AREA FORECAST DISCUSSION
NWS RENO NV
230 PM PST THU NOV 15 2007
.SHORT TERM...
STUBBORN INVERSION ACROSS SOME LOWER VALLEYS THIS AFTERNOON NEAR
RENO AND LOVELOCK. HOWEVER...MOST AREAS HAVE SEEN THE INVERSION LIFT
FROM CARSON CITY TO FALLON AND POINTS IN THE SIERRA. WHERE THE
INVERSION HAS LIFTED...HIGHS HAVE REACHED THE MID 60S TO LOWER 70S
WHILE THE RENO AIRPORT SITS IN THE UPPER 50S WHILE THE FOOTHILLS ARE
WELL INTO THE 60S.
AS FOR THE FORECAST...DO NOT EXPECT NEARLY AS STRONG AN INVERSION TO
DEVELOP TONIGHT AS THE NEXT SYSTEM MOVES INTO THE PACIFIC NW.
ABUNDANT MID AND HIGH CLOUD COVER WILL MOVE INTO THE AREA BY
MIDNIGHT LIMITING COOLING. SOME OF THESE CLOUDS ARE ALREADY INTO
EXTREME NW NV. HAVE KEPT LOWS A FEW DEGREES ABOVE GUIDANCE TONIGHT.
TOMORROW...TAIL END OF SYSTEM WILL STALL NEAR THE OREGON BORDER WITH
CLOUDS HANGING AROUND MOST AREAS. WINDS ALOFT WILL NOT BE QUITE AS
STRONG...AND WITH SOME SLIGHT COOLING ALOFT AND WARMER STARTING
TEMPS INVERSIONS ARE MUCH LESS A CONCERN TOMORROW. A SIMILAR
SCENARIO FOR FRI NIGHT AND SAT AS ANOTHER SYSTEM MOVES INTO THE NW.
HOWEVER...THIS SYSTEM HAS LESS MOISTURE TO WORK WITH EVEN THOUGH IT
WILL BE SLIGHTLY FURTHER SOUTH. EXPECT FEWER CLOUDS WITH A BIT MORE
COOLING AT NIGHT OVER TONIGHT. WILL KEEP THE SLIGHT CHC MENTION FOR
A SHOWER OR TWO NEAR THE OREGON BORDER.
MAIN PLAYER WILL BE THE SYSTEM PROGGED FOR LATE SUN INTO SUNDAY
NIGHT AS A STRONG RIDGE BEGINS TO BUILD IN THE EAST PACIFIC. MODELS
ARE FAIRLY CONSISTENT IN STRENGTH AND TIMING. EXPECT WINDS TO
INCREASE ON SUNDAY...ESPECIALLY NORTH OF I-80. DO NOT EXPECT A BIG
WIND EVENT BY ANY MEANS...ALTHOUGH AN ADVISORY MAY BE NECESSARY NEAR
THE OREGON BORDER DURING THE AFTERNOON IF A CRITICAL LEVEL NEAR 700
MB DOES DEVELOP. THE SYSTEM IS VERY DYNAMIC BUT WILL BE LOSING ITS
MOISTURE TAP AS IT MOVES IN SUNDAY NIGHT. AS A RESULT EXPECT THE
BEST CHANCES OF PRECIP ACROSS THE NORTHERN THIRD OF THE AREA. EXPECT
PRECIP TO HAVE NO PROBLEMS SPILLING OVER AT THIS TIME WITH STRONG
FRONTOGENETICAL FORCING...WEAK STABILITY AND THE RIGHT ENTRANCE
REGION OF THE ANTICYCLONICALLY CURVED JET OVER THE AREA. HAVE
INCREASED POPS NORTHERN THIRD...BUT HAVE PRETTY MUCH LEFT ALONE
ELSEWHERE AS THE DYNAMICS AND MOISTURE NEVER PUSH MUCH FURTHER SOUTH
PER MODEL CONSENSUS FOR NOW. WALLMANN
.LONG TERM...MONDAY THROUGH THURSDAY...
LARGE SCALE PATTERN OVERVIEW...
THERE IS A BASIC CONSENSUS BETWEEN MODEL SOLUTIONS ON DEVELOPMENT OF
A LARGE/COLD TROF OVER THE WRN CONUS EARLY NEXT WEEK...HOWEVER THE
SOLUTIONS DIVERGE IN TERMS OF HOW PROGRESSIVE THE TROF BECOMES LATE
IN THE PERIOD. 12Z GFS AND MAJORITY OF ENSEMBLE MEMBERS SHOW TROF
KICKING EASTWARD WED-THU...WHILE 12Z ECMWF AND A HANDFUL OF NCEP ENS
MEMBERS SEPARATE OUT WAVE ENERGY INTO TWO TROFS...WITH SECOND WAVE
HELPING DEVELOP A NEAR CUTOFF OVER SOCAL/AZ.
TELECONNECTIONS WITH LARGE NEGATIVE ANOMALY N OF JAPAN DONT PROVIDE
A DEFINITIVE ANSWER...YIELDING SLIGHTLY BELOW NORMAL HEIGHTS/TEMPS
OVER WRN CONUS. NCEP RELATIVE MEASURE OF PREDICTABILITY CHARTS SHOW
LOW VALUES ASSOC WITH TROF...BUT IMPRESSIVELY HIGH VALUES WITH
UPSTREAM RIDGE OVER NERN PACIFIC. OVERALL CONFIDENCE IS REASONABLE
MONDAY BUT GOES DOWNHILL TUE-THU. WILL ASSUME THAT SOME FLAVOR OF
TROFINESS WILL REMAIN THE GREAT BASIN/SW CONUS DURING THE PERIOD BUT
THE EXACT STRUCTURE AM NOT SURE ABOUT.
DAILY DETAILS...
SHARP TROF FCST TO DROP SE INTO THE GREAT BASIN MONDAY SHOULD YIELD
ISOLD SHOWERS ACROSS PORTIONS OF THE CWA...ESPECIALLY IN THE NE
SECTIONS WHERE WEAKER STATIC STABILITY IS ANTICIPATED. CLOSER TO THE
SIERRA...700MB FLOW TURNS MORE NELY MON NIGHT AND THERE MAY BE A
WINDOW WITH SUFFICIENT MOISTURE WHERE SOME UPSLOPE -SHSN COULD
DEVELOP...ESPECIALLY INTO MONO COUNTY.
EITHER WAY DURING MUCH OF THE LONG TERM...TEMPERATURES WILL BE MUCH
COLDER THAN NORMAL WITH 700MB TEMPS NEARING -14C TUE-THU DEPENDING
ON SPECIFIC MODEL SOLUTIONS. NE FLOW WILL DEVELOP BEHIND INITIAL
TROF PASSAGE...AND SPEEDS SHOULD GET PRETTY STRONG TUE-WED. BOTH
GFS/ECMWF ARE SHOWING POTENTIAL FOR STRONG EAST WIND EVENT AT TAHOE
SOMETIME DURING THIS PERIOD...WITH IMPRESSIVE INVERSION ~700-650MB.
IN ADDITION SHOULD ECMWF VERIFY...THEN A SECONDARY INSIDE SLIDER
SHORT WAVE COULD PRODUCE SNOW ACROSS THE CWA TUE NIGHT OR WED...
ESPECIALLY ON EAST/NE FACING SLOPES. BUT WITH DIFFERENCES IN MODELS
WILL NOT BITE ON THAT YET...SOMETHING TO WATCH THOUGH.
CS
&&
.AVIATION...
STRONG INVERSION SEEN IN ACARS DATA HELPED KEEP WINDS LIGHT ACROSS
WRN NV VALLEYS THUS FAR TODAY...WITH LOCATIONS AT/ABOVE INVERSION
HEIGHT SUCH AS TRK/TVL SEEING S/SW WINDS KICK IN EARLIER THIS AFTN.
HAZE LAYER AROUND RNO FINALLY BEGINNING TO MIX OUT AS OF 22Z.
OTHERWISE EXPECTING SCT-BKN MID TO HIGH LEVEL CLOUDS TO AFFECT THE
TAF SITES THROUGH 0Z/SAT. COULD BE SOME VSBY RESTRICTIONS AT TRK
AGAIN AFTER 5Z TONIGHT...THOUGH WITH POTENTIAL FOR INCREASED CLOUD
COVER HAVE NOT GONE TOO LOW WITH VSBY FCSTS.
CS
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&
$$
HTTP://WEATHER.GOV/RENO
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
230 PM PST WED NOV 14 2007
.SYNOPSIS...WEAKENING OFFSHORE FLOW WILL CONTINUE CLEAR SKIES WITH A
LITTLE COOLING THURSDAY. MORE COOLING FRIDAY THROUGH THE WEEKEND AS
WEAK ONSHORE FLOW RETURNS. A REDEVELOPING MARINE LAYER WILL BRING
AREAS OF COASTAL LOW CLOUDS AND FOG IN THE NIGHTS AND MORNINGS
FRIDAY THROUGH MONDAY...OTHERWISE FAIR. OFFSHORE FLOW SHOULD DEVELOP
AROUND THE MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...FOR SOUTHWEST CALIFORNIA INCLUDING SAN DIEGO...
ORANGE...SOUTHWEST SAN BERNARDINO AND WEST RIVERSIDE COUNTIES.
.SHORT TERM (TODAY-SAT)...CLEAR SKIES TODAY. EARLY AFTERNOON ACARS
SOUNDINGS INDICATE LIGHT WINDS IN THE LOW LEVELS WITH GRADUALLY
INCREASING NE WINDS ALOFT. OFFSHORE GRADIENTS WITH ABOUT -5 MB
SAN-LAS.
THE UPPER LOW OFF THE CENTRAL BAJA COAST WILL DRIFT E AND UPPER
RIDGING WILL PREVAIL OVER SRN CA. OFFSHORE GRADIENTS WILL GRADUALLY
WEAKEN AND TURN ONSHORE BY FRI AND SAT. THIS WILL MAINTAIN GENERALLY
CLEAR SKIES THROUGH THU. COOLER W OF THE MOUNTAINS THU. THE COOLING
WILL SPREAD FARTHER INLAND FRI AND SAT. A SHALLOW MARINE LAYER
SHOULD REFORM LATE THU NIGHT AND FRI MORNING WITH A POSSIBLE WEAK
EDDY. THE MARINE LAYER SHOULD DEEPEN A LITTLE FRI NIGHT INTO SAT
MORNING...BUT WILL STILL MAINLY BE CONFINED TO THE COASTAL AREAS.
THERE SHOULD ALSO BE A FEW HIGH CLOUDS FRI INTO SAT IN WINDS ALOFT.
&&
.LONG TERM (SUN-WED)...MINOR CHANGES SUN EXCEPT SLIGHTLY WARMER IN
MOST AREAS. AN UPPER TROUGH SHOULD MOVE PAST TO THE N MON BRINGING A
LITTLE COOLING AND A DEEPER MARINE LAYER WITH LOCAL GUSTY NW WINDS
IN THE MOUNTAINS AND DESERTS. THE FLOW WILL TURN OFFSHORE FROM THE N
TO NE TUE AND WED AND COULD BE A STRONG OFFSHORE EVENT. THIS SHOULD
BE A COOL DRY OFFSHORE FLOW. HOWEVER...THE EXACT STRENGTH AND TIMING
OF OFFSHORE WINDS ARE STILL UNCERTAIN.
&&
.AVIATION...
142130Z...NO SIGNIFICANT AVIATION WEATHER CONCERNS FOR NEXT 24
HOURS. DENSE FOG/LOW STRATUS MAY RETURN TO COAST LATE THURSDAY
AFTERNOON AFTER 15/2200 UTC. UNTIL THEN AIR MASS CONTINUES DRY AND
STABLE WITH EAST TO NORTHEAST WINDS 10 KT ABOVE FL020...BELOW THIS
LEVEL WINDS W-NW 5-10KT UNTIL 0100 UTC DUE TO SEA BREEZE.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...DVA
AVIATION...BALFOUR
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1205 PM EST WED NOV 14 2007
.AVIATION...DISCUSSION FOR 141800Z TAF ISSUANCE. NARROW AREA OF POST
FRONTAL MVFR CIGS ARND 020 AFFECTING THE KBMG TERMINAL SHOULD CLR
OUT OF THE THAT AREA BY ISSUANCE TIME. OTRW...ONLY A FEW DIURNAL
TYPE CLDS BASED 020-030 XPCTD FOR THE AFT HRS...WITH LYRD CLDS AOA
050 THRU 150600Z.
MEAN WND PROGS IN THE LWR LVLS SUGGEST A FEW SFC WND GUSTS 15-20 KTS
PSBL FM THE WNW TIL SUNSET.
&&
.PREV DISCUSSION...FORECAST FOCUS WILL BE ON PRECIP TODAY AND THEN
TIMING OF FROPA.
AGAIN THE NAM/GFS ARE SIMILAR ENOUGHTO USE A BLEND.
TEMPS HAVE BEEN RISING OVERNIGHT AS WARM ADVECTION HAS PUSHED
READINGS INTO THE UPPER 50S AND LOW 60S. ACARS DATA SHOWS A VERY
STRONG INVERSION AROUND 875MB WHICH WAS HOLDING LOW STRATUS DECK IN
PLACE THIS MORNING. SCATTERED RW AND DZ WAS MOVING EAST ACROSS THE
CWA AT 08Z AND THIS WILL LIKELY CONTINUE THROUGH MID MORNING. SOME
CLEARING WAS MAKING INTO EASTERN ILLINOIS AND THIS WILL SPREAD INTO
INDIANA AS THE FRONT GETS CLOSER AND HELPS BREAK THE INVERSION.
COLD ADVECTION WILL BEGIN LATER THIS MORNING AS THE FRONT GETS
CLOSER TO CENTRAL INDIANA. THE WIND WILL SHIFT TO THE WEST THEN NW
THIS AFTERNOON AND THEN THE COLD AIR FOLLOWS LATER TONIGHT. LOWS
TONIGHT WILL BE 15-20 DEGREES COLDER IN THE MID 30S THAN CURRENT
OVERNIGHT TEMPS IN THE MID TO UPPER 50S.
THURSDAY...COLDER TEMPS CAN BE EXPECTED AS THE H5 TROF SWINGS EAST
OF THE STAT. H85 TEMPS WILL BE AROUND -6C TO -8C OVER INDIANA
RESULTING IN HIGHS IN THE 40S WITH PARTLY TO MOSTLY CLOUDY SKIES.
FRIDAY THROUGH SATURDAY...DRY AND BELOW NORMAL TEMPS CAN BE
EXPECTED. SFC HIGH PRESSURE WILL MOVE FROM THE SOUTHERN PLAINS
SOUTHEAST TO THE EASTERN SEA BOARD BY SATURDAY. A WEAK FRONT WILL
WASH OUT OVER INDIANA ON SATURDAY AND WITH NO MOISTURE TO WORK WITH
PRECIP IS NOT EXPECTED.
SUNDAY...NO CHANGES MADE TO THE PREVIOUS FCST. AN H5 TROF AND SFC
WAVE PASS THROUGH THE STATE AND WITH SOME MOISTURE TO WORK WITH
THERE IS A CHANCE FOR RAIN ON SUNDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...SALLY
AVIATION...JAS
AREA FORECAST DISCUSSION...CORRECTED
NWS INDIANAPOLIS IN
554 AM EST WED NOV 14 2007
.AVIATION...DISCUSSION FOR 12Z TAFS
SATELLITE LOOP AND SFC OBS WERE FAVORING THE QUICKER CLRG IMPLIED BY
THE 00Z NAM AS SEEN IN THE TIME SECS AND LOW LVL RH PROGS. LAF WAS
ALREADY ABOUT TO CLR OUT AT 10Z AND HUF AND IND WERE ABOUT TO SEE A
FEW BREAKS. ACARS AND MODEL TIME SECS SHOWING STG INVERSION AROUND
850 MB BEING COMPLETELY WIPED OUT AS THE CD FNT...CURRENTLY FM NERN
IL INTO SWRN MO...REACHES LAF AROUND 12Z...HUF AND IND AROUND 13Z
AND BMG AROUND 15Z BASED ON STEADY SE MOVEMENT OF THE FNT. SO...MVFR
CIGS AND VSBYS WL BE OVER WITH RIGHT AFTER FROPA. CU DEVELOPMENT
PROGS WERE HINTING AT EARLY AFTERNOON SCT CU AT BMG AND LAF.
OTHEWISE...MID DECK EXPECTED TO MOVE IN THIS AFTERNOON BASED ON
MODEL TIME SECS AND UPSTREAM AC DECK ACRS SRN PARTS OF IA AND NE.
FINALLY...SC DECK CURRENTLY ACRS THE UPR MIDWEST IS EXPECTED TO
SPREAD ACRS THE TAF SITES OVERNGT...BUT TIME SECS FAVOR MOSTLY VFR
EXPECT PERHAPS SOME MVFR TOWARD 12Z AT LAF.
&&
.PREV DISCUSSION...FORECAST FOCUS WILL BE ON PRECIP TODAY AND THEN
TIMING OF FROPA.
AGAIN THE NAM/GFS ARE SIMILAR ENOUGHTO USE A BLEND.
TEMPS HAVE BEEN RISING OVERNIGHT AS WARM ADVECTION HAS PUSHED
READINGS INTO THE UPPER 50S AND LOW 60S. ACARS DATA SHOWS A VERY
STRONG INVERSION AROUND 875MB WHICH WAS HOLDING LOW STRATUS DECK IN
PLACE THIS MORNING. SCATTERED RW AND DZ WAS MOVING EAST ACROSS THE
CWA AT 08Z AND THIS WILL LIKELY CONTINUE THROUGH MID MORNING. SOME
CLEARING WAS MAKING INTO EASTERN ILLINOIS AND THIS WILL SPREAD INTO
INDIANA AS THE FRONT GETS CLOSER AND HELPS BREAK THE INVERSION.
COLD ADVECTION WILL BEGIN LATER THIS MORNING AS THE FRONT GETS
CLOSER TO CENTRAL INDIANA. THE WIND WILL SHIFT TO THE WEST THEN NW
THIS AFTERNOON AND THEN THE COLD AIR FOLLOWS LATER TONIGHT. LOWS
TONIGHT WILL BE 15-20 DEGREES COLDER IN THE MID 30S THAN CURRENT
OVERNIGHT TEMPS IN THE MID TO UPPER 50S.
THURSDAY...COLDER TEMPS CAN BE EXPECTED AS THE H5 TROF SWINGS EAST
OF THE STAT. H85 TEMPS WILL BE AROUND -6C TO -8C OVER INDIANA
RESULTING IN HIGHS IN THE 40S WITH PARTLY TO MOSTLY CLOUDY SKIES.
FRIDAY THROUGH SATURDAY...DRY AND BELOW NORMAL TEMPS CAN BE
EXPECTED. SFC HIGH PRESSURE WILL MOVE FROM THE SOUTHERN PLAINS
SOUTHEAST TO THE EASTERN SEA BOARD BY SATURDAY. A WEAK FRONT WILL
WASH OUT OVER INDIANA ON SATURDAY AND WITH NO MOISTURE TO WORK WITH
PRECIP IS NOT EXPECTED.
SUNDAY...NO CHANGES MADE TO THE PREVIOUS FCST. AN H5 TROF AND SFC
WAVE PASS THROUGH THE STATE AND WITH SOME MOISTURE TO WORK WITH
THERE IS A CHANCE FOR RAIN ON SUNDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...SALLY
AVIATION...MK
CLRG TIMING CORRECTED
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
545 AM EST WED NOV 14 2007
.AVIATION...DISCUSSION FOR 12Z TAFS
SATELLITE LOOP AND SFC OBS WERE FAVORING THE QUICKER CLRG IMPLIED BY
THE 00Z NAM AS SEEN IN THE TIME SECS AND LOW LVL RH PROGS. LAF WAS
ALREADY ABOUT TO CLR OUT AT 10Z AND HUF AND IND WERE ABOUT TO SEE A
FEW BREAKS. ACARS AND MODEL TIME SECS SHOWING STG INVERSION AROUND
850 MB BEING COMPLETELY WIPED OUT AS THE CD FNT...CURRENTLY FM NERN
IL INTO SWRN MO...REACHES LAF AROUND 12Z...HUF AND IND AROUND 14Z
AND BMG AROUND 16Z BASED ON STEADY SE MOVEMENT OF THE FNT. SO...MVFR
CIGS AND VSBYS WL BE OVER WITH RIGHT AFTER FROPA. CU DEVELOPMENT
PROGS WERE HINTING AT EARLY AFTERNOON SCT CU AT BMG AND LAF.
OTHEWISE...MID DECK EXPECTED TO MOVE IN THIS AFTERNOON BASED ON
MODEL TIME SECS AND UPSTREAM AC DECK ACRS SRN PARTS OF IA AND NE.
FINALLY...SC DECK CURRENTLY ACRS THE UPR MIDWEST IS EXPECTED TO
SPREAD ACRS THE TAF SITES OVERNGT...BUT TIME SECS FAVOR MOSTLY VFR
EXPECT PERHAPS SOME MVFR TOWARD 12Z AT LAF.
&&
.PREV DISCUSSION...FORECAST FOCUS WILL BE ON PRECIP TODAY AND THEN
TIMING OF FROPA.
AGAIN THE NAM/GFS ARE SIMILAR ENOUGHTO USE A BLEND.
TEMPS HAVE BEEN RISING OVERNIGHT AS WARM ADVECTION HAS PUSHED
READINGS INTO THE UPPER 50S AND LOW 60S. ACARS DATA SHOWS A VERY
STRONG INVERSION AROUND 875MB WHICH WAS HOLDING LOW STRATUS DECK IN
PLACE THIS MORNING. SCATTERED RW AND DZ WAS MOVING EAST ACROSS THE
CWA AT 08Z AND THIS WILL LIKELY CONTINUE THROUGH MID MORNING. SOME
CLEARING WAS MAKING INTO EASTERN ILLINOIS AND THIS WILL SPREAD INTO
INDIANA AS THE FRONT GETS CLOSER AND HELPS BREAK THE INVERSION.
COLD ADVECTION WILL BEGIN LATER THIS MORNING AS THE FRONT GETS
CLOSER TO CENTRAL INDIANA. THE WIND WILL SHIFT TO THE WEST THEN NW
THIS AFTERNOON AND THEN THE COLD AIR FOLLOWS LATER TONIGHT. LOWS
TONIGHT WILL BE 15-20 DEGREES COLDER IN THE MID 30S THAN CURRENT
OVERNIGHT TEMPS IN THE MID TO UPPER 50S.
THURSDAY...COLDER TEMPS CAN BE EXPECTED AS THE H5 TROF SWINGS EAST
OF THE STAT. H85 TEMPS WILL BE AROUND -6C TO -8C OVER INDIANA
RESULTING IN HIGHS IN THE 40S WITH PARTLY TO MOSTLY CLOUDY SKIES.
FRIDAY THROUGH SATURDAY...DRY AND BELOW NORMAL TEMPS CAN BE
EXPECTED. SFC HIGH PRESSURE WILL MOVE FROM THE SOUTHERN PLAINS
SOUTHEAST TO THE EASTERN SEA BOARD BY SATURDAY. A WEAK FRONT WILL
WASH OUT OVER INDIANA ON SATURDAY AND WITH NO MOISTURE TO WORK WITH
PRECIP IS NOT EXPECTED.
SUNDAY...NO CHANGES MADE TO THE PREVIOUS FCST. AN H5 TROF AND SFC
WAVE PASS THROUGH THE STATE AND WITH SOME MOISTURE TO WORK WITH
THERE IS A CHANCE FOR RAIN ON SUNDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...SALLY
AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
331 AM EST WED NOV 14 2007
.DISCUSSION...FORECAST FOCUS WILL BE ON PRECIP TODAY AND THEN
TIMING OF FROPA.
AGAIN THE NAM/GFS ARE SIMILAR ENOUGHTO USE A BLEND.
TEMPS HAVE BEEN RISING OVERNIGHT AS WARM ADVECTION HAS PUSHED
READINGS INTO THE UPPER 50S AND LOW 60S. ACARS DATA SHOWS A VERY
STRONG INVERSION AROUND 875MB WHICH WAS HOLDING LOW STRATUS DECK IN
PLACE THIS MORNING. SCATTERED RW AND DZ WAS MOVING EAST ACROSS THE
CWA AT 08Z AND THIS WILL LIKELY CONTINUE THROUGH MID MORNING. SOME
CLEARING WAS MAKING INTO EASTERN ILLINOIS AND THIS WILL SPREAD INTO
INDIANA AS THE FRONT GETS CLOSER AND HELPS BREAK THE INVERSION.
COLD ADVECTION WILL BEGIN LATER THIS MORNING AS THE FRONT GETS
CLOSER TO CENTRAL INDIANA. THE WIND WILL SHIFT TO THE WEST THEN NW
THIS AFTERNOON AND THEN THE COLD AIR FOLLOWS LATER TONIGHT. LOWS
TONIGHT WILL BE 15-20 DEGREES COLDER IN THE MID 30S THAN CURRENT
OVERNIGHT TEMPS IN THE MID TO UPPER 50S.
THURSDAY...COLDER TEMPS CAN BE EXPECTED AS THE H5 TROF SWINGS EAST
OF THE STAT. H85 TEMPS WILL BE AROUND -6C TO -8C OVER INDIANA
RESULTING IN HIGHS IN THE 40S WITH PARTLY TO MOSTLY CLOUDY SKIES.
FRIDAY THROUGH SATURDAY...DRY AND BELOW NORMAL TEMPS CAN BE
EXPECTED. SFC HIGH PRESSURE WILL MOVE FROM THE SOUTHERN PLAINS
SOUTHEAST TO THE EASTERN SEA BOARD BY SATURDAY. A WEAK FRONT WILL
WASH OUT OVER INDIANA ON SATURDAY AND WITH NO MOISTURE TO WORK WITH
PRECIP IS NOT EXPECTED.
SUNDAY...NO CHANGES MADE TO THE PREVIOUS FCST. AN H5 TROF AND SFC
WAVE PASS THROUGH THE STATE AND WITH SOME MOISTURE TO WORK WITH
THERE IS A CHANCE FOR RAIN ON SUNDAY.
&&
.AVIATION...DISCUSSION FOR 06Z TAFS
SRLY WINDS HAVE ADVECTED LOW STRATUS NORTH ACROSS ALL TAF SITES THIS
TUESDAY EVENING. LOOKING UPSTREAM ACROSS IL AND ERN MO SIMILAR
CONDITIONS EXIST. EVENING MODEL RUNS INCLUDING MOS INDICATE LOW
STRATUS SHOULD PREVAIL UNTIL NEAR FROPA WHICH IS EXPECTED 13Z-16Z.
IN ADDITION TO DECKS BELOW 1000FT...ISSUE OF HOW DENSE FOG WOULD
BECOMES REMAINS PROBLEMATIC. UPSTREAM OBS VARY FROM MVFR TO LIFR.
EXPECTATION IS FOR TREND OF LOWERING VSBY AT TAFS SIGHTS TO 3-4SM AT
KIND AND KLAF TO 2SM KBMG AND KHUF. DISTINCTION BASED ON BMG AND HUF
REMAINED UNDER STRATUS MOST OF TUESDAY WITH LITTLE DRYING WHILE KIND
AND KLAF HAD SUNSHINE ALL DAY TUESDAY ALLOWING FOR BETTER DRYING AND
LOWER DEWPOINTS INITIALLY.
ONCE FRONT MOVES THRU SOUNDINGS SHOW DECKS BELOW 1000FT QUICKLY LIFT
WHILE SFC OBS BACK MINNESOTA WAY SHOW DECKS AROUND 6000FT WHICH
SHOULD PUSH IN TO TAF SITES MID DAY AFTER BRIEF SCT 1500FT DECKS
14Z-18Z. VSBYS BECOME UNRESTRICTED AS DECKS LIFT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...SALLY
AVIATION...DT
AREA FORECAST DISCUSSION...CORRECTED
NWS DETROIT/PONTIAC MI
449 PM EST WED NOV 14 2007
CORRECTED WATCHES/WARNINGS/ADVISORIES SECTION
.SHORT TERM...TONIGHT
A GOOD DEAL OF SUNSHINE LATE THIS MORNING/EARLY THIS AFTERNOON
HELPED OFFSET THE MODEST LOW LEVEL COLD ADVECTION TODAY...ALLOWING
MAX TEMPS TO REACH TO AROUND 60 DEGREES WITHIN THE WELL MIXED
BOUNDARY LAYER (ABOVE 850 MB PER DTW TAMDAR SOUNDINGS) OVER
SOUTHEAST MICHIGAN.
DIGGING (BECOMING NEUTRALLY TILTED) UPPER LEVEL TROUGH AXIS TO PUSH
INTO THE WESTERN GREAT LAKES TONIGHT...WITH THE BROAD ASCENT OUT
AHEAD OF THIS TROUGH LEADING TO THE MID/UPPER LEVEL CLOUDS NOW
STREAMING THROUGH LOWER MICHIGAN. WILL NEED TO RELAY MORE ON THE
SECONDARY COLD FRONT/COLD CORE MOVING OVER LAKE MICHIGAN TO GENERATE
PRECIPITATION. INCREASING CHANCE OF INSTABILITY SNOW/RAIN SHOWERS
TOWARD 12Z THURSDAY...AS 850 MB TEMPS FALL TO -4C TO -6C. WET BULB
ZERO HEIGHTS LOOK TO BE 500 TO 1000 FEET...PER NAM BUFKIT SOUNDINGS.
BASED ON NAM/GFS 700 MB RH FIELDS (INDICATIVE OF DEEPER MOISTURE AND
ICE NUCLEATION) BEST CHANCE OF PRECIPITATION BY 12Z THURSDAY OVER
TRI-CITIES (40+ POP) WITH JUST A SLIGHT CHANCE TOWARD THE CITY OF
DETROIT/OHIO BORDER.
MIN TEMPS LOOK TO REMAIN JUST ABOVE FREEZING DUE TO CLOUDS AND
BOUNDARY LAYER STAYING FAIRLY WELL MIXED.
&&
.LONG TERM...THURSDAY THROUGH NEXT WEDNESDAY
THROUGH SATURDAY...
MODEL CONSENSUS AT 500 MB SHOWS A SHARP TROUGH PIVOTING TO THE EAST
THURSDAY...THEN ANOTHER TROUGH/VORTICITY LOBE SWINGING ON DOWN FROM
THE NORTH SATURDAY. AT THE SURFACE...A SECONDARY TROUGH/WELL DEFINED
CYCLONIC FLOW MOVING ACROSS THE AREA THURSDAY...WITH RIDGE BUILDING
IN FRIDAY. A WEAK CLIPPER THEN DIVING FROM THE NORTHERN PLAINS TO
OHIO AREA SATURDAY...PULLING A WEAK TROUGH SOUTHWARD ACROSS THE
FORECAST AREA.
MOISTURE IN THE 850 TO 500 MB LAYER MODESTLY GOOD THROUGH
THURSDAY...THEN DRIER UNTIL BETTER LATE FRIDAY OR FRIDAY NIGHT
THROUGH SATURDAY. 925 MB MOISTURE QUITE GOOD THURSDAY AND THURSDAY
NIGHT...THEN WANING UNTIL BEEFING UP AGAIN BY SATURDAY.
LITTLE TO NO LOW TO MID LEVEL OMEGA ASCENT UNTIL OCCASIONALLY SLIGHT
FRIDAY NIGHT AND SATURDAY. 850 TO 500 MB QVECTOR CONVERGENCE SLIGHT
THURSDAY...MODEST FRIDAY NIGHT AND SATURDAY. SURFACE WIND
CONVERGENCE SLIGHT MAINLY THURSDAY AND SATURDAY. WEAK 285K
ISENTROPIC ASCENT SEEN FRIDAY THROUGH SATURDAY...BUT CONDENSATION
PRESSURE DEFICITS ARE HIGH FRIDAY BEFORE THEN SHARPLY LOWER FRIDAY
NIGHT AND SATURDAY.
GIVEN THE RELATIVELY ELEVATED WET BULB ZERO HEIGHTS...WILL MENTION
SCATTERED RAIN/SNOW SHOWERS THURSDAY EXCEPT HIGHER POPS ON LAKE
HURON...AND CONTINUE CHANCE LIGHT SNOW SHOWER MENTION THUMB/LAKE
HURON IN MODEST LAKE EFFECT THURSDAY NIGHT/FRIDAY.
THEREAFTER...CHANCE OF SNOW SHOWERS OR MIX FRIDAY AND OF RAIN
SHOWERS OR MIX SATURDAY.
AFTER SATURDAY...
OVERALL LOW CONFIDENCE IN DETAILS OF FORECAST FOR THIS PERIOD...AS
MODEL DIFFERENCES CONTINUE LARGE...BOTH AMONG MODELS AND FROM RUN TO
RUN WITHIN MODELS.
AT 500 MB...SOME MODEL CONSENSUS TOWARD SHORTWAVE TROUGH PIVOTING
AWAY FROM THE NORTHERN/EASTERN GREAT LAKES REGION SATURDAY NIGHT
FOLLOWED BY A BIT OF RIDGING THROUGH SUNDAY. THEREAFTER...THE 00Z
GFS AND 06Z DGEX SHOWED NORTHERN STREAM ENERGY MAKING A DENT IN
HEIGHTS OVER THE LAKES REGION THROUGH MONDAY BEFORE RISING
HEIGHTS/RIDGING PREVAILS INTO MID WEEK AS WESTERN TROUGH EVOLVES.
THE 06Z GFS...BY STARK CONTRAST...SHOWED LESS OF A NORTHERN STREAM
DENT MONDAY AND MUCH FASTER EVOLUTION/PROGRESSION OF WESTERN TROUGH
AND BREAKDOWN OF RIDGE OVER THE GREAT LAKES. THIS 06Z SOLUTION WAS
LEANING TOWARD THE 00Z ECMWF. THE OVERNIGHT WRFHEMI EMPHASIZED A
HUGE EASTERN CANADIAN LOW AFFECTING THE LAKES REGION FOR MOST OF THE
PERIOD. THE 00Z GFS ENSEMBLE MEMBERS SHOWED MUCH DIVERSITY...
ESPECIALLY TOWARD MID WEEK.
AT THE SURFACE...SOME MODEL CONSENSUS OF A LARGE HIGH PRESSURE
SYSTEM CENTERED NEAR OR NORTH OF LAKE SUPERIOR AT THE START OF THE
PERIOD WITH SUBSEQUENT EASTWARD DRIFT THROUGH MONDAY. MODELS VARY
GREATLY AS TO HOW QUICK TO MOVE A COLD FRONT IN/THROUGH THE AREA
FROM THE WEST. THE 00Z WRFHEMI/00Z OPERATIONAL AND ENSEMBLE MEAN OF
THE GFS...AND 06Z DGEX SHOWED THIS FRONT IN THE AREA MONDAY AS
OPPOSED TO THE TUESDAY TIME FRAME AS PER ECMWF AND 06Z GFS. OVERALL
GROWING CONSENSUS EXISTS TOWARD HIGH PRESSURE HAVING TROUBLE NOSING
IN FROM THE NORTHERN PLAINS...AS FRONT STALLS OVER THE SOUTHERN
LAKES REGION AND ONE OR MORE WEAK WAVES MOVES NORTHEAST ALONG THE
FRONT. THIS LATTER IDEA EXPRESSED BY THE 00Z ECMWF AND ALSO THE 12Z
OPERATIONAL GFS.
THEREFORE...WILL CONTINUE WITH SLIGHT CHANCE LIGHT SNOW SHOWERS
SATURDAY NIGHT AND SUNDAY ESPECIALLY NEAR LAKE HURON FOR MODEST LAKE
EFFECT. THEN...CHANCE OF RAIN SHOWERS BEGINNING MONDAY NIGHT AND
CONTINUING THROUGH WEDNESDAY WITH FRONT AND PROBABLE WAVES ALONG THE
FRONT ALBEIT IN PRESENCE OF WARMER TEMPERATURES.
&&
.MARINE...
WESTERLY WIND GUSTS OF 20 TO 30 KNOTS THIS AFTERNOON ARE EXPECTED TO
DIMINISH A GOOD 5 KNOTS THIS EVENING/TONIGHT ALONG THE NEARSHORE
WATERS AS WE LOSE DAYTIME HEATING AND BOUNDARY LAYER COOLS. A
SECONDARY COLD FRONT PUSHING THROUGH THE CENTRAL GREAT LAKES
TOMORROW MORNING WILL BRING AN INCREASE TO THE WINDS BY
AFTERNOON...WITH SMALL CRAFT ADVISORY WINDS EXPECTED TO RETURN OVER
ALL MARINE AREAS. A RIDGE OF HIGH PRESSURE IS FORECASTED TO BUILD
INTO THE CENTRAL GREAT LAKES ON FRIDAY WITH WINDS BECOMING LIGHT.
LIGHT WINDS ARE EXPECTED TO PERSIST INTO SATURDAY AS A WEAK AREA OF
LOW PRESSURE TRAVERSES THROUGH THE SOUTHERN GREAT LAKES.
&&
.PREV DISCUSSION...ISSUED 1212 PM EST WED NOV 14 2007
AVIATION...
THE LOW LEVELS HAVE DRIED OUT EARLY THIS AFTERNOON...WHICH SHOULD
ALLOW FOR CLEAR SKIES (BELOW 12000 FEET) TO PERSIST INTO THE EVENING
HOURS. HOWEVER...WESTERLY WINDS WILL REMAIN GUSTY UP TO 25 KNOTS
THIS AFTERNOON BEFORE DECREASING. A SECONDARY COLD FRONT WILL
APPROACH SOUTHEAST MICHIGAN TONIGHT...BRINGING WITH IT A BROKEN
LOWER VFR STRATUS DECK (AROUND 4000 FEET) AFTER MIDNIGHT. ENOUGH
COLD AIR ARRIVES TOMORROW MORNING TO PRODUCE INSTABILITY SNOW/RAIN
SHOWERS OFF LAKE MICHIGAN...WHICH WILL LIKELY PRODUCE SCATTERED
MVFR VSBYS/CEILINGS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...LHZ422-LHZ442-LHZ443...UNTIL 7 PM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO
PORT HURON...FROM 10 AM THURSDAY TO 7 PM FRIDAY.
SMALL CRAFT ADVISORY...INNER SAGINAW BAY...FROM 10 AM THURSDAY TO
11 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR
BEACH...UNTIL 7 PM FRIDAY.
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY...UNTIL NOON FRIDAY.
LAKE ST CLAIR...
SMALL CRAFT ADVISORY...FROM 10 AM THURSDAY TO 11 PM THURSDAY.
MI WATERS OF LAKE ERIE...
SMALL CRAFT ADVISORY...FROM 10 AM THURSDAY TO 11 PM THURSDAY.
&&
$$
SHORT TERM...SF
LONG TERM....DWD
MARINE.......SF
AVIATION.....SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
353 PM EST WED NOV 14 2007
.SHORT TERM...TONIGHT
A GOOD DEAL OF SUNSHINE LATE THIS MORNING/EARLY THIS AFTERNOON
HELPED OFFSET THE MODEST LOW LEVEL COLD ADVECTION TODAY...ALLOWING
MAX TEMPS TO REACH TO AROUND 60 DEGREES WITHIN THE WELL MIXED
BOUNDARY LAYER (ABOVE 850 MB PER DTW TAMDAR SOUNDINGS) OVER
SOUTHEAST MICHIGAN.
DIGGING (BECOMING NEUTRALLY TILTED) UPPER LEVEL TROUGH AXIS TO PUSH
INTO THE WESTERN GREAT LAKES TONIGHT...WITH THE BROAD ASCENT OUT
AHEAD OF THIS TROUGH LEADING TO THE MID/UPPER LEVEL CLOUDS NOW
STREAMING THROUGH LOWER MICHIGAN. WILL NEED TO RELAY MORE ON THE
SECONDARY COLD FRONT/COLD CORE MOVING OVER LAKE MICHIGAN TO GENERATE
PRECIPITATION. INCREASING CHANCE OF INSTABILITY SNOW/RAIN SHOWERS
TOWARD 12Z THURSDAY...AS 850 MB TEMPS FALL TO -4C TO -6C. WET BULB
ZERO HEIGHTS LOOK TO BE 500 TO 1000 FEET...PER NAM BUFKIT SOUNDINGS.
BASED ON NAM/GFS 700 MB RH FIELDS (INDICATIVE OF DEEPER MOISTURE AND
ICE NUCLEATION) BEST CHANCE OF PRECIPITATION BY 12Z THURSDAY OVER
TRI-CITIES (40+ POP) WITH JUST A SLIGHT CHANCE TOWARD THE CITY OF
DETROIT/OHIO BORDER.
MIN TEMPS LOOK TO REMAIN JUST ABOVE FREEZING DUE TO CLOUDS AND
BOUNDARY LAYER STAYING FAIRLY WELL MIXED.
&&
.LONG TERM...THURSDAY THROUGH NEXT WEDNESDAY
THROUGH SATURDAY...
MODEL CONSENSUS AT 500 MB SHOWS A SHARP TROUGH PIVOTING TO THE EAST
THURSDAY...THEN ANOTHER TROUGH/VORTICITY LOBE SWINGING ON DOWN FROM
THE NORTH SATURDAY. AT THE SURFACE...A SECONDARY TROUGH/WELL DEFINED
CYCLONIC FLOW MOVING ACROSS THE AREA THURSDAY...WITH RIDGE BUILDING
IN FRIDAY. A WEAK CLIPPER THEN DIVING FROM THE NORTHERN PLAINS TO
OHIO AREA SATURDAY...PULLING A WEAK TROUGH SOUTHWARD ACROSS THE
FORECAST AREA.
MOISTURE IN THE 850 TO 500 MB LAYER MODESTLY GOOD THROUGH
THURSDAY...THEN DRIER UNTIL BETTER LATE FRIDAY OR FRIDAY NIGHT
THROUGH SATURDAY. 925 MB MOISTURE QUITE GOOD THURSDAY AND THURSDAY
NIGHT...THEN WANING UNTIL BEEFING UP AGAIN BY SATURDAY.
LITTLE TO NO LOW TO MID LEVEL OMEGA ASCENT UNTIL OCCASIONALLY SLIGHT
FRIDAY NIGHT AND SATURDAY. 850 TO 500 MB QVECTOR CONVERGENCE SLIGHT
THURSDAY...MODEST FRIDAY NIGHT AND SATURDAY. SURFACE WIND
CONVERGENCE SLIGHT MAINLY THURSDAY AND SATURDAY. WEAK 285K
ISENTROPIC ASCENT SEEN FRIDAY THROUGH SATURDAY...BUT CONDENSATION
PRESSURE DEFICITS ARE HIGH FRIDAY BEFORE THEN SHARPLY LOWER FRIDAY
NIGHT AND SATURDAY.
GIVEN THE RELATIVELY ELEVATED WET BULB ZERO HEIGHTS...WILL MENTION
SCATTERED RAIN/SNOW SHOWERS THURSDAY EXCEPT HIGHER POPS ON LAKE
HURON...AND CONTINUE CHANCE LIGHT SNOW SHOWER MENTION THUMB/LAKE
HURON IN MODEST LAKE EFFECT THURSDAY NIGHT/FRIDAY.
THEREAFTER...CHANCE OF SNOW SHOWERS OR MIX FRIDAY AND OF RAIN
SHOWERS OR MIX SATURDAY.
AFTER SATURDAY...
OVERALL LOW CONFIDENCE IN DETAILS OF FORECAST FOR THIS PERIOD...AS
MODEL DIFFERENCES CONTINUE LARGE...BOTH AMONG MODELS AND FROM RUN TO
RUN WITHIN MODELS.
AT 500 MB...SOME MODEL CONSENSUS TOWARD SHORTWAVE TROUGH PIVOTING
AWAY FROM THE NORTHERN/EASTERN GREAT LAKES REGION SATURDAY NIGHT
FOLLOWED BY A BIT OF RIDGING THROUGH SUNDAY. THEREAFTER...THE 00Z
GFS AND 06Z DGEX SHOWED NORTHERN STREAM ENERGY MAKING A DENT IN
HEIGHTS OVER THE LAKES REGION THROUGH MONDAY BEFORE RISING
HEIGHTS/RIDGING PREVAILS INTO MID WEEK AS WESTERN TROUGH EVOLVES.
THE 06Z GFS...BY STARK CONTRAST...SHOWED LESS OF A NORTHERN STREAM
DENT MONDAY AND MUCH FASTER EVOLUTION/PROGRESSION OF WESTERN TROUGH
AND BREAKDOWN OF RIDGE OVER THE GREAT LAKES. THIS 06Z SOLUTION WAS
LEANING TOWARD THE 00Z ECMWF. THE OVERNIGHT WRFHEMI EMPHASIZED A
HUGE EASTERN CANADIAN LOW AFFECTING THE LAKES REGION FOR MOST OF THE
PERIOD. THE 00Z GFS ENSEMBLE MEMBERS SHOWED MUCH DIVERSITY...
ESPECIALLY TOWARD MID WEEK.
AT THE SURFACE...SOME MODEL CONSENSUS OF A LARGE HIGH PRESSURE
SYSTEM CENTERED NEAR OR NORTH OF LAKE SUPERIOR AT THE START OF THE
PERIOD WITH SUBSEQUENT EASTWARD DRIFT THROUGH MONDAY. MODELS VARY
GREATLY AS TO HOW QUICK TO MOVE A COLD FRONT IN/THROUGH THE AREA
FROM THE WEST. THE 00Z WRFHEMI/00Z OPERATIONAL AND ENSEMBLE MEAN OF
THE GFS...AND 06Z DGEX SHOWED THIS FRONT IN THE AREA MONDAY AS
OPPOSED TO THE TUESDAY TIME FRAME AS PER ECMWF AND 06Z GFS. OVERALL
GROWING CONSENSUS EXISTS TOWARD HIGH PRESSURE HAVING TROUBLE NOSING
IN FROM THE NORTHERN PLAINS...AS FRONT STALLS OVER THE SOUTHERN
LAKES REGION AND ONE OR MORE WEAK WAVES MOVES NORTHEAST ALONG THE
FRONT. THIS LATTER IDEA EXPRESSED BY THE 00Z ECMWF AND ALSO THE 12Z
OPERATIONAL GFS.
THEREFORE...WILL CONTINUE WITH SLIGHT CHANCE LIGHT SNOW SHOWERS
SATURDAY NIGHT AND SUNDAY ESPECIALLY NEAR LAKE HURON FOR MODEST LAKE
EFFECT. THEN...CHANCE OF RAIN SHOWERS BEGINNING MONDAY NIGHT AND
CONTINUING THROUGH WEDNESDAY WITH FRONT AND PROBABLE WAVES ALONG THE
FRONT ALBEIT IN PRESENCE OF WARMER TEMPERATURES.
&&
.MARINE...
WESTERLY WIND GUSTS OF 20 TO 30 KNOTS THIS AFTERNOON ARE EXPECTED TO
DIMINISH A GOOD 5 KNOTS THIS EVENING/TONIGHT ALONG THE NEARSHORE
WATERS AS WE LOSE DAYTIME HEATING AND BOUNDARY LAYER COOLS. A
SECONDARY COLD FRONT PUSHING THROUGH THE CENTRAL GREAT LAKES
TOMORROW MORNING WILL BRING AN INCREASE TO THE WINDS BY
AFTERNOON...WITH SMALL CRAFT ADVISORY WINDS EXPECTED TO RETURN OVER
ALL MARINE AREAS. A RIDGE OF HIGH PRESSURE IS FORECASTED TO BUILD
INTO THE CENTRAL GREAT LAKES ON FRIDAY WITH WINDS BECOMING LIGHT.
LIGHT WINDS ARE EXPECTED TO PERSIST INTO SATURDAY AS A WEAK AREA OF
LOW PRESSURE TRAVERSES THROUGH THE SOUTHERN GREAT LAKES.
&&
.PREV DISCUSSION...ISSUED 1212 PM EST WED NOV 14 2007
AVIATION...
THE LOW LEVELS HAVE DRIED OUT EARLY THIS AFTERNOON...WHICH SHOULD
ALLOW FOR CLEAR SKIES (BELOW 12000 FEET) TO PERSIST INTO THE EVENING
HOURS. HOWEVER...WESTERLY WINDS WILL REMAIN GUSTY UP TO 25 KNOTS
THIS AFTERNOON BEFORE DECREASING. A SECONDARY COLD FRONT WILL
APPROACH SOUTHEAST MICHIGAN TONIGHT...BRINGING WITH IT A BROKEN
LOWER VFR STRATUS DECK (AROUND 4000 FEET) AFTER MIDNIGHT. ENOUGH
COLD AIR ARRIVES TOMORROW MORNING TO PRODUCE INSTABILITY SNOW/RAIN
SHOWERS OFF LAKE MICHIGAN...WHICH WILL LIKELY PRODUCE SCATTERED
MVFR VSBYS/CEILINGS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...LHZ422-LHZ442-LHZ443...UNTIL 7 PM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT SANILAC TO PORT
HURON...FROM 10 AM THURSDAY TO 7 PM FRIDAY.
SMALL CRAFT ADVISORY...INNER SAGINAW BAY...FROM 10 AM THURSDAY TO
11 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR
BEACH...UNTIL 7 PM FRIDAY.
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY...UNTIL NOON FRIDAY.
LAKE ST CLAIR...
SMALL CRAFT ADVISORY...FROM 10 AM THURSDAY TO 11 PM THURSDAY.
MI WATERS OF LAKE ERIE...
SMALL CRAFT ADVISORY...FROM 10 AM THURSDAY TO 11 PM THURSDAY.
&&
$$
SHORT TERM...SF
LONG TERM....DWD
MARINE.......SF
AVIATION.....SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1218 PM CST WED NOV 14 2007
.UPDATE...
UPDATED FOR AVIATION DISCUSSION BELOW.
&&
.DISCUSSION... /ISSUED 312 AM CST WED NOV 14 2007/
THE PRIMARY FORECAST CHALLENGES ARE THE WIND SPEEDS TODAY AND THE
TEMPS THROUGH THE NEXT 48 HOURS.
GOES WV LOOP REVEALING STACKED COLD CORE LOW SLOWING ITS EASTWARD
MOMENTUM OVER ONTARIO. CYCLONIC LOW LEVEL FLOW DROVE COLD FRONT
NUMBER ONE THROUGH THE FORECAST AREA DURING LAST EVE AND COLD
FRONT NUMBER TWO IS HEADED DOWN THE RED RIVER VALLEY EARLY THIS
MORNING. TWO EARLY MORNING AIRCRAFT TAMDAR SOUNDINGS AND 88D
PROFILERS BOTH INDICATE 50-65 KTS OF NORTHWEST FLOW WITHIN THE
850-925MB LAYER ACROSS THE EASTERN DAKOTAS. THIS WILL HELP TO
PROMOTE WINDS TO ADVISORY CRITERIA A LITTLE EARLIER IN WRN MN SO
HAVE MOVED FORWARD THE ADVISORY. CURRENT SURFACE OBS ALONG THE
I-29 CORRIDOR ARE ALREADY REFLECTING 40 MPH GUSTS. PROGNOSTIC
SOUNDINGS FROM THE 06Z 40KM RUC AND 12KM NAM INDICATE DRY
ADIABATIC LAPSE RATES DEVELOPING FROM THE SURFACE UP TO ABOVE 850
MB BY 9 AM. THIS IS WITH SURFACE TEMPS ONLY AROUND 40F AT THAT.
ANY WARMER AND A SLIGHTLY SUPERADIABATIC COMPONENT NEAR THE
SURFACE DEVELOPS BY 18Z WHICH MAY MEAN EVEN STRONGER SUSTAINED
WINDS OF 35 MPH IN PLACES. SOME GUSTS TO 45 MPH ARE LIKELY OVER
WEST CENTRAL MN GIVEN STRONGER SPEEDS TO MIX DOWN. WE ALSO HAVE
EXPANDED THE ADVISORY SLIGHTLY EAST IN SOUTH CENTRAL MN TO REFLECT
CURRENT THINKING.
WITH THE STRONG LOW LEVEL COLD AND DRY AIR ADVECTION AND THE
CYCLONIC STRATOCU...THE TEMPS WILL HOLD STEADY IN MANY COMMUNITIES
TODAY...AND MAY ACTUALLY DROP A HANDFUL OF DEGREES IN CTRL MN.
EMBEDDED VORT LOBE DRIVING THE SECONDARY COLD FRONT WILL PASS
DURING THE AFTERNOON AND POSSIBLY LEAD TO A LIGHT SHOWER OR FLURRY
OVER CTRL MN AND WRN WI. THE 03Z SHORT RANGE ENSEMBLE FIELDS
REFLECT THIS WITH TOTAL TOTAL INDICES NEAR 50 OVER THIS AREA THIS
AFTN.
THE CYCLONIC FLOW WILL REMAIN OVER THE REGION THROUGH THU. THE LOW
CLOUDS SHOULD HOLD STEADY THROUGH AT LEAST THU MORNING BEFORE
SOME PULL TO THE EAST BEGINS WITH SYSTEM DEPARTURE. A WEAK SHORT
WAVE IN THE NORTHWEST FLOW IS BECOMING EVIDENT DURING FRIDAY ON
GUIDANCE. WINDOW OF THETA-E RETURN IN THE 700MB AND BELOW LAYER IS
VERY BRIEF AND WEAK ON THE ADIABATIC CHARTS. SO NO ADDED MENTION
OF A SHOWER AT THIS POINT. BAROCLINIC ZONE AT 850MB LIFTS OVER
THE AREA DURING THE WEEKEND. THE LIFT ALONG THIS HAS
PROGRESSIVELY BECOME STRONGER IN SOLUTIONS AND NOW WARRANTS A
SLIGHT CHANCE OF SOME LIGHT RAIN OR SNOW IN CTRL MN INTO PARTS OF
WEST CTRL WI DURING SAT NIGHT AND SUN. MORE CLOUDS AND SLIGHTLY
COOLER TEMPS HAVE BEEN ADDED AS WELL DURING THAT TIME.
IN THE LONG RANGE...MANY UNCERTAINTIES EXIST FOR THANKSGIVING
WEEK. JUST A QUICK COMPARATIVE GLANCE AT THE 500MB HEIGHTS AND 850MB
THETA-E ON THE GFS AND ECMWF IN CURRENT AND PAST RUNS SHOW WIDE
DISCREPANCIES IN UPPER FLOW AND LOW LEVEL BAROCLINIC ZONE AREA.
STILL LOOKS LIKE A HUDSON BAY TROUGH WILL EXTEND INTO PART OF THE
GREAT LAKES...KEEPING THE UPPER FLOW AT LEAST WESTERLY IF NOT
NORTHWESTERLY DURING THE MIDDLE OF THE WEEK. THIS ALONG WITH
13/12Z HPC 6-10 DAY GUIDANCE WOULD IMPLY TEMPS NEAR OR BELOW
NORMAL. ...MTF...
.AVIATION...
STRONG NW WINDS THE MAIN CONCERN TODAY. ABERDEEN 12Z SOUNDING DRY
ADIABATIC AND EXCELLENT DIRECTIONAL HOOKUP UP TO 750 MB...AND
MODEL SOUNDINGS INDICATE DRY ADIABATIC PROFILES BECOMING PREVALENT
ACROSS WC INTO SC MN. AXN AND RWF TAFS CARRY THE STRONGEST WINDS
WITH GUSTS AROUND 40 KNOTS. A VARIETY OF SITES IN WC/SW MN INTO SD
HAVE BEEN GUSTING AROUND 40 LATE IN THE MORNING. GUSTINESS SHOULD
DIMINISH SOMEWHAT THIS EVENING BUT NOT COMPLETELY. GRADIENT
LESSENS LATER TONIGHT BUT STILL SUGGEST WINDS AROUND 10-15 KNOTS.
ONLY OTHER MATTER OF CONCERN IS CANOPY OF LOW CLOUDS. 40KM NAM
STREAMLINES SHOW CYCLONIC CURVATURE CONTINUING UNTIL LATE TONIGHT
AND THURSDAY MORNING...SO HAVE KEPT BKN-OVC THROUGH THE NIGHT.
SOME BREAKS IN CLOUDS OVER ERN ND AND EXTREME WC MN SHUD SLIDE SE
OR SSE... PROBABLY INTO KRWF FOR A PERIOD LATE AFTERNOON OR
EVENING.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR CHIPPEWA-DOUGLAS-
KANDIYOHI-LAC QUI PARLE-POPE-STEARNS-STEVENS-SWIFT-TODD-
YELLOW MEDICINE COUNTY(IES).
WIND ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR BLUE EARTH-BROWN-
FARIBAULT-FREEBORN-LE SUEUR-MARTIN-MCLEOD-MEEKER-NICOLLET-
REDWOOD-RENVILLE-SIBLEY-WASECA-WATONWAN COUNTY(IES).
WI...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
312 AM CST WED NOV 14 2007
.DISCUSSION...
THE PRIMARY FORECAST CHALLENGES ARE THE WIND SPEEDS TODAY AND THE
TEMPS THROUGH THE NEXT 48 HOURS.
GOES WV LOOP REVEALING STACKED COLD CORE LOW SLOWING ITS EASTWARD
MOMENTUM OVER ONTARIO. CYCLONIC LOW LEVEL FLOW DROVE COLD FRONT
NUMBER ONE THROUGH THE FORECAST AREA DURING LAST EVE AND COLD
FRONT NUMBER TWO IS HEADED DOWN THE RED RIVER VALLEY EARLY THIS
MORNING. TWO EARLY MORNING AIRCRAFT TAMDAR SOUNDINGS AND 88D
PROFILERS BOTH INDICATE 50-65 KTS OF NORTHWEST FLOW WITHIN THE
850-925MB LAYER ACROSS THE EASTERN DAKOTAS. THIS WILL HELP TO
PROMOTE WINDS TO ADVISORY CRITERIA A LITTLE EARLIER IN WRN MN SO
HAVE MOVED FORWARD THE ADVISORY. CURRENT SURFACE OBS ALONG THE
I-29 CORRIDOR ARE ALREADY REFLECTING 40 MPH GUSTS. PROGNOSTIC
SOUNDINGS FROM THE 06Z 40KM RUC AND 12KM NAM INDICATE DRY
ADIABATIC LAPSE RATES DEVELOPING FROM THE SURFACE UP TO ABOVE 850
MB BY 9 AM. THIS IS WITH SURFACE TEMPS ONLY AROUND 40F AT THAT.
ANY WARMER AND A SLIGHTLY SUPERADIABATIC COMPONENT NEAR THE
SURFACE DEVELOPS BY 18Z WHICH MAY MEAN EVEN STRONGER SUSTAINED
WINDS OF 35 MPH IN PLACES. SOME GUSTS TO 45 MPH ARE LIKELY OVER
WEST CENTRAL MN GIVEN STRONGER SPEEDS TO MIX DOWN. WE ALSO HAVE
EXPANDED THE ADVISORY SLIGHTLY EAST IN SOUTH CENTRAL MN TO REFLECT
CURRENT THINKING.
WITH THE STRONG LOW LEVEL COLD AND DRY AIR ADVECTION AND THE
CYCLONIC STRATOCU...THE TEMPS WILL HOLD STEADY IN MANY COMMUNITIES
TODAY...AND MAY ACTUALLY DROP A HANDFUL OF DEGREES IN CTRL MN.
EMBEDDED VORT LOBE DRIVING THE SECONDARY COLD FRONT WILL PASS
DURING THE AFTERNOON AND POSSIBLY LEAD TO A LIGHT SHOWER OR FLURRY
OVER CTRL MN AND WRN WI. THE 03Z SHORT RANGE ENSEMBLE FIELDS
REFLECT THIS WITH TOTAL TOTAL INDICES NEAR 50 OVER THIS AREA THIS
AFTN.
THE CYCLONIC FLOW WILL REMAIN OVER THE REGION THROUGH THU. THE LOW
CLOUDS SHOULD HOLD STEADY THROUGH AT LEAST THU MORNING BEFORE
SOME PULL TO THE EAST BEGINS WITH SYSTEM DEPARTURE. A WEAK SHORT
WAVE IN THE NORTHWEST FLOW IS BECOMING EVIDENT DURING FRIDAY ON
GUIDANCE. WINDOW OF THETA-E RETURN IN THE 700MB AND BELOW LAYER IS
VERY BRIEF AND WEAK ON THE ADIABATIC CHARTS. SO NO ADDED MENTION
OF A SHOWER AT THIS POINT. BAROCLINIC ZONE AT 850MB LIFTS OVER
THE AREA DURING THE WEEKEND. THE LIFT ALONG THIS HAS
PROGRESSIVELY BECOME STRONGER IN SOLUTIONS AND NOW WARRANTS A
SLIGHT CHANCE OF SOME LIGHT RAIN OR SNOW IN CTRL MN INTO PARTS OF
WEST CTRL WI DURING SAT NIGHT AND SUN. MORE CLOUDS AND SLIGHTLY
COOLER TEMPS HAVE BEEN ADDED AS WELL DURING THAT TIME.
IN THE LONG RANGE...MANY UNCERTAINTIES EXIST FOR THANKSGIVING
WEEK. JUST A QUICK COMPARATIVE GLANCE AT THE 500MB HEIGHTS AND 850MB
THETA-E ON THE GFS AND ECMWF IN CURRENT AND PAST RUNS SHOW WIDE
DISCREPANCIES IN UPPER FLOW AND LOW LEVEL BAROCLINIC ZONE AREA.
STILL LOOKS LIKE A HUDSON BAY TROUGH WILL EXTEND INTO PART OF THE
GREAT LAKES...KEEPING THE UPPER FLOW AT LEAST WESTERLY IF NOT
NORTHWESTERLY DURING THE MIDDLE OF THE WEEK. THIS ALONG WITH
13/12Z HPC 6-10 DAY GUIDANCE WOULD IMPLY TEMPS NEAR OR BELOW
NORMAL.
&&
.AVIATION...
BAND OF LIGHT RAIN ASSOCIATED WITH FROPA AND UPPER TROUGH SHOULD
EXIT WEST CENTRAL WISCONSIN AROUND 06Z. SOME AC/CIRRUS POSSIBLE
ACROSS AREA THEREAFTER...BEFORE MORE SIGNIFICANT CAA AND GRADIENT WINDS
DEVELOP WED MORNING. MODELS INDICATE LOW LEVEL RH OR STRATOCUMULUS
DECK SHOULD DROP SOUTH OVER AT LEAST CENTRAL MN/MUCH OF WC WI BY MID
MORNING WED. WILL MENTION SOME MVFR CIGS DEVELOPING ACROSS ALL OF
TAF SITES BY 18Z. MAY SEE A FLURRY OVER THE NORTHERN CWA WED
AFTERNOON AS WELL. WILL LEAVE OUT OF RWF/MSP TAFS FOR NOW. WEST TO
NORTHWEST WINDS WILL INCREASE WEDNESDAY MORNING SA WELL...WITH SOME
40KT PLUS WIND GUSTS LIKELY DEVELOPING WC/SW MN. LOW CLOUDS
EXPECTED TO HOLD FIRM THROUGH 06Z AS COLD CORE MOVES ACROSS THE
AREA.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND ADVISORY FROM 6 AM THIS MORNING TO 6 PM CST THIS AFTERNOON
FOR CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-POPE-STEARNS-
STEVENS-SWIFT-TODD-YELLOW MEDICINE COUNTIES.
WIND ADVISORY FROM 9 AM THIS MORNING TO 6 PM CST THIS AFTERNOON
FOR BLUE EARTH-BROWN-FARIBAULT-FREEBORN-LE SUEUR-MARTIN-
MCLEOD-MEEKER-NICOLLET-REDWOOD-RENVILLE-SIBLEY-
WATONWAN COUNTIES.
WI...NONE.
&&
$$
MTF/DWE
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
255 PM CST WED NOV 14 2007
.DISCUSSION...
TIGHT PRESSURE GRADIENT BETWEEN EXITING LOW AND SFC HIGH PUSHING
INTO NORTHERN ROCKIES. WITH GUSTS STILL TO 45KTS...WILL KEEP THE
WIND ADVISORY GOING UNTIL AT LEAST 00Z. THE BIG QUESTION IS
WHETHER OR NOT THE WINDS WILL DROP OFF AS THE SUN GOES DOWN. H8
WINDS REMAIN AT 40-45KTS OVER THE EASTERN PART OF THE FORECAST
AREA THROUGH 06Z. MAY NEED TO EXTEND THE WIND ADVISORY TO 02Z WHEN
THE INVERSION REALLY STARTS TO DECOUPLE THE WINDS.
MODELS ARE IN PRETTY GOOD AGREEMENT THROUGH ABOUT SUN WITH
NORTHWEST FLOW OVER THE AREA. HOWEVER...AFTER SUN THERE IS QUITE A
BIT OF DIFFERENCE. THE GFS KEEPS THE SYSTEM AS AN OPEN WAVE THAT
STARTS OUT OVER THE INTERMOUNTAIN WEST TUE AND THEN DROPS THE MAIN
UPPER LOW DOWN INTO WESTERN TX BY FRI MORNING. THE ECMWF CUTS THE
LOW OFF OVER THE INTERMOUNTAIN WEST AND MOVES IT VERY SLOWLY
EASTWARD. IN THIS SCENARIO...THE ONSET OF PCPN WOULD HOLD OFF
UNTIL WED BUT WOULD LINGER INTO THE WEEKEND. THIS WILL NEED TO BE
WATCHED OVER THE NEXT SEVERAL RUNS AS THIS WILL IMPACT HOLIDAY
TRAVELERS. LOOKS LIKE SOME OVERRUNNING CLOUDS AND PCPN WILL
DEVELOP AND WITH H8 TEMPS DROPPING WELL BELOW ZERO...EXPECT SNOW
OVER THE NORTHERN PORTION OF THE CWA WITH RAIN POSSIBLY MIXED WITH
SNOW SOUTH TUE AND WED.
&&
.AVIATION...
VFR CONDITIONS SHOULD BE IN PLACE ACROSS NEBRASKA INTO THE FRONT
RANGE OF THE ROCKIES OVER THE NEXT 24 HOURS. THE MAIN CONCERN TO
LIGHT AIRCRAFT WILL BE NORTHWEST WINDS GUSTING OVER 40 MPH THROUGH
SUNSET ACROSS THE AREA. AFTER SUNSET THESE WINDS ARE EXPECTED TO
QUICKLY CALM DOWN.
.FIRE WEATHER...
DRY ATMOSPHERE...DRY FUELS AND BREEZY CONDITIONS WILL ONCE AGAIN
ELEVATE FIRE WEATHER CONCERNS THURSDAY AFTERNOON. RH LEVELS WILL
DROP TO NEAR 20 PERCENT MAINLY ALONG AND SOUTH OF INTERSTATE 80 BY
MID AFTERNOON ON THURSDAY...THIS ALONG WITH SOUTHERLY WINDS OF 15 TO
25 MPH SHOULD BRING NEAR CRITICAL FIRE WEATHER CONDITIONS AND WILL
BE MONITORED FOR FIRE HEADLINES. FIRE STARTS HAVE BEEN MORE NUMEROUS
THE PAST FEW WEEKS WITH THE EXTENDED DRY AND WARM PERIOD LEADING TO
EXTENDED OUTDOOR RECREATION AND AGRICULTURAL OPPORTUNITIES.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 8 PM CST /7 PM MST/ THIS EVENING FOR
NEZ004>010-022>029-035>038-056-057-059-094.
&&
$$
13/75
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
1004 AM CST WED NOV 14 2007
.UPDATE...
HAVE UPDATED FORECAST FOR FLURRIES/LIGHT SNOW SHOWERS MOVING ACROSS
THE BORDER FROM NORTH DAKOTA WHERE MORE WIDESPREAD SNOW SHOWERS
WERE OCCURRING. THIS WILL CONTINUE THROUGH THE AFTERNOON UNTIL THE SATURATED
LATER BETWEEN H7 AND H8 LAYERS BEGINS TO DRY. OTHERWISE GOING
FORECAST IS GOOD AND WILL CONTINUE WIND ADVISORY THROUGH 00Z.
&&
.PREV DISCUSSION...
.SHORT TERM...TODAY THROUGH FRIDAY
SECONDARY COLD FRONT WILL BE MAKING ITS WAY THROUGH THE CWA EARLY
THIS MORNING. LOW CLOUDS WERE ALONG THE LEADING EDGE OF THE COLD
FRONT ALONG WITH A MARKED INCREASE IN WINDS. WIND GUSTS OVER 50
MPH HAVE BEEN REPORTED IN ND AS THE FRONT PASSED THROUGH.
OTHERWISE...MODEL SOUNDINGS ACROSS THE CWA POINT TO A DEEP MIXED
LAYER THROUGH THE DAY WITH DEEP STRONG NORTHWEST WINDS ALONG WITH
A CLOUD LAYER MOVING IN/FORMING AT MOST LOCATIONS THROUGH THIS
MORNING. THUS...THE WIND ADVISORY LOOKS GOOD THROUGH 6 PM CST
TODAY. WITH CAA ALONG WITH THE LOW CLOUDS MOVING IN...THE HIGH
TEMPERATURES FOR TODAY WILL BE EARLY THIS MORNING ACROSS MUCH OF
THE NORTHERN AND EASTERN CWA. EXPECT THE LOW CLOUDS TO REMAIN IN
ACROSS MUCH OF THE EASTERN CWA THROUGH THIS EVENING. WITH THE
SURFACE HIGH PRESSURE RIDGE REMAINING OFF TO THE WEST OF THE CWA
AND A DECENT SURFACE PRESSURE GRADIENT...NORTHWEST WINDS WILL DROP
OFF SOME THIS EVENING. AS THE CLOUDS MOVE OUT AND THE PRESSURE
GRADIENT LOOSENS...THE WINDS WILL DROP OFF QUITE A
BIT...ESPECIALLY WEST IN THE CWA AFTER MIDNIGHT. LOWS TONIGHT WILL
BE TRICKY...DEPENDING ON WHEN THE SKIES CLEAR AND WINDS DROP OFF.
THE SURFACE HIGH PRESSURE RIDGE QUICKLY BUILDS EAST ON THURSDAY
WITH WINDS BECOMING SOUTH. THURSDAY WILL BE A LITTLE WARMER THAN
TODAY WITH 85H TEMPERATURES RISING ALONG WITH MORE SUNSHINE. THE
MODEL SOUNDINGS AND SURFACE CHARTS SHOW A WARM FRONT RETURNING
THURSDAY NIGHT AND FRIDAY MORNING. INDICATIONS ARE THAT MID AND
HIGH CLOUDS WILL INCREASE...HELPING KEEP TEMPERATURES UP ON
THURSDAY NIGHT AND COULD TEMPER WARMING ON FRIDAY.
ALTHOUGH...FRIDAY WILL STILL BE WARMER THAN THURSDAY WITH NOT MUCH
WIND. INCREASED HIGHS FOR FRIDAY. THERE MAY BE SOME MID LEVEL
LIGHT SNOW/FLURRIES WITH THE WAA ON THURSDAY NIGHT AND EARLY
FRIDAY AS SHOWN BY THE GFS. WITH THE VERY DRY LOW LEVELS...WILL
KEEP PRECIPITATION CHANCES OUT AT THIS POINT.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
FORECAST CHALLENGES...PRECIPITATION POTENTIAL AND TYPE SATURDAY
NIGHT INTO SUNDAY MORNING...ALONG WITH TEMPERATURES ON SATURDAY.
NO SIGNIFICANT CHANGES IN THE 00Z GFS/EC SOLUTIONS. BOTH MODELS
APPEAR TO BE CONVERGING ON A FAIRLY SIGNIFICANT LONGWAVE TROF AND
UPPER CIRCULATION CENTER OVER THE CENTRAL ROCKIES BY THE MIDDLE OF
NEXT WEEK. UNTIL THEN...THE FLOW PATTERN ALOFT CONTINUES TO BE
ONE OF EITHER NW FLOW OR FASTER ZONAL FLOW. CAVEAT TO TEMPERATURES
ON SATURDAY...THE 00Z GFS SOLUTION INDICATES A LITTLE BIT OF
SHALLOW COLD AIR INTRUDING INTO THE FORECAST AREA FROM THE
NORTHEAST FRIDAY NIGHT AND INTO SATURDAY /BEST SEEN IN THE 925HPA
THERMAL PROGS/. THIS WAS HANDLED WELL IN THE GRIDS...SO NO REAL
CHANGE NOTED THERE. AN UPPER WAVE OF MODERATE
STRENGTH/DYNAMICS...AS PROGGED IN THE 00Z GFS RUN...IS SET TO
SWEEP THROUGH NORTH DAKOTA AND NORTHERN MINNESOTA SATURDAY NIGHT
AND SUNDAY. THERE IS SOME STRONG UPPER LEVEL JET SUPPORT FOR
ENHANCEMENT OF MID-LEVEL FORCING...HOWEVER ADEQUATE LOW/MID LEVEL
MOISTURE TO PRODUCE MORE THAN VIRGA ACROSS THE NERN THIRD OF
FORECAST ZONES SATURDAY NIGHT INTO EARLY SUNDAY REMAINS TO BE
SEEN. DID TOSS IN A TOKEN 20 POP TO BLEND UP TO NORTHERN BORDERING
NEIGHBOR FOR SATURDAY NIGHT. PRECIPITATION TYPE MAY START OUT AS
SOME LIGHT RAIN OR LIGHT FREEZING RAIN...BUT AS THE COLUMN
SATURATES/COOLS...COULD SEE SOME LIGHT SNOW IN THE MIX AS WELL.
TEMPERATURES ON SUNDAY APPEAR SIMILAR TO THOSE OF SATURDAY IN
MAINLY NEUTRAL THERMAL ADVECTION PATTERN LEADING INTO NEXT WEEK.
NO CHANGES MADE BEYOND SUNDAY...ALTHOUGH...COULD BE LOOKING AT A
BETTER SHOT AT SOME OVER-RUNNING/WAA-TYPE PRECIPITATION BY MID TO
LATE NEXT WEEK...DEPENDING ON EVOLUTION AND TRACK OF UPPER
CIRCULATION PROGGED TO SET UP SHOP OVER CENTRAL ROCKIES BY NEXT
TUESDAY NIGHT.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL OVERNIGHT AND INTO THE DAY ON
WEDNESDAY...ALTHOUGH A SCATTERED TO BROKEN DECK OF STRATUS CLOUDS
/WITH BASES FROM 3500 TO 6500 FT AGL/ WILL SWEEP SOUTHWARD ACROSS
THE KABR AND KATY TERMINALS FOR MUCH OF THE TAF VALID PERIOD. THE
KMBG AND KPIR TERMINALS SHOULD REMAIN CLEAR OF ANY OF THESE
STRATUS CLOUDS.
WIND SPEEDS WILL BE THE REAL CHALLENGE OVER THE NEXT 18 HOURS OR
SO. LOW LEVEL WIND SHEAR IS EXPECTED ACROSS MUCH OF THE
REGION...PER 04Z-05Z TAMDAR SOUNDING DATA AT THE KATY...KABR AND
KPIR TERMINALS UNTIL THE RATHER STRONG WINDS SWEEPING SOUTHWARD
OUT OF NORTH DAKOTA REACH THE TERMINALS IN THIS FORECAST AREA. AT
THE SURFACE WEST WINDS BETWEEN 15 AND 25 KNOTS TURN TO A NORTHWEST
DIRECTION AROUND 55 TO 60 KNOTS WITHIN THE FIRST THOUSAND FEET OF
THE ATMOSPHERE. HOWEVER...ONCE A REINFORCING SHOT OF COLD AIR
/ACCOMPANYING THE STRATUS CLOUDS/ REACHES THIS FORECAST
AREA...WINDS WILL SWITCH AROUND TO THE NORTHWEST AND INCREASE AT
THE SURFACE TO 25 TO 35 KNOTS WITH HIGHER GUSTS. THIS WIND SHIFT
AND INCREASE IN SPEED SHOULD OCCUR AT ALL 4 TERMINALS BETWEEN 08Z
AND 11Z THIS MORNING...AND PERSIST WELL INTO THE AFTERNOON ON
WEDNESDAY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS AFTERNOON FOR BROWN-
BUFFALO-CAMPBELL-CLARK-CODINGTON-CORSON-DAY-DEUEL-DEWEY-
EDMUNDS-FAULK-GRANT-HAMLIN-HAND-HUGHES-HYDE-JONES-LYMAN-
MARSHALL-MCPHERSON-POTTER-ROBERTS-SPINK-STANLEY-SULLY-
WALWORTH.
MN...WIND ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR BIG STONE-
TRAVERSE.
&&
$$
UPDATE...CONNELLY
SHORT TERM...MOHR
LONG TERM...DORN
AVIATION...DORN
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
322 AM CST WED NOV 14 2007
.SHORT TERM...TODAY THROUGH FRIDAY
SECONDARY COLD FRONT WILL BE MAKING ITS WAY THROUGH THE CWA EARLY
THIS MORNING. LOW CLOUDS WERE ALONG THE LEADING EDGE OF THE COLD
FRONT ALONG WITH A MARKED INCREASE IN THE WINDS. WIND GUSTS OVER
50 MPH HAVE BEEN REPORTED IN ND AS THE FRONT PASSED THROUGH.
OTHERWISE...MODEL SOUNDINGS ACROSS THE CWA POINT TO A DEEP MIXED
LAYER THROUGH THE DAY WITH DEEP STRONG NORTHWEST WINDS ALONG WITH
A CLOUD LAYER MOVING IN/FORMING AT MOST LOCATIONS THROUGH THIS
MORNING. THUS...THE WIND ADVISORY LOOKS GOOD THROUGH 6 PM CST
TODAY. WITH CAA ALONG WITH THE LOW CLOUDS MOVING IN...THE HIGH
TEMPERATURES FOR TODAY WILL BE EARLY THIS MORNING ACROSS MUCH OF
THE NORTHERN AND EASTERN CWA. EXPECT THE LOW CLOUDS TO REMAIN IN
ACROSS MUCH OF THE EASTERN CWA THROUGH THIS EVENING. WITH THE
SURFACE HIGH PRESSURE RIDGE REMAINING OFF TO THE WEST OF THE CWA
AND A DECENT SURFACE PRESSURE GRADIENT...NORTHWEST WINDS WILL DROP
OFF SOME THIS EVENING. AS THE CLOUDS MOVE OUT AND THE PRESSURE
GRADIENT LOOSENS...THE WINDS WILL DROP OFF QUITE A
BIT...ESPECIALLY WEST IN THE CWA AFTER MIDNIGHT. LOWS TONIGHT WILL
BE TRICKY...DEPENDING ON WHEN THE SKIES CLEAR AND WINDS DROP OFF.
THE SURFACE HIGH PRESSURE RIDGE QUICKLY BUILDS EAST ON THURSDAY
WITH WINDS BECOMING SOUTH. THURSDAY WILL BE A LITTLE WARMER THAN
TODAY WITH 85H TEMPERATURES RISING ALONG WITH MORE SUNSHINE. THE
MODEL SOUNDINGS AND SURFACE CHARTS SHOW A WARM FRONT RETURNING
THURSDAY NIGHT AND FRIDAY MORNING. INDICATIONS ARE THAT MID AND
HIGH CLOUDS WILL INCREASE...HELPING KEEP TEMPERATURES UP ON
THURSDAY NIGHT AND COULD TEMPER WARMING ON FRIDAY.
ALTHOUGH...FRIDAY WILL STILL BE WARMER THAN THURSDAY WITH NOT MUCH
WIND. INCREASED HIGHS FOR FRIDAY. THERE MAY BE SOME MID LEVEL
LIGHT SNOW/FLURRIES WITH THE WAA ON THURSDAY NIGHT AND EARLY
FRIDAY AS SHOWN BY THE GFS. WITH THE VERY DRY LOW LEVELS...WILL
KEEP PRECIPITATION CHANCES OUT AT THIS POINT.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
FORECAST CHALLENGES...PRECIPITATION POTENTIAL AND TYPE SATURDAY
NIGHT INTO SUNDAY MORNING...ALONG WITH TEMPERATURES ON SATURDAY.
NO SIGNIFICANT CHANGES IN THE 00Z GFS/EC SOLUTIONS. BOTH MODELS
APPEAR TO BE CONVERGING ON A FAIRLY SIGNIFICANT LONGWAVE TROF AND
UPPER CIRCULATION CENTER OVER THE CENTRAL ROCKIES BY THE MIDDLE OF
NEXT WEEK. UNTIL THEN...THE FLOW PATTERN ALOFT CONTINUES TO BE
ONE OF EITHER NW FLOW OR FASTER ZONAL FLOW. CAVEAT TO TEMPERATURES
ON SATURDAY...THE 00Z GFS SOLUTION INDICATES A LITTLE BIT OF
SHALLOW COLD AIR INTRUDING INTO THE FORECAST AREA FROM THE
NORTHEAST FRIDAY NIGHT AND INTO SATURDAY /BEST SEEN IN THE 925HPA
THERMAL PROGS/. THIS WAS HANDLED WELL IN THE GRIDS...SO NO REAL
CHANGE NOTED THERE. AN UPPER WAVE OF MODERATE
STRENGTH/DYNAMICS...AS PROGGED IN THE 00Z GFS RUN...IS SET TO
SWEEP THROUGH NORTH DAKOTA AND NORTHERN MINNESOTA SATURDAY NIGHT
AND SUNDAY. THERE IS SOME STRONG UPPER LEVEL JET SUPPORT FOR
ENHANCEMENT OF MID-LEVEL FORCING...HOWEVER ADEQUATE LOW/MID LEVEL
MOISTURE TO PRODUCE MORE THAN VIRGA ACROSS THE NERN THIRD OF
FORECAST ZONES SATURDAY NIGHT INTO EARLY SUNDAY REMAINS TO BE
SEEN. DID TOSS IN A TOKEN 20 POP TO BLEND UP TO NORTHERN BORDERING
NEIGHBOR FOR SATURDAY NIGHT. PRECIPITATION TYPE MAY START OUT AS
SOME LIGHT RAIN OR LIGHT FREEZING RAIN...BUT AS THE COLUMN
SATURATES/COOLS...COULD SEE SOME LIGHT SNOW IN THE MIX AS WELL.
TEMPERATURES ON SUNDAY APPEAR SIMILAR TO THOSE OF SATURDAY IN
MAINLY NEUTRAL THERMAL ADVECTION PATTERN LEADING INTO NEXT WEEK.
NO CHANGES MADE BEYOND SUNDAY...ALTHOUGH...COULD BE LOOKING AT A
BETTER SHOT AT SOME OVER-RUNNING/WAA-TYPE PRECIPITATION BY MID TO
LATE NEXT WEEK...DEPENDING ON EVOLUTION AND TRACK OF UPPER
CIRCULATION PROGGED TO SET UP SHOP OVER CENTRAL ROCKIES BY NEXT
TUESDAY NIGHT.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL OVERNIGHT AND INTO THE DAY ON
WEDNESDAY...ALTHOUGH A SCATTERED TO BROKEN DECK OF STRATUS CLOUDS
/WITH BASES FROM 3500 TO 6500 FT AGL/ WILL SWEEP SOUTHWARD ACROSS
THE KABR AND KATY TERMINALS FOR MUCH OF THE TAF VALID PERIOD. THE
KMBG AND KPIR TERMINALS SHOULD REMAIN CLEAR OF ANY OF THESE
STRATUS CLOUDS.
WIND SPEEDS WILL BE THE REAL CHALLENGE OVER THE NEXT 18 HOURS OR
SO. LOW LEVEL WIND SHEAR IS EXPECTED ACROSS MUCH OF THE
REGION...PER 04Z-05Z TAMDAR SOUNDING DATA AT THE KATY...KABR AND
KPIR TERMINALS UNTIL THE RATHER STRONG WINDS SWEEPING SOUTHWARD
OUT OF NORTH DAKOTA REACH THE TERMINALS IN THIS FORECAST AREA. AT
THE SURFACE WEST WINDS BETWEEN 15 AND 25 KNOTS TURN TO A NORTHWEST
DIRECTION AROUND 55 TO 60 KNOTS WITHIN THE FIRST THOUSAND FEET OF
THE ATMOSPHERE. HOWEVER...ONCE A REINFORCING SHOT OF COLD AIR
/ACCOMPANYING THE STRATUS CLOUDS/ REACHES THIS FORECAST
AREA...WINDS WILL SWITCH AROUND TO THE NORTHWEST AND INCREASE AT
THE SURFACE TO 25 TO 35 KNOTS WITH HIGHER GUSTS. THIS WIND SHIFT
AND INCREASE IN SPEED SHOULD OCCUR AT ALL 4 TERMINALS BETWEEN 08Z
AND 11Z THIS MORNING...AND PERSIST WELL INTO THE AFTERNOON ON
WEDNESDAY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS AFTERNOON FOR BROWN-
BUFFALO-CAMPBELL-CLARK-CODINGTON-CORSON-DAY-DEUEL-DEWEY-
EDMUNDS-FAULK-GRANT-HAMLIN-HAND-HUGHES-HYDE-JONES-LYMAN-
MARSHALL-MCPHERSON-POTTER-ROBERTS-SPINK-STANLEY-SULLY-
WALWORTH.
MN...WIND ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR BIG STONE-
TRAVERSE.
&&
$$
SHORT TERM...MOHR
LONG TERM...DORN
AVIATION...DORN
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
949 AM EST WED NOV 14 2007
.DISCUSSION...
A SURFACE COLD FRONT IS CURRENTLY MOVING INTO THE OHIO VALLEY.
AHEAD OF THE FRONT...VISIBLE SATELLITE SHOWS CONVECTIVE CLOUDS OVER
WEST AND MIDDLE TN...INDICATING AN UNSTABLE AIR MASS. BEFORE
THUNDERSTORMS AFFECT OUR AREA...A STRONG MIDLEVEL INVERSION BETWEEN
650 AND 600 MB MUST ERODE. ACARS SOUNDINGS SHOW THIS INVERSION IS
WEAKER TO THE WEST...AND MODEL SOUNDINGS SHOW IT WEAKENING LATE
THIS AFTERNOON WHEN A 600 MB TEMPERATURE GRADIENT PASSES THROUGH. UNTIL
THEN WE SHOULD SEE SCATTERED LIGHT SHOWERS...MAINLY IN NORTHERN
PORTIONS OF THE AREA. PLENTY OF SUN IN THE SOUTHERN AND CENTRAL
TENNESSEE VALLEY THIS MORNING WILL LIKELY ENHANCE THUNDERSTORMS
AND SEVERE POTENTIAL THIS EVENING. WILL ISSUE AN SPS TO MENTION THE
THREAT OF SEVERE THIS EVENING IN SOUTHERN AND WESTERN COUNTIES. THE
FORECAST UPDATE WILL ALSO RAISE TEMPS IN THE SOUTHERN HALF OF THE
AREA.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS
|