNESDAY
NIGHT THROUGH THURSDAY NIGHT FOR WEST TO NORTHWEST FLOW FAVORED
LOCATIONS. THE AREA WILL BE BETWEEN THE SURFACE LOW ROTATING OVER
HUDSON BAY AND A HIGH PRESSURE IN THE PLAINS STATES. H850 TEMPS
FALLING TO AROUND -24C BEHIND THE FRONT SHOULD PRODUCE SIGNIFICANT
LAKE INSTABILITY DUE TO LAKE SUPERIOR WATER TEMPS AROUND 3C. SINCE
MODELS ARE SHOWING THE INVERSION AROUND 5KFT TO BE FAIRLY
WEAK...LAKE INDUCED EQL LEVELS RISE TO 9-10KFT AND CAPE VALUES
APPROACH 900 J/KG. THESE ARE FAIRLY IMPRESSIVE VALUES...BUT THE
CONCERN WITH SIGNIFICANT SNOWFALL COMES WITH THE BEST MOISTURE
FOCUSED IN THE 2-5KFT RANGE. WITH THE COLD AIR...THE CONVECTIVE
PORTION OF THE LAKE EFFECT SHOULD BE ABOVE THE DGZ AND LEAD TO
MORE COLUMN/PLATE SNOW TYPE...AT LEAST FOR WEDNESDAY NIGHT AND
THURSDAY. THIS WILL LEAD TO LOWER SNOW RATIOS THAN WHAT HAVE BEEN
SEEN OVER THE LAST DAY AND GENERALLY IN THE 15-20 TO 1 RANGE. THE
PERSISTENT NATURE OF THE SNOW DURING THIS PERIOD WILL LIKELY
PRODUCE DECENT LAKE EFFECT SNOW ACCUMULATIONS IN THE FAVORED
LOCATIONS AND WILL CONTINUE TO MENTION PERIODS OF MODERATE SNOW IN
THE HWO. SINCE THE MODELS HAVE BEEN CONSISTENT ON THIS PERIOD OF
LES...WILL MAKE THE JUMP UP TO DEFINITE POPS IN THE WNW TO NW
FAVORED AREAS. TIMING OF SHORTWAVES AND ASSOCIATED POCKETS OF DEEPER
MOISTURE ARE DIFFICULT TO LOCATE/TIME IN NORTHWEST FLOW...BUT THEY
COULD LEAD TO PERIODS OF HEAVY SNOW. THIS WOULD ESPECIALLY BE
TRUE ON THURSDAY AFTERNOON/NIGHT WHEN TEMPS WARM SLIGHTLY TO RAISE
THE DGZ FROM THE SURFACE.
00Z GFS/ECMWF HAVE GOOD CONSISTENCY WITH SHORTWAVE AND CLIPPER
SYSTEM AFFECTING THE AREA ON FRIDAY. CONFIDENCE IN TIMING/LOCATION
STILL IS LOW...BUT THE LATEST TRENDS SUGGEST A BETTER H850 WAA
FOCUS ACROSS THE CWA FOR FRIDAY. THIS WOULD LEAD TO BETTER SNOWFALL
CHANCES /1-2IN OF ACCUM OVER MUCH OF THE CWA/ THAN THE LOW END
CHANCES THAT ARE CURRENTLY IN PLACE. IF MODELS CONTINUE TO SHOW
THIS IDEA...WILL NEED TO BUMP UP POPS.
NORTHWEST FLOW ALOFT WILL CONTINUE INTO THE WEEKEND AS A
UPPER RIDGE BUILDS OVER THE PACIFIC NORTHWEST. BUT MODELS ARE REALLY
STARTING TO DIFFER IN THE UPPER LOW SPINNING EAST OF HUDSON BAY AND
WHAT HAPPENS TO IT THROUGH THE WEEKEND. NO MATTER THE SOLUTION...IT
APPEARS THE AREA WILL STILL BE UNDER THE INFLUENCE OF THE UPPER
TROUGH BUT THERE APPEARS TO BE STRONGER SHORTWAVES DISRUPTING THE
TROUGH SOME. THESE DISRUPTIONS PRODUCES MORE UNCERTAINTY IN THE LOW
TRACK FORECAST...WHICH MAKES THE LOW LEVEL WIND FIELDS HIGHLY
VARIABLE FOR PINNING DOWN LAKE EFFECT AREAS IN ADDITION TO
SYNOPTIC SNOW. WILL FOLLOW A GENERAL MODEL CONSENSUS...WHICH
WILL CONTINUE TO FOCUS THE HIGHEST CHANCE POPS NEAR LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1223 PM EST MON JAN 14 2013
CMX...EXPECT PREDOMINANT MVFR CONDITIONS THRU THIS EVENING IN THE
LAKE EFFECT SNOW SHOWERS AND OBS WILL CONTINUE TO BE HIGHLY VARIABLE
AS BANDS MOVE THROUGH. AS THE FLOW BACKS MORE TO THE WSW...THE
HEAVIER SHSN SHOULD SHIFT TO THE N OF THE SITE LATE TONIGHT.
IWD/SAW...SLOWLY BACKING LLVL FLOW TO THE WSW WL ADVECT DRIER AIR
OVHD AND ALLOW FOR VFR WX THROUGH THE PERIOD. WILL BE A TEMPORARY
MVFR DECK AT IWD WITH LOW LEVEL MOISTURE THIS AFTERNOON MOVING
THROUGH.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EST MON JAN 14 2013
NORTHWEST WINDS WILL GRADUALLY BACK TODAY AND TONIGHT...WITH MOST
LOCATIONS SEEING WINDS IN THE 15-25KT RANGE. AS A COLD FRONT
APPROACHES THE AREA ON TUESDAY AND TUESDAY EVENING...SOUTHWEST
WINDS WILL INCREASE TO GALES OF 35-45KTS FOR TUESDAY NIGHT. THEN AS
THE FRONT MOVES THROUGH ON WEDNESDAY MORNING...THE WINDS ARE
EXPECTED TO VEER TO THE NORTHWEST AND STILL PRODUCE GALES TO 40KTS.
THE TIMING OF THE GALE WATCH LOOKS TO BE IN GOOD SHAPE AND WILL
KEEP IT IN PLACE.
NORTHWEST FLOW WILL REMAIN WEDNESDAY NIGHT INTO THURSDAY
NIGHT...WITH WINDS GENERALLY IN THE 15-30KT RANGE WITH A FEW GUSTS
TO 35KTS ON THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ001-003.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ006-007.
LAKE SUPERIOR...
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING FOR
LSZ265>267.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY AFTERNOON
FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
426 PM CST MON JAN 14 2013
.UPDATE...
.DISCUSSION...
QUICK UPDATE FOR SOUTHWEST NEBRASKA. THE RUC13 SHOWS AND AREA OF
LIGHT SNOW ON THE 285K INSENTROPIC SFC MOVING EAST THIS EVENING.
THE NEW FORECAST SLOWS THIS DOWN ABOUT 3 HOURS AND RAISES THE POP
TO 50 PERCENT. LESS THAN AN INCH ACCUMULATION IS EXPECTED
ALTHOUGH THE RUC SHOWS 3 INCHES. THE RUC IS OFTEN TOO WET. REST OF
THE FORECAST IS GOOD.
&&
.PREV DISCUSSION... /ISSUED 245 PM CST MON JAN 14 2013/
SYNOPSIS...
IN THE UPPER LEVELS...THE LARGE SCALE CYCLONIC FLOW CONTINUES
OVER A LARGE PART OF THE CENTRAL AND WESTERN U.S. RUNNING A 24 HOUR
LOOP OF THE IMAGERY...ONE CAN SEE THE DIGGING AND NARROWING OF THE
TROUGH. ANALYSIS OF THE 20Z SURFACE DATA REVEALED A WARM FRONT
DEVELOPING ACROSS EASTERN MONTANA AND EASTERN WYOMING.
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT.
A LOOK AT THE 280-290K LAYER INDICATES SOME WEAK ISENTROPIC LIFT
CONTINUING INTO THIS EVENING IN EXTREME SOUTHWEST NEBRASKA.
HOWEVER...VERY LITTLE MOISTURE AND ACCUMULATIONS WILL BE HALF AN
INCH OR LESS.
FOR TUESDAY...A WARM FRONT IS EXPECTED INTO WESTERN NEBRASKA BY
EARLY EVENING. AGAIN...IN THE 280-290K LAYER...ISENTROPIC UPGLIDE IS
LIKELY TO PRODUCE SOME CLOUDINESS AND POSSIBLY SOME LIGHT SNOW IN
THE EVENING AND LIGHT FREEZING DRIZZLE LATE TUESDAY NIGHT AND VERY
EARLY WEDNESDAY.
MEDIUM RANGE/EXTENDED...WEDNESDAY THROUGH SUNDAY.
DRY AND MUCH WARMER WEATHER CAN BE EXPECTED WEDNESDAY THROUGH
FRIDAY IN THE AFTERMATH OF THE WARM FRONT.
MUCH COLDER WEATHER IS EXPECTED AGAIN AS A BACK-DOOR FRONT COMES
ACROSS SATURDAY NIGHT AND SUNDAY. THE FRONT STALLS ALONG THE EASTERN
SLOPE OF THE ROCKIES AND SOUTHWEST FLOW WILL PRODUCE ISENTROPIC LIFT
AND COULD GIVE SOME POTENTIAL FOR WIDESPREAD SNOW MONDAY AS THE
SYSTEM MAKES ITS WAY BACK TO THE EAST-NORTHEAST. AT THAT RANGE...
THE UNCERTAINTY IS VERY HIGH REGARDING AMOUNTS AND INTENSITY OF
PRECIPITATION.
AVIATION...
FOR THE 18Z TAF FORECAST CYCLE...GENERAL VFR EXPECTED TODAY
ACROSS MOST AREA TERMINALS. THE EXCEPTION BEING ACROSS FAR
SOUTHWEST NEBRASKA TODAY...POSSIBLY AFFECTING THE KOGA AND KIML
TERMINALS WHERE SCATTERED LIGHT SNOW MAY BRIEFLY REDUCE VISIBILITIES
INTO MVFR. MODEL GUIDANCE HAS THE REMAINING LIGHT SNOW DISSIPATING
LATER THIS AFTERNOON...IF NOT ALREADY SO...THEREAFTER DRIER AIR
ALOFT WILL WORK BACK ACROSS THE REGION...WITH NO VISIBILITY OR
CEILING RESTRICTIONS ANTICIPATED. FOR THE OVERNIGHT...NAM SHORT
TERM GUIDANCE HINTS AT REDUCED VISIBILITY /DOWN TO 3SM/ AT KLBF
AFTER 06Z WITH THE FORMATION OF LOW FOG. FEEL THAT THE SOLUTION IS
OVERLY AMBITIOUS WITH THE REMAINING LOW LEVEL MOISTURE...SO WILL NOT
INCLUDE A MENTION OF MVFR VISIBILITY IN THE OFFICIAL TAF FORECAST
NOW. OTHERWISE BROAD SURFACE HIGH PRESSURE WILL KEEP WIND SPEEDS
RELATIVELY LIGHT AND VARIABLE FOR ALL TERMINALS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1233 PM EST MON JAN 14 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PRODUCE UNSEASONABLY WARM CONDITIONS
INTO MID-WEEK. A COLD FRONT WILL MOVE SLOWLY THROUGH THE AREA
LATE WEDNESDAY. WEAK GULF COAST LOW PRESSURE MAY BRING A CHANCE OF
LIGHT RAIN TO THE REGION THURSDAY NIGHT OR FRIDAY. HIGH PRESSURE
WILL BUILD IN BEHIND THE COLD FRONT FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM MONDAY...HAVE ADJUSTED TEMPS UP A COUPLE OF DEGREES
FOR TODAY KEEPING MAX TEMPS IN THE MID TO UPPER 70S. THE
SOUTHWESTERLY WINDS WILL BACK A BIT PRODUCING MORE OF AN ON
SHORE FLOW THROUGH THE AFTERNOON. THIS WILL KEEP TEMPS COOLER
ALONG THE SHORE...MOVING INLAND AS WINDS PICK UP THROUGH THE
AFTERNOON. SEA FOG WILL ALSO HELP TO KEEP TEMPS COOLER ALONG THE
COAST.
PREVIOUS DISCUSSION...MODELS INDICATE THE MID TO UPPER LEVEL RIDGE TO
REMAIN ANCHORED JUST OFF THE SE U.S. COAST DURING THIS NEAR TERM
PERIOD. THIS WILL SLOW DOWN THE PROGRESSION OF THE BAROCLINIC ZONE
IE. THE SFC COLD FRONT...TOWARD THE SOUTHEAST. IN FACT... MODELS
ACTUALLY STALL THE COLD FRONT JUST NORTH AND WEST OF THE FA AS IT
BECOMES ORIENTED PARALLEL WITH THE FLOW ALOFT. THE DEEPEST
MOISTURE WILL REMAIN JUST OUTSIDE OF THE ILM CWA DURING THIS NEAR
TERM PERIOD...REMAINING WEST THROUGH NORTH OF THE FA. AMAZINGLY...
GFS/NAM/EUROPEAN/ETC. AGREE THAT THIS SCENARIO WILL PLAY OUT. NOW
WHAT THEY DO NOT AGREE IS THE THREAT OR PROBABILITY FOR PCPN. WITH
THE BEST LIFT REMAINING OUTSIDE OF THE ILM CWA DOMAIN...HAVE
INDICATED A LOW CHANCE OF POPS FOR THE NW PORTIONS OF THE FA FROM
THIS AFTERNOON THROUGH TONIGHT...ROUGHLY ALONG AND WEST OF THE
I-95 CORRIDOR. THE LATEST RUN OF THE HRRR MODEL ALSO INDICATES
THIS PCPN POSSIBILITY. HAVE STAYED AWAY FROM MENTIONING THUNDER
DUE TO THE LACK OF INSTABILITY ILLUSTRATED BY LATEST NAMBUFR
SOUNDINGS...IE. NO CAPE...LI`S STAY MAINLY POSITIVE. WILL LIKELY
HAVE A SOMEWHAT OF A SHARP CLOUD GRADIENT ACROSS THE FA WITH THE
IMMEDIATE COAST HAVING THE BEST POTENTIAL TO OBSERVE THE DAYS
INSOLATION. THEREFORE...HAVE RELIED ON THE WARMER MODEL MOS
GUIDANCE FOR BOTH TODAYS MAX AND TONIGHTS MIN TEMPS. THIS WILL
RESULT IN ADDITIONAL MAX TEMP RECORDS LIKELY BEING SET FOR 1 MORE
DAY. AND FINALLY...THE MID TO UPPER LEVEL CLOUD DECK ACROSS THE FA
HAS BEEN OPAQUE ENOUGH TO PREVENT WIDESPREAD RADIATIONAL TYPE
DENSE FOG. HOWEVER...SEA FOG IE. ADVECTION TYPE FOG...WILL
SPORADICALLY AFFECT THE IMMEDIATE COAST AS SFC WINDS SLIGHTLY BACK
TO THE SSW AND PUSH 60+ DEWPOINTS ACROSS SSTS IN THE 50S RESULTING
WITH SEA FOG BRIEFLY PUSHING ONSHORE AT TIMES.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 245 AM MONDAY...WEAK FRONT WILL BE STALLED IN OR JUST WEST
OF THE REGION FOR A MAJORITY OF THE PERIOD. PROXIMITY TO FRONT
WILL CREATE SIGNIFICANT TEMP GRADIENT ACROSS THE
REGION...PROVIDING PLENTY OF POTENTIAL FOR THE FORECAST TO GO
WRONG. SOME WEAK ISENTROPIC LIFT AND LOW LEVEL MOISTURE MAY
PRODUCE SOME PATCHY LIGHT RAIN AT TIMES. ALTHOUGH DRY MID AND
UPPER LEVELS WILL LIKELY KEEP MUCH OF THE AREA DRY FOR A MAJORITY
OF THE PERIOD. COMBINATION OF FRONT IN THE REGION AND LOW LEVEL
CLOUD COVER WILL TEMPER HIGHS ACROSS PORTIONS OF THE FORECAST AREA
BOTH DAYS. COASTAL SC ENDS UP WARMEST WITH A LITTLE LESS CLOUD
COVER AND SOUTHERLY FLOW INTO WED NIGHT. HIGHS WILL BE IN THE LOW
70S WITH LOWS IN THE UPPER 50S TO AROUND 60.
INLAND SC AND NC WILL HAVE BEST PRECIP CHANCES...THOUGH AT THIS
POINT LITTLE MORE THAN LOW CHANCE OR SLIGHT CHANCE APPEARS
WARRANTED. HIGH TEMP FORECAST WILL BE TRICKY IN THESE AREAS WITH
LOCATION OF FRONT...AND THE NORTHERLY FLOW BEHIND IT...LEADING TO A
SHARP GRADIENT SOMEWHERE IN THE FORECAST AREA. FOR NOW WILL GO WITH
HIGHS NEAR TO ABOVE CLIMO TUE AND ABOVE TO WELL ABOVE CLIMO WED.
HOWEVER A MORE EASTERLY POSITION OF THE FRONT WED...SOMETHING
GUIDANCE IS TRENDING AWAY FROM...WOULD RESULT IN COOLER TEMPS. LOWS
WILL CONTINUE TO RUN ABOVE CLIMO REGARDLESS OF FRONTAL POSITION
GIVEN PLENTY OF CLOUD COVER AND LIMITED COLD ADVECTION ON BACKSIDE
OF THE BOUNDARY.
FRONT IS PULLED OFF THE COAST WED NIGHT BY WEAK SURFACE LOW MOVING
INTO THE CANADIAN MARITIMES. LACK OF ANY MID LEVEL PUSH TRANSLATES
TO MINIMAL TEMP REDUCTION AS THE PERIOD ENDS. NORTH TO NORTHEAST
FLOW ACROSS THE AREA BY END OF PERIOD ONLY DROPS WED NIGHT LOWS A
FEW DEGREES.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 245 AM MONDAY...SOUTHERN STREAM SYSTEM EMERGING FROM THE
SOUTHWEST MID WEEK WILL BRING THE PERIODS BEST AND ONLY PRECIP
CHANCE THU NIGHT INTO FRI. DEEP SOUTHWEST FLOW AHEAD OF THE WAVE
AS IT CROSSES THE GULF COAST INCREASES MOISTURE OVER THE
SOUTHEAST THU. DIVERGENT PATTERN ALOFT THU NIGHT INTO FRI IS
ENHANCED BY 200MB JET STREAK APPROACHING 120 KT. RIGHT NOW THE
BIGGEST NEGATIVE FACTOR APPEARS TO BE THE TRACK OF THE MID LEVEL
FEATURE AND THE ASSOCIATED SURFACE WAVE. WEAK SURFACE LOW DEVELOPS
ALONG FRONT STALLED ACROSS NORTHERN GOMEX EARLY THU. THIS LOW
TRACKS NORTHEAST ALONG THE FRONT...PASSING OFF THE SOUTHEAST COAST.
THIS KEEPS NORTHEAST LOW LEVEL FLOW IN PLACE FOR THE DURATION OF
THE EVENT. BELOW 700MB OR SO FORECAST SOUNDINGS DEPICT A SATURATED
BUT VERY STABLE AIR MASS. SO WHILE MID AND UPPER LEVEL FORCING
WILL BE PRESENT IT APPEARS THE LOW LEVEL STABILITY WILL ULTIMATELY
WIN OUT. THUS HAVE GONE FOR LOWER POP AND MINIMAL QPF EARLY IN THE
PERIOD.
AS SURFACE AND MID LEVEL FEATURES MOVE OFF TO THE NORTHEAST HIGH
PRESSURE BUILDS IN UNDER DEVELOPING PROGRESSIVE MID LEVEL PATTERN.
THIS ALLOWS MUCH DRIER AND COOLER AIR TO SPREAD IN FROM THE WEST.
PINCHED GRADIENT ALONG THE COAST WILL KEEP NORTHEAST FLOW BRISK INTO
SAT MORNING...ESPECIALLY ALONG THE COAST. LATE IN THE PERIOD MEDIUM
RANGE GUIDANCE IS TRYING TO SHOW A WEAK COASTAL LOW DEVELOPING ON
REMAINS OF STALLED SURFACE BOUNDARY. GIVEN THE TIME RANGE AND
POTENTIAL FOR SIGNIFICANT CHANGES REGARDING THIS FEATURE WILL NOT
INTRODUCE A POP LATE IN THE PERIOD. TEMPS NEAR CLIMO THROUGH THE
PERIOD.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...STAGNANT SYNOPTIC PATTERN WILL KEEP THE FRONT WEST OF
THE REGION...WITH MAINLY THICK HIGH CLOUDS IN AND OUT OF OUR WESTERN
TERMINALS. SOUTHWEST FLOW THIS AFTERNOON WILL SHIFT 20-30 DEGREES TO
THE SOUTH WITH THE RESULTANT AROUND BEGINNING OF TAF TIME.
TONIGHT...FRONT REMAINS WEST OF THE REGION...IT MAY IN FACT
RETROGRADE FARTHER WEST. SCATTERED CIRRUS OVERNIGHT WITH A GOOD
CHANCE OF FOG/STRATUS AFTER 08Z. TUESDAY...BECOMING VFR BY 14-15Z
WITH CONTINUED SOUTHWEST FLOW.
EXTENDED OUTLOOK...MORNING FOG/STRATUS EXPECTED AT ALL TERMINALS
WEDNESDAY. SLIGHT CHANCE OF SHOWERS WEDNESDAY AFTERNOON. A BETTER
CHANCE OF SHOWERS FRIDAY INTO SATURDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM MONDAY...SFC PRESSURE PATTERN INDICATES THE WESTERN
ATLANTIC HIGH...CENTERED OFFSHORE FROM THE SE U.S. COAST...WILL
PRODUCE SSW THROUGH WSW WIND DIRECTIONS. THE SFC PG WILL SLIGHTLY
TIGHTEN AS THE SFC COLD FRONT APPROACHES FROM THE NW TODAY...
BEFORE STALLING BETWEEN DUCK NC SOUTHWEST TO PENSACOLA BEACH
FLORIDA TONIGHT. LOOK FOR WIND SPEEDS AT 5 TO 10 KT THIS
MORNING...INCREASING TO 10 TO POSSIBLY 15 KT THIS AFTERNOON AND
TONIGHT. SIGNIFICANT SEAS WILL RUN 2 TO 3 FT...EXCEPT UP TO 4 FT
ACROSS THE OUTER WATERS OFF CAPE FEAR THIS AFTERNOON AND/OR
TONIGHT. GENERALLY...A 1 1/2 TO 2 1/2 FOOT ESE GROUND SWELL
EXHIBITING 9 TO 12 SECOND PERIODS WILL DOMINATE SIG. SEAS. THE
ADDITION OF 3 TO 5 SECOND PERIOD WIND DRIVEN WAVES WILL PUSH SIG.
SEAS TO THE 4 FOOT LEVEL OFF CAPE FEAR LATER TODAY AND TONIGHT.
SEA FOG WILL ALSO REMAIN A THREAT TO MARINERS THIS FORECAST
PERIOD...OCCASIONALLY AND BRIEFLY MOVING ONSHORE. VSBY ROUGHLY 1
NM OR LESS WITHIN THE SEA FOG.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 245 AM MONDAY...SOUTHWEST FLOW REMAINS IN PLACE FOR A
MAJORITY OF THE PERIOD WITH SPEEDS GENERALLY 10 TO 15 KT. WEAK
SLOW MOVING FRONT DROPPING IN FROM THE NORTH-NORTHWEST LATE IN THE
PERIOD WILL BRING ABOUT A WIND SHIFT TO NORTHERLY BY THE END OF
THE PERIOD BUT LACK OF COLD ADVECTION OR SIGNIFICANT GRADIENT WILL
KEEP SPEEDS LIGHT...10 KT OR LESS. SEAS WILL RUN 2 TO 4 FT THROUGH
THE PERIOD...MAINLY AS SOUTHERLY WIND WAVE.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 245 AM MONDAY...NORTH TO NORTHEAST FLOW THU STARTS TO
INCREASE THU NIGHT...BUT QUESTION REMAINS BY HOW MUCH. WEAK LOW
PRESSURE EMERGING FROM NORTHEAST GOMEX WILL PINCH GRADIENT...BUT
HOW TIGHT GRADIENT BETWEEN THIS LOW AND THE HIGH BUILDING IN FROM
THE NORTHWEST BECOMES IS UNCERTAIN. ALL OF THE MEDIUM RANGE
GUIDANCE DEPICTS THIS SURFACE WAVE PASSING EAST OF THE WATERS
LATE THU NIGHT OR EARLY FRI...SO FEEL THAT AN INCREASE IN
NORTHEAST FLOW IS LIKELY FOR SECOND HALF OF THE PERIOD. AT THIS
POINT CANNOT SAY IF HEADLINES WILL BE NEEDED BUT IT CERTAINLY
APPEARS TO BE A POSSIBILITY. CURRENT SEAS FORECAST IS 2 TO 4 FT
THU BUILDING TO 3 TO 5 ON FRI. HOWEVER IT IS WORTH NOTING THAT WW3
GUIDANCE IS COMING IN CLOSE TO 10 FT FRI.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ
SHORT TERM...III
LONG TERM...III
AVIATION...DL
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1130 AM CST MON JAN 14 2013
.DISCUSSION.../ISSUED AT 1130 AM CST/
UPDATED THE AFTERNOON GRIDS TO INCLUDE A FEW FLURRIES FOR OUR FAR
NORTHERN ZONES ALONG HIGHWAY 14. MID LEVEL CLOUDINESS WILL BE
PREVALENT IN THOSE AREAS ASSOCIATED WITH A SLOW MOVING SHORT WAVE.
BUT CURRENT THINKING IS THAT LOWER CLOUDS WILL STAY TO THE NORTH OF
OUR FORECAST AREA WHICH WOULD AID IN PRODUCING POCKETS OF LIGHT
SNOWFALL WHICH COULD MEASURE A LITTLE BIT. /MJF
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
VFR WILL BE THE PRIMARY CATEGORY THIS AFTERNOON...TONIGHT AND
TUESDAY MORNING. MID LEVEL CLOUDS WILL STREAM ACROSS OUR FAR
NORTHERN ZONES THIS AFTERNOON...AND EVEN SOMEWHAT TONIGHT...
ASSOCIATED WITH A MID LEVEL SHORT WAVE WHICH IS MOVING VERY SLOWLY
ACROSS THIS AREA. IN ADDITION...SOME LOWER VFR CEILINGS ARE LIKELY
TO MOVE NORTHWARD INTO THE SIOUX CITY AND STORM LAKE IOWA AREAS
OVERNIGHT AND LATE TONIGHT. THOSE POTENTIAL CLOUDS ARE CURRENTLY
EVIDENT IN SOUTHWEST NEB AND NORTHEAST CO. OTHERWISE...WITH A VERY
LIGHT SOUTH WIND...SOMETIMES SOME MVFR HAZE OCCURS IN THE MORNING
HOURS. SO FOR NOW PUT THAT POSSIBILITY IN A TEMPO GROUP FOR OUR
THREE TAF SITES. /MJF
&&
.PREVIOUS DISCUSSION.../ISSUED AT 415 AM CST/
FAIRLY QUIET WEEK AHEAD...WITH MAIN ENERGY FROM A COUPLE OF WAVES
EXPECTED TO REMAIN NORTH OF THE AREA...LEAVING TEMPERATURES AS
PRIMARY CONCERN THROUGH NEXT WEEKEND.
FOR TODAY...WEAK WAVE SLIDING NORTHEAST ACROSS OUR AREA AHEAD OF
MID-UPPER TROUGH DROPPING SOUTHEAST INTO THE UPPER MIDWEST. WITH
COLD AIR MASS STILL IN PLACE AND WEAK LIFT FROM THIS WAVE...STILL
SEEING FLURRIES BEING SQUEEZED OUT OF ANY LOWER/DEEPER MOISTURE
LAYERS. RAP SEEMS TO BE HANDLING THE MOISTURE FAIRLY WELL...AND
KEEPS DEEPER MOISTURE ACROSS CENTRAL/NORTHERN CWA THIS MORNING...
SHIFTING EAST OF THE AREA THROUGH THE AFTERNOON. DEEPER MOISTURE
AGAIN LIES IN FAVORABLE TEMPERATURE ZONE FOR ICE PRODUCTION /A FEW
DEGREES EITHER SIDE OF -15C/...THUS HAVE ADDED SCATTERED FLURRIES
ALONG/NORTH OF I-90 THROUGH MIDDAY.
TEMPERATURES SHOULD REBOUND A BIT FROM WEEKEND CHILL AS WARMER LOW
LEVEL AIR BEGINS TO WORK INTO THE AREA THIS AFTERNOON. STILL ONE
MORE DAY BELOW NORMAL THOUGH... WITH HIGHS IN THE TEENS TO LOWER
20S. ONE THING OF NOTE ON TEMPS THROUGHOUT MUCH OF THE FORECAST...
NAM/GFS APPEAR TO HAVE POORLY INITIALIZED SNOW COVER IN THE MODEL...
WHICH SEEMS TO BE HAVING A LARGE EFFECT ON THEIR RESPECTIVE SURFACE
TEMPERATURE FORECASTS... SEEN BOTH IN THE RAW MODELS/MOS OUTPUT...
THOUGH SOMEWHAT LESSER EXTENT IN THE LATTER. THUS HAVE CHOSEN TO
FAVOR WARMER GEM/ECMWF TEMPERATURES THROUGH MOST OF THE WEEK...
ESPECIALLY THROUGH FRIDAY WHEN WARM AIR ALOFT REMAINS IN PLACE.
NEXT WAVE MOVES ACROSS THE REGION TUESDAY/TUESDAY NIGHT. STRONG WARM
ADVECTION WILL LEAD TO POTENTIAL FOR A LITTLE LIGHT SNOW OR FLURRIES
AHEAD OF THE WARM AIR...WHICH WILL SPREAD ACROSS THE FORECAST AREA
IN EARNEST TUESDAY NIGHT. LITTLE ACCUMULATION EXPECTED...WITH MAYBE
A QUARTER INCH OR SO ALONG THE HIGHWAY 14 CORRIDOR. STOUT SOUTHWEST
FLOW AHEAD OF THE WARM FRONT WILL RESULT IN GUSTY WINDS ATOP AND
DOWNSTREAM OF THE BUFFALO RIDGE MUCH OF THE NIGHT. EXPECT EARLY
EVENING LOWS FROM AROUND 20 IN THE EAST TO THE MID-UPPER 20S WEST OF
THE JAMES VALLEY...WITH MOST AREAS WARMING TO NEAR FREEZING OR JUST
SHY BY DAYBREAK WEDNESDAY AS WINDS TURN TO THE WEST BEHIND THE WARM
FRONT. STILL LOOKS LIKE A MILD DAY WITH TEMPS ONLY WARMING A FEW
MORE DEGREES THROUGH THE DAY TO HIGHS OF 35 TO 45.
BACKDOOR COOL FRONT DROPS THROUGH NORTHEAST PORTIONS OF THE FORECAST
AREA WEDNESDAY NIGHT/THURSDAY. TEMPERATURES STILL EXPECTED TO BE
ABOVE NORMAL THURSDAY THOUGH...WITH HIGHS UPPER 20S NORTHEAST TO THE
MID 30S THROUGH THE MISSOURI VALLEY. GEM/ECMWF BOTH SHOWING ANOTHER
WARM PUSH FRIDAY AHEAD OF STRONGER PUSH OF COLD AIR EXPECTED NEXT
WEEKEND. HAVE NUDGED TEMPERATURES A FEW DEGREES ABOVE GENERAL MODEL
CONSENSUS...THOUGH COULD BE EVEN WARMER IF 14/00Z ECMWF PANS OUT.
A COUPLE OF QUICK MOVING WAVES DIVE SOUTHEAST ACROSS NORTH DAKOTA
AND NORTHERN MINNESOTA DURING THE LONGER RANGE. THE FIRST WEAKER
WAVE MOVES THROUGH THURSDAY NIGHT...LEAVING A TIGHTENING THERMAL
GRADIENT WHICH NEXT STRONGER WAVE CAN WORK WITH SATURDAY. THIS WAVE
WILL PUSH THE ARCTIC FRONT SOUTH THROUGH THE REGION...BRINGING A
RETURN TO BELOW NORMAL TEMPERATURES BY THE LATTER HALF OF NEXT
WEEKEND. AS WAS MENTIONED ABOVE...ENERGY APPEARS TO REMAIN WELL
NORTH OF OUR AREA AT THIS TIME...SO WILL KEEP THE LONGER RANGE DRY
FOR NOW. HOWEVER WILL HAVE TO WATCH FOR POTENTIAL OF SOME LIGHT SNOW
SUNDAY AS YET ANOTHER WAVE DROPS INTO THE ARCTIC AIR MASS WHICH IS
EXPECTED TO PUSH BACK INTO THE REGION BY THEN.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1039 AM CST MON JAN 14 2013
.DISCUSSION.../ISSUED AT 1040 AM CST/
MAINLY TWEAKED THE FORECAST TO REDUCE CLOUD COVER OVER MUCH OF THE
FORECAST AREA...MINUS OUR NORTHERN ZONES WHERE MID LEVEL CLOUDINESS
SHOULD ADVECT EASTWARD THROUGH THE COURSE OF THE DAY. BUT OTHERWISE
THIS AFTERNOON HIGHS SHOULD BE CLOSE. /MJF
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
AN AREA OF CEILINGS 1-3K FEET SHOULD BE EXITING SOUTHWEST MN BY 15Z.
OTHERWISE VFR IS EXPECTED OVER THE AREA THROUGH 15/12Z. AREAS OF
CEILINGS 3-5K FEET WILL PASS OVER THE AREA NORTH OF INTERSTATE 90
THROUGH 15/06Z WITH CEILINGS ELSEWHERE UNRESTRICTED OR ABOVE 5K
FEET. IT APPEARS AIR WILL BE TOO DRY FOR PATCHY FOG IN LIGHT WIND
REGIME NEAR END OF PERIOD AT 15/12Z. SURFACE WINDS SHOULD BE 10
KNOTS OR LESS THROUGH 15/12Z.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 415 AM CST/
FAIRLY QUIET WEEK AHEAD...WITH MAIN ENERGY FROM A COUPLE OF WAVES
EXPECTED TO REMAIN NORTH OF THE AREA...LEAVING TEMPERATURES AS
PRIMARY CONCERN THROUGH NEXT WEEKEND.
FOR TODAY...WEAK WAVE SLIDING NORTHEAST ACROSS OUR AREA AHEAD OF
MID-UPPER TROUGH DROPPING SOUTHEAST INTO THE UPPER MIDWEST. WITH
COLD AIR MASS STILL IN PLACE AND WEAK LIFT FROM THIS WAVE...STILL
SEEING FLURRIES BEING SQUEEZED OUT OF ANY LOWER/DEEPER MOISTURE
LAYERS. RAP SEEMS TO BE HANDLING THE MOISTURE FAIRLY WELL...AND
KEEPS DEEPER MOISTURE ACROSS CENTRAL/NORTHERN CWA THIS MORNING...
SHIFTING EAST OF THE AREA THROUGH THE AFTERNOON. DEEPER MOISTURE
AGAIN LIES IN FAVORABLE TEMPERATURE ZONE FOR ICE PRODUCTION /A FEW
DEGREES EITHER SIDE OF -15C/...THUS HAVE ADDED SCATTERED FLURRIES
ALONG/NORTH OF I-90 THROUGH MIDDAY.
TEMPERATURES SHOULD REBOUND A BIT FROM WEEKEND CHILL AS WARMER LOW
LEVEL AIR BEGINS TO WORK INTO THE AREA THIS AFTERNOON. STILL ONE
MORE DAY BELOW NORMAL THOUGH... WITH HIGHS IN THE TEENS TO LOWER
20S. ONE THING OF NOTE ON TEMPS THROUGHOUT MUCH OF THE FORECAST...
NAM/GFS APPEAR TO HAVE POORLY INITIALIZED SNOW COVER IN THE MODEL...
WHICH SEEMS TO BE HAVING A LARGE EFFECT ON THEIR RESPECTIVE SURFACE
TEMPERATURE FORECASTS... SEEN BOTH IN THE RAW MODELS/MOS OUTPUT...
THOUGH SOMEWHAT LESSER EXTENT IN THE LATTER. THUS HAVE CHOSEN TO
FAVOR WARMER GEM/ECMWF TEMPERATURES THROUGH MOST OF THE WEEK...
ESPECIALLY THROUGH FRIDAY WHEN WARM AIR ALOFT REMAINS IN PLACE.
NEXT WAVE MOVES ACROSS THE REGION TUESDAY/TUESDAY NIGHT. STRONG WARM
ADVECTION WILL LEAD TO POTENTIAL FOR A LITTLE LIGHT SNOW OR FLURRIES
AHEAD OF THE WARM AIR...WHICH WILL SPREAD ACROSS THE FORECAST AREA
IN EARNEST TUESDAY NIGHT. LITTLE ACCUMULATION EXPECTED...WITH MAYBE
A QUARTER INCH OR SO ALONG THE HIGHWAY 14 CORRIDOR. STOUT SOUTHWEST
FLOW AHEAD OF THE WARM FRONT WILL RESULT IN GUSTY WINDS ATOP AND
DOWNSTREAM OF THE BUFFALO RIDGE MUCH OF THE NIGHT. EXPECT EARLY
EVENING LOWS FROM AROUND 20 IN THE EAST TO THE MID-UPPER 20S WEST OF
THE JAMES VALLEY...WITH MOST AREAS WARMING TO NEAR FREEZING OR JUST
SHY BY DAYBREAK WEDNESDAY AS WINDS TURN TO THE WEST BEHIND THE WARM
FRONT. STILL LOOKS LIKE A MILD DAY WITH TEMPS ONLY WARMING A FEW
MORE DEGREES THROUGH THE DAY TO HIGHS OF 35 TO 45.
BACKDOOR COOL FRONT DROPS THROUGH NORTHEAST PORTIONS OF THE FORECAST
AREA WEDNESDAY NIGHT/THURSDAY. TEMPERATURES STILL EXPECTED TO BE
ABOVE NORMAL THURSDAY THOUGH...WITH HIGHS UPPER 20S NORTHEAST TO THE
MID 30S THROUGH THE MISSOURI VALLEY. GEM/ECMWF BOTH SHOWING ANOTHER
WARM PUSH FRIDAY AHEAD OF STRONGER PUSH OF COLD AIR EXPECTED NEXT
WEEKEND. HAVE NUDGED TEMPERATURES A FEW DEGREES ABOVE GENERAL MODEL
CONSENSUS...THOUGH COULD BE EVEN WARMER IF 14/00Z ECMWF PANS OUT.
A COUPLE OF QUICK MOVING WAVES DIVE SOUTHEAST ACROSS NORTH DAKOTA
AND NORTHERN MINNESOTA DURING THE LONGER RANGE. THE FIRST WEAKER
WAVE MOVES THROUGH THURSDAY NIGHT...LEAVING A TIGHTENING THERMAL
GRADIENT WHICH NEXT STRONGER WAVE CAN WORK WITH SATURDAY. THIS WAVE
WILL PUSH THE ARCTIC FRONT SOUTH THROUGH THE REGION...BRINGING A
RETURN TO BELOW NORMAL TEMPERATURES BY THE LATTER HALF OF NEXT
WEEKEND. AS WAS MENTIONED ABOVE...ENERGY APPEARS TO REMAIN WELL
NORTH OF OUR AREA AT THIS TIME...SO WILL KEEP THE LONGER RANGE DRY
FOR NOW. HOWEVER WILL HAVE TO WATCH FOR POTENTIAL OF SOME LIGHT SNOW
SUNDAY AS YET ANOTHER WAVE DROPS INTO THE ARCTIC AIR MASS WHICH IS
EXPECTED TO PUSH BACK INTO THE REGION BY THEN.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
331 PM CST MON JAN 14 2013
.TONIGHT AND TUESDAY...FORECAST CONFIDENCE...HIGH
AN AREA OF LOW LEVEL CLOUDS WILL LIKELY AFFECT THE NORTHWEST HALF OF
THE FORECAST AREA LATE THIS AFTERNOON AND INTO TONIGHT. HIGH LEVEL
CLOUDS ARE POSSIBLE ELSEWHERE. THE LOW LEVEL CLOUDS SHOULD MOVE ON
OR SCATTER OUT BY LATE IN THE NIGHT...WITH SOME MID LEVEL CLOUDS
LINGERING TUESDAY MORNING. SKIES SHOULD BECOME MOSTLY SUNNY BY THE
AFTERNOON.
LOWS A LITTLE TRICKY TONIGHT...ALL DEPENDING ON HOW LONG CLOUDS
STICK AROUND...AS WINDS WILL BE LIGHT. GENERALLY WENT WITH A
CONSENSUS FOR LOWS...AS THE ECMWF/GFS/NAM SOLUTIONS NOT TOO FAR
APART. COULD SEE TEMPS GET A FEW DEGREES COLDER THAN EXPECTED IF
SKIES CLEAR UP SOONER THAN EXPECTED...RESULTING IN A LONGER PERIOD
OF GOOD RADIATIONAL COOLING CONDITIONS. HIGH TEMPS SHOULD BE BACK
AROUND NORMAL TUESDAY...MAYBE EVEN A DEGREE OR TWO ABOVE AVERAGE
VALUES FOR MID JANUARY.
.SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY.
MID TO UPPER LEVEL TROUGH AXES SHIFT EAST...WITH SHORT WAVE DROPPING
SE TUESDAY NIGHT/WEDNESDAY IN LEFT EXIT REGION OF UPPER LEVEL JET
MAX TOPPING WESTERN RIDGE AND NOSING INTO THE UPPER MIDWEST. AFTER
THIS WAVE CLEARS THE REGION...MODELS VARY IN PLACEMENT OF CHANNELED
VORTICITY IN CONFLUENT FLOW UNDER HUDSON BAY POLAR VORTEX FOR THE
REST OF THE SHORT TERM BUT GENERALLY KEEP IT TIED TO THE UPPER
JET...STAYING NORTH OF FORECAST AREA.
TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE MEDIUM.
TEMPERATURES FALL TUESDAY EVENING WITH READINGS HOLDING STEADY OR
RISING AFTER LOWS ARE REACHED AROUND MIDNIGHT AS SOUTHWEST WINDS
INCREASE AHEAD OF APPROACHING SHORT WAVE. LOCATION OF BEST FORCING
WITH WAVE VARIES WITH MODEL TRACK AND STRENGTH DIFFERENCES.
CONSENSUS KEEPS THE BETTER CHANCES FOR ACCUMULATING SNOW ACROSS NRN
WI...WHICH LEADS TO CHANCE OF LIGHT SNOW IN THE FAR NORTH AND SLIGHT
CHANCE ELSEWHERE MAINLY WEDNESDAY MORNING. BRIEF PERIOD OF LIFT AND
DEEP MOISTURE INTO THE DENDRITE GROWTH ZONE...ALONG WITH
PRECIPITABLE WATER ONLY REACHING 1/3 INCH SO DURING MOST FAVORABLE
TIME FOR PRECIPITATION...MEANS MINIMAL ACCUMULATIONS OF A FEW TENTHS
OF AN INCH AT MOST.
GUSTY WINDS ON WEDNESDAY WITH TIGHT GRADIENT AROUND SOUTHERN CANADA
LOW. AGAIN A CONSENSUS BLEND TEMPERING THE STRONGER NAM WINDS BUT
THIS STILL BRINGS 15 TO 25 MPH SOUTHWEST WINDS...SHIFTING WEST
BEHIND THE SURFACE TROUGH/COLD FRONT...WITH A FEW GUSTS TO 30 MPH.
THE GUSTY SOUTHWEST WINDS PUSH A THERMAL RIDGE AHEAD OF SURFACE
TROUGH OVER THE CWA MIDDAY...WITH BLENDED TEMPERATURES BRINGING
HIGHS IN THE LOWER TO MIDDLE 30S...THOUGH TEMPS COULD BE LOWER IF
FASTER MOVEMENT OF COLD FRONT REFLECTED IN THE GFS AND GEMNH OCCURS.
WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
WEST-NORTHWEST FLOW BEHIND LOW SHUNTS COLDEST AIR OFF TO THE
NORTHEAST OF THE REGION OVER SOUTHEAST CANADA...BUT ENOUGH COLD AIR
ADVECTION TO BRING SINGLE DIGIT LOWS TO THE NORTH WEDNESDAY
NIGHT...WITH MID-TEENS IN THE SOUTH. HIGH PRESSURE BRINGS QUIET
WEATHER WITH NEUTRAL TEMPERATURE ADVECTION BRINGING HIGHS IN THE
TEENS NORTH TO LOWER 20S SOUTH.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY. FORECAST CONFIDENCE
LOW TO MEDIUM.
WEAK WAVES PASSING BY TO THE NORTH IN THE NEAR ZONAL FLOW LIFT
850/925MB TEMPERATURES ENOUGH TO WARM HIGHS INTO THE LOWER TO MIDDLE
30S FOR FRIDAY AND SATURDAY. FAR NORTH MAY BE BRUSHED BY LIGHT SNOW
WITH THE WARM ADVECTION PUSH THURSDAY NIGHT...AND ONLY A LITTLE
BETTER CHANCE SATURDAY/SATURDAY NIGHT WITH STRONGER WAVE CROSSING
NORTHERN WISCONSIN. COLD ADVECTION AROUND ARCTIC HIGH SETTLING INTO
THE PLAINS BEHIND THIS LAST WAVE BRINGS HIGHS IN THE TEENS
SUNDAY...WITH SINGLE DIGIT LOWS SUNDAY NIGHT. BLENDED HIGHS ON LY IN
THE SINGLE DIGITS TO LOWER TEENS MONDAY...THEN FALLING TO BELOW
ZERO AWAY FROM LAKE MICHIGAN MONDAY NIGHT. IF COLDER GFS PANS
OUT...READINGS COULD GET EVEN COLDER.
&&
.AVIATION/00Z TAFS/...
STILL WATCHING AN AREA OF MVFR CIGS UPSTREAM. LATEST RAP AND NAM RH
FIELDS INDICATE THIS MAY HOLD TOGETHER AND MOVE INTO THE NORTHWEST
HALF OF THE FORECAST AREA MID TO LATE THIS AFTERNOON. BEST CHANCE
FOR THESE LOWER CIGS APPEARS TO BE ROUGHLY ALONG AND NORTHWEST OF A
MINERAL POINT TO SHEBOYGAN LINE...AS THE HIGH RH IN THE MODELS NEVER
QUITE MAKES IT TO THE SOUTHEAST. WILL CONTINUE TO KEEP AN EYE ON
SATELLITE TRENDS AND MODIFY TAFS AS NEEDED.
ANY LOWER CIGS SHOULD SCATTER OUT OR MOVE OUT BY MORNING...WITH VFR
CONDITIONS THEN EXPECTED THROUGH THE DAY TUESDAY.
&&
.MARINE...
SOUTHWEST WINDS WILL INCREASE TUESDAY NIGHT AHEAD OF AN APPROACHING
TROUGH OF LOW PRESSURE. WIND GUSTS ARE EXPECTED TO PEAK IN THE 30-35
KT RANGE LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING. MODELS
CURRENTLY INDICATING GUSTS RIGHT ON THE VERGE OF GALE
FORCE...ESPECIALLY TOWARD OPEN WATERS...SO WILL GO WITH A GALE WATCH
FOR THIS PERIOD OF HIGHER GUSTS. WILL LIKELY SEE GUSTS TO SMALL
CRAFT LEVELS EARLIER IN THE NIGHT AS THINGS RAMP UP...AND INTO
WEDNESDAY AFTERNOON AS WINDS EASE.
THE HIGHEST WAVES WILL BE ACROSS THE NORTH AND TOWARD OPEN WATERS
DUE TO THE EXPECTED SOUTHWEST FLOW. NOT EXPECTING WAVES WILL GET
PARTICULARLY HIGH GIVEN THE OFFSHORE COMPONENT TO THE WINDS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...GALE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING FOR
LMZ643>646.
&&
$$
TONIGHT/TUESDAY AND AVIATION/MARINE...DDV
TUESDAY NIGHT THROUGH MONDAY...REM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1128 AM CST MON JAN 14 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY
322 AM CST MON JAN 14 2013
AT 3 AM...A SURFACE TROUGH WAS LOCATED ACROSS SOUTHWEST MINNESOTA.
THIS TROUGH IS CURRENTLY PRODUCING A MVFR DECK OF CLOUDS ACROSS
EASTERN SOUTH DAKOTA AND SOUTHWEST MINNESOTA. THERE ARE EVEN
FLURRIES BEING REPORTED AT SIOUX FALLS SOUTH DAKOTA. FURTHER TO
THE SOUTHWEST...THE WATER VAPOR IMAGERY SHOWS A SHORT WAVE TROUGH
MOVING OUT OF COLORADO. THIS SYSTEM HAS BEEN PRODUCING SOME LIGHT
SNOW FROM COLORADO INTO CENTRAL SOUTH DAKOTA. THE 14.00Z MODELS
ARE IN GOOD AGREEMENT THAT THE SURFACE TROUGH WILL MOVE SLOWLY
EAST AND GRADUALLY WEAKEN TODAY. MEANWHILE THE SHORT WAVE WILL
MOVE ACROSS THE AREA THIS AFTERNOON. BOTH THE GFS AND NAM/WRF
SOUNDINGS SHOW LITTLE OMEGA WITH THESE SYSTEMS. MEANWHILE THE RAP
HAS UP TO 5 MICROBARS OF OMEGA CO-LOCATED WITH THE DENDRITIC
GROWTH ZONE. SINCE BOTH SYSTEMS ARE CURRENTLY PRODUCING SOME
FLURRIES OR VERY LIGHT SNOW...WENT MORE TOWARD THE RAP AND
INTRODUCED SOME SCATTERED FLURRIES FOR THIS AFTERNOON NORTHWEST OF
SAINT ANSGAR IOWA TO WISCONSIN RAPIDS LINE.
ON TUESDAY NIGHT AND WEDNESDAY...THE MODELS CONTINUE TO SHOW THAT
A LOW PRESSURE SYSTEM WILL MOVE ALONG THE ARCTIC COLD FRONT TO OUR
NORTH. AS THE WAVE APPROACHES...THE CLOUDS WILL INCREASE OVERNIGHT
AND TEMPERATURES WILL SLOWLY RISE. LIKE THE PAST COUPLE OF
DAYS...THE MODELS CONTINUE TO SHOW THAT THERE WILL BE ENOUGH
MOISTURE FOR SOME PRECIPITATION TO DEVELOP ALONG AND NORTH OF THE
INTERSTATE 90 CORRIDOR OVERNIGHT TUESDAY AND WEDNESDAY MORNING.
HOWEVER SOUNDINGS CONTINUE TO STRUGGLE ON WHETHER THERE WILL BE
ICE CRYSTAL SEEDING OR NOT. IN MANY CASES...WHERE THEY SHOW THE
LACK OF ICE...THERE IS NO PRECIPITATION. SINCE THERE IS NO CLEAR
SIGNAL...JUST KEPT THE PRECIPITATION IN THE FORM OF SNOW FOR NOW.
HOWEVER A BIT CONCERNED THAT THERE MAY BE SOME LIGHT FREEZING
DRIZZLE ON THE SOUTHERN PERIPHERY OF THE PRECIPITATION.
ANOTHER CONCERN ON WEDNESDAY IS THE TEMPERATURES...THE NAM/WRF HAS
WAY TOO MUCH SNOW COVER IN IT. THIS MODEL SHOWED 1 TO 2 INCHES OF
SNOW ON THE GROUND ACROSS NORTHEAST IOWA AND SOUTHEAST
MINNESOTA...AND 2 TO 5 INCHES OF SNOW ACROSS WESTERN WISCONSIN.
COOPERATIVE REPORTS AND NOHRSC SHOW THAT WITH THE EXCEPTION OF AN
INCH AT MEDFORD WISCONSIN...MUCH OF THE AREA IS SNOW FREE. DUE TO
THIS...THE NAM/WRF TEMPERATURES ARE WAY TOO COLD. TYPICALLY...AT
LA CROSSE THE MID-JANUARY MAXIMUM TEMPERATURES AVERAGE 10 DEGREES
WARMER THAN THE LONG TERM AVERAGE /24.7 DEGREES AT KLSE/ WHEN
THERE IS NO SNOW ON THE GROUND. THIS FITS IN WELL WITH A BLEND OF
THE GFS/ECMWF/GEM. WOULD NOT BE SURPRISED TO SEE SOME LOWER 40S
ACROSS SOUTHWEST WISCONSIN AND NORTHEAST IOWA.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
322 AM CST MON JAN 14 2013
ON THURSDAY AND THURSDAY NIGHT...THE 14.00Z MODELS CONTINUE TO
STRUGGLE ON HOW FAR SOUTH THE ARCTIC FRONT WILL GET. THE GFS HAS
THIS FRONT DROPPING SOUTH OF THE FORECAST AREA. MEANWHILE THE
NAM/WRF KEEPS THIS FRONT NORTH OF THE FORECAST AREA. THIS IS DUE
TO ANOTHER LOW PRESSURE SYSTEM QUICKLY FOLLOWING THE LOW THAT
PASSES TO THE NORTH OF THE AREA ON TUESDAY NIGHT AND WEDNESDAY.
MEANWHILE THE ECMWF IS A GOOD COMPROMISE BETWEEN THE TWO AND IT
HAS THIS FRONT ONLY GETTING AS FAR SOUTH AS THE INTERSTATE 94
CORRIDOR. DUE TO THESE DIFFERENCES...THERE IS LOWER THAN USUAL
CONFIDENCE IN THE TEMPERATURES. EVEN THE SNOWFALL FORECAST IS
UNCERTAIN DUE TO THE VARIOUS TIMING OF THE WAVES AND THE PLACEMENT
OF THE FRONT /THE SNOW WILL BE MAINLY CONFINED NORTH OF THIS
FRONT/.
ON FRIDAY...THE MODELS CONTINUE TO SHOW THAT A LOW PRESSURE AREA
WILL BE PASSING NORTH OF THE AREA. THE COMBINATION OF SOUTHWEST
WINDS AND SUNSHINE WILL ALLOW TEMPERATURES TO ONCE AGAIN WARM INTO
THE 30S AND LOWER 40S. THE ECMWF EVEN SUGGESTS LOWER AND MID 40S.
SINCE THIS HAS BEEN A CONSISTENT SIGNAL...RAISED THE ALL BLEND
TEMPERATURES BY ABOUT 5 DEGREES.
ON SUNDAY...THE MODELS CONTINUE TO STRUGGLE ON HOW FAR SOUTH THE
ARCTIC FRONT WILL SAG SOUTHWARD INTO THE AREA. A COUPLE OF DAYS
AGO THE ECMWF CONSISTENTLY SHOWED THAT THIS FRONT WOULD MOVE WELL
SOUTH OF THE AREA. THE 13.12Z ECMWF BACKED AWAY FROM THIS
SOLUTION...AND THE 14.00Z ECMWF HAS RETURNED BACK TO ITS COLDER
SOLUTION. SINCE THERE IS SOME UNCERTAINTY ON WHERE THIS FRONT WILL
BE LOCATED AND CONCERN ABOUT HOW MUCH MODERATION MAY TAKE PLACE
WITH THE LACK OF SNOW ACROSS THE AREA...JUST STAYED WITH THE ALL
BLEND FORECAST FOR NOW.
&&
.AVIATION...THROUGH 18Z TUESDAY
1128 AM CST MON JAN 14 2013
WEAK MID-LEVEL TROUGH WAS PUSHING BROKEN DECK OF VFR/MVFR
STRATOCUMULUS INTO THE AREA LATE THIS MORNING. EXPECT THIS CLOUD TO
LINGER THIS AFTERNOON WITH SCATTERED LIGHT FLURRY ACTIVITY. PLAN
ON THE CLOUDS TO ERODE THIS EVENING WITH LOSS OF SURFACE HEATING
AND INCREASING LOW-LEVEL SUBSIDENCE. VFR CONDITIONS THEN EXPECTED
THROUGH THE OVERNIGHT HOURS AND THROUGH TUESDAY AS SURFACE HIGH
PRESSURE BUILDS OVERHEAD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
322 AM CST MON JAN 14 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...DAS